filesystems: add set_nlink()

Replace remaining direct i_nlink updates with a new set_nlink()
updater function.

Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Tested-by: Toshiyuki Okajima <toshi.okajima@jp.fujitsu.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
diff --git a/fs/sysfs/inode.c b/fs/sysfs/inode.c
index e23f288..c81b22f 100644
--- a/fs/sysfs/inode.c
+++ b/fs/sysfs/inode.c
@@ -218,7 +218,7 @@
 	}
 
 	if (sysfs_type(sd) == SYSFS_DIR)
-		inode->i_nlink = sd->s_dir.subdirs + 2;
+		set_nlink(inode, sd->s_dir.subdirs + 2);
 }
 
 int sysfs_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat)