On 10/05/2012 08:37 AM, Willy Tarreau wrote: > On Fri, Oct 05, 2012 at 07:59:11AM -0400, Brian Foster wrote: >> On 10/04/2012 05:55 PM, Ben Hutchings wrote: >>> On Tue, Oct 02, 2012 at 12:53:47AM +0200, Willy Tarreau wrote: >>>> 2.6.32-longterm review patch. If anyone has any objections, please let me >>>> know. >>>> >>>> ------------------ >>>> >>>> From: Brian Foster <bfos...@redhat.com> >>>> >>>> commit 97795d2a5b8d3c8dc4365d4bd3404191840453ba upstream. >>>> >>>> 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 >>>> block allocation failed for inode 14 at logical offset 64486 with max >>>> blocks 64 with error -28 >>>> Mar 28 08:58:02 localhost kernel: [ 171.526346] EXT4-fs (loop1): This >>>> should not happen!! Data will be lost >>>> >>>> 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. >>> [...] >>>> + 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; >>>> + } >>> [...] >>> >>> This seems to be working around a bug elsewhere. Has the underlying >>> bug been fixed in mainline yet? >>> >> >> Yes, the bug was fixed in: >> >> 03179fe92318e7934c180d96f12eff2cb36ef7b6 >> ext4: undo ext4_calc_metadata_amount if we fail to claim space > > So should we merge this one instead/too ? >
>From the perspective of the bug, I think you would want both patches. I should probably defer to Ted if he proposed this latter change for stable... Brian > Willy > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/