xref: /openbmc/linux/drivers/md/dm-raid.c (revision 2a598d0b)
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 
18 #include <linux/device-mapper.h>
19 
20 #define DM_MSG_PREFIX "raid"
21 #define	MAX_RAID_DEVICES	253 /* md-raid kernel limit */
22 
23 /*
24  * Minimum sectors of free reshape space per raid device
25  */
26 #define	MIN_FREE_RESHAPE_SPACE to_sector(4*4096)
27 
28 /*
29  * Minimum journal space 4 MiB in sectors.
30  */
31 #define	MIN_RAID456_JOURNAL_SPACE (4*2048)
32 
33 static bool devices_handle_discard_safely;
34 
35 /*
36  * The following flags are used by dm-raid to set up the array state.
37  * They must be cleared before md_run is called.
38  */
39 #define FirstUse 10		/* rdev flag */
40 
41 struct raid_dev {
42 	/*
43 	 * Two DM devices, one to hold metadata and one to hold the
44 	 * actual data/parity.	The reason for this is to not confuse
45 	 * ti->len and give more flexibility in altering size and
46 	 * characteristics.
47 	 *
48 	 * While it is possible for this device to be associated
49 	 * with a different physical device than the data_dev, it
50 	 * is intended for it to be the same.
51 	 *    |--------- Physical Device ---------|
52 	 *    |- meta_dev -|------ data_dev ------|
53 	 */
54 	struct dm_dev *meta_dev;
55 	struct dm_dev *data_dev;
56 	struct md_rdev rdev;
57 };
58 
59 /*
60  * Bits for establishing rs->ctr_flags
61  *
62  * 1 = no flag value
63  * 2 = flag with value
64  */
65 #define __CTR_FLAG_SYNC			0  /* 1 */ /* Not with raid0! */
66 #define __CTR_FLAG_NOSYNC		1  /* 1 */ /* Not with raid0! */
67 #define __CTR_FLAG_REBUILD		2  /* 2 */ /* Not with raid0! */
68 #define __CTR_FLAG_DAEMON_SLEEP		3  /* 2 */ /* Not with raid0! */
69 #define __CTR_FLAG_MIN_RECOVERY_RATE	4  /* 2 */ /* Not with raid0! */
70 #define __CTR_FLAG_MAX_RECOVERY_RATE	5  /* 2 */ /* Not with raid0! */
71 #define __CTR_FLAG_MAX_WRITE_BEHIND	6  /* 2 */ /* Only with raid1! */
72 #define __CTR_FLAG_WRITE_MOSTLY		7  /* 2 */ /* Only with raid1! */
73 #define __CTR_FLAG_STRIPE_CACHE		8  /* 2 */ /* Only with raid4/5/6! */
74 #define __CTR_FLAG_REGION_SIZE		9  /* 2 */ /* Not with raid0! */
75 #define __CTR_FLAG_RAID10_COPIES	10 /* 2 */ /* Only with raid10 */
76 #define __CTR_FLAG_RAID10_FORMAT	11 /* 2 */ /* Only with raid10 */
77 /* New for v1.9.0 */
78 #define __CTR_FLAG_DELTA_DISKS		12 /* 2 */ /* Only with reshapable raid1/4/5/6/10! */
79 #define __CTR_FLAG_DATA_OFFSET		13 /* 2 */ /* Only with reshapable raid4/5/6/10! */
80 #define __CTR_FLAG_RAID10_USE_NEAR_SETS 14 /* 2 */ /* Only with raid10! */
81 
82 /* New for v1.10.0 */
83 #define __CTR_FLAG_JOURNAL_DEV		15 /* 2 */ /* Only with raid4/5/6 (journal device)! */
84 
85 /* New for v1.11.1 */
86 #define __CTR_FLAG_JOURNAL_MODE		16 /* 2 */ /* Only with raid4/5/6 (journal mode)! */
87 
88 /*
89  * Flags for rs->ctr_flags field.
90  */
91 #define CTR_FLAG_SYNC			(1 << __CTR_FLAG_SYNC)
92 #define CTR_FLAG_NOSYNC			(1 << __CTR_FLAG_NOSYNC)
93 #define CTR_FLAG_REBUILD		(1 << __CTR_FLAG_REBUILD)
94 #define CTR_FLAG_DAEMON_SLEEP		(1 << __CTR_FLAG_DAEMON_SLEEP)
95 #define CTR_FLAG_MIN_RECOVERY_RATE	(1 << __CTR_FLAG_MIN_RECOVERY_RATE)
96 #define CTR_FLAG_MAX_RECOVERY_RATE	(1 << __CTR_FLAG_MAX_RECOVERY_RATE)
97 #define CTR_FLAG_MAX_WRITE_BEHIND	(1 << __CTR_FLAG_MAX_WRITE_BEHIND)
98 #define CTR_FLAG_WRITE_MOSTLY		(1 << __CTR_FLAG_WRITE_MOSTLY)
99 #define CTR_FLAG_STRIPE_CACHE		(1 << __CTR_FLAG_STRIPE_CACHE)
100 #define CTR_FLAG_REGION_SIZE		(1 << __CTR_FLAG_REGION_SIZE)
101 #define CTR_FLAG_RAID10_COPIES		(1 << __CTR_FLAG_RAID10_COPIES)
102 #define CTR_FLAG_RAID10_FORMAT		(1 << __CTR_FLAG_RAID10_FORMAT)
103 #define CTR_FLAG_DELTA_DISKS		(1 << __CTR_FLAG_DELTA_DISKS)
104 #define CTR_FLAG_DATA_OFFSET		(1 << __CTR_FLAG_DATA_OFFSET)
105 #define CTR_FLAG_RAID10_USE_NEAR_SETS	(1 << __CTR_FLAG_RAID10_USE_NEAR_SETS)
106 #define CTR_FLAG_JOURNAL_DEV		(1 << __CTR_FLAG_JOURNAL_DEV)
107 #define CTR_FLAG_JOURNAL_MODE		(1 << __CTR_FLAG_JOURNAL_MODE)
108 
109 /*
110  * Definitions of various constructor flags to
111  * be used in checks of valid / invalid flags
112  * per raid level.
113  */
114 /* Define all any sync flags */
115 #define	CTR_FLAGS_ANY_SYNC		(CTR_FLAG_SYNC | CTR_FLAG_NOSYNC)
116 
117 /* Define flags for options without argument (e.g. 'nosync') */
118 #define	CTR_FLAG_OPTIONS_NO_ARGS	(CTR_FLAGS_ANY_SYNC | \
119 					 CTR_FLAG_RAID10_USE_NEAR_SETS)
120 
121 /* Define flags for options with one argument (e.g. 'delta_disks +2') */
122 #define CTR_FLAG_OPTIONS_ONE_ARG (CTR_FLAG_REBUILD | \
123 				  CTR_FLAG_WRITE_MOSTLY | \
124 				  CTR_FLAG_DAEMON_SLEEP | \
125 				  CTR_FLAG_MIN_RECOVERY_RATE | \
126 				  CTR_FLAG_MAX_RECOVERY_RATE | \
127 				  CTR_FLAG_MAX_WRITE_BEHIND | \
128 				  CTR_FLAG_STRIPE_CACHE | \
129 				  CTR_FLAG_REGION_SIZE | \
130 				  CTR_FLAG_RAID10_COPIES | \
131 				  CTR_FLAG_RAID10_FORMAT | \
132 				  CTR_FLAG_DELTA_DISKS | \
133 				  CTR_FLAG_DATA_OFFSET | \
134 				  CTR_FLAG_JOURNAL_DEV | \
135 				  CTR_FLAG_JOURNAL_MODE)
136 
137 /* Valid options definitions per raid level... */
138 
139 /* "raid0" does only accept data offset */
140 #define RAID0_VALID_FLAGS	(CTR_FLAG_DATA_OFFSET)
141 
142 /* "raid1" does not accept stripe cache, data offset, delta_disks or any raid10 options */
143 #define RAID1_VALID_FLAGS	(CTR_FLAGS_ANY_SYNC | \
144 				 CTR_FLAG_REBUILD | \
145 				 CTR_FLAG_WRITE_MOSTLY | \
146 				 CTR_FLAG_DAEMON_SLEEP | \
147 				 CTR_FLAG_MIN_RECOVERY_RATE | \
148 				 CTR_FLAG_MAX_RECOVERY_RATE | \
149 				 CTR_FLAG_MAX_WRITE_BEHIND | \
150 				 CTR_FLAG_REGION_SIZE | \
151 				 CTR_FLAG_DELTA_DISKS | \
152 				 CTR_FLAG_DATA_OFFSET)
153 
154 /* "raid10" does not accept any raid1 or stripe cache options */
155 #define RAID10_VALID_FLAGS	(CTR_FLAGS_ANY_SYNC | \
156 				 CTR_FLAG_REBUILD | \
157 				 CTR_FLAG_DAEMON_SLEEP | \
158 				 CTR_FLAG_MIN_RECOVERY_RATE | \
159 				 CTR_FLAG_MAX_RECOVERY_RATE | \
160 				 CTR_FLAG_REGION_SIZE | \
161 				 CTR_FLAG_RAID10_COPIES | \
162 				 CTR_FLAG_RAID10_FORMAT | \
163 				 CTR_FLAG_DELTA_DISKS | \
164 				 CTR_FLAG_DATA_OFFSET | \
165 				 CTR_FLAG_RAID10_USE_NEAR_SETS)
166 
167 /*
168  * "raid4/5/6" do not accept any raid1 or raid10 specific options
169  *
170  * "raid6" does not accept "nosync", because it is not guaranteed
171  * that both parity and q-syndrome are being written properly with
172  * any writes
173  */
174 #define RAID45_VALID_FLAGS	(CTR_FLAGS_ANY_SYNC | \
175 				 CTR_FLAG_REBUILD | \
176 				 CTR_FLAG_DAEMON_SLEEP | \
177 				 CTR_FLAG_MIN_RECOVERY_RATE | \
178 				 CTR_FLAG_MAX_RECOVERY_RATE | \
