Messages in this thread | | | Date | Fri, 5 Oct 2012 14:37:26 +0200 | From | Willy Tarreau <> | Subject | Re: [ 110/180] ext4: dont let i_reserved_meta_blocks go negative |
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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 <bfoster@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 ?
Willy
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