Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* |
| 2 | * multipath.c : Multiple Devices driver for Linux |
| 3 | * |
| 4 | * Copyright (C) 1999, 2000, 2001 Ingo Molnar, Red Hat |
| 5 | * |
| 6 | * Copyright (C) 1996, 1997, 1998 Ingo Molnar, Miguel de Icaza, Gadi Oxman |
| 7 | * |
| 8 | * MULTIPATH management functions. |
| 9 | * |
| 10 | * derived from raid1.c. |
| 11 | * |
| 12 | * This program is free software; you can redistribute it and/or modify |
| 13 | * it under the terms of the GNU General Public License as published by |
| 14 | * the Free Software Foundation; either version 2, or (at your option) |
| 15 | * any later version. |
| 16 | * |
| 17 | * You should have received a copy of the GNU General Public License |
| 18 | * (for example /usr/src/linux/COPYING); if not, write to the Free |
| 19 | * Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. |
| 20 | */ |
| 21 | |
NeilBrown | bff6197 | 2009-03-31 14:33:13 +1100 | [diff] [blame] | 22 | #include <linux/blkdev.h> |
| 23 | #include <linux/raid/md_u.h> |
NeilBrown | bff6197 | 2009-03-31 14:33:13 +1100 | [diff] [blame] | 24 | #include <linux/seq_file.h> |
Tejun Heo | 5a0e3ad | 2010-03-24 17:04:11 +0900 | [diff] [blame] | 25 | #include <linux/slab.h> |
NeilBrown | 43b2e5d | 2009-03-31 14:33:13 +1100 | [diff] [blame] | 26 | #include "md.h" |
Christoph Hellwig | ef740c3 | 2009-03-31 14:27:03 +1100 | [diff] [blame] | 27 | #include "multipath.h" |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 28 | |
| 29 | #define MAX_WORK_PER_DISK 128 |
| 30 | |
| 31 | #define NR_RESERVED_BUFS 32 |
| 32 | |
| 33 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 34 | static int multipath_map (multipath_conf_t *conf) |
| 35 | { |
| 36 | int i, disks = conf->raid_disks; |
| 37 | |
| 38 | /* |
| 39 | * Later we do read balancing on the read side |
| 40 | * now we use the first available disk. |
| 41 | */ |
| 42 | |
| 43 | rcu_read_lock(); |
| 44 | for (i = 0; i < disks; i++) { |
NeilBrown | 3cb0300 | 2011-10-11 16:45:26 +1100 | [diff] [blame] | 45 | struct md_rdev *rdev = rcu_dereference(conf->multipaths[i].rdev); |
NeilBrown | b2d444d | 2005-11-08 21:39:31 -0800 | [diff] [blame] | 46 | if (rdev && test_bit(In_sync, &rdev->flags)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 47 | atomic_inc(&rdev->nr_pending); |
| 48 | rcu_read_unlock(); |
| 49 | return i; |
| 50 | } |
| 51 | } |
| 52 | rcu_read_unlock(); |
| 53 | |
| 54 | printk(KERN_ERR "multipath_map(): no more operational IO paths?\n"); |
| 55 | return (-1); |
| 56 | } |
| 57 | |
| 58 | static void multipath_reschedule_retry (struct multipath_bh *mp_bh) |
| 59 | { |
| 60 | unsigned long flags; |
NeilBrown | fd01b88 | 2011-10-11 16:47:53 +1100 | [diff] [blame^] | 61 | struct mddev *mddev = mp_bh->mddev; |
NeilBrown | 070ec55 | 2009-06-16 16:54:21 +1000 | [diff] [blame] | 62 | multipath_conf_t *conf = mddev->private; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 63 | |
| 64 | spin_lock_irqsave(&conf->device_lock, flags); |
| 65 | list_add(&mp_bh->retry_list, &conf->retry_list); |
| 66 | spin_unlock_irqrestore(&conf->device_lock, flags); |
| 67 | md_wakeup_thread(mddev->thread); |
| 68 | } |
| 69 | |
| 70 | |
| 71 | /* |
| 72 | * multipath_end_bh_io() is called when we have finished servicing a multipathed |
| 73 | * operation and are ready to return a success/failure code to the buffer |
| 74 | * cache layer. |
| 75 | */ |
| 76 | static void multipath_end_bh_io (struct multipath_bh *mp_bh, int err) |
| 77 | { |
| 78 | struct bio *bio = mp_bh->master_bio; |
NeilBrown | 070ec55 | 2009-06-16 16:54:21 +1000 | [diff] [blame] | 79 | multipath_conf_t *conf = mp_bh->mddev->private; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 80 | |