179 				 CTR_FLAG_STRIPE_CACHE | \
180 				 CTR_FLAG_REGION_SIZE | \
181 				 CTR_FLAG_DELTA_DISKS | \
182 				 CTR_FLAG_DATA_OFFSET | \
183 				 CTR_FLAG_JOURNAL_DEV | \
184 				 CTR_FLAG_JOURNAL_MODE)
185 
186 #define RAID6_VALID_FLAGS	(CTR_FLAG_SYNC | \
187 				 CTR_FLAG_REBUILD | \
188 				 CTR_FLAG_DAEMON_SLEEP | \
189 				 CTR_FLAG_MIN_RECOVERY_RATE | \
190 				 CTR_FLAG_MAX_RECOVERY_RATE | \
191 				 CTR_FLAG_STRIPE_CACHE | \
192 				 CTR_FLAG_REGION_SIZE | \
193 				 CTR_FLAG_DELTA_DISKS | \
194 				 CTR_FLAG_DATA_OFFSET | \
195 				 CTR_FLAG_JOURNAL_DEV | \
196 				 CTR_FLAG_JOURNAL_MODE)
197 /* ...valid options definitions per raid level */
198 
199 /*
200  * Flags for rs->runtime_flags field
201  * (RT_FLAG prefix meaning "runtime flag")
202  *
203  * These are all internal and used to define runtime state,
204  * e.g. to prevent another resume from preresume processing
205  * the raid set all over again.
206  */
207 #define RT_FLAG_RS_PRERESUMED		0
208 #define RT_FLAG_RS_RESUMED		1
209 #define RT_FLAG_RS_BITMAP_LOADED	2
210 #define RT_FLAG_UPDATE_SBS		3
211 #define RT_FLAG_RESHAPE_RS		4
212 #define RT_FLAG_RS_SUSPENDED		5
213 #define RT_FLAG_RS_IN_SYNC		6
214 #define RT_FLAG_RS_RESYNCING		7
215 #define RT_FLAG_RS_GROW			8
216 
217 /* Array elements of 64 bit needed for rebuild/failed disk bits */
218 #define DISKS_ARRAY_ELEMS ((MAX_RAID_DEVICES + (sizeof(uint64_t) * 8 - 1)) / sizeof(uint64_t) / 8)
219 
220 /*
221  * raid set level, layout and chunk sectors backup/restore
222  */
223 struct rs_layout {
224 	int new_level;
225 	int new_layout;
226 	int new_chunk_sectors;
227 };
228 
229 struct raid_set {
230 	struct dm_target *ti;
231 
232 	uint32_t stripe_cache_entries;
233 	unsigned long ctr_flags;
234 	unsigned long runtime_flags;
235 
236 	uint64_t rebuild_disks[DISKS_ARRAY_ELEMS];
237 
238 	int raid_disks;
239 	int delta_disks;
240 	int data_offset;
241 	int raid10_copies;
242 	int requested_bitmap_chunk_sectors;
243 
244 	struct mddev md;
245 	struct raid_type *raid_type;
246 
247 	sector_t array_sectors;
248 	sector_t dev_sectors;
249 
250 	/* Optional raid4/5/6 journal device */
251 	struct journal_dev {
252 		struct dm_dev *dev;
253 		struct md_rdev rdev;
254 		int mode;
255 	} journal_dev;
256 
257 	struct raid_dev dev[];
258 };
259 
260 static void rs_config_backup(struct raid_set *rs, struct rs_layout *l)
261 {
262 	struct mddev *mddev = &rs->md;
263 
264 	l->new_level = mddev->new_level;
265 	l->new_layout = mddev->new_layout;
266 	l->new_chunk_sectors = mddev->new_chunk_sectors;
267 }
268 
269 static void rs_config_restore(struct raid_set *rs, struct rs_layout *l)
270 {
271 	struct mddev *mddev = &rs->md;
272 
273 	mddev->new_level = l->new_level;
274 	mddev->new_layout = l->new_layout;
275 	mddev->new_chunk_sectors = l->new_chunk_sectors;
276 }
277 
278 /* raid10 algorithms (i.e. formats) */
279 #define	ALGORITHM_RAID10_DEFAULT	0
280 #define	ALGORITHM_RAID10_NEAR		1
281 #define	ALGORITHM_RAID10_OFFSET		2
282 #define	ALGORITHM_RAID10_FAR		3
283 
284 /* Supported raid types and properties. */
285 static struct raid_type {
286 	const char *name;		/* RAID algorithm. */
287 	const char *descr;		/* Descriptor text for logging. */
288 	const unsigned int parity_devs;	/* # of parity devices. */
289 	const unsigned int minimal_devs;/* minimal # of devices in set. */
290 	const unsigned int level;	/* RAID level. */
291 	const unsigned int algorithm;	/* RAID algorithm. */
292 } raid_types[] = {
293 	{"raid0",	  "raid0 (striping)",			    0, 2, 0,  0 /* NONE */},
294 	{"raid1",	  "raid1 (mirroring)",			    0, 2, 1,  0 /* NONE */},
295 	{"raid10_far",	  "raid10 far (striped mirrors)",	    0, 2, 10, ALGORITHM_RAID10_FAR},
