Add more specific subcommand usage messages

The device, data, fs, and subvolume subcommands currently print out a
generic usage message. Make these more specific.

Signed-off-by: Brett Holman <bholman.devel@gmail.com>

bcachefs.c

@@ -92,14 +92,9 @@ static char *full_cmd;
 
 static char *pop_cmd(int *argc, char *argv[])
 {
-	if (*argc < 2) {
-		printf("%s: missing command\n", argv[0]);
-		usage();
-		exit(EXIT_FAILURE);
-	}
-
 	char *cmd = argv[1];
-	memmove(&argv[1], &argv[2], *argc * sizeof(argv[0]));
+	if (!(*argc < 2))
+		memmove(&argv[1], &argv[2], *argc * sizeof(argv[0]));
 	(*argc)--;
 
 	full_cmd = mprintf("%s %s", full_cmd, cmd);
@@ -110,10 +105,11 @@ static int fs_cmds(int argc, char *argv[])
 {
 	char *cmd = pop_cmd(&argc, argv);
 
+	if (argc < 2)
+		return fs_usage();
 	if (!strcmp(cmd, "usage"))
 		return cmd_fs_usage(argc, argv);
 
-	usage();
 	return 0;
 }
 
@@ -121,6 +117,8 @@ static int device_cmds(int argc, char *argv[])
 {
 	char *cmd = pop_cmd(&argc, argv);
 
+	if (argc < 2)
+		return device_usage();
 	if (!strcmp(cmd, "add"))
 		return cmd_device_add(argc, argv);
 	if (!strcmp(cmd, "remove"))
@@ -138,7 +136,6 @@ static int device_cmds(int argc, char *argv[])
 	if (!strcmp(cmd, "resize-journal"))
 		return cmd_device_resize_journal(argc, argv);
 
-	usage();
 	return 0;
 }
 
@@ -146,19 +143,21 @@ static int data_cmds(int argc, char *argv[])
 {
 	char *cmd = pop_cmd(&argc, argv);
 
+	if (argc < 2)
+		return data_usage();
 	if (!strcmp(cmd, "rereplicate"))
 		return cmd_data_rereplicate(argc, argv);
 	if (!strcmp(cmd, "job"))
 		return cmd_data_job(argc, argv);
 
-	usage();
 	return 0;
 }
 
 static int subvolume_cmds(int argc, char *argv[])
 {
 	char *cmd = pop_cmd(&argc, argv);
-
+	if (argc < 2)
+		return subvolume_usage();
 	if (!strcmp(cmd, "create"))
 		return cmd_subvolume_create(argc, argv);
 	if (!strcmp(cmd, "delete"))
@@ -166,7 +165,6 @@ static int subvolume_cmds(int argc, char *argv[])
 	if (!strcmp(cmd, "snapshot"))
 		return cmd_subvolume_snapshot(argc, argv);
 
-	usage();
 	return 0;
 }
 
@@ -179,16 +177,36 @@ int main(int argc, char *argv[])
 	setvbuf(stdout, NULL, _IOLBF, 0);
 
 	char *cmd = pop_cmd(&argc, argv);
+	if (argc < 1) {
+		puts("missing command\n");
+		goto usage;
+	}
+
+	/* these subcommands display usage when argc < 2 */
+	if (!strcmp(cmd, "device"))
+		return device_cmds(argc, argv);
+	if (!strcmp(cmd, "fs"))
+		return fs_cmds(argc, argv);
+	if (!strcmp(cmd, "data"))
+		return data_cmds(argc, argv);
+	if (!strcmp(cmd, "subvolume"))
+		return subvolume_cmds(argc, argv);
+	if (!strcmp(cmd, "format"))
+		return cmd_format(argc, argv);
+	if (!strcmp(cmd, "fsck"))
+		return cmd_fsck(argc, argv);
+
+	if (argc < 2) {
+		printf("%s: missing command\n", argv[0]);
+		usage();
+		exit(EXIT_FAILURE);
+	}
 
 	if (!strcmp(cmd, "version"))
 		return cmd_version(argc, argv);
-	if (!strcmp(cmd, "format"))
-		return cmd_format(argc, argv);
 	if (!strcmp(cmd, "show-super"))
 		return cmd_show_super(argc, argv);
 
-	if (!strcmp(cmd, "fsck"))
-		return cmd_fsck(argc, argv);
 
 #if 0
 	if (!strcmp(cmd, "assemble"))
@@ -201,17 +219,6 @@ int main(int argc, char *argv[])
 		return cmd_stop(argc, argv);
 #endif
 
