Author: mjg
Date: Thu Mar 16 08:51:30 2017
New Revision: 315400
URL: https://svnweb.freebsd.org/changeset/base/315400
Log:
MFC r309425,r312645,r312598,r312621:
vfs: provide fake locking primitives for the crossmp vnode
Since the vnode is only expected to be shared locked, we can save a
little overhead by only pretending we are locking in the first place.
==
Provide fallback VOP methods for crossmp vnode.
In particular, crossmp vnode might leak into rename code.
==
vfs: hide the getvnode NULL mp message behind DIAGNOSTIC
Since crossmp vnode changes the message was being printed on each boot.
==
Improve debugging printf.
Modified:
stable/11/sys/kern/vfs_lookup.c
stable/11/sys/kern/vfs_subr.c
Directory Properties:
stable/11/ (props changed)
Modified: stable/11/sys/kern/vfs_lookup.c
==============================================================================
--- stable/11/sys/kern/vfs_lookup.c Thu Mar 16 08:40:47 2017
(r315399)
+++ stable/11/sys/kern/vfs_lookup.c Thu Mar 16 08:51:30 2017
(r315400)
@@ -79,6 +79,65 @@ uma_zone_t namei_zone;
/* Placeholder vnode for mp traversal. */
static struct vnode *vp_crossmp;
+static int
+crossmp_vop_islocked(struct vop_islocked_args *ap)
+{
+
+ return (LK_SHARED);
+}
+
+static int
+crossmp_vop_lock1(struct vop_lock1_args *ap)
+{
+ struct vnode *vp;
+ struct lock *lk;
+ const char *file;
+ int flags, line;
+
+ vp = ap->a_vp;
+ lk = vp->v_vnlock;
+ flags = ap->a_flags;
+ file = ap->a_file;
+ line = ap->a_line;
+
+ if ((flags & LK_SHARED) == 0)
+ panic("invalid lock request for crossmp");
+
+ WITNESS_CHECKORDER(&lk->lock_object, LOP_NEWORDER, file, line,
+ flags & LK_INTERLOCK ? &VI_MTX(vp)->lock_object : NULL);
+ WITNESS_LOCK(&lk->lock_object, 0, file, line);
+ if ((flags & LK_INTERLOCK) != 0)
+ VI_UNLOCK(vp);
+ LOCK_LOG_LOCK("SLOCK", &lk->lock_object, 0, 0, ap->a_file, line);
+ return (0);
+}
+
+static int
+crossmp_vop_unlock(struct vop_unlock_args *ap)
+{
+ struct vnode *vp;
+ struct lock *lk;
+ int flags;
+
+ vp = ap->a_vp;
+ lk = vp->v_vnlock;
+ flags = ap->a_flags;
+
+ if ((flags & LK_INTERLOCK) != 0)
+ VI_UNLOCK(vp);
+ WITNESS_UNLOCK(&lk->lock_object, 0, LOCK_FILE, LOCK_LINE);
+ LOCK_LOG_LOCK("SUNLOCK", &lk->lock_object, 0, 0, LOCK_FILE,
+ LOCK_LINE);
+ return (0);
+}
+
+static struct vop_vector crossmp_vnodeops = {
+ .vop_default = &default_vnodeops,
+ .vop_islocked = crossmp_vop_islocked,
+ .vop_lock1 = crossmp_vop_lock1,
+ .vop_unlock = crossmp_vop_unlock,
+};
+
struct nameicap_tracker {
struct vnode *dp;
TAILQ_ENTRY(nameicap_tracker) nm_link;
@@ -95,10 +154,7 @@ nameiinit(void *dummy __unused)
UMA_ALIGN_PTR, 0);
nt_zone = uma_zcreate("rentr", sizeof(struct nameicap_tracker),
NULL, NULL, NULL, NULL, sizeof(void *), 0);
- getnewvnode("crossmp", NULL, &dead_vnodeops, &vp_crossmp);
- vn_lock(vp_crossmp, LK_EXCLUSIVE);
- VN_LOCK_ASHARE(vp_crossmp);
- VOP_UNLOCK(vp_crossmp, 0);
+ getnewvnode("crossmp", NULL, &crossmp_vnodeops, &vp_crossmp);
}
SYSINIT(vfs, SI_SUB_VFS, SI_ORDER_SECOND, nameiinit, NULL);
Modified: stable/11/sys/kern/vfs_subr.c
==============================================================================
--- stable/11/sys/kern/vfs_subr.c Thu Mar 16 08:40:47 2017
(r315399)
+++ stable/11/sys/kern/vfs_subr.c Thu Mar 16 08:51:30 2017
(r315400)
@@ -1419,12 +1419,14 @@ alloc:
vp->v_op = vops;
v_init_counters(vp);
vp->v_bufobj.bo_ops = &buf_ops_bio;
+#ifdef DIAGNOSTIC
+ if (mp == NULL && vops != &dead_vnodeops)
+ printf("NULL mp in getnewvnode(9), tag %s\n", tag);
+#endif
#ifdef MAC
mac_vnode_init(vp);
if (mp != NULL && (mp->mnt_flag & MNT_MULTILABEL) == 0)
mac_vnode_associate_singlelabel(mp, vp);
- else if (mp == NULL && vops != &dead_vnodeops)
- printf("NULL mp in getnewvnode()\n");
#endif
if (mp != NULL) {
vp->v_bufobj.bo_bsize = mp->mnt_stat.f_iosize;
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