296 	{"raid10_offset", "raid10 offset (striped mirrors)",	    0, 2, 10, ALGORITHM_RAID10_OFFSET},
297 	{"raid10_near",	  "raid10 near (striped mirrors)",	    0, 2, 10, ALGORITHM_RAID10_NEAR},
298 	{"raid10",	  "raid10 (striped mirrors)",		    0, 2, 10, ALGORITHM_RAID10_DEFAULT},
299 	{"raid4",	  "raid4 (dedicated first parity disk)",    1, 2, 5,  ALGORITHM_PARITY_0}, /* raid4 layout = raid5_0 */
300 	{"raid5_n",	  "raid5 (dedicated last parity disk)",	    1, 2, 5,  ALGORITHM_PARITY_N},
301 	{"raid5_ls",	  "raid5 (left symmetric)",		    1, 2, 5,  ALGORITHM_LEFT_SYMMETRIC},
302 	{"raid5_rs",	  "raid5 (right symmetric)",		    1, 2, 5,  ALGORITHM_RIGHT_SYMMETRIC},
303 	{"raid5_la",	  "raid5 (left asymmetric)",		    1, 2, 5,  ALGORITHM_LEFT_ASYMMETRIC},
304 	{"raid5_ra",	  "raid5 (right asymmetric)",		    1, 2, 5,  ALGORITHM_RIGHT_ASYMMETRIC},
305 	{"raid6_zr",	  "raid6 (zero restart)",		    2, 4, 6,  ALGORITHM_ROTATING_ZERO_RESTART},
306 	{"raid6_nr",	  "raid6 (N restart)",			    2, 4, 6,  ALGORITHM_ROTATING_N_RESTART},
307 	{"raid6_nc",	  "raid6 (N continue)",			    2, 4, 6,  ALGORITHM_ROTATING_N_CONTINUE},
308 	{"raid6_n_6",	  "raid6 (dedicated parity/Q n/6)",	    2, 4, 6,  ALGORITHM_PARITY_N_6},
309 	{"raid6_ls_6",	  "raid6 (left symmetric dedicated Q 6)",   2, 4, 6,  ALGORITHM_LEFT_SYMMETRIC_6},
310 	{"raid6_rs_6",	  "raid6 (right symmetric dedicated Q 6)",  2, 4, 6,  ALGORITHM_RIGHT_SYMMETRIC_6},
311 	{"raid6_la_6",	  "raid6 (left asymmetric dedicated Q 6)",  2, 4, 6,  ALGORITHM_LEFT_ASYMMETRIC_6},
312 	{"raid6_ra_6",	  "raid6 (right asymmetric dedicated Q 6)", 2, 4, 6,  ALGORITHM_RIGHT_ASYMMETRIC_6}
313 };
314 
315 /* True, if @v is in inclusive range [@min, @max] */
316 static bool __within_range(long v, long min, long max)
317 {
318 	return v >= min && v <= max;
319 }
320 
321 /* All table line arguments are defined here */
322 static struct arg_name_flag {
323 	const unsigned long flag;
324 	const char *name;
325 } __arg_name_flags[] = {
326 	{ CTR_FLAG_SYNC, "sync"},
327 	{ CTR_FLAG_NOSYNC, "nosync"},
328 	{ CTR_FLAG_REBUILD, "rebuild"},
329 	{ CTR_FLAG_DAEMON_SLEEP, "daemon_sleep"},
330 	{ CTR_FLAG_MIN_RECOVERY_RATE, "min_recovery_rate"},
331 	{ CTR_FLAG_MAX_RECOVERY_RATE, "max_recovery_rate"},
332 	{ CTR_FLAG_MAX_WRITE_BEHIND, "max_write_behind"},
333 	{ CTR_FLAG_WRITE_MOSTLY, "write_mostly"},
334 	{ CTR_FLAG_STRIPE_CACHE, "stripe_cache"},
335 	{ CTR_FLAG_REGION_SIZE, "region_size"},
336 	{ CTR_FLAG_RAID10_COPIES, "raid10_copies"},
337 	{ CTR_FLAG_RAID10_FORMAT, "raid10_format"},
338 	{ CTR_FLAG_DATA_OFFSET, "data_offset"},
339 	{ CTR_FLAG_DELTA_DISKS, "delta_disks"},
340 	{ CTR_FLAG_RAID10_USE_NEAR_SETS, "raid10_use_near_sets"},
341 	{ CTR_FLAG_JOURNAL_DEV, "journal_dev" },
342 	{ CTR_FLAG_JOURNAL_MODE, "journal_mode" },
343 };
344 
345 /* Return argument name string for given @flag */
346 static const char *dm_raid_arg_name_by_flag(const uint32_t flag)
347 {
348 	if (hweight32(flag) == 1) {
349 		struct arg_name_flag *anf = __arg_name_flags + ARRAY_SIZE(__arg_name_flags);
350 
351 		while (anf-- > __arg_name_flags)
352 			if (flag & anf->flag)
353 				return anf->name;
354 
355 	} else
356 		DMERR("%s called with more than one flag!", __func__);
357 
358 	return NULL;
359 }
360 
361 /* Define correlation of raid456 journal cache modes and dm-raid target line parameters */
362 static struct {
363 	const int mode;
364 	const char *param;
365 } _raid456_journal_mode[] = {
366 	{ R5C_JOURNAL_MODE_WRITE_THROUGH, "writethrough" },
367 	{ R5C_JOURNAL_MODE_WRITE_BACK,    "writeback" }
368 };
369 
370 /* Return MD raid4/5/6 journal mode for dm @journal_mode one */
371 static int dm_raid_journal_mode_to_md(const char *mode)
372 {
373 	int m = ARRAY_SIZE(_raid456_journal_mode);
374 
375 	while (m--)
