From:   Vasily Averin <vvs@virtuozzo.com>
Subject: [PATCH] ksmbd: use F_SETLK to force vfs_file_lock() to return
 asynchronously
To:     Namjae Jeon <linkinjeon@kernel.org>,
        Sergey Senozhatsky <senozhatsky@chromium.org>,
        Steve French <sfrench@samba.org>,
        Hyunchul Lee <hyc.lee@gmail.com>
Cc:     kernel@openvz.org, linux-cifs@vger.kernel.org,
        linux-kernel@vger.kernel.org
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Date:   Sun, 19 Dec 2021 12:34:54 +0300
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To avoid possible deadlock ksmbd should process locks asynchronously.
Callers expecting vfs_file_locks() to return asynchronously should only
use F_SETLK, not F_SETLKW.

Signed-off-by: Vasily Averin <vvs@virtuozzo.com>
---
 fs/ksmbd/smb2pdu.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/fs/ksmbd/smb2pdu.c b/fs/ksmbd/smb2pdu.c
index 0c020deb76bb..34f333549767 100644
--- a/fs/ksmbd/smb2pdu.c
+++ b/fs/ksmbd/smb2pdu.c
@@ -6646,13 +6646,13 @@ static int smb2_set_flock_flags(struct file_lock *flock, int flags)
 	switch (flags) {
 	case SMB2_LOCKFLAG_SHARED:
 		ksmbd_debug(SMB, "received shared request\n");
-		cmd = F_SETLKW;
+		cmd = F_SETLK;
 		flock->fl_type = F_RDLCK;
 		flock->fl_flags |= FL_SLEEP;
 		break;
 	case SMB2_LOCKFLAG_EXCLUSIVE:
 		ksmbd_debug(SMB, "received exclusive request\n");
-		cmd = F_SETLKW;
+		cmd = F_SETLK;
 		flock->fl_type = F_WRLCK;
 		flock->fl_flags |= FL_SLEEP;
 		break;
-- 
2.25.1