f2fs: clear nlink if fail to add_link

We don't need to keep incomplete created inode in cache, so if we fail to
add link into directory during new inode creation, it's better to set
nlink of inode to zero, then we can evict inode immediately. Otherwise
release of nid belong to inode will be delayed until inode cache is being
shrunk, it may cause a seemingly endless loop while allocating free nids
in time of testing generic/269 case of fstest suit.
Signed-off-by: Chao Yu <yuchao0@huawei.com>
[Jaegeuk Kim: add update_inode_page to fix kernel panic]
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

fs/f2fs/inode.c

@@ -387,6 +387,8 @@ void f2fs_evict_inode(struct inode *inode)
 		f2fs_lock_op(sbi);
 		err = remove_inode_page(inode);
 		f2fs_unlock_op(sbi);
+		if (err == -ENOENT)
+			err = 0;
 	}
 
 	/* give more chances, if ENOMEM case */
@@ -427,6 +429,18 @@ void handle_failed_inode(struct inode *inode)
 	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
 	struct node_info ni;
 
+	/*
+	 * clear nlink of inode in order to release resource of inode
+	 * immediately.
+	 */
+	clear_nlink(inode);
+
+	/*
+	 * we must call this to avoid inode being remained as dirty, resulting
+	 * in a panic when flushing dirty inodes in gdirty_list.
+	 */
+	update_inode_page(inode);
+
 	/* don't make bad inode, since it becomes a regular file. */
 	unlock_new_inode(inode);