-	if (!strcmp(cmd, "fs"))
-		return fs_cmds(argc, argv);
-
-	if (!strcmp(cmd, "device"))
-		return device_cmds(argc, argv);
-
-	if (!strcmp(cmd, "data"))
-		return data_cmds(argc, argv);
-	if (!strcmp(cmd, "subvolume"))
-		return subvolume_cmds(argc, argv);
-
 	if (!strcmp(cmd, "unlock"))
 		return cmd_unlock(argc, argv);
 	if (!strcmp(cmd, "set-passphrase"))
@@ -245,6 +252,7 @@ int main(int argc, char *argv[])
 	}
 
 	printf("Unknown command %s\n", cmd);
+usage:
 	usage();
 	exit(EXIT_FAILURE);
 }

cmd_data.c

@@ -9,6 +9,19 @@
 #include "cmds.h"
 #include "libbcachefs.h"
 
+int data_usage(void)
+{
+	puts("bcachefs data - manage filesystem data\n"
+	     "Usage: bcachefs data <CMD> [OPTIONS]\n"
+	     "\n"
+	     "Commands:\n"
+	     "  rereplicate                     Rereplicate degraded data\n"
+	     "  job                             Kick off low level data jobs\n"
+	     "\n"
+	     "Report bugs to <linux-bcache@vger.kernel.org>");
+	return 0;
+}
+
 static void data_rereplicate_usage(void)
 {
 	puts("bcachefs data rereplicate\n"

cmd_device.c

@@ -21,6 +21,25 @@
 #include "libbcachefs/opts.h"
 #include "tools-util.h"
 
+int device_usage(void)
+{
+       puts("bcachefs device - manage devices within a running filesystem\n"
+            "Usage: bcachefs device <CMD> [OPTION]\n"
+            "\n"
+            "Commands:\n"
+            "  add                     add a new device to an existing filesystem\n"
+            "  remove                  remove a device from an existing filesystem\n"
+            "  online                  re-add an existing member to a filesystem\n"
+            "  offline                 take a device offline, without removing it\n"
+            "  evacuate                migrate data off a specific device\n"
+            "  set-state               mark a device as failed\n"
+            "  resize                  resize filesystem on a device\n"
+            "  resize-journal          resize journal on a device\n"
+            "\n"
+            "Report bugs to <linux-bcachefs@vger.kernel.org>");
+       return 0;
+}
+
 static void device_add_usage(void)
 {
 	puts("bcachefs device add - add a device to an existing filesystem\n"

cmd_fs.c

@@ -195,6 +195,18 @@ static void print_fs_usage(const char *path, enum units units)
 	bcache_fs_close(fs);
 }
 
+int fs_usage(void)
+{
+       puts("bcachefs fs - manage a running filesystem\n"
+            "Usage: bcachefs fs <CMD> [OPTION]... path\n"
+            "\n"
+            "Commands:\n"
+            "  usage                      show disk usage\n"
+            "\n"
+            "Report bugs to <linux-bcachefs@vger.kernel.org>");
+       return 0;
+}
+
 int cmd_fs_usage(int argc, char *argv[])
 {
 	enum units units = BYTES;

cmd_subvolume.c

@@ -19,6 +19,20 @@
 #include "libbcachefs/opts.h"
 #include "tools-util.h"
 
+int subvolume_usage(void)
+{
+	puts("bcachefs subvolume - manage subvolumes and snapshots\n"
+	     "Usage: bcachefs subvolume <CMD> [OPTION]\n"
+	     "\n"
+	     "Commands:\n"
+	     "  create                  create a subvolume\n"
+	     "  delete                  delete a subvolume\n"
+	     "  snapshot                create a snapshot\n"
+	     "\n"
+	     "Report bugs to <linux-bcachefs@vger.kernel.org>");
+	return 0;
+}
+
 static void subvolume_create_usage(void)
 {
 	puts("bcachefs subvolume create - create a new subvolume\n"

cmds.h

@@ -19,8 +19,10 @@ int cmd_run(int argc, char *argv[]);
 int cmd_stop(int argc, char *argv[]);
 #endif
 
+int fs_usage(void);
 int cmd_fs_usage(int argc, char *argv[]);
 
+int device_usage(void);
 int cmd_device_add(int argc, char *argv[]);
 int cmd_device_remove(int argc, char *argv[]);
 int cmd_device_online(int argc, char *argv[]);
@@ -30,6 +32,7 @@ int cmd_device_set_state(int argc, char *argv[]);
 int cmd_device_resize(int argc, char *argv[]);
 int cmd_device_resize_journal(int argc, char *argv[]);
 
+int data_usage(void);
 int cmd_data_rereplicate(int argc, char *argv[]);
 int cmd_data_job(int argc, char *argv[]);
 
@@ -50,6 +53,7 @@ int cmd_version(int argc, char *argv[]);
 
 int cmd_setattr(int argc, char *argv[]);
 
+int subvolume_usage(void);
 int cmd_subvolume_create(int argc, char *argv[]);
 int cmd_subvolume_delete(int argc, char *argv[]);
 int cmd_subvolume_snapshot(int argc, char *argv[]);