- directory with info about Linux on Motorola 68k architecture.
mailbox.txt
- How to write drivers for the common mailbox framework (IPC).
-md-cluster.txt
- - info on shared-device RAID MD cluster.
+md/
+ - directory with info about Linux Software RAID
media/
- info on media drivers: uAPI, kAPI and driver documentation.
memory-barriers.txt
to 1. Setting this to 0 disables bypass accounting and
requires preread stripes to wait until all full-width stripe-
writes are complete. Valid values are 0 to stripe_cache_size.
+
+ journal_mode (currently raid5 only)
+ The cache mode for raid5. raid5 could include an extra disk for
+ caching. The mode can be "write-throuth" and "write-back". The
+ default is "write-through".
--- /dev/null
+RAID5 cache
+
+Raid 4/5/6 could include an extra disk for data cache besides normal RAID
+disks. The role of RAID disks isn't changed with the cache disk. The cache disk
+caches data to the RAID disks. The cache can be in write-through (supported
+since 4.4) or write-back mode (supported since 4.10). mdadm (supported since
+3.4) has a new option '--write-journal' to create array with cache. Please
+refer to mdadm manual for details. By default (RAID array starts), the cache is
+in write-through mode. A user can switch it to write-back mode by:
+
+echo "write-back" > /sys/block/md0/md/journal_mode
+
+And switch it back to write-through mode by:
+
+echo "write-through" > /sys/block/md0/md/journal_mode
+
+In both modes, all writes to the array will hit cache disk first. This means
+the cache disk must be fast and sustainable.
+
+-------------------------------------
+write-through mode:
+
+This mode mainly fixes the 'write hole' issue. For RAID 4/5/6 array, an unclean
+shutdown can cause data in some stripes to not be in consistent state, eg, data
+and parity don't match. The reason is that a stripe write involves several RAID
+disks and it's possible the writes don't hit all RAID disks yet before the
+unclean shutdown. We call an array degraded if it has inconsistent data. MD
+tries to resync the array to bring it back to normal state. But before the
+resync completes, any system crash will expose the chance of real data
+corruption in the RAID array. This problem is called 'write hole'.
+
+The write-through cache will cache all data on cache disk first. After the data
+is safe on the cache disk, the data will be flushed onto RAID disks. The
+two-step write will guarantee MD can recover correct data after unclean
+shutdown even the array is degraded. Thus the cache can close the 'write hole'.
+
+In write-through mode, MD reports IO completion to upper layer (usually
+filesystems) after the data is safe on RAID disks, so cache disk failure
+doesn't cause data loss. Of course cache disk failure means the array is
+exposed to 'write hole' again.
+
+In write-through mode, the cache disk isn't required to be big. Several
+hundreds megabytes are enough.
+
+--------------------------------------
+write-back mode:
+
+write-back mode fixes the 'write hole' issue too, since all write data is
+cached on cache disk. But the main goal of 'write-back' cache is to speed up
+write. If a write crosses all RAID disks of a stripe, we call it full-stripe
+write. For non-full-stripe writes, MD must read old data before the new parity
+can be calculated. These synchronous reads hurt write throughput. Some writes
+which are sequential but not dispatched in the same time will suffer from this
+overhead too. Write-back cache will aggregate the data and flush the data to
+RAID disks only after the data becomes a full stripe write. This will
+completely avoid the overhead, so it's very helpful for some workloads. A
+typical workload which does sequential write followed by fsync is an example.
+
+In write-back mode, MD reports IO completion to upper layer (usually
+filesystems) right after the data hits cache disk. The data is flushed to raid
+disks later after specific conditions met. So cache disk failure will cause
+data loss.
+
+In write-back mode, MD also caches data in memory. The memory cache includes
+the same data stored on cache disk, so a power loss doesn't cause data loss.
+The memory cache size has performance impact for the array. It's recommended
+the size is big. A user can configure the size by:
+
+echo "2048" > /sys/block/md0/md/stripe_cache_size
+
+Too small cache disk will make the write aggregation less efficient in this
+mode depending on the workloads. It's recommended to use a cache disk with at
+least several gigabytes size in write-back mode.
+
+--------------------------------------
+The implementation:
+
+The write-through and write-back cache use the same disk format. The cache disk
+is organized as a simple write log. The log consists of 'meta data' and 'data'
+pairs. The meta data describes the data. It also includes checksum and sequence
+ID for recovery identification. Data can be IO data and parity data. Data is
+checksumed too. The checksum is stored in the meta data ahead of the data. The
+checksum is an optimization because MD can write meta and data freely without
+worry about the order. MD superblock has a field pointed to the valid meta data
+of log head.
+
+The log implementation is pretty straightforward. The difficult part is the
+order in which MD writes data to cache disk and RAID disks. Specifically, in
+write-through mode, MD calculates parity for IO data, writes both IO data and
+parity to the log, writes the data and parity to RAID disks after the data and
+parity is settled down in log and finally the IO is finished. Read just reads
+from raid disks as usual.
+
+In write-back mode, MD writes IO data to the log and reports IO completion. The
+data is also fully cached in memory at that time, which means read must query
+memory cache. If some conditions are met, MD will flush the data to RAID disks.
+MD will calculate parity for the data and write parity into the log. After this
+is finished, MD will write both data and parity into RAID disks, then MD can
+release the memory cache. The flush conditions could be stripe becomes a full
+stripe write, free cache disk space is low or free in-kernel memory cache space
+is low.
+
+After an unclean shutdown, MD does recovery. MD reads all meta data and data
+from the log. The sequence ID and checksum will help us detect corrupted meta
+data and data. If MD finds a stripe with data and valid parities (1 parity for
+raid4/5 and 2 for raid6), MD will write the data and parities to RAID disks. If
+parities are incompleted, they are discarded. If part of data is corrupted,
+they are discarded too. MD then loads valid data and writes them to RAID disks
+in normal way.
}
EXPORT_SYMBOL(bio_clone_fast);
-/**
- * bio_clone_bioset - clone a bio
- * @bio_src: bio to clone
- * @gfp_mask: allocation priority
- * @bs: bio_set to allocate from
- *
- * Clone bio. Caller will own the returned bio, but not the actual data it
- * points to. Reference count of returned bio will be one.
- */
-struct bio *bio_clone_bioset(struct bio *bio_src, gfp_t gfp_mask,
- struct bio_set *bs)
+static struct bio *__bio_clone_bioset(struct bio *bio_src, gfp_t gfp_mask,
+ struct bio_set *bs, int offset,
+ int size)
{
struct bvec_iter iter;
struct bio_vec bv;
struct bio *bio;
+ struct bvec_iter iter_src = bio_src->bi_iter;
+
+ /* for supporting partial clone */
+ if (offset || size != bio_src->bi_iter.bi_size) {
+ bio_advance_iter(bio_src, &iter_src, offset);
+ iter_src.bi_size = size;
+ }
/*
* Pre immutable biovecs, __bio_clone() used to just do a memcpy from
* __bio_clone_fast() anyways.
*/
- bio = bio_alloc_bioset(gfp_mask, bio_segments(bio_src), bs);
+ bio = bio_alloc_bioset(gfp_mask, __bio_segments(bio_src,
+ &iter_src), bs);
if (!bio)
return NULL;
bio->bi_bdev = bio_src->bi_bdev;
bio->bi_io_vec[bio->bi_vcnt++] = bio_src->bi_io_vec[0];
break;
default:
- bio_for_each_segment(bv, bio_src, iter)
+ __bio_for_each_segment(bv, bio_src, iter, iter_src)
bio->bi_io_vec[bio->bi_vcnt++] = bv;
break;
}
return bio;
}
+
+/**
+ * bio_clone_bioset - clone a bio
+ * @bio_src: bio to clone
+ * @gfp_mask: allocation priority
+ * @bs: bio_set to allocate from
+ *
+ * Clone bio. Caller will own the returned bio, but not the actual data it
+ * points to. Reference count of returned bio will be one.
+ */
+struct bio *bio_clone_bioset(struct bio *bio_src, gfp_t gfp_mask,
+ struct bio_set *bs)
+{
+ return __bio_clone_bioset(bio_src, gfp_mask, bs, 0,
+ bio_src->bi_iter.bi_size);
+}
EXPORT_SYMBOL(bio_clone_bioset);
+/**
+ * bio_clone_bioset_partial - clone a partial bio
+ * @bio_src: bio to clone
+ * @gfp_mask: allocation priority
+ * @bs: bio_set to allocate from
+ * @offset: cloned starting from the offset
+ * @size: size for the cloned bio
+ *
+ * Clone bio. Caller will own the returned bio, but not the actual data it
+ * points to. Reference count of returned bio will be one.
+ */
+struct bio *bio_clone_bioset_partial(struct bio *bio_src, gfp_t gfp_mask,
+ struct bio_set *bs, int offset,
+ int size)
+{
+ return __bio_clone_bioset(bio_src, gfp_mask, bs, offset, size);
+}
+EXPORT_SYMBOL(bio_clone_bioset_partial);
+
/**
* bio_add_pc_page - attempt to add page to bio
* @q: the target queue
}
}
if (failit) {
- struct bio *b = bio_clone_mddev(bio, GFP_NOIO, mddev);
+ struct bio *b = bio_clone_fast(bio, GFP_NOIO, mddev->bio_set);
b->bi_bdev = conf->rdev->bdev;
b->bi_private = bio;
return conf->disks + lo;
}
+/*
+ * In linear_congested() conf->raid_disks is used as a copy of
+ * mddev->raid_disks to iterate conf->disks[], because conf->raid_disks
+ * and conf->disks[] are created in linear_conf(), they are always
+ * consitent with each other, but mddev->raid_disks does not.
