/*
* closefs.c --- close an ext2 filesystem
*
* Copyright (C) 1993, 1994, 1995, 1996 Theodore Ts'o.
*
* %Begin-Header%
* This file may be redistributed under the terms of the GNU Library
* General Public License, version 2.
* %End-Header%
*/
#include <stdio.h>
#if HAVE_UNISTD_H
#include <unistd.h>
#endif
#include <time.h>
#include <string.h>
#include "ext2_fs.h"
#include "ext2fsP.h"
static int test_root(int a, int b)
{
if (a == 0)
return 1;
while (1) {
if (a == 1)
return 1;
if (a % b)
return 0;
a = a / b;
}
}
int ext2fs_bg_has_super(ext2_filsys fs, int group_block)
{
if (!(fs->super->s_feature_ro_compat &
EXT2_FEATURE_RO_COMPAT_SPARSE_SUPER))
return 1;
if (test_root(group_block, 3) || (test_root(group_block, 5)) ||
test_root(group_block, 7))
return 1;
return 0;
}
/*
* This function returns the location of the superblock, block group
* descriptors for a given block group. It currently returns the
* number of free blocks assuming that inode table and allocation
* bitmaps will be in the group. This is not necessarily the case
* when the flex_bg feature is enabled, so callers should take care!
* It was only really intended for use by mke2fs, and even there it's
* not that useful. In the future, when we redo this function for
* 64-bit block numbers, we should probably return the number of
* blocks used by the super block and group descriptors instead.
*
* See also the comment for ext2fs_reserve_super_and_bgd()
*/
int ext2fs_super_and_bgd_loc(ext2_filsys fs,
dgrp_t group,
blk_t *ret_super_blk,
blk_t *ret_old_desc_blk,
blk_t *ret_new_desc_blk,
int *ret_meta_bg)
{
blk_t group_block, super_blk = 0, old_desc_blk = 0, new_desc_blk = 0;
unsigned int meta_bg, meta_bg_size;
blk_t numblocks, old_desc_blocks;
int has_super;
group_block = ext2fs_group_first_block(fs, group);
if (fs->super->s_feature_incompat & EXT2_FEATURE_INCOMPAT_META_BG)
old_desc_blocks = fs->super->s_first_meta_bg;
else
old_desc_blocks =
fs->desc_blocks + fs->super->s_reserved_gdt_blocks;
if (group == fs->group_desc_count-1) {
numblocks = (fs->super->s_blocks_count -
fs->super->s_first_data_block) %
fs->super->s_blocks_per_group;
if (!numblocks)
numblocks = fs->super->s_blocks_per_group;
} else
numblocks = fs->super->s_blocks_per_group;
has_super = ext2fs_bg_has_super(fs, group);
if (has_super) {
super_blk = group_block;
numblocks--;
}
meta_bg_size = EXT2_DESC_PER_BLOCK(fs->super);
meta_bg = group / meta_bg_size;
if (!(fs->super->s_feature_incompat & EXT2_FEATURE_INCOMPAT_META_BG) ||
(meta_bg < fs->super->s_first_meta_bg)) {
if (has_super) {
old_desc_blk = group_block + 1;
numblocks -= old_desc_blocks;
}
} else {
if (((group % meta_bg_size) == 0) ||
((group % meta_bg_size) == 1) ||
((group % meta_bg_size) == (meta_bg_size-1))) {
if (has_super)
has_super = 1;
new_desc_blk = group_block + has_super;
numblocks--;
}
}
numblocks -= 2 + fs->inode_blocks_per_group;
if (ret_super_blk)
*ret_super_blk = super_blk;
if (ret_old_desc_blk)
*ret_old_desc_blk = old_desc_blk;
if (ret_new_desc_blk)
*ret_new_desc_blk = new_desc_blk;
if (ret_meta_bg)
*ret_meta_bg = meta_bg;
return (numblocks);
}
/*
* This function forces out the primary superblock. We need to only
* write out those fields which we have changed, since if the
* filesystem is mounted, it may have changed some of the other
* fields.
*
* It takes as input a superblock which has already been byte swapped
* (if necessary).
