blob: e968116e0de9699d2bef0f114ae79f638506bf1c [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
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
22#include <linux/module.h>
23#include <linux/slab.h>
24#include <linux/spinlock.h>
25#include <linux/raid/multipath.h>
26#include <linux/buffer_head.h>
27#include <asm/atomic.h>
28
29#define MAJOR_NR MD_MAJOR
30#define MD_DRIVER
31#define MD_PERSONALITY
32
33#define MAX_WORK_PER_DISK 128
34
35#define NR_RESERVED_BUFS 32
36
37
Linus Torvalds1da177e2005-04-16 15:20:36 -070038static int multipath_map (multipath_conf_t *conf)
39{
40 int i, disks = conf->raid_disks;
41
42 /*
43 * Later we do read balancing on the read side
44 * now we use the first available disk.
45 */
46
47 rcu_read_lock();
48 for (i = 0; i < disks; i++) {
Suzanne Woodd6065f72005-11-08 21:39:27 -080049 mdk_rdev_t *rdev = rcu_dereference(conf->multipaths[i].rdev);
NeilBrownb2d444d2005-11-08 21:39:31 -080050 if (rdev && test_bit(In_sync, &rdev->flags)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -070051 atomic_inc(&rdev->nr_pending);
52 rcu_read_unlock();
53 return i;
54 }
55 }
56 rcu_read_unlock();
57
58 printk(KERN_ERR "multipath_map(): no more operational IO paths?\n");
59 return (-1);
60}
61
62static void multipath_reschedule_retry (struct multipath_bh *mp_bh)
63{
64 unsigned long flags;
65 mddev_t *mddev = mp_bh->mddev;
66 multipath_conf_t *conf = mddev_to_conf(mddev);
67
68 spin_lock_irqsave(&conf->device_lock, flags);
69 list_add(&mp_bh->retry_list, &conf->retry_list);
70 spin_unlock_irqrestore(&conf->device_lock, flags);
71 md_wakeup_thread(mddev->thread);
72}
73
74
75/*
76 * multipath_end_bh_io() is called when we have finished servicing a multipathed
77 * operation and are ready to return a success/failure code to the buffer
78 * cache layer.
79 */
80static void multipath_end_bh_io (struct multipath_bh *mp_bh, int err)
81{
82 struct bio *bio = mp_bh->master_bio;
83 multipath_conf_t *conf = mddev_to_conf(mp_bh->mddev);
84
NeilBrown6712ecf2007-09-27 12:47:43 +020085 bio_endio(bio, err);
Linus Torvalds1da177e2005-04-16 15:20:36 -070086 mempool_free(mp_bh, conf->pool);
87}
88
NeilBrown6712ecf2007-09-27 12:47:43 +020089static void multipath_end_request(struct bio *bio, int error)
Linus Torvalds1da177e2005-04-16 15:20:36 -070090{
91 int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
92 struct multipath_bh * mp_bh = (struct multipath_bh *)(bio->bi_private);
93 multipath_conf_t *conf = mddev_to_conf(mp_bh->mddev);
94 mdk_rdev_t *rdev = conf->multipaths[mp_bh->path].rdev;
95
Linus Torvalds1da177e2005-04-16 15:20:36 -070096 if (uptodate)
97 multipath_end_bh_io(mp_bh, 0);
98 else if (!bio_rw_ahead(bio)) {
99 /*
100 * oops, IO error:
101 */
102 char b[BDEVNAME_SIZE];
103 md_error (mp_bh->mddev, rdev);
104 printk(KERN_ERR "multipath: %s: rescheduling sector %llu\n",
105 bdevname(rdev->bdev,b),
106 (unsigned long long)bio->bi_sector);
107 multipath_reschedule_retry(mp_bh);
108 } else
109 multipath_end_bh_io(mp_bh, error);
110 rdev_dec_pending(rdev, conf->mddev);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700111}
112
113static void unplug_slaves(mddev_t *mddev)
114{
115 multipath_conf_t *conf = mddev_to_conf(mddev);
116 int i;
117
118 rcu_read_lock();
119 for (i=0; i<mddev->raid_disks; i++) {
Suzanne Woodd6065f72005-11-08 21:39:27 -0800120 mdk_rdev_t *rdev = rcu_dereference(conf->multipaths[i].rdev);
NeilBrownb2d444d2005-11-08 21:39:31 -0800121 if (rdev && !test_bit(Faulty, &rdev->flags)
122 && atomic_read(&rdev->nr_pending)) {
Jens Axboe165125e2007-07-24 09:28:11 +0200123 struct request_queue *r_queue = bdev_get_queue(rdev->bdev);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700124
