f2fs: fix to clear FI_NO_PREALLOC

We need to clear FI_NO_PREALLOC flag in error path of f2fs_file_write_iter,
otherwise we will lose the chance to preallocate blocks in latter write()
at one time.

Fixes: dc91de78e5e1 ("f2fs: do not preallocate blocks which has wrong buffer")
Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

fs/f2fs/file.c

@@ -2525,6 +2525,7 @@ static ssize_t f2fs_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
 
 		err = f2fs_preallocate_blocks(iocb, from);
 		if (err) {
+			clear_inode_flag(inode, FI_NO_PREALLOC);
 			inode_unlock(inode);
 			return err;
 		}