Ext3 users - Feb 2006 - Linux performance bug: fsync() for files with zero links

Linux kernel (as of 2.6.15.4) has the following performance bug:

Syncing (fsync() or fdatasync()) files with zero links (deleted files) in not
no-op, as it should be.

See details, a test C program, and the rationale in the URL below:

http://b2e.ex-code.com/index.php/soft/2006/02/24/linux_performance_bug_zero_links_fsync

In the article with the URL above it is also explained how to make much more
efficient /tmp directory when this bug will be fixed.

Somebody please make a patch.

-- 
Victor Porton (porton at ex-code.com) - http://porton.ex-code.com

On Feb 25, 2006  05:32 +0500, Victor Porton wrote:
> Linux kernel (as of 2.6.15.4) has the following performance bug:
> 
> Syncing (fsync() or fdatasync()) files with zero links (deleted files) in
not
> no-op, as it should be.
> 
> See details, a test C program, and the rationale in the URL below:
> 
>
http://b2e.ex-code.com/index.php/soft/2006/02/24/linux_performance_bug_zero_links_fsync
> 
> In the article with the URL above it is also explained how to make much
more
> efficient /tmp directory when this bug will be fixed.
> 
> Somebody please make a patch.
Of course, for a cluster filesystem it does make sense that fsync flushes
the data to disk even if the file has no links, because there may be other
clients that are accessing the same file...

Cheers, Andreas
--
Andreas Dilger
Principal Software Engineer
Cluster File Systems, Inc.