diff options
Diffstat (limited to 'libdde_linux26/lib/src/fs')
| -rw-r--r-- | libdde_linux26/lib/src/fs/.svn/all-wcprops | 23 | ||||
| -rw-r--r-- | libdde_linux26/lib/src/fs/.svn/entries | 130 | ||||
| -rw-r--r-- | libdde_linux26/lib/src/fs/.svn/format | 1 | ||||
| -rw-r--r-- | libdde_linux26/lib/src/fs/.svn/text-base/block_dev.c.svn-base | 1422 | ||||
| -rw-r--r-- | libdde_linux26/lib/src/fs/.svn/text-base/buffer.c.svn-base | 3474 | ||||
| -rw-r--r-- | libdde_linux26/lib/src/fs/.svn/text-base/char_dev.c.svn-base | 572 | ||||
| -rw-r--r-- | libdde_linux26/lib/src/fs/block_dev.c | 1422 | ||||
| -rw-r--r-- | libdde_linux26/lib/src/fs/buffer.c | 3474 | ||||
| -rw-r--r-- | libdde_linux26/lib/src/fs/char_dev.c | 572 |
9 files changed, 11090 insertions, 0 deletions
diff --git a/libdde_linux26/lib/src/fs/.svn/all-wcprops b/libdde_linux26/lib/src/fs/.svn/all-wcprops new file mode 100644 index 00000000..b87b0b35 --- /dev/null +++ b/libdde_linux26/lib/src/fs/.svn/all-wcprops @@ -0,0 +1,23 @@ +K 25 +svn:wc:ra_dav:version-url +V 61 +/repos/tudos/!svn/ver/455/trunk/l4/pkg/dde/linux26/lib/src/fs +END +block_dev.c +K 25 +svn:wc:ra_dav:version-url +V 73 +/repos/tudos/!svn/ver/455/trunk/l4/pkg/dde/linux26/lib/src/fs/block_dev.c +END +buffer.c +K 25 +svn:wc:ra_dav:version-url +V 70 +/repos/tudos/!svn/ver/455/trunk/l4/pkg/dde/linux26/lib/src/fs/buffer.c +END +char_dev.c +K 25 +svn:wc:ra_dav:version-url +V 72 +/repos/tudos/!svn/ver/455/trunk/l4/pkg/dde/linux26/lib/src/fs/char_dev.c +END diff --git a/libdde_linux26/lib/src/fs/.svn/entries b/libdde_linux26/lib/src/fs/.svn/entries new file mode 100644 index 00000000..fa781e75 --- /dev/null +++ b/libdde_linux26/lib/src/fs/.svn/entries @@ -0,0 +1,130 @@ +9 + +dir +465 +http://svn.tudos.org/repos/tudos/trunk/l4/pkg/dde/linux26/lib/src/fs +http://svn.tudos.org/repos/tudos + + + +2009-05-20T14:32:55.606606Z +455 +l4check + + +svn:special svn:externals svn:needs-lock + + + + + + + + + + + +a704ac0b-3a55-4d43-a2a9-7be6f07c34fb + +block_dev.c +file + + + + +2009-11-15T17:17:10.000000Z +eb568fcd29a19e618484d4b5543c680f +2009-05-20T14:32:55.606606Z +455 +l4check + + + + + + + + + + + + + + + + + + + + + +33946 + +buffer.c +file + + + + +2009-11-15T17:17:10.000000Z +4d9f46822ca7a0a24129334ac2d50dd2 +2009-05-20T14:32:55.606606Z +455 +l4check + + + + + + + + + + + + + + + + + + + + + +92122 + +char_dev.c +file + + + + +2009-11-15T17:17:10.000000Z +7dd8da71bba451311d6d91135ae21bf2 +2009-05-20T14:32:55.606606Z +455 +l4check + + + + + + + + + + + + + + + + + + + + + +13672 + diff --git a/libdde_linux26/lib/src/fs/.svn/format b/libdde_linux26/lib/src/fs/.svn/format new file mode 100644 index 00000000..ec635144 --- /dev/null +++ b/libdde_linux26/lib/src/fs/.svn/format @@ -0,0 +1 @@ +9 diff --git a/libdde_linux26/lib/src/fs/.svn/text-base/block_dev.c.svn-base b/libdde_linux26/lib/src/fs/.svn/text-base/block_dev.c.svn-base new file mode 100644 index 00000000..4c4c2f64 --- /dev/null +++ b/libdde_linux26/lib/src/fs/.svn/text-base/block_dev.c.svn-base @@ -0,0 +1,1422 @@ +/* + * linux/fs/block_dev.c + * + * Copyright (C) 1991, 1992 Linus Torvalds + * Copyright (C) 2001 Andrea Arcangeli <andrea@suse.de> SuSE + */ + +#include <linux/init.h> +#include <linux/mm.h> +#include <linux/fcntl.h> +#include <linux/slab.h> +#include <linux/kmod.h> +#include <linux/major.h> +#include <linux/smp_lock.h> +#include <linux/device_cgroup.h> +#include <linux/highmem.h> +#include <linux/blkdev.h> +#include <linux/module.h> +#include <linux/blkpg.h> +#include <linux/buffer_head.h> +#include <linux/writeback.h> +#include <linux/mpage.h> +#include <linux/mount.h> +#include <linux/uio.h> +#include <linux/namei.h> +#include <linux/log2.h> +#include <asm/uaccess.h> +#include "internal.h" + +#ifdef DDE_LINUX +#include "local.h" +#endif + +struct bdev_inode { + struct block_device bdev; + struct inode vfs_inode; +}; + +static const struct address_space_operations def_blk_aops; + +static inline struct bdev_inode *BDEV_I(struct inode *inode) +{ + return container_of(inode, struct bdev_inode, vfs_inode); +} + +inline struct block_device *I_BDEV(struct inode *inode) +{ + return &BDEV_I(inode)->bdev; +} + +EXPORT_SYMBOL(I_BDEV); + +static sector_t max_block(struct block_device *bdev) +{ + sector_t retval = ~((sector_t)0); + loff_t sz = i_size_read(bdev->bd_inode); + + if (sz) { + unsigned int size = block_size(bdev); + unsigned int sizebits = blksize_bits(size); + retval = (sz >> sizebits); + } + return retval; +} + +/* Kill _all_ buffers and pagecache , dirty or not.. */ +static void kill_bdev(struct block_device *bdev) +{ + if (bdev->bd_inode->i_mapping->nrpages == 0) + return; + invalidate_bh_lrus(); + truncate_inode_pages(bdev->bd_inode->i_mapping, 0); +} + +int set_blocksize(struct block_device *bdev, int size) +{ + /* Size must be a power of two, and between 512 and PAGE_SIZE */ + if (size > PAGE_SIZE || size < 512 || !is_power_of_2(size)) + return -EINVAL; + + /* Size cannot be smaller than the size supported by the device */ + if (size < bdev_hardsect_size(bdev)) + return -EINVAL; + + /* Don't change the size if it is same as current */ + if (bdev->bd_block_size != size) { + sync_blockdev(bdev); + bdev->bd_block_size = size; + bdev->bd_inode->i_blkbits = blksize_bits(size); + kill_bdev(bdev); + } + return 0; +} + +EXPORT_SYMBOL(set_blocksize); + +int sb_set_blocksize(struct super_block *sb, int size) +{ + if (set_blocksize(sb->s_bdev, size)) + return 0; + /* If we get here, we know size is power of two + * and it's value is between 512 and PAGE_SIZE */ + sb->s_blocksize = size; + sb->s_blocksize_bits = blksize_bits(size); + return sb->s_blocksize; +} + +EXPORT_SYMBOL(sb_set_blocksize); + +int sb_min_blocksize(struct super_block *sb, int size) +{ + int minsize = bdev_hardsect_size(sb->s_bdev); + if (size < minsize) + size = minsize; + return sb_set_blocksize(sb, size); +} + +EXPORT_SYMBOL(sb_min_blocksize); + +static int +blkdev_get_block(struct inode *inode, sector_t iblock, + struct buffer_head *bh, int create) +{ + if (iblock >= max_block(I_BDEV(inode))) { + if (create) + return -EIO; + + /* + * for reads, we're just trying to fill a partial page. + * return a hole, they will have to call get_block again + * before they can fill it, and they will get -EIO at that + * time + */ + return 0; + } + bh->b_bdev = I_BDEV(inode); + bh->b_blocknr = iblock; + set_buffer_mapped(bh); + return 0; +} + +static int +blkdev_get_blocks(struct inode *inode, sector_t iblock, + struct buffer_head *bh, int create) +{ + sector_t end_block = max_block(I_BDEV(inode)); + unsigned long max_blocks = bh->b_size >> inode->i_blkbits; + + if ((iblock + max_blocks) > end_block) { + max_blocks = end_block - iblock; + if ((long)max_blocks <= 0) { + if (create) + return -EIO; /* write fully beyond EOF */ + /* + * It is a read which is fully beyond EOF. We return + * a !buffer_mapped buffer + */ + max_blocks = 0; + } + } + + bh->b_bdev = I_BDEV(inode); + bh->b_blocknr = iblock; + bh->b_size = max_blocks << inode->i_blkbits; + if (max_blocks) + set_buffer_mapped(bh); + return 0; +} + +static ssize_t +blkdev_direct_IO(int rw, struct kiocb *iocb, const struct iovec *iov, + loff_t offset, unsigned long nr_segs) +{ + struct file *file = iocb->ki_filp; + struct inode *inode = file->f_mapping->host; + +#ifndef DDE_LINUX + return blockdev_direct_IO_no_locking(rw, iocb, inode, I_BDEV(inode), + iov, offset, nr_segs, blkdev_get_blocks, NULL); +#else + WARN_UNIMPL; + return 0; +#endif /* DDE_LINUX */ +} + +static int blkdev_writepage(struct page *page, struct writeback_control *wbc) +{ + return block_write_full_page(page, blkdev_get_block, wbc); +} + +static int blkdev_readpage(struct file * file, struct page * page) +{ + return block_read_full_page(page, blkdev_get_block); +} + +static int blkdev_write_begin(struct file *file, struct address_space *mapping, + loff_t pos, unsigned len, unsigned flags, + struct page **pagep, void **fsdata) +{ + *pagep = NULL; + return block_write_begin(file, mapping, pos, len, flags, pagep, fsdata, + blkdev_get_block); +} + +static int blkdev_write_end(struct file *file, struct address_space *mapping, + loff_t pos, unsigned len, unsigned copied, + struct page *page, void *fsdata) +{ + int ret; + ret = block_write_end(file, mapping, pos, len, copied, page, fsdata); + + unlock_page(page); + page_cache_release(page); + + return ret; +} + +/* + * private llseek: + * for a block special file file->f_path.dentry->d_inode->i_size is zero + * so we compute the size by hand (just as in block_read/write above) + */ +static loff_t block_llseek(struct file *file, loff_t offset, int origin) +{ + struct inode *bd_inode = file->f_mapping->host; + loff_t size; + loff_t retval; + + mutex_lock(&bd_inode->i_mutex); + size = i_size_read(bd_inode); + + switch (origin) { + case 2: + offset += size; + break; + case 1: + offset += file->f_pos; + } + retval = -EINVAL; + if (offset >= 0 && offset <= size) { + if (offset != file->f_pos) { + file->f_pos = offset; + } + retval = offset; + } + mutex_unlock(&bd_inode->i_mutex); + return retval; +} + +/* + * Filp is never NULL; the only case when ->fsync() is called with + * NULL first argument is nfsd_sync_dir() and that's not a directory. + */ + +static int block_fsync(struct file *filp, struct dentry *dentry, int datasync) +{ + return sync_blockdev(I_BDEV(filp->f_mapping->host)); +} + +/* + * pseudo-fs + */ + +static __cacheline_aligned_in_smp DEFINE_SPINLOCK(bdev_lock); +static struct kmem_cache * bdev_cachep __read_mostly; + +static struct inode *bdev_alloc_inode(struct super_block *sb) +{ + struct bdev_inode *ei = kmem_cache_alloc(bdev_cachep, GFP_KERNEL); + if (!ei) + return NULL; + return &ei->vfs_inode; +} + +static void bdev_destroy_inode(struct inode *inode) +{ + struct bdev_inode *bdi = BDEV_I(inode); + + bdi->bdev.bd_inode_backing_dev_info = NULL; + kmem_cache_free(bdev_cachep, bdi); +} + +static void init_once(void *foo) +{ + struct bdev_inode *ei = (struct bdev_inode *) foo; + struct block_device *bdev = &ei->bdev; + + memset(bdev, 0, sizeof(*bdev)); + mutex_init(&bdev->bd_mutex); + sema_init(&bdev->bd_mount_sem, 1); + INIT_LIST_HEAD(&bdev->bd_inodes); + INIT_LIST_HEAD(&bdev->bd_list); +#ifdef CONFIG_SYSFS + INIT_LIST_HEAD(&bdev->bd_holder_list); +#endif + inode_init_once(&ei->vfs_inode); + /* Initialize mutex for freeze. */ + mutex_init(&bdev->bd_fsfreeze_mutex); +} + +static inline void __bd_forget(struct inode *inode) +{ + list_del_init(&inode->i_devices); + inode->i_bdev = NULL; + inode->i_mapping = &inode->i_data; +} + +static void bdev_clear_inode(struct inode *inode) +{ + struct block_device *bdev = &BDEV_I(inode)->bdev; + struct list_head *p; + spin_lock(&bdev_lock); + while ( (p = bdev->bd_inodes.next) != &bdev->bd_inodes ) { + __bd_forget(list_entry(p, struct inode, i_devices)); + } + list_del_init(&bdev->bd_list); + spin_unlock(&bdev_lock); +} + +static const struct super_operations bdev_sops = { + .statfs = simple_statfs, + .alloc_inode = bdev_alloc_inode, + .destroy_inode = bdev_destroy_inode, + .drop_inode = generic_delete_inode, + .clear_inode = bdev_clear_inode, +}; + +static int bd_get_sb(struct file_system_type *fs_type, + int flags, const char *dev_name, void *data, struct vfsmount *mnt) +{ + return get_sb_pseudo(fs_type, "bdev:", &bdev_sops, 0x62646576, mnt); +} + +static struct file_system_type bd_type = { + .name = "bdev", + .get_sb = bd_get_sb, + .kill_sb = kill_anon_super, +}; + +struct super_block *blockdev_superblock __read_mostly; + +void __init bdev_cache_init(void) +{ + int err; + struct vfsmount *bd_mnt; + + bdev_cachep = kmem_cache_create("bdev_cache", sizeof(struct bdev_inode), + 0, (SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT| + SLAB_MEM_SPREAD|SLAB_PANIC), + init_once); + err = register_filesystem(&bd_type); + if (err) + panic("Cannot register bdev pseudo-fs"); + bd_mnt = kern_mount(&bd_type); + if (IS_ERR(bd_mnt)) + panic("Cannot create bdev pseudo-fs"); + blockdev_superblock = bd_mnt->mnt_sb; /* For writeback */ +} + +/* + * Most likely _very_ bad one - but then it's hardly critical for small + * /dev and can be fixed when somebody will need really large one. + * Keep in mind that it will be fed through icache hash function too. + */ +static inline unsigned long hash(dev_t dev) +{ + return MAJOR(dev)+MINOR(dev); +} + +static int bdev_test(struct inode *inode, void *data) +{ + return BDEV_I(inode)->bdev.bd_dev == *(dev_t *)data; +} + +static int bdev_set(struct inode *inode, void *data) +{ + BDEV_I(inode)->bdev.bd_dev = *(dev_t *)data; + return 0; +} + +static LIST_HEAD(all_bdevs); + +struct block_device *bdget(dev_t dev) +{ + struct block_device *bdev; + struct inode *inode; + + printk_all_partitions(); + + inode = iget5_locked(blockdev_superblock, hash(dev), + bdev_test, bdev_set, &dev); + + if (!inode) + return NULL; + + bdev = &BDEV_I(inode)->bdev; + + if (inode->i_state & I_NEW) { + bdev->bd_contains = NULL; + bdev->bd_inode = inode; + bdev->bd_block_size = (1 << inode->i_blkbits); + bdev->bd_part_count = 0; + bdev->bd_invalidated = 0; + inode->i_mode = S_IFBLK; + inode->i_rdev = dev; + inode->i_bdev = bdev; + inode->i_data.a_ops = &def_blk_aops; + mapping_set_gfp_mask(&inode->i_data, GFP_USER); + inode->i_data.backing_dev_info = &default_backing_dev_info; + spin_lock(&bdev_lock); + list_add(&bdev->bd_list, &all_bdevs); + spin_unlock(&bdev_lock); + unlock_new_inode(inode); + } + return bdev; +} + +EXPORT_SYMBOL(bdget); + +long nr_blockdev_pages(void) +{ + struct block_device *bdev; + long ret = 0; + spin_lock(&bdev_lock); + list_for_each_entry(bdev, &all_bdevs, bd_list) { + ret += bdev->bd_inode->i_mapping->nrpages; + } + spin_unlock(&bdev_lock); + return ret; +} + +void bdput(struct block_device *bdev) +{ + iput(bdev->bd_inode); +} + +EXPORT_SYMBOL(bdput); + +static struct block_device *bd_acquire(struct inode *inode) +{ + struct block_device *bdev; + + spin_lock(&bdev_lock); + bdev = inode->i_bdev; + if (bdev) { + atomic_inc(&bdev->bd_inode->i_count); + spin_unlock(&bdev_lock); + return bdev; + } + spin_unlock(&bdev_lock); + + bdev = bdget(inode->i_rdev); + if (bdev) { + spin_lock(&bdev_lock); + if (!inode->i_bdev) { + /* + * We take an additional bd_inode->i_count for inode, + * and it's released in clear_inode() of inode. + * So, we can access it via ->i_mapping always + * without igrab(). + */ + atomic_inc(&bdev->bd_inode->i_count); + inode->i_bdev = bdev; + inode->i_mapping = bdev->bd_inode->i_mapping; + list_add(&inode->i_devices, &bdev->bd_inodes); + } + spin_unlock(&bdev_lock); + } + return bdev; +} + +/* Call when you free inode */ + +void bd_forget(struct inode *inode) +{ + struct block_device *bdev = NULL; + + spin_lock(&bdev_lock); + if (inode->i_bdev) { + if (!sb_is_blkdev_sb(inode->i_sb)) + bdev = inode->i_bdev; + __bd_forget(inode); + } + spin_unlock(&bdev_lock); + + if (bdev) + iput(bdev->bd_inode); +} + +int bd_claim(struct block_device *bdev, void *holder) +{ + int res; + spin_lock(&bdev_lock); + + /* first decide result */ + if (bdev->bd_holder == holder) + res = 0; /* already a holder */ + else if (bdev->bd_holder != NULL) + res = -EBUSY; /* held by someone else */ + else if (bdev->bd_contains == bdev) + res = 0; /* is a whole device which isn't held */ + + else if (bdev->bd_contains->bd_holder == bd_claim) + res = 0; /* is a partition of a device that is being partitioned */ + else if (bdev->bd_contains->bd_holder != NULL) + res = -EBUSY; /* is a partition of a held device */ + else + res = 0; /* is a partition of an un-held device */ + + /* now impose change */ + if (res==0) { + /* note that for a whole device bd_holders + * will be incremented twice, and bd_holder will + * be set to bd_claim before being set to holder + */ + bdev->bd_contains->bd_holders ++; + bdev->bd_contains->bd_holder = bd_claim; + bdev->bd_holders++; + bdev->bd_holder = holder; + } + spin_unlock(&bdev_lock); + return res; +} + +EXPORT_SYMBOL(bd_claim); + +void bd_release(struct block_device *bdev) +{ + spin_lock(&bdev_lock); + if (!--bdev->bd_contains->bd_holders) + bdev->bd_contains->bd_holder = NULL; + if (!--bdev->bd_holders) + bdev->bd_holder = NULL; + spin_unlock(&bdev_lock); +} + +EXPORT_SYMBOL(bd_release); + +#ifdef CONFIG_SYSFS +/* + * Functions for bd_claim_by_kobject / bd_release_from_kobject + * + * If a kobject is passed to bd_claim_by_kobject() + * and the kobject has a parent directory, + * following symlinks are created: + * o from the kobject to the claimed bdev + * o from "holders" directory of the bdev to the parent of the kobject + * bd_release_from_kobject() removes these symlinks. + * + * Example: + * If /dev/dm-0 maps to /dev/sda, kobject corresponding to + * /sys/block/dm-0/slaves is passed to bd_claim_by_kobject(), then: + * /sys/block/dm-0/slaves/sda --> /sys/block/sda + * /sys/block/sda/holders/dm-0 --> /sys/block/dm-0 + */ + +static int add_symlink(struct kobject *from, struct kobject *to) +{ + if (!from || !to) + return 0; + return sysfs_create_link(from, to, kobject_name(to)); +} + +static void del_symlink(struct kobject *from, struct kobject *to) +{ + if (!from || !to) + return; + sysfs_remove_link(from, kobject_name(to)); +} + +/* + * 'struct bd_holder' contains pointers to kobjects symlinked by + * bd_claim_by_kobject. + * It's connected to bd_holder_list which is protected by bdev->bd_sem. + */ +struct bd_holder { + struct list_head list; /* chain of holders of the bdev */ + int count; /* references from the holder */ + struct kobject *sdir; /* holder object, e.g. "/block/dm-0/slaves" */ + struct kobject *hdev; /* e.g. "/block/dm-0" */ + struct kobject *hdir; /* e.g. "/block/sda/holders" */ + struct kobject *sdev; /* e.g. "/block/sda" */ +}; + +/* + * Get references of related kobjects at once. + * Returns 1 on success. 0 on failure. + * + * Should call bd_holder_release_dirs() after successful use. + */ +static int bd_holder_grab_dirs(struct block_device *bdev, + struct bd_holder *bo) +{ + if (!bdev || !bo) + return 0; + + bo->sdir = kobject_get(bo->sdir); + if (!bo->sdir) + return 0; + + bo->hdev = kobject_get(bo->sdir->parent); + if (!bo->hdev) + goto fail_put_sdir; + + bo->sdev = kobject_get(&part_to_dev(bdev->bd_part)->kobj); + if (!bo->sdev) + goto fail_put_hdev; + + bo->hdir = kobject_get(bdev->bd_part->holder_dir); + if (!bo->hdir) + goto fail_put_sdev; + + return 1; + +fail_put_sdev: + kobject_put(bo->sdev); +fail_put_hdev: + kobject_put(bo->hdev); +fail_put_sdir: + kobject_put(bo->sdir); + + return 0; +} + +/* Put references of related kobjects at once. */ +static void bd_holder_release_dirs(struct bd_holder *bo) +{ + kobject_put(bo->hdir); + kobject_put(bo->sdev); + kobject_put(bo->hdev); + kobject_put(bo->sdir); +} + +static struct bd_holder *alloc_bd_holder(struct kobject *kobj) +{ + struct bd_holder *bo; + + bo = kzalloc(sizeof(*bo), GFP_KERNEL); + if (!bo) + return NULL; + + bo->count = 1; + bo->sdir = kobj; + + return bo; +} + +static void free_bd_holder(struct bd_holder *bo) +{ + kfree(bo); +} + +/** + * find_bd_holder - find matching struct bd_holder from the block device + * + * @bdev: struct block device to be searched + * @bo: target struct bd_holder + * + * Returns matching entry with @bo in @bdev->bd_holder_list. + * If found, increment the reference count and return the pointer. + * If not found, returns NULL. + */ +static struct bd_holder *find_bd_holder(struct block_device *bdev, + struct bd_holder *bo) +{ + struct bd_holder *tmp; + + list_for_each_entry(tmp, &bdev->bd_holder_list, list) + if (tmp->sdir == bo->sdir) { + tmp->count++; + return tmp; + } + + return NULL; +} + +/** + * add_bd_holder - create sysfs symlinks for bd_claim() relationship + * + * @bdev: block device to be bd_claimed + * @bo: preallocated and initialized by alloc_bd_holder() + * + * Add @bo to @bdev->bd_holder_list, create symlinks. + * + * Returns 0 if symlinks are created. + * Returns -ve if something fails. + */ +static int add_bd_holder(struct block_device *bdev, struct bd_holder *bo) +{ + int err; + + if (!bo) + return -EINVAL; + + if (!bd_holder_grab_dirs(bdev, bo)) + return -EBUSY; + + err = add_symlink(bo->sdir, bo->sdev); + if (err) + return err; + + err = add_symlink(bo->hdir, bo->hdev); + if (err) { + del_symlink(bo->sdir, bo->sdev); + return err; + } + + list_add_tail(&bo->list, &bdev->bd_holder_list); + return 0; +} + +/** + * del_bd_holder - delete sysfs symlinks for bd_claim() relationship + * + * @bdev: block device to be bd_claimed + * @kobj: holder's kobject + * + * If there is matching entry with @kobj in @bdev->bd_holder_list + * and no other bd_claim() from the same kobject, + * remove the struct bd_holder from the list, delete symlinks for it. + * + * Returns a pointer to the struct bd_holder when it's removed from the list + * and ready to be freed. + * Returns NULL if matching claim isn't found or there is other bd_claim() + * by the same kobject. + */ +static struct bd_holder *del_bd_holder(struct block_device *bdev, + struct kobject *kobj) +{ + struct bd_holder *bo; + + list_for_each_entry(bo, &bdev->bd_holder_list, list) { + if (bo->sdir == kobj) { + bo->count--; + BUG_ON(bo->count < 0); + if (!bo->count) { + list_del(&bo->list); + del_symlink(bo->sdir, bo->sdev); + del_symlink(bo->hdir, bo->hdev); + bd_holder_release_dirs(bo); + return bo; + } + break; + } + } + + return NULL; +} + +/** + * bd_claim_by_kobject - bd_claim() with additional kobject signature + * + * @bdev: block device to be claimed + * @holder: holder's signature + * @kobj: holder's kobject + * + * Do bd_claim() and if it succeeds, create sysfs symlinks between + * the bdev and the holder's kobject. + * Use bd_release_from_kobject() when relesing the claimed bdev. + * + * Returns 0 on success. (same as bd_claim()) + * Returns errno on failure. + */ +static int bd_claim_by_kobject(struct block_device *bdev, void *holder, + struct kobject *kobj) +{ + int err; + struct bd_holder *bo, *found; + + if (!kobj) + return -EINVAL; + + bo = alloc_bd_holder(kobj); + if (!bo) + return -ENOMEM; + + mutex_lock(&bdev->bd_mutex); + + err = bd_claim(bdev, holder); + if (err) + goto fail; + + found = find_bd_holder(bdev, bo); + if (found) + goto fail; + + err = add_bd_holder(bdev, bo); + if (err) + bd_release(bdev); + else + bo = NULL; +fail: + mutex_unlock(&bdev->bd_mutex); + free_bd_holder(bo); + return err; +} + +/** + * bd_release_from_kobject - bd_release() with additional kobject signature + * + * @bdev: block device to be released + * @kobj: holder's kobject + * + * Do bd_release() and remove sysfs symlinks created by bd_claim_by_kobject(). + */ +static void bd_release_from_kobject(struct block_device *bdev, + struct kobject *kobj) +{ + if (!kobj) + return; + + mutex_lock(&bdev->bd_mutex); + bd_release(bdev); + free_bd_holder(del_bd_holder(bdev, kobj)); + mutex_unlock(&bdev->bd_mutex); +} + +/** + * bd_claim_by_disk - wrapper function for bd_claim_by_kobject() + * + * @bdev: block device to be claimed + * @holder: holder's signature + * @disk: holder's gendisk + * + * Call bd_claim_by_kobject() with getting @disk->slave_dir. + */ +int bd_claim_by_disk(struct block_device *bdev, void *holder, + struct gendisk *disk) +{ + return bd_claim_by_kobject(bdev, holder, kobject_get(disk->slave_dir)); +} +EXPORT_SYMBOL_GPL(bd_claim_by_disk); + +/** + * bd_release_from_disk - wrapper function for bd_release_from_kobject() + * + * @bdev: block device to be claimed + * @disk: holder's gendisk + * + * Call bd_release_from_kobject() and put @disk->slave_dir. + */ +void bd_release_from_disk(struct block_device *bdev, struct gendisk *disk) +{ + bd_release_from_kobject(bdev, disk->slave_dir); + kobject_put(disk->slave_dir); +} +EXPORT_SYMBOL_GPL(bd_release_from_disk); +#endif + +/* + * Tries to open block device by device number. Use it ONLY if you + * really do not have anything better - i.e. when you are behind a + * truly sucky interface and all you are given is a device number. _Never_ + * to be used for internal purposes. If you ever need it - reconsider + * your API. + */ +struct block_device *open_by_devnum(dev_t dev, fmode_t mode) +{ + struct block_device *bdev = bdget(dev); + int err = -ENOMEM; + if (bdev) + err = blkdev_get(bdev, mode); + return err ? ERR_PTR(err) : bdev; +} + +EXPORT_SYMBOL(open_by_devnum); + +/** + * flush_disk - invalidates all buffer-cache entries on a disk + * + * @bdev: struct block device to be flushed + * + * Invalidates all buffer-cache entries on a disk. It should be called + * when a disk has been changed -- either by a media change or online + * resize. + */ +static void flush_disk(struct block_device *bdev) +{ + if (__invalidate_device(bdev)) { + char name[BDEVNAME_SIZE] = ""; + + if (bdev->bd_disk) + disk_name(bdev->bd_disk, 0, name); + printk(KERN_WARNING "VFS: busy inodes on changed media or " + "resized disk %s\n", name); + } + + if (!bdev->bd_disk) + return; + if (disk_partitionable(bdev->bd_disk)) + bdev->bd_invalidated = 1; +} + +/** + * check_disk_size_change - checks for disk size change and adjusts bdev size. + * @disk: struct gendisk to check + * @bdev: struct bdev to adjust. + * + * This routine checks to see if the bdev size does not match the disk size + * and adjusts it if it differs. + */ +void check_disk_size_change(struct gendisk *disk, struct block_device *bdev) +{ + loff_t disk_size, bdev_size; + + disk_size = (loff_t)get_capacity(disk) << 9; + bdev_size = i_size_read(bdev->bd_inode); + if (disk_size != bdev_size) { + char name[BDEVNAME_SIZE]; + + disk_name(disk, 0, name); + printk(KERN_INFO + "%s: detected capacity change from %lld to %lld\n", + name, bdev_size, disk_size); + i_size_write(bdev->bd_inode, disk_size); + flush_disk(bdev); + } +} +EXPORT_SYMBOL(check_disk_size_change); + +/** + * revalidate_disk - wrapper for lower-level driver's revalidate_disk call-back + * @disk: struct gendisk to be revalidated + * + * This routine is a wrapper for lower-level driver's revalidate_disk + * call-backs. It is used to do common pre and post operations needed + * for all revalidate_disk operations. + */ +int revalidate_disk(struct gendisk *disk) +{ + struct block_device *bdev; + int ret = 0; + + if (disk->fops->revalidate_disk) + ret = disk->fops->revalidate_disk(disk); + + bdev = bdget_disk(disk, 0); + if (!bdev) + return ret; + + mutex_lock(&bdev->bd_mutex); + check_disk_size_change(disk, bdev); + mutex_unlock(&bdev->bd_mutex); + bdput(bdev); + return ret; +} +EXPORT_SYMBOL(revalidate_disk); + +/* + * This routine checks whether a removable media has been changed, + * and invalidates all buffer-cache-entries in that case. This + * is a relatively slow routine, so we have to try to minimize using + * it. Thus it is called only upon a 'mount' or 'open'. This + * is the best way of combining speed and utility, I think. + * People changing diskettes in the middle of an operation deserve + * to lose :-) + */ +int check_disk_change(struct block_device *bdev) +{ + struct gendisk *disk = bdev->bd_disk; + struct block_device_operations * bdops = disk->fops; + + if (!bdops->media_changed) + return 0; + if (!bdops->media_changed(bdev->bd_disk)) + return 0; + + flush_disk(bdev); + if (bdops->revalidate_disk) + bdops->revalidate_disk(bdev->bd_disk); + return 1; +} + +EXPORT_SYMBOL(check_disk_change); + +void bd_set_size(struct block_device *bdev, loff_t size) +{ + unsigned bsize = bdev_hardsect_size(bdev); + + bdev->bd_inode->i_size = size; + while (bsize < PAGE_CACHE_SIZE) { + if (size & bsize) + break; + bsize <<= 1; + } + bdev->bd_block_size = bsize; + bdev->bd_inode->i_blkbits = blksize_bits(bsize); +} +EXPORT_SYMBOL(bd_set_size); + +static int __blkdev_put(struct block_device *bdev, fmode_t mode, int for_part); + +/* + * bd_mutex locking: + * + * mutex_lock(part->bd_mutex) + * mutex_lock_nested(whole->bd_mutex, 1) + */ + +static int __blkdev_get(struct block_device *bdev, fmode_t mode, int for_part) +{ + struct gendisk *disk; + int ret; + int partno; + int perm = 0; + + if (mode & FMODE_READ) + perm |= MAY_READ; + if (mode & FMODE_WRITE) + perm |= MAY_WRITE; + /* + * hooks: /n/, see "layering violations". + */ + ret = devcgroup_inode_permission(bdev->bd_inode, perm); + if (ret != 0) { + bdput(bdev); + return ret; + } + + lock_kernel(); + restart: + + ret = -ENXIO; + disk = get_gendisk(bdev->bd_dev, &partno); + if (!disk) + goto out_unlock_kernel; + + mutex_lock_nested(&bdev->bd_mutex, for_part); + if (!bdev->bd_openers) { + bdev->bd_disk = disk; + bdev->bd_contains = bdev; + if (!partno) { + struct backing_dev_info *bdi; + + ret = -ENXIO; + bdev->bd_part = disk_get_part(disk, partno); + if (!bdev->bd_part) + goto out_clear; + + if (disk->fops->open) { + ret = disk->fops->open(bdev, mode); + if (ret == -ERESTARTSYS) { + /* Lost a race with 'disk' being + * deleted, try again. + * See md.c + */ + disk_put_part(bdev->bd_part); + bdev->bd_part = NULL; + module_put(disk->fops->owner); + put_disk(disk); + bdev->bd_disk = NULL; + mutex_unlock(&bdev->bd_mutex); + goto restart; + } + if (ret) + goto out_clear; + } + if (!bdev->bd_openers) { + bd_set_size(bdev,(loff_t)get_capacity(disk)<<9); + bdi = blk_get_backing_dev_info(bdev); + if (bdi == NULL) + bdi = &default_backing_dev_info; + bdev->bd_inode->i_data.backing_dev_info = bdi; + } + if (bdev->bd_invalidated) + rescan_partitions(disk, bdev); + } else { + struct block_device *whole; + whole = bdget_disk(disk, 0); + ret = -ENOMEM; + if (!whole) + goto out_clear; + BUG_ON(for_part); + ret = __blkdev_get(whole, mode, 1); + if (ret) + goto out_clear; + bdev->bd_contains = whole; + bdev->bd_inode->i_data.backing_dev_info = + whole->bd_inode->i_data.backing_dev_info; + bdev->bd_part = disk_get_part(disk, partno); + if (!(disk->flags & GENHD_FL_UP) || + !bdev->bd_part || !bdev->bd_part->nr_sects) { + ret = -ENXIO; + goto out_clear; + } + bd_set_size(bdev, (loff_t)bdev->bd_part->nr_sects << 9); + } + } else { + put_disk(disk); + module_put(disk->fops->owner); + disk = NULL; + if (bdev->bd_contains == bdev) { + if (bdev->bd_disk->fops->open) { + ret = bdev->bd_disk->fops->open(bdev, mode); + if (ret) + goto out_unlock_bdev; + } + if (bdev->bd_invalidated) + rescan_partitions(bdev->bd_disk, bdev); + } + } + bdev->bd_openers++; + if (for_part) + bdev->bd_part_count++; + mutex_unlock(&bdev->bd_mutex); + unlock_kernel(); + return 0; + + out_clear: + disk_put_part(bdev->bd_part); + bdev->bd_disk = NULL; + bdev->bd_part = NULL; + bdev->bd_inode->i_data.backing_dev_info = &default_backing_dev_info; + if (bdev != bdev->bd_contains) + __blkdev_put(bdev->bd_contains, mode, 1); + bdev->bd_contains = NULL; + out_unlock_bdev: + mutex_unlock(&bdev->bd_mutex); + out_unlock_kernel: + unlock_kernel(); + + if (disk) + module_put(disk->fops->owner); + put_disk(disk); + bdput(bdev); + + return ret; +} + +int blkdev_get(struct block_device *bdev, fmode_t mode) +{ + return __blkdev_get(bdev, mode, 0); +} +EXPORT_SYMBOL(blkdev_get); + +static int blkdev_open(struct inode * inode, struct file * filp) +{ + struct block_device *bdev; + int res; + + /* + * Preserve backwards compatibility and allow large file access + * even if userspace doesn't ask for it explicitly. Some mkfs + * binary needs it. We might want to drop this workaround + * during an unstable branch. + */ + filp->f_flags |= O_LARGEFILE; + + if (filp->f_flags & O_NDELAY) + filp->f_mode |= FMODE_NDELAY; + if (filp->f_flags & O_EXCL) + filp->f_mode |= FMODE_EXCL; + if ((filp->f_flags & O_ACCMODE) == 3) + filp->f_mode |= FMODE_WRITE_IOCTL; + + bdev = bd_acquire(inode); + if (bdev == NULL) + return -ENOMEM; + + filp->f_mapping = bdev->bd_inode->i_mapping; + + res = blkdev_get(bdev, filp->f_mode); + if (res) + return res; + + if (filp->f_mode & FMODE_EXCL) { + res = bd_claim(bdev, filp); + if (res) + goto out_blkdev_put; + } + + return 0; + + out_blkdev_put: + blkdev_put(bdev, filp->f_mode); + return res; +} + +static int __blkdev_put(struct block_device *bdev, fmode_t mode, int for_part) +{ + int ret = 0; + struct gendisk *disk = bdev->bd_disk; + struct block_device *victim = NULL; + + mutex_lock_nested(&bdev->bd_mutex, for_part); + lock_kernel(); + if (for_part) + bdev->bd_part_count--; + + if (!--bdev->bd_openers) { + sync_blockdev(bdev); + kill_bdev(bdev); + } + if (bdev->bd_contains == bdev) { + if (disk->fops->release) + ret = disk->fops->release(disk, mode); + } + if (!bdev->bd_openers) { + struct module *owner = disk->fops->owner; + + put_disk(disk); + module_put(owner); + disk_put_part(bdev->bd_part); + bdev->bd_part = NULL; + bdev->bd_disk = NULL; + bdev->bd_inode->i_data.backing_dev_info = &default_backing_dev_info; + if (bdev != bdev->bd_contains) + victim = bdev->bd_contains; + bdev->bd_contains = NULL; + } + unlock_kernel(); + mutex_unlock(&bdev->bd_mutex); + bdput(bdev); + if (victim) + __blkdev_put(victim, mode, 1); + return ret; +} + +int blkdev_put(struct block_device *bdev, fmode_t mode) +{ + return __blkdev_put(bdev, mode, 0); +} +EXPORT_SYMBOL(blkdev_put); + +static int blkdev_close(struct inode * inode, struct file * filp) +{ + struct block_device *bdev = I_BDEV(filp->f_mapping->host); + if (bdev->bd_holder == filp) + bd_release(bdev); + return blkdev_put(bdev, filp->f_mode); +} + +static long block_ioctl(struct file *file, unsigned cmd, unsigned long arg) +{ + struct block_device *bdev = I_BDEV(file->f_mapping->host); + fmode_t mode = file->f_mode; + + /* + * O_NDELAY can be altered using fcntl(.., F_SETFL, ..), so we have + * to updated it before every ioctl. + */ + if (file->f_flags & O_NDELAY) + mode |= FMODE_NDELAY; + else + mode &= ~FMODE_NDELAY; + + return blkdev_ioctl(bdev, mode, cmd, arg); +} + +/* + * Try to release a page associated with block device when the system + * is under memory pressure. + */ +static int blkdev_releasepage(struct page *page, gfp_t wait) +{ + struct super_block *super = BDEV_I(page->mapping->host)->bdev.bd_super; + + if (super && super->s_op->bdev_try_to_free_page) + return super->s_op->bdev_try_to_free_page(super, page, wait); + + return try_to_free_buffers(page); +} + +static const struct address_space_operations def_blk_aops = { + .readpage = blkdev_readpage, + .writepage = blkdev_writepage, + .sync_page = block_sync_page, + .write_begin = blkdev_write_begin, + .write_end = blkdev_write_end, + .writepages = generic_writepages, + .releasepage = blkdev_releasepage, + .direct_IO = blkdev_direct_IO, +}; + +const struct file_operations def_blk_fops = { + .open = blkdev_open, + .release = blkdev_close, +#ifndef DDE_LINUX + .llseek = block_llseek, + .read = do_sync_read, + .write = do_sync_write, + .aio_read = generic_file_aio_read, + .aio_write = generic_file_aio_write_nolock, + .mmap = generic_file_mmap, + .fsync = block_fsync, + .unlocked_ioctl = block_ioctl, +#ifdef CONFIG_COMPAT + .compat_ioctl = compat_blkdev_ioctl, +#endif + .splice_read = generic_file_splice_read, + .splice_write = generic_file_splice_write, +#endif /* DDE_LINUX */ +}; + +int ioctl_by_bdev(struct block_device *bdev, unsigned cmd, unsigned long arg) +{ + int res; + mm_segment_t old_fs = get_fs(); + set_fs(KERNEL_DS); + res = blkdev_ioctl(bdev, 0, cmd, arg); + set_fs(old_fs); + return res; +} + +EXPORT_SYMBOL(ioctl_by_bdev); + +/** + * lookup_bdev - lookup a struct block_device by name + * @pathname: special file representing the block device + * + * Get a reference to the blockdevice at @pathname in the current + * namespace if possible and return it. Return ERR_PTR(error) + * otherwise. + */ +struct block_device *lookup_bdev(const char *pathname) +{ + struct block_device *bdev; + struct inode *inode; + struct path path; + int error; + + if (!pathname || !