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> |
NeilBrown | 43b2e5d | 2009-03-31 14:33:13 +1100 | [diff] [blame] | 25 | #include "md.h" |
Christoph Hellwig | ef740c3 | 2009-03-31 14:27:03 +1100 | [diff] [blame] | 26 | #include "multipath.h" |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 27 | |
| 28 | #define MAX_WORK_PER_DISK 128 |
| 29 | |
| 30 | #define NR_RESERVED_BUFS 32 |
| 31 | |
| 32 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 33 | static int multipath_map (multipath_conf_t *conf) |
| 34 | { |
| 35 | int i, disks = conf->raid_disks; |
| 36 | |
| 37 | /* |
| 38 | * Later we do read balancing on the read side |
| 39 | * now we use the first available disk. |
| 40 | */ |
| 41 | |
| 42 | rcu_read_lock(); |
| 43 | for (i = 0; i < disks; i++) { |
Suzanne Wood | d6065f7 | 2005-11-08 21:39:27 -0800 | [diff] [blame] | 44 | mdk_rdev_t *rdev = rcu_dereference(conf->multipaths[i].rdev); |
NeilBrown | b2d444d | 2005-11-08 21:39:31 -0800 | [diff] [blame] | 45 | if (rdev && test_bit(In_sync, &rdev->flags)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 46 | atomic_inc(&rdev->nr_pending); |
| 47 | rcu_read_unlock(); |
| 48 | return i; |
| 49 | } |
| 50 | } |
| 51 | rcu_read_unlock(); |
| 52 | |
| 53 | printk(KERN_ERR "multipath_map(): no more operational IO paths?\n"); |
| 54 | return (-1); |
| 55 | } |
| 56 | |
| 57 | static void multipath_reschedule_retry (struct multipath_bh *mp_bh) |
| 58 | { |
| 59 | unsigned long flags; |
| 60 | mddev_t *mddev = mp_bh->mddev; |
| 61 | multipath_conf_t *conf = mddev_to_conf(mddev); |
| 62 | |
| 63 | spin_lock_irqsave(&conf->device_lock, flags); |
| 64 | list_add(&mp_bh->retry_list, &conf->retry_list); |
| 65 | spin_unlock_irqrestore(&conf->device_lock, flags); |
| 66 | md_wakeup_thread(mddev->thread); |
| 67 | } |
| 68 | |
| 69 | |
| 70 | /* |
| 71 | * multipath_end_bh_io() is called when we have finished servicing a multipathed |
| 72 | * operation and are ready to return a success/failure code to the buffer |
| 73 | * cache layer. |
| 74 | */ |
| 75 | static void multipath_end_bh_io (struct multipath_bh *mp_bh, int err) |
| 76 | { |
| 77 | struct bio *bio = mp_bh->master_bio; |
| 78 | multipath_conf_t *conf = mddev_to_conf(mp_bh->mddev); |
| 79 | |
NeilBrown | 6712ecf | 2007-09-27 12:47:43 +0200 | [diff] [blame] | 80 | bio_endio(bio, err); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 81 | mempool_free(mp_bh, conf->pool); |
| 82 | } |
| 83 | |
NeilBrown | 6712ecf | 2007-09-27 12:47:43 +0200 | [diff] [blame] | 84 | static void multipath_end_request(struct bio *bio, int error) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 85 | { |
| 86 | int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags); |
| 87 | struct multipath_bh * mp_bh = (struct multipath_bh *)(bio->bi_private); |
| 88 | multipath_conf_t *conf = mddev_to_conf(mp_bh->mddev); |
| 89 | mdk_rdev_t *rdev = conf->multipaths[mp_bh->path].rdev; |
| 90 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 91 | if (uptodate) |
| 92 | multipath_end_bh_io(mp_bh, 0); |
| 93 | else if (!bio_rw_ahead(bio)) { |
| 94 | /* |
| 95 | * oops, IO error: |
| 96 | */ |
| 97 | char b[BDEVNAME_SIZE]; |
| 98 | md_error (mp_bh->mddev, rdev); |
