--- /dev/null
+/*
+ * 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->seq_write is the number of the last batch successfully written.
+ * conf->seq_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 seq_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/blkdev.h>
+#include <linux/kthread.h>
+#include <linux/raid/pq.h>
+#include <linux/async_tx.h>
+#include <linux/module.h>
+#include <linux/async.h>
+#include <linux/seq_file.h>
+#include <linux/cpu.h>
+#include <linux/slab.h>
+#include <linux/ratelimit.h>
+#include <linux/nodemask.h>
+#include <linux/flex_array.h>
+#include <trace/events/block.h>
+
+#include "md.h"
+#include "raid5.h"
+#include "raid0.h"
+#include "bitmap.h"
+
+#define cpu_to_group(cpu) cpu_to_node(cpu)
+#define ANY_GROUP NUMA_NO_NODE
+
+static bool devices_handle_discard_safely = false;
+module_param(devices_handle_discard_safely, bool, 0644);
+MODULE_PARM_DESC(devices_handle_discard_safely,
+ "Set to Y if all devices in each array reliably return zeroes on reads from discarded regions");
+static struct workqueue_struct *raid5_wq;
+/*
+ * 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 MAX_STRIPE_BATCH 8
+
+static inline struct hlist_head *stripe_hash(struct r5conf *conf, sector_t sect)
+{
+ int hash = (sect >> STRIPE_SHIFT) & HASH_MASK;
+ return &conf->stripe_hashtbl[hash];
+}
+
+static inline int stripe_hash_locks_hash(sector_t sect)
+{
+ return (sect >> STRIPE_SHIFT) & STRIPE_HASH_LOCKS_MASK;
+}
+
+static inline void lock_device_hash_lock(struct r5conf *conf, int hash)
+{
+ spin_lock_irq(conf->hash_locks + hash);
+ spin_lock(&conf->device_lock);
+}
+
+static inline void unlock_device_hash_lock(struct r5conf *conf, int hash)
+{
+ spin_unlock(&conf->device_lock);
+ spin_unlock_irq(conf->hash_locks + hash);
+}
+
+static inline void lock_all_device_hash_locks_irq(struct r5conf *conf)
+{
+ int i;
+ local_irq_disable();
+ spin_lock(conf->hash_locks);
+ for (i = 1; i < NR_STRIPE_HASH_LOCKS; i++)
+ spin_lock_nest_lock(conf->hash_locks + i, conf->hash_locks);
+ spin_lock(&conf->device_lock);
+}
+
+static inline void unlock_all_device_hash_locks_irq(struct r5conf *conf)
+{
+ int i;
+ spin_unlock(&conf->device_lock);
+ for (i = NR_STRIPE_HASH_LOCKS; i; i--)
+ spin_unlock(conf->hash_locks + i - 1);
+ local_irq_enable();
+}
+
+/* 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 function is used to determine the 'next' bio in the list, given the sector
+ * of the current stripe+device
+ */
+static inline struct bio *r5_next_bio(struct bio *bio, sector_t sector)
+{
+ int sectors = bio_sectors(bio);
+ if (bio->bi_iter.bi_sector + sectors < sector + STRIPE_SECTORS)
+ return bio->bi_next;
+ else
+ return NULL;
+}
+
+/*
+ * 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_processed_stripes(struct bio *bio)
+{
+ atomic_t *segments = (atomic_t *)&bio->bi_phys_segments;
+ return (atomic_read(segments) >> 16) & 0xffff;
+}
+
+static inline int raid5_dec_bi_active_stripes(struct bio *bio)
+{
+ atomic_t *segments = (atomic_t *)&bio->bi_phys_segments;
+ return atomic_sub_return(1, segments) & 0xffff;
+}
+
+static inline void raid5_inc_bi_active_stripes(struct bio *bio)
+{
+ atomic_t *segments = (atomic_t *)&bio->bi_phys_segments;
+ atomic_inc(segments);
+}
+
+static inline void raid5_set_bi_processed_stripes(struct bio *bio,
+ unsigned int cnt)
+{
+ atomic_t *segments = (atomic_t *)&bio->bi_phys_segments;
+ int old, new;
+
+ do {
+ old = atomic_read(segments);
+ new = (old & 0xffff) | (cnt << 16);
+ } while (atomic_cmpxchg(segments, old, new) != old);
+}
+
+static inline void raid5_set_bi_stripes(struct bio *bio, unsigned int cnt)
+{
+ atomic_t *segments = (atomic_t *)&bio->bi_phys_segments;
+ atomic_set(segments, cnt);
+}
+
+/* Find first data disk in a raid6 stripe */
+static inline int raid6_d0(struct stripe_head *sh)
+{
+ if (sh->ddf_layout)
+ /* ddf always start from first device */
+ return 0;
+ /* md starts just after Q block */
+ if (sh->qd_idx == sh->disks - 1)
+ return 0;
+ else
+ return sh->qd_idx + 1;
+}
+static inline int raid6_next_disk(int disk, int raid_disks)
+{
+ disk++;
+ return (disk < raid_disks) ? disk : 0;
+}
+
+/* When walking through the disks in a raid5, starting at raid6_d0,
+ * We need to map each disk to a 'slot', where the data disks are slot
+ * 0 .. raid_disks-3, the parity disk is raid_disks-2 and the Q disk
+ * is raid_disks-1. This help does that mapping.
+ */
+static int raid6_idx_to_slot(int idx, struct stripe_head *sh,
+ int *count, int syndrome_disks)
+{
+ int slot = *count;
+
+ if (sh->ddf_layout)
+ (*count)++;
+ if (idx == sh->pd_idx)
+ return syndrome_disks;
+ if (idx == sh->qd_idx)
+ return syndrome_disks + 1;
+ if (!sh->ddf_layout)
+ (*count)++;
+ return slot;
+}
+
+static void return_io(struct bio *return_bi)
+{
+ struct bio *bi = return_bi;
+ while (bi) {
+
+ return_bi = bi->bi_next;
+ bi->bi_next = NULL;
+ bi->bi_iter.bi_size = 0;
+ trace_block_bio_complete(bdev_get_queue(bi->bi_bdev),
+ bi, 0);
+ bio_endio(bi, 0);
+ bi = return_bi;
+ }
+}
+
+static void print_raid5_conf (struct r5conf *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 raid5_wakeup_stripe_thread(struct stripe_head *sh)
+{
+ struct r5conf *conf = sh->raid_conf;
+ struct r5worker_group *group;
+ int thread_cnt;
+ int i, cpu = sh->cpu;
+
+ if (!cpu_online(cpu)) {
+ cpu = cpumask_any(cpu_online_mask);
+ sh->cpu = cpu;
+ }
+
+ if (list_empty(&sh->lru)) {
+ struct r5worker_group *group;
+ group = conf->worker_groups + cpu_to_group(cpu);
+ list_add_tail(&sh->lru, &group->handle_list);
+ group->stripes_cnt++;
+ sh->group = group;
+ }
+
+ if (conf->worker_cnt_per_group == 0) {
+ md_wakeup_thread(conf->mddev->thread);
+ return;
+ }
+
+ group = conf->worker_groups + cpu_to_group(sh->cpu);
+
+ group->workers[0].working = true;
+ /* at least one worker should run to avoid race */
+ queue_work_on(sh->cpu, raid5_wq, &group->workers[0].work);
+
+ thread_cnt = group->stripes_cnt / MAX_STRIPE_BATCH - 1;
+ /* wakeup more workers */
+ for (i = 1; i < conf->worker_cnt_per_group && thread_cnt > 0; i++) {
+ if (group->workers[i].working == false) {
+ group->workers[i].working = true;
+ queue_work_on(sh->cpu, raid5_wq,
+ &group->workers[i].work);
+ thread_cnt--;
+ }
+ }
+}
+
+static void do_release_stripe(struct r5conf *conf, struct stripe_head *sh,
+ struct list_head *temp_inactive_list)
+{
+ 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) &&
+ !test_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
+ list_add_tail(&sh->lru, &conf->delayed_list);
+ else if (test_bit(STRIPE_BIT_DELAY, &sh->state) &&
+ sh->bm_seq - conf->seq_write > 0)
+ list_add_tail(&sh->lru, &conf->bitmap_list);
+ else {
+ clear_bit(STRIPE_DELAYED, &sh->state);
+ clear_bit(STRIPE_BIT_DELAY, &sh->state);
+ if (conf->worker_cnt_per_group == 0) {
+ list_add_tail(&sh->lru, &conf->handle_list);
+ } else {
+ raid5_wakeup_stripe_thread(sh);
+ return;
+ }
+ }
+ md_wakeup_thread(conf->mddev->thread);
+ } else {
+ BUG_ON(stripe_operations_active(sh));
+ if (test_and_clear_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
+ if (atomic_dec_return(&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, temp_inactive_list);
+ }
+}
+
+static void __release_stripe(struct r5conf *conf, struct stripe_head *sh,
+ struct list_head *temp_inactive_list)
+{
+ if (atomic_dec_and_test(&sh->count))
+ do_release_stripe(conf, sh, temp_inactive_list);
+}
+
+/*
+ * @hash could be NR_STRIPE_HASH_LOCKS, then we have a list of inactive_list
+ *
+ * Be careful: Only one task can add/delete stripes from temp_inactive_list at
+ * given time. Adding stripes only takes device lock, while deleting stripes
+ * only takes hash lock.
+ */
+static void release_inactive_stripe_list(struct r5conf *conf,
+ struct list_head *temp_inactive_list,
+ int hash)
+{
+ int size;
+ bool do_wakeup = false;
+ unsigned long flags;
+
+ if (hash == NR_STRIPE_HASH_LOCKS) {
+ size = NR_STRIPE_HASH_LOCKS;
+ hash = NR_STRIPE_HASH_LOCKS - 1;
+ } else
+ size = 1;
+ while (size) {
+ struct list_head *list = &temp_inactive_list[size - 1];
+
+ /*
+ * We don't hold any lock here yet, get_active_stripe() might
+ * remove stripes from the list
+ */
+ if (!list_empty_careful(list)) {
+ spin_lock_irqsave(conf->hash_locks + hash, flags);
+ if (list_empty(conf->inactive_list + hash) &&
+ !list_empty(list))
+ atomic_dec(&conf->empty_inactive_list_nr);
+ list_splice_tail_init(list, conf->inactive_list + hash);
+ do_wakeup = true;
+ spin_unlock_irqrestore(conf->hash_locks + hash, flags);
+ }
+ size--;
+ hash--;
+ }
+
+ if (do_wakeup) {
+ wake_up(&conf->wait_for_stripe);
+ if (conf->retry_read_aligned)
+ md_wakeup_thread(conf->mddev->thread);
+ }
+}
+
+/* should hold conf->device_lock already */
+static int release_stripe_list(struct r5conf *conf,
+ struct list_head *temp_inactive_list)
+{
+ struct stripe_head *sh;
+ int count = 0;
+ struct llist_node *head;
+
+ head = llist_del_all(&conf->released_stripes);
+ head = llist_reverse_order(head);
+ while (head) {
+ int hash;
+
+ sh = llist_entry(head, struct stripe_head, release_list);
+ head = llist_next(head);
+ /* sh could be readded after STRIPE_ON_RELEASE_LIST is cleard */
+ smp_mb();
+ clear_bit(STRIPE_ON_RELEASE_LIST, &sh->state);
+ /*
+ * Don't worry the bit is set here, because if the bit is set
+ * again, the count is always > 1. This is true for
+ * STRIPE_ON_UNPLUG_LIST bit too.
+ */
+ hash = sh->hash_lock_index;
+ __release_stripe(conf, sh, &temp_inactive_list[hash]);
+ count++;
+ }
+
+ return count;
+}
+
+static void release_stripe(struct stripe_head *sh)
+{
+ struct r5conf *conf = sh->raid_conf;
+ unsigned long flags;
+ struct list_head list;
+ int hash;
+ bool wakeup;
+
+ /* Avoid release_list until the last reference.
+ */
+ if (atomic_add_unless(&sh->count, -1, 1))
+ return;
+
+ if (unlikely(!conf->mddev->thread) ||
+ test_and_set_bit(STRIPE_ON_RELEASE_LIST, &sh->state))
+ goto slow_path;
+ wakeup = llist_add(&sh->release_list, &conf->released_stripes);
+ if (wakeup)
+ md_wakeup_thread(conf->mddev->thread);
+ return;
+slow_path:
+ local_irq_save(flags);
+ /* we are ok here if STRIPE_ON_RELEASE_LIST is set or not */
+ if (atomic_dec_and_lock(&sh->count, &conf->device_lock)) {
+ INIT_LIST_HEAD(&list);
+ hash = sh->hash_lock_index;
+ do_release_stripe(conf, sh, &list);
+ spin_unlock(&conf->device_lock);
+ release_inactive_stripe_list(conf, &list, hash);
+ }
+ local_irq_restore(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(struct r5conf *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);
+
+ 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(struct r5conf *conf, int hash)
+{
+ struct stripe_head *sh = NULL;
+ struct list_head *first;
+
+ if (list_empty(conf->inactive_list + hash))
+ goto out;
+ first = (conf->inactive_list + hash)->next;
+ sh = list_entry(first, struct stripe_head, lru);
+ list_del_init(first);
+ remove_hash(sh);
+ atomic_inc(&conf->active_stripes);
+ BUG_ON(hash != sh->hash_lock_index);
+ if (list_empty(conf->inactive_list + hash))
+ atomic_inc(&conf->empty_inactive_list_nr);
+out:
+ return sh;
+}
+
+static void shrink_buffers(struct stripe_head *sh)
+{
+ struct page *p;
+ int i;
+ int num = sh->raid_conf->pool_size;
+
+ for (i = 0; i < num ; i++) {
+ WARN_ON(sh->dev[i].page != sh->dev[i].orig_page);
+ p = sh->dev[i].page;
+ if (!p)
+ continue;
+ sh->dev[i].page = NULL;
+ put_page(p);
+ }
+}
+
+static int grow_buffers(struct stripe_head *sh, gfp_t gfp)
+{
+ int i;
+ int num = sh->raid_conf->pool_size;
+
+ for (i = 0; i < num; i++) {
+ struct page *page;
+
+ if (!(page = alloc_page(gfp))) {
+ return 1;
+ }
+ sh->dev[i].page = page;
+ sh->dev[i].orig_page = page;
+ }
+ return 0;
+}
+
+static void raid5_build_block(struct stripe_head *sh, int i, int previous);
+static void stripe_set_idx(sector_t stripe, struct r5conf *conf, int previous,
+ struct stripe_head *sh);
+
+static void init_stripe(struct stripe_head *sh, sector_t sector, int previous)
+{
+ struct r5conf *conf = sh->raid_conf;
+ int i, seq;
+
+ BUG_ON(atomic_read(&sh->count) != 0);
+ BUG_ON(test_bit(STRIPE_HANDLE, &sh->state));
+ BUG_ON(stripe_operations_active(sh));
+ BUG_ON(sh->batch_head);
+
+ pr_debug("init_stripe called, stripe %llu\n",
+ (unsigned long long)sector);
+retry:
+ seq = read_seqcount_begin(&conf->gen_lock);
+ sh->generation = conf->generation - previous;
+ sh->disks = previous ? conf->previous_raid_disks : conf->raid_disks;
+ sh->sector = sector;
+ stripe_set_idx(sector, conf, previous, sh);
+ sh->state = 0;
+
+ for (i = sh->disks; i--; ) {
+ struct r5dev *dev = &sh->dev[i];
+
+ if (dev->toread || dev->read || dev->towrite || dev->written ||
+ test_bit(R5_LOCKED, &dev->flags)) {
+ printk(KERN_ERR "sector=%llx i=%d %p %p %p %p %d\n",
+ (unsigned long long)sh->sector, i, dev->toread,
+ dev->read, dev->towrite, dev->written,
+ test_bit(R5_LOCKED, &dev->flags));
+ WARN_ON(1);
+ }
+ dev->flags = 0;
+ raid5_build_block(sh, i, previous);
+ }
+ if (read_seqcount_retry(&conf->gen_lock, seq))
+ goto retry;
+ sh->overwrite_disks = 0;
+ insert_hash(conf, sh);
+ sh->cpu = smp_processor_id();
+ set_bit(STRIPE_BATCH_READY, &sh->state);
+}
+
+static struct stripe_head *__find_stripe(struct r5conf *conf, sector_t sector,
+ short generation)
+{
+ struct stripe_head *sh;
+
+ pr_debug("__find_stripe, sector %llu\n", (unsigned long long)sector);
+ hlist_for_each_entry(sh, stripe_hash(conf, sector), hash)
+ if (sh->sector == sector && sh->generation == generation)
+ return sh;
+ pr_debug("__stripe %llu not in cache\n", (unsigned long long)sector);
+ return NULL;
+}
+
+/*
+ * Need to check if array has failed when deciding whether to:
+ * - start an array
+ * - remove non-faulty devices
+ * - add a spare
+ * - allow a reshape
+ * This determination is simple when no reshape is happening.
+ * However if there is a reshape, we need to carefully check
+ * both the before and after sections.
+ * This is because some failed devices may only affect one
+ * of the two sections, and some non-in_sync devices may
+ * be insync in the section most affected by failed devices.
+ */
+static int calc_degraded(struct r5conf *conf)
+{
+ int degraded, degraded2;
+ int i;
+
+ rcu_read_lock();
+ degraded = 0;
+ for (i = 0; i < conf->previous_raid_disks; i++) {
+ struct md_rdev *rdev = rcu_dereference(conf->disks[i].rdev);
+ if (rdev && test_bit(Faulty, &rdev->flags))
+ rdev = rcu_dereference(conf->disks[i].replacement);
+ if (!rdev || test_bit(Faulty, &rdev->flags))
+ degraded++;
+ else if (test_bit(In_sync, &rdev->flags))
+ ;
+ else
+ /* not in-sync or faulty.
+ * If the reshape increases the number of devices,
+ * this is being recovered by the reshape, so
+ * this 'previous' section is not in_sync.
+ * If the number of devices is being reduced however,
+ * the device can only be part of the array if
+ * we are reverting a reshape, so this section will
+ * be in-sync.
+ */
+ if (conf->raid_disks >= conf->previous_raid_disks)
+ degraded++;
+ }
+ rcu_read_unlock();
+ if (conf->raid_disks == conf->previous_raid_disks)
+ return degraded;
+ rcu_read_lock();
+ degraded2 = 0;
+ for (i = 0; i < conf->raid_disks; i++) {
+ struct md_rdev *rdev = rcu_dereference(conf->disks[i].rdev);
+ if (rdev && test_bit(Faulty, &rdev->flags))
+ rdev = rcu_dereference(conf->disks[i].replacement);
+ if (!rdev || test_bit(Faulty, &rdev->flags))
+ degraded2++;
+ else if (test_bit(In_sync, &rdev->flags))
+ ;
+ else
+ /* not in-sync or faulty.
+ * If reshape increases the number of devices, this
+ * section has already been recovered, else it
+ * almost certainly hasn't.
+ */
+ if (conf->raid_disks <= conf->previous_raid_disks)
+ degraded2++;
+ }
+ rcu_read_unlock();
+ if (degraded2 > degraded)
+ return degraded2;
+ return degraded;
+}
+
+static int has_failed(struct r5conf *conf)
+{
+ int degraded;
+
+ if (conf->mddev->reshape_position == MaxSector)
+ return conf->mddev->degraded > conf->max_degraded;
+
+ degraded = calc_degraded(conf);
+ if (degraded > conf->max_degraded)
+ return 1;
+ return 0;
+}
+
+static struct stripe_head *
+get_active_stripe(struct r5conf *conf, sector_t sector,
+ int previous, int noblock, int noquiesce)
+{
+ struct stripe_head *sh;
+ int hash = stripe_hash_locks_hash(sector);
+
+ pr_debug("get_stripe, sector %llu\n", (unsigned long long)sector);
+
+ spin_lock_irq(conf->hash_locks + hash);
+
+ do {
+ wait_event_lock_irq(conf->wait_for_stripe,
+ conf->quiesce == 0 || noquiesce,
+ *(conf->hash_locks + hash));
+ sh = __find_stripe(conf, sector, conf->generation - previous);
+ if (!sh) {
+ if (!test_bit(R5_INACTIVE_BLOCKED, &conf->cache_state)) {
+ sh = get_free_stripe(conf, hash);
+ if (!sh && llist_empty(&conf->released_stripes) &&
+ !test_bit(R5_DID_ALLOC, &conf->cache_state))
+ set_bit(R5_ALLOC_MORE,
+ &conf->cache_state);
+ }
+ if (noblock && sh == NULL)
+ break;
+ if (!sh) {
+ set_bit(R5_INACTIVE_BLOCKED,
+ &conf->cache_state);
+ wait_event_lock_irq(
+ conf->wait_for_stripe,
+ !list_empty(conf->inactive_list + hash) &&
+ (atomic_read(&conf->active_stripes)
+ < (conf->max_nr_stripes * 3 / 4)
+ || !test_bit(R5_INACTIVE_BLOCKED,
+ &conf->cache_state)),
+ *(conf->hash_locks + hash));
+ clear_bit(R5_INACTIVE_BLOCKED,
+ &conf->cache_state);
+ } else {
+ init_stripe(sh, sector, previous);
+ atomic_inc(&sh->count);
+ }
+ } else if (!atomic_inc_not_zero(&sh->count)) {
+ spin_lock(&conf->device_lock);
+ if (!atomic_read(&sh->count)) {
+ if (!test_bit(STRIPE_HANDLE, &sh->state))
+ atomic_inc(&conf->active_stripes);
+ BUG_ON(list_empty(&sh->lru) &&
+ !test_bit(STRIPE_EXPANDING, &sh->state));
+ list_del_init(&sh->lru);
+ if (sh->group) {
+ sh->group->stripes_cnt--;
+ sh->group = NULL;
+ }
+ }
+ atomic_inc(&sh->count);
+ spin_unlock(&conf->device_lock);
+ }
+ } while (sh == NULL);
+
+ spin_unlock_irq(conf->hash_locks + hash);
+ return sh;
+}
+
+static bool is_full_stripe_write(struct stripe_head *sh)
+{
+ BUG_ON(sh->overwrite_disks > (sh->disks - sh->raid_conf->max_degraded));
+ return sh->overwrite_disks == (sh->disks - sh->raid_conf->max_degraded);
+}
+
+static void lock_two_stripes(struct stripe_head *sh1, struct stripe_head *sh2)
+{
+ local_irq_disable();
+ if (sh1 > sh2) {
+ spin_lock(&sh2->stripe_lock);
+ spin_lock_nested(&sh1->stripe_lock, 1);
+ } else {
+ spin_lock(&sh1->stripe_lock);
+ spin_lock_nested(&sh2->stripe_lock, 1);
+ }
+}
+
+static void unlock_two_stripes(struct stripe_head *sh1, struct stripe_head *sh2)
+{
+ spin_unlock(&sh1->stripe_lock);
+ spin_unlock(&sh2->stripe_lock);
+ local_irq_enable();
+}
+
+/* Only freshly new full stripe normal write stripe can be added to a batch list */
+static bool stripe_can_batch(struct stripe_head *sh)
+{
+ return test_bit(STRIPE_BATCH_READY, &sh->state) &&
+ !test_bit(STRIPE_BITMAP_PENDING, &sh->state) &&
+ is_full_stripe_write(sh);
+}
+
+/* we only do back search */
+static void stripe_add_to_batch_list(struct r5conf *conf, struct stripe_head *sh)
+{
+ struct stripe_head *head;
+ sector_t head_sector, tmp_sec;
+ int hash;
+ int dd_idx;
+
+ if (!stripe_can_batch(sh))
+ return;
+ /* Don't cross chunks, so stripe pd_idx/qd_idx is the same */
+ tmp_sec = sh->sector;
+ if (!sector_div(tmp_sec, conf->chunk_sectors))
+ return;
+ head_sector = sh->sector - STRIPE_SECTORS;
+
+ hash = stripe_hash_locks_hash(head_sector);
+ spin_lock_irq(conf->hash_locks + hash);
+ head = __find_stripe(conf, head_sector, conf->generation);
+ if (head && !atomic_inc_not_zero(&head->count)) {
+ spin_lock(&conf->device_lock);
+ if (!atomic_read(&head->count)) {
+ if (!test_bit(STRIPE_HANDLE, &head->state))
+ atomic_inc(&conf->active_stripes);
+ BUG_ON(list_empty(&head->lru) &&
+ !test_bit(STRIPE_EXPANDING, &head->state));
+ list_del_init(&head->lru);
+ if (head->group) {
+ head->group->stripes_cnt--;
+ head->group = NULL;
+ }
+ }
+ atomic_inc(&head->count);
+ spin_unlock(&conf->device_lock);
+ }
+ spin_unlock_irq(conf->hash_locks + hash);
+
+ if (!head)
+ return;
+ if (!stripe_can_batch(head))
+ goto out;
+
+ lock_two_stripes(head, sh);
+ /* clear_batch_ready clear the flag */
+ if (!stripe_can_batch(head) || !stripe_can_batch(sh))
+ goto unlock_out;
+
+ if (sh->batch_head)
+ goto unlock_out;
+
+ dd_idx = 0;
+ while (dd_idx == sh->pd_idx || dd_idx == sh->qd_idx)
+ dd_idx++;
+ if (head->dev[dd_idx].towrite->bi_rw != sh->dev[dd_idx].towrite->bi_rw)
+ goto unlock_out;
+
+ if (head->batch_head) {
+ spin_lock(&head->batch_head->batch_lock);
+ /* This batch list is already running */
+ if (!stripe_can_batch(head)) {
+ spin_unlock(&head->batch_head->batch_lock);
+ goto unlock_out;
+ }
+
+ /*
+ * at this point, head's BATCH_READY could be cleared, but we
+ * can still add the stripe to batch list
+ */
+ list_add(&sh->batch_list, &head->batch_list);
+ spin_unlock(&head->batch_head->batch_lock);
+
+ sh->batch_head = head->batch_head;
+ } else {
+ head->batch_head = head;
+ sh->batch_head = head->batch_head;
+ spin_lock(&head->batch_lock);
+ list_add_tail(&sh->batch_list, &head->batch_list);
+ spin_unlock(&head->batch_lock);
+ }
+
+ if (test_and_clear_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
+ if (atomic_dec_return(&conf->preread_active_stripes)
+ < IO_THRESHOLD)
+ md_wakeup_thread(conf->mddev->thread);
+
+ if (test_and_clear_bit(STRIPE_BIT_DELAY, &sh->state)) {
+ int seq = sh->bm_seq;
+ if (test_bit(STRIPE_BIT_DELAY, &sh->batch_head->state) &&
+ sh->batch_head->bm_seq > seq)
+ seq = sh->batch_head->bm_seq;
+ set_bit(STRIPE_BIT_DELAY, &sh->batch_head->state);
+ sh->batch_head->bm_seq = seq;
+ }
+
+ atomic_inc(&sh->count);
+unlock_out:
+ unlock_two_stripes(head, sh);
+out:
+ release_stripe(head);
+}
+
+/* Determine if 'data_offset' or 'new_data_offset' should be used
+ * in this stripe_head.
+ */
+static int use_new_offset(struct r5conf *conf, struct stripe_head *sh)
+{
+ sector_t progress = conf->reshape_progress;
+ /* Need a memory barrier to make sure we see the value
+ * of conf->generation, or ->data_offset that was set before
+ * reshape_progress was updated.
+ */
+ smp_rmb();
+ if (progress == MaxSector)
+ return 0;
+ if (sh->generation == conf->generation - 1)
+ return 0;
+ /* We are in a reshape, and this is a new-generation stripe,
+ * so use new_data_offset.
+ */
+ return 1;
+}
+
+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)
+{
+ struct r5conf *conf = sh->raid_conf;
+ int i, disks = sh->disks;
+ struct stripe_head *head_sh = sh;
+
+ might_sleep();
+
+ for (i = disks; i--; ) {
+ int rw;
+ int replace_only = 0;
+ struct bio *bi, *rbi;
+ struct md_rdev *rdev, *rrdev = NULL;
+
+ sh = head_sh;
+ if (test_and_clear_bit(R5_Wantwrite, &sh->dev[i].flags)) {
+ if (test_and_clear_bit(R5_WantFUA, &sh->dev[i].flags))
+ rw = WRITE_FUA;
+ else
+ rw = WRITE;
+ if (test_bit(R5_Discard, &sh->dev[i].flags))
+ rw |= REQ_DISCARD;
+ } else if (test_and_clear_bit(R5_Wantread, &sh->dev[i].flags))
+ rw = READ;
+ else if (test_and_clear_bit(R5_WantReplace,
+ &sh->dev[i].flags)) {
+ rw = WRITE;
+ replace_only = 1;
+ } else
+ continue;
+ if (test_and_clear_bit(R5_SyncIO, &sh->dev[i].flags))
+ rw |= REQ_SYNC;
+
+again:
+ bi = &sh->dev[i].req;
+ rbi = &sh->dev[i].rreq; /* For writing to replacement */
+
+ rcu_read_lock();
+ rrdev = rcu_dereference(conf->disks[i].replacement);
+ smp_mb(); /* Ensure that if rrdev is NULL, rdev won't be */
+ rdev = rcu_dereference(conf->disks[i].rdev);
+ if (!rdev) {
+ rdev = rrdev;
+ rrdev = NULL;
+ }
+ if (rw & WRITE) {
+ if (replace_only)
+ rdev = NULL;
+ if (rdev == rrdev)
+ /* We raced and saw duplicates */
+ rrdev = NULL;
+ } else {
+ if (test_bit(R5_ReadRepl, &head_sh->dev[i].flags) && rrdev)
+ rdev = rrdev;
+ rrdev = NULL;
+ }
+
+ if (rdev && test_bit(Faulty, &rdev->flags))
+ rdev = NULL;
+ if (rdev)
+ atomic_inc(&rdev->nr_pending);
+ if (rrdev && test_bit(Faulty, &rrdev->flags))
+ rrdev = NULL;
+ if (rrdev)
+ atomic_inc(&rrdev->nr_pending);
+ rcu_read_unlock();
+
+ /* We have already checked bad blocks for reads. Now
+ * need to check for writes. We never accept write errors
+ * on the replacement, so we don't to check rrdev.
+ */
+ while ((rw & WRITE) && rdev &&
+ test_bit(WriteErrorSeen, &rdev->flags)) {
+ sector_t first_bad;
+ int bad_sectors;
+ int bad = is_badblock(rdev, sh->sector, STRIPE_SECTORS,
+ &first_bad, &bad_sectors);
+ if (!bad)
+ break;
+
+ if (bad < 0) {
+ set_bit(BlockedBadBlocks, &rdev->flags);
+ if (!conf->mddev->external &&
+ conf->mddev->flags) {
+ /* It is very unlikely, but we might
+ * still need to write out the
+ * bad block log - better give it
+ * a chance*/
+ md_check_recovery(conf->mddev);
+ }
+ /*
+ * Because md_wait_for_blocked_rdev
+ * will dec nr_pending, we must
+ * increment it first.
