1 files changed, 99 insertions, 4 deletions

diff --git a/fs/btrfs/delayed-inode.c b/fs/btrfs/delayed-inode.c
index 222ca8cdc53a..451b00c86f6c 100644
--- a/fs/btrfs/delayed-inode.c
+++ b/fs/btrfs/delayed-inode.c
@@ -1015,6 +1015,18 @@ static void btrfs_release_delayed_inode(struct btrfs_delayed_node *delayed_node)
         }
 }
 
+static void btrfs_release_delayed_iref(struct btrfs_delayed_node *delayed_node)
+{
+        struct btrfs_delayed_root *delayed_root;
+
+        ASSERT(delayed_node->root);
+        clear_bit(BTRFS_DELAYED_NODE_DEL_IREF, &delayed_node->flags);
+        delayed_node->count--;
+
+        delayed_root = delayed_node->root->fs_info->delayed_root;
+        finish_one_item(delayed_root);
+}
+
 static int __btrfs_update_delayed_inode(struct btrfs_trans_handle *trans,
                                         struct btrfs_root *root,
                                         struct btrfs_path *path,
@@ -1023,13 +1035,19 @@ static int __btrfs_update_delayed_inode(struct btrfs_trans_handle *trans,
         struct btrfs_key key;
         struct btrfs_inode_item *inode_item;
         struct extent_buffer *leaf;
+        int mod;
         int ret;
 
         key.objectid = node->inode_id;
         btrfs_set_key_type(&key, BTRFS_INODE_ITEM_KEY);
         key.offset = 0;
 
-        ret = btrfs_lookup_inode(trans, root, path, &key, 1);
+        if (test_bit(BTRFS_DELAYED_NODE_DEL_IREF, &node->flags))
+                mod = -1;
+        else
+                mod = 1;
+
+        ret = btrfs_lookup_inode(trans, root, path, &key, mod);
         if (ret > 0) {
                 btrfs_release_path(path);
                 return -ENOENT;
@@ -1037,19 +1055,58 @@ static int __btrfs_update_delayed_inode(struct btrfs_trans_handle *trans,
                 return ret;
         }
 
-        btrfs_unlock_up_safe(path, 1);
         leaf = path->nodes[0];
         inode_item = btrfs_item_ptr(leaf, path->slots[0],
                                     struct btrfs_inode_item);
         write_extent_buffer(leaf, &node->inode_item, (unsigned long)inode_item,
                             sizeof(struct btrfs_inode_item));
         btrfs_mark_buffer_dirty(leaf);
-        btrfs_release_path(path);
 
+        if (!test_bit(BTRFS_DELAYED_NODE_DEL_IREF, &node->flags))
+                goto no_iref;
+
+        path->slots[0]++;
+        if (path->slots[0] >= btrfs_header_nritems(leaf))
+                goto search;
+again:
+        btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
+        if (key.objectid != node->inode_id)
+                goto out;
+
+        if (key.type != BTRFS_INODE_REF_KEY &&
+            key.type != BTRFS_INODE_EXTREF_KEY)
+                goto out;
+
+        /*
+         * Delayed iref deletion is for the inode who has only one link,
+         * so there is only one iref. The case that several irefs are
+         * in the same item doesn't exist.
+         */
+        btrfs_del_item(trans, root, path);
+out:
+        btrfs_release_delayed_iref(node);
+no_iref:
+        btrfs_release_path(path);
+err_out:
         btrfs_delayed_inode_release_metadata(root, node);
         btrfs_release_delayed_inode(node);
 
-        return 0;
+        return ret;
+
+search:
+        btrfs_release_path(path);
+
+        btrfs_set_key_type(&key, BTRFS_INODE_EXTREF_KEY);
+        key.offset = -1;
+        ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
+        if (ret < 0)
+                goto err_out;
+        ASSERT(ret);
+
+        ret = 0;
+        leaf = path->nodes[0];
+        path->slots[0]--;
+        goto again;
 }
 
 static inline int btrfs_update_delayed_inode(struct btrfs_trans_handle *trans,
@@ -1793,6 +1850,41 @@ release_node:
         return ret;
 }
 
+int btrfs_delayed_delete_inode_ref(struct inode *inode)
+{
+        struct btrfs_delayed_node *delayed_node;
+
+        delayed_node = btrfs_get_or_create_delayed_node(inode);
+        if (IS_ERR(delayed_node))
+                return PTR_ERR(delayed_node);
+
+        /*
+         * We don't reserve space for inode ref deletion is because:
+         * - We ONLY do async inode ref deletion for the inode who has only
+         *   one link(i_nlink == 1), it means there is only one inode ref.
+         *   And in most case, the inode ref and the inode item are in the
+         *   same leaf, and we will deal with them at the same time.
+         *   Since we are sure we will reserve the space for the inode item,
+         *   it is unnecessary to reserve space for inode ref deletion.
+         * - If the inode ref and the inode item are not in the same leaf,
+         *   We also needn't worry about enospc problem, because we reserve
+         *   much more space for the inode update than it needs.
+         * - At the worst, we can steal some space from the global reservation.
+         *   It is very rare.
+         */
+        mutex_lock(&delayed_node->mutex);
+        if (test_bit(BTRFS_DELAYED_NODE_DEL_IREF, &delayed_node->flags))
+                goto release_node;
+
+        set_bit(BTRFS_DELAYED_NODE_DEL_IREF, &delayed_node->flags);
+        delayed_node->count++;
+        atomic_inc(&BTRFS_I(inode)->root->fs_info->delayed_root->items);
+release_node:
+        mutex_unlock(&delayed_node->mutex);
+        btrfs_release_delayed_node(delayed_node);
+        return 0;
+}
+
 static void __btrfs_kill_delayed_node(struct btrfs_delayed_node *delayed_node)
 {
         struct btrfs_root *root = delayed_node->root;
@@ -1815,6 +1907,9 @@ static void __btrfs_kill_delayed_node(struct btrfs_delayed_node *delayed_node)
                 btrfs_release_delayed_item(prev_item);
         }
 
+        if (test_bit(BTRFS_DELAYED_NODE_DEL_IREF, &delayed_node->flags))
+                btrfs_release_delayed_iref(delayed_node);
+
         if (test_bit(BTRFS_DELAYED_NODE_INODE_DIRTY, &delayed_node->flags)) {
                 btrfs_delayed_inode_release_metadata(root, delayed_node);
                 btrfs_release_delayed_inode(delayed_node);