On Mon, Apr 02, 2012 at 11:14:13AM -0400, Brian Foster wrote:
> From: Brian Foster <bfoster@xxxxxxxxxx>
>
> 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 <bfoster@xxxxxxxxxx>
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 <bfoster@xxxxxxxxxx>
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 <bfoster@xxxxxxxxxx>
Signed-off-by: "Theodore Ts'o" <tytso@xxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
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