+ */
+ atomic_inc(&rdev->nr_pending);
+ md_wait_for_blocked_rdev(rdev, conf->mddev);
+ } else {
+ /* Acknowledged bad block - skip the write */
+ rdev_dec_pending(rdev, conf->mddev);
+ rdev = NULL;
+ }
+ }
+
+ if (rdev) {
+ if (s->syncing || s->expanding || s->expanded
+ || s->replacing)
+ md_sync_acct(rdev->bdev, STRIPE_SECTORS);
+
+ set_bit(STRIPE_IO_STARTED, &sh->state);
+
+ bio_reset(bi);
+ bi->bi_bdev = rdev->bdev;
+ bi->bi_rw = rw;
+ bi->bi_end_io = (rw & WRITE)
+ ? raid5_end_write_request
+ : raid5_end_read_request;
+ bi->bi_private = sh;
+
+ 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);
+ if (sh != head_sh)
+ atomic_inc(&head_sh->count);
+ if (use_new_offset(conf, sh))
+ bi->bi_iter.bi_sector = (sh->sector
+ + rdev->new_data_offset);
+ else
+ bi->bi_iter.bi_sector = (sh->sector
+ + rdev->data_offset);
+ if (test_bit(R5_ReadNoMerge, &head_sh->dev[i].flags))
+ bi->bi_rw |= REQ_NOMERGE;
+
+ if (test_bit(R5_SkipCopy, &sh->dev[i].flags))
+ WARN_ON(test_bit(R5_UPTODATE, &sh->dev[i].flags));
+ sh->dev[i].vec.bv_page = sh->dev[i].page;
+ bi->bi_vcnt = 1;
+ bi->bi_io_vec[0].bv_len = STRIPE_SIZE;
+ bi->bi_io_vec[0].bv_offset = 0;
+ bi->bi_iter.bi_size = STRIPE_SIZE;
+ /*
+ * If this is discard request, set bi_vcnt 0. We don't
+ * want to confuse SCSI because SCSI will replace payload
+ */
+ if (rw & REQ_DISCARD)
+ bi->bi_vcnt = 0;
+ if (rrdev)
+ set_bit(R5_DOUBLE_LOCKED, &sh->dev[i].flags);
+
+ if (conf->mddev->gendisk)
+ trace_block_bio_remap(bdev_get_queue(bi->bi_bdev),
+ bi, disk_devt(conf->mddev->gendisk),
+ sh->dev[i].sector);
+ generic_make_request(bi);
+ }
+ if (rrdev) {
+ if (s->syncing || s->expanding || s->expanded
+ || s->replacing)
+ md_sync_acct(rrdev->bdev, STRIPE_SECTORS);
+
+ set_bit(STRIPE_IO_STARTED, &sh->state);
+
+ bio_reset(rbi);
+ rbi->bi_bdev = rrdev->bdev;
+ rbi->bi_rw = rw;
+ BUG_ON(!(rw & WRITE));
+ rbi->bi_end_io = raid5_end_write_request;
+ rbi->bi_private = sh;
+
+ pr_debug("%s: for %llu schedule op %ld on "
+ "replacement disc %d\n",
+ __func__, (unsigned long long)sh->sector,
+ rbi->bi_rw, i);
+ atomic_inc(&sh->count);
+ if (sh != head_sh)
+ atomic_inc(&head_sh->count);
+ if (use_new_offset(conf, sh))
+ rbi->bi_iter.bi_sector = (sh->sector
+ + rrdev->new_data_offset);
+ else
+ rbi->bi_iter.bi_sector = (sh->sector
+ + rrdev->data_offset);
+ if (test_bit(R5_SkipCopy, &sh->dev[i].flags))
+ WARN_ON(test_bit(R5_UPTODATE, &sh->dev[i].flags));
+ sh->dev[i].rvec.bv_page = sh->dev[i].page;
+ rbi->bi_vcnt = 1;
+ rbi->bi_io_vec[0].bv_len = STRIPE_SIZE;
+ rbi->bi_io_vec[0].bv_offset = 0;
+ rbi->bi_iter.bi_size = STRIPE_SIZE;
+ /*
+ * If this is discard request, set bi_vcnt 0. We don't
+ * want to confuse SCSI because SCSI will replace payload
+ */
+ if (rw & REQ_DISCARD)
+ rbi->bi_vcnt = 0;
+ if (conf->mddev->gendisk)
+ trace_block_bio_remap(bdev_get_queue(rbi->bi_bdev),
+ rbi, disk_devt(conf->mddev->gendisk),
+ sh->dev[i].sector);
+ generic_make_request(rbi);
+ }
+ if (!rdev && !rrdev) {
+ 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);
+ }
+
+ if (!head_sh->batch_head)
+ continue;
+ sh = list_first_entry(&sh->batch_list, struct stripe_head,
+ batch_list);
+ if (sh != head_sh)
+ goto again;
+ }
+}
+
+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 stripe_head *sh)
+{
+ struct bio_vec bvl;
+ struct bvec_iter iter;
+ struct page *bio_page;
+ int page_offset;
+ struct async_submit_ctl submit;
+ enum async_tx_flags flags = 0;
+
+ if (bio->bi_iter.bi_sector >= sector)
+ page_offset = (signed)(bio->bi_iter.bi_sector - sector) * 512;
+ else
+ page_offset = (signed)(sector - bio->bi_iter.bi_sector) * -512;
+
+ if (frombio)
+ flags |= ASYNC_TX_FENCE;
+ init_async_submit(&submit, flags, tx, NULL, NULL, NULL);
+
+ bio_for_each_segment(bvl, bio, iter) {
+ int len = bvl.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 += bvl.bv_offset;
+ bio_page = bvl.bv_page;
+ if (frombio) {
+ if (sh->raid_conf->skip_copy &&
+ b_offset == 0 && page_offset == 0 &&
+ clen == STRIPE_SIZE)
+ *page = bio_page;
+ else
+ tx = async_memcpy(*page, bio_page, page_offset,
+ b_offset, clen, &submit);
+ } else
+ tx = async_memcpy(bio_page, *page, b_offset,
+ page_offset, clen, &submit);
+ }
+ /* chain the operations */
+ submit.depend_tx = tx;
+
+ 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;
+ int i;
+
+ pr_debug("%s: stripe %llu\n", __func__,
+ (unsigned long long)sh->sector);
+
+ /* clear completed biofills */
+ 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_iter.bi_sector <
+ dev->sector + STRIPE_SECTORS) {
+ rbi2 = r5_next_bio(rbi, dev->sector);
+ if (!raid5_dec_bi_active_stripes(rbi)) {
+ rbi->bi_next = return_bi;
+ return_bi = rbi;
+ }
+ rbi = rbi2;
+ }
+ }
+ }
+ 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;
+ struct async_submit_ctl submit;
+ int i;
+
+ BUG_ON(sh->batch_head);
+ 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(&sh->stripe_lock);
+ dev->read = rbi = dev->toread;
+ dev->toread = NULL;
+ spin_unlock_irq(&sh->stripe_lock);
+ while (rbi && rbi->bi_iter.bi_sector <
+ dev->sector + STRIPE_SECTORS) {
+ tx = async_copy_data(0, rbi, &dev->page,
+ dev->sector, tx, sh);
+ rbi = r5_next_bio(rbi, dev->sector);
+ }
+ }
+ }
+
+ atomic_inc(&sh->count);
+ init_async_submit(&submit, ASYNC_TX_ACK, tx, ops_complete_biofill, sh, NULL);
+ async_trigger_callback(&submit);
+}
+
+static void mark_target_uptodate(struct stripe_head *sh, int target)
+{
+ struct r5dev *tgt;
+
+ if (target < 0)
+ return;
+
+ tgt = &sh->dev[target];
+ set_bit(R5_UPTODATE, &tgt->flags);
+ BUG_ON(!test_bit(R5_Wantcompute, &tgt->flags));
+ clear_bit(R5_Wantcompute, &tgt->flags);
+}
+
+static void ops_complete_compute(void *stripe_head_ref)
+{
+ struct stripe_head *sh = stripe_head_ref;
+
+ pr_debug("%s: stripe %llu\n", __func__,
+ (unsigned long long)sh->sector);
+
+ /* mark the computed target(s) as uptodate */
+ mark_target_uptodate(sh, sh->ops.target);
+ mark_target_uptodate(sh, sh->ops.target2);
+
+ 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);
+}
+
+/* return a pointer to the address conversion region of the scribble buffer */
+static addr_conv_t *to_addr_conv(struct stripe_head *sh,
+ struct raid5_percpu *percpu, int i)
+{
+ void *addr;
+
+ addr = flex_array_get(percpu->scribble, i);
+ return addr + sizeof(struct page *) * (sh->disks + 2);
+}
+
+/* return a pointer to the address conversion region of the scribble buffer */
+static struct page **to_addr_page(struct raid5_percpu *percpu, int i)
+{
+ void *addr;
+
+ addr = flex_array_get(percpu->scribble, i);
+ return addr;
+}
+
+static struct dma_async_tx_descriptor *
+ops_run_compute5(struct stripe_head *sh, struct raid5_percpu *percpu)
+{
+ int disks = sh->disks;
+ struct page **xor_srcs = to_addr_page(percpu, 0);
+ 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;
+ struct async_submit_ctl submit;
+ int i;
+
+ BUG_ON(sh->batch_head);
+
+ 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);
+
+ init_async_submit(&submit, ASYNC_TX_FENCE|ASYNC_TX_XOR_ZERO_DST, NULL,
+ ops_complete_compute, sh, to_addr_conv(sh, percpu, 0));
+ if (unlikely(count == 1))
+ tx = async_memcpy(xor_dest, xor_srcs[0], 0, 0, STRIPE_SIZE, &submit);
+ else
+ tx = async_xor(xor_dest, xor_srcs, 0, count, STRIPE_SIZE, &submit);
+
+ return tx;
+}
+
+/* set_syndrome_sources - populate source buffers for gen_syndrome
+ * @srcs - (struct page *) array of size sh->disks
+ * @sh - stripe_head to parse
+ *
+ * Populates srcs in proper layout order for the stripe and returns the
+ * 'count' of sources to be used in a call to async_gen_syndrome. The P
+ * destination buffer is recorded in srcs[count] and the Q destination
+ * is recorded in srcs[count+1]].
+ */
+static int set_syndrome_sources(struct page **srcs,
+ struct stripe_head *sh,
+ int srctype)
+{
+ int disks = sh->disks;
+ int syndrome_disks = sh->ddf_layout ? disks : (disks - 2);
+ int d0_idx = raid6_d0(sh);
+ int count;
+ int i;
+
+ for (i = 0; i < disks; i++)
+ srcs[i] = NULL;
+
+ count = 0;
+ i = d0_idx;
+ do {
+ int slot = raid6_idx_to_slot(i, sh, &count, syndrome_disks);
+ struct r5dev *dev = &sh->dev[i];
+
+ if (i == sh->qd_idx || i == sh->pd_idx ||
+ (srctype == SYNDROME_SRC_ALL) ||
+ (srctype == SYNDROME_SRC_WANT_DRAIN &&
+ test_bit(R5_Wantdrain, &dev->flags)) ||
+ (srctype == SYNDROME_SRC_WRITTEN &&
+ dev->written))
+ srcs[slot] = sh->dev[i].page;
+ i = raid6_next_disk(i, disks);
+ } while (i != d0_idx);
+
+ return syndrome_disks;
+}
+
+static struct dma_async_tx_descriptor *
+ops_run_compute6_1(struct stripe_head *sh, struct raid5_percpu *percpu)
+{
+ int disks = sh->disks;
+ struct page **blocks = to_addr_page(percpu, 0);
+ int target;
+ int qd_idx = sh->qd_idx;
+ struct dma_async_tx_descriptor *tx;
+ struct async_submit_ctl submit;
+ struct r5dev *tgt;
+ struct page *dest;
+ int i;
+ int count;
+
+ BUG_ON(sh->batch_head);
+ if (sh->ops.target < 0)
+ target = sh->ops.target2;
+ else if (sh->ops.target2 < 0)
+ target = sh->ops.target;
+ else
+ /* we should only have one valid target */
+ BUG();
+ BUG_ON(target < 0);
+ pr_debug("%s: stripe %llu block: %d\n",
+ __func__, (unsigned long long)sh->sector, target);
+
+ tgt = &sh->dev[target];
+ BUG_ON(!test_bit(R5_Wantcompute, &tgt->flags));
+ dest = tgt->page;
+
+ atomic_inc(&sh->count);
+
+ if (target == qd_idx) {
+ count = set_syndrome_sources(blocks, sh, SYNDROME_SRC_ALL);
+ blocks[count] = NULL; /* regenerating p is not necessary */
+ BUG_ON(blocks[count+1] != dest); /* q should already be set */
+ init_async_submit(&submit, ASYNC_TX_FENCE, NULL,
+ ops_complete_compute, sh,
+ to_addr_conv(sh, percpu, 0));
+ tx = async_gen_syndrome(blocks, 0, count+2, STRIPE_SIZE, &submit);
+ } else {
+ /* Compute any data- or p-drive using XOR */
+ count = 0;
+ for (i = disks; i-- ; ) {
+ if (i == target || i == qd_idx)
+ continue;
+ blocks[count++] = sh->dev[i].page;
+ }
+
+ init_async_submit(&submit, ASYNC_TX_FENCE|ASYNC_TX_XOR_ZERO_DST,
+ NULL, ops_complete_compute, sh,
+ to_addr_conv(sh, percpu, 0));
+ tx = async_xor(dest, blocks, 0, count, STRIPE_SIZE, &submit);
+ }
+
+ return tx;
+}
+
+static struct dma_async_tx_descriptor *
+ops_run_compute6_2(struct stripe_head *sh, struct raid5_percpu *percpu)
+{
+ int i, count, disks = sh->disks;
+ int syndrome_disks = sh->ddf_layout ? disks : disks-2;
+ int d0_idx = raid6_d0(sh);
+ int faila = -1, failb = -1;
+ int target = sh->ops.target;
+ int target2 = sh->ops.target2;
+ struct r5dev *tgt = &sh->dev[target];
+ struct r5dev *tgt2 = &sh->dev[target2];
+ struct dma_async_tx_descriptor *tx;
+ struct page **blocks = to_addr_page(percpu, 0);
+ struct async_submit_ctl submit;
+
+ BUG_ON(sh->batch_head);
+ pr_debug("%s: stripe %llu block1: %d block2: %d\n",
+ __func__, (unsigned long long)sh->sector, target, target2);
+ BUG_ON(target < 0 || target2 < 0);
+ BUG_ON(!test_bit(R5_Wantcompute, &tgt->flags));
+ BUG_ON(!test_bit(R5_Wantcompute, &tgt2->flags));
+
+ /* we need to open-code set_syndrome_sources to handle the
+ * slot number conversion for 'faila' and 'failb'
+ */
+ for (i = 0; i < disks ; i++)
+ blocks[i] = NULL;
+ count = 0;
+ i = d0_idx;
+ do {
+ int slot = raid6_idx_to_slot(i, sh, &count, syndrome_disks);
+
+ blocks[slot] = sh->dev[i].page;
+
+ if (i == target)
+ faila = slot;
+ if (i == target2)
+ failb = slot;
+ i = raid6_next_disk(i, disks);
+ } while (i != d0_idx);
+
+ BUG_ON(faila == failb);
+ if (failb < faila)
+ swap(faila, failb);
+ pr_debug("%s: stripe: %llu faila: %d failb: %d\n",
+ __func__, (unsigned long long)sh->sector, faila, failb);
+
+ atomic_inc(&sh->count);
+
+ if (failb == syndrome_disks+1) {
+ /* Q disk is one of the missing disks */
+ if (faila == syndrome_disks) {
+ /* Missing P+Q, just recompute */
+ init_async_submit(&submit, ASYNC_TX_FENCE, NULL,
+ ops_complete_compute, sh,
+ to_addr_conv(sh, percpu, 0));
+ return async_gen_syndrome(blocks, 0, syndrome_disks+2,
+ STRIPE_SIZE, &submit);
+ } else {
+ struct page *dest;
+ int data_target;
+ int qd_idx = sh->qd_idx;
+
+ /* Missing D+Q: recompute D from P, then recompute Q */
+ if (target == qd_idx)
+ data_target = target2;
+ else
+ data_target = target;
+
+ count = 0;
+ for (i = disks; i-- ; ) {
+ if (i == data_target || i == qd_idx)
+ continue;
+ blocks[count++] = sh->dev[i].page;
+ }
+ dest = sh->dev[data_target].page;
+ init_async_submit(&submit,
+ ASYNC_TX_FENCE|ASYNC_TX_XOR_ZERO_DST,
+ NULL, NULL, NULL,
+ to_addr_conv(sh, percpu, 0));
+ tx = async_xor(dest, blocks, 0, count, STRIPE_SIZE,
+ &submit);
+
+ count = set_syndrome_sources(blocks, sh, SYNDROME_SRC_ALL);
+ init_async_submit(&submit, ASYNC_TX_FENCE, tx,
+ ops_complete_compute, sh,
+ to_addr_conv(sh, percpu, 0));
+ return async_gen_syndrome(blocks, 0, count+2,
+ STRIPE_SIZE, &submit);
+ }
+ } else {
+ init_async_submit(&submit, ASYNC_TX_FENCE, NULL,
+ ops_complete_compute, sh,
+ to_addr_conv(sh, percpu, 0));
+ if (failb == syndrome_disks) {
+ /* We're missing D+P. */
+ return async_raid6_datap_recov(syndrome_disks+2,
+ STRIPE_SIZE, faila,
+ blocks, &submit);
+ } else {
+ /* We're missing D+D. */
+ return async_raid6_2data_recov(syndrome_disks+2,
+ STRIPE_SIZE, faila, failb,
+ blocks, &submit);
+ }
+ }
+}
+
+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_prexor5(struct stripe_head *sh, struct raid5_percpu *percpu,
+ struct dma_async_tx_descriptor *tx)
+{
+ int disks = sh->disks;
+ struct page **xor_srcs = to_addr_page(percpu, 0);
+ int count = 0, pd_idx = sh->pd_idx, i;
+ struct async_submit_ctl submit;
+
+ /* existing parity data subtracted */
+ struct page *xor_dest = xor_srcs[count++] = sh->dev[pd_idx].page;
+
+ BUG_ON(sh->batch_head);
+ 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;
+ }
+
+ init_async_submit(&submit, ASYNC_TX_FENCE|ASYNC_TX_XOR_DROP_DST, tx,
+ ops_complete_prexor, sh, to_addr_conv(sh, percpu, 0));
+ tx = async_xor(xor_dest, xor_srcs, 0, count, STRIPE_SIZE, &submit);
+
+ return tx;
+}
+
+static struct dma_async_tx_descriptor *
+ops_run_prexor6(struct stripe_head *sh, struct raid5_percpu *percpu,
+ struct dma_async_tx_descriptor *tx)
+{
+ struct page **blocks = to_addr_page(percpu, 0);
+ int count;
+ struct async_submit_ctl submit;
+
+ pr_debug("%s: stripe %llu\n", __func__,
+ (unsigned long long)sh->sector);
+
+ count = set_syndrome_sources(blocks, sh, SYNDROME_SRC_WANT_DRAIN);
+
+ init_async_submit(&submit, ASYNC_TX_FENCE|ASYNC_TX_PQ_XOR_DST, tx,
+ ops_complete_prexor, sh, to_addr_conv(sh, percpu, 0));
+ tx = async_gen_syndrome(blocks, 0, count+2, STRIPE_SIZE, &submit);
+
+ 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;
+ struct stripe_head *head_sh = sh;
+
+ pr_debug("%s: stripe %llu\n", __func__,
+ (unsigned long long)sh->sector);
+
+ for (i = disks; i--; ) {
+ struct r5dev *dev;
+ struct bio *chosen;
+
+ sh = head_sh;
+ if (test_and_clear_bit(R5_Wantdrain, &head_sh->dev[i].flags)) {
+ struct bio *wbi;
+
+again:
+ dev = &sh->dev[i];
+ spin_lock_irq(&sh->stripe_lock);
+ chosen = dev->towrite;
+ dev->towrite = NULL;
+ sh->overwrite_disks = 0;
+ BUG_ON(dev->written);
+ wbi = dev->written = chosen;
+ spin_unlock_irq(&sh->stripe_lock);
+ WARN_ON(dev->page != dev->orig_page);
+
+ while (wbi && wbi->bi_iter.bi_sector <
+ dev->sector + STRIPE_SECTORS) {
+ if (wbi->bi_rw & REQ_FUA)
+ set_bit(R5_WantFUA, &dev->flags);
+ if (wbi->bi_rw & REQ_SYNC)
+ set_bit(R5_SyncIO, &dev->flags);
+ if (wbi->bi_rw & REQ_DISCARD)
+ set_bit(R5_Discard, &dev->flags);
+ else {
+ tx = async_copy_data(1, wbi, &dev->page,
+ dev->sector, tx, sh);
+ if (dev->page != dev->orig_page) {
+ set_bit(R5_SkipCopy, &dev->flags);
+ clear_bit(R5_UPTODATE, &dev->flags);
+ clear_bit(R5_OVERWRITE, &dev->flags);
+ }
+ }
+ wbi = r5_next_bio(wbi, dev->sector);
+ }
+
+ if (head_sh->batch_head) {
+ sh = list_first_entry(&sh->batch_list,
+ struct stripe_head,
+ batch_list);
+ if (sh == head_sh)
+ continue;
+ goto again;
+ }
+ }
+ }
+
+ return tx;
+}
+
+static void ops_complete_reconstruct(void *stripe_head_ref)
+{
+ struct stripe_head *sh = stripe_head_ref;
+ int disks = sh->disks;
+ int pd_idx = sh->pd_idx;
+ int qd_idx = sh->qd_idx;
+ int i;
+ bool fua = false, sync = false, discard = false;
+
+ pr_debug("%s: stripe %llu\n", __func__,
+ (unsigned long long)sh->sector);
+
+ for (i = disks; i--; ) {
+ fua |= test_bit(R5_WantFUA, &sh->dev[i].flags);
+ sync |= test_bit(R5_SyncIO, &sh->dev[i].flags);
+ discard |= test_bit(R5_Discard, &sh->dev[i].flags);
+ }
+
+ for (i = disks; i--; ) {
+ struct r5dev *dev = &sh->dev[i];
+
+ if (dev->written || i == pd_idx || i == qd_idx) {
+ if (!discard && !test_bit(R5_SkipCopy, &dev->flags))
+ set_bit(R5_UPTODATE, &dev->flags);
+ if (fua)
+ set_bit(R5_WantFUA, &dev->flags);
+ if (sync)
+ set_bit(R5_SyncIO, &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_reconstruct5(struct stripe_head *sh, struct raid5_percpu *percpu,
+ struct dma_async_tx_descriptor *tx)
+{
+ int disks = sh->disks;
+ struct page **xor_srcs;
+ struct async_submit_ctl submit;
+ int count, pd_idx = sh->pd_idx, i;
+ struct page *xor_dest;
+ int prexor = 0;
+ unsigned long flags;
+ int j = 0;
+ struct stripe_head *head_sh = sh;
+ int last_stripe;
+
+ pr_debug("%s: stripe %llu\n", __func__,
+ (unsigned long long)sh->sector);
+
+ for (i = 0; i < sh->disks; i++) {
+ if (pd_idx == i)
+ continue;
+ if (!test_bit(R5_Discard, &sh->dev[i].flags))
+ break;
+ }
+ if (i >= sh->disks) {
+ atomic_inc(&sh->count);
+ set_bit(R5_Discard, &sh->dev[pd_idx].flags);
+ ops_complete_reconstruct(sh);
+ return;
+ }
+again:
+ count = 0;
+ xor_srcs = to_addr_page(percpu, j);
+ /* check if prexor is active which means only process blocks
+ * that are part of a read-modify-write (written)
+ */
+ if (head_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 (head_sh->dev[i].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
+ */
+ last_stripe = !head_sh->batch_head ||
+ list_first_entry(&sh->batch_list,
+ struct stripe_head, batch_list) == head_sh;
+ if (last_stripe) {
+ flags = ASYNC_TX_ACK |
+ (prexor ? ASYNC_TX_XOR_DROP_DST : ASYNC_TX_XOR_ZERO_DST);
+
+ atomic_inc(&head_sh->count);
+ init_async_submit(&submit, flags, tx, ops_complete_reconstruct, head_sh,
+ to_addr_conv(sh, percpu, j));
+ } else {
+ flags = prexor ? ASYNC_TX_XOR_DROP_DST : ASYNC_TX_XOR_ZERO_DST;
+ init_async_submit(&submit, flags, tx, NULL, NULL,
+ to_addr_conv(sh, percpu, j));
+ }
+
+ if (unlikely(count == 1))
+ tx = async_memcpy(xor_dest, xor_srcs[0], 0, 0, STRIPE_SIZE, &submit);
+ else
+ tx = async_xor(xor_dest, xor_srcs, 0, count, STRIPE_SIZE, &submit);
+ if (!last_stripe) {
+ j++;
+ sh = list_first_entry(&sh->batch_list, struct stripe_head,
+ batch_list);
+ goto again;
+ }
+}
+
+static void
+ops_run_reconstruct6(struct stripe_head *sh, struct raid5_percpu *percpu,
+ struct dma_async_tx_descriptor *tx)
+{
+ struct async_submit_ctl submit;
+ struct page **blocks;
+ int count, i, j = 0;
+ struct stripe_head *head_sh = sh;
+ int last_stripe;
+ int synflags;
+ unsigned long txflags;
+
+ pr_debug("%s: stripe %llu\n", __func__, (unsigned long long)sh->sector);
+
+ for (i = 0; i < sh->disks; i++) {
+ if (sh->pd_idx == i || sh->qd_idx == i)
+ continue;
+ if (!test_bit(R5_Discard, &sh->dev[i].flags))
+ break;
+ }
+ if (i >= sh->disks) {
+ atomic_inc(&sh->count);
+ set_bit(R5_Discard, &sh->dev[sh->pd_idx].flags);
+ set_bit(R5_Discard, &sh->dev[sh->qd_idx].flags);
+ ops_complete_reconstruct(sh);
+ return;
+ }
+
+again:
+ blocks = to_addr_page(percpu, j);
+
+ if (sh->reconstruct_state == reconstruct_state_prexor_drain_run) {
+ synflags = SYNDROME_SRC_WRITTEN;
+ txflags = ASYNC_TX_ACK | ASYNC_TX_PQ_XOR_DST;
+ } else {
+ synflags = SYNDROME_SRC_ALL;
+ txflags = ASYNC_TX_ACK;
+ }
+
+ count = set_syndrome_sources(blocks, sh, synflags);
+ last_stripe = !head_sh->batch_head ||
+ list_first_entry(&sh->batch_list,
+ struct stripe_head, batch_list) == head_sh;
+
+ if (last_stripe) {
+ atomic_inc(&head_sh->count);
+ init_async_submit(&submit, txflags, tx, ops_complete_reconstruct,
+ head_sh, to_addr_conv(sh, percpu, j));
+ } else
+ init_async_submit(&submit, 0, tx, NULL, NULL,
+ to_addr_conv(sh, percpu, j));
+ tx = async_gen_syndrome(blocks, 0, count+2, STRIPE_SIZE, &submit);
+ if (!last_stripe) {
+ j++;
+ sh = list_first_entry(&sh->batch_list, struct stripe_head,
+ batch_list);
+ goto again;
+ }
+}
+
+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_p(struct stripe_head *sh, struct raid5_percpu *percpu)
+{
+ int disks = sh->disks;
+ int pd_idx = sh->pd_idx;
+ int qd_idx = sh->qd_idx;
+ struct page *xor_dest;
+ struct page **xor_srcs = to_addr_page(percpu, 0);
+ struct dma_async_tx_descriptor *tx;
+ struct async_submit_ctl submit;
+ int count;
+ int i;
+
+ pr_debug("%s: stripe %llu\n", __func__,
+ (unsigned long long)sh->sector);
+
+ BUG_ON(sh->batch_head);
+ count = 0;
+ xor_dest = sh->dev[pd_idx].page;
+ xor_srcs[count++] = xor_dest;
+ for (i = disks; i--; ) {
+ if (i == pd_idx || i == qd_idx)
+ continue;
+ xor_srcs[count++] = sh->dev[i].page;
+ }
+
+ init_async_submit(&submit, 0, NULL, NULL, NULL,
+ to_addr_conv(sh, percpu, 0));
+ tx = async_xor_val(xor_dest, xor_srcs, 0, count, STRIPE_SIZE,
+ &sh->ops.zero_sum_result, &submit);
+
+ atomic_inc(&sh->count);
+ init_async_submit(&submit, ASYNC_TX_ACK, tx, ops_complete_check, sh, NULL);
+ tx = async_trigger_callback(&submit);
+}
+
+static void ops_run_check_pq(struct stripe_head *sh, struct raid5_percpu *percpu, int checkp)
+{
+ struct page **srcs = to_addr_page(percpu, 0);
+ struct async_submit_ctl submit;
+ int count;
+
+ pr_debug("%s: stripe %llu checkp: %d\n", __func__,
+ (unsigned long long)sh->sector, checkp);
+
+ BUG_ON(sh->batch_head);
+ count = set_syndrome_sources(srcs, sh, SYNDROME_SRC_ALL);
+ if (!checkp)
+ srcs[count] = NULL;
+
+ atomic_inc(&sh->count);
+ init_async_submit(&submit, ASYNC_TX_ACK, NULL, ops_complete_check,
+ sh, to_addr_conv(sh, percpu, 0));
+ async_syndrome_val(srcs, 0, count+2, STRIPE_SIZE,
+ &sh->ops.zero_sum_result, percpu->spare_page, &submit);
+}
+
+static void raid_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;
+ struct r5conf *conf = sh->raid_conf;
+ int level = conf->level;
+ struct raid5_percpu *percpu;
+ unsigned long cpu;
+
+ cpu = get_cpu_light();
+ percpu = per_cpu_ptr(conf->percpu, cpu);
+ spin_lock(&percpu->lock);
+ if (test_bit(STRIPE_OP_BIOFILL, &ops_request)) {
+ ops_run_biofill(sh);
+ overlap_clear++;
+ }
+
+ if (test_bit(STRIPE_OP_COMPUTE_BLK, &ops_request)) {
+ if (level < 6)
+ tx = ops_run_compute5(sh, percpu);
+ else {
+ if (sh->ops.target2 < 0 || sh->ops.target < 0)
+ tx = ops_run_compute6_1(sh, percpu);
+ else
+ tx = ops_run_compute6_2(sh, percpu);
+ }
+ /* terminate the chain if reconstruct is not set to be run */
+ if (tx && !test_bit(STRIPE_OP_RECONSTRUCT, &ops_request))
+ async_tx_ack(tx);
+ }
+
+ if (test_bit(STRIPE_OP_PREXOR, &ops_request)) {
+ if (level < 6)
+ tx = ops_run_prexor5(sh, percpu, tx);
+ else
+ tx = ops_run_prexor6(sh, percpu, tx);
+ }
+
+ if (test_bit(STRIPE_OP_BIODRAIN, &ops_request)) {
+ tx = ops_run_biodrain(sh, tx);
+ overlap_clear++;
+ }
+
+ if (test_bit(STRIPE_OP_RECONSTRUCT, &ops_request)) {
+ if (level < 6)
+ ops_run_reconstruct5(sh, percpu, tx);
+ else
+ ops_run_reconstruct6(sh, percpu, tx);
+ }
+
+ if (test_bit(STRIPE_OP_CHECK, &ops_request)) {
+ if (sh->check_state == check_state_run)
+ ops_run_check_p(sh, percpu);
+ else if (sh->check_state == check_state_run_q)
+ ops_run_check_pq(sh, percpu, 0);
+ else if (sh->check_state == check_state_run_pq)
+ ops_run_check_pq(sh, percpu, 1);
+ else
+ BUG();
+ }
+
+ if (overlap_clear && !sh->batch_head)
+ 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);
+ }
+ spin_unlock(&percpu->lock);
+ put_cpu_light();
+}
+
+static struct stripe_head *alloc_stripe(struct kmem_cache *sc, gfp_t gfp)
+{
+ struct stripe_head *sh;
+
+ sh = kmem_cache_zalloc(sc, gfp);
+ if (sh) {
+ spin_lock_init(&sh->stripe_lock);
+ spin_lock_init(&sh->batch_lock);
+ INIT_LIST_HEAD(&sh->batch_list);
+ INIT_LIST_HEAD(&sh->lru);
+ atomic_set(&sh->count, 1);
+ }
+ return sh;
+}
+static int grow_one_stripe(struct r5conf *conf, gfp_t gfp)
+{
+ struct stripe_head *sh;
+
+ sh = alloc_stripe(conf->slab_cache, gfp);
+ if (!sh)
+ return 0;
+
+ sh->raid_conf = conf;
+
+ if (grow_buffers(sh, gfp)) {
+ shrink_buffers(sh);
+ kmem_cache_free(conf->slab_cache, sh);
+ return 0;
+ }
+ sh->hash_lock_index =
+ conf->max_nr_stripes % NR_STRIPE_HASH_LOCKS;
+ /* we just created an active stripe so... */
+ atomic_inc(&conf->active_stripes);
+
+ release_stripe(sh);
+ conf->max_nr_stripes++;
+ return 1;
+}
+
+static int grow_stripes(struct r5conf *conf, int num)
+{
+ struct kmem_cache *sc;
+ int devs = max(conf->raid_disks, conf->previous_raid_disks);
+
+ if (conf->mddev->gendisk)
+ sprintf(conf->cache_name[0],
+ "raid%d-%s", conf->level, mdname(conf->mddev));
+ else
+ sprintf(conf->cache_name[0],
+ "raid%d-%p", conf->level, conf->mddev);
+ sprintf(conf->cache_name[1], "%s-alt", conf->cache_name[0]);
+
+ 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, GFP_KERNEL))
+ return 1;
+
+ return 0;
+}
+
+/**
+ * scribble_len - return the required size of the scribble region
+ * @num - total number of disks in the array
+ *
+ * The size must be enough to contain:
+ * 1/ a struct page pointer for each device in the array +2
+ * 2/ room to convert each entry in (1) to its corresponding dma
+ * (dma_map_page()) or page (page_address()) address.
+ *
+ * Note: the +2 is for the destination buffers of the ddf/raid6 case where we
+ * calculate over all devices (not just the data blocks), using zeros in place
+ * of the P and Q blocks.
+ */
+static struct flex_array *scribble_alloc(int num, int cnt, gfp_t flags)
+{
+ struct flex_array *ret;
+ size_t len;
+
+ len = sizeof(struct page *) * (num+2) + sizeof(addr_conv_t) * (num+2);
+ ret = flex_array_alloc(len, cnt, flags);
+ if (!ret)
+ return NULL;
+ /* always prealloc all elements, so no locking is required */
+ if (flex_array_prealloc(ret, 0, cnt, flags)) {
+ flex_array_free(ret);
+ return NULL;
+ }
+ return ret;
+}
+
+static int resize_chunks(struct r5conf *conf, int new_disks, int new_sectors)
+{
+ unsigned long cpu;
+ int err = 0;
+
+ mddev_suspend(conf->mddev);
+ get_online_cpus();
+ for_each_present_cpu(cpu) {
+ struct raid5_percpu *percpu;
+ struct flex_array *scribble;
+
+ percpu = per_cpu_ptr(conf->percpu, cpu);
+ scribble = scribble_alloc(new_disks,
+ new_sectors / STRIPE_SECTORS,
+ GFP_NOIO);
+
+ if (scribble) {
+ flex_array_free(percpu->scribble);
+ percpu->scribble = scribble;
+ } else {
+ err = -ENOMEM;
+ break;
+ }
+ }
+ put_online_cpus();
+ mddev_resume(conf->mddev);
+ return err;
+}
+
+static int resize_stripes(struct r5conf *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 transfer 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;
+ int hash, cnt;
+
+ 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 = alloc_stripe(sc, GFP_KERNEL);
+ if (!nsh)
+ break;
+
+ nsh->raid_conf = conf;
+ 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
+ */
+ hash = 0;
+ cnt = 0;
+ list_for_each_entry(nsh, &newstripes, lru) {
+ lock_device_hash_lock(conf, hash);
+ wait_event_cmd(conf->wait_for_stripe,
+ !list_empty(conf->inactive_list + hash),
+ unlock_device_hash_lock(conf, hash),
+ lock_device_hash_lock(conf, hash));
+ osh = get_free_stripe(conf, hash);
+ unlock_device_hash_lock(conf, hash);
+
+ for(i=0; i<conf->pool_size; i++) {
+ nsh->dev[i].page = osh->dev[i].page;
+ nsh->dev[i].orig_page = osh->dev[i].page;
+ }
+ nsh->hash_lock_index = hash;
+ kmem_cache_free(conf->slab_cache, osh);
+ cnt++;
+ if (cnt >= conf->max_nr_stripes / NR_STRIPE_HASH_LOCKS +
+ !!((conf->max_nr_stripes % NR_STRIPE_HASH_LOCKS) > hash)) {
+ hash++;
+ cnt = 0;
+ }
+ }
+ 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 and the scribble region
+ */
+ 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;
+ nsh->dev[i].orig_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;
+ if (!err)
+ conf->pool_size = newsize;
+ return err;
+}
+
+static int drop_one_stripe(struct r5conf *conf)
+{
+ struct stripe_head *sh;
+ int hash = (conf->max_nr_stripes - 1) % NR_STRIPE_HASH_LOCKS;
+
+ spin_lock_irq(conf->hash_locks + hash);
+ sh = get_free_stripe(conf, hash);
+ spin_unlock_irq(conf->hash_locks + hash);
+ if (!sh)
+ return 0;
+ BUG_ON(atomic_read(&sh->count));
+ shrink_buffers(sh);
+ kmem_cache_free(conf->slab_cache, sh);
+ atomic_dec(&conf->active_stripes);
+ conf->max_nr_stripes--;
+ return 1;
+}
+
+static void shrink_stripes(struct r5conf *conf)
+{
+ while (conf->max_nr_stripes &&
+ 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;
+ struct r5conf *conf = sh->raid_conf;
+ int disks = sh->disks, i;
+ int uptodate = test_bit(BIO_UPTODATE, &bi->bi_flags);
+ char b[BDEVNAME_SIZE];
+ struct md_rdev *rdev = NULL;
+ sector_t s;
+
+ 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 (test_bit(R5_ReadRepl, &sh->dev[i].flags))
+ /* If replacement finished while this request was outstanding,
+ * 'replacement' might be NULL already.
+ * In that case it moved down to 'rdev'.
+ * rdev is not removed until all requests are finished.
+ */
+ rdev = conf->disks[i].replacement;
+ if (!rdev)
+ rdev = conf->disks[i].rdev;
+
+ if (use_new_offset(conf, sh))
+ s = sh->sector + rdev->new_data_offset;
+ else
+ s = sh->sector + rdev->data_offset;
+ if (uptodate) {
+ set_bit(R5_UPTODATE, &sh->dev[i].flags);
+ if (test_bit(R5_ReadError, &sh->dev[i].flags)) {
+ /* Note that this cannot happen on a
+ * replacement device. We just fail those on
+ * any error
+ */
+ printk_ratelimited(
+ KERN_INFO
+ "md/raid:%s: read error corrected"
+ " (%lu sectors at %llu on %s)\n",
+ mdname(conf->mddev), STRIPE_SECTORS,
+ (unsigned long long)s,
+ bdevname(rdev->bdev, b));
+ atomic_add(STRIPE_SECTORS, &rdev->corrected_errors);
+ clear_bit(R5_ReadError, &sh->dev[i].flags);
+ clear_bit(R5_ReWrite, &sh->dev[i].flags);
+ } else if (test_bit(R5_ReadNoMerge, &sh->dev[i].flags))
+ clear_bit(R5_ReadNoMerge, &sh->dev[i].flags);
+
+ if (atomic_read(&rdev->read_errors))
+ atomic_set(&rdev->read_errors, 0);
+ } else {
+ const char *bdn = bdevname(rdev->bdev, b);
+ int retry = 0;
+ int set_bad = 0;
+
+ clear_bit(R5_UPTODATE, &sh->dev[i].flags);
+ atomic_inc(&rdev->read_errors);
+ if (test_bit(R5_ReadRepl, &sh->dev[i].flags))
+ printk_ratelimited(
+ KERN_WARNING
+ "md/raid:%s: read error on replacement device "
+ "(sector %llu on %s).\n",
+ mdname(conf->mddev),
+ (unsigned long long)s,
+ bdn);
+ else if (conf->mddev->degraded >= conf->max_degraded) {
+ set_bad = 1;
+ printk_ratelimited(
+ KERN_WARNING
+ "md/raid:%s: read error not correctable "
+ "(sector %llu on %s).\n",
+ mdname(conf->mddev),
+ (unsigned long long)s,
+ bdn);
+ } else if (test_bit(R5_ReWrite, &sh->dev[i].flags)) {
+ /* Oh, no!!! */
+ set_bad = 1;
+ printk_ratelimited(
+ KERN_WARNING
+ "md/raid:%s: read error NOT corrected!! "
+ "(sector %llu on %s).\n",
+ mdname(conf->mddev),
+ (unsigned long long)s,
+ bdn);
+ } else if (atomic_read(&rdev->read_errors)
+ > conf->max_nr_stripes)
+ printk(KERN_WARNING
+ "md/raid:%s: Too many read errors, failing device %s.\n",
+ mdname(conf->mddev), bdn);
+ else
+ retry = 1;
+ if (set_bad && test_bit(In_sync, &rdev->flags)
+ && !test_bit(R5_ReadNoMerge, &sh->dev[i].flags))
+ retry = 1;
+ if (retry)
+ if (test_bit(R5_ReadNoMerge, &sh->dev[i].flags)) {
+ set_bit(R5_ReadError, &sh->dev[i].flags);
+ clear_bit(R5_ReadNoMerge, &sh->dev[i].flags);
+ } else
+ set_bit(R5_ReadNoMerge, &sh->dev[i].flags);
+ else {
+ clear_bit(R5_ReadError, &sh->dev[i].flags);
+ clear_bit(R5_ReWrite, &sh->dev[i].flags);
+ if (!(set_bad
+ && test_bit(In_sync, &rdev->flags)
+ && rdev_set_badblocks(
+ rdev, sh->sector, STRIPE_SECTORS, 0)))
+ md_error(conf->mddev, rdev);
+ }
+ }
+ rdev_dec_pending(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;
+ struct r5conf *conf = sh->raid_conf;
+ int disks = sh->disks, i;
+ struct md_rdev *uninitialized_var(rdev);
+ int uptodate = test_bit(BIO_UPTODATE, &bi->bi_flags);
+ sector_t first_bad;
+ int bad_sectors;
+ int replacement = 0;
+
+ for (i = 0 ; i < disks; i++) {
+ if (bi == &sh->dev[i].req) {
+ rdev = conf->disks[i].rdev;
+ break;
+ }
+ if (bi == &sh->dev[i].rreq) {
+ rdev = conf->disks[i].replacement;
+ if (rdev)
+ replacement = 1;
+ else
+ /* rdev was removed and 'replacement'
+ * replaced it. rdev is not removed
+ * until all requests are finished.
+ */
+ rdev = conf->disks[i].rdev;
+ 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 (replacement) {
+ if (!uptodate)
+ md_error(conf->mddev, rdev);
+ else if (is_badblock(rdev, sh->sector,
+ STRIPE_SECTORS,
+ &first_bad, &bad_sectors))
+ set_bit(R5_MadeGoodRepl, &sh->dev[i].flags);
+ } else {
+ if (!uptodate) {
+ set_bit(STRIPE_DEGRADED, &sh->state);
+ set_bit(WriteErrorSeen, &rdev->flags);
+ set_bit(R5_WriteError, &sh->dev[i].flags);
+ if (!test_and_set_bit(WantReplacement, &rdev->flags))
+ set_bit(MD_RECOVERY_NEEDED,
+ &rdev->mddev->recovery);
+ } else if (is_badblock(rdev, sh->sector,
+ STRIPE_SECTORS,
+ &first_bad, &bad_sectors)) {
+ set_bit(R5_MadeGood, &sh->dev[i].flags);
+ if (test_bit(R5_ReadError, &sh->dev[i].flags))
+ /* That was a successful write so make
+ * sure it looks like we already did
+ * a re-write.
+ */
+ set_bit(R5_ReWrite, &sh->dev[i].flags);
+ }
+ }
+ rdev_dec_pending(rdev, conf->mddev);
+
+ if (sh->batch_head && !uptodate && !replacement)
+ set_bit(STRIPE_BATCH_ERR, &sh->batch_head->state);
+
+ if (!test_and_clear_bit(R5_DOUBLE_LOCKED, &sh->dev[i].flags))
+ clear_bit(R5_LOCKED, &sh->dev[i].flags);
+ set_bit(STRIPE_HANDLE, &sh->state);
+ release_stripe(sh);
+
+ if (sh->batch_head && sh != sh->batch_head)
+ release_stripe(sh->batch_head);
+}
+
+static sector_t compute_blocknr(struct stripe_head *sh, int i, int previous);
+
+static void raid5_build_block(struct stripe_head *sh, int i, int previous)
+{
+ struct r5dev *dev = &sh->dev[i];
+
+ bio_init(&dev->req);
+ dev->req.bi_io_vec = &dev->vec;
+ dev->req.bi_max_vecs = 1;
+ dev->req.bi_private = sh;
+
+ bio_init(&dev->rreq);
+ dev->rreq.bi_io_vec = &dev->rvec;
+ dev->rreq.bi_max_vecs = 1;
+ dev->rreq.bi_private = sh;
+
+ dev->flags = 0;
+ dev->sector = compute_blocknr(sh, i, previous);
+}
+
+static void error(struct mddev *mddev, struct md_rdev *rdev)
+{
+ char b[BDEVNAME_SIZE];
+ struct r5conf *conf = mddev->private;
+ unsigned long flags;
+ pr_debug("raid456: error called\n");
+
+ spin_lock_irqsave(&conf->device_lock, flags);
+ clear_bit(In_sync, &rdev->flags);
+ mddev->degraded = calc_degraded(conf);
+ spin_unlock_irqrestore(&conf->device_lock, flags);
+ set_bit(MD_RECOVERY_INTR, &mddev->recovery);
+
+ set_bit(Blocked, &rdev->flags);
+ set_bit(Faulty, &rdev->flags);
+ set_bit(MD_CHANGE_DEVS, &mddev->flags);
+ printk(KERN_ALERT
+ "md/raid:%s: Disk failure on %s, disabling device.\n"
+ "md/raid:%s: Operation continuing on %d devices.\n",
+ mdname(mddev),
+ bdevname(rdev->bdev, b),
+ mdname(mddev),
+ 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(struct r5conf *conf, sector_t r_sector,
+ int previous, int *dd_idx,
+ struct stripe_head *sh)
+{
+ sector_t stripe, stripe2;
+ sector_t chunk_number;
+ unsigned int chunk_offset;
+ int pd_idx, qd_idx;
+ int ddf_layout = 0;
+ sector_t new_sector;
+ int algorithm = previous ? conf->prev_algo
+ : conf->algorithm;
+ int sectors_per_chunk = previous ? conf->prev_chunk_sectors
+ : conf->chunk_sectors;
+ int raid_disks = previous ? conf->previous_raid_disks
+ : conf->raid_disks;
+ int data_disks = raid_disks - conf->max_degraded;
+
+ /* First compute the information on this sector */
+
+ /*
+ * Compute the chunk number and the sector offset inside the chunk
+ */
+ chunk_offset = sector_div(r_sector, sectors_per_chunk);
+ chunk_number = r_sector;
+
+ /*
+ * Compute the stripe number
+ */
+ stripe = chunk_number;
+ *dd_idx = sector_div(stripe, data_disks);
+ stripe2 = stripe;
+ /*
+ * Select the parity disk based on the user selected algorithm.
+ */
+ pd_idx = qd_idx = -1;
+ switch(conf->level) {
+ case 4:
+ pd_idx = data_disks;
+ break;
+ case 5:
+ switch (algorithm) {
+ case ALGORITHM_LEFT_ASYMMETRIC:
+ pd_idx = data_disks - sector_div(stripe2, raid_disks);
+ if (*dd_idx >= pd_idx)
+ (*dd_idx)++;
+ break;
+ case ALGORITHM_RIGHT_ASYMMETRIC:
+ pd_idx = sector_div(stripe2, raid_disks);
+ if (*dd_idx >= pd_idx)
+ (*dd_idx)++;
+ break;
+ case ALGORITHM_LEFT_SYMMETRIC:
+ pd_idx = data_disks - sector_div(stripe2, raid_disks);
+ *dd_idx = (pd_idx + 1 + *dd_idx) % raid_disks;
+ break;
+ case ALGORITHM_RIGHT_SYMMETRIC:
+ pd_idx = sector_div(stripe2, raid_disks);
+ *dd_idx = (pd_idx + 1 + *dd_idx) % raid_disks;
+ break;
+ case ALGORITHM_PARITY_0:
+ pd_idx = 0;
+ (*dd_idx)++;
+ break;
+ case ALGORITHM_PARITY_N:
+ pd_idx = data_disks;
+ break;
+ default:
+ BUG();
+ }
+ break;
+ case 6:
+
+ switch (algorithm) {
+ case ALGORITHM_LEFT_ASYMMETRIC:
+ pd_idx = raid_disks - 1 - sector_div(stripe2, raid_disks);
+ qd_idx = pd_idx + 1;
+ if (pd_idx == raid_disks-1) {
+ (*dd_idx)++; /* Q D D D P */
+ qd_idx = 0;
+ } else if (*dd_idx >= pd_idx)
+ (*dd_idx) += 2; /* D D P Q D */
+ break;
+ case ALGORITHM_RIGHT_ASYMMETRIC:
+ pd_idx = sector_div(stripe2, raid_disks);
+ qd_idx = pd_idx + 1;
+ if (pd_idx == raid_disks-1) {
+ (*dd_idx)++; /* Q D D D P */
+ qd_idx = 0;
+ } else if (*dd_idx >= pd_idx)
+ (*dd_idx) += 2; /* D D P Q D */
+ break;
+ case ALGORITHM_LEFT_SYMMETRIC:
+ pd_idx = raid_disks - 1 - sector_div(stripe2, raid_disks);
+ qd_idx = (pd_idx + 1) % raid_disks;
+ *dd_idx = (pd_idx + 2 + *dd_idx) % raid_disks;
+ break;
+ case ALGORITHM_RIGHT_SYMMETRIC:
+ pd_idx = sector_div(stripe2, raid_disks);
+ qd_idx = (pd_idx + 1) % raid_disks;
+ *dd_idx = (pd_idx + 2 + *dd_idx) % raid_disks;
+ break;
+
+ case ALGORITHM_PARITY_0:
+ pd_idx = 0;
+ qd_idx = 1;
+ (*dd_idx) += 2;
+ break;
+ case ALGORITHM_PARITY_N:
+ pd_idx = data_disks;
+ qd_idx = data_disks + 1;
+ break;
+
+ case ALGORITHM_ROTATING_ZERO_RESTART:
+ /* Exactly the same as RIGHT_ASYMMETRIC, but or
+ * of blocks for computing Q is different.
+ */
+ pd_idx = sector_div(stripe2, raid_disks);
+ qd_idx = pd_idx + 1;
+ if (pd_idx == raid_disks-1) {
+ (*dd_idx)++; /* Q D D D P */
+ qd_idx = 0;
+ } else if (*dd_idx >= pd_idx)
+ (*dd_idx) += 2; /* D D P Q D */
+ ddf_layout = 1;
+ break;
+
+ case ALGORITHM_ROTATING_N_RESTART:
+ /* Same a left_asymmetric, by first stripe is
+ * D D D P Q rather than
+ * Q D D D P
+ */
+ stripe2 += 1;
+ pd_idx = raid_disks - 1 - sector_div(stripe2, raid_disks);
+ qd_idx = pd_idx + 1;
+ if (pd_idx == raid_disks-1) {
+ (*dd_idx)++; /* Q D D D P */
+ qd_idx = 0;
+ } else if (*dd_idx >= pd_idx)
+ (*dd_idx) += 2; /* D D P Q D */
+ ddf_layout = 1;
+ break;
+
+ case ALGORITHM_ROTATING_N_CONTINUE:
+ /* Same as left_symmetric but Q is before P */
+ pd_idx = raid_disks - 1 - sector_div(stripe2, raid_disks);
+ qd_idx = (pd_idx + raid_disks - 1) % raid_disks;
+ *dd_idx = (pd_idx + 1 + *dd_idx) % raid_disks;
+ ddf_layout = 1;
+ break;
+
+ case ALGORITHM_LEFT_ASYMMETRIC_6:
+ /* RAID5 left_asymmetric, with Q on last device */
+ pd_idx = data_disks - sector_div(stripe2, raid_disks-1);
+ if (*dd_idx >= pd_idx)
+ (*dd_idx)++;
+ qd_idx = raid_disks - 1;
+ break;
+
+ case ALGORITHM_RIGHT_ASYMMETRIC_6:
+ pd_idx = sector_div(stripe2, raid_disks-1);
+ if (*dd_idx >= pd_idx)
+ (*dd_idx)++;
+ qd_idx = raid_disks - 1;
+ break;
+
+ case ALGORITHM_LEFT_SYMMETRIC_6:
+ pd_idx = data_disks - sector_div(stripe2, raid_disks-1);
+ *dd_idx = (pd_idx + 1 + *dd_idx) % (raid_disks-1);
+ qd_idx = raid_disks - 1;
+ break;
+
+ case ALGORITHM_RIGHT_SYMMETRIC_6:
+ pd_idx = sector_div(stripe2, raid_disks-1);
+ *dd_idx = (pd_idx + 1 + *dd_idx) % (raid_disks-1);
+ qd_idx = raid_disks - 1;
+ break;
+
+ case ALGORITHM_PARITY_0_6:
+ pd_idx = 0;
+ (*dd_idx)++;
+ qd_idx = raid_disks - 1;
+ break;
+
+ default:
+ BUG();
+ }
+ break;
+ }
+
+ if (sh) {
+ sh->pd_idx = pd_idx;
+ sh->qd_idx = qd_idx;
+ sh->ddf_layout = ddf_layout;
+ }
+ /*
+ * Finally, compute the new sector number
+ */
+ new_sector = (sector_t)stripe * sectors_per_chunk + chunk_offset;
+ return new_sector;
+}
+
+static sector_t compute_blocknr(struct stripe_head *sh, int i, int previous)
+{
+ struct r5conf *conf = sh->raid_conf;
+ int raid_disks = sh->disks;
+ int data_disks = raid_disks - conf->max_degraded;
+ sector_t new_sector = sh->sector, check;
+ int sectors_per_chunk = previous ? conf->prev_chunk_sectors
+ : conf->chunk_sectors;
+ int algorithm = previous ? conf->prev_algo
+ : conf->algorithm;
+ sector_t stripe;
+ int chunk_offset;
+ sector_t chunk_number;
+ int dummy1, dd_idx = i;
+ sector_t r_sector;
+ struct stripe_head sh2;
+
+ chunk_offset = sector_div(new_sector, sectors_per_chunk);
+ stripe = new_sector;
+
+ if (i == sh->pd_idx)
+ return 0;
+ switch(conf->level) {
+ case 4: break;
+ case 5:
+ switch (algorithm) {
+ case ALGORITHM_LEFT_ASYMMETRIC:
+ case ALGORITHM_RIGHT_ASYMMETRIC:
+ if (i > sh->pd_idx)
+ i--;
+ break;
+ case ALGORITHM_LEFT_SYMMETRIC:
+ case ALGORITHM_RIGHT_SYMMETRIC:
+ if (i < sh->pd_idx)
+ i += raid_disks;
+ i -= (sh->pd_idx + 1);
+ break;
+ case ALGORITHM_PARITY_0:
+ i -= 1;
+ break;
+ case ALGORITHM_PARITY_N:
+ break;
+ default:
+ BUG();
+ }
+ break;
+ case 6:
+ if (i == sh->qd_idx)
+ return 0; /* It is the Q disk */
+ switch (algorithm) {
+ case ALGORITHM_LEFT_ASYMMETRIC:
+ case ALGORITHM_RIGHT_ASYMMETRIC:
+ case ALGORITHM_ROTATING_ZERO_RESTART:
+ case ALGORITHM_ROTATING_N_RESTART:
+ if (sh->pd_idx == raid_disks-1)
+ i--; /* Q D D D P */
+ else if (i > sh->pd_idx)
+ i -= 2; /* D D P Q D */
+ break;
+ case ALGORITHM_LEFT_SYMMETRIC:
+ case ALGORITHM_RIGHT_SYMMETRIC:
+ if (sh->pd_idx == raid_disks-1)
+ i--; /* Q D D D P */
+ else {
+ /* D D P Q D */
+ if (i < sh->pd_idx)
+ i += raid_disks;
+ i -= (sh->pd_idx + 2);
+ }
+ break;
+ case ALGORITHM_PARITY_0:
+ i -= 2;
+ break;
+ case ALGORITHM_PARITY_N:
+ break;
+ case ALGORITHM_ROTATING_N_CONTINUE:
+ /* Like left_symmetric, but P is before Q */
+ if (sh->pd_idx == 0)
+ i--; /* P D D D Q */
+ else {
+ /* D D Q P D */
+ if (i < sh->pd_idx)
+ i += raid_disks;
+ i -= (sh->pd_idx + 1);
+ }
+ break;
+ case ALGORITHM_LEFT_ASYMMETRIC_6:
+ case ALGORITHM_RIGHT_ASYMMETRIC_6:
+ if (i > sh->pd_idx)
+ i--;
+ break;
+ case ALGORITHM_LEFT_SYMMETRIC_6:
+ case ALGORITHM_RIGHT_SYMMETRIC_6:
+ if (i < sh->pd_idx)
+ i += data_disks + 1;
+ i -= (sh->pd_idx + 1);
+ break;
+ case ALGORITHM_PARITY_0_6:
+ i -= 1;
+ break;
+ default:
+ BUG();
+ }
+ break;
+ }
+
+ chunk_number = stripe * data_disks + i;
+ r_sector = chunk_number * sectors_per_chunk + chunk_offset;
+
+ check = raid5_compute_sector(conf, r_sector,
+ previous, &dummy1, &sh2);
+ if (check != sh->sector || dummy1 != dd_idx || sh2.pd_idx != sh->pd_idx
+ || sh2.qd_idx != sh->qd_idx) {
+ printk(KERN_ERR "md/raid:%s: compute_blocknr: map not correct\n",
+ mdname(conf->mddev));
+ return 0;
+ }
+ return r_sector;
+}
+
+static void
+schedule_reconstruction(struct stripe_head *sh, struct stripe_head_state *s,
+ int rcw, int expand)
+{
+ int i, pd_idx = sh->pd_idx, qd_idx = sh->qd_idx, disks = sh->disks;
+ struct r5conf *conf = sh->raid_conf;
+ int level = conf->level;
+
+ if (rcw) {
+
+ 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 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) {
+ if (!s->locked)
+ /* False alarm, nothing to do */
+ return;
+ 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_RECONSTRUCT, &s->ops_request);
+
+ if (s->locked + conf->max_degraded == disks)
+ if (!test_and_set_bit(STRIPE_FULL_WRITE, &sh->state))
+ atomic_inc(&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)));
+ BUG_ON(level == 6 &&
+ (!(test_bit(R5_UPTODATE, &sh->dev[qd_idx].flags) ||
+ test_bit(R5_Wantcompute, &sh->dev[qd_idx].flags))));
+
+ for (i = disks; i--; ) {
+ struct r5dev *dev = &sh->dev[i];
+ if (i == pd_idx || i == qd_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++;
+ }
+ }
+ if (!s->locked)
+ /* False alarm - nothing to do */
+ return;
+ 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_RECONSTRUCT, &s->ops_request);
+ }
+
+ /* keep the parity disk(s) 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++;
+
+ if (level == 6) {
+ int qd_idx = sh->qd_idx;
+ struct r5dev *dev = &sh->dev[qd_idx];
+
+ set_bit(R5_LOCKED, &dev->flags);
+ clear_bit(R5_UPTODATE, &dev->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, int previous)
+{
+ struct bio **bip;
+ struct r5conf *conf = sh->raid_conf;
+ int firstwrite=0;
+
+ pr_debug("adding bi b#%llu to stripe s#%llu\n",
+ (unsigned long long)bi->bi_iter.bi_sector,
+ (unsigned long long)sh->sector);
+
+ /*
+ * If several bio share a stripe. The bio bi_phys_segments acts as a
+ * reference count to avoid race. The reference count should already be
+ * increased before this function is called (for example, in
+ * make_request()), so other bio sharing this stripe will not free the
+ * stripe. If a stripe is owned by one stripe, the stripe lock will
+ * protect it.
+ */
+ spin_lock_irq(&sh->stripe_lock);
+ /* Don't allow new IO added to stripes in batch list */
+ if (sh->batch_head)
+ goto overlap;
+ if (forwrite) {
+ bip = &sh->dev[dd_idx].towrite;
+ if (*bip == NULL)
+ firstwrite = 1;
+ } else
+ bip = &sh->dev[dd_idx].toread;
+ while (*bip && (*bip)->bi_iter.bi_sector < bi->bi_iter.bi_sector) {
+ if (bio_end_sector(*bip) > bi->bi_iter.bi_sector)
+ goto overlap;
+ bip = & (*bip)->bi_next;
+ }
+ if (*bip && (*bip)->bi_iter.bi_sector < bio_end_sector(bi))
+ goto overlap;
+
+ if (!forwrite || previous)
+ clear_bit(STRIPE_BATCH_READY, &sh->state);
+
+ BUG_ON(*bip && bi->bi_next && (*bip) != bi->bi_next);
+ if (*bip)
+ bi->bi_next = *bip;
+ *bip = bi;
+ raid5_inc_bi_active_stripes(bi);
+
+ 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_iter.bi_sector <= sector;
+ bi = r5_next_bio(bi, sh->dev[dd_idx].sector)) {
+ if (bio_end_sector(bi) >= sector)
+ sector = bio_end_sector(bi);
+ }
+ if (sector >= sh->dev[dd_idx].sector + STRIPE_SECTORS)
+ if (!test_and_set_bit(R5_OVERWRITE, &sh->dev[dd_idx].flags))
+ sh->overwrite_disks++;
+ }
+
+ pr_debug("added bi b#%llu to stripe s#%llu, disk %d.\n",
+ (unsigned long long)(*bip)->bi_iter.bi_sector,
+ (unsigned long long)sh->sector, dd_idx);
+
+ if (conf->mddev->bitmap && firstwrite) {
+ /* Cannot hold spinlock over bitmap_startwrite,
+ * but must ensure this isn't added to a batch until
+ * we have added to the bitmap and set bm_seq.
+ * So set STRIPE_BITMAP_PENDING to prevent
+ * batching.
+ * If multiple add_stripe_bio() calls race here they
+ * much all set STRIPE_BITMAP_PENDING. So only the first one
+ * to complete "bitmap_startwrite" gets to set
+ * STRIPE_BIT_DELAY. This is important as once a stripe
+ * is added to a batch, STRIPE_BIT_DELAY cannot be changed
+ * any more.
+ */
+ set_bit(STRIPE_BITMAP_PENDING, &sh->state);
+ spin_unlock_irq(&sh->stripe_lock);
+ bitmap_startwrite(conf->mddev->bitmap, sh->sector,
+ STRIPE_SECTORS, 0);
+ spin_lock_irq(&sh->stripe_lock);
+ clear_bit(STRIPE_BITMAP_PENDING, &sh->state);
+ if (!sh->batch_head) {
+ sh->bm_seq = conf->seq_flush+1;
+ set_bit(STRIPE_BIT_DELAY, &sh->state);
+ }
+ }
+ spin_unlock_irq(&sh->stripe_lock);
+
+ if (stripe_can_batch(sh))
+ stripe_add_to_batch_list(conf, sh);
+ return 1;
+
+ overlap:
+ set_bit(R5_Overlap, &sh->dev[dd_idx].flags);
+ spin_unlock_irq(&sh->stripe_lock);
+ return 0;
+}
+
+static void end_reshape(struct r5conf *conf);
+
+static void stripe_set_idx(sector_t stripe, struct r5conf *conf, int previous,
+ struct stripe_head *sh)
+{
+ int sectors_per_chunk =
+ previous ? conf->prev_chunk_sectors : conf->chunk_sectors;
+ int dd_idx;
+ int chunk_offset = sector_div(stripe, sectors_per_chunk);
+ int disks = previous ? conf->previous_raid_disks : conf->raid_disks;
+
+ raid5_compute_sector(conf,
+ stripe * (disks - conf->max_degraded)
+ *sectors_per_chunk + chunk_offset,
+ previous,
+ &dd_idx, sh);
+}
+
+static void
+handle_failed_stripe(struct r5conf *conf, struct stripe_head *sh,
+ struct stripe_head_state *s, int disks,
+ struct bio **return_bi)
+{
+ int i;
+ BUG_ON(sh->batch_head);
+ for (i = disks; i--; ) {
+ struct bio *bi;
+ int bitmap_end = 0;
+
+ if (test_bit(R5_ReadError, &sh->dev[i].flags)) {
+ struct md_rdev *rdev;
+ rcu_read_lock();
+ rdev = rcu_dereference(conf->disks[i].rdev);
+ if (rdev && test_bit(In_sync, &rdev->flags))
+ atomic_inc(&rdev->nr_pending);
+ else
+ rdev = NULL;
+ rcu_read_unlock();
+ if (rdev) {
+ if (!rdev_set_badblocks(
+ rdev,
+ sh->sector,
+ STRIPE_SECTORS, 0))
+ md_error(conf->mddev, rdev);
+ rdev_dec_pending(rdev, conf->mddev);
+ }
+ }
+ spin_lock_irq(&sh->stripe_lock);
+ /* fail all writes first */
+ bi = sh->dev[i].towrite;
+ sh->dev[i].towrite = NULL;
+ sh->overwrite_disks = 0;
+ spin_unlock_irq(&sh->stripe_lock);
+ if (bi)
+ bitmap_end = 1;
+
+ if (test_and_clear_bit(R5_Overlap, &sh->dev[i].flags))
+ wake_up(&conf->wait_for_overlap);
+
+ while (bi && bi->bi_iter.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_active_stripes(bi)) {
+ md_write_end(conf->mddev);
+ bi->bi_next = *return_bi;
+ *return_bi = bi;
+ }
+ bi = nextbi;
+ }
+ if (bitmap_end)
+ bitmap_endwrite(conf->mddev->bitmap, sh->sector,
+ STRIPE_SECTORS, 0, 0);
+ bitmap_end = 0;
+ /* and fail all 'written' */
+ bi = sh->dev[i].written;
+ sh->dev[i].written = NULL;
+ if (test_and_clear_bit(R5_SkipCopy, &sh->dev[i].flags)) {
+ WARN_ON(test_bit(R5_UPTODATE, &sh->dev[i].flags));
+ sh->dev[i].page = sh->dev[i].orig_page;
+ }
+
+ if (bi) bitmap_end = 1;
+ while (bi && bi->bi_iter.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_active_stripes(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))) {
+ spin_lock_irq(&sh->stripe_lock);
+ bi = sh->dev[i].toread;
+ sh->dev[i].toread = NULL;
+ spin_unlock_irq(&sh->stripe_lock);
+ if (test_and_clear_bit(R5_Overlap, &sh->dev[i].flags))
+ wake_up(&conf->wait_for_overlap);
+ while (bi && bi->bi_iter.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_active_stripes(bi)) {
+ bi->bi_next = *return_bi;
+ *return_bi = bi;
+ }
+ bi = nextbi;
+ }
+ }
+ if (bitmap_end)
+ bitmap_endwrite(conf->mddev->bitmap, sh->sector,
+ STRIPE_SECTORS, 0, 0);
+ /* If we were in the middle of a write the parity block might
+ * still be locked - so just clear all R5_LOCKED flags
+ */
+ clear_bit(R5_LOCKED, &sh->dev[i].flags);
+ }
+
+ 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_failed_sync(struct r5conf *conf, struct stripe_head *sh,
+ struct stripe_head_state *s)
+{
+ int abort = 0;
+ int i;
+
+ BUG_ON(sh->batch_head);
+ clear_bit(STRIPE_SYNCING, &sh->state);
+ if (test_and_clear_bit(R5_Overlap, &sh->dev[sh->pd_idx].flags))
+ wake_up(&conf->wait_for_overlap);
+ s->syncing = 0;
+ s->replacing = 0;
+ /* There is nothing more to do for sync/check/repair.
+ * Don't even need to abort as that is handled elsewhere
+ * if needed, and not always wanted e.g. if there is a known
+ * bad block here.
+ * For recover/replace we need to record a bad block on all
+ * non-sync devices, or abort the recovery
+ */
+ if (test_bit(MD_RECOVERY_RECOVER, &conf->mddev->recovery)) {
+ /* During recovery devices cannot be removed, so
+ * locking and refcounting of rdevs is not needed
+ */
+ for (i = 0; i < conf->raid_disks; i++) {
+ struct md_rdev *rdev = conf->disks[i].rdev;
+ if (rdev
+ && !test_bit(Faulty, &rdev->flags)
+ && !test_bit(In_sync, &rdev->flags)
+ && !rdev_set_badblocks(rdev, sh->sector,
+ STRIPE_SECTORS, 0))
+ abort = 1;
+ rdev = conf->disks[i].replacement;
+ if (rdev
+ && !test_bit(Faulty, &rdev->flags)
+ && !test_bit(In_sync, &rdev->flags)
+ && !rdev_set_badblocks(rdev, sh->sector,
+ STRIPE_SECTORS, 0))
+ abort = 1;
+ }
+ if (abort)
+ conf->recovery_disabled =
+ conf->mddev->recovery_disabled;
+ }
+ md_done_sync(conf->mddev, STRIPE_SECTORS, !abort);
+}
+
+static int want_replace(struct stripe_head *sh, int disk_idx)
+{
+ struct md_rdev *rdev;
+ int rv = 0;
+ /* Doing recovery so rcu locking not required */
+ rdev = sh->raid_conf->disks[disk_idx].replacement;
+ if (rdev
+ && !test_bit(Faulty, &rdev->flags)
+ && !test_bit(In_sync, &rdev->flags)
+ && (rdev->recovery_offset <= sh->sector
+ || rdev->mddev->recovery_cp <= sh->sector))
+ rv = 1;
+
+ return rv;
+}
+
+/* fetch_block - 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_fill to continue
+ */
+
+static int need_this_block(struct stripe_head *sh, struct stripe_head_state *s,
+ int disk_idx, int disks)
+{
+ struct r5dev *dev = &sh->dev[disk_idx];
+ struct r5dev *fdev[2] = { &sh->dev[s->failed_num[0]],
+ &sh->dev[s->failed_num[1]] };
+ int i;
+
+
+ if (test_bit(R5_LOCKED, &dev->flags) ||
+ test_bit(R5_UPTODATE, &dev->flags))
+ /* No point reading this as we already have it or have
+ * decided to get it.
+ */
+ return 0;
+
+ if (dev->toread ||
+ (dev->towrite && !test_bit(R5_OVERWRITE, &dev->flags)))
+ /* We need this block to directly satisfy a request */
+ return 1;
+
+ if (s->syncing || s->expanding ||
+ (s->replacing && want_replace(sh, disk_idx)))
+ /* When syncing, or expanding we read everything.
+ * When replacing, we need the replaced block.
+ */
+ return 1;
+
+ if ((s->failed >= 1 && fdev[0]->toread) ||
+ (s->failed >= 2 && fdev[1]->toread))
+ /* If we want to read from a failed device, then
+ * we need to actually read every other device.
+ */
+ return 1;
+
+ /* Sometimes neither read-modify-write nor reconstruct-write
+ * cycles can work. In those cases we read every block we
+ * can. Then the parity-update is certain to have enough to
+ * work with.
+ * This can only be a problem when we need to write something,
+ * and some device has failed. If either of those tests
+ * fail we need look no further.
+ */
+ if (!s->failed || !s->to_write)
+ return 0;
+
+ if (test_bit(R5_Insync, &dev->flags) &&
+ !test_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
+ /* Pre-reads at not permitted until after short delay
+ * to gather multiple requests. However if this
+ * device is no Insync, the block could only be be computed
+ * and there is no need to delay that.
+ */
+ return 0;
+
+ for (i = 0; i < s->failed; i++) {
+ if (fdev[i]->towrite &&
+ !test_bit(R5_UPTODATE, &fdev[i]->flags) &&
+ !test_bit(R5_OVERWRITE, &fdev[i]->flags))
+ /* If we have a partial write to a failed
+ * device, then we will need to reconstruct
+ * the content of that device, so all other
+ * devices must be read.
+ */
+ return 1;
+ }
+
+ /* If we are forced to do a reconstruct-write, either because
+ * the current RAID6 implementation only supports that, or
+ * or because parity cannot be trusted and we are currently
+ * recovering it, there is extra need to be careful.
+ * If one of the devices that we would need to read, because
+ * it is not being overwritten (and maybe not written at all)
+ * is missing/faulty, then we need to read everything we can.
+ */
+ if (sh->raid_conf->level != 6 &&
+ sh->sector < sh->raid_conf->mddev->recovery_cp)
+ /* reconstruct-write isn't being forced */
+ return 0;
+ for (i = 0; i < s->failed; i++) {
+ if (s->failed_num[i] != sh->pd_idx &&
+ s->failed_num[i] != sh->qd_idx &&
+ !test_bit(R5_UPTODATE, &fdev[i]->flags) &&
+ !test_bit(R5_OVERWRITE, &fdev[i]->flags))
+ return 1;
+ }
+
+ return 0;
+}
+
+static int fetch_block(struct stripe_head *sh, struct stripe_head_state *s,
+ int disk_idx, int disks)
+{
+ struct r5dev *dev = &sh->dev[disk_idx];
+
+ /* is the data in this block needed, and can we get it? */
+ if (need_this_block(sh, s, disk_idx, disks)) {
+ /* we would like to get this block, possibly by computing it,
+ * otherwise read it if the backing disk is insync
+ */
+ BUG_ON(test_bit(R5_Wantcompute, &dev->flags));
+ BUG_ON(test_bit(R5_Wantread, &dev->flags));
+ BUG_ON(sh->batch_head);
+ if ((s->uptodate == disks - 1) &&
+ (s->failed && (disk_idx == s->failed_num[0] ||
+ disk_idx == s->failed_num[1]))) {
+ /* have disk failed, and we're requested to fetch it;
+ * do compute it
+ */
+ pr_debug("Computing stripe %llu block %d\n",
+ (unsigned long long)sh->sector, disk_idx);
+ 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;
+ sh->ops.target2 = -1; /* no 2nd target */
+ s->req_compute = 1;
+ /* Careful: from this point on 'uptodate' is in the eye
+ * of raid_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;
+ } 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 == disk_idx)
+ 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,
+ disk_idx, other);
+ set_bit(STRIPE_COMPUTE_RUN, &sh->state);
+ set_bit(STRIPE_OP_COMPUTE_BLK, &s->ops_request);
+ set_bit(R5_Wantcompute, &sh->dev[disk_idx].flags);
+ set_bit(R5_Wantcompute, &sh->dev[other].flags);
+ sh->ops.target = disk_idx;
+ sh->ops.target2 = other;
+ s->uptodate += 2;
+ s->req_compute = 1;
+ return 1;
+ } 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_fill - read or compute data to satisfy pending requests.
+ */
+static void handle_stripe_fill(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_block(sh, s, i, disks))
+ break;
+ set_bit(STRIPE_HANDLE, &sh->state);
+}
+
+static void break_stripe_batch_list(struct stripe_head *head_sh,
+ unsigned long handle_flags);
+/* 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(struct r5conf *conf,
+ struct stripe_head *sh, int disks, struct bio **return_bi)
+{
+ int i;
+ struct r5dev *dev;
+ int discard_pending = 0;
+ struct stripe_head *head_sh = sh;
+ bool do_endio = false;
+
+ 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) ||
+ test_bit(R5_Discard, &dev->flags) ||
+ test_bit(R5_SkipCopy, &dev->flags))) {
+ /* We can return any write requests */
+ struct bio *wbi, *wbi2;
+ pr_debug("Return write for disc %d\n", i);
+ if (test_and_clear_bit(R5_Discard, &dev->flags))
+ clear_bit(R5_UPTODATE, &dev->flags);
+ if (test_and_clear_bit(R5_SkipCopy, &dev->flags)) {
+ WARN_ON(test_bit(R5_UPTODATE, &dev->flags));
+ }
+ do_endio = true;
+
+returnbi:
+ dev->page = dev->orig_page;
+ wbi = dev->written;
+ dev->written = NULL;
+ while (wbi && wbi->bi_iter.bi_sector <
+ dev->sector + STRIPE_SECTORS) {
+ wbi2 = r5_next_bio(wbi, dev->sector);
+ if (!raid5_dec_bi_active_stripes(wbi)) {
+ md_write_end(conf->mddev);
+ wbi->bi_next = *return_bi;
+ *return_bi = wbi;
+ }
+ wbi = wbi2;
+ }
+ bitmap_endwrite(conf->mddev->bitmap, sh->sector,
+ STRIPE_SECTORS,
+ !test_bit(STRIPE_DEGRADED, &sh->state),
+ 0);
+ if (head_sh->batch_head) {
+ sh = list_first_entry(&sh->batch_list,
+ struct stripe_head,
+ batch_list);
+ if (sh != head_sh) {
+ dev = &sh->dev[i];
+ goto returnbi;
+ }
+ }
+ sh = head_sh;
+ dev = &sh->dev[i];
+ } else if (test_bit(R5_Discard, &dev->flags))
+ discard_pending = 1;
+ WARN_ON(test_bit(R5_SkipCopy, &dev->flags));
+ WARN_ON(dev->page != dev->orig_page);
+ }
+ if (!discard_pending &&
+ test_bit(R5_Discard, &sh->dev[sh->pd_idx].flags)) {
+ clear_bit(R5_Discard, &sh->dev[sh->pd_idx].flags);
+ clear_bit(R5_UPTODATE, &sh->dev[sh->pd_idx].flags);
+ if (sh->qd_idx >= 0) {
+ clear_bit(R5_Discard, &sh->dev[sh->qd_idx].flags);
+ clear_bit(R5_UPTODATE, &sh->dev[sh->qd_idx].flags);
+ }
+ /* now that discard is done we can proceed with any sync */
+ clear_bit(STRIPE_DISCARD, &sh->state);
+ /*
+ * SCSI discard will change some bio fields and the stripe has
+ * no updated data, so remove it from hash list and the stripe
+ * will be reinitialized
+ */
+ spin_lock_irq(&conf->device_lock);
+unhash:
+ remove_hash(sh);
+ if (head_sh->batch_head) {
+ sh = list_first_entry(&sh->batch_list,
+ struct stripe_head, batch_list);
+ if (sh != head_sh)
+ goto unhash;
+ }
+ spin_unlock_irq(&conf->device_lock);
+ sh = head_sh;
+
+ if (test_bit(STRIPE_SYNC_REQUESTED, &sh->state))
+ set_bit(STRIPE_HANDLE, &sh->state);
+
+ }
+
+ 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);
+
+ if (head_sh->batch_head && do_endio)
+ break_stripe_batch_list(head_sh, STRIPE_EXPAND_SYNC_FLAGS);
+}
+
+static void handle_stripe_dirtying(struct r5conf *conf,
+ struct stripe_head *sh,
+ struct stripe_head_state *s,
+ int disks)
+{
+ int rmw = 0, rcw = 0, i;
+ sector_t recovery_cp = conf->mddev->recovery_cp;
+
+ /* Check whether resync is now happening or should start.
+ * If yes, then the array is dirty (after unclean shutdown or
+ * initial creation), so parity in some stripes might be inconsistent.
+ * In this case, we need to always do reconstruct-write, to ensure
+ * that in case of drive failure or read-error correction, we
+ * generate correct data from the parity.
+ */
+ if (conf->rmw_level == PARITY_DISABLE_RMW ||
+ (recovery_cp < MaxSector && sh->sector >= recovery_cp &&
+ s->failed == 0)) {
+ /* Calculate the real rcw later - for now make it
+ * look like rcw is cheaper
+ */
+ rcw = 1; rmw = 2;
+ pr_debug("force RCW rmw_level=%u, recovery_cp=%llu sh->sector=%llu\n",
+ conf->rmw_level, (unsigned long long)recovery_cp,
+ (unsigned long long)sh->sector);
+ } else for (i = disks; i--; ) {
+ /* would I have to read this buffer for read_modify_write */
+ struct r5dev *dev = &sh->dev[i];
+ if ((dev->towrite || i == sh->pd_idx || i == sh->qd_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 && i != sh->qd_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 == rcw && conf->rmw_level == PARITY_ENABLE_RMW)) && rmw > 0) {
+ /* prefer read-modify-write, but need to get some data */
+ if (conf->mddev->queue)
+ blk_add_trace_msg(conf->mddev->queue,
+ "raid5 rmw %llu %d",
+ (unsigned long long)sh->sector, rmw);
+ for (i = disks; i--; ) {
+ struct r5dev *dev = &sh->dev[i];
+ if ((dev->towrite || i == sh->pd_idx || i == sh->qd_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 == rmw && conf->rmw_level != PARITY_ENABLE_RMW)) && rcw > 0) {
+ /* want reconstruct write, but need to get some data */
+ int qread =0;
+ rcw = 0;
+ for (i = disks; i--; ) {
+ struct r5dev *dev = &sh->dev[i];
+ if (!test_bit(R5_OVERWRITE, &dev->flags) &&
+ i != sh->pd_idx && i != sh->qd_idx &&
+ !test_bit(R5_LOCKED, &dev->flags) &&
+ !(test_bit(R5_UPTODATE, &dev->flags) ||
+ test_bit(R5_Wantcompute, &dev->flags))) {
+ rcw++;
+ if (test_bit(R5_Insync, &dev->flags) &&
+ 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++;
+ qread++;
+ } else {
+ set_bit(STRIPE_DELAYED, &sh->state);
+ set_bit(STRIPE_HANDLE, &sh->state);
+ }
+ }
+ }
+ if (rcw && conf->mddev->queue)
+ blk_add_trace_msg(conf->mddev->queue, "raid5 rcw %llu %d %d %d",
+ (unsigned long long)sh->sector,
+ rcw, qread, test_bit(STRIPE_DELAYED, &sh->state));
+ }
+
+ if (rcw > disks && rmw > disks &&
+ !test_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
+ set_bit(STRIPE_DELAYED, &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. raid_run_ops only
+ * handles the case where compute block and reconstruct 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_reconstruction(sh, s, rcw == 0, 0);
+}
+
+static void handle_parity_checks5(struct r5conf *conf, struct stripe_head *sh,
+ struct stripe_head_state *s, int disks)
+{
+ struct r5dev *dev = NULL;
+
+ BUG_ON(sh->batch_head);
+ 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[0]];
+ /* 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 & SUM_CHECK_P_RESULT) == 0)
+ /* parity is correct (on disc,
+ * not in buffer any more)
+ */
+ set_bit(STRIPE_INSYNC, &sh->state);
+ else {
+ atomic64_add(STRIPE_SECTORS, &conf->mddev->resync_mismatches);
+ 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;
+ sh->ops.target2 = -1;
+ 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(struct r5conf *conf, struct stripe_head *sh,
+ struct stripe_head_state *s,
+ int disks)
+{
+ int pd_idx = sh->pd_idx;
+ int qd_idx = sh->qd_idx;
+ struct r5dev *dev;
+
+ BUG_ON(sh->batch_head);
+ set_bit(STRIPE_HANDLE, &sh->state);
+
+ BUG_ON(s->failed > 2);
+
+ /* 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
+ */
+
+ switch (sh->check_state) {
+ case check_state_idle:
+ /* start a new check operation if there are < 2 failures */
+ if (s->failed == s->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).
+ */
+ sh->check_state = check_state_run;
+ }
+ if (!s->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
+ */
+ if (sh->check_state == check_state_run)
+ sh->check_state = check_state_run_pq;
+ else
+ sh->check_state = check_state_run_q;
+ }
+
+ /* discard potentially stale zero_sum_result */
+ sh->ops.zero_sum_result = 0;
+
+ if (sh->check_state == check_state_run) {
+ /* async_xor_zero_sum destroys the contents of P */
+ clear_bit(R5_UPTODATE, &sh->dev[pd_idx].flags);
+ s->uptodate--;
+ }
+ if (sh->check_state >= check_state_run &&
+ sh->check_state <= check_state_run_pq) {
+ /* async_syndrome_zero_sum preserves P and Q, so
+ * no need to mark them !uptodate here
+ */
+ set_bit(STRIPE_OP_CHECK, &s->ops_request);
+ break;
+ }
+
+ /* we have 2-disk failure */
+ BUG_ON(s->failed != 2);
+ /* fall through */
+ case check_state_compute_result:
+ sh->check_state = check_state_idle;
+
+ /* check that a write has not made the stripe insync */
+ if (test_bit(STRIPE_INSYNC, &sh->state))
+ break;
+
+ /* now write out any block on a failed drive,
+ * or P or Q if they were recomputed
+ */
+ BUG_ON(s->uptodate < disks - 1); /* We don't need Q to recover */
+ if (s->failed == 2) {
+ dev = &sh->dev[s->failed_num[1]];
+ s->locked++;
+ set_bit(R5_LOCKED, &dev->flags);
+ set_bit(R5_Wantwrite, &dev->flags);
+ }
+ if (s->failed >= 1) {
+ dev = &sh->dev[s->failed_num[0]];
+ s->locked++;
+ set_bit(R5_LOCKED, &dev->flags);
+ set_bit(R5_Wantwrite, &dev->flags);
+ }
+ if (sh->ops.zero_sum_result & SUM_CHECK_P_RESULT) {
+ dev = &sh->dev[pd_idx];
+ s->locked++;
+ set_bit(R5_LOCKED, &dev->flags);
+ set_bit(R5_Wantwrite, &dev->flags);
+ }
+ if (sh->ops.zero_sum_result & SUM_CHECK_Q_RESULT) {
+ 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);
+ break;
+ case check_state_run:
+ case check_state_run_q:
+ case check_state_run_pq:
+ break; /* we will be called again upon completion */
+ case check_state_check_result:
+ sh->check_state = check_state_idle;
+
+ /* 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) {
+ /* both parities are correct */
+ if (!s->failed)
+ set_bit(STRIPE_INSYNC, &sh->state);
+ else {
+ /* in contrast to the raid5 case we can validate
+ * parity, but still have a failure to write
+ * back
+ */
+ sh->check_state = check_state_compute_result;
+ /* Returning at this point means that we may go
+ * off and bring p and/or q uptodate again so
+ * we make sure to check zero_sum_result again
+ * to verify if p or q need writeback
+ */
+ }
+ } else {
+ atomic64_add(STRIPE_SECTORS, &conf->mddev->resync_mismatches);
+ if (test_bit(MD_RECOVERY_CHECK, &conf->mddev->recovery))
+ /* don't try to repair!! */
+ set_bit(STRIPE_INSYNC, &sh->state);
+ else {
+ int *target = &sh->ops.target;
+
+ sh->ops.target = -1;
+ sh->ops.target2 = -1;
+ sh->check_state = check_state_compute_run;
+ set_bit(STRIPE_COMPUTE_RUN, &sh->state);
+ set_bit(STRIPE_OP_COMPUTE_BLK, &s->ops_request);
+ if (sh->ops.zero_sum_result & SUM_CHECK_P_RESULT) {
+ set_bit(R5_Wantcompute,
+ &sh->dev[pd_idx].flags);
+ *target = pd_idx;
+ target = &sh->ops.target2;
+ s->uptodate++;
+ }
+ if (sh->ops.zero_sum_result & SUM_CHECK_Q_RESULT) {
+ set_bit(R5_Wantcompute,
+ &sh->dev[qd_idx].flags);
+ *target = qd_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_stripe_expansion(struct r5conf *conf, struct stripe_head *sh)
+{
+ 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;
+ BUG_ON(sh->batch_head);
+ clear_bit(STRIPE_EXPAND_SOURCE, &sh->state);
+ for (i = 0; i < sh->disks; i++)
+ if (i != sh->pd_idx && i != sh->qd_idx) {
+ int dd_idx, j;
+ struct stripe_head *sh2;
+ struct async_submit_ctl submit;
+
+ sector_t bn = compute_blocknr(sh, i, 1);
+ sector_t s = raid5_compute_sector(conf, bn, 0,
+ &dd_idx, NULL);
+ sh2 = get_active_stripe(conf, s, 0, 1, 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 */
+ init_async_submit(&submit, 0, tx, NULL, NULL, NULL);
+ tx = async_memcpy(sh2->dev[dd_idx].page,
+ sh->dev[i].page, 0, 0, STRIPE_SIZE,
+ &submit);
+
+ 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 &&
+ j != sh2->qd_idx &&
+ !test_bit(R5_Expanded, &sh2->dev[j].flags))
+ break;
+ if (j == conf->raid_disks) {
+ set_bit(STRIPE_EXPAND_READY, &sh2->state);
+ set_bit(STRIPE_HANDLE, &sh2->state);
+ }
+ release_stripe(sh2);
+
+ }
+ /* done submitting copies, wait for them to complete */
+ async_tx_quiesce(&tx);
+}
+
+/*
+ * handle_stripe - do things to a stripe.
+ *
+ * We lock the stripe by setting STRIPE_ACTIVE and then examine the
+ * state of various bits to see what needs to be done.
+ * Possible results:
+ * return some read requests which now have data
+ * return some write requests which are safely on storage
+ * schedule a read on some buffers
+ * schedule a write of some buffers
+ * return confirmation of parity correctness
+ *
+ */
+
+static void analyse_stripe(struct stripe_head *sh, struct stripe_head_state *s)
+{
+ struct r5conf *conf = sh->raid_conf;
+ int disks = sh->disks;
+ struct r5dev *dev;
+ int i;
+ int do_recovery = 0;
+
+ memset(s, 0, sizeof(*s));
+
+ s->expanding = test_bit(STRIPE_EXPAND_SOURCE, &sh->state) && !sh->batch_head;
+ s->expanded = test_bit(STRIPE_EXPAND_READY, &sh->state) && !sh->batch_head;
+ s->failed_num[0] = -1;
+ s->failed_num[1] = -1;
+
+ /* Now to look around and see what can be done */
+ rcu_read_lock();
+ for (i=disks; i--; ) {
+ struct md_rdev *rdev;
+ sector_t first_bad;
+ int bad_sectors;
+ int is_bad = 0;
+
+ dev = &sh->dev[i];
+
+ 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
+ *
+ * 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++;
+ BUG_ON(s->compute > 2);
+ }
+
+ 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++;
+ /* Prefer to use the replacement for reads, but only
+ * if it is recovered enough and has no bad blocks.
+ */
+ rdev = rcu_dereference(conf->disks[i].replacement);
+ if (rdev && !test_bit(Faulty, &rdev->flags) &&
+ rdev->recovery_offset >= sh->sector + STRIPE_SECTORS &&
+ !is_badblock(rdev, sh->sector, STRIPE_SECTORS,
+ &first_bad, &bad_sectors))
+ set_bit(R5_ReadRepl, &dev->flags);
+ else {
+ if (rdev)
+ set_bit(R5_NeedReplace, &dev->flags);
+ rdev = rcu_dereference(conf->disks[i].rdev);
+ clear_bit(R5_ReadRepl, &dev->flags);
+ }
+ if (rdev && test_bit(Faulty, &rdev->flags))
+ rdev = NULL;
+ if (rdev) {
+ is_bad = is_badblock(rdev, sh->sector, STRIPE_SECTORS,
+ &first_bad, &bad_sectors);
+ if (s->blocked_rdev == NULL
+ && (test_bit(Blocked, &rdev->flags)
+ || is_bad < 0)) {
+ if (is_bad < 0)
+ set_bit(BlockedBadBlocks,
+ &rdev->flags);
+ s->blocked_rdev = rdev;
+ atomic_inc(&rdev->nr_pending);
+ }
+ }
+ clear_bit(R5_Insync, &dev->flags);
+ if (!rdev)
+ /* Not in-sync */;
+ else if (is_bad) {
+ /* also not in-sync */
+ if (!test_bit(WriteErrorSeen, &rdev->flags) &&
+ test_bit(R5_UPTODATE, &dev->flags)) {
+ /* treat as in-sync, but with a read error
+ * which we can now try to correct
+ */
+ set_bit(R5_Insync, &dev->flags);
+ set_bit(R5_ReadError, &dev->flags);
+ }
+ } else if (test_bit(In_sync, &rdev->flags))
+ set_bit(R5_Insync, &dev->flags);
+ else if (sh->sector + STRIPE_SECTORS <= rdev->recovery_offset)
+ /* in sync if before recovery_offset */
+ set_bit(R5_Insync, &dev->flags);
+ else if (test_bit(R5_UPTODATE, &dev->flags) &&
+ test_bit(R5_Expanded, &dev->flags))
+ /* If we've reshaped into here, we assume it is Insync.
+ * We will shortly update recovery_offset to make
+ * it official.
