linux-kernel - [PATCH v2 2/6] locks: don't check for race with close when setting OFD lock

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Message-Id: <1452261014-1682-3-git-send-email-jeff.layton@primarydata.com>
Date:	Fri,  8 Jan 2016 08:50:10 -0500
From:	Jeff Layton <jlayton@...chiereds.net>
To:	linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org
Cc:	Dmitry Vyukov <dvyukov@...gle.com>,
	"J. Bruce Fields" <bfields@...ldses.org>,
	Alexander Viro <viro@...iv.linux.org.uk>,
	syzkaller <syzkaller@...glegroups.com>,
	Kostya Serebryany <kcc@...gle.com>,
	Alexander Potapenko <glider@...gle.com>,
	Sasha Levin <sasha.levin@...cle.com>,
	Eric Dumazet <edumazet@...gle.com>
Subject: [PATCH v2 2/6] locks: don't check for race with close when setting OFD lock

We don't clean out OFD locks on close(), so there's no need to check
for a race with them here. They'll get cleaned out at the same time
that flock locks are.

Signed-off-by: Jeff Layton <jeff.layton@...marydata.com>
---
 fs/locks.c | 16 ++++++++++------
 1 file changed, 10 insertions(+), 6 deletions(-)

diff --git a/fs/locks.c b/fs/locks.c
index c263aff793bc..e72077d5a664 100644
--- a/fs/locks.c
+++ b/fs/locks.c
@@ -2219,10 +2219,12 @@ int fcntl_setlk(unsigned int fd, struct file *filp, unsigned int cmd,
 	error = do_lock_file_wait(filp, cmd, file_lock);
 
 	/*
-	 * Attempt to detect a close/fcntl race and recover by
-	 * releasing the lock that was just acquired.
+	 * Attempt to detect a close/fcntl race and recover by releasing the
+	 * lock that was just acquired. There is no need to do that when we're
+	 * unlocking though, or for OFD locks.
 	 */
-	if (!error && file_lock->fl_type != F_UNLCK) {
+	if (!error && file_lock->fl_type != F_UNLCK &&
+	    !(file_lock->fl_flags & FL_OFDLCK)) {
 		/*
 		 * We need that spin_lock here - it prevents reordering between
 		 * update of i_flctx->flc_posix and check for it done in
@@ -2361,10 +2363,12 @@ int fcntl_setlk64(unsigned int fd, struct file *filp, unsigned int cmd,
 	error = do_lock_file_wait(filp, cmd, file_lock);
 
 	/*
-	 * Attempt to detect a close/fcntl race and recover by
-	 * releasing the lock that was just acquired.
+	 * Attempt to detect a close/fcntl race and recover by releasing the
+	 * lock that was just acquired. There is no need to do that when we're
+	 * unlocking though, or for OFD locks.
 	 */
-	if (!error && file_lock->fl_type != F_UNLCK) {
+	if (!error && file_lock->fl_type != F_UNLCK &&
+	    !(file_lock->fl_flags & FL_OFDLCK)) {
 		/*
 		 * We need that spin_lock here - it prevents reordering between
 		 * update of i_flctx->flc_posix and check for it done in
-- 
2.5.0