/* * raid5.c : Multiple Devices driver for Linux * Copyright (C) 1996, 1997 Ingo Molnar, Miguel de Icaza, Gadi Oxman * Copyright (C) 1999, 2000 Ingo Molnar * Copyright (C) 2002, 2003 H. Peter Anvin * * RAID-4/5/6 management functions. * Thanks to Penguin Computing for making the RAID-6 development possible * by donating a test server! * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2, or (at your option) * any later version. * * You should have received a copy of the GNU General Public License * (for example /usr/src/linux/COPYING); if not, write to the Free * Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */ /* * BITMAP UNPLUGGING: * * The sequencing for updating the bitmap reliably is a little * subtle (and I got it wrong the first time) so it deserves some * explanation. * * We group bitmap updates into batches. Each batch has a number. * We may write out several batches at once, but that isn't very important. * conf->bm_write is the number of the last batch successfully written. * conf->bm_flush is the number of the last batch that was closed to * new additions. * When we discover that we will need to write to any block in a stripe * (in add_stripe_bio) we update the in-memory bitmap and record in sh->bm_seq * the number of the batch it will be in. This is bm_flush+1. * When we are ready to do a write, if that batch hasn't been written yet, * we plug the array and queue the stripe for later. * When an unplug happens, we increment bm_flush, thus closing the current * batch. * When we notice that bm_flush > bm_write, we write out all pending updates * to the bitmap, and advance bm_write to where bm_flush was. * This may occasionally write a bit out twice, but is sure never to * miss any bits. */ #include #include #include #include #include #include "md.h" #include "raid5.h" #include "bitmap.h" /* * Stripe cache */ #define NR_STRIPES 256 #define STRIPE_SIZE PAGE_SIZE #define STRIPE_SHIFT (PAGE_SHIFT - 9) #define STRIPE_SECTORS (STRIPE_SIZE>>9) #define IO_THRESHOLD 1 #define BYPASS_THRESHOLD 1 #define NR_HASH (PAGE_SIZE / sizeof(struct hlist_head)) #define HASH_MASK (NR_HASH - 1) #define stripe_hash(conf, sect) (&((conf)->stripe_hashtbl[((sect) >> STRIPE_SHIFT) & HASH_MASK])) /* bio's attached to a stripe+device for I/O are linked together in bi_sector * order without overlap. There may be several bio's per stripe+device, and * a bio could span several devices. * When walking this list for a particular stripe+device, we must never proceed * beyond a bio that extends past this device, as the next bio might no longer * be valid. * This macro is used to determine the 'next' bio in the list, given the sector * of the current stripe+device */ #define r5_next_bio(bio, sect) ( ( (bio)->bi_sector + ((bio)->bi_size>>9) < sect + STRIPE_SECTORS) ? (bio)->bi_next : NULL) /* * The following can be used to debug the driver */ #define RAID5_PARANOIA 1 #if RAID5_PARANOIA && defined(CONFIG_SMP) # define CHECK_DEVLOCK() assert_spin_locked(&conf->device_lock) #else # define CHECK_DEVLOCK() #endif #ifdef DEBUG #define inline #define __inline__ #endif #define printk_rl(args...) ((void) (printk_ratelimit() && printk(args))) /* * We maintain a biased count of active stripes in the bottom 16 bits of * bi_phys_segments, and a count of processed stripes in the upper 16 bits */ static inline int raid5_bi_phys_segments(struct bio *bio) { return bio->bi_phys_segments & 0xffff; } static inline int raid5_bi_hw_segments(struct bio *bio) { return (bio->bi_phys_segments >> 16) & 0xffff; } static inline int raid5_dec_bi_phys_segments(struct bio *bio) { --bio->bi_phys_segments; return raid5_bi_phys_segments(bio); } static inline int raid5_dec_bi_hw_segments(struct bio *bio) { unsigned short val = raid5_bi_hw_segments(bio); --val; bio->bi_phys_segments = (val << 16) | raid5_bi_phys_segments(bio); return val; } static inline void raid5_set_bi_hw_segments(struct bio *bio, unsigned int cnt) { bio->bi_phys_segments = raid5_bi_phys_segments(bio) || (cnt << 16); } /* Find first data disk in a raid6 stripe */ static inline int raid6_d0(struct stripe_head *sh) { if (sh->ddf_layout) /* ddf always start from first device */ return 0; /* md starts just after Q block */ if (sh->qd_idx == sh->disks - 1) return 0; else return sh->qd_idx + 1; } static inline int raid6_next_disk(int disk, int raid_disks) { disk++; return (disk < raid_disks) ? disk : 0; } /* When walking through the disks in a raid5, starting at raid6_d0, * We need to map each disk to a 'slot', where the data disks are slot * 0 .. raid_disks-3, the parity disk is raid_disks-2 and the Q disk * is raid_disks-1. This help does that mapping. */ static int raid6_idx_to_slot(int idx, struct stripe_head *sh, int *count, int syndrome_disks) { int slot; if (idx == sh->pd_idx) return syndrome_disks; if (idx == sh->qd_idx) return syndrome_disks + 1; slot = (*count)++; return slot; } static void return_io(struct bio *return_bi) { struct bio *bi = return_bi; while (bi) { return_bi = bi->bi_next; bi->bi_next = NULL; bi->bi_size = 0; bio_endio(bi, 0); bi = return_bi; } } static void print_raid5_conf (raid5_conf_t *conf); static int stripe_operations_active(struct stripe_head *sh) { return sh->check_state || sh->reconstruct_state || test_bit(STRIPE_BIOFILL_RUN, &sh->state) || test_bit(STRIPE_COMPUTE_RUN, &sh->state); } static void __release_stripe(raid5_conf_t *conf, struct stripe_head *sh) { if (atomic_dec_and_test(&sh->count)) { BUG_ON(!list_empty(&sh->lru)); BUG_ON(atomic_read(&conf->active_stripes)==0); if (test_bit(STRIPE_HANDLE, &sh->state)) { if (test_bit(STRIPE_DELAYED, &sh->state)) { list_add_tail(&sh->lru, &conf->delayed_list); blk_plug_device(conf->mddev->queue); } else if (test_bit(STRIPE_BIT_DELAY, &sh->state) && sh->bm_seq - conf->seq_write > 0) { list_add_tail(&sh->lru, &conf->bitmap_list); blk_plug_device(conf->mddev->queue); } else { clear_bit(STRIPE_BIT_DELAY, &sh->state); list_add_tail(&sh->lru, &conf->handle_list); } md_wakeup_thread(conf->mddev->thread); } else { BUG_ON(stripe_operations_active(sh)); if (test_and_clear_bit(STRIPE_PREREAD_ACTIVE, &sh->state)) { atomic_dec(&conf->preread_active_stripes); if (atomic_read(&conf->preread_active_stripes) < IO_THRESHOLD) md_wakeup_thread(conf->mddev->thread); } atomic_dec(&conf->active_stripes); if (!test_bit(STRIPE_EXPANDING, &sh->state)) { list_add_tail(&sh->lru, &conf->inactive_list); wake_up(&conf->wait_for_stripe); if (conf->retry_read_aligned) md_wakeup_thread(conf->mddev->thread); } } } } static void release_stripe(struct stripe_head *sh) { raid5_conf_t *conf = sh->raid_conf; unsigned long flags; spin_lock_irqsave(&conf->device_lock, flags); __release_stripe(conf, sh); spin_unlock_irqrestore(&conf->device_lock, flags); } static inline void remove_hash(struct stripe_head *sh) { pr_debug("remove_hash(), stripe %llu\n", (unsigned long long)sh->sector); hlist_del_init(&sh->hash); } static inline void insert_hash(raid5_conf_t *conf, struct stripe_head *sh) { struct hlist_head *hp = stripe_hash(conf, sh->sector); pr_debug("insert_hash(), stripe %llu\n", (unsigned long long)sh->sector); CHECK_DEVLOCK(); hlist_add_head(&sh->hash, hp); } /* find an idle stripe, make sure it is unhashed, and return it. */ static struct stripe_head *get_free_stripe(raid5_conf_t *conf) { struct stripe_head *sh = NULL; struct list_head *first; CHECK_DEVLOCK(); if (list_empty(&conf->inactive_list)) goto out; first = conf->inactive_list.next; sh = list_entry(first, struct stripe_head, lru); list_del_init(first); remove_hash(sh); atomic_inc(&conf->active_stripes); out: return sh; } static void shrink_buffers(struct stripe_head *sh, int num) { struct page *p; int i; for (i=0; idev[i].page; if (!p) continue; sh->dev[i].page = NULL; put_page(p); } } static int grow_buffers(struct stripe_head *sh, int num) { int i; for (i=0; idev[i].page = page; } return 0; } static void raid5_build_block(struct stripe_head *sh, int i, int previous); static void stripe_set_idx(sector_t stripe, raid5_conf_t *conf, int previous, struct stripe_head *sh); static void init_stripe(struct stripe_head *sh, sector_t sector, int previous) { raid5_conf_t *conf = sh->raid_conf; int i; BUG_ON(atomic_read(&sh->count) != 0); BUG_ON(test_bit(STRIPE_HANDLE, &sh->state)); BUG_ON(stripe_operations_active(sh)); CHECK_DEVLOCK(); pr_debug("init_stripe called, stripe %llu\n", (unsigned long long)sh->sector); remove_hash(sh); sh->generation = conf->generation - previous; sh->disks = previous ? conf->previous_raid_disks : conf->raid_disks; sh->sector = sector; stripe_set_idx(sector, conf, previous, sh); sh->state = 0; for (i = sh->disks; i--; ) { struct r5dev *dev = &sh->dev[i]; if (dev->toread || dev->read || dev->towrite || dev->written || test_bit(R5_LOCKED, &dev->flags)) { printk(KERN_ERR "sector=%llx i=%d %p %p %p %p %d\n", (unsigned long long)sh->sector, i, dev->toread, dev->read, dev->towrite, dev->written, test_bit(R5_LOCKED, &dev->flags)); BUG(); } dev->flags = 0; raid5_build_block(sh, i, previous); } insert_hash(conf, sh); } static struct stripe_head *__find_stripe(raid5_conf_t *conf, sector_t sector, short generation) { struct stripe_head *sh; struct hlist_node *hn; CHECK_DEVLOCK(); pr_debug("__find_stripe, sector %llu\n", (unsigned long long)sector); hlist_for_each_entry(sh, hn, stripe_hash(conf, sector), hash) if (sh->sector == sector && sh->generation == generation) return sh; pr_debug("__stripe %llu not in cache\n", (unsigned long long)sector); return NULL; } static void unplug_slaves(mddev_t *mddev); static void raid5_unplug_device(struct request_queue *q); static struct stripe_head * get_active_stripe(raid5_conf_t *conf, sector_t sector, int previous, int noblock) { struct stripe_head *sh; pr_debug("get_stripe, sector %llu\n", (unsigned long long)sector); spin_lock_irq(&conf->device_lock); do { wait_event_lock_irq(conf->wait_for_stripe, conf->quiesce == 0, conf->device_lock, /* nothing */); sh = __find_stripe(conf, sector, conf->generation - previous); if (!sh) { if (!conf->inactive_blocked) sh = get_free_stripe(conf); if (noblock && sh == NULL) break; if (!sh) { conf->inactive_blocked = 1; wait_event_lock_irq(conf->wait_for_stripe, !list_empty(&conf->inactive_list) && (atomic_read(&conf->active_stripes) < (conf->max_nr_stripes *3/4) || !conf->inactive_blocked), conf->device_lock, raid5_unplug_device(conf->mddev->queue) ); conf->inactive_blocked = 0; } else init_stripe(sh, sector, previous); } else { if (atomic_read(&sh->count)) { BUG_ON(!list_empty(&sh->lru) && !test_bit(STRIPE_EXPANDING, &sh->state)); } else { if (!test_bit(STRIPE_HANDLE, &sh->state)) atomic_inc(&conf->active_stripes); if (list_empty(&sh->lru) && !test_bit(STRIPE_EXPANDING, &sh->state)) BUG(); list_del_init(&sh->lru); } } } while (sh == NULL); if (sh) atomic_inc(&sh->count); spin_unlock_irq(&conf->device_lock); return sh; } static void raid5_end_read_request(struct bio *bi, int error); static void raid5_end_write_request(struct bio *bi, int error); static void ops_run_io(struct stripe_head *sh, struct stripe_head_state *s) { raid5_conf_t *conf = sh->raid_conf; int i, disks = sh->disks; might_sleep(); for (i = disks; i--; ) { int rw; struct bio *bi; mdk_rdev_t *rdev; if (test_and_clear_bit(R5_Wantwrite, &sh->dev[i].flags)) rw = WRITE; else if (test_and_clear_bit(R5_Wantread, &sh->dev[i].flags)) rw = READ; else continue; bi = &sh->dev[i].req; bi->bi_rw = rw; if (rw == WRITE) bi->bi_end_io = raid5_end_write_request; else bi->bi_end_io = raid5_end_read_request; rcu_read_lock(); rdev = rcu_dereference(conf->disks[i].rdev); if (rdev && test_bit(Faulty, &rdev->flags)) rdev = NULL; if (rdev) atomic_inc(&rdev->nr_pending); rcu_read_unlock(); if (rdev) { if (s->syncing || s->expanding || s->expanded) md_sync_acct(rdev->bdev, STRIPE_SECTORS); set_bit(STRIPE_IO_STARTED, &sh->state); bi->bi_bdev = rdev->bdev; pr_debug("%s: for %llu schedule op %ld on disc %d\n", __func__, (unsigned long long)sh->sector, bi->bi_rw, i); atomic_inc(&sh->count); bi->bi_sector = sh->sector + rdev->data_offset; bi->bi_flags = 1 << BIO_UPTODATE; bi->bi_vcnt = 1; bi->bi_max_vecs = 1; bi->bi_idx = 0; bi->bi_io_vec = &sh->dev[i].vec; bi->bi_io_vec[0].bv_len = STRIPE_SIZE; bi->bi_io_vec[0].bv_offset = 0; bi->bi_size = STRIPE_SIZE; bi->bi_next = NULL; if (rw == WRITE && test_bit(R5_ReWrite, &sh->dev[i].flags)) atomic_add(STRIPE_SECTORS, &rdev->corrected_errors); generic_make_request(bi); } else { if (rw == WRITE) set_bit(STRIPE_DEGRADED, &sh->state); pr_debug("skip op %ld on disc %d for sector %llu\n", bi->bi_rw, i, (unsigned long long)sh->sector); clear_bit(R5_LOCKED, &sh->dev[i].flags); set_bit(STRIPE_HANDLE, &sh->state); } } } static struct dma_async_tx_descriptor * async_copy_data(int frombio, struct bio *bio, struct page *page, sector_t sector, struct dma_async_tx_descriptor *tx) { struct bio_vec *bvl; struct page *bio_page; int i; int page_offset; if (bio->bi_sector >= sector) page_offset = (signed)(bio->bi_sector - sector) * 512; else page_offset = (signed)(sector - bio->bi_sector) * -512; bio_for_each_segment(bvl, bio, i) { int len = bio_iovec_idx(bio, i)->bv_len; int clen; int b_offset = 0; if (page_offset < 0) { b_offset = -page_offset; page_offset += b_offset; len -= b_offset; } if (len > 0 && page_offset + len > STRIPE_SIZE) clen = STRIPE_SIZE - page_offset; else clen = len; if (clen > 0) { b_offset += bio_iovec_idx(bio, i)->bv_offset; bio_page = bio_iovec_idx(bio, i)->bv_page; if (frombio) tx = async_memcpy(page, bio_page, page_offset, b_offset, clen, ASYNC_TX_DEP_ACK, tx, NULL, NULL); else tx = async_memcpy(bio_page, page, b_offset, page_offset, clen, ASYNC_TX_DEP_ACK, tx, NULL, NULL); } if (clen < len) /* hit end of page */ break; page_offset += len; } return tx; } static void ops_complete_biofill(void *stripe_head_ref) { struct stripe_head *sh = stripe_head_ref; struct bio *return_bi = NULL; raid5_conf_t *conf = sh->raid_conf; int i; pr_debug("%s: stripe %llu\n", __func__, (unsigned long long)sh->sector); /* clear completed biofills */ spin_lock_irq(&conf->device_lock); for (i = sh->disks; i--; ) { struct r5dev *dev = &sh->dev[i]; /* acknowledge completion of a biofill operation */ /* and check if we need to reply to a read request, * new R5_Wantfill requests are held off until * !STRIPE_BIOFILL_RUN */ if (test_and_clear_bit(R5_Wantfill, &dev->flags)) { struct bio *rbi, *rbi2; BUG_ON(!dev->read); rbi = dev->read; dev->read = NULL; while (rbi && rbi->bi_sector < dev->sector + STRIPE_SECTORS) { rbi2 = r5_next_bio(rbi, dev->sector); if (!raid5_dec_bi_phys_segments(rbi)) { rbi->bi_next = return_bi; return_bi = rbi; } rbi = rbi2; } } } spin_unlock_irq(&conf->device_lock); clear_bit(STRIPE_BIOFILL_RUN, &sh->state); return_io(return_bi); set_bit(STRIPE_HANDLE, &sh->state); release_stripe(sh); } static void ops_run_biofill(struct stripe_head *sh) { struct dma_async_tx_descriptor *tx = NULL; raid5_conf_t *conf = sh->raid_conf; int i; pr_debug("%s: stripe %llu\n", __func__, (unsigned long long)sh->sector); for (i = sh->disks; i--; ) { struct r5dev *dev = &sh->dev[i]; if (test_bit(R5_Wantfill, &dev->flags)) { struct bio *rbi; spin_lock_irq(&conf->device_lock); dev->read = rbi = dev->toread; dev->toread = NULL; spin_unlock_irq(&conf->device_lock); while (rbi && rbi->bi_sector < dev->sector + STRIPE_SECTORS) { tx = async_copy_data(0, rbi, dev->page, dev->sector, tx); rbi = r5_next_bio(rbi, dev->sector); } } } atomic_inc(&sh->count); async_trigger_callback(ASYNC_TX_DEP_ACK | ASYNC_TX_ACK, tx, ops_complete_biofill, sh); } static void ops_complete_compute5(void *stripe_head_ref) { struct stripe_head *sh = stripe_head_ref; int target = sh->ops.target; struct r5dev *tgt = &sh->dev[target]; pr_debug("%s: stripe %llu\n", __func__, (unsigned long long)sh->sector); set_bit(R5_UPTODATE, &tgt->flags); BUG_ON(!test_bit(R5_Wantcompute, &tgt->flags)); clear_bit(R5_Wantcompute, &tgt->flags); clear_bit(STRIPE_COMPUTE_RUN, &sh->state); if (sh->check_state == check_state_compute_run) sh->check_state = check_state_compute_result; set_bit(STRIPE_HANDLE, &sh->state); release_stripe(sh); } static struct dma_async_tx_descriptor *ops_run_compute5(struct stripe_head *sh) { /* kernel stack size limits the total number of disks */ int disks = sh->disks; struct page *xor_srcs[disks]; int target = sh->ops.target; struct r5dev *tgt = &sh->dev[target]; struct page *xor_dest = tgt->page; int count = 0; struct dma_async_tx_descriptor *tx; int i; pr_debug("%s: stripe %llu block: %d\n", __func__, (unsigned long long)sh->sector, target); BUG_ON(!test_bit(R5_Wantcompute, &tgt->flags)); for (i = disks; i--; ) if (i != target) xor_srcs[count++] = sh->dev[i].page; atomic_inc(&sh->count); if (unlikely(count == 1)) tx = async_memcpy(xor_dest, xor_srcs[0], 0, 0, STRIPE_SIZE, 0, NULL, ops_complete_compute5, sh); else tx = async_xor(xor_dest, xor_srcs, 0, count, STRIPE_SIZE, ASYNC_TX_XOR_ZERO_DST, NULL, ops_complete_compute5, sh); return tx; } static void ops_complete_prexor(void *stripe_head_ref) { struct stripe_head *sh = stripe_head_ref; pr_debug("%s: stripe %llu\n", __func__, (unsigned long long)sh->sector); } static struct dma_async_tx_descriptor * ops_run_prexor(struct stripe_head *sh, struct dma_async_tx_descriptor *tx) { /* kernel stack size limits the total number of disks */ int disks = sh->disks; struct page *xor_srcs[disks]; int count = 0, pd_idx = sh->pd_idx, i; /* existing parity data subtracted */ struct page *xor_dest = xor_srcs[count++] = sh->dev[pd_idx].page; pr_debug("%s: stripe %llu\n", __func__, (unsigned long long)sh->sector); for (i = disks; i--; ) { struct r5dev *dev = &sh->dev[i]; /* Only process blocks that are known to be uptodate */ if (test_bit(R5_Wantdrain, &dev->flags)) xor_srcs[count++] = dev->page; } tx = async_xor(xor_dest, xor_srcs, 0, count, STRIPE_SIZE, ASYNC_TX_DEP_ACK | ASYNC_TX_XOR_DROP_DST, tx, ops_complete_prexor, sh); return tx; } static struct dma_async_tx_descriptor * ops_run_biodrain(struct stripe_head *sh, struct dma_async_tx_descriptor *tx) { int disks = sh->disks; int i; pr_debug("%s: stripe %llu\n", __func__, (unsigned long long)sh->sector); for (i = disks; i--; ) { struct r5dev *dev = &sh->dev[i]; struct bio *chosen; if (test_and_clear_bit(R5_Wantdrain, &dev->flags)) { struct bio *wbi; spin_lock(&sh->lock); chosen = dev->towrite; dev->towrite = NULL; BUG_ON(dev->written); wbi = dev->written = chosen; spin_unlock(&sh->lock); while (wbi && wbi->bi_sector < dev->sector + STRIPE_SECTORS) { tx = async_copy_data(1, wbi, dev->page, dev->sector, tx); wbi = r5_next_bio(wbi, dev->sector); } } } return tx; } static void ops_complete_postxor(void *stripe_head_ref) { struct stripe_head *sh = stripe_head_ref; int disks = sh->disks, i, pd_idx = sh->pd_idx; pr_debug("%s: stripe %llu\n", __func__, (unsigned long long)sh->sector); for (i = disks; i--; ) { struct r5dev *dev = &sh->dev[i]; if (dev->written || i == pd_idx) set_bit(R5_UPTODATE, &dev->flags); } if (sh->reconstruct_state == reconstruct_state_drain_run) sh->reconstruct_state = reconstruct_state_drain_result; else if (sh->reconstruct_state == reconstruct_state_prexor_drain_run) sh->reconstruct_state = reconstruct_state_prexor_drain_result; else { BUG_ON(sh->reconstruct_state != reconstruct_state_run); sh->reconstruct_state = reconstruct_state_result; } set_bit(STRIPE_HANDLE, &sh->state); release_stripe(sh); } static void ops_run_postxor(struct stripe_head *sh, struct dma_async_tx_descriptor *tx) { /* kernel stack size limits the total number of disks */ int disks = sh->disks; struct page *xor_srcs[disks]; int count = 0, pd_idx = sh->pd_idx, i; struct page *xor_dest; int prexor = 0; unsigned long flags; pr_debug("%s: stripe %llu\n", __func__, (unsigned long long)sh->sector); /* check if prexor is active which means only process blocks * that are part of a read-modify-write (written) */ if (sh->reconstruct_state == reconstruct_state_prexor_drain_run) { prexor = 1; xor_dest = xor_srcs[count++] = sh->dev[pd_idx].page; for (i = disks; i--; ) { struct r5dev *dev = &sh->dev[i]; if (dev->written) xor_srcs[count++] = dev->page; } } else { xor_dest = sh->dev[pd_idx].page; for (i = disks; i--; ) { struct r5dev *dev = &sh->dev[i]; if (i != pd_idx) xor_srcs[count++] = dev->page; } } /* 1/ if we prexor'd then the dest is reused as a source * 2/ if we did not prexor then we are redoing the parity * set ASYNC_TX_XOR_DROP_DST and ASYNC_TX_XOR_ZERO_DST * for the synchronous xor case */ flags = ASYNC_TX_DEP_ACK | ASYNC_TX_ACK | (prexor ? ASYNC_TX_XOR_DROP_DST : ASYNC_TX_XOR_ZERO_DST); atomic_inc(&sh->count); if (unlikely(count == 1)) { flags &= ~(ASYNC_TX_XOR_DROP_DST | ASYNC_TX_XOR_ZERO_DST); tx = async_memcpy(xor_dest, xor_srcs[0], 0, 0, STRIPE_SIZE, flags, tx, ops_complete_postxor, sh); } else tx = async_xor(xor_dest, xor_srcs, 0, count, STRIPE_SIZE, flags, tx, ops_complete_postxor, sh); } static void ops_complete_check(void *stripe_head_ref) { struct stripe_head *sh = stripe_head_ref; pr_debug("%s: stripe %llu\n", __func__, (unsigned long long)sh->sector); sh->check_state = check_state_check_result; set_bit(STRIPE_HANDLE, &sh->state); release_stripe(sh); } static void ops_run_check(struct stripe_head *sh) { /* kernel stack size limits the total number of disks */ int disks = sh->disks; struct page *xor_srcs[disks]; struct dma_async_tx_descriptor *tx; int count = 0, pd_idx = sh->pd_idx, i; struct page *xor_dest = xor_srcs[count++] = sh->dev[pd_idx].page; pr_debug("%s: stripe %llu\n", __func__, (unsigned long long)sh->sector); for (i = disks; i--; ) { struct r5dev *dev = &sh->dev[i]; if (i != pd_idx) xor_srcs[count++] = dev->page; } tx = async_xor_zero_sum(xor_dest, xor_srcs, 0, count, STRIPE_SIZE, &sh->ops.zero_sum_result, 0, NULL, NULL, NULL); atomic_inc(&sh->count); tx = async_trigger_callback(ASYNC_TX_DEP_ACK | ASYNC_TX_ACK, tx, ops_complete_check, sh); } static void raid5_run_ops(struct stripe_head *sh, unsigned long ops_request) { int overlap_clear = 0, i, disks = sh->disks; struct dma_async_tx_descriptor *tx = NULL; if (test_bit(STRIPE_OP_BIOFILL, &ops_request)) { ops_run_biofill(sh); overlap_clear++; } if (test_bit(STRIPE_OP_COMPUTE_BLK, &ops_request)) { tx = ops_run_compute5(sh); /* terminate the chain if postxor is not set to be run */ if (tx && !test_bit(STRIPE_OP_POSTXOR, &ops_request)) async_tx_ack(tx); } if (test_bit(STRIPE_OP_PREXOR, &ops_request)) tx = ops_run_prexor(sh, tx); if (test_bit(STRIPE_OP_BIODRAIN, &ops_request)) { tx = ops_run_biodrain(sh, tx); overlap_clear++; } if (test_bit(STRIPE_OP_POSTXOR, &ops_request)) ops_run_postxor(sh, tx); if (test_bit(STRIPE_OP_CHECK, &ops_request)) ops_run_check(sh); if (overlap_clear) for (i = disks; i--; ) { struct r5dev *dev = &sh->dev[i]; if (test_and_clear_bit(R5_Overlap, &dev->flags)) wake_up(&sh->raid_conf->wait_for_overlap); } } static int grow_one_stripe(raid5_conf_t *conf) { struct stripe_head *sh; sh = kmem_cache_alloc(conf->slab_cache, GFP_KERNEL); if (!sh) return 0; memset(sh, 0, sizeof(*sh) + (conf->raid_disks-1)*sizeof(struct r5dev)); sh->raid_conf = conf; spin_lock_init(&sh->lock); if (grow_buffers(sh, conf->raid_disks)) { shrink_buffers(sh, conf->raid_disks); kmem_cache_free(conf->slab_cache, sh); return 0; } sh->disks = conf->raid_disks; /* we just created an active stripe so... */ atomic_set(&sh->count, 1); atomic_inc(&conf->active_stripes); INIT_LIST_HEAD(&sh->lru); release_stripe(sh); return 1; } static int grow_stripes(raid5_conf_t *conf, int num) { struct kmem_cache *sc; int devs = conf->raid_disks; sprintf(conf->cache_name[0], "raid%d-%s", conf->level, mdname(conf->mddev)); sprintf(conf->cache_name[1], "raid%d-%s-alt", conf->level, mdname(conf->mddev)); conf->active_name = 0; sc = kmem_cache_create(conf->cache_name[conf->active_name], sizeof(struct stripe_head)+(devs-1)*sizeof(struct r5dev), 0, 0, NULL); if (!sc) return 1; conf->slab_cache = sc; conf->pool_size = devs; while (num--) if (!grow_one_stripe(conf)) return 1; return 0; } static int resize_stripes(raid5_conf_t *conf, int newsize) { /* Make all the stripes able to hold 'newsize' devices. * New slots in each stripe get 'page' set to a new page. * * This happens in stages: * 1/ create a new kmem_cache and allocate the required number of * stripe_heads. * 2/ gather all the old stripe_heads and tranfer the pages across * to the new stripe_heads. This will have the side effect of * freezing the array as once all stripe_heads have been collected, * no IO will be possible. Old stripe heads are freed once their * pages have been transferred over, and the old kmem_cache is * freed when all stripes are done. * 3/ reallocate conf->disks to be suitable bigger. If this fails, * we simple return a failre status - no need to clean anything up. * 4/ allocate new pages for the new slots in the new stripe_heads. * If this fails, we don't bother trying the shrink the * stripe_heads down again, we just leave them as they are. * As each stripe_head is processed the new one is released into * active service. * * Once step2 is started, we cannot afford to wait for a write, * so we use GFP_NOIO allocations. */ struct stripe_head *osh, *nsh; LIST_HEAD(newstripes); struct disk_info *ndisks; int err; struct kmem_cache *sc; int i; if (newsize <= conf->pool_size) return 0; /* never bother to shrink */ err = md_allow_write(conf->mddev); if (err) return err; /* Step 1 */ sc = kmem_cache_create(conf->cache_name[1-conf->active_name], sizeof(struct stripe_head)+(newsize-1)*sizeof(struct r5dev), 0, 0, NULL); if (!sc) return -ENOMEM; for (i = conf->max_nr_stripes; i; i--) { nsh = kmem_cache_alloc(sc, GFP_KERNEL); if (!nsh) break; memset(nsh, 0, sizeof(*nsh) + (newsize-1)*sizeof(struct r5dev)); nsh->raid_conf = conf; spin_lock_init(&nsh->lock); list_add(&nsh->lru, &newstripes); } if (i) { /* didn't get enough, give up */ while (!list_empty(&newstripes)) { nsh = list_entry(newstripes.next, struct stripe_head, lru); list_del(&nsh->lru); kmem_cache_free(sc, nsh); } kmem_cache_destroy(sc); return -ENOMEM; } /* Step 2 - Must use GFP_NOIO now. * OK, we have enough stripes, start collecting inactive * stripes and copying them over */ list_for_each_entry(nsh, &newstripes, lru) { spin_lock_irq(&conf->device_lock); wait_event_lock_irq(conf->wait_for_stripe, !list_empty(&conf->inactive_list), conf->device_lock, unplug_slaves(conf->mddev) ); osh = get_free_stripe(conf); spin_unlock_irq(&conf->device_lock); atomic_set(&nsh->count, 1); for(i=0; ipool_size; i++) nsh->dev[i].page = osh->dev[i].page; for( ; idev[i].page = NULL; kmem_cache_free(conf->slab_cache, osh); } kmem_cache_destroy(conf->slab_cache); /* Step 3. * At this point, we are holding all the stripes so the array * is completely stalled, so now is a good time to resize * conf->disks. */ ndisks = kzalloc(newsize * sizeof(struct disk_info), GFP_NOIO); if (ndisks) { for (i=0; iraid_disks; i++) ndisks[i] = conf->disks[i]; kfree(conf->disks); conf->disks = ndisks; } else err = -ENOMEM; /* Step 4, return new stripes to service */ while(!list_empty(&newstripes)) { nsh = list_entry(newstripes.next, struct stripe_head, lru); list_del_init(&nsh->lru); for (i=conf->raid_disks; i < newsize; i++) if (nsh->dev[i].page == NULL) { struct page *p = alloc_page(GFP_NOIO); nsh->dev[i].page = p; if (!p) err = -ENOMEM; } release_stripe(nsh); } /* critical section pass, GFP_NOIO no longer needed */ conf->slab_cache = sc; conf->active_name = 1-conf->active_name; conf->pool_size = newsize; return err; } static int drop_one_stripe(raid5_conf_t *conf) { struct stripe_head *sh; spin_lock_irq(&conf->device_lock); sh = get_free_stripe(conf); spin_unlock_irq(&conf->device_lock); if (!sh) return 0; BUG_ON(atomic_read(&sh->count)); shrink_buffers(sh, conf->pool_size); kmem_cache_free(conf->slab_cache, sh); atomic_dec(&conf->active_stripes); return 1; } static void shrink_stripes(raid5_conf_t *conf) { while (drop_one_stripe(conf)) ; if (conf->slab_cache) kmem_cache_destroy(conf->slab_cache); conf->slab_cache = NULL; } static void raid5_end_read_request(struct bio * bi, int error) { struct stripe_head *sh = bi->bi_private; raid5_conf_t *conf = sh->raid_conf; int disks = sh->disks, i; int uptodate = test_bit(BIO_UPTODATE, &bi->bi_flags); char b[BDEVNAME_SIZE]; mdk_rdev_t *rdev; for (i=0 ; idev[i].req) break; pr_debug("end_read_request %llu/%d, count: %d, uptodate %d.\n", (unsigned long long)sh->sector, i, atomic_read(&sh->count), uptodate); if (i == disks) { BUG(); return; } if (uptodate) { set_bit(R5_UPTODATE, &sh->dev[i].flags); if (test_bit(R5_ReadError, &sh->dev[i].flags)) { rdev = conf->disks[i].rdev; printk_rl(KERN_INFO "raid5:%s: read error corrected" " (%lu sectors at %llu on %s)\n", mdname(conf->mddev), STRIPE_SECTORS, (unsigned long long)(sh->sector + rdev->data_offset), bdevname(rdev->bdev, b)); clear_bit(R5_ReadError, &sh->dev[i].flags); clear_bit(R5_ReWrite, &sh->dev[i].flags); } if (atomic_read(&conf->disks[i].rdev->read_errors)) atomic_set(&conf->disks[i].rdev->read_errors, 0); } else { const char *bdn = bdevname(conf->disks[i].rdev->bdev, b); int retry = 0; rdev = conf->disks[i].rdev; clear_bit(R5_UPTODATE, &sh->dev[i].flags); atomic_inc(&rdev->read_errors); if (conf->mddev->degraded) printk_rl(KERN_WARNING "raid5:%s: read error not correctable " "(sector %llu on %s).\n", mdname(conf->mddev), (unsigned long long)(sh->sector + rdev->data_offset), bdn); else if (test_bit(R5_ReWrite, &sh->dev[i].flags)) /* Oh, no!!! */ printk_rl(KERN_WARNING "raid5:%s: read error NOT corrected!! " "(sector %llu on %s).\n", mdname(conf->mddev), (unsigned long long)(sh->sector + rdev->data_offset), bdn); else if (atomic_read(&rdev->read_errors) > conf->max_nr_stripes) printk(KERN_WARNING "raid5:%s: Too many read errors, failing device %s.\n", mdname(conf->mddev), bdn); else retry = 1; if (retry) set_bit(R5_ReadError, &sh->dev[i].flags); else { clear_bit(R5_ReadError, &sh->dev[i].flags); clear_bit(R5_ReWrite, &sh->dev[i].flags); md_error(conf->mddev, rdev); } } rdev_dec_pending(conf->disks[i].rdev, conf->mddev); clear_bit(R5_LOCKED, &sh->dev[i].flags); set_bit(STRIPE_HANDLE, &sh->state); release_stripe(sh); } static void raid5_end_write_request(struct bio *bi, int error) { struct stripe_head *sh = bi->bi_private; raid5_conf_t *conf = sh->raid_conf; int disks = sh->disks, i; int uptodate = test_bit(BIO_UPTODATE, &bi->bi_flags); for (i=0 ; idev[i].req) break; pr_debug("end_write_request %llu/%d, count %d, uptodate: %d.\n", (unsigned long long)sh->sector, i, atomic_read(&sh->count), uptodate); if (i == disks) { BUG(); return; } if (!uptodate) md_error(conf->mddev, conf->disks[i].rdev); rdev_dec_pending(conf->disks[i].rdev, conf->mddev); clear_bit(R5_LOCKED, &sh->dev[i].flags); set_bit(STRIPE_HANDLE, &sh->state); release_stripe(sh); } static sector_t compute_blocknr(struct stripe_head *sh, int i, int previous); static void raid5_build_block(struct stripe_head *sh, int i, int previous) { struct r5dev *dev = &sh->dev[i]; bio_init(&dev->req); dev->req.bi_io_vec = &dev->vec; dev->req.bi_vcnt++; dev->req.bi_max_vecs++; dev->vec.bv_page = dev->page; dev->vec.bv_len = STRIPE_SIZE; dev->vec.bv_offset = 0; dev->req.bi_sector = sh->sector; dev->req.bi_private = sh; dev->flags = 0; dev->sector = compute_blocknr(sh, i, previous); } static void error(mddev_t *mddev, mdk_rdev_t *rdev) { char b[BDEVNAME_SIZE]; raid5_conf_t *conf = (raid5_conf_t *) mddev->private; pr_debug("raid5: error called\n"); if (!test_bit(Faulty, &rdev->flags)) { set_bit(MD_CHANGE_DEVS, &mddev->flags); if (test_and_clear_bit(In_sync, &rdev->flags)) { unsigned long flags; spin_lock_irqsave(&conf->device_lock, flags); mddev->degraded++; spin_unlock_irqrestore(&conf->device_lock, flags); /* * if recovery was running, make sure it aborts. */ set_bit(MD_RECOVERY_INTR, &mddev->recovery); } set_bit(Faulty, &rdev->flags); printk(KERN_ALERT "raid5: Disk failure on %s, disabling device.\n" "raid5: Operation continuing on %d devices.\n", bdevname(rdev->bdev,b), conf->raid_disks - mddev->degraded); } } /* * Input: a 'big' sector number, * Output: index of the data and parity disk, and the sector # in them. */ static sector_t raid5_compute_sector(raid5_conf_t *conf, sector_t r_sector, int previous, int *dd_idx, struct stripe_head *sh) { long stripe; unsigned long chunk_number; unsigned int chunk_offset; int pd_idx, qd_idx; int ddf_layout = 0; sector_t new_sector; int algorithm = previous ? conf->prev_algo : conf->algorithm; int sectors_per_chunk = previous ? (conf->prev_chunk >> 9) : (conf->chunk_size >> 9); int raid_disks = previous ? conf->previous_raid_disks : conf->raid_disks; int data_disks = raid_disks - conf->max_degraded; /* First compute the information on this sector */ /* * Compute the chunk number and the sector offset inside the chunk */ chunk_offset = sector_div(r_sector, sectors_per_chunk); chunk_number = r_sector; BUG_ON(r_sector != chunk_number); /* * Compute the stripe number */ stripe = chunk_number / data_disks; /* * Compute the data disk and parity disk indexes inside the stripe */ *dd_idx = chunk_number % data_disks; /* * Select the parity disk based on the user selected algorithm. */ pd_idx = qd_idx = ~0; switch(conf->level) { case 4: pd_idx = data_disks; break; case 5: switch (algorithm) { case ALGORITHM_LEFT_ASYMMETRIC: pd_idx = data_disks - stripe % raid_disks; if (*dd_idx >= pd_idx) (*dd_idx)++; break; case ALGORITHM_RIGHT_ASYMMETRIC: pd_idx = stripe % raid_disks; if (*dd_idx >= pd_idx) (*dd_idx)++; break; case ALGORITHM_LEFT_SYMMETRIC: pd_idx = data_disks - stripe % raid_disks; *dd_idx = (pd_idx + 1 + *dd_idx) % raid_disks; break; case ALGORITHM_RIGHT_SYMMETRIC: pd_idx = stripe % raid_disks; *dd_idx = (pd_idx + 1 + *dd_idx) % raid_disks; break; case ALGORITHM_PARITY_0: pd_idx = 0; (*dd_idx)++; break; case ALGORITHM_PARITY_N: pd_idx = data_disks; break; default: printk(KERN_ERR "raid5: unsupported algorithm %d\n", algorithm); BUG(); } break; case 6: switch (algorithm) { case ALGORITHM_LEFT_ASYMMETRIC: pd_idx = raid_disks - 1 - (stripe % raid_disks); qd_idx = pd_idx + 1; if (pd_idx == raid_disks-1) { (*dd_idx)++; /* Q D D D P */ qd_idx = 0; } else if (*dd_idx >= pd_idx) (*dd_idx) += 2; /* D D P Q D */ break; case ALGORITHM_RIGHT_ASYMMETRIC: pd_idx = stripe % raid_disks; qd_idx = pd_idx + 1; if (pd_idx == raid_disks-1) { (*dd_idx)++; /* Q D D D P */ qd_idx = 0; } else if (*dd_idx >= pd_idx) (*dd_idx) += 2; /* D D P Q D */ break; case ALGORITHM_LEFT_SYMMETRIC: pd_idx = raid_disks - 1 - (stripe % raid_disks); qd_idx = (pd_idx + 1) % raid_disks; *dd_idx = (pd_idx + 2 + *dd_idx) % raid_disks; break; case ALGORITHM_RIGHT_SYMMETRIC: pd_idx = stripe % raid_disks; qd_idx = (pd_idx + 1) % raid_disks; *dd_idx = (pd_idx + 2 + *dd_idx) % raid_disks; break; case ALGORITHM_PARITY_0: pd_idx = 0; qd_idx = 1; (*dd_idx) += 2; break; case ALGORITHM_PARITY_N: pd_idx = data_disks; qd_idx = data_disks + 1; break; case ALGORITHM_ROTATING_ZERO_RESTART: /* Exactly the same as RIGHT_ASYMMETRIC, but or * of blocks for computing Q is