Re: Occassional "permission denied" in the middle of a large transfer over NFS

Just a note to say I have tested this on -CURRENT with the new nfs
server and it is still the case.

On the client (FreeBSD seaurchin 8.3-RELEASE-p3 FreeBSD 8.3-RELEASE-p3
#0: Tue Jun 12 00:39:29 UTC 2012    
root_at_amd64-builder.daemonology.net:/usr/obj/usr/src/sys/GENERIC  amd64)

[root_at_seaurchin /mnt/nfs/vm]# date ; tar -cf foo.tar 
/var/nfsen/profiles-data/ ; date
Thu Jun 28 20:12:36 BST 2012
tar: Removing leading '/' from member names
tar: Write error
Thu Jun 28 20:12:38 BST 2012
[root_at_seaurchin /mnt/nfs/vm]#



on the Server
[root_at_fbsd /var/tmp]# uname -a ; date ; while true ; do mount /dev/md0
/mnt/tmp/ ; umount /mnt/tmp ; done
FreeBSD fbsd 10.0-CURRENT FreeBSD 10.0-CURRENT #22 r237646: Wed Jun 27
19:13:26 BST 2012    
toor_at_fbsd.bmk.namesco.net:/usr/obj/usr/src/sys/unsane-vm  amd64
Thu Jun 28 20:12:38 BST 2012
^C
[root_at_fbsd /var/tmp]#

any suggestions welcome.

Vince


On 27/06/2012 16:27, Vincent Hoffman wrote:
> Hi,
> After only one off-list reply from the author of kern/136865 (see below)
> after asking -questions, I thought it worth asking -CURRENT.
> Basically:
>
> I seem to have run into the problems described in this old thread.
> http://lists.freebsd.org/pipermail/freebsd-questions/2004-April/044927.html
>
> tl:dr mountd may give incorrect permission denied errors when it is
> refreshing the exports list due to non-atomic operations,  /sbin/mount has code that sends SIGHUP to
> mountd on any mount operation, which implies that any manual mount
> request would cause the problem.  
>
> Currently I have still only tested on 8.3-RELEASE but the svn log doesnt
> seem to mention a fix since then. I'm currently taking a VM up to
> -CURRENT to test.
>
> Looking though old PRs I see the following related.
> kern/131342
> kern/136865 (with patch for 7.2 and links to
> http://nfse.sourceforge.net/ for -CURRENT )
>
> Does anyone who is qualified (sadly not me) feel like looking at the
> code to see if its suitable for inclusion in part/whole as not having
> NFS transfers interrupted by local mount operations on the nfs server
> would be very handy :)
>
>
> thanks, Vince
>
>
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