From mboxrd@z Thu Jan 1 00:00:00 1970 From: Christoph Hellwig Subject: Re: [PATCH 2/6] Show device as journal in --detail --examine Date: Tue, 1 Sep 2015 23:53:03 -0700 Message-ID: <20150902065303.GA20708@infradead.org> References: <1440804426-1461372-1-git-send-email-songliubraving@fb.com> <1440804426-1461372-3-git-send-email-songliubraving@fb.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <1440804426-1461372-3-git-send-email-songliubraving@fb.com> Sender: linux-raid-owner@vger.kernel.org To: Song Liu Cc: linux-raid@vger.kernel.org, shli@fb.com, dan.j.williams@intel.com, neilb@suse.de, hch@infradead.org List-Id: linux-raid.ids > #define MD_FEATURE_NEW_OFFSET 64 /* new_offset must be honoured */ > +#define MD_FEATURE_JOURNAL 512 /* support write journal */ The kernel patches are using 256 here, so your userspace won't work with them but rather generate very unhelpful warnings: [ 16.177710] md: sdc does not have a valid v1.2 superblock, not importing! [ 16.178634] md: md_import_device returned -22 mdadm: ADD_NEW_DISK for /dev/sdc failed: Invalid argument