Introduce the function to get accurate extent length based on extent
tree search.
Signed-off-by: Qu Wenruo <quwenruo@xxxxxxxxxxxxxx>
---
btrfs-map-logical.c | 58 +++++++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 58 insertions(+)
diff --git a/btrfs-map-logical.c b/btrfs-map-logical.c
index e5e2da5..8442779 100644
--- a/btrfs-map-logical.c
+++ b/btrfs-map-logical.c
@@ -35,6 +35,64 @@
* */
static FILE *info_file;
+static int map_one_extent(struct btrfs_fs_info *fs_info,
+ u64 *logical_ret, u64 *len_ret, int search_foward)
+{
+ struct btrfs_path *path;
+ struct btrfs_key key;
+ u64 logical;
+ u64 len = 0;
+ int ret = 0;
+
+ BUG_ON(!logical_ret);
+ logical = *logical_ret;
+
+ path = btrfs_alloc_path();
+ if (!path)
+ return -ENOMEM;
+
+ key.objectid = logical;
+ key.type = 0;
+ key.offset = 0;
+
+ ret = btrfs_search_slot(NULL, fs_info->extent_root, &key, path,
+ 0, 0);
+ if (ret < 0)
+ goto out;
+ BUG_ON(ret == 0);
+ ret = 0;
+
+again:
+ btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
+ if ((search_foward && key.objectid < logical) ||
+ (!search_foward && key.objectid > logical) ||
+ (key.type != BTRFS_EXTENT_ITEM_KEY &&
+ key.type != BTRFS_METADATA_ITEM_KEY)) {
+ if (!search_foward)
+ ret = btrfs_previous_extent_item(fs_info->extent_root,
+ path, 0);
+ else
+ ret = btrfs_next_item(fs_info->extent_root, path);
+ if (ret)
+ goto out;
+ goto again;
+ }
+ logical = key.objectid;
+ if (key.type == BTRFS_METADATA_ITEM_KEY)
+ len = fs_info->tree_root->leafsize;
+ else
+ len = key.offset;
+
+out:
+ btrfs_free_path(path);
+ if (!ret) {
+ *logical_ret = logical;
+ if (len_ret)
+ *len_ret = len;
+ }
+ return ret;
+}
+
static struct extent_buffer * debug_read_block(struct btrfs_root *root,
u64 bytenr, u32 blocksize, u64 copy)
{
--
2.4.3
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