125 atomic_inc(&rdev->nr_pending);
126 rcu_read_unlock();
127
Alan D. Brunelle2ad8b1e2007-11-07 14:26:56 -0500128 blk_unplug(r_queue);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700129
130 rdev_dec_pending(rdev, mddev);
131 rcu_read_lock();
132 }
133 }
134 rcu_read_unlock();
135}
136
Jens Axboe165125e2007-07-24 09:28:11 +0200137static void multipath_unplug(struct request_queue *q)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700138{
139 unplug_slaves(q->queuedata);
140}
141
142
Jens Axboe165125e2007-07-24 09:28:11 +0200143static int multipath_make_request (struct request_queue *q, struct bio * bio)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700144{
145 mddev_t *mddev = q->queuedata;
146 multipath_conf_t *conf = mddev_to_conf(mddev);
147 struct multipath_bh * mp_bh;
148 struct multipath_info *multipath;
Jens Axboea3623572005-11-01 09:26:16 +0100149 const int rw = bio_data_dir(bio);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700150
NeilBrowne5dcdd82005-09-09 16:23:41 -0700151 if (unlikely(bio_barrier(bio))) {
NeilBrown6712ecf2007-09-27 12:47:43 +0200152 bio_endio(bio, -EOPNOTSUPP);
NeilBrowne5dcdd82005-09-09 16:23:41 -0700153 return 0;
154 }
155
Linus Torvalds1da177e2005-04-16 15:20:36 -0700156 mp_bh = mempool_alloc(conf->pool, GFP_NOIO);
157
158 mp_bh->master_bio = bio;
159 mp_bh->mddev = mddev;
160
Jens Axboea3623572005-11-01 09:26:16 +0100161 disk_stat_inc(mddev->gendisk, ios[rw]);
162 disk_stat_add(mddev->gendisk, sectors[rw], bio_sectors(bio));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700163
164 mp_bh->path = multipath_map(conf);
165 if (mp_bh->path < 0) {
NeilBrown6712ecf2007-09-27 12:47:43 +0200166 bio_endio(bio, -EIO);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700167 mempool_free(mp_bh, conf->pool);
168 return 0;
169 }
170 multipath = conf->multipaths + mp_bh->path;
171
172 mp_bh->bio = *bio;
173 mp_bh->bio.bi_sector += multipath->rdev->data_offset;
174 mp_bh->bio.bi_bdev = multipath->rdev->bdev;
175 mp_bh->bio.bi_rw |= (1 << BIO_RW_FAILFAST);
176 mp_bh->bio.bi_end_io = multipath_end_request;
177 mp_bh->bio.bi_private = mp_bh;
178 generic_make_request(&mp_bh->bio);
179 return 0;
180}
181
182static void multipath_status (struct seq_file *seq, mddev_t *mddev)
183{
184 multipath_conf_t *conf = mddev_to_conf(mddev);
185 int i;
186
187 seq_printf (seq, " [%d/%d] [", conf->raid_disks,
188 conf->working_disks);
189 for (i = 0; i < conf->raid_disks; i++)
190 seq_printf (seq, "%s",
191 conf->multipaths[i].rdev &&
NeilBrownb2d444d2005-11-08 21:39:31 -0800192 test_bit(In_sync, &conf->multipaths[i].rdev->flags) ? "U" : "_");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700193 seq_printf (seq, "]");
194}
195
NeilBrown0d129222006-10-03 01:15:54 -0700196static int multipath_congested(void *data, int bits)
197{
198 mddev_t *mddev = data;
199 multipath_conf_t *conf = mddev_to_conf(mddev);
200 int i, ret = 0;
201
202 rcu_read_lock();
203 for (i = 0; i < mddev->raid_disks ; i++) {
204 mdk_rdev_t *rdev = rcu_dereference(conf->multipaths[i].rdev);
205 if (rdev && !test_bit(Faulty, &rdev->flags)) {
Jens Axboe165125e2007-07-24 09:28:11 +0200206 struct request_queue *q = bdev_get_queue(rdev->bdev);
NeilBrown0d129222006-10-03 01:15:54 -0700207
208 ret |= bdi_congested(&q->backing_dev_info, bits);
209 /* Just like multipath_map, we just check the
210 * first available device
211 */
212 break;
213 }
214 }
215 rcu_read_unlock();
216 return ret;
217}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700218
219/*
220 * Careful, this can execute in IRQ contexts as well!
