Long delay when mounting NFS shares
Affects | Status | Importance | Assigned to | Milestone | |
---|---|---|---|---|---|
linux (Ubuntu) |
Fix Released
|
Medium
|
Unassigned | ||
Trusty |
Fix Released
|
Medium
|
Stefan Bader | ||
Utopic |
Fix Released
|
Medium
|
Unassigned |
Bug Description
SRU justification:
Impact: Kernel 3.13 shows a 16s delay when mounting NFS shares without using gssd (kerberos authentication) because it does not detect whether gssd is running at all or not.
Fix: This was fixed upstream in 3.14 by having gssd create a dummy pipe which is used as an indication of it running. Cherry-picking 3 patches from upstream gets rid of the delay.
Testcase: Trying to mount a NFS share with unix authentication will be delayed by 16s when not forcing NFSv3 protocol (using -onfsvers=3 with the mount command). After applying the patches the delay is gone.
---
Summary:
After upgrading the kernel on Ubuntu 14.04 to 3.13.0-29-generic I found that it can take a considerably longer amount of time to mount NFS shares.
How to reproduce:
1. Install Ubuntu 14.04 on two machines. A minimal server install should be fine. One will act as a server, the other as a client.
2. Upgrade the kernel on the client machine to at least 3.13.0-27-generic.
3. Install the nfs-kernel-server package on the server.
4. Add a directory to /etc/exports and run service nfs-kernel-server start.
5. Install the nfs-common package on the client.
6. Attempt to mount the shared directory on the client.
Expected result:
The shared directory should be mounted on the client more or less immediately.
Actual result:
The mount command hangs and eventually completes. In this test case it takes 16 seconds consistently. On a production machine where the problem was first discovered the time is considerably longer and essentially makes it impossible to mount NFS shares.
Regression:
I have been able to reproduce the problem on clients running Linux 3.13.0-27-generic and later. The problem is not reproducible on clients running Linux 3.13.0-24-generic. The problem is reproducible no matter which kernel version is used on the server.
Tested client kernel versions:
Linux 3.13.0-29-generic #53-Ubuntu FAIL
Linux 3.13.0-27-generic #50-Ubuntu FAIL
Linux 3.13.0-24-generic #47-Ubuntu OK
Tested server kernel versions:
Linux 3.13.0-29-generic #53-Ubuntu OK
Linux 3.13.0-27-generic #50-Ubuntu OK
Linux 3.13.0-24-generic #47-Ubuntu OK
lsb_release -rd:
Description: Ubuntu 14.04 LTS
Release: 14.04
apt-cache policy linux-image-
linux-image-
Installed: (none)
Candidate: 3.13.0.29.35
Version table:
3.13.0.29.35 0
500 http://
500 http://
3.13.0.24.28 0
500 http://
ProblemType: Bug
DistroRelease: Ubuntu 14.04
Package: linux-image-
ProcVersionSign
Uname: Linux 3.13.0-29-generic x86_64
AlsaDevices:
total 0
crw-rw---- 1 root audio 116, 1 Jun 7 16:26 seq
crw-rw---- 1 root audio 116, 33 Jun 7 16:26 timer
AplayDevices: Error: [Errno 2] No such file or directory: 'aplay'
ApportVersion: 2.14.1-0ubuntu3.2
Architecture: amd64
ArecordDevices: Error: [Errno 2] No such file or directory: 'arecord'
AudioDevicesInUse: Error: [Errno 2] No such file or directory: 'fuser'
CRDA: Error: [Errno 2] No such file or directory: 'iw'
Date: Sat Jun 7 16:30:02 2014
HibernationDevice: RESUME=
InstallationDate: Installed on 2014-06-07 (0 days ago)
InstallationMedia: Ubuntu-Server 14.04 LTS "Trusty Tahr" - Release amd64 (20140416.2)
IwConfig: Error: [Errno 2] No such file or directory: 'iwconfig'
Lsusb:
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 004 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 003 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 002 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
MachineType: QEMU Standard PC (i440FX + PIIX, 1996)
ProcFB: 0 VESA VGA
ProcKernelCmdLine: BOOT_IMAGE=
RelatedPackageV
linux-
linux-
linux-firmware N/A
RfKill: Error: [Errno 2] No such file or directory: 'rfkill'
SourcePackage: linux
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 01/01/2011
dmi.bios.vendor: Bochs
dmi.bios.version: Bochs
dmi.chassis.type: 1
dmi.chassis.vendor: Bochs
dmi.modalias: dmi:bvnBochs:
dmi.product.name: Standard PC (i440FX + PIIX, 1996)
dmi.product.
dmi.sys.vendor: QEMU
description: | updated |
summary: |
- Unable to mount NFS shares + Long timeout when mounting NFS shares |
description: | updated |
description: | updated |
summary: |
- Long timeout when mounting NFS shares + Long delay when mounting NFS shares |
tags: | added: kernel nfs regression-update |
description: | updated |
Changed in linux (Ubuntu Trusty): | |
status: | Triaged → Fix Committed |
tags: |
added: verification-done-trusty removed: verification-needed-trusty |
This change was made by a bot.