+ */
+ set_bit(R5_Insync, &dev->flags);
+
+ if (test_bit(R5_WriteError, &dev->flags)) {
+ /* This flag does not apply to '.replacement'
+ * only to .rdev, so make sure to check that*/
+ struct md_rdev *rdev2 = rcu_dereference(
+ conf->disks[i].rdev);
+ if (rdev2 == rdev)
+ clear_bit(R5_Insync, &dev->flags);
+ if (rdev2 && !test_bit(Faulty, &rdev2->flags)) {
+ s->handle_bad_blocks = 1;
+ atomic_inc(&rdev2->nr_pending);
+ } else
+ clear_bit(R5_WriteError, &dev->flags);
+ }
+ if (test_bit(R5_MadeGood, &dev->flags)) {
+ /* This flag does not apply to '.replacement'
+ * only to .rdev, so make sure to check that*/
+ struct md_rdev *rdev2 = rcu_dereference(
+ conf->disks[i].rdev);
+ if (rdev2 && !test_bit(Faulty, &rdev2->flags)) {
+ s->handle_bad_blocks = 1;
+ atomic_inc(&rdev2->nr_pending);
+ } else
+ clear_bit(R5_MadeGood, &dev->flags);
+ }
+ if (test_bit(R5_MadeGoodRepl, &dev->flags)) {
+ struct md_rdev *rdev2 = rcu_dereference(
+ conf->disks[i].replacement);
+ if (rdev2 && !test_bit(Faulty, &rdev2->flags)) {
+ s->handle_bad_blocks = 1;
+ atomic_inc(&rdev2->nr_pending);
+ } else
+ clear_bit(R5_MadeGoodRepl, &dev->flags);
+ }
+ if (!test_bit(R5_Insync, &dev->flags)) {
+ /* The ReadError flag will just be confusing now */
+ clear_bit(R5_ReadError, &dev->flags);
+ clear_bit(R5_ReWrite, &dev->flags);
+ }
+ if (test_bit(R5_ReadError, &dev->flags))
+ clear_bit(R5_Insync, &dev->flags);
+ if (!test_bit(R5_Insync, &dev->flags)) {
+ if (s->failed < 2)
+ s->failed_num[s->failed] = i;
+ s->failed++;
+ if (rdev && !test_bit(Faulty, &rdev->flags))
+ do_recovery = 1;
+ }
+ }
+ if (test_bit(STRIPE_SYNCING, &sh->state)) {
+ /* If there is a failed device being replaced,
+ * we must be recovering.
+ * else if we are after recovery_cp, we must be syncing
+ * else if MD_RECOVERY_REQUESTED is set, we also are syncing.
+ * else we can only be replacing
+ * sync and recovery both need to read all devices, and so
+ * use the same flag.
+ */
+ if (do_recovery ||
+ sh->sector >= conf->mddev->recovery_cp ||
+ test_bit(MD_RECOVERY_REQUESTED, &(conf->mddev->recovery)))
+ s->syncing = 1;
+ else
+ s->replacing = 1;
+ }
+ rcu_read_unlock();
+}
+
+static int clear_batch_ready(struct stripe_head *sh)
+{
+ /* Return '1' if this is a member of batch, or
+ * '0' if it is a lone stripe or a head which can now be
+ * handled.
+ */
+ struct stripe_head *tmp;
+ if (!test_and_clear_bit(STRIPE_BATCH_READY, &sh->state))
+ return (sh->batch_head && sh->batch_head != sh);
+ spin_lock(&sh->stripe_lock);
+ if (!sh->batch_head) {
+ spin_unlock(&sh->stripe_lock);
+ return 0;
+ }
+
+ /*
+ * this stripe could be added to a batch list before we check
+ * BATCH_READY, skips it
+ */
+ if (sh->batch_head != sh) {
+ spin_unlock(&sh->stripe_lock);
+ return 1;
+ }
+ spin_lock(&sh->batch_lock);
+ list_for_each_entry(tmp, &sh->batch_list, batch_list)
+ clear_bit(STRIPE_BATCH_READY, &tmp->state);
+ spin_unlock(&sh->batch_lock);
+ spin_unlock(&sh->stripe_lock);
+
+ /*
+ * BATCH_READY is cleared, no new stripes can be added.
+ * batch_list can be accessed without lock
+ */
+ return 0;
+}
+
+static void break_stripe_batch_list(struct stripe_head *head_sh,
+ unsigned long handle_flags)
+{
+ struct stripe_head *sh, *next;
+ int i;
+ int do_wakeup = 0;
+
+ list_for_each_entry_safe(sh, next, &head_sh->batch_list, batch_list) {
+
+ list_del_init(&sh->batch_list);
+
+ WARN_ON_ONCE(sh->state & ((1 << STRIPE_ACTIVE) |
+ (1 << STRIPE_SYNCING) |
+ (1 << STRIPE_REPLACED) |
+ (1 << STRIPE_PREREAD_ACTIVE) |
+ (1 << STRIPE_DELAYED) |
+ (1 << STRIPE_BIT_DELAY) |
+ (1 << STRIPE_FULL_WRITE) |
+ (1 << STRIPE_BIOFILL_RUN) |
+ (1 << STRIPE_COMPUTE_RUN) |
+ (1 << STRIPE_OPS_REQ_PENDING) |
+ (1 << STRIPE_DISCARD) |
+ (1 << STRIPE_BATCH_READY) |
+ (1 << STRIPE_BATCH_ERR) |
+ (1 << STRIPE_BITMAP_PENDING)));
+ WARN_ON_ONCE(head_sh->state & ((1 << STRIPE_DISCARD) |
+ (1 << STRIPE_REPLACED)));
+
+ set_mask_bits(&sh->state, ~(STRIPE_EXPAND_SYNC_FLAGS |
+ (1 << STRIPE_DEGRADED)),
+ head_sh->state & (1 << STRIPE_INSYNC));
+
+ sh->check_state = head_sh->check_state;
+ sh->reconstruct_state = head_sh->reconstruct_state;
+ for (i = 0; i < sh->disks; i++) {
+ if (test_and_clear_bit(R5_Overlap, &sh->dev[i].flags))
+ do_wakeup = 1;
+ sh->dev[i].flags = head_sh->dev[i].flags &
+ (~((1 << R5_WriteError) | (1 << R5_Overlap)));
+ }
+ spin_lock_irq(&sh->stripe_lock);
+ sh->batch_head = NULL;
+ spin_unlock_irq(&sh->stripe_lock);
+ if (handle_flags == 0 ||
+ sh->state & handle_flags)
+ set_bit(STRIPE_HANDLE, &sh->state);
+ release_stripe(sh);
+ }
+ spin_lock_irq(&head_sh->stripe_lock);
+ head_sh->batch_head = NULL;
+ spin_unlock_irq(&head_sh->stripe_lock);
+ for (i = 0; i < head_sh->disks; i++)
+ if (test_and_clear_bit(R5_Overlap, &head_sh->dev[i].flags))
+ do_wakeup = 1;
+ if (head_sh->state & handle_flags)
+ set_bit(STRIPE_HANDLE, &head_sh->state);
+
+ if (do_wakeup)
+ wake_up(&head_sh->raid_conf->wait_for_overlap);
+}
+
+static void handle_stripe(struct stripe_head *sh)
+{
+ struct stripe_head_state s;
+ struct r5conf *conf = sh->raid_conf;
+ int i;
+ int prexor;
+ int disks = sh->disks;
+ struct r5dev *pdev, *qdev;
+
+ clear_bit(STRIPE_HANDLE, &sh->state);
+ if (test_and_set_bit_lock(STRIPE_ACTIVE, &sh->state)) {
+ /* already being handled, ensure it gets handled
+ * again when current action finishes */
+ set_bit(STRIPE_HANDLE, &sh->state);
+ return;
+ }
+
+ if (clear_batch_ready(sh) ) {
+ clear_bit_unlock(STRIPE_ACTIVE, &sh->state);
+ return;
+ }
+
+ if (test_and_clear_bit(STRIPE_BATCH_ERR, &sh->state))
+ break_stripe_batch_list(sh, 0);
+
+ if (test_bit(STRIPE_SYNC_REQUESTED, &sh->state) && !sh->batch_head) {
+ spin_lock(&sh->stripe_lock);
+ /* Cannot process 'sync' concurrently with 'discard' */
+ if (!test_bit(STRIPE_DISCARD, &sh->state) &&
+ test_and_clear_bit(STRIPE_SYNC_REQUESTED, &sh->state)) {
+ set_bit(STRIPE_SYNCING, &sh->state);
+ clear_bit(STRIPE_INSYNC, &sh->state);
+ clear_bit(STRIPE_REPLACED, &sh->state);
+ }
+ spin_unlock(&sh->stripe_lock);
+ }
+ clear_bit(STRIPE_DELAYED, &sh->state);
+
+ pr_debug("handling stripe %llu, state=%#lx cnt=%d, "
+ "pd_idx=%d, qd_idx=%d\n, check:%d, reconstruct:%d\n",
+ (unsigned long long)sh->sector, sh->state,
+ atomic_read(&sh->count), sh->pd_idx, sh->qd_idx,
+ sh->check_state, sh->reconstruct_state);
+
+ analyse_stripe(sh, &s);
+
+ if (s.handle_bad_blocks) {
+ set_bit(STRIPE_HANDLE, &sh->state);
+ goto finish;
+ }
+
+ if (unlikely(s.blocked_rdev)) {
+ if (s.syncing || s.expanding || s.expanded ||
+ s.replacing || s.to_write || s.written) {
+ set_bit(STRIPE_HANDLE, &sh->state);
+ goto finish;
+ }
+ /* There is nothing for the blocked_rdev to block */
+ rdev_dec_pending(s.blocked_rdev, conf->mddev);
+ s.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,%d\n",
+ s.locked, s.uptodate, s.to_read, s.to_write, s.failed,
+ s.failed_num[0], s.failed_num[1]);
+ /* check if the array has lost more than max_degraded devices and,
+ * if so, some requests might need to be failed.
+ */
+ if (s.failed > conf->max_degraded) {
+ sh->check_state = 0;
+ sh->reconstruct_state = 0;
+ break_stripe_batch_list(sh, 0);
+ if (s.to_read+s.to_write+s.written)
+ handle_failed_stripe(conf, sh, &s, disks, &s.return_bi);
+ if (s.syncing + s.replacing)
+ handle_failed_sync(conf, sh, &s);
+ }
+
+ /* 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) &&
+ !test_bit(R5_Discard, &sh->dev[sh->pd_idx].flags));
+ BUG_ON(sh->qd_idx >= 0 &&
+ !test_bit(R5_UPTODATE, &sh->dev[sh->qd_idx].flags) &&
+ !test_bit(R5_Discard, &sh->dev[sh->qd_idx].flags));
+ for (i = disks; i--; ) {
+ struct r5dev *dev = &sh->dev[i];
+ if (test_bit(R5_LOCKED, &dev->flags) &&
+ (i == sh->pd_idx || i == sh->qd_idx ||
+ dev->written)) {
+ pr_debug("Writing block %d\n", i);
+ set_bit(R5_Wantwrite, &dev->flags);
+ if (prexor)
+ continue;
+ if (s.failed > 1)
+ continue;
+ if (!test_bit(R5_Insync, &dev->flags) ||
+ ((i == sh->pd_idx || i == sh->qd_idx) &&
+ s.failed == 0))
+ set_bit(STRIPE_INSYNC, &sh->state);
+ }
+ }
+ if (test_and_clear_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
+ s.dec_preread_active = 1;
+ }
+
+ /*
+ * might be able to return some write requests if the parity blocks
+ * are safe, or on a failed drive
+ */
+ pdev = &sh->dev[sh->pd_idx];
+ s.p_failed = (s.failed >= 1 && s.failed_num[0] == sh->pd_idx)
+ || (s.failed >= 2 && s.failed_num[1] == sh->pd_idx);
+ qdev = &sh->dev[sh->qd_idx];
+ s.q_failed = (s.failed >= 1 && s.failed_num[0] == sh->qd_idx)
+ || (s.failed >= 2 && s.failed_num[1] == sh->qd_idx)
+ || conf->level < 6;
+
+ if (s.written &&
+ (s.p_failed || ((test_bit(R5_Insync, &pdev->flags)
+ && !test_bit(R5_LOCKED, &pdev->flags)
+ && (test_bit(R5_UPTODATE, &pdev->flags) ||
+ test_bit(R5_Discard, &pdev->flags))))) &&
+ (s.q_failed || ((test_bit(R5_Insync, &qdev->flags)
+ && !test_bit(R5_LOCKED, &qdev->flags)
+ && (test_bit(R5_UPTODATE, &qdev->flags) ||
+ test_bit(R5_Discard, &qdev->flags))))))
+ handle_stripe_clean_event(conf, sh, disks, &s.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
+ || (conf->level == 6 && s.to_write && s.failed)
+ || (s.syncing && (s.uptodate + s.compute < disks))
+ || s.replacing
+ || s.expanding)
+ handle_stripe_fill(sh, &s, disks);
+
+ /* 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_dirtying(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))) {
+ if (conf->level == 6)
+ handle_parity_checks6(conf, sh, &s, disks);
+ else
+ handle_parity_checks5(conf, sh, &s, disks);
+ }
+
+ if ((s.replacing || s.syncing) && s.locked == 0
+ && !test_bit(STRIPE_COMPUTE_RUN, &sh->state)
+ && !test_bit(STRIPE_REPLACED, &sh->state)) {
+ /* Write out to replacement devices where possible */
+ for (i = 0; i < conf->raid_disks; i++)
+ if (test_bit(R5_NeedReplace, &sh->dev[i].flags)) {
+ WARN_ON(!test_bit(R5_UPTODATE, &sh->dev[i].flags));
+ set_bit(R5_WantReplace, &sh->dev[i].flags);
+ set_bit(R5_LOCKED, &sh->dev[i].flags);
+ s.locked++;
+ }
+ if (s.replacing)
+ set_bit(STRIPE_INSYNC, &sh->state);
+ set_bit(STRIPE_REPLACED, &sh->state);
+ }
+ if ((s.syncing || s.replacing) && s.locked == 0 &&
+ !test_bit(STRIPE_COMPUTE_RUN, &sh->state) &&
+ test_bit(STRIPE_INSYNC, &sh->state)) {
+ md_done_sync(conf->mddev, STRIPE_SECTORS, 1);
+ clear_bit(STRIPE_SYNCING, &sh->state);
+ if (test_and_clear_bit(R5_Overlap, &sh->dev[sh->pd_idx].flags))
+ wake_up(&conf->wait_for_overlap);
+ }
+
+ /* If the failed drives are just a ReadError, then we might need
+ * to progress the repair/check process
+ */
+ if (s.failed <= conf->max_degraded && !conf->mddev->ro)
+ for (i = 0; i < s.failed; i++) {
+ struct r5dev *dev = &sh->dev[s.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);
+ s.locked++;
+ } else {
+ /* let's read it back */
+ set_bit(R5_Wantread, &dev->flags);
+ set_bit(R5_LOCKED, &dev->flags);
+ s.locked++;
+ }
+ }
+ }
+
+ /* Finish reconstruct operations initiated by the expansion process */
+ if (sh->reconstruct_state == reconstruct_state_result) {
+ struct stripe_head *sh_src
+ = get_active_stripe(conf, sh->sector, 1, 1, 1);
+ if (sh_src && test_bit(STRIPE_EXPAND_SOURCE, &sh_src->state)) {
+ /* sh cannot be written until sh_src has been read.
+ * so arrange for sh to be delayed a little
+ */
+ set_bit(STRIPE_DELAYED, &sh->state);
+ set_bit(STRIPE_HANDLE, &sh->state);
+ if (!test_and_set_bit(STRIPE_PREREAD_ACTIVE,
+ &sh_src->state))
+ atomic_inc(&conf->preread_active_stripes);
+ release_stripe(sh_src);
+ goto finish;
+ }
+ if (sh_src)
+ release_stripe(sh_src);
+
+ sh->reconstruct_state = reconstruct_state_idle;
+ clear_bit(STRIPE_EXPANDING, &sh->state);
+ for (i = conf->raid_disks; i--; ) {
+ set_bit(R5_Wantwrite, &sh->dev[i].flags);
+ set_bit(R5_LOCKED, &sh->dev[i].flags);
+ s.locked++;
+ }
+ }
+
+ if (s.expanded && test_bit(STRIPE_EXPANDING, &sh->state) &&
+ !sh->reconstruct_state) {
+ /* Need to write out all blocks after computing parity */
+ sh->disks = conf->raid_disks;
+ stripe_set_idx(sh->sector, conf, 0, sh);
+ schedule_reconstruction(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);
+
+finish:
+ /* wait for this device to become unblocked */
+ if (unlikely(s.blocked_rdev)) {
+ if (conf->mddev->external)
+ md_wait_for_blocked_rdev(s.blocked_rdev,
+ conf->mddev);
+ else
+ /* Internal metadata will immediately
+ * be written by raid5d, so we don't
+ * need to wait here.
+ */
+ rdev_dec_pending(s.blocked_rdev,
+ conf->mddev);
+ }
+
+ if (s.handle_bad_blocks)
+ for (i = disks; i--; ) {
+ struct md_rdev *rdev;
+ struct r5dev *dev = &sh->dev[i];
+ if (test_and_clear_bit(R5_WriteError, &dev->flags)) {
+ /* We own a safe reference to the rdev */
+ rdev = conf->disks[i].rdev;
+ if (!rdev_set_badblocks(rdev, sh->sector,
+ STRIPE_SECTORS, 0))
+ md_error(conf->mddev, rdev);
+ rdev_dec_pending(rdev, conf->mddev);
+ }
+ if (test_and_clear_bit(R5_MadeGood, &dev->flags)) {
+ rdev = conf->disks[i].rdev;
+ rdev_clear_badblocks(rdev, sh->sector,
+ STRIPE_SECTORS, 0);
+ rdev_dec_pending(rdev, conf->mddev);
+ }
+ if (test_and_clear_bit(R5_MadeGoodRepl, &dev->flags)) {
+ rdev = conf->disks[i].replacement;
+ if (!rdev)
+ /* rdev have been moved down */
+ rdev = conf->disks[i].rdev;
+ rdev_clear_badblocks(rdev, sh->sector,
+ STRIPE_SECTORS, 0);
+ rdev_dec_pending(rdev, conf->mddev);
+ }
+ }
+
+ if (s.ops_request)
+ raid_run_ops(sh, s.ops_request);
+
+ ops_run_io(sh, &s);
+
+ if (s.dec_preread_active) {
+ /* We delay this until after ops_run_io so that if make_request
+ * is waiting on a flush, it won't continue until the writes
+ * have actually been submitted.
+ */
+ atomic_dec(&conf->preread_active_stripes);
+ if (atomic_read(&conf->preread_active_stripes) <
+ IO_THRESHOLD)
+ md_wakeup_thread(conf->mddev->thread);
+ }
+
+ return_io(s.return_bi);
+
+ clear_bit_unlock(STRIPE_ACTIVE, &sh->state);
+}
+
+static void raid5_activate_delayed(struct r5conf *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);
+ raid5_wakeup_stripe_thread(sh);
+ }
+ }
+}
+
+static void activate_bit_delay(struct r5conf *conf,
+ struct list_head *temp_inactive_list)
+{
+ /* 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);
+ int hash;
+ list_del_init(&sh->lru);
+ atomic_inc(&sh->count);
+ hash = sh->hash_lock_index;
+ __release_stripe(conf, sh, &temp_inactive_list[hash]);
+ }
+}
+
+static int raid5_congested(struct mddev *mddev, int bits)
+{
+ struct r5conf *conf = mddev->private;
+
+ /* No difference between reads and writes. Just check
+ * how busy the stripe_cache is
+ */
+
+ if (test_bit(R5_INACTIVE_BLOCKED, &conf->cache_state))
+ return 1;
+ if (conf->quiesce)
+ return 1;
+ if (atomic_read(&conf->empty_inactive_list_nr))
+ 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 mddev *mddev,
+ struct bvec_merge_data *bvm,
+ struct bio_vec *biovec)
+{
+ sector_t sector = bvm->bi_sector + get_start_sect(bvm->bi_bdev);
+ int max;
+ unsigned int chunk_sectors = mddev->chunk_sectors;
+ unsigned int bio_sectors = bvm->bi_size >> 9;
+
+ /*
+ * always allow writes to be mergeable, read as well if array
+ * is degraded as we'll go through stripe cache anyway.
+ */
+ if ((bvm->bi_rw & 1) == WRITE || mddev->degraded)
+ return biovec->bv_len;
+
+ if (mddev->new_chunk_sectors < mddev->chunk_sectors)
+ chunk_sectors = mddev->new_chunk_sectors;
+ 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(struct mddev *mddev, struct bio *bio)
+{
+ sector_t sector = bio->bi_iter.bi_sector + get_start_sect(bio->bi_bdev);
+ unsigned int chunk_sectors = mddev->chunk_sectors;
+ unsigned int bio_sectors = bio_sectors(bio);
+
+ if (mddev->new_chunk_sectors < mddev->chunk_sectors)
+ chunk_sectors = mddev->new_chunk_sectors;
+ 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,struct r5conf *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(struct r5conf *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)
+ */
+ raid5_set_bi_stripes(bi, 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;
+ struct mddev *mddev;
+ struct r5conf *conf;
+ int uptodate = test_bit(BIO_UPTODATE, &bi->bi_flags);
+ struct md_rdev *rdev;
+
+ bio_put(bi);
+
+ rdev = (void*)raid_bi->bi_next;
+ raid_bi->bi_next = NULL;
+ mddev = rdev->mddev;
+ conf = mddev->private;
+
+ rdev_dec_pending(rdev, conf->mddev);
+
+ if (!error && uptodate) {
+ trace_block_bio_complete(bdev_get_queue(raid_bi->bi_bdev),
+ raid_bi, 0);
+ 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 (bio_sectors(bi) > queue_max_sectors(q))
+ return 0;
+ blk_recount_segments(q, bi);
+ if (bi->bi_phys_segments > queue_max_segments(q))
+ 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 mddev *mddev, struct bio * raid_bio)
+{
+ struct r5conf *conf = mddev->private;
+ int dd_idx;
+ struct bio* align_bi;
+ struct md_rdev *rdev;
+ sector_t end_sector;
+
+ if (!in_chunk_boundary(mddev, raid_bio)) {
+ pr_debug("chunk_aligned_read : non aligned\n");
+ return 0;
+ }
+ /*
+ * use bio_clone_mddev to make a copy of the bio
+ */
+ align_bi = bio_clone_mddev(raid_bio, GFP_NOIO, mddev);
+ 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_iter.bi_sector =
+ raid5_compute_sector(conf, raid_bio->bi_iter.bi_sector,
+ 0, &dd_idx, NULL);
+
+ end_sector = bio_end_sector(align_bi);
+ rcu_read_lock();
+ rdev = rcu_dereference(conf->disks[dd_idx].replacement);
+ if (!rdev || test_bit(Faulty, &rdev->flags) ||
+ rdev->recovery_offset < end_sector) {
+ rdev = rcu_dereference(conf->disks[dd_idx].rdev);
+ if (rdev &&
+ (test_bit(Faulty, &rdev->flags) ||
+ !(test_bit(In_sync, &rdev->flags) ||
+ rdev->recovery_offset >= end_sector)))
+ rdev = NULL;
+ }
+ if (rdev) {
+ sector_t first_bad;
+ int bad_sectors;
+
+ atomic_inc(&rdev->nr_pending);
+ rcu_read_unlock();
+ raid_bio->bi_next = (void*)rdev;
+ align_bi->bi_bdev = rdev->bdev;
+ __clear_bit(BIO_SEG_VALID, &align_bi->bi_flags);
+
+ if (!bio_fits_rdev(align_bi) ||
+ is_badblock(rdev, align_bi->bi_iter.bi_sector,
+ bio_sectors(align_bi),
+ &first_bad, &bad_sectors)) {
+ /* too big in some way, or has a known bad block */
+ bio_put(align_bi);
+ rdev_dec_pending(rdev, mddev);
+ return 0;
+ }
+
+ /* No reshape active, so we can trust rdev->data_offset */
+ align_bi->bi_iter.bi_sector += rdev->data_offset;
+
+ spin_lock_irq(&conf->device_lock);
+ wait_event_lock_irq(conf->wait_for_stripe,
+ conf->quiesce == 0,
+ conf->device_lock);
+ atomic_inc(&conf->active_aligned_reads);
+ spin_unlock_irq(&conf->device_lock);
+
+ if (mddev->gendisk)
+ trace_block_bio_remap(bdev_get_queue(align_bi->bi_bdev),
+ align_bi, disk_devt(mddev->gendisk),
+ raid_bio->bi_iter.bi_sector);
+ 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(struct r5conf *conf, int group)
+{
+ struct stripe_head *sh = NULL, *tmp;
+ struct list_head *handle_list = NULL;
+ struct r5worker_group *wg = NULL;
+
+ if (conf->worker_cnt_per_group == 0) {
+ handle_list = &conf->handle_list;
+ } else if (group != ANY_GROUP) {
+ handle_list = &conf->worker_groups[group].handle_list;
+ wg = &conf->worker_groups[group];
+ } else {
+ int i;
+ for (i = 0; i < conf->group_cnt; i++) {
+ handle_list = &conf->worker_groups[i].handle_list;
+ wg = &conf->worker_groups[i];
+ if (!list_empty(handle_list))
+ break;
+ }
+ }
+
+ pr_debug("%s: handle: %s hold: %s full_writes: %d bypass_count: %d\n",
+ __func__,
+ list_empty(handle_list) ? "empty" : "busy",
+ list_empty(&conf->hold_list) ? "empty" : "busy",
+ atomic_read(&conf->pending_full_writes), conf->bypass_count);
+
+ if (!list_empty(handle_list)) {
+ sh = list_entry(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)) {
+
+ list_for_each_entry(tmp, &conf->hold_list, lru) {
+ if (conf->worker_cnt_per_group == 0 ||
+ group == ANY_GROUP ||
+ !cpu_online(tmp->cpu) ||
+ cpu_to_group(tmp->cpu) == group) {
+ sh = tmp;
+ break;
+ }
+ }
+
+ if (sh) {
+ conf->bypass_count -= conf->bypass_threshold;
+ if (conf->bypass_count < 0)
+ conf->bypass_count = 0;
+ }
+ wg = NULL;
+ }
+
+ if (!sh)
+ return NULL;
+
+ if (wg) {
+ wg->stripes_cnt--;
+ sh->group = NULL;
+ }
+ list_del_init(&sh->lru);
+ BUG_ON(atomic_inc_return(&sh->count) != 1);
+ return sh;
+}
+
+struct raid5_plug_cb {
+ struct blk_plug_cb cb;
+ struct list_head list;
+ struct list_head temp_inactive_list[NR_STRIPE_HASH_LOCKS];
+};
+
+static void raid5_unplug(struct blk_plug_cb *blk_cb, bool from_schedule)
+{
+ struct raid5_plug_cb *cb = container_of(
+ blk_cb, struct raid5_plug_cb, cb);
+ struct stripe_head *sh;
+ struct mddev *mddev = cb->cb.data;
+ struct r5conf *conf = mddev->private;
+ int cnt = 0;
+ int hash;
+
+ if (cb->list.next && !list_empty(&cb->list)) {
+ spin_lock_irq(&conf->device_lock);
+ while (!list_empty(&cb->list)) {
+ sh = list_first_entry(&cb->list, struct stripe_head, lru);
+ list_del_init(&sh->lru);
+ /*
+ * avoid race release_stripe_plug() sees
+ * STRIPE_ON_UNPLUG_LIST clear but the stripe
+ * is still in our list
+ */
+ smp_mb__before_atomic();
+ clear_bit(STRIPE_ON_UNPLUG_LIST, &sh->state);
+ /*
+ * STRIPE_ON_RELEASE_LIST could be set here. In that
+ * case, the count is always > 1 here
+ */
+ hash = sh->hash_lock_index;
+ __release_stripe(conf, sh, &cb->temp_inactive_list[hash]);
+ cnt++;
+ }
+ spin_unlock_irq(&conf->device_lock);
+ }
+ release_inactive_stripe_list(conf, cb->temp_inactive_list,
+ NR_STRIPE_HASH_LOCKS);
+ if (mddev->queue)
+ trace_block_unplug(mddev->queue, cnt, !from_schedule);
+ kfree(cb);
+}
+
+static void release_stripe_plug(struct mddev *mddev,
+ struct stripe_head *sh)
+{
+ struct blk_plug_cb *blk_cb = blk_check_plugged(
+ raid5_unplug, mddev,
+ sizeof(struct raid5_plug_cb));
+ struct raid5_plug_cb *cb;
+
+ if (!blk_cb) {
+ release_stripe(sh);
+ return;
+ }
+
+ cb = container_of(blk_cb, struct raid5_plug_cb, cb);
+
+ if (cb->list.next == NULL) {
+ int i;
+ INIT_LIST_HEAD(&cb->list);
+ for (i = 0; i < NR_STRIPE_HASH_LOCKS; i++)
+ INIT_LIST_HEAD(cb->temp_inactive_list + i);
+ }
+
+ if (!test_and_set_bit(STRIPE_ON_UNPLUG_LIST, &sh->state))
+ list_add_tail(&sh->lru, &cb->list);
+ else
+ release_stripe(sh);
+}
+
+static void make_discard_request(struct mddev *mddev, struct bio *bi)
+{
+ struct r5conf *conf = mddev->private;
+ sector_t logical_sector, last_sector;
+ struct stripe_head *sh;
+ int remaining;
+ int stripe_sectors;
+
+ if (mddev->reshape_position != MaxSector)
+ /* Skip discard while reshape is happening */
+ return;
+
+ logical_sector = bi->bi_iter.bi_sector & ~((sector_t)STRIPE_SECTORS-1);
+ last_sector = bi->bi_iter.bi_sector + (bi->bi_iter.bi_size>>9);
+
+ bi->bi_next = NULL;
+ bi->bi_phys_segments = 1; /* over-loaded to count active stripes */
+
+ stripe_sectors = conf->chunk_sectors *
+ (conf->raid_disks - conf->max_degraded);
+ logical_sector = DIV_ROUND_UP_SECTOR_T(logical_sector,
+ stripe_sectors);
+ sector_div(last_sector, stripe_sectors);
+
+ logical_sector *= conf->chunk_sectors;
+ last_sector *= conf->chunk_sectors;
+
+ for (; logical_sector < last_sector;
+ logical_sector += STRIPE_SECTORS) {
+ DEFINE_WAIT(w);
+ int d;
+ again:
+ sh = get_active_stripe(conf, logical_sector, 0, 0, 0);
+ prepare_to_wait(&conf->wait_for_overlap, &w,
+ TASK_UNINTERRUPTIBLE);
+ set_bit(R5_Overlap, &sh->dev[sh->pd_idx].flags);
+ if (test_bit(STRIPE_SYNCING, &sh->state)) {
+ release_stripe(sh);
+ schedule();
+ goto again;
+ }
+ clear_bit(R5_Overlap, &sh->dev[sh->pd_idx].flags);
+ spin_lock_irq(&sh->stripe_lock);
+ for (d = 0; d < conf->raid_disks; d++) {
+ if (d == sh->pd_idx || d == sh->qd_idx)
+ continue;
+ if (sh->dev[d].towrite || sh->dev[d].toread) {
+ set_bit(R5_Overlap, &sh->dev[d].flags);
+ spin_unlock_irq(&sh->stripe_lock);
+ release_stripe(sh);
+ schedule();
+ goto again;
+ }
+ }
+ set_bit(STRIPE_DISCARD, &sh->state);
+ finish_wait(&conf->wait_for_overlap, &w);
+ sh->overwrite_disks = 0;
+ for (d = 0; d < conf->raid_disks; d++) {
+ if (d == sh->pd_idx || d == sh->qd_idx)
+ continue;
+ sh->dev[d].towrite = bi;
+ set_bit(R5_OVERWRITE, &sh->dev[d].flags);
+ raid5_inc_bi_active_stripes(bi);
+ sh->overwrite_disks++;
+ }
+ spin_unlock_irq(&sh->stripe_lock);
+ if (conf->mddev->bitmap) {
+ for (d = 0;
+ d < conf->raid_disks - conf->max_degraded;
+ d++)
+ bitmap_startwrite(mddev->bitmap,
+ sh->sector,
+ STRIPE_SECTORS,
+ 0);
+ sh->bm_seq = conf->seq_flush + 1;
+ set_bit(STRIPE_BIT_DELAY, &sh->state);
+ }
+
+ set_bit(STRIPE_HANDLE, &sh->state);
+ clear_bit(STRIPE_DELAYED, &sh->state);
+ if (!test_and_set_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
+ atomic_inc(&conf->preread_active_stripes);
+ release_stripe_plug(mddev, sh);
+ }
+
+ remaining = raid5_dec_bi_active_stripes(bi);
+ if (remaining == 0) {
+ md_write_end(mddev);
+ bio_endio(bi, 0);
+ }
+}
+
+static void make_request(struct mddev *mddev, struct bio * bi)
+{
+ struct r5conf *conf = mddev->private;
+ int dd_idx;
+ sector_t new_sector;
+ sector_t logical_sector, last_sector;
+ struct stripe_head *sh;
+ const int rw = bio_data_dir(bi);
+ int remaining;
+ DEFINE_WAIT(w);
+ bool do_prepare;
+
+ if (unlikely(bi->bi_rw & REQ_FLUSH)) {
+ md_flush_request(mddev, bi);
+ return;
+ }
+
+ md_write_start(mddev, bi);
+
+ /*
+ * If array is degraded, better not do chunk aligned read because
+ * later we might have to read it again in order to reconstruct
+ * data on failed drives.