| 99 | printk(KERN_ERR "multipath: %s: rescheduling sector %llu\n", |
| 100 | bdevname(rdev->bdev,b), |
| 101 | (unsigned long long)bio->bi_sector); |
| 102 | multipath_reschedule_retry(mp_bh); |
| 103 | } else |
| 104 | multipath_end_bh_io(mp_bh, error); |
| 105 | rdev_dec_pending(rdev, conf->mddev); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 106 | } |
| 107 | |
| 108 | static void unplug_slaves(mddev_t *mddev) |
| 109 | { |
| 110 | multipath_conf_t *conf = mddev_to_conf(mddev); |
| 111 | int i; |
| 112 | |
| 113 | rcu_read_lock(); |
| 114 | for (i=0; i<mddev->raid_disks; i++) { |
Suzanne Wood | d6065f7 | 2005-11-08 21:39:27 -0800 | [diff] [blame] | 115 | mdk_rdev_t *rdev = rcu_dereference(conf->multipaths[i].rdev); |
NeilBrown | b2d444d | 2005-11-08 21:39:31 -0800 | [diff] [blame] | 116 | if (rdev && !test_bit(Faulty, &rdev->flags) |
| 117 | && atomic_read(&rdev->nr_pending)) { |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 118 | struct request_queue *r_queue = bdev_get_queue(rdev->bdev); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 119 | |
| 120 | atomic_inc(&rdev->nr_pending); |
| 121 | rcu_read_unlock(); |
| 122 | |
Alan D. Brunelle | 2ad8b1e | 2007-11-07 14:26:56 -0500 | [diff] [blame] | 123 | blk_unplug(r_queue); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 124 | |
| 125 | rdev_dec_pending(rdev, mddev); |
| 126 | rcu_read_lock(); |
| 127 | } |
| 128 | } |
| 129 | rcu_read_unlock(); |
| 130 | } |
| 131 | |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 132 | static void multipath_unplug(struct request_queue *q) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 133 | { |
| 134 | unplug_slaves(q->queuedata); |
| 135 | } |
| 136 | |
| 137 | |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 138 | static int multipath_make_request (struct request_queue *q, struct bio * bio) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 139 | { |
| 140 | mddev_t *mddev = q->queuedata; |
| 141 | multipath_conf_t *conf = mddev_to_conf(mddev); |
| 142 | struct multipath_bh * mp_bh; |
| 143 | struct multipath_info *multipath; |
Jens Axboe | a362357 | 2005-11-01 09:26:16 +0100 | [diff] [blame] | 144 | const int rw = bio_data_dir(bio); |
Tejun Heo | c995905 | 2008-08-25 19:47:21 +0900 | [diff] [blame] | 145 | int cpu; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 146 | |
NeilBrown | e5dcdd8 | 2005-09-09 16:23:41 -0700 | [diff] [blame] | 147 | if (unlikely(bio_barrier(bio))) { |
NeilBrown | 6712ecf | 2007-09-27 12:47:43 +0200 | [diff] [blame] | 148 | bio_endio(bio, -EOPNOTSUPP); |
NeilBrown | e5dcdd8 | 2005-09-09 16:23:41 -0700 | [diff] [blame] | 149 | return 0; |
| 150 | } |
| 151 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 152 | mp_bh = mempool_alloc(conf->pool, GFP_NOIO); |
| 153 | |
| 154 | mp_bh->master_bio = bio; |
| 155 | mp_bh->mddev = mddev; |
| 156 | |
Tejun Heo | 074a7ac | 2008-08-25 19:56:14 +0900 | [diff] [blame] | 157 | cpu = part_stat_lock(); |
| 158 | part_stat_inc(cpu, &mddev->gendisk->part0, ios[rw]); |
| 159 | part_stat_add(cpu, &mddev->gendisk->part0, sectors[rw], |
| 160 | bio_sectors(bio)); |
| 161 | part_stat_unlock(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 162 | |
| 163 | mp_bh->path = multipath_map(conf); |
