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raid5.c
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/*
* 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 <linux/list_sort.h>
#include "md.h"
#include "raid5.h"
#include "raid0.h"
#include "md-bitmap.h"
#include "raid5-log.h"
#define UNSUPPORTED_MDDEV_FLAGS (1L << MD_FAILFAST_SUPPORTED)
#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;
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;
spin_lock_irq(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 - 1; i; i--)
spin_unlock(conf->hash_locks + i);
spin_unlock_irq(conf->hash_locks);
}
/* 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 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 bool stripe_is_lowprio(struct stripe_head *sh)
{
return (test_bit(STRIPE_R5C_FULL_STRIPE, &sh->state) ||
test_bit(STRIPE_R5C_PARTIAL_STRIPE, &sh->state)) &&
!test_bit(STRIPE_R5C_CACHING, &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);
if (stripe_is_lowprio(sh))
list_add_tail(&sh->lru, &group->loprio_list);
else
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)
{
int i;
int injournal = 0; /* number of date pages with R5_InJournal */
BUG_ON(!list_empty(&sh->lru));
BUG_ON(atomic_read(&conf->active_stripes)==0);
if (r5c_is_writeback(conf->log))
for (i = sh->disks; i--; )
if (test_bit(R5_InJournal, &sh->dev[i].flags))
injournal++;
/*
* In the following cases, the stripe cannot be released to cached
* lists. Therefore, we make the stripe write out and set
* STRIPE_HANDLE:
* 1. when quiesce in r5c write back;
* 2. when resync is requested fot the stripe.
*/
if (test_bit(STRIPE_SYNC_REQUESTED, &sh->state) ||
(conf->quiesce && r5c_is_writeback(conf->log) &&
!test_bit(STRIPE_HANDLE, &sh->state) && injournal != 0)) {
if (test_bit(STRIPE_R5C_CACHING, &sh->state))
r5c_make_stripe_write_out(sh);
set_bit(STRIPE_HANDLE, &sh->state);
}
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) {
if (stripe_is_lowprio(sh))
list_add_tail(&sh->lru,
&conf->loprio_list);
else
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)) {
if (!r5c_is_writeback(conf->log))
list_add_tail(&sh->lru, temp_inactive_list);
else {
WARN_ON(test_bit(R5_InJournal, &sh->dev[sh->pd_idx].flags));
if (injournal == 0)
list_add_tail(&sh->lru, temp_inactive_list);
else if (injournal == conf->raid_disks - conf->max_degraded) {
/* full stripe */
if (!test_and_set_bit(STRIPE_R5C_FULL_STRIPE, &sh->state))
atomic_inc(&conf->r5c_cached_full_stripes);
if (test_and_clear_bit(STRIPE_R5C_PARTIAL_STRIPE, &sh->state))
atomic_dec(&conf->r5c_cached_partial_stripes);
list_add_tail(&sh->lru, &conf->r5c_full_stripe_list);
r5c_check_cached_full_stripe(conf);
} else
/*
* STRIPE_R5C_PARTIAL_STRIPE is set in
* r5c_try_caching_write(). No need to
* set it again.
*/
list_add_tail(&sh->lru, &conf->r5c_partial_stripe_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, raid5_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 (atomic_read(&conf->active_stripes) == 0)
wake_up(&conf->wait_for_quiescent);
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, *t;
int count = 0;
struct llist_node *head;
head = llist_del_all(&conf->released_stripes);
head = llist_reverse_order(head);
llist_for_each_entry_safe(sh, t, head, release_list) {
int hash;
/* 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;
}
void raid5_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 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)) {
pr_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;
dev->sector = raid5_compute_blocknr(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.
