diff options
Diffstat (limited to 'drivers/md/raid5.c')
| -rw-r--r-- | drivers/md/raid5.c | 4776 |
1 files changed, 4776 insertions, 0 deletions
diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c new file mode 100644 index 0000000..a36a743 --- /dev/null +++ b/drivers/md/raid5.c @@ -0,0 +1,4776 @@ +/* + * 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 <linux/kthread.h> +#include "raid6.h" + +#include <linux/raid/bitmap.h> +#include <linux/async_tx.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))) + +#if !RAID6_USE_EMPTY_ZERO_PAGE +/* In .bss so it's zeroed */ +const char raid6_empty_zero_page[PAGE_SIZE] __attribute__((aligned(256))); +#endif + +/* + * 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); +} + +static inline int raid6_next_disk(int disk, int raid_disks) +{ + disk++; + return (disk < raid_disks) ? disk : 0; +} + +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; i<num ; i++) { + p = sh->dev[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; i<num; i++) { + struct page *page; + + if (!(page = alloc_page(GFP_KERNEL))) { + return 1; + } + sh->dev[i].page = page; + } + return 0; +} + +static void raid5_build_block(struct stripe_head *sh, int i); + +static void init_stripe(struct stripe_head *sh, sector_t sector, int pd_idx, int disks) +{ + 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->sector = sector; + sh->pd_idx = pd_idx; + sh->state = 0; + + sh->disks = disks; + + 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); + } + insert_hash(conf, sh); +} + +static struct stripe_head *__find_stripe(raid5_conf_t *conf, sector_t sector, int disks) +{ + 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->disks == disks) + 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 disks, + int pd_idx, 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, disks); + 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, pd_idx, disks); + } else { + if (atomic_read(&sh->count)) { + BUG_ON(!list_empty(&sh->lru)); + } 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], "raid5-%s", mdname(conf->mddev)); + sprintf(conf->cache_name[1], "raid5-%s-alt", 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; +} + +#ifdef CONFIG_MD_RAID5_RESHAPE +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; i<conf->pool_size; i++) + nsh->dev[i].page = osh->dev[i].page; + for( ; i<newsize; i++) + nsh->dev[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; i<conf->raid_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; +} +#endif + +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 ; i<disks; i++) + if (bi == &sh->dev[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 ; i<disks; i++) + if (bi == &sh->dev[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); + +static void raid5_build_block(struct stripe_head *sh, int i) +{ + 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); +} + +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(sector_t r_sector, unsigned int raid_disks, + unsigned int data_disks, unsigned int * dd_idx, + unsigned int * pd_idx, raid5_conf_t *conf) +{ + long stripe; + unsigned long chunk_number; + unsigned int chunk_offset; + sector_t new_sector; + int sectors_per_chunk = conf->chunk_size >> 9; + + /* 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. + */ + switch(conf->level) { + case 4: + *pd_idx = data_disks; + break; + case 5: + switch (conf->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; + default: + printk(KERN_ERR "raid5: unsupported algorithm %d\n", + conf->algorithm); + } + break; + case 6: + + /**** FIX THIS ****/ + switch (conf->algorithm) { + case ALGORITHM_LEFT_ASYMMETRIC: + *pd_idx = raid_disks - 1 - (stripe % raid_disks); + if (*pd_idx == raid_disks-1) + (*dd_idx)++; /* Q D D D P */ + else if (*dd_idx >= *pd_idx) + (*dd_idx) += 2; /* D D P Q D */ + break; + case ALGORITHM_RIGHT_ASYMMETRIC: + *pd_idx = stripe % raid_disks; + if (*pd_idx == raid_disks-1) + (*dd_idx)++; /* Q D D D P */ + 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); + *dd_idx = (*pd_idx + 2 + *dd_idx) % raid_disks; + break; + case ALGORITHM_RIGHT_SYMMETRIC: + *pd_idx = stripe % raid_disks; + *dd_idx = (*pd_idx + 2 + *dd_idx) % raid_disks; + break; + default: + printk(KERN_CRIT "raid6: unsupported algorithm %d\n", + conf->algorithm); + } + break; + } + + /* + * 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) +{ + 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 = conf->chunk_size >> 9; + sector_t stripe; + int chunk_offset; + int chunk_number, dummy1, dummy2, dd_idx = i; + sector_t r_sector; + + + 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 (conf->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; + default: + printk(KERN_ERR "raid5: unsupported algorithm %d\n", + conf->algorithm); + } + break; + case 6: + if (i == raid6_next_disk(sh->pd_idx, raid_disks)) + return 0; /* It is the Q disk */ + switch (conf->algorithm) { + case ALGORITHM_LEFT_ASYMMETRIC: + case ALGORITHM_RIGHT_ASYMMETRIC: + 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; + default: + printk(KERN_CRIT "raid6: unsupported algorithm %d\n", + conf->algorithm); + } + break; + } + + chunk_number = stripe * data_disks + i; + r_sector = (sector_t)chunk_number * sectors_per_chunk + chunk_offset; + + check = raid5_compute_sector(r_sector, raid_disks, data_disks, &dummy1, &dummy2, conf); + if (check != sh->sector || dummy1 != dd_idx || dummy2 != sh->pd_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) +{ + raid6_conf_t *conf = sh->raid_conf; + int i, pd_idx = sh->pd_idx, qd_idx, d0_idx, disks = sh->disks, count; + struct bio *chosen; + /**** FIX THIS: This could be very bad if disks is close to 256 ****/ + void *ptrs[disks]; + + qd_idx = raid6_next_disk(pd_idx, disks); + d0_idx = raid6_next_disk(qd_idx, disks); + + 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); + } + +// switch(method) { +// case RECONSTRUCT_WRITE: +// case CHECK_PARITY: +// case UPDATE_PARITY: + /* Note that unlike RAID-5, the ordering of the disks matters greatly. */ + /* FIX: Is this ordering of drives even remotely optimal? */ + count = 0; + i = d0_idx; + do { + ptrs[count++] = page_address(sh->dev[i].page); + if (count <= disks-2 && !test_bit(R5_UPTODATE, &sh->dev[i].flags)) + printk("block %d/%d not uptodate on parity calc\n", i,count); + i = raid6_next_disk(i, disks); + } while ( i != d0_idx ); +// break; +// } + + raid6_call.gen_syndrome(disks, 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 pd_idx = sh->pd_idx; + int qd_idx = raid6_next_disk(pd_idx, disks); + + 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 pd_idx = sh->pd_idx; + int qd_idx = raid6_next_disk(pd_idx, disks); + int d0_idx = raid6_next_disk(qd_idx, disks); + int faila, failb; + + /* faila and failb are disk numbers relative to d0_idx */ + /* pd_idx become disks-2 and qd_idx become disks-1 */ + faila = (dd_idx1 < d0_idx) ? dd_idx1+(disks-d0_idx) : dd_idx1-d0_idx; + failb = (dd_idx2 < d0_idx) ? dd_idx2+(disks-d0_idx) : dd_idx2-d0_idx; + + 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 == disks-1 ) { + /* Q disk is one of the missing disks */ + if ( faila == disks-2 ) { + /* 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 == qd_idx) ? dd_idx2 : dd_idx1, 0); + compute_parity6(sh, UPDATE_PARITY); /* Is this necessary? */ + return; + } + } + + /* We're missing D+P or D+D; build pointer table */ + { + /**** FIX THIS: This could be very bad if disks is close to 256 ****/ + void *ptrs[disks]; + + count = 0; + i = d0_idx; + do { + ptrs[count++] = page_address(sh->dev[i].page); + i = raid6_next_disk(i, disks); + if (i != dd_idx1 && i != dd_idx2 && + !test_bit(R5_UPTODATE, &sh->dev[i].flags)) + printk("compute_2 with missing block %d/%d\n", count, i); + } while ( i != d0_idx ); + + if ( failb == disks-2 ) { + /* We're missing D+P. */ + raid6_datap_recov(disks, STRIPE_SIZE, faila, ptrs); + } else { + /* We're missing D+D. */ + raid6_2data_recov(disks, 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 int stripe_to_pdidx(sector_t stripe, raid5_conf_t *conf, int disks) +{ + int sectors_per_chunk = conf->chunk_size >> 9; + int pd_idx, dd_idx; + int chunk_offset = sector_div(stripe, sectors_per_chunk); + + raid5_compute_sector(stripe * (disks - conf->max_degraded) + *sectors_per_chunk + chunk_offset, + disks, disks - conf->max_degraded, + &dd_idx, &pd_idx, conf); + return pd_idx; +} + +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 = r6s->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 = r6s->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 && (!r6s || i != r6s->qd_idx)) { + int dd_idx, pd_idx, j; + struct stripe_head *sh2; + + sector_t bn = compute_blocknr(sh, i); + sector_t s = raid5_compute_sector(bn, conf->raid_disks, + conf->raid_disks - + conf->max_degraded, &dd_idx, + &pd_idx, conf); + sh2 = get_active_stripe(conf, s, conf->raid_disks, + pd_idx, 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 != raid6_next_disk(sh2->pd_idx, + sh2->disks)) && + !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) { + 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; + sh->pd_idx = stripe_to_pdidx(sh->sector, conf, + conf->raid_disks); + 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) +{ + raid6_conf_t *conf = sh->raid_conf; + int disks = sh->disks; + struct bio *return_bi = NULL; + int i, pd_idx = sh->pd_idx; + struct stripe_head_state s; + struct r6_state r6s; + struct r5dev *dev, *pdev, *qdev; + mdk_rdev_t *blocked_rdev = NULL; + + r6s.qd_idx = raid6_next_disk(pd_idx, disks); + 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, r6s.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[r6s.qd_idx]; + r6s.q_failed = (s.failed >= 1 && r6s.failed_num[0] == r6s.qd_idx) + || (s.failed >= 2 && r6s.failed_num[1] == r6s.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)) { + /* Need to write out all blocks after computing P&Q */ + sh->disks = conf->raid_disks; + sh->pd_idx = stripe_to_pdidx(sh->sector, conf, + conf->raid_disks); + 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; i<mddev->raid_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 */ + + 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; + + 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); + const unsigned int raid_disks = conf->raid_disks; + const unsigned int data_disks = raid_disks - conf->max_degraded; + unsigned int dd_idx, pd_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(raid_bio->bi_sector, + raid_disks, + data_disks, + &dd_idx, + &pd_idx, + conf); + + 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); + unsigned int dd_idx, pd_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; + + retry: + prepare_to_wait(&conf->wait_for_overlap, &w, TASK_UNINTERRUPTIBLE); + if (likely(conf->expand_progress == MaxSector)) + disks = conf->raid_disks; + else { + /* spinlock is needed as expand_progress may be + * 64bit on a 32bit platform, and so it might be + * possible to see a half-updated value + * Ofcourse expand_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 (logical_sector >= conf->expand_progress) + disks = conf->previous_raid_disks; + else { + if (logical_sector >= conf->expand_lo) { + 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(logical_sector, disks, data_disks, + &dd_idx, &pd_idx, conf); + 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, disks, pd_idx, (bi->bi_rw&RWA_MASK)); + if (sh) { + if (unlikely(conf->expand_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 (logical_sector < conf->expand_progress && + disks == conf->previous_raid_disks) + /* 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 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; + int pd_idx; + 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; + + if (sector_nr == 0 && + conf->expand_progress != 0) { + /* restarting in the middle, skip the initial sectors */ + sector_nr = conf->expand_progress; + sector_div(sector_nr, new_data_disks); + *skipped = 1; + return sector_nr; + } + + /* 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 forward from expand_progress new_maps + * to after where expand_lo old_maps to + */ + writepos = conf->expand_progress + + conf->chunk_size/512*(new_data_disks); + sector_div(writepos, new_data_disks); + safepos = conf->expand_lo; + sector_div(safepos, data_disks); + gap = conf->expand_progress - conf->expand_lo; + + if (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->expand_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->expand_lo = mddev->reshape_position; + spin_unlock_irq(&conf->device_lock); + wake_up(&conf->wait_for_overlap); + } + + for (i=0; i < conf->chunk_size/512; i+= STRIPE_SECTORS) { + int j; + int skipped = 0; + pd_idx = stripe_to_pdidx(sector_nr+i, conf, conf->raid_disks); + sh = get_active_stripe(conf, sector_nr+i, + conf->raid_disks, pd_idx, 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 == raid6_next_disk(sh->pd_idx, sh->disks)) + continue; + s = compute_blocknr(sh, j); + if (s < mddev->array_sectors) { + 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); + } + release_stripe(sh); + } + spin_lock_irq(&conf->device_lock); + conf->expand_progress = (sector_nr + i) * 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(sector_nr*(new_data_disks), + raid_disks, data_disks, + &dd_idx, &pd_idx, conf); + last_sector = + raid5_compute_sector((sector_nr+conf->chunk_size/512) + *(new_data_disks) -1, + raid_disks, data_disks, + &dd_idx, &pd_idx, conf); + if (last_sector >= (mddev->size<<1)) + last_sector = (mddev->size<<1)-1; + while (first_sector <= last_sector) { + pd_idx = stripe_to_pdidx(first_sector, conf, + conf->previous_raid_disks); + sh = get_active_stripe(conf, first_sector, + conf->previous_raid_disks, pd_idx, 0); + set_bit(STRIPE_EXPAND_SOURCE, &sh->state); + set_bit(STRIPE_HANDLE, &sh->state); + release_stripe(sh); + first_sector += STRIPE_SECTORS; + } + /* If this takes us to the resync_max point where we have to pause, + * then we need to write out the superblock. + */ + sector_nr += conf->chunk_size>>9; + 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->expand_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->expand_lo = mddev->reshape_position; + spin_unlock_irq(&conf->device_lock); + wake_up(&conf->wait_for_overlap); + } + return conf->chunk_size>>9; +} + +/* 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; + int pd_idx; + int raid_disks = conf->raid_disks; + sector_t max_sector = mddev->size << 1; + 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->size << 1) - 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); + + pd_idx = stripe_to_pdidx(sector_nr, conf, raid_disks); + sh = get_active_stripe(conf, sector_nr, raid_disks, pd_idx, 1); + if (sh == NULL) { + sh = get_active_stripe(conf, sector_nr, raid_disks, pd_idx, 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; i<mddev->raid_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, pd_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( logical_sector, + conf->raid_disks, + conf->raid_disks - conf->max_degraded, + &dd_idx, + &pd_idx, + conf); + 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, conf->raid_disks, pd_idx, 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 int run(mddev_t *mddev) +{ + raid5_conf_t *conf; + int raid_disk, memory; + mdk_rdev_t *rdev; + struct disk_info *disk; + struct list_head *tmp; + int working_disks = 0; + + if (mddev->level != 5 && mddev->level != 4 && mddev->level != 6) { + printk(KERN_ERR "raid5: %s: raid level not set to 4/5/6 (%d)\n", + mdname(mddev), mddev->level); + return -EIO; + } + + if (mddev->chunk_size < PAGE_SIZE) { + printk(KERN_ERR "md/raid5: chunk_size must be at least " + "PAGE_SIZE but %d < %ld\n", + mddev->chunk_size, PAGE_SIZE); + return -EINVAL; + } + + 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 == 5 ? 1 : 2); + + if (mddev->new_level != mddev->level || + mddev->new_layout != mddev->layout || + mddev->new_chunk != mddev->chunk_size) { + printk(KERN_ERR "raid5: %s: unsupported reshape " + "required - aborting.\n", + mdname(mddev)); + return -EINVAL; + } + if (mddev->delta_disks <= 0) { + printk(KERN_ERR "raid5: %s: unsupported reshape " + "(reduce disks) 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->chunk_size>>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; */ + } + + + mddev->private = kzalloc(sizeof (raid5_conf_t), GFP_KERNEL); + if ((conf = mddev->private) == NULL) + goto abort; + if (mddev->reshape_position == MaxSector) { + conf->previous_raid_disks = conf->raid_disks = mddev->raid_disks; + } else { + conf->raid_disks = mddev->raid_disks; + 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->level == 6) { + conf->spare_page = alloc_page(GFP_KERNEL); + if (!conf->spare_page) + goto abort; + } + spin_lock_init(&conf->device_lock); + mddev->queue->queue_lock = &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)); + + rdev_for_each(rdev, tmp, mddev) { + 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); + working_disks++; + } else + /* Cannot rely on bitmap to complete recovery */ + conf->fullsync = 1; + } + + /* + * 0 for a fully functional array, 1 or 2 for a degraded array. + */ + mddev->degraded = conf->raid_disks - working_disks; + conf->mddev = mddev; + conf->chunk_size = mddev->chunk_size; + conf->level = mddev->level; + if (conf->level == 6) + conf->max_degraded = 2; + else + conf->max_degraded = 1; + conf->algorithm = mddev->layout; + conf->max_nr_stripes = NR_STRIPES; + conf->expand_progress = mddev->reshape_position; + + /* device size must be a multiple of chunk size */ + mddev->size &= ~(mddev->chunk_size/1024 -1); + mddev->resync_max_sectors = mddev->size << 1; + + if (conf->level == 6 && conf->raid_disks < 4) { + printk(KERN_ERR "raid6: not enough configured devices for %s (%d, minimum 4)\n", + mdname(mddev), conf->raid_disks); + goto abort; + } + if (!conf->chunk_size || conf->chunk_size % 4) { + printk(KERN_ERR "raid5: invalid chunk size %d for %s\n", + conf->chunk_size, mdname(mddev)); + goto abort; + } + if (conf->algorithm > ALGORITHM_RIGHT_SYMMETRIC) { + printk(KERN_ERR + "raid5: unsupported parity algorithm %d for %s\n", + conf->algorithm, mdname(mddev)); + goto abort; + } + 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; + } + + 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; + } + } + + { + mddev->thread = md_register_thread(raid5d, mddev, "%s_raid5"); + if (!mddev->thread) { + printk(KERN_ERR + "raid5: couldn't allocate thread for %s\n", + mdname(mddev)); + goto abort; + } + } + 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); + shrink_stripes(conf); + md_unregister_thread(mddev->thread); + goto abort; + } else + printk(KERN_INFO "raid5: allocated %dkB for %s\n", + memory, mdname(mddev)); + + 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, + conf->algorithm); + 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, conf->algorithm); + + print_raid5_conf(conf); + + if (conf->expand_progress != MaxSector) { + printk("...ok start reshape thread\n"); + conf->expand_lo = conf->expand_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->unplug_fn = raid5_unplug_device; + mddev->queue->backing_dev_info.congested_data = mddev; + mddev->queue->backing_dev_info.congested_fn = raid5_congested; + + mddev->array_sectors = 2 * mddev->size * (conf->previous_raid_disks - + conf->max_degraded); + + blk_queue_merge_bvec(mddev->queue, raid5_mergeable_bvec); + + return 0; +abort: + if (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 (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) { + 