[PATCH] md: fix raid10 assembly when too many devices are missing
If you try to assemble an array with too many missing devices, raid10 will now
reject the attempt, instead of allowing it.
Also check when hot-adding a drive and refuse the hot-add if the array is
beyond hope.
Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
index 5e0b333..834bf0f 100644
--- a/drivers/md/raid10.c
+++ b/drivers/md/raid10.c
@@ -906,6 +906,27 @@
conf->r10buf_pool = NULL;
}
+/* check if there are enough drives for
+ * every block to appear on atleast one
+ */
+static int enough(conf_t *conf)
+{
+ int first = 0;
+
+ do {
+ int n = conf->copies;
+ int cnt = 0;
+ while (n--) {
+ if (conf->mirrors[first].rdev)
+ cnt++;
+ first = (first+1) % conf->raid_disks;
+ }
+ if (cnt == 0)
+ return 0;
+ } while (first != 0);
+ return 1;
+}
+
static int raid10_spare_active(mddev_t *mddev)
{
int i;
@@ -944,6 +965,8 @@
* very different from resync
*/
return 0;
+ if (!enough(conf))
+ return 0;
for (mirror=0; mirror < mddev->raid_disks; mirror++)
if ( !(p=conf->mirrors+mirror)->rdev) {
@@ -1684,9 +1707,10 @@
init_waitqueue_head(&conf->wait_idle);
init_waitqueue_head(&conf->wait_resume);
- if (!conf->working_disks) {
- printk(KERN_ERR "raid10: no operational mirrors for %s\n",
- mdname(mddev));
+ /* need to check that every block has at least one working mirror */
+ if (!enough(conf)) {
+ printk(KERN_ERR "raid10: not enough operational mirrors for %s\n",
+ mdname(mddev));
goto out_free_conf;
}