Btrfs-progs: add support for device replace procedure

This is the user mode part of the device replace patch series.

The command group "btrfs replace" is added with three commands:
- btrfs replace start srcdev|srcdevid targetdev [-Bfr] mount_point
- btrfs replace status mount_point [-1]
- btrfs replace cancel mount_point

Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de>

1 files changed, 2 insertions, 0 deletions

diff --git a/volumes.h b/volumes.h
index 9ff6182e..9c084061 100644
--- a/volumes.h
+++ b/volumes.h
@@ -182,4 +182,6 @@ int btrfs_add_system_chunk(struct btrfs_trans_handle *trans,
 			   struct btrfs_root *root, struct btrfs_key *key,
 			   struct btrfs_chunk *chunk, int item_size);
 int btrfs_chunk_readonly(struct btrfs_root *root, u64 chunk_offset);
+struct btrfs_device *btrfs_find_device_by_devid(struct btrfs_root *root,
+                                                u64 devid, int instance);
 #endif