+ */
static int linear_congested(struct mddev *mddev, int bits)
{
struct linear_conf *conf;
int i, ret = 0;
- conf = mddev->private;
+ rcu_read_lock();
+ conf = rcu_dereference(mddev->private);
- for (i = 0; i < mddev->raid_disks && !ret ; i++) {
+ for (i = 0; i < conf->raid_disks && !ret ; i++) {
struct request_queue *q = bdev_get_queue(conf->disks[i].rdev->bdev);
ret |= bdi_congested(q->backing_dev_info, bits);
}
+ rcu_read_unlock();
return ret;
}
conf->disks[i-1].end_sector +
conf->disks[i].rdev->sectors;
+ /*
+ * conf->raid_disks is copy of mddev->raid_disks. The reason to
+ * keep a copy of mddev->raid_disks in struct linear_conf is,
+ * mddev->raid_disks may not be consistent with pointers number of
+ * conf->disks[] when it is updated in linear_add() and used to
+ * iterate old conf->disks[] earray in linear_congested().
+ * Here conf->raid_disks is always consitent with number of
+ * pointers in conf->disks[] array, and mddev->private is updated
+ * with rcu_assign_pointer() in linear_addr(), such race can be
+ * avoided.
+ */
+ conf->raid_disks = raid_disks;
+
return conf;
out:
if (!newconf)
return -ENOMEM;
+ /* newconf->raid_disks already keeps a copy of * the increased
+ * value of mddev->raid_disks, WARN_ONCE() is just used to make
+ * sure of this. It is possible that oldconf is still referenced
+ * in linear_congested(), therefore kfree_rcu() is used to free
+ * oldconf until no one uses it anymore.
+ */
mddev_suspend(mddev);
- oldconf = mddev->private;
+ oldconf = rcu_dereference_protected(mddev->private,
+ lockdep_is_held(&mddev->reconfig_mutex));
mddev->raid_disks++;
- mddev->private = newconf;
+ WARN_ONCE(mddev->raid_disks != newconf->raid_disks,
+ "copied raid_disks doesn't match mddev->raid_disks");
+ rcu_assign_pointer(mddev->private, newconf);
md_set_array_sectors(mddev, linear_size(mddev, 0, 0));
set_capacity(mddev->gendisk, mddev->array_sectors);
mddev_resume(mddev);
revalidate_disk(mddev->gendisk);
- kfree(oldconf);
+ kfree_rcu(oldconf, rcu);
return 0;
}
trace_block_bio_remap(bdev_get_queue(split->bi_bdev),
split, disk_devt(mddev->gendisk),
bio_sector);
+ mddev_check_writesame(mddev, split);
generic_make_request(split);
}
} while (split != bio);
{
struct rcu_head rcu;
sector_t array_sectors;
+ int raid_disks; /* a copy of mddev->raid_disks */
struct dev_info disks[0];
};
#endif
}
EXPORT_SYMBOL_GPL(bio_alloc_mddev);
-struct bio *bio_clone_mddev(struct bio *bio, gfp_t gfp_mask,
- struct mddev *mddev)
-{
- if (!mddev || !mddev->bio_set)
- return bio_clone(bio, gfp_mask);
-
- return bio_clone_bioset(bio, gfp_mask, mddev->bio_set);
-}
-EXPORT_SYMBOL_GPL(bio_clone_mddev);
-
/*
* We have a system wide 'event count' that is incremented
* on any 'interesting' event, and readers of /proc/mdstat
sysfs_notify_dirent_safe(rdev->sysfs_state);
}
- if (mddev->bio_set == NULL)
+ if (mddev->bio_set == NULL) {
mddev->bio_set = bioset_create(BIO_POOL_SIZE, 0);
+ if (!mddev->bio_set)
+ return -ENOMEM;
+ }
spin_lock(&pers_lock);
pers = find_pers(mddev->level, mddev->clevel);
for_each_mddev(mddev, tmp) {
export_array(mddev);
+ mddev->ctime = 0;
mddev->hold_active = 0;
+ /*
+ * for_each_mddev() will call mddev_put() at the end of each
+ * iteration. As the mddev is now fully clear, this will
+ * schedule the mddev for destruction by a workqueue, and the
+ * destroy_workqueue() below will wait for that to complete.
+ */
}
destroy_workqueue(md_misc_wq);
destroy_workqueue(md_wq);
extern void mddev_suspend(struct mddev *mddev);
extern void mddev_resume(struct mddev *mddev);
-extern struct bio *bio_clone_mddev(struct bio *bio, gfp_t gfp_mask,
- struct mddev *mddev);
extern struct bio *bio_alloc_mddev(gfp_t gfp_mask, int nr_iovecs,
struct mddev *mddev);
{
mddev->flags &= ~unsupported_flags;
}
+
+static inline void mddev_check_writesame(struct mddev *mddev, struct bio *bio)
+{
+ if (bio_op(bio) == REQ_OP_WRITE_SAME &&
+ !bdev_get_queue(bio->bi_bdev)->limits.max_write_same_sectors)
+ mddev->queue->limits.max_write_same_sectors = 0;
+}
#endif /* _MD_MD_H */
mp_bh->bio.bi_opf |= REQ_FAILFAST_TRANSPORT;
mp_bh->bio.bi_end_io = multipath_end_request;
mp_bh->bio.bi_private = mp_bh;
+ mddev_check_writesame(mddev, &mp_bh->bio);
generic_make_request(&mp_bh->bio);
return;
}
trace_block_bio_remap(bdev_get_queue(split->bi_bdev),
split, disk_devt(mddev->gendisk),
bio_sector);
+ mddev_check_writesame(mddev, split);
generic_make_request(split);
}
} while (split != bio);
*/
static int max_queued_requests = 1024;
-static void allow_barrier(struct r1conf *conf, sector_t start_next_window,
- sector_t bi_sector);
-static void lower_barrier(struct r1conf *conf);
+static void allow_barrier(struct r1conf *conf, sector_t sector_nr);
+static void lower_barrier(struct r1conf *conf, sector_t sector_nr);
#define raid1_log(md, fmt, args...) \
do { if ((md)->queue) blk_add_trace_msg((md)->queue, "raid1 " fmt, ##args); } while (0)
#define RESYNC_WINDOW_SECTORS (RESYNC_WINDOW >> 9)
#define CLUSTER_RESYNC_WINDOW (16 * RESYNC_WINDOW)
#define CLUSTER_RESYNC_WINDOW_SECTORS (CLUSTER_RESYNC_WINDOW >> 9)
-#define NEXT_NORMALIO_DISTANCE (3 * RESYNC_WINDOW_SECTORS)
static void * r1buf_pool_alloc(gfp_t gfp_flags, void *data)
{
static void put_buf(struct r1bio *r1_bio)
{
struct r1conf *conf = r1_bio->mddev->private;
+ sector_t sect = r1_bio->sector;
int i;
for (i = 0; i < conf->raid_disks * 2; i++) {
mempool_free(r1_bio, conf->r1buf_pool);
- lower_barrier(conf);
+ lower_barrier(conf, sect);
}
static void reschedule_retry(struct r1bio *r1_bio)
unsigned long flags;
struct mddev *mddev = r1_bio->mddev;
struct r1conf *conf = mddev->private;
+ int idx;
+ idx = sector_to_idx(r1_bio->sector);
spin_lock_irqsave(&conf->device_lock, flags);
list_add(&r1_bio->retry_list, &conf->retry_list);
- conf->nr_queued ++;
+ atomic_inc(&conf->nr_queued[idx]);
spin_unlock_irqrestore(&conf->device_lock, flags);
wake_up(&conf->wait_barrier);
struct bio *bio = r1_bio->master_bio;
int done;
struct r1conf *conf = r1_bio->mddev->private;
- sector_t start_next_window = r1_bio->start_next_window;
sector_t bi_sector = bio->bi_iter.bi_sector;
if (bio->bi_phys_segments) {
* Wake up any possible resync thread that waits for the device
* to go idle.
*/
- allow_barrier(conf, start_next_window, bi_sector);
+ allow_barrier(conf, bi_sector);
}
}
bio_put(to_put);
}
+static sector_t align_to_barrier_unit_end(sector_t start_sector,
+ sector_t sectors)
+{
+ sector_t len;
+
+ WARN_ON(sectors == 0);
+ /*
+ * len is the number of sectors from start_sector to end of the
+ * barrier unit which start_sector belongs to.
+ */
+ len = round_up(start_sector + 1, BARRIER_UNIT_SECTOR_SIZE) -
+ start_sector;
+
+ if (len > sectors)
+ len = sectors;
+
+ return len;
+}
+
/*
* This routine returns the disk from which the requested read should
* be done. There is a per-array 'next expected sequential IO' sector
*/
static void raise_barrier(struct r1conf *conf, sector_t sector_nr)
{
+ int idx = sector_to_idx(sector_nr);
+
spin_lock_irq(&conf->resync_lock);
/* Wait until no block IO is waiting */
- wait_event_lock_irq(conf->wait_barrier, !conf->nr_waiting,
+ wait_event_lock_irq(conf->wait_barrier,
+ !atomic_read(&conf->nr_waiting[idx]),
conf->resync_lock);
/* block any new IO from starting */
- conf->barrier++;
- conf->next_resync = sector_nr;
+ atomic_inc(&conf->barrier[idx]);
+ /*
+ * In raise_barrier() we firstly increase conf->barrier[idx] then
+ * check conf->nr_pending[idx]. In _wait_barrier() we firstly
+ * increase conf->nr_pending[idx] then check conf->barrier[idx].
+ * A memory barrier here to make sure conf->nr_pending[idx] won't
+ * be fetched before conf->barrier[idx] is increased. Otherwise
+ * there will be a race between raise_barrier() and _wait_barrier().
+ */
+ smp_mb__after_atomic();
/* For these conditions we must wait:
* A: while the array is in frozen state
- * B: while barrier >= RESYNC_DEPTH, meaning resync reach
- * the max count which allowed.
- * C: next_resync + RESYNC_SECTORS > start_next_window, meaning
- * next resync will reach to the window which normal bios are
- * handling.
- * D: while there are any active requests in the current window.
+ * B: while conf->nr_pending[idx] is not 0, meaning regular I/O
+ * existing in corresponding I/O barrier bucket.
+ * C: while conf->barrier[idx] >= RESYNC_DEPTH, meaning reaches
+ * max resync count which allowed on current I/O barrier bucket.
