diff options
| -rw-r--r-- | ext2fs/hyper.c | 99 |
1 files changed, 72 insertions, 27 deletions
diff --git a/ext2fs/hyper.c b/ext2fs/hyper.c index f4e085ce..fa70888f 100644 --- a/ext2fs/hyper.c +++ b/ext2fs/hyper.c @@ -22,6 +22,36 @@ #include <stdio.h> #include "ext2fs.h" +vm_address_t zeroblock = 0; +char *modified_global_blocks = 0; + +static void allocate_mod_map () +{ + static vm_size_t mod_map_size = 0; + + if (modified_global_blocks && mod_map_size) + /* Get rid of the old one. */ + vm_deallocate (mach_task_self (), + (vm_address_t)modified_global_blocks, mod_map_size); + + if (!diskfs_readonly && block_size < vm_page_size) + /* If the block size is too small, we have to take extra care when + writing out pages from the global pager, to make sure we don't stomp + on any file pager blocks. In this case use a bitmap to record which + global blocks are actually modified so the pager can write only them. */ + { + error_t err; + /* One bit per filesystem block. */ + mod_map_size = sblock->s_blocks_count >> 3; + err = + vm_allocate (mach_task_self (), + (vm_address_t *)&modified_global_blocks, mod_map_size, 1); + assert_perror (err); + } + else + modified_global_blocks = 0; +} + error_t get_hypermetadata (void) { @@ -30,6 +60,9 @@ get_hypermetadata (void) if (err) return err; + if (zeroblock) + vm_deallocate (mach_task_self (), zeroblock, block_size); + sblock = (struct ext2_super_block *)boffs_ptr (SBLOCK_OFFS); if (sblock->s_magic != EXT2_SUPER_MAGIC @@ -45,13 +78,18 @@ get_hypermetadata (void) if (block_size > 8192) ext2_panic ("block size %ld is too big (max is 8192 bytes)", block_size); - log2_dev_blocks_per_fs_block = 0; - while ((device_block_size << log2_dev_blocks_per_fs_block) < block_size) - log2_dev_blocks_per_fs_block++; - if ((device_block_size << log2_dev_blocks_per_fs_block) != block_size) + log2_block_size = 0; + while ((1 << log2_block_size) < block_size) + log2_block_size++; + if ((1 << log2_block_size) != block_size) + ext2_panic ("block size %ld isn't a power of two!", block_size); + + log2_dev_blocks_per_fs_block = + log2_block_size - diskfs_log2_device_block_size; + if (log2_dev_blocks_per_fs_block < 0) ext2_panic ("block size %ld isn't a power-of-two multiple of the device" " block size (%d)!", - block_size, device_block_size); + block_size, diskfs_device_block_size); log2_stat_blocks_per_fs_block = 0; while ((512 << log2_stat_blocks_per_fs_block) < block_size) @@ -60,27 +98,7 @@ get_hypermetadata (void) ext2_panic ("block size %ld isn't a power-of-two multiple of 512!", block_size); - log2_block_size = 0; - while ((1 << log2_block_size) < block_size) - log2_block_size++; - if ((1 << log2_block_size) != block_size) - ext2_panic ("block size %ld isn't a power of two!", block_size); - - if (!diskfs_readonly && block_size < vm_page_size) - /* If the block size is too small, we have to take extra care when - writing out pages from the global pager, to make sure we don't stomp - on any file pager blocks. In this case use a bitmap to record which - global blocks are actually modified so the pager can write only them. */ - { - /* One bit per filesystem block. */ - err = - vm_allocate (mach_task_self (), - (vm_address_t *)&modified_global_blocks, - sblock->s_blocks_count >> 3, 1); - assert_perror (err); - } - else - modified_global_blocks = 0; + allocate_mod_map (); /* Set these handy variables. */ inodes_per_block = block_size / sizeof (struct ext2_inode); @@ -103,6 +121,15 @@ get_hypermetadata (void) diskfs_end_catch_exception (); + if (diskfs_device_size + < (sblock->s_blocks_count << log2_dev_blocks_per_fs_block)) + ext2_panic ("disk size (%ld blocks) too small (superblock says we need %ld)", + diskfs_device_size, + sblock->s_blocks_count << log2_dev_blocks_per_fs_block); + + /* A handy source of page-aligned zeros. */ + vm_allocate (mach_task_self (), &zeroblock, block_size, 1); + return 0; } @@ -117,9 +144,27 @@ diskfs_set_hypermetadata (int wait, int clean) sblock_dirty = 0; /* doesn't matter if this gets stomped */ bcopy (sblock, (void *)page_buf, SBLOCK_SIZE); ((struct ext2_super_block *)page_buf)->s_state |= EXT2_VALID_FS; - dev_write_sync (SBLOCK_OFFS / device_block_size, page_buf, block_size); + diskfs_device_write_sync (SBLOCK_OFFS >> diskfs_log2_device_block_size, + page_buf, block_size); free_page_buf (page_buf); } else if (sblock_dirty) sync_super_block (); } + +void +diskfs_readonly_changed (int readonly) +{ + allocate_mod_map (); + + vm_protect (mach_task_self (), + (vm_address_t)disk_image, + diskfs_device_size << diskfs_log2_device_block_size, + 0, VM_PROT_READ | (diskfs_readonly ? 0 : VM_PROT_WRITE)); + + if (!readonly && (sblock->s_state & EXT2_VALID_FS)) + { + sblock->s_state &= ~EXT2_VALID_FS; + sync_super_block (); + } +} |