[PATCH AUTOSEL 5.6 34/38] ext4: convert BUG_ON's to WARN_ON's in mballoc.c

Sasha Levin
2020-04-24T12:31:29Z

From: Theodore Ts'o <tytso@mit.edu>

[ Upstream commit 907ea529fc4c3296701d2bfc8b831dd2a8121a34 ]

If the in-core buddy bitmap gets corrupted (or out of sync with the
block bitmap), issue a WARN_ON and try to recover. In most cases this
involves skipping trying to allocate out of a particular block group.
We can end up declaring the file system corrupted, which is fair,
since the file system probably should be checked before we proceed any
further.

Link: https://lore.kernel.org/r/20200414035649.293164-1-tytso@mit.edu
Google-Bug-Id: 34811296
Google-Bug-Id: 34639169
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
fs/ext4/mballoc.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index 51a78eb65f3cf..2f7aebee1a7b4 100644
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -1936,7 +1936,8 @@ void ext4_mb_complex_scan_group(struct ext4_allocation_context *ac,
int free;

free = e4b->bd_info->bb_free;
- BUG_ON(free <= 0);
+ if (WARN_ON(free <= 0))
+ return;

i = e4b->bd_info->bb_first_free;

@@ -1959,7 +1960,8 @@ void ext4_mb_complex_scan_group(struct ext4_allocation_context *ac,
}

mb_find_extent(e4b, i, ac->ac_g_ex.fe_len, &ex);
- BUG_ON(ex.fe_len <= 0);
+ if (WARN_ON(ex.fe_len <= 0))
+ break;
if (free < ex.fe_len) {
ext4_grp_locked_error(sb, e4b->bd_group, 0, 0,
"%d free clusters as per "
--
2.20.1