Btrfs: Remove extent back refs in batches, and avoid duplicate searches
Signed-off-by: Chris Mason <chris.mason@oracle.com>
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 239e9d8..8f44178 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -1251,6 +1251,9 @@
struct btrfs_root *extent_root = info->extent_root;
struct extent_buffer *leaf;
int ret;
+ int extent_slot = 0;
+ int found_extent = 0;
+ int num_to_del = 1;
struct btrfs_extent_item *ei;
u32 refs;
@@ -1267,7 +1270,24 @@
ref_generation,
owner_objectid, owner_offset, 1);
if (ret == 0) {
- ret = btrfs_del_item(trans, extent_root, path);
+ struct btrfs_key found_key;
+ extent_slot = path->slots[0];
+ while(extent_slot > 0) {
+ extent_slot--;
+ btrfs_item_key_to_cpu(path->nodes[0], &found_key,
+ extent_slot);
+ if (found_key.objectid != bytenr)
+ break;
+ if (found_key.type == BTRFS_EXTENT_ITEM_KEY &&
+ found_key.offset == num_bytes) {
+ found_extent = 1;
+ break;
+ }
+ if (path->slots[0] - extent_slot > 5)
+ break;
+ }
+ if (!found_extent)
+ ret = btrfs_del_item(trans, extent_root, path);
} else {
btrfs_print_leaf(extent_root, path->nodes[0]);
WARN_ON(1);
@@ -1276,21 +1296,46 @@
root_objectid, ref_generation, owner_objectid,
owner_offset);
}
- btrfs_release_path(extent_root, path);
- ret = btrfs_search_slot(trans, extent_root, &key, path, -1, 1);
- if (ret < 0)
- return ret;
- BUG_ON(ret);
+ if (!found_extent) {
+ btrfs_release_path(extent_root, path);
+ ret = btrfs_search_slot(trans, extent_root, &key, path, -1, 1);
+ if (ret < 0)
+ return ret;
+ BUG_ON(ret);
+ extent_slot = path->slots[0];
+ }
leaf = path->nodes[0];
- ei = btrfs_item_ptr(leaf, path->slots[0],
+ ei = btrfs_item_ptr(leaf, extent_slot,
struct btrfs_extent_item);
refs = btrfs_extent_refs(leaf, ei);
BUG_ON(refs == 0);
refs -= 1;
btrfs_set_extent_refs(leaf, ei, refs);
+
btrfs_mark_buffer_dirty(leaf);
+ if (refs == 0 && found_extent && path->slots[0] == extent_slot + 1) {
+ /* if the back ref and the extent are next to each other
+ * they get deleted below in one shot
+ */
+ path->slots[0] = extent_slot;
+ num_to_del = 2;
+ } else if (found_extent) {
+ /* otherwise delete the extent back ref */
+ ret = btrfs_del_item(trans, extent_root, path);
+ BUG_ON(ret);
+ /* if refs are 0, we need to setup the path for deletion */
+ if (refs == 0) {
+ btrfs_release_path(extent_root, path);
+ ret = btrfs_search_slot(trans, extent_root, &key, path,
+ -1, 1);
+ if (ret < 0)
+ return ret;
+ BUG_ON(ret);
+ }
+ }
+
if (refs == 0) {
u64 super_used;
u64 root_used;
@@ -1311,8 +1356,8 @@
root_used = btrfs_root_used(&root->root_item);
btrfs_set_root_used(&root->root_item,
root_used - num_bytes);
-
- ret = btrfs_del_item(trans, extent_root, path);
+ ret = btrfs_del_items(trans, extent_root, path, path->slots[0],
+ num_to_del);
if (ret) {
return ret;
}