From e56eb6590693a5a340e8f596db2768a6e1b9e236 Mon Sep 17 00:00:00 2001 From: "Aneesh Kumar K.V" Date: Fri, 15 Feb 2008 13:48:21 -0500 Subject: [PATCH] ext4: Don't claim block from group which has corrupt bitmap In ext4_mb_complex_scan_group, if the extent length of the newly found extentet is greater than than the total free blocks counted in group info, break without claiming the block. Document different ext4_error usage, explaining the state with which we continue if we mount with errors=continue Signed-off-by: Aneesh Kumar K.V Signed-off-by: Mingming Cao Signed-off-by: "Theodore Ts'o" --- fs/ext4/mballoc.c | 16 +++++++++++++++- 1 file changed, 15 insertions(+), 1 deletion(-) diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c index 2121184a3fa5..6968c53e62ad 100644 --- a/fs/ext4/mballoc.c +++ b/fs/ext4/mballoc.c @@ -967,6 +967,10 @@ static void ext4_mb_generate_buddy(struct super_block *sb, ext4_error(sb, __FUNCTION__, "EXT4-fs: group %lu: %u blocks in bitmap, %u in gd\n", group, free, grp->bb_free); + /* + * If we intent to continue, we consider group descritor + * corrupt and update bb_free using bitmap value + */ grp->bb_free = free; } @@ -1822,7 +1826,7 @@ static void ext4_mb_complex_scan_group(struct ext4_allocation_context *ac, EXT4_BLOCKS_PER_GROUP(sb), i); if (i >= EXT4_BLOCKS_PER_GROUP(sb)) { /* - * IF we corrupt the bitmap we won't find any + * IF we have corrupt bitmap, we won't find any * free blocks even though group info says we * we have free blocks */ @@ -1838,6 +1842,12 @@ static void ext4_mb_complex_scan_group(struct ext4_allocation_context *ac, ext4_error(sb, __FUNCTION__, "%d free blocks as per " "group info. But got %d blocks\n", free, ex.fe_len); + /* + * The number of free blocks differs. This mostly + * indicate that the bitmap is corrupt. So exit + * without claiming the space. + */ + break; } ext4_mb_measure_extent(ac, &ex, e4b); @@ -3771,6 +3781,10 @@ static int ext4_mb_release_inode_pa(struct ext4_buddy *e4b, (unsigned long) pa->pa_len); ext4_error(sb, __FUNCTION__, "free %u, pa_free %u\n", free, pa->pa_free); + /* + * pa is already deleted so we use the value obtained + * from the bitmap and continue. + */ } atomic_add(free, &sbi->s_mb_discarded); if (ac) -- 2.30.2