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softdep_sync_metadata: If vp is a block device it may have new I/O requests 

posted for it even if the vnode is locked. This will deadlock with wmesg
"softgetdbuf" if it gets a BMSAFEMAP dependency as here we have "bp == nbp"
and try to get a buffer we already own.

Approved by: Frank van der Linden <fvdl@netbsd.org>
This commit is contained in:
hannken 2006-06-12 16:37:00 +00:00
parent 19d35b3135
commit 442bf57d1c
1 changed files with 26 additions and 19 deletions
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45
sys/ufs/ffs/ffs_softdep.c
View File

@ -1,4 +1,4 @@
/* $NetBSD: ffs_softdep.c,v 1.74 2006/05/14 21:32:45 elad Exp $ */
/* $NetBSD: ffs_softdep.c,v 1.75 2006/06/12 16:37:00 hannken Exp $ */
/*
* Copyright 1998 Marshall Kirk McKusick. All Rights Reserved.
@ -33,7 +33,7 @@
*/
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: ffs_softdep.c,v 1.74 2006/05/14 21:32:45 elad Exp $");
__KERNEL_RCSID(0, "$NetBSD: ffs_softdep.c,v 1.75 2006/06/12 16:37:00 hannken Exp $");
#include <sys/param.h>
#include <sys/buf.h>
@ -4877,7 +4877,7 @@ softdep_sync_metadata(v)
struct allocindir *aip;
struct buf *bp, *nbp;
struct worklist *wk;
int i, error, waitfor;
int i, error, waitfor, must_sync;
/*
* Check whether this vnode is involved in a filesystem
@ -4926,6 +4926,7 @@ loop:
* As we hold the buffer locked, none of its dependencies
* will disappear.
*/
must_sync = 0;
for (wk = LIST_FIRST(&bp->b_dep); wk;
wk = LIST_NEXT(wk, wk_list)) {
switch (wk->wk_type) {
@ -5038,23 +5039,25 @@ loop:
case D_BMSAFEMAP:
/*
* This case should never happen if the vnode has
* been properly sync'ed. However, if this function
* is used at a place where the vnode has not yet
* been sync'ed, this dependency can show up. So,
* rather than panic, just flush it.
* If the vnode is a block device associated with a
* file system it may have new I/O requests posted for
* it even if the vnode is locked. For other vnodes
* this case should never happen if the vnode has
* been properly sync'ed. As this dependency can show
* up we have to deal with it.
* For a BMSAFEMAP dependency its sm_buf points to the
* buffer holding it so all we can do is to note this
* condition so bp gets written synchronously if
* waitfor is not MNT_NOWAIT.
*/
nbp = WK_BMSAFEMAP(wk)->sm_buf;
if (getdirtybuf(&nbp, waitfor) == 0)
break;
FREE_LOCK(&lk);
if (waitfor == MNT_NOWAIT) {
bawrite(nbp);
} else if ((error = VOP_BWRITE(nbp)) != 0) {
bawrite(bp);
return (error);
}
ACQUIRE_LOCK(&lk);
KASSERT(nbp == bp);
#ifdef DIAGNOSTIC
if (vp->v_type != VBLK)
vprint("softdep_sync_metadata: bmsafemap", vp);
#endif
if (waitfor != MNT_NOWAIT)
must_sync = 1;
break;
default:
@ -5066,7 +5069,11 @@ loop:
(void) getdirtybuf(&bp->b_vnbufs.le_next, MNT_WAIT);
nbp = bp->b_vnbufs.le_next;
FREE_LOCK(&lk);
bawrite(bp);
if (must_sync) {
if ((error = VOP_BWRITE(bp)) != 0)
return error;
} else
bawrite(bp);
ACQUIRE_LOCK(&lk);
if (nbp != NULL) {
bp = nbp;