[Pvfs2-developers] RHEL4 and 2.7.1 mount problems

[Phil Carns]

Here is an updated version that catches the other stray cases like 
perf-counters/acache.  It also corrects that warning message about inode 
allocations.

-Phil

Bart Taylor wrote:
> Thanks Phil, that patch works great! I successfully ran the previous 
> script on a few thousand mounts and did not have any more problems.
> 
> It looks like you nailed down where the problem lies even if it isn't 
> fixed in every case. I ran the 'for' loop you mentioned that bounces off 
> the acache perf-counter just to see what would happen, and it still 
> causes a hang as I think you expected.
> 
> Bart.
> 
> 
> 
> On Tue, May 13, 2008 at 7:55 AM, Phil Carns <carns at mcs.anl.gov 
> <mailto:carns at mcs.anl.gov>> wrote:
> 
>     Hi Bart,
> 
>     Could you try this patch out and see if it fixes your problem?  This
>     is checked into trunk as well.  This won't eliminate the inode alloc
>     warning, but I think it does actually fix the umount hang.
> 
>     I also suspect that this same issue may affect a few other cases as
>     well, but it would be good if you could confirm this much for starters.
> 
>     I think the same class of bug is affecting some of the proc file
>     handlers, for example.  Cases like this also cause a
>     pvfs2-client-core hang:
> 
>     "for i in `seq 1 100`; do echo $i; cat
>     /proc/sys/pvfs2/perf-counters/acache; done"
> 
>     thanks!
>     -Phil
> 
>     Bart Taylor wrote:
> 
>         Hey guys,
> 
>         I have been running some tests against the 271 release, and I am
>         having some trouble with multiple mounts on one client.  My
>         setup has 2 servers (both meta and io servers on local disk) and
>         one client all of which are running RHEL4 update 6. All that was
>         done on the test client is loading the kernel module and
>         starting pvfs2-client.  I can mount the file system once and use
>         it without any problem, but I have attached a test script -
>         takes file system information and a number of times to mount it
>         - that keeps failing.  Here are the steps it executes:
> 
>         - For the number of mounts requested
>           - Create a new directory (defaults to /tmp/mount_limit.#)
>           - Mount the specified file system on the new dir
> 
>         - For the number of mounts requested
>           - Do a recursive ls comparison (keep a copy the first time
>         through and compare subsequent mounts to the first)
>           - Unmount the dir
>           - Delete the dir
> 
>         I have been able to consistently reproduce the problem running
>         the attached script like this:
>         ./test-mount-limit.pl pvfs2-server1:3334/pvfs2-fs 100
>         It stalls every time with either 36 or 37 mounts remaining.  The
>         script has been successfully run on previous versions of pvfs2
>         up to several thousand mounts.
> 
>         The problem comes at the umount step.  Eventually the process
>         just hangs, strands a bunch of mounts, and umount doesn't work
>         as expected after that even from the command line.  When it
>         stalls, I start seeing messages like this one in dmesg and syslog:
>         May  2 15:02:44 client-node kernel: pvfs2_kill_sb: (WARNING)
>         number of inode allocs (4100) != number of inode deallocs (2665)
> 
>         I am running this against an almost empty file system since the
>         recursive ls would take a while if it were large. Am I doing
>         something wrong/strange here, or is there a client/kernel
>         problem? The test seems pretty straight-forward, and I've never
>         had an issue with the script before. I'm not sure if it was run
>         against the 2.7.0 release though.
> 
>         Bart.
> 
> 
>         ------------------------------------------------------------------------
> 
> 
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> 
> 
> 

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