xref: /linux/drivers/md/dm-raid.c (revision cfc4ca8986bb1f6182da6cd7bb57f228590b4643)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Copyright (C) 2010-2011 Neil Brown
4  * Copyright (C) 2010-2018 Red Hat, Inc. All rights reserved.
5  *
6  * This file is released under the GPL.
7  */
8 
9 #include <linux/slab.h>
10 #include <linux/module.h>
11 
12 #include "md.h"
13 #include "raid1.h"
14 #include "raid5.h"
15 #include "raid10.h"
16 #include "md-bitmap.h"
17 #include "dm-core.h"
18 
19 #include <linux/device-mapper.h>
20 
21 #define DM_MSG_PREFIX "raid"
22 #define	MAX_RAID_DEVICES	253 /* md-raid kernel limit */
23 
24 /*
25  * Minimum sectors of free reshape space per raid device
26  */
27 #define	MIN_FREE_RESHAPE_SPACE to_sector(4*4096)
28 
29 /*
30  * Minimum journal space 4 MiB in sectors.
31  */
32 #define	MIN_RAID456_JOURNAL_SPACE (4*2048)
33 
34 static bool devices_handle_discard_safely;
35 
36 /*
37  * The following flags are used by dm-raid to set up the array state.
38  * They must be cleared before md_run is called.
39  */
40 #define FirstUse 10		/* rdev flag */
41 
42 struct raid_dev {
43 	/*
44 	 * Two DM devices, one to hold metadata and one to hold the
45 	 * actual data/parity.	The reason for this is to not confuse
46 	 * ti->len and give more flexibility in altering size and
47 	 * characteristics.
48 	 *
49 	 * While it is possible for this device to be associated
50 	 * with a different physical device than the data_dev, it
51 	 * is intended for it to be the same.
52 	 *    |--------- Physical Device ---------|
53 	 *    |- meta_dev -|------ data_dev ------|
54 	 */
55 	struct dm_dev *meta_dev;
56 	struct dm_dev *data_dev;
57 	struct md_rdev rdev;
58 };
59 
60 /*
61  * Bits for establishing rs->ctr_flags
62  *
63  * 1 = no flag value
64  * 2 = flag with value
65  */
66 #define __CTR_FLAG_SYNC			0  /* 1 */ /* Not with raid0! */
67 #define __CTR_FLAG_NOSYNC		1  /* 1 */ /* Not with raid0! */
68 #define __CTR_FLAG_REBUILD		2  /* 2 */ /* Not with raid0! */
69 #define __CTR_FLAG_DAEMON_SLEEP		3  /* 2 */ /* Not with raid0! */
70 #define __CTR_FLAG_MIN_RECOVERY_RATE	4  /* 2 */ /* Not with raid0! */
71 #define __CTR_FLAG_MAX_RECOVERY_RATE	5  /* 2 */ /* Not with raid0! */
72 #define __CTR_FLAG_MAX_WRITE_BEHIND	6  /* 2 */ /* Only with raid1! */
73 #define __CTR_FLAG_WRITE_MOSTLY		7  /* 2 */ /* Only with raid1! */
74 #define __CTR_FLAG_STRIPE_CACHE		8  /* 2 */ /* Only with raid4/5/6! */
75 #define __CTR_FLAG_REGION_SIZE		9  /* 2 */ /* Not with raid0! */
76 #define __CTR_FLAG_RAID10_COPIES	10 /* 2 */ /* Only with raid10 */
77 #define __CTR_FLAG_RAID10_FORMAT	11 /* 2 */ /* Only with raid10 */
78 /* New for v1.9.0 */
79 #define __CTR_FLAG_DELTA_DISKS		12 /* 2 */ /* Only with reshapable raid1/4/5/6/10! */
80 #define __CTR_FLAG_DATA_OFFSET		13 /* 2 */ /* Only with reshapable raid4/5/6/10! */
81 #define __CTR_FLAG_RAID10_USE_NEAR_SETS 14 /* 2 */ /* Only with raid10! */
82 
83 /* New for v1.10.0 */
84 #define __CTR_FLAG_JOURNAL_DEV		15 /* 2 */ /* Only with raid4/5/6 (journal device)! */
85 
86 /* New for v1.11.1 */
87 #define __CTR_FLAG_JOURNAL_MODE		16 /* 2 */ /* Only with raid4/5/6 (journal mode)! */
88 
89 /*
90  * Flags for rs->ctr_flags field.
91  */
92 #define CTR_FLAG_SYNC			(1 << __CTR_FLAG_SYNC)
93 #define CTR_FLAG_NOSYNC			(1 << __CTR_FLAG_NOSYNC)
94 #define CTR_FLAG_REBUILD		(1 << __CTR_FLAG_REBUILD)
95 #define CTR_FLAG_DAEMON_SLEEP		(1 << __CTR_FLAG_DAEMON_SLEEP)
96 #define CTR_FLAG_MIN_RECOVERY_RATE	(1 << __CTR_FLAG_MIN_RECOVERY_RATE)
97 #define CTR_FLAG_MAX_RECOVERY_RATE	(1 << __CTR_FLAG_MAX_RECOVERY_RATE)
98 #define CTR_FLAG_MAX_WRITE_BEHIND	(1 << __CTR_FLAG_MAX_WRITE_BEHIND)
99 #define CTR_FLAG_WRITE_MOSTLY		(1 << __CTR_FLAG_WRITE_MOSTLY)
100 #define CTR_FLAG_STRIPE_CACHE		(1 << __CTR_FLAG_STRIPE_CACHE)
101 #define CTR_FLAG_REGION_SIZE		(1 << __CTR_FLAG_REGION_SIZE)
102 #define CTR_FLAG_RAID10_COPIES		(1 << __CTR_FLAG_RAID10_COPIES)
103 #define CTR_FLAG_RAID10_FORMAT		(1 << __CTR_FLAG_RAID10_FORMAT)
104 #define CTR_FLAG_DELTA_DISKS		(1 << __CTR_FLAG_DELTA_DISKS)
105 #define CTR_FLAG_DATA_OFFSET		(1 << __CTR_FLAG_DATA_OFFSET)
106 #define CTR_FLAG_RAID10_USE_NEAR_SETS	(1 << __CTR_FLAG_RAID10_USE_NEAR_SETS)
107 #define CTR_FLAG_JOURNAL_DEV		(1 << __CTR_FLAG_JOURNAL_DEV)
108 #define CTR_FLAG_JOURNAL_MODE		(1 << __CTR_FLAG_JOURNAL_MODE)
109 
110 /*
111  * Definitions of various constructor flags to
112  * be used in checks of valid / invalid flags
113  * per raid level.
114  */
115 /* Define all any sync flags */
116 #define	CTR_FLAGS_ANY_SYNC		(CTR_FLAG_SYNC | CTR_FLAG_NOSYNC)
117 
118 /* Define flags for options without argument (e.g. 'nosync') */
119 #define	CTR_FLAG_OPTIONS_NO_ARGS	(CTR_FLAGS_ANY_SYNC | \
120 					 CTR_FLAG_RAID10_USE_NEAR_SETS)
121 
122 /* Define flags for options with one argument (e.g. 'delta_disks +2') */
123 #define CTR_FLAG_OPTIONS_ONE_ARG (CTR_FLAG_REBUILD | \
124 				  CTR_FLAG_WRITE_MOSTLY | \
125 				  CTR_FLAG_DAEMON_SLEEP | \
126 				  CTR_FLAG_MIN_RECOVERY_RATE | \
127 				  CTR_FLAG_MAX_RECOVERY_RATE | \
128 				  CTR_FLAG_MAX_WRITE_BEHIND | \
129 				  CTR_FLAG_STRIPE_CACHE | \
130 				  CTR_FLAG_REGION_SIZE | \
131 				  CTR_FLAG_RAID10_COPIES | \
132 				  CTR_FLAG_RAID10_FORMAT | \
133 				  CTR_FLAG_DELTA_DISKS | \
134 				  CTR_FLAG_DATA_OFFSET | \
135 				  CTR_FLAG_JOURNAL_DEV | \
136 				  CTR_FLAG_JOURNAL_MODE)
137 
138 /* Valid options definitions per raid level... */
139 
140 /* "raid0" does only accept data offset */
141 #define RAID0_VALID_FLAGS	(CTR_FLAG_DATA_OFFSET)
142 
143 /* "raid1" does not accept stripe cache, data offset, delta_disks or any raid10 options */
144 #define RAID1_VALID_FLAGS	(CTR_FLAGS_ANY_SYNC | \
145 				 CTR_FLAG_REBUILD | \
146 				 CTR_FLAG_WRITE_MOSTLY | \
147 				 CTR_FLAG_DAEMON_SLEEP | \
148 				 CTR_FLAG_MIN_RECOVERY_RATE | \
149 				 CTR_FLAG_MAX_RECOVERY_RATE | \
150 				 CTR_FLAG_MAX_WRITE_BEHIND | \
151 				 CTR_FLAG_REGION_SIZE | \
152 				 CTR_FLAG_DELTA_DISKS | \
153 				 CTR_FLAG_DATA_OFFSET)
154 
155 /* "raid10" does not accept any raid1 or stripe cache options */
156 #define RAID10_VALID_FLAGS	(CTR_FLAGS_ANY_SYNC | \
157 				 CTR_FLAG_REBUILD | \
158 				 CTR_FLAG_DAEMON_SLEEP | \
159 				 CTR_FLAG_MIN_RECOVERY_RATE | \
160 				 CTR_FLAG_MAX_RECOVERY_RATE | \
161 				 CTR_FLAG_REGION_SIZE | \
162 				 CTR_FLAG_RAID10_COPIES | \
163 				 CTR_FLAG_RAID10_FORMAT | \
164 				 CTR_FLAG_DELTA_DISKS | \
165 				 CTR_FLAG_DATA_OFFSET | \
166 				 CTR_FLAG_RAID10_USE_NEAR_SETS)
167 
168 /*
169  * "raid4/5/6" do not accept any raid1 or raid10 specific options
170  *
171  * "raid6" does not accept "nosync", because it is not guaranteed
172  * that both parity and q-syndrome are being written properly with
173  * any writes
174  */
175 #define RAID45_VALID_FLAGS	(CTR_FLAGS_ANY_SYNC | \
176 				 CTR_FLAG_REBUILD | \
177 				 CTR_FLAG_DAEMON_SLEEP | \
178 				 CTR_FLAG_MIN_RECOVERY_RATE | \
179 				 CTR_FLAG_MAX_RECOVERY_RATE | \
180 				 CTR_FLAG_STRIPE_CACHE | \
181 				 CTR_FLAG_REGION_SIZE | \
182 				 CTR_FLAG_DELTA_DISKS | \
183 				 CTR_FLAG_DATA_OFFSET | \
184 				 CTR_FLAG_JOURNAL_DEV | \
185 				 CTR_FLAG_JOURNAL_MODE)
186 
187 #define RAID6_VALID_FLAGS	(CTR_FLAG_SYNC | \
188 				 CTR_FLAG_REBUILD | \
189 				 CTR_FLAG_DAEMON_SLEEP | \
190 				 CTR_FLAG_MIN_RECOVERY_RATE | \
191 				 CTR_FLAG_MAX_RECOVERY_RATE | \
192 				 CTR_FLAG_STRIPE_CACHE | \
193 				 CTR_FLAG_REGION_SIZE | \
194 				 CTR_FLAG_DELTA_DISKS | \
195 				 CTR_FLAG_DATA_OFFSET | \
196 				 CTR_FLAG_JOURNAL_DEV | \
197 				 CTR_FLAG_JOURNAL_MODE)
198 /* ...valid options definitions per raid level */
199 
200 /*
201  * Flags for rs->runtime_flags field
202  * (RT_FLAG prefix meaning "runtime flag")
203  *
204  * These are all internal and used to define runtime state,
205  * e.g. to prevent another resume from preresume processing
206  * the raid set all over again.
207  */
208 #define RT_FLAG_RS_PRERESUMED		0
209 #define RT_FLAG_RS_RESUMED		1
210 #define RT_FLAG_RS_BITMAP_LOADED	2
211 #define RT_FLAG_UPDATE_SBS		3
212 #define RT_FLAG_RESHAPE_RS		4
213 #define RT_FLAG_RS_SUSPENDED		5
214 #define RT_FLAG_RS_IN_SYNC		6
215 #define RT_FLAG_RS_RESYNCING		7
216 #define RT_FLAG_RS_GROW			8
217 #define RT_FLAG_RS_FROZEN		9
218 
219 /* Array elements of 64 bit needed for rebuild/failed disk bits */
220 #define DISKS_ARRAY_ELEMS ((MAX_RAID_DEVICES + (sizeof(uint64_t) * 8 - 1)) / sizeof(uint64_t) / 8)
221 
222 /*
223  * raid set level, layout and chunk sectors backup/restore
224  */
225 struct rs_layout {
226 	int new_level;
227 	int new_layout;
228 	int new_chunk_sectors;
229 };
230 
231 struct raid_set {
232 	struct dm_target *ti;
233 
234 	uint32_t stripe_cache_entries;
235 	unsigned long ctr_flags;
236 	unsigned long runtime_flags;
237 
238 	uint64_t rebuild_disks[DISKS_ARRAY_ELEMS];
239 
240 	int raid_disks;
241 	int delta_disks;
242 	int data_offset;
243 	int raid10_copies;
244 	int requested_bitmap_chunk_sectors;
245 
246 	struct mddev md;
247 	struct raid_type *raid_type;
248 
249 	sector_t array_sectors;
250 	sector_t dev_sectors;
251 
252 	/* Optional raid4/5/6 journal device */
253 	struct journal_dev {
254 		struct dm_dev *dev;
255 		struct md_rdev rdev;
256 		int mode;
257 	} journal_dev;
258 
259 	struct raid_dev dev[] __counted_by(raid_disks);
260 };
261 
262 static void rs_config_backup(struct raid_set *rs, struct rs_layout *l)
263 {
264 	struct mddev *mddev = &rs->md;
265 
266 	l->new_level = mddev->new_level;
267 	l->new_layout = mddev->new_layout;
268 	l->new_chunk_sectors = mddev->new_chunk_sectors;
269 }
270 
271 static void rs_config_restore(struct raid_set *rs, struct rs_layout *l)
272 {
273 	struct mddev *mddev = &rs->md;
274 
275 	mddev->new_level = l->new_level;
276 	mddev->new_layout = l->new_layout;
277 	mddev->new_chunk_sectors = l->new_chunk_sectors;
278 }
279 
280 /* raid10 algorithms (i.e. formats) */
281 #define	ALGORITHM_RAID10_DEFAULT	0
282 #define	ALGORITHM_RAID10_NEAR		1
283 #define	ALGORITHM_RAID10_OFFSET		2
284 #define	ALGORITHM_RAID10_FAR		3
285 
286 /* Supported raid types and properties. */
287 static struct raid_type {
288 	const char *name;		/* RAID algorithm. */
289 	const char *descr;		/* Descriptor text for logging. */
290 	const unsigned int parity_devs;	/* # of parity devices. */
291 	const unsigned int minimal_devs;/* minimal # of devices in set. */
292 	const unsigned int level;	/* RAID level. */
293 	const unsigned int algorithm;	/* RAID algorithm. */
294 } raid_types[] = {
295 	{"raid0",	  "raid0 (striping)",			    0, 2, 0,  0 /* NONE */},
296 	{"raid1",	  "raid1 (mirroring)",			    0, 2, 1,  0 /* NONE */},
297 	{"raid10_far",	  "raid10 far (striped mirrors)",	    0, 2, 10, ALGORITHM_RAID10_FAR},
298 	{"raid10_offset", "raid10 offset (striped mirrors)",	    0, 2, 10, ALGORITHM_RAID10_OFFSET},
299 	{"raid10_near",	  "raid10 near (striped mirrors)",	    0, 2, 10, ALGORITHM_RAID10_NEAR},
300 	{"raid10",	  "raid10 (striped mirrors)",		    0, 2, 10, ALGORITHM_RAID10_DEFAULT},
301 	{"raid4",	  "raid4 (dedicated first parity disk)",    1, 2, 5,  ALGORITHM_PARITY_0}, /* raid4 layout = raid5_0 */
302 	{"raid5_n",	  "raid5 (dedicated last parity disk)",	    1, 2, 5,  ALGORITHM_PARITY_N},
303 	{"raid5_ls",	  "raid5 (left symmetric)",		    1, 2, 5,  ALGORITHM_LEFT_SYMMETRIC},
304 	{"raid5_rs",	  "raid5 (right symmetric)",		    1, 2, 5,  ALGORITHM_RIGHT_SYMMETRIC},
305 	{"raid5_la",	  "raid5 (left asymmetric)",		    1, 2, 5,  ALGORITHM_LEFT_ASYMMETRIC},
306 	{"raid5_ra",	  "raid5 (right asymmetric)",		    1, 2, 5,  ALGORITHM_RIGHT_ASYMMETRIC},
307 	{"raid6_zr",	  "raid6 (zero restart)",		    2, 4, 6,  ALGORITHM_ROTATING_ZERO_RESTART},
308 	{"raid6_nr",	  "raid6 (N restart)",			    2, 4, 6,  ALGORITHM_ROTATING_N_RESTART},
309 	{"raid6_nc",	  "raid6 (N continue)",			    2, 4, 6,  ALGORITHM_ROTATING_N_CONTINUE},
310 	{"raid6_n_6",	  "raid6 (dedicated parity/Q n/6)",	    2, 4, 6,  ALGORITHM_PARITY_N_6},
311 	{"raid6_ls_6",	  "raid6 (left symmetric dedicated Q 6)",   2, 4, 6,  ALGORITHM_LEFT_SYMMETRIC_6},
312 	{"raid6_rs_6",	  "raid6 (right symmetric dedicated Q 6)",  2, 4, 6,  ALGORITHM_RIGHT_SYMMETRIC_6},
313 	{"raid6_la_6",	  "raid6 (left asymmetric dedicated Q 6)",  2, 4, 6,  ALGORITHM_LEFT_ASYMMETRIC_6},
314 	{"raid6_ra_6",	  "raid6 (right asymmetric dedicated Q 6)", 2, 4, 6,  ALGORITHM_RIGHT_ASYMMETRIC_6}
315 };
316 
317 /* True, if @v is in inclusive range [@min, @max] */
318 static bool __within_range(long v, long min, long max)
319 {
320 	return v >= min && v <= max;
321 }
322 
323 /* All table line arguments are defined here */
324 static struct arg_name_flag {
325 	const unsigned long flag;
326 	const char *name;
327 } __arg_name_flags[] = {
328 	{ CTR_FLAG_SYNC, "sync"},
329 	{ CTR_FLAG_NOSYNC, "nosync"},
330 	{ CTR_FLAG_REBUILD, "rebuild"},
331 	{ CTR_FLAG_DAEMON_SLEEP, "daemon_sleep"},
332 	{ CTR_FLAG_MIN_RECOVERY_RATE, "min_recovery_rate"},
333 	{ CTR_FLAG_MAX_RECOVERY_RATE, "max_recovery_rate"},
334 	{ CTR_FLAG_MAX_WRITE_BEHIND, "max_write_behind"},
335 	{ CTR_FLAG_WRITE_MOSTLY, "write_mostly"},
336 	{ CTR_FLAG_STRIPE_CACHE, "stripe_cache"},
337 	{ CTR_FLAG_REGION_SIZE, "region_size"},
338 	{ CTR_FLAG_RAID10_COPIES, "raid10_copies"},
339 	{ CTR_FLAG_RAID10_FORMAT, "raid10_format"},
340 	{ CTR_FLAG_DATA_OFFSET, "data_offset"},
341 	{ CTR_FLAG_DELTA_DISKS, "delta_disks"},
342 	{ CTR_FLAG_RAID10_USE_NEAR_SETS, "raid10_use_near_sets"},
343 	{ CTR_FLAG_JOURNAL_DEV, "journal_dev" },
344 	{ CTR_FLAG_JOURNAL_MODE, "journal_mode" },
345 };
346 
347 /* Return argument name string for given @flag */
348 static const char *dm_raid_arg_name_by_flag(const uint32_t flag)
349 {
350 	if (hweight32(flag) == 1) {
351 		struct arg_name_flag *anf = __arg_name_flags + ARRAY_SIZE(__arg_name_flags);
352 
353 		while (anf-- > __arg_name_flags)
354 			if (flag & anf->flag)
355 				return anf->name;
356 
357 	} else
358 		DMERR("%s called with more than one flag!", __func__);
359 
360 	return NULL;
361 }
362 
363 /* Define correlation of raid456 journal cache modes and dm-raid target line parameters */
364 static struct {
365 	const int mode;
366 	const char *param;
367 } _raid456_journal_mode[] = {
368 	{ R5C_JOURNAL_MODE_WRITE_THROUGH, "writethrough" },
369 	{ R5C_JOURNAL_MODE_WRITE_BACK,    "writeback" }
370 };
371 
372 /* Return MD raid4/5/6 journal mode for dm @journal_mode one */
373 static int dm_raid_journal_mode_to_md(const char *mode)
374 {
375 	int m = ARRAY_SIZE(_raid456_journal_mode);
376 
377 	while (m--)
378 		if (!strcasecmp(mode, _raid456_journal_mode[m].param))
379 			return _raid456_journal_mode[m].mode;
380 
381 	return -EINVAL;
382 }
383 
384 /* Return dm-raid raid4/5/6 journal mode string for @mode */
385 static const char *md_journal_mode_to_dm_raid(const int mode)
386 {
387 	int m = ARRAY_SIZE(_raid456_journal_mode);
388 
389 	while (m--)
390 		if (mode == _raid456_journal_mode[m].mode)
391 			return _raid456_journal_mode[m].param;
392 
393 	return "unknown";
394 }
395 
396 /*
397  * Bool helpers to test for various raid levels of a raid set.
398  * It's level as reported by the superblock rather than
399  * the requested raid_type passed to the constructor.
