INT21,7305 only invalidates buffers on success

[boeckmann]

I think the buffers should also invalidated in case of failure, as there may have been partial multi-sector writes despite failure is returned?!?

kernel/kernel/inthndlr.c

Lines 401 to 407 in 8535ddb

	r->AX =
	dskxfer(r->DL - 1, SectorBlock->blkno, SectorBlock->buf,
	SectorBlock->nblks, mode);
	if (mode == DSKWRITEINT26)
	if (r->AX == 0)
	setinvld(r->DL - 1);

Interestingly, for INT25,26 the logic is negated: buffers only invalidated on failure:

kernel/kernel/inthndlr.c

Lines 1858 to 1866 in 8535ddb

	r->ax = dskxfer(drv, blkno, buf, nblks, mode);
	CLEAR_CARRY_FLAG();
	if (r->ax != 0)
	{
	SET_CARRY_FLAG();
	if (mode == DSKWRITEINT26)
	setinvld(drv);
	}

Though there is a buffer invalidate a few lines above introduced by me:

kernel/kernel/inthndlr.c

Lines 1856 to 1857 in 8535ddb

	if (mode == DSKWRITEINT26)
	DeleteBlockInBufferCache(blkno, blkno, drv, XFR_WRITE);

but this contains an error by only invalidating the first buffer of a potential multi-sector write.