From mboxrd@z Thu Jan 1 00:00:00 1970 From: Artur Paszkiewicz Subject: Re: [PATCH v2 09/12] raid5-ppl: read PPL signature from IMSM metadata Date: Wed, 7 Dec 2016 15:38:05 +0100 Message-ID: <0e661d59-033e-6797-b5d1-d30cdb04ef11@intel.com> References: <20161205153113.7268-1-artur.paszkiewicz@intel.com> <20161205153113.7268-10-artur.paszkiewicz@intel.com> <871sxk4jj0.fsf@notabene.neil.brown.name> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <871sxk4jj0.fsf@notabene.neil.brown.name> Sender: linux-raid-owner@vger.kernel.org To: NeilBrown , shli@kernel.org Cc: linux-raid@vger.kernel.org List-Id: linux-raid.ids On 12/07/2016 02:25 AM, NeilBrown wrote: > On Tue, Dec 06 2016, Artur Paszkiewicz wrote: > >> The PPL signature is used to determine if the stored PPL is valid for a >> given array. With IMSM, the PPL signature should match the >> orig_family_num field of the superblock. To avoid passing this value >> from userspace, it can be read from the IMSM MPB when initializing the >> log. > > It is up to mdadm to determine if the PPL is valid. It would only tell > the kernel that a PPL exists if it is valid... The kernel also has to know this value because it writes it to the PPL header. So yet another sysfs attribute just for this value? How about adding a directory similar to "bitmap" to hold all the PPL related settings? Artur