3 files changed, 275 insertions, 38 deletions

diff --git a/module/zfs/zfs_ioctl.c b/module/zfs/zfs_ioctl.c
index 61bc4b82b165..06aae82a10e3 100644
--- a/module/zfs/zfs_ioctl.c
+++ b/module/zfs/zfs_ioctl.c
@@ -1449,7 +1449,7 @@ zfs_sb_hold(const char *name, void *tag, zfs_sb_t **zsbp, boolean_t writer)
 	int error = 0;
 
 	if (get_zfs_sb(name, zsbp) != 0)
-		error = zfs_sb_create(name, zsbp);
+		error = zfs_sb_create(name, NULL, zsbp);
 	if (error == 0) {
 		rrm_enter(&(*zsbp)->z_teardown_lock, (writer) ? RW_WRITER :
 		    RW_READER, tag);
diff --git a/module/zfs/zfs_vfsops.c b/module/zfs/zfs_vfsops.c
index f94073cbbc57..9ee7b2e8ad9b 100644
--- a/module/zfs/zfs_vfsops.c
+++ b/module/zfs/zfs_vfsops.c
@@ -262,11 +262,22 @@ zfs_register_callbacks(zfs_sb_t *zsb)
 {
 	struct dsl_dataset *ds = NULL;
 	objset_t *os = zsb->z_os;
-	boolean_t do_readonly = B_FALSE;
+	zfs_mntopts_t *zmo = zsb->z_mntopts;
 	int error = 0;
 
-	if (zfs_is_readonly(zsb) || !spa_writeable(dmu_objset_spa(os)))
-		do_readonly = B_TRUE;
+	ASSERT(zsb);
+	ASSERT(zmo);
+
+	/*
+	 * The act of registering our callbacks will destroy any mount
+	 * options we may have.  In order to enable temporary overrides
+	 * of mount options, we stash away the current values and
+	 * restore them after we register the callbacks.
+	 */
+	if (zfs_is_readonly(zsb) || !spa_writeable(dmu_objset_spa(os))) {
+		zmo->z_do_readonly = B_TRUE;
+		zmo->z_readonly = B_TRUE;
+	}
 
 	/*
 	 * Register property callbacks.
@@ -307,8 +318,25 @@ zfs_register_callbacks(zfs_sb_t *zsb)
 	if (error)
 		goto unregister;
 
-	if (do_readonly)
-		readonly_changed_cb(zsb, B_TRUE);
+	/*
+	 * Invoke our callbacks to restore temporary mount options.
+	 */
+	if (zmo->z_do_readonly)
+		readonly_changed_cb(zsb, zmo->z_readonly);
+	if (zmo->z_do_setuid)
+		setuid_changed_cb(zsb, zmo->z_setuid);
+	if (zmo->z_do_exec)
+		exec_changed_cb(zsb, zmo->z_exec);
+	if (zmo->z_do_devices)
+		devices_changed_cb(zsb, zmo->z_devices);
+	if (zmo->z_do_xattr)
+		xattr_changed_cb(zsb, zmo->z_xattr);
+	if (zmo->z_do_atime)
+		atime_changed_cb(zsb, zmo->z_atime);
+	if (zmo->z_do_relatime)
+		relatime_changed_cb(zsb, zmo->z_relatime);
+	if (zmo->z_do_nbmand)
+		nbmand_changed_cb(zsb, zmo->z_nbmand);
 
 	return (0);
 
@@ -642,8 +670,26 @@ zfs_owner_overquota(zfs_sb_t *zsb, znode_t *zp, boolean_t isgroup)
 }
 EXPORT_SYMBOL(zfs_owner_overquota);
 
+zfs_mntopts_t *
+zfs_mntopts_alloc(void)
+{
+	return (kmem_zalloc(sizeof (zfs_mntopts_t), KM_SLEEP));
+}
+
+void
+zfs_mntopts_free(zfs_mntopts_t *zmo)
+{
+	if (zmo->z_osname)
+		strfree(zmo->z_osname);
+
+	if (zmo->z_mntpoint)
+		strfree(zmo->z_mntpoint);
+
+	kmem_free(zmo, sizeof (zfs_mntopts_t));
+}
+
 int
-zfs_sb_create(const char *osname, zfs_sb_t **zsbp)
+zfs_sb_create(const char *osname, zfs_mntopts_t *zmo, zfs_sb_t **zsbp)
 {
 	objset_t *os;
 	zfs_sb_t *zsb;
@@ -664,6 +710,11 @@ zfs_sb_create(const char *osname, zfs_sb_t **zsbp)
 	}
 
