CIFS: Move locks to cifsFileInfo structure

CIFS brlock cache can be used by several file handles if we have a
write-caching lease on the file that is supported by SMB2 protocol.
Prepate the code to handle this situation correctly by sorting brlocks
by a fid to easily push them in portions when lease break comes.

Signed-off-by: Pavel Shilovsky <piastry@etersoft.ru>
diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h
index c41bf6d..03d24a5 100644
--- a/fs/cifs/cifsglob.h
+++ b/fs/cifs/cifsglob.h
@@ -568,7 +568,6 @@
 	__u64 length;
 	__u32 pid;
 	__u8 type;
-	__u16 netfid;
 };
 
 /*
@@ -593,6 +592,10 @@
 struct cifsFileInfo {
 	struct list_head tlist;	/* pointer to next fid owned by tcon */
 	struct list_head flist;	/* next fid (file instance) for this inode */
+	struct list_head llist;	/*
+				 * brlocks held by this fid, protected by
+				 * lock_mutex from cifsInodeInfo structure
+				 */
 	unsigned int uid;	/* allows finding which FileInfo structure */
 	__u32 pid;		/* process id who opened file */
 	__u16 netfid;		/* file id from remote */
@@ -635,9 +638,12 @@
  */
 
 struct cifsInodeInfo {
-	struct list_head llist;		/* brlocks for this inode */
 	bool can_cache_brlcks;
-	struct mutex lock_mutex;	/* protect two fields above */
+	struct mutex lock_mutex;	/*
+					 * protect the field above and llist
+					 * from every cifsFileInfo structure
+					 * from openFileList
+					 */
 	/* BB add in lists for dirty pages i.e. write caching info for oplock */
 	struct list_head openFileList;
 	__u32 cifsAttrs; /* e.g. DOS archive bit, sparse, compressed, system */