[PATCH] md: allow hot-adding devices to arrays with non-persistant superblocks.

It is possibly (and occasionally useful) to have a raid1 without persistent
superblocks.  The code in add_new_disk for adding a device to such an array
always tries to read a superblock.

This will obviously fail.

So do the appropriate test and call md_import_device with
appropriate args.

Signed-off-by: Neil Brown <neilb@cse.unsw.edu.au>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 5 insertions, 2 deletions

diff --git a/drivers/md/md.c b/drivers/md/md.c
index f1ac356e656d..866c704e008a 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -2226,8 +2226,11 @@ static int add_new_disk(mddev_t * mddev, mdu_disk_info_t *info)
                                mdname(mddev));
                         return -EINVAL;
                 }
-                rdev = md_import_device(dev, mddev->major_version,
-                                        mddev->minor_version);
+                if (mddev->persistent)
+                        rdev = md_import_device(dev, mddev->major_version,
+                                                mddev->minor_version);
+                else
+                        rdev = md_import_device(dev, -1, -1);
                 if (IS_ERR(rdev)) {
                         printk(KERN_WARNING 
                                 "md: md_import_device returned %ld\n",