OpenZFS 7336 - vfork and O_CLOEXEC causes zfs_mount EBUSY

Porting notes:
- statvfs64 is replaced by statfs64.
- ZFS_SUPER_MAGIC definition moved in include/sys/fs/zfs.h
  to share it between user and kernel space.

Authored by: Prakash Surya <[email protected]>
Reviewed by: Matt Ahrens <[email protected]>
Reviewed by: Paul Dagnelie <[email protected]>
Reviewed by: Robert Mustacchi <[email protected]>
Reviewed-by: Brian Behlendorf <[email protected]>
Ported-by: George Melikov <[email protected]>

OpenZFS-issue: https://www.illumos.org/issues/7336
OpenZFS-commit: https://github.com/openzfs/openzfs/commit/dd862f6d
Closes #5651 

2 files changed, 51 insertions, 0 deletions

diff --git a/tests/zfs-tests/tests/functional/cli_root/zfs_mount/Makefile.am b/tests/zfs-tests/tests/functional/cli_root/zfs_mount/Makefile.am
index c6ae99c6b..f26120e2f 100644
--- a/tests/zfs-tests/tests/functional/cli_root/zfs_mount/Makefile.am
+++ b/tests/zfs-tests/tests/functional/cli_root/zfs_mount/Makefile.am
@@ -15,4 +15,5 @@ dist_pkgdata_SCRIPTS = \
 	zfs_mount_009_neg.ksh \
 	zfs_mount_010_neg.ksh \
 	zfs_mount_011_neg.ksh \
+	zfs_mount_012_neg.ksh \
 	zfs_mount_all_001_pos.ksh
diff --git a/tests/zfs-tests/tests/functional/cli_root/zfs_mount/zfs_mount_012_neg.ksh b/tests/zfs-tests/tests/functional/cli_root/zfs_mount/zfs_mount_012_neg.ksh
new file mode 100755
index 000000000..ec1ff433a
--- /dev/null
+++ b/tests/zfs-tests/tests/functional/cli_root/zfs_mount/zfs_mount_012_neg.ksh
@@ -0,0 +1,50 @@
+#!/bin/ksh -p
+#
+# This file and its contents are supplied under the terms of the
+# Common Development and Distribution License ("CDDL"), version 1.0.
+# You may only use this file in accordance with the terms of version
+# 1.0 of the CDDL.
+#
+# A full copy of the text of the CDDL should have accompanied this
+# source.  A copy of the CDDL is also available via the Internet at
+# http://www.illumos.org/license/CDDL.
+#
+
+#
+# Copyright (c) 2015 by Delphix. All rights reserved.
+#
+
+. $STF_SUITE/include/libtest.shlib
+
+#
+# DESCRIPTION:
+# Verify that zfs mount should fail with a non-empty directory
+#
+# STRATEGY:
+# 1. Unmount the dataset
+# 2. Create a new empty directory
+# 3. Set the dataset's mountpoint
+# 4. Attempt to mount the dataset
+# 5. Verify the mount succeeds
+# 6. Unmount the dataset
+# 7. Create a file in the directory created in step 2
+# 8. Attempt to mount the dataset
+# 9. Verify the mount fails
+#
+
+verify_runnable "both"
+
+log_assert "zfs mount fails with non-empty directory"
+
+fs=$TESTPOOL/$TESTFS
+
+log_must $ZFS umount $fs
+log_must mkdir -p $TESTDIR
+log_must $ZFS set mountpoint=$TESTDIR $fs
+log_must $ZFS mount $fs
+log_must $ZFS umount $fs
+log_must touch $TESTDIR/testfile.$$
+log_mustnot $ZFS mount $fs
+log_must rm -rf $TESTDIR
+
+log_pass "zfs mount fails non-empty directory as expected."