400  */
401 /* Return true, if raid set in @rs is raid0 */
402 static bool rs_is_raid0(struct raid_set *rs)
403 {
404 	return !rs->md.level;
405 }
406 
407 /* Return true, if raid set in @rs is raid1 */
408 static bool rs_is_raid1(struct raid_set *rs)
409 {
410 	return rs->md.level == 1;
411 }
412 
413 /* Return true, if raid set in @rs is raid10 */
414 static bool rs_is_raid10(struct raid_set *rs)
415 {
416 	return rs->md.level == 10;
417 }
418 
419 /* Return true, if raid set in @rs is level 6 */
420 static bool rs_is_raid6(struct raid_set *rs)
421 {
422 	return rs->md.level == 6;
423 }
424 
425 /* Return true, if raid set in @rs is level 4, 5 or 6 */
426 static bool rs_is_raid456(struct raid_set *rs)
427 {
428 	return __within_range(rs->md.level, 4, 6);
429 }
430 
431 /* Return true, if raid set in @rs is reshapable */
432 static bool __is_raid10_far(int layout);
433 static bool rs_is_reshapable(struct raid_set *rs)
434 {
435 	return rs_is_raid456(rs) ||
436 	       (rs_is_raid10(rs) && !__is_raid10_far(rs->md.new_layout));
437 }
438 
439 /* Return true, if raid set in @rs is recovering */
440 static bool rs_is_recovering(struct raid_set *rs)
441 {
442 	return rs->md.recovery_cp < rs->md.dev_sectors;
443 }
444 
445 /* Return true, if raid set in @rs is reshaping */
446 static bool rs_is_reshaping(struct raid_set *rs)
447 {
448 	return rs->md.reshape_position != MaxSector;
449 }
450 
451 /*
452  * bool helpers to test for various raid levels of a raid type @rt
453  */
454 
455 /* Return true, if raid type in @rt is raid0 */
456 static bool rt_is_raid0(struct raid_type *rt)
457 {
458 	return !rt->level;
459 }
460 
461 /* Return true, if raid type in @rt is raid1 */
462 static bool rt_is_raid1(struct raid_type *rt)
463 {
464 	return rt->level == 1;
465 }
466 
467 /* Return true, if raid type in @rt is raid10 */
468 static bool rt_is_raid10(struct raid_type *rt)
469 {
470 	return rt->level == 10;
471 }
472 
473 /* Return true, if raid type in @rt is raid4/5 */
474 static bool rt_is_raid45(struct raid_type *rt)
475 {
476 	return __within_range(rt->level, 4, 5);
477 }
478 
479 /* Return true, if raid type in @rt is raid6 */
480 static bool rt_is_raid6(struct raid_type *rt)
481 {
482 	return rt->level == 6;
483 }
484 
485 /* Return true, if raid type in @rt is raid4/5/6 */
486 static bool rt_is_raid456(struct raid_type *rt)
487 {
488 	return __within_range(rt->level, 4, 6);
489 }
490 /* END: raid level bools */
491 
492 /* Return valid ctr flags for the raid level of @rs */
493 static unsigned long __valid_flags(struct raid_set *rs)
494 {
495 	if (rt_is_raid0(rs->raid_type))
496 		return RAID0_VALID_FLAGS;
497 	else if (rt_is_raid1(rs->raid_type))
498 		return RAID1_VALID_FLAGS;
499 	else if (rt_is_raid10(rs->raid_type))
500 		return RAID10_VALID_FLAGS;
501 	else if (rt_is_raid45(rs->raid_type))
502 		return RAID45_VALID_FLAGS;
503 	else if (rt_is_raid6(rs->raid_type))
504 		return RAID6_VALID_FLAGS;
505 
506 	return 0;
507 }
508 
509 /*
510  * Check for valid flags set on @rs
511  *
512  * Has to be called after parsing of the ctr flags!
513  */
514 static int rs_check_for_valid_flags(struct raid_set *rs)
515 {
516 	if (rs->ctr_flags & ~__valid_flags(rs)) {
517 		rs->ti->error = "Invalid flags combination";
518 		return -EINVAL;
519 	}
520 
521 	return 0;
522 }
523 
524 /* MD raid10 bit definitions and helpers */
525 #define RAID10_OFFSET			(1 << 16) /* stripes with data copies area adjacent on devices */
526 #define RAID10_BROCKEN_USE_FAR_SETS	(1 << 17) /* Broken in raid10.c: use sets instead of whole stripe rotation */
527 #define RAID10_USE_FAR_SETS		(1 << 18) /* Use sets instead of whole stripe rotation */
528 #define RAID10_FAR_COPIES_SHIFT		8	  /* raid10 # far copies shift (2nd byte of layout) */
529 
530 /* Return md raid10 near copies for @layout */
531 static unsigned int __raid10_near_copies(int layout)
532 {
533 	return layout & 0xFF;
534 }
535 
536 /* Return md raid10 far copies for @layout */
537 static unsigned int __raid10_far_copies(int layout)
538 {
539 	return __raid10_near_copies(layout >> RAID10_FAR_COPIES_SHIFT);
540 }
541 
542 /* Return true if md raid10 offset for @layout */
543 static bool __is_raid10_offset(int layout)
544 {
545 	return !!(layout & RAID10_OFFSET);
546 }
547 
548 /* Return true if md raid10 near for @layout */
549 static bool __is_raid10_near(int layout)
550 {
551 	return !__is_raid10_offset(layout) && __raid10_near_copies(layout) > 1;
552 }
553 
554 /* Return true if md raid10 far for @layout */
555 static bool __is_raid10_far(int layout)
556 {
557 	return !__is_raid10_offset(layout) && __raid10_far_copies(layout) > 1;
558 }
559 
560 /* Return md raid10 layout string for @layout */
561 static const char *raid10_md_layout_to_format(int layout)
562 {
563 	/*
564 	 * Bit 16 stands for "offset"
565 	 * (i.e. adjacent stripes hold copies)
566 	 *
567 	 * Refer to MD's raid10.c for details
568 	 */
569 	if (__is_raid10_offset(layout))
570 		return "offset";
571 
572 	if (__raid10_near_copies(layout) > 1)
573 		return "near";
574 
575 	if (__raid10_far_copies(layout) > 1)
576 		return "far";
577 
578 	return "unknown";
579 }
580 
581 /* Return md raid10 algorithm for @name */
582 static int raid10_name_to_format(const char *name)
583 {
584 	if (!strcasecmp(name, "near"))
585 		return ALGORITHM_RAID10_NEAR;
586 	else if (!strcasecmp(name, "offset"))
587 		return ALGORITHM_RAID10_OFFSET;
588 	else if (!strcasecmp(name, "far"))
589 		return ALGORITHM_RAID10_FAR;
590 
591 	return -EINVAL;
592 }
593 
594 /* Return md raid10 copies for @layout */
595 static unsigned int raid10_md_layout_to_copies(int layout)
596 {
597 	return max(__raid10_near_copies(layout), __raid10_far_copies(layout));
598 }
599 
600 /* Return md raid10 format id for @format string */
601 static int raid10_format_to_md_layout(struct raid_set *rs,
602 				      unsigned int algorithm,
603 				      unsigned int copies)
604 {
605 	unsigned int n = 1, f = 1, r = 0;
606 
607 	/*
608 	 * MD resilienece flaw:
609 	 *
610 	 * enabling use_far_sets for far/offset formats causes copies
611 	 * to be colocated on the same devs together with their origins!
612 	 *
613 	 * -> disable it for now in the definition above
614 	 */
615 	if (algorithm == ALGORITHM_RAID10_DEFAULT ||
616 	    algorithm == ALGORITHM_RAID10_NEAR)
617 		n = copies;
618 
619 	else if (algorithm == ALGORITHM_RAID10_OFFSET) {
620 		f = copies;
621 		r = RAID10_OFFSET;
622 		if (!test_bit(__CTR_FLAG_RAID10_USE_NEAR_SETS, &rs->ctr_flags))
623 			r |= RAID10_USE_FAR_SETS;
624 
625 	} else if (algorithm == ALGORITHM_RAID10_FAR) {
626 		f = copies;
627 		if (!test_bit(__CTR_FLAG_RAID10_USE_NEAR_SETS, &rs->ctr_flags))
628 			r |= RAID10_USE_FAR_SETS;
629 
630 	} else
631 		return -EINVAL;
632 
633 	return r | (f << RAID10_FAR_COPIES_SHIFT) | n;
634 }
635 /* END: MD raid10 bit definitions and helpers */
636 
637 /* Check for any of the raid10 algorithms */
638 static bool __got_raid10(struct raid_type *rtp, const int layout)
639 {
640 	if (rtp->level == 10) {
641 		switch (rtp->algorithm) {
642 		case ALGORITHM_RAID10_DEFAULT:
643 		case ALGORITHM_RAID10_NEAR:
644 			return __is_raid10_near(layout);
645 		case ALGORITHM_RAID10_OFFSET:
646 			return __is_raid10_offset(layout);
647 		case ALGORITHM_RAID10_FAR:
648 			return __is_raid10_far(layout);
649 		default:
650 			break;
651 		}
652 	}
653 
654 	return false;
655 }
656 
657 /* Return raid_type for @name */
658 static struct raid_type *get_raid_type(const char *name)
659 {
660 	struct raid_type *rtp = raid_types + ARRAY_SIZE(raid_types);
661 
662 	while (rtp-- > raid_types)
663 		if (!strcasecmp(rtp->name, name))
664 			return rtp;
665 
666 	return NULL;
667 }
668 
669 /* Return raid_type for @name based derived from @level and @layout */
670 static struct raid_type *get_raid_type_by_ll(const int level, const int layout)
671 {
672 	struct raid_type *rtp = raid_types + ARRAY_SIZE(raid_types);
673 
674 	while (rtp-- > raid_types) {
675 		/* RAID10 special checks based on @layout flags/properties */
676 		if (rtp->level == level &&
677 		    (__got_raid10(rtp, layout) || rtp->algorithm == layout))
678 			return rtp;
679 	}
680 
681 	return NULL;
682 }
683 
684 /* Adjust rdev sectors */
685 static void rs_set_rdev_sectors(struct raid_set *rs)
686 {
687 	struct mddev *mddev = &rs->md;
688 	struct md_rdev *rdev;
689 
690 	/*
691 	 * raid10 sets rdev->sector to the device size, which
692 	 * is unintended in case of out-of-place reshaping
693 	 */
694 	rdev_for_each(rdev, mddev)
695 		if (!test_bit(Journal, &rdev->flags))
696 			rdev->sectors = mddev->dev_sectors;
697 }
698 
699 /*
700  * Change bdev capacity of @rs in case of a disk add/remove reshape
701  */
702 static void rs_set_capacity(struct raid_set *rs)
703 {
704 	struct gendisk *gendisk = dm_disk(dm_table_get_md(rs->ti->table));
705 
706 	set_capacity_and_notify(gendisk, rs->md.array_sectors);
707 }
708 
709 /*
710  * Set the mddev properties in @rs to the current
711  * ones retrieved from the freshest superblock
712  */
713 static void rs_set_cur(struct raid_set *rs)
714 {
715 	struct mddev *mddev = &rs->md;
716 
717 	mddev->new_level = mddev->level;
718 	mddev->new_layout = mddev->layout;
719 	mddev->new_chunk_sectors = mddev->chunk_sectors;
720 }
721 
722 /*
723  * Set the mddev properties in @rs to the new
724  * ones requested by the ctr
725  */
726 static void rs_set_new(struct raid_set *rs)
727 {
728 	struct mddev *mddev = &rs->md;
729 
730 	mddev->level = mddev->new_level;
731 	mddev->layout = mddev->new_layout;
732 	mddev->chunk_sectors = mddev->new_chunk_sectors;
733 	mddev->raid_disks = rs->raid_disks;
734 	mddev->delta_disks = 0;
735 }
736 
737 static struct raid_set *raid_set_alloc(struct dm_target *ti, struct raid_type *raid_type,
738 				       unsigned int raid_devs)
739 {
740 	unsigned int i;
741 	struct raid_set *rs;
742 
743 	if (raid_devs <= raid_type->parity_devs) {
744 		ti->error = "Insufficient number of devices";
745 		return ERR_PTR(-EINVAL);
746 	}
747 
748 	rs = kzalloc(struct_size(rs, dev, raid_devs), GFP_KERNEL);
749 	if (!rs) {
750 		ti->error = "Cannot allocate raid context";
751 		return ERR_PTR(-ENOMEM);
752 	}
753 
754 	if (mddev_init(&rs->md)) {
755 		kfree(rs);
756 		ti->error = "Cannot initialize raid context";
757 		return ERR_PTR(-ENOMEM);
758 	}
759 
760 	rs->raid_disks = raid_devs;
761 	rs->delta_disks = 0;
762 
763 	rs->ti = ti;
764 	rs->raid_type = raid_type;
765 	rs->stripe_cache_entries = 256;
766 	rs->md.raid_disks = raid_devs;
767 	rs->md.level = raid_type->level;
768 	rs->md.new_level = rs->md.level;
769 	rs->md.layout = raid_type->algorithm;
770 	rs->md.new_layout = rs->md.layout;
771 	rs->md.delta_disks = 0;
772 	rs->md.recovery_cp = MaxSector;
773 
774 	for (i = 0; i < raid_devs; i++)
775 		md_rdev_init(&rs->dev[i].rdev);
776 
777 	/*
778 	 * Remaining items to be initialized by further RAID params:
779 	 *  rs->md.persistent
780 	 *  rs->md.external
781 	 *  rs->md.chunk_sectors
782 	 *  rs->md.new_chunk_sectors
783 	 *  rs->md.dev_sectors
784 	 */
785 
786 	return rs;
787 }
788 
789 /* Free all @rs allocations */
790 static void raid_set_free(struct raid_set *rs)
791 {
792 	int i;
793 
794 	if (rs->journal_dev.dev) {
795 		md_rdev_clear(&rs->journal_dev.rdev);
796 		dm_put_device(rs->ti, rs->journal_dev.dev);
797 	}
798 
799 	for (i = 0; i < rs->raid_disks; i++) {
800 		if (rs->dev[i].meta_dev)
801 			dm_put_device(rs->ti, rs->dev[i].meta_dev);
802 		md_rdev_clear(&rs->dev[i].rdev);
803 		if (rs->dev[i].data_dev)
804 			dm_put_device(rs->ti, rs->dev[i].data_dev);
805 	}
806 
807 	mddev_destroy(&rs->md);
808 	kfree(rs);
809 }
810 
811 /*
812  * For every device we have two words
813  *  <meta_dev>: meta device name or '-' if missing
814  *  <data_dev>: data device name or '-' if missing
815  *
816  * The following are permitted:
817  *    - -
818  *    - <data_dev>
819  *    <meta_dev> <data_dev>
820  *
821  * The following is not allowed:
822  *    <meta_dev> -
823  *
824  * This code parses those words.  If there is a failure,
825  * the caller must use raid_set_free() to unwind the operations.
826  */
827 static int parse_dev_params(struct raid_set *rs, struct dm_arg_set *as)
828 {
829 	int i;
830 	int rebuild = 0;
831 	int metadata_available = 0;
832 	int r = 0;
833 	const char *arg;
834 
835 	/* Put off the number of raid devices argument to get to dev pairs */
836 	arg = dm_shift_arg(as);
837 	if (!arg)
838 		return -EINVAL;
839 
840 	for (i = 0; i < rs->raid_disks; i++) {
841 		rs->dev[i].rdev.raid_disk = i;
842 
843 		rs->dev[i].meta_dev = NULL;
844 		rs->dev[i].data_dev = NULL;
845 
846 		/*
847 		 * There are no offsets initially.
848 		 * Out of place reshape will set them accordingly.
849 		 */
850 		rs->dev[i].rdev.data_offset = 0;
851 		rs->dev[i].rdev.new_data_offset = 0;
852 		rs->dev[i].rdev.mddev = &rs->md;
853 
854 		arg = dm_shift_arg(as);
855 		if (!arg)
856 			return -EINVAL;
857 
858 		if (strcmp(arg, "-")) {
859 			r = dm_get_device(rs->ti, arg, dm_table_get_mode(rs->ti->table),
860 					  &rs->dev[i].meta_dev);
861 			if (r) {
862 				rs->ti->error = "RAID metadata device lookup failure";
863 				return r;
864 			}
865 
866 			rs->dev[i].rdev.sb_page = alloc_page(GFP_KERNEL);
867 			if (!rs->dev[i].rdev.sb_page) {
868 				rs->ti->error = "Failed to allocate superblock page";
869 				return -ENOMEM;
870 			}
871 		}
872 
873 		arg = dm_shift_arg(as);
874 		if (!arg)
875 			return -EINVAL;
876 
877 		if (!strcmp(arg, "-")) {
878 			if (!test_bit(In_sync, &rs->dev[i].rdev.flags) &&
879 			    (!rs->dev[i].rdev.recovery_offset)) {
880 				rs->ti->error = "Drive designated for rebuild not specified";
881 				return -EINVAL;
882 			}
883 
884 			if (rs->dev[i].meta_dev) {
885 				rs->ti->error = "No data device supplied with metadata device";
886 				return -EINVAL;
887 			}
888 
889 			continue;
890 		}
891 
892 		r = dm_get_device(rs->ti, arg, dm_table_get_mode(rs->ti->table),
893 				  &rs->dev[i].data_dev);
894 		if (r) {
895 			rs->ti->error = "RAID device lookup failure";
896 			return r;
897 		}
898 
899 		if (rs->dev[i].meta_dev) {
900 			metadata_available = 1;
901 			rs->dev[i].rdev.meta_bdev = rs->dev[i].meta_dev->bdev;
902 		}
903 		rs->dev[i].rdev.bdev = rs->dev[i].data_dev->bdev;
904 		list_add_tail(&rs->dev[i].rdev.same_set, &rs->md.disks);
905 		if (!test_bit(In_sync, &rs->dev[i].rdev.flags))
906 			rebuild++;
907 	}
908 
909 	if (rs->journal_dev.dev)
910 		list_add_tail(&rs->journal_dev.rdev.same_set, &rs->md.disks);
911 
912 	if (metadata_available) {
913 		rs->md.external = 0;
914 		rs->md.persistent = 1;
915 		rs->md.major_version = 2;
916 	} else if (rebuild && !rs->md.recovery_cp) {
917 		/*
918 		 * Without metadata, we will not be able to tell if the array
919 		 * is in-sync or not - we must assume it is not.  Therefore,
920 		 * it is impossible to rebuild a drive.
921 		 *
922 		 * Even if there is metadata, the on-disk information may
923 		 * indicate that the array is not in-sync and it will then
924 		 * fail at that time.
925 		 *
926 		 * User could specify 'nosync' option if desperate.
927 		 */
928 		rs->ti->error = "Unable to rebuild drive while array is not in-sync";
929 		return -EINVAL;
930 	}
931 
932 	return 0;
933 }
934 
935 /*
936  * validate_region_size
937  * @rs
938  * @region_size:  region size in sectors.  If 0, pick a size (4MiB default).
939  *
940  * Set rs->md.bitmap_info.chunksize (which really refers to 'region size').
941  * Ensure that (ti->len/region_size < 2^21) - required by MD bitmap.
942  *
943  * Returns: 0 on success, -EINVAL on failure.
944  */
945 static int validate_region_size(struct raid_set *rs, unsigned long region_size)
946 {
947 	unsigned long min_region_size = rs->ti->len / (1 << 21);
948 
949 	if (rs_is_raid0(rs))
950 		return 0;
951 
952 	if (!region_size) {
953 		/*
954 		 * Choose a reasonable default.	 All figures in sectors.
955 		 */
956 		if (min_region_size > (1 << 13)) {
957 			/* If not a power of 2, make it the next power of 2 */
958 			region_size = roundup_pow_of_two(min_region_size);
959 			DMINFO("Choosing default region size of %lu sectors",
960 			       region_size);
961 		} else {
962 			DMINFO("Choosing default region size of 4MiB");
963 			region_size = 1 << 13; /* sectors */
964 		}
965 	} else {
966 		/*
967 		 * Validate user-supplied value.
968 		 */
969 		if (region_size > rs->ti->len) {
970 			rs->ti->error = "Supplied region size is too large";
971 			return -EINVAL;
972 		}
973 
974 		if (region_size < min_region_size) {
975 			DMERR("Supplied region_size (%lu sectors) below minimum (%lu)",
976 			      region_size, min_region_size);
977 			rs->ti->error = "Supplied region size is too small";
978 			return -EINVAL;
979 		}
980 
981 		if (!is_power_of_2(region_size)) {
982 			rs->ti->error = "Region size is not a power of 2";
983 			return -EINVAL;
984 		}
985 
986 		if (region_size < rs->md.chunk_sectors) {
987 			rs->ti->error = "Region size is smaller than the chunk size";
988 			return -EINVAL;
989 		}
990 	}
991 
992 	/*
993 	 * Convert sectors to bytes.
994 	 */
995 	rs->md.bitmap_info.chunksize = to_bytes(region_size);
996 
997 	return 0;
998 }
999 
1000 /*
1001  * validate_raid_redundancy
1002  * @rs
1003  *
1004  * Determine if there are enough devices in the array that haven't
1005  * failed (or are being rebuilt) to form a usable array.
1006  *
1007  * Returns: 0 on success, -EINVAL on failure.
1008  */
1009 static int validate_raid_redundancy(struct raid_set *rs)
1010 {
1011 	unsigned int i, rebuild_cnt = 0;
1012 	unsigned int rebuilds_per_group = 0, copies, raid_disks;
1013 	unsigned int group_size, last_group_start;
1014 
1015 	for (i = 0; i < rs->raid_disks; i++)
1016 		if (!test_bit(FirstUse, &rs->dev[i].rdev.flags) &&
1017 		    ((!test_bit(In_sync, &rs->dev[i].rdev.flags) ||
1018 		      !rs->dev[i].rdev.sb_page)))
1019 			rebuild_cnt++;
1020 
1021 	switch (rs->md.level) {
1022 	case 0:
1023 		break;
1024 	case 1:
1025 		if (rebuild_cnt >= rs->md.raid_disks)
1026 			goto too_many;
1027 		break;
1028 	case 4:
1029 	case 5:
1030 	case 6:
1031 		if (rebuild_cnt > rs->raid_type->parity_devs)
1032 			goto too_many;
1033 		break;
1034 	case 10:
1035 		copies = raid10_md_layout_to_copies(rs->md.new_layout);
1036 		if (copies < 2) {
1037 			DMERR("Bogus raid10 data copies < 2!");
1038 			return -EINVAL;
1039 		}
1040 
1041 		if (rebuild_cnt < copies)
1042 			break;
1043 
1044 		/*
1045 		 * It is possible to have a higher rebuild count for RAID10,
1046 		 * as long as the failed devices occur in different mirror
1047 		 * groups (i.e. different stripes).
1048 		 *
1049 		 * When checking "near" format, make sure no adjacent devices
1050 		 * have failed beyond what can be handled.  In addition to the
1051 		 * simple case where the number of devices is a multiple of the
1052 		 * number of copies, we must also handle cases where the number
1053 		 * of devices is not a multiple of the number of copies.
1054 		 * E.g.	   dev1 dev2 dev3 dev4 dev5
1055 		 *	    A	 A    B	   B	C
1056 		 *	    C	 D    D	   E	E
1057 		 */
1058 		raid_disks = min(rs->raid_disks, rs->md.raid_disks);
1059 		if (__is_raid10_near(rs->md.new_layout)) {
1060 			for (i = 0; i < raid_disks; i++) {
1061 				if (!(i % copies))
1062 					rebuilds_per_group = 0;
1063 				if ((!rs->dev[i].rdev.sb_page ||
1064 				    !test_bit(In_sync, &rs->dev[i].rdev.flags)) &&
1065 				    (++rebuilds_per_group >= copies))
1066 					goto too_many;
1067 			}
1068 			break;
1069 		}
1070 
1071 		/*
1072 		 * When checking "far" and "offset" formats, we need to ensure
1073 		 * that the device that holds its copy is not also dead or
1074 		 * being rebuilt.  (Note that "far" and "offset" formats only
1075 		 * support two copies right now.  These formats also only ever
1076 		 * use the 'use_far_sets' variant.)
1077 		 *
1078 		 * This check is somewhat complicated by the need to account
1079 		 * for arrays that are not a multiple of (far) copies.	This
1080 		 * results in the need to treat the last (potentially larger)
1081 		 * set differently.
1082 		 */
1083 		group_size = (raid_disks / copies);
1084 		last_group_start = (raid_disks / group_size) - 1;
1085 		last_group_start *= group_size;
1086 		for (i = 0; i < raid_disks; i++) {
1087 			if (!(i % copies) && !(i > last_group_start))
1088 				rebuilds_per_group = 0;
1089 			if ((!rs->dev[i].rdev.sb_page ||
1090 			     !test_bit(In_sync, &rs->dev[i].rdev.flags)) &&
1091 			    (++rebuilds_per_group >= copies))
1092 				goto too_many;
1093 		}
1094 		break;
1095 	default:
1096 		if (rebuild_cnt)
1097 			return -EINVAL;
1098 	}
1099 
1100 	return 0;
1101 
1102 too_many:
1103 	return -EINVAL;
1104 }
1105 
1106 /*
1107  * Possible arguments are...
1108  *	<chunk_size> [optional_args]
1109  *
1110  * Argument definitions
1111  *    <chunk_size>			The number of sectors per disk that
1112  *					will form the "stripe"
1113  *    [[no]sync]			Force or prevent recovery of the
1114  *					entire array
1115  *    [rebuild <idx>]			Rebuild the drive indicated by the index
1116  *    [daemon_sleep <ms>]		Time between bitmap daemon work to
1117  *					clear bits
1118  *    [min_recovery_rate <kB/sec/disk>]	Throttle RAID initialization
1119  *    [max_recovery_rate <kB/sec/disk>]	Throttle RAID initialization
1120  *    [write_mostly <idx>]		Indicate a write mostly drive via index
1121  *    [max_write_behind <sectors>]	See '-write-behind=' (man mdadm)
1122  *    [stripe_cache <sectors>]		Stripe cache size for higher RAIDs
1123  *    [region_size <sectors>]		Defines granularity of bitmap
1124  *    [journal_dev <dev>]		raid4/5/6 journaling deviice
1125  *					(i.e. write hole closing log)
1126  *
1127  * RAID10-only options:
1128  *    [raid10_copies <# copies>]	Number of copies.  (Default: 2)
1129  *    [raid10_format <near|far|offset>] Layout algorithm.  (Default: near)
1130  */
1131 static int parse_raid_params(struct raid_set *rs, struct dm_arg_set *as,
1132 			     unsigned int num_raid_params)
1133 {
1134 	int value, raid10_format = ALGORITHM_RAID10_DEFAULT;
1135 	unsigned int raid10_copies = 2;
1136 	unsigned int i, write_mostly = 0;
1137 	unsigned int region_size = 0;
1138 	sector_t max_io_len;
1139 	const char *arg, *key;
1140 	struct raid_dev *rd;
1141 	struct raid_type *rt = rs->raid_type;
1142 
1143 	arg = dm_shift_arg(as);
1144 	num_raid_params--; /* Account for chunk_size argument */
1145 
1146 	if (kstrtoint(arg, 10, &value) < 0) {
1147 		rs->ti->error = "Bad numerical argument given for chunk_size";
1148 		return -EINVAL;
1149 	}
1150 
1151 	/*
1152 	 * First, parse the in-order required arguments
1153 	 * "chunk_size" is the only argument of this type.
1154 	 */
1155 	if (rt_is_raid1(rt)) {
1156 		if (value)
1157 			DMERR("Ignoring chunk size parameter for RAID 1");
1158 		value = 0;
1159 	} else if (!is_power_of_2(value)) {
1160 		rs->ti->error = "Chunk size must be a power of 2";
1161 		return -EINVAL;
1162 	} else if (value < 8) {
1163 		rs->ti->error = "Chunk size value is too small";
1164 		return -EINVAL;
1165 	}
1166 
1167 	rs->md.new_chunk_sectors = rs->md.chunk_sectors = value;
1168 
1169 	/*
1170 	 * We set each individual device as In_sync with a completed
1171 	 * 'recovery_offset'.  If there has been a device failure or
1172 	 * replacement then one of the following cases applies:
1173 	 *
1174 	 *   1) User specifies 'rebuild'.
1175 	 *	- Device is reset when param is read.
1176 	 *   2) A new device is supplied.
1177 	 *	- No matching superblock found, resets device.
1178 	 *   3) Device failure was transient and returns on reload.
1179 	 *	- Failure noticed, resets device for bitmap replay.
1180 	 *   4) Device hadn't completed recovery after previous failure.
1181 	 *	- Superblock is read and overrides recovery_offset.
1182 	 *
1183 	 * What is found in the superblocks of the devices is always
1184 	 * authoritative, unless 'rebuild' or '[no]sync' was specified.
1185 	 */
1186 	for (i = 0; i < rs->raid_disks; i++) {
1187 		set_bit(In_sync, &rs->dev[i].rdev.flags);
1188 		rs->dev[i].rdev.recovery_offset = MaxSector;
1189 	}
1190 
1191 	/*
1192 	 * Second, parse the unordered optional arguments
1193 	 */
1194 	for (i = 0; i < num_raid_params; i++) {
1195 		key = dm_shift_arg(as);
1196 		if (!key) {
1197 			rs->ti->error = "Not enough raid parameters given";
1198 			return -EINVAL;
1199 		}
1200 
1201 		if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_NOSYNC))) {
1202 			if (test_and_set_bit(__CTR_FLAG_NOSYNC, &rs->ctr_flags)) {
1203 				rs->ti->error = "Only one 'nosync' argument allowed";
1204 				return -EINVAL;
1205 			}
1206 			continue;
1207 		}
1208 		if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_SYNC))) {
1209 			if (test_and_set_bit(__CTR_FLAG_SYNC, &rs->ctr_flags)) {
1210 				rs->ti->error = "Only one 'sync' argument allowed";
1211 				return -EINVAL;
1212 			}
1213 			continue;
1214 		}
1215 		if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_RAID10_USE_NEAR_SETS))) {
1216 			if (test_and_set_bit(__CTR_FLAG_RAID10_USE_NEAR_SETS, &rs->ctr_flags)) {
1217 				rs->ti->error = "Only one 'raid10_use_new_sets' argument allowed";
1218 				return -EINVAL;
1219 			}
1220 			continue;
1221 		}
1222 
1223 		arg = dm_shift_arg(as);
1224 		i++; /* Account for the argument pairs */
1225 		if (!arg) {
1226 			rs->ti->error = "Wrong number of raid parameters given";
1227 			return -EINVAL;
1228 		}
1229 
1230 		/*
1231 		 * Parameters that take a string value are checked here.
1232 		 */
1233 		/* "raid10_format {near|offset|far} */
1234 		if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_RAID10_FORMAT))) {
1235 			if (test_and_set_bit(__CTR_FLAG_RAID10_FORMAT, &rs->ctr_flags)) {
1236 				rs->ti->error = "Only one 'raid10_format' argument pair allowed";
1237 				return -EINVAL;
1238 			}
1239 			if (!rt_is_raid10(rt)) {
1240 				rs->ti->error = "'raid10_format' is an invalid parameter for this RAID type";
1241 				return -EINVAL;
1242 			}
1243 			raid10_format = raid10_name_to_format(arg);
1244 			if (raid10_format < 0) {
1245 				rs->ti->error = "Invalid 'raid10_format' value given";
1246 				return raid10_format;
1247 			}
1248 			continue;
1249 		}
1250 
1251 		/* "journal_dev <dev>" */
1252 		if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_JOURNAL_DEV))) {
1253 			int r;
1254 			struct md_rdev *jdev;
1255 
1256 			if (test_and_set_bit(__CTR_FLAG_JOURNAL_DEV, &rs->ctr_flags)) {
1257 				rs->ti->error = "Only one raid4/5/6 set journaling device allowed";
1258 				return -EINVAL;
1259 			}
1260 			if (!rt_is_raid456(rt)) {
1261 				rs->ti->error = "'journal_dev' is an invalid parameter for this RAID type";
1262 				return -EINVAL;
1263 			}
1264 			r = dm_get_device(rs->ti, arg, dm_table_get_mode(rs->ti->table),
1265 					  &rs->journal_dev.dev);
1266 			if (r) {
1267 				rs->ti->error = "raid4/5/6 journal device lookup failure";
1268 				return r;
1269 			}
1270 			jdev = &rs->journal_dev.rdev;
1271 			md_rdev_init(jdev);
1272 			jdev->mddev = &rs->md;
1273 			jdev->bdev = rs->journal_dev.dev->bdev;
1274 			jdev->sectors = bdev_nr_sectors(jdev->bdev);
1275 			if (jdev->sectors < MIN_RAID456_JOURNAL_SPACE) {
1276 				rs->ti->error = "No space for raid4/5/6 journal";
1277 				return -ENOSPC;
1278 			}
1279 			rs->journal_dev.mode = R5C_JOURNAL_MODE_WRITE_THROUGH;
1280 			set_bit(Journal, &jdev->flags);
1281 			continue;
1282 		}
1283 
1284 		/* "journal_mode <mode>" ("journal_dev" mandatory!) */
1285 		if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_JOURNAL_MODE))) {
1286 			int r;
1287 
1288 			if (!test_bit(__CTR_FLAG_JOURNAL_DEV, &rs->ctr_flags)) {
1289 				rs->ti->error = "raid4/5/6 'journal_mode' is invalid without 'journal_dev'";
1290 				return -EINVAL;
1291 			}
1292 			if (test_and_set_bit(__CTR_FLAG_JOURNAL_MODE, &rs->ctr_flags)) {
1293 				rs->ti->error = "Only one raid4/5/6 'journal_mode' argument allowed";
1294 				return -EINVAL;
1295 			}
1296 			r = dm_raid_journal_mode_to_md(arg);
1297 			if (r < 0) {
1298 				rs->ti->error = "Invalid 'journal_mode' argument";
1299 				return r;
1300 			}
1301 			rs->journal_dev.mode = r;
1302 			continue;
1303 		}
1304 
1305 		/*
1306 		 * Parameters with number values from here on.
1307 		 */
1308 		if (kstrtoint(arg, 10, &value) < 0) {
1309 			rs->ti->error = "Bad numerical argument given in raid params";
1310 			return -EINVAL;
1311 		}
1312 
1313 		if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_REBUILD))) {
1314 			/*
1315 			 * "rebuild" is being passed in by userspace to provide
1316 			 * indexes of replaced devices and to set up additional
1317 			 * devices on raid level takeover.
1318 			 */
1319 			if (!__within_range(value, 0, rs->raid_disks - 1)) {
1320 				rs->ti->error = "Invalid rebuild index given";
1321 				return -EINVAL;
1322 			}
1323 
1324 			if (test_and_set_bit(value, (void *) rs->rebuild_disks)) {
1325 				rs->ti->error = "rebuild for this index already given";
1326 				return -EINVAL;
1327 			}
1328 
1329 			rd = rs->dev + value;
1330 			clear_bit(In_sync, &rd->rdev.flags);
1331 			clear_bit(Faulty, &rd->rdev.flags);
1332 			rd->rdev.recovery_offset = 0;
1333 			set_bit(__CTR_FLAG_REBUILD, &rs->ctr_flags);
1334 		} else if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_WRITE_MOSTLY))) {
1335 			if (!rt_is_raid1(rt)) {
1336 				rs->ti->error = "write_mostly option is only valid for RAID1";
1337 				return -EINVAL;
1338 			}
1339 
1340 			if (!__within_range(value, 0, rs->md.raid_disks - 1)) {
1341 				rs->ti->error = "Invalid write_mostly index given";
1342 				return -EINVAL;
1343 			}
1344 
1345 			write_mostly++;
1346 			set_bit(WriteMostly, &rs->dev[value].rdev.flags);
1347 			set_bit(__CTR_FLAG_WRITE_MOSTLY, &rs->ctr_flags);
1348 		} else if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_MAX_WRITE_BEHIND))) {
1349 			if (!rt_is_raid1(rt)) {
1350 				rs->ti->error = "max_write_behind option is only valid for RAID1";
1351 				return -EINVAL;
1352 			}
1353 
1354 			if (test_and_set_bit(__CTR_FLAG_MAX_WRITE_BEHIND, &rs->ctr_flags)) {
1355 				rs->ti->error = "Only one max_write_behind argument pair allowed";
1356 				return -EINVAL;
1357 			}
1358 
1359 			/*
1360 			 * In device-mapper, we specify things in sectors, but
1361 			 * MD records this value in kB
1362 			 */
1363 			if (value < 0 || value / 2 > COUNTER_MAX) {
1364 				rs->ti->error = "Max write-behind limit out of range";
1365 				return -EINVAL;
1366 			}
1367 
1368 			rs->md.bitmap_info.max_write_behind = value / 2;
1369 		} else if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_DAEMON_SLEEP))) {
1370 			if (test_and_set_bit(__CTR_FLAG_DAEMON_SLEEP, &rs->ctr_flags)) {
1371 				rs->ti->error = "Only one daemon_sleep argument pair allowed";
1372 				return -EINVAL;
1373 			}
1374 			if (value < 0) {
1375 				rs->ti->error = "daemon sleep period out of range";
1376 				return -EINVAL;
1377 			}
1378 			rs->md.bitmap_info.daemon_sleep = value;
1379 		} else if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_DATA_OFFSET))) {
1380 			/* Userspace passes new data_offset after having extended the data image LV */
1381 			if (test_and_set_bit(__CTR_FLAG_DATA_OFFSET, &rs->ctr_flags)) {
1382 				rs->ti->error = "Only one data_offset argument pair allowed";
1383 				return -EINVAL;
1384 			}
1385 			/* Ensure sensible data offset */
1386 			if (value < 0 ||
1387 			    (value && (value < MIN_FREE_RESHAPE_SPACE || value % to_sector(PAGE_SIZE)))) {
1388 				rs->ti->error = "Bogus data_offset value";
1389 				return -EINVAL;
1390 			}
1391 			rs->data_offset = value;
1392 		} else if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_DELTA_DISKS))) {
1393 			/* Define the +/-# of disks to add to/remove from the given raid set */
1394 			if (test_and_set_bit(__CTR_FLAG_DELTA_DISKS, &rs->ctr_flags)) {
1395 				rs->ti->error = "Only one delta_disks argument pair allowed";
1396 				return -EINVAL;
1397 			}
1398 			/* Ensure MAX_RAID_DEVICES and raid type minimal_devs! */
1399 			if (!__within_range(abs(value), 1, MAX_RAID_DEVICES - rt->minimal_devs)) {
1400 				rs->ti->error = "Too many delta_disk requested";
1401 				return -EINVAL;
1402 			}
1403 
1404 			rs->delta_disks = value;
1405 		} else if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_STRIPE_CACHE))) {
1406 			if (test_and_set_bit(__CTR_FLAG_STRIPE_CACHE, &rs->ctr_flags)) {
1407 				rs->ti->error = "Only one stripe_cache argument pair allowed";
1408 				return -EINVAL;
1409 			}
1410 
1411 			if (!rt_is_raid456(rt)) {
1412 				rs->ti->error = "Inappropriate argument: stripe_cache";
1413 				return -EINVAL;
1414 			}
1415 
1416 			if (value < 0) {
1417 				rs->ti->error = "Bogus stripe cache entries value";
1418 				return -EINVAL;
1419 			}
1420 			rs->stripe_cache_entries = value;
1421 		} else if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_MIN_RECOVERY_RATE))) {
1422 			if (test_and_set_bit(__CTR_FLAG_MIN_RECOVERY_RATE, &rs->ctr_flags)) {
1423 				rs->ti->error = "Only one min_recovery_rate argument pair allowed";
1424 				return -EINVAL;
1425 			}
1426 
1427 			if (value < 0) {
1428 				rs->ti->error = "min_recovery_rate out of range";
1429 				return -EINVAL;
1430 			}
1431 			rs->md.sync_speed_min = value;
1432 		} else if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_MAX_RECOVERY_RATE))) {
1433 			if (test_and_set_bit(__CTR_FLAG_MAX_RECOVERY_RATE, &rs->ctr_flags)) {
1434 				rs->ti->error = "Only one max_recovery_rate argument pair allowed";
1435 				return -EINVAL;
1436 			}
1437 
1438 			if (value < 0) {
1439 				rs->ti->error = "max_recovery_rate out of range";
1440 				return -EINVAL;
1441 			}
1442 			rs->md.sync_speed_max = value;
1443 		} else if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_REGION_SIZE))) {
1444 			if (test_and_set_bit(__CTR_FLAG_REGION_SIZE, &rs->ctr_flags)) {
1445 				rs->ti->error = "Only one region_size argument pair allowed";
1446 				return -EINVAL;
1447 			}
1448 
1449 			region_size = value;
1450 			rs->requested_bitmap_chunk_sectors = value;
1451 		} else if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_RAID10_COPIES))) {
1452 			if (test_and_set_bit(__CTR_FLAG_RAID10_COPIES, &rs->ctr_flags)) {
1453 				rs->ti->error = "Only one raid10_copies argument pair allowed";
1454 				return -EINVAL;
1455 			}
1456 
1457 			if (!__within_range(value, 2, rs->md.raid_disks)) {
1458 				rs->ti->error = "Bad value for 'raid10_copies'";
1459 				return -EINVAL;
1460 			}
1461 
1462 			raid10_copies = value;
1463 		} else {
1464 			DMERR("Unable to parse RAID parameter: %s", key);
1465 			rs->ti->error = "Unable to parse RAID parameter";
1466 			return -EINVAL;
1467 		}
1468 	}
1469 
1470 	if (test_bit(__CTR_FLAG_SYNC, &rs->ctr_flags) &&
1471 	    test_bit(__CTR_FLAG_NOSYNC, &rs->ctr_flags)) {
1472 		rs->ti->error = "sync and nosync are mutually exclusive";
1473 		return -EINVAL;
1474 	}
1475 
1476 	if (test_bit(__CTR_FLAG_REBUILD, &rs->ctr_flags) &&
1477 	    (test_bit(__CTR_FLAG_SYNC, &rs->ctr_flags) ||
1478 	     test_bit(__CTR_FLAG_NOSYNC, &rs->ctr_flags))) {
1479 		rs->ti->error = "sync/nosync and rebuild are mutually exclusive";
1480 		return -EINVAL;
1481 	}
1482 
1483 	if (write_mostly >= rs->md.raid_disks) {
1484 		rs->ti->error = "Can't set all raid1 devices to write_mostly";
1485 		return -EINVAL;
1486 	}
1487 
1488 	if (rs->md.sync_speed_max &&
1489 	    rs->md.sync_speed_min > rs->md.sync_speed_max) {
1490 		rs->ti->error = "Bogus recovery rates";
1491 		return -EINVAL;
1492 	}
1493 
1494 	if (validate_region_size(rs, region_size))
1495 		return -EINVAL;
1496 
1497 	if (rs->md.chunk_sectors)
1498 		max_io_len = rs->md.chunk_sectors;
1499 	else
1500 		max_io_len = region_size;
1501 
1502 	if (dm_set_target_max_io_len(rs->ti, max_io_len))
1503 		return -EINVAL;
1504 
1505 	if (rt_is_raid10(rt)) {
1506 		if (raid10_copies > rs->md.raid_disks) {
1507 			rs->ti->error = "Not enough devices to satisfy specification";
1508 			return -EINVAL;
1509 		}
1510 
1511 		rs->md.new_layout = raid10_format_to_md_layout(rs, raid10_format, raid10_copies);
1512 		if (rs->md.new_layout < 0) {
1513 			rs->ti->error = "Error getting raid10 format";
1514 			return rs->md.new_layout;
1515 		}
1516 
1517 		rt = get_raid_type_by_ll(10, rs->md.new_layout);
1518 		if (!rt) {
1519 			rs->ti->error = "Failed to recognize new raid10 layout";
1520 			return -EINVAL;
1521 		}
1522 
1523 		if ((rt->algorithm == ALGORITHM_RAID10_DEFAULT ||
1524 		     rt->algorithm == ALGORITHM_RAID10_NEAR) &&
1525 		    test_bit(__CTR_FLAG_RAID10_USE_NEAR_SETS, &rs->ctr_flags)) {
1526 			rs->ti->error = "RAID10 format 'near' and 'raid10_use_near_sets' are incompatible";
1527 			return -EINVAL;
1528 		}
1529 	}
1530 
1531 	rs->raid10_copies = raid10_copies;
1532 
1533 	/* Assume there are no metadata devices until the drives are parsed */
1534 	rs->md.persistent = 0;
1535 	rs->md.external = 1;
1536 
1537 	/* Check, if any invalid ctr arguments have been passed in for the raid level */
1538 	return rs_check_for_valid_flags(rs);
1539 }
1540 
1541 /* Set raid4/5/6 cache size */
1542 static int rs_set_raid456_stripe_cache(struct raid_set *rs)
1543 {
1544 	int r;
1545 	struct r5conf *conf;
1546 	struct mddev *mddev = &rs->md;
1547 	uint32_t min_stripes = max(mddev->chunk_sectors, mddev->new_chunk_sectors) / 2;
1548 	uint32_t nr_stripes = rs->stripe_cache_entries;
1549 
1550 	if (!rt_is_raid456(rs->raid_type)) {
1551 		rs->ti->error = "Inappropriate raid level; cannot change stripe_cache size";
1552 		return -EINVAL;
1553 	}
1554 
1555 	if (nr_stripes < min_stripes) {
1556 		DMINFO("Adjusting requested %u stripe cache entries to %u to suit stripe size",
1557 		       nr_stripes, min_stripes);
1558 		nr_stripes = min_stripes;
1559 	}
1560 
1561 	conf = mddev->private;
1562 	if (!conf) {
1563 		rs->ti->error = "Cannot change stripe_cache size on inactive RAID set";
1564 		return -EINVAL;
1565 	}
1566 
1567 	/* Try setting number of stripes in raid456 stripe cache */
1568 	if (conf->min_nr_stripes != nr_stripes) {
1569 		r = raid5_set_cache_size(mddev, nr_stripes);
1570 		if (r) {
1571 			rs->ti->error = "Failed to set raid4/5/6 stripe cache size";
1572 			return r;
1573 		}
1574 
1575 		DMINFO("%u stripe cache entries", nr_stripes);
1576 	}
1577 
1578 	return 0;
1579 }
1580 
1581 /* Return # of data stripes as kept in mddev as of @rs (i.e. as of superblock) */
1582 static unsigned int mddev_data_stripes(struct raid_set *rs)
1583 {
1584 	return rs->md.raid_disks - rs->raid_type->parity_devs;
1585 }
1586 
1587 /* Return # of data stripes of @rs (i.e. as of ctr) */
1588 static unsigned int rs_data_stripes(struct raid_set *rs)
1589 {
1590 	return rs->raid_disks - rs->raid_type->parity_devs;
1591 }
1592 
1593 /*
1594  * Retrieve rdev->sectors from any valid raid device of @rs
1595  * to allow userpace to pass in arbitray "- -" device tupples.
