Re: [RFC PATCH] fpathconf() for fsync() behavior

[Valerie Aurora Henson <vaurora@redhat.com>]

On Thu, Apr 23, 2009 at 07:11:47AM -0400, Christoph Hellwig wrote:
> On Wed, Apr 22, 2009 at 08:12:57PM -0400, Valerie Aurora Henson wrote:
> > In the default mode for ext3 and btrfs, fsync() is both slow and
> > unnecessary for some important application use cases - at the same
> > time that it is absolutely required for correctness for other modes of
> > ext3, ext4, XFS, etc.  If applications could easilyl distinguish
> > between the two cases, they would be more likely to be correct and
> > fast.
> > 
> > How about an fpathconf() variable, something like _PC_ORDERED?  E.g.:
> 
> Before we add any new fpathconf varibale we need a reall (f)pathconf(at)
> syscall so that the fs driver can exposed it's characteristics, having
> to replicate that information to glibc especially for something required
> for data integrity is a receipe for a desaster.

I think a real pathconf() is a great idea, regardless of the solution
for this exact problem.  Anyone want to beat me to the patch?  I
really need to be working on union mounts right now.

-VAL