[PATCH] md: allow array level to be set textually via sysfs

Signed-off-by: Neil Brown <neilb@suse.de>
Acked-by: Greg KH <greg@kroah.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

11 files changed, 67 insertions, 14 deletions

diff --git a/Documentation/md.txt b/Documentation/md.txt
index c5512afd5917..fd43fd2cad2f 100644
--- a/Documentation/md.txt
+++ b/Documentation/md.txt
@@ -189,6 +189,14 @@ All md devices contain:
      1.2 (newer format in varying locations) or "none" indicating that
      the kernel isn't managing metadata at all.
 
+  level
+     The raid 'level' for this array.  The name will often (but not
+     always) be the same as the name of the module that implements the
+     level.  To be auto-loaded the module must have an alias
+        md-$LEVEL  e.g. md-raid5
+     This can be written only while the array is being assembled, not
+     after it is started.
+
 As component devices are added to an md array, they appear in the 'md'
 directory as new directories named
       dev-XXX
diff --git a/drivers/md/faulty.c b/drivers/md/faulty.c
index f12e83086897..a7a5ab554338 100644
--- a/drivers/md/faulty.c
+++ b/drivers/md/faulty.c
@@ -342,4 +342,5 @@ module_init(raid_init);
 module_exit(raid_exit);
 MODULE_LICENSE("GPL");
 MODULE_ALIAS("md-personality-10"); /* faulty */
+MODULE_ALIAS("md-faulty");
 MODULE_ALIAS("md-level--5");
diff --git a/drivers/md/linear.c b/drivers/md/linear.c
index 79dee8159217..777585458c85 100644
--- a/drivers/md/linear.c
+++ b/drivers/md/linear.c
@@ -376,5 +376,6 @@ static void linear_exit (void)
 module_init(linear_init);
 module_exit(linear_exit);
 MODULE_LICENSE("GPL");
-MODULE_ALIAS("md-personality-1"); /* LINEAR - degrecated*/
+MODULE_ALIAS("md-personality-1"); /* LINEAR - deprecated*/
+MODULE_ALIAS("md-linear");
 MODULE_ALIAS("md-level--1");
diff --git a/drivers/md/md.c b/drivers/md/md.c
index ecc0166ba779..594d8c312e6a 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -303,12 +303,15 @@ static mdk_rdev_t * find_rdev(mddev_t * mddev, dev_t dev)
         return NULL;
 }
 
-static struct mdk_personality *find_pers(int level)
+static struct mdk_personality *find_pers(int level, char *clevel)
 {
         struct mdk_personality *pers;
-        list_for_each_entry(pers, &pers_list, list)
-                if (pers->level == level)
+        list_for_each_entry(pers, &pers_list, list) {
+                if (level != LEVEL_NONE && pers->level == level)
                         return pers;
+                if (strcmp(pers->name, clevel)==0)
+                        return pers;
+        }
         return NULL;
 }
 
@@ -715,6 +718,7 @@ static int super_90_validate(mddev_t *mddev, mdk_rdev_t *rdev)
                 mddev->ctime = sb->ctime;
                 mddev->utime = sb->utime;
                 mddev->level = sb->level;
+                mddev->clevel[0] = 0;
                 mddev->layout = sb->layout;
                 mddev->raid_disks = sb->raid_disks;
                 mddev->size = sb->size;
@@ -1051,6 +1055,7 @@ static int super_1_validate(mddev_t *mddev, mdk_rdev_t *rdev)
                 mddev->ctime = le64_to_cpu(sb->ctime) & ((1ULL << 32)-1);
                 mddev->utime = le64_to_cpu(sb->utime) & ((1ULL << 32)-1);
                 mddev->level = le32_to_cpu(sb->level);
+                mddev->clevel[0] = 0;
                 mddev->layout = le32_to_cpu(sb->layout);
                 mddev->raid_disks = le32_to_cpu(sb->raid_disks);
                 mddev->size = le64_to_cpu(sb->size)/2;
@@ -1774,15 +1779,36 @@ static ssize_t
 level_show(mddev_t *mddev, char *page)
 {
         struct mdk_personality *p = mddev->pers;
-        if (p == NULL && mddev->raid_disks == 0)
-                return 0;
-        if (mddev->level >= 0)
-                return sprintf(page, "raid%d\n", mddev->level);
-        else
+        if (p)
                 return sprintf(page, "%s\n", p->name);
+        else if (mddev->clevel[0])
+                return sprintf(page, "%s\n", mddev->clevel);
+        else if (mddev->level != LEVEL_NONE)
+                return sprintf(page, "%d\n", mddev->level);
+        else
+                return 0;
+}
+
+static ssize_t
+level_store(mddev_t *mddev, const char *buf, size_t len)
+{
+        int rv = len;
+        if (mddev->pers)
+                return -EBUSY;
+        if (len == 0)
+                return 0;
+        if (len >= sizeof(mddev->clevel))
+                return -ENOSPC;
+        strncpy(mddev->clevel, buf, len);
+        if (mddev->clevel[len-1] == '\n')
+                len--;
+        mddev->clevel[len] = 0;
+        mddev->level = LEVEL_NONE;
+        return rv;
 }
 