221 */
222static void multipath_error (mddev_t *mddev, mdk_rdev_t *rdev)
223{
224 multipath_conf_t *conf = mddev_to_conf(mddev);
225
226 if (conf->working_disks <= 1) {
227 /*
228 * Uh oh, we can do nothing if this is our last path, but
229 * first check if this is a queued request for a device
230 * which has just failed.
231 */
232 printk(KERN_ALERT
233 "multipath: only one IO path left and IO error.\n");
234 /* leave it active... it's all we have */
235 } else {
236 /*
237 * Mark disk as unusable
238 */
NeilBrownb2d444d2005-11-08 21:39:31 -0800239 if (!test_bit(Faulty, &rdev->flags)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700240 char b[BDEVNAME_SIZE];
NeilBrownb2d444d2005-11-08 21:39:31 -0800241 clear_bit(In_sync, &rdev->flags);
242 set_bit(Faulty, &rdev->flags);
NeilBrown850b2b42006-10-03 01:15:46 -0700243 set_bit(MD_CHANGE_DEVS, &mddev->flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700244 conf->working_disks--;
NeilBrown750a8f32006-10-28 10:38:31 -0700245 mddev->degraded++;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700246 printk(KERN_ALERT "multipath: IO failure on %s,"
Nick Andrewd7a420c2008-04-28 02:15:55 -0700247 " disabling IO path.\n"
248 "multipath: Operation continuing"
Linus Torvalds1da177e2005-04-16 15:20:36 -0700249 " on %d IO paths.\n",
250 bdevname (rdev->bdev,b),
251 conf->working_disks);
252 }
253 }
254}
255
256static void print_multipath_conf (multipath_conf_t *conf)
257{
258 int i;
259 struct multipath_info *tmp;
260
261 printk("MULTIPATH conf printout:\n");
262 if (!conf) {
263 printk("(conf==NULL)\n");
264 return;
265 }
266 printk(" --- wd:%d rd:%d\n", conf->working_disks,
267 conf->raid_disks);
268
269 for (i = 0; i < conf->raid_disks; i++) {
270 char b[BDEVNAME_SIZE];
271 tmp = conf->multipaths + i;
272 if (tmp->rdev)
273 printk(" disk%d, o:%d, dev:%s\n",
NeilBrownb2d444d2005-11-08 21:39:31 -0800274 i,!test_bit(Faulty, &tmp->rdev->flags),
Linus Torvalds1da177e2005-04-16 15:20:36 -0700275 bdevname(tmp->rdev->bdev,b));
276 }
277}
278
279
280static int multipath_add_disk(mddev_t *mddev, mdk_rdev_t *rdev)
281{
282 multipath_conf_t *conf = mddev->private;
Jesper Juhl352d7682006-01-09 20:54:44 -0800283 struct request_queue *q;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700284 int found = 0;
285 int path;
286 struct multipath_info *p;
287
288 print_multipath_conf(conf);
289
290 for (path=0; path<mddev->raid_disks; path++)
291 if ((p=conf->multipaths+path)->rdev == NULL) {
Jesper Juhl352d7682006-01-09 20:54:44 -0800292 q = rdev->bdev->bd_disk->queue;
293 blk_queue_stack_limits(mddev->queue, q);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700294
295 /* as we don't honour merge_bvec_fn, we must never risk
296 * violating it, so limit ->max_sector to one PAGE, as
297 * a one page request is never in violation.
