diff options
Diffstat (limited to 'drivers/md/raid1.c')
| -rw-r--r-- | drivers/md/raid1.c | 2278 |
1 files changed, 2278 insertions, 0 deletions
diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c new file mode 100644 index 00000000..36f1ed31 --- /dev/null +++ b/drivers/md/raid1.c @@ -0,0 +1,2278 @@ +/* + * 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> + * + * Changes by Peter T. Breuer <ptb@it.uc3m.es> 31/1/2003 to support + * bitmapped intelligence in resync: + * + * - bitmap marked during normal i/o + * - bitmap used to skip nondirty blocks during sync + * + * Additions to bitmap code, (C) 2003-2004 Paul Clements, SteelEye Technology: + * - persistent bitmap code + * + * 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/slab.h> +#include <linux/delay.h> +#include <linux/blkdev.h> +#include <linux/seq_file.h> +#include "md.h" +#include "raid1.h" +#include "bitmap.h" + +#define DEBUG 0 +#if DEBUG +#define PRINTK(x...) printk(x) +#else +#define PRINTK(x...) +#endif + +/* + * Number of guaranteed r1bios in case of extreme VM load: + */ +#define NR_RAID1_BIOS 256 + + +static void allow_barrier(conf_t *conf); +static void lower_barrier(conf_t *conf); + +static void * r1bio_pool_alloc(gfp_t gfp_flags, void *data) +{ + struct pool_info *pi = data; + int size = offsetof(r1bio_t, bios[pi->raid_disks]); + + /* allocate a r1bio with room for raid_disks entries in the bios array */ + return kzalloc(size, gfp_flags); +} + +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(gfp_t 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) + return NULL; + + /* + * Allocate bios : 1 for reading, n-1 for writing + */ + for (j = pi->raid_disks ; j-- ; ) { + bio = bio_kmalloc(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. + * If this is a user-requested check/repair, allocate + * RESYNC_PAGES for each bio. + */ + if (test_bit(MD_RECOVERY_REQUESTED, &pi->mddev->recovery)) + j = pi->raid_disks; + else + j = 1; + while(j--) { + bio = r1_bio->bios[j]; + 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; + bio->bi_vcnt = i+1; + } + } + /* If not user-requests, copy the page pointers to all bios */ + if (!test_bit(MD_RECOVERY_REQUESTED, &pi->mddev->recovery)) { + for (i=0; i<RESYNC_PAGES ; i++) + for (j=1; j<pi->raid_disks; j++) + r1_bio->bios[j]->bi_io_vec[i].bv_page = + r1_bio->bios[0]->bi_io_vec[i].bv_page; + } + + r1_bio->master_bio = NULL; + + return r1_bio; + +out_free_pages: + for (j=0 ; j < pi->raid_disks; j++) + for (i=0; i < r1_bio->bios[j]->bi_vcnt ; i++) + put_page(r1_bio->bios[j]->bi_io_vec[i].bv_page); + j = -1; +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,j; + r1bio_t *r1bio = __r1_bio; + + for (i = 0; i < RESYNC_PAGES; i++) + for (j = pi->raid_disks; j-- ;) { + if (j == 0 || + r1bio->bios[j]->bi_io_vec[i].bv_page != + r1bio->bios[0]->bi_io_vec[i].bv_page) + safe_put_page(r1bio->bios[j]->bi_io_vec[i].bv_page); + } + 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 != IO_BLOCKED) + bio_put(*bio); + *bio = NULL; + } +} + +static void free_r1bio(r1bio_t *r1_bio) +{ + conf_t *conf = r1_bio->mddev->private; + + /* + * Wake up any possible resync thread that waits for the device + * to go idle. + */ + allow_barrier(conf); + + put_all_bios(conf, r1_bio); + mempool_free(r1_bio, conf->r1bio_pool); +} + +static void put_buf(r1bio_t *r1_bio) +{ + conf_t *conf = r1_bio->mddev->private; + int i; + + for (i=0; i<conf->raid_disks; i++) { + struct bio *bio = r1_bio->bios[i]; + if (bio->bi_end_io) + rdev_dec_pending(conf->mirrors[i].rdev, r1_bio->mddev); + } + + mempool_free(r1_bio, conf->r1buf_pool); + + lower_barrier(conf); +} + +static void reschedule_retry(r1bio_t *r1_bio) +{ + unsigned long flags; + mddev_t *mddev = r1_bio->mddev; + conf_t *conf = mddev->private; + + spin_lock_irqsave(&conf->device_lock, flags); + list_add(&r1_bio->retry_list, &conf->retry_list); + conf->nr_queued ++; + spin_unlock_irqrestore(&conf->device_lock, flags); + + wake_up(&conf->wait_barrier); + 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; + + /* if nobody has done the final endio yet, do it now */ + if (!test_and_set_bit(R1BIO_Returned, &r1_bio->state)) { + PRINTK(KERN_DEBUG "raid1: sync end %s on sectors %llu-%llu\n", + (bio_data_dir(bio) == WRITE) ? "write" : "read", + (unsigned long long) bio->bi_sector, + (unsigned long long) bio->bi_sector + + (bio->bi_size >> 9) - 1); + + bio_endio(bio, + 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 = r1_bio->mddev->private; + + conf->mirrors[disk].head_position = + r1_bio->sector + (r1_bio->sectors); +} + +static void raid1_end_read_request(struct bio *bio, int error) +{ + int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags); + r1bio_t *r1_bio = bio->bi_private; + int mirror; + conf_t *conf = r1_bio->mddev->private; + + mirror = r1_bio->read_disk; + /* + * this branch is our 'one mirror IO has finished' event handler: + */ + update_head_pos(mirror, r1_bio); + + if (uptodate) + set_bit(R1BIO_Uptodate, &r1_bio->state); + else { + /* If all other devices have failed, we want to return + * the error upwards rather than fail the last device. + * Here we redefine "uptodate" to mean "Don't want to retry" + */ + unsigned long flags; + spin_lock_irqsave(&conf->device_lock, flags); + if (r1_bio->mddev->degraded == conf->raid_disks || + (r1_bio->mddev->degraded == conf->raid_disks-1 && + !test_bit(Faulty, &conf->mirrors[mirror].rdev->flags))) + uptodate = 1; + spin_unlock_irqrestore(&conf->device_lock, flags); + } + + if (uptodate) + raid_end_bio_io(r1_bio); + else { + /* + * oops, read error: + */ + char b[BDEVNAME_SIZE]; + if (printk_ratelimit()) + printk(KERN_ERR "md/raid1:%s: %s: rescheduling sector %llu\n", + mdname(conf->mddev), + 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); +} + +static void r1_bio_write_done(r1bio_t *r1_bio) +{ + if (atomic_dec_and_test(&r1_bio->remaining)) + { + /* it really is the end of this request */ + if (test_bit(R1BIO_BehindIO, &r1_bio->state)) { + /* free extra copy of the data pages */ + int i = r1_bio->behind_page_count; + while (i--) + safe_put_page(r1_bio->behind_pages[i]); + kfree(r1_bio->behind_pages); + r1_bio->behind_pages = NULL; + } + /* clear the bitmap if all writes complete successfully */ + bitmap_endwrite(r1_bio->mddev->bitmap, r1_bio->sector, + r1_bio->sectors, + !test_bit(R1BIO_Degraded, &r1_bio->state), + test_bit(R1BIO_BehindIO, &r1_bio->state)); + md_write_end(r1_bio->mddev); + raid_end_bio_io(r1_bio); + } +} + +static void raid1_end_write_request(struct bio *bio, int error) +{ + int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags); + r1bio_t *r1_bio = bio->bi_private; + int mirror, behind = test_bit(R1BIO_BehindIO, &r1_bio->state); + conf_t *conf = r1_bio->mddev->private; + struct bio *to_put = NULL; + + + for (mirror = 0; mirror < conf->raid_disks; mirror++) + if (r1_bio->bios[mirror] == bio) + break; + + /* + * 'one mirror IO has finished' event handler: + */ + r1_bio->bios[mirror] = NULL; + to_put = bio; + if (!uptodate) { + md_error(r1_bio->mddev, conf->mirrors[mirror].rdev); + /* an I/O failed, we can't clear the bitmap */ + set_bit(R1BIO_Degraded, &r1_bio->state); + } 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); + + if (behind) { + if (test_bit(WriteMostly, &conf->mirrors[mirror].rdev->flags)) + atomic_dec(&r1_bio->behind_remaining); + + /* + * In behind mode, we ACK the master bio once the I/O + * has safely reached all non-writemostly + * disks. Setting the Returned bit ensures that this + * gets done only once -- we don't ever want to return + * -EIO here, instead we'll wait + */ + if (atomic_read(&r1_bio->behind_remaining) >= (atomic_read(&r1_bio->remaining)-1) && + test_bit(R1BIO_Uptodate, &r1_bio->state)) { + /* Maybe we can return now */ + if (!test_and_set_bit(R1BIO_Returned, &r1_bio->state)) { + struct bio *mbio = r1_bio->master_bio; + PRINTK(KERN_DEBUG "raid1: behind end write sectors %llu-%llu\n", + (unsigned long long) mbio->bi_sector, + (unsigned long long) mbio->bi_sector + + (mbio->bi_size >> 9) - 1); + bio_endio(mbio, 0); + } + } + } + rdev_dec_pending(conf->mirrors[mirror].rdev, conf->mddev); + + /* + * Let's see if all mirrored write operations have finished + * already. + */ + r1_bio_write_done(r1_bio); + + if (to_put) + bio_put(to_put); +} + + +/* + * 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 sector_t this_sector = r1_bio->sector; + const int sectors = r1_bio->sectors; + int start_disk; + int best_disk; + int i; + sector_t best_dist; + mdk_rdev_t *rdev; + int choose_first; + + 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. + */ + retry: + best_disk = -1; + best_dist = MaxSector; + if (conf->mddev->recovery_cp < MaxSector && + (this_sector + sectors >= conf->next_resync)) { + choose_first = 1; + start_disk = 0; + } else { + choose_first = 0; + start_disk = conf->last_used; + } + + for (i = 0 ; i < conf->raid_disks ; i++) { + sector_t dist; + int disk = start_disk + i; + if (disk >= conf->raid_disks) + disk -= conf->raid_disks; + + rdev = rcu_dereference(conf->mirrors[disk].rdev); + if (r1_bio->bios[disk] == IO_BLOCKED + || rdev == NULL + || test_bit(Faulty, &rdev->flags)) + continue; + if (!test_bit(In_sync, &rdev->flags) && + rdev->recovery_offset < this_sector + sectors) + continue; + if (test_bit(WriteMostly, &rdev->flags)) { + /* Don't balance among write-mostly, just + * use the first as a last resort */ + if (best_disk < 0) + best_disk = disk; + continue; + } + /* This is a reasonable device to use. It might + * even be best. + */ + dist = abs(this_sector - conf->mirrors[disk].head_position); + if (choose_first + /* Don't change to another disk for sequential reads */ + || conf->next_seq_sect == this_sector + || dist == 0 + /* If device is idle, use it */ + || atomic_read(&rdev->nr_pending) == 0) { + best_disk = disk; + break; + } + if (dist < best_dist) { + best_dist = dist; + best_disk = disk; + } + } + + if (best_disk >= 0) { + rdev = rcu_dereference(conf->mirrors[best_disk].rdev); + if (!rdev) + goto retry; + atomic_inc(&rdev->nr_pending); + if (test_bit(Faulty, &rdev->flags)) { + /* cannot risk returning a device that failed + * before we inc'ed nr_pending + */ + rdev_dec_pending(rdev, conf->mddev); + goto retry; + } + conf->next_seq_sect = this_sector + sectors; + conf->last_used = best_disk; + } + rcu_read_unlock(); + + return best_disk; +} + +int md_raid1_congested(mddev_t *mddev, int bits) +{ + conf_t *conf = mddev->private; + int i, ret = 0; + + rcu_read_lock(); + for (i = 0; i < mddev->raid_disks; i++) { + mdk_rdev_t *rdev = rcu_dereference(conf->mirrors[i].rdev); + if (rdev && !test_bit(Faulty, &rdev->flags)) { + struct request_queue *q = bdev_get_queue(rdev->bdev); + + BUG_ON(!q); + + /* Note the '|| 1' - when read_balance prefers + * non-congested targets, it can be removed + */ + if ((bits & (1<<BDI_async_congested)) || 1) + ret |= bdi_congested(&q->backing_dev_info, bits); + else + ret &= bdi_congested(&q->backing_dev_info, bits); + } + } + rcu_read_unlock(); + return ret; +} +EXPORT_SYMBOL_GPL(md_raid1_congested); + +static int raid1_congested(void *data, int bits) +{ + mddev_t *mddev = data; + + return mddev_congested(mddev, bits) || + md_raid1_congested(mddev, bits); +} + +static void flush_pending_writes(conf_t *conf) +{ + /* Any writes that have been queued but are awaiting + * bitmap updates get flushed here. + */ + spin_lock_irq(&conf->device_lock); + + if (conf->pending_bio_list.head) { + struct bio *bio; + bio = bio_list_get(&conf->pending_bio_list); + spin_unlock_irq(&conf->device_lock); + /* flush any pending bitmap writes to + * disk before proceeding w/ I/O */ + bitmap_unplug(conf->mddev->bitmap); + + while (bio) { /* submit pending writes */ + struct bio *next = bio->bi_next; + bio->bi_next = NULL; + generic_make_request(bio); + bio = next; + } + } else + spin_unlock_irq(&conf->device_lock); +} + +/* Barriers.... + * Sometimes we need to suspend IO while we do something else, + * either some resync/recovery, or reconfigure the array. + * To do this we raise a 'barrier'. + * The 'barrier' is a counter that can be raised multiple times + * to count how many activities are happening which preclude + * normal IO. + * We can only raise the barrier if there is no pending IO. + * i.e. if nr_pending == 0. + * We choose only to raise the barrier if no-one is waiting for the + * barrier to go down. This means that as soon as an IO request + * is ready, no other operations which require a barrier will start + * until the IO request has had a chance. + * + * So: regular IO calls 'wait_barrier'. When that returns there + * is no backgroup IO happening, It must arrange to call + * allow_barrier when it has finished its IO. + * backgroup IO calls must call raise_barrier. Once that returns + * there is no normal IO happeing. It must arrange to call + * lower_barrier when the particular background IO completes. + */ +#define RESYNC_DEPTH 32 + +static void raise_barrier(conf_t *conf) +{ + spin_lock_irq(&conf->resync_lock); + + /* Wait until no block IO is waiting */ + wait_event_lock_irq(conf->wait_barrier, !conf->nr_waiting, + conf->resync_lock, ); + + /* block any new IO from starting */ + conf->barrier++; + + /* Now wait for all pending IO to complete */ + wait_event_lock_irq(conf->wait_barrier, + !conf->nr_pending && conf->barrier < RESYNC_DEPTH, + conf->resync_lock, ); + + spin_unlock_irq(&conf->resync_lock); +} + +static void lower_barrier(conf_t *conf) +{ + unsigned long flags; + BUG_ON(conf->barrier <= 0); + spin_lock_irqsave(&conf->resync_lock, flags); + conf->barrier--; + spin_unlock_irqrestore(&conf->resync_lock, flags); + wake_up(&conf->wait_barrier); +} + +static void wait_barrier(conf_t *conf) +{ + spin_lock_irq(&conf->resync_lock); + if (conf->barrier) { + conf->nr_waiting++; + /* Wait for the barrier to drop. + * However if there are already pending + * requests (preventing the barrier from + * rising completely), and the + * pre-process bio queue isn't empty, + * then don't wait, as we need to empty + * that queue to get the nr_pending + * count down. + */ + wait_event_lock_irq(conf->wait_barrier, + !conf->barrier || + (conf->nr_pending && + current->bio_list && + !bio_list_empty(current->bio_list)), + conf->resync_lock, + ); + conf->nr_waiting--; + } + conf->nr_pending++; + spin_unlock_irq(&conf->resync_lock); +} + +static void allow_barrier(conf_t *conf) +{ + unsigned long flags; + spin_lock_irqsave(&conf->resync_lock, flags); + conf->nr_pending--; + spin_unlock_irqrestore(&conf->resync_lock, flags); + wake_up(&conf->wait_barrier); +} + +static void freeze_array(conf_t *conf) +{ + /* stop syncio and normal IO and wait for everything to + * go quite. + * We increment barrier and nr_waiting, and then + * wait until nr_pending match nr_queued+1 + * 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 (1) + * must match the number of pending IOs (nr_pending) before + * we continue. + */ + spin_lock_irq(&conf->resync_lock); + conf->barrier++; + conf->nr_waiting++; + wait_event_lock_irq(conf->wait_barrier, + conf->nr_pending == conf->nr_queued+1, + conf->resync_lock, + flush_pending_writes(conf)); + spin_unlock_irq(&conf->resync_lock); +} +static void unfreeze_array(conf_t *conf) +{ + /* reverse the effect of the freeze */ + spin_lock_irq(&conf->resync_lock); + conf->barrier--; + conf->nr_waiting--; + wake_up(&conf->wait_barrier); + spin_unlock_irq(&conf->resync_lock); +} + + +/* duplicate the data pages for behind I/O + */ +static void alloc_behind_pages(struct bio *bio, r1bio_t *r1_bio) +{ + int i; + struct bio_vec *bvec; + struct page **pages = kzalloc(bio->bi_vcnt * sizeof(struct page*), + GFP_NOIO); + if (unlikely(!pages)) + return; + + bio_for_each_segment(bvec, bio, i) { + pages[i] = alloc_page(GFP_NOIO); + if (unlikely(!pages[i])) + goto do_sync_io; + memcpy(kmap(pages[i]) + bvec->bv_offset, + kmap(bvec->bv_page) + bvec->bv_offset, bvec->bv_len); + kunmap(pages[i]); + kunmap(bvec->bv_page); + } + r1_bio->behind_pages = pages; + r1_bio->behind_page_count = bio->bi_vcnt; + set_bit(R1BIO_BehindIO, &r1_bio->state); + return; + +do_sync_io: + for (i = 0; i < bio->bi_vcnt; i++) + if (pages[i]) + put_page(pages[i]); + kfree(pages); + PRINTK("%dB behind alloc failed, doing sync I/O\n", bio->bi_size); +} + +static int make_request(mddev_t *mddev, struct bio * bio) +{ + conf_t *conf = mddev->private; + mirror_info_t *mirror; + r1bio_t *r1_bio; + struct bio *read_bio; + int i, targets = 0, disks; + struct bitmap *bitmap; + unsigned long flags; + const int rw = bio_data_dir(bio); + const unsigned long do_sync = (bio->bi_rw & REQ_SYNC); + const unsigned long do_flush_fua = (bio->bi_rw & (REQ_FLUSH | REQ_FUA)); + mdk_rdev_t *blocked_rdev; + int plugged; + + /* + * 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. + */ + + md_write_start(mddev, bio); /* wait on superblock update early */ + + if (bio_data_dir(bio) == WRITE && + bio->bi_sector + bio->bi_size/512 > mddev->suspend_lo && + bio->bi_sector < mddev->suspend_hi) { + /* As the suspend_* range is controlled by + * userspace, we want an interruptible + * wait. + */ + DEFINE_WAIT(w); + for (;;) { + flush_signals(current); + prepare_to_wait(&conf->wait_barrier, + &w, TASK_INTERRUPTIBLE); + if (bio->bi_sector + bio->bi_size/512 <= mddev->suspend_lo || + bio->bi_sector >= mddev->suspend_hi) + break; + schedule(); + } + finish_wait(&conf->wait_barrier, &w); + } + + wait_barrier(conf); + + bitmap = mddev->bitmap; + + /* + * 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->state = 0; + r1_bio->mddev = mddev; + r1_bio->sector = bio->bi_sector; + + if (rw == 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; + + if (test_bit(WriteMostly, &mirror->rdev->flags) && + bitmap) { + /* Reading from a write-mostly device must + * take care not to over-take any writes + * that are 'behind' + */ + wait_event(bitmap->behind_wait, + atomic_read(&bitmap->behind_writes) == 0); + } + r1_bio->read_disk = rdisk; + + read_bio = bio_clone_mddev(bio, GFP_NOIO, mddev); + + 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 | do_sync; + 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 + */ + plugged = mddev_check_plugged(mddev); + + disks = conf->raid_disks; + retry_write: + blocked_rdev = NULL; + rcu_read_lock(); + for (i = 0; i < disks; i++) { + mdk_rdev_t *rdev = rcu_dereference(conf->mirrors[i].rdev); + if (rdev && unlikely(test_bit(Blocked, &rdev->flags))) { + atomic_inc(&rdev->nr_pending); + blocked_rdev = rdev; + break; + } + if (rdev && !test_bit(Faulty, &rdev->flags)) { + atomic_inc(&rdev->nr_pending); + if (test_bit(Faulty, &rdev->flags)) { + rdev_dec_pending(rdev, mddev); + r1_bio->bios[i] = NULL; + } else { + r1_bio->bios[i] = bio; + targets++; + } + } else + r1_bio->bios[i] = NULL; + } + rcu_read_unlock(); + + if (unlikely(blocked_rdev)) { + /* Wait for this device to become unblocked */ + int j; + + for (j = 0; j < i; j++) + if (r1_bio->bios[j]) + rdev_dec_pending(conf->mirrors[j].rdev, mddev); + + allow_barrier(conf); + md_wait_for_blocked_rdev(blocked_rdev, mddev); + wait_barrier(conf); + goto retry_write; + } + + BUG_ON(targets == 0); /* we never fail the last device */ + + if (targets < conf->raid_disks) { + /* array is degraded, we will not clear the bitmap + * on I/O completion (see raid1_end_write_request) */ + set_bit(R1BIO_Degraded, &r1_bio->state); + } + + /* do behind I/O ? + * Not if there are too many, or cannot allocate memory, + * or a reader on WriteMostly is waiting for behind writes + * to flush */ + if (bitmap && + (atomic_read(&bitmap->behind_writes) + < mddev->bitmap_info.max_write_behind) && + !waitqueue_active(&bitmap->behind_wait)) + alloc_behind_pages(bio, r1_bio); + + atomic_set(&r1_bio->remaining, 1); + atomic_set(&r1_bio->behind_remaining, 0); + + bitmap_startwrite(bitmap, bio->bi_sector, r1_bio->sectors, + test_bit(R1BIO_BehindIO, &r1_bio->state)); + for (i = 0; i < disks; i++) { + struct bio *mbio; + if (!r1_bio->bios[i]) + continue; + + mbio = bio_clone_mddev(bio, GFP_NOIO, mddev); + 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 | do_flush_fua | do_sync; + mbio->bi_private = r1_bio; + + if (r1_bio->behind_pages) { + struct bio_vec *bvec; + int j; + + /* Yes, I really want the '__' version so that + * we clear any unused pointer in the io_vec, rather + * than leave them unchanged. This is important + * because when we come to free the pages, we won't + * know the original bi_idx, so we just free + * them all + */ + __bio_for_each_segment(bvec, mbio, j, 0) + bvec->bv_page = r1_bio->behind_pages[j]; + if (test_bit(WriteMostly, &conf->mirrors[i].rdev->flags)) + atomic_inc(&r1_bio->behind_remaining); + } + + atomic_inc(&r1_bio->remaining); + spin_lock_irqsave(&conf->device_lock, flags); + bio_list_add(&conf->pending_bio_list, mbio); + spin_unlock_irqrestore(&conf->device_lock, flags); + } + r1_bio_write_done(r1_bio); + + /* In case raid1d snuck in to freeze_array */ + wake_up(&conf->wait_barrier); + + if (do_sync || !bitmap || !plugged) + md_wakeup_thread(mddev->thread); + + return 0; +} + +static void status(struct seq_file *seq, mddev_t *mddev) +{ + conf_t *conf = mddev->private; + int i; + + seq_printf(seq, " [%d/%d] [", conf->raid_disks, + conf->raid_disks - mddev->degraded); + rcu_read_lock(); + for (i = 0; i < conf->raid_disks; i++) { + mdk_rdev_t *rdev = rcu_dereference(conf->mirrors[i].rdev); + seq_printf(seq, "%s", + rdev && test_bit(In_sync, &rdev->flags) ? "U" : "_"); + } + rcu_read_unlock(); + seq_printf(seq, "]"); +} + + +static void error(mddev_t *mddev, mdk_rdev_t *rdev) +{ + char b[BDEVNAME_SIZE]; + conf_t *conf = mddev->private; + + /* + * 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 (test_bit(In_sync, &rdev->flags) + && (conf->raid_disks - mddev->degraded) == 1) { + /* + * Don't fail the drive, act as though we were just a + * normal single drive. + * However don't try a recovery from this drive as + * it is very likely to fail. + */ + mddev->recovery_disabled = 1; + return; + } + if (test_and_clear_bit(In_sync, &rdev->flags)) { + unsigned long flags; + spin_lock_irqsave(&conf->device_lock, flags); + mddev->degraded++; + set_bit(Faulty, &rdev->flags); + spin_unlock_irqrestore(&conf->device_lock, flags); + /* + * if recovery is running, make sure it aborts. + */ + set_bit(MD_RECOVERY_INTR, &mddev->recovery); + } else + set_bit(Faulty, &rdev->flags); + set_bit(MD_CHANGE_DEVS, &mddev->flags); + printk(KERN_ALERT + "md/raid1:%s: Disk failure on %s, disabling device.\n" + "md/raid1:%s: Operation continuing on %d devices.\n", + mdname(mddev), bdevname(rdev->bdev, b), + mdname(mddev), conf->raid_disks - mddev->degraded); +} + +static void print_conf(conf_t *conf) +{ + int i; + + printk(KERN_DEBUG "RAID1 conf printout:\n"); + if (!conf) { + printk(KERN_DEBUG "(!conf)\n"); + return; + } + printk(KERN_DEBUG " --- wd:%d rd:%d\n", conf->raid_disks - conf->mddev->degraded, + conf->raid_disks); + + rcu_read_lock(); + for (i = 0; i < conf->raid_disks; i++) { + char b[BDEVNAME_SIZE]; + mdk_rdev_t *rdev = rcu_dereference(conf->mirrors[i].rdev); + if (rdev) + printk(KERN_DEBUG " disk %d, wo:%d, o:%d, dev:%s\n", + i, !test_bit(In_sync, &rdev->flags), + !test_bit(Faulty, &rdev->flags), + bdevname(rdev->bdev,b)); + } + rcu_read_unlock(); +} + +static void close_sync(conf_t *conf) +{ + wait_barrier(conf); + allow_barrier(conf); + + mempool_destroy(conf->r1buf_pool); + conf->r1buf_pool = NULL; +} + +static int raid1_spare_active(mddev_t *mddev) +{ + int i; + conf_t *conf = mddev->private; + int count = 0; + unsigned long flags; + + /* + * Find all failed disks within the RAID1 configuration + * and mark them readable. + * Called under mddev lock, so rcu protection not needed. + */ + for (i = 0; i < conf->raid_disks; i++) { + mdk_rdev_t *rdev = conf->mirrors[i].rdev; + if (rdev + && !test_bit(Faulty, &rdev->flags) + && !test_and_set_bit(In_sync, &rdev->flags)) { + count++; + sysfs_notify_dirent(rdev->sysfs_state); + } + } + spin_lock_irqsave(&conf->device_lock, flags); + mddev->degraded -= count; + spin_unlock_irqrestore(&conf->device_lock, flags); + + print_conf(conf); + return count; +} + + +static int raid1_add_disk(mddev_t *mddev, mdk_rdev_t *rdev) +{ + conf_t *conf = mddev->private; + int err = -EEXIST; + int mirror = 0; + mirror_info_t *p; + int first = 0; + int last = mddev->raid_disks - 1; + + if (rdev->raid_disk >= 0) + first = last = rdev->raid_disk; + + for (mirror = first; mirror <= last; mirror++) + if ( !(p=conf->mirrors+mirror)->rdev) { + + disk_stack_limits(mddev->gendisk, rdev->bdev, + rdev->data_offset << 9); + /* as we don't honour merge_bvec_fn, we must + * never risk violating it, so limit + * ->max_segments to one lying with a single + * page, as a one page request is never in + * violation. + */ + if (rdev->bdev->bd_disk->queue->merge_bvec_fn) { + blk_queue_max_segments(mddev->queue, 1); + blk_queue_segment_boundary(mddev->queue, + PAGE_CACHE_SIZE - 1); + } + + p->head_position = 0; + rdev->raid_disk = mirror; + err = 0; + /* As all devices are equivalent, we don't need a full recovery + * if this was recently any drive of the array + */ + if (rdev->saved_raid_disk < 0) + conf->fullsync = 1; + rcu_assign_pointer(p->rdev, rdev); + break; + } + md_integrity_add_rdev(rdev, mddev); + print_conf(conf); + return err; +} + +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 (test_bit(In_sync, &rdev->flags) || + atomic_read(&rdev->nr_pending)) { + err = -EBUSY; + goto abort; + } + /* Only remove non-faulty devices if recovery + * is not possible. + */ + if (!test_bit(Faulty, &rdev->flags) && + !mddev->recovery_disabled && + mddev->degraded < conf->raid_disks) { + err = -EBUSY; + goto abort; + } + p->rdev = NULL; + synchronize_rcu(); + if (atomic_read(&rdev->nr_pending)) { + /* lost the race, try later */ + err = -EBUSY; + p->rdev = rdev; + goto abort; + } + err = md_integrity_register(mddev); + } +abort: + + print_conf(conf); + return err; +} + + +static void end_sync_read(struct bio *bio, int error) +{ + r1bio_t *r1_bio = bio->bi_private; + int i; + + for (i=r1_bio->mddev->raid_disks; i--; ) + if (r1_bio->bios[i] == bio) + break; + BUG_ON(i < 0); + update_head_pos(i, 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 (test_bit(BIO_UPTODATE, &bio->bi_flags)) + set_bit(R1BIO_Uptodate, &r1_bio->state); + + if (atomic_dec_and_test(&r1_bio->remaining)) + reschedule_retry(r1_bio); +} + +static void end_sync_write(struct bio *bio, int error) +{ + int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags); + r1bio_t *r1_bio = bio->bi_private; + mddev_t *mddev = r1_bio->mddev; + conf_t *conf = mddev->private; + int i; + int mirror=0; + + for (i = 0; i < conf->raid_disks; i++) + if (r1_bio->bios[i] == bio) { + mirror = i; + break; + } + if (!uptodate) { + sector_t sync_blocks = 0; + sector_t s = r1_bio->sector; + long sectors_to_go = r1_bio->sectors; + /* make sure these bits doesn't get cleared. */ + do { + bitmap_end_sync(mddev->bitmap, s, + &sync_blocks, 1); + s += sync_blocks; + sectors_to_go -= sync_blocks; + } while (sectors_to_go > 0); + md_error(mddev, conf->mirrors[mirror].rdev); + } + + update_head_pos(mirror, r1_bio); + + if (atomic_dec_and_test(&r1_bio->remaining)) { + sector_t s = r1_bio->sectors; + put_buf(r1_bio); + md_done_sync(mddev, s, uptodate); + } +} + +static int fix_sync_read_error(r1bio_t *r1_bio) +{ + /* Try some synchronous reads of other devices to get + * good data, much like with normal read errors. Only + * read into the pages we already have so we don't + * need to re-issue the read request. + * We don't need to freeze the array, because being in an + * active sync request, there is no normal IO, and + * no overlapping syncs. + */ + mddev_t *mddev = r1_bio->mddev; + conf_t *conf = mddev->private; + struct bio *bio = r1_bio->bios[r1_bio->read_disk]; + sector_t sect = r1_bio->sector; + int sectors = r1_bio->sectors; + int idx = 0; + + while(sectors) { + int s = sectors; + int d = r1_bio->read_disk; + int success = 0; + mdk_rdev_t *rdev; + int start; + + if (s > (PAGE_SIZE>>9)) + s = PAGE_SIZE >> 9; + do { + if (r1_bio->bios[d]->bi_end_io == end_sync_read) { + /* No rcu protection needed here devices + * can only be removed when no resync is + * active, and resync is currently active + */ + rdev = conf->mirrors[d].rdev; + if (sync_page_io(rdev, + sect, + s<<9, + bio->bi_io_vec[idx].bv_page, + READ, false)) { + success = 1; + break; + } + } + d++; + if (d == conf->raid_disks) + d = 0; + } while (!success && d != r1_bio->read_disk); + + if (!success) { + char b[BDEVNAME_SIZE]; + /* Cannot read from anywhere, array is toast */ + md_error(mddev, conf->mirrors[r1_bio->read_disk].rdev); + printk(KERN_ALERT "md/raid1:%s: %s: unrecoverable I/O read error" + " for block %llu\n", + mdname(mddev), + bdevname(bio->bi_bdev, b), + (unsigned long long)r1_bio->sector); + md_done_sync(mddev, r1_bio->sectors, 0); + put_buf(r1_bio); + return 0; + } + + start = d; + /* write it back and re-read */ + while (d != r1_bio->read_disk) { + if (d == 0) + d = conf->raid_disks; + d--; + if (r1_bio->bios[d]->bi_end_io != end_sync_read) + continue; + rdev = conf->mirrors[d].rdev; + if (sync_page_io(rdev, + sect, + s<<9, + bio->bi_io_vec[idx].bv_page, + WRITE, false) == 0) { + r1_bio->bios[d]->bi_end_io = NULL; + rdev_dec_pending(rdev, mddev); + md_error(mddev, rdev); + } else + atomic_add(s, &rdev->corrected_errors); + } + d = start; + while (d != r1_bio->read_disk) { + if (d == 0) + d = conf->raid_disks; + d--; + if (r1_bio->bios[d]->bi_end_io != end_sync_read) + continue; + rdev = conf->mirrors[d].rdev; + if (sync_page_io(rdev, + sect, + s<<9, + bio->bi_io_vec[idx].bv_page, + READ, false) == 0) + md_error(mddev, rdev); + } + sectors -= s; + sect += s; + idx ++; + } + set_bit(R1BIO_Uptodate, &r1_bio->state); + set_bit(BIO_UPTODATE, &bio->bi_flags); + return 1; +} + +static int process_checks(r1bio_t *r1_bio) +{ + /* We have read all readable devices. If we haven't + * got the block, then there is no hope left. + * If we have, then we want to do a comparison + * and skip the write if everything is the same. + * If any blocks failed to read, then we need to + * attempt an over-write + */ + mddev_t *mddev = r1_bio->mddev; + conf_t *conf = mddev->private; + int primary; + int i; + + for (primary = 0; primary < conf->raid_disks; primary++) + if (r1_bio->bios[primary]->bi_end_io == end_sync_read && + test_bit(BIO_UPTODATE, &r1_bio->bios[primary]->bi_flags)) { + r1_bio->bios[primary]->bi_end_io = NULL; + rdev_dec_pending(conf->mirrors[primary].rdev, mddev); + break; + } + r1_bio->read_disk = primary; + for (i = 0; i < conf->raid_disks; i++) { + int j; + int vcnt = r1_bio->sectors >> (PAGE_SHIFT- 9); + struct bio *pbio = r1_bio->bios[primary]; + struct bio *sbio = r1_bio->bios[i]; + int size; + + if (r1_bio->bios[i]->bi_end_io != end_sync_read) + continue; + + if (test_bit(BIO_UPTODATE, &sbio->bi_flags)) { + for (j = vcnt; j-- ; ) { + struct page *p, *s; + p = pbio->bi_io_vec[j].bv_page; + s = sbio->bi_io_vec[j].bv_page; + if (memcmp(page_address(p), + page_address(s), + PAGE_SIZE)) + break; + } + } else + j = 0; + if (j >= 0) + mddev->resync_mismatches += r1_bio->sectors; + if (j < 0 || (test_bit(MD_RECOVERY_CHECK, &mddev->recovery) + && test_bit(BIO_UPTODATE, &sbio->bi_flags))) { + /* No need to write to this device. */ + sbio->bi_end_io = NULL; + rdev_dec_pending(conf->mirrors[i].rdev, mddev); + continue; + } + /* fixup the bio for reuse */ + sbio->bi_vcnt = vcnt; + sbio->bi_size = r1_bio->sectors << 9; + sbio->bi_idx = 0; + sbio->bi_phys_segments = 0; + sbio->bi_flags &= ~(BIO_POOL_MASK - 1); + sbio->bi_flags |= 1 << BIO_UPTODATE; + sbio->bi_next = NULL; + sbio->bi_sector = r1_bio->sector + + conf->mirrors[i].rdev->data_offset; + sbio->bi_bdev = conf->mirrors[i].rdev->bdev; + size = sbio->bi_size; + for (j = 0; j < vcnt ; j++) { + struct bio_vec *bi; + bi = &sbio->bi_io_vec[j]; + bi->bv_offset = 0; + if (size > PAGE_SIZE) + bi->bv_len = PAGE_SIZE; + else + bi->bv_len = size; + size -= PAGE_SIZE; + memcpy(page_address(bi->bv_page), + page_address(pbio->bi_io_vec[j].bv_page), + PAGE_SIZE); + } + } + return 0; +} + +static void sync_request_write(mddev_t *mddev, r1bio_t *r1_bio) +{ + conf_t *conf = mddev->private; + int i; + int disks = conf->raid_disks; + struct bio *bio, *wbio; + + bio = r1_bio->bios[r1_bio->read_disk]; + + if (!test_bit(R1BIO_Uptodate, &r1_bio->state)) + /* ouch - failed to read all of that. */ + if (!fix_sync_read_error(r1_bio)) + return; + + if (test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery)) + if (process_checks(r1_bio) < 0) + return; + /* + * schedule writes + */ + atomic_set(&r1_bio->remaining, 1); + for (i = 0; i < disks ; i++) { + wbio = r1_bio->bios[i]; + if (wbio->bi_end_io == NULL || + (wbio->bi_end_io == end_sync_read && + (i == r1_bio->read_disk || + !test_bit(MD_RECOVERY_SYNC, &mddev->recovery)))) + continue; + + wbio->bi_rw = WRITE; + wbio->bi_end_io = end_sync_write; + 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)) { + /* if we're here, all write(s) have completed, so clean up */ + 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 fix_read_error(conf_t *conf, int read_disk, + sector_t sect, int sectors) +{ + mddev_t *mddev = conf->mddev; + while(sectors) { + int s = sectors; + int d = read_disk; + int success = 0; + int start; + mdk_rdev_t *rdev; + + if (s > (PAGE_SIZE>>9)) + s = PAGE_SIZE >> 9; + + do { + /* Note: no rcu protection needed here + * as this is synchronous in the raid1d thread + * which is the thread that might remove + * a device. If raid1d ever becomes multi-threaded.... + */ + rdev = conf->mirrors[d].rdev; + if (rdev && + test_bit(In_sync, &rdev->flags) && + sync_page_io(rdev, sect, s<<9, + conf->tmppage, READ, false)) + success = 1; + else { + d++; + if (d == conf->raid_disks) + d = 0; + } + } while (!success && d != read_disk); + + if (!success) { + /* Cannot read from anywhere -- bye bye array */ + md_error(mddev, conf->mirrors[read_disk].rdev); + break; + } + /* write it back and re-read */ + start = d; + while (d != read_disk) { + if (d==0) + d = conf->raid_disks; + d--; + rdev = conf->mirrors[d].rdev; + if (rdev && + test_bit(In_sync, &rdev->flags)) { + if (sync_page_io(rdev, sect, s<<9, + conf->tmppage, WRITE, false) + == 0) + /* Well, this device is dead */ + md_error(mddev, rdev); + } + } + d = start; + while (d != read_disk) { + char b[BDEVNAME_SIZE]; + if (d==0) + d = conf->raid_disks; + d--; + rdev = conf->mirrors[d].rdev; + if (rdev && + test_bit(In_sync, &rdev->flags)) { + if (sync_page_io(rdev, sect, s<<9, + conf->tmppage, READ, false) + == 0) + /* Well, this device is dead */ + md_error(mddev, rdev); + else { + atomic_add(s, &rdev->corrected_errors); + printk(KERN_INFO + "md/raid1:%s: read error corrected " + "(%d sectors at %llu on %s)\n", + mdname(mddev), s, + (unsigned long long)(sect + + rdev->data_offset), + bdevname(rdev->bdev, b)); + } + } + } + sectors -= s; + sect += s; + } +} + +static void raid1d(mddev_t *mddev) +{ + r1bio_t *r1_bio; + struct bio *bio; + unsigned long flags; + conf_t *conf = mddev->private; + struct list_head *head = &conf->retry_list; + mdk_rdev_t *rdev; + struct blk_plug plug; + + md_check_recovery(mddev); + + blk_start_plug(&plug); + for (;;) { + char b[BDEVNAME_SIZE]; + + if (atomic_read(&mddev->plug_cnt) == 0) + flush_pending_writes(conf); + + spin_lock_irqsave(&conf->device_lock, flags); + if (list_empty(head)) { + spin_unlock_irqrestore(&conf->device_lock, flags); + break; + } + r1_bio = list_entry(head->prev, r1bio_t, retry_list); + list_del(head->prev); + conf->nr_queued--; + spin_unlock_irqrestore(&conf->device_lock, flags); + + mddev = r1_bio->mddev; + conf = mddev->private; + if (test_bit(R1BIO_IsSync, &r1_bio->state)) + sync_request_write(mddev, r1_bio); + else { + int disk; + + /* we got a read error. Maybe the drive is bad. Maybe just + * the block and we can fix it. + * We freeze all other IO, and try reading the block from + * other devices. When we find one, we re-write + * and check it that fixes the read error. + * This is all done synchronously while the array is + * frozen + */ + if (mddev->ro == 0) { + freeze_array(conf); + fix_read_error(conf, r1_bio->read_disk, + r1_bio->sector, + r1_bio->sectors); + unfreeze_array(conf); + } else + md_error(mddev, + conf->mirrors[r1_bio->read_disk].rdev); + + bio = r1_bio->bios[r1_bio->read_disk]; + if ((disk=read_balance(conf, r1_bio)) == -1) { + printk(KERN_ALERT "md/raid1:%s: %s: unrecoverable I/O" + " read error for block %llu\n", + mdname(mddev), + bdevname(bio->bi_bdev,b), + (unsigned long long)r1_bio->sector); + raid_end_bio_io(r1_bio); + } else { + const unsigned long do_sync = r1_bio->master_bio->bi_rw & REQ_SYNC; + r1_bio->bios[r1_bio->read_disk] = + mddev->ro ? IO_BLOCKED : NULL; + r1_bio->read_disk = disk; + bio_put(bio); + bio = bio_clone_mddev(r1_bio->master_bio, + GFP_NOIO, mddev); + r1_bio->bios[r1_bio->read_disk] = bio; + rdev = conf->mirrors[disk].rdev; + if (printk_ratelimit()) + printk(KERN_ERR "md/raid1:%s: redirecting sector %llu to" + " other mirror: %s\n", + mdname(mddev), + (unsigned long long)r1_bio->sector, + bdevname(rdev->bdev,b)); + 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 | do_sync; + bio->bi_private = r1_bio; + generic_make_request(bio); + } + } + cond_resched(); + } + blk_finish_plug(&plug); +} + + +static int init_resync(conf_t *conf) +{ + int buffs; + + buffs = RESYNC_WINDOW / RESYNC_BLOCK_SIZE; + BUG_ON(conf->r1buf_pool); + 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 sector_t sync_request(mddev_t *mddev, sector_t sector_nr, int *skipped, int go_faster) +{ + conf_t *conf = mddev->private; + r1bio_t *r1_bio; + struct bio *bio; + sector_t max_sector, nr_sectors; + int disk = -1; + int i; + int wonly = -1; + int write_targets = 0, read_targets = 0; + sector_t sync_blocks; + int still_degraded = 0; + + if (!conf->r1buf_pool) + if (init_resync(conf)) + return 0; + + max_sector = mddev->dev_sectors; + if (sector_nr >= max_sector) { + /* If we aborted, we need to abort the + * sync on the 'current' bitmap chunk (there will + * only be one in raid1 resync. + * We can find the current addess in mddev->curr_resync + */ + if (mddev->curr_resync < max_sector) /* aborted */ + bitmap_end_sync(mddev->bitmap, mddev->curr_resync, + &sync_blocks, 1); + else /* completed sync */ + conf->fullsync = 0; + + bitmap_close_sync(mddev->bitmap); + close_sync(conf); + return 0; + } + + if (mddev->bitmap == NULL && + mddev->recovery_cp == MaxSector && + !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery) && + conf->fullsync == 0) { + *skipped = 1; + return max_sector - sector_nr; + } + /* before building a request, check if we can skip these blocks.. + * This call the bitmap_start_sync doesn't actually record anything + */ + if (!bitmap_start_sync(mddev->bitmap, sector_nr, &sync_blocks, 1) && + !conf->fullsync && !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery)) { + /* We can skip this block, and probably several more */ + *skipped = 1; + return sync_blocks; + } + /* + * If there is non-resync activity waiting for a turn, + * and resync is going fast enough, + * then let it though before starting on this new sync request. + */ + if (!go_faster && conf->nr_waiting) + msleep_interruptible(1000); + + bitmap_cond_end_sync(mddev->bitmap, sector_nr); + r1_bio = mempool_alloc(conf->r1buf_pool, GFP_NOIO); + raise_barrier(conf); + + conf->next_resync = sector_nr; + + rcu_read_lock(); + /* + * If we get a correctably read error during resync or recovery, + * we might want to read from a different device. So we + * flag all drives that could conceivably be read from for READ, + * and any others (which will be non-In_sync devices) for WRITE. + * If a read fails, we try reading from something else for which READ + * is OK. + */ + + r1_bio->mddev = mddev; + r1_bio->sector = sector_nr; + r1_bio->state = 0; + set_bit(R1BIO_IsSync, &r1_bio->state); + + for (i=0; i < conf->raid_disks; i++) { + mdk_rdev_t *rdev; + bio = r1_bio->bios[i]; + + /* take from bio_init */ + bio->bi_next = NULL; + bio->bi_flags &= ~(BIO_POOL_MASK-1); + bio->bi_flags |= 1 << BIO_UPTODATE; + bio->bi_comp_cpu = -1; + bio->bi_rw = READ; + bio->bi_vcnt = 0; + bio->bi_idx = 0; + bio->bi_phys_segments = 0; + bio->bi_size = 0; + bio->bi_end_io = NULL; + bio->bi_private = NULL; + + rdev = rcu_dereference(conf->mirrors[i].rdev); + if (rdev == NULL || + test_bit(Faulty, &rdev->flags)) { + still_degraded = 1; + continue; + } else if (!test_bit(In_sync, &rdev->flags)) { + bio->bi_rw = WRITE; + bio->bi_end_io = end_sync_write; + write_targets ++; + } else { + /* may need to read from here */ + bio->bi_rw = READ; + bio->bi_end_io = end_sync_read; + if (test_bit(WriteMostly, &rdev->flags)) { + if (wonly < 0) + wonly = i; + } else { + if (disk < 0) + disk = i; + } + read_targets++; + } + atomic_inc(&rdev->nr_pending); + bio->bi_sector = sector_nr + rdev->data_offset; + bio->bi_bdev = rdev->bdev; + bio->bi_private = r1_bio; + } + rcu_read_unlock(); + if (disk < 0) + disk = wonly; + r1_bio->read_disk = disk; + + if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery) && read_targets > 0) + /* extra read targets are also write targets */ + write_targets += read_targets-1; + + if (write_targets == 0 || read_targets == 0) { + /* There is nowhere to write, so all non-sync + * drives must be failed - so we are finished + */ + sector_t rv = max_sector - sector_nr; + *skipped = 1; + put_buf(r1_bio); + return rv; + } + + if (max_sector > mddev->resync_max) + max_sector = mddev->resync_max; /* Don't do IO beyond here */ + nr_sectors = 0; + sync_blocks = 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; + if (sync_blocks == 0) { + if (!bitmap_start_sync(mddev->bitmap, sector_nr, + &sync_blocks, still_degraded) && + !conf->fullsync && + !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery)) + break; + BUG_ON(sync_blocks < (PAGE_SIZE>>9)); + if ((len >> 9) > sync_blocks) + len = sync_blocks<<9; + } + + for (i=0 ; i < conf->raid_disks; i++) { + bio = r1_bio->bios[i]; + if (bio->bi_end_io) { + page = bio->bi_io_vec[bio->bi_vcnt].bv_page; + if (bio_add_page(bio, page, len, 0) == 0) { + /* stop here */ + bio->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; + sync_blocks -= (len>>9); + } while (r1_bio->bios[disk]->bi_vcnt < RESYNC_PAGES); + bio_full: + r1_bio->sectors = nr_sectors; + + /* For a user-requested sync, we read all readable devices and do a + * compare + */ + if (test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery)) { + atomic_set(&r1_bio->remaining, read_targets); + for (i=0; i<conf->raid_disks; i++) { + bio = r1_bio->bios[i]; + if (bio->bi_end_io == end_sync_read) { + md_sync_acct(bio->bi_bdev, nr_sectors); + generic_make_request(bio); + } + } + } else { + atomic_set(&r1_bio->remaining, 1); + bio = r1_bio->bios[r1_bio->read_disk]; + md_sync_acct(bio->bi_bdev, nr_sectors); + generic_make_request(bio); + + } + return nr_sectors; +} + +static sector_t raid1_size(mddev_t *mddev, sector_t sectors, int raid_disks) +{ + if (sectors) + return sectors; + + return mddev->dev_sectors; +} + +static conf_t *setup_conf(mddev_t *mddev) +{ + conf_t *conf; + int i; + mirror_info_t *disk; + mdk_rdev_t *rdev; + int err = -ENOMEM; + + conf = kzalloc(sizeof(conf_t), GFP_KERNEL); + if (!conf) + goto abort; + + conf->mirrors = kzalloc(sizeof(struct mirror_info)*mddev->raid_disks, + GFP_KERNEL); + if (!conf->mirrors) + goto abort; + + conf->tmppage = alloc_page(GFP_KERNEL); + if (!conf->tmppage) + goto abort; + + conf->poolinfo = kzalloc(sizeof(*conf->poolinfo), GFP_KERNEL); + if (!conf->poolinfo) + goto abort; + 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 abort; + + conf->poolinfo->mddev = mddev; + + spin_lock_init(&conf->device_lock); + list_for_each_entry(rdev, &mddev->disks, same_set) { + int disk_idx = rdev->raid_disk; + if (disk_idx >= mddev->raid_disks + || disk_idx < 0) + continue; + disk = conf->mirrors + disk_idx; + + disk->rdev = rdev; + + disk->head_position = 0; + } + conf->raid_disks = mddev->raid_disks; + conf->mddev = mddev; + INIT_LIST_HEAD(&conf->retry_list); + + spin_lock_init(&conf->resync_lock); + init_waitqueue_head(&conf->wait_barrier); + + bio_list_init(&conf->pending_bio_list); + + conf->last_used = -1; + for (i = 0; i < conf->raid_disks; i++) { + + disk = conf->mirrors + i; + + if (!disk->rdev || + !test_bit(In_sync, &disk->rdev->flags)) { + disk->head_position = 0; + if (disk->rdev) + conf->fullsync = 1; + } else if (conf->last_used < 0) + /* + * The first working device is used as a + * starting point to read balancing. + */ + conf->last_used = i; + } + + err = -EIO; + if (conf->last_used < 0) { + printk(KERN_ERR "md/raid1:%s: no operational mirrors\n", + mdname(mddev)); + goto abort; + } + err = -ENOMEM; + conf->thread = md_register_thread(raid1d, mddev, NULL); + if (!conf->thread) { + printk(KERN_ERR + "md/raid1:%s: couldn't allocate thread\n", + mdname(mddev)); + goto abort; + } + + return conf; + + abort: + if (conf) { + if (conf->r1bio_pool) + mempool_destroy(conf->r1bio_pool); + kfree(conf->mirrors); + safe_put_page(conf->tmppage); + kfree(conf->poolinfo); + kfree(conf); + } + return ERR_PTR(err); +} + +static int run(mddev_t *mddev) +{ + conf_t *conf; + int i; + mdk_rdev_t *rdev; + + if (mddev->level != 1) { + printk(KERN_ERR "md/raid1:%s: raid level not set to mirroring (%d)\n", + mdname(mddev), mddev->level); + return -EIO; + } + if (mddev->reshape_position != MaxSector) { + printk(KERN_ERR "md/raid1:%s: reshape_position set but not supported\n", + mdname(mddev)); + return -EIO; + } + /* + * copy the already verified devices into our private RAID1 + * bookkeeping area. [whatever we allocate in run(), + * should be freed in stop()] + */ + if (mddev->private == NULL) + conf = setup_conf(mddev); + else + conf = mddev->private; + + if (IS_ERR(conf)) + return PTR_ERR(conf); + + list_for_each_entry(rdev, &mddev->disks, same_set) { + if (!mddev->gendisk) + continue; + disk_stack_limits(mddev->gendisk, rdev->bdev, + rdev->data_offset << 9); + /* as we don't honour merge_bvec_fn, we must never risk + * violating it, so limit ->max_segments to 1 lying within + * a single page, as a one page request is never in violation. + */ + if (rdev->bdev->bd_disk->queue->merge_bvec_fn) { + blk_queue_max_segments(mddev->queue, 1); + blk_queue_segment_boundary(mddev->queue, + PAGE_CACHE_SIZE - 1); + } + } + + mddev->degraded = 0; + for (i=0; i < conf->raid_disks; i++) + if (conf->mirrors[i].rdev == NULL || + !test_bit(In_sync, &conf->mirrors[i].rdev->flags) || + test_bit(Faulty, &conf->mirrors[i].rdev->flags)) + mddev->degraded++; + + if (conf->raid_disks - mddev->degraded == 1) + mddev->recovery_cp = MaxSector; + + if (mddev->recovery_cp != MaxSector) + printk(KERN_NOTICE "md/raid1:%s: not clean" + " -- starting background reconstruction\n", + mdname(mddev)); + printk(KERN_INFO + "md/raid1:%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->thread = conf->thread; + conf->thread = NULL; + mddev->private = conf; + + md_set_array_sectors(mddev, raid1_size(mddev, 0, 0)); + + if (mddev->queue) { + mddev->queue->backing_dev_info.congested_fn = raid1_congested; + mddev->queue->backing_dev_info.congested_data = mddev; + } + return md_integrity_register(mddev); +} + +static int stop(mddev_t *mddev) +{ + conf_t *conf = mddev->private; + struct bitmap *bitmap = mddev->bitmap; + + /* wait for behind writes to complete */ + if (bitmap && atomic_read(&bitmap->behind_writes) > 0) { + printk(KERN_INFO "md/raid1:%s: behind writes in progress - waiting to stop.\n", + mdname(mddev)); + /* need to kick something here to make sure I/O goes? */ + wait_event(bitmap->behind_wait, + atomic_read(&bitmap->behind_writes) == 0); + } + + raise_barrier(conf); + lower_barrier(conf); + + md_unregister_thread(&mddev->thread); + if (conf->r1bio_pool) + mempool_destroy(conf->r1bio_pool); + kfree(conf->mirrors); + 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. + */ + md_set_array_sectors(mddev, raid1_size(mddev, sectors, 0)); + if (mddev->array_sectors > raid1_size(mddev, sectors, 0)) + return -EINVAL; + set_capacity(mddev->gendisk, mddev->array_sectors); + revalidate_disk(mddev->gendisk); + if (sectors > mddev->dev_sectors && + mddev->recovery_cp > mddev->dev_sectors) { + mddev->recovery_cp = mddev->dev_sectors; + set_bit(MD_RECOVERY_NEEDED, &mddev->recovery); + } + mddev->dev_sectors = sectors; + mddev->resync_max_sectors = sectors; + return 0; +} + +static int raid1_reshape(mddev_t *mddev) +{ + /* 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. + * + * At the same time, we "pack" the devices so that all the missing + * devices have the higher raid_disk numbers. + */ + mempool_t *newpool, *oldpool; + struct pool_info *newpoolinfo; + mirror_info_t *newmirrors; + conf_t *conf = mddev->private; + int cnt, raid_disks; + unsigned long flags; + int d, d2, err; + + /* Cannot change chunk_size, layout, or level */ + if (mddev->chunk_sectors != mddev->new_chunk_sectors || + mddev->layout != mddev->new_layout || + mddev->level != mddev->new_level) { + mddev->new_chunk_sectors = mddev->chunk_sectors; + mddev->new_layout = mddev->layout; + mddev->new_level = mddev->level; + return -EINVAL; + } + + err = md_allow_write(mddev); + if (err) + return err; + + raid_disks = mddev->raid_disks + mddev->delta_disks; + + if (raid_disks < conf->raid_disks) { + cnt=0; + for (d= 0; d < conf->raid_disks; d++) + if (conf->mirrors[d].rdev) + cnt++; + if (cnt > raid_disks) + 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 = kzalloc(sizeof(struct mirror_info) * raid_disks, GFP_KERNEL); + if (!newmirrors) { + kfree(newpoolinfo); + mempool_destroy(newpool); + return -ENOMEM; + } + + raise_barrier(conf); + + /* ok, everything is stopped */ + oldpool = conf->r1bio_pool; + conf->r1bio_pool = newpool; + + for (d = d2 = 0; d < conf->raid_disks; d++) { + mdk_rdev_t *rdev = conf->mirrors[d].rdev; + if (rdev && rdev->raid_disk != d2) { + char nm[20]; + sprintf(nm, "rd%d", rdev->raid_disk); + sysfs_remove_link(&mddev->kobj, nm); + rdev->raid_disk = d2; + sprintf(nm, "rd%d", rdev->raid_disk); + sysfs_remove_link(&mddev->kobj, nm); + if (sysfs_create_link(&mddev->kobj, + &rdev->kobj, nm)) + printk(KERN_WARNING + "md/raid1:%s: cannot register " + "%s\n", + mdname(mddev), nm); + } + if (rdev) + newmirrors[d2++].rdev = rdev; + } + kfree(conf->mirrors); + conf->mirrors = newmirrors; + kfree(conf->poolinfo); + conf->poolinfo = newpoolinfo; + + spin_lock_irqsave(&conf->device_lock, flags); + mddev->degraded += (raid_disks - conf->raid_disks); + spin_unlock_irqrestore(&conf->device_lock, flags); + conf->raid_disks = mddev->raid_disks = raid_disks; + mddev->delta_disks = 0; + + conf->last_used = 0; /* just make sure it is in-range */ + lower_barrier(conf); + + set_bit(MD_RECOVERY_NEEDED, &mddev->recovery); + md_wakeup_thread(mddev->thread); + + mempool_destroy(oldpool); + return 0; +} + +static void raid1_quiesce(mddev_t *mddev, int state) +{ + conf_t *conf = mddev->private; + + switch(state) { + case 2: /* wake for suspend */ + wake_up(&conf->wait_barrier); + break; + case 1: + raise_barrier(conf); + break; + case 0: + lower_barrier(conf); + break; + } +} + +static void *raid1_takeover(mddev_t *mddev) +{ + /* raid1 can take over: + * raid5 with 2 devices, any layout or chunk size + */ + if (mddev->level == 5 && mddev->raid_disks == 2) { + conf_t *conf; + mddev->new_level = 1; + mddev->new_layout = 0; + mddev->new_chunk_sectors = 0; + conf = setup_conf(mddev); + if (!IS_ERR(conf)) + conf->barrier = 1; + return conf; + } + return ERR_PTR(-EINVAL); +} + +static struct mdk_personality raid1_personality = +{ + .name = "raid1", + .level = 1, + .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, + .size = raid1_size, + .check_reshape = raid1_reshape, + .quiesce = raid1_quiesce, + .takeover = raid1_takeover, +}; + +static int __init raid_init(void) +{ + return register_md_personality(&raid1_personality); +} + +static void raid_exit(void) +{ + unregister_md_personality(&raid1_personality); +} + +module_init(raid_init); +module_exit(raid_exit); +MODULE_LICENSE("GPL"); +MODULE_DESCRIPTION("RAID1 (mirroring) personality for MD"); +MODULE_ALIAS("md-personality-3"); /* RAID1 */ +MODULE_ALIAS("md-raid1"); +MODULE_ALIAS("md-level-1"); |