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/super.c b/fs/btrfs/super.c
index ef2415896b06..837ad2d27853 100644
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -1354,7 +1354,8 @@ static int btrfs_calc_avail_data_space(struct btrfs_root *root, u64 *free_bytes)
                 min_stripe_size = BTRFS_STRIPE_LEN;
 
         list_for_each_entry(device, &fs_devices->devices, dev_list) {
-                if (!device->in_fs_metadata || !device->bdev)
+                if (!device->in_fs_metadata || !device->bdev ||
+                    device->is_tgtdev_for_dev_replace)
                         continue;
 
                 avail_space = device->total_bytes - device->bytes_used;