Edit report at https://bugs.php.net/bug.php?id=35326&edit=1
ID: 35326
Comment by: gustavo dot straube at gmail dot com
Reported by: bugs dot php dot net at chsc dot dk
Summary: Concurrency issue with recursive mkdir
Status: Not a bug
Type: Feature/Change Request
Package: *General Issues
Operating System: Linux
PHP Version: 5.1.6
Block user comment: N
Private report: N
New Comment:
> We don't need a locking mechanism. If the creation of a directory fails, we
> just need to check if it exists anyway [...]
In the application I experienced this bug, I do have a condition before the
directory creation.
1. if (!is_dir($path))
2. mkdir($path, 0755, true);
If I have two concurrent process ("A" and "B") running the code in this order
(process - line):
A - 1
B - 1
B - 2
A - 2
When process "A" verified the directory existence, it really didn't exist.
Previous Comments:
------------------------------------------------------------------------
[2013-10-30 08:49:24] bugs dot php dot net at chsc dot dk
> To create the right locking mechanism to avoid such issue to happen
We don't need a locking mechanism. If the creation of a directory fails, we
just need to check if it exists anyway (i.e. it has been created by a
concurrent thread). If it does, we can proceed to create the subdirectories.
------------------------------------------------------------------------
[2013-10-01 04:52:05] paj...@php.net
Update the status.
And adding a small note about "why is it not a php bug", what is described here
can happen anywhere outside php as well, be a shell script, ftp/ssh, etc.
------------------------------------------------------------------------
[2013-10-01 04:21:25] paj...@php.net
Should have been:
... and will drastically affect performance without actually solving the
problem....
------------------------------------------------------------------------
[2013-10-01 04:15:57] paj...@php.net
I am not sure it is actually a PHP problem. To create the right locking
mechanism
to avoid such issue to happen between (almost) simultaneous requests is the
application developer job, not the core.
Adding such tests should be done in almost all file creation operations (and
some
other) and will drastically performance without actually solving the problem.
------------------------------------------------------------------------
[2013-09-30 10:39:45] me at vlastv dot ru
Problem still exists in PHP 5.4.1.
------------------------------------------------------------------------
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