md: allow an md array to appear with 0 drives if it has external metadata

Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/drivers/md/md.c b/drivers/md/md.c
index 39757566f39b996d884562cdbbda03dd68ee7175..08e0f8d672c3b712ee15e13d73f91c14e732f6c1 100644 (file)
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -4647,9 +4647,10 @@ static int md_ioctl(struct inode *inode, struct file *file,
         */
        /* if we are not initialised yet, only ADD_NEW_DISK, STOP_ARRAY,
         * RUN_ARRAY, and GET_ and SET_BITMAP_FILE are allowed */
-       if (!mddev->raid_disks && cmd != ADD_NEW_DISK && cmd != STOP_ARRAY
-                       && cmd != RUN_ARRAY && cmd != SET_BITMAP_FILE
-                       && cmd != GET_BITMAP_FILE) {
+       if ((!mddev->raid_disks && !mddev->external)
+           && cmd != ADD_NEW_DISK && cmd != STOP_ARRAY
+           && cmd != RUN_ARRAY && cmd != SET_BITMAP_FILE
+           && cmd != GET_BITMAP_FILE) {
                err = -ENODEV;
                goto abort_unlock;
        }