From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jes.Sorensen@redhat.com Subject: [PATCH] Revert "md: When RAID5 is dirty, force reconstruct-write instead of read-modify-write." Date: Tue, 17 Feb 2015 19:14:04 -0500 Message-ID: <1424218444-4022-1-git-send-email-Jes.Sorensen@redhat.com> Return-path: Sender: linux-raid-owner@vger.kernel.org To: neilb@suse.de Cc: linux-raid@vger.kernel.org, Jes Sorensen List-Id: linux-raid.ids From: Jes Sorensen This reverts commit a7854487cd7128a30a7f4f5259de9f67d5efb95f. The above patch would cause lockups of RAID4/5 arrays if a drive is going faulty during reconstruction. Signed-off-by: Jes Sorensen --- drivers/md/raid5.c | 19 +++---------------- 1 file changed, 3 insertions(+), 16 deletions(-) diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c index aa76865..bc3a085 100644 --- a/drivers/md/raid5.c +++ b/drivers/md/raid5.c @@ -3159,25 +3159,12 @@ static void handle_stripe_dirtying(struct r5conf *conf, int disks) { int rmw = 0, rcw = 0, i; - sector_t recovery_cp = conf->mddev->recovery_cp; - - /* RAID6 requires 'rcw' in current implementation. - * Otherwise, check whether resync is now happening or should start. - * If yes, then the array is dirty (after unclean shutdown or - * initial creation), so parity in some stripes might be inconsistent. - * In this case, we need to always do reconstruct-write, to ensure - * that in case of drive failure or read-error correction, we - * generate correct data from the parity. - */ - if (conf->max_degraded == 2 || - (recovery_cp < MaxSector && sh->sector >= recovery_cp)) { - /* Calculate the real rcw later - for now make it + if (conf->max_degraded == 2) { + /* RAID6 requires 'rcw' in current implementation + * Calculate the real rcw later - for now fake it * look like rcw is cheaper */ rcw = 1; rmw = 2; - pr_debug("force RCW max_degraded=%u, recovery_cp=%llu sh->sector=%llu\n", - conf->max_degraded, (unsigned long long)recovery_cp, - (unsigned long long)sh->sector); } else for (i = disks; i--; ) { /* would I have to read this buffer for read_modify_write */ struct r5dev *dev = &sh->dev[i]; -- 1.8.3.1