| 164 | if (mp_bh->path < 0) { |
NeilBrown | 6712ecf | 2007-09-27 12:47:43 +0200 | [diff] [blame] | 165 | bio_endio(bio, -EIO); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 166 | mempool_free(mp_bh, conf->pool); |
| 167 | return 0; |
| 168 | } |
| 169 | multipath = conf->multipaths + mp_bh->path; |
| 170 | |
| 171 | mp_bh->bio = *bio; |
| 172 | mp_bh->bio.bi_sector += multipath->rdev->data_offset; |
| 173 | mp_bh->bio.bi_bdev = multipath->rdev->bdev; |
Mike Christie | 6000a36 | 2008-08-19 18:45:30 -0500 | [diff] [blame] | 174 | mp_bh->bio.bi_rw |= (1 << BIO_RW_FAILFAST_TRANSPORT); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 175 | mp_bh->bio.bi_end_io = multipath_end_request; |
| 176 | mp_bh->bio.bi_private = mp_bh; |
| 177 | generic_make_request(&mp_bh->bio); |
| 178 | return 0; |
| 179 | } |
| 180 | |
| 181 | static void multipath_status (struct seq_file *seq, mddev_t *mddev) |
| 182 | { |
| 183 | multipath_conf_t *conf = mddev_to_conf(mddev); |
| 184 | int i; |
| 185 | |
| 186 | seq_printf (seq, " [%d/%d] [", conf->raid_disks, |
| 187 | conf->working_disks); |
| 188 | for (i = 0; i < conf->raid_disks; i++) |
| 189 | seq_printf (seq, "%s", |
| 190 | conf->multipaths[i].rdev && |
NeilBrown | b2d444d | 2005-11-08 21:39:31 -0800 | [diff] [blame] | 191 | test_bit(In_sync, &conf->multipaths[i].rdev->flags) ? "U" : "_"); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 192 | seq_printf (seq, "]"); |
| 193 | } |
| 194 | |
NeilBrown | 0d12922 | 2006-10-03 01:15:54 -0700 | [diff] [blame] | 195 | static int multipath_congested(void *data, int bits) |
| 196 | { |
| 197 | mddev_t *mddev = data; |
| 198 | multipath_conf_t *conf = mddev_to_conf(mddev); |
| 199 | int i, ret = 0; |
| 200 | |
| 201 | rcu_read_lock(); |
| 202 | for (i = 0; i < mddev->raid_disks ; i++) { |
| 203 | mdk_rdev_t *rdev = rcu_dereference(conf->multipaths[i].rdev); |
| 204 | if (rdev && !test_bit(Faulty, &rdev->flags)) { |
Jens Axboe | 165125e | 2007-07-24 09:28:11 +0200 | [diff] [blame] | 205 | struct request_queue *q = bdev_get_queue(rdev->bdev); |
NeilBrown | 0d12922 | 2006-10-03 01:15:54 -0700 | [diff] [blame] | 206 | |
| 207 | ret |= bdi_congested(&q->backing_dev_info, bits); |
| 208 | /* Just like multipath_map, we just check the |
| 209 | * first available device |
| 210 | */ |
| 211 | break; |
| 212 | } |
| 213 | } |
| 214 | rcu_read_unlock(); |
| 215 | return ret; |
| 216 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 217 | |
| 218 | /* |
| 219 | * Careful, this can execute in IRQ contexts as well! |
| 220 | */ |
| 221 | static void multipath_error (mddev_t *mddev, mdk_rdev_t *rdev) |
| 222 | { |
| 223 | multipath_conf_t *conf = mddev_to_conf(mddev); |
| 224 | |
| 225 | if (conf->working_disks <= 1) { |
| 226 | /* |
| 227 | * Uh oh, we can do nothing if this is our last path, but |
| 228 | * first check if this is a queued request for a device |
| 229 | * which has just failed. |
| 230 | */ |
| 231 | printk(KERN_ALERT |
| 232 | "multipath: only one IO path left and IO error.\n"); |
| 233 | /* leave it active... it's all we have */ |
| 234 | } else { |
| 235 | /* |
| 236 | * Mark disk as unusable |
| 237 | */ |
