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1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * raid10.c : Multiple Devices driver for Linux
4  *
5  * Copyright (C) 2000-2004 Neil Brown
6  *
7  * RAID-10 support for md.
8  *
9  * Base on code in raid1.c.  See raid1.c for further copyright information.
10  */
11 
12 #include <linux/slab.h>
13 #include <linux/delay.h>
14 #include <linux/blkdev.h>
15 #include <linux/module.h>
16 #include <linux/seq_file.h>
17 #include <linux/ratelimit.h>
18 #include <linux/kthread.h>
19 #include <linux/raid/md_p.h>
20 #include <trace/events/block.h>
21 #include "md.h"
22 #include "raid10.h"
23 #include "raid0.h"
24 #include "md-bitmap.h"
25 
26 /*
27  * RAID10 provides a combination of RAID0 and RAID1 functionality.
28  * The layout of data is defined by
29  *    chunk_size
30  *    raid_disks
31  *    near_copies (stored in low byte of layout)
32  *    far_copies (stored in second byte of layout)
33  *    far_offset (stored in bit 16 of layout )
34  *    use_far_sets (stored in bit 17 of layout )
35  *    use_far_sets_bugfixed (stored in bit 18 of layout )
36  *
37  * The data to be stored is divided into chunks using chunksize.  Each device
38  * is divided into far_copies sections.   In each section, chunks are laid out
39  * in a style similar to raid0, but near_copies copies of each chunk is stored
40  * (each on a different drive).  The starting device for each section is offset
41  * near_copies from the starting device of the previous section.  Thus there
42  * are (near_copies * far_copies) of each chunk, and each is on a different
43  * drive.  near_copies and far_copies must be at least one, and their product
44  * is at most raid_disks.
45  *
46  * If far_offset is true, then the far_copies are handled a bit differently.
47  * The copies are still in different stripes, but instead of being very far
48  * apart on disk, there are adjacent stripes.
49  *
50  * The far and offset algorithms are handled slightly differently if
51  * 'use_far_sets' is true.  In this case, the array's devices are grouped into
52  * sets that are (near_copies * far_copies) in size.  The far copied stripes
53  * are still shifted by 'near_copies' devices, but this shifting stays confined
54  * to the set rather than the entire array.  This is done to improve the number
55  * of device combinations that can fail without causing the array to fail.
56  * Example 'far' algorithm w/o 'use_far_sets' (each letter represents a chunk
57  * on a device):
58  *    A B C D    A B C D E
59  *      ...         ...
60  *    D A B C    E A B C D
61  * Example 'far' algorithm w/ 'use_far_sets' enabled (sets illustrated w/ []'s):
62  *    [A B] [C D]    [A B] [C D E]
63  *    |...| |...|    |...| | ... |
64  *    [B A] [D C]    [B A] [E C D]
65  */
66 
67 static void allow_barrier(struct r10conf *conf);
68 static void lower_barrier(struct r10conf *conf);
69 static int _enough(struct r10conf *conf, int previous, int ignore);
70 static int enough(struct r10conf *conf, int ignore);
71 static sector_t reshape_request(struct mddev *mddev, sector_t sector_nr,
72 				int *skipped);
73 static void reshape_request_write(struct mddev *mddev, struct r10bio *r10_bio);
74 static void end_reshape_write(struct bio *bio);
75 static void end_reshape(struct r10conf *conf);
76 
77 #define raid10_log(md, fmt, args...)				\
78 	do { if ((md)->queue) blk_add_trace_msg((md)->queue, "raid10 " fmt, ##args); } while (0)
79 
80 #include "raid1-10.c"
81 
82 /*
83  * for resync bio, r10bio pointer can be retrieved from the per-bio
84  * 'struct resync_pages'.
85  */
get_resync_r10bio(struct bio * bio)86 static inline struct r10bio *get_resync_r10bio(struct bio *bio)
87 {
88 	return get_resync_pages(bio)->raid_bio;
89 }
90 
r10bio_pool_alloc(gfp_t gfp_flags,void * data)91 static void * r10bio_pool_alloc(gfp_t gfp_flags, void *data)
92 {
93 	struct r10conf *conf = data;
94 	int size = offsetof(struct r10bio, devs[conf->copies]);
95 
96 	/* allocate a r10bio with room for raid_disks entries in the
97 	 * bios array */
98 	return kzalloc(size, gfp_flags);
99 }
100 
101 #define RESYNC_SECTORS (RESYNC_BLOCK_SIZE >> 9)
102 /* amount of memory to reserve for resync requests */
103 #define RESYNC_WINDOW (1024*1024)
104 /* maximum number of concurrent requests, memory permitting */
105 #define RESYNC_DEPTH (32*1024*1024/RESYNC_BLOCK_SIZE)
106 #define CLUSTER_RESYNC_WINDOW (32 * RESYNC_WINDOW)
107 #define CLUSTER_RESYNC_WINDOW_SECTORS (CLUSTER_RESYNC_WINDOW >> 9)
108 
109 /*
110  * When performing a resync, we need to read and compare, so
111  * we need as many pages are there are copies.
112  * When performing a recovery, we need 2 bios, one for read,
113  * one for write (we recover only one drive per r10buf)
114  *
115  */
r10buf_pool_alloc(gfp_t gfp_flags,void * data)116 static void * r10buf_pool_alloc(gfp_t gfp_flags, void *data)
117 {
118 	struct r10conf *conf = data;
119 	struct r10bio *r10_bio;
120 	struct bio *bio;
121 	int j;
122 	int nalloc, nalloc_rp;
123 	struct resync_pages *rps;
124 
125 	r10_bio = r10bio_pool_alloc(gfp_flags, conf);
126 	if (!r10_bio)
127 		return NULL;
128 
129 	if (test_bit(MD_RECOVERY_SYNC, &conf->mddev->recovery) ||
130 	    test_bit(MD_RECOVERY_RESHAPE, &conf->mddev->recovery))
131 		nalloc = conf->copies; /* resync */
132 	else
133 		nalloc = 2; /* recovery */
134 
135 	/* allocate once for all bios */
136 	if (!conf->have_replacement)
137 		nalloc_rp = nalloc;
138 	else
139 		nalloc_rp = nalloc * 2;
140 	rps = kmalloc_array(nalloc_rp, sizeof(struct resync_pages), gfp_flags);
141 	if (!rps)
142 		goto out_free_r10bio;
143 
144 	/*
145 	 * Allocate bios.
146 	 */
147 	for (j = nalloc ; j-- ; ) {
148 		bio = bio_kmalloc(gfp_flags, RESYNC_PAGES);
149 		if (!bio)
150 			goto out_free_bio;
151 		r10_bio->devs[j].bio = bio;
152 		if (!conf->have_replacement)
153 			continue;
154 		bio = bio_kmalloc(gfp_flags, RESYNC_PAGES);
155 		if (!bio)
156 			goto out_free_bio;
157 		r10_bio->devs[j].repl_bio = bio;
158 	}
159 	/*
160 	 * Allocate RESYNC_PAGES data pages and attach them
161 	 * where needed.
162 	 */
163 	for (j = 0; j < nalloc; j++) {
164 		struct bio *rbio = r10_bio->devs[j].repl_bio;
165 		struct resync_pages *rp, *rp_repl;
166 
167 		rp = &rps[j];
168 		if (rbio)
169 			rp_repl = &rps[nalloc + j];
170 
171 		bio = r10_bio->devs[j].bio;
172 
173 		if (!j || test_bit(MD_RECOVERY_SYNC,
174 				   &conf->mddev->recovery)) {
175 			if (resync_alloc_pages(rp, gfp_flags))
176 				goto out_free_pages;
177 		} else {
178 			memcpy(rp, &rps[0], sizeof(*rp));
179 			resync_get_all_pages(rp);
180 		}
181 
182 		rp->raid_bio = r10_bio;
183 		bio->bi_private = rp;
184 		if (rbio) {
185 			memcpy(rp_repl, rp, sizeof(*rp));
186 			rbio->bi_private = rp_repl;
187 		}
188 	}
189 
190 	return r10_bio;
191 
192 out_free_pages:
193 	while (--j >= 0)
194 		resync_free_pages(&rps[j]);
195 
196 	j = 0;
197 out_free_bio:
198 	for ( ; j < nalloc; j++) {
199 		if (r10_bio->devs[j].bio)
200 			bio_put(r10_bio->devs[j].bio);
201 		if (r10_bio->devs[j].repl_bio)
202 			bio_put(r10_bio->devs[j].repl_bio);
203 	}
204 	kfree(rps);
205 out_free_r10bio:
206 	rbio_pool_free(r10_bio, conf);
207 	return NULL;
208 }
209 
r10buf_pool_free(void * __r10_bio,void * data)210 static void r10buf_pool_free(void *__r10_bio, void *data)
211 {
212 	struct r10conf *conf = data;
213 	struct r10bio *r10bio = __r10_bio;
214 	int j;
215 	struct resync_pages *rp = NULL;
216 
217 	for (j = conf->copies; j--; ) {
218 		struct bio *bio = r10bio->devs[j].bio;
219 
220 		if (bio) {
221 			rp = get_resync_pages(bio);
222 			resync_free_pages(rp);
223 			bio_put(bio);
224 		}
225 
226 		bio = r10bio->devs[j].repl_bio;
227 		if (bio)
228 			bio_put(bio);
229 	}
230 
231 	/* resync pages array stored in the 1st bio's .bi_private */
232 	kfree(rp);
233 
234 	rbio_pool_free(r10bio, conf);
235 }
236 
put_all_bios(struct r10conf * conf,struct r10bio * r10_bio)237 static void put_all_bios(struct r10conf *conf, struct r10bio *r10_bio)
238 {
239 	int i;
240 
241 	for (i = 0; i < conf->copies; i++) {
242 		struct bio **bio = & r10_bio->devs[i].bio;
243 		if (!BIO_SPECIAL(*bio))
244 			bio_put(*bio);
245 		*bio = NULL;
246 		bio = &r10_bio->devs[i].repl_bio;
247 		if (r10_bio->read_slot < 0 && !BIO_SPECIAL(*bio))
248 			bio_put(*bio);
249 		*bio = NULL;
250 	}
251 }
252 
free_r10bio(struct r10bio * r10_bio)253 static void free_r10bio(struct r10bio *r10_bio)
254 {
255 	struct r10conf *conf = r10_bio->mddev->private;
256 
257 	put_all_bios(conf, r10_bio);
258 	mempool_free(r10_bio, &conf->r10bio_pool);
259 }
260 
put_buf(struct r10bio * r10_bio)261 static void put_buf(struct r10bio *r10_bio)
262 {
263 	struct r10conf *conf = r10_bio->mddev->private;
264 
265 	mempool_free(r10_bio, &conf->r10buf_pool);
266 
267 	lower_barrier(conf);
268 }
269 
reschedule_retry(struct r10bio * r10_bio)270 static void reschedule_retry(struct r10bio *r10_bio)
271 {
272 	unsigned long flags;
273 	struct mddev *mddev = r10_bio->mddev;
274 	struct r10conf *conf = mddev->private;
275 
276 	spin_lock_irqsave(&conf->device_lock, flags);
277 	list_add(&r10_bio->retry_list, &conf->retry_list);
278 	conf->nr_queued ++;
279 	spin_unlock_irqrestore(&conf->device_lock, flags);
280 
281 	/* wake up frozen array... */
282 	wake_up(&conf->wait_barrier);
283 
284 	md_wakeup_thread(mddev->thread);
285 }
286 
287 /*
288  * raid_end_bio_io() is called when we have finished servicing a mirrored
289  * operation and are ready to return a success/failure code to the buffer
290  * cache layer.
291  */
raid_end_bio_io(struct r10bio * r10_bio)292 static void raid_end_bio_io(struct r10bio *r10_bio)
293 {
294 	struct bio *bio = r10_bio->master_bio;
295 	struct r10conf *conf = r10_bio->mddev->private;
296 
297 	if (!test_bit(R10BIO_Uptodate, &r10_bio->state))
298 		bio->bi_status = BLK_STS_IOERR;
299 
300 	bio_endio(bio);
301 	/*
302 	 * Wake up any possible resync thread that waits for the device
303 	 * to go idle.
304 	 */
305 	allow_barrier(conf);
306 
307 	free_r10bio(r10_bio);
308 }
309 
310 /*
311  * Update disk head position estimator based on IRQ completion info.
312  */
update_head_pos(int slot,struct r10bio * r10_bio)313 static inline void update_head_pos(int slot, struct r10bio *r10_bio)
314 {
315 	struct r10conf *conf = r10_bio->mddev->private;
316 
317 	conf->mirrors[r10_bio->devs[slot].devnum].head_position =
318 		r10_bio->devs[slot].addr + (r10_bio->sectors);
319 }
320 
321 /*
322  * Find the disk number which triggered given bio
323  */
find_bio_disk(struct r10conf * conf,struct r10bio * r10_bio,struct bio * bio,int * slotp,int * replp)324 static int find_bio_disk(struct r10conf *conf, struct r10bio *r10_bio,
325 			 struct bio *bio, int *slotp, int *replp)
326 {
327 	int slot;
328 	int repl = 0;
329 
330 	for (slot = 0; slot < conf->copies; slot++) {
331 		if (r10_bio->devs[slot].bio == bio)
332 			break;
333 		if (r10_bio->devs[slot].repl_bio == bio) {
334 			repl = 1;
335 			break;
336 		}
337 	}
338 
339 	BUG_ON(slot == conf->copies);
340 	update_head_pos(slot, r10_bio);
341 
342 	if (slotp)
343 		*slotp = slot;
344 	if (replp)
345 		*replp = repl;
346 	return r10_bio->devs[slot].devnum;
347 }
348 
raid10_end_read_request(struct bio * bio)349 static void raid10_end_read_request(struct bio *bio)
350 {
351 	int uptodate = !bio->bi_status;
352 	struct r10bio *r10_bio = bio->bi_private;
353 	int slot;
354 	struct md_rdev *rdev;
355 	struct r10conf *conf = r10_bio->mddev->private;
356 
357 	slot = r10_bio->read_slot;
358 	rdev = r10_bio->devs[slot].rdev;
359 	/*
360 	 * this branch is our 'one mirror IO has finished' event handler:
361 	 */
362 	update_head_pos(slot, r10_bio);
363 
364 	if (uptodate) {
365 		/*
366 		 * Set R10BIO_Uptodate in our master bio, so that
367 		 * we will return a good error code to the higher
368 		 * levels even if IO on some other mirrored buffer fails.
369 		 *
370 		 * The 'master' represents the composite IO operation to
371 		 * user-side. So if something waits for IO, then it will
372 		 * wait for the 'master' bio.
373 		 */
374 		set_bit(R10BIO_Uptodate, &r10_bio->state);
375 	} else {
376 		/* If all other devices that store this block have
377 		 * failed, we want to return the error upwards rather
378 		 * than fail the last device.  Here we redefine
379 		 * "uptodate" to mean "Don't want to retry"
380 		 */
381 		if (!_enough(conf, test_bit(R10BIO_Previous, &r10_bio->state),
382 			     rdev->raid_disk))
383 			uptodate = 1;
384 	}
385 	if (uptodate) {
386 		raid_end_bio_io(r10_bio);
387 		rdev_dec_pending(rdev, conf->mddev);
388 	} else {
389 		/*
390 		 * oops, read error - keep the refcount on the rdev
391 		 */
392 		char b[BDEVNAME_SIZE];
393 		pr_err_ratelimited("md/raid10:%s: %s: rescheduling sector %llu\n",
394 				   mdname(conf->mddev),
395 				   bdevname(rdev->bdev, b),
396 				   (unsigned long long)r10_bio->sector);
397 		set_bit(R10BIO_ReadError, &r10_bio->state);
398 		reschedule_retry(r10_bio);
399 	}
400 }
401 
close_write(struct r10bio * r10_bio)402 static void close_write(struct r10bio *r10_bio)
403 {
404 	/* clear the bitmap if all writes complete successfully */
405 	md_bitmap_endwrite(r10_bio->mddev->bitmap, r10_bio->sector,
406 			   r10_bio->sectors,
407 			   !test_bit(R10BIO_Degraded, &r10_bio->state),
408 			   0);
409 	md_write_end(r10_bio->mddev);
410 }
411 
one_write_done(struct r10bio * r10_bio)412 static void one_write_done(struct r10bio *r10_bio)
413 {
414 	if (atomic_dec_and_test(&r10_bio->remaining)) {
415 		if (test_bit(R10BIO_WriteError, &r10_bio->state))
416 			reschedule_retry(r10_bio);
417 		else {
418 			close_write(r10_bio);
419 			if (test_bit(R10BIO_MadeGood, &r10_bio->state))
420 				reschedule_retry(r10_bio);
421 			else
422 				raid_end_bio_io(r10_bio);
423 		}
424 	}
425 }
426 
raid10_end_write_request(struct bio * bio)427 static void raid10_end_write_request(struct bio *bio)
428 {
429 	struct r10bio *r10_bio = bio->bi_private;
430 	int dev;
431 	int dec_rdev = 1;
432 	struct r10conf *conf = r10_bio->mddev->private;
433 	int slot, repl;
434 	struct md_rdev *rdev = NULL;
435 	struct bio *to_put = NULL;
436 	bool discard_error;
437 
438 	discard_error = bio->bi_status && bio_op(bio) == REQ_OP_DISCARD;
439 
440 	dev = find_bio_disk(conf, r10_bio, bio, &slot, &repl);
441 
442 	if (repl)
443 		rdev = conf->mirrors[dev].replacement;
444 	if (!rdev) {
445 		smp_rmb();
446 		repl = 0;
447 		rdev = conf->mirrors[dev].rdev;
448 	}
449 	/*
450 	 * this branch is our 'one mirror IO has finished' event handler:
451 	 */
452 	if (bio->bi_status && !discard_error) {
453 		if (repl)
454 			/* Never record new bad blocks to replacement,
455 			 * just fail it.
456 			 */
457 			md_error(rdev->mddev, rdev);
458 		else {
459 			set_bit(WriteErrorSeen,	&rdev->flags);
460 			if (!test_and_set_bit(WantReplacement, &rdev->flags))
461 				set_bit(MD_RECOVERY_NEEDED,
462 					&rdev->mddev->recovery);
463 
464 			dec_rdev = 0;
465 			if (test_bit(FailFast, &rdev->flags) &&
466 			    (bio->bi_opf & MD_FAILFAST)) {
467 				md_error(rdev->mddev, rdev);
468 			}
469 
470 			/*
471 			 * When the device is faulty, it is not necessary to
472 			 * handle write error.
473 			 */
474 			if (!test_bit(Faulty, &rdev->flags))
475 				set_bit(R10BIO_WriteError, &r10_bio->state);
476 			else {
477 				/* Fail the request */
478 				set_bit(R10BIO_Degraded, &r10_bio->state);
479 				r10_bio->devs[slot].bio = NULL;
480 				to_put = bio;
481 				dec_rdev = 1;
482 			}
483 		}
484 	} else {
485 		/*
486 		 * Set R10BIO_Uptodate in our master bio, so that
487 		 * we will return a good error code for to the higher
488 		 * levels even if IO on some other mirrored buffer fails.
489 		 *
490 		 * The 'master' represents the composite IO operation to
491 		 * user-side. So if something waits for IO, then it will
492 		 * wait for the 'master' bio.
493 		 */
494 		sector_t first_bad;
495 		int bad_sectors;
496 
497 		/*
498 		 * Do not set R10BIO_Uptodate if the current device is
499 		 * rebuilding or Faulty. This is because we cannot use
500 		 * such device for properly reading the data back (we could
501 		 * potentially use it, if the current write would have felt
502 		 * before rdev->recovery_offset, but for simplicity we don't
503 		 * check this here.
504 		 */
505 		if (test_bit(In_sync, &rdev->flags) &&
506 		    !test_bit(Faulty, &rdev->flags))
507 			set_bit(R10BIO_Uptodate, &r10_bio->state);
508 
509 		/* Maybe we can clear some bad blocks. */
510 		if (is_badblock(rdev,
511 				r10_bio->devs[slot].addr,
512 				r10_bio->sectors,
513 				&first_bad, &bad_sectors) && !discard_error) {
514 			bio_put(bio);
515 			if (repl)
516 				r10_bio->devs[slot].repl_bio = IO_MADE_GOOD;
517 			else
518 				r10_bio->devs[slot].bio = IO_MADE_GOOD;
519 			dec_rdev = 0;
520 			set_bit(R10BIO_MadeGood, &r10_bio->state);
521 		}
522 	}
523 
524 	/*
525 	 *
526 	 * Let's see if all mirrored write operations have finished
527 	 * already.
528 	 */
529 	one_write_done(r10_bio);
530 	if (dec_rdev)
531 		rdev_dec_pending(rdev, conf->mddev);
532 	if (to_put)
533 		bio_put(to_put);
534 }
535 
536 /*
537  * RAID10 layout manager
538  * As well as the chunksize and raid_disks count, there are two
539  * parameters: near_copies and far_copies.
540  * near_copies * far_copies must be <= raid_disks.
541  * Normally one of these will be 1.
542  * If both are 1, we get raid0.
543  * If near_copies == raid_disks, we get raid1.
544  *
545  * Chunks are laid out in raid0 style with near_copies copies of the
546  * first chunk, followed by near_copies copies of the next chunk and
547  * so on.
548  * If far_copies > 1, then after 1/far_copies of the array has been assigned
549  * as described above, we start again with a device offset of near_copies.
550  * So we effectively have another copy of the whole array further down all
551  * the drives, but with blocks on different drives.
552  * With this layout, and block is never stored twice on the one device.
553  *
554  * raid10_find_phys finds the sector offset of a given virtual sector
555  * on each device that it is on.
556  *
557  * raid10_find_virt does the reverse mapping, from a device and a
558  * sector offset to a virtual address
559  */
560 
__raid10_find_phys(struct geom * geo,struct r10bio * r10bio)561 static void __raid10_find_phys(struct geom *geo, struct r10bio *r10bio)
562 {
563 	int n,f;
564 	sector_t sector;
565 	sector_t chunk;
566 	sector_t stripe;
567 	int dev;
568 	int slot = 0;
569 	int last_far_set_start, last_far_set_size;
570 
571 	last_far_set_start = (geo->raid_disks / geo->far_set_size) - 1;
572 	last_far_set_start *= geo->far_set_size;
573 
574 	last_far_set_size = geo->far_set_size;
575 	last_far_set_size += (geo->raid_disks % geo->far_set_size);
576 
577 	/* now calculate first sector/dev */
578 	chunk = r10bio->sector >> geo->chunk_shift;
579 	sector = r10bio->sector & geo->chunk_mask;
580 
581 	chunk *= geo->near_copies;
582 	stripe = chunk;
583 	dev = sector_div(stripe, geo->raid_disks);
584 	if (geo->far_offset)
585 		stripe *= geo->far_copies;
586 
587 	sector += stripe << geo->chunk_shift;
588 
589 	/* and calculate all the others */
590 	for (n = 0; n < geo->near_copies; n++) {
591 		int d = dev;
592 		int set;
593 		sector_t s = sector;
594 		r10bio->devs[slot].devnum = d;
595 		r10bio->devs[slot].addr = s;
596 		slot++;
597 
598 		for (f = 1; f < geo->far_copies; f++) {
599 			set = d / geo->far_set_size;
600 			d += geo->near_copies;
601 
602 			if ((geo->raid_disks % geo->far_set_size) &&
603 			    (d > last_far_set_start)) {
604 				d -= last_far_set_start;
605 				d %= last_far_set_size;
606 				d += last_far_set_start;
607 			} else {
608 				d %= geo->far_set_size;
609 				d += geo->far_set_size * set;
610 			}
611 			s += geo->stride;
612 			r10bio->devs[slot].devnum = d;
613 			r10bio->devs[slot].addr = s;
614 			slot++;
615 		}
616 		dev++;
617 		if (dev >= geo->raid_disks) {
618 			dev = 0;
619 			sector += (geo->chunk_mask + 1);
620 		}
621 	}
622 }
623 
raid10_find_phys(struct r10conf * conf,struct r10bio * r10bio)624 static void raid10_find_phys(struct r10conf *conf, struct r10bio *r10bio)
625 {
626 	struct geom *geo = &conf->geo;
627 
628 	if (conf->reshape_progress != MaxSector &&
629 	    ((r10bio->sector >= conf->reshape_progress) !=
630 	     conf->mddev->reshape_backwards)) {
631 		set_bit(R10BIO_Previous, &r10bio->state);
632 		geo = &conf->prev;
633 	} else
634 		clear_bit(R10BIO_Previous, &r10bio->state);
635 
636 	__raid10_find_phys(geo, r10bio);
637 }
638 
raid10_find_virt(struct r10conf * conf,sector_t sector,int dev)639 static sector_t raid10_find_virt(struct r10conf *conf, sector_t sector, int dev)
640 {
641 	sector_t offset, chunk, vchunk;
642 	/* Never use conf->prev as this is only called during resync
643 	 * or recovery, so reshape isn't happening
644 	 */
645 	struct geom *geo = &conf->geo;
646 	int far_set_start = (dev / geo->far_set_size) * geo->far_set_size;
647 	int far_set_size = geo->far_set_size;
648 	int last_far_set_start;
649 
650 	if (geo->raid_disks % geo->far_set_size) {
651 		last_far_set_start = (geo->raid_disks / geo->far_set_size) - 1;
652 		last_far_set_start *= geo->far_set_size;
653 
654 		if (dev >= last_far_set_start) {
655 			far_set_size = geo->far_set_size;
656 			far_set_size += (geo->raid_disks % geo->far_set_size);
657 			far_set_start = last_far_set_start;
658 		}
659 	}
660 
661 	offset = sector & geo->chunk_mask;
662 	if (geo->far_offset) {
663 		int fc;
664 		chunk = sector >> geo->chunk_shift;
665 		fc = sector_div(chunk, geo->far_copies);
666 		dev -= fc * geo->near_copies;
667 		if (dev < far_set_start)
668 			dev += far_set_size;
669 	} else {
670 		while (sector >= geo->stride) {
671 			sector -= geo->stride;
672 			if (dev < (geo->near_copies + far_set_start))
673 				dev += far_set_size - geo->near_copies;
674 			else
675 				dev -= geo->near_copies;
676 		}
677 		chunk = sector >> geo->chunk_shift;
678 	}
679 	vchunk = chunk * geo->raid_disks + dev;
680 	sector_div(vchunk, geo->near_copies);
681 	return (vchunk << geo->chunk_shift) + offset;
682 }
683 
684 /*
685  * This routine returns the disk from which the requested read should
686  * be done. There is a per-array 'next expected sequential IO' sector
687  * number - if this matches on the next IO then we use the last disk.
688  * There is also a per-disk 'last know head position' sector that is
689  * maintained from IRQ contexts, both the normal and the resync IO
690  * completion handlers update this position correctly. If there is no
691  * perfect sequential match then we pick the disk whose head is closest.
692  *
693  * If there are 2 mirrors in the same 2 devices, performance degrades
694  * because position is mirror, not device based.
695  *
696  * The rdev for the device selected will have nr_pending incremented.
697  */
698 
699 /*
700  * FIXME: possibly should rethink readbalancing and do it differently
701  * depending on near_copies / far_copies geometry.
702  */
read_balance(struct r10conf * conf,struct r10bio * r10_bio,int * max_sectors)703 static struct md_rdev *read_balance(struct r10conf *conf,
704 				    struct r10bio *r10_bio,
705 				    int *max_sectors)
706 {
707 	const sector_t this_sector = r10_bio->sector;
708 	int disk, slot;
709 	int sectors = r10_bio->sectors;
710 	int best_good_sectors;
711 	sector_t new_distance, best_dist;
712 	struct md_rdev *best_dist_rdev, *best_pending_rdev, *rdev = NULL;
713 	int do_balance;
714 	int best_dist_slot, best_pending_slot;
715 	bool has_nonrot_disk = false;
716 	unsigned int min_pending;
717 	struct geom *geo = &conf->geo;
718 
719 	raid10_find_phys(conf, r10_bio);
720 	rcu_read_lock();
721 	best_dist_slot = -1;
722 	min_pending = UINT_MAX;
723 	best_dist_rdev = NULL;
724 	best_pending_rdev = NULL;
725 	best_dist = MaxSector;
726 	best_good_sectors = 0;
727 	do_balance = 1;
728 	clear_bit(R10BIO_FailFast, &r10_bio->state);
729 	/*
730 	 * Check if we can balance. We can balance on the whole
731 	 * device if no resync is going on (recovery is ok), or below
732 	 * the resync window. We take the first readable disk when
733 	 * above the resync window.
734 	 */
735 	if ((conf->mddev->recovery_cp < MaxSector
736 	     && (this_sector + sectors >= conf->next_resync)) ||
737 	    (mddev_is_clustered(conf->mddev) &&
738 	     md_cluster_ops->area_resyncing(conf->mddev, READ, this_sector,
739 					    this_sector + sectors)))
740 		do_balance = 0;
741 
742 	for (slot = 0; slot < conf->copies ; slot++) {
743 		sector_t first_bad;
744 		int bad_sectors;
745 		sector_t dev_sector;
746 		unsigned int pending;
747 		bool nonrot;
748 
749 		if (r10_bio->devs[slot].bio == IO_BLOCKED)
750 			continue;
751 		disk = r10_bio->devs[slot].devnum;
752 		rdev = rcu_dereference(conf->mirrors[disk].replacement);
753 		if (rdev == NULL || test_bit(Faulty, &rdev->flags) ||
754 		    r10_bio->devs[slot].addr + sectors > rdev->recovery_offset)
755 			rdev = rcu_dereference(conf->mirrors[disk].rdev);
756 		if (rdev == NULL ||
757 		    test_bit(Faulty, &rdev->flags))
758 			continue;
759 		if (!test_bit(In_sync, &rdev->flags) &&
760 		    r10_bio->devs[slot].addr + sectors > rdev->recovery_offset)
761 			continue;
762 
763 		dev_sector = r10_bio->devs[slot].addr;
764 		if (is_badblock(rdev, dev_sector, sectors,
765 				&first_bad, &bad_sectors)) {
766 			if (best_dist < MaxSector)
767 				/* Already have a better slot */
768 				continue;
769 			if (first_bad <= dev_sector) {
770 				/* Cannot read here.  If this is the
771 				 * 'primary' device, then we must not read
772 				 * beyond 'bad_sectors' from another device.
773 				 */
774 				bad_sectors -= (dev_sector - first_bad);
775 				if (!do_balance && sectors > bad_sectors)
776 					sectors = bad_sectors;
777 				if (best_good_sectors > sectors)
778 					best_good_sectors = sectors;
779 			} else {
780 				sector_t good_sectors =
781 					first_bad - dev_sector;
782 				if (good_sectors > best_good_sectors) {
783 					best_good_sectors = good_sectors;
784 					best_dist_slot = slot;
785 					best_dist_rdev = rdev;
786 				}
787 				if (!do_balance)
788 					/* Must read from here */
789 					break;
790 			}
791 			continue;
792 		} else
793 			best_good_sectors = sectors;
794 
795 		if (!do_balance)
796 			break;
797 
798 		nonrot = blk_queue_nonrot(bdev_get_queue(rdev->bdev));
799 		has_nonrot_disk |= nonrot;
800 		pending = atomic_read(&rdev->nr_pending);
801 		if (min_pending > pending && nonrot) {
802 			min_pending = pending;
803 			best_pending_slot = slot;
804 			best_pending_rdev = rdev;
805 		}
806 
807 		if (best_dist_slot >= 0)
808 			/* At least 2 disks to choose from so failfast is OK */
809 			set_bit(R10BIO_FailFast, &r10_bio->state);
810 		/* This optimisation is debatable, and completely destroys
811 		 * sequential read speed for 'far copies' arrays.  So only
812 		 * keep it for 'near' arrays, and review those later.
813 		 */
814 		if (geo->near_copies > 1 && !pending)
815 			new_distance = 0;
816 
817 		/* for far > 1 always use the lowest address */
818 		else if (geo->far_copies > 1)
819 			new_distance = r10_bio->devs[slot].addr;
820 		else
821 			new_distance = abs(r10_bio->devs[slot].addr -
822 					   conf->mirrors[disk].head_position);
823 
824 		if (new_distance < best_dist) {
825 			best_dist = new_distance;
826 			best_dist_slot = slot;
827 			best_dist_rdev = rdev;
828 		}
829 	}
830 	if (slot >= conf->copies) {
831 		if (has_nonrot_disk) {
832 			slot = best_pending_slot;
833 			rdev = best_pending_rdev;
834 		} else {
835 			slot = best_dist_slot;
836 			rdev = best_dist_rdev;
837 		}
838 	}
839 
840 	if (slot >= 0) {
841 		atomic_inc(&rdev->nr_pending);
842 		r10_bio->read_slot = slot;
843 	} else
844 		rdev = NULL;
845 	rcu_read_unlock();
846 	*max_sectors = best_good_sectors;
847 
848 	return rdev;
849 }
850 
flush_pending_writes(struct r10conf * conf)851 static void flush_pending_writes(struct r10conf *conf)
852 {
853 	/* Any writes that have been queued but are awaiting
854 	 * bitmap updates get flushed here.
855 	 */
856 	spin_lock_irq(&conf->device_lock);
857 
858 	if (conf->pending_bio_list.head) {
859 		struct blk_plug plug;
860 		struct bio *bio;
861 
862 		bio = bio_list_get(&conf->pending_bio_list);
863 		conf->pending_count = 0;
864 		spin_unlock_irq(&conf->device_lock);
865 
866 		/*
867 		 * As this is called in a wait_event() loop (see freeze_array),
868 		 * current->state might be TASK_UNINTERRUPTIBLE which will
869 		 * cause a warning when we prepare to wait again.  As it is
870 		 * rare that this path is taken, it is perfectly safe to force
871 		 * us to go around the wait_event() loop again, so the warning
872 		 * is a false-positive. Silence the warning by resetting
873 		 * thread state
874 		 */
875 		__set_current_state(TASK_RUNNING);
876 
877 		blk_start_plug(&plug);
878 		/* flush any pending bitmap writes to disk
879 		 * before proceeding w/ I/O */
880 		md_bitmap_unplug(conf->mddev->bitmap);
881 		wake_up(&conf->wait_barrier);
882 
883 		while (bio) { /* submit pending writes */
884 			struct bio *next = bio->bi_next;
885 			struct md_rdev *rdev = (void*)bio->bi_disk;
886 			bio->bi_next = NULL;
887 			bio_set_dev(bio, rdev->bdev);
888 			if (test_bit(Faulty, &rdev->flags)) {
889 				bio_io_error(bio);
890 			} else if (unlikely((bio_op(bio) ==  REQ_OP_DISCARD) &&
891 					    !blk_queue_discard(bio->bi_disk->queue)))
892 				/* Just ignore it */
893 				bio_endio(bio);
894 			else
895 				submit_bio_noacct(bio);
896 			bio = next;
897 		}
898 		blk_finish_plug(&plug);
899 	} else
900 		spin_unlock_irq(&conf->device_lock);
901 }
902 
903 /* Barriers....
904  * Sometimes we need to suspend IO while we do something else,
905  * either some resync/recovery, or reconfigure the array.
906  * To do this we raise a 'barrier'.
907  * The 'barrier' is a counter that can be raised multiple times
908  * to count how many activities are happening which preclude
909  * normal IO.
910  * We can only raise the barrier if there is no pending IO.
911  * i.e. if nr_pending == 0.
912  * We choose only to raise the barrier if no-one is waiting for the
913  * barrier to go down.  This means that as soon as an IO request
914  * is ready, no other operations which require a barrier will start
915  * until the IO request has had a chance.
916  *
917  * So: regular IO calls 'wait_barrier'.  When that returns there
918  *    is no backgroup IO happening,  It must arrange to call
919  *    allow_barrier when it has finished its IO.
920  * backgroup IO calls must call raise_barrier.  Once that returns
921  *    there is no normal IO happeing.  It must arrange to call
922  *    lower_barrier when the particular background IO completes.
923  */
924 
raise_barrier(struct r10conf * conf,int force)925 static void raise_barrier(struct r10conf *conf, int force)
926 {
927 	BUG_ON(force && !conf->barrier);
928 	spin_lock_irq(&conf->resync_lock);
929 
930 	/* Wait until no block IO is waiting (unless 'force') */
931 	wait_event_lock_irq(conf->wait_barrier, force || !conf->nr_waiting,
932 			    conf->resync_lock);
933 
934 	/* block any new IO from starting */
935 	conf->barrier++;
936 
937 	/* Now wait for all pending IO to complete */
938 	wait_event_lock_irq(conf->wait_barrier,
939 			    !atomic_read(&conf->nr_pending) && conf->barrier < RESYNC_DEPTH,
940 			    conf->resync_lock);
941 
942 	spin_unlock_irq(&conf->resync_lock);
943 }
944 
lower_barrier(struct r10conf * conf)945 static void lower_barrier(struct r10conf *conf)
946 {
947 	unsigned long flags;
948 	spin_lock_irqsave(&conf->resync_lock, flags);
949 	conf->barrier--;
950 	spin_unlock_irqrestore(&conf->resync_lock, flags);
951 	wake_up(&conf->wait_barrier);
952 }
953 
wait_barrier(struct r10conf * conf)954 static void wait_barrier(struct r10conf *conf)
955 {
956 	spin_lock_irq(&conf->resync_lock);
957 	if (conf->barrier) {
958 		struct bio_list *bio_list = current->bio_list;
959 		conf->nr_waiting++;
960 		/* Wait for the barrier to drop.
961 		 * However if there are already pending
962 		 * requests (preventing the barrier from
963 		 * rising completely), and the
964 		 * pre-process bio queue isn't empty,
965 		 * then don't wait, as we need to empty
966 		 * that queue to get the nr_pending
967 		 * count down.
968 		 */
969 		raid10_log(conf->mddev, "wait barrier");
970 		wait_event_lock_irq(conf->wait_barrier,
971 				    !conf->barrier ||
972 				    (atomic_read(&conf->nr_pending) &&
973 				     bio_list &&
974 				     (!bio_list_empty(&bio_list[0]) ||
975 				      !bio_list_empty(&bio_list[1]))) ||
976 				     /* move on if recovery thread is
977 				      * blocked by us
978 				      */
979 				     (conf->mddev->thread->tsk == current &&
980 				      test_bit(MD_RECOVERY_RUNNING,
981 					       &conf->mddev->recovery) &&
982 				      conf->nr_queued > 0),
983 				    conf->resync_lock);
984 		conf->nr_waiting--;
985 		if (!conf->nr_waiting)
986 			wake_up(&conf->wait_barrier);
987 	}
988 	atomic_inc(&conf->nr_pending);
989 	spin_unlock_irq(&conf->resync_lock);
990 }
991 
allow_barrier(struct r10conf * conf)992 static void allow_barrier(struct r10conf *conf)
993 {
994 	if ((atomic_dec_and_test(&conf->nr_pending)) ||
995 			(conf->array_freeze_pending))
996 		wake_up(&conf->wait_barrier);
997 }
998 
freeze_array(struct r10conf * conf,int extra)999 static void freeze_array(struct r10conf *conf, int extra)
1000 {
1001 	/* stop syncio and normal IO and wait for everything to
1002 	 * go quiet.
1003 	 * We increment barrier and nr_waiting, and then
1004 	 * wait until nr_pending match nr_queued+extra
1005 	 * This is called in the context of one normal IO request
1006 	 * that has failed. Thus any sync request that might be pending
1007 	 * will be blocked by nr_pending, and we need to wait for
1008 	 * pending IO requests to complete or be queued for re-try.
1009 	 * Thus the number queued (nr_queued) plus this request (extra)
1010 	 * must match the number of pending IOs (nr_pending) before
1011 	 * we continue.
1012 	 */
1013 	spin_lock_irq(&conf->resync_lock);
1014 	conf->array_freeze_pending++;
1015 	conf->barrier++;
1016 	conf->nr_waiting++;
1017 	wait_event_lock_irq_cmd(conf->wait_barrier,
1018 				atomic_read(&conf->nr_pending) == conf->nr_queued+extra,
1019 				conf->resync_lock,
1020 				flush_pending_writes(conf));
1021 
1022 	conf->array_freeze_pending--;
1023 	spin_unlock_irq(&conf->resync_lock);
1024 }
1025 
unfreeze_array(struct r10conf * conf)1026 static void unfreeze_array(struct r10conf *conf)
1027 {
1028 	/* reverse the effect of the freeze */
1029 	spin_lock_irq(&conf->resync_lock);
1030 	conf->barrier--;
1031 	conf->nr_waiting--;
1032 	wake_up(&conf->wait_barrier);
1033 	spin_unlock_irq(&conf->resync_lock);
1034 }
1035 
choose_data_offset(struct r10bio * r10_bio,struct md_rdev * rdev)1036 static sector_t choose_data_offset(struct r10bio *r10_bio,
1037 				   struct md_rdev *rdev)
1038 {
1039 	if (!test_bit(MD_RECOVERY_RESHAPE, &rdev->mddev->recovery) ||
1040 	    test_bit(R10BIO_Previous, &r10_bio->state))
1041 		return rdev->data_offset;
1042 	else
1043 		return rdev->new_data_offset;
1044 }
1045 
1046 struct raid10_plug_cb {
1047 	struct blk_plug_cb	cb;
1048 	struct bio_list		pending;
1049 	int			pending_cnt;
1050 };
1051 
raid10_unplug(struct blk_plug_cb * cb,bool from_schedule)1052 static void raid10_unplug(struct blk_plug_cb *cb, bool from_schedule)
1053 {
1054 	struct raid10_plug_cb *plug = container_of(cb, struct raid10_plug_cb,
1055 						   cb);
1056 	struct mddev *mddev = plug->cb.data;
1057 	struct r10conf *conf = mddev->private;
1058 	struct bio *bio;
1059 
1060 	if (from_schedule || current->bio_list) {
1061 		spin_lock_irq(&conf->device_lock);
1062 		bio_list_merge(&conf->pending_bio_list, &plug->pending);
1063 		conf->pending_count += plug->pending_cnt;
1064 		spin_unlock_irq(&conf->device_lock);
1065 		wake_up(&conf->wait_barrier);
1066 		md_wakeup_thread(mddev->thread);
1067 		kfree(plug);
1068 		return;
1069 	}
1070 
1071 	/* we aren't scheduling, so we can do the write-out directly. */
1072 	bio = bio_list_get(&plug->pending);
1073 	md_bitmap_unplug(mddev->bitmap);
1074 	wake_up(&conf->wait_barrier);
1075 
1076 	while (bio) { /* submit pending writes */
1077 		struct bio *next = bio->bi_next;
1078 		struct md_rdev *rdev = (void*)bio->bi_disk;
1079 		bio->bi_next = NULL;
1080 		bio_set_dev(bio, rdev->bdev);
1081 		if (test_bit(Faulty, &rdev->flags)) {
1082 			bio_io_error(bio);
1083 		} else if (unlikely((bio_op(bio) ==  REQ_OP_DISCARD) &&
1084 				    !blk_queue_discard(bio->bi_disk->queue)))
1085 			/* Just ignore it */
1086 			bio_endio(bio);
1087 		else
1088 			submit_bio_noacct(bio);
1089 		bio = next;
1090 	}
1091 	kfree(plug);
1092 }
1093 
1094 /*
1095  * 1. Register the new request and wait if the reconstruction thread has put
1096  * up a bar for new requests. Continue immediately if no resync is active
1097  * currently.
1098  * 2. If IO spans the reshape position.  Need to wait for reshape to pass.
1099  */
regular_request_wait(struct mddev * mddev,struct r10conf * conf,struct bio * bio,sector_t sectors)1100 static void regular_request_wait(struct mddev *mddev, struct r10conf *conf,
1101 				 struct bio *bio, sector_t sectors)
1102 {
1103 	wait_barrier(conf);
1104 	while (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery) &&
1105 	    bio->bi_iter.bi_sector < conf->reshape_progress &&
1106 	    bio->bi_iter.bi_sector + sectors > conf->reshape_progress) {
1107 		raid10_log(conf->mddev, "wait reshape");
1108 		allow_barrier(conf);
1109 		wait_event(conf->wait_barrier,
1110 			   conf->reshape_progress <= bio->bi_iter.bi_sector ||
1111 			   conf->reshape_progress >= bio->bi_iter.bi_sector +
1112 			   sectors);
1113 		wait_barrier(conf);
1114 	}
1115 }
1116 
raid10_read_request(struct mddev * mddev,struct bio * bio,struct r10bio * r10_bio)1117 static void raid10_read_request(struct mddev *mddev, struct bio *bio,
1118 				struct r10bio *r10_bio)
1119 {
1120 	struct r10conf *conf = mddev->private;
1121 	struct bio *read_bio;
1122 	const int op = bio_op(bio);
1123 	const unsigned long do_sync = (bio->bi_opf & REQ_SYNC);
1124 	int max_sectors;
1125 	struct md_rdev *rdev;
1126 	char b[BDEVNAME_SIZE];
1127 	int slot = r10_bio->read_slot;
1128 	struct md_rdev *err_rdev = NULL;
1129 	gfp_t gfp = GFP_NOIO;
1130 
1131 	if (slot >= 0 && r10_bio->devs[slot].rdev) {
1132 		/*
1133 		 * This is an error retry, but we cannot
1134 		 * safely dereference the rdev in the r10_bio,
1135 		 * we must use the one in conf.
1136 		 * If it has already been disconnected (unlikely)
1137 		 * we lose the device name in error messages.
1138 		 */
1139 		int disk;
1140 		/*
1141 		 * As we are blocking raid10, it is a little safer to
1142 		 * use __GFP_HIGH.
1143 		 */
1144 		gfp = GFP_NOIO | __GFP_HIGH;
1145 
1146 		rcu_read_lock();
1147 		disk = r10_bio->devs[slot].devnum;
1148 		err_rdev = rcu_dereference(conf->mirrors[disk].rdev);
1149 		if (err_rdev)
1150 			bdevname(err_rdev->bdev, b);
1151 		else {
1152 			strcpy(b, "???");
1153 			/* This never gets dereferenced */
1154 			err_rdev = r10_bio->devs[slot].rdev;
1155 		}
1156 		rcu_read_unlock();
1157 	}
1158 
1159 	regular_request_wait(mddev, conf, bio, r10_bio->sectors);
1160 	rdev = read_balance(conf, r10_bio, &max_sectors);
1161 	if (!rdev) {
1162 		if (err_rdev) {
1163 			pr_crit_ratelimited("md/raid10:%s: %s: unrecoverable I/O read error for block %llu\n",
1164 					    mdname(mddev), b,
1165 					    (unsigned long long)r10_bio->sector);
1166 		}
1167 		raid_end_bio_io(r10_bio);
1168 		return;
1169 	}
1170 	if (err_rdev)
1171 		pr_err_ratelimited("md/raid10:%s: %s: redirecting sector %llu to another mirror\n",
1172 				   mdname(mddev),
1173 				   bdevname(rdev->bdev, b),
1174 				   (unsigned long long)r10_bio->sector);
1175 	if (max_sectors < bio_sectors(bio)) {
1176 		struct bio *split = bio_split(bio, max_sectors,
1177 					      gfp, &conf->bio_split);
1178 		bio_chain(split, bio);
1179 		allow_barrier(conf);
1180 		submit_bio_noacct(bio);
1181 		wait_barrier(conf);
1182 		bio = split;
1183 		r10_bio->master_bio = bio;
1184 		r10_bio->sectors = max_sectors;
1185 	}
1186 	slot = r10_bio->read_slot;
1187 
1188 	read_bio = bio_clone_fast(bio, gfp, &mddev->bio_set);
1189 
1190 	r10_bio->devs[slot].bio = read_bio;
1191 	r10_bio->devs[slot].rdev = rdev;
1192 
1193 	read_bio->bi_iter.bi_sector = r10_bio->devs[slot].addr +
1194 		choose_data_offset(r10_bio, rdev);
1195 	bio_set_dev(read_bio, rdev->bdev);
1196 	read_bio->bi_end_io = raid10_end_read_request;
1197 	bio_set_op_attrs(read_bio, op, do_sync);
1198 	if (test_bit(FailFast, &rdev->flags) &&
1199 	    test_bit(R10BIO_FailFast, &r10_bio->state))
1200 	        read_bio->bi_opf |= MD_FAILFAST;
1201 	read_bio->bi_private = r10_bio;
1202 
1203 	if (mddev->gendisk)
1204 	        trace_block_bio_remap(read_bio->bi_disk->queue,
1205 	                              read_bio, disk_devt(mddev->gendisk),
1206 	                              r10_bio->sector);
1207 	submit_bio_noacct(read_bio);
1208 	return;
1209 }
1210 
raid10_write_one_disk(struct mddev * mddev,struct r10bio * r10_bio,struct bio * bio,bool replacement,int n_copy)1211 static void raid10_write_one_disk(struct mddev *mddev, struct r10bio *r10_bio,
1212 				  struct bio *bio, bool replacement,
1213 				  int n_copy)
1214 {
1215 	const int op = bio_op(bio);
1216 	const unsigned long do_sync = (bio->bi_opf & REQ_SYNC);
1217 	const unsigned long do_fua = (bio->bi_opf & REQ_FUA);
1218 	unsigned long flags;
1219 	struct blk_plug_cb *cb;
1220 	struct raid10_plug_cb *plug = NULL;
1221 	struct r10conf *conf = mddev->private;
1222 	struct md_rdev *rdev;
1223 	int devnum = r10_bio->devs[n_copy].devnum;
1224 	struct bio *mbio;
1225 
1226 	if (replacement) {
1227 		rdev = conf->mirrors[devnum].replacement;
1228 		if (rdev == NULL) {
1229 			/* Replacement just got moved to main 'rdev' */
1230 			smp_mb();
1231 			rdev = conf->mirrors[devnum].rdev;
1232 		}
1233 	} else
1234 		rdev = conf->mirrors[devnum].rdev;
1235 
1236 	mbio = bio_clone_fast(bio, GFP_NOIO, &mddev->bio_set);
1237 	if (replacement)
1238 		r10_bio->devs[n_copy].repl_bio = mbio;
1239 	else
1240 		r10_bio->devs[n_copy].bio = mbio;
1241 
1242 	mbio->bi_iter.bi_sector	= (r10_bio->devs[n_copy].addr +
1243 				   choose_data_offset(r10_bio, rdev));
1244 	bio_set_dev(mbio, rdev->bdev);
1245 	mbio->bi_end_io	= raid10_end_write_request;
1246 	bio_set_op_attrs(mbio, op, do_sync | do_fua);
1247 	if (!replacement && test_bit(FailFast,
1248 				     &conf->mirrors[devnum].rdev->flags)
1249 			 && enough(conf, devnum))
1250 		mbio->bi_opf |= MD_FAILFAST;
1251 	mbio->bi_private = r10_bio;
1252 
1253 	if (conf->mddev->gendisk)
1254 		trace_block_bio_remap(mbio->bi_disk->queue,
1255 				      mbio, disk_devt(conf->mddev->gendisk),
1256 				      r10_bio->sector);
1257 	/* flush_pending_writes() needs access to the rdev so...*/
1258 	mbio->bi_disk = (void *)rdev;
1259 
1260 	atomic_inc(&r10_bio->remaining);
1261 
1262 	cb = blk_check_plugged(raid10_unplug, mddev, sizeof(*plug));
1263 	if (cb)
1264 		plug = container_of(cb, struct raid10_plug_cb, cb);
1265 	else
1266 		plug = NULL;
1267 	if (plug) {
1268 		bio_list_add(&plug->pending, mbio);
1269 		plug->pending_cnt++;
1270 	} else {
1271 		spin_lock_irqsave(&conf->device_lock, flags);
1272 		bio_list_add(&conf->pending_bio_list, mbio);
1273 		conf->pending_count++;
1274 		spin_unlock_irqrestore(&conf->device_lock, flags);
1275 		md_wakeup_thread(mddev->thread);
1276 	}
1277 }
1278 
raid10_write_request(struct mddev * mddev,struct bio * bio,struct r10bio * r10_bio)1279 static void raid10_write_request(struct mddev *mddev, struct bio *bio,
1280 				 struct r10bio *r10_bio)
1281 {
1282 	struct r10conf *conf = mddev->private;
1283 	int i;
1284 	struct md_rdev *blocked_rdev;
1285 	sector_t sectors;
1286 	int max_sectors;
1287 
1288 	if ((mddev_is_clustered(mddev) &&
1289 	     md_cluster_ops->area_resyncing(mddev, WRITE,
1290 					    bio->bi_iter.bi_sector,
1291 					    bio_end_sector(bio)))) {
1292 		DEFINE_WAIT(w);
1293 		for (;;) {
1294 			prepare_to_wait(&conf->wait_barrier,
1295 					&w, TASK_IDLE);
1296 			if (!md_cluster_ops->area_resyncing(mddev, WRITE,
1297 				 bio->bi_iter.bi_sector, bio_end_sector(bio)))
1298 				break;
1299 			schedule();
1300 		}
1301 		finish_wait(&conf->wait_barrier, &w);
1302 	}
1303 
1304 	sectors = r10_bio->sectors;
1305 	regular_request_wait(mddev, conf, bio, sectors);
1306 	if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery) &&
1307 	    (mddev->reshape_backwards
1308 	     ? (bio->bi_iter.bi_sector < conf->reshape_safe &&
1309 		bio->bi_iter.bi_sector + sectors > conf->reshape_progress)
1310 	     : (bio->bi_iter.bi_sector + sectors > conf->reshape_safe &&
1311 		bio->bi_iter.bi_sector < conf->reshape_progress))) {
1312 		/* Need to update reshape_position in metadata */
1313 		mddev->reshape_position = conf->reshape_progress;
1314 		set_mask_bits(&mddev->sb_flags, 0,
1315 			      BIT(MD_SB_CHANGE_DEVS) | BIT(MD_SB_CHANGE_PENDING));
1316 		md_wakeup_thread(mddev->thread);
1317 		raid10_log(conf->mddev, "wait reshape metadata");
1318 		wait_event(mddev->sb_wait,
1319 			   !test_bit(MD_SB_CHANGE_PENDING, &mddev->sb_flags));
1320 
1321 		conf->reshape_safe = mddev->reshape_position;
1322 	}
1323 
1324 	if (conf->pending_count >= max_queued_requests) {
1325 		md_wakeup_thread(mddev->thread);
1326 		raid10_log(mddev, "wait queued");
1327 		wait_event(conf->wait_barrier,
1328 			   conf->pending_count < max_queued_requests);
1329 	}
1330 	/* first select target devices under rcu_lock and
1331 	 * inc refcount on their rdev.  Record them by setting
1332 	 * bios[x] to bio
1333 	 * If there are known/acknowledged bad blocks on any device
1334 	 * on which we have seen a write error, we want to avoid
1335 	 * writing to those blocks.  This potentially requires several
1336 	 * writes to write around the bad blocks.  Each set of writes
1337 	 * gets its own r10_bio with a set of bios attached.
1338 	 */
1339 
1340 	r10_bio->read_slot = -1; /* make sure repl_bio gets freed */
1341 	raid10_find_phys(conf, r10_bio);
1342 retry_write:
1343 	blocked_rdev = NULL;
1344 	rcu_read_lock();
1345 	max_sectors = r10_bio->sectors;
1346 
1347 	for (i = 0;  i < conf->copies; i++) {
1348 		int d = r10_bio->devs[i].devnum;
1349 		struct md_rdev *rdev = rcu_dereference(conf->mirrors[d].rdev);
1350 		struct md_rdev *rrdev = rcu_dereference(
1351 			conf->mirrors[d].replacement);
1352 		if (rdev == rrdev)
1353 			rrdev = NULL;
1354 		if (rdev && unlikely(test_bit(Blocked, &rdev->flags))) {
1355 			atomic_inc(&rdev->nr_pending);
1356 			blocked_rdev = rdev;
1357 			break;
1358 		}
1359 		if (rrdev && unlikely(test_bit(Blocked, &rrdev->flags))) {
1360 			atomic_inc(&rrdev->nr_pending);
1361 			blocked_rdev = rrdev;
1362 			break;
1363 		}
1364 		if (rdev && (test_bit(Faulty, &rdev->flags)))
1365 			rdev = NULL;
1366 		if (rrdev && (test_bit(Faulty, &rrdev->flags)))
1367 			rrdev = NULL;
1368 
1369 		r10_bio->devs[i].bio = NULL;
1370 		r10_bio->devs[i].repl_bio = NULL;
1371 
1372 		if (!rdev && !rrdev) {
1373 			set_bit(R10BIO_Degraded, &r10_bio->state);
1374 			continue;
1375 		}
1376 		if (rdev && test_bit(WriteErrorSeen, &rdev->flags)) {
1377 			sector_t first_bad;
1378 			sector_t dev_sector = r10_bio->devs[i].addr;
1379 			int bad_sectors;
1380 			int is_bad;
1381 
1382 			is_bad = is_badblock(rdev, dev_sector, max_sectors,
1383 					     &first_bad, &bad_sectors);
1384 			if (is_bad < 0) {
1385 				/* Mustn't write here until the bad block
1386 				 * is acknowledged
1387 				 */
1388 				atomic_inc(&rdev->nr_pending);
1389 				set_bit(BlockedBadBlocks, &rdev->flags);
1390 				blocked_rdev = rdev;
1391 				break;
1392 			}
1393 			if (is_bad && first_bad <= dev_sector) {
1394 				/* Cannot write here at all */
1395 				bad_sectors -= (dev_sector - first_bad);
1396 				if (bad_sectors < max_sectors)
1397 					/* Mustn't write more than bad_sectors
1398 					 * to other devices yet
1399 					 */
1400 					max_sectors = bad_sectors;
1401 				/* We don't set R10BIO_Degraded as that
1402 				 * only applies if the disk is missing,
1403 				 * so it might be re-added, and we want to
1404 				 * know to recover this chunk.
1405 				 * In this case the device is here, and the
1406 				 * fact that this chunk is not in-sync is
1407 				 * recorded in the bad block log.
1408 				 */
1409 				continue;
1410 			}
1411 			if (is_bad) {
1412 				int good_sectors = first_bad - dev_sector;
1413 				if (good_sectors < max_sectors)
1414 					max_sectors = good_sectors;
1415 			}
1416 		}
1417 		if (rdev) {
1418 			r10_bio->devs[i].bio = bio;
1419 			atomic_inc(&rdev->nr_pending);
1420 		}
1421 		if (rrdev) {
1422 			r10_bio->devs[i].repl_bio = bio;
1423 			atomic_inc(&rrdev->nr_pending);
1424 		}
1425 	}
1426 	rcu_read_unlock();
1427 
1428 	if (unlikely(blocked_rdev)) {
1429 		/* Have to wait for this device to get unblocked, then retry */
1430 		int j;
1431 		int d;
1432 
1433 		for (j = 0; j < i; j++) {
1434 			if (r10_bio->devs[j].bio) {
1435 				d = r10_bio->devs[j].devnum;
1436 				rdev_dec_pending(conf->mirrors[d].rdev, mddev);
1437 			}
1438 			if (r10_bio->devs[j].repl_bio) {
1439 				struct md_rdev *rdev;
1440 				d = r10_bio->devs[j].devnum;
1441 				rdev = conf->mirrors[d].replacement;
1442 				if (!rdev) {
1443 					/* Race with remove_disk */
1444 					smp_mb();
1445 					rdev = conf->mirrors[d].rdev;
1446 				}
1447 				rdev_dec_pending(rdev, mddev);
1448 			}
1449 		}
1450 		allow_barrier(conf);
1451 		raid10_log(conf->mddev, "wait rdev %d blocked", blocked_rdev->raid_disk);
1452 		md_wait_for_blocked_rdev(blocked_rdev, mddev);
1453 		wait_barrier(conf);
1454 		goto retry_write;
1455 	}
1456 
1457 	if (max_sectors < r10_bio->sectors)
1458 		r10_bio->sectors = max_sectors;
1459 
1460 	if (r10_bio->sectors < bio_sectors(bio)) {
1461 		struct bio *split = bio_split(bio, r10_bio->sectors,
1462 					      GFP_NOIO, &conf->bio_split);
1463 		bio_chain(split, bio);
1464 		allow_barrier(conf);
1465 		submit_bio_noacct(bio);
1466 		wait_barrier(conf);
1467 		bio = split;
1468 		r10_bio->master_bio = bio;
1469 	}
1470 
1471 	atomic_set(&r10_bio->remaining, 1);
1472 	md_bitmap_startwrite(mddev->bitmap, r10_bio->sector, r10_bio->sectors, 0);
1473 
1474 	for (i = 0; i < conf->copies; i++) {
1475 		if (r10_bio->devs[i].bio)
1476 			raid10_write_one_disk(mddev, r10_bio, bio, false, i);
1477 		if (r10_bio->devs[i].repl_bio)
1478 			raid10_write_one_disk(mddev, r10_bio, bio, true, i);
1479 	}
1480 	one_write_done(r10_bio);
1481 }
1482 
__make_request(struct mddev * mddev,struct bio * bio,int sectors)1483 static void __make_request(struct mddev *mddev, struct bio *bio, int sectors)
1484 {
1485 	struct r10conf *conf = mddev->private;
1486 	struct r10bio *r10_bio;
1487 
1488 	r10_bio = mempool_alloc(&conf->r10bio_pool, GFP_NOIO);
1489 
1490 	r10_bio->master_bio = bio;
1491 	r10_bio->sectors = sectors;
1492 
1493 	r10_bio->mddev = mddev;
1494 	r10_bio->sector = bio->bi_iter.bi_sector;
1495 	r10_bio->state = 0;
1496 	r10_bio->read_slot = -1;
1497 	memset(r10_bio->devs, 0, sizeof(r10_bio->devs[0]) * conf->copies);
1498 
1499 	if (bio_data_dir(bio) == READ)
1500 		raid10_read_request(mddev, bio, r10_bio);
1501 	else
1502 		raid10_write_request(mddev, bio, r10_bio);
1503 }
1504 
raid10_make_request(struct mddev * mddev,struct bio * bio)1505 static bool raid10_make_request(struct mddev *mddev, struct bio *bio)
1506 {
1507 	struct r10conf *conf = mddev->private;
1508 	sector_t chunk_mask = (conf->geo.chunk_mask & conf->prev.chunk_mask);
1509 	int chunk_sects = chunk_mask + 1;
1510 	int sectors = bio_sectors(bio);
1511 
1512 	if (unlikely(bio->bi_opf & REQ_PREFLUSH)
1513 	    && md_flush_request(mddev, bio))
1514 		return true;
1515 
1516 	if (!md_write_start(mddev, bio))
1517 		return false;
1518 
1519 	/*
1520 	 * If this request crosses a chunk boundary, we need to split
1521 	 * it.
1522 	 */
1523 	if (unlikely((bio->bi_iter.bi_sector & chunk_mask) +
1524 		     sectors > chunk_sects
1525 		     && (conf->geo.near_copies < conf->geo.raid_disks
1526 			 || conf->prev.near_copies <
1527 			 conf->prev.raid_disks)))
1528 		sectors = chunk_sects -
1529 			(bio->bi_iter.bi_sector &
1530 			 (chunk_sects - 1));
1531 	__make_request(mddev, bio, sectors);
1532 
1533 	/* In case raid10d snuck in to freeze_array */
1534 	wake_up(&conf->wait_barrier);
1535 	return true;
1536 }
1537 
raid10_status(struct seq_file * seq,struct mddev * mddev)1538 static void raid10_status(struct seq_file *seq, struct mddev *mddev)
1539 {
1540 	struct r10conf *conf = mddev->private;
1541 	int i;
1542 
1543 	if (conf->geo.near_copies < conf->geo.raid_disks)
1544 		seq_printf(seq, " %dK chunks", mddev->chunk_sectors / 2);
1545 	if (conf->geo.near_copies > 1)
1546 		seq_printf(seq, " %d near-copies", conf->geo.near_copies);
1547 	if (conf->geo.far_copies > 1) {
1548 		if (conf->geo.far_offset)
1549 			seq_printf(seq, " %d offset-copies", conf->geo.far_copies);
1550 		else
1551 			seq_printf(seq, " %d far-copies", conf->geo.far_copies);
1552 		if (conf->geo.far_set_size != conf->geo.raid_disks)
1553 			seq_printf(seq, " %d devices per set", conf->geo.far_set_size);
1554 	}
1555 	seq_printf(seq, " [%d/%d] [", conf->geo.raid_disks,
1556 					conf->geo.raid_disks - mddev->degraded);
1557 	rcu_read_lock();
1558 	for (i = 0; i < conf->geo.raid_disks; i++) {
1559 		struct md_rdev *rdev = rcu_dereference(conf->mirrors[i].rdev);
1560 		seq_printf(seq, "%s", rdev && test_bit(In_sync, &rdev->flags) ? "U" : "_");
1561 	}
1562 	rcu_read_unlock();
1563 	seq_printf(seq, "]");
1564 }
1565 
1566 /* check if there are enough drives for
1567  * every block to appear on atleast one.
1568  * Don't consider the device numbered 'ignore'
1569  * as we might be about to remove it.
1570  */
_enough(struct r10conf * conf,int previous,int ignore)1571 static int _enough(struct r10conf *conf, int previous, int ignore)
1572 {
1573 	int first = 0;
1574 	int has_enough = 0;
1575 	int disks, ncopies;
1576 	if (previous) {
1577 		disks = conf->prev.raid_disks;
1578 		ncopies = conf->prev.near_copies;
1579 	} else {
1580 		disks = conf->geo.raid_disks;
1581 		ncopies = conf->geo.near_copies;
1582 	}
1583 
1584 	rcu_read_lock();
1585 	do {
1586 		int n = conf->copies;
1587 		int cnt = 0;
1588 		int this = first;
1589 		while (n--) {
1590 			struct md_rdev *rdev;
1591 			if (this != ignore &&
1592 			    (rdev = rcu_dereference(conf->mirrors[this].rdev)) &&
1593 			    test_bit(In_sync, &rdev->flags))
1594 				cnt++;
1595 			this = (this+1) % disks;
1596 		}
1597 		if (cnt == 0)
1598 			goto out;
1599 		first = (first + ncopies) % disks;
1600 	} while (first != 0);
1601 	has_enough = 1;
1602 out:
1603 	rcu_read_unlock();
1604 	return has_enough;
1605 }
1606 
enough(struct r10conf * conf,int ignore)1607 static int enough(struct r10conf *conf, int ignore)
1608 {
1609 	/* when calling 'enough', both 'prev' and 'geo' must
1610 	 * be stable.
1611 	 * This is ensured if ->reconfig_mutex or ->device_lock
1612 	 * is held.
1613 	 */
1614 	return _enough(conf, 0, ignore) &&
1615 		_enough(conf, 1, ignore);
1616 }
1617 
raid10_error(struct mddev * mddev,struct md_rdev * rdev)1618 static void raid10_error(struct mddev *mddev, struct md_rdev *rdev)
1619 {
1620 	char b[BDEVNAME_SIZE];
1621 	struct r10conf *conf = mddev->private;
1622 	unsigned long flags;
1623 
1624 	/*
1625 	 * If it is not operational, then we have already marked it as dead
1626 	 * else if it is the last working disks with "fail_last_dev == false",
1627 	 * ignore the error, let the next level up know.
1628 	 * else mark the drive as failed
1629 	 */
1630 	spin_lock_irqsave(&conf->device_lock, flags);
1631 	if (test_bit(In_sync, &rdev->flags) && !mddev->fail_last_dev
1632 	    && !enough(conf, rdev->raid_disk)) {
1633 		/*
1634 		 * Don't fail the drive, just return an IO error.
1635 		 */
1636 		spin_unlock_irqrestore(&conf->device_lock, flags);
1637 		return;
1638 	}
1639 	if (test_and_clear_bit(In_sync, &rdev->flags))
1640 		mddev->degraded++;
1641 	/*
1642 	 * If recovery is running, make sure it aborts.
1643 	 */
1644 	set_bit(MD_RECOVERY_INTR, &mddev->recovery);
1645 	set_bit(Blocked, &rdev->flags);
1646 	set_bit(Faulty, &rdev->flags);
1647 	set_mask_bits(&mddev->sb_flags, 0,
1648 		      BIT(MD_SB_CHANGE_DEVS) | BIT(MD_SB_CHANGE_PENDING));
1649 	spin_unlock_irqrestore(&conf->device_lock, flags);
1650 	pr_crit("md/raid10:%s: Disk failure on %s, disabling device.\n"
1651 		"md/raid10:%s: Operation continuing on %d devices.\n",
1652 		mdname(mddev), bdevname(rdev->bdev, b),
1653 		mdname(mddev), conf->geo.raid_disks - mddev->degraded);
1654 }
1655 
print_conf(struct r10conf * conf)1656 static void print_conf(struct r10conf *conf)
1657 {
1658 	int i;
1659 	struct md_rdev *rdev;
1660 
1661 	pr_debug("RAID10 conf printout:\n");
1662 	if (!conf) {
1663 		pr_debug("(!conf)\n");
1664 		return;
1665 	}
1666 	pr_debug(" --- wd:%d rd:%d\n", conf->geo.raid_disks - conf->mddev->degraded,
1667 		 conf->geo.raid_disks);
1668 
1669 	/* This is only called with ->reconfix_mutex held, so
1670 	 * rcu protection of rdev is not needed */
1671 	for (i = 0; i < conf->geo.raid_disks; i++) {
1672 		char b[BDEVNAME_SIZE];
1673 		rdev = conf->mirrors[i].rdev;
1674 		if (rdev)
1675 			pr_debug(" disk %d, wo:%d, o:%d, dev:%s\n",
1676 				 i, !test_bit(In_sync, &rdev->flags),
1677 				 !test_bit(Faulty, &rdev->flags),
1678 				 bdevname(rdev->bdev,b));
1679 	}
1680 }
1681 
close_sync(struct r10conf * conf)1682 static void close_sync(struct r10conf *conf)
1683 {
1684 	wait_barrier(conf);
1685 	allow_barrier(conf);
1686 
1687 	mempool_exit(&conf->r10buf_pool);
1688 }
1689 
raid10_spare_active(struct mddev * mddev)1690 static int raid10_spare_active(struct mddev *mddev)
1691 {
1692 	int i;
1693 	struct r10conf *conf = mddev->private;
1694 	struct raid10_info *tmp;
1695 	int count = 0;
1696 	unsigned long flags;
1697 
1698 	/*
1699 	 * Find all non-in_sync disks within the RAID10 configuration
1700 	 * and mark them in_sync
1701 	 */
1702 	for (i = 0; i < conf->geo.raid_disks; i++) {
1703 		tmp = conf->mirrors + i;
1704 		if (tmp->replacement
1705 		    && tmp->replacement->recovery_offset == MaxSector
1706 		    && !test_bit(Faulty, &tmp->replacement->flags)
1707 		    && !test_and_set_bit(In_sync, &tmp->replacement->flags)) {
1708 			/* Replacement has just become active */
1709 			if (!tmp->rdev
1710 			    || !test_and_clear_bit(In_sync, &tmp->rdev->flags))
1711 				count++;
1712 			if (tmp->rdev) {
1713 				/* Replaced device not technically faulty,
1714 				 * but we need to be sure it gets removed
1715 				 * and never re-added.
1716 				 */
1717 				set_bit(Faulty, &tmp->rdev->flags);
1718 				sysfs_notify_dirent_safe(
1719 					tmp->rdev->sysfs_state);
1720 			}
1721 			sysfs_notify_dirent_safe(tmp->replacement->sysfs_state);
1722 		} else if (tmp->rdev
1723 			   && tmp->rdev->recovery_offset == MaxSector
1724 			   && !test_bit(Faulty, &tmp->rdev->flags)
1725 			   && !test_and_set_bit(In_sync, &tmp->rdev->flags)) {
1726 			count++;
1727 			sysfs_notify_dirent_safe(tmp->rdev->sysfs_state);
1728 		}
1729 	}
1730 	spin_lock_irqsave(&conf->device_lock, flags);
1731 	mddev->degraded -= count;
1732 	spin_unlock_irqrestore(&conf->device_lock, flags);
1733 
1734 	print_conf(conf);
1735 	return count;
1736 }
1737 
raid10_add_disk(struct mddev * mddev,struct md_rdev * rdev)1738 static int raid10_add_disk(struct mddev *mddev, struct md_rdev *rdev)
1739 {
1740 	struct r10conf *conf = mddev->private;
1741 	int err = -EEXIST;
1742 	int mirror;
1743 	int first = 0;
1744 	int last = conf->geo.raid_disks - 1;
1745 
1746 	if (mddev->recovery_cp < MaxSector)
1747 		/* only hot-add to in-sync arrays, as recovery is
1748 		 * very different from resync
1749 		 */
1750 		return -EBUSY;
1751 	if (rdev->saved_raid_disk < 0 && !_enough(conf, 1, -1))
1752 		return -EINVAL;
1753 
1754 	if (md_integrity_add_rdev(rdev, mddev))
1755 		return -ENXIO;
1756 
1757 	if (rdev->raid_disk >= 0)
1758 		first = last = rdev->raid_disk;
1759 
1760 	if (rdev->saved_raid_disk >= first &&
1761 	    rdev->saved_raid_disk < conf->geo.raid_disks &&
1762 	    conf->mirrors[rdev->saved_raid_disk].rdev == NULL)
1763 		mirror = rdev->saved_raid_disk;
1764 	else
1765 		mirror = first;
1766 	for ( ; mirror <= last ; mirror++) {
1767 		struct raid10_info *p = &conf->mirrors[mirror];
1768 		if (p->recovery_disabled == mddev->recovery_disabled)
1769 			continue;
1770 		if (p->rdev) {
1771 			if (!test_bit(WantReplacement, &p->rdev->flags) ||
1772 			    p->replacement != NULL)
1773 				continue;
1774 			clear_bit(In_sync, &rdev->flags);
1775 			set_bit(Replacement, &rdev->flags);
1776 			rdev->raid_disk = mirror;
1777 			err = 0;
1778 			if (mddev->gendisk)
1779 				disk_stack_limits(mddev->gendisk, rdev->bdev,
1780 						  rdev->data_offset << 9);
1781 			conf->fullsync = 1;
1782 			rcu_assign_pointer(p->replacement, rdev);
1783 			break;
1784 		}
1785 
1786 		if (mddev->gendisk)
1787 			disk_stack_limits(mddev->gendisk, rdev->bdev,
1788 					  rdev->data_offset << 9);
1789 
1790 		p->head_position = 0;
1791 		p->recovery_disabled = mddev->recovery_disabled - 1;
1792 		rdev->raid_disk = mirror;
1793 		err = 0;
1794 		if (rdev->saved_raid_disk != mirror)
1795 			conf->fullsync = 1;
1796 		rcu_assign_pointer(p->rdev, rdev);
1797 		break;
1798 	}
1799 	if (mddev->queue && blk_queue_discard(bdev_get_queue(rdev->bdev)))
1800 		blk_queue_flag_set(QUEUE_FLAG_DISCARD, mddev->queue);
1801 
1802 	print_conf(conf);
1803 	return err;
1804 }
1805 
raid10_remove_disk(struct mddev * mddev,struct md_rdev * rdev)1806 static int raid10_remove_disk(struct mddev *mddev, struct md_rdev *rdev)
1807 {
1808 	struct r10conf *conf = mddev->private;
1809 	int err = 0;
1810 	int number = rdev->raid_disk;
1811 	struct md_rdev **rdevp;
1812 	struct raid10_info *p;
1813 
1814 	print_conf(conf);
1815 	if (unlikely(number >= mddev->raid_disks))
1816 		return 0;
1817 	p = conf->mirrors + number;
1818 	if (rdev == p->rdev)
1819 		rdevp = &p->rdev;
1820 	else if (rdev == p->replacement)
1821 		rdevp = &p->replacement;
1822 	else
1823 		return 0;
1824 
1825 	if (test_bit(In_sync, &rdev->flags) ||
1826 	    atomic_read(&rdev->nr_pending)) {
1827 		err = -EBUSY;
1828 		goto abort;
1829 	}
1830 	/* Only remove non-faulty devices if recovery
1831 	 * is not possible.
1832 	 */
1833 	if (!test_bit(Faulty, &rdev->flags) &&
1834 	    mddev->recovery_disabled != p->recovery_disabled &&
1835 	    (!p->replacement || p->replacement == rdev) &&
1836 	    number < conf->geo.raid_disks &&
1837 	    enough(conf, -1)) {
1838 		err = -EBUSY;
1839 		goto abort;
1840 	}
1841 	*rdevp = NULL;
1842 	if (!test_bit(RemoveSynchronized, &rdev->flags)) {
1843 		synchronize_rcu();
1844 		if (atomic_read(&rdev->nr_pending)) {
1845 			/* lost the race, try later */
1846 			err = -EBUSY;
1847 			*rdevp = rdev;
1848 			goto abort;
1849 		}
1850 	}
1851 	if (p->replacement) {
1852 		/* We must have just cleared 'rdev' */
1853 		p->rdev = p->replacement;
1854 		clear_bit(Replacement, &p->replacement->flags);
1855 		smp_mb(); /* Make sure other CPUs may see both as identical
1856 			   * but will never see neither -- if they are careful.
1857 			   */
1858 		p->replacement = NULL;
1859 	}
1860 
1861 	clear_bit(WantReplacement, &rdev->flags);
1862 	err = md_integrity_register(mddev);
1863 
1864 abort:
1865 
1866 	print_conf(conf);
1867 	return err;
1868 }
1869 
__end_sync_read(struct r10bio * r10_bio,struct bio * bio,int d)1870 static void __end_sync_read(struct r10bio *r10_bio, struct bio *bio, int d)
1871 {
1872 	struct r10conf *conf = r10_bio->mddev->private;
1873 
1874 	if (!bio->bi_status)
1875 		set_bit(R10BIO_Uptodate, &r10_bio->state);
1876 	else
1877 		/* The write handler will notice the lack of
1878 		 * R10BIO_Uptodate and record any errors etc
1879 		 */
1880 		atomic_add(r10_bio->sectors,
1881 			   &conf->mirrors[d].rdev->corrected_errors);
1882 
1883 	/* for reconstruct, we always reschedule after a read.
1884 	 * for resync, only after all reads
1885 	 */
1886 	rdev_dec_pending(conf->mirrors[d].rdev, conf->mddev);
1887 	if (test_bit(R10BIO_IsRecover, &r10_bio->state) ||
1888 	    atomic_dec_and_test(&r10_bio->remaining)) {
1889 		/* we have read all the blocks,
1890 		 * do the comparison in process context in raid10d
1891 		 */
1892 		reschedule_retry(r10_bio);
1893 	}
1894 }
1895 
end_sync_read(struct bio * bio)1896 static void end_sync_read(struct bio *bio)
1897 {
1898 	struct r10bio *r10_bio = get_resync_r10bio(bio);
1899 	struct r10conf *conf = r10_bio->mddev->private;
1900 	int d = find_bio_disk(conf, r10_bio, bio, NULL, NULL);
1901 
1902 	__end_sync_read(r10_bio, bio, d);
1903 }
1904 
end_reshape_read(struct bio * bio)1905 static void end_reshape_read(struct bio *bio)
1906 {
1907 	/* reshape read bio isn't allocated from r10buf_pool */
1908 	struct r10bio *r10_bio = bio->bi_private;
1909 
1910 	__end_sync_read(r10_bio, bio, r10_bio->read_slot);
1911 }
1912 
end_sync_request(struct r10bio * r10_bio)1913 static void end_sync_request(struct r10bio *r10_bio)
1914 {
1915 	struct mddev *mddev = r10_bio->mddev;
1916 
1917 	while (atomic_dec_and_test(&r10_bio->remaining)) {
1918 		if (r10_bio->master_bio == NULL) {
1919 			/* the primary of several recovery bios */
1920 			sector_t s = r10_bio->sectors;
1921 			if (test_bit(R10BIO_MadeGood, &r10_bio->state) ||
1922 			    test_bit(R10BIO_WriteError, &r10_bio->state))
1923 				reschedule_retry(r10_bio);
1924 			else
1925 				put_buf(r10_bio);
1926 			md_done_sync(mddev, s, 1);
1927 			break;
1928 		} else {
1929 			struct r10bio *r10_bio2 = (struct r10bio *)r10_bio->master_bio;
1930 			if (test_bit(R10BIO_MadeGood, &r10_bio->state) ||
1931 			    test_bit(R10BIO_WriteError, &r10_bio->state))
1932 				reschedule_retry(r10_bio);
1933 			else
1934 				put_buf(r10_bio);
1935 			r10_bio = r10_bio2;
1936 		}
1937 	}
1938 }
1939 
end_sync_write(struct bio * bio)1940 static void end_sync_write(struct bio *bio)
1941 {
1942 	struct r10bio *r10_bio = get_resync_r10bio(bio);
1943 	struct mddev *mddev = r10_bio->mddev;
1944 	struct r10conf *conf = mddev->private;
1945 	int d;
1946 	sector_t first_bad;
1947 	int bad_sectors;
1948 	int slot;
1949 	int repl;
1950 	struct md_rdev *rdev = NULL;
1951 
1952 	d = find_bio_disk(conf, r10_bio, bio, &slot, &repl);
1953 	if (repl)
1954 		rdev = conf->mirrors[d].replacement;
1955 	else
1956 		rdev = conf->mirrors[d].rdev;
1957 
1958 	if (bio->bi_status) {
1959 		if (repl)
1960 			md_error(mddev, rdev);
1961 		else {
1962 			set_bit(WriteErrorSeen, &rdev->flags);
1963 			if (!test_and_set_bit(WantReplacement, &rdev->flags))
1964 				set_bit(MD_RECOVERY_NEEDED,
1965 					&rdev->mddev->recovery);
1966 			set_bit(R10BIO_WriteError, &r10_bio->state);
1967 		}
1968 	} else if (is_badblock(rdev,
1969 			     r10_bio->devs[slot].addr,
1970 			     r10_bio->sectors,
1971 			     &first_bad, &bad_sectors))
1972 		set_bit(R10BIO_MadeGood, &r10_bio->state);
1973 
1974 	rdev_dec_pending(rdev, mddev);
1975 
1976 	end_sync_request(r10_bio);
1977 }
1978 
1979 /*
1980  * Note: sync and recover and handled very differently for raid10
1981  * This code is for resync.
1982  * For resync, we read through virtual addresses and read all blocks.
1983  * If there is any error, we schedule a write.  The lowest numbered
1984  * drive is authoritative.
1985  * However requests come for physical address, so we need to map.
1986  * For every physical address there are raid_disks/copies virtual addresses,
1987  * which is always are least one, but is not necessarly an integer.
1988  * This means that a physical address can span multiple chunks, so we may
1989  * have to submit multiple io requests for a single sync request.
1990  */
1991 /*
1992  * We check if all blocks are in-sync and only write to blocks that
1993  * aren't in sync
1994  */
sync_request_write(struct mddev * mddev,struct r10bio * r10_bio)1995 static void sync_request_write(struct mddev *mddev, struct r10bio *r10_bio)
1996 {
1997 	struct r10conf *conf = mddev->private;
1998 	int i, first;
1999 	struct bio *tbio, *fbio;
2000 	int vcnt;
2001 	struct page **tpages, **fpages;
2002 
2003 	atomic_set(&r10_bio->remaining, 1);
2004 
2005 	/* find the first device with a block */
2006 	for (i=0; i<conf->copies; i++)
2007 		if (!r10_bio->devs[i].bio->bi_status)
2008 			break;
2009 
2010 	if (i == conf->copies)
2011 		goto done;
2012 
2013 	first = i;
2014 	fbio = r10_bio->devs[i].bio;
2015 	fbio->bi_iter.bi_size = r10_bio->sectors << 9;
2016 	fbio->bi_iter.bi_idx = 0;
2017 	fpages = get_resync_pages(fbio)->pages;
2018 
2019 	vcnt = (r10_bio->sectors + (PAGE_SIZE >> 9) - 1) >> (PAGE_SHIFT - 9);
2020 	/* now find blocks with errors */
2021 	for (i=0 ; i < conf->copies ; i++) {
2022 		int  j, d;
2023 		struct md_rdev *rdev;
2024 		struct resync_pages *rp;
2025 
2026 		tbio = r10_bio->devs[i].bio;
2027 
2028 		if (tbio->bi_end_io != end_sync_read)
2029 			continue;
2030 		if (i == first)
2031 			continue;
2032 
2033 		tpages = get_resync_pages(tbio)->pages;
2034 		d = r10_bio->devs[i].devnum;
2035 		rdev = conf->mirrors[d].rdev;
2036 		if (!r10_bio->devs[i].bio->bi_status) {
2037 			/* We know that the bi_io_vec layout is the same for
2038 			 * both 'first' and 'i', so we just compare them.
2039 			 * All vec entries are PAGE_SIZE;
2040 			 */
2041 			int sectors = r10_bio->sectors;
2042 			for (j = 0; j < vcnt; j++) {
2043 				int len = PAGE_SIZE;
2044 				if (sectors < (len / 512))
2045 					len = sectors * 512;
2046 				if (memcmp(page_address(fpages[j]),
2047 					   page_address(tpages[j]),
2048 					   len))
2049 					break;
2050 				sectors -= len/512;
2051 			}
2052 			if (j == vcnt)
2053 				continue;
2054 			atomic64_add(r10_bio->sectors, &mddev->resync_mismatches);
2055 			if (test_bit(MD_RECOVERY_CHECK, &mddev->recovery))
2056 				/* Don't fix anything. */
2057 				continue;
2058 		} else if (test_bit(FailFast, &rdev->flags)) {
2059 			/* Just give up on this device */
2060 			md_error(rdev->mddev, rdev);
2061 			continue;
2062 		}
2063 		/* Ok, we need to write this bio, either to correct an
2064 		 * inconsistency or to correct an unreadable block.
2065 		 * First we need to fixup bv_offset, bv_len and
2066 		 * bi_vecs, as the read request might have corrupted these
2067 		 */
2068 		rp = get_resync_pages(tbio);
2069 		bio_reset(tbio);
2070 
2071 		md_bio_reset_resync_pages(tbio, rp, fbio->bi_iter.bi_size);
2072 
2073 		rp->raid_bio = r10_bio;
2074 		tbio->bi_private = rp;
2075 		tbio->bi_iter.bi_sector = r10_bio->devs[i].addr;
2076 		tbio->bi_end_io = end_sync_write;
2077 		bio_set_op_attrs(tbio, REQ_OP_WRITE, 0);
2078 
2079 		bio_copy_data(tbio, fbio);
2080 
2081 		atomic_inc(&conf->mirrors[d].rdev->nr_pending);
2082 		atomic_inc(&r10_bio->remaining);
2083 		md_sync_acct(conf->mirrors[d].rdev->bdev, bio_sectors(tbio));
2084 
2085 		if (test_bit(FailFast, &conf->mirrors[d].rdev->flags))
2086 			tbio->bi_opf |= MD_FAILFAST;
2087 		tbio->bi_iter.bi_sector += conf->mirrors[d].rdev->data_offset;
2088 		bio_set_dev(tbio, conf->mirrors[d].rdev->bdev);
2089 		submit_bio_noacct(tbio);
2090 	}
2091 
2092 	/* Now write out to any replacement devices
2093 	 * that are active
2094 	 */
2095 	for (i = 0; i < conf->copies; i++) {
2096 		int d;
2097 
2098 		tbio = r10_bio->devs[i].repl_bio;
2099 		if (!tbio || !tbio->bi_end_io)
2100 			continue;
2101 		if (r10_bio->devs[i].bio->bi_end_io != end_sync_write
2102 		    && r10_bio->devs[i].bio != fbio)
2103 			bio_copy_data(tbio, fbio);
2104 		d = r10_bio->devs[i].devnum;
2105 		atomic_inc(&r10_bio->remaining);
2106 		md_sync_acct(conf->mirrors[d].replacement->bdev,
2107 			     bio_sectors(tbio));
2108 		submit_bio_noacct(tbio);
2109 	}
2110 
2111 done:
2112 	if (atomic_dec_and_test(&r10_bio->remaining)) {
2113 		md_done_sync(mddev, r10_bio->sectors, 1);
2114 		put_buf(r10_bio);
2115 	}
2116 }
2117 
2118 /*
2119  * Now for the recovery code.
2120  * Recovery happens across physical sectors.
2121  * We recover all non-is_sync drives by finding the virtual address of
2122  * each, and then choose a working drive that also has that virt address.
2123  * There is a separate r10_bio for each non-in_sync drive.
2124  * Only the first two slots are in use. The first for reading,
2125  * The second for writing.
2126  *
2127  */
fix_recovery_read_error(struct r10bio * r10_bio)2128 static void fix_recovery_read_error(struct r10bio *r10_bio)
2129 {
2130 	/* We got a read error during recovery.
2131 	 * We repeat the read in smaller page-sized sections.
2132 	 * If a read succeeds, write it to the new device or record
2133 	 * a bad block if we cannot.
2134 	 * If a read fails, record a bad block on both old and
2135 	 * new devices.
2136 	 */
2137 	struct mddev *mddev = r10_bio->mddev;
2138 	struct r10conf *conf = mddev->private;
2139 	struct bio *bio = r10_bio->devs[0].bio;
2140 	sector_t sect = 0;
2141 	int sectors = r10_bio->sectors;
2142 	int idx = 0;
2143 	int dr = r10_bio->devs[0].devnum;
2144 	int dw = r10_bio->devs[1].devnum;
2145 	struct page **pages = get_resync_pages(bio)->pages;
2146 
2147 	while (sectors) {
2148 		int s = sectors;
2149 		struct md_rdev *rdev;
2150 		sector_t addr;
2151 		int ok;
2152 
2153 		if (s > (PAGE_SIZE>>9))
2154 			s = PAGE_SIZE >> 9;
2155 
2156 		rdev = conf->mirrors[dr].rdev;
2157 		addr = r10_bio->devs[0].addr + sect,
2158 		ok = sync_page_io(rdev,
2159 				  addr,
2160 				  s << 9,
2161 				  pages[idx],
2162 				  REQ_OP_READ, 0, false);
2163 		if (ok) {
2164 			rdev = conf->mirrors[dw].rdev;
2165 			addr = r10_bio->devs[1].addr + sect;
2166 			ok = sync_page_io(rdev,
2167 					  addr,
2168 					  s << 9,
2169 					  pages[idx],
2170 					  REQ_OP_WRITE, 0, false);
2171 			if (!ok) {
2172 				set_bit(WriteErrorSeen, &rdev->flags);
2173 				if (!test_and_set_bit(WantReplacement,
2174 						      &rdev->flags))
2175 					set_bit(MD_RECOVERY_NEEDED,
2176 						&rdev->mddev->recovery);
2177 			}
2178 		}
2179 		if (!ok) {
2180 			/* We don't worry if we cannot set a bad block -
2181 			 * it really is bad so there is no loss in not
2182 			 * recording it yet
2183 			 */
2184 			rdev_set_badblocks(rdev, addr, s, 0);
2185 
2186 			if (rdev != conf->mirrors[dw].rdev) {
2187 				/* need bad block on destination too */
2188 				struct md_rdev *rdev2 = conf->mirrors[dw].rdev;
2189 				addr = r10_bio->devs[1].addr + sect;
2190 				ok = rdev_set_badblocks(rdev2, addr, s, 0);
2191 				if (!ok) {
2192 					/* just abort the recovery */
2193 					pr_notice("md/raid10:%s: recovery aborted due to read error\n",
2194 						  mdname(mddev));
2195 
2196 					conf->mirrors[dw].recovery_disabled
2197 						= mddev->recovery_disabled;
2198 					set_bit(MD_RECOVERY_INTR,
2199 						&mddev->recovery);
2200 					break;
2201 				}
2202 			}
2203 		}
2204 
2205 		sectors -= s;
2206 		sect += s;
2207 		idx++;
2208 	}
2209 }
2210 
recovery_request_write(struct mddev * mddev,struct r10bio * r10_bio)2211 static void recovery_request_write(struct mddev *mddev, struct r10bio *r10_bio)
2212 {
2213 	struct r10conf *conf = mddev->private;
2214 	int d;
2215 	struct bio *wbio = r10_bio->devs[1].bio;
2216 	struct bio *wbio2 = r10_bio->devs[1].repl_bio;
2217 
2218 	/* Need to test wbio2->bi_end_io before we call
2219 	 * submit_bio_noacct as if the former is NULL,
2220 	 * the latter is free to free wbio2.
2221 	 */
2222 	if (wbio2 && !wbio2->bi_end_io)
2223 		wbio2 = NULL;
2224 
2225 	if (!test_bit(R10BIO_Uptodate, &r10_bio->state)) {
2226 		fix_recovery_read_error(r10_bio);
2227 		if (wbio->bi_end_io)
2228 			end_sync_request(r10_bio);
2229 		if (wbio2)
2230 			end_sync_request(r10_bio);
2231 		return;
2232 	}
2233 
2234 	/*
2235 	 * share the pages with the first bio
2236 	 * and submit the write request
2237 	 */
2238 	d = r10_bio->devs[1].devnum;
2239 	if (wbio->bi_end_io) {
2240 		atomic_inc(&conf->mirrors[d].rdev->nr_pending);
2241 		md_sync_acct(conf->mirrors[d].rdev->bdev, bio_sectors(wbio));
2242 		submit_bio_noacct(wbio);
2243 	}
2244 	if (wbio2) {
2245 		atomic_inc(&conf->mirrors[d].replacement->nr_pending);
2246 		md_sync_acct(conf->mirrors[d].replacement->bdev,
2247 			     bio_sectors(wbio2));
2248 		submit_bio_noacct(wbio2);
2249 	}
2250 }
2251 
2252 /*
2253  * Used by fix_read_error() to decay the per rdev read_errors.
2254  * We halve the read error count for every hour that has elapsed
2255  * since the last recorded read error.
2256  *
2257  */
check_decay_read_errors(struct mddev * mddev,struct md_rdev * rdev)2258 static void check_decay_read_errors(struct mddev *mddev, struct md_rdev *rdev)
2259 {
2260 	long cur_time_mon;
2261 	unsigned long hours_since_last;
2262 	unsigned int read_errors = atomic_read(&rdev->read_errors);
2263 
2264 	cur_time_mon = ktime_get_seconds();
2265 
2266 	if (rdev->last_read_error == 0) {
2267 		/* first time we've seen a read error */
2268 		rdev->last_read_error = cur_time_mon;
2269 		return;
2270 	}
2271 
2272 	hours_since_last = (long)(cur_time_mon -
2273 			    rdev->last_read_error) / 3600;
2274 
2275 	rdev->last_read_error = cur_time_mon;
2276 
2277 	/*
2278 	 * if hours_since_last is > the number of bits in read_errors
2279 	 * just set read errors to 0. We do this to avoid
2280 	 * overflowing the shift of read_errors by hours_since_last.
2281 	 */
2282 	if (hours_since_last >= 8 * sizeof(read_errors))
2283 		atomic_set(&rdev->read_errors, 0);
2284 	else
2285 		atomic_set(&rdev->read_errors, read_errors >> hours_since_last);
2286 }
2287 
r10_sync_page_io(struct md_rdev * rdev,sector_t sector,int sectors,struct page * page,int rw)2288 static int r10_sync_page_io(struct md_rdev *rdev, sector_t sector,
2289 			    int sectors, struct page *page, int rw)
2290 {
2291 	sector_t first_bad;
2292 	int bad_sectors;
2293 
2294 	if (is_badblock(rdev, sector, sectors, &first_bad, &bad_sectors)
2295 	    && (rw == READ || test_bit(WriteErrorSeen, &rdev->flags)))
2296 		return -1;
2297 	if (sync_page_io(rdev, sector, sectors << 9, page, rw, 0, false))
2298 		/* success */
2299 		return 1;
2300 	if (rw == WRITE) {
2301 		set_bit(WriteErrorSeen, &rdev->flags);
2302 		if (!test_and_set_bit(WantReplacement, &rdev->flags))
2303 			set_bit(MD_RECOVERY_NEEDED,
2304 				&rdev->mddev->recovery);
2305 	}
2306 	/* need to record an error - either for the block or the device */
2307 	if (!rdev_set_badblocks(rdev, sector, sectors, 0))
2308 		md_error(rdev->mddev, rdev);
2309 	return 0;
2310 }
2311 
2312 /*
2313  * This is a kernel thread which:
2314  *
2315  *	1.	Retries failed read operations on working mirrors.
2316  *	2.	Updates the raid superblock when problems encounter.
2317  *	3.	Performs writes following reads for array synchronising.
2318  */
2319 
fix_read_error(struct r10conf * conf,struct mddev * mddev,struct r10bio * r10_bio)2320 static void fix_read_error(struct r10conf *conf, struct mddev *mddev, struct r10bio *r10_bio)
2321 {
2322 	int sect = 0; /* Offset from r10_bio->sector */
2323 	int sectors = r10_bio->sectors;
2324 	struct md_rdev *rdev;
2325 	int max_read_errors = atomic_read(&mddev->max_corr_read_errors);
2326 	int d = r10_bio->devs[r10_bio->read_slot].devnum;
2327 
2328 	/* still own a reference to this rdev, so it cannot
2329 	 * have been cleared recently.
2330 	 */
2331 	rdev = conf->mirrors[d].rdev;
2332 
2333 	if (test_bit(Faulty, &rdev->flags))
2334 		/* drive has already been failed, just ignore any
2335 		   more fix_read_error() attempts */
2336 		return;
2337 
2338 	check_decay_read_errors(mddev, rdev);
2339 	atomic_inc(&rdev->read_errors);
2340 	if (atomic_read(&rdev->read_errors) > max_read_errors) {
2341 		char b[BDEVNAME_SIZE];
2342 		bdevname(rdev->bdev, b);
2343 
2344 		pr_notice("md/raid10:%s: %s: Raid device exceeded read_error threshold [cur %d:max %d]\n",
2345 			  mdname(mddev), b,
2346 			  atomic_read(&rdev->read_errors), max_read_errors);
2347 		pr_notice("md/raid10:%s: %s: Failing raid device\n",
2348 			  mdname(mddev), b);
2349 		md_error(mddev, rdev);
2350 		r10_bio->devs[r10_bio->read_slot].bio = IO_BLOCKED;
2351 		return;
2352 	}
2353 
2354 	while(sectors) {
2355 		int s = sectors;
2356 		int sl = r10_bio->read_slot;
2357 		int success = 0;
2358 		int start;
2359 
2360 		if (s > (PAGE_SIZE>>9))
2361 			s = PAGE_SIZE >> 9;
2362 
2363 		rcu_read_lock();
2364 		do {
2365 			sector_t first_bad;
2366 			int bad_sectors;
2367 
2368 			d = r10_bio->devs[sl].devnum;
2369 			rdev = rcu_dereference(conf->mirrors[d].rdev);
2370 			if (rdev &&
2371 			    test_bit(In_sync, &rdev->flags) &&
2372 			    !test_bit(Faulty, &rdev->flags) &&
2373 			    is_badblock(rdev, r10_bio->devs[sl].addr + sect, s,
2374 					&first_bad, &bad_sectors) == 0) {
2375 				atomic_inc(&rdev->nr_pending);
2376 				rcu_read_unlock();
2377 				success = sync_page_io(rdev,
2378 						       r10_bio->devs[sl].addr +
2379 						       sect,
2380 						       s<<9,
2381 						       conf->tmppage,
2382 						       REQ_OP_READ, 0, false);
2383 				rdev_dec_pending(rdev, mddev);
2384 				rcu_read_lock();
2385 				if (success)
2386 					break;
2387 			}
2388 			sl++;
2389 			if (sl == conf->copies)
2390 				sl = 0;
2391 		} while (!success && sl != r10_bio->read_slot);
2392 		rcu_read_unlock();
2393 
2394 		if (!success) {
2395 			/* Cannot read from anywhere, just mark the block
2396 			 * as bad on the first device to discourage future
2397 			 * reads.
2398 			 */
2399 			int dn = r10_bio->devs[r10_bio->read_slot].devnum;
2400 			rdev = conf->mirrors[dn].rdev;
2401 
2402 			if (!rdev_set_badblocks(
2403 				    rdev,
2404 				    r10_bio->devs[r10_bio->read_slot].addr
2405 				    + sect,
2406 				    s, 0)) {
2407 				md_error(mddev, rdev);
2408 				r10_bio->devs[r10_bio->read_slot].bio
2409 					= IO_BLOCKED;
2410 			}
2411 			break;
2412 		}
2413 
2414 		start = sl;
2415 		/* write it back and re-read */
2416 		rcu_read_lock();
2417 		while (sl != r10_bio->read_slot) {
2418 			char b[BDEVNAME_SIZE];
2419 
2420 			if (sl==0)
2421 				sl = conf->copies;
2422 			sl--;
2423 			d = r10_bio->devs[sl].devnum;
2424 			rdev = rcu_dereference(conf->mirrors[d].rdev);
2425 			if (!rdev ||
2426 			    test_bit(Faulty, &rdev->flags) ||
2427 			    !test_bit(In_sync, &rdev->flags))
2428 				continue;
2429 
2430 			atomic_inc(&rdev->nr_pending);
2431 			rcu_read_unlock();
2432 			if (r10_sync_page_io(rdev,
2433 					     r10_bio->devs[sl].addr +
2434 					     sect,
2435 					     s, conf->tmppage, WRITE)
2436 			    == 0) {
2437 				/* Well, this device is dead */
2438 				pr_notice("md/raid10:%s: read correction write failed (%d sectors at %llu on %s)\n",
2439 					  mdname(mddev), s,
2440 					  (unsigned long long)(
2441 						  sect +
2442 						  choose_data_offset(r10_bio,
2443 								     rdev)),
2444 					  bdevname(rdev->bdev, b));
2445 				pr_notice("md/raid10:%s: %s: failing drive\n",
2446 					  mdname(mddev),
2447 					  bdevname(rdev->bdev, b));
2448 			}
2449 			rdev_dec_pending(rdev, mddev);
2450 			rcu_read_lock();
2451 		}
2452 		sl = start;
2453 		while (sl != r10_bio->read_slot) {
2454 			char b[BDEVNAME_SIZE];
2455 
2456 			if (sl==0)
2457 				sl = conf->copies;
2458 			sl--;
2459 			d = r10_bio->devs[sl].devnum;
2460 			rdev = rcu_dereference(conf->mirrors[d].rdev);
2461 			if (!rdev ||
2462 			    test_bit(Faulty, &rdev->flags) ||
2463 			    !test_bit(In_sync, &rdev->flags))
2464 				continue;
2465 
2466 			atomic_inc(&rdev->nr_pending);
2467 			rcu_read_unlock();
2468 			switch (r10_sync_page_io(rdev,
2469 					     r10_bio->devs[sl].addr +
2470 					     sect,
2471 					     s, conf->tmppage,
2472 						 READ)) {
2473 			case 0:
2474 				/* Well, this device is dead */
2475 				pr_notice("md/raid10:%s: unable to read back corrected sectors (%d sectors at %llu on %s)\n",
2476 				       mdname(mddev), s,
2477 				       (unsigned long long)(
2478 					       sect +
2479 					       choose_data_offset(r10_bio, rdev)),
2480 				       bdevname(rdev->bdev, b));
2481 				pr_notice("md/raid10:%s: %s: failing drive\n",
2482 				       mdname(mddev),
2483 				       bdevname(rdev->bdev, b));
2484 				break;
2485 			case 1:
2486 				pr_info("md/raid10:%s: read error corrected (%d sectors at %llu on %s)\n",
2487 				       mdname(mddev), s,
2488 				       (unsigned long long)(
2489 					       sect +
2490 					       choose_data_offset(r10_bio, rdev)),
2491 				       bdevname(rdev->bdev, b));
2492 				atomic_add(s, &rdev->corrected_errors);
2493 			}
2494 
2495 			rdev_dec_pending(rdev, mddev);
2496 			rcu_read_lock();
2497 		}
2498 		rcu_read_unlock();
2499 
2500 		sectors -= s;
2501 		sect += s;
2502 	}
2503 }
2504 
narrow_write_error(struct r10bio * r10_bio,int i)2505 static int narrow_write_error(struct r10bio *r10_bio, int i)
2506 {
2507 	struct bio *bio = r10_bio->master_bio;
2508 	struct mddev *mddev = r10_bio->mddev;
2509 	struct r10conf *conf = mddev->private;
2510 	struct md_rdev *rdev = conf->mirrors[r10_bio->devs[i].devnum].rdev;
2511 	/* bio has the data to be written to slot 'i' where
2512 	 * we just recently had a write error.
