From: Brian Foster <[email protected]>
If we hit a condition where we have allocated metadata blocks that
were not appropriately reserved, we risk underflow of
ei->i_reserved_meta_blocks. In turn, this can throw
sbi->s_dirtyclusters_counter significantly out of whack and undermine
the nondelalloc fallback logic in ext4_nonda_switch(). Warn if this
occurs and fix up the counter to handle only what we've reserved.
This condition is reproduced by xfstests 270 against ext2 with
delalloc enabled.
Signed-off-by: Brian Foster <[email protected]>
---
fs/ext4/inode.c | 9 +++++++++
1 files changed, 9 insertions(+), 0 deletions(-)
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index c77b0bd..b58845c 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -279,6 +279,15 @@ void ext4_da_update_reserve_space(struct inode *inode,
used = ei->i_reserved_data_blocks;
}
+ if (unlikely(ei->i_allocated_meta_blocks > ei->i_reserved_meta_blocks)) {
+ ext4_msg(inode->i_sb, KERN_NOTICE, "%s: ino %lu, allocated %d "
+ "with only %d reserved metadata blocks\n", __func__,
+ inode->i_ino, ei->i_allocated_meta_blocks,
+ ei->i_reserved_meta_blocks);
+ WARN_ON(1);
+ ei->i_allocated_meta_blocks = ei->i_reserved_meta_blocks;
+ }
+
/* Update per-inode reservations */
ei->i_reserved_data_blocks -= used;
ei->i_reserved_meta_blocks -= ei->i_allocated_meta_blocks;
--
1.7.7.6
On Mon, Apr 02, 2012 at 11:14:13AM -0400, Brian Foster wrote:
> From: Brian Foster <[email protected]>
>
> If we hit a condition where we have allocated metadata blocks that
> were not appropriately reserved, we risk underflow of
> ei->i_reserved_meta_blocks. In turn, this can throw
> sbi->s_dirtyclusters_counter significantly out of whack and undermine
> the nondelalloc fallback logic in ext4_nonda_switch(). Warn if this
> occurs and fix up the counter to handle only what we've reserved.
> This condition is reproduced by xfstests 270 against ext2 with
> delalloc enabled.
>
> Signed-off-by: Brian Foster <[email protected]>
Hi Brian,
Thanks for looking into this xfstests failure and proposing a bug fix.
My apologies for not getting back to you until now.
I modified your commit description a little, but the patch looks good
to me.
- Ted
Author: Brian Foster <[email protected]>
Date: Sun Jul 22 23:59:40 2012 -0400
ext4: don't let i_reserved_meta_blocks go negative
If we hit a condition where we have allocated metadata blocks that
were not appropriately reserved, we risk underflow of
ei->i_reserved_meta_blocks. In turn, this can throw
sbi->s_dirtyclusters_counter significantly out of whack and undermine
the nondelalloc fallback logic in ext4_nonda_switch(). Warn if this
occurs and set i_allocated_meta_blocks to avoid this problem.
This condition is reproduced by xfstests 270 against ext2 with
delalloc enabled:
Mar 28 08:58:02 localhost kernel: [ 171.526344] EXT4-fs (loop1): delayed blo
Mar 28 08:58:02 localhost kernel: [ 171.526346] EXT4-fs (loop1): This should
270 ultimately fails with an inconsistent filesystem and requires an
fsck to repair. The cause of the error is an underflow in
ext4_da_update_reserve_space() due to an unreserved meta block
allocation.
Signed-off-by: Brian Foster <[email protected]>
Signed-off-by: "Theodore Ts'o" <[email protected]>
Cc: [email protected]