On Tue, Apr 17, 2012 at 09:54:32AM +1000, Dave Chinner wrote: > 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. > > ..... ..... > So, what are the flusher threads doing - where are they stuck? I have an answer of sorts: 90580.054767] task PC stack pid father [90580.056035] flush-253:16 D 0000000000000001 4136 32084 2 0x00000000 [90580.056035] ffff880004c558a0 0000000000000046 ffff880068b6cd48 ffff880004c55cb0 [90580.056035] ffff88007b616280 ffff880004c55fd8 ffff880004c55fd8 ffff880004c55fd8 [90580.056035] ffff88000681e340 ffff88007b616280 ffff880004c558b0 ffff88007981e000 [90580.056035] Call Trace: [90580.056035] [<ffffffff81afcd19>] schedule+0x29/0x70 [90580.056035] [<ffffffff814801fd>] xfs_trans_alloc+0x5d/0xb0 [90580.056035] [<ffffffff81099eb0>] ? add_wait_queue+0x60/0x60 [90580.056035] [<ffffffff81416b14>] xfs_setfilesize_trans_alloc+0x34/0xb0 [90580.056035] [<ffffffff814186f5>] xfs_vm_writepage+0x4a5/0x560 [90580.056035] [<ffffffff81127507>] __writepage+0x17/0x40 [90580.056035] [<ffffffff81127b3d>] write_cache_pages+0x20d/0x460 [90580.056035] [<ffffffff811274f0>] ? set_page_dirty_lock+0x60/0x60 [90580.056035] [<ffffffff81127dda>] generic_writepages+0x4a/0x70 [90580.056035] [<ffffffff814167ec>] xfs_vm_writepages+0x4c/0x60 [90580.056035] [<ffffffff81129711>] do_writepages+0x21/0x40 [90580.056035] [<ffffffff8118ee42>] writeback_single_inode+0x112/0x380 [90580.056035] [<ffffffff8118f25e>] writeback_sb_inodes+0x1ae/0x270 [90580.056035] [<ffffffff8118f4c0>] wb_writeback+0xe0/0x320 [90580.056035] [<ffffffff8108724a>] ? try_to_del_timer_sync+0x8a/0x110 [90580.056035] [<ffffffff81190bc8>] wb_do_writeback+0xb8/0x1d0 [90580.056035] [<ffffffff81085f40>] ? usleep_range+0x50/0x50 [90580.056035] [<ffffffff81190d6b>] bdi_writeback_thread+0x8b/0x280 [90580.056035] [<ffffffff81190ce0>] ? wb_do_writeback+0x1d0/0x1d0 [90580.056035] [<ffffffff81099403>] kthread+0x93/0xa0 [90580.056035] [<ffffffff81b06f64>] kernel_thread_helper+0x4/0x10 [90580.056035] [<ffffffff81099370>] ? kthread_freezable_should_stop+0x70/0x70 [90580.056035] [<ffffffff81b06f60>] ? gs_change+0x13/0x13 A dirty inode has slipped through the freeze process, and the flusher thread is stuck trying to allocate a transaction for setting the file size. I can reproduce this fairly easily, so a a bit of tracing should tell me exactly what is going wrong.... Cheers, Dave. -- Dave Chinner david@xxxxxxxxxxxxx _______________________________________________ xfs mailing list xfs@xxxxxxxxxxx http://oss.sgi.com/mailman/listinfo/xfs
