From d7bd398e97f236a2353689eca5e8950f67cd34d5 Mon Sep 17 00:00:00 2001 From: Song Liu Date: Wed, 23 Nov 2016 22:50:39 -0800 Subject: md/r5cache: handle alloc_page failure RMW of r5c write back cache uses an extra page to store old data for prexor. handle_stripe_dirtying() allocates this page by calling alloc_page(). However, alloc_page() may fail. To handle alloc_page() failures, this patch adds an extra page to disk_info. When alloc_page fails, handle_stripe() trys to use these pages. When these pages are used by other stripe (R5C_EXTRA_PAGE_IN_USE), the stripe is added to delayed_list. Signed-off-by: Song Liu Reviewed-by: NeilBrown Signed-off-by: Shaohua Li --- drivers/md/raid5-cache.c | 27 ++++++++++++++++- drivers/md/raid5.c | 78 ++++++++++++++++++++++++++++++++++++++++-------- drivers/md/raid5.h | 6 ++++ 3 files changed, 98 insertions(+), 13 deletions(-) diff --git a/drivers/md/raid5-cache.c b/drivers/md/raid5-cache.c index 5f817bdaceb9..5d3d238921e8 100644 --- a/drivers/md/raid5-cache.c +++ b/drivers/md/raid5-cache.c @@ -2326,15 +2326,40 @@ int r5c_try_caching_write(struct r5conf *conf, */ void r5c_release_extra_page(struct stripe_head *sh) { + struct r5conf *conf = sh->raid_conf; int i; + bool using_disk_info_extra_page; + + using_disk_info_extra_page = + sh->dev[0].orig_page == conf->disks[0].extra_page; for (i = sh->disks; i--; ) if (sh->dev[i].page != sh->dev[i].orig_page) { struct page *p = sh->dev[i].orig_page; sh->dev[i].orig_page = sh->dev[i].page; - put_page(p); + if (!using_disk_info_extra_page) + put_page(p); } + + if (using_disk_info_extra_page) { + clear_bit(R5C_EXTRA_PAGE_IN_USE, &conf->cache_state); + md_wakeup_thread(conf->mddev->thread); + } +} + +void r5c_use_extra_page(struct stripe_head *sh) +{ + struct r5conf *conf = sh->raid_conf; + int i; + struct r5dev *dev; + + for (i = sh->disks; i--; ) { + dev = &sh->dev[i]; + if (dev->orig_page != dev->page) + put_page(dev->orig_page); + dev->orig_page = conf->disks[i].extra_page; + } } /* diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c index dbab8c7eccb0..db909b9e37df 100644 --- a/drivers/md/raid5.c +++ b/drivers/md/raid5.c @@ -876,6 +876,8 @@ static void ops_run_io(struct stripe_head *sh, struct stripe_head_state *s) if (!test_bit(STRIPE_R5C_CACHING, &sh->state)) { /* writing out phase */ + if (s->waiting_extra_page) + return; if (r5l_write_stripe(conf->log, sh) == 0) return; } else { /* caching phase */ @@ -2007,6 +2009,7 @@ static struct stripe_head *alloc_stripe(struct kmem_cache *sc, gfp_t gfp, INIT_LIST_HEAD(&sh->batch_list); INIT_LIST_HEAD(&sh->lru); INIT_LIST_HEAD(&sh->r5c); + INIT_LIST_HEAD(&sh->log_list); atomic_set(&sh->count, 1); sh->log_start = MaxSector; for (i = 0; i < disks; i++) { @@ -2253,10 +2256,24 @@ static int resize_stripes(struct r5conf *conf, int newsize) */ ndisks = kzalloc(newsize * sizeof(struct disk_info), GFP_NOIO); if (ndisks) { - for (i=0; iraid_disks; i++) + for (i = 0; i < conf->pool_size; i++) ndisks[i] = conf->disks[i]; - kfree(conf->disks); - conf->disks = ndisks; + + for (i = conf->pool_size; i < newsize; i++) { + ndisks[i].extra_page = alloc_page(GFP_NOIO); + if (!ndisks[i].extra_page) + err = -ENOMEM; + } + + if (err) { + for (i = conf->pool_size; i < newsize; i++) + if (ndisks[i].extra_page) + put_page(ndisks[i].extra_page); + kfree(ndisks); + } else { + kfree(conf->disks); + conf->disks = ndisks; + } } else err = -ENOMEM; @@ -3580,10 +3597,10 @@ unhash: break_stripe_batch_list(head_sh, STRIPE_EXPAND_SYNC_FLAGS); } -static void handle_stripe_dirtying(struct r5conf *conf, - struct stripe_head *sh, - struct stripe_head_state *s, - int disks) +static int handle_stripe_dirtying(struct r5conf *conf, + struct stripe_head *sh, + struct stripe_head_state *s, + int disks) { int rmw = 0, rcw = 0, i; sector_t recovery_cp = conf->mddev->recovery_cp; @@ -3649,12 +3666,32 @@ static void handle_stripe_dirtying(struct r5conf *conf, dev->page == dev->orig_page && !test_bit(R5_LOCKED, &sh->dev[sh->pd_idx].flags)) { /* alloc page for prexor */ - dev->orig_page = alloc_page(GFP_NOIO); + struct page *p = alloc_page(GFP_NOIO); + + if (p) { + dev->orig_page = p; + continue; + } - /* will handle failure in a later patch*/ - BUG_ON(!dev->orig_page); + /* + * alloc_page() failed, try use + * disk_info->extra_page + */ + if (!test_and_set_bit(R5C_EXTRA_PAGE_IN_USE, + &conf->cache_state)) { + r5c_use_extra_page(sh); + break; + } + + /* extra_page in use, add to delayed_list */ + set_bit(STRIPE_DELAYED, &sh->state); + s->waiting_extra_page = 1; + return -EAGAIN; } + } + for (i = disks; i--; ) { + struct r5dev *dev = &sh->dev[i]; if ((dev->towrite || i == sh->pd_idx || i == sh->qd_idx || test_bit(R5_InJournal, &dev->flags)) && @@ -3730,6 +3767,7 @@ static void handle_stripe_dirtying(struct r5conf *conf, (s->locked == 0 && (rcw == 0 || rmw == 0) && !test_bit(STRIPE_BIT_DELAY, &sh->state))) schedule_reconstruction(sh, s, rcw == 0, 0); + return 0; } static void handle_parity_checks5(struct r5conf *conf, struct stripe_head *sh, @@ -4545,8 +4583,12 @@ static void handle_stripe(struct stripe_head *sh) if (ret == -EAGAIN || /* stripe under reclaim: !caching && injournal */ (!test_bit(STRIPE_R5C_CACHING, &sh->state) && - s.injournal > 0)) - handle_stripe_dirtying(conf, sh, &s, disks); + s.injournal > 0)) { + ret = handle_stripe_dirtying(conf, sh, &s, + disks); + if (ret == -EAGAIN) + goto finish; + } } } @@ -6458,6 +6500,8 @@ static void raid5_free_percpu(struct r5conf *conf) static void free_conf(struct r5conf *conf) { + int i; + if (conf->log) r5l_exit_log(conf->log); if (conf->shrinker.nr_deferred) @@ -6466,6 +6510,9 @@ static void free_conf(struct r5conf *conf) free_thread_groups(conf); shrink_stripes(conf); raid5_free_percpu(conf); + for (i = 0; i < conf->pool_size; i++) + if (conf->disks[i].extra_page) + put_page(conf->disks[i].extra_page); kfree(conf->disks); kfree(conf->stripe_hashtbl); kfree(conf); @@ -6612,9 +6659,16 @@ static struct r5conf *setup_conf(struct mddev *mddev) conf->disks = kzalloc(max_disks * sizeof(struct disk_info), GFP_KERNEL); + if (!conf->disks) goto abort; + for (i = 0; i < max_disks; i++) { + conf->disks[i].extra_page = alloc_page(GFP_KERNEL); + if (!conf->disks[i].extra_page) + goto abort; + } + conf->mddev = mddev; if ((conf->stripe_hashtbl = kzalloc(PAGE_SIZE, GFP_KERNEL)) == NULL) diff --git a/drivers/md/raid5.h b/drivers/md/raid5.h index d13fe45d6960..ed8e1362ab36 100644 --- a/drivers/md/raid5.h +++ b/drivers/md/raid5.h @@ -276,6 +276,7 @@ struct stripe_head_state { struct md_rdev *blocked_rdev; int handle_bad_blocks; int log_failed; + int waiting_extra_page; }; /* Flags for struct r5dev.flags */ @@ -439,6 +440,7 @@ enum { struct disk_info { struct md_rdev *rdev, *replacement; + struct page *extra_page; /* extra page to use in prexor */ }; /* @@ -559,6 +561,9 @@ enum r5_cache_state { * only process stripes that are already * occupying the log */ + R5C_EXTRA_PAGE_IN_USE, /* a stripe is using disk_info.extra_page + * for prexor + */ }; struct r5conf { @@ -765,6 +770,7 @@ extern void r5c_finish_stripe_write_out(struct r5conf *conf, struct stripe_head *sh, struct stripe_head_state *s); extern void r5c_release_extra_page(struct stripe_head *sh); +extern void r5c_use_extra_page(struct stripe_head *sh); extern void r5l_wake_reclaim(struct r5l_log *log, sector_t space); extern void r5c_handle_cached_data_endio(struct r5conf *conf, struct stripe_head *sh, int disks, struct bio_list *return_bi); -- cgit v1.2.3