+ */
+ if (rw == READ && mddev->degraded == 0 &&
+ mddev->reshape_position == MaxSector &&
+ chunk_aligned_read(mddev,bi))
+ return;
+
+ if (unlikely(bi->bi_rw & REQ_DISCARD)) {
+ make_discard_request(mddev, bi);
+ return;
+ }
+
+ logical_sector = bi->bi_iter.bi_sector & ~((sector_t)STRIPE_SECTORS-1);
+ last_sector = bio_end_sector(bi);
+ bi->bi_next = NULL;
+ bi->bi_phys_segments = 1; /* over-loaded to count active stripes */
+
+ prepare_to_wait(&conf->wait_for_overlap, &w, TASK_UNINTERRUPTIBLE);
+ for (;logical_sector < last_sector; logical_sector += STRIPE_SECTORS) {
+ int previous;
+ int seq;
+
+ do_prepare = false;
+ retry:
+ seq = read_seqcount_begin(&conf->gen_lock);
+ previous = 0;
+ if (do_prepare)
+ prepare_to_wait(&conf->wait_for_overlap, &w,
+ TASK_UNINTERRUPTIBLE);
+ if (unlikely(conf->reshape_progress != MaxSector)) {
+ /* spinlock is needed as reshape_progress may be
+ * 64bit on a 32bit platform, and so it might be
+ * possible to see a half-updated value
+ * Of course reshape_progress could change after
+ * the lock is dropped, so once we get a reference
+ * to the stripe that we think it is, we will have
+ * to check again.
+ */
+ spin_lock_irq(&conf->device_lock);
+ if (mddev->reshape_backwards
+ ? logical_sector < conf->reshape_progress
+ : logical_sector >= conf->reshape_progress) {
+ previous = 1;
+ } else {
+ if (mddev->reshape_backwards
+ ? logical_sector < conf->reshape_safe
+ : logical_sector >= conf->reshape_safe) {
+ spin_unlock_irq(&conf->device_lock);
+ schedule();
+ do_prepare = true;
+ goto retry;
+ }
+ }
+ spin_unlock_irq(&conf->device_lock);
+ }
+
+ new_sector = raid5_compute_sector(conf, logical_sector,
+ previous,
+ &dd_idx, NULL);
+ pr_debug("raid456: make_request, sector %llu logical %llu\n",
+ (unsigned long long)new_sector,
+ (unsigned long long)logical_sector);
+
+ sh = get_active_stripe(conf, new_sector, previous,
+ (bi->bi_rw&RWA_MASK), 0);
+ if (sh) {
+ if (unlikely(previous)) {
+ /* expansion might have moved on while waiting for a
+ * stripe, so we must do the range check again.
+ * Expansion could still move past after this
+ * test, but as we are holding a reference to
+ * 'sh', we know that if that happens,
+ * STRIPE_EXPANDING will get set and the expansion
+ * won't proceed until we finish with the stripe.
+ */
+ int must_retry = 0;
+ spin_lock_irq(&conf->device_lock);
+ if (mddev->reshape_backwards
+ ? logical_sector >= conf->reshape_progress
+ : logical_sector < conf->reshape_progress)
+ /* mismatch, need to try again */
+ must_retry = 1;
+ spin_unlock_irq(&conf->device_lock);
+ if (must_retry) {
+ release_stripe(sh);
+ schedule();
+ do_prepare = true;
+ goto retry;
+ }
+ }
+ if (read_seqcount_retry(&conf->gen_lock, seq)) {
+ /* Might have got the wrong stripe_head
+ * by accident
+ */
+ release_stripe(sh);
+ goto retry;
+ }
+
+ if (rw == WRITE &&
+ logical_sector >= mddev->suspend_lo &&
+ logical_sector < mddev->suspend_hi) {
+ release_stripe(sh);
+ /* As the suspend_* range is controlled by
+ * userspace, we want an interruptible
+ * wait.
+ */
+ flush_signals(current);
+ prepare_to_wait(&conf->wait_for_overlap,
+ &w, TASK_INTERRUPTIBLE);
+ if (logical_sector >= mddev->suspend_lo &&
+ logical_sector < mddev->suspend_hi) {
+ schedule();
+ do_prepare = true;
+ }
+ goto retry;
+ }
+
+ if (test_bit(STRIPE_EXPANDING, &sh->state) ||
+ !add_stripe_bio(sh, bi, dd_idx, rw, previous)) {
+ /* Stripe is busy expanding or
+ * add failed due to overlap. Flush everything
+ * and wait a while
+ */
+ md_wakeup_thread(mddev->thread);
+ release_stripe(sh);
+ schedule();
+ do_prepare = true;
+ goto retry;
+ }
+ set_bit(STRIPE_HANDLE, &sh->state);
+ clear_bit(STRIPE_DELAYED, &sh->state);
+ if ((!sh->batch_head || sh == sh->batch_head) &&
+ (bi->bi_rw & REQ_SYNC) &&
+ !test_and_set_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
+ atomic_inc(&conf->preread_active_stripes);
+ release_stripe_plug(mddev, sh);
+ } else {
+ /* cannot get stripe for read-ahead, just give-up */
+ clear_bit(BIO_UPTODATE, &bi->bi_flags);
+ break;
+ }
+ }
+ finish_wait(&conf->wait_for_overlap, &w);
+
+ remaining = raid5_dec_bi_active_stripes(bi);
+ if (remaining == 0) {
+
+ if ( rw == WRITE )
+ md_write_end(mddev);
+
+ trace_block_bio_complete(bdev_get_queue(bi->bi_bdev),
+ bi, 0);
+ bio_endio(bi, 0);
+ }
+}
+
+static sector_t raid5_size(struct mddev *mddev, sector_t sectors, int raid_disks);
+
+static sector_t reshape_request(struct mddev *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.
+ */
+ struct r5conf *conf = mddev->private;
+ struct stripe_head *sh;
+ sector_t first_sector, last_sector;
+ int raid_disks = conf->previous_raid_disks;
+ int data_disks = raid_disks - conf->max_degraded;
+ int new_data_disks = conf->raid_disks - conf->max_degraded;
+ int i;
+ int dd_idx;
+ sector_t writepos, readpos, safepos;
+ sector_t stripe_addr;
+ int reshape_sectors;
+ struct list_head stripes;
+
+ if (sector_nr == 0) {
+ /* If restarting in the middle, skip the initial sectors */
+ if (mddev->reshape_backwards &&
+ conf->reshape_progress < raid5_size(mddev, 0, 0)) {
+ sector_nr = raid5_size(mddev, 0, 0)
+ - conf->reshape_progress;
+ } else if (!mddev->reshape_backwards &&
+ conf->reshape_progress > 0)
+ sector_nr = conf->reshape_progress;
+ sector_div(sector_nr, new_data_disks);
+ if (sector_nr) {
+ mddev->curr_resync_completed = sector_nr;
+ sysfs_notify(&mddev->kobj, NULL, "sync_completed");
+ *skipped = 1;
+ return sector_nr;
+ }
+ }
+
+ /* We need to process a full chunk at a time.
+ * If old and new chunk sizes differ, we need to process the
+ * largest of these
+ */
+ if (mddev->new_chunk_sectors > mddev->chunk_sectors)
+ reshape_sectors = mddev->new_chunk_sectors;
+ else
+ reshape_sectors = mddev->chunk_sectors;
+
+ /* We update the metadata at least every 10 seconds, or when
+ * the data about to be copied would over-write the source of
+ * the data at the front of the range. i.e. one new_stripe
+ * along from reshape_progress new_maps to after where
+ * reshape_safe old_maps to
+ */
+ writepos = conf->reshape_progress;
+ sector_div(writepos, new_data_disks);
+ readpos = conf->reshape_progress;
+ sector_div(readpos, data_disks);
+ safepos = conf->reshape_safe;
+ sector_div(safepos, data_disks);
+ if (mddev->reshape_backwards) {
+ writepos -= min_t(sector_t, reshape_sectors, writepos);
+ readpos += reshape_sectors;
+ safepos += reshape_sectors;
+ } else {
+ writepos += reshape_sectors;
+ readpos -= min_t(sector_t, reshape_sectors, readpos);
+ safepos -= min_t(sector_t, reshape_sectors, safepos);
+ }
+
+ /* Having calculated the 'writepos' possibly use it
+ * to set 'stripe_addr' which is where we will write to.
+ */
+ if (mddev->reshape_backwards) {
+ BUG_ON(conf->reshape_progress == 0);
+ stripe_addr = writepos;
+ BUG_ON((mddev->dev_sectors &
+ ~((sector_t)reshape_sectors - 1))
+ - reshape_sectors - stripe_addr
+ != sector_nr);
+ } else {
+ BUG_ON(writepos != sector_nr + reshape_sectors);
+ stripe_addr = sector_nr;
+ }
+
+ /* 'writepos' is the most advanced device address we might write.
+ * 'readpos' is the least advanced device address we might read.
+ * 'safepos' is the least address recorded in the metadata as having
+ * been reshaped.
+ * If there is a min_offset_diff, these are adjusted either by
+ * increasing the safepos/readpos if diff is negative, or
+ * increasing writepos if diff is positive.
+ * If 'readpos' is then behind 'writepos', there is no way that we can
+ * ensure safety in the face of a crash - that must be done by userspace
+ * making a backup of the data. So in that case there is no particular
+ * rush to update metadata.
+ * Otherwise if 'safepos' is behind 'writepos', then we really need to
+ * update the metadata to advance 'safepos' to match 'readpos' so that
+ * we can be safe in the event of a crash.
+ * So we insist on updating metadata if safepos is behind writepos and
+ * readpos is beyond writepos.
+ * In any case, update the metadata every 10 seconds.
+ * Maybe that number should be configurable, but I'm not sure it is
+ * worth it.... maybe it could be a multiple of safemode_delay???
+ */
+ if (conf->min_offset_diff < 0) {
+ safepos += -conf->min_offset_diff;
+ readpos += -conf->min_offset_diff;
+ } else
+ writepos += conf->min_offset_diff;
+
+ if ((mddev->reshape_backwards
+ ? (safepos > writepos && readpos < writepos)
+ : (safepos < writepos && readpos > writepos)) ||
+ time_after(jiffies, conf->reshape_checkpoint + 10*HZ)) {
+ /* Cannot proceed until we've updated the superblock... */
+ wait_event(conf->wait_for_overlap,
+ atomic_read(&conf->reshape_stripes)==0
+ || test_bit(MD_RECOVERY_INTR, &mddev->recovery));
+ if (atomic_read(&conf->reshape_stripes) != 0)
+ return 0;
+ mddev->reshape_position = conf->reshape_progress;
+ mddev->curr_resync_completed = sector_nr;
+ conf->reshape_checkpoint = jiffies;
+ set_bit(MD_CHANGE_DEVS, &mddev->flags);
+ md_wakeup_thread(mddev->thread);
+ wait_event(mddev->sb_wait, mddev->flags == 0 ||
+ test_bit(MD_RECOVERY_INTR, &mddev->recovery));
+ if (test_bit(MD_RECOVERY_INTR, &mddev->recovery))
+ return 0;
+ spin_lock_irq(&conf->device_lock);
+ conf->reshape_safe = mddev->reshape_position;
+ spin_unlock_irq(&conf->device_lock);
+ wake_up(&conf->wait_for_overlap);
+ sysfs_notify(&mddev->kobj, NULL, "sync_completed");
+ }
+
+ INIT_LIST_HEAD(&stripes);
+ for (i = 0; i < reshape_sectors; i += STRIPE_SECTORS) {
+ int j;
+ int skipped_disk = 0;
+ sh = get_active_stripe(conf, stripe_addr+i, 0, 0, 1);
+ set_bit(STRIPE_EXPANDING, &sh->state);
+ atomic_inc(&conf->reshape_stripes);
+ /* If any of this stripe is beyond the end of the old
+ * array, then we need to zero those blocks
+ */
+ for (j=sh->disks; j--;) {
+ sector_t s;
+ if (j == sh->pd_idx)
+ continue;
+ if (conf->level == 6 &&
+ j == sh->qd_idx)
+ continue;
+ s = compute_blocknr(sh, j, 0);
+ if (s < raid5_size(mddev, 0, 0)) {
+ skipped_disk = 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_disk) {
+ set_bit(STRIPE_EXPAND_READY, &sh->state);
+ set_bit(STRIPE_HANDLE, &sh->state);
+ }
+ list_add(&sh->lru, &stripes);
+ }
+ spin_lock_irq(&conf->device_lock);
+ if (mddev->reshape_backwards)
+ conf->reshape_progress -= reshape_sectors * new_data_disks;
+ else
+ conf->reshape_progress += reshape_sectors * new_data_disks;
+ spin_unlock_irq(&conf->device_lock);
+ /* Ok, those stripe are ready. We can start scheduling
+ * reads on the source stripes.
+ * The source stripes are determined by mapping the first and last
+ * block on the destination stripes.
+ */
+ first_sector =
+ raid5_compute_sector(conf, stripe_addr*(new_data_disks),
+ 1, &dd_idx, NULL);
+ last_sector =
+ raid5_compute_sector(conf, ((stripe_addr+reshape_sectors)
+ * new_data_disks - 1),
+ 1, &dd_idx, NULL);
+ if (last_sector >= mddev->dev_sectors)
+ last_sector = mddev->dev_sectors - 1;
+ while (first_sector <= last_sector) {
+ sh = get_active_stripe(conf, first_sector, 1, 0, 1);
+ set_bit(STRIPE_EXPAND_SOURCE, &sh->state);
+ set_bit(STRIPE_HANDLE, &sh->state);
+ release_stripe(sh);
+ first_sector += STRIPE_SECTORS;
+ }
+ /* Now that the sources are clearly marked, we can release
+ * the destination stripes
+ */
+ while (!list_empty(&stripes)) {
+ sh = list_entry(stripes.next, struct stripe_head, lru);
+ list_del_init(&sh->lru);
+ release_stripe(sh);
+ }
+ /* If this takes us to the resync_max point where we have to pause,
+ * then we need to write out the superblock.
+ */
+ sector_nr += reshape_sectors;
+ if ((sector_nr - mddev->curr_resync_completed) * 2
+ >= mddev->resync_max - mddev->curr_resync_completed) {
+ /* Cannot proceed until we've updated the superblock... */
+ wait_event(conf->wait_for_overlap,
+ atomic_read(&conf->reshape_stripes) == 0
+ || test_bit(MD_RECOVERY_INTR, &mddev->recovery));
+ if (atomic_read(&conf->reshape_stripes) != 0)
+ goto ret;
+ mddev->reshape_position = conf->reshape_progress;
+ mddev->curr_resync_completed = sector_nr;
+ conf->reshape_checkpoint = jiffies;
+ set_bit(MD_CHANGE_DEVS, &mddev->flags);
+ md_wakeup_thread(mddev->thread);
+ wait_event(mddev->sb_wait,
+ !test_bit(MD_CHANGE_DEVS, &mddev->flags)
+ || test_bit(MD_RECOVERY_INTR, &mddev->recovery));
+ if (test_bit(MD_RECOVERY_INTR, &mddev->recovery))
+ goto ret;
+ spin_lock_irq(&conf->device_lock);
+ conf->reshape_safe = mddev->reshape_position;
+ spin_unlock_irq(&conf->device_lock);
+ wake_up(&conf->wait_for_overlap);
+ sysfs_notify(&mddev->kobj, NULL, "sync_completed");
+ }
+ret:
+ return reshape_sectors;
+}
+
+static inline sector_t sync_request(struct mddev *mddev, sector_t sector_nr, int *skipped)
+{
+ struct r5conf *conf = mddev->private;
+ struct stripe_head *sh;
+ sector_t max_sector = mddev->dev_sectors;
+ sector_t sync_blocks;
+ int still_degraded = 0;
+ int i;
+
+ if (sector_nr >= max_sector) {
+ /* just being told to finish up .. nothing much to do */
+
+ 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;
+ }
+
+ /* Allow raid5_quiesce to complete */
+ wait_event(conf->wait_for_overlap, conf->quiesce != 2);
+
+ if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery))
+ return reshape_request(mddev, sector_nr, skipped);
+
+ /* No need to check resync_max as we never do more than one
+ * stripe, and as resync_max will always be on a chunk boundary,
+ * if the check in md_do_sync didn't fire, there is no chance
+ * of overstepping resync_max here
+ */
+
+ /* if there is too many failed drives and we are trying
+ * to resync, then assert that we are finished, because there is
+ * nothing we can do.
+ */
+ if (mddev->degraded >= conf->max_degraded &&
+ test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) {
+ sector_t rv = mddev->dev_sectors - sector_nr;
+ *skipped = 1;
+ return rv;
+ }
+ if (!test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery) &&
+ !conf->fullsync &&
+ !bitmap_start_sync(mddev->bitmap, sector_nr, &sync_blocks, 1) &&
+ sync_blocks >= STRIPE_SECTORS) {
+ /* we can skip this block, and probably more */
+ sync_blocks /= STRIPE_SECTORS;
+ *skipped = 1;
+ return sync_blocks * STRIPE_SECTORS; /* keep things rounded to whole stripes */
+ }
+
+ bitmap_cond_end_sync(mddev->bitmap, sector_nr);
+
+ sh = get_active_stripe(conf, sector_nr, 0, 1, 0);
+ if (sh == NULL) {
+ sh = get_active_stripe(conf, sector_nr, 0, 0, 0);
+ /* make sure we don't swamp the stripe cache if someone else
+ * is trying to get access
+ */
+ schedule_timeout_uninterruptible(1);
+ }
+ /* Need to check if array will still be degraded after recovery/resync
+ * Note in case of > 1 drive failures it's possible we're rebuilding
+ * one drive while leaving another faulty drive in array.
+ */
+ rcu_read_lock();
+ for (i = 0; i < conf->raid_disks; i++) {
+ struct md_rdev *rdev = ACCESS_ONCE(conf->disks[i].rdev);
+
+ if (rdev == NULL || test_bit(Faulty, &rdev->flags))
+ still_degraded = 1;
+ }
+ rcu_read_unlock();
+
+ bitmap_start_sync(mddev->bitmap, sector_nr, &sync_blocks, still_degraded);
+
+ set_bit(STRIPE_SYNC_REQUESTED, &sh->state);
+ set_bit(STRIPE_HANDLE, &sh->state);
+
+ release_stripe(sh);
+
+ return STRIPE_SECTORS;
+}
+
+static int retry_aligned_read(struct r5conf *conf, struct bio *raid_bio)
+{
+ /* We may not be able to submit a whole bio at once as there
+ * may not be enough stripe_heads available.
+ * We cannot pre-allocate enough stripe_heads as we may need
+ * more than exist in the cache (if we allow ever large chunks).
+ * So we do one stripe head at a time and record in
+ * ->bi_hw_segments how many have been done.
+ *
+ * We *know* that this entire raid_bio is in one chunk, so
+ * it will be only one 'dd_idx' and only need one call to raid5_compute_sector.
+ */
+ struct stripe_head *sh;
+ int dd_idx;
+ sector_t sector, logical_sector, last_sector;
+ int scnt = 0;
+ int remaining;
+ int handled = 0;
+
+ logical_sector = raid_bio->bi_iter.bi_sector &
+ ~((sector_t)STRIPE_SECTORS-1);
+ sector = raid5_compute_sector(conf, logical_sector,
+ 0, &dd_idx, NULL);
+ last_sector = bio_end_sector(raid_bio);
+
+ for (; logical_sector < last_sector;
+ logical_sector += STRIPE_SECTORS,
+ sector += STRIPE_SECTORS,
+ scnt++) {
+
+ if (scnt < raid5_bi_processed_stripes(raid_bio))
+ /* already done this stripe */
+ continue;
+
+ sh = get_active_stripe(conf, sector, 0, 1, 1);
+
+ if (!sh) {
+ /* failed to get a stripe - must wait */
+ raid5_set_bi_processed_stripes(raid_bio, scnt);
+ conf->retry_read_aligned = raid_bio;
+ return handled;
+ }
+
+ if (!add_stripe_bio(sh, raid_bio, dd_idx, 0, 0)) {
+ release_stripe(sh);
+ raid5_set_bi_processed_stripes(raid_bio, scnt);
+ conf->retry_read_aligned = raid_bio;
+ return handled;
+ }
+
+ set_bit(R5_ReadNoMerge, &sh->dev[dd_idx].flags);
+ handle_stripe(sh);
+ release_stripe(sh);
+ handled++;
+ }
+ remaining = raid5_dec_bi_active_stripes(raid_bio);
+ if (remaining == 0) {
+ trace_block_bio_complete(bdev_get_queue(raid_bio->bi_bdev),
+ raid_bio, 0);
+ bio_endio(raid_bio, 0);
+ }
+ if (atomic_dec_and_test(&conf->active_aligned_reads))
+ wake_up(&conf->wait_for_stripe);
+ return handled;
+}
+
+static int handle_active_stripes(struct r5conf *conf, int group,
+ struct r5worker *worker,
+ struct list_head *temp_inactive_list)
+{
+ struct stripe_head *batch[MAX_STRIPE_BATCH], *sh;
+ int i, batch_size = 0, hash;
+ bool release_inactive = false;
+
+ while (batch_size < MAX_STRIPE_BATCH &&
+ (sh = __get_priority_stripe(conf, group)) != NULL)
+ batch[batch_size++] = sh;
+
+ if (batch_size == 0) {
+ for (i = 0; i < NR_STRIPE_HASH_LOCKS; i++)
+ if (!list_empty(temp_inactive_list + i))
+ break;
+ if (i == NR_STRIPE_HASH_LOCKS)
+ return batch_size;
+ release_inactive = true;
+ }
+ spin_unlock_irq(&conf->device_lock);
+
+ release_inactive_stripe_list(conf, temp_inactive_list,
+ NR_STRIPE_HASH_LOCKS);
+
+ if (release_inactive) {
+ spin_lock_irq(&conf->device_lock);
+ return 0;
+ }
+
+ for (i = 0; i < batch_size; i++)
+ handle_stripe(batch[i]);
+
+ cond_resched();
+
+ spin_lock_irq(&conf->device_lock);
+ for (i = 0; i < batch_size; i++) {
+ hash = batch[i]->hash_lock_index;
+ __release_stripe(conf, batch[i], &temp_inactive_list[hash]);
+ }
+ return batch_size;
+}
+
+static void raid5_do_work(struct work_struct *work)
+{
+ struct r5worker *worker = container_of(work, struct r5worker, work);
+ struct r5worker_group *group = worker->group;
+ struct r5conf *conf = group->conf;
+ int group_id = group - conf->worker_groups;
+ int handled;
+ struct blk_plug plug;
+
+ pr_debug("+++ raid5worker active\n");
+
+ blk_start_plug(&plug);
+ handled = 0;
+ spin_lock_irq(&conf->device_lock);
+ while (1) {
+ int batch_size, released;
+
+ released = release_stripe_list(conf, worker->temp_inactive_list);
+
+ batch_size = handle_active_stripes(conf, group_id, worker,
+ worker->temp_inactive_list);
+ worker->working = false;
+ if (!batch_size && !released)
+ break;
+ handled += batch_size;
+ }
+ pr_debug("%d stripes handled\n", handled);
+
+ spin_unlock_irq(&conf->device_lock);
+ blk_finish_plug(&plug);
+
+ pr_debug("--- raid5worker inactive\n");
+}
+
+/*
+ * 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(struct md_thread *thread)
+{
+ struct mddev *mddev = thread->mddev;
+ struct r5conf *conf = mddev->private;
+ int handled;
+ struct blk_plug plug;
+
+ pr_debug("+++ raid5d active\n");
+
+ md_check_recovery(mddev);
+
+ blk_start_plug(&plug);
+ handled = 0;
+ spin_lock_irq(&conf->device_lock);
+ while (1) {
+ struct bio *bio;
+ int batch_size, released;
+
+ released = release_stripe_list(conf, conf->temp_inactive_list);
+ if (released)
+ clear_bit(R5_DID_ALLOC, &conf->cache_state);
+
+ if (
+ !list_empty(&conf->bitmap_list)) {
+ /* Now is a good time to flush some bitmap updates */
+ conf->seq_flush++;
+ spin_unlock_irq(&conf->device_lock);
+ bitmap_unplug(mddev->bitmap);
+ spin_lock_irq(&conf->device_lock);
+ conf->seq_write = conf->seq_flush;
+ activate_bit_delay(conf, conf->temp_inactive_list);
+ }
+ raid5_activate_delayed(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++;
+ }
+
+ batch_size = handle_active_stripes(conf, ANY_GROUP, NULL,
+ conf->temp_inactive_list);
+ if (!batch_size && !released)
+ break;
+ handled += batch_size;
+
+ if (mddev->flags & ~(1<<MD_CHANGE_PENDING)) {
+ spin_unlock_irq(&conf->device_lock);
+ md_check_recovery(mddev);
+ spin_lock_irq(&conf->device_lock);
+ }
+ }
+ pr_debug("%d stripes handled\n", handled);
+
+ spin_unlock_irq(&conf->device_lock);
+ if (test_and_clear_bit(R5_ALLOC_MORE, &conf->cache_state)) {
+ grow_one_stripe(conf, __GFP_NOWARN);
+ /* Set flag even if allocation failed. This helps
+ * slow down allocation requests when mem is short
+ */
+ set_bit(R5_DID_ALLOC, &conf->cache_state);
+ }
+
+ async_tx_issue_pending_all();
+ blk_finish_plug(&plug);
+
+ pr_debug("--- raid5d inactive\n");
+}
+
+static ssize_t
+raid5_show_stripe_cache_size(struct mddev *mddev, char *page)
+{
+ struct r5conf *conf;
+ int ret = 0;
+ spin_lock(&mddev->lock);
+ conf = mddev->private;
+ if (conf)
+ ret = sprintf(page, "%d\n", conf->min_nr_stripes);
+ spin_unlock(&mddev->lock);
+ return ret;
+}
+
+int
+raid5_set_cache_size(struct mddev *mddev, int size)
+{
+ struct r5conf *conf = mddev->private;
+ int err;
+
+ if (size <= 16 || size > 32768)
+ return -EINVAL;
+
+ conf->min_nr_stripes = size;
+ while (size < conf->max_nr_stripes &&
+ drop_one_stripe(conf))
+ ;
+
+
+ err = md_allow_write(mddev);
+ if (err)
+ return err;
+
+ while (size > conf->max_nr_stripes)
+ if (!grow_one_stripe(conf, GFP_KERNEL))
+ break;
+
+ return 0;
+}
+EXPORT_SYMBOL(raid5_set_cache_size);
+
+static ssize_t
+raid5_store_stripe_cache_size(struct mddev *mddev, const char *page, size_t len)
+{
+ struct r5conf *conf;
+ unsigned long new;
+ int err;
+
+ if (len >= PAGE_SIZE)
+ return -EINVAL;
+ if (kstrtoul(page, 10, &new))
+ return -EINVAL;
+ err = mddev_lock(mddev);
+ if (err)
+ return err;
+ conf = mddev->private;
+ if (!conf)
+ err = -ENODEV;
+ else
+ err = raid5_set_cache_size(mddev, new);
+ mddev_unlock(mddev);
+
+ return err ?: 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_rmw_level(struct mddev *mddev, char *page)
+{
+ struct r5conf *conf = mddev->private;
+ if (conf)
+ return sprintf(page, "%d\n", conf->rmw_level);
+ else
+ return 0;
+}
+
+static ssize_t
+raid5_store_rmw_level(struct mddev *mddev, const char *page, size_t len)
+{
+ struct r5conf *conf = mddev->private;
+ unsigned long new;
+
+ if (!conf)
+ return -ENODEV;
+
+ if (len >= PAGE_SIZE)
+ return -EINVAL;
+
+ if (kstrtoul(page, 10, &new))
+ return -EINVAL;
+
+ if (new != PARITY_DISABLE_RMW && !raid6_call.xor_syndrome)
+ return -EINVAL;
+
+ if (new != PARITY_DISABLE_RMW &&
+ new != PARITY_ENABLE_RMW &&
+ new != PARITY_PREFER_RMW)
+ return -EINVAL;
+
+ conf->rmw_level = new;
+ return len;
+}
+
+static struct md_sysfs_entry
+raid5_rmw_level = __ATTR(rmw_level, S_IRUGO | S_IWUSR,
+ raid5_show_rmw_level,
+ raid5_store_rmw_level);
+
+
+static ssize_t
+raid5_show_preread_threshold(struct mddev *mddev, char *page)
+{
+ struct r5conf *conf;
+ int ret = 0;
+ spin_lock(&mddev->lock);
+ conf = mddev->private;
+ if (conf)
+ ret = sprintf(page, "%d\n", conf->bypass_threshold);
+ spin_unlock(&mddev->lock);
+ return ret;
+}
+
+static ssize_t
+raid5_store_preread_threshold(struct mddev *mddev, const char *page, size_t len)
+{
+ struct r5conf *conf;
+ unsigned long new;
+ int err;
+
+ if (len >= PAGE_SIZE)
+ return -EINVAL;
+ if (kstrtoul(page, 10, &new))
+ return -EINVAL;
+
+ err = mddev_lock(mddev);
+ if (err)
+ return err;
+ conf = mddev->private;
+ if (!conf)
+ err = -ENODEV;
+ else if (new > conf->min_nr_stripes)
+ err = -EINVAL;
+ else
+ conf->bypass_threshold = new;
+ mddev_unlock(mddev);
+ return err ?: 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
+raid5_show_skip_copy(struct mddev *mddev, char *page)
+{
+ struct r5conf *conf;
+ int ret = 0;
+ spin_lock(&mddev->lock);
+ conf = mddev->private;
+ if (conf)
+ ret = sprintf(page, "%d\n", conf->skip_copy);
+ spin_unlock(&mddev->lock);
+ return ret;
+}
+
+static ssize_t
