Hi,
we have some user reporting that NFS v3 mounts are broken
when using glibc-2.29 and linux-4.9.x (4.9.128) because
statx() with mask=STATX_BASIC_STATS returns EINVAL.
Looks like this isn't happening with <nfs-utils-2.4.1 or
newer kernels.
The following workaround was confirmed to be working:
--- a/support/misc/xstat.c 2019-06-24 21:31:55.260371592 +0200
+++ b/support/misc/xstat.c 2019-06-24 21:32:29.098777436 +0200
@@ -47,6 +47,8 @@
statx_copy(statbuf, &stxbuf);
return 0;
}
+ if (errno == EINVAL)
+ errno = ENOSYS;
if (errno == ENOSYS)
statx_supported = 0;
} else
Bug: https://bugs.gentoo.org/688644
At the moment I have no clue whether this is kernel/glibc or
nfs-utils related; if the patch is safe to apply...
Any help is appreciated. Thanks!
--
Regards,
Thomas Deutschmann / Gentoo Linux Developer
C4DD 695F A713 8F24 2AA1 5638 5849 7EE5 1D5D 74A5
On Tue, Oct 08, 2019 at 10:23:56PM +0200, Thomas Deutschmann wrote:
> Hi,
>
> we have some user reporting that NFS v3 mounts are broken
> when using glibc-2.29 and linux-4.9.x (4.9.128) because
> statx() with mask=STATX_BASIC_STATS returns EINVAL.
>
> Looks like this isn't happening with <nfs-utils-2.4.1 or
> newer kernels.
>
> The following workaround was confirmed to be working:
>
> --- a/support/misc/xstat.c 2019-06-24 21:31:55.260371592 +0200
> +++ b/support/misc/xstat.c 2019-06-24 21:32:29.098777436 +0200
> @@ -47,6 +47,8 @@
> statx_copy(statbuf, &stxbuf);
> return 0;
> }
> + if (errno == EINVAL)
> + errno = ENOSYS;
> if (errno == ENOSYS)
> statx_supported = 0;
> } else
>
>
> Bug: https://bugs.gentoo.org/688644
>
> At the moment I have no clue whether this is kernel/glibc or
> nfs-utils related; if the patch is safe to apply...
Well, sounds like nfs-utils started using statx in 2.4.1. And just the
fact that varying the kernel version makes it sound like there was a
kernel bug causing an EINVAL return in this case, and that bug got
fixed.
One way to confirm might be running mount under strace and looking for
that EINVAL return.
I might also try looking through the kernel logs for nfs or the stat
code to see if there's a mention of this (didn't see it on a quick
look.) Or try bisecting kernel versions to find the one where this was
fixed.
--b.
>
> Any help is appreciated. Thanks!
>
>
> --
> Regards,
> Thomas Deutschmann / Gentoo Linux Developer
> C4DD 695F A713 8F24 2AA1 5638 5849 7EE5 1D5D 74A5
>
On Fri, Oct 11, 2019 at 17:07:09PM +0000, Bruce Fields wrote:
>On Tue, Oct 08, 2019 at 10:23:56PM +0200, Thomas Deutschmann wrote:
>> Hi,
>>
>> we have some user reporting that NFS v3 mounts are broken
>> when using glibc-2.29 and linux-4.9.x (4.9.128) because
>> statx() with mask=STATX_BASIC_STATS returns EINVAL.
>>
>> Looks like this isn't happening with <nfs-utils-2.4.1 or
>> newer kernels.
>>
>> The following workaround was confirmed to be working:
>>
>> --- a/support/misc/xstat.c 2019-06-24 21:31:55.260371592 +0200
>> +++ b/support/misc/xstat.c 2019-06-24 21:32:29.098777436 +0200
>> @@ -47,6 +47,8 @@
>> statx_copy(statbuf, &stxbuf);
>> return 0;
>> }
>> + if (errno == EINVAL)
>> + errno = ENOSYS;
>> if (errno == ENOSYS)
>> statx_supported = 0;
>> } else
>>
>>
>> Bug: https://bugs.gentoo.org/688644
>>
>> At the moment I have no clue whether this is kernel/glibc or
>> nfs-utils related; if the patch is safe to apply...
>
>Well, sounds like nfs-utils started using statx in 2.4.1. And just the
>fact that varying the kernel version makes it sound like there was a
>kernel bug causing an EINVAL return in this case, and that bug got
>fixed.
>
>One way to confirm might be running mount under strace and looking for
>that EINVAL return.
Just to provide an update on this issue, it was tracked down to glibc's
statx emulation not supporting AT_STATX_DONT_SYNC and returning EINVAL.
So on a kernel without statx support, but a new glibc with statx
support, nfs-utils will always fail to stat any paths.
Either this or a similar fix is required to support older kernels.
Doug
On Tue, Nov 26, 2019 at 02:22:40AM -0500, Doug Nazar wrote:
> On Fri, Oct 11, 2019 at 17:07:09PM +0000, Bruce Fields wrote:
> >On Tue, Oct 08, 2019 at 10:23:56PM +0200, Thomas Deutschmann wrote:
> >> Hi,
> >>
> >> we have some user reporting that NFS v3 mounts are broken
> >> when using glibc-2.29 and linux-4.9.x (4.9.128) because
> >> statx() with mask=STATX_BASIC_STATS returns EINVAL.
> >>
> >> Looks like this isn't happening with <nfs-utils-2.4.1 or
> >> newer kernels.
> >>
> >> The following workaround was confirmed to be working:
> >>
> >> --- a/support/misc/xstat.c??? 2019-06-24 21:31:55.260371592 +0200
> >> +++ b/support/misc/xstat.c??? 2019-06-24 21:32:29.098777436 +0200
> >> @@ -47,6 +47,8 @@
> >>? ??? ??? ??? statx_copy(statbuf, &stxbuf);
> >>? ??? ??? ??? return 0;
> >>? ??? ??? }
> >> +??? ??? if (errno == EINVAL)
> >> +??? ??? ??? errno = ENOSYS;
> >>? ??? ??? if (errno == ENOSYS)
> >>? ??? ??? ??? statx_supported = 0;
> >>? ??? } else
> >>
> >>
> >> Bug: https://bugs.gentoo.org/688644
> >>
> >> At the moment I have no clue whether this is kernel/glibc or
> >> nfs-utils related; if the patch is safe to apply...
> >
> >Well, sounds like nfs-utils started using statx in 2.4.1.? And just the
> >fact that varying the kernel version makes it sound like there was a
> >kernel bug causing an EINVAL return in this case, and that bug got
> >fixed.
> >
> >One way to confirm might be running mount under strace and looking for
> >that EINVAL return.
>
> Just to provide an update on this issue, it was tracked down to glibc's
> statx emulation not supporting AT_STATX_DONT_SYNC and returning EINVAL.
>
> So on a kernel without statx support, but a new glibc with statx support,
> nfs-utils will always fail to stat any paths.
>
> Either this or a similar fix is required to support older kernels.
OK. So maybe your patch is the best we can do. I'd just add a comment
there documenting the situation.
--b.