zfs_main.c: cleanup initial implementation

- corrected `HELP_MOUNT` to more accurately reflect the options
- changed my usage of `dataset` to `filesystem` in order to align with documentation
- improved the recursive checks in `get_one_dataset()`
  - Skip any dataset with the canmount=off property
  - Skip any dataset whose name doesn't match the target filesystem or
  - Skip any dataset whose name doesn't contain the target filesystem + '/'
- corrected the `usage()` errors in `share_mount()` to accurately reflect the options
- limited the recursive feature to `zfs mount` only
- implemented a validity check of the specified target filesystem using `zfs_open()`

Signed-off-by: QORTEC <[email protected]>

cmd/zfs/zfs_main.c

@@ -307,7 +307,8 @@ get_usage(zfs_help_t idx)
 		    "[filesystem|volume|snapshot] ...\n"));
 	case HELP_MOUNT:
 		return (gettext("\tmount\n"
-		    "\tmount [-flvO] [-o opts] -r <-a | filesystem>\n"));
+		    "\tmount [-flvO] [-o opts] [-r filesystem] "
+			"<-a [filesystem] | filesystem>\n"));
 	case HELP_PROMOTE:
 		return (gettext("\tpromote <clone-filesystem>\n"));
 	case HELP_RECEIVE:
@@ -6731,7 +6732,7 @@ zfs_do_holds(int argc, char **argv)
 typedef struct get_all_state {
 	boolean_t	ga_verbose;
 	get_all_cb_t	*ga_cbp;
-	const char	*ga_dataset;
+	const char	*ga_filesystem;
 } get_all_state_t;
 
 static int
@@ -6772,12 +6773,31 @@ get_one_dataset(zfs_handle_t *zhp, void *data)
 	}
 
 	/*
-	 * Skip any dataset whos name doesn't have a prefix matching ga_dataset.
+	 * Check if ga_filesystem is set; used for recursive mounting
 	 */
-	if (state->ga_dataset != NULL && strncmp(zfs_get_name(zhp),
-	    state->ga_dataset, strlen(state->ga_dataset)) != 0) {
-		zfs_close(zhp);
-		return (0);
+	if (state->ga_filesystem != NULL) {
+		/*
+		 * Skip any dataset with the canmount=off property.
+		 */
+		if (zfs_prop_get_int(zhp, ZFS_PROP_CANMOUNT) == ZFS_CANMOUNT_OFF) {
+			zfs_close(zhp);
+			return (0);
+		}
+
+		/* Add a trailing / to ga_filesystem */
+		char filesystem[strlen(state->ga_filesystem) + 2];
+		strcpy(filesystem, state->ga_filesystem);
+		strcat(filesystem, "/");
+
+		/*
+		 * Skip any dataset whose name doesn't match ga_filesystem exactly
+		 * or have a prefix matching filesystem.
+		 */
+		if (!strcmp(zfs_get_name(zhp), state->ga_filesystem) == 0 ||
+		    !strncmp(zfs_get_name(zhp), filesystem, strlen(filesystem) == 0)) {
+			zfs_close(zhp);
+			return (0);
+		}
 	}
 
 	libzfs_add_handle(state->ga_cbp, zhp);
@@ -6787,12 +6807,12 @@ get_one_dataset(zfs_handle_t *zhp, void *data)
 }
 
 static void
-get_all_datasets(get_all_cb_t *cbp, boolean_t verbose, const char *dataset)
+get_all_datasets(get_all_cb_t *cbp, boolean_t verbose, const char *filesystem)
 {
 	get_all_state_t state = {
 	    .ga_verbose = verbose,
 	    .ga_cbp = cbp,
-	    .ga_dataset = dataset
+	    .ga_filesystem = filesystem
 	};
 
 	if (verbose)
@@ -6820,7 +6840,8 @@ typedef struct share_mount_state {
 	uint_t	sm_total; /* number of filesystems to process */
 	uint_t	sm_done; /* number of filesystems processed */
 	int	sm_status; /* -1 if any of the share/mount operations failed */
-	boolean_t	sm_explicit;
+	boolean_t	sm_explicit; /* true if filesystems were explictly requested,
+	    false if they are implied by `-a` */
 } share_mount_state_t;
 
 /*
@@ -7212,23 +7233,34 @@ share_mount(int op, int argc, char **argv)
 			argv++;
 		}
 
-		if (argc > 1) {
+		if (!recursive && argc > 1) {
 			(void) fprintf(stderr, gettext("usage: "
-			    "zfs mount -a <dataset>\n"));
+			    "zfs mount -a [filesystem]\n"));
 			usage(B_FALSE);
 		}
 
 		if (recursive && argc != 1) {
 			(void) fprintf(stderr, gettext("usage: "
-			    "zfs mount -r <dataset>\n"));
+			    "zfs mount -r <filesystem>\n"));
 			usage(B_FALSE);
 		}
 
-		const char *dataset = (argv[0] != NULL) ? argv[0] : NULL;
+		/*
+		 * Enable recursive -a for mounting only
+		 * Validate filesystem is actually a valid zfs filesystem
+		 */
+		const char *filesystem = NULL;
+		if (op == OP_MOUNT)
+			filesystem = argv[0];
+		if (filesystem != NULL &&
+		    zfs_open(g_zfs, filesystem, ZFS_TYPE_FILESYSTEM) == NULL) {
+			free(options);
+			return (1);
+		}
 
 		start_progress_timer();
 		get_all_cb_t cb = { 0 };
-		get_all_datasets(&cb, verbose, dataset);
+		get_all_datasets(&cb, verbose, filesystem);
 
 		if (cb.cb_used == 0) {
 			free(options);