*/
wait_event_lock_irq(conf->wait_barrier,
!conf->array_frozen &&
- conf->barrier < RESYNC_DEPTH &&
- conf->current_window_requests == 0 &&
- (conf->start_next_window >=
- conf->next_resync + RESYNC_SECTORS),
+ !atomic_read(&conf->nr_pending[idx]) &&
+ atomic_read(&conf->barrier[idx]) < RESYNC_DEPTH,
conf->resync_lock);
- conf->nr_pending++;
+ atomic_inc(&conf->nr_pending[idx]);
spin_unlock_irq(&conf->resync_lock);
}
-static void lower_barrier(struct r1conf *conf)
+static void lower_barrier(struct r1conf *conf, sector_t sector_nr)
{
- unsigned long flags;
- BUG_ON(conf->barrier <= 0);
- spin_lock_irqsave(&conf->resync_lock, flags);
- conf->barrier--;
- conf->nr_pending--;
- spin_unlock_irqrestore(&conf->resync_lock, flags);
+ int idx = sector_to_idx(sector_nr);
+
+ BUG_ON(atomic_read(&conf->barrier[idx]) <= 0);
+
+ atomic_dec(&conf->barrier[idx]);
+ atomic_dec(&conf->nr_pending[idx]);
wake_up(&conf->wait_barrier);
}
-static bool need_to_wait_for_sync(struct r1conf *conf, struct bio *bio)
+static void _wait_barrier(struct r1conf *conf, int idx)
{
- bool wait = false;
+ /*
+ * We need to increase conf->nr_pending[idx] very early here,
+ * then raise_barrier() can be blocked when it waits for
+ * conf->nr_pending[idx] to be 0. Then we can avoid holding
+ * conf->resync_lock when there is no barrier raised in same
+ * barrier unit bucket. Also if the array is frozen, I/O
+ * should be blocked until array is unfrozen.
+ */
+ atomic_inc(&conf->nr_pending[idx]);
+ /*
+ * In _wait_barrier() we firstly increase conf->nr_pending[idx], then
+ * check conf->barrier[idx]. In raise_barrier() we firstly increase
+ * conf->barrier[idx], then check conf->nr_pending[idx]. A memory
+ * barrier is necessary here to make sure conf->barrier[idx] won't be
+ * fetched before conf->nr_pending[idx] is increased. Otherwise there
+ * will be a race between _wait_barrier() and raise_barrier().
+ */
+ smp_mb__after_atomic();
- if (conf->array_frozen || !bio)
- wait = true;
- else if (conf->barrier && bio_data_dir(bio) == WRITE) {
- if ((conf->mddev->curr_resync_completed
- >= bio_end_sector(bio)) ||
- (conf->start_next_window + NEXT_NORMALIO_DISTANCE
- <= bio->bi_iter.bi_sector))
- wait = false;
- else
- wait = true;
- }
+ /*
+ * Don't worry about checking two atomic_t variables at same time
+ * here. If during we check conf->barrier[idx], the array is
+ * frozen (conf->array_frozen is 1), and chonf->barrier[idx] is
+ * 0, it is safe to return and make the I/O continue. Because the
+ * array is frozen, all I/O returned here will eventually complete
+ * or be queued, no race will happen. See code comment in
+ * frozen_array().
+ */
+ if (!READ_ONCE(conf->array_frozen) &&
+ !atomic_read(&conf->barrier[idx]))
+ return;
- return wait;
+ /*
+ * After holding conf->resync_lock, conf->nr_pending[idx]
+ * should be decreased before waiting for barrier to drop.
+ * Otherwise, we may encounter a race condition because
+ * raise_barrer() might be waiting for conf->nr_pending[idx]
+ * to be 0 at same time.
+ */
+ spin_lock_irq(&conf->resync_lock);
+ atomic_inc(&conf->nr_waiting[idx]);
+ atomic_dec(&conf->nr_pending[idx]);
+ /*
+ * In case freeze_array() is waiting for
+ * get_unqueued_pending() == extra
+ */
+ wake_up(&conf->wait_barrier);
+ /* Wait for the barrier in same barrier unit bucket to drop. */
+ wait_event_lock_irq(conf->wait_barrier,
+ !conf->array_frozen &&
+ !atomic_read(&conf->barrier[idx]),
+ conf->resync_lock);
+ atomic_inc(&conf->nr_pending[idx]);
+ atomic_dec(&conf->nr_waiting[idx]);
+ spin_unlock_irq(&conf->resync_lock);
}
-static sector_t wait_barrier(struct r1conf *conf, struct bio *bio)
+static void wait_read_barrier(struct r1conf *conf, sector_t sector_nr)
{
- sector_t sector = 0;
+ int idx = sector_to_idx(sector_nr);
- spin_lock_irq(&conf->resync_lock);
- if (need_to_wait_for_sync(conf, bio)) {
- conf->nr_waiting++;
- /* Wait for the barrier to drop.
- * However if there are already pending
- * requests (preventing the barrier from
- * rising completely), and the
- * per-process bio queue isn't empty,
- * then don't wait, as we need to empty
- * that queue to allow conf->start_next_window
- * to increase.
- */
- raid1_log(conf->mddev, "wait barrier");
- wait_event_lock_irq(conf->wait_barrier,
- !conf->array_frozen &&
- (!conf->barrier ||
- ((conf->start_next_window <
- conf->next_resync + RESYNC_SECTORS) &&
- current->bio_list &&
- !bio_list_empty(current->bio_list))),
- conf->resync_lock);
- conf->nr_waiting--;
- }
-
- if (bio && bio_data_dir(bio) == WRITE) {
- if (bio->bi_iter.bi_sector >= conf->next_resync) {
- if (conf->start_next_window == MaxSector)
- conf->start_next_window =
- conf->next_resync +
- NEXT_NORMALIO_DISTANCE;
-
- if ((conf->start_next_window + NEXT_NORMALIO_DISTANCE)
- <= bio->bi_iter.bi_sector)
- conf->next_window_requests++;
- else
- conf->current_window_requests++;
- sector = conf->start_next_window;
- }
- }
+ /*
+ * Very similar to _wait_barrier(). The difference is, for read
+ * I/O we don't need wait for sync I/O, but if the whole array
+ * is frozen, the read I/O still has to wait until the array is
+ * unfrozen. Since there is no ordering requirement with
+ * conf->barrier[idx] here, memory barrier is unnecessary as well.
+ */
+ atomic_inc(&conf->nr_pending[idx]);
- conf->nr_pending++;
+ if (!READ_ONCE(conf->array_frozen))
+ return;
+
+ spin_lock_irq(&conf->resync_lock);
+ atomic_inc(&conf->nr_waiting[idx]);
+ atomic_dec(&conf->nr_pending[idx]);
+ /*
+ * In case freeze_array() is waiting for
+ * get_unqueued_pending() == extra
+ */
+ wake_up(&conf->wait_barrier);
+ /* Wait for array to be unfrozen */
+ wait_event_lock_irq(conf->wait_barrier,
+ !conf->array_frozen,
+ conf->resync_lock);
+ atomic_inc(&conf->nr_pending[idx]);
+ atomic_dec(&conf->nr_waiting[idx]);
spin_unlock_irq(&conf->resync_lock);
- return sector;
}
-static void allow_barrier(struct r1conf *conf, sector_t start_next_window,
- sector_t bi_sector)
+static void wait_barrier(struct r1conf *conf, sector_t sector_nr)
{
- unsigned long flags;
+ int idx = sector_to_idx(sector_nr);
- spin_lock_irqsave(&conf->resync_lock, flags);
- conf->nr_pending--;
- if (start_next_window) {
- if (start_next_window == conf->start_next_window) {
- if (conf->start_next_window + NEXT_NORMALIO_DISTANCE
- <= bi_sector)
- conf->next_window_requests--;
- else
- conf->current_window_requests--;
- } else
- conf->current_window_requests--;
-
- if (!conf->current_window_requests) {
- if (conf->next_window_requests) {
- conf->current_window_requests =
- conf->next_window_requests;
- conf->next_window_requests = 0;
- conf->start_next_window +=
- NEXT_NORMALIO_DISTANCE;
- } else
- conf->start_next_window = MaxSector;
- }
- }
- spin_unlock_irqrestore(&conf->resync_lock, flags);
+ _wait_barrier(conf, idx);
+}
+
+static void wait_all_barriers(struct r1conf *conf)
+{
+ int idx;
+
+ for (idx = 0; idx < BARRIER_BUCKETS_NR; idx++)
+ _wait_barrier(conf, idx);
+}
+
+static void _allow_barrier(struct r1conf *conf, int idx)
+{
+ atomic_dec(&conf->nr_pending[idx]);
wake_up(&conf->wait_barrier);
}
+static void allow_barrier(struct r1conf *conf, sector_t sector_nr)
+{
+ int idx = sector_to_idx(sector_nr);
+
+ _allow_barrier(conf, idx);
+}
+
+static void allow_all_barriers(struct r1conf *conf)
+{
+ int idx;
+
+ for (idx = 0; idx < BARRIER_BUCKETS_NR; idx++)
+ _allow_barrier(conf, idx);
+}
+
+/* conf->resync_lock should be held */
+static int get_unqueued_pending(struct r1conf *conf)
+{
+ int idx, ret;
+
+ for (ret = 0, idx = 0; idx < BARRIER_BUCKETS_NR; idx++)
+ ret += atomic_read(&conf->nr_pending[idx]) -
+ atomic_read(&conf->nr_queued[idx]);
+
+ return ret;
+}
+
static void freeze_array(struct r1conf *conf, int extra)
{
- /* stop syncio and normal IO and wait for everything to
+ /* Stop sync I/O and normal I/O and wait for everything to
* go quite.
- * We wait until nr_pending match nr_queued+extra
- * This is called in the context of one normal IO request
- * that has failed. Thus any sync request that might be pending
- * will be blocked by nr_pending, and we need to wait for
- * pending IO requests to complete or be queued for re-try.
- * Thus the number queued (nr_queued) plus this request (extra)
- * must match the number of pending IOs (nr_pending) before
- * we continue.