1596  */
1597 static sector_t __rdev_sectors(struct raid_set *rs)
1598 {
1599 	int i;
1600 
1601 	for (i = 0; i < rs->raid_disks; i++) {
1602 		struct md_rdev *rdev = &rs->dev[i].rdev;
1603 
1604 		if (!test_bit(Journal, &rdev->flags) &&
1605 		    rdev->bdev && rdev->sectors)
1606 			return rdev->sectors;
1607 	}
1608 
1609 	return 0;
1610 }
1611 
1612 /* Check that calculated dev_sectors fits all component devices. */
1613 static int _check_data_dev_sectors(struct raid_set *rs)
1614 {
1615 	sector_t ds = ~0;
1616 	struct md_rdev *rdev;
1617 
1618 	rdev_for_each(rdev, &rs->md)
1619 		if (!test_bit(Journal, &rdev->flags) && rdev->bdev) {
1620 			ds = min(ds, bdev_nr_sectors(rdev->bdev));
1621 			if (ds < rs->md.dev_sectors) {
1622 				rs->ti->error = "Component device(s) too small";
1623 				return -EINVAL;
1624 			}
1625 		}
1626 
1627 	return 0;
1628 }
1629 
1630 /* Get reshape sectors from data_offsets or raid set */
1631 static sector_t _get_reshape_sectors(struct raid_set *rs)
1632 {
1633 	struct md_rdev *rdev;
1634 	sector_t reshape_sectors = 0;
1635 
1636 	rdev_for_each(rdev, &rs->md)
1637 		if (!test_bit(Journal, &rdev->flags)) {
1638 			reshape_sectors = (rdev->data_offset > rdev->new_data_offset) ?
1639 					rdev->data_offset - rdev->new_data_offset :
1640 					rdev->new_data_offset - rdev->data_offset;
1641 			break;
1642 		}
1643 
1644 	return max(reshape_sectors, (sector_t) rs->data_offset);
1645 }
1646 
1647 /* Calculate the sectors per device and per array used for @rs */
1648 static int rs_set_dev_and_array_sectors(struct raid_set *rs, sector_t sectors, bool use_mddev)
1649 {
1650 	int delta_disks;
1651 	unsigned int data_stripes;
1652 	sector_t array_sectors = sectors, dev_sectors = sectors;
1653 	struct mddev *mddev = &rs->md;
1654 
1655 	if (use_mddev) {
1656 		delta_disks = mddev->delta_disks;
1657 		data_stripes = mddev_data_stripes(rs);
1658 	} else {
1659 		delta_disks = rs->delta_disks;
1660 		data_stripes = rs_data_stripes(rs);
1661 	}
1662 
1663 	/* Special raid1 case w/o delta_disks support (yet) */
1664 	if (rt_is_raid1(rs->raid_type))
1665 		;
1666 	else if (rt_is_raid10(rs->raid_type)) {
1667 		if (rs->raid10_copies < 2 ||
1668 		    delta_disks < 0) {
1669 			rs->ti->error = "Bogus raid10 data copies or delta disks";
1670 			return -EINVAL;
1671 		}
1672 
1673 		dev_sectors *= rs->raid10_copies;
1674 		if (sector_div(dev_sectors, data_stripes))
1675 			goto bad;
1676 
1677 		array_sectors = (data_stripes + delta_disks) * (dev_sectors - _get_reshape_sectors(rs));
1678 		if (sector_div(array_sectors, rs->raid10_copies))
1679 			goto bad;
1680 
1681 	} else if (sector_div(dev_sectors, data_stripes))
1682 		goto bad;
1683 
1684 	else
1685 		/* Striped layouts */
1686 		array_sectors = (data_stripes + delta_disks) * (dev_sectors - _get_reshape_sectors(rs));
1687 
1688 	mddev->array_sectors = array_sectors;
1689 	mddev->dev_sectors = dev_sectors;
1690 	rs_set_rdev_sectors(rs);
1691 
1692 	return _check_data_dev_sectors(rs);
1693 bad:
1694 	rs->ti->error = "Target length not divisible by number of data devices";
1695 	return -EINVAL;
1696 }
1697 
1698 /* Setup recovery on @rs */
1699 static void rs_setup_recovery(struct raid_set *rs, sector_t dev_sectors)
1700 {
1701 	/* raid0 does not recover */
1702 	if (rs_is_raid0(rs))
1703 		rs->md.recovery_cp = MaxSector;
1704 	/*
1705 	 * A raid6 set has to be recovered either
1706 	 * completely or for the grown part to
1707 	 * ensure proper parity and Q-Syndrome
1708 	 */
1709 	else if (rs_is_raid6(rs))
1710 		rs->md.recovery_cp = dev_sectors;
1711 	/*
1712 	 * Other raid set types may skip recovery
1713 	 * depending on the 'nosync' flag.
1714 	 */
1715 	else
1716 		rs->md.recovery_cp = test_bit(__CTR_FLAG_NOSYNC, &rs->ctr_flags)
1717 				     ? MaxSector : dev_sectors;
1718 }
1719 
1720 static void do_table_event(struct work_struct *ws)
1721 {
1722 	struct raid_set *rs = container_of(ws, struct raid_set, md.event_work);
1723 
1724 	smp_rmb(); /* Make sure we access most actual mddev properties */
1725 
1726 	/* Only grow size resulting from added stripe(s) after reshape ended. */
1727 	if (!rs_is_reshaping(rs) &&
1728 	    rs->array_sectors > rs->md.array_sectors &&
1729 	    !rs->md.delta_disks &&
1730 	    rs->md.raid_disks == rs->raid_disks) {
1731 		/* The raid10 personality doesn't provide proper device sizes -> correct. */
1732 		if (rs_is_raid10(rs))
1733 			rs_set_rdev_sectors(rs);
1734 
1735 		rs->md.array_sectors = rs->array_sectors;
1736 		rs_set_capacity(rs);
1737 	}
1738 
1739 	dm_table_event(rs->ti->table);
1740 }
1741 
1742 /*
1743  * Make sure a valid takover (level switch) is being requested on @rs
1744  *
1745  * Conversions of raid sets from one MD personality to another
1746  * have to conform to restrictions which are enforced here.
1747  */
1748 static int rs_check_takeover(struct raid_set *rs)
1749 {
1750 	struct mddev *mddev = &rs->md;
1751 	unsigned int near_copies;
1752 
1753 	if (rs->md.degraded) {
1754 		rs->ti->error = "Can't takeover degraded raid set";
1755 		return -EPERM;
1756 	}
1757 
1758 	if (rs_is_reshaping(rs)) {
1759 		rs->ti->error = "Can't takeover reshaping raid set";
1760 		return -EPERM;
1761 	}
1762 
1763 	switch (mddev->level) {
1764 	case 0:
1765 		/* raid0 -> raid1/5 with one disk */
1766 		if ((mddev->new_level == 1 || mddev->new_level == 5) &&
1767 		    mddev->raid_disks == 1)
1768 			return 0;
1769 
1770 		/* raid0 -> raid10 */
1771 		if (mddev->new_level == 10 &&
1772 		    !(rs->raid_disks % mddev->raid_disks))
1773 			return 0;
1774 
1775 		/* raid0 with multiple disks -> raid4/5/6 */
1776 		if (__within_range(mddev->new_level, 4, 6) &&
1777 		    mddev->new_layout == ALGORITHM_PARITY_N &&
1778 		    mddev->raid_disks > 1)
1779 			return 0;
1780 
1781 		break;
1782 
1783 	case 10:
1784 		/* Can't takeover raid10_offset! */
1785 		if (__is_raid10_offset(mddev->layout))
1786 			break;
1787 
1788 		near_copies = __raid10_near_copies(mddev->layout);
1789 
1790 		/* raid10* -> raid0 */
1791 		if (mddev->new_level == 0) {
1792 			/* Can takeover raid10_near with raid disks divisable by data copies! */
1793 			if (near_copies > 1 &&
1794 			    !(mddev->raid_disks % near_copies)) {
1795 				mddev->raid_disks /= near_copies;
1796 				mddev->delta_disks = mddev->raid_disks;
1797 				return 0;
1798 			}
1799 
1800 			/* Can takeover raid10_far */
1801 			if (near_copies == 1 &&
1802 			    __raid10_far_copies(mddev->layout) > 1)
1803 				return 0;
1804 
1805 			break;
1806 		}
1807 
1808 		/* raid10_{near,far} -> raid1 */
1809 		if (mddev->new_level == 1 &&
1810 		    max(near_copies, __raid10_far_copies(mddev->layout)) == mddev->raid_disks)
1811 			return 0;
1812 
1813 		/* raid10_{near,far} with 2 disks -> raid4/5 */
1814 		if (__within_range(mddev->new_level, 4, 5) &&
1815 		    mddev->raid_disks == 2)
1816 			return 0;
1817 		break;
1818 
1819 	case 1:
1820 		/* raid1 with 2 disks -> raid4/5 */
1821 		if (__within_range(mddev->new_level, 4, 5) &&
1822 		    mddev->raid_disks == 2) {
1823 			mddev->degraded = 1;
1824 			return 0;
1825 		}
1826 
1827 		/* raid1 -> raid0 */
1828 		if (mddev->new_level == 0 &&
1829 		    mddev->raid_disks == 1)
1830 			return 0;
1831 
1832 		/* raid1 -> raid10 */
1833 		if (mddev->new_level == 10)
1834 			return 0;
1835 		break;
1836 
1837 	case 4:
1838 		/* raid4 -> raid0 */
1839 		if (mddev->new_level == 0)
1840 			return 0;
1841 
1842 		/* raid4 -> raid1/5 with 2 disks */
1843 		if ((mddev->new_level == 1 || mddev->new_level == 5) &&
1844 		    mddev->raid_disks == 2)
1845 			return 0;
1846 
1847 		/* raid4 -> raid5/6 with parity N */
1848 		if (__within_range(mddev->new_level, 5, 6) &&
1849 		    mddev->layout == ALGORITHM_PARITY_N)
1850 			return 0;
1851 		break;
1852 
1853 	case 5:
1854 		/* raid5 with parity N -> raid0 */
1855 		if (mddev->new_level == 0 &&
1856 		    mddev->layout == ALGORITHM_PARITY_N)
1857 			return 0;
1858 
1859 		/* raid5 with parity N -> raid4 */
1860 		if (mddev->new_level == 4 &&
1861 		    mddev->layout == ALGORITHM_PARITY_N)
1862 			return 0;
1863 
1864 		/* raid5 with 2 disks -> raid1/4/10 */
1865 		if ((mddev->new_level == 1 || mddev->new_level == 4 || mddev->new_level == 10) &&
1866 		    mddev->raid_disks == 2)
1867 			return 0;
1868 
1869 		/* raid5_* ->  raid6_*_6 with Q-Syndrome N (e.g. raid5_ra -> raid6_ra_6 */
1870 		if (mddev->new_level == 6 &&
1871 		    ((mddev->layout == ALGORITHM_PARITY_N && mddev->new_layout == ALGORITHM_PARITY_N) ||
1872 		      __within_range(mddev->new_layout, ALGORITHM_LEFT_ASYMMETRIC_6, ALGORITHM_RIGHT_SYMMETRIC_6)))
1873 			return 0;
1874 		break;
1875 
1876 	case 6:
1877 		/* raid6 with parity N -> raid0 */
1878 		if (mddev->new_level == 0 &&
1879 		    mddev->layout == ALGORITHM_PARITY_N)
1880 			return 0;
1881 
1882 		/* raid6 with parity N -> raid4 */
1883 		if (mddev->new_level == 4 &&
1884 		    mddev->layout == ALGORITHM_PARITY_N)
1885 			return 0;
1886 
1887 		/* raid6_*_n with Q-Syndrome N -> raid5_* */
1888 		if (mddev->new_level == 5 &&
1889 		    ((mddev->layout == ALGORITHM_PARITY_N && mddev->new_layout == ALGORITHM_PARITY_N) ||
1890 		     __within_range(mddev->new_layout, ALGORITHM_LEFT_ASYMMETRIC, ALGORITHM_RIGHT_SYMMETRIC)))
1891 			return 0;
1892 		break;
1893 
1894 	default:
1895 		break;
1896 	}
1897 
1898 	rs->ti->error = "takeover not possible";
1899 	return -EINVAL;
1900 }
1901 
1902 /* True if @rs requested to be taken over */
1903 static bool rs_takeover_requested(struct raid_set *rs)
1904 {
1905 	return rs->md.new_level != rs->md.level;
1906 }
1907 
1908 /* True if layout is set to reshape. */
1909 static bool rs_is_layout_change(struct raid_set *rs, bool use_mddev)
1910 {
1911 	return (use_mddev ? rs->md.delta_disks : rs->delta_disks) ||
1912 	       rs->md.new_layout != rs->md.layout ||
1913 	       rs->md.new_chunk_sectors != rs->md.chunk_sectors;
1914 }
1915 
1916 /* True if @rs is requested to reshape by ctr */
1917 static bool rs_reshape_requested(struct raid_set *rs)
1918 {
1919 	bool change;
1920 	struct mddev *mddev = &rs->md;
1921 
1922 	if (rs_takeover_requested(rs))
1923 		return false;
1924 
1925 	if (rs_is_raid0(rs))
1926 		return false;
1927 
1928 	change = rs_is_layout_change(rs, false);
1929 
1930 	/* Historical case to support raid1 reshape without delta disks */
1931 	if (rs_is_raid1(rs)) {
1932 		if (rs->delta_disks)
1933 			return !!rs->delta_disks;
1934 
1935 		return !change &&
1936 		       mddev->raid_disks != rs->raid_disks;
1937 	}
1938 
1939 	if (rs_is_raid10(rs))
1940 		return change &&
1941 		       !__is_raid10_far(mddev->new_layout) &&
1942 		       rs->delta_disks >= 0;
1943 
1944 	return change;
1945 }
1946 
1947 /*  Features */
1948 #define	FEATURE_FLAG_SUPPORTS_V190	0x1 /* Supports extended superblock */
1949 
1950 /* State flags for sb->flags */
1951 #define	SB_FLAG_RESHAPE_ACTIVE		0x1
1952 #define	SB_FLAG_RESHAPE_BACKWARDS	0x2
1953 
1954 /*
1955  * This structure is never routinely used by userspace, unlike md superblocks.
1956  * Devices with this superblock should only ever be accessed via device-mapper.
1957  */
1958 #define DM_RAID_MAGIC 0x64526D44
1959 struct dm_raid_superblock {
1960 	__le32 magic;		/* "DmRd" */
1961 	__le32 compat_features;	/* Used to indicate compatible features (like 1.9.0 ondisk metadata extension) */
1962 
1963 	__le32 num_devices;	/* Number of devices in this raid set. (Max 64) */
1964 	__le32 array_position;	/* The position of this drive in the raid set */
1965 
1966 	__le64 events;		/* Incremented by md when superblock updated */
1967 	__le64 failed_devices;	/* Pre 1.9.0 part of bit field of devices to */
1968 				/* indicate failures (see extension below) */
1969 
1970 	/*
1971 	 * This offset tracks the progress of the repair or replacement of
1972 	 * an individual drive.
1973 	 */
1974 	__le64 disk_recovery_offset;
1975 
1976 	/*
1977 	 * This offset tracks the progress of the initial raid set
1978 	 * synchronisation/parity calculation.
1979 	 */
1980 	__le64 array_resync_offset;
1981 
1982 	/*
1983 	 * raid characteristics
1984 	 */
1985 	__le32 level;
1986 	__le32 layout;
1987 	__le32 stripe_sectors;
1988 
1989 	/********************************************************************
1990 	 * BELOW FOLLOW V1.9.0 EXTENSIONS TO THE PRISTINE SUPERBLOCK FORMAT!!!
1991 	 *
1992 	 * FEATURE_FLAG_SUPPORTS_V190 in the compat_features member indicates that those exist
1993 	 */
1994 
1995 	__le32 flags; /* Flags defining array states for reshaping */
1996 
1997 	/*
1998 	 * This offset tracks the progress of a raid
1999 	 * set reshape in order to be able to restart it
2000 	 */
2001 	__le64 reshape_position;
2002 
2003 	/*
2004 	 * These define the properties of the array in case of an interrupted reshape
2005 	 */
2006 	__le32 new_level;
2007 	__le32 new_layout;
2008 	__le32 new_stripe_sectors;
2009 	__le32 delta_disks;
2010 
2011 	__le64 array_sectors; /* Array size in sectors */
2012 
2013 	/*
2014 	 * Sector offsets to data on devices (reshaping).
2015 	 * Needed to support out of place reshaping, thus
2016 	 * not writing over any stripes whilst converting
2017 	 * them from old to new layout
2018 	 */
2019 	__le64 data_offset;
2020 	__le64 new_data_offset;
2021 
2022 	__le64 sectors; /* Used device size in sectors */
2023 
2024 	/*
2025 	 * Additional Bit field of devices indicating failures to support
2026 	 * up to 256 devices with the 1.9.0 on-disk metadata format
2027 	 */
2028 	__le64 extended_failed_devices[DISKS_ARRAY_ELEMS - 1];
2029 
2030 	__le32 incompat_features;	/* Used to indicate any incompatible features */
2031 
2032 	/* Always set rest up to logical block size to 0 when writing (see get_metadata_device() below). */
2033 } __packed;
2034 
2035 /*
2036  * Check for reshape constraints on raid set @rs:
2037  *
2038  * - reshape function non-existent
2039  * - degraded set
2040  * - ongoing recovery
2041  * - ongoing reshape
2042  *
2043  * Returns 0 if none or -EPERM if given constraint
2044  * and error message reference in @errmsg
2045  */
2046 static int rs_check_reshape(struct raid_set *rs)
2047 {
2048 	struct mddev *mddev = &rs->md;
2049 
2050 	if (!mddev->pers || !mddev->pers->check_reshape)
2051 		rs->ti->error = "Reshape not supported";
2052 	else if (mddev->degraded)
2053 		rs->ti->error = "Can't reshape degraded raid set";
2054 	else if (rs_is_recovering(rs))
2055 		rs->ti->error = "Convert request on recovering raid set prohibited";
2056 	else if (rs_is_reshaping(rs))
2057 		rs->ti->error = "raid set already reshaping!";
2058 	else if (!(rs_is_raid1(rs) || rs_is_raid10(rs) || rs_is_raid456(rs)))
2059 		rs->ti->error = "Reshaping only supported for raid1/4/5/6/10";
2060 	else
2061 		return 0;
2062 
2063 	return -EPERM;
2064 }
2065 
2066 static int read_disk_sb(struct md_rdev *rdev, int size, bool force_reload)
2067 {
2068 	BUG_ON(!rdev->sb_page);
2069 
2070 	if (rdev->sb_loaded && !force_reload)
2071 		return 0;
2072 
2073 	rdev->sb_loaded = 0;
2074 
2075 	if (!sync_page_io(rdev, 0, size, rdev->sb_page, REQ_OP_READ, true)) {
2076 		DMERR("Failed to read superblock of device at position %d",
2077 		      rdev->raid_disk);
2078 		md_error(rdev->mddev, rdev);
2079 		set_bit(Faulty, &rdev->flags);
2080 		return -EIO;
2081 	}
2082 
2083 	rdev->sb_loaded = 1;
2084 
2085 	return 0;
2086 }
2087 
2088 static void sb_retrieve_failed_devices(struct dm_raid_superblock *sb, uint64_t *failed_devices)
2089 {
2090 	failed_devices[0] = le64_to_cpu(sb->failed_devices);
2091 	memset(failed_devices + 1, 0, sizeof(sb->extended_failed_devices));
2092 
2093 	if (le32_to_cpu(sb->compat_features) & FEATURE_FLAG_SUPPORTS_V190) {
2094 		int i = ARRAY_SIZE(sb->extended_failed_devices);
2095 
2096 		while (i--)
2097 			failed_devices[i+1] = le64_to_cpu(sb->extended_failed_devices[i]);
2098 	}
2099 }
2100 
2101 static void sb_update_failed_devices(struct dm_raid_superblock *sb, uint64_t *failed_devices)
2102 {
2103 	int i = ARRAY_SIZE(sb->extended_failed_devices);
2104 
2105 	sb->failed_devices = cpu_to_le64(failed_devices[0]);
2106 	while (i--)
2107 		sb->extended_failed_devices[i] = cpu_to_le64(failed_devices[i+1]);
2108 }
2109 
2110 /*
2111  * Synchronize the superblock members with the raid set properties
2112  *
2113  * All superblock data is little endian.
2114  */
2115 static void super_sync(struct mddev *mddev, struct md_rdev *rdev)
2116 {
2117 	bool update_failed_devices = false;
2118 	unsigned int i;
2119 	uint64_t failed_devices[DISKS_ARRAY_ELEMS];
2120 	struct dm_raid_superblock *sb;
2121 	struct raid_set *rs = container_of(mddev, struct raid_set, md);
2122 
2123 	/* No metadata device, no superblock */
2124 	if (!rdev->meta_bdev)
2125 		return;
2126 
2127 	BUG_ON(!rdev->sb_page);
2128 
2129 	sb = page_address(rdev->sb_page);
2130 
2131 	sb_retrieve_failed_devices(sb, failed_devices);
2132 
2133 	for (i = 0; i < rs->raid_disks; i++)
2134 		if (!rs->dev[i].data_dev || test_bit(Faulty, &rs->dev[i].rdev.flags)) {
2135 			update_failed_devices = true;
2136 			set_bit(i, (void *) failed_devices);
2137 		}
2138 
2139 	if (update_failed_devices)
2140 		sb_update_failed_devices(sb, failed_devices);
2141 
2142 	sb->magic = cpu_to_le32(DM_RAID_MAGIC);
2143 	sb->compat_features = cpu_to_le32(FEATURE_FLAG_SUPPORTS_V190);
2144 
2145 	sb->num_devices = cpu_to_le32(mddev->raid_disks);
2146 	sb->array_position = cpu_to_le32(rdev->raid_disk);
2147 
2148 	sb->events = cpu_to_le64(mddev->events);
2149 
2150 	sb->disk_recovery_offset = cpu_to_le64(rdev->recovery_offset);
2151 	sb->array_resync_offset = cpu_to_le64(mddev->recovery_cp);
2152 
2153 	sb->level = cpu_to_le32(mddev->level);
2154 	sb->layout = cpu_to_le32(mddev->layout);
2155 	sb->stripe_sectors = cpu_to_le32(mddev->chunk_sectors);
2156 
2157 	/********************************************************************
2158 	 * BELOW FOLLOW V1.9.0 EXTENSIONS TO THE PRISTINE SUPERBLOCK FORMAT!!!
