4521 zfstest is trying to execute evil "zfs unmount -a"

illumos/illumos-gate@8808ac5dae
8808ac5dae

https://www.illumos.org/issues/4521
  zfstest is trying to execute evil "zfs unmount -a", which fails (fortunately,
  as it would otherwise leave me with my ~ missing):
  03:44:11.86 cannot unmount '/export/home/yuri': Device busy cannot unmount '/
  export/home': Device busy
  03:44:11.86 ERROR: /usr/sbin/zfs unmount -a exited 1
  This affects, at least, zfs_mount_009_neg and zfs_mount_all_001_pos, both
  failing on that step. The pool containing the /export/home hierarchy is
  included in KEEP variable, but it doesn't seem to affect anything here.

Reviewed by: Andriy Gapon <avg@FreeBSD.org>
Reviewed by: Dan McDonald <danmcd@omniti.com>
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Reviewed by: John Kennedy <john.kennedy@delphix.com>
Approved by: Robert Mustacchi <rm@joyent.com>
Author: Yuri Pankov <yuri.pankov@nexenta.com>

cmd/zfs/zfs_main.c

@@ -26,9 +26,9 @@
  * Copyright (c) 2012, Joyent, Inc. All rights reserved.
  * Copyright (c) 2011-2012 Pawel Jakub Dawidek. All rights reserved.
  * Copyright (c) 2013 Steven Hartland.  All rights reserved.
- * Copyright 2013 Nexenta Systems, Inc.  All rights reserved.
  * Copyright (c) 2014 Integros [integros.com]
  * Copyright 2016 Igor Kozhukhov <ikozhukhov@gmail.com>.
+ * Copyright 2016 Nexenta Systems, Inc.
  */
 
 #include <assert.h>
@@ -6388,6 +6388,15 @@ unshare_unmount(int op, int argc, char **argv)
 				continue;
 			}
 
+			/*
+			 * Ignore datasets that are excluded/restricted by
+			 * parent pool name.
+			 */
+			if (zpool_skip_pool(zfs_get_pool_name(zhp))) {
+				zfs_close(zhp);
+				continue;
+			}
+
 			switch (op) {
 			case OP_SHARE:
 				verify(zfs_prop_get(zhp, ZFS_PROP_SHARENFS,

lib/libzfs/common/libzfs.h

@@ -25,8 +25,8 @@
  * Copyright (c) 2011, 2015 by Delphix. All rights reserved.
  * Copyright (c) 2012, Joyent, Inc. All rights reserved.
  * Copyright (c) 2013 Steven Hartland. All rights reserved.
- * Copyright 2013 Nexenta Systems, Inc.  All rights reserved.
  * Copyright (c) 2014 Integros [integros.com]
+ * Copyright 2016 Nexenta Systems, Inc.
  */
 
 #ifndef	_LIBZFS_H
@@ -220,6 +220,7 @@ extern void zpool_free_handles(libzfs_handle_t *);
  */
 typedef int (*zpool_iter_f)(zpool_handle_t *, void *);
 extern int zpool_iter(libzfs_handle_t *, zpool_iter_f, void *);
+extern boolean_t zpool_skip_pool(const char *);
 
 /*
  * Functions to create and destroy pools
@@ -409,6 +410,7 @@ extern void zfs_close(zfs_handle_t *);
 extern zfs_type_t zfs_get_type(const zfs_handle_t *);
 extern const char *zfs_get_name(const zfs_handle_t *);
 extern zpool_handle_t *zfs_get_pool_handle(const zfs_handle_t *);
+extern const char *zfs_get_pool_name(const zfs_handle_t *);
 
 /*
  * Property management functions.  Some functions are shared with the kernel,

lib/libzfs/common/libzfs_config.c

@@ -27,6 +27,7 @@
 /*
  * Copyright (c) 2012 by Delphix. All rights reserved.
  * Copyright (c) 2015 by Syneto S.R.L. All rights reserved.
+ * Copyright 2016 Nexenta Systems, Inc.
  */
 