different. */ pd_idx = stripe % raid_disks; qd_idx = pd_idx + 1; if (pd_idx == raid_disks-1) { (*dd_idx)++; /* Q D D D P */ qd_idx = 0; } else if (*dd_idx >= pd_idx) (*dd_idx) += 2; /* D D P Q D */ ddf_layout = 1; break; case ALGORITHM_ROTATING_N_RESTART: /* Same a left_asymmetric, by first stripe is * D D D P Q rather than * Q D D D P */ pd_idx = raid_disks - 1 - ((stripe + 1) % raid_disks); qd_idx = pd_idx + 1; if (pd_idx == raid_disks-1) { (*dd_idx)++; /* Q D D D P */ qd_idx = 0; } else if (*dd_idx >= pd_idx) (*dd_idx) += 2; /* D D P Q D */ ddf_layout = 1; break; case ALGORITHM_ROTATING_N_CONTINUE: /* Same as left_symmetric but Q is before P */ pd_idx = raid_disks - 1 - (stripe % raid_disks); qd_idx = (pd_idx + raid_disks - 1) % raid_disks; *dd_idx = (pd_idx + 1 + *dd_idx) % raid_disks; ddf_layout = 1; break; case ALGORITHM_LEFT_ASYMMETRIC_6: /* RAID5 left_asymmetric, with Q on last device */ pd_idx = data_disks - stripe % (raid_disks-1); if (*dd_idx >= pd_idx) (*dd_idx)++; qd_idx = raid_disks - 1; break; case ALGORITHM_RIGHT_ASYMMETRIC_6: pd_idx = stripe % (raid_disks-1); if (*dd_idx >= pd_idx) (*dd_idx)++; qd_idx = raid_disks - 1; break; case ALGORITHM_LEFT_SYMMETRIC_6: pd_idx = data_disks - stripe % (raid_disks-1); *dd_idx = (pd_idx + 1 + *dd_idx) % (raid_disks-1); qd_idx = raid_disks - 1; break; case ALGORITHM_RIGHT_SYMMETRIC_6: pd_idx = stripe % (raid_disks-1); *dd_idx = (pd_idx + 1 + *dd_idx) % (raid_disks-1); qd_idx = raid_disks - 1; break; case ALGORITHM_PARITY_0_6: pd_idx = 0; (*dd_idx)++; qd_idx = raid_disks - 1; break; default: printk(KERN_CRIT "raid6: unsupported algorithm %d\n", algorithm); BUG(); } break; } if (sh) { sh->pd_idx = pd_idx; sh->qd_idx = qd_idx; sh->ddf_layout = ddf_layout; } /* * Finally, compute the new sector number */ new_sector = (sector_t)stripe * sectors_per_chunk + chunk_offset; return new_sector; } static sector_t compute_blocknr(struct stripe_head *sh, int i, int previous) { raid5_conf_t *conf = sh->raid_conf; int raid_disks = sh->disks; int data_disks = raid_disks - conf->max_degraded; sector_t new_sector = sh->sector, check; int sectors_per_chunk = previous ? (conf->prev_chunk >> 9) : (conf->chunk_size >> 9); int algorithm = previous ? conf->prev_algo : conf->algorithm; sector_t stripe; int chunk_offset; int chunk_number, dummy1, dd_idx = i; sector_t r_sector; struct stripe_head sh2; chunk_offset = sector_div(new_sector, sectors_per_chunk); stripe = new_sector; BUG_ON(new_sector != stripe); if (i == sh->pd_idx) return 0; switch(conf->level) { case 4: break; case 5: switch (algorithm) { case ALGORITHM_LEFT_ASYMMETRIC: case ALGORITHM_RIGHT_ASYMMETRIC: if (i > sh->pd_idx) i--; break; case ALGORITHM_LEFT_SYMMETRIC: case ALGORITHM_RIGHT_SYMMETRIC: if (i < sh->pd_idx) i += raid_disks; i -= (sh->pd_idx + 1); break; case ALGORITHM_PARITY_0: i -= 1; break; case ALGORITHM_PARITY_N: break; default: printk(KERN_ERR "raid5: unsupported algorithm %d\n", algorithm); BUG(); } break; case 6: if (i == sh->qd_idx) return 0; /* It is the Q disk */ switch (algorithm) { case ALGORITHM_LEFT_ASYMMETRIC: case ALGORITHM_RIGHT_ASYMMETRIC: case ALGORITHM_ROTATING_ZERO_RESTART: case ALGORITHM_ROTATING_N_RESTART: if (sh->pd_idx == raid_disks-1) i--; /* Q D D D P */ else if (i > sh->pd_idx) i -= 2; /* D D P Q D */ break; case ALGORITHM_LEFT_SYMMETRIC: case ALGORITHM_RIGHT_SYMMETRIC: if (sh->pd_idx == raid_disks-1) i--; /* Q D D D P */ else { /* D D P Q D */ if (i < sh->pd_idx) i += raid_disks; i -= (sh->pd_idx + 2); } break; case ALGORITHM_PARITY_0: i -= 2; break; case ALGORITHM_PARITY_N: break; case ALGORITHM_ROTATING_N_CONTINUE: if (sh->pd_idx == 0) i--; /* P D D D Q */ else if (i > sh->pd_idx) i -= 2; /* D D Q P D */ break; case ALGORITHM_LEFT_ASYMMETRIC_6: case ALGORITHM_RIGHT_ASYMMETRIC_6: if (i > sh->pd_idx) i--; break; case ALGORITHM_LEFT_SYMMETRIC_6: case ALGORITHM_RIGHT_SYMMETRIC_6: if (i < sh->pd_idx) i += data_disks + 1; i -= (sh->pd_idx + 1); break; case ALGORITHM_PARITY_0_6: i -= 1; break; default: printk(KERN_CRIT "raid6: unsupported algorithm %d\n", algorithm); BUG(); } break; } chunk_number = stripe * data_disks + i; r_sector = (sector_t)chunk_number * sectors_per_chunk + chunk_offset; check = raid5_compute_sector(conf, r_sector, previous, &dummy1, &sh2); if (check != sh->sector || dummy1 != dd_idx || sh2.pd_idx != sh->pd_idx || sh2.qd_idx != sh->qd_idx) { printk(KERN_ERR "compute_blocknr: map not correct\n"); return 0; } return r_sector; } /* * Copy data between a page in the stripe cache, and one or more bion * The page could align with the middle of the bio, or there could be * several bion, each with several bio_vecs, which cover part of the page * Multiple bion are linked together on bi_next. There may be extras * at the end of this list. We ignore them. */ static void copy_data(int frombio, struct bio *bio, struct page *page, sector_t sector) { char *pa = page_address(page); struct bio_vec *bvl; int i; int page_offset; if (bio->bi_sector >= sector) page_offset = (signed)(bio->bi_sector - sector) * 512; else page_offset = (signed)(sector - bio->bi_sector) * -512; bio_for_each_segment(bvl, bio, i) { int len = bio_iovec_idx(bio,i)->bv_len; int clen; int b_offset = 0; if (page_offset < 0) { b_offset = -page_offset; page_offset += b_offset; len -= b_offset; } if (len > 0 && page_offset + len > STRIPE_SIZE) clen = STRIPE_SIZE - page_offset; else clen = len; if (clen > 0) { char *ba = __bio_kmap_atomic(bio, i, KM_USER0); if (frombio) memcpy(pa+page_offset, ba+b_offset, clen); else memcpy(ba+b_offset, pa+page_offset, clen); __bio_kunmap_atomic(ba, KM_USER0); } if (clen < len) /* hit end of page */ break; page_offset += len; } } #define check_xor() do { \ if (count == MAX_XOR_BLOCKS) { \ xor_blocks(count, STRIPE_SIZE, dest, ptr);\ count = 0; \ } \ } while(0) static void compute_parity6(struct stripe_head *sh, int method) { raid5_conf_t *conf = sh->raid_conf; int i, pd_idx, qd_idx, d0_idx, disks = sh->disks, count; int syndrome_disks = sh->ddf_layout ? disks : (disks - 2); struct bio *chosen; /**** FIX THIS: This could be very bad if disks is close to 256 ****/ void *ptrs[syndrome_disks+2]; pd_idx = sh->pd_idx; qd_idx = sh->qd_idx; d0_idx = raid6_d0(sh); pr_debug("compute_parity, stripe %llu, method %d\n", (unsigned long long)sh->sector, method); switch(method) { case READ_MODIFY_WRITE: BUG(); /* READ_MODIFY_WRITE N/A for RAID-6 */ case RECONSTRUCT_WRITE: for (i= disks; i-- ;) if ( i != pd_idx && i != qd_idx && sh->dev[i].towrite ) { chosen = sh->dev[i].towrite; sh->dev[i].towrite = NULL; if (test_and_clear_bit(R5_Overlap, &sh->dev[i].flags)) wake_up(&conf->wait_for_overlap); BUG_ON(sh->dev[i].written); sh->dev[i].written = chosen; } break; case CHECK_PARITY: BUG(); /* Not implemented yet */ } for (i = disks; i--;) if (sh->dev[i].written) { sector_t sector = sh->dev[i].sector; struct bio *wbi = sh->dev[i].written; while (wbi && wbi->bi_sector < sector + STRIPE_SECTORS) { copy_data(1, wbi, sh->dev[i].page, sector); wbi = r5_next_bio(wbi, sector); } set_bit(R5_LOCKED, &sh->dev[i].flags); set_bit(R5_UPTODATE, &sh->dev[i].flags); } /* Note that unlike RAID-5, the ordering of the disks matters greatly.*/ for (i = 0; i < disks; i++) ptrs[i] = (void *)raid6_empty_zero_page; count = 0; i = d0_idx; do { int slot = raid6_idx_to_slot(i, sh, &count, syndrome_disks); ptrs[slot] = page_address(sh->dev[i].page); if (slot < syndrome_disks && !test_bit(R5_UPTODATE, &sh->dev[i].flags)) { printk(KERN_ERR "block %d/%d not uptodate " "on parity calc\n", i, count); BUG(); } i = raid6_next_disk(i, disks); } while (i != d0_idx); BUG_ON(count != syndrome_disks); raid6_call.gen_syndrome(syndrome_disks+2, STRIPE_SIZE, ptrs); switch(method) { case RECONSTRUCT_WRITE: set_bit(R5_UPTODATE, &sh->dev[pd_idx].flags); set_bit(R5_UPTODATE, &sh->dev[qd_idx].flags); set_bit(R5_LOCKED, &sh->dev[pd_idx].flags); set_bit(R5_LOCKED, &sh->dev[qd_idx].flags); break; case UPDATE_PARITY: set_bit(R5_UPTODATE, &sh->dev[pd_idx].flags); set_bit(R5_UPTODATE, &sh->dev[qd_idx].flags); break; } } /* Compute one missing block */ static void compute_block_1(struct stripe_head *sh, int dd_idx, int nozero) { int i, count, disks = sh->disks; void *ptr[MAX_XOR_BLOCKS], *dest, *p; int qd_idx = sh->qd_idx; pr_debug("compute_block_1, stripe %llu, idx %d\n", (unsigned long long)sh->sector, dd_idx); if ( dd_idx == qd_idx ) { /* We're actually computing the Q drive */ compute_parity6(sh, UPDATE_PARITY); } else { dest = page_address(sh->dev[dd_idx].page); if (!nozero) memset(dest, 0, STRIPE_SIZE); count = 0; for (i = disks ; i--; ) { if (i == dd_idx || i == qd_idx) continue; p = page_address(sh->dev[i].page); if (test_bit(R5_UPTODATE, &sh->dev[i].flags)) ptr[count++] = p; else printk("compute_block() %d, stripe %llu, %d" " not present\n", dd_idx, (unsigned long long)sh->sector, i); check_xor(); } if (count) xor_blocks(count, STRIPE_SIZE, dest, ptr); if (!nozero) set_bit(R5_UPTODATE, &sh->dev[dd_idx].flags); else clear_bit(R5_UPTODATE, &sh->dev[dd_idx].flags); } } /* Compute two missing blocks */ static void compute_block_2(struct stripe_head *sh, int dd_idx1, int dd_idx2) { int i, count, disks = sh->disks; int syndrome_disks = sh->ddf_layout ? disks : disks-2; int d0_idx = raid6_d0(sh); int faila = -1, failb = -1; /**** FIX THIS: This could be very bad if disks is close to 256 ****/ void *ptrs[syndrome_disks+2]; for (i = 0; i < disks ; i++) ptrs[i] = (void *)raid6_empty_zero_page; count = 0; i = d0_idx; do { int slot = raid6_idx_to_slot(i, sh, &count, syndrome_disks); ptrs[slot] = page_address(sh->dev[i].page); if (i == dd_idx1) faila = slot; if (i == dd_idx2) failb = slot; i = raid6_next_disk(i, disks); } while (i != d0_idx); BUG_ON(count != syndrome_disks); BUG_ON(faila == failb); if ( failb < faila ) { int tmp = faila; faila = failb; failb = tmp; } pr_debug("compute_block_2, stripe %llu, idx %d,%d (%d,%d)\n", (unsigned long long)sh->sector, dd_idx1, dd_idx2, faila, failb); if (failb == syndrome_disks+1) { /* Q disk is one of the missing disks */ if (faila == syndrome_disks) { /* Missing P+Q, just recompute */ compute_parity6(sh, UPDATE_PARITY); return; } else { /* We're missing D+Q; recompute D from P */ compute_block_1(sh, ((dd_idx1 == sh->qd_idx) ? dd_idx2 : dd_idx1), 0); compute_parity6(sh, UPDATE_PARITY); /* Is this necessary? */ return; } } /* We're missing D+P or D+D; */ if (failb == syndrome_disks) { /* We're missing D+P. */ raid6_datap_recov(syndrome_disks+2, STRIPE_SIZE, faila, ptrs); } else { /* We're missing D+D. */ raid6_2data_recov(syndrome_disks+2, STRIPE_SIZE, faila, failb, ptrs); } /* Both the above update both missing blocks */ set_bit(R5_UPTODATE, &sh->dev[dd_idx1].flags); set_bit(R5_UPTODATE, &sh->dev[dd_idx2].flags); } static void schedule_reconstruction5(struct stripe_head *sh, struct stripe_head_state *s, int rcw, int expand) { int i, pd_idx = sh->pd_idx, disks = sh->disks; if (rcw) { /* if we are not expanding this is a proper write request, and * there will be bios with new data to be drained into the * stripe cache */ if (!expand) { sh->reconstruct_state = reconstruct_state_drain_run; set_bit(STRIPE_OP_BIODRAIN, &s->ops_request); } else sh->reconstruct_state = reconstruct_state_run; set_bit(STRIPE_OP_POSTXOR, &s->ops_request); for (i = disks; i--; ) { struct r5dev *dev = &sh->dev[i]; if (dev->towrite) { set_bit(R5_LOCKED, &dev->flags); set_bit(R5_Wantdrain, &dev->flags); if (!expand) clear_bit(R5_UPTODATE, &dev->flags); s->locked++; } } if (s->locked + 1 == disks) if (!test_and_set_bit(STRIPE_FULL_WRITE, &sh->state)) atomic_inc(&sh->raid_conf->pending_full_writes); } else { BUG_ON(!(test_bit(R5_UPTODATE, &sh->dev[pd_idx].flags) || test_bit(R5_Wantcompute, &sh->dev[pd_idx].flags))); sh->reconstruct_state = reconstruct_state_prexor_drain_run; set_bit(STRIPE_OP_PREXOR, &s->ops_request); set_bit(STRIPE_OP_BIODRAIN, &s->ops_request); set_bit(STRIPE_OP_POSTXOR, &s->ops_request); for (i = disks; i--; ) { struct r5dev *dev = &sh->dev[i]; if (i == pd_idx) continue; if (dev->towrite && (test_bit(R5_UPTODATE, &dev->flags) || test_bit(R5_Wantcompute, &dev->flags))) { set_bit(R5_Wantdrain, &dev->flags); set_bit(R5_LOCKED, &dev->flags); clear_bit(R5_UPTODATE, &dev->flags); s->locked++; } } } /* keep the parity disk locked while asynchronous operations * are in flight */ set_bit(R5_LOCKED, &sh->dev[pd_idx].flags); clear_bit(R5_UPTODATE, &sh->dev[pd_idx].flags); s->locked++; pr_debug("%s: stripe %llu locked: %d ops_request: %lx\n", __func__, (unsigned long long)sh->sector, s->locked, s->ops_request); } /* * Each stripe/dev can have one or more bion attached. * toread/towrite point to the first in a chain. * The bi_next chain must be in order. */ static int add_stripe_bio(struct stripe_head *sh, struct bio *bi, int dd_idx, int forwrite) { struct bio **bip; raid5_conf_t *conf = sh->raid_conf; int firstwrite=0; pr_debug("adding bh b#%llu to stripe s#%llu\n", (unsigned long long)bi->bi_sector, (unsigned long long)sh->sector); spin_lock(&sh->lock); spin_lock_irq(&conf->device_lock); if (forwrite) { bip = &sh->dev[dd_idx].towrite; if (*bip == NULL && sh->dev[dd_idx].written == NULL) firstwrite = 1; } else bip = &sh->dev[dd_idx].toread; while (*bip && (*bip)->bi_sector < bi->bi_sector) { if ((*bip)->bi_sector + ((*bip)->bi_size >> 9) > bi->bi_sector) goto overlap; bip = & (*bip)->bi_next; } if (*bip && (*bip)->bi_sector < bi->bi_sector + ((bi->bi_size)>>9)) goto overlap; BUG_ON(*bip && bi->bi_next && (*bip) != bi->bi_next); if (*bip) bi->bi_next = *bip; *bip = bi; bi->bi_phys_segments++; spin_unlock_irq(&conf->device_lock); spin_unlock(&sh->lock); pr_debug("added bi b#%llu to stripe s#%llu, disk %d.\n", (unsigned long long)bi->bi_sector, (unsigned long long)sh->sector, dd_idx); if (conf->mddev->bitmap && firstwrite) { bitmap_startwrite(conf->mddev->bitmap, sh->sector, STRIPE_SECTORS, 0); sh->bm_seq = conf->seq_flush+1; set_bit(STRIPE_BIT_DELAY, &sh->state); } if (forwrite) { /* check if page is covered */ sector_t sector = sh->dev[dd_idx].sector; for (bi=sh->dev[dd_idx].towrite; sector < sh->dev[dd_idx].sector + STRIPE_SECTORS && bi && bi->bi_sector <= sector; bi = r5_next_bio(bi, sh->dev[dd_idx].sector)) { if (bi->bi_sector + (bi->bi_size>>9) >= sector) sector = bi->bi_sector + (bi->bi_size>>9); } if (sector >= sh->dev[dd_idx].sector + STRIPE_SECTORS) set_bit(R5_OVERWRITE, &sh->dev[dd_idx].flags); } return 1; overlap: set_bit(R5_Overlap, &sh->dev[dd_idx].flags); spin_unlock_irq(&conf->device_lock); spin_unlock(&sh->lock); return 0; } static void end_reshape(raid5_conf_t *conf); static int page_is_zero(struct page *p) { char *a = page_address(p); return ((*(u32*)a) == 0 && memcmp(a, a+4, STRIPE_SIZE-4)==0); } static void stripe_set_idx(sector_t stripe, raid5_conf_t *conf, int previous, struct stripe_head *sh) { int sectors_per_chunk = previous ? (conf->prev_chunk >> 9) : (conf->chunk_size >> 9); int dd_idx; int chunk_offset = sector_div(stripe, sectors_per_chunk); int disks = previous ? conf->previous_raid_disks : conf->raid_disks; raid5_compute_sector(conf, stripe * (disks - conf->max_degraded) *sectors_per_chunk + chunk_offset, previous, &dd_idx, sh); } static void handle_failed_stripe(raid5_conf_t *conf, struct stripe_head *sh, struct stripe_head_state *s, int disks, struct bio **return_bi) { int i; for (i = disks; i--; ) { struct bio *bi; int bitmap_end = 0; if (test_bit(R5_ReadError, &sh->dev[i].flags)) { mdk_rdev_t *rdev; rcu_read_lock(); rdev = rcu_dereference(conf->disks[i].rdev); if (rdev && test_bit(In_sync, &rdev->flags)) /* multiple read failures in one stripe */ md_error(conf->mddev, rdev); rcu_read_unlock(); } spin_lock_irq(&conf->device_lock); /* fail all writes first */ bi = sh->dev[i].towrite; sh->dev[i].towrite = NULL; if (bi) { s->to_write--; bitmap_end = 1; } if (test_and_clear_bit(R5_Overlap, &sh->dev[i].flags)) wake_up(&conf->wait_for_overlap); while (bi && bi->bi_sector < sh->dev[i].sector + STRIPE_SECTORS) { struct bio *nextbi = r5_next_bio(bi, sh->dev[i].sector); clear_bit(BIO_UPTODATE, &bi->bi_flags); if (!raid5_dec_bi_phys_segments(bi)) { md_write_end(conf->mddev); bi->bi_next = *return_bi; *return_bi = bi; } bi = nextbi; } /* and fail all 'written' */ bi = sh->dev[i].written; sh->dev[i].written = NULL; if (bi) bitmap_end = 1; while (bi && bi->bi_sector < sh->dev[i].sector + STRIPE_SECTORS) { struct bio *bi2 = r5_next_bio(bi, sh->dev[i].sector); clear_bit(BIO_UPTODATE, &bi->bi_flags); if (!raid5_dec_bi_phys_segments(bi)) { md_write_end(conf->mddev); bi->bi_next = *return_bi; *return_bi = bi; } bi = bi2; } /* fail any reads if this device is non-operational and * the data has not reached the cache yet. */ if (!test_bit(R5_Wantfill, &sh->dev[i].flags) && (!test_bit(R5_Insync, &sh->dev[i].flags) || test_bit(R5_ReadError, &sh->dev[i].flags))) { bi = sh->dev[i].toread; sh->dev[i].toread = NULL; if (test_and_clear_bit(R5_Overlap, &sh->dev[i].flags)) wake_up(&conf->wait_for_overlap); if (bi) s->to_read--; while (bi && bi->bi_sector < sh->dev[i].sector + STRIPE_SECTORS) { struct bio *nextbi = r5_next_bio(bi, sh->dev[i].sector); clear_bit(BIO_UPTODATE, &bi->bi_flags); if (!raid5_dec_bi_phys_segments(bi)) { bi->bi_next = *return_bi; *return_bi = bi; } bi = nextbi; } } spin_unlock_irq(&conf->device_lock); if (bitmap_end) bitmap_endwrite(conf->mddev->bitmap, sh->sector, STRIPE_SECTORS, 0, 0); } if (test_and_clear_bit(STRIPE_FULL_WRITE, &sh->state)) if (atomic_dec_and_test(&conf->pending_full_writes)) md_wakeup_thread(conf->mddev->thread); } /* fetch_block5 - checks the given member device to see if its data needs * to be read or computed to satisfy a request. * * Returns 1 when no more member devices need to be checked, otherwise returns * 0 to tell the loop in handle_stripe_fill5 to continue */ static int fetch_block5(struct stripe_head *sh, struct stripe_head_state *s, int disk_idx, int disks) { struct r5dev *dev = &sh->dev[disk_idx]; struct r5dev *failed_dev = &sh->dev[s->failed_num]; /* is the data in this block needed, and can we get it? */ if (!test_bit(R5_LOCKED, &dev->flags) && !test_bit(R5_UPTODATE, &dev->flags) && (dev->toread || (dev->towrite && !test_bit(R5_OVERWRITE, &dev->flags)) || s->syncing || s->expanding || (s->failed && (failed_dev->toread || (failed_dev->towrite && !test_bit(R5_OVERWRITE, &failed_dev->flags)))))) { /* We would like to get this block, possibly by computing it, * otherwise read it if the backing disk is insync */ if ((s->uptodate == disks - 1) && (s->failed && disk_idx == s->failed_num)) { set_bit(STRIPE_COMPUTE_RUN, &sh->state); set_bit(STRIPE_OP_COMPUTE_BLK, &s->ops_request); set_bit(R5_Wantcompute, &dev->flags); sh->ops.target = disk_idx; s->req_compute = 1; /* Careful: from this point on 'uptodate' is in the eye * of raid5_run_ops which services 'compute' operations * before writes. R5_Wantcompute flags a block that will * be R5_UPTODATE by the time it is needed for a * subsequent operation. */ s->uptodate++; return 1; /* uptodate + compute == disks */ } else if (test_bit(R5_Insync, &dev->flags)) { set_bit(R5_LOCKED, &dev->flags); set_bit(R5_Wantread, &dev->flags); s->locked++; pr_debug("Reading block %d (sync=%d)\n", disk_idx, s->syncing); } } return 0; } /** * handle_stripe_fill5 - read or compute data to satisfy pending requests. */ static void handle_stripe_fill5(struct stripe_head *sh, struct stripe_head_state *s, int disks) { int i; /* look for blocks to read/compute, skip this if a compute * is already in flight, or if the stripe contents are in the * midst of changing due to a write */ if (!test_bit(STRIPE_COMPUTE_RUN, &sh->state) && !sh->check_state && !sh->reconstruct_state) for (i = disks; i--; ) if (fetch_block5(sh, s, i, disks)) break; set_bit(STRIPE_HANDLE, &sh->state); } static void handle_stripe_fill6(struct stripe_head *sh, struct stripe_head_state *s, struct r6_state *r6s, int disks) { int i; for (i = disks; i--; ) { struct r5dev *dev = &sh->dev[i]; if (!test_bit(R5_LOCKED, &dev->flags) && !test_bit(R5_UPTODATE, &dev->flags) && (dev->toread || (dev->towrite && !test_bit(R5_OVERWRITE, &dev->flags)) || s->syncing || s->expanding || (s->failed >= 1 && (sh->dev[r6s->failed_num[0]].toread || s->to_write)) || (s->failed >= 2 && (sh->dev[r6s->failed_num[1]].toread || s->to_write)))) { /* we would like to get this block, possibly * by computing it, but we might not be able to */ if ((s->uptodate == disks - 1) && (s->failed && (i == r6s->failed_num[0] || i == r6s->failed_num[1]))) { pr_debug("Computing stripe %llu block %d\n", (unsigned long long)sh->sector, i); compute_block_1(sh, i, 0); s->uptodate++; } else if ( s->uptodate == disks-2 && s->failed >= 2 ) { /* Computing 2-failure is *very* expensive; only * do it if failed >= 2 */ int other; for (other = disks; other--; ) { if (other == i) continue; if (!test_bit(R5_UPTODATE, &sh->dev[other].flags)) break; } BUG_ON(other < 0); pr_debug("Computing stripe %llu blocks %d,%d\n", (unsigned long long)sh->sector, i, other); compute_block_2(sh, i, other); s->uptodate += 2; } else if (test_bit(R5_Insync, &dev->flags)) { set_bit(R5_LOCKED, &dev->flags); set_bit(R5_Wantread, &dev->flags); s->locked++; pr_debug("Reading block %d (sync=%d)\n", i, s->syncing); } } } set_bit(STRIPE_HANDLE, &sh->state); } /* handle_stripe_clean_event * any written block on an uptodate or failed drive can be returned. * Note that if we 'wrote' to a failed drive, it will be UPTODATE, but * never LOCKED, so we don't need to test 'failed' directly. */ static void handle_stripe_clean_event(raid5_conf_t *conf, struct stripe_head *sh, int disks, struct bio **return_bi) { int i; struct r5dev *dev; for (i = disks; i--; ) if (sh->dev[i].written) { dev = &sh->dev[i]; if (!test_bit(R5_LOCKED, &dev->flags) && test_bit(R5_UPTODATE, &dev->flags)) { /* We can return any write requests */ struct bio *wbi, *wbi2; int bitmap_end = 0; pr_debug("Return write for disc %d\n", i); spin_lock_irq(&conf->device_lock); wbi = dev->written; dev->written = NULL; while (wbi && wbi->bi_sector < dev->sector + STRIPE_SECTORS) { wbi2 = r5_next_bio(wbi, dev->sector); if (!raid5_dec_bi_phys_segments(wbi)) { md_write_end(conf->mddev); wbi->bi_next = *return_bi; *return_bi = wbi; } wbi = wbi2; } if (dev->towrite == NULL) bitmap_end = 1; spin_unlock_irq(&conf->device_lock); if (bitmap_end) bitmap_endwrite(conf->mddev->bitmap, sh->sector, STRIPE_SECTORS, !test_bit(STRIPE_DEGRADED, &sh->state), 0); } } if (test_and_clear_bit(STRIPE_FULL_WRITE, &sh->state)) if (atomic_dec_and_test(&conf->pending_full_writes)) md_wakeup_thread(conf->mddev->thread); } static void handle_stripe_dirtying5(raid5_conf_t *conf, struct stripe_head *sh, struct stripe_head_state *s, int disks) { int rmw = 0, rcw = 0, i; for (i = disks; i--; ) { /* would I have to read this buffer for read_modify_write */ struct r5dev *dev = &sh->dev[i]; if ((dev->towrite || i == sh->pd_idx) && !test_bit(R5_LOCKED, &dev->flags) && !(test_bit(R5_UPTODATE, &dev->flags) || test_bit(R5_Wantcompute, &dev->flags))) { if (test_bit(R5_Insync, &dev->flags)) rmw++; else rmw += 2*disks; /* cannot read it */ } /* Would I have to read this buffer for reconstruct_write */ if (!test_bit(R5_OVERWRITE, &dev->flags) && i != sh->pd_idx && !test_bit(R5_LOCKED, &dev->flags) && !(test_bit(R5_UPTODATE, &dev->flags) || test_bit(R5_Wantcompute, &dev->flags))) { if (test_bit(R5_Insync, &dev->flags)) rcw++; else rcw += 2*disks; } } pr_debug("for sector %llu, rmw=%d rcw=%d\n", (unsigned long long)sh->sector, rmw, rcw); set_bit(STRIPE_HANDLE, &sh->state); if (rmw < rcw && rmw > 0) /* prefer read-modify-write, but need to get some data */ for (i = disks; i--; ) { struct r5dev *dev = &sh->dev[i]; if ((dev->towrite || i == sh->pd_idx) && !test_bit(R5_LOCKED, &dev->flags) && !(test_bit(R5_UPTODATE, &dev->flags) || test_bit(R5_Wantcompute, &dev->flags)) && test_bit(R5_Insync, &dev->flags)) { if ( test_bit(STRIPE_PREREAD_ACTIVE, &sh->state)) { pr_debug("Read_old block " "%d for r-m-w\n", i); set_bit(R5_LOCKED, &dev->flags); set_bit(R5_Wantread, &dev->flags); s->locked++; } else { set_bit(STRIPE_DELAYED, &sh->state); set_bit(STRIPE_HANDLE, &sh->state); } } } if (rcw <= rmw && rcw > 0) /* want reconstruct write, but need to get some data */ for (i = disks; i--; ) { struct r5dev *dev = &sh->dev[i]; if (!test_bit(R5_OVERWRITE, &dev->flags) && i != sh->pd_idx && !test_bit(R5_LOCKED, &dev->flags) && !(test_bit(R5_UPTODATE, &dev->flags) || test_bit(R5_Wantcompute, &dev->flags)) && test_bit(R5_Insync, &dev->flags)) { if ( test_bit(STRIPE_PREREAD_ACTIVE, &sh->state)) { pr_debug("Read_old block " "%d for Reconstruct\n", i); set_bit(R5_LOCKED, &dev->flags); set_bit(R5_Wantread, &dev->flags); s->locked++; } else { set_bit(STRIPE_DELAYED, &sh->state); set_bit(STRIPE_HANDLE, &sh->state); } } } /* now if nothing is locked, and if we have enough data, * we can start a write request */ /* since handle_stripe can be called at any time we need to handle the * case where a compute block operation has been submitted and then a * subsequent call wants to start a write request. raid5_run_ops only * handles the case where compute block and postxor are requested * simultaneously. If this is not the case then new writes need to be * held off until the compute completes. */ if ((s->req_compute || !test_bit(STRIPE_COMPUTE_RUN, &sh->state)) && (s->locked == 0 && (rcw == 0 || rmw == 0) && !test_bit(STRIPE_BIT_DELAY, &sh->state))) schedule_reconstruction5(sh, s, rcw == 0, 0); } static void handle_stripe_dirtying6(raid5_conf_t *conf, struct stripe_head *sh, struct stripe_head_state *s, struct r6_state *r6s, int disks) { int rcw = 0, must_compute = 0, pd_idx = sh->pd_idx, i; int qd_idx = sh->qd_idx; for (i = disks; i--; ) { struct r5dev *dev = &sh->dev[i]; /* Would I have to read this buffer for reconstruct_write */ if (!test_bit(R5_OVERWRITE, &dev->flags) && i != pd_idx && i != qd_idx && (!test_bit(R5_LOCKED, &dev->flags) ) && !test_bit(R5_UPTODATE, &dev->flags)) { if (test_bit(R5_Insync, &dev->flags)) rcw++; else { pr_debug("raid6: must_compute: " "disk %d flags=%#lx\n", i, dev->flags); must_compute++; } } } pr_debug("for sector %llu, rcw=%d, must_compute=%d\n", (unsigned long long)sh->sector, rcw, must_compute); set_bit(STRIPE_HANDLE, &sh->state); if (rcw > 0) /* want reconstruct write, but need to get some data */ for (i = disks; i--; ) { struct r5dev *dev = &sh->dev[i]; if (!test_bit(R5_OVERWRITE, &dev->flags) && !(s->failed == 0 && (i == pd_idx || i == qd_idx)) && !test_bit(R5_LOCKED, &dev->flags) && !test_bit(R5_UPTODATE, &dev->flags) && test_bit(R5_Insync, &dev->flags)) { if ( test_bit(STRIPE_PREREAD_ACTIVE, &sh->state)) { pr_debug("Read_old stripe %llu " "block %d for Reconstruct\n", (unsigned long long)sh->sector, i); set_bit(R5_LOCKED, &dev->flags); set_bit(R5_Wantread, &dev->flags); s->locked++; } else { pr_debug("Request delayed stripe %llu " "block %d for Reconstruct\n", (unsigned long long)sh->sector, i); set_bit(STRIPE_DELAYED, &sh->state); set_bit(STRIPE_HANDLE, &sh->state); } } } /* now if nothing is locked, and if we have enough data, we can start a * write request */ if (s->locked == 0 && rcw == 0 && !test_bit(STRIPE_BIT_DELAY, &sh->state)) { if (must_compute > 0) { /* We have failed blocks and need to compute them */ switch (s->failed) { case 0: BUG(); case 1: compute_block_1(sh, r6s->failed_num[0], 0); break; case 2: compute_block_2(sh, r6s->failed_num[0], r6s->failed_num[1]); break; default: /* This request should have been failed? */ BUG(); } } pr_debug("Computing parity for stripe %llu\n", (unsigned long long)sh->sector); compute_parity6(sh, RECONSTRUCT_WRITE); /* now every locked buffer is ready to be written */ for (i = disks; i--; ) if (test_bit(R5_LOCKED, &sh->dev[i].flags)) { pr_debug("Writing stripe %llu block %d\n", (unsigned long long)sh->sector, i); s->locked++; set_bit(R5_Wantwrite, &sh->dev[i].flags); } if (s->locked == disks) if (!test_and_set_bit(STRIPE_FULL_WRITE, &sh->state)) atomic_inc(&conf->pending_full_writes); /* after a RECONSTRUCT_WRITE, the stripe MUST be in-sync */ set_bit(STRIPE_INSYNC, &sh->state); if (test_and_clear_bit(STRIPE_PREREAD_ACTIVE, &sh->state)) { atomic_dec(&conf->preread_active_stripes); if (atomic_read(&conf->preread_active_stripes) < IO_THRESHOLD) md_wakeup_thread(conf->mddev->thread); } } } static void handle_parity_checks5(raid5_conf_t *conf, struct stripe_head *sh, struct stripe_head_state *s, int disks) { struct r5dev *dev = NULL; set_bit(STRIPE_HANDLE, &sh->state); switch (sh->check_state) { case check_state_idle: /* start a new check operation if there are no failures */ if (s->failed == 0) { BUG_ON(s->uptodate != disks); sh->check_state = check_state_run; set_bit(STRIPE_OP_CHECK, &s->ops_request); clear_bit(R5_UPTODATE, &sh->dev[sh->pd_idx].flags); s->uptodate--; break; } dev = &sh->dev[s->failed_num]; /* fall through */ case check_state_compute_result: sh->check_state = check_state_idle; if (!dev) dev = &sh->dev[sh->pd_idx]; /* check that a write has not made the stripe insync */ if (test_bit(STRIPE_INSYNC, &sh->state)) break; /* either failed parity check, or recovery is happening */ BUG_ON(!test_bit(R5_UPTODATE, &dev->flags)); BUG_ON(s->uptodate != disks); set_bit(R5_LOCKED, &dev->flags); s->locked++; set_bit(R5_Wantwrite, &dev->flags); clear_bit(STRIPE_DEGRADED, &sh->state); set_bit(STRIPE_INSYNC, &sh->state); break; case check_state_run: break; /* we will be called again upon completion */ case check_state_check_result: sh->check_state = check_state_idle; /* if a failure occurred during the check operation, leave * STRIPE_INSYNC not set and let the stripe be handled again */ if (s->failed) break; /* handle a successful check operation, if parity is correct * we are done. Otherwise update the mismatch count and repair * parity if !MD_RECOVERY_CHECK */ if (sh->ops.zero_sum_result == 0) /* parity is correct (on disc, * not in buffer any more) */ set_bit(STRIPE_INSYNC, &sh->state); else { conf->mddev->resync_mismatches += STRIPE_SECTORS; if (test_bit(MD_RECOVERY_CHECK, &conf->mddev->recovery)) /* don't try to repair!! */ set_bit(STRIPE_INSYNC, &sh->state); else { sh->check_state = check_state_compute_run; set_bit(STRIPE_COMPUTE_RUN, &sh->state); set_bit(STRIPE_OP_COMPUTE_BLK, &s->ops_request); set_bit(R5_Wantcompute, &sh->dev[sh->pd_idx].flags); sh->ops.target = sh->pd_idx; s->uptodate++; } } break; case check_state_compute_run: break; default: printk(KERN_ERR "%s: unknown check_state: %d sector: %llu\n", __func__, sh->check_state, (unsigned long long) sh->sector); BUG(); } } static void handle_parity_checks6(raid5_conf_t *conf, struct stripe_head *sh, struct stripe_head_state *s, struct r6_state *r6s, struct page *tmp_page, int disks) { int update_p = 0, update_q = 0; struct r5dev *dev; int pd_idx = sh->pd_idx; int qd_idx = sh->qd_idx; set_bit(STRIPE_HANDLE, &sh->state); BUG_ON(s->failed > 2); BUG_ON(s->uptodate < disks); /* Want to check and possibly repair P and Q. * However there could be one 'failed' device, in which * case we can only check one of them, possibly using the * other to generate missing data */ /* If !tmp_page, we cannot do the calculations, * but as we have set STRIPE_HANDLE, we will soon be called * by stripe_handle with a tmp_page - just wait until then. */ if (tmp_page) { if (s->failed == r6s->q_failed) { /* The only possible failed device holds 'Q', so it * makes sense to check P (If anything else were failed, * we would have used P to recreate it). */ compute_block_1(sh, pd_idx, 1); if (!page_is_zero(sh->dev[pd_idx].page)) { compute_block_1(sh, pd_idx, 0); update_p = 1; } } if (!r6s->q_failed && s->failed < 2) { /* q is not failed, and we didn't use it to generate * anything, so it makes sense to check it */ memcpy(page_address(tmp_page), page_address(sh->dev[qd_idx].page), STRIPE_SIZE); compute_parity6(sh, UPDATE_PARITY); if (memcmp(page_address(tmp_page), page_address(sh->dev[qd_idx].page), STRIPE_SIZE) != 0) { clear_bit(STRIPE_INSYNC, &sh->state); update_q = 1; } } if (update_p || update_q) { conf->mddev->resync_mismatches += STRIPE_SECTORS; if (test_bit(MD_RECOVERY_CHECK, &conf->mddev->recovery)) /* don't try to repair!! */ update_p = update_q = 0; } /* now write out any block on a failed drive, * or P or Q if they need it */ if (s->failed == 2) { dev = &sh->dev[r6s->failed_num[1]]; s->locked++; set_bit(R5_LOCKED, &dev->flags); set_bit(R5_Wantwrite, &dev->flags); } if (s->failed >= 1) { dev = &sh->dev[r6s->failed_num[0]]; s->locked++; set_bit(R5_LOCKED, &dev->flags); set_bit(R5_Wantwrite, &dev->flags); } if (update_p) { dev = &sh->dev[pd_idx]; s->locked++; set_bit(R5_LOCKED, &dev->flags); set_bit(R5_Wantwrite, &dev->flags); } if (update_q) { dev = &sh->dev[qd_idx]; s->locked++; set_bit(R5_LOCKED, &dev->flags); set_bit(R5_Wantwrite, &dev->flags); } clear_bit(STRIPE_DEGRADED, &sh->state); set_bit(STRIPE_INSYNC, &sh->state); } } static void handle_stripe_expansion(raid5_conf_t *conf, struct stripe_head *sh, struct r6_state *r6s) { int i; /* We have read all the blocks in this stripe and now we need to * copy some of them into a target stripe for expand. */ struct dma_async_tx_descriptor *tx = NULL; clear_bit(STRIPE_EXPAND_SOURCE, &sh->state); for (i = 0; i < sh->disks; i++) if (i != sh->pd_idx && i != sh->qd_idx) { int dd_idx, j; struct stripe_head *sh2; sector_t bn = compute_blocknr(sh, i, 1); sector_t s = raid5_compute_sector(conf, bn, 0, &dd_idx, NULL); sh2 = get_active_stripe(conf, s, 0, 1); if (sh2 == NULL) /* so far only the early blocks of this stripe * have been requested. When later blocks * get requested, we will try again */ continue; if (!test_bit(STRIPE_EXPANDING, &sh2->state) || test_bit(R5_Expanded, &sh2->dev[dd_idx].flags)) { /* must have already done this block */ release_stripe(sh2); continue; } /* place all the copies on one channel */ tx = async_memcpy(sh2->dev[dd_idx].page, sh->dev[i].page, 0, 0, STRIPE_SIZE, ASYNC_TX_DEP_ACK, tx, NULL, NULL); set_bit(R5_Expanded, &sh2->dev[dd_idx].flags); set_bit(R5_UPTODATE, &sh2->dev[dd_idx].flags); for (j = 0; j < conf->raid_disks; j++) if (j != sh2->pd_idx && (!r6s || j != sh2->qd_idx) && !test_bit(R5_Expanded, &sh2->dev[j].flags)) break; if (j == conf->raid_disks) { set_bit(STRIPE_EXPAND_READY, &sh2->state); set_bit(STRIPE_HANDLE, &sh2->state); } release_stripe(sh2); } /* done submitting copies, wait for them to complete */ if (tx) { async_tx_ack(tx); dma_wait_for_async_tx(tx); } } /* * handle_stripe - do things to a stripe. * * We lock the stripe and then examine the state of various bits * to see what needs to be done. * Possible results: * return some read request which now have data * return some write requests which are safely on disc * schedule a read on some buffers * schedule a write of some buffers * return confirmation of parity correctness * * buffers are taken off read_list or write_list, and bh_cache buffers * get BH_Lock set before the stripe lock is released. * */ static bool handle_stripe5(struct stripe_head *sh) { raid5_conf_t *conf = sh->raid_conf; int disks = sh->disks, i; struct bio *return_bi = NULL; struct stripe_head_state s; struct r5dev *dev; mdk_rdev_t *blocked_rdev = NULL; int prexor; memset(&s, 0, sizeof(s)); pr_debug("handling stripe %llu, state=%#lx cnt=%d, pd_idx=%d check:%d " "reconstruct:%d\n", (unsigned long long)sh->sector, sh->state, atomic_read(&sh->count), sh->pd_idx, sh->check_state, sh->reconstruct_state); spin_lock(&sh->lock); clear_bit(STRIPE_HANDLE, &sh->state); clear_bit(STRIPE_DELAYED, &sh->state); s.syncing = test_bit(STRIPE_SYNCING, &sh->state); s.expanding = test_bit(STRIPE_EXPAND_SOURCE, &sh->state); s.expanded = test_bit(STRIPE_EXPAND_READY, &sh->state); /* Now to look around and see what can be done */ rcu_read_lock(); for (i=disks; i--; ) { mdk_rdev_t *rdev; struct r5dev *dev = &sh->dev[i]; clear_bit(R5_Insync, &dev->flags); pr_debug("check %d: state 0x%lx toread %p read %p write %p " "written %p\n", i, dev->flags, dev->toread, dev->read, dev->towrite, dev->written); /* maybe we can request a biofill operation * * new wantfill requests are only permitted while * ops_complete_biofill is guaranteed to be inactive */ if (test_bit(R5_UPTODATE, &dev->flags) && dev->toread && !test_bit(STRIPE_BIOFILL_RUN, &sh->state)) set_bit(R5_Wantfill, &dev->flags); /* now count some things */ if (test_bit(R5_LOCKED, &dev->flags)) s.locked++; if (test_bit(R5_UPTODATE, &dev->flags)) s.uptodate++; if (test_bit(R5_Wantcompute, &dev->flags)) s.compute++; if (test_bit(R5_Wantfill, &dev->flags)) s.to_fill++; else if (dev->toread) s.to_read++; if (dev->towrite) { s.to_write++; if (!test_bit(R5_OVERWRITE, &dev->flags)) s.non_overwrite++; } if (dev->written) s.written++; rdev = rcu_dereference(conf->disks[i].rdev); if (blocked_rdev == NULL && rdev && unlikely(test_bit(Blocked, &rdev->flags))) { blocked_rdev = rdev; atomic_inc(&rdev->nr_pending); } if (!rdev || !test_bit(In_sync, &rdev->flags)) { /* The ReadError flag will just be confusing now */ clear_bit(R5_ReadError, &dev->flags); clear_bit(R5_ReWrite, &dev->flags); } if (!rdev || !test_bit(In_sync, &rdev->flags) || test_bit(R5_ReadError, &dev->flags)) { s.failed++; s.failed_num = i; } else set_bit(R5_Insync, &dev->flags); } rcu_read_unlock(); if (unlikely(blocked_rdev)) { if (s.syncing || s.expanding || s.expanded || s.to_write || s.written) { set_bit(STRIPE_HANDLE, &sh->state); goto unlock; } /* There is nothing for the blocked_rdev to block */ rdev_dec_pending(blocked_rdev, conf->mddev); blocked_rdev = NULL; } if (s.to_fill && !test_bit(STRIPE_BIOFILL_RUN, &sh->state)) { set_bit(STRIPE_OP_BIOFILL, &s.ops_request); set_bit(STRIPE_BIOFILL_RUN, &sh->state); } pr_debug("locked=%d uptodate=%d to_read=%d" " to_write=%d failed=%d failed_num=%d\n", s.locked, s.uptodate, s.to_read, s.to_write, s.failed, s.failed_num); /* check if the array has lost two devices and, if so, some requests might * need to be failed */ if (s.failed > 1 && s.to_read+s.to_write+s.written) handle_failed_stripe(conf, sh, &s, disks, &return_bi); if (s.failed > 1 && s.syncing) { md_done_sync(conf->mddev, STRIPE_SECTORS,0); clear_bit(STRIPE_SYNCING, &sh->state); s.syncing = 0; } /* might be able to return some write requests if the parity block * is safe, or on a failed drive */ dev = &sh->dev[sh->pd_idx]; if ( s.written && ((test_bit(R5_Insync, &dev->flags) && !test_bit(R5_LOCKED, &dev->flags) && test_bit(R5_UPTODATE, &dev->flags)) || (s.failed == 1 && s.failed_num == sh->pd_idx))) handle_stripe_clean_event(conf, sh, disks, &return_bi); /* Now we might consider reading some blocks, either to check/generate * parity, or to satisfy requests * or to load a block that is being partially written. */ if (s.to_read || s.non_overwrite || (s.syncing && (s.uptodate + s.compute < disks)) || s.expanding) handle_stripe_fill5(sh, &s, disks); /* Now we check to see if any write operations have recently * completed */ prexor = 0; if (sh->reconstruct_state == reconstruct_state_prexor_drain_result) prexor = 1; if (sh->reconstruct_state == reconstruct_state_drain_result || sh->reconstruct_state == reconstruct_state_prexor_drain_result) { sh->reconstruct_state = reconstruct_state_idle; /* All the 'written' buffers and the parity block are ready to * be written back to disk */ BUG_ON(!test_bit(R5_UPTODATE, &sh->dev[sh->pd_idx].flags)); for (i = disks; i--; ) { dev = &sh->dev[i]; if (test_bit(R5_LOCKED, &dev->flags) && (i == sh->pd_idx || dev->written)) { pr_debug("Writing block %d\n", i); set_bit(R5_Wantwrite, &dev->flags); if (prexor) continue; if (!test_bit(R5_Insync, &dev->flags) || (i == sh->pd_idx && s.failed == 0)) set_bit(STRIPE_INSYNC, &sh->state); } } if (test_and_clear_bit(STRIPE_PREREAD_ACTIVE, &sh->state)) { atomic_dec(&conf->preread_active_stripes); if (atomic_read(&conf->preread_active_stripes) < IO_THRESHOLD) md_wakeup_thread(conf->mddev->thread); } } /* Now to consider new write requests and what else, if anything * should be read. We do not handle new writes when: * 1/ A 'write' operation (copy+xor) is already in flight. * 2/ A 'check' operation is in flight, as it may clobber the parity * block. */ if (s.to_write && !sh->reconstruct_state && !sh->check_state) handle_stripe_dirtying5(conf, sh, &s, disks); /* maybe we need to check and possibly fix the parity for this stripe * Any reads will already have been scheduled, so we just see if enough * data is available. The parity check is held off while parity * dependent operations are in flight. */ if (sh->check_state || (s.syncing && s.locked == 0 && !test_bit(STRIPE_COMPUTE_RUN, &sh->state) && !test_bit(STRIPE_INSYNC, &sh->state))) handle_parity_checks5(conf, sh, &s, disks); if (s.syncing && s.locked == 0 && test_bit(STRIPE_INSYNC, &sh->state)) { md_done_sync(conf->mddev, STRIPE_SECTORS,1); clear_bit(STRIPE_SYNCING, &sh->state); } /* If the failed drive is just a ReadError, then we might need to progress * the repair/check process */ if (s.failed == 1 && !conf->mddev->ro && test_bit(R5_ReadError, &sh->dev[s.failed_num].flags) && !test_bit(R5_LOCKED, &sh->dev[s.failed_num].flags) && test_bit(R5_UPTODATE, &sh->dev[s.failed_num].flags) ) { dev = &sh->dev[s.failed_num]; if (!test_bit(R5_ReWrite, &dev->flags)) { set_bit(R5_Wantwrite, &dev->flags); set_bit(R5_ReWrite, &dev->flags); set_bit(R5_LOCKED, &dev->flags); s.locked++; } else { /* let's read it back */ set_bit(R5_Wantread, &dev->flags); set_bit(R5_LOCKED, &dev->flags); s.locked++; } } /* Finish reconstruct operations initiated by the expansion process */ if (sh->reconstruct_state == reconstruct_state_result) { struct stripe_head *sh2 = get_active_stripe(conf, sh->sector, 1, 1); if (sh2 && test_bit(STRIPE_EXPAND_SOURCE, &sh2->state)) { /* sh cannot be written until sh2 has been read. * so arrange for sh to be delayed a little */ set_bit(STRIPE_DELAYED, &sh->state); set_bit(STRIPE_HANDLE, &sh->state); if (!test_and_set_bit(STRIPE_PREREAD_ACTIVE, &sh2->state)) atomic_inc(&conf->preread_active_stripes); release_stripe(sh2); goto unlock; } if (sh2) release_stripe(sh2); sh->reconstruct_state = reconstruct_state_idle; clear_bit(STRIPE_EXPANDING, &sh->state); for (i = conf->raid_disks; i--; ) { set_bit(R5_Wantwrite, &sh->dev[i].flags); set_bit(R5_LOCKED, &sh->dev[i].flags); s.locked++; } } if (s.expanded && test_bit(STRIPE_EXPANDING, &sh->state) && !sh->reconstruct_state) { /* Need to write out all blocks after computing parity */ sh->disks = conf->raid_disks; stripe_set_idx(sh->sector, conf, 0, sh); schedule_reconstruction5(sh, &s, 1, 1); } else if (s.expanded && !sh->reconstruct_state && s.locked == 0) { clear_bit(STRIPE_EXPAND_READY, &sh->state); atomic_dec(&conf->reshape_stripes); wake_up(&conf->wait_for_overlap); md_done_sync(conf->mddev, STRIPE_SECTORS, 1); } if (s.expanding && s.locked == 0 && !test_bit(STRIPE_COMPUTE_RUN, &sh->state)) handle_stripe_expansion(conf, sh, NULL); unlock: spin_unlock(&sh->lock); /* wait for this device to become unblocked */ if (unlikely(blocked_rdev)) md_wait_for_blocked_rdev(blocked_rdev, conf->mddev); if (s.ops_request) raid5_run_ops(sh, s.ops_request); ops_run_io(sh, &s); return_io(return_bi); return blocked_rdev == NULL; } static bool handle_stripe6(struct stripe_head *sh, struct page *tmp_page) { raid5_conf_t *conf = sh->raid_conf; int disks = sh->disks; struct bio *return_bi = NULL; int i, pd_idx = sh->pd_idx, qd_idx = sh->qd_idx; struct stripe_head_state s; struct r6_state r6s; struct r5dev *dev, *pdev, *qdev; mdk_rdev_t *blocked_rdev = NULL; pr_debug("handling stripe %llu, state=%#lx cnt=%d, " "pd_idx=%d, qd_idx=%d\n", (unsigned long long)sh->sector, sh->state, atomic_read(&sh->count), pd_idx, qd_idx); memset(&s, 0, sizeof(s)); spin_lock(&sh->lock); clear_bit(STRIPE_HANDLE, &sh->state); clear_bit(STRIPE_DELAYED, &sh->state); s.syncing = test_bit(STRIPE_SYNCING, &sh->state); s.expanding = test_bit(STRIPE_EXPAND_SOURCE, &sh->state); s.expanded = test_bit(STRIPE_EXPAND_READY, &sh->state); /* Now to look around and see what can be done */ rcu_read_lock(); for (i=disks; i--; ) { mdk_rdev_t *rdev; dev = &sh->dev[i]; clear_bit(R5_Insync, &dev->flags); pr_debug("check %d: state 0x%lx read %p write %p written %p\n", i, dev->flags, dev->toread, dev->towrite, dev->written); /* maybe we can reply to a read */ if (test_bit(R5_UPTODATE, &dev->flags) && dev->toread) { struct bio *rbi, *rbi2; pr_debug("Return read for disc %d\n", i); spin_lock_irq(&conf->device_lock); rbi = dev->toread; dev->toread = NULL; if (test_and_clear_bit(R5_Overlap, &dev->flags)) wake_up(&conf->wait_for_overlap); spin_unlock_irq(&conf->device_lock); while (rbi && rbi->bi_sector < dev->sector + STRIPE_SECTORS) { copy_data(0, rbi, dev->page, dev->sector); rbi2 = r5_next_bio(rbi, dev->sector); spin_lock_irq(&conf->device_lock); if (!raid5_dec_bi_phys_segments(rbi)) { rbi->bi_next = return_bi; return_bi = rbi; } spin_unlock_irq(&conf->device_lock); rbi = rbi2; } } /* now count some things */ if (test_bit(R5_LOCKED, &dev->flags)) s.locked++; if (test_bit(R5_UPTODATE, &dev->flags)) s.uptodate++; if (dev->toread) s.to_read++; if (dev->towrite) { s.to_write++; if (!test_bit(R5_OVERWRITE, &dev->flags)) s.non_overwrite++; } if (dev->written) s.written++; rdev = rcu_dereference(conf->disks[i].rdev); if (blocked_rdev == NULL && rdev && unlikely(test_bit(Blocked, &rdev->flags))) { blocked_rdev = rdev; atomic_inc(&rdev->nr_pending); } if (!rdev || !test_bit(In_sync, &rdev->flags)) { /* The ReadError flag will just be confusing now */ clear_bit(R5_ReadError, &dev->flags); clear_bit(R5_ReWrite, &dev->flags); } if (!rdev || !test_bit(In_sync, &rdev->flags) || test_bit(R5_ReadError, &dev->flags)) { if (s.failed < 2) r6s.failed_num[s.failed] = i; s.failed++; } else set_bit(R5_Insync, &dev->flags); } rcu_read_unlock(); if (unlikely(blocked_rdev)) { if (s.syncing || s.expanding || s.expanded || s.to_write || s.written) { set_bit(STRIPE_HANDLE, &sh->state); goto unlock; } /* There is nothing for the blocked_rdev to block */ rdev_dec_pending(blocked_rdev, conf->mddev); blocked_rdev = NULL; } pr_debug("locked=%d uptodate=%d to_read=%d" " to_write=%d failed=%d failed_num=%d,%d\n", s.locked, s.uptodate, s.to_read, s.to_write, s.failed, r6s.failed_num[0], r6s.failed_num[1]); /* check if the array has lost >2 devices and, if so, some requests * might need to be failed */ if (s.failed > 2 && s.to_read+s.to_write+s.written) handle_failed_stripe(conf, sh, &s, disks, &return_bi); if (s.failed > 2 && s.syncing) { md_done_sync(conf->mddev, STRIPE_SECTORS,0); clear_bit(STRIPE_SYNCING, &sh->state); s.syncing = 0; } /* * might be able to return some write requests if the parity blocks * are safe, or on a failed drive */ pdev = &sh->dev[pd_idx]; r6s.p_failed = (s.failed >= 1 && r6s.failed_num[0] == pd_idx) || (s.failed >= 2 && r6s.failed_num[1] == pd_idx); qdev = &sh->dev[qd_idx]; r6s.q_failed = (s.failed >= 1 && r6s.failed_num[0] == qd_idx) || (s.failed >= 2 && r6s.failed_num[1] == qd_idx); if ( s.written && ( r6s.p_failed || ((test_bit(R5_Insync, &pdev->flags) && !test_bit(R5_LOCKED, &pdev->flags) && test_bit(R5_UPTODATE, &pdev->flags)))) && ( r6s.q_failed || ((test_bit(R5_Insync, &qdev->flags) && !test_bit(R5_LOCKED, &qdev->flags) && test_bit(R5_UPTODATE, &qdev->flags))))) handle_stripe_clean_event(conf, sh, disks, &return_bi); /* Now we might consider reading some blocks, either to check/generate * parity, or to satisfy requests * or to load a block that is being partially written. */ if (s.to_read || s.non_overwrite || (s.to_write && s.failed) || (s.syncing && (s.uptodate < disks)) || s.expanding) handle_stripe_fill6(sh, &s, &r6s, disks); /* now to consider writing and what else, if anything should be read */ if (s.to_write) handle_stripe_dirtying6(conf, sh, &s, &r6s, disks); /* maybe we need to check and possibly fix the parity for this stripe * Any reads will already have been scheduled, so we just see if enough * data is available */ if (s.syncing && s.locked == 0 && !test_bit(STRIPE_INSYNC, &sh->state)) handle_parity_checks6(conf, sh, &s, &r6s, tmp_page, disks); if (s.syncing && s.locked == 0 && test_bit(STRIPE_INSYNC, &sh->state)) { md_done_sync(conf->mddev, STRIPE_SECTORS,1); clear_bit(STRIPE_SYNCING, &sh->state); } /* If the failed drives are just a ReadError, then we might need * to progress the repair/check process */ if (s.failed <= 2 && !conf->mddev->ro) for (i = 0; i < s.failed; i++) { dev = &sh->dev[r6s.failed_num[i]]; if (test_bit(R5_ReadError, &dev->flags) && !test_bit(R5_LOCKED, &dev->flags) && test_bit(R5_UPTODATE, &dev->flags) ) { if (!test_bit(R5_ReWrite, &dev->flags)) { set_bit(R5_Wantwrite, &dev->flags); set_bit(R5_ReWrite, &dev->flags); set_bit(R5_LOCKED, &dev->flags); } else { /* let's read it back */ set_bit(R5_Wantread, &dev->flags); set_bit(R5_LOCKED, &dev->flags); } } } if (s.expanded && test_bit(STRIPE_EXPANDING, &sh->state)) { struct stripe_head *sh2 = get_active_stripe(conf, sh->sector, 1, 1); if (sh2 && test_bit(STRIPE_EXPAND_SOURCE, &sh2->state)) { /* sh cannot be written until sh2 has been read. * so arrange for sh to be delayed a little */ set_bit(STRIPE_DELAYED, &sh->state); set_bit(STRIPE_HANDLE, &sh->state); if (!test_and_set_bit(STRIPE_PREREAD_ACTIVE, &sh2->state)) atomic_inc(&conf->preread_active_stripes); release_stripe(sh2); goto unlock; } if (sh2) release_stripe(sh2); /* Need to write out all blocks after computing P&Q */ sh->disks = conf->raid_disks; stripe_set_idx(sh->sector, conf, 0, sh); compute_parity6(sh, RECONSTRUCT_WRITE); for (i = conf->raid_disks ; i-- ; ) { set_bit(R5_LOCKED, &sh->dev[i].flags); s.locked++; set_bit(R5_Wantwrite, &sh->dev[i].flags); } clear_bit(STRIPE_EXPANDING, &sh->state); } else if (s.expanded) { clear_bit(STRIPE_EXPAND_READY, &sh->state); atomic_dec(&conf->reshape_stripes); wake_up(&conf->wait_for_overlap); md_done_sync(conf->mddev, STRIPE_SECTORS, 1); } if (s.expanding && s.locked == 0 && !test_bit(STRIPE_COMPUTE_RUN, &sh->state)) handle_stripe_expansion(conf, sh, &r6s); unlock: spin_unlock(&sh->lock); /* wait for this device to become unblocked */ if (unlikely(blocked_rdev)) md_wait_for_blocked_rdev(blocked_rdev, conf->mddev); ops_run_io(sh, &s); return_io(return_bi); return blocked_rdev == NULL; } /* returns true if the stripe was handled */ static bool handle_stripe(struct stripe_head *sh, struct page *tmp_page) { if (sh->raid_conf->level == 6) return handle_stripe6(sh, tmp_page); else return handle_stripe5(sh); } static void raid5_activate_delayed(raid5_conf_t *conf) { if (atomic_read(&conf->preread_active_stripes) < IO_THRESHOLD) { while (!list_empty(&conf->delayed_list)) { struct list_head *l = conf->delayed_list.next; struct stripe_head *sh; sh = list_entry(l, struct stripe_head, lru); list_del_init(l); clear_bit(STRIPE_DELAYED, &sh->state); if (!test_and_set_bit(STRIPE_PREREAD_ACTIVE, &sh->state)) atomic_inc(&conf->preread_active_stripes); list_add_tail(&sh->lru, &conf->hold_list); } } else blk_plug_device(conf->mddev->queue); } static void activate_bit_delay(raid5_conf_t *conf) { /* device_lock is held */ struct list_head head; list_add(&head, &conf->bitmap_list); list_del_init(&conf->bitmap_list); while (!list_empty(&head)) { struct stripe_head *sh = list_entry(head.next, struct stripe_head, lru); list_del_init(&sh->lru); atomic_inc(&sh->count); __release_stripe(conf, sh); } } static void unplug_slaves(mddev_t *mddev) { raid5_conf_t *conf = mddev_to_conf(mddev); int i; rcu_read_lock(); for (i=0; iraid_disks; i++) { mdk_rdev_t *rdev = rcu_dereference(conf->disks[i].rdev); if (rdev && !test_bit(Faulty, &rdev->flags) && atomic_read(&rdev->nr_pending)) { struct request_queue *r_queue = bdev_get_queue(rdev->bdev); atomic_inc(&rdev->nr_pending); rcu_read_unlock(); blk_unplug(r_queue); rdev_dec_pending(rdev, mddev); rcu_read_lock(); } } rcu_read_unlock(); } static void raid5_unplug_device(struct request_queue *q) { mddev_t *mddev = q->queuedata; raid5_conf_t *conf = mddev_to_conf(mddev); unsigned long flags; spin_lock_irqsave(&conf->device_lock, flags); if (blk_remove_plug(q)) { conf->seq_flush++; raid5_activate_delayed(conf); } md_wakeup_thread(mddev->thread); spin_unlock_irqrestore(&conf->device_lock, flags); unplug_slaves(mddev); } static int raid5_congested(void *data, int bits) { mddev_t *mddev = data; raid5_conf_t *conf = mddev_to_conf(mddev); /* No difference between reads and writes. Just check * how busy the stripe_cache is */ if (conf->inactive_blocked) return 1; if (conf->quiesce) return 1; if (list_empty_careful(&conf->inactive_list)) return 1; return 0; } /* We want read requests to align with chunks where possible, * but write requests don't need to. */ static int raid5_mergeable_bvec(struct request_queue *q, struct bvec_merge_data *bvm, struct bio_vec *biovec) { mddev_t *mddev = q->queuedata; sector_t sector = bvm->bi_sector + get_start_sect(bvm->bi_bdev); int max; unsigned int chunk_sectors = mddev->chunk_size >> 9; unsigned int bio_sectors = bvm->bi_size >> 9; if ((bvm->bi_rw & 1) == WRITE) return biovec->bv_len; /* always allow writes to be mergeable */ if (mddev->new_chunk < mddev->chunk_size) chunk_sectors = mddev->new_chunk >> 9; max = (chunk_sectors - ((sector & (chunk_sectors - 1)) + bio_sectors)) << 9; if (max < 0) max = 0; if (max <= biovec->bv_len && bio_sectors == 0) return biovec->bv_len; else return max; } static int in_chunk_boundary(mddev_t *mddev, struct bio *bio) { sector_t sector = bio->bi_sector + get_start_sect(bio->bi_bdev); unsigned int chunk_sectors = mddev->chunk_size >> 9; unsigned int bio_sectors = bio->bi_size >> 9; if (mddev->new_chunk < mddev->chunk_size) chunk_sectors = mddev->new_chunk >> 9; return chunk_sectors >= ((sector & (chunk_sectors - 1)) + bio_sectors); } /* * add bio to the retry LIFO ( in O(1) ... we are in interrupt ) * later sampled by raid5d. */ static void add_bio_to_retry(struct bio *bi,raid5_conf_t *conf) { unsigned long flags; spin_lock_irqsave(&conf->device_lock, flags); bi->bi_next = conf->retry_read_aligned_list; conf->retry_read_aligned_list = bi; spin_unlock_irqrestore(&conf->device_lock, flags); md_wakeup_thread(conf->mddev->thread); } static struct bio *remove_bio_from_retry(raid5_conf_t *conf) { struct bio *bi; bi = conf->retry_read_aligned; if (bi) { conf->retry_read_aligned = NULL; return bi; } bi = conf->retry_read_aligned_list; if(bi) { conf->retry_read_aligned_list = bi->bi_next; bi->bi_next = NULL; /* * this sets the active strip count to 1 and the processed * strip count to zero (upper 8 bits) */ bi->bi_phys_segments = 1; /* biased count of active stripes */ } return bi; } /* * The "raid5_align_endio" should check if the read succeeded and if it * did, call bio_endio on the original bio (having bio_put the new bio * first). * If the read failed.. */ static void raid5_align_endio(struct bio *bi, int error) { struct bio* raid_bi = bi->bi_private; mddev_t *mddev; raid5_conf_t *conf; int uptodate = test_bit(BIO_UPTODATE, &bi->bi_flags); mdk_rdev_t *rdev; bio_put(bi); mddev = raid_bi->bi_bdev->bd_disk->queue->queuedata; conf = mddev_to_conf(mddev); rdev = (void*)raid_bi->bi_next; raid_bi->bi_next = NULL; rdev_dec_pending(rdev, conf->mddev); if (!error && uptodate) { bio_endio(raid_bi, 0); if (atomic_dec_and_test(&conf->active_aligned_reads)) wake_up(&conf->wait_for_stripe); return; } pr_debug("raid5_align_endio : io error...handing IO for a retry\n"); add_bio_to_retry(raid_bi, conf); } static int bio_fits_rdev(struct bio *bi) { struct request_queue *q = bdev_get_queue(bi->bi_bdev); if ((bi->bi_size>>9) > q->max_sectors) return 0; blk_recount_segments(q, bi); if (bi->bi_phys_segments > q->max_phys_segments) return 0; if (q->merge_bvec_fn) /* it's too hard to apply the merge_bvec_fn at this stage, * just just give up */ return 0; return 1; } static int chunk_aligned_read(struct request_queue *q, struct bio * raid_bio) { mddev_t *mddev = q->queuedata; raid5_conf_t *conf = mddev_to_conf(mddev); unsigned int dd_idx; struct bio* align_bi; mdk_rdev_t *rdev; if (!in_chunk_boundary(mddev, raid_bio)) { pr_debug("chunk_aligned_read : non aligned\n"); return 0; } /* * use bio_clone to make a copy of the bio */ align_bi = bio_clone(raid_bio, GFP_NOIO); if (!align_bi) return 0; /* * set bi_end_io to a new function, and set bi_private to the * original bio. */ align_bi->bi_end_io = raid5_align_endio; align_bi->bi_private = raid_bio; /* * compute position */ align_bi->bi_sector = raid5_compute_sector(conf, raid_bio->bi_sector, 0, &dd_idx, NULL); rcu_read_lock(); rdev = rcu_dereference(conf->disks[dd_idx].rdev); if (rdev && test_bit(In_sync, &rdev->flags)) { atomic_inc(&rdev->nr_pending); rcu_read_unlock(); raid_bio->bi_next = (void*)rdev; align_bi->bi_bdev = rdev->bdev; align_bi->bi_flags &= ~(1 << BIO_SEG_VALID); align_bi->bi_sector += rdev->data_offset; if (!bio_fits_rdev(align_bi)) { /* too big in some way */ bio_put(align_bi); rdev_dec_pending(rdev, mddev); return 0; } spin_lock_irq(&conf->device_lock); wait_event_lock_irq(conf->wait_for_stripe, conf->quiesce == 0, conf->device_lock, /* nothing */); atomic_inc(&conf->active_aligned_reads); spin_unlock_irq(&conf->device_lock); generic_make_request(align_bi); return 1; } else { rcu_read_unlock(); bio_put(align_bi); return 0; } } /* __get_priority_stripe - get the next stripe to process * * Full stripe writes are allowed to pass preread active stripes up until * the bypass_threshold is exceeded. In general the bypass_count * increments when the handle_list is handled before the hold_list; however, it * will not be incremented when STRIPE_IO_STARTED is sampled set signifying a * stripe with in flight i/o. The bypass_count will be reset when the * head of the hold_list has changed, i.e. the head was promoted to the * handle_list. */ static struct stripe_head *__get_priority_stripe(raid5_conf_t *conf) { struct stripe_head *sh; pr_debug("%s: handle: %s hold: %s full_writes: %d bypass_count: %d\n", __func__, list_empty(&conf->handle_list) ? "empty" : "busy", list_empty(&conf->hold_list) ? "empty" : "busy", atomic_read(&conf->pending_full_writes), conf->bypass_count); if (!list_empty(&conf->handle_list)) { sh = list_entry(conf->handle_list.next, typeof(*sh), lru); if (list_empty(&conf->hold_list)) conf->bypass_count = 0; else if (!test_bit(STRIPE_IO_STARTED, &sh->state)) { if (conf->hold_list.next == conf->last_hold) conf->bypass_count++; else { conf->last_hold = conf->hold_list.next; conf->bypass_count -= conf->bypass_threshold; if (conf->bypass_count < 0) conf->bypass_count = 0; } } } else if (!list_empty(&conf->hold_list) && ((conf->bypass_threshold && conf->bypass_count > conf->bypass_threshold) || atomic_read(&conf->pending_full_writes) == 0)) { sh = list_entry(conf->hold_list.next, typeof(*sh), lru); conf->bypass_count -= conf->bypass_threshold; if (conf->bypass_count < 0) conf->bypass_count = 0; } else return NULL; list_del_init(&sh->lru); atomic_inc(&sh->count); BUG_ON(atomic_read(&sh->count) != 1); return sh; } static int make_request(struct request_queue *q, struct bio * bi) { mddev_t *mddev = q->queuedata; raid5_conf_t *conf = mddev_to_conf(mddev); int dd_idx; sector_t new_sector; sector_t logical_sector, last_sector; struct stripe_head *sh; const int rw = bio_data_dir(bi); int cpu, remaining; if (unlikely(bio_barrier(bi))) { bio_endio(bi, -EOPNOTSUPP); return 0; } md_write_start(mddev, bi); cpu = part_stat_lock(); part_stat_inc(cpu, &mddev->gendisk->part0, ios[rw]); part_stat_add(cpu, &mddev->gendisk->part0, sectors[rw], bio_sectors(bi)); part_stat_unlock(); if (rw == READ && mddev->reshape_position == MaxSector && chunk_aligned_read(q,bi)) return 0; logical_sector = bi->bi_sector & ~((sector_t)STRIPE_SECTORS-1); last_sector = bi->bi_sector + (bi->bi_size>>9); bi->bi_next = NULL; bi->bi_phys_segments = 1; /* over-loaded to count active stripes */ for (;logical_sector < last_sector; logical_sector += STRIPE_SECTORS) { DEFINE_WAIT(w); int disks, data_disks; int previous; retry: previous = 0; prepare_to_wait(&conf->wait_for_overlap, &w, TASK_UNINTERRUPTIBLE); if (likely(conf->reshape_progress == MaxSector)) disks = conf->raid_disks; else { /* spinlock is needed as reshape_progress may be * 64bit on a 32bit platform, and so it might be * possible to see a half-updated value * Ofcourse reshape_progress could change after * the lock is dropped, so once we get a reference * to the stripe that we think it is, we will have * to check again. */ spin_lock_irq(&conf->device_lock); disks = conf->raid_disks; if (mddev->delta_disks < 0 ? logical_sector < conf->reshape_progress : logical_sector >= conf->reshape_progress) { disks = conf->previous_raid_disks; previous = 1; } else { if (mddev->delta_disks < 0 ? logical_sector < conf->reshape_safe : logical_sector >= conf->reshape_safe) { spin_unlock_irq(&conf->device_lock); schedule(); goto retry; } } spin_unlock_irq(&conf->device_lock); } data_disks = disks - conf->max_degraded; new_sector = raid5_compute_sector(conf, logical_sector, previous, &dd_idx, NULL); pr_debug("raid5: make_request, sector %llu logical %llu\n", (unsigned long long)new_sector, (unsigned long long)logical_sector); sh = get_active_stripe(conf, new_sector, previous, (bi->bi_rw&RWA_MASK)); if (sh) { if (unlikely(conf->reshape_progress != MaxSector)) { /* expansion might have moved on while waiting for a * stripe, so we must do the range check again. * Expansion could still move past after this * test, but as we are holding a reference to * 'sh', we know that if that happens, * STRIPE_EXPANDING will get set and the expansion * won't proceed until we finish with the stripe. */ int must_retry = 0; spin_lock_irq(&conf->device_lock); if ((mddev->delta_disks < 0 ? logical_sector >= conf->reshape_progress : logical_sector < conf->reshape_progress) && previous) /* mismatch, need to try again */ must_retry = 1; spin_unlock_irq(&conf->device_lock); if (must_retry) { release_stripe(sh); goto retry; } } /* FIXME what if we get a false positive because these * are being updated. */ if (logical_sector >= mddev->suspend_lo && logical_sector < mddev->suspend_hi) { release_stripe(sh); schedule(); goto retry; } if (test_bit(STRIPE_EXPANDING, &sh->state) || !add_stripe_bio(sh, bi, dd_idx, (bi->bi_rw&RW_MASK))) { /* Stripe is busy expanding or * add failed due to overlap. Flush everything * and wait a while */ raid5_unplug_device(mddev->queue); release_stripe(sh); schedule(); goto retry; } finish_wait(&conf->wait_for_overlap, &w); set_bit(STRIPE_HANDLE, &sh->state); clear_bit(STRIPE_DELAYED, &sh->state); release_stripe(sh); } else { /* cannot get stripe for read-ahead, just give-up */ clear_bit(BIO_UPTODATE, &bi->bi_flags); finish_wait(&conf->wait_for_overlap, &w); break; } } spin_lock_irq(&conf->device_lock); remaining = raid5_dec_bi_phys_segments(bi); spin_unlock_irq(&conf->device_lock); if (remaining == 0) { if ( rw == WRITE ) md_write_end(mddev); bio_endio(bi, 0); } return 0; } static sector_t raid5_size(mddev_t *mddev, sector_t sectors, int raid_disks); static sector_t reshape_request(mddev_t *mddev, sector_t sector_nr, int *skipped) { /* reshaping is quite different to recovery/resync so it is * handled quite separately ... here. * * On each call to sync_request, we gather one chunk worth of * destination stripes and flag them as expanding. * Then we find all the source stripes and request reads. * As the reads complete, handle_stripe will copy the data * into the destination stripe and release that stripe. */ raid5_conf_t *conf = (raid5_conf_t *) mddev->private; struct stripe_head *sh; sector_t first_sector, last_sector; int raid_disks = conf->previous_raid_disks; int data_disks = raid_disks - conf->max_degraded; int new_data_disks = conf->raid_disks - conf->max_degraded; int i; int dd_idx; sector_t writepos, safepos, gap; sector_t stripe_addr; int reshape_sectors; struct list_head stripes; if (sector_nr == 0) { /* If restarting in the middle, skip the initial sectors */ if (mddev->delta_disks < 0 && conf->reshape_progress < raid5_size(mddev, 0, 0)) { sector_nr = raid5_size(mddev, 0, 0) - conf->reshape_progress; } else if (mddev->delta_disks > 0 && conf->reshape_progress > 0) sector_nr = conf->reshape_progress; sector_div(sector_nr, new_data_disks); if (sector_nr) { *skipped = 1; return sector_nr; } } /* We need to process a full chunk at a time. * If old and new chunk sizes differ, we need to process the * largest of these */ if (mddev->new_chunk > mddev->chunk_size) reshape_sectors = mddev->new_chunk / 512; else reshape_sectors = mddev->chunk_size / 512; /* we update the metadata when there is more than 3Meg * in the block range (that is rather arbitrary, should * probably be time based) or when the data about to be * copied would over-write the source of the data at * the front of the range. * i.e. one new_stripe along from reshape_progress new_maps * to after where reshape_safe old_maps to */ writepos = conf->reshape_progress; sector_div(writepos, new_data_disks); safepos = conf->reshape_safe; sector_div(safepos, data_disks); if (mddev->delta_disks < 0) { writepos -= reshape_sectors; safepos += reshape_sectors; gap = conf->reshape_safe - conf->reshape_progress; } else { writepos += reshape_sectors; safepos -= reshape_sectors; gap = conf->reshape_progress - conf->reshape_safe; } if ((mddev->delta_disks < 0 ? writepos < safepos : writepos > safepos) || gap > (new_data_disks)*3000*2 /*3Meg*/) { /* Cannot proceed until we've updated the superblock... */ wait_event(conf->wait_for_overlap, atomic_read(&conf->reshape_stripes)==0); mddev->reshape_position = conf->reshape_progress; set_bit(MD_CHANGE_DEVS, &mddev->flags); md_wakeup_thread(mddev->thread); wait_event(mddev->sb_wait, mddev->flags == 0 || kthread_should_stop()); spin_lock_irq(&conf->device_lock); conf->reshape_safe = mddev->reshape_position; spin_unlock_irq(&conf->device_lock); wake_up(&conf->wait_for_overlap); } if (mddev->delta_disks < 0) { BUG_ON(conf->reshape_progress == 0); stripe_addr = writepos; BUG_ON((mddev->dev_sectors & ~((sector_t)reshape_sectors - 1)) - reshape_sectors - stripe_addr != sector_nr); } else { BUG_ON(writepos != sector_nr + reshape_sectors); stripe_addr = sector_nr; } INIT_LIST_HEAD(&stripes); for (i = 0; i < reshape_sectors; i += STRIPE_SECTORS) { int j; int skipped = 0; sh = get_active_stripe(conf, stripe_addr+i, 0, 0); set_bit(STRIPE_EXPANDING, &sh->state); atomic_inc(&conf->reshape_stripes); /* If any of this stripe is beyond the end of the old * array, then we need to zero those blocks */ for (j=sh->disks; j--;) { sector_t s; if (j == sh->pd_idx) continue; if (conf->level == 6 && j == sh->qd_idx) continue; s = compute_blocknr(sh, j, 0); if (s < raid5_size(mddev, 0, 0)) { skipped = 1; continue; } memset(page_address(sh->dev[j].page), 0, STRIPE_SIZE); set_bit(R5_Expanded, &sh->dev[j].flags); set_bit(R5_UPTODATE, &sh->dev[j].flags); } if (!skipped) { set_bit(STRIPE_EXPAND_READY, &sh->state); set_bit(STRIPE_HANDLE, &sh->state); } list_add(&sh->lru, &stripes); } spin_lock_irq(&conf->device_lock); if (mddev->delta_disks < 0) conf->reshape_progress -= reshape_sectors * new_data_disks; else conf->reshape_progress += reshape_sectors * new_data_disks; spin_unlock_irq(&conf->device_lock); /* Ok, those stripe are ready. We can start scheduling * reads on the source stripes. * The source stripes are determined by mapping the first and last * block on the destination stripes. */ first_sector = raid5_compute_sector(conf, stripe_addr*(new_data_disks), 1, &dd_idx, NULL); last_sector = raid5_compute_sector(conf, ((stripe_addr+conf->chunk_size/512) *(new_data_disks) - 1), 1, &dd_idx, NULL); if (last_sector >= mddev->dev_sectors) last_sector = mddev->dev_sectors - 1; while (first_sector <= last_sector) { sh = get_active_stripe(conf, first_sector, 1, 0); set_bit(STRIPE_EXPAND_SOURCE, &sh->state); set_bit(STRIPE_HANDLE, &sh->state); release_stripe(sh); first_sector += STRIPE_SECTORS; } /* Now that the sources are clearly marked, we can release * the destination stripes */ while (!list_empty(&stripes)) { sh = list_entry(stripes.next, struct stripe_head, lru); list_del_init(&sh->lru); release_stripe(sh); } /* If this takes us to the resync_max point where we have to pause, * then we need to write out the superblock. */ sector_nr += reshape_sectors; if (sector_nr >= mddev->resync_max) { /* Cannot proceed until we've updated the superblock... */ wait_event(conf->wait_for_overlap, atomic_read(&conf->reshape_stripes) == 0); mddev->reshape_position = conf->reshape_progress; set_bit(MD_CHANGE_DEVS, &mddev->flags); md_wakeup_thread(mddev->thread); wait_event(mddev->sb_wait, !test_bit(MD_CHANGE_DEVS, &mddev->flags) || kthread_should_stop()); spin_lock_irq(&conf->device_lock); conf->reshape_safe = mddev->reshape_position; spin_unlock_irq(&conf->device_lock); wake_up(&conf->wait_for_overlap); } return reshape_sectors; } /* FIXME go_faster isn't used */ static inline sector_t sync_request(mddev_t *mddev, sector_t sector_nr, int *skipped, int go_faster) { raid5_conf_t *conf = (raid5_conf_t *) mddev->private; struct stripe_head *sh; sector_t max_sector = mddev->dev_sectors; int sync_blocks; int still_degraded = 0; int i; if (sector_nr >= max_sector) { /* just being told to finish up .. nothing much to do */ unplug_slaves(mddev); if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery)) { end_reshape(conf); return 0; } if (mddev->curr_resync < max_sector) /* aborted */ bitmap_end_sync(mddev->bitmap, mddev->curr_resync, &sync_blocks, 1); else /* completed sync */ conf->fullsync = 0; bitmap_close_sync(mddev->bitmap); return 0; } if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery)) return reshape_request(mddev, sector_nr, skipped); /* No need to check resync_max as we never do more than one * stripe, and as resync_max will always be on a chunk boundary, * if the check in md_do_sync didn't fire, there is no chance * of overstepping resync_max here */ /* if there is too many failed drives and we are trying * to resync, then assert that we are finished, because there is * nothing we can do. */ if (mddev->degraded >= conf->max_degraded && test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) { sector_t rv = mddev->dev_sectors - sector_nr; *skipped = 1; return rv; } if (!bitmap_start_sync(mddev->bitmap, sector_nr, &sync_blocks, 1) && !