/* * multipath.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 * * MULTIPATH management functions. * * derived from raid1.c. * * 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/module.h>#include <linux/slab.h>#include <linux/spinlock.h>#include <linux/raid/multipath.h>#include <linux/buffer_head.h>#include <asm/atomic.h> #define MAJOR_NR MD_MAJOR#define MD_DRIVER#define MD_PERSONALITY #define MAX_WORK_PER_DISK 128 #define NR_RESERVED_BUFS 32 static int multipath_map (multipath_conf_t *conf){ int i, disks = conf->raid_disks; /* * Later we do read balancing on the read side * now we use the first available disk. */ rcu_read_lock(); for (i = 0; i < disks; i++) { mdk_rdev_t *rdev = rcu_dereference(conf->multipaths[i].rdev); if (rdev && test_bit(In_sync, &rdev->flags)) { atomic_inc(&rdev->nr_pending); rcu_read_unlock(); return i; } } rcu_read_unlock(); printk(KERN_ERR "multipath_map(): no more operational IO paths?\n"); return (-1);} static void multipath_reschedule_retry (struct multipath_bh *mp_bh){ unsigned long flags; mddev_t *mddev = mp_bh->mddev; multipath_conf_t *conf = mddev_to_conf(mddev); spin_lock_irqsave(&conf->device_lock, flags); list_add(&mp_bh->retry_list, &conf->retry_list); spin_unlock_irqrestore(&conf->device_lock, flags); md_wakeup_thread(mddev->thread);} /* * multipath_end_bh_io() is called when we have finished servicing a multipathed * operation and are ready to return a success/failure code to the buffer * cache layer. */static void multipath_end_bh_io (struct multipath_bh *mp_bh, int err){ struct bio *bio = mp_bh->master_bio; multipath_conf_t *conf = mddev_to_conf(mp_bh->mddev); bio_endio(bio, bio->bi_size, err); mempool_free(mp_bh, conf->pool);} static int multipath_end_request(struct bio *bio, unsigned int bytes_done, int error){ int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags); struct multipath_bh * mp_bh = (struct multipath_bh *)(bio->bi_private); multipath_conf_t *conf = mddev_to_conf(mp_bh->mddev); mdk_rdev_t *rdev = conf->multipaths[mp_bh->path].rdev; if (bio->bi_size) return 1; if (uptodate) multipath_end_bh_io(mp_bh, 0); else if (!bio_rw_ahead(bio)) { /* * oops, IO error: */ char b[BDEVNAME_SIZE]; md_error (mp_bh->mddev, rdev); printk(KERN_ERR "multipath: %s: rescheduling sector %llu\n", bdevname(rdev->bdev,b), (unsigned long long)bio->bi_sector); multipath_reschedule_retry(mp_bh); } else multipath_end_bh_io(mp_bh, error); rdev_dec_pending(rdev, conf->mddev); return 0;} static void unplug_slaves(mddev_t *mddev){ multipath_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->multipaths[i].rdev); if (rdev && !test_bit(Faulty, &rdev->flags) && atomic_read(&rdev->nr_pending)) { request_queue_t *r_queue = bdev_get_queue(rdev->bdev); atomic_inc(&rdev->nr_pending); rcu_read_unlock(); if (r_queue->unplug_fn) r_queue->unplug_fn(r_queue); rdev_dec_pending(rdev, mddev); rcu_read_lock(); } } rcu_read_unlock();} static void multipath_unplug(request_queue_t *q){ unplug_slaves(q->queuedata);} static int multipath_make_request (request_queue_t *q, struct bio * bio){ mddev_t *mddev = q->queuedata; multipath_conf_t *conf = mddev_to_conf(mddev); struct multipath_bh * mp_bh; struct multipath_info *multipath; const int rw = bio_data_dir(bio); if (unlikely(bio_barrier(bio))) { bio_endio(bio, bio->bi_size, -EOPNOTSUPP); return 0; } mp_bh = mempool_alloc(conf->pool, GFP_NOIO); mp_bh->master_bio = bio; mp_bh->mddev = mddev; disk_stat_inc(mddev->gendisk, ios[rw]); disk_stat_add(mddev->gendisk, sectors[rw], bio_sectors(bio)); mp_bh->path = multipath_map(conf); if (mp_bh->path < 0) { bio_endio(bio, bio->bi_size, -EIO); mempool_free(mp_bh, conf->pool); return 0; } multipath = conf->multipaths + mp_bh->path; mp_bh->bio = *bio; mp_bh->bio.bi_sector += multipath->rdev->data_offset; mp_bh->bio.bi_bdev = multipath->rdev->bdev; mp_bh->bio.bi_rw |= (1 << BIO_RW_FAILFAST); mp_bh->bio.bi_end_io = multipath_end_request; mp_bh->bio.bi_private = mp_bh; generic_make_request(&mp_bh->bio); return 0;} static void multipath_status (struct seq_file *seq, mddev_t *mddev){ multipath_conf_t *conf = mddev_to_conf(mddev); int i; seq_printf (seq, " [%d/%d] [", conf->raid_disks, conf->working_disks); for (i = 0; i < conf->raid_disks; i++) seq_printf (seq, "%s", conf->multipaths[i].rdev && test_bit(In_sync, &conf->multipaths[i].rdev->flags) ? "U" : "_"); seq_printf (seq, "]");} static int multipath_issue_flush(request_queue_t *q, struct gendisk *disk, sector_t *error_sector){ mddev_t *mddev = q->queuedata; multipath_conf_t *conf = mddev_to_conf(mddev); int i, ret = 0; rcu_read_lock(); for (i=0; i<mddev->raid_disks && ret == 0; i++) { mdk_rdev_t *rdev = rcu_dereference(conf->multipaths[i].rdev); if (rdev && !test_bit(Faulty, &rdev->flags)) { struct block_device *bdev = rdev->bdev; request_queue_t *r_queue = bdev_get_queue(bdev); if (!r_queue->issue_flush_fn) ret = -EOPNOTSUPP; else { atomic_inc(&rdev->nr_pending); rcu_read_unlock(); ret = r_queue->issue_flush_fn(r_queue, bdev->bd_disk, error_sector); rdev_dec_pending(rdev, mddev); rcu_read_lock(); } } } rcu_read_unlock(); return ret;}static int multipath_congested(void *data, int bits){ mddev_t *mddev = data; multipath_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->multipaths[i].rdev); if (rdev && !test_bit(Faulty, &rdev->flags)) { request_queue_t *q = bdev_get_queue(rdev->bdev); ret |= bdi_congested(&q->backing_dev_info, bits); /* Just like multipath_map, we just check the * first available device */ break; } } rcu_read_unlock(); return ret;} /* * Careful, this can execute in IRQ contexts as well! */static void multipath_error (mddev_t *mddev, mdk_rdev_t *rdev){ multipath_conf_t *conf = mddev_to_conf(mddev); if (conf->working_disks <= 1) { /* * Uh oh, we can do nothing if this is our last path, but * first check if this is a queued request for a device * which has just failed. */ printk(KERN_ALERT "multipath: only one IO path left and IO error.\n"); /* leave it active... it's all we have */ } else { /* * Mark disk as unusable */ if (!test_bit(Faulty, &rdev->flags)) { char b[BDEVNAME_SIZE]; clear_bit(In_sync, &rdev->flags); set_bit(Faulty, &rdev->flags); set_bit(MD_CHANGE_DEVS, &mddev->flags); conf->working_disks--; mddev->degraded++; printk(KERN_ALERT "multipath: IO failure on %s," " disabling IO path. \n Operation continuing" " on %d IO paths.\n", bdevname (rdev->bdev,b), conf->working_disks); } }} static void print_multipath_conf (multipath_conf_t *conf){ int i; struct multipath_info *tmp; printk("MULTIPATH conf printout:\n"); if (!conf) { printk("(conf==NULL)\n"); return; } printk(" --- wd:%d rd:%d\n", conf->working_disks, conf->raid_disks); for (i = 0; i < conf->raid_disks; i++) { char b[BDEVNAME_SIZE]; tmp = conf->multipaths + i; if (tmp->rdev) printk(" disk%d, o:%d, dev:%s\n", i,!test_bit(Faulty, &tmp->rdev->flags), bdevname(tmp->rdev->bdev,b)); }} static int multipath_add_disk(mddev_t *mddev, mdk_rdev_t *rdev){ multipath_conf_t *conf = mddev->private; struct request_queue *q; int found = 0; int path; struct multipath_info *p; print_multipath_conf(conf); for (path=0; path<mddev->raid_disks; path++) if ((p=conf->multipaths+path)->rdev == NULL) { q = rdev->bdev->bd_disk->queue; blk_queue_stack_limits(mddev->queue, q); /* 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. * (Note: it is very unlikely that a device with * merge_bvec_fn will be involved in multipath.) */ if (q->merge_bvec_fn && mddev->queue->max_sectors > (PAGE_SIZE>>9)) blk_queue_max_sectors(mddev->queue, PAGE_SIZE>>9); conf->working_disks++; mddev->degraded--; rdev->raid_disk = path; set_bit(In_sync, &rdev->flags); rcu_assign_pointer(p->rdev, rdev); found = 1; } print_multipath_conf(conf); return found;} static int multipath_remove_disk(mddev_t *mddev, int number){ multipath_conf_t *conf = mddev->private; int err = 0; mdk_rdev_t *rdev; struct multipath_info *p = conf->multipaths + number; print_multipath_conf(conf); rdev = p->rdev; if (rdev) { if (test_bit(In_sync, &rdev->flags) || atomic_read(&rdev->nr_pending)) { printk(KERN_ERR "hot-remove-disk, slot %d is identified" " but is still operational!\n", number); 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_multipath_conf(conf); return err;} /* * This is a kernel thread which: * * 1. Retries failed read operations on working multipaths. * 2. Updates the raid superblock when problems encounter. * 3. Performs writes following reads for array syncronising. */ static void multipathd (mddev_t *mddev){ struct multipath_bh *mp_bh; struct bio *bio; unsigned long flags; multipath_conf_t *conf = mddev_to_conf(mddev); struct list_head *head = &conf->retry_list; md_check_recovery(mddev); for (;;) { char b[BDEVNAME_SIZE]; spin_lock_irqsave(&conf->device_lock, flags); if (list_empty(head)) break; mp_bh = list_entry(head->prev, struct multipath_bh, retry_list); list_del(head->prev); spin_unlock_irqrestore(&conf->device_lock, flags); bio = &mp_bh->bio; bio->bi_sector = mp_bh->master_bio->bi_sector; if ((mp_bh->path = multipath_map (conf))<0) { printk(KERN_ALERT "multipath: %s: unrecoverable IO read" " error for block %llu\n", bdevname(bio->bi_bdev,b), (unsigned long long)bio->bi_sector); multipath_end_bh_io(mp_bh, -EIO); } else { printk(KERN_ERR "multipath: %s: redirecting sector %llu" " to another IO path\n", bdevname(bio->bi_bdev,b), (unsigned long long)bio->bi_sector); *bio = *(mp_bh->master_bio); bio->bi_sector += conf->multipaths[mp_bh->path].rdev->data_offset; bio->bi_bdev = conf->multipaths[mp_bh->path].rdev->bdev; bio->bi_rw |= (1 << BIO_RW_FAILFAST); bio->bi_end_io = multipath_end_request; bio->bi_private = mp_bh; generic_make_request(bio); } } spin_unlock_irqrestore(&conf->device_lock, flags);} static int multipath_run (mddev_t *mddev){ multipath_conf_t *conf; int disk_idx; struct multipath_info *disk; mdk_rdev_t *rdev; struct list_head *tmp; if (mddev->level != LEVEL_MULTIPATH) { printk("multipath: %s: raid level not set to multipath IO (%d)\n", mdname(mddev), mddev->level); goto out; } /* * copy the already verified devices into our private MULTIPATH * bookkeeping area. [whatever we allocate in multipath_run(), * should be freed in multipath_stop()] */ conf = kzalloc(sizeof(multipath_conf_t), GFP_KERNEL); mddev->private = conf; if (!conf) { printk(KERN_ERR "multipath: couldn't allocate memory for %s\n", mdname(mddev)); goto out; } conf->multipaths = kzalloc(sizeof(struct multipath_info)*mddev->raid_disks, GFP_KERNEL); if (!conf->multipaths) { printk(KERN_ERR "multipath: couldn't allocate memory for %s\n", mdname(mddev)); goto out_free_conf; } conf->working_disks = 0; ITERATE_RDEV(mddev,rdev,tmp) { disk_idx = rdev->raid_disk; if (disk_idx < 0 || disk_idx >= mddev->raid_disks) continue; disk = conf->multipaths + 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, not that we ever expect a device with * a merge_bvec_fn to be involved in multipath */ 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); if (!test_bit(Faulty, &rdev->flags)) conf->working_disks++; } conf->raid_disks = mddev->raid_disks; conf->mddev = mddev; spin_lock_init(&conf->device_lock); INIT_LIST_HEAD(&conf->retry_list); Lines 1–500 of 595. 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/* * multipath.