[9fans] kfs bug

[9fans] kfs bug

[rod]

kfs works fine for a bit and then fails with an "out of files" error.

It happens when the fid in a 9p message gets to a value greater than
32767. I think the "fid" field in struct File should be a 32-bit type
rather than a short int.

Would I be right in thinking that 9p originally had 16 bit fids? If
so, it suggests that no-one has used kfs in anger for a while.

Rod

Re: [9fans] kfs bug

[Charles Forsyth]

>Would I be right in thinking that 9p originally had 16 bit fids? If
>so, it suggests that no-one has used kfs in anger for a while.

how are you using the kfs? just locally?
a plan 9 client normally re-used fids, so i'd have thought you'd need to have >32767 active files,
which most people probably haven't done.

mind you, that reminds me that i'd noticed something odd when looking at 9p
traces earlier in the summer, which i'd failed to note to track down later
(unless i did work it out and decided there wasn't a problem).

Re: [9fans] kfs bug

[rod]

>a plan 9 client normally re-used fids,

Ah right, thank you - I see that now. I have just tried native plan9
and, of course, it works fine. I was running 9vx earlier and it
seems as if the fid increments each time.

Rod

Re: [9fans] kfs bug

[erik quanstrom]

On Thu Sep  9 09:54:56 EDT 2010, forsyth@terzarima.net wrote:
> >Would I be right in thinking that 9p originally had 16 bit fids? If
> >so, it suggests that no-one has used kfs in anger for a while.
>
> how are you using the kfs? just locally?
> a plan 9 client normally re-used fids, so i'd have thought you'd need to have >32767 active files,
> which most people probably haven't done.

changing File->fid to ulong should be good enough.
i haven't had any trouble in testing on arm.

one could argue for u32int, but the rest of kfs doesn't
use u32int either and i didn't track down all the places
where fid is passed in an int anyway.

diff -c /n/dump/2010/0909/sys/src/cmd/disk/kfs/portdat.h portdat.h
/n/dump/2010/0909/sys/src/cmd/disk/kfs/portdat.h:150,156 - portdat.h:150,156
  	long	addr;
  	long	slot;
  	long	lastra;		/* read ahead address */
- 	short	fid;
+ 	ulong	fid;
  	short	uid;
  	char	open;
  		#define	FREAD	1
diff -c /n/dump/2010/0909/sys/src/cmd/disk/kfs/sub.c sub.c
/n/dump/2010/0909/sys/src/cmd/disk/kfs/sub.c:89,95 - sub.c:89,95
  			goto out;
  		}
  	}
- else print("cannot find %p.%d (list=%p)\n", cp, fid, cp->flist);
+ else print("cannot find %p.%ud (list=%p)\n", cp, fid, cp->flist);
  	unlock(&cp->flock);
  	return 0;

- erik