Btrfs: Add a helper that finds previous extent item

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

1 files changed, 36 insertions, 44 deletions

diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index b801eb4b3eef..cc89df4493ab 100644
--- 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];