btrfs: use btrfs inodes in btrfs_rmdir() to avoid so much usage of BTRFS_I()

Almost everywhere we want to use a btrfs inode and therefore we have a
lot of calls to BTRFS_I(), making the code more verbose. Instead use btrfs
inode local variables to avoid so much use of BTRFS_I().

Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>

Author: fdmanana

fs/btrfs/inode.c

@@ -4701,32 +4701,33 @@ int btrfs_delete_subvolume(struct btrfs_inode *dir, struct dentry *dentry)
 	return ret;
 }
 
-static int btrfs_rmdir(struct inode *dir, struct dentry *dentry)
+static int btrfs_rmdir(struct inode *vfs_dir, struct dentry *dentry)
 {
-	struct inode *inode = d_inode(dentry);
-	struct btrfs_fs_info *fs_info = BTRFS_I(inode)->root->fs_info;
+	struct btrfs_inode *dir = BTRFS_I(vfs_dir);
+	struct btrfs_inode *inode = BTRFS_I(d_inode(dentry));
+	struct btrfs_fs_info *fs_info = inode->root->fs_info;
 	int ret = 0;
 	struct btrfs_trans_handle *trans;
 	struct fscrypt_name fname;
 
-	if (inode->i_size > BTRFS_EMPTY_DIR_SIZE)
+	if (inode->vfs_inode.i_size > BTRFS_EMPTY_DIR_SIZE)
 		return -ENOTEMPTY;
-	if (btrfs_ino(BTRFS_I(inode)) == BTRFS_FIRST_FREE_OBJECTID) {
+	if (btrfs_ino(inode) == BTRFS_FIRST_FREE_OBJECTID) {
 		if (unlikely(btrfs_fs_incompat(fs_info, EXTENT_TREE_V2))) {
 			btrfs_err(fs_info,
 			"extent tree v2 doesn't support snapshot deletion yet");
 			return -EOPNOTSUPP;
 		}
-		return btrfs_delete_subvolume(BTRFS_I(dir), dentry);
+		return btrfs_delete_subvolume(dir, dentry);
 	}
 
-	ret = fscrypt_setup_filename(dir, &dentry->d_name, 1, &fname);
+	ret = fscrypt_setup_filename(vfs_dir, &dentry->d_name, 1, &fname);
 	if (ret)
 		return ret;
 
 	/* This needs to handle no-key deletions later on */
 
-	trans = __unlink_start_trans(BTRFS_I(dir));
+	trans = __unlink_start_trans(dir);
 	if (IS_ERR(trans)) {
 		ret = PTR_ERR(trans);
 		goto out_notrans;
@@ -4746,22 +4747,22 @@ static int btrfs_rmdir(struct inode *dir, struct dentry *dentry)
 	 * This is because we can't unlink other roots when replaying the dir
 	 * deletes for directory foo.
 	 */
-	if (BTRFS_I(inode)->last_unlink_trans >= trans->transid)
-		btrfs_record_snapshot_destroy(trans, BTRFS_I(dir));
+	if (inode->last_unlink_trans >= trans->transid)
+		btrfs_record_snapshot_destroy(trans, dir);
 
-	if (unlikely(btrfs_ino(BTRFS_I(inode)) == BTRFS_EMPTY_SUBVOL_DIR_OBJECTID)) {
-		ret = btrfs_unlink_subvol(trans, BTRFS_I(dir), dentry);
+	if (unlikely(btrfs_ino(inode) == BTRFS_EMPTY_SUBVOL_DIR_OBJECTID)) {
+		ret = btrfs_unlink_subvol(trans, dir, dentry);
 		goto out;
 	}
 
-	ret = btrfs_orphan_add(trans, BTRFS_I(inode));
+	ret = btrfs_orphan_add(trans, inode);
 	if (ret)
 		goto out;
 
 	/* now the directory is empty */
-	ret = btrfs_unlink_inode(trans, BTRFS_I(dir), BTRFS_I(inode), &fname.disk_name);
+	ret = btrfs_unlink_inode(trans, dir, inode, &fname.disk_name);
 	if (!ret)
-		btrfs_i_size_write(BTRFS_I(inode), 0);
+		btrfs_i_size_write(inode, 0);
 out:
 	btrfs_end_transaction(trans);
 out_notrans: