xref: /linux/drivers/md/raid1.c (revision 6d8854216ebb60959ddb6f4ea4123bd449ba6cf6)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * raid1.c : Multiple Devices driver for Linux
4  *
5  * Copyright (C) 1999, 2000, 2001 Ingo Molnar, Red Hat
6  *
7  * Copyright (C) 1996, 1997, 1998 Ingo Molnar, Miguel de Icaza, Gadi Oxman
8  *
9  * RAID-1 management functions.
10  *
11  * Better read-balancing code written by Mika Kuoppala <miku@iki.fi>, 2000
12  *
13  * Fixes to reconstruction by Jakob Østergaard" <jakob@ostenfeld.dk>
14  * Various fixes by Neil Brown <neilb@cse.unsw.edu.au>
15  *
16  * Changes by Peter T. Breuer <ptb@it.uc3m.es> 31/1/2003 to support
17  * bitmapped intelligence in resync:
18  *
19  *      - bitmap marked during normal i/o
20  *      - bitmap used to skip nondirty blocks during sync
21  *
22  * Additions to bitmap code, (C) 2003-2004 Paul Clements, SteelEye Technology:
23  * - persistent bitmap code
24  */
25 
26 #include <linux/slab.h>
27 #include <linux/delay.h>
28 #include <linux/blkdev.h>
29 #include <linux/module.h>
30 #include <linux/seq_file.h>
31 #include <linux/ratelimit.h>
32 #include <linux/interval_tree_generic.h>
33 
34 #include <trace/events/block.h>
35 
36 #include "md.h"
37 #include "raid1.h"
38 #include "md-bitmap.h"
39 #include "md-cluster.h"
40 
41 #define UNSUPPORTED_MDDEV_FLAGS		\
42 	((1L << MD_HAS_JOURNAL) |	\
43 	 (1L << MD_JOURNAL_CLEAN) |	\
44 	 (1L << MD_HAS_PPL) |		\
45 	 (1L << MD_HAS_MULTIPLE_PPLS))
46 
47 static void allow_barrier(struct r1conf *conf, sector_t sector_nr);
48 static void lower_barrier(struct r1conf *conf, sector_t sector_nr);
49 static void raid1_free(struct mddev *mddev, void *priv);
50 
51 #define RAID_1_10_NAME "raid1"
52 #include "raid1-10.c"
53 
54 #define START(node) ((node)->start)
55 #define LAST(node) ((node)->last)
56 INTERVAL_TREE_DEFINE(struct serial_info, node, sector_t, _subtree_last,
57 		     START, LAST, static inline, raid1_rb);
58 
check_and_add_serial(struct md_rdev * rdev,struct r1bio * r1_bio,struct serial_info * si,int idx)59 static int check_and_add_serial(struct md_rdev *rdev, struct r1bio *r1_bio,
60 				struct serial_info *si, int idx)
61 {
62 	unsigned long flags;
63 	int ret = 0;
64 	sector_t lo = r1_bio->sector;
65 	sector_t hi = lo + r1_bio->sectors;
66 	struct serial_in_rdev *serial = &rdev->serial[idx];
67 
68 	spin_lock_irqsave(&serial->serial_lock, flags);
69 	/* collision happened */
70 	if (raid1_rb_iter_first(&serial->serial_rb, lo, hi))
71 		ret = -EBUSY;
72 	else {
73 		si->start = lo;
74 		si->last = hi;
75 		raid1_rb_insert(si, &serial->serial_rb);
76 	}
77 	spin_unlock_irqrestore(&serial->serial_lock, flags);
78 
79 	return ret;
80 }
81 
wait_for_serialization(struct md_rdev * rdev,struct r1bio * r1_bio)82 static void wait_for_serialization(struct md_rdev *rdev, struct r1bio *r1_bio)
83 {
84 	struct mddev *mddev = rdev->mddev;
85 	struct serial_info *si;
86 	int idx = sector_to_idx(r1_bio->sector);
87 	struct serial_in_rdev *serial = &rdev->serial[idx];
88 
89 	if (WARN_ON(!mddev->serial_info_pool))
90 		return;
91 	si = mempool_alloc(mddev->serial_info_pool, GFP_NOIO);
92 	wait_event(serial->serial_io_wait,
93 		   check_and_add_serial(rdev, r1_bio, si, idx) == 0);
94 }
95 
remove_serial(struct md_rdev * rdev,sector_t lo,sector_t hi)96 static void remove_serial(struct md_rdev *rdev, sector_t lo, sector_t hi)
97 {
98 	struct serial_info *si;
99 	unsigned long flags;
100 	int found = 0;
101 	struct mddev *mddev = rdev->mddev;
102 	int idx = sector_to_idx(lo);
103 	struct serial_in_rdev *serial = &rdev->serial[idx];
104 
105 	spin_lock_irqsave(&serial->serial_lock, flags);
106 	for (si = raid1_rb_iter_first(&serial->serial_rb, lo, hi);
107 	     si; si = raid1_rb_iter_next(si, lo, hi)) {
108 		if (si->start == lo && si->last == hi) {
109 			raid1_rb_remove(si, &serial->serial_rb);
110 			mempool_free(si, mddev->serial_info_pool);
111 			found = 1;
112 			break;
113 		}
114 	}
115 	if (!found)
116 		WARN(1, "The write IO is not recorded for serialization\n");
117 	spin_unlock_irqrestore(&serial->serial_lock, flags);
118 	wake_up(&serial->serial_io_wait);
119 }
120 
121 /*
122  * for resync bio, r1bio pointer can be retrieved from the per-bio
123  * 'struct resync_pages'.
124  */
get_resync_r1bio(struct bio * bio)125 static inline struct r1bio *get_resync_r1bio(struct bio *bio)
126 {
127 	return get_resync_pages(bio)->raid_bio;
128 }
129 
r1bio_pool_alloc(gfp_t gfp_flags,void * data)130 static void * r1bio_pool_alloc(gfp_t gfp_flags, void *data)
131 {
132 	struct pool_info *pi = data;
133 	int size = offsetof(struct r1bio, bios[pi->raid_disks]);
134 
135 	/* allocate a r1bio with room for raid_disks entries in the bios array */
136 	return kzalloc(size, gfp_flags);
137 }
138 
139 #define RESYNC_DEPTH 32
140 #define RESYNC_SECTORS (RESYNC_BLOCK_SIZE >> 9)
141 #define RESYNC_WINDOW (RESYNC_BLOCK_SIZE * RESYNC_DEPTH)
142 #define RESYNC_WINDOW_SECTORS (RESYNC_WINDOW >> 9)
143 #define CLUSTER_RESYNC_WINDOW (16 * RESYNC_WINDOW)
144 #define CLUSTER_RESYNC_WINDOW_SECTORS (CLUSTER_RESYNC_WINDOW >> 9)
145 
r1buf_pool_alloc(gfp_t gfp_flags,void * data)146 static void * r1buf_pool_alloc(gfp_t gfp_flags, void *data)
147 {
148 	struct pool_info *pi = data;
149 	struct r1bio *r1_bio;
150 	struct bio *bio;
151 	int need_pages;
152 	int j;
153 	struct resync_pages *rps;
154 
155 	r1_bio = r1bio_pool_alloc(gfp_flags, pi);
156 	if (!r1_bio)
157 		return NULL;
158 
159 	rps = kmalloc_array(pi->raid_disks, sizeof(struct resync_pages),
160 			    gfp_flags);
161 	if (!rps)
162 		goto out_free_r1bio;
163 
164 	/*
165 	 * Allocate bios : 1 for reading, n-1 for writing
166 	 */
167 	for (j = pi->raid_disks ; j-- ; ) {
168 		bio = bio_kmalloc(RESYNC_PAGES, gfp_flags);
169 		if (!bio)
170 			goto out_free_bio;
171 		bio_init(bio, NULL, bio->bi_inline_vecs, RESYNC_PAGES, 0);
172 		r1_bio->bios[j] = bio;
173 	}
174 	/*
175 	 * Allocate RESYNC_PAGES data pages and attach them to
176 	 * the first bio.
177 	 * If this is a user-requested check/repair, allocate
178 	 * RESYNC_PAGES for each bio.
179 	 */
180 	if (test_bit(MD_RECOVERY_REQUESTED, &pi->mddev->recovery))
181 		need_pages = pi->raid_disks;
182 	else
183 		need_pages = 1;
184 	for (j = 0; j < pi->raid_disks; j++) {
185 		struct resync_pages *rp = &rps[j];
186 
187 		bio = r1_bio->bios[j];
188 
189 		if (j < need_pages) {
190 			if (resync_alloc_pages(rp, gfp_flags))
191 				goto out_free_pages;
192 		} else {
193 			memcpy(rp, &rps[0], sizeof(*rp));
194 			resync_get_all_pages(rp);
195 		}
196 
197 		rp->raid_bio = r1_bio;
198 		bio->bi_private = rp;
199 	}
200 
201 	r1_bio->master_bio = NULL;
202 
203 	return r1_bio;
204 
205 out_free_pages:
206 	while (--j >= 0)
207 		resync_free_pages(&rps[j]);
208 
209 out_free_bio:
210 	while (++j < pi->raid_disks) {
211 		bio_uninit(r1_bio->bios[j]);
212 		kfree(r1_bio->bios[j]);
213 	}
214 	kfree(rps);
215 
216 out_free_r1bio:
217 	rbio_pool_free(r1_bio, data);
218 	return NULL;
219 }
220 
r1buf_pool_free(void * __r1_bio,void * data)221 static void r1buf_pool_free(void *__r1_bio, void *data)
222 {
223 	struct pool_info *pi = data;
224 	int i;
225 	struct r1bio *r1bio = __r1_bio;
226 	struct resync_pages *rp = NULL;
227 
228 	for (i = pi->raid_disks; i--; ) {
229 		rp = get_resync_pages(r1bio->bios[i]);
230 		resync_free_pages(rp);
231 		bio_uninit(r1bio->bios[i]);
232 		kfree(r1bio->bios[i]);
233 	}
234 
235 	/* resync pages array stored in the 1st bio's .bi_private */
236 	kfree(rp);
237 
238 	rbio_pool_free(r1bio, data);
239 }
240 
put_all_bios(struct r1conf * conf,struct r1bio * r1_bio)241 static void put_all_bios(struct r1conf *conf, struct r1bio *r1_bio)
242 {
243 	int i;
244 
245 	for (i = 0; i < conf->raid_disks * 2; i++) {
246 		struct bio **bio = r1_bio->bios + i;
247 		if (!BIO_SPECIAL(*bio))
248 			bio_put(*bio);
249 		*bio = NULL;
250 	}
251 }
252 
free_r1bio(struct r1bio * r1_bio)253 static void free_r1bio(struct r1bio *r1_bio)
254 {
255 	struct r1conf *conf = r1_bio->mddev->private;
256 
257 	put_all_bios(conf, r1_bio);
258 	mempool_free(r1_bio, &conf->r1bio_pool);
259 }
260 
put_buf(struct r1bio * r1_bio)261 static void put_buf(struct r1bio *r1_bio)
262 {
263 	struct r1conf *conf = r1_bio->mddev->private;
264 	sector_t sect = r1_bio->sector;
265 	int i;
266 
267 	for (i = 0; i < conf->raid_disks * 2; i++) {
268 		struct bio *bio = r1_bio->bios[i];
269 		if (bio->bi_end_io)
270 			rdev_dec_pending(conf->mirrors[i].rdev, r1_bio->mddev);
271 	}
272 
273 	mempool_free(r1_bio, &conf->r1buf_pool);
274 
275 	lower_barrier(conf, sect);
276 }
277 
reschedule_retry(struct r1bio * r1_bio)278 static void reschedule_retry(struct r1bio *r1_bio)
279 {
280 	unsigned long flags;
281 	struct mddev *mddev = r1_bio->mddev;
282 	struct r1conf *conf = mddev->private;
283 	int idx;
284 
285 	idx = sector_to_idx(r1_bio->sector);
286 	spin_lock_irqsave(&conf->device_lock, flags);
287 	list_add(&r1_bio->retry_list, &conf->retry_list);
288 	atomic_inc(&conf->nr_queued[idx]);
289 	spin_unlock_irqrestore(&conf->device_lock, flags);
290 
291 	wake_up(&conf->wait_barrier);
292 	md_wakeup_thread(mddev->thread);
293 }
294 
295 /*
296  * raid_end_bio_io() is called when we have finished servicing a mirrored
297  * operation and are ready to return a success/failure code to the buffer
298  * cache layer.
299  */
call_bio_endio(struct r1bio * r1_bio)300 static void call_bio_endio(struct r1bio *r1_bio)
301 {
302 	struct bio *bio = r1_bio->master_bio;
303 
304 	if (!test_bit(R1BIO_Uptodate, &r1_bio->state))
305 		bio->bi_status = BLK_STS_IOERR;
306 
307 	bio_endio(bio);
308 }
309 
raid_end_bio_io(struct r1bio * r1_bio)310 static void raid_end_bio_io(struct r1bio *r1_bio)
311 {
312 	struct bio *bio = r1_bio->master_bio;
313 	struct r1conf *conf = r1_bio->mddev->private;
314 	sector_t sector = r1_bio->sector;
315 
316 	/* if nobody has done the final endio yet, do it now */
317 	if (!test_and_set_bit(R1BIO_Returned, &r1_bio->state)) {
318 		pr_debug("raid1: sync end %s on sectors %llu-%llu\n",
319 			 (bio_data_dir(bio) == WRITE) ? "write" : "read",
320 			 (unsigned long long) bio->bi_iter.bi_sector,
321 			 (unsigned long long) bio_end_sector(bio) - 1);
322 
323 		call_bio_endio(r1_bio);
324 	}
325 
326 	free_r1bio(r1_bio);
327 	/*
328 	 * Wake up any possible resync thread that waits for the device
329 	 * to go idle.  All I/Os, even write-behind writes, are done.
330 	 */
331 	allow_barrier(conf, sector);
332 }
333 
334 /*
335  * Update disk head position estimator based on IRQ completion info.
336  */
update_head_pos(int disk,struct r1bio * r1_bio)337 static inline void update_head_pos(int disk, struct r1bio *r1_bio)
338 {
339 	struct r1conf *conf = r1_bio->mddev->private;
340 
341 	conf->mirrors[disk].head_position =
342 		r1_bio->sector + (r1_bio->sectors);
343 }
344 
345 /*
346  * Find the disk number which triggered given bio
347  */
find_bio_disk(struct r1bio * r1_bio,struct bio * bio)348 static int find_bio_disk(struct r1bio *r1_bio, struct bio *bio)
349 {
350 	int mirror;
351 	struct r1conf *conf = r1_bio->mddev->private;
352 	int raid_disks = conf->raid_disks;
353 
354 	for (mirror = 0; mirror < raid_disks * 2; mirror++)
355 		if (r1_bio->bios[mirror] == bio)
356 			break;
357 
358 	BUG_ON(mirror == raid_disks * 2);
359 	update_head_pos(mirror, r1_bio);
360 
361 	return mirror;
362 }
363 
raid1_end_read_request(struct bio * bio)364 static void raid1_end_read_request(struct bio *bio)
365 {
366 	int uptodate = !bio->bi_status;
367 	struct r1bio *r1_bio = bio->bi_private;
368 	struct r1conf *conf = r1_bio->mddev->private;
369 	struct md_rdev *rdev = conf->mirrors[r1_bio->read_disk].rdev;
370 
371 	/*
372 	 * this branch is our 'one mirror IO has finished' event handler:
373 	 */
374 	update_head_pos(r1_bio->read_disk, r1_bio);
375 
376 	if (uptodate) {
377 		set_bit(R1BIO_Uptodate, &r1_bio->state);
378 	} else if (test_bit(FailFast, &rdev->flags) &&
379 		 test_bit(R1BIO_FailFast, &r1_bio->state)) {
380 		/* This was a fail-fast read so we definitely
381 		 * want to retry */
382 		;
383 	} else if (!raid1_should_handle_error(bio)) {
384 		uptodate = 1;
385 	} else {
386 		/* If all other devices have failed, we want to return
387 		 * the error upwards rather than fail the last device.
388 		 * Here we redefine "uptodate" to mean "Don't want to retry"
389 		 */
390 		unsigned long flags;
391 		spin_lock_irqsave(&conf->device_lock, flags);
392 		if (r1_bio->mddev->degraded == conf->raid_disks ||
393 		    (r1_bio->mddev->degraded == conf->raid_disks-1 &&
394 		     test_bit(In_sync, &rdev->flags)))
395 			uptodate = 1;
396 		spin_unlock_irqrestore(&conf->device_lock, flags);
397 	}
398 
399 	if (uptodate) {
400 		raid_end_bio_io(r1_bio);
401 		rdev_dec_pending(rdev, conf->mddev);
402 	} else {
403 		/*
404 		 * oops, read error:
405 		 */
406 		pr_err_ratelimited("md/raid1:%s: %pg: rescheduling sector %llu\n",
407 				   mdname(conf->mddev),
408 				   rdev->bdev,
409 				   (unsigned long long)r1_bio->sector);
410 		set_bit(R1BIO_ReadError, &r1_bio->state);
411 		reschedule_retry(r1_bio);
412 		/* don't drop the reference on read_disk yet */
413 	}
414 }
415 
close_write(struct r1bio * r1_bio)416 static void close_write(struct r1bio *r1_bio)
417 {
418 	struct mddev *mddev = r1_bio->mddev;
419 
420 	/* it really is the end of this request */
421 	if (test_bit(R1BIO_BehindIO, &r1_bio->state)) {
422 		bio_free_pages(r1_bio->behind_master_bio);
423 		bio_put(r1_bio->behind_master_bio);
424 		r1_bio->behind_master_bio = NULL;
425 	}
426 
427 	if (test_bit(R1BIO_BehindIO, &r1_bio->state))
428 		mddev->bitmap_ops->end_behind_write(mddev);
429 	md_write_end(mddev);
430 }
431 
r1_bio_write_done(struct r1bio * r1_bio)432 static void r1_bio_write_done(struct r1bio *r1_bio)
433 {
434 	if (!atomic_dec_and_test(&r1_bio->remaining))
435 		return;
436 
437 	if (test_bit(R1BIO_WriteError, &r1_bio->state))
438 		reschedule_retry(r1_bio);
439 	else {
440 		close_write(r1_bio);
441 		if (test_bit(R1BIO_MadeGood, &r1_bio->state))
442 			reschedule_retry(r1_bio);
443 		else
444 			raid_end_bio_io(r1_bio);
445 	}
446 }
447 
raid1_end_write_request(struct bio * bio)448 static void raid1_end_write_request(struct bio *bio)
449 {
450 	struct r1bio *r1_bio = bio->bi_private;
451 	int behind = test_bit(R1BIO_BehindIO, &r1_bio->state);
452 	struct r1conf *conf = r1_bio->mddev->private;
453 	struct bio *to_put = NULL;
454 	int mirror = find_bio_disk(r1_bio, bio);
455 	struct md_rdev *rdev = conf->mirrors[mirror].rdev;
456 	sector_t lo = r1_bio->sector;
457 	sector_t hi = r1_bio->sector + r1_bio->sectors;
458 	bool ignore_error = !raid1_should_handle_error(bio) ||
459 		(bio->bi_status && bio_op(bio) == REQ_OP_DISCARD);
460 
461 	/*
462 	 * 'one mirror IO has finished' event handler:
463 	 */
464 	if (bio->bi_status && !ignore_error) {
465 		set_bit(WriteErrorSeen,	&rdev->flags);
466 		if (!test_and_set_bit(WantReplacement, &rdev->flags))
467 			set_bit(MD_RECOVERY_NEEDED, &
468 				conf->mddev->recovery);
469 
470 		if (test_bit(FailFast, &rdev->flags) &&
471 		    (bio->bi_opf & MD_FAILFAST) &&
472 		    /* We never try FailFast to WriteMostly devices */
473 		    !test_bit(WriteMostly, &rdev->flags)) {
474 			md_error(r1_bio->mddev, rdev);
475 		}
476 
477 		/*
478 		 * When the device is faulty, it is not necessary to
479 		 * handle write error.
480 		 */
481 		if (!test_bit(Faulty, &rdev->flags))
482 			set_bit(R1BIO_WriteError, &r1_bio->state);
483 		else {
484 			/* Finished with this branch */
485 			r1_bio->bios[mirror] = NULL;
486 			to_put = bio;
487 		}
488 	} else {
489 		/*
490 		 * Set R1BIO_Uptodate in our master bio, so that we
491 		 * will return a good error code for to the higher
492 		 * levels even if IO on some other mirrored buffer
493 		 * fails.
494 		 *
495 		 * The 'master' represents the composite IO operation
496 		 * to user-side. So if something waits for IO, then it
497 		 * will wait for the 'master' bio.
498 		 */
499 		r1_bio->bios[mirror] = NULL;
500 		to_put = bio;
501 		/*
502 		 * Do not set R1BIO_Uptodate if the current device is
503 		 * rebuilding or Faulty. This is because we cannot use
504 		 * such device for properly reading the data back (we could
505 		 * potentially use it, if the current write would have felt
506 		 * before rdev->recovery_offset, but for simplicity we don't
507 		 * check this here.
508 		 */
509 		if (test_bit(In_sync, &rdev->flags) &&
510 		    !test_bit(Faulty, &rdev->flags))
511 			set_bit(R1BIO_Uptodate, &r1_bio->state);
512 
513 		/* Maybe we can clear some bad blocks. */
514 		if (rdev_has_badblock(rdev, r1_bio->sector, r1_bio->sectors) &&
515 		    !ignore_error) {
516 			r1_bio->bios[mirror] = IO_MADE_GOOD;
517 			set_bit(R1BIO_MadeGood, &r1_bio->state);
518 		}
519 	}
520 
521 	if (behind) {
522 		if (test_bit(CollisionCheck, &rdev->flags))
523 			remove_serial(rdev, lo, hi);
524 		if (test_bit(WriteMostly, &rdev->flags))
525 			atomic_dec(&r1_bio->behind_remaining);
526 
527 		/*
528 		 * In behind mode, we ACK the master bio once the I/O
529 		 * has safely reached all non-writemostly
530 		 * disks. Setting the Returned bit ensures that this
531 		 * gets done only once -- we don't ever want to return
532 		 * -EIO here, instead we'll wait
533 		 */
534 		if (atomic_read(&r1_bio->behind_remaining) >= (atomic_read(&r1_bio->remaining)-1) &&
535 		    test_bit(R1BIO_Uptodate, &r1_bio->state)) {
536 			/* Maybe we can return now */
537 			if (!test_and_set_bit(R1BIO_Returned, &r1_bio->state)) {
538 				struct bio *mbio = r1_bio->master_bio;
539 				pr_debug("raid1: behind end write sectors"
540 					 " %llu-%llu\n",
541 					 (unsigned long long) mbio->bi_iter.bi_sector,
542 					 (unsigned long long) bio_end_sector(mbio) - 1);
543 				call_bio_endio(r1_bio);
544 			}
545 		}
546 	} else if (rdev->mddev->serialize_policy)
547 		remove_serial(rdev, lo, hi);
548 	if (r1_bio->bios[mirror] == NULL)
549 		rdev_dec_pending(rdev, conf->mddev);
550 
551 	/*
552 	 * Let's see if all mirrored write operations have finished
553 	 * already.
554 	 */
555 	r1_bio_write_done(r1_bio);
556 
557 	if (to_put)
558 		bio_put(to_put);
559 }
560 
align_to_barrier_unit_end(sector_t start_sector,sector_t sectors)561 static sector_t align_to_barrier_unit_end(sector_t start_sector,
562 					  sector_t sectors)
563 {
564 	sector_t len;
565 
566 	WARN_ON(sectors == 0);
567 	/*
568 	 * len is the number of sectors from start_sector to end of the
569 	 * barrier unit which start_sector belongs to.
570 	 */
571 	len = round_up(start_sector + 1, BARRIER_UNIT_SECTOR_SIZE) -
572 	      start_sector;
573 
574 	if (len > sectors)
575 		len = sectors;
576 
577 	return len;
578 }
579 
update_read_sectors(struct r1conf * conf,int disk,sector_t this_sector,int len)580 static void update_read_sectors(struct r1conf *conf, int disk,
581 				sector_t this_sector, int len)
582 {
583 	struct raid1_info *info = &conf->mirrors[disk];
584 
585 	atomic_inc(&info->rdev->nr_pending);
586 	if (info->next_seq_sect != this_sector)
587 		info->seq_start = this_sector;
588 	info->next_seq_sect = this_sector + len;
589 }
590 
choose_first_rdev(struct r1conf * conf,struct r1bio * r1_bio,int * max_sectors)591 static int choose_first_rdev(struct r1conf *conf, struct r1bio *r1_bio,
592 			     int *max_sectors)
593 {
594 	sector_t this_sector = r1_bio->sector;
595 	int len = r1_bio->sectors;
596 	int disk;
597 
598 	for (disk = 0 ; disk < conf->raid_disks * 2 ; disk++) {
599 		struct md_rdev *rdev;
600 		int read_len;
601 
602 		if (r1_bio->bios[disk] == IO_BLOCKED)
603 			continue;
604 
605 		rdev = conf->mirrors[disk].rdev;
606 		if (!rdev || test_bit(Faulty, &rdev->flags))
607 			continue;
608 
609 		/* choose the first disk even if it has some bad blocks. */
610 		read_len = raid1_check_read_range(rdev, this_sector, &len);
611 		if (read_len > 0) {
612 			update_read_sectors(conf, disk, this_sector, read_len);
613 			*max_sectors = read_len;
614 			return disk;
615 		}
616 	}
617 
618 	return -1;
619 }
620 
rdev_in_recovery(struct md_rdev * rdev,struct r1bio * r1_bio)621 static bool rdev_in_recovery(struct md_rdev *rdev, struct r1bio *r1_bio)
622 {
623 	return !test_bit(In_sync, &rdev->flags) &&
624 	       rdev->recovery_offset < r1_bio->sector + r1_bio->sectors;
625 }
626 
choose_bb_rdev(struct r1conf * conf,struct r1bio * r1_bio,int * max_sectors)627 static int choose_bb_rdev(struct r1conf *conf, struct r1bio *r1_bio,
628 			  int *max_sectors)
629 {
630 	sector_t this_sector = r1_bio->sector;
631 	int best_disk = -1;
632 	int best_len = 0;
633 	int disk;
634 
635 	for (disk = 0 ; disk < conf->raid_disks * 2 ; disk++) {
636 		struct md_rdev *rdev;
637 		int len;
638 		int read_len;
639 
640 		if (r1_bio->bios[disk] == IO_BLOCKED)
641 			continue;
642 
643 		rdev = conf->mirrors[disk].rdev;
644 		if (!rdev || test_bit(Faulty, &rdev->flags) ||
645 		    rdev_in_recovery(rdev, r1_bio) ||
646 		    test_bit(WriteMostly, &rdev->flags))
647 			continue;
648 
649 		/* keep track of the disk with the most readable sectors. */
650 		len = r1_bio->sectors;
651 		read_len = raid1_check_read_range(rdev, this_sector, &len);
652 		if (read_len > best_len) {
653 			best_disk = disk;
654 			best_len = read_len;
655 		}
656 	}
657 
658 	if (best_disk != -1) {
659 		*max_sectors = best_len;
660 		update_read_sectors(conf, best_disk, this_sector, best_len);
661 	}
662 
663 	return best_disk;
664 }
665 
choose_slow_rdev(struct r1conf * conf,struct r1bio * r1_bio,int * max_sectors)666 static int choose_slow_rdev(struct r1conf *conf, struct r1bio *r1_bio,
667 			    int *max_sectors)
668 {
669 	sector_t this_sector = r1_bio->sector;
670 	int bb_disk = -1;
671 	int bb_read_len = 0;
672 	int disk;
673 
674 	for (disk = 0 ; disk < conf->raid_disks * 2 ; disk++) {
675 		struct md_rdev *rdev;
676 		int len;
677 		int read_len;
678 
679 		if (r1_bio->bios[disk] == IO_BLOCKED)
680 			continue;
681 
682 		rdev = conf->mirrors[disk].rdev;
683 		if (!rdev || test_bit(Faulty, &rdev->flags) ||
684 		    !test_bit(WriteMostly, &rdev->flags) ||
685 		    rdev_in_recovery(rdev, r1_bio))
686 			continue;
687 
688 		/* there are no bad blocks, we can use this disk */
689 		len = r1_bio->sectors;
690 		read_len = raid1_check_read_range(rdev, this_sector, &len);
691 		if (read_len == r1_bio->sectors) {
692 			*max_sectors = read_len;
693 			update_read_sectors(conf, disk, this_sector, read_len);
694 			return disk;
695 		}
696 
697 		/*
698 		 * there are partial bad blocks, choose the rdev with largest
699 		 * read length.
700 		 */
701 		if (read_len > bb_read_len) {
702 			bb_disk = disk;
703 			bb_read_len = read_len;
704 		}
705 	}
706 
707 	if (bb_disk != -1) {
708 		*max_sectors = bb_read_len;
709 		update_read_sectors(conf, bb_disk, this_sector, bb_read_len);
710 	}
711 
712 	return bb_disk;
713 }
714 
is_sequential(struct r1conf * conf,int disk,struct r1bio * r1_bio)715 static bool is_sequential(struct r1conf *conf, int disk, struct r1bio *r1_bio)
716 {
717 	/* TODO: address issues with this check and concurrency. */
718 	return conf->mirrors[disk].next_seq_sect == r1_bio->sector ||
719 	       conf->mirrors[disk].head_position == r1_bio->sector;
720 }
721 
722 /*
723  * If buffered sequential IO size exceeds optimal iosize, check if there is idle
724  * disk. If yes, choose the idle disk.
725  */
should_choose_next(struct r1conf * conf,int disk)726 static bool should_choose_next(struct r1conf *conf, int disk)
727 {
728 	struct raid1_info *mirror = &conf->mirrors[disk];
729 	int opt_iosize;
730 
731 	if (!test_bit(Nonrot, &mirror->rdev->flags))
732 		return false;
733 
734 	opt_iosize = bdev_io_opt(mirror->rdev->bdev) >> 9;
735 	return opt_iosize > 0 && mirror->seq_start != MaxSector &&
736 	       mirror->next_seq_sect > opt_iosize &&
737 	       mirror->next_seq_sect - opt_iosize >= mirror->seq_start;
738 }
739 
rdev_readable(struct md_rdev * rdev,struct r1bio * r1_bio)740 static bool rdev_readable(struct md_rdev *rdev, struct r1bio *r1_bio)
741 {
742 	if (!rdev || test_bit(Faulty, &rdev->flags))
743 		return false;
744 
745 	if (rdev_in_recovery(rdev, r1_bio))
746 		return false;
747 
748 	/* don't read from slow disk unless have to */
749 	if (test_bit(WriteMostly, &rdev->flags))
750 		return false;
751 
752 	/* don't split IO for bad blocks unless have to */
753 	if (rdev_has_badblock(rdev, r1_bio->sector, r1_bio->sectors))
754 		return false;
755 
756 	return true;
757 }
758 
759 struct read_balance_ctl {
760 	sector_t closest_dist;
761 	int closest_dist_disk;
762 	int min_pending;
763 	int min_pending_disk;
764 	int sequential_disk;
765 	int readable_disks;
766 };
767 
choose_best_rdev(struct r1conf * conf,struct r1bio * r1_bio)768 static int choose_best_rdev(struct r1conf *conf, struct r1bio *r1_bio)
769 {
770 	int disk;
771 	struct read_balance_ctl ctl = {
772 		.closest_dist_disk      = -1,
773 		.closest_dist           = MaxSector,
774 		.min_pending_disk       = -1,
775 		.min_pending            = UINT_MAX,
776 		.sequential_disk	= -1,
777 	};
778 
779 	for (disk = 0 ; disk < conf->raid_disks * 2 ; disk++) {
780 		struct md_rdev *rdev;
781 		sector_t dist;
782 		unsigned int pending;
783 
784 		if (r1_bio->bios[disk] == IO_BLOCKED)
785 			continue;
786 
787 		rdev = conf->mirrors[disk].rdev;
788 		if (!rdev_readable(rdev, r1_bio))
789 			continue;
790 
791 		/* At least two disks to choose from so failfast is OK */
792 		if (ctl.readable_disks++ == 1)
793 			set_bit(R1BIO_FailFast, &r1_bio->state);
794 
795 		pending = atomic_read(&rdev->nr_pending);
796 		dist = abs(r1_bio->sector - conf->mirrors[disk].head_position);
797 
798 		/* Don't change to another disk for sequential reads */
799 		if (is_sequential(conf, disk, r1_bio)) {
800 			if (!should_choose_next(conf, disk))
801 				return disk;
802 
803 			/*
804 			 * Add 'pending' to avoid choosing this disk if
805 			 * there is other idle disk.
806 			 */
807 			pending++;
808 			/*
809 			 * If there is no other idle disk, this disk
810 			 * will be chosen.
811 			 */
812 			ctl.sequential_disk = disk;
813 		}
814 
815 		if (ctl.min_pending > pending) {
816 			ctl.min_pending = pending;
817 			ctl.min_pending_disk = disk;
818 		}
819 
820 		if (ctl.closest_dist > dist) {
821 			ctl.closest_dist = dist;
822 			ctl.closest_dist_disk = disk;
823 		}
824 	}
825 
826 	/*
827 	 * sequential IO size exceeds optimal iosize, however, there is no other
828 	 * idle disk, so choose the sequential disk.
829 	 */
830 	if (ctl.sequential_disk != -1 && ctl.min_pending != 0)
831 		return ctl.sequential_disk;
832 
833 	/*
834 	 * If all disks are rotational, choose the closest disk. If any disk is
835 	 * non-rotational, choose the disk with less pending request even the
836 	 * disk is rotational, which might/might not be optimal for raids with
837 	 * mixed ratation/non-rotational disks depending on workload.
838 	 */
839 	if (ctl.min_pending_disk != -1 &&
840 	    (READ_ONCE(conf->nonrot_disks) || ctl.min_pending == 0))
841 		return ctl.min_pending_disk;
842 	else
843 		return ctl.closest_dist_disk;
844 }
845 
846 /*
847  * This routine returns the disk from which the requested read should be done.
848  *
849  * 1) If resync is in progress, find the first usable disk and use it even if it
850  * has some bad blocks.
851  *
852  * 2) Now that there is no resync, loop through all disks and skipping slow
853  * disks and disks with bad blocks for now. Only pay attention to key disk
854  * choice.
855  *
856  * 3) If we've made it this far, now look for disks with bad blocks and choose
857  * the one with most number of sectors.
858  *
859  * 4) If we are all the way at the end, we have no choice but to use a disk even
860  * if it is write mostly.
861  *
862  * The rdev for the device selected will have nr_pending incremented.
863  */
read_balance(struct r1conf * conf,struct r1bio * r1_bio,int * max_sectors)864 static int read_balance(struct r1conf *conf, struct r1bio *r1_bio,
865 			int *max_sectors)
866 {
867 	int disk;
868 
869 	clear_bit(R1BIO_FailFast, &r1_bio->state);
870 
871 	if (raid1_should_read_first(conf->mddev, r1_bio->sector,
872 				    r1_bio->sectors))
873 		return choose_first_rdev(conf, r1_bio, max_sectors);
874 
875 	disk = choose_best_rdev(conf, r1_bio);
876 	if (disk >= 0) {
877 		*max_sectors = r1_bio->sectors;
878 		update_read_sectors(conf, disk, r1_bio->sector,
879 				    r1_bio->sectors);
880 		return disk;
881 	}
882 
883 	/*
884 	 * If we are here it means we didn't find a perfectly good disk so
885 	 * now spend a bit more time trying to find one with the most good
886 	 * sectors.
887 	 */
888 	disk = choose_bb_rdev(conf, r1_bio, max_sectors);
889 	if (disk >= 0)
890 		return disk;
891 
892 	return choose_slow_rdev(conf, r1_bio, max_sectors);
893 }
894 
wake_up_barrier(struct r1conf * conf)895 static void wake_up_barrier(struct r1conf *conf)
896 {
897 	if (wq_has_sleeper(&conf->wait_barrier))
898 		wake_up(&conf->wait_barrier);
899 }
900 
flush_bio_list(struct r1conf * conf,struct bio * bio)901 static void flush_bio_list(struct r1conf *conf, struct bio *bio)
902 {
903 	/* flush any pending bitmap writes to disk before proceeding w/ I/O */
904 	raid1_prepare_flush_writes(conf->mddev);
905 	wake_up_barrier(conf);
906 
907 	while (bio) { /* submit pending writes */
908 		struct bio *next = bio->bi_next;
909 
910 		raid1_submit_write(bio);
911 		bio = next;
912 		cond_resched();
913 	}
914 }
915 
flush_pending_writes(struct r1conf * conf)916 static void flush_pending_writes(struct r1conf *conf)
917 {
918 	/* Any writes that have been queued but are awaiting
919 	 * bitmap updates get flushed here.
920 	 */
921 	spin_lock_irq(&conf->device_lock);
922 
923 	if (conf->pending_bio_list.head) {
924 		struct blk_plug plug;
925 		struct bio *bio;
926 
927 		bio = bio_list_get(&conf->pending_bio_list);
928 		spin_unlock_irq(&conf->device_lock);
929 
930 		/*
931 		 * As this is called in a wait_event() loop (see freeze_array),
932 		 * current->state might be TASK_UNINTERRUPTIBLE which will
933 		 * cause a warning when we prepare to wait again.  As it is
934 		 * rare that this path is taken, it is perfectly safe to force
935 		 * us to go around the wait_event() loop again, so the warning
936 		 * is a false-positive.  Silence the warning by resetting
937 		 * thread state
938 		 */
939 		__set_current_state(TASK_RUNNING);
940 		blk_start_plug(&plug);
941 		flush_bio_list(conf, bio);
942 		blk_finish_plug(&plug);
943 	} else
944 		spin_unlock_irq(&conf->device_lock);
945 }
946 
947 /* Barriers....
948  * Sometimes we need to suspend IO while we do something else,
949  * either some resync/recovery, or reconfigure the array.
950  * To do this we raise a 'barrier'.
951  * The 'barrier' is a counter that can be raised multiple times
952  * to count how many activities are happening which preclude
953  * normal IO.
954  * We can only raise the barrier if there is no pending IO.
955  * i.e. if nr_pending == 0.
956  * We choose only to raise the barrier if no-one is waiting for the
957  * barrier to go down.  This means that as soon as an IO request
958  * is ready, no other operations which require a barrier will start
959  * until the IO request has had a chance.
960  *
961  * So: regular IO calls 'wait_barrier'.  When that returns there
962  *    is no backgroup IO happening,  It must arrange to call
963  *    allow_barrier when it has finished its IO.
964  * backgroup IO calls must call raise_barrier.  Once that returns
965  *    there is no normal IO happeing.  It must arrange to call
966  *    lower_barrier when the particular background IO completes.
967  *
968  * If resync/recovery is interrupted, returns -EINTR;
969  * Otherwise, returns 0.
970  */
raise_barrier(struct r1conf * conf,sector_t sector_nr)971 static int raise_barrier(struct r1conf *conf, sector_t sector_nr)
972 {
973 	int idx = sector_to_idx(sector_nr);
974 
975 	spin_lock_irq(&conf->resync_lock);
976 
977 	/* Wait until no block IO is waiting */
978 	wait_event_lock_irq(conf->wait_barrier,
979 			    !atomic_read(&conf->nr_waiting[idx]),
980 			    conf->resync_lock);
981 
982 	/* block any new IO from starting */
983 	atomic_inc(&conf->barrier[idx]);
984 	/*
985 	 * In raise_barrier() we firstly increase conf->barrier[idx] then
986 	 * check conf->nr_pending[idx]. In _wait_barrier() we firstly
987 	 * increase conf->nr_pending[idx] then check conf->barrier[idx].
988 	 * A memory barrier here to make sure conf->nr_pending[idx] won't
989 	 * be fetched before conf->barrier[idx] is increased. Otherwise
990 	 * there will be a race between raise_barrier() and _wait_barrier().
991 	 */
992 	smp_mb__after_atomic();
993 
994 	/* For these conditions we must wait:
995 	 * A: while the array is in frozen state
996 	 * B: while conf->nr_pending[idx] is not 0, meaning regular I/O
997 	 *    existing in corresponding I/O barrier bucket.
998 	 * C: while conf->barrier[idx] >= RESYNC_DEPTH, meaning reaches
999 	 *    max resync count which allowed on current I/O barrier bucket.
1000 	 */
1001 	wait_event_lock_irq(conf->wait_barrier,
1002 			    (!conf->array_frozen &&
1003 			     !atomic_read(&conf->nr_pending[idx]) &&
1004 			     atomic_read(&conf->barrier[idx]) < RESYNC_DEPTH) ||
1005 				test_bit(MD_RECOVERY_INTR, &conf->mddev->recovery),
1006 			    conf->resync_lock);
1007 
1008 	if (test_bit(MD_RECOVERY_INTR, &conf->mddev->recovery)) {
1009 		atomic_dec(&conf->barrier[idx]);
1010 		spin_unlock_irq(&conf->resync_lock);
1011 		wake_up(&conf->wait_barrier);
1012 		return -EINTR;
1013 	}
1014 
1015 	atomic_inc(&conf->nr_sync_pending);
1016 	spin_unlock_irq(&conf->resync_lock);
1017 
1018 	return 0;
1019 }
1020 
lower_barrier(struct r1conf * conf,sector_t sector_nr)1021 static void lower_barrier(struct r1conf *conf, sector_t sector_nr)
1022 {
1023 	int idx = sector_to_idx(sector_nr);
1024 
1025 	BUG_ON(atomic_read(&conf->barrier[idx]) <= 0);
1026 
1027 	atomic_dec(&conf->barrier[idx]);
1028 	atomic_dec(&conf->nr_sync_pending);
1029 	wake_up(&conf->wait_barrier);
1030 }
1031 
_wait_barrier(struct r1conf * conf,int idx,bool nowait)1032 static bool _wait_barrier(struct r1conf *conf, int idx, bool nowait)
1033 {
1034 	bool ret = true;
1035 
1036 	/*
1037 	 * We need to increase conf->nr_pending[idx] very early here,
1038 	 * then raise_barrier() can be blocked when it waits for
1039 	 * conf->nr_pending[idx] to be 0. Then we can avoid holding
1040 	 * conf->resync_lock when there is no barrier raised in same
1041 	 * barrier unit bucket. Also if the array is frozen, I/O
1042 	 * should be blocked until array is unfrozen.
1043 	 */
1044 	atomic_inc(&conf->nr_pending[idx]);
1045 	/*
1046 	 * In _wait_barrier() we firstly increase conf->nr_pending[idx], then
1047 	 * check conf->barrier[idx]. In raise_barrier() we firstly increase
1048 	 * conf->barrier[idx], then check conf->nr_pending[idx]. A memory
1049 	 * barrier is necessary here to make sure conf->barrier[idx] won't be
1050 	 * fetched before conf->nr_pending[idx] is increased. Otherwise there
1051 	 * will be a race between _wait_barrier() and raise_barrier().
1052 	 */
1053 	smp_mb__after_atomic();
1054 
1055 	/*
1056 	 * Don't worry about checking two atomic_t variables at same time
1057 	 * here. If during we check conf->barrier[idx], the array is
1058 	 * frozen (conf->array_frozen is 1), and chonf->barrier[idx] is
1059 	 * 0, it is safe to return and make the I/O continue. Because the
1060 	 * array is frozen, all I/O returned here will eventually complete
1061 	 * or be queued, no race will happen. See code comment in
1062 	 * frozen_array().
1063 	 */
1064 	if (!READ_ONCE(conf->array_frozen) &&
1065 	    !atomic_read(&conf->barrier[idx]))
1066 		return ret;
1067 
1068 	/*
1069 	 * After holding conf->resync_lock, conf->nr_pending[idx]
1070 	 * should be decreased before waiting for barrier to drop.
1071 	 * Otherwise, we may encounter a race condition because
1072 	 * raise_barrer() might be waiting for conf->nr_pending[idx]
1073 	 * to be 0 at same time.
1074 	 */
1075 	spin_lock_irq(&conf->resync_lock);
1076 	atomic_inc(&conf->nr_waiting[idx]);
1077 	atomic_dec(&conf->nr_pending[idx]);
1078 	/*
1079 	 * In case freeze_array() is waiting for
1080 	 * get_unqueued_pending() == extra
1081 	 */
1082 	wake_up_barrier(conf);
1083 	/* Wait for the barrier in same barrier unit bucket to drop. */
1084 
1085 	/* Return false when nowait flag is set */
1086 	if (nowait) {
1087 		ret = false;
1088 	} else {
1089 		wait_event_lock_irq(conf->wait_barrier,
1090 				!conf->array_frozen &&
1091 				!atomic_read(&conf->barrier[idx]),
1092 				conf->resync_lock);
1093 		atomic_inc(&conf->nr_pending[idx]);
1094 	}
1095 
1096 	atomic_dec(&conf->nr_waiting[idx]);
1097 	spin_unlock_irq(&conf->resync_lock);
1098 	return ret;
1099 }
1100 
wait_read_barrier(struct r1conf * conf,sector_t sector_nr,bool nowait)1101 static bool wait_read_barrier(struct r1conf *conf, sector_t sector_nr, bool nowait)
1102 {
1103 	int idx = sector_to_idx(sector_nr);
1104 	bool ret = true;
1105 
1106 	/*
1107 	 * Very similar to _wait_barrier(). The difference is, for read
1108 	 * I/O we don't need wait for sync I/O, but if the whole array
1109 	 * is frozen, the read I/O still has to wait until the array is
1110 	 * unfrozen. Since there is no ordering requirement with
1111 	 * conf->barrier[idx] here, memory barrier is unnecessary as well.
1112 	 */
1113 	atomic_inc(&conf->nr_pending[idx]);
1114 
1115 	if (!READ_ONCE(conf->array_frozen))
1116 		return ret;
1117 
1118 	spin_lock_irq(&conf->resync_lock);
1119 	atomic_inc(&conf->nr_waiting[idx]);
1120 	atomic_dec(&conf->nr_pending[idx]);
1121 	/*
1122 	 * In case freeze_array() is waiting for
1123 	 * get_unqueued_pending() == extra
1124 	 */
1125 	wake_up_barrier(conf);
1126 	/* Wait for array to be unfrozen */
1127 
1128 	/* Return false when nowait flag is set */
1129 	if (nowait) {
1130 		/* Return false when nowait flag is set */
1131 		ret = false;
1132 	} else {
1133 		wait_event_lock_irq(conf->wait_barrier,
1134 				!conf->array_frozen,
1135 				conf->resync_lock);
1136 		atomic_inc(&conf->nr_pending[idx]);
1137 	}
1138 
1139 	atomic_dec(&conf->nr_waiting[idx]);
1140 	spin_unlock_irq(&conf->resync_lock);
1141 	return ret;
1142 }
1143 
wait_barrier(struct r1conf * conf,sector_t sector_nr,bool nowait)1144 static bool wait_barrier(struct r1conf *conf, sector_t sector_nr, bool nowait)
1145 {
1146 	int idx = sector_to_idx(sector_nr);
1147 
1148 	return _wait_barrier(conf, idx, nowait);
1149 }
1150 
_allow_barrier(struct r1conf * conf,int idx)1151 static void _allow_barrier(struct r1conf *conf, int idx)
1152 {
1153 	atomic_dec(&conf->nr_pending[idx]);
1154 	wake_up_barrier(conf);
1155 }
1156 
allow_barrier(struct r1conf * conf,sector_t sector_nr)1157 static void allow_barrier(struct r1conf *conf, sector_t sector_nr)
1158 {
1159 	int idx = sector_to_idx(sector_nr);
1160 
1161 	_allow_barrier(conf, idx);
1162 }
1163 
1164 /* conf->resync_lock should be held */
get_unqueued_pending(struct r1conf * conf)1165 static int get_unqueued_pending(struct r1conf *conf)
1166 {
1167 	int idx, ret;
1168 
1169 	ret = atomic_read(&conf->nr_sync_pending);
1170 	for (idx = 0; idx < BARRIER_BUCKETS_NR; idx++)
1171 		ret += atomic_read(&conf->nr_pending[idx]) -
1172 			atomic_read(&conf->nr_queued[idx]);
1173 
1174 	return ret;
1175 }
1176 
freeze_array(struct r1conf * conf,int extra)1177 static void freeze_array(struct r1conf *conf, int extra)
1178 {
1179 	/* Stop sync I/O and normal I/O and wait for everything to
1180 	 * go quiet.
1181 	 * This is called in two situations:
1182 	 * 1) management command handlers (reshape, remove disk, quiesce).
1183 	 * 2) one normal I/O request failed.
1184 
1185 	 * After array_frozen is set to 1, new sync IO will be blocked at
1186 	 * raise_barrier(), and new normal I/O will blocked at _wait_barrier()
1187 	 * or wait_read_barrier(). The flying I/Os will either complete or be
1188 	 * queued. When everything goes quite, there are only queued I/Os left.
1189 
1190 	 * Every flying I/O contributes to a conf->nr_pending[idx], idx is the
1191 	 * barrier bucket index which this I/O request hits. When all sync and
1192 	 * normal I/O are queued, sum of all conf->nr_pending[] will match sum
1193 	 * of all conf->nr_queued[]. But normal I/O failure is an exception,
1194 	 * in handle_read_error(), we may call freeze_array() before trying to
1195 	 * fix the read error. In this case, the error read I/O is not queued,
1196 	 * so get_unqueued_pending() == 1.
1197 	 *
1198 	 * Therefore before this function returns, we need to wait until
1199 	 * get_unqueued_pendings(conf) gets equal to extra. For
1200 	 * normal I/O context, extra is 1, in rested situations extra is 0.
1201 	 */
1202 	spin_lock_irq(&conf->resync_lock);
1203 	conf->array_frozen = 1;
1204 	mddev_add_trace_msg(conf->mddev, "raid1 wait freeze");
1205 	wait_event_lock_irq_cmd(
1206 		conf->wait_barrier,
1207 		get_unqueued_pending(conf) == extra,
1208 		conf->resync_lock,
1209 		flush_pending_writes(conf));
1210 	spin_unlock_irq(&conf->resync_lock);
1211 }
unfreeze_array(struct r1conf * conf)1212 static void unfreeze_array(struct r1conf *conf)
1213 {
1214 	/* reverse the effect of the freeze */
1215 	spin_lock_irq(&conf->resync_lock);
1216 	conf->array_frozen = 0;
1217 	spin_unlock_irq(&conf->resync_lock);
1218 	wake_up(&conf->wait_barrier);
1219 }
1220 
alloc_behind_master_bio(struct r1bio * r1_bio,struct bio * bio)1221 static void alloc_behind_master_bio(struct r1bio *r1_bio,
1222 					   struct bio *bio)
1223 {
1224 	int size = bio->bi_iter.bi_size;
1225 	unsigned vcnt = (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
1226 	int i = 0;
1227 	struct bio *behind_bio = NULL;
1228 
1229 	behind_bio = bio_alloc_bioset(NULL, vcnt, 0, GFP_NOIO,
1230 				      &r1_bio->mddev->bio_set);
1231 
1232 	/* discard op, we don't support writezero/writesame yet */
1233 	if (!bio_has_data(bio)) {
1234 		behind_bio->bi_iter.bi_size = size;
1235 		goto skip_copy;
1236 	}
1237 
1238 	while (i < vcnt && size) {
1239 		struct page *page;
1240 		int len = min_t(int, PAGE_SIZE, size);
1241 
1242 		page = alloc_page(GFP_NOIO);
1243 		if (unlikely(!page))
1244 			goto free_pages;
1245 
1246 		if (!bio_add_page(behind_bio, page, len, 0)) {
1247 			put_page(page);
1248 			goto free_pages;
1249 		}
1250 
1251 		size -= len;
1252 		i++;
1253 	}
1254 
1255 	bio_copy_data(behind_bio, bio);
1256 skip_copy:
1257 	r1_bio->behind_master_bio = behind_bio;
1258 	set_bit(R1BIO_BehindIO, &r1_bio->state);
1259 
1260 	return;
1261 
1262 free_pages:
1263 	pr_debug("%dB behind alloc failed, doing sync I/O\n",
1264 		 bio->bi_iter.bi_size);
1265 	bio_free_pages(behind_bio);
1266 	bio_put(behind_bio);
1267 }
1268 
raid1_unplug(struct blk_plug_cb * cb,bool from_schedule)1269 static void raid1_unplug(struct blk_plug_cb *cb, bool from_schedule)
1270 {
1271 	struct raid1_plug_cb *plug = container_of(cb, struct raid1_plug_cb,
1272 						  cb);
1273 	struct mddev *mddev = plug->cb.data;
1274 	struct r1conf *conf = mddev->private;
1275 	struct bio *bio;
1276 
1277 	if (from_schedule) {
1278 		spin_lock_irq(&conf->device_lock);
1279 		bio_list_merge(&conf->pending_bio_list, &plug->pending);
1280 		spin_unlock_irq(&conf->device_lock);
1281 		wake_up_barrier(conf);
1282 		md_wakeup_thread(mddev->thread);
1283 		kfree(plug);
1284 		return;
1285 	}
1286 
1287 	/* we aren't scheduling, so we can do the write-out directly. */
1288 	bio = bio_list_get(&plug->pending);
1289 	flush_bio_list(conf, bio);
1290 	kfree(plug);
1291 }
1292 
init_r1bio(struct r1bio * r1_bio,struct mddev * mddev,struct bio * bio)1293 static void init_r1bio(struct r1bio *r1_bio, struct mddev *mddev, struct bio *bio)
1294 {
1295 	r1_bio->master_bio = bio;
1296 	r1_bio->sectors = bio_sectors(bio);
1297 	r1_bio->state = 0;
1298 	r1_bio->mddev = mddev;
1299 	r1_bio->sector = bio->bi_iter.bi_sector;
1300 }
1301 
1302 static inline struct r1bio *
alloc_r1bio(struct mddev * mddev,struct bio * bio)1303 alloc_r1bio(struct mddev *mddev, struct bio *bio)
1304 {
1305 	struct r1conf *conf = mddev->private;
1306 	struct r1bio *r1_bio;
1307 
1308 	r1_bio = mempool_alloc(&conf->r1bio_pool, GFP_NOIO);
1309 	/* Ensure no bio records IO_BLOCKED */
1310 	memset(r1_bio->bios, 0, conf->raid_disks * sizeof(r1_bio->bios[0]));
1311 	init_r1bio(r1_bio, mddev, bio);
1312 	return r1_bio;
1313 }
1314 
raid1_read_request(struct mddev * mddev,struct bio * bio,int max_read_sectors,struct r1bio * r1_bio)1315 static void raid1_read_request(struct mddev *mddev, struct bio *bio,
1316 			       int max_read_sectors, struct r1bio *r1_bio)
1317 {
1318 	struct r1conf *conf = mddev->private;
1319 	struct raid1_info *mirror;
1320 	struct bio *read_bio;
1321 	int max_sectors;
1322 	int rdisk, error;
1323 	bool r1bio_existed = !!r1_bio;
1324 
1325 	/*
1326 	 * If r1_bio is set, we are blocking the raid1d thread
1327 	 * so there is a tiny risk of deadlock.  So ask for
1328 	 * emergency memory if needed.
1329 	 */
1330 	gfp_t gfp = r1_bio ? (GFP_NOIO | __GFP_HIGH) : GFP_NOIO;
1331 
1332 	/*
1333 	 * Still need barrier for READ in case that whole
1334 	 * array is frozen.
1335 	 */
1336 	if (!wait_read_barrier(conf, bio->bi_iter.bi_sector,
1337 				bio->bi_opf & REQ_NOWAIT)) {
1338 		bio_wouldblock_error(bio);
1339 		return;
1340 	}
1341 
1342 	if (!r1_bio)
1343 		r1_bio = alloc_r1bio(mddev, bio);
1344 	else
1345 		init_r1bio(r1_bio, mddev, bio);
1346 	r1_bio->sectors = max_read_sectors;
1347 
1348 	/*
1349 	 * make_request() can abort the operation when read-ahead is being
1350 	 * used and no empty request is available.
1351 	 */
1352 	rdisk = read_balance(conf, r1_bio, &max_sectors);
1353 	if (rdisk < 0) {
1354 		/* couldn't find anywhere to read from */
1355 		if (r1bio_existed)
1356 			pr_crit_ratelimited("md/raid1:%s: %pg: unrecoverable I/O read error for block %llu\n",
1357 					    mdname(mddev),
1358 					    conf->mirrors[r1_bio->read_disk].rdev->bdev,
1359 					    r1_bio->sector);
1360 		raid_end_bio_io(r1_bio);
1361 		return;
1362 	}
1363 	mirror = conf->mirrors + rdisk;
1364 
1365 	if (r1bio_existed)
1366 		pr_info_ratelimited("md/raid1:%s: redirecting sector %llu to other mirror: %pg\n",
1367 				    mdname(mddev),
1368 				    (unsigned long long)r1_bio->sector,
1369 				    mirror->rdev->bdev);
1370 
1371 	if (test_bit(WriteMostly, &mirror->rdev->flags)) {
1372 		/*
1373 		 * Reading from a write-mostly device must take care not to
1374 		 * over-take any writes that are 'behind'
1375 		 */
1376 		mddev_add_trace_msg(mddev, "raid1 wait behind writes");
1377 		mddev->bitmap_ops->wait_behind_writes(mddev);
1378 	}
1379 
1380 	if (max_sectors < bio_sectors(bio)) {
1381 		struct bio *split = bio_split(bio, max_sectors,
1382 					      gfp, &conf->bio_split);
1383 
1384 		if (IS_ERR(split)) {
1385 			error = PTR_ERR(split);
1386 			goto err_handle;
1387 		}
1388 		bio_chain(split, bio);
1389 		submit_bio_noacct(bio);
1390 		bio = split;
1391 		r1_bio->master_bio = bio;
1392 		r1_bio->sectors = max_sectors;
1393 	}
1394 
1395 	r1_bio->read_disk = rdisk;
1396 	if (!r1bio_existed) {
1397 		md_account_bio(mddev, &bio);
1398 		r1_bio->master_bio = bio;
1399 	}
1400 	read_bio = bio_alloc_clone(mirror->rdev->bdev, bio, gfp,
1401 				   &mddev->bio_set);
1402 
1403 	r1_bio->bios[rdisk] = read_bio;
1404 
1405 	read_bio->bi_iter.bi_sector = r1_bio->sector +
1406 		mirror->rdev->data_offset;
1407 	read_bio->bi_end_io = raid1_end_read_request;
1408 	if (test_bit(FailFast, &mirror->rdev->flags) &&
1409 	    test_bit(R1BIO_FailFast, &r1_bio->state))
1410 	        read_bio->bi_opf |= MD_FAILFAST;
1411 	read_bio->bi_private = r1_bio;
1412 	mddev_trace_remap(mddev, read_bio, r1_bio->sector);
1413 	submit_bio_noacct(read_bio);
1414 	return;
1415 
1416 err_handle:
1417 	atomic_dec(&mirror->rdev->nr_pending);
1418 	bio->bi_status = errno_to_blk_status(error);
1419 	set_bit(R1BIO_Uptodate, &r1_bio->state);
1420 	raid_end_bio_io(r1_bio);
1421 }
1422 
wait_blocked_rdev(struct mddev * mddev,struct bio * bio)1423 static bool wait_blocked_rdev(struct mddev *mddev, struct bio *bio)
1424 {
1425 	struct r1conf *conf = mddev->private;
1426 	int disks = conf->raid_disks * 2;
1427 	int i;
1428 
1429 retry:
1430 	for (i = 0; i < disks; i++) {
1431 		struct md_rdev *rdev = conf->mirrors[i].rdev;
1432 
1433 		if (!rdev)
1434 			continue;
1435 
1436 		/* don't write here until the bad block is acknowledged */
1437 		if (test_bit(WriteErrorSeen, &rdev->flags) &&
1438 		    rdev_has_badblock(rdev, bio->bi_iter.bi_sector,
1439 				      bio_sectors(bio)) < 0)
1440 			set_bit(BlockedBadBlocks, &rdev->flags);
1441 
1442 		if (rdev_blocked(rdev)) {
1443 			if (bio->bi_opf & REQ_NOWAIT)
1444 				return false;
1445 
1446 			mddev_add_trace_msg(rdev->mddev, "raid1 wait rdev %d blocked",
1447 					    rdev->raid_disk);
1448 			atomic_inc(&rdev->nr_pending);
1449 			md_wait_for_blocked_rdev(rdev, rdev->mddev);
1450 			goto retry;
1451 		}
1452 	}
1453 
1454 	return true;
1455 }
1456 
raid1_write_request(struct mddev * mddev,struct bio * bio,int max_write_sectors)1457 static void raid1_write_request(struct mddev *mddev, struct bio *bio,
1458 				int max_write_sectors)
1459 {
1460 	struct r1conf *conf = mddev->private;
1461 	struct r1bio *r1_bio;
1462 	int i, disks, k, error;
1463 	unsigned long flags;
1464 	int first_clone;
1465 	int max_sectors;
1466 	bool write_behind = false;
1467 	bool is_discard = (bio_op(bio) == REQ_OP_DISCARD);
1468 
1469 	if (mddev_is_clustered(mddev) &&
1470 	    mddev->cluster_ops->area_resyncing(mddev, WRITE,
1471 		     bio->bi_iter.bi_sector, bio_end_sector(bio))) {
1472 
1473 		DEFINE_WAIT(w);
1474 		if (bio->bi_opf & REQ_NOWAIT) {
1475 			bio_wouldblock_error(bio);
1476 			return;
1477 		}
1478 		for (;;) {
1479 			prepare_to_wait(&conf->wait_barrier,
1480 					&w, TASK_IDLE);
1481 			if (!mddev->cluster_ops->area_resyncing(mddev, WRITE,
1482 							bio->bi_iter.bi_sector,
1483 							bio_end_sector(bio)))
1484 				break;
1485 			schedule();
1486 		}
1487 		finish_wait(&conf->wait_barrier, &w);
1488 	}
1489 
1490 	/*
1491 	 * Register the new request and wait if the reconstruction
1492 	 * thread has put up a bar for new requests.
1493 	 * Continue immediately if no resync is active currently.
1494 	 */
1495 	if (!wait_barrier(conf, bio->bi_iter.bi_sector,
1496 				bio->bi_opf & REQ_NOWAIT)) {
1497 		bio_wouldblock_error(bio);
1498 		return;
1499 	}
1500 
1501 	if (!wait_blocked_rdev(mddev, bio)) {
1502 		bio_wouldblock_error(bio);
1503 		return;
1504 	}
1505 
1506 	r1_bio = alloc_r1bio(mddev, bio);
1507 	r1_bio->sectors = max_write_sectors;
1508 
1509 	/* first select target devices under rcu_lock and
1510 	 * inc refcount on their rdev.  Record them by setting
1511 	 * bios[x] to bio
1512 	 * If there are known/acknowledged bad blocks on any device on
1513 	 * which we have seen a write error, we want to avoid writing those
1514 	 * blocks.
1515 	 * This potentially requires several writes to write around
1516 	 * the bad blocks.  Each set of writes gets it's own r1bio
1517 	 * with a set of bios attached.
1518 	 */
1519 
1520 	disks = conf->raid_disks * 2;
1521 	max_sectors = r1_bio->sectors;
1522 	for (i = 0;  i < disks; i++) {
1523 		struct md_rdev *rdev = conf->mirrors[i].rdev;
1524 
1525 		/*
1526 		 * The write-behind io is only attempted on drives marked as
1527 		 * write-mostly, which means we could allocate write behind
1528 		 * bio later.
1529 		 */
1530 		if (!is_discard && rdev && test_bit(WriteMostly, &rdev->flags))
1531 			write_behind = true;
1532 
1533 		r1_bio->bios[i] = NULL;
1534 		if (!rdev || test_bit(Faulty, &rdev->flags))
1535 			continue;
1536 
1537 		atomic_inc(&rdev->nr_pending);
1538 		if (test_bit(WriteErrorSeen, &rdev->flags)) {
1539 			sector_t first_bad;
1540 			sector_t bad_sectors;
1541 			int is_bad;
1542 
1543 			is_bad = is_badblock(rdev, r1_bio->sector, max_sectors,
1544 					     &first_bad, &bad_sectors);
1545 			if (is_bad && first_bad <= r1_bio->sector) {
1546 				/* Cannot write here at all */
1547 				bad_sectors -= (r1_bio->sector - first_bad);
1548 				if (bad_sectors < max_sectors)
1549 					/* mustn't write more than bad_sectors
1550 					 * to other devices yet
1551 					 */
1552 					max_sectors = bad_sectors;
1553 				rdev_dec_pending(rdev, mddev);
1554 				continue;
1555 			}
1556 			if (is_bad) {
1557 				int good_sectors;
1558 
1559 				/*
1560 				 * We cannot atomically write this, so just
1561 				 * error in that case. It could be possible to
1562 				 * atomically write other mirrors, but the
1563 				 * complexity of supporting that is not worth
1564 				 * the benefit.
1565 				 */
1566 				if (bio->bi_opf & REQ_ATOMIC) {
1567 					error = -EIO;
1568 					goto err_handle;
1569 				}
1570 
1571 				good_sectors = first_bad - r1_bio->sector;
1572 				if (good_sectors < max_sectors)
1573 					max_sectors = good_sectors;
1574 			}
1575 		}
1576 		r1_bio->bios[i] = bio;
1577 	}
1578 
1579 	/*
1580 	 * When using a bitmap, we may call alloc_behind_master_bio below.
1581 	 * alloc_behind_master_bio allocates a copy of the data payload a page
1582 	 * at a time and thus needs a new bio that can fit the whole payload
1583 	 * this bio in page sized chunks.
1584 	 */
1585 	if (write_behind && mddev->bitmap)
1586 		max_sectors = min_t(int, max_sectors,
1587 				    BIO_MAX_VECS * (PAGE_SIZE >> 9));
1588 	if (max_sectors < bio_sectors(bio)) {
1589 		struct bio *split = bio_split(bio, max_sectors,
1590 					      GFP_NOIO, &conf->bio_split);
1591 
1592 		if (IS_ERR(split)) {
1593 			error = PTR_ERR(split);
1594 			goto err_handle;
1595 		}
1596 		bio_chain(split, bio);
1597 		submit_bio_noacct(bio);
1598 		bio = split;
1599 		r1_bio->master_bio = bio;
1600 		r1_bio->sectors = max_sectors;
1601 	}
1602 
1603 	md_account_bio(mddev, &bio);
1604 	r1_bio->master_bio = bio;
1605 	atomic_set(&r1_bio->remaining, 1);
1606 	atomic_set(&r1_bio->behind_remaining, 0);
1607 
1608 	first_clone = 1;
1609 
1610 	for (i = 0; i < disks; i++) {
1611 		struct bio *mbio = NULL;
1612 		struct md_rdev *rdev = conf->mirrors[i].rdev;
1613 		if (!r1_bio->bios[i])
1614 			continue;
1615 
1616 		if (first_clone) {
1617 			unsigned long max_write_behind =
1618 				mddev->bitmap_info.max_write_behind;
1619 			struct md_bitmap_stats stats;
1620 			int err;
1621 
1622 			/* do behind I/O ?
1623 			 * Not if there are too many, or cannot
1624 			 * allocate memory, or a reader on WriteMostly
1625 			 * is waiting for behind writes to flush */
1626 			err = mddev->bitmap_ops->get_stats(mddev->bitmap, &stats);
1627 			if (!err && write_behind && !stats.behind_wait &&
1628 			    stats.behind_writes < max_write_behind)
1629 				alloc_behind_master_bio(r1_bio, bio);
1630 
1631 			if (test_bit(R1BIO_BehindIO, &r1_bio->state))
1632 				mddev->bitmap_ops->start_behind_write(mddev);
1633 			first_clone = 0;
1634 		}
1635 
1636 		if (r1_bio->behind_master_bio) {
1637 			mbio = bio_alloc_clone(rdev->bdev,
1638 					       r1_bio->behind_master_bio,
1639 					       GFP_NOIO, &mddev->bio_set);
1640 			if (test_bit(CollisionCheck, &rdev->flags))
1641 				wait_for_serialization(rdev, r1_bio);
1642 			if (test_bit(WriteMostly, &rdev->flags))
1643 				atomic_inc(&r1_bio->behind_remaining);
1644 		} else {
1645 			mbio = bio_alloc_clone(rdev->bdev, bio, GFP_NOIO,
1646 					       &mddev->bio_set);
1647 
1648 			if (mddev->serialize_policy)
1649 				wait_for_serialization(rdev, r1_bio);
1650 		}
1651 
1652 		r1_bio->bios[i] = mbio;
1653 
1654 		mbio->bi_iter.bi_sector	= (r1_bio->sector + rdev->data_offset);
1655 		mbio->bi_end_io	= raid1_end_write_request;
1656 		if (test_bit(FailFast, &rdev->flags) &&
1657 		    !test_bit(WriteMostly, &rdev->flags) &&
1658 		    conf->raid_disks - mddev->degraded > 1)
1659 			mbio->bi_opf |= MD_FAILFAST;
1660 		mbio->bi_private = r1_bio;
1661 
1662 		atomic_inc(&r1_bio->remaining);
1663 		mddev_trace_remap(mddev, mbio, r1_bio->sector);
1664 		/* flush_pending_writes() needs access to the rdev so...*/
1665 		mbio->bi_bdev = (void *)rdev;
1666 		if (!raid1_add_bio_to_plug(mddev, mbio, raid1_unplug, disks)) {
1667 			spin_lock_irqsave(&conf->device_lock, flags);
1668 			bio_list_add(&conf->pending_bio_list, mbio);
1669 			spin_unlock_irqrestore(&conf->device_lock, flags);
1670 			md_wakeup_thread(mddev->thread);
1671 		}
1672 	}
1673 
1674 	r1_bio_write_done(r1_bio);
1675 
1676 	/* In case raid1d snuck in to freeze_array */
1677 	wake_up_barrier(conf);
1678 	return;
1679 err_handle:
1680 	for (k = 0; k < i; k++) {
1681 		if (r1_bio->bios[k]) {
1682 			rdev_dec_pending(conf->mirrors[k].rdev, mddev);
1683 			r1_bio->bios[k] = NULL;
1684 		}
1685 	}
1686 
1687 	bio->bi_status = errno_to_blk_status(error);
1688 	set_bit(R1BIO_Uptodate, &r1_bio->state);
1689 	raid_end_bio_io(r1_bio);
1690 }
1691 
raid1_make_request(struct mddev * mddev,struct bio * bio)1692 static bool raid1_make_request(struct mddev *mddev, struct bio *bio)
1693 {
1694 	sector_t sectors;
1695 
1696 	if (unlikely(bio->bi_opf & REQ_PREFLUSH)
1697 	    && md_flush_request(mddev, bio))
1698 		return true;
1699 
1700 	/*
1701 	 * There is a limit to the maximum size, but
1702 	 * the read/write handler might find a lower limit
1703 	 * due to bad blocks.  To avoid multiple splits,
1704 	 * we pass the maximum number of sectors down
1705 	 * and let the lower level perform the split.
1706 	 */
1707 	sectors = align_to_barrier_unit_end(
1708 		bio->bi_iter.bi_sector, bio_sectors(bio));
1709 
1710 	if (bio_data_dir(bio) == READ)
1711 		raid1_read_request(mddev, bio, sectors, NULL);
1712 	else {
1713 		md_write_start(mddev,bio);
1714 		raid1_write_request(mddev, bio, sectors);
1715 	}
1716 	return true;
1717 }
1718 
raid1_status(struct seq_file * seq,struct mddev * mddev)1719 static void raid1_status(struct seq_file *seq, struct mddev *mddev)
1720 {
1721 	struct r1conf *conf = mddev->private;
1722 	int i;
1723 
1724 	lockdep_assert_held(&mddev->lock);
1725 
1726 	seq_printf(seq, " [%d/%d] [", conf->raid_disks,
1727 		   conf->raid_disks - mddev->degraded);
1728 	for (i = 0; i < conf->raid_disks; i++) {
1729 		struct md_rdev *rdev = READ_ONCE(conf->mirrors[i].rdev);
1730 
1731 		seq_printf(seq, "%s",
1732 			   rdev && test_bit(In_sync, &rdev->flags) ? "U" : "_");
1733 	}
1734 	seq_printf(seq, "]");
1735 }
1736 
1737 /**
1738  * raid1_error() - RAID1 error handler.
1739  * @mddev: affected md device.
1740  * @rdev: member device to fail.
1741  *
1742  * The routine acknowledges &rdev failure and determines new @mddev state.
1743  * If it failed, then:
1744  *	- &MD_BROKEN flag is set in &mddev->flags.
1745  *	- recovery is disabled.
1746  * Otherwise, it must be degraded:
1747  *	- recovery is interrupted.
1748  *	- &mddev->degraded is bumped.
1749  *
1750  * @rdev is marked as &Faulty excluding case when array is failed and
1751  * &mddev->fail_last_dev is off.
1752  */
raid1_error(struct mddev * mddev,struct md_rdev * rdev)1753 static void raid1_error(struct mddev *mddev, struct md_rdev *rdev)
1754 {
1755 	struct r1conf *conf = mddev->private;
1756 	unsigned long flags;
1757 
1758 	spin_lock_irqsave(&conf->device_lock, flags);
1759 
1760 	if (test_bit(In_sync, &rdev->flags) &&
1761 	    (conf->raid_disks - mddev->degraded) == 1) {
1762 		set_bit(MD_BROKEN, &mddev->flags);
1763 
1764 		if (!mddev->fail_last_dev) {
1765 			conf->recovery_disabled = mddev->recovery_disabled;
1766 			spin_unlock_irqrestore(&conf->device_lock, flags);
1767 			return;
1768 		}
1769 	}
1770 	set_bit(Blocked, &rdev->flags);
1771 	if (test_and_clear_bit(In_sync, &rdev->flags))
1772 		mddev->degraded++;
1773 	set_bit(Faulty, &rdev->flags);
1774 	spin_unlock_irqrestore(&conf->device_lock, flags);
1775 	/*
1776 	 * if recovery is running, make sure it aborts.
1777 	 */
1778 	set_bit(MD_RECOVERY_INTR, &mddev->recovery);
1779 	set_mask_bits(&mddev->sb_flags, 0,
1780 		      BIT(MD_SB_CHANGE_DEVS) | BIT(MD_SB_CHANGE_PENDING));
1781 	pr_crit("md/raid1:%s: Disk failure on %pg, disabling device.\n"
1782 		"md/raid1:%s: Operation continuing on %d devices.\n",
1783 		mdname(mddev), rdev->bdev,
1784 		mdname(mddev), conf->raid_disks - mddev->degraded);
1785 }
1786 
print_conf(struct r1conf * conf)1787 static void print_conf(struct r1conf *conf)
1788 {
1789 	int i;
1790 
1791 	pr_debug("RAID1 conf printout:\n");
1792 	if (!conf) {
1793 		pr_debug("(!conf)\n");
1794 		return;
1795 	}
1796 	pr_debug(" --- wd:%d rd:%d\n", conf->raid_disks - conf->mddev->degraded,
1797 		 conf->raid_disks);
1798 
1799 	lockdep_assert_held(&conf->mddev->reconfig_mutex);
1800 	for (i = 0; i < conf->raid_disks; i++) {
1801 		struct md_rdev *rdev = conf->mirrors[i].rdev;
1802 		if (rdev)
1803 			pr_debug(" disk %d, wo:%d, o:%d, dev:%pg\n",
1804 				 i, !test_bit(In_sync, &rdev->flags),
1805 				 !test_bit(Faulty, &rdev->flags),
1806 				 rdev->bdev);
1807 	}
1808 }
1809 
close_sync(struct r1conf * conf)1810 static void close_sync(struct r1conf *conf)
1811 {
1812 	int idx;
1813 
1814 	for (idx = 0; idx < BARRIER_BUCKETS_NR; idx++) {
1815 		_wait_barrier(conf, idx, false);
1816 		_allow_barrier(conf, idx);
1817 	}
1818 
1819 	mempool_exit(&conf->r1buf_pool);
1820 }
1821 
raid1_spare_active(struct mddev * mddev)1822 static int raid1_spare_active(struct mddev *mddev)
1823 {
1824 	int i;
1825 	struct r1conf *conf = mddev->private;
1826 	int count = 0;
1827 	unsigned long flags;
1828 
1829 	/*
1830 	 * Find all failed disks within the RAID1 configuration
1831 	 * and mark them readable.
1832 	 * Called under mddev lock, so rcu protection not needed.
1833 	 * device_lock used to avoid races with raid1_end_read_request
1834 	 * which expects 'In_sync' flags and ->degraded to be consistent.
1835 	 */
1836 	spin_lock_irqsave(&conf->device_lock, flags);
1837 	for (i = 0; i < conf->raid_disks; i++) {
1838 		struct md_rdev *rdev = conf->mirrors[i].rdev;
1839 		struct md_rdev *repl = conf->mirrors[conf->raid_disks + i].rdev;
1840 		if (repl
1841 		    && !test_bit(Candidate, &repl->flags)
1842 		    && repl->recovery_offset == MaxSector
1843 		    && !test_bit(Faulty, &repl->flags)
1844 		    && !test_and_set_bit(In_sync, &repl->flags)) {
1845 			/* replacement has just become active */
1846 			if (!rdev ||
1847 			    !test_and_clear_bit(In_sync, &rdev->flags))
1848 				count++;
1849 			if (rdev) {
1850 				/* Replaced device not technically
1851 				 * faulty, but we need to be sure
1852 				 * it gets removed and never re-added
1853 				 */
1854 				set_bit(Faulty, &rdev->flags);
1855 				sysfs_notify_dirent_safe(
1856 					rdev->sysfs_state);
1857 			}
1858 		}
1859 		if (rdev
1860 		    && rdev->recovery_offset == MaxSector
1861 		    && !test_bit(Faulty, &rdev->flags)
1862 		    && !test_and_set_bit(In_sync, &rdev->flags)) {
1863 			count++;
1864 			sysfs_notify_dirent_safe(rdev->sysfs_state);
1865 		}
1866 	}
1867 	mddev->degraded -= count;
1868 	spin_unlock_irqrestore(&conf->device_lock, flags);
1869 
1870 	print_conf(conf);
1871 	return count;
1872 }
1873 
raid1_add_conf(struct r1conf * conf,struct md_rdev * rdev,int disk,bool replacement)1874 static bool raid1_add_conf(struct r1conf *conf, struct md_rdev *rdev, int disk,
1875 			   bool replacement)
1876 {
1877 	struct raid1_info *info = conf->mirrors + disk;
1878 
1879 	if (replacement)
1880 		info += conf->raid_disks;
1881 
1882 	if (info->rdev)
1883 		return false;
1884 
1885 	if (bdev_nonrot(rdev->bdev)) {
1886 		set_bit(Nonrot, &rdev->flags);
1887 		WRITE_ONCE(conf->nonrot_disks, conf->nonrot_disks + 1);
1888 	}
1889 
1890 	rdev->raid_disk = disk;
1891 	info->head_position = 0;
1892 	info->seq_start = MaxSector;
1893 	WRITE_ONCE(info->rdev, rdev);
1894 
1895 	return true;
1896 }
1897 
raid1_remove_conf(struct r1conf * conf,int disk)1898 static bool raid1_remove_conf(struct r1conf *conf, int disk)
1899 {
1900 	struct raid1_info *info = conf->mirrors + disk;
1901 	struct md_rdev *rdev = info->rdev;
1902 
1903 	if (!rdev || test_bit(In_sync, &rdev->flags) ||
1904 	    atomic_read(&rdev->nr_pending))
1905 		return false;
1906 
1907 	/* Only remove non-faulty devices if recovery is not possible. */
1908 	if (!test_bit(Faulty, &rdev->flags) &&
1909 	    rdev->mddev->recovery_disabled != conf->recovery_disabled &&
1910 	    rdev->mddev->degraded < conf->raid_disks)
1911 		return false;
1912 
1913 	if (test_and_clear_bit(Nonrot, &rdev->flags))
1914 		WRITE_ONCE(conf->nonrot_disks, conf->nonrot_disks - 1);
1915 
1916 	WRITE_ONCE(info->rdev, NULL);
1917 	return true;
1918 }
1919 
raid1_add_disk(struct mddev * mddev,struct md_rdev * rdev)1920 static int raid1_add_disk(struct mddev *mddev, struct md_rdev *rdev)
1921 {
1922 	struct r1conf *conf = mddev->private;
1923 	int err = -EEXIST;
1924 	int mirror = 0, repl_slot = -1;
1925 	struct raid1_info *p;
1926 	int first = 0;
1927 	int last = conf->raid_disks - 1;
1928 
1929 	if (mddev->recovery_disabled == conf->recovery_disabled)
1930 		return -EBUSY;
1931 
1932 	if (rdev->raid_disk >= 0)
1933 		first = last = rdev->raid_disk;
1934 
1935 	/*
1936 	 * find the disk ... but prefer rdev->saved_raid_disk
1937 	 * if possible.
1938 	 */
1939 	if (rdev->saved_raid_disk >= 0 &&
1940 	    rdev->saved_raid_disk >= first &&
1941 	    rdev->saved_raid_disk < conf->raid_disks &&
1942 	    conf->mirrors[rdev->saved_raid_disk].rdev == NULL)
1943 		first = last = rdev->saved_raid_disk;
1944 
1945 	for (mirror = first; mirror <= last; mirror++) {
1946 		p = conf->mirrors + mirror;
1947 		if (!p->rdev) {
1948 			err = mddev_stack_new_rdev(mddev, rdev);
1949 			if (err)
1950 				return err;
1951 
1952 			raid1_add_conf(conf, rdev, mirror, false);
1953 			/* As all devices are equivalent, we don't need a full recovery
1954 			 * if this was recently any drive of the array
1955 			 */
1956 			if (rdev->saved_raid_disk < 0)
1957 				conf->fullsync = 1;
1958 			break;
1959 		}
1960 		if (test_bit(WantReplacement, &p->rdev->flags) &&
1961 		    p[conf->raid_disks].rdev == NULL && repl_slot < 0)
1962 			repl_slot = mirror;
1963 	}
1964 
1965 	if (err && repl_slot >= 0) {
1966 		/* Add this device as a replacement */
1967 		clear_bit(In_sync, &rdev->flags);
1968 		set_bit(Replacement, &rdev->flags);
1969 		raid1_add_conf(conf, rdev, repl_slot, true);
1970 		err = 0;
1971 		conf->fullsync = 1;
1972 	}
1973 
1974 	print_conf(conf);
1975 	return err;
1976 }
1977 
raid1_remove_disk(struct mddev * mddev,struct md_rdev * rdev)1978 static int raid1_remove_disk(struct mddev *mddev, struct md_rdev *rdev)
1979 {
1980 	struct r1conf *conf = mddev->private;
1981 	int err = 0;
1982 	int number = rdev->raid_disk;
1983 	struct raid1_info *p = conf->mirrors + number;
1984 
1985 	if (unlikely(number >= conf->raid_disks))
1986 		goto abort;
1987 
1988 	if (rdev != p->rdev) {
1989 		number += conf->raid_disks;
1990 		p = conf->mirrors + number;
1991 	}
1992 
1993 	print_conf(conf);
1994 	if (rdev == p->rdev) {
1995 		if (!raid1_remove_conf(conf, number)) {
1996 			err = -EBUSY;
1997 			goto abort;
1998 		}
1999 
2000 		if (number < conf->raid_disks &&
2001 		    conf->mirrors[conf->raid_disks + number].rdev) {
2002 			/* We just removed a device that is being replaced.
2003 			 * Move down the replacement.  We drain all IO before
2004 			 * doing this to avoid confusion.
2005 			 */
2006 			struct md_rdev *repl =
2007 				conf->mirrors[conf->raid_disks + number].rdev;
2008 			freeze_array(conf, 0);
2009 			if (atomic_read(&repl->nr_pending)) {
2010 				/* It means that some queued IO of retry_list
2011 				 * hold repl. Thus, we cannot set replacement
2012 				 * as NULL, avoiding rdev NULL pointer
2013 				 * dereference in sync_request_write and
2014 				 * handle_write_finished.
2015 				 */
2016 				err = -EBUSY;
2017 				unfreeze_array(conf);
2018 				goto abort;
2019 			}
2020 			clear_bit(Replacement, &repl->flags);
2021 			WRITE_ONCE(p->rdev, repl);
2022 			conf->mirrors[conf->raid_disks + number].rdev = NULL;
2023 			unfreeze_array(conf);
2024 		}
2025 
2026 		clear_bit(WantReplacement, &rdev->flags);
2027 		err = md_integrity_register(mddev);
2028 	}
2029 abort:
2030 
2031 	print_conf(conf);
2032 	return err;
2033 }
2034 
end_sync_read(struct bio * bio)2035 static void end_sync_read(struct bio *bio)
2036 {
2037 	struct r1bio *r1_bio = get_resync_r1bio(bio);
2038 
2039 	update_head_pos(r1_bio->read_disk, r1_bio);
2040 
2041 	/*
2042 	 * we have read a block, now it needs to be re-written,
2043 	 * or re-read if the read failed.
2044 	 * We don't do much here, just schedule handling by raid1d
2045 	 */
2046 	if (!bio->bi_status)
2047 		set_bit(R1BIO_Uptodate, &r1_bio->state);
2048 
2049 	if (atomic_dec_and_test(&r1_bio->remaining))
2050 		reschedule_retry(r1_bio);
2051 }
2052 
abort_sync_write(struct mddev * mddev,struct r1bio * r1_bio)2053 static void abort_sync_write(struct mddev *mddev, struct r1bio *r1_bio)
2054 {
2055 	sector_t sync_blocks = 0;
2056 	sector_t s = r1_bio->sector;
2057 	long sectors_to_go = r1_bio->sectors;
2058 
2059 	/* make sure these bits don't get cleared. */
2060 	do {
2061 		mddev->bitmap_ops->end_sync(mddev, s, &sync_blocks);
2062 		s += sync_blocks;
2063 		sectors_to_go -= sync_blocks;
2064 	} while (sectors_to_go > 0);
2065 }
2066 
put_sync_write_buf(struct r1bio * r1_bio,int uptodate)2067 static void put_sync_write_buf(struct r1bio *r1_bio, int uptodate)
2068 {
2069 	if (atomic_dec_and_test(&r1_bio->remaining)) {
2070 		struct mddev *mddev = r1_bio->mddev;
2071 		int s = r1_bio->sectors;
2072 
2073 		if (test_bit(R1BIO_MadeGood, &r1_bio->state) ||
2074 		    test_bit(R1BIO_WriteError, &r1_bio->state))
2075 			reschedule_retry(r1_bio);
2076 		else {
2077 			put_buf(r1_bio);
2078 			md_done_sync(mddev, s, uptodate);
2079 		}
2080 	}
2081 }
2082 
end_sync_write(struct bio * bio)2083 static void end_sync_write(struct bio *bio)
2084 {
2085 	int uptodate = !bio->bi_status;
2086 	struct r1bio *r1_bio = get_resync_r1bio(bio);
2087 	struct mddev *mddev = r1_bio->mddev;
2088 	struct r1conf *conf = mddev->private;
2089 	struct md_rdev *rdev = conf->mirrors[find_bio_disk(r1_bio, bio)].rdev;
2090 
2091 	if (!uptodate) {
2092 		abort_sync_write(mddev, r1_bio);
2093 		set_bit(WriteErrorSeen, &rdev->flags);
2094 		if (!test_and_set_bit(WantReplacement, &rdev->flags))
2095 			set_bit(MD_RECOVERY_NEEDED, &
2096 				mddev->recovery);
2097 		set_bit(R1BIO_WriteError, &r1_bio->state);
2098 	} else if (rdev_has_badblock(rdev, r1_bio->sector, r1_bio->sectors) &&
2099 		   !rdev_has_badblock(conf->mirrors[r1_bio->read_disk].rdev,
2100 				      r1_bio->sector, r1_bio->sectors)) {
2101 		set_bit(R1BIO_MadeGood, &r1_bio->state);
2102 	}
2103 
2104 	put_sync_write_buf(r1_bio, uptodate);
2105 }
2106 
r1_sync_page_io(struct md_rdev * rdev,sector_t sector,int sectors,struct page * page,blk_opf_t rw)2107 static int r1_sync_page_io(struct md_rdev *rdev, sector_t sector,
2108 			   int sectors, struct page *page, blk_opf_t rw)
2109 {
2110 	if (sync_page_io(rdev, sector, sectors << 9, page, rw, false))
2111 		/* success */
2112 		return 1;
2113 	if (rw == REQ_OP_WRITE) {
2114 		set_bit(WriteErrorSeen, &rdev->flags);
2115 		if (!test_and_set_bit(WantReplacement,
2116 				      &rdev->flags))
2117 			set_bit(MD_RECOVERY_NEEDED, &
2118 				rdev->mddev->recovery);
2119 	}
2120 	/* need to record an error - either for the block or the device */
2121 	if (!rdev_set_badblocks(rdev, sector, sectors, 0))
2122 		md_error(rdev->mddev, rdev);
2123 	return 0;
2124 }
2125 
fix_sync_read_error(struct r1bio * r1_bio)2126 static int fix_sync_read_error(struct r1bio *r1_bio)
2127 {
2128 	/* Try some synchronous reads of other devices to get
2129 	 * good data, much like with normal read errors.  Only
2130 	 * read into the pages we already have so we don't
2131 	 * need to re-issue the read request.
2132 	 * We don't need to freeze the array, because being in an
2133 	 * active sync request, there is no normal IO, and
2134 	 * no overlapping syncs.
2135 	 * We don't need to check is_badblock() again as we
2136 	 * made sure that anything with a bad block in range
2137 	 * will have bi_end_io clear.
2138 	 */
2139 	struct mddev *mddev = r1_bio->mddev;
2140 	struct r1conf *conf = mddev->private;
2141 	struct bio *bio = r1_bio->bios[r1_bio->read_disk];
2142 	struct page **pages = get_resync_pages(bio)->pages;
2143 	sector_t sect = r1_bio->sector;
2144 	int sectors = r1_bio->sectors;
2145 	int idx = 0;
2146 	struct md_rdev *rdev;
2147 
2148 	rdev = conf->mirrors[r1_bio->read_disk].rdev;
2149 	if (test_bit(FailFast, &rdev->flags)) {
2150 		/* Don't try recovering from here - just fail it
2151 		 * ... unless it is the last working device of course */
2152 		md_error(mddev, rdev);
2153 		if (test_bit(Faulty, &rdev->flags))
2154 			/* Don't try to read from here, but make sure
2155 			 * put_buf does it's thing
2156 			 */
2157 			bio->bi_end_io = end_sync_write;
2158 	}
2159 
2160 	while(sectors) {
2161 		int s = sectors;
2162 		int d = r1_bio->read_disk;
2163 		int success = 0;
2164 		int start;
2165 
2166 		if (s > (PAGE_SIZE>>9))
2167 			s = PAGE_SIZE >> 9;
2168 		do {
2169 			if (r1_bio->bios[d]->bi_end_io == end_sync_read) {
2170 				/* No rcu protection needed here devices
2171 				 * can only be removed when no resync is
2172 				 * active, and resync is currently active
2173 				 */
2174 				rdev = conf->mirrors[d].rdev;
2175 				if (sync_page_io(rdev, sect, s<<9,
2176 						 pages[idx],
2177 						 REQ_OP_READ, false)) {
2178 					success = 1;
2179 					break;
2180 				}
2181 			}
2182 			d++;
2183 			if (d == conf->raid_disks * 2)
2184 				d = 0;
2185 		} while (!success && d != r1_bio->read_disk);
2186 
2187 		if (!success) {
2188 			int abort = 0;
2189 			/* Cannot read from anywhere, this block is lost.
2190 			 * Record a bad block on each device.  If that doesn't
2191 			 * work just disable and interrupt the recovery.
2192 			 * Don't fail devices as that won't really help.
2193 			 */
2194 			pr_crit_ratelimited("md/raid1:%s: %pg: unrecoverable I/O read error for block %llu\n",
2195 					    mdname(mddev), bio->bi_bdev,
2196 					    (unsigned long long)r1_bio->sector);
2197 			for (d = 0; d < conf->raid_disks * 2; d++) {
2198 				rdev = conf->mirrors[d].rdev;
2199 				if (!rdev || test_bit(Faulty, &rdev->flags))
2200 					continue;
2201 				if (!rdev_set_badblocks(rdev, sect, s, 0))
2202 					abort = 1;
2203 			}
2204 			if (abort)
2205 				return 0;
2206 
2207 			/* Try next page */
2208 			sectors -= s;
2209 			sect += s;
2210 			idx++;
2211 			continue;
2212 		}
2213 
2214 		start = d;
2215 		/* write it back and re-read */
2216 		while (d != r1_bio->read_disk) {
2217 			if (d == 0)
2218 				d = conf->raid_disks * 2;
2219 			d--;
2220 			if (r1_bio->bios[d]->bi_end_io != end_sync_read)
2221 				continue;
2222 			rdev = conf->mirrors[d].rdev;
2223 			if (r1_sync_page_io(rdev, sect, s,
2224 					    pages[idx],
2225 					    REQ_OP_WRITE) == 0) {
2226 				r1_bio->bios[d]->bi_end_io = NULL;
2227 				rdev_dec_pending(rdev, mddev);
2228 			}
2229 		}
2230 		d = start;
2231 		while (d != r1_bio->read_disk) {
2232 			if (d == 0)
2233 				d = conf->raid_disks * 2;
2234 			d--;
2235 			if (r1_bio->bios[d]->bi_end_io != end_sync_read)
2236 				continue;
2237 			rdev = conf->mirrors[d].rdev;
2238 			if (r1_sync_page_io(rdev, sect, s,
2239 					    pages[idx],
2240 					    REQ_OP_READ) != 0)
2241 				atomic_add(s, &rdev->corrected_errors);
2242 		}
2243 		sectors -= s;
2244 		sect += s;
2245 		idx ++;
2246 	}
2247 	set_bit(R1BIO_Uptodate, &r1_bio->state);
2248 	bio->bi_status = 0;
2249 	return 1;
2250 }
2251 
process_checks(struct r1bio * r1_bio)2252 static void process_checks(struct r1bio *r1_bio)
2253 {
2254 	/* We have read all readable devices.  If we haven't
2255 	 * got the block, then there is no hope left.
2256 	 * If we have, then we want to do a comparison
2257 	 * and skip the write if everything is the same.
2258 	 * If any blocks failed to read, then we need to
2259 	 * attempt an over-write
2260 	 */
2261 	struct mddev *mddev = r1_bio->mddev;
2262 	struct r1conf *conf = mddev->private;
2263 	int primary;
2264 	int i;
2265 	int vcnt;
2266 
2267 	/* Fix variable parts of all bios */
2268 	vcnt = (r1_bio->sectors + PAGE_SIZE / 512 - 1) >> (PAGE_SHIFT - 9);
2269 	for (i = 0; i < conf->raid_disks * 2; i++) {
2270 		blk_status_t status;
2271 		struct bio *b = r1_bio->bios[i];
2272 		struct resync_pages *rp = get_resync_pages(b);
2273 		if (b->bi_end_io != end_sync_read)
2274 			continue;
2275 		/* fixup the bio for reuse, but preserve errno */
2276 		status = b->bi_status;
2277 		bio_reset(b, conf->mirrors[i].rdev->bdev, REQ_OP_READ);
2278 		b->bi_status = status;
2279 		b->bi_iter.bi_sector = r1_bio->sector +
2280 			conf->mirrors[i].rdev->data_offset;
2281 		b->bi_end_io = end_sync_read;
2282 		rp->raid_bio = r1_bio;
2283 		b->bi_private = rp;
2284 
2285 		/* initialize bvec table again */
2286 		md_bio_reset_resync_pages(b, rp, r1_bio->sectors << 9);
2287 	}
2288 	for (primary = 0; primary < conf->raid_disks * 2; primary++)
2289 		if (r1_bio->bios[primary]->bi_end_io == end_sync_read &&
2290 		    !r1_bio->bios[primary]->bi_status) {
2291 			r1_bio->bios[primary]->bi_end_io = NULL;
2292 			rdev_dec_pending(conf->mirrors[primary].rdev, mddev);
2293 			break;
2294 		}
2295 	r1_bio->read_disk = primary;
2296 	for (i = 0; i < conf->raid_disks * 2; i++) {
2297 		int j = 0;
2298 		struct bio *pbio = r1_bio->bios[primary];
2299 		struct bio *sbio = r1_bio->bios[i];
2300 		blk_status_t status = sbio->bi_status;
2301 		struct page **ppages = get_resync_pages(pbio)->pages;
2302 		struct page **spages = get_resync_pages(sbio)->pages;
2303 		struct bio_vec *bi;
2304 		int page_len[RESYNC_PAGES] = { 0 };
2305 		struct bvec_iter_all iter_all;
2306 
2307 		if (sbio->bi_end_io != end_sync_read)
2308 			continue;
2309 		/* Now we can 'fixup' the error value */
2310 		sbio->bi_status = 0;
2311 
2312 		bio_for_each_segment_all(bi, sbio, iter_all)
2313 			page_len[j++] = bi->bv_len;
2314 
2315 		if (!status) {
2316 			for (j = vcnt; j-- ; ) {
2317 				if (memcmp(page_address(ppages[j]),
2318 					   page_address(spages[j]),
2319 					   page_len[j]))
2320 					break;
2321 			}
2322 		} else
2323 			j = 0;
2324 		if (j >= 0)
2325 			atomic64_add(r1_bio->sectors, &mddev->resync_mismatches);
2326 		if (j < 0 || (test_bit(MD_RECOVERY_CHECK, &mddev->recovery)
2327 			      && !status)) {
2328 			/* No need to write to this device. */
2329 			sbio->bi_end_io = NULL;
2330 			rdev_dec_pending(conf->mirrors[i].rdev, mddev);
2331 			continue;
2332 		}
2333 
2334 		bio_copy_data(sbio, pbio);
2335 	}
2336 }
2337 
sync_request_write(struct mddev * mddev,struct r1bio * r1_bio)2338 static void sync_request_write(struct mddev *mddev, struct r1bio *r1_bio)
2339 {
2340 	struct r1conf *conf = mddev->private;
2341 	int i;
2342 	int disks = conf->raid_disks * 2;
2343 	struct bio *wbio;
2344 
2345 	if (!test_bit(R1BIO_Uptodate, &r1_bio->state)) {
2346 		/*
2347 		 * ouch - failed to read all of that.
2348 		 * No need to fix read error for check/repair
2349 		 * because all member disks are read.
2350 		 */
2351 		if (test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery) ||
2352 		    !fix_sync_read_error(r1_bio)) {
2353 			conf->recovery_disabled = mddev->recovery_disabled;
2354 			set_bit(MD_RECOVERY_INTR, &mddev->recovery);
2355 			md_done_sync(mddev, r1_bio->sectors, 0);
2356 			put_buf(r1_bio);
2357 			return;
2358 		}
2359 	}
2360 
2361 	if (test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery))
2362 		process_checks(r1_bio);
2363 
2364 	/*
2365 	 * schedule writes
2366 	 */
2367 	atomic_set(&r1_bio->remaining, 1);
2368 	for (i = 0; i < disks ; i++) {
2369 		wbio = r1_bio->bios[i];
2370 		if (wbio->bi_end_io == NULL ||
2371 		    (wbio->bi_end_io == end_sync_read &&
2372 		     (i == r1_bio->read_disk ||
2373 		      !test_bit(MD_RECOVERY_SYNC, &mddev->recovery))))
2374 			continue;
2375 		if (test_bit(Faulty, &conf->mirrors[i].rdev->flags)) {
2376 			abort_sync_write(mddev, r1_bio);
2377 			continue;
2378 		}
2379 
2380 		wbio->bi_opf = REQ_OP_WRITE;
2381 		if (test_bit(FailFast, &conf->mirrors[i].rdev->flags))
2382 			wbio->bi_opf |= MD_FAILFAST;
2383 
2384 		wbio->bi_end_io = end_sync_write;
2385 		atomic_inc(&r1_bio->remaining);
2386 
2387 		submit_bio_noacct(wbio);
2388 	}
2389 
2390 	put_sync_write_buf(r1_bio, 1);
2391 }
2392 
2393 /*
2394  * This is a kernel thread which:
2395  *
2396  *	1.	Retries failed read operations on working mirrors.
2397  *	2.	Updates the raid superblock when problems encounter.
2398  *	3.	Performs writes following reads for array synchronising.
2399  */
2400 
fix_read_error(struct r1conf * conf,struct r1bio * r1_bio)2401 static void fix_read_error(struct r1conf *conf, struct r1bio *r1_bio)
2402 {
2403 	sector_t sect = r1_bio->sector;
2404 	int sectors = r1_bio->sectors;
2405 	int read_disk = r1_bio->read_disk;
2406 	struct mddev *mddev = conf->mddev;
2407 	struct md_rdev *rdev = conf->mirrors[read_disk].rdev;
2408 
2409 	if (exceed_read_errors(mddev, rdev)) {
2410 		r1_bio->bios[r1_bio->read_disk] = IO_BLOCKED;
2411 		return;
2412 	}
2413 
2414 	while(sectors) {
2415 		int s = sectors;
2416 		int d = read_disk;
2417 		int success = 0;
2418 		int start;
2419 
2420 		if (s > (PAGE_SIZE>>9))
2421 			s = PAGE_SIZE >> 9;
2422 
2423 		do {
2424 			rdev = conf->mirrors[d].rdev;
2425 			if (rdev &&
2426 			    (test_bit(In_sync, &rdev->flags) ||
2427 			     (!test_bit(Faulty, &rdev->flags) &&
2428 			      rdev->recovery_offset >= sect + s)) &&
2429 			    rdev_has_badblock(rdev, sect, s) == 0) {
2430 				atomic_inc(&rdev->nr_pending);
2431 				if (sync_page_io(rdev, sect, s<<9,
2432 					 conf->tmppage, REQ_OP_READ, false))
2433 					success = 1;
2434 				rdev_dec_pending(rdev, mddev);
2435 				if (success)
2436 					break;
2437 			}
2438 
2439 			d++;
2440 			if (d == conf->raid_disks * 2)
2441 				d = 0;
2442 		} while (d != read_disk);
2443 
2444 		if (!success) {
2445 			/* Cannot read from anywhere - mark it bad */
2446 			struct md_rdev *rdev = conf->mirrors[read_disk].rdev;
2447 			if (!rdev_set_badblocks(rdev, sect, s, 0))
2448 				md_error(mddev, rdev);
2449 			break;
2450 		}
2451 		/* write it back and re-read */
2452 		start = d;
2453 		while (d != read_disk) {
2454 			if (d==0)
2455 				d = conf->raid_disks * 2;
2456 			d--;
2457 			rdev = conf->mirrors[d].rdev;
2458 			if (rdev &&
2459 			    !test_bit(Faulty, &rdev->flags)) {
2460 				atomic_inc(&rdev->nr_pending);
2461 				r1_sync_page_io(rdev, sect, s,
2462 						conf->tmppage, REQ_OP_WRITE);
2463 				rdev_dec_pending(rdev, mddev);
2464 			}
2465 		}
2466 		d = start;
2467 		while (d != read_disk) {
2468 			if (d==0)
2469 				d = conf->raid_disks * 2;
2470 			d--;
2471 			rdev = conf->mirrors[d].rdev;
2472 			if (rdev &&
2473 			    !test_bit(Faulty, &rdev->flags)) {
2474 				atomic_inc(&rdev->nr_pending);
2475 				if (r1_sync_page_io(rdev, sect, s,
2476 						conf->tmppage, REQ_OP_READ)) {
2477 					atomic_add(s, &rdev->corrected_errors);
2478 					pr_info("md/raid1:%s: read error corrected (%d sectors at %llu on %pg)\n",
2479 						mdname(mddev), s,
2480 						(unsigned long long)(sect +
2481 								     rdev->data_offset),
2482 						rdev->bdev);
2483 				}
2484 				rdev_dec_pending(rdev, mddev);
2485 			}
2486 		}
2487 		sectors -= s;
2488 		sect += s;
2489 	}
2490 }
2491 
narrow_write_error(struct r1bio * r1_bio,int i)2492 static bool narrow_write_error(struct r1bio *r1_bio, int i)
2493 {
2494 	struct mddev *mddev = r1_bio->mddev;
2495 	struct r1conf *conf = mddev->private;
2496 	struct md_rdev *rdev = conf->mirrors[i].rdev;
2497 
2498 	/* bio has the data to be written to device 'i' where
2499 	 * we just recently had a write error.
2500 	 * We repeatedly clone the bio and trim down to one block,
2501 	 * then try the write.  Where the write fails we record
2502 	 * a bad block.
2503 	 * It is conceivable that the bio doesn't exactly align with
2504 	 * blocks.  We must handle this somehow.
2505 	 *
2506 	 * We currently own a reference on the rdev.
2507 	 */
2508 
2509 	int block_sectors;
2510 	sector_t sector;
2511 	int sectors;
2512 	int sect_to_write = r1_bio->sectors;
2513 	bool ok = true;
2514 
2515 	if (rdev->badblocks.shift < 0)
2516 		return false;
2517 
2518 	block_sectors = roundup(1 << rdev->badblocks.shift,
2519 				bdev_logical_block_size(rdev->bdev) >> 9);
2520 	sector = r1_bio->sector;
2521 	sectors = ((sector + block_sectors)
2522 		   & ~(sector_t)(block_sectors - 1))
2523 		- sector;
2524 
2525 	while (sect_to_write) {
2526 		struct bio *wbio;
2527 		if (sectors > sect_to_write)
2528 			sectors = sect_to_write;
2529 		/* Write at 'sector' for 'sectors'*/
2530 
2531 		if (test_bit(R1BIO_BehindIO, &r1_bio->state)) {
2532 			wbio = bio_alloc_clone(rdev->bdev,
2533 					       r1_bio->behind_master_bio,
2534 					       GFP_NOIO, &mddev->bio_set);
2535 		} else {
2536 			wbio = bio_alloc_clone(rdev->bdev, r1_bio->master_bio,
2537 					       GFP_NOIO, &mddev->bio_set);
2538 		}
2539 
2540 		wbio->bi_opf = REQ_OP_WRITE;
2541 		wbio->bi_iter.bi_sector = r1_bio->sector;
2542 		wbio->bi_iter.bi_size = r1_bio->sectors << 9;
2543 
2544 		bio_trim(wbio, sector - r1_bio->sector, sectors);
2545 		wbio->bi_iter.bi_sector += rdev->data_offset;
2546 
2547 		if (submit_bio_wait(wbio) < 0)
2548 			/* failure! */
2549 			ok = rdev_set_badblocks(rdev, sector,
2550 						sectors, 0)
2551 				&& ok;
2552 
2553 		bio_put(wbio);
2554 		sect_to_write -= sectors;
2555 		sector += sectors;
2556 		sectors = block_sectors;
2557 	}
2558 	return ok;
2559 }
2560 
handle_sync_write_finished(struct r1conf * conf,struct r1bio * r1_bio)2561 static void handle_sync_write_finished(struct r1conf *conf, struct r1bio *r1_bio)
2562 {
2563 	int m;
2564 	int s = r1_bio->sectors;
2565 	for (m = 0; m < conf->raid_disks * 2 ; m++) {
2566 		struct md_rdev *rdev = conf->mirrors[m].rdev;
2567 		struct bio *bio = r1_bio->bios[m];
2568 		if (bio->bi_end_io == NULL)
2569 			continue;
2570 		if (!bio->bi_status &&
2571 		    test_bit(R1BIO_MadeGood, &r1_bio->state)) {
2572 			rdev_clear_badblocks(rdev, r1_bio->sector, s, 0);
2573 		}
2574 		if (bio->bi_status &&
2575 		    test_bit(R1BIO_WriteError, &r1_bio->state)) {
2576 			if (!rdev_set_badblocks(rdev, r1_bio->sector, s, 0))
2577 				md_error(conf->mddev, rdev);
2578 		}
2579 	}
2580 	put_buf(r1_bio);
2581 	md_done_sync(conf->mddev, s, 1);
2582 }
2583 
handle_write_finished(struct r1conf * conf,struct r1bio * r1_bio)2584 static void handle_write_finished(struct r1conf *conf, struct r1bio *r1_bio)
2585 {
2586 	int m, idx;
2587 	bool fail = false;
2588 
2589 	for (m = 0; m < conf->raid_disks * 2 ; m++)
2590 		if (r1_bio->bios[m] == IO_MADE_GOOD) {
2591 			struct md_rdev *rdev = conf->mirrors[m].rdev;
2592 			rdev_clear_badblocks(rdev,
2593 					     r1_bio->sector,
2594 					     r1_bio->sectors, 0);
2595 			rdev_dec_pending(rdev, conf->mddev);
2596 		} else if (r1_bio->bios[m] != NULL) {
2597 			/* This drive got a write error.  We need to
2598 			 * narrow down and record precise write
2599 			 * errors.
2600 			 */
2601 			fail = true;
2602 			if (!narrow_write_error(r1_bio, m))
2603 				md_error(conf->mddev,
2604 					 conf->mirrors[m].rdev);
2605 				/* an I/O failed, we can't clear the bitmap */
2606 			rdev_dec_pending(conf->mirrors[m].rdev,
2607 					 conf->mddev);
2608 		}
2609 	if (fail) {
2610 		spin_lock_irq(&conf->device_lock);
2611 		list_add(&r1_bio->retry_list, &conf->bio_end_io_list);
2612 		idx = sector_to_idx(r1_bio->sector);
2613 		atomic_inc(&conf->nr_queued[idx]);
2614 		spin_unlock_irq(&conf->device_lock);
2615 		/*
2616 		 * In case freeze_array() is waiting for condition
2617 		 * get_unqueued_pending() == extra to be true.
2618 		 */
2619 		wake_up(&conf->wait_barrier);
2620 		md_wakeup_thread(conf->mddev->thread);
2621 	} else {
2622 		if (test_bit(R1BIO_WriteError, &r1_bio->state))
2623 			close_write(r1_bio);
2624 		raid_end_bio_io(r1_bio);
2625 	}
2626 }
2627 
handle_read_error(struct r1conf * conf,struct r1bio * r1_bio)2628 static void handle_read_error(struct r1conf *conf, struct r1bio *r1_bio)
2629 {
2630 	struct mddev *mddev = conf->mddev;
2631 	struct bio *bio;
2632 	struct md_rdev *rdev;
2633 	sector_t sector;
2634 
2635 	clear_bit(R1BIO_ReadError, &r1_bio->state);
2636 	/* we got a read error. Maybe the drive is bad.  Maybe just
2637 	 * the block and we can fix it.
2638 	 * We freeze all other IO, and try reading the block from
2639 	 * other devices.  When we find one, we re-write
2640 	 * and check it that fixes the read error.
2641 	 * This is all done synchronously while the array is
2642 	 * frozen
2643 	 */
2644 
2645 	bio = r1_bio->bios[r1_bio->read_disk];
2646 	bio_put(bio);
2647 	r1_bio->bios[r1_bio->read_disk] = NULL;
2648 
2649 	rdev = conf->mirrors[r1_bio->read_disk].rdev;
2650 	if (mddev->ro == 0
2651 	    && !test_bit(FailFast, &rdev->flags)) {
2652 		freeze_array(conf, 1);
2653 		fix_read_error(conf, r1_bio);
2654 		unfreeze_array(conf);
2655 	} else if (mddev->ro == 0 && test_bit(FailFast, &rdev->flags)) {
2656 		md_error(mddev, rdev);
2657 	} else {
2658 		r1_bio->bios[r1_bio->read_disk] = IO_BLOCKED;
2659 	}
2660 
2661 	rdev_dec_pending(rdev, conf->mddev);
2662 	sector = r1_bio->sector;
2663 	bio = r1_bio->master_bio;
2664 
2665 	/* Reuse the old r1_bio so that the IO_BLOCKED settings are preserved */
2666 	r1_bio->state = 0;
2667 	raid1_read_request(mddev, bio, r1_bio->sectors, r1_bio);
2668 	allow_barrier(conf, sector);
2669 }
2670 
raid1d(struct md_thread * thread)2671 static void raid1d(struct md_thread *thread)
2672 {
2673 	struct mddev *mddev = thread->mddev;
2674 	struct r1bio *r1_bio;
2675 	unsigned long flags;
2676 	struct r1conf *conf = mddev->private;
2677 	struct list_head *head = &conf->retry_list;
2678 	struct blk_plug plug;
2679 	int idx;
2680 
2681 	md_check_recovery(mddev);
2682 
2683 	if (!list_empty_careful(&conf->bio_end_io_list) &&
2684 	    !test_bit(MD_SB_CHANGE_PENDING, &mddev->sb_flags)) {
2685 		LIST_HEAD(tmp);
2686 		spin_lock_irqsave(&conf->device_lock, flags);
2687 		if (!test_bit(MD_SB_CHANGE_PENDING, &mddev->sb_flags))
2688 			list_splice_init(&conf->bio_end_io_list, &tmp);
2689 		spin_unlock_irqrestore(&conf->device_lock, flags);
2690 		while (!list_empty(&tmp)) {
2691 			r1_bio = list_first_entry(&tmp, struct r1bio,
2692 						  retry_list);
2693 			list_del(&r1_bio->retry_list);
2694 			idx = sector_to_idx(r1_bio->sector);
2695 			atomic_dec(&conf->nr_queued[idx]);
2696 			if (test_bit(R1BIO_WriteError, &r1_bio->state))
2697 				close_write(r1_bio);
2698 			raid_end_bio_io(r1_bio);
2699 		}
2700 	}
2701 
2702 	blk_start_plug(&plug);
2703 	for (;;) {
2704 
2705 		flush_pending_writes(conf);
2706 
2707 		spin_lock_irqsave(&conf->device_lock, flags);
2708 		if (list_empty(head)) {
2709 			spin_unlock_irqrestore(&conf->device_lock, flags);
2710 			break;
2711 		}
2712 		r1_bio = list_entry(head->prev, struct r1bio, retry_list);
2713 		list_del(head->prev);
2714 		idx = sector_to_idx(r1_bio->sector);
2715 		atomic_dec(&conf->nr_queued[idx]);
2716 		spin_unlock_irqrestore(&conf->device_lock, flags);
2717 
2718 		mddev = r1_bio->mddev;
2719 		conf = mddev->private;
2720 		if (test_bit(R1BIO_IsSync, &r1_bio->state)) {
2721 			if (test_bit(R1BIO_MadeGood, &r1_bio->state) ||
2722 			    test_bit(R1BIO_WriteError, &r1_bio->state))
2723 				handle_sync_write_finished(conf, r1_bio);
2724 			else
2725 				sync_request_write(mddev, r1_bio);
2726 		} else if (test_bit(R1BIO_MadeGood, &r1_bio->state) ||
2727 			   test_bit(R1BIO_WriteError, &r1_bio->state))
2728 			handle_write_finished(conf, r1_bio);
2729 		else if (test_bit(R1BIO_ReadError, &r1_bio->state))
2730 			handle_read_error(conf, r1_bio);
2731 		else
2732 			WARN_ON_ONCE(1);
2733 
2734 		cond_resched();
2735 		if (mddev->sb_flags & ~(1<<MD_SB_CHANGE_PENDING))
2736 			md_check_recovery(mddev);
2737 	}
2738 	blk_finish_plug(&plug);
2739 }
2740 
init_resync(struct r1conf * conf)2741 static int init_resync(struct r1conf *conf)
2742 {
2743 	int buffs;
2744 
2745 	buffs = RESYNC_WINDOW / RESYNC_BLOCK_SIZE;
2746 	BUG_ON(mempool_initialized(&conf->r1buf_pool));
2747 
2748 	return mempool_init(&conf->r1buf_pool, buffs, r1buf_pool_alloc,
2749 			    r1buf_pool_free, conf->poolinfo);
2750 }
2751 
raid1_alloc_init_r1buf(struct r1conf * conf)2752 static struct r1bio *raid1_alloc_init_r1buf(struct r1conf *conf)
2753 {
2754 	struct r1bio *r1bio = mempool_alloc(&conf->r1buf_pool, GFP_NOIO);
2755 	struct resync_pages *rps;
2756 	struct bio *bio;
2757 	int i;
2758 
2759 	for (i = conf->poolinfo->raid_disks; i--; ) {
2760 		bio = r1bio->bios[i];
2761 		rps = bio->bi_private;
2762 		bio_reset(bio, NULL, 0);
2763 		bio->bi_private = rps;
2764 	}
2765 	r1bio->master_bio = NULL;
2766 	return r1bio;
2767 }
2768 
2769 /*
2770  * perform a "sync" on one "block"
2771  *
2772  * We need to make sure that no normal I/O request - particularly write
2773  * requests - conflict with active sync requests.
2774  *
2775  * This is achieved by tracking pending requests and a 'barrier' concept
2776  * that can be installed to exclude normal IO requests.
2777  */
2778 
raid1_sync_request(struct mddev * mddev,sector_t sector_nr,sector_t max_sector,int * skipped)2779 static sector_t raid1_sync_request(struct mddev *mddev, sector_t sector_nr,
2780 				   sector_t max_sector, int *skipped)
2781 {
2782 	struct r1conf *conf = mddev->private;
2783 	struct r1bio *r1_bio;
2784 	struct bio *bio;
2785 	sector_t nr_sectors;
2786 	int disk = -1;
2787 	int i;
2788 	int wonly = -1;
2789 	int write_targets = 0, read_targets = 0;
2790 	sector_t sync_blocks;
2791 	bool still_degraded = false;
2792 	int good_sectors = RESYNC_SECTORS;
2793 	int min_bad = 0; /* number of sectors that are bad in all devices */
2794 	int idx = sector_to_idx(sector_nr);
2795 	int page_idx = 0;
2796 
2797 	if (!mempool_initialized(&conf->r1buf_pool))
2798 		if (init_resync(conf))
2799 			return 0;
2800 
2801 	if (sector_nr >= max_sector) {
2802 		/* If we aborted, we need to abort the
2803 		 * sync on the 'current' bitmap chunk (there will
2804 		 * only be one in raid1 resync.
2805 		 * We can find the current addess in mddev->curr_resync
2806 		 */
2807 		if (mddev->curr_resync < max_sector) /* aborted */
2808 			mddev->bitmap_ops->end_sync(mddev, mddev->curr_resync,
2809 						    &sync_blocks);
2810 		else /* completed sync */
2811 			conf->fullsync = 0;
2812 
2813 		mddev->bitmap_ops->close_sync(mddev);
2814 		close_sync(conf);
2815 
2816 		if (mddev_is_clustered(mddev)) {
2817 			conf->cluster_sync_low = 0;
2818 			conf->cluster_sync_high = 0;
2819 		}
2820 		return 0;
2821 	}
2822 
2823 	if (mddev->bitmap == NULL &&
2824 	    mddev->recovery_cp == MaxSector &&
2825 	    !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery) &&
2826 	    conf->fullsync == 0) {
2827 		*skipped = 1;
2828 		return max_sector - sector_nr;
2829 	}
2830 	/* before building a request, check if we can skip these blocks..
2831 	 * This call the bitmap_start_sync doesn't actually record anything
2832 	 */
2833 	if (!mddev->bitmap_ops->start_sync(mddev, sector_nr, &sync_blocks, true) &&
2834 	    !conf->fullsync && !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery)) {
2835 		/* We can skip this block, and probably several more */
2836 		*skipped = 1;
2837 		return sync_blocks;
2838 	}
2839 
2840 	/*
2841 	 * If there is non-resync activity waiting for a turn, then let it
2842 	 * though before starting on this new sync request.
2843 	 */
2844 	if (atomic_read(&conf->nr_waiting[idx]))
2845 		schedule_timeout_uninterruptible(1);
2846 
2847 	/* we are incrementing sector_nr below. To be safe, we check against
2848 	 * sector_nr + two times RESYNC_SECTORS
2849 	 */
2850 
2851 	mddev->bitmap_ops->cond_end_sync(mddev, sector_nr,
2852 		mddev_is_clustered(mddev) &&
2853 		(sector_nr + 2 * RESYNC_SECTORS > conf->cluster_sync_high));
2854 
2855 	if (raise_barrier(conf, sector_nr))
2856 		return 0;
2857 
2858 	r1_bio = raid1_alloc_init_r1buf(conf);
2859 
2860 	/*
2861 	 * If we get a correctably read error during resync or recovery,
2862 	 * we might want to read from a different device.  So we
2863 	 * flag all drives that could conceivably be read from for READ,
2864 	 * and any others (which will be non-In_sync devices) for WRITE.
2865 	 * If a read fails, we try reading from something else for which READ
2866 	 * is OK.
2867 	 */
2868 
2869 	r1_bio->mddev = mddev;
2870 	r1_bio->sector = sector_nr;
2871 	r1_bio->state = 0;
2872 	set_bit(R1BIO_IsSync, &r1_bio->state);
2873 	/* make sure good_sectors won't go across barrier unit boundary */
2874 	good_sectors = align_to_barrier_unit_end(sector_nr, good_sectors);
2875 
2876 	for (i = 0; i < conf->raid_disks * 2; i++) {
2877 		struct md_rdev *rdev;
2878 		bio = r1_bio->bios[i];
2879 
2880 		rdev = conf->mirrors[i].rdev;
2881 		if (rdev == NULL ||
2882 		    test_bit(Faulty, &rdev->flags)) {
2883 			if (i < conf->raid_disks)
2884 				still_degraded = true;
2885 		} else if (!test_bit(In_sync, &rdev->flags)) {
2886 			bio->bi_opf = REQ_OP_WRITE;
2887 			bio->bi_end_io = end_sync_write;
2888 			write_targets ++;
2889 		} else {
2890 			/* may need to read from here */
2891 			sector_t first_bad = MaxSector;
2892 			sector_t bad_sectors;
2893 
2894 			if (is_badblock(rdev, sector_nr, good_sectors,
2895 					&first_bad, &bad_sectors)) {
2896 				if (first_bad > sector_nr)
2897 					good_sectors = first_bad - sector_nr;
2898 				else {
2899 					bad_sectors -= (sector_nr - first_bad);
2900 					if (min_bad == 0 ||
2901 					    min_bad > bad_sectors)
2902 						min_bad = bad_sectors;
2903 				}
2904 			}
2905 			if (sector_nr < first_bad) {
2906 				if (test_bit(WriteMostly, &rdev->flags)) {
2907 					if (wonly < 0)
2908 						wonly = i;
2909 				} else {
2910 					if (disk < 0)
2911 						disk = i;
2912 				}
2913 				bio->bi_opf = REQ_OP_READ;
2914 				bio->bi_end_io = end_sync_read;
2915 				read_targets++;
2916 			} else if (!test_bit(WriteErrorSeen, &rdev->flags) &&
2917 				test_bit(MD_RECOVERY_SYNC, &mddev->recovery) &&
2918 				!test_bit(MD_RECOVERY_CHECK, &mddev->recovery)) {
2919 				/*
2920 				 * The device is suitable for reading (InSync),
2921 				 * but has bad block(s) here. Let's try to correct them,
2922 				 * if we are doing resync or repair. Otherwise, leave
2923 				 * this device alone for this sync request.
2924 				 */
2925 				bio->bi_opf = REQ_OP_WRITE;
2926 				bio->bi_end_io = end_sync_write;
2927 				write_targets++;
2928 			}
2929 		}
2930 		if (rdev && bio->bi_end_io) {
2931 			atomic_inc(&rdev->nr_pending);
2932 			bio->bi_iter.bi_sector = sector_nr + rdev->data_offset;
2933 			bio_set_dev(bio, rdev->bdev);
2934 			if (test_bit(FailFast, &rdev->flags))
2935 				bio->bi_opf |= MD_FAILFAST;
2936 		}
2937 	}
2938 	if (disk < 0)
2939 		disk = wonly;
2940 	r1_bio->read_disk = disk;
2941 
2942 	if (read_targets == 0 && min_bad > 0) {
2943 		/* These sectors are bad on all InSync devices, so we
2944 		 * need to mark them bad on all write targets
2945 		 */
2946 		int ok = 1;
2947 		for (i = 0 ; i < conf->raid_disks * 2 ; i++)
2948 			if (r1_bio->bios[i]->bi_end_io == end_sync_write) {
2949 				struct md_rdev *rdev = conf->mirrors[i].rdev;
2950 				ok = rdev_set_badblocks(rdev, sector_nr,
2951 							min_bad, 0
2952 					) && ok;
2953 			}
2954 		set_bit(MD_SB_CHANGE_DEVS, &mddev->sb_flags);
2955 		*skipped = 1;
2956 		put_buf(r1_bio);
2957 
2958 		if (!ok) {
2959 			/* Cannot record the badblocks, so need to
2960 			 * abort the resync.
2961 			 * If there are multiple read targets, could just
2962 			 * fail the really bad ones ???
2963 			 */
2964 			conf->recovery_disabled = mddev->recovery_disabled;
2965 			set_bit(MD_RECOVERY_INTR, &mddev->recovery);
2966 			return 0;
2967 		} else
2968 			return min_bad;
2969 
2970 	}
2971 	if (min_bad > 0 && min_bad < good_sectors) {
2972 		/* only resync enough to reach the next bad->good
2973 		 * transition */
2974 		good_sectors = min_bad;
2975 	}
2976 
2977 	if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery) && read_targets > 0)
2978 		/* extra read targets are also write targets */
2979 		write_targets += read_targets-1;
2980 
2981 	if (write_targets == 0 || read_targets == 0) {
2982 		/* There is nowhere to write, so all non-sync
2983 		 * drives must be failed - so we are finished
2984 		 */
2985 		sector_t rv;
2986 		if (min_bad > 0)
2987 			max_sector = sector_nr + min_bad;
2988 		rv = max_sector - sector_nr;
2989 		*skipped = 1;
2990 		put_buf(r1_bio);
2991 		return rv;
2992 	}
2993 
2994 	if (max_sector > mddev->resync_max)
2995 		max_sector = mddev->resync_max; /* Don't do IO beyond here */
2996 	if (max_sector > sector_nr + good_sectors)
2997 		max_sector = sector_nr + good_sectors;
2998 	nr_sectors = 0;
2999 	sync_blocks = 0;
3000 	do {
3001 		struct page *page;
3002 		int len = PAGE_SIZE;
3003 		if (sector_nr + (len>>9) > max_sector)
3004 			len = (max_sector - sector_nr) << 9;
3005 		if (len == 0)
3006 			break;
3007 		if (sync_blocks == 0) {
3008 			if (!mddev->bitmap_ops->start_sync(mddev, sector_nr,
3009 						&sync_blocks, still_degraded) &&
3010 			    !conf->fullsync &&
3011 			    !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery))
3012 				break;
3013 			if ((len >> 9) > sync_blocks)
3014 				len = sync_blocks<<9;
3015 		}
3016 
3017 		for (i = 0 ; i < conf->raid_disks * 2; i++) {
3018 			struct resync_pages *rp;
3019 
3020 			bio = r1_bio->bios[i];
3021 			rp = get_resync_pages(bio);
3022 			if (bio->bi_end_io) {
3023 				page = resync_fetch_page(rp, page_idx);
3024 
3025 				/*
3026 				 * won't fail because the vec table is big
3027 				 * enough to hold all these pages
3028 				 */
3029 				__bio_add_page(bio, page, len, 0);
3030 			}
3031 		}
3032 		nr_sectors += len>>9;
3033 		sector_nr += len>>9;
3034 		sync_blocks -= (len>>9);
3035 	} while (++page_idx < RESYNC_PAGES);
3036 
3037 	r1_bio->sectors = nr_sectors;
3038 
3039 	if (mddev_is_clustered(mddev) &&
3040 			conf->cluster_sync_high < sector_nr + nr_sectors) {
3041 		conf->cluster_sync_low = mddev->curr_resync_completed;
3042 		conf->cluster_sync_high = conf->cluster_sync_low + CLUSTER_RESYNC_WINDOW_SECTORS;
3043 		/* Send resync message */
3044 		mddev->cluster_ops->resync_info_update(mddev,
3045 						       conf->cluster_sync_low,
3046 						       conf->cluster_sync_high);
3047 	}
3048 
3049 	/* For a user-requested sync, we read all readable devices and do a
3050 	 * compare
3051 	 */
3052 	if (test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery)) {
3053 		atomic_set(&r1_bio->remaining, read_targets);
3054 		for (i = 0; i < conf->raid_disks * 2 && read_targets; i++) {
3055 			bio = r1_bio->bios[i];
3056 			if (bio->bi_end_io == end_sync_read) {
3057 				read_targets--;
3058 				if (read_targets == 1)
3059 					bio->bi_opf &= ~MD_FAILFAST;
3060 				submit_bio_noacct(bio);
3061 			}
3062 		}
3063 	} else {
3064 		atomic_set(&r1_bio->remaining, 1);
3065 		bio = r1_bio->bios[r1_bio->read_disk];
3066 		if (read_targets == 1)
3067 			bio->bi_opf &= ~MD_FAILFAST;
3068 		submit_bio_noacct(bio);
3069 	}
3070 	return nr_sectors;
3071 }
3072 
raid1_size(struct mddev * mddev,sector_t sectors,int raid_disks)3073 static sector_t raid1_size(struct mddev *mddev, sector_t sectors, int raid_disks)
3074 {
3075 	if (sectors)
3076 		return sectors;
3077 
3078 	return mddev->dev_sectors;
3079 }
3080 
setup_conf(struct mddev * mddev)3081 static struct r1conf *setup_conf(struct mddev *mddev)
3082 {
3083 	struct r1conf *conf;
3084 	int i;
3085 	struct raid1_info *disk;
3086 	struct md_rdev *rdev;
3087 	int err = -ENOMEM;
3088 
3089 	conf = kzalloc(sizeof(struct r1conf), GFP_KERNEL);
3090 	if (!conf)
3091 		goto abort;
3092 
3093 	conf->nr_pending = kcalloc(BARRIER_BUCKETS_NR,
3094 				   sizeof(atomic_t), GFP_KERNEL);
3095 	if (!conf->nr_pending)
3096 		goto abort;
3097 
3098 	conf->nr_waiting = kcalloc(BARRIER_BUCKETS_NR,
3099 				   sizeof(atomic_t), GFP_KERNEL);
3100 	if (!conf->nr_waiting)
3101 		goto abort;
3102 
3103 	conf->nr_queued = kcalloc(BARRIER_BUCKETS_NR,
3104 				  sizeof(atomic_t), GFP_KERNEL);
3105 	if (!conf->nr_queued)
3106 		goto abort;
3107 
3108 	conf->barrier = kcalloc(BARRIER_BUCKETS_NR,
3109 				sizeof(atomic_t), GFP_KERNEL);
3110 	if (!conf->barrier)
3111 		goto abort;
3112 
3113 	conf->mirrors = kzalloc(array3_size(sizeof(struct raid1_info),
3114 					    mddev->raid_disks, 2),
3115 				GFP_KERNEL);
3116 	if (!conf->mirrors)
3117 		goto abort;
3118 
3119 	conf->tmppage = alloc_page(GFP_KERNEL);
3120 	if (!conf->tmppage)
3121 		goto abort;
3122 
3123 	conf->poolinfo = kzalloc(sizeof(*conf->poolinfo), GFP_KERNEL);
3124 	if (!conf->poolinfo)
3125 		goto abort;
3126 	conf->poolinfo->raid_disks = mddev->raid_disks * 2;
3127 	err = mempool_init(&conf->r1bio_pool, NR_RAID_BIOS, r1bio_pool_alloc,
3128 			   rbio_pool_free, conf->poolinfo);
3129 	if (err)
3130 		goto abort;
3131 
3132 	err = bioset_init(&conf->bio_split, BIO_POOL_SIZE, 0, 0);
3133 	if (err)
3134 		goto abort;
3135 
3136 	conf->poolinfo->mddev = mddev;
3137 
3138 	err = -EINVAL;
3139 	spin_lock_init(&conf->device_lock);
3140 	conf->raid_disks = mddev->raid_disks;
3141 	rdev_for_each(rdev, mddev) {
3142 		int disk_idx = rdev->raid_disk;
3143 
3144 		if (disk_idx >= conf->raid_disks || disk_idx < 0)
3145 			continue;
3146 
3147 		if (!raid1_add_conf(conf, rdev, disk_idx,
3148 				    test_bit(Replacement, &rdev->flags)))
3149 			goto abort;
3150 	}
3151 	conf->mddev = mddev;
3152 	INIT_LIST_HEAD(&conf->retry_list);
3153 	INIT_LIST_HEAD(&conf->bio_end_io_list);
3154 
3155 	spin_lock_init(&conf->resync_lock);
3156 	init_waitqueue_head(&conf->wait_barrier);
3157 
3158 	bio_list_init(&conf->pending_bio_list);
3159 	conf->recovery_disabled = mddev->recovery_disabled - 1;
3160 
3161 	err = -EIO;
3162 	for (i = 0; i < conf->raid_disks * 2; i++) {
3163 
3164 		disk = conf->mirrors + i;
3165 
3166 		if (i < conf->raid_disks &&
3167 		    disk[conf->raid_disks].rdev) {
3168 			/* This slot has a replacement. */
3169 			if (!disk->rdev) {
3170 				/* No original, just make the replacement
3171 				 * a recovering spare
3172 				 */
3173 				disk->rdev =
3174 					disk[conf->raid_disks].rdev;
3175 				disk[conf->raid_disks].rdev = NULL;
3176 			} else if (!test_bit(In_sync, &disk->rdev->flags))
3177 				/* Original is not in_sync - bad */
3178 				goto abort;
3179 		}
3180 
3181 		if (!disk->rdev ||
3182 		    !test_bit(In_sync, &disk->rdev->flags)) {
3183 			disk->head_position = 0;
3184 			if (disk->rdev &&
3185 			    (disk->rdev->saved_raid_disk < 0))
3186 				conf->fullsync = 1;
3187 		}
3188 	}
3189 
3190 	err = -ENOMEM;
3191 	rcu_assign_pointer(conf->thread,
3192 			   md_register_thread(raid1d, mddev, "raid1"));
3193 	if (!conf->thread)
3194 		goto abort;
3195 
3196 	return conf;
3197 
3198  abort:
3199 	if (conf) {
3200 		mempool_exit(&conf->r1bio_pool);
3201 		kfree(conf->mirrors);
3202 		safe_put_page(conf->tmppage);
3203 		kfree(conf->poolinfo);
3204 		kfree(conf->nr_pending);
3205 		kfree(conf->nr_waiting);
3206 		kfree(conf->nr_queued);
3207 		kfree(conf->barrier);
3208 		bioset_exit(&conf->bio_split);
3209 		kfree(conf);
3210 	}
3211 	return ERR_PTR(err);
3212 }
3213 
raid1_set_limits(struct mddev * mddev)3214 static int raid1_set_limits(struct mddev *mddev)
3215 {
3216 	struct queue_limits lim;
3217 	int err;
3218 
3219 	md_init_stacking_limits(&lim);
3220 	lim.max_write_zeroes_sectors = 0;
3221 	lim.features |= BLK_FEAT_ATOMIC_WRITES;
3222 	err = mddev_stack_rdev_limits(mddev, &lim, MDDEV_STACK_INTEGRITY);
3223 	if (err)
3224 		return err;
3225 	return queue_limits_set(mddev->gendisk->queue, &lim);
3226 }
3227 
raid1_run(struct mddev * mddev)3228 static int raid1_run(struct mddev *mddev)
3229 {
3230 	struct r1conf *conf;
3231 	int i;
3232 	int ret;
3233 
3234 	if (mddev->level != 1) {
3235 		pr_warn("md/raid1:%s: raid level not set to mirroring (%d)\n",
3236 			mdname(mddev), mddev->level);
3237 		return -EIO;
3238 	}
3239 	if (mddev->reshape_position != MaxSector) {
3240 		pr_warn("md/raid1:%s: reshape_position set but not supported\n",
3241 			mdname(mddev));
3242 		return -EIO;
3243 	}
3244 
3245 	/*
3246 	 * copy the already verified devices into our private RAID1
3247 	 * bookkeeping area. [whatever we allocate in run(),
3248 	 * should be freed in raid1_free()]
3249 	 */
3250 	if (mddev->private == NULL)
3251 		conf = setup_conf(mddev);
3252 	else
3253 		conf = mddev->private;
3254 
3255 	if (IS_ERR(conf))
3256 		return PTR_ERR(conf);
3257 
3258 	if (!mddev_is_dm(mddev)) {
3259 		ret = raid1_set_limits(mddev);
3260 		if (ret) {
3261 			if (!mddev->private)
3262 				raid1_free(mddev, conf);
3263 			return ret;
3264 		}
3265 	}
3266 
3267 	mddev->degraded = 0;
3268 	for (i = 0; i < conf->raid_disks; i++)
3269 		if (conf->mirrors[i].rdev == NULL ||
3270 		    !test_bit(In_sync, &conf->mirrors[i].rdev->flags) ||
3271 		    test_bit(Faulty, &conf->mirrors[i].rdev->flags))
3272 			mddev->degraded++;
3273 	/*
3274 	 * RAID1 needs at least one disk in active
3275 	 */
3276 	if (conf->raid_disks - mddev->degraded < 1) {
3277 		md_unregister_thread(mddev, &conf->thread);
3278 		if (!mddev->private)
3279 			raid1_free(mddev, conf);
3280 		return -EINVAL;
3281 	}
3282 
3283 	if (conf->raid_disks - mddev->degraded == 1)
3284 		mddev->recovery_cp = MaxSector;
3285 
3286 	if (mddev->recovery_cp != MaxSector)
3287 		pr_info("md/raid1:%s: not clean -- starting background reconstruction\n",
3288 			mdname(mddev));
3289 	pr_info("md/raid1:%s: active with %d out of %d mirrors\n",
3290 		mdname(mddev), mddev->raid_disks - mddev->degraded,
3291 		mddev->raid_disks);
3292 
3293 	/*
3294 	 * Ok, everything is just fine now
3295 	 */
3296 	rcu_assign_pointer(mddev->thread, conf->thread);
3297 	rcu_assign_pointer(conf->thread, NULL);
3298 	mddev->private = conf;
3299 	set_bit(MD_FAILFAST_SUPPORTED, &mddev->flags);
3300 
3301 	md_set_array_sectors(mddev, raid1_size(mddev, 0, 0));
3302 
3303 	ret = md_integrity_register(mddev);
3304 	if (ret)
3305 		md_unregister_thread(mddev, &mddev->thread);
3306 	return ret;
3307 }
3308 
raid1_free(struct mddev * mddev,void * priv)3309 static void raid1_free(struct mddev *mddev, void *priv)
3310 {
3311 	struct r1conf *conf = priv;
3312 
3313 	mempool_exit(&conf->r1bio_pool);
3314 	kfree(conf->mirrors);
3315 	safe_put_page(conf->tmppage);
3316 	kfree(conf->poolinfo);
3317 	kfree(conf->nr_pending);
3318 	kfree(conf->nr_waiting);
3319 	kfree(conf->nr_queued);
3320 	kfree(conf->barrier);
3321 	bioset_exit(&conf->bio_split);
3322 	kfree(conf);
3323 }
3324 
raid1_resize(struct mddev * mddev,sector_t sectors)3325 static int raid1_resize(struct mddev *mddev, sector_t sectors)
3326 {
3327 	/* no resync is happening, and there is enough space
3328 	 * on all devices, so we can resize.
3329 	 * We need to make sure resync covers any new space.
3330 	 * If the array is shrinking we should possibly wait until
3331 	 * any io in the removed space completes, but it hardly seems
3332 	 * worth it.
3333 	 */
3334 	sector_t newsize = raid1_size(mddev, sectors, 0);
3335 	int ret;
3336 
3337 	if (mddev->external_size &&
3338 	    mddev->array_sectors > newsize)
3339 		return -EINVAL;
3340 
3341 	ret = mddev->bitmap_ops->resize(mddev, newsize, 0, false);
3342 	if (ret)
3343 		return ret;
3344 
3345 	md_set_array_sectors(mddev, newsize);
3346 	if (sectors > mddev->dev_sectors &&
3347 	    mddev->recovery_cp > mddev->dev_sectors) {
3348 		mddev->recovery_cp = mddev->dev_sectors;
3349 		set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
3350 	}
3351 	mddev->dev_sectors = sectors;
3352 	mddev->resync_max_sectors = sectors;
3353 	return 0;
3354 }
3355 
raid1_reshape(struct mddev * mddev)3356 static int raid1_reshape(struct mddev *mddev)
3357 {
3358 	/* We need to:
3359 	 * 1/ resize the r1bio_pool
3360 	 * 2/ resize conf->mirrors
3361 	 *
3362 	 * We allocate a new r1bio_pool if we can.
3363 	 * Then raise a device barrier and wait until all IO stops.
3364 	 * Then resize conf->mirrors and swap in the new r1bio pool.
3365 	 *
3366 	 * At the same time, we "pack" the devices so that all the missing
3367 	 * devices have the higher raid_disk numbers.
3368 	 */
3369 	mempool_t newpool, oldpool;
3370 	struct pool_info *newpoolinfo;
3371 	struct raid1_info *newmirrors;
3372 	struct r1conf *conf = mddev->private;
3373 	int cnt, raid_disks;
3374 	unsigned long flags;
3375 	int d, d2;
3376 	int ret;
3377 
3378 	memset(&newpool, 0, sizeof(newpool));
3379 	memset(&oldpool, 0, sizeof(oldpool));
3380 
3381 	/* Cannot change chunk_size, layout, or level */
3382 	if (mddev->chunk_sectors != mddev->new_chunk_sectors ||
3383 	    mddev->layout != mddev->new_layout ||
3384 	    mddev->level != mddev->new_level) {
3385 		mddev->new_chunk_sectors = mddev->chunk_sectors;
3386 		mddev->new_layout = mddev->layout;
3387 		mddev->new_level = mddev->level;
3388 		return -EINVAL;
3389 	}
3390 
3391 	if (!mddev_is_clustered(mddev))
3392 		md_allow_write(mddev);
3393 
3394 	raid_disks = mddev->raid_disks + mddev->delta_disks;
3395 
3396 	if (raid_disks < conf->raid_disks) {
3397 		cnt=0;
3398 		for (d= 0; d < conf->raid_disks; d++)
3399 			if (conf->mirrors[d].rdev)
3400 				cnt++;
3401 		if (cnt > raid_disks)
3402 			return -EBUSY;
3403 	}
3404 
3405 	newpoolinfo = kmalloc(sizeof(*newpoolinfo), GFP_KERNEL);
3406 	if (!newpoolinfo)
3407 		return -ENOMEM;
3408 	newpoolinfo->mddev = mddev;
3409 	newpoolinfo->raid_disks = raid_disks * 2;
3410 
3411 	ret = mempool_init(&newpool, NR_RAID_BIOS, r1bio_pool_alloc,
3412 			   rbio_pool_free, newpoolinfo);
3413 	if (ret) {
3414 		kfree(newpoolinfo);
3415 		return ret;
3416 	}
3417 	newmirrors = kzalloc(array3_size(sizeof(struct raid1_info),
3418 					 raid_disks, 2),
3419 			     GFP_KERNEL);
3420 	if (!newmirrors) {
3421 		kfree(newpoolinfo);
3422 		mempool_exit(&newpool);
3423 		return -ENOMEM;
3424 	}
3425 
3426 	freeze_array(conf, 0);
3427 
3428 	/* ok, everything is stopped */
3429 	oldpool = conf->r1bio_pool;
3430 	conf->r1bio_pool = newpool;
3431 
3432 	for (d = d2 = 0; d < conf->raid_disks; d++) {
3433 		struct md_rdev *rdev = conf->mirrors[d].rdev;
3434 		if (rdev && rdev->raid_disk != d2) {
3435 			sysfs_unlink_rdev(mddev, rdev);
3436 			rdev->raid_disk = d2;
3437 			sysfs_unlink_rdev(mddev, rdev);
3438 			if (sysfs_link_rdev(mddev, rdev))
3439 				pr_warn("md/raid1:%s: cannot register rd%d\n",
3440 					mdname(mddev), rdev->raid_disk);
3441 		}
3442 		if (rdev)
3443 			newmirrors[d2++].rdev = rdev;
3444 	}
3445 	kfree(conf->mirrors);
3446 	conf->mirrors = newmirrors;
3447 	kfree(conf->poolinfo);
3448 	conf->poolinfo = newpoolinfo;
3449 
3450 	spin_lock_irqsave(&conf->device_lock, flags);
3451 	mddev->degraded += (raid_disks - conf->raid_disks);
3452 	spin_unlock_irqrestore(&conf->device_lock, flags);
3453 	conf->raid_disks = mddev->raid_disks = raid_disks;
3454 	mddev->delta_disks = 0;
3455 
3456 	unfreeze_array(conf);
3457 
3458 	set_bit(MD_RECOVERY_RECOVER, &mddev->recovery);
3459 	set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
3460 	md_wakeup_thread(mddev->thread);
3461 
3462 	mempool_exit(&oldpool);
3463 	return 0;
3464 }
3465 
raid1_quiesce(struct mddev * mddev,int quiesce)3466 static void raid1_quiesce(struct mddev *mddev, int quiesce)
3467 {
3468 	struct r1conf *conf = mddev->private;
3469 
3470 	if (quiesce)
3471 		freeze_array(conf, 0);
3472 	else
3473 		unfreeze_array(conf);
3474 }
3475 
raid1_takeover(struct mddev * mddev)3476 static void *raid1_takeover(struct mddev *mddev)
3477 {
3478 	/* raid1 can take over:
3479 	 *  raid5 with 2 devices, any layout or chunk size
3480 	 */
3481 	if (mddev->level == 5 && mddev->raid_disks == 2) {
3482 		struct r1conf *conf;
3483 		mddev->new_level = 1;
3484 		mddev->new_layout = 0;
3485 		mddev->new_chunk_sectors = 0;
3486 		conf = setup_conf(mddev);
3487 		if (!IS_ERR(conf)) {
3488 			/* Array must appear to be quiesced */
3489 			conf->array_frozen = 1;
3490 			mddev_clear_unsupported_flags(mddev,
3491 				UNSUPPORTED_MDDEV_FLAGS);
3492 		}
3493 		return conf;
3494 	}
3495 	return ERR_PTR(-EINVAL);
3496 }
3497 
3498 static struct md_personality raid1_personality =
3499 {
3500 	.head = {
3501 		.type	= MD_PERSONALITY,
3502 		.id	= ID_RAID1,
3503 		.name	= "raid1",
3504 		.owner	= THIS_MODULE,
3505 	},
3506 
3507 	.make_request	= raid1_make_request,
3508 	.run		= raid1_run,
3509 	.free		= raid1_free,
3510 	.status		= raid1_status,
3511 	.error_handler	= raid1_error,
3512 	.hot_add_disk	= raid1_add_disk,
3513 	.hot_remove_disk= raid1_remove_disk,
3514 	.spare_active	= raid1_spare_active,
3515 	.sync_request	= raid1_sync_request,
3516 	.resize		= raid1_resize,
3517 	.size		= raid1_size,
3518 	.check_reshape	= raid1_reshape,
3519 	.quiesce	= raid1_quiesce,
3520 	.takeover	= raid1_takeover,
3521 };
3522 
raid1_init(void)3523 static int __init raid1_init(void)
3524 {
3525 	return register_md_submodule(&raid1_personality.head);
3526 }
3527 
raid1_exit(void)3528 static void __exit raid1_exit(void)
3529 {
3530 	unregister_md_submodule(&raid1_personality.head);
3531 }
3532 
3533 module_init(raid1_init);
3534 module_exit(raid1_exit);
3535 MODULE_LICENSE("GPL");
3536 MODULE_DESCRIPTION("RAID1 (mirroring) personality for MD");
3537 MODULE_ALIAS("md-personality-3"); /* RAID1 */
3538 MODULE_ALIAS("md-raid1");
3539 MODULE_ALIAS("md-level-1");
3540