From mboxrd@z Thu Jan 1 00:00:00 1970 From: Christoph Hellwig Subject: Re: [PATCH RFC 1/3] vfs: add copy_file_range syscall and vfs helper Date: Tue, 14 Apr 2015 12:23:25 -0700 Message-ID: <20150414192325.GB20599@infradead.org> References: <20150411000208.GA20949@lenny.home.zabbo.net> <20150411090402.67d22d02@tlielax.poochiereds.net> <20150414165344.GA21421@infradead.org> <552D4B5D.3090904@Netapp.com> <20150414181911.GA2080@fieldses.org> <20150414182241.GB23129@lenny.home.zabbo.net> <20150414182906.GB2080@fieldses.org> <20150414185408.GC23129@lenny.home.zabbo.net> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: "J. Bruce Fields" , Anna Schumaker , Christoph Hellwig , Jeff Layton , Trond Myklebust , Linux Kernel Mailing List , Linux FS-devel Mailing List , linux-btrfs-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Linux NFS Mailing List , linux-scsi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Zach Brown Return-path: Content-Disposition: inline In-Reply-To: <20150414185408.GC23129-fypN+1c5dIyjpB87vu3CluTW4wlIGRCZ@public.gmane.org> Sender: linux-nfs-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: linux-fsdevel.vger.kernel.org On Tue, Apr 14, 2015 at 11:54:08AM -0700, Zach Brown wrote: > Is this relying on btrfs range cloning being atomic? It certainly > doesn't look atomic. It can modify items across an arbitrarily large > number of leaf blocks. It can make the changes across multiple > transactions which could introduce partial modification on reboot after > crashes. It can fail (the dynamic duo: enomem, eio) and leave the > desintation partially modified. I didn't mean atomic in the failure atomic sense, but in the sense of being atomic vs other writes, similar to how Posix specifies it for writes vs other writes. Guess I need to express this intent better. -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html