From: Steven Whitehouse <swhiteho@redhat.com>
Date: Wed, 9 Mar 2011 11:14:32 +0000 (+0000)
Subject: GFS2: Remove potential race in flock code
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=0a33443b38746f35fc4acc8a5af6c7099e03ea40;p=linux-beck.git

GFS2: Remove potential race in flock code

This patch ensures that we always wait for glock demotion when
dropping flocks on a file in order to prevent any race
conditions associated with further flock calls or closing
the file.

Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
---

diff --git a/fs/gfs2/file.c b/fs/gfs2/file.c
index 216ad2774a62..2878481f72a9 100644
--- a/fs/gfs2/file.c
+++ b/fs/gfs2/file.c
@@ -981,8 +981,10 @@ static void do_unflock(struct file *file, struct file_lock *fl)
 
 	mutex_lock(&fp->f_fl_mutex);
 	flock_lock_file_wait(file, fl);
-	if (fl_gh->gh_gl)
-		gfs2_glock_dq_uninit(fl_gh);
+	if (fl_gh->gh_gl) {
+		gfs2_glock_dq_wait(fl_gh);
+		gfs2_holder_uninit(fl_gh);
+	}
 	mutex_unlock(&fp->f_fl_mutex);
 }