diff options
Diffstat (limited to 'drivers/md/raid1.c')
| -rw-r--r-- | drivers/md/raid1.c | 1449 |
1 files changed, 1449 insertions, 0 deletions
diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c new file mode 100644 index 000000000000..a389394b52f6 --- /dev/null +++ b/drivers/md/raid1.c @@ -0,0 +1,1449 @@ +/* + * raid1.c : Multiple Devices driver for Linux + * + * Copyright (C) 1999, 2000, 2001 Ingo Molnar, Red Hat + * + * Copyright (C) 1996, 1997, 1998 Ingo Molnar, Miguel de Icaza, Gadi Oxman + * + * RAID-1 management functions. + * + * Better read-balancing code written by Mika Kuoppala <miku@iki.fi>, 2000 + * + * Fixes to reconstruction by Jakob Østergaard" <jakob@ostenfeld.dk> + * Various fixes by Neil Brown <neilb@cse.unsw.edu.au> + * + * 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/raid1.h> + +/* + * Number of guaranteed r1bios in case of extreme VM load: + */ +#define NR_RAID1_BIOS 256 + +static mdk_personality_t raid1_personality; + +static void unplug_slaves(mddev_t *mddev); + + +static void * r1bio_pool_alloc(unsigned int __nocast gfp_flags, void *data) +{ + struct pool_info *pi = data; + r1bio_t *r1_bio; + int size = offsetof(r1bio_t, bios[pi->raid_disks]); + + /* allocate a r1bio with room for raid_disks entries in the bios array */ + r1_bio = kmalloc(size, gfp_flags); + if (r1_bio) + memset(r1_bio, 0, size); + else + unplug_slaves(pi->mddev); + + return r1_bio; +} + +static void r1bio_pool_free(void *r1_bio, void *data) +{ + kfree(r1_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) + +static void * r1buf_pool_alloc(unsigned int __nocast gfp_flags, void *data) +{ + struct pool_info *pi = data; + struct page *page; + r1bio_t *r1_bio; + struct bio *bio; + int i, j; + + r1_bio = r1bio_pool_alloc(gfp_flags, pi); + if (!r1_bio) { + unplug_slaves(pi->mddev); + return NULL; + } + + /* + * Allocate bios : 1 for reading, n-1 for writing + */ + for (j = pi->raid_disks ; j-- ; ) { + bio = bio_alloc(gfp_flags, RESYNC_PAGES); + if (!bio) + goto out_free_bio; + r1_bio->bios[j] = bio; + } + /* + * Allocate RESYNC_PAGES data pages and attach them to + * the first bio; + */ + bio = r1_bio->bios[0]; + 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; + } + + r1_bio->master_bio = NULL; + + return r1_bio; + +out_free_pages: + for ( ; i > 0 ; i--) + __free_page(bio->bi_io_vec[i-1].bv_page); +out_free_bio: + while ( ++j < pi->raid_disks ) + bio_put(r1_bio->bios[j]); + r1bio_pool_free(r1_bio, data); + return NULL; +} + +static void r1buf_pool_free(void *__r1_bio, void *data) +{ + struct pool_info *pi = data; + int i; + r1bio_t *r1bio = __r1_bio; + struct bio *bio = r1bio->bios[0]; + + for (i = 0; i < RESYNC_PAGES; i++) { + __free_page(bio->bi_io_vec[i].bv_page); + bio->bi_io_vec[i].bv_page = NULL; + } + for (i=0 ; i < pi->raid_disks; i++) + bio_put(r1bio->bios[i]); + + r1bio_pool_free(r1bio, data); +} + +static void put_all_bios(conf_t *conf, r1bio_t *r1_bio) +{ + int i; + + for (i = 0; i < conf->raid_disks; i++) { + struct bio **bio = r1_bio->bios + i; + if (*bio) + bio_put(*bio); + *bio = NULL; + } +} + +static inline void free_r1bio(r1bio_t *r1_bio) +{ + unsigned long flags; + + conf_t *conf = mddev_to_conf(r1_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, r1_bio); + mempool_free(r1_bio, conf->r1bio_pool); +} + +static inline void put_buf(r1bio_t *r1_bio) +{ + conf_t *conf = mddev_to_conf(r1_bio->mddev); + unsigned long flags; + + mempool_free(r1_bio, conf->r1buf_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(r1bio_t *r1_bio) +{ + unsigned long flags; + mddev_t *mddev = r1_bio->mddev; + conf_t *conf = mddev_to_conf(mddev); + + spin_lock_irqsave(&conf->device_lock, flags); + list_add(&r1_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(r1bio_t *r1_bio) +{ + struct bio *bio = r1_bio->master_bio; + + bio_endio(bio, bio->bi_size, + test_bit(R1BIO_Uptodate, &r1_bio->state) ? 