Date: Wed, 13 Jun 2001 16:29:50 -0700 From: Kirk McKusick <mckusick@mckusick.com> To: Dag-Erling Smorgrav <des@ofug.org> Cc: current@freebsd.org Subject: Re: worklist_remove panic Message-ID: <200106132329.QAA27987@beastie.mckusick.com> In-Reply-To: Your message of "26 May 2001 21:25:32 %2B0200." <xzphey7diab.fsf@flood.ping.uio.no>
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I have checked in revision 1.99 to ffs_softdep.c which
builds on the change in revision 1.98 by Tor.Egge@fast.no.
The symptom being treated in 1.98 was to avoid freeing a
pagedep dependency if there was still a newdirblk dependency
referencing it. That change is correct and no longer prints
the warning message ``handle_written_filepage: active pagedep''
when it occurs. The other part of revision 1.98 was to panic
with ``deallocate_dependencies: active pagedep'' when a
newdirblk dependency was encountered during a file truncation.
This fix removes that panic and replaces it with code to find
and delete the newdirblk dependency so that the truncation can
succeed. This delta should clear up the recent problems that
folks have been having with soft updates.
Kirk McKusick
=-=-=-=-=
To: current@freebsd.org
Cc: mckusick@mckusick.com
Subject: worklist_remove panic
From: Dag-Erling Smorgrav <des@ofug.org>
Date: 26 May 2001 21:25:32 +0200
No dump (dumps seem to have been broken for about a month now), but a
stacktrace from DDB:
kernel: type 12 trap, code=0
Stopped at worklist_remove+0x1c: cmpw $0,0xa(%ecx)
db> trace
worklist_remove(deadc0de) at worklist_remove+0x1c
free_diradd(deadc0de) at free_diradd+0x26
free_newdirblk(c2e45cd0) at free_newdirblk+0x32
handle_written_inodeblock(c287b200,c6323480) at handle_written_inodeblock+0x2b2
softdep_disk_write_complete(c6323480) at softdep_disk_write_complete+0x6a
bufdone(c6323480,cf2c7f54,c014de93,c6323480,c258b280) at bufdone+0x101
bufdonebio(c6323480) at bufdonebio+0xe
ad_interrupt(c2c5f940,c2564300,cf2c7f7c,c01ba6e4,c258b280) at ad_interrupt+0x3ef
ata_intr(c258b280) at ata_intr+0xae
ithread_loop(c258b200,cf2c7fa8) at ithread_loop+0x424
fork_exit(c01ba2c0,c258b200,cf2c7fa8) at fork_exit+0xf4
fork_trampoline() at fork_trampoline+0x8
db> panic
panic: from debugger
Debugger("panic")
Stopped at worklist_remove+0x1c: cmpw $0,0xa(%ecx)
db>
panic: from debugger
Uptime: 1d0h12m13s
dumping to dev ad0b, offset 131104
dump ata0: resetting devices .. panic: witness_restore: lock (sleep mutex) Giant not locked
Uptime: 1d0h12m13s
Dump already in progress, bailing...
Automatic reboot in 15 seconds - press a key on the console to abort
des@des ~% gdb -k
GNU gdb 4.18
Copyright 1998 Free Software Foundation, Inc.
GDB is free software, covered by the GNU General Public License, and you are
welcome to change it and/or distribute copies of it under certain conditions.
Type "show copying" to see the conditions.
There is absolutely no warranty for GDB. Type "show warranty" for details.
This GDB was configured as "i386-unknown-freebsd".
(kgdb) exec-file /boot/kernel/kernel
(kgdb) symbol-file /sys/compile/DES/kernel.debug
Reading symbols from /sys/compile/DES/kernel.debug...done.
(kgdb) l *(worklist_remove+0x1c)
0xc0261750 is in worklist_remove (../../ufs/ffs/ffs_softdep.c:432).
427 struct worklist *item;
428 {
429
430 if (lk.lkt_held == -1)
431 panic("worklist_remove: lock not held");
432 if ((item->wk_state & ONWORKLIST) == 0) {
433 FREE_LOCK(&lk);
434 panic("worklist_remove: not on list");
435 }
436 item->wk_state &= ~ONWORKLIST;
(kgdb) l *(free_diradd+0x26)
0xc02640fa is in free_diradd (../../ufs/ffs/ffs_softdep.c:2601).
2596 #ifdef DEBUG
2597 if (lk.lkt_held == -1)
2598 panic("free_diradd: lock not held");
2599 #endif
2600 WORKLIST_REMOVE(&dap->da_list);
2601 LIST_REMOVE(dap, da_pdlist);
2602 if ((dap->da_state & DIRCHG) == 0) {
2603 pagedep = dap->da_pagedep;
2604 } else {
2605 dirrem = dap->da_previous;
(kgdb) l *(free_newdirblk+0x32)
0xc026345e is in free_newdirblk (../../ufs/ffs/ffs_softdep.c:2033).
2028 */
2029 pagedep = newdirblk->db_pagedep;
2030 pagedep->pd_state &= ~NEWBLOCK;
2031 if ((pagedep->pd_state & ONWORKLIST) == 0)
2032 while ((dap = LIST_FIRST(&pagedep->pd_pendinghd)) != NULL)
2033 free_diradd(dap);
2034 /*
2035 * If no dependencies remain, the pagedep will be freed.
2036 */
2037 for (i = 0; i < DAHASHSZ; i++)
After this panic, fsck complained of bad superblocks on all file
systems.
By the way, fsck is intolerably slow these days: more than twenty
minutes for 'fsck -y' of a 5.5 GB filesystem (roughly 380,000 files)
on a recent and far from sluggish IBM IDE drive. Most (nearly all) of
that time is spent in phase 2.
DES
--
Dag-Erling Smorgrav - des@ofug.org
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