f2fs: allow parallel DIO reads

This fixes a regression which prevents parallel DIO reads.

Fixes: 0cac5118 ("f2fs: fix to avoid racing in between read and OPU dio write")
Reviewed-by: Daeho Jeong <daehojeong@google.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

fs/f2fs/file.c

@@ -4647,7 +4647,8 @@ static ssize_t f2fs_file_read_iter(struct kiocb *iocb, struct iov_iter *to)
 					iov_iter_count(to), READ);
 
 	/* In LFS mode, if there is inflight dio, wait for its completion */
-	if (f2fs_lfs_mode(F2FS_I_SB(inode)))
+	if (f2fs_lfs_mode(F2FS_I_SB(inode)) &&
+	    get_pages(F2FS_I_SB(inode), F2FS_DIO_WRITE))
 		inode_dio_wait(inode);
 
 	if (f2fs_should_use_dio(inode, iocb, to)) {