376 		if (!strcasecmp(mode, _raid456_journal_mode[m].param))
377 			return _raid456_journal_mode[m].mode;
378 
379 	return -EINVAL;
380 }
381 
382 /* Return dm-raid raid4/5/6 journal mode string for @mode */
383 static const char *md_journal_mode_to_dm_raid(const int mode)
384 {
385 	int m = ARRAY_SIZE(_raid456_journal_mode);
386 
387 	while (m--)
388 		if (mode == _raid456_journal_mode[m].mode)
389 			return _raid456_journal_mode[m].param;
390 
391 	return "unknown";
392 }
393 
394 /*
395  * Bool helpers to test for various raid levels of a raid set.
396  * It's level as reported by the superblock rather than
397  * the requested raid_type passed to the constructor.
398  */
399 /* Return true, if raid set in @rs is raid0 */
400 static bool rs_is_raid0(struct raid_set *rs)
401 {
402 	return !rs->md.level;
403 }
404 
405 /* Return true, if raid set in @rs is raid1 */
406 static bool rs_is_raid1(struct raid_set *rs)
407 {
408 	return rs->md.level == 1;
409 }
410 
411 /* Return true, if raid set in @rs is raid10 */
412 static bool rs_is_raid10(struct raid_set *rs)
413 {
414 	return rs->md.level == 10;
415 }
416 
417 /* Return true, if raid set in @rs is level 6 */
418 static bool rs_is_raid6(struct raid_set *rs)
419 {
420 	return rs->md.level == 6;
421 }
422 
423 /* Return true, if raid set in @rs is level 4, 5 or 6 */
424 static bool rs_is_raid456(struct raid_set *rs)
425 {
426 	return __within_range(rs->md.level, 4, 6);
427 }
428 
429 /* Return true, if raid set in @rs is reshapable */
430 static bool __is_raid10_far(int layout);
431 static bool rs_is_reshapable(struct raid_set *rs)
432 {
433 	return rs_is_raid456(rs) ||
434 	       (rs_is_raid10(rs) && !__is_raid10_far(rs->md.new_layout));
435 }
436 
437 /* Return true, if raid set in @rs is recovering */
438 static bool rs_is_recovering(struct raid_set *rs)
439 {
440 	return rs->md.recovery_cp < rs->md.dev_sectors;
441 }
442 
443 /* Return true, if raid set in @rs is reshaping */
444 static bool rs_is_reshaping(struct raid_set *rs)
445 {
446 	return rs->md.reshape_position != MaxSector;
447 }
448 
449 /*
450  * bool helpers to test for various raid levels of a raid type @rt
451  */
452 
453 /* Return true, if raid type in @rt is raid0 */
454 static bool rt_is_raid0(struct raid_type *rt)
455 {
456 	return !rt->level;
457 }
458 
459 /* Return true, if raid type in @rt is raid1 */
460 static bool rt_is_raid1(struct raid_type *rt)
461 {
462 	return rt->level == 1;
463 }
464 
465 /* Return true, if raid type in @rt is raid10 */
466 static bool rt_is_raid10(struct raid_type *rt)
467 {
468 	return rt->level == 10;
469 }
470 
471 /* Return true, if raid type in @rt is raid4/5 */
472 static bool rt_is_raid45(struct raid_type *rt)
473 {
474 	return __within_range(rt->level, 4, 5);
475 }
476 
477 /* Return true, if raid type in @rt is raid6 */
478 static bool rt_is_raid6(struct raid_type *rt)
479 {
480 	return rt->level == 6;
481 }
482 
483 /* Return true, if raid type in @rt is raid4/5/6 */
484 static bool rt_is_raid456(struct raid_type *rt)
485 {
486 	return __within_range(rt->level, 4, 6);
487 }
488 /* END: raid level bools */
489 
490 /* Return valid ctr flags for the raid level of @rs */
491 static unsigned long __valid_flags(struct raid_set *rs)
492 {
493 	if (rt_is_raid0(rs->raid_type))
494 		return RAID0_VALID_FLAGS;
495 	else if (rt_is_raid1(rs->raid_type))
496 		return RAID1_VALID_FLAGS;
497 	else if (rt_is_raid10(rs->raid_type))
498 		return RAID10_VALID_FLAGS;
499 	else if (rt_is_raid45(rs->raid_type))
500 		return RAID45_VALID_FLAGS;
501 	else if (rt_is_raid6(rs->raid_type))
502 		return RAID6_VALID_FLAGS;
503 
504 	return 0;
505 }
506 
507 /*
508  * Check for valid flags set on @rs
509  *
510  * Has to be called after parsing of the ctr flags!