+ * This is called in two situations:
+ * 1) management command handlers (reshape, remove disk, quiesce).
+ * 2) one normal I/O request failed.
+
+ * After array_frozen is set to 1, new sync IO will be blocked at
+ * raise_barrier(), and new normal I/O will blocked at _wait_barrier()
+ * or wait_read_barrier(). The flying I/Os will either complete or be
+ * queued. When everything goes quite, there are only queued I/Os left.
+
+ * Every flying I/O contributes to a conf->nr_pending[idx], idx is the
+ * barrier bucket index which this I/O request hits. When all sync and
+ * normal I/O are queued, sum of all conf->nr_pending[] will match sum
+ * of all conf->nr_queued[]. But normal I/O failure is an exception,
+ * in handle_read_error(), we may call freeze_array() before trying to
+ * fix the read error. In this case, the error read I/O is not queued,
+ * so get_unqueued_pending() == 1.
+ *
+ * Therefore before this function returns, we need to wait until
+ * get_unqueued_pendings(conf) gets equal to extra. For
+ * normal I/O context, extra is 1, in rested situations extra is 0.
*/
spin_lock_irq(&conf->resync_lock);
conf->array_frozen = 1;
raid1_log(conf->mddev, "wait freeze");
- wait_event_lock_irq_cmd(conf->wait_barrier,
- conf->nr_pending == conf->nr_queued+extra,
- conf->resync_lock,
- flush_pending_writes(conf));
+ wait_event_lock_irq_cmd(
+ conf->wait_barrier,
+ get_unqueued_pending(conf) == extra,
+ conf->resync_lock,
+ flush_pending_writes(conf));
spin_unlock_irq(&conf->resync_lock);
}
static void unfreeze_array(struct r1conf *conf)
/* reverse the effect of the freeze */
spin_lock_irq(&conf->resync_lock);
conf->array_frozen = 0;
- wake_up(&conf->wait_barrier);
spin_unlock_irq(&conf->resync_lock);
+ wake_up(&conf->wait_barrier);
}
/* duplicate the data pages for behind I/O
kfree(plug);
}
-static void raid1_read_request(struct mddev *mddev, struct bio *bio,
- struct r1bio *r1_bio)
+static inline struct r1bio *
+alloc_r1bio(struct mddev *mddev, struct bio *bio, sector_t sectors_handled)
+{
+ struct r1conf *conf = mddev->private;
+ struct r1bio *r1_bio;
+
+ r1_bio = mempool_alloc(conf->r1bio_pool, GFP_NOIO);
+
+ r1_bio->master_bio = bio;
+ r1_bio->sectors = bio_sectors(bio) - sectors_handled;
+ r1_bio->state = 0;
+ r1_bio->mddev = mddev;
+ r1_bio->sector = bio->bi_iter.bi_sector + sectors_handled;
+
+ return r1_bio;
+}
+
+static void raid1_read_request(struct mddev *mddev, struct bio *bio)
{
struct r1conf *conf = mddev->private;
struct raid1_info *mirror;
+ struct r1bio *r1_bio;
struct bio *read_bio;
struct bitmap *bitmap = mddev->bitmap;
const int op = bio_op(bio);
int max_sectors;
int rdisk;
- wait_barrier(conf, bio);
+ /*
+ * Still need barrier for READ in case that whole
+ * array is frozen.
+ */
+ wait_read_barrier(conf, bio->bi_iter.bi_sector);
+
+ r1_bio = alloc_r1bio(mddev, bio, 0);
+ /*
+ * We might need to issue multiple reads to different
+ * devices if there are bad blocks around, so we keep
+ * track of the number of reads in bio->bi_phys_segments.
+ * If this is 0, there is only one r1_bio and no locking
+ * will be needed when requests complete. If it is
+ * non-zero, then it is the number of not-completed requests.
+ */
+ bio->bi_phys_segments = 0;
+ bio_clear_flag(bio, BIO_SEG_VALID);
+
+ /*
+ * make_request() can abort the operation when read-ahead is being
+ * used and no empty request is available.
+ */
read_again:
rdisk = read_balance(conf, r1_bio, &max_sectors);
atomic_read(&bitmap->behind_writes) == 0);
}
r1_bio->read_disk = rdisk;
- r1_bio->start_next_window = 0;
- read_bio = bio_clone_mddev(bio, GFP_NOIO, mddev);
+ read_bio = bio_clone_fast(bio, GFP_NOIO, mddev->bio_set);
bio_trim(read_bio, r1_bio->sector - bio->bi_iter.bi_sector,
max_sectors);
*/
reschedule_retry(r1_bio);
- r1_bio = mempool_alloc(conf->r1bio_pool, GFP_NOIO);
-
- r1_bio->master_bio = bio;
- r1_bio->sectors = bio_sectors(bio) - sectors_handled;
- r1_bio->state = 0;
- r1_bio->mddev = mddev;
- r1_bio->sector = bio->bi_iter.bi_sector + sectors_handled;
+ r1_bio = alloc_r1bio(mddev, bio, sectors_handled);
goto read_again;
} else
generic_make_request(read_bio);
}
-static void raid1_write_request(struct mddev *mddev, struct bio *bio,
- struct r1bio *r1_bio)
+static void raid1_write_request(struct mddev *mddev, struct bio *bio)
{
struct r1conf *conf = mddev->private;
+ struct r1bio *r1_bio;
int i, disks;
struct bitmap *bitmap = mddev->bitmap;
unsigned long flags;
int first_clone;
int sectors_handled;
int max_sectors;
- sector_t start_next_window;
/*
* Register the new request and wait if the reconstruction
}
finish_wait(&conf->wait_barrier, &w);
}
- start_next_window = wait_barrier(conf, bio);
+ wait_barrier(conf, bio->bi_iter.bi_sector);
+
+ r1_bio = alloc_r1bio(mddev, bio, 0);
+
+ /* We might need to issue multiple writes to different
+ * devices if there are bad blocks around, so we keep
+ * track of the number of writes in bio->bi_phys_segments.
+ * If this is 0, there is only one r1_bio and no locking
+ * will be needed when requests complete. If it is
+ * non-zero, then it is the number of not-completed requests.
+ */
+ bio->bi_phys_segments = 0;
+ bio_clear_flag(bio, BIO_SEG_VALID);
if (conf->pending_count >= max_queued_requests) {
md_wakeup_thread(mddev->thread);
disks = conf->raid_disks * 2;
retry_write:
- r1_bio->start_next_window = start_next_window;
blocked_rdev = NULL;
rcu_read_lock();
max_sectors = r1_bio->sectors;
if (unlikely(blocked_rdev)) {
/* Wait for this device to become unblocked */
int j;
- sector_t old = start_next_window;
for (j = 0; j < i; j++)
if (r1_bio->bios[j])
rdev_dec_pending(conf->mirrors[j].rdev, mddev);
r1_bio->state = 0;
- allow_barrier(conf, start_next_window, bio->bi_iter.bi_sector);
+ allow_barrier(conf, bio->bi_iter.bi_sector);
raid1_log(mddev, "wait rdev %d blocked", blocked_rdev->raid_disk);
md_wait_for_blocked_rdev(blocked_rdev, mddev);
- start_next_window = wait_barrier(conf, bio);
- /*
- * We must make sure the multi r1bios of bio have
- * the same value of bi_phys_segments
- */
- if (bio->bi_phys_segments && old &&
- old != start_next_window)
- /* Wait for the former r1bio(s) to complete */
- wait_event(conf->wait_barrier,
- bio->bi_phys_segments == 1);
+ wait_barrier(conf, bio->bi_iter.bi_sector);
goto retry_write;
}
first_clone = 1;
for (i = 0; i < disks; i++) {
- struct bio *mbio;
+ struct bio *mbio = NULL;
+ sector_t offset;
if (!r1_bio->bios[i])
continue;
- mbio = bio_clone_mddev(bio, GFP_NOIO, mddev);
- bio_trim(mbio, r1_bio->sector - bio->bi_iter.bi_sector,
- max_sectors);
+ offset = r1_bio->sector - bio->bi_iter.bi_sector;
if (first_clone) {
/* do behind I/O ?
if (bitmap &&
(atomic_read(&bitmap->behind_writes)
< mddev->bitmap_info.max_write_behind) &&
- !waitqueue_active(&bitmap->behind_wait))
+ !waitqueue_active(&bitmap->behind_wait)) {
+ mbio = bio_clone_bioset_partial(bio, GFP_NOIO,
+ mddev->bio_set,
+ offset << 9,
+ max_sectors << 9);
alloc_behind_pages(mbio, r1_bio);
+ }
bitmap_startwrite(bitmap, r1_bio->sector,
r1_bio->sectors,
&r1_bio->state));
first_clone = 0;
}
+
+ if (!mbio) {
+ if (r1_bio->behind_bvecs)
+ mbio = bio_clone_bioset_partial(bio, GFP_NOIO,
+ mddev->bio_set,
+ offset << 9,
+ max_sectors << 9);
+ else {
+ mbio = bio_clone_fast(bio, GFP_NOIO, mddev->bio_set);
+ bio_trim(mbio, offset, max_sectors);
+ }
+ }
+
if (r1_bio->behind_bvecs) {
struct bio_vec *bvec;
int j;
conf->mirrors[i].rdev->data_offset);
mbio->bi_bdev = conf->mirrors[i].rdev->bdev;
mbio->bi_end_io = raid1_end_write_request;
- mbio->bi_opf = bio_op(bio) |
- (bio->bi_opf & (REQ_SYNC | REQ_PREFLUSH | REQ_FUA));
+ mbio->bi_opf = bio_op(bio) | (bio->bi_opf & (REQ_SYNC | REQ_FUA));
if (test_bit(FailFast, &conf->mirrors[i].rdev->flags) &&
!test_bit(WriteMostly, &conf->mirrors[i].rdev->flags) &&
conf->raid_disks - mddev->degraded > 1)
/* We need another r1_bio. It has already been counted
* in bio->bi_phys_segments
*/
- r1_bio = mempool_alloc(conf->r1bio_pool, GFP_NOIO);
- r1_bio->master_bio = bio;
- r1_bio->sectors = bio_sectors(bio) - sectors_handled;
- r1_bio->state = 0;
- r1_bio->mddev = mddev;
- r1_bio->sector = bio->bi_iter.bi_sector + sectors_handled;
+ r1_bio = alloc_r1bio(mddev, bio, sectors_handled);
goto retry_write;
}
static void raid1_make_request(struct mddev *mddev, struct bio *bio)
{
- struct r1conf *conf = mddev->private;
- struct r1bio *r1_bio;
+ struct bio *split;
+ sector_t sectors;
- /*
- * make_request() can abort the operation when read-ahead is being
- * used and no empty request is available.