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery) && !conf->fullsync && sync_blocks >= STRIPE_SECTORS) { /* we can skip this block, and probably more */ sync_blocks /= STRIPE_SECTORS; *skipped = 1; return sync_blocks * STRIPE_SECTORS; /* keep things rounded to whole stripes */ } bitmap_cond_end_sync(mddev->bitmap, sector_nr); sh = get_active_stripe(conf, sector_nr, 0, 1); if (sh == NULL) { sh = get_active_stripe(conf, sector_nr, 0, 0); /* make sure we don't swamp the stripe cache if someone else * is trying to get access */ schedule_timeout_uninterruptible(1); } /* Need to check if array will still be degraded after recovery/resync * We don't need to check the 'failed' flag as when that gets set, * recovery aborts. */ for (i=0; iraid_disks; i++) if (conf->disks[i].rdev == NULL) still_degraded = 1; bitmap_start_sync(mddev->bitmap, sector_nr, &sync_blocks, still_degraded); spin_lock(&sh->lock); set_bit(STRIPE_SYNCING, &sh->state); clear_bit(STRIPE_INSYNC, &sh->state); spin_unlock(&sh->lock); /* wait for any blocked device to be handled */ while(unlikely(!handle_stripe(sh, NULL))) ; release_stripe(sh); return STRIPE_SECTORS; } static int retry_aligned_read(raid5_conf_t *conf, struct bio *raid_bio) { /* We may not be able to submit a whole bio at once as there * may not be enough stripe_heads available. * We cannot pre-allocate enough stripe_heads as we may need * more than exist in the cache (if we allow ever large chunks). * So we do one stripe head at a time and record in * ->bi_hw_segments how many have been done. * * We *know* that this entire raid_bio is in one chunk, so * it will be only one 'dd_idx' and only need one call to raid5_compute_sector. */ struct stripe_head *sh; int dd_idx; sector_t sector, logical_sector, last_sector; int scnt = 0; int remaining; int handled = 0; logical_sector = raid_bio->bi_sector & ~((sector_t)STRIPE_SECTORS-1); sector = raid5_compute_sector(conf, logical_sector, 0, &dd_idx, NULL); last_sector = raid_bio->bi_sector + (raid_bio->bi_size>>9); for (; logical_sector < last_sector; logical_sector += STRIPE_SECTORS, sector += STRIPE_SECTORS, scnt++) { if (scnt < raid5_bi_hw_segments(raid_bio)) /* already done this stripe */ continue; sh = get_active_stripe(conf, sector, 0, 1); if (!sh) { /* failed to get a stripe - must wait */ raid5_set_bi_hw_segments(raid_bio, scnt); conf->retry_read_aligned = raid_bio; return handled; } set_bit(R5_ReadError, &sh->dev[dd_idx].flags); if (!add_stripe_bio(sh, raid_bio, dd_idx, 0)) { release_stripe(sh); raid5_set_bi_hw_segments(raid_bio, scnt); conf->retry_read_aligned = raid_bio; return handled; } handle_stripe(sh, NULL); release_stripe(sh); handled++; } spin_lock_irq(&conf->device_lock); remaining = raid5_dec_bi_phys_segments(raid_bio); spin_unlock_irq(&conf->device_lock); if (remaining == 0) bio_endio(raid_bio, 0); if (atomic_dec_and_test(&conf->active_aligned_reads)) wake_up(&conf->wait_for_stripe); return handled; } /* * This is our raid5 kernel thread. * * We scan the hash table for stripes which can be handled now. * During the scan, completed stripes are saved for us by the interrupt * handler, so that they will not have to wait for our next wakeup. */ static void raid5d(mddev_t *mddev) { struct stripe_head *sh; raid5_conf_t *conf = mddev_to_conf(mddev); int handled; pr_debug("+++ raid5d active\n"); md_check_recovery(mddev); handled = 0; spin_lock_irq(&conf->device_lock); while (1) { struct bio *bio; if (conf->seq_flush != conf->seq_write) { int seq = conf->seq_flush; spin_unlock_irq(&conf->device_lock); bitmap_unplug(mddev->bitmap); spin_lock_irq(&conf->device_lock); conf->seq_write = seq; activate_bit_delay(conf); } while ((bio = remove_bio_from_retry(conf))) { int ok; spin_unlock_irq(&conf->device_lock); ok = retry_aligned_read(conf, bio); spin_lock_irq(&conf->device_lock); if (!ok) break; handled++; } sh = __get_priority_stripe(conf); if (!sh) break; spin_unlock_irq(&conf->device_lock); handled++; handle_stripe(sh, conf->spare_page); release_stripe(sh); spin_lock_irq(&conf->device_lock); } pr_debug("%d stripes handled\n", handled); spin_unlock_irq(&conf->device_lock); async_tx_issue_pending_all(); unplug_slaves(mddev); pr_debug("--- raid5d inactive\n"); } static ssize_t raid5_show_stripe_cache_size(mddev_t *mddev, char *page) { raid5_conf_t *conf = mddev_to_conf(mddev); if (conf) return sprintf(page, "%d\n", conf->max_nr_stripes); else return 0; } static ssize_t raid5_store_stripe_cache_size(mddev_t *mddev, const char *page, size_t len) { raid5_conf_t *conf = mddev_to_conf(mddev); unsigned long new; int err; if (len >= PAGE_SIZE) return -EINVAL; if (!conf) return -ENODEV; if (strict_strtoul(page, 10, &new)) return -EINVAL; if (new <= 16 || new > 32768) return -EINVAL; while (new < conf->max_nr_stripes) { if (drop_one_stripe(conf)) conf->max_nr_stripes--; else break; } err = md_allow_write(mddev); if (err) return err; while (new > conf->max_nr_stripes) { if (grow_one_stripe(conf)) conf->max_nr_stripes++; else break; } return len; } static struct md_sysfs_entry raid5_stripecache_size = __ATTR(stripe_cache_size, S_IRUGO | S_IWUSR, raid5_show_stripe_cache_size, raid5_store_stripe_cache_size); static ssize_t raid5_show_preread_threshold(mddev_t *mddev, char *page) { raid5_conf_t *conf = mddev_to_conf(mddev); if (conf) return sprintf(page, "%d\n", conf->bypass_threshold); else return 0; } static ssize_t raid5_store_preread_threshold(mddev_t *mddev, const char *page, size_t len) { raid5_conf_t *conf = mddev_to_conf(mddev); unsigned long new; if (len >= PAGE_SIZE) return -EINVAL; if (!conf) return -ENODEV; if (strict_strtoul(page, 10, &new)) return -EINVAL; if (new > conf->max_nr_stripes) return -EINVAL; conf->bypass_threshold = new; return len; } static struct md_sysfs_entry raid5_preread_bypass_threshold = __ATTR(preread_bypass_threshold, S_IRUGO | S_IWUSR, raid5_show_preread_threshold, raid5_store_preread_threshold); static ssize_t stripe_cache_active_show(mddev_t *mddev, char *page) { raid5_conf_t *conf = mddev_to_conf(mddev); if (conf) return sprintf(page, "%d\n", atomic_read(&conf->active_stripes)); else return 0; } static struct md_sysfs_entry raid5_stripecache_active = __ATTR_RO(stripe_cache_active); static struct attribute *raid5_attrs[] = { &raid5_stripecache_size.attr, &raid5_stripecache_active.attr, &raid5_preread_bypass_threshold.attr, NULL, }; static struct attribute_group raid5_attrs_group = { .name = NULL, .attrs = raid5_attrs, }; static sector_t raid5_size(mddev_t *mddev, sector_t sectors, int raid_disks) { raid5_conf_t *conf = mddev_to_conf(mddev); if (!sectors) sectors = mddev->dev_sectors; if (!raid_disks) { /* size is defined by the smallest of previous and new size */ if (conf->raid_disks < conf->previous_raid_disks) raid_disks = conf->raid_disks; else raid_disks = conf->previous_raid_disks; } sectors &= ~((sector_t)mddev->chunk_size/512 - 1); sectors &= ~((sector_t)mddev->new_chunk/512 - 1); return sectors * (raid_disks - conf->max_degraded); } static raid5_conf_t *setup_conf(mddev_t *mddev) { raid5_conf_t *conf; int raid_disk, memory; mdk_rdev_t *rdev; struct disk_info *disk; if (mddev->new_level != 5 && mddev->new_level != 4 && mddev->new_level != 6) { printk(KERN_ERR "raid5: %s: raid level not set to 4/5/6 (%d)\n", mdname(mddev), mddev->new_level); return ERR_PTR(-EIO); } if ((mddev->new_level == 5 && !algorithm_valid_raid5(mddev->new_layout)) || (mddev->new_level == 6 && !algorithm_valid_raid6(mddev->new_layout))) { printk(KERN_ERR "raid5: %s: layout %d not supported\n", mdname(mddev), mddev->new_layout); return ERR_PTR(-EIO); } if (mddev->new_level == 6 && mddev->raid_disks < 4) { printk(KERN_ERR "raid6: not enough configured devices for %s (%d, minimum 4)\n", mdname(mddev), mddev->raid_disks); return ERR_PTR(-EINVAL); } if (!mddev->new_chunk || mddev->new_chunk % PAGE_SIZE) { printk(KERN_ERR "raid5: invalid chunk size %d for %s\n", mddev->new_chunk, mdname(mddev)); return ERR_PTR(-EINVAL); } conf = kzalloc(sizeof(raid5_conf_t), GFP_KERNEL); if (conf == NULL) goto abort; conf->raid_disks = mddev->raid_disks; if (mddev->reshape_position == MaxSector) conf->previous_raid_disks = mddev->raid_disks; else conf->previous_raid_disks = mddev->raid_disks - mddev->delta_disks; conf->disks = kzalloc(conf->raid_disks * sizeof(struct disk_info), GFP_KERNEL); if (!conf->disks) goto abort; conf->mddev = mddev; if ((conf->stripe_hashtbl = kzalloc(PAGE_SIZE, GFP_KERNEL)) == NULL) goto abort; if (mddev->new_level == 6) { conf->spare_page = alloc_page(GFP_KERNEL); if (!conf->spare_page) goto abort; } spin_lock_init(&conf->device_lock); init_waitqueue_head(&conf->wait_for_stripe); init_waitqueue_head(&conf->wait_for_overlap); INIT_LIST_HEAD(&conf->handle_list); INIT_LIST_HEAD(&conf->hold_list); INIT_LIST_HEAD(&conf->delayed_list); INIT_LIST_HEAD(&conf->bitmap_list); INIT_LIST_HEAD(&conf->inactive_list); atomic_set(&conf->active_stripes, 0); atomic_set(&conf->preread_active_stripes, 0); atomic_set(&conf->active_aligned_reads, 0); conf->bypass_threshold = BYPASS_THRESHOLD; pr_debug("raid5: run(%s) called.\n", mdname(mddev)); list_for_each_entry(rdev, &mddev->disks, same_set) { raid_disk = rdev->raid_disk; if (raid_disk >= conf->raid_disks || raid_disk < 0) continue; disk = conf->disks + raid_disk; disk->rdev = rdev; if (test_bit(In_sync, &rdev->flags)) { char b[BDEVNAME_SIZE]; printk(KERN_INFO "raid5: device %s operational as raid" " disk %d\n", bdevname(rdev->bdev,b), raid_disk); } else /* Cannot rely on bitmap to complete recovery */ conf->fullsync = 1; } conf->chunk_size = mddev->new_chunk; conf->level = mddev->new_level; if (conf->level == 6) conf->max_degraded = 2; else conf->max_degraded = 1; conf->algorithm = mddev->new_layout; conf->max_nr_stripes = NR_STRIPES; conf->reshape_progress = mddev->reshape_position; if (conf->reshape_progress != MaxSector) { conf->prev_chunk = mddev->chunk_size; conf->prev_algo = mddev->layout; } memory = conf->max_nr_stripes * (sizeof(struct stripe_head) + conf->raid_disks * ((sizeof(struct bio) + PAGE_SIZE))) / 1024; if (grow_stripes(conf, conf->max_nr_stripes)) { printk(KERN_ERR "raid5: couldn't allocate %dkB for buffers\n", memory); goto abort; } else printk(KERN_INFO "raid5: allocated %dkB for %s\n", memory, mdname(mddev)); conf->thread = md_register_thread(raid5d, mddev, "%s_raid5"); if (!conf->thread) { printk(KERN_ERR "raid5: couldn't allocate thread for %s\n", mdname(mddev)); goto abort; } return conf; abort: if (conf) { shrink_stripes(conf); safe_put_page(conf->spare_page); kfree(conf->disks); kfree(conf->stripe_hashtbl); kfree(conf); return ERR_PTR(-EIO); } else return ERR_PTR(-ENOMEM); } static int run(mddev_t *mddev) { raid5_conf_t *conf; int working_disks = 0; mdk_rdev_t *rdev; if (mddev->reshape_position != MaxSector) { /* Check that we can continue the reshape. * Currently only disks can change, it must * increase, and we must be past the point where * a stripe over-writes itself */ sector_t here_new, here_old; int old_disks; int max_degraded = (mddev->level == 6 ? 2 : 1); if (mddev->new_level != mddev->level) { printk(KERN_ERR "raid5: %s: unsupported reshape " "required - aborting.\n", mdname(mddev)); return -EINVAL; } old_disks = mddev->raid_disks - mddev->delta_disks; /* reshape_position must be on a new-stripe boundary, and one * further up in new geometry must map after here in old * geometry. */ here_new = mddev->reshape_position; if (sector_div(here_new, (mddev->new_chunk>>9)* (mddev->raid_disks - max_degraded))) { printk(KERN_ERR "raid5: reshape_position not " "on a stripe boundary\n"); return -EINVAL; } /* here_new is the stripe we will write to */ here_old = mddev->reshape_position; sector_div(here_old, (mddev->chunk_size>>9)* (old_disks-max_degraded)); /* here_old is the first stripe that we might need to read * from */ if (here_new >= here_old) { /* Reading from the same stripe as writing to - bad */ printk(KERN_ERR "raid5: reshape_position too early for " "auto-recovery - aborting.\n"); return -EINVAL; } printk(KERN_INFO "raid5: reshape will continue\n"); /* OK, we should be able to continue; */ } else { BUG_ON(mddev->level != mddev->new_level); BUG_ON(mddev->layout != mddev->new_layout); BUG_ON(mddev->chunk_size != mddev->new_chunk); BUG_ON(mddev->delta_disks != 0); } if (mddev->private == NULL) conf = setup_conf(mddev); else conf = mddev->private; if (IS_ERR(conf)) return PTR_ERR(conf); mddev->thread = conf->thread; conf->thread = NULL; mddev->private = conf; /* * 0 for a fully functional array, 1 or 2 for a degraded array. */ list_for_each_entry(rdev, &mddev->disks, same_set) if (rdev->raid_disk >= 0 && test_bit(In_sync, &rdev->flags)) working_disks++; mddev->degraded = conf->raid_disks - working_disks; if (mddev->degraded > conf->max_degraded) { printk(KERN_ERR "raid5: not enough operational devices for %s" " (%d/%d failed)\n", mdname(mddev), mddev->degraded, conf->raid_disks); goto abort; } /* device size must be a multiple of chunk size */ mddev->dev_sectors &= ~(mddev->chunk_size / 512 - 1); mddev->resync_max_sectors = mddev->dev_sectors; if (mddev->degraded > 0 && mddev->recovery_cp != MaxSector) { if (mddev->ok_start_degraded) printk(KERN_WARNING "raid5: starting dirty degraded array: %s" "- data corruption possible.\n", mdname(mddev)); else { printk(KERN_ERR "raid5: cannot start dirty degraded array for %s\n", mdname(mddev)); goto abort; } } if (mddev->degraded == 0) printk("raid5: raid level %d set %s active with %d out of %d" " devices, algorithm %d\n", conf->level, mdname(mddev), mddev->raid_disks-mddev->degraded, mddev->raid_disks, mddev->new_layout); else printk(KERN_ALERT "raid5: raid level %d set %s active with %d" " out of %d devices, algorithm %d\n", conf->level, mdname(mddev), mddev->raid_disks - mddev->degraded, mddev->raid_disks, mddev->new_layout); print_raid5_conf(conf); if (conf->reshape_progress != MaxSector) { printk("...ok start reshape thread\n"); conf->reshape_safe = conf->reshape_progress; atomic_set(&conf->reshape_stripes, 0); clear_bit(MD_RECOVERY_SYNC, &mddev->recovery); clear_bit(MD_RECOVERY_CHECK, &mddev->recovery); set_bit(MD_RECOVERY_RESHAPE, &mddev->recovery); set_bit(MD_RECOVERY_RUNNING, &mddev->recovery); mddev->sync_thread = md_register_thread(md_do_sync, mddev, "%s_reshape"); } /* read-ahead size must cover two whole stripes, which is * 2 * (datadisks) * chunksize where 'n' is the number of raid devices */ { int data_disks = conf->previous_raid_disks - conf->max_degraded; int stripe = data_disks * (mddev->chunk_size / PAGE_SIZE); if (mddev->queue->backing_dev_info.ra_pages < 2 * stripe) mddev->queue->backing_dev_info.ra_pages = 2 * stripe; } /* Ok, everything is just fine now */ if (sysfs_create_group(&mddev->kobj, &raid5_attrs_group)) printk(KERN_WARNING "raid5: failed to create sysfs attributes for %s\n", mdname(mddev)); mddev->queue->queue_lock = &conf->device_lock; mddev->queue->unplug_fn = raid5_unplug_device; mddev->queue->backing_dev_info.congested_data = mddev; mddev->queue->backing_dev_info.congested_fn = raid5_congested; md_set_array_sectors(mddev, raid5_size(mddev, 0, 0)); blk_queue_merge_bvec(mddev->queue, raid5_mergeable_bvec); return 0; abort: md_unregister_thread(mddev->thread); mddev->thread = NULL; if (conf) { shrink_stripes(conf); print_raid5_conf(conf); safe_put_page(conf->spare_page); kfree(conf->disks); kfree(conf->stripe_hashtbl); kfree(conf); } mddev->private = NULL; printk(KERN_ALERT "raid5: failed to run raid set %s\n", mdname(mddev)); return -EIO; } static int stop(mddev_t *mddev) { raid5_conf_t *conf = (raid5_conf_t *) mddev->private; md_unregister_thread(mddev->thread); mddev->thread = NULL; shrink_stripes(conf); kfree(conf->stripe_hashtbl); mddev->queue->backing_dev_info.congested_fn = NULL; blk_sync_queue(mddev->queue); /* the unplug fn references 'conf'*/ sysfs_remove_group(&mddev->kobj, &raid5_attrs_group); kfree(conf->disks); kfree(conf); mddev->private = NULL; return 0; } #ifdef DEBUG static void print_sh(struct seq_file *seq, struct stripe_head *sh) { int i; seq_printf(seq, "sh %llu, pd_idx %d, state %ld.\n", (unsigned long long)sh->sector, sh->pd_idx, sh->state); seq_printf(seq, "sh %llu, count %d.