*pathname) + return ERR_PTR(-EINVAL); + + error = kern_path(pathname, LOOKUP_FOLLOW, &path); + if (error) + return ERR_PTR(error); + + inode = path.dentry->d_inode; + error = -ENOTBLK; + if (!S_ISBLK(inode->i_mode)) + goto fail; + error = -EACCES; + if (path.mnt->mnt_flags & MNT_NODEV) + goto fail; + error = -ENOMEM; + bdev = bd_acquire(inode); + if (!bdev) + goto fail; +out: + path_put(&path); + return bdev; +fail: + bdev = ERR_PTR(error); + goto out; +} +EXPORT_SYMBOL(lookup_bdev); + +/** + * open_bdev_exclusive - open a block device by name and set it up for use + * + * @path: special file representing the block device + * @mode: FMODE_... combination to pass be used + * @holder: owner for exclusion + * + * Open the blockdevice described by the special file at @path, claim it + * for the @holder. + */ +struct block_device *open_bdev_exclusive(const char *path, fmode_t mode, void *holder) +{ + struct block_device *bdev; + int error = 0; + + bdev = lookup_bdev(path); + if (IS_ERR(bdev)) + return bdev; + + error = blkdev_get(bdev, mode); + if (error) + return ERR_PTR(error); + error = -EACCES; + if ((mode & FMODE_WRITE) && bdev_read_only(bdev)) + goto blkdev_put; + error = bd_claim(bdev, holder); + if (error) + goto blkdev_put; + + return bdev; + +blkdev_put: + blkdev_put(bdev, mode); + return ERR_PTR(error); +} + +EXPORT_SYMBOL(open_bdev_exclusive); + +/** + * close_bdev_exclusive - close a blockdevice opened by open_bdev_exclusive() + * + * @bdev: blockdevice to close + * @mode: mode, must match that used to open. + * + * This is the counterpart to open_bdev_exclusive(). + */ +void close_bdev_exclusive(struct block_device *bdev, fmode_t mode) +{ + bd_release(bdev); + blkdev_put(bdev, mode); +} + +EXPORT_SYMBOL(close_bdev_exclusive); + +int __invalidate_device(struct block_device *bdev) +{ + struct super_block *sb = get_super(bdev); + int res = 0; + + if (sb) { + /* + * no need to lock the super, get_super holds the + * read mutex so the filesystem cannot go away + * under us (->put_super runs with the write lock + * hold). + */ + shrink_dcache_sb(sb); + res = invalidate_inodes(sb); + drop_super(sb); + } + invalidate_bdev(bdev); + return res; +} +EXPORT_SYMBOL(__invalidate_device); diff --git a/libdde_linux26/lib/src/fs/.svn/text-base/buffer.c.svn-base b/libdde_linux26/lib/src/fs/.svn/text-base/buffer.c.svn-base new file mode 100644 index 00000000..d3b1c445 --- /dev/null +++ b/libdde_linux26/lib/src/fs/.svn/text-base/buffer.c.svn-base @@ -0,0 +1,3474 @@ +/* + * linux/fs/buffer.c + * + * Copyright (C) 1991, 1992, 2002 Linus Torvalds + */ + +/* + * Start bdflush() with kernel_thread not syscall - Paul Gortmaker, 12/95 + * + * Removed a lot of unnecessary code and simplified things now that + * the buffer cache isn't our primary cache - Andrew Tridgell 12/96 + * + * Speed up hash, lru, and free list operations. Use gfp() for allocating + * hash table, use SLAB cache for buffer heads. SMP threading. -DaveM + * + * Added 32k buffer block sizes - these are required older ARM systems. - RMK + * + * async buffer flushing, 1999 Andrea Arcangeli <andrea@suse.de> + */ + +#include <linux/kernel.h> +#include <linux/syscalls.h> +#include <linux/fs.h> +#include <linux/mm.h> +#include <linux/percpu.h> +#include <linux/slab.h> +#include <linux/capability.h> +#include <linux/blkdev.h> +#include <linux/file.h> +#include <linux/quotaops.h> +#include <linux/highmem.h> +#include <linux/module.h> +#include <linux/writeback.h> +#include <linux/hash.h> +#include <linux/suspend.h> +#include <linux/buffer_head.h> +#include <linux/task_io_accounting_ops.h> +#include <linux/bio.h> +#include <linux/notifier.h> +#include <linux/cpu.h> +#include <linux/bitops.h> +#include <linux/mpage.h> +#include <linux/bit_spinlock.h> + +static int fsync_buffers_list(spinlock_t *lock, struct list_head *list); + +#define BH_ENTRY(list) list_entry((list), struct buffer_head, b_assoc_buffers) + +inline void +init_buffer(struct buffer_head *bh, bh_end_io_t *handler, void *private) +{ + bh->b_end_io = handler; + bh->b_private = private; +} + +static int sync_buffer(void *word) +{ + struct block_device *bd; + struct buffer_head *bh + = container_of(word, struct buffer_head, b_state); + + smp_mb(); + bd = bh->b_bdev; + if (bd) + blk_run_address_space(bd->bd_inode->i_mapping); + io_schedule(); + return 0; +} + +void __lock_buffer(struct buffer_head *bh) +{ + wait_on_bit_lock(&bh->b_state, BH_Lock, sync_buffer, + TASK_UNINTERRUPTIBLE); +} +EXPORT_SYMBOL(__lock_buffer); + +void unlock_buffer(struct buffer_head *bh) +{ + clear_bit_unlock(BH_Lock, &bh->b_state); + smp_mb__after_clear_bit(); + wake_up_bit(&bh->b_state, BH_Lock); +} + +/* + * Block until a buffer comes unlocked. This doesn't stop it + * from becoming locked again - you have to lock it yourself + * if you want to preserve its state. + */ +void __wait_on_buffer(struct buffer_head * bh) +{ + wait_on_bit(&bh->b_state, BH_Lock, sync_buffer, TASK_UNINTERRUPTIBLE); +} + +static void +__clear_page_buffers(struct page *page) +{ + ClearPagePrivate(page); + set_page_private(page, 0); + page_cache_release(page); +} + + +static int quiet_error(struct buffer_head *bh) +{ + if (!test_bit(BH_Quiet, &bh->b_state) && printk_ratelimit()) + return 0; + return 1; +} + + +static void buffer_io_error(struct buffer_head *bh) +{ + char b[BDEVNAME_SIZE]; + printk(KERN_ERR "Buffer I/O error on device %s, logical block %Lu\n", + bdevname(bh->b_bdev, b), + (unsigned long long)bh->b_blocknr); +} + +/* + * End-of-IO handler helper function which does not touch the bh after + * unlocking it. + * Note: unlock_buffer() sort-of does touch the bh after unlocking it, but + * a race there is benign: unlock_buffer() only use the bh's address for + * hashing after unlocking the buffer, so it doesn't actually touch the bh + * itself. + */ +static void __end_buffer_read_notouch(struct buffer_head *bh, int uptodate) +{ + if (uptodate) { + set_buffer_uptodate(bh); + } else { + /* This happens, due to failed READA attempts. */ + clear_buffer_uptodate(bh); + } + unlock_buffer(bh); +} + +/* + * Default synchronous end-of-IO handler.. Just mark it up-to-date and + * unlock the buffer. This is what ll_rw_block uses too. + */ +void end_buffer_read_sync(struct buffer_head *bh, int uptodate) +{ + __end_buffer_read_notouch(bh, uptodate); + put_bh(bh); +} + +void end_buffer_write_sync(struct buffer_head *bh, int uptodate) +{ + char b[BDEVNAME_SIZE]; + + if (uptodate) { + set_buffer_uptodate(bh); + } else { + if (!buffer_eopnotsupp(bh) && !quiet_error(bh)) { + buffer_io_error(bh); + printk(KERN_WARNING "lost page write due to " + "I/O error on %s\n", + bdevname(bh->b_bdev, b)); + } + set_buffer_write_io_error(bh); + clear_buffer_uptodate(bh); + } + unlock_buffer(bh); + put_bh(bh); +} + +/* + * Write out and wait upon all the dirty data associated with a block + * device via its mapping. Does not take the superblock lock. + */ +int sync_blockdev(struct block_device *bdev) +{ +#ifndef DDE_LINUX + int ret = 0; + + if (bdev) + ret = filemap_write_and_wait(bdev->bd_inode->i_mapping); + return ret; +#else + WARN_UNIMPL; + return 0; +#endif /* DDE_LINUX */ +} +EXPORT_SYMBOL(sync_blockdev); + +/* + * Write out and wait upon all dirty data associated with this + * device. Filesystem data as well as the underlying block + * device. Takes the superblock lock. + */ +int fsync_bdev(struct block_device *bdev) +{ +#ifndef DDE_LINUX + struct super_block *sb = get_super(bdev); + if (sb) { + int res = fsync_super(sb); + drop_super(sb); + return res; + } + return sync_blockdev(bdev); +#else + WARN_UNIMPL; + return -1; +#endif +} + +/** + * freeze_bdev -- lock a filesystem and force it into a consistent state + * @bdev: blockdevice to lock + * + * This takes the block device bd_mount_sem to make sure no new mounts + * happen on bdev until thaw_bdev() is called. + * If a superblock is found on this device, we take the s_umount semaphore + * on it to make sure nobody unmounts until the snapshot creation is done. + * The reference counter (bd_fsfreeze_count) guarantees that only the last + * unfreeze process can unfreeze the frozen filesystem actually when multiple + * freeze requests arrive simultaneously. It counts up in freeze_bdev() and + * count down in thaw_bdev(). When it becomes 0, thaw_bdev() will unfreeze + * actually. + */ +struct super_block *freeze_bdev(struct block_device *bdev) +{ + struct super_block *sb; + int error = 0; + + mutex_lock(&bdev->bd_fsfreeze_mutex); + if (bdev->bd_fsfreeze_count > 0) { + bdev->bd_fsfreeze_count++; + sb = get_super(bdev); + mutex_unlock(&bdev->bd_fsfreeze_mutex); + return sb; + } + bdev->bd_fsfreeze_count++; + + down(&bdev->bd_mount_sem); + sb = get_super(bdev); + if (sb && !(sb->s_flags & MS_RDONLY)) { + sb->s_frozen = SB_FREEZE_WRITE; + smp_wmb(); + + __fsync_super(sb); + + sb->s_frozen = SB_FREEZE_TRANS; + smp_wmb(); + + sync_blockdev(sb->s_bdev); + + if (sb->s_op->freeze_fs) { + error = sb->s_op->freeze_fs(sb); + if (error) { + printk(KERN_ERR + "VFS:Filesystem freeze failed\n"); + sb->s_frozen = SB_UNFROZEN; + drop_super(sb); + up(&bdev->bd_mount_sem); + bdev->bd_fsfreeze_count--; + mutex_unlock(&bdev->bd_fsfreeze_mutex); + return ERR_PTR(error); + } + } + } + + sync_blockdev(bdev); + mutex_unlock(&bdev->bd_fsfreeze_mutex); + + return sb; /* thaw_bdev releases s->s_umount and bd_mount_sem */ +} +EXPORT_SYMBOL(freeze_bdev); + +/** + * thaw_bdev -- unlock filesystem + * @bdev: blockdevice to unlock + * @sb: associated superblock + * + * Unlocks the filesystem and marks it writeable again after freeze_bdev(). + */ +int thaw_bdev(struct block_device *bdev, struct super_block *sb) +{ + int error = 0; + + mutex_lock(&bdev->bd_fsfreeze_mutex); + if (!bdev->bd_fsfreeze_count) { + mutex_unlock(&bdev->bd_fsfreeze_mutex); + return -EINVAL; + } + + bdev->bd_fsfreeze_count--; + if (bdev->bd_fsfreeze_count > 0) { + if (sb) + drop_super(sb); + mutex_unlock(&bdev->bd_fsfreeze_mutex); + return 0; + } + + if (sb) { + BUG_ON(sb->s_bdev != bdev); + if (!(sb->s_flags & MS_RDONLY)) { + if (sb->s_op->unfreeze_fs) { + error = sb->s_op->unfreeze_fs(sb); + if (error) { + printk(KERN_ERR + "VFS:Filesystem thaw failed\n"); + sb->s_frozen = SB_FREEZE_TRANS; + bdev->bd_fsfreeze_count++; + mutex_unlock(&bdev->bd_fsfreeze_mutex); + return error; + } + } + sb->s_frozen = SB_UNFROZEN; + smp_wmb(); + wake_up(&sb->s_wait_unfrozen); + } + drop_super(sb); + } + + up(&bdev->bd_mount_sem); + mutex_unlock(&bdev->bd_fsfreeze_mutex); + return 0; +} +EXPORT_SYMBOL(thaw_bdev); + +/* + * Various filesystems appear to want __find_get_block to be non-blocking. + * But it's the page lock which protects the buffers. To get around this, + * we get exclusion from try_to_free_buffers with the blockdev mapping's + * private_lock. + * + * Hack idea: for the blockdev mapping, i_bufferlist_lock contention + * may be quite high. This code could TryLock the page, and if that + * succeeds, there is no need to take private_lock. (But if + * private_lock is contended then so is mapping->tree_lock). + */ +static struct buffer_head * +__find_get_block_slow(struct block_device *bdev, sector_t block) +{ + struct inode *bd_inode = bdev->bd_inode; + struct address_space *bd_mapping = bd_inode->i_mapping; + struct buffer_head *ret = NULL; + pgoff_t index; + struct buffer_head *bh; + struct buffer_head *head; + struct page *page; + int all_mapped = 1; + + index = block >> (PAGE_CACHE_SHIFT - bd_inode->i_blkbits); + page = find_get_page(bd_mapping, index); + if (!page) + goto out; + + spin_lock(&bd_mapping->private_lock); + if (!page_has_buffers(page)) + goto out_unlock; + head = page_buffers(page); + bh = head; + do { + if (bh->b_blocknr == block) { + ret = bh; + get_bh(bh); + goto out_unlock; + } + if (!buffer_mapped(bh)) + all_mapped = 0; + bh = bh->b_this_page; + } while (bh != head); + + /* we might be here because some of the buffers on this page are + * not mapped. This is due to various races between + * file io on the block device and getblk. It gets dealt with + * elsewhere, don't buffer_error if we had some unmapped buffers + */ + if (all_mapped) { + printk("__find_get_block_slow() failed. " + "block=%llu, b_blocknr=%llu\n", + (unsigned long long)block, + (unsigned long long)bh->b_blocknr); + printk("b_state=0x%08lx, b_size=%zu\n", + bh->b_state, bh->b_size); + printk("device blocksize: %d\n", 1 << bd_inode->i_blkbits); + } +out_unlock: + spin_unlock(&bd_mapping->private_lock); + page_cache_release(page); +out: + return ret; +} + +/* If invalidate_buffers() will trash dirty buffers, it means some kind + of fs corruption is going on. Trashing dirty data always imply losing + information that was supposed to be just stored on the physical layer + by the user. + + Thus invalidate_buffers in general usage is not allwowed to trash + dirty buffers. For example ioctl(FLSBLKBUF) expects dirty data to + be preserved. These buffers are simply skipped. + + We also skip buffers which are still in use. For example this can + happen if a userspace program is reading the block device. + + NOTE: In the case where the user removed a removable-media-disk even if + there's still dirty data not synced on disk (due a bug in the device driver + or due an error of the user), by not destroying the dirty buffers we could + generate corruption also on the next media inserted, thus a parameter is + necessary to handle this case in the most safe way possible (trying + to not corrupt also the new disk inserted with the data belonging to + the old now corrupted disk). Also for the ramdisk the natural thing + to do in order to release the ramdisk memory is to destroy dirty buffers. + + These are two special cases. Normal usage imply the device driver + to issue a sync on the device (without waiting I/O completion) and + then an invalidate_buffers call that doesn't trash dirty buffers. + + For handling cache coherency with the blkdev pagecache the 'update' case + is been introduced. It is needed to re-read from disk any pinned + buffer. NOTE: re-reading from disk is destructive so we can do it only + when we assume nobody is changing the buffercache under our I/O and when + we think the disk contains more recent information than the buffercache. + The update == 1 pass marks the buffers we need to update, the update == 2 + pass does the actual I/O. */ +void invalidate_bdev(struct block_device *bdev) +{ + struct address_space *mapping = bdev->bd_inode->i_mapping; + + if (mapping->nrpages == 0) + return; + +#ifndef DDE_LINUX + invalidate_bh_lrus(); + invalidate_mapping_pages(mapping, 0, -1); +#endif +} + +/* + * Kick pdflush then try to free up some ZONE_NORMAL memory. + */ +static void free_more_memory(void) +{ + struct zone *zone; + int nid; + +#ifndef DDE_LINUX + wakeup_pdflush(1024); + yield(); + + for_each_online_node(nid) { + (void)first_zones_zonelist(node_zonelist(nid, GFP_NOFS), + gfp_zone(GFP_NOFS), NULL, + &zone); + if (zone) + try_to_free_pages(node_zonelist(nid, GFP_NOFS), 0, + GFP_NOFS); + } +#else + WARN_UNIMPL; +#endif +} + +/* + * I/O completion handler for block_read_full_page() - pages + * which come unlocked at the end of I/O. + */ +static void end_buffer_async_read(struct buffer_head *bh, int uptodate) +{ + unsigned long flags; + struct buffer_head *first; + struct buffer_head *tmp; + struct page *page; + int page_uptodate = 1; + + BUG_ON(!buffer_async_read(bh)); + + page = bh->b_page; + if (uptodate) { + set_buffer_uptodate(bh); + } else { + clear_buffer_uptodate(bh); + if (!quiet_error(bh)) + buffer_io_error(bh); + SetPageError(page); + } + + /* + * Be _very_ careful from here on. Bad things can happen if + * two buffer heads end IO at almost the same time and both + * decide that the page is now completely done. + */ + first = page_buffers(page); + local_irq_save(flags); + bit_spin_lock(BH_Uptodate_Lock, &first->b_state); + clear_buffer_async_read(bh); + unlock_buffer(bh); + tmp = bh; + do { + if (!buffer_uptodate(tmp)) + page_uptodate = 0; + if (buffer_async_read(tmp)) { + BUG_ON(!buffer_locked(tmp)); + goto still_busy; + } + tmp = tmp->b_this_page; + } while (tmp != bh); + bit_spin_unlock(BH_Uptodate_Lock, &first->b_state); + local_irq_restore(flags); + + /* + * If none of the buffers had errors and they are all + * uptodate then we can set the page uptodate. + */ + if (page_uptodate && !PageError(page)) + SetPageUptodate(page); + unlock_page(page); + return; + +still_busy: + bit_spin_unlock(BH_Uptodate_Lock, &first->b_state); + local_irq_restore(flags); + return; +} + +/* + * Completion handler for block_write_full_page() - pages which are unlocked + * during I/O, and which have PageWriteback cleared upon I/O completion. + */ +static void end_buffer_async_write(struct buffer_head *bh, int uptodate) +{ + char b[BDEVNAME_SIZE]; + unsigned long flags; + struct buffer_head *first; + struct buffer_head *tmp; + struct page *page; + + BUG_ON(!buffer_async_write(bh)); + + page = bh->b_page; + if (uptodate) { + set_buffer_uptodate(bh); + } else { + if (!quiet_error(bh)) { + buffer_io_error(bh); + printk(KERN_WARNING "lost page write due to " + "I/O error on %s\n", + bdevname(bh->b_bdev, b)); + } + set_bit(AS_EIO, &page->mapping->flags); + set_buffer_write_io_error(bh); + clear_buffer_uptodate(bh); + SetPageError(page); + } + + first = page_buffers(page); + local_irq_save(flags); + bit_spin_lock(BH_Uptodate_Lock, &first->b_state); + + clear_buffer_async_write(bh); + unlock_buffer(bh); + tmp = bh->b_this_page; + while (tmp != bh) { + if (buffer_async_write(tmp)) { + BUG_ON(!buffer_locked(tmp)); + goto still_busy; + } + tmp = tmp->b_this_page; + } + bit_spin_unlock(BH_Uptodate_Lock, &first->b_state); + local_irq_restore(flags); + end_page_writeback(page); + return; + +still_busy: + bit_spin_unlock(BH_Uptodate_Lock, &first->b_state); + local_irq_restore(flags); + return; +} + +/* + * If a page's buffers are under async readin (end_buffer_async_read + * completion) then there is a possibility that another thread of + * control could lock one of the buffers after it has completed + * but while some of the other buffers have not completed. This + * locked buffer would confuse end_buffer_async_read() into not unlocking + * the page. So the absence of BH_Async_Read tells end_buffer_async_read() + * that this buffer is not under async I/O. + * + * The page comes unlocked when it has no locked buffer_async buffers + * left. + * + * PageLocked prevents anyone starting new async I/O reads any of + * the buffers. + * + * PageWriteback is used to prevent simultaneous writeout of the same + * page. + * + * PageLocked prevents anyone from starting writeback of a page which is + * under read I/O (PageWriteback is only ever set against a locked page). + */ +static void mark_buffer_async_read(struct buffer_head *bh) +{ + bh->b_end_io = end_buffer_async_read; + set_buffer_async_read(bh); +} + +void mark_buffer_async_write(struct buffer_head *bh) +{ + bh->b_end_io = end_buffer_async_write; + set_buffer_async_write(bh); +} +EXPORT_SYMBOL(mark_buffer_async_write); + + +/* + * fs/buffer.c contains helper functions for buffer-backed address space's + * fsync functions. A common requirement for buffer-based filesystems is + * that certain data from the backing blockdev needs to be written out for + * a successful fsync(). For example, ext2 indirect blocks need to be + * written back and waited upon before fsync() returns. + * + * The functions mark_buffer_inode_dirty(), fsync_inode_buffers(), + * inode_has_buffers() and invalidate_inode_buffers() are provided for the + * management of a list of dependent buffers at ->i_mapping->private_list. + * + * Locking is a little subtle: try_to_free_buffers() will remove buffers + * from their controlling inode's queue when they are being freed. But + * try_to_free_buffers() will be operating against the *blockdev* mapping + * at the time, not against the S_ISREG file which depends on those buffers. + * So the locking for private_list is via the private_lock in the address_space + * which backs the buffers. Which is different from the address_space + * against which the buffers are listed. So for a particular address_space, + * mapping->private_lock does *not* protect mapping->private_list! In fact, + * mapping->private_list will always be protected by the backing blockdev's + * ->private_lock. + * + * Which introduces a requirement: all buffers on an address_space's + * ->private_list must be from the same address_space: the blockdev's. + * + * address_spaces which do not place buffers at ->private_list via these + * utility functions are free to use private_lock and private_list for + * whatever they want. The only requirement is that list_empty(private_list) + * be true at clear_inode() time. + * + * FIXME: clear_inode should not call invalidate_inode_buffers(). The + * filesystems should do that. invalidate_inode_buffers() should just go + * BUG_ON(!list_empty). + * + * FIXME: mark_buffer_dirty_inode() is a data-plane operation. It should + * take an address_space, not an inode. And it should be called + * mark_buffer_dirty_fsync() to clearly define why those buffers are being + * queued up. + * + * FIXME: mark_buffer_dirty_inode() doesn't need to add the buffer to the + * list if it is already on a list. Because if the buffer is on a list, + * it *must* already be on the right one. If not, the filesystem is being + * silly. This will save a ton of locking. But first we have to ensure + * that buffers are taken *off* the old inode's list when they are freed + * (presumably in truncate). That requires careful auditing of all + * filesystems (do it inside bforget()). It could also be done by bringing + * b_inode back. + */ + +/* + * The buffer's backing address_space's private_lock must be held + */ +static void __remove_assoc_queue(struct buffer_head *bh) +{ + list_del_init(&bh->b_assoc_buffers); + WARN_ON(!bh->b_assoc_map); + if (buffer_write_io_error(bh)) + set_bit(AS_EIO, &bh->b_assoc_map->flags); + bh->b_assoc_map = NULL; +} + +int inode_has_buffers(struct inode *inode) +{ + return !list_empty(&inode->i_data.private_list); +} + +/* + * osync is designed to support O_SYNC io. It waits synchronously for + * all already-submitted IO to complete, but does not queue any new + * writes to the disk. + * + * To do O_SYNC writes, just queue the buffer writes with ll_rw_block as + * you dirty the buffers, and then use osync_inode_buffers to wait for + * completion. Any other dirty buffers which are not yet queued for + * write will not be flushed to disk by the osync. + */ +static int osync_buffers_list(spinlock_t *lock, struct list_head *list) +{ + struct buffer_head *bh; + struct list_head *p; + int err = 0; + + spin_lock(lock); +repeat: + list_for_each_prev(p, list) { + bh = BH_ENTRY(p); + if (buffer_locked(bh)) { + get_bh(bh); + spin_unlock(lock); + wait_on_buffer(bh); + if (!buffer_uptodate(bh)) + err = -EIO; + brelse(bh); + spin_lock(lock); + goto repeat; + } + } + spin_unlock(lock); + return err; +} + +/** + * sync_mapping_buffers - write out & wait upon a mapping's "associated" buffers + * @mapping: the mapping which wants those buffers written + * + * Starts I/O against the buffers at mapping->private_list, and waits upon + * that I/O. + * + * Basically, this is a convenience function for fsync(). + * @mapping is a file or directory which needs those buffers to be written for + * a successful fsync(). + */ +int sync_mapping_buffers(struct address_space *mapping) +{ + struct address_space *buffer_mapping = mapping->assoc_mapping; + + if (buffer_mapping == NULL || list_empty(&mapping->private_list)) + return 0; + + return fsync_buffers_list(&buffer_mapping->private_lock, + &mapping->private_list); +} +EXPORT_SYMBOL(sync_mapping_buffers); + +/* + * Called when we've recently written block `bblock', and it is known that + * `bblock' was for a buffer_boundary() buffer. This means that the block at + * `bblock + 1' is probably a dirty indirect block. Hunt it down and, if it's + * dirty, schedule it for IO. So that indirects merge nicely with their data. + */ +void write_boundary_block(struct block_device *bdev, + sector_t bblock, unsigned blocksize) +{ + struct buffer_head *bh = __find_get_block(bdev, bblock + 1, blocksize); + if (bh) { + if (buffer_dirty(bh)) + ll_rw_block(WRITE, 1, &bh); + put_bh(bh); + } +} + +void mark_buffer_dirty_inode(struct buffer_head *bh, struct inode *inode) +{ + struct address_space *mapping = inode->i_mapping; + struct address_space *buffer_mapping = bh->b_page->mapping; + + mark_buffer_dirty(bh); + if (!mapping->assoc_mapping) { + mapping->assoc_mapping = buffer_mapping; + } else { + BUG_ON(mapping->assoc_mapping != buffer_mapping); + } + if (!bh->b_assoc_map) { + spin_lock(&buffer_mapping->private_lock); + list_move_tail(&bh->b_assoc_buffers, + &mapping->private_list); + bh->b_assoc_map = mapping; + spin_unlock(&buffer_mapping->private_lock); + } +} +EXPORT_SYMBOL(mark_buffer_dirty_inode); + +/* + * Mark the page dirty, and set it dirty in the radix tree, and mark the inode + * dirty. + * + * If warn is true, then emit a warning if the page is not uptodate and has + * not been truncated. + */ +static void __set_page_dirty(struct page *page, + struct address_space *mapping, int warn) +{ + spin_lock_irq(&mapping->tree_lock); + if (page->mapping) { /* Race with truncate? */ + WARN_ON_ONCE(warn && !PageUptodate(page)); + + if (mapping_cap_account_dirty(mapping)) { + __inc_zone_page_state(page, NR_FILE_DIRTY); + __inc_bdi_stat(mapping->backing_dev_info, + BDI_RECLAIMABLE); + task_dirty_inc(current); + task_io_account_write(PAGE_CACHE_SIZE); + } + radix_tree_tag_set(&mapping->page_tree, + page_index(page), PAGECACHE_TAG_DIRTY); + } + spin_unlock_irq(&mapping->tree_lock); + __mark_inode_dirty(mapping->host, I_DIRTY_PAGES); +} + +/* + * Add a page to the dirty page list. + * + * It is a sad fact of life that this function is called from several places + * deeply under spinlocking. It may not sleep. + * + * If the page has buffers, the uptodate buffers are set dirty, to preserve + * dirty-state coherency between the page and the buffers. It the page does + * not have buffers then when they are later attached they will all be set + * dirty. + * + * The buffers are dirtied before the page is dirtied. There's a small race + * window in which a writepage caller may see the page cleanness but not the + * buffer dirtiness. That's fine. If this code were to set the page dirty + * before the buffers, a concurrent writepage caller could clear the page dirty + * bit, see a bunch of clean buffers and we'd end up with dirty buffers/clean + * page on the dirty page list. + * + * We use private_lock to lock against try_to_free_buffers while using the + * page's buffer list. Also use this to protect against clean buffers being + * added to the page after it was set dirty. + * + * FIXME: may need to call ->reservepage here as well. That's rather up to the + * address_space though. + */ +int __set_page_dirty_buffers(struct page *page) +{ + int newly_dirty; + struct address_space *mapping = page_mapping(page); + + if (unlikely(!mapping)) + return !TestSetPageDirty(page); + + spin_lock(&mapping->private_lock); + if (page_has_buffers(page)) { + struct buffer_head *head = page_buffers(page); + struct buffer_head *bh = head; + + do { + set_buffer_dirty(bh); + bh = bh->b_this_page; + } while (bh != head); + } + newly_dirty = !TestSetPageDirty(page); + spin_unlock(&mapping->private_lock); + + if (newly_dirty) + __set_page_dirty(page, mapping, 1); + return newly_dirty; +} +EXPORT_SYMBOL(__set_page_dirty_buffers); + +/* + * Write out and wait upon a list of buffers. + * + * We have conflicting pressures: we want to make sure that all + * initially dirty buffers get waited on, but that any subsequently + * dirtied buffers don't. After all, we don't want fsync to last + * forever if somebody is actively writing to the file. + * + * Do this in two main stages: first we copy dirty buffers to a + * temporary inode list, queueing the writes as we go. Then we clean + * up, waiting for those writes to complete. + * + * During this second stage, any subsequent updates to the file may end + * up refiling the buffer on the original inode's dirty list again, so + * there is a chance we will end up with a buffer queued for write but + * not yet completed on that list. So, as a final cleanup we go through + * the osync code to catch these locked, dirty buffers without requeuing + * any newly dirty buffers for write. + */ +static int fsync_buffers_list(spinlock_t *lock, struct list_head *list) +{ + struct buffer_head *bh; + struct list_head tmp; + struct address_space *mapping; + int err = 0, err2; + + INIT_LIST_HEAD(&tmp); + + spin_lock(lock); + while (!list_empty(list)) { + bh = BH_ENTRY(list->next); + mapping = bh->b_assoc_map; + __remove_assoc_queue(bh); + /* Avoid race with mark_buffer_dirty_inode() which does + * a lockless check and we rely on seeing the dirty bit */ + smp_mb(); + if (buffer_dirty(bh) || buffer_locked(bh)) { + list_add(&bh->b_assoc_buffers, &tmp); + bh->b_assoc_map = mapping; + if (buffer_dirty(bh)) { + get_bh(bh); + spin_unlock(lock); + /* + * Ensure any pending I/O completes so that + * ll_rw_block() actually writes the current + * contents - it is a noop if I/O is still in + * flight on potentially older contents. + */ + ll_rw_block(SWRITE_SYNC, 1, &bh); + brelse(bh); + spin_lock(lock); + } + } + } + + while (!list_empty(&tmp)) { + bh = BH_ENTRY(tmp.prev); + get_bh(bh); + mapping = bh->b_assoc_map; + __remove_assoc_queue(bh); + /* Avoid race with mark_buffer_dirty_inode() which does + * a lockless check and we rely on seeing the dirty bit */ + smp_mb(); + if (buffer_dirty(bh)) { + list_add(&bh->b_assoc_buffers, + &mapping->private_list); + bh->b_assoc_map = mapping; + } + spin_unlock(lock); + wait_on_buffer(bh); + if (!buffer_uptodate(bh)) + err = -EIO; + brelse(bh); + spin_lock(lock); + } + + spin_unlock(lock); + err2 = osync_buffers_list(lock, list); + if (err) + return err; + else + return err2; +} + +/* + * Invalidate any and all dirty buffers on a given inode. We are + * probably unmounting the fs, but that doesn't mean we have already + * done a sync(). Just drop the buffers from the inode list. + * + * NOTE: we take the inode's blockdev's mapping's private_lock. Which + * assumes that all the buffers are against the blockdev. Not true + * for reiserfs. + */ +void invalidate_inode_buffers(struct inode *inode) +{ + if (inode_has_buffers(inode)) { + struct address_space *mapping = &inode->i_data; + struct list_head *list = &mapping->private_list; + struct address_space *buffer_mapping = mapping->assoc_mapping; + + spin_lock(&buffer_mapping->private_lock); + while (!list_empty(list)) + __remove_assoc_queue(BH_ENTRY(list->next)); + spin_unlock(&buffer_mapping->private_lock); + } +} +EXPORT_SYMBOL(invalidate_inode_buffers); + +/* + * Remove any clean buffers from the inode's buffer list. This is called + * when we're trying to free the inode itself. Those buffers can pin it. + * + * Returns true if all buffers were removed. + */ +int remove_inode_buffers(struct inode *inode) +{ + int ret = 1; + + if (inode_has_buffers(inode)) { + struct address_space *mapping = &inode->i_data; + struct list_head *list = &mapping->private_list; + struct address_space *buffer_mapping = mapping->assoc_mapping; + + spin_lock(&buffer_mapping->private_lock); + while (!list_empty(list)) { + struct buffer_head *bh = BH_ENTRY(list->next); + if (buffer_dirty(bh)) { + ret = 0; + break; + } + __remove_assoc_queue(bh); + } + spin_unlock(&buffer_mapping->private_lock); + } + return ret; +} + +/* + * Create the appropriate buffers when given a page for data area and + * the size of each buffer.. Use the bh->b_this_page linked list to + * follow the buffers created. Return NULL if unable to create more + * buffers. + * + * The retry flag is used to differentiate async IO (paging, swapping) + * which may not fail from ordinary buffer allocations. + */ +struct buffer_head *alloc_page_buffers(struct page *page, unsigned long size, + int retry) +{ + struct buffer_head *bh, *head; + long offset; + +try_again: + head = NULL; + offset = PAGE_SIZE; + while ((offset -= size) >= 0) { + bh = alloc_buffer_head(GFP_NOFS); + if (!bh) + goto no_grow; + + bh->b_bdev = NULL; + bh->b_this_page = head; + bh->b_blocknr = -1; + head = bh; + + bh->b_state = 0; + atomic_set(&bh->b_count, 0); + bh->b_private = NULL; + bh->b_size = size; + + /* Link the buffer to its page */ + set_bh_page(bh, page, offset); + + init_buffer(bh, NULL, NULL); + } + return head; +/* + * In case anything failed, we just free everything we got. + */ +no_grow: + if (head) { + do { + bh = head; + head = head->b_this_page; + free_buffer_head(bh); + } while (head); + } + + /* + * Return failure for non-async IO requests. Async IO requests + * are not allowed to fail, so we have to wait until buffer heads + * become available. But we don't want tasks sleeping with + * partially complete buffers, so all were released above. + */ + if (!retry) + return NULL; + + /* We're _really_ low on memory. Now we just + * wait for old buffer heads to become free due to + * finishing IO. Since this is an async request and + * the reserve list is empty, we're sure there are + * async buffer heads in use. + */ + free_more_memory(); + goto try_again; +} +EXPORT_SYMBOL_GPL(alloc_page_buffers); + +static inline void +link_dev_buffers(struct page *page, struct buffer_head *head) +{ + struct buffer_head *bh, *tail; + + bh = head; + do { + tail = bh; + bh = bh->b_this_page; + } while (bh); + tail->b_this_page = head; + attach_page_buffers(page, head); +} + +/* + * Initialise the state of a blockdev page's buffers. + */ +static void +init_page_buffers(struct page *page, struct block_device *bdev, + sector_t block, int size) +{ + struct buffer_head *head = page_buffers(page); + struct buffer_head *bh = head; + int uptodate = PageUptodate(page); + + do { + if (!buffer_mapped(bh)) { + init_buffer(bh, NULL, NULL); + bh->b_bdev = bdev; + bh->b_blocknr = block; + if (uptodate) + set_buffer_uptodate(bh); + set_buffer_mapped(bh); + } + block++; + bh = bh->b_this_page; + } while (bh != head); +} + +/* + * Create the page-cache page that contains the requested block. + * + * This is user purely for blockdev mappings. + */ +static struct page * +grow_dev_page(struct block_device *bdev, sector_t block, + pgoff_t index, int size) +{ + struct inode *inode = bdev->bd_inode; + struct page *page; + struct buffer_head *bh; + +#ifdef DDE_LINUX + WARN_UNIMPL; + return NULL; +#endif + + page = find_or_create_page(inode->i_mapping, index, + (mapping_gfp_mask(inode->i_mapping) & ~__GFP_FS)|__GFP_MOVABLE); + if (!page) + return NULL; + + BUG_ON(!PageLocked(page)); + + if (page_has_buffers(page)) { + bh = page_buffers(page); + if (bh->b_size == size) { + init_page_buffers(page, bdev, block, size); + return page; + } + if (!try_to_free_buffers(page)) + goto failed; + } + + /* + * Allocate some buffers for this page + */ + bh = alloc_page_buffers(page, size, 0); + if (!bh) + goto failed; + + /* + * Link the page to the buffers and initialise them. Take the + * lock to be atomic wrt __find_get_block(), which does not + * run under the page lock. + */ + spin_lock(&inode->i_mapping->private_lock); + link_dev_buffers(page, bh); + init_page_buffers(page, bdev, block, size); + spin_unlock(&inode->i_mapping->private_lock); + return page; + +failed: + BUG(); + unlock_page(page); + page_cache_release(page); + return NULL; +} + +/* + * Create buffers for the specified block device block's page. If + * that page was dirty, the buffers are set dirty also. + */ +static int +grow_buffers(struct block_device *bdev, sector_t block, int size) +{ + struct page *page; + pgoff_t index; + int sizebits; + + sizebits = -1; + do { + sizebits++; + } while ((size << sizebits) < PAGE_SIZE); + + index = block >> sizebits; + + /* + * Check for a block which wants to lie outside our maximum possible + * pagecache index. (this comparison is done using sector_t types). + */ + if (unlikely(index != block >> sizebits)) { + char b[BDEVNAME_SIZE]; + + printk(KERN_ERR "%s: requested out-of-range block %llu for " + "device %s\n", + __func__, (unsigned long long)block, + bdevname(bdev, b)); + return -EIO; + } + block = index << sizebits; + /* Create a page with the proper size buffers.. */ + page = grow_dev_page(bdev, block, index, size); + if (!page) + return 0; + unlock_page(page); + page_cache_release(page); + return 1; +} + +static struct buffer_head * +__getblk_slow(struct block_device *bdev, sector_t block, int size) +{ + /* Size must be multiple of hard sectorsize */ + if (unlikely(size & (bdev_hardsect_size(bdev)-1) || + (size < 512 || size > PAGE_SIZE))) { + printk(KERN_ERR "getblk(): invalid block size %d requested\n", + size); + printk(KERN_ERR "hardsect size: %d\n", + bdev_hardsect_size(bdev)); + + dump_stack(); + return NULL; + } + + for (;;) { + struct buffer_head * bh; + int ret; + + bh = __find_get_block(bdev, block, size); + if (bh) + return bh; + + ret = grow_buffers(bdev, block, size); + if (ret < 0) + return NULL; + if (ret == 0) + free_more_memory(); + } +} + +/* + * The relationship between dirty buffers and dirty pages: + * + * Whenever a page has any dirty buffers, the page's dirty bit is set, and + * the page is tagged dirty in its radix tree. + * + * At all times, the dirtiness of the buffers represents the dirtiness of + * subsections of the page. If the page has buffers, the page dirty bit is + * merely a hint about the true dirty state. + * + * When a page is set dirty in its entirety, all its buffers are marked dirty + * (if the page has buffers). + * + * When a buffer is marked dirty, its page is dirtied, but the page's other + * buffers are not. + * + * Also. When blockdev buffers are explicitly read with bread(), they + * individually become uptodate. But their backing page remains not + * uptodate - even if all of its buffers are uptodate. A subsequent + * block_read_full_page() against that page will discover all the uptodate + * buffers, will set the page uptodate and will perform no I/O. + */ + +/** + * mark_buffer_dirty - mark a buffer_head as needing writeout + * @bh: the buffer_head to mark dirty + * + * mark_buffer_dirty() will set the dirty bit against the buffer, then set its + * backing page dirty, then tag the page as dirty in its address_space's radix + * tree and then attach the address_space's inode to its superblock's dirty + * inode list. + * + * mark_buffer_dirty() is atomic. It takes bh->b_page->mapping->private_lock, + * mapping->tree_lock and the global inode_lock. + */ +void mark_buffer_dirty(struct buffer_head *bh) +{ +#ifndef DDE_LINUX + WARN_ON_ONCE(!buffer_uptodate(bh)); + + /* + * Very *carefully* optimize the it-is-already-dirty case. + * + * Don't let the final "is it dirty" escape to before we + * perhaps modified the buffer. + */ + if (buffer_dirty(bh)) { + smp_mb(); + if (buffer_dirty(bh)) + return; + } + + if (!test_set_buffer_dirty(bh)) { + struct page *page = bh->b_page; + if (!TestSetPageDirty(page)) + __set_page_dirty(page, page_mapping(page), 0); + } +#else + WARN_UNIMPL; +#endif +} + +/* + * Decrement a buffer_head's reference count. If all buffers against a page + * have zero reference count, are clean and unlocked, and if the page is clean + * and unlocked then try_to_free_buffers() may strip the buffers from the page + * in preparation for freeing it (sometimes, rarely, buffers are removed from + * a page but it ends up not being freed, and buffers may later be reattached). + */ +void __brelse(struct buffer_head * buf) +{ + if (atomic_read(&buf->b_count)) { + put_bh(buf); + return; + } + WARN(1, KERN_ERR "VFS: brelse: Trying to free free buffer\n"); +} + +/* + * bforget() is like brelse(), except it discards any + * potentially dirty data. + */ +void __bforget(struct buffer_head *bh) +{ + clear_buffer_dirty(bh); + if (bh->b_assoc_map) { + struct address_space *buffer_mapping = bh->b_page->mapping; + + spin_lock(&buffer_mapping->private_lock); + list_del_init(&bh->b_assoc_buffers); + bh->b_assoc_map = NULL; + spin_unlock(&buffer_mapping->private_lock); + } + __brelse(bh); +} + +static struct buffer_head *__bread_slow(struct buffer_head *bh) +{ + lock_buffer(bh); + if (buffer_uptodate(bh)) { + unlock_buffer(bh); + return bh; + } else { + get_bh(bh); + bh->b_end_io = end_buffer_read_sync; + submit_bh(READ, bh); + wait_on_buffer(bh); + if (buffer_uptodate(bh)) + return bh; + } + brelse(bh); + return NULL; +} + +/* + * Per-cpu buffer LRU implementation. To reduce the cost of __find_get_block(). + * The bhs[] array is sorted - newest buffer is at bhs[0]. Buffers have their + * refcount elevated by one when they're in an LRU. A buffer can only appear + * once in a particular CPU's LRU. A single buffer can be present in multiple + * CPU's LRUs at the same time. + * + * This is a transparent caching front-end to sb_bread(), sb_getblk() and + * sb_find_get_block(). + * + * The LRUs themselves only need locking against invalidate_bh_lrus. We use + * a local interrupt disable for that. + */ + +#define BH_LRU_SIZE 8 + +struct bh_lru { + struct buffer_head *bhs[BH_LRU_SIZE]; +}; + +static DEFINE_PER_CPU(struct bh_lru, bh_lrus) = {{ NULL }}; + +#ifdef CONFIG_SMP +#define bh_lru_lock() local_irq_disable() +#define bh_lru_unlock() local_irq_enable() +#else +#define bh_lru_lock() preempt_disable() +#define bh_lru_unlock() preempt_enable() +#endif + +static inline void check_irqs_on(void) +{ +#ifdef irqs_disabled + BUG_ON(irqs_disabled()); +#endif +} + +/* + * The LRU management algorithm is dopey-but-simple. Sorry. + */ +static void bh_lru_install(struct buffer_head *bh) +{ + struct buffer_head *evictee = NULL; + struct bh_lru *lru; + + check_irqs_on(); + bh_lru_lock(); + lru = &__get_cpu_var(bh_lrus); + if (lru->bhs[0] != bh) { + struct buffer_head *bhs[BH_LRU_SIZE]; + int in; + int out = 0; + + get_bh(bh); + bhs[out++] = bh; + for (in = 0; in < BH_LRU_SIZE; in++) { + struct buffer_head *bh2 = lru->bhs[in]; + + if (bh2 == bh) { + __brelse(bh2); + } else { + if (out >= BH_LRU_SIZE) { + BUG_ON(evictee != NULL); + evictee = bh2; + } else { + bhs[out++] = bh2; + } + } + } + while (out < BH_LRU_SIZE) + bhs[out++] = NULL; + memcpy(lru->bhs, bhs, sizeof(bhs)); + } + bh_lru_unlock(); + + if (evictee) + __brelse(evictee); +} + +/* + * Look up the bh in this cpu's LRU. If it's there, move it to the head. + */ +static struct buffer_head * +lookup_bh_lru(struct block_device *bdev, sector_t block, unsigned size) +{ + struct buffer_head *ret = NULL; + struct bh_lru *lru; + unsigned int i; + + check_irqs_on(); + bh_lru_lock(); + lru = &__get_cpu_var(bh_lrus); + for (i = 0; i < BH_LRU_SIZE; i++) { + struct buffer_head *bh = lru->bhs[i]; + + if (bh && bh->b_bdev == bdev && + bh->b_blocknr == block && bh->b_size == size) { + if (i) { + while (i) { + lru->bhs[i] = lru->bhs[i - 1]; + i--; + } + lru->bhs[0] = bh; + } + get_bh(bh); + ret = bh; + break; + } + } + bh_lru_unlock(); + return ret; +} + +/* + * Perform a pagecache lookup for the matching buffer. If it's there, refresh + * it in the LRU and mark it as accessed. If it is not present then return + * NULL + */ +struct buffer_head * +__find_get_block(struct block_device *bdev, sector_t block, unsigned size) +{ + struct buffer_head *bh = lookup_bh_lru(bdev, block, size); + + if (bh == NULL) { + bh = __find_get_block_slow(bdev, block); + if (bh) + bh_lru_install(bh); + } + if (bh) + touch_buffer(bh); + return bh; +} +EXPORT_SYMBOL(__find_get_block); + +/* + * __getblk will locate (and, if necessary, create) the buffer_head + * which corresponds to the passed block_device, block and size. The + * returned buffer has its reference count incremented. + * + * __getblk() cannot fail - it just keeps trying. If you pass it an + * illegal block number, __getblk() will happily return a buffer_head + * which represents the non-existent block. Very weird. + * + * __getblk() will lock up the machine if grow_dev_page's try_to_free_buffers() + * attempt is failing. FIXME, perhaps? + */ +struct buffer_head * +__getblk(struct block_device *bdev, sector_t block, unsigned size) +{ + struct buffer_head *bh = __find_get_block(bdev, block, size); + + might_sleep(); + if (bh == NULL) + bh = __getblk_slow(bdev, block, size); + return bh; +} +EXPORT_SYMBOL(__getblk); + +/* + * Do async read-ahead on a buffer.. + */ +void __breadahead(struct block_device *bdev, sector_t block, unsigned size) +{ + struct buffer_head *bh = __getblk(bdev, block, size); + if (likely(bh)) { + ll_rw_block(READA, 1, &bh); + brelse(bh); + } +} +EXPORT_SYMBOL(__breadahead); + +/** + * __bread() - reads a specified block and returns the bh + * @bdev: the block_device to read from + * @block: number of block + * @size: size (in bytes) to read + * + * Reads a specified block, and returns buffer head that contains it. + * It returns NULL if the block was unreadable. + */ +struct buffer_head * +__bread(struct block_device *bdev, sector_t block, unsigned size) +{ + struct buffer_head *bh = __getblk(bdev, block, size); + + if (likely(bh) && !buffer_uptodate(bh)) + bh = __bread_slow(bh); + return bh; +} +EXPORT_SYMBOL(__bread); + +/* + * invalidate_bh_lrus() is called rarely - but not only at unmount. + * This doesn't race because it runs in each cpu either in irq + * or with preempt disabled. + */ +static void invalidate_bh_lru(void *arg) +{ + struct bh_lru *b = &get_cpu_var(bh_lrus); + int i; + + for (i = 0; i < BH_LRU_SIZE; i++) { + brelse(b->bhs[i]); + b->bhs[i] = NULL; + } + put_cpu_var(bh_lrus); +} + +void invalidate_bh_lrus(void) +{ +#ifndef DDE_LINUX + on_each_cpu(invalidate_bh_lru, NULL, 1); +#endif +} +EXPORT_SYMBOL_GPL(invalidate_bh_lrus); + +void set_bh_page(struct buffer_head *bh, + struct page *page, unsigned long offset) +{ + bh->b_page = page; + BUG_ON(offset >= PAGE_SIZE); + if (PageHighMem(page)) + /* + * This catches illegal uses and preserves the offset: + */ + bh->b_data = (char *)(0 + offset); + else + bh->b_data = page_address(page) + offset; +} +EXPORT_SYMBOL(set_bh_page); + +/* + * Called when truncating a buffer on a page completely. + */ +static void discard_buffer(struct buffer_head * bh) +{ + lock_buffer(bh); + clear_buffer_dirty(bh); + bh->b_bdev = NULL; + clear_buffer_mapped(bh); + clear_buffer_req(bh); + clear_buffer_new(bh); + clear_buffer_delay(bh); + clear_buffer_unwritten(bh); + unlock_buffer(bh); +} + +/** + * block_invalidatepage - invalidate part of all of a buffer-backed page + * + * @page: the page which is affected + * @offset: the index of the truncation point + * + * block_invalidatepage() is called when all or part of the page has become + * invalidatedby a truncate operation. + * + * block_invalidatepage() does not have to release all buffers, but it must + * ensure that no dirty buffer is left outside @offset and that no I/O + * is underway against any of the blocks which are outside the truncation + * point. Because the caller is about to free (and possibly reuse) those + * blocks on-disk. + */ +void block_invalidatepage(struct page *page, unsigned long offset) +{ + struct buffer_head *head, *bh, *next; + unsigned int curr_off = 0; + + BUG_ON(!PageLocked(page)); + if (!page_has_buffers(page)) + goto out; + + head = page_buffers(page); + bh = head; + do { + unsigned int next_off = curr_off + bh->b_size; + next = bh->b_this_page; + + /* + * is this block fully invalidated? + */ + if (offset <= curr_off) + discard_buffer(bh); + curr_off = next_off; + bh = next; + } while (bh != head); + + /* + * We release buffers only if the entire page is being invalidated. + * The get_block cached value has been unconditionally invalidated, + * so real IO is not possible anymore. + */ + if (offset == 0) + try_to_release_page(page, 0); +out: + return; +} +EXPORT_SYMBOL(block_invalidatepage); + +/* + * We attach and possibly dirty the buffers atomically wrt + * __set_page_dirty_buffers() via private_lock. try_to_free_buffers + * is already excluded via the page lock. + */ +void create_empty_buffers(struct page *page, + unsigned long blocksize, unsigned long b_state) +{ + struct buffer_head *bh, *head, *tail; + + head = alloc_page_buffers(page, blocksize, 1); + bh = head; + do { + bh->b_state |= b_state; + tail = bh; + bh = bh->b_this_page; + } while (bh); + tail->b_this_page = head; + + spin_lock(&page->mapping->private_lock); + if (PageUptodate(page) || PageDirty(page)) { + bh = head; + do { + if (PageDirty(page)) + set_buffer_dirty(bh); + if (PageUptodate(page)) + set_buffer_uptodate(bh); + bh = bh->b_this_page; + } while (bh != head); + } + attach_page_buffers(page, head); + spin_unlock(&page->mapping->private_lock); +} +EXPORT_SYMBOL(create_empty_buffers); + +/* + * We are taking a block for data and we don't want any output from any + * buffer-cache aliases starting from return from that function and + * until the moment when something will explicitly mark the buffer + * dirty (hopefully that will not happen until we will free that block ;-) + * We don't even need to mark it not-uptodate - nobody can expect + * anything from a newly allocated buffer anyway. We used to used + * unmap_buffer() for such invalidation, but that was wrong. We definitely + * don't want to mark the alias unmapped, for example - it would confuse + * anyone who might pick it with bread() afterwards... + * + * Also.. Note that bforget() doesn't lock the buffer. So there can + * be writeout I/O going on against recently-freed buffers. We don't + * wait on that I/O in bforget() - it's more efficient to wait on the I/O + * only if we really need to. That happens here. + */ +void unmap_underlying_metadata(struct block_device *bdev, sector_t block) +{ + struct buffer_head *old_bh; + + might_sleep(); + + old_bh = __find_get_block_slow(bdev, block); + if (old_bh) { + clear_buffer_dirty(old_bh); + wait_on_buffer(old_bh); + clear_buffer_req(old_bh); + __brelse(old_bh); + } +} +EXPORT_SYMBOL(unmap_underlying_metadata); + +/* + * NOTE! All mapped/uptodate combinations are valid: + * + * Mapped Uptodate Meaning + * + * No No "unknown" - must do get_block() + * No Yes "hole" - zero-filled + * Yes No "allocated" - allocated on disk, not read in + * Yes Yes "valid" - allocated and up-to-date in memory. + * + * "Dirty" is valid only with the last case (mapped+uptodate). + */ + +/* + * While block_write_full_page is writing back the dirty buffers under + * the page lock, whoever dirtied the buffers may decide to clean them + * again at any time. We handle that by only looking at the buffer + * state inside lock_buffer(). + * + * If block_write_full_page() is called for regular writeback + * (wbc->sync_mode == WB_SYNC_NONE) then it will redirty a page which has a + * locked buffer. This only can happen if someone has written the buffer + * directly, with submit_bh(). At the address_space level PageWriteback + * prevents this contention from occurring. + */ +static int __block_write_full_page(struct inode *inode, struct page *page, + get_block_t *get_block, struct writeback_control *wbc) +{ + int err; + sector_t block; + sector_t last_block; + struct buffer_head *bh, *head; + const unsigned blocksize = 1 << inode->i_blkbits; + int nr_underway = 0; + + BUG_ON(!PageLocked(page)); + + last_block = (i_size_read(inode) - 1) >> inode->i_blkbits; + + if (!page_has_buffers(page)) { + create_empty_buffers(page, blocksize, + (1 << BH_Dirty)|(1 << BH_Uptodate)); + } + + /* + * Be very careful. We have no exclusion from __set_page_dirty_buffers + * here, and the (potentially unmapped) buffers may become dirty at + * any time. If a buffer becomes dirty here after we've inspected it + * then we just miss that fact, and the page stays dirty. + * + * Buffers outside i_size may be dirtied by __set_page_dirty_buffers; + * handle that here by just cleaning them. + */ + + block = (sector_t)page->index << (PAGE_CACHE_SHIFT - inode->i_blkbits); + head = page_buffers(page); + bh = head; + + /* + * Get all the dirty buffers mapped to disk addresses and + * handle any aliases from the underlying blockdev's mapping. + */ + do { + if (block > last_block) { + /* + * mapped buffers outside i_size will occur, because + * this page can be outside i_size when there is a + * truncate in progress. + */ + /* + * The buffer was zeroed by block_write_full_page() + */ + clear_buffer_dirty(bh); + set_buffer_uptodate(bh); + } else if ((!buffer_mapped(bh) || buffer_delay(bh)) && + buffer_dirty(bh)) { + WARN_ON(bh->b_size != blocksize); + err = get_block(inode, block, bh, 1); + if (err) + goto recover; + clear_buffer_delay(bh); + if (buffer_new(bh)) { + /* blockdev mappings never come here */ + clear_buffer_new(bh); + unmap_underlying_metadata(bh->b_bdev, + bh->b_blocknr); + } + } + bh = bh->b_this_page; + block++; + } while (bh != head); + + do { + if (!buffer_mapped(bh)) + continue; + /* + * If it's a fully non-blocking write attempt and we cannot + * lock the buffer then redirty the page. Note that this can + * potentially cause a busy-wait loop from pdflush and kswapd + * activity, but those code paths have their own higher-level + * throttling. + */ + if (wbc->sync_mode != WB_SYNC_NONE || !wbc->nonblocking) { + lock_buffer(bh); + } else if (!trylock_buffer(bh)) { + redirty_page_for_writepage(wbc, page); + continue; + } + if (test_clear_buffer_dirty(bh)) { + mark_buffer_async_write(bh); + } else { + unlock_buffer(bh); + } + } while ((bh = bh->b_this_page) != head); + + /* + * The page and its buffers are protected by PageWriteback(), so we can + * drop the bh refcounts early. + */ + BUG_ON(PageWriteback(page)); + set_page_writeback(page); + + do { + struct buffer_head *next = bh->b_this_page; + if (buffer_async_write(bh)) { + submit_bh(WRITE, bh); + nr_underway++; + } + bh = next; + } while (bh != head); + unlock_page(page); + + err = 0; +done: + if (nr_underway == 0) { + /* + * The page was marked dirty, but the buffers were + * clean. Someone wrote them back by hand with + * ll_rw_block/submit_bh. A rare case. + */ + end_page_writeback(page); + + /* + * The page and buffer_heads can be released at any time from + * here on. + */ + } + return err; + +recover: + /* + * ENOSPC, or some other error. We may already have added some + * blocks to the file, so we need to write these out to avoid + * exposing stale data. + * The page is currently locked and not marked for writeback + */ + bh = head; + /* Recovery: lock and submit the mapped buffers */ + do { + if (buffer_mapped(bh) && buffer_dirty(bh) && + !buffer_delay(bh)) { + lock_buffer(bh); + mark_buffer_async_write(bh); + } else { + /* + * The buffer may have been set dirty during + * attachment to a dirty page. + */ + clear_buffer_dirty(bh); + } + } while ((bh = bh->b_this_page) != head); + SetPageError(page); + BUG_ON(PageWriteback(page)); + mapping_set_error(page->mapping, err); + set_page_writeback(page); + do { + struct buffer_head *next = bh->b_this_page; + if (buffer_async_write(bh)) { + clear_buffer_dirty(bh); + submit_bh(WRITE, bh); + nr_underway++; + } + bh = next; + } while (bh != head); + unlock_page(page); + goto done; +} + +/* + * If a page has any new buffers, zero them out here, and mark them uptodate + * and dirty so they'll be written out (in order to prevent uninitialised + * block data from leaking). And clear the new bit. + */ +void page_zero_new_buffers(struct page *page, unsigned from, unsigned to) +{ + unsigned int block_start, block_end; + struct buffer_head *head, *bh; + + BUG_ON(!PageLocked(page)); + if (!page_has_buffers(page)) + return; + + bh = head = page_buffers(page); + block_start = 0; + do { + block_end = block_start + bh->b_size; + + if (buffer_new(bh)) { + if (block_end > from && block_start < to) { + if (!PageUptodate(page)) { + unsigned start, size; + + start = max(from, block_start); + size = min(to, block_end) - start; + + zero_user(page, start, size); + set_buffer_uptodate(bh); + } + + clear_buffer_new(bh); + mark_buffer_dirty(bh); + } + } + + block_start = block_end; + bh = bh->b_this_page; + } while (bh != head); +} +EXPORT_SYMBOL(page_zero_new_buffers); + +static int __block_prepare_write(struct inode *inode, struct page *page, + unsigned from, unsigned to, get_block_t *get_block) +{ + unsigned block_start, block_end; + sector_t block; + int err = 0; + unsigned blocksize, bbits; + struct buffer_head *bh, *head, *wait[2], **wait_bh=wait; + + BUG_ON(!PageLocked(page)); + BUG_ON(from > PAGE_CACHE_SIZE); + BUG_ON(to > PAGE_CACHE_SIZE); + BUG_ON(from > to); + + blocksize = 1 << inode->i_blkbits; + if (!page_has_buffers(page)) + create_empty_buffers(page, blocksize, 0); + head = page_buffers(page); + + bbits = inode->i_blkbits; + block = (sector_t)page->index << (PAGE_CACHE_SHIFT - bbits); + + for(bh = head, block_start = 0; bh != head || !block_start; + block++, block_start=block_end, bh = bh->b_this_page) { + block_end = block_start + blocksize; + if (block_end <= from || block_start >= to) { + if (PageUptodate(page)) { + if (!buffer_uptodate(bh)) + set_buffer_uptodate(bh); + } + continue; + } + if (buffer_new(bh)) + clear_buffer_new(bh); + if (!buffer_mapped(bh)) { + WARN_ON(bh->b_size != blocksize); + err = get_block(inode, block, bh, 1); + if (err) + break; + if (buffer_new(bh)) { + unmap_underlying_metadata(bh->b_bdev, + bh->b_blocknr); + if (PageUptodate(page)) { + clear_buffer_new(bh); + set_buffer_uptodate(bh); + mark_buffer_dirty(bh); + continue; + } + if (block_end > to || block_start < from) + zero_user_segments(page, + to, block_end, + block_start, from); + continue; + } + } + if (PageUptodate(page)) { + if (!buffer_uptodate(bh)) + set_buffer_uptodate(bh); + continue; + } + if (!buffer_uptodate(bh) && !buffer_delay(bh) && + !buffer_unwritten(bh) && + (block_start < from || block_end > to)) { + ll_rw_block(READ, 1, &bh); + *wait_bh++=bh; + } + } + /* + * If we issued read requests - let them complete. + */ + while(wait_bh > wait) { + wait_on_buffer(*--wait_bh); + if (!buffer_uptodate(*wait_bh)) + err = -EIO; + } + if (unlikely(err)) + page_zero_new_buffers(page, from, to); + return err; +} + +static int __block_commit_write(struct inode *inode, struct page *page, + unsigned from, unsigned to) +{ + unsigned block_start, block_end; + int partial = 0; + unsigned blocksize; + struct buffer_head *bh, *head; + + blocksize = 1 << inode->i_blkbits; + + for(bh = head = page_buffers(page), block_start = 0; + bh != head || !block_start; + block_start=block_end, bh = bh->b_this_page) { + block_end = block_start + blocksize; + if (block_end <= from || block_start >= to) { + if (!buffer_uptodate(bh)) + partial = 1; + } else { + set_buffer_uptodate(bh); + mark_buffer_dirty(bh); + } + clear_buffer_new(bh); + } + + /* + * If this is a partial write which happened to make all buffers + * uptodate then we can optimize away a bogus readpage() for + * the next read(). Here we 'discover' whether the page went + * uptodate as a result of this (potentially partial) write. + */ + if (!partial) + SetPageUptodate(page); + return 0; +} + +/* + * block_write_begin takes care of the basic task of block allocation and + * bringing partial write blocks uptodate first. + * + * If *pagep is not NULL, then block_write_begin uses the locked page + * at *pagep rather than allocating its own. In this case, the page will + * not be unlocked or deallocated on failure. + */ +int block_write_begin(struct file *file, struct address_space *mapping, + loff_t pos, unsigned len, unsigned flags, + struct page **pagep, void **fsdata, + get_block_t *get_block) +{ +#ifndef DDE_LINUX + struct inode *inode = mapping->host; + int status = 0; + struct page *page; + pgoff_t index; + unsigned start, end; + int ownpage = 0; + + index = pos >> PAGE_CACHE_SHIFT; + start = pos & (PAGE_CACHE_SIZE - 1); + end = start + len; + + page = *pagep; + if (page == NULL) { + ownpage = 1; + page = grab_cache_page_write_begin(mapping, index, flags); + if (!page) { + status = -ENOMEM; + goto out; + } + *pagep = page; + } else + BUG_ON(!PageLocked(page)); + + status = __block_prepare_write(inode, page, start, end, get_block); + if (unlikely(status)) { + ClearPageUptodate(page); + + if (ownpage) { + unlock_page(page); + page_cache_release(page); + *pagep = NULL; + +#ifndef DDE_LINUX + /* + * prepare_write() may have instantiated a few blocks + * outside i_size. Trim these off again. Don't need + * i_size_read because we hold i_mutex. + */ + if (pos + len > inode->i_size) + vmtruncate(inode, inode->i_size); +#endif + } + } + +out: + return status; +#else + WARN_UNIMPL; + return -1; +#endif +} +EXPORT_SYMBOL(block_write_begin); + +int block_write_end(struct file *file, struct address_space *mapping, + loff_t pos, unsigned len, unsigned copied, + struct page *page, void *fsdata) +{ + struct inode *inode = mapping->host; + unsigned start; + + start = pos & (PAGE_CACHE_SIZE - 1); + + if (unlikely(copied < len)) { + /* + * The buffers that were written will now be uptodate, so we + * don't have to worry about a readpage reading them and + * overwriting a partial write. However if we have encountered + * a short write and only partially written into a buffer, it + * will not be marked uptodate, so a readpage might come in and + * destroy our partial write. + * + * Do the simplest thing, and just treat any short write to a + * non uptodate page as a zero-length write, and force the + * caller to redo the whole thing. + */ + if (!PageUptodate(page)) + copied = 0; + + page_zero_new_buffers(page, start+copied, start+len); + } + flush_dcache_page(page); + + /* This could be a short (even 0-length) commit */ + __block_commit_write(inode, page, start, start+copied); + + return copied; +} +EXPORT_SYMBOL(block_write_end); + +int generic_write_end(struct file *file, struct address_space *mapping, + loff_t pos, unsigned len, unsigned copied, + struct page *page, void *fsdata) +{ + struct inode *inode = mapping->host; + int i_size_changed = 0; + + copied = block_write_end(file, mapping, pos, len, copied, page, fsdata); + + /* + * No need to use i_size_read() here, the i_size + * cannot change under us because we hold i_mutex. + * + * But it's important to update i_size while still holding page lock: + * page writeout could otherwise come in and zero beyond i_size. + */ + if (pos+copied > inode->i_size) { + i_size_write(inode, pos+copied); + i_size_changed = 1; + } + + unlock_page(page); + page_cache_release(page); + + /* + * Don't mark the inode dirty under page lock. First, it unnecessarily + * makes the holding time of page lock longer. Second, it forces lock + * ordering of page lock and transaction start for journaling + * filesystems. + */ + if (i_size_changed) + mark_inode_dirty(inode); + + return copied; +} +EXPORT_SYMBOL(generic_write_end); + +/* + * block_is_partially_uptodate checks whether buffers within a page are + * uptodate or not. + * + * Returns true if all buffers which correspond to a file portion + * we want to read are uptodate. + */ +int block_is_partially_uptodate(struct page *page, read_descriptor_t *desc, + unsigned long from) +{ + struct inode *inode = page->mapping->host; + unsigned block_start, block_end, blocksize; + unsigned to; + struct buffer_head *bh, *head; + int ret = 1; + + if (!page_has_buffers(page)) + return 0; + + blocksize = 1 << inode->i_blkbits; + to = min_t(unsigned, PAGE_CACHE_SIZE - from, desc->count); + to = from + to; + if (from < blocksize && to > PAGE_CACHE_SIZE - blocksize) + return 0; + + head = page_buffers(page); + bh = head; + block_start = 0; + do { + block_end = block_start + blocksize; + if (block_end > from && block_start < to) { + if (!buffer_uptodate(bh)) { + ret = 0; + break; + } + if (block_end >= to) + break; + } + block_start = block_end; + bh = bh->b_this_page; + } while (bh != head); + + return ret; +} +EXPORT_SYMBOL(block_is_partially_uptodate); + +/* + * Generic "read page" function for block devices that have the normal + * get_block functionality. This is most of the block device filesystems. + * Reads the page asynchronously --- the unlock_buffer() and + * set/clear_buffer_uptodate() functions propagate buffer state into the + * page struct once IO has completed. + */ +int block_read_full_page(struct page *page, get_block_t *get_block) +{ + struct inode *inode = page->mapping->host; + sector_t iblock, lblock; + struct buffer_head *bh, *head, *arr[MAX_BUF_PER_PAGE]; + unsigned int blocksize; + int nr, i; + int fully_mapped = 1; + + BUG_ON(!PageLocked(page)); + blocksize = 1 << inode->i_blkbits; + if (!page_has_buffers(page)) + create_empty_buffers(page, blocksize, 0); + head = page_buffers(page); + + iblock = (sector_t)page->index << (PAGE_CACHE_SHIFT - inode->i_blkbits); + lblock = (i_size_read(inode)+blocksize-1) >> inode->i_blkbits; + bh = head; + nr = 0; + i = 0; + + do { + if (buffer_uptodate(bh)) + continue; + + if (!buffer_mapped(bh)) { + int err = 0; + + fully_mapped = 0; + if (iblock < lblock) { + WARN_ON(bh->b_size != blocksize); + err = get_block(inode, iblock, bh, 0); + if (err) + SetPageError(page); + } + if (!buffer_mapped(bh)) { + zero_user(page, i * blocksize, blocksize); + if (!err) + set_buffer_uptodate(bh); + continue; + } + /* + * get_block() might have updated the buffer + * synchronously + */ + if (buffer_uptodate(bh)) + continue; + } + arr[nr++] = bh; + } while (i++, iblock++, (bh = bh->b_this_page) != head); + + if (fully_mapped) + SetPageMappedToDisk(page); + + if (!nr) { + /* + * All buffers are uptodate - we can set the page uptodate + * as well. But not if get_block() returned an error. + */ + if (!PageError(page)) + SetPageUptodate(page); + unlock_page(page); + return 0; + } + + /* Stage two: lock the buffers */ + for (i = 0; i < nr; i++) { + bh = arr[i]; + lock_buffer(bh); + mark_buffer_async_read(bh); + } + + /* + * Stage 3: start the IO. Check for uptodateness + * inside the buffer lock in case another process reading + * the underlying blockdev brought it uptodate (the sct fix). + */ + for (i = 0; i < nr; i++) { + bh = arr[i]; + if (buffer_uptodate(bh)) + end_buffer_async_read(bh, 1); + else + submit_bh(READ, bh); + } + return 0; +} + +/* utility function for filesystems that need to do work on expanding + * truncates. Uses filesystem pagecache writes to allow the filesystem to + * deal with the hole. + */ +int generic_cont_expand_simple(struct inode *inode, loff_t size) +{ + struct address_space *mapping = inode->i_mapping; + struct page *page; + void *fsdata; + unsigned long limit; + int err; + + err = -EFBIG; + limit = current->signal->rlim[RLIMIT_FSIZE].rlim_cur; + if (limit != RLIM_INFINITY && size > (loff_t)limit) { + send_sig(SIGXFSZ, current, 0); + goto out; + } + if (size > inode->i_sb->s_maxbytes) + goto out; + + err = pagecache_write_begin(NULL, mapping, size, 0, + AOP_FLAG_UNINTERRUPTIBLE|AOP_FLAG_CONT_EXPAND, + &page, &fsdata); + if (err) + goto out; + + err = pagecache_write_end(NULL, mapping, size, 0, 0, page, fsdata); + BUG_ON(err > 0); + +out: + return err; +} + +static int cont_expand_zero(struct file *file, struct address_space *mapping, + loff_t pos, loff_t *bytes) +{ + struct inode *inode = mapping->host; + unsigned blocksize = 1 << inode->i_blkbits; + struct page *page; + void *fsdata; + pgoff_t index, curidx; + loff_t curpos; + unsigned zerofrom, offset, len; + int err = 0; + + index = pos >> PAGE_CACHE_SHIFT; + offset = pos & ~PAGE_CACHE_MASK; + + while (index > (curidx = (curpos = *bytes)>>PAGE_CACHE_SHIFT)) { + zerofrom = curpos & ~PAGE_CACHE_MASK; + if (zerofrom & (blocksize-1)) { + *bytes |= (blocksize-1); + (*bytes)++; + } + len = PAGE_CACHE_SIZE - zerofrom; + + err = pagecache_write_begin(file, mapping, curpos, len, + AOP_FLAG_UNINTERRUPTIBLE, + &page, &fsdata); + if (err) + goto out; + zero_user(page, zerofrom, len); + err = pagecache_write_end(file, mapping, curpos, len, len, + page, fsdata); + if (err < 0) + goto out; + BUG_ON(err != len); + err = 0; + + balance_dirty_pages_ratelimited(mapping); + } + + /* page covers the boundary, find the boundary offset */ + if (index == curidx) { + zerofrom = curpos & ~PAGE_CACHE_MASK; + /* if we will expand the thing last block will be filled */ + if (offset <= zerofrom) { + goto out; + } + if (zerofrom & (blocksize-1)) { + *bytes |= (blocksize-1); + (*bytes)++; + } + len = offset - zerofrom; + + err = pagecache_write_begin(file, mapping, curpos, len, + AOP_FLAG_UNINTERRUPTIBLE, + &page, &fsdata); + if (err) + goto out; + zero_user(page, zerofrom, len); + err = pagecache_write_end(file, mapping, curpos, len, len, + page, fsdata); + if (err < 0) + goto out; + BUG_ON(err != len); + err = 0; + } +out: + return err; +} + +/* + * For moronic filesystems that do not allow holes in file. + * We may have to extend the file. + */ +int cont_write_begin(struct file *file, struct address_space *mapping, + loff_t pos, unsigned len, unsigned flags, + struct page **pagep, void **fsdata, + get_block_t *get_block, loff_t *bytes) +{ + struct inode *inode = mapping->host; + unsigned blocksize = 1 << inode->i_blkbits; + unsigned zerofrom; + int err; + + err = cont_expand_zero(file, mapping, pos, bytes); + if (err) + goto out; + + zerofrom = *bytes & ~PAGE_CACHE_MASK; + if (pos+len > *bytes && zerofrom & (blocksize-1)) { + *bytes |= (blocksize-1); + (*bytes)++; + } + + *pagep = NULL; + err = block_write_begin(file, mapping, pos, len, + flags, pagep, fsdata, get_block); +out: + return err; +} + +int block_prepare_write(struct page *page, unsigned from, unsigned to, + get_block_t *get_block) +{ + struct inode *inode = page->mapping->host; + int err = __block_prepare_write(inode, page, from, to, get_block); + if (err) + ClearPageUptodate(page); + return err; +} + +int block_commit_write(struct page *page, unsigned from, unsigned to) +{ + struct inode *inode = page->mapping->host; + __block_commit_write(inode,page,from,to); + return 0; +} + +/* + * block_page_mkwrite() is not allowed to change the file size as it gets + * called from a page fault handler when a page is first dirtied. Hence we must + * be careful to check for EOF conditions here. We set the page up correctly + * for a written page which means we get ENOSPC checking when writing into + * holes and correct delalloc and unwritten extent mapping on filesystems that + * support these features. + * + * We are not allowed to take the i_mutex here so we have to play games to + * protect against truncate races as the page could now be beyond EOF. Because + * vmtruncate() writes the inode size before removing pages, once we have the + * page lock we can determine safely if the page is beyond EOF. If it is not + * beyond EOF, then the page is guaranteed safe against truncation until we + * unlock the page. + */ +int +block_page_mkwrite(struct vm_area_struct *vma, struct page *page, + get_block_t get_block) +{ + struct inode *inode = vma->vm_file->f_path.dentry->d_inode; + unsigned long end; + loff_t size; + int ret = -EINVAL; + + lock_page(page); + size = i_size_read(inode); + if ((page->mapping != inode->i_mapping) || + (page_offset(page) > size)) { + /* page got truncated out from underneath us */ + goto out_unlock; + } + + /* page is wholly or partially inside EOF */ + if (((page->index + 1) << PAGE_CACHE_SHIFT) > size) + end = size & ~PAGE_CACHE_MASK; + else + end = PAGE_CACHE_SIZE; + + ret = block_prepare_write(page, 0, end, get_block); + if (!ret) + ret = block_commit_write(page, 0, end); + +out_unlock: + unlock_page(page); + return ret; +} + +/* + * nobh_write_begin()'s prereads are special: the buffer_heads are freed + * immediately, while under the page lock. So it needs a special end_io + * handler which does not touch the bh after unlocking it. + */ +static void end_buffer_read_nobh(struct buffer_head *bh, int uptodate) +{ + __end_buffer_read_notouch(bh, uptodate); +} + +/* + * Attach the singly-linked list of buffers created by nobh_write_begin, to + * the page (converting it to circular linked list and taking care of page + * dirty races). + */ +static void attach_nobh_buffers(struct page *page, struct buffer_head *head) +{ + struct buffer_head *bh; + + BUG_ON(!PageLocked(page)); + + spin_lock(&page->mapping->private_lock); + bh = head; + do { + if (PageDirty(page)) + set_buffer_dirty(bh); + if (!bh->b_this_page) + bh->b_this_page = head; + bh = bh->b_this_page; + } while (bh != head); + attach_page_buffers(page, head); + spin_unlock(&page->mapping->private_lock); +} + +/* + * On entry, the page is fully not uptodate. + * On exit the page is fully uptodate in the areas outside (from,to) + */ +int nobh_write_begin(struct file *file, struct address_space *mapping, + loff_t pos, unsigned len, unsigned flags, + struct page **pagep, void **fsdata, + get_block_t *get_block) +{ + struct inode *inode = mapping->host; + const unsigned blkbits = inode->i_blkbits; + const unsigned blocksize = 1 << blkbits; + struct