diff options
Diffstat (limited to 'drivers/md/raid10.c')
| -rw-r--r-- | drivers/md/raid10.c | 3584 |
1 files changed, 3584 insertions, 0 deletions
diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c new file mode 100644 index 00000000..a954c95d --- /dev/null +++ b/drivers/md/raid10.c @@ -0,0 +1,3584 @@ +/* + * 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 <linux/slab.h> +#include <linux/delay.h> +#include <linux/blkdev.h> +#include <linux/module.h> +#include <linux/seq_file.h> +#include <linux/ratelimit.h> +#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 int enough(struct r10conf *conf, int ignore); + +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); + } else { + /* If all other devices that store this block have + * failed, we want to return the error upwards rather + * than fail the last device. Here we redefine + * "uptodate" to mean "Don't want to retry" + */ + unsigned long flags; + spin_lock_irqsave(&conf->device_lock, flags); + if (!enough(conf, rdev->raid_disk)) + uptodate = 1; + spin_unlock_irqrestore(&conf->device_lock, flags); + } + if (uptodate) { + 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 + * This requires checking for end-of-chunk if near_copies != raid_disks, + * and for subordinate merge_bvec_fns if merge_check_needed. + */ +static int raid10_mergeable_bvec(struct request_queue *q, + struct bvec_merge_data *bvm, + struct bio_vec *biovec) +{ + struct mddev *mddev = q->queuedata; + struct r10conf *conf = mddev->private; + 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; + + if (conf->near_copies < conf->raid_disks) { + max = (chunk_sectors - ((sector & (chunk_sectors - 1)) + + bio_sectors)) << 9; + if (max < 0) + /* bio_add cannot handle a negative return */ + max = 0; + if (max <= biovec->bv_len && bio_sectors == 0) + return biovec->bv_len; + } else + max = biovec->bv_len; + + if (mddev->merge_check_needed) { + struct r10bio r10_bio; + int s; + r10_bio.sector = sector; + raid10_find_phys(conf, &r10_bio); + rcu_read_lock(); + for (s = 0; s < conf->copies; s++) { + int disk = r10_bio.devs[s].devnum; + struct md_rdev *rdev = rcu_dereference( + conf->mirrors[disk].rdev); + if (rdev && !test_bit(Faulty, &rdev->flags)) { + struct request_queue *q = + bdev_get_queue(rdev->bdev); + if (q->merge_bvec_fn) { + bvm->bi_sector = r10_bio.devs[s].addr + + rdev->data_offset; + bvm->bi_bdev = rdev->bdev; + max = min(max, q->merge_bvec_fn( + q, bvm, biovec)); + } + } + rdev = rcu_dereference(conf->mirrors[disk].replacement); + if (rdev && !test_bit(Faulty, &rdev->flags)) { + struct request_queue *q = + bdev_get_queue(rdev->bdev); + if (q->merge_bvec_fn) { + bvm->bi_sector = r10_bio.devs[s].addr + + rdev->data_offset; + bvm->bi_bdev = rdev->bdev; + max = min(max, q->merge_bvec_fn( + q, bvm, biovec)); + } + } + } + rcu_read_unlock(); + } + 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) || + test_bit(Unmerged, &rdev->flags) || + r10_bio->devs[slot].addr + sectors > rdev->recovery_offset) + rdev = rcu_dereference(conf->mirrors[disk].rdev); + if (rdev == NULL || + test_bit(Faulty, &rdev->flags) || + test_bit(Unmerged, &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 for the barrier to drop. + * However if there are already pending + * requests (preventing the barrier from + * rising completely), and the + * pre-process bio queue isn't empty, + * then don't wait, as we need to empty + * that queue to get the nr_pending + * count down. + */ + wait_event_lock_irq(conf->wait_barrier, + !conf->barrier || + (conf->nr_pending && + current->bio_list && + !bio_list_empty(current->bio_list)), + conf->resync_lock, + ); + conf->nr_waiting--; + } + conf->nr_pending++; + spin_unlock_irq(&conf->resync_lock); +} + +static void allow_barrier(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) + || test_bit(Unmerged, &rrdev->flags))) + rrdev = NULL; + + r10_bio->devs[i].bio = NULL; + r10_bio->devs[i].repl_bio = NULL; + if (!rdev || test_bit(Faulty, &rdev->flags) || + test_bit(Unmerged, &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; + struct request_queue *q = bdev_get_queue(rdev->bdev); + + if (mddev->recovery_cp < MaxSector) + /* only hot-add to in-sync arrays, as recovery is + * very different from resync + */ + return -EBUSY; + if (rdev->saved_raid_disk < 0 && !enough(conf, -1)) + return -EINVAL; + + if (rdev->raid_disk >= 0) + first = last = rdev->raid_disk; + + if (q->merge_bvec_fn) { + set_bit(Unmerged, &rdev->flags); + mddev->merge_check_needed = 1; + } + + 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); + conf->fullsync = 1; + rcu_assign_pointer(p->replacement, rdev); + break; + } + + disk_stack_limits(mddev->gendisk, rdev->bdev, + rdev->data_offset << 9); + + 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; + } + if (err == 0 && test_bit(Unmerged, &rdev->flags)) { + /* Some requests might not have seen this new + * merge_bvec_fn. We must wait for them to complete + * before merging the device fully. + * First we make sure any code which has tested + * our function has submitted the request, then + * we wait for all outstanding requests to complete. + */ + synchronize_sched(); + raise_barrier(conf, 0); + lower_barrier(conf); + clear_bit(Unmerged, &rdev->flags); + } + 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; + else + 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; + int vcnt; + + 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; + + vcnt = (r10_bio->sectors + (PAGE_SIZE >> 9) - 1) >> (PAGE_SHIFT - 9); + /* now find blocks with errors */ + for (i=0 ; i < conf->copies ; i++) { + int j, d; + + 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), + fbio->bi_io_vec[j].bv_len)) + 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; + + 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); + r10_bio->devs[r10_bio->read_slot].bio = IO_BLOCKED; + 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(Unmerged, &rdev->flags) && + 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); + r10_bio->devs[r10_bio->read_slot].bio + = IO_BLOCKED; + } + 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(Unmerged, &rdev->flags) || + !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, 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, 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. + */ + bio = r10_bio->devs[slot].bio; + bdevname(bio->bi_bdev, b); + bio_put(bio); + r10_bio->devs[slot].bio = NULL; + + if (mddev->ro == 0) { + freeze_array(conf); + fix_read_error(conf, mddev, r10_bio); + unfreeze_array(conf); + } else + r10_bio->devs[slot].bio = IO_BLOCKED; + + rdev_dec_pending(rdev, mddev); + +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); + return; + } + + do_sync = (r10_bio->master_bio->bi_rw & REQ_SYNC); + 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 */ + struct bio *mbio = r10_bio->master_bio; + int sectors_handled = + r10_bio->sector + max_sectors + - mbio->bi_sector; + r10_bio->sectors = max_sectors; + spin_lock_irq(&conf->device_lock); + if (mbio->bi_phys_segments == 0) + mbio->bi_phys_segments = 