NeilBrown | b2d444d | 2005-11-08 21:39:31 -0800 | [diff] [blame] | 238 | if (!test_bit(Faulty, &rdev->flags)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 239 | char b[BDEVNAME_SIZE]; |
NeilBrown | b2d444d | 2005-11-08 21:39:31 -0800 | [diff] [blame] | 240 | clear_bit(In_sync, &rdev->flags); |
| 241 | set_bit(Faulty, &rdev->flags); |
NeilBrown | 850b2b4 | 2006-10-03 01:15:46 -0700 | [diff] [blame] | 242 | set_bit(MD_CHANGE_DEVS, &mddev->flags); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 243 | conf->working_disks--; |
NeilBrown | 750a8f3 | 2006-10-28 10:38:31 -0700 | [diff] [blame] | 244 | mddev->degraded++; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 245 | printk(KERN_ALERT "multipath: IO failure on %s," |
Nick Andrew | d7a420c | 2008-04-28 02:15:55 -0700 | [diff] [blame] | 246 | " disabling IO path.\n" |
| 247 | "multipath: Operation continuing" |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 248 | " on %d IO paths.\n", |
| 249 | bdevname (rdev->bdev,b), |
| 250 | conf->working_disks); |
| 251 | } |
| 252 | } |
| 253 | } |
| 254 | |
| 255 | static void print_multipath_conf (multipath_conf_t *conf) |
| 256 | { |
| 257 | int i; |
| 258 | struct multipath_info *tmp; |
| 259 | |
| 260 | printk("MULTIPATH conf printout:\n"); |
| 261 | if (!conf) { |
| 262 | printk("(conf==NULL)\n"); |
| 263 | return; |
| 264 | } |
| 265 | printk(" --- wd:%d rd:%d\n", conf->working_disks, |
| 266 | conf->raid_disks); |
| 267 | |
| 268 | for (i = 0; i < conf->raid_disks; i++) { |
| 269 | char b[BDEVNAME_SIZE]; |
| 270 | tmp = conf->multipaths + i; |
| 271 | if (tmp->rdev) |
| 272 | printk(" disk%d, o:%d, dev:%s\n", |
NeilBrown | b2d444d | 2005-11-08 21:39:31 -0800 | [diff] [blame] | 273 | i,!test_bit(Faulty, &tmp->rdev->flags), |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 274 | bdevname(tmp->rdev->bdev,b)); |
| 275 | } |
| 276 | } |
| 277 | |
| 278 | |
| 279 | static int multipath_add_disk(mddev_t *mddev, mdk_rdev_t *rdev) |
| 280 | { |
| 281 | multipath_conf_t *conf = mddev->private; |
Jesper Juhl | 352d768 | 2006-01-09 20:54:44 -0800 | [diff] [blame] | 282 | struct request_queue *q; |
Neil Brown | 199050e | 2008-06-28 08:31:33 +1000 | [diff] [blame] | 283 | int err = -EEXIST; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 284 | int path; |
| 285 | struct multipath_info *p; |
Neil Brown | 6c2fce2 | 2008-06-28 08:31:31 +1000 | [diff] [blame] | 286 | int first = 0; |
| 287 | int last = mddev->raid_disks - 1; |
| 288 | |
| 289 | if (rdev->raid_disk >= 0) |
| 290 | first = last = rdev->raid_disk; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 291 | |
| 292 | print_multipath_conf(conf); |
| 293 | |
Neil Brown | 6c2fce2 | 2008-06-28 08:31:31 +1000 | [diff] [blame] | 294 | for (path = first; path <= last; path++) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 295 | if ((p=conf->multipaths+path)->rdev == NULL) { |
Jesper Juhl | 352d768 | 2006-01-09 20:54:44 -0800 | [diff] [blame] | 296 | q = rdev->bdev->bd_disk->queue; |
| 297 | blk_queue_stack_limits(mddev->queue, q); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 298 | |
| 299 | /* as we don't honour merge_bvec_fn, we must never risk |
| 300 | * violating it, so limit ->max_sector to one PAGE, as |
| 301 | * a one page request is never in violation. |
| 302 | * (Note: it is very unlikely that a device with |
| 303 | * merge_bvec_fn will be involved in multipath.) |
| 304 | */ |
Jesper Juhl | 352d768 | 2006-01-09 20:54:44 -0800 | [diff] [blame] | 305 | if (q->merge_bvec_fn && |
Martin K. Petersen | ae03bf6 | 2009-05-22 17:17:50 -0400 | [diff] [blame] | 306 | queue_max_sectors(q) > (PAGE_SIZE>>9)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 307 | blk_queue_max_sectors(mddev->queue, PAGE_SIZE>>9); |
| 308 | |
| 309 | conf->working_disks++; |
NeilBrown | 750a8f3 | 2006-10-28 10:38:31 -0700 | [diff] [blame] | 310 | mddev->degraded--; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 311 | rdev->raid_disk = path; |
NeilBrown | b2d444d | 2005-11-08 21:39:31 -0800 | [diff] [blame] | 312 | set_bit(In_sync, &rdev->flags); |
Suzanne Wood | d6065f7 | 2005-11-08 21:39:27 -0800 | [diff] [blame] | 313 | rcu_assign_pointer(p->rdev, rdev); |
Neil Brown | 199050e | 2008-06-28 08:31:33 +1000 | [diff] [blame] | 314 | err = 0; |
| 315 | break; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 316 | } |
| 317 | |
| 318 | print_multipath_conf(conf); |
Neil Brown | 199050e | 2008-06-28 08:31:33 +1000 | [diff] [blame] | 319 | |
| 320 | return err; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 321 | } |
| 322 | |
| 323 | static int multipath_remove_disk(mddev_t *mddev, int number) |
| 324 | { |
| 325 | multipath_conf_t *conf = mddev->private; |
| 326 | int err = 0; |
| 327 | mdk_rdev_t *rdev; |
| 328 | struct multipath_info *p = conf->multipaths + number; |
| 329 | |
| 330 | print_multipath_conf(conf); |
| 331 | |
| 332 | rdev = p->rdev; |
| 333 | if (rdev) { |
NeilBrown | b2d444d | 2005-11-08 21:39:31 -0800 | [diff] [blame] | 334 | if (test_bit(In_sync, &rdev->flags) || |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 335 | atomic_read(&rdev->nr_pending)) { |
NeilBrown | dfc7064 | 2008-05-23 13:04:39 -0700 | [diff] [blame] | 336 | printk(KERN_ERR "hot-remove-disk, slot %d is identified" |
| 337 | " but is still operational!\n", number); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 338 | err = -EBUSY; |
| 339 | goto abort; |
| 340 | } |
| 341 | p->rdev = NULL; |
Paul E. McKenney | fbd568a3e | 2005-05-01 08:59:04 -0700 | [diff] [blame] | 342 | synchronize_rcu(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 343 | if (atomic_read(&rdev->nr_pending)) { |
| 344 | /* lost the race, try later */ |
| 345 | err = -EBUSY; |
| 346 | p->rdev = rdev; |
| 347 | } |
| 348 | } |
| 349 | abort: |
| 350 | |
| 351 | print_multipath_conf(conf); |
| 352 | return err; |
| 353 | } |
| 354 | |
| 355 | |
| 356 | |
| 357 | /* |
| 358 | * This is a kernel thread which: |
| 359 | * |
| 360 | * 1. Retries failed read operations on working multipaths. |
| 361 | * 2. Updates the raid superblock when problems encounter. |
| 362 | * 3. Performs writes following reads for array syncronising. |
| 363 | */ |
| 364 | |
| 365 | static void multipathd (mddev_t *mddev) |
| 366 | { |
| 367 | struct multipath_bh *mp_bh; |
| 368 | struct bio *bio; |
| 369 | unsigned long flags; |
| 370 | multipath_conf_t *conf = mddev_to_conf(mddev); |
| 371 | struct list_head *head = &conf->retry_list; |
| 372 | |
| 373 | md_check_recovery(mddev); |
| 374 | for (;;) { |
| 375 | char b[BDEVNAME_SIZE]; |
| 376 | spin_lock_irqsave(&conf->device_lock, flags); |
| 377 | if (list_empty(head)) |
| 378 | break; |
| 379 | mp_bh = list_entry(head->prev, struct multipath_bh, retry_list); |
| 380 | list_del(head->prev); |
| 381 | spin_unlock_irqrestore(&conf->device_lock, flags); |
| 382 | |
| 383 | bio = &mp_bh->bio; |
| 384 | bio->bi_sector = mp_bh->master_bio->bi_sector; |
| 385 | |
| 386 | if ((mp_bh->path = multipath_map (conf))<0) { |
| 387 | printk(KERN_ALERT "multipath: %s: unrecoverable IO read" |
| 388 | " error for block %llu\n", |
| 389 | bdevname(bio->bi_bdev,b), |
| 390 | (unsigned long long)bio->bi_sector); |
| 391 | multipath_end_bh_io(mp_bh, -EIO); |
| 392 | } else { |
| 393 | printk(KERN_ERR "multipath: %s: redirecting sector %llu" |
| 394 | " to another IO path\n", |
| 395 | bdevname(bio->bi_bdev,b), |
| 396 | (unsigned long long)bio->bi_sector); |
| 397 | *bio = *(mp_bh->master_bio); |
| 398 | bio->bi_sector += conf->multipaths[mp_bh->path].rdev->data_offset; |
| 399 | bio->bi_bdev = conf->multipaths[mp_bh->path].rdev->bdev; |
Mike Christie | 6000a36 | 2008-08-19 18:45:30 -0500 | [diff] [blame] | 400 | bio->bi_rw |= (1 << BIO_RW_FAILFAST_TRANSPORT); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 401 | bio->bi_end_io = multipath_end_request; |
| 402 | bio->bi_private = mp_bh; |
| 403 | generic_make_request(bio); |
| 404 | } |
| 405 | } |
| 406 | spin_unlock_irqrestore(&conf->device_lock, flags); |
| 407 | } |
| 408 | |
Dan Williams | 80c3a6c | 2009-03-17 18:10:40 -0700 | [diff] [blame] | 409 | static sector_t multipath_size(mddev_t *mddev, sector_t sectors, int raid_disks) |
| 410 | { |
| 411 | WARN_ONCE(sectors || raid_disks, |
| 412 | "%s does not support generic reshape\n", __func__); |
| 413 | |
| 414 | return mddev->dev_sectors; |
| 415 | } |
| 416 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 417 | static int multipath_run (mddev_t *mddev) |
| 418 | { |
| 419 | multipath_conf_t *conf; |
| 420 | int disk_idx; |
| 421 | struct multipath_info *disk; |
| 422 | mdk_rdev_t *rdev; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 423 | |
| 424 | if (mddev->level != LEVEL_MULTIPATH) { |
| 425 | printk("multipath: %s: raid level not set to multipath IO (%d)\n", |
| 426 | mdname(mddev), mddev->level); |
| 427 | goto out; |
| 428 | } |
| 429 | /* |
| 430 | * copy the already verified devices into our private MULTIPATH |
| 431 | * bookkeeping area. [whatever we allocate in multipath_run(), |
| 432 | * should be freed in multipath_stop()] |
| 433 | */ |
Neil Brown | e7e72bf | 2008-05-14 16:05:54 -0700 | [diff] [blame] | 434 | mddev->queue->queue_lock = &mddev->queue->__queue_lock; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 435 | |
NeilBrown | 9ffae0c | 2006-01-06 00:20:32 -0800 | [diff] [blame] | 436 | conf = kzalloc(sizeof(multipath_conf_t), GFP_KERNEL); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 437 | mddev->private = conf; |
| 438 | if (!conf) { |
| 439 | printk(KERN_ERR |
| 440 | "multipath: couldn't allocate memory for %s\n", |
| 441 | mdname(mddev)); |
| 442 | goto out; |
| 443 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 444 | |
