Req #35326 [Com]: Concurrency issue with recursive mkdir

Edit report at https://bugs.php.net/bug.php?id=35326&edit=1 ID: 35326 Comment by: toonitw 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: Fixed in 8.1 https://github.com/php/php-src/pull/7383 Previous Comments: ------------------------------------------------------------------------ [2018-08-21 19:23:57] nasretdinov at gmail dot com You do not need any locking at all. mkdir() returns EEXIST when directory exists and it should not be treated as error in this function. "mkdir -p" does this, for example. ------------------------------------------------------------------------ [2013-10-30 10:13:35] gustavo dot straube at gmail dot com > 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. ------------------------------------------------------------------------ [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] pajoye@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] pajoye@php.net Should have been: ... and will drastically affect performance without actually solving the problem.... ------------------------------------------------------------------------ The remainder of the comments for this report are too long. To view the rest of the comments, please view the bug report online at https://bugs.php.net/bug.php?id=35326 -- Edit this bug report at https://bugs.php.net/bug.php?id=35326&edit=1