+raid5_store_skip_copy(struct mddev *mddev, const char *page, size_t len)
+{
+ struct r5conf *conf;
+ unsigned long new;
+ int err;
+
+ if (len >= PAGE_SIZE)
+ return -EINVAL;
+ if (kstrtoul(page, 10, &new))
+ return -EINVAL;
+ new = !!new;
+
+ err = mddev_lock(mddev);
+ if (err)
+ return err;
+ conf = mddev->private;
+ if (!conf)
+ err = -ENODEV;
+ else if (new != conf->skip_copy) {
+ mddev_suspend(mddev);
+ conf->skip_copy = new;
+ if (new)
+ mddev->queue->backing_dev_info.capabilities |=
+ BDI_CAP_STABLE_WRITES;
+ else
+ mddev->queue->backing_dev_info.capabilities &=
+ ~BDI_CAP_STABLE_WRITES;
+ mddev_resume(mddev);
+ }
+ mddev_unlock(mddev);
+ return err ?: len;
+}
+
+static struct md_sysfs_entry
+raid5_skip_copy = __ATTR(skip_copy, S_IRUGO | S_IWUSR,
+ raid5_show_skip_copy,
+ raid5_store_skip_copy);
+
+static ssize_t
+stripe_cache_active_show(struct mddev *mddev, char *page)
+{
+ struct r5conf *conf = mddev->private;
+ 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 ssize_t
+raid5_show_group_thread_cnt(struct mddev *mddev, char *page)
+{
+ struct r5conf *conf;
+ int ret = 0;
+ spin_lock(&mddev->lock);
+ conf = mddev->private;
+ if (conf)
+ ret = sprintf(page, "%d\n", conf->worker_cnt_per_group);
+ spin_unlock(&mddev->lock);
+ return ret;
+}
+
+static int alloc_thread_groups(struct r5conf *conf, int cnt,
+ int *group_cnt,
+ int *worker_cnt_per_group,
+ struct r5worker_group **worker_groups);
+static ssize_t
+raid5_store_group_thread_cnt(struct mddev *mddev, const char *page, size_t len)
+{
+ struct r5conf *conf;
+ unsigned long new;
+ int err;
+ struct r5worker_group *new_groups, *old_groups;
+ int group_cnt, worker_cnt_per_group;
+
+ if (len >= PAGE_SIZE)
+ return -EINVAL;
+ if (kstrtoul(page, 10, &new))
+ return -EINVAL;
+
+ err = mddev_lock(mddev);
+ if (err)
+ return err;
+ conf = mddev->private;
+ if (!conf)
+ err = -ENODEV;
+ else if (new != conf->worker_cnt_per_group) {
+ mddev_suspend(mddev);
+
+ old_groups = conf->worker_groups;
+ if (old_groups)
+ flush_workqueue(raid5_wq);
+
+ err = alloc_thread_groups(conf, new,
+ &group_cnt, &worker_cnt_per_group,
+ &new_groups);
+ if (!err) {
+ spin_lock_irq(&conf->device_lock);
+ conf->group_cnt = group_cnt;
+ conf->worker_cnt_per_group = worker_cnt_per_group;
+ conf->worker_groups = new_groups;
+ spin_unlock_irq(&conf->device_lock);
+
+ if (old_groups)
+ kfree(old_groups[0].workers);
+ kfree(old_groups);
+ }
+ mddev_resume(mddev);
+ }
+ mddev_unlock(mddev);
+
+ return err ?: len;
+}
+
+static struct md_sysfs_entry
+raid5_group_thread_cnt = __ATTR(group_thread_cnt, S_IRUGO | S_IWUSR,
+ raid5_show_group_thread_cnt,
+ raid5_store_group_thread_cnt);
+
+static struct attribute *raid5_attrs[] = {
+ &raid5_stripecache_size.attr,
+ &raid5_stripecache_active.attr,
+ &raid5_preread_bypass_threshold.attr,
+ &raid5_group_thread_cnt.attr,
+ &raid5_skip_copy.attr,
+ &raid5_rmw_level.attr,
+ NULL,
+};
+static struct attribute_group raid5_attrs_group = {
+ .name = NULL,
+ .attrs = raid5_attrs,
+};
+
+static int alloc_thread_groups(struct r5conf *conf, int cnt,
+ int *group_cnt,
+ int *worker_cnt_per_group,
+ struct r5worker_group **worker_groups)
+{
+ int i, j, k;
+ ssize_t size;
+ struct r5worker *workers;
+
+ *worker_cnt_per_group = cnt;
+ if (cnt == 0) {
+ *group_cnt = 0;
+ *worker_groups = NULL;
+ return 0;
+ }
+ *group_cnt = num_possible_nodes();
+ size = sizeof(struct r5worker) * cnt;
+ workers = kzalloc(size * *group_cnt, GFP_NOIO);
+ *worker_groups = kzalloc(sizeof(struct r5worker_group) *
+ *group_cnt, GFP_NOIO);
+ if (!*worker_groups || !workers) {
+ kfree(workers);
+ kfree(*worker_groups);
+ return -ENOMEM;
+ }
+
+ for (i = 0; i < *group_cnt; i++) {
+ struct r5worker_group *group;
+
+ group = &(*worker_groups)[i];
+ INIT_LIST_HEAD(&group->handle_list);
+ group->conf = conf;
+ group->workers = workers + i * cnt;
+
+ for (j = 0; j < cnt; j++) {
+ struct r5worker *worker = group->workers + j;
+ worker->group = group;
+ INIT_WORK(&worker->work, raid5_do_work);
+
+ for (k = 0; k < NR_STRIPE_HASH_LOCKS; k++)
+ INIT_LIST_HEAD(worker->temp_inactive_list + k);
+ }
+ }
+
+ return 0;
+}
+
+static void free_thread_groups(struct r5conf *conf)
+{
+ if (conf->worker_groups)
+ kfree(conf->worker_groups[0].workers);
+ kfree(conf->worker_groups);
+ conf->worker_groups = NULL;
+}
+
+static sector_t
+raid5_size(struct mddev *mddev, sector_t sectors, int raid_disks)
+{
+ struct r5conf *conf = mddev->private;
+
+ if (!sectors)
+ sectors = mddev->dev_sectors;
+ if (!raid_disks)
+ /* size is defined by the smallest of previous and new size */
+ raid_disks = min(conf->raid_disks, conf->previous_raid_disks);
+
+ sectors &= ~((sector_t)mddev->chunk_sectors - 1);
+ sectors &= ~((sector_t)mddev->new_chunk_sectors - 1);
+ return sectors * (raid_disks - conf->max_degraded);
+}
+
+static void free_scratch_buffer(struct r5conf *conf, struct raid5_percpu *percpu)
+{
+ safe_put_page(percpu->spare_page);
+ if (percpu->scribble)
+ flex_array_free(percpu->scribble);
+ percpu->spare_page = NULL;
+ percpu->scribble = NULL;
+}
+
+static int alloc_scratch_buffer(struct r5conf *conf, struct raid5_percpu *percpu)
+{
+ if (conf->level == 6 && !percpu->spare_page)
+ percpu->spare_page = alloc_page(GFP_KERNEL);
+ if (!percpu->scribble)
+ percpu->scribble = scribble_alloc(max(conf->raid_disks,
+ conf->previous_raid_disks),
+ max(conf->chunk_sectors,
+ conf->prev_chunk_sectors)
+ / STRIPE_SECTORS,
+ GFP_KERNEL);
+
+ if (!percpu->scribble || (conf->level == 6 && !percpu->spare_page)) {
+ free_scratch_buffer(conf, percpu);
+ return -ENOMEM;
+ }
+
+ return 0;
+}
+
+static void raid5_free_percpu(struct r5conf *conf)
+{
+ unsigned long cpu;
+
+ if (!conf->percpu)
+ return;
+
+#ifdef CONFIG_HOTPLUG_CPU
+ unregister_cpu_notifier(&conf->cpu_notify);
+#endif
+
+ get_online_cpus();
+ for_each_possible_cpu(cpu)
+ free_scratch_buffer(conf, per_cpu_ptr(conf->percpu, cpu));
+ put_online_cpus();
+
+ free_percpu(conf->percpu);
+}
+
+static void free_conf(struct r5conf *conf)
+{
+ if (conf->shrinker.seeks)
+ unregister_shrinker(&conf->shrinker);
+ free_thread_groups(conf);
+ shrink_stripes(conf);
+ raid5_free_percpu(conf);
+ kfree(conf->disks);
+ kfree(conf->stripe_hashtbl);
+ kfree(conf);
+}
+
+#ifdef CONFIG_HOTPLUG_CPU
+static int raid456_cpu_notify(struct notifier_block *nfb, unsigned long action,
+ void *hcpu)
+{
+ struct r5conf *conf = container_of(nfb, struct r5conf, cpu_notify);
+ long cpu = (long)hcpu;
+ struct raid5_percpu *percpu = per_cpu_ptr(conf->percpu, cpu);
+
+ switch (action) {
+ case CPU_UP_PREPARE:
+ case CPU_UP_PREPARE_FROZEN:
+ if (alloc_scratch_buffer(conf, percpu)) {
+ pr_err("%s: failed memory allocation for cpu%ld\n",
+ __func__, cpu);
+ return notifier_from_errno(-ENOMEM);
+ }
+ break;
+ case CPU_DEAD:
+ case CPU_DEAD_FROZEN:
+ free_scratch_buffer(conf, per_cpu_ptr(conf->percpu, cpu));
+ break;
+ default:
+ break;
+ }
+ return NOTIFY_OK;
+}
+#endif
+
+static int raid5_alloc_percpu(struct r5conf *conf)
+{
+ unsigned long cpu;
+ int err = 0;
+
+ conf->percpu = alloc_percpu(struct raid5_percpu);
+ if (!conf->percpu)
+ return -ENOMEM;
+
+#ifdef CONFIG_HOTPLUG_CPU
+ conf->cpu_notify.notifier_call = raid456_cpu_notify;
+ conf->cpu_notify.priority = 0;
+ err = register_cpu_notifier(&conf->cpu_notify);
+ if (err)
+ return err;
+#endif
+
+ get_online_cpus();
+ for_each_present_cpu(cpu) {
+ err = alloc_scratch_buffer(conf, per_cpu_ptr(conf->percpu, cpu));
+ if (err) {
+ pr_err("%s: failed memory allocation for cpu%ld\n",
+ __func__, cpu);
+ break;
+ }
+ spin_lock_init(&per_cpu_ptr(conf->percpu, cpu)->lock);
+ }
+ put_online_cpus();
+
+ return err;
+}
+
+static unsigned long raid5_cache_scan(struct shrinker *shrink,
+ struct shrink_control *sc)
+{
+ struct r5conf *conf = container_of(shrink, struct r5conf, shrinker);
+ int ret = 0;
+ while (ret < sc->nr_to_scan) {
+ if (drop_one_stripe(conf) == 0)
+ return SHRINK_STOP;
+ ret++;
+ }
+ return ret;
+}
+
+static unsigned long raid5_cache_count(struct shrinker *shrink,
+ struct shrink_control *sc)
+{
+ struct r5conf *conf = container_of(shrink, struct r5conf, shrinker);
+
+ if (conf->max_nr_stripes < conf->min_nr_stripes)
+ /* unlikely, but not impossible */
+ return 0;
+ return conf->max_nr_stripes - conf->min_nr_stripes;
+}
+
+static struct r5conf *setup_conf(struct mddev *mddev)
+{
+ struct r5conf *conf;
+ int raid_disk, memory, max_disks;
+ struct md_rdev *rdev;
+ struct disk_info *disk;
+ char pers_name[6];
+ int i;
+ int group_cnt, worker_cnt_per_group;
+ struct r5worker_group *new_group;
+
+ if (mddev->new_level != 5
+ && mddev->new_level != 4
+ && mddev->new_level != 6) {
+ printk(KERN_ERR "md/raid:%s: raid level not set to 4/5/6 (%d)\n",
+ mdname(mddev), mddev->new_level);
+ return ERR_PTR(-EIO);
+ }
+ if ((mddev->new_level == 5
+ && !algorithm_valid_raid5(mddev->new_layout)) ||
+ (mddev->new_level == 6
+ && !algorithm_valid_raid6(mddev->new_layout))) {
+ printk(KERN_ERR "md/raid:%s: layout %d not supported\n",
+ mdname(mddev), mddev->new_layout);
+ return ERR_PTR(-EIO);
+ }
+ if (mddev->new_level == 6 && mddev->raid_disks < 4) {
+ printk(KERN_ERR "md/raid:%s: not enough configured devices (%d, minimum 4)\n",
+ mdname(mddev), mddev->raid_disks);
+ return ERR_PTR(-EINVAL);
+ }
+
+ if (!mddev->new_chunk_sectors ||
+ (mddev->new_chunk_sectors << 9) % PAGE_SIZE ||
+ !is_power_of_2(mddev->new_chunk_sectors)) {
+ printk(KERN_ERR "md/raid:%s: invalid chunk size %d\n",
+ mdname(mddev), mddev->new_chunk_sectors << 9);
+ return ERR_PTR(-EINVAL);
+ }
+
+ conf = kzalloc(sizeof(struct r5conf), GFP_KERNEL);
+ if (conf == NULL)
+ goto abort;
+ /* Don't enable multi-threading by default*/
+ if (!alloc_thread_groups(conf, 0, &group_cnt, &worker_cnt_per_group,
+ &new_group)) {
+ conf->group_cnt = group_cnt;
+ conf->worker_cnt_per_group = worker_cnt_per_group;
+ conf->worker_groups = new_group;
+ } else
+ goto abort;
+ spin_lock_init(&conf->device_lock);
+ seqcount_init(&conf->gen_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_llist_head(&conf->released_stripes);
+ 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;
+ conf->recovery_disabled = mddev->recovery_disabled - 1;
+
+ conf->raid_disks = mddev->raid_disks;
+ if (mddev->reshape_position == MaxSector)
+ conf->previous_raid_disks = mddev->raid_disks;
+ else
+ conf->previous_raid_disks = mddev->raid_disks - mddev->delta_disks;
+ max_disks = max(conf->raid_disks, conf->previous_raid_disks);
+
+ conf->disks = kzalloc(max_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;
+
+ /* We init hash_locks[0] separately to that it can be used
+ * as the reference lock in the spin_lock_nest_lock() call
+ * in lock_all_device_hash_locks_irq in order to convince
+ * lockdep that we know what we are doing.
+ */
+ spin_lock_init(conf->hash_locks);
+ for (i = 1; i < NR_STRIPE_HASH_LOCKS; i++)
+ spin_lock_init(conf->hash_locks + i);
+
+ for (i = 0; i < NR_STRIPE_HASH_LOCKS; i++)
+ INIT_LIST_HEAD(conf->inactive_list + i);
+
+ for (i = 0; i < NR_STRIPE_HASH_LOCKS; i++)
+ INIT_LIST_HEAD(conf->temp_inactive_list + i);
+
+ conf->level = mddev->new_level;
+ conf->chunk_sectors = mddev->new_chunk_sectors;
+ if (raid5_alloc_percpu(conf) != 0)
+ goto abort;
+
+ pr_debug("raid456: run(%s) called.\n", mdname(mddev));
+
+ rdev_for_each(rdev, mddev) {
+ raid_disk = rdev->raid_disk;
+ if (raid_disk >= max_disks
+ || raid_disk < 0)
+ continue;
+ disk = conf->disks + raid_disk;
+
+ if (test_bit(Replacement, &rdev->flags)) {
+ if (disk->replacement)
+ goto abort;
+ disk->replacement = rdev;
+ } else {
+ if (disk->rdev)
+ goto abort;
+ disk->rdev = rdev;
+ }
+
+ if (test_bit(In_sync, &rdev->flags)) {
+ char b[BDEVNAME_SIZE];
+ printk(KERN_INFO "md/raid:%s: device %s operational as raid"
+ " disk %d\n",
+ mdname(mddev), bdevname(rdev->bdev, b), raid_disk);
+ } else if (rdev->saved_raid_disk != raid_disk)
+ /* Cannot rely on bitmap to complete recovery */
+ conf->fullsync = 1;
+ }
+
+ conf->level = mddev->new_level;
+ if (conf->level == 6) {
+ conf->max_degraded = 2;
+ if (raid6_call.xor_syndrome)
+ conf->rmw_level = PARITY_ENABLE_RMW;
+ else
+ conf->rmw_level = PARITY_DISABLE_RMW;
+ } else {
+ conf->max_degraded = 1;
+ conf->rmw_level = PARITY_ENABLE_RMW;
+ }
+ conf->algorithm = mddev->new_layout;
+ conf->reshape_progress = mddev->reshape_position;
+ if (conf->reshape_progress != MaxSector) {
+ conf->prev_chunk_sectors = mddev->chunk_sectors;
+ conf->prev_algo = mddev->layout;
+ }
+
+ conf->min_nr_stripes = NR_STRIPES;
+ memory = conf->min_nr_stripes * (sizeof(struct stripe_head) +
+ max_disks * ((sizeof(struct bio) + PAGE_SIZE))) / 1024;
+ atomic_set(&conf->empty_inactive_list_nr, NR_STRIPE_HASH_LOCKS);
+ if (grow_stripes(conf, conf->min_nr_stripes)) {
+ printk(KERN_ERR
+ "md/raid:%s: couldn't allocate %dkB for buffers\n",
+ mdname(mddev), memory);
+ goto abort;
+ } else
+ printk(KERN_INFO "md/raid:%s: allocated %dkB\n",
+ mdname(mddev), memory);
+ /*
+ * Losing a stripe head costs more than the time to refill it,
+ * it reduces the queue depth and so can hurt throughput.
+ * So set it rather large, scaled by number of devices.
+ */
+ conf->shrinker.seeks = DEFAULT_SEEKS * conf->raid_disks * 4;
+ conf->shrinker.scan_objects = raid5_cache_scan;
+ conf->shrinker.count_objects = raid5_cache_count;
+ conf->shrinker.batch = 128;
+ conf->shrinker.flags = 0;
+ register_shrinker(&conf->shrinker);
+
+ sprintf(pers_name, "raid%d", mddev->new_level);
+ conf->thread = md_register_thread(raid5d, mddev, pers_name);
+ if (!conf->thread) {
+ printk(KERN_ERR
+ "md/raid:%s: couldn't allocate thread.\n",
+ mdname(mddev));
+ goto abort;
+ }
+
+ return conf;
+
+ abort:
+ if (conf) {
+ free_conf(conf);
+ return ERR_PTR(-EIO);
+ } else
+ return ERR_PTR(-ENOMEM);
+}
+
+static int only_parity(int raid_disk, int algo, int raid_disks, int max_degraded)
+{
+ switch (algo) {
+ case ALGORITHM_PARITY_0:
+ if (raid_disk < max_degraded)
+ return 1;
+ break;
+ case ALGORITHM_PARITY_N:
+ if (raid_disk >= raid_disks - max_degraded)
+ return 1;
+ break;
+ case ALGORITHM_PARITY_0_6:
+ if (raid_disk == 0 ||
+ raid_disk == raid_disks - 1)
+ return 1;
+ break;
+ case ALGORITHM_LEFT_ASYMMETRIC_6:
+ case ALGORITHM_RIGHT_ASYMMETRIC_6:
+ case ALGORITHM_LEFT_SYMMETRIC_6:
+ case ALGORITHM_RIGHT_SYMMETRIC_6:
+ if (raid_disk == raid_disks - 1)
+ return 1;
+ }
+ return 0;
+}
+
+static int run(struct mddev *mddev)
+{
+ struct r5conf *conf;
+ int working_disks = 0;
+ int dirty_parity_disks = 0;
+ struct md_rdev *rdev;
+ sector_t reshape_offset = 0;
+ int i;
+ long long min_offset_diff = 0;
+ int first = 1;
+
+ if (mddev->recovery_cp != MaxSector)
+ printk(KERN_NOTICE "md/raid:%s: not clean"
+ " -- starting background reconstruction\n",
+ mdname(mddev));
+
+ rdev_for_each(rdev, mddev) {
+ long long diff;
+ if (rdev->raid_disk < 0)
+ continue;
+ diff = (rdev->new_data_offset - rdev->data_offset);
+ if (first) {
+ min_offset_diff = diff;
+ first = 0;
+ } else if (mddev->reshape_backwards &&
+ diff < min_offset_diff)
+ min_offset_diff = diff;
+ else if (!mddev->reshape_backwards &&
+ diff > min_offset_diff)
+ min_offset_diff = diff;
+ }
+
+ if (mddev->reshape_position != MaxSector) {
+ /* Check that we can continue the reshape.
+ * Difficulties arise if the stripe we would write to
+ * next is at or after the stripe we would read from next.
+ * For a reshape that changes the number of devices, this
+ * is only possible for a very short time, and mdadm makes
+ * sure that time appears to have past before assembling
+ * the array. So we fail if that time hasn't passed.
+ * For a reshape that keeps the number of devices the same
+ * mdadm must be monitoring the reshape can keeping the
+ * critical areas read-only and backed up. It will start
+ * the array in read-only mode, so we check for that.
+ */
+ sector_t here_new, here_old;
+ int old_disks;
+ int max_degraded = (mddev->level == 6 ? 2 : 1);
+
+ if (mddev->new_level != mddev->level) {
+ printk(KERN_ERR "md/raid:%s: unsupported reshape "
+ "required - aborting.\n",
+ mdname(mddev));
+ return -EINVAL;
+ }
+ old_disks = mddev->raid_disks - mddev->delta_disks;
+ /* reshape_position must be on a new-stripe boundary, and one
+ * further up in new geometry must map after here in old
+ * geometry.
+ */
+ here_new = mddev->reshape_position;
+ if (sector_div(here_new, mddev->new_chunk_sectors *
+ (mddev->raid_disks - max_degraded))) {
+ printk(KERN_ERR "md/raid:%s: reshape_position not "
+ "on a stripe boundary\n", mdname(mddev));
+ return -EINVAL;
+ }
+ reshape_offset = here_new * mddev->new_chunk_sectors;
+ /* here_new is the stripe we will write to */
+ here_old = mddev->reshape_position;
+ sector_div(here_old, mddev->chunk_sectors *
+ (old_disks-max_degraded));
+ /* here_old is the first stripe that we might need to read
+ * from */
+ if (mddev->delta_disks == 0) {
+ if ((here_new * mddev->new_chunk_sectors !=
+ here_old * mddev->chunk_sectors)) {
+ printk(KERN_ERR "md/raid:%s: reshape position is"
+ " confused - aborting\n", mdname(mddev));
+ return -EINVAL;
+ }
+ /* We cannot be sure it is safe to start an in-place
+ * reshape. It is only safe if user-space is monitoring
+ * and taking constant backups.
+ * mdadm always starts a situation like this in
+ * readonly mode so it can take control before
+ * allowing any writes. So just check for that.
+ */
+ if (abs(min_offset_diff) >= mddev->chunk_sectors &&
+ abs(min_offset_diff) >= mddev->new_chunk_sectors)
+ /* not really in-place - so OK */;
+ else if (mddev->ro == 0) {
+ printk(KERN_ERR "md/raid:%s: in-place reshape "
+ "must be started in read-only mode "
+ "- aborting\n",
+ mdname(mddev));
+ return -EINVAL;
+ }
+ } else if (mddev->reshape_backwards
+ ? (here_new * mddev->new_chunk_sectors + min_offset_diff <=
+ here_old * mddev->chunk_sectors)
+ : (here_new * mddev->new_chunk_sectors >=
+ here_old * mddev->chunk_sectors + (-min_offset_diff))) {
+ /* Reading from the same stripe as writing to - bad */
+ printk(KERN_ERR "md/raid:%s: reshape_position too early for "
+ "auto-recovery - aborting.\n",
+ mdname(mddev));
+ return -EINVAL;
+ }
+ printk(KERN_INFO "md/raid:%s: reshape will continue\n",
+ mdname(mddev));
+ /* OK, we should be able to continue; */
+ } else {
+ BUG_ON(mddev->level != mddev->new_level);
+ BUG_ON(mddev->layout != mddev->new_layout);
+ BUG_ON(mddev->chunk_sectors != mddev->new_chunk_sectors);
+ BUG_ON(mddev->delta_disks != 0);
+ }
+
+ if (mddev->private == NULL)
+ conf = setup_conf(mddev);
+ else
+ conf = mddev->private;
+
+ if (IS_ERR(conf))
+ return PTR_ERR(conf);
+
+ conf->min_offset_diff = min_offset_diff;
+ mddev->thread = conf->thread;
+ conf->thread = NULL;
+ mddev->private = conf;
+
+ for (i = 0; i < conf->raid_disks && conf->previous_raid_disks;
+ i++) {
+ rdev = conf->disks[i].rdev;
+ if (!rdev && conf->disks[i].replacement) {
+ /* The replacement is all we have yet */
+ rdev = conf->disks[i].replacement;
+ conf->disks[i].replacement = NULL;
+ clear_bit(Replacement, &rdev->flags);
+ conf->disks[i].rdev = rdev;
+ }
+ if (!rdev)
+ continue;
+ if (conf->disks[i].replacement &&
+ conf->reshape_progress != MaxSector) {
+ /* replacements and reshape simply do not mix. */
+ printk(KERN_ERR "md: cannot handle concurrent "
+ "replacement and reshape.\n");
+ goto abort;
+ }
+ if (test_bit(In_sync, &rdev->flags)) {
+ working_disks++;
+ continue;
+ }
+ /* This disc is not fully in-sync. However if it
+ * just stored parity (beyond the recovery_offset),
+ * when we don't need to be concerned about the
+ * array being dirty.
+ * When reshape goes 'backwards', we never have
+ * partially completed devices, so we only need
+ * to worry about reshape going forwards.
+ */
+ /* Hack because v0.91 doesn't store recovery_offset properly. */
+ if (mddev->major_version == 0 &&
+ mddev->minor_version > 90)
+ rdev->recovery_offset = reshape_offset;
+
+ if (rdev->recovery_offset < reshape_offset) {
+ /* We need to check old and new layout */
+ if (!only_parity(rdev->raid_disk,
+ conf->algorithm,
+ conf->raid_disks,
+ conf->max_degraded))
+ continue;
+ }
+ if (!only_parity(rdev->raid_disk,
+ conf->prev_algo,
+ conf->previous_raid_disks,
+ conf->max_degraded))
+ continue;
+ dirty_parity_disks++;
+ }
+
+ /*
+ * 0 for a fully functional array, 1 or 2 for a degraded array.
+ */
+ mddev->degraded = calc_degraded(conf);
+
+ if (has_failed(conf)) {
+ printk(KERN_ERR "md/raid:%s: not enough operational devices"
+ " (%d/%d failed)\n",
+ mdname(mddev), mddev->degraded, conf->raid_disks);
+ goto abort;
+ }
+
+ /* device size must be a multiple of chunk size */
+ mddev->dev_sectors &= ~(mddev->chunk_sectors - 1);
+ mddev->resync_max_sectors = mddev->dev_sectors;
+
+ if (mddev->degraded > dirty_parity_disks &&
+ mddev->recovery_cp != MaxSector) {
+ if (mddev->ok_start_degraded)
+ printk(KERN_WARNING
+ "md/raid:%s: starting dirty degraded array"
+ " - data corruption possible.\n",
+ mdname(mddev));
+ else {
+ printk(KERN_ERR
+ "md/raid:%s: cannot start dirty degraded array.\n",
+ mdname(mddev));
+ goto abort;
+ }
+ }
+
+ if (mddev->degraded == 0)
+ printk(KERN_INFO "md/raid:%s: raid level %d active with %d out of %d"
+ " devices, algorithm %d\n", mdname(mddev), conf->level,
+ mddev->raid_disks-mddev->degraded, mddev->raid_disks,
+ mddev->new_layout);
+ else
+ printk(KERN_ALERT "md/raid:%s: raid level %d active with %d"
+ " out of %d devices, algorithm %d\n",
+ mdname(mddev), conf->level,
+ mddev->raid_disks - mddev->degraded,
+ mddev->raid_disks, mddev->new_layout);
+
+ print_raid5_conf(conf);
+
+ if (conf->reshape_progress != MaxSector) {
+ conf->reshape_safe = conf->reshape_progress;
+ atomic_set(&conf->reshape_stripes, 0);
+ clear_bit(MD_RECOVERY_SYNC, &mddev->recovery);
+ clear_bit(MD_RECOVERY_CHECK, &mddev->recovery);
+ set_bit(MD_RECOVERY_RESHAPE, &mddev->recovery);
+ set_bit(MD_RECOVERY_RUNNING, &mddev->recovery);
+ mddev->sync_thread = md_register_thread(md_do_sync, mddev,
+ "reshape");
+ }
+
+ /* Ok, everything is just fine now */
+ if (mddev->to_remove == &raid5_attrs_group)
+ mddev->to_remove = NULL;
+ else if (mddev->kobj.sd &&
+ sysfs_create_group(&mddev->kobj, &raid5_attrs_group))
+ printk(KERN_WARNING
+ "raid5: failed to create sysfs attributes for %s\n",
+ mdname(mddev));
+ md_set_array_sectors(mddev, raid5_size(mddev, 0, 0));
+
+ if (mddev->queue) {
+ int chunk_size;
+ bool discard_supported = true;
+ /* 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_sectors << 9) / PAGE_SIZE);
+ if (mddev->queue->backing_dev_info.ra_pages < 2 * stripe)
+ mddev->queue->backing_dev_info.ra_pages = 2 * stripe;
+
+ chunk_size = mddev->chunk_sectors << 9;
+ blk_queue_io_min(mddev->queue, chunk_size);
+ blk_queue_io_opt(mddev->queue, chunk_size *
+ (conf->raid_disks - conf->max_degraded));
+ mddev->queue->limits.raid_partial_stripes_expensive = 1;
+ /*
+ * We can only discard a whole stripe. It doesn't make sense to
+ * discard data disk but write parity disk
+ */
+ stripe = stripe * PAGE_SIZE;
+ /* Round up to power of 2, as discard handling
+ * currently assumes that */
+ while ((stripe-1) & stripe)
+ stripe = (stripe | (stripe-1)) + 1;
+ mddev->queue->limits.discard_alignment = stripe;
+ mddev->queue->limits.discard_granularity = stripe;
+ /*
+ * unaligned part of discard request will be ignored, so can't
+ * guarantee discard_zeroes_data
+ */
+ mddev->queue->limits.discard_zeroes_data = 0;
+
+ blk_queue_max_write_same_sectors(mddev->queue, 0);
+
+ rdev_for_each(rdev, mddev) {
+ disk_stack_limits(mddev->gendisk, rdev->bdev,
+ rdev->data_offset << 9);
+ disk_stack_limits(mddev->gendisk, rdev->bdev,
+ rdev->new_data_offset << 9);
+ /*
+ * discard_zeroes_data is required, otherwise data
+ * could be lost. Consider a scenario: discard a stripe
+ * (the stripe could be inconsistent if
+ * discard_zeroes_data is 0); write one disk of the
+ * stripe (the stripe could be inconsistent again
+ * depending on which disks are used to calculate
+ * parity); the disk is broken; The stripe data of this
+ * disk is lost.