NeilBrown | 9ffae0c | 2006-01-06 00:20:32 -0800 | [diff] [blame] | 445 | conf->multipaths = kzalloc(sizeof(struct multipath_info)*mddev->raid_disks, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 446 | GFP_KERNEL); |
| 447 | if (!conf->multipaths) { |
| 448 | printk(KERN_ERR |
| 449 | "multipath: couldn't allocate memory for %s\n", |
| 450 | mdname(mddev)); |
| 451 | goto out_free_conf; |
| 452 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 453 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 454 | conf->working_disks = 0; |
Cheng Renquan | 159ec1f | 2009-01-09 08:31:08 +1100 | [diff] [blame] | 455 | list_for_each_entry(rdev, &mddev->disks, same_set) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 456 | disk_idx = rdev->raid_disk; |
| 457 | if (disk_idx < 0 || |
| 458 | disk_idx >= mddev->raid_disks) |
| 459 | continue; |
| 460 | |
| 461 | disk = conf->multipaths + disk_idx; |
| 462 | disk->rdev = rdev; |
| 463 | |
| 464 | blk_queue_stack_limits(mddev->queue, |
| 465 | rdev->bdev->bd_disk->queue); |
| 466 | /* as we don't honour merge_bvec_fn, we must never risk |
| 467 | * violating it, not that we ever expect a device with |
| 468 | * a merge_bvec_fn to be involved in multipath */ |
| 469 | if (rdev->bdev->bd_disk->queue->merge_bvec_fn && |
Martin K. Petersen | ae03bf6 | 2009-05-22 17:17:50 -0400 | [diff] [blame] | 470 | queue_max_sectors(mddev->queue) > (PAGE_SIZE>>9)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 471 | blk_queue_max_sectors(mddev->queue, PAGE_SIZE>>9); |
| 472 | |
NeilBrown | b2d444d | 2005-11-08 21:39:31 -0800 | [diff] [blame] | 473 | if (!test_bit(Faulty, &rdev->flags)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 474 | conf->working_disks++; |
| 475 | } |
| 476 | |
| 477 | conf->raid_disks = mddev->raid_disks; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 478 | conf->mddev = mddev; |
| 479 | spin_lock_init(&conf->device_lock); |
| 480 | INIT_LIST_HEAD(&conf->retry_list); |
| 481 | |
| 482 | if (!conf->working_disks) { |
| 483 | printk(KERN_ERR "multipath: no operational IO paths for %s\n", |
| 484 | mdname(mddev)); |
| 485 | goto out_free_conf; |
| 486 | } |
NeilBrown | 2e333e8 | 2006-10-21 10:24:07 -0700 | [diff] [blame] | 487 | mddev->degraded = conf->raid_disks - conf->working_disks; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 488 | |
Matthew Dobson | 26b6e05 | 2006-03-26 01:37:48 -0800 | [diff] [blame] | 489 | conf->pool = mempool_create_kzalloc_pool(NR_RESERVED_BUFS, |
| 490 | sizeof(struct multipath_bh)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 491 | if (conf->pool == NULL) { |
| 492 | printk(KERN_ERR |
| 493 | "multipath: couldn't allocate memory for %s\n", |
| 494 | mdname(mddev)); |
| 495 | goto out_free_conf; |
| 496 | } |
| 497 | |
| 498 | { |
| 499 | mddev->thread = md_register_thread(multipathd, mddev, "%s_multipath"); |
| 500 | if (!mddev->thread) { |
| 501 | printk(KERN_ERR "multipath: couldn't allocate thread" |
| 502 | " for %s\n", mdname(mddev)); |
| 503 | goto out_free_conf; |
| 504 | } |
| 505 | } |
| 506 | |
| 507 | printk(KERN_INFO |
| 508 | "multipath: array %s active with %d out of %d IO paths\n", |
| 509 | mdname(mddev), conf->working_disks, mddev->raid_disks); |
| 510 | /* |
| 511 | * Ok, everything is just fine now |
| 512 | */ |