2513 	 * We repeatedly clone the bio and trim down to one block,
2514 	 * then try the write.  Where the write fails we record
2515 	 * a bad block.
2516 	 * It is conceivable that the bio doesn't exactly align with
2517 	 * blocks.  We must handle this.
2518 	 *
2519 	 * We currently own a reference to the rdev.
2520 	 */
2521 
2522 	int block_sectors;
2523 	sector_t sector;
2524 	int sectors;
2525 	int sect_to_write = r10_bio->sectors;
2526 	int ok = 1;
2527 
2528 	if (rdev->badblocks.shift < 0)
2529 		return 0;
2530 
2531 	block_sectors = roundup(1 << rdev->badblocks.shift,
2532 				bdev_logical_block_size(rdev->bdev) >> 9);
2533 	sector = r10_bio->sector;
2534 	sectors = ((r10_bio->sector + block_sectors)
2535 		   & ~(sector_t)(block_sectors - 1))
2536 		- sector;
2537 
2538 	while (sect_to_write) {
2539 		struct bio *wbio;
2540 		sector_t wsector;
2541 		if (sectors > sect_to_write)
2542 			sectors = sect_to_write;
2543 		/* Write at 'sector' for 'sectors' */
2544 		wbio = bio_clone_fast(bio, GFP_NOIO, &mddev->bio_set);
2545 		bio_trim(wbio, sector - bio->bi_iter.bi_sector, sectors);
2546 		wsector = r10_bio->devs[i].addr + (sector - r10_bio->sector);
2547 		wbio->bi_iter.bi_sector = wsector +
2548 				   choose_data_offset(r10_bio, rdev);
2549 		bio_set_dev(wbio, rdev->bdev);
2550 		bio_set_op_attrs(wbio, REQ_OP_WRITE, 0);
2551 
2552 		if (submit_bio_wait(wbio) < 0)
2553 			/* Failure! */
2554 			ok = rdev_set_badblocks(rdev, wsector,
2555 						sectors, 0)
2556 				&& ok;
2557 
2558 		bio_put(wbio);
2559 		sect_to_write -= sectors;
2560 		sector += sectors;
2561 		sectors = block_sectors;
2562 	}
2563 	return ok;
2564 }
2565 
handle_read_error(struct mddev * mddev,struct r10bio * r10_bio)2566 static void handle_read_error(struct mddev *mddev, struct r10bio *r10_bio)
2567 {
2568 	int slot = r10_bio->read_slot;
2569 	struct bio *bio;
2570 	struct r10conf *conf = mddev->private;
2571 	struct md_rdev *rdev = r10_bio->devs[slot].rdev;
2572 
2573 	/* we got a read error. Maybe the drive is bad.  Maybe just
2574 	 * the block and we can fix it.
2575 	 * We freeze all other IO, and try reading the block from
2576 	 * other devices.  When we find one, we re-write
2577 	 * and check it that fixes the read error.
2578 	 * This is all done synchronously while the array is
2579 	 * frozen.
2580 	 */
2581 	bio = r10_bio->devs[slot].bio;
2582 	bio_put(bio);
2583 	r10_bio->devs[slot].bio = NULL;
2584 
2585 	if (mddev->ro)
2586 		r10_bio->devs[slot].bio = IO_BLOCKED;
2587 	else if (!test_bit(FailFast, &rdev->flags)) {
2588 		freeze_array(conf, 1);
2589 		fix_read_error(conf, mddev, r10_bio);
2590 		unfreeze_array(conf);
2591 	} else
2592 		md_error(mddev, rdev);
2593 
2594 	rdev_dec_pending(rdev, mddev);
2595 	allow_barrier(conf);
2596 	r10_bio->state = 0;
2597 	raid10_read_request(mddev, r10_bio->master_bio, r10_bio);
2598 }
2599 
handle_write_completed(struct r10conf * conf,struct r10bio * r10_bio)2600 static void handle_write_completed(struct r10conf *conf, struct r10bio *r10_bio)
2601 {
2602 	/* Some sort of write request has finished and it
2603 	 * succeeded in writing where we thought there was a
2604 	 * bad block.  So forget the bad block.
2605 	 * Or possibly if failed and we need to record
2606 	 * a bad block.
2607 	 */
2608 	int m;
2609 	struct md_rdev *rdev;
2610 
2611 	if (test_bit(R10BIO_IsSync, &r10_bio->state) ||
2612 	    test_bit(R10BIO_IsRecover, &r10_bio->state)) {
2613 		for (m = 0; m < conf->copies; m++) {
2614 			int dev = r10_bio->devs[m].devnum;
2615 			rdev = conf->mirrors[dev].rdev;
2616 			if (r10_bio->devs[m].bio == NULL ||
2617 				r10_bio->devs[m].bio->bi_end_io == NULL)
2618 				continue;
2619 			if (!r10_bio->devs[m].bio->bi_status) {
2620 				rdev_clear_badblocks(
2621 					rdev,
2622 					r10_bio->devs[m].addr,
2623 					r10_bio->sectors, 0);
2624 			} else {
2625 				if (!rdev_set_badblocks(
2626 					    rdev,
2627 					    r10_bio->devs[m].addr,
2628 					    r10_bio->sectors, 0))
2629 					md_error(conf->mddev, rdev);
2630 			}
2631 			rdev = conf->mirrors[dev].replacement;
2632 			if (r10_bio->devs[m].repl_bio == NULL ||
2633 				r10_bio->devs[m].repl_bio->bi_end_io == NULL)
2634 				continue;
2635 
2636 			if (!r10_bio->devs[m].repl_bio->bi_status) {
2637 				rdev_clear_badblocks(
2638 					rdev,
2639 					r10_bio->devs[m].addr,
2640 					r10_bio->sectors, 0);
2641 			} else {
2642 				if (!rdev_set_badblocks(
2643 					    rdev,
2644 					    r10_bio->devs[m].addr,
2645 					    r10_bio->sectors, 0))
2646 					md_error(conf->mddev, rdev);
2647 			}
2648 		}
2649 		put_buf(r10_bio);
2650 	} else {
2651 		bool fail = false;
2652 		for (m = 0; m < conf->copies; m++) {
2653 			int dev = r10_bio->devs[m].devnum;
2654 			struct bio *bio = r10_bio->devs[m].bio;
2655 			rdev = conf->mirrors[dev].rdev;
2656 			if (bio == IO_MADE_GOOD) {
2657 				rdev_clear_badblocks(
2658 					rdev,
2659 					r10_bio->devs[m].addr,
2660 					r10_bio->sectors, 0);
2661 				rdev_dec_pending(rdev, conf->mddev);
2662 			} else if (bio != NULL && bio->bi_status) {
2663 				fail = true;
2664 				if (!narrow_write_error(r10_bio, m)) {
2665 					md_error(conf->mddev, rdev);
2666 					set_bit(R10BIO_Degraded,
2667 						&r10_bio->state);
2668 				}
2669 				rdev_dec_pending(rdev, conf->mddev);
2670 			}
2671 			bio = r10_bio->devs[m].repl_bio;
2672 			rdev = conf->mirrors[dev].replacement;
2673 			if (rdev && bio == IO_MADE_GOOD) {
2674 				rdev_clear_badblocks(
2675 					rdev,
2676 					r10_bio->devs[m].addr,
2677 					r10_bio->sectors, 0);
2678 				rdev_dec_pending(rdev, conf->mddev);
2679 			}
2680 		}
2681 		if (fail) {
2682 			spin_lock_irq(&conf->device_lock);
2683 			list_add(&r10_bio->retry_list, &conf->bio_end_io_list);
2684 			conf->nr_queued++;
2685 			spin_unlock_irq(&conf->device_lock);
2686 			/*
2687 			 * In case freeze_array() is waiting for condition
2688 			 * nr_pending == nr_queued + extra to be true.
2689 			 */
2690 			wake_up(&conf->wait_barrier);
2691 			md_wakeup_thread(conf->mddev->thread);
2692 		} else {
2693 			if (test_bit(R10BIO_WriteError,
2694 				     &r10_bio->state))
2695 				close_write(r10_bio);
2696 			raid_end_bio_io(r10_bio);
2697 		}
2698 	}
2699 }
2700 
raid10d(struct md_thread * thread)2701 static void raid10d(struct md_thread *thread)
2702 {
2703 	struct mddev *mddev = thread->mddev;
2704 	struct r10bio *r10_bio;
2705 	unsigned long flags;
2706 	struct r10conf *conf = mddev->private;
2707 	struct list_head *head = &conf->retry_list;
2708 	struct blk_plug plug;
2709 
2710 	md_check_recovery(mddev);
2711 
2712 	if (!list_empty_careful(&conf->bio_end_io_list) &&
2713 	    !test_bit(MD_SB_CHANGE_PENDING, &mddev->sb_flags)) {
2714 		LIST_HEAD(tmp);
2715 		spin_lock_irqsave(&conf->device_lock, flags);
2716 		if (!test_bit(MD_SB_CHANGE_PENDING, &mddev->sb_flags)) {
2717 			while (!list_empty(&conf->bio_end_io_list)) {
2718 				list_move(conf->bio_end_io_list.prev, &tmp);
2719 				conf->nr_queued--;
2720 			}
2721 		}
2722 		spin_unlock_irqrestore(&conf->device_lock, flags);
2723 		while (!list_empty(&tmp)) {
2724 			r10_bio = list_first_entry(&tmp, struct r10bio,
2725 						   retry_list);
2726 			list_del(&r10_bio->retry_list);
2727 			if (mddev->degraded)
2728 				set_bit(R10BIO_Degraded, &r10_bio->state);
2729 
2730 			if (test_bit(R10BIO_WriteError,
2731 				     &r10_bio->state))
2732 				close_write(r10_bio);
2733 			raid_end_bio_io(r10_bio);
2734 		}
2735 	}
2736 
2737 	blk_start_plug(&plug);
2738 	for (;;) {
2739 
2740 		flush_pending_writes(conf);
2741 
2742 		spin_lock_irqsave(&conf->device_lock, flags);
2743 		if (list_empty(head)) {
2744 			spin_unlock_irqrestore(&conf->device_lock, flags);
2745 			break;
2746 		}
2747 		r10_bio = list_entry(head->prev, struct r10bio, retry_list);
2748 		list_del(head->prev);
2749 		conf->nr_queued--;
2750 		spin_unlock_irqrestore(&conf->device_lock, flags);
2751 
2752 		mddev = r10_bio->mddev;
2753 		conf = mddev->private;
2754 		if (test_bit(R10BIO_MadeGood, &r10_bio->state) ||
2755 		    test_bit(R10BIO_WriteError, &r10_bio->state))
2756 			handle_write_completed(conf, r10_bio);
2757 		else if (test_bit(R10BIO_IsReshape, &r10_bio->state))
2758 			reshape_request_write(mddev, r10_bio);
2759 		else if (test_bit(R10BIO_IsSync, &r10_bio->state))
2760 			sync_request_write(mddev, r10_bio);
2761 		else if (test_bit(R10BIO_IsRecover, &r10_bio->state))
2762 			recovery_request_write(mddev, r10_bio);
2763 		else if (test_bit(R10BIO_ReadError, &r10_bio->state))
2764 			handle_read_error(mddev, r10_bio);
2765 		else
2766 			WARN_ON_ONCE(1);
2767 
2768 		cond_resched();
2769 		if (mddev->sb_flags & ~(1<<MD_SB_CHANGE_PENDING))
2770 			md_check_recovery(mddev);
2771 	}
2772 	blk_finish_plug(&plug);
2773 }
2774 
init_resync(struct r10conf * conf)2775 static int init_resync(struct r10conf *conf)
2776 {
2777 	int ret, buffs, i;
2778 
2779 	buffs = RESYNC_WINDOW / RESYNC_BLOCK_SIZE;
2780 	BUG_ON(mempool_initialized(&conf->r10buf_pool));
2781 	conf->have_replacement = 0;
2782 	for (i = 0; i < conf->geo.raid_disks; i++)
2783 		if (conf->mirrors[i].replacement)
2784 			conf->have_replacement = 1;
2785 	ret = mempool_init(&conf->r10buf_pool, buffs,
2786 			   r10buf_pool_alloc, r10buf_pool_free, conf);
2787 	if (ret)
2788 		return ret;
2789 	conf->next_resync = 0;
2790 	return 0;
2791 }
2792 
raid10_alloc_init_r10buf(struct r10conf * conf)2793 static struct r10bio *raid10_alloc_init_r10buf(struct r10conf *conf)
2794 {
2795 	struct r10bio *r10bio = mempool_alloc(&conf->r10buf_pool, GFP_NOIO);
2796 	struct rsync_pages *rp;
2797 	struct bio *bio;
2798 	int nalloc;
2799 	int i;
2800 
2801 	if (test_bit(MD_RECOVERY_SYNC, &conf->mddev->recovery) ||
2802 	    test_bit(MD_RECOVERY_RESHAPE, &conf->mddev->recovery))
2803 		nalloc = conf->copies; /* resync */
2804 	else
2805 		nalloc = 2; /* recovery */
2806 
2807 	for (i = 0; i < nalloc; i++) {
2808 		bio = r10bio->devs[i].bio;
2809 		rp = bio->bi_private;
2810 		bio_reset(bio);
2811 		bio->bi_private = rp;
2812 		bio = r10bio->devs[i].repl_bio;
2813 		if (bio) {
2814 			rp = bio->bi_private;
2815 			bio_reset(bio);
2816 			bio->bi_private = rp;
2817 		}
2818 	}
2819 	return r10bio;
2820 }
2821 
2822 /*
2823  * Set cluster_sync_high since we need other nodes to add the
2824  * range [cluster_sync_low, cluster_sync_high] to suspend list.
2825  */
raid10_set_cluster_sync_high(struct r10conf * conf)2826 static void raid10_set_cluster_sync_high(struct r10conf *conf)
2827 {
2828 	sector_t window_size;
2829 	int extra_chunk, chunks;
2830 
2831 	/*
2832 	 * First, here we define "stripe" as a unit which across
2833 	 * all member devices one time, so we get chunks by use
2834 	 * raid_disks / near_copies. Otherwise, if near_copies is
2835 	 * close to raid_disks, then resync window could increases
2836 	 * linearly with the increase of raid_disks, which means
2837 	 * we will suspend a really large IO window while it is not
2838 	 * necessary. If raid_disks is not divisible by near_copies,
2839 	 * an extra chunk is needed to ensure the whole "stripe" is
2840 	 * covered.
2841 	 */
2842 
2843 	chunks = conf->geo.raid_disks / conf->geo.near_copies;
2844 	if (conf->geo.raid_disks % conf->geo.near_copies == 0)
2845 		extra_chunk = 0;
2846 	else
2847 		extra_chunk = 1;
2848 	window_size = (chunks + extra_chunk) * conf->mddev->chunk_sectors;
2849 
2850 	/*
2851 	 * At least use a 32M window to align with raid1's resync window
2852 	 */
2853 	window_size = (CLUSTER_RESYNC_WINDOW_SECTORS > window_size) ?
2854 			CLUSTER_RESYNC_WINDOW_SECTORS : window_size;
2855 
2856 	conf->cluster_sync_high = conf->cluster_sync_low + window_size;
2857 }
2858 
2859 /*
2860  * perform a "sync" on one "block"
2861  *
2862  * We need to make sure that no normal I/O request - particularly write
2863  * requests - conflict with active sync requests.
2864  *
2865  * This is achieved by tracking pending requests and a 'barrier' concept
2866  * that can be installed to exclude normal IO requests.
2867  *
2868  * Resync and recovery are handled very differently.
2869  * We differentiate by looking at MD_RECOVERY_SYNC in mddev->recovery.
2870  *
2871  * For resync, we iterate over virtual addresses, read all copies,
2872  * and update if there are differences.  If only one copy is live,
2873  * skip it.
2874  * For recovery, we iterate over physical addresses, read a good
2875  * value for each non-in_sync drive, and over-write.
2876  *
2877  * So, for recovery we may have several outstanding complex requests for a
2878  * given address, one for each out-of-sync device.  We model this by allocating
2879  * a number of r10_bio structures, one for each out-of-sync device.
2880  * As we setup these structures, we collect all bio's together into a list
2881  * which we then process collectively to add pages, and then process again
2882  * to pass to submit_bio_noacct.
2883  *
2884  * The r10_bio structures are linked using a borrowed master_bio pointer.
2885  * This link is counted in ->remaining.  When the r10_bio that points to NULL
2886  * has its remaining count decremented to 0, the whole complex operation
2887  * is complete.
2888  *
2889  */
2890 
raid10_sync_request(struct mddev * mddev,sector_t sector_nr,int * skipped)2891 static sector_t raid10_sync_request(struct mddev *mddev, sector_t sector_nr,
2892 			     int *skipped)
2893 {
2894 	struct r10conf *conf = mddev->private;
2895 	struct r10bio *r10_bio;
2896 	struct bio *biolist = NULL, *bio;
2897 	sector_t max_sector, nr_sectors;
2898 	int i;
2899 	int max_sync;
2900 	sector_t sync_blocks;
2901 	sector_t sectors_skipped = 0;
2902 	int chunks_skipped = 0;
2903 	sector_t chunk_mask = conf->geo.chunk_mask;
2904 	int page_idx = 0;
2905 
2906 	/*
2907 	 * Allow skipping a full rebuild for incremental assembly
2908 	 * of a clean array, like RAID1 does.
2909 	 */
2910 	if (mddev->bitmap == NULL &&
2911 	    mddev->recovery_cp == MaxSector &&
2912 	    mddev->reshape_position == MaxSector &&
2913 	    !test_bit(MD_RECOVERY_SYNC, &mddev->recovery) &&
2914 	    !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery) &&
2915 	    !test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery) &&
2916 	    conf->fullsync == 0) {
2917 		*skipped = 1;
2918 		return mddev->dev_sectors - sector_nr;
2919 	}
2920 
2921 	if (!mempool_initialized(&conf->r10buf_pool))
2922 		if (init_resync(conf))
2923 			return 0;
2924 
2925  skipped:
2926 	max_sector = mddev->dev_sectors;
2927 	if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery) ||
2928 	    test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery))
2929 		max_sector = mddev->resync_max_sectors;
2930 	if (sector_nr >= max_sector) {
2931 		conf->cluster_sync_low = 0;
2932 		conf->cluster_sync_high = 0;
2933 
2934 		/* If we aborted, we need to abort the
2935 		 * sync on the 'current' bitmap chucks (there can
2936 		 * be several when recovering multiple devices).
2937 		 * as we may have started syncing it but not finished.
2938 		 * We can find the current address in
2939 		 * mddev->curr_resync, but for recovery,
2940 		 * we need to convert that to several
2941 		 * virtual addresses.
2942 		 */
2943 		if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery)) {
2944 			end_reshape(conf);
2945 			close_sync(conf);
2946 			return 0;
2947 		}
2948 
2949 		if (mddev->curr_resync < max_sector) { /* aborted */
2950 			if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery))
2951 				md_bitmap_end_sync(mddev->bitmap, mddev->curr_resync,
2952 						   &sync_blocks, 1);
2953 			else for (i = 0; i < conf->geo.raid_disks; i++) {
2954 				sector_t sect =
2955 					raid10_find_virt(conf, mddev->curr_resync, i);
2956 				md_bitmap_end_sync(mddev->bitmap, sect,
2957 						   &sync_blocks, 1);
2958 			}
2959 		} else {
2960 			/* completed sync */
2961 			if ((!mddev->bitmap || conf->fullsync)
2962 			    && conf->have_replacement
2963 			    && test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) {
2964 				/* Completed a full sync so the replacements
2965 				 * are now fully recovered.
2966 				 */
2967 				rcu_read_lock();
2968 				for (i = 0; i < conf->geo.raid_disks; i++) {
2969 					struct md_rdev *rdev =
2970 						rcu_dereference(conf->mirrors[i].replacement);
2971 					if (rdev)
2972 						rdev->recovery_offset = MaxSector;
2973 				}
2974 				rcu_read_unlock();
2975 			}
2976 			conf->fullsync = 0;
2977 		}
2978 		md_bitmap_close_sync(mddev->bitmap);
2979 		close_sync(conf);
2980 		*skipped = 1;
2981 		return sectors_skipped;
2982 	}
2983 
2984 	if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery))
2985 		return reshape_request(mddev, sector_nr, skipped);
2986 
2987 	if (chunks_skipped >= conf->geo.raid_disks) {
2988 		/* if there has been nothing to do on any drive,
2989 		 * then there is nothing to do at all..
2990 		 */
2991 		*skipped = 1;
2992 		return (max_sector - sector_nr) + sectors_skipped;
2993 	}
2994 
2995 	if (max_sector > mddev->resync_max)
2996 		max_sector = mddev->resync_max; /* Don't do IO beyond here */
2997 
2998 	/* make sure whole request will fit in a chunk - if chunks
2999 	 * are meaningful
3000 	 */
3001 	if (conf->geo.near_copies < conf->geo.raid_disks &&
3002 	    max_sector > (sector_nr | chunk_mask))
3003 		max_sector = (sector_nr | chunk_mask) + 1;
3004 
3005 	/*
3006 	 * If there is non-resync activity waiting for a turn, then let it
3007 	 * though before starting on this new sync request.
3008 	 */
3009 	if (conf->nr_waiting)
3010 		schedule_timeout_uninterruptible(1);
3011 
3012 	/* Again, very different code for resync and recovery.
3013 	 * Both must result in an r10bio with a list of bios that
3014 	 * have bi_end_io, bi_sector, bi_disk set,
3015 	 * and bi_private set to the r10bio.
3016 	 * For recovery, we may actually create several r10bios
3017 	 * with 2 bios in each, that correspond to the bios in the main one.
3018 	 * In this case, the subordinate r10bios link back through a
3019 	 * borrowed master_bio pointer, and the counter in the master
3020 	 * includes a ref from each subordinate.
3021 	 */
3022 	/* First, we decide what to do and set ->bi_end_io
3023 	 * To end_sync_read if we want to read, and
3024 	 * end_sync_write if we will want to write.
3025 	 */
3026 
3027 	max_sync = RESYNC_PAGES << (PAGE_SHIFT-9);
3028 	if (!test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) {
3029 		/* recovery... the complicated one */
3030 		int j;
3031 		r10_bio = NULL;
3032 
3033 		for (i = 0 ; i < conf->geo.raid_disks; i++) {
3034 			int still_degraded;
3035 			struct r10bio *rb2;
3036 			sector_t sect;
3037 			int must_sync;
3038 			int any_working;
3039 			int need_recover = 0;
3040 			int need_replace = 0;
3041 			struct raid10_info *mirror = &conf->mirrors[i];
3042 			struct md_rdev *mrdev, *mreplace;
3043 
3044 			rcu_read_lock();
3045 			mrdev = rcu_dereference(mirror->rdev);
3046 			mreplace = rcu_dereference(mirror->replacement);
3047 
3048 			if (mrdev != NULL &&
3049 			    !test_bit(Faulty, &mrdev->flags) &&
3050 			    !test_bit(In_sync, &mrdev->flags))
3051 				need_recover = 1;
3052 			if (mreplace != NULL &&
3053 			    !test_bit(Faulty, &mreplace->flags))
3054 				need_replace = 1;
3055 
3056 			if (!need_recover && !need_replace) {
3057 				rcu_read_unlock();
3058 				continue;
3059 			}
3060 
3061 			still_degraded = 0;
3062 			/* want to reconstruct this device */
3063 			rb2 = r10_bio;
3064 			sect = raid10_find_virt(conf, sector_nr, i);
3065 			if (sect >= mddev->resync_max_sectors) {
3066 				/* last stripe is not complete - don't
3067 				 * try to recover this sector.
