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 >
755 		    rdev->recovery_offset) {
756 			/*
757 			 * Read replacement first to prevent reading both rdev
758 			 * and replacement as NULL during replacement replace
759 			 * rdev.
760 			 */
761 			smp_mb();
762 			rdev = rcu_dereference(conf->mirrors[disk].rdev);
763 		}
764 		if (rdev == NULL ||
765 		    test_bit(Faulty, &rdev->flags))
766 			continue;
767 		if (!test_bit(In_sync, &rdev->flags) &&
768 		    r10_bio->devs[slot].addr + sectors > rdev->recovery_offset)
769 			continue;
770 
771 		dev_sector = r10_bio->devs[slot].addr;
772 		if (is_badblock(rdev, dev_sector, sectors,
773 				&first_bad, &bad_sectors)) {
774 			if (best_dist < MaxSector)
775 				/* Already have a better slot */
776 				continue;
777 			if (first_bad <= dev_sector) {
778 				/* Cannot read here.  If this is the
779 				 * 'primary' device, then we must not read
780 				 * beyond 'bad_sectors' from another device.
781 				 */
782 				bad_sectors -= (dev_sector - first_bad);
783 				if (!do_balance && sectors > bad_sectors)
784 					sectors = bad_sectors;
785 				if (best_good_sectors > sectors)
786 					best_good_sectors = sectors;
787 			} else {
788 				sector_t good_sectors =
789 					first_bad - dev_sector;
790 				if (good_sectors > best_good_sectors) {
791 					best_good_sectors = good_sectors;
792 					best_dist_slot = slot;
793 					best_dist_rdev = rdev;
794 				}
795 				if (!do_balance)
796 					/* Must read from here */
797 					break;
798 			}
799 			continue;
800 		} else
801 			best_good_sectors = sectors;
802 
803 		if (!do_balance)
804 			break;
805 
806 		nonrot = blk_queue_nonrot(bdev_get_queue(rdev->bdev));
807 		has_nonrot_disk |= nonrot;
808 		pending = atomic_read(&rdev->nr_pending);
809 		if (min_pending > pending && nonrot) {
810 			min_pending = pending;
811 			best_pending_slot = slot;
812 			best_pending_rdev = rdev;
813 		}
814 
815 		if (best_dist_slot >= 0)
816 			/* At least 2 disks to choose from so failfast is OK */
817 			set_bit(R10BIO_FailFast, &r10_bio->state);
818 		/* This optimisation is debatable, and completely destroys
819 		 * sequential read speed for 'far copies' arrays.  So only
820 		 * keep it for 'near' arrays, and review those later.
821 		 */
822 		if (geo->near_copies > 1 && !pending)
823 			new_distance = 0;
824 
825 		/* for far > 1 always use the lowest address */
826 		else if (geo->far_copies > 1)
827 			new_distance = r10_bio->devs[slot].addr;
828 		else
829 			new_distance = abs(r10_bio->devs[slot].addr -
830 					   conf->mirrors[disk].head_position);
831 
832 		if (new_distance < best_dist) {
833 			best_dist = new_distance;
834 			best_dist_slot = slot;
835 			best_dist_rdev = rdev;
836 		}
837 	}
838 	if (slot >= conf->copies) {
839 		if (has_nonrot_disk) {
840 			slot = best_pending_slot;
841 			rdev = best_pending_rdev;
842 		} else {
843 			slot = best_dist_slot;
844 			rdev = best_dist_rdev;
845 		}
846 	}
847 
848 	if (slot >= 0) {
849 		atomic_inc(&rdev->nr_pending);
850 		r10_bio->read_slot = slot;
851 	} else
852 		rdev = NULL;
853 	rcu_read_unlock();
854 	*max_sectors = best_good_sectors;
855 
856 	return rdev;
857 }
858 
flush_pending_writes(struct r10conf *conf)859 static void flush_pending_writes(struct r10conf *conf)
860 {
861 	/* Any writes that have been queued but are awaiting
862 	 * bitmap updates get flushed here.
863 	 */
864 	spin_lock_irq(&conf->device_lock);
865 
866 	if (conf->pending_bio_list.head) {
867 		struct blk_plug plug;
868 		struct bio *bio;
869 
870 		bio = bio_list_get(&conf->pending_bio_list);
871 		conf->pending_count = 0;
872 		spin_unlock_irq(&conf->device_lock);
873 
874 		/*
875 		 * As this is called in a wait_event() loop (see freeze_array),
876 		 * current->state might be TASK_UNINTERRUPTIBLE which will
877 		 * cause a warning when we prepare to wait again.  As it is
878 		 * rare that this path is taken, it is perfectly safe to force
879 		 * us to go around the wait_event() loop again, so the warning
880 		 * is a false-positive. Silence the warning by resetting
881 		 * thread state
882 		 */
883 		__set_current_state(TASK_RUNNING);
884 
885 		blk_start_plug(&plug);
886 		/* flush any pending bitmap writes to disk
887 		 * before proceeding w/ I/O */
888 		md_bitmap_unplug(conf->mddev->bitmap);
889 		wake_up(&conf->wait_barrier);
890 
891 		while (bio) { /* submit pending writes */
892 			struct bio *next = bio->bi_next;
893 			struct md_rdev *rdev = (void*)bio->bi_disk;
894 			bio->bi_next = NULL;
895 			bio_set_dev(bio, rdev->bdev);
896 			if (test_bit(Faulty, &rdev->flags)) {
897 				bio_io_error(bio);
898 			} else if (unlikely((bio_op(bio) ==  REQ_OP_DISCARD) &&
899 					    !blk_queue_discard(bio->bi_disk->queue)))
900 				/* Just ignore it */
901 				bio_endio(bio);
902 			else
903 				submit_bio_noacct(bio);
904 			bio = next;
905 			cond_resched();
906 		}
907 		blk_finish_plug(&plug);
908 	} else
909 		spin_unlock_irq(&conf->device_lock);
910 }
911 
912 /* Barriers....
913  * Sometimes we need to suspend IO while we do something else,
914  * either some resync/recovery, or reconfigure the array.
915  * To do this we raise a 'barrier'.
916  * The 'barrier' is a counter that can be raised multiple times
917  * to count how many activities are happening which preclude
918  * normal IO.
919  * We can only raise the barrier if there is no pending IO.
920  * i.e. if nr_pending == 0.
921  * We choose only to raise the barrier if no-one is waiting for the
922  * barrier to go down.  This means that as soon as an IO request
923  * is ready, no other operations which require a barrier will start
924  * until the IO request has had a chance.
925  *
926  * So: regular IO calls 'wait_barrier'.  When that returns there
927  *    is no backgroup IO happening,  It must arrange to call
928  *    allow_barrier when it has finished its IO.
929  * backgroup IO calls must call raise_barrier.  Once that returns
930  *    there is no normal IO happeing.  It must arrange to call
931  *    lower_barrier when the particular background IO completes.
932  */
933 
raise_barrier(struct r10conf *conf, int force)934 static void raise_barrier(struct r10conf *conf, int force)
935 {
936 	BUG_ON(force && !conf->barrier);
937 	spin_lock_irq(&conf->resync_lock);
938 
939 	/* Wait until no block IO is waiting (unless 'force') */
940 	wait_event_lock_irq(conf->wait_barrier, force || !conf->nr_waiting,
941 			    conf->resync_lock);
942 
943 	/* block any new IO from starting */
944 	conf->barrier++;
945 
946 	/* Now wait for all pending IO to complete */
947 	wait_event_lock_irq(conf->wait_barrier,
948 			    !atomic_read(&conf->nr_pending) && conf->barrier < RESYNC_DEPTH,
949 			    conf->resync_lock);
950 
951 	spin_unlock_irq(&conf->resync_lock);
952 }
953 
lower_barrier(struct r10conf *conf)954 static void lower_barrier(struct r10conf *conf)
955 {
956 	unsigned long flags;
957 	spin_lock_irqsave(&conf->resync_lock, flags);
958 	conf->barrier--;
959 	spin_unlock_irqrestore(&conf->resync_lock, flags);
960 	wake_up(&conf->wait_barrier);
961 }
962 
wait_barrier(struct r10conf *conf)963 static void wait_barrier(struct r10conf *conf)
964 {
965 	spin_lock_irq(&conf->resync_lock);
966 	if (conf->barrier) {
967 		struct bio_list *bio_list = current->bio_list;
968 		conf->nr_waiting++;
969 		/* Wait for the barrier to drop.
970 		 * However if there are already pending
971 		 * requests (preventing the barrier from
972 		 * rising completely), and the
973 		 * pre-process bio queue isn't empty,
974 		 * then don't wait, as we need to empty
975 		 * that queue to get the nr_pending
976 		 * count down.
977 		 */
978 		raid10_log(conf->mddev, "wait barrier");
979 		wait_event_lock_irq(conf->wait_barrier,
980 				    !conf->barrier ||
981 				    (atomic_read(&conf->nr_pending) &&
982 				     bio_list &&
983 				     (!bio_list_empty(&bio_list[0]) ||
984 				      !bio_list_empty(&bio_list[1]))) ||
985 				     /* move on if recovery thread is
986 				      * blocked by us
987 				      */
988 				     (conf->mddev->thread->tsk == current &&
989 				      test_bit(MD_RECOVERY_RUNNING,
990 					       &conf->mddev->recovery) &&
991 				      conf->nr_queued > 0),
992 				    conf->resync_lock);
993 		conf->nr_waiting--;
994 		if (!conf->nr_waiting)
995 			wake_up(&conf->wait_barrier);
996 	}
997 	atomic_inc(&conf->nr_pending);
998 	spin_unlock_irq(&conf->resync_lock);
999 }
1000 
allow_barrier(struct r10conf *conf)1001 static void allow_barrier(struct r10conf *conf)
1002 {
1003 	if ((atomic_dec_and_test(&conf->nr_pending)) ||
1004 			(conf->array_freeze_pending))
1005 		wake_up(&conf->wait_barrier);
1006 }
1007 
freeze_array(struct r10conf *conf, int extra)1008 static void freeze_array(struct r10conf *conf, int extra)
1009 {
1010 	/* stop syncio and normal IO and wait for everything to
1011 	 * go quiet.
1012 	 * We increment barrier and nr_waiting, and then
1013 	 * wait until nr_pending match nr_queued+extra
1014 	 * This is called in the context of one normal IO request
1015 	 * that has failed. Thus any sync request that might be pending
1016 	 * will be blocked by nr_pending, and we need to wait for
1017 	 * pending IO requests to complete or be queued for re-try.
1018 	 * Thus the number queued (nr_queued) plus this request (extra)
1019 	 * must match the number of pending IOs (nr_pending) before
1020 	 * we continue.
1021 	 */
1022 	spin_lock_irq(&conf->resync_lock);
1023 	conf->array_freeze_pending++;
1024 	conf->barrier++;
1025 	conf->nr_waiting++;
1026 	wait_event_lock_irq_cmd(conf->wait_barrier,
1027 				atomic_read(&conf->nr_pending) == conf->nr_queued+extra,
1028 				conf->resync_lock,
1029 				flush_pending_writes(conf));
1030 
1031 	conf->array_freeze_pending--;
1032 	spin_unlock_irq(&conf->resync_lock);
1033 }
1034 
unfreeze_array(struct r10conf *conf)1035 static void unfreeze_array(struct r10conf *conf)
1036 {
1037 	/* reverse the effect of the freeze */
1038 	spin_lock_irq(&conf->resync_lock);
1039 	conf->barrier--;
1040 	conf->nr_waiting--;
1041 	wake_up(&conf->wait_barrier);
1042 	spin_unlock_irq(&conf->resync_lock);
1043 }
1044 
choose_data_offset(struct r10bio *r10_bio, struct md_rdev *rdev)1045 static sector_t choose_data_offset(struct r10bio *r10_bio,
1046 				   struct md_rdev *rdev)
1047 {
1048 	if (!test_bit(MD_RECOVERY_RESHAPE, &rdev->mddev->recovery) ||
1049 	    test_bit(R10BIO_Previous, &r10_bio->state))
1050 		return rdev->data_offset;
1051 	else
1052 		return rdev->new_data_offset;
1053 }
1054 
1055 struct raid10_plug_cb {
1056 	struct blk_plug_cb	cb;
1057 	struct bio_list		pending;
1058 	int			pending_cnt;
1059 };
1060 
raid10_unplug(struct blk_plug_cb *cb, bool from_schedule)1061 static void raid10_unplug(struct blk_plug_cb *cb, bool from_schedule)
1062 {
1063 	struct raid10_plug_cb *plug = container_of(cb, struct raid10_plug_cb,
1064 						   cb);
1065 	struct mddev *mddev = plug->cb.data;
1066 	struct r10conf *conf = mddev->private;
1067 	struct bio *bio;
1068 
1069 	if (from_schedule || current->bio_list) {
1070 		spin_lock_irq(&conf->device_lock);
1071 		bio_list_merge(&conf->pending_bio_list, &plug->pending);
1072 		conf->pending_count += plug->pending_cnt;
1073 		spin_unlock_irq(&conf->device_lock);
1074 		wake_up(&conf->wait_barrier);
1075 		md_wakeup_thread(mddev->thread);
1076 		kfree(plug);
1077 		return;
1078 	}
1079 
1080 	/* we aren't scheduling, so we can do the write-out directly. */
1081 	bio = bio_list_get(&plug->pending);
1082 	md_bitmap_unplug(mddev->bitmap);
1083 	wake_up(&conf->wait_barrier);
1084 
1085 	while (bio) { /* submit pending writes */
1086 		struct bio *next = bio->bi_next;
1087 		struct md_rdev *rdev = (void*)bio->bi_disk;
1088 		bio->bi_next = NULL;
1089 		bio_set_dev(bio, rdev->bdev);
1090 		if (test_bit(Faulty, &rdev->flags)) {
1091 			bio_io_error(bio);
1092 		} else if (unlikely((bio_op(bio) ==  REQ_OP_DISCARD) &&
1093 				    !blk_queue_discard(bio->bi_disk->queue)))
1094 			/* Just ignore it */
1095 			bio_endio(bio);
1096 		else
1097 			submit_bio_noacct(bio);
1098 		bio = next;
1099 		cond_resched();
1100 	}
1101 	kfree(plug);
1102 }
1103 
1104 /*
1105  * 1. Register the new request and wait if the reconstruction thread has put
1106  * up a bar for new requests. Continue immediately if no resync is active
1107  * currently.
1108  * 2. If IO spans the reshape position.  Need to wait for reshape to pass.
1109  */
regular_request_wait(struct mddev *mddev, struct r10conf *conf, struct bio *bio, sector_t sectors)1110 static void regular_request_wait(struct mddev *mddev, struct r10conf *conf,
1111 				 struct bio *bio, sector_t sectors)
1112 {
1113 	wait_barrier(conf);
1114 	while (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery) &&
1115 	    bio->bi_iter.bi_sector < conf->reshape_progress &&
1116 	    bio->bi_iter.bi_sector + sectors > conf->reshape_progress) {
1117 		raid10_log(conf->mddev, "wait reshape");
1118 		allow_barrier(conf);
1119 		wait_event(conf->wait_barrier,
1120 			   conf->reshape_progress <= bio->bi_iter.bi_sector ||
1121 			   conf->reshape_progress >= bio->bi_iter.bi_sector +
1122 			   sectors);
1123 		wait_barrier(conf);
1124 	}
1125 }
1126 
raid10_read_request(struct mddev *mddev, struct bio *bio, struct r10bio *r10_bio)1127 static void raid10_read_request(struct mddev *mddev, struct bio *bio,
1128 				struct r10bio *r10_bio)
1129 {
1130 	struct r10conf *conf = mddev->private;
1131 	struct bio *read_bio;
1132 	const int op = bio_op(bio);
1133 	const unsigned long do_sync = (bio->bi_opf & REQ_SYNC);
1134 	int max_sectors;
1135 	struct md_rdev *rdev;
1136 	char b[BDEVNAME_SIZE];
1137 	int slot = r10_bio->read_slot;
1138 	struct md_rdev *err_rdev = NULL;
1139 	gfp_t gfp = GFP_NOIO;
1140 
1141 	if (slot >= 0 && r10_bio->devs[slot].rdev) {
1142 		/*
1143 		 * This is an error retry, but we cannot
1144 		 * safely dereference the rdev in the r10_bio,
1145 		 * we must use the one in conf.
1146 		 * If it has already been disconnected (unlikely)
1147 		 * we lose the device name in error messages.
1148 		 */
1149 		int disk;
1150 		/*
1151 		 * As we are blocking raid10, it is a little safer to
1152 		 * use __GFP_HIGH.
1153 		 */
1154 		gfp = GFP_NOIO | __GFP_HIGH;
1155 
1156 		rcu_read_lock();
1157 		disk = r10_bio->devs[slot].devnum;
1158 		err_rdev = rcu_dereference(conf->mirrors[disk].rdev);
1159 		if (err_rdev)
1160 			bdevname(err_rdev->bdev, b);
1161 		else {
1162 			strcpy(b, "???");
1163 			/* This never gets dereferenced */
1164 			err_rdev = r10_bio->devs[slot].rdev;
1165 		}
1166 		rcu_read_unlock();
1167 	}
1168 
1169 	regular_request_wait(mddev, conf, bio, r10_bio->sectors);
1170 	rdev = read_balance(conf, r10_bio, &max_sectors);
1171 	if (!rdev) {
1172 		if (err_rdev) {
1173 			pr_crit_ratelimited("md/raid10:%s: %s: unrecoverable I/O read error for block %llu\n",
1174 					    mdname(mddev), b,
1175 					    (unsigned long long)r10_bio->sector);
1176 		}
1177 		raid_end_bio_io(r10_bio);
1178 		return;
1179 	}
1180 	if (err_rdev)
1181 		pr_err_ratelimited("md/raid10:%s: %s: redirecting sector %llu to another mirror\n",
1182 				   mdname(mddev),
1183 				   bdevname(rdev->bdev, b),
1184 				   (unsigned long long)r10_bio->sector);
1185 	if (max_sectors < bio_sectors(bio)) {
1186 		struct bio *split = bio_split(bio, max_sectors,
1187 					      gfp, &conf->bio_split);
1188 		bio_chain(split, bio);
1189 		allow_barrier(conf);
1190 		submit_bio_noacct(bio);
1191 		wait_barrier(conf);
1192 		bio = split;
1193 		r10_bio->master_bio = bio;
1194 		r10_bio->sectors = max_sectors;
1195 	}
1196 	slot = r10_bio->read_slot;
1197 
1198 	read_bio = bio_clone_fast(bio, gfp, &mddev->bio_set);
1199 
1200 	r10_bio->devs[slot].bio = read_bio;
1201 	r10_bio->devs[slot].rdev = rdev;
1202 
1203 	read_bio->bi_iter.bi_sector = r10_bio->devs[slot].addr +
1204 		choose_data_offset(r10_bio, rdev);
1205 	bio_set_dev(read_bio, rdev->bdev);
1206 	read_bio->bi_end_io = raid10_end_read_request;
1207 	bio_set_op_attrs(read_bio, op, do_sync);
1208 	if (test_bit(FailFast, &rdev->flags) &&
1209 	    test_bit(R10BIO_FailFast, &r10_bio->state))
1210 	        read_bio->bi_opf |= MD_FAILFAST;
1211 	read_bio->bi_private = r10_bio;
1212 
1213 	if (mddev->gendisk)
1214 	        trace_block_bio_remap(read_bio->bi_disk->queue,
1215 	                              read_bio, disk_devt(mddev->gendisk),
1216 	                              r10_bio->sector);
1217 	submit_bio_noacct(read_bio);
1218 	return;
1219 }
1220 
raid10_write_one_disk(struct mddev *mddev, struct r10bio *r10_bio, struct bio *bio, bool replacement, int n_copy)1221 static void raid10_write_one_disk(struct mddev *mddev, struct r10bio *r10_bio,
1222 				  struct bio *bio, bool replacement,
1223 				  int n_copy)
1224 {
1225 	const int op = bio_op(bio);
1226 	const unsigned long do_sync = (bio->bi_opf & REQ_SYNC);
1227 	const unsigned long do_fua = (bio->bi_opf & REQ_FUA);
1228 	unsigned long flags;
1229 	struct blk_plug_cb *cb;
1230 	struct raid10_plug_cb *plug = NULL;
1231 	struct r10conf *conf = mddev->private;
1232 	struct md_rdev *rdev;
1233 	int devnum = r10_bio->devs[n_copy].devnum;
1234 	struct bio *mbio;
1235 
1236 	if (replacement) {
1237 		rdev = conf->mirrors[devnum].replacement;
1238 		if (rdev == NULL) {
1239 			/* Replacement just got moved to main 'rdev' */
1240 			smp_mb();
1241 			rdev = conf->mirrors[devnum].rdev;
1242 		}
1243 	} else
1244 		rdev = conf->mirrors[devnum].rdev;
1245 
1246 	mbio = bio_clone_fast(bio, GFP_NOIO, &mddev->bio_set);
1247 	if (replacement)
1248 		r10_bio->devs[n_copy].repl_bio = mbio;
1249 	else
1250 		r10_bio->devs[n_copy].bio = mbio;
1251 
1252 	mbio->bi_iter.bi_sector	= (r10_bio->devs[n_copy].addr +
1253 				   choose_data_offset(r10_bio, rdev));
1254 	bio_set_dev(mbio, rdev->bdev);
1255 	mbio->bi_end_io	= raid10_end_write_request;
1256 	bio_set_op_attrs(mbio, op, do_sync | do_fua);
1257 	if (!replacement && test_bit(FailFast,
1258 				     &conf->mirrors[devnum].rdev->flags)
1259 			 && enough(conf, devnum))
1260 		mbio->bi_opf |= MD_FAILFAST;
1261 	mbio->bi_private = r10_bio;
1262 
1263 	if (conf->mddev->gendisk)
1264 		trace_block_bio_remap(mbio->bi_disk->queue,
1265 				      mbio, disk_devt(conf->mddev->gendisk),
1266 				      r10_bio->sector);
1267 	/* flush_pending_writes() needs access to the rdev so...*/
1268 	mbio->bi_disk = (void *)rdev;
1269 
1270 	atomic_inc(&r10_bio->remaining);
1271 
1272 	cb = blk_check_plugged(raid10_unplug, mddev, sizeof(*plug));
1273 	if (cb)
1274 		plug = container_of(cb, struct raid10_plug_cb, cb);
1275 	else
1276 		plug = NULL;
1277 	if (plug) {
1278 		bio_list_add(&plug->pending, mbio);
1279 		plug->pending_cnt++;
1280 	} else {
1281 		spin_lock_irqsave(&conf->device_lock, flags);
1282 		bio_list_add(&conf->pending_bio_list, mbio);
1283 		conf->pending_count++;
1284 		spin_unlock_irqrestore(&conf->device_lock, flags);
1285 		md_wakeup_thread(mddev->thread);
1286 	}
1287 }
1288 
raid10_write_request(struct mddev *mddev, struct bio *bio, struct r10bio *r10_bio)1289 static void raid10_write_request(struct mddev *mddev, struct bio *bio,
1290 				 struct r10bio *r10_bio)
1291 {
1292 	struct r10conf *conf = mddev->private;
1293 	int i;
1294 	struct md_rdev *blocked_rdev;
1295 	sector_t sectors;
1296 	int max_sectors;
1297 
1298 	if ((mddev_is_clustered(mddev) &&
1299 	     md_cluster_ops->area_resyncing(mddev, WRITE,
1300 					    bio->bi_iter.bi_sector,
1301 					    bio_end_sector(bio)))) {
1302 		DEFINE_WAIT(w);
1303 		for (;;) {
1304 			prepare_to_wait(&conf->wait_barrier,
1305 					&w, TASK_IDLE);
1306 			if (!md_cluster_ops->area_resyncing(mddev, WRITE,
1307 				 bio->bi_iter.bi_sector, bio_end_sector(bio)))
1308 				break;
1309 			schedule();
1310 		}
1311 		finish_wait(&conf->wait_barrier, &w);
1312 	}
1313 
1314 	sectors = r10_bio->sectors;
1315 	regular_request_wait(mddev, conf, bio, sectors);
1316 	if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery) &&
1317 	    (mddev->reshape_backwards
1318 	     ? (bio->bi_iter.bi_sector < conf->reshape_safe &&
1319 		bio->bi_iter.bi_sector + sectors > conf->reshape_progress)
1320 	     : (bio->bi_iter.bi_sector + sectors > conf->reshape_safe &&
1321 		bio->bi_iter.bi_sector < conf->reshape_progress))) {
1322 		/* Need to update reshape_position in metadata */
1323 		mddev->reshape_position = conf->reshape_progress;
1324 		set_mask_bits(&mddev->sb_flags, 0,
1325 			      BIT(MD_SB_CHANGE_DEVS) | BIT(MD_SB_CHANGE_PENDING));
1326 		md_wakeup_thread(mddev->thread);
1327 		raid10_log(conf->mddev, "wait reshape metadata");
1328 		wait_event(mddev->sb_wait,
1329 			   !test_bit(MD_SB_CHANGE_PENDING, &mddev->sb_flags));
1330 
1331 		conf->reshape_safe = mddev->reshape_position;
1332 	}
1333 
1334 	if (conf->pending_count >= max_queued_requests) {
1335 		md_wakeup_thread(mddev->thread);
1336 		raid10_log(mddev, "wait queued");
1337 		wait_event(conf->wait_barrier,
1338 			   conf->pending_count < max_queued_requests);
1339 	}
1340 	/* first select target devices under rcu_lock and
1341 	 * inc refcount on their rdev.  Record them by setting
1342 	 * bios[x] to bio
1343 	 * If there are known/acknowledged bad blocks on any device
1344 	 * on which we have seen a write error, we want to avoid
1345 	 * writing to those blocks.  This potentially requires several
1346 	 * writes to write around the bad blocks.  Each set of writes
1347 	 * gets its own r10_bio with a set of bios attached.
1348 	 */
1349 
1350 	r10_bio->read_slot = -1; /* make sure repl_bio gets freed */
1351 	raid10_find_phys(conf, r10_bio);
1352 retry_write:
1353 	blocked_rdev = NULL;
1354 	rcu_read_lock();
1355 	max_sectors = r10_bio->sectors;
1356 
1357 	for (i = 0;  i < conf->copies; i++) {
1358 		int d = r10_bio->devs[i].devnum;
1359 		struct md_rdev *rdev, *rrdev;
1360 
1361 		rrdev = rcu_dereference(conf->mirrors[d].replacement);
1362 		/*
1363 		 * Read replacement first to prevent reading both rdev and
1364 		 * replacement as NULL during replacement replace rdev.
1365 		 */
1366 		smp_mb();
1367 		rdev = rcu_dereference(conf->mirrors[d].rdev);
1368 		if (rdev == rrdev)
1369 			rrdev = NULL;
1370 		if (rdev && unlikely(test_bit(Blocked, &rdev->flags))) {
1371 			atomic_inc(&rdev->nr_pending);
1372 			blocked_rdev = rdev;
1373 			break;
1374 		}
1375 		if (rrdev && unlikely(test_bit(Blocked, &rrdev->flags))) {
1376 			atomic_inc(&rrdev->nr_pending);
1377 			blocked_rdev = rrdev;
1378 			break;
1379 		}
1380 		if (rdev && (test_bit(Faulty, &rdev->flags)))
1381 			rdev = NULL;
1382 		if (rrdev && (test_bit(Faulty, &rrdev->flags)))
1383 			rrdev = NULL;
1384 
1385 		r10_bio->devs[i].bio = NULL;
1386 		r10_bio->devs[i].repl_bio = NULL;
1387 
1388 		if (!rdev && !rrdev) {
1389 			set_bit(R10BIO_Degraded, &r10_bio->state);
1390 			continue;
1391 		}
1392 		if (rdev && test_bit(WriteErrorSeen, &rdev->flags)) {
1393 			sector_t first_bad;
1394 			sector_t dev_sector = r10_bio->devs[i].addr;
1395 			int bad_sectors;
1396 			int is_bad;
1397 
1398 			is_bad = is_badblock(rdev, dev_sector, max_sectors,
1399 					     &first_bad, &bad_sectors);
1400 			if (is_bad < 0) {
1401 				/* Mustn't write here until the bad block
1402 				 * is acknowledged
1403 				 */
1404 				atomic_inc(&rdev->nr_pending);
1405 				set_bit(BlockedBadBlocks, &rdev->flags);
1406 				blocked_rdev = rdev;
1407 				break;
1408 			}
1409 			if (is_bad && first_bad <= dev_sector) {
1410 				/* Cannot write here at all */
1411 				bad_sectors -= (dev_sector - first_bad);
1412 				if (bad_sectors < max_sectors)
1413 					/* Mustn't write more than bad_sectors
1414 					 * to other devices yet
1415 					 */
1416 					max_sectors = bad_sectors;
1417 				/* We don't set R10BIO_Degraded as that
1418 				 * only applies if the disk is missing,
1419 				 * so it might be re-added, and we want to
1420 				 * know to recover this chunk.
1421 				 * In this case the device is here, and the
1422 				 * fact that this chunk is not in-sync is
1423 				 * recorded in the bad block log.
1424 				 */
1425 				continue;
1426 			}
1427 			if (is_bad) {
1428 				int good_sectors = first_bad - dev_sector;
1429 				if (good_sectors < max_sectors)
1430 					max_sectors = good_sectors;
1431 			}
1432 		}
1433 		if (rdev) {
1434 			r10_bio->devs[i].bio = bio;
1435 			atomic_inc(&rdev->nr_pending);
1436 		}
1437 		if (rrdev) {
1438 			r10_bio->devs[i].repl_bio = bio;
1439 			atomic_inc(&rrdev->nr_pending);
1440 		}
1441 	}
1442 	rcu_read_unlock();
1443 
1444 	if (unlikely(blocked_rdev)) {
1445 		/* Have to wait for this device to get unblocked, then retry */
1446 		int j;
1447 		int d;
1448 
1449 		for (j = 0; j < i; j++) {
1450 			if (r10_bio->devs[j].bio) {
1451 				d = r10_bio->devs[j].devnum;
1452 				rdev_dec_pending(conf->mirrors[d].rdev, mddev);
1453 			}
1454 			if (r10_bio->devs[j].repl_bio) {
1455 				struct md_rdev *rdev;
1456 				d = r10_bio->devs[j].devnum;
1457 				rdev = conf->mirrors[d].replacement;
1458 				if (!rdev) {
1459 					/* Race with remove_disk */
1460 					smp_mb();
1461 					rdev = conf->mirrors[d].rdev;
1462 				}
1463 				rdev_dec_pending(rdev, mddev);
1464 			}
1465 		}
1466 		allow_barrier(conf);
1467 		raid10_log(conf->mddev, "wait rdev %d blocked", blocked_rdev->raid_disk);
1468 		md_wait_for_blocked_rdev(blocked_rdev, mddev);
1469 		wait_barrier(conf);
1470 		goto retry_write;
1471 	}
1472 
1473 	if (max_sectors < r10_bio->sectors)
1474 		r10_bio->sectors = max_sectors;
1475 
1476 	if (r10_bio->sectors < bio_sectors(bio)) {
1477 		struct bio *split = bio_split(bio, r10_bio->sectors,
1478 					      GFP_NOIO, &conf->bio_split);
1479 		bio_chain(split, bio);
1480 		allow_barrier(conf);
1481 		submit_bio_noacct(bio);
1482 		wait_barrier(conf);
1483 		bio = split;
1484 		r10_bio->master_bio = bio;
1485 	}
1486 
1487 	atomic_set(&r10_bio->remaining, 1);
1488 	md_bitmap_startwrite(mddev->bitmap, r10_bio->sector, r10_bio->sectors, 0);
1489 
1490 	for (i = 0; i < conf->copies; i++) {
1491 		if (r10_bio->devs[i].bio)
1492 			raid10_write_one_disk(mddev, r10_bio, bio, false, i);
1493 		if (r10_bio->devs[i].repl_bio)
1494 			raid10_write_one_disk(mddev, r10_bio, bio, true, i);
1495 	}
1496 	one_write_done(r10_bio);
1497 }
1498 
__make_request(struct mddev *mddev, struct bio *bio, int sectors)1499 static void __make_request(struct mddev *mddev, struct bio *bio, int sectors)
1500 {
1501 	struct r10conf *conf = mddev->private;
1502 	struct r10bio *r10_bio;
1503 
1504 	r10_bio = mempool_alloc(&conf->r10bio_pool, GFP_NOIO);
1505 
1506 	r10_bio->master_bio = bio;
1507 	r10_bio->sectors = sectors;
1508 
1509 	r10_bio->mddev = mddev;
1510 	r10_bio->sector = bio->bi_iter.bi_sector;
1511 	r10_bio->state = 0;
1512 	r10_bio->read_slot = -1;
1513 	memset(r10_bio->devs, 0, sizeof(r10_bio->devs[0]) * conf->copies);
1514 
1515 	if (bio_data_dir(bio) == READ)
1516 		raid10_read_request(mddev, bio, r10_bio);
1517 	else
1518 		raid10_write_request(mddev, bio, r10_bio);
1519 }
1520 
raid10_make_request(struct mddev *mddev, struct bio *bio)1521 static bool raid10_make_request(struct mddev *mddev, struct bio *bio)
1522 {
1523 	struct r10conf *conf = mddev->private;
1524 	sector_t chunk_mask = (conf->geo.chunk_mask & conf->prev.chunk_mask);
1525 	int chunk_sects = chunk_mask + 1;
1526 	int sectors = bio_sectors(bio);
1527 
1528 	if (unlikely(bio->bi_opf & REQ_PREFLUSH)
1529 	    && md_flush_request(mddev, bio))
1530 		return true;
1531 
1532 	if (!md_write_start(mddev, bio))
1533 		return false;
1534 
1535 	/*
1536 	 * If this request crosses a chunk boundary, we need to split
1537 	 * it.
1538 	 */
1539 	if (unlikely((bio->bi_iter.bi_sector & chunk_mask) +
1540 		     sectors > chunk_sects
1541 		     && (conf->geo.near_copies < conf->geo.raid_disks
1542 			 || conf->prev.near_copies <
1543 			 conf->prev.raid_disks)))
1544 		sectors = chunk_sects -
1545 			(bio->bi_iter.bi_sector &
1546 			 (chunk_sects - 1));
1547 	__make_request(mddev, bio, sectors);
1548 
1549 	/* In case raid10d snuck in to freeze_array */
1550 	wake_up(&conf->wait_barrier);
1551 	return true;
1552 }
1553 
raid10_status(struct seq_file *seq, struct mddev *mddev)1554 static void raid10_status(struct seq_file *seq, struct mddev *mddev)
1555 {
1556 	struct r10conf *conf = mddev->private;
1557 	int i;
1558 
1559 	if (conf->geo.near_copies < conf->geo.raid_disks)
1560 		seq_printf(seq, " %dK chunks", mddev->chunk_sectors / 2);
1561 	if (conf->geo.near_copies > 1)
1562 		seq_printf(seq, " %d near-copies", conf->geo.near_copies);
1563 	if (conf->geo.far_copies > 1) {
1564 		if (conf->geo.far_offset)
1565 			seq_printf(seq, " %d offset-copies", conf->geo.far_copies);
1566 		else
1567 			seq_printf(seq, " %d far-copies", conf->geo.far_copies);
1568 		if (conf->geo.far_set_size != conf->geo.raid_disks)
1569 			seq_printf(seq, " %d devices per set", conf->geo.far_set_size);
1570 	}
1571 	seq_printf(seq, " [%d/%d] [", conf->geo.raid_disks,
1572 					conf->geo.raid_disks - mddev->degraded);
1573 	rcu_read_lock();
1574 	for (i = 0; i < conf->geo.raid_disks; i++) {
1575 		struct md_rdev *rdev = rcu_dereference(conf->mirrors[i].rdev);
1576 		seq_printf(seq, "%s", rdev && test_bit(In_sync, &rdev->flags) ? "U" : "_");
1577 	}
1578 	rcu_read_unlock();
1579 	seq_printf(seq, "]");
1580 }
1581 
1582 /* check if there are enough drives for
1583  * every block to appear on atleast one.
1584  * Don't consider the device numbered 'ignore'
1585  * as we might be about to remove it.
1586  */
_enough(struct r10conf *conf, int previous, int ignore)1587 static int _enough(struct r10conf *conf, int previous, int ignore)
1588 {
1589 	int first = 0;
1590 	int has_enough = 0;
1591 	int disks, ncopies;
1592 	if (previous) {
1593 		disks = conf->prev.raid_disks;
1594 		ncopies = conf->prev.near_copies;
1595 	} else {
1596 		disks = conf->geo.raid_disks;
1597 		ncopies = conf->geo.near_copies;
1598 	}
1599 
1600 	rcu_read_lock();
1601 	do {
1602 		int n = conf->copies;
1603 		int cnt = 0;
1604 		int this = first;
1605 		while (n--) {
1606 			struct md_rdev *rdev;
1607 			if (this != ignore &&
1608 			    (rdev = rcu_dereference(conf->mirrors[this].rdev)) &&
1609 			    test_bit(In_sync, &rdev->flags))
1610 				cnt++;
1611 			this = (this+1) % disks;
1612 		}
1613 		if (cnt == 0)
1614 			goto out;
1615 		first = (first + ncopies) % disks;
1616 	} while (first != 0);
1617 	has_enough = 1;
1618 out:
1619 	rcu_read_unlock();
1620 	return has_enough;
1621 }
1622 
enough(struct r10conf *conf, int ignore)1623 static int enough(struct r10conf *conf, int ignore)
1624 {
1625 	/* when calling 'enough', both 'prev' and 'geo' must
1626 	 * be stable.
1627 	 * This is ensured if ->reconfig_mutex or ->device_lock
1628 	 * is held.
1629 	 */
1630 	return _enough(conf, 0, ignore) &&
1631 		_enough(conf, 1, ignore);
1632 }
1633 
raid10_error(struct mddev *mddev, struct md_rdev *rdev)1634 static void raid10_error(struct mddev *mddev, struct md_rdev *rdev)
1635 {
1636 	char b[BDEVNAME_SIZE];
1637 	struct r10conf *conf = mddev->private;
1638 	unsigned long flags;
1639 
1640 	/*
1641 	 * If it is not operational, then we have already marked it as dead
1642 	 * else if it is the last working disks with "fail_last_dev == false",
1643 	 * ignore the error, let the next level up know.
1644 	 * else mark the drive as failed
1645 	 */
1646 	spin_lock_irqsave(&conf->device_lock, flags);
1647 	if (test_bit(In_sync, &rdev->flags) && !mddev->fail_last_dev
1648 	    && !enough(conf, rdev->raid_disk)) {
1649 		/*
1650 		 * Don't fail the drive, just return an IO error.
1651 		 */
1652 		spin_unlock_irqrestore(&conf->device_lock, flags);
1653 		return;
1654 	}
1655 	if (test_and_clear_bit(In_sync, &rdev->flags))
1656 		mddev->degraded++;
1657 	/*
1658 	 * If recovery is running, make sure it aborts.
1659 	 */
1660 	set_bit(MD_RECOVERY_INTR, &mddev->recovery);
1661 	set_bit(Blocked, &rdev->flags);
1662 	set_bit(Faulty, &rdev->flags);
1663 	set_mask_bits(&mddev->sb_flags, 0,
1664 		      BIT(MD_SB_CHANGE_DEVS) | BIT(MD_SB_CHANGE_PENDING));
1665 	spin_unlock_irqrestore(&conf->device_lock, flags);
1666 	pr_crit("md/raid10:%s: Disk failure on %s, disabling device.\n"
1667 		"md/raid10:%s: Operation continuing on %d devices.\n",
1668 		mdname(mddev), bdevname(rdev->bdev, b),
1669 		mdname(mddev), conf->geo.raid_disks - mddev->degraded);
1670 }
1671 
print_conf(struct r10conf *conf)1672 static void print_conf(struct r10conf *conf)
1673 {
1674 	int i;
1675 	struct md_rdev *rdev;
1676 
1677 	pr_debug("RAID10 conf printout:\n");
1678 	if (!conf) {
1679 		pr_debug("(!conf)\n");
1680 		return;
1681 	}
1682 	pr_debug(" --- wd:%d rd:%d\n", conf->geo.raid_disks - conf->mddev->degraded,
1683 		 conf->geo.raid_disks);
1684 
1685 	/* This is only called with ->reconfix_mutex held, so
1686 	 * rcu protection of rdev is not needed */
1687 	for (i = 0; i < conf->geo.raid_disks; i++) {
1688 		char b[BDEVNAME_SIZE];
1689 		rdev = conf->mirrors[i].rdev;
1690 		if (rdev)
1691 			pr_debug(" disk %d, wo:%d, o:%d, dev:%s\n",
1692 				 i, !test_bit(In_sync, &rdev->flags),
1693 				 !test_bit(Faulty, &rdev->flags),
1694 				 bdevname(rdev->bdev,b));
1695 	}
1696 }
1697 
close_sync(struct r10conf *conf)1698 static void close_sync(struct r10conf *conf)
1699 {
1700 	wait_barrier(conf);
1701 	allow_barrier(conf);
1702 
1703 	mempool_exit(&conf->r10buf_pool);
1704 }
1705 
raid10_spare_active(struct mddev *mddev)1706 static int raid10_spare_active(struct mddev *mddev)
1707 {
1708 	int i;
1709 	struct r10conf *conf = mddev->private;
1710 	struct raid10_info *tmp;
1711 	int count = 0;
1712 	unsigned long flags;
1713 
1714 	/*
1715 	 * Find all non-in_sync disks within the RAID10 configuration
1716 	 * and mark them in_sync
1717 	 */
1718 	for (i = 0; i < conf->geo.raid_disks; i++) {
1719 		tmp = conf->mirrors + i;
1720 		if (tmp->replacement
1721 		    && tmp->replacement->recovery_offset == MaxSector
1722 		    && !test_bit(Faulty, &tmp->replacement->flags)
1723 		    && !test_and_set_bit(In_sync, &tmp->replacement->flags)) {
1724 			/* Replacement has just become active */
1725 			if (!tmp->rdev
1726 			    || !test_and_clear_bit(In_sync, &tmp->rdev->flags))
1727 				count++;
1728 			if (tmp->rdev) {
1729 				/* Replaced device not technically faulty,
1730 				 * but we need to be sure it gets removed
1731 				 * and never re-added.