298 * (Note: it is very unlikely that a device with
299 * merge_bvec_fn will be involved in multipath.)
300 */
Jesper Juhl352d7682006-01-09 20:54:44 -0800301 if (q->merge_bvec_fn &&
Linus Torvalds1da177e2005-04-16 15:20:36 -0700302 mddev->queue->max_sectors > (PAGE_SIZE>>9))
303 blk_queue_max_sectors(mddev->queue, PAGE_SIZE>>9);
304
305 conf->working_disks++;
NeilBrown750a8f32006-10-28 10:38:31 -0700306 mddev->degraded--;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700307 rdev->raid_disk = path;
NeilBrownb2d444d2005-11-08 21:39:31 -0800308 set_bit(In_sync, &rdev->flags);
Suzanne Woodd6065f72005-11-08 21:39:27 -0800309 rcu_assign_pointer(p->rdev, rdev);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700310 found = 1;
311 }
312
313 print_multipath_conf(conf);
314 return found;
315}
316
317static int multipath_remove_disk(mddev_t *mddev, int number)
318{
319 multipath_conf_t *conf = mddev->private;
320 int err = 0;
321 mdk_rdev_t *rdev;
322 struct multipath_info *p = conf->multipaths + number;
323
324 print_multipath_conf(conf);
325
326 rdev = p->rdev;
327 if (rdev) {
NeilBrownb2d444d2005-11-08 21:39:31 -0800328 if (test_bit(In_sync, &rdev->flags) ||
Linus Torvalds1da177e2005-04-16 15:20:36 -0700329 atomic_read(&rdev->nr_pending)) {
NeilBrowndfc70642008-05-23 13:04:39 -0700330 printk(KERN_ERR "hot-remove-disk, slot %d is identified"
331 " but is still operational!\n", number);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700332 err = -EBUSY;
333 goto abort;
334 }
335 p->rdev = NULL;
Paul E. McKenneyfbd568a3e2005-05-01 08:59:04 -0700336 synchronize_rcu();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700337 if (atomic_read(&rdev->nr_pending)) {
338 /* lost the race, try later */
339 err = -EBUSY;
340 p->rdev = rdev;
341 }
342 }
343abort:
344
345 print_multipath_conf(conf);
346 return err;
347}
348
349
350
351/*
352 * This is a kernel thread which:
353 *
354 * 1. Retries failed read operations on working multipaths.
355 * 2. Updates the raid superblock when problems encounter.
356 * 3. Performs writes following reads for array syncronising.