\n", (unsigned long long)sh->sector, atomic_read(&sh->count)); seq_printf(seq, "sh %llu, ", (unsigned long long)sh->sector); for (i = 0; i < sh->disks; i++) { seq_printf(seq, "(cache%d: %p %ld) ", i, sh->dev[i].page, sh->dev[i].flags); } seq_printf(seq, "\n"); } static void printall(struct seq_file *seq, raid5_conf_t *conf) { struct stripe_head *sh; struct hlist_node *hn; int i; spin_lock_irq(&conf->device_lock); for (i = 0; i < NR_HASH; i++) { hlist_for_each_entry(sh, hn, &conf->stripe_hashtbl[i], hash) { if (sh->raid_conf != conf) continue; print_sh(seq, sh); } } spin_unlock_irq(&conf->device_lock); } #endif static void status(struct seq_file *seq, mddev_t *mddev) { raid5_conf_t *conf = (raid5_conf_t *) mddev->private; int i; seq_printf (seq, " level %d, %dk chunk, algorithm %d", mddev->level, mddev->chunk_size >> 10, mddev->layout); seq_printf (seq, " [%d/%d] [", conf->raid_disks, conf->raid_disks - mddev->degraded); for (i = 0; i < conf->raid_disks; i++) seq_printf (seq, "%s", conf->disks[i].rdev && test_bit(In_sync, &conf->disks[i].rdev->flags) ? "U" : "_"); seq_printf (seq, "]"); #ifdef DEBUG seq_printf (seq, "\n"); printall(seq, conf); #endif } static void print_raid5_conf (raid5_conf_t *conf) { int i; struct disk_info *tmp; printk("RAID5 conf printout:\n"); if (!conf) { printk("(conf==NULL)\n"); return; } printk(" --- rd:%d wd:%d\n", conf->raid_disks, conf->raid_disks - conf->mddev->degraded); for (i = 0; i < conf->raid_disks; i++) { char b[BDEVNAME_SIZE]; tmp = conf->disks + i; if (tmp->rdev) printk(" disk %d, o:%d, dev:%s\n", i, !test_bit(Faulty, &tmp->rdev->flags), bdevname(tmp->rdev->bdev,b)); } } static int raid5_spare_active(mddev_t *mddev) { int i; raid5_conf_t *conf = mddev->private; struct disk_info *tmp; for (i = 0; i < conf->raid_disks; i++) { tmp = conf->disks + i; if (tmp->rdev && !test_bit(Faulty, &tmp->rdev->flags) && !test_and_set_bit(In_sync, &tmp->rdev->flags)) { unsigned long flags; spin_lock_irqsave(&conf->device_lock, flags); mddev->degraded--; spin_unlock_irqrestore(&conf->device_lock, flags); } } print_raid5_conf(conf); return 0; } static int raid5_remove_disk(mddev_t *mddev, int number) { raid5_conf_t *conf = mddev->private; int err = 0; mdk_rdev_t *rdev; struct disk_info *p = conf->disks + number; print_raid5_conf(conf); rdev = p->rdev; if (rdev) { if (number >= conf->raid_disks && conf->reshape_progress == MaxSector) clear_bit(In_sync, &rdev->flags); if (test_bit(In_sync, &rdev->flags) || atomic_read(&rdev->nr_pending)) { err = -EBUSY; goto abort; } /* Only remove non-faulty devices if recovery * isn't possible. */ if (!test_bit(Faulty, &rdev->flags) && mddev->degraded <= conf->max_degraded && number < conf->raid_disks) { err = -EBUSY; goto abort; } p->rdev = NULL; synchronize_rcu(); if (atomic_read(&rdev->nr_pending)) { /* lost the race, try later */ err = -EBUSY; p->rdev = rdev; } } abort: print_raid5_conf(conf); return err; } static int raid5_add_disk(mddev_t *mddev, mdk_rdev_t *rdev) { raid5_conf_t *conf = mddev->private; int err = -EEXIST; int disk; struct disk_info *p; int first = 0; int last = conf->raid_disks - 1; if (mddev->degraded > conf->max_degraded) /* no point adding a device */ return -EINVAL; if (rdev->raid_disk >= 0) first = last = rdev->raid_disk; /* * find the disk ... but prefer rdev->saved_raid_disk * if possible. */ if (rdev->saved_raid_disk >= 0 && rdev->saved_raid_disk >= first && conf->disks[rdev->saved_raid_disk].rdev == NULL) disk = rdev->saved_raid_disk; else disk = first; for ( ; disk <= last ; disk++) if ((p=conf->disks + disk)->rdev == NULL) { clear_bit(In_sync, &rdev->flags); rdev->raid_disk = disk; err = 0; if (rdev->saved_raid_disk != disk) conf->fullsync = 1; rcu_assign_pointer(p->rdev, rdev); break; } print_raid5_conf(conf); return err; } static int raid5_resize(mddev_t *mddev, sector_t sectors) { /* no resync is happening, and there is enough space * on all devices, so we can resize. * We need to make sure resync covers any new space. * If the array is shrinking we should possibly wait until * any io in the removed space completes, but it hardly seems * worth it. */ sectors &= ~((sector_t)mddev->chunk_size/512 - 1); md_set_array_sectors(mddev, raid5_size(mddev, sectors, mddev->raid_disks)); if (mddev->array_sectors > raid5_size(mddev, sectors, mddev->raid_disks)) return -EINVAL; set_capacity(mddev->gendisk, mddev->array_sectors); mddev->changed = 1; if (sectors > mddev->dev_sectors && mddev->recovery_cp == MaxSector) { mddev->recovery_cp = mddev->dev_sectors; set_bit(MD_RECOVERY_NEEDED, &mddev->recovery); } mddev->dev_sectors = sectors; mddev->resync_max_sectors = sectors; return 0; } static int raid5_check_reshape(mddev_t *mddev) { raid5_conf_t *conf = mddev_to_conf(mddev); if (mddev->delta_disks == 0 && mddev->new_layout == mddev->layout && mddev->new_chunk == mddev->chunk_size) return -EINVAL; /* nothing to do */ if (mddev->bitmap) /* Cannot grow a bitmap yet */ return -EBUSY; if (mddev->degraded > conf->max_degraded) return -EINVAL; if (mddev->delta_disks < 0) { /* We might be able to shrink, but the devices must * be made bigger first. * For raid6, 4 is the minimum size. * Otherwise 2 is the minimum */ int min = 2; if (mddev->level == 6) min = 4; if (mddev->raid_disks + mddev->delta_disks < min) return -EINVAL; } /* Can only proceed if there are plenty of stripe_heads. * We need a minimum of one full stripe,, and for sensible progress * it is best to have about 4 times that. * If we require 4 times, then the default 256 4K stripe_heads will * allow for chunk sizes up to 256K, which is probably OK. * If the chunk size is greater, user-space should request more * stripe_heads first. */ if ((mddev->chunk_size / STRIPE_SIZE) * 4 > conf->max_nr_stripes || (mddev->new_chunk / STRIPE_SIZE) * 4 > conf->max_nr_stripes) { printk(KERN_WARNING "raid5: reshape: not enough stripes. Needed %lu\n", (max(mddev->chunk_size, mddev->new_chunk) / STRIPE_SIZE)*4); return -ENOSPC; } return resize_stripes(conf, conf->raid_disks + mddev->delta_disks); } static int raid5_start_reshape(mddev_t *mddev) { raid5_conf_t *conf = mddev_to_conf(mddev); mdk_rdev_t *rdev; int spares = 0; int added_devices = 0; unsigned long flags; if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery)) return -EBUSY; list_for_each_entry(rdev, &mddev->disks, same_set) if (rdev->raid_disk < 0 && !test_bit(Faulty, &rdev->flags)) spares++; if (spares - mddev->degraded < mddev->delta_disks - conf->max_degraded) /* Not enough devices even to make a degraded array * of that size */ return -EINVAL; /* Refuse to reduce size of the array. Any reductions in * array size must be through explicit setting of array_size * attribute. */ if (raid5_size(mddev, 0, conf->raid_disks + mddev->delta_disks) < mddev->array_sectors) { printk(KERN_ERR "md: %s: array size must be reduced " "before number of disks\n", mdname(mddev)); return -EINVAL; } atomic_set(&conf->reshape_stripes, 0); spin_lock_irq(&conf->device_lock); conf->previous_raid_disks = conf->raid_disks; conf->raid_disks += mddev->delta_disks; conf->prev_chunk = conf->chunk_size; conf->chunk_size = mddev->new_chunk; conf->prev_algo = conf->algorithm; conf->algorithm = mddev->new_layout; if (mddev->delta_disks < 0) conf->reshape_progress = raid5_size(mddev, 0, 0); else conf->reshape_progress = 0; conf->reshape_safe = conf->reshape_progress; conf->generation++; spin_unlock_irq(&conf->device_lock); /* Add some new drives, as many as will fit. * We know there are enough to make the newly sized array work. */ list_for_each_entry(rdev, &mddev->disks, same_set) if (rdev->raid_disk < 0 && !test_bit(Faulty, &rdev->flags)) { if (raid5_add_disk(mddev, rdev) == 0) { char nm[20]; set_bit(In_sync, &rdev->flags); added_devices++; rdev->recovery_offset = 0; sprintf(nm, "rd%d", rdev->raid_disk); if (sysfs_create_link(&mddev->kobj, &rdev->kobj, nm)) printk(KERN_WARNING "raid5: failed to create " " link %s for %s\n", nm, mdname(mddev)); } else break; } if (mddev->delta_disks > 0) { spin_lock_irqsave(&conf->device_lock, flags); mddev->degraded = (conf->raid_disks - conf->previous_raid_disks) - added_devices; spin_unlock_irqrestore(&conf->device_lock, flags); } mddev->raid_disks = conf->raid_disks; mddev->reshape_position = 0; set_bit(MD_CHANGE_DEVS, &mddev->flags); clear_bit(MD_RECOVERY_SYNC, &mddev->recovery); clear_bit(MD_RECOVERY_CHECK, &mddev->recovery); set_bit(MD_RECOVERY_RESHAPE, &mddev->recovery); set_bit(MD_RECOVERY_RUNNING, &mddev->recovery); mddev->sync_thread = md_register_thread(md_do_sync, mddev, "%s_reshape"); if (!mddev->sync_thread) { mddev->recovery = 0; spin_lock_irq(&conf->device_lock); mddev->raid_disks = conf->raid_disks = conf->previous_raid_disks; conf->reshape_progress = MaxSector; spin_unlock_irq(&conf->device_lock); return -EAGAIN; } md_wakeup_thread(mddev->sync_thread); md_new_event(mddev); return 0; } /* This is called from the reshape thread and should make any * changes needed in 'conf' */ static void end_reshape(raid5_conf_t *conf) { if (!test_bit(MD_RECOVERY_INTR, &conf->mddev->recovery)) { spin_lock_irq(&conf->device_lock); conf->previous_raid_disks = conf->raid_disks; conf->reshape_progress = MaxSector; spin_unlock_irq(&conf->device_lock); /* read-ahead size must cover two whole stripes, which is * 2 * (datadisks) * chunksize where 'n' is the number of raid devices */ { int data_disks = conf->raid_disks - conf->max_degraded; int stripe = data_disks * (conf->chunk_size / PAGE_SIZE); if (conf->mddev->queue->backing_dev_info.ra_pages < 2 * stripe) conf->mddev->queue->backing_dev_info.ra_pages = 2 * stripe; } } } /* This is called from the raid5d thread with mddev_lock held. * It makes config changes to the device. */ static void raid5_finish_reshape(mddev_t *mddev) { struct block_device *bdev; raid5_conf_t *conf = mddev_to_conf(mddev); if (!test_bit(MD_RECOVERY_INTR, &mddev->recovery)) { if (mddev->delta_disks > 0) { md_set_array_sectors(mddev, raid5_size(mddev, 0, 0)); set_capacity(mddev->gendisk, mddev->array_sectors); mddev->changed = 1; bdev = bdget_disk(mddev->gendisk, 0); if (bdev) { mutex_lock(&bdev->bd_inode->i_mutex); i_size_write(bdev->bd_inode, (loff_t)mddev->array_sectors << 9); mutex_unlock(&bdev->bd_inode->i_mutex); bdput(bdev); } } else { int d; mddev->degraded = conf->raid_disks; for (d = 0; d < conf->raid_disks ; d++) if (conf->disks[d].rdev && test_bit(In_sync, &conf->disks[d].rdev->flags)) mddev->degraded--; for (d = conf->raid_disks ; d < conf->raid_disks - mddev->delta_disks; d++) raid5_remove_disk(mddev, d); } mddev->layout = conf->algorithm; mddev->chunk_size = conf->chunk_size; mddev->reshape_position = MaxSector; mddev->delta_disks = 0; } } static void raid5_quiesce(mddev_t *mddev, int state) { raid5_conf_t *conf = mddev_to_conf(mddev); switch(state) { case 2: /* resume for a suspend */ wake_up(&conf->wait_for_overlap); break; case 1: /* stop all writes */ spin_lock_irq(&conf->device_lock); conf->quiesce = 1; wait_event_lock_irq(conf->wait_for_stripe, atomic_read(&conf->active_stripes) == 0 && atomic_read(&conf->active_aligned_reads) == 0, conf->device_lock, /* nothing */); spin_unlock_irq(&conf->device_lock); break; case 0: /* re-enable writes */ spin_lock_irq(&conf->device_lock); conf->quiesce = 0; wake_up(&conf->wait_for_stripe); wake_up(&conf->wait_for_overlap); spin_unlock_irq(&conf->device_lock); break; } } static void *raid5_takeover_raid1(mddev_t *mddev) { int chunksect; if (mddev->raid_disks != 2 || mddev->degraded > 1) return ERR_PTR(-EINVAL); /* Should check if there are write-behind devices? */ chunksect = 64*2; /* 64K by default */ /* The array must be an exact multiple of chunksize */ while (chunksect && (mddev->array_sectors & (chunksect-1))) chunksect >>= 1; if ((chunksect<<9) < STRIPE_SIZE) /* array size does not allow a suitable chunk size */ return ERR_PTR(-EINVAL); mddev->new_level = 5; mddev->new_layout = ALGORITHM_LEFT_SYMMETRIC; mddev->new_chunk = chunksect << 9; return setup_conf(mddev); } static void *raid5_takeover_raid6(mddev_t *mddev) { int new_layout; switch (mddev->layout) { case ALGORITHM_LEFT_ASYMMETRIC_6: new_layout = ALGORITHM_LEFT_ASYMMETRIC; break; case ALGORITHM_RIGHT_ASYMMETRIC_6: new_layout = ALGORITHM_RIGHT_ASYMMETRIC; break; case ALGORITHM_LEFT_SYMMETRIC_6: new_layout = ALGORITHM_LEFT_SYMMETRIC; break; case ALGORITHM_RIGHT_SYMMETRIC_6: new_layout = ALGORITHM_RIGHT_SYMMETRIC; break; case ALGORITHM_PARITY_0_6: new_layout = ALGORITHM_PARITY_0; break; case ALGORITHM_PARITY_N: new_layout = ALGORITHM_PARITY_N; break; default: return ERR_PTR(-EINVAL); } mddev->new_level = 5; mddev->new_layout = new_layout; mddev->delta_disks = -1; mddev->raid_disks -= 1; return setup_conf(mddev); } static int raid5_reconfig(mddev_t *mddev, int new_layout, int new_chunk) { /* For a 2-drive array, the layout and chunk size can be changed * immediately as not restriping is needed. * For larger arrays we record the new value - after validation * to be used by a reshape pass. */ raid5_conf_t *conf = mddev_to_conf(mddev); if (new_layout >= 0 && !algorithm_valid_raid5(new_layout)) return -EINVAL; if (new_chunk > 0) { if (new_chunk & (new_chunk-1)) /* not a power of 2 */ return -EINVAL; if (new_chunk < PAGE_SIZE) return -EINVAL; if (mddev->array_sectors & ((new_chunk>>9)-1)) /* not factor of array size */ return -EINVAL; } /* They look valid */ if (mddev->raid_disks == 2) { if (new_layout >= 0) { conf->algorithm = new_layout; mddev->layout = mddev->new_layout = new_layout; } if (new_chunk > 0) { conf->chunk_size = new_chunk; mddev->chunk_size = mddev->new_chunk = new_chunk; } set_bit(MD_CHANGE_DEVS, &mddev->flags); md_wakeup_thread(mddev->thread); } else { if (new_layout >= 0) mddev->new_layout = new_layout; if (new_chunk > 0) mddev->new_chunk = new_chunk; } return 0; } static int raid6_reconfig(mddev_t *mddev, int new_layout, int new_chunk) { if (new_layout >= 0 && !algorithm_valid_raid6(new_layout)) return -EINVAL; if (new_chunk > 0) { if (new_chunk & (new_chunk-1)) /* not a power of 2 */ return -EINVAL; if (new_chunk < PAGE_SIZE) return -EINVAL; if (mddev->array_sectors & ((new_chunk>>9)-1)) /* not factor of array size */ return -EINVAL; } /* They look valid */ if (new_layout >= 0) mddev->new_layout = new_layout; if (new_chunk > 0) mddev->new_chunk = new_chunk; return 0; } static void *raid5_takeover(mddev_t *mddev) { /* raid5 can take over: * raid0 - if all devices are the same - make it a raid4 layout * raid1 - if there are two drives. We need to know the chunk size * raid4 - trivial - just use a raid4 layout. * raid6 - Providing it is a *_6 layout * * For now, just do raid1 */ if (mddev->level == 1) return raid5_takeover_raid1(mddev); if (mddev->level == 4) { mddev->new_layout = ALGORITHM_PARITY_N; mddev->new_level = 5; return setup_conf(mddev); } if (mddev->level == 6) return raid5_takeover_raid6(mddev); return ERR_PTR(-EINVAL); } static struct mdk_personality raid5_personality; static void *raid6_takeover(mddev_t *mddev) { /* Currently can only take over a raid5. We map the * personality to an equivalent raid6 personality * with the Q block at the end. */ int new_layout; if (mddev->pers != &raid5_personality) return ERR_PTR(-EINVAL); if (mddev->degraded > 1) return ERR_PTR(-EINVAL); if (mddev->raid_disks > 253) return ERR_PTR(-EINVAL); if (mddev->raid_disks < 3) return ERR_PTR(-EINVAL); switch (mddev->layout) { case ALGORITHM_LEFT_ASYMMETRIC: new_layout = ALGORITHM_LEFT_ASYMMETRIC_6; break; case ALGORITHM_RIGHT_ASYMMETRIC: new_layout = ALGORITHM_RIGHT_ASYMMETRIC_6; break; case ALGORITHM_LEFT_SYMMETRIC: new_layout = ALGORITHM_LEFT_SYMMETRIC_6; break; case ALGORITHM_RIGHT_SYMMETRIC: new_layout = ALGORITHM_RIGHT_SYMMETRIC_6; break; case ALGORITHM_PARITY_0: new_layout = ALGORITHM_PARITY_0_6; break; case ALGORITHM_PARITY_N: new_layout = ALGORITHM_PARITY_N; break; default: return ERR_PTR(-EINVAL); } mddev->new_level = 6; mddev->new_layout = new_layout; mddev->delta_disks = 1; mddev->raid_disks += 1; return setup_conf(mddev); } static struct mdk_personality raid6_personality = { .name = "raid6", .level = 6, .owner = THIS_MODULE, .make_request = make_request, .run = run, .stop = stop, .status = status, .error_handler = error, .hot_add_disk = raid5_add_disk, .hot_remove_disk= raid5_remove_disk, .spare_active = raid5_spare_active, .sync_request = sync_request, .resize = raid5_resize, .size = raid5_size, .check_reshape = raid5_check_reshape, .start_reshape = raid5_start_reshape, .finish_reshape = raid5_finish_reshape, .quiesce = raid5_quiesce, .takeover = raid6_takeover, .reconfig = raid6_reconfig, }; static struct mdk_personality raid5_personality = { .name = "raid5", .level = 5, .owner = THIS_MODULE, .make_request = make_request, .run = run, .stop = stop, .status = status, .error_handler = error, .hot_add_disk = raid5_add_disk, .hot_remove_disk= raid5_remove_disk, .spare_active = raid5_spare_active, .sync_request = sync_request, .resize = raid5_resize, .size = raid5_size, .check_reshape = raid5_check_reshape, .start_reshape = raid5_start_reshape, .finish_reshape = raid5_finish_reshape, .quiesce = raid5_quiesce, .takeover = raid5_takeover, .reconfig = raid5_reconfig, }; static struct mdk_personality raid4_personality = { .name = "raid4", .level = 4, .owner = THIS_MODULE, .make_request = make_request, .run = run, .stop = stop, .status = status, .error_handler = error, .hot_add_disk = raid5_add_disk, .hot_remove_disk= raid5_remove_disk, .spare_active = raid5_spare_active, .sync_request = sync_request, .resize = raid5_resize, .size = raid5_size, .check_reshape = raid5_check_reshape, .start_reshape = raid5_start_reshape, .finish_reshape = raid5_finish_reshape, .quiesce = raid5_quiesce, }; static int __init raid5_init(void) { register_md_personality(&raid6_personality); register_md_personality(&raid5_personality); register_md_personality(&raid4_personality); return 0; } static void raid5_exit(void) { unregister_md_personality(&raid6_personality); unregister_md_personality(&raid5_personality); unregister_md_personality(&raid4_personality); } module_init(raid5_init); module_exit(raid5_exit); MODULE_LICENSE("GPL"); MODULE_ALIAS("md-personality-4"); /* RAID5 */ MODULE_ALIAS("md-raid5"); MODULE_ALIAS("md-raid4"); MODULE_ALIAS("md-level-5"); MODULE_ALIAS("md-level-4"); MODULE_ALIAS("md-personality-8"); /* RAID6 */ MODULE_ALIAS("md-raid6"); MODULE_ALIAS("md-level-6"); /* This used to be two separate modules, they were: */ MODULE_ALIAS("raid5"); MODULE_ALIAS("raid6");