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authorJeff Layton <jlayton@poochiereds.net>2014-06-10 12:24:40 -0400
committerJeff Layton <jlayton@poochiereds.net>2014-06-10 12:24:40 -0400
commit962bd40bc30e412828e091bfda041b7547e779c8 (patch)
treedc5afa02febd54262708784552b497f11bd0c080
parent64b2d1fbbfda07765dae3f601862796a61b2c451 (diff)
downloadop-kernel-dev-962bd40bc30e412828e091bfda041b7547e779c8.zip
op-kernel-dev-962bd40bc30e412828e091bfda041b7547e779c8.tar.gz
locks: add missing memory barrier in break_deleg
break_deleg is subject to the same potential race as break_lease. Add a memory barrier to prevent it. Signed-off-by: Jeff Layton <jlayton@primarydata.com>
-rw-r--r--include/linux/fs.h6
1 files changed, 6 insertions, 0 deletions
diff --git a/include/linux/fs.h b/include/linux/fs.h
index c3f46e4..22ae796 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1914,6 +1914,12 @@ static inline int break_lease(struct inode *inode, unsigned int mode)
static inline int break_deleg(struct inode *inode, unsigned int mode)
{
+ /*
+ * Since this check is lockless, we must ensure that any refcounts
+ * taken are done before checking inode->i_flock. Otherwise, we could
+ * end up racing with tasks trying to set a new lease on this file.
+ */
+ smp_mb();
if (inode->i_flock)
return __break_lease(inode, mode, FL_DELEG);
return 0;
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