Edit report at http://bugs.php.net/bug.php?id=53076&edit=1
ID: 53076 Comment by: admin at saltwaterc dot net Reported by: admin at saltwaterc dot net Summary: file_put_contents doesn't release the LOCK_EX Status: Bogus Type: Bug Package: Scripting Engine problem Operating System: Irrelevant PHP Version: 5.3.3 Block user comment: N Private report: N New Comment: Bogus? Seriously? That's a three line patch. A simple if. Now look, I am not a wannabe researcher trying to find theoretical problems with your scripting engine. I'm an actual system administrator, doing actual live PHP deployments and that condition actually broke our application (specifically an IPB product, forum + support module) with our actual network filesystem. Real life situation, not Hollywood junk. I may not have your operating system, specifically *nix, experience, but I can recognize an issue when it is present. I already told you that not having that explicit unlock may cause deadlocks, depending onto the *filesystem implementation*. I know, it's a very specific situation, would (mostly?) happen on buggy (network?) filesystems, but this attitude: "it's their junk, let them fix it" won't help anybody when in production scenarios the applications start to crash. I know that probably this would be ignored, and sometimes ignorance is bliss, but ignorance doesn't fix software. Just don't tell me that I am the one that doesn't understand the situation since you keep quoting: "closing the file will both release the locks and flush the data to disk" - this is simply not universally true. I rest my case, do whatever you want. Previous Comments: ------------------------------------------------------------------------ [2010-11-25 20:39:47] il...@php.net Sorry, but your problem does not imply a bug in PHP itself. For a list of more appropriate places to ask for help using PHP, please visit http://www.php.net/support.php as this bug system is not the appropriate forum for asking support questions. Due to the volume of reports we can not explain in detail here why your report is not a bug. The support channels will be able to provide an explanation for you. Thank you for your interest in PHP. Closing the file will both release the locks and flush the data to disk. If you have an interrupt happen it between, the same could be true before flush or unlock. ------------------------------------------------------------------------ [2010-10-16 14:56:31] admin at saltwaterc dot net My bad. I did the bug report in a little bit hurry. The 'actual result' is broken since I use my patch for my PHP build, while keeping an eye on my old strace outputs, with actual production setup: Invision Power Board + Minify + PHP 5.3.3 (PHP-FPM) + Ubuntu Server 10.04. Therefore, it's kinda 'emulated'. But it does happen with the standard PHP of doing things. However, the lock release when the stream is closed depends onto the filesystem implementation. See this changelog: http://ftp.zresearch.com/pub/gluster/glusterfs/3.0/3.0.3/GlusterFS_3.0.3_Release _Notes.pdf I know that usually this happens on buggy filesystems that have issues with advisory locking, but in my humble opinion this doesn't mean that the file_put_contents should not include those 3 lines of code that make things to be a little bit stable from now on such as avoiding deadlocks when things go unplanned. As I said, this specific conditions took down one of our production virtual hosts. ------------------------------------------------------------------------ [2010-10-16 09:52:46] cataphr...@php.net I don't get an explicit LOCK_UN either, but it should be unnecessary, as locks are released when the file is closed. @crrodriguez There's no need to call php_stream_flush as that is already done when the stream is closed. See: http://lxr.php.net/xref/PHP_TRUNK/main/streams/streams.c#_php_stream_free ------------------------------------------------------------------------ [2010-10-16 02:20:24] crrodriguez at opensuse dot org Patch ACK'ed , looks correct. BUT, you should also call php_stream_flush before closing the stream.. to make it slightly more reliable though there is still no warranty that the file is stored on the filesystem... article worth reading http://thunk.org/tytso/blog/2009/03/12/delayed-allocation- and-the-zero-length-file-problem/ ;) ------------------------------------------------------------------------ [2010-10-16 02:12:58] ras...@php.net Note the example code does an explicit unlock. Are you sure that isn't what you are seeing there? If you try: strace php -r 'file_put_contents('foo', 'bar', LOCK_EX);' Do you see an unlock still? I get: open("/home/rasmus/foo", O_WRONLY|O_CREAT, 0666) = 3 fstat(3, {st_mode=S_IFREG|0644, st_size=0, ...}) = 0 lseek(3, 0, SEEK_CUR) = 0 flock(3, LOCK_EX) = 0 ftruncate(3, 0) = 0 write(3, "bar", 3) = 3 close(3) = 0 ------------------------------------------------------------------------ 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 http://bugs.php.net/bug.php?id=53076 -- Edit this bug report at http://bugs.php.net/bug.php?id=53076&edit=1