NeilBrown | 6712ecf | 2007-09-27 12:47:43 +0200 | [diff] [blame] | 81 | bio_endio(bio, err); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 82 | mempool_free(mp_bh, conf->pool); |
| 83 | } |
| 84 | |
NeilBrown | 6712ecf | 2007-09-27 12:47:43 +0200 | [diff] [blame] | 85 | static void multipath_end_request(struct bio *bio, int error) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 86 | { |
| 87 | int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags); |
H Hartley Sweeten | 7b92813 | 2010-03-08 16:02:40 +1100 | [diff] [blame] | 88 | struct multipath_bh *mp_bh = bio->bi_private; |
NeilBrown | 070ec55 | 2009-06-16 16:54:21 +1000 | [diff] [blame] | 89 | multipath_conf_t *conf = mp_bh->mddev->private; |
NeilBrown | 3cb0300 | 2011-10-11 16:45:26 +1100 | [diff] [blame] | 90 | struct md_rdev *rdev = conf->multipaths[mp_bh->path].rdev; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 91 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 92 | if (uptodate) |
| 93 | multipath_end_bh_io(mp_bh, 0); |
Christoph Hellwig | 7b6d91d | 2010-08-07 18:20:39 +0200 | [diff] [blame] | 94 | else if (!(bio->bi_rw & REQ_RAHEAD)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 95 | /* |
| 96 | * oops, IO error: |
| 97 | */ |
| 98 | char b[BDEVNAME_SIZE]; |
| 99 | md_error (mp_bh->mddev, rdev); |
| 100 | printk(KERN_ERR "multipath: %s: rescheduling sector %llu\n", |
| 101 | bdevname(rdev->bdev,b), |
| 102 | (unsigned long long)bio->bi_sector); |
| 103 | multipath_reschedule_retry(mp_bh); |
| 104 | } else |
| 105 | multipath_end_bh_io(mp_bh, error); |
| 106 | rdev_dec_pending(rdev, conf->mddev); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 107 | } |
| 108 | |
NeilBrown | fd01b88 | 2011-10-11 16:47:53 +1100 | [diff] [blame^] | 109 | static int multipath_make_request(struct mddev *mddev, struct bio * bio) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 110 | { |
NeilBrown | 070ec55 | 2009-06-16 16:54:21 +1000 | [diff] [blame] | 111 | multipath_conf_t *conf = mddev->private; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 112 | struct multipath_bh * mp_bh; |
| 113 | struct multipath_info *multipath; |
| 114 | |
Tejun Heo | e9c7469 | 2010-09-03 11:56:18 +0200 | [diff] [blame] | 115 | if (unlikely(bio->bi_rw & REQ_FLUSH)) { |
| 116 | md_flush_request(mddev, bio); |
NeilBrown | e5dcdd8 | 2005-09-09 16:23:41 -0700 | [diff] [blame] | 117 | return 0; |
| 118 | } |
| 119 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 120 | mp_bh = mempool_alloc(conf->pool, GFP_NOIO); |
| 121 | |
| 122 | mp_bh->master_bio = bio; |
| 123 | mp_bh->mddev = mddev; |
| 124 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 125 | mp_bh->path = multipath_map(conf); |
| 126 | if (mp_bh->path < 0) { |
NeilBrown | 6712ecf | 2007-09-27 12:47:43 +0200 | [diff] [blame] | 127 | bio_endio(bio, -EIO); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 128 | mempool_free(mp_bh, conf->pool); |
| 129 | return 0; |
| 130 | } |
| 131 | multipath = conf->multipaths + mp_bh->path; |
| 132 | |
| 133 | mp_bh->bio = *bio; |
| 134 | mp_bh->bio.bi_sector += multipath->rdev->data_offset; |
| 135 | mp_bh->bio.bi_bdev = multipath->rdev->bdev; |
Christoph Hellwig | 7b6d91d | 2010-08-07 18:20:39 +0200 | [diff] [blame] | 136 | mp_bh->bio.bi_rw |= REQ_FAILFAST_TRANSPORT; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 137 | mp_bh->bio.bi_end_io = multipath_end_request; |
| 138 | mp_bh->bio.bi_private = mp_bh; |
| 139 | generic_make_request(&mp_bh->bio); |
| 140 | return 0; |
| 141 | } |
| 142 | |
NeilBrown | fd01b88 | 2011-10-11 16:47:53 +1100 | [diff] [blame^] | 143 | static void multipath_status (struct seq_file *seq, struct mddev *mddev) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 144 | { |
