md/raid0: Ignore RAID0 layout if the second zone has only one device

commit ea23994edc4169bd90d7a9b5908c6ccefd82fa40 upstream.

The RAID0 layout is irrelevant if all members have the same size so the
array has only one zone. It is *also* irrelevant if the array has two
zones and the second zone has only one device, for example if the array
has two members of different sizes.

So in that case it makes sense to allow assembly even when the layout is
undefined, like what is done when the array has only one zone.

Reviewed-by: NeilBrown <neilb@suse.de>
Signed-off-by: Pascal Hambourg <pascal@plouf.fr.eu.org>
Signed-off-by: Song Liu <song@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/md/raid0.c b/drivers/md/raid0.c
index e179c121c03003a9aa4fbc1c8b423326a886b3a9..671d57c30690ae87a2039dca899ddf55938122f7 100644 (file)
--- a/drivers/md/raid0.c
+++ b/drivers/md/raid0.c
@@ -150,21 +150,6 @@ static int create_strip_zones(struct mddev *mddev, struct r0conf **private_conf)
        pr_debug("md/raid0:%s: FINAL %d zones\n",
                 mdname(mddev), conf->nr_strip_zones);
 
-       if (conf->nr_strip_zones == 1) {
-               conf->layout = RAID0_ORIG_LAYOUT;
-       } else if (mddev->layout == RAID0_ORIG_LAYOUT ||
-                  mddev->layout == RAID0_ALT_MULTIZONE_LAYOUT) {
-               conf->layout = mddev->layout;
-       } else if (default_layout == RAID0_ORIG_LAYOUT ||
-                  default_layout == RAID0_ALT_MULTIZONE_LAYOUT) {
-               conf->layout = default_layout;
-       } else {
-               pr_err("md/raid0:%s: cannot assemble multi-zone RAID0 with default_layout setting\n",
-                      mdname(mddev));
-               pr_err("md/raid0: please set raid0.default_layout to 1 or 2\n");
-               err = -ENOTSUPP;
-               goto abort;
-       }
        /*
         * now since we have the hard sector sizes, we can make sure
         * chunk size is a multiple of that sector size
@@ -293,6 +278,22 @@ static int create_strip_zones(struct mddev *mddev, struct r0conf **private_conf)
                         (unsigned long long)smallest->sectors);
        }
 
+       if (conf->nr_strip_zones == 1 || conf->strip_zone[1].nb_dev == 1) {
+               conf->layout = RAID0_ORIG_LAYOUT;
+       } else if (mddev->layout == RAID0_ORIG_LAYOUT ||
+                  mddev->layout == RAID0_ALT_MULTIZONE_LAYOUT) {
+               conf->layout = mddev->layout;
+       } else if (default_layout == RAID0_ORIG_LAYOUT ||
+                  default_layout == RAID0_ALT_MULTIZONE_LAYOUT) {
+               conf->layout = default_layout;
+       } else {
+               pr_err("md/raid0:%s: cannot assemble multi-zone RAID0 with default_layout setting\n",
+                      mdname(mddev));
+               pr_err("md/raid0: please set raid0.default_layout to 1 or 2\n");
+               err = -EOPNOTSUPP;
+               goto abort;
+       }
+
        pr_debug("md/raid0:%s: done.\n", mdname(mddev));
        *private_conf = conf;