/* * raid1.c : Multiple Devices driver for Linux * * Copyright (C) 1999, 2000, 2001 Ingo Molnar, Red Hat * * Copyright (C) 1996, 1997, 1998 Ingo Molnar, Miguel de Icaza, Gadi Oxman * * RAID-1 management functions. * * Better read-balancing code written by Mika Kuoppala <miku@iki.fi>, 2000 * * Fixes to reconstruction by Jakob Østergaard" <jakob@ostenfeld.dk> * Various fixes by Neil Brown <neilb@cse.unsw.edu.au> * * Changes by Peter T. Breuer <ptb@it.uc3m.es> 31/1/2003 to support * bitmapped intelligence in resync: * * - bitmap marked during normal i/o * - bitmap used to skip nondirty blocks during sync * * Additions to bitmap code, (C) 2003-2004 Paul Clements, SteelEye Technology: * - persistent bitmap code * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2, or (at your option) * any later version. * * You should have received a copy of the GNU General Public License * (for example /usr/src/linux/COPYING); if not, write to the Free * Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */ #include "dm-bio-list.h" #include <linux/raid/raid1.h> #include <linux/raid/bitmap.h> #define DEBUG 0 #if DEBUG #define PRINTK(x...) printk(x) #else #define PRINTK(x...) #endif /* * Number of guaranteed r1bios in case of extreme VM load: */ #define NR_RAID1_BIOS 256 static void unplug_slaves(mddev_t *mddev); static void allow_barrier(conf_t *conf); static void lower_barrier(conf_t *conf); static void * r1bio_pool_alloc(gfp_t gfp_flags, void *data) { struct pool_info *pi = data; r1bio_t *r1_bio; int size = offsetof(r1bio_t, bios[pi->raid_disks]); /* allocate a r1bio with room for raid_disks entries in the bios array */ r1_bio = kzalloc(size, gfp_flags); if (!r1_bio) unplug_slaves(pi->mddev); return r1_bio; } static void r1bio_pool_free(void *r1_bio, void *data) { kfree(r1_bio); } #define RESYNC_BLOCK_SIZE (64*1024) //#define RESYNC_BLOCK_SIZE PAGE_SIZE #define RESYNC_SECTORS (RESYNC_BLOCK_SIZE >> 9) #define RESYNC_PAGES ((RESYNC_BLOCK_SIZE + PAGE_SIZE-1) / PAGE_SIZE) #define RESYNC_WINDOW (2048*1024) static void * r1buf_pool_alloc(gfp_t gfp_flags, void *data) { struct pool_info *pi = data; struct page *page; r1bio_t *r1_bio; struct bio *bio; int i, j; r1_bio = r1bio_pool_alloc(gfp_flags, pi); if (!r1_bio) { unplug_slaves(pi->mddev); return NULL; } /* * Allocate bios : 1 for reading, n-1 for writing */ for (j = pi->raid_disks ; j-- ; ) { bio = bio_alloc(gfp_flags, RESYNC_PAGES); if (!bio) goto out_free_bio; r1_bio->bios[j] = bio; } /* * Allocate RESYNC_PAGES data pages and attach them to * the first bio. * If this is a user-requested check/repair, allocate * RESYNC_PAGES for each bio. */ if (test_bit(MD_RECOVERY_REQUESTED, &pi->mddev->recovery)) j = pi->raid_disks; else j = 1; while(j--) { bio = r1_bio->bios[j]; for (i = 0; i < RESYNC_PAGES; i++) { page = alloc_page(gfp_flags); if (unlikely(!page)) goto out_free_pages; bio->bi_io_vec[i].bv_page = page; } } /* If not user-requests, copy the page pointers to all bios */ if (!test_bit(MD_RECOVERY_REQUESTED, &pi->mddev->recovery)) { for (i=0; i<RESYNC_PAGES ; i++) for (j=1; j<pi->raid_disks; j++) r1_bio->bios[j]->bi_io_vec[i].bv_page = r1_bio->bios[0]->bi_io_vec[i].bv_page; } r1_bio->master_bio = NULL; return r1_bio; out_free_pages: for (i=0; i < RESYNC_PAGES ; i++) for (j=0 ; j < pi->raid_disks; j++) safe_put_page(r1_bio->bios[j]->bi_io_vec[i].bv_page); j = -1; out_free_bio: while ( ++j < pi->raid_disks ) bio_put(r1_bio->bios[j]); r1bio_pool_free(r1_bio, data); return NULL; } static void r1buf_pool_free(void *__r1_bio, void *data) { struct pool_info *pi = data; int i,j; r1bio_t *r1bio = __r1_bio; for (i = 0; i < RESYNC_PAGES; i++) for (j = pi->raid_disks; j-- ;) { if (j == 0 || r1bio->bios[j]->bi_io_vec[i].bv_page != r1bio->bios[0]->bi_io_vec[i].bv_page) safe_put_page(r1bio->bios[j]->bi_io_vec[i].bv_page); } for (i=0 ; i < pi->raid_disks; i++) bio_put(r1bio->bios[i]); r1bio_pool_free(r1bio, data); } static void put_all_bios(conf_t *conf, r1bio_t *r1_bio) { int i; for (i = 0; i < conf->raid_disks; i++) { struct bio **bio = r1_bio->bios + i; if (*bio && *bio != IO_BLOCKED) bio_put(*bio); *bio = NULL; } } static void free_r1bio(r1bio_t *r1_bio) { conf_t *conf = mddev_to_conf(r1_bio->mddev); /* * Wake up any possible resync thread that waits for the device * to go idle. */ allow_barrier(conf); put_all_bios(conf, r1_bio); mempool_free(r1_bio, conf->r1bio_pool); } static void put_buf(r1bio_t *r1_bio) { conf_t *conf = mddev_to_conf(r1_bio->mddev); int i; for (i=0; i<conf->raid_disks; i++) { struct bio *bio = r1_bio->bios[i]; if (bio->bi_end_io) rdev_dec_pending(conf->mirrors[i].rdev, r1_bio->mddev); } mempool_free(r1_bio, conf->r1buf_pool); lower_barrier(conf); } static void reschedule_retry(r1bio_t *r1_bio) { unsigned long flags; mddev_t *mddev = r1_bio->mddev; conf_t *conf = mddev_to_conf(mddev); spin_lock_irqsave(&conf->device_lock, flags); list_add(&r1_bio->retry_list, &conf->retry_list); conf->nr_queued ++; spin_unlock_irqrestore(&conf->device_lock, flags); wake_up(&conf->wait_barrier); md_wakeup_thread(mddev->thread); } /* * raid_end_bio_io() is called when we have finished servicing a mirrored * operation and are ready to return a success/failure code to the buffer * cache layer. */ static void raid_end_bio_io(r1bio_t *r1_bio) { struct bio *bio = r1_bio->master_bio; /* if nobody has done the final endio yet, do it now */ if (!test_and_set_bit(R1BIO_Returned, &r1_bio->state)) { PRINTK(KERN_DEBUG "raid1: sync end %s on sectors %llu-%llu\n", (bio_data_dir(bio) == WRITE) ? "write" : "read", (unsigned long long) bio->bi_sector, (unsigned long long) bio->bi_sector + (bio->bi_size >> 9) - 1); bio_endio(bio, test_bit(R1BIO_Uptodate, &r1_bio->state) ? 0 : -EIO); } free_r1bio(r1_bio); } /* * Update disk head position estimator based on IRQ completion info. */ static inline void update_head_pos(int disk, r1bio_t *r1_bio) { conf_t *conf = mddev_to_conf(r1_bio->mddev); conf->mirrors[disk].head_position = r1_bio->sector + (r1_bio->sectors); } static void raid1_end_read_request(struct bio *bio, int error) { int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags); r1bio_t * r1_bio = (r1bio_t *)(bio->bi_private); int mirror; conf_t *conf = mddev_to_conf(r1_bio->mddev); mirror = r1_bio->read_disk; /* * this branch is our 'one mirror IO has finished' event handler: */ update_head_pos(mirror, r1_bio); if (uptodate) set_bit(R1BIO_Uptodate, &r1_bio->state); else { /* If all other devices have failed, we want to return * the error upwards rather than fail the last device. * Here we redefine "uptodate" to mean "Don't want to retry" */ unsigned long flags; spin_lock_irqsave(&conf->device_lock, flags); if (r1_bio->mddev->degraded == conf->raid_disks || (r1_bio->mddev->degraded == conf->raid_disks-1 && !test_bit(Faulty, &conf->mirrors[mirror].rdev->flags))) uptodate = 1; spin_unlock_irqrestore(&conf->device_lock, flags); } if (uptodate) raid_end_bio_io(r1_bio); else { /* * oops, read error: */ char b[BDEVNAME_SIZE]; if (printk_ratelimit()) printk(KERN_ERR "raid1: %s: rescheduling sector %llu\n", bdevname(conf->mirrors[mirror].rdev->bdev,b), (unsigned long long)r1_bio->sector); reschedule_retry(r1_bio); } rdev_dec_pending(conf->mirrors[mirror].rdev, conf->mddev); } static void raid1_end_write_request(struct bio *bio, int error) { int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags); r1bio_t * r1_bio = (r1bio_t *)(bio->bi_private); int mirror, behind = test_bit(R1BIO_BehindIO, &r1_bio->state); conf_t *conf = mddev_to_conf(r1_bio->mddev); struct bio *to_put = NULL; for (mirror = 0; mirror < conf->raid_disks; mirror++) if (r1_bio->bios[mirror] == bio) break; if (error == -EOPNOTSUPP && test_bit(R1BIO_Barrier, &r1_bio->state)) { set_bit(BarriersNotsupp, &conf->mirrors[mirror].rdev->flags); set_bit(R1BIO_BarrierRetry, &r1_bio->state); r1_bio->mddev->barriers_work = 0; /* Don't rdev_dec_pending in this branch - keep it for the retry */ } else { /* * this branch is our 'one mirror IO has finished' event handler: */ r1_bio->bios[mirror] = NULL; to_put = bio; if (!uptodate) { md_error(r1_bio->mddev, conf->mirrors[mirror].rdev); /* an I/O failed, we can't clear the bitmap */ set_bit(R1BIO_Degraded, &r1_bio->state); } else /* * Set R1BIO_Uptodate in our master bio, so that * we will return a good error code for to the higher * levels even if IO on some other mirrored buffer fails. * * The 'master' represents the composite IO operation to * user-side. So if something waits for IO, then it will * wait for the 'master' bio. */ set_bit(R1BIO_Uptodate, &r1_bio->state); update_head_pos(mirror, r1_bio); if (behind) { if (test_bit(WriteMostly, &conf->mirrors[mirror].rdev->flags)) atomic_dec(&r1_bio->behind_remaining); /* In behind mode, we ACK the master bio once the I/O has safely * reached all non-writemostly disks. Setting the Returned bit * ensures that this gets done only once -- we don't ever want to * return -EIO here, instead we'll wait */ if (atomic_read(&r1_bio->behind_remaining) >= (atomic_read(&r1_bio->remaining)-1) && test_bit(R1BIO_Uptodate, &r1_bio->state)) { /* Maybe we can return now */ if (!test_and_set_bit(R1BIO_Returned, &r1_bio->state)) { struct bio *mbio = r1_bio->master_bio; PRINTK(KERN_DEBUG "raid1: behind end write sectors %llu-%llu\n", (unsigned long long) mbio->bi_sector, (unsigned long long) mbio->bi_sector + (mbio->bi_size >> 9) - 1); bio_endio(mbio, 0); } } } rdev_dec_pending(conf->mirrors[mirror].rdev, conf->mddev); } /* * * Let's see if all mirrored write operations have finished * already. */ if (atomic_dec_and_test(&r1_bio->remaining)) { if (test_bit(R1BIO_BarrierRetry, &r1_bio->state)) reschedule_retry(r1_bio); else { /* it really is the end of this request */ if (test_bit(R1BIO_BehindIO, &r1_bio->state)) { /* free extra copy of the data pages */ int i = bio->bi_vcnt; while (i--) safe_put_page(bio->bi_io_vec[i].bv_page); } /* clear the bitmap if all writes complete successfully */ bitmap_endwrite(r1_bio->mddev->bitmap, r1_bio->sector, r1_bio->sectors, !test_bit(R1BIO_Degraded, &r1_bio->state), behind); md_write_end(r1_bio->mddev); raid_end_bio_io(r1_bio); } } if (to_put) bio_put(to_put); } /* * This routine returns the disk from which the requested read should * be done. There is a per-array 'next expected sequential IO' sector * number - if this matches on the next IO then we use the last disk. * There is also a per-disk 'last know head position' sector that is * maintained from IRQ contexts, both the normal and the resync IO * completion handlers update this position correctly. If there is no * perfect sequential match then we pick the disk whose head is closest. * * If there are 2 mirrors in the same 2 devices, performance degrades * because position is mirror, not device based. * * The rdev for the device selected will have nr_pending incremented. */ static int read_balance(conf_t *conf, r1bio_t *r1_bio) { const unsigned long this_sector = r1_bio->sector; int new_disk = conf->last_used, disk = new_disk; int wonly_disk = -1; const int sectors = r1_bio->sectors; sector_t new_distance, current_distance; mdk_rdev_t *rdev; rcu_read_lock(); /* * Check if we can balance. We can balance on the whole * device if no resync is going on, or below the resync window. * We take the first readable disk when above the resync window. */ retry: if (conf->mddev->recovery_cp < MaxSector && (this_sector + sectors >= conf->next_resync)) { /* Choose the first operation device, for consistancy */ new_disk = 0; for (rdev = rcu_dereference(conf->mirrors[new_disk].rdev); r1_bio->bios[new_disk] == IO_BLOCKED || !rdev || !test_bit(In_sync, &rdev->flags) || test_bit(WriteMostly, &rdev->flags); rdev = rcu_dereference(conf->mirrors[++new_disk].rdev)) { if (rdev && test_bit(In_sync, &rdev->flags) && r1_bio->bios[new_disk] != IO_BLOCKED) wonly_disk = new_disk; if (new_disk == conf->raid_disks - 1) { new_disk = wonly_disk; break; } } goto rb_out; } /* make sure the disk is operational */ for (rdev = rcu_dereference(conf->mirrors[new_disk].rdev); r1_bio->bios[new_disk] == IO_BLOCKED || !rdev || !test_bit(In_sync, &rdev->flags) || test_bit(WriteMostly, &rdev->flags); rdev = rcu_dereference(conf->mirrors[new_disk].rdev)) { if (rdev && test_bit(In_sync, &rdev->flags) && r1_bio->bios[new_disk] != IO_BLOCKED) wonly_disk = new_disk; if (new_disk <= 0) new_disk = conf->raid_disks; new_disk--; if (new_disk == disk) { new_disk = wonly_disk; break; } } if (new_disk < 0) goto rb_out; disk = new_disk; /* now disk == new_disk == starting point for search */ /* * Don't change to another disk for sequential reads: */ if (conf->next_seq_sect == this_sector) goto rb_out; if (this_sector == conf->mirrors[new_disk].head_position) goto rb_out; current_distance = abs(this_sector - conf->mirrors[disk].head_position); /* Find the disk whose head is closest */ do { if (disk <= 0) disk = conf->raid_disks; disk--; rdev = rcu_dereference(conf->mirrors[disk].rdev); if (!rdev || r1_bio->bios[disk] == IO_BLOCKED || !test_bit(In_sync, &rdev->flags) || test_bit(WriteMostly, &rdev->flags)) continue; if (!atomic_read(&rdev->nr_pending)) { new_disk = disk; break; } new_distance = abs(this_sector - conf->mirrors[disk].head_position); if (new_distance < current_distance) { current_distance = new_distance; new_disk = disk; } } while (disk != conf->last_used); rb_out: if (new_disk >= 0) { rdev = rcu_dereference(conf->mirrors[new_disk].rdev); if (!rdev) goto retry; atomic_inc(&rdev->nr_pending); if (!test_bit(In_sync, &rdev->flags)) { /* cannot risk returning a device that failed * before we inc'ed nr_pending */ rdev_dec_pending(rdev, conf->mddev); goto retry; } conf->next_seq_sect = this_sector + sectors; conf->last_used = new_disk; } rcu_read_unlock(); return new_disk; } static void unplug_slaves(mddev_t *mddev) { conf_t *conf = mddev_to_conf(mddev); int i; rcu_read_lock(); for (i=0; i<mddev->raid_disks; i++) { mdk_rdev_t *rdev = rcu_dereference(conf->mirrors[i].rdev); if (rdev && !test_bit(Faulty, &rdev->flags) && atomic_read(&rdev->nr_pending)) { struct request_queue *r_queue = bdev_get_queue(rdev->bdev); atomic_inc(&rdev->nr_pending); rcu_read_unlock(); blk_unplug(r_queue); rdev_dec_pending(rdev, mddev); rcu_read_lock(); } } rcu_read_unlock(); } static void raid1_unplug(struct request_queue *q) { mddev_t *mddev = q->queuedata; unplug_slaves(mddev); md_wakeup_thread(mddev->thread); } static int raid1_congested(void *data, int bits) { mddev_t *mddev = data; conf_t *conf = mddev_to_conf(mddev); int i, ret = 0; rcu_read_lock(); for (i = 0; i < mddev->raid_disks; i++) { mdk_rdev_t *rdev = rcu_dereference(conf->mirrors[i].rdev); if (rdev && !test_bit(Faulty, &rdev->flags)) { struct request_queue *q = bdev_get_queue(rdev->bdev); /* Note the '|| 1' - when read_balance prefers * non-congested targets, it can be removed */ if ((bits & (1<<BDI_write_congested)) || 1) ret |= bdi_congested(&q->backing_dev_info, bits); else ret &= bdi_congested(&q->backing_dev_info, bits); } } rcu_read_unlock(); return ret; } static int flush_pending_writes(conf_t *conf) { /* Any writes that have been queued but are awaiting * bitmap updates get flushed here. * We return 1 if any requests were actually submitted. */ int rv = 0; spin_lock_irq(&conf->device_lock); if (conf->pending_bio_list.head) { struct bio *bio; bio = bio_list_get(&conf->pending_bio_list); blk_remove_plug(conf->mddev->queue); spin_unlock_irq(&conf->device_lock); /* flush any pending bitmap writes to * disk before proceeding w/ I/O */ bitmap_unplug(conf->mddev->bitmap); while (bio) { /* submit pending writes */ struct bio *next = bio->bi_next; bio->bi_next = NULL; generic_make_request(bio); bio = next; } rv = 1; } else spin_unlock_irq(&conf->device_lock); return rv; } /* Barriers.... * Sometimes we need to suspend IO while we do something else, * either some resync/recovery, or reconfigure the array. * To do this we raise a 'barrier'. * The 'barrier' is a counter that can be raised multiple times * to count how many activities are happening which preclude * normal IO. * We can only raise the barrier if there is no pending IO. * i.e. if nr_pending == 0. * We choose only to raise the barrier if no-one is waiting for the * barrier to go down. This means that as soon as an IO request * is ready, no other operations which require a barrier will start * until the IO request has had a chance. * * So: regular IO calls 'wait_barrier'. When that returns there * is no backgroup IO happening, It must arrange to call * allow_barrier when it has finished its IO. * backgroup IO calls must call raise_barrier. Once that returns * there is no normal IO happeing. It must arrange to call * lower_barrier when the particular background IO completes. */ #define RESYNC_DEPTH 32 static void raise_barrier(conf_t *conf) { spin_lock_irq(&conf->resync_lock); /* Wait until no block IO is waiting */ wait_event_lock_irq(conf->wait_barrier, !conf->nr_waiting, conf->resync_lock, raid1_unplug(conf->mddev->queue)); /* block any new IO from starting */ conf->barrier++; /* No wait for all pending IO to complete */ wait_event_lock_irq(conf->wait_barrier, !conf->nr_pending && conf->barrier < RESYNC_DEPTH, conf->resync_lock, raid1_unplug(conf->mddev->queue)); spin_unlock_irq(&conf->resync_lock); } static void lower_barrier(conf_t *conf) { unsigned long flags; spin_lock_irqsave(&conf->resync_lock, flags); conf->barrier--; spin_unlock_irqrestore(&conf->resync_lock, flags); wake_up(&conf->wait_barrier); } static void wait_barrier(conf_t *conf) { spin_lock_irq(&conf->resync_lock); if (conf->barrier) { conf->nr_waiting++; wait_event_lock_irq(conf->wait_barrier, !conf->barrier, conf->resync_lock, raid1_unplug(conf->mddev->queue)); conf->nr_waiting--; } conf->nr_pending++; spin_unlock_irq(&conf->resync_lock); } static void allow_barrier(conf_t *conf) { unsigned long flags; spin_lock_irqsave(&conf->resync_lock, flags); conf->nr_pending--; spin_unlock_irqrestore(&conf->resync_lock, flags); wake_up(&conf->wait_barrier); } static void freeze_array(conf_t *conf) { /* stop syncio and normal IO and wait for everything to * go quite. * We increment barrier and nr_waiting, and then * wait until nr_pending match nr_queued+1 * This is called in the context of one normal IO request * that has failed. Thus any sync request that might be pending * will be blocked by nr_pending, and we need to wait for * pending IO requests to complete or be queued for re-try. * Thus the number queued (nr_queued) plus this request (1) * must match the number of pending IOs (nr_pending) before * we continue. */ spin_lock_irq(&conf->resync_lock); conf->barrier++; conf->nr_waiting++; wait_event_lock_irq(conf->wait_barrier, conf->nr_pending == conf->nr_queued+1, conf->resync_lock, ({ flush_pending_writes(conf); raid1_unplug(conf->mddev->queue); })); spin_unlock_irq(&conf->resync_lock); } static void unfreeze_array(conf_t *conf) { /* reverse the effect of the freeze */ spin_lock_irq(&conf->resync_lock); conf->barrier--; conf->nr_waiting--; wake_up(&conf->wait_barrier); spin_unlock_irq(&conf->resync_lock); } /* duplicate the data pages for behind I/O */ static struct page **alloc_behind_pages(struct bio *bio) { int i; struct bio_vec *bvec; struct page **pages = kzalloc(bio->bi_vcnt * sizeof(struct page *), GFP_NOIO); if (unlikely(!pages)) goto do_sync_io; bio_for_each_segment(bvec, bio, i) { pages[i] = alloc_page(GFP_NOIO); if (unlikely(!pages[i])) goto do_sync_io; memcpy(kmap(pages[i]) + bvec->bv_offset, kmap(bvec->bv_page) + bvec->bv_offset, bvec->bv_len); kunmap(pages[i]); kunmap(bvec->bv_page); } return pages; do_sync_io: if (pages) for (i = 0; i < bio->bi_vcnt && pages[i]; i++) put_page(pages[i]); kfree(pages); PRINTK("%dB behind alloc failed, doing sync I/O\n", bio->bi_size); return NULL; } static int make_request(struct request_queue *q, struct bio * bio) { mddev_t *mddev = q->queuedata; conf_t *conf = mddev_to_conf(mddev); mirror_info_t *mirror; r1bio_t *r1_bio; struct bio *read_bio; int i, targets = 0, disks; struct bitmap *bitmap; unsigned long flags; struct bio_list bl; struct page **behind_pages = NULL; const int rw = bio_data_dir(bio); const int do_sync = bio_sync(bio); int do_barriers; mdk_rdev_t *blocked_rdev; /* * Register the new request and wait if the reconstruction * thread has put up a bar for new requests. * Continue immediately if no resync is active currently. * We test barriers_work *after* md_write_start as md_write_start * may cause the first superblock write, and that will check out * if barriers work. */ md_write_start(mddev, bio); /* wait on superblock update early */ if (unlikely(!mddev->barriers_work && bio_barrier(bio))) { if (rw == WRITE) md_write_end(mddev); bio_endio(bio, -EOPNOTSUPP); return 0; } wait_barrier(conf); bitmap = mddev->bitmap; disk_stat_inc(mddev->gendisk, ios[rw]); disk_stat_add(mddev->gendisk, sectors[rw], bio_sectors(bio)); /* * make_request() can abort the operation when READA is being * used and no empty request is available. * */ r1_bio = mempool_alloc(conf->r1bio_pool, GFP_NOIO); r1_bio->master_bio = bio; r1_bio->sectors = bio->bi_size >> 9; r1_bio->state = 0; r1_bio->mddev = mddev; r1_bio->sector = bio->bi_sector; if (rw == READ) { /* * read balancing logic: */ int rdisk = read_balance(conf, r1_bio); if (rdisk < 0) { /* couldn't find anywhere to read from */ raid_end_bio_io(r1_bio); return 0; } mirror = conf->mirrors + rdisk; r1_bio->read_disk = rdisk; read_bio = bio_clone(bio, GFP_NOIO); r1_bio->bios[rdisk] = read_bio; read_bio->bi_sector = r1_bio->sector + mirror->rdev->data_offset; read_bio->bi_bdev = mirror->rdev->bdev; read_bio->bi_end_io = raid1_end_read_request; read_bio->bi_rw = READ | do_sync; read_bio->bi_private = r1_bio; generic_make_request(read_bio); return 0; } /* * WRITE: */ /* first select target devices under spinlock and * inc refcount on their rdev. Record them by setting * bios[x] to bio */ disks = conf->raid_disks; #if 0 { static int first=1; if (first) printk("First Write sector %llu disks %d\n", (unsigned long long)r1_bio->sector, disks); first = 0; } #endif retry_write: blocked_rdev = NULL; rcu_read_lock(); for (i = 0; i < disks; i++) { mdk_rdev_t *rdev = rcu_dereference(conf->mirrors[i].rdev); if (rdev && unlikely(test_bit(Blocked, &rdev->flags))) { atomic_inc(&rdev->nr_pending); blocked_rdev = rdev; break; } if (rdev && !test_bit(Faulty, &rdev->flags)) { atomic_inc(&rdev->nr_pending); if (test_bit(Faulty, &rdev->flags)) { rdev_dec_pending(rdev, mddev); r1_bio->bios[i] = NULL; } else r1_bio->bios[i] = bio; targets++; } else r1_bio->bios[i] = NULL; } rcu_read_unlock(); if (unlikely(blocked_rdev)) { /* Wait for this device to become unblocked */ int j; for (j = 0; j < i; j++) if (r1_bio->bios[j]) rdev_dec_pending(conf->mirrors[j].rdev, mddev); allow_barrier(conf); md_wait_for_blocked_rdev(blocked_rdev, mddev); wait_barrier(conf); goto retry_write; } BUG_ON(targets == 0); /* we never fail the last device */ if (targets < conf->raid_disks) { /* array is degraded, we will not clear the bitmap * on I/O completion (see raid1_end_write_request) */ set_bit(R1BIO_Degraded, &r1_bio->state); } /* do behind I/O ? */ if (bitmap && atomic_read(&bitmap->behind_writes) < bitmap->max_write_behind && (behind_pages = alloc_behind_pages(bio)) != NULL) set_bit(R1BIO_BehindIO, &r1_bio->state); atomic_set(&r1_bio->remaining, 0); atomic_set(&r1_bio->behind_remaining, 0); do_barriers = bio_barrier(bio); if (do_barriers) set_bit(R1BIO_Barrier, &r1_bio->state); bio_list_init(&bl); for (i = 0; i < disks; i++) { struct bio *mbio; if (!r1_bio->bios[i]) continue; mbio = bio_clone(bio, GFP_NOIO); r1_bio->bios[i] = mbio; mbio->bi_sector = r1_bio->sector + conf->mirrors[i].rdev->data_offset; mbio->bi_bdev = conf->mirrors[i].rdev->bdev; mbio->bi_end_io = raid1_end_write_request; mbio->bi_rw = WRITE | do_barriers | do_sync; mbio->bi_private = r1_bio; if (behind_pages) { struct bio_vec *bvec; int j; /* Yes, I really want the '__' version so that * we clear any unused pointer in the io_vec, rather * than leave them unchanged. This is important * because when we come to free the pages, we won't * know the originial bi_idx, so we just free * them all */ __bio_for_each_segment(bvec, mbio, j, 0) bvec->bv_page = behind_pages[j]; if (test_bit(WriteMostly, &conf->mirrors[i].rdev->flags)) atomic_inc(&r1_bio->behind_remaining); } atomic_inc(&r1_bio->remaining); bio_list_add(&bl, mbio); } kfree(behind_pages); /* the behind pages are attached to the bios now */ bitmap_startwrite(bitmap, bio->bi_sector, r1_bio->sectors, test_bit(R1BIO_BehindIO, &r1_bio->state)); spin_lock_irqsave(&conf->device_lock, flags); bio_list_merge(&conf->pending_bio_list, &bl); bio_list_init(&bl); blk_plug_device(mddev->queue); spin_unlock_irqrestore(&conf->device_lock, flags); /* In case raid1d snuck into freeze_array */ wake_up(&conf->wait_barrier); if (do_sync) md_wakeup_thread(mddev->thread); #if 0 while ((bio = bio_list_pop(&bl)) != NULL) generic_make_request(bio); #endif return 0; } static void status(struct seq_file *seq, mddev_t *mddev) { conf_t *conf = mddev_to_conf(mddev); int i; seq_printf(seq, " [%d/%d] [", conf->raid_disks, conf->raid_disks - mddev->degraded); rcu_read_lock(); for (i = 0; i < conf->raid_disks; i++) { mdk_rdev_t *rdev = rcu_dereference(conf->mirrors[i].rdev); seq_printf(seq, "%s", rdev && test_bit(In_sync, &rdev->flags) ? "U" : "_"); } rcu_read_unlock(); seq_printf(seq, "]"); } static void error(mddev_t *mddev, mdk_rdev_t *rdev) { char b[BDEVNAME_SIZE]; conf_t *conf = mddev_to_conf(mddev); /* * If it is not operational, then we have already marked it as dead * else if it is the last working disks, ignore the error, let the * next level up know. * else mark the drive as failed */ if (test_bit(In_sync, &rdev->flags) && (conf->raid_disks - mddev->degraded) == 1) /* * Don't fail the drive, act as though we were just a * normal single drive */ return; if (test_and_clear_bit(In_sync, &rdev->flags)) { unsigned long flags; spin_lock_irqsave(&conf->device_lock, flags); mddev->degraded++; set_bit(Faulty, &rdev->flags); spin_unlock_irqrestore(&conf->device_lock, flags); /* * if recovery is running, make sure it aborts. */ set_bit(MD_RECOVERY_INTR, &mddev->recovery); } else set_bit(Faulty, &rdev->flags); set_bit(MD_CHANGE_DEVS, &mddev->flags); printk(KERN_ALERT "raid1: Disk failure on %s, disabling device.\n" "raid1: Operation continuing on %d devices.\n", bdevname(rdev->bdev,b), conf->raid_disks - mddev->degraded); } static void print_conf(conf_t *conf) { int i; printk("RAID1 conf printout:\n"); if (!conf) { printk("(!conf)\n"); return; } printk(" --- wd:%d rd:%d\n", conf->raid_disks - conf->mddev->degraded, conf->raid_disks); rcu_read_lock(); for (i = 0; i < conf->raid_disks; i++) { char b[BDEVNAME_SIZE]; mdk_rdev_t *rdev = rcu_dereference(conf->mirrors[i].rdev); if (rdev) printk(" disk %d, wo:%d, o:%d, dev:%s\n", i, !test_bit(In_sync, &rdev->flags), !test_bit(Faulty, &rdev->flags), bdevname(rdev->bdev,b)); } rcu_read_unlock(); } static void close_sync(conf_t *conf) { wait_barrier(conf); allow_barrier(conf); mempool_destroy(conf->r1buf_pool); conf->r1buf_pool = NULL; } static int raid1_spare_active(mddev_t *mddev) { int i; conf_t *conf = mddev->private; /* * Find all failed disks within the RAID1 configuration * and mark them readable. * Called under mddev lock, so rcu protection not needed. */ for (i = 0; i < conf->raid_disks; i++) { mdk_rdev_t *rdev = conf->mirrors[i].rdev; if (rdev && !test_bit(Faulty, &rdev->flags) && !test_and_set_bit(In_sync, &rdev->flags)) { unsigned long flags; spin_lock_irqsave(&conf->device_lock, flags); mddev->degraded--; spin_unlock_irqrestore(&conf->device_lock, flags); } } print_conf(conf); return 0; } static int raid1_add_disk(mddev_t *mddev, mdk_rdev_t *rdev) { conf_t *conf = mddev->private; int err = -EEXIST; int mirror = 0; mirror_info_t *p; int first = 0; int last = mddev->raid_disks - 1; if (rdev->raid_disk >= 0) first = last = rdev->raid_disk; for (mirror = first; mirror <= last; mirror++) if ( !