On Mon, Apr 16, 2012 at 08:47:00AM -0500, Mark Tinguely wrote: > On 03/27/12 11:44, Christoph Hellwig wrote: > >Now that we write back all metadata either synchronously or through the AIL > >we can simply implement metadata freezing in terms of emptying the AIL. > > > >The implementation for this is fairly simply and straight-forward: A new > >routine is added that increments a counter that tells xfsaild to not stop > >until the AIL is empty and then waits on a wakeup from > >xfs_trans_ail_delete_bulk to signal that the AIL is empty. > > > >As usual the devil is in the details, in this case the filesystem shutdown > >code. Currently we are a bit sloppy there and do not continue ail pushing > >in that case, and thus never reach the code in the log item implementations > >that can unwind in case of a shutdown filesystem. Also the code to > >abort inode and dquot flushes was rather sloppy before and did not remove > >the log items from the AIL, which had to be fixed as well. > > > >Also treat unmount the same way as freeze now, except that we still keep a > >synchronous inode reclaim pass to make sure we reclaim all clean inodes, too. > > > >As an upside we can now remove the radix tree based inode writeback and > >xfs_unmountfs_writesb. > > > >Signed-off-by: Christoph Hellwig<hch@xxxxxx> > > Sorry for the empty email. > > This series hangs my test boxes. This patch is the first indication > of the hang. Reboot, and remove patch 4 and the test are successful. > > The machine is still responsive. Only the SCRATCH filesystem from > the test suite is hung. > > Per Dave's observation, I added a couple inode reclaims to this > patch and the test gets further (hangs on run 9 of test 068 rather > than run 3). That implies that there are dirty inodes at the VFS level leaking through the freeze. ..... > The back traces are from a Linux 3.4-rc2 kernel with just patches > 0-4 of this series applied. This traceback does not have extra inode > reclaims. The hang is in test 068. I did an ls and sync to the > filesystem, so I included their tracebacks as well. live system. > > I have looked at the remaining patches in the series, but have not > reviewed them because they depend on this patch... > > --Mark. > --- > > crash> bt -f 20050 > PID: 20050 TASK: ffff88034a6943c0 CPU: 0 COMMAND: "fsstress" > #0 [ffff88034aa93d18] __schedule at ffffffff81416e50 > #1 [ffff88034aa93e60] schedule at ffffffff814171c4 > #2 [ffff88034aa93e70] do_wait at ffffffff81040e39 > #3 [ffff88034aa93ee0] sys_wait4 at ffffffff81040f11 > #4 [ffff88034aa93f80] system_call_fastpath at ffffffff8141fff9 > > PID: 20051 TASK: ffff88034e31e600 CPU: 3 COMMAND: "fsstress" > #0 [ffff88034c5c1c08] __schedule at ffffffff81416e50 > #1 [ffff88034c5c1d50] schedule at ffffffff814171c4 > #2 [ffff88034c5c1d60] xfs_file_aio_write at ffffffffa044d4b5 [xfs] > #3 [ffff88034c5c1df0] do_sync_write at ffffffff8114d3d9 > #4 [ffff88034c5c1f10] vfs_write at ffffffff8114da0b > #5 [ffff88034c5c1f40] sys_write at ffffffff8114db60 > #6 [ffff88034c5c1f80] system_call_fastpath at ffffffff8141fff9 Frozen write, not holding any locks. > PID: 20052 TASK: ffff88034ad56080 CPU: 3 COMMAND: "fsstress" > #0 [ffff88034a88fbb8] __schedule at ffffffff81416e50 > #1 [ffff88034a88fd00] schedule at ffffffff814171c4 > #2 [ffff88034a88fd10] schedule_timeout at ffffffff81415455 > #3 [ffff88034a88fdb0] wait_for_common