Btrfs: Add a helper that finds previous extent item

Signed-off-by: Chris Mason <chris.mason@oracle.com>

diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index b801eb4..cc89df4 100644 (file)
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -33,6 +33,28 @@ static int finish_current_insert(struct btrfs_trans_handle *trans, struct
                                 btrfs_root *extent_root);
 static int del_pending_extents(struct btrfs_trans_handle *trans, struct
                               btrfs_root *extent_root);
+static int find_previous_extent(struct btrfs_root *root,
+                               struct btrfs_path *path)
+{
+       struct btrfs_key found_key;
+       struct extent_buffer *leaf;
+       int ret;
+
+       while(1) {
+               if (path->slots[0] == 0) {
+                       ret = btrfs_prev_leaf(root, path);
+                       if (ret != 0)
+                               return ret;
+               } else {
+                       path->slots[0]--;
+               }
+               leaf = path->nodes[0];
+               btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
+               if (found_key.type == BTRFS_EXTENT_ITEM_KEY)
+                       return 0;
+       }
+       return 1;
+}
 
 static int cache_block_group(struct btrfs_root *root,
                             struct btrfs_block_group_cache *block_group)
@@ -65,16 +87,19 @@ static int cache_block_group(struct btrfs_root *root,
        first_free = block_group->key.objectid;
        key.objectid = block_group->key.objectid;
        key.offset = 0;
-
        btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
        ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
-
        if (ret < 0)
                return ret;
-
-       if (ret && path->slots[0] > 0)
-               path->slots[0]--;
-
+       ret = find_previous_extent(root, path);
+       if (ret < 0)
+               return ret;
+       if (ret == 0) {
+               leaf = path->nodes[0];
+               btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
+               if (key.objectid + key.offset > first_free)
+                       first_free = key.objectid + key.offset;
+       }
        while(1) {
                leaf = path->nodes[0];
                slot = path->slots[0];
@@ -88,15 +113,10 @@ static int cache_block_group(struct btrfs_root *root,
                                break;
                        }
                }
-
                btrfs_item_key_to_cpu(leaf, &key, slot);
                if (key.objectid < block_group->key.objectid) {
-                       if (btrfs_key_type(&key) != BTRFS_EXTENT_REF_KEY &&
-                           key.objectid + key.offset > first_free)
-                               first_free = key.objectid + key.offset;
                        goto next;
                }
-
                if (key.objectid >= block_group->key.objectid +
                    block_group->key.offset) {
                        break;
@@ -162,11 +182,9 @@ struct btrfs_block_group_cache *btrfs_lookup_block_group(struct
                return block_group;
        return NULL;
 }
-
 static u64 noinline find_search_start(struct btrfs_root *root,
                              struct btrfs_block_group_cache **cache_ret,
-                             u64 search_start, int num,
-                             int data, int full_scan)
+                             u64 search_start, int num, int data)
 {
        int ret;
        struct btrfs_block_group_cache *cache = *cache_ret;
@@ -771,9 +789,7 @@ again:
 out:
        btrfs_free_path(path);
        return total_count;
-
 }
-
 int btrfs_inc_root_ref(struct btrfs_trans_handle *trans,
                       struct btrfs_root *root, u64 owner_objectid)
 {
@@ -1422,7 +1438,7 @@ check_failed:
                                                       orig_search_start);
        }
        search_start = find_search_start(root, &block_group, search_start,
-                                        total_needed, data, full_scan);
+                                        total_needed, data);
        search_start = stripe_align(root, search_start);
        cached_start = search_start;
        btrfs_init_path(path);
@@ -1434,35 +1450,11 @@ check_failed:
        ret = btrfs_search_slot(trans, root, ins, path, 0, 0);
        if (ret < 0)
                goto error;
-
-       if (path->slots[0] > 0) {
-               path->slots[0]--;
-       }
-
+       ret = find_previous_extent(root, path);
+       if (ret < 0)
+               goto error;
        l = path->nodes[0];
        btrfs_item_key_to_cpu(l, &key, path->slots[0]);
-
-       /*
-        * walk backwards to find the first extent item key
-        */
-       while(btrfs_key_type(&key) != BTRFS_EXTENT_ITEM_KEY) {
-               if (path->slots[0] == 0) {
-                       ret = btrfs_prev_leaf(root, path);
-                       if (ret != 0) {
-                               ret = btrfs_search_slot(trans, root, ins,
-                                                       path, 0, 0);
-                               if (ret < 0)
-                                       goto error;
-                               if (path->slots[0] > 0)
-                                       path->slots[0]--;
-                               break;
-                       }
-               } else {
-                       path->slots[0]--;
-               }
-               l = path->nodes[0];
-               btrfs_item_key_to_cpu(l, &key, path->slots[0]);
-       }
        while (1) {
                l = path->nodes[0];
                slot = path->slots[0];