amd64/161493: NFS v3 directory structure update slow
George Breahna
george at polarismail.com
Thu Oct 13 02:10:12 UTC 2011
The following reply was made to PR kern/161493; it has been noted by GNATS.
From: "George Breahna" <george at polarismail.com>
To: "'John Baldwin'" <jhb at freebsd.org>,
<freebsd-amd64 at freebsd.org>
Cc: <freebsd-gnats-submit at freebsd.org>,
"'Rick Macklem'" <rmacklem at freebsd.org>
Subject: RE: amd64/161493: NFS v3 directory structure update slow
Date: Wed, 12 Oct 2011 21:41:34 -0400
I can also confirm that using -o option in nfsd makes the problem go away.
George
-----Original Message-----
From: John Baldwin [mailto:jhb at freebsd.org]
Sent: Wednesday, October 12, 2011 9:30 AM
To: freebsd-amd64 at freebsd.org
Cc: George Breahna; freebsd-gnats-submit at freebsd.org; Rick Macklem
Subject: Re: amd64/161493: NFS v3 directory structure update slow
On Tuesday, October 11, 2011 11:07:13 am George Breahna wrote:
>
> >Number: 161493
> >Category: amd64
> >Synopsis: NFS v3 directory structure update slow
> >Confidential: no
> >Severity: critical
> >Priority: high
> >Responsible: freebsd-amd64
> >State: open
> >Quarter:
> >Keywords:
> >Date-Required:
> >Class: sw-bug
> >Submitter-Id: current-users
> >Arrival-Date: Tue Oct 11 15:10:07 UTC 2011
> >Closed-Date:
> >Last-Modified:
> >Originator: George Breahna
> >Release: 9.0 Beta 2
> >Organization:
> >Environment:
> FreeBSD store2 9.0-BETA2 FreeBSD 9.0-BETA2 #0: Sun Sep 18 22:02:45 EDT
2011
pulsar at store2.emailarray.com:/usr/obj/usr/src/sys/PULSAR amd64
> >Description:
> We used to run a NFS server on FreeBSD 6.2 but we built a new box recently
and installed 9.0 Beta 2 on it. The data was moved over as it serves as the
back-end for a mail system. It runs NFS v3 over TCP only and all the NFS-
related processes (rpcbind, mountd, lockd, etc ) run with the -h switch and
bind to the local IP address.
>
> The NFS server exports the data to 7 NFS clients ranging from FreeBSD 6.1
to
8.2, the majority being 8.2 The mount on the NFS clients is done simply with
-
o tcp,rsize=32768,wsize=32768
>
> Usual file operations, such as accessing files, creating directories,
removing files, chmod, chown, etc work perfectly but we noticed there were
issues in removing directories that contained data. We had a strange error:
>
> rm -rf nick/
> rm: fts_read: Input/output error
>
> Using 'truss' on rm revealed this:
>
> open("..",O_RDONLY,00) ERR#5 'Input/output
error'
>
> After much testing and debugging we realized the problem is in the NFS
protocol. ( either server or client but we assume server since this used to
work very well with FreeBSD 6.2 ). The problem appears to be that NFS does
not
show the '..' after modifying a directory structure. Take the following
example executed on a FreeBSD 8.2 client accessing the NFS share from the
9.0B2 server:
>
> imap5# mkdir test1
> imap5# cd test1
> imap5# touch file1
> imap5# touch file2
> imap5# ls -la
> ls: ..: Input/output error
> total 4
> drwxr-xr-x 2 root vchkpw 512 Oct 11 10:55 .
> -rw-r--r-- 1 root vchkpw 0 Oct 11 10:55 file1
> -rw-r--r-- 1 root vchkpw 0 Oct 11 10:55 file2
>
> Notice the '..' is missing from the display. If we now try and remove the
directory 'test1' it will throw the "rm: fts_read: Input/output error"
error.
>
> If we wait in between 1 minute and 5 minutes, '..' will eventually appear
by
itself. During this whole time, '..' effectively exists on the NFS server
but
it's not displayed by any of the NFS clients.
>
> I can force the NFS client to show it faster by doing an ls -la from the
parent level. For example:
>
> imap5# mkdir test1
> imap5# touch test1/file1
> imap5# touch test1/file2
> imap5# touch test1/file3
> imap5# ls -la test1
> total 8
> drwxr-xr-x 2 root vchkpw 512 Oct 11 10:59 .
> drwx------ 10 vpopmail vchkpw 1024 Oct 11 10:59 ..
> -rw-r--r-- 1 root vchkpw 0 Oct 11 10:59 file1
> -rw-r--r-- 1 root vchkpw 0 Oct 11 10:59 file2
> -rw-r--r-- 1 root vchkpw 0 Oct 11 10:59 file3
> imap5# cd test1
> imap5# ls -la
> total 8
> drwxr-xr-x 2 root vchkpw 512 Oct 11 10:59 .
> drwx------ 10 vpopmail vchkpw 1024 Oct 11 10:59 ..
> -rw-r--r-- 1 root vchkpw 0 Oct 11 10:59 file1
> -rw-r--r-- 1 root vchkpw 0 Oct 11 10:59 file2
> -rw-r--r-- 1 root vchkpw 0 Oct 11 10:59 file3
>
> but if we wait 5 seconds after that display and try again:
>
> ls -la
> ls: ..: Input/output error
> total 4
> drwxr-xr-x 2 root vchkpw 512 Oct 11 10:59 .
> -rw-r--r-- 1 root vchkpw 0 Oct 11 10:59 file1
> -rw-r--r-- 1 root vchkpw 0 Oct 11 10:59 file2
> -rw-r--r-- 1 root vchkpw 0 Oct 11 10:59 file3
>
> Again, if we wait longer ( 1-5 minutes ), the '..' will properly appear in
there.
>
> There are no error messages on the console or other log files. This is
reproducible 100% of the time with any FreeBSD client. Have tried
unmounting/remounting several times without any effect. Also tried different
rsize/wsize, no effect. I think there is some delay in updating the
directory
structure and it's causing this bug.
>
> Here's also some output from nfsstat on the server:
>
>
> Server Info:
> Getattr Setattr Lookup Readlink Read Write Create
Remove
> 114731225 20496896 254966151 133 11697392 19963641 0
9228861
> Rename Link Symlink Mkdir Rmdir Readdir RdirPlus
Access
> 4313471 1157651 39 1955 16511932 15479669 0
116927742
> Mknod Fsstat Fsinfo PathConf Commit
> 0 4748487 48 0 14921747
> Server Ret-Failed
> 0
> Server Faults
> 0
> Server Cache Stats:
> Inprog Idem Non-idem Misses
> 0 0 0 613368147
> Server Write Gathering:
> WriteOps WriteRPC Opsaved
> 19963641 19963641 0
>
> >How-To-Repeat:
> imap5# mkdir test1
> imap5# cd test1
> imap5# touch file1
> imap5# touch file2
> imap5# ls -la
> ls: ..: Input/output error
> total 4
> drwxr-xr-x 2 root vchkpw 512 Oct 11 10:55 .
> -rw-r--r-- 1 root vchkpw 0 Oct 11 10:55 file1
> -rw-r--r-- 1 root vchkpw 0 Oct 11 10:55 file2
> >Fix:
Can you try using the "old" NFS server as a test?
--
John Baldwin
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