#include <sys/mntent.h>
#include <sys/mount.h>
#include <sys/stat.h>
+#include <sys/vfs.h>
#include <libzfs.h>
return (SHARED_NOT_SHARED);
}
-/*
- * Returns true if the specified directory is empty. If we can't open the
- * directory at all, return true so that the mount can fail with a more
- * informative error message.
- */
static boolean_t
-dir_is_empty(const char *dirname)
+dir_is_empty_stat(const char *dirname)
+{
+ struct stat st;
+
+ /*
+ * We only want to return false if the given path is a non empty
+ * directory, all other errors are handled elsewhere.
+ */
+ if (stat(dirname, &st) < 0 || !S_ISDIR(st.st_mode)) {
+ return (B_TRUE);
+ }
+
+ /*
+ * An empty directory will still have two entries in it, one
+ * entry for each of "." and "..".
+ */
+ if (st.st_size > 2) {
+ return (B_FALSE);
+ }
+
+ return (B_TRUE);
+}
+
+static boolean_t
+dir_is_empty_readdir(const char *dirname)
{
DIR *dirp;
struct dirent64 *dp;
return (B_TRUE);
}
+/*
+ * Returns true if the specified directory is empty. If we can't open the
+ * directory at all, return true so that the mount can fail with a more
+ * informative error message.
+ */
+static boolean_t
+dir_is_empty(const char *dirname)
+{
+ struct statfs64 st;
+
+ /*
+ * If the statvfs call fails or the filesystem is not a ZFS
+ * filesystem, fall back to the slow path which uses readdir.
+ */
+ if ((statfs64(dirname, &st) != 0) ||
+ (st.f_type != ZFS_SUPER_MAGIC)) {
+ return (dir_is_empty_readdir(dirname));
+ }
+
+ /*
+ * At this point, we know the provided path is on a ZFS
+ * filesystem, so we can use stat instead of readdir to
+ * determine if the directory is empty or not. We try to avoid
+ * using readdir because that requires opening "dirname"; this
+ * open file descriptor can potentially end up in a child
+ * process if there's a concurrent fork, thus preventing the
+ * zfs_mount() from otherwise succeeding (the open file
+ * descriptor inherited by the child process will cause the
+ * parent's mount to fail with EBUSY). The performance
+ * implications of replacing the open, read, and close with a
+ * single stat is nice; but is not the main motivation for the
+ * added complexity.
+ */
+ return (dir_is_empty_stat(dirname));
+}
+
/*
* Checks to see if the mount is active. If the filesystem is mounted, we fill
* in 'where' with the current mountpoint, and return 1. Otherwise, we return
[tests/functional/cli_root/zfs_mount]
tests = ['zfs_mount_001_pos', 'zfs_mount_002_pos', 'zfs_mount_003_pos',
'zfs_mount_004_pos', 'zfs_mount_005_pos', 'zfs_mount_008_pos',
- 'zfs_mount_010_neg', 'zfs_mount_011_neg']
+ 'zfs_mount_010_neg', 'zfs_mount_011_neg', 'zfs_mount_012_neg']
[tests/functional/cli_root/zfs_promote]
tests = ['zfs_promote_001_pos', 'zfs_promote_002_pos', 'zfs_promote_003_pos',
--- /dev/null
+#!/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."
projects / zfs / commitdiff