 	/*
+	 * Optional temporary mount options, free'd in zfs_sb_free().
+	 */
+	zsb->z_mntopts = (zmo ? zmo : zfs_mntopts_alloc());
+
+	/*
 	 * Initialize the zfs-specific filesystem structure.
 	 * Should probably make this a kmem cache, shuffle fields,
 	 * and just bzero up to z_hold_mtx[].
@@ -892,6 +943,7 @@ zfs_sb_free(zfs_sb_t *zsb)
 	for (i = 0; i != ZFS_OBJ_MTX_SZ; i++)
 		mutex_destroy(&zsb->z_hold_mtx[i]);
 	vmem_free(zsb->z_hold_mtx, sizeof (kmutex_t) * ZFS_OBJ_MTX_SZ);
+	zfs_mntopts_free(zsb->z_mntopts);
 	kmem_free(zsb, sizeof (zfs_sb_t));
 }
 EXPORT_SYMBOL(zfs_sb_free);
@@ -1310,16 +1362,15 @@ atomic_long_t zfs_bdi_seq = ATOMIC_LONG_INIT(0);
 #endif
 
 int
-zfs_domount(struct super_block *sb, void *data, int silent)
+zfs_domount(struct super_block *sb, zfs_mntopts_t *zmo, int silent)
 {
-	zpl_mount_data_t *zmd = data;
-	const char *osname = zmd->z_osname;
+	const char *osname = zmo->z_osname;
 	zfs_sb_t *zsb;
 	struct inode *root_inode;
 	uint64_t recordsize;
 	int error;
 
-	error = zfs_sb_create(osname, &zsb);
+	error = zfs_sb_create(osname, zmo, &zsb);
 	if (error)
 		return (error);
 
@@ -1462,13 +1513,15 @@ zfs_umount(struct super_block *sb)
 EXPORT_SYMBOL(zfs_umount);
 
 int
-zfs_remount(struct super_block *sb, int *flags, char *data)
+zfs_remount(struct super_block *sb, int *flags, zfs_mntopts_t *zmo)
 {
-	/*
-	 * All namespace flags (MNT_*) and super block flags (MS_*) will
-	 * be handled by the Linux VFS.  Only handle custom options here.
-	 */
-	return (0);
+	zfs_sb_t *zsb = sb->s_fs_info;
+	int error;
+
+	zfs_unregister_callbacks(zsb);
+	error = zfs_register_callbacks(zsb);
+
+	return (error);
 }
 EXPORT_SYMBOL(zfs_remount);
 
diff --git a/module/zfs/zpl_super.c b/module/zfs/zpl_super.c
index ecdbc36d81f8..3edacba462ee 100644
--- a/module/zfs/zpl_super.c
+++ b/module/zfs/zpl_super.c
@@ -184,35 +184,204 @@ zpl_statfs(struct dentry *dentry, struct kstatfs *statp)
 	return (error);
 }
 
