Messages in this thread | | | From | "Janos Haar" <> | Subject | Re: XFS related hang (was Re: How to send a break? - dump from frozen 64bit linux) | Date | Wed, 31 May 2006 10:00:33 +0200 |
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----- Original Message ----- From: "Nathan Scott" <nathans@sgi.com> To: "Janos Haar" <djani22@netcenter.hu> Cc: <linux-kernel@vger.kernel.org>; <linux-xfs@oss.sgi.com> Sent: Wednesday, May 31, 2006 6:38 AM Subject: XFS related hang (was Re: How to send a break? - dump from frozen 64bit linux)
> On Tue, May 30, 2006 at 09:20:31PM -0400, Steven Rostedt wrote: > > Added all those listed in the MAINTAINERS file for XFS. > > Thanks Steve. > > > On Tue, 2006-05-30 at 15:03 -0400, Valdis.Kletnieks@vt.edu wrote: > > > On Tue, 30 May 2006 12:22:01 +0200, Janos Haar said: > > > Half the processes on the box seem wedged at that same mutex_lock. I can't > > > seem to find an xfs_qm_shake in my source tree though. > > Its in fs/xfs/quota/xfs_qm.c. > > > kswapd0 D ffff81011fe03c38 0 297 1 1287 19 (L-TLB) > > ffff81011fe03c38 0000000000000004 000000000000000a ffff81011f92ba68 > > ffff81011f92b850 ffffffff805a23a0 0000149f99fa7d7c 000000000003bcde > > 000000002f2c46e0 ffff81008bc37180 > > Call Trace: <ffffffff804e5522>{schedule_timeout+34} > > <ffffffff80269f87>{xfs_qm_dqunpin_wait+220} <ffffffff80140e74>{debug_mutex_free_waiter+141} > > So, we're waiting here on a synchronisation variable that'll > be released once the dquot metadata buffer write completes. > > > So it is now waiting to be woken up by something that calls: > > > > xfs_qm_dquot_logitem_unpin which seems to be the function to wake it > > up. > > Mhmm, that'd be called by the I/O completion handler on the buffer > containing that dquot. > > > And decyphering all the macro crap it seems that the function that wakes > > it up is xfs_trans_chunk_committed, or xfs_trans_uncommit. > > Right (the former, at this point in the code). > > > The above xfs_qm_dqunpin_wait still looks awfully racy, and the > > xfs_log_force, which I'm assuming wakes up whoever is suppose to wake up > > kswapd0, doesn't have a return code check. So if it failed to do > > The logforce isn't race-critical here - its ensuring writeout > of previously logged buffers is started before we go to sleep > waiting for the driver to wake us up when its done. > > An earlier I/O error on the journal is the only thing the log > force can return as an error there, which isnt useful at that > point anyway (we're in a kernel thread trying to free mem). > > > whatever the hell it's doing (that code gives me a headache), it looks > > Heh, likewise. I have voodoo dolls of one or two of the early > XFS folks that I like to poke with needles occasionally.. :) > > > like this guy might sleep forever holding a lock that will prevent > > others from freeing kernel memory. > > It will sleep until the previously initiated buffer write is done. > AFAICT, we aren't seeing the I/O completion here for some reason... > which points more to a possible device driver or h/ware issue (that > is the usual root cause of this sort of hang, anyway). > > cheers.
Hey, i think i found something. My quota on my huge device is broken. (inferno -- 18014398504855404 0 0 18446744073709551519 0 0) I cant found a way to re-initialize it. But anyway, at this point i dont need it, trying to disable the quota usage. We will see....
Thanks a lot!
Janos
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