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/* Fetching and storing the hypermetadata (superblock and bg summary info).
Copyright (C) 1994, 1995 Free Software Foundation, Inc.
This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License as
published by the Free Software Foundation; either version 2, or (at
your option) any later version.
This program is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */
#include <string.h>
#include <stdio.h>
#include "ext2fs.h"
void
get_hypermetadata (void)
{
sblock = malloc (SBLOCK_SIZE);
assert (!diskfs_catch_exception ());
bcopy (disk_image + SBLOCK_OFFS, sblock, SBLOCK_SIZE);
diskfs_end_catch_exception ();
if (sblock->s_magic != EXT2_SUPER_MAGIC
#ifdef EXT2FS_PRE_02B_COMPAT
&& sblock->s_magic != EXT2_PRE_02B_MAGIC
#endif
)
ext2_panic("get_hypermetadata",
"Bad magic number %#x (should be %#x)",
sblock->s_magic, EXT2_SUPER_MAGIC);
block_size = EXT2_MIN_BLOCK_SIZE << sblock->s_log_block_size;
if (block_size > 8192)
ext2_panic("get_hypermetadata",
"Block size %ld is too big (max is 8192 bytes)", block_size);
if (block_size < SBLOCK_SIZE)
ext2_panic ("get_hypermetadata",
"Block size %ld is too small (min is %ld bytes)",
block_size, SBLOCK_SIZE);
assert ((vm_page_size % DEV_BSIZE) == 0);
assert ((block_size % DEV_BSIZE) == 0);
if (block_size < vm_page_size)
ext2_panic ("get_hypermetadata",
"Block size (%d) isn't a multiple of page size (%ld)",
block_size, vm_page_size);
/* Set these handy variables. */
inodes_per_block = block_size / sizeof (struct ext2_inode);
frag_size = EXT2_MIN_FRAG_SIZE << sblock->s_log_frag_size;
if (frag_size)
frags_per_block = block_size / frag_size;
else
ext2_panic("get_hypermetadata", "Frag size is zero!");
groups_count =
((sblock->s_blocks_count - sblock->s_first_data_block +
sblock->s_blocks_per_group - 1)
/ sblock->s_blocks_per_group);
itb_per_group = sblock->s_inodes_per_group / inodes_per_block;
desc_per_block = block_size / sizeof (struct ext2_group_desc);
addr_per_block = block_size / sizeof (u32);
db_per_group = (groups_count + desc_per_block - 1) / desc_per_block;
}
/* Write the csum data. This isn't backed by a pager because it is
taken from ordinary data blocks and might not be an even number
of pages; in that case writing it through the pager would nuke whatever
pages came after it on the disk and were backed by file pagers. */
void
diskfs_set_hypermetadata (int wait, int clean)
{
#if 0
vm_address_t buf;
vm_size_t bufsize;
error_t err;
spin_lock (&alloclock);
if (!csum_dirty)
{
spin_unlock (&alloclock);
return;
}
/* Copy into a page-aligned buffer to avoid bugs in kernel device code. */
bufsize = round_page (fragroundup (sblock, sblock->fs_cssize));
err = dev_read_sync (fsbtodb (sblock, sblock->fs_csaddr), &buf, bufsize);
if (!err)
{
bcopy (csum, (void *) buf, sblock->fs_cssize);
dev_write_sync (fsbtodb (sblock, sblock->fs_csaddr), buf, bufsize);
csum_dirty = 0;
vm_deallocate (mach_task_self (), buf, bufsize);
}
spin_unlock (&alloclock);
#endif
}
/* Copy the sblock into the disk */
void
copy_sblock ()
{
int clean = 1; /* XXX wrong... */
assert (!diskfs_catch_exception ());
spin_lock (&sblock_lock);
if (clean && !diskfs_readonly)
{
sblock->s_state |= EXT2_VALID_FS;
sblock_dirty = 1;
}
if (sblock_dirty)
{
bcopy (sblock, disk_image + SBLOCK_OFFS, SBLOCK_SIZE);
pokel_add (&sblock_pokel, disk_image + SBLOCK_OFFS, SBLOCK_SIZE);
sblock_dirty = 0;
}
if (clean && !diskfs_readonly)
{
sblock->s_state &= ~EXT2_VALID_FS;
sblock_dirty = 1;
}
spin_unlock (&sblock_lock);
diskfs_end_catch_exception ();
}
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