NeilBrown | 070ec55 | 2009-06-16 16:54:21 +1000 | [diff] [blame] | 145 | multipath_conf_t *conf = mddev->private; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 146 | int i; |
| 147 | |
| 148 | seq_printf (seq, " [%d/%d] [", conf->raid_disks, |
NeilBrown | 92f861a | 2011-05-11 14:38:02 +1000 | [diff] [blame] | 149 | conf->raid_disks - mddev->degraded); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 150 | for (i = 0; i < conf->raid_disks; i++) |
| 151 | seq_printf (seq, "%s", |
| 152 | conf->multipaths[i].rdev && |
NeilBrown | b2d444d | 2005-11-08 21:39:31 -0800 | [diff] [blame] | 153 | test_bit(In_sync, &conf->multipaths[i].rdev->flags) ? "U" : "_"); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 154 | seq_printf (seq, "]"); |
| 155 | } |
| 156 | |
NeilBrown | 0d12922 | 2006-10-03 01:15:54 -0700 | [diff] [blame] | 157 | static int multipath_congested(void *data, int bits) |
| 158 | { |
NeilBrown | fd01b88 | 2011-10-11 16:47:53 +1100 | [diff] [blame^] | 159 | struct mddev *mddev = data; |
NeilBrown | 070ec55 | 2009-06-16 16:54:21 +1000 | [diff] [blame] | 160 | multipath_conf_t *conf = mddev->private; |
NeilBrown | 0d12922 | 2006-10-03 01:15:54 -0700 | [diff] [blame] | 161 | int i, ret = 0; |
| 162 | |
NeilBrown | 3fa841d | 2009-09-23 18:10:29 +1000 | [diff] [blame] | 163 | if (mddev_congested(mddev, bits)) |
| 164 | return 1; |
| 165 | |
NeilBrown | 0d12922 | 2006-10-03 01:15:54 -0700 | [diff] [blame] | 166 | rcu_read_lock(); |
| 167 | for (i = 0; i < mddev->raid_disks ; i++) { |
NeilBrown | 3cb0300 | 2011-10-11 16:45:26 +1100 | [diff] [blame] | 168 | struct md_rdev *rdev = rcu_dereference(conf->multipaths[i].rdev); |
NeilBrown | 0d12922 | 2006-10-03 01:15:54 -0700 | [diff] [blame] | 169 | if (rdev && !test_bit(Faulty, &rdev->flags)) { |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 170 | struct request_queue *q = bdev_get_queue(rdev->bdev); |
NeilBrown | 0d12922 | 2006-10-03 01:15:54 -0700 | [diff] [blame] | 171 | |
| 172 | ret |= bdi_congested(&q->backing_dev_info, bits); |
| 173 | /* Just like multipath_map, we just check the |
| 174 | * first available device |
| 175 | */ |
| 176 | break; |
| 177 | } |
| 178 | } |
| 179 | rcu_read_unlock(); |
| 180 | return ret; |
| 181 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 182 | |
| 183 | /* |
| 184 | * Careful, this can execute in IRQ contexts as well! |
| 185 | */ |
NeilBrown | fd01b88 | 2011-10-11 16:47:53 +1100 | [diff] [blame^] | 186 | static void multipath_error (struct mddev *mddev, struct md_rdev *rdev) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 187 | { |
NeilBrown | 070ec55 | 2009-06-16 16:54:21 +1000 | [diff] [blame] | 188 | multipath_conf_t *conf = mddev->private; |
NeilBrown | 6f8d0c7 | 2011-05-11 14:38:44 +1000 | [diff] [blame] | 189 | char b[BDEVNAME_SIZE]; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 190 | |
NeilBrown | 92f861a | 2011-05-11 14:38:02 +1000 | [diff] [blame] | 191 | if (conf->raid_disks - mddev->degraded <= 1) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 192 | /* |
| 193 | * Uh oh, we can do nothing if this is our last path, but |
| 194 | * first check if this is a queued request for a device |
| 195 | * which has just failed. |
| 196 | */ |
| 197 | printk(KERN_ALERT |
NeilBrown | 6f8d0c7 | 2011-05-11 14:38:44 +1000 | [diff] [blame] | 198 | "multipath: only one IO path left and IO error.\n"); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 199 | /* leave it active... it's all we have */ |
NeilBrown | 6f8d0c7 | 2011-05-11 14:38:44 +1000 | [diff] [blame] | 200 | return; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 201 | } |
NeilBrown | 6f8d0c7 | 2011-05-11 14:38:44 +1000 | [diff] [blame] | 202 | /* |
| 203 | * Mark disk as unusable |
| 204 | */ |
| 205 | if (test_and_clear_bit(In_sync, &rdev->flags)) { |
| 206 | unsigned long flags; |
| 207 | spin_lock_irqsave(&conf->device_lock, flags); |
| 208 | mddev->degraded++; |
| 209 | spin_unlock_irqrestore(&conf->device_lock, flags); |
| 210 | } |
| 211 | set_bit(Faulty, &rdev->flags); |
| 212 | set_bit(MD_CHANGE_DEVS, &mddev->flags); |
| 213 | printk(KERN_ALERT "multipath: IO failure on %s," |
| 214 | " disabling IO path.\n" |
| 215 | "multipath: Operation continuing" |
| 216 | " on %d IO paths.\n", |
| 217 | bdevname(rdev->bdev, b), |
| 218 | conf->raid_disks - mddev->degraded); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 219 | } |
| 220 | |
| 221 | static void print_multipath_conf (multipath_conf_t *conf) |
| 222 | { |
| 223 | int i; |
| 224 | struct multipath_info *tmp; |
| 225 | |
| 226 | printk("MULTIPATH conf printout:\n"); |
| 227 | if (!conf) { |
| 228 | printk("(conf==NULL)\n"); |
| 229 | return; |
| 230 | } |
NeilBrown | 92f861a | 2011-05-11 14:38:02 +1000 | [diff] [blame] | 231 | printk(" --- wd:%d rd:%d\n", conf->raid_disks - conf->mddev->degraded, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 232 | conf->raid_disks); |
| 233 | |
| 234 | for (i = 0; i < conf->raid_disks; i++) { |
| 235 | char b[BDEVNAME_SIZE]; |
| 236 | tmp = conf->multipaths + i; |
| 237 | if (tmp->rdev) |
| 238 | printk(" disk%d, o:%d, dev:%s\n", |
NeilBrown | b2d444d | 2005-11-08 21:39:31 -0800 | [diff] [blame] | 239 | i,!test_bit(Faulty, &tmp->rdev->flags), |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 240 | bdevname(tmp->rdev->bdev,b)); |
| 241 | } |
| 242 | } |
| 243 | |
| 244 | |
NeilBrown | fd01b88 | 2011-10-11 16:47:53 +1100 | [diff] [blame^] | 245 | static int multipath_add_disk(struct mddev *mddev, struct md_rdev *rdev) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 246 | { |
| 247 | multipath_conf_t *conf = mddev->private; |
Jesper Juhl | 352d768 | 2006-01-09 20:54:44 -0800 | [diff] [blame] | 248 | struct request_queue *q; |
Neil Brown | 199050e | 2008-06-28 08:31:33 +1000 | [diff] [blame] | 249 | int err = -EEXIST; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 250 | int path; |
| 251 | struct multipath_info *p; |
Neil Brown | 6c2fce2 | 2008-06-28 08:31:31 +1000 | [diff] [blame] | 252 | int first = 0; |
| 253 | int last = mddev->raid_disks - 1; |
| 254 | |
| 255 | if (rdev->raid_disk >= 0) |
| 256 | first = last = rdev->raid_disk; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 257 | |
| 258 | print_multipath_conf(conf); |
| 259 | |
Neil Brown | 6c2fce2 | 2008-06-28 08:31:31 +1000 | [diff] [blame] | 260 | for (path = first; path <= last; path++) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 261 | if ((p=conf->multipaths+path)->rdev == NULL) { |
Jesper Juhl | 352d768 | 2006-01-09 20:54:44 -0800 | [diff] [blame] | 262 | q = rdev->bdev->bd_disk->queue; |
Martin K. Petersen | 8f6c2e4 | 2009-07-01 11:13:45 +1000 | [diff] [blame] | 263 | disk_stack_limits(mddev->gendisk, rdev->bdev, |
| 264 | rdev->data_offset << 9); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 265 | |
| 266 | /* as we don't honour merge_bvec_fn, we must never risk |
NeilBrown | 627a2d3 | 2010-03-08 16:44:38 +1100 | [diff] [blame] | 267 | * violating it, so limit ->max_segments to one, lying |
| 268 | * within a single page. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 269 | * (Note: it is very unlikely that a device with |
| 270 | * merge_bvec_fn will be involved in multipath.) |
| 271 | */ |
NeilBrown | 627a2d3 | 2010-03-08 16:44:38 +1100 | [diff] [blame] | 272 | if (q->merge_bvec_fn) { |
| 273 | blk_queue_max_segments(mddev->queue, 1); |
| 274 | blk_queue_segment_boundary(mddev->queue, |
| 275 | PAGE_CACHE_SIZE - 1); |
| 276 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 277 | |
NeilBrown | 6f8d0c7 | 2011-05-11 14:38:44 +1000 | [diff] [blame] | 278 | spin_lock_irq(&conf->device_lock); |