- *
- */
- r1_bio = mempool_alloc(conf->r1bio_pool, GFP_NOIO);
-
- r1_bio->master_bio = bio;
- r1_bio->sectors = bio_sectors(bio);
- r1_bio->state = 0;
- r1_bio->mddev = mddev;
- r1_bio->sector = bio->bi_iter.bi_sector;
+ if (unlikely(bio->bi_opf & REQ_PREFLUSH)) {
+ md_flush_request(mddev, bio);
+ return;
+ }
- /*
- * We might need to issue multiple reads to different devices if there
- * are bad blocks around, so we keep track of the number of reads in
- * bio->bi_phys_segments. If this is 0, there is only one r1_bio and
- * no locking will be needed when requests complete. If it is
- * non-zero, then it is the number of not-completed requests.
- */
- bio->bi_phys_segments = 0;
- bio_clear_flag(bio, BIO_SEG_VALID);
+ /* if bio exceeds barrier unit boundary, split it */
+ do {
+ sectors = align_to_barrier_unit_end(
+ bio->bi_iter.bi_sector, bio_sectors(bio));
+ if (sectors < bio_sectors(bio)) {
+ split = bio_split(bio, sectors, GFP_NOIO, fs_bio_set);
+ bio_chain(split, bio);
+ } else {
+ split = bio;
+ }
- if (bio_data_dir(bio) == READ)
- raid1_read_request(mddev, bio, r1_bio);
- else
- raid1_write_request(mddev, bio, r1_bio);
+ if (bio_data_dir(split) == READ)
+ raid1_read_request(mddev, split);
+ else
+ raid1_write_request(mddev, split);
+ } while (split != bio);
}
static void raid1_status(struct seq_file *seq, struct mddev *mddev)
static void close_sync(struct r1conf *conf)
{
- wait_barrier(conf, NULL);
- allow_barrier(conf, 0, 0);
+ wait_all_barriers(conf);
+ allow_all_barriers(conf);
mempool_destroy(conf->r1buf_pool);
conf->r1buf_pool = NULL;
-
- spin_lock_irq(&conf->resync_lock);
- conf->next_resync = MaxSector - 2 * NEXT_NORMALIO_DISTANCE;
- conf->start_next_window = MaxSector;
- conf->current_window_requests +=
- conf->next_window_requests;
- conf->next_window_requests = 0;
- spin_unlock_irq(&conf->resync_lock);
}
static int raid1_spare_active(struct mddev *mddev)
wbio->bi_vcnt = vcnt;
} else {
- wbio = bio_clone_mddev(r1_bio->master_bio, GFP_NOIO, mddev);
+ wbio = bio_clone_fast(r1_bio->master_bio, GFP_NOIO,
+ mddev->bio_set);
}
bio_set_op_attrs(wbio, REQ_OP_WRITE, 0);
static void handle_write_finished(struct r1conf *conf, struct r1bio *r1_bio)
{
- int m;
+ int m, idx;
bool fail = false;
+
for (m = 0; m < conf->raid_disks * 2 ; m++)
if (r1_bio->bios[m] == IO_MADE_GOOD) {
struct md_rdev *rdev = conf->mirrors[m].rdev;
if (fail) {
spin_lock_irq(&conf->device_lock);
list_add(&r1_bio->retry_list, &conf->bio_end_io_list);
- conf->nr_queued++;
+ idx = sector_to_idx(r1_bio->sector);
+ atomic_inc(&conf->nr_queued[idx]);
spin_unlock_irq(&conf->device_lock);
+ /*
+ * In case freeze_array() is waiting for condition
+ * get_unqueued_pending() == extra to be true.
+ */
+ wake_up(&conf->wait_barrier);
md_wakeup_thread(conf->mddev->thread);
} else {
if (test_bit(R1BIO_WriteError, &r1_bio->state))
const unsigned long do_sync
= r1_bio->master_bio->bi_opf & REQ_SYNC;
r1_bio->read_disk = disk;
- bio = bio_clone_mddev(r1_bio->master_bio, GFP_NOIO, mddev);
+ bio = bio_clone_fast(r1_bio->master_bio, GFP_NOIO,
+ mddev->bio_set);
bio_trim(bio, r1_bio->sector - bio->bi_iter.bi_sector,
max_sectors);
r1_bio->bios[r1_bio->read_disk] = bio;
generic_make_request(bio);
bio = NULL;
- r1_bio = mempool_alloc(conf->r1bio_pool, GFP_NOIO);
-
- r1_bio->master_bio = mbio;
- r1_bio->sectors = bio_sectors(mbio) - sectors_handled;
- r1_bio->state = 0;
+ r1_bio = alloc_r1bio(mddev, mbio, sectors_handled);
set_bit(R1BIO_ReadError, &r1_bio->state);
- r1_bio->mddev = mddev;
- r1_bio->sector = mbio->bi_iter.bi_sector +
- sectors_handled;
goto read_more;
} else {
struct r1conf *conf = mddev->private;
struct list_head *head = &conf->retry_list;
struct blk_plug plug;
+ int idx;
md_check_recovery(mddev);
!test_bit(MD_SB_CHANGE_PENDING, &mddev->sb_flags)) {
LIST_HEAD(tmp);
spin_lock_irqsave(&conf->device_lock, flags);
- if (!test_bit(MD_SB_CHANGE_PENDING, &mddev->sb_flags)) {
- while (!list_empty(&conf->bio_end_io_list)) {
- list_move(conf->bio_end_io_list.prev, &tmp);
- conf->nr_queued--;
- }
- }
+ if (!test_bit(MD_SB_CHANGE_PENDING, &mddev->sb_flags))
+ list_splice_init(&conf->bio_end_io_list, &tmp);
spin_unlock_irqrestore(&conf->device_lock, flags);
while (!list_empty(&tmp)) {
r1_bio = list_first_entry(&tmp, struct r1bio,
retry_list);
list_del(&r1_bio->retry_list);
+ idx = sector_to_idx(r1_bio->sector);
+ atomic_dec(&conf->nr_queued[idx]);
if (mddev->degraded)
set_bit(R1BIO_Degraded, &r1_bio->state);
if (test_bit(R1BIO_WriteError, &r1_bio->state))
}
r1_bio = list_entry(head->prev, struct r1bio, retry_list);
list_del(head->prev);
- conf->nr_queued--;
+ idx = sector_to_idx(r1_bio->sector);
+ atomic_dec(&conf->nr_queued[idx]);
spin_unlock_irqrestore(&conf->device_lock, flags);
mddev = r1_bio->mddev;
conf->poolinfo);
if (!conf->r1buf_pool)
return -ENOMEM;
- conf->next_resync = 0;
return 0;
}
int still_degraded = 0;
int good_sectors = RESYNC_SECTORS;
int min_bad = 0; /* number of sectors that are bad in all devices */
+ int idx = sector_to_idx(sector_nr);
if (!conf->r1buf_pool)
if (init_resync(conf))
* If there is non-resync activity waiting for a turn, then let it
* though before starting on this new sync request.
*/
- if (conf->nr_waiting)
+ if (atomic_read(&conf->nr_waiting[idx]))
schedule_timeout_uninterruptible(1);
/* we are incrementing sector_nr below. To be safe, we check against
r1_bio->sector = sector_nr;
r1_bio->state = 0;
set_bit(R1BIO_IsSync, &r1_bio->state);
+ /* make sure good_sectors won't go across barrier unit boundary */
+ good_sectors = align_to_barrier_unit_end(sector_nr, good_sectors);
for (i = 0; i < conf->raid_disks * 2; i++) {
struct md_rdev *rdev;
if (!conf)
goto abort;
+ conf->nr_pending = kcalloc(BARRIER_BUCKETS_NR,
+ sizeof(atomic_t), GFP_KERNEL);
+ if (!conf->nr_pending)
+ goto abort;
+
+ conf->nr_waiting = kcalloc(BARRIER_BUCKETS_NR,
+ sizeof(atomic_t), GFP_KERNEL);
+ if (!conf->nr_waiting)
+ goto abort;
+
+ conf->nr_queued = kcalloc(BARRIER_BUCKETS_NR,
+ sizeof(atomic_t), GFP_KERNEL);
+ if (!conf->nr_queued)
+ goto abort;
+
+ conf->barrier = kcalloc(BARRIER_BUCKETS_NR,
+ sizeof(atomic_t), GFP_KERNEL);
+ if (!conf->barrier)
+ goto abort;
+
conf->mirrors = kzalloc(sizeof(struct raid1_info)
* mddev->raid_disks * 2,
GFP_KERNEL);
conf->pending_count = 0;
conf->recovery_disabled = mddev->recovery_disabled - 1;
- conf->start_next_window = MaxSector;
- conf->current_window_requests = conf->next_window_requests = 0;
-
err = -EIO;
for (i = 0; i < conf->raid_disks * 2; i++) {
kfree(conf->mirrors);
safe_put_page(conf->tmppage);
kfree(conf->poolinfo);
+ kfree(conf->nr_pending);
+ kfree(conf->nr_waiting);
+ kfree(conf->nr_queued);
+ kfree(conf->barrier);
kfree(conf);
}
return ERR_PTR(err);
kfree(conf->mirrors);
safe_put_page(conf->tmppage);
kfree(conf->poolinfo);
+ kfree(conf->nr_pending);
+ kfree(conf->nr_waiting);
+ kfree(conf->nr_queued);
+ kfree(conf->barrier);
kfree(conf);
}
#ifndef _RAID1_H
#define _RAID1_H
+/*
+ * each barrier unit size is 64MB fow now
+ * note: it must be larger than RESYNC_DEPTH
+ */
+#define BARRIER_UNIT_SECTOR_BITS 17
+#define BARRIER_UNIT_SECTOR_SIZE (1<<17)
+/*
+ * In struct r1conf, the following members are related to I/O barrier
+ * buckets,
+ * atomic_t *nr_pending;
+ * atomic_t *nr_waiting;
+ * atomic_t *nr_queued;
+ * atomic_t *barrier;
+ * Each of them points to array of atomic_t variables, each array is
+ * designed to have BARRIER_BUCKETS_NR elements and occupy a single
+ * memory page. The data width of atomic_t variables is 4 bytes, equal
+ * to 1<<(ilog2(sizeof(atomic_t))), BARRIER_BUCKETS_NR_BITS is defined
+ * as (PAGE_SHIFT - ilog2(sizeof(int))) to make sure an array of
+ * atomic_t variables with BARRIER_BUCKETS_NR elements just exactly
+ * occupies a single memory page.
