[PATCH] md: make sure the size of a raid5/6 array is a multiple of the chunk size.

Normally the size is chosen as a multiple of the chunk size, but if the size
is explicitly chosen, it might not be.  So we force it.
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>

drivers/md/raid5.c

@@ -1577,6 +1577,9 @@ static int run (mddev_t *mddev)
 	conf->algorithm = mddev->layout;
 	conf->max_nr_stripes = NR_STRIPES;
 
+	/* device size must be a multiple of chunk size */
+	mddev->size &= ~(mddev->chunk_size/1024 -1);
+
 	if (!conf->chunk_size || conf->chunk_size % 4) {
 		printk(KERN_ERR "raid5: invalid chunk size %d for %s\n",
 			conf->chunk_size, mdname(mddev));

drivers/md/raid6main.c

@@ -1741,6 +1741,9 @@ static int run (mddev_t *mddev)
 	conf->algorithm = mddev->layout;
 	conf->max_nr_stripes = NR_STRIPES;
 
+	/* device size must be a multiple of chunk size */
+	mddev->size &= ~(mddev->chunk_size/1024 -1);
+
 	if (conf->raid_disks < 4) {
 		printk(KERN_ERR "raid6: not enough configured devices for %s (%d, minimum 4)\n",
 		       mdname(mddev), conf->raid_disks);