> -----Original Message----- > From: linux-btrfs-ow...@vger.kernel.org [mailto:linux-btrfs- > ow...@vger.kernel.org] On Behalf Of Qu Wenruo > Sent: Monday, 14 August 2017 4:37 PM > To: Christoph Hellwig <h...@infradead.org>; Christoph Anton Mitterer > <cales...@scientia.net> > Cc: Btrfs BTRFS <linux-btrfs@vger.kernel.org> > Subject: Re: RedHat 7.4 Release Notes: "Btrfs has been deprecated" - wut? > > > > On 2017年08月12日 15:42, Christoph Hellwig wrote: > > On Sat, Aug 12, 2017 at 02:10:18AM +0200, Christoph Anton Mitterer wrote: > >> Qu Wenruo wrote: > >>> Although Btrfs can disable data CoW, nodatacow also disables data > >>> checksum, which is another main feature for btrfs. > >> > >> Then decoupling of the two should probably decoupled and support for > >> notdatacow+checksumming be implemented?! > > > > And how are you going to write your data and checksum atomically when > > doing in-place updates? > > Exactly, that's the main reason I can figure out why btrfs disables checksum > for nodatacow.
But does it matter if it's not strictly atomic? By turning off COW it implies you accept the risk of an ill-timed failure. Although from my point of view any reason that would require COW to be disabled implies you're using the wrong filesystem anyway. Paul.
