[PATCH 3/5] btrfs-progs: image: Remove all existing dev extents for later rebuild

[Qu Wenruo <wqu@xxxxxxxx>]

This patch will remove all existing dev extents for later rebuild.

Signed-off-by: Qu Wenruo <wqu@xxxxxxxx>
---
 image/main.c | 68 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 68 insertions(+)

diff --git a/image/main.c b/image/main.c
index 9060f6b1b665..707568f22e01 100644
--- a/image/main.c
+++ b/image/main.c
@@ -2210,6 +2210,70 @@ static void fixup_block_groups(struct btrfs_trans_handle *trans,
 	}
 }
 
+static int remove_all_dev_extents(struct btrfs_trans_handle *trans,
+				  struct btrfs_fs_info *fs_info)
+{
+	struct btrfs_root *root = fs_info->dev_root;
+	struct btrfs_path path;
+	struct btrfs_key key;
+	struct extent_buffer *leaf;
+	int slot;
+	int ret;
+
+	key.objectid = 1;
+	key.type = BTRFS_DEV_EXTENT_KEY;
+	key.offset = 0;
+	btrfs_init_path(&path);
+
+	ret = btrfs_search_slot(trans, root, &key, &path, -1, 1);
+	if (ret < 0) {
+		error("failed to search dev tree: %s", strerror(-ret));
+		return ret;
+	}
+
+	while (1) {
+		slot = path.slots[0];
+		leaf = path.nodes[0];
+		if (slot >= btrfs_header_nritems(leaf)) {
+			ret = btrfs_next_leaf(root, &path);
+			if (ret < 0) {
+				error("failed to search dev tree: %s",
+					strerror(-ret));
+				goto out;
+			}
+			if (ret > 0) {
+				ret = 0;
+				goto out;
+			}
+		}
+
+		btrfs_item_key_to_cpu(leaf, &key, slot);
+		if (key.type != BTRFS_DEV_EXTENT_KEY)
+			break;
+		ret = btrfs_del_item(trans, root, &path);
+		if (ret < 0) {
+			error("failed to delete dev extent %llu, %llu: %s",
+				key.objectid, key.offset, strerror(-ret));
+			goto out;
+		}
+	}
+out:
+	btrfs_release_path(&path);
+	return ret;
+}
+
+static int fixup_dev_extents(struct btrfs_trans_handle *trans,
+			     struct btrfs_fs_info *fs_info)
+{
+	int ret;
+
+	ret = remove_all_dev_extents(trans, fs_info);
+	if (ret < 0)
+		error("failed to remove all existing dev extents: %s",
+			strerror(-ret));
+	return ret;
+}
+
 static int fixup_chunks_and_devices(struct btrfs_fs_info *fs_info,
 			 struct mdrestore_struct *mdres, off_t dev_size)
 {
@@ -2227,6 +2291,10 @@ static int fixup_chunks_and_devices(struct btrfs_fs_info *fs_info,
 	}
 
 	fixup_block_groups(trans, fs_info);
+	ret = fixup_dev_extents(trans, fs_info);
+	if (ret < 0)
+		goto error;
+
 	ret = fixup_device_size(trans, fs_info, mdres, dev_size);
 	if (ret < 0)
 		goto error;
-- 
2.19.2