Re: [Nbd] [patch] fix "copy on write" wrong code

[Maxim Syrchin <syrchin@...62...>]

Wouter Verhelst wrote:

> > - wrong place for initialisation of diffmaps
> >    
>
> Well -- what's "wrong" is just a matter of opinion here, I'd say. It's
> both initialization code...
>
>  
At does not work before you deternine size of exported media/file. So, 
IMHO it should be moved in separate function and called later.

> > - some problem with expread (only blocksize = DIFFPAGESIZE is supported 
> > with '-c' option)
> >    
>
>  
>
> > diff -u nbd-2.8.0/nbd-server.c nbd_fix_copy_on_write/nbd-server.c
> > --- nbd-2.8.0/nbd-server.c	2005-10-19 16:36:04.858192672 +0400
> > +++ nbd_fix_copy_on_write/nbd-server.c	2005-10-19 16:38:21.296450904 +0400
> > @@ -536,7 +536,7 @@
> > 		} else { /* the block is not there */
> > 			DEBUG2("Page %Lu is not here, we read the original one\n",
> > 			       (unsigned long long)mapcnt);
> > -			return rawexpread(a, buf, rdlen, client);
> > +			if(rawexpread(a, buf, rdlen, client)) return -1;
> > 		}
> > 		len-=rdlen; a+=rdlen; buf+=rdlen;
> > 	}
> >    
>
> Hm. Do you mean that without this change, using nbd-server with -c
> doesn't support different blocksizes?
>
>  
Yes. functuin will return after reading first "page" of block. Other 
pages are not readed :(.
I've test this patch ;)