511  */
512 static int rs_check_for_valid_flags(struct raid_set *rs)
513 {
514 	if (rs->ctr_flags & ~__valid_flags(rs)) {
515 		rs->ti->error = "Invalid flags combination";
516 		return -EINVAL;
517 	}
518 
519 	return 0;
520 }
521 
522 /* MD raid10 bit definitions and helpers */
523 #define RAID10_OFFSET			(1 << 16) /* stripes with data copies area adjacent on devices */
524 #define RAID10_BROCKEN_USE_FAR_SETS	(1 << 17) /* Broken in raid10.c: use sets instead of whole stripe rotation */
525 #define RAID10_USE_FAR_SETS		(1 << 18) /* Use sets instead of whole stripe rotation */
526 #define RAID10_FAR_COPIES_SHIFT		8	  /* raid10 # far copies shift (2nd byte of layout) */
527 
528 /* Return md raid10 near copies for @layout */
529 static unsigned int __raid10_near_copies(int layout)
530 {
531 	return layout & 0xFF;
532 }
533 
534 /* Return md raid10 far copies for @layout */
535 static unsigned int __raid10_far_copies(int layout)
536 {
537 	return __raid10_near_copies(layout >> RAID10_FAR_COPIES_SHIFT);
538 }
539 
540 /* Return true if md raid10 offset for @layout */
541 static bool __is_raid10_offset(int layout)
542 {
543 	return !!(layout & RAID10_OFFSET);
544 }
545 
546 /* Return true if md raid10 near for @layout */
547 static bool __is_raid10_near(int layout)
548 {
549 	return !__is_raid10_offset(layout) && __raid10_near_copies(layout) > 1;
550 }
551 
552 /* Return true if md raid10 far for @layout */
553 static bool __is_raid10_far(int layout)
554 {
555 	return !__is_raid10_offset(layout) && __raid10_far_copies(layout) > 1;
556 }
557 
558 /* Return md raid10 layout string for @layout */
559 static const char *raid10_md_layout_to_format(int layout)
560 {
561 	/*
562 	 * Bit 16 stands for "offset"
563 	 * (i.e. adjacent stripes hold copies)
564 	 *
565 	 * Refer to MD's raid10.c for details
566 	 */
567 	if (__is_raid10_offset(layout))
568 		return "offset";
569 
570 	if (__raid10_near_copies(layout) > 1)
571 		return "near";
572 
573 	if (__raid10_far_copies(layout) > 1)
574 		return "far";
575 
576 	return "unknown";
577 }
578 
579 /* Return md raid10 algorithm for @name */
580 static int raid10_name_to_format(const char *name)
581 {
582 	if (!strcasecmp(name, "near"))
583 		return ALGORITHM_RAID10_NEAR;
584 	else if (!strcasecmp(name, "offset"))
585 		return ALGORITHM_RAID10_OFFSET;
586 	else if (!strcasecmp(name, "far"))
587 		return ALGORITHM_RAID10_FAR;
588 
589 	return -EINVAL;
590 }
591 
592 /* Return md raid10 copies for @layout */
593 static unsigned int raid10_md_layout_to_copies(int layout)
594 {
595 	return max(__raid10_near_copies(layout), __raid10_far_copies(layout));
596 }
597 
598 /* Return md raid10 format id for @format string */
599 static int raid10_format_to_md_layout(struct raid_set *rs,
600 				      unsigned int algorithm,
601 				      unsigned int copies)
602 {
603 	unsigned int n = 1, f = 1, r = 0;
604 
605 	/*
606 	 * MD resilienece flaw:
607 	 *
608 	 * enabling use_far_sets for far/offset formats causes copies
609 	 * to be colocated on the same devs together with their origins!
