diff options
Diffstat (limited to 'drivers/md/raid10.c')
| -rw-r--r-- | drivers/md/raid10.c | 1787 |
1 files changed, 1787 insertions, 0 deletions
diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c new file mode 100644 index 0000000..b100bfe --- /dev/null +++ b/drivers/md/raid10.c @@ -0,0 +1,1787 @@ +/* + * raid10.c : Multiple Devices driver for Linux + * + * Copyright (C) 2000-2004 Neil Brown + * + * RAID-10 support for md. + * + * Base on code in raid1.c. See raid1.c for futher copyright information. + * + * + * 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. + */ + +#include <linux/raid/raid10.h> + +/* + * RAID10 provides a combination of RAID0 and RAID1 functionality. + * The layout of data is defined by + * chunk_size + * raid_disks + * near_copies (stored in low byte of layout) + * far_copies (stored in second byte of layout) + * + * The data to be stored is divided into chunks using chunksize. + * Each device is divided into far_copies sections. + * In each section, chunks are laid out in a style similar to raid0, but + * near_copies copies of each chunk is stored (each on a different drive). + * The starting device for each section is offset near_copies from the starting + * device of the previous section. + * Thus there are (near_copies*far_copies) of each chunk, and each is on a different + * drive. + * near_copies and far_copies must be at least one, and their product is at most + * raid_disks. + */ + +/* + * Number of guaranteed r10bios in case of extreme VM load: + */ +#define NR_RAID10_BIOS 256 + +static void unplug_slaves(mddev_t *mddev); + +static void * r10bio_pool_alloc(unsigned int __nocast gfp_flags, void *data) +{ + conf_t *conf = data; + r10bio_t *r10_bio; + int size = offsetof(struct r10bio_s, devs[conf->copies]); + + /* allocate a r10bio with room for raid_disks entries in the bios array */ + r10_bio = kmalloc(size, gfp_flags); + if (r10_bio) + memset(r10_bio, 0, size); + else + unplug_slaves(conf->mddev); + + return r10_bio; +} + +static void r10bio_pool_free(void *r10_bio, void *data) +{ + kfree(r10_bio); +} + +#define RESYNC_BLOCK_SIZE (64*1024) +//#define RESYNC_BLOCK_SIZE PAGE_SIZE +#define RESYNC_SECTORS (RESYNC_BLOCK_SIZE >> 9) +#define RESYNC_PAGES ((RESYNC_BLOCK_SIZE + PAGE_SIZE-1) / PAGE_SIZE) +#define RESYNC_WINDOW (2048*1024) + +/* + * When performing a resync, we need to read and compare, so + * we need as many pages are there are copies. + * When performing a recovery, we need 2 bios, one for read, + * one for write (we recover only one drive per r10buf) + * + */ +static void * r10buf_pool_alloc(unsigned int __nocast gfp_flags, void *data) +{ + conf_t *conf = data; + struct page *page; + r10bio_t *r10_bio; + struct bio *bio; + int i, j; + int nalloc; + + r10_bio = r10bio_pool_alloc(gfp_flags, conf); + if (!r10_bio) { + unplug_slaves(conf->mddev); + return NULL; + } + + if (test_bit(MD_RECOVERY_SYNC, &conf->mddev->recovery)) + nalloc = conf->copies; /* resync */ + else + nalloc = 2; /* recovery */ + + /* + * Allocate bios. + */ + for (j = nalloc ; j-- ; ) { + bio = bio_alloc(gfp_flags, RESYNC_PAGES); + if (!bio) + goto out_free_bio; + r10_bio->devs[j].bio = bio; + } + /* + * Allocate RESYNC_PAGES data pages and attach them + * where needed. + */ + for (j = 0 ; j < nalloc; j++) { + bio = r10_bio->devs[j].bio; + for (i = 0; i < RESYNC_PAGES; i++) { + page = alloc_page(gfp_flags); + if (unlikely(!page)) + goto out_free_pages; + + bio->bi_io_vec[i].bv_page = page; + } + } + + return r10_bio; + +out_free_pages: + for ( ; i > 0 ; i--) + __free_page(bio->bi_io_vec[i-1].bv_page); + while (j--) + for (i = 0; i < RESYNC_PAGES ; i++) + __free_page(r10_bio->devs[j].bio->bi_io_vec[i].bv_page); + j = -1; +out_free_bio: + while ( ++j < nalloc ) + bio_put(r10_bio->devs[j].bio); + r10bio_pool_free(r10_bio, conf); + return NULL; +} + +static void r10buf_pool_free(void *__r10_bio, void *data) +{ + int i; + conf_t *conf = data; + r10bio_t *r10bio = __r10_bio; + int j; + + for (j=0; j < conf->copies; j++) { + struct bio *bio = r10bio->devs[j].bio; + if (bio) { + for (i = 0; i < RESYNC_PAGES; i++) { + __free_page(bio->bi_io_vec[i].bv_page); + bio->bi_io_vec[i].bv_page = NULL; + } + bio_put(bio); + } + } + r10bio_pool_free(r10bio, conf); +} + +static void put_all_bios(conf_t *conf, r10bio_t *r10_bio) +{ + int i; + + for (i = 0; i < conf->copies; i++) { + struct bio **bio = & r10_bio->devs[i].bio; + if (*bio) + bio_put(*bio); + *bio = NULL; + } +} + +static inline void free_r10bio(r10bio_t *r10_bio) +{ + unsigned long flags; + + conf_t *conf = mddev_to_conf(r10_bio->mddev); + + /* + * Wake up any possible resync thread that waits for the device + * to go idle. + */ + spin_lock_irqsave(&conf->resync_lock, flags); + if (!--conf->nr_pending) { + wake_up(&conf->wait_idle); + wake_up(&conf->wait_resume); + } + spin_unlock_irqrestore(&conf->resync_lock, flags); + + put_all_bios(conf, r10_bio); + mempool_free(r10_bio, conf->r10bio_pool); +} + +static inline void put_buf(r10bio_t *r10_bio) +{ + conf_t *conf = mddev_to_conf(r10_bio->mddev); + unsigned long flags; + + mempool_free(r10_bio, conf->r10buf_pool); + + spin_lock_irqsave(&conf->resync_lock, flags); + if (!conf->barrier) + BUG(); + --conf->barrier; + wake_up(&conf->wait_resume); + wake_up(&conf->wait_idle); + + if (!--conf->nr_pending) { + wake_up(&conf->wait_idle); + wake_up(&conf->wait_resume); + } + spin_unlock_irqrestore(&conf->resync_lock, flags); +} + +static void reschedule_retry(r10bio_t *r10_bio) +{ + unsigned long flags; + mddev_t *mddev = r10_bio->mddev; + conf_t *conf = mddev_to_conf(mddev); + + spin_lock_irqsave(&conf->device_lock, flags); + list_add(&r10_bio->retry_list, &conf->retry_list); + spin_unlock_irqrestore(&conf->device_lock, flags); + + md_wakeup_thread(mddev->thread); +} + +/* + * raid_end_bio_io() is called when we have finished servicing a mirrored + * operation and are ready to return a success/failure code to the buffer + * cache layer. + */ +static void raid_end_bio_io(r10bio_t *r10_bio) +{ + struct bio *bio = r10_bio->master_bio; + + bio_endio(bio, bio->bi_size, + test_bit(R10BIO_Uptodate, &r10_bio->state) ? 