Messages in this thread | | | Subject | Re: [PATCH 17/18] [GFS2] Remove support for unused and pointless flag | From | Steven Whitehouse <> | Date | Fri, 11 Jul 2008 12:52:19 +0100 |
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Hi,
On Fri, 2008-07-11 at 07:19 -0400, linux-os (Dick Johnson) wrote: > On Fri, 11 Jul 2008 swhiteho@redhat.com wrote: > > > From: Steven Whitehouse <swhiteho@redhat.com> > > > > The ability to mark files for direct i/o access when opened > > normally is both unused and pointless, so this patch removes > > support for that feature. > [Snipped...] > > So linux is no longer going to support commercial databases? > Oracle and others need the O_DIRECT attribute. Linux can > probably igonore it, but such an open cannot fail or else > Linux gets thrown out of the commercial enterprise when > an upgrade disables an entire financial institution. > > Cheers, > Dick Johnson > Penguin : Linux version 2.6.22.1 on an i686 machine (5588.28 BogoMips). > My book : http://www.AbominableFirebug.com/ > _ > No, thats not what it means...., but perhaps I could have explained it better. You can still use O_DIRECT flags in open syscalls in exactly the same way as before. What this patch removes is the (never used, and IMHO pointless) feature of being able to set a flag on the inode (via chattr/setattr) to force open's to set O_DIRECT in every case, even when the application didn't ask for it. The reason that its pointless is that applications which don't otherwise support O_DIRECT are very unlikely to supply suitably aligned buffers and I/O requests, so that overriding the O_DIRECT flag for such applications will most likely result in an I/O error.
GFS2 will still support O_DIRECT just the same as it has always done, and this doesn't affect any other filesystem's support for that feature either,
Steve.
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