create_mddev: add support for /dev/md_XXX non-numeric names.

With the 'devnm' infrastructure fixed, it is quite easy to support
names like "md_home" for md arrays.
The currently defaults to "off" and can be enabled in mdadm.conf with
  CREATE names=yes
This is incase other tools get confused by the new names.

Signed-off-by: NeilBrown <neilb@suse.de>

diff --git a/Create.c b/Create.c
index 63d50d67670a6fb5614b8ca227d02a62a444aa23..e7ed09b40254b8cac985d38ca42c752b2158440b 100644 (file)
--- a/Create.c
+++ b/Create.c
@@ -687,6 +687,7 @@ int Create(struct supertype *st, char *mddev,
                /* base name on mddev */
                /*  /dev/md0 -> 0
                 *  /dev/md_d0 -> d0
+                *  /dev/md_foo -> foo
                 *  /dev/md/1 -> 1
                 *  /dev/md/d1 -> d1
                 *  /dev/md/home -> home
@@ -696,9 +697,8 @@ int Create(struct supertype *st, char *mddev,
                name = strrchr(mddev, '/');
                if (name) {
                        name++;
-                       if (strncmp(name, "md_d", 4)==0 &&
-                           strlen(name) > 4 &&
-                           isdigit(name[4]) &&
+                       if (strncmp(name, "md_", 3)==0 &&
+                           strlen(name) > 3 &&
                            (name-mddev) == 5 /* /dev/ */)
                                name += 3;
                        else if (strncmp(name, "md", 2)==0 &&

diff --git a/config.c b/config.c
index 798338fbda663df06f717115aa75617d66f09eb6..189714a8855e23fad2de42c8e2b37eb0f65ae15a 100644 (file)
--- a/config.c
+++ b/config.c
@@ -219,6 +219,7 @@ struct mddev_dev *load_containers(void)
 struct createinfo createinfo = {
        .autof = 2, /* by default, create devices with standard names */
        .symlinks = 1,
+       .names = 0, /* By default, stick with numbered md devices. */
 #ifdef DEBIAN
        .gid = 6, /* disk */
        .mode = 0660,
@@ -334,6 +335,10 @@ static void createline(char *line)
                        createinfo.symlinks = 1;
                else if  (strncasecmp(w, "symlinks=no", 11) == 0)
                        createinfo.symlinks = 0;
+               else if (strncasecmp(w, "names=yes", 12) == 0)
+                       createinfo.names = 1;
+               else if  (strncasecmp(w, "names=no", 11) == 0)
+                       createinfo.names = 0;
                else {
                        pr_err("unrecognised word on CREATE line: %s\n",
                                w);

diff --git a/mdadm.8.in b/mdadm.8.in
index ef937816d1293dac7f855ebe53031e467d19897e..740edbaa0cf3fa7627b7e07016983ead1aa80322 100644 (file)
--- a/mdadm.8.in
+++ b/mdadm.8.in
@@ -2957,19 +2957,33 @@ exists or is listed in the config file.
 The standard names for non-partitioned arrays (the only sort of md
 array available in 2.4 and earlier) are of the form
 .IP
-/dev/mdNN
+.RB /dev/md NN
 .PP
 where NN is a number.
 The standard names for partitionable arrays (as available from 2.6
-onwards) are of the form
+onwards) are of the form:
 .IP
-/dev/md_dNN
+.RB /dev/md_d NN
 .PP
-Partition numbers should be indicated by added "pMM" to these, thus "/dev/md/d1p2".
+Partition numbers should be indicated by adding "pMM" to these, thus "/dev/md/d1p2".
 .PP
-From kernel version, 2.6.28 the "non-partitioned array" can actually
-be partitioned.  So the "md_dNN" names are no longer needed, and
-partitions such as "/dev/mdNNpXX" are possible.
+From kernel version 2.6.28 the "non-partitioned array" can actually
+be partitioned.  So the "md_d\fBNN\fP"
+names are no longer needed, and
+partitions such as "/dev/md\fBNN\fPp\fBXX\fp"
+are possible.
+.PP
+From kernel version 2.6.29 standard names can be non-numeric following
+the form:
+.IP
+.RB /dev/md_ XXX
+.PP
+where
+.B XXX
+is any string.  These names are supported by
+.I mdadm
+since version 3.3 provided they are enabled in
+.IR mdadm.conf .
 
