fs/romfs: return f_fsid for statfs(2)

Make romfs return f_fsid info for statfs(2).

Signed-off-by: Coly Li <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
Signed-off-by: Linus Torvalds <[e-mail]>

fs/romfs/super.c

···
  */
 static int romfs_statfs(struct dentry *dentry, struct kstatfs *buf)
 {
+	struct super_block *sb = dentry->d_sb;
+	u64 id = huge_encode_dev(sb->s_bdev->bd_dev);
+
 	buf->f_type = ROMFS_MAGIC;
 	buf->f_namelen = ROMFS_MAXFN;
 	buf->f_bsize = ROMBSIZE;
 	buf->f_bfree = buf->f_bavail = buf->f_ffree;
 	buf->f_blocks =
 		(romfs_maxsize(dentry->d_sb) + ROMBSIZE - 1) >> ROMBSBITS;
+	buf->f_fsid.val[0] = (u32)id;
+	buf->f_fsid.val[1] = (u32)(id >> 32);
 	return 0;
 }