Date: Tue, 11 Oct 2011 15:07:13 GMT From: George Breahna <george@polarismail.com> To: freebsd-gnats-submit@FreeBSD.org Subject: amd64/161493: NFS v3 directory structure update slow Message-ID: <201110111507.p9BF7Dqw036762@red.freebsd.org> Resent-Message-ID: <201110111510.p9BFA7k7025728@freefall.freebsd.org>
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>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@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:
>Release-Note:
>Audit-Trail:
>Unformatted:
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