(p=conf->mirrors+mirror)->rdev) { blk_queue_stack_limits(mddev->queue, rdev->bdev->bd_disk->queue); /* as we don't honour merge_bvec_fn, we must never risk * violating it, so limit ->max_sector to one PAGE, as * a one page request is never in violation. */ if (rdev->bdev->bd_disk->queue->merge_bvec_fn && mddev->queue->max_sectors > (PAGE_SIZE>>9)) blk_queue_max_sectors(mddev->queue, PAGE_SIZE>>9); p->head_position = 0; rdev->raid_disk = mirror; err = 0; /* As all devices are equivalent, we don't need a full recovery * if this was recently any drive of the array */ if (rdev->saved_raid_disk < 0) conf->fullsync = 1; rcu_assign_pointer(p->rdev, rdev); break; } print_conf(conf); return err; } static int raid1_remove_disk(mddev_t *mddev, int number) { conf_t *conf = mddev->private; int err = 0; mdk_rdev_t *rdev; mirror_info_t *p = conf->mirrors+ number; print_conf(conf); rdev = p->rdev; if (rdev) { if (test_bit(In_sync, &rdev->flags) || atomic_read(&rdev->nr_pending)) { err = -EBUSY; goto abort; } /* Only remove non-faulty devices is recovery * is not possible. */ if (!test_bit(Faulty, &rdev->flags) && mddev->degraded < conf->raid_disks) { err = -EBUSY; goto abort; } p->rdev = NULL; synchronize_rcu(); if (atomic_read(&rdev->nr_pending)) { /* lost the race, try later */ err = -EBUSY; p->rdev = rdev; } } abort: print_conf(conf); return err; } static void end_sync_read(struct bio *bio, int error) { r1bio_t * r1_bio = (r1bio_t *)(bio->bi_private); int i; for (i=r1_bio->mddev->raid_disks; i--; ) if (r1_bio->bios[i] == bio) break; BUG_ON(i < 0); update_head_pos(i, r1_bio); /* * we have read a block, now it needs to be re-written, * or re-read if the read failed. * We don't do much here, just schedule handling by raid1d */ if (test_bit(BIO_UPTODATE, &bio->bi_flags)) set_bit(R1BIO_Uptodate, &r1_bio->state); if (atomic_dec_and_test(&r1_bio->remaining)) reschedule_retry(r1_bio); } static void end_sync_write(struct bio *bio, int error) { int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags); r1bio_t * r1_bio = (r1bio_t *)(bio->bi_private); mddev_t *mddev = r1_bio->mddev; conf_t *conf = mddev_to_conf(mddev); int i; int mirror=0; for (i = 0; i < conf->raid_disks; i++) if (r1_bio->bios[i] == bio) { mirror = i; break; } if (!uptodate) { int sync_blocks = 0; sector_t s = r1_bio->sector; long sectors_to_go = r1_bio->sectors; /* make sure these bits doesn't get cleared. */ do { bitmap_end_sync(mddev->bitmap, s, &sync_blocks, 1); s += sync_blocks; sectors_to_go -= sync_blocks; } while (sectors_to_go > 0); md_error(mddev, conf->mirrors[mirror].rdev); } update_head_pos(mirror, r1_bio); if (atomic_dec_and_test(&r1_bio->remaining)) { md_done_sync(mddev, r1_bio->sectors, uptodate); put_buf(r1_bio); } } static void sync_request_write(mddev_t *mddev, r1bio_t *r1_bio) { conf_t *conf = mddev_to_conf(mddev); int i; int disks = conf->raid_disks; struct bio *bio, *wbio; bio = r1_bio->bios[r1_bio->read_disk]; if (test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery)) { /* We have read all readable devices. If we haven't * got the block, then there is no hope left. * If we have, then we want to do a comparison * and skip the write if everything is the same. * If any blocks failed to read, then we need to * attempt an over-write */ int primary; if (!test_bit(R1BIO_Uptodate, &r1_bio->state)) { for (i=0; i<mddev->raid_disks; i++) if (r1_bio->bios[i]->bi_end_io == end_sync_read) md_error(mddev, conf->mirrors[i].rdev); md_done_sync(mddev, r1_bio->sectors, 1); put_buf(r1_bio); return; } for (primary=0; primary<mddev->raid_disks; primary++) if (r1_bio->bios[primary]->bi_end_io == end_sync_read && test_bit(BIO_UPTODATE, &r1_bio->bios[primary]->bi_flags)) { r1_bio->bios[primary]->bi_end_io = NULL; rdev_dec_pending(conf->mirrors[primary].rdev, mddev); break; } r1_bio->read_disk = primary; for (i=0; i<mddev->raid_disks; i++) if (r1_bio->bios[i]->bi_end_io == end_sync_read) { int j; int vcnt = r1_bio->sectors >> (PAGE_SHIFT- 9); struct bio *pbio = r1_bio->bios[primary]; struct bio *sbio = r1_bio->bios[i]; if (test_bit(BIO_UPTODATE, &sbio->bi_flags)) { for (j = vcnt; j-- ; ) { struct page *p, *s; p = pbio->bi_io_vec[j].bv_page; s = sbio->bi_io_vec[j].bv_page; if (memcmp(page_address(p), page_address(s), PAGE_SIZE)) break; } } else j = 0; if (j >= 0) mddev->resync_mismatches += r1_bio->sectors; if (j < 0 || (test_bit(MD_RECOVERY_CHECK, &mddev->recovery) && test_bit(BIO_UPTODATE, &sbio->bi_flags))) { sbio->bi_end_io = NULL; rdev_dec_pending(conf->mirrors[i].rdev, mddev); } else { /* fixup the bio for reuse */ int size; sbio->bi_vcnt = vcnt; sbio->bi_size = r1_bio->sectors << 9; sbio->bi_idx = 0; sbio->bi_phys_segments = 0; sbio->bi_hw_segments = 0; sbio->bi_hw_front_size = 0; sbio->bi_hw_back_size = 0; sbio->bi_flags &= ~(BIO_POOL_MASK - 1); sbio->bi_flags |= 1 << BIO_UPTODATE; sbio->bi_next = NULL; sbio->bi_sector = r1_bio->sector + conf->mirrors[i].rdev->data_offset; sbio->bi_bdev = conf->mirrors[i].rdev->bdev; size = sbio->bi_size; for (j = 0; j < vcnt ; j++) { struct bio_vec *bi; bi = &sbio->bi_io_vec[j]; bi->bv_offset = 0; if (size > PAGE_SIZE) bi->bv_len = PAGE_SIZE; else bi->bv_len = size; size -= PAGE_SIZE; memcpy(page_address(bi->bv_page), page_address(pbio->bi_io_vec[j].bv_page), PAGE_SIZE); } } } } if (!test_bit(R1BIO_Uptodate, &r1_bio->state)) { /* ouch - failed to read all of that. * Try some synchronous reads of other devices to get * good data, much like with normal read errors. Only * read into the pages we already have so we don't * need to re-issue the read request. * We don't need to freeze the array, because being in an * active sync request, there is no normal IO, and * no overlapping syncs. */ sector_t sect = r1_bio->sector; int sectors = r1_bio->sectors; int idx = 0; while(sectors) { int s = sectors; int d = r1_bio->read_disk; int success = 0; mdk_rdev_t *rdev; if (s > (PAGE_SIZE>>9)) s = PAGE_SIZE >> 9; do { if (r1_bio->bios[d]->bi_end_io == end_sync_read) { /* No rcu protection needed here devices * can only be removed when no resync is * active, and resync is currently active */ rdev = conf->mirrors[d].rdev; if (sync_page_io(rdev->bdev, sect + rdev->data_offset, s<<9, bio->bi_io_vec[idx].bv_page, READ)) { success = 1; break; } } d++; if (d == conf->raid_disks) d = 0; } while (!success && d != r1_bio->read_disk); if (success) { int start = d; /* write it back and re-read */ set_bit(R1BIO_Uptodate, &r1_bio->state); while (d != r1_bio->read_disk) { if (d == 0) d = conf->raid_disks; d--; if (r1_bio->bios[d]->bi_end_io != end_sync_read) continue; rdev = conf->mirrors[d].rdev; atomic_add(s, &rdev->corrected_errors); if (sync_page_io(rdev->bdev, sect + rdev->data_offset, s<<9, bio->bi_io_vec[idx].bv_page, WRITE) == 0) md_error(mddev, rdev); } d = start; while (d != r1_bio->read_disk) { if (d == 0) d = conf->raid_disks; d--; if (r1_bio->bios[d]->bi_end_io != end_sync_read) continue; rdev = conf->mirrors[d].rdev; if (sync_page_io(rdev->bdev, sect + rdev->data_offset, s<<9, bio->bi_io_vec[idx].bv_page, READ) == 0) md_error(mddev, rdev); } } else { char b[BDEVNAME_SIZE]; /* Cannot read from anywhere, array is toast */ md_error(mddev, conf->mirrors[r1_bio->read_disk].rdev); printk(KERN_ALERT "raid1: %s: unrecoverable I/O read error" " for block %llu\n", bdevname(bio->bi_bdev,b), (unsigned long long)r1_bio->sector); md_done_sync(mddev, r1_bio->sectors, 0); put_buf(r1_bio); return; } sectors -= s; sect += s; idx ++; } } /* * schedule writes */ atomic_set(&r1_bio->remaining, 1); for (i = 0; i < disks ; i++) { wbio = r1_bio->bios[i]; if (wbio->bi_end_io == NULL || (wbio->bi_end_io == end_sync_read && (i == r1_bio->read_disk || !test_bit(MD_RECOVERY_SYNC, &mddev->recovery)))) continue; wbio->bi_rw = WRITE; wbio->bi_end_io = end_sync_write; atomic_inc(&r1_bio->remaining); md_sync_acct(conf->mirrors[i].rdev->bdev, wbio->bi_size >> 9); generic_make_request(wbio); } if (atomic_dec_and_test(&r1_bio->remaining)) { /* if we're here, all write(s) have completed, so clean up */ md_done_sync(mddev, r1_bio->sectors, 1); put_buf(r1_bio); } } /* * This is a kernel thread which: * * 1. Retries failed read operations on working mirrors. * 2. Updates the raid superblock when problems encounter. * 3. Performs writes following reads for array syncronising. */ static void fix_read_error(conf_t *conf, int read_disk, sector_t sect, int sectors) { mddev_t *mddev = conf->mddev; while(sectors) { int s = sectors; int d = read_disk; int success = 0; int start; mdk_rdev_t *rdev; if (s > (PAGE_SIZE>>9)) s = PAGE_SIZE >> 9; do { /* Note: no rcu protection needed here * as this is synchronous in the raid1d thread * which is the thread that might remove * a device. If raid1d ever becomes multi-threaded.... */ rdev = conf->mirrors[d].rdev; if (rdev && test_bit(In_sync, &rdev->flags) && sync_page_io(rdev->bdev, sect + rdev->data_offset, s<<9, conf->tmppage, READ)) success = 1; else { d++; if (d == conf->raid_disks) d = 0; } } while (!success && d != read_disk); if (!success) { /* Cannot read from anywhere -- bye bye array */ md_error(mddev, conf->mirrors[read_disk].rdev); break; } /* write it back and re-read */ start = d; while (d != read_disk) { if (d==0) d = conf->raid_disks; d--; rdev = conf->mirrors[d].rdev; if (rdev && test_bit(In_sync, &rdev->flags)) { if (sync_page_io(rdev->bdev, sect + rdev->data_offset, s<<9, conf->tmppage, WRITE) == 0) /* Well, this device is dead */ md_error(mddev, rdev); } } d = start; while (d != read_disk) { char b[BDEVNAME_SIZE]; if (d==0) d = conf->raid_disks; d--; rdev = conf->mirrors[d].rdev; if (rdev && test_bit(In_sync, &rdev->flags)) { if (sync_page_io(rdev->bdev, sect + rdev->data_offset, s<<9, conf->tmppage, READ) == 0) /* Well, this device is dead */ md_error(mddev, rdev); else { atomic_add(s, &rdev->corrected_errors); printk(KERN_INFO "raid1:%s: read error corrected " "(%d sectors at %llu on %s)\n", mdname(mddev), s, (unsigned long long)(sect + rdev->data_offset), bdevname(rdev->bdev, b)); } } } sectors -= s; sect += s; } } static void raid1d(mddev_t *mddev) { r1bio_t *r1_bio; struct bio *bio; unsigned long flags; conf_t *conf = mddev_to_conf(mddev); struct list_head *head = &conf->retry_list; int unplug=0; mdk_rdev_t *rdev; md_check_recovery(mddev); for (;;) { char b[BDEVNAME_SIZE]; unplug += flush_pending_writes(conf); spin_lock_irqsave(&conf->device_lock, flags); if (list_empty(head)) { spin_unlock_irqrestore(&conf->device_lock, flags); break; } r1_bio = list_entry(head->prev, r1bio_t, retry_list); list_del(head->prev); conf->nr_queued--; spin_unlock_irqrestore(&conf->device_lock, flags); mddev = r1_bio->mddev; conf = mddev_to_conf(mddev); if (test_bit(R1BIO_IsSync, &r1_bio->state)) { sync_request_write(mddev, r1_bio); unplug = 1; } else if (test_bit(R1BIO_BarrierRetry, &r1_bio->state)) { /* some requests in the r1bio were BIO_RW_BARRIER * requests which failed with -EOPNOTSUPP. Hohumm.. * Better resubmit without the barrier. * We know which devices to resubmit for, because * all others have had their bios[] entry cleared. * We already have a nr_pending reference on these rdevs. */ int i; const int do_sync = bio_sync(r1_bio->master_bio); clear_bit(R1BIO_BarrierRetry, &r1_bio->state); clear_bit(R1BIO_Barrier, &r1_bio->state); for (i=0; i < conf->raid_disks; i++) if (r1_bio->bios[i]) atomic_inc(&r1_bio->remaining); for (i=0; i < conf->raid_disks; i++) if (r1_bio->bios[i]) { struct bio_vec *bvec; int j; bio = bio_clone(r1_bio->master_bio, GFP_NOIO); /* copy pages from the failed bio, as * this might be a write-behind device */ __bio_for_each_segment(bvec, bio, j, 0) bvec->bv_page = bio_iovec_idx(r1_bio->bios[i], j)->bv_page; bio_put(r1_bio->bios[i]); bio->bi_sector = r1_bio->sector + conf->mirrors[i].rdev->data_offset; bio->bi_bdev = conf->mirrors[i].rdev->bdev; bio->bi_end_io = raid1_end_write_request; bio->bi_rw = WRITE | do_sync; bio->bi_private = r1_bio; r1_bio->bios[i] = bio; generic_make_request(bio); } } else { int disk; /* we got a read error. Maybe the drive is bad. Maybe just * the block and we can fix it. * We freeze all other IO, and try reading the block from * other devices. When we find one, we re-write * and check it that fixes the read error. * This is all done synchronously while the array is * frozen */ if (mddev->ro == 0) { freeze_array(conf); fix_read_error(conf, r1_bio->read_disk, r1_bio->sector, r1_bio->sectors); unfreeze_array(conf); } bio = r1_bio->bios[r1_bio->read_disk]; if ((disk=read_balance(conf, r1_bio)) == -1) { printk(KERN_ALERT "raid1: %s: unrecoverable I/O" " read error for block %llu\n", bdevname(bio->bi_bdev,b), (unsigned long long)r1_bio->sector); raid_end_bio_io(r1_bio); } else { const int do_sync = bio_sync(r1_bio->master_bio); r1_bio->bios[r1_bio->read_disk] = mddev->ro ? IO_BLOCKED : NULL; r1_bio->read_disk = disk; bio_put(bio); bio = bio_clone(r1_bio->master_bio, GFP_NOIO); r1_bio->bios[r1_bio->read_disk] = bio; rdev = conf->mirrors[disk].rdev; if (printk_ratelimit()) printk(KERN_ERR "raid1: %s: redirecting sector %llu to" " another mirror\n", bdevname(rdev->bdev,b), (unsigned long long)r1_bio->sector); bio->bi_sector = r1_bio->sector + rdev->data_offset; bio->bi_bdev = rdev->bdev; bio->bi_end_io = raid1_end_read_request; bio->bi_rw = READ | do_sync; bio->bi_private = r1_bio; unplug = 1; generic_make_request(bio); } } } if (unplug) unplug_slaves(mddev); } static int init_resync(conf_t *conf) { int buffs; buffs = RESYNC_WINDOW / RESYNC_BLOCK_SIZE; BUG_ON(conf->r1buf_pool); conf->r1buf_pool = mempool_create(buffs, r1buf_pool_alloc, r1buf_pool_free, conf->poolinfo); if (!conf->r1buf_pool) return -ENOMEM; conf->next_resync = 0; return 0; } /* * perform a "sync" on one "block" * * We need to make sure that no normal I/O request - particularly write * requests - conflict with active sync requests. * * This is achieved by tracking pending requests and a 'barrier' concept * that can be installed to exclude normal IO requests. */ static sector_t sync_request(mddev_t *mddev, sector_t sector_nr, int *skipped, int go_faster) { conf_t *conf = mddev_to_conf(mddev); r1bio_t *r1_bio; struct bio *bio; sector_t max_sector, nr_sectors; int disk = -1; int i; int wonly = -1; int write_targets = 0, read_targets = 0; int sync_blocks; int still_degraded = 0; if (!conf->r1buf_pool) { /* printk("sync start - bitmap %p\n", mddev->bitmap); */ if (init_resync(conf)) return 0; } max_sector = mddev->size << 1; if (sector_nr >= max_sector) { /* If we aborted, we need to abort the * sync on the 'current' bitmap chunk (there will * only be one in raid1 resync. * We can find the current addess in mddev->curr_resync */ if (mddev->curr_resync < max_sector) /* aborted */ bitmap_end_sync(mddev->bitmap, mddev->curr_resync, &sync_blocks, 1); else /* completed sync */ conf->fullsync = 0; bitmap_close_sync(mddev->bitmap); close_sync(conf); return 0; } if (mddev->bitmap == NULL && mddev->recovery_cp == MaxSector && !