[Pvfs2-developers] RHEL4 and 2.7.1 mount problems

[Phil Carns]

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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