From 90382ed9afeafd42ef193f0eadc6b2a252d6c24d Mon Sep 17 00:00:00 2001 From: Goldwyn Rodrigues Date: Wed, 24 Jun 2015 09:30:32 -0500 Subject: [PATCH] Fix read-balancing during node failure During a node failure, We need to suspend read balancing so that the reads are directed to the first device and stale data is not read. Suspending writes is not required because these would be recorded and synced eventually. A new flag MD_CLUSTER_SUSPEND_READ_BALANCING is set in recover_prep(). area_resyncing() will respond true for the entire devices if this flag is set and the request type is READ. The flag is cleared in recover_done(). Signed-off-by: Goldwyn Rodrigues Reported-By: David Teigland Signed-off-by: NeilBrown --- drivers/md/md-cluster.c | 12 +++++++++++- drivers/md/md-cluster.h | 2 +- drivers/md/raid1.c | 7 ++++--- 3 files changed, 16 insertions(+), 5 deletions(-) diff --git a/drivers/md/md-cluster.c b/drivers/md/md-cluster.c index fcfc4b9..0072190 100644 --- a/drivers/md/md-cluster.c +++ b/drivers/md/md-cluster.c @@ -44,6 +44,7 @@ struct resync_info { /* md_cluster_info flags */ #define MD_CLUSTER_WAITING_FOR_NEWDISK 1 +#define MD_CLUSTER_SUSPEND_READ_BALANCING 2 struct md_cluster_info { @@ -275,6 +276,9 @@ clear_bit: static void recover_prep(void *arg) { + struct mddev *mddev = arg; + struct md_cluster_info *cinfo = mddev->cluster_info; + set_bit(MD_CLUSTER_SUSPEND_READ_BALANCING, &cinfo->state); } static void recover_slot(void *arg, struct dlm_slot *slot) @@ -307,6 +311,7 @@ static void recover_done(void *arg, struct dlm_slot *slots, cinfo->slot_number = our_slot; complete(&cinfo->completion); + clear_bit(MD_CLUSTER_SUSPEND_READ_BALANCING, &cinfo->state); } static const struct dlm_lockspace_ops md_ls_ops = { @@ -816,12 +821,17 @@ static void resync_finish(struct mddev *mddev) resync_send(mddev, RESYNCING, 0, 0); } -static int area_resyncing(struct mddev *mddev, sector_t lo, sector_t hi) +static int area_resyncing(struct mddev *mddev, int direction, + sector_t lo, sector_t hi) { struct md_cluster_info *cinfo = mddev->cluster_info; int ret = 0; struct suspend_info *s; + if ((direction == READ) && + test_bit(MD_CLUSTER_SUSPEND_READ_BALANCING, &cinfo->state)) + return 1; + spin_lock_irq(&cinfo->suspend_lock); if (list_empty(&cinfo->suspend_list)) goto out; diff --git a/drivers/md/md-cluster.h b/drivers/md/md-cluster.h index 6817ee0..00defe2 100644 --- a/drivers/md/md-cluster.h +++ b/drivers/md/md-cluster.h @@ -18,7 +18,7 @@ struct md_cluster_operations { int (*metadata_update_start)(struct mddev *mddev); int (*metadata_update_finish)(struct mddev *mddev); int (*metadata_update_cancel)(struct mddev *mddev); - int (*area_resyncing)(struct mddev *mddev, sector_t lo, sector_t hi); + int (*area_resyncing)(struct mddev *mddev, int direction, sector_t lo, sector_t hi); int (*add_new_disk_start)(struct mddev *mddev, struct md_rdev *rdev); int (*add_new_disk_finish)(struct mddev *mddev); int (*new_disk_ack)(struct mddev *mddev, bool ack); diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c index 50cf0c8..94f5b55 100644 --- a/drivers/md/raid1.c +++ b/drivers/md/raid1.c @@ -541,7 +541,7 @@ static int read_balance(struct r1conf *conf, struct r1bio *r1_bio, int *max_sect if ((conf->mddev->recovery_cp < this_sector + sectors) || (mddev_is_clustered(conf->mddev) && - md_cluster_ops->area_resyncing(conf->mddev, this_sector, + md_cluster_ops->area_resyncing(conf->mddev, READ, this_sector, this_sector + sectors))) choose_first = 1; else @@ -1111,7 +1111,8 @@ static void make_request(struct mddev *mddev, struct bio * bio) ((bio_end_sector(bio) > mddev->suspend_lo && bio->bi_iter.bi_sector < mddev->suspend_hi) || (mddev_is_clustered(mddev) && - md_cluster_ops->area_resyncing(mddev, bio->bi_iter.bi_sector, bio_end_sector(bio))))) { + md_cluster_ops->area_resyncing(mddev, WRITE, + bio->bi_iter.bi_sector, bio_end_sector(bio))))) { /* As the suspend_* range is controlled by * userspace, we want an interruptible * wait. @@ -1124,7 +1125,7 @@ static void make_request(struct mddev *mddev, struct bio * bio) if (bio_end_sector(bio) <= mddev->suspend_lo || bio->bi_iter.bi_sector >= mddev->suspend_hi || (mddev_is_clustered(mddev) && - !md_cluster_ops->area_resyncing(mddev, + !md_cluster_ops->area_resyncing(mddev, WRITE, bio->bi_iter.bi_sector, bio_end_sector(bio)))) break; schedule(); -- 2.7.4