Re: RAID-1 and Reiser4 issue: umount hangs

[Neil Brown <neilb@suse.de>]

On Sunday May 28, afreije@inn.nl wrote:
> Neil Brown wrote:
> > # echo t > /proc/sysrq-trigger
> >
> > and look at the resulting kernel messages, particularly for the
> > unmount process.  If they don't make sense to you, post them.
> >
> >   
> Tnx for your response. After recompiling the kernel with magic_sysrq
> enabled, rebooting, and repeating umount with the reiser4 md device, the
> following trace contains a reiser4-entry:

This looks very much like a reiser4 problem rather than a raid
problem, or at least you will need someone very familiar with reiser4
to understand what is going on here.

I recommend you post this information to 
   reiserfs-dev@namesys.com
(and  cc: to linux-kernel too if you like) to make sure someone
knowledgeable sees it.

I suspect reiser4 has some kernel threads that it uses.  They might
have 'obvious' names like  
   ent:....
   ktxnmgrd
from looking at the source.  Including the stack trace of these and
anything else with 'reiser4' in the trace would probably be helpful.

NeilBrown


> 
> > syslog-ng     R running     0  7581      1                7197 (NOTLB)
> > umount        D C011B591     0  7588   7200                     (NOTLB)
> > f6643c98 00000000 c1808320 c011b591 f7db5ad0 f4d18c00 003d092a 00000000
> > 00000000 f7db5ad0 c1808320 00000000 f4d18c00 003d092a f6b33540 c1808320
> > 00000000 f4d18c00 003d092a f6b33540 f6b33668 c1808320 00000000 f6643cfc
> > Call Trace:
> > [<c011b591>] __wake_up_common+0x41/0x70
> > [<c0318346>] io_schedule+0x26/0x30
> > [<c01469fb>] sync_page+0x4b/0x60
> > [<c03184d5>] __wait_on_bit+0x45/0x70
> > [<c01469b0>] sync_page+0x0/0x60
> > [<c014726d>] wait_on_page_bit+0xad/0xc0
> > [<c0136a30>] wake_bit_function+0x0/0x60
> > [<c0136a30>] wake_bit_function+0x0/0x60
> > [<c01ac2f9>] jwait_io+0x59/0x80
> > [<c01c1763>] update_journal_header+0x83/0xb0
> > [<c01c272a>] commit_tx+0xca/0x110
> > [<c01c29a1>] reiser4_write_logs+0x141/0x1e0
> > [<c01b9d91>] commit_current_atom+0x171/0x2c0
> > [<c01baabf>] try_commit_txnh+0x13f/0x1e0
> > [<c01bab94>] commit_txnh+0x34/0xd0
> > [<c01b91bc>] txn_end+0x2c/0x30
> > [<c01b91d0>] txn_restart+0x10/0x30
> > [<c01b920a>] txn_restart_current+0x1a/0x20
> > [<c01b9f1f>] force_commit_atom+0x3f/0x70
> > [<c01ba03a>] txnmgr_force_commit_all+0xea/0x130
> > [<c01fcb0e>] release_format40+0x7e/0x150
> > [<c01b5ea8>] init_context+0x58/0x80
> > [<c01c8b89>] reiser4_put_super+0x89/0xf0
> > [<c01857ed>] invalidate_inodes+0x5d/0x80
> > [<c0170fb6>] generic_shutdown_super+0x156/0x160
> > [<c0171b2d>] kill_block_super+0x2d/0x50
> > [<c0170d90>] deactivate_super+0x60/0x80
> > [<c0188e1f>] sys_umount+0x3f/0x90
> > [<c01171b0>] do_page_fault+0x1c0/0x5a8
> > [<c0159bc1>] sys_munmap+0x51/0x80
> > [<c0188e87>] sys_oldumount+0x17/0x20
> > [<c010306b>] sysenter_past_esp+0x54/0x75
> 
> Freely inerpreting this trace, I'd say that the umount causes the
> reiser4 filesystem to do an extra commit, and the sync_page seems to be
> waiting for IO.
> Are there other traces of interrest?
>