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. + */ + raid5_conf_t *conf = mddev_to_conf(mddev); + + sectors &= ~((sector_t)mddev->chunk_size/512 - 1); + mddev->array_sectors = sectors * (mddev->raid_disks + - conf->max_degraded); + set_capacity(mddev->gendisk, mddev->array_sectors); + mddev->changed = 1; + if (sectors/2 > mddev->size && mddev->recovery_cp == MaxSector) { + mddev->recovery_cp = mddev->size << 1; + set_bit(MD_RECOVERY_NEEDED, &mddev->recovery); + } + mddev->size = sectors /2; + mddev->resync_max_sectors = sectors; + return 0; +} + +#ifdef CONFIG_MD_RAID5_RESHAPE +static int raid5_check_reshape(mddev_t *mddev) +{ + raid5_conf_t *conf = mddev_to_conf(mddev); + int err; + + if (mddev->delta_disks < 0 || + mddev->new_level != mddev->level) + return -EINVAL; /* Cannot shrink array or change level yet */ + if (mddev->delta_disks == 0) + return 0; /* nothing to do */ + if (mddev->bitmap) + /* Cannot grow a bitmap yet */ + return -EBUSY; + + /* 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", + (mddev->chunk_size / STRIPE_SIZE)*4); + return -ENOSPC; + } + + err = resize_stripes(conf, conf->raid_disks + mddev->delta_disks); + if (err) + return err; + + if (mddev->degraded > conf->max_degraded) + return -EINVAL; + /* looks like we might be able to manage this */ + return 0; +} + +static int raid5_start_reshape(mddev_t *mddev) +{ + raid5_conf_t *conf = mddev_to_conf(mddev); + mdk_rdev_t *rdev; + struct list_head *rtmp; + int spares = 0; + int added_devices = 0; + unsigned long flags; + + if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery)) + return -EBUSY; + + rdev_for_each(rdev, rtmp, mddev) + 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; + + 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->expand_progress = 0; + conf->expand_lo = 0; + 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. + */ + rdev_for_each(rdev, rtmp, mddev) + 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; + } + + 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->expand_progress = MaxSector; + spin_unlock_irq(&conf->device_lock); + return -EAGAIN; + } + md_wakeup_thread(mddev->sync_thread); + md_new_event(mddev); + return 0; +} +#endif + +static void end_reshape(raid5_conf_t *conf) +{ + struct block_device *bdev; + + if (!test_bit(MD_RECOVERY_INTR, &conf->mddev->recovery)) { + conf->mddev->array_sectors = 2 * conf->mddev->size * + (conf->raid_disks - conf->max_degraded); + set_capacity(conf->mddev->gendisk, conf->mddev->array_sectors); + conf->mddev->changed = 1; + + bdev = bdget_disk(conf->mddev->gendisk, 0); + if (bdev) { + mutex_lock(&bdev->bd_inode->i_mutex); + i_size_write(bdev->bd_inode, + (loff_t)conf->mddev->array_sectors << 9); + mutex_unlock(&bdev->bd_inode->i_mutex); + bdput(bdev); + } + spin_lock_irq(&conf->device_lock); + conf->expand_progress = MaxSector; + spin_unlock_irq(&conf->device_lock); + conf->mddev->reshape_position = MaxSector; + + /* 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 * + (conf->mddev->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; + } + } +} + +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 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, +#ifdef CONFIG_MD_RAID5_RESHAPE + .check_reshape = raid5_check_reshape, + .start_reshape = raid5_start_reshape, +#endif + .quiesce = raid5_quiesce, +}; +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, +#ifdef CONFIG_MD_RAID5_RESHAPE + .check_reshape = raid5_check_reshape, + .start_reshape = raid5_start_reshape, +#endif + .quiesce = raid5_quiesce, +}; + +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, +#ifdef CONFIG_MD_RAID5_RESHAPE + .check_reshape = raid5_check_reshape, + .start_reshape = raid5_start_reshape, +#endif + .quiesce = raid5_quiesce, +}; + +static int __init raid5_init(void) +{ + int e; + + e = raid6_select_algo(); + if ( e ) + return e; + 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"); |
