hfsplus: report create_date to kstat.btime

The create_date field of inode in hfsplus is corresponding to
kstat.btime and could be reported in statx.

Link: https://lkml.kernel.org/r/20210416172147.8736-1-cccheng@synology.com
Signed-off-by: Chung-Chiang Cheng <cccheng@synology.com>
Reviewed-by: Viacheslav Dubeyko <slava@dubeyko.com>
Cc: Christian Brauner <christian.brauner@ubuntu.com>
Cc: James Morris <jamorris@linux.microsoft.com>
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

fs/hfsplus/inode.c

@@ -281,6 +281,11 @@ int hfsplus_getattr(struct user_namespace *mnt_userns, const struct path *path,
 	struct inode *inode = d_inode(path->dentry);
 	struct hfsplus_inode_info *hip = HFSPLUS_I(inode);
 
+	if (request_mask & STATX_BTIME) {
+		stat->result_mask |= STATX_BTIME;
+		stat->btime = hfsp_mt2ut(hip->create_date);
+	}
+
 	if (inode->i_flags & S_APPEND)
 		stat->attributes |= STATX_ATTR_APPEND;
 	if (inode->i_flags & S_IMMUTABLE)