-static struct md_sysfs_entry md_level = __ATTR_RO(level);
+static struct md_sysfs_entry md_level =
+__ATTR(level, 0644, level_show, level_store);
 
 static ssize_t
 raid_disks_show(mddev_t *mddev, char *page)
@@ -2158,7 +2184,10 @@ static int do_md_run(mddev_t * mddev)
         }
 
 #ifdef CONFIG_KMOD
-        request_module("md-level-%d", mddev->level);
+        if (mddev->level != LEVEL_NONE)
+                request_module("md-level-%d", mddev->level);
+        else if (mddev->clevel[0])
+                request_module("md-%s", mddev->clevel);
 #endif
 
         /*
@@ -2180,15 +2209,21 @@ static int do_md_run(mddev_t * mddev)
                 return -ENOMEM;
 
         spin_lock(&pers_lock);
-        pers = find_pers(mddev->level);
+        pers = find_pers(mddev->level, mddev->clevel);
         if (!pers || !try_module_get(pers->owner)) {
                 spin_unlock(&pers_lock);
-                printk(KERN_WARNING "md: personality for level %d is not loaded!\n",
-                       mddev->level);
+                if (mddev->level != LEVEL_NONE)
+                        printk(KERN_WARNING "md: personality for level %d is not loaded!\n",
+                               mddev->level);
+                else
+                        printk(KERN_WARNING "md: personality for level %s is not loaded!\n",
+                               mddev->clevel);
                 return -EINVAL;
         }
         mddev->pers = pers;
         spin_unlock(&pers_lock);
+        mddev->level = pers->level;
+        strlcpy(mddev->clevel, pers->name, sizeof(mddev->clevel));
 
         mddev->recovery = 0;
         mddev->resync_max_sectors = mddev->size << 1; /* may be over-ridden by personality */
diff --git a/drivers/md/multipath.c b/drivers/md/multipath.c
index d4d838e3f9f8..e6aa309a66d7 100644
--- a/drivers/md/multipath.c
+++ b/drivers/md/multipath.c
@@ -578,4 +578,5 @@ module_init(multipath_init);
 module_exit(multipath_exit);
 MODULE_LICENSE("GPL");
 MODULE_ALIAS("md-personality-7"); /* MULTIPATH */
+MODULE_ALIAS("md-multipath");
 MODULE_ALIAS("md-level--4");
diff --git a/drivers/md/raid0.c b/drivers/md/raid0.c
index 7fb69e29391b..abbca150202b 100644
--- a/drivers/md/raid0.c
+++ b/drivers/md/raid0.c
@@ -536,4 +536,5 @@ module_init(raid0_init);
 module_exit(raid0_exit);
 MODULE_LICENSE("GPL");
 MODULE_ALIAS("md-personality-2"); /* RAID0 */
+MODULE_ALIAS("md-raid0");
 MODULE_ALIAS("md-level-0");
diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c
index 7d4465f93064..181c9616d5f1 100644
--- a/drivers/md/raid1.c
+++ b/drivers/md/raid1.c
@@ -2092,4 +2092,5 @@ module_init(raid_init);
 module_exit(raid_exit);
 MODULE_LICENSE("GPL");
 MODULE_ALIAS("md-personality-3"); /* RAID1 */
+MODULE_ALIAS("md-raid1");
 MODULE_ALIAS("md-level-1");
diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
index 8e6f6dfddb2b..201dc7168a5f 100644
--- a/drivers/md/raid10.c
+++ b/drivers/md/raid10.c
@@ -2117,4 +2117,5 @@ module_init(raid_init);
 module_exit(raid_exit);
 MODULE_LICENSE("GPL");
 MODULE_ALIAS("md-personality-9"); /* RAID10 */
+MODULE_ALIAS("md-raid10");
 MODULE_ALIAS("md-level-10");
diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index b0cfd3ca9ca0..9cc844f455bf 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -2240,5 +2240,7 @@ module_init(raid5_init);
 module_exit(raid5_exit);
 MODULE_LICENSE("GPL");
 MODULE_ALIAS("md-personality-4"); /* RAID5 */
+MODULE_ALIAS("md-raid5");
+MODULE_ALIAS("md-raid4");
 MODULE_ALIAS("md-level-5");
 MODULE_ALIAS("md-level-4");
diff --git a/drivers/md/raid6main.c b/drivers/md/raid6main.c
index 06b32bd671a3..84dd875bb2f6 100644
--- a/drivers/md/raid6main.c
+++ b/drivers/md/raid6main.c
@@ -2341,4 +2341,5 @@ module_init(raid6_init);
 module_exit(raid6_exit);
 MODULE_LICENSE("GPL");
 MODULE_ALIAS("md-personality-8"); /* RAID6 */
+MODULE_ALIAS("md-raid6");
 MODULE_ALIAS("md-level-6");
diff --git a/include/linux/raid/md_k.h b/include/linux/raid/md_k.h
index 0fb5af6d622d..686463115438 100644
--- a/include/linux/raid/md_k.h
+++ b/include/linux/raid/md_k.h
@@ -119,6 +119,7 @@ struct mddev_s
         int                             chunk_size;
         time_t                          ctime, utime;
         int                             level, layout;
+        char                            clevel[16];
         int                             raid_disks;
         int                             max_disks;
         sector_t                        size; /* used size of component devices */