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    Subjectadding proper O_SYNC/O_DSYNC, was Re: O_DIRECT and barriers
    On Thu, Aug 27, 2009 at 03:34:59PM +0100, Jamie Lokier wrote:
    > Christoph Hellwig wrote:
    > > Then again they already don't get what they expect and never did,
    > > so if we clear document and communicate the O_SYNC (that is Linux
    > > O_SYNC) requirement we might be able to go with this.
    > I'm thinking, while we're looking at this, that now is a really good
    > time to split up O_SYNC and O_DSYNC.
    > We have separate fsync and fdatasync, so it should be quite tidy now.
    > Then we can document using O_DSYNC on Linux, which is fine for older
    > versions because it has the same value as O_SYNC at the moment.

    Technically we could easily make O_SYNC really mean O_SYNC and implement
    a seaprate O_DSYNC at the kernel level.

    The question is how to handle this at the libc level. Currently glibc
    defines O_DSYNC to be O_SYNC. We would need to update glibc to pass
    through O_DSYNC for newer kernels and make sure it falls back to O_SYNC
    for olders. I'm not sure how feasible this is, but maybe Ulrich has
    some better ideas.

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      Last update: 2009-08-27 19:13    [W:0.019 / U:110.172 seconds]
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