On Thu, Dec 12, 2013 at 05:30:14PM +0800, Jeff Liu wrote:
> On 12/12 2013 13:34, Dave Chinner wrote:
> > From: Dave Chinner <dchinner@xxxxxxxxxx>
> > fsstress failed during a shutdown with the following assert:
> Looks fsstress is always a good aid to make file system cry... :-P
Heh. That it is. :)
> I wonder if here the shutdown is simulated via xfstests/src/godown or not,
> but I can trigger another hang up issue with this patch via a test case
> below(80% reproducible, I also ran the test against the left patches in
> this series, this problem still exists):
I occassionally get that hang, too. It's a "once a month" type hang,
and I've never beenable to reproduce it reliably enough to debug.
> mkfs.xfs -f /dev/sda7
> for ((i=0;i<10;i++))
> mount /dev/sda7 /xfs
> fsstress -d /xfs -n 1000 -p 100 >/dev/null 2>&1 &
> sleep 10
> godown /xfs
> killall -q fsstress
> umount /xfs
> It seems there is no such kind of test cases in xfstestes for now, I'd
> write one if required.
nothing quite that generic - xfs/087 does a loop like that over
different log configurations, but that's testing log recovery more
than shutdown sanity. Adding that test would be a good idea - it's a
shame no other filesystem supports a shutdown like XFS does....
> The backtraces were shown as following:
> [ 365.987493] INFO: task fsstress:3215 blocked for more than 120 seconds.
> [ 365.987499] Tainted: PF O 3.13.0-rc2+ #13
> [ 365.987500] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables
> this message.
> [ 365.987502] fsstress D ffff88026f254440 0 3215 3142
> [ 365.987507] ffff880253f19de0 0000000000000086 ffff880242071800
> [ 365.987512] 0000000000014440 0000000000014440 ffff880242071800
> [ 365.987515] ffff880073694c80 ffff880073694c90 ffffffffffffffff
> [ 365.987519] Call Trace:
> [ 365.987528] [<ffffffff81718779>] schedule+0x29/0x70
> [ 365.987560] [<ffffffffa0c2a49d>] xlog_cil_force_lsn+0x18d/0x1e0 [xfs]
> [ 365.987565] [<ffffffff81097210>] ? wake_up_state+0x20/0x20
> [ 365.987570] [<ffffffff811e8770>] ? do_fsync+0x80/0x80
> [ 365.987594] [<ffffffffa0c28921>] _xfs_log_force+0x61/0x270 [xfs]
> [ 365.987599] [<ffffffff812b0610>] ? jbd2_log_wait_commit+0x110/0x180
> [ 365.987603] [<ffffffff810a83f0>] ? prepare_to_wait_event+0x100/0x100
> [ 365.987607] [<ffffffff811e8770>] ? do_fsync+0x80/0x80
> [ 365.987629] [<ffffffffa0c28b56>] xfs_log_force+0x26/0x80 [xfs]
> [ 365.987648] [<ffffffffa0bcf35d>] xfs_fs_sync_fs+0x2d/0x50 [xfs]
> [ 365.987652] [<ffffffff811e8790>] sync_fs_one_sb+0x20/0x30
> [ 365.987656] [<ffffffff811bcc32>] iterate_supers+0xb2/0x110
> [ 365.987660] [<ffffffff811e88c2>] sys_sync+0x62/0xa0
> [ 365.987665] [<ffffffff81724ced>] system_call_fastpath+0x1a/0x1f
> [ 372.225302] XFS (sda7): xfs_log_force: error 5 returned.
> [ 402.275608] XFS (sda7): xfs_log_force: error 5 returned.
> [ 432.325929] XFS (sda7): xfs_log_force: error 5 returned.
> [ 462.376239] XFS (sda7): xfs_log_force: error 5 returned.
So what we see here is that there is a race condition somewhere in
the shutdown code. The shutdown is supposed to wake everyone waiting
of the ic_force_wait wait queue on each iclog, but for some reason
that hasn't happened. The sleepers check for XLOG_STATE_IOERROR
(which is set during the force shutdown before we wake ic_force_wait
sleepers) before they go to sleep, so whatever the race is it isn't
immediately obvious to me.