linux-kernel - [PATCH 5/9] fs/locks: always delete

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Date:   Wed, 24 Oct 2018 09:43:54 +1100
From:   NeilBrown <neilb@...e.com>
To:     Jeff Layton <jlayton@...nel.org>,
        Alexander Viro <viro@...iv.linux.org.uk>
Cc:     "J. Bruce Fields" <bfields@...ldses.org>,
        Martin Wilck <mwilck@...e.de>, linux-fsdevel@...r.kernel.org,
        Frank Filz <ffilzlnx@...dspring.com>,
        linux-kernel@...r.kernel.org
Subject: [PATCH 5/9] fs/locks: always delete_block after waiting.

Now that requests can block other requests, we
need to be careful to always clean up those blocked
requests.
Any time that we wait for a request, we might have
other requests attached, and when we stop waiting,
we must clean them up.
If the lock was granted, the requests might have been
moved to the new lock, though when merged with a
pre-exiting lock, this might not happen.
In all cases we don't want blocked locks to remain
attached, so we remove them to be safe.

Signed-off-by: NeilBrown <neilb@...e.com>
---
 fs/locks.c |   24 +++++++++---------------
 1 file changed, 9 insertions(+), 15 deletions(-)

diff --git a/fs/locks.c b/fs/locks.c
index d362e84a7176..e2ad0a7986c5 100644
--- a/fs/locks.c
+++ b/fs/locks.c
@@ -1268,12 +1268,10 @@ static int posix_lock_inode_wait(struct inode *inode, struct file_lock *fl)
 		if (error != FILE_LOCK_DEFERRED)
 			break;
 		error = wait_event_interruptible(fl->fl_wait, !fl->fl_blocker);
-		if (!error)
-			continue;
-
-		locks_delete_block(fl);
-		break;
+		if (error)
+			break;
 	}
+	locks_delete_block(fl);
 	return error;
 }
 
@@ -1962,12 +1960,10 @@ static int flock_lock_inode_wait(struct inode *inode, struct file_lock *fl)
 		if (error != FILE_LOCK_DEFERRED)
 			break;
 		error = wait_event_interruptible(fl->fl_wait, !fl->fl_blocker);
-		if (!error)
-			continue;
-
-		locks_delete_block(fl);
-		break;
+		if (error)
+			break;
 	}
+	locks_delete_block(fl);
 	return error;
 }
 
@@ -2241,12 +2237,10 @@ static int do_lock_file_wait(struct file *filp, unsigned int cmd,
 		if (error != FILE_LOCK_DEFERRED)
 			break;
 		error = wait_event_interruptible(fl->fl_wait, !fl->fl_blocker);
-		if (!error)
-			continue;
-
-		locks_delete_block(fl);
-		break;
+		if (error)
+			break;
 	}
+	locks_delete_block(fl);
 
 	return error;
 }