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 * * MULTIPATH management functions. * * derived from raid1.c. * * 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/module.h> #include <linux/slab.h> #include <linux/spinlock.h> #include <linux/raid/multipath.h> #include <linux/buffer_head.h> #include <asm/atomic.h> #define MAJOR_NR MD_MAJOR #define MD_DRIVER #define MD_PERSONALITY #define MAX_WORK_PER_DISK 128 #define NR_RESERVED_BUFS 32 static int multipath_map (multipath_conf_t *conf) { int i, disks = conf->raid_disks; /* * Later we do read balancing on the read side * now we use the first available disk. */ rcu_read_lock(); for (i = 0; i < disks; i++) { mdk_rdev_t *rdev = rcu_dereference(conf->multipaths[i].rdev); if (rdev && test_bit(In_sync, &rdev->flags)) { atomic_inc(&rdev->nr_pending); rcu_read_unlock(); return i; } } rcu_read_unlock(); printk(KERN_ERR "multipath_map(): no more operational IO paths?\n"); return (-1); } static void multipath_reschedule_retry (struct multipath_bh *mp_bh) { unsigned long flags; mddev_t *mddev = mp_bh->mddev; multipath_conf_t *conf = mddev_to_conf(mddev); spin_lock_irqsave(&conf->device_lock, flags); list_add(&mp_bh->retry_list, &conf->retry_list); spin_unlock_irqrestore(&conf->device_lock, flags); md_wakeup_thread(mddev->thread); } /* * multipath_end_bh_io() is called when we have finished servicing a multipathed * operation and are ready to return a success/failure code to the buffer * cache layer. */ static void multipath_end_bh_io (struct multipath_bh *mp_bh, int err) { struct bio *bio = mp_bh->master_bio; multipath_conf_t *conf = mddev_to_conf(mp_bh->mddev); bio_endio(bio, bio->bi_size, err); mempool_free(mp_bh, conf->pool); } static int multipath_end_request(struct bio *bio, unsigned int bytes_done, int error) { int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags); struct multipath_bh * mp_bh = (struct multipath_bh *)(bio->bi_private); multipath_conf_t *conf = mddev_to_conf(mp_bh->mddev); mdk_rdev_t *rdev = conf->multipaths[mp_bh->path].rdev; if (bio->bi_size) return 1; if (uptodate) multipath_end_bh_io(mp_bh, 0); else if (!bio_rw_ahead(bio)) { /* * oops, IO error: */ char b[BDEVNAME_SIZE]; md_error (mp_bh->mddev, rdev); printk(KERN_ERR "multipath: %s: rescheduling sector %llu\n", bdevname(rdev->bdev,b), (unsigned long long)bio->bi_sector); multipath_reschedule_retry(mp_bh); } else multipath_end_bh_io(mp_bh, error); rdev_dec_pending(rdev, conf->mddev); return 0; } static void unplug_slaves(mddev_t *mddev) { multipath_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->multipaths[i].rdev); if (rdev && !test_bit(Faulty, &rdev->flags) && atomic_read(&rdev->nr_pending)) { request_queue_t *r_queue = bdev_get_queue(rdev->bdev); atomic_inc(&rdev->nr_pending); rcu_read_unlock(); if (r_queue->unplug_fn) r_queue->unplug_fn(r_queue); rdev_dec_pending(rdev, mddev); rcu_read_lock(); } } rcu_read_unlock(); } static void multipath_unplug(request_queue_t *q) { unplug_slaves(q->queuedata); } static int multipath_make_request (request_queue_t *q, struct bio * bio) { mddev_t *mddev = q->queuedata; multipath_conf_t *conf = mddev_to_conf(mddev); struct multipath_bh * mp_bh; struct multipath_info *multipath; const int rw = bio_data_dir(bio); if (unlikely(bio_barrier(bio))) { bio_endio(bio, bio->bi_size, -EOPNOTSUPP); return 0; } mp_bh = mempool_alloc(conf->pool, GFP_NOIO); mp_bh->master_bio = bio; mp_bh->mddev = mddev; disk_stat_inc(mddev->gendisk, ios[rw]); disk_stat_add(mddev->gendisk, sectors[rw], bio_sectors(bio)); mp_bh->path = multipath_map(conf); if (mp_bh->path < 0) { bio_endio(bio, bio->bi_size, -EIO); mempool_free(mp_bh, conf->pool); return 0; } multipath = conf->multipaths + mp_bh->path; mp_bh->bio = *bio; mp_bh->bio.bi_sector += multipath->rdev->data_offset; mp_bh->bio.bi_bdev = multipath->rdev->bdev; mp_bh->bio.bi_rw |= (1 << BIO_RW_FAILFAST); mp_bh->bio.bi_end_io = multipath_end_request; mp_bh->bio.bi_private = mp_bh; generic_make_request(&mp_bh->bio); return 0; } static void multipath_status (struct seq_file *seq, mddev_t *mddev) { multipath_conf_t *conf = mddev_to_conf(mddev); int i; seq_printf (seq, " [%d/%d] [", conf->raid_disks, conf->working_disks); for (i = 0; i < conf->raid_disks; i++) seq_printf (seq, "%s", conf->multipaths[i].rdev && test_bit(In_sync, &conf->multipaths[i].rdev->flags) ? "U" : "_"); seq_printf (seq, "]"); } static int multipath_issue_flush(request_queue_t *q, struct gendisk *disk, sector_t *error_sector) { mddev_t *mddev = q->queuedata; multipath_conf_t *conf = mddev_to_conf(mddev); int i, ret = 0; rcu_read_lock(); for (i=0; i<mddev->raid_disks && ret == 0; i++) { mdk_rdev_t *rdev = rcu_dereference(conf->multipaths[i].rdev); if (rdev && !test_bit(Faulty, &rdev->flags)) { struct block_device *bdev = rdev->bdev; request_queue_t *r_queue = bdev_get_queue(bdev); if (!r_queue->issue_flush_fn) ret = -EOPNOTSUPP; else { atomic_inc(&rdev->nr_pending); rcu_read_unlock(); ret = r_queue->issue_flush_fn(r_queue, bdev->bd_disk, error_sector); rdev_dec_pending(rdev, mddev); rcu_read_lock(); } } } rcu_read_unlock(); return ret; } static int multipath_congested(void *data, int bits) { mddev_t *mddev = data; multipath_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->multipaths[i].rdev); if (rdev && !test_bit(Faulty, &rdev->flags)) { request_queue_t *q = bdev_get_queue(rdev->bdev); ret |= bdi_congested(&q->backing_dev_info, bits); /* Just like multipath_map, we just check the * first available device */ break; } } rcu_read_unlock(); return ret; } /* * Careful, this can execute in IRQ contexts as well! */ static void multipath_error (mddev_t *mddev, mdk_rdev_t *rdev) { multipath_conf_t *conf = mddev_to_conf(mddev); if (conf->working_disks <= 1) { /* * Uh oh, we can do nothing if this is our last path, but * first check if this is a queued request for a device * which has just failed. */ printk(KERN_ALERT "multipath: only one IO path left and IO error.\n"); /* leave it active... it's all we have */ } else { /* * Mark disk as unusable */ if (!test_bit(Faulty, &rdev->flags)) { char b[BDEVNAME_SIZE]; clear_bit(In_sync, &rdev->flags); set_bit(Faulty, &rdev->flags); set_bit(MD_CHANGE_DEVS, &mddev->flags); conf->working_disks--; mddev->degraded++; printk(KERN_ALERT "multipath: IO failure on %s," " disabling IO path. \n Operation continuing" " on %d IO paths.\n", bdevname (rdev->bdev,b), conf->working_disks); } } } static void print_multipath_conf (multipath_conf_t *conf) { int i; struct multipath_info *tmp; printk("MULTIPATH conf printout:\n"); if (!conf) { printk("(conf==NULL)\n"); return; } printk(" --- wd:%d rd:%d\n", conf->working_disks, conf->raid_disks); for (i = 0; i < conf->raid_disks; i++) { char b[BDEVNAME_SIZE]; tmp = conf->multipaths + i; if (tmp->rdev) printk(" disk%d, o:%d, dev:%s\n", i,!test_bit(Faulty, &tmp->rdev->flags), bdevname(tmp->rdev->bdev,b)); } } static int multipath_add_disk(mddev_t *mddev, mdk_rdev_t *rdev) { multipath_conf_t *conf = mddev->private; struct request_queue *q; int found = 0; int path; struct multipath_info *p; print_multipath_conf(conf); for (path=0; path<mddev->raid_disks; path++) if ((p=conf->multipaths+path)->rdev == NULL) { q = rdev->bdev->bd_disk->queue; blk_queue_stack_limits(mddev->queue, q); /* 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. * (Note: it is very unlikely that a device with * merge_bvec_fn will be involved in multipath.) */ if (q->merge_bvec_fn && mddev->queue->max_sectors > (PAGE_SIZE>>9)) blk_queue_max_sectors(mddev->queue, PAGE_SIZE>>9); conf->working_disks++; mddev->degraded--; rdev->raid_disk = path; set_bit(In_sync, &rdev->flags); rcu_assign_pointer(p->rdev, rdev); found = 1; } print_multipath_conf(conf); return found; } static int multipath_remove_disk(mddev_t *mddev, int number) { multipath_conf_t *conf = mddev->private; int err = 0; mdk_rdev_t *rdev; struct multipath_info *p = conf->multipaths + number; print_multipath_conf(conf); rdev = p->rdev; if (rdev) { if (test_bit(In_sync, &rdev->flags) || atomic_read(&rdev->nr_pending)) { printk(KERN_ERR "hot-remove-disk, slot %d is identified" " but is still operational!\n", number); 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_multipath_conf(conf); return err; } /* * This is a kernel thread which: * * 1. Retries failed read operations on working multipaths. * 2. Updates the raid superblock when problems encounter. * 3. Performs writes following reads for array syncronising. */ static void multipathd (mddev_t *mddev) { struct multipath_bh *mp_bh; struct bio *bio; unsigned long flags; multipath_conf_t *conf = mddev_to_conf(mddev); struct list_head *head = &conf->retry_list; md_check_recovery(mddev); for (;;) { char b[BDEVNAME_SIZE]; spin_lock_irqsave(&conf->device_lock, flags); if (list_empty(head)) break; mp_bh = list_entry(head->prev, struct multipath_bh, retry_list); list_del(head->prev); spin_unlock_irqrestore(&conf->device_lock, flags); bio = &mp_bh->bio; bio->bi_sector = mp_bh->master_bio->bi_sector; if ((mp_bh->path = multipath_map (conf))<0) { printk(KERN_ALERT "multipath: %s: unrecoverable IO read" " error for block %llu\n", bdevname(bio->bi_bdev,b), (unsigned long long)bio->bi_sector); multipath_end_bh_io(mp_bh, -EIO); } else { printk(KERN_ERR "multipath: %s: redirecting sector %llu" " to another IO path\n", bdevname(bio->bi_bdev,b), (unsigned long long)bio->bi_sector); *bio = *(mp_bh->master_bio); bio->bi_sector += conf->multipaths[mp_bh->path].rdev->data_offset; bio->bi_bdev = conf->multipaths[mp_bh->path].rdev->bdev; bio->bi_rw |= (1 << BIO_RW_FAILFAST); bio->bi_end_io = multipath_end_request; bio->bi_private = mp_bh; generic_make_request(bio); } } spin_unlock_irqrestore(&conf->device_lock, flags); } static int multipath_run (mddev_t *mddev) { multipath_conf_t *conf; int disk_idx; struct multipath_info *disk; mdk_rdev_t *rdev; struct list_head *tmp; if (mddev->level != LEVEL_MULTIPATH) { printk("multipath: %s: raid level not set to multipath IO (%d)\n", mdname(mddev), mddev->level); goto out; } /* * copy the already verified devices into our private MULTIPATH * bookkeeping area. [whatever we allocate in multipath_run(), * should be freed in multipath_stop()] */ conf = kzalloc(sizeof(multipath_conf_t), GFP_KERNEL); mddev->private = conf; if (!conf) { printk(KERN_ERR "multipath: couldn't allocate memory for %s\n", mdname(mddev)); goto out; } conf->multipaths = kzalloc(sizeof(struct multipath_info)*mddev->raid_disks, GFP_KERNEL); if (!conf->multipaths) { printk(KERN_ERR "multipath: couldn't allocate memory for %s\n", mdname(mddev)); goto out_free_conf; } conf->working_disks = 0; ITERATE_RDEV(mddev,rdev,tmp) { disk_idx = rdev->raid_disk; if (disk_idx < 0 || disk_idx >= mddev->raid_disks) continue; disk = conf->multipaths + 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, not that we ever expect a device with * a merge_bvec_fn to be involved in multipath */ 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); if (!test_bit(Faulty, &rdev->flags)) conf->working_disks++; } conf->raid_disks = mddev->raid_disks; conf->mddev = mddev; spin_lock_init(&conf->device_lock); INIT_LIST_HEAD(&conf->retry_list);