Btrfs: make acl functions really no-op if acl is not enabled

So there's no overhead for something we don't use.
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>

fs/btrfs/Makefile

@@ -6,5 +6,7 @@ btrfs-y += super.o ctree.o extent-tree.o print-tree.o root-tree.o dir-item.o \
 	   transaction.o inode.o file.o tree-defrag.o \
 	   extent_map.o sysfs.o struct-funcs.o xattr.o ordered-data.o \
 	   extent_io.o volumes.o async-thread.o ioctl.o locking.o orphan.o \
-	   export.o tree-log.o acl.o free-space-cache.o zlib.o lzo.o \
+	   export.o tree-log.o free-space-cache.o zlib.o lzo.o \
 	   compression.o delayed-ref.o relocation.o delayed-inode.o scrub.o
+
+btrfs-$(CONFIG_BTRFS_FS_POSIX_ACL) += acl.o

fs/btrfs/acl.c

@@ -28,8 +28,6 @@
 #include "btrfs_inode.h"
 #include "xattr.h"
 
-#ifdef CONFIG_BTRFS_FS_POSIX_ACL
-
 static struct posix_acl *btrfs_get_acl(struct inode *inode, int type)
 {
 	int size;
@@ -318,18 +316,3 @@ const struct xattr_handler btrfs_xattr_acl_access_handler = {
 	.get	= btrfs_xattr_acl_get,
 	.set	= btrfs_xattr_acl_set,
 };
-
-#else /* CONFIG_BTRFS_FS_POSIX_ACL */
-
-int btrfs_acl_chmod(struct inode *inode)
-{
-	return 0;
-}
-
-int btrfs_init_acl(struct btrfs_trans_handle *trans,
-		   struct inode *inode, struct inode *dir)
-{
-	return 0;
-}
-
-#endif /* CONFIG_BTRFS_FS_POSIX_ACL */

fs/btrfs/ctree.h

@@ -2650,12 +2650,21 @@ do {								\
 /* acl.c */
 #ifdef CONFIG_BTRFS_FS_POSIX_ACL
 int btrfs_check_acl(struct inode *inode, int mask, unsigned int flags);
-#else
-#define btrfs_check_acl NULL
-#endif
 int btrfs_init_acl(struct btrfs_trans_handle *trans,
 		   struct inode *inode, struct inode *dir);
 int btrfs_acl_chmod(struct inode *inode);
+#else
+#define btrfs_check_acl NULL
+static inline int btrfs_init_acl(struct btrfs_trans_handle *trans,
+				 struct inode *inode, struct inode *dir)
+{
+	return 0;
+}
+static inline int btrfs_acl_chmod(struct inode *inode)
+{
+	return 0;
+}
+#endif
 
 /* relocation.c */
 int btrfs_relocate_block_group(struct btrfs_root *root, u64 group_start);