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

[Kinsbursky Stanislav <skinsbursky@parallels.com>]

03.12.2010 21:17, Chuck Lever пишет:
>
> On Dec 3, 2010, at 1:01 PM, Kinsbursky Stanislav wrote:
>
>> 03.12.2010 20:35, Chuck Lever пишет:
>>>
>>> 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".
>
> Right: zero and negative one are both special internal port values that should not be displayed in /proc/mounts.  Why not check if mountport>  0 instead?
>

Yep, you right. I'll sent second version.

>> 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().
>
> I'm not sure I follow here.  Why would setting nfsport be the right thing to do?  The default case is for text-based mounts only.
>
>> Kernel version affected: 2.6.37-rc4
>>>>
>>>> Signed-off-by: Stanislav Kinsbursky<skinsbursky@parallels.com>
>>>>
>>>> ---
>>>> 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);
>>>>
>>>> --
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>>>
>>
>>
>> --
>> Best regards,
>> Stanislav Kinsbursky
>


-- 
Best regards,
Stanislav Kinsbursky