/* * 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 further 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 #include #include #include #include #include #include "md.h" #include "raid10.h" #include "raid0.h" #include "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 /* When there are this many requests queue to be written by * the raid10 thread, we become 'congested' to provide back-pressure * for writeback. */ static int max_queued_requests = 1024; static void allow_barrier(struct r10conf *conf); static void lower_barrier(struct r10conf *conf); static void * r10bio_pool_alloc(gfp_t gfp_flags, void *data) { struct r10conf *conf = data; int size = offsetof(struct r10bio, devs[conf->copies]); /* allocate a r10bio with room for raid_disks entries in the * bios array */ return kzalloc(size, gfp_flags); } 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) { struct r10conf *conf = data; struct page *page; struct r10bio *r10_bio; struct bio *bio; int i, j; int nalloc; r10_bio = r10bio_pool_alloc(gfp_flags, conf); if (!r10_bio) 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_kmalloc(gfp_flags, RESYNC_PAGES); if (!bio) goto out_free_bio; r10_bio->devs[j].bio = bio; if (!conf->have_replacement) continue; bio = bio_kmalloc(gfp_flags, RESYNC_PAGES); if (!bio) goto out_free_bio; r10_bio->devs[j].repl_bio = bio; } /* * Allocate RESYNC_PAGES data pages and attach them * where needed. */ for (j = 0 ; j < nalloc; j++) { struct bio *rbio = r10_bio->devs[j].repl_bio; bio = r10_bio->devs[j].bio; for (i = 0; i < RESYNC_PAGES; i++) { if (j == 1 && !test_bit(MD_RECOVERY_SYNC, &conf->mddev->recovery)) { /* we can share bv_page's during recovery */ struct bio *rbio = r10_bio->devs[0].bio; page = rbio->bi_io_vec[i].bv_page; get_page(page); } else page = alloc_page(gfp_flags); if (unlikely(!page)) goto out_free_pages; bio->bi_io_vec[i].bv_page = page; if (rbio) rbio->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); if (r10_bio->devs[j].repl_bio) bio_put(r10_bio->devs[j].repl_bio); } r10bio_pool_free(r10_bio, conf); return NULL; } static void r10buf_pool_free(void *__r10_bio, void *data) { int i; struct r10conf *conf = data; struct r10bio *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); } bio = r10bio->devs[j].repl_bio; if (bio) bio_put(bio); } r10bio_pool_free(r10bio, conf); } static void put_all_bios(struct r10conf *conf, struct r10bio *r10_bio) { int i; for (i = 0; i < conf->copies; i++) { struct bio **bio = & r10_bio->devs[i].bio; if (!BIO_SPECIAL(*bio)) bio_put(*bio); *bio = NULL; bio = &r10_bio->devs[i].repl_bio; if (r10_bio->read_slot < 0 && !BIO_SPECIAL(*bio)) bio_put(*bio); *bio = NULL; } } static void free_r10bio(struct r10bio *r10_bio) { struct r10conf *conf = r10_bio->mddev->private; put_all_bios(conf, r10_bio); mempool_free(r10_bio, conf->r10bio_pool); } static void put_buf(struct r10bio *r10_bio) { struct r10conf *conf = r10_bio->mddev->private; mempool_free(r10_bio, conf->r10buf_pool); lower_barrier(conf); } static void reschedule_retry(struct r10bio *r10_bio) { unsigned long flags; struct mddev *mddev = r10_bio->mddev; struct r10conf *conf = mddev->private; 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(struct r10bio *r10_bio) { struct bio *bio = r10_bio->master_bio; int done; struct r10conf *conf = r10_bio->mddev->private; if (bio->bi_phys_segments) { unsigned long flags; spin_lock_irqsave(&conf->device_lock, flags); bio->bi_phys_segments--; done = (bio->bi_phys_segments == 0); spin_unlock_irqrestore(&conf->device_lock, flags); } else done = 1; if (!test_bit(R10BIO_Uptodate, &r10_bio->state)) clear_bit(BIO_UPTODATE, &bio->bi_flags); if (done) { bio_endio(bio, 0); /* * Wake up any possible resync thread that waits for the device * to go idle. */ allow_barrier(conf); } free_r10bio(r10_bio); } /* * Update disk head position estimator based on IRQ completion info. */ static inline void update_head_pos(int slot, struct r10bio *r10_bio) { struct r10conf *conf = r10_bio->mddev->private; conf->mirrors[r10_bio->devs[slot].devnum].head_position = r10_bio->devs[slot].addr + (r10_bio->sectors); } /* * Find the disk number which triggered given bio */ static int find_bio_disk(struct r10conf *conf, struct r10bio *r10_bio, struct bio *bio, int *slotp, int *replp) { int slot; int repl = 0; for (slot = 0; slot < conf->copies; slot++) { if (r10_bio->devs[slot].bio == bio) break; if (r10_bio->devs[slot].repl_bio == bio) { repl = 1; break; } } BUG_ON(slot == conf->copies); update_head_pos(slot, r10_bio); if (slotp) *slotp = slot; if (replp) *replp = repl; return r10_bio->devs[slot].devnum; } static void raid10_end_read_request(struct bio *bio, int error) { int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags); struct r10bio *r10_bio = bio->bi_private; int slot, dev; struct md_rdev *rdev; struct r10conf *conf = r10_bio->mddev->private; slot = r10_bio->read_slot; dev = r10_bio->devs[slot].devnum; rdev = r10_bio->devs[slot].rdev; /* * 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); rdev_dec_pending(rdev, conf->mddev); } else { /* * oops, read error - keep the refcount on the rdev */ char b[BDEVNAME_SIZE]; printk_ratelimited(KERN_ERR "md/raid10:%s: %s: rescheduling sector %llu\n", mdname(conf->mddev), bdevname(rdev->bdev, b), (unsigned long long)r10_bio->sector); set_bit(R10BIO_ReadError, &r10_bio->state); reschedule_retry(r10_bio); } } static void close_write(struct r10bio *r10_bio) { /* 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); } static void one_write_done(struct r10bio *r10_bio) { if (atomic_dec_and_test(&r10_bio->remaining)) { if (test_bit(R10BIO_WriteError, &r10_bio->state)) reschedule_retry(r10_bio); else { close_write(r10_bio); if (test_bit(R10BIO_MadeGood, &r10_bio->state)) reschedule_retry(r10_bio); else raid_end_bio_io(r10_bio); } } } static void raid10_end_write_request(struct bio *bio, int error) { int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags); struct r10bio *r10_bio = bio->bi_private; int dev; int dec_rdev = 1; struct r10conf *conf = r10_bio->mddev->private; int slot, repl; struct md_rdev *rdev = NULL; dev = find_bio_disk(conf, r10_bio, bio, &slot, &repl); if (repl) rdev = conf->mirrors[dev].replacement; if (!rdev) { smp_rmb(); repl = 0; rdev = conf->mirrors[dev].rdev; } /* * this branch is our 'one mirror IO has finished' event handler: */ if (!uptodate) { if (repl) /* Never record new bad blocks to replacement, * just fail it. */ md_error(rdev->mddev, rdev); else { set_bit(WriteErrorSeen, &rdev->flags); if (!test_and_set_bit(WantReplacement, &rdev->flags)) set_bit(MD_RECOVERY_NEEDED, &rdev->mddev->recovery); set_bit(R10BIO_WriteError, &r10_bio->state); dec_rdev = 0; } } 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. */ sector_t first_bad; int bad_sectors; set_bit(R10BIO_Uptodate, &r10_bio->state); /* Maybe we can clear some bad blocks. */ if (is_badblock(rdev, r10_bio->devs[slot].addr, r10_bio->sectors, &first_bad, &bad_sectors)) { bio_put(bio); if (repl) r10_bio->devs[slot].repl_bio = IO_MADE_GOOD; else r10_bio->devs[slot].bio = IO_MADE_GOOD; dec_rdev = 0; set_bit(R10BIO_MadeGood, &r10_bio->state); } } /* * * Let's see if all mirrored write operations have finished * already. */ one_write_done(r10_bio); if (dec_rdev) rdev_dec_pending(conf->mirrors[dev].rdev, conf->mddev); } /* * RAID10 layout manager * As well 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 laid 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(struct r10conf *conf, struct r10bio *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(struct r10conf *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) { struct mddev *mddev = q->queuedata; sector_t sector = bvm->bi_sector + get_start_sect(bvm->bi_bdev); int max; unsigned int chunk_sectors = mddev->chunk_sectors; 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 struct md_rdev *read_balance(struct r10conf *conf, struct r10bio *r10_bio, int *max_sectors) { const sector_t this_sector = r10_bio->sector; int disk, slot; int sectors = r10_bio->sectors; int best_good_sectors; sector_t new_distance, best_dist; struct md_rdev *rdev, *best_rdev; int do_balance; int best_slot; raid10_find_phys(conf, r10_bio); rcu_read_lock(); retry: sectors = r10_bio->sectors; best_slot = -1; best_rdev = NULL; best_dist = MaxSector; best_good_sectors = 0; do_balance = 1; /* * 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)) do_balance = 0; for (slot = 0; slot < conf->copies ; slot++) { sector_t first_bad; int bad_sectors; sector_t dev_sector; if (r10_bio->devs[slot].bio == IO_BLOCKED) continue; disk = r10_bio->devs[slot].devnum; rdev = rcu_dereference(conf->mirrors[disk].replacement); if (rdev == NULL || test_bit(Faulty, &rdev->flags) || r10_bio->devs[slot].addr + sectors > rdev->recovery_offset) rdev = rcu_dereference(conf->mirrors[disk].rdev); if (rdev == NULL) continue; if (test_bit(Faulty, &rdev->flags)) continue; if (!test_bit(In_sync, &rdev->flags) && r10_bio->devs[slot].addr + sectors > rdev->recovery_offset) continue; dev_sector = r10_bio->devs[slot].addr; if (is_badblock(rdev, dev_sector, sectors, &first_bad, &bad_sectors)) { if (best_dist < MaxSector) /* Already have a better slot */ continue; if (first_bad <= dev_sector) { /* Cannot read here. If this is the * 'primary' device, then we must not read * beyond 'bad_sectors' from another device. */ bad_sectors -= (dev_sector - first_bad); if (!do_balance && sectors > bad_sectors) sectors = bad_sectors; if (best_good_sectors > sectors) best_good_sectors = sectors; } else { sector_t good_sectors = first_bad - dev_sector; if (good_sectors > best_good_sectors) { best_good_sectors = good_sectors; best_slot = slot; best_rdev = rdev; } if (!do_balance) /* Must read from here */ break; } continue; } else best_good_sectors = sectors; if (!do_balance) break; /* 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)) break; /* for far > 1 always use the lowest address */ if (conf->far_copies > 1) new_distance = r10_bio->devs[slot].addr; else new_distance = abs(r10_bio->devs[slot].addr - conf->mirrors[disk].head_position); if (new_distance < best_dist) { best_dist = new_distance; best_slot = slot; best_rdev = rdev; } } if (slot >= conf->copies) { slot = best_slot; rdev = best_rdev; } if (slot >= 0) { 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; } r10_bio->read_slot = slot; } else rdev = NULL; rcu_read_unlock(); *max_sectors = best_good_sectors; return rdev; } static int raid10_congested(void *data, int bits) { struct mddev *mddev = data; struct r10conf *conf = mddev->private; int i, ret = 0; if ((bits & (1 << BDI_async_congested)) && conf->pending_count >= max_queued_requests) return 1; if (mddev_congested(mddev, bits)) return 1; rcu_read_lock(); for (i = 0; i < conf->raid_disks && ret == 0; i++) { struct md_rdev *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 void flush_pending_writes(struct r10conf *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); conf->pending_count = 0; spin_unlock_irq(&conf->device_lock); /* flush any pending bitmap writes to disk * before proceeding w/ I/O */ bitmap_unplug(conf->mddev->bitmap); wake_up(&conf->wait_barrier); 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. */ static void raise_barrier(struct r10conf *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, ); /* 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(struct r10conf *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(struct r10conf *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, ); conf->nr_waiting--; } conf->nr_pending++; spin_unlock_irq(&conf->resync_lock); } static void allow_barrier(struct r10conf *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(struct r10conf *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)); spin_unlock_irq(&conf->resync_lock); } static void unfreeze_array(struct r10conf *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 void make_request(struct mddev *mddev, struct bio * bio) { struct r10conf *conf = mddev->private; struct r10bio *r10_bio; struct bio *read_bio; int i; int chunk_sects = conf->chunk_mask + 1; const int rw = bio_data_dir(bio); const unsigned long do_sync = (bio->bi_rw & REQ_SYNC); const unsigned long do_fua = (bio->bi_rw & REQ_FUA); unsigned long flags; struct md_rdev *blocked_rdev; int plugged; int sectors_handled; int max_sectors; if (unlikely(bio->bi_rw & REQ_FLUSH)) { md_flush_request(mddev, bio); return; } /* 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)) ); /* Each of these 'make_request' calls will call 'wait_barrier'. * If the first succeeds but the second blocks due to the resync * thread raising the barrier, we will deadlock because the * IO to the underlying device will be queued in generic_make_request * and will never complete, so will never reduce nr_pending. * So increment nr_waiting here so no new raise_barriers will * succeed, and so the second wait_barrier cannot block. */ spin_lock_irq(&conf->resync_lock); conf->nr_waiting++; spin_unlock_irq(&conf->resync_lock); make_request(mddev, &bp->bio1); make_request(mddev, &bp->bio2); spin_lock_irq(&conf->resync_lock); conf->nr_waiting--; wake_up(&conf->wait_barrier); spin_unlock_irq(&conf->resync_lock); bio_pair_release(bp); return; bad_map: printk("md/raid10:%s: make_request bug: can't convert block across chunks" " or bigger than %dk %llu %d\n", mdname(mddev), chunk_sects/2, (unsigned long long)bio->bi_sector, bio->bi_size >> 10); bio_io_error(bio); return; } 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); 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; /* We might need to issue multiple reads to different * devices if there are bad blocks around, so we keep * track of the number of reads in bio->bi_phys_segments. * If this is 0, there is only one r10_bio and no locking * will be needed when the request completes. If it is * non-zero, then it is the number of not-completed requests. */ bio->bi_phys_segments = 0; clear_bit(BIO_SEG_VALID, &bio->bi_flags); if (rw == READ) { /* * read balancing logic: */ struct md_rdev *rdev; int slot; read_again: rdev = read_balance(conf, r10_bio, &max_sectors); if (!rdev) { raid_end_bio_io(r10_bio); return; } slot = r10_bio->read_slot; read_bio = bio_clone_mddev(bio, GFP_NOIO, mddev); md_trim_bio(read_bio, r10_bio->sector - bio->bi_sector, max_sectors); r10_bio->devs[slot].bio = read_bio; r10_bio->devs[slot].rdev = rdev; read_bio->bi_sector = r10_bio->devs[slot].addr + rdev->data_offset; read_bio->bi_bdev = rdev->bdev; read_bio->bi_end_io = raid10_end_read_request; read_bio->bi_rw = READ | do_sync; read_bio->bi_private = r10_bio; if (max_sectors < r10_bio->sectors) { /* Could not read all from this device, so we will * need another r10_bio. */ sectors_handled = (r10_bio->sectors + max_sectors - bio->bi_sector); r10_bio->sectors = max_sectors; spin_lock_irq(&conf->device_lock); if (bio->bi_phys_segments == 0) bio->bi_phys_segments = 2; else bio->bi_phys_segments++; spin_unlock(&conf->device_lock); /* Cannot call generic_make_request directly * as that will be queued in __generic_make_request * and subsequent mempool_alloc might block * waiting for it. so hand bio over to raid10d. */ reschedule_retry(r10_bio); r10_bio = mempool_alloc(conf->r10bio_pool, GFP_NOIO); r10_bio->master_bio = bio; r10_bio->sectors = ((bio->bi_size >> 9) - sectors_handled); r10_bio->state = 0; r10_bio->mddev = mddev; r10_bio->sector = bio->bi_sector + sectors_handled; goto read_again; } else generic_make_request(read_bio); return; } /* * WRITE: */ if (conf->pending_count >= max_queued_requests) { md_wakeup_thread(mddev->thread); wait_event(conf->wait_barrier, conf->pending_count < max_queued_requests); } /* first select target devices under rcu_lock and * inc refcount on their rdev. Record them by setting * bios[x] to bio * If there are known/acknowledged bad blocks on any device * on which we have seen a write error, we want to avoid * writing to those blocks. This potentially requires several * writes to write around the bad blocks. Each set of writes * gets its own r10_bio with a set of bios attached. The number * of r10_bios is recored in bio->bi_phys_segments just as with * the read case. */ plugged = mddev_check_plugged(mddev); r10_bio->read_slot = -1; /* make sure repl_bio gets freed */ raid10_find_phys(conf, r10_bio); retry_write: blocked_rdev = NULL; rcu_read_lock(); max_sectors = r10_bio->sectors; for (i = 0; i < conf->copies; i++) { int d = r10_bio->devs[i].devnum; struct md_rdev *rdev = rcu_dereference(conf->mirrors[d].rdev); struct md_rdev *rrdev = rcu_dereference( conf->mirrors[d].replacement); if (rdev == rrdev) rrdev = NULL; if (rdev && unlikely(test_bit(Blocked, &rdev->flags))) { atomic_inc(&rdev->nr_pending); blocked_rdev = rdev; break; } if (rrdev && unlikely(test_bit(Blocked, &rrdev->flags))) { atomic_inc(&rrdev->nr_pending); blocked_rdev = rrdev; break; } if (rrdev && test_bit(Faulty, &rrdev->flags)) rrdev = NULL; r10_bio->devs[i].bio = NULL; r10_bio->devs[i].repl_bio = NULL; if (!rdev || test_bit(Faulty, &rdev->flags)) { set_bit(R10BIO_Degraded, &r10_bio->state); continue; } if (test_bit(WriteErrorSeen, &rdev->flags)) { sector_t first_bad; sector_t dev_sector = r10_bio->devs[i].addr; int bad_sectors; int is_bad; is_bad = is_badblock(rdev, dev_sector, max_sectors, &first_bad, &bad_sectors); if (is_bad < 0) { /* Mustn't write here until the bad block * is acknowledged */ atomic_inc(&rdev->nr_pending); set_bit(BlockedBadBlocks, &rdev->flags); blocked_rdev = rdev; break; } if (is_bad && first_bad <= dev_sector) { /* Cannot write here at all */ bad_sectors -= (dev_sector - first_bad); if (bad_sectors < max_sectors) /* Mustn't write more than bad_sectors * to other devices yet */ max_sectors = bad_sectors; /* We don't set R10BIO_Degraded as that * only applies if the disk is missing, * so it might be re-added, and we want to * know to recover this chunk. * In this case the device is here, and the * fact that this chunk is not in-sync is * recorded in the bad block log. */ continue; } if (is_bad) { int good_sectors = first_bad - dev_sector; if (good_sectors < max_sectors) max_sectors = good_sectors; } } r10_bio->devs[i].bio = bio; atomic_inc(&rdev->nr_pending); if (rrdev) { r10_bio->devs[i].repl_bio = bio; atomic_inc(&rrdev->nr_pending); } } 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); } if (r10_bio->devs[j].repl_bio) { struct md_rdev *rdev; d = r10_bio->devs[j].devnum; rdev = conf->mirrors[d].replacement; if (!rdev) { /* Race with remove_disk */ smp_mb(); rdev = conf->mirrors[d].rdev; } rdev_dec_pending(rdev, mddev); } } allow_barrier(conf); md_wait_for_blocked_rdev(blocked_rdev, mddev); wait_barrier(conf); goto retry_write; } if (max_sectors < r10_bio->sectors) { /* We are splitting this into multiple parts, so * we need to prepare for allocating another r10_bio. */ r10_bio->sectors = max_sectors; spin_lock_irq(&conf->device_lock); if (bio->bi_phys_segments == 0) bio->bi_phys_segments = 2; else bio->bi_phys_segments++; spin_unlock_irq(&conf->device_lock); } sectors_handled = r10_bio->sector + max_sectors - bio->bi_sector; atomic_set(&r10_bio->remaining, 1); bitmap_startwrite(mddev->bitmap, r10_bio->sector, r10_bio->sectors, 0); 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_mddev(bio, GFP_NOIO, mddev); md_trim_bio(mbio, r10_bio->sector - bio->bi_sector, max_sectors); 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 | do_fua; mbio->bi_private = r10_bio; atomic_inc(&r10_bio->remaining); spin_lock_irqsave(&conf->device_lock, flags); bio_list_add(&conf->pending_bio_list, mbio); conf->pending_count++; spin_unlock_irqrestore(&conf->device_lock, flags); if (!r10_bio->devs[i].repl_bio) continue; mbio = bio_clone_mddev(bio, GFP_NOIO, mddev); md_trim_bio(mbio, r10_bio->sector - bio->bi_sector, max_sectors); r10_bio->devs[i].repl_bio = mbio; /* We are actively writing to the original device * so it cannot disappear, so the replacement cannot * become NULL here */ mbio->bi_sector = (r10_bio->devs[i].addr+ conf->mirrors[d].replacement->data_offset); mbio->bi_bdev = conf->mirrors[d].replacement->bdev; mbio->bi_end_io = raid10_end_write_request; mbio->bi_rw = WRITE | do_sync | do_fua; mbio->bi_private = r10_bio; atomic_inc(&r10_bio->remaining); spin_lock_irqsave(&conf->device_lock, flags); bio_list_add(&conf->pending_bio_list, mbio); conf->pending_count++; spin_unlock_irqrestore(&conf->device_lock, flags); } /* Don't remove the bias on 'remaining' (one_write_done) until * after checking if we need to go around again. */ if (sectors_handled < (bio->bi_size >> 9)) { one_write_done(r10_bio); /* We need another r10_bio. It has already been counted * in bio->bi_phys_segments. */ r10_bio = mempool_alloc(conf->r10bio_pool, GFP_NOIO); r10_bio->master_bio = bio; r10_bio->sectors = (bio->bi_size >> 9) - sectors_handled; r10_bio->mddev = mddev; r10_bio->sector = bio->bi_sector + sectors_handled; r10_bio->state = 0; goto retry_write; } one_write_done(r10_bio); /* In case raid10d snuck in to freeze_array */ wake_up(&conf->wait_barrier); if (do_sync || !mddev->bitmap || !plugged) md_wakeup_thread(mddev->thread); } static void status(struct seq_file *seq, struct mddev *mddev) { struct r10conf *conf = mddev->private; int i; if (conf->near_copies < conf->raid_disks) seq_printf(seq, " %dK chunks", mddev->chunk_sectors / 2); 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, "]"); } /* check if there are enough drives for * every block to appear on atleast one. * Don't consider the device numbered 'ignore' * as we might be about to remove it. */ static int enough(struct r10conf *conf, int ignore) { int first = 0; do { int n = conf->copies; int cnt = 0; while (n--) { if (conf->mirrors[first].rdev && first != ignore) cnt++; first = (first+1) % conf->raid_disks; } if (cnt == 0) return 0; } while (first != 0); return 1; } static void error(struct mddev *mddev, struct md_rdev *rdev) { char b[BDEVNAME_SIZE]; struct r10conf *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) && !enough(conf, rdev->raid_disk)) /* * Don't fail the drive, just return an IO error. */ 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(Blocked, &rdev->flags); set_bit(Faulty, &rdev->flags); set_bit(MD_CHANGE_DEVS, &mddev->flags); printk(KERN_ALERT "md/raid10:%s: Disk failure on %s, disabling device.\n" "md/raid10:%s: Operation continuing on %d devices.\n", mdname(mddev), bdevname(rdev->bdev, b), mdname(mddev), conf->raid_disks - mddev->degraded); } static void print_conf(struct r10conf *conf) { int i; struct mirror_info *tmp; printk(KERN_DEBUG "RAID10 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); for (i = 0; i < conf->raid_disks; i++) { char b[BDEVNAME_SIZE]; tmp = conf->mirrors + i; if (tmp->rdev) printk(KERN_DEBUG " 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(struct r10conf *conf) { wait_barrier(conf); allow_barrier(conf); mempool_destroy(conf->r10buf_pool); conf->r10buf_pool = NULL; } static int raid10_spare_active(struct mddev *mddev) { int i; struct r10conf *conf = mddev->private; struct mirror_info *tmp; int count = 0; unsigned long flags; /* * 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->replacement && tmp->replacement->recovery_offset == MaxSector && !test_bit(Faulty, &tmp->replacement->flags) && !test_and_set_bit(In_sync, &tmp->replacement->flags)) { /* Replacement has just become active */ if (!tmp->rdev || !test_and_clear_bit(In_sync, &tmp->rdev->flags)) count++; if (tmp->rdev) { /* Replaced device not technically faulty, * but we need to be sure it gets removed * and never re-added. */ set_bit(Faulty, &tmp->rdev->flags); sysfs_notify_dirent_safe( tmp->rdev->sysfs_state); } sysfs_notify_dirent_safe(tmp->replacement->sysfs_state); } else if (tmp->rdev && !test_bit(Faulty, &tmp->rdev->flags) && !test_and_set_bit(In_sync, &tmp->rdev->flags)) { count++; sysfs_notify_dirent(tmp->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 raid10_add_disk(struct mddev *mddev, struct md_rdev *rdev) { struct r10conf *conf = mddev->private; int err = -EEXIST; int mirror; int first = 0; int last = conf->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, -1)) return -EINVAL; if (rdev->raid_disk >= 0) first = last = rdev->raid_disk; if (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++) { struct mirror_info *p = &conf->mirrors[mirror]; if (p->recovery_disabled == mddev->recovery_disabled) continue; if (p->rdev) { if (!test_bit(WantReplacement, &p->rdev->flags) || p->replacement != NULL) continue; clear_bit(In_sync, &rdev->flags); set_bit(Replacement, &rdev->flags); rdev->raid_disk = mirror; err = 0; disk_stack_limits(mddev->gendisk, rdev->bdev, rdev->data_offset << 9); 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); } conf->fullsync = 1; rcu_assign_pointer(p->replacement, rdev); break; } 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; p->recovery_disabled = mddev->recovery_disabled - 1; rdev->raid_disk = mirror; err = 0; if (rdev->saved_raid_disk != mirror) conf->fullsync = 1; rcu_assign_pointer(p->rdev, rdev); break; } md_integrity_add_rdev(rdev, mddev); print_conf(conf); return err; } static int raid10_remove_disk(struct mddev *mddev, struct md_rdev *rdev) { struct r10conf *conf = mddev->private; int err = 0; int number = rdev->raid_disk; struct md_rdev **rdevp; struct mirror_info *p = conf->mirrors + number; print_conf(conf); if (rdev == p->rdev) rdevp = &p->rdev; else if (rdev == p->replacement) rdevp = &p->replacement; else return 0; if (test_bit(In_sync, &rdev->flags) || atomic_read(&rdev->nr_pending)) { err = -EBUSY; goto abort; } /* Only remove faulty devices if recovery * is not possible. */ if (!test_bit(Faulty, &rdev->flags) && mddev->recovery_disabled != p->recovery_disabled && (!p->replacement || p->replacement == rdev) && enough(conf, -1)) { err = -EBUSY; goto abort; } *rdevp = NULL; synchronize_rcu(); if (atomic_read(&rdev->nr_pending)) { /* lost the race, try later */ err = -EBUSY; *rdevp = rdev; goto abort; } else if (p->replacement) { /* We must have just cleared 'rdev' */ p->rdev = p->replacement; clear_bit(Replacement, &p->replacement->flags); smp_mb(); /* Make sure other CPUs may see both as identical * but will never see neither -- if they are careful. */ p->replacement = NULL; clear_bit(WantReplacement, &rdev->flags); } else /* We might have just remove the Replacement as faulty * Clear the flag just in case */ clear_bit(WantReplacement, &rdev->flags); err = md_integrity_register(mddev); abort: print_conf(conf); return err; } static void end_sync_read(struct bio *bio, int error) { struct r10bio *r10_bio = bio->bi_private; struct r10conf *conf = r10_bio->mddev->private; int d; d = find_bio_disk(conf, r10_bio, bio, NULL, NULL); if (test_bit(BIO_UPTODATE, &bio->bi_flags)) set_bit(R10BIO_Uptodate, &r10_bio->state); else /* The write handler will notice the lack of * R10BIO_Uptodate and record any errors etc */ atomic_add(r10_bio->sectors, &conf->mirrors[d].rdev->corrected_errors); /* for reconstruct, we always reschedule after a read. * for resync, only after all reads */ rdev_dec_pending(conf->mirrors[d].rdev, conf->mddev); 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); } } static void end_sync_request(struct r10bio *r10_bio) { struct mddev *mddev = r10_bio->mddev; while (atomic_dec_and_test(&r10_bio->remaining)) { if (r10_bio->master_bio == NULL) { /* the primary of several recovery bios */ sector_t s = r10_bio->sectors; if (test_bit(R10BIO_MadeGood, &r10_bio->state) || test_bit(R10BIO_WriteError, &r10_bio->state)) reschedule_retry(r10_bio); else put_buf(r10_bio); md_done_sync(mddev, s, 1); break; } else { struct r10bio *r10_bio2 = (struct r10bio *)r10_bio->master_bio; if (test_bit(R10BIO_MadeGood, &r10_bio->state) || test_bit(R10BIO_WriteError, &r10_bio->state)) reschedule_retry(r10_bio); else put_buf(r10_bio); r10_bio = r10_bio2; } } } static void end_sync_write(struct bio *bio, int error) { int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags); struct r10bio *r10_bio = bio->bi_private; struct mddev *mddev = r10_bio->mddev; struct r10conf *conf = mddev->private; int d; sector_t first_bad; int bad_sectors; int slot; int repl; struct md_rdev *rdev = NULL; d = find_bio_disk(conf, r10_bio, bio, &slot, &repl); if (repl) rdev = conf->mirrors[d].replacement; if (!rdev) { smp_mb(); rdev = conf->mirrors[d].rdev; } if (!uptodate) { if (repl) md_error(mddev, rdev); else { set_bit(WriteErrorSeen, &rdev->flags); if (!test_and_set_bit(WantReplacement, &rdev->flags)) set_bit(MD_RECOVERY_NEEDED, &rdev->mddev->recovery); set_bit(R10BIO_WriteError, &r10_bio->state); } } else if (is_badblock(rdev, r10_bio->devs[slot].addr, r10_bio->sectors, &first_bad, &bad_sectors)) set_bit(R10BIO_MadeGood, &r10_bio->state); rdev_dec_pending(rdev, mddev); end_sync_request(r10_bio); } /* * 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(struct mddev *mddev, struct r10bio *r10_bio) { struct r10conf *conf = mddev->private; int i, first; struct bio *tbio, *fbio; atomic_set(&r10_bio->remaining, 1); /* find the first device with a block */ for (i=0; icopies; 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, either to correct an * inconsistency or to correct an unreadable block. * 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); } /* Now write out to any replacement devices * that are active */ for (i = 0; i < conf->copies; i++) { int j, d; int vcnt = r10_bio->sectors >> (PAGE_SHIFT-9); tbio = r10_bio->devs[i].repl_bio; if (!tbio || !tbio->bi_end_io) continue; if (r10_bio->devs[i].bio->bi_end_io != end_sync_write && r10_bio->devs[i].bio != fbio) for (j = 0; j < vcnt; j++) memcpy(page_address(tbio->bi_io_vec[j].bv_page), page_address(fbio->bi_io_vec[j].bv_page), PAGE_SIZE); d = r10_bio->devs[i].devnum; atomic_inc(&r10_bio->remaining); md_sync_acct(conf->mirrors[d].replacement->bdev, tbio->bi_size >> 9); 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 fix_recovery_read_error(struct r10bio *r10_bio) { /* We got a read error during recovery. * We repeat the read in smaller page-sized sections. * If a read succeeds, write it to the new device or record * a bad block if we cannot. * If a read fails, record a bad block on both old and * new devices. */ struct mddev *mddev = r10_bio->mddev; struct r10conf *conf = mddev->private; struct bio *bio = r10_bio->devs[0].bio; sector_t sect = 0; int sectors = r10_bio->sectors; int idx = 0; int dr = r10_bio->devs[0].devnum; int dw = r10_bio->devs[1].devnum; while (sectors) { int s = sectors; struct md_rdev *rdev; sector_t addr; int ok; if (s > (PAGE_SIZE>>9)) s = PAGE_SIZE >> 9; rdev = conf->mirrors[dr].rdev; addr = r10_bio->devs[0].addr + sect, ok = sync_page_io(rdev, addr, s << 9, bio->bi_io_vec[idx].bv_page, READ, false); if (ok) { rdev = conf->mirrors[dw].rdev; addr = r10_bio->devs[1].addr + sect; ok = sync_page_io(rdev, addr, s << 9, bio->bi_io_vec[idx].bv_page, WRITE, false); if (!ok) { set_bit(WriteErrorSeen, &rdev->flags); if (!test_and_set_bit(WantReplacement, &rdev->flags)) set_bit(MD_RECOVERY_NEEDED, &rdev->mddev->recovery); } } if (!ok) { /* We don't worry if we cannot set a bad block - * it really is bad so there is no loss in not * recording it yet */ rdev_set_badblocks(rdev, addr, s, 0); if (rdev != conf->mirrors[dw].rdev) { /* need bad block on destination too */ struct md_rdev *rdev2 = conf->mirrors[dw].rdev; addr = r10_bio->devs[1].addr + sect; ok = rdev_set_badblocks(rdev2, addr, s, 0); if (!ok) { /* just abort the recovery */ printk(KERN_NOTICE "md/raid10:%s: recovery aborted" " due to read error\n", mdname(mddev)); conf->mirrors[dw].recovery_disabled = mddev->recovery_disabled; set_bit(MD_RECOVERY_INTR, &mddev->recovery); break; } } } sectors -= s; sect += s; idx++; } } static void recovery_request_write(struct mddev *mddev, struct r10bio *r10_bio) { struct r10conf *conf = mddev->private; int d; struct bio *wbio, *wbio2; if (!test_bit(R10BIO_Uptodate, &r10_bio->state)) { fix_recovery_read_error(r10_bio); end_sync_request(r10_bio); return; } /* * share the pages with the first bio * and submit the write request */ d = r10_bio->devs[1].devnum; wbio = r10_bio->devs[1].bio; wbio2 = r10_bio->devs[1].repl_bio; if (wbio->bi_end_io) { atomic_inc(&conf->mirrors[d].rdev->nr_pending); md_sync_acct(conf->mirrors[d].rdev->bdev, wbio->bi_size >> 9); generic_make_request(wbio); } if (wbio2 && wbio2->bi_end_io) { atomic_inc(&conf->mirrors[d].replacement->nr_pending); md_sync_acct(conf->mirrors[d].replacement->bdev, wbio2->bi_size >> 9); generic_make_request(wbio2); } } /* * Used by fix_read_error() to decay the per rdev read_errors. * We halve the read error count for every hour that has elapsed * since the last recorded read error. * */ static void check_decay_read_errors(struct mddev *mddev, struct md_rdev *rdev) { struct timespec cur_time_mon; unsigned long hours_since_last; unsigned int read_errors = atomic_read(&rdev->read_errors); ktime_get_ts(&cur_time_mon); if (rdev->last_read_error.tv_sec == 0 && rdev->last_read_error.tv_nsec == 0) { /* first time we've seen a read error */ rdev->last_read_error = cur_time_mon; return; } hours_since_last = (cur_time_mon.tv_sec - rdev->last_read_error.tv_sec) / 3600; rdev->last_read_error = cur_time_mon; /* * if hours_since_last is > the number of bits in read_errors * just set read errors to 0. We do this to avoid * overflowing the shift of read_errors by hours_since_last. */ if (hours_since_last >= 8 * sizeof(read_errors)) atomic_set(&rdev->read_errors, 0); else atomic_set(&rdev->read_errors, read_errors >> hours_since_last); } static int r10_sync_page_io(struct md_rdev *rdev, sector_t sector, int sectors, struct page *page, int rw) { sector_t first_bad; int bad_sectors; if (is_badblock(rdev, sector, sectors, &first_bad, &bad_sectors) && (rw == READ || test_bit(WriteErrorSeen, &rdev->flags))) return -1; if (sync_page_io(rdev, sector, sectors << 9, page, rw, false)) /* success */ return 1; if (rw == WRITE) { set_bit(WriteErrorSeen, &rdev->flags); if (!test_and_set_bit(WantReplacement, &rdev->flags)) set_bit(MD_RECOVERY_NEEDED, &rdev->mddev->recovery); } /* need to record an error - either for the block or the device */ if (!rdev_set_badblocks(rdev, sector, sectors, 0)) md_error(rdev->mddev, rdev); return 0; } /* * 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(struct r10conf *conf, struct mddev *mddev, struct r10bio *r10_bio) { int sect = 0; /* Offset from r10_bio->sector */ int sectors = r10_bio->sectors; struct md_rdev*rdev; int max_read_errors = atomic_read(&mddev->max_corr_read_errors); int d = r10_bio->devs[r10_bio->read_slot].devnum; /* still own a reference to this rdev, so it cannot * have been cleared recently. */ rdev = conf->mirrors[d].rdev; if (test_bit(Faulty, &rdev->flags)) /* drive has already been failed, just ignore any more fix_read_error() attempts */ return; check_decay_read_errors(mddev, rdev); atomic_inc(&rdev->read_errors); if (atomic_read(&rdev->read_errors) > max_read_errors) { char b[BDEVNAME_SIZE]; bdevname(rdev->bdev, b); printk(KERN_NOTICE "md/raid10:%s: %s: Raid device exceeded " "read_error threshold [cur %d:max %d]\n", mdname(mddev), b, atomic_read(&rdev->read_errors), max_read_errors); printk(KERN_NOTICE "md/raid10:%s: %s: Failing raid device\n", mdname(mddev), b); md_error(mddev, conf->mirrors[d].rdev); return; } 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 { sector_t first_bad; int bad_sectors; d = r10_bio->devs[sl].devnum; rdev = rcu_dereference(conf->mirrors[d].rdev); if (rdev && test_bit(In_sync, &rdev->flags) && is_badblock(rdev, r10_bio->devs[sl].addr + sect, s, &first_bad, &bad_sectors) == 0) { atomic_inc(&rdev->nr_pending); rcu_read_unlock(); success = sync_page_io(rdev, r10_bio->devs[sl].addr + sect, s<<9, conf->tmppage, READ, false); 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, just mark the block * as bad on the first device to discourage future * reads. */ int dn = r10_bio->devs[r10_bio->read_slot].devnum; rdev = conf->mirrors[dn].rdev; if (!rdev_set_badblocks( rdev, r10_bio->devs[r10_bio->read_slot].addr + sect, s, 0)) md_error(mddev, rdev); break; } start = sl; /* write it back and re-read */ rcu_read_lock(); while (sl != r10_bio->read_slot) { char b[BDEVNAME_SIZE]; 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)) continue; atomic_inc(&rdev->nr_pending); rcu_read_unlock(); if (r10_sync_page_io(rdev, r10_bio->devs[sl].addr + sect, s<<9, conf->tmppage, WRITE) == 0) { /* Well, this device is dead */ printk(KERN_NOTICE "md/raid10:%s: read correction " "write failed" " (%d sectors at %llu on %s)\n", mdname(mddev), s, (unsigned long long)( sect + rdev->data_offset), bdevname(rdev->bdev, b)); printk(KERN_NOTICE "md/raid10:%s: %s: failing " "drive\n", mdname(mddev), bdevname(rdev->bdev, b)); } rdev_dec_pending(rdev, mddev); rcu_read_lock(); } sl = start; while (sl != r10_bio->read_slot) { char b[BDEVNAME_SIZE]; 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)) continue; atomic_inc(&rdev->nr_pending); rcu_read_unlock(); switch (r10_sync_page_io(rdev, r10_bio->devs[sl].addr + sect, s<<9, conf->tmppage, READ)) { case 0: /* Well, this device is dead */ printk(KERN_NOTICE "md/raid10:%s: unable to read back " "corrected sectors" " (%d sectors at %llu on %s)\n", mdname(mddev), s, (unsigned long long)( sect + rdev->data_offset), bdevname(rdev->bdev, b)); printk(KERN_NOTICE "md/raid10:%s: %s: failing " "drive\n", mdname(mddev), bdevname(rdev->bdev, b)); break; case 1: printk(KERN_INFO "md/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)); atomic_add(s, &rdev->corrected_errors); } rdev_dec_pending(rdev, mddev); rcu_read_lock(); } rcu_read_unlock(); sectors -= s; sect += s; } } static void bi_complete(struct bio *bio, int error) { complete((struct completion *)bio->bi_private); } static int submit_bio_wait(int rw, struct bio *bio) { struct completion event; rw |= REQ_SYNC; init_completion(&event); bio->bi_private = &event; bio->bi_end_io = bi_complete; submit_bio(rw, bio); wait_for_completion(&event); return test_bit(BIO_UPTODATE, &bio->bi_flags); } static int narrow_write_error(struct r10bio *r10_bio, int i) { struct bio *bio = r10_bio->master_bio; struct mddev *mddev = r10_bio->mddev; struct r10conf *conf = mddev->private; struct md_rdev *rdev = conf->mirrors[r10_bio->devs[i].devnum].rdev; /* bio has the data to be written to slot 'i' where * we just recently had a write error. * We repeatedly clone the bio and trim down to one block, * then try the write. Where the write fails we record * a bad block. * It is conceivable that the bio doesn't exactly align with * blocks. We must handle this. * * We currently own a reference to the rdev. */ int block_sectors; sector_t sector; int sectors; int sect_to_write = r10_bio->sectors; int ok = 1; if (rdev->badblocks.shift < 0) return 0; block_sectors = 1 << rdev->badblocks.shift; sector = r10_bio->sector; sectors = ((r10_bio->sector + block_sectors) & ~(sector_t)(block_sectors - 1)) - sector; while (sect_to_write) { struct bio *wbio; if (sectors > sect_to_write) sectors = sect_to_write; /* Write at 'sector' for 'sectors' */ wbio = bio_clone_mddev(bio, GFP_NOIO, mddev); md_trim_bio(wbio, sector - bio->bi_sector, sectors); wbio->bi_sector = (r10_bio->devs[i].addr+ rdev->data_offset+ (sector - r10_bio->sector)); wbio->bi_bdev = rdev->bdev; if (submit_bio_wait(WRITE, wbio) == 0) /* Failure! */ ok = rdev_set_badblocks(rdev, sector, sectors, 0) && ok; bio_put(wbio); sect_to_write -= sectors; sector += sectors; sectors = block_sectors; } return ok; } static void handle_read_error(struct mddev *mddev, struct r10bio *r10_bio) { int slot = r10_bio->read_slot; struct bio *bio; struct r10conf *conf = mddev->private; struct md_rdev *rdev = r10_bio->devs[slot].rdev; char b[BDEVNAME_SIZE]; unsigned long do_sync; int max_sectors; /* 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); } rdev_dec_pending(rdev, mddev); bio = r10_bio->devs[slot].bio; bdevname(bio->bi_bdev, b); r10_bio->devs[slot].bio = mddev->ro ? IO_BLOCKED : NULL; read_more: rdev = read_balance(conf, r10_bio, &max_sectors); if (rdev == NULL) { printk(KERN_ALERT "md/raid10:%s: %s: unrecoverable I/O" " read error for block %llu\n", mdname(mddev), b, (unsigned long long)r10_bio->sector); raid_end_bio_io(r10_bio); bio_put(bio); return; } do_sync = (r10_bio->master_bio->bi_rw & REQ_SYNC); if (bio) bio_put(bio); slot = r10_bio->read_slot; printk_ratelimited( KERN_ERR "md/raid10:%s: %s: redirecting" "sector %llu to another mirror\n", mdname(mddev), bdevname(rdev->bdev, b), (unsigned long long)r10_bio->sector); bio = bio_clone_mddev(r10_bio->master_bio, GFP_NOIO, mddev); md_trim_bio(bio, r10_bio->sector - bio->bi_sector, max_sectors); r10_bio->devs[slot].bio = bio; r10_bio->devs[slot].rdev = rdev; bio->bi_sector = r10_bio->devs[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; if (max_sectors < r10_bio->sectors) { /* Drat - have to split this up more