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| author | Theodore Ts'o <tytso@mit.edu> | 2014-07-30 22:17:17 -0400 |
|---|---|---|
| committer | Theodore Ts'o <tytso@mit.edu> | 2014-07-30 22:17:17 -0400 |
| commit | 86f0afd463215fc3e58020493482faa4ac3a4d69 (patch) | |
| tree | 977290d56ae0893d296a3b17e112cd0c65f9ab58 | |
| parent | ee98fa3a8b148a234600a20f7cdc2b4b37f38083 (diff) | |
| download | linux-86f0afd463215fc3e58020493482faa4ac3a4d69.tar.bz2 | |
ext4: fix ext4_discard_allocated_blocks() if we can't allocate the pa struct
If there is a failure while allocating the preallocation structure, a
number of blocks can end up getting marked in the in-memory buddy
bitmap, and then not getting released. This can result in the
following corruption getting reported by the kernel:
EXT4-fs error (device sda3): ext4_mb_generate_buddy:758: group 1126,
12793 clusters in bitmap, 12729 in gd
In that case, we need to release the blocks using mb_free_blocks().
Tested: fs smoke test; also demonstrated that with injected errors,
the file system is no longer getting corrupted
Google-Bug-Id: 16657874
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Cc: stable@vger.kernel.org
| -rw-r--r-- | fs/ext4/mballoc.c | 21 |
1 files changed, 20 insertions, 1 deletions
diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c index 0e9466f9e767..956027711faf 100644 --- a/fs/ext4/mballoc.c +++ b/fs/ext4/mballoc.c @@ -3217,8 +3217,27 @@ static void ext4_mb_collect_stats(struct ext4_allocation_context *ac) static void ext4_discard_allocated_blocks(struct ext4_allocation_context *ac) { struct ext4_prealloc_space *pa = ac->ac_pa; + struct ext4_buddy e4b; + int err; - if (pa && pa->pa_type == MB_INODE_PA) + if (pa == NULL) { + err = ext4_mb_load_buddy(ac->ac_sb, ac->ac_f_ex.fe_group, &e4b); + if (err) { + /* + * This should never happen since we pin the + * pages in the ext4_allocation_context so + * ext4_mb_load_buddy() should never fail. + */ + WARN(1, "mb_load_buddy failed (%d)", err); + return; + } + ext4_lock_group(ac->ac_sb, ac->ac_f_ex.fe_group); + mb_free_blocks(ac->ac_inode, &e4b, ac->ac_f_ex.fe_start, + ac->ac_f_ex.fe_len); + ext4_unlock_group(ac->ac_sb, ac->ac_f_ex.fe_group); + return; + } + if (pa->pa_type == MB_INODE_PA) pa->pa_free += ac->ac_b_ex.fe_len; } |