From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jamie Lokier Subject: Re: O_NONBLOCK for regular files Date: Thu, 18 Mar 2004 12:05:49 +0000 Sender: linux-fsdevel-owner@vger.kernel.org Message-ID: <20040318120549.GC29382@mail.shareable.org> References: <20040318083628.A25565@infradead.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: linux-fsdevel@vger.kernel.org Return-path: Received: from mail.shareable.org ([81.29.64.88]:8590 "EHLO mail.shareable.org") by vger.kernel.org with ESMTP id S262566AbUCRMGT (ORCPT ); Thu, 18 Mar 2004 07:06:19 -0500 To: Christoph Hellwig Content-Disposition: inline In-Reply-To: <20040318083628.A25565@infradead.org> List-Id: linux-fsdevel.vger.kernel.org Christoph Hellwig wrote: > It's used to to allow the HSM support code in XFS (not in the > kernel.org code due to the horrible design, just in the oss.sgi.com > tree) to return EAGAIN to the nfs server so it doesn't block all > nfsd threads on possible long-enduring HSM operations. How does nfsd get notified when the operation is possible? Does poll() work? If poll works that implies a system call returning EAGAIN triggers at least some part of the HSM operation (whichever part is slow) in the background -- in which case, isn't the existing AIO interface more appropriate? -- Jamie