 .SH NOTE
 .I mdadm

diff --git a/mdadm.conf.5 b/mdadm.conf.5
index 4ff0a24378c9f1a361d16fe42992fba6decd4c0a..1f01648db580868ecac57ffcfa924227c1d035e5 100644 (file)
--- a/mdadm.conf.5
+++ b/mdadm.conf.5
@@ -148,7 +148,7 @@ created as /dev/mdX, then the minor number X is stored.
 The value is a comma separated list of device names or device name
 patterns.
 Only devices with names which match one entry in the list will be used
-to assemble the array.  Note that the devices 
+to assemble the array.  Note that the devices
 listed there must also be listed on a DEVICE line.
 .TP
 .B level=
@@ -339,6 +339,32 @@ or
 Give
 .B symlinks=no
 to suppress this symlink creation.
+
+.TP
+.B names=yes
+Since Linux 2.6.29 it has been possible to create
+.B md
+devices with a name like
+.B md_home
+rather than just a number, like
+.BR md3 .
+.I mdadm
+will use the numeric alternative by default as other tools that interact
+with md arrays may expect only numbers.
+If
+.B names=yes
+is given in
+.I mdadm.conf
+then
+.I mdadm
+will use a name when appropriate.
+If
+.B names=no
+is given, then non-numeric
+.I md
+device names will not be used even if the default changes in a future
+release of
+.IR mdadm .
 .RE
 
 .TP
@@ -437,7 +463,7 @@ The known metadata types are
 
 .TP
 .B POLICY
-This is used to specify what automatic behavior is allowed on devices 
+This is used to specify what automatic behavior is allowed on devices
 newly appearing in the system and provides a way of marking spares that can
 be moved to other arrays as well as the migration domains.
 .I Domain
@@ -475,7 +501,7 @@ file glob matching anything from
 .B /dev/disk/by-path
 .TP
 .B type=
-either 
+either
 .B disk
 or
 .BR part .

diff --git a/mdadm.h b/mdadm.h
index c7b5183b0fc4441563de74947c44c443928864a7..3139259db6b3c151dd43628afe4dfebd163d1bbe 100644 (file)
--- a/mdadm.h
+++ b/mdadm.h
@@ -257,6 +257,7 @@ struct createinfo {
        int     autof;
        int     mode;
        int     symlinks;
+       int     names;
        struct supertype *supertype;
 };
 

diff --git a/mdopen.c b/mdopen.c
index 856b5c0404fc1017e4333cefd7f1941ed8631215..fc118840f15dd2790b9b5b2888f8ec0b2583e008 100644 (file)
--- a/mdopen.c
+++ b/mdopen.c
@@ -126,7 +126,7 @@ void make_parts(char *dev, int cnt)
  *
  * If udev is configured, we create a temporary device, open it, and
  * unlink it.
- * If not, we create the /dev/mdXX device, and is name is usable,
+ * If not, we create the /dev/mdXX device, and if name is usable,
  * /dev/md/name
  * In any case we return /dev/md/name or (if that isn't available)
  * /dev/mdXX in 'chosen'.
@@ -260,25 +260,6 @@ int create_mddev(char *dev, char *name, int autof, int trustworthy,
                }
        }
 
-       if (num < 0) {
-               /* need to choose a free number. */
-               char *_devnm = find_free_devnm(use_mdp);
-               if (devnm == NULL) {
-                       pr_err("No avail md devices - aborting\n");
-                       return -1;
-               }
-               strcpy(devnm, _devnm);
-       } else {
-               sprintf(devnm, "%s%d", use_mdp?"md_d":"md", num);
-               if (mddev_busy(devnm)) {
-                       pr_err("%s is already in use.\n",
-                               dev);
-                       return -1;
-               }
-       }
-
-       sprintf(devname, "/dev/%s", devnm);
-
        if (cname[0] == 0 && name) {
                /* Need to find a name if we can
                 * We don't completely trust 'name'.  Truncate to
@@ -323,6 +304,40 @@ int create_mddev(char *dev, char *name, int autof, int trustworthy,
                }
        }
 
+       devnm[0] = 0;
+       if (num < 0 && cname && ci->names) {
+               int fd;
+               int n = -1;
+               sprintf(devnm, "md_%s", cname);
+               fd = open("/sys/module/md_mod/parameters/new_array", O_WRONLY);
+               if (fd >= 0) {
+                       n = write(fd, devnm, strlen(devnm));
+                       close(fd);
+               }
+               if (n < 0)
+                       devnm[0] = 0;
+       }
+       if (devnm[0])
+               ;
+       else if (num < 0) {
+               /* need to choose a free number. */
+               char *_devnm = find_free_devnm(use_mdp);
+               if (devnm == NULL) {
+                       pr_err("No avail md devices - aborting\n");
+                       return -1;
+               }
+               strcpy(devnm, _devnm);
+       } else {
+               sprintf(devnm, "%s%d", use_mdp?"md_d":"md", num);
+               if (mddev_busy(devnm)) {
+                       pr_err("%s is already in use.\n",
+                               dev);
+                       return -1;
+               }
+       }
+
+       sprintf(devname, "/dev/%s", devnm);
+
        if (dev && dev[0] == '/')
                strcpy(chosen, dev);
        else if (cname[0] == 0)