buffer_head *head, *bh; + struct page *page; + pgoff_t index; + unsigned from, to; + unsigned block_in_page; + unsigned block_start, block_end; + sector_t block_in_file; + int nr_reads = 0; + int ret = 0; + int is_mapped_to_disk = 1; + + index = pos >> PAGE_CACHE_SHIFT; + from = pos & (PAGE_CACHE_SIZE - 1); + to = from + len; + + page = grab_cache_page_write_begin(mapping, index, flags); + if (!page) + return -ENOMEM; + *pagep = page; + *fsdata = NULL; + + if (page_has_buffers(page)) { + unlock_page(page); + page_cache_release(page); + *pagep = NULL; + return block_write_begin(file, mapping, pos, len, flags, pagep, + fsdata, get_block); + } + + if (PageMappedToDisk(page)) + return 0; + + /* + * Allocate buffers so that we can keep track of state, and potentially + * attach them to the page if an error occurs. In the common case of + * no error, they will just be freed again without ever being attached + * to the page (which is all OK, because we're under the page lock). + * + * Be careful: the buffer linked list is a NULL terminated one, rather + * than the circular one we're used to. + */ + head = alloc_page_buffers(page, blocksize, 0); + if (!head) { + ret = -ENOMEM; + goto out_release; + } + + block_in_file = (sector_t)page->index << (PAGE_CACHE_SHIFT - blkbits); + + /* + * We loop across all blocks in the page, whether or not they are + * part of the affected region. This is so we can discover if the + * page is fully mapped-to-disk. + */ + for (block_start = 0, block_in_page = 0, bh = head; + block_start < PAGE_CACHE_SIZE; + block_in_page++, block_start += blocksize, bh = bh->b_this_page) { + int create; + + block_end = block_start + blocksize; + bh->b_state = 0; + create = 1; + if (block_start >= to) + create = 0; + ret = get_block(inode, block_in_file + block_in_page, + bh, create); + if (ret) + goto failed; + if (!buffer_mapped(bh)) + is_mapped_to_disk = 0; + if (buffer_new(bh)) + unmap_underlying_metadata(bh->b_bdev, bh->b_blocknr); + if (PageUptodate(page)) { + set_buffer_uptodate(bh); + continue; + } + if (buffer_new(bh) || !buffer_mapped(bh)) { + zero_user_segments(page, block_start, from, + to, block_end); + continue; + } + if (buffer_uptodate(bh)) + continue; /* reiserfs does this */ + if (block_start < from || block_end > to) { + lock_buffer(bh); + bh->b_end_io = end_buffer_read_nobh; + submit_bh(READ, bh); + nr_reads++; + } + } + + if (nr_reads) { + /* + * The page is locked, so these buffers are protected from + * any VM or truncate activity. Hence we don't need to care + * for the buffer_head refcounts. + */ + for (bh = head; bh; bh = bh->b_this_page) { + wait_on_buffer(bh); + if (!buffer_uptodate(bh)) + ret = -EIO; + } + if (ret) + goto failed; + } + + if (is_mapped_to_disk) + SetPageMappedToDisk(page); + + *fsdata = head; /* to be released by nobh_write_end */ + + return 0; + +failed: + BUG_ON(!ret); + /* + * Error recovery is a bit difficult. We need to zero out blocks that + * were newly allocated, and dirty them to ensure they get written out. + * Buffers need to be attached to the page at this point, otherwise + * the handling of potential IO errors during writeout would be hard + * (could try doing synchronous writeout, but what if that fails too?) + */ + attach_nobh_buffers(page, head); + page_zero_new_buffers(page, from, to); + +out_release: + unlock_page(page); + page_cache_release(page); + *pagep = NULL; + + if (pos + len > inode->i_size) + vmtruncate(inode, inode->i_size); + + return ret; +} +EXPORT_SYMBOL(nobh_write_begin); + +int nobh_write_end(struct file *file, struct address_space *mapping, + loff_t pos, unsigned len, unsigned copied, + struct page *page, void *fsdata) +{ + struct inode *inode = page->mapping->host; + struct buffer_head *head = fsdata; + struct buffer_head *bh; + BUG_ON(fsdata != NULL && page_has_buffers(page)); + + if (unlikely(copied < len) && head) + attach_nobh_buffers(page, head); + if (page_has_buffers(page)) + return generic_write_end(file, mapping, pos, len, + copied, page, fsdata); + + SetPageUptodate(page); + set_page_dirty(page); + if (pos+copied > inode->i_size) { + i_size_write(inode, pos+copied); + mark_inode_dirty(inode); + } + + unlock_page(page); + page_cache_release(page); + + while (head) { + bh = head; + head = head->b_this_page; + free_buffer_head(bh); + } + + return copied; +} +EXPORT_SYMBOL(nobh_write_end); + +/* + * nobh_writepage() - based on block_full_write_page() except + * that it tries to operate without attaching bufferheads to + * the page. + */ +int nobh_writepage(struct page *page, get_block_t *get_block, + struct writeback_control *wbc) +{ + struct inode * const inode = page->mapping->host; + loff_t i_size = i_size_read(inode); + const pgoff_t end_index = i_size >> PAGE_CACHE_SHIFT; + unsigned offset; + int ret; + + /* Is the page fully inside i_size? */ + if (page->index < end_index) + goto out; + + /* Is the page fully outside i_size? (truncate in progress) */ + offset = i_size & (PAGE_CACHE_SIZE-1); + if (page->index >= end_index+1 || !offset) { + /* + * The page may have dirty, unmapped buffers. For example, + * they may have been added in ext3_writepage(). Make them + * freeable here, so the page does not leak. + */ +#if 0 + /* Not really sure about this - do we need this ? */ + if (page->mapping->a_ops->invalidatepage) + page->mapping->a_ops->invalidatepage(page, offset); +#endif + unlock_page(page); + return 0; /* don't care */ + } + + /* + * The page straddles i_size. It must be zeroed out on each and every + * writepage invocation because it may be mmapped. "A file is mapped + * in multiples of the page size. For a file that is not a multiple of + * the page size, the remaining memory is zeroed when mapped, and + * writes to that region are not written out to the file." + */ + zero_user_segment(page, offset, PAGE_CACHE_SIZE); +out: + ret = mpage_writepage(page, get_block, wbc); + if (ret == -EAGAIN) + ret = __block_write_full_page(inode, page, get_block, wbc); + return ret; +} +EXPORT_SYMBOL(nobh_writepage); + +int nobh_truncate_page(struct address_space *mapping, + loff_t from, get_block_t *get_block) +{ + pgoff_t index = from >> PAGE_CACHE_SHIFT; + unsigned offset = from & (PAGE_CACHE_SIZE-1); + unsigned blocksize; + sector_t iblock; + unsigned length, pos; + struct inode *inode = mapping->host; + struct page *page; + struct buffer_head map_bh; + int err; + + blocksize = 1 << inode->i_blkbits; + length = offset & (blocksize - 1); + + /* Block boundary? Nothing to do */ + if (!length) + return 0; + + length = blocksize - length; + iblock = (sector_t)index << (PAGE_CACHE_SHIFT - inode->i_blkbits); + + page = grab_cache_page(mapping, index); + err = -ENOMEM; + if (!page) + goto out; + + if (page_has_buffers(page)) { +has_buffers: + unlock_page(page); + page_cache_release(page); + return block_truncate_page(mapping, from, get_block); + } + + /* Find the buffer that contains "offset" */ + pos = blocksize; + while (offset >= pos) { + iblock++; + pos += blocksize; + } + + err = get_block(inode, iblock, &map_bh, 0); + if (err) + goto unlock; + /* unmapped? It's a hole - nothing to do */ + if (!buffer_mapped(&map_bh)) + goto unlock; + + /* Ok, it's mapped. Make sure it's up-to-date */ + if (!PageUptodate(page)) { + err = mapping->a_ops->readpage(NULL, page); + if (err) { + page_cache_release(page); + goto out; + } + lock_page(page); + if (!PageUptodate(page)) { + err = -EIO; + goto unlock; + } + if (page_has_buffers(page)) + goto has_buffers; + } + zero_user(page, offset, length); + set_page_dirty(page); + err = 0; + +unlock: + unlock_page(page); + page_cache_release(page); +out: + return err; +} +EXPORT_SYMBOL(nobh_truncate_page); + +int block_truncate_page(struct address_space *mapping, + loff_t from, get_block_t *get_block) +{ + pgoff_t index = from >> PAGE_CACHE_SHIFT; + unsigned offset = from & (PAGE_CACHE_SIZE-1); + unsigned blocksize; + sector_t iblock; + unsigned length, pos; + struct inode *inode = mapping->host; + struct page *page; + struct buffer_head *bh; + int err; + + blocksize = 1 << inode->i_blkbits; + length = offset & (blocksize - 1); + + /* Block boundary? Nothing to do */ + if (!length) + return 0; + + length = blocksize - length; + iblock = (sector_t)index << (PAGE_CACHE_SHIFT - inode->i_blkbits); + + page = grab_cache_page(mapping, index); + err = -ENOMEM; + if (!page) + goto out; + + if (!page_has_buffers(page)) + create_empty_buffers(page, blocksize, 0); + + /* Find the buffer that contains "offset" */ + bh = page_buffers(page); + pos = blocksize; + while (offset >= pos) { + bh = bh->b_this_page; + iblock++; + pos += blocksize; + } + + err = 0; + if (!buffer_mapped(bh)) { + WARN_ON(bh->b_size != blocksize); + err = get_block(inode, iblock, bh, 0); + if (err) + goto unlock; + /* unmapped? It's a hole - nothing to do */ + if (!buffer_mapped(bh)) + goto unlock; + } + + /* Ok, it's mapped. Make sure it's up-to-date */ + if (PageUptodate(page)) + set_buffer_uptodate(bh); + + if (!buffer_uptodate(bh) && !buffer_delay(bh) && !buffer_unwritten(bh)) { + err = -EIO; + ll_rw_block(READ, 1, &bh); + wait_on_buffer(bh); + /* Uhhuh. Read error. Complain and punt. */ + if (!buffer_uptodate(bh)) + goto unlock; + } + + zero_user(page, offset, length); + mark_buffer_dirty(bh); + err = 0; + +unlock: + unlock_page(page); + page_cache_release(page); +out: + return err; +} + +/* + * The generic ->writepage function for buffer-backed address_spaces + */ +int block_write_full_page(struct page *page, get_block_t *get_block, + struct writeback_control *wbc) +{ + struct inode * const inode = page->mapping->host; + loff_t i_size = i_size_read(inode); + const pgoff_t end_index = i_size >> PAGE_CACHE_SHIFT; + unsigned offset; + + /* Is the page fully inside i_size? */ + if (page->index < end_index) + return __block_write_full_page(inode, page, get_block, wbc); + + /* Is the page fully outside i_size? (truncate in progress) */ + offset = i_size & (PAGE_CACHE_SIZE-1); + if (page->index >= end_index+1 || !offset) { + /* + * The page may have dirty, unmapped buffers. For example, + * they may have been added in ext3_writepage(). Make them + * freeable here, so the page does not leak. + */ + do_invalidatepage(page, 0); + unlock_page(page); + return 0; /* don't care */ + } + + /* + * The page straddles i_size. It must be zeroed out on each and every + * writepage invokation because it may be mmapped. "A file is mapped + * in multiples of the page size. For a file that is not a multiple of + * the page size, the remaining memory is zeroed when mapped, and + * writes to that region are not written out to the file." + */ + zero_user_segment(page, offset, PAGE_CACHE_SIZE); + return __block_write_full_page(inode, page, get_block, wbc); +} + +sector_t generic_block_bmap(struct address_space *mapping, sector_t block, + get_block_t *get_block) +{ + struct buffer_head tmp; + struct inode *inode = mapping->host; + tmp.b_state = 0; + tmp.b_blocknr = 0; + tmp.b_size = 1 << inode->i_blkbits; + get_block(inode, block, &tmp, 0); + return tmp.b_blocknr; +} + +static void end_bio_bh_io_sync(struct bio *bio, int err) +{ + struct buffer_head *bh = bio->bi_private; + + if (err == -EOPNOTSUPP) { + set_bit(BIO_EOPNOTSUPP, &bio->bi_flags); + set_bit(BH_Eopnotsupp, &bh->b_state); + } + + if (unlikely (test_bit(BIO_QUIET,&bio->bi_flags))) + set_bit(BH_Quiet, &bh->b_state); + + bh->b_end_io(bh, test_bit(BIO_UPTODATE, &bio->bi_flags)); + bio_put(bio); +} + +int submit_bh(int rw, struct buffer_head * bh) +{ + struct bio *bio; + int ret = 0; + + BUG_ON(!buffer_locked(bh)); + BUG_ON(!buffer_mapped(bh)); + BUG_ON(!bh->b_end_io); + + /* + * Mask in barrier bit for a write (could be either a WRITE or a + * WRITE_SYNC + */ + if (buffer_ordered(bh) && (rw & WRITE)) + rw |= WRITE_BARRIER; + + /* + * Only clear out a write error when rewriting + */ + if (test_set_buffer_req(bh) && (rw & WRITE)) + clear_buffer_write_io_error(bh); + + /* + * from here on down, it's all bio -- do the initial mapping, + * submit_bio -> generic_make_request may further map this bio around + */ + bio = bio_alloc(GFP_NOIO, 1); + + bio->bi_sector = bh->b_blocknr * (bh->b_size >> 9); + bio->bi_bdev = bh->b_bdev; + bio->bi_io_vec[0].bv_page = bh->b_page; + bio->bi_io_vec[0].bv_len = bh->b_size; + bio->bi_io_vec[0].bv_offset = bh_offset(bh); + + bio->bi_vcnt = 1; + bio->bi_idx = 0; + bio->bi_size = bh->b_size; + + bio->bi_end_io = end_bio_bh_io_sync; + bio->bi_private = bh; + + bio_get(bio); + submit_bio(rw, bio); + + if (bio_flagged(bio, BIO_EOPNOTSUPP)) + ret = -EOPNOTSUPP; + + bio_put(bio); + return ret; +} + +/** + * ll_rw_block: low-level access to block devices (DEPRECATED) + * @rw: whether to %READ or %WRITE or %SWRITE or maybe %READA (readahead) + * @nr: number of &struct buffer_heads in the array + * @bhs: array of pointers to &struct buffer_head + * + * ll_rw_block() takes an array of pointers to &struct buffer_heads, and + * requests an I/O operation on them, either a %READ or a %WRITE. The third + * %SWRITE is like %WRITE only we make sure that the *current* data in buffers + * are sent to disk. The fourth %READA option is described in the documentation + * for generic_make_request() which ll_rw_block() calls. + * + * This function drops any buffer that it cannot get a lock on (with the + * BH_Lock state bit) unless SWRITE is required, any buffer that appears to be + * clean when doing a write request, and any buffer that appears to be + * up-to-date when doing read request. Further it marks as clean buffers that + * are processed for writing (the buffer cache won't assume that they are + * actually clean until the buffer gets unlocked). + * + * ll_rw_block sets b_end_io to simple completion handler that marks + * the buffer up-to-date (if approriate), unlocks the buffer and wakes + * any waiters. + * + * All of the buffers must be for the same device, and must also be a + * multiple of the current approved size for the device. + */ +void ll_rw_block(int rw, int nr, struct buffer_head *bhs[]) +{ + int i; + + for (i = 0; i < nr; i++) { + struct buffer_head *bh = bhs[i]; + + if (rw == SWRITE || rw == SWRITE_SYNC) + lock_buffer(bh); + else if (!trylock_buffer(bh)) + continue; + + if (rw == WRITE || rw == SWRITE || rw == SWRITE_SYNC) { + if (test_clear_buffer_dirty(bh)) { + bh->b_end_io = end_buffer_write_sync; + get_bh(bh); + if (rw == SWRITE_SYNC) + submit_bh(WRITE_SYNC, bh); + else + submit_bh(WRITE, bh); + continue; + } + } else { + if (!buffer_uptodate(bh)) { + bh->b_end_io = end_buffer_read_sync; + get_bh(bh); + submit_bh(rw, bh); + continue; + } + } + unlock_buffer(bh); + } +} + +/* + * For a data-integrity writeout, we need to wait upon any in-progress I/O + * and then start new I/O and then wait upon it. The caller must have a ref on + * the buffer_head. + */ +int sync_dirty_buffer(struct buffer_head *bh) +{ + int ret = 0; + + WARN_ON(atomic_read(&bh->b_count) < 1); + lock_buffer(bh); + if (test_clear_buffer_dirty(bh)) { + get_bh(bh); + bh->b_end_io = end_buffer_write_sync; + ret = submit_bh(WRITE, bh); + wait_on_buffer(bh); + if (buffer_eopnotsupp(bh)) { + clear_buffer_eopnotsupp(bh); + ret = -EOPNOTSUPP; + } + if (!ret && !buffer_uptodate(bh)) + ret = -EIO; + } else { + unlock_buffer(bh); + } + return ret; +} + +/* + * try_to_free_buffers() checks if all the buffers on this particular page + * are unused, and releases them if so. + * + * Exclusion against try_to_free_buffers may be obtained by either + * locking the page or by holding its mapping's private_lock. + * + * If the page is dirty but all the buffers are clean then we need to + * be sure to mark the page clean as well. This is because the page + * may be against a block device, and a later reattachment of buffers + * to a dirty page will set *all* buffers dirty. Which would corrupt + * filesystem data on the same device. + * + * The same applies to regular filesystem pages: if all the buffers are + * clean then we set the page clean and proceed. To do that, we require + * total exclusion from __set_page_dirty_buffers(). That is obtained with + * private_lock. + * + * try_to_free_buffers() is non-blocking. + */ +static inline int buffer_busy(struct buffer_head *bh) +{ + return atomic_read(&bh->b_count) | + (bh->b_state & ((1 << BH_Dirty) | (1 << BH_Lock))); +} + +static int +drop_buffers(struct page *page, struct buffer_head **buffers_to_free) +{ + struct buffer_head *head = page_buffers(page); + struct buffer_head *bh; + + bh = head; + do { + if (buffer_write_io_error(bh) && page->mapping) + set_bit(AS_EIO, &page->mapping->flags); + if (buffer_busy(bh)) + goto failed; + bh = bh->b_this_page; + } while (bh != head); + + do { + struct buffer_head *next = bh->b_this_page; + + if (bh->b_assoc_map) + __remove_assoc_queue(bh); + bh = next; + } while (bh != head); + *buffers_to_free = head; + __clear_page_buffers(page); + return 1; +failed: + return 0; +} + +int try_to_free_buffers(struct page *page) +{ + struct address_space * const mapping = page->mapping; + struct buffer_head *buffers_to_free = NULL; + int ret = 0; + + BUG_ON(!PageLocked(page)); + if (PageWriteback(page)) + return 0; + + if (mapping == NULL) { /* can this still happen? */ + ret = drop_buffers(page, &buffers_to_free); + goto out; + } + + spin_lock(&mapping->private_lock); + ret = drop_buffers(page, &buffers_to_free); + + /* + * If the filesystem writes its buffers by hand (eg ext3) + * then we can have clean buffers against a dirty page. We + * clean the page here; otherwise the VM will never notice + * that the filesystem did any IO at all. + * + * Also, during truncate, discard_buffer will have marked all + * the page's buffers clean. We discover that here and clean + * the page also. + * + * private_lock must be held over this entire operation in order + * to synchronise against __set_page_dirty_buffers and prevent the + * dirty bit from being lost. + */ +#ifndef DDE_LINUX + if (ret) + cancel_dirty_page(page, PAGE_CACHE_SIZE); +#endif + spin_unlock(&mapping->private_lock); +out: + if (buffers_to_free) { + struct buffer_head *bh = buffers_to_free; + + do { + struct buffer_head *next = bh->b_this_page; + free_buffer_head(bh); + bh = next; + } while (bh != buffers_to_free); + } + return ret; +} +EXPORT_SYMBOL(try_to_free_buffers); + +void block_sync_page(struct page *page) +{ + struct address_space *mapping; + + smp_mb(); + mapping = page_mapping(page); + if (mapping) + blk_run_backing_dev(mapping->backing_dev_info, page); +} + +/* + * There are no bdflush tunables left. But distributions are + * still running obsolete flush daemons, so we terminate them here. + * + * Use of bdflush() is deprecated and will be removed in a future kernel. + * The `pdflush' kernel threads fully replace bdflush daemons and this call. + */ +SYSCALL_DEFINE2(bdflush, int, func, long, data) +{ + static int msg_count; + + if (!capable(CAP_SYS_ADMIN)) + return -EPERM; + + if (msg_count < 5) { + msg_count++; + printk(KERN_INFO + "warning: process `%s' used the obsolete bdflush" + " system call\n", current->comm); + printk(KERN_INFO "Fix your initscripts?\n"); + } + + if (func == 1) + do_exit(0); + return 0; +} + +/* + * Buffer-head allocation + */ +static struct kmem_cache *bh_cachep; + +/* + * Once the number of bh's in the machine exceeds this level, we start + * stripping them in writeback. + */ +static int max_buffer_heads; + +int buffer_heads_over_limit; + +struct bh_accounting { + int nr; /* Number of live bh's */ + int ratelimit; /* Limit cacheline bouncing */ +}; + +static DEFINE_PER_CPU(struct bh_accounting, bh_accounting) = {0, 0}; + +static void recalc_bh_state(void) +{ + int i; + int tot = 0; + + if (__get_cpu_var(bh_accounting).ratelimit++ < 4096) + return; + __get_cpu_var(bh_accounting).ratelimit = 0; + for_each_online_cpu(i) + tot += per_cpu(bh_accounting, i).nr; + buffer_heads_over_limit = (tot > max_buffer_heads); +} + +struct buffer_head *alloc_buffer_head(gfp_t gfp_flags) +{ + struct buffer_head *ret = kmem_cache_alloc(bh_cachep, gfp_flags); + if (ret) { + INIT_LIST_HEAD(&ret->b_assoc_buffers); + get_cpu_var(bh_accounting).nr++; + recalc_bh_state(); + put_cpu_var(bh_accounting); + } + return ret; +} +EXPORT_SYMBOL(alloc_buffer_head); + +void free_buffer_head(struct buffer_head *bh) +{ + BUG_ON(!list_empty(&bh->b_assoc_buffers)); + kmem_cache_free(bh_cachep, bh); + get_cpu_var(bh_accounting).nr--; + recalc_bh_state(); + put_cpu_var(bh_accounting); +} +EXPORT_SYMBOL(free_buffer_head); + +static void buffer_exit_cpu(int cpu) +{ + int i; + struct bh_lru *b = &per_cpu(bh_lrus, cpu); + + for (i = 0; i < BH_LRU_SIZE; i++) { + brelse(b->bhs[i]); + b->bhs[i] = NULL; + } + get_cpu_var(bh_accounting).nr += per_cpu(bh_accounting, cpu).nr; + per_cpu(bh_accounting, cpu).nr = 0; + put_cpu_var(bh_accounting); +} + +static int buffer_cpu_notify(struct notifier_block *self, + unsigned long action, void *hcpu) +{ + if (action == CPU_DEAD || action == CPU_DEAD_FROZEN) + buffer_exit_cpu((unsigned long)hcpu); + return NOTIFY_OK; +} + +/** + * bh_uptodate_or_lock - Test whether the buffer is uptodate + * @bh: struct buffer_head + * + * Return true if the buffer is up-to-date and false, + * with the buffer locked, if not. + */ +int bh_uptodate_or_lock(struct buffer_head *bh) +{ + if (!buffer_uptodate(bh)) { + lock_buffer(bh); + if (!buffer_uptodate(bh)) + return 0; + unlock_buffer(bh); + } + return 1; +} +EXPORT_SYMBOL(bh_uptodate_or_lock); + +/** + * bh_submit_read - Submit a locked buffer for reading + * @bh: struct buffer_head + * + * Returns zero on success and -EIO on error. + */ +int bh_submit_read(struct buffer_head *bh) +{ + BUG_ON(!buffer_locked(bh)); + + if (buffer_uptodate(bh)) { + unlock_buffer(bh); + return 0; + } + + get_bh(bh); + bh->b_end_io = end_buffer_read_sync; + submit_bh(READ, bh); + wait_on_buffer(bh); + if (buffer_uptodate(bh)) + return 0; + return -EIO; +} +EXPORT_SYMBOL(bh_submit_read); + +static void +init_buffer_head(void *data) +{ + struct buffer_head *bh = data; + + memset(bh, 0, sizeof(*bh)); + INIT_LIST_HEAD(&bh->b_assoc_buffers); +} + +void __init buffer_init(void) +{ + int nrpages; + + bh_cachep = kmem_cache_create("buffer_head", + sizeof(struct buffer_head), 0, + (SLAB_RECLAIM_ACCOUNT|SLAB_PANIC| + SLAB_MEM_SPREAD), + init_buffer_head); + + /* + * Limit the bh occupancy to 10% of ZONE_NORMAL + */ + nrpages = (nr_free_buffer_pages() * 10) / 100; + max_buffer_heads = nrpages * (PAGE_SIZE / sizeof(struct buffer_head)); + hotcpu_notifier(buffer_cpu_notify, 0); +} + +EXPORT_SYMBOL(__bforget); +EXPORT_SYMBOL(__brelse); +EXPORT_SYMBOL(__wait_on_buffer); +EXPORT_SYMBOL(block_commit_write); +EXPORT_SYMBOL(block_prepare_write); +EXPORT_SYMBOL(block_page_mkwrite); +EXPORT_SYMBOL(block_read_full_page); +EXPORT_SYMBOL(block_sync_page); +EXPORT_SYMBOL(block_truncate_page); +EXPORT_SYMBOL(block_write_full_page); +EXPORT_SYMBOL(cont_write_begin); +EXPORT_SYMBOL(end_buffer_read_sync); +EXPORT_SYMBOL(end_buffer_write_sync); +EXPORT_SYMBOL(file_fsync); +EXPORT_SYMBOL(fsync_bdev); +EXPORT_SYMBOL(generic_block_bmap); +EXPORT_SYMBOL(generic_cont_expand_simple); +EXPORT_SYMBOL(init_buffer); +EXPORT_SYMBOL(invalidate_bdev); +EXPORT_SYMBOL(ll_rw_block); +EXPORT_SYMBOL(mark_buffer_dirty); +EXPORT_SYMBOL(submit_bh); +EXPORT_SYMBOL(sync_dirty_buffer); +EXPORT_SYMBOL(unlock_buffer); diff --git a/libdde_linux26/lib/src/fs/.svn/text-base/char_dev.c.svn-base b/libdde_linux26/lib/src/fs/.svn/text-base/char_dev.c.svn-base new file mode 100644 index 00000000..3b8e8b3d --- /dev/null +++ b/libdde_linux26/lib/src/fs/.svn/text-base/char_dev.c.svn-base @@ -0,0 +1,572 @@ +/* + * linux/fs/char_dev.c + * + * Copyright (C) 1991, 1992 Linus Torvalds + */ + +#include <linux/init.h> +#include <linux/fs.h> +#include <linux/kdev_t.h> +#include <linux/slab.h> +#include <linux/string.h> + +#include <linux/major.h> +#include <linux/errno.h> +#include <linux/module.h> +#include <linux/smp_lock.h> +#include <linux/seq_file.h> + +#include <linux/kobject.h> +#include <linux/kobj_map.h> +#include <linux/cdev.h> +#include <linux/mutex.h> +#include <linux/backing-dev.h> + +#ifdef CONFIG_KMOD +#include <linux/kmod.h> +#endif +#include "internal.h" + +#ifdef DDE_LINUX +#include "local.h" +#endif + +/* + * capabilities for /dev/mem, /dev/kmem and similar directly mappable character + * devices + * - permits shared-mmap for read, write and/or exec + * - does not permit private mmap in NOMMU mode (can't do COW) + * - no readahead or I/O queue unplugging required + */ +struct backing_dev_info directly_mappable_cdev_bdi = { + .capabilities = ( +#ifdef CONFIG_MMU + /* permit private copies of the data to be taken */ + BDI_CAP_MAP_COPY | +#endif + /* permit direct mmap, for read, write or exec */ + BDI_CAP_MAP_DIRECT | + BDI_CAP_READ_MAP | BDI_CAP_WRITE_MAP | BDI_CAP_EXEC_MAP), +}; + +static struct kobj_map *cdev_map; + +static DEFINE_MUTEX(chrdevs_lock); + +static struct char_device_struct { + struct char_device_struct *next; + unsigned int major; + unsigned int baseminor; + int minorct; + char name[64]; + struct cdev *cdev; /* will die */ +} *chrdevs[CHRDEV_MAJOR_HASH_SIZE]; + +/* index in the above */ +static inline int major_to_index(int major) +{ + return major % CHRDEV_MAJOR_HASH_SIZE; +} + +#ifdef CONFIG_PROC_FS + +void chrdev_show(struct seq_file *f, off_t offset) +{ + struct char_device_struct *cd; + + if (offset < CHRDEV_MAJOR_HASH_SIZE) { + mutex_lock(&chrdevs_lock); + for (cd = chrdevs[offset]; cd; cd = cd->next) + seq_printf(f, "%3d %s\n", cd->major, cd->name); + mutex_unlock(&chrdevs_lock); + } +} + +#endif /* CONFIG_PROC_FS */ + +/* + * Register a single major with a specified minor range. + * + * If major == 0 this functions will dynamically allocate a major and return + * its number. + * + * If major > 0 this function will attempt to reserve the passed range of + * minors and will return zero on success. + * + * Returns a -ve errno on failure. + */ +static struct char_device_struct * +__register_chrdev_region(unsigned int major, unsigned int baseminor, + int minorct, const char *name) +{ + struct char_device_struct *cd, **cp; + int ret = 0; + int i; + + cd = kzalloc(sizeof(struct char_device_struct), GFP_KERNEL); + if (cd == NULL) + return ERR_PTR(-ENOMEM); + + mutex_lock(&chrdevs_lock); + + /* temporary */ + if (major == 0) { + for (i = ARRAY_SIZE(chrdevs)-1; i > 0; i--) { + if (chrdevs[i] == NULL) + break; + } + + if (i == 0) { + ret = -EBUSY; + goto out; + } + major = i; + ret = major; + } + + cd->major = major; + cd->baseminor = baseminor; + cd->minorct = minorct; + strlcpy(cd->name, name, sizeof(cd->name)); + + i = major_to_index(major); + + for (cp = &chrdevs[i]; *cp; cp = &(*cp)->next) + if ((*cp)->major > major || + ((*cp)->major == major && + (((*cp)->baseminor >= baseminor) || + ((*cp)->baseminor + (*cp)->minorct > baseminor)))) + break; + + /* Check for overlapping minor ranges. */ + if (*cp && (*cp)->major == major) { + int old_min = (*cp)->baseminor; + int old_max = (*cp)->baseminor + (*cp)->minorct - 1; + int new_min = baseminor; + int new_max = baseminor + minorct - 1; + + /* New driver overlaps from the left. */ + if (new_max >= old_min && new_max <= old_max) { + ret = -EBUSY; + goto out; + } + + /* New driver overlaps from the right. */ + if (new_min <= old_max && new_min >= old_min) { + ret = -EBUSY; + goto out; + } + } + + cd->next = *cp; + *cp = cd; + mutex_unlock(&chrdevs_lock); + return cd; +out: + mutex_unlock(&chrdevs_lock); + kfree(cd); + return ERR_PTR(ret); +} + +static struct char_device_struct * +__unregister_chrdev_region(unsigned major, unsigned baseminor, int minorct) +{ + struct char_device_struct *cd = NULL, **cp; + int i = major_to_index(major); + + mutex_lock(&chrdevs_lock); + for (cp = &chrdevs[i]; *cp; cp = &(*cp)->next) + if ((*cp)->major == major && + (*cp)->baseminor == baseminor && + (*cp)->minorct == minorct) + break; + if (*cp) { + cd = *cp; + *cp = cd->next; + } + mutex_unlock(&chrdevs_lock); + return cd; +} + +/** + * register_chrdev_region() - register a range of device numbers + * @from: the first in the desired range of device numbers; must include + * the major number. + * @count: the number of consecutive device numbers required + * @name: the name of the device or driver. + * + * Return value is zero on success, a negative error code on failure. + */ +int register_chrdev_region(dev_t from, unsigned count, const char *name) +{ + struct char_device_struct *cd; + dev_t to = from + count; + dev_t n, next; + + for (n = from; n < to; n = next) { + next = MKDEV(MAJOR(n)+1, 0); + if (next > to) + next = to; + cd = __register_chrdev_region(MAJOR(n), MINOR(n), + next - n, name); + if (IS_ERR(cd)) + goto fail; + } + return 0; +fail: + to = n; + for (n = from; n < to; n = next) { + next = MKDEV(MAJOR(n)+1, 0); + kfree(__unregister_chrdev_region(MAJOR(n), MINOR(n), next - n)); + } + return PTR_ERR(cd); +} + +/** + * alloc_chrdev_region() - register a range of char device numbers + * @dev: output parameter for first assigned number + * @baseminor: first of the requested range of minor numbers + * @count: the number of minor numbers required + * @name: the name of the associated device or driver + * + * Allocates a range of char device numbers. The major number will be + * chosen dynamically, and returned (along with the first minor number) + * in @dev. Returns zero or a negative error code. + */ +int alloc_chrdev_region(dev_t *dev, unsigned baseminor, unsigned count, + const char *name) +{ + struct char_device_struct *cd; + cd = __register_chrdev_region(0, baseminor, count, name); + if (IS_ERR(cd)) + return PTR_ERR(cd); + *dev = MKDEV(cd->major, cd->baseminor); + return 0; +} + +/** + * register_chrdev() - Register a major number for character devices. + * @major: major device number or 0 for dynamic allocation + * @name: name of this range of devices + * @fops: file operations associated with this devices + * + * If @major == 0 this functions will dynamically allocate a major and return + * its number. + * + * If @major > 0 this function will attempt to reserve a device with the given + * major number and will return zero on success. + * + * Returns a -ve errno on failure. + * + * The name of this device has nothing to do with the name of the device in + * /dev. It only helps to keep track of the different owners of devices. If + * your module name has only one type of devices it's ok to use e.g. the name + * of the module here. + * + * This function registers a range of 256 minor numbers. The first minor number + * is 0. + */ +int register_chrdev(unsigned int major, const char *name, + const struct file_operations *fops) +{ + struct char_device_struct *cd; + struct cdev *cdev; + char *s; + int err = -ENOMEM; + + cd = __register_chrdev_region(major, 0, 256, name); + if (IS_ERR(cd)) + return PTR_ERR(cd); + + cdev = cdev_alloc(); + if (!cdev) + goto out2; + + cdev->owner = fops->owner; + cdev->ops = fops; + kobject_set_name(&cdev->kobj, "%s", name); + for (s = strchr(kobject_name(&cdev->kobj),'/'); s; s = strchr(s, '/')) + *s = '!'; + + err = cdev_add(cdev, MKDEV(cd->major, 0), 256); + if (err) + goto out; + + cd->cdev = cdev; + + return major ? 0 : cd->major; +out: + kobject_put(&cdev->kobj); +out2: + kfree(__unregister_chrdev_region(cd->major, 0, 256)); + return err; +} + +/** + * unregister_chrdev_region() - return a range of device numbers + * @from: the first in the range of numbers to unregister + * @count: the number of device numbers to unregister + * + * This function will unregister a range of @count device numbers, + * starting with @from. The caller should normally be the one who + * allocated those numbers in the first place... + */ +void unregister_chrdev_region(dev_t from, unsigned count) +{ + dev_t to = from + count; + dev_t n, next; + + for (n = from; n < to; n = next) { + next = MKDEV(MAJOR(n)+1, 0); + if (next > to) + next = to; + kfree(__unregister_chrdev_region(MAJOR(n), MINOR(n), next - n)); + } +} + +void unregister_chrdev(unsigned int major, const char *name) +{ + struct char_device_struct *cd; + cd = __unregister_chrdev_region(major, 0, 256); + if (cd && cd->cdev) + cdev_del(cd->cdev); + kfree(cd); +} + +static DEFINE_SPINLOCK(cdev_lock); + +static struct kobject *cdev_get(struct cdev *p) +{ + struct module *owner = p->owner; + struct kobject *kobj; + + if (owner && !try_module_get(owner)) + return NULL; + kobj = kobject_get(&p->kobj); + if (!kobj) + module_put(owner); + return kobj; +} + +void cdev_put(struct cdev *p) +{ + if (p) { + struct module *owner = p->owner; + kobject_put(&p->kobj); + module_put(owner); + } +} + +/* + * Called every time a character special file is opened + */ +static int chrdev_open(struct inode *inode, struct file *filp) +{ + struct cdev *p; + struct cdev *new = NULL; + int ret = 0; + + spin_lock(&cdev_lock); + p = inode->i_cdev; + if (!p) { + struct kobject *kobj; + int idx; + spin_unlock(&cdev_lock); + kobj = kobj_lookup(cdev_map, inode->i_rdev, &idx); + if (!kobj) + return -ENXIO; + new = container_of(kobj, struct cdev, kobj); + spin_lock(&cdev_lock); + /* Check i_cdev again in case somebody beat us to it while + we dropped the lock. */ + p = inode->i_cdev; + if (!p) { + inode->i_cdev = p = new; + inode->i_cindex = idx; + list_add(&inode->i_devices, &p->list); + new = NULL; + } else if (!cdev_get(p)) + ret = -ENXIO; + } else if (!cdev_get(p)) + ret = -ENXIO; + spin_unlock(&cdev_lock); + cdev_put(new); + if (ret) + return ret; + + ret = -ENXIO; + filp->f_op = fops_get(p->ops); + if (!filp->f_op) + goto out_cdev_put; + + if (filp->f_op->open) { + ret = filp->f_op->open(inode,filp); + if (ret) + goto out_cdev_put; + } + + return 0; + + out_cdev_put: + cdev_put(p); + return ret; +} + +void cd_forget(struct inode *inode) +{ + spin_lock(&cdev_lock); + list_del_init(&inode->i_devices); + inode->i_cdev = NULL; + spin_unlock(&cdev_lock); +} + +static void cdev_purge(struct cdev *cdev) +{ + spin_lock(&cdev_lock); + while (!list_empty(&cdev->list)) { + struct inode *inode; + inode = container_of(cdev->list.next, struct inode, i_devices); + list_del_init(&inode->i_devices); + inode->i_cdev = NULL; + } + spin_unlock(&cdev_lock); +} + +/* + * Dummy default file-operations: the only thing this does + * is contain the open that then fills in the correct operations + * depending on the special file... + */ +const struct file_operations def_chr_fops = { + .open = chrdev_open, +}; + +static struct kobject *exact_match(dev_t dev, int *part, void *data) +{ + struct cdev *p = data; + return &p->kobj; +} + +static int exact_lock(dev_t dev, void *data) +{ + struct cdev *p = data; + return cdev_get(p) ? 