On Sun, Jun 14, 2015 at 08:39:21AM +1000, Dave Chinner wrote: > On Sat, Jun 13, 2015 at 01:02:51AM +0000, Tom Christensen wrote: > > We've run into a bit of an issue with xfs running Ceph. The following bug details what we are seeing: > > https://bugs.launchpad.net/ubuntu/+source/xfs/+bug/1464308 > > > > Basically the Ceph OSD process gets hung in dstate due to the traceback in the bug. > > > > Here is additional info gathered: > > > > xfs bmap output for a random directory > > https://gist.github.com/dmmatson/e864252c7ff346df954a > > > > attr -l of the file dchinner indicated from the xfs bmap output > > (attr -l) > > (6:11:41 PM) dmatson: Attribute "cephos.spill_out" has a 2 byte value for rbd\udata.66039648e29a80.0000000000000d35__head_23EA10B8__5 > > (6:11:45 PM) dmatson: Attribute "ceph.snapset@3" has a 263 byte value for rbd\udata.66039648e29a80.0000000000000d35__head_23EA10B8__5 > > (6:11:49 PM) dmatson: Attribute "ceph.snapset@2" has a 1131 byte value for rbd\udata.66039648e29a80.0000000000000d35__head_23EA10B8__5 > > (6:11:53 PM) dmatson: Attribute "ceph.snapset@1" has a 2048 byte value for rbd\udata.66039648e29a80.0000000000000d35__head_23EA10B8__5 > > (6:11:56 PM) dmatson: Attribute "ceph._" has a 259 byte value for rbd\udata.66039648e29a80.0000000000000d35__head_23EA10B8__5 > > (6:12:00 PM) dmatson: Attribute "ceph.snapset" has a 2048 byte value for rbd\udata.66039648e29a80.0000000000000d35__head_23EA10B8__5 > > > > xfs_bmap -vp of same file > > > > rbd\udata.66039648e29a80.0000000000000d35__head_23EA10B8__5: > > (6:13:21 PM) dmatson: EXT: FILE-OFFSET BLOCK-RANGE AG AG-OFFSET TOTAL FLAGS > > (6:13:25 PM) dmatson: 0: [0..8191]: 2944471376..2944479567 16 (24445776..24453967) 8192 00000 > > And the attribute fork was: > > rbd\udata.66039648e29a80.0000000000000d35__head_23EA10B8__5: > EXT: FILE-OFFSET BLOCK-RANGE AG AG-OFFSET TOTAL FLAGS > 0: [0..7]: 1461176488..1461176495 8 (1163688..1163695) 8 00000 > 1: [8..31]: 1461176504..1461176527 8 (1163704..1163727) 24 00000 > > I just created a filesystem and attribute list identical to the > above, and came up with a attribute fork that looks like: > > /mnt/scratch/udata.66039648e29a80.0000000000000d35__head_23EA10B8__5: > EXT: FILE-OFFSET BLOCK-RANGE AG AG-OFFSET TOTAL FLAGS > 0: [0..7]: 120..127 0 (120..127) 8 00000 > 1: [8..15]: 112..119 0 (112..119) 8 00000 > 2: [16..23]: 104..111 0 (104..111) 8 00000 > > IOWs, there's an extra block in the attribute fork that is causing > problems than there needs to be. That tends to imply attribute > overwrites might be contributing here (the 3-phase overwrite > algorithm increases the space usage) so I'm going to need to try a > few different things to see if I can get an attribute fork into the > same shape.... I've had a test running overnight that generates attribute forks of this shape, but I haven't seen any problems. sequential grow of attributes, semi random growth, semi random truncation, etc don't seem to trip over this problem on a 4.1-rc6 kernel. Hence I'm going to need a metadump image of a filesystem with a broken file in it. An obfuscated dump is fine; I only need to look at the structure of the bad attribute fork. If you want to send the link privately to me that is fine, too. Cheers, Dave. -- Dave Chinner david@xxxxxxxxxxxxx _______________________________________________ xfs mailing list xfs@xxxxxxxxxxx http://oss.sgi.com/mailman/listinfo/xfs