2; + else + mbio->bi_phys_segments++; + spin_unlock_irq(&conf->device_lock); + generic_make_request(bio); + + r10_bio = mempool_alloc(conf->r10bio_pool, + GFP_NOIO); + r10_bio->master_bio = mbio; + r10_bio->sectors = (mbio->bi_size >> 9) + - sectors_handled; + r10_bio->state = 0; + set_bit(R10BIO_ReadError, + &r10_bio->state); + r10_bio->mddev = mddev; + r10_bio->sector = mbio->bi_sector + + sectors_handled; + + goto read_more; + } else + generic_make_request(bio); +} + +static void handle_write_completed(struct r10conf *conf, struct r10bio *r10_bio) +{ + /* Some sort of write request has finished and it + * succeeded in writing where we thought there was a + * bad block. So forget the bad block. + * Or possibly if failed and we need to record + * a bad block. + */ + int m; + struct md_rdev *rdev; + + if (test_bit(R10BIO_IsSync, &r10_bio->state) || + test_bit(R10BIO_IsRecover, &r10_bio->state)) { + for (m = 0; m < conf->copies; m++) { + int dev = r10_bio->devs[m].devnum; + rdev = conf->mirrors[dev].rdev; + if (r10_bio->devs[m].bio == NULL) + continue; + if (test_bit(BIO_UPTODATE, + &r10_bio->devs[m].bio->bi_flags)) { + rdev_clear_badblocks( + rdev, + r10_bio->devs[m].addr, + r10_bio->sectors); + } else { + if (!rdev_set_badblocks( + rdev, + r10_bio->devs[m].addr, + r10_bio->sectors, 0)) + md_error(conf->mddev, rdev); + } + rdev = conf->mirrors[dev].replacement; + if (r10_bio->devs[m].repl_bio == NULL) + continue; + if (test_bit(BIO_UPTODATE, + &r10_bio->devs[m].repl_bio->bi_flags)) { + rdev_clear_badblocks( + rdev, + r10_bio->devs[m].addr, + r10_bio->sectors); + } else { + if (!rdev_set_badblocks( + rdev, + r10_bio->devs[m].addr, + r10_bio->sectors, 0)) + md_error(conf->mddev, rdev); + } + } + put_buf(r10_bio); + } else { + for (m = 0; m < conf->copies; m++) { + int dev = r10_bio->devs[m].devnum; + struct bio *bio = r10_bio->devs[m].bio; + rdev = conf->mirrors[dev].rdev; + if (bio == IO_MADE_GOOD) { + rdev_clear_badblocks( + rdev, + r10_bio->devs[m].addr, + r10_bio->sectors); + rdev_dec_pending(rdev, conf->mddev); + } else if (bio != NULL && + !test_bit(BIO_UPTODATE, &bio->bi_flags)) { + if (!narrow_write_error(r10_bio, m)) { + md_error(conf->mddev, rdev); + set_bit(R10BIO_Degraded, + &r10_bio->state); + } + rdev_dec_pending(rdev, conf->mddev); + } + bio = r10_bio->devs[m].repl_bio; + rdev = conf->mirrors[dev].replacement; + if (rdev && bio == IO_MADE_GOOD) { + rdev_clear_badblocks( + rdev, + r10_bio->devs[m].addr, + r10_bio->sectors); + rdev_dec_pending(rdev, conf->mddev); + } + } + if (test_bit(R10BIO_WriteError, + &r10_bio->state)) + close_write(r10_bio); + raid_end_bio_io(r10_bio); + } +} + +static void raid10d(struct mddev *mddev) +{ + struct r10bio *r10_bio; + unsigned long flags; + struct r10conf *conf = mddev->private; + struct list_head *head = &conf->retry_list; + struct blk_plug plug; + + md_check_recovery(mddev); + + blk_start_plug(&plug); + for (;;) { + + 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, struct r10bio, retry_list); + list_del(head->prev); + conf->nr_queued--; + spin_unlock_irqrestore(&conf->device_lock, flags); + + mddev = r10_bio->mddev; + conf = mddev->private; + if (test_bit(R10BIO_MadeGood, &r10_bio->state) || + test_bit(R10BIO_WriteError, &r10_bio->state)) + handle_write_completed(conf, r10_bio); + else if (test_bit(R10BIO_IsSync, &r10_bio->state)) + sync_request_write(mddev, r10_bio); + else if (test_bit(R10BIO_IsRecover, &r10_bio->state)) + recovery_request_write(mddev, r10_bio); + else if (test_bit(R10BIO_ReadError, &r10_bio->state)) + handle_read_error(mddev, r10_bio); + else { + /* just a partial read to be scheduled from a + * separate context + */ + int slot = r10_bio->read_slot; + generic_make_request(r10_bio->devs[slot].bio); + } + + cond_resched(); + if (mddev->flags & ~(1<<MD_CHANGE_PENDING)) + md_check_recovery(mddev); + } + blk_finish_plug(&plug); +} + + +static int init_resync(struct r10conf *conf) +{ + int buffs; + int i; + + buffs = RESYNC_WINDOW / RESYNC_BLOCK_SIZE; + BUG_ON(conf->r10buf_pool); + conf->have_replacement = 0; + for (i = 0; i < conf->raid_disks; i++) + if (conf->mirrors[i].replacement) + conf->have_replacement = 1; + 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(struct mddev *mddev, sector_t sector_nr, + int *skipped, int go_faster) +{ + struct r10conf *conf = mddev->private; + struct r10bio *r10_bio; + struct bio *biolist = NULL, *bio; + sector_t max_sector, nr_sectors; + int i; + int max_sync; + sector_t 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->dev_sectors; + 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 */ + if ((!mddev->bitmap || conf->fullsync) + && conf->have_replacement + && test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) { + /* Completed a full sync so the replacements + * are now fully recovered. + */ + for (i = 0; i < conf->raid_disks; i++) + if (conf->mirrors[i].replacement) + conf->mirrors[i].replacement + ->recovery_offset + = MaxSector; + } + 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); + + /* 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 j; + r10_bio = NULL; + + for (i=0 ; i<conf->raid_disks; i++) { + int still_degraded; + struct r10bio *rb2; + sector_t sect; + int must_sync; + int any_working; + struct mirror_info *mirror = &conf->mirrors[i]; + + if ((mirror->rdev == NULL || + test_bit(In_sync, &mirror->rdev->flags)) + && + (mirror->replacement == NULL || + test_bit(Faulty, + &mirror->replacement->flags))) + continue; + + still_degraded = 0; + /* want to reconstruct this device */ + rb2 = r10_bio; + sect = raid10_find_virt(conf, sector_nr, i); + if (sect >= mddev->resync_max_sectors) { + /* last stripe is not complete - don't + * try to recover this sector. + */ + continue; + } + /* Unless we are doing a full sync, or a replacement + * 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 && + mirror->replacement == NULL && + !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 the array will still be + * degraded + */ + for (j=0; j<conf->raid_disks; j++) + if (conf->mirrors[j].rdev == NULL || + test_bit(Faulty, &conf->mirrors[j].rdev->flags)) { + still_degraded = 1; + break; + } + + must_sync = bitmap_start_sync(mddev->bitmap, sect, + &sync_blocks, still_degraded); + + any_working = 0; + for (j=0; j<conf->copies;j++) { + int k; + int d = r10_bio->devs[j].devnum; + sector_t from_addr, to_addr; + struct md_rdev *rdev; + sector_t sector, first_bad; + int bad_sectors; + if (!conf->mirrors[d].rdev || + !test_bit(In_sync, &conf->mirrors[d].rdev->flags)) + continue; + /* This is where we read from */ + any_working = 1; + rdev = conf->mirrors[d].rdev; + sector = r10_bio->devs[j].addr; + + if (is_badblock(rdev, sector, max_sync, + &first_bad, &bad_sectors)) { + if (first_bad > sector) + max_sync = first_bad - sector; + else { + bad_sectors -= (sector + - first_bad); + if (max_sync > bad_sectors) + max_sync = bad_sectors; + continue; + } + } + 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; + from_addr = r10_bio->devs[j].addr; + bio->bi_sector = from_addr + rdev->data_offset; + bio->bi_bdev = rdev->bdev; + atomic_inc(&rdev->nr_pending); + /* and we write to 'i' (if not in_sync) */ + + for (k=0; k<conf->copies; k++) + if (r10_bio->devs[k].devnum == i) + break; + BUG_ON(k == conf->copies); + to_addr = r10_bio->devs[k].addr; + r10_bio->devs[0].devnum = d; + r10_bio->devs[0].addr = from_addr; + r10_bio->devs[1].devnum = i; + r10_bio->devs[1].addr = to_addr; + + rdev = mirror->rdev; + if (!test_bit(In_sync, &rdev->flags)) { + 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 = to_addr + + rdev->data_offset; + bio->bi_bdev = rdev->bdev; + atomic_inc(&r10_bio->remaining); + } else + r10_bio->devs[1].bio->bi_end_io = NULL; + + /* and maybe write to replacement */ + bio = r10_bio->devs[1].repl_bio; + if (bio) + bio->bi_end_io = NULL; + rdev = mirror->replacement; + /* Note: if rdev != NULL, then bio + * cannot be NULL as r10buf_pool_alloc will + * have allocated it. + * So the second test here is pointless. + * But it keeps semantic-checkers happy, and + * this comment keeps human reviewers + * happy. + */ + if (rdev == NULL || bio == NULL || + test_bit(Faulty, &rdev->flags)) + break; + 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 = to_addr + rdev->data_offset; + bio->bi_bdev = rdev->bdev; + atomic_inc(&r10_bio->remaining); + break; + } + if (j == conf->copies) { + /* Cannot recover, so abort the recovery or + * record a bad block */ + put_buf(r10_bio); + if (rb2) + atomic_dec(&rb2->remaining); + r10_bio = rb2; + if (any_working) { + /* problem is that there are bad blocks + * on other device(s) + */ + int k; + for (k = 0; k < conf->copies; k++) + if (r10_bio->devs[k].devnum == i) + break; + if (!test_bit(In_sync, + &mirror->rdev->flags) + && !rdev_set_badblocks( + mirror->rdev, + r10_bio->devs[k].addr, + max_sync, 0)) + any_working = 0; + if (mirror->replacement && + !rdev_set_badblocks( + mirror->replacement, + r10_bio->devs[k].addr, + max_sync, 0)) + any_working = 0; + } + if (!any_working) { + if (!test_and_set_bit(MD_RECOVERY_INTR, + &mddev->recovery)) + printk(KERN_INFO "md/raid10:%s: insufficient " + "working devices for recovery.\n", + mdname(mddev)); + mirror->recovery_disabled + = mddev->recovery_disabled; + } + break; + } + } + if (biolist == NULL) { + while (r10_bio) { + struct r10bio *rb2 = r10_bio; + r10_bio = (struct r10bio*) 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; + + bitmap_cond_end_sync(mddev->bitmap, sector_nr); + + 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; + sector_t first_bad, sector; + int bad_sectors; + + if (r10_bio->devs[i].repl_bio) + r10_bio->devs[i].repl_bio->bi_end_io = NULL; + + 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; + sector = r10_bio->devs[i].addr; + if (is_badblock(conf->mirrors[d].rdev, + sector, max_sync, + &first_bad, &bad_sectors)) { + if (first_bad > sector) + max_sync = first_bad - sector; + else { + bad_sectors -= (sector - first_bad); + if (max_sync > bad_sectors) + max_sync = max_sync; + 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 = sector + + conf->mirrors[d].rdev->data_offset; + bio->bi_bdev = conf->mirrors[d].rdev->bdev; + count++; + + if (conf->mirrors[d].replacement == NULL || + test_bit(Faulty, + &conf->mirrors[d].replacement->flags)) + continue; + + /* Need to set up for writing to the replacement */ + bio = r10_bio->devs[i].repl_bio; + clear_bit(BIO_UPTODATE, &bio->bi_flags); + + sector = r10_bio->devs[i].addr; + atomic_inc(&conf->mirrors[d].rdev->nr_pending); + 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 = sector + + conf->mirrors[d].replacement->data_offset; + bio->bi_bdev = conf->mirrors[d].replacement->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); + if (r10_bio->devs[i].repl_bio && + r10_bio->devs[i].repl_bio->bi_end_io) + rdev_dec_pending( + conf->mirrors[d].replacement, + 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; + 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) { + struct bio *bio2; + page = bio->bi_io_vec[bio->bi_vcnt].bv_page; + if (bio_add_page(bio, page, len, 0)) + continue; + + /* stop here */ + 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; + } + 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 or in resync, all drives + * have a bad block, so try the next chunk... + */ + if (sector_nr + max_sync < max_sector) + max_sector = sector_nr + max_sync; + + sectors_skipped += (max_sector - sector_nr); + chunks_skipped ++; + sector_nr = max_sector; + goto skipped; +} + +static sector_t +raid10_size(struct mddev *mddev, sector_t sectors, int raid_disks) +{ + sector_t size; + struct r10conf *conf = mddev->private; + + if (!raid_disks) + raid_disks = conf->raid_disks; + if (!sectors) + sectors = conf->dev_sectors; + + size = sectors >> conf->chunk_shift; + sector_div(size, conf->far_copies); + size = size * raid_disks; + sector_div(size, conf->near_copies); + + return size << conf->chunk_shift; +} + +static void calc_sectors(struct r10conf *conf, sector_t size) +{ + /* Calculate the number of sectors-per-device that will + * actually be used, and set conf->dev_sectors and + * conf->stride + */ + + size = size >> conf->chunk_shift; + sector_div(size, conf->far_copies); + size = size * conf->raid_disks; + sector_div(size, conf->near_copies); + /* 'size' is now the number of chunks in the array */ + /* calculate "used chunks per device" */ + size = size * conf->copies; + + /* We need to round up when dividing by raid_disks to + * get the stride size. + */ + size = DIV_ROUND_UP_SECTOR_T(size, conf->raid_disks); + + conf->dev_sectors = size << conf->chunk_shift; + + if (conf->far_offset) + conf->stride = 1 << conf->chunk_shift; + else { + sector_div(size, conf->far_copies); + conf->stride = size << conf->chunk_shift; + } +} + +static struct r10conf *setup_conf(struct mddev *mddev) +{ + struct r10conf *conf = NULL; + int nc, fc, fo; + int err = -EINVAL; + + if (mddev->new_chunk_sectors < (PAGE_SIZE >> 9) || + !is_power_of_2(mddev->new_chunk_sectors)) { + printk(KERN_ERR "md/raid10:%s: chunk size must be " + "at least PAGE_SIZE(%ld) and be a power of 2.\n", + mdname(mddev), PAGE_SIZE); + goto out; + } + + nc = mddev->new_layout & 255; + fc = (mddev->new_layout >> 8) & 255; + fo = mddev->new_layout & (1<<16); + + if ((nc*fc) <2 || (nc*fc) > mddev->raid_disks || + (mddev->new_layout >> 17)) { + printk(KERN_ERR "md/raid10:%s: unsupported raid10 layout: 0x%8x\n", + mdname(mddev), mddev->new_layout); + goto out; + } + + err = -ENOMEM; + conf = kzalloc(sizeof(struct r10conf), GFP_KERNEL); + if (!conf) + goto out; + + conf->mirrors = kzalloc(sizeof(struct mirror_info)*mddev->raid_disks, + GFP_KERNEL); + if (!conf->mirrors) + goto out; + + conf->tmppage = alloc_page(GFP_KERNEL); + if (!conf->tmppage) + goto out; + + + 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 = mddev->new_chunk_sectors - 1; + conf->chunk_shift = ffz(~mddev->new_chunk_sectors); + + conf->r10bio_pool = mempool_create(NR_RAID10_BIOS, r10bio_pool_alloc, + r10bio_pool_free, conf); + if (!conf->r10bio_pool) + goto out; + + calc_sectors(conf, mddev->dev_sectors); + + spin_lock_init(&conf->device_lock); + INIT_LIST_HEAD(&conf->retry_list); + + spin_lock_init(&conf->resync_lock); + init_waitqueue_head(&conf->wait_barrier); + + conf->thread = md_register_thread(raid10d, mddev, NULL); + if (!conf->thread) + goto out; + + conf->mddev = mddev; + return conf; + + out: + printk(KERN_ERR "md/raid10:%s: couldn't allocate memory.