Re: [PATCH] NFS: suppressing showing of default mount port valuein /proc fixed

[Kinsbursky Stanislav]

03.12.2010 20:35, Chuck Lever ÐÐÑÐÑ:
> On Dec 3, 2010, at 12:11 PM, Stanislav Kinsbursky wrote:
>
> > Default value for mount server port is set to NFS_UNSPEC_PORT (-1) and will not
> > be changed during parsing mount options for mound data version 6. This default
> > value will be showed for mountport in /proc/mounts always since current default
> > check is for zero value. This small mistake leads to big problem, because
> > during umount.nfs execution from old user-space utils (at least nfs-utils
> > 1.0.9) this value will be used as the server port to connect to. This request
> > will be rejected (since port is 65535) and thus nfs mount point can't be
> > unmounted.
>
> Note: this is only possible if /etc/mtab is a link to /proc/mounts.  Not all systems have this configuration.

I found it on CentOs 5.5 with RHEL6 kernel.
Actually, the current patch has a specific flaw: if mount port is not passed by nfs utils using mount options version 6, then it will be set to 0 and showed in /proc/mounts as "mountport=0".
Another fix solution is to call "nfs_set_port(sap, &args->nfs_server.port, 0);" when parsing mount options version 6 (like in done in default casein nfs_validate_mount_data) instead of changing 
nfs_show_mountd_options().


> > Kernel version affected: 2.6.37-rc4
> >
> > Signed-off-by: Stanislav Kinsbursky<skinsbursky@xxxxxxxxxxxxx>
> >
> > ---
> > fs/nfs/super.c |    3 ++-
> > 1 files changed, 2 insertions(+), 1 deletions(-)
> >
> > diff --git a/fs/nfs/super.c b/fs/nfs/super.c
> > index 6d6e21d..fd4cac8 100644
> > --- a/fs/nfs/super.c
> > +++ b/fs/nfs/super.c
> > @@ -681,7 +681,8 @@ static void nfs_show_mountd_options(struct seq_file *m, struct nfs_server *nfss,
> >
> > 	if (nfss->mountd_version || showdefaults)
> > 		seq_printf(m, ",mountvers=%u", nfss->mountd_version);
> > -	if (nfss->mountd_port || showdefaults)
> > +	if (nfss->mountd_port != (unsigned short)NFS_UNSPEC_PORT ||
> > +			showdefaults)
> > 		seq_printf(m, ",mountport=%u", nfss->mountd_port);
> >
> > 	nfs_show_mountd_netid(m, nfss, showdefaults);
> >
> > --
> > To unsubscribe from this list: send the line "unsubscribe linux-nfs" in
> > the body of a message to majordomo@xxxxxxxxxxxxxxx
> > More majordomo info at  http://vger.kernel.org/majordomo-info.html


--
Best regards,
Stanislav Kinsbursky
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/