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery) && conf->fullsync == 0) { *skipped = 1; return max_sector - sector_nr; } /* before building a request, check if we can skip these blocks.. * This call the bitmap_start_sync doesn't actually record anything */ if (!bitmap_start_sync(mddev->bitmap, sector_nr, &sync_blocks, 1) && !conf->fullsync && !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery)) { /* We can skip this block, and probably several more */ *skipped = 1; return sync_blocks; } /* * If there is non-resync activity waiting for a turn, * and resync is going fast enough, * then let it though before starting on this new sync request. */ if (!go_faster && conf->nr_waiting) msleep_interruptible(1000); bitmap_cond_end_sync(mddev->bitmap, sector_nr); raise_barrier(conf); conf->next_resync = sector_nr; r1_bio = mempool_alloc(conf->r1buf_pool, GFP_NOIO); rcu_read_lock(); /* * If we get a correctably read error during resync or recovery, * we might want to read from a different device. So we * flag all drives that could conceivably be read from for READ, * and any others (which will be non-In_sync devices) for WRITE. * If a read fails, we try reading from something else for which READ * is OK. */ r1_bio->mddev = mddev; r1_bio->sector = sector_nr; r1_bio->state = 0; set_bit(R1BIO_IsSync, &r1_bio->state); for (i=0; i < conf->raid_disks; i++) { mdk_rdev_t *rdev; bio = r1_bio->bios[i]; /* take from bio_init */ bio->bi_next = NULL; bio->bi_flags |= 1 << BIO_UPTODATE; bio->bi_rw = READ; bio->bi_vcnt = 0; bio->bi_idx = 0; bio->bi_phys_segments = 0; bio->bi_hw_segments = 0; bio->bi_size = 0; bio->bi_end_io = NULL; bio->bi_private = NULL; rdev = rcu_dereference(conf->mirrors[i].rdev); if (rdev == NULL || test_bit(Faulty, &rdev->flags)) { still_degraded = 1; continue; } else if (!test_bit(In_sync, &rdev->flags)) { bio->bi_rw = WRITE; bio->bi_end_io = end_sync_write; write_targets ++; } else { /* may need to read from here */ bio->bi_rw = READ; bio->bi_end_io = end_sync_read; if (test_bit(WriteMostly, &rdev->flags)) { if (wonly < 0) wonly = i; } else { if (disk < 0) disk = i; } read_targets++; } atomic_inc(&rdev->nr_pending); bio->bi_sector = sector_nr + rdev->data_offset; bio->bi_bdev = rdev->bdev; bio->bi_private = r1_bio; } rcu_read_unlock(); if (disk < 0) disk = wonly; r1_bio->read_disk = disk; if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery) && read_targets > 0) /* extra read targets are also write targets */ write_targets += read_targets-1; if (write_targets == 0 || read_targets == 0) { /* There is nowhere to write, so all non-sync * drives must be failed - so we are finished */ sector_t rv = max_sector - sector_nr; *skipped = 1; put_buf(r1_bio); return rv; } if (max_sector > mddev->resync_max) max_sector = mddev->resync_max; /* Don't do IO beyond here */ nr_sectors = 0; sync_blocks = 0; do { struct page *page; int len = PAGE_SIZE; if (sector_nr + (len>>9) > max_sector) len = (max_sector - sector_nr) << 9; if (len == 0) break; if (sync_blocks == 0) { if (!bitmap_start_sync(mddev->bitmap, sector_nr, &sync_blocks, still_degraded) && !conf->fullsync && !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery)) break; BUG_ON(sync_blocks < (PAGE_SIZE>>9)); if (len > (sync_blocks<<9)) len = sync_blocks<<9; } for (i=0 ; i < conf->raid_disks; i++) { bio = r1_bio->bios[i]; if (bio->bi_end_io) { page = bio->bi_io_vec[bio->bi_vcnt].bv_page; if (bio_add_page(bio, page, len, 0) == 0) { /* stop here */ bio->bi_io_vec[bio->bi_vcnt].bv_page = page; while (i > 0) { i--; bio = r1_bio->bios[i]; if (bio->bi_end_io==NULL) continue; /* remove last page from this bio */ bio->bi_vcnt--; bio->bi_size -= len; bio->bi_flags &= ~(1<< BIO_SEG_VALID); } goto bio_full; } } } nr_sectors += len>>9; sector_nr += len>>9; sync_blocks -= (len>>9); } while (r1_bio->bios[disk]->bi_vcnt < RESYNC_PAGES); bio_full: r1_bio->sectors = nr_sectors; /* For a user-requested sync, we read all readable devices and do a * compare */ if (test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery)) { atomic_set(&r1_bio->remaining, read_targets); for (i=0; i<conf->raid_disks; i++) { bio = r1_bio->bios[i]; if (bio->bi_end_io == end_sync_read) { md_sync_acct(bio->bi_bdev, nr_sectors); generic_make_request(bio); } } } else { atomic_set(&r1_bio->remaining, 1); bio = r1_bio->bios[r1_bio->read_disk]; md_sync_acct(bio->bi_bdev, nr_sectors); generic_make_request(bio); } return nr_sectors; } static int run(mddev_t *mddev) { conf_t *conf; int i, j, disk_idx; mirror_info_t *disk; mdk_rdev_t *rdev; struct list_head *tmp; if (mddev->level != 1) { printk("raid1: %s: raid level not set to mirroring (%d)\n", mdname(mddev), mddev->level); goto out; } if (mddev->reshape_position != MaxSector) { printk("raid1: %s: reshape_position set but not supported\n", mdname(mddev)); goto out; } /* * copy the already verified devices into our private RAID1 * bookkeeping area. [whatever we allocate in run(), * should be freed in stop()] */ conf = kzalloc(sizeof(conf_t), GFP_KERNEL); mddev->private = conf; if (!conf) goto out_no_mem; conf->mirrors = kzalloc(sizeof(struct mirror_info)*mddev->raid_disks, GFP_KERNEL); if (!conf->mirrors) goto out_no_mem; conf->tmppage = alloc_page(GFP_KERNEL); if (!conf->tmppage) goto out_no_mem; conf->poolinfo = kmalloc(sizeof(*conf->poolinfo), GFP_KERNEL); if (!conf->poolinfo) goto out_no_mem; conf->poolinfo->mddev = mddev; conf->poolinfo->raid_disks = mddev->raid_disks; conf->r1bio_pool = mempool_create(NR_RAID1_BIOS, r1bio_pool_alloc, r1bio_pool_free, conf->poolinfo); if (!conf->r1bio_pool) goto out_no_mem; spin_lock_init(&conf->device_lock); mddev->queue->queue_lock = &conf->device_lock; rdev_for_each(rdev, tmp, mddev) { disk_idx = rdev->raid_disk; if (disk_idx >= mddev->raid_disks || disk_idx < 0) continue; disk = conf->mirrors + disk_idx; disk->rdev = rdev; blk_queue_stack_limits(mddev->queue, rdev->bdev->bd_disk->queue); /* as we don't honour merge_bvec_fn, we must never risk * violating it, so limit ->max_sector to one PAGE, as * a one page request is never in violation. */ if (rdev->bdev->bd_disk->queue->merge_bvec_fn && mddev->queue->max_sectors > (PAGE_SIZE>>9)) blk_queue_max_sectors(mddev->queue, PAGE_SIZE>>9); disk->head_position = 0; } conf->raid_disks = mddev->raid_disks; conf->mddev = mddev; INIT_LIST_HEAD(&conf->retry_list); spin_lock_init(&conf->resync_lock); init_waitqueue_head(&conf->wait_barrier); bio_list_init(&conf->pending_bio_list); bio_list_init(&conf->flushing_bio_list); mddev->degraded = 0; for (i = 0; i < conf->raid_disks; i++) { disk = conf->mirrors + i; if (!disk->rdev || !test_bit(In_sync, &disk->rdev->flags)) { disk->head_position = 0; mddev->degraded++; if (disk->rdev) conf->fullsync = 1; } } if (mddev->degraded == conf->raid_disks) { printk(KERN_ERR "raid1: no operational mirrors for %s\n", mdname(mddev)); goto out_free_conf; } if (conf->raid_disks - mddev->degraded == 1) mddev->recovery_cp = MaxSector; /* * find the first working one and use it as a starting point * to read balancing. */ for (j = 0; j < conf->raid_disks && (!conf->mirrors[j].rdev || !test_bit(In_sync, &conf->mirrors[j].rdev->flags)) ; j++) /* nothing */; conf->last_used = j; mddev->thread = md_register_thread(raid1d, mddev, "%s_raid1"); if (!mddev->thread) { printk(KERN_ERR "raid1: couldn't allocate thread for %s\n", mdname(mddev)); goto out_free_conf; } printk(KERN_INFO "raid1: raid set %s active with %d out of %d mirrors\n", mdname(mddev), mddev->raid_disks - mddev->degraded, mddev->raid_disks); /* * Ok, everything is just fine now */ mddev->array_sectors = mddev->size * 2; mddev->queue->unplug_fn = raid1_unplug; mddev->queue->backing_dev_info.congested_fn = raid1_congested; mddev->queue->backing_dev_info.congested_data = mddev; return 0; out_no_mem: printk(KERN_ERR "raid1: couldn't allocate memory for %s\n", mdname(mddev)); out_free_conf: if (conf) { if (conf->r1bio_pool) mempool_destroy(conf->r1bio_pool); kfree(conf->mirrors); safe_put_page(conf->tmppage); kfree(conf->poolinfo); kfree(conf); mddev->private = NULL; } out: return -EIO; } static int stop(mddev_t *mddev) { conf_t *conf = mddev_to_conf(mddev); struct bitmap *bitmap = mddev->bitmap; int behind_wait = 0; /* wait for behind writes to complete */ while (bitmap && atomic_read(&bitmap->behind_writes) > 0) { behind_wait++; printk(KERN_INFO "raid1: behind writes in progress on device %s, waiting to stop (%d)\n", mdname(mddev), behind_wait); set_current_state(TASK_UNINTERRUPTIBLE); schedule_timeout(HZ); /* wait a second */ /* need to kick something here to make sure I/O goes? */ } md_unregister_thread(mddev->thread); mddev->thread = NULL; blk_sync_queue(mddev->queue); /* the unplug fn references 'conf'*/ if (conf->r1bio_pool) mempool_destroy(conf->r1bio_pool); kfree(conf->mirrors); kfree(conf->poolinfo); kfree(conf); mddev->private = NULL; return 0; } static int raid1_resize(mddev_t *mddev, sector_t sectors) { /* no resync is happening, and there is enough space * on all devices, so we can resize. * We need to make sure resync covers any new space. * If the array is shrinking we should possibly wait until * any io in the removed space completes, but it hardly seems * worth it. */ mddev->array_sectors = sectors; set_capacity(mddev->gendisk, mddev->array_sectors); mddev->changed = 1; if (mddev->array_sectors / 2 > mddev->size && mddev->recovery_cp == MaxSector) { mddev->recovery_cp = mddev->size << 1; set_bit(MD_RECOVERY_NEEDED, &mddev->recovery); } mddev->size = mddev->array_sectors / 2; mddev->resync_max_sectors = sectors; return 0; } static int raid1_reshape(mddev_t *mddev) { /* We need to: * 1/ resize the r1bio_pool * 2/ resize conf->mirrors * * We allocate a new r1bio_pool if we can. * Then raise a device barrier and wait until all IO stops. * Then resize conf->mirrors and swap in the new r1bio pool. * * At the same time, we "pack" the devices so that all the missing * devices have the higher raid_disk numbers. */ mempool_t *newpool, *oldpool; struct pool_info *newpoolinfo; mirror_info_t *newmirrors; conf_t *conf = mddev_to_conf(mddev); int cnt, raid_disks; unsigned long flags; int d, d2, err; /* Cannot change chunk_size, layout, or level */ if (mddev->chunk_size != mddev->new_chunk || mddev->layout != mddev->new_layout || mddev->level != mddev->new_level) { mddev->new_chunk = mddev->chunk_size; mddev->new_layout = mddev->layout; mddev->new_level = mddev->level; return -EINVAL; } err = md_allow_write(mddev); if (err) return err; raid_disks = mddev->raid_disks + mddev->delta_disks; if (raid_disks < conf->raid_disks) { cnt=0; for (d= 0; d < conf->raid_disks; d++) if (conf->mirrors[d].rdev) cnt++; if (cnt > raid_disks) return -EBUSY; } newpoolinfo = kmalloc(sizeof(*newpoolinfo), GFP_KERNEL); if (!newpoolinfo) return -ENOMEM; newpoolinfo->mddev = mddev; newpoolinfo->raid_disks = raid_disks; newpool = mempool_create(NR_RAID1_BIOS, r1bio_pool_alloc, r1bio_pool_free, newpoolinfo); if (!newpool) { kfree(newpoolinfo); return -ENOMEM; } newmirrors = kzalloc(sizeof(struct mirror_info) * raid_disks, GFP_KERNEL); if (!newmirrors) { kfree(newpoolinfo); mempool_destroy(newpool); return -ENOMEM; } raise_barrier(conf); /* ok, everything is stopped */ oldpool = conf->r1bio_pool; conf->r1bio_pool = newpool; for (d = d2 = 0; d < conf->raid_disks; d++) { mdk_rdev_t *rdev = conf->mirrors[d].rdev; if (rdev && rdev->raid_disk != d2) { char nm[20]; sprintf(nm, "rd%d", rdev->raid_disk); sysfs_remove_link(&mddev->kobj, nm); rdev->raid_disk = d2; sprintf(nm, "rd%d", rdev->raid_disk); sysfs_remove_link(&mddev->kobj, nm); if (sysfs_create_link(&mddev->kobj, &rdev->kobj, nm)) printk(KERN_WARNING "md/raid1: cannot register " "%s for %s\n", nm, mdname(mddev)); } if (rdev) newmirrors[d2++].rdev = rdev; } kfree(conf->mirrors); conf->mirrors = newmirrors; kfree(conf->poolinfo); conf->poolinfo = newpoolinfo; spin_lock_irqsave(&conf->device_lock, flags); mddev->degraded += (raid_disks - conf->raid_disks); spin_unlock_irqrestore(&conf->device_lock, flags); conf->raid_disks = mddev->raid_disks = raid_disks; mddev->delta_disks = 0; conf->last_used = 0; /* just make sure it is in-range */ lower_barrier(conf); set_bit(MD_RECOVERY_NEEDED, &mddev->recovery); md_wakeup_thread(mddev->thread); mempool_destroy(oldpool); return 0; } static void raid1_quiesce(mddev_t *mddev, int state) { conf_t *conf = mddev_to_conf(mddev); switch(state) { case 1: raise_barrier(conf); break; case 0: lower_barrier(conf); break; } } static struct mdk_personality raid1_personality = { .name = "raid1", .level = 1, .owner = THIS_MODULE, .make_request = make_request, .run = run, .stop = stop, .status = status, .error_handler = error, .hot_add_disk = raid1_add_disk, .hot_remove_disk= raid1_remove_disk, .spare_active = raid1_spare_active, .sync_request = sync_request, .resize = raid1_resize, .check_reshape = raid1_reshape, .quiesce = raid1_quiesce, }; static int __init raid_init(void) { return register_md_personality(&raid1_personality); } static void raid_exit(void) { unregister_md_personality(&raid1_personality); } module_init(raid_init); module_exit(raid_exit); MODULE_LICENSE("GPL"); MODULE_ALIAS("md-personality-3"); /* RAID1 */ MODULE_ALIAS("md-raid1"); MODULE_ALIAS("md-level-1");