static bool smb2_set_sparse(const unsigned int xid, struct cifs_tcon *tcon,
		struct cifsFileInfo *cfile, struct inode *inode, __u8 setsparse)
{
	struct cifsInodeInfo *cifsi;
	int rc;

	cifsi = CIFS_I(inode);

	/* if file already sparse don't bother setting sparse again */
	if ((cifsi->cifsAttrs & FILE_ATTRIBUTE_SPARSE_FILE) && setsparse)
		return true; /* already sparse */

	if (!(cifsi->cifsAttrs & FILE_ATTRIBUTE_SPARSE_FILE) && !setsparse)
		return true; /* already not sparse */

	/*
	 * Can't check for sparse support on share the usual way via the
	 * FS attribute info (FILE_SUPPORTS_SPARSE_FILES) on the share
	 * since Samba server doesn't set the flag on the share, yet
	 * supports the set sparse FSCTL and returns sparse correctly
	 * in the file attributes. If we fail setting sparse though we
	 * mark that server does not support sparse files for this share
	 * to avoid repeatedly sending the unsupported fsctl to server
	 * if the file is repeatedly extended.
	 */
	if (tcon->broken_sparse_sup)
		return false;

	rc = SMB2_ioctl(xid, tcon, cfile->fid.persistent_fid,
			cfile->fid.volatile_fid, FSCTL_SET_SPARSE,
			true /* is_fctl */,
			&setsparse, 1, CIFSMaxBufSize, NULL, NULL);
	if (rc) {
		tcon->broken_sparse_sup = true;
		cifs_dbg(FYI, "set sparse rc = %d\n", rc);
		return false;
	}

	if (setsparse)
		cifsi->cifsAttrs |= FILE_ATTRIBUTE_SPARSE_FILE;
	else
		cifsi->cifsAttrs &= (~FILE_ATTRIBUTE_SPARSE_FILE);

	return true;
}