maindavfs2 - Support: sr #108765, does davfs have issues with IPC?

 
 

sr #108765: does davfs have issues with IPC?

Submitter:  Jason Haar <jhaar>
Submitted:  Tue 10 Mar 2015 03:20:19 AM UTC
   
 
Category:  None Priority:  5 - Normal
Severity:  3 - Normal Status:  In Progress
Privacy:  Public Assigned to:  _71007
Open/Closed:  Closed Operating System:  GNU/Linux
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Wed 11 Mar 2015 04:21:56 PM UTC, comment #1: 

davfs2 has nothing to do with IPC. All these semget, semop, shmget and semctl syscalls happen between your application and the kernel wtihout davfs2 beeing involved.

Concerning davfs2:
Assuming that /var/lib/avast4/400.vps is on your davfs2 file system. I see two successful calls of stat64 and one call of open that is interupted.
I don't know why strace is interupted during the pending call of open; probably because it seemed to hang.

You can get more information about what happens when open is called:
- add option 'debug most' to your davfs2.conf file
- search your log files for messages from mount.davfs (there will be a lot)
- you may analyse them by yourself or send them here.

Please note:
When a file is opened then davfs2 usually has to do at least one HTTP request (maybe more than one) and if the proper version of the file is not in the cache it will have to download the file.
Downloading a 16-MB-file may take some time, depending on the quality of the connection. If the connection is broken it may take several timeout times before davfs2 can respond to the open call.

Werner

P.S.:
As your application is 32 bit and works on a 32 bit OS but fails on a 64 bit OS I would first look for general interoperability issues between your application and the operating system.

- <_71007>
Tue 10 Mar 2015 03:20:19 AM UTC, original submission:  

Hi there

I'm trying to run the Avast AV command line client off a davfs share and it hangs.. strace shows it ends as below.

I assume what is happening is Avast assumes certain file system characteristics are present when they are not (sorry I'm not a programmer, running strace and pointing is about my limit ;-)

The weird thing is this works on a CentOS-6/32bit client (running mount.davfs), but doesn't work on either CentOS-6/64bit or Ubuntu-14.04/64bit

Is this something "fixable", or is this something 64bit related? The avast package is 32bit if that matters. The "/var/lib/avast4/400.vps" file is on the davfs share BTW

Thanks!

[pid  4535] sched_get_priority_min(SCHED_OTHER <unfinished ...>
[pid  4534] futex(0x9c160f0, FUTEX_WAKE_PRIVATE, 1 <unfinished ...>
[pid  4535] <... sched_get_priority_min resumed> ) = 0
[pid  4534] <... futex resumed> )       = 0
[pid  4535] sched_get_priority_max(SCHED_OTHER) = 0
[pid  4534] stat64("/var/lib/avast4/400.vps",  <unfinished ...>
[pid  4535] sched_setscheduler(4535, SCHED_OTHER, { 0 } <unfinished ...>
[pid  4534] <... stat64 resumed> {st_mode=S_IFREG|0644, st_size=163012739, ...}) = 0
[pid  4535] <... sched_setscheduler resumed> ) = 0
[pid  4534] getuid32( <unfinished ...>
[pid  4535] semop(1966086, {{2, 0, IPC_NOWAIT}}, 1 <unfinished ...>
[pid  4534] <... getuid32 resumed> )    = 0
[pid  4535] <... semop resumed> )       = -1 EAGAIN (Resource temporarily unavailable)
[pid  4534] stat64("/var/lib/avast4/400.vps",  <unfinished ...>
[pid  4535] nanosleep({1, 500000000},  <unfinished ...>
[pid  4534] <... stat64 resumed> {st_mode=S_IFREG|0644, st_size=163012739, ...}) = 0
[pid  4534] semget(0x50260fa0, 3, IPC_CREAT|IPC_EXCL|0600) = -1 EEXIST (File exists)
[pid  4534] getuid32()                  = 0
[pid  4534] getgid32()                  = 0
[pid  4534] stat64("/var/lib/avast4/400.vps", {st_mode=S_IFREG|0644, st_size=163012739, ...}) = 0
[pid  4534] stat64("/var/lib/avast4/400.vps", {st_mode=S_IFREG|0644, st_size=163012739, ...}) = 0
[pid  4534] shmget(0x6c260fa0, 0, 0)    = -1 ENOENT (No such file or directory)
[pid  4534] semctl(1933317, 0, IPC_STAT, 0xffd06618) = 0
[pid  4534] open("/var/lib/avast4/400.vps", O_RDONLY|O_LARGEFILE^C^Z

Jason Haar <jhaar>

 

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    Follow 3 latest changes.

    Date Changed by Updated Field Previous Value => Replaced by
    2016-04-15 _71007 Open/ClosedOpen Closed
    2015-03-11 _71007 StatusNone In Progress
        Assigned toNone _71007

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