Patch "[PATCH] wrappers for ->i_mutex access" has been added to the 4.4-stable tree

Patch "[PATCH] wrappers for ->i_mutex access" has been added to the 4.4-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    [PATCH] wrappers for ->i_mutex access

to the 4.4-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     wrappers-for-i_mutex-access.patch
and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From 5955102c9984fa081b2d570cfac75c97eecf8f3b Mon Sep 17 00:00:00 2001
From: Al Viro <viro@zeniv.linux.org.uk>
Date: Fri, 22 Jan 2016 15:40:57 -0500
Subject: [PATCH] wrappers for ->i_mutex access

From: Al Viro <viro@zeniv.linux.org.uk>

commit 5955102c9984fa081b2d570cfac75c97eecf8f3b upstream

parallel to mutex_{lock,unlock,trylock,is_locked,lock_nested},
inode_foo(inode) being mutex_foo(&inode->i_mutex).

Please, use those for access to ->i_mutex; over the coming cycle
->i_mutex will become rwsem, with ->lookup() done with it held
only shared.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
[only the fs.h change included to make backports easier - gregkh]
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 include/linux/fs.h |   29 +++++++++++++++++++++++++++--
 1 file changed, 27 insertions(+), 2 deletions(-)

--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -710,6 +710,31 @@ enum inode_i_mutex_lock_class
 	I_MUTEX_PARENT2,
 };
 
+static inline void inode_lock(struct inode *inode)
+{
+	mutex_lock(&inode->i_mutex);
+}
+
+static inline void inode_unlock(struct inode *inode)
+{
+	mutex_unlock(&inode->i_mutex);
+}
+
+static inline int inode_trylock(struct inode *inode)
+{
+	return mutex_trylock(&inode->i_mutex);
+}
+
+static inline int inode_is_locked(struct inode *inode)
+{
+	return mutex_is_locked(&inode->i_mutex);
+}
+
+static inline void inode_lock_nested(struct inode *inode, unsigned subclass)
+{
+	mutex_lock_nested(&inode->i_mutex, subclass);
+}
+
 void lock_two_nondirectories(struct inode *, struct inode*);
 void unlock_two_nondirectories(struct inode *, struct inode*);
 
@@ -3029,8 +3054,8 @@ static inline bool dir_emit_dots(struct
 }
 static inline bool dir_relax(struct inode *inode)
 {
-	mutex_unlock(&inode->i_mutex);
-	mutex_lock(&inode->i_mutex);
+	inode_unlock(inode);
+	inode_lock(inode);
 	return !IS_DEADDIR(inode);
 }
 


Patches currently in stable-queue which might be from viro@zeniv.linux.org.uk are

queue-4.4/wrappers-for-i_mutex-access.patch
queue-4.4/0113-ecryptfs-fix-handling-of-directory-opening.patch