fuse: add fusectl interface to max_background

Make the max_background and congestion_threshold parameters of a FUSE
mount tunable at runtime by adding the respective knobs to its directory
within the fusectl filesystem.

Signed-off-by: Csaba Henk <csaba@gluster.com>
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
diff --git a/fs/fuse/fuse_i.h b/fs/fuse/fuse_i.h
index 6bcfab0..fc9c79f 100644
--- a/fs/fuse/fuse_i.h
+++ b/fs/fuse/fuse_i.h
@@ -32,7 +32,7 @@
 #define FUSE_NAME_MAX 1024
 
 /** Number of dentries for each connection in the control filesystem */
-#define FUSE_CTL_NUM_DENTRIES 3
+#define FUSE_CTL_NUM_DENTRIES 5
 
 /** If the FUSE_DEFAULT_PERMISSIONS flag is given, the filesystem
     module will check permissions based on the file mode.  Otherwise no
@@ -49,6 +49,10 @@
 /** Global mutex protecting fuse_conn_list and the control filesystem */
 extern struct mutex fuse_mutex;
 
+/** Module parameters */
+extern unsigned max_user_bgreq;
+extern unsigned max_user_congthresh;
+
 /** FUSE inode */
 struct fuse_inode {
 	/** Inode data */