Author: avg
Date: Wed Jul 13 10:18:29 2016
New Revision: 302753
URL: https://svnweb.freebsd.org/changeset/base/302753
Log:
MFC r299946: gfs_lookup_dot() does not have to acquire any locks
Modified:
stable/9/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_ctldir.c
Directory Properties:
stable/9/sys/ (props changed)
stable/9/sys/cddl/contrib/opensolaris/ (props changed)
Modified: stable/9/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_ctldir.c
==============================================================================
--- stable/9/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_ctldir.c
Wed Jul 13 10:16:45 2016 (r302752)
+++ stable/9/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_ctldir.c
Wed Jul 13 10:18:29 2016 (r302753)
@@ -534,9 +534,20 @@ zfsctl_root_lookup(vnode_t *dvp, char *n
ZFS_ENTER(zfsvfs);
if (strcmp(nm, "..") == 0) {
+#ifdef illumos
err = VFS_ROOT(dvp->v_vfsp, LK_EXCLUSIVE, vpp);
+#else
+ /*
+ * NB: can not use VFS_ROOT here as it would acquire
+ * the vnode lock of the parent (root) vnode while
+ * holding the child's (.zfs) lock.
+ */
+ znode_t *rootzp;
+
+ err = zfs_zget(zfsvfs, zfsvfs->z_root, &rootzp);
if (err == 0)
- VOP_UNLOCK(*vpp, 0);
+ *vpp = ZTOV(rootzp);
+#endif
} else {
err = gfs_vop_lookup(dvp, nm, vpp, pnp, flags, rdir,
cr, ct, direntflags, realpnp);
@@ -598,6 +609,7 @@ zfsctl_freebsd_root_lookup(ap)
vnode_t **vpp = ap->a_vpp;
cred_t *cr = ap->a_cnp->cn_cred;
int flags = ap->a_cnp->cn_flags;
+ int lkflags = ap->a_cnp->cn_lkflags;
int nameiop = ap->a_cnp->cn_nameiop;
char nm[NAME_MAX + 1];
int err;
@@ -609,8 +621,18 @@ zfsctl_freebsd_root_lookup(ap)
strlcpy(nm, ap->a_cnp->cn_nameptr, ap->a_cnp->cn_namelen + 1);
err = zfsctl_root_lookup(dvp, nm, vpp, NULL, 0, NULL, cr, NULL, NULL,
NULL);
- if (err == 0 && (nm[0] != '.' || nm[1] != '\0'))
- vn_lock(*vpp, LK_EXCLUSIVE | LK_RETRY);
+ if (err == 0 && (nm[0] != '.' || nm[1] != '\0')) {
+ if (flags & ISDOTDOT)
+ VOP_UNLOCK(dvp, 0);
+ err = vn_lock(*vpp, lkflags);
+ if (err != 0) {
+ vrele(*vpp);
+ *vpp = NULL;
+ }
+ if (flags & ISDOTDOT)
+ vn_lock(dvp, LK_EXCLUSIVE | LK_RETRY);
+ }
+
return (err);
}
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