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: Feedback Type: Bug Package: Scripting Engine problem Operating System: Irrelevant PHP Version: 5.3.3 Block user comment: N New Comment: 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. Previous Comments: ------------------------------------------------------------------------ [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 ------------------------------------------------------------------------ [2010-10-16 02:05:13] cataphr...@php.net I can't reproduce this. I get the output "bar". File locks are released when the file are closed. Additionally, your 'actual result' section shows an unlock: ... write(3, "bar", 3) = 3 flock(3, LOCK_UN) = 0 <<<<<--- Am I missing something? ------------------------------------------------------------------------ [2010-10-15 17:16:19] admin at saltwaterc dot net Test script: --------------- <?php file_put_contents('foo', 'bar', LOCK_EX); $fh = fopen('foo', 'rb'); // there, I messed up the first time flock($fh, LOCK_SH); $file_contents = stream_get_contents($fh); flock($fh, LOCK_UN); fclose($fh); echo $file_contents.PHP_EOL; ------------------------------------------------------------------------ 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
