svn commit: r299906 - head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs

[Andriy Gapon]

Author: avg
Date: Mon May 16 06:40:51 2016
New Revision: 299906
URL: https://svnweb.freebsd.org/changeset/base/299906

Log:
  add zfs_vptocnp with special handling for snapshots under .zfs
  
  The logic is similar to that already present in zfs_dirlook() to handle
  a dot-dot lookup on a root vnode of a snapshot mounted under
  .zfs/snapshot/.
  illumos does not have an equivalent of vop_vptocnp, so there only the
  lookup had to be patched up.
  
  MFC after:	4 weeks

Modified:
  head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_vnops.c

Modified: head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_vnops.c
==============================================================================
--- head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_vnops.c	Mon May 16 06:40:17 2016	(r299905)
+++ head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_vnops.c	Mon May 16 06:40:51 2016	(r299906)
@@ -7160,6 +7160,44 @@ zfs_freebsd_aclcheck(ap)
 	return (EOPNOTSUPP);
 }
 
+static int
+zfs_vptocnp(struct vop_vptocnp_args *ap)
+{
+	vnode_t *covered_vp;
+	vnode_t *vp = ap->a_vp;;
+	zfsvfs_t *zfsvfs = vp->v_vfsp->vfs_data;
+	znode_t *zp = VTOZ(vp);
+	uint64_t parent;
+	int ltype;
+	int error;
+
+	/*
+	 * If we are a snapshot mounted under .zfs, run the operation
+	 * on the covered vnode.
+	 */
+	if ((error = sa_lookup(zp->z_sa_hdl,
+	    SA_ZPL_PARENT(zfsvfs), &parent, sizeof (parent))) != 0)
+		return (error);
+
+	if (zp->z_id != parent || zfsvfs->z_parent == zfsvfs)
+		return (vop_stdvptocnp(ap));
+
+	covered_vp = vp->v_mount->mnt_vnodecovered;
+	vhold(covered_vp);
+	ltype = VOP_ISLOCKED(vp);
+	VOP_UNLOCK(vp, 0);
+	error = vget(covered_vp, LK_EXCLUSIVE | LK_VNHELD, curthread);
+	if (error == 0) {
+		error = VOP_VPTOCNP(covered_vp, ap->a_vpp, ap->a_cred,
+		    ap->a_buf, ap->a_buflen);
+		vput(covered_vp);
+	}
+	vn_lock(vp, ltype | LK_RETRY);
+	if ((vp->v_iflag & VI_DOOMED) != 0)
+		error = SET_ERROR(ENOENT);
+	return (error);
+}
+
 struct vop_vector zfs_vnodeops;
 struct vop_vector zfs_fifoops;
 struct vop_vector zfs_shareops;
@@ -7205,6 +7243,7 @@ struct vop_vector zfs_vnodeops = {
 	.vop_aclcheck =		zfs_freebsd_aclcheck,
 	.vop_getpages =		zfs_freebsd_getpages,
 	.vop_putpages =		zfs_freebsd_putpages,
+	.vop_vptocnp =		zfs_vptocnp,
 };
 
 struct vop_vector zfs_fifoops = {