[OpenAFS] tsmafs utility: rx_Read() returns 0?

Wed, 17 Apr 2013 00:09:54 -0400

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I don't have the appropriate context because I don't know what RPC the
code in question is executing but the 1.4.10 file server does have a bug
which can result in rx_Read() returning 0 octets to the first data read
as part of an FetchData response which is not an indication of end of
file or an error.

On 4/16/2013 9:55 PM, Robert Sturrock wrote:
> Hi All.
>=20
> (I'm not sure if this should go to openafs-info, or the devel list, so =
I apologise if I've gotten that wrong).
>=20
> We are using a small utility here, written by the good people at ltu.se=
, to backup our OpenAFS cell to TSM.  The tool is "tsmafs" (/afs/ltu.se/m=
isc/tsmafs/tsmafs-0.2.tgz), which includes a program called "tabackup" to=
 perform the actual backup.  We found what we believe is a bug, in which =
rx_Read() is used to read data from AFS, but the scenario where this retu=
rns 0 bytes is not checked.
>=20
> The outcome of this is that the tool would occasionally read 0 bytes an=
d then continue on, assuming that it had successfully backed up the file =
in question, leaving perhaps only a fragment of the file on TSM.
>=20
> The code _was_ originally as follows (tabackup.c:storefile():322):
>=20
>                if ((b =3D rx_Read(rxc, buf, len)) < 0)
>                         break;
>=20
> .. so we added the following extra sanity checking to detect this and r=
aise an error:
>=20
> +                if (b =3D=3D 0)
> +                {
> +                   rx_error_code =3D rx_Error(rxc);
> +                   warnx("zero length rx_Read for %s%s", hl, ll);
> +                   warnx("rx error (%ld) tsn (%lld) tsz (%lld) len (%d=
)", rx_error_code, tsn, tsz, len);
> +                   break;
> +                }
>=20
> I suppose my question is: is it normal/ok for rx_Read() to return 0, or=
 is this in itself indicative of a problem or bug somewhere?
>=20
> We are running OpenAFS 1.4.12-1.1.2 on the (RHEL5) client.  Fileserver =
is 1.4.10 on Solaris-x86.
>=20
> Any pointers appreciated ...
>=20
> Regards,
>=20
> Robert.
> _______________________________________________
> OpenAFS-info mailing list
> OpenAFS-info@openafs.org
> https://lists.openafs.org/mailman/listinfo/openafs-info
>=20

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