610 	 *
611 	 * -> disable it for now in the definition above
612 	 */
613 	if (algorithm == ALGORITHM_RAID10_DEFAULT ||
614 	    algorithm == ALGORITHM_RAID10_NEAR)
615 		n = copies;
616 
617 	else if (algorithm == ALGORITHM_RAID10_OFFSET) {
618 		f = copies;
619 		r = RAID10_OFFSET;
620 		if (!test_bit(__CTR_FLAG_RAID10_USE_NEAR_SETS, &rs->ctr_flags))
621 			r |= RAID10_USE_FAR_SETS;
622 
623 	} else if (algorithm == ALGORITHM_RAID10_FAR) {
624 		f = copies;
625 		if (!test_bit(__CTR_FLAG_RAID10_USE_NEAR_SETS, &rs->ctr_flags))
626 			r |= RAID10_USE_FAR_SETS;
627 
628 	} else
629 		return -EINVAL;
630 
631 	return r | (f << RAID10_FAR_COPIES_SHIFT) | n;
632 }
633 /* END: MD raid10 bit definitions and helpers */
634 
635 /* Check for any of the raid10 algorithms */
636 static bool __got_raid10(struct raid_type *rtp, const int layout)
637 {
638 	if (rtp->level == 10) {
639 		switch (rtp->algorithm) {
640 		case ALGORITHM_RAID10_DEFAULT:
641 		case ALGORITHM_RAID10_NEAR:
642 			return __is_raid10_near(layout);
643 		case ALGORITHM_RAID10_OFFSET:
644 			return __is_raid10_offset(layout);
645 		case ALGORITHM_RAID10_FAR:
646 			return __is_raid10_far(layout);
647 		default:
648 			break;
649 		}
650 	}
651 
652 	return false;
653 }
654 
655 /* Return raid_type for @name */
656 static struct raid_type *get_raid_type(const char *name)
657 {
658 	struct raid_type *rtp = raid_types + ARRAY_SIZE(raid_types);
659 
660 	while (rtp-- > raid_types)
661 		if (!strcasecmp(rtp->name, name))
662 			return rtp;
663 
664 	return NULL;
665 }
666 
667 /* Return raid_type for @name based derived from @level and @layout */
668 static struct raid_type *get_raid_type_by_ll(const int level, const int layout)
669 {
670 	struct raid_type *rtp = raid_types + ARRAY_SIZE(raid_types);
671 
672 	while (rtp-- > raid_types) {
673 		/* RAID10 special checks based on @layout flags/properties */
674 		if (rtp->level == level &&
675 		    (__got_raid10(rtp, layout) || rtp->algorithm == layout))
676 			return rtp;
677 	}
678 
679 	return NULL;
680 }
681 
682 /* Adjust rdev sectors */
683 static void rs_set_rdev_sectors(struct raid_set *rs)
684 {
685 	struct mddev *mddev = &rs->md;
686 	struct md_rdev *rdev;
687 
688 	/*
689 	 * raid10 sets rdev->sector to the device size, which
690 	 * is unintended in case of out-of-place reshaping
691 	 */
692 	rdev_for_each(rdev, mddev)
693 		if (!test_bit(Journal, &rdev->flags))
694 			rdev->sectors = mddev->dev_sectors;
695 }
696 
697 /*
698  * Change bdev capacity of @rs in case of a disk add/remove reshape
699  */
700 static void rs_set_capacity(struct raid_set *rs)
701 {
702 	struct gendisk *gendisk = dm_disk(dm_table_get_md(rs->ti->table));
703 
704 	set_capacity_and_notify(gendisk, rs->md.array_sectors);
705 }
706 
707 /*
708  * Set the mddev properties in @rs to the current
709  * ones retrieved from the freshest superblock
710  */
711 static void rs_set_cur(struct raid_set *rs)
712 {
713 	struct mddev *mddev = &rs->md;
714 
715 	mddev->new_level = mddev->level;
716 	mddev->new_layout = mddev->layout;
717 	mddev->new_chunk_sectors = mddev->chunk_sectors;
718 }
719 
720 /*
721  * Set the mddev properties in @rs to the new
722  * ones requested by the ctr
723  */
724 static void rs_set_new(struct raid_set *rs)
725 {
726 	struct mddev *mddev = &rs->md;
727 
728 	mddev->level = mddev->new_level;
729 	mddev->layout = mddev->new_layout;
730 	mddev->chunk_sectors = mddev->new_chunk_sectors;
731 	mddev->raid_disks = rs->raid_disks;
732 	mddev->delta_disks = 0;
733 }
734 
735 static struct raid_set *raid_set_alloc(struct dm_target *ti, struct raid_type *raid_type,
736 				       unsigned int raid_devs)
737 {
738 	unsigned int i;
