From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jonathan Brassow Subject: [PATCH] DM RAID: Fix for ineffective "sync" directive Date: Thu, 23 Aug 2012 10:31:54 -0500 Message-ID: <1345735914.25206.8.camel@f16> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Return-path: Sender: linux-raid-owner@vger.kernel.org To: linux-raid@vger.kernel.org Cc: neilb@suse.de, jbrassow@redhat.com List-Id: linux-raid.ids Neil, There are two ways I see to fix the problem of the "sync" table argument not causing the array to re-sync. We could set mddev->events to UINT_MAX and force an mddev/bitmap event mismatch - causing the bitmap code to set BITMAP_STALE itself. Otherwise, we can do as I have below and set BITMAP_STALE ourselves. The real difference is whether this is done before or after md_run(). The first solution can be done before md_run(); the second cannot because the bitmap is allocated during md_run(). Either solution works and correctly sets the bitmap to stale before bitmap_load() is called. So, rather than having to think about issues that come with setting events to UINT_MAX, I chose to set the bitmap stale after md_run(). brassow DM RAID: Fix for "sync" directive ineffectiveness There are two table arguments that can be given to a DM RAID target that control whether the array is forced to (re)synchronize or skip initialization: "sync" and "nosync". When "sync" is given, we set mddev->recovery_cp to 0 in order to cause the device to resynchronize. This is insufficient if there is a bitmap in use, because the array will simply look at the bitmap and see that there is no recovery necessary. Once md_run() is called and creates the bitmap, we set the bitmap as stale. When the bitmap is loaded during the resume phase, a full resync will result. Signed-off-by: Jonathan Brassow Index: linux-upstream/drivers/md/dm-raid.c =================================================================== --- linux-upstream.orig/drivers/md/dm-raid.c +++ linux-upstream/drivers/md/dm-raid.c @@ -1123,6 +1123,10 @@ static int raid_ctr(struct dm_target *ti ret = -EINVAL; goto size_mismatch; } + + if (rs->print_flags & DMPF_SYNC) + set_bit(BITMAP_STALE, &(rs->md.bitmap->flags)); + rs->callbacks.congested_fn = raid_is_congested; dm_table_add_target_callbacks(ti->table, &rs->callbacks);