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>

1 files changed, 4 insertions, 3 deletions

diff --git a/drivers/md/md.c b/drivers/md/md.c
index 39757566f39b..08e0f8d672c3 100644
--- 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;
         }