0 : -EIO); + free_r1bio(r1_bio); +} + +/* + * Update disk head position estimator based on IRQ completion info. + */ +static inline void update_head_pos(int disk, r1bio_t *r1_bio) +{ + conf_t *conf = mddev_to_conf(r1_bio->mddev); + + conf->mirrors[disk].head_position = + r1_bio->sector + (r1_bio->sectors); +} + +static int raid1_end_read_request(struct bio *bio, unsigned int bytes_done, int error) +{ + int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags); + r1bio_t * r1_bio = (r1bio_t *)(bio->bi_private); + int mirror; + conf_t *conf = mddev_to_conf(r1_bio->mddev); + + if (bio->bi_size) + return 1; + + mirror = r1_bio->read_disk; + /* + * this branch is our 'one mirror IO has finished' event handler: + */ + if (!uptodate) + md_error(r1_bio->mddev, conf->mirrors[mirror].rdev); + else + /* + * Set R1BIO_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(R1BIO_Uptodate, &r1_bio->state); + + update_head_pos(mirror, r1_bio); + + /* + * we have only one bio on the read side + */ + if (uptodate) + raid_end_bio_io(r1_bio); + else { + /* + * oops, read error: + */ + char b[BDEVNAME_SIZE]; + if (printk_ratelimit()) + printk(KERN_ERR "raid1: %s: rescheduling sector %llu\n", + bdevname(conf->mirrors[mirror].rdev->bdev,b), (unsigned long long)r1_bio->sector); + reschedule_retry(r1_bio); + } + + rdev_dec_pending(conf->mirrors[mirror].rdev, conf->mddev); + return 0; +} + +static int raid1_end_write_request(struct bio *bio, unsigned int bytes_done, int error) +{ + int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags); + r1bio_t * r1_bio = (r1bio_t *)(bio->bi_private); + int mirror; + conf_t *conf = mddev_to_conf(r1_bio->mddev); + + if (bio->bi_size) + return 1; + + for (mirror = 0; mirror < conf->raid_disks; mirror++) + if (r1_bio->bios[mirror] == bio) + break; + + /* + * this branch is our 'one mirror IO has finished' event handler: + */ + if (!uptodate) + md_error(r1_bio->mddev, conf->mirrors[mirror].rdev); + else + /* + * Set R1BIO_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(R1BIO_Uptodate, &r1_bio->state); + + update_head_pos(mirror, r1_bio); + + /* + * + * Let's see if all mirrored write operations have finished + * already. + */ + if (atomic_dec_and_test(&r1_bio->remaining)) { + md_write_end(r1_bio->mddev); + raid_end_bio_io(r1_bio); + } + + rdev_dec_pending(conf->mirrors[mirror].rdev, conf->mddev); + return 0; +} + + +/* + * 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. + */ +static int read_balance(conf_t *conf, r1bio_t *r1_bio) +{ + const unsigned long this_sector = r1_bio->sector; + int new_disk = conf->last_used, disk = new_disk; + const int sectors = r1_bio->sectors; + sector_t new_distance, current_distance; + mdk_rdev_t *new_rdev, *rdev; + + rcu_read_lock(); + /* + * Check if it 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. + */ + retry: + if (conf->mddev->recovery_cp < MaxSector && + (this_sector + sectors >= conf->next_resync)) { + /* Choose the first operation device, for consistancy */ + new_disk = 0; + + while ((new_rdev=conf->mirrors[new_disk].rdev) == NULL || + !new_rdev->in_sync) { + new_disk++; + if (new_disk == conf->raid_disks) { + new_disk = -1; + break; + } + } + goto rb_out; + } + + + /* make sure the disk is operational */ + while ((new_rdev=conf->mirrors[new_disk].rdev) == NULL || + !new_rdev->in_sync) { + if (new_disk <= 0) + new_disk = conf->raid_disks; + new_disk--; + if (new_disk == disk) { + new_disk = -1; + goto rb_out; + } + } + disk = new_disk; + /* now disk == new_disk == starting point for search */ + + /* + * Don't change to another disk for sequential reads: + */ + if (conf->next_seq_sect == this_sector) + goto rb_out; + if (this_sector == conf->mirrors[new_disk].head_position) + goto rb_out; + + current_distance = abs(this_sector - conf->mirrors[disk].head_position); + + /* Find the disk whose head is closest */ + + do { + if (disk <= 0) + disk = conf->raid_disks; + disk--; + + if ((rdev=conf->mirrors[disk].rdev) == NULL || + !rdev->in_sync) + continue; + + if (!atomic_read(&rdev->nr_pending)) { + new_disk = disk; + new_rdev = rdev; + break; + } + new_distance = abs(this_sector - conf->mirrors[disk].head_position); + if (new_distance < current_distance) { + current_distance = new_distance; + new_disk = disk; + new_rdev = rdev; + } + } while (disk != conf->last_used); + +rb_out: + + + if (new_disk >= 0) { + conf->next_seq_sect = this_sector + sectors; + conf->last_used = new_disk; + atomic_inc(&new_rdev->nr_pending); + if (!new_rdev->in_sync) { + /* cannot risk returning a device that failed + * before we inc'ed nr_pending + */ + atomic_dec(&new_rdev->nr_pending); + goto retry; + } + } + rcu_read_unlock(); + + return new_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 raid1_unplug(request_queue_t *q) +{ + unplug_slaves(q->queuedata); +} + +static int raid1_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; + r1bio_t *r1_bio; + struct bio *read_bio; + int i, disks; + mdk_rdev_t *rdev; + + /* + * 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)); + } + + /* + * make_request() can abort the operation when READA 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->bi_size >> 9; + + r1_bio->mddev = mddev; + r1_bio->sector = bio->bi_sector; + + r1_bio->state = 0; + + if (bio_data_dir(bio) == READ) { + /* + * read balancing logic: + */ + int rdisk = read_balance(conf, r1_bio); + + if (rdisk < 0) { + /* couldn't find anywhere to read from */ + raid_end_bio_io(r1_bio); + return 0; + } + mirror = conf->mirrors + rdisk; + + r1_bio->read_disk = rdisk; + + read_bio = bio_clone(bio, GFP_NOIO); + + r1_bio->bios[rdisk] = read_bio; + + read_bio->bi_sector = r1_bio->sector + mirror->rdev->data_offset; + read_bio->bi_bdev = mirror->rdev->bdev; + read_bio->bi_end_io = raid1_end_read_request; + read_bio->bi_rw = READ; + read_bio->bi_private = r1_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 + */ + disks = conf->raid_disks; + rcu_read_lock(); + for (i = 0; i < disks; i++) { + if ((rdev=conf->mirrors[i].rdev) != NULL && + !rdev->faulty) { + atomic_inc(&rdev->nr_pending); + if (rdev->faulty) { + atomic_dec(&rdev->nr_pending); + r1_bio->bios[i] = NULL; + } else + r1_bio->bios[i] = bio; + } else + r1_bio->bios[i] = NULL; + } + rcu_read_unlock(); + + atomic_set(&r1_bio->remaining, 1); + md_write_start(mddev); + for (i = 0; i < disks; i++) { + struct bio *mbio; + if (!r1_bio->bios[i]) + continue; + + mbio = bio_clone(bio, GFP_NOIO); + r1_bio->bios[i] = mbio; + + mbio->bi_sector = r1_bio->sector + conf->mirrors[i].rdev->data_offset; + mbio->bi_bdev = conf->mirrors[i].rdev->bdev; + mbio->bi_end_io = raid1_end_write_request; + mbio->bi_rw = WRITE; + mbio->bi_private = r1_bio; + + atomic_inc(&r1_bio->remaining); + generic_make_request(mbio); + } + + if (atomic_dec_and_test(&r1_bio->remaining)) { + md_write_end(mddev); + raid_end_bio_io(r1_bio); + } + + return 0; +} + +static void status(struct seq_file *seq, mddev_t *mddev) +{ + conf_t *conf = mddev_to_conf(mddev); + int i; + + 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, act