[PATCH] md: Fix rdev_size_store with size = 0

[Chris Webb <chris@arachsys.com>]

Hi Neil. You accepted a patch from me back at the end of June which allowed
/sys/block/mdX/md/rdY/size to change on running arrays. It supported a value
of zero to fill all the space on the underlying device. However, a later
patch tidying up rdev_size_store broke the size = 0 functionality by testing
for size < my_mddev->size slightly too early. The following patch fixes
this.

Best wishes,

Chris.


From: Chris Webb <chris@arachsys.com>

Fix rdev_size_store with size = 0

Signed-off-by: Chris Webb <chris@arachsys.com>

diff --git a/drivers/md/md.c b/drivers/md/md.c
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -2109,8 +2109,6 @@
 
 	if (strict_strtoull(buf, 10, &size) < 0)
 		return -EINVAL;
-	if (size < my_mddev->size)
-		return -EINVAL;
 	if (my_mddev->pers && rdev->raid_disk >= 0) {
 		if (my_mddev->persistent) {
 			size = super_types[my_mddev->major_version].
@@ -2121,9 +2119,9 @@
 			size = (rdev->bdev->bd_inode->i_size >> 10);
 			size -= rdev->data_offset/2;
 		}
-		if (size < my_mddev->size)
-			return -EINVAL; /* component must fit device */
-	}
+	}
+	if (size < my_mddev->size)
+		return -EINVAL; /* component must fit device */
 
 	rdev->size = size;
 	if (size > oldsize && my_mddev->external) {