[PATCH] md: restart a (raid5) reshape that has been aborted due to a read/write error

An error always aborts any resync/recovery/reshape on the understanding that
it will immediately be restarted if that still makes sense.  However a reshape
currently doesn't get restarted.  With this patch it does.

To avoid restarting when it is not possible to do work, we call into the
personality to check that a reshape is ok, and strengthen raid5_check_reshape
to fail if there are too many failed devices.

We also break some code out into a separate function: remove_and_add_spares as
the indent level for that code was getting crazy.

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, 2 insertions, 0 deletions

diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index 11c3d7bfa797..29fc06b47d4e 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -3814,6 +3814,8 @@ static int raid5_check_reshape(mddev_t *mddev)
         if (err)
                 return err;
 
+        if (mddev->degraded > conf->max_degraded)
+                return -EINVAL;
         /* looks like we might be able to manage this */
         return 0;
 }