From 26346ff681cb42c1436ed09c44dcae4809470dab Mon Sep 17 00:00:00 2001 From: "Aneesh Kumar K.V" Date: Sun, 10 Feb 2008 01:10:04 -0500 Subject: [PATCH] ext4: Don't panic in case of corrupt bitmap 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 Signed-off-by: Mingming Cao Signed-off-by: "Theodore Ts'o" --- fs/ext4/mballoc.c | 35 +++++++++++++++++++++-------------- 1 file changed, 21 insertions(+), 14 deletions(-) diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c index 5e3c3519141..dd0fcfcb35c 100644 --- a/fs/ext4/mballoc.c +++ b/fs/ext4/mballoc.c @@ -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; -- 2.41.1