3068 				 */
3069 				rcu_read_unlock();
3070 				continue;
3071 			}
3072 			if (mreplace && test_bit(Faulty, &mreplace->flags))
3073 				mreplace = NULL;
3074 			/* Unless we are doing a full sync, or a replacement
3075 			 * we only need to recover the block if it is set in
3076 			 * the bitmap
3077 			 */
3078 			must_sync = md_bitmap_start_sync(mddev->bitmap, sect,
3079 							 &sync_blocks, 1);
3080 			if (sync_blocks < max_sync)
3081 				max_sync = sync_blocks;
3082 			if (!must_sync &&
3083 			    mreplace == NULL &&
3084 			    !conf->fullsync) {
3085 				/* yep, skip the sync_blocks here, but don't assume
3086 				 * that there will never be anything to do here
3087 				 */
3088 				chunks_skipped = -1;
3089 				rcu_read_unlock();
3090 				continue;
3091 			}
3092 			atomic_inc(&mrdev->nr_pending);
3093 			if (mreplace)
3094 				atomic_inc(&mreplace->nr_pending);
3095 			rcu_read_unlock();
3096 
3097 			r10_bio = raid10_alloc_init_r10buf(conf);
3098 			r10_bio->state = 0;
3099 			raise_barrier(conf, rb2 != NULL);
3100 			atomic_set(&r10_bio->remaining, 0);
3101 
3102 			r10_bio->master_bio = (struct bio*)rb2;
3103 			if (rb2)
3104 				atomic_inc(&rb2->remaining);
3105 			r10_bio->mddev = mddev;
3106 			set_bit(R10BIO_IsRecover, &r10_bio->state);
3107 			r10_bio->sector = sect;
3108 
3109 			raid10_find_phys(conf, r10_bio);
3110 
3111 			/* Need to check if the array will still be
3112 			 * degraded
3113 			 */
3114 			rcu_read_lock();
3115 			for (j = 0; j < conf->geo.raid_disks; j++) {
3116 				struct md_rdev *rdev = rcu_dereference(
3117 					conf->mirrors[j].rdev);
3118 				if (rdev == NULL || test_bit(Faulty, &rdev->flags)) {
3119 					still_degraded = 1;
3120 					break;
3121 				}
3122 			}
3123 
3124 			must_sync = md_bitmap_start_sync(mddev->bitmap, sect,
3125 							 &sync_blocks, still_degraded);
3126 
3127 			any_working = 0;
3128 			for (j=0; j<conf->copies;j++) {
3129 				int k;
3130 				int d = r10_bio->devs[j].devnum;
3131 				sector_t from_addr, to_addr;
3132 				struct md_rdev *rdev =
3133 					rcu_dereference(conf->mirrors[d].rdev);
3134 				sector_t sector, first_bad;
3135 				int bad_sectors;
3136 				if (!rdev ||
3137 				    !test_bit(In_sync, &rdev->flags))
3138 					continue;
3139 				/* This is where we read from */
3140 				any_working = 1;
3141 				sector = r10_bio->devs[j].addr;
3142 
3143 				if (is_badblock(rdev, sector, max_sync,
3144 						&first_bad, &bad_sectors)) {
3145 					if (first_bad > sector)
3146 						max_sync = first_bad - sector;
3147 					else {
3148 						bad_sectors -= (sector
3149 								- first_bad);
3150 						if (max_sync > bad_sectors)
3151 							max_sync = bad_sectors;
3152 						continue;
3153 					}
3154 				}
3155 				bio = r10_bio->devs[0].bio;
3156 				bio->bi_next = biolist;
3157 				biolist = bio;
3158 				bio->bi_end_io = end_sync_read;
3159 				bio_set_op_attrs(bio, REQ_OP_READ, 0);
3160 				if (test_bit(FailFast, &rdev->flags))
3161 					bio->bi_opf |= MD_FAILFAST;
3162 				from_addr = r10_bio->devs[j].addr;
3163 				bio->bi_iter.bi_sector = from_addr +
3164 					rdev->data_offset;
3165 				bio_set_dev(bio, rdev->bdev);
3166 				atomic_inc(&rdev->nr_pending);
3167 				/* and we write to 'i' (if not in_sync) */
3168 
3169 				for (k=0; k<conf->copies; k++)
3170 					if (r10_bio->devs[k].devnum == i)
3171 						break;
3172 				BUG_ON(k == conf->copies);
3173 				to_addr = r10_bio->devs[k].addr;
3174 				r10_bio->devs[0].devnum = d;
3175 				r10_bio->devs[0].addr = from_addr;
3176 				r10_bio->devs[1].devnum = i;
3177 				r10_bio->devs[1].addr = to_addr;
3178 
3179 				if (need_recover) {
3180 					bio = r10_bio->devs[1].bio;
3181 					bio->bi_next = biolist;
3182 					biolist = bio;
3183 					bio->bi_end_io = end_sync_write;
3184 					bio_set_op_attrs(bio, REQ_OP_WRITE, 0);
3185 					bio->bi_iter.bi_sector = to_addr
3186 						+ mrdev->data_offset;
3187 					bio_set_dev(bio, mrdev->bdev);
3188 					atomic_inc(&r10_bio->remaining);
3189 				} else
3190 					r10_bio->devs[1].bio->bi_end_io = NULL;
3191 
3192 				/* and maybe write to replacement */
3193 				bio = r10_bio->devs[1].repl_bio;
3194 				if (bio)
3195 					bio->bi_end_io = NULL;
3196 				/* Note: if need_replace, then bio
3197 				 * cannot be NULL as r10buf_pool_alloc will
3198 				 * have allocated it.
3199 				 */
3200 				if (!need_replace)
3201 					break;
3202 				bio->bi_next = biolist;
3203 				biolist = bio;
3204 				bio->bi_end_io = end_sync_write;
3205 				bio_set_op_attrs(bio, REQ_OP_WRITE, 0);
3206 				bio->bi_iter.bi_sector = to_addr +
3207 					mreplace->data_offset;
3208 				bio_set_dev(bio, mreplace->bdev);
3209 				atomic_inc(&r10_bio->remaining);
3210 				break;
3211 			}
3212 			rcu_read_unlock();
3213 			if (j == conf->copies) {
3214 				/* Cannot recover, so abort the recovery or
3215 				 * record a bad block */
3216 				if (any_working) {
3217 					/* problem is that there are bad blocks
3218 					 * on other device(s)
3219 					 */
3220 					int k;
3221 					for (k = 0; k < conf->copies; k++)
3222 						if (r10_bio->devs[k].devnum == i)
3223 							break;
3224 					if (!test_bit(In_sync,
3225 						      &mrdev->flags)
3226 					    && !rdev_set_badblocks(
3227 						    mrdev,
3228 						    r10_bio->devs[k].addr,
3229 						    max_sync, 0))
3230 						any_working = 0;
3231 					if (mreplace &&
3232 					    !rdev_set_badblocks(
3233 						    mreplace,
3234 						    r10_bio->devs[k].addr,
3235 						    max_sync, 0))
3236 						any_working = 0;
3237 				}
3238 				if (!any_working)  {
3239 					if (!test_and_set_bit(MD_RECOVERY_INTR,
3240 							      &mddev->recovery))
3241 						pr_warn("md/raid10:%s: insufficient working devices for recovery.\n",
3242 						       mdname(mddev));
3243 					mirror->recovery_disabled
3244 						= mddev->recovery_disabled;
3245 				}
3246 				put_buf(r10_bio);
3247 				if (rb2)
3248 					atomic_dec(&rb2->remaining);
3249 				r10_bio = rb2;
3250 				rdev_dec_pending(mrdev, mddev);
3251 				if (mreplace)
3252 					rdev_dec_pending(mreplace, mddev);
3253 				break;
3254 			}
3255 			rdev_dec_pending(mrdev, mddev);
3256 			if (mreplace)
3257 				rdev_dec_pending(mreplace, mddev);
3258 			if (r10_bio->devs[0].bio->bi_opf & MD_FAILFAST) {
3259 				/* Only want this if there is elsewhere to
3260 				 * read from. 'j' is currently the first
3261 				 * readable copy.
3262 				 */
3263 				int targets = 1;
3264 				for (; j < conf->copies; j++) {
3265 					int d = r10_bio->devs[j].devnum;
3266 					if (conf->mirrors[d].rdev &&
3267 					    test_bit(In_sync,
3268 						      &conf->mirrors[d].rdev->flags))
3269 						targets++;
3270 				}
3271 				if (targets == 1)
3272 					r10_bio->devs[0].bio->bi_opf
3273 						&= ~MD_FAILFAST;
3274 			}
3275 		}
3276 		if (biolist == NULL) {
3277 			while (r10_bio) {
3278 				struct r10bio *rb2 = r10_bio;
3279 				r10_bio = (struct r10bio*) rb2->master_bio;
3280 				rb2->master_bio = NULL;
3281 				put_buf(rb2);
3282 			}
3283 			goto giveup;
3284 		}
3285 	} else {
3286 		/* resync. Schedule a read for every block at this virt offset */
3287 		int count = 0;
3288 
3289 		/*
3290 		 * Since curr_resync_completed could probably not update in
3291 		 * time, and we will set cluster_sync_low based on it.
3292 		 * Let's check against "sector_nr + 2 * RESYNC_SECTORS" for
3293 		 * safety reason, which ensures curr_resync_completed is
3294 		 * updated in bitmap_cond_end_sync.
3295 		 */
3296 		md_bitmap_cond_end_sync(mddev->bitmap, sector_nr,
3297 					mddev_is_clustered(mddev) &&
3298 					(sector_nr + 2 * RESYNC_SECTORS > conf->cluster_sync_high));
3299 
3300 		if (!md_bitmap_start_sync(mddev->bitmap, sector_nr,
3301 					  &sync_blocks, mddev->degraded) &&
3302 		    !conf->fullsync && !test_bit(MD_RECOVERY_REQUESTED,
3303 						 &mddev->recovery)) {
3304 			/* We can skip this block */
3305 			*skipped = 1;
3306 			return sync_blocks + sectors_skipped;
3307 		}
3308 		if (sync_blocks < max_sync)
3309 			max_sync = sync_blocks;
3310 		r10_bio = raid10_alloc_init_r10buf(conf);
3311 		r10_bio->state = 0;
3312 
3313 		r10_bio->mddev = mddev;
3314 		atomic_set(&r10_bio->remaining, 0);
3315 		raise_barrier(conf, 0);
3316 		conf->next_resync = sector_nr;
3317 
3318 		r10_bio->master_bio = NULL;
3319 		r10_bio->sector = sector_nr;
3320 		set_bit(R10BIO_IsSync, &r10_bio->state);
3321 		raid10_find_phys(conf, r10_bio);
3322 		r10_bio->sectors = (sector_nr | chunk_mask) - sector_nr + 1;
3323 
3324 		for (i = 0; i < conf->copies; i++) {
3325 			int d = r10_bio->devs[i].devnum;
3326 			sector_t first_bad, sector;
3327 			int bad_sectors;
3328 			struct md_rdev *rdev;
3329 
3330 			if (r10_bio->devs[i].repl_bio)
3331 				r10_bio->devs[i].repl_bio->bi_end_io = NULL;
3332 
3333 			bio = r10_bio->devs[i].bio;
3334 			bio->bi_status = BLK_STS_IOERR;
3335 			rcu_read_lock();
3336 			rdev = rcu_dereference(conf->mirrors[d].rdev);
3337 			if (rdev == NULL || test_bit(Faulty, &rdev->flags)) {
3338 				rcu_read_unlock();
3339 				continue;
3340 			}
3341 			sector = r10_bio->devs[i].addr;
3342 			if (is_badblock(rdev, sector, max_sync,
3343 					&first_bad, &bad_sectors)) {
3344 				if (first_bad > sector)
3345 					max_sync = first_bad - sector;
3346 				else {
3347 					bad_sectors -= (sector - first_bad);
3348 					if (max_sync > bad_sectors)
3349 						max_sync = bad_sectors;
3350 					rcu_read_unlock();
3351 					continue;
3352 				}
3353 			}
3354 			atomic_inc(&rdev->nr_pending);
3355 			atomic_inc(&r10_bio->remaining);
3356 			bio->bi_next = biolist;
3357 			biolist = bio;
3358 			bio->bi_end_io = end_sync_read;
3359 			bio_set_op_attrs(bio, REQ_OP_READ, 0);
3360 			if (test_bit(FailFast, &rdev->flags))
3361 				bio->bi_opf |= MD_FAILFAST;
3362 			bio->bi_iter.bi_sector = sector + rdev->data_offset;
3363 			bio_set_dev(bio, rdev->bdev);
3364 			count++;
3365 
3366 			rdev = rcu_dereference(conf->mirrors[d].replacement);
3367 			if (rdev == NULL || test_bit(Faulty, &rdev->flags)) {
3368 				rcu_read_unlock();
3369 				continue;
3370 			}
3371 			atomic_inc(&rdev->nr_pending);
3372 
3373 			/* Need to set up for writing to the replacement */
3374 			bio = r10_bio->devs[i].repl_bio;
3375 			bio->bi_status = BLK_STS_IOERR;
3376 
3377 			sector = r10_bio->devs[i].addr;
3378 			bio->bi_next = biolist;
3379 			biolist = bio;
3380 			bio->bi_end_io = end_sync_write;
3381 			bio_set_op_attrs(bio, REQ_OP_WRITE, 0);
3382 			if (test_bit(FailFast, &rdev->flags))
3383 				bio->bi_opf |= MD_FAILFAST;
3384 			bio->bi_iter.bi_sector = sector + rdev->data_offset;
3385 			bio_set_dev(bio, rdev->bdev);
3386 			count++;
3387 			rcu_read_unlock();
3388 		}
3389 
3390 		if (count < 2) {
3391 			for (i=0; i<conf->copies; i++) {
3392 				int d = r10_bio->devs[i].devnum;
3393 				if (r10_bio->devs[i].bio->bi_end_io)
3394 					rdev_dec_pending(conf->mirrors[d].rdev,
3395 							 mddev);
3396 				if (r10_bio->devs[i].repl_bio &&
3397 				    r10_bio->devs[i].repl_bio->bi_end_io)
3398 					rdev_dec_pending(
3399 						conf->mirrors[d].replacement,
3400 						mddev);
3401 			}
3402 			put_buf(r10_bio);
3403 			biolist = NULL;
3404 			goto giveup;
3405 		}
3406 	}
3407 
3408 	nr_sectors = 0;
3409 	if (sector_nr + max_sync < max_sector)
3410 		max_sector = sector_nr + max_sync;
3411 	do {
3412 		struct page *page;
3413 		int len = PAGE_SIZE;
3414 		if (sector_nr + (len>>9) > max_sector)
3415 			len = (max_sector - sector_nr) << 9;
3416 		if (len == 0)
3417 			break;
3418 		for (bio= biolist ; bio ; bio=bio->bi_next) {
3419 			struct resync_pages *rp = get_resync_pages(bio);
3420 			page = resync_fetch_page(rp, page_idx);
3421 			/*
3422 			 * won't fail because the vec table is big enough
3423 			 * to hold all these pages
3424 			 */
3425 			bio_add_page(bio, page, len, 0);
3426 		}
3427 		nr_sectors += len>>9;
3428 		sector_nr += len>>9;
3429 	} while (++page_idx < RESYNC_PAGES);
3430 	r10_bio->sectors = nr_sectors;
3431 
3432 	if (mddev_is_clustered(mddev) &&
3433 	    test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) {
3434 		/* It is resync not recovery */
3435 		if (conf->cluster_sync_high < sector_nr + nr_sectors) {
3436 			conf->cluster_sync_low = mddev->curr_resync_completed;
3437 			raid10_set_cluster_sync_high(conf);
3438 			/* Send resync message */
3439 			md_cluster_ops->resync_info_update(mddev,
3440 						conf->cluster_sync_low,
3441 						conf->cluster_sync_high);
3442 		}
3443 	} else if (mddev_is_clustered(mddev)) {
3444 		/* This is recovery not resync */
3445 		sector_t sect_va1, sect_va2;
3446 		bool broadcast_msg = false;
3447 
3448 		for (i = 0; i < conf->geo.raid_disks; i++) {
3449 			/*
3450 			 * sector_nr is a device address for recovery, so we
3451 			 * need translate it to array address before compare
3452 			 * with cluster_sync_high.
3453 			 */
3454 			sect_va1 = raid10_find_virt(conf, sector_nr, i);
3455 
3456 			if (conf->cluster_sync_high < sect_va1 + nr_sectors) {
3457 				broadcast_msg = true;
3458 				/*
3459 				 * curr_resync_completed is similar as
3460 				 * sector_nr, so make the translation too.
3461 				 */
3462 				sect_va2 = raid10_find_virt(conf,
3463 					mddev->curr_resync_completed, i);
3464 
3465 				if (conf->cluster_sync_low == 0 ||
3466 				    conf->cluster_sync_low > sect_va2)
3467 					conf->cluster_sync_low = sect_va2;
3468 			}
3469 		}
3470 		if (broadcast_msg) {
3471 			raid10_set_cluster_sync_high(conf);
3472 			md_cluster_ops->resync_info_update(mddev,
3473 						conf->cluster_sync_low,
3474 						conf->cluster_sync_high);
3475 		}
3476 	}
3477 
3478 	while (biolist) {
3479 		bio = biolist;
3480 		biolist = biolist->bi_next;
3481 
3482 		bio->bi_next = NULL;
3483 		r10_bio = get_resync_r10bio(bio);
3484 		r10_bio->sectors = nr_sectors;
3485 
3486 		if (bio->bi_end_io == end_sync_read) {
3487 			md_sync_acct_bio(bio, nr_sectors);
3488 			bio->bi_status = 0;
3489 			submit_bio_noacct(bio);
3490 		}
3491 	}
3492 
3493 	if (sectors_skipped)
3494 		/* pretend they weren't skipped, it makes
3495 		 * no important difference in this case
3496 		 */
3497 		md_done_sync(mddev, sectors_skipped, 1);
3498 
3499 	return sectors_skipped + nr_sectors;
3500  giveup:
3501 	/* There is nowhere to write, so all non-sync
3502 	 * drives must be failed or in resync, all drives
3503 	 * have a bad block, so try the next chunk...
3504 	 */
3505 	if (sector_nr + max_sync < max_sector)
3506 		max_sector = sector_nr + max_sync;
3507 
3508 	sectors_skipped += (max_sector - sector_nr);
3509 	chunks_skipped ++;
3510 	sector_nr = max_sector;
3511 	goto skipped;
3512 }
3513 
3514 static sector_t
raid10_size(struct mddev * mddev,sector_t sectors,int raid_disks)3515 raid10_size(struct mddev *mddev, sector_t sectors, int raid_disks)
3516 {
3517 	sector_t size;
3518 	struct r10conf *conf = mddev->private;
3519 
3520 	if (!raid_disks)
3521 		raid_disks = min(conf->geo.raid_disks,
3522 				 conf->prev.raid_disks);
3523 	if (!sectors)
3524 		sectors = conf->dev_sectors;
3525 
3526 	size = sectors >> conf->geo.chunk_shift;
3527 	sector_div(size, conf->geo.far_copies);
3528 	size = size * raid_disks;
3529 	sector_div(size, conf->geo.near_copies);
3530 
3531 	return size << conf->geo.chunk_shift;
3532 }
3533 
calc_sectors(struct r10conf * conf,sector_t size)3534 static void calc_sectors(struct r10conf *conf, sector_t size)
3535 {
3536 	/* Calculate the number of sectors-per-device that will
3537 	 * actually be used, and set conf->dev_sectors and
3538 	 * conf->stride
3539 	 */
3540 
3541 	size = size >> conf->geo.chunk_shift;
3542 	sector_div(size, conf->geo.far_copies);
3543 	size = size * conf->geo.raid_disks;
3544 	sector_div(size, conf->geo.near_copies);
3545 	/* 'size' is now the number of chunks in the array */
3546 	/* calculate "used chunks per device" */
3547 	size = size * conf->copies;
3548 
3549 	/* We need to round up when dividing by raid_disks to
3550 	 * get the stride size.