*
*/
static errcode_t write_primary_superblock(ext2_filsys fs,
struct ext2_super_block *super)
{
__u16 *old_super, *new_super;
int check_idx, write_idx, size;
errcode_t retval;
if (!fs->io->manager->write_byte || !fs->orig_super) {
fallback:
io_channel_set_blksize(fs->io, SUPERBLOCK_OFFSET);
retval = io_channel_write_blk(fs->io, 1, -SUPERBLOCK_SIZE,
super);
io_channel_set_blksize(fs->io, fs->blocksize);
return retval;
}
old_super = (__u16 *) fs->orig_super;
new_super = (__u16 *) super;
for (check_idx = 0; check_idx < SUPERBLOCK_SIZE/2; check_idx++) {
if (old_super[check_idx] == new_super[check_idx])
continue;
write_idx = check_idx;
for (check_idx++; check_idx < SUPERBLOCK_SIZE/2; check_idx++)
if (old_super[check_idx] == new_super[check_idx])
break;
size = 2 * (check_idx - write_idx);
#if 0
printf("Writing %d bytes starting at %d\n",
size, write_idx*2);
#endif
retval = io_channel_write_byte(fs->io,
SUPERBLOCK_OFFSET + (2 * write_idx), size,
new_super + write_idx);
if (retval == EXT2_ET_UNIMPLEMENTED)
goto fallback;
if (retval)
return retval;
}
memcpy(fs->orig_super, super, SUPERBLOCK_SIZE);
return 0;
}
/*
* Updates the revision to EXT2_DYNAMIC_REV
*/
void ext2fs_update_dynamic_rev(ext2_filsys fs)
{
struct ext2_super_block *sb = fs->super;
if (sb->s_rev_level > EXT2_GOOD_OLD_REV)
return;
sb->s_rev_level = EXT2_DYNAMIC_REV;
sb->s_first_ino = EXT2_GOOD_OLD_FIRST_INO;
sb->s_inode_size = EXT2_GOOD_OLD_INODE_SIZE;
/* s_uuid is handled by e2fsck already */
/* other fields should be left alone */
}
static errcode_t write_backup_super(ext2_filsys fs, dgrp_t group,
blk_t group_block,
struct ext2_super_block *super_shadow)
{
dgrp_t sgrp = group;
if (sgrp > ((1 << 16) - 1))
sgrp = (1 << 16) - 1;
#ifdef WORDS_BIGENDIAN
super_shadow->s_block_group_nr = ext2fs_swab16(sgrp);
#else
fs->super->s_block_group_nr = sgrp;
#endif
return io_channel_write_blk(fs->io, group_block, -SUPERBLOCK_SIZE,
super_shadow);
}
errcode_t ext2fs_flush(ext2_filsys fs)
{
dgrp_t i;
errcode_t retval;
unsigned long fs_state;
__u32 feature_incompat;
struct ext2_super_block *super_shadow = 0;
struct ext2_group_desc *group_shadow = 0;
#ifdef WORDS_BIGENDIAN
struct ext2_group_desc *s, *t;
dgrp_t j;
#endif
char *group_ptr;
int old_desc_blocks;
EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
fs_state = fs->super->s_state;
feature_incompat = fs->super->s_feature_incompat;
fs->super->s_wtime = fs->now ? fs->now : time(NULL);
fs->super->s_block_group_nr = 0;
#ifdef WORDS_BIGENDIAN
retval = EXT2_ET_NO_MEMORY;
retval = ext2fs_get_mem(SUPERBLOCK_SIZE, &super_shadow);
if (retval)
goto errout;
retval = ext2fs_get_array(fs->desc_blocks, fs->blocksize,
&group_shadow);
if (retval)
goto errout;
memset(group_shadow, 0, (size_t) fs->blocksize *
fs->desc_blocks);
/* swap the group descriptors */
for (j=0, s=fs->group_desc, t=group_shadow;
j < fs->group_desc_count; j++, t++, s++) {
*t = *s;
ext2fs_swap_group_desc(t);
}
#else
super_shadow = fs->super;
group_shadow = fs->group_desc;
#endif
/*
* Set the state of the FS to be non-valid. (The state has
* already been backed up earlier, and will be restored after
* we write out the backup superblocks.)