1732 				 */
1733 				set_bit(Faulty, &tmp->rdev->flags);
1734 				sysfs_notify_dirent_safe(
1735 					tmp->rdev->sysfs_state);
1736 			}
1737 			sysfs_notify_dirent_safe(tmp->replacement->sysfs_state);
1738 		} else if (tmp->rdev
1739 			   && tmp->rdev->recovery_offset == MaxSector
1740 			   && !test_bit(Faulty, &tmp->rdev->flags)
1741 			   && !test_and_set_bit(In_sync, &tmp->rdev->flags)) {
1742 			count++;
1743 			sysfs_notify_dirent_safe(tmp->rdev->sysfs_state);
1744 		}
1745 	}
1746 	spin_lock_irqsave(&conf->device_lock, flags);
1747 	mddev->degraded -= count;
1748 	spin_unlock_irqrestore(&conf->device_lock, flags);
1749 
1750 	print_conf(conf);
1751 	return count;
1752 }
1753 
raid10_add_disk(struct mddev *mddev, struct md_rdev *rdev)1754 static int raid10_add_disk(struct mddev *mddev, struct md_rdev *rdev)
1755 {
1756 	struct r10conf *conf = mddev->private;
1757 	int err = -EEXIST;
1758 	int mirror;
1759 	int first = 0;
1760 	int last = conf->geo.raid_disks - 1;
1761 
1762 	if (mddev->recovery_cp < MaxSector)
1763 		/* only hot-add to in-sync arrays, as recovery is
1764 		 * very different from resync
1765 		 */
1766 		return -EBUSY;
1767 	if (rdev->saved_raid_disk < 0 && !_enough(conf, 1, -1))
1768 		return -EINVAL;
1769 
1770 	if (md_integrity_add_rdev(rdev, mddev))
1771 		return -ENXIO;
1772 
1773 	if (rdev->raid_disk >= 0)
1774 		first = last = rdev->raid_disk;
1775 
1776 	if (rdev->saved_raid_disk >= first &&
1777 	    rdev->saved_raid_disk < conf->geo.raid_disks &&
1778 	    conf->mirrors[rdev->saved_raid_disk].rdev == NULL)
1779 		mirror = rdev->saved_raid_disk;
1780 	else
1781 		mirror = first;
1782 	for ( ; mirror <= last ; mirror++) {
1783 		struct raid10_info *p = &conf->mirrors[mirror];
1784 		if (p->recovery_disabled == mddev->recovery_disabled)
1785 			continue;
1786 		if (p->rdev) {
1787 			if (!test_bit(WantReplacement, &p->rdev->flags) ||
1788 			    p->replacement != NULL)
1789 				continue;
1790 			clear_bit(In_sync, &rdev->flags);
1791 			set_bit(Replacement, &rdev->flags);
1792 			rdev->raid_disk = mirror;
1793 			err = 0;
1794 			if (mddev->gendisk)
1795 				disk_stack_limits(mddev->gendisk, rdev->bdev,
1796 						  rdev->data_offset << 9);
1797 			conf->fullsync = 1;
1798 			rcu_assign_pointer(p->replacement, rdev);
1799 			break;
1800 		}
1801 
1802 		if (mddev->gendisk)
1803 			disk_stack_limits(mddev->gendisk, rdev->bdev,
1804 					  rdev->data_offset << 9);
1805 
1806 		p->head_position = 0;
1807 		p->recovery_disabled = mddev->recovery_disabled - 1;
1808 		rdev->raid_disk = mirror;
1809 		err = 0;
1810 		if (rdev->saved_raid_disk != mirror)
1811 			conf->fullsync = 1;
1812 		rcu_assign_pointer(p->rdev, rdev);
1813 		break;
1814 	}
1815 	if (mddev->queue && blk_queue_discard(bdev_get_queue(rdev->bdev)))
1816 		blk_queue_flag_set(QUEUE_FLAG_DISCARD, mddev->queue);
1817 
1818 	print_conf(conf);
1819 	return err;
1820 }
1821 
raid10_remove_disk(struct mddev *mddev, struct md_rdev *rdev)1822 static int raid10_remove_disk(struct mddev *mddev, struct md_rdev *rdev)
1823 {
1824 	struct r10conf *conf = mddev->private;
1825 	int err = 0;
1826 	int number = rdev->raid_disk;
1827 	struct md_rdev **rdevp;
1828 	struct raid10_info *p;
1829 
1830 	print_conf(conf);
1831 	if (unlikely(number >= mddev->raid_disks))
1832 		return 0;
1833 	p = conf->mirrors + number;
1834 	if (rdev == p->rdev)
1835 		rdevp = &p->rdev;
1836 	else if (rdev == p->replacement)
1837 		rdevp = &p->replacement;
1838 	else
1839 		return 0;
1840 
1841 	if (test_bit(In_sync, &rdev->flags) ||
1842 	    atomic_read(&rdev->nr_pending)) {
1843 		err = -EBUSY;
1844 		goto abort;
1845 	}
1846 	/* Only remove non-faulty devices if recovery
1847 	 * is not possible.
1848 	 */
1849 	if (!test_bit(Faulty, &rdev->flags) &&
1850 	    mddev->recovery_disabled != p->recovery_disabled &&
1851 	    (!p->replacement || p->replacement == rdev) &&
1852 	    number < conf->geo.raid_disks &&
1853 	    enough(conf, -1)) {
1854 		err = -EBUSY;
1855 		goto abort;
1856 	}
1857 	*rdevp = NULL;
1858 	if (!test_bit(RemoveSynchronized, &rdev->flags)) {
1859 		synchronize_rcu();
1860 		if (atomic_read(&rdev->nr_pending)) {
1861 			/* lost the race, try later */
1862 			err = -EBUSY;
1863 			*rdevp = rdev;
1864 			goto abort;
1865 		}
1866 	}
1867 	if (p->replacement) {
1868 		/* We must have just cleared 'rdev' */
1869 		p->rdev = p->replacement;
1870 		clear_bit(Replacement, &p->replacement->flags);
1871 		smp_mb(); /* Make sure other CPUs may see both as identical
1872 			   * but will never see neither -- if they are careful.
1873 			   */
1874 		p->replacement = NULL;
1875 	}
1876 
1877 	clear_bit(WantReplacement, &rdev->flags);
1878 	err = md_integrity_register(mddev);
1879 
1880 abort:
1881 
1882 	print_conf(conf);
1883 	return err;
1884 }
1885 
__end_sync_read(struct r10bio *r10_bio, struct bio *bio, int d)1886 static void __end_sync_read(struct r10bio *r10_bio, struct bio *bio, int d)
1887 {
1888 	struct r10conf *conf = r10_bio->mddev->private;
1889 
1890 	if (!bio->bi_status)
1891 		set_bit(R10BIO_Uptodate, &r10_bio->state);
1892 	else
1893 		/* The write handler will notice the lack of
1894 		 * R10BIO_Uptodate and record any errors etc
1895 		 */
1896 		atomic_add(r10_bio->sectors,
1897 			   &conf->mirrors[d].rdev->corrected_errors);
1898 
1899 	/* for reconstruct, we always reschedule after a read.
1900 	 * for resync, only after all reads
1901 	 */
1902 	rdev_dec_pending(conf->mirrors[d].rdev, conf->mddev);
1903 	if (test_bit(R10BIO_IsRecover, &r10_bio->state) ||
1904 	    atomic_dec_and_test(&r10_bio->remaining)) {
1905 		/* we have read all the blocks,
1906 		 * do the comparison in process context in raid10d
1907 		 */
1908 		reschedule_retry(r10_bio);
1909 	}
1910 }
1911 
end_sync_read(struct bio *bio)1912 static void end_sync_read(struct bio *bio)
1913 {
1914 	struct r10bio *r10_bio = get_resync_r10bio(bio);
1915 	struct r10conf *conf = r10_bio->mddev->private;
1916 	int d = find_bio_disk(conf, r10_bio, bio, NULL, NULL);
1917 
1918 	__end_sync_read(r10_bio, bio, d);
1919 }
1920 
end_reshape_read(struct bio *bio)1921 static void end_reshape_read(struct bio *bio)
1922 {
1923 	/* reshape read bio isn't allocated from r10buf_pool */
1924 	struct r10bio *r10_bio = bio->bi_private;
1925 
1926 	__end_sync_read(r10_bio, bio, r10_bio->read_slot);
1927 }
1928 
end_sync_request(struct r10bio *r10_bio)1929 static void end_sync_request(struct r10bio *r10_bio)
1930 {
1931 	struct mddev *mddev = r10_bio->mddev;
1932 
1933 	while (atomic_dec_and_test(&r10_bio->remaining)) {
1934 		if (r10_bio->master_bio == NULL) {
1935 			/* the primary of several recovery bios */
1936 			sector_t s = r10_bio->sectors;
1937 			if (test_bit(R10BIO_MadeGood, &r10_bio->state) ||
1938 			    test_bit(R10BIO_WriteError, &r10_bio->state))
1939 				reschedule_retry(r10_bio);
1940 			else
1941 				put_buf(r10_bio);
1942 			md_done_sync(mddev, s, 1);
1943 			break;
1944 		} else {
1945 			struct r10bio *r10_bio2 = (struct r10bio *)r10_bio->master_bio;
1946 			if (test_bit(R10BIO_MadeGood, &r10_bio->state) ||
1947 			    test_bit(R10BIO_WriteError, &r10_bio->state))
1948 				reschedule_retry(r10_bio);
1949 			else
1950 				put_buf(r10_bio);
1951 			r10_bio = r10_bio2;
1952 		}
1953 	}
1954 }
1955 
end_sync_write(struct bio *bio)1956 static void end_sync_write(struct bio *bio)
1957 {
1958 	struct r10bio *r10_bio = get_resync_r10bio(bio);
1959 	struct mddev *mddev = r10_bio->mddev;
1960 	struct r10conf *conf = mddev->private;
1961 	int d;
1962 	sector_t first_bad;
1963 	int bad_sectors;
1964 	int slot;
1965 	int repl;
1966 	struct md_rdev *rdev = NULL;
1967 
1968 	d = find_bio_disk(conf, r10_bio, bio, &slot, &repl);
1969 	if (repl)
1970 		rdev = conf->mirrors[d].replacement;
1971 	else
1972 		rdev = conf->mirrors[d].rdev;
1973 
1974 	if (bio->bi_status) {
1975 		if (repl)
1976 			md_error(mddev, rdev);
1977 		else {
1978 			set_bit(WriteErrorSeen, &rdev->flags);
1979 			if (!test_and_set_bit(WantReplacement, &rdev->flags))
1980 				set_bit(MD_RECOVERY_NEEDED,
1981 					&rdev->mddev->recovery);
1982 			set_bit(R10BIO_WriteError, &r10_bio->state);
1983 		}
1984 	} else if (is_badblock(rdev,
1985 			     r10_bio->devs[slot].addr,
1986 			     r10_bio->sectors,
1987 			     &first_bad, &bad_sectors))
1988 		set_bit(R10BIO_MadeGood, &r10_bio->state);
1989 
1990 	rdev_dec_pending(rdev, mddev);
1991 
1992 	end_sync_request(r10_bio);
1993 }
1994 
1995 /*
1996  * Note: sync and recover and handled very differently for raid10
1997  * This code is for resync.
1998  * For resync, we read through virtual addresses and read all blocks.
1999  * If there is any error, we schedule a write.  The lowest numbered
2000  * drive is authoritative.
2001  * However requests come for physical address, so we need to map.
2002  * For every physical address there are raid_disks/copies virtual addresses,
2003  * which is always are least one, but is not necessarly an integer.
2004  * This means that a physical address can span multiple chunks, so we may
2005  * have to submit multiple io requests for a single sync request.
2006  */
2007 /*
2008  * We check if all blocks are in-sync and only write to blocks that
2009  * aren't in sync
2010  */
sync_request_write(struct mddev *mddev, struct r10bio *r10_bio)2011 static void sync_request_write(struct mddev *mddev, struct r10bio *r10_bio)
2012 {
2013 	struct r10conf *conf = mddev->private;
2014 	int i, first;
2015 	struct bio *tbio, *fbio;
2016 	int vcnt;
2017 	struct page **tpages, **fpages;
2018 
2019 	atomic_set(&r10_bio->remaining, 1);
2020 
2021 	/* find the first device with a block */
2022 	for (i=0; i<conf->copies; i++)
2023 		if (!r10_bio->devs[i].bio->bi_status)
2024 			break;
2025 
2026 	if (i == conf->copies)
2027 		goto done;
2028 
2029 	first = i;
2030 	fbio = r10_bio->devs[i].bio;
2031 	fbio->bi_iter.bi_size = r10_bio->sectors << 9;
2032 	fbio->bi_iter.bi_idx = 0;
2033 	fpages = get_resync_pages(fbio)->pages;
2034 
2035 	vcnt = (r10_bio->sectors + (PAGE_SIZE >> 9) - 1) >> (PAGE_SHIFT - 9);
2036 	/* now find blocks with errors */
2037 	for (i=0 ; i < conf->copies ; i++) {
2038 		int  j, d;
2039 		struct md_rdev *rdev;
2040 		struct resync_pages *rp;
2041 
2042 		tbio = r10_bio->devs[i].bio;
2043 
2044 		if (tbio->bi_end_io != end_sync_read)
2045 			continue;
2046 		if (i == first)
2047 			continue;
2048 
2049 		tpages = get_resync_pages(tbio)->pages;
2050 		d = r10_bio->devs[i].devnum;
2051 		rdev = conf->mirrors[d].rdev;
2052 		if (!r10_bio->devs[i].bio->bi_status) {
2053 			/* We know that the bi_io_vec layout is the same for
2054 			 * both 'first' and 'i', so we just compare them.
2055 			 * All vec entries are PAGE_SIZE;
2056 			 */
2057 			int sectors = r10_bio->sectors;
2058 			for (j = 0; j < vcnt; j++) {
2059 				int len = PAGE_SIZE;
2060 				if (sectors < (len / 512))
2061 					len = sectors * 512;
2062 				if (memcmp(page_address(fpages[j]),
2063 					   page_address(tpages[j]),
2064 					   len))
2065 					break;
2066 				sectors -= len/512;
2067 			}
2068 			if (j == vcnt)
2069 				continue;
2070 			atomic64_add(r10_bio->sectors, &mddev->resync_mismatches);
2071 			if (test_bit(MD_RECOVERY_CHECK, &mddev->recovery))
2072 				/* Don't fix anything. */
2073 				continue;
2074 		} else if (test_bit(FailFast, &rdev->flags)) {
2075 			/* Just give up on this device */
2076 			md_error(rdev->mddev, rdev);
2077 			continue;
2078 		}
2079 		/* Ok, we need to write this bio, either to correct an
2080 		 * inconsistency or to correct an unreadable block.
2081 		 * First we need to fixup bv_offset, bv_len and
2082 		 * bi_vecs, as the read request might have corrupted these
2083 		 */
2084 		rp = get_resync_pages(tbio);
2085 		bio_reset(tbio);
2086 
2087 		md_bio_reset_resync_pages(tbio, rp, fbio->bi_iter.bi_size);
2088 
2089 		rp->raid_bio = r10_bio;
2090 		tbio->bi_private = rp;
2091 		tbio->bi_iter.bi_sector = r10_bio->devs[i].addr;
2092 		tbio->bi_end_io = end_sync_write;
2093 		bio_set_op_attrs(tbio, REQ_OP_WRITE, 0);
2094 
2095 		bio_copy_data(tbio, fbio);
2096 
2097 		atomic_inc(&conf->mirrors[d].rdev->nr_pending);
2098 		atomic_inc(&r10_bio->remaining);
2099 		md_sync_acct(conf->mirrors[d].rdev->bdev, bio_sectors(tbio));
2100 
2101 		if (test_bit(FailFast, &conf->mirrors[d].rdev->flags))
2102 			tbio->bi_opf |= MD_FAILFAST;
2103 		tbio->bi_iter.bi_sector += conf->mirrors[d].rdev->data_offset;
2104 		bio_set_dev(tbio, conf->mirrors[d].rdev->bdev);
2105 		submit_bio_noacct(tbio);
2106 	}
2107 
2108 	/* Now write out to any replacement devices
2109 	 * that are active
2110 	 */
2111 	for (i = 0; i < conf->copies; i++) {
2112 		int d;
2113 
2114 		tbio = r10_bio->devs[i].repl_bio;
2115 		if (!tbio || !tbio->bi_end_io)
2116 			continue;
2117 		if (r10_bio->devs[i].bio->bi_end_io != end_sync_write
2118 		    && r10_bio->devs[i].bio != fbio)
2119 			bio_copy_data(tbio, fbio);
2120 		d = r10_bio->devs[i].devnum;
2121 		atomic_inc(&r10_bio->remaining);
2122 		md_sync_acct(conf->mirrors[d].replacement->bdev,
2123 			     bio_sectors(tbio));
2124 		submit_bio_noacct(tbio);
2125 	}
2126 
2127 done:
2128 	if (atomic_dec_and_test(&r10_bio->remaining)) {
2129 		md_done_sync(mddev, r10_bio->sectors, 1);
2130 		put_buf(r10_bio);
2131 	}
2132 }
2133 
2134 /*
2135  * Now for the recovery code.
2136  * Recovery happens across physical sectors.
2137  * We recover all non-is_sync drives by finding the virtual address of
2138  * each, and then choose a working drive that also has that virt address.
2139  * There is a separate r10_bio for each non-in_sync drive.
2140  * Only the first two slots are in use. The first for reading,
2141  * The second for writing.
2142  *
2143  */
fix_recovery_read_error(struct r10bio *r10_bio)2144 static void fix_recovery_read_error(struct r10bio *r10_bio)
2145 {
2146 	/* We got a read error during recovery.
2147 	 * We repeat the read in smaller page-sized sections.
2148 	 * If a read succeeds, write it to the new device or record
2149 	 * a bad block if we cannot.
2150 	 * If a read fails, record a bad block on both old and
2151 	 * new devices.
2152 	 */
2153 	struct mddev *mddev = r10_bio->mddev;
2154 	struct r10conf *conf = mddev->private;
2155 	struct bio *bio = r10_bio->devs[0].bio;
2156 	sector_t sect = 0;
2157 	int sectors = r10_bio->sectors;
2158 	int idx = 0;
2159 	int dr = r10_bio->devs[0].devnum;
2160 	int dw = r10_bio->devs[1].devnum;
2161 	struct page **pages = get_resync_pages(bio)->pages;
2162 
2163 	while (sectors) {
2164 		int s = sectors;
2165 		struct md_rdev *rdev;
2166 		sector_t addr;
2167 		int ok;
2168 
2169 		if (s > (PAGE_SIZE>>9))
2170 			s = PAGE_SIZE >> 9;
2171 
2172 		rdev = conf->mirrors[dr].rdev;
2173 		addr = r10_bio->devs[0].addr + sect,
2174 		ok = sync_page_io(rdev,
2175 				  addr,
2176 				  s << 9,
2177 				  pages[idx],
2178 				  REQ_OP_READ, 0, false);
2179 		if (ok) {
2180 			rdev = conf->mirrors[dw].rdev;
2181 			addr = r10_bio->devs[1].addr + sect;
2182 			ok = sync_page_io(rdev,
2183 					  addr,
2184 					  s << 9,
2185 					  pages[idx],
2186 					  REQ_OP_WRITE, 0, false);
2187 			if (!ok) {
2188 				set_bit(WriteErrorSeen, &rdev->flags);
2189 				if (!test_and_set_bit(WantReplacement,
2190 						      &rdev->flags))
2191 					set_bit(MD_RECOVERY_NEEDED,
2192 						&rdev->mddev->recovery);
2193 			}
2194 		}
2195 		if (!ok) {
2196 			/* We don't worry if we cannot set a bad block -
2197 			 * it really is bad so there is no loss in not
2198 			 * recording it yet
2199 			 */
2200 			rdev_set_badblocks(rdev, addr, s, 0);
2201 
2202 			if (rdev != conf->mirrors[dw].rdev) {
2203 				/* need bad block on destination too */
2204 				struct md_rdev *rdev2 = conf->mirrors[dw].rdev;
2205 				addr = r10_bio->devs[1].addr + sect;
2206 				ok = rdev_set_badblocks(rdev2, addr, s, 0);
2207 				if (!ok) {
2208 					/* just abort the recovery */
2209 					pr_notice("md/raid10:%s: recovery aborted due to read error\n",
2210 						  mdname(mddev));
2211 
2212 					conf->mirrors[dw].recovery_disabled
2213 						= mddev->recovery_disabled;
2214 					set_bit(MD_RECOVERY_INTR,
2215 						&mddev->recovery);
2216 					break;
2217 				}
2218 			}
2219 		}
2220 
2221 		sectors -= s;
2222 		sect += s;
2223 		idx++;
2224 	}
2225 }
2226 
recovery_request_write(struct mddev *mddev, struct r10bio *r10_bio)2227 static void recovery_request_write(struct mddev *mddev, struct r10bio *r10_bio)
2228 {
2229 	struct r10conf *conf = mddev->private;
2230 	int d;
2231 	struct bio *wbio = r10_bio->devs[1].bio;
2232 	struct bio *wbio2 = r10_bio->devs[1].repl_bio;
2233 
2234 	/* Need to test wbio2->bi_end_io before we call
2235 	 * submit_bio_noacct as if the former is NULL,
2236 	 * the latter is free to free wbio2.
2237 	 */
2238 	if (wbio2 && !wbio2->bi_end_io)
2239 		wbio2 = NULL;
2240 
2241 	if (!test_bit(R10BIO_Uptodate, &r10_bio->state)) {
2242 		fix_recovery_read_error(r10_bio);
2243 		if (wbio->bi_end_io)
2244 			end_sync_request(r10_bio);
2245 		if (wbio2)
2246 			end_sync_request(r10_bio);
2247 		return;
2248 	}
2249 
2250 	/*
2251 	 * share the pages with the first bio
2252 	 * and submit the write request
2253 	 */
2254 	d = r10_bio->devs[1].devnum;
2255 	if (wbio->bi_end_io) {
2256 		atomic_inc(&conf->mirrors[d].rdev->nr_pending);
2257 		md_sync_acct(conf->mirrors[d].rdev->bdev, bio_sectors(wbio));
2258 		submit_bio_noacct(wbio);
2259 	}
2260 	if (wbio2) {
2261 		atomic_inc(&conf->mirrors[d].replacement->nr_pending);
2262 		md_sync_acct(conf->mirrors[d].replacement->bdev,
2263 			     bio_sectors(wbio2));
2264 		submit_bio_noacct(wbio2);
2265 	}
2266 }
2267 
2268 /*
2269  * Used by fix_read_error() to decay the per rdev read_errors.
2270  * We halve the read error count for every hour that has elapsed
2271  * since the last recorded read error.
2272  *
2273  */
check_decay_read_errors(struct mddev *mddev, struct md_rdev *rdev)2274 static void check_decay_read_errors(struct mddev *mddev, struct md_rdev *rdev)
2275 {
2276 	long cur_time_mon;
2277 	unsigned long hours_since_last;
2278 	unsigned int read_errors = atomic_read(&rdev->read_errors);
2279 
2280 	cur_time_mon = ktime_get_seconds();
2281 
2282 	if (rdev->last_read_error == 0) {
2283 		/* first time we've seen a read error */
2284 		rdev->last_read_error = cur_time_mon;
2285 		return;
2286 	}
2287 
2288 	hours_since_last = (long)(cur_time_mon -
2289 			    rdev->last_read_error) / 3600;
2290 
2291 	rdev->last_read_error = cur_time_mon;
2292 
2293 	/*
2294 	 * if hours_since_last is > the number of bits in read_errors
2295 	 * just set read errors to 0. We do this to avoid
2296 	 * overflowing the shift of read_errors by hours_since_last.