0 : -1; +} + +/** + * cdev_add() - add a char device to the system + * @p: the cdev structure for the device + * @dev: the first device number for which this device is responsible + * @count: the number of consecutive minor numbers corresponding to this + * device + * + * cdev_add() adds the device represented by @p to the system, making it + * live immediately. A negative error code is returned on failure. + */ +int cdev_add(struct cdev *p, dev_t dev, unsigned count) +{ + p->dev = dev; + p->count = count; + return kobj_map(cdev_map, dev, count, NULL, exact_match, exact_lock, p); +} + +static void cdev_unmap(dev_t dev, unsigned count) +{ + kobj_unmap(cdev_map, dev, count); +} + +/** + * cdev_del() - remove a cdev from the system + * @p: the cdev structure to be removed + * + * cdev_del() removes @p from the system, possibly freeing the structure + * itself. + */ +void cdev_del(struct cdev *p) +{ + cdev_unmap(p->dev, p->count); + kobject_put(&p->kobj); +} + + +static void cdev_default_release(struct kobject *kobj) +{ + struct cdev *p = container_of(kobj, struct cdev, kobj); + cdev_purge(p); +} + +static void cdev_dynamic_release(struct kobject *kobj) +{ + struct cdev *p = container_of(kobj, struct cdev, kobj); + cdev_purge(p); + kfree(p); +} + +static struct kobj_type ktype_cdev_default = { + .release = cdev_default_release, +}; + +static struct kobj_type ktype_cdev_dynamic = { + .release = cdev_dynamic_release, +}; + +/** + * cdev_alloc() - allocate a cdev structure + * + * Allocates and returns a cdev structure, or NULL on failure. + */ +struct cdev *cdev_alloc(void) +{ + struct cdev *p = kzalloc(sizeof(struct cdev), GFP_KERNEL); + if (p) { + INIT_LIST_HEAD(&p->list); + kobject_init(&p->kobj, &ktype_cdev_dynamic); + } + return p; +} + +/** + * cdev_init() - initialize a cdev structure + * @cdev: the structure to initialize + * @fops: the file_operations for this device + * + * Initializes @cdev, remembering @fops, making it ready to add to the + * system with cdev_add(). + */ +void cdev_init(struct cdev *cdev, const struct file_operations *fops) +{ + memset(cdev, 0, sizeof *cdev); + INIT_LIST_HEAD(&cdev->list); + kobject_init(&cdev->kobj, &ktype_cdev_default); + cdev->ops = fops; +} + +static struct kobject *base_probe(dev_t dev, int *part, void *data) +{ + if (request_module("char-major-%d-%d", MAJOR(dev), MINOR(dev)) > 0) + /* Make old-style 2.4 aliases work */ + request_module("char-major-%d", MAJOR(dev)); + return NULL; +} + +void __init chrdev_init(void) +{ + cdev_map = kobj_map_init(base_probe, &chrdevs_lock); + bdi_init(&directly_mappable_cdev_bdi); +} + +#ifndef LIBINPUT +core_initcall(chrdev_init); +#endif + +/* Let modules do char dev stuff */ +EXPORT_SYMBOL(register_chrdev_region); +EXPORT_SYMBOL(unregister_chrdev_region); +EXPORT_SYMBOL(alloc_chrdev_region); +EXPORT_SYMBOL(cdev_init); +EXPORT_SYMBOL(cdev_alloc); +EXPORT_SYMBOL(cdev_del); +EXPORT_SYMBOL(cdev_add); +EXPORT_SYMBOL(register_chrdev); +EXPORT_SYMBOL(unregister_chrdev); +EXPORT_SYMBOL(directly_mappable_cdev_bdi); diff --git a/libdde_linux26/lib/src/fs/block_dev.c b/libdde_linux26/lib/src/fs/block_dev.c new file mode 100644 index 00000000..4c4c2f64 --- /dev/null +++ b/libdde_linux26/lib/src/fs/block_dev.c @@ -0,0 +1,1422 @@ +/* + * linux/fs/block_dev.c + * + * Copyright (C) 1991, 1992 Linus Torvalds + * Copyright (C) 2001 Andrea Arcangeli <andrea@suse.de> SuSE + */ + +#include <linux/init.h> +#include <linux/mm.h> +#include <linux/fcntl.h> +#include <linux/slab.h> +#include <linux/kmod.h> +#include <linux/major.h> +#include <linux/smp_lock.h> +#include <linux/device_cgroup.h> +#include <linux/highmem.h> +#include <linux/blkdev.h> +#include <linux/module.h> +#include <linux/blkpg.h> +#include <linux/buffer_head.h> +#include <linux/writeback.h> +#include <linux/mpage.h> +#include <linux/mount.h> +#include <linux/uio.h> +#include <linux/namei.h> +#include <linux/log2.h> +#include <asm/uaccess.h> +#include "internal.h" + +#ifdef DDE_LINUX +#include "local.h" +#endif + +struct bdev_inode { + struct block_device bdev; + struct inode vfs_inode; +}; + +static const struct address_space_operations def_blk_aops; + +static inline struct bdev_inode *BDEV_I(struct inode *inode) +{ + return container_of(inode, struct bdev_inode, vfs_inode); +} + +inline struct block_device *I_BDEV(struct inode *inode) +{ + return &BDEV_I(inode)->bdev; +} + +EXPORT_SYMBOL(I_BDEV); + +static sector_t max_block(struct block_device *bdev) +{ + sector_t retval = ~((sector_t)0); + loff_t sz = i_size_read(bdev->bd_inode); + + if (sz) { + unsigned int size = block_size(bdev); + unsigned int sizebits = blksize_bits(size); + retval = (sz >> sizebits); + } + return retval; +} + +/* Kill _all_ buffers and pagecache , dirty or not.. */ +static void kill_bdev(struct block_device *bdev) +{ + if (bdev->bd_inode->i_mapping->nrpages == 0) + return; + invalidate_bh_lrus(); + truncate_inode_pages(bdev->bd_inode->i_mapping, 0); +} + +int set_blocksize(struct block_device *bdev, int size) +{ + /* Size must be a power of two, and between 512 and PAGE_SIZE */ + if (size > PAGE_SIZE || size < 512 || !is_power_of_2(size)) + return -EINVAL; + + /* Size cannot be smaller than the size supported by the device */ + if (size < bdev_hardsect_size(bdev)) + return -EINVAL; + + /* Don't change the size if it is same as current */ + if (bdev->bd_block_size != size) { + sync_blockdev(bdev); + bdev->bd_block_size = size; + bdev->bd_inode->i_blkbits = blksize_bits(size); + kill_bdev(bdev); + } + return 0; +} + +EXPORT_SYMBOL(set_blocksize); + +int sb_set_blocksize(struct super_block *sb, int size) +{ + if (set_blocksize(sb->s_bdev, size)) + return 0; + /* If we get here, we know size is power of two + * and it's value is between 512 and PAGE_SIZE */ + sb->s_blocksize = size; + sb->s_blocksize_bits = blksize_bits(size); + return sb->s_blocksize; +} + +EXPORT_SYMBOL(sb_set_blocksize); + +int sb_min_blocksize(struct super_block *sb, int size) +{ + int minsize = bdev_hardsect_size(sb->s_bdev); + if (size < minsize) + size = minsize; + return sb_set_blocksize(sb, size); +} + +EXPORT_SYMBOL(sb_min_blocksize); + +static int +blkdev_get_block(struct inode *inode, sector_t iblock, + struct buffer_head *bh, int create) +{ + if (iblock >= max_block(I_BDEV(inode))) { + if (create) + return -EIO; + + /* + * for reads, we're just trying to fill a partial page. + * return a hole, they will have to call get_block again + * before they can fill it, and they will get -EIO at that + * time + */ + return 0; + } + bh->b_bdev = I_BDEV(inode); + bh->b_blocknr = iblock; + set_buffer_mapped(bh); + return 0; +} + +static int +blkdev_get_blocks(struct inode *inode, sector_t iblock, + struct buffer_head *bh, int create) +{ + sector_t end_block = max_block(I_BDEV(inode)); + unsigned long max_blocks = bh->b_size >> inode->i_blkbits; + + if ((iblock + max_blocks) > end_block) { + max_blocks = end_block - iblock; + if ((long)max_blocks <= 0) { + if (create) + return -EIO; /* write fully beyond EOF */ + /* + * It is a read which is fully beyond EOF. We return + * a !buffer_mapped buffer + */ + max_blocks = 0; + } + } + + bh->b_bdev = I_BDEV(inode); + bh->b_blocknr = iblock; + bh->b_size = max_blocks << inode->i_blkbits; + if (max_blocks) + set_buffer_mapped(bh); + return 0; +} + +static ssize_t +blkdev_direct_IO(int rw, struct kiocb *iocb, const struct iovec *iov, + loff_t offset, unsigned long nr_segs) +{ + struct file *file = iocb->ki_filp; + struct inode *inode = file->f_mapping->host; + +#ifndef DDE_LINUX + return blockdev_direct_IO_no_locking(rw, iocb, inode, I_BDEV(inode), + iov, offset, nr_segs, blkdev_get_blocks, NULL); +#else + WARN_UNIMPL; + return 0; +#endif /* DDE_LINUX */ +} + +static int blkdev_writepage(struct page *page, struct writeback_control *wbc) +{ + return block_write_full_page(page, blkdev_get_block, wbc); +} + +static int blkdev_readpage(struct file * file, struct page * page) +{ + return block_read_full_page(page, blkdev_get_block); +} + +static int blkdev_write_begin(struct file *file, struct address_space *mapping, + loff_t pos, unsigned len, unsigned flags, + struct page **pagep, void **fsdata) +{ + *pagep = NULL; + return block_write_begin(file, mapping, pos, len, flags, pagep, fsdata, + blkdev_get_block); +} + +static int blkdev_write_end(struct file *file, struct address_space *mapping, + loff_t pos, unsigned len, unsigned copied, + struct page *page, void *fsdata) +{ + int ret; + ret = block_write_end(file, mapping, pos, len, copied, page, fsdata); + + unlock_page(page); + page_cache_release(page); + + return ret; +} + +/* + * private llseek: + * for a block special file file->f_path.dentry->d_inode->i_size is zero + * so we compute the size by hand (just as in block_read/write above) + */ +static loff_t block_llseek(struct file *file, loff_t offset, int origin) +{ + struct inode *bd_inode = file->f_mapping->host; + loff_t size; + loff_t retval; + + mutex_lock(&bd_inode->i_mutex); + size = i_size_read(bd_inode); + + switch (origin) { + case 2: + offset += size; + break; + case 1: + offset += file->f_pos; + } + retval = -EINVAL; + if (offset >= 0 && offset <= size) { + if (offset != file->f_pos) { + file->f_pos = offset; + } + retval = offset; + } + mutex_unlock(&bd_inode->i_mutex); + return retval; +} + +/* + * Filp is never NULL; the only case when ->fsync() is called with + * NULL first argument is nfsd_sync_dir() and that's not a directory. + */ + +static int block_fsync(struct file *filp, struct dentry *dentry, int datasync) +{ + return sync_blockdev(I_BDEV(filp->f_mapping->host)); +} + +/* + * pseudo-fs + */ + +static __cacheline_aligned_in_smp DEFINE_SPINLOCK(bdev_lock); +static struct kmem_cache * bdev_cachep __read_mostly; + +static struct inode *bdev_alloc_inode(struct super_block *sb) +{ + struct bdev_inode *ei = kmem_cache_alloc(bdev_cachep, GFP_KERNEL); + if (!ei) + return NULL; + return &ei->vfs_inode; +} + +static void bdev_destroy_inode(struct inode *inode) +{ + struct bdev_inode *bdi = BDEV_I(inode); + + bdi->bdev.bd_inode_backing_dev_info = NULL; + kmem_cache_free(bdev_cachep, bdi); +} + +static void init_once(void *foo) +{ + struct bdev_inode *ei = (struct bdev_inode *) foo; + struct block_device *bdev = &ei->bdev; + + memset(bdev, 0, sizeof(*bdev)); + mutex_init(&bdev->bd_mutex); + sema_init(&bdev->bd_mount_sem, 1); + INIT_LIST_HEAD(&bdev->bd_inodes); + INIT_LIST_HEAD(&bdev->bd_list); +#ifdef CONFIG_SYSFS + INIT_LIST_HEAD(&bdev->bd_holder_list); +#endif + inode_init_once(&ei->vfs_inode); + /* Initialize mutex for freeze. */ + mutex_init(&bdev->bd_fsfreeze_mutex); +} + +static inline void __bd_forget(struct inode *inode) +{ + list_del_init(&inode->i_devices); + inode->i_bdev = NULL; + inode->i_mapping = &inode->i_data; +} + +static void bdev_clear_inode(struct inode *inode) +{ + struct block_device *bdev = &BDEV_I(inode)->bdev; + struct list_head *p; + spin_lock(&bdev_lock); + while ( (p = bdev->bd_inodes.next) != &bdev->bd_inodes ) { + __bd_forget(list_entry(p, struct inode, i_devices)); + } + list_del_init(&bdev->bd_list); + spin_unlock(&bdev_lock); +} + +static const struct super_operations bdev_sops = { + .statfs = simple_statfs, + .alloc_inode = bdev_alloc_inode, + .destroy_inode = bdev_destroy_inode, + .drop_inode = generic_delete_inode, + .clear_inode = bdev_clear_inode, +}; + +static int bd_get_sb(struct file_system_type *fs_type, + int flags, const char *dev_name, void *data, struct vfsmount *mnt) +{ + return get_sb_pseudo(fs_type, "bdev:", &bdev_sops, 0x62646576, mnt); +} + +static struct file_system_type bd_type = { + .name = "bdev", + .get_sb = bd_get_sb, + .kill_sb = kill_anon_super, +}; + +struct super_block *blockdev_superblock __read_mostly; + +void __init bdev_cache_init(void) +{ + int err; + struct vfsmount *bd_mnt; + + bdev_cachep = kmem_cache_create("bdev_cache", sizeof(struct bdev_inode), + 0, (SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT| + SLAB_MEM_SPREAD|SLAB_PANIC), + init_once); + err = register_filesystem(&bd_type); + if (err) + panic("Cannot register bdev pseudo-fs"); + bd_mnt = kern_mount(&bd_type); + if (IS_ERR(bd_mnt)) + panic("Cannot create bdev pseudo-fs"); + blockdev_superblock = bd_mnt->mnt_sb; /* For writeback */ +} + +/* + * Most likely _very_ bad one - but then it's hardly critical for small + * /dev and can be fixed when somebody will need really large one. + * Keep in mind that it will be fed through icache hash function too. + */ +static inline unsigned long hash(dev_t dev) +{ + return MAJOR(dev)+MINOR(dev); +} + +static int bdev_test(struct inode *inode, void *data) +{ + return BDEV_I(inode)->bdev.bd_dev == *(dev_t *)data; +} + +static int bdev_set(struct inode *inode, void *data) +{ + BDEV_I(inode)->bdev.bd_dev = *(dev_t *)data; + return 0; +} + +static LIST_HEAD(all_bdevs); + +struct block_device *bdget(dev_t dev) +{ + struct block_device *bdev; + struct inode *inode; + + printk_all_partitions(); + + inode = iget5_locked(blockdev_superblock, hash(dev), + bdev_test, bdev_set, &dev); + + if (!inode) + return NULL; + + bdev = &BDEV_I(inode)->bdev; + + if (inode->i_state & I_NEW) { + bdev->bd_contains = NULL; + bdev->bd_inode = inode; + bdev->bd_block_size = (1 << inode->i_blkbits); + bdev->bd_part_count = 0; + bdev->bd_invalidated = 0; + inode->i_mode = S_IFBLK; + inode->i_rdev = dev; + inode->i_bdev = bdev; + inode->i_data.a_ops = &def_blk_aops; + mapping_set_gfp_mask(&inode->i_data, GFP_USER); + inode->i_data.backing_dev_info = &default_backing_dev_info; + spin_lock(&bdev_lock); + list_add(&bdev->bd_list, &all_bdevs); + spin_unlock(&bdev_lock); + unlock_new_inode(inode); + } + return bdev; +} + +EXPORT_SYMBOL(bdget); + +long nr_blockdev_pages(void) +{ + struct block_device *bdev; + long ret = 0; + spin_lock(&bdev_lock); + list_for_each_entry(bdev, &all_bdevs, bd_list) { + ret += bdev->bd_inode->i_mapping->nrpages; + } + spin_unlock(&bdev_lock); + return ret; +} + +void bdput(struct block_device *bdev) +{ + iput(bdev->bd_inode); +} + +EXPORT_SYMBOL(bdput); + +static struct block_device *bd_acquire(struct inode *inode) +{ + struct block_device *bdev; + + spin_lock(&bdev_lock); + bdev = inode->i_bdev; + if (bdev) { + atomic_inc(&bdev->bd_inode->i_count); + spin_unlock(&bdev_lock); + return bdev; + } + spin_unlock(&bdev_lock); + + bdev = bdget(inode->i_rdev); + if (bdev) { + spin_lock(&bdev_lock); + if (!inode->i_bdev) { + /* + * We take an additional bd_inode->i_count for inode, + * and it's released in clear_inode() of inode. + * So, we can access it via ->i_mapping always + * without igrab(). + */ + atomic_inc(&bdev->bd_inode->i_count); + inode->i_bdev = bdev; + inode->i_mapping = bdev->bd_inode->i_mapping; + list_add(&inode->i_devices, &bdev->bd_inodes); + } + spin_unlock(&bdev_lock); + } + return bdev; +} + +/* Call when you free inode */ + +void bd_forget(struct inode *inode) +{ + struct block_device *bdev = NULL; + + spin_lock(&bdev_lock); + if (inode->i_bdev) { + if (!sb_is_blkdev_sb(inode->i_sb)) + bdev = inode->i_bdev; + __bd_forget(inode); + } + spin_unlock(&bdev_lock); + + if (bdev) + iput(bdev->bd_inode); +} + +int bd_claim(struct block_device *bdev, void *holder) +{ + int res; + spin_lock(&bdev_lock); + + /* first decide result */ + if (bdev->bd_holder == holder) + res = 0; /* already a holder */ + else if (bdev->bd_holder != NULL) + res = -EBUSY; /* held by someone else */ + else if (bdev->bd_contains == bdev) + res = 0; /* is a whole device which isn't held */ + + else if (bdev->bd_contains->bd_holder == bd_claim) + res = 0; /* is a partition of a device that is being partitioned */ + else if (bdev->bd_contains->bd_holder != NULL) + res = -EBUSY; /* is a partition of a held device */ + else + res = 0; /* is a partition of an un-held device */ + + /* now impose change */ + if (res==0) { + /* note that for a whole device bd_holders + * will be incremented twice, and bd_holder will + * be set to bd_claim before being set to holder + */ + bdev->bd_contains->bd_holders ++; + bdev->bd_contains->bd_holder = bd_claim; + bdev->bd_holders++; + bdev->bd_holder = holder; + } + spin_unlock(&bdev_lock); + return res; +} + +EXPORT_SYMBOL(bd_claim); + +void bd_release(struct block_device *bdev) +{ + spin_lock(&bdev_lock); + if (!--bdev->bd_contains->bd_holders) + bdev->bd_contains->bd_holder = NULL; + if (!--bdev->bd_holders) + bdev->bd_holder = NULL; + spin_unlock(&bdev_lock); +} + +EXPORT_SYMBOL(bd_release); + +#ifdef CONFIG_SYSFS +/* + * Functions for bd_claim_by_kobject / bd_release_from_kobject + * + * If a kobject is passed to bd_claim_by_kobject() + * and the kobject has a parent directory, + * following symlinks are created: + * o from the kobject to the claimed bdev + * o from "holders" directory of the bdev to the parent of the kobject + * bd_release_from_kobject() removes these symlinks. + * + * Example: + * If /dev/dm-0 maps to /dev/sda, kobject corresponding to + * /sys/block/dm-0/slaves is passed to bd_claim_by_kobject(), then: + * /sys/block/dm-0/slaves/sda --> /sys/block/sda + * /sys/block/sda/holders/dm-0 --> /sys/block/dm-0 + */ + +static int add_symlink(struct kobject *from, struct kobject *to) +{ + if (!from || !to) + return 0; + return sysfs_create_link(from, to, kobject_name(to)); +} + +static void del_symlink(struct kobject *from, struct kobject *to) +{ + if (!from || !to) + return; + sysfs_remove_link(from, kobject_name(to)); +} + +/* + * 'struct bd_holder' contains pointers to kobjects symlinked by + * bd_claim_by_kobject. + * It's connected to bd_holder_list which is protected by bdev->bd_sem. + */ +struct bd_holder { + struct list_head list; /* chain of holders of the bdev */ + int count; /* references from the holder */ + struct kobject *sdir; /* holder object, e.g. "/block/dm-0/slaves" */ + struct kobject *hdev; /* e.g. "/block/dm-0" */ + struct kobject *hdir; /* e.g. "/block/sda/holders" */ + struct kobject *sdev; /* e.g. "/block/sda" */ +}; + +/* + * Get references of related kobjects at once. + * Returns 1 on success. 0 on failure. + * + * Should call bd_holder_release_dirs() after successful use. + */ +static int bd_holder_grab_dirs(struct block_device *bdev, + struct bd_holder *bo) +{ + if (!bdev || !bo) + return 0; + + bo->sdir = kobject_get(bo->sdir); + if (!bo->sdir) + return 0; + + bo->hdev = kobject_get(bo->sdir->parent); + if (!bo->hdev) + goto fail_put_sdir; + + bo->sdev = kobject_get(&part_to_dev(bdev->bd_part)->kobj); + if (!bo->sdev) + goto fail_put_hdev; + + bo->hdir = kobject_get(bdev->bd_part->holder_dir); + if (!bo->hdir) + goto fail_put_sdev; + + return 1; + +fail_put_sdev: + kobject_put(bo->sdev); +fail_put_hdev: + kobject_put(bo->hdev); +fail_put_sdir: + kobject_put(bo->sdir); + + return 0; +} + +/* Put references of related kobjects at once. */ +static void bd_holder_release_dirs(struct bd_holder *bo) +{ + kobject_put(bo->hdir); + kobject_put(bo->sdev); + kobject_put(bo->hdev); + kobject_put(bo->sdir); +} + +static struct bd_holder *alloc_bd_holder(struct kobject *kobj) +{ + struct bd_holder *bo; + + bo = kzalloc(sizeof(*bo), GFP_KERNEL); + if (!bo) + return NULL; + + bo->count = 1; + bo->sdir = kobj; + + return bo; +} + +static void free_bd_holder(struct bd_holder *bo) +{ + kfree(bo); +} + +/** + * find_bd_holder - find matching struct bd_holder from the block device + * + * @bdev: struct block device to be searched + * @bo: target struct bd_holder + * + * Returns matching entry with @bo in @bdev->bd_holder_list. + * If found, increment the reference count and return the pointer. + * If not found, returns NULL. + */ +static struct bd_holder *find_bd_holder(struct block_device *bdev, + struct bd_holder *bo) +{ + struct bd_holder *tmp; + + list_for_each_entry(tmp, &bdev->bd_holder_list, list) + if (tmp->sdir == bo->sdir) { + tmp->count++; + return tmp; + } + + return NULL; +} + +/** + * add_bd_holder - create sysfs symlinks for bd_claim() relationship + * + * @bdev: block device to be bd_claimed + * @bo: preallocated and initialized by alloc_bd_holder() + * + * Add @bo to @bdev->bd_holder_list, create symlinks. + * + * Returns 0 if symlinks are created. + * Returns -ve if something fails. + */ +static int add_bd_holder(struct block_device *bdev, struct bd_holder *bo) +{ + int err; + + if (!bo) + return -EINVAL; + + if (!bd_holder_grab_dirs(bdev, bo)) + return -EBUSY; + + err = add_symlink(bo->sdir, bo->sdev); + if (err) + return err; + + err = add_symlink(bo->hdir, bo->hdev); + if (err) { + del_symlink(bo->sdir, bo->sdev); + return err; + } + + list_add_tail(&bo->list, &bdev->bd_holder_list); + return 0; +} + +/** + * del_bd_holder - delete sysfs symlinks for bd_claim() relationship + * + * @bdev: block device to be bd_claimed + * @kobj: holder's kobject + * + * If there is matching entry with @kobj in @bdev->bd_holder_list + * and no other bd_claim() from the same kobject, + * remove the struct bd_holder from the list, delete symlinks for it. + * + * Returns a pointer to the struct bd_holder when it's removed from the list + * and ready to be freed. + * Returns NULL if matching claim isn't found or there is other bd_claim() + * by the same kobject. + */ +static struct bd_holder *del_bd_holder(struct block_device *bdev, + struct kobject *kobj) +{ + struct bd_holder *bo; + + list_for_each_entry(bo, &bdev->bd_holder_list, list) { + if (bo->sdir == kobj) { + bo->count--; + BUG_ON(bo->count < 0); + if (!bo->count) { + list_del(&bo->list); + del_symlink(bo->sdir, bo->sdev); + del_symlink(bo->hdir, bo->hdev); + bd_holder_release_dirs(bo); + return bo; + } + break; + } + } + + return NULL; +} + +/** + * bd_claim_by_kobject - bd_claim() with additional kobject signature + * + * @bdev: block device to be claimed + * @holder: holder's signature + * @kobj: holder's kobject + * + * Do bd_claim() and if it succeeds, create sysfs symlinks between + * the bdev and the holder's kobject. + * Use bd_release_from_kobject() when relesing the claimed bdev. + * + * Returns 0 on success. (same as bd_claim()) + * Returns errno on failure. + */ +static int bd_claim_by_kobject(struct block_device *bdev, void *holder, + struct kobject *kobj) +{ + int err; + struct bd_holder *bo, *found; + + if (!kobj) + return -EINVAL; + + bo = alloc_bd_holder(kobj); + if (!bo) + return -ENOMEM; + + mutex_lock(&bdev->bd_mutex); + + err = bd_claim(bdev, holder); + if (err) + goto fail; + + found = find_bd_holder(bdev, bo); + if (found) + goto fail; + + err = add_bd_holder(bdev, bo); + if (err) + bd_release(bdev); + else + bo = NULL; +fail: + mutex_unlock(&bdev->bd_mutex); + free_bd_holder(bo); + return err; +} + +/** + * bd_release_from_kobject - bd_release() with additional kobject signature + * + * @bdev: block device to be released + * @kobj: holder's kobject + * + * Do bd_release() and remove sysfs symlinks created by bd_claim_by_kobject(). + */ +static void bd_release_from_kobject(struct block_device *bdev, + struct kobject *kobj) +{ + if (!kobj) + return; + + mutex_lock(&bdev->bd_mutex); + bd_release(bdev); + free_bd_holder(del_bd_holder(bdev, kobj)); + mutex_unlock(&bdev->bd_mutex); +} + +/** + * bd_claim_by_disk - wrapper function for bd_claim_by_kobject() + * + * @bdev: block device to be claimed + * @holder: holder's signature + * @disk: holder's gendisk + * + * Call bd_claim_by_kobject() with getting @disk->slave_dir. + */ +int bd_claim_by_disk(struct block_device *bdev, void *holder, + struct gendisk *disk) +{ + return bd_claim_by_kobject(bdev, holder, kobject_get(disk->slave_dir)); +} +EXPORT_SYMBOL_GPL(bd_claim_by_disk); + +/** + * bd_release_from_disk - wrapper function for bd_release_from_kobject() + * + * @bdev: block device to be claimed + * @disk: holder's gendisk + * + * Call bd_release_from_kobject() and put @disk->slave_dir. + */ +void bd_release_from_disk(struct block_device *bdev, struct gendisk *disk) +{ + bd_release_from_kobject(bdev, disk->slave_dir); + kobject_put(disk->slave_dir); +} +EXPORT_SYMBOL_GPL(bd_release_from_disk); +#endif + +/* + * Tries to open block device by device number. Use it ONLY if you + * really do not have anything better - i.e. when you are behind a + * truly sucky interface and all you are given is a device number. _Never_ + * to be used for internal purposes. If you ever need it - reconsider + * your API. + */ +struct block_device *open_by_devnum(dev_t dev, fmode_t mode) +{ + struct block_device *bdev = bdget(dev); + int err = -ENOMEM; + if (bdev) + err = blkdev_get(bdev, mode); + return err ? ERR_PTR(err) : bdev; +} + +EXPORT_SYMBOL(open_by_devnum); + +/** + * flush_disk - invalidates all buffer-cache entries on a disk + * + * @bdev: struct block device to be flushed + * + * Invalidates all buffer-cache entries on a disk. It should be called + * when a disk has been changed -- either by a media change or online + * resize. + */ +static void flush_disk(struct block_device *bdev) +{ + if (__invalidate_device(bdev)) { + char name[BDEVNAME_SIZE] = ""; + + if (bdev->bd_disk) + disk_name(bdev->bd_disk, 0, name); + printk(KERN_WARNING "VFS: busy inodes on changed media or " + "resized disk %s\n", name); + } + + if (!bdev->bd_disk) + return; + if (disk_partitionable(bdev->bd_disk)) + bdev->bd_invalidated = 1; +} + +/** + * check_disk_size_change - checks for disk size change and adjusts bdev size. + * @disk: struct gendisk to check + * @bdev: struct bdev to adjust. + * + * This routine checks to see if the bdev size does not match the disk size + * and adjusts it if it differs. + */ +void check_disk_size_change(struct gendisk *disk, struct block_device *bdev) +{ + loff_t disk_size, bdev_size; + + disk_size = (loff_t)get_capacity(disk) << 9; + bdev_size = i_size_read(bdev->bd_inode); + if (disk_size != bdev_size) { + char name[BDEVNAME_SIZE]; + + disk_name(disk, 0, name); + printk(KERN_INFO + "%s: detected capacity change from %lld to %lld\n", + name, bdev_size, disk_size); + i_size_write(bdev->bd_inode, disk_size); + flush_disk(bdev); + } +} +EXPORT_SYMBOL(check_disk_size_change); + +/** + * revalidate_disk - wrapper for lower-level driver's revalidate_disk call-back + * @disk: struct gendisk to be revalidated + * + * This routine is a wrapper for lower-level driver's revalidate_disk + * call-backs. It is used to do common pre and post operations needed + * for all revalidate_disk operations. + */ +int revalidate_disk(struct gendisk *disk) +{ + struct block_device *bdev; + int ret = 0; + + if (disk->fops->revalidate_disk) + ret = disk->fops->revalidate_disk(disk); + + bdev = bdget_disk(disk, 0); + if (!bdev) + return ret; + + mutex_lock(&bdev->bd_mutex); + check_disk_size_change(disk, bdev); + mutex_unlock(&bdev->bd_mutex); + bdput(bdev); + return ret; +} +EXPORT_SYMBOL(revalidate_disk); + +/* + * This routine checks whether a removable media has been changed, + * and invalidates all buffer-cache-entries in that case. This + * is a relatively slow routine, so we have to try to minimize using + * it. Thus it is called only upon a 'mount' or 'open'. This + * is the best way of combining speed and utility, I think. + * People changing diskettes in the middle of an operation deserve + * to lose :-) + */ +int check_disk_change(struct block_device *bdev) +{ + struct gendisk *disk = bdev->bd_disk; + struct block_device_operations * bdops = disk->fops; + + if (!bdops->media_changed) + return 0; + if (!bdops->media_changed(bdev->bd_disk)) + return 0; + + flush_disk(bdev); + if (bdops->revalidate_disk) + bdops->revalidate_disk(bdev->bd_disk); + return 1; +} + +EXPORT_SYMBOL(check_disk_change); + +void bd_set_size(struct block_device *bdev, loff_t size) +{ + unsigned bsize = bdev_hardsect_size(bdev); + + bdev->bd_inode->i_size = size; + while (bsize < PAGE_CACHE_SIZE) { + if (size & bsize) + break; + bsize <<= 1; + } + bdev->bd_block_size = bsize; + bdev->bd_inode->i_blkbits = blksize_bits(bsize); +} +EXPORT_SYMBOL(bd_set_size); + +static int __blkdev_put(struct block_device *bdev, fmode_t mode, int for_part); + +/* + * bd_mutex locking: + * + * mutex_lock(part->bd_mutex) + * mutex_lock_nested(whole->bd_mutex, 1) + */ + +static int __blkdev_get(struct block_device *bdev, fmode_t mode, int for_part) +{ + struct gendisk *disk; + int ret; + int partno; + int perm = 0; + + if (mode & FMODE_READ) + perm |= MAY_READ; + if (mode & FMODE_WRITE) + perm |= MAY_WRITE; + /* + * hooks: /n/, see "layering violations". + */ + ret = devcgroup_inode_permission(bdev->bd_inode, perm); + if (ret != 0) { + bdput(bdev); + return ret; + } + + lock_kernel(); + restart: + + ret = -ENXIO; + disk = get_gendisk(bdev->bd_dev, &partno); + if (!disk) + goto out_unlock_kernel; + + mutex_lock_nested(&bdev->bd_mutex, for_part); + if (!bdev->bd_openers) { + bdev->bd_disk = disk; + bdev->bd_contains = bdev; + if (!partno) { + struct backing_dev_info *bdi; + + ret = -ENXIO; + bdev->bd_part = disk_get_part(disk, partno); + if (!bdev->bd_part) + goto out_clear; + + if (disk->fops->open) { + ret = disk->fops->open(bdev, mode); + if (ret == -ERESTARTSYS) { + /* Lost a race with 'disk' being + * deleted, try again. + * See md.c + */ + disk_put_part(bdev->bd_part); + bdev->bd_part = NULL; + module_put(disk->fops->owner); + put_disk(disk); + bdev->bd_disk = NULL; + mutex_unlock(&bdev->bd_mutex); + goto restart; + } + if (ret) + goto out_clear; + } + if (!bdev->bd_openers) { + bd_set_size(bdev,(loff_t)get_capacity(disk)<<9); + bdi = blk_get_backing_dev_info(bdev); + if (bdi == NULL) + bdi = &default_backing_dev_info; + bdev->bd_inode->i_data.backing_dev_info = bdi; + } + if (bdev->bd_invalidated) + rescan_partitions(disk, bdev); + } else { + struct block_device *whole; + whole = bdget_disk(disk, 0); + ret = -ENOMEM; + if (!whole) + goto out_clear; + BUG_ON(for_part); + ret = __blkdev_get(whole, mode, 1); + if (ret) + goto out_clear; + bdev->bd_contains = whole; + bdev->bd_inode->i_data.backing_dev_info = + whole->bd_inode->i_data.backing_dev_info; + bdev->bd_part = disk_get_part(disk, partno); + if (!(disk->flags & GENHD_FL_UP) || + !bdev->bd_part || !bdev->bd_part->nr_sects) { + ret = -ENXIO; + goto out_clear; + } + bd_set_size(bdev, (loff_t)bdev->bd_part->nr_sects << 9); + } + } else { + put_disk(disk); + module_put(disk->fops->owner); + disk = NULL; + if (bdev->bd_contains == bdev) { + if (bdev->bd_disk->fops->open) { + ret = bdev->bd_disk->fops->open(bdev, mode); + if (ret) + goto out_unlock_bdev; + } + if (bdev->bd_invalidated) + rescan_partitions(bdev->bd_disk, bdev); + } + } + bdev->bd_openers++; + if (for_part) + bdev->bd_part_count++; + mutex_unlock(&bdev->bd_mutex); + unlock_kernel(); + return 0; + + out_clear: + disk_put_part(bdev->bd_part); + bdev->bd_disk = NULL; + bdev->bd_part = NULL; + bdev->bd_inode->i_data.backing_dev_info = &default_backing_dev_info; + if (bdev != bdev->bd_contains) + __blkdev_put(bdev->bd_contains, mode, 1); + bdev->bd_contains = NULL; + out_unlock_bdev: + mutex_unlock(&bdev->bd_mutex); + out_unlock_kernel: + unlock_kernel(); + + if (disk) + module_put(disk->fops->owner); + put_disk(disk); + bdput(bdev); + + return ret; +} + +int blkdev_get(struct block_device *bdev, fmode_t mode) +{ + return __blkdev_get(bdev, mode, 0); +} +EXPORT_SYMBOL(blkdev_get); + +static int blkdev_open(struct inode * inode, struct file * filp) +{ + struct block_device *bdev; + int res; + + /* + * Preserve backwards compatibility and allow large file access + * even if userspace doesn't ask for it explicitly. Some mkfs + * binary needs it. We might want to drop this workaround + * during an unstable branch. + */ + filp->f_flags |= O_LARGEFILE; + + if (filp->f_flags & O_NDELAY) + filp->f_mode |= FMODE_NDELAY; + if (filp->f_flags & O_EXCL) + filp->f_mode |= FMODE_EXCL; + if ((filp->f_flags & O_ACCMODE) == 3) + filp->f_mode |= FMODE_WRITE_IOCTL; + + bdev = bd_acquire(inode); + if (bdev == NULL) + return -ENOMEM; + + filp->f_mapping = bdev->bd_inode->i_mapping; + + res = blkdev_get(bdev, filp->f_mode); + if (res) + return res; + + if (filp->f_mode & FMODE_EXCL) { + res = bd_claim(bdev, filp); + if (res) + goto out_blkdev_put; + } + + return 0; + + out_blkdev_put: + blkdev_put(bdev, filp->f_mode); + return res; +} + +static int __blkdev_put(struct block_device *bdev, fmode_t mode, int for_part) +{ + int ret = 0; + struct gendisk *disk = bdev->bd_disk; + struct block_device *victim = NULL; + + mutex_lock_nested(&bdev->bd_mutex, for_part); + lock_kernel(); + if (for_part) + bdev->bd_part_count--; + + if (!--bdev->bd_openers) { + sync_blockdev(bdev); + kill_bdev(bdev); + } + if (bdev->bd_contains == bdev) { + if (disk->fops->release) + ret = disk->fops->release(disk, mode); + } + if (!bdev->bd_openers) { + struct module *owner = disk->fops->owner; + + put_disk(disk); + module_put(owner); + disk_put_part(bdev->bd_part); + bdev->bd_part = NULL; + bdev->bd_disk = NULL; + bdev->bd_inode->i_data.backing_dev_info = &default_backing_dev_info; + if (bdev != bdev->bd_contains) + victim = bdev->bd_contains; + bdev->bd_contains = NULL; + } + unlock_kernel(); + mutex_unlock(&bdev->bd_mutex); + bdput(bdev); + if (victim) + __blkdev_put(victim, mode, 1); + return ret; +} + +int blkdev_put(struct block_device *bdev, fmode_t mode) +{ + return __blkdev_put(bdev, mode, 0); +} +EXPORT_SYMBOL(blkdev_put); + +static int blkdev_close(struct inode * inode, struct file * filp) +{ + struct block_device *bdev = I_BDEV(filp->f_mapping->host); + if (bdev->bd_holder == filp) + bd_release(bdev); + return blkdev_put(bdev, filp->f_mode); +} + +static long block_ioctl(struct file *file, unsigned cmd, unsigned long arg) +{ + struct block_device *bdev = I_BDEV(file->f_mapping->host); + fmode_t mode = file->f_mode; + + /* + * O_NDELAY can be altered using fcntl(.., F_SETFL, ..), so we have + * to updated it before every ioctl. + */ + if (file->f_flags & O_NDELAY) + mode |= FMODE_NDELAY; + else + mode &= ~FMODE_NDELAY; + + return blkdev_ioctl(bdev, mode, cmd, arg); +} + +/* + * Try to release a page associated with block device when the system + * is under memory pressure. + */ +static int blkdev_releasepage(struct page *page, gfp_t wait) +{ + struct super_block *super = BDEV_I(page->mapping->host)->bdev.bd_super; + + if (super && super->s_op->bdev_try_to_free_page) + return super->s_op->bdev_try_to_free_page(super, page, wait); + + return try_to_free_buffers(page); +} + +static const struct address_space_operations def_blk_aops = { + .readpage = blkdev_readpage, + .writepage = blkdev_writepage, + .sync_page = block_sync_page, + .write_begin = blkdev_write_begin, + .write_end = blkdev_write_end, + .writepages = generic_writepages, + .releasepage = blkdev_releasepage, + .direct_IO = blkdev_direct_IO, +}; + +const struct file_operations def_blk_fops = { + .open = blkdev_open, + .release = blkdev_close, +#ifndef DDE_LINUX + .llseek = block_llseek, + .read = do_sync_read, + .write = do_sync_write, + .aio_read = generic_file_aio_read, + .aio_write = generic_file_aio_write_nolock, + .mmap = generic_file_mmap, + .fsync = block_fsync, + .unlocked_ioctl = block_ioctl, +#ifdef CONFIG_COMPAT + .compat_ioctl = compat_blkdev_ioctl, +#endif + .splice_read = generic_file_splice_read, + .splice_write = generic_file_splice_write, +#endif /* DDE_LINUX */ +}; + +int ioctl_by_bdev(struct block_device *bdev, unsigned cmd, unsigned long arg) +{ + int res; + mm_segment_t old_fs = get_fs(); + set_fs(KERNEL_DS); + res = blkdev_ioctl(bdev, 0, cmd, arg); + set_fs(old_fs); + return res; +} + +EXPORT_SYMBOL(ioctl_by_bdev); + +/** + * lookup_bdev - lookup a struct block_device by name + * @pathname: special file representing the block device + * + * Get a reference to the blockdevice at @pathname in the current + * namespace if possible and return it. Return ERR_PTR(error) + * otherwise. + */ +struct block_device *lookup_bdev(const char *pathname) +{ + struct block_device *bdev; + struct inode *inode; + struct path path; + int error; + + if (!pathname || !