Re: [RFC][PATCH 0/2] glibc: header file and manual updates for file-private locks

[Mike Frysinger <vapier at gentoo dot org>]

On Tuesday, February 11, 2014 14:03:54 Jeff Layton wrote:
> I've been working on a set of patches to add a new type file record lock
> to the Linux kernel that have less troublesome semantics on close and
> that are usable by threaded applications.
> 
> I have a blog post here with more details:
> 
>    
> http://jtlayton.wordpress.com/2014/01/07/file-private-posix-locks-aka-un-po
> six-locks/
> 
> ...and the latest kernel patchset is here:
> 
>     https://lkml.org/lkml/2014/1/14/554
> 
> This patchset represents a set of corresponding updates for glibc. It
> just adds the new cmd values to fcntl.h, and a manual update that
> discusses how to use the new locks.
> 
> I'm currently shooting for a merge in v3.15 kernel so I'm posting this
> as an RFC for now.

disclaimer: haven't read the kernel patches.  just the patch summary and your 
blog post.

looks like the new API manipulates the existing POSIX lock only -- flock based 
locks are still parallel.  too crazy to have the new API grab both since 
you're bringing proper semantics that cover both ?

a good summary of Linux locking from the perspective of userspace was posted 
here sometime ago:
	http://0pointer.de/blog/projects/locking.html
random notes/limitations/bugs are also in the various man pages like fcntl(2)

would be nice if we could cover as many known limitations as possible with the 
new api so as to not need yet another in the future ;)
-mike

Attachment: signature.asc
Description: This is a digitally signed message part.