2297 	 */
2298 	if (hours_since_last >= 8 * sizeof(read_errors))
2299 		atomic_set(&rdev->read_errors, 0);
2300 	else
2301 		atomic_set(&rdev->read_errors, read_errors >> hours_since_last);
2302 }
2303 
r10_sync_page_io(struct md_rdev *rdev, sector_t sector, int sectors, struct page *page, int rw)2304 static int r10_sync_page_io(struct md_rdev *rdev, sector_t sector,
2305 			    int sectors, struct page *page, int rw)
2306 {
2307 	sector_t first_bad;
2308 	int bad_sectors;
2309 
2310 	if (is_badblock(rdev, sector, sectors, &first_bad, &bad_sectors)
2311 	    && (rw == READ || test_bit(WriteErrorSeen, &rdev->flags)))
2312 		return -1;
2313 	if (sync_page_io(rdev, sector, sectors << 9, page, rw, 0, false))
2314 		/* success */
2315 		return 1;
2316 	if (rw == WRITE) {
2317 		set_bit(WriteErrorSeen, &rdev->flags);
2318 		if (!test_and_set_bit(WantReplacement, &rdev->flags))
2319 			set_bit(MD_RECOVERY_NEEDED,
2320 				&rdev->mddev->recovery);
2321 	}
2322 	/* need to record an error - either for the block or the device */
2323 	if (!rdev_set_badblocks(rdev, sector, sectors, 0))
2324 		md_error(rdev->mddev, rdev);
2325 	return 0;
2326 }
2327 
2328 /*
2329  * This is a kernel thread which:
2330  *
2331  *	1.	Retries failed read operations on working mirrors.
2332  *	2.	Updates the raid superblock when problems encounter.
2333  *	3.	Performs writes following reads for array synchronising.
2334  */
2335 
fix_read_error(struct r10conf *conf, struct mddev *mddev, struct r10bio *r10_bio)2336 static void fix_read_error(struct r10conf *conf, struct mddev *mddev, struct r10bio *r10_bio)
2337 {
2338 	int sect = 0; /* Offset from r10_bio->sector */
2339 	int sectors = r10_bio->sectors;
2340 	struct md_rdev *rdev;
2341 	int max_read_errors = atomic_read(&mddev->max_corr_read_errors);
2342 	int d = r10_bio->devs[r10_bio->read_slot].devnum;
2343 
2344 	/* still own a reference to this rdev, so it cannot
2345 	 * have been cleared recently.
2346 	 */
2347 	rdev = conf->mirrors[d].rdev;
2348 
2349 	if (test_bit(Faulty, &rdev->flags))
2350 		/* drive has already been failed, just ignore any
2351 		   more fix_read_error() attempts */
2352 		return;
2353 
2354 	check_decay_read_errors(mddev, rdev);
2355 	atomic_inc(&rdev->read_errors);
2356 	if (atomic_read(&rdev->read_errors) > max_read_errors) {
2357 		char b[BDEVNAME_SIZE];
2358 		bdevname(rdev->bdev, b);
2359 
2360 		pr_notice("md/raid10:%s: %s: Raid device exceeded read_error threshold [cur %d:max %d]\n",
2361 			  mdname(mddev), b,
2362 			  atomic_read(&rdev->read_errors), max_read_errors);
2363 		pr_notice("md/raid10:%s: %s: Failing raid device\n",
2364 			  mdname(mddev), b);
2365 		md_error(mddev, rdev);
2366 		r10_bio->devs[r10_bio->read_slot].bio = IO_BLOCKED;
2367 		return;
2368 	}
2369 
2370 	while(sectors) {
2371 		int s = sectors;
2372 		int sl = r10_bio->read_slot;
2373 		int success = 0;
2374 		int start;
2375 
2376 		if (s > (PAGE_SIZE>>9))
2377 			s = PAGE_SIZE >> 9;
2378 
2379 		rcu_read_lock();
2380 		do {
2381 			sector_t first_bad;
2382 			int bad_sectors;
2383 
2384 			d = r10_bio->devs[sl].devnum;
2385 			rdev = rcu_dereference(conf->mirrors[d].rdev);
2386 			if (rdev &&
2387 			    test_bit(In_sync, &rdev->flags) &&
2388 			    !test_bit(Faulty, &rdev->flags) &&
2389 			    is_badblock(rdev, r10_bio->devs[sl].addr + sect, s,
2390 					&first_bad, &bad_sectors) == 0) {
2391 				atomic_inc(&rdev->nr_pending);
2392 				rcu_read_unlock();
2393 				success = sync_page_io(rdev,
2394 						       r10_bio->devs[sl].addr +
2395 						       sect,
2396 						       s<<9,
2397 						       conf->tmppage,
2398 						       REQ_OP_READ, 0, false);
2399 				rdev_dec_pending(rdev, mddev);
2400 				rcu_read_lock();
2401 				if (success)
2402 					break;
2403 			}
2404 			sl++;
2405 			if (sl == conf->copies)
2406 				sl = 0;
2407 		} while (!success && sl != r10_bio->read_slot);
2408 		rcu_read_unlock();
2409 
2410 		if (!success) {
2411 			/* Cannot read from anywhere, just mark the block
2412 			 * as bad on the first device to discourage future
2413 			 * reads.
2414 			 */
2415 			int dn = r10_bio->devs[r10_bio->read_slot].devnum;
2416 			rdev = conf->mirrors[dn].rdev;
2417 
2418 			if (!rdev_set_badblocks(
2419 				    rdev,
2420 				    r10_bio->devs[r10_bio->read_slot].addr
2421 				    + sect,
2422 				    s, 0)) {
2423 				md_error(mddev, rdev);
2424 				r10_bio->devs[r10_bio->read_slot].bio
2425 					= IO_BLOCKED;
2426 			}
2427 			break;
2428 		}
2429 
2430 		start = sl;
2431 		/* write it back and re-read */
2432 		rcu_read_lock();
2433 		while (sl != r10_bio->read_slot) {
2434 			char b[BDEVNAME_SIZE];
2435 
2436 			if (sl==0)
2437 				sl = conf->copies;
2438 			sl--;
2439 			d = r10_bio->devs[sl].devnum;
2440 			rdev = rcu_dereference(conf->mirrors[d].rdev);
2441 			if (!rdev ||
2442 			    test_bit(Faulty, &rdev->flags) ||
2443 			    !test_bit(In_sync, &rdev->flags))
2444 				continue;
2445 
2446 			atomic_inc(&rdev->nr_pending);
2447 			rcu_read_unlock();
2448 			if (r10_sync_page_io(rdev,
2449 					     r10_bio->devs[sl].addr +
2450 					     sect,
2451 					     s, conf->tmppage, WRITE)
2452 			    == 0) {
2453 				/* Well, this device is dead */
2454 				pr_notice("md/raid10:%s: read correction write failed (%d sectors at %llu on %s)\n",
2455 					  mdname(mddev), s,
2456 					  (unsigned long long)(
2457 						  sect +
2458 						  choose_data_offset(r10_bio,
2459 								     rdev)),
2460 					  bdevname(rdev->bdev, b));
2461 				pr_notice("md/raid10:%s: %s: failing drive\n",
2462 					  mdname(mddev),
2463 					  bdevname(rdev->bdev, b));
2464 			}
2465 			rdev_dec_pending(rdev, mddev);
2466 			rcu_read_lock();
2467 		}
2468 		sl = start;
2469 		while (sl != r10_bio->read_slot) {
2470 			char b[BDEVNAME_SIZE];
2471 
2472 			if (sl==0)
2473 				sl = conf->copies;
2474 			sl--;
2475 			d = r10_bio->devs[sl].devnum;
2476 			rdev = rcu_dereference(conf->mirrors[d].rdev);
2477 			if (!rdev ||
2478 			    test_bit(Faulty, &rdev->flags) ||
2479 			    !test_bit(In_sync, &rdev->flags))
2480 				continue;
2481 
2482 			atomic_inc(&rdev->nr_pending);
2483 			rcu_read_unlock();
2484 			switch (r10_sync_page_io(rdev,
2485 					     r10_bio->devs[sl].addr +
2486 					     sect,
2487 					     s, conf->tmppage,
2488 						 READ)) {
2489 			case 0:
2490 				/* Well, this device is dead */
2491 				pr_notice("md/raid10:%s: unable to read back corrected sectors (%d sectors at %llu on %s)\n",
2492 				       mdname(mddev), s,
2493 				       (unsigned long long)(
2494 					       sect +
2495 					       choose_data_offset(r10_bio, rdev)),
2496 				       bdevname(rdev->bdev, b));
2497 				pr_notice("md/raid10:%s: %s: failing drive\n",
2498 				       mdname(mddev),
2499 				       bdevname(rdev->bdev, b));
2500 				break;
2501 			case 1:
2502 				pr_info("md/raid10:%s: read error corrected (%d sectors at %llu on %s)\n",
2503 				       mdname(mddev), s,
2504 				       (unsigned long long)(
2505 					       sect +
2506 					       choose_data_offset(r10_bio, rdev)),
2507 				       bdevname(rdev->bdev, b));
2508 				atomic_add(s, &rdev->corrected_errors);
2509 			}
2510 
2511 			rdev_dec_pending(rdev, mddev);
2512 			rcu_read_lock();
2513 		}
2514 		rcu_read_unlock();
2515 
2516 		sectors -= s;
2517 		sect += s;
2518 	}
2519 }
2520 
narrow_write_error(struct r10bio *r10_bio, int i)2521 static int narrow_write_error(struct r10bio *r10_bio, int i)
2522 {
2523 	struct bio *bio = r10_bio->master_bio;
2524 	struct mddev *mddev = r10_bio->mddev;
2525 	struct r10conf *conf = mddev->private;
2526 	struct md_rdev *rdev = conf->mirrors[r10_bio->devs[i].devnum].rdev;
2527 	/* bio has the data to be written to slot 'i' where
2528 	 * we just recently had a write error.
2529 	 * We repeatedly clone the bio and trim down to one block,
2530 	 * then try the write.  Where the write fails we record
2531 	 * a bad block.
2532 	 * It is conceivable that the bio doesn't exactly align with
2533 	 * blocks.  We must handle this.
2534 	 *
2535 	 * We currently own a reference to the rdev.
2536 	 */
2537 
2538 	int block_sectors;
2539 	sector_t sector;
2540 	int sectors;
2541 	int sect_to_write = r10_bio->sectors;
2542 	int ok = 1;
2543 
2544 	if (rdev->badblocks.shift < 0)
2545 		return 0;
2546 
2547 	block_sectors = roundup(1 << rdev->badblocks.shift,
2548 				bdev_logical_block_size(rdev->bdev) >> 9);
2549 	sector = r10_bio->sector;
2550 	sectors = ((r10_bio->sector + block_sectors)
2551 		   & ~(sector_t)(block_sectors - 1))
2552 		- sector;
2553 
2554 	while (sect_to_write) {
2555 		struct bio *wbio;
2556 		sector_t wsector;
2557 		if (sectors > sect_to_write)
2558 			sectors = sect_to_write;
2559 		/* Write at 'sector' for 'sectors' */
2560 		wbio = bio_clone_fast(bio, GFP_NOIO, &mddev->bio_set);
2561 		bio_trim(wbio, sector - bio->bi_iter.bi_sector, sectors);
2562 		wsector = r10_bio->devs[i].addr + (sector - r10_bio->sector);
2563 		wbio->bi_iter.bi_sector = wsector +
2564 				   choose_data_offset(r10_bio, rdev);
2565 		bio_set_dev(wbio, rdev->bdev);
2566 		bio_set_op_attrs(wbio, REQ_OP_WRITE, 0);
2567 
2568 		if (submit_bio_wait(wbio) < 0)
2569 			/* Failure! */
2570 			ok = rdev_set_badblocks(rdev, wsector,
2571 						sectors, 0)
2572 				&& ok;
2573 
2574 		bio_put(wbio);
2575 		sect_to_write -= sectors;
2576 		sector += sectors;
2577 		sectors = block_sectors;
2578 	}
2579 	return ok;
2580 }
2581 
handle_read_error(struct mddev *mddev, struct r10bio *r10_bio)2582 static void handle_read_error(struct mddev *mddev, struct r10bio *r10_bio)
2583 {
2584 	int slot = r10_bio->read_slot;
2585 	struct bio *bio;
2586 	struct r10conf *conf = mddev->private;
2587 	struct md_rdev *rdev = r10_bio->devs[slot].rdev;
2588 
2589 	/* we got a read error. Maybe the drive is bad.  Maybe just
2590 	 * the block and we can fix it.
2591 	 * We freeze all other IO, and try reading the block from
2592 	 * other devices.  When we find one, we re-write
2593 	 * and check it that fixes the read error.
2594 	 * This is all done synchronously while the array is
2595 	 * frozen.
2596 	 */
2597 	bio = r10_bio->devs[slot].bio;
2598 	bio_put(bio);
2599 	r10_bio->devs[slot].bio = NULL;
2600 
2601 	if (mddev->ro)
2602 		r10_bio->devs[slot].bio = IO_BLOCKED;
2603 	else if (!test_bit(FailFast, &rdev->flags)) {
2604 		freeze_array(conf, 1);
2605 		fix_read_error(conf, mddev, r10_bio);
2606 		unfreeze_array(conf);
2607 	} else
2608 		md_error(mddev, rdev);
2609 
2610 	rdev_dec_pending(rdev, mddev);
2611 	allow_barrier(conf);
2612 	r10_bio->state = 0;
2613 	raid10_read_request(mddev, r10_bio->master_bio, r10_bio);
2614 }
2615 
handle_write_completed(struct r10conf *conf, struct r10bio *r10_bio)2616 static void handle_write_completed(struct r10conf *conf, struct r10bio *r10_bio)
2617 {
2618 	/* Some sort of write request has finished and it
2619 	 * succeeded in writing where we thought there was a
2620 	 * bad block.  So forget the bad block.
2621 	 * Or possibly if failed and we need to record
2622 	 * a bad block.
2623 	 */
2624 	int m;
2625 	struct md_rdev *rdev;
2626 
2627 	if (test_bit(R10BIO_IsSync, &r10_bio->state) ||
2628 	    test_bit(R10BIO_IsRecover, &r10_bio->state)) {
2629 		for (m = 0; m < conf->copies; m++) {
2630 			int dev = r10_bio->devs[m].devnum;
2631 			rdev = conf->mirrors[dev].rdev;
2632 			if (r10_bio->devs[m].bio == NULL ||
2633 				r10_bio->devs[m].bio->bi_end_io == NULL)
2634 				continue;
2635 			if (!r10_bio->devs[m].bio->bi_status) {
2636 				rdev_clear_badblocks(
2637 					rdev,
2638 					r10_bio->devs[m].addr,
2639 					r10_bio->sectors, 0);
2640 			} else {
2641 				if (!rdev_set_badblocks(
2642 					    rdev,
2643 					    r10_bio->devs[m].addr,
2644 					    r10_bio->sectors, 0))
2645 					md_error(conf->mddev, rdev);
2646 			}
2647 			rdev = conf->mirrors[dev].replacement;
2648 			if (r10_bio->devs[m].repl_bio == NULL ||
2649 				r10_bio->devs[m].repl_bio->bi_end_io == NULL)
2650 				continue;
2651 
2652 			if (!r10_bio->devs[m].repl_bio->bi_status) {
2653 				rdev_clear_badblocks(
2654 					rdev,
2655 					r10_bio->devs[m].addr,
2656 					r10_bio->sectors, 0);
2657 			} else {
2658 				if (!rdev_set_badblocks(
2659 					    rdev,
2660 					    r10_bio->devs[m].addr,
2661 					    r10_bio->sectors, 0))
2662 					md_error(conf->mddev, rdev);
2663 			}
2664 		}
2665 		put_buf(r10_bio);
2666 	} else {
2667 		bool fail = false;
2668 		for (m = 0; m < conf->copies; m++) {
2669 			int dev = r10_bio->devs[m].devnum;
2670 			struct bio *bio = r10_bio->devs[m].bio;
2671 			rdev = conf->mirrors[dev].rdev;
2672 			if (bio == IO_MADE_GOOD) {
2673 				rdev_clear_badblocks(
2674 					rdev,
2675 					r10_bio->devs[m].addr,
2676 					r10_bio->sectors, 0);
2677 				rdev_dec_pending(rdev, conf->mddev);
2678 			} else if (bio != NULL && bio->bi_status) {
2679 				fail = true;
2680 				if (!narrow_write_error(r10_bio, m)) {
2681 					md_error(conf->mddev, rdev);
2682 					set_bit(R10BIO_Degraded,
2683 						&r10_bio->state);
2684 				}
2685 				rdev_dec_pending(rdev, conf->mddev);
2686 			}
2687 			bio = r10_bio->devs[m].repl_bio;
2688 			rdev = conf->mirrors[dev].replacement;
2689 			if (rdev && bio == IO_MADE_GOOD) {
2690 				rdev_clear_badblocks(
2691 					rdev,
2692 					r10_bio->devs[m].addr,
2693 					r10_bio->sectors, 0);
2694 				rdev_dec_pending(rdev, conf->mddev);
2695 			}
2696 		}
2697 		if (fail) {
2698 			spin_lock_irq(&conf->device_lock);
2699 			list_add(&r10_bio->retry_list, &conf->bio_end_io_list);
2700 			conf->nr_queued++;
2701 			spin_unlock_irq(&conf->device_lock);
2702 			/*
2703 			 * In case freeze_array() is waiting for condition
2704 			 * nr_pending == nr_queued + extra to be true.
2705 			 */
2706 			wake_up(&conf->wait_barrier);
2707 			md_wakeup_thread(conf->mddev->thread);
2708 		} else {
2709 			if (test_bit(R10BIO_WriteError,
2710 				     &r10_bio->state))
2711 				close_write(r10_bio);
2712 			raid_end_bio_io(r10_bio);
2713 		}
2714 	}
2715 }
2716 
raid10d(struct md_thread *thread)2717 static void raid10d(struct md_thread *thread)
2718 {
2719 	struct mddev *mddev = thread->mddev;
2720 	struct r10bio *r10_bio;
2721 	unsigned long flags;
2722 	struct r10conf *conf = mddev->private;
2723 	struct list_head *head = &conf->retry_list;
2724 	struct blk_plug plug;
2725 
2726 	md_check_recovery(mddev);
2727 
2728 	if (!list_empty_careful(&conf->bio_end_io_list) &&
2729 	    !test_bit(MD_SB_CHANGE_PENDING, &mddev->sb_flags)) {
2730 		LIST_HEAD(tmp);
2731 		spin_lock_irqsave(&conf->device_lock, flags);
2732 		if (!test_bit(MD_SB_CHANGE_PENDING, &mddev->sb_flags)) {
2733 			while (!list_empty(&conf->bio_end_io_list)) {
2734 				list_move(conf->bio_end_io_list.prev, &tmp);
2735 				conf->nr_queued--;
2736 			}
2737 		}
2738 		spin_unlock_irqrestore(&conf->device_lock, flags);
2739 		while (!list_empty(&tmp)) {
2740 			r10_bio = list_first_entry(&tmp, struct r10bio,
2741 						   retry_list);
2742 			list_del(&r10_bio->retry_list);
2743 			if (mddev->degraded)
2744 				set_bit(R10BIO_Degraded, &r10_bio->state);
2745 
2746 			if (test_bit(R10BIO_WriteError,
2747 				     &r10_bio->state))
2748 				close_write(r10_bio);
2749 			raid_end_bio_io(r10_bio);
2750 		}
2751 	}
2752 
2753 	blk_start_plug(&plug);
2754 	for (;;) {
2755 
2756 		flush_pending_writes(conf);
2757 
2758 		spin_lock_irqsave(&conf->device_lock, flags);
2759 		if (list_empty(head)) {
2760 			spin_unlock_irqrestore(&conf->device_lock, flags);
2761 			break;
2762 		}
2763 		r10_bio = list_entry(head->prev, struct r10bio, retry_list);
2764 		list_del(head->prev);
2765 		conf->nr_queued--;
2766 		spin_unlock_irqrestore(&conf->device_lock, flags);
2767 
2768 		mddev = r10_bio->mddev;
2769 		conf = mddev->private;
2770 		if (test_bit(R10BIO_MadeGood, &r10_bio->state) ||
2771 		    test_bit(R10BIO_WriteError, &r10_bio->state))
2772 			handle_write_completed(conf, r10_bio);
2773 		else if (test_bit(R10BIO_IsReshape, &r10_bio->state))
2774 			reshape_request_write(mddev, r10_bio);
2775 		else if (test_bit(R10BIO_IsSync, &r10_bio->state))
2776 			sync_request_write(mddev, r10_bio);
2777 		else if (test_bit(R10BIO_IsRecover, &r10_bio->state))
2778 			recovery_request_write(mddev, r10_bio);
2779 		else if (test_bit(R10BIO_ReadError, &r10_bio->state))
2780 			handle_read_error(mddev, r10_bio);
2781 		else
2782 			WARN_ON_ONCE(1);
2783 
2784 		cond_resched();
2785 		if (mddev->sb_flags & ~(1<<MD_SB_CHANGE_PENDING))
2786 			md_check_recovery(mddev);
2787 	}
2788 	blk_finish_plug(&plug);
2789 }
2790 
init_resync(struct r10conf *conf)2791 static int init_resync(struct r10conf *conf)
2792 {
2793 	int ret, buffs, i;
2794 
2795 	buffs = RESYNC_WINDOW / RESYNC_BLOCK_SIZE;
2796 	BUG_ON(mempool_initialized(&conf->r10buf_pool));
2797 	conf->have_replacement = 0;
2798 	for (i = 0; i < conf->geo.raid_disks; i++)
2799 		if (conf->mirrors[i].replacement)
2800 			conf->have_replacement = 1;
2801 	ret = mempool_init(&conf->r10buf_pool, buffs,
2802 			   r10buf_pool_alloc, r10buf_pool_free, conf);
2803 	if (ret)
2804 		return ret;
2805 	conf->next_resync = 0;
2806 	return 0;
2807 }
2808 
raid10_alloc_init_r10buf(struct r10conf *conf)2809 static struct r10bio *raid10_alloc_init_r10buf(struct r10conf *conf)
2810 {
2811 	struct r10bio *r10bio = mempool_alloc(&conf->r10buf_pool, GFP_NOIO);
2812 	struct rsync_pages *rp;
2813 	struct bio *bio;
2814 	int nalloc;
2815 	int i;
2816 
2817 	if (test_bit(MD_RECOVERY_SYNC, &conf->mddev->recovery) ||
2818 	    test_bit(MD_RECOVERY_RESHAPE, &conf->mddev->recovery))
2819 		nalloc = conf->copies; /* resync */
2820 	else
2821 		nalloc = 2; /* recovery */
2822 
2823 	for (i = 0; i < nalloc; i++) {
2824 		bio = r10bio->devs[i].bio;
2825 		rp = bio->bi_private;
2826 		bio_reset(bio);
2827 		bio->bi_private = rp;
2828 		bio = r10bio->devs[i].repl_bio;
2829 		if (bio) {
2830 			rp = bio->bi_private;
2831 			bio_reset(bio);
2832 			bio->bi_private = rp;
2833 		}
2834 	}
2835 	return r10bio;
2836 }
2837 
2838 /*
2839  * Set cluster_sync_high since we need other nodes to add the
2840  * range [cluster_sync_low, cluster_sync_high] to suspend list.
