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From: NeilBrown <neilb@suse.com>
To: Jeff Layton <jlayton@kernel.org>,
	Alexander Viro <viro@zeniv.linux.org.uk>
Cc: "J. Bruce Fields" <bfields@fieldses.org>,
	Martin Wilck <mwilck@suse.de>,
	linux-fsdevel@vger.kernel.org,
	Frank Filz <ffilzlnx@mindspring.com>,
	linux-kernel@vger.kernel.org
Subject: [PATCH 5/9] fs/locks: always delete_block after waiting.
Date: Wed, 24 Oct 2018 09:43:54 +1100	[thread overview]
Message-ID: <154033463452.29542.11001326804100889939.stgit@noble> (raw)
In-Reply-To: <154033435272.29542.13985568983074440924.stgit@noble>

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@suse.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;
 }



  parent reply	other threads:[~2018-10-23 22:46 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-10-23 22:43 [PATCH 0/9 v3] locks: avoid thundering-herd wake-ups NeilBrown
2018-10-23 22:43 ` [PATCH 8/9] locks: merge posix_unblock_lock() and locks_delete_block() NeilBrown
2018-10-23 22:43 ` [PATCH 6/9] fs/locks: change all *_conflict() functions to return bool NeilBrown
2018-10-23 22:43 ` [PATCH 3/9] NFS: use locks_copy_lock() to copy locks NeilBrown
2018-10-23 22:43 ` [PATCH 2/9] fs/locks: split out __locks_wake_up_blocks() NeilBrown
2018-10-23 22:43 ` [PATCH 9/9] VFS: locks: remove unnecessary white space NeilBrown
2018-10-23 22:43 ` [PATCH 7/9] fs/locks: create a tree of dependent requests NeilBrown
2018-10-23 22:43 ` [PATCH 1/9] fs/locks: rename some lists and pointers NeilBrown
2018-10-23 22:43 ` [PATCH 4/9] fs/locks: allow a lock request to block other requests NeilBrown
2018-10-23 22:43 ` NeilBrown [this message]
2018-10-25 16:04 ` [PATCH 0/9 v3] locks: avoid thundering-herd wake-ups J. Bruce Fields
2018-10-25 19:27   ` Martin Wilck
2018-10-26 13:46 ` Jeff Layton
2018-10-28 22:43   ` NeilBrown
2018-10-29  1:56   ` NeilBrown
2018-10-29 12:38     ` Jeff Layton
2018-10-30 12:04       ` Jeff Layton
2018-10-30 17:56         ` Jeff Layton

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