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/9p/vfs_inode_dotl.c b/fs/9p/vfs_inode_dotl.c
index aded79f..0b5745e 100644
--- a/fs/9p/vfs_inode_dotl.c
+++ b/fs/9p/vfs_inode_dotl.c
@@ -606,7 +606,7 @@
 		inode->i_ctime.tv_nsec = stat->st_ctime_nsec;
 		inode->i_uid = stat->st_uid;
 		inode->i_gid = stat->st_gid;
-		inode->i_nlink = stat->st_nlink;
+		set_nlink(inode, stat->st_nlink);
 
 		mode = stat->st_mode & S_IALLUGO;
 		mode |= inode->i_mode & ~S_IALLUGO;
@@ -632,7 +632,7 @@
 		if (stat->st_result_mask & P9_STATS_GID)
 			inode->i_gid = stat->st_gid;
 		if (stat->st_result_mask & P9_STATS_NLINK)
-			inode->i_nlink = stat->st_nlink;
+			set_nlink(inode, stat->st_nlink);
 		if (stat->st_result_mask & P9_STATS_MODE) {
 			inode->i_mode = stat->st_mode;
 			if ((S_ISBLK(inode->i_mode)) ||