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NFS file locking in PHP

Part of my last web application should write to the file as a sum as part of its logging. One of the problems that I noticed is that if there are several simultaneous users, the records can overwrite each other (instead of adding to the file). I assume this is because the destination file can be opened in several places at the same time.

flock(...) usually excellent, but it doesn’t work on NFS ... Which is a huge problem for me, since the production server uses an NFS array.

The closest thing I saw for the actual solution is trying to create a lock locator and wait until it is created. To say that this is a lack of elegance is an understatement of the year, perhaps a decade.

Any better ideas?

Edit: I have to add that I don’t have a root on the server, and it’s not always possible to do the repository in the near future, not least within my term.

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6 answers

Another dirty hack would be a flock()“local” file and only open / write to the NFS file if you hold the lock on the local file.

Edit: on page flock():

flock () will not work on NFS, and many other network file systems. Check your operating system documentation for more details.

Edit 2:

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NFSv2 NFSv3 (, " NFS" , ISBN 0-201-32570-5; - NFS ).

NFSv2 :

NFSv3 create .

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:

while ! ln -s . lock; do :; done

:

while ! ln -s ${f} ${f}.lock; do :; done

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mv lock deleteme && rm deleteme

:

mv ${f}.lock ${f}.deleteme && rm ${f}.deleteme

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symlink rename . : .

+14

Memcache, . ape flock() .

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// Check for lock, using $filename as key
$lock = $memcache->get($filename);

if(!$lock) {
    // Set lock in memcache for $filename
    $memcache->set($filename, 1);

    // Do file operations...

    // Blow away "lock"
    $memcache->delete($filename);
}

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+3

dio_fcntl() NFS. dio, php.

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flock() NFS, I/O , NFS . , .

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memcache .

if ($memcache->add($filename, 1, 1))
{
   $memcache->delete($filename);
}
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