3551 	 */
3552 	size = DIV_ROUND_UP_SECTOR_T(size, conf->geo.raid_disks);
3553 
3554 	conf->dev_sectors = size << conf->geo.chunk_shift;
3555 
3556 	if (conf->geo.far_offset)
3557 		conf->geo.stride = 1 << conf->geo.chunk_shift;
3558 	else {
3559 		sector_div(size, conf->geo.far_copies);
3560 		conf->geo.stride = size << conf->geo.chunk_shift;
3561 	}
3562 }
3563 
3564 enum geo_type {geo_new, geo_old, geo_start};
setup_geo(struct geom * geo,struct mddev * mddev,enum geo_type new)3565 static int setup_geo(struct geom *geo, struct mddev *mddev, enum geo_type new)
3566 {
3567 	int nc, fc, fo;
3568 	int layout, chunk, disks;
3569 	switch (new) {
3570 	case geo_old:
3571 		layout = mddev->layout;
3572 		chunk = mddev->chunk_sectors;
3573 		disks = mddev->raid_disks - mddev->delta_disks;
3574 		break;
3575 	case geo_new:
3576 		layout = mddev->new_layout;
3577 		chunk = mddev->new_chunk_sectors;
3578 		disks = mddev->raid_disks;
3579 		break;
3580 	default: /* avoid 'may be unused' warnings */
3581 	case geo_start: /* new when starting reshape - raid_disks not
3582 			 * updated yet. */
3583 		layout = mddev->new_layout;
3584 		chunk = mddev->new_chunk_sectors;
3585 		disks = mddev->raid_disks + mddev->delta_disks;
3586 		break;
3587 	}
3588 	if (layout >> 19)
3589 		return -1;
3590 	if (chunk < (PAGE_SIZE >> 9) ||
3591 	    !is_power_of_2(chunk))
3592 		return -2;
3593 	nc = layout & 255;
3594 	fc = (layout >> 8) & 255;
3595 	fo = layout & (1<<16);
3596 	geo->raid_disks = disks;
3597 	geo->near_copies = nc;
3598 	geo->far_copies = fc;
3599 	geo->far_offset = fo;
3600 	switch (layout >> 17) {
3601 	case 0:	/* original layout.  simple but not always optimal */
3602 		geo->far_set_size = disks;
3603 		break;
3604 	case 1: /* "improved" layout which was buggy.  Hopefully no-one is
3605 		 * actually using this, but leave code here just in case.*/
3606 		geo->far_set_size = disks/fc;
3607 		WARN(geo->far_set_size < fc,
3608 		     "This RAID10 layout does not provide data safety - please backup and create new array\n");
3609 		break;
3610 	case 2: /* "improved" layout fixed to match documentation */
3611 		geo->far_set_size = fc * nc;
3612 		break;
3613 	default: /* Not a valid layout */
3614 		return -1;
3615 	}
3616 	geo->chunk_mask = chunk - 1;
3617 	geo->chunk_shift = ffz(~chunk);
3618 	return nc*fc;
3619 }
3620 
raid10_free_conf(struct r10conf * conf)3621 static void raid10_free_conf(struct r10conf *conf)
3622 {
3623 	if (!conf)
3624 		return;
3625 
3626 	mempool_exit(&conf->r10bio_pool);
3627 	kfree(conf->mirrors);
3628 	kfree(conf->mirrors_old);
3629 	kfree(conf->mirrors_new);
3630 	safe_put_page(conf->tmppage);
3631 	bioset_exit(&conf->bio_split);
3632 	kfree(conf);
3633 }
3634 
setup_conf(struct mddev * mddev)3635 static struct r10conf *setup_conf(struct mddev *mddev)
3636 {
3637 	struct r10conf *conf = NULL;
3638 	int err = -EINVAL;
3639 	struct geom geo;
3640 	int copies;
3641 
3642 	copies = setup_geo(&geo, mddev, geo_new);
3643 
3644 	if (copies == -2) {
3645 		pr_warn("md/raid10:%s: chunk size must be at least PAGE_SIZE(%ld) and be a power of 2.\n",
3646 			mdname(mddev), PAGE_SIZE);
3647 		goto out;
3648 	}
3649 
3650 	if (copies < 2 || copies > mddev->raid_disks) {
3651 		pr_warn("md/raid10:%s: unsupported raid10 layout: 0x%8x\n",
3652 			mdname(mddev), mddev->new_layout);
3653 		goto out;
3654 	}
3655 
3656 	err = -ENOMEM;
3657 	conf = kzalloc(sizeof(struct r10conf), GFP_KERNEL);
3658 	if (!conf)
3659 		goto out;
3660 
3661 	/* FIXME calc properly */
3662 	conf->mirrors = kcalloc(mddev->raid_disks + max(0, -mddev->delta_disks),
3663 				sizeof(struct raid10_info),
3664 				GFP_KERNEL);
3665 	if (!conf->mirrors)
3666 		goto out;
3667 
3668 	conf->tmppage = alloc_page(GFP_KERNEL);
3669 	if (!conf->tmppage)
3670 		goto out;
3671 
3672 	conf->geo = geo;
3673 	conf->copies = copies;
3674 	err = mempool_init(&conf->r10bio_pool, NR_RAID_BIOS, r10bio_pool_alloc,
3675 			   rbio_pool_free, conf);
3676 	if (err)
3677 		goto out;
3678 
3679 	err = bioset_init(&conf->bio_split, BIO_POOL_SIZE, 0, 0);
3680 	if (err)
3681 		goto out;
3682 
3683 	calc_sectors(conf, mddev->dev_sectors);
3684 	if (mddev->reshape_position == MaxSector) {
3685 		conf->prev = conf->geo;
3686 		conf->reshape_progress = MaxSector;
3687 	} else {
3688 		if (setup_geo(&conf->prev, mddev, geo_old) != conf->copies) {
3689 			err = -EINVAL;
3690 			goto out;
3691 		}
3692 		conf->reshape_progress = mddev->reshape_position;
3693 		if (conf->prev.far_offset)
3694 			conf->prev.stride = 1 << conf->prev.chunk_shift;
3695 		else
3696 			/* far_copies must be 1 */
3697 			conf->prev.stride = conf->dev_sectors;
3698 	}
3699 	conf->reshape_safe = conf->reshape_progress;
3700 	spin_lock_init(&conf->device_lock);
3701 	INIT_LIST_HEAD(&conf->retry_list);
3702 	INIT_LIST_HEAD(&conf->bio_end_io_list);
3703 
3704 	spin_lock_init(&conf->resync_lock);
3705 	init_waitqueue_head(&conf->wait_barrier);
3706 	atomic_set(&conf->nr_pending, 0);
3707 
3708 	err = -ENOMEM;
3709 	conf->thread = md_register_thread(raid10d, mddev, "raid10");
3710 	if (!conf->thread)
3711 		goto out;
3712 
3713 	conf->mddev = mddev;
3714 	return conf;
3715 
3716  out:
3717 	raid10_free_conf(conf);
3718 	return ERR_PTR(err);
3719 }
3720 
raid10_set_io_opt(struct r10conf * conf)3721 static void raid10_set_io_opt(struct r10conf *conf)
3722 {
3723 	int raid_disks = conf->geo.raid_disks;
3724 
3725 	if (!(conf->geo.raid_disks % conf->geo.near_copies))
3726 		raid_disks /= conf->geo.near_copies;
3727 	blk_queue_io_opt(conf->mddev->queue, (conf->mddev->chunk_sectors << 9) *
3728 			 raid_disks);
3729 }
3730 
raid10_run(struct mddev * mddev)3731 static int raid10_run(struct mddev *mddev)
3732 {
3733 	struct r10conf *conf;
3734 	int i, disk_idx;
3735 	struct raid10_info *disk;
3736 	struct md_rdev *rdev;
3737 	sector_t size;
3738 	sector_t min_offset_diff = 0;
3739 	int first = 1;
3740 	bool discard_supported = false;
3741 
3742 	if (mddev_init_writes_pending(mddev) < 0)
3743 		return -ENOMEM;
3744 
3745 	if (mddev->private == NULL) {
3746 		conf = setup_conf(mddev);
3747 		if (IS_ERR(conf))
3748 			return PTR_ERR(conf);
3749 		mddev->private = conf;
3750 	}
3751 	conf = mddev->private;
3752 	if (!conf)
3753 		goto out;
3754 
3755 	mddev->thread = conf->thread;
3756 	conf->thread = NULL;
3757 
3758 	if (mddev_is_clustered(conf->mddev)) {
3759 		int fc, fo;
3760 
3761 		fc = (mddev->layout >> 8) & 255;
3762 		fo = mddev->layout & (1<<16);
3763 		if (fc > 1 || fo > 0) {
3764 			pr_err("only near layout is supported by clustered"
3765 				" raid10\n");
3766 			goto out_free_conf;
3767 		}
3768 	}
3769 
3770 	if (mddev->queue) {
3771 		blk_queue_max_discard_sectors(mddev->queue,
3772 					      mddev->chunk_sectors);
3773 		blk_queue_max_write_same_sectors(mddev->queue, 0);
3774 		blk_queue_max_write_zeroes_sectors(mddev->queue, 0);
3775 		blk_queue_io_min(mddev->queue, mddev->chunk_sectors << 9);
3776 		raid10_set_io_opt(conf);
3777 	}
3778 
3779 	rdev_for_each(rdev, mddev) {
3780 		long long diff;
3781 
3782 		disk_idx = rdev->raid_disk;
3783 		if (disk_idx < 0)
3784 			continue;
3785 		if (disk_idx >= conf->geo.raid_disks &&
3786 		    disk_idx >= conf->prev.raid_disks)
3787 			continue;
3788 		disk = conf->mirrors + disk_idx;
3789 
3790 		if (test_bit(Replacement, &rdev->flags)) {
3791 			if (disk->replacement)
3792 				goto out_free_conf;
3793 			disk->replacement = rdev;
3794 		} else {
3795 			if (disk->rdev)
3796 				goto out_free_conf;
3797 			disk->rdev = rdev;
3798 		}
3799 		diff = (rdev->new_data_offset - rdev->data_offset);
3800 		if (!mddev->reshape_backwards)
3801 			diff = -diff;
3802 		if (diff < 0)
3803 			diff = 0;
3804 		if (first || diff < min_offset_diff)
3805 			min_offset_diff = diff;
3806 
3807 		if (mddev->gendisk)
3808 			disk_stack_limits(mddev->gendisk, rdev->bdev,
3809 					  rdev->data_offset << 9);
3810 
3811 		disk->head_position = 0;
3812 
3813 		if (blk_queue_discard(bdev_get_queue(rdev->bdev)))
3814 			discard_supported = true;
3815 		first = 0;
3816 	}
3817 
3818 	if (mddev->queue) {
3819 		if (discard_supported)
3820 			blk_queue_flag_set(QUEUE_FLAG_DISCARD,
3821 						mddev->queue);
3822 		else
3823 			blk_queue_flag_clear(QUEUE_FLAG_DISCARD,
3824 						  mddev->queue);
3825 	}
3826 	/* need to check that every block has at least one working mirror */
3827 	if (!enough(conf, -1)) {
3828 		pr_err("md/raid10:%s: not enough operational mirrors.\n",
3829 		       mdname(mddev));
3830 		goto out_free_conf;
3831 	}
3832 
3833 	if (conf->reshape_progress != MaxSector) {
3834 		/* must ensure that shape change is supported */
3835 		if (conf->geo.far_copies != 1 &&
3836 		    conf->geo.far_offset == 0)
3837 			goto out_free_conf;
3838 		if (conf->prev.far_copies != 1 &&
3839 		    conf->prev.far_offset == 0)
3840 			goto out_free_conf;
3841 	}
3842 
3843 	mddev->degraded = 0;
3844 	for (i = 0;
3845 	     i < conf->geo.raid_disks
3846 		     || i < conf->prev.raid_disks;
3847 	     i++) {
3848 
3849 		disk = conf->mirrors + i;
3850 
3851 		if (!disk->rdev && disk->replacement) {
3852 			/* The replacement is all we have - use it */
3853 			disk->rdev = disk->replacement;
3854 			disk->replacement = NULL;
3855 			clear_bit(Replacement, &disk->rdev->flags);
3856 		}
3857 
3858 		if (!disk->rdev ||
3859 		    !test_bit(In_sync, &disk->rdev->flags)) {
3860 			disk->head_position = 0;
3861 			mddev->degraded++;
3862 			if (disk->rdev &&
3863 			    disk->rdev->saved_raid_disk < 0)
3864 				conf->fullsync = 1;
3865 		}
3866 
3867 		if (disk->replacement &&
3868 		    !test_bit(In_sync, &disk->replacement->flags) &&
3869 		    disk->replacement->saved_raid_disk < 0) {
3870 			conf->fullsync = 1;
3871 		}
3872 
3873 		disk->recovery_disabled = mddev->recovery_disabled - 1;
3874 	}
3875 
3876 	if (mddev->recovery_cp != MaxSector)
3877 		pr_notice("md/raid10:%s: not clean -- starting background reconstruction\n",
3878 			  mdname(mddev));
3879 	pr_info("md/raid10:%s: active with %d out of %d devices\n",
3880 		mdname(mddev), conf->geo.raid_disks - mddev->degraded,
3881 		conf->geo.raid_disks);
3882 	/*
3883 	 * Ok, everything is just fine now
3884 	 */
3885 	mddev->dev_sectors = conf->dev_sectors;
3886 	size = raid10_size(mddev, 0, 0);
3887 	md_set_array_sectors(mddev, size);
3888 	mddev->resync_max_sectors = size;
3889 	set_bit(MD_FAILFAST_SUPPORTED, &mddev->flags);
3890 
3891 	if (md_integrity_register(mddev))
3892 		goto out_free_conf;
3893 
3894 	if (conf->reshape_progress != MaxSector) {
3895 		unsigned long before_length, after_length;
3896 
3897 		before_length = ((1 << conf->prev.chunk_shift) *
3898 				 conf->prev.far_copies);
3899 		after_length = ((1 << conf->geo.chunk_shift) *
3900 				conf->geo.far_copies);
3901 
3902 		if (max(before_length, after_length) > min_offset_diff) {
3903 			/* This cannot work */
3904 			pr_warn("md/raid10: offset difference not enough to continue reshape\n");
3905 			goto out_free_conf;
3906 		}
3907 		conf->offset_diff = min_offset_diff;
3908 
3909 		clear_bit(MD_RECOVERY_SYNC, &mddev->recovery);
3910 		clear_bit(MD_RECOVERY_CHECK, &mddev->recovery);
3911 		set_bit(MD_RECOVERY_RESHAPE, &mddev->recovery);
3912 		set_bit(MD_RECOVERY_RUNNING, &mddev->recovery);
3913 		mddev->sync_thread = md_register_thread(md_do_sync, mddev,
3914 							"reshape");
3915 		if (!mddev->sync_thread)
3916 			goto out_free_conf;
3917 	}
3918 
3919 	return 0;
3920 
3921 out_free_conf:
3922 	md_unregister_thread(&mddev->thread);
3923 	raid10_free_conf(conf);
3924 	mddev->private = NULL;
3925 out:
3926 	return -EIO;
3927 }
3928 
raid10_free(struct mddev * mddev,void * priv)3929 static void raid10_free(struct mddev *mddev, void *priv)
3930 {
3931 	raid10_free_conf(priv);
3932 }
3933 
raid10_quiesce(struct mddev * mddev,int quiesce)3934 static void raid10_quiesce(struct mddev *mddev, int quiesce)
3935 {
3936 	struct r10conf *conf = mddev->private;
3937 
3938 	if (quiesce)
3939 		raise_barrier(conf, 0);
3940 	else
3941 		lower_barrier(conf);
3942 }
3943 
raid10_resize(struct mddev * mddev,sector_t sectors)3944 static int raid10_resize(struct mddev *mddev, sector_t sectors)
3945 {
3946 	/* Resize of 'far' arrays is not supported.
3947 	 * For 'near' and 'offset' arrays we can set the
3948 	 * number of sectors used to be an appropriate multiple
3949 	 * of the chunk size.
3950 	 * For 'offset', this is far_copies*chunksize.
3951 	 * For 'near' the multiplier is the LCM of
3952 	 * near_copies and raid_disks.
3953 	 * So if far_copies > 1 && !far_offset, fail.
3954 	 * Else find LCM(raid_disks, near_copy)*far_copies and
3955 	 * multiply by chunk_size.  Then round to this number.
3956 	 * This is mostly done by raid10_size()
3957 	 */
3958 	struct r10conf *conf = mddev->private;
3959 	sector_t oldsize, size;
3960 
3961 	if (mddev->reshape_position != MaxSector)
3962 		return -EBUSY;
3963 
3964 	if (conf->geo.far_copies > 1 && !conf->geo.far_offset)
3965 		return -EINVAL;
3966 
3967 	oldsize = raid10_size(mddev, 0, 0);
3968 	size = raid10_size(mddev, sectors, 0);
3969 	if (mddev->external_size &&
3970 	    mddev->array_sectors > size)
3971 		return -EINVAL;
3972 	if (mddev->bitmap) {
3973 		int ret = md_bitmap_resize(mddev->bitmap, size, 0, 0);
3974 		if (ret)
3975 			return ret;
3976 	}
3977 	md_set_array_sectors(mddev, size);
3978 	if (sectors > mddev->dev_sectors &&
3979 	    mddev->recovery_cp > oldsize) {
3980 		mddev->recovery_cp = oldsize;
3981 		set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
3982 	}
3983 	calc_sectors(conf, sectors);
3984 	mddev->dev_sectors = conf->dev_sectors;
3985 	mddev->resync_max_sectors = size;
3986 	return 0;
3987 }
3988 
raid10_takeover_raid0(struct mddev * mddev,sector_t size,int devs)3989 static void *raid10_takeover_raid0(struct mddev *mddev, sector_t size, int devs)
3990 {
3991 	struct md_rdev *rdev;
3992 	struct r10conf *conf;
3993 
3994 	if (mddev->degraded > 0) {
3995 		pr_warn("md/raid10:%s: Error: degraded raid0!\n",
3996 			mdname(mddev));
3997 		return ERR_PTR(-EINVAL);
3998 	}
3999 	sector_div(size, devs);
4000 
4001 	/* Set new parameters */
4002 	mddev->new_level = 10;
4003 	/* new layout: far_copies = 1, near_copies = 2 */
4004 	mddev->new_layout = (1<<8) + 2;
4005 	mddev->new_chunk_sectors = mddev->chunk_sectors;
4006 	mddev->delta_disks = mddev->raid_disks;
4007 	mddev->raid_disks *= 2;
4008 	/* make sure it will be not marked as dirty */
4009 	mddev->recovery_cp = MaxSector;
4010 	mddev->dev_sectors = size;
4011 
4012 	conf = setup_conf(mddev);
4013 	if (!IS_ERR(conf)) {
4014 		rdev_for_each(rdev, mddev)
4015 			if (rdev->raid_disk >= 0) {
4016 				rdev->new_raid_disk = rdev->raid_disk * 2;
4017 				rdev->sectors = size;
4018 			}
4019 		conf->barrier = 1;
4020 	}
4021 
4022 	return conf;
4023 }
4024 
raid10_takeover(struct mddev * mddev)4025 static void *raid10_takeover(struct mddev *mddev)
4026 {
4027 	struct r0conf *raid0_conf;
4028 
4029 	/* raid10 can take over:
4030 	 *  raid0 - providing it has only two drives
4031 	 */
4032 	if (mddev->level == 0) {
4033 		/* for raid0 takeover only one zone is supported */
4034 		raid0_conf = mddev->private;
4035 		if (raid0_conf->nr_strip_zones > 1) {
4036 			pr_warn("md/raid10:%s: cannot takeover raid 0 with more than one zone.\n",
4037 				mdname(mddev));
4038 			return ERR_PTR(-EINVAL);
4039 		}
4040 		return raid10_takeover_raid0(mddev,
4041 			raid0_conf->strip_zone->zone_end,
4042 			raid0_conf->strip_zone->nb_dev);
4043 	}
4044 	return ERR_PTR(-EINVAL);
4045 }
4046 
raid10_check_reshape(struct mddev * mddev)4047 static int raid10_check_reshape(struct mddev *mddev)
4048 {
4049 	/* Called when there is a request to change
4050 	 * - layout (to ->new_layout)
4051 	 * - chunk size (to ->new_chunk_sectors)
4052 	 * - raid_disks (by delta_disks)
4053 	 * or when trying to restart a reshape that was ongoing.
4054 	 *
4055 	 * We need to validate the request and possibly allocate
4056 	 * space if that might be an issue later.
4057 	 *
4058 	 * Currently we reject any reshape of a 'far' mode array,
4059 	 * allow chunk size to change if new is generally acceptable,
4060 	 * allow raid_disks to increase, and allow
4061 	 * a switch between 'near' mode and 'offset' mode.
4062 	 */
4063 	struct r10conf *conf = mddev->private;
4064 	struct geom geo;
4065 
4066 	if (conf->geo.far_copies != 1 && !conf->geo.far_offset)
4067 		return -EINVAL;
4068 
4069 	if (setup_geo(&geo, mddev, geo_start) != conf->copies)
4070 		/* mustn't change number of copies */
4071 		return -EINVAL;
4072 	if (geo.far_copies > 1 && !geo.far_offset)
4073 		/* Cannot switch to 'far' mode */
4074 		return -EINVAL;
4075 
4076 	if (mddev->array_sectors & geo.chunk_mask)
4077 			/* not factor of array size */
4078 			return -EINVAL;
4079 
4080 	if (!enough(conf, -1))
4081 		return -EINVAL;
4082 
4083 	kfree(conf->mirrors_new);
4084 	conf->mirrors_new = NULL;
4085 	if (mddev->delta_disks > 0) {
4086 		/* allocate new 'mirrors' list */
4087 		conf->mirrors_new =
4088 			kcalloc(mddev->raid_disks + mddev->delta_disks,
4089 				sizeof(struct raid10_info),
4090 				GFP_KERNEL);
4091 		if (!conf->mirrors_new)
4092 			return -ENOMEM;
4093 	}
4094 	return 0;
4095 }
4096 
4097 /*
4098  * Need to check if array has failed when deciding whether to:
4099  *  - start an array
4100  *  - remove non-faulty devices
4101  *  - add a spare
4102  *  - allow a reshape
4103  * This determination is simple when no reshape is happening.
4104  * However if there is a reshape, we need to carefully check
4105  * both the before and after sections.
4106  * This is because some failed devices may only affect one
4107  * of the two sections, and some non-in_sync devices may
4108  * be insync in the section most affected by failed devices.
4109  */
calc_degraded(struct r10conf * conf)4110 static int calc_degraded(struct r10conf *conf)
4111 {
4112 	int degraded, degraded2;
4113 	int i;
4114 
4115 	rcu_read_lock();
4116 	degraded = 0;
4117 	/* 'prev' section first */
4118 	for (i = 0; i < conf->prev.raid_disks; i++) {
4119 		struct md_rdev *rdev = rcu_dereference(conf->mirrors[i].rdev);
4120 		if (!rdev || test_bit(Faulty, &rdev->flags))
4121 			degraded++;
4122 		else if (!test_bit(In_sync, &rdev->flags))
4123 			/* When we can reduce the number of devices in
4124 			 * an array, this might not contribute to
4125 			 * 'degraded'.  It does now.
4126 			 */
4127 			degraded++;
4128 	}
4129 	rcu_read_unlock();
4130 	if (conf->geo.raid_disks == conf->prev.raid_disks)
4131 		return degraded;
4132 	rcu_read_lock();
4133 	degraded2 = 0;
4134 	for (i = 0; i < conf->geo.raid_disks; i++) {
4135 		struct md_rdev *rdev = rcu_dereference(conf->mirrors[i].rdev);
4136 		if (!rdev || test_bit(Faulty, &rdev->flags))
4137 			degraded2++;
4138 		else if (!test_bit(In_sync, &rdev->flags)) {
4139 			/* If reshape is increasing the number of devices,
4140 			 * this section has already been recovered, so
4141 			 * it doesn't contribute to degraded.
4142 			 * else it does.
4143 			 */
4144 			if (conf->geo.raid_disks <= conf->prev.raid_disks)
4145 				degraded2++;
4146 		}
4147 	}
4148 	rcu_read_unlock();
4149 	if (degraded2 > degraded)
4150 		return degraded2;
4151 	return degraded;
4152 }
4153 
raid10_start_reshape(struct mddev * mddev)4154 static int raid10_start_reshape(struct mddev *mddev)
4155 {
4156 	/* A 'reshape' has been requested. This commits
4157 	 * the various 'new' fields and sets MD_RECOVER_RESHAPE
4158 	 * This also checks if there are enough spares and adds them
4159 	 * to the array.
4160 	 * We currently require enough spares to make the final
4161 	 * array non-degraded.  We also require that the difference
4162 	 * between old and new data_offset - on each device - is
4163 	 * enough that we never risk over-writing.
4164 	 */
4165 
4166 	unsigned long before_length, after_length;
4167 	sector_t min_offset_diff = 0;
4168 	int first = 1;
4169 	struct geom new;
4170 	struct r10conf *conf = mddev->private;
4171 	struct md_rdev *rdev;
4172 	int spares = 0;
4173 	int ret;
4174 
4175 	if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery))
4176 		return -EBUSY;
4177 
4178 	if (setup_geo(&new, mddev, geo_start) != conf->copies)
4179 		return -EINVAL;
4180 
4181 	before_length = ((1 << conf->prev.chunk_shift) *
4182 			 conf->prev.far_copies);
4183 	after_length = ((1 << conf->geo.chunk_shift) *
4184 			conf->geo.far_copies);
4185 
4186 	rdev_for_each(rdev, mddev) {
4187 		if (!test_bit(In_sync, &rdev->flags)
4188 		    && !test_bit(Faulty, &rdev->flags))
4189 			spares++;
4190 		if (rdev->raid_disk >= 0) {
4191 			long long diff = (rdev->new_data_offset
4192 					  - rdev->data_offset);
4193 			if (!mddev->reshape_backwards)
4194 				diff = -diff;
4195 			if (diff < 0)
4196 				diff = 0;
4197 			if (first || diff < min_offset_diff)
4198 				min_offset_diff = diff;
4199 			first = 0;
4200 		}
4201 	}
4202 
4203 	if (max(before_length, after_length) > min_offset_diff)
4204 		return -EINVAL;
4205 
4206 	if (spares < mddev->delta_disks)
4207 		return -EINVAL;
4208 
4209 	conf->offset_diff = min_offset_diff;
4210 	spin_lock_irq(&conf->device_lock);
4211 	if (conf->mirrors_new) {
4212 		memcpy(conf->mirrors_new, conf->mirrors,
4213 		       sizeof(struct raid10_info)*conf->prev.raid_disks);
4214 		smp_mb();
4215 		kfree(conf->mirrors_old);
4216 		conf->mirrors_old = conf->mirrors;
4217 		conf->mirrors = conf->mirrors_new;
4218 		conf->mirrors_new = NULL;
4219 	}
4220 	setup_geo(&conf->geo, mddev, geo_start);
4221 	smp_mb();
4222 	if (mddev->reshape_backwards) {
4223 		sector_t size = raid10_size(mddev, 0, 0);
4224 		if (size < mddev->array_sectors) {
4225 			spin_unlock_irq(&conf->device_lock);
4226 			pr_warn("md/raid10:%s: array size must be reduce before number of disks\n",
4227 				mdname(mddev));
4228 			return -EINVAL;
4229 		}
4230 		mddev->resync_max_sectors = size;
4231 		conf->reshape_progress = size;
4232 	} else
4233 		conf->reshape_progress = 0;
4234 	conf->reshape_safe = conf->reshape_progress;
4235 	spin_unlock_irq(&conf->device_lock);
4236 
4237 	if (mddev->delta_disks && mddev->bitmap) {
4238 		struct mdp_superblock_1 *sb = NULL;
4239 		sector_t oldsize, newsize;
4240 
4241 		oldsize = raid10_size(mddev, 0, 0);
4242 		newsize = raid10_size(mddev, 0, conf->geo.raid_disks);
4243 
4244 		if (!mddev_is_clustered(mddev)) {
4245 			ret = md_bitmap_resize(mddev->bitmap, newsize, 0, 0);
4246 			if (ret)
4247 				goto abort;
4248 			else
4249 				goto out;
4250 		}
4251 
4252 		rdev_for_each(rdev, mddev) {
4253 			if (rdev->raid_disk > -1 &&
4254 			    !test_bit(Faulty, &rdev->flags))
4255 				sb = page_address(rdev->sb_page);
4256 		}
4257 
4258 		/*
4259 		 * some node is already performing reshape, and no need to
4260 		 * call md_bitmap_resize again since it should be called when
4261 		 * receiving BITMAP_RESIZE msg
4262 		 */
4263 		if ((sb && (le32_to_cpu(sb->feature_map) &
4264 			    MD_FEATURE_RESHAPE_ACTIVE)) || (oldsize == newsize))
4265 			goto out;
4266 
4267 		ret = md_bitmap_resize(mddev->bitmap, newsize, 0, 0);
4268 		if (ret)
4269 			goto abort;
4270 
4271 		ret = md_cluster_ops->resize_bitmaps(mddev, newsize, oldsize);
4272 		if (ret) {
4273 			md_bitmap_resize(mddev->bitmap, oldsize, 0, 0);
4274 			goto abort;
4275 		}
4276 	}
4277 out:
4278 	if (mddev->delta_disks > 0) {
4279 		rdev_for_each(rdev, mddev)
4280 			if (rdev->raid_disk < 0 &&
4281 			    !test_bit(Faulty, &rdev->flags)) {
4282 				if (raid10_add_disk(mddev, rdev) == 0) {
4283 					if (rdev->raid_disk >=
4284 					    conf->prev.raid_disks)
4285 						set_bit(In_sync, &rdev->flags);
4286 					else
4287 						rdev->recovery_offset = 0;
4288 
4289 					/* Failure here is OK */
4290 					sysfs_link_rdev(mddev, rdev);
4291 				}
4292 			} else if (rdev->raid_disk >= conf->prev.raid_disks
4293 				   && !test_bit(Faulty, &rdev->flags)) {
4294 				/* This is a spare that was manually added */
4295 				set_bit(In_sync, &rdev->flags);
4296 			}
4297 	}
4298 	/* When a reshape changes the number of devices,
4299 	 * ->degraded is measured against the larger of the
4300 	 * pre and  post numbers.
4301 	 */
4302 	spin_lock_irq(&conf->device_lock);
4303 	mddev->degraded = calc_degraded(conf);
4304 	spin_unlock_irq(&conf->device_lock);
4305 	mddev->raid_disks = conf->geo.raid_disks;
4306 	mddev->reshape_position = conf->reshape_progress;
4307 	set_bit(MD_SB_CHANGE_DEVS, &mddev->sb_flags);
4308 
4309 	clear_bit(MD_RECOVERY_SYNC, &mddev->recovery);
4310 	clear_bit(MD_RECOVERY_CHECK, &mddev->recovery);
4311 	clear_bit(MD_RECOVERY_DONE, &mddev->recovery);
4312 	set_bit(MD_RECOVERY_RESHAPE, &mddev->recovery);
4313 	set_bit(MD_RECOVERY_RUNNING, &mddev->recovery);
4314 
4315 	mddev->sync_thread = md_register_thread(md_do_sync, mddev,
4316 						"reshape");
4317 	if (!mddev->sync_thread) {
4318 		ret = -EAGAIN;
4319 		goto abort;
4320 	}
4321 	conf->reshape_checkpoint = jiffies;
4322 	md_wakeup_thread(mddev->sync_thread);
4323 	md_new_event(mddev);
4324 	return 0;
4325 
4326 abort:
4327 	mddev->recovery = 0;
4328 	spin_lock_irq(&conf->device_lock);
4329 	conf->geo = conf->prev;
4330 	mddev->raid_disks = conf->geo.raid_disks;
4331 	rdev_for_each(rdev, mddev)
4332 		rdev->new_data_offset = rdev->data_offset;
4333 	smp_wmb();
4334 	conf->reshape_progress = MaxSector;
4335 	conf->reshape_safe = MaxSector;
4336 	mddev->reshape_position = MaxSector;
4337 	spin_unlock_irq(&conf->device_lock);
4338 	return ret;
4339 }
4340 
4341 /* Calculate the last device-address that could contain
4342  * any block from the chunk that includes the array-address 's'
4343  * and report the next address.
4344  * i.e. the address returned will be chunk-aligned and after
4345  * any data that is in the chunk containing 's'.
4346  */
last_dev_address(sector_t s,struct geom * geo)4347 static sector_t last_dev_address(sector_t s, struct geom *geo)
4348 {
4349 	s = (s | geo->chunk_mask) + 1;
4350 	s >>= geo->chunk_shift;
4351 	s *= geo->near_copies;
4352 	s = DIV_ROUND_UP_SECTOR_T(s, geo->raid_disks);
4353 	s *= geo->far_copies;
4354 	s <<= geo->chunk_shift;
4355 	return s;
4356 }
4357 
4358 /* Calculate the first device-address that could contain
4359  * any block from the chunk that includes the array-address 's'.
4360  * This too will be the start of a chunk
4361  */
first_dev_address(sector_t s,struct geom * geo)4362 static sector_t first_dev_address(sector_t s, struct geom *geo)
4363 {
4364 	s >>= geo->chunk_shift;
4365 	s *= geo->near_copies;
4366 	sector_div(s, geo->raid_disks);
4367 	s *= geo->far_copies;
4368 	s <<= geo->chunk_shift;
4369 	return s;
4370 }
4371 
reshape_request(struct mddev * mddev,sector_t sector_nr,int * skipped)4372 static sector_t reshape_request(struct mddev *mddev, sector_t sector_nr,
4373 				int *skipped)
4374 {
4375 	/* We simply copy at most one chunk (smallest of old and new)
4376 	 * at a time, possibly less if that exceeds RESYNC_PAGES,
4377 	 * or we hit a bad block or something.
4378 	 * This might mean we pause for normal IO in the middle of
4379 	 * a chunk, but that is not a problem as mddev->reshape_position
4380 	 * can record any location.
4381 	 *
4382 	 * If we will want to write to a location that isn't
4383 	 * yet recorded as 'safe' (i.e. in metadata on disk) then
4384 	 * we need to flush all reshape requests and update the metadata.
4385 	 *
4386 	 * When reshaping forwards (e.g. to more devices), we interpret
4387 	 * 'safe' as the earliest block which might not have been copied
4388 	 * down yet.  We divide this by previous stripe size and multiply
4389 	 * by previous stripe length to get lowest device offset that we
4390 	 * cannot write to yet.
4391 	 * We interpret 'sector_nr' as an address that we want to write to.
4392 	 * From this we use last_device_address() to find where we might
4393 	 * write to, and first_device_address on the  'safe' position.
4394 	 * If this 'next' write position is after the 'safe' position,
4395 	 * we must update the metadata to increase the 'safe' position.
4396 	 *
4397 	 * When reshaping backwards, we round in the opposite direction
4398 	 * and perform the reverse test:  next write position must not be
4399 	 * less than current safe position.
4400 	 *
4401 	 * In all this the minimum difference in data offsets
4402 	 * (conf->offset_diff - always positive) allows a bit of slack,
4403 	 * so next can be after 'safe', but not by more than offset_diff
4404 	 *
4405 	 * We need to prepare all the bios here before we start any IO
4406 	 * to ensure the size we choose is acceptable to all devices.
4407 	 * The means one for each copy for write-out and an extra one for
4408 	 * read-in.
4409 	 * We store the read-in bio in ->master_bio and the others in
4410 	 * ->devs[x].bio and ->devs[x].repl_bio.
4411 	 */
4412 	struct r10conf *conf = mddev->private;
4413 	struct r10bio *r10_bio;
4414 	sector_t next, safe, last;
4415 	int max_sectors;
4416 	int nr_sectors;
4417 	int s;
4418 	struct md_rdev *rdev;
4419 	int need_flush = 0;
4420 	struct bio *blist;
4421 	struct bio *bio, *read_bio;
4422 	int sectors_done = 0;
4423 	struct page **pages;
4424 
4425 	if (sector_nr == 0) {
4426 		/* If restarting in the middle, skip the initial sectors */
4427 		if (mddev->reshape_backwards &&
4428 		    conf->reshape_progress < raid10_size(mddev, 0, 0)) {
4429 			sector_nr = (raid10_size(mddev, 0, 0)
4430 				     - conf->reshape_progress);
4431 		} else if (!mddev->reshape_backwards &&
4432 			   conf->reshape_progress > 0)
4433 			sector_nr = conf->reshape_progress;
4434 		if (sector_nr) {
4435 			mddev->curr_resync_completed = sector_nr;
4436 			sysfs_notify_dirent_safe(mddev->sysfs_completed);
4437 			*skipped = 1;
4438 			return sector_nr;
4439 		}
4440 	}
4441 
4442 	/* We don't use sector_nr to track where we are up to
4443 	 * as that doesn't work well for ->reshape_backwards.
4444 	 * So just use ->reshape_progress.
4445 	 */
4446 	if (mddev->reshape_backwards) {
4447 		/* 'next' is the earliest device address that we might
4448 		 * write to for this chunk in the new layout
4449 		 */
4450 		next = first_dev_address(conf->reshape_progress - 1,
4451 					 &conf->geo);
4452 
4453 		/* 'safe' is the last device address that we might read from
4454 		 * in the old layout after a restart
4455 		 */
4456 		safe = last_dev_address(conf->reshape_safe - 1,
4457 					&conf->prev);
4458 
4459 		if (next + conf->offset_diff < safe)
4460 			need_flush = 1;
4461 
4462 		last = conf->reshape_progress - 1;
4463 		sector_nr = last & ~(sector_t)(conf->geo.chunk_mask
4464 					       & conf->prev.chunk_mask);
4465 		if (sector_nr + RESYNC_SECTORS < last)
4466 			sector_nr = last + 1 - RESYNC_SECTORS;
4467 	} else {
4468 		/* 'next' is after the last device address that we
4469 		 * might write to for this chunk in the new layout
4470 		 */
4471 		next = last_dev_address(conf->reshape_progress, &conf->geo);
4472 
4473 		/* 'safe' is the earliest device address that we might
4474 		 * read from in the old layout after a restart
4475 		 */
4476 		safe = first_dev_address(conf->reshape_safe, &conf->prev);
4477 
4478 		/* Need to update metadata if 'next' might be beyond 'safe'
4479 		 * as that would possibly corrupt data
4480 		 */
4481 		if (next > safe + conf->offset_diff)
4482 			need_flush = 1;
4483 
4484 		sector_nr = conf->reshape_progress;
4485 		last  = sector_nr | (conf->geo.chunk_mask
4486 				     & conf->prev.chunk_mask);
4487 
4488 		if (sector_nr + RESYNC_SECTORS <= last)
4489 			last = sector_nr + RESYNC_SECTORS - 1;
4490 	}
4491 
4492 	if (need_flush ||
4493 	    time_after(jiffies, conf->reshape_checkpoint + 10*HZ)) {
4494 		/* Need to update reshape_position in metadata */
4495 		wait_barrier(conf);
4496 		mddev->reshape_position = conf->reshape_progress;
4497 		if (mddev->reshape_backwards)
4498 			mddev->curr_resync_completed = raid10_size(mddev, 0, 0)
4499 				- conf->reshape_progress;
4500 		else
4501 			mddev->curr_resync_completed = conf->reshape_progress;
4502 		conf->reshape_checkpoint = jiffies;
4503 		set_bit(MD_SB_CHANGE_DEVS, &mddev->sb_flags);
4504 		md_wakeup_thread(mddev->thread);
4505 		wait_event(mddev->sb_wait, mddev->sb_flags == 0 ||
4506 			   test_bit(MD_RECOVERY_INTR, &mddev->recovery));
4507 		if (test_bit(MD_RECOVERY_INTR, &mddev->recovery)) {
4508 			allow_barrier(conf);
4509 			return sectors_done;
4510 		}
4511 		conf->reshape_safe = mddev->reshape_position;
4512 		allow_barrier(conf);
4513 	}
4514 
4515 	raise_barrier(conf, 0);
4516 read_more:
4517 	/* Now schedule reads for blocks from sector_nr to last */
4518 	r10_bio = raid10_alloc_init_r10buf(conf);
4519 	r10_bio->state = 0;
4520 	raise_barrier(conf, 1);
4521 	atomic_set(&r10_bio->remaining, 0);
4522 	r10_bio->mddev = mddev;
4523 	r10_bio->sector = sector_nr;
4524 	set_bit(R10BIO_IsReshape, &r10_bio->state);
4525 	r10_bio->sectors = last - sector_nr + 1;
4526 	rdev = read_balance(conf, r10_bio, &max_sectors);
4527 	BUG_ON(!test_bit(R10BIO_Previous, &r10_bio->state));
4528 
4529 	if (!rdev) {
4530 		/* Cannot read from here, so need to record bad blocks
4531 		 * on all the target devices.
4532 		 */
4533 		// FIXME
4534 		mempool_free(r10_bio, &conf->r10buf_pool);
4535 		set_bit(MD_RECOVERY_INTR, &mddev->recovery);
4536 		return sectors_done;
4537 	}
4538 
4539 	read_bio = bio_alloc_mddev(GFP_KERNEL, RESYNC_PAGES, mddev);
4540 
4541 	bio_set_dev(read_bio, rdev->bdev);
4542 	read_bio->bi_iter.bi_sector = (r10_bio->devs[r10_bio->read_slot].addr
4543 			       + rdev->data_offset);
4544 	read_bio->bi_private = r10_bio;
4545 	read_bio->bi_end_io = end_reshape_read;
4546 	bio_set_op_attrs(read_bio, REQ_OP_READ, 0);
4547 	read_bio->bi_flags &= (~0UL << BIO_RESET_BITS);
4548 	read_bio->bi_status = 0;
4549 	read_bio->bi_vcnt = 0;
4550 	read_bio->bi_iter.bi_size = 0;
4551 	r10_bio->master_bio = read_bio;
4552 	r10_bio->read_slot = r10_bio->devs[r10_bio->read_slot].devnum;
4553 
4554 	/*
4555 	 * Broadcast RESYNC message to other nodes, so all nodes would not
4556 	 * write to the region to avoid conflict.
4557 	*/
4558 	if (mddev_is_clustered(mddev) && conf->cluster_sync_high <= sector_nr) {
4559 		struct mdp_superblock_1 *sb = NULL;
4560 		int sb_reshape_pos = 0;
4561 
4562 		conf->cluster_sync_low = sector_nr;
4563 		conf->cluster_sync_high = sector_nr + CLUSTER_RESYNC_WINDOW_SECTORS;
4564 		sb = page_address(rdev->sb_page);
4565 		if (sb) {
4566 			sb_reshape_pos = le64_to_cpu(sb->reshape_position);
4567 			/*
4568 			 * Set cluster_sync_low again if next address for array
4569 			 * reshape is less than cluster_sync_low. Since we can't
4570 			 * update cluster_sync_low until it has finished reshape.
4571 			 */
4572 			if (sb_reshape_pos < conf->cluster_sync_low)
4573 				conf->cluster_sync_low = sb_reshape_pos;
4574 		}
4575 
4576 		md_cluster_ops->resync_info_update(mddev, conf->cluster_sync_low,
4577 							  conf->cluster_sync_high);
4578 	}
4579 
4580 	/* Now find the locations in the new layout */
4581 	__raid10_find_phys(&conf->geo, r10_bio);
4582 
4583 	blist = read_bio;
4584 	read_bio->bi_next = NULL;
4585 
4586 	rcu_read_lock();
4587 	for (s = 0; s < conf->copies*2; s++) {
4588 		struct bio *b;
4589 		int d = r10_bio->devs[s/2].devnum;
4590 		struct md_rdev *rdev2;
4591 		if (s&1) {
4592 			rdev2 = rcu_dereference(conf->mirrors[d].replacement);
4593 			b = r10_bio->devs[s/2].repl_bio;
4594 		} else {
4595 			rdev2 = rcu_dereference(conf->mirrors[d].rdev);
4596 			b = r10_bio->devs[s/2].bio;
4597 		}
4598 		if (!rdev2 || test_bit(Faulty, &rdev2->flags))
4599 			continue;
4600 
4601 		bio_set_dev(b, rdev2->bdev);
4602 		b->bi_iter.bi_sector = r10_bio->devs[s/2].addr +
4603 			rdev2->new_data_offset;
4604 		b->bi_end_io = end_reshape_write;
4605 		bio_set_op_attrs(b, REQ_OP_WRITE, 0);
4606 		b->bi_next = blist;
4607 		blist = b;
4608 	}
4609 
4610 	/* Now add as many pages as possible to all of these bios. */
4611 
4612 	nr_sectors = 0;
4613 	pages = get_resync_pages(r10_bio->devs[0].bio)->pages;
4614 	for (s = 0 ; s < max_sectors; s += PAGE_SIZE >> 9) {
4615 		struct page *page = pages[s / (PAGE_SIZE >> 9)];
4616 		int len = (max_sectors - s) << 9;
4617 		if (len > PAGE_SIZE)
4618 			len = PAGE_SIZE;
4619 		for (bio = blist; bio ; bio = bio->bi_next) {
4620 			/*
4621 			 * won't fail because the vec table is big enough
4622 			 * to hold all these pages
4623 			 */
4624 			bio_add_page(bio, page, len, 0);
4625 		}
4626 		sector_nr += len >> 9;
4627 		nr_sectors += len >> 9;
4628 	}
4629 	rcu_read_unlock();
4630 	r10_bio->sectors = nr_sectors;
4631 
4632 	/* Now submit the read */
4633 	md_sync_acct_bio(read_bio, r10_bio->sectors);
4634 	atomic_inc(&r10_bio->remaining);
4635 	read_bio->bi_next = NULL;
4636 	submit_bio_noacct(read_bio);
4637 	sectors_done += nr_sectors;
4638 	if (sector_nr <= last)
4639 		goto read_more;
4640 
4641 	lower_barrier(conf);
4642 
4643 	/* Now that we have done the whole section we can
4644 	 * update reshape_progress
4645 	 */
4646 	if (mddev->reshape_backwards)
4647 		conf->reshape_progress -= sectors_done;
4648 	else
4649 		conf->reshape_progress += sectors_done;
4650 
4651 	return sectors_done;
4652 }
4653 
4654 static void end_reshape_request(struct r10bio *r10_bio);
4655 static int handle_reshape_read_error(struct mddev *mddev,
4656 				     struct r10bio *r10_bio);
reshape_request_write(struct mddev * mddev,struct r10bio * r10_bio)4657 static void reshape_request_write(struct mddev *mddev, struct r10bio *r10_bio)
4658 {
4659 	/* Reshape read completed.  Hopefully we have a block
4660 	 * to write out.
4661 	 * If we got a read error then we do sync 1-page reads from
4662 	 * elsewhere until we find the data - or give up.
4663 	 */
4664 	struct r10conf *conf = mddev->private;
4665 	int s;
4666 
4667 	if (!test_bit(R10BIO_Uptodate, &r10_bio->state))
4668 		if (handle_reshape_read_error(mddev, r10_bio) < 0) {
4669 			/* Reshape has been aborted */
4670 			md_done_sync(mddev, r10_bio->sectors, 0);
4671 			return;
4672 		}
4673 
4674 	/* We definitely have the data in the pages, schedule the
4675 	 * writes.
4676 	 */
4677 	atomic_set(&r10_bio->remaining, 1);
4678 	for (s = 0; s < conf->copies*2; s++) {
4679 		struct bio *b;
4680 		int d = r10_bio->devs[s/2].devnum;
4681 		struct md_rdev *rdev;
4682 		rcu_read_lock();
4683 		if (s&1) {
4684 			rdev = rcu_dereference(conf->mirrors[d].replacement);
4685 			b = r10_bio->devs[s/2].repl_bio;
4686 		} else {
4687 			rdev = rcu_dereference(conf->mirrors[d].rdev);
4688 			b = r10_bio->devs[s/2].bio;
4689 		}
4690 		if (!rdev || test_bit(Faulty, &rdev->flags)) {
4691 			rcu_read_unlock();
4692 			continue;
4693 		}
4694 		atomic_inc(&rdev->nr_pending);
4695 		rcu_read_unlock();
4696 		md_sync_acct_bio(b, r10_bio->sectors);
4697 		atomic_inc(&r10_bio->remaining);
4698 		b->bi_next = NULL;
4699 		submit_bio_noacct(b);
4700 	}
4701 	end_reshape_request(r10_bio);
4702 }
4703 
end_reshape(struct r10conf * conf)4704 static void end_reshape(struct r10conf *conf)
4705 {
4706 	if (test_bit(MD_RECOVERY_INTR, &conf->mddev->recovery))
4707 		return;
4708 
4709 	spin_lock_irq(&conf->device_lock);
4710 	conf->prev = conf->geo;
4711 	md_finish_reshape(conf->mddev);
4712 	smp_wmb();
4713 	conf->reshape_progress = MaxSector;
4714 	conf->reshape_safe = MaxSector;
4715 	spin_unlock_irq(&conf->device_lock);
4716 
4717 	if (conf->mddev->queue)
4718 		raid10_set_io_opt(conf);
4719 	conf->fullsync = 0;
4720 }
4721 
raid10_update_reshape_pos(struct mddev * mddev)4722 static void raid10_update_reshape_pos(struct mddev *mddev)
4723 {
4724 	struct r10conf *conf = mddev->private;
4725 	sector_t lo, hi;
4726 
4727 	md_cluster_ops->resync_info_get(mddev, &lo, &hi);
4728 	if (((mddev->reshape_position <= hi) && (mddev->reshape_position >= lo))
4729 	    || mddev->reshape_position == MaxSector)
4730 		conf->reshape_progress = mddev->reshape_position;
4731 	else
4732 		WARN_ON_ONCE(1);
4733 }
4734 
handle_reshape_read_error(struct mddev * mddev,struct r10bio * r10_bio)4735 static int handle_reshape_read_error(struct mddev *mddev,
4736 				     struct r10bio *r10_bio)
4737 {
4738 	/* Use sync reads to get the blocks from somewhere else */
4739 	int sectors = r10_bio->sectors;
4740 	struct r10conf *conf = mddev->private;
4741 	struct r10bio *r10b;
4742 	int slot = 0;
4743 	int idx = 0;
4744 	struct page **pages;
4745 
4746 	r10b = kmalloc(struct_size(r10b, devs, conf->copies), GFP_NOIO);
4747 	if (!r10b) {
4748 		set_bit(MD_RECOVERY_INTR, &mddev->recovery);
4749 		return -ENOMEM;
4750 	}
4751 
4752 	/* reshape IOs share pages from .devs[0].bio */
4753 	pages = get_resync_pages(r10_bio->devs[0].bio)->pages;
4754 
4755 	r10b->sector = r10_bio->sector;
4756 	__raid10_find_phys(&conf->prev, r10b);
4757 
4758 	while (sectors) {
4759 		int s = sectors;
4760 		int success = 0;
4761 		int first_slot = slot;
4762 
4763 		if (s > (PAGE_SIZE >> 9))
4764 			s = PAGE_SIZE >> 9;
4765 
4766 		rcu_read_lock();
4767 		while (!success) {
4768 			int d = r10b->devs[slot].devnum;
4769 			struct md_rdev *rdev = rcu_dereference(conf->mirrors[d].rdev);
4770 			sector_t addr;
4771 			if (rdev == NULL ||
4772 			    test_bit(Faulty, &rdev->flags) ||
4773 			    !test_bit(In_sync, &rdev->flags))
4774 				goto failed;
4775 
4776 			addr = r10b->devs[slot].addr + idx * PAGE_SIZE;
4777 			atomic_inc(&rdev->nr_pending);
4778 			rcu_read_unlock();
4779 			success = sync_page_io(rdev,
4780 					       addr,
4781 					       s << 9,
4782 					       pages[idx],
4783 					       REQ_OP_READ, 0, false);
4784 			rdev_dec_pending(rdev, mddev);
4785 			rcu_read_lock();
4786 			if (success)
4787 				break;
4788 		failed:
4789 			slot++;
4790 			if (slot >= conf->copies)
4791 				slot = 0;
4792 			if (slot == first_slot)
4793 				break;
4794 		}
4795 		rcu_read_unlock();
4796 		if (!success) {
4797 			/* couldn't read this block, must give up */
4798 			set_bit(MD_RECOVERY_INTR,
4799 				&mddev->recovery);
4800 			kfree(r10b);
4801 			return -EIO;
4802 		}
4803 		sectors -= s;
4804 		idx++;
4805 	}
4806 	kfree(r10b);
4807 	return 0;
4808 }
4809 
end_reshape_write(struct bio * bio)4810 static void end_reshape_write(struct bio *bio)
4811 {
4812 	struct r10bio *r10_bio = get_resync_r10bio(bio);
4813 	struct mddev *mddev = r10_bio->mddev;
4814 	struct r10conf *conf = mddev->private;
4815 	int d;
4816 	int slot;
4817 	int repl;
4818 	struct md_rdev *rdev = NULL;
4819 
4820 	d = find_bio_disk(conf, r10_bio, bio, &slot, &repl);
4821 	if (repl)
4822 		rdev = conf->mirrors[d].replacement;
4823 	if (!rdev) {
4824 		smp_mb();
4825 		rdev = conf->mirrors[d].rdev;
4826 	}
4827 
4828 	if (bio->bi_status) {
4829 		/* FIXME should record badblock */
4830 		md_error(mddev, rdev);
4831 	}
4832 
4833 	rdev_dec_pending(rdev, mddev);
4834 	end_reshape_request(r10_bio);
4835 }
4836 
end_reshape_request(struct r10bio * r10_bio)4837 static void end_reshape_request(struct r10bio *r10_bio)
4838 {
4839 	if (!atomic_dec_and_test(&r10_bio->remaining))
4840 		return;
4841 	md_done_sync(r10_bio->mddev, r10_bio->sectors, 1);
4842 	bio_put(r10_bio->master_bio);
4843 	put_buf(r10_bio);
4844 }
4845 
raid10_finish_reshape(struct mddev * mddev)4846 static void raid10_finish_reshape(struct mddev *mddev)
4847 {
4848 	struct r10conf *conf = mddev->private;
4849 
4850 	if (test_bit(MD_RECOVERY_INTR, &mddev->recovery))
4851 		return;
4852 
4853 	if (mddev->delta_disks > 0) {
4854 		if (mddev->recovery_cp > mddev->resync_max_sectors) {
4855 			mddev->recovery_cp = mddev->resync_max_sectors;
4856 			set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
4857 		}
4858 		mddev->resync_max_sectors = mddev->array_sectors;
4859 	} else {
4860 		int d;
4861 		rcu_read_lock();
4862 		for (d = conf->geo.raid_disks ;
4863 		     d < conf->geo.raid_disks - mddev->delta_disks;
4864 		     d++) {
4865 			struct md_rdev *rdev = rcu_dereference(conf->mirrors[d].rdev);
4866 			if (rdev)
4867 				clear_bit(In_sync, &rdev->flags);
4868 			rdev = rcu_dereference(conf->mirrors[d].replacement);
4869 			if (rdev)
4870 				clear_bit(In_sync, &rdev->flags);
4871 		}
4872 		rcu_read_unlock();
4873 	}
4874 	mddev->layout = mddev->new_layout;
4875 	mddev->chunk_sectors = 1 << conf->geo.chunk_shift;
4876 	mddev->reshape_position = MaxSector;
4877 	mddev->delta_disks = 0;
4878 	mddev->reshape_backwards = 0;
4879 }
4880 
4881 static struct md_personality raid10_personality =
4882 {
4883 	.name		= "raid10",
4884 	.level		= 10,
4885 	.owner		= THIS_MODULE,
4886 	.make_request	= raid10_make_request,
4887 	.run		= raid10_run,
4888 	.free		= raid10_free,
4889 	.status		= raid10_status,
4890 	.error_handler	= raid10_error,
4891 	.hot_add_disk	= raid10_add_disk,
4892 	.hot_remove_disk= raid10_remove_disk,
4893 	.spare_active	= raid10_spare_active,
4894 	.sync_request	= raid10_sync_request,
4895 	.quiesce	= raid10_quiesce,
4896 	.size		= raid10_size,
4897 	.resize		= raid10_resize,
4898 	.takeover	= raid10_takeover,
4899 	.check_reshape	= raid10_check_reshape,
4900 	.start_reshape	= raid10_start_reshape,
4901 	.finish_reshape	= raid10_finish_reshape,
4902 	.update_reshape_pos = raid10_update_reshape_pos,
4903 };
4904 
raid_init(void)4905 static int __init raid_init(void)
4906 {
4907 	return register_md_personality(&raid10_personality);
4908 }
4909 
raid_exit(void)4910 static void raid_exit(void)
4911 {
4912 	unregister_md_personality(&raid10_personality);
4913 }
4914 
4915 module_init(raid_init);
4916 module_exit(raid_exit);
4917 MODULE_LICENSE("GPL");
4918 MODULE_DESCRIPTION("RAID10 (striped mirror) personality for MD");
4919 MODULE_ALIAS("md-personality-9"); /* RAID10 */
4920 MODULE_ALIAS("md-raid10");
4921 MODULE_ALIAS("md-level-10");
4922 
4923 module_param(max_queued_requests, int, S_IRUGO|S_IWUSR);
4924