[SYSFS] Add a declaration for fs_subsys

[Steven Whitehouse <swhiteho@redhat.com>]

The fs_subsys of sysfs does not have a declaration in any header
file, despite it being an exported symbol. This patch adds one so
that modules don't have to add their own. This is something used
by GFS2 (and already in the GFS2 tree) but I think can safely be
considered generic infrastructure.

Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
---
 include/linux/fs.h |    3 +++
 1 files changed, 3 insertions(+), 0 deletions(-)

diff --git a/include/linux/fs.h b/include/linux/fs.h
index 1d3e601..48f9821 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1377,6 +1377,9 @@ extern struct subsystem fs_subsys;
 #define FLOCK_VERIFY_READ  1
 #define FLOCK_VERIFY_WRITE 2
 
+/* /sys/fs */
+extern struct subsystem fs_subsys;
+
 extern int locks_mandatory_locked(struct inode *);
 extern int locks_mandatory_area(int, struct inode *, struct file *, loff_t, size_t);
 
-- 
1.4.1