+enum {
+	TOKEN_RO,
+	TOKEN_RW,
+	TOKEN_SETUID,
+	TOKEN_NOSETUID,
+	TOKEN_EXEC,
+	TOKEN_NOEXEC,
+	TOKEN_DEVICES,
+	TOKEN_NODEVICES,
+	TOKEN_XATTR,
+	TOKEN_NOXATTR,
+	TOKEN_ATIME,
+	TOKEN_NOATIME,
+	TOKEN_RELATIME,
+	TOKEN_NORELATIME,
+	TOKEN_NBMAND,
+	TOKEN_NONBMAND,
+	TOKEN_MNTPOINT,
+	TOKEN_LAST,
+};
+
+static const match_table_t zpl_tokens = {
+	{ TOKEN_RO,		MNTOPT_RO },
+	{ TOKEN_RW,		MNTOPT_RW },
+	{ TOKEN_SETUID,		MNTOPT_SETUID },
+	{ TOKEN_NOSETUID,	MNTOPT_NOSETUID },
+	{ TOKEN_EXEC,		MNTOPT_EXEC },
+	{ TOKEN_NOEXEC,		MNTOPT_NOEXEC },
+	{ TOKEN_DEVICES,	MNTOPT_DEVICES },
+	{ TOKEN_NODEVICES,	MNTOPT_NODEVICES },
+	{ TOKEN_XATTR,		MNTOPT_XATTR },
+	{ TOKEN_NOXATTR,	MNTOPT_NOXATTR },
+	{ TOKEN_ATIME,		MNTOPT_ATIME },
+	{ TOKEN_NOATIME,	MNTOPT_NOATIME },
+	{ TOKEN_RELATIME,	MNTOPT_RELATIME },
+	{ TOKEN_NORELATIME,	MNTOPT_NORELATIME },
+	{ TOKEN_NBMAND,		MNTOPT_NBMAND },
+	{ TOKEN_NONBMAND,	MNTOPT_NONBMAND },
+	{ TOKEN_MNTPOINT,	MNTOPT_MNTPOINT "=%s" },
+	{ TOKEN_LAST,		NULL },
+};
+
+static int
+zpl_parse_option(char *option, int token, substring_t *args,
+    zfs_mntopts_t *zmo, boolean_t isremount)
+{
+	switch (token) {
+	case TOKEN_RO:
+		zmo->z_readonly = B_TRUE;
+		zmo->z_do_readonly = B_TRUE;
+		break;
+	case TOKEN_RW:
+		zmo->z_readonly = B_FALSE;
+		zmo->z_do_readonly = B_TRUE;
+		break;
+	case TOKEN_SETUID:
+		zmo->z_setuid = B_TRUE;
+		zmo->z_do_setuid = B_TRUE;
+		break;
+	case TOKEN_NOSETUID:
+		zmo->z_setuid = B_FALSE;
+		zmo->z_do_setuid = B_TRUE;
+		break;
+	case TOKEN_EXEC:
+		zmo->z_exec = B_TRUE;
+		zmo->z_do_exec = B_TRUE;
+		break;
+	case TOKEN_NOEXEC:
+		zmo->z_exec = B_FALSE;
+		zmo->z_do_exec = B_TRUE;
+		break;
+	case TOKEN_DEVICES:
+		zmo->z_devices = B_TRUE;
+		zmo->z_do_devices = B_TRUE;
+		break;
+	case TOKEN_NODEVICES:
+		zmo->z_devices = B_FALSE;
+		zmo->z_do_devices = B_TRUE;
+		break;
+	case TOKEN_XATTR:
+		zmo->z_xattr = B_TRUE;
+		zmo->z_do_xattr = B_TRUE;
+		break;
+	case TOKEN_NOXATTR:
+		zmo->z_xattr = B_FALSE;
+		zmo->z_do_xattr = B_TRUE;
+		break;
+	case TOKEN_ATIME:
+		zmo->z_atime = B_TRUE;
+		zmo->z_do_atime = B_TRUE;
+		break;
+	case TOKEN_NOATIME:
+		zmo->z_atime = B_FALSE;
+		zmo->z_do_atime = B_TRUE;
+		break;
+	case TOKEN_RELATIME:
+		zmo->z_relatime = B_TRUE;
+		zmo->z_do_relatime = B_TRUE;
+		break;
+	case TOKEN_NORELATIME:
+		zmo->z_relatime = B_FALSE;
+		zmo->z_do_relatime = B_TRUE;
+		break;
+	case TOKEN_NBMAND:
+		zmo->z_nbmand = B_TRUE;
+		zmo->z_do_nbmand = B_TRUE;
+		break;
+	case TOKEN_NONBMAND:
+		zmo->z_nbmand = B_FALSE;
+		zmo->z_do_nbmand = B_TRUE;
+		break;
+	case TOKEN_MNTPOINT:
+		zmo->z_mntpoint = match_strdup(&args[0]);
+		if (zmo->z_mntpoint == NULL)
+			return (-ENOMEM);
+
+		break;
+	default:
+		break;
+	}
+
+	return (0);
+}
+
+/*
+ * Parse the mntopts string storing the results in provided zmo argument.
+ * If an error occurs the zmo argument will not be modified.  The caller
+ * needs to set isremount when recycling an existing zfs_mntopts_t.
+ */
+static int
+zpl_parse_options(char *osname, char *mntopts, zfs_mntopts_t *zmo,
+    boolean_t isremount)
+{
+	zfs_mntopts_t *tmp_zmo;
+	substring_t args[MAX_OPT_ARGS];
+	char *tmp_mntopts, *p;
+	int error, token;
+
+	if (mntopts == NULL)
+		return (-EINVAL);
+
+	tmp_zmo = zfs_mntopts_alloc();
+	tmp_zmo->z_osname = strdup(osname);
+	tmp_mntopts = strdup(mntopts);
+
+	while ((p = strsep(&tmp_mntopts, ",")) != NULL) {
+		if (!*p)
+			continue;
+
+		args[0].to = args[0].from = NULL;
+		token = match_token(p, zpl_tokens, args);
+		error = zpl_parse_option(p, token, args, tmp_zmo, isremount);
+		if (error) {
+			zfs_mntopts_free(tmp_zmo);
+			strfree(tmp_mntopts);
+			return (error);
+		}
+	}
+
+	strfree(tmp_mntopts);
+
+	if (isremount == B_TRUE) {
+		if (zmo->z_osname)
+			strfree(zmo->z_osname);
+
+		if (zmo->z_mntpoint)
+			strfree(zmo->z_mntpoint);
+	} else {
+		ASSERT3P(zmo->z_osname, ==, NULL);
+		ASSERT3P(zmo->z_mntpoint, ==, NULL);
+	}
+
+	memcpy(zmo, tmp_zmo, sizeof (zfs_mntopts_t));
+	kmem_free(tmp_zmo, sizeof (zfs_mntopts_t));
+
+	return (0);
+}
+
 static int
 zpl_remount_fs(struct super_block *sb, int *flags, char *data)
 {
+	zfs_sb_t *zsb = sb->s_fs_info;
 	fstrans_cookie_t cookie;
 	int error;
 