+ */
+ if (!blk_queue_discard(bdev_get_queue(rdev->bdev)) ||
+ !bdev_get_queue(rdev->bdev)->
+ limits.discard_zeroes_data)
+ discard_supported = false;
+ /* Unfortunately, discard_zeroes_data is not currently
+ * a guarantee - just a hint. So we only allow DISCARD
+ * if the sysadmin has confirmed that only safe devices
+ * are in use by setting a module parameter.
+ */
+ if (!devices_handle_discard_safely) {
+ if (discard_supported) {
+ pr_info("md/raid456: discard support disabled due to uncertainty.\n");
+ pr_info("Set raid456.devices_handle_discard_safely=Y to override.\n");
+ }
+ discard_supported = false;
+ }
+ }
+
+ if (discard_supported &&
+ mddev->queue->limits.max_discard_sectors >= stripe &&
+ mddev->queue->limits.discard_granularity >= stripe)
+ queue_flag_set_unlocked(QUEUE_FLAG_DISCARD,
+ mddev->queue);
+ else
+ queue_flag_clear_unlocked(QUEUE_FLAG_DISCARD,
+ mddev->queue);
+ }
+
+ return 0;
+abort:
+ md_unregister_thread(&mddev->thread);
+ print_raid5_conf(conf);
+ free_conf(conf);
+ mddev->private = NULL;
+ printk(KERN_ALERT "md/raid:%s: failed to run raid set.\n", mdname(mddev));
+ return -EIO;
+}
+
+static void raid5_free(struct mddev *mddev, void *priv)
+{
+ struct r5conf *conf = priv;
+
+ free_conf(conf);
+ mddev->to_remove = &raid5_attrs_group;
+}
+
+static void status(struct seq_file *seq, struct mddev *mddev)
+{
+ struct r5conf *conf = mddev->private;
+ int i;
+
+ seq_printf(seq, " level %d, %dk chunk, algorithm %d", mddev->level,
+ mddev->chunk_sectors / 2, 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, "]");
+}
+
+static void print_raid5_conf (struct r5conf *conf)
+{
+ int i;
+ struct disk_info *tmp;
+
+ printk(KERN_DEBUG "RAID conf printout:\n");
+ if (!conf) {
+ printk("(conf==NULL)\n");
+ return;
+ }
+ printk(KERN_DEBUG " --- level:%d rd:%d wd:%d\n", conf->level,
+ 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(KERN_DEBUG " disk %d, o:%d, dev:%s\n",
+ i, !test_bit(Faulty, &tmp->rdev->flags),
+ bdevname(tmp->rdev->bdev, b));
+ }
+}
+
+static int raid5_spare_active(struct mddev *mddev)
+{
+ int i;
+ struct r5conf *conf = mddev->private;
+ struct disk_info *tmp;
+ int count = 0;
+ unsigned long flags;
+
+ for (i = 0; i < conf->raid_disks; i++) {
+ tmp = conf->disks + i;
+ if (tmp->replacement
+ && tmp->replacement->recovery_offset == MaxSector
+ && !test_bit(Faulty, &tmp->replacement->flags)
+ && !test_and_set_bit(In_sync, &tmp->replacement->flags)) {
+ /* Replacement has just become active. */
+ if (!tmp->rdev
+ || !test_and_clear_bit(In_sync, &tmp->rdev->flags))
+ count++;
+ if (tmp->rdev) {
+ /* Replaced device not technically faulty,
+ * but we need to be sure it gets removed
+ * and never re-added.
+ */
+ set_bit(Faulty, &tmp->rdev->flags);
+ sysfs_notify_dirent_safe(
+ tmp->rdev->sysfs_state);
+ }
+ sysfs_notify_dirent_safe(tmp->replacement->sysfs_state);
+ } else if (tmp->rdev
+ && tmp->rdev->recovery_offset == MaxSector
+ && !test_bit(Faulty, &tmp->rdev->flags)
+ && !test_and_set_bit(In_sync, &tmp->rdev->flags)) {
+ count++;
+ sysfs_notify_dirent_safe(tmp->rdev->sysfs_state);
+ }
+ }
+ spin_lock_irqsave(&conf->device_lock, flags);
+ mddev->degraded = calc_degraded(conf);
+ spin_unlock_irqrestore(&conf->device_lock, flags);
+ print_raid5_conf(conf);
+ return count;
+}
+
+static int raid5_remove_disk(struct mddev *mddev, struct md_rdev *rdev)
+{
+ struct r5conf *conf = mddev->private;
+ int err = 0;
+ int number = rdev->raid_disk;
+ struct md_rdev **rdevp;
+ struct disk_info *p = conf->disks + number;
+
+ print_raid5_conf(conf);
+ if (rdev == p->rdev)
+ rdevp = &p->rdev;
+ else if (rdev == p->replacement)
+ rdevp = &p->replacement;
+ else
+ return 0;
+
+ if (number >= conf->raid_disks &&
+ conf->reshape_progress == MaxSector)
+ clear_bit(In_sync, &rdev->flags);
+
+ if (test_bit(In_sync, &rdev->flags) ||
+ atomic_read(&rdev->nr_pending)) {
+ err = -EBUSY;
+ goto abort;
+ }
+ /* Only remove non-faulty devices if recovery
+ * isn't possible.
+ */
+ if (!test_bit(Faulty, &rdev->flags) &&
+ mddev->recovery_disabled != conf->recovery_disabled &&
+ !has_failed(conf) &&
+ (!p->replacement || p->replacement == rdev) &&
+ number < conf->raid_disks) {
+ err = -EBUSY;
+ goto abort;
+ }
+ *rdevp = NULL;
+ synchronize_rcu();
+ if (atomic_read(&rdev->nr_pending)) {
+ /* lost the race, try later */
+ err = -EBUSY;
+ *rdevp = rdev;
+ } else if (p->replacement) {
+ /* We must have just cleared 'rdev' */
+ p->rdev = p->replacement;
+ clear_bit(Replacement, &p->replacement->flags);
+ smp_mb(); /* Make sure other CPUs may see both as identical
+ * but will never see neither - if they are careful
+ */
+ p->replacement = NULL;
+ clear_bit(WantReplacement, &rdev->flags);
+ } else
+ /* We might have just removed the Replacement as faulty-
+ * clear the bit just in case
+ */
+ clear_bit(WantReplacement, &rdev->flags);
+abort:
+
+ print_raid5_conf(conf);
+ return err;
+}
+
+static int raid5_add_disk(struct mddev *mddev, struct md_rdev *rdev)
+{
+ struct r5conf *conf = mddev->private;
+ int err = -EEXIST;
+ int disk;
+ struct disk_info *p;
+ int first = 0;
+ int last = conf->raid_disks - 1;
+
+ if (mddev->recovery_disabled == conf->recovery_disabled)
+ return -EBUSY;
+
+ if (rdev->saved_raid_disk < 0 && has_failed(conf))
+ /* 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)
+ first = rdev->saved_raid_disk;
+
+ for (disk = first; disk <= last; disk++) {
+ p = conf->disks + disk;
+ if (p->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);
+ goto out;
+ }
+ }
+ for (disk = first; disk <= last; disk++) {
+ p = conf->disks + disk;
+ if (test_bit(WantReplacement, &p->rdev->flags) &&
+ p->replacement == NULL) {
+ clear_bit(In_sync, &rdev->flags);
+ set_bit(Replacement, &rdev->flags);
+ rdev->raid_disk = disk;
+ err = 0;
+ conf->fullsync = 1;
+ rcu_assign_pointer(p->replacement, rdev);
+ break;
+ }
+ }
+out:
+ print_raid5_conf(conf);
+ return err;
+}
+
+static int raid5_resize(struct mddev *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.
+ */
+ sector_t newsize;
+ sectors &= ~((sector_t)mddev->chunk_sectors - 1);
+ newsize = raid5_size(mddev, sectors, mddev->raid_disks);
+ if (mddev->external_size &&
+ mddev->array_sectors > newsize)
+ return -EINVAL;
+ if (mddev->bitmap) {
+ int ret = bitmap_resize(mddev->bitmap, sectors, 0, 0);
+ if (ret)
+ return ret;
+ }
+ md_set_array_sectors(mddev, newsize);
+ set_capacity(mddev->gendisk, mddev->array_sectors);
+ revalidate_disk(mddev->gendisk);
+ if (sectors > mddev->dev_sectors &&
+ mddev->recovery_cp > mddev->dev_sectors) {
+ mddev->recovery_cp = mddev->dev_sectors;
+ set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
+ }
+ mddev->dev_sectors = sectors;
+ mddev->resync_max_sectors = sectors;
+ return 0;
+}
+
+static int check_stripe_cache(struct mddev *mddev)
+{
+ /* 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.
+ */
+ struct r5conf *conf = mddev->private;
+ if (((mddev->chunk_sectors << 9) / STRIPE_SIZE) * 4
+ > conf->min_nr_stripes ||
+ ((mddev->new_chunk_sectors << 9) / STRIPE_SIZE) * 4
+ > conf->min_nr_stripes) {
+ printk(KERN_WARNING "md/raid:%s: reshape: not enough stripes. Needed %lu\n",
+ mdname(mddev),
+ ((max(mddev->chunk_sectors, mddev->new_chunk_sectors) << 9)
+ / STRIPE_SIZE)*4);
+ return 0;
+ }
+ return 1;
+}
+
+static int check_reshape(struct mddev *mddev)
+{
+ struct r5conf *conf = mddev->private;
+
+ if (mddev->delta_disks == 0 &&
+ mddev->new_layout == mddev->layout &&
+ mddev->new_chunk_sectors == mddev->chunk_sectors)
+ return 0; /* nothing to do */
+ if (has_failed(conf))
+ return -EINVAL;
+ if (mddev->delta_disks < 0 && mddev->reshape_position == MaxSector) {
+ /* We might be able to shrink, but the devices must
+ * be made bigger first.
+ * For raid6, 4 is the minimum size.
+ * Otherwise 2 is the minimum
+ */
+ int min = 2;
+ if (mddev->level == 6)
+ min = 4;
+ if (mddev->raid_disks + mddev->delta_disks < min)
+ return -EINVAL;
+ }
+
+ if (!check_stripe_cache(mddev))
+ return -ENOSPC;
+
+ if (mddev->new_chunk_sectors > mddev->chunk_sectors ||
+ mddev->delta_disks > 0)
+ if (resize_chunks(conf,
+ conf->previous_raid_disks
+ + max(0, mddev->delta_disks),
+ max(mddev->new_chunk_sectors,
+ mddev->chunk_sectors)
+ ) < 0)
+ return -ENOMEM;
+ return resize_stripes(conf, (conf->previous_raid_disks
+ + mddev->delta_disks));
+}
+
+static int raid5_start_reshape(struct mddev *mddev)
+{
+ struct r5conf *conf = mddev->private;
+ struct md_rdev *rdev;
+ int spares = 0;
+ unsigned long flags;
+
+ if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery))
+ return -EBUSY;
+
+ if (!check_stripe_cache(mddev))
+ return -ENOSPC;
+
+ if (has_failed(conf))
+ return -EINVAL;
+
+ rdev_for_each(rdev, mddev) {
+ if (!test_bit(In_sync, &rdev->flags)
+ && !test_bit(Faulty, &rdev->flags))
+ spares++;
+ }
+
+ if (spares - mddev->degraded < mddev->delta_disks - conf->max_degraded)
+ /* Not enough devices even to make a degraded array
+ * of that size
+ */
+ return -EINVAL;
+
+ /* Refuse to reduce size of the array. Any reductions in
+ * array size must be through explicit setting of array_size
+ * attribute.
+ */
+ if (raid5_size(mddev, 0, conf->raid_disks + mddev->delta_disks)
+ < mddev->array_sectors) {
+ printk(KERN_ERR "md/raid:%s: array size must be reduced "
+ "before number of disks\n", mdname(mddev));
+ return -EINVAL;
+ }
+
+ atomic_set(&conf->reshape_stripes, 0);
+ spin_lock_irq(&conf->device_lock);
+ write_seqcount_begin(&conf->gen_lock);
+ conf->previous_raid_disks = conf->raid_disks;
+ conf->raid_disks += mddev->delta_disks;
+ conf->prev_chunk_sectors = conf->chunk_sectors;
+ conf->chunk_sectors = mddev->new_chunk_sectors;
+ conf->prev_algo = conf->algorithm;
+ conf->algorithm = mddev->new_layout;
+ conf->generation++;
+ /* Code that selects data_offset needs to see the generation update
+ * if reshape_progress has been set - so a memory barrier needed.
+ */
+ smp_mb();
+ if (mddev->reshape_backwards)
+ conf->reshape_progress = raid5_size(mddev, 0, 0);
+ else
+ conf->reshape_progress = 0;
+ conf->reshape_safe = conf->reshape_progress;
+ write_seqcount_end(&conf->gen_lock);
+ spin_unlock_irq(&conf->device_lock);
+
+ /* Now make sure any requests that proceeded on the assumption
+ * the reshape wasn't running - like Discard or Read - have
+ * completed.
+ */
+ mddev_suspend(mddev);
+ mddev_resume(mddev);
+
+ /* Add some new drives, as many as will fit.
+ * We know there are enough to make the newly sized array work.
+ * Don't add devices if we are reducing the number of
+ * devices in the array. This is because it is not possible
+ * to correctly record the "partially reconstructed" state of
+ * such devices during the reshape and confusion could result.
+ */
+ if (mddev->delta_disks >= 0) {
+ rdev_for_each(rdev, mddev)
+ if (rdev->raid_disk < 0 &&
+ !test_bit(Faulty, &rdev->flags)) {
+ if (raid5_add_disk(mddev, rdev) == 0) {
+ if (rdev->raid_disk
+ >= conf->previous_raid_disks)
+ set_bit(In_sync, &rdev->flags);
+ else
+ rdev->recovery_offset = 0;
+
+ if (sysfs_link_rdev(mddev, rdev))
+ /* Failure here is OK */;
+ }
+ } else if (rdev->raid_disk >= conf->previous_raid_disks
+ && !test_bit(Faulty, &rdev->flags)) {
+ /* This is a spare that was manually added */
+ set_bit(In_sync, &rdev->flags);
+ }
+
+ /* When a reshape changes the number of devices,
+ * ->degraded is measured against the larger of the
+ * pre and post number of devices.
+ */
+ spin_lock_irqsave(&conf->device_lock, flags);
+ mddev->degraded = calc_degraded(conf);
+ spin_unlock_irqrestore(&conf->device_lock, flags);
+ }
+ mddev->raid_disks = conf->raid_disks;
+ mddev->reshape_position = conf->reshape_progress;
+ set_bit(MD_CHANGE_DEVS, &mddev->flags);
+
+ clear_bit(MD_RECOVERY_SYNC, &mddev->recovery);
+ clear_bit(MD_RECOVERY_CHECK, &mddev->recovery);
+ clear_bit(MD_RECOVERY_DONE, &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,
+ "reshape");
+ if (!mddev->sync_thread) {
+ mddev->recovery = 0;
+ spin_lock_irq(&conf->device_lock);
+ write_seqcount_begin(&conf->gen_lock);
+ mddev->raid_disks = conf->raid_disks = conf->previous_raid_disks;
+ mddev->new_chunk_sectors =
+ conf->chunk_sectors = conf->prev_chunk_sectors;
+ mddev->new_layout = conf->algorithm = conf->prev_algo;
+ rdev_for_each(rdev, mddev)
+ rdev->new_data_offset = rdev->data_offset;
+ smp_wmb();
+ conf->generation --;
+ conf->reshape_progress = MaxSector;
+ mddev->reshape_position = MaxSector;
+ write_seqcount_end(&conf->gen_lock);
+ spin_unlock_irq(&conf->device_lock);
+ return -EAGAIN;
+ }
+ conf->reshape_checkpoint = jiffies;
+ md_wakeup_thread(mddev->sync_thread);
+ md_new_event(mddev);
+ return 0;
+}
+
+/* This is called from the reshape thread and should make any
+ * changes needed in 'conf'
+ */
+static void end_reshape(struct r5conf *conf)
+{
+
+ if (!test_bit(MD_RECOVERY_INTR, &conf->mddev->recovery)) {
+ struct md_rdev *rdev;
+
+ spin_lock_irq(&conf->device_lock);
+ conf->previous_raid_disks = conf->raid_disks;
+ rdev_for_each(rdev, conf->mddev)
+ rdev->data_offset = rdev->new_data_offset;
+ smp_wmb();
+ conf->reshape_progress = MaxSector;
+ spin_unlock_irq(&conf->device_lock);
+ wake_up(&conf->wait_for_overlap);
+
+ /* read-ahead size must cover two whole stripes, which is
+ * 2 * (datadisks) * chunksize where 'n' is the number of raid devices
+ */
+ if (conf->mddev->queue) {
+ int data_disks = conf->raid_disks - conf->max_degraded;
+ int stripe = data_disks * ((conf->chunk_sectors << 9)
+ / PAGE_SIZE);
+ if (conf->mddev->queue->backing_dev_info.ra_pages < 2 * stripe)
+ conf->mddev->queue->backing_dev_info.ra_pages = 2 * stripe;
+ }
+ }
+}
+
+/* This is called from the raid5d thread with mddev_lock held.
+ * It makes config changes to the device.
+ */
+static void raid5_finish_reshape(struct mddev *mddev)
+{
+ struct r5conf *conf = mddev->private;
+
+ if (!test_bit(MD_RECOVERY_INTR, &mddev->recovery)) {
+
+ if (mddev->delta_disks > 0) {
+ md_set_array_sectors(mddev, raid5_size(mddev, 0, 0));
+ set_capacity(mddev->gendisk, mddev->array_sectors);
+ revalidate_disk(mddev->gendisk);
+ } else {
+ int d;
+ spin_lock_irq(&conf->device_lock);
+ mddev->degraded = calc_degraded(conf);
+ spin_unlock_irq(&conf->device_lock);
+ for (d = conf->raid_disks ;
+ d < conf->raid_disks - mddev->delta_disks;
+ d++) {
+ struct md_rdev *rdev = conf->disks[d].rdev;
+ if (rdev)
+ clear_bit(In_sync, &rdev->flags);
+ rdev = conf->disks[d].replacement;
+ if (rdev)
+ clear_bit(In_sync, &rdev->flags);
+ }
+ }
+ mddev->layout = conf->algorithm;
+ mddev->chunk_sectors = conf->chunk_sectors;
+ mddev->reshape_position = MaxSector;
+ mddev->delta_disks = 0;
+ mddev->reshape_backwards = 0;
+ }
+}
+
+static void raid5_quiesce(struct mddev *mddev, int state)
+{
+ struct r5conf *conf = mddev->private;
+
+ switch(state) {
+ case 2: /* resume for a suspend */
+ wake_up(&conf->wait_for_overlap);
+ break;
+
+ case 1: /* stop all writes */
+ lock_all_device_hash_locks_irq(conf);
+ /* '2' tells resync/reshape to pause so that all
+ * active stripes can drain
+ */
+ conf->quiesce = 2;
+ wait_event_cmd(conf->wait_for_stripe,
+ atomic_read(&conf->active_stripes) == 0 &&
+ atomic_read(&conf->active_aligned_reads) == 0,
+ unlock_all_device_hash_locks_irq(conf),
+ lock_all_device_hash_locks_irq(conf));
+ conf->quiesce = 1;
+ unlock_all_device_hash_locks_irq(conf);
+ /* allow reshape to continue */
+ wake_up(&conf->wait_for_overlap);
+ break;
+
+ case 0: /* re-enable writes */
+ lock_all_device_hash_locks_irq(conf);
+ conf->quiesce = 0;
+ wake_up(&conf->wait_for_stripe);
+ wake_up(&conf->wait_for_overlap);
+ unlock_all_device_hash_locks_irq(conf);
+ break;
+ }
+}
+
+static void *raid45_takeover_raid0(struct mddev *mddev, int level)
+{
+ struct r0conf *raid0_conf = mddev->private;
+ sector_t sectors;
+
+ /* for raid0 takeover only one zone is supported */
+ if (raid0_conf->nr_strip_zones > 1) {
+ printk(KERN_ERR "md/raid:%s: cannot takeover raid0 with more than one zone.\n",
+ mdname(mddev));
+ return ERR_PTR(-EINVAL);
+ }
+
+ sectors = raid0_conf->strip_zone[0].zone_end;
+ sector_div(sectors, raid0_conf->strip_zone[0].nb_dev);
+ mddev->dev_sectors = sectors;
+ mddev->new_level = level;
+ mddev->new_layout = ALGORITHM_PARITY_N;
+ mddev->new_chunk_sectors = mddev->chunk_sectors;
+ mddev->raid_disks += 1;
+ mddev->delta_disks = 1;
+ /* make sure it will be not marked as dirty */
+ mddev->recovery_cp = MaxSector;
+
+ return setup_conf(mddev);
+}
+
+static void *raid5_takeover_raid1(struct mddev *mddev)
+{
+ int chunksect;
+
+ if (mddev->raid_disks != 2 ||
+ mddev->degraded > 1)
+ return ERR_PTR(-EINVAL);
+
+ /* Should check if there are write-behind devices? */
+
+ chunksect = 64*2; /* 64K by default */
+
+ /* The array must be an exact multiple of chunksize */
+ while (chunksect && (mddev->array_sectors & (chunksect-1)))
+ chunksect >>= 1;
+
+ if ((chunksect<<9) < STRIPE_SIZE)
+ /* array size does not allow a suitable chunk size */
+ return ERR_PTR(-EINVAL);
+
+ mddev->new_level = 5;
+ mddev->new_layout = ALGORITHM_LEFT_SYMMETRIC;
+ mddev->new_chunk_sectors = chunksect;
+
+ return setup_conf(mddev);
+}
+
+static void *raid5_takeover_raid6(struct mddev *mddev)
+{
+ int new_layout;
+
+ switch (mddev->layout) {
+ case ALGORITHM_LEFT_ASYMMETRIC_6:
+ new_layout = ALGORITHM_LEFT_ASYMMETRIC;
+ break;
+ case ALGORITHM_RIGHT_ASYMMETRIC_6:
+ new_layout = ALGORITHM_RIGHT_ASYMMETRIC;
+ break;
+ case ALGORITHM_LEFT_SYMMETRIC_6:
+ new_layout = ALGORITHM_LEFT_SYMMETRIC;
+ break;
+ case ALGORITHM_RIGHT_SYMMETRIC_6:
+ new_layout = ALGORITHM_RIGHT_SYMMETRIC;
+ break;
+ case ALGORITHM_PARITY_0_6:
+ new_layout = ALGORITHM_PARITY_0;
+ break;
+ case ALGORITHM_PARITY_N:
+ new_layout = ALGORITHM_PARITY_N;
+ break;
+ default:
+ return ERR_PTR(-EINVAL);
+ }
+ mddev->new_level = 5;
+ mddev->new_layout = new_layout;
+ mddev->delta_disks = -1;
+ mddev->raid_disks -= 1;
+ return setup_conf(mddev);
+}
+
+static int raid5_check_reshape(struct mddev *mddev)
+{
+ /* For a 2-drive array, the layout and chunk size can be changed
+ * immediately as not restriping is needed.
+ * For larger arrays we record the new value - after validation
+ * to be used by a reshape pass.
+ */
+ struct r5conf *conf = mddev->private;
+ int new_chunk = mddev->new_chunk_sectors;
+
+ if (mddev->new_layout >= 0 && !algorithm_valid_raid5(mddev->new_layout))
+ return -EINVAL;
+ if (new_chunk > 0) {
+ if (!is_power_of_2(new_chunk))
+ return -EINVAL;
+ if (new_chunk < (PAGE_SIZE>>9))
+ return -EINVAL;
+ if (mddev->array_sectors & (new_chunk-1))
+ /* not factor of array size */
+ return -EINVAL;
+ }
+
+ /* They look valid */
+
+ if (mddev->raid_disks == 2) {
+ /* can make the change immediately */
+ if (mddev->new_layout >= 0) {
+ conf->algorithm = mddev->new_layout;
+ mddev->layout = mddev->new_layout;
+ }
+ if (new_chunk > 0) {
+ conf->chunk_sectors = new_chunk ;
+ mddev->chunk_sectors = new_chunk;
+ }
+ set_bit(MD_CHANGE_DEVS, &mddev->flags);
+ md_wakeup_thread(mddev->thread);
+ }
+ return check_reshape(mddev);
+}
+
+static int raid6_check_reshape(struct mddev *mddev)
+{
+ int new_chunk = mddev->new_chunk_sectors;
+
+ if (mddev->new_layout >= 0 && !algorithm_valid_raid6(mddev->new_layout))
+ return -EINVAL;
+ if (new_chunk > 0) {
+ if (!is_power_of_2(new_chunk))
+ return -EINVAL;
+ if (new_chunk < (PAGE_SIZE >> 9))
+ return -EINVAL;
+ if (mddev->array_sectors & (new_chunk-1))
+ /* not factor of array size */
+ return -EINVAL;
+ }
+
+ /* They look valid */
+ return check_reshape(mddev);
+}
+
+static void *raid5_takeover(struct mddev *mddev)
+{
+ /* raid5 can take over:
+ * raid0 - if there is only one strip zone - make it a raid4 layout
+ * raid1 - if there are two drives. We need to know the chunk size
+ * raid4 - trivial - just use a raid4 layout.
+ * raid6 - Providing it is a *_6 layout
+ */
+ if (mddev->level == 0)
+ return raid45_takeover_raid0(mddev, 5);
+ if (mddev->level == 1)
+ return raid5_takeover_raid1(mddev);
+ if (mddev->level == 4) {
+ mddev->new_layout = ALGORITHM_PARITY_N;
+ mddev->new_level = 5;
+ return setup_conf(mddev);
+ }
+ if (mddev->level == 6)
+ return raid5_takeover_raid6(mddev);
+
+ return ERR_PTR(-EINVAL);
+}
+
+static void *raid4_takeover(struct mddev *mddev)
+{
+ /* raid4 can take over:
+ * raid0 - if there is only one strip zone
+ * raid5 - if layout is right
+ */
+ if (mddev->level == 0)
+ return raid45_takeover_raid0(mddev, 4);
+ if (mddev->level == 5 &&
+ mddev->layout == ALGORITHM_PARITY_N) {
+ mddev->new_layout = 0;
+ mddev->new_level = 4;
+ return setup_conf(mddev);
+ }
+ return ERR_PTR(-EINVAL);
+}
+
+static struct md_personality raid5_personality;
+
+static void *raid6_takeover(struct mddev *mddev)
+{
+ /* Currently can only take over a raid5. We map the
+ * personality to an equivalent raid6 personality
+ * with the Q block at the end.
+ */
+ int new_layout;
+
+ if (mddev->pers != &raid5_personality)
+ return ERR_PTR(-EINVAL);
+ if (mddev->degraded > 1)
+ return ERR_PTR(-EINVAL);
+ if (mddev->raid_disks > 253)
+ return ERR_PTR(-EINVAL);
+ if (mddev->raid_disks < 3)
+ return ERR_PTR(-EINVAL);
+
+ switch (mddev->layout) {
+ case ALGORITHM_LEFT_ASYMMETRIC:
+ new_layout = ALGORITHM_LEFT_ASYMMETRIC_6;
+ break;
+ case ALGORITHM_RIGHT_ASYMMETRIC:
+ new_layout = ALGORITHM_RIGHT_ASYMMETRIC_6;
+ break;
+ case ALGORITHM_LEFT_SYMMETRIC:
+ new_layout = ALGORITHM_LEFT_SYMMETRIC_6;
+ break;
+ case ALGORITHM_RIGHT_SYMMETRIC:
+ new_layout = ALGORITHM_RIGHT_SYMMETRIC_6;
+ break;
+ case ALGORITHM_PARITY_0:
+ new_layout = ALGORITHM_PARITY_0_6;
+ break;
+ case ALGORITHM_PARITY_N:
+ new_layout = ALGORITHM_PARITY_N;
+ break;
+ default:
+ return ERR_PTR(-EINVAL);
+ }
+ mddev->new_level = 6;
+ mddev->new_layout = new_layout;
+ mddev->delta_disks = 1;
+ mddev->raid_disks += 1;
+ return setup_conf(mddev);
+}
+
+static struct md_personality raid6_personality =
+{
+ .name = "raid6",
+ .level = 6,
+ .owner = THIS_MODULE,
+ .make_request = make_request,
+ .run = run,
+ .free = raid5_free,
+ .status = status,
+ .error_handler = error,
+ .hot_add_disk = raid5_add_disk,
+ .hot_remove_disk= raid5_remove_disk,
+ .spare_active = raid5_spare_active,
+ .sync_request = sync_request,
+ .resize = raid5_resize,
+ .size = raid5_size,
+ .check_reshape = raid6_check_reshape,
+ .start_reshape = raid5_start_reshape,
+ .finish_reshape = raid5_finish_reshape,
+ .quiesce = raid5_quiesce,
+ .takeover = raid6_takeover,
+ .congested = raid5_congested,
+ .mergeable_bvec = raid5_mergeable_bvec,
+};
+static struct md_personality raid5_personality =
+{
+ .name = "raid5",
+ .level = 5,
+ .owner = THIS_MODULE,
+ .make_request = make_request,
+ .run = run,
+ .free = raid5_free,
+ .status = status,
+ .error_handler = error,
+ .hot_add_disk = raid5_add_disk,
+ .hot_remove_disk= raid5_remove_disk,
+ .spare_active = raid5_spare_active,
+ .sync_request = sync_request,
+ .resize = raid5_resize,
+ .size = raid5_size,
+ .check_reshape = raid5_check_reshape,
+ .start_reshape = raid5_start_reshape,
+ .finish_reshape = raid5_finish_reshape,
+ .quiesce = raid5_quiesce,
+ .takeover = raid5_takeover,
+ .congested = raid5_congested,
+ .mergeable_bvec = raid5_mergeable_bvec,
+};
+
+static struct md_personality raid4_personality =
+{
+ .name = "raid4",
+ .level = 4,
+ .owner = THIS_MODULE,
+ .make_request = make_request,
+ .run = run,
+ .free = raid5_free,
+ .status = status,
+ .error_handler = error,
+ .hot_add_disk = raid5_add_disk,
+ .hot_remove_disk= raid5_remove_disk,
+ .spare_active = raid5_spare_active,
+ .sync_request = sync_request,
+ .resize = raid5_resize,
+ .size = raid5_size,
+ .check_reshape = raid5_check_reshape,
+ .start_reshape = raid5_start_reshape,
+ .finish_reshape = raid5_finish_reshape,
+ .quiesce = raid5_quiesce,
+ .takeover = raid4_takeover,
+ .congested = raid5_congested,
+ .mergeable_bvec = raid5_mergeable_bvec,
+};
+
+static int __init raid5_init(void)
+{
+ raid5_wq = alloc_workqueue("raid5wq",
+ WQ_UNBOUND|WQ_MEM_RECLAIM|WQ_CPU_INTENSIVE|WQ_SYSFS, 0);
+ if (!raid5_wq)
+ return -ENOMEM;
+ 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);
+ destroy_workqueue(raid5_wq);
+}
+
+module_init(raid5_init);
+module_exit(raid5_exit);
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("RAID4/5/6 (striping with parity) personality for MD");
+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");
Code Review / kvmfornfv.git / blobdiff