+ */
+#define BARRIER_BUCKETS_NR_BITS (PAGE_SHIFT - ilog2(sizeof(atomic_t)))
+#define BARRIER_BUCKETS_NR (1<<BARRIER_BUCKETS_NR_BITS)
+
struct raid1_info {
struct md_rdev *rdev;
sector_t head_position;
*/
int raid_disks;
- /* During resync, read_balancing is only allowed on the part
- * of the array that has been resynced. 'next_resync' tells us
- * where that is.
- */
- sector_t next_resync;
-
- /* When raid1 starts resync, we divide array into four partitions
- * |---------|--------------|---------------------|-------------|
- * next_resync start_next_window end_window
- * start_next_window = next_resync + NEXT_NORMALIO_DISTANCE
- * end_window = start_next_window + NEXT_NORMALIO_DISTANCE
- * current_window_requests means the count of normalIO between
- * start_next_window and end_window.
- * next_window_requests means the count of normalIO after end_window.
- * */
- sector_t start_next_window;
- int current_window_requests;
- int next_window_requests;
-
spinlock_t device_lock;
/* list of 'struct r1bio' that need to be processed by raid1d,
*/
wait_queue_head_t wait_barrier;
spinlock_t resync_lock;
- int nr_pending;
- int nr_waiting;
- int nr_queued;
- int barrier;
+ atomic_t *nr_pending;
+ atomic_t *nr_waiting;
+ atomic_t *nr_queued;
+ atomic_t *barrier;
int array_frozen;
/* Set to 1 if a full sync is needed, (fresh device added).
* in this BehindIO request
*/
sector_t sector;
- sector_t start_next_window;
int sectors;
unsigned long state;
struct mddev *mddev;
R1BIO_WriteError,
R1BIO_FailFast,
};
+
+static inline int sector_to_idx(sector_t sector)
+{
+ return hash_long(sector >> BARRIER_UNIT_SECTOR_BITS,
+ BARRIER_BUCKETS_NR_BITS);
+}
#endif
}
slot = r10_bio->read_slot;
- read_bio = bio_clone_mddev(bio, GFP_NOIO, mddev);
+ read_bio = bio_clone_fast(bio, GFP_NOIO, mddev->bio_set);
bio_trim(read_bio, r10_bio->sector - bio->bi_iter.bi_sector,
max_sectors);
int d = r10_bio->devs[i].devnum;
if (r10_bio->devs[i].bio) {
struct md_rdev *rdev = conf->mirrors[d].rdev;
- mbio = bio_clone_mddev(bio, GFP_NOIO, mddev);
+ mbio = bio_clone_fast(bio, GFP_NOIO, mddev->bio_set);
bio_trim(mbio, r10_bio->sector - bio->bi_iter.bi_sector,
max_sectors);
r10_bio->devs[i].bio = mbio;
smp_mb();
rdev = conf->mirrors[d].rdev;
}
- mbio = bio_clone_mddev(bio, GFP_NOIO, mddev);
+ mbio = bio_clone_fast(bio, GFP_NOIO, mddev->bio_set);
bio_trim(mbio, r10_bio->sector - bio->bi_iter.bi_sector,
max_sectors);
r10_bio->devs[i].repl_bio = mbio;
if (sectors > sect_to_write)
sectors = sect_to_write;
/* Write at 'sector' for 'sectors' */
- wbio = bio_clone_mddev(bio, GFP_NOIO, mddev);
+ wbio = bio_clone_fast(bio, GFP_NOIO, mddev->bio_set);
bio_trim(wbio, sector - bio->bi_iter.bi_sector, sectors);
wsector = r10_bio->devs[i].addr + (sector - r10_bio->sector);
wbio->bi_iter.bi_sector = wsector +
mdname(mddev),
bdevname(rdev->bdev, b),
(unsigned long long)r10_bio->sector);
- bio = bio_clone_mddev(r10_bio->master_bio,
- GFP_NOIO, mddev);
+ bio = bio_clone_fast(r10_bio->master_bio, GFP_NOIO, mddev->bio_set);
bio_trim(bio, r10_bio->sector - bio->bi_iter.bi_sector, max_sectors);
r10_bio->devs[slot].bio = bio;
r10_bio->devs[slot].rdev = rdev;
#include <linux/crc32c.h>
#include <linux/random.h>
#include <linux/kthread.h>
+#include <linux/types.h>
#include "md.h"
#include "raid5.h"
#include "bitmap.h"
struct work_struct deferred_io_work;
/* to disable write back during in degraded mode */
struct work_struct disable_writeback_work;
+
+ /* to for chunk_aligned_read in writeback mode, details below */
+ spinlock_t tree_lock;
+ struct radix_tree_root big_stripe_tree;
};
+/*
+ * Enable chunk_aligned_read() with write back cache.
+ *
+ * Each chunk may contain more than one stripe (for example, a 256kB
+ * chunk contains 64 4kB-page, so this chunk contain 64 stripes). For
+ * chunk_aligned_read, these stripes are grouped into one "big_stripe".
+ * For each big_stripe, we count how many stripes of this big_stripe
+ * are in the write back cache. These data are tracked in a radix tree
+ * (big_stripe_tree). We use radix_tree item pointer as the counter.
+ * r5c_tree_index() is used to calculate keys for the radix tree.
+ *
+ * chunk_aligned_read() calls r5c_big_stripe_cached() to look up
+ * big_stripe of each chunk in the tree. If this big_stripe is in the
+ * tree, chunk_aligned_read() aborts. This look up is protected by
+ * rcu_read_lock().
+ *
+ * It is necessary to remember whether a stripe is counted in
+ * big_stripe_tree. Instead of adding new flag, we reuses existing flags:
+ * STRIPE_R5C_PARTIAL_STRIPE and STRIPE_R5C_FULL_STRIPE. If either of these
+ * two flags are set, the stripe is counted in big_stripe_tree. This
+ * requires moving set_bit(STRIPE_R5C_PARTIAL_STRIPE) to
+ * r5c_try_caching_write(); and moving clear_bit of
+ * STRIPE_R5C_PARTIAL_STRIPE and STRIPE_R5C_FULL_STRIPE to
+ * r5c_finish_stripe_write_out().
+ */
+
+/*
+ * radix tree requests lowest 2 bits of data pointer to be 2b'00.
+ * So it is necessary to left shift the counter by 2 bits before using it
+ * as data pointer of the tree.
+ */
+#define R5C_RADIX_COUNT_SHIFT 2
+
+/*
+ * calculate key for big_stripe_tree
+ *
+ * sect: align_bi->bi_iter.bi_sector or sh->sector
+ */
+static inline sector_t r5c_tree_index(struct r5conf *conf,
+ sector_t sect)
+{
+ sector_t offset;
+
+ offset = sector_div(sect, conf->chunk_sectors);
+ return sect;
+}
+
/*
* an IO range starts from a meta data block and end at the next meta data
* block. The io unit's the meta data block tracks data/parity followed it. io
/*
* Total log space (in sectors) needed to flush all data in cache
*
- * Currently, writing-out phase automatically includes all pending writes
- * to the same sector. So the reclaim of each stripe takes up to
- * (conf->raid_disks + 1) pages of log space.
+ * To avoid deadlock due to log space, it is necessary to reserve log
+ * space to flush critical stripes (stripes that occupying log space near
+ * last_checkpoint). This function helps check how much log space is
+ * required to flush all cached stripes.
*
- * To totally avoid deadlock due to log space, the code reserves
- * (conf->raid_disks + 1) pages for each stripe in cache, which is not
- * necessary in most cases.
+ * To reduce log space requirements, two mechanisms are used to give cache
+ * flush higher priorities:
+ * 1. In handle_stripe_dirtying() and schedule_reconstruction(),
+ * stripes ALREADY in journal can be flushed w/o pending writes;
+ * 2. In r5l_write_stripe() and r5c_cache_data(), stripes NOT in journal
+ * can be delayed (r5l_add_no_space_stripe).
*
- * To improve this, we will need writing-out phase to be able to NOT include
- * pending writes, which will reduce the requirement to
- * (conf->max_degraded + 1) pages per stripe in cache.
+ * In cache flush, the stripe goes through 1 and then 2. For a stripe that
+ * already passed 1, flushing it requires at most (conf->max_degraded + 1)
+ * pages of journal space. For stripes that has not passed 1, flushing it
+ * requires (conf->raid_disks + 1) pages of journal space. There are at
+ * most (conf->group_cnt + 1) stripe that passed 1. So total journal space
+ * required to flush all cached stripes (in pages) is:
+ *
+ * (stripe_in_journal_count - group_cnt - 1) * (max_degraded + 1) +
+ * (group_cnt + 1) * (raid_disks + 1)
+ * or
+ * (stripe_in_journal_count) * (max_degraded + 1) +
+ * (group_cnt + 1) * (raid_disks - max_degraded)
*/
static sector_t r5c_log_required_to_flush_cache(struct r5conf *conf)
{
if (!r5c_is_writeback(log))
return 0;
- return BLOCK_SECTORS * (conf->raid_disks + 1) *
- atomic_read(&log->stripe_in_journal_count);
+ return BLOCK_SECTORS *
+ ((conf->max_degraded + 1) * atomic_read(&log->stripe_in_journal_count) +
+ (conf->raid_disks - conf->max_degraded) * (conf->group_cnt + 1));
}
/*
if (!test_and_set_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
atomic_inc(&conf->preread_active_stripes);
-
- if (test_and_clear_bit(STRIPE_R5C_PARTIAL_STRIPE, &sh->state)) {
- BUG_ON(atomic_read(&conf->r5c_cached_partial_stripes) == 0);
- atomic_dec(&conf->r5c_cached_partial_stripes);
- }
-
- if (test_and_clear_bit(STRIPE_R5C_FULL_STRIPE, &sh->state)) {
- BUG_ON(atomic_read(&conf->r5c_cached_full_stripes) == 0);
- atomic_dec(&conf->r5c_cached_full_stripes);
- }
}
static void r5c_handle_data_cached(struct stripe_head *sh)
atomic_inc(&conf->active_stripes);
r5c_make_stripe_write_out(sh);
+ if (test_bit(STRIPE_R5C_PARTIAL_STRIPE, &sh->state))
+ atomic_inc(&conf->r5c_flushing_partial_stripes);
+ else
+ atomic_inc(&conf->r5c_flushing_full_stripes);
raid5_release_stripe(sh);
}
unsigned long flags;
int total_cached;
int stripes_to_flush;
+ int flushing_partial, flushing_full;
if (!r5c_is_writeback(log))
return;
+ flushing_partial = atomic_read(&conf->r5c_flushing_partial_stripes);
+ flushing_full = atomic_read(&conf->r5c_flushing_full_stripes);
total_cached = atomic_read(&conf->r5c_cached_partial_stripes) +
- atomic_read(&conf->r5c_cached_full_stripes);
+ atomic_read(&conf->r5c_cached_full_stripes) -
+ flushing_full - flushing_partial;
if (total_cached > conf->min_nr_stripes * 3 / 4 ||
atomic_read(&conf->empty_inactive_list_nr) > 0)
*/
stripes_to_flush = R5C_RECLAIM_STRIPE_GROUP;
else if (total_cached > conf->min_nr_stripes * 1 / 2 ||
- atomic_read(&conf->r5c_cached_full_stripes) >
+ atomic_read(&conf->r5c_cached_full_stripes) - flushing_full >
R5C_FULL_STRIPE_FLUSH_BATCH)
/*
* if stripe cache pressure moderate, or if there is many full
!test_bit(STRIPE_HANDLE, &sh->state) &&
atomic_read(&sh->count) == 0) {
r5c_flush_stripe(conf, sh);
+ if (count++ >= R5C_RECLAIM_STRIPE_GROUP)
+ break;
}
- if (count++ >= R5C_RECLAIM_STRIPE_GROUP)
- break;
}
spin_unlock(&conf->device_lock);
spin_unlock_irqrestore(&log->stripe_in_journal_lock, flags);
int i;
struct r5dev *dev;
int to_cache = 0;
+ void **pslot;
+ sector_t tree_index;
+ int ret;
+ uintptr_t refcount;
BUG_ON(!r5c_is_writeback(log));
}
}
+ /* if the stripe is not counted in big_stripe_tree, add it now */
+ if (!test_bit(STRIPE_R5C_PARTIAL_STRIPE, &sh->state) &&
+ !test_bit(STRIPE_R5C_FULL_STRIPE, &sh->state)) {
+ tree_index = r5c_tree_index(conf, sh->sector);
+ spin_lock(&log->tree_lock);
+ pslot = radix_tree_lookup_slot(&log->big_stripe_tree,
+ tree_index);
+ if (pslot) {
+ refcount = (uintptr_t)radix_tree_deref_slot_protected(
+ pslot, &log->tree_lock) >>
+ R5C_RADIX_COUNT_SHIFT;
+ radix_tree_replace_slot(
+ &log->big_stripe_tree, pslot,
+ (void *)((refcount + 1) << R5C_RADIX_COUNT_SHIFT));
+ } else {
+ /*
+ * this radix_tree_insert can fail safely, so no
+ * need to call radix_tree_preload()
+ */
+ ret = radix_tree_insert(
+ &log->big_stripe_tree, tree_index,
+ (void *)(1 << R5C_RADIX_COUNT_SHIFT));
+ if (ret) {
+ spin_unlock(&log->tree_lock);
+ r5c_make_stripe_write_out(sh);
+ return -EAGAIN;
+ }
+ }
+ spin_unlock(&log->tree_lock);
+
+ /*
+ * set STRIPE_R5C_PARTIAL_STRIPE, this shows the stripe is
+ * counted in the radix tree
+ */
+ set_bit(STRIPE_R5C_PARTIAL_STRIPE, &sh->state);
+ atomic_inc(&conf->r5c_cached_partial_stripes);
+ }
+
for (i = disks; i--; ) {
dev = &sh->dev[i];
if (dev->towrite) {
struct stripe_head *sh,
struct stripe_head_state *s)
{
+ struct r5l_log *log = conf->log;
int i;
int do_wakeup = 0;
+ sector_t tree_index;
+ void **pslot;
+ uintptr_t refcount;
- if (!conf->log ||
- !test_bit(R5_InJournal, &sh->dev[sh->pd_idx].flags))
+ if (!log || !test_bit(R5_InJournal, &sh->dev[sh->pd_idx].flags))
return;
WARN_ON(test_bit(STRIPE_R5C_CACHING, &sh->state));
clear_bit(R5_InJournal, &sh->dev[sh->pd_idx].flags);
- if (conf->log->r5c_journal_mode == R5C_JOURNAL_MODE_WRITE_THROUGH)
+ if (log->r5c_journal_mode == R5C_JOURNAL_MODE_WRITE_THROUGH)
return;
for (i = sh->disks; i--; ) {
if (do_wakeup)
wake_up(&conf->wait_for_overlap);
- spin_lock_irq(&conf->log->stripe_in_journal_lock);
+ spin_lock_irq(&log->stripe_in_journal_lock);
list_del_init(&sh->r5c);
- spin_unlock_irq(&conf->log->stripe_in_journal_lock);
+ spin_unlock_irq(&log->stripe_in_journal_lock);
sh->log_start = MaxSector;
- atomic_dec(&conf->log->stripe_in_journal_count);
- r5c_update_log_state(conf->log);
+
+ atomic_dec(&log->stripe_in_journal_count);
+ r5c_update_log_state(log);
+
+ /* stop counting this stripe in big_stripe_tree */
+ if (test_bit(STRIPE_R5C_PARTIAL_STRIPE, &sh->state) ||
+ test_bit(STRIPE_R5C_FULL_STRIPE, &sh->state)) {
+ tree_index = r5c_tree_index(conf, sh->sector);
+ spin_lock(&log->tree_lock);
+ pslot = radix_tree_lookup_slot(&log->big_stripe_tree,
+ tree_index);
+ BUG_ON(pslot == NULL);
+ refcount = (uintptr_t)radix_tree_deref_slot_protected(
+ pslot, &log->tree_lock) >>
+ R5C_RADIX_COUNT_SHIFT;
+ if (refcount == 1)
+ radix_tree_delete(&log->big_stripe_tree, tree_index);
+ else
+ radix_tree_replace_slot(
+ &log->big_stripe_tree, pslot,
+ (void *)((refcount - 1) << R5C_RADIX_COUNT_SHIFT));
+ spin_unlock(&log->tree_lock);
+ }
+
+ if (test_and_clear_bit(STRIPE_R5C_PARTIAL_STRIPE, &sh->state)) {
+ BUG_ON(atomic_read(&conf->r5c_cached_partial_stripes) == 0);
+ atomic_dec(&conf->r5c_flushing_partial_stripes);
+ atomic_dec(&conf->r5c_cached_partial_stripes);
+ }
+
+ if (test_and_clear_bit(STRIPE_R5C_FULL_STRIPE, &sh->state)) {
+ BUG_ON(atomic_read(&conf->r5c_cached_full_stripes) == 0);
+ atomic_dec(&conf->r5c_flushing_full_stripes);
+ atomic_dec(&conf->r5c_cached_full_stripes);
+ }
}
int
return 0;
}
+/* check whether this big stripe is in write back cache. */
+bool r5c_big_stripe_cached(struct r5conf *conf, sector_t sect)
+{
+ struct r5l_log *log = conf->log;
+ sector_t tree_index;
+ void *slot;
+
+ if (!log)
+ return false;
+
+ WARN_ON_ONCE(!rcu_read_lock_held());
+ tree_index = r5c_tree_index(conf, sect);
+ slot = radix_tree_lookup(&log->big_stripe_tree, tree_index);
+ return slot != NULL;
+}
+
static int r5l_load_log(struct r5l_log *log)
{
struct md_rdev *rdev = log->rdev;
if (!log->meta_pool)
goto out_mempool;
+ spin_lock_init(&log->tree_lock);
+ INIT_RADIX_TREE(&log->big_stripe_tree, GFP_NOWAIT | __GFP_NOWARN);
+
log->reclaim_thread = md_register_thread(r5l_reclaim_thread,
log->rdev->mddev, "reclaim");
if (!log->reclaim_thread)
atomic_dec(&conf->r5c_cached_partial_stripes);
list_add_tail(&sh->lru, &conf->r5c_full_stripe_list);
r5c_check_cached_full_stripe(conf);
- } else {
- /* partial stripe */
- if (!test_and_set_bit(STRIPE_R5C_PARTIAL_STRIPE,
- &sh->state))
- atomic_inc(&conf->r5c_cached_partial_stripes);
+ } 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 int release_stripe_list(struct r5conf *conf,
struct list_head *temp_inactive_list)
{
- struct stripe_head *sh;
+ struct stripe_head *sh, *t;
int count = 0;
struct llist_node *head;
head = llist_del_all(&conf->released_stripes);
head = llist_reverse_order(head);
- while (head) {
+ llist_for_each_entry_safe(sh, t, head, release_list) {
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);
return 1;
}
+static void flush_deferred_bios(struct r5conf *conf)
+{
+ struct bio_list tmp;
+ struct bio *bio;
+
+ if (!conf->batch_bio_dispatch || !conf->group_cnt)
+ return;
+
+ bio_list_init(&tmp);
+ spin_lock(&conf->pending_bios_lock);
+ bio_list_merge(&tmp, &conf->pending_bios);
+ bio_list_init(&conf->pending_bios);
+ spin_unlock(&conf->pending_bios_lock);
+
+ while ((bio = bio_list_pop(&tmp)))
+ generic_make_request(bio);
+}
+
+static void defer_bio_issue(struct r5conf *conf, struct bio *bio)
+{
+ /*
+ * change group_cnt will drain all bios, so this is safe
+ *
+ * A read generally means a read-modify-write, which usually means a
+ * randwrite, so we don't delay it
+ */
+ if (!conf->batch_bio_dispatch || !conf->group_cnt ||
+ bio_op(bio) == REQ_OP_READ) {
+ generic_make_request(bio);
+ return;
+ }
+ spin_lock(&conf->pending_bios_lock);
+ bio_list_add(&conf->pending_bios, bio);
+ spin_unlock(&conf->pending_bios_lock);
+ md_wakeup_thread(conf->mddev->thread);
+}
+
static void
raid5_end_read_request(struct bio *bi);
static void
trace_block_bio_remap(bdev_get_queue(bi->bi_bdev),
bi, disk_devt(conf->mddev->gendisk),
sh->dev[i].sector);
- generic_make_request(bi);
+ defer_bio_issue(conf, bi);
}
if (rrdev) {
if (s->syncing || s->expanding || s->expanded
trace_block_bio_remap(bdev_get_queue(rbi->bi_bdev),
rbi, disk_devt(conf->mddev->gendisk),
sh->dev[i].sector);
- generic_make_request(rbi);
+ defer_bio_issue(conf, rbi);
}
if (!rdev && !rrdev) {
if (op_is_write(op))
* like to flush data in journal to RAID disks first, so complex rmw
* is handled in the write patch (handle_stripe_dirtying).