2159 	 *
2160 	 * FEATURE_FLAG_SUPPORTS_V190 in the compat_features member indicates that those exist
2161 	 */
2162 	sb->new_level = cpu_to_le32(mddev->new_level);
2163 	sb->new_layout = cpu_to_le32(mddev->new_layout);
2164 	sb->new_stripe_sectors = cpu_to_le32(mddev->new_chunk_sectors);
2165 
2166 	sb->delta_disks = cpu_to_le32(mddev->delta_disks);
2167 
2168 	smp_rmb(); /* Make sure we access most recent reshape position */
2169 	sb->reshape_position = cpu_to_le64(mddev->reshape_position);
2170 	if (le64_to_cpu(sb->reshape_position) != MaxSector) {
2171 		/* Flag ongoing reshape */
2172 		sb->flags |= cpu_to_le32(SB_FLAG_RESHAPE_ACTIVE);
2173 
2174 		if (mddev->delta_disks < 0 || mddev->reshape_backwards)
2175 			sb->flags |= cpu_to_le32(SB_FLAG_RESHAPE_BACKWARDS);
2176 	} else {
2177 		/* Clear reshape flags */
2178 		sb->flags &= ~(cpu_to_le32(SB_FLAG_RESHAPE_ACTIVE|SB_FLAG_RESHAPE_BACKWARDS));
2179 	}
2180 
2181 	sb->array_sectors = cpu_to_le64(mddev->array_sectors);
2182 	sb->data_offset = cpu_to_le64(rdev->data_offset);
2183 	sb->new_data_offset = cpu_to_le64(rdev->new_data_offset);
2184 	sb->sectors = cpu_to_le64(rdev->sectors);
2185 	sb->incompat_features = cpu_to_le32(0);
2186 
2187 	/* Zero out the rest of the payload after the size of the superblock */
2188 	memset(sb + 1, 0, rdev->sb_size - sizeof(*sb));
2189 }
2190 
2191 /*
2192  * super_load
2193  *
2194  * This function creates a superblock if one is not found on the device
2195  * and will decide which superblock to use if there's a choice.
2196  *
2197  * Return: 1 if use rdev, 0 if use refdev, -Exxx otherwise
2198  */
2199 static int super_load(struct md_rdev *rdev, struct md_rdev *refdev)
2200 {
2201 	int r;
2202 	struct dm_raid_superblock *sb;
2203 	struct dm_raid_superblock *refsb;
2204 	uint64_t events_sb, events_refsb;
2205 
2206 	r = read_disk_sb(rdev, rdev->sb_size, false);
2207 	if (r)
2208 		return r;
2209 
2210 	sb = page_address(rdev->sb_page);
2211 
2212 	/*
2213 	 * Two cases that we want to write new superblocks and rebuild:
2214 	 * 1) New device (no matching magic number)
2215 	 * 2) Device specified for rebuild (!In_sync w/ offset == 0)
2216 	 */
2217 	if ((sb->magic != cpu_to_le32(DM_RAID_MAGIC)) ||
2218 	    (!test_bit(In_sync, &rdev->flags) && !rdev->recovery_offset)) {
2219 		super_sync(rdev->mddev, rdev);
2220 
2221 		set_bit(FirstUse, &rdev->flags);
2222 		sb->compat_features = cpu_to_le32(FEATURE_FLAG_SUPPORTS_V190);
2223 
2224 		/* Force writing of superblocks to disk */
2225 		set_bit(MD_SB_CHANGE_DEVS, &rdev->mddev->sb_flags);
2226 
2227 		/* Any superblock is better than none, choose that if given */
2228 		return refdev ? 0 : 1;
2229 	}
2230 
2231 	if (!refdev)
2232 		return 1;
2233 
2234 	events_sb = le64_to_cpu(sb->events);
2235 
2236 	refsb = page_address(refdev->sb_page);
2237 	events_refsb = le64_to_cpu(refsb->events);
2238 
2239 	return (events_sb > events_refsb) ? 1 : 0;
2240 }
2241 
2242 static int super_init_validation(struct raid_set *rs, struct md_rdev *rdev)
2243 {
2244 	int role;
2245 	struct mddev *mddev = &rs->md;
2246 	uint64_t events_sb;
2247 	uint64_t failed_devices[DISKS_ARRAY_ELEMS];
2248 	struct dm_raid_superblock *sb;
2249 	uint32_t new_devs = 0, rebuild_and_new = 0, rebuilds = 0;
2250 	struct md_rdev *r;
2251 	struct dm_raid_superblock *sb2;
2252 
2253 	sb = page_address(rdev->sb_page);
2254 	events_sb = le64_to_cpu(sb->events);
2255 
2256 	/*
2257 	 * Initialise to 1 if this is a new superblock.
2258 	 */
2259 	mddev->events = events_sb ? : 1;
2260 
2261 	mddev->reshape_position = MaxSector;
2262 
2263 	mddev->raid_disks = le32_to_cpu(sb->num_devices);
2264 	mddev->level = le32_to_cpu(sb->level);
2265 	mddev->layout = le32_to_cpu(sb->layout);
2266 	mddev->chunk_sectors = le32_to_cpu(sb->stripe_sectors);
2267 
2268 	/*
2269 	 * Reshaping is supported, e.g. reshape_position is valid
2270 	 * in superblock and superblock content is authoritative.
2271 	 */
2272 	if (le32_to_cpu(sb->compat_features) & FEATURE_FLAG_SUPPORTS_V190) {
2273 		/* Superblock is authoritative wrt given raid set layout! */
2274 		mddev->new_level = le32_to_cpu(sb->new_level);
2275 		mddev->new_layout = le32_to_cpu(sb->new_layout);
2276 		mddev->new_chunk_sectors = le32_to_cpu(sb->new_stripe_sectors);
2277 		mddev->delta_disks = le32_to_cpu(sb->delta_disks);
2278 		mddev->array_sectors = le64_to_cpu(sb->array_sectors);
2279 
2280 		/* raid was reshaping and got interrupted */
2281 		if (le32_to_cpu(sb->flags) & SB_FLAG_RESHAPE_ACTIVE) {
2282 			if (test_bit(__CTR_FLAG_DELTA_DISKS, &rs->ctr_flags)) {
2283 				DMERR("Reshape requested but raid set is still reshaping");
2284 				return -EINVAL;
2285 			}
2286 
2287 			if (mddev->delta_disks < 0 ||
2288 			    (!mddev->delta_disks && (le32_to_cpu(sb->flags) & SB_FLAG_RESHAPE_BACKWARDS)))
2289 				mddev->reshape_backwards = 1;
2290 			else
2291 				mddev->reshape_backwards = 0;
2292 
2293 			mddev->reshape_position = le64_to_cpu(sb->reshape_position);
2294 			rs->raid_type = get_raid_type_by_ll(mddev->level, mddev->layout);
2295 		}
2296 
2297 	} else {
2298 		/*
2299 		 * No takeover/reshaping, because we don't have the extended v1.9.0 metadata
2300 		 */
2301 		struct raid_type *rt_cur = get_raid_type_by_ll(mddev->level, mddev->layout);
2302 		struct raid_type *rt_new = get_raid_type_by_ll(mddev->new_level, mddev->new_layout);
2303 
2304 		if (rs_takeover_requested(rs)) {
2305 			if (rt_cur && rt_new)
2306 				DMERR("Takeover raid sets from %s to %s not yet supported by metadata. (raid level change)",
2307 				      rt_cur->name, rt_new->name);
2308 			else
2309 				DMERR("Takeover raid sets not yet supported by metadata. (raid level change)");
2310 			return -EINVAL;
2311 		} else if (rs_reshape_requested(rs)) {
2312 			DMERR("Reshaping raid sets not yet supported by metadata. (raid layout change keeping level)");
2313 			if (mddev->layout != mddev->new_layout) {
2314 				if (rt_cur && rt_new)
2315 					DMERR("	 current layout %s vs new layout %s",
2316 					      rt_cur->name, rt_new->name);
2317 				else
2318 					DMERR("	 current layout 0x%X vs new layout 0x%X",
2319 					      le32_to_cpu(sb->layout), mddev->new_layout);
2320 			}
2321 			if (mddev->chunk_sectors != mddev->new_chunk_sectors)
2322 				DMERR("	 current stripe sectors %u vs new stripe sectors %u",
2323 				      mddev->chunk_sectors, mddev->new_chunk_sectors);
2324 			if (rs->delta_disks)
2325 				DMERR("	 current %u disks vs new %u disks",
2326 				      mddev->raid_disks, mddev->raid_disks + rs->delta_disks);
2327 			if (rs_is_raid10(rs)) {
2328 				DMERR("	 Old layout: %s w/ %u copies",
2329 				      raid10_md_layout_to_format(mddev->layout),
2330 				      raid10_md_layout_to_copies(mddev->layout));
2331 				DMERR("	 New layout: %s w/ %u copies",
2332 				      raid10_md_layout_to_format(mddev->new_layout),
2333 				      raid10_md_layout_to_copies(mddev->new_layout));
2334 			}
2335 			return -EINVAL;
2336 		}
2337 
2338 		DMINFO("Discovered old metadata format; upgrading to extended metadata format");
2339 	}
2340 
2341 	if (!test_bit(__CTR_FLAG_NOSYNC, &rs->ctr_flags))
2342 		mddev->recovery_cp = le64_to_cpu(sb->array_resync_offset);
2343 
2344 	/*
2345 	 * During load, we set FirstUse if a new superblock was written.
2346 	 * There are two reasons we might not have a superblock:
2347 	 * 1) The raid set is brand new - in which case, all of the
2348 	 *    devices must have their In_sync bit set.	Also,
2349 	 *    recovery_cp must be 0, unless forced.
2350 	 * 2) This is a new device being added to an old raid set
2351 	 *    and the new device needs to be rebuilt - in which
2352 	 *    case the In_sync bit will /not/ be set and
2353 	 *    recovery_cp must be MaxSector.
2354 	 * 3) This is/are a new device(s) being added to an old
2355 	 *    raid set during takeover to a higher raid level
2356 	 *    to provide capacity for redundancy or during reshape
2357 	 *    to add capacity to grow the raid set.
2358 	 */
2359 	rdev_for_each(r, mddev) {
2360 		if (test_bit(Journal, &rdev->flags))
2361 			continue;
2362 
2363 		if (test_bit(FirstUse, &r->flags))
2364 			new_devs++;
2365 
2366 		if (!test_bit(In_sync, &r->flags)) {
2367 			DMINFO("Device %d specified for rebuild; clearing superblock",
2368 				r->raid_disk);
2369 			rebuilds++;
2370 
2371 			if (test_bit(FirstUse, &r->flags))
2372 				rebuild_and_new++;
2373 		}
2374 	}
2375 
2376 	if (new_devs == rs->raid_disks || !rebuilds) {
2377 		/* Replace a broken device */
2378 		if (new_devs == rs->raid_disks) {
2379 			DMINFO("Superblocks created for new raid set");
2380 			set_bit(MD_ARRAY_FIRST_USE, &mddev->flags);
2381 		} else if (new_devs != rebuilds &&
2382 			   new_devs != rs->delta_disks) {
2383 			DMERR("New device injected into existing raid set without "
2384 			      "'delta_disks' or 'rebuild' parameter specified");
2385 			return -EINVAL;
2386 		}
2387 	} else if (new_devs && new_devs != rebuilds) {
2388 		DMERR("%u 'rebuild' devices cannot be injected into"
2389 		      " a raid set with %u other first-time devices",
2390 		      rebuilds, new_devs);
2391 		return -EINVAL;
2392 	} else if (rebuilds) {
2393 		if (rebuild_and_new && rebuilds != rebuild_and_new) {
2394 			DMERR("new device%s provided without 'rebuild'",
2395 			      new_devs > 1 ? "s" : "");
2396 			return -EINVAL;
2397 		} else if (!test_bit(__CTR_FLAG_REBUILD, &rs->ctr_flags) && rs_is_recovering(rs)) {
2398 			DMERR("'rebuild' specified while raid set is not in-sync (recovery_cp=%llu)",
2399 			      (unsigned long long) mddev->recovery_cp);
2400 			return -EINVAL;
2401 		} else if (rs_is_reshaping(rs)) {
2402 			DMERR("'rebuild' specified while raid set is being reshaped (reshape_position=%llu)",
2403 			      (unsigned long long) mddev->reshape_position);
2404 			return -EINVAL;
2405 		}
2406 	}
2407 
2408 	/*
2409 	 * Now we set the Faulty bit for those devices that are
2410 	 * recorded in the superblock as failed.
2411 	 */
2412 	sb_retrieve_failed_devices(sb, failed_devices);
2413 	rdev_for_each(r, mddev) {
2414 		if (test_bit(Journal, &rdev->flags) ||
2415 		    !r->sb_page)
2416 			continue;
2417 		sb2 = page_address(r->sb_page);
2418 		sb2->failed_devices = 0;
2419 		memset(sb2->extended_failed_devices, 0, sizeof(sb2->extended_failed_devices));
2420 
2421 		/*
2422 		 * Check for any device re-ordering.
2423 		 */
2424 		if (!test_bit(FirstUse, &r->flags) && (r->raid_disk >= 0)) {
2425 			role = le32_to_cpu(sb2->array_position);
2426 			if (role < 0)
2427 				continue;
2428 
2429 			if (role != r->raid_disk) {
2430 				if (rs_is_raid10(rs) && __is_raid10_near(mddev->layout)) {
2431 					if (mddev->raid_disks % __raid10_near_copies(mddev->layout) ||
2432 					    rs->raid_disks % rs->raid10_copies) {
2433 						rs->ti->error =
2434 							"Cannot change raid10 near set to odd # of devices!";
2435 						return -EINVAL;
2436 					}
2437 
2438 					sb2->array_position = cpu_to_le32(r->raid_disk);
2439 
2440 				} else if (!(rs_is_raid10(rs) && rt_is_raid0(rs->raid_type)) &&
2441 					   !(rs_is_raid0(rs) && rt_is_raid10(rs->raid_type)) &&
2442 					   !rt_is_raid1(rs->raid_type)) {
2443 					rs->ti->error = "Cannot change device positions in raid set";
2444 					return -EINVAL;
2445 				}
2446 
2447 				DMINFO("raid device #%d now at position #%d", role, r->raid_disk);
2448 			}
2449 
2450 			/*
2451 			 * Partial recovery is performed on
2452 			 * returning failed devices.
2453 			 */
2454 			if (test_bit(role, (void *) failed_devices))
2455 				set_bit(Faulty, &r->flags);
2456 		}
2457 	}
2458 
2459 	return 0;
2460 }
2461 
2462 static int super_validate(struct raid_set *rs, struct md_rdev *rdev)
2463 {
2464 	struct mddev *mddev = &rs->md;
2465 	struct dm_raid_superblock *sb;
2466 
2467 	if (rs_is_raid0(rs) || !rdev->sb_page || rdev->raid_disk < 0)
2468 		return 0;
2469 
2470 	sb = page_address(rdev->sb_page);
2471 
2472 	/*
2473 	 * If mddev->events is not set, we know we have not yet initialized
2474 	 * the array.
2475 	 */
2476 	if (!mddev->events && super_init_validation(rs, rdev))
2477 		return -EINVAL;
2478 
2479 	if (le32_to_cpu(sb->compat_features) &&
2480 	    le32_to_cpu(sb->compat_features) != FEATURE_FLAG_SUPPORTS_V190) {
2481 		rs->ti->error = "Unable to assemble array: Unknown flag(s) in compatible feature flags";
2482 		return -EINVAL;
2483 	}
2484 
2485 	if (sb->incompat_features) {
2486 		rs->ti->error = "Unable to assemble array: No incompatible feature flags supported yet";
2487 		return -EINVAL;
2488 	}
2489 
2490 	/* Enable bitmap creation on @rs unless no metadevs or raid0 or journaled raid4/5/6 set. */
2491 	mddev->bitmap_info.offset = (rt_is_raid0(rs->raid_type) || rs->journal_dev.dev) ? 0 : to_sector(4096);
2492 	mddev->bitmap_info.default_offset = mddev->bitmap_info.offset;
2493 
2494 	if (!test_and_clear_bit(FirstUse, &rdev->flags)) {
2495 		/*
2496 		 * Retrieve rdev size stored in superblock to be prepared for shrink.
2497 		 * Check extended superblock members are present otherwise the size
2498 		 * will not be set!
2499 		 */
2500 		if (le32_to_cpu(sb->compat_features) & FEATURE_FLAG_SUPPORTS_V190)
2501 			rdev->sectors = le64_to_cpu(sb->sectors);
2502 
2503 		rdev->recovery_offset = le64_to_cpu(sb->disk_recovery_offset);
2504 		if (rdev->recovery_offset == MaxSector)
2505 			set_bit(In_sync, &rdev->flags);
2506 		/*
2507 		 * If no reshape in progress -> we're recovering single
2508 		 * disk(s) and have to set the device(s) to out-of-sync
2509 		 */
2510 		else if (!rs_is_reshaping(rs))
2511 			clear_bit(In_sync, &rdev->flags); /* Mandatory for recovery */
2512 	}
2513 
2514 	/*
2515 	 * If a device comes back, set it as not In_sync and no longer faulty.
2516 	 */
2517 	if (test_and_clear_bit(Faulty, &rdev->flags)) {
2518 		rdev->recovery_offset = 0;
2519 		clear_bit(In_sync, &rdev->flags);
2520 		rdev->saved_raid_disk = rdev->raid_disk;
2521 	}
2522 
2523 	/* Reshape support -> restore respective data offsets */
2524 	rdev->data_offset = le64_to_cpu(sb->data_offset);
2525 	rdev->new_data_offset = le64_to_cpu(sb->new_data_offset);
2526 
2527 	return 0;
2528 }
2529 
2530 /*
2531  * Analyse superblocks and select the freshest.
2532  */
2533 static int analyse_superblocks(struct dm_target *ti, struct raid_set *rs)
2534 {
2535 	int r;
2536 	struct md_rdev *rdev, *freshest;
2537 	struct mddev *mddev = &rs->md;
2538 
2539 	freshest = NULL;
2540 	rdev_for_each(rdev, mddev) {
2541 		if (test_bit(Journal, &rdev->flags))
2542 			continue;
2543 
2544 		if (!rdev->meta_bdev)
2545 			continue;
2546 
2547 		/* Set superblock offset/size for metadata device. */
2548 		rdev->sb_start = 0;
2549 		rdev->sb_size = bdev_logical_block_size(rdev->meta_bdev);
2550 		if (rdev->sb_size < sizeof(struct dm_raid_superblock) || rdev->sb_size > PAGE_SIZE) {
2551 			DMERR("superblock size of a logical block is no longer valid");
2552 			return -EINVAL;
2553 		}
2554 
2555 		/*
2556 		 * Skipping super_load due to CTR_FLAG_SYNC will cause
2557 		 * the array to undergo initialization again as
2558 		 * though it were new.	This is the intended effect
2559 		 * of the "sync" directive.
2560 		 *
2561 		 * With reshaping capability added, we must ensure that
2562 		 * the "sync" directive is disallowed during the reshape.
2563 		 */
2564 		if (test_bit(__CTR_FLAG_SYNC, &rs->ctr_flags))
2565 			continue;
2566 
2567 		r = super_load(rdev, freshest);
2568 
2569 		switch (r) {
2570 		case 1:
2571 			freshest = rdev;
2572 			break;
2573 		case 0:
2574 			break;
2575 		default:
2576 			/* This is a failure to read the superblock from the metadata device. */
2577 			/*
2578 			 * We have to keep any raid0 data/metadata device pairs or
2579 			 * the MD raid0 personality will fail to start the array.
2580 			 */
2581 			if (rs_is_raid0(rs))
2582 				continue;
2583 
2584 			/*
2585 			 * We keep the dm_devs to be able to emit the device tuple
2586 			 * properly on the table line in raid_status() (rather than
2587 			 * mistakenly acting as if '- -' got passed into the constructor).
2588 			 *
2589 			 * The rdev has to stay on the same_set list to allow for
2590 			 * the attempt to restore faulty devices on second resume.
2591 			 */
2592 			rdev->raid_disk = rdev->saved_raid_disk = -1;
2593 			break;
2594 		}
2595 	}
2596 
2597 	if (!freshest)
2598 		return 0;
2599 
2600 	/*
2601 	 * Validation of the freshest device provides the source of
2602 	 * validation for the remaining devices.
2603 	 */
2604 	rs->ti->error = "Unable to assemble array: Invalid superblocks";
2605 	if (super_validate(rs, freshest))
2606 		return -EINVAL;
2607 
2608 	if (validate_raid_redundancy(rs)) {
2609 		rs->ti->error = "Insufficient redundancy to activate array";
2610 		return -EINVAL;
2611 	}
2612 
2613 	rdev_for_each(rdev, mddev)
2614 		if (!test_bit(Journal, &rdev->flags) &&
2615 		    rdev != freshest &&
2616 		    super_validate(rs, rdev))
2617 			return -EINVAL;
2618 	return 0;
2619 }
2620 
2621 /*
2622  * Adjust data_offset and new_data_offset on all disk members of @rs
2623  * for out of place reshaping if requested by constructor
2624  *
2625  * We need free space at the beginning of each raid disk for forward
2626  * and at the end for backward reshapes which userspace has to provide
2627  * via remapping/reordering of space.