NeilBrown | 750a8f3 | 2006-10-28 10:38:31 -0700 | [diff] [blame] | 279 | mddev->degraded--; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 280 | rdev->raid_disk = path; |
NeilBrown | b2d444d | 2005-11-08 21:39:31 -0800 | [diff] [blame] | 281 | set_bit(In_sync, &rdev->flags); |
NeilBrown | 6f8d0c7 | 2011-05-11 14:38:44 +1000 | [diff] [blame] | 282 | spin_unlock_irq(&conf->device_lock); |
Suzanne Wood | d6065f7 | 2005-11-08 21:39:27 -0800 | [diff] [blame] | 283 | rcu_assign_pointer(p->rdev, rdev); |
Neil Brown | 199050e | 2008-06-28 08:31:33 +1000 | [diff] [blame] | 284 | err = 0; |
Andre Noll | ac5e711 | 2009-08-03 10:59:47 +1000 | [diff] [blame] | 285 | md_integrity_add_rdev(rdev, mddev); |
Neil Brown | 199050e | 2008-06-28 08:31:33 +1000 | [diff] [blame] | 286 | break; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 287 | } |
| 288 | |
| 289 | print_multipath_conf(conf); |
Neil Brown | 199050e | 2008-06-28 08:31:33 +1000 | [diff] [blame] | 290 | |
| 291 | return err; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 292 | } |
| 293 | |
NeilBrown | fd01b88 | 2011-10-11 16:47:53 +1100 | [diff] [blame^] | 294 | static int multipath_remove_disk(struct mddev *mddev, int number) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 295 | { |
| 296 | multipath_conf_t *conf = mddev->private; |
| 297 | int err = 0; |
NeilBrown | 3cb0300 | 2011-10-11 16:45:26 +1100 | [diff] [blame] | 298 | struct md_rdev *rdev; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 299 | struct multipath_info *p = conf->multipaths + number; |
| 300 | |
| 301 | print_multipath_conf(conf); |
| 302 | |
| 303 | rdev = p->rdev; |
| 304 | if (rdev) { |
NeilBrown | b2d444d | 2005-11-08 21:39:31 -0800 | [diff] [blame] | 305 | if (test_bit(In_sync, &rdev->flags) || |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 306 | atomic_read(&rdev->nr_pending)) { |
NeilBrown | dfc7064 | 2008-05-23 13:04:39 -0700 | [diff] [blame] | 307 | printk(KERN_ERR "hot-remove-disk, slot %d is identified" |
| 308 | " but is still operational!\n", number); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 309 | err = -EBUSY; |
| 310 | goto abort; |
| 311 | } |
| 312 | p->rdev = NULL; |
Paul E. McKenney | fbd568a3e | 2005-05-01 08:59:04 -0700 | [diff] [blame] | 313 | synchronize_rcu(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 314 | if (atomic_read(&rdev->nr_pending)) { |
| 315 | /* lost the race, try later */ |
| 316 | err = -EBUSY; |
| 317 | p->rdev = rdev; |
Andre Noll | ac5e711 | 2009-08-03 10:59:47 +1000 | [diff] [blame] | 318 | goto abort; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 319 | } |
Martin K. Petersen | a91a278 | 2011-03-17 11:11:05 +0100 | [diff] [blame] | 320 | err = md_integrity_register(mddev); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 321 | } |
| 322 | abort: |
| 323 | |
| 324 | print_multipath_conf(conf); |
| 325 | return err; |
| 326 | } |
| 327 | |
| 328 | |
| 329 | |
| 330 | /* |
| 331 | * This is a kernel thread which: |
| 332 | * |
| 333 | * 1. Retries failed read operations on working multipaths. |
| 334 | * 2. Updates the raid superblock when problems encounter. |
| 335 | * 3. Performs writes following reads for array syncronising. |
| 336 | */ |
| 337 | |
NeilBrown | fd01b88 | 2011-10-11 16:47:53 +1100 | [diff] [blame^] | 338 | static void multipathd (struct mddev *mddev) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 339 | { |
| 340 | struct multipath_bh *mp_bh; |
| 341 | struct bio *bio; |
| 342 | unsigned long flags; |
NeilBrown | 070ec55 | 2009-06-16 16:54:21 +1000 | [diff] [blame] | 343 | multipath_conf_t *conf = mddev->private; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 344 | struct list_head *head = &conf->retry_list; |
| 345 | |
| 346 | md_check_recovery(mddev); |
| 347 | for (;;) { |
| 348 | char b[BDEVNAME_SIZE]; |
| 349 | spin_lock_irqsave(&conf->device_lock, flags); |
| 350 | if (list_empty(head)) |
| 351 | break; |
| 352 | mp_bh = list_entry(head->prev, struct multipath_bh, retry_list); |
| 353 | list_del(head->prev); |
| 354 | spin_unlock_irqrestore(&conf->device_lock, flags); |
| 355 | |
| 356 | bio = &mp_bh->bio; |
| 357 | bio->bi_sector = mp_bh->master_bio->bi_sector; |
| 358 | |
| 359 | if ((mp_bh->path = multipath_map (conf))<0) { |
| 360 | printk(KERN_ALERT "multipath: %s: unrecoverable IO read" |
| 361 | " error for block %llu\n", |
| 362 | bdevname(bio->bi_bdev,b), |
| 363 | (unsigned long long)bio->bi_sector); |
| 364 | multipath_end_bh_io(mp_bh, -EIO); |
| 365 | } else { |
| 366 | printk(KERN_ERR "multipath: %s: redirecting sector %llu" |
| 367 | " to another IO path\n", |
| 368 | bdevname(bio->bi_bdev,b), |
| 369 | (unsigned long long)bio->bi_sector); |
| 370 | *bio = *(mp_bh->master_bio); |
| 371 | bio->bi_sector += conf->multipaths[mp_bh->path].rdev->data_offset; |
| 372 | bio->bi_bdev = conf->multipaths[mp_bh->path].rdev->bdev; |
Christoph Hellwig | 7b6d91d | 2010-08-07 18:20:39 +0200 | [diff] [blame] | 373 | bio->bi_rw |= REQ_FAILFAST_TRANSPORT; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 374 | bio->bi_end_io = multipath_end_request; |
| 375 | bio->bi_private = mp_bh; |
| 376 | generic_make_request(bio); |
| 377 | } |
| 378 | } |
| 379 | spin_unlock_irqrestore(&conf->device_lock, flags); |
| 380 | } |
| 381 | |
NeilBrown | fd01b88 | 2011-10-11 16:47:53 +1100 | [diff] [blame^] | 382 | static sector_t multipath_size(struct mddev *mddev, sector_t sectors, int raid_disks) |
Dan Williams | 80c3a6c | 2009-03-17 18:10:40 -0700 | [diff] [blame] | 383 | { |
| 384 | WARN_ONCE(sectors || raid_disks, |
| 385 | "%s does not support generic reshape\n", __func__); |
| 386 | |
| 387 | return mddev->dev_sectors; |
| 388 | } |
| 389 | |
NeilBrown | fd01b88 | 2011-10-11 16:47:53 +1100 | [diff] [blame^] | 390 | static int multipath_run (struct mddev *mddev) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 391 | { |
| 392 | multipath_conf_t *conf; |
| 393 | int disk_idx; |
| 394 | struct multipath_info *disk; |
NeilBrown | 3cb0300 | 2011-10-11 16:45:26 +1100 | [diff] [blame] | 395 | struct md_rdev *rdev; |
NeilBrown | 92f861a | 2011-05-11 14:38:02 +1000 | [diff] [blame] | 396 | int working_disks; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 397 | |
Andre Noll | 0894cc3 | 2009-06-18 08:49:23 +1000 | [diff] [blame] | 398 | if (md_check_no_bitmap(mddev)) |
| 399 | return -EINVAL; |
| 400 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 401 | if (mddev->level != LEVEL_MULTIPATH) { |
| 402 | printk("multipath: %s: raid level not set to multipath IO (%d)\n", |
| 403 | mdname(mddev), mddev->level); |
| 404 | goto out; |
| 405 | } |
| 406 | /* |
| 407 | * copy the already verified devices into our private MULTIPATH |
| 408 | * bookkeeping area. [whatever we allocate in multipath_run(), |
| 409 | * should be freed in multipath_stop()] |
| 410 | */ |
| 411 | |
NeilBrown | 9ffae0c | 2006-01-06 00:20:32 -0800 | [diff] [blame] | 412 | conf = kzalloc(sizeof(multipath_conf_t), GFP_KERNEL); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 413 | mddev->private = conf; |
| 414 | if (!conf) { |
| 415 | printk(KERN_ERR |
| 416 | "multipath: couldn't allocate memory for %s\n", |
| 417 | mdname(mddev)); |
| 418 | goto out; |
| 419 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 420 | |
NeilBrown | 9ffae0c | 2006-01-06 00:20:32 -0800 | [diff] [blame] | 421 | conf->multipaths = kzalloc(sizeof(struct multipath_info)*mddev->raid_disks, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 422 | GFP_KERNEL); |
| 423 | if (!conf->multipaths) { |
| 424 | printk(KERN_ERR |
| 425 | "multipath: couldn't allocate memory for %s\n", |
| 426 | mdname(mddev)); |
| 427 | goto out_free_conf; |
| 428 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 429 | |
NeilBrown | 92f861a | 2011-05-11 14:38:02 +1000 | [diff] [blame] | 430 | working_disks = 0; |
Cheng Renquan | 159ec1f | 2009-01-09 08:31:08 +1100 | [diff] [blame] | 431 | list_for_each_entry(rdev, &mddev->disks, same_set) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 432 | disk_idx = rdev->raid_disk; |
| 433 | if (disk_idx < 0 || |
| 434 | disk_idx >= mddev->raid_disks) |
| 435 | continue; |
| 436 | |
| 437 | disk = conf->multipaths + disk_idx; |
| 438 | disk->rdev = rdev; |
Martin K. Petersen | 8f6c2e4 | 2009-07-01 11:13:45 +1000 | [diff] [blame] | 439 | disk_stack_limits(mddev->gendisk, rdev->bdev, |
| 440 | rdev->data_offset << 9); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 441 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 442 | /* as we don't honour merge_bvec_fn, we must never risk |
| 443 | * violating it, not that we ever expect a device with |
| 444 | * a merge_bvec_fn to be involved in multipath */ |
NeilBrown | 627a2d3 | 2010-03-08 16:44:38 +1100 | [diff] [blame] | 445 | if (rdev->bdev->bd_disk->queue->merge_bvec_fn) { |
| 446 | blk_queue_max_segments(mddev->queue, 1); |
| 447 | blk_queue_segment_boundary(mddev->queue, |
| 448 | PAGE_CACHE_SIZE - 1); |
| 449 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 450 | |
NeilBrown | b2d444d | 2005-11-08 21:39:31 -0800 | [diff] [blame] | 451 | if (!test_bit(Faulty, &rdev->flags)) |
NeilBrown | 92f861a | 2011-05-11 14:38:02 +1000 | [diff] [blame] | 452 | working_disks++; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 453 | } |
| 454 | |
| 455 | conf->raid_disks = mddev->raid_disks; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 456 | conf->mddev = mddev; |
| 457 | spin_lock_init(&conf->device_lock); |
| 458 | INIT_LIST_HEAD(&conf->retry_list); |
| 459 | |
NeilBrown | 92f861a | 2011-05-11 14:38:02 +1000 | [diff] [blame] | 460 | if (!working_disks) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 461 | printk(KERN_ERR "multipath: no operational IO paths for %s\n", |
| 462 | mdname(mddev)); |
| 463 | goto out_free_conf; |
| 464 | } |
NeilBrown | 92f861a | 2011-05-11 14:38:02 +1000 | [diff] [blame] | 465 | mddev->degraded = conf->raid_disks - working_disks; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 466 | |
Sage Weil | bbba809 | 2009-09-21 17:02:55 -0700 | [diff] [blame] | 467 | conf->pool = mempool_create_kmalloc_pool(NR_RESERVED_BUFS, |
Matthew Dobson | 26b6e05 | 2006-03-26 01:37:48 -0800 | [diff] [blame] | 468 | sizeof(struct multipath_bh)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 469 | if (conf->pool == NULL) { |
| 470 | printk(KERN_ERR |
| 471 | "multipath: couldn't allocate memory for %s\n", |
| 472 | mdname(mddev)); |
| 473 | goto out_free_conf; |
| 474 | } |
| 475 | |
| 476 | { |
NeilBrown | 0da3c61 | 2009-09-23 18:09:45 +1000 | [diff] [blame] | 477 | mddev->thread = md_register_thread(multipathd, mddev, NULL); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 478 | if (!mddev->thread) { |
| 479 | printk(KERN_ERR "multipath: couldn't allocate thread" |
| 480 | " for %s\n", mdname(mddev)); |
| 481 | goto out_free_conf; |
| 482 | } |
| 483 | } |
| 484 | |
| 485 | printk(KERN_INFO |
| 486 | "multipath: array %s active with %d out of %d IO paths\n", |
NeilBrown | 92f861a | 2011-05-11 14:38:02 +1000 | [diff] [blame] | 487 | mdname(mddev), conf->raid_disks - mddev->degraded, |
| 488 | mddev->raid_disks); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 489 | /* |
| 490 | * Ok, everything is just fine now |
| 491 | */ |
