/* * raid10.c : Multiple Devices driver for Linux * * Copyright (C) 2000-2004 Neil Brown * * RAID-10 support for md. * * Base on code in raid1.c. See raid1.c for futher copyright information. * * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2, or (at your option) * any later version. * * You should have received a copy of the GNU General Public License * (for example /usr/src/linux/COPYING); if not, write to the Free * Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */ #include "dm-bio-list.h" #include <linux/raid/raid10.h> #include <linux/raid/bitmap.h> /* * RAID10 provides a combination of RAID0 and RAID1 functionality. * The layout of data is defined by * chunk_size * raid_disks * near_copies (stored in low byte of layout) * far_copies (stored in second byte of layout) * far_offset (stored in bit 16 of layout ) * * The data to be stored is divided into chunks using chunksize. * Each device is divided into far_copies sections. * In each section, chunks are laid out in a style similar to raid0, but * near_copies copies of each chunk is stored (each on a different drive). * The starting device for each section is offset near_copies from the starting * device of the previous section. * Thus they are (near_copies*far_copies) of each chunk, and each is on a different * drive. * near_copies and far_copies must be at least one, and their product is at most * raid_disks. * * If far_offset is true, then the far_copies are handled a bit differently. * The copies are still in different stripes, but instead of be very far apart * on disk, there are adjacent stripes. */ /* * Number of guaranteed r10bios in case of extreme VM load: */ #define NR_RAID10_BIOS 256 static void unplug_slaves(mddev_t *mddev); static void allow_barrier(conf_t *conf); static void lower_barrier(conf_t *conf); static void * r10bio_pool_alloc(gfp_t gfp_flags, void *data) { conf_t *conf = data; r10bio_t *r10_bio; int size = offsetof(struct r10bio_s, devs[conf->copies]); /* allocate a r10bio with room for raid_disks entries in the bios array */ r10_bio = kzalloc(size, gfp_flags); if (!r10_bio) unplug_slaves(conf->mddev); return r10_bio; } static void r10bio_pool_free(void *r10_bio, void *data) { kfree(r10_bio); } /* Maximum size of each resync request */ #define RESYNC_BLOCK_SIZE (64*1024) #define RESYNC_PAGES ((RESYNC_BLOCK_SIZE + PAGE_SIZE-1) / PAGE_SIZE) /* amount of memory to reserve for resync requests */ #define RESYNC_WINDOW (1024*1024) /* maximum number of concurrent requests, memory permitting */ #define RESYNC_DEPTH (32*1024*1024/RESYNC_BLOCK_SIZE) /* * When performing a resync, we need to read and compare, so * we need as many pages are there are copies. * When performing a recovery, we need 2 bios, one for read, * one for write (we recover only one drive per r10buf) * */ static void * r10buf_pool_alloc(gfp_t gfp_flags, void *data) { conf_t *conf = data; struct page *page; r10bio_t *r10_bio; struct bio *bio; int i, j; int nalloc; r10_bio = r10bio_pool_alloc(gfp_flags, conf); if (!r10_bio) { unplug_slaves(conf->mddev); return NULL; } if (test_bit(MD_RECOVERY_SYNC, &conf->mddev->recovery)) nalloc = conf->copies; /* resync */ else nalloc = 2; /* recovery */ /* * Allocate bios. */ for (j = nalloc ; j-- ; ) { bio = bio_alloc(gfp_flags, RESYNC_PAGES); if (!bio) goto out_free_bio; r10_bio->devs[j].bio = bio; } /* * Allocate RESYNC_PAGES data pages and attach them * where needed. */ for (j = 0 ; j < nalloc; j++) { bio = r10_bio->devs[j].bio; for (i = 0; i < RESYNC_PAGES; i++) { page = alloc_page(gfp_flags); if (unlikely(!page)) goto out_free_pages; bio->bi_io_vec[i].bv_page = page; } } return r10_bio; out_free_pages: for ( ; i > 0 ; i--) safe_put_page(bio->bi_io_vec[i-1].bv_page); while (j--) for (i = 0; i < RESYNC_PAGES ; i++) safe_put_page(r10_bio->devs[j].bio->bi_io_vec[i].bv_page); j = -1; out_free_bio: while ( ++j < nalloc ) bio_put(r10_bio->devs[j].bio); r10bio_pool_free(r10_bio, conf); return NULL; } static void r10buf_pool_free(void *__r10_bio, void *data) { int i; conf_t *conf = data; r10bio_t *r10bio = __r10_bio; int j; for (j=0; j < conf->copies; j++) { struct bio *bio = r10bio->devs[j].bio; if (bio) { for (i = 0; i < RESYNC_PAGES; i++) { safe_put_page(bio->bi_io_vec[i].bv_page); bio->bi_io_vec[i].bv_page = NULL; } bio_put(bio); } } r10bio_pool_free(r10bio, conf); } static void put_all_bios(conf_t *conf, r10bio_t *r10_bio) { int i; for (i = 0; i < conf->copies; i++) { struct bio **bio = & r10_bio->devs[i].bio; if (*bio && *bio != IO_BLOCKED) bio_put(*bio); *bio = NULL; } } static void free_r10bio(r10bio_t *r10_bio) { conf_t *conf = mddev_to_conf(r10_bio->mddev); /* * Wake up any possible resync thread that waits for the device * to go idle. */ allow_barrier(conf); put_all_bios(conf, r10_bio); mempool_free(r10_bio, conf->r10bio_pool); } static void put_buf(r10bio_t *r10_bio) { conf_t *conf = mddev_to_conf(r10_bio->mddev); mempool_free(r10_bio, conf->r10buf_pool); lower_barrier(conf); } static void reschedule_retry(r10bio_t *r10_bio) { unsigned long flags; mddev_t *mddev = r10_bio->mddev; conf_t *conf = mddev_to_conf(mddev); spin_lock_irqsave(&conf->device_lock, flags); list_add(&r10_bio->retry_list, &conf->retry_list); conf->nr_queued ++; spin_unlock_irqrestore(&conf->device_lock, flags); /* wake up frozen array... */ 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(r10bio_t *r10_bio) { struct bio *bio = r10_bio->master_bio; bio_endio(bio, test_bit(R10BIO_Uptodate, &r10_bio->state) ? 0 : -EIO); free_r10bio(r10_bio); } /* * Update disk head position estimator based on IRQ completion info. */ static inline void update_head_pos(int slot, r10bio_t *r10_bio) { conf_t *conf = mddev_to_conf(r10_bio->mddev); conf->mirrors[r10_bio->devs[slot].devnum].head_position = r10_bio->devs[slot].addr + (r10_bio->sectors); } static void raid10_end_read_request(struct bio *bio, int error) { int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags); r10bio_t * r10_bio = (r10bio_t *)(bio->bi_private); int slot, dev; conf_t *conf = mddev_to_conf(r10_bio->mddev); slot = r10_bio->read_slot; dev = r10_bio->devs[slot].devnum; /* * this branch is our 'one mirror IO has finished' event handler: */ update_head_pos(slot, r10_bio); if (uptodate) { /* * Set R10BIO_Uptodate in our master bio, so that * we will return a good error code to the higher * levels even if IO on some other mirrored buffer fails. * * The 'master' represents the composite IO operation to * user-side. So if something waits for IO, then it will * wait for the 'master' bio. */ set_bit(R10BIO_Uptodate, &r10_bio->state); raid_end_bio_io(r10_bio); } else { /* * oops, read error: */ char b[BDEVNAME_SIZE]; if (printk_ratelimit()) printk(KERN_ERR "raid10: %s: rescheduling sector %llu\n", bdevname(conf->mirrors[dev].rdev->bdev,b), (unsigned long long)r10_bio->sector); reschedule_retry(r10_bio); } rdev_dec_pending(conf->mirrors[dev].rdev, conf->mddev); } static void raid10_end_write_request(struct bio *bio, int error) { int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags); r10bio_t * r10_bio = (r10bio_t *)(bio->bi_private); int slot, dev; conf_t *conf = mddev_to_conf(r10_bio->mddev); for (slot = 0; slot < conf->copies; slot++) if (r10_bio->devs[slot].bio == bio) break; dev = r10_bio->devs[slot].devnum; /* * this branch is our 'one mirror IO has finished' event handler: */ if (!uptodate) { md_error(r10_bio->mddev, conf->mirrors[dev].rdev); /* an I/O failed, we can't clear the bitmap */ set_bit(R10BIO_Degraded, &r10_bio->state); } else /* * Set R10BIO_Uptodate in our master bio, so that * we will return a good error code for to the higher * levels even if IO on some other mirrored buffer fails. * * The 'master' represents the composite IO operation to * user-side. So if something waits for IO, then it will * wait for the 'master' bio. */ set_bit(R10BIO_Uptodate, &r10_bio->state); update_head_pos(slot, r10_bio); /* * * Let's see if all mirrored write operations have finished * already. */ if (atomic_dec_and_test(&r10_bio->remaining)) { /* clear the bitmap if all writes complete successfully */ bitmap_endwrite(r10_bio->mddev->bitmap, r10_bio->sector, r10_bio->sectors, !test_bit(R10BIO_Degraded, &r10_bio->state), 0); md_write_end(r10_bio->mddev); raid_end_bio_io(r10_bio); } rdev_dec_pending(conf->mirrors[dev].rdev, conf->mddev); } /* * RAID10 layout manager * Aswell as the chunksize and raid_disks count, there are two * parameters: near_copies and far_copies. * near_copies * far_copies must be <= raid_disks. * Normally one of these will be 1. * If both are 1, we get raid0. * If near_copies == raid_disks, we get raid1. * * Chunks are layed out in raid0 style with near_copies copies of the * first chunk, followed by near_copies copies of the next chunk and * so on. * If far_copies > 1, then after 1/far_copies of the array has been assigned * as described above, we start again with a device offset of near_copies. * So we effectively have another copy of the whole array further down all * the drives, but with blocks on different drives. * With this layout, and block is never stored twice on the one device. * * raid10_find_phys finds the sector offset of a given virtual sector * on each device that it is on. * * raid10_find_virt does the reverse mapping, from a device and a * sector offset to a virtual address */ static void raid10_find_phys(conf_t *conf, r10bio_t *r10bio) { int n,f; sector_t sector; sector_t chunk; sector_t stripe; int dev; int slot = 0; /* now calculate first sector/dev */ chunk = r10bio->sector >> conf->chunk_shift; sector = r10bio->sector & conf->chunk_mask; chunk *= conf->near_copies; stripe = chunk; dev = sector_div(stripe, conf->raid_disks); if (conf->far_offset) stripe *= conf->far_copies; sector += stripe << conf->chunk_shift; /* and calculate all the others */ for (n=0; n < conf->near_copies; n++) { int d = dev; sector_t s = sector; r10bio->devs[slot].addr = sector; r10bio->devs[slot].devnum = d; slot++; for (f = 1; f < conf->far_copies; f++) { d += conf->near_copies; if (d >= conf->raid_disks) d -= conf->raid_disks; s += conf->stride; r10bio->devs[slot].devnum = d; r10bio->devs[slot].addr = s; slot++; } dev++; if (dev >= conf->raid_disks) { dev = 0; sector += (conf->chunk_mask + 1); } } BUG_ON(slot != conf->copies); } static sector_t raid10_find_virt(conf_t *conf, sector_t sector, int dev) { sector_t offset, chunk, vchunk; offset = sector & conf->chunk_mask; if (conf->far_offset) { int fc; chunk = sector >> conf->chunk_shift; fc = sector_div(chunk, conf->far_copies); dev -= fc * conf->near_copies; if (dev < 0) dev += conf->raid_disks; } else { while (sector >= conf->stride) { sector -= conf->stride; if (dev < conf->near_copies) dev += conf->raid_disks - conf->near_copies; else dev -= conf->near_copies; } chunk = sector >> conf->chunk_shift; } vchunk = chunk * conf->raid_disks + dev; sector_div(vchunk, conf->near_copies); return (vchunk << conf->chunk_shift) + offset; } /** * raid10_mergeable_bvec -- tell bio layer if a two requests can be merged * @q: request queue * @bvm: properties of new bio * @biovec: the request that could be merged to it. * * Return amount of bytes we can accept at this offset * If near_copies == raid_disk, there are no striping issues, * but in that case, the function isn't called at all. */ static int raid10_mergeable_bvec(struct request_queue *q, struct bvec_merge_data *bvm, struct bio_vec *biovec) { mddev_t *mddev = q->queuedata; sector_t sector = bvm->bi_sector + get_start_sect(bvm->bi_bdev); int max; unsigned int chunk_sectors = mddev->chunk_size >> 9; unsigned int bio_sectors = bvm->bi_size >> 9; max = (chunk_sectors - ((sector & (chunk_sectors - 1)) + bio_sectors)) << 9; if (max < 0) max = 0; /* bio_add cannot handle a negative return */ if (max <= biovec->bv_len && bio_sectors == 0) return biovec->bv_len; else return max; } /* * This routine returns the disk from which the requested read should * be done. There is a per-array 'next expected sequential IO' sector * number - if this matches on the next IO then we use the last disk. * There is also a per-disk 'last know head position' sector that is * maintained from IRQ contexts, both the normal and the resync IO * completion handlers update this position correctly. If there is no * perfect sequential match then we pick the disk whose head is closest. * * If there are 2 mirrors in the same 2 devices, performance degrades * because position is mirror, not device based. * * The rdev for the device selected will have nr_pending incremented. */ /* * FIXME: possibly should rethink readbalancing and do it differently * depending on near_copies / far_copies geometry. */ static int read_balance(conf_t *conf, r10bio_t *r10_bio) { const unsigned long this_sector = r10_bio->sector; int disk, slot, nslot; const int sectors = r10_bio->sectors; sector_t new_distance, current_distance; mdk_rdev_t *rdev; raid10_find_phys(conf, r10_bio); rcu_read_lock(); /* * Check if we can balance. We can balance on the whole * device if no resync is going on (recovery is ok), or below * the resync window. We take the first readable disk when * above the resync window. */ if (conf->mddev->recovery_cp < MaxSector && (this_sector + sectors >= conf->next_resync)) { /* make sure that disk is operational */ slot = 0; disk = r10_bio->devs[slot].devnum; while ((rdev = rcu_dereference(conf->mirrors[disk].rdev)) == NULL || r10_bio->devs[slot].bio == IO_BLOCKED || !test_bit(In_sync, &rdev->flags)) { slot++; if (slot == conf->copies) { slot = 0; disk = -1; break; } disk = r10_bio->devs[slot].devnum; } goto rb_out; } /* make sure the disk is operational */ slot = 0; disk = r10_bio->devs[slot].devnum; while ((rdev=rcu_dereference(conf->mirrors[disk].rdev)) == NULL || r10_bio->devs[slot].bio == IO_BLOCKED || !test_bit(In_sync, &rdev->flags)) { slot ++; if (slot == conf->copies) { disk = -1; goto rb_out; } disk = r10_bio->devs[slot].devnum; } current_distance = abs(r10_bio->devs[slot].addr - conf->mirrors[disk].head_position); /* Find the disk whose head is closest, * or - for far > 1 - find the closest to partition beginning */ for (nslot = slot; nslot < conf->copies; nslot++) { int ndisk = r10_bio->devs[nslot].devnum; if ((rdev=rcu_dereference(conf->mirrors[ndisk].rdev)) == NULL || r10_bio->devs[nslot].bio == IO_BLOCKED || !test_bit(In_sync, &rdev->flags)) continue; /* This optimisation is debatable, and completely destroys * sequential read speed for 'far copies' arrays. So only * keep it for 'near' arrays, and review those later. */ if (conf->near_copies > 1 && !atomic_read(&rdev->nr_pending)) { disk = ndisk; slot = nslot; break; } /* for far > 1 always use the lowest address */ if (conf->far_copies > 1) new_distance = r10_bio->devs[nslot].addr; else new_distance = abs(r10_bio->devs[nslot].addr - conf->mirrors[ndisk].head_position); if (new_distance < current_distance) { current_distance = new_distance; disk = ndisk; slot = nslot; } } rb_out: r10_bio->read_slot = slot; /* conf->next_seq_sect = this_sector + sectors;*/ if (disk >= 0 && (rdev=rcu_dereference(conf->mirrors[disk].rdev))!= NULL) atomic_inc(&conf->mirrors[disk].rdev->nr_pending); else disk = -1; rcu_read_unlock(); return disk; } static void unplug_slaves(mddev_t *mddev) { conf_t *conf = mddev_to_conf(mddev); int i; rcu_read_lock(); for (i=0; i<mddev->raid_disks; i++) { mdk_rdev_t *rdev = rcu_dereference(conf->mirrors[i].rdev); if (rdev && !test_bit(Faulty, &rdev->flags) && atomic_read(&rdev->nr_pending)) { struct request_queue *r_queue = bdev_get_queue(rdev->bdev); atomic_inc(&rdev->nr_pending); rcu_read_unlock(); blk_unplug(r_queue); rdev_dec_pending(rdev, mddev); rcu_read_lock(); } } rcu_read_unlock(); } static void raid10_unplug(struct request_queue *q) { mddev_t *mddev = q->queuedata; unplug_slaves(q->queuedata); md_wakeup_thread(mddev->thread); } static int raid10_congested(void *data, int bits) { mddev_t *mddev = data; 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 = rcu_dereference(conf->mirrors[i].rdev); if (rdev && !test_bit(Faulty, &rdev->flags)) { struct request_queue *q = bdev_get_queue(rdev->bdev); ret |= bdi_congested(&q->backing_dev_info, bits); } } rcu_read_unlock(); return ret; } static int flush_pending_writes(conf_t *conf) { /* Any writes that have been queued but are awaiting * bitmap updates get flushed here. * We return 1 if any requests were actually submitted. */ int rv = 0; spin_lock_irq(&conf->device_lock); if (conf->pending_bio_list.head) { struct bio *bio; bio = bio_list_get(&conf->pending_bio_list); blk_remove_plug(conf->mddev->queue); 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; } rv = 1; } else spin_unlock_irq(&conf->device_lock); return rv; } /* 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. */ static void raise_barrier(conf_t *conf, int force) { BUG_ON(force && !conf->barrier); spin_lock_irq(&conf->resync_lock); /* Wait until no block IO is waiting (unless 'force') */ wait_event_lock_irq(conf->wait_barrier, force || !conf->nr_waiting, conf->resync_lock, raid10_unplug(conf->mddev->queue)); /* block any new IO from starting */ conf->barrier++; /* No wait for all pending IO to complete */ wait_event_lock_irq(conf->wait_barrier, !conf->nr_pending && conf->barrier < RESYNC_DEPTH, conf->resync_lock, raid10_unplug(conf->mddev->queue)); spin_unlock_irq(&conf->resync_lock); } static void lower_barrier(conf_t *conf) { unsigned long flags; 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_event_lock_irq(conf->wait_barrier, !conf->barrier, conf->resync_lock, raid10_unplug(conf->mddev->queue)); 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 quiet. * 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); raid10_unplug(conf->mddev->queue); })); 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); } static int make_request(struct request_queue *q, struct bio * bio) { mddev_t *mddev = q->queuedata; conf_t *conf = mddev_to_conf(mddev); mirror_info_t *mirror; r10bio_t *r10_bio; struct bio *read_bio; int cpu; int i; int chunk_sects = conf->chunk_mask + 1; const int rw = bio_data_dir(bio); const int do_sync = bio_sync(bio); struct bio_list bl; unsigned long flags; mdk_rdev_t *blocked_rdev; if (unlikely(bio_barrier(bio))) { bio_endio(bio, -EOPNOTSUPP); return 0; } /* If this request crosses a chunk boundary, we need to * split it. This will only happen for 1 PAGE (or less) requests. */ if (unlikely( (bio->bi_sector & conf->chunk_mask) + (bio->bi_size >> 9) > chunk_sects && conf->near_copies < conf->raid_disks)) { struct bio_pair *bp; /* Sanity check -- queue functions should prevent this happening */ if (bio->bi_vcnt != 1 || bio->bi_idx != 0) goto bad_map; /* This is a one page bio that upper layers * refuse to split for us, so we need to split it. */ bp = bio_split(bio, chunk_sects - (bio->bi_sector & (chunk_sects - 1)) ); if (make_request(q, &bp->bio1)) generic_make_request(&bp->bio1); if (make_request(q, &bp->bio2)) generic_make_request(&bp->bio2); bio_pair_release(bp); return 0; bad_map: printk("raid10_make_request bug: can't convert block across chunks" " or bigger than %dk %llu %d\n", chunk_sects/2, (unsigned long long)bio->bi_sector, bio->bi_size >> 10); bio_io_error(bio); return 0; } md_write_start(mddev, bio); /* * 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. */ wait_barrier(conf); cpu = part_stat_lock(); part_stat_inc(cpu, &mddev->gendisk->part0, ios[rw]); part_stat_add(cpu, &mddev->gendisk->part0, sectors[rw], bio_sectors(bio)); part_stat_unlock(); r10_bio = mempool_alloc(conf->r10bio_pool, GFP_NOIO); r10_bio->master_bio = bio; r10_bio->sectors = bio->bi_size >> 9; r10_bio->mddev = mddev; r10_bio->sector = bio->bi_sector; r10_bio->state = 0; if (rw == READ) { /* * read balancing logic: */ int disk = read_balance(conf, r10_bio); int slot = r10_bio->read_slot; if (disk < 0) { raid_end_bio_io(r10_bio); return 0; } mirror = conf->mirrors + disk; read_bio = bio_clone(bio, GFP_NOIO); r10_bio->devs[slot].bio = read_bio; read_bio->bi_sector = r10_bio->devs[slot].addr + mirror->rdev->data_offset; read_bio->bi_bdev = mirror->rdev->bdev; read_bio->bi_end_io = raid10_end_read_request; read_bio->bi_rw = READ | do_sync; read_bio->bi_private = r10_bio; generic_make_request(read_bio); return 0; } /* * WRITE: */ /* first select target devices under rcu_lock and * inc refcount on their rdev. Record them by setting * bios[x] to bio */ raid10_find_phys(conf, r10_bio); retry_write: blocked_rdev = NULL; rcu_read_lock(); for (i = 0; i < conf->copies; i++) { int d = r10_bio->devs[i].devnum; mdk_rdev_t *rdev = rcu_dereference(conf->mirrors[d].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); r10_bio->devs[i].bio = bio; } else { r10_bio->devs[i].bio = NULL; set_bit(R10BIO_Degraded, &r10_bio->state); } } rcu_read_unlock(); if (unlikely(blocked_rdev)) { /* Have to wait for this device to get unblocked, then retry */ int j; int d; for (j = 0; j < i; j++) if (r10_bio->devs[j].bio) { d = r10_bio->devs[j].devnum; rdev_dec_pending(conf->mirrors[d].rdev, mddev); } allow_barrier(conf); md_wait_for_blocked_rdev(blocked_rdev, mddev); wait_barrier(conf); goto retry_write; } atomic_set(&r10_bio->remaining, 0); bio_list_init(&bl); for (i = 0; i < conf->copies; i++) { struct bio *mbio; int d = r10_bio->devs[i].devnum; if (!r10_bio->devs[i].bio) continue; mbio = bio_clone(bio, GFP_NOIO); r10_bio->devs[i].bio = mbio; mbio->bi_sector = r10_bio->devs[i].addr+ conf->mirrors[d].rdev->data_offset; mbio->bi_bdev = conf->mirrors[d].rdev->bdev; mbio->bi_end_io = raid10_end_write_request; mbio->bi_rw = WRITE | do_sync; mbio->bi_private = r10_bio; atomic_inc(&r10_bio->remaining); bio_list_add(&bl, mbio); } if (unlikely(!atomic_read(&r10_bio->remaining))) { /* the array is dead */ md_write_end(mddev); raid_end_bio_io(r10_bio); return 0; } bitmap_startwrite(mddev->bitmap, bio->bi_sector, r10_bio->sectors, 0); spin_lock_irqsave(&conf->device_lock, flags); bio_list_merge(&conf->pending_bio_list, &bl); blk_plug_device(mddev->queue); spin_unlock_irqrestore(&conf->device_lock, flags); /* In case raid10d snuck in to freeze_array */ wake_up(&conf->wait_barrier); if (do_sync) md_wakeup_thread(mddev->thread); return 0; } static void status(struct seq_file *seq, mddev_t *mddev) { conf_t *conf = mddev_to_conf(mddev); int i; if (conf->near_copies < conf->raid_disks) seq_printf(seq, " %dK chunks", mddev->chunk_size/1024); if (conf->near_copies > 1) seq_printf(seq, " %d near-copies", conf->near_copies); if (conf->far_copies > 1) { if (conf->far_offset) seq_printf(seq, " %d offset-copies", conf->far_copies); else seq_printf(seq, " %d far-copies", conf->far_copies); } seq_printf(seq, " [%d/%d] [", conf->raid_disks, conf->raid_disks - mddev->degraded); for (i = 0; i < conf->raid_disks; i++) seq_printf(seq, "%s", conf->mirrors[i].rdev && test_bit(In_sync, &conf->mirrors[i].rdev->flags) ? "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 (test_bit(In_sync, &rdev->flags) && conf->raid_disks-mddev->degraded == 1) /* * Don't fail the drive, just return an IO error. * The test should really be more sophisticated than * "working_disks == 1", but it isn't critical, and * can wait until we do more sophisticated "is the drive * really dead" tests... */ return; if (test_and_clear_bit(In_sync, &rdev->flags)) { unsigned long flags; spin_lock_irqsave(&conf->device_lock, flags); mddev->degraded++; spin_unlock_irqrestore(&conf->device_lock, flags); /* * if recovery is running, make sure it aborts. */ set_bit(MD_RECOVERY_INTR, &mddev->recovery); } set_bit(Faulty, &rdev->flags); set_bit(MD_CHANGE_DEVS, &mddev->flags); printk(KERN_ALERT "raid10: Disk failure on %s, disabling device.\n" "raid10: Operation continuing on %d devices.\n", bdevname(rdev->bdev,b), conf->raid_disks - mddev->degraded); } static void print_conf(conf_t *conf) { int i; mirror_info_t *tmp; printk("RAID10 conf printout:\n"); if (!conf) { printk("(!conf)\n"); return; } printk(" --- wd:%d rd:%d\n", conf->raid_disks - conf->mddev->degraded, 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, !test_bit(In_sync, &tmp->rdev->flags), !test_bit(Faulty, &tmp->rdev->flags), bdevname(tmp->rdev->bdev,b)); } } static void close_sync(conf_t *conf) { wait_barrier(conf); allow_barrier(conf); mempool_destroy(conf->r10buf_pool); conf->r10buf_pool = NULL; } /* check if there are enough drives for * every block to appear on atleast one */ static int enough(conf_t *conf) { int first = 0; do { int n = conf->copies; int cnt = 0; while (n--) { if (conf->mirrors[first].rdev) cnt++; first = (first+1) % conf->raid_disks; } if (cnt == 0) return 0; } while (first != 0); return 1; } static int raid10_spare_active(mddev_t *mddev) { int i; conf_t *conf = mddev->private; mirror_info_t *tmp; /* * Find all non-in_sync disks within the RAID10 configuration * and mark them in_sync */ for (i = 0; i < conf->raid_disks; i++) { tmp = conf->mirrors + i; if (tmp->rdev && !test_bit(Faulty, &tmp->rdev->flags) && !test_and_set_bit(In_sync, &tmp->rdev->flags)) { unsigned long flags; spin_lock_irqsave(&conf->device_lock, flags); mddev->degraded--; spin_unlock_irqrestore(&conf->device_lock, flags); } } print_conf(conf); return 0; } static int raid10_add_disk(mddev_t *mddev, mdk_rdev_t *rdev) { conf_t *conf = mddev->private; int err = -EEXIST; int mirror; mirror_info_t *p; int first = 0; int last = mddev->raid_disks - 1; if (mddev->recovery_cp < MaxSector) /* only hot-add to in-sync arrays, as recovery is * very different from resync */ return -EBUSY; if (!enough(conf)) return -EINVAL; if (rdev->raid_disk) first = last = rdev->raid_disk; if (rdev->saved_raid_disk >= 0 && rdev->saved_raid_disk >= first && conf->mirrors[rdev->saved_raid_disk].rdev == NULL) mirror = rdev->saved_raid_disk; else mirror = first; for ( ; mirror <= last ; mirror++) if ( !(p=conf->mirrors+mirror)->rdev) { blk_queue_stack_limits(mddev->queue, rdev->bdev->bd_disk->queue); /* as we don't honour merge_bvec_fn, we must never risk * violating it, so limit ->max_sector to one PAGE, as * a one page request is never in violation. */ if (rdev->bdev->bd_disk->queue->merge_bvec_fn && mddev->queue->max_sectors > (PAGE_SIZE>>9)) mddev->queue->max_sectors = (PAGE_SIZE>>9); p->head_position = 0; rdev->raid_disk = mirror; err = 0; if (rdev->saved_raid_disk != mirror) conf->fullsync = 1; rcu_assign_pointer(p->rdev, rdev); break; } print_conf(conf); return err; } static int raid10_remove_disk(mddev_t *mddev, int number) { conf_t *conf = mddev->private; int err = 0; mdk_rdev_t *rdev; mirror_info_t *p = conf->mirrors+ number; print_conf(conf); rdev = p->rdev; if (rdev) { if (test_bit(In_sync, &rdev->flags) || atomic_read(&rdev->nr_pending)) { err = -EBUSY; goto abort; } /* Only remove faulty devices in recovery * is not possible. */ if (!test_bit(Faulty, &rdev->flags) && enough(conf)) { 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; } } abort: print_conf(conf); return err; } static void end_sync_read(struct bio *bio, int error) { r10bio_t * r10_bio = (r10bio_t *)(bio->bi_private); conf_t *conf = mddev_to_conf(r10_bio->mddev); int i,d; for (i=0; i<conf->copies; i++) if (r10_bio->devs[i].bio == bio) break; BUG_ON(i == conf->copies); update_head_pos(i, r10_bio); d = r10_bio->devs[i].devnum; if (test_bit(BIO_UPTODATE, &bio->bi_flags)) set_bit(R10BIO_Uptodate, &r10_bio->state); else { atomic_add(r10_bio->sectors, &conf->mirrors[d].rdev->corrected_errors); if (!test_bit(MD_RECOVERY_SYNC, &conf->mddev->recovery)) md_error(r10_bio->mddev, conf->mirrors[d].rdev); } /* for reconstruct, we always reschedule after a read. * for resync, only after all reads */ if (test_bit(R10BIO_IsRecover, &r10_bio->state) || atomic_dec_and_test(&r10_bio->remaining)) { /* we have read all the blocks, * do the comparison in process context in raid10d */ reschedule_retry(r10_bio); } rdev_dec_pending(conf->mirrors[d].rdev, conf->mddev); } static void end_sync_write(struct bio *bio, int error) { int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags); r10bio_t * r10_bio = (r10bio_t *)(bio->bi_private); mddev_t *mddev = r10_bio->mddev; conf_t *conf = mddev_to_conf(mddev); int i,d; for (i = 0; i < conf->copies; i++) if (r10_bio->devs[i].bio == bio) break; d = r10_bio->devs[i].devnum; if (!uptodate) md_error(mddev, conf->mirrors[d].rdev); update_head_pos(i, r10_bio); while (atomic_dec_and_test(&r10_bio->remaining)) { if (r10_bio->master_bio == NULL) { /* the primary of several recovery bios */ md_done_sync(mddev, r10_bio->sectors, 1); put_buf(r10_bio); break; } else { r10bio_t *r10_bio2 = (r10bio_t *)r10_bio->master_bio; put_buf(r10_bio); r10_bio = r10_bio2; } } rdev_dec_pending(conf->mirrors[d].rdev, mddev); } /* * Note: sync and recover and handled very differently for raid10 * This code is for resync. * For resync, we read through virtual addresses and read all blocks. * If there is any error, we schedule a write. The lowest numbered * drive is authoritative. * However requests come for physical address, so we need to map. * For every physical address there are raid_disks/copies virtual addresses, * which is always are least one, but is not necessarly an integer. * This means that a physical address can span multiple chunks, so we may * have to submit multiple io requests for a single sync request. */ /* * We check if all blocks are in-sync and only write to blocks that * aren't in sync */ static void sync_request_write(mddev_t *mddev, r10bio_t *r10_bio) { conf_t *conf = mddev_to_conf(mddev); int i, first; struct bio *tbio, *fbio; atomic_set(&r10_bio->remaining, 1); /* find the first device with a block */ for (i=0; i<conf->copies; i++) if (test_bit(BIO_UPTODATE, &r10_bio->devs[i].bio->bi_flags)) break; if (i == conf->copies) goto done; first = i; fbio = r10_bio->devs[i].bio; /* now find blocks with errors */ for (i=0 ; i < conf->copies ; i++) { int j, d; int vcnt = r10_bio->sectors >> (PAGE_SHIFT-9); tbio = r10_bio->devs[i].bio; if (tbio->bi_end_io != end_sync_read) continue; if (i == first) continue; if (test_bit(BIO_UPTODATE, &r10_bio->devs[i].bio->bi_flags)) { /* We know that the bi_io_vec layout is the same for * both 'first' and 'i', so we just compare them. * All vec entries are PAGE_SIZE; */ for (j = 0; j < vcnt; j++) if (memcmp(page_address(fbio->bi_io_vec[j].bv_page), page_address(tbio->bi_io_vec[j].bv_page), PAGE_SIZE)) break; if (j == vcnt) continue; mddev->resync_mismatches += r10_bio->sectors; } if (test_bit(MD_RECOVERY_CHECK, &mddev->recovery)) /* Don't fix anything. */ continue; /* Ok, we need to write this bio * First we need to fixup bv_offset, bv_len and * bi_vecs, as the read request might have corrupted these */ tbio->bi_vcnt = vcnt; tbio->bi_size = r10_bio->sectors << 9; tbio->bi_idx = 0; tbio->bi_phys_segments = 0; tbio->bi_flags &= ~(BIO_POOL_MASK - 1); tbio->bi_flags |= 1 << BIO_UPTODATE; tbio->bi_next = NULL; tbio->bi_rw = WRITE; tbio->bi_private = r10_bio; tbio->bi_sector = r10_bio->devs[i].addr; for (j=0; j < vcnt ; j++) { tbio->bi_io_vec[j].bv_offset = 0; tbio->bi_io_vec[j].bv_len = PAGE_SIZE; memcpy(page_address(tbio->bi_io_vec[j].bv_page), page_address(fbio->bi_io_vec[j].bv_page), PAGE_SIZE); } tbio->bi_end_io = end_sync_write; d = r10_bio->devs[i].devnum; atomic_inc(&conf->mirrors[d].rdev->nr_pending); atomic_inc(&r10_bio->remaining); md_sync_acct(conf->mirrors[d].rdev->bdev, tbio->bi_size >> 9); tbio->bi_sector += conf->mirrors[d].rdev->data_offset; tbio->bi_bdev = conf->mirrors[d].rdev->bdev; generic_make_request(tbio); } done: if (atomic_dec_and_test(&r10_bio->remaining)) { md_done_sync(mddev, r10_bio->sectors, 1); put_buf(r10_bio); } } /* * Now for the recovery code. * Recovery happens across physical sectors. * We recover all non-is_sync drives by finding the virtual address of * each, and then choose a working drive that also has that virt address. * There is a separate r10_bio for each non-in_sync drive. * Only the first two slots are in use. The first for reading, * The second for writing. * */ static void recovery_request_write(mddev_t *mddev, r10bio_t *r10_bio) { conf_t *conf = mddev_to_conf(mddev); int i, d; struct bio *bio, *wbio; /* move the pages across to the second bio * and submit the write request */ bio = r10_bio->devs[0].bio; wbio = r10_bio->devs[1].bio; for (i=0; i < wbio->bi_vcnt; i++) { struct page *p = bio->bi_io_vec[i].bv_page; bio->bi_io_vec[i].bv_page = wbio->bi_io_vec[i].bv_page; wbio->bi_io_vec[i].bv_page = p; } d = r10_bio->devs[1].devnum; atomic_inc(&conf->mirrors[d].rdev->nr_pending); md_sync_acct(conf->mirrors[d].rdev->bdev, wbio->bi_size >> 9); if (test_bit(R10BIO_Uptodate, &r10_bio->state)) generic_make_request(wbio); else bio_endio(wbio, -EIO); } /* * 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 synchronising. */ static void fix_read_error(conf_t *conf, mddev_t *mddev, r10bio_t *r10_bio) { int sect = 0; /* Offset from r10_bio->sector */ int sectors = r10_bio->sectors; mdk_rdev_t*rdev; while(sectors) { int s = sectors; int sl = r10_bio->read_slot; int success = 0; int start; if (s > (PAGE_SIZE>>9)) s = PAGE_SIZE >> 9; rcu_read_lock(); do { int d = r10_bio->devs[sl].devnum; rdev = rcu_dereference(conf->mirrors[d].rdev); if (rdev && test_bit(In_sync, &rdev->flags)) { atomic_inc(&rdev->nr_pending); rcu_read_unlock(); success = sync_page_io(rdev->bdev, r10_bio->devs[sl].addr + sect + rdev->data_offset, s<<9, conf->tmppage, READ); rdev_dec_pending(rdev, mddev); rcu_read_lock(); if (success) break; } sl++; if (sl == conf->copies) sl = 0; } while (!success && sl != r10_bio->read_slot); rcu_read_unlock(); if (!success) { /* Cannot read from anywhere -- bye bye array */ int dn = r10_bio->devs[r10_bio->read_slot].devnum; md_error(mddev, conf->mirrors[dn].rdev); break; } start = sl; /* write it back and re-read */ rcu_read_lock(); while (sl != r10_bio->read_slot) { int d; if (sl==0) sl = conf->copies; sl--; d = r10_bio->devs[sl].devnum; rdev = rcu_dereference(conf->mirrors[d].rdev); if (rdev && test_bit(In_sync, &rdev->flags)) { atomic_inc(&rdev->nr_pending); rcu_read_unlock(); atomic_add(s, &rdev->corrected_errors); if (sync_page_io(rdev->bdev, r10_bio->devs[sl].addr + sect + rdev->data_offset, s<<9, conf->tmppage, WRITE) == 0) /* Well, this device is dead */ md_error(mddev, rdev); rdev_dec_pending(rdev, mddev); rcu_read_lock(); } } sl = start; while (sl != r10_bio->read_slot) { int d; if (sl==0) sl = conf->copies; sl--; d = r10_bio->devs[sl].devnum; rdev = rcu_dereference(conf->mirrors[d].rdev); if (rdev && test_bit(In_sync, &rdev->flags)) { char b[BDEVNAME_SIZE]; atomic_inc(&rdev->nr_pending); rcu_read_unlock(); if (sync_page_io(rdev->bdev, r10_bio->devs[sl].addr + sect + rdev->data_offset, s<<9, conf->tmppage, READ) == 0) /* Well, this device is dead */ md_error(mddev, rdev); else printk(KERN_INFO "raid10:%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)); rdev_dec_pending(rdev, mddev); rcu_read_lock(); } } rcu_read_unlock(); sectors -= s; sect += s; } } static void raid10d(mddev_t *mddev) { r10bio_t *r10_bio; struct bio *bio; unsigned long flags; conf_t *conf = mddev_to_conf(mddev); struct list_head *head = &conf->retry_list; int unplug=0; mdk_rdev_t *rdev; md_check_recovery(mddev); for (;;) { char b[BDEVNAME_SIZE]; unplug += flush_pending_writes(conf); spin_lock_irqsave(&conf->device_lock, flags); if (list_empty(head)) { spin_unlock_irqrestore(&conf->device_lock, flags); break; } r10_bio = list_entry(head->prev, r10bio_t, retry_list); list_del(head->prev); conf->nr_queued--; spin_unlock_irqrestore(&conf->device_lock, flags); mddev = r10_bio->mddev; conf = mddev_to_conf(mddev); if (test_bit(R10BIO_IsSync, &r10_bio->state)) { sync_request_write(mddev, r10_bio); unplug = 1; } else if (test_bit(R10BIO_IsRecover, &r10_bio->state)) { recovery_request_write(mddev, r10_bio); unplug = 1; } else { int mirror; /* 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, mddev, r10_bio); unfreeze_array(conf); } bio = r10_bio->devs[r10_bio->read_slot].bio; r10_bio->devs[r10_bio->read_slot].bio = mddev->ro ? IO_BLOCKED : NULL; mirror = read_balance(conf, r10_bio); if (mirror == -1) { printk(KERN_ALERT "raid10: %s: unrecoverable I/O" " read error for block %llu\n", bdevname(bio->bi_bdev,b), (unsigned long long)r10_bio->sector); raid_end_bio_io(r10_bio); bio_put(bio); } else { const int do_sync = bio_sync(r10_bio->master_bio); bio_put(bio); rdev = conf->mirrors[mirror].rdev; if (printk_ratelimit()) printk(KERN_ERR "raid10: %s: redirecting sector %llu to" " another mirror\n", bdevname(rdev->bdev,b), (unsigned long long)r10_bio->sector); bio = bio_clone(r10_bio->master_bio, GFP_NOIO); r10_bio->devs[r10_bio->read_slot].bio = bio; bio->bi_sector = r10_bio->devs[r10_bio->read_slot].addr + rdev->data_offset; bio->bi_bdev = rdev->bdev; bio->bi_rw = READ | do_sync; bio->bi_private = r10_bio; bio->bi_end_io = raid10_end_read_request; unplug = 1; generic_make_request(bio); } } } if (unplug) unplug_slaves(mddev); } static int init_resync(conf_t *conf) { int buffs; buffs = RESYNC_WINDOW / RESYNC_BLOCK_SIZE; BUG_ON(conf->r10buf_pool); conf->r10buf_pool = mempool_create(buffs, r10buf_pool_alloc, r10buf_pool_free, conf); if (!conf->r10buf_pool) return -ENOMEM; conf->next_resync = 0; return 0; } /* * perform a "sync" on one "block" * * We need to make sure that no normal I/O request - particularly write * requests - conflict with active sync requests. * * This is achieved by tracking pending requests and a 'barrier' concept * that can be installed to exclude normal IO requests. * * Resync and recovery are handled very differently. * We differentiate by looking at MD_RECOVERY_SYNC in mddev->recovery. * * For resync, we iterate over virtual addresses, read all copies, * and update if there are differences. If only one copy is live, * skip it. * For recovery, we iterate over physical addresses, read a good * value for each non-in_sync drive, and over-write. * * So, for recovery we may have several outstanding complex requests for a * given address, one for each out-of-sync device. We model this by allocating * a number of r10_bio structures, one for each out-of-sync device. * As we setup these structures, we collect all bio's together into a list * which we then process collectively to add pages, and then process again * to pass to generic_make_request. * * The r10_bio structures are linked using a borrowed master_bio pointer. * This link is counted in ->remaining. When the r10_bio that points to NULL * has its remaining count decremented to 0, the whole complex operation * is complete. * */ static sector_t sync_request(mddev_t *mddev, sector_t sector_nr, int *skipped, int go_faster) { conf_t *conf = mddev_to_conf(mddev); r10bio_t *r10_bio; struct bio *biolist = NULL, *bio; sector_t max_sector, nr_sectors; int disk; int i; int max_sync; int sync_blocks; sector_t sectors_skipped = 0; int chunks_skipped = 0; if (!conf->r10buf_pool) if (init_resync(conf)) return 0; skipped: max_sector = mddev->size << 1; if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) max_sector = mddev->resync_max_sectors; if (sector_nr >= max_sector) { /* If we aborted, we need to abort the * sync on the 'current' bitmap chucks (there can * be several when recovering multiple devices). * as we may have started syncing it but not finished. * We can find the current address in * mddev->curr_resync, but for recovery, * we need to convert that to several * virtual addresses. */ if (mddev->curr_resync < max_sector) { /* aborted */ if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) bitmap_end_sync(mddev->bitmap, mddev->curr_resync, &sync_blocks, 1); else for (i=0; i<conf->raid_disks; i++) { sector_t sect = raid10_find_virt(conf, mddev->curr_resync, i); bitmap_end_sync(mddev->bitmap, sect, &sync_blocks, 1); } } else /* completed sync */ conf->fullsync = 0; bitmap_close_sync(mddev->bitmap); close_sync(conf); *skipped = 1; return sectors_skipped; } if (chunks_skipped >= conf->raid_disks) { /* if there has been nothing to do on any drive, * then there is nothing to do at all.. */ *skipped = 1; return (max_sector - sector_nr) + sectors_skipped; } if (max_sector > mddev->resync_max) max_sector = mddev->resync_max; /* Don't do IO beyond here */ /* make sure whole request will fit in a chunk - if chunks * are meaningful */ if (conf->near_copies < conf->raid_disks && max_sector > (sector_nr | conf->chunk_mask)) max_sector = (sector_nr | conf->chunk_mask) + 1; /* * If there is non-resync activity waiting for us then * put in a delay to throttle resync. */ if (!go_faster && conf->nr_waiting) msleep_interruptible(1000); bitmap_cond_end_sync(mddev->bitmap, sector_nr); /* Again, very different code for resync and recovery. * Both must result in an r10bio with a list of bios that * have bi_end_io, bi_sector, bi_bdev set, * and bi_private set to the r10bio. * For recovery, we may actually create several r10bios * with 2 bios in each, that correspond to the bios in the main one. * In this case, the subordinate r10bios link back through a * borrowed master_bio pointer, and the counter in the master * includes a ref from each subordinate. */ /* First, we decide what to do and set ->bi_end_io * To end_sync_read if we want to read, and * end_sync_write if we will want to write. */ max_sync = RESYNC_PAGES << (PAGE_SHIFT-9); if (!test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) { /* recovery... the complicated one */ int i, j, k; r10_bio = NULL; for (i=0 ; i<conf->raid_disks; i++) if (conf->mirrors[i].rdev && !test_bit(In_sync, &conf->mirrors[i].rdev->flags)) { int still_degraded = 0; /* want to reconstruct this device */ r10bio_t *rb2 = r10_bio; sector_t sect = raid10_find_virt(conf, sector_nr, i); int must_sync; /* Unless we are doing a full sync, we only need * to recover the block if it is set in the bitmap */ must_sync = bitmap_start_sync(mddev->bitmap, sect, &sync_blocks, 1); if (sync_blocks < max_sync) max_sync = sync_blocks; if (!must_sync && !conf->fullsync) { /* yep, skip the sync_blocks here, but don't assume * that there will never be anything to do here */ chunks_skipped = -1; continue; } r10_bio = mempool_alloc(conf->r10buf_pool, GFP_NOIO); raise_barrier(conf, rb2 != NULL); atomic_set(&r10_bio->remaining, 0); r10_bio->master_bio = (struct bio*)rb2; if (rb2) atomic_inc(&rb2->remaining); r10_bio->mddev = mddev; set_bit(R10BIO_IsRecover, &r10_bio->state); r10_bio->sector = sect; raid10_find_phys(conf, r10_bio); /* Need to check if this section will still be * degraded */ for (j=0; j<conf->copies;j++) { int d = r10_bio->devs[j].devnum; if (conf->mirrors[d].rdev == NULL || test_bit(Faulty, &conf->mirrors[d].rdev->flags)) { still_degraded = 1; break; } } must_sync = bitmap_start_sync(mddev->bitmap, sect, &sync_blocks, still_degraded); for (j=0; j<conf->copies;j++) { int d = r10_bio->devs[j].devnum; if (conf->mirrors[d].rdev && test_bit(In_sync, &conf->mirrors[d].rdev->flags)) { /* This is where we read from */ bio = r10_bio->devs[0].bio; bio->bi_next = biolist; biolist = bio; bio->bi_private = r10_bio; bio->bi_end_io = end_sync_read; bio->bi_rw = READ; bio->bi_sector = r10_bio->devs[j].addr + conf->mirrors[d].rdev->data_offset; bio->bi_bdev = conf->mirrors[d].rdev->bdev; atomic_inc(&conf->mirrors[d].rdev->nr_pending); atomic_inc(&r10_bio->remaining); /* and we write to 'i' */ for (k=0; k<conf->copies; k++) if (r10_bio->devs[k].devnum == i) break; BUG_ON(k == conf->copies); bio = r10_bio->devs[1].bio; bio->bi_next = biolist; biolist = bio; bio->bi_private = r10_bio; bio->bi_end_io = end_sync_write; bio->bi_rw = WRITE; bio->bi_sector = r10_bio->devs[k].addr + conf->mirrors[i].rdev->data_offset; bio->bi_bdev = conf->mirrors[i].rdev->bdev; r10_bio->devs[0].devnum = d; r10_bio->devs[1].devnum = i; break; } } if (j == conf->copies) { /* Cannot recover, so abort the recovery */ put_buf(r10_bio); if (rb2) atomic_dec(&rb2->remaining); r10_bio = rb2; if (!test_and_set_bit(MD_RECOVERY_INTR, &mddev->recovery)) printk(KERN_INFO "raid10: %s: insufficient working devices for recovery.\n", mdname(mddev)); break; } } if (biolist == NULL) { while (r10_bio) { r10bio_t *rb2 = r10_bio; r10_bio = (r10bio_t*) rb2->master_bio; rb2->master_bio = NULL; put_buf(rb2); } goto giveup; } } else { /* resync. Schedule a read for every block at this virt offset */ int count = 0; if (!bitmap_start_sync(mddev->bitmap, sector_nr, &sync_blocks, mddev->degraded) && !conf->fullsync && !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery)) { /* We can skip this block */ *skipped = 1; return sync_blocks + sectors_skipped; } if (sync_blocks < max_sync) max_sync = sync_blocks; r10_bio = mempool_alloc(conf->r10buf_pool, GFP_NOIO); r10_bio->mddev = mddev; atomic_set(&r10_bio->remaining, 0); raise_barrier(conf, 0); conf->next_resync = sector_nr; r10_bio->master_bio = NULL; r10_bio->sector = sector_nr; set_bit(R10BIO_IsSync, &r10_bio->state); raid10_find_phys(conf, r10_bio); r10_bio->sectors = (sector_nr | conf->chunk_mask) - sector_nr +1; for (i=0; i<conf->copies; i++) { int d = r10_bio->devs[i].devnum; bio = r10_bio->devs[i].bio; bio->bi_end_io = NULL; clear_bit(BIO_UPTODATE, &bio->bi_flags); if (conf->mirrors[d].rdev == NULL || test_bit(Faulty, &conf->mirrors[d].rdev->flags)) continue; atomic_inc(&conf->mirrors[d].rdev->nr_pending); atomic_inc(&r10_bio->remaining); bio->bi_next = biolist; biolist = bio; bio->bi_private = r10_bio; bio->bi_end_io = end_sync_read; bio->bi_rw = READ; bio->bi_sector = r10_bio->devs[i].addr + conf->mirrors[d].rdev->data_offset; bio->bi_bdev = conf->mirrors[d].rdev->bdev; count++; } if (count < 2) { for (i=0; i<conf->copies; i++) { int d = r10_bio->devs[i].devnum; if (r10_bio->devs[i].bio->bi_end_io) rdev_dec_pending(conf->mirrors[d].rdev, mddev); } put_buf(r10_bio); biolist = NULL; goto giveup; } } for (bio = biolist; bio ; bio=bio->bi_next) { bio->bi_flags &= ~(BIO_POOL_MASK - 1); if (bio->bi_end_io) bio->bi_flags |= 1 << BIO_UPTODATE; bio->bi_vcnt = 0; bio->bi_idx = 0; bio->bi_phys_segments = 0; bio->bi_size = 0; } nr_sectors = 0; if (sector_nr + max_sync < max_sector) max_sector = sector_nr + max_sync; do { struct page *page; int len = PAGE_SIZE; disk = 0; if (sector_nr + (len>>9) > max_sector) len = (max_sector - sector_nr) << 9; if (len == 0) break; for (bio= biolist ; bio ; bio=bio->bi_next) { page = bio->bi_io_vec[bio->bi_vcnt].bv_page; if (bio_add_page(bio, page, len, 0) == 0) { /* stop here */ struct bio *bio2; bio->bi_io_vec[bio->bi_vcnt].bv_page = page; for (bio2 = biolist; bio2 && bio2 != bio; bio2 = bio2->bi_next) { /* remove last page from this bio */ bio2->bi_vcnt--; bio2->bi_size -= len; bio2->bi_flags &= ~(1<< BIO_SEG_VALID); } goto bio_full; } disk = i; } nr_sectors += len>>9; sector_nr += len>>9; } while (biolist->bi_vcnt < RESYNC_PAGES); bio_full: r10_bio->sectors = nr_sectors; while (biolist) { bio = biolist; biolist = biolist->bi_next; bio->bi_next = NULL; r10_bio = bio->bi_private; r10_bio->sectors = nr_sectors; if (bio->bi_end_io == end_sync_read) { md_sync_acct(bio->bi_bdev, nr_sectors); generic_make_request(bio); } } if (sectors_skipped) /* pretend they weren't skipped, it makes * no important difference in this case */ md_done_sync(mddev, sectors_skipped, 1); return sectors_skipped + nr_sectors; giveup: /* There is nowhere to write, so all non-sync * drives must be failed, so try the next chunk... */ { sector_t sec = max_sector - sector_nr; sectors_skipped += sec; chunks_skipped ++; sector_nr = max_sector; goto skipped; } } static int run(mddev_t *mddev) { conf_t *conf; int i, disk_idx; mirror_info_t *disk; mdk_rdev_t *rdev; struct list_head *tmp; int nc, fc, fo; sector_t stride, size; if (mddev->chunk_size == 0) { printk(KERN_ERR "md/raid10: non-zero chunk size required.\n"); return -EINVAL; } nc = mddev->layout & 255; fc = (mddev->layout >> 8) & 255; fo = mddev->layout & (1<<16); if ((nc*fc) <2 || (nc*fc) > mddev->raid_disks || (mddev->layout >> 17)) { printk(KERN_ERR "raid10: %s: unsupported raid10 layout: 0x%8x\n", mdname(mddev), mddev->layout); goto out; } /* * copy the already verified devices into our private RAID10 * bookkeeping area. [whatever we allocate in run(), * should be freed in stop()] */ conf = kzalloc(sizeof(conf_t), GFP_KERNEL); mddev->private = conf; if (!conf) { printk(KERN_ERR "raid10: couldn't allocate memory for %s\n", mdname(mddev)); goto out; } conf->mirrors = kzalloc(sizeof(struct mirror_info)*mddev->raid_disks, GFP_KERNEL); if (!conf->mirrors) { printk(KERN_ERR "raid10: couldn't allocate memory for %s\n", mdname(mddev)); goto out_free_conf; } conf->tmppage = alloc_page(GFP_KERNEL); if (!conf->tmppage) goto out_free_conf; conf->mddev = mddev; conf->raid_disks = mddev->raid_disks; conf->near_copies = nc; conf->far_copies = fc; conf->copies = nc*fc; conf->far_offset = fo; conf->chunk_mask = (sector_t)(mddev->chunk_size>>9)-1; conf->chunk_shift = ffz(~mddev->chunk_size) - 9; size = mddev->size >> (conf->chunk_shift-1); sector_div(size, fc); size = size * conf->raid_disks; sector_div(size, nc); /* 'size' is now the number of chunks in the array */ /* calculate "used chunks per device" in 'stride' */ stride = size * conf->copies; /* We need to round up when dividing by raid_disks to * get the stride size. */ stride += conf->raid_disks - 1; sector_div(stride, conf->raid_disks); mddev->size = stride << (conf->chunk_shift-1); if (fo) stride = 1; else sector_div(stride, fc); conf->stride = stride << conf->chunk_shift; conf->r10bio_pool = mempool_create(NR_RAID10_BIOS, r10bio_pool_alloc, r10bio_pool_free, conf); if (!conf->r10bio_pool) { printk(KERN_ERR "raid10: couldn't allocate memory for %s\n", mdname(mddev)); goto out_free_conf; } spin_lock_init(&conf->device_lock); mddev->queue->queue_lock = &conf->device_lock; rdev_for_each(rdev, tmp, mddev) { disk_idx = rdev->raid_disk; if (disk_idx >= mddev->raid_disks || disk_idx < 0) continue; disk = conf->mirrors + disk_idx; disk->rdev = rdev; blk_queue_stack_limits(mddev->queue, rdev->bdev->bd_disk->queue); /* as we don't honour merge_bvec_fn, we must never risk * violating it, so limit ->max_sector to one PAGE, as * a one page request is never in violation. */ if (rdev->bdev->bd_disk->queue->merge_bvec_fn && mddev->queue->max_sectors > (PAGE_SIZE>>9)) mddev->queue->max_sectors = (PAGE_SIZE>>9); disk->head_position = 0; } INIT_LIST_HEAD(&conf->retry_list); spin_lock_init(&conf->resync_lock); init_waitqueue_head(&conf->wait_barrier); /* need to check that every block has at least one working mirror */ if (!enough(conf)) { printk(KERN_ERR "raid10: not enough 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 || !test_bit(In_sync, &disk->rdev->flags)) { disk->head_position = 0; mddev->degraded++; if (disk->rdev) conf->fullsync = 1; } } mddev->thread = md_register_thread(raid10d, mddev, "%s_raid10"); if (!mddev->thread) { printk(KERN_ERR "raid10: couldn't allocate thread for %s\n", mdname(mddev)); goto out_free_conf; } printk(KERN_INFO "raid10: raid set %s active with %d out of %d devices\n", mdname(mddev), mddev->raid_disks - mddev->degraded, mddev->raid_disks); /* * Ok, everything is just fine now */ mddev->array_sectors = size << conf->chunk_shift; mddev->resync_max_sectors = size << conf->chunk_shift; mddev->queue->unplug_fn = raid10_unplug; mddev->queue->backing_dev_info.congested_fn = raid10_congested; mddev->queue->backing_dev_info.congested_data = mddev; /* Calculate max read-ahead size. * We need to readahead at least twice a whole stripe.... * maybe... */ { int stripe = conf->raid_disks * (mddev->chunk_size / PAGE_SIZE); stripe /= conf->near_copies; if (mddev->queue->backing_dev_info.ra_pages < 2* stripe) mddev->queue->backing_dev_info.ra_pages = 2* stripe; } if (conf->near_copies < mddev->raid_disks) blk_queue_merge_bvec(mddev->queue, raid10_mergeable_bvec); return 0; out_free_conf: if (conf->r10bio_pool) mempool_destroy(conf->r10bio_pool); safe_put_page(conf->tmppage); kfree(conf->mirrors); kfree(conf); mddev->private = NULL; out: return -EIO; } static int stop(mddev_t *mddev) { conf_t *conf = mddev_to_conf(mddev); md_unregister_thread(mddev->thread); mddev->thread = NULL; blk_sync_queue(mddev->queue); /* the unplug fn references 'conf'*/ if (conf->r10bio_pool) mempool_destroy(conf->r10bio_pool); kfree(conf->mirrors); kfree(conf); mddev->private = NULL; return 0; } static void raid10_quiesce(mddev_t *mddev, int state) { conf_t *conf = mddev_to_conf(mddev); switch(state) { case 1: raise_barrier(conf, 0); break; case 0: lower_barrier(conf); break; } if (mddev->thread) { if (mddev->bitmap) mddev->thread->timeout = mddev->bitmap->daemon_sleep * HZ; else mddev->thread->timeout = MAX_SCHEDULE_TIMEOUT; md_wakeup_thread(mddev->thread); } } static struct mdk_personality raid10_personality = { .name = "raid10", .level = 10, .owner = THIS_MODULE, .make_request = make_request, .run = run, .stop = stop, .status = status, .error_handler = error, .hot_add_disk = raid10_add_disk, .hot_remove_disk= raid10_remove_disk, .spare_active = raid10_spare_active, .sync_request = sync_request, .quiesce = raid10_quiesce, }; static int __init raid_init(void) { return register_md_personality(&raid10_personality); } static void raid_exit(void) { unregister_md_personality(&raid10_personality); } module_init(raid_init); module_exit(raid_exit); MODULE_LICENSE("GPL"); MODULE_ALIAS("md-personality-9"); /* RAID10 */ MODULE_ALIAS("md-raid10"); MODULE_ALIAS("md-level-10");