 /*
@@ -338,33 +339,47 @@ zpool_refresh_stats(zpool_handle_t *zhp, boolean_t *missing)
 }
 
 /*
- * If the __ZFS_POOL_RESTRICT environment variable is set we only iterate over
+ * The following environment variables are undocumented
- * pools it lists.
+ * and should be used for testing purposes only:
  *
- * This is an undocumented feature for use during testing only.
+ * __ZFS_POOL_EXCLUDE - don't iterate over the pools it lists
+ * __ZFS_POOL_RESTRICT - iterate only over the pools it lists
  *
  * This function returns B_TRUE if the pool should be skipped
  * during iteration.
  */
-static boolean_t
+boolean_t
-check_restricted(const char *poolname)
+zpool_skip_pool(const char *poolname)
 {
 	static boolean_t initialized = B_FALSE;
-	static char *restricted = NULL;
+	static const char *exclude = NULL;
+	static const char *restricted = NULL;
 
 	const char *cur, *end;
-	int len, namelen;
+	int len;
+	int namelen = strlen(poolname);
 
 	if (!initialized) {
 		initialized = B_TRUE;
+		exclude = getenv("__ZFS_POOL_EXCLUDE");
 		restricted = getenv("__ZFS_POOL_RESTRICT");
 	}
 
+	if (exclude != NULL) {
+		cur = exclude;
+		do {
+			end = strchr(cur, ' ');
+			len = (NULL == end) ? strlen(cur) : (end - cur);
+			if (len == namelen && 0 == strncmp(cur, poolname, len))
+				return (B_TRUE);
+			cur += (len + 1);
+		} while (NULL != end);
+	}
+
 	if (NULL == restricted)
 		return (B_FALSE);
 
 	cur = restricted;
-	namelen = strlen(poolname);
 	do {
 		end = strchr(cur, ' ');
 		len = (NULL == end) ? strlen(cur) : (end - cur);
@@ -402,7 +417,7 @@ zpool_iter(libzfs_handle_t *hdl, zpool_iter_f func, void *data)
 	for (cn = uu_avl_first(hdl->libzfs_ns_avl); cn != NULL;
 	    cn = uu_avl_next(hdl->libzfs_ns_avl, cn)) {
 
-		if (check_restricted(cn->cn_name))
+		if (zpool_skip_pool(cn->cn_name))
 			continue;
 
 		if (zpool_open_silent(hdl, cn->cn_name, &zhp) != 0) {
@@ -440,7 +455,7 @@ zfs_iter_root(libzfs_handle_t *hdl, zfs_iter_f func, void *data)
 	for (cn = uu_avl_first(hdl->libzfs_ns_avl); cn != NULL;
 	    cn = uu_avl_next(hdl->libzfs_ns_avl, cn)) {
 
-		if (check_restricted(cn->cn_name))
+		if (zpool_skip_pool(cn->cn_name))
 			continue;
 
 		if ((zhp = make_dataset_handle(hdl, cn->cn_name)) == NULL)

lib/libzfs/common/libzfs_dataset.c

@@ -27,8 +27,8 @@
  * Copyright (c) 2011-2012 Pawel Jakub Dawidek. All rights reserved.
  * Copyright (c) 2013 Martin Matuska. All rights reserved.
  * Copyright (c) 2013 Steven Hartland. All rights reserved.
- * Copyright 2013 Nexenta Systems, Inc.  All rights reserved.
  * Copyright (c) 2014 Integros [integros.com]
+ * Copyright 2016 Nexenta Systems, Inc.
  */
 
 #include <ctype.h>
@@ -2906,6 +2906,15 @@ zfs_get_name(const zfs_handle_t *zhp)
 	return (zhp->zfs_name);
 }
 
+/*
+ * Returns the name of the parent pool for the given zfs handle.
+ */
+const char *
+zfs_get_pool_name(const zfs_handle_t *zhp)
+{
+	return (zhp->zpool_hdl->zpool_name);
+}
+
 /*
  * Returns the type of the given zfs handle.
  */