357 */
358
359static void multipathd (mddev_t *mddev)
360{
361 struct multipath_bh *mp_bh;
362 struct bio *bio;
363 unsigned long flags;
364 multipath_conf_t *conf = mddev_to_conf(mddev);
365 struct list_head *head = &conf->retry_list;
366
367 md_check_recovery(mddev);
368 for (;;) {
369 char b[BDEVNAME_SIZE];
370 spin_lock_irqsave(&conf->device_lock, flags);
371 if (list_empty(head))
372 break;
373 mp_bh = list_entry(head->prev, struct multipath_bh, retry_list);
374 list_del(head->prev);
375 spin_unlock_irqrestore(&conf->device_lock, flags);
376
377 bio = &mp_bh->bio;
378 bio->bi_sector = mp_bh->master_bio->bi_sector;
379
380 if ((mp_bh->path = multipath_map (conf))<0) {
381 printk(KERN_ALERT "multipath: %s: unrecoverable IO read"
382 " error for block %llu\n",
383 bdevname(bio->bi_bdev,b),
384 (unsigned long long)bio->bi_sector);
385 multipath_end_bh_io(mp_bh, -EIO);
386 } else {
387 printk(KERN_ERR "multipath: %s: redirecting sector %llu"
388 " to another IO path\n",
389 bdevname(bio->bi_bdev,b),
390 (unsigned long long)bio->bi_sector);
391 *bio = *(mp_bh->master_bio);
392 bio->bi_sector += conf->multipaths[mp_bh->path].rdev->data_offset;
393 bio->bi_bdev = conf->multipaths[mp_bh->path].rdev->bdev;
394 bio->bi_rw |= (1 << BIO_RW_FAILFAST);
395 bio->bi_end_io = multipath_end_request;
396 bio->bi_private = mp_bh;
397 generic_make_request(bio);
398 }
399 }
400 spin_unlock_irqrestore(&conf->device_lock, flags);
401}
402
403static int multipath_run (mddev_t *mddev)
404{
405 multipath_conf_t *conf;
406 int disk_idx;
407 struct multipath_info *disk;
408 mdk_rdev_t *rdev;
409 struct list_head *tmp;
410
411 if (mddev->level != LEVEL_MULTIPATH) {
412 printk("multipath: %s: raid level not set to multipath IO (%d)\n",
413 mdname(mddev), mddev->level);
414 goto out;
415 }
416 /*
417 * copy the already verified devices into our private MULTIPATH
418 * bookkeeping area. [whatever we allocate in multipath_run(),
419 * should be freed in multipath_stop()]
420 */
Neil Browne7e72bf2008-05-14 16:05:54 -0700421 mddev->queue->queue_lock = &mddev->queue->__queue_lock;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700422
NeilBrown9ffae0c2006-01-06 00:20:32 -0800423 conf = kzalloc(sizeof(multipath_conf_t), GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700424 mddev->private = conf;
425 if (!conf) {
426 printk(KERN_ERR
427 "multipath: couldn't allocate memory for %s\n",
428 mdname(mddev));
429 goto out;
430 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700431
NeilBrown9ffae0c2006-01-06 00:20:32 -0800432 conf->multipaths = kzalloc(sizeof(struct multipath_info)*mddev->raid_disks,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700433 GFP_KERNEL);
434 if (!conf->multipaths) {
435 printk(KERN_ERR
436 "multipath: couldn't allocate memory for %s\n",
437 mdname(mddev));
438 goto out_free_conf;
439 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700440
Linus Torvalds1da177e2005-04-16 15:20:36 -0700441 conf->working_disks = 0;
NeilBrownd089c6a2008-02-06 01:39:59 -0800442 rdev_for_each(rdev, tmp, mddev) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700443 disk_idx = rdev->raid_disk;
444 if (disk_idx < 0 ||
445 disk_idx >= mddev->raid_disks)
446 continue;
447
448 disk = conf->multipaths + disk_idx;
449 disk->rdev = rdev;
450
451 blk_queue_stack_limits(mddev->queue,
452 rdev->bdev->bd_disk->queue);
453 /* as we don't honour merge_bvec_fn, we must never risk
454 * violating it, not that we ever expect a device with
455 * a merge_bvec_fn to be involved in multipath */
456 if (rdev->bdev->bd_disk->queue->merge_bvec_fn &&
457 mddev->queue->max_sectors > (PAGE_SIZE>>9))
458 blk_queue_max_sectors(mddev->queue, PAGE_SIZE>>9);
459