*pathname) + return ERR_PTR(-EINVAL); + + error = kern_path(pathname, LOOKUP_FOLLOW, &path); + if (error) + return ERR_PTR(error); + + inode = path.dentry->d_inode; + error = -ENOTBLK; + if (!S_ISBLK(inode->i_mode)) + goto fail; + error = -EACCES; + if (path.mnt->mnt_flags & MNT_NODEV) + goto fail; + error = -ENOMEM; + bdev = bd_acquire(inode); + if (!bdev) + goto fail; +out: + path_put(&path); + return bdev; +fail: + bdev = ERR_PTR(error); + goto out; +} +EXPORT_SYMBOL(lookup_bdev); + +/** + * open_bdev_exclusive - open a block device by name and set it up for use + * + * @path: special file representing the block device + * @mode: FMODE_... combination to pass be used + * @holder: owner for exclusion + * + * Open the blockdevice described by the special file at @path, claim it + * for the @holder. + */ +struct block_device *open_bdev_exclusive(const char *path, fmode_t mode, void *holder) +{ + struct block_device *bdev; + int error = 0; + + bdev = lookup_bdev(path); + if (IS_ERR(bdev)) + return bdev; + + error = blkdev_get(bdev, mode); + if (error) + return ERR_PTR(error); + error = -EACCES; + if ((mode & FMODE_WRITE) && bdev_read_only(bdev)) + goto blkdev_put; + error = bd_claim(bdev, holder); + if (error) + goto blkdev_put; + + return bdev; + +blkdev_put: + blkdev_put(bdev, mode); + return ERR_PTR(error); +} + +EXPORT_SYMBOL(open_bdev_exclusive); + +/** + * close_bdev_exclusive - close a blockdevice opened by open_bdev_exclusive() + * + * @bdev: blockdevice to close + * @mode: mode, must match that used to open. + * + * This is the counterpart to open_bdev_exclusive(). + */ +void close_bdev_exclusive(struct block_device *bdev, fmode_t mode) +{ + bd_release(bdev); + blkdev_put(bdev, mode); +} + +EXPORT_SYMBOL(close_bdev_exclusive); + +int __invalidate_device(struct block_device *bdev) +{ + struct super_block *sb = get_super(bdev); + int res = 0; + + if (sb) { + /* + * no need to lock the super, get_super holds the + * read mutex so the filesystem cannot go away + * under us (->put_super runs with the write lock + * hold). + */ + shrink_dcache_sb(sb); + res = invalidate_inodes(sb); + drop_super(sb); + } + invalidate_bdev(bdev); + return res; +} +EXPORT_SYMBOL(__invalidate_device); diff --git a/libdde_linux26/lib/src/fs/buffer.c b/libdde_linux26/lib/src/fs/buffer.c new file mode 100644 index 00000000..d3b1c445 --- /dev/null +++ b/libdde_linux26/lib/src/fs/buffer.c @@ -0,0 +1,3474 @@ +/* + * linux/fs/buffer.c + * + * Copyright (C) 1991, 1992, 2002 Linus Torvalds + */ + +/* + * Start bdflush() with kernel_thread not syscall - Paul Gortmaker, 12/95 + * + * Removed a lot of unnecessary code and simplified things now that + * the buffer cache isn't our primary cache - Andrew Tridgell 12/96 + * + * Speed up hash, lru, and free list operations. Use gfp() for allocating + * hash table, use SLAB cache for buffer heads. SMP threading. -DaveM + * + * Added 32k buffer block sizes - these are required older ARM systems. - RMK + * + * async buffer flushing, 1999 Andrea Arcangeli <andrea@suse.de> + */ + +#include <linux/kernel.h> +#include <linux/syscalls.h> +#include <linux/fs.h> +#include <linux/mm.h> +#include <linux/percpu.h> +#include <linux/slab.h> +#include <linux/capability.h> +#include <linux/blkdev.h> +#include <linux/file.h> +#include <linux/quotaops.h> +#include <linux/highmem.h> +#include <linux/module.h> +#include <linux/writeback.h> +#include <linux/hash.h> +#include <linux/suspend.h> +#include <linux/buffer_head.h> +#include <linux/task_io_accounting_ops.h> +#include <linux/bio.h> +#include <linux/notifier.h> +#include <linux/cpu.h> +#include <linux/bitops.h> +#include <linux/mpage.h> +#include <linux/bit_spinlock.h> + +static int fsync_buffers_list(spinlock_t *lock, struct list_head *list); + +#define BH_ENTRY(list) list_entry((list), struct buffer_head, b_assoc_buffers) + +inline void +init_buffer(struct buffer_head *bh, bh_end_io_t *handler, void *private) +{ + bh->b_end_io = handler; + bh->b_private = private; +} + +static int sync_buffer(void *word) +{ + struct block_device *bd; + struct buffer_head *bh + = container_of(word, struct buffer_head, b_state); + + smp_mb(); + bd = bh->b_bdev; + if (bd) + blk_run_address_space(bd->bd_inode->i_mapping); + io_schedule(); + return 0; +} + +void __lock_buffer(struct buffer_head *bh) +{ + wait_on_bit_lock(&bh->b_state, BH_Lock, sync_buffer, + TASK_UNINTERRUPTIBLE); +} +EXPORT_SYMBOL(__lock_buffer); + +void unlock_buffer(struct buffer_head *bh) +{ + clear_bit_unlock(BH_Lock, &bh->b_state); + smp_mb__after_clear_bit(); + wake_up_bit(&bh->b_state, BH_Lock); +} + +/* + * Block until a buffer comes unlocked. This doesn't stop it + * from becoming locked again - you have to lock it yourself + * if you want to preserve its state. + */ +void __wait_on_buffer(struct buffer_head * bh) +{ + wait_on_bit(&bh->b_state, BH_Lock, sync_buffer, TASK_UNINTERRUPTIBLE); +} + +static void +__clear_page_buffers(struct page *page) +{ + ClearPagePrivate(page); + set_page_private(page, 0); + page_cache_release(page); +} + + +static int quiet_error(struct buffer_head *bh) +{ + if (!test_bit(BH_Quiet, &bh->b_state) && printk_ratelimit()) + return 0; + return 1; +} + + +static void buffer_io_error(struct buffer_head *bh) +{ + char b[BDEVNAME_SIZE]; + printk(KERN_ERR "Buffer I/O error on device %s, logical block %Lu\n", + bdevname(bh->b_bdev, b), + (unsigned long long)bh->b_blocknr); +} + +/* + * End-of-IO handler helper function which does not touch the bh after + * unlocking it. + * Note: unlock_buffer() sort-of does touch the bh after unlocking it, but + * a race there is benign: unlock_buffer() only use the bh's address for + * hashing after unlocking the buffer, so it doesn't actually touch the bh + * itself. + */ +static void __end_buffer_read_notouch(struct buffer_head *bh, int uptodate) +{ + if (uptodate) { + set_buffer_uptodate(bh); + } else { + /* This happens, due to failed READA attempts. */ + clear_buffer_uptodate(bh); + } + unlock_buffer(bh); +} + +/* + * Default synchronous end-of-IO handler.. Just mark it up-to-date and + * unlock the buffer. This is what ll_rw_block uses too. + */ +void end_buffer_read_sync(struct buffer_head *bh, int uptodate) +{ + __end_buffer_read_notouch(bh, uptodate); + put_bh(bh); +} + +void end_buffer_write_sync(struct buffer_head *bh, int uptodate) +{ + char b[BDEVNAME_SIZE]; + + if (uptodate) { + set_buffer_uptodate(bh); + } else { + if (!buffer_eopnotsupp(bh) && !quiet_error(bh)) { + buffer_io_error(bh); + printk(KERN_WARNING "lost page write due to " + "I/O error on %s\n", + bdevname(bh->b_bdev, b)); + } + set_buffer_write_io_error(bh); + clear_buffer_uptodate(bh); + } + unlock_buffer(bh); + put_bh(bh); +} + +/* + * Write out and wait upon all the dirty data associated with a block + * device via its mapping. Does not take the superblock lock. + */ +int sync_blockdev(struct block_device *bdev) +{ +#ifndef DDE_LINUX + int ret = 0; + + if (bdev) + ret = filemap_write_and_wait(bdev->bd_inode->i_mapping); + return ret; +#else + WARN_UNIMPL; + return 0; +#endif /* DDE_LINUX */ +} +EXPORT_SYMBOL(sync_blockdev); + +/* + * Write out and wait upon all dirty data associated with this + * device. Filesystem data as well as the underlying block + * device. Takes the superblock lock. + */ +int fsync_bdev(struct block_device *bdev) +{ +#ifndef DDE_LINUX + struct super_block *sb = get_super(bdev); + if (sb) { + int res = fsync_super(sb); + drop_super(sb); + return res; + } + return sync_blockdev(bdev); +#else + WARN_UNIMPL; + return -1; +#endif +} + +/** + * freeze_bdev -- lock a filesystem and force it into a consistent state + * @bdev: blockdevice to lock + * + * This takes the block device bd_mount_sem to make sure no new mounts + * happen on bdev until thaw_bdev() is called. + * If a superblock is found on this device, we take the s_umount semaphore + * on it to make sure nobody unmounts until the snapshot creation is done. + * The reference counter (bd_fsfreeze_count) guarantees that only the last + * unfreeze process can unfreeze the frozen filesystem actually when multiple + * freeze requests arrive simultaneously. It counts up in freeze_bdev() and + * count down in thaw_bdev(). When it becomes 0, thaw_bdev() will unfreeze + * actually. + */ +struct super_block *freeze_bdev(struct block_device *bdev) +{ + struct super_block *sb; + int error = 0; + + mutex_lock(&bdev->bd_fsfreeze_mutex); + if (bdev->bd_fsfreeze_count > 0) { + bdev->bd_fsfreeze_count++; + sb = get_super(bdev); + mutex_unlock(&bdev->bd_fsfreeze_mutex); + return sb; + } + bdev->bd_fsfreeze_count++; + + down(&bdev->bd_mount_sem); + sb = get_super(bdev); + if (sb && !(sb->s_flags & MS_RDONLY)) { + sb->s_frozen = SB_FREEZE_WRITE; + smp_wmb(); + + __fsync_super(sb); + + sb->s_frozen = SB_FREEZE_TRANS; + smp_wmb(); + + sync_blockdev(sb->s_bdev); + + if (sb->s_op->freeze_fs) { + error = sb->s_op->freeze_fs(sb); + if (error) { + printk(KERN_ERR + "VFS:Filesystem freeze failed\n"); + sb->s_frozen = SB_UNFROZEN; + drop_super(sb); + up(&bdev->bd_mount_sem); + bdev->bd_fsfreeze_count--; + mutex_unlock(&bdev->bd_fsfreeze_mutex); + return ERR_PTR(error); + } + } + } + + sync_blockdev(bdev); + mutex_unlock(&bdev->bd_fsfreeze_mutex); + + return sb; /* thaw_bdev releases s->s_umount and bd_mount_sem */ +} +EXPORT_SYMBOL(freeze_bdev); + +/** + * thaw_bdev -- unlock filesystem + * @bdev: blockdevice to unlock + * @sb: associated superblock + * + * Unlocks the filesystem and marks it writeable again after freeze_bdev(). + */ +int thaw_bdev(struct block_device *bdev, struct super_block *sb) +{ + int error = 0; + + mutex_lock(&bdev->bd_fsfreeze_mutex); + if (!bdev->bd_fsfreeze_count) { + mutex_unlock(&bdev->bd_fsfreeze_mutex); + return -EINVAL; + } + + bdev->bd_fsfreeze_count--; + if (bdev->bd_fsfreeze_count > 0) { + if (sb) + drop_super(sb); + mutex_unlock(&bdev->bd_fsfreeze_mutex); + return 0; + } + + if (sb) { + BUG_ON(sb->s_bdev != bdev); + if (!(sb->s_flags & MS_RDONLY)) { + if (sb->s_op->unfreeze_fs) { + error = sb->s_op->unfreeze_fs(sb); + if (error) { + printk(KERN_ERR + "VFS:Filesystem thaw failed\n"); + sb->s_frozen = SB_FREEZE_TRANS; + bdev->bd_fsfreeze_count++; + mutex_unlock(&bdev->bd_fsfreeze_mutex); + return error; + } + } + sb->s_frozen = SB_UNFROZEN; + smp_wmb(); + wake_up(&sb->s_wait_unfrozen); + } + drop_super(sb); + } + + up(&bdev->bd_mount_sem); + mutex_unlock(&bdev->bd_fsfreeze_mutex); + return 0; +} +EXPORT_SYMBOL(thaw_bdev); + +/* + * Various filesystems appear to want __find_get_block to be non-blocking. + * But it's the page lock which protects the buffers. To get around this, + * we get exclusion from try_to_free_buffers with the blockdev mapping's + * private_lock. + * + * Hack idea: for the blockdev mapping, i_bufferlist_lock contention + * may be quite high. This code could TryLock the page, and if that + * succeeds, there is no need to take private_lock. (But if + * private_lock is contended then so is mapping->tree_lock). + */ +static struct buffer_head * +__find_get_block_slow(struct block_device *bdev, sector_t block) +{ + struct inode *bd_inode = bdev->bd_inode; + struct address_space *bd_mapping = bd_inode->i_mapping; + struct buffer_head *ret = NULL; + pgoff_t index; + struct buffer_head *bh; + struct buffer_head *head; + struct page *page; + int all_mapped = 1; + + index = block >> (PAGE_CACHE_SHIFT - bd_inode->i_blkbits); + page = find_get_page(bd_mapping, index); + if (!page) + goto out; + + spin_lock(&bd_mapping->private_lock); + if (!page_has_buffers(page)) + goto out_unlock; + head = page_buffers(page); + bh = head; + do { + if (bh->b_blocknr == block) { + ret = bh; + get_bh(bh); + goto out_unlock; + } + if (!buffer_mapped(bh)) + all_mapped = 0; + bh = bh->b_this_page; + } while (bh != head); + + /* we might be here because some of the buffers on this page are + * not mapped. This is due to various races between + * file io on the block device and getblk. It gets dealt with + * elsewhere, don't buffer_error if we had some unmapped buffers + */ + if (all_mapped) { + printk("__find_get_block_slow() failed. " + "block=%llu, b_blocknr=%llu\n", + (unsigned long long)block, + (unsigned long long)bh->b_blocknr); + printk("b_state=0x%08lx, b_size=%zu\n", + bh->b_state, bh->b_size); + printk("device blocksize: %d\n", 1 << bd_inode->i_blkbits); + } +out_unlock: + spin_unlock(&bd_mapping->private_lock); + page_cache_release(page); +out: + return ret; +} + +/* If invalidate_buffers() will trash dirty buffers, it means some kind + of fs corruption is going on. Trashing dirty data always imply losing + information that was supposed to be just stored on the physical layer + by the user. + + Thus invalidate_buffers in general usage is not allwowed to trash + dirty buffers. For example ioctl(FLSBLKBUF) expects dirty data to + be preserved. These buffers are simply skipped. + + We also skip buffers which are still in use. For example this can + happen if a userspace program is reading the block device. + + NOTE: In the case where the user removed a removable-media-disk even if + there's still dirty data not synced on disk (due a bug in the device driver + or due an error of the user), by not destroying the dirty buffers we could + generate corruption also on the next media inserted, thus a parameter is + necessary to handle this case in the most safe way possible (trying + to not corrupt also the new disk inserted with the data belonging to + the old now corrupted disk). Also for the ramdisk the natural thing + to do in order to release the ramdisk memory is to destroy dirty buffers. + + These are two special cases. Normal usage imply the device driver + to issue a sync on the device (without waiting I/O completion) and + then an invalidate_buffers call that doesn't trash dirty buffers. + + For handling cache coherency with the blkdev pagecache the 'update' case + is been introduced. It is needed to re-read from disk any pinned + buffer. NOTE: re-reading from disk is destructive so we can do it only + when we assume nobody is changing the buffercache under our I/O and when + we think the disk contains more recent information than the buffercache. + The update == 1 pass marks the buffers we need to update, the update == 2 + pass does the actual I/O. */ +void invalidate_bdev(struct block_device *bdev) +{ + struct address_space *mapping = bdev->bd_inode->i_mapping; + + if (mapping->nrpages == 0) + return; + +#ifndef DDE_LINUX + invalidate_bh_lrus(); + invalidate_mapping_pages(mapping, 0, -1); +#endif +} + +/* + * Kick pdflush then try to free up some ZONE_NORMAL memory. + */ +static void free_more_memory(void) +{ + struct zone *zone; + int nid; + +#ifndef DDE_LINUX + wakeup_pdflush(1024); + yield(); + + for_each_online_node(nid) { + (void)first_zones_zonelist(node_zonelist(nid, GFP_NOFS), + gfp_zone(GFP_NOFS), NULL, + &zone); + if (zone) + try_to_free_pages(node_zonelist(nid, GFP_NOFS), 0, + GFP_NOFS); + } +#else + WARN_UNIMPL; +#endif +} + +/* + * I/O completion handler for block_read_full_page() - pages + * which come unlocked at the end of I/O. + */ +static void end_buffer_async_read(struct buffer_head *bh, int uptodate) +{ + unsigned long flags; + struct buffer_head *first; + struct buffer_head *tmp; + struct page *page; + int page_uptodate = 1; + + BUG_ON(!buffer_async_read(bh)); + + page = bh->b_page; + if (uptodate) { + set_buffer_uptodate(bh); + } else { + clear_buffer_uptodate(bh); + if (!quiet_error(bh)) + buffer_io_error(bh); + SetPageError(page); + } + + /* + * Be _very_ careful from here on. Bad things can happen if + * two buffer heads end IO at almost the same time and both + * decide that the page is now completely done. + */ + first = page_buffers(page); + local_irq_save(flags); + bit_spin_lock(BH_Uptodate_Lock, &first->b_state); + clear_buffer_async_read(bh); + unlock_buffer(bh); + tmp = bh; + do { + if (!buffer_uptodate(tmp)) + page_uptodate = 0; + if (buffer_async_read(tmp)) { + BUG_ON(!buffer_locked(tmp)); + goto still_busy; + } + tmp = tmp->b_this_page; + } while (tmp != bh); + bit_spin_unlock(BH_Uptodate_Lock, &first->b_state); + local_irq_restore(flags); + + /* + * If none of the buffers had errors and they are all + * uptodate then we can set the page uptodate. + */ + if (page_uptodate && !PageError(page)) + SetPageUptodate(page); + unlock_page(page); + return; + +still_busy: + bit_spin_unlock(BH_Uptodate_Lock, &first->b_state); + local_irq_restore(flags); + return; +} + +/* + * Completion handler for block_write_full_page() - pages which are unlocked + * during I/O, and which have PageWriteback cleared upon I/O completion. + */ +static void end_buffer_async_write(struct buffer_head *bh, int uptodate) +{ + char b[BDEVNAME_SIZE]; + unsigned long flags; + struct buffer_head *first; + struct buffer_head *tmp; + struct page *page; + + BUG_ON(!buffer_async_write(bh)); + + page = bh->b_page; + if (uptodate) { + set_buffer_uptodate(bh); + } else { + if (!quiet_error(bh)) { + buffer_io_error(bh); + printk(KERN_WARNING "lost page write due to " + "I/O error on %s\n", + bdevname(bh->b_bdev, b)); + } + set_bit(AS_EIO, &page->mapping->flags); + set_buffer_write_io_error(bh); + clear_buffer_uptodate(bh); + SetPageError(page); + } + + first = page_buffers(page); + local_irq_save(flags); + bit_spin_lock(BH_Uptodate_Lock, &first->b_state); + + clear_buffer_async_write(bh); + unlock_buffer(bh); + tmp = bh->b_this_page; + while (tmp != bh) { + if (buffer_async_write(tmp)) { + BUG_ON(!buffer_locked(tmp)); + goto still_busy; + } + tmp = tmp->b_this_page; + } + bit_spin_unlock(BH_Uptodate_Lock, &first->b_state); + local_irq_restore(flags); + end_page_writeback(page); + return; + +still_busy: + bit_spin_unlock(BH_Uptodate_Lock, &first->b_state); + local_irq_restore(flags); + return; +} + +/* + * If a page's buffers are under async readin (end_buffer_async_read + * completion) then there is a possibility that another thread of + * control could lock one of the buffers after it has completed + * but while some of the other buffers have not completed. This + * locked buffer would confuse end_buffer_async_read() into not unlocking + * the page. So the absence of BH_Async_Read tells end_buffer_async_read() + * that this buffer is not under async I/O. + * + * The page comes unlocked when it has no locked buffer_async buffers + * left. + * + * PageLocked prevents anyone starting new async I/O reads any of + * the buffers. + * + * PageWriteback is used to prevent simultaneous writeout of the same + * page. + * + * PageLocked prevents anyone from starting writeback of a page which is + * under read I/O (PageWriteback is only ever set against a locked page). + */ +static void mark_buffer_async_read(struct buffer_head *bh) +{ + bh->b_end_io = end_buffer_async_read; + set_buffer_async_read(bh); +} + +void mark_buffer_async_write(struct buffer_head *bh) +{ + bh->b_end_io = end_buffer_async_write; + set_buffer_async_write(bh); +} +EXPORT_SYMBOL(mark_buffer_async_write); + + +/* + * fs/buffer.c contains helper functions for buffer-backed address space's + * fsync functions. A common requirement for buffer-based filesystems is + * that certain data from the backing blockdev needs to be written out for + * a successful fsync(). For example, ext2 indirect blocks need to be + * written back and waited upon before fsync() returns. + * + * The functions mark_buffer_inode_dirty(), fsync_inode_buffers(), + * inode_has_buffers() and invalidate_inode_buffers() are provided for the + * management of a list of dependent buffers at ->i_mapping->private_list. + * + * Locking is a little subtle: try_to_free_buffers() will remove buffers + * from their controlling inode's queue when they are being freed. But + * try_to_free_buffers() will be operating against the *blockdev* mapping + * at the time, not against the S_ISREG file which depends on those buffers. + * So the locking for private_list is via the private_lock in the address_space + * which backs the buffers. Which is different from the address_space + * against which the buffers are listed. So for a particular address_space, + * mapping->private_lock does *not* protect mapping->private_list! In fact, + * mapping->private_list will always be protected by the backing blockdev's + * ->private_lock. + * + * Which introduces a requirement: all buffers on an address_space's + * ->private_list must be from the same address_space: the blockdev's. + * + * address_spaces which do not place buffers at ->private_list via these + * utility functions are free to use private_lock and private_list for + * whatever they want. The only requirement is that list_empty(private_list) + * be true at clear_inode() time. + * + * FIXME: clear_inode should not call invalidate_inode_buffers(). The + * filesystems should do that. invalidate_inode_buffers() should just go + * BUG_ON(!list_empty). + * + * FIXME: mark_buffer_dirty_inode() is a data-plane operation. It should + * take an address_space, not an inode. And it should be called + * mark_buffer_dirty_fsync() to clearly define why those buffers are being + * queued up. + * + * FIXME: mark_buffer_dirty_inode() doesn't need to add the buffer to the + * list if it is already on a list. Because if the buffer is on a list, + * it *must* already be on the right one. If not, the filesystem is being + * silly. This will save a ton of locking. But first we have to ensure + * that buffers are taken *off* the old inode's list when they are freed + * (presumably in truncate). That requires careful auditing of all + * filesystems (do it inside bforget()). It could also be done by bringing + * b_inode back. + */ + +/* + * The buffer's backing address_space's private_lock must be held + */ +static void __remove_assoc_queue(struct buffer_head *bh) +{ + list_del_init(&bh->b_assoc_buffers); + WARN_ON(!bh->b_assoc_map); + if (buffer_write_io_error(bh)) + set_bit(AS_EIO, &bh->b_assoc_map->flags); + bh->b_assoc_map = NULL; +} + +int inode_has_buffers(struct inode *inode) +{ + return !list_empty(&inode->i_data.private_list); +} + +/* + * osync is designed to support O_SYNC io. It waits synchronously for + * all already-submitted IO to complete, but does not queue any new + * writes to the disk. + * + * To do O_SYNC writes, just queue the buffer writes with ll_rw_block as + * you dirty the buffers, and then use osync_inode_buffers to wait for + * completion. Any other dirty buffers which are not yet queued for + * write will not be flushed to disk by the osync. + */ +static int osync_buffers_list(spinlock_t *lock, struct list_head *list) +{ + struct buffer_head *bh; + struct list_head *p; + int err = 0; + + spin_lock(lock); +repeat: + list_for_each_prev(p, list) { + bh = BH_ENTRY(p); + if (buffer_locked(bh)) { + get_bh(bh); + spin_unlock(lock); + wait_on_buffer(bh); + if (!buffer_uptodate(bh)) + err = -EIO; + brelse(bh); + spin_lock(lock); + goto repeat; + } + } + spin_unlock(lock); + return err; +} + +/** + * sync_mapping_buffers - write out & wait upon a mapping's "associated" buffers + * @mapping: the mapping which wants those buffers written + * + * Starts I/O against the buffers at mapping->private_list, and waits upon + * that I/O. + * + * Basically, this is a convenience function for fsync(). + * @mapping is a file or directory which needs those buffers to be written for + * a successful fsync(). + */ +int sync_mapping_buffers(struct address_space *mapping) +{ + struct address_space *buffer_mapping = mapping->assoc_mapping; + + if (buffer_mapping == NULL || list_empty(&mapping->private_list)) + return 0; + + return fsync_buffers_list(&buffer_mapping->private_lock, + &mapping->private_list); +} +EXPORT_SYMBOL(sync_mapping_buffers); + +/* + * Called when we've recently written block `bblock', and it is known that + * `bblock' was for a buffer_boundary() buffer. This means that the block at + * `bblock + 1' is probably a dirty indirect block. Hunt it down and, if it's + * dirty, schedule it for IO. So that indirects merge nicely with their data. + */ +void write_boundary_block(struct block_device *bdev, + sector_t bblock, unsigned blocksize) +{ + struct buffer_head *bh = __find_get_block(bdev, bblock + 1, blocksize); + if (bh) { + if (buffer_dirty(bh)) + ll_rw_block(WRITE, 1, &bh); + put_bh(bh); + } +} + +void mark_buffer_dirty_inode(struct buffer_head *bh, struct inode *inode) +{ + struct address_space *mapping = inode->i_mapping; + struct address_space *buffer_mapping = bh->b_page->mapping; + + mark_buffer_dirty(bh); + if (!mapping->assoc_mapping) { + mapping->assoc_mapping = buffer_mapping; + } else { + BUG_ON(mapping->assoc_mapping != buffer_mapping); + } + if (!bh->b_assoc_map) { + spin_lock(&buffer_mapping->private_lock); + list_move_tail(&bh->b_assoc_buffers, + &mapping->private_list); + bh->b_assoc_map = mapping; + spin_unlock(&buffer_mapping->private_lock); + } +} +EXPORT_SYMBOL(mark_buffer_dirty_inode); + +/* + * Mark the page dirty, and set it dirty in the radix tree, and mark the inode + * dirty. + * + * If warn is true, then emit a warning if the page is not uptodate and has + * not been truncated. + */ +static void __set_page_dirty(struct page *page, + struct address_space *mapping, int warn) +{ + spin_lock_irq(&mapping->tree_lock); + if (page->mapping) { /* Race with truncate? */ + WARN_ON_ONCE(warn && !PageUptodate(page)); + + if (mapping_cap_account_dirty(mapping)) { + __inc_zone_page_state(page, NR_FILE_DIRTY); + __inc_bdi_stat(mapping->backing_dev_info, + BDI_RECLAIMABLE); + task_dirty_inc(current); + task_io_account_write(PAGE_CACHE_SIZE); + } + radix_tree_tag_set(&mapping->page_tree, + page_index(page), PAGECACHE_TAG_DIRTY); + } + spin_unlock_irq(&mapping->tree_lock); + __mark_inode_dirty(mapping->host, I_DIRTY_PAGES); +} + +/* + * Add a page to the dirty page list. + * + * It is a sad fact of life that this function is called from several places + * deeply under spinlocking. It may not sleep. + * + * If the page has buffers, the uptodate buffers are set dirty, to preserve + * dirty-state coherency between the page and the buffers. It the page does + * not have buffers then when they are later attached they will all be set + * dirty. + * + * The buffers are dirtied before the page is dirtied. There's a small race + * window in which a writepage caller may see the page cleanness but not the + * buffer dirtiness. That's fine. If this code were to set the page dirty + * before the buffers, a concurrent writepage caller could clear the page dirty + * bit, see a bunch of clean buffers and we'd end up with dirty buffers/clean + * page on the dirty page list. + * + * We use private_lock to lock against try_to_free_buffers while using the + * page's buffer list. Also use this to protect against clean buffers being + * added to the page after it was set dirty. + * + * FIXME: may need to call ->reservepage here as well. That's rather up to the + * address_space though. + */ +int __set_page_dirty_buffers(struct page *page) +{ + int newly_dirty; + struct address_space *mapping = page_mapping(page); + + if (unlikely(!mapping)) + return !TestSetPageDirty(page); + + spin_lock(&mapping->private_lock); + if (page_has_buffers(page)) { + struct buffer_head *head = page_buffers(page); + struct buffer_head *bh = head; + + do { + set_buffer_dirty(bh); + bh = bh->b_this_page; + } while (bh != head); + } + newly_dirty = !TestSetPageDirty(page); + spin_unlock(&mapping->private_lock); + + if (newly_dirty) + __set_page_dirty(page, mapping, 1); + return newly_dirty; +} +EXPORT_SYMBOL(__set_page_dirty_buffers); + +/* + * Write out and wait upon a list of buffers. + * + * We have conflicting pressures: we want to make sure that all + * initially dirty buffers get waited on, but that any subsequently + * dirtied buffers don't. After all, we don't want fsync to last + * forever if somebody is actively writing to the file. + * + * Do this in two main stages: first we copy dirty buffers to a + * temporary inode list, queueing the writes as we go. Then we clean + * up, waiting for those writes to complete. + * + * During this second stage, any subsequent updates to the file may end + * up refiling the buffer on the original inode's dirty list again, so + * there is a chance we will end up with a buffer queued for write but + * not yet completed on that list. So, as a final cleanup we go through + * the osync code to catch these locked, dirty buffers without requeuing + * any newly dirty buffers for write. + */ +static int fsync_buffers_list(spinlock_t *lock, struct list_head *list) +{ + struct buffer_head *bh; + struct list_head tmp; + struct address_space *mapping; + int err = 0, err2; + + INIT_LIST_HEAD(&tmp); + + spin_lock(lock); + while (!list_empty(list)) { + bh = BH_ENTRY(list->next); + mapping = bh->b_assoc_map; + __remove_assoc_queue(bh); + /* Avoid race with mark_buffer_dirty_inode() which does + * a lockless check and we rely on seeing the dirty bit */ + smp_mb(); + if (buffer_dirty(bh) || buffer_locked(bh)) { + list_add(&bh->b_assoc_buffers, &tmp); + bh->b_assoc_map = mapping; + if (buffer_dirty(bh)) { + get_bh(bh); + spin_unlock(lock); + /* + * Ensure any pending I/O completes so that + * ll_rw_block() actually writes the current + * contents - it is a noop if I/O is still in + * flight on potentially older contents. + */ + ll_rw_block(SWRITE_SYNC, 1, &bh); + brelse(bh); + spin_lock(lock); + } + } + } + + while (!list_empty(&tmp)) { + bh = BH_ENTRY(tmp.prev); + get_bh(bh); + mapping = bh->b_assoc_map; + __remove_assoc_queue(bh); + /* Avoid race with mark_buffer_dirty_inode() which does + * a lockless check and we rely on seeing the dirty bit */ + smp_mb(); + if (buffer_dirty(bh)) { + list_add(&bh->b_assoc_buffers, + &mapping->private_list); + bh->b_assoc_map = mapping; + } + spin_unlock(lock); + wait_on_buffer(bh); + if (!buffer_uptodate(bh)) + err = -EIO; + brelse(bh); + spin_lock(lock); + } + + spin_unlock(lock); + err2 = osync_buffers_list(lock, list); + if (err) + return err; + else + return err2; +} + +/* + * Invalidate any and all dirty buffers on a given inode. We are + * probably unmounting the fs, but that doesn't mean we have already + * done a sync(). Just drop the buffers from the inode list. + * + * NOTE: we take the inode's blockdev's mapping's private_lock. Which + * assumes that all the buffers are against the blockdev. Not true + * for reiserfs. + */ +void invalidate_inode_buffers(struct inode *inode) +{ + if (inode_has_buffers(inode)) { + struct address_space *mapping = &inode->i_data; + struct list_head *list = &mapping->private_list; + struct address_space *buffer_mapping = mapping->assoc_mapping; + + spin_lock(&buffer_mapping->private_lock); + while (!list_empty(list)) + __remove_assoc_queue(BH_ENTRY(list->next)); + spin_unlock(&buffer_mapping->private_lock); + } +} +EXPORT_SYMBOL(invalidate_inode_buffers); + +/* + * Remove any clean buffers from the inode's buffer list. This is called + * when we're trying to free the inode itself. Those buffers can pin it. + * + * Returns true if all buffers were removed. + */ +int remove_inode_buffers(struct inode *inode) +{ + int ret = 1; + + if (inode_has_buffers(inode)) { + struct address_space *mapping = &inode->i_data; + struct list_head *list = &mapping->private_list; + struct address_space *buffer_mapping = mapping->assoc_mapping; + + spin_lock(&buffer_mapping->private_lock); + while (!list_empty(list)) { + struct buffer_head *bh = BH_ENTRY(list->next); + if (buffer_dirty(bh)) { + ret = 0; + break; + } + __remove_assoc_queue(bh); + } + spin_unlock(&buffer_mapping->private_lock); + } + return ret; +} + +/* + * Create the appropriate buffers when given a page for data area and + * the size of each buffer.. Use the bh->b_this_page linked list to + * follow the buffers created. Return NULL if unable to create more + * buffers. + * + * The retry flag is used to differentiate async IO (paging, swapping) + * which may not fail from ordinary buffer allocations. + */ +struct buffer_head *alloc_page_buffers(struct page *page, unsigned long size, + int retry) +{ + struct buffer_head *bh, *head; + long offset; + +try_again: + head = NULL; + offset = PAGE_SIZE; + while ((offset -= size) >= 0) { + bh = alloc_buffer_head(GFP_NOFS); + if (!bh) + goto no_grow; + + bh->b_bdev = NULL; + bh->b_this_page = head; + bh->b_blocknr = -1; + head = bh; + + bh->b_state = 0; + atomic_set(&bh->b_count, 0); + bh->b_private = NULL; + bh->b_size = size; + + /* Link the buffer to its page */ + set_bh_page(bh, page, offset); + + init_buffer(bh, NULL, NULL); + } + return head; +/* + * In case anything failed, we just free everything we got. + */ +no_grow: + if (head) { + do { + bh = head; + head = head->b_this_page; + free_buffer_head(bh); + } while (head); + } + + /* + * Return failure for non-async IO requests. Async IO requests + * are not allowed to fail, so we have to wait until buffer heads + * become available. But we don't want tasks sleeping with + * partially complete buffers, so all were released above. + */ + if (!retry) + return NULL; + + /* We're _really_ low on memory. Now we just + * wait for old buffer heads to become free due to + * finishing IO. Since this is an async request and + * the reserve list is empty, we're sure there are + * async buffer heads in use. + */ + free_more_memory(); + goto try_again; +} +EXPORT_SYMBOL_GPL(alloc_page_buffers); + +static inline void +link_dev_buffers(struct page *page, struct buffer_head *head) +{ + struct buffer_head *bh, *tail; + + bh = head; + do { + tail = bh; + bh = bh->b_this_page; + } while (bh); + tail->b_this_page = head; + attach_page_buffers(page, head); +} + +/* + * Initialise the state of a blockdev page's buffers. + */ +static void +init_page_buffers(struct page *page, struct block_device *bdev, + sector_t block, int size) +{ + struct buffer_head *head = page_buffers(page); + struct buffer_head *bh = head; + int uptodate = PageUptodate(page); + + do { + if (!buffer_mapped(bh)) { + init_buffer(bh, NULL, NULL); + bh->b_bdev = bdev; + bh->b_blocknr = block; + if (uptodate) + set_buffer_uptodate(bh); + set_buffer_mapped(bh); + } + block++; + bh = bh->b_this_page; + } while (bh != head); +} + +/* + * Create the page-cache page that contains the requested block. + * + * This is user purely for blockdev mappings. + */ +static struct page * +grow_dev_page(struct block_device *bdev, sector_t block, + pgoff_t index, int size) +{ + struct inode *inode = bdev->bd_inode; + struct page *page; + struct buffer_head *bh; + +#ifdef DDE_LINUX + WARN_UNIMPL; + return NULL; +#endif + + page = find_or_create_page(inode->i_mapping, index, + (mapping_gfp_mask(inode->i_mapping) & ~__GFP_FS)|__GFP_MOVABLE); + if (!page) + return NULL; + + BUG_ON(!PageLocked(page)); + + if (page_has_buffers(page)) { + bh = page_buffers(page); + if (bh->b_size == size) { + init_page_buffers(page, bdev, block, size); + return page; + } + if (!try_to_free_buffers(page)) + goto failed; + } + + /* + * Allocate some buffers for this page + */ + bh = alloc_page_buffers(page, size, 0); + if (!bh) + goto failed; + + /* + * Link the page to the buffers and initialise them. Take the + * lock to be atomic wrt __find_get_block(), which does not + * run under the page lock. + */ + spin_lock(&inode->i_mapping->private_lock); + link_dev_buffers(page, bh); + init_page_buffers(page, bdev, block, size); + spin_unlock(&inode->i_mapping->private_lock); + return page; + +failed: + BUG(); + unlock_page(page); + page_cache_release(page); + return NULL; +} + +/* + * Create buffers for the specified block device block's page. If + * that page was dirty, the buffers are set dirty also. + */ +static int +grow_buffers(struct block_device *bdev, sector_t block, int size) +{ + struct page *page; + pgoff_t index; + int sizebits; + + sizebits = -1; + do { + sizebits++; + } while ((size << sizebits) < PAGE_SIZE); + + index = block >> sizebits; + + /* + * Check for a block which wants to lie outside our maximum possible + * pagecache index. (this comparison is done using sector_t types). + */ + if (unlikely(index != block >> sizebits)) { + char b[BDEVNAME_SIZE]; + + printk(KERN_ERR "%s: requested out-of-range block %llu for " + "device %s\n", + __func__, (unsigned long long)block, + bdevname(bdev, b)); + return -EIO; + } + block = index << sizebits; + /* Create a page with the proper size buffers.. */ + page = grow_dev_page(bdev, block, index, size); + if (!page) + return 0; + unlock_page(page); + page_cache_release(page); + return 1; +} + +static struct buffer_head * +__getblk_slow(struct block_device *bdev, sector_t block, int size) +{ + /* Size must be multiple of hard sectorsize */ + if (unlikely(size & (bdev_hardsect_size(bdev)-1) || + (size < 512 || size > PAGE_SIZE))) { + printk(KERN_ERR "getblk(): invalid block size %d requested\n", + size); + printk(KERN_ERR "hardsect size: %d\n", + bdev_hardsect_size(bdev)); + + dump_stack(); + return NULL; + } + + for (;;) { + struct buffer_head * bh; + int ret; + + bh = __find_get_block(bdev, block, size); + if (bh) + return bh; + + ret = grow_buffers(bdev, block, size); + if (ret < 0) + return NULL; + if (ret == 0) + free_more_memory(); + } +} + +/* + * The relationship between dirty buffers and dirty pages: + * + * Whenever a page has any dirty buffers, the page's dirty bit is set, and + * the page is tagged dirty in its radix tree. + * + * At all times, the dirtiness of the buffers represents the dirtiness of + * subsections of the page. If the page has buffers, the page dirty bit is + * merely a hint about the true dirty state. + * + * When a page is set dirty in its entirety, all its buffers are marked dirty + * (if the page has buffers). + * + * When a buffer is marked dirty, its page is dirtied, but the page's other + * buffers are not. + * + * Also. When blockdev buffers are explicitly read with bread(), they + * individually become uptodate. But their backing page remains not + * uptodate - even if all of its buffers are uptodate. A subsequent + * block_read_full_page() against that page will discover all the uptodate + * buffers, will set the page