*/
fs->super->s_state &= ~EXT2_VALID_FS;
fs->super->s_feature_incompat &= ~EXT3_FEATURE_INCOMPAT_RECOVER;
#ifdef WORDS_BIGENDIAN
*super_shadow = *fs->super;
ext2fs_swap_super(super_shadow);
#endif
/*
* If this is an external journal device, don't write out the
* block group descriptors or any of the backup superblocks
*/
if (fs->super->s_feature_incompat &
EXT3_FEATURE_INCOMPAT_JOURNAL_DEV)
goto write_primary_superblock_only;
/*
* Write out the master group descriptors, and the backup
* superblocks and group descriptors.
*/
group_ptr = (char *) group_shadow;
if (fs->super->s_feature_incompat & EXT2_FEATURE_INCOMPAT_META_BG)
old_desc_blocks = fs->super->s_first_meta_bg;
else
old_desc_blocks = fs->desc_blocks;
for (i = 0; i < fs->group_desc_count; i++) {
blk_t super_blk, old_desc_blk, new_desc_blk;
int meta_bg;
ext2fs_super_and_bgd_loc(fs, i, &super_blk, &old_desc_blk,
&new_desc_blk, &meta_bg);
if (!(fs->flags & EXT2_FLAG_MASTER_SB_ONLY) &&i && super_blk) {
retval = write_backup_super(fs, i, super_blk,
super_shadow);
if (retval)
goto errout;
}
if (fs->flags & EXT2_FLAG_SUPER_ONLY)
continue;
if ((old_desc_blk) &&
(!(fs->flags & EXT2_FLAG_MASTER_SB_ONLY) || (i == 0))) {
retval = io_channel_write_blk(fs->io,
old_desc_blk, old_desc_blocks, group_ptr);
if (retval)
goto errout;
}
if (new_desc_blk) {
retval = io_channel_write_blk(fs->io, new_desc_blk,
1, group_ptr + (meta_bg*fs->blocksize));
if (retval)
goto errout;
}
}
/*
* If the write_bitmaps() function is present, call it to
* flush the bitmaps. This is done this way so that a simple
* program that doesn't mess with the bitmaps doesn't need to
* drag in the bitmaps.c code.
*/
if (fs->write_bitmaps) {
retval = fs->write_bitmaps(fs);
if (retval)
goto errout;
}
write_primary_superblock_only:
/*
* Write out master superblock. This has to be done
* separately, since it is located at a fixed location
* (SUPERBLOCK_OFFSET). We flush all other pending changes
* out to disk first, just to avoid a race condition with an
* insy-tinsy window....
*/
fs->super->s_block_group_nr = 0;
fs->super->s_state = fs_state;
fs->super->s_feature_incompat = feature_incompat;
#ifdef WORDS_BIGENDIAN
*super_shadow = *fs->super;
ext2fs_swap_super(super_shadow);
#endif
retval = io_channel_flush(fs->io);
retval = write_primary_superblock(fs, super_shadow);
if (retval)
goto errout;
fs->flags &= ~EXT2_FLAG_DIRTY;
retval = io_channel_flush(fs->io);
errout:
fs->super->s_state = fs_state;
#ifdef WORDS_BIGENDIAN
if (super_shadow)
ext2fs_free_mem(&super_shadow);
if (group_shadow)
ext2fs_free_mem(&group_shadow);
#endif
return retval;
}
errcode_t ext2fs_close(ext2_filsys fs)
{
errcode_t retval;
int meta_blks;
io_stats stats = 0;
EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
if (fs->write_bitmaps) {
retval = fs->write_bitmaps(fs);
if (retval)
return retval;
}
if (fs->super->s_kbytes_written &&
fs->io->manager->get_stats)
fs->io->manager->get_stats(fs->io, &stats);
if (stats && stats->bytes_written && (fs->flags & EXT2_FLAG_RW)) {
fs->super->s_kbytes_written += stats->bytes_written >> 10;
meta_blks = fs->desc_blocks + 1;
if (!(fs->flags & EXT2_FLAG_SUPER_ONLY))
fs->super->s_kbytes_written += meta_blks /
(fs->blocksize / 1024);
if ((fs->flags & EXT2_FLAG_DIRTY) == 0)
fs->flags |= EXT2_FLAG_SUPER_ONLY | EXT2_FLAG_DIRTY;
}
if (fs->flags & EXT2_FLAG_DIRTY) {
retval = ext2fs_flush(fs);
if (retval)
return retval;
}
ext2fs_free(fs);
return 0;
}