lkml.org 
[lkml]   [2013]   [Mar]   [11]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    From
    SubjectRe: New copyfile system call - discuss before LSF?
    On Mon, Feb 25, 2013 at 04:03:01PM -0800, Zach Brown wrote:
    > > > I think it would be neat if it couldn't
    > > > corrupt data.
    > >
    > > It would also be neat if the moon were made of cheese...
    >
    > And there we have the lsf2013 t-shirt slogan. I think we're done here!
    >
    > - z

    Hey Everyone,
    So, of course, this thread happened while I was celebrating my
    10-year anniversary on a warm, sunny island. I won't trade. But let me
    drop my $0.02 in here.
    First, we have our T-shirt slogan. That overrides every other
    concern.
    Second, I agree that moving forward on anything is better than
    not. I haven't delivered the updated fastcopy(2) patch I promised two
    years ago, and I have to admit that I can't promise code on any sane
    timeframe.
    Back when I was working on this, I thought that link(2) was a
    good model for a full-file copy. Thus I came up with reflink(2). This
    eventually became the fastcopyu(2) proposal discussed two years ago. I
    did not think, and I still don't think, that we should conflate the API
    for "copy/clone this file in some way" (ala fastcopy(2)) with
    "duplicate/link this range of bytes" (ala BTRFS_IOC_CLONE_RANGE). I
    thought that splice(2) or something like it was a better fit for ranges;
    this thread has already had the same thought.
    fastcopy(2) had a provision for CoW for atomicity, including
    metadata. This is because ocfs2 reflinks *can* provide atomic clones
    with metadata included. I would like any new proposal to allow for
    that. If it does not, of course, callers can continue to use
    OCFS2_IOC_REFLINK, but I'd rather make it part of the generic behavior,
    so that generic tools come with it.

    Joel

    --

    "You don't make the poor richer by making the rich poorer."
    - Sir Winston Churchill

    http://www.jlbec.org/
    jlbec@evilplan.org


    \
     
     \ /
      Last update: 2013-03-11 11:21    [W:4.086 / U:0.060 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site