uptodate and will perform no I/O. + */ + +/** + * mark_buffer_dirty - mark a buffer_head as needing writeout + * @bh: the buffer_head to mark dirty + * + * mark_buffer_dirty() will set the dirty bit against the buffer, then set its + * backing page dirty, then tag the page as dirty in its address_space's radix + * tree and then attach the address_space's inode to its superblock's dirty + * inode list. + * + * mark_buffer_dirty() is atomic. It takes bh->b_page->mapping->private_lock, + * mapping->tree_lock and the global inode_lock. + */ +void mark_buffer_dirty(struct buffer_head *bh) +{ +#ifndef DDE_LINUX + WARN_ON_ONCE(!buffer_uptodate(bh)); + + /* + * Very *carefully* optimize the it-is-already-dirty case. + * + * Don't let the final "is it dirty" escape to before we + * perhaps modified the buffer. + */ + if (buffer_dirty(bh)) { + smp_mb(); + if (buffer_dirty(bh)) + return; + } + + if (!test_set_buffer_dirty(bh)) { + struct page *page = bh->b_page; + if (!TestSetPageDirty(page)) + __set_page_dirty(page, page_mapping(page), 0); + } +#else + WARN_UNIMPL; +#endif +} + +/* + * Decrement a buffer_head's reference count. If all buffers against a page + * have zero reference count, are clean and unlocked, and if the page is clean + * and unlocked then try_to_free_buffers() may strip the buffers from the page + * in preparation for freeing it (sometimes, rarely, buffers are removed from + * a page but it ends up not being freed, and buffers may later be reattached). + */ +void __brelse(struct buffer_head * buf) +{ + if (atomic_read(&buf->b_count)) { + put_bh(buf); + return; + } + WARN(1, KERN_ERR "VFS: brelse: Trying to free free buffer\n"); +} + +/* + * bforget() is like brelse(), except it discards any + * potentially dirty data. + */ +void __bforget(struct buffer_head *bh) +{ + clear_buffer_dirty(bh); + if (bh->b_assoc_map) { + struct address_space *buffer_mapping = bh->b_page->mapping; + + spin_lock(&buffer_mapping->private_lock); + list_del_init(&bh->b_assoc_buffers); + bh->b_assoc_map = NULL; + spin_unlock(&buffer_mapping->private_lock); + } + __brelse(bh); +} + +static struct buffer_head *__bread_slow(struct buffer_head *bh) +{ + lock_buffer(bh); + if (buffer_uptodate(bh)) { + unlock_buffer(bh); + return bh; + } else { + get_bh(bh); + bh->b_end_io = end_buffer_read_sync; + submit_bh(READ, bh); + wait_on_buffer(bh); + if (buffer_uptodate(bh)) + return bh; + } + brelse(bh); + return NULL; +} + +/* + * Per-cpu buffer LRU implementation. To reduce the cost of __find_get_block(). + * The bhs[] array is sorted - newest buffer is at bhs[0]. Buffers have their + * refcount elevated by one when they're in an LRU. A buffer can only appear + * once in a particular CPU's LRU. A single buffer can be present in multiple + * CPU's LRUs at the same time. + * + * This is a transparent caching front-end to sb_bread(), sb_getblk() and + * sb_find_get_block(). + * + * The LRUs themselves only need locking against invalidate_bh_lrus. We use + * a local interrupt disable for that. + */ + +#define BH_LRU_SIZE 8 + +struct bh_lru { + struct buffer_head *bhs[BH_LRU_SIZE]; +}; + +static DEFINE_PER_CPU(struct bh_lru, bh_lrus) = {{ NULL }}; + +#ifdef CONFIG_SMP +#define bh_lru_lock() local_irq_disable() +#define bh_lru_unlock() local_irq_enable() +#else +#define bh_lru_lock() preempt_disable() +#define bh_lru_unlock() preempt_enable() +#endif + +static inline void check_irqs_on(void) +{ +#ifdef irqs_disabled + BUG_ON(irqs_disabled()); +#endif +} + +/* + * The LRU management algorithm is dopey-but-simple. Sorry. + */ +static void bh_lru_install(struct buffer_head *bh) +{ + struct buffer_head *evictee = NULL; + struct bh_lru *lru; + + check_irqs_on(); + bh_lru_lock(); + lru = &__get_cpu_var(bh_lrus); + if (lru->bhs[0] != bh) { + struct buffer_head *bhs[BH_LRU_SIZE]; + int in; + int out = 0; + + get_bh(bh); + bhs[out++] = bh; + for (in = 0; in < BH_LRU_SIZE; in++) { + struct buffer_head *bh2 = lru->bhs[in]; + + if (bh2 == bh) { + __brelse(bh2); + } else { + if (out >= BH_LRU_SIZE) { + BUG_ON(evictee != NULL); + evictee = bh2; + } else { + bhs[out++] = bh2; + } + } + } + while (out < BH_LRU_SIZE) + bhs[out++] = NULL; + memcpy(lru->bhs, bhs, sizeof(bhs)); + } + bh_lru_unlock(); + + if (evictee) + __brelse(evictee); +} + +/* + * Look up the bh in this cpu's LRU. If it's there, move it to the head. + */ +static struct buffer_head * +lookup_bh_lru(struct block_device *bdev, sector_t block, unsigned size) +{ + struct buffer_head *ret = NULL; + struct bh_lru *lru; + unsigned int i; + + check_irqs_on(); + bh_lru_lock(); + lru = &__get_cpu_var(bh_lrus); + for (i = 0; i < BH_LRU_SIZE; i++) { + struct buffer_head *bh = lru->bhs[i]; + + if (bh && bh->b_bdev == bdev && + bh->b_blocknr == block && bh->b_size == size) { + if (i) { + while (i) { + lru->bhs[i] = lru->bhs[i - 1]; + i--; + } + lru->bhs[0] = bh; + } + get_bh(bh); + ret = bh; + break; + } + } + bh_lru_unlock(); + return ret; +} + +/* + * Perform a pagecache lookup for the matching buffer. If it's there, refresh + * it in the LRU and mark it as accessed. If it is not present then return + * NULL + */ +struct buffer_head * +__find_get_block(struct block_device *bdev, sector_t block, unsigned size) +{ + struct buffer_head *bh = lookup_bh_lru(bdev, block, size); + + if (bh == NULL) { + bh = __find_get_block_slow(bdev, block); + if (bh) + bh_lru_install(bh); + } + if (bh) + touch_buffer(bh); + return bh; +} +EXPORT_SYMBOL(__find_get_block); + +/* + * __getblk will locate (and, if necessary, create) the buffer_head + * which corresponds to the passed block_device, block and size. The + * returned buffer has its reference count incremented. + * + * __getblk() cannot fail - it just keeps trying. If you pass it an + * illegal block number, __getblk() will happily return a buffer_head + * which represents the non-existent block. Very weird. + * + * __getblk() will lock up the machine if grow_dev_page's try_to_free_buffers() + * attempt is failing. FIXME, perhaps? + */ +struct buffer_head * +__getblk(struct block_device *bdev, sector_t block, unsigned size) +{ + struct buffer_head *bh = __find_get_block(bdev, block, size); + + might_sleep(); + if (bh == NULL) + bh = __getblk_slow(bdev, block, size); + return bh; +} +EXPORT_SYMBOL(__getblk); + +/* + * Do async read-ahead on a buffer.. + */ +void __breadahead(struct block_device *bdev, sector_t block, unsigned size) +{ + struct buffer_head *bh = __getblk(bdev, block, size); + if (likely(bh)) { + ll_rw_block(READA, 1, &bh); + brelse(bh); + } +} +EXPORT_SYMBOL(__breadahead); + +/** + * __bread() - reads a specified block and returns the bh + * @bdev: the block_device to read from + * @block: number of block + * @size: size (in bytes) to read + * + * Reads a specified block, and returns buffer head that contains it. + * It returns NULL if the block was unreadable. + */ +struct buffer_head * +__bread(struct block_device *bdev, sector_t block, unsigned size) +{ + struct buffer_head *bh = __getblk(bdev, block, size); + + if (likely(bh) && !buffer_uptodate(bh)) + bh = __bread_slow(bh); + return bh; +} +EXPORT_SYMBOL(__bread); + +/* + * invalidate_bh_lrus() is called rarely - but not only at unmount. + * This doesn't race because it runs in each cpu either in irq + * or with preempt disabled. + */ +static void invalidate_bh_lru(void *arg) +{ + struct bh_lru *b = &get_cpu_var(bh_lrus); + int i; + + for (i = 0; i < BH_LRU_SIZE; i++) { + brelse(b->bhs[i]); + b->bhs[i] = NULL; + } + put_cpu_var(bh_lrus); +} + +void invalidate_bh_lrus(void) +{ +#ifndef DDE_LINUX + on_each_cpu(invalidate_bh_lru, NULL, 1); +#endif +} +EXPORT_SYMBOL_GPL(invalidate_bh_lrus); + +void set_bh_page(struct buffer_head *bh, + struct page *page, unsigned long offset) +{ + bh->b_page = page; + BUG_ON(offset >= PAGE_SIZE); + if (PageHighMem(page)) + /* + * This catches illegal uses and preserves the offset: + */ + bh->b_data = (char *)(0 + offset); + else + bh->b_data = page_address(page) + offset; +} +EXPORT_SYMBOL(set_bh_page); + +/* + * Called when truncating a buffer on a page completely. + */ +static void discard_buffer(struct buffer_head * bh) +{ + lock_buffer(bh); + clear_buffer_dirty(bh); + bh->b_bdev = NULL; + clear_buffer_mapped(bh); + clear_buffer_req(bh); + clear_buffer_new(bh); + clear_buffer_delay(bh); + clear_buffer_unwritten(bh); + unlock_buffer(bh); +} + +/** + * block_invalidatepage - invalidate part of all of a buffer-backed page + * + * @page: the page which is affected + * @offset: the index of the truncation point + * + * block_invalidatepage() is called when all or part of the page has become + * invalidatedby a truncate operation. + * + * block_invalidatepage() does not have to release all buffers, but it must + * ensure that no dirty buffer is left outside @offset and that no I/O + * is underway against any of the blocks which are outside the truncation + * point. Because the caller is about to free (and possibly reuse) those + * blocks on-disk. + */ +void block_invalidatepage(struct page *page, unsigned long offset) +{ + struct buffer_head *head, *bh, *next; + unsigned int curr_off = 0; + + BUG_ON(!PageLocked(page)); + if (!page_has_buffers(page)) + goto out; + + head = page_buffers(page); + bh = head; + do { + unsigned int next_off = curr_off + bh->b_size; + next = bh->b_this_page; + + /* + * is this block fully invalidated? + */ + if (offset <= curr_off) + discard_buffer(bh); + curr_off = next_off; + bh = next; + } while (bh != head); + + /* + * We release buffers only if the entire page is being invalidated. + * The get_block cached value has been unconditionally invalidated, + * so real IO is not possible anymore. + */ + if (offset == 0) + try_to_release_page(page, 0); +out: + return; +} +EXPORT_SYMBOL(block_invalidatepage); + +/* + * We attach and possibly dirty the buffers atomically wrt + * __set_page_dirty_buffers() via private_lock. try_to_free_buffers + * is already excluded via the page lock. + */ +void create_empty_buffers(struct page *page, + unsigned long blocksize, unsigned long b_state) +{ + struct buffer_head *bh, *head, *tail; + + head = alloc_page_buffers(page, blocksize, 1); + bh = head; + do { + bh->b_state |= b_state; + tail = bh; + bh = bh->b_this_page; + } while (bh); + tail->b_this_page = head; + + spin_lock(&page->mapping->private_lock); + if (PageUptodate(page) || PageDirty(page)) { + bh = head; + do { + if (PageDirty(page)) + set_buffer_dirty(bh); + if (PageUptodate(page)) + set_buffer_uptodate(bh); + bh = bh->b_this_page; + } while (bh != head); + } + attach_page_buffers(page, head); + spin_unlock(&page->mapping->private_lock); +} +EXPORT_SYMBOL(create_empty_buffers); + +/* + * We are taking a block for data and we don't want any output from any + * buffer-cache aliases starting from return from that function and + * until the moment when something will explicitly mark the buffer + * dirty (hopefully that will not happen until we will free that block ;-) + * We don't even need to mark it not-uptodate - nobody can expect + * anything from a newly allocated buffer anyway. We used to used + * unmap_buffer() for such invalidation, but that was wrong. We definitely + * don't want to mark the alias unmapped, for example - it would confuse + * anyone who might pick it with bread() afterwards... + * + * Also.. Note that bforget() doesn't lock the buffer. So there can + * be writeout I/O going on against recently-freed buffers. We don't + * wait on that I/O in bforget() - it's more efficient to wait on the I/O + * only if we really need to. That happens here. + */ +void unmap_underlying_metadata(struct block_device *bdev, sector_t block) +{ + struct buffer_head *old_bh; + + might_sleep(); + + old_bh = __find_get_block_slow(bdev, block); + if (old_bh) { + clear_buffer_dirty(old_bh); + wait_on_buffer(old_bh); + clear_buffer_req(old_bh); + __brelse(old_bh); + } +} +EXPORT_SYMBOL(unmap_underlying_metadata); + +/* + * NOTE! All mapped/uptodate combinations are valid: + * + * Mapped Uptodate Meaning + * + * No No "unknown" - must do get_block() + * No Yes "hole" - zero-filled + * Yes No "allocated" - allocated on disk, not read in + * Yes Yes "valid" - allocated and up-to-date in memory. + * + * "Dirty" is valid only with the last case (mapped+uptodate). + */ + +/* + * While block_write_full_page is writing back the dirty buffers under + * the page lock, whoever dirtied the buffers may decide to clean them + * again at any time. We handle that by only looking at the buffer + * state inside lock_buffer(). + * + * If block_write_full_page() is called for regular writeback + * (wbc->sync_mode == WB_SYNC_NONE) then it will redirty a page which has a + * locked buffer. This only can happen if someone has written the buffer + * directly, with submit_bh(). At the address_space level PageWriteback + * prevents this contention from occurring. + */ +static int __block_write_full_page(struct inode *inode, struct page *page, + get_block_t *get_block, struct writeback_control *wbc) +{ + int err; + sector_t block; + sector_t last_block; + struct buffer_head *bh, *head; + const unsigned blocksize = 1 << inode->i_blkbits; + int nr_underway = 0; + + BUG_ON(!PageLocked(page)); + + last_block = (i_size_read(inode) - 1) >> inode->i_blkbits; + + if (!page_has_buffers(page)) { + create_empty_buffers(page, blocksize, + (1 << BH_Dirty)|(1 << BH_Uptodate)); + } + + /* + * Be very careful. We have no exclusion from __set_page_dirty_buffers + * here, and the (potentially unmapped) buffers may become dirty at + * any time. If a buffer becomes dirty here after we've inspected it + * then we just miss that fact, and the page stays dirty. + * + * Buffers outside i_size may be dirtied by __set_page_dirty_buffers; + * handle that here by just cleaning them. + */ + + block = (sector_t)page->index << (PAGE_CACHE_SHIFT - inode->i_blkbits); + head = page_buffers(page); + bh = head; + + /* + * Get all the dirty buffers mapped to disk addresses and + * handle any aliases from the underlying blockdev's mapping. + */ + do { + if (block > last_block) { + /* + * mapped buffers outside i_size will occur, because + * this page can be outside i_size when there is a + * truncate in progress. + */ + /* + * The buffer was zeroed by block_write_full_page() + */ + clear_buffer_dirty(bh); + set_buffer_uptodate(bh); + } else if ((!buffer_mapped(bh) || buffer_delay(bh)) && + buffer_dirty(bh)) { + WARN_ON(bh->b_size != blocksize); + err = get_block(inode, block, bh, 1); + if (err) + goto recover; + clear_buffer_delay(bh); + if (buffer_new(bh)) { + /* blockdev mappings never come here */ + clear_buffer_new(bh); + unmap_underlying_metadata(bh->b_bdev, + bh->b_blocknr); + } + } + bh = bh->b_this_page; + block++; + } while (bh != head); + + do { + if (!buffer_mapped(bh)) + continue; + /* + * If it's a fully non-blocking write attempt and we cannot + * lock the buffer then redirty the page. Note that this can + * potentially cause a busy-wait loop from pdflush and kswapd + * activity, but those code paths have their own higher-level + * throttling. + */ + if (wbc->sync_mode != WB_SYNC_NONE || !wbc->nonblocking) { + lock_buffer(bh); + } else if (!trylock_buffer(bh)) { + redirty_page_for_writepage(wbc, page); + continue; + } + if (test_clear_buffer_dirty(bh)) { + mark_buffer_async_write(bh); + } else { + unlock_buffer(bh); + } + } while ((bh = bh->b_this_page) != head); + + /* + * The page and its buffers are protected by PageWriteback(), so we can + * drop the bh refcounts early. + */ + BUG_ON(PageWriteback(page)); + set_page_writeback(page); + + do { + struct buffer_head *next = bh->b_this_page; + if (buffer_async_write(bh)) { + submit_bh(WRITE, bh); + nr_underway++; + } + bh = next; + } while (bh != head); + unlock_page(page); + + err = 0; +done: + if (nr_underway == 0) { + /* + * The page was marked dirty, but the buffers were + * clean. Someone wrote them back by hand with + * ll_rw_block/submit_bh. A rare case. + */ + end_page_writeback(page); + + /* + * The page and buffer_heads can be released at any time from + * here on. + */ + } + return err; + +recover: + /* + * ENOSPC, or some other error. We may already have added some + * blocks to the file, so we need to write these out to avoid + * exposing stale data. + * The page is currently locked and not marked for writeback + */ + bh = head; + /* Recovery: lock and submit the mapped buffers */ + do { + if (buffer_mapped(bh) && buffer_dirty(bh) && + !buffer_delay(bh)) { + lock_buffer(bh); + mark_buffer_async_write(bh); + } else { + /* + * The buffer may have been set dirty during + * attachment to a dirty page. + */ + clear_buffer_dirty(bh); + } + } while ((bh = bh->b_this_page) != head); + SetPageError(page); + BUG_ON(PageWriteback(page)); + mapping_set_error(page->mapping, err); + set_page_writeback(page); + do { + struct buffer_head *next = bh->b_this_page; + if (buffer_async_write(bh)) { + clear_buffer_dirty(bh); + submit_bh(WRITE, bh); + nr_underway++; + } + bh = next; + } while (bh != head); + unlock_page(page); + goto done; +} + +/* + * If a page has any new buffers, zero them out here, and mark them uptodate + * and dirty so they'll be written out (in order to prevent uninitialised + * block data from leaking). And clear the new bit. + */ +void page_zero_new_buffers(struct page *page, unsigned from, unsigned to) +{ + unsigned int block_start, block_end; + struct buffer_head *head, *bh; + + BUG_ON(!PageLocked(page)); + if (!page_has_buffers(page)) + return; + + bh = head = page_buffers(page); + block_start = 0; + do { + block_end = block_start + bh->b_size; + + if (buffer_new(bh)) { + if (block_end > from && block_start < to) { + if (!PageUptodate(page)) { + unsigned start, size; + + start = max(from, block_start); + size = min(to, block_end) - start; + + zero_user(page, start, size); + set_buffer_uptodate(bh); + } + + clear_buffer_new(bh); + mark_buffer_dirty(bh); + } + } + + block_start = block_end; + bh = bh->b_this_page; + } while (bh != head); +} +EXPORT_SYMBOL(page_zero_new_buffers); + +static int __block_prepare_write(struct inode *inode, struct page *page, + unsigned from, unsigned to, get_block_t *get_block) +{ + unsigned block_start, block_end; + sector_t block; + int err = 0; + unsigned blocksize, bbits; + struct buffer_head *bh, *head, *wait[2], **wait_bh=wait; + + BUG_ON(!PageLocked(page)); + BUG_ON(from > PAGE_CACHE_SIZE); + BUG_ON(to > PAGE_CACHE_SIZE); + BUG_ON(from > to); + + blocksize = 1 << inode->i_blkbits; + if (!page_has_buffers(page)) + create_empty_buffers(page, blocksize, 0); + head = page_buffers(page); + + bbits = inode->i_blkbits; + block = (sector_t)page->index << (PAGE_CACHE_SHIFT - bbits); + + for(bh = head, block_start = 0; bh != head || !block_start; + block++, block_start=block_end, bh = bh->b_this_page) { + block_end = block_start + blocksize; + if (block_end <= from || block_start >= to) { + if (PageUptodate(page)) { + if (!buffer_uptodate(bh)) + set_buffer_uptodate(bh); + } + continue; + } + if (buffer_new(bh)) + clear_buffer_new(bh); + if (!buffer_mapped(bh)) { + WARN_ON(bh->b_size != blocksize); + err = get_block(inode, block, bh, 1); + if (err) + break; + if (buffer_new(bh)) { + unmap_underlying_metadata(bh->b_bdev, + bh->b_blocknr); + if (PageUptodate(page)) { + clear_buffer_new(bh); + set_buffer_uptodate(bh); + mark_buffer_dirty(bh); + continue; + } + if (block_end > to || block_start < from) + zero_user_segments(page, + to, block_end, + block_start, from); + continue; + } + } + if (PageUptodate(page)) { + if (!buffer_uptodate(bh)) + set_buffer_uptodate(bh); + continue; + } + if (!buffer_uptodate(bh) && !buffer_delay(bh) && + !buffer_unwritten(bh) && + (block_start < from || block_end > to)) { + ll_rw_block(READ, 1, &bh); + *wait_bh++=bh; + } + } + /* + * If we issued read requests - let them complete. + */ + while(wait_bh > wait) { + wait_on_buffer(*--wait_bh); + if (!buffer_uptodate(*wait_bh)) + err = -EIO; + } + if (unlikely(err)) + page_zero_new_buffers(page, from, to); + return err; +} + +static int __block_commit_write(struct inode *inode, struct page *page, + unsigned from, unsigned to) +{ + unsigned block_start, block_end; + int partial = 0; + unsigned blocksize; + struct buffer_head *bh, *head; + + blocksize = 1 << inode->i_blkbits; + + for(bh = head = page_buffers(page), block_start = 0; + bh != head || !block_start; + block_start=block_end, bh = bh->b_this_page) { + block_end = block_start + blocksize; + if (block_end <= from || block_start >= to) { + if (!buffer_uptodate(bh)) + partial = 1; + } else { + set_buffer_uptodate(bh); + mark_buffer_dirty(bh); + } + clear_buffer_new(bh); + } + + /* + * If this is a partial write which happened to make all buffers + * uptodate then we can optimize away a bogus readpage() for + * the next read(). Here we 'discover' whether the page went + * uptodate as a result of this (potentially partial) write. + */ + if (!partial) + SetPageUptodate(page); + return 0; +} + +/* + * block_write_begin takes care of the basic task of block allocation and + * bringing partial write blocks uptodate first. + * + * If *pagep is not NULL, then block_write_begin uses the locked page + * at *pagep rather than allocating its own. In this case, the page will + * not be unlocked or deallocated on failure. + */ +int block_write_begin(struct file *file, struct address_space *mapping, + loff_t pos, unsigned len, unsigned flags, + struct page **pagep, void **fsdata, + get_block_t *get_block) +{ +#ifndef DDE_LINUX + struct inode *inode = mapping->host; + int status = 0; + struct page *page; + pgoff_t index; + unsigned start, end; + int ownpage = 0; + + index = pos >> PAGE_CACHE_SHIFT; + start = pos & (PAGE_CACHE_SIZE - 1); + end = start + len; + + page = *pagep; + if (page == NULL) { + ownpage = 1; + page = grab_cache_page_write_begin(mapping, index, flags); + if (!page) { + status = -ENOMEM; + goto out; + } + *pagep = page; + } else + BUG_ON(!PageLocked(page)); + + status = __block_prepare_write(inode, page, start, end, get_block); + if (unlikely(status)) { + ClearPageUptodate(page); + + if (ownpage) { + unlock_page(page); + page_cache_release(page); + *pagep = NULL; + +#ifndef DDE_LINUX + /* + * prepare_write() may have instantiated a few blocks + * outside i_size. Trim these off again. Don't need + * i_size_read because we hold i_mutex. + */ + if (pos + len > inode->i_size) + vmtruncate(inode, inode->i_size); +#endif + } + } + +out: + return status; +#else + WARN_UNIMPL; + return -1; +#endif +} +EXPORT_SYMBOL(block_write_begin); + +int block_write_end(struct file *file, struct address_space *mapping, + loff_t pos, unsigned len, unsigned copied, + struct page *page, void *fsdata) +{ + struct inode *inode = mapping->host; + unsigned start; + + start = pos & (PAGE_CACHE_SIZE - 1); + + if (unlikely(copied < len)) { + /* + * The buffers that were written will now be uptodate, so we + * don't have to worry about a readpage reading them and + * overwriting a partial write. However if we have encountered + * a short write and only partially written into a buffer, it + * will not be marked uptodate, so a readpage might come in and + * destroy our partial write. + * + * Do the simplest thing, and just treat any short write to a + * non uptodate page as a zero-length write, and force the + * caller to redo the whole thing. + */ + if (!PageUptodate(page)) + copied = 0; + + page_zero_new_buffers(page, start+copied, start+len); + } + flush_dcache_page(page); + + /* This could be a short (even 0-length) commit */ + __block_commit_write(inode, page, start, start+copied); + + return copied; +} +EXPORT_SYMBOL(block_write_end); + +int generic_write_end(struct file *file, struct address_space *mapping, + loff_t pos, unsigned len, unsigned copied, + struct page *page, void *fsdata) +{ + struct inode *inode = mapping->host; + int i_size_changed = 0; + + copied = block_write_end(file, mapping, pos, len, copied, page, fsdata); + + /* + * No need to use i_size_read() here, the i_size + * cannot change under us because we hold i_mutex. + * + * But it's important to update i_size while still holding page lock: + * page writeout could otherwise come in and zero beyond i_size. + */ + if (pos+copied > inode->i_size) { + i_size_write(inode, pos+copied); + i_size_changed = 1; + } + + unlock_page(page); + page_cache_release(page); + + /* + * Don't mark the inode dirty under page lock. First, it unnecessarily + * makes the holding time of page lock longer. Second, it forces lock + * ordering of page lock and transaction start for journaling + * filesystems. + */ + if (i_size_changed) + mark_inode_dirty(inode); + + return copied; +} +EXPORT_SYMBOL(generic_write_end); + +/* + * block_is_partially_uptodate checks whether buffers within a page are + * uptodate or not. + * + * Returns true if all buffers which correspond to a file portion + * we want to read are uptodate. + */ +int block_is_partially_uptodate(struct page *page, read_descriptor_t *desc, + unsigned long from) +{ + struct inode *inode = page->mapping->host; + unsigned block_start, block_end, blocksize; + unsigned to; + struct buffer_head *bh, *head; + int ret = 1; + + if (!page_has_buffers(page)) + return 0; + + blocksize = 1 << inode->i_blkbits; + to = min_t(unsigned, PAGE_CACHE_SIZE - from, desc->count); + to = from + to; + if (from < blocksize && to > PAGE_CACHE_SIZE - blocksize) + return 0; + + head = page_buffers(page); + bh = head; + block_start = 0; + do { + block_end = block_start + blocksize; + if (block_end > from && block_start < to) { + if (!buffer_uptodate(bh)) { + ret = 0; + break; + } + if (block_end >= to) + break; + } + block_start = block_end; + bh = bh->b_this_page; + } while (bh != head); + + return ret; +} +EXPORT_SYMBOL(block_is_partially_uptodate); + +/* + * Generic "read page" function for block devices that have the normal + * get_block functionality. This is most of the block device filesystems. + * Reads the page asynchronously --- the unlock_buffer() and + * set/clear_buffer_uptodate() functions propagate buffer state into the + * page struct once IO has completed. + */ +int block_read_full_page(struct page *page, get_block_t *get_block) +{ + struct inode *inode = page->mapping->host; + sector_t iblock, lblock; + struct buffer_head *bh, *head, *arr[MAX_BUF_PER_PAGE]; + unsigned int blocksize; + int nr, i; + int fully_mapped = 1; + + BUG_ON(!PageLocked(page)); + blocksize = 1 << inode->i_blkbits; + if (!page_has_buffers(page)) + create_empty_buffers(page, blocksize, 0); + head = page_buffers(page); + + iblock = (sector_t)page->index << (PAGE_CACHE_SHIFT - inode->i_blkbits); + lblock = (i_size_read(inode)+blocksize-1) >> inode->i_blkbits; + bh = head; + nr = 0; + i = 0; + + do { + if (buffer_uptodate(bh)) + continue; + + if (!buffer_mapped(bh)) { + int err = 0; + + fully_mapped = 0; + if (iblock < lblock) { + WARN_ON(bh->b_size != blocksize); + err = get_block(inode, iblock, bh, 0); + if (err) + SetPageError(page); + } + if (!buffer_mapped(bh)) { + zero_user(page, i * blocksize, blocksize); + if (!err) + set_buffer_uptodate(bh); + continue; + } + /* + * get_block() might have updated the buffer + * synchronously + */ + if (buffer_uptodate(bh)) + continue; + } + arr[nr++] = bh; + } while (i++, iblock++, (bh = bh->b_this_page) != head); + + if (fully_mapped) + SetPageMappedToDisk(page); + + if (!nr) { + /* + * All buffers are uptodate - we can set the page uptodate + * as well. But not if get_block() returned an error. + */ + if (!PageError(page)) + SetPageUptodate(page); + unlock_page(page); + return 0; + } + + /* Stage two: lock the buffers */ + for (i = 0; i < nr; i++) { + bh = arr[i]; + lock_buffer(bh); + mark_buffer_async_read(bh); + } + + /* + * Stage 3: start the IO. Check for uptodateness + * inside the buffer lock in case another process reading + * the underlying blockdev brought it uptodate (the sct fix). + */ + for (i = 0; i < nr; i++) { + bh = arr[i]; + if (buffer_uptodate(bh)) + end_buffer_async_read(bh, 1); + else + submit_bh(READ, bh); + } + return 0; +} + +/* utility function for filesystems that need to do work on expanding + * truncates. Uses filesystem pagecache writes to allow the filesystem to + * deal with the hole. + */ +int generic_cont_expand_simple(struct inode *inode, loff_t size) +{ + struct address_space *mapping = inode->i_mapping; + struct page *page; + void *fsdata; + unsigned long limit; + int err; + + err = -EFBIG; + limit = current->signal->rlim[RLIMIT_FSIZE].rlim_cur; + if (limit != RLIM_INFINITY && size > (loff_t)limit) { + send_sig(SIGXFSZ, current, 0); + goto out; + } + if (size > inode->i_sb->s_maxbytes) + goto out; + + err = pagecache_write_begin(NULL, mapping, size, 0, + AOP_FLAG_UNINTERRUPTIBLE|AOP_FLAG_CONT_EXPAND, + &page, &fsdata); + if (err) + goto out; + + err = pagecache_write_end(NULL, mapping, size, 0, 0, page, fsdata); + BUG_ON(err > 0); + +out: + return err; +} + +static int cont_expand_zero(struct file *file, struct address_space *mapping, + loff_t pos, loff_t *bytes) +{ + struct inode *inode = mapping->host; + unsigned blocksize = 1 << inode->i_blkbits; + struct page *page; + void *fsdata; + pgoff_t index, curidx; + loff_t curpos; + unsigned zerofrom, offset, len; + int err = 0; + + index = pos >> PAGE_CACHE_SHIFT; + offset = pos & ~PAGE_CACHE_MASK; + + while (index > (curidx = (curpos = *bytes)>>PAGE_CACHE_SHIFT)) { + zerofrom = curpos & ~PAGE_CACHE_MASK; + if (zerofrom & (blocksize-1)) { + *bytes |= (blocksize-1); + (*bytes)++; + } + len = PAGE_CACHE_SIZE - zerofrom; + + err = pagecache_write_begin(file, mapping, curpos, len, + AOP_FLAG_UNINTERRUPTIBLE, + &page, &fsdata); + if (err) + goto out; + zero_user(page, zerofrom, len); + err = pagecache_write_end(file, mapping, curpos, len, len, + page, fsdata); + if (err < 0) + goto out; + BUG_ON(err != len); + err = 0; + + balance_dirty_pages_ratelimited(mapping); + } + + /* page covers the boundary, find the boundary offset */ + if (index == curidx) { + zerofrom = curpos & ~PAGE_CACHE_MASK; + /* if we will expand the thing last block will be filled */ + if (offset <= zerofrom) { + goto out; + } + if (zerofrom & (blocksize-1)) { + *bytes |= (blocksize-1); + (*bytes)++; + } + len = offset - zerofrom; + + err = pagecache_write_begin(file, mapping, curpos, len, + AOP_FLAG_UNINTERRUPTIBLE, + &page, &fsdata); + if (err) + goto out; + zero_user(page, zerofrom, len); + err = pagecache_write_end(file, mapping, curpos, len, len, + page, fsdata); + if (err < 0) + goto out; + BUG_ON(err != len); + err = 0; + } +out: + return err; +} + +/* + * For moronic filesystems that do not allow holes in file. + * We may have to extend the file. + */ +int cont_write_begin(struct file *file, struct address_space *mapping, + loff_t pos, unsigned len, unsigned flags, + struct page **pagep, void **fsdata, + get_block_t *get_block, loff_t *bytes) +{ + struct inode *inode = mapping->host; + unsigned blocksize = 1 << inode->i_blkbits; + unsigned zerofrom; + int err; + + err = cont_expand_zero(file, mapping, pos, bytes); + if (err) + goto out; + + zerofrom = *bytes & ~PAGE_CACHE_MASK; + if (pos+len > *bytes && zerofrom & (blocksize-1)) { + *bytes |= (blocksize-1); + (*bytes)++; + } + + *pagep = NULL; + err = block_write_begin(file, mapping, pos, len, + flags, pagep, fsdata, get_block); +out: + return err; +} + +int block_prepare_write(struct page *page, unsigned from, unsigned to, + get_block_t *get_block) +{ + struct inode *inode = page->mapping->host; + int err = __block_prepare_write(inode, page, from, to, get_block); + if (err) + ClearPageUptodate(page); + return err; +} + +int block_commit_write(struct page *page, unsigned from, unsigned to) +{ + struct inode *inode = page->mapping->host; + __block_commit_write(inode,page,from,to); + return 0; +} + +/* + * block_page_mkwrite() is not allowed to change the file size as it gets + * called from a page fault handler when a page is first dirtied. Hence we must + * be careful to check for EOF conditions here. We set the page up correctly + * for a written page which means we get ENOSPC checking when writing into + * holes and correct delalloc and unwritten extent mapping on filesystems that + * support these features. + * + * We are not allowed to take the i_mutex here so we have to play games to + * protect against truncate races as the page could now be beyond EOF. Because + * vmtruncate() writes the inode size before removing pages, once we have the + * page lock we can determine safely if the page is beyond EOF. If it is not + * beyond EOF, then the page is guaranteed safe against truncation until we + * unlock the page. + */ +int +block_page_mkwrite(struct vm_area_struct *vma, struct page *page, + get_block_t get_block) +{ + struct inode *inode = vma->vm_file->f_path.dentry->d_inode; + unsigned long end; + loff_t size; + int ret = -EINVAL; + + lock_page(page); + size = i_size_read(inode); + if ((page->mapping != inode->i_mapping) || + (page_offset(page) > size)) { + /* page got truncated out from underneath us */ + goto out_unlock; + } + + /* page is wholly or partially inside EOF */ + if (((page->index + 1) << PAGE_CACHE_SHIFT) > size) + end = size & ~PAGE_CACHE_MASK; + else + end = PAGE_CACHE_SIZE; + + ret = block_prepare_write(page, 0, end, get_block); + if (!ret) + ret = block_commit_write(page, 0, end); + +out_unlock: + unlock_page(page); + return ret; +} + +/* + * nobh_write_begin()'s prereads are special: the buffer_heads are freed + * immediately, while under the page lock. So it needs a special end_io + * handler which does not touch the bh after unlocking it. + */ +static void end_buffer_read_nobh(struct buffer_head *bh, int uptodate) +{ + __end_buffer_read_notouch(bh, uptodate); +} + +/* + * Attach the singly-linked list of buffers created by nobh_write_begin, to + * the page (converting it to circular linked list and taking care of page + * dirty races). + */ +static void attach_nobh_buffers(struct page *page, struct buffer_head *head) +{ + struct buffer_head *bh; + + BUG_ON(!PageLocked(page)); + + spin_lock(&page->mapping->private_lock); + bh = head; + do { + if (PageDirty(page)) + set_buffer_dirty(bh); + if (!bh->b_this_page) + bh->b_this_page = head; + bh = bh->b_this_page; + } while (bh != head); + attach_page_buffers(page, head); + spin_unlock(&page->mapping->private_lock); +} + +/* + * On entry, the page is fully not uptodate. + * On exit the page is fully uptodate in the areas outside (from,to) + */ +int nobh_write_begin(struct file *file, struct address_space *mapping, + loff_t pos, unsigned len, unsigned flags, + struct page **pagep, void **fsdata, + get_block_t *get_block) +{ + struct inode *inode = mapping->host; + const unsigned blkbits = inode->i_blkbits; + const unsigned blocksize = 1 << blkbits; + struct buffer_head *head, *bh; + struct page *page; + pgoff_t index; + unsigned from, to; + unsigned block_in_page; + unsigned block_start, block_end; + sector_t block_in_file; + int nr_reads = 0; + int ret = 0; + int is_mapped_to_disk = 1; + + index = pos >> PAGE_CACHE_SHIFT; + from = pos & (PAGE_CACHE_SIZE - 1); + to = from + len; + + page = grab_cache_page_write_begin(mapping, index, flags); + if (!page) + return -ENOMEM; + *pagep = page; + *fsdata = NULL; + + if (page_has_buffers(page)) { + unlock_page(page); + page_cache_release(page); + *pagep = NULL; + return block_write_begin(file, mapping, pos, len, flags, pagep, + fsdata, get_block); + } + + if (PageMappedToDisk(page)) + return 0; + + /* + * Allocate buffers so that we can keep track of state, and potentially + * attach them to the page if an error occurs. In the common case of + * no error, they will just be freed again without ever being attached + * to the page (which is all OK, because we're under the page lock). + * + * Be careful: the buffer linked list is a NULL terminated one, rather + * than the circular one we're used to. + */ + head = alloc_page_buffers(page, blocksize, 0); + if (!head) { + ret = -ENOMEM; + goto out_release; + } + + block_in_file = (sector_t)page->index << (PAGE_CACHE_SHIFT - blkbits); + + /* + * We loop across all blocks in the page, whether or not they are + * part of the affected region. This is so we can