cleancache: zap uuid arg of cleancache_init_shared_fs

Use super_block->s_uuid instead.  Every shared filesystem using cleancache
must now initialize super_block->s_uuid before calling
cleancache_init_shared_fs.  The only one on the tree, ocfs2, already meets
this requirement.

Signed-off-by: Vladimir Davydov <vdavydov@parallels.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: David Vrabel <david.vrabel@citrix.com>
Cc: Mark Fasheh <mfasheh@suse.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Stefan Hengelein <ilendir@googlemail.com>
Cc: Florian Schmaus <fschmaus@gmail.com>
Cc: Andor Daam <andor.daam@googlemail.com>
Cc: Dan Magenheimer <dan.magenheimer@oracle.com>
Cc: Bob Liu <lliubbo@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

fs/ocfs2/super.c

@@ -2336,7 +2336,7 @@ static int ocfs2_initialize_super(struct super_block *sb,
 		mlog_errno(status);
 		goto bail;
 	}
-	cleancache_init_shared_fs((char *)&di->id2.i_super.s_uuid, sb);
+	cleancache_init_shared_fs(sb);
 
 bail:
 	return status;

include/linux/cleancache.h

@@ -36,7 +36,7 @@ struct cleancache_ops {
 extern struct cleancache_ops *
 	cleancache_register_ops(struct cleancache_ops *ops);
 extern void __cleancache_init_fs(struct super_block *);
-extern void __cleancache_init_shared_fs(char *, struct super_block *);
+extern void __cleancache_init_shared_fs(struct super_block *);
 extern int  __cleancache_get_page(struct page *);
 extern void __cleancache_put_page(struct page *);
 extern void __cleancache_invalidate_page(struct address_space *, struct page *);
@@ -78,10 +78,10 @@ static inline void cleancache_init_fs(struct super_block *sb)
 		__cleancache_init_fs(sb);
 }
 
-static inline void cleancache_init_shared_fs(char *uuid, struct super_block *sb)
+static inline void cleancache_init_shared_fs(struct super_block *sb)
 {
 	if (cleancache_enabled)
-		__cleancache_init_shared_fs(uuid, sb);
+		__cleancache_init_shared_fs(sb);
 }
 
 static inline int cleancache_get_page(struct page *page)

mm/cleancache.c

@@ -155,18 +155,18 @@ void __cleancache_init_fs(struct super_block *sb)
 EXPORT_SYMBOL(__cleancache_init_fs);
 
 /* Called by a cleancache-enabled clustered filesystem at time of mount */
-void __cleancache_init_shared_fs(char *uuid, struct super_block *sb)
+void __cleancache_init_shared_fs(struct super_block *sb)
 {
 	int i;
 
 	mutex_lock(&poolid_mutex);
 	for (i = 0; i < MAX_INITIALIZABLE_FS; i++) {
 		if (shared_fs_poolid_map[i] == FS_UNKNOWN) {
 			sb->cleancache_poolid = i + FAKE_SHARED_FS_POOLID_OFFSET;
-			uuids[i] = uuid;
+			uuids[i] = sb->s_uuid;
 			if (cleancache_ops)
 				shared_fs_poolid_map[i] = cleancache_ops->init_shared_fs
-						(uuid, PAGE_SIZE);
+						(sb->s_uuid, PAGE_SIZE);
 			else
 				shared_fs_poolid_map[i] = FS_NO_BACKEND;
 			break;