*
+ * 2. when journal space is critical (R5C_LOG_CRITICAL=1)
+ *
+ * It is important to be able to flush all stripes in raid5-cache.
+ * Therefore, we need reserve some space on the journal device for
+ * these flushes. If flush operation includes pending writes to the
+ * stripe, we need to reserve (conf->raid_disk + 1) pages per stripe
+ * for the flush out. If we exclude these pending writes from flush
+ * operation, we only need (conf->max_degraded + 1) pages per stripe.
+ * Therefore, excluding pending writes in these cases enables more
+ * efficient use of the journal device.
+ *
+ * Note: To make sure the stripe makes progress, we only delay
+ * towrite for stripes with data already in journal (injournal > 0).
+ * When LOG_CRITICAL, stripes with injournal == 0 will be sent to
+ * no_space_stripes list.
+ *
*/
-static inline bool delay_towrite(struct r5dev *dev,
- struct stripe_head_state *s)
+static inline bool delay_towrite(struct r5conf *conf,
+ struct r5dev *dev,
+ struct stripe_head_state *s)
{
- return !test_bit(R5_OVERWRITE, &dev->flags) &&
- !test_bit(R5_Insync, &dev->flags) && s->injournal;
+ /* case 1 above */
+ if (!test_bit(R5_OVERWRITE, &dev->flags) &&
+ !test_bit(R5_Insync, &dev->flags) && s->injournal)
+ return true;
+ /* case 2 above */
+ if (test_bit(R5C_LOG_CRITICAL, &conf->cache_state) &&
+ s->injournal > 0)
+ return true;
+ return false;
}
static void
for (i = disks; i--; ) {
struct r5dev *dev = &sh->dev[i];
- if (dev->towrite && !delay_towrite(dev, s)) {
+ if (dev->towrite && !delay_towrite(conf, dev, s)) {
set_bit(R5_LOCKED, &dev->flags);
set_bit(R5_Wantdrain, &dev->flags);
if (!expand)
} 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 && !delay_towrite(dev, s)) ||
+ if (((dev->towrite && !delay_towrite(conf, dev, s)) ||
i == sh->pd_idx || i == sh->qd_idx ||
test_bit(R5_InJournal, &dev->flags)) &&
!test_bit(R5_LOCKED, &dev->flags) &&
}
}
- pr_debug("for sector %llu, rmw=%d rcw=%d\n",
- (unsigned long long)sh->sector, rmw, rcw);
+ pr_debug("for sector %llu state 0x%lx, rmw=%d rcw=%d\n",
+ (unsigned long long)sh->sector, sh->state, rmw, rcw);
set_bit(STRIPE_HANDLE, &sh->state);
if ((rmw < rcw || (rmw == rcw && conf->rmw_level == PARITY_PREFER_RMW)) && rmw > 0) {
/* prefer read-modify-write, but need to get some data */
for (i = disks; i--; ) {
struct r5dev *dev = &sh->dev[i];
- if (((dev->towrite && !delay_towrite(dev, s)) ||
+ if (((dev->towrite && !delay_towrite(conf, dev, s)) ||
i == sh->pd_idx || i == sh->qd_idx ||
test_bit(R5_InJournal, &dev->flags)) &&
!test_bit(R5_LOCKED, &dev->flags) &&
return 0;
}
/*
- * use bio_clone_mddev to make a copy of the bio
+ * use bio_clone_fast to make a copy of the bio
*/
- align_bi = bio_clone_mddev(raid_bio, GFP_NOIO, mddev);
+ align_bi = bio_clone_fast(raid_bio, GFP_NOIO, mddev->bio_set);
if (!align_bi)
return 0;
/*
rdev->recovery_offset >= end_sector)))
rdev = NULL;
}
+
+ if (r5c_big_stripe_cached(conf, align_bi->bi_iter.bi_sector)) {
+ rcu_read_unlock();
+ bio_put(align_bi);
+ return 0;
+ }
+
if (rdev) {
sector_t first_bad;
int bad_sectors;
* data on failed drives.
*/
if (rw == READ && mddev->degraded == 0 &&
- !r5c_is_writeback(conf->log) &&
mddev->reshape_position == MaxSector) {
bi = chunk_aligned_read(mddev, bi);
if (!bi)
mutex_unlock(&conf->cache_size_mutex);
}
+ flush_deferred_bios(conf);
+
r5l_flush_stripe_to_raid(conf->log);
async_tx_issue_pending_all();
atomic_set(&conf->active_stripes, 0);
atomic_set(&conf->preread_active_stripes, 0);
atomic_set(&conf->active_aligned_reads, 0);
+ bio_list_init(&conf->pending_bios);
+ spin_lock_init(&conf->pending_bios_lock);
+ conf->batch_bio_dispatch = true;
+ rdev_for_each(rdev, mddev) {
+ if (test_bit(Journal, &rdev->flags))
+ continue;
+ if (blk_queue_nonrot(bdev_get_queue(rdev->bdev))) {
+ conf->batch_bio_dispatch = false;
+ break;
+ }
+ }
+
conf->bypass_threshold = BYPASS_THRESHOLD;
conf->recovery_disabled = mddev->recovery_disabled - 1;
INIT_LIST_HEAD(&conf->r5c_full_stripe_list);
atomic_set(&conf->r5c_cached_partial_stripes, 0);
INIT_LIST_HEAD(&conf->r5c_partial_stripe_list);
+ atomic_set(&conf->r5c_flushing_full_stripes, 0);
+ atomic_set(&conf->r5c_flushing_partial_stripes, 0);
conf->level = mddev->new_level;
conf->chunk_sectors = mddev->new_chunk_sectors;
struct list_head r5c_full_stripe_list;
atomic_t r5c_cached_partial_stripes;
struct list_head r5c_partial_stripe_list;
+ atomic_t r5c_flushing_full_stripes;
+ atomic_t r5c_flushing_partial_stripes;
atomic_t empty_inactive_list_nr;
struct llist_head released_stripes;
int group_cnt;
int worker_cnt_per_group;
struct r5l_log *log;
+
+ struct bio_list pending_bios;
+ spinlock_t pending_bios_lock;
+ bool batch_bio_dispatch;
};
extern void r5c_check_cached_full_stripe(struct r5conf *conf);
extern struct md_sysfs_entry r5c_journal_mode;
extern void r5c_update_on_rdev_error(struct mddev *mddev);
+extern bool r5c_big_stripe_cached(struct r5conf *conf, sector_t sect);
#endif
#define bio_iter_last(bvec, iter) ((iter).bi_size == (bvec).bv_len)
-static inline unsigned bio_segments(struct bio *bio)
+static inline unsigned __bio_segments(struct bio *bio, struct bvec_iter *bvec)
{
unsigned segs = 0;
struct bio_vec bv;
break;
}
- bio_for_each_segment(bv, bio, iter)
+ __bio_for_each_segment(bv, bio, iter, *bvec)
segs++;
return segs;
}
+static inline unsigned bio_segments(struct bio *bio)
+{
+ return __bio_segments(bio, &bio->bi_iter);
+}
+
/*
* get a reference to a bio, so it won't disappear. the intended use is
* something like:
extern void __bio_clone_fast(struct bio *, struct bio *);
extern struct bio *bio_clone_fast(struct bio *, gfp_t, struct bio_set *);
extern struct bio *bio_clone_bioset(struct bio *, gfp_t, struct bio_set *bs);
+extern struct bio *bio_clone_bioset_partial(struct bio *, gfp_t,
+ struct bio_set *, int, int);
extern struct bio_set *fs_bio_set;
{
replace_slot(root, NULL, slot, item, true);
}
+EXPORT_SYMBOL(radix_tree_replace_slot);
/**
* radix_tree_iter_replace - replace item in a slot
projects / karo-tx-linux.git / commitdiff