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ext4: Don't panic in case of corrupt bitmap

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Multiblock allocator calls BUG_ON in many case if the free and used
blocks count obtained looking at the bitmap is different from what
the allocator internally accounted for. Use ext4_error in such case
and don't panic the system.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Mingming Cao <cmm@us.ibm.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
This commit is contained in:
Aneesh Kumar K.V 2008-02-10 01:10:04 -05:00 committed by Theodore Ts'o
parent 256bdb497c
commit 26346ff681
1 changed files with 21 additions and 14 deletions
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35
fs/ext4/mballoc.c
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@ -681,7 +681,6 @@ static void *mb_find_buddy(struct ext4_buddy *e4b, int order, int *max)
{
char *bb;
/* FIXME!! is this needed */
BUG_ON(EXT4_MB_BITMAP(e4b) == EXT4_MB_BUDDY(e4b));
BUG_ON(max == NULL);
@ -965,7 +964,7 @@ static void ext4_mb_generate_buddy(struct super_block *sb,
grp->bb_fragments = fragments;
if (free != grp->bb_free) {
printk(KERN_DEBUG
ext4_error(sb, __FUNCTION__,
"EXT4-fs: group %lu: %u blocks in bitmap, %u in gd\n",
group, free, grp->bb_free);
grp->bb_free = free;
@ -1822,13 +1821,24 @@ static void ext4_mb_complex_scan_group(struct ext4_allocation_context *ac,
i = ext4_find_next_zero_bit(bitmap,
EXT4_BLOCKS_PER_GROUP(sb), i);
if (i >= EXT4_BLOCKS_PER_GROUP(sb)) {
BUG_ON(free != 0);
/*
* IF we corrupt the bitmap we won't find any
* free blocks even though group info says we
* we have free blocks
*/
ext4_error(sb, __FUNCTION__, "%d free blocks as per "
"group info. But bitmap says 0\n",
free);
break;
}
mb_find_extent(e4b, 0, i, ac->ac_g_ex.fe_len, &ex);
BUG_ON(ex.fe_len <= 0);
BUG_ON(free < ex.fe_len);
if (free < ex.fe_len) {
ext4_error(sb, __FUNCTION__, "%d free blocks as per "
"group info. But got %d blocks\n",
free, ex.fe_len);
}
ext4_mb_measure_extent(ac, &ex, e4b);
@ -3363,13 +3373,10 @@ static void ext4_mb_use_group_pa(struct ext4_allocation_context *ac,
ac->ac_pa = pa;
/* we don't correct pa_pstart or pa_plen here to avoid
* possible race when tte group is being loaded concurrently
* possible race when the group is being loaded concurrently
* instead we correct pa later, after blocks are marked
* in on-disk bitmap -- see ext4_mb_release_context() */
/*
* FIXME!! but the other CPUs can look at this particular
* pa and think that it have enought free blocks if we
* don't update pa_free here right ?
* in on-disk bitmap -- see ext4_mb_release_context()
* Other CPUs are prevented from allocating from this pa by lg_mutex
*/
mb_debug("use %u/%u from group pa %p\n", pa->pa_lstart-len, len, pa);
}
@ -3758,13 +3765,13 @@ static int ext4_mb_release_inode_pa(struct ext4_buddy *e4b,
bit = next + 1;
}
if (free != pa->pa_free) {
printk(KERN_ERR "pa %p: logic %lu, phys. %lu, len %lu\n",
printk(KERN_CRIT "pa %p: logic %lu, phys. %lu, len %lu\n",
pa, (unsigned long) pa->pa_lstart,
(unsigned long) pa->pa_pstart,
(unsigned long) pa->pa_len);
printk(KERN_ERR "free %u, pa_free %u\n", free, pa->pa_free);
ext4_error(sb, __FUNCTION__, "free %u, pa_free %u\n",
free, pa->pa_free);
}
BUG_ON(free != pa->pa_free);
atomic_add(free, &sbi->s_mb_discarded);
if (ac)
kmem_cache_free(ext4_ac_cachep, ac);
@ -4435,7 +4442,7 @@ void ext4_mb_free_blocks(handle_t *handle, struct inode *inode,
unsigned long block, unsigned long count,
int metadata, unsigned long *freed)
{
struct buffer_head *bitmap_bh = 0;
struct buffer_head *bitmap_bh = NULL;
struct super_block *sb = inode->i_sb;
struct ext4_allocation_context *ac = NULL;
struct ext4_group_desc *gdp;