+	error = zpl_parse_options(zsb->z_mntopts->z_osname, data,
+	    zsb->z_mntopts, B_TRUE);
+	if (error)
+		return (error);
+
 	cookie = spl_fstrans_mark();
-	error = -zfs_remount(sb, flags, data);
+	error = -zfs_remount(sb, flags, zsb->z_mntopts);
 	spl_fstrans_unmark(cookie);
 	ASSERT3S(error, <=, 0);
 
 	return (error);
 }
 
-/*
- * ZFS specific features must be explicitly handled here, the VFS will
- * automatically handled the following generic functionality.
- *
- *   MNT_NOSUID,
- *   MNT_NODEV,
- *   MNT_NOEXEC,
- *   MNT_NOATIME,
- *   MNT_NODIRATIME,
- *   MNT_READONLY,
- *   MNT_STRICTATIME,
- *   MS_SYNCHRONOUS,
- *   MS_DIRSYNC,
- *   MS_MANDLOCK.
- */
 static int
 __zpl_show_options(struct seq_file *seq, zfs_sb_t *zsb)
 {
@@ -249,11 +418,12 @@ zpl_show_options(struct seq_file *seq, struct vfsmount *vfsp)
 static int
 zpl_fill_super(struct super_block *sb, void *data, int silent)
 {
+	zfs_mntopts_t *zmo = (zfs_mntopts_t *)data;
 	fstrans_cookie_t cookie;
 	int error;
 
 	cookie = spl_fstrans_mark();
-	error = -zfs_domount(sb, data, silent);
+	error = -zfs_domount(sb, zmo, silent);
 	spl_fstrans_unmark(cookie);
 	ASSERT3S(error, <=, 0);
 
@@ -265,18 +435,32 @@ static struct dentry *
 zpl_mount(struct file_system_type *fs_type, int flags,
     const char *osname, void *data)
 {
-	zpl_mount_data_t zmd = { osname, data };
+	zfs_mntopts_t *zmo = zfs_mntopts_alloc();
+	int error;
+
+	error = zpl_parse_options((char *)osname, (char *)data, zmo, B_FALSE);
+	if (error) {
+		zfs_mntopts_free(zmo);
+		return (ERR_PTR(error));
+	}
 
-	return (mount_nodev(fs_type, flags, &zmd, zpl_fill_super));
+	return (mount_nodev(fs_type, flags, zmo, zpl_fill_super));
 }
 #else
 static int
 zpl_get_sb(struct file_system_type *fs_type, int flags,
     const char *osname, void *data, struct vfsmount *mnt)
 {
-	zpl_mount_data_t zmd = { osname, data };
+	zfs_mntopts_t *zmo = zfs_mntopts_alloc();
+	int error;
+
+	error = zpl_parse_options((char *)osname, (char *)data, zmo, B_FALSE);
+	if (error) {
+		zfs_mntopts_free(zmo);
+		return (error);
+	}
 
-	return (get_sb_nodev(fs_type, flags, &zmd, zpl_fill_super, mnt));
+	return (get_sb_nodev(fs_type, flags, zmo, zpl_fill_super, mnt));
 }
 #endif /* HAVE_MOUNT_NODEV */