Re: [9fans] Disk backup?

[arisawa <arisawa@ar.aichi-u.ac.jp>]

oh! nice!
that resolves all.
thanks a lot
i will try

On 2013/03/25, at 16:19, cinap_lenrek@gmx.de wrote:

> the block bitmap on a fakeworm is at the end of the sub
> device/partition. see fworm.c:
>
> int
> fwormread(Device *d, Off b, void *c)
> {
> 	Iobuf *p;
> 	Device *fdev;
> 	Devsize l;
>
> 	if(chatty > 1)
> 		fprint(2, "fworm read  %lld\n", (Wideoff)b);
> 	fdev = FDEV(d);
> 	l = devsize(fdev);
> 	l -= l/(BUFSIZE*8) + 1;
> 	if(b >= l)
> 		panic("fworm: rbounds %lld", (Wideoff)b);
> 	l += b/(BUFSIZE*8);
>
> 	p = getbuf(fdev, l, Brd|Bres);
> 	if(!p || checktag(p, Tvirgo, l))
> 		panic("fworm: checktag %lld", (Wideoff)l);
> 	l = b % (BUFSIZE*8);
> 	if(!(p->iobuf[l/8] & (1<<(l%8)))) {
> 		putbuf(p);
> 		fprint(2, "fworm: read %lld\n", (Wideoff)b);
> 		return 1;
> 	}
> 	putbuf(p);
> 	return devread(fdev, b, c);
> }
>
> the block tags do not really matter for the backup. you use the
> fakeworm only as a backend for the cw device so you can just
> copy all the blocks that got ther bit set in the bitmap compared
> to the backup.
>
> --
> cinap
>