Btrfs: disallow some operations on the device replace target device

This patch adds some code to disallow operations on the device that
is used as the target for the device replace operation.

Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>

1 files changed, 2 insertions, 1 deletions

diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index b4d438f6c2b..98af8379895 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -7468,7 +7468,8 @@ int btrfs_can_relocate(struct btrfs_root *root, u64 bytenr)
                  * check to make sure we can actually find a chunk with enough
                  * space to fit our block group in.
                  */
-                if (device->total_bytes > device->bytes_used + min_free) {
+                if (device->total_bytes > device->bytes_used + min_free &&
+                    !device->is_tgtdev_for_dev_replace) {
                         ret = find_free_dev_extent(device, min_free,
                                                    &dev_offset, NULL);
                         if (!ret)