at ffffffff814166b7 > #4 [ffff88034a88fe40] wait_for_completion at ffffffff81416828 > #5 [ffff88034a88fe50] sync_inodes_sb at ffffffff81174eaa > #6 [ffff88034a88fee0] __sync_filesystem at ffffffff8117a4a0 > #7 [ffff88034a88ff00] sync_one_sb at ffffffff8117a4c7 > #8 [ffff88034a88ff10] iterate_supers at ffffffff8115126b > #9 [ffff88034a88ff50] sys_sync at ffffffff8117a515 > #10 [ffff88034a88ff80] system_call_fastpath at ffffffff8141fff9 Waiting for flusher thread completion, holding the sb->s_umount lock in read mode. > PID: 20089 TASK: ffff88034c5ca340 CPU: 2 COMMAND: "xfs_freeze" > #0 [ffff88034aaafd18] __schedule at ffffffff81416e50 > #1 [ffff88034aaafe60] schedule at ffffffff814171c4 > #2 [ffff88034aaafe70] do_wait at ffffffff81040e39 > #3 [ffff88034aaafee0] sys_wait4 at ffffffff81040f11 > #4 [ffff88034aaaff80] system_call_fastpath at ffffffff8141fff9 > > PID: 20093 TASK: ffff88034b42a4c0 CPU: 1 COMMAND: "xfs_io" > #0 [ffff88034c3abc98] __schedule at ffffffff81416e50 > #1 [ffff88034c3abde0] schedule at ffffffff814171c4 > #2 [ffff88034c3abdf0] rwsem_down_failed_common at ffffffff81417de5 > #3 [ffff88034c3abe60] rwsem_down_write_failed at ffffffff81417e93 > #4 [ffff88034c3abe70] call_rwsem_down_write_failed at ffffffff8123fd93 > #5 [ffff88034c3abeb0] down_write at ffffffff81416110 > #6 [ffff88034c3abec0] thaw_super at ffffffff81150343 > #7 [ffff88034c3abef0] do_vfs_ioctl at ffffffff8115efb8 > #8 [ffff88034c3abf30] sys_ioctl at ffffffff8115f139 > #9 [ffff88034c3abf80] system_call_fastpath at ffffffff8141fff9 waiting for sb->s_umount, which can only be released by flusher thread completion. > PID: 20185 TASK: ffff88034c31c280 CPU: 1 COMMAND: "sync" > #0 [ffff88034afe7b88] __schedule at ffffffff81416e50 > #1 [ffff88034afe7cd0] schedule at ffffffff814171c4 > #2 [ffff88034afe7ce0] schedule_timeout at ffffffff81415455 > #3 [ffff88034afe7d80] wait_for_common at ffffffff814166b7 > #4 [ffff88034afe7e10] wait_for_completion at ffffffff81416828 > #5 [ffff88034afe7e20] writeback_inodes_sb_nr at ffffffff81174c69 > #6 [ffff88034afe7eb0] writeback_inodes_sb at ffffffff8117522c > #7 [ffff88034afe7ee0] __sync_filesystem at ffffffff8117a469 > #8 [ffff88034afe7f00] sync_one_sb at ffffffff8117a4c7 > #9 [ffff88034afe7f10] iterate_supers at ffffffff8115126b > #10 [ffff88034afe7f50] sys_sync at ffffffff8117a4ff > #11 [ffff88034afe7f80] system_call_fastpath at ffffffff8141fff9 waiting for flusher thread completion, holding the sb->s_umount lock in read mode. > > PID: 20110 TASK: ffff88034a4820c0 CPU: 2 COMMAND: "ls" > #0 [ffff88034a855c78] __schedule at ffffffff81416e50 > #1 [ffff88034a855dc0] schedule at ffffffff814171c4 > #2 [ffff88034a855dd0] xfs_trans_alloc at ffffffffa0499fb5 [xfs] > #3 [ffff88034a855e30] xfs_fs_dirty_inode at ffffffffa0457aa2 [xfs] > #4 [ffff88034a855e60] __mark_inode_dirty at ffffffff811753da > #5 [ffff88034a855ea0] touch_atime at ffffffff811662db > #6 [ffff88034a855ef0] vfs_readdir at ffffffff8115f934 > #7 [ffff88034a855f30] sys_getdents64 at ffffffff8115f9c3 > #8 [ffff88034a855f80] system_call_fastpath at ffffffff8141fff9 Frozen attribute modification, no locks held. So, what are the flusher threads doing - where are they stuck? Cheers, Dave. -- Dave Chinner david@xxxxxxxxxxxxx _______________________________________________ xfs mailing list xfs@xxxxxxxxxxx http://oss.sgi.com/mailman/listinfo/xfs