Dan Williams | 1f40362 | 2009-03-31 14:59:03 +1100 | [diff] [blame] | 513 | md_set_array_sectors(mddev, multipath_size(mddev, 0, 0)); |
NeilBrown | 7a5febe | 2005-05-16 21:53:16 -0700 | [diff] [blame] | 514 | |
| 515 | mddev->queue->unplug_fn = multipath_unplug; |
NeilBrown | 0d12922 | 2006-10-03 01:15:54 -0700 | [diff] [blame] | 516 | mddev->queue->backing_dev_info.congested_fn = multipath_congested; |
| 517 | mddev->queue->backing_dev_info.congested_data = mddev; |
NeilBrown | 7a5febe | 2005-05-16 21:53:16 -0700 | [diff] [blame] | 518 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 519 | return 0; |
| 520 | |
| 521 | out_free_conf: |
| 522 | if (conf->pool) |
| 523 | mempool_destroy(conf->pool); |
Jesper Juhl | 990a8ba | 2005-06-21 17:17:30 -0700 | [diff] [blame] | 524 | kfree(conf->multipaths); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 525 | kfree(conf); |
| 526 | mddev->private = NULL; |
| 527 | out: |
| 528 | return -EIO; |
| 529 | } |
| 530 | |
| 531 | |
| 532 | static int multipath_stop (mddev_t *mddev) |
| 533 | { |
| 534 | multipath_conf_t *conf = mddev_to_conf(mddev); |
| 535 | |
| 536 | md_unregister_thread(mddev->thread); |
| 537 | mddev->thread = NULL; |
| 538 | blk_sync_queue(mddev->queue); /* the unplug fn references 'conf'*/ |
| 539 | mempool_destroy(conf->pool); |
| 540 | kfree(conf->multipaths); |
| 541 | kfree(conf); |
| 542 | mddev->private = NULL; |
| 543 | return 0; |
| 544 | } |
| 545 | |
NeilBrown | 2604b70 | 2006-01-06 00:20:36 -0800 | [diff] [blame] | 546 | static struct mdk_personality multipath_personality = |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 547 | { |
| 548 | .name = "multipath", |
NeilBrown | 2604b70 | 2006-01-06 00:20:36 -0800 | [diff] [blame] | 549 | .level = LEVEL_MULTIPATH, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 550 | .owner = THIS_MODULE, |
| 551 | .make_request = multipath_make_request, |
| 552 | .run = multipath_run, |
| 553 | .stop = multipath_stop, |
| 554 | .status = multipath_status, |
| 555 | .error_handler = multipath_error, |
| 556 | .hot_add_disk = multipath_add_disk, |
| 557 | .hot_remove_disk= multipath_remove_disk, |
Dan Williams | 80c3a6c | 2009-03-17 18:10:40 -0700 | [diff] [blame] | 558 | .size = multipath_size, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 559 | }; |
| 560 | |
| 561 | static int __init multipath_init (void) |
| 562 | { |
NeilBrown | 2604b70 | 2006-01-06 00:20:36 -0800 | [diff] [blame] | 563 | return register_md_personality (&multipath_personality); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 564 | } |
| 565 | |
| 566 | static void __exit multipath_exit (void) |
| 567 | { |
NeilBrown | 2604b70 | 2006-01-06 00:20:36 -0800 | [diff] [blame] | 568 | unregister_md_personality (&multipath_personality); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 569 | } |
| 570 | |
| 571 | module_init(multipath_init); |
| 572 | module_exit(multipath_exit); |
| 573 | MODULE_LICENSE("GPL"); |
| 574 | MODULE_ALIAS("md-personality-7"); /* MULTIPATH */ |
NeilBrown | d9d166c | 2006-01-06 00:20:51 -0800 | [diff] [blame] | 575 | MODULE_ALIAS("md-multipath"); |
NeilBrown | 2604b70 | 2006-01-06 00:20:36 -0800 | [diff] [blame] | 576 | MODULE_ALIAS("md-level--4"); |