Bug 1404535

Summary: nfs-utils: /bin/ls --color=auto takes very long on dir with lots of symlinks to automounted NFS filesystems
Product: Red Hat Enterprise Linux 6 Reporter: xiaoli feng <xifeng>
Component: nfs-utilsAssignee: Steve Dickson <steved>
Status: CLOSED ERRATA QA Contact: xiaoli feng <xifeng>
Severity: unspecified Docs Contact:
Priority: medium    
Version: 6.9CC: chunwang, eguan, ikent, yoyang
Target Milestone: rcKeywords: Regression
Target Release: ---   
Hardware: Unspecified   
OS: Unspecified   
Whiteboard:
Fixed In Version: nfs-utils-1.2.3-75.el6 Doc Type: If docs needed, set a value
Doc Text:
Story Points: ---
Clone Of: Environment:
Last Closed: 2017-03-21 11:24:24 UTC Type: Bug
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Bug Depends On:    
Bug Blocks: 1401884    

Description xiaoli feng 2016-12-14 03:59:08 UTC 
Description of problem:
It is a clone bug from https://bugzilla.redhat.com/show_bug.cgi?id=787595


Running "/bin/ls --color=auto" on  directory with a large amount of symlinks to automounted NFS filesystems takes over 10 minutes, whereas the same command runs in less than 2 seconds on an identically configured RHEL5.7 system.
Running "top" while the "ls" is running shows that for each symlink the system tries to mount the linked NFS filesystem, but since some of the NFS servers listed in the automount map aren't available some of the mounts hang until the timeout is reached.


It is a regression issue. It had been fixed in RHEL6.1. But now have this issue on nfs-utils-1.2.3-73.el6.x86_64.rpm


Test on nfs-utils-1.2.3-71.el6.x86_64.rpm:

[06:14:15 root@ ~~]# time /bin/ls --color=auto /mnt/${TESTNAME}/* 

/mnt/bz787595/bin
/mnt/bz787595/man

/mnt/bz787595/etc:

/mnt/bz787595/lib:

real	1m26.434s
user	0m0.000s
sys	0m0.004s


Tested on nfs-utils-1.2.3-73.el6.x86_64.rpm:

[06:23:15 root@ ~~]# time /bin/ls --color=auto /mnt/${TESTNAME}/* 

/mnt/bz787595/bin
/mnt/bz787595/man

/mnt/bz787595/etc:

/mnt/bz787595/lib:

real	6m18.493s
user	0m0.000s
sys	0m0.006s

Version-Release number of selected component (if applicable):
nfs-utils-1.2.3-73.el6.x86_64.rpm

How reproducible:
100%

Steps to Reproduce:
1. verify that automounter is running
2. run "/bin/ls --color=auto" on dir with symlinks to automounted NFS filesystems 
3. wait a long time for output

Actual results:
"/bin/ls --color=auto /mnt/${TESTNAME}/*" need about 6 minute

Expected results:

"/bin/ls --color=auto /mnt/${TESTNAME}/*" need about 1 minute

Additional info:
Comment 1 Ian Kent 2016-12-14 11:23:10 UTC 
Steve,

I've worked out what's happening here, please have a look at
comments #26 and #27 of bug 1350786.

I need "mount.nfs -V" to work, I'd appreciate it very much if
you could fix it in revision 73. There might not be a lot that
can be done about the delay we see attempting nfs mounts to
servers that aren't available.

Ian
Comment 9 errata-xmlrpc 2017-03-21 11:24:24 UTC 
Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory, and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

https://rhn.redhat.com/errata/RHBA-2017-0741.html