Dan Williams | 1f40362 | 2009-03-31 14:59:03 +1100 | [diff] [blame] | 492 | md_set_array_sectors(mddev, multipath_size(mddev, 0, 0)); |
NeilBrown | 7a5febe | 2005-05-16 21:53:16 -0700 | [diff] [blame] | 493 | |
NeilBrown | 0d12922 | 2006-10-03 01:15:54 -0700 | [diff] [blame] | 494 | mddev->queue->backing_dev_info.congested_fn = multipath_congested; |
| 495 | mddev->queue->backing_dev_info.congested_data = mddev; |
Martin K. Petersen | a91a278 | 2011-03-17 11:11:05 +0100 | [diff] [blame] | 496 | |
| 497 | if (md_integrity_register(mddev)) |
| 498 | goto out_free_conf; |
| 499 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 500 | return 0; |
| 501 | |
| 502 | out_free_conf: |
| 503 | if (conf->pool) |
| 504 | mempool_destroy(conf->pool); |
Jesper Juhl | 990a8ba | 2005-06-21 17:17:30 -0700 | [diff] [blame] | 505 | kfree(conf->multipaths); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 506 | kfree(conf); |
| 507 | mddev->private = NULL; |
| 508 | out: |
| 509 | return -EIO; |
| 510 | } |
| 511 | |
| 512 | |
NeilBrown | fd01b88 | 2011-10-11 16:47:53 +1100 | [diff] [blame^] | 513 | static int multipath_stop (struct mddev *mddev) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 514 | { |
NeilBrown | 070ec55 | 2009-06-16 16:54:21 +1000 | [diff] [blame] | 515 | multipath_conf_t *conf = mddev->private; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 516 | |
NeilBrown | 01f96c0 | 2011-09-21 15:30:20 +1000 | [diff] [blame] | 517 | md_unregister_thread(&mddev->thread); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 518 | blk_sync_queue(mddev->queue); /* the unplug fn references 'conf'*/ |
| 519 | mempool_destroy(conf->pool); |
| 520 | kfree(conf->multipaths); |
| 521 | kfree(conf); |
| 522 | mddev->private = NULL; |
| 523 | return 0; |
| 524 | } |
| 525 | |
NeilBrown | 2604b70 | 2006-01-06 00:20:36 -0800 | [diff] [blame] | 526 | static struct mdk_personality multipath_personality = |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 527 | { |
| 528 | .name = "multipath", |
NeilBrown | 2604b70 | 2006-01-06 00:20:36 -0800 | [diff] [blame] | 529 | .level = LEVEL_MULTIPATH, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 530 | .owner = THIS_MODULE, |
| 531 | .make_request = multipath_make_request, |
| 532 | .run = multipath_run, |
| 533 | .stop = multipath_stop, |
| 534 | .status = multipath_status, |
| 535 | .error_handler = multipath_error, |
| 536 | .hot_add_disk = multipath_add_disk, |
| 537 | .hot_remove_disk= multipath_remove_disk, |
Dan Williams | 80c3a6c | 2009-03-17 18:10:40 -0700 | [diff] [blame] | 538 | .size = multipath_size, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 539 | }; |
| 540 | |
| 541 | static int __init multipath_init (void) |
| 542 | { |
NeilBrown | 2604b70 | 2006-01-06 00:20:36 -0800 | [diff] [blame] | 543 | return register_md_personality (&multipath_personality); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 544 | } |
| 545 | |
| 546 | static void __exit multipath_exit (void) |
| 547 | { |
NeilBrown | 2604b70 | 2006-01-06 00:20:36 -0800 | [diff] [blame] | 548 | unregister_md_personality (&multipath_personality); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 549 | } |
| 550 | |
| 551 | module_init(multipath_init); |
| 552 | module_exit(multipath_exit); |
| 553 | MODULE_LICENSE("GPL"); |
NeilBrown | 0efb9e6 | 2009-12-14 12:49:58 +1100 | [diff] [blame] | 554 | MODULE_DESCRIPTION("simple multi-path personality for MD"); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 555 | MODULE_ALIAS("md-personality-7"); /* MULTIPATH */ |
NeilBrown | d9d166c | 2006-01-06 00:20:51 -0800 | [diff] [blame] | 556 | MODULE_ALIAS("md-multipath"); |
NeilBrown | 2604b70 | 2006-01-06 00:20:36 -0800 | [diff] [blame] | 557 | MODULE_ALIAS("md-level--4"); |