Default to --auto=yes

so the array devices with 'standard' names
get created automatically, as this is almost always what is wanted.

ChangeLog

@@ -8,6 +8,8 @@ Changes Prior to this release
 	missing devices.
     -   Support --update=devicesize for cases where the underlying device
 	can change size.
+    -   Default to --auto=yes so the array devices with 'standard' names
+	get created automatically, as this is almost always what is wanted.
 
 Changes Prior to 2.5.6 release
     -   Fix bug which meant "bitmap=xxx" in mdadm.conf was not handled

config.c

@@ -255,6 +255,7 @@ mddev_dev_t load_partitions(void)
 }
 
 struct createinfo createinfo = {
+	.autof = 2, /* by default, create devices with standard names */
 	.symlinks = 1,
 #ifdef DEBIAN
 	.gid = 6, /* disk */

mdadm.8

@@ -573,6 +573,10 @@ from this.  See DEVICE NAMES below.
 The argument can also come immediately after
 "-a".  e.g. "-ap".
 
+If --auto is not given on the command line or in the config file, then
+the default will be
+.BR --auto=yes .
+
 If
 .I --scan
 is also given, then any
@@ -1060,13 +1064,11 @@ may work for RAID1, 4, 5, 6, or 10), give the
 .B --run
 flag.
 
-If an
-.B auto
-option is given, either on the command line (--auto) or in the
-configuration file (e.g. auto=part), then
-.I mdadm
-will create the md device if necessary or will re-create it if it
-doesn't look usable as it is.
+If the md device does not exist, then it will be created providing the
+intent is clear. i.e. the name must be in a standard form, or the
+.I --auto
+option must be given to clarify how and whether the device should be
+created.
 
 This can be useful for handling partitioned devices (which don't have
 a stable device number - it can change after a reboot) and when using

mdopen.c

@@ -135,10 +135,6 @@ int open_mddev(char *dev, int autof)
 				dev);
 			return -1;
 		}
-		if (autof == 2 && stb.st_mode == 0 && !is_standard(dev, NULL)) {
-			fprintf(stderr, Name ": --auto=yes requires a 'standard' md device name, not %s\n", dev);
-			return -1;
-		}
 		/* check major number is correct */
 		num = -1;
 		std = is_standard(dev, &num);
@@ -146,19 +142,23 @@ int open_mddev(char *dev, int autof)
 		switch(autof) {
 		case 2: /* only create is_standard names */
 			if (!std && !stb.st_mode) {
-				fprintf(stderr, Name ": --auto=yes requires a 'standard' md device name, not %s\n", dev);
+				fprintf(stderr, Name
+			": %s does not exist and is not a 'standard' name "
+			"so it cannot be created\n", dev);
 				return -1;
 			}
 			break;
 		case 3: /* create md, reject std>0 */
 			if (std > 0) {
-				fprintf(stderr, Name ": that --auto option not compatable with device named %s\n", dev);
+				fprintf(stderr, Name ": that --auto option "
+				"not compatable with device named %s\n", dev);
 				return -1;
 			}
 			break;
 		case 4: /* create mdp, reject std<0 */
 			if (std < 0) {
-				fprintf(stderr, Name ": that --auto option not compatable with device named %s\n", dev);
+				fprintf(stderr, Name ": that --auto option "
+				"not compatable with device named %s\n", dev);
 				return -1;
 			}
 			break;