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Resolve two deadlocks that could be caused by busy md device backed

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by vnode. Allow for md thread and the thread that owns lock on vnode
backing the md device to do the write even when runningbufspace is
exhausted.

Tested by:	Peter Holm
Reviewed by:	tegge
MFC after:	2 weeks
This commit is contained in:
Konstantin Belousov 2006-12-14 11:34:07 +00:00
parent 7eb5016ab5
commit 3b7b5496a7
3 changed files with 12 additions and 1 deletions
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9
sys/dev/md/md.c
View File

@ -693,6 +693,8 @@ md_kthread(void *arg)
mtx_lock_spin(&sched_lock);
sched_prio(curthread, PRIBIO);
mtx_unlock_spin(&sched_lock);
if (sc->type == MD_VNODE)
curthread->td_pflags |= TDP_NORUNNINGBUF;
for (;;) {
mtx_lock(&sc->queue_mtx);
@ -923,6 +925,7 @@ mdcreate_vnode(struct md_s *sc, struct md_ioctl *mdio, struct thread *td)
VFS_UNLOCK_GIANT(vfslocked);
return (error ? error : EINVAL);
}
nd.ni_vp->v_vflag |= VV_MD;
VOP_UNLOCK(nd.ni_vp, 0, td);
if (mdio->md_fwsectors != 0)
@ -936,6 +939,9 @@ mdcreate_vnode(struct md_s *sc, struct md_ioctl *mdio, struct thread *td)
error = mdsetcred(sc, td->td_ucred);
if (error != 0) {
vn_lock(nd.ni_vp, LK_EXCLUSIVE | LK_RETRY, td);
nd.ni_vp->v_vflag &= ~VV_MD;
VOP_UNLOCK(nd.ni_vp, 0, td);
(void)vn_close(nd.ni_vp, flags, td->td_ucred, td);
VFS_UNLOCK_GIANT(vfslocked);
return (error);
@ -966,6 +972,9 @@ mddestroy(struct md_s *sc, struct thread *td)
mtx_destroy(&sc->queue_mtx);
if (sc->vnode != NULL) {
vfslocked = VFS_LOCK_GIANT(sc->vnode->v_mount);
vn_lock(sc->vnode, LK_EXCLUSIVE | LK_RETRY, td);
sc->vnode->v_vflag &= ~VV_MD;
VOP_UNLOCK(sc->vnode, 0, td);
(void)vn_close(sc->vnode, sc->flags & MD_READONLY ?
FREAD : (FREAD|FWRITE), sc->cred, td);
VFS_UNLOCK_GIANT(vfslocked);

3
sys/kern/vfs_bio.c
View File

@ -871,7 +871,8 @@ bufwrite(struct buf *bp)
* or syncer daemon trying to clean up as that can lead
* to deadlock.
*/
if ((curthread->td_pflags & TDP_NORUNNINGBUF) == 0)
if ((curthread->td_pflags & TDP_NORUNNINGBUF) == 0 &&
(bp->b_vp->v_vflag & VV_MD) == 0)
waitrunningbufspace();
}

1
sys/sys/vnode.h
View File

@ -254,6 +254,7 @@ struct xvnode {
#define VV_PROCDEP 0x0100 /* vnode is process dependent */
#define VV_NOKNOTE 0x0200 /* don't activate knotes on this vnode */
#define VV_DELETED 0x0400 /* should be removed */
#define VV_MD 0x0800 /* vnode backs the md device */
/*
* Vnode attributes. A field value of VNOVAL represents a field whose value