From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1LaIRX-0003Qu-72 for qemu-devel@nongnu.org; Thu, 19 Feb 2009 18:36:35 -0500 Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43) id 1LaIRV-0003Qi-Mr for qemu-devel@nongnu.org; Thu, 19 Feb 2009 18:36:34 -0500 Received: from [199.232.76.173] (port=60261 helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1LaIRV-0003Qf-Jj for qemu-devel@nongnu.org; Thu, 19 Feb 2009 18:36:33 -0500 Received: from bsdimp.com ([199.45.160.85]:53749 helo=harmony.bsdimp.com) by monty-python.gnu.org with esmtps (TLS-1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.60) (envelope-from ) id 1LaIRV-0002rc-4X for qemu-devel@nongnu.org; Thu, 19 Feb 2009 18:36:33 -0500 Date: Thu, 19 Feb 2009 16:36:01 -0700 (MST) Message-Id: <20090219.163601.29203982.imp@bsdimp.com> Subject: Re: [Qemu-devel] migration: adding migration to/from a file (v2) From: "M. Warner Losh" In-Reply-To: <20090219202849.GE22319@shareable.org> References: <499DADBB.4080008@redhat.com> <499DBB8E.6030705@codemonkey.ws> <20090219202849.GE22319@shareable.org> Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Reply-To: qemu-devel@nongnu.org List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org, jamie@shareable.org Cc: uril@redhat.com In message: <20090219202849.GE22319@shareable.org> Jamie Lokier writes: : Anthony Liguori wrote: : > >Sure looks like a bug. : > I wish! It's Unix suckiness. : : Windows is the same. : It's a more of a conceptual problem than it looks, not merely an API bug. : : It comes down to "what would 'readable' and 'writable' mean on a file?". "Would a read or write operation block?" is a better way to look at the interface that select() or poll() provides. For a regular file, the answer is "no" since the writes are so fast and often asynchronous... Warner