*/
int raid5_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 = raid5_calc_degraded(conf);
if (degraded > conf->max_degraded)
return 1;
return 0;
}
struct stripe_head *
raid5_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);
int inc_empty_inactive_list_flag;
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_quiescent,
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 && !test_bit(R5_DID_ALLOC,
&conf->cache_state))
set_bit(R5_ALLOC_MORE,
&conf->cache_state);
}
if (noblock && sh == NULL)
break;
r5c_check_stripe_cache_usage(conf);
if (!sh) {
set_bit(R5_INACTIVE_BLOCKED,
&conf->cache_state);
r5l_wake_reclaim(conf->log, 0);
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));
inc_empty_inactive_list_flag = 0;
if (!list_empty(conf->inactive_list + hash))
inc_empty_inactive_list_flag = 1;
list_del_init(&sh->lru);
if (list_empty(conf->inactive_list + hash) && inc_empty_inactive_list_flag)
atomic_inc(&conf->empty_inactive_list_nr);
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)
{
if (sh1 > sh2) {
spin_lock_irq(&sh2->stripe_lock);
spin_lock_nested(&sh1->stripe_lock, 1);
} else {
spin_lock_irq(&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_irq(&sh2->stripe_lock);
}
/* Only freshly new full stripe normal write stripe can be added to a batch list */
static bool stripe_can_batch(struct stripe_head *sh)
{
struct r5conf *conf = sh->raid_conf;
if (conf->log || raid5_has_ppl(conf))
return false;
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;
int inc_empty_inactive_list_flag;
/* 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));
inc_empty_inactive_list_flag = 0;
if (!list_empty(conf->inactive_list + hash))
inc_empty_inactive_list_flag = 1;
list_del_init(&head->lru);
if (list_empty(conf->inactive_list + hash) && inc_empty_inactive_list_flag)
atomic_inc(&conf->empty_inactive_list_nr);
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_opf != sh->dev[dd_idx].towrite->bi_opf ||
bio_op(head->dev[dd_idx].towrite) != bio_op(sh->dev[dd_idx].towrite))
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;
}
/*
* We must assign batch_head of this stripe within the
* batch_lock, otherwise clear_batch_ready of batch head
* stripe could clear BATCH_READY bit of this stripe and
* this stripe->batch_head doesn't get assigned, which
* could confuse clear_batch_ready for this stripe
*/
sh->batch_head = head->batch_head;
/*
* 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);
} 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:
raid5_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 dispatch_bio_list(struct bio_list *tmp)
{
struct bio *bio;
while ((bio = bio_list_pop(tmp)))
generic_make_request(bio);
}
static int cmp_stripe(void *priv, struct list_head *a, struct list_head *b)
{
const struct r5pending_data *da = list_entry(a,
struct r5pending_data, sibling);
const struct r5pending_data *db = list_entry(b,
struct r5pending_data, sibling);
if (da->sector > db->sector)
return 1;
if (da->sector < db->sector)
return -1;
return 0;
}
static void dispatch_defer_bios(struct r5conf *conf, int target,
struct bio_list *list)
{
struct r5pending_data *data;
struct list_head *first, *next = NULL;
int cnt = 0;
if (conf->pending_data_cnt == 0)
return;
list_sort(NULL, &conf->pending_list, cmp_stripe);
first = conf->pending_list.next;
/* temporarily move the head */
if (conf->next_pending_data)
list_move_tail(&conf->pending_list,
&conf->next_pending_data->sibling);
while (!list_empty(&conf->pending_list)) {
data = list_first_entry(&conf->pending_list,
struct r5pending_data, sibling);
if (&data->sibling == first)
first = data->sibling.next;
next = data->sibling.next;
bio_list_merge(list, &data->bios);
list_move(&data->sibling, &conf->free_list);
cnt++;
if (cnt >= target)
break;
}
conf->pending_data_cnt -= cnt;
BUG_ON(conf->pending_data_cnt < 0 || cnt < target);
if (next != &conf->pending_list)
conf->next_pending_data = list_entry(next,
struct r5pending_data, sibling);
else
conf->next_pending_data = NULL;
/* list isn't empty */
if (first != &conf->pending_list)
list_move_tail(&conf->pending_list, first);
}
static void flush_deferred_bios(struct r5conf *conf)
{
struct bio_list tmp = BIO_EMPTY_LIST;
if (conf->pending_data_cnt == 0)
return;
spin_lock(&conf->pending_bios_lock);
dispatch_defer_bios(conf, conf->pending_data_cnt, &tmp);
BUG_ON(conf->pending_data_cnt != 0);
spin_unlock(&conf->pending_bios_lock);
dispatch_bio_list(&tmp);
}
static void defer_issue_bios(struct r5conf *conf, sector_t sector,
struct bio_list *bios)
{
struct bio_list tmp = BIO_EMPTY_LIST;
struct r5pending_data *ent;
spin_lock(&conf->pending_bios_lock);
ent = list_first_entry(&conf->free_list, struct r5pending_data,
sibling);
list_move_tail(&ent->sibling, &conf->pending_list);
ent->sector = sector;
bio_list_init(&ent->bios);
bio_list_merge(&ent->bios, bios);
conf->pending_data_cnt++;
if (conf->pending_data_cnt >= PENDING_IO_MAX)
dispatch_defer_bios(conf, PENDING_IO_ONE_FLUSH, &tmp);
spin_unlock(&conf->pending_bios_lock);
dispatch_bio_list(&tmp);
}
static void
raid5_end_read_request(struct bio *bi);
static void
raid5_end_write_request(struct bio *bi);
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;
struct bio_list pending_bios = BIO_EMPTY_LIST;
bool should_defer;
might_sleep();
if (log_stripe(sh, s) == 0)
return;
should_defer = conf->batch_bio_dispatch && conf->group_cnt;