From: Christoph Hellwig <hch@infradead.org>
To: Anand Avati <avati@gluster.com>
Cc: miklos@szeredi.hu, fuse-devel@lists.sourceforge.net,
linux-fsdevel@vger.kernel.org, linux-nfs@vger.kernel.org
Subject: Re: [PATCH v2 2/2] fuse: permit O_DIRECT flag in open()
Date: Wed, 27 Jul 2011 17:05:14 -0400 [thread overview]
Message-ID: <20110727210514.GD9066@infradead.org> (raw)
In-Reply-To: <1311764179-20326-2-git-send-email-avati@gluster.com>
On Wed, Jul 27, 2011 at 03:56:19AM -0700, Anand Avati wrote:
> FUSE currently disallows O_DIRECT flag in open(). It is tricky dealing with
> setting/unsetting of O_DIRECT flag on an open file. There are applications
> (primarily VMs and databases) which open files with O_DIRECT flag. These
> applications do not work on FUSE due to this limitation.
>
> The approach with this patch is to permit opens with O_DIRECT, but instead
> disable setting/unsetting of the O_DIRECT flag no matter how the file was
> opened. This limitation is for more practical than disallowing O_DIRECT
> altogether.
But it's also entirely incorrect. Fix your userspace to have a proper
fallback if O_DIRECT opens fail. It's a feature only supported by a few
filesystems, and very few operating systems.
next prev parent reply other threads:[~2011-07-27 21:05 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-07-27 10:56 [PATCH v2 1/2] vfs: pass 'struct file *' as parameter to ->check_flags() methods Anand Avati
[not found] ` <1311764179-20326-1-git-send-email-avati-+FkPdpiNhgJBDgjK7y7TUQ@public.gmane.org>
2011-07-27 10:56 ` [PATCH v2 2/2] fuse: permit O_DIRECT flag in open() Anand Avati
2011-07-27 21:05 ` Christoph Hellwig [this message]
2011-07-28 8:14 ` Anand Avati
2011-07-28 11:49 ` Christoph Hellwig
2011-07-28 18:12 ` Anand Avati
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