739 	struct raid_set *rs;
740 
741 	if (raid_devs <= raid_type->parity_devs) {
742 		ti->error = "Insufficient number of devices";
743 		return ERR_PTR(-EINVAL);
744 	}
745 
746 	rs = kzalloc(struct_size(rs, dev, raid_devs), GFP_KERNEL);
747 	if (!rs) {
748 		ti->error = "Cannot allocate raid context";
749 		return ERR_PTR(-ENOMEM);
750 	}
751 
752 	mddev_init(&rs->md);
753 
754 	rs->raid_disks = raid_devs;
755 	rs->delta_disks = 0;
756 
757 	rs->ti = ti;
758 	rs->raid_type = raid_type;
759 	rs->stripe_cache_entries = 256;
760 	rs->md.raid_disks = raid_devs;
761 	rs->md.level = raid_type->level;
762 	rs->md.new_level = rs->md.level;
763 	rs->md.layout = raid_type->algorithm;
764 	rs->md.new_layout = rs->md.layout;
765 	rs->md.delta_disks = 0;
766 	rs->md.recovery_cp = MaxSector;
767 
768 	for (i = 0; i < raid_devs; i++)
769 		md_rdev_init(&rs->dev[i].rdev);
770 
771 	/*
772 	 * Remaining items to be initialized by further RAID params:
773 	 *  rs->md.persistent
774 	 *  rs->md.external
775 	 *  rs->md.chunk_sectors
776 	 *  rs->md.new_chunk_sectors
777 	 *  rs->md.dev_sectors
778 	 */
779 
780 	return rs;
781 }
782 
783 /* Free all @rs allocations */
784 static void raid_set_free(struct raid_set *rs)
785 {
786 	int i;
787 
788 	if (rs->journal_dev.dev) {
789 		md_rdev_clear(&rs->journal_dev.rdev);
790 		dm_put_device(rs->ti, rs->journal_dev.dev);
791 	}
792 
793 	for (i = 0; i < rs->raid_disks; i++) {
794 		if (rs->dev[i].meta_dev)
795 			dm_put_device(rs->ti, rs->dev[i].meta_dev);
796 		md_rdev_clear(&rs->dev[i].rdev);
797 		if (rs->dev[i].data_dev)
798 			dm_put_device(rs->ti, rs->dev[i].data_dev);
799 	}
800 
801 	kfree(rs);
802 }
803 
804 /*
805  * For every device we have two words
806  *  <meta_dev>: meta device name or '-' if missing
807  *  <data_dev>: data device name or '-' if missing
808  *
809  * The following are permitted:
810  *    - -
811  *    - <data_dev>
812  *    <meta_dev> <data_dev>
813  *
814  * The following is not allowed:
815  *    <meta_dev> -
816  *
817  * This code parses those words.  If there is a failure,
818  * the caller must use raid_set_free() to unwind the operations.
819  */
820 static int parse_dev_params(struct raid_set *rs, struct dm_arg_set *as)
821 {
822 	int i;
823 	int rebuild = 0;
824 	int metadata_available = 0;
825 	int r = 0;
826 	const char *arg;
827 
828 	/* Put off the number of raid devices argument to get to dev pairs */
829 	arg = dm_shift_arg(as);
830 	if (!arg)
831 		return -EINVAL;
832 
833 	for (i = 0; i < rs->raid_disks; i++) {
834 		rs->dev[i].rdev.raid_disk = i;
835 
836 		rs->dev[i].meta_dev = NULL;
837 		rs->dev[i].data_dev = NULL;
838 
839 		/*
840 		 * There are no offsets initially.
841 		 * Out of place reshape will set them accordingly.
842 		 */
843 		rs->dev[i].rdev.data_offset = 0;
844 		rs->dev[i].rdev.new_data_offset = 0;
845 		rs->dev[i].rdev.mddev = &rs->md;
846 
847 		arg = dm_shift_arg(as);
848 		if (!arg)
849 			return -EINVAL;
850 
851 		if (strcmp(arg, "-")) {
852 			r = dm_get_device(rs->ti, arg, dm_table_get_mode(rs->ti->table),
853 					  &rs->dev[i].meta_dev);
854 			if (r) {
855 				rs->ti->error = "RAID metadata device lookup failure";
856 				return r;
857 			}
858 
859 			rs->dev[i].rdev.sb_page = alloc_page(GFP_KERNEL);
860 			if (!rs->dev[i].rdev.sb_page) {
861 				rs->ti->error = "Failed to allocate superblock page";
862 				return -ENOMEM;
863 			}
864 		}
865 
866 		arg = dm_shift_arg(as);
867 		if (!arg)
868 			return -EINVAL;
869 
870 		if (!strcmp(arg, "-")) {
871 			if (!test_bit(In_sync, &rs->dev[i].rdev.flags) &&
872 			    (!rs->dev[i].rdev.recovery_offset)) {
873 				rs->ti->error = "Drive designated for rebuild not specified";
874 				return -EINVAