From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jamie Lokier Subject: Re: [PATCH 1/3] fs: Document the reflink(2) system call. Date: Tue, 5 May 2009 23:03:30 +0100 Message-ID: <20090505220330.GB7574@shareable.org> References: <1241331303-23753-1-git-send-email-joel.becker@oracle.com> <1241331303-23753-2-git-send-email-joel.becker@oracle.com> <20090505010703.GA12731@shareable.org> <20090505071608.GB10258@mail.oracle.com> <20090505130114.GD17486@mit.edu> <20090505131907.GF25328@shareable.org> <1241530798.7244.65.camel@think.oraclecorp.com> <20090505153629.GB31100@shareable.org> <20090505164619.GA32180@logfs.org> <20090505165433.GB32180@logfs.org> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: Chris Mason , Theodore Tso , linux-fsdevel@vger.kernel.org, jmorris@namei.org, ocfs2-devel@oss.oracle.com, viro@zeniv.linux.org.uk To: =?iso-8859-1?Q?J=F6rn?= Engel Return-path: Received: from mail2.shareable.org ([80.68.89.115]:35191 "EHLO mail2.shareable.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752917AbZEEWDh (ORCPT ); Tue, 5 May 2009 18:03:37 -0400 Content-Disposition: inline In-Reply-To: <20090505165433.GB32180@logfs.org> Sender: linux-fsdevel-owner@vger.kernel.org List-ID: J=F6rn Engel wrote: > On Tue, 5 May 2009 18:46:19 +0200, J=F6rn Engel wrote: > > And depending on the fs design, the read/write loop can be > > replaced with finer-grained reference counting. >=20 > And maybe finer-grained reference counting should be a requirement fo= r > copyfile/cowlink/reflink or whatever we call it. With a large file o= n > slow media, open("foo", O_RDWR); should still return in a reasonable > amount of time. Not after ten minutes. Or 8 hours, which is how long it took me to copy a really large file last time... Oh, and are open() or write() on regular files interruptible per POSIX? Didn't think so :-) =46ortunately BTRFS does do fine-grained extent sharing, and reflink so it should work ok on BTRFS. -- Jamie -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel= " in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html