2628  */
2629 static int rs_adjust_data_offsets(struct raid_set *rs)
2630 {
2631 	sector_t data_offset = 0, new_data_offset = 0;
2632 	struct md_rdev *rdev;
2633 
2634 	/* Constructor did not request data offset change */
2635 	if (!test_bit(__CTR_FLAG_DATA_OFFSET, &rs->ctr_flags)) {
2636 		if (!rs_is_reshapable(rs))
2637 			goto out;
2638 
2639 		return 0;
2640 	}
2641 
2642 	/* HM FIXME: get In_Sync raid_dev? */
2643 	rdev = &rs->dev[0].rdev;
2644 
2645 	if (rs->delta_disks < 0) {
2646 		/*
2647 		 * Removing disks (reshaping backwards):
2648 		 *
2649 		 * - before reshape: data is at offset 0 and free space
2650 		 *		     is at end of each component LV
2651 		 *
2652 		 * - after reshape: data is at offset rs->data_offset != 0 on each component LV
2653 		 */
2654 		data_offset = 0;
2655 		new_data_offset = rs->data_offset;
2656 
2657 	} else if (rs->delta_disks > 0) {
2658 		/*
2659 		 * Adding disks (reshaping forwards):
2660 		 *
2661 		 * - before reshape: data is at offset rs->data_offset != 0 and
2662 		 *		     free space is at begin of each component LV
2663 		 *
2664 		 * - after reshape: data is at offset 0 on each component LV
2665 		 */
2666 		data_offset = rs->data_offset;
2667 		new_data_offset = 0;
2668 
2669 	} else {
2670 		/*
2671 		 * User space passes in 0 for data offset after having removed reshape space
2672 		 *
2673 		 * - or - (data offset != 0)
2674 		 *
2675 		 * Changing RAID layout or chunk size -> toggle offsets
2676 		 *
2677 		 * - before reshape: data is at offset rs->data_offset 0 and
2678 		 *		     free space is at end of each component LV
2679 		 *		     -or-
2680 		 *                   data is at offset rs->data_offset != 0 and
2681 		 *		     free space is at begin of each component LV
2682 		 *
2683 		 * - after reshape: data is at offset 0 if it was at offset != 0
2684 		 *                  or at offset != 0 if it was at offset 0
2685 		 *                  on each component LV
2686 		 *
2687 		 */
2688 		data_offset = rs->data_offset ? rdev->data_offset : 0;
2689 		new_data_offset = data_offset ? 0 : rs->data_offset;
2690 		set_bit(RT_FLAG_UPDATE_SBS, &rs->runtime_flags);
2691 	}
2692 
2693 	/*
2694 	 * Make sure we got a minimum amount of free sectors per device
2695 	 */
2696 	if (rs->data_offset &&
2697 	    bdev_nr_sectors(rdev->bdev) - rs->md.dev_sectors < MIN_FREE_RESHAPE_SPACE) {
2698 		rs->ti->error = data_offset ? "No space for forward reshape" :
2699 					      "No space for backward reshape";
2700 		return -ENOSPC;
2701 	}
2702 out:
2703 	/*
2704 	 * Raise recovery_cp in case data_offset != 0 to
2705 	 * avoid false recovery positives in the constructor.
2706 	 */
2707 	if (rs->md.recovery_cp < rs->md.dev_sectors)
2708 		rs->md.recovery_cp += rs->dev[0].rdev.data_offset;
2709 
2710 	/* Adjust data offsets on all rdevs but on any raid4/5/6 journal device */
2711 	rdev_for_each(rdev, &rs->md) {
2712 		if (!test_bit(Journal, &rdev->flags)) {
2713 			rdev->data_offset = data_offset;
2714 			rdev->new_data_offset = new_data_offset;
2715 		}
2716 	}
2717 
2718 	return 0;
2719 }
2720 
2721 /* Userpace reordered disks -> adjust raid_disk indexes in @rs */
2722 static void __reorder_raid_disk_indexes(struct raid_set *rs)
2723 {
2724 	int i = 0;
2725 	struct md_rdev *rdev;
2726 
2727 	rdev_for_each(rdev, &rs->md) {
2728 		if (!test_bit(Journal, &rdev->flags)) {
2729 			rdev->raid_disk = i++;
2730 			rdev->saved_raid_disk = rdev->new_raid_disk = -1;
2731 		}
2732 	}
2733 }
2734 
2735 /*
2736  * Setup @rs for takeover by a different raid level
2737  */
2738 static int rs_setup_takeover(struct raid_set *rs)
2739 {
2740 	struct mddev *mddev = &rs->md;
2741 	struct md_rdev *rdev;
2742 	unsigned int d = mddev->raid_disks = rs->raid_disks;
2743 	sector_t new_data_offset = rs->dev[0].rdev.data_offset ? 0 : rs->data_offset;
2744 
2745 	if (rt_is_raid10(rs->raid_type)) {
2746 		if (rs_is_raid0(rs)) {
2747 			/* Userpace reordered disks -> adjust raid_disk indexes */
2748 			__reorder_raid_disk_indexes(rs);
2749 
2750 			/* raid0 -> raid10_far layout */
2751 			mddev->layout = raid10_format_to_md_layout(rs, ALGORITHM_RAID10_FAR,
2752 								   rs->raid10_copies);
2753 		} else if (rs_is_raid1(rs))
2754 			/* raid1 -> raid10_near layout */
2755 			mddev->layout = raid10_format_to_md_layout(rs, ALGORITHM_RAID10_NEAR,
2756 								   rs->raid_disks);
2757 		else
2758 			return -EINVAL;
2759 
2760 	}
2761 
2762 	clear_bit(MD_ARRAY_FIRST_USE, &mddev->flags);
2763 	mddev->recovery_cp = MaxSector;
2764 
2765 	while (d--) {
2766 		rdev = &rs->dev[d].rdev;
2767 
2768 		if (test_bit(d, (void *) rs->rebuild_disks)) {
2769 			clear_bit(In_sync, &rdev->flags);
2770 			clear_bit(Faulty, &rdev->flags);
2771 			mddev->recovery_cp = rdev->recovery_offset = 0;
2772 			/* Bitmap has to be created when we do an "up" takeover */
2773 			set_bit(MD_ARRAY_FIRST_USE, &mddev->flags);
2774 		}
2775 
2776 		rdev->new_data_offset = new_data_offset;
2777 	}
2778 
2779 	return 0;
2780 }
2781 
2782 /* Prepare @rs for reshape */
2783 static int rs_prepare_reshape(struct raid_set *rs)
2784 {
2785 	bool reshape;
2786 	struct mddev *mddev = &rs->md;
2787 
2788 	if (rs_is_raid10(rs)) {
2789 		if (rs->raid_disks != mddev->raid_disks &&
2790 		    __is_raid10_near(mddev->layout) &&
2791 		    rs->raid10_copies &&
2792 		    rs->raid10_copies != __raid10_near_copies(mddev->layout)) {
2793 			/*
2794 			 * raid disk have to be multiple of data copies to allow this conversion,
2795 			 *
2796 			 * This is actually not a reshape it is a
2797 			 * rebuild of any additional mirrors per group
2798 			 */
2799 			if (rs->raid_disks % rs->raid10_copies) {
2800 				rs->ti->error = "Can't reshape raid10 mirror groups";
2801 				return -EINVAL;
2802 			}
2803 
2804 			/* Userpace reordered disks to add/remove mirrors -> adjust raid_disk indexes */
2805 			__reorder_raid_disk_indexes(rs);
2806 			mddev->layout = raid10_format_to_md_layout(rs, ALGORITHM_RAID10_NEAR,
2807 								   rs->raid10_copies);
2808 			mddev->new_layout = mddev->layout;
2809 			reshape = false;
2810 		} else
2811 			reshape = true;
2812 
2813 	} else if (rs_is_raid456(rs))
2814 		reshape = true;
2815 
2816 	else if (rs_is_raid1(rs)) {
2817 		if (rs->delta_disks) {
2818 			/* Process raid1 via delta_disks */
2819 			mddev->degraded = rs->delta_disks < 0 ? -rs->delta_disks : rs->delta_disks;
2820 			reshape = true;
2821 		} else {
2822 			/* Process raid1 without delta_disks */
2823 			mddev->raid_disks = rs->raid_disks;
2824 			reshape = false;
2825 		}
2826 	} else {
2827 		rs->ti->error = "Called with bogus raid type";
2828 		return -EINVAL;
2829 	}
2830 
2831 	if (reshape) {
2832 		set_bit(RT_FLAG_RESHAPE_RS, &rs->runtime_flags);
2833 		set_bit(RT_FLAG_UPDATE_SBS, &rs->runtime_flags);
2834 	} else if (mddev->raid_disks < rs->raid_disks)
2835 		/* Create new superblocks and bitmaps, if any new disks */
2836 		set_bit(RT_FLAG_UPDATE_SBS, &rs->runtime_flags);
2837 
2838 	return 0;
2839 }
2840 
2841 /*
2842  * Reshape:
2843  * - change raid layout
2844  * - change chunk size
2845  * - add disks
2846  * - remove disks
2847  */
2848 static int rs_setup_reshape(struct raid_set *rs)
2849 {
2850 	int r = 0;
2851 	unsigned int cur_raid_devs, d;
2852 	sector_t reshape_sectors = _get_reshape_sectors(rs);
2853 	struct mddev *mddev = &rs->md;
2854 	struct md_rdev *rdev;
2855 
2856 	mddev->delta_disks = rs->delta_disks;
2857 	cur_raid_devs = mddev->raid_disks;
2858 
2859 	/* Ignore impossible layout change whilst adding/removing disks */
2860 	if (mddev->delta_disks &&
2861 	    mddev->layout != mddev->new_layout) {
2862 		DMINFO("Ignoring invalid layout change with delta_disks=%d", rs->delta_disks);
2863 		mddev->new_layout = mddev->layout;
2864 	}
2865 
2866 	/*
2867 	 * Adjust array size:
2868 	 *
2869 	 * - in case of adding disk(s), array size has
2870 	 *   to grow after the disk adding reshape,
2871 	 *   which'll happen in the event handler;
2872 	 *   reshape will happen forward, so space has to
2873 	 *   be available at the beginning of each disk
2874 	 *
2875 	 * - in case of removing disk(s), array size
2876 	 *   has to shrink before starting the reshape,
2877 	 *   which'll happen here;
2878 	 *   reshape will happen backward, so space has to
2879 	 *   be available at the end of each disk
2880 	 *
2881 	 * - data_offset and new_data_offset are
2882 	 *   adjusted for aforementioned out of place
2883 	 *   reshaping based on userspace passing in
2884 	 *   the "data_offset <sectors>" key/value
2885 	 *   pair via the constructor
2886 	 */
2887 
2888 	/* Add disk(s) */
2889 	if (rs->delta_disks > 0) {
2890 		/* Prepare disks for check in raid4/5/6/10 {check|start}_reshape */
2891 		for (d = cur_raid_devs; d < rs->raid_disks; d++) {
2892 			rdev = &rs->dev[d].rdev;
2893 			clear_bit(In_sync, &rdev->flags);
2894 
2895 			/*
2896 			 * save_raid_disk needs to be -1, or recovery_offset will be set to 0
2897 			 * by md, which'll store that erroneously in the superblock on reshape
2898 			 */
2899 			rdev->saved_raid_disk = -1;
2900 			rdev->raid_disk = d;
2901 
2902 			rdev->sectors = mddev->dev_sectors;
2903 			rdev->recovery_offset = rs_is_raid1(rs) ? 0 : MaxSector;
2904 		}
2905 
2906 		mddev->reshape_backwards = 0; /* adding disk(s) -> forward reshape */
2907 
2908 	/* Remove disk(s) */
2909 	} else if (rs->delta_disks < 0) {
2910 		r = rs_set_dev_and_array_sectors(rs, rs->ti->len, true);
2911 		mddev->reshape_backwards = 1; /* removing disk(s) -> backward reshape */
2912 
2913 	/* Change layout and/or chunk size */
2914 	} else {
2915 		/*
2916 		 * Reshape layout (e.g. raid5_ls -> raid5_n) and/or chunk size:
2917 		 *
2918 		 * keeping number of disks and do layout change ->
2919 		 *
2920 		 * toggle reshape_backward depending on data_offset:
2921 		 *
2922 		 * - free space upfront -> reshape forward
2923 		 *
2924 		 * - free space at the end -> reshape backward
2925 		 *
2926 		 *
2927 		 * This utilizes free reshape space avoiding the need
2928 		 * for userspace to move (parts of) LV segments in
2929 		 * case of layout/chunksize change  (for disk
2930 		 * adding/removing reshape space has to be at
2931 		 * the proper address (see above with delta_disks):
2932 		 *
2933 		 * add disk(s)   -> begin
2934 		 * remove disk(s)-> end
2935 		 */
2936 		mddev->reshape_backwards = rs->dev[0].rdev.data_offset ? 0 : 1;
2937 	}
2938 
2939 	/*
2940 	 * Adjust device size for forward reshape
2941 	 * because md_finish_reshape() reduces it.
2942 	 */
2943 	if (!mddev->reshape_backwards)
2944 		rdev_for_each(rdev, &rs->md)
2945 			if (!test_bit(Journal, &rdev->flags))
2946 				rdev->sectors += reshape_sectors;
2947 
2948 	return r;
2949 }
2950 
2951 /*
2952  * If the md resync thread has updated superblock with max reshape position
2953  * at the end of a reshape but not (yet) reset the layout configuration
2954  * changes -> reset the latter.
2955  */
2956 static void rs_reset_inconclusive_reshape(struct raid_set *rs)
2957 {
2958 	if (!rs_is_reshaping(rs) && rs_is_layout_change(rs, true)) {
2959 		rs_set_cur(rs);
2960 		rs->md.delta_disks = 0;
2961 		rs->md.reshape_backwards = 0;
2962 	}
2963 }
2964 
2965 /*
2966  * Enable/disable discard support on RAID set depending on
2967  * RAID level and discard properties of underlying RAID members.
2968  */
2969 static void configure_discard_support(struct raid_set *rs)
2970 {
2971 	int i;
2972 	bool raid456;
2973 	struct dm_target *ti = rs->ti;
2974 
2975 	/*
2976 	 * XXX: RAID level 4,5,6 require zeroing for safety.
2977 	 */
2978 	raid456 = rs_is_raid456(rs);
2979 
2980 	for (i = 0; i < rs->raid_disks; i++) {
2981 		if (!rs->dev[i].rdev.bdev ||
2982 		    !bdev_max_discard_sectors(rs->dev[i].rdev.bdev))
2983 			return;
2984 
2985 		if (raid456) {
2986 			if (!devices_handle_discard_safely) {
2987 				DMERR("raid456 discard support disabled due to discard_zeroes_data uncertainty.");
2988 				DMERR("Set dm-raid.devices_handle_discard_safely=Y to override.");
2989 				return;
2990 			}
2991 		}
2992 	}
2993 
2994 	ti->num_discard_bios = 1;
2995 }
2996 
2997 /*
2998  * Construct a RAID0/1/10/4/5/6 mapping:
2999  * Args:
3000  *	<raid_type> <#raid_params> <raid_params>{0,}	\
3001  *	<#raid_devs> [<meta_dev1> <dev1>]{1,}
3002  *
3003  * <raid_params> varies by <raid_type>.	 See 'parse_raid_params' for
3004  * details on possible <raid_params>.
3005  *
3006  * Userspace is free to initialize the metadata devices, hence the superblocks to
3007  * enforce recreation based on the passed in table parameters.
3008  *
3009  */
3010 static int raid_ctr(struct dm_target *ti, unsigned int argc, char **argv)
3011 {
3012 	int r;
3013 	bool resize = false;
3014 	struct raid_type *rt;
3015 	unsigned int num_raid_params, num_raid_devs;
3016 	sector_t sb_array_sectors, rdev_sectors, reshape_sectors;
3017 	struct raid_set *rs = NULL;
3018 	const char *arg;
3019 	struct rs_layout rs_layout;
3020 	struct dm_arg_set as = { argc, argv }, as_nrd;
3021 	struct dm_arg _args[] = {
3022 		{ 0, as.argc, "Cannot understand number of raid parameters" },
3023 		{ 1, 254, "Cannot understand number of raid devices parameters" }
3024 	};
3025 
3026 	arg = dm_shift_arg(&as);
3027 	if (!arg) {
3028 		ti->error = "No arguments";
3029 		return -EINVAL;
3030 	}
3031 
3032 	rt = get_raid_type(arg);
3033 	if (!rt) {
3034 		ti->error = "Unrecognised raid_type";
3035 		return -EINVAL;
3036 	}
3037 
3038 	/* Must have <#raid_params> */
3039 	if (dm_read_arg_group(_args, &as, &num_raid_params, &ti->error))
3040 		return -EINVAL;
3041 
3042 	/* number of raid device tupples <meta_dev data_dev> */
3043 	as_nrd = as;
3044 	dm_consume_args(&as_nrd, num_raid_params);
3045 	_args[1].max = (as_nrd.argc - 1) / 2;
3046 	if (dm_read_arg(_args + 1, &as_nrd, &num_raid_devs, &ti->error))
3047 		return -EINVAL;
3048 
3049 	if (!__within_range(num_raid_devs, 1, MAX_RAID_DEVICES)) {
3050 		ti->error = "Invalid number of supplied raid devices";
3051 		return -EINVAL;
3052 	}
3053 
3054 	rs = raid_set_alloc(ti, rt, num_raid_devs);
3055 	if (IS_ERR(rs))
3056 		return PTR_ERR(rs);
3057 
3058 	r = parse_raid_params(rs, &as, num_raid_params);
3059 	if (r)
3060 		goto bad;
3061 
3062 	r = parse_dev_params(rs, &as);
3063 	if (r)
3064 		goto bad;
3065 
3066 	rs->md.sync_super = super_sync;
3067 
3068 	/*
3069 	 * Calculate ctr requested array and device sizes to allow
3070 	 * for superblock analysis needing device sizes defined.
3071 	 *
3072 	 * Any existing superblock will overwrite the array and device sizes
3073 	 */
3074 	r = rs_set_dev_and_array_sectors(rs, rs->ti->len, false);
3075 	if (r)
3076 		goto bad;
3077 
3078 	/* Memorize just calculated, potentially larger sizes to grow the raid set in preresume */
3079 	rs->array_sectors = rs->md.array_sectors;
3080 	rs->dev_sectors = rs->md.dev_sectors;
3081 
3082 	/*
3083 	 * Backup any new raid set level, layout, ...
3084 	 * requested to be able to compare to superblock
3085 	 * members for conversion decisions.
3086 	 */
3087 	rs_config_backup(rs, &rs_layout);
3088 
3089 	r = analyse_superblocks(ti, rs);
3090 	if (r)
3091 		goto bad;
3092 
3093 	/* All in-core metadata now as of current superblocks after calling analyse_superblocks() */
3094 	sb_array_sectors = rs->md.array_sectors;
3095 	rdev_sectors = __rdev_sectors(rs);
3096 	if (!rdev_sectors) {
3097 		ti->error = "Invalid rdev size";
3098 		r = -EINVAL;
3099 		goto bad;
3100 	}
3101 
3102 
3103 	reshape_sectors = _get_reshape_sectors(rs);
3104 	if (rs->dev_sectors != rdev_sectors) {
3105 		resize = (rs->dev_sectors != rdev_sectors - reshape_sectors);
3106 		if (rs->dev_sectors > rdev_sectors - reshape_sectors)
3107 			set_bit(RT_FLAG_RS_GROW, &rs->runtime_flags);
3108 	}
3109 
3110 	INIT_WORK(&rs->md.event_work, do_table_event);
3111 	ti->private = rs;
3112 	ti->num_flush_bios = 1;
3113 	ti->needs_bio_set_dev = true;
3114 
3115 	/* Restore any requested new layout for conversion decision */
3116 	rs_config_restore(rs, &rs_layout);
3117 
3118 	/*
3119 	 * Now that we have any superblock metadata available,
3120 	 * check for new, recovering, reshaping, to be taken over,
3121 	 * to be reshaped or an existing, unchanged raid set to
3122 	 * run in sequence.
3123 	 */
3124 	if (test_bit(MD_ARRAY_FIRST_USE, &rs->md.flags)) {
3125 		/* A new raid6 set has to be recovered to ensure proper parity and Q-Syndrome */
3126 		if (rs_is_raid6(rs) &&
3127 		    test_bit(__CTR_FLAG_NOSYNC, &rs->ctr_flags)) {
3128 			ti->error = "'nosync' not allowed for new raid6 set";
3129 			r = -EINVAL;
3130 			goto bad;
3131 		}
3132 		rs_setup_recovery(rs, 0);
3133 		set_bit(RT_FLAG_UPDATE_SBS, &rs->runtime_flags);
3134 		rs_set_new(rs);
3135 	} else if (rs_is_recovering(rs)) {
3136 		/* A recovering raid set may be resized */
3137 		goto size_check;
3138 	} else if (rs_is_reshaping(rs)) {
3139 		/* Have to reject size change request during reshape */
3140 		if (resize) {
3141 			ti->error = "Can't resize a reshaping raid set";
3142 			r = -EPERM;
3143 			goto bad;
3144 		}
3145 		/* skip setup rs */
3146 	} else if (rs_takeover_requested(rs)) {
3147 		if (rs_is_reshaping(rs)) {
3148 			ti->error = "Can't takeover a reshaping raid set";
3149 			r = -EPERM;
3150 			goto bad;
3151 		}
3152 
3153 		/* We can't takeover a journaled raid4/5/6 */
3154 		if (test_bit(__CTR_FLAG_JOURNAL_DEV, &rs->ctr_flags)) {
3155 			ti->error = "Can't takeover a journaled raid4/5/6 set";
3156 			r = -EPERM;
3157 			goto bad;
3158 		}
3159 
3160 		/*
3161 		 * If a takeover is needed, userspace sets any additional
3162 		 * devices to rebuild and we can check for a valid request here.
3163 		 *
3164 		 * If acceptable, set the level to the new requested
3165 		 * one, prohibit requesting recovery, allow the raid
3166 		 * set to run and store superblocks during resume.
3167 		 */
3168 		r = rs_check_takeover(rs);
3169 		if (r)
3170 			goto bad;
3171 
3172 		r = rs_setup_takeover(rs);
3173 		if (r)
3174 			goto bad;
3175 
3176 		set_bit(RT_FLAG_UPDATE_SBS, &rs->runtime_flags);
3177 		/* Takeover ain't recovery, so disable recovery */
3178 		rs_setup_recovery(rs, MaxSector);
3179 		rs_set_new(rs);
3180 	} else if (rs_reshape_requested(rs)) {
3181 		/* Only request grow on raid set size extensions, not on reshapes. */
3182 		clear_bit(RT_FLAG_RS_GROW, &rs->runtime_flags);
3183 
3184 		/*
3185 		 * No need to check for 'ongoing' takeover here, because takeover
3186 		 * is an instant operation as oposed to an ongoing reshape.