discover if the + * page is fully mapped-to-disk. + */ + for (block_start = 0, block_in_page = 0, bh = head; + block_start < PAGE_CACHE_SIZE; + block_in_page++, block_start += blocksize, bh = bh->b_this_page) { + int create; + + block_end = block_start + blocksize; + bh->b_state = 0; + create = 1; + if (block_start >= to) + create = 0; + ret = get_block(inode, block_in_file + block_in_page, + bh, create); + if (ret) + goto failed; + if (!buffer_mapped(bh)) + is_mapped_to_disk = 0; + if (buffer_new(bh)) + unmap_underlying_metadata(bh->b_bdev, bh->b_blocknr); + if (PageUptodate(page)) { + set_buffer_uptodate(bh); + continue; + } + if (buffer_new(bh) || !buffer_mapped(bh)) { + zero_user_segments(page, block_start, from, + to, block_end); + continue; + } + if (buffer_uptodate(bh)) + continue; /* reiserfs does this */ + if (block_start < from || block_end > to) { + lock_buffer(bh); + bh->b_end_io = end_buffer_read_nobh; + submit_bh(READ, bh); + nr_reads++; + } + } + + if (nr_reads) { + /* + * The page is locked, so these buffers are protected from + * any VM or truncate activity. Hence we don't need to care + * for the buffer_head refcounts. + */ + for (bh = head; bh; bh = bh->b_this_page) { + wait_on_buffer(bh); + if (!buffer_uptodate(bh)) + ret = -EIO; + } + if (ret) + goto failed; + } + + if (is_mapped_to_disk) + SetPageMappedToDisk(page); + + *fsdata = head; /* to be released by nobh_write_end */ + + return 0; + +failed: + BUG_ON(!ret); + /* + * Error recovery is a bit difficult. We need to zero out blocks that + * were newly allocated, and dirty them to ensure they get written out. + * Buffers need to be attached to the page at this point, otherwise + * the handling of potential IO errors during writeout would be hard + * (could try doing synchronous writeout, but what if that fails too?) + */ + attach_nobh_buffers(page, head); + page_zero_new_buffers(page, from, to); + +out_release: + unlock_page(page); + page_cache_release(page); + *pagep = NULL; + + if (pos + len > inode->i_size) + vmtruncate(inode, inode->i_size); + + return ret; +} +EXPORT_SYMBOL(nobh_write_begin); + +int nobh_write_end(struct file *file, struct address_space *mapping, + loff_t pos, unsigned len, unsigned copied, + struct page *page, void *fsdata) +{ + struct inode *inode = page->mapping->host; + struct buffer_head *head = fsdata; + struct buffer_head *bh; + BUG_ON(fsdata != NULL && page_has_buffers(page)); + + if (unlikely(copied < len) && head) + attach_nobh_buffers(page, head); + if (page_has_buffers(page)) + return generic_write_end(file, mapping, pos, len, + copied, page, fsdata); + + SetPageUptodate(page); + set_page_dirty(page); + if (pos+copied > inode->i_size) { + i_size_write(inode, pos+copied); + mark_inode_dirty(inode); + } + + unlock_page(page); + page_cache_release(page); + + while (head) { + bh = head; + head = head->b_this_page; + free_buffer_head(bh); + } + + return copied; +} +EXPORT_SYMBOL(nobh_write_end); + +/* + * nobh_writepage() - based on block_full_write_page() except + * that it tries to operate without attaching bufferheads to + * the page. + */ +int nobh_writepage(struct page *page, get_block_t *get_block, + struct writeback_control *wbc) +{ + struct inode * const inode = page->mapping->host; + loff_t i_size = i_size_read(inode); + const pgoff_t end_index = i_size >> PAGE_CACHE_SHIFT; + unsigned offset; + int ret; + + /* Is the page fully inside i_size? */ + if (page->index < end_index) + goto out; + + /* Is the page fully outside i_size? (truncate in progress) */ + offset = i_size & (PAGE_CACHE_SIZE-1); + if (page->index >= end_index+1 || !offset) { + /* + * The page may have dirty, unmapped buffers. For example, + * they may have been added in ext3_writepage(). Make them + * freeable here, so the page does not leak. + */ +#if 0 + /* Not really sure about this - do we need this ? */ + if (page->mapping->a_ops->invalidatepage) + page->mapping->a_ops->invalidatepage(page, offset); +#endif + unlock_page(page); + return 0; /* don't care */ + } + + /* + * The page straddles i_size. It must be zeroed out on each and every + * writepage invocation because it may be mmapped. "A file is mapped + * in multiples of the page size. For a file that is not a multiple of + * the page size, the remaining memory is zeroed when mapped, and + * writes to that region are not written out to the file." + */ + zero_user_segment(page, offset, PAGE_CACHE_SIZE); +out: + ret = mpage_writepage(page, get_block, wbc); + if (ret == -EAGAIN) + ret = __block_write_full_page(inode, page, get_block, wbc); + return ret; +} +EXPORT_SYMBOL(nobh_writepage); + +int nobh_truncate_page(struct address_space *mapping, + loff_t from, get_block_t *get_block) +{ + pgoff_t index = from >> PAGE_CACHE_SHIFT; + unsigned offset = from & (PAGE_CACHE_SIZE-1); + unsigned blocksize; + sector_t iblock; + unsigned length, pos; + struct inode *inode = mapping->host; + struct page *page; + struct buffer_head map_bh; + int err; + + blocksize = 1 << inode->i_blkbits; + length = offset & (blocksize - 1); + + /* Block boundary? Nothing to do */ + if (!length) + return 0; + + length = blocksize - length; + iblock = (sector_t)index << (PAGE_CACHE_SHIFT - inode->i_blkbits); + + page = grab_cache_page(mapping, index); + err = -ENOMEM; + if (!page) + goto out; + + if (page_has_buffers(page)) { +has_buffers: + unlock_page(page); + page_cache_release(page); + return block_truncate_page(mapping, from, get_block); + } + + /* Find the buffer that contains "offset" */ + pos = blocksize; + while (offset >= pos) { + iblock++; + pos += blocksize; + } + + err = get_block(inode, iblock, &map_bh, 0); + if (err) + goto unlock; + /* unmapped? It's a hole - nothing to do */ + if (!buffer_mapped(&map_bh)) + goto unlock; + + /* Ok, it's mapped. Make sure it's up-to-date */ + if (!PageUptodate(page)) { + err = mapping->a_ops->readpage(NULL, page); + if (err) { + page_cache_release(page); + goto out; + } + lock_page(page); + if (!PageUptodate(page)) { + err = -EIO; + goto unlock; + } + if (page_has_buffers(page)) + goto has_buffers; + } + zero_user(page, offset, length); + set_page_dirty(page); + err = 0; + +unlock: + unlock_page(page); + page_cache_release(page); +out: + return err; +} +EXPORT_SYMBOL(nobh_truncate_page); + +int block_truncate_page(struct address_space *mapping, + loff_t from, get_block_t *get_block) +{ + pgoff_t index = from >> PAGE_CACHE_SHIFT; + unsigned offset = from & (PAGE_CACHE_SIZE-1); + unsigned blocksize; + sector_t iblock; + unsigned length, pos; + struct inode *inode = mapping->host; + struct page *page; + struct buffer_head *bh; + int err; + + blocksize = 1 << inode->i_blkbits; + length = offset & (blocksize - 1); + + /* Block boundary? Nothing to do */ + if (!length) + return 0; + + length = blocksize - length; + iblock = (sector_t)index << (PAGE_CACHE_SHIFT - inode->i_blkbits); + + page = grab_cache_page(mapping, index); + err = -ENOMEM; + if (!page) + goto out; + + if (!page_has_buffers(page)) + create_empty_buffers(page, blocksize, 0); + + /* Find the buffer that contains "offset" */ + bh = page_buffers(page); + pos = blocksize; + while (offset >= pos) { + bh = bh->b_this_page; + iblock++; + pos += blocksize; + } + + err = 0; + if (!buffer_mapped(bh)) { + WARN_ON(bh->b_size != blocksize); + err = get_block(inode, iblock, bh, 0); + if (err) + goto unlock; + /* unmapped? It's a hole - nothing to do */ + if (!buffer_mapped(bh)) + goto unlock; + } + + /* Ok, it's mapped. Make sure it's up-to-date */ + if (PageUptodate(page)) + set_buffer_uptodate(bh); + + if (!buffer_uptodate(bh) && !buffer_delay(bh) && !buffer_unwritten(bh)) { + err = -EIO; + ll_rw_block(READ, 1, &bh); + wait_on_buffer(bh); + /* Uhhuh. Read error. Complain and punt. */ + if (!buffer_uptodate(bh)) + goto unlock; + } + + zero_user(page, offset, length); + mark_buffer_dirty(bh); + err = 0; + +unlock: + unlock_page(page); + page_cache_release(page); +out: + return err; +} + +/* + * The generic ->writepage function for buffer-backed address_spaces + */ +int block_write_full_page(struct page *page, get_block_t *get_block, + struct writeback_control *wbc) +{ + struct inode * const inode = page->mapping->host; + loff_t i_size = i_size_read(inode); + const pgoff_t end_index = i_size >> PAGE_CACHE_SHIFT; + unsigned offset; + + /* Is the page fully inside i_size? */ + if (page->index < end_index) + return __block_write_full_page(inode, page, get_block, wbc); + + /* Is the page fully outside i_size? (truncate in progress) */ + offset = i_size & (PAGE_CACHE_SIZE-1); + if (page->index >= end_index+1 || !offset) { + /* + * The page may have dirty, unmapped buffers. For example, + * they may have been added in ext3_writepage(). Make them + * freeable here, so the page does not leak. + */ + do_invalidatepage(page, 0); + unlock_page(page); + return 0; /* don't care */ + } + + /* + * The page straddles i_size. It must be zeroed out on each and every + * writepage invokation because it may be mmapped. "A file is mapped + * in multiples of the page size. For a file that is not a multiple of + * the page size, the remaining memory is zeroed when mapped, and + * writes to that region are not written out to the file." + */ + zero_user_segment(page, offset, PAGE_CACHE_SIZE); + return __block_write_full_page(inode, page, get_block, wbc); +} + +sector_t generic_block_bmap(struct address_space *mapping, sector_t block, + get_block_t *get_block) +{ + struct buffer_head tmp; + struct inode *inode = mapping->host; + tmp.b_state = 0; + tmp.b_blocknr = 0; + tmp.b_size = 1 << inode->i_blkbits; + get_block(inode, block, &tmp, 0); + return tmp.b_blocknr; +} + +static void end_bio_bh_io_sync(struct bio *bio, int err) +{ + struct buffer_head *bh = bio->bi_private; + + if (err == -EOPNOTSUPP) { + set_bit(BIO_EOPNOTSUPP, &bio->bi_flags); + set_bit(BH_Eopnotsupp, &bh->b_state); + } + + if (unlikely (test_bit(BIO_QUIET,&bio->bi_flags))) + set_bit(BH_Quiet, &bh->b_state); + + bh->b_end_io(bh, test_bit(BIO_UPTODATE, &bio->bi_flags)); + bio_put(bio); +} + +int submit_bh(int rw, struct buffer_head * bh) +{ + struct bio *bio; + int ret = 0; + + BUG_ON(!buffer_locked(bh)); + BUG_ON(!buffer_mapped(bh)); + BUG_ON(!bh->b_end_io); + + /* + * Mask in barrier bit for a write (could be either a WRITE or a + * WRITE_SYNC + */ + if (buffer_ordered(bh) && (rw & WRITE)) + rw |= WRITE_BARRIER; + + /* + * Only clear out a write error when rewriting + */ + if (test_set_buffer_req(bh) && (rw & WRITE)) + clear_buffer_write_io_error(bh); + + /* + * from here on down, it's all bio -- do the initial mapping, + * submit_bio -> generic_make_request may further map this bio around + */ + bio = bio_alloc(GFP_NOIO, 1); + + bio->bi_sector = bh->b_blocknr * (bh->b_size >> 9); + bio->bi_bdev = bh->b_bdev; + bio->bi_io_vec[0].bv_page = bh->b_page; + bio->bi_io_vec[0].bv_len = bh->b_size; + bio->bi_io_vec[0].bv_offset = bh_offset(bh); + + bio->bi_vcnt = 1; + bio->bi_idx = 0; + bio->bi_size = bh->b_size; + + bio->bi_end_io = end_bio_bh_io_sync; + bio->bi_private = bh; + + bio_get(bio); + submit_bio(rw, bio); + + if (bio_flagged(bio, BIO_EOPNOTSUPP)) + ret = -EOPNOTSUPP; + + bio_put(bio); + return ret; +} + +/** + * ll_rw_block: low-level access to block devices (DEPRECATED) + * @rw: whether to %READ or %WRITE or %SWRITE or maybe %READA (readahead) + * @nr: number of &struct buffer_heads in the array + * @bhs: array of pointers to &struct buffer_head + * + * ll_rw_block() takes an array of pointers to &struct buffer_heads, and + * requests an I/O operation on them, either a %READ or a %WRITE. The third + * %SWRITE is like %WRITE only we make sure that the *current* data in buffers + * are sent to disk. The fourth %READA option is described in the documentation + * for generic_make_request() which ll_rw_block() calls. + * + * This function drops any buffer that it cannot get a lock on (with the + * BH_Lock state bit) unless SWRITE is required, any buffer that appears to be + * clean when doing a write request, and any buffer that appears to be + * up-to-date when doing read request. Further it marks as clean buffers that + * are processed for writing (the buffer cache won't assume that they are + * actually clean until the buffer gets unlocked). + * + * ll_rw_block sets b_end_io to simple completion handler that marks + * the buffer up-to-date (if approriate), unlocks the buffer and wakes + * any waiters. + * + * All of the buffers must be for the same device, and must also be a + * multiple of the current approved size for the device. + */ +void ll_rw_block(int rw, int nr, struct buffer_head *bhs[]) +{ + int i; + + for (i = 0; i < nr; i++) { + struct buffer_head *bh = bhs[i]; + + if (rw == SWRITE || rw == SWRITE_SYNC) + lock_buffer(bh); + else if (!trylock_buffer(bh)) + continue; + + if (rw == WRITE || rw == SWRITE || rw == SWRITE_SYNC) { + if (test_clear_buffer_dirty(bh)) { + bh->b_end_io = end_buffer_write_sync; + get_bh(bh); + if (rw == SWRITE_SYNC) + submit_bh(WRITE_SYNC, bh); + else + submit_bh(WRITE, bh); + continue; + } + } else { + if (!buffer_uptodate(bh)) { + bh->b_end_io = end_buffer_read_sync; + get_bh(bh); + submit_bh(rw, bh); + continue; + } + } + unlock_buffer(bh); + } +} + +/* + * For a data-integrity writeout, we need to wait upon any in-progress I/O + * and then start new I/O and then wait upon it. The caller must have a ref on + * the buffer_head. + */ +int sync_dirty_buffer(struct buffer_head *bh) +{ + int ret = 0; + + WARN_ON(atomic_read(&bh->b_count) < 1); + lock_buffer(bh); + if (test_clear_buffer_dirty(bh)) { + get_bh(bh); + bh->b_end_io = end_buffer_write_sync; + ret = submit_bh(WRITE, bh); + wait_on_buffer(bh); + if (buffer_eopnotsupp(bh)) { + clear_buffer_eopnotsupp(bh); + ret = -EOPNOTSUPP; + } + if (!ret && !buffer_uptodate(bh)) + ret = -EIO; + } else { + unlock_buffer(bh); + } + return ret; +} + +/* + * try_to_free_buffers() checks if all the buffers on this particular page + * are unused, and releases them if so. + * + * Exclusion against try_to_free_buffers may be obtained by either + * locking the page or by holding its mapping's private_lock. + * + * If the page is dirty but all the buffers are clean then we need to + * be sure to mark the page clean as well. This is because the page + * may be against a block device, and a later reattachment of buffers + * to a dirty page will set *all* buffers dirty. Which would corrupt + * filesystem data on the same device. + * + * The same applies to regular filesystem pages: if all the buffers are + * clean then we set the page clean and proceed. To do that, we require + * total exclusion from __set_page_dirty_buffers(). That is obtained with + * private_lock. + * + * try_to_free_buffers() is non-blocking. + */ +static inline int buffer_busy(struct buffer_head *bh) +{ + return atomic_read(&bh->b_count) | + (bh->b_state & ((1 << BH_Dirty) | (1 << BH_Lock))); +} + +static int +drop_buffers(struct page *page, struct buffer_head **buffers_to_free) +{ + struct buffer_head *head = page_buffers(page); + struct buffer_head *bh; + + bh = head; + do { + if (buffer_write_io_error(bh) && page->mapping) + set_bit(AS_EIO, &page->mapping->flags); + if (buffer_busy(bh)) + goto failed; + bh = bh->b_this_page; + } while (bh != head); + + do { + struct buffer_head *next = bh->b_this_page; + + if (bh->b_assoc_map) + __remove_assoc_queue(bh); + bh = next; + } while (bh != head); + *buffers_to_free = head; + __clear_page_buffers(page); + return 1; +failed: + return 0; +} + +int try_to_free_buffers(struct page *page) +{ + struct address_space * const mapping = page->mapping; + struct buffer_head *buffers_to_free = NULL; + int ret = 0; + + BUG_ON(!PageLocked(page)); + if (PageWriteback(page)) + return 0; + + if (mapping == NULL) { /* can this still happen? */ + ret = drop_buffers(page, &buffers_to_free); + goto out; + } + + spin_lock(&mapping->private_lock); + ret = drop_buffers(page, &buffers_to_free); + + /* + * If the filesystem writes its buffers by hand (eg ext3) + * then we can have clean buffers against a dirty page. We + * clean the page here; otherwise the VM will never notice + * that the filesystem did any IO at all. + * + * Also, during truncate, discard_buffer will have marked all + * the page's buffers clean. We discover that here and clean + * the page also. + * + * private_lock must be held over this entire operation in order + * to synchronise against __set_page_dirty_buffers and prevent the + * dirty bit from being lost. + */ +#ifndef DDE_LINUX + if (ret) + cancel_dirty_page(page, PAGE_CACHE_SIZE); +#endif + spin_unlock(&mapping->private_lock); +out: + if (buffers_to_free) { + struct buffer_head *bh = buffers_to_free; + + do { + struct buffer_head *next = bh->b_this_page; + free_buffer_head(bh); + bh = next; + } while (bh != buffers_to_free); + } + return ret; +} +EXPORT_SYMBOL(try_to_free_buffers); + +void block_sync_page(struct page *page) +{ + struct address_space *mapping; + + smp_mb(); + mapping = page_mapping(page); + if (mapping) + blk_run_backing_dev(mapping->backing_dev_info, page); +} + +/* + * There are no bdflush tunables left. But distributions are + * still running obsolete flush daemons, so we terminate them here. + * + * Use of bdflush() is deprecated and will be removed in a future kernel. + * The `pdflush' kernel threads fully replace bdflush daemons and this call. + */ +SYSCALL_DEFINE2(bdflush, int, func, long, data) +{ + static int msg_count; + + if (!capable(CAP_SYS_ADMIN)) + return -EPERM; + + if (msg_count < 5) { + msg_count++; + printk(KERN_INFO + "warning: process `%s' used the obsolete bdflush" + " system call\n", current->comm); + printk(KERN_INFO "Fix your initscripts?\n"); + } + + if (func == 1) + do_exit(0); + return 0; +} + +/* + * Buffer-head allocation + */ +static struct kmem_cache *bh_cachep; + +/* + * Once the number of bh's in the machine exceeds this level, we start + * stripping them in writeback. + */ +static int max_buffer_heads; + +int buffer_heads_over_limit; + +struct bh_accounting { + int nr; /* Number of live bh's */ + int ratelimit; /* Limit cacheline bouncing */ +}; + +static DEFINE_PER_CPU(struct bh_accounting, bh_accounting) = {0, 0}; + +static void recalc_bh_state(void) +{ + int i; + int tot = 0; + + if (__get_cpu_var(bh_accounting).ratelimit++ < 4096) + return; + __get_cpu_var(bh_accounting).ratelimit = 0; + for_each_online_cpu(i) + tot += per_cpu(bh_accounting, i).nr; + buffer_heads_over_limit = (tot > max_buffer_heads); +} + +struct buffer_head *alloc_buffer_head(gfp_t gfp_flags) +{ + struct buffer_head *ret = kmem_cache_alloc(bh_cachep, gfp_flags); + if (ret) { + INIT_LIST_HEAD(&ret->b_assoc_buffers); + get_cpu_var(bh_accounting).nr++; + recalc_bh_state(); + put_cpu_var(bh_accounting); + } + return ret; +} +EXPORT_SYMBOL(alloc_buffer_head); + +void free_buffer_head(struct buffer_head *bh) +{ + BUG_ON(!list_empty(&bh->b_assoc_buffers)); + kmem_cache_free(bh_cachep, bh); + get_cpu_var(bh_accounting).nr--; + recalc_bh_state(); + put_cpu_var(bh_accounting); +} +EXPORT_SYMBOL(free_buffer_head); + +static void buffer_exit_cpu(int cpu) +{ + int i; + struct bh_lru *b = &per_cpu(bh_lrus, cpu); + + for (i = 0; i < BH_LRU_SIZE; i++) { + brelse(b->bhs[i]); + b->bhs[i] = NULL; + } + get_cpu_var(bh_accounting).nr += per_cpu(bh_accounting, cpu).nr; + per_cpu(bh_accounting, cpu).nr = 0; + put_cpu_var(bh_accounting); +} + +static int buffer_cpu_notify(struct notifier_block *self, + unsigned long action, void *hcpu) +{ + if (action == CPU_DEAD || action == CPU_DEAD_FROZEN) + buffer_exit_cpu((unsigned long)hcpu); + return NOTIFY_OK; +} + +/** + * bh_uptodate_or_lock - Test whether the buffer is uptodate + * @bh: struct buffer_head + * + * Return true if the buffer is up-to-date and false, + * with the buffer locked, if not. + */ +int bh_uptodate_or_lock(struct buffer_head *bh) +{ + if (!buffer_uptodate(bh)) { + lock_buffer(bh); + if (!buffer_uptodate(bh)) + return 0; + unlock_buffer(bh); + } + return 1; +} +EXPORT_SYMBOL(bh_uptodate_or_lock); + +/** + * bh_submit_read - Submit a locked buffer for reading + * @bh: struct buffer_head + * + * Returns zero on success and -EIO on error. + */ +int bh_submit_read(struct buffer_head *bh) +{ + BUG_ON(!buffer_locked(bh)); + + if (buffer_uptodate(bh)) { + unlock_buffer(bh); + return 0; + } + + get_bh(bh); + bh->b_end_io = end_buffer_read_sync; + submit_bh(READ, bh); + wait_on_buffer(bh); + if (buffer_uptodate(bh)) + return 0; + return -EIO; +} +EXPORT_SYMBOL(bh_submit_read); + +static void +init_buffer_head(void *data) +{ + struct buffer_head *bh = data; + + memset(bh, 0, sizeof(*bh)); + INIT_LIST_HEAD(&bh->b_assoc_buffers); +} + +void __init buffer_init(void) +{ + int nrpages; + + bh_cachep = kmem_cache_create("buffer_head", + sizeof(struct buffer_head), 0, + (SLAB_RECLAIM_ACCOUNT|SLAB_PANIC| + SLAB_MEM_SPREAD), + init_buffer_head); + + /* + * Limit the bh occupancy to 10% of ZONE_NORMAL + */ + nrpages = (nr_free_buffer_pages() * 10) / 100; + max_buffer_heads = nrpages * (PAGE_SIZE / sizeof(struct buffer_head)); + hotcpu_notifier(buffer_cpu_notify, 0); +} + +EXPORT_SYMBOL(__bforget); +EXPORT_SYMBOL(__brelse); +EXPORT_SYMBOL(__wait_on_buffer); +EXPORT_SYMBOL(block_commit_write); +EXPORT_SYMBOL(block_prepare_write); +EXPORT_SYMBOL(block_page_mkwrite); +EXPORT_SYMBOL(block_read_full_page); +EXPORT_SYMBOL(block_sync_page); +EXPORT_SYMBOL(block_truncate_page); +EXPORT_SYMBOL(block_write_full_page); +EXPORT_SYMBOL(cont_write_begin); +EXPORT_SYMBOL(end_buffer_read_sync); +EXPORT_SYMBOL(end_buffer_write_sync); +EXPORT_SYMBOL(file_fsync); +EXPORT_SYMBOL(fsync_bdev); +EXPORT_SYMBOL(generic_block_bmap); +EXPORT_SYMBOL(generic_cont_expand_simple); +EXPORT_SYMBOL(init_buffer); +EXPORT_SYMBOL(invalidate_bdev); +EXPORT_SYMBOL(ll_rw_block); +EXPORT_SYMBOL(mark_buffer_dirty); +EXPORT_SYMBOL(submit_bh); +EXPORT_SYMBOL(sync_dirty_buffer); +EXPORT_SYMBOL(unlock_buffer); diff --git a/libdde_linux26/lib/src/fs/char_dev.c b/libdde_linux26/lib/src/fs/char_dev.c new file mode 100644 index 00000000..3b8e8b3d --- /dev/null +++ b/libdde_linux26/lib/src/fs/char_dev.c @@ -0,0 +1,572 @@ +/* + * linux/fs/char_dev.c + * + * Copyright (C) 1991, 1992 Linus Torvalds + */ + +#include <linux/init.h> +#include <linux/fs.h> +#include <linux/kdev_t.h> +#include <linux/slab.h> +#include <linux/string.h> + +#include <linux/major.h> +#include <linux/errno.h> +#include <linux/module.h> +#include <linux/smp_lock.h> +#include <linux/seq_file.h> + +#include <linux/kobject.h> +#include <linux/kobj_map.h> +#include <linux/cdev.h> +#include <linux/mutex.h> +#include <linux/backing-dev.h> + +#ifdef CONFIG_KMOD +#include <linux/kmod.h> +#endif +#include "internal.h" + +#ifdef DDE_LINUX +#include "local.h" +#endif + +/* + * capabilities for /dev/mem, /dev/kmem and similar directly mappable character + * devices + * - permits shared-mmap for read, write and/or exec + * - does not permit private mmap in NOMMU mode (can't do COW) + * - no readahead or I/O queue unplugging required + */ +struct backing_dev_info directly_mappable_cdev_bdi = { + .capabilities = ( +#ifdef CONFIG_MMU + /* permit private copies of the data to be taken */ + BDI_CAP_MAP_COPY | +#endif + /* permit direct mmap, for read, write or exec */ + BDI_CAP_MAP_DIRECT | + BDI_CAP_READ_MAP | BDI_CAP_WRITE_MAP | BDI_CAP_EXEC_MAP), +}; + +static struct kobj_map *cdev_map; + +static DEFINE_MUTEX(chrdevs_lock); + +static struct char_device_struct { + struct char_device_struct *next; + unsigned int major; + unsigned int baseminor; + int minorct; + char name[64]; + struct cdev *cdev; /* will die */ +} *chrdevs[CHRDEV_MAJOR_HASH_SIZE]; + +/* index in the above */ +static inline int major_to_index(int major) +{ + return major % CHRDEV_MAJOR_HASH_SIZE; +} + +#ifdef CONFIG_PROC_FS + +void chrdev_show(struct seq_file *f, off_t offset) +{ + struct char_device_struct *cd; + + if (offset < CHRDEV_MAJOR_HASH_SIZE) { + mutex_lock(&chrdevs_lock); + for (cd = chrdevs[offset]; cd; cd = cd->next) + seq_printf(f, "%3d %s\n", cd->major, cd->name); + mutex_unlock(&chrdevs_lock); + } +} + +#endif /* CONFIG_PROC_FS */ + +/* + * Register a single major with a specified minor range. + * + * If major == 0 this functions will dynamically allocate a major and return + * its number. + * + * If major > 0 this function will attempt to reserve the passed range of + * minors and will return zero on success. + * + * Returns a -ve errno on failure. + */ +static struct char_device_struct * +__register_chrdev_region(unsigned int major, unsigned int baseminor, + int minorct, const char *name) +{ + struct char_device_struct *cd, **cp; + int ret = 0; + int i; + + cd = kzalloc(sizeof(struct char_device_struct), GFP_KERNEL); + if (cd == NULL) + return ERR_PTR(-ENOMEM); + + mutex_lock(&chrdevs_lock); + + /* temporary */ + if (major == 0) { + for (i = ARRAY_SIZE(chrdevs)-1; i > 0; i--) { + if (chrdevs[i] == NULL) + break; + } + + if (i == 0) { + ret = -EBUSY; + goto out; + } + major = i; + ret = major; + } + + cd->major = major; + cd->baseminor = baseminor; + cd->minorct = minorct; + strlcpy(cd->name, name, sizeof(cd->name)); + + i = major_to_index(major); + + for (cp = &chrdevs[i]; *cp; cp = &(*cp)->next) + if ((*cp)->major > major || + ((*cp)->major == major && + (((*cp)->baseminor >= baseminor) || + ((*cp)->baseminor + (*cp)->minorct > baseminor)))) + break; + + /* Check for overlapping minor ranges. */ + if (*cp && (*cp)->major == major) { + int old_min = (*cp)->baseminor; + int old_max = (*cp)->baseminor + (*cp)->minorct - 1; + int new_min = baseminor; + int new_max = baseminor + minorct - 1; + + /* New driver overlaps from the left. */ + if (new_max >= old_min && new_max <= old_max) { + ret = -EBUSY; + goto out; + } + + /* New driver overlaps from the right. */ + if (new_min <= old_max && new_min >= old_min) { + ret = -EBUSY; + goto out; + } + } + + cd->next = *cp; + *cp = cd; + mutex_unlock(&chrdevs_lock); + return cd; +out: + mutex_unlock(&chrdevs_lock); + kfree(cd); + return ERR_PTR(ret); +} + +static struct char_device_struct * +__unregister_chrdev_region(unsigned major, unsigned baseminor, int minorct) +{ + struct char_device_struct *cd = NULL, **cp; + int i = major_to_index(major); + + mutex_lock(&chrdevs_lock); + for (cp = &chrdevs[i]; *cp; cp = &(*cp)->next) + if ((*cp)->major == major && + (*cp)->baseminor == baseminor && + (*cp)->minorct == minorct) + break; + if (*cp) { + cd = *cp; + *cp = cd->next; + } + mutex_unlock(&chrdevs_lock); + return cd; +} + +/** + * register_chrdev_region() - register a range of device numbers + * @from: the first in the desired range of device numbers; must include + * the major number. + * @count: the number of consecutive device numbers required + * @name: the name of the device or driver. + * + * Return value is zero on success, a negative error code on failure. + */ +int register_chrdev_region(dev_t from, unsigned count, const char *name) +{ + struct char_device_struct *cd; + dev_t to = from + count; + dev_t n, next; + + for (n = from; n < to; n = next) { + next = MKDEV(MAJOR(n)+1, 0); + if (next > to) + next = to; + cd = __register_chrdev_region(MAJOR(n), MINOR(n), + next - n, name); + if (IS_ERR(cd)) + goto fail; + } + return 0; +fail: + to = n; + for (n = from; n < to; n = next) { + next = MKDEV(MAJOR(n)+1, 0); + kfree(__unregister_chrdev_region(MAJOR(n), MINOR(n), next - n)); + } + return PTR_ERR(cd); +} + +/** + * alloc_chrdev_region() - register a range of char device numbers + * @dev: output parameter for first assigned number + * @baseminor: first of the requested range of minor numbers + * @count: the number of minor numbers required + * @name: the name of the associated device or driver + * + * Allocates a range of char device numbers. The major number will be + * chosen dynamically, and returned (along with the first minor number) + * in @dev. Returns zero or a negative error code. + */ +int alloc_chrdev_region(dev_t *dev, unsigned baseminor, unsigned count, + const char *name) +{ + struct char_device_struct *cd; + cd = __register_chrdev_region(0, baseminor, count, name); + if (IS_ERR(cd)) + return PTR_ERR(cd); + *dev = MKDEV(cd->major, cd->baseminor); + return 0; +} + +/** + * register_chrdev() - Register a major number for character devices. + * @major: major device number or 0 for dynamic allocation + * @name: name of this range of devices + * @fops: file operations associated with this devices + * + * If @major == 0 this functions will dynamically allocate a major and return + * its number. + * + * If @major > 0 this function will attempt to reserve a device with the given + * major number and will return zero on success. + * + * Returns a -ve errno on failure. + * + * The name of this device has nothing to do with the name of the device in + * /dev. It only helps to keep track of the different owners of devices. If + * your module name has only one type of devices it's ok to use e.g. the name + * of the module here. + * + * This function registers a range of 256 minor numbers. The first minor number + * is 0. + */ +int register_chrdev(unsigned int major, const char *name, + const struct file_operations *fops) +{ + struct char_device_struct *cd; + struct cdev *cdev; + char *s; + int err = -ENOMEM; + + cd = __register_chrdev_region(major, 0, 256, name); + if (IS_ERR(cd)) + return PTR_ERR(cd); + + cdev = cdev_alloc(); + if (!cdev) + goto out2; + + cdev->owner = fops->owner; + cdev->ops = fops; + kobject_set_name(&cdev->kobj, "%s", name); + for (s = strchr(kobject_name(&cdev->kobj),'/'); s; s = strchr(s, '/')) + *s = '!'; + + err = cdev_add(cdev, MKDEV(cd->major, 0), 256); + if (err) + goto out; + + cd->cdev = cdev; + + return major ? 0 : cd->major; +out: + kobject_put(&cdev->kobj); +out2: + kfree(__unregister_chrdev_region(cd->major, 0, 256)); + return err; +} + +/** + * unregister_chrdev_region() - return a range of device numbers + * @from: the first in the range of numbers to unregister + * @count: the number of device numbers to unregister + * + * This function will unregister a range of @count device numbers, + * starting with @from. The caller should normally be the one who + * allocated those numbers in the first place... + */ +void unregister_chrdev_region(dev_t from, unsigned count) +{ + dev_t to = from + count; + dev_t n, next; + + for (n = from; n < to; n = next) { + next = MKDEV(MAJOR(n)+1, 0); + if (next > to) + next = to; + kfree(__unregister_chrdev_region(MAJOR(n), MINOR(n), next - n)); + } +} + +void unregister_chrdev(unsigned int major, const char *name) +{ + struct char_device_struct *cd; + cd = __unregister_chrdev_region(major, 0, 256); + if (cd && cd->cdev) + cdev_del(cd->cdev); + kfree(cd); +} + +static DEFINE_SPINLOCK(cdev_lock); + +static struct kobject *cdev_get(struct cdev *p) +{ + struct module *owner = p->owner; + struct kobject *kobj; + + if (owner && !try_module_get(owner)) + return NULL; + kobj = kobject_get(&p->kobj); + if (!kobj) + module_put(owner); + return kobj; +} + +void cdev_put(struct cdev *p) +{ + if (p) { + struct module *owner = p->owner; + kobject_put(&p->kobj); + module_put(owner); + } +} + +/* + * Called every time a character special file is opened + */ +static int chrdev_open(struct inode *inode, struct file *filp) +{ + struct cdev *p; + struct cdev *new = NULL; + int ret = 0; + + spin_lock(&cdev_lock); + p = inode->i_cdev; + if (!p) { + struct kobject *kobj; + int idx; + spin_unlock(&cdev_lock); + kobj = kobj_lookup(cdev_map, inode->i_rdev, &idx); + if (!kobj) + return -ENXIO; + new = container_of(kobj, struct cdev, kobj); + spin_lock(&cdev_lock); + /* Check i_cdev again in case somebody beat us to it while + we dropped the lock. */ + p = inode->i_cdev; + if (!p) { + inode->i_cdev = p = new; + inode->i_cindex = idx; + list_add(&inode->i_devices, &p->list); + new = NULL; + } else if (!cdev_get(p)) + ret = -ENXIO; + } else if (!cdev_get(p)) + ret = -ENXIO; + spin_unlock(&cdev_lock); + cdev_put(new); + if (ret) + return ret; + + ret = -ENXIO; + filp->f_op = fops_get(p->ops); + if (!filp->f_op) + goto out_cdev_put; + + if (filp->f_op->open) { + ret = filp->f_op->open(inode,filp); + if (ret) + goto out_cdev_put; + } + + return 0; + + out_cdev_put: + cdev_put(p); + return ret; +} + +void cd_forget(struct inode *inode) +{ + spin_lock(&cdev_lock); + list_del_init(&inode->i_devices); + inode->i_cdev = NULL; + spin_unlock(&cdev_lock); +} + +static void cdev_purge(struct cdev *cdev) +{ + spin_lock(&cdev_lock); + while (!list_empty(&cdev->list)) { + struct inode *inode; + inode = container_of(cdev->list.next, struct inode, i_devices); + list_del_init(&inode->i_devices); + inode->i_cdev = NULL; + } + spin_unlock(&cdev_lock); +} + +/* + * Dummy default file-operations: the only thing this does + * is contain the open that then fills in the correct operations + * depending on the special file... + */ +const struct file_operations def_chr_fops = { + .open = chrdev_open, +}; + +static struct kobject *exact_match(dev_t dev, int *part, void *data) +{ + struct cdev *p = data; + return &p->kobj; +} + +static int exact_lock(dev_t dev, void *data) +{ + struct cdev *p = data; + return cdev_get(p) ? 0 : -1; +} + +/** + * cdev_add() - add a char device to the system + * @p: the cdev structure for the device + * @dev: the first device number for which this device is responsible + * @count: the number of consecutive minor numbers corresponding to this + * device + * + * cdev_add() adds the device represented by @p to the system, making it + * live immediately. A negative error code is returned on failure. + */ +int cdev_add(struct cdev *p, dev_t dev, unsigned count) +{ + p->dev = dev; + p->count = count; + return kobj_map(cdev_map, dev, count, NULL, exact_match, exact_lock, p); +} + +static void cdev_unmap(dev_t dev, unsigned count) +{ + kobj_unmap(cdev_map, dev, count); +} + +/** + * cdev_del() - remove a cdev from the system + * @p: the cdev structure to be removed + * + * cdev_del() removes @p from the system, possibly freeing the structure + * itself. + */ +void cdev_del(struct cdev *p) +{ + cdev_unmap(p->dev, p->count); + kobject_put(&p->kobj); +} + + +static void cdev_default_release(struct kobject *kobj) +{ + struct cdev *p = container_of(kobj, struct cdev, kobj); + cdev_purge(p); +} + +static void cdev_dynamic_release(struct kobject *kobj) +{ + struct cdev *p = container_of(kobj, struct cdev, kobj); + cdev_purge(p); + kfree(p); +} + +static struct kobj_type ktype_cdev_default = { + .release = cdev_default_release, +}; + +static struct kobj_type ktype_cdev_dynamic = { + .release = cdev_dynamic_release, +}; + +/** + * cdev_alloc() - allocate a cdev structure + * + * Allocates and returns a cdev structure, or NULL on failure. + */ +struct cdev *cdev_alloc(void) +{ + struct cdev *p = kzalloc(sizeof(struct cdev), GFP_KERNEL); + if (p) { + INIT_LIST_HEAD(&p->list); + kobject_init(&p->kobj, &ktype_cdev_dynamic); + } + return p; +} + +/** + * cdev_init() - initialize a cdev structure + * @cdev: the structure to initialize + * @fops: the file_operations for this device + * + * Initializes @cdev, remembering @fops, making it ready to add to the + * system with cdev_add(). + */ +void cdev_init(struct cdev *cdev, const struct file_operations *fops) +{ + memset(cdev, 0, sizeof *cdev); + INIT_LIST_HEAD(&cdev->list); + kobject_init(&cdev->kobj, &ktype_cdev_default); + cdev->ops = fops; +} + +static struct kobject *base_probe(dev_t dev, int *part, void *data) +{ + if (request_module("char-major-%d-%d", MAJOR(dev), MINOR(dev)) > 0) + /* Make old-style 2.4 aliases work */ + request_module("char-major-%d", MAJOR(dev)); + return NULL; +} + +void __init chrdev_init(void) +{ + cdev_map = kobj_map_init(base_probe, &chrdevs_lock); + bdi_init(&directly_mappable_cdev_bdi); +} + +#ifndef LIBINPUT +core_initcall(chrdev_init); +#endif + +/* Let modules do char dev stuff */ +EXPORT_SYMBOL(register_chrdev_region); +EXPORT_SYMBOL(unregister_chrdev_region); +EXPORT_SYMBOL(alloc_chrdev_region); +EXPORT_SYMBOL(cdev_init); +EXPORT_SYMBOL(cdev_alloc); +EXPORT_SYMBOL(cdev_del); +EXPORT_SYMBOL(cdev_add); +EXPORT_SYMBOL(register_chrdev); +EXPORT_SYMBOL(unregister_chrdev); +EXPORT_SYMBOL(directly_mappable_cdev_bdi); |