Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751765Ab2JYVUY (ORCPT ); Thu, 25 Oct 2012 17:20:24 -0400 Received: from mail-oa0-f46.google.com ([209.85.219.46]:65424 "EHLO mail-oa0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751553Ab2JYVUU (ORCPT ); Thu, 25 Oct 2012 17:20:20 -0400 MIME-Version: 1.0 In-Reply-To: References: From: Mike Waychison Date: Thu, 25 Oct 2012 14:19:59 -0700 Message-ID: Subject: Re: [PATCH v2 3/5] efi_pstore: Remove a logic erasing entries from a write callback to hold multiple logs To: Seiji Aguchi Cc: "linux-kernel@vger.kernel.org" , "linux-efi@vger.kernel.org" , "linux-acpi@vger.kernel.org" , "Luck, Tony (tony.luck@intel.com)" , "Matthew Garrett (mjg@redhat.com)" , "dzickus@redhat.com" , "dle-develop@lists.sourceforge.net" , Satoru Moriya Content-Type: text/plain; charset=ISO-8859-1 X-System-Of-Record: true Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2040 Lines: 42 On Thu, Oct 25, 2012 at 1:51 PM, Seiji Aguchi wrote: >> So doesn't this break erasing of existing dumps in pstore-efivars? >> Unless efi_pstore_read still understands the older variable name formats, users will be stranded with dumps consuming space in >> efivars that aren't exported via pstore anymore. > > Patch 2/5, 3/5 and 4/5 don't change an existing format of a variable name and don't break anything. > The existing format consists of type, id and ctime. And it is not moditied by these patches. > Here is a variable name (and guid) of efi_pstore in curret linus-tree. > > ls /sys/firmware/efi/vars/ > dump-type0-1-1351113059-cfc8fc79-be2e-4ddc-97f0-9f98bfe298a0 > dump-type0-2-1351113059-cfc8fc79-be2e-4ddc-97f0-9f98bfe298a0 > dump-type0-3-1351113059-cfc8fc79-be2e-4ddc-97f0-9f98bfe298a0 > > Variable Name: dump-type0-1-1351113059 > GUID: cfc8fc79-be2e-4ddc-97f0-9f98bfe298a0 Okay, this alleviates most of my concerns for ctime. > > On the other hand, patch 5/5 changes the format by adding sequence counter. > But efi_pstore_read is modied to work correctly in it. > > dump-type0-1-1-1351113059-cfc8fc79-be2e-4ddc-97f0-9f98bfe298a0 > > Variable Name: dump-type0-1-1-1351113059 > GUID: cfc8fc79-be2e-4ddc-97f0-9f98bfe298a0 > > If I need to elaborate more, please feel free to ask me:) > I'm not sure if I understand your question completely. In this case, I think efi_pstore_read in patch 5/5 should probably fall-back to trying to do a sscanf(...) == 3 if the sscanf(...) == 4 test fails so that dumps for older dumps from previous kernels are still visible to users, no? They can perhaps get a default count of 0? efi_pstore_erase would have to be updated to understand this as well. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/