hfsplus: return file attributes on statx

The immutable, append-only and no-dump attributes can only be retrieved
with an ioctl; implement the ->getattr() method to return them on statx.
Do not return the inode birthtime yet, because the issue of how best to
handle the post-2038 timestamps is still under discussion.

This patch is needed to pass xfstests generic/424.

Link: http://lkml.kernel.org/r/20181014163558.sxorxlzjqccq2lpw@eaf
Signed-off-by: Ernesto A. Fernández <[e-mail]>
Cc: Viacheslav Dubeyko <[e-mail]>
Cc: Al Viro <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
Signed-off-by: Linus Torvalds <[e-mail]>

fs/hfsplus/dir.c

···
 	.symlink		= hfsplus_symlink,
 	.mknod			= hfsplus_mknod,
 	.rename			= hfsplus_rename,
+	.getattr		= hfsplus_getattr,
 	.listxattr		= hfsplus_listxattr,
 };
 

fs/hfsplus/hfsplus_fs.h

···
 			      struct hfsplus_fork_raw *fork);
 int hfsplus_cat_read_inode(struct inode *inode, struct hfs_find_data *fd);
 int hfsplus_cat_write_inode(struct inode *inode);
+int hfsplus_getattr(const struct path *path, struct kstat *stat,
+		    u32 request_mask, unsigned int query_flags);
 int hfsplus_file_fsync(struct file *file, loff_t start, loff_t end,
 		       int datasync);
 

fs/hfsplus/inode.c

···
 	return 0;
 }
 
+int hfsplus_getattr(const struct path *path, struct kstat *stat,
+		    u32 request_mask, unsigned int query_flags)
+{
+	struct inode *inode = d_inode(path->dentry);
+	struct hfsplus_inode_info *hip = HFSPLUS_I(inode);
+
+	if (inode->i_flags & S_APPEND)
+		stat->attributes |= STATX_ATTR_APPEND;
+	if (inode->i_flags & S_IMMUTABLE)
+		stat->attributes |= STATX_ATTR_IMMUTABLE;
+	if (hip->userflags & HFSPLUS_FLG_NODUMP)
+		stat->attributes |= STATX_ATTR_NODUMP;
+
+	stat->attributes_mask |= STATX_ATTR_APPEND | STATX_ATTR_IMMUTABLE |
+				 STATX_ATTR_NODUMP;
+
+	generic_fillattr(inode, stat);
+	return 0;
+}
+
 int hfsplus_file_fsync(struct file *file, loff_t start, loff_t end,
 		       int datasync)
 {
···
 
 static const struct inode_operations hfsplus_file_inode_operations = {
 	.setattr	= hfsplus_setattr,
+	.getattr	= hfsplus_getattr,
 	.listxattr	= hfsplus_listxattr,
 };