svn commit: r227110 - head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs

[Pawel Jakub Dawidek]

Author: pjd
Date: Sat Nov  5 16:29:03 2011
New Revision: 227110
URL: http://svn.freebsd.org/changeset/base/227110

Log:
  In zvol_open() if the spa_namespace_lock is already held, it means that
  ZFS is trying to open and taste ZVOL as its VDEV. This is not supported,
  so return an error instead of panicing on spa_namespace_lock recursion.
  
  Reported by:	Robert Millan <rmh at debian.org>
  PR:		kern/162008
  MFC after:	3 days

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

Modified: head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zvol.c
==============================================================================
--- head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zvol.c	Sat Nov  5 16:04:57 2011	(r227109)
+++ head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zvol.c	Sat Nov  5 16:29:03 2011	(r227110)
@@ -875,6 +875,14 @@ zvol_open(struct g_provider *pp, int fla
 	zvol_state_t *zv;
 	int err = 0;
 
+	if (MUTEX_HELD(&spa_namespace_lock)) {
+		/*
+		 * If the spa_namespace_lock is being held, it means that ZFS
+		 * is trying to open ZVOL as its VDEV. This i not supported.
+		 */
+		return (EOPNOTSUPP);
+	}
+
 	mutex_enter(&spa_namespace_lock);
 
 	zv = pp->private;