3187 		 */
3188 
3189 		/* We can't reshape a journaled raid4/5/6 */
3190 		if (test_bit(__CTR_FLAG_JOURNAL_DEV, &rs->ctr_flags)) {
3191 			ti->error = "Can't reshape a journaled raid4/5/6 set";
3192 			r = -EPERM;
3193 			goto bad;
3194 		}
3195 
3196 		/* Out-of-place space has to be available to allow for a reshape unless raid1! */
3197 		if (reshape_sectors || rs_is_raid1(rs)) {
3198 			/*
3199 			 * We can only prepare for a reshape here, because the
3200 			 * raid set needs to run to provide the respective reshape
3201 			 * check functions via its MD personality instance.
3202 			 *
3203 			 * So do the reshape check after md_run() succeeded.
3204 			 */
3205 			r = rs_prepare_reshape(rs);
3206 			if (r)
3207 				goto bad;
3208 
3209 			/* Reshaping ain't recovery, so disable recovery */
3210 			rs_setup_recovery(rs, MaxSector);
3211 		}
3212 		rs_set_cur(rs);
3213 	} else {
3214 size_check:
3215 		/* May not set recovery when a device rebuild is requested */
3216 		if (test_bit(__CTR_FLAG_REBUILD, &rs->ctr_flags)) {
3217 			clear_bit(RT_FLAG_RS_GROW, &rs->runtime_flags);
3218 			set_bit(RT_FLAG_UPDATE_SBS, &rs->runtime_flags);
3219 			rs_setup_recovery(rs, MaxSector);
3220 		} else if (test_bit(RT_FLAG_RS_GROW, &rs->runtime_flags)) {
3221 			/*
3222 			 * Set raid set to current size, i.e. size as of
3223 			 * superblocks to grow to larger size in preresume.
3224 			 */
3225 			r = rs_set_dev_and_array_sectors(rs, sb_array_sectors, false);
3226 			if (r)
3227 				goto bad;
3228 
3229 			rs_setup_recovery(rs, rs->md.recovery_cp < rs->md.dev_sectors ? rs->md.recovery_cp : rs->md.dev_sectors);
3230 		} else {
3231 			/* This is no size change or it is shrinking, update size and record in superblocks */
3232 			r = rs_set_dev_and_array_sectors(rs, rs->ti->len, false);
3233 			if (r)
3234 				goto bad;
3235 
3236 			if (sb_array_sectors > rs->array_sectors)
3237 				set_bit(RT_FLAG_UPDATE_SBS, &rs->runtime_flags);
3238 		}
3239 		rs_set_cur(rs);
3240 	}
3241 
3242 	/* If constructor requested it, change data and new_data offsets */
3243 	r = rs_adjust_data_offsets(rs);
3244 	if (r)
3245 		goto bad;
3246 
3247 	/* Catch any inconclusive reshape superblock content. */
3248 	rs_reset_inconclusive_reshape(rs);
3249 
3250 	/* Start raid set read-only and assumed clean to change in raid_resume() */
3251 	rs->md.ro = 1;
3252 	rs->md.in_sync = 1;
3253 
3254 	/* Has to be held on running the array */
3255 	mddev_suspend_and_lock_nointr(&rs->md);
3256 
3257 	/* Keep array frozen until resume. */
3258 	md_frozen_sync_thread(&rs->md);
3259 
3260 	r = md_run(&rs->md);
3261 	rs->md.in_sync = 0; /* Assume already marked dirty */
3262 	if (r) {
3263 		ti->error = "Failed to run raid array";
3264 		mddev_unlock(&rs->md);
3265 		goto bad;
3266 	}
3267 
3268 	r = md_start(&rs->md);
3269 	if (r) {
3270 		ti->error = "Failed to start raid array";
3271 		goto bad_unlock;
3272 	}
3273 
3274 	/* If raid4/5/6 journal mode explicitly requested (only possible with journal dev) -> set it */
3275 	if (test_bit(__CTR_FLAG_JOURNAL_MODE, &rs->ctr_flags)) {
3276 		r = r5c_journal_mode_set(&rs->md, rs->journal_dev.mode);
3277 		if (r) {
3278 			ti->error = "Failed to set raid4/5/6 journal mode";
3279 			goto bad_unlock;
3280 		}
3281 	}
3282 
3283 	set_bit(RT_FLAG_RS_SUSPENDED, &rs->runtime_flags);
3284 
3285 	/* Try to adjust the raid4/5/6 stripe cache size to the stripe size */
3286 	if (rs_is_raid456(rs)) {
3287 		r = rs_set_raid456_stripe_cache(rs);
3288 		if (r)
3289 			goto bad_unlock;
3290 	}
3291 
3292 	/* Now do an early reshape check */
3293 	if (test_bit(RT_FLAG_RESHAPE_RS, &rs->runtime_flags)) {
3294 		r = rs_check_reshape(rs);
3295 		if (r)
3296 			goto bad_unlock;
3297 
3298 		/* Restore new, ctr requested layout to perform check */
3299 		rs_config_restore(rs, &rs_layout);
3300 
3301 		if (rs->md.pers->start_reshape) {
3302 			r = rs->md.pers->check_reshape(&rs->md);
3303 			if (r) {
3304 				ti->error = "Reshape check failed";
3305 				goto bad_unlock;
3306 			}
3307 		}
3308 	}
3309 
3310 	/* Disable/enable discard support on raid set. */
3311 	configure_discard_support(rs);
3312 	rs->md.dm_gendisk = ti->table->md->disk;
3313 
3314 	mddev_unlock(&rs->md);
3315 	return 0;
3316 
3317 bad_unlock:
3318 	md_stop(&rs->md);
3319 	mddev_unlock(&rs->md);
3320 bad:
3321 	raid_set_free(rs);
3322 
3323 	return r;
3324 }
3325 
3326 static void raid_dtr(struct dm_target *ti)
3327 {
3328 	struct raid_set *rs = ti->private;
3329 
3330 	mddev_lock_nointr(&rs->md);
3331 	md_stop(&rs->md);
3332 	rs->md.dm_gendisk = NULL;
3333 	mddev_unlock(&rs->md);
3334 
3335 	if (work_pending(&rs->md.event_work))
3336 		flush_work(&rs->md.event_work);
3337 	raid_set_free(rs);
3338 }
3339 
3340 static int raid_map(struct dm_target *ti, struct bio *bio)
3341 {
3342 	struct raid_set *rs = ti->private;
3343 	struct mddev *mddev = &rs->md;
3344 
3345 	/*
3346 	 * If we're reshaping to add disk(s), ti->len and
3347 	 * mddev->array_sectors will differ during the process
3348 	 * (ti->len > mddev->array_sectors), so we have to requeue
3349 	 * bios with addresses > mddev->array_sectors here or
3350 	 * there will occur accesses past EOD of the component
3351 	 * data images thus erroring the raid set.
3352 	 */
3353 	if (unlikely(bio_has_data(bio) && bio_end_sector(bio) > mddev->array_sectors))
3354 		return DM_MAPIO_REQUEUE;
3355 
3356 	if (unlikely(!md_handle_request(mddev, bio)))
3357 		return DM_MAPIO_REQUEUE;
3358 
3359 	return DM_MAPIO_SUBMITTED;
3360 }
3361 
3362 /* Return sync state string for @state */
3363 enum sync_state { st_frozen, st_reshape, st_resync, st_check, st_repair, st_recover, st_idle };
3364 static const char *sync_str(enum sync_state state)
3365 {
3366 	/* Has to be in above sync_state order! */
3367 	static const char *sync_strs[] = {
3368 		"frozen",
3369 		"reshape",
3370 		"resync",
3371 		"check",
3372 		"repair",
3373 		"recover",
3374 		"idle"
3375 	};
3376 
3377 	return __within_range(state, 0, ARRAY_SIZE(sync_strs) - 1) ? sync_strs[state] : "undef";
3378 };
3379 
3380 /* Return enum sync_state for @mddev derived from @recovery flags */
3381 static enum sync_state decipher_sync_action(struct mddev *mddev, unsigned long recovery)
3382 {
3383 	if (test_bit(MD_RECOVERY_FROZEN, &recovery))
3384 		return st_frozen;
3385 
3386 	/* The MD sync thread can be done with io or be interrupted but still be running */
3387 	if (!test_bit(MD_RECOVERY_DONE, &recovery) &&
3388 	    (test_bit(MD_RECOVERY_RUNNING, &recovery) ||
3389 	     (!mddev->ro && test_bit(MD_RECOVERY_NEEDED, &recovery)))) {
3390 		if (test_bit(MD_RECOVERY_RESHAPE, &recovery))
3391 			return st_reshape;
3392 
3393 		if (test_bit(MD_RECOVERY_SYNC, &recovery)) {
3394 			if (!test_bit(MD_RECOVERY_REQUESTED, &recovery))
3395 				return st_resync;
3396 			if (test_bit(MD_RECOVERY_CHECK, &recovery))
3397 				return st_check;
3398 			return st_repair;
3399 		}
3400 
3401 		if (test_bit(MD_RECOVERY_RECOVER, &recovery))
3402 			return st_recover;
3403 
3404 		if (mddev->reshape_position != MaxSector)
3405 			return st_reshape;
3406 	}
3407 
3408 	return st_idle;
3409 }
3410 
3411 /*
3412  * Return status string for @rdev
3413  *
3414  * Status characters:
3415  *
3416  *  'D' = Dead/Failed raid set component or raid4/5/6 journal device
3417  *  'a' = Alive but not in-sync raid set component _or_ alive raid4/5/6 'write_back' journal device
3418  *  'A' = Alive and in-sync raid set component _or_ alive raid4/5/6 'write_through' journal device
3419  *  '-' = Non-existing device (i.e. uspace passed '- -' into the ctr)
3420  */
3421 static const char *__raid_dev_status(struct raid_set *rs, struct md_rdev *rdev)
3422 {
3423 	if (!rdev->bdev)
3424 		return "-";
3425 	else if (test_bit(Faulty, &rdev->flags))
3426 		return "D";
3427 	else if (test_bit(Journal, &rdev->flags))
3428 		return (rs->journal_dev.mode == R5C_JOURNAL_MODE_WRITE_THROUGH) ? "A" : "a";
3429 	else if (test_bit(RT_FLAG_RS_RESYNCING, &rs->runtime_flags) ||
3430 		 (!test_bit(RT_FLAG_RS_IN_SYNC, &rs->runtime_flags) &&
3431 		  !test_bit(In_sync, &rdev->flags)))
3432 		return "a";
3433 	else
3434 		return "A";
3435 }
3436 
3437 /* Helper to return resync/reshape progress for @rs and runtime flags for raid set in sync / resynching */
3438 static sector_t rs_get_progress(struct raid_set *rs, unsigned long recovery,
3439 				enum sync_state state, sector_t resync_max_sectors)
3440 {
3441 	sector_t r;
3442 	struct mddev *mddev = &rs->md;
3443 
3444 	clear_bit(RT_FLAG_RS_IN_SYNC, &rs->runtime_flags);
3445 	clear_bit(RT_FLAG_RS_RESYNCING, &rs->runtime_flags);
3446 
3447 	if (rs_is_raid0(rs)) {
3448 		r = resync_max_sectors;
3449 		set_bit(RT_FLAG_RS_IN_SYNC, &rs->runtime_flags);
3450 
3451 	} else {
3452 		if (state == st_idle && !test_bit(MD_RECOVERY_INTR, &recovery))
3453 			r = mddev->recovery_cp;
3454 		else
3455 			r = mddev->curr_resync_completed;
3456 
3457 		if (state == st_idle && r >= resync_max_sectors) {
3458 			/*
3459 			 * Sync complete.
3460 			 */
3461 			/* In case we have finished recovering, the array is in sync. */
3462 			if (test_bit(MD_RECOVERY_RECOVER, &recovery))
3463 				set_bit(RT_FLAG_RS_IN_SYNC, &rs->runtime_flags);
3464 
3465 		} else if (state == st_recover)
3466 			/*
3467 			 * In case we are recovering, the array is not in sync
3468 			 * and health chars should show the recovering legs.
3469 			 *
3470 			 * Already retrieved recovery offset from curr_resync_completed above.
3471 			 */
3472 			;
3473 
3474 		else if (state == st_resync || state == st_reshape)
3475 			/*
3476 			 * If "resync/reshape" is occurring, the raid set
3477 			 * is or may be out of sync hence the health
3478 			 * characters shall be 'a'.
3479 			 */
3480 			set_bit(RT_FLAG_RS_RESYNCING, &rs->runtime_flags);
3481 
3482 		else if (state == st_check || state == st_repair)
3483 			/*
3484 			 * If "check" or "repair" is occurring, the raid set has
3485 			 * undergone an initial sync and the health characters
3486 			 * should not be 'a' anymore.
3487 			 */
3488 			set_bit(RT_FLAG_RS_IN_SYNC, &rs->runtime_flags);
3489 
3490 		else if (test_bit(MD_RECOVERY_NEEDED, &recovery))
3491 			/*
3492 			 * We are idle and recovery is needed, prevent 'A' chars race
3493 			 * caused by components still set to in-sync by constructor.
3494 			 */
3495 			set_bit(RT_FLAG_RS_RESYNCING, &rs->runtime_flags);
3496 
3497 		else {
3498 			/*
3499 			 * We are idle and the raid set may be doing an initial
3500 			 * sync, or it may be rebuilding individual components.
3501 			 * If all the devices are In_sync, then it is the raid set
3502 			 * that is being initialized.
3503 			 */
3504 			struct md_rdev *rdev;
3505 
3506 			set_bit(RT_FLAG_RS_IN_SYNC, &rs->runtime_flags);
3507 			rdev_for_each(rdev, mddev)
3508 				if (!test_bit(Journal, &rdev->flags) &&
3509 				    !test_bit(In_sync, &rdev->flags)) {
3510 					clear_bit(RT_FLAG_RS_IN_SYNC, &rs->runtime_flags);
3511 					break;
3512 				}
3513 		}
3514 	}
3515 
3516 	return min(r, resync_max_sectors);
3517 }
3518 
3519 /* Helper to return @dev name or "-" if !@dev */
3520 static const char *__get_dev_name(struct dm_dev *dev)
3521 {
3522 	return dev ? dev->name : "-";
3523 }
3524 
3525 static void raid_status(struct dm_target *ti, status_type_t type,
3526 			unsigned int status_flags, char *result, unsigned int maxlen)
3527 {
3528 	struct raid_set *rs = ti->private;
3529 	struct mddev *mddev = &rs->md;
3530 	struct r5conf *conf = rs_is_raid456(rs) ? mddev->private : NULL;
3531 	int i, max_nr_stripes = conf ? conf->max_nr_stripes : 0;
3532 	unsigned long recovery;
3533 	unsigned int raid_param_cnt = 1; /* at least 1 for chunksize */
3534 	unsigned int sz = 0;
3535 	unsigned int rebuild_writemostly_count = 0;
3536 	sector_t progress, resync_max_sectors, resync_mismatches;
3537 	enum sync_state state;
3538 	struct raid_type *rt;
3539 
3540 	switch (type) {
3541 	case STATUSTYPE_INFO:
3542 		/* *Should* always succeed */
3543 		rt = get_raid_type_by_ll(mddev->new_level, mddev->new_layout);
3544 		if (!rt)
3545 			return;
3546 
3547 		DMEMIT("%s %d ", rt->name, mddev->raid_disks);
3548 
3549 		/* Access most recent mddev properties for status output */
3550 		smp_rmb();
3551 		/* Get sensible max sectors even if raid set not yet started */
3552 		resync_max_sectors = test_bit(RT_FLAG_RS_PRERESUMED, &rs->runtime_flags) ?
3553 				      mddev->resync_max_sectors : mddev->dev_sectors;
3554 		recovery = rs->md.recovery;
3555 		state = decipher_sync_action(mddev, recovery);
3556 		progress = rs_get_progress(rs, recovery, state, resync_max_sectors);
3557 		resync_mismatches = mddev->last_sync_action == ACTION_CHECK ?
3558 				    atomic64_read(&mddev->resync_mismatches) : 0;
3559 
3560 		/* HM FIXME: do we want another state char for raid0? It shows 'D'/'A'/'-' now */
3561 		for (i = 0; i < rs->raid_disks; i++)
3562 			DMEMIT(__raid_dev_status(rs, &rs->dev[i].rdev));
3563 
3564 		/*
3565 		 * In-sync/Reshape ratio:
3566 		 *  The in-sync ratio shows the progress of:
3567 		 *   - Initializing the raid set
3568 		 *   - Rebuilding a subset of devices of the raid set
3569 		 *  The user can distinguish between the two by referring
3570 		 *  to the status characters.
3571 		 *
3572 		 *  The reshape ratio shows the progress of
3573 		 *  changing the raid layout or the number of
3574 		 *  disks of a raid set
3575 		 */
3576 		DMEMIT(" %llu/%llu", (unsigned long long) progress,
3577 				     (unsigned long long) resync_max_sectors);
3578 
3579 		/*
3580 		 * v1.5.0+:
3581 		 *
3582 		 * Sync action:
3583 		 *   See Documentation/admin-guide/device-mapper/dm-raid.rst for
3584 		 *   information on each of these states.
3585 		 */
3586 		DMEMIT(" %s", sync_str(state));
3587 
3588 		/*
3589 		 * v1.5.0+:
3590 		 *
3591 		 * resync_mismatches/mismatch_cnt
3592 		 *   This field shows the number of discrepancies found when
3593 		 *   performing a "check" of the raid set.
3594 		 */
3595 		DMEMIT(" %llu", (unsigned long long) resync_mismatches);
3596 
3597 		/*
3598 		 * v1.9.0+:
3599 		 *
3600 		 * data_offset (needed for out of space reshaping)
3601 		 *   This field shows the data offset into the data
3602 		 *   image LV where the first stripes data starts.
3603 		 *
3604 		 * We keep data_offset equal on all raid disks of the set,
3605 		 * so retrieving it from the first raid disk is sufficient.
3606 		 */
3607 		DMEMIT(" %llu", (unsigned long long) rs->dev[0].rdev.data_offset);
3608 
3609 		/*
3610 		 * v1.10.0+:
3611 		 */
3612 		DMEMIT(" %s", test_bit(__CTR_FLAG_JOURNAL_DEV, &rs->ctr_flags) ?
3613 			      __raid_dev_status(rs, &rs->journal_dev.rdev) : "-");
3614 		break;
3615 
3616 	case STATUSTYPE_TABLE:
3617 		/* Report the table line string you would use to construct this raid set */
3618 
3619 		/*
3620 		 * Count any rebuild or writemostly argument pairs and subtract the
3621 		 * hweight count being added below of any rebuild and writemostly ctr flags.
3622 		 */
3623 		for (i = 0; i < rs->raid_disks; i++) {
3624 			rebuild_writemostly_count += (test_bit(i, (void *) rs->rebuild_disks) ? 2 : 0) +
3625 						     (test_bit(WriteMostly, &rs->dev[i].rdev.flags) ? 2 : 0);
3626 		}
3627 		rebuild_writemostly_count -= (test_bit(__CTR_FLAG_REBUILD, &rs->ctr_flags) ? 2 : 0) +
3628 					     (test_bit(__CTR_FLAG_WRITE_MOSTLY, &rs->ctr_flags) ? 2 : 0);
3629 		/* Calculate raid parameter count based on ^ rebuild/writemostly argument counts and ctr flags set. */
3630 		raid_param_cnt += rebuild_writemostly_count +
3631 				  hweight32(rs->ctr_flags & CTR_FLAG_OPTIONS_NO_ARGS) +
3632 				  hweight32(rs->ctr_flags & CTR_FLAG_OPTIONS_ONE_ARG) * 2;
3633 		/* Emit table line */
3634 		/* This has to be in the documented order for userspace! */
3635 		DMEMIT("%s %u %u", rs->raid_type->name, raid_param_cnt, mddev->new_chunk_sectors);
3636 		if (test_bit(__CTR_FLAG_SYNC, &rs->ctr_flags))
3637 			DMEMIT(" %s", dm_raid_arg_name_by_flag(CTR_FLAG_SYNC));
3638 		if (test_bit(__CTR_FLAG_NOSYNC, &rs->ctr_flags))
3639 			DMEMIT(" %s", dm_raid_arg_name_by_flag(CTR_FLAG_NOSYNC));
3640 		if (test_bit(__CTR_FLAG_REBUILD, &rs->ctr_flags))
3641 			for (i = 0; i < rs->raid_disks; i++)
3642 				if (test_bit(i, (void *) rs->rebuild_disks))
3643 					DMEMIT(" %s %u", dm_raid_arg_name_by_flag(CTR_FLAG_REBUILD), i);
3644 		if (test_bit(__CTR_FLAG_DAEMON_SLEEP, &rs->ctr_flags))
3645 			DMEMIT(" %s %lu", dm_raid_arg_name_by_flag(CTR_FLAG_DAEMON_SLEEP),
3646 					  mddev->bitmap_info.daemon_sleep);
3647 		if (test_bit(__CTR_FLAG_MIN_RECOVERY_RATE, &rs->ctr_flags))
3648 			DMEMIT(" %s %d", dm_raid_arg_name_by_flag(CTR_FLAG_MIN_RECOVERY_RATE),
3649 					 mddev->sync_speed_min);
3650 		if (test_bit(__CTR_FLAG_MAX_RECOVERY_RATE, &rs->ctr_flags))
3651 			DMEMIT(" %s %d", dm_raid_arg_name_by_flag(CTR_FLAG_MAX_RECOVERY_RATE),
3652 					 mddev->sync_speed_max);
3653 		if (test_bit(__CTR_FLAG_WRITE_MOSTLY, &rs->ctr_flags))
3654 			for (i = 0; i < rs->raid_disks; i++)
3655 				if (test_bit(WriteMostly, &rs->dev[i].rdev.flags))
3656 					DMEMIT(" %s %d", dm_raid_arg_name_by_flag(CTR_FLAG_WRITE_MOSTLY),
3657 					       rs->dev[i].rdev.raid_disk);
3658 		if (test_bit(__CTR_FLAG_MAX_WRITE_BEHIND, &rs->ctr_flags))
3659 			DMEMIT(" %s %lu", dm_raid_arg_name_by_flag(CTR_FLAG_MAX_WRITE_BEHIND),
3660 					  mddev->bitmap_info.max_write_behind);
3661 		if (test_bit(__CTR_FLAG_STRIPE_CACHE, &rs->ctr_flags))
3662 			DMEMIT(" %s %d", dm_raid_arg_name_by_flag(CTR_FLAG_STRIPE_CACHE),
3663 					 max_nr_stripes);
3664 		if (test_bit(__CTR_FLAG_REGION_SIZE, &rs->ctr_flags))
3665 			DMEMIT(" %s %llu", dm_raid_arg_name_by_flag(CTR_FLAG_REGION_SIZE),
3666 					   (unsigned long long) to_sector(mddev->bitmap_info.chunksize));
3667 		if (test_bit(__CTR_FLAG_RAID10_COPIES, &rs->ctr_flags))
3668 			DMEMIT(" %s %d", dm_raid_arg_name_by_flag(CTR_FLAG_RAID10_COPIES),
3669 					 raid10_md_layout_to_copies(mddev->layout));
3670 		if (test_bit(__CTR_FLAG_RAID10_FORMAT, &rs->ctr_flags))
3671 			DMEMIT(" %s %s", dm_raid_arg_name_by_flag(CTR_FLAG_RAID10_FORMAT),
3672 					 raid10_md_layout_to_format(mddev->layout));
3673 		if (test_bit(__CTR_FLAG_DELTA_DISKS, &rs->ctr_flags))
3674 			DMEMIT(" %s %d", dm_raid_arg_name_by_flag(CTR_FLAG_DELTA_DISKS),
3675 					 max(rs->delta_disks, mddev->delta_disks));
3676 		if (test_bit(__CTR_FLAG_DATA_OFFSET, &rs->ctr_flags))
3677 			DMEMIT(" %s %llu", dm_raid_arg_name_by_flag(CTR_FLAG_DATA_OFFSET),
3678 					   (unsigned long long) rs->data_offset);
3679 		if (test_bit(__CTR_FLAG_JOURNAL_DEV, &rs->ctr_flags))
3680 			DMEMIT(" %s %s", dm_raid_arg_name_by_flag(CTR_FLAG_JOURNAL_DEV),
3681 					__get_dev_name(rs->journal_dev.dev));
3682 		if (test_bit(__CTR_FLAG_JOURNAL_MODE, &rs->ctr_flags))
3683 			DMEMIT(" %s %s", dm_raid_arg_name_by_flag(CTR_FLAG_JOURNAL_MODE),
3684 					 md_journal_mode_to_dm_raid(rs->journal_dev.mode));
3685 		DMEMIT(" %d", rs->raid_disks);
3686 		for (i = 0; i < rs->raid_disks; i++)
3687 			DMEMIT(" %s %s", __get_dev_name(rs->dev[i].meta_dev),
3688 					 __get_dev_name(rs->dev[i].data_dev));
3689 		break;
3690 
3691 	case STATUSTYPE_IMA:
3692 		rt = get_raid_type_by_ll(mddev->new_level, mddev->new_layout);
3693 		if (!rt)
3694 			return;
3695 
3696 		DMEMIT_TARGET_NAME_VERSION(ti->type);
3697 		DMEMIT(",raid_type=%s,raid_disks=%d", rt->name, mddev->raid_disks);
3698 
3699 		/* Access most recent mddev properties for status output */
3700 		smp_rmb();
3701 		recovery = rs->md.recovery;
3702 		state = decipher_sync_action(mddev, recovery);
3703 		DMEMIT(",raid_state=%s", sync_str(state));
3704 
3705 		for (i = 0; i < rs->raid_disks; i++) {
3706 			DMEMIT(",raid_device_%d_status=", i);
3707 			DMEMIT(__raid_dev_status(rs, &rs->dev[i].rdev));
3708 		}
3709 
3710 		if (rt_is_raid456(rt)) {
3711 			DMEMIT(",journal_dev_mode=");
3712 			switch (rs->journal_dev.mode) {
3713 			case R5C_JOURNAL_MODE_WRITE_THROUGH:
3714 				DMEMIT("%s",
3715 				       _raid456_journal_mode[R5C_JOURNAL_MODE_WRITE_THROUGH].param);
3716 				break;
3717 			case R5C_JOURNAL_MODE_WRITE_BACK:
3718 				DMEMIT("%s",
3719 				       _raid456_journal_mode[R5C_JOURNAL_MODE_WRITE_BACK].param);
3720 				break;
3721 			default:
3722 				DMEMIT("invalid");
3723 				break;
3724 			}
3725 		}
3726 		DMEMIT(";");
3727 		break;
3728 	}
3729 }
3730 
3731 static int raid_message(struct dm_target *ti, unsigned int argc, char **argv,
3732 			char *result, unsigned int maxlen)
3733 {
3734 	struct raid_set *rs = ti->private;
3735 	struct mddev *mddev = &rs->md;
3736 	int ret = 0;
3737 
3738 	if (!mddev->pers || !mddev->pers->sync_request)
3739 		return -EINVAL;
3740 
3741 	if (test_bit(RT_FLAG_RS_SUSPENDED, &rs->runtime_flags) ||
3742 	    test_bit(RT_FLAG_RS_FROZEN, &rs->runtime_flags))
3743 		return -EBUSY;
3744 
3745 	if (!strcasecmp(argv[0], "frozen")) {
3746 		ret = mddev_lock(mddev);
3747 		if (ret)
3748 			return ret;
3749 
3750 		md_frozen_sync_thread(mddev);
3751 		mddev_unlock(mddev);
3752 	} else if (!strcasecmp(argv[0], "idle")) {
3753 		ret = mddev_lock(mddev);
3754 		if (ret)
3755 			return ret;
3756 
3757 		md_idle_sync_thread(mddev);
3758 		mddev_unlock(mddev);
3759 	}
3760 
3761 	clear_bit(MD_RECOVERY_FROZEN, &mddev->recovery);
3762 	if (decipher_sync_action(mddev, mddev->recovery) != st_idle)
3763 		return -EBUSY;
3764 	else if (!strcasecmp(argv[0], "resync"))
3765 		; /* MD_RECOVERY_NEEDED set below */
3766 	else if (!strcasecmp(argv[0], "recover"))
3767 		set_bit(MD_RECOVERY_RECOVER, &mddev->recovery);
3768 	else {
3769 		if (!strcasecmp(argv[0], "check")) {
3770 			set_bit(MD_RECOVERY_CHECK, &mddev->recovery);
3771 			set_bit(MD_RECOVERY_REQUESTED, &mddev->recovery);
3772 			set_bit(MD_RECOVERY_SYNC, &mddev->recovery);
3773 		} else if (!strcasecmp(argv[0], "repair")) {
3774 			set_bit(MD_RECOVERY_REQUESTED, &mddev->recovery);
3775 			set_bit(MD_RECOVERY_SYNC, &mddev->recovery);
3776 		} else
3777 			return -EINVAL;
3778 	}
3779 	if (mddev->ro == 2) {
3780 		/* A write to sync_action is enough to justify
3781 		 * canceling read-auto mode
3782 		 */
3783 		mddev->ro = 0;
3784 		if (!mddev->suspended)
3785 			md_wakeup_thread(mddev->sync_thread);
3786 	}
3787 	set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
3788 	if (!mddev->suspended)
3789 		md_wakeup_thread(mddev->thread);
3790 
3791 	return 0;
3792 }
3793 
3794 static int raid_iterate_devices(struct dm_target *ti,
3795 				iterate_devices_callout_fn fn, void *data)
3796 {
3797 	struct raid_set *rs = ti->private;
3798 	unsigned int i;
3799 	int r = 0;
3800 
3801 	for (i = 0; !r && i < rs->raid_disks; i++) {
3802 		if (rs->dev[i].data_dev) {
3803 			r = fn(ti, rs->dev[i].data_dev,
3804 			       0, /* No offset on data devs */
3805 			       rs->md.dev_sectors, data);
3806 		}
3807 	}
3808 
3809 	return r;
3810 }
3811 
3812 static void raid_io_hints(struct dm_target *ti, struct queue_limits *limits)
3813 {
3814 	struct raid_set *rs = ti->private;
3815 	unsigned int chunk_size_bytes = to_bytes(rs->md.chunk_sectors);
3816 
3817 	limits->io_min = chunk_size_bytes;
3818 	limits->io_opt = chunk_size_bytes * mddev_data_stripes(rs);
3819 }
3820 
3821 static void raid_presuspend(struct dm_target *ti)
3822 {
3823 	struct raid_set *rs = ti->private;
3824 	struct mddev *mddev = &rs->md;
3825 
3826 	/*
3827 	 * From now on, disallow raid_message() to change sync_thread until
3828 	 * resume, raid_postsuspend() is too late.
3829 	 */
3830 	set_bit(RT_FLAG_RS_FROZEN, &rs->runtime_flags);
3831 
3832 	if (!reshape_interrupted(mddev))
3833 		return;
3834 
3835 	/*
3836 	 * For raid456, if reshape is interrupted, IO across reshape position
3837 	 * will never make progress, while caller will wait for IO to be done.
3838 	 * Inform raid456 to handle those IO to prevent deadlock.
3839 	 */
3840 	if (mddev->pers && mddev->pers->prepare_suspend)
3841 		mddev->pers->prepare_suspend(mddev);
3842 }
3843 
3844 static void raid_presuspend_undo(struct dm_target *ti)
3845 {
3846 	struct raid_set *rs = ti->private;
3847 
3848 	clear_bit(RT_FLAG_RS_FROZEN, &rs->runtime_flags);
3849 }
3850 
3851 static void raid_postsuspend(struct dm_target *ti)
3852 {
3853 	struct raid_set *rs = ti->private;
3854 
3855 	if (!test_and_set_bit(RT_FLAG_RS_SUSPENDED, &rs->runtime_flags)) {
3856 		/*
3857 		 * sync_thread must be stopped during suspend, and writes have
3858 		 * to be stopped before suspending to avoid deadlocks.
3859 		 */
3860 		md_stop_writes(&rs->md);
3861 		mddev_suspend(&rs->md, false);
3862 	}
3863 }
3864 
3865 static void attempt_restore_of_faulty_devices(struct raid_set *rs)
3866 {
3867 	int i;
3868 	uint64_t cleared_failed_devices[DISKS_ARRAY_ELEMS];
3869 	unsigned long flags;
3870 	bool cleared = false;
3871 	struct dm_raid_superblock *sb;
3872 	struct mddev *mddev = &rs->md;
3873 	struct md_rdev *r;
3874 
3875 	/* RAID personalities have to provide hot add/remove methods or we need to bail out. */
3876 	if (!mddev->pers || !mddev->pers->hot_add_disk || !mddev->pers->hot_remove_disk)
3877 		return;
3878 
3879 	memset(cleared_failed_devices, 0, sizeof(cleared_failed_devices));
3880 
3881 	for (i = 0; i < rs->raid_disks; i++) {
3882 		r = &rs->dev[i].rdev;
3883 		/* HM FIXME: enhance journal device recovery processing */
3884 		if (test_bit(Journal, &r->flags))
3885 			continue;
3886 
3887 		if (test_bit(Faulty, &r->flags) &&
3888 		    r->meta_bdev && !read_disk_sb(r, r->sb_size, true)) {
3889 			DMINFO("Faulty %s device #%d has readable super block."
3890 			       "  Attempting to revive it.",
3891 			       rs->raid_type->name, i);
3892 
3893 			/*
3894 			 * Faulty bit may be set, but sometimes the array can
3895 			 * be suspended before the personalities can respond
3896 			 * by removing the device from the array (i.e. calling
3897 			 * 'hot_remove_disk').	If they haven't yet removed
3898 			 * the failed device, its 'raid_disk' number will be
3899 			 * '>= 0' - meaning we must call this function
3900 			 * ourselves.
3901 			 */
3902 			flags = r->flags;
3903 			clear_bit(In_sync, &r->flags); /* Mandatory for hot remove. */
3904 			if (r->raid_disk >= 0) {
3905 				if (mddev->pers->hot_remove_disk(mddev, r)) {
3906 					/* Failed to revive this device, try next */
3907 					r->flags = flags;
3908 					continue;
3909 				}
3910 			} else
3911 				r->raid_disk = r->saved_raid_disk = i;
3912 
3913 			clear_bit(Faulty, &r->flags);
3914 			clear_bit(WriteErrorSeen, &r->flags);
3915 
3916 			if (mddev->pers->hot_add_disk(mddev, r)) {
3917 				/* Failed to revive this device, try next */
3918 				r->raid_disk = r->saved_raid_disk = -1;
3919 				r->flags = flags;
3920 			} else {
3921 				clear_bit(In_sync, &r->flags);
3922 				r->recovery_offset = 0;
3923 				set_bit(i, (void *) cleared_failed_devices);
3924 				cleared = true;
3925 			}
3926 		}
3927 	}
3928 
3929 	/* If any failed devices could be cleared, update all sbs failed_devices bits */
3930 	if (cleared) {
3931 		uint64_t failed_devices[DISKS_ARRAY_ELEMS];
3932 
3933 		rdev_for_each(r, &rs->md) {
3934 			if (test_bit(Journal, &r->flags))
3935 				continue;
3936 
3937 			sb = page_address(r->sb_page);
3938 			sb_retrieve_failed_devices(sb, failed_devices);
3939 
3940 			for (i = 0; i < DISKS_ARRAY_ELEMS; i++)
3941 				failed_devices[i] &= ~cleared_failed_devices[i];
3942 
3943 			sb_update_failed_devices(sb, failed_devices);
3944 		}
3945 	}
3946 }
3947 
3948 static int __load_dirty_region_bitmap(struct raid_set *rs)
3949 {
3950 	int r = 0;
3951 
3952 	/* Try loading the bitmap unless "raid0", which does not have one */
3953 	if (!rs_is_raid0(rs) &&
3954 	    !test_and_set_bit(RT_FLAG_RS_BITMAP_LOADED, &rs->runtime_flags)) {
3955 		struct mddev *mddev = &rs->md;
3956 
3957 		r = mddev->bitmap_ops->load(mddev);
3958 		if (r)
3959 			DMERR("Failed to load bitmap");
3960 	}
3961 
3962 	return r;
3963 }
3964 
3965 /* Enforce updating all superblocks */
3966 static void rs_update_sbs(struct raid_set *rs)
3967 {
3968 	struct mddev *mddev = &rs->md;
3969 	int ro = mddev->ro;
3970 
3971 	set_bit(MD_SB_CHANGE_DEVS, &mddev->sb_flags);
3972 	mddev->ro = 0;
3973 	md_update_sb(mddev, 1);
3974 	mddev->ro = ro;
3975 }
3976 
3977 /*
3978  * Reshape changes raid algorithm of @rs to new one within personality
3979  * (e.g. raid6_zr -> raid6_nc), changes stripe size, adds/removes
3980  * disks from a raid set thus growing/shrinking it or resizes the set
3981  *
3982  * Call mddev_lock_nointr() before!
3983  */
3984 static int rs_start_reshape(struct raid_set *rs)
3985 {
3986 	int r;
3987 	struct mddev *mddev = &rs->md;
3988 	struct md_personality *pers = mddev->pers;
3989 
3990 	/* Don't allow the sync thread to work until the table gets reloaded. */
3991 	set_bit(MD_RECOVERY_WAIT, &mddev->recovery);
3992 
3993 	r = rs_setup_reshape(rs);
3994 	if (r)
3995 		return r;
3996 
3997 	/*
3998 	 * Check any reshape constraints enforced by the personalility
3999 	 *
4000 	 * May as well already kick the reshape off so that * pers->start_reshape() becomes optional.
4001 	 */
4002 	r = pers->check_reshape(mddev);
4003 	if (r) {
4004 		rs->ti->error = "pers->check_reshape() failed";
4005 		return r;
4006 	}
4007 
4008 	/*
4009 	 * Personality may not provide start reshape method in which
4010 	 * case check_reshape above has already covered everything
4011 	 */
4012 	if (pers->start_reshape) {
4013 		r = pers->start_reshape(mddev);
4014 		if (r) {
4015 			rs->ti->error = "pers->start_reshape() failed";
4016 			return r;
4017 		}
4018 	}
4019 
4020 	/*
4021 	 * Now reshape got set up, update superblocks to
4022 	 * reflect the fact so that a table reload will
4023 	 * access proper superblock content in the ctr.
4024 	 */
4025 	rs_update_sbs(rs);
4026 
4027 	return 0;
4028 }
4029 
4030 static int raid_preresume(struct dm_target *ti)
4031 {
4032 	int r;
4033 	struct raid_set *rs = ti->private;
4034 	struct mddev *mddev = &rs->md;
4035 
4036 	/* This is a resume after a suspend of the set -> it's already started. */
4037 	if (test_and_set_bit(RT_FLAG_RS_PRERESUMED, &rs->runtime_flags))
4038 		return 0;
4039 
4040 	/* If different and no explicit grow request, expose MD array size as of superblock. */
4041 	if (!test_bit(RT_FLAG_RS_GROW, &rs->runtime_flags) &&
4042 	    rs->array_sectors != mddev->array_sectors)
4043 		rs_set_capacity(rs);
4044 
4045 	/*
4046 	 * The superblocks need to be updated on disk if the
4047 	 * array is new or new devices got added (thus zeroed
4048 	 * out by userspace) or __load_dirty_region_bitmap
4049 	 * will overwrite them in core with old data or fail.
4050 	 */
4051 	if (test_bit(RT_FLAG_UPDATE_SBS, &rs->runtime_flags))
4052 		rs_update_sbs(rs);
4053 
4054 	/* Load the bitmap from disk unless raid0 */
4055 	r = __load_dirty_region_bitmap(rs);
4056 	if (r)
4057 		return r;
4058 
4059 	/* We are extending the raid set size, adjust mddev/md_rdev sizes and set capacity. */
4060 	if (test_bit(RT_FLAG_RS_GROW, &rs->runtime_flags)) {
4061 		mddev->array_sectors = rs->array_sectors;
4062 		mddev->dev_sectors = rs->dev_sectors;
4063 		rs_set_rdev_sectors(rs);
4064 		rs_set_capacity(rs);
4065 	}
4066 
4067 	/* Resize bitmap to adjust to changed region size (aka MD bitmap chunksize) or grown device size */
4068 	if (test_bit(RT_FLAG_RS_BITMAP_LOADED, &rs->runtime_flags) && mddev->bitmap &&
4069 	    (test_bit(RT_FLAG_RS_GROW, &rs->runtime_flags) ||
4070 	     (rs->requested_bitmap_chunk_sectors &&
4071 	       mddev->bitmap_info.chunksize != to_bytes(rs->requested_bitmap_chunk_sectors)))) {
4072 		int chunksize = to_bytes(rs->requested_bitmap_chunk_sectors) ?: mddev->bitmap_info.chunksize;
4073 
4074 		r = mddev->bitmap_ops->resize(mddev, mddev->dev_sectors,
4075 					      chunksize, false);
4076 		if (r)
4077 			DMERR("Failed to resize bitmap");
4078 	}
4079 
4080 	/* Check for any resize/reshape on @rs and adjust/initiate */
4081 	if (mddev->recovery_cp && mddev->recovery_cp < MaxSector) {
4082 		set_bit(MD_RECOVERY_REQUESTED, &mddev->recovery);
4083 		mddev->resync_min = mddev->recovery_cp;
4084 		if (test_bit(RT_FLAG_RS_GROW, &rs->runtime_flags))
4085 			mddev->resync_max_sectors = mddev->dev_sectors;
4086 	}
4087 
4088 	/* Check for any reshape request unless new raid set */
4089 	if (test_bit(RT_FLAG_RESHAPE_RS, &rs->runtime_flags)) {
4090 		/* Initiate a reshape. */
4091 		rs_set_rdev_sectors(rs);
4092 		mddev_lock_nointr(mddev);
4093 		r = rs_start_reshape(rs);
4094 		mddev_unlock(mddev);
4095 		if (r)
4096 			DMWARN("Failed to check/start reshape, continuing without change");
4097 		r = 0;
4098 	}
4099 
4100 	return r;
4101 }
4102 
4103 static void raid_resume(struct dm_target *ti)
4104 {
4105 	struct raid_set *rs = ti->private;
4106 	struct mddev *mddev = &rs->md;
4107 
4108 	if (test_and_set_bit(RT_FLAG_RS_RESUMED, &rs->runtime_flags)) {
4109 		/*
4110 		 * A secondary resume while the device is active.
4111 		 * Take this opportunity to check whether any failed
4112 		 * devices are reachable again.
4113 		 */
4114 		mddev_lock_nointr(mddev);
4115 		attempt_restore_of_faulty_devices(rs);
4116 		mddev_unlock(mddev);
4117 	}
4118 
4119 	if (test_and_clear_bit(RT_FLAG_RS_SUSPENDED, &rs->runtime_flags)) {
4120 		/* Only reduce raid set size before running a disk removing reshape. */
4121 		if (mddev->delta_disks < 0)
4122 			rs_set_capacity(rs);
4123 
4124 		mddev_lock_nointr(mddev);
4125 		WARN_ON_ONCE(!test_bit(MD_RECOVERY_FROZEN, &mddev->recovery));
4126 		WARN_ON_ONCE(rcu_dereference_protected(mddev->sync_thread,
4127 						       lockdep_is_held(&mddev->reconfig_mutex)));
4128 		clear_bit(RT_FLAG_RS_FROZEN, &rs->runtime_flags);
4129 		mddev->ro = 0;
4130 		mddev->in_sync = 0;
4131 		md_unfrozen_sync_thread(mddev);
4132 		mddev_unlock_and_resume(mddev);
4133 	}
4134 }
4135 
4136 static struct target_type raid_target = {
4137 	.name = "raid",
4138 	.version = {1, 15, 1},
4139 	.module = THIS_MODULE,
4140 	.ctr = raid_ctr,
4141 	.dtr = raid_dtr,
4142 	.map = raid_map,
4143 	.status = raid_status,
4144 	.message = raid_message,
4145 	.iterate_devices = raid_iterate_devices,
4146 	.io_hints = raid_io_hints,
4147 	.presuspend = raid_presuspend,
4148 	.presuspend_undo = raid_presuspend_undo,
4149 	.postsuspend = raid_postsuspend,
4150 	.preresume = raid_preresume,
4151 	.resume = raid_resume,
4152 };
4153 module_dm(raid);
4154 
4155 module_param(devices_handle_discard_safely, bool, 0644);
4156 MODULE_PARM_DESC(devices_handle_discard_safely,
4157 		 "Set to Y if all devices in each array reliably return zeroes on reads from discarded regions");
4158 
4159 MODULE_DESCRIPTION(DM_NAME " raid0/1/10/4/5/6 target");
4160 MODULE_ALIAS("dm-raid0");
4161 MODULE_ALIAS("dm-raid1");
4162 MODULE_ALIAS("dm-raid10");
4163 MODULE_ALIAS("dm-raid4");
4164 MODULE_ALIAS("dm-raid5");
4165 MODULE_ALIAS("dm-raid6");
4166 MODULE_AUTHOR("Neil Brown <dm-devel@lists.linux.dev>");
4167 MODULE_AUTHOR("Heinz Mauelshagen <dm-devel@lists.linux.dev>");
4168 MODULE_LICENSE("GPL");
4169