NeilBrownb2d444d2005-11-08 21:39:31 -0800460 if (!test_bit(Faulty, &rdev->flags))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700461 conf->working_disks++;
462 }
463
464 conf->raid_disks = mddev->raid_disks;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700465 conf->mddev = mddev;
466 spin_lock_init(&conf->device_lock);
467 INIT_LIST_HEAD(&conf->retry_list);
468
469 if (!conf->working_disks) {
470 printk(KERN_ERR "multipath: no operational IO paths for %s\n",
471 mdname(mddev));
472 goto out_free_conf;
473 }
NeilBrown2e333e82006-10-21 10:24:07 -0700474 mddev->degraded = conf->raid_disks - conf->working_disks;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700475
Matthew Dobson26b6e052006-03-26 01:37:48 -0800476 conf->pool = mempool_create_kzalloc_pool(NR_RESERVED_BUFS,
477 sizeof(struct multipath_bh));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700478 if (conf->pool == NULL) {
479 printk(KERN_ERR
480 "multipath: couldn't allocate memory for %s\n",
481 mdname(mddev));
482 goto out_free_conf;
483 }
484
485 {
486 mddev->thread = md_register_thread(multipathd, mddev, "%s_multipath");
487 if (!mddev->thread) {
488 printk(KERN_ERR "multipath: couldn't allocate thread"
489 " for %s\n", mdname(mddev));
490 goto out_free_conf;
491 }
492 }
493
494 printk(KERN_INFO
495 "multipath: array %s active with %d out of %d IO paths\n",
496 mdname(mddev), conf->working_disks, mddev->raid_disks);
497 /*
498 * Ok, everything is just fine now
499 */
500 mddev->array_size = mddev->size;
NeilBrown7a5febe2005-05-16 21:53:16 -0700501
502 mddev->queue->unplug_fn = multipath_unplug;
NeilBrown0d129222006-10-03 01:15:54 -0700503 mddev->queue->backing_dev_info.congested_fn = multipath_congested;
504 mddev->queue->backing_dev_info.congested_data = mddev;
NeilBrown7a5febe2005-05-16 21:53:16 -0700505
Linus Torvalds1da177e2005-04-16 15:20:36 -0700506 return 0;
507
508out_free_conf:
509 if (conf->pool)
510 mempool_destroy(conf->pool);
Jesper Juhl990a8ba2005-06-21 17:17:30 -0700511 kfree(conf->multipaths);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700512 kfree(conf);
513 mddev->private = NULL;
514out:
515 return -EIO;
516}
517
518
519static int multipath_stop (mddev_t *mddev)
520{
521 multipath_conf_t *conf = mddev_to_conf(mddev);
522
523 md_unregister_thread(mddev->thread);
524 mddev->thread = NULL;
525 blk_sync_queue(mddev->queue); /* the unplug fn references 'conf'*/
526 mempool_destroy(conf->pool);
527 kfree(conf->multipaths);
528 kfree(conf);
529 mddev->private = NULL;
530 return 0;
531}
532
NeilBrown2604b702006-01-06 00:20:36 -0800533static struct mdk_personality multipath_personality =
Linus Torvalds1da177e2005-04-16 15:20:36 -0700534{
535 .name = "multipath",
NeilBrown2604b702006-01-06 00:20:36 -0800536 .level = LEVEL_MULTIPATH,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700537 .owner = THIS_MODULE,
538 .make_request = multipath_make_request,
539 .run = multipath_run,
540 .stop = multipath_stop,
541 .status = multipath_status,
542 .error_handler = multipath_error,
543 .hot_add_disk = multipath_add_disk,
544 .hot_remove_disk= multipath_remove_disk,
545};
546
547static int __init multipath_init (void)
548{
NeilBrown2604b702006-01-06 00:20:36 -0800549 return register_md_personality (&multipath_personality);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700550}
551
552static void __exit multipath_exit (void)
553{
NeilBrown2604b702006-01-06 00:20:36 -0800554 unregister_md_personality (&multipath_personality);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700555}
556
557module_init(multipath_init);
558module_exit(multipath_exit);
559MODULE_LICENSE("GPL");
560MODULE_ALIAS("md-personality-7"); /* MULTIPATH */
NeilBrownd9d166c2006-01-06 00:20:51 -0800561MODULE_ALIAS("md-multipath");
NeilBrown2604b702006-01-06 00:20:36 -0800562MODULE_ALIAS("md-level--4");