btrfs: free path sooner at __btrfs_unlink_inode()

After calling btrfs_delete_one_dir_name() there's no need for the path
anymore so we can free it immediately after. After that point we do
some btree operations that take time and in those call chains we end up
allocating paths for these operations, so we're unnecessarily holding on
to the path we allocated early at __btrfs_unlink_inode().

So free the path as soon as we don't need it and add a comment. This
also allows to simplify the error path, removing two exit labels and
returning directly when an error happens.

Reviewed-by: Boris Burkov <boris@bur.io>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 15fc3bd272c2d2bda1d467a881e87ef458317002..0f2cbaf8320db463ddb14bc9ff774247fe879489 100644 (file)
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -4215,20 +4215,22 @@ static int __btrfs_unlink_inode(struct btrfs_trans_handle *trans,
        u64 dir_ino = btrfs_ino(dir);
 
        path = btrfs_alloc_path();
-       if (!path) {
-               ret = -ENOMEM;
-               goto out;
-       }
+       if (!path)
+               return -ENOMEM;
 
        di = btrfs_lookup_dir_item(trans, root, path, dir_ino, name, -1);
        if (IS_ERR_OR_NULL(di)) {
-               ret = di ? PTR_ERR(di) : -ENOENT;
-               goto err;
+               btrfs_free_path(path);
+               return di ? PTR_ERR(di) : -ENOENT;
        }
        ret = btrfs_delete_one_dir_name(trans, root, path, di);
+       /*
+        * Down the call chains below we'll also need to allocate a path, so no
+        * need to hold on to this one for longer than necessary.
+        */
+       btrfs_free_path(path);
        if (ret)
-               goto err;
-       btrfs_release_path(path);
+               return ret;
 
        /*
         * If we don't have dir index, we have to get it by looking up
@@ -4254,7 +4256,7 @@ static int __btrfs_unlink_inode(struct btrfs_trans_handle *trans,
           "failed to delete reference to %.*s, root %llu inode %llu parent %llu",
                           name->len, name->name, btrfs_root_id(root), ino, dir_ino);
                btrfs_abort_transaction(trans, ret);
-               goto err;
+               return ret;
        }
 skip_backref:
        if (rename_ctx)
@@ -4263,7 +4265,7 @@ skip_backref:
        ret = btrfs_delete_delayed_dir_index(trans, dir, index);
        if (ret) {
                btrfs_abort_transaction(trans, ret);
-               goto err;
+               return ret;
        }
 
        /*
@@ -4287,19 +4289,14 @@ skip_backref:
         * holding.
         */
        btrfs_run_delayed_iput(fs_info, inode);
-err:
-       btrfs_free_path(path);
-       if (ret)
-               goto out;
 
        btrfs_i_size_write(dir, dir->vfs_inode.i_size - name->len * 2);
        inode_inc_iversion(&inode->vfs_inode);
        inode_set_ctime_current(&inode->vfs_inode);
        inode_inc_iversion(&dir->vfs_inode);
        inode_set_mtime_to_ts(&dir->vfs_inode, inode_set_ctime_current(&dir->vfs_inode));
-       ret = btrfs_update_inode(trans, dir);
-out:
-       return ret;
+
+       return btrfs_update_inode(trans, dir);
 }
 
 int btrfs_unlink_inode(struct btrfs_trans_handle *trans,