From 20076b974a6100fd912a32a12ceca495a53b7075 Mon Sep 17 00:00:00 2001
From: Jens Axboe <axboe@kernel.dk>
Date: Fri, 22 May 2020 10:19:22 -0600
Subject: [PATCH 2087/2944] btrfs: flag files as supporting buffered async
 reads

to #29998112

commit 8730f12b7962b21ea9ad2756abce1e205d22db84 upstream

btrfs uses generic_file_read_iter(), which already supports this.

Acked-by: Chris Mason <clm@fb.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Hao Xu <haoxu@linux.alibaba.com>
Reviewed-by: Joseph Qi <joseph.qi@linux.alibaba.com>
---
 fs/btrfs/file.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index d9d90f0..bfdefd5 100644
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -3328,7 +3328,7 @@ static loff_t btrfs_file_llseek(struct file *file, loff_t offset, int whence)
 
 static int btrfs_file_open(struct inode *inode, struct file *filp)
 {
-	filp->f_mode |= FMODE_NOWAIT;
+	filp->f_mode |= FMODE_NOWAIT | FMODE_BUF_RASYNC;
 	return generic_file_open(inode, filp);
 }
 
-- 
1.8.3.1