as though we were just a + * normal single drive + */ + 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 "raid1: 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("RAID1 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->r1buf_pool); + conf->r1buf_pool = NULL; +} + +static int raid1_spare_active(mddev_t *mddev) +{ + int i; + conf_t *conf = mddev->private; + mirror_info_t *tmp; + + /* + * Find all failed disks within the RAID1 configuration + * and mark them readable + */ + 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 raid1_add_disk(mddev_t *mddev, mdk_rdev_t *rdev) +{ + conf_t *conf = mddev->private; + int found = 0; + int mirror; + mirror_info_t *p; + + 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)) + blk_queue_max_sectors(mddev->queue, PAGE_SIZE>>9); + + p->head_position = 0; + rdev->raid_disk = mirror; + found = 1; + p->rdev = rdev; + break; + } + + print_conf(conf); + return found; +} + +static int raid1_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); + r1bio_t * r1_bio = (r1bio_t *)(bio->bi_private); + conf_t *conf = mddev_to_conf(r1_bio->mddev); + + if (bio->bi_size) + return 1; + + if (r1_bio->bios[r1_bio->read_disk] != bio) + BUG(); + update_head_pos(r1_bio->read_disk, r1_bio); + /* + * we have read a block, now it needs to be re-written, + * or re-read if the read failed. + * We don't do much here, just schedule handling by raid1d + */ + if (!uptodate) + md_error(r1_bio->mddev, + conf->mirrors[r1_bio->read_disk].rdev); + else + set_bit(R1BIO_Uptodate, &r1_bio->state); + rdev_dec_pending(conf->mirrors[r1_bio->read_disk].rdev, conf->mddev); + reschedule_retry(r1_bio); + 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); + r1bio_t * r1_bio = (r1bio_t *)(bio->bi_private); + mddev_t *mddev = r1_bio->mddev; + conf_t *conf = mddev_to_conf(mddev); + int i; + int mirror=0; + + if (bio->bi_size) + return 1; + + for (i = 0; i < conf->raid_disks; i++) + if (r1_bio->bios[i] == bio) { + mirror = i; + break; + } + if (!uptodate) + md_error(mddev, conf->mirrors[mirror].rdev); + update_head_pos(mirror, r1_bio); + + if (atomic_dec_and_test(&r1_bio->remaining)) { + md_done_sync(mddev, r1_bio->sectors, uptodate); + put_buf(r1_bio); + } + rdev_dec_pending(conf->mirrors[mirror].rdev, mddev); + return 0; +} + +static void sync_request_write(mddev_t *mddev, r1bio_t *r1_bio) +{ + conf_t *conf = mddev_to_conf(mddev); + int i; + int disks = conf->raid_disks; + struct bio *bio, *wbio; + + bio = r1_bio->bios[r1_bio->read_disk]; + + /* + * schedule writes + */ + if (!test_bit(R1BIO_Uptodate, &r1_bio->state)) { + /* + * There is no point trying a read-for-reconstruct as + * reconstruct is about to be aborted + */ + char b[BDEVNAME_SIZE]; + printk(KERN_ALERT "raid1: %s: unrecoverable I/O read error" + " for block %llu\n", + bdevname(bio->bi_bdev,b), + (unsigned long long)r1_bio->sector); + md_done_sync(mddev, r1_bio->sectors, 0); + put_buf(r1_bio); + return; + } + + atomic_set(&r1_bio->remaining, 1); + for (i = 0; i < disks ; i++) { + wbio = r1_bio->bios[i]; + if (wbio->bi_end_io != end_sync_write) + continue; + + atomic_inc(&conf->mirrors[i].rdev->nr_pending); + atomic_inc(&r1_bio->remaining); + md_sync_acct(conf->mirrors[i].rdev->bdev, wbio->bi_size >> 9); + generic_make_request(wbio); + } + + if (atomic_dec_and_test(&r1_bio->remaining)) { + md_done_sync(mddev, r1_bio->sectors, 1); + put_buf(r1_bio); + } +} + +/* + * 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 raid1d(mddev_t *mddev) +{ + r1bio_t *r1_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; + r1_bio = list_entry(head->prev, r1bio_t, retry_list); + list_del(head->prev); + spin_unlock_irqrestore(&conf->device_lock, flags); + + mddev = r1_bio->mddev; + conf = mddev_to_conf(mddev); + if (test_bit(R1BIO_IsSync, &r1_bio->state)) { + sync_request_write(mddev, r1_bio); + unplug = 1; + } else { + int disk; + bio = r1_bio->bios[r1_bio->read_disk]; + if ((disk=read_balance(conf, r1_bio)) == -1) { + printk(KERN_ALERT "raid1: %s: unrecoverable I/O" + " read error for block %llu\n", + bdevname(bio->bi_bdev,b), + (unsigned long long)r1_bio->sector); + raid_end_bio_io(r1_bio); + } else { + r1_bio->bios[r1_bio->read_disk] = NULL; + r1_bio->read_disk = disk; + bio_put(bio); + bio = bio_clone(r1_bio->master_bio, GFP_NOIO); + r1_bio->bios[r1_bio->read_disk] = bio; + rdev = conf->mirrors[disk].rdev; + if (printk_ratelimit()) + printk(KERN_ERR "raid1: %s: redirecting sector %llu to" + " another mirror\n", + bdevname(rdev->bdev,b), + (unsigned long long)r1_bio->sector); + bio->bi_sector = r1_bio->sector + rdev->data_offset; + bio->bi_bdev = rdev->bdev; + bio->bi_end_io = raid1_end_read_request; + bio->bi_rw = READ; + bio->bi_private = r1_bio; + 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->r1buf_pool) + BUG(); + conf->r1buf_pool = mempool_create(buffs, r1buf_pool_alloc, r1buf_pool_free, + conf->poolinfo); + if (!conf->r1buf_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. + */ + +static int sync_request(mddev_t *mddev, sector_t sector_nr, int go_faster) +{ + conf_t *conf = mddev_to_conf(mddev); + mirror_info_t *mirror; + r1bio_t *r1_bio; + struct bio *bio; + sector_t max_sector, nr_sectors; + int disk; + int i; + int write_targets = 0; + + if (!conf->r1buf_pool) + if (init_resync(conf)) + return -ENOMEM; + + max_sector = mddev->size << 1; + if (sector_nr >= max_sector) { + close_sync(conf); + return 0; + } + + /* + * 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); + + /* + * If reconstructing, and >1 working disc, + * could dedicate one to rebuild and others to + * service read requests .. + */ + disk = conf->last_used; + /* make sure disk is operational */ + + while (conf->mirrors[disk].rdev == NULL || + !conf->mirrors[disk].rdev->in_sync) { + if (disk <= 0) + disk = conf->raid_disks; + disk--; + if (disk == conf->last_used) + break; + } + conf->last_used = disk; + atomic_inc(&conf->mirrors[disk].rdev->nr_pending); + + + mirror = conf->mirrors + disk; + + r1_bio = mempool_alloc(conf->r1buf_pool, GFP_NOIO); + + spin_lock_irq(&conf->resync_lock); + conf->nr_pending++; + spin_unlock_irq(&conf->resync_lock); + + r1_bio->mddev = mddev; + r1_bio->sector = sector_nr; + set_bit(R1BIO_IsSync, &r1_bio->state); + r1_bio->read_disk = disk; + + for (i=0; i < conf->raid_disks; i++) { + bio = r1_bio->bios[i]; + + /* take from bio_init */ + bio->bi_next = NULL; + bio->bi_flags |= 1 << BIO_UPTODATE; + bio->bi_rw = 0; + bio->bi_vcnt = 0; + bio->bi_idx = 0; + bio->bi_phys_segments = 0; + bio->bi_hw_segments = 0; + bio->bi_size = 0; + bio->bi_end_io = NULL; + bio->bi_private = NULL; + + if (i == disk) { + bio->bi_rw = READ; + bio->bi_end_io = end_sync_read; + } else if (conf->mirrors[i].rdev && + !conf->mirrors[i].rdev->faulty && + (!conf->mirrors[i].rdev->in_sync || + sector_nr + RESYNC_SECTORS > mddev->recovery_cp)) { + bio->bi_rw = WRITE; + bio->bi_end_io = end_sync_write; + write_targets ++; + } else + continue; + bio->bi_sector = sector_nr + conf->mirrors[i].rdev->data_offset; + bio->bi_bdev = conf->mirrors[i].rdev->bdev; + bio->bi_private = r1_bio; + } + if (write_targets == 0) { + /* There is nowhere to write, so all non-sync + * drives must be failed - so we are finished + */ + int rv = max_sector - sector_nr; + md_done_sync(mddev, rv, 1); + put_buf(r1_bio); + rdev_dec_pending(conf->mirrors[disk].rdev, mddev); + return rv; + } + + nr_sectors = 0; + do { + struct page *page; + int len = PAGE_SIZE; + if (sector_nr + (len>>9) > max_sector) + len = (max_sector - sector_nr) << 9; + if (len == 0) + break; + for (i=0 ; i < conf->raid_disks; i++) { + bio = r1_bio->bios[i]; + if (bio->bi_end_io) { + page = r1_bio->bios[0]->bi_io_vec[bio->bi_vcnt].bv_page; + if (bio_add_page(bio, page, len, 0) == 0) { + /* stop here */ + r1_bio->bios[0]->bi_io_vec[bio->bi_vcnt].bv_page = page; + while (i > 0) { + i--; + bio = r1_bio->bios[i]; + if (bio->bi_end_io==NULL) continue; + /* remove last page from this bio */ + bio->bi_vcnt--; + bio->bi_size -= len; + bio->bi_flags &= ~(1<< BIO_SEG_VALID); + } + goto bio_full; + } + } + } + nr_sectors += len>>9; + sector_nr += len>>9; + } while (r1_bio->bios[disk]->bi_vcnt < RESYNC_PAGES); + bio_full: + bio = r1_bio->bios[disk]; + r1_bio->sectors = nr_sectors; + + md_sync_acct(mirror->rdev->bdev, nr_sectors); + + generic_make_request(bio); + + return nr_sectors; +} + +static int run(mddev_t *mddev) +{ + conf_t *conf; + int i, j, disk_idx; + mirror_info_t *disk; + mdk_rdev_t *rdev; + struct list_head *tmp; + + if (mddev->level != 1) { + printk("raid1: %s: raid level not set to mirroring (%d)\n", + mdname(mddev), mddev->level); + goto out; + } + /* + * copy the already verified devices into our private RAID1 + * bookkeeping area. [whatever we allocate in run(), + * should be freed in stop()] + */ + conf = kmalloc(sizeof(conf_t), GFP_KERNEL); + mddev->private = conf; + if (!conf) + goto out_no_mem; + + memset(conf, 0, sizeof(*conf)); + conf->mirrors = kmalloc(sizeof(struct mirror_info)*mddev->raid_disks, + GFP_KERNEL); + if (!conf->mirrors) + goto out_no_mem; + + memset(conf->mirrors, 0, sizeof(struct mirror_info)*mddev->raid_disks); + + conf->poolinfo = kmalloc(sizeof(*conf->poolinfo), GFP_KERNEL); + if (!conf->poolinfo) + goto out_no_mem; + conf->poolinfo->mddev = mddev; + conf->poolinfo->raid_disks = mddev->raid_disks; + conf->r1bio_pool = mempool_create(NR_RAID1_BIOS, r1bio_pool_alloc, + r1bio_pool_free, + conf->poolinfo); + if (!conf->r1bio_pool) + goto out_no_mem; + + mddev->queue->unplug_fn = raid1_unplug; + + mddev->queue->issue_flush_fn = raid1_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)) + blk_queue_max_sectors(mddev->queue, 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); + if (conf->working_disks == 1) + mddev->recovery_cp = MaxSector; + + 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 "raid1: 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++; + } + } + + /* + * find the first working one and use it as a starting point + * to read balancing. + */ + for (j = 0; j < conf->raid_disks && + (!conf->mirrors[j].rdev || + !conf->mirrors[j].rdev->in_sync) ; j++) + /* nothing */; + conf->last_used = j; + + + + { + mddev->thread = md_register_thread(raid1d, mddev, "%s_raid1"); + if (!mddev->thread) { + printk(KERN_ERR + "raid1: couldn't allocate thread for %s\n", + mdname(mddev)); + goto out_free_conf; + } + } + printk(KERN_INFO + "raid1: raid set %s active with %d out of %d mirrors\n", + mdname(mddev), mddev->raid_disks - mddev->degraded, + mddev->raid_disks); + /* + * Ok, everything is just fine now + */ + mddev->array_size = mddev->size; + + return 0; + +out_no_mem: + printk(KERN_ERR "raid1: couldn't allocate memory for %s\n", + mdname(mddev)); + +out_free_conf: + if (conf) { + if (conf->r1bio_pool) + mempool_destroy(conf->r1bio_pool); + if (conf->mirrors) + kfree(conf->mirrors); + if (conf->poolinfo) + kfree(conf->poolinfo); + 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->r1bio_pool) + mempool_destroy(conf->r1bio_pool); + if (conf->mirrors) + kfree(conf->mirrors); + if (conf->poolinfo) + kfree(conf->poolinfo); + kfree(conf); + mddev->private = NULL; + return 0; +} + +static int raid1_resize(mddev_t *mddev, sector_t sectors) +{ + /* no resync is happening, and there is enough space + * on all devices, so we can resize. + * We need to make sure resync covers any new space. + * If the array is shrinking we should possibly wait until + * any io in the removed space completes, but it hardly seems + * worth it. + */ + mddev->array_size = sectors>>1; + set_capacity(mddev->gendisk, mddev->array_size << 1); + mddev->changed = 1; + if (mddev->array_size > mddev->size && mddev->recovery_cp == MaxSector) { + mddev->recovery_cp = mddev->size << 1; + set_bit(MD_RECOVERY_NEEDED, &mddev->recovery); + } + mddev->size = mddev->array_size; + return 0; +} + +static int raid1_reshape(mddev_t *mddev, int raid_disks) +{ + /* We need to: + * 1/ resize the r1bio_pool + * 2/ resize conf->mirrors + * + * We allocate a new r1bio_pool if we can. + * Then raise a device barrier and wait until all IO stops. + * Then resize conf->mirrors and swap in the new r1bio pool. + */ + mempool_t *newpool, *oldpool; + struct pool_info *newpoolinfo; + mirror_info_t *newmirrors; + conf_t *conf = mddev_to_conf(mddev); + + int d; + + for (d= raid_disks; d < conf->raid_disks; d++) + if (conf->mirrors[d].rdev) + return -EBUSY; + + newpoolinfo = kmalloc(sizeof(*newpoolinfo), GFP_KERNEL); + if (!newpoolinfo) + return -ENOMEM; + newpoolinfo->mddev = mddev; + newpoolinfo->raid_disks = raid_disks; + + newpool = mempool_create(NR_RAID1_BIOS, r1bio_pool_alloc, + r1bio_pool_free, newpoolinfo); + if (!newpool) { + kfree(newpoolinfo); + return -ENOMEM; + } + newmirrors = kmalloc(sizeof(struct mirror_info) * raid_disks, GFP_KERNEL); + if (!newmirrors) { + kfree(newpoolinfo); + mempool_destroy(newpool); + return -ENOMEM; + } + memset(newmirrors, 0, sizeof(struct mirror_info)*raid_disks); + + spin_lock_irq(&conf->resync_lock); + conf->barrier++; + wait_event_lock_irq(conf->wait_idle, !conf->nr_pending, + conf->resync_lock, unplug_slaves(mddev)); + spin_unlock_irq(&conf->resync_lock); + + /* ok, everything is stopped */ + oldpool = conf->r1bio_pool; + conf->r1bio_pool = newpool; + for (d=0; d < raid_disks && d < conf->raid_disks; d++) + newmirrors[d] = conf->mirrors[d]; + kfree(conf->mirrors); + conf->mirrors = newmirrors; + kfree(conf->poolinfo); + conf->poolinfo = newpoolinfo; + + mddev->degraded += (raid_disks - conf->raid_disks); + conf->raid_disks = mddev->raid_disks = raid_disks; + + spin_lock_irq(&conf->resync_lock); + conf->barrier--; + spin_unlock_irq(&conf->resync_lock); + wake_up(&conf->wait_resume); + wake_up(&conf->wait_idle); + + + set_bit(MD_RECOVERY_NEEDED, &mddev->recovery); + md_wakeup_thread(mddev->thread); + + mempool_destroy(oldpool); + return 0; +} + + +static mdk_personality_t raid1_personality = +{ + .name = "raid1", + .owner = THIS_MODULE, + .make_request = make_request, + .run = run, + .stop = stop, + .status = status, + .error_handler = error, + .hot_add_disk = raid1_add_disk, + .hot_remove_disk= raid1_remove_disk, + .spare_active = raid1_spare_active, + .sync_request = sync_request, + .resize = raid1_resize, + .reshape = raid1_reshape, +}; + +static int __init raid_init(void) +{ + return register_md_personality(RAID1, &raid1_personality); +} + +static void raid_exit(void) +{ + unregister_md_personality(RAID1); +} + +module_init(raid_init); +module_exit(raid_exit); +MODULE_LICENSE("GPL"); +MODULE_ALIAS("md-personality-3"); /* RAID1 */ |