0 : -EIO); + free_r10bio(r10_bio); +} + +/* + * Update disk head position estimator based on IRQ completion info. + */ +static inline void update_head_pos(int slot, r10bio_t *r10_bio) +{ + conf_t *conf = mddev_to_conf(r10_bio->mddev); + + conf->mirrors[r10_bio->devs[slot].devnum].head_position = + r10_bio->devs[slot].addr + (r10_bio->sectors); +} + +static int raid10_end_read_request(struct bio *bio, unsigned int bytes_done, int error) +{ + int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags); + r10bio_t * r10_bio = (r10bio_t *)(bio->bi_private); + int slot, dev; + conf_t *conf = mddev_to_conf(r10_bio->mddev); + + if (bio->bi_size) + return 1; + + slot = r10_bio->read_slot; + dev = r10_bio->devs[slot].devnum; + /* + * this branch is our 'one mirror IO has finished' event handler: + */ + if (!uptodate) + md_error(r10_bio->mddev, conf->mirrors[dev].rdev); + else + /* + * Set R10BIO_Uptodate in our master bio, so that + * we will return a good error code to the higher + * levels even if IO on some other mirrored buffer fails. + * + * The 'master' represents the composite IO operation to + * user-side. So if something waits for IO, then it will + * wait for the 'master' bio. + */ + set_bit(R10BIO_Uptodate, &r10_bio->state); + + update_head_pos(slot, r10_bio); + + /* + * we have only one bio on the read side + */ + if (uptodate) + raid_end_bio_io(r10_bio); + else { + /* + * oops, read error: + */ + char b[BDEVNAME_SIZE]; + if (printk_ratelimit()) + printk(KERN_ERR "raid10: %s: rescheduling sector %llu\n", + bdevname(conf->mirrors[dev].rdev->bdev,b), (unsigned long long)r10_bio->sector); + reschedule_retry(r10_bio); + } + + rdev_dec_pending(conf->mirrors[dev].rdev, conf->mddev); + return 0; +} + +static int raid10_end_write_request(struct bio *bio, unsigned int bytes_done, int error) +{ + int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags); + r10bio_t * r10_bio = (r10bio_t *)(bio->bi_private); + int slot, dev; + conf_t *conf = mddev_to_conf(r10_bio->mddev); + + if (bio->bi_size) + return 1; + + for (slot = 0; slot < conf->copies; slot++) + if (r10_bio->devs[slot].bio == bio) + break; + dev = r10_bio->devs[slot].devnum; + + /* + * this branch is our 'one mirror IO has finished' event handler: + */ + if (!uptodate) + md_error(r10_bio->mddev, conf->mirrors[dev].rdev); + else + /* + * Set R10BIO_Uptodate in our master bio, so that + * we will return a good error code for to the higher + * levels even if IO on some other mirrored buffer fails. + * + * The 'master' represents the composite IO operation to + * user-side. So if something waits for IO, then it will + * wait for the 'master' bio. + */ + set_bit(R10BIO_Uptodate, &r10_bio->state); + + update_head_pos(slot, r10_bio); + + /* + * + * Let's see if all mirrored write operations have finished + * already. + */ + if (atomic_dec_and_test(&r10_bio->remaining)) { + md_write_end(r10_bio->mddev); + raid_end_bio_io(r10_bio); + } + + rdev_dec_pending(conf->mirrors[dev].rdev, conf->mddev); + return 0; +} + + +/* + * RAID10 layout manager + * Aswell as the chunksize and raid_disks count, there are two + * parameters: near_copies and far_copies. + * near_copies * far_copies must be <= raid_disks. + * Normally one of these will be 1. + * If both are 1, we get raid0. + * If near_copies == raid_disks, we get raid1. + * + * Chunks are layed out in raid0 style with near_copies copies of the + * first chunk, followed by near_copies copies of the next chunk and + * so on. + * If far_copies > 1, then after 1/far_copies of the array has been assigned + * as described above, we start again with a device offset of near_copies. + * So we effectively have another copy of the whole array further down all + * the drives, but with blocks on different drives. + * With this layout, and block is never stored twice on the one device. + * + * raid10_find_phys finds the sector offset of a given virtual sector + * on each device that it is on. If a block isn't on a device, + * that entry in the array is set to MaxSector. + * + * raid10_find_virt does the reverse mapping, from a device and a + * sector offset to a virtual address + */ + +static void raid10_find_phys(conf_t *conf, r10bio_t *r10bio) +{ + int n,f; + sector_t sector; + sector_t chunk; + sector_t stripe; + int dev; + + int slot = 0; + + /* now calculate first sector/dev */ + chunk = r10bio->sector >> conf->chunk_shift; + sector = r10bio->sector & conf->chunk_mask; + + chunk *= conf->near_copies; + stripe = chunk; + dev = sector_div(stripe, conf->raid_disks); + + sector += stripe << conf->chunk_shift; + + /* and calculate all the others */ + for (n=0; n < conf->near_copies; n++) { + int d = dev; + sector_t s = sector; + r10bio->devs[slot].addr = sector; + r10bio->devs[slot].devnum = d; + slot++; + + for (f = 1; f < conf->far_copies; f++) { + d += conf->near_copies; + if (d >= conf->raid_disks) + d -= conf->raid_disks; + s += conf->stride; + r10bio->devs[slot].devnum = d; + r10bio->devs[slot].addr = s; + slot++; + } + dev++; + if (dev >= conf->raid_disks) { + dev = 0; + sector += (conf->chunk_mask + 1); + } + } + BUG_ON(slot != conf->copies); +} + +static sector_t raid10_find_virt(conf_t *conf, sector_t sector, int dev) +{ + sector_t offset, chunk, vchunk; + + while (sector > conf->stride) { + sector -= conf->stride; + if (dev < conf->near_copies) + dev += conf->raid_disks - conf->near_copies; + else + dev -= conf->near_copies; + } + + offset = sector & conf->chunk_mask; + chunk = sector >> conf->chunk_shift; + vchunk = chunk * conf->raid_disks + dev; + sector_div(vchunk, conf->near_copies); + return (vchunk << conf->chunk_shift) + offset; +} + +/** + * raid10_mergeable_bvec -- tell bio layer if a two requests can be merged + * @q: request queue + * @bio: the buffer head that's been built up so far + * @biovec: the request that could be merged to it. + * + * Return amount of bytes we can accept at this offset + * If near_copies == raid_disk, there are no striping issues, + * but in that case, the function isn't called at all. + */ +static int raid10_mergeable_bvec(request_queue_t *q, struct bio *bio, + struct bio_vec *bio_vec) +{ + mddev_t *mddev = q->queuedata; + sector_t sector = bio->bi_sector + get_start_sect(bio->bi_bdev); + int max; + unsigned int chunk_sectors = mddev->chunk_size >> 9; + unsigned int bio_sectors = bio->bi_size >> 9; + + max = (chunk_sectors - ((sector & (chunk_sectors - 1)) + bio_sectors)) << 9; + if (max < 0) max = 0; /* bio_add cannot handle a negative return */ + if (max <= bio_vec->bv_len && bio_sectors == 0) + return bio_vec->bv_len; + else + return max; +} + +/* + * This routine returns the disk from which the requested read should + * be done. There is a per-array 'next expected sequential IO' sector + * number - if this matches on the next IO then we use the last disk. + * There is also a per-disk 'last know head position' sector that is + * maintained from IRQ contexts, both the normal and the resync IO + * completion handlers update this position correctly. If there is no + * perfect sequential match then we pick the disk whose head is closest. + * + * If there are 2 mirrors in the same 2 devices, performance degrades + * because position is mirror, not device based. + * + * The rdev for the device selected will have nr_pending incremented. + */ + +/* + * FIXME: possibly should rethink readbalancing and do it differently + * depending on near_copies / far_copies geometry. + */ +static int read_balance(conf_t *conf, r10bio_t *r10_bio) +{ + const unsigned long this_sector = r10_bio->sector; + int disk, slot, nslot; + const int sectors = r10_bio->sectors; + sector_t new_distance, current_distance; + + raid10_find_phys(conf, r10_bio); + rcu_read_lock(); + /* + * Check if we can balance. We can balance on the whole + * device if no resync is going on, or below the resync window. + * We take the first readable disk when above the resync window. + */ + if (conf->mddev->recovery_cp < MaxSector + && (this_sector + sectors >= conf->next_resync)) { + /* make sure that disk is operational */ + slot = 0; + disk = r10_bio->devs[slot].devnum; + + while (!conf->mirrors[disk].rdev || + !conf->mirrors[disk].rdev->in_sync) { + slot++; + if (slot == conf->copies) { + slot = 0; + disk = -1; + break; + } + disk = r10_bio->devs[slot].devnum; + } + goto rb_out; + } + + + /* make sure the disk is operational */ + slot = 0; + disk = r10_bio->devs[slot].devnum; + while (!conf->mirrors[disk].rdev || + !conf->mirrors[disk].rdev->in_sync) { + slot ++; + if (slot == conf->copies) { + disk = -1; + goto rb_out; + } + disk = r10_bio->devs[slot].devnum; + } + + + current_distance = abs(this_sector - conf->mirrors[disk].head_position); + + /* Find the disk whose head is closest */ + + for (nslot = slot; nslot < conf->copies; nslot++) { + int ndisk = r10_bio->devs[nslot].devnum; + + + if (!conf->mirrors[ndisk].rdev || + !conf->mirrors[ndisk].rdev->in_sync) + continue; + + if (!atomic_read(&conf->mirrors[ndisk].rdev->nr_pending)) { + disk = ndisk; + slot = nslot; + break; + } + new_distance = abs(r10_bio->devs[nslot].addr - + conf->mirrors[ndisk].head_position); + if (new_distance < current_distance) { + current_distance = new_distance; + disk = ndisk; + slot = nslot; + } + } + +rb_out: + r10_bio->read_slot = slot; +/* conf->next_seq_sect = this_sector + sectors;*/ + + if (disk >= 0 && conf->mirrors[disk].rdev) + atomic_inc(&conf->mirrors[disk].rdev->nr_pending); + rcu_read_unlock(); + + return disk; +} + +static void unplug_slaves(mddev_t *mddev) +{ + conf_t *conf = mddev_to_conf(mddev); + int i; + + rcu_read_lock(); + for (i=0; i<mddev->raid_disks; i++) { + mdk_rdev_t *rdev = conf->mirrors[i].rdev; + if (rdev && !rdev->faulty && atomic_read(&rdev->nr_pending)) { + request_queue_t *r_queue = bdev_get_queue(rdev->bdev); + + atomic_inc(&rdev->nr_pending); + rcu_read_unlock(); + + if (r_queue->unplug_fn) + r_queue->unplug_fn(r_queue); + + rdev_dec_pending(rdev, mddev); + rcu_read_lock(); + } + } + rcu_read_unlock(); +} + +static void raid10_unplug(request_queue_t *q) +{ + unplug_slaves(q->queuedata); +} + +static int raid10_issue_flush(request_queue_t *q, struct gendisk *disk, + sector_t *error_sector) +{ + mddev_t *mddev = q->queuedata; + conf_t *conf = mddev_to_conf(mddev); + int i, ret = 0; + + rcu_read_lock(); + for (i=0; i<mddev->raid_disks && ret == 0; i++) { + mdk_rdev_t *rdev = conf->mirrors[i].rdev; + if (rdev && !rdev->faulty) { + struct block_device *bdev = rdev->bdev; + request_queue_t *r_queue = bdev_get_queue(bdev); + + if (!r_queue->issue_flush_fn) + ret = -EOPNOTSUPP; + else { + atomic_inc(&rdev->nr_pending); + rcu_read_unlock(); + ret = r_queue->issue_flush_fn(r_queue, bdev->bd_disk, + error_sector); + rdev_dec_pending(rdev, mddev); + rcu_read_lock(); + } + } + } + rcu_read_unlock(); + return ret; +} + +/* + * Throttle resync depth, so that we can both get proper overlapping of + * requests, but are still able to handle normal requests quickly. + */ +#define RESYNC_DEPTH 32 + +static void device_barrier(conf_t *conf, sector_t sect) +{ + spin_lock_irq(&conf->resync_lock); + wait_event_lock_irq(conf->wait_idle, !waitqueue_active(&conf->wait_resume), + conf->resync_lock, unplug_slaves(conf->mddev)); + + if (!conf->barrier++) { + wait_event_lock_irq(conf->wait_idle, !conf->nr_pending, + conf->resync_lock, unplug_slaves(conf->mddev)); + if (conf->nr_pending) + BUG(); + } + wait_event_lock_irq(conf->wait_resume, conf->barrier < RESYNC_DEPTH, + conf->resync_lock, unplug_slaves(conf->mddev)); + conf->next_resync = sect; + spin_unlock_irq(&conf->resync_lock); +} + +static int make_request(request_queue_t *q, struct bio * bio) +{ + mddev_t *mddev = q->queuedata; + conf_t *conf = mddev_to_conf(mddev); + mirror_info_t *mirror; + r10bio_t *r10_bio; + struct bio *read_bio; + int i; + int chunk_sects = conf->chunk_mask + 1; + + /* If this request crosses a chunk boundary, we need to + * split it. This will only happen for 1 PAGE (or less) requests. + */ + if (unlikely( (bio->bi_sector & conf->chunk_mask) + (bio->bi_size >> 9) + > chunk_sects && + conf->near_copies < conf->raid_disks)) { + struct bio_pair *bp; + /* Sanity check -- queue functions should prevent this happening */ + if (bio->bi_vcnt != 1 || + bio->bi_idx != 0) + goto bad_map; + /* This is a one page bio that upper layers + * refuse to split for us, so we need to split it. + */ + bp = bio_split(bio, bio_split_pool, + chunk_sects - (bio->bi_sector & (chunk_sects - 1)) ); + if (make_request(q, &bp->bio1)) + generic_make_request(&bp->bio1); + if (make_request(q, &bp->bio2)) + generic_make_request(&bp->bio2); + + bio_pair_release(bp); + return 0; + bad_map: + printk("raid10_make_request bug: can't convert block across chunks" + " or bigger than %dk %llu %d\n", chunk_sects/2, + (unsigned long long)bio->bi_sector, bio->bi_size >> 10); + + bio_io_error(bio, bio->bi_size); + return 0; + } + + /* + * Register the new request and wait if the reconstruction + * thread has put up a bar for new requests. + * Continue immediately if no resync is active currently. + */ + spin_lock_irq(&conf->resync_lock); + wait_event_lock_irq(conf->wait_resume, !conf->barrier, conf->resync_lock, ); + conf->nr_pending++; + spin_unlock_irq(&conf->resync_lock); + + if (bio_data_dir(bio)==WRITE) { + disk_stat_inc(mddev->gendisk, writes); + disk_stat_add(mddev->gendisk, write_sectors, bio_sectors(bio)); + } else { + disk_stat_inc(mddev->gendisk, reads); + disk_stat_add(mddev->gendisk, read_sectors, bio_sectors(bio)); + } + + r10_bio = mempool_alloc(conf->r10bio_pool, GFP_NOIO); + + r10_bio->master_bio = bio; + r10_bio->sectors = bio->bi_size >> 9; + + r10_bio->mddev = mddev; + r10_bio->sector = bio->bi_sector; + + if (bio_data_dir(bio) == READ) { + /* + * read balancing logic: + */ + int disk = read_balance(conf, r10_bio); + int slot = r10_bio->read_slot; + if (disk < 0) { + raid_end_bio_io(r10_bio); + return 0; + } + mirror = conf->mirrors + disk; + + read_bio = bio_clone(bio, GFP_NOIO); + + r10_bio->devs[slot].bio = read_bio; + + read_bio->bi_sector = r10_bio->devs[slot].addr + + mirror->rdev->data_offset; + read_bio->bi_bdev = mirror->rdev->bdev; + read_bio->bi_end_io = raid10_end_read_request; + read_bio->bi_rw = READ; + read_bio->bi_private = r10_bio; + + generic_make_request(read_bio); + return 0; + } + + /* + * WRITE: + */ + /* first select target devices under spinlock and + * inc refcount on their rdev. Record them by setting + * bios[x] to bio + */ + raid10_find_phys(conf, r10_bio); + rcu_read_lock(); + for (i = 0; i < conf->copies; i++) { + int d = r10_bio->devs[i].devnum; + if (conf->mirrors[d].rdev && + !conf->mirrors[d].rdev->faulty) { + atomic_inc(&conf->mirrors[d].rdev->nr_pending); + r10_bio->devs[i].bio = bio; + } else + r10_bio->devs[i].bio = NULL; + } + rcu_read_unlock(); + + atomic_set(&r10_bio->remaining, 1); + md_write_start(mddev); + for (i = 0; i < conf->copies; i++) { + struct bio *mbio; + int d = r10_bio->devs[i].devnum; + if (!r10_bio->devs[i].bio) + continue; + + mbio = bio_clone(bio, GFP_NOIO); + r10_bio->devs[i].bio = mbio; + + mbio->bi_sector = r10_bio->devs[i].addr+ + conf->mirrors[d].rdev->data_offset; + mbio->bi_bdev = conf->mirrors[d].rdev->bdev; + mbio->bi_end_io = raid10_end_write_request; + mbio->bi_rw = WRITE; + mbio->bi_private = r10_bio; + + atomic_inc(&r10_bio->remaining); + generic_make_request(mbio); + } + + if (atomic_dec_and_test(&r10_bio->remaining)) { + md_write_end(mddev); + raid_end_bio_io(r10_bio); + } + + return 0; +} + +static void status(struct seq_file *seq, mddev_t *mddev) +{ + conf_t *conf = mddev_to_conf(mddev); + int i; + + if (conf->near_copies < conf->raid_disks) + seq_printf(seq, " %dK chunks", mddev->chunk_size/1024); + if (conf->near_copies > 1) + seq_printf(seq, " %d near-copies", conf->near_copies); + if (conf->far_copies > 1) + seq_printf(seq, " %d far-copies", conf->far_copies); + + seq_printf(seq, " [%d/%d] [", conf->raid_disks, + conf->working_disks); + for (i = 0; i < conf->raid_disks; i++) + seq_printf(seq, "%s", + conf->mirrors[i].rdev && + conf->mirrors[i].rdev->in_sync ? "U" : "_"); + seq_printf(seq, "]"); +} + +static void error(mddev_t *mddev, mdk_rdev_t *rdev) +{ + char b[BDEVNAME_SIZE]; + conf_t *conf = mddev_to_conf(mddev); + + /* + * If it is not operational, then we have already marked it as dead + * else if it is the last working disks, ignore the error, let the + * next level up know. + * else mark the drive as failed + */ + if (rdev->in_sync + && conf->working_disks == 1) + /* + * Don't fail the drive, just return an IO error. + * The test should really be more sophisticated than + * "working_disks == 1", but it isn't critical, and + * can wait until we do more sophisticated "is the drive + * really dead" tests... + */ + return; + if (rdev->in_sync) { + mddev->degraded++; + conf->working_disks--; + /* + * if recovery is running, make sure it aborts. + */ + set_bit(MD_RECOVERY_ERR, &mddev->recovery); + } + rdev->in_sync = 0; + rdev->faulty = 1; + mddev->sb_dirty = 1; + printk(KERN_ALERT "raid10: Disk failure on %s, disabling device. \n" + " Operation continuing on %d devices\n", + bdevname(rdev->bdev,b), conf->working_disks); +} + +static void print_conf(conf_t *conf) +{ + int i; + mirror_info_t *tmp; + + printk("RAID10 conf printout:\n"); + if (!conf) { + printk("(!conf)\n"); + return; + } + printk(" --- wd:%d rd:%d\n", conf->working_disks, + conf->raid_disks); + + for (i = 0; i < conf->raid_disks; i++) { + char b[BDEVNAME_SIZE]; + tmp = conf->mirrors + i; + if (tmp->rdev) + printk(" disk %d, wo:%d, o:%d, dev:%s\n", + i, !tmp->rdev->in_sync, !tmp->rdev->faulty, + bdevname(tmp->rdev->bdev,b)); + } +} + +static void close_sync(conf_t *conf) +{ + spin_lock_irq(&conf->resync_lock); + wait_event_lock_irq(conf->wait_resume, !conf->barrier, + conf->resync_lock, unplug_slaves(conf->mddev)); + spin_unlock_irq(&conf->resync_lock); + + if (conf->barrier) BUG(); + if (waitqueue_active(&conf->wait_idle)) BUG(); + + mempool_destroy(conf->r10buf_pool); + conf->r10buf_pool = NULL; +} + +static int raid10_spare_active(mddev_t *mddev) +{ + int i; + conf_t *conf = mddev->private; + mirror_info_t *tmp; + + /* + * Find all non-in_sync disks within the RAID10 configuration + * and mark them in_sync + */ + for (i = 0; i < conf->raid_disks; i++) { + tmp = conf->mirrors + i; + if (tmp->rdev + && !tmp->rdev->faulty + && !tmp->rdev->in_sync) { + conf->working_disks++; + mddev->degraded--; + tmp->rdev->in_sync = 1; + } + } + + print_conf(conf); + return 0; +} + + +static int raid10_add_disk(mddev_t *mddev, mdk_rdev_t *rdev) +{ + conf_t *conf = mddev->private; + int found = 0; + int mirror; + mirror_info_t *p; + + if (mddev->recovery_cp < MaxSector) + /* only hot-add to in-sync arrays, as recovery is + * very different from resync + */ + return 0; + + for (mirror=0; mirror < mddev->raid_disks; mirror++) + if ( !(p=conf->mirrors+mirror)->rdev) { + + blk_queue_stack_limits(mddev->queue, + rdev->bdev->bd_disk->queue); + /* as we don't honour merge_bvec_fn, we must never risk + * violating it, so limit ->max_sector to one PAGE, as + * a one page request is never in violation. + */ + if (rdev->bdev->bd_disk->queue->merge_bvec_fn && + mddev->queue->max_sectors > (PAGE_SIZE>>9)) + mddev->queue->max_sectors = (PAGE_SIZE>>9); + + p->head_position = 0; + rdev->raid_disk = mirror; + found = 1; + p->rdev = rdev; + break; + } + + print_conf(conf); + return found; +} + +static int raid10_remove_disk(mddev_t *mddev, int number) +{ + conf_t *conf = mddev->private; + int err = 0; + mdk_rdev_t *rdev; + mirror_info_t *p = conf->mirrors+ number; + + print_conf(conf); + rdev = p->rdev; + if (rdev) { + if (rdev->in_sync || + atomic_read(&rdev->nr_pending)) { + err = -EBUSY; + goto abort; + } + p->rdev = NULL; + synchronize_kernel(); + if (atomic_read(&rdev->nr_pending)) { + /* lost the race, try later */ + err = -EBUSY; + p->rdev = rdev; + } + } +abort: + + print_conf(conf); + return err; +} + + +static int end_sync_read(struct bio *bio, unsigned int bytes_done, int error) +{ + int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags); + r10bio_t * r10_bio = (r10bio_t *)(bio->bi_private); + conf_t *conf = mddev_to_conf(r10_bio->mddev); + int i,d; + + if (bio->bi_size) + return 1; + + for (i=0; i<conf->copies; i++) + if (r10_bio->devs[i].bio == bio) + break; + if (i == conf->copies) + BUG(); + update_head_pos(i, r10_bio); + d = r10_bio->devs[i].devnum; + if (!uptodate) + md_error(r10_bio->mddev, + conf->mirrors[d].rdev); + + /* for reconstruct, we always reschedule after a read. + * for resync, only after all reads + */ + if (test_bit(R10BIO_IsRecover, &r10_bio->state) || + atomic_dec_and_test(&r10_bio->remaining)) { + /* we have read all the blocks, + * do the comparison in process context in raid10d + */ + reschedule_retry(r10_bio); + } + rdev_dec_pending(conf->mirrors[d].rdev, conf->mddev); + return 0; +} + +static int end_sync_write(struct bio *bio, unsigned int bytes_done, int error) +{ + int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags); + r10bio_t * r10_bio = (r10bio_t *)(bio->bi_private); + mddev_t *mddev = r10_bio->mddev; + conf_t *conf = mddev_to_conf(mddev); + int i,d; + + if (bio->bi_size) + return 1; + + for (i = 0; i < conf->copies; i++) + if (r10_bio->devs[i].bio == bio) + break; + d = r10_bio->devs[i].devnum; + + if (!uptodate) + md_error(mddev, conf->mirrors[d].rdev); + update_head_pos(i, r10_bio); + + while (atomic_dec_and_test(&r10_bio->remaining)) { + if (r10_bio->master_bio == NULL) { + /* the primary of several recovery bios */ + md_done_sync(mddev, r10_bio->sectors, 1); + put_buf(r10_bio); + break; + } else { + r10bio_t *r10_bio2 = (r10bio_t *)r10_bio->master_bio; + put_buf(r10_bio); + r10_bio = r10_bio2; + } + } + rdev_dec_pending(conf->mirrors[d].rdev, mddev); + return 0; +} + +/* + * Note: sync and recover and handled very differently for raid10 + * This code is for resync. + * For resync, we read through virtual addresses and read all blocks. + * If there is any error, we schedule a write. The lowest numbered + * drive is authoritative. + * However requests come for physical address, so we need to map. + * For every physical address there are raid_disks/copies virtual addresses, + * which is always are least one, but is not necessarly an integer. + * This means that a physical address can span multiple chunks, so we may + * have to submit multiple io requests for a single sync request. + */ +/* + * We check if all blocks are in-sync and only write to blocks that + * aren't in sync + */ +static void sync_request_write(mddev_t *mddev, r10bio_t *r10_bio) +{ + conf_t *conf = mddev_to_conf(mddev); + int i, first; + struct bio *tbio, *fbio; + + atomic_set(&r10_bio->remaining, 1); + + /* find the first device with a block */ + for (i=0; i<conf->copies; i++) + if (test_bit(BIO_UPTODATE, &r10_bio->devs[i].bio->bi_flags)) + break; + + if (i == conf->copies) + goto done; + + first = i; + fbio = r10_bio->devs[i].bio; + + /* now find blocks with errors */ + for (i=first+1 ; i < conf->copies ; i++) { + int vcnt, j, d; + + if (!test_bit(BIO_UPTODATE, &r10_bio->devs[i].bio->bi_flags)) + continue; + /* We know that the bi_io_vec layout is the same for + * both 'first' and 'i', so we just compare them. + * All vec entries are PAGE_SIZE; + */ + tbio = r10_bio->devs[i].bio; + vcnt = r10_bio->sectors >> (PAGE_SHIFT-9); + for (j = 0; j < vcnt; j++) + if (memcmp(page_address(fbio->bi_io_vec[j].bv_page), + page_address(tbio->bi_io_vec[j].bv_page), + PAGE_SIZE)) + break; + if (j == vcnt) + continue; + /* Ok, we need to write this bio + * First we need to fixup bv_offset, bv_len and + * bi_vecs, as the read request might have corrupted these + */ + tbio->bi_vcnt = vcnt; + tbio->bi_size = r10_bio->sectors << 9; + tbio->bi_idx = 0; + tbio->bi_phys_segments = 0; + tbio->bi_hw_segments = 0; + tbio->bi_hw_front_size = 0; + tbio->bi_hw_back_size = 0; + tbio->bi_flags &= ~(BIO_POOL_MASK - 1); + tbio->bi_flags |= 1 << BIO_UPTODATE; + tbio->bi_next = NULL; + tbio->bi_rw = WRITE; + tbio->bi_private = r10_bio; + tbio->bi_sector = r10_bio->devs[i].addr; + + for (j=0; j < vcnt ; j++) { + tbio->bi_io_vec[j].bv_offset = 0; + tbio->bi_io_vec[j].bv_len = PAGE_SIZE; + + memcpy(page_address(tbio->bi_io_vec[j].bv_page), + page_address(fbio->bi_io_vec[j].bv_page), + PAGE_SIZE); + } + tbio->bi_end_io = end_sync_write; + + d = r10_bio->devs[i].devnum; + atomic_inc(&conf->mirrors[d].rdev->nr_pending); + atomic_inc(&r10_bio->remaining); + md_sync_acct(conf->mirrors[d].rdev->bdev, tbio->bi_size >> 9); + + tbio->bi_sector += conf->mirrors[d].rdev->data_offset; + tbio->bi_bdev = conf->mirrors[d].rdev->bdev; + generic_make_request(tbio); + } + +done: + if (atomic_dec_and_test(&r10_bio->remaining)) { + md_done_sync(mddev, r10_bio->sectors, 1); + put_buf(r10_bio); + } +} + +/* + * Now for the recovery code. + * Recovery happens across physical sectors. + * We recover all non-is_sync drives by finding the virtual address of + * each, and then choose a working drive that also has that virt address. + * There is a separate r10_bio for each non-in_sync drive. + * Only the first two slots are in use. The first for reading, + * The second for writing. + * + */ + +static void recovery_request_write(mddev_t *mddev, r10bio_t *r10_bio) +{ + conf_t *conf = mddev_to_conf(mddev); + int i, d; + struct bio *bio, *wbio; + + + /* move the pages across to the second bio + * and submit the write request + */ + bio = r10_bio->devs[0].bio; + wbio = r10_bio->devs[1].bio; + for (i=0; i < wbio->bi_vcnt; i++) { + struct page *p = bio->bi_io_vec[i].bv_page; + bio->bi_io_vec[i].bv_page = wbio->bi_io_vec[i].bv_page; + wbio->bi_io_vec[i].bv_page = p; + } + d = r10_bio->devs[1].devnum; + + atomic_inc(&conf->mirrors[d].rdev->nr_pending); + md_sync_acct(conf->mirrors[d].rdev->bdev, wbio->bi_size >> 9); + generic_make_request(wbio); +} + + +/* + * This is a kernel thread which: + * + * 1. Retries failed read operations on working mirrors. + * 2. Updates the raid superblock when problems encounter. + * 3. Performs writes following reads for array syncronising. + */ + +static void raid10d(mddev_t *mddev) +{ + r10bio_t *r10_bio; + struct bio *bio; + unsigned long flags; + conf_t *conf = mddev_to_conf(mddev); + struct list_head *head = &conf->retry_list; + int unplug=0; + mdk_rdev_t *rdev; + + md_check_recovery(mddev); + md_handle_safemode(mddev); + + for (;;) { + char b[BDEVNAME_SIZE]; + spin_lock_irqsave(&conf->device_lock, flags); + if (list_empty(head)) + break; + r10_bio = list_entry(head->prev, r10bio_t, retry_list); + list_del(head->prev); + spin_unlock_irqrestore(&conf->device_lock, flags); + + mddev = r10_bio->mddev; + conf = mddev_to_conf(mddev); + if (test_bit(R10BIO_IsSync, &r10_bio->state)) { + sync_request_write(mddev, r10_bio); + unplug = 1; + } else if (test_bit(R10BIO_IsRecover, &r10_bio->state)) { + recovery_request_write(mddev, r10_bio); + unplug = 1; + } else { + int mirror; + bio = r10_bio->devs[r10_bio->read_slot].bio; + r10_bio->devs[r10_bio->read_slot].bio = NULL; + bio_put(bio); + mirror = read_balance(conf, r10_bio); + if (mirror == -1) { + printk(KERN_ALERT "raid10: %s: unrecoverable I/O" + " read error for block %llu\n", + bdevname(bio->bi_bdev,b), + (unsigned long long)r10_bio->sector); + raid_end_bio_io(r10_bio); + } else { + rdev = conf->mirrors[mirror].rdev; + if (printk_ratelimit()) + printk(KERN_ERR "raid10: %s: redirecting sector %llu to" + " another mirror\n", + bdevname(rdev->bdev,b), + (unsigned long long)r10_bio->sector); + bio = bio_clone(r10_bio->master_bio, GFP_NOIO); + r10_bio->devs[r10_bio->read_slot].bio = bio; + bio->bi_sector = r10_bio->devs[r10_bio->read_slot].addr + + rdev->data_offset; + bio->bi_bdev = rdev->bdev; + bio->bi_rw = READ; + bio->bi_private = r10_bio; + bio->bi_end_io = raid10_end_read_request; + unplug = 1; + generic_make_request(bio); + } + } + } + spin_unlock_irqrestore(&conf->device_lock, flags); + if (unplug) + unplug_slaves(mddev); +} + + +static int init_resync(conf_t *conf) +{ + int buffs; + + buffs = RESYNC_WINDOW / RESYNC_BLOCK_SIZE; + if (conf->r10buf_pool) + BUG(); + conf->r10buf_pool = mempool_create(buffs, r10buf_pool_alloc, r10buf_pool_free, conf); + if (!conf->r10buf_pool) + return -ENOMEM; + conf->next_resync = 0; + return 0; +} + +/* + * perform a "sync" on one "block" + * + * We need to make sure that no normal I/O request - particularly write + * requests - conflict with active sync requests. + * + * This is achieved by tracking pending requests and a 'barrier' concept + * that can be installed to exclude normal IO requests. + * + * Resync and recovery are handled very differently. + * We differentiate by looking at MD_RECOVERY_SYNC in mddev->recovery. + * + * For resync, we iterate over virtual addresses, read all copies, + * and update if there are differences. If only one copy is live, + * skip it. + * For recovery, we iterate over physical addresses, read a good + * value for each non-in_sync drive, and over-write. + * + * So, for recovery we may have several outstanding complex requests for a + * given address, one for each out-of-sync device. We model this by allocating + * a number of r10_bio structures, one for each out-of-sync device. + * As we setup these structures, we collect all bio's together into a list + * which we then process collectively to add pages, and then process again + * to pass to generic_make_request. + * + * The r10_bio structures are linked using a borrowed master_bio pointer. + * This link is counted in ->remaining. When the r10_bio that points to NULL + * has its remaining count decremented to 0, the whole complex operation + * is complete. + * + */ + +static int sync_request(mddev_t *mddev, sector_t sector_nr, int go_faster) +{ + conf_t *conf = mddev_to_conf(mddev); + r10bio_t *r10_bio; + struct bio *biolist = NULL, *bio; + sector_t max_sector, nr_sectors; + int disk; + int i; + + sector_t sectors_skipped = 0; + int chunks_skipped = 0; + + if (!conf->r10buf_pool) + if (init_resync(conf)) + return -ENOMEM; + + skipped: + max_sector = mddev->size << 1; + if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) + max_sector = mddev->resync_max_sectors; + if (sector_nr >= max_sector) { + close_sync(conf); + return sectors_skipped; + } + if (chunks_skipped >= conf->raid_disks) { + /* if there has been nothing to do on any drive, + * then there is nothing to do at all.. + */ + sector_t sec = max_sector - sector_nr; + md_done_sync(mddev, sec, 1); + return sec + sectors_skipped; + } + + /* make sure whole request will fit in a chunk - if chunks + * are meaningful + */ + if (conf->near_copies < conf->raid_disks && + max_sector > (sector_nr | conf->chunk_mask)) + max_sector = (sector_nr | conf->chunk_mask) + 1; + /* + * If there is non-resync activity waiting for us then + * put in a delay to throttle resync. + */ + if (!go_faster && waitqueue_active(&conf->wait_resume)) + msleep_interruptible(1000); + device_barrier(conf, sector_nr + RESYNC_SECTORS); + + /* Again, very different code for resync and recovery. + * Both must result in an r10bio with a list of bios that + * have bi_end_io, bi_sector, bi_bdev set, + * and bi_private set to the r10bio. + * For recovery, we may actually create several r10bios + * with 2 bios in each, that correspond to the bios in the main one. + * In this case, the subordinate r10bios link back through a + * borrowed master_bio pointer, and the counter in the master + * includes a ref from each subordinate. + */ + /* First, we decide what to do and set ->bi_end_io + * To end_sync_read if we want to read, and + * end_sync_write if we will want to write. + */ + + if (!test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) { + /* recovery... the complicated one */ + int i, j, k; + r10_bio = NULL; + + for (i=0 ; i<conf->raid_disks; i++) + if (conf->mirrors[i].rdev && + !conf->mirrors[i].rdev->in_sync) { + /* want to reconstruct this device */ + r10bio_t *rb2 = r10_bio; + + r10_bio = mempool_alloc(conf->r10buf_pool, GFP_NOIO); + spin_lock_irq(&conf->resync_lock); + conf->nr_pending++; + if (rb2) conf->barrier++; + spin_unlock_irq(&conf->resync_lock); + atomic_set(&r10_bio->remaining, 0); + + r10_bio->master_bio = (struct bio*)rb2; + if (rb2) + atomic_inc(&rb2->remaining); + r10_bio->mddev = mddev; + set_bit(R10BIO_IsRecover, &r10_bio->state); + r10_bio->sector = raid10_find_virt(conf, sector_nr, i); + raid10_find_phys(conf, r10_bio); + for (j=0; j<conf->copies;j++) { + int d = r10_bio->devs[j].devnum; + if (conf->mirrors[d].rdev && + conf->mirrors[d].rdev->in_sync) { + /* This is where we read from */ + bio = r10_bio->devs[0].bio; + bio->bi_next = biolist; + biolist = bio; + bio->bi_private = r10_bio; + bio->bi_end_io = end_sync_read; + bio->bi_rw = 0; + bio->bi_sector = r10_bio->devs[j].addr + + conf->mirrors[d].rdev->data_offset; + bio->bi_bdev = conf->mirrors[d].rdev->bdev; + atomic_inc(&conf->mirrors[d].rdev->nr_pending); + atomic_inc(&r10_bio->remaining); + /* and we write to 'i' */ + + for (k=0; k<conf->copies; k++) + if (r10_bio->devs[k].devnum == i) + break; + bio = r10_bio->devs[1].bio; + bio->bi_next = biolist; + biolist = bio; + bio->bi_private = r10_bio; + bio->bi_end_io = end_sync_write; + bio->bi_rw = 1; + bio->bi_sector = r10_bio->devs[k].addr + + conf->mirrors[i].rdev->data_offset; + bio->bi_bdev = conf->mirrors[i].rdev->bdev; + + r10_bio->devs[0].devnum = d; + r10_bio->devs[1].devnum = i; + + break; + } + } + if (j == conf->copies) { + BUG(); + } + } + if (biolist == NULL) { + while (r10_bio) { + r10bio_t *rb2 = r10_bio; + r10_bio = (r10bio_t*) rb2->master_bio; + rb2->master_bio = NULL; + put_buf(rb2); + } + goto giveup; + } + } else { + /* resync. Schedule a read for every block at this virt offset */ + int count = 0; + r10_bio = mempool_alloc(conf->r10buf_pool, GFP_NOIO); + + spin_lock_irq(&conf->resync_lock); + conf->nr_pending++; + spin_unlock_irq(&conf->resync_lock); + + r10_bio->mddev = mddev; + atomic_set(&r10_bio->remaining, 0); + + r10_bio->master_bio = NULL; + r10_bio->sector = sector_nr; + set_bit(R10BIO_IsSync, &r10_bio->state); + raid10_find_phys(conf, r10_bio); + r10_bio->sectors = (sector_nr | conf->chunk_mask) - sector_nr +1; + + for (i=0; i<conf->copies; i++) { + int d = r10_bio->devs[i].devnum; + bio = r10_bio->devs[i].bio; + bio->bi_end_io = NULL; + if (conf->mirrors[d].rdev == NULL || + conf->mirrors[d].rdev->faulty) + continue; + atomic_inc(&conf->mirrors[d].rdev->nr_pending); + atomic_inc(&r10_bio->remaining); + bio->bi_next = biolist; + biolist = bio; + bio->bi_private = r10_bio; + bio->bi_end_io = end_sync_read; + bio->bi_rw = 0; + bio->bi_sector = r10_bio->devs[i].addr + + conf->mirrors[d].rdev->data_offset; + bio->bi_bdev = conf->mirrors[d].rdev->bdev; + count++; + } + + if (count < 2) { + for (i=0; i<conf->copies; i++) { + int d = r10_bio->devs[i].devnum; + if (r10_bio->devs[i].bio->bi_end_io) + rdev_dec_pending(conf->mirrors[d].rdev, mddev); + } + put_buf(r10_bio); + biolist = NULL; + goto giveup; + } + } + + for (bio = biolist; bio ; bio=bio->bi_next) { + + bio->bi_flags &= ~(BIO_POOL_MASK - 1); + if (bio->bi_end_io) + bio->bi_flags |= 1 << BIO_UPTODATE; + bio->bi_vcnt = 0; + bio->bi_idx = 0; + bio->bi_phys_segments = 0; + bio->bi_hw_segments = 0; + bio->bi_size = 0; + } + + nr_sectors = 0; + do { + struct page *page; + int len = PAGE_SIZE; + disk = 0; + if (sector_nr + (len>>9) > max_sector) + len = (max_sector - sector_nr) << 9; + if (len == 0) + break; + for (bio= biolist ; bio ; bio=bio->bi_next) { + page = bio->bi_io_vec[bio->bi_vcnt].bv_page; + if (bio_add_page(bio, page, len, 0) == 0) { + /* stop here */ + struct bio *bio2; + bio->bi_io_vec[bio->bi_vcnt].bv_page = page; + for (bio2 = biolist; bio2 && bio2 != bio; bio2 = bio2->bi_next) { + /* remove last page from this bio */ + bio2->bi_vcnt--; + bio2->bi_size -= len; + bio2->bi_flags &= ~(1<< BIO_SEG_VALID); + } + goto bio_full; + } + disk = i; + } + nr_sectors += len>>9; + sector_nr += len>>9; + } while (biolist->bi_vcnt < RESYNC_PAGES); + bio_full: + r10_bio->sectors = nr_sectors; + + while (biolist) { + bio = biolist; + biolist = biolist->bi_next; + + bio->bi_next = NULL; + r10_bio = bio->bi_private; + r10_bio->sectors = nr_sectors; + + if (bio->bi_end_io == end_sync_read) { + md_sync_acct(bio->bi_bdev, nr_sectors); + generic_make_request(bio); + } + } + + return sectors_skipped + nr_sectors; + giveup: + /* There is nowhere to write, so all non-sync + * drives must be failed, so try the next chunk... + */ + { + int sec = max_sector - sector_nr; + sectors_skipped += sec; + chunks_skipped ++; + sector_nr = max_sector; + md_done_sync(mddev, sec, 1); + goto skipped; + } +} + +static int run(mddev_t *mddev) +{ + conf_t *conf; + int i, disk_idx; + mirror_info_t *disk; + mdk_rdev_t *rdev; + struct list_head *tmp; + int nc, fc; + sector_t stride, size; + + if (mddev->level != 10) { + printk(KERN_ERR "raid10: %s: raid level not set correctly... (%d)\n", + mdname(mddev), mddev->level); + goto out; + } + nc = mddev->layout & 255; + fc = (mddev->layout >> 8) & 255; + if ((nc*fc) <2 || (nc*fc) > mddev->raid_disks || + (mddev->layout >> 16)) { + printk(KERN_ERR "raid10: %s: unsupported raid10 layout: 0x%8x\n", + mdname(mddev), mddev->layout); + goto out; + } + /* + * copy the already verified devices into our private RAID10 + * bookkeeping area. [whatever we allocate in run(), + * should be freed in stop()] + */ + conf = kmalloc(sizeof(conf_t), GFP_KERNEL); + mddev->private = conf; + if (!conf) { + printk(KERN_ERR "raid10: couldn't allocate memory for %s\n", + mdname(mddev)); + goto out; + } + memset(conf, 0, sizeof(*conf)); + conf->mirrors = kmalloc(sizeof(struct mirror_info)*mddev->raid_disks, + GFP_KERNEL); + if (!conf->mirrors) { + printk(KERN_ERR "raid10: couldn't allocate memory for %s\n", + mdname(mddev)); + goto out_free_conf; + } + memset(conf->mirrors, 0, sizeof(struct mirror_info)*mddev->raid_disks); + + conf->near_copies = nc; + conf->far_copies = fc; + conf->copies = nc*fc; + conf->chunk_mask = (sector_t)(mddev->chunk_size>>9)-1; + conf->chunk_shift = ffz(~mddev->chunk_size) - 9; + stride = mddev->size >> (conf->chunk_shift-1); + sector_div(stride, fc); + conf->stride = stride << conf->chunk_shift; + + conf->r10bio_pool = mempool_create(NR_RAID10_BIOS, r10bio_pool_alloc, + r10bio_pool_free, conf); + if (!conf->r10bio_pool) { + printk(KERN_ERR "raid10: couldn't allocate memory for %s\n", + mdname(mddev)); + goto out_free_conf; + } + mddev->queue->unplug_fn = raid10_unplug; + + mddev->queue->issue_flush_fn = raid10_issue_flush; + + ITERATE_RDEV(mddev, rdev, tmp) { + disk_idx = rdev->raid_disk; + if (disk_idx >= mddev->raid_disks + || disk_idx < 0) + continue; + disk = conf->mirrors + disk_idx; + + disk->rdev = rdev; + + blk_queue_stack_limits(mddev->queue, + rdev->bdev->bd_disk->queue); + /* as we don't honour merge_bvec_fn, we must never risk + * violating it, so limit ->max_sector to one PAGE, as + * a one page request is never in violation. + */ + if (rdev->bdev->bd_disk->queue->merge_bvec_fn && + mddev->queue->max_sectors > (PAGE_SIZE>>9)) + mddev->queue->max_sectors = (PAGE_SIZE>>9); + + disk->head_position = 0; + if (!rdev->faulty && rdev->in_sync) + conf->working_disks++; + } + conf->raid_disks = mddev->raid_disks; + conf->mddev = mddev; + spin_lock_init(&conf->device_lock); + INIT_LIST_HEAD(&conf->retry_list); + + spin_lock_init(&conf->resync_lock); + init_waitqueue_head(&conf->wait_idle); + init_waitqueue_head(&conf->wait_resume); + + if (!conf->working_disks) { + printk(KERN_ERR "raid10: no operational mirrors for %s\n", + mdname(mddev)); + goto out_free_conf; + } + + mddev->degraded = 0; + for (i = 0; i < conf->raid_disks; i++) { + + disk = conf->mirrors + i; + + if (!disk->rdev) { + disk->head_position = 0; + mddev->degraded++; + } + } + + + mddev->thread = md_register_thread(raid10d, mddev, "%s_raid10"); + if (!mddev->thread) { + printk(KERN_ERR + "raid10: couldn't allocate thread for %s\n", + mdname(mddev)); + goto out_free_conf; + } + + printk(KERN_INFO + "raid10: raid set %s active with %d out of %d devices\n", + mdname(mddev), mddev->raid_disks - mddev->degraded, + mddev->raid_disks); + /* + * Ok, everything is just fine now + */ + size = conf->stride * conf->raid_disks; + sector_div(size, conf->near_copies); + mddev->array_size = size/2; + mddev->resync_max_sectors = size; + + /* Calculate max read-ahead size. + * We need to readahead at least twice a whole stripe.... + * maybe... + */ + { + int stripe = conf->raid_disks * mddev->chunk_size / PAGE_CACHE_SIZE; + stripe /= conf->near_copies; + if (mddev->queue->backing_dev_info.ra_pages < 2* stripe) + mddev->queue->backing_dev_info.ra_pages = 2* stripe; + } + + if (conf->near_copies < mddev->raid_disks) + blk_queue_merge_bvec(mddev->queue, raid10_mergeable_bvec); + return 0; + +out_free_conf: + if (conf->r10bio_pool) + mempool_destroy(conf->r10bio_pool); + if (conf->mirrors) + kfree(conf->mirrors); + kfree(conf); + mddev->private = NULL; +out: + return -EIO; +} + +static int stop(mddev_t *mddev) +{ + conf_t *conf = mddev_to_conf(mddev); + + md_unregister_thread(mddev->thread); + mddev->thread = NULL; + blk_sync_queue(mddev->queue); /* the unplug fn references 'conf'*/ + if (conf->r10bio_pool) + mempool_destroy(conf->r10bio_pool); + if (conf->mirrors) + kfree(conf->mirrors); + kfree(conf); + mddev->private = NULL; + return 0; +} + + +static mdk_personality_t raid10_personality = +{ + .name = "raid10", + .owner = THIS_MODULE, + .make_request = make_request, + .run = run, + .stop = stop, + .status = status, + .error_handler = error, + .hot_add_disk = raid10_add_disk, + .hot_remove_disk= raid10_remove_disk, + .spare_active = raid10_spare_active, + .sync_request = sync_request, +}; + +static int __init raid_init(void) +{ + return register_md_personality(RAID10, &raid10_personality); +} + +static void raid_exit(void) +{ + unregister_md_personality(RAID10); +} + +module_init(raid_init); +module_exit(raid_exit); +MODULE_LICENSE("GPL"); +MODULE_ALIAS("md-personality-9"); /* RAID10 */ |