2841  */
raid10_set_cluster_sync_high(struct r10conf *conf)2842 static void raid10_set_cluster_sync_high(struct r10conf *conf)
2843 {
2844 	sector_t window_size;
2845 	int extra_chunk, chunks;
2846 
2847 	/*
2848 	 * First, here we define "stripe" as a unit which across
2849 	 * all member devices one time, so we get chunks by use
2850 	 * raid_disks / near_copies. Otherwise, if near_copies is
2851 	 * close to raid_disks, then resync window could increases
2852 	 * linearly with the increase of raid_disks, which means
2853 	 * we will suspend a really large IO window while it is not
2854 	 * necessary. If raid_disks is not divisible by near_copies,
2855 	 * an extra chunk is needed to ensure the whole "stripe" is
2856 	 * covered.
2857 	 */
2858 
2859 	chunks = conf->geo.raid_disks / conf->geo.near_copies;
2860 	if (conf->geo.raid_disks % conf->geo.near_copies == 0)
2861 		extra_chunk = 0;
2862 	else
2863 		extra_chunk = 1;
2864 	window_size = (chunks + extra_chunk) * conf->mddev->chunk_sectors;
2865 
2866 	/*
2867 	 * At least use a 32M window to align with raid1's resync window
2868 	 */
2869 	window_size = (CLUSTER_RESYNC_WINDOW_SECTORS > window_size) ?
2870 			CLUSTER_RESYNC_WINDOW_SECTORS : window_size;
2871 
2872 	conf->cluster_sync_high = conf->cluster_sync_low + window_size;
2873 }
2874 
2875 /*
2876  * perform a "sync" on one "block"
2877  *
2878  * We need to make sure that no normal I/O request - particularly write
2879  * requests - conflict with active sync requests.
2880  *
2881  * This is achieved by tracking pending requests and a 'barrier' concept
2882  * that can be installed to exclude normal IO requests.
2883  *
2884  * Resync and recovery are handled very differently.
2885  * We differentiate by looking at MD_RECOVERY_SYNC in mddev->recovery.
2886  *
2887  * For resync, we iterate over virtual addresses, read all copies,
2888  * and update if there are differences.  If only one copy is live,
2889  * skip it.
2890  * For recovery, we iterate over physical addresses, read a good
2891  * value for each non-in_sync drive, and over-write.
2892  *
2893  * So, for recovery we may have several outstanding complex requests for a
2894  * given address, one for each out-of-sync device.  We model this by allocating
2895  * a number of r10_bio structures, one for each out-of-sync device.
2896  * As we setup these structures, we collect all bio's together into a list
2897  * which we then process collectively to add pages, and then process again
2898  * to pass to submit_bio_noacct.
2899  *
2900  * The r10_bio structures are linked using a borrowed master_bio pointer.
2901  * This link is counted in ->remaining.  When the r10_bio that points to NULL
2902  * has its remaining count decremented to 0, the whole complex operation
2903  * is complete.
2904  *
2905  */
2906 
raid10_sync_request(struct mddev *mddev, sector_t sector_nr, int *skipped)2907 static sector_t raid10_sync_request(struct mddev *mddev, sector_t sector_nr,
2908 			     int *skipped)
2909 {
2910 	struct r10conf *conf = mddev->private;
2911 	struct r10bio *r10_bio;
2912 	struct bio *biolist = NULL, *bio;
2913 	sector_t max_sector, nr_sectors;
2914 	int i;
2915 	int max_sync;
2916 	sector_t sync_blocks;
2917 	sector_t sectors_skipped = 0;
2918 	int chunks_skipped = 0;
2919 	sector_t chunk_mask = conf->geo.chunk_mask;
2920 	int page_idx = 0;
2921 
2922 	/*
2923 	 * Allow skipping a full rebuild for incremental assembly
2924 	 * of a clean array, like RAID1 does.
2925 	 */
2926 	if (mddev->bitmap == NULL &&
2927 	    mddev->recovery_cp == MaxSector &&
2928 	    mddev->reshape_position == MaxSector &&
2929 	    !test_bit(MD_RECOVERY_SYNC, &mddev->recovery) &&
2930 	    !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery) &&
2931 	    !test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery) &&
2932 	    conf->fullsync == 0) {
2933 		*skipped = 1;
2934 		return mddev->dev_sectors - sector_nr;
2935 	}
2936 
2937 	if (!mempool_initialized(&conf->r10buf_pool))
2938 		if (init_resync(conf))
2939 			return 0;
2940 
2941  skipped:
2942 	max_sector = mddev->dev_sectors;
2943 	if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery) ||
2944 	    test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery))
2945 		max_sector = mddev->resync_max_sectors;
2946 	if (sector_nr >= max_sector) {
2947 		conf->cluster_sync_low = 0;
2948 		conf->cluster_sync_high = 0;
2949 
2950 		/* If we aborted, we need to abort the
2951 		 * sync on the 'current' bitmap chucks (there can
2952 		 * be several when recovering multiple devices).
2953 		 * as we may have started syncing it but not finished.
2954 		 * We can find the current address in
2955 		 * mddev->curr_resync, but for recovery,
2956 		 * we need to convert that to several
2957 		 * virtual addresses.
2958 		 */
2959 		if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery)) {
2960 			end_reshape(conf);
2961 			close_sync(conf);
2962 			return 0;
2963 		}
2964 
2965 		if (mddev->curr_resync < max_sector) { /* aborted */
2966 			if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery))
2967 				md_bitmap_end_sync(mddev->bitmap, mddev->curr_resync,
2968 						   &sync_blocks, 1);
2969 			else for (i = 0; i < conf->geo.raid_disks; i++) {
2970 				sector_t sect =
2971 					raid10_find_virt(conf, mddev->curr_resync, i);
2972 				md_bitmap_end_sync(mddev->bitmap, sect,
2973 						   &sync_blocks, 1);
2974 			}
2975 		} else {
2976 			/* completed sync */
2977 			if ((!mddev->bitmap || conf->fullsync)
2978 			    && conf->have_replacement
2979 			    && test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) {
2980 				/* Completed a full sync so the replacements
2981 				 * are now fully recovered.
2982 				 */
2983 				rcu_read_lock();
2984 				for (i = 0; i < conf->geo.raid_disks; i++) {
2985 					struct md_rdev *rdev =
2986 						rcu_dereference(conf->mirrors[i].replacement);
2987 					if (rdev)
2988 						rdev->recovery_offset = MaxSector;
2989 				}
2990 				rcu_read_unlock();
2991 			}
2992 			conf->fullsync = 0;
2993 		}
2994 		md_bitmap_close_sync(mddev->bitmap);
2995 		close_sync(conf);
2996 		*skipped = 1;
2997 		return sectors_skipped;
2998 	}
2999 
3000 	if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery))
3001 		return reshape_request(mddev, sector_nr, skipped);
3002 
3003 	if (chunks_skipped >= conf->geo.raid_disks) {
3004 		/* if there has been nothing to do on any drive,
3005 		 * then there is nothing to do at all..
3006 		 */
3007 		*skipped = 1;
3008 		return (max_sector - sector_nr) + sectors_skipped;
3009 	}
3010 
3011 	if (max_sector > mddev->resync_max)
3012 		max_sector = mddev->resync_max; /* Don't do IO beyond here */
3013 
3014 	/* make sure whole request will fit in a chunk - if chunks
3015 	 * are meaningful
3016 	 */
3017 	if (conf->geo.near_copies < conf->geo.raid_disks &&
3018 	    max_sector > (sector_nr | chunk_mask))
3019 		max_sector = (sector_nr | chunk_mask) + 1;
3020 
3021 	/*
3022 	 * If there is non-resync activity waiting for a turn, then let it
3023 	 * though before starting on this new sync request.
3024 	 */
3025 	if (conf->nr_waiting)
3026 		schedule_timeout_uninterruptible(1);
3027 
3028 	/* Again, very different code for resync and recovery.
3029 	 * Both must result in an r10bio with a list of bios that
3030 	 * have bi_end_io, bi_sector, bi_disk set,
3031 	 * and bi_private set to the r10bio.
3032 	 * For recovery, we may actually create several r10bios
3033 	 * with 2 bios in each, that correspond to the bios in the main one.
3034 	 * In this case, the subordinate r10bios link back through a
3035 	 * borrowed master_bio pointer, and the counter in the master
3036 	 * includes a ref from each subordinate.
3037 	 */
3038 	/* First, we decide what to do and set ->bi_end_io
3039 	 * To end_sync_read if we want to read, and
3040 	 * end_sync_write if we will want to write.
3041 	 */
3042 
3043 	max_sync = RESYNC_PAGES << (PAGE_SHIFT-9);
3044 	if (!test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) {
3045 		/* recovery... the complicated one */
3046 		int j;
3047 		r10_bio = NULL;
3048 
3049 		for (i = 0 ; i < conf->geo.raid_disks; i++) {
3050 			int still_degraded;
3051 			struct r10bio *rb2;
3052 			sector_t sect;
3053 			int must_sync;
3054 			int any_working;
3055 			int need_recover = 0;
3056 			struct raid10_info *mirror = &conf->mirrors[i];
3057 			struct md_rdev *mrdev, *mreplace;
3058 
3059 			rcu_read_lock();
3060 			mrdev = rcu_dereference(mirror->rdev);
3061 			mreplace = rcu_dereference(mirror->replacement);
3062 
3063 			if (mrdev != NULL &&
3064 			    !test_bit(Faulty, &mrdev->flags) &&
3065 			    !test_bit(In_sync, &mrdev->flags))
3066 				need_recover = 1;
3067 			if (mreplace && test_bit(Faulty, &mreplace->flags))
3068 				mreplace = NULL;
3069 
3070 			if (!need_recover && !mreplace) {
3071 				rcu_read_unlock();
3072 				continue;
3073 			}
3074 
3075 			still_degraded = 0;
3076 			/* want to reconstruct this device */
3077 			rb2 = r10_bio;
3078 			sect = raid10_find_virt(conf, sector_nr, i);
3079 			if (sect >= mddev->resync_max_sectors) {
3080 				/* last stripe is not complete - don't
3081 				 * try to recover this sector.
3082 				 */
3083 				rcu_read_unlock();
3084 				continue;
3085 			}
3086 			/* Unless we are doing a full sync, or a replacement
3087 			 * we only need to recover the block if it is set in
3088 			 * the bitmap
3089 			 */
3090 			must_sync = md_bitmap_start_sync(mddev->bitmap, sect,
3091 							 &sync_blocks, 1);
3092 			if (sync_blocks < max_sync)
3093 				max_sync = sync_blocks;
3094 			if (!must_sync &&
3095 			    mreplace == NULL &&
3096 			    !conf->fullsync) {
3097 				/* yep, skip the sync_blocks here, but don't assume
3098 				 * that there will never be anything to do here
3099 				 */
3100 				chunks_skipped = -1;
3101 				rcu_read_unlock();
3102 				continue;
3103 			}
3104 			atomic_inc(&mrdev->nr_pending);
3105 			if (mreplace)
3106 				atomic_inc(&mreplace->nr_pending);
3107 			rcu_read_unlock();
3108 
3109 			r10_bio = raid10_alloc_init_r10buf(conf);
3110 			r10_bio->state = 0;
3111 			raise_barrier(conf, rb2 != NULL);
3112 			atomic_set(&r10_bio->remaining, 0);
3113 
3114 			r10_bio->master_bio = (struct bio*)rb2;
3115 			if (rb2)
3116 				atomic_inc(&rb2->remaining);
3117 			r10_bio->mddev = mddev;
3118 			set_bit(R10BIO_IsRecover, &r10_bio->state);
3119 			r10_bio->sector = sect;
3120 
3121 			raid10_find_phys(conf, r10_bio);
3122 
3123 			/* Need to check if the array will still be
3124 			 * degraded
3125 			 */
3126 			rcu_read_lock();
3127 			for (j = 0; j < conf->geo.raid_disks; j++) {
3128 				struct md_rdev *rdev = rcu_dereference(
3129 					conf->mirrors[j].rdev);
3130 				if (rdev == NULL || test_bit(Faulty, &rdev->flags)) {
3131 					still_degraded = 1;
3132 					break;
3133 				}
3134 			}
3135 
3136 			must_sync = md_bitmap_start_sync(mddev->bitmap, sect,
3137 							 &sync_blocks, still_degraded);
3138 
3139 			any_working = 0;
3140 			for (j=0; j<conf->copies;j++) {
3141 				int k;
3142 				int d = r10_bio->devs[j].devnum;
3143 				sector_t from_addr, to_addr;
3144 				struct md_rdev *rdev =
3145 					rcu_dereference(conf->mirrors[d].rdev);
3146 				sector_t sector, first_bad;
3147 				int bad_sectors;
3148 				if (!rdev ||
3149 				    !test_bit(In_sync, &rdev->flags))
3150 					continue;
3151 				/* This is where we read from */
3152 				any_working = 1;
3153 				sector = r10_bio->devs[j].addr;
3154 
3155 				if (is_badblock(rdev, sector, max_sync,
3156 						&first_bad, &bad_sectors)) {
3157 					if (first_bad > sector)
3158 						max_sync = first_bad - sector;
3159 					else {
3160 						bad_sectors -= (sector
3161 								- first_bad);
3162 						if (max_sync > bad_sectors)
3163 							max_sync = bad_sectors;
3164 						continue;
3165 					}
3166 				}
3167 				bio = r10_bio->devs[0].bio;
3168 				bio->bi_next = biolist;
3169 				biolist = bio;
3170 				bio->bi_end_io = end_sync_read;
3171 				bio_set_op_attrs(bio, REQ_OP_READ, 0);
3172 				if (test_bit(FailFast, &rdev->flags))
3173 					bio->bi_opf |= MD_FAILFAST;
3174 				from_addr = r10_bio->devs[j].addr;
3175 				bio->bi_iter.bi_sector = from_addr +
3176 					rdev->data_offset;
3177 				bio_set_dev(bio, rdev->bdev);
3178 				atomic_inc(&rdev->nr_pending);
3179 				/* and we write to 'i' (if not in_sync) */
3180 
3181 				for (k=0; k<conf->copies; k++)
3182 					if (r10_bio->devs[k].devnum == i)
3183 						break;
3184 				BUG_ON(k == conf->copies);
3185 				to_addr = r10_bio->devs[k].addr;
3186 				r10_bio->devs[0].devnum = d;
3187 				r10_bio->devs[0].addr = from_addr;
3188 				r10_bio->devs[1].devnum = i;
3189 				r10_bio->devs[1].addr = to_addr;
3190 
3191 				if (need_recover) {
3192 					bio = r10_bio->devs[1].bio;
3193 					bio->bi_next = biolist;
3194 					biolist = bio;
3195 					bio->bi_end_io = end_sync_write;
3196 					bio_set_op_attrs(bio, REQ_OP_WRITE, 0);
3197 					bio->bi_iter.bi_sector = to_addr
3198 						+ mrdev->data_offset;
3199 					bio_set_dev(bio, mrdev->bdev);
3200 					atomic_inc(&r10_bio->remaining);
3201 				} else
3202 					r10_bio->devs[1].bio->bi_end_io = NULL;
3203 
3204 				/* and maybe write to replacement */
3205 				bio = r10_bio->devs[1].repl_bio;
3206 				if (bio)
3207 					bio->bi_end_io = NULL;
3208 				/* Note: if replace is not NULL, then bio
3209 				 * cannot be NULL as r10buf_pool_alloc will
3210 				 * have allocated it.
3211 				 */
3212 				if (!mreplace)
3213 					break;
3214 				bio->bi_next = biolist;
3215 				biolist = bio;
3216 				bio->bi_end_io = end_sync_write;
3217 				bio_set_op_attrs(bio, REQ_OP_WRITE, 0);
3218 				bio->bi_iter.bi_sector = to_addr +
3219 					mreplace->data_offset;
3220 				bio_set_dev(bio, mreplace->bdev);
3221 				atomic_inc(&r10_bio->remaining);
3222 				break;
3223 			}
3224 			rcu_read_unlock();
3225 			if (j == conf->copies) {
3226 				/* Cannot recover, so abort the recovery or
3227 				 * record a bad block */
3228 				if (any_working) {
3229 					/* problem is that there are bad blocks
3230 					 * on other device(s)
3231 					 */
3232 					int k;
3233 					for (k = 0; k < conf->copies; k++)
3234 						if (r10_bio->devs[k].devnum == i)
3235 							break;
3236 					if (!test_bit(In_sync,
3237 						      &mrdev->flags)
3238 					    && !rdev_set_badblocks(
3239 						    mrdev,
3240 						    r10_bio->devs[k].addr,
3241 						    max_sync, 0))
3242 						any_working = 0;
3243 					if (mreplace &&
3244 					    !rdev_set_badblocks(
3245 						    mreplace,
3246 						    r10_bio->devs[k].addr,
3247 						    max_sync, 0))
3248 						any_working = 0;
3249 				}
3250 				if (!any_working)  {
3251 					if (!test_and_set_bit(MD_RECOVERY_INTR,
3252 							      &mddev->recovery))
3253 						pr_warn("md/raid10:%s: insufficient working devices for recovery.\n",
3254 						       mdname(mddev));
3255 					mirror->recovery_disabled
3256 						= mddev->recovery_disabled;
3257 				}
3258 				put_buf(r10_bio);
3259 				if (rb2)
3260 					atomic_dec(&rb2->remaining);
3261 				r10_bio = rb2;
3262 				rdev_dec_pending(mrdev, mddev);
3263 				if (mreplace)
3264 					rdev_dec_pending(mreplace, mddev);
3265 				break;
3266 			}
3267 			rdev_dec_pending(mrdev, mddev);
3268 			if (mreplace)
3269 				rdev_dec_pending(mreplace, mddev);
3270 			if (r10_bio->devs[0].bio->bi_opf & MD_FAILFAST) {
3271 				/* Only want this if there is elsewhere to
3272 				 * read from. 'j' is currently the first
3273 				 * readable copy.
3274 				 */
3275 				int targets = 1;
3276 				for (; j < conf->copies; j++) {
3277 					int d = r10_bio->devs[j].devnum;
3278 					if (conf->mirrors[d].rdev &&
3279 					    test_bit(In_sync,
3280 						      &conf->mirrors[d].rdev->flags))
3281 						targets++;
3282 				}
3283 				if (targets == 1)
3284 					r10_bio->devs[0].bio->bi_opf
3285 						&= ~MD_FAILFAST;
3286 			}
3287 		}
3288 		if (biolist == NULL) {
3289 			while (r10_bio) {
3290 				struct r10bio *rb2 = r10_bio;
3291 				r10_bio = (struct r10bio*) rb2->master_bio;
3292 				rb2->master_bio = NULL;
3293 				put_buf(rb2);
3294 			}
3295 			goto giveup;
3296 		}
3297 	} else {
3298 		/* resync. Schedule a read for every block at this virt offset */
3299 		int count = 0;
3300 
3301 		/*
3302 		 * Since curr_resync_completed could probably not update in
3303 		 * time, and we will set cluster_sync_low based on it.
3304 		 * Let's check against "sector_nr + 2 * RESYNC_SECTORS" for
3305 		 * safety reason, which ensures curr_resync_completed is
3306 		 * updated in bitmap_cond_end_sync.
3307 		 */
3308 		md_bitmap_cond_end_sync(mddev->bitmap, sector_nr,
3309 					mddev_is_clustered(mddev) &&
3310 					(sector_nr + 2 * RESYNC_SECTORS > conf->cluster_sync_high));
3311 
3312 		if (!md_bitmap_start_sync(mddev->bitmap, sector_nr,
3313 					  &sync_blocks, mddev->degraded) &&
3314 		    !conf->fullsync && !test_bit(MD_RECOVERY_REQUESTED,
3315 						 &mddev->recovery)) {
3316 			/* We can skip this block */
3317 			*skipped = 1;
3318 			return sync_blocks + sectors_skipped;
3319 		}
3320 		if (sync_blocks < max_sync)
3321 			max_sync = sync_blocks;
3322 		r10_bio = raid10_alloc_init_r10buf(conf);
3323 		r10_bio->state = 0;
3324 
3325 		r10_bio->mddev = mddev;
3326 		atomic_set(&r10_bio->remaining, 0);
3327 		raise_barrier(conf, 0);
3328 		conf->next_resync = sector_nr;
3329 
3330 		r10_bio->master_bio = NULL;
3331 		r10_bio->sector = sector_nr;
3332 		set_bit(R10BIO_IsSync, &r10_bio->state);
3333 		raid10_find_phys(conf, r10_bio);
3334 		r10_bio->sectors = (sector_nr | chunk_mask) - sector_nr + 1;
3335 
3336 		for (i = 0; i < conf->copies; i++) {
3337 			int d = r10_bio->devs[i].devnum;
3338 			sector_t first_bad, sector;
3339 			int bad_sectors;
3340 			struct md_rdev *rdev;
3341 
3342 			if (r10_bio->devs[i].repl_bio)
3343 				r10_bio->devs[i].repl_bio->bi_end_io = NULL;
3344 
3345 			bio = r10_bio->devs[i].bio;
3346 			bio->bi_status = BLK_STS_IOERR;
3347 			rcu_read_lock();
3348 			rdev = rcu_dereference(conf->mirrors[d].rdev);
3349 			if (rdev == NULL || test_bit(Faulty, &rdev->flags)) {
3350 				rcu_read_unlock();
3351 				continue;
3352 			}
3353 			sector = r10_bio->devs[i].addr;
3354 			if (is_badblock(rdev, sector, max_sync,
3355 					&first_bad, &bad_sectors)) {
3356 				if (first_bad > sector)
3357 					max_sync = first_bad - sector;
3358 				else {
3359 					bad_sectors -= (sector - first_bad);
3360 					if (max_sync > bad_sectors)
3361 						max_sync = bad_sectors;
3362 					rcu_read_unlock();
3363 					continue;
3364 				}
3365 			}
3366 			atomic_inc(&rdev->nr_pending);
3367 			atomic_inc(&r10_bio->remaining);
3368 			bio->bi_next = biolist;
3369 			biolist = bio;
3370 			bio->bi_end_io = end_sync_read;
3371 			bio_set_op_attrs(bio, REQ_OP_READ, 0);
3372 			if (test_bit(FailFast, &rdev->flags))
3373 				bio->bi_opf |= MD_FAILFAST;
3374 			bio->bi_iter.bi_sector = sector + rdev->data_offset;
3375 			bio_set_dev(bio, rdev->bdev);
3376 			count++;
3377 
3378 			rdev = rcu_dereference(conf->mirrors[d].replacement);
3379 			if (rdev == NULL || test_bit(Faulty, &rdev->flags)) {
3380 				rcu_read_unlock();
3381 				continue;
3382 			}
3383 			atomic_inc(&rdev->nr_pending);
3384 
3385 			/* Need to set up for writing to the replacement */
3386 			bio = r10_bio->devs[i].repl_bio;
3387 			bio->bi_status = BLK_STS_IOERR;
3388 
3389 			sector = r10_bio->devs[i].addr;
3390 			bio->bi_next = biolist;
3391 			biolist = bio;
3392 			bio->bi_end_io = end_sync_write;
3393 			bio_set_op_attrs(bio, REQ_OP_WRITE, 0);
3394 			if (test_bit(FailFast, &rdev->flags))
3395 				bio->bi_opf |= MD_FAILFAST;
3396 			bio->bi_iter.bi_sector = sector + rdev->data_offset;
3397 			bio_set_dev(bio, rdev->bdev);
3398 			count++;
3399 			rcu_read_unlock();
3400 		}
3401 
3402 		if (count < 2) {
3403 			for (i=0; i<conf->copies; i++) {
3404 				int d = r10_bio->devs[i].devnum;
3405 				if (r10_bio->devs[i].bio->bi_end_io)
3406 					rdev_dec_pending(conf->mirrors[d].rdev,
3407 							 mddev);
3408 				if (r10_bio->devs[i].repl_bio &&
3409 				    r10_bio->devs[i].repl_bio->bi_end_io)
3410 					rdev_dec_pending(
3411 						conf->mirrors[d].replacement,
3412 						mddev);
3413 			}
3414 			put_buf(r10_bio);
3415 			biolist = NULL;
3416 			goto giveup;
3417 		}
3418 	}
3419 
3420 	nr_sectors = 0;
3421 	if (sector_nr + max_sync < max_sector)
3422 		max_sector = sector_nr + max_sync;
3423 	do {
3424 		struct page *page;
3425 		int len = PAGE_SIZE;
3426 		if (sector_nr + (len>>9) > max_sector)
3427 			len = (max_sector - sector_nr) << 9;
3428 		if (len == 0)
3429 			break;
3430 		for (bio= biolist ; bio ; bio=bio->bi_next) {
3431 			struct resync_pages *rp = get_resync_pages(bio);
3432 			page = resync_fetch_page(rp, page_idx);
3433 			/*
3434 			 * won't fail because the vec table is big enough
3435 			 * to hold all these pages
3436 			 */
3437 			bio_add_page(bio, page, len, 0);
3438 		}
3439 		nr_sectors += len>>9;
3440 		sector_nr += len>>9;
3441 	} while (++page_idx < RESYNC_PAGES);
3442 	r10_bio->sectors = nr_sectors;
3443 
3444 	if (mddev_is_clustered(mddev) &&
3445 	    test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) {
3446 		/* It is resync not recovery */
3447 		if (conf->cluster_sync_high < sector_nr + nr_sectors) {
3448 			conf->cluster_sync_low = mddev->curr_resync_completed;
3449 			raid10_set_cluster_sync_high(conf);
3450 			/* Send resync message */
3451 			md_cluster_ops->resync_info_update(mddev,
3452 						conf->cluster_sync_low,
3453 						conf->cluster_sync_high);
3454 		}
3455 	} else if (mddev_is_clustered(mddev)) {
3456 		/* This is recovery not resync */
3457 		sector_t sect_va1, sect_va2;
3458 		bool broadcast_msg = false;
3459 
3460 		for (i = 0; i < conf->geo.raid_disks; i++) {
3461 			/*
3462 			 * sector_nr is a device address for recovery, so we
3463 			 * need translate it to array address before compare
3464 			 * with cluster_sync_high.
3465 			 */
3466 			sect_va1 = raid10_find_virt(conf, sector_nr, i);
3467 
3468 			if (conf->cluster_sync_high < sect_va1 + nr_sectors) {
3469 				broadcast_msg = true;
3470 				/*
3471 				 * curr_resync_completed is similar as
3472 				 * sector_nr, so make the translation too.
3473 				 */
3474 				sect_va2 = raid10_find_virt(conf,
3475 					mddev->curr_resync_completed, i);
3476 
3477 				if (conf->cluster_sync_low == 0 ||
3478 				    conf->cluster_sync_low > sect_va2)
3479 					conf->cluster_sync_low = sect_va2;
3480 			}
3481 		}
3482 		if (broadcast_msg) {
3483 			raid10_set_cluster_sync_high(conf);
3484 			md_cluster_ops->resync_info_update(mddev,
3485 						conf->cluster_sync_low,
3486 						conf->cluster_sync_high);
3487 		}
3488 	}
3489 
3490 	while (biolist) {
3491 		bio = biolist;
3492 		biolist = biolist->bi_next;
3493 
3494 		bio->bi_next = NULL;
3495 		r10_bio = get_resync_r10bio(bio);
3496 		r10_bio->sectors = nr_sectors;
3497 
3498 		if (bio->bi_end_io == end_sync_read) {
3499 			md_sync_acct_bio(bio, nr_sectors);
3500 			bio->bi_status = 0;
3501 			submit_bio_noacct(bio);
3502 		}
3503 	}
3504 
3505 	if (sectors_skipped)
3506 		/* pretend they weren't skipped, it makes
3507 		 * no important difference in this case
3508 		 */
3509 		md_done_sync(mddev, sectors_skipped, 1);
3510 
3511 	return sectors_skipped + nr_sectors;
3512  giveup:
3513 	/* There is nowhere to write, so all non-sync
3514 	 * drives must be failed or in resync, all drives
3515 	 * have a bad block, so try the next chunk...
3516 	 */
3517 	if (sector_nr + max_sync < max_sector)
3518 		max_sector = sector_nr + max_sync;
3519 
3520 	sectors_skipped += (max_sector - sector_nr);
3521 	chunks_skipped ++;
3522 	sector_nr = max_sector;
3523 	goto skipped;
3524 }
3525 
3526 static sector_t
raid10_size(struct mddev *mddev, sector_t sectors, int raid_disks)3527 raid10_size(struct mddev *mddev, sector_t sectors, int raid_disks)
3528 {
3529 	sector_t size;
3530 	struct r10conf *conf = mddev->private;
3531 
3532 	if (!raid_disks)
3533 		raid_disks = min(conf->geo.raid_disks,
3534 				 conf->prev.raid_disks);
3535 	if (!sectors)
3536 		sectors = conf->dev_sectors;
3537 
3538 	size = sectors >> conf->geo.chunk_shift;
3539 	sector_div(size, conf->geo.far_copies);
3540 	size = size * raid_disks;
3541 	sector_div(size, conf->geo.near_copies);
3542 
3543 	return size << conf->geo.chunk_shift;
3544 }
3545 
calc_sectors(struct r10conf *conf, sector_t size)3546 static void calc_sectors(struct r10conf *conf, sector_t size)
3547 {
3548 	/* Calculate the number of sectors-per-device that will
3549 	 * actually be used, and set conf->dev_sectors and
3550 	 * conf->stride
3551 	 */
3552 
3553 	size = size >> conf->geo.chunk_shift;
3554 	sector_div(size, conf->geo.far_copies);
3555 	size = size * conf->geo.raid_disks;
3556 	sector_div(size, conf->geo.near_copies);
3557 	/* 'size' is now the number of chunks in the array */
3558 	/* calculate "used chunks per device" */
3559 	size = size * conf->copies;
3560 
3561 	/* We need to round up when dividing by raid_disks to
3562 	 * get the stride size.
3563 	 */
3564 	size = DIV_ROUND_UP_SECTOR_T(size, conf->geo.raid_disks);
3565 
3566 	conf->dev_sectors = size << conf->geo.chunk_shift;
3567 
3568 	if (conf->geo.far_offset)
3569 		conf->geo.stride = 1 << conf->geo.chunk_shift;
3570 	else {
3571 		sector_div(size, conf->geo.far_copies);
3572 		conf->geo.stride = size << conf->geo.chunk_shift;
3573 	}
3574 }
3575 
3576 enum geo_type {geo_new, geo_old, geo_start};
setup_geo(struct geom *geo, struct mddev *mddev, enum geo_type new)3577 static int setup_geo(struct geom *geo, struct mddev *mddev, enum geo_type new)
3578 {
3579 	int nc, fc, fo;
3580 	int layout, chunk, disks;
3581 	switch (new) {
3582 	case geo_old:
3583 		layout = mddev->layout;
3584 		chunk = mddev->chunk_sectors;
3585 		disks = mddev->raid_disks - mddev->delta_disks;
3586 		break;
3587 	case geo_new:
3588 		layout = mddev->new_layout;
3589 		chunk = mddev->new_chunk_sectors;
3590 		disks = mddev->raid_disks;
3591 		break;
3592 	default: /* avoid 'may be unused' warnings */
3593 	case geo_start: /* new when starting reshape - raid_disks not
3594 			 * updated yet. */
3595 		layout = mddev->new_layout;
3596 		chunk = mddev->new_chunk_sectors;
3597 		disks = mddev->raid_disks + mddev->delta_disks;
3598 		break;
3599 	}
3600 	if (layout >> 19)
3601 		return -1;
3602 	if (chunk < (PAGE_SIZE >> 9) ||
3603 	    !is_power_of_2(chunk))
3604 		return -2;
3605 	nc = layout & 255;
3606 	fc = (layout >> 8) & 255;
3607 	fo = layout & (1<<16);
3608 	geo->raid_disks = disks;
3609 	geo->near_copies = nc;
3610 	geo->far_copies = fc;
3611 	geo->far_offset = fo;
3612 	switch (layout >> 17) {
3613 	case 0:	/* original layout.  simple but not always optimal */
3614 		geo->far_set_size = disks;
3615 		break;
3616 	case 1: /* "improved" layout which was buggy.  Hopefully no-one is
3617 		 * actually using this, but leave code here just in case.*/
3618 		geo->far_set_size = disks/fc;
3619 		WARN(geo->far_set_size < fc,
3620 		     "This RAID10 layout does not provide data safety - please backup and create new array\n");
3621 		break;
3622 	case 2: /* "improved" layout fixed to match documentation */
3623 		geo->far_set_size = fc * nc;
3624 		break;
3625 	default: /* Not a valid layout */
3626 		return -1;
3627 	}
3628 	geo->chunk_mask = chunk - 1;
3629 	geo->chunk_shift = ffz(~chunk);
3630 	return nc*fc;
3631 }
3632 
raid10_free_conf(struct r10conf *conf)3633 static void raid10_free_conf(struct r10conf *conf)
3634 {
3635 	if (!conf)
3636 		return;
3637 
3638 	mempool_exit(&conf->r10bio_pool);
3639 	kfree(conf->mirrors);
3640 	kfree(conf->mirrors_old);
3641 	kfree(conf->mirrors_new);
3642 	safe_put_page(conf->tmppage);
3643 	bioset_exit(&conf->bio_split);
3644 	kfree(conf);
3645 }
3646 
setup_conf(struct mddev *mddev)3647 static struct r10conf *setup_conf(struct mddev *mddev)
3648 {
3649 	struct r10conf *conf = NULL;
3650 	int err = -EINVAL;
3651 	struct geom geo;
3652 	int copies;
3653 
3654 	copies = setup_geo(&geo, mddev, geo_new);
3655 
3656 	if (copies == -2) {
3657 		pr_warn("md/raid10:%s: chunk size must be at least PAGE_SIZE(%ld) and be a power of 2.\n",
3658 			mdname(mddev), PAGE_SIZE);
3659 		goto out;
3660 	}
3661 
3662 	if (copies < 2 || copies > mddev->raid_disks) {
3663 		pr_warn("md/raid10:%s: unsupported raid10 layout: 0x%8x\n",
3664 			mdname(mddev), mddev->new_layout);
3665 		goto out;
3666 	}
3667 
3668 	err = -ENOMEM;
3669 	conf = kzalloc(sizeof(struct r10conf), GFP_KERNEL);
3670 	if (!conf)
3671 		goto out;
3672 
3673 	/* FIXME calc properly */
3674 	conf->mirrors = kcalloc(mddev->raid_disks + max(0, -mddev->delta_disks),
3675 				sizeof(struct raid10_info),
3676 				GFP_KERNEL);
3677 	if (!conf->mirrors)
3678 		goto out;
3679 
3680 	conf->tmppage = alloc_page(GFP_KERNEL);
3681 	if (!conf->tmppage)
3682 		goto out;
3683 
3684 	conf->geo = geo;
3685 	conf->copies = copies;
3686 	err = mempool_init(&conf->r10bio_pool, NR_RAID_BIOS, r10bio_pool_alloc,
3687 			   rbio_pool_free, conf);
3688 	if (err)
3689 		goto out;
3690 
3691 	err = bioset_init(&conf->bio_split, BIO_POOL_SIZE, 0, 0);
3692 	if (err)
3693 		goto out;
3694 
3695 	calc_sectors(conf, mddev->dev_sectors);
3696 	if (mddev->reshape_position == MaxSector) {
3697 		conf->prev = conf->geo;
3698 		conf->reshape_progress = MaxSector;
3699 	} else {
3700 		if (setup_geo(&conf->prev, mddev, geo_old) != conf->copies) {
3701 			err = -EINVAL;
3702 			goto out;
3703 		}
3704 		conf->reshape_progress = mddev->reshape_position;
3705 		if (conf->prev.far_offset)
3706 			conf->prev.stride = 1 << conf->prev.chunk_shift;
3707 		else
3708 			/* far_copies must be 1 */
3709 			conf->prev.stride = conf->dev_sectors;
3710 	}
3711 	conf->reshape_safe = conf->reshape_progress;
3712 	spin_lock_init(&conf->device_lock);
3713 	INIT_LIST_HEAD(&conf->retry_list);
3714 	INIT_LIST_HEAD(&conf->bio_end_io_list);
3715 
3716 	spin_lock_init(&conf->resync_lock);
3717 	init_waitqueue_head(&conf->wait_barrier);
3718 	atomic_set(&conf->nr_pending, 0);
3719 
3720 	err = -ENOMEM;
3721 	conf->thread = md_register_thread(raid10d, mddev, "raid10");
3722 	if (!conf->thread)
3723 		goto out;
3724 
3725 	conf->mddev = mddev;
3726 	return conf;
3727 
3728  out:
3729 	raid10_free_conf(conf);
3730 	return ERR_PTR(err);
3731 }
3732 
raid10_set_io_opt(struct r10conf *conf)3733 static void raid10_set_io_opt(struct r10conf *conf)
3734 {
3735 	int raid_disks = conf->geo.raid_disks;
3736 
3737 	if (!(conf->geo.raid_disks % conf->geo.near_copies))
3738 		raid_disks /= conf->geo.near_copies;
3739 	blk_queue_io_opt(conf->mddev->queue, (conf->mddev->chunk_sectors << 9) *
3740 			 raid_disks);
3741 }
3742 
raid10_run(struct mddev *mddev)3743 static int raid10_run(struct mddev *mddev)
3744 {
3745 	struct r10conf *conf;
3746 	int i, disk_idx;
3747 	struct raid10_info *disk;
3748 	struct md_rdev *rdev;
3749 	sector_t size;
3750 	sector_t min_offset_diff = 0;
3751 	int first = 1;
3752 	bool discard_supported = false;
3753 
3754 	if (mddev_init_writes_pending(mddev) < 0)
3755 		return -ENOMEM;
3756 
3757 	if (mddev->private == NULL) {
3758 		conf = setup_conf(mddev);
3759 		if (IS_ERR(conf))
3760 			return PTR_ERR(conf);
3761 		mddev->private = conf;
3762 	}
3763 	conf = mddev->private;
3764 	if (!conf)
3765 		goto out;
3766 
3767 	mddev->thread = conf->thread;
3768 	conf->thread = NULL;
3769 
3770 	if (mddev_is_clustered(conf->mddev)) {
3771 		int fc, fo;
3772 
3773 		fc = (mddev->layout >> 8) & 255;
3774 		fo = mddev->layout & (1<<16);
3775 		if (fc > 1 || fo > 0) {
3776 			pr_err("only near layout is supported by clustered"
3777 				" raid10\n");
3778 			goto out_free_conf;
3779 		}
3780 	}
3781 
3782 	if (mddev->queue) {
3783 		blk_queue_max_discard_sectors(mddev->queue,
3784 					      mddev->chunk_sectors);
3785 		blk_queue_max_write_same_sectors(mddev->queue, 0);
3786 		blk_queue_max_write_zeroes_sectors(mddev->queue, 0);
3787 		blk_queue_io_min(mddev->queue, mddev->chunk_sectors << 9);
3788 		raid10_set_io_opt(conf);
3789 	}
3790 
3791 	rdev_for_each(rdev, mddev) {
3792 		long long diff;
3793 
3794 		disk_idx = rdev->raid_disk;
3795 		if (disk_idx < 0)
3796 			continue;
3797 		if (disk_idx >= conf->geo.raid_disks &&
3798 		    disk_idx >= conf->prev.raid_disks)
3799 			continue;
3800 		disk = conf->mirrors + disk_idx;
3801 
3802 		if (test_bit(Replacement, &rdev->flags)) {
3803 			if (disk->replacement)
3804 				goto out_free_conf;
3805 			disk->replacement = rdev;
3806 		} else {
3807 			if (disk->rdev)
3808 				goto out_free_conf;
3809 			disk->rdev = rdev;
3810 		}
3811 		diff = (rdev->new_data_offset - rdev->data_offset);
3812 		if (!mddev->reshape_backwards)
3813 			diff = -diff;
3814 		if (diff < 0)
3815 			diff = 0;
3816 		if (first || diff < min_offset_diff)
3817 			min_offset_diff = diff;
3818 
3819 		if (mddev->gendisk)
3820 			disk_stack_limits(mddev->gendisk, rdev->bdev,
3821 					  rdev->data_offset << 9);
3822 
3823 		disk->head_position = 0;
3824 
3825 		if (blk_queue_discard(bdev_get_queue(rdev->bdev)))
3826 			discard_supported = true;
3827 		first = 0;
3828 	}
3829 
3830 	if (mddev->queue) {
3831 		if (discard_supported)
3832 			blk_queue_flag_set(QUEUE_FLAG_DISCARD,
3833 						mddev->queue);
3834 		else
3835 			blk_queue_flag_clear(QUEUE_FLAG_DISCARD,
3836 						  mddev->queue);
3837 	}
3838 	/* need to check that every block has at least one working mirror */
3839 	if (!enough(conf, -1)) {
3840 		pr_err("md/raid10:%s: not enough operational mirrors.\n",
3841 		       mdname(mddev));
3842 		goto out_free_conf;
3843 	}
3844 
3845 	if (conf->reshape_progress != MaxSector) {
3846 		/* must ensure that shape change is supported */
3847 		if (conf->geo.far_copies != 1 &&
3848 		    conf->geo.far_offset == 0)
3849 			goto out_free_conf;
3850 		if (conf->prev.far_copies != 1 &&
3851 		    conf->prev.far_offset == 0)
3852 			goto out_free_conf;
3853 	}
3854 
3855 	mddev->degraded = 0;
3856 	for (i = 0;
3857 	     i < conf->geo.raid_disks
3858 		     || i < conf->prev.raid_disks;
3859 	     i++) {
3860 
3861 		disk = conf->mirrors + i;
3862 
3863 		if (!disk->rdev && disk->replacement) {
3864 			/* The replacement is all we have - use it */
3865 			disk->rdev = disk->replacement;
3866 			disk->replacement = NULL;
3867 			clear_bit(Replacement, &disk->rdev->flags);
3868 		}
3869 
3870 		if (!disk->rdev ||
3871 		    !test_bit(In_sync, &disk->rdev->flags)) {
3872 			disk->head_position = 0;
3873 			mddev->degraded++;
3874 			if (disk->rdev &&
3875 			    disk->rdev->saved_raid_disk < 0)
3876 				conf->fullsync = 1;
3877 		}
3878 
3879 		if (disk->replacement &&
3880 		    !test_bit(In_sync, &disk->replacement->flags) &&
3881 		    disk->replacement->saved_raid_disk < 0) {
3882 			conf->fullsync = 1;
3883 		}
3884 
3885 		disk->recovery_disabled = mddev->recovery_disabled - 1;
3886 	}
3887 
3888 	if (mddev->recovery_cp != MaxSector)
3889 		pr_notice("md/raid10:%s: not clean -- starting background reconstruction\n",
3890 			  mdname(mddev));
3891 	pr_info("md/raid10:%s: active with %d out of %d devices\n",
3892 		mdname(mddev), conf->geo.raid_disks - mddev->degraded,
3893 		conf->geo.raid_disks);
3894 	/*
3895 	 * Ok, everything is just fine now
3896 	 */
3897 	mddev->dev_sectors = conf->dev_sectors;
3898 	size = raid10_size(mddev, 0, 0);
3899 	md_set_array_sectors(mddev, size);
3900 	mddev->resync_max_sectors = size;
3901 	set_bit(MD_FAILFAST_SUPPORTED, &mddev->flags);
3902 
3903 	if (md_integrity_register(mddev))
3904 		goto out_free_conf;
3905 
3906 	if (conf->reshape_progress != MaxSector) {
3907 		unsigned long before_length, after_length;
3908 
3909 		before_length = ((1 << conf->prev.chunk_shift) *
3910 				 conf->prev.far_copies);
3911 		after_length = ((1 << conf->geo.chunk_shift) *
3912 				conf->geo.far_copies);
3913 
3914 		if (max(before_length, after_length) > min_offset_diff) {
3915 			/* This cannot work */
3916 			pr_warn("md/raid10: offset difference not enough to continue reshape\n");
3917 			goto out_free_conf;
3918 		}
3919 		conf->offset_diff = min_offset_diff;
3920 
3921 		clear_bit(MD_RECOVERY_SYNC, &mddev->recovery);
3922 		clear_bit(MD_RECOVERY_CHECK, &mddev->recovery);
3923 		set_bit(MD_RECOVERY_RESHAPE, &mddev->recovery);
3924 		set_bit(MD_RECOVERY_RUNNING, &mddev->recovery);
3925 		mddev->sync_thread = md_register_thread(md_do_sync, mddev,
3926 							"reshape");
3927 		if (!mddev->sync_thread)
3928 			goto out_free_conf;
3929 	}
3930 
3931 	return 0;
3932 
3933 out_free_conf:
3934 	md_unregister_thread(&mddev->thread);
3935 	raid10_free_conf(conf);
3936 	mddev->private = NULL;
3937 out:
3938 	return -EIO;
3939 }
3940 
raid10_free(struct mddev *mddev, void *priv)3941 static void raid10_free(struct mddev *mddev, void *priv)
3942 {
3943 	raid10_free_conf(priv);
3944 }
3945 
raid10_quiesce(struct mddev *mddev, int quiesce)3946 static void raid10_quiesce(struct mddev *mddev, int quiesce)
3947 {
3948 	struct r10conf *conf = mddev->private;
3949 
3950 	if (quiesce)
3951 		raise_barrier(conf, 0);
3952 	else
3953 		lower_barrier(conf);
3954 }
3955 
raid10_resize(struct mddev *mddev, sector_t sectors)3956 static int raid10_resize(struct mddev *mddev, sector_t sectors)
3957 {
3958 	/* Resize of 'far' arrays is not supported.
3959 	 * For 'near' and 'offset' arrays we can set the
3960 	 * number of sectors used to be an appropriate multiple
3961 	 * of the chunk size.
3962 	 * For 'offset', this is far_copies*chunksize.
3963 	 * For 'near' the multiplier is the LCM of
3964 	 * near_copies and raid_disks.
3965 	 * So if far_copies > 1 && !far_offset, fail.
3966 	 * Else find LCM(raid_disks, near_copy)*far_copies and
3967 	 * multiply by chunk_size.  Then round to this number.
3968 	 * This is mostly done by raid10_size()
3969 	 */
3970 	struct r10conf *conf = mddev->private;
3971 	sector_t oldsize, size;
3972 
3973 	if (mddev->reshape_position != MaxSector)
3974 		return -EBUSY;
3975 
3976 	if (conf->geo.far_copies > 1 && !conf->geo.far_offset)
3977 		return -EINVAL;
3978 
3979 	oldsize = raid10_size(mddev, 0, 0);
3980 	size = raid10_size(mddev, sectors, 0);
3981 	if (mddev->external_size &&
3982 	    mddev->array_sectors > size)
3983 		return -EINVAL;
3984 	if (mddev->bitmap) {
3985 		int ret = md_bitmap_resize(mddev->bitmap, size, 0, 0);
3986 		if (ret)
3987 			return ret;
3988 	}
3989 	md_set_array_sectors(mddev, size);
3990 	if (sectors > mddev->dev_sectors &&
3991 	    mddev->recovery_cp > oldsize) {
3992 		mddev->recovery_cp = oldsize;
3993 		set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
3994 	}
3995 	calc_sectors(conf, sectors);
3996 	mddev->dev_sectors = conf->dev_sectors;
3997 	mddev->resync_max_sectors = size;
3998 	return 0;
3999 }
4000 
raid10_takeover_raid0(struct mddev *mddev, sector_t size, int devs)4001 static void *raid10_takeover_raid0(struct mddev *mddev, sector_t size, int devs)
4002 {
4003 	struct md_rdev *rdev;
4004 	struct r10conf *conf;
4005 
4006 	if (mddev->degraded > 0) {
4007 		pr_warn("md/raid10:%s: Error: degraded raid0!\n",
4008 			mdname(mddev));
4009 		return ERR_PTR(-EINVAL);
4010 	}
4011 	sector_div(size, devs);
4012 
4013 	/* Set new parameters */
4014 	mddev->new_level = 10;
4015 	/* new layout: far_copies = 1, near_copies = 2 */
4016 	mddev->new_layout = (1<<8) + 2;
4017 	mddev->new_chunk_sectors = mddev->chunk_sectors;
4018 	mddev->delta_disks = mddev->raid_disks;
4019 	mddev->raid_disks *= 2;
4020 	/* make sure it will be not marked as dirty */
4021 	mddev->recovery_cp = MaxSector;
4022 	mddev->dev_sectors = size;
4023 
4024 	conf = setup_conf(mddev);
4025 	if (!IS_ERR(conf)) {
4026 		rdev_for_each(rdev, mddev)
4027 			if (rdev->raid_disk >= 0) {
4028 				rdev->new_raid_disk = rdev->raid_disk * 2;
4029 				rdev->sectors = size;
4030 			}
4031 		conf->barrier = 1;
4032 	}
4033 
4034 	return conf;
4035 }
4036 
raid10_takeover(struct mddev *mddev)4037 static void *raid10_takeover(struct mddev *mddev)
4038 {
4039 	struct r0conf *raid0_conf;
4040 
4041 	/* raid10 can take over:
4042 	 *  raid0 - providing it has only two drives
4043 	 */
4044 	if (mddev->level == 0) {
4045 		/* for raid0 takeover only one zone is supported */
4046 		raid0_conf = mddev->private;
4047 		if (raid0_conf->nr_strip_zones > 1) {
4048 			pr_warn("md/raid10:%s: cannot takeover raid 0 with more than one zone.\n",
4049 				mdname(mddev));
4050 			return ERR_PTR(-EINVAL);
4051 		}
4052 		return raid10_takeover_raid0(mddev,
4053 			raid0_conf->strip_zone->zone_end,
4054 			raid0_conf->strip_zone->nb_dev);
4055 	}
4056 	return ERR_PTR(-EINVAL);
4057 }
4058 
raid10_check_reshape(struct mddev *mddev)4059 static int raid10_check_reshape(struct mddev *mddev)
4060 {
4061 	/* Called when there is a request to change
4062 	 * - layout (to ->new_layout)
4063 	 * - chunk size (to ->new_chunk_sectors)
4064 	 * - raid_disks (by delta_disks)
4065 	 * or when trying to restart a reshape that was ongoing.
4066 	 *
4067 	 * We need to validate the request and possibly allocate
4068 	 * space if that might be an issue later.
4069 	 *
4070 	 * Currently we reject any reshape of a 'far' mode array,
4071 	 * allow chunk size to change if new is generally acceptable,
4072 	 * allow raid_disks to increase, and allow
4073 	 * a switch between 'near' mode and 'offset' mode.
4074 	 */
4075 	struct r10conf *conf = mddev->private;
4076 	struct geom geo;
4077 
4078 	if (conf->geo.far_copies != 1 && !conf->geo.far_offset)
4079 		return -EINVAL;
4080 
4081 	if (setup_geo(&geo, mddev, geo_start) != conf->copies)
4082 		/* mustn't change number of copies */
4083 		return -EINVAL;
4084 	if (geo.far_copies > 1 && !geo.far_offset)
4085 		/* Cannot switch to 'far' mode */
4086 		return -EINVAL;
4087 
4088 	if (mddev->array_sectors & geo.chunk_mask)
4089 			/* not factor of array size */
4090 			return -EINVAL;
4091 
4092 	if (!enough(conf, -1))
4093 		return -EINVAL;
4094 
4095 	kfree(conf->mirrors_new);
4096 	conf->mirrors_new = NULL;
4097 	if (mddev->delta_disks > 0) {
4098 		/* allocate new 'mirrors' list */
4099 		conf->mirrors_new =
4100 			kcalloc(mddev->raid_disks + mddev->delta_disks,
4101 				sizeof(struct raid10_info),
4102 				GFP_KERNEL);
4103 		if (!conf->mirrors_new)
4104 			return -ENOMEM;
4105 	}
4106 	return 0;
4107 }
4108 
4109 /*
4110  * Need to check if array has failed when deciding whether to:
4111  *  - start an array
4112  *  - remove non-faulty devices
4113  *  - add a spare
4114  *  - allow a reshape
4115  * This determination is simple when no reshape is happening.
4116  * However if there is a reshape, we need to carefully check
4117  * both the before and after sections.
4118  * This is because some failed devices may only affect one
4119  * of the two sections, and some non-in_sync devices may
4120  * be insync in the section most affected by failed devices.
4121  */
calc_degraded(struct r10conf *conf)4122 static int calc_degraded(struct r10conf *conf)
4123 {
4124 	int degraded, degraded2;
4125 	int i;
4126 
4127 	rcu_read_lock();
4128 	degraded = 0;
4129 	/* 'prev' section first */
4130 	for (i = 0; i < conf->prev.raid_disks; i++) {
4131 		struct md_rdev *rdev = rcu_dereference(conf->mirrors[i].rdev);
4132 		if (!rdev || test_bit(Faulty, &rdev->flags))
4133 			degraded++;
4134 		else if (!test_bit(In_sync, &rdev->flags))
4135 			/* When we can reduce the number of devices in
4136 			 * an array, this might not contribute to
4137 			 * 'degraded'.  It does now.
4138 			 */
4139 			degraded++;
4140 	}
4141 	rcu_read_unlock();
4142 	if (conf->geo.raid_disks == conf->prev.raid_disks)
4143 		return degraded;
4144 	rcu_read_lock();
4145 	degraded2 = 0;
4146 	for (i = 0; i < conf->geo.raid_disks; i++) {
4147 		struct md_rdev *rdev = rcu_dereference(conf->mirrors[i].rdev);
4148 		if (!rdev || test_bit(Faulty, &rdev->flags))
4149 			degraded2++;
4150 		else if (!test_bit(In_sync, &rdev->flags)) {
4151 			/* If reshape is increasing the number of devices,
4152 			 * this section has already been recovered, so
4153 			 * it doesn't contribute to degraded.
4154 			 * else it does.
4155 			 */
4156 			if (conf->geo.raid_disks <= conf->prev.raid_disks)
4157 				degraded2++;
4158 		}
4159 	}
4160 	rcu_read_unlock();
4161 	if (degraded2 > degraded)
4162 		return degraded2;
4163 	return degraded;
4164 }
4165 
raid10_start_reshape(struct mddev *mddev)4166 static int raid10_start_reshape(struct mddev *mddev)
4167 {
4168 	/* A 'reshape' has been requested. This commits
4169 	 * the various 'new' fields and sets MD_RECOVER_RESHAPE
4170 	 * This also checks if there are enough spares and adds them
4171 	 * to the array.
4172 	 * We currently require enough spares to make the final
4173 	 * array non-degraded.  We also require that the difference
4174 	 * between old and new data_offset - on each device - is
4175 	 * enough that we never risk over-writing.
4176 	 */
4177 
4178 	unsigned long before_length, after_length;
4179 	sector_t min_offset_diff = 0;
4180 	int first = 1;
4181 	struct geom new;
4182 	struct r10conf *conf = mddev->private;
4183 	struct md_rdev *rdev;
4184 	int spares = 0;
4185 	int ret;
4186 
4187 	if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery))
4188 		return -EBUSY;
4189 
4190 	if (setup_geo(&new, mddev, geo_start) != conf->copies)
4191 		return -EINVAL;
4192 
4193 	before_length = ((1 << conf->prev.chunk_shift) *
4194 			 conf->prev.far_copies);
4195 	after_length = ((1 << conf->geo.chunk_shift) *
4196 			conf->geo.far_copies);
4197 
4198 	rdev_for_each(rdev, mddev) {
4199 		if (!test_bit(In_sync, &rdev->flags)
4200 		    && !test_bit(Faulty, &rdev->flags))
4201 			spares++;
4202 		if (rdev->raid_disk >= 0) {
4203 			long long diff = (rdev->new_data_offset
4204 					  - rdev->data_offset);
4205 			if (!mddev->reshape_backwards)
4206 				diff = -diff;
4207 			if (diff < 0)
4208 				diff = 0;
4209 			if (first || diff < min_offset_diff)
4210 				min_offset_diff = diff;
4211 			first = 0;
4212 		}
4213 	}
4214 
4215 	if (max(before_length, after_length) > min_offset_diff)
4216 		return -EINVAL;
4217 
4218 	if (spares < mddev->delta_disks)
4219 		return -EINVAL;
4220 
4221 	conf->offset_diff = min_offset_diff;
4222 	spin_lock_irq(&conf->device_lock);
4223 	if (conf->mirrors_new) {
4224 		memcpy(conf->mirrors_new, conf->mirrors,
4225 		       sizeof(struct raid10_info)*conf->prev.raid_disks);
4226 		smp_mb();
4227 		kfree(conf->mirrors_old);
4228 		conf->mirrors_old = conf->mirrors;
4229 		conf->mirrors = conf->mirrors_new;
4230 		conf->mirrors_new = NULL;
4231 	}
4232 	setup_geo(&conf->geo, mddev, geo_start);
4233 	smp_mb();
4234 	if (mddev->reshape_backwards) {
4235 		sector_t size = raid10_size(mddev, 0, 0);
4236 		if (size < mddev->array_sectors) {
4237 			spin_unlock_irq(&conf->device_lock);
4238 			pr_warn("md/raid10:%s: array size must be reduce before number of disks\n",
4239 				mdname(mddev));
4240 			return -EINVAL;
4241 		}
4242 		mddev->resync_max_sectors = size;
4243 		conf->reshape_progress = size;
4244 	} else
4245 		conf->reshape_progress = 0;
4246 	conf->reshape_safe = conf->reshape_progress;
4247 	spin_unlock_irq(&conf->device_lock);
4248 
4249 	if (mddev->delta_disks && mddev->bitmap) {
4250 		struct mdp_superblock_1 *sb = NULL;
4251 		sector_t oldsize, newsize;
4252 
4253 		oldsize = raid10_size(mddev, 0, 0);
4254 		newsize = raid10_size(mddev, 0, conf->geo.raid_disks);
4255 
4256 		if (!mddev_is_clustered(mddev)) {
4257 			ret = md_bitmap_resize(mddev->bitmap, newsize, 0, 0);
4258 			if (ret)
4259 				goto abort;
4260 			else
4261 				goto out;
4262 		}
4263 
4264 		rdev_for_each(rdev, mddev) {
4265 			if (rdev->raid_disk > -1 &&
4266 			    !test_bit(Faulty, &rdev->flags))
4267 				sb = page_address(rdev->sb_page);
4268 		}
4269 
4270 		/*
4271 		 * some node is already performing reshape, and no need to
4272 		 * call md_bitmap_resize again since it should be called when
4273 		 * receiving BITMAP_RESIZE msg
4274 		 */
4275 		if ((sb && (le32_to_cpu(sb->feature_map) &
4276 			    MD_FEATURE_RESHAPE_ACTIVE)) || (oldsize == newsize))
4277 			goto out;
4278 
4279 		ret = md_bitmap_resize(mddev->bitmap, newsize, 0, 0);
4280 		if (ret)
4281 			goto abort;
4282 
4283 		ret = md_cluster_ops->resize_bitmaps(mddev, newsize, oldsize);
4284 		if (ret) {
4285 			md_bitmap_resize(mddev->bitmap, oldsize, 0, 0);
4286 			goto abort;
4287 		}
4288 	}
4289 out:
4290 	if (mddev->delta_disks > 0) {
4291 		rdev_for_each(rdev, mddev)
4292 			if (rdev->raid_disk < 0 &&
4293 			    !test_bit(Faulty, &rdev->flags)) {
4294 				if (raid10_add_disk(mddev, rdev) == 0) {
4295 					if (rdev->raid_disk >=
4296 					    conf->prev.raid_disks)
4297 						set_bit(In_sync, &rdev->flags);
4298 					else
4299 						rdev->recovery_offset = 0;
4300 
4301 					/* Failure here is OK */
4302 					sysfs_link_rdev(mddev, rdev);
4303 				}
4304 			} else if (rdev->raid_disk >= conf->prev.raid_disks
4305 				   && !test_bit(Faulty, &rdev->flags)) {
4306 				/* This is a spare that was manually added */
4307 				set_bit(In_sync, &rdev->flags);
4308 			}
4309 	}
4310 	/* When a reshape changes the number of devices,
4311 	 * ->degraded is measured against the larger of the
4312 	 * pre and  post numbers.
4313 	 */
4314 	spin_lock_irq(&conf->device_lock);
4315 	mddev->degraded = calc_degraded(conf);
4316 	spin_unlock_irq(&conf->device_lock);
4317 	mddev->raid_disks = conf->geo.raid_disks;
4318 	mddev->reshape_position = conf->reshape_progress;
4319 	set_bit(MD_SB_CHANGE_DEVS, &mddev->sb_flags);
4320 
4321 	clear_bit(MD_RECOVERY_SYNC, &mddev->recovery);
4322 	clear_bit(MD_RECOVERY_CHECK, &mddev->recovery);
4323 	clear_bit(MD_RECOVERY_DONE, &mddev->recovery);
4324 	set_bit(MD_RECOVERY_RESHAPE, &mddev->recovery);
4325 	set_bit(MD_RECOVERY_RUNNING, &mddev->recovery);
4326 
4327 	mddev->sync_thread = md_register_thread(md_do_sync, mddev,
4328 						"reshape");
4329 	if (!mddev->sync_thread) {
4330 		ret = -EAGAIN;
4331 		goto abort;
4332 	}
4333 	conf->reshape_checkpoint = jiffies;
4334 	md_wakeup_thread(mddev->sync_thread);
4335 	md_new_event(mddev);
4336 	return 0;
4337 
4338 abort:
4339 	mddev->recovery = 0;
4340 	spin_lock_irq(&conf->device_lock);
4341 	conf->geo = conf->prev;
4342 	mddev->raid_disks = conf->geo.raid_disks;
4343 	rdev_for_each(rdev, mddev)
4344 		rdev->new_data_offset = rdev->data_offset;
4345 	smp_wmb();
4346 	conf->reshape_progress = MaxSector;
4347 	conf->reshape_safe = MaxSector;
4348 	mddev->reshape_position = MaxSector;
4349 	spin_unlock_irq(&conf->device_lock);
4350 	return ret;
4351 }
4352 
4353 /* Calculate the last device-address that could contain
4354  * any block from the chunk that includes the array-address 's'
4355  * and report the next address.
4356  * i.e. the address returned will be chunk-aligned and after
4357  * any data that is in the chunk containing 's'.
4358  */
last_dev_address(sector_t s, struct geom *geo)4359 static sector_t last_dev_address(sector_t s, struct geom *geo)
4360 {
4361 	s = (s | geo->chunk_mask) + 1;
4362 	s >>= geo->chunk_shift;
4363 	s *= geo->near_copies;
4364 	s = DIV_ROUND_UP_SECTOR_T(s, geo->raid_disks);
4365 	s *= geo->far_copies;
4366 	s <<= geo->chunk_shift;
4367 	return s;
4368 }
4369 
4370 /* Calculate the first device-address that could contain
4371  * any block from the chunk that includes the array-address 's'.
4372  * This too will be the start of a chunk
4373  */
first_dev_address(sector_t s, struct geom *geo)4374 static sector_t first_dev_address(sector_t s, struct geom *geo)
4375 {
4376 	s >>= geo->chunk_shift;
4377 	s *= geo->near_copies;
4378 	sector_div(s, geo->raid_disks);
4379 	s *= geo->far_copies;
4380 	s <<= geo->chunk_shift;
4381 	return s;
4382 }
4383 
reshape_request(struct mddev *mddev, sector_t sector_nr, int *skipped)4384 static sector_t reshape_request(struct mddev *mddev, sector_t sector_nr,
4385 				int *skipped)
4386 {
4387 	/* We simply copy at most one chunk (smallest of old and new)
4388 	 * at a time, possibly less if that exceeds RESYNC_PAGES,
4389 	 * or we hit a bad block or something.
4390 	 * This might mean we pause for normal IO in the middle of
4391 	 * a chunk, but that is not a problem as mddev->reshape_position
4392 	 * can record any location.
4393 	 *
4394 	 * If we will want to write to a location that isn't
4395 	 * yet recorded as 'safe' (i.e. in metadata on disk) then
4396 	 * we need to flush all reshape requests and update the metadata.
4397 	 *
4398 	 * When reshaping forwards (e.g. to more devices), we interpret
4399 	 * 'safe' as the earliest block which might not have been copied
4400 	 * down yet.  We divide this by previous stripe size and multiply
4401 	 * by previous stripe length to get lowest device offset that we
4402 	 * cannot write to yet.
4403 	 * We interpret 'sector_nr' as an address that we want to write to.
4404 	 * From this we use last_device_address() to find where we might
4405 	 * write to, and first_device_address on the  'safe' position.
4406 	 * If this 'next' write position is after the 'safe' position,
4407 	 * we must update the metadata to increase the 'safe' position.
4408 	 *
4409 	 * When reshaping backwards, we round in the opposite direction
4410 	 * and perform the reverse test:  next write position must not be
4411 	 * less than current safe position.
4412 	 *
4413 	 * In all this the minimum difference in data offsets
4414 	 * (conf->offset_diff - always positive) allows a bit of slack,
4415 	 * so next can be after 'safe', but not by more than offset_diff
4416 	 *
4417 	 * We need to prepare all the bios here before we start any IO
4418 	 * to ensure the size we choose is acceptable to all devices.
4419 	 * The means one for each copy for write-out and an extra one for
4420 	 * read-in.
4421 	 * We store the read-in bio in ->master_bio and the others in
4422 	 * ->devs[x].bio and ->devs[x].repl_bio.
4423 	 */
4424 	struct r10conf *conf = mddev->private;
4425 	struct r10bio *r10_bio;
4426 	sector_t next, safe, last;
4427 	int max_sectors;
4428 	int nr_sectors;
4429 	int s;
4430 	struct md_rdev *rdev;
4431 	int need_flush = 0;
4432 	struct bio *blist;
4433 	struct bio *bio, *read_bio;
4434 	int sectors_done = 0;
4435 	struct page **pages;
4436 
4437 	if (sector_nr == 0) {
4438 		/* If restarting in the middle, skip the initial sectors */
4439 		if (mddev->reshape_backwards &&
4440 		    conf->reshape_progress < raid10_size(mddev, 0, 0)) {
4441 			sector_nr = (raid10_size(mddev, 0, 0)
4442 				     - conf->reshape_progress);
4443 		} else if (!mddev->reshape_backwards &&
4444 			   conf->reshape_progress > 0)
4445 			sector_nr = conf->reshape_progress;
4446 		if (sector_nr) {
4447 			mddev->curr_resync_completed = sector_nr;
4448 			sysfs_notify_dirent_safe(mddev->sysfs_completed);
4449 			*skipped = 1;
4450 			return sector_nr;
4451 		}
4452 	}
4453 
4454 	/* We don't use sector_nr to track where we are up to
4455 	 * as that doesn't work well for ->reshape_backwards.
4456 	 * So just use ->reshape_progress.
4457 	 */
4458 	if (mddev->reshape_backwards) {
4459 		/* 'next' is the earliest device address that we might
4460 		 * write to for this chunk in the new layout
4461 		 */
4462 		next = first_dev_address(conf->reshape_progress - 1,
4463 					 &conf->geo);
4464 
4465 		/* 'safe' is the last device address that we might read from
4466 		 * in the old layout after a restart
4467 		 */
4468 		safe = last_dev_address(conf->reshape_safe - 1,
4469 					&conf->prev);
4470 
4471 		if (next + conf->offset_diff < safe)
4472 			need_flush = 1;
4473 
4474 		last = conf->reshape_progress - 1;
4475 		sector_nr = last & ~(sector_t)(conf->geo.chunk_mask
4476 					       & conf->prev.chunk_mask);
4477 		if (sector_nr + RESYNC_SECTORS < last)
4478 			sector_nr = last + 1 - RESYNC_SECTORS;
4479 	} else {
4480 		/* 'next' is after the last device address that we
4481 		 * might write to for this chunk in the new layout
4482 		 */
4483 		next = last_dev_address(conf->reshape_progress, &conf->geo);
4484 
4485 		/* 'safe' is the earliest device address that we might
4486 		 * read from in the old layout after a restart
4487 		 */
4488 		safe = first_dev_address(conf->reshape_safe, &conf->prev);
4489 
4490 		/* Need to update metadata if 'next' might be beyond 'safe'
4491 		 * as that would possibly corrupt data
4492 		 */
4493 		if (next > safe + conf->offset_diff)
4494 			need_flush = 1;
4495 
4496 		sector_nr = conf->reshape_progress;
4497 		last  = sector_nr | (conf->geo.chunk_mask
4498 				     & conf->prev.chunk_mask);
4499 
4500 		if (sector_nr + RESYNC_SECTORS <= last)
4501 			last = sector_nr + RESYNC_SECTORS - 1;
4502 	}
4503 
4504 	if (need_flush ||
4505 	    time_after(jiffies, conf->reshape_checkpoint + 10*HZ)) {
4506 		/* Need to update reshape_position in metadata */
4507 		wait_barrier(conf);
4508 		mddev->reshape_position = conf->reshape_progress;
4509 		if (mddev->reshape_backwards)
4510 			mddev->curr_resync_completed = raid10_size(mddev, 0, 0)
4511 				- conf->reshape_progress;
4512 		else
4513 			mddev->curr_resync_completed = conf->reshape_progress;
4514 		conf->reshape_checkpoint = jiffies;
4515 		set_bit(MD_SB_CHANGE_DEVS, &mddev->sb_flags);
4516 		md_wakeup_thread(mddev->thread);
4517 		wait_event(mddev->sb_wait, mddev->sb_flags == 0 ||
4518 			   test_bit(MD_RECOVERY_INTR, &mddev->recovery));
4519 		if (test_bit(MD_RECOVERY_INTR, &mddev->recovery)) {
4520 			allow_barrier(conf);
4521 			return sectors_done;
4522 		}
4523 		conf->reshape_safe = mddev->reshape_position;
4524 		allow_barrier(conf);
4525 	}
4526 
4527 	raise_barrier(conf, 0);
4528 read_more:
4529 	/* Now schedule reads for blocks from sector_nr to last */
4530 	r10_bio = raid10_alloc_init_r10buf(conf);
4531 	r10_bio->state = 0;
4532 	raise_barrier(conf, 1);
4533 	atomic_set(&r10_bio->remaining, 0);
4534 	r10_bio->mddev = mddev;
4535 	r10_bio->sector = sector_nr;
4536 	set_bit(R10BIO_IsReshape, &r10_bio->state);
4537 	r10_bio->sectors = last - sector_nr + 1;
4538 	rdev = read_balance(conf, r10_bio, &max_sectors);
4539 	BUG_ON(!test_bit(R10BIO_Previous, &r10_bio->state));
4540 
4541 	if (!rdev) {
4542 		/* Cannot read from here, so need to record bad blocks
4543 		 * on all the target devices.
4544 		 */
4545 		// FIXME
4546 		mempool_free(r10_bio, &conf->r10buf_pool);
4547 		set_bit(MD_RECOVERY_INTR, &mddev->recovery);
4548 		return sectors_done;
4549 	}
4550 
4551 	read_bio = bio_alloc_mddev(GFP_KERNEL, RESYNC_PAGES, mddev);
4552 
4553 	bio_set_dev(read_bio, rdev->bdev);
4554 	read_bio->bi_iter.bi_sector = (r10_bio->devs[r10_bio->read_slot].addr
4555 			       + rdev->data_offset);
4556 	read_bio->bi_private = r10_bio;
4557 	read_bio->bi_end_io = end_reshape_read;
4558 	bio_set_op_attrs(read_bio, REQ_OP_READ, 0);
4559 	read_bio->bi_flags &= (~0UL << BIO_RESET_BITS);
4560 	read_bio->bi_status = 0;
4561 	read_bio->bi_vcnt = 0;
4562 	read_bio->bi_iter.bi_size = 0;
4563 	r10_bio->master_bio = read_bio;
4564 	r10_bio->read_slot = r10_bio->devs[r10_bio->read_slot].devnum;
4565 
4566 	/*
4567 	 * Broadcast RESYNC message to other nodes, so all nodes would not
4568 	 * write to the region to avoid conflict.
4569 	*/
4570 	if (mddev_is_clustered(mddev) && conf->cluster_sync_high <= sector_nr) {
4571 		struct mdp_superblock_1 *sb = NULL;
4572 		int sb_reshape_pos = 0;
4573 
4574 		conf->cluster_sync_low = sector_nr;
4575 		conf->cluster_sync_high = sector_nr + CLUSTER_RESYNC_WINDOW_SECTORS;
4576 		sb = page_address(rdev->sb_page);
4577 		if (sb) {
4578 			sb_reshape_pos = le64_to_cpu(sb->reshape_position);
4579 			/*
4580 			 * Set cluster_sync_low again if next address for array
4581 			 * reshape is less than cluster_sync_low. Since we can't
4582 			 * update cluster_sync_low until it has finished reshape.
4583 			 */
4584 			if (sb_reshape_pos < conf->cluster_sync_low)
4585 				conf->cluster_sync_low = sb_reshape_pos;
4586 		}
4587 
4588 		md_cluster_ops->resync_info_update(mddev, conf->cluster_sync_low,
4589 							  conf->cluster_sync_high);
4590 	}
4591 
4592 	/* Now find the locations in the new layout */
4593 	__raid10_find_phys(&conf->geo, r10_bio);
4594 
4595 	blist = read_bio;
4596 	read_bio->bi_next = NULL;
4597 
4598 	rcu_read_lock();
4599 	for (s = 0; s < conf->copies*2; s++) {
4600 		struct bio *b;
4601 		int d = r10_bio->devs[s/2].devnum;
4602 		struct md_rdev *rdev2;
4603 		if (s&1) {
4604 			rdev2 = rcu_dereference(conf->mirrors[d].replacement);
4605 			b = r10_bio->devs[s/2].repl_bio;
4606 		} else {
4607 			rdev2 = rcu_dereference(conf->mirrors[d].rdev);
4608 			b = r10_bio->devs[s/2].bio;
4609 		}
4610 		if (!rdev2 || test_bit(Faulty, &rdev2->flags))
4611 			continue;
4612 
4613 		bio_set_dev(b, rdev2->bdev);
4614 		b->bi_iter.bi_sector = r10_bio->devs[s/2].addr +
4615 			rdev2->new_data_offset;
4616 		b->bi_end_io = end_reshape_write;
4617 		bio_set_op_attrs(b, REQ_OP_WRITE, 0);
4618 		b->bi_next = blist;
4619 		blist = b;
4620 	}
4621 
4622 	/* Now add as many pages as possible to all of these bios. */
4623 
4624 	nr_sectors = 0;
4625 	pages = get_resync_pages(r10_bio->devs[0].bio)->pages;
4626 	for (s = 0 ; s < max_sectors; s += PAGE_SIZE >> 9) {
4627 		struct page *page = pages[s / (PAGE_SIZE >> 9)];
4628 		int len = (max_sectors - s) << 9;
4629 		if (len > PAGE_SIZE)
4630 			len = PAGE_SIZE;
4631 		for (bio = blist; bio ; bio = bio->bi_next) {
4632 			/*
4633 			 * won't fail because the vec table is big enough
4634 			 * to hold all these pages
4635 			 */
4636 			bio_add_page(bio, page, len, 0);
4637 		}
4638 		sector_nr += len >> 9;
4639 		nr_sectors += len >> 9;
4640 	}
4641 	rcu_read_unlock();
4642 	r10_bio->sectors = nr_sectors;
4643 
4644 	/* Now submit the read */
4645 	md_sync_acct_bio(read_bio, r10_bio->sectors);
4646 	atomic_inc(&r10_bio->remaining);
4647 	read_bio->bi_next = NULL;
4648 	submit_bio_noacct(read_bio);
4649 	sectors_done += nr_sectors;
4650 	if (sector_nr <= last)
4651 		goto read_more;
4652 
4653 	lower_barrier(conf);
4654 
4655 	/* Now that we have done the whole section we can
4656 	 * update reshape_progress
4657 	 */
4658 	if (mddev->reshape_backwards)
4659 		conf->reshape_progress -= sectors_done;
4660 	else
4661 		conf->reshape_progress += sectors_done;
4662 
4663 	return sectors_done;
4664 }
4665 
4666 static void end_reshape_request(struct r10bio *r10_bio);
4667 static int handle_reshape_read_error(struct mddev *mddev,
4668 				     struct r10bio *r10_bio);
reshape_request_write(struct mddev *mddev, struct r10bio *r10_bio)4669 static void reshape_request_write(struct mddev *mddev, struct r10bio *r10_bio)
4670 {
4671 	/* Reshape read completed.  Hopefully we have a block
4672 	 * to write out.
4673 	 * If we got a read error then we do sync 1-page reads from
4674 	 * elsewhere until we find the data - or give up.
4675 	 */
4676 	struct r10conf *conf = mddev->private;
4677 	int s;
4678 
4679 	if (!test_bit(R10BIO_Uptodate, &r10_bio->state))
4680 		if (handle_reshape_read_error(mddev, r10_bio) < 0) {
4681 			/* Reshape has been aborted */
4682 			md_done_sync(mddev, r10_bio->sectors, 0);
4683 			return;
4684 		}
4685 
4686 	/* We definitely have the data in the pages, schedule the
4687 	 * writes.
4688 	 */
4689 	atomic_set(&r10_bio->remaining, 1);
4690 	for (s = 0; s < conf->copies*2; s++) {
4691 		struct bio *b;
4692 		int d = r10_bio->devs[s/2].devnum;
4693 		struct md_rdev *rdev;
4694 		rcu_read_lock();
4695 		if (s&1) {
4696 			rdev = rcu_dereference(conf->mirrors[d].replacement);
4697 			b = r10_bio->devs[s/2].repl_bio;
4698 		} else {
4699 			rdev = rcu_dereference(conf->mirrors[d].rdev);
4700 			b = r10_bio->devs[s/2].bio;
4701 		}
4702 		if (!rdev || test_bit(Faulty, &rdev->flags)) {
4703 			rcu_read_unlock();
4704 			continue;
4705 		}
4706 		atomic_inc(&rdev->nr_pending);
4707 		rcu_read_unlock();
4708 		md_sync_acct_bio(b, r10_bio->sectors);
4709 		atomic_inc(&r10_bio->remaining);
4710 		b->bi_next = NULL;
4711 		submit_bio_noacct(b);
4712 	}
4713 	end_reshape_request(r10_bio);
4714 }
4715 
end_reshape(struct r10conf *conf)4716 static void end_reshape(struct r10conf *conf)
4717 {
4718 	if (test_bit(MD_RECOVERY_INTR, &conf->mddev->recovery))
4719 		return;
4720 
4721 	spin_lock_irq(&conf->device_lock);
4722 	conf->prev = conf->geo;
4723 	md_finish_reshape(conf->mddev);
4724 	smp_wmb();
4725 	conf->reshape_progress = MaxSector;
4726 	conf->reshape_safe = MaxSector;
4727 	spin_unlock_irq(&conf->device_lock);
4728 
4729 	if (conf->mddev->queue)
4730 		raid10_set_io_opt(conf);
4731 	conf->fullsync = 0;
4732 }
4733 
raid10_update_reshape_pos(struct mddev *mddev)4734 static void raid10_update_reshape_pos(struct mddev *mddev)
4735 {
4736 	struct r10conf *conf = mddev->private;
4737 	sector_t lo, hi;
4738 
4739 	md_cluster_ops->resync_info_get(mddev, &lo, &hi);
4740 	if (((mddev->reshape_position <= hi) && (mddev->reshape_position >= lo))
4741 	    || mddev->reshape_position == MaxSector)
4742 		conf->reshape_progress = mddev->reshape_position;
4743 	else
4744 		WARN_ON_ONCE(1);
4745 }
4746 
handle_reshape_read_error(struct mddev *mddev, struct r10bio *r10_bio)4747 static int handle_reshape_read_error(struct mddev *mddev,
4748 				     struct r10bio *r10_bio)
4749 {
4750 	/* Use sync reads to get the blocks from somewhere else */
4751 	int sectors = r10_bio->sectors;
4752 	struct r10conf *conf = mddev->private;
4753 	struct r10bio *r10b;
4754 	int slot = 0;
4755 	int idx = 0;
4756 	struct page **pages;
4757 
4758 	r10b = kmalloc(struct_size(r10b, devs, conf->copies), GFP_NOIO);
4759 	if (!r10b) {
4760 		set_bit(MD_RECOVERY_INTR, &mddev->recovery);
4761 		return -ENOMEM;
4762 	}
4763 
4764 	/* reshape IOs share pages from .devs[0].bio */
4765 	pages = get_resync_pages(r10_bio->devs[0].bio)->pages;
4766 
4767 	r10b->sector = r10_bio->sector;
4768 	__raid10_find_phys(&conf->prev, r10b);
4769 
4770 	while (sectors) {
4771 		int s = sectors;
4772 		int success = 0;
4773 		int first_slot = slot;
4774 
4775 		if (s > (PAGE_SIZE >> 9))
4776 			s = PAGE_SIZE >> 9;
4777 
4778 		rcu_read_lock();
4779 		while (!success) {
4780 			int d = r10b->devs[slot].devnum;
4781 			struct md_rdev *rdev = rcu_dereference(conf->mirrors[d].rdev);
4782 			sector_t addr;
4783 			if (rdev == NULL ||
4784 			    test_bit(Faulty, &rdev->flags) ||
4785 			    !test_bit(In_sync, &rdev->flags))
4786 				goto failed;
4787 
4788 			addr = r10b->devs[slot].addr + idx * PAGE_SIZE;
4789 			atomic_inc(&rdev->nr_pending);
4790 			rcu_read_unlock();
4791 			success = sync_page_io(rdev,
4792 					       addr,
4793 					       s << 9,
4794 					       pages[idx],
4795 					       REQ_OP_READ, 0, false);
4796 			rdev_dec_pending(rdev, mddev);
4797 			rcu_read_lock();
4798 			if (success)
4799 				break;
4800 		failed:
4801 			slot++;
4802 			if (slot >= conf->copies)
4803 				slot = 0;
4804 			if (slot == first_slot)
4805 				break;
4806 		}
4807 		rcu_read_unlock();
4808 		if (!success) {
4809 			/* couldn't read this block, must give up */
4810 			set_bit(MD_RECOVERY_INTR,
4811 				&mddev->recovery);
4812 			kfree(r10b);
4813 			return -EIO;
4814 		}
4815 		sectors -= s;
4816 		idx++;
4817 	}
4818 	kfree(r10b);
4819 	return 0;
4820 }
4821 
end_reshape_write(struct bio *bio)4822 static void end_reshape_write(struct bio *bio)
4823 {
4824 	struct r10bio *r10_bio = get_resync_r10bio(bio);
4825 	struct mddev *mddev = r10_bio->mddev;
4826 	struct r10conf *conf = mddev->private;
4827 	int d;
4828 	int slot;
4829 	int repl;
4830 	struct md_rdev *rdev = NULL;
4831 
4832 	d = find_bio_disk(conf, r10_bio, bio, &slot, &repl);
4833 	if (repl)
4834 		rdev = conf->mirrors[d].replacement;
4835 	if (!rdev) {
4836 		smp_mb();
4837 		rdev = conf->mirrors[d].rdev;
4838 	}
4839 
4840 	if (bio->bi_status) {
4841 		/* FIXME should record badblock */
4842 		md_error(mddev, rdev);
4843 	}
4844 
4845 	rdev_dec_pending(rdev, mddev);
4846 	end_reshape_request(r10_bio);
4847 }
4848 
end_reshape_request(struct r10bio *r10_bio)4849 static void end_reshape_request(struct r10bio *r10_bio)
4850 {
4851 	if (!atomic_dec_and_test(&r10_bio->remaining))
4852 		return;
4853 	md_done_sync(r10_bio->mddev, r10_bio->sectors, 1);
4854 	bio_put(r10_bio->master_bio);
4855 	put_buf(r10_bio);
4856 }
4857 
raid10_finish_reshape(struct mddev *mddev)4858 static void raid10_finish_reshape(struct mddev *mddev)
4859 {
4860 	struct r10conf *conf = mddev->private;
4861 
4862 	if (test_bit(MD_RECOVERY_INTR, &mddev->recovery))
4863 		return;
4864 
4865 	if (mddev->delta_disks > 0) {
4866 		if (mddev->recovery_cp > mddev->resync_max_sectors) {
4867 			mddev->recovery_cp = mddev->resync_max_sectors;
4868 			set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
4869 		}
4870 		mddev->resync_max_sectors = mddev->array_sectors;
4871 	} else {
4872 		int d;
4873 		rcu_read_lock();
4874 		for (d = conf->geo.raid_disks ;
4875 		     d < conf->geo.raid_disks - mddev->delta_disks;
4876 		     d++) {
4877 			struct md_rdev *rdev = rcu_dereference(conf->mirrors[d].rdev);
4878 			if (rdev)
4879 				clear_bit(In_sync, &rdev->flags);
4880 			rdev = rcu_dereference(conf->mirrors[d].replacement);
4881 			if (rdev)
4882 				clear_bit(In_sync, &rdev->flags);
4883 		}
4884 		rcu_read_unlock();
4885 	}
4886 	mddev->layout = mddev->new_layout;
4887 	mddev->chunk_sectors = 1 << conf->geo.chunk_shift;
4888 	mddev->reshape_position = MaxSector;
4889 	mddev->delta_disks = 0;
4890 	mddev->reshape_backwards = 0;
4891 }
4892 
4893 static struct md_personality raid10_personality =
4894 {
4895 	.name		= "raid10",
4896 	.level		= 10,
4897 	.owner		= THIS_MODULE,
4898 	.make_request	= raid10_make_request,
4899 	.run		= raid10_run,
4900 	.free		= raid10_free,
4901 	.status		= raid10_status,
4902 	.error_handler	= raid10_error,
4903 	.hot_add_disk	= raid10_add_disk,
4904 	.hot_remove_disk= raid10_remove_disk,
4905 	.spare_active	= raid10_spare_active,
4906 	.sync_request	= raid10_sync_request,
4907 	.quiesce	= raid10_quiesce,
4908 	.size		= raid10_size,
4909 	.resize		= raid10_resize,
4910 	.takeover	= raid10_takeover,
4911 	.check_reshape	= raid10_check_reshape,
4912 	.start_reshape	= raid10_start_reshape,
4913 	.finish_reshape	= raid10_finish_reshape,
4914 	.update_reshape_pos = raid10_update_reshape_pos,
4915 };
4916 
raid_init(void)4917 static int __init raid_init(void)
4918 {
4919 	return register_md_personality(&raid10_personality);
4920 }
4921 
raid_exit(void)4922 static void raid_exit(void)
4923 {
4924 	unregister_md_personality(&raid10_personality);
4925 }
4926 
4927 module_init(raid_init);
4928 module_exit(raid_exit);
4929 MODULE_LICENSE("GPL");
4930 MODULE_DESCRIPTION("RAID10 (striped mirror) personality for MD");
4931 MODULE_ALIAS("md-personality-9"); /* RAID10 */
4932 MODULE_ALIAS("md-raid10");
4933 MODULE_ALIAS("md-level-10");
4934 
4935 module_param(max_queued_requests, int, S_IRUGO|S_IWUSR);
4936