\n", + mdname(mddev)); + if (conf) { + if (conf->r10bio_pool) + mempool_destroy(conf->r10bio_pool); + kfree(conf->mirrors); + safe_put_page(conf->tmppage); + kfree(conf); + } + return ERR_PTR(err); +} + +static int run(struct mddev *mddev) +{ + struct r10conf *conf; + int i, disk_idx, chunk_size; + struct mirror_info *disk; + struct md_rdev *rdev; + sector_t size; + + /* + * copy the already verified devices into our private RAID10 + * bookkeeping area. [whatever we allocate in run(), + * should be freed in stop()] + */ + + if (mddev->private == NULL) { + conf = setup_conf(mddev); + if (IS_ERR(conf)) + return PTR_ERR(conf); + mddev->private = conf; + } + conf = mddev->private; + if (!conf) + goto out; + + mddev->thread = conf->thread; + conf->thread = NULL; + + chunk_size = mddev->chunk_sectors << 9; + blk_queue_io_min(mddev->queue, chunk_size); + if (conf->raid_disks % conf->near_copies) + blk_queue_io_opt(mddev->queue, chunk_size * conf->raid_disks); + else + blk_queue_io_opt(mddev->queue, chunk_size * + (conf->raid_disks / conf->near_copies)); + + rdev_for_each(rdev, mddev) { + struct request_queue *q; + disk_idx = rdev->raid_disk; + if (disk_idx >= conf->raid_disks + || disk_idx < 0) + continue; + disk = conf->mirrors + disk_idx; + + if (test_bit(Replacement, &rdev->flags)) { + if (disk->replacement) + goto out_free_conf; + disk->replacement = rdev; + } else { + if (disk->rdev) + goto out_free_conf; + disk->rdev = rdev; + } + q = bdev_get_queue(rdev->bdev); + if (q->merge_bvec_fn) + mddev->merge_check_needed = 1; + + disk_stack_limits(mddev->gendisk, rdev->bdev, + rdev->data_offset << 9); + + disk->head_position = 0; + } + /* need to check that every block has at least one working mirror */ + if (!enough(conf, -1)) { + printk(KERN_ERR "md/raid10:%s: not enough operational mirrors.\n", + mdname(mddev)); + goto out_free_conf; + } + + mddev->degraded = 0; + for (i = 0; i < conf->raid_disks; i++) { + + disk = conf->mirrors + i; + + if (!disk->rdev && disk->replacement) { + /* The replacement is all we have - use it */ + disk->rdev = disk->replacement; + disk->replacement = NULL; + clear_bit(Replacement, &disk->rdev->flags); + } + + if (!disk->rdev || + !test_bit(In_sync, &disk->rdev->flags)) { + disk->head_position = 0; + mddev->degraded++; + if (disk->rdev) + conf->fullsync = 1; + } + disk->recovery_disabled = mddev->recovery_disabled - 1; + } + + if (mddev->recovery_cp != MaxSector) + printk(KERN_NOTICE "md/raid10:%s: not clean" + " -- starting background reconstruction\n", + mdname(mddev)); + printk(KERN_INFO + "md/raid10:%s: active with %d out of %d devices\n", + mdname(mddev), conf->raid_disks - mddev->degraded, + conf->raid_disks); + /* + * Ok, everything is just fine now + */ + mddev->dev_sectors = conf->dev_sectors; + size = raid10_size(mddev, 0, 0); + md_set_array_sectors(mddev, size); + mddev->resync_max_sectors = size; + + 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_sectors << 9) / 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; + } + + blk_queue_merge_bvec(mddev->queue, raid10_mergeable_bvec); + + if (md_integrity_register(mddev)) + goto out_free_conf; + + return 0; + +out_free_conf: + md_unregister_thread(&mddev->thread); + 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(struct mddev *mddev) +{ + struct r10conf *conf = mddev->private; + + raise_barrier(conf, 0); + lower_barrier(conf); + + md_unregister_thread(&mddev->thread); + 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(struct mddev *mddev, int state) +{ + struct r10conf *conf = mddev->private; + + switch(state) { + case 1: + raise_barrier(conf, 0); + break; + case 0: + lower_barrier(conf); + break; + } +} + +static int raid10_resize(struct mddev *mddev, sector_t sectors) +{ + /* Resize of 'far' arrays is not supported. + * For 'near' and 'offset' arrays we can set the + * number of sectors used to be an appropriate multiple + * of the chunk size. + * For 'offset', this is far_copies*chunksize. + * For 'near' the multiplier is the LCM of + * near_copies and raid_disks. + * So if far_copies > 1 && !far_offset, fail. + * Else find LCM(raid_disks, near_copy)*far_copies and + * multiply by chunk_size. Then round to this number. + * This is mostly done by raid10_size() + */ + struct r10conf *conf = mddev->private; + sector_t oldsize, size; + + if (conf->far_copies > 1 && !conf->far_offset) + return -EINVAL; + + oldsize = raid10_size(mddev, 0, 0); + size = raid10_size(mddev, sectors, 0); + md_set_array_sectors(mddev, size); + if (mddev->array_sectors > size) + return -EINVAL; + set_capacity(mddev->gendisk, mddev->array_sectors); + revalidate_disk(mddev->gendisk); + if (sectors > mddev->dev_sectors && + mddev->recovery_cp > oldsize) { + mddev->recovery_cp = oldsize; + set_bit(MD_RECOVERY_NEEDED, &mddev->recovery); + } + calc_sectors(conf, sectors); + mddev->dev_sectors = conf->dev_sectors; + mddev->resync_max_sectors = size; + return 0; +} + +static void *raid10_takeover_raid0(struct mddev *mddev) +{ + struct md_rdev *rdev; + struct r10conf *conf; + + if (mddev->degraded > 0) { + printk(KERN_ERR "md/raid10:%s: Error: degraded raid0!\n", + mdname(mddev)); + return ERR_PTR(-EINVAL); + } + + /* Set new parameters */ + mddev->new_level = 10; + /* new layout: far_copies = 1, near_copies = 2 */ + mddev->new_layout = (1<<8) + 2; + mddev->new_chunk_sectors = mddev->chunk_sectors; + mddev->delta_disks = mddev->raid_disks; + mddev->raid_disks *= 2; + /* make sure it will be not marked as dirty */ + mddev->recovery_cp = MaxSector; + + conf = setup_conf(mddev); + if (!IS_ERR(conf)) { + rdev_for_each(rdev, mddev) + if (rdev->raid_disk >= 0) + rdev->new_raid_disk = rdev->raid_disk * 2; + conf->barrier = 1; + } + + return conf; +} + +static void *raid10_takeover(struct mddev *mddev) +{ + struct r0conf *raid0_conf; + + /* raid10 can take over: + * raid0 - providing it has only two drives + */ + if (mddev->level == 0) { + /* for raid0 takeover only one zone is supported */ + raid0_conf = mddev->private; + if (raid0_conf->nr_strip_zones > 1) { + printk(KERN_ERR "md/raid10:%s: cannot takeover raid 0" + " with more than one zone.\n", + mdname(mddev)); + return ERR_PTR(-EINVAL); + } + return raid10_takeover_raid0(mddev); + } + return ERR_PTR(-EINVAL); +} + +static struct md_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, + .size = raid10_size, + .resize = raid10_resize, + .takeover = raid10_takeover, +}; + +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_DESCRIPTION("RAID10 (striped mirror) personality for MD"); +MODULE_ALIAS("md-personality-9"); /* RAID10 */ +MODULE_ALIAS("md-raid10"); +MODULE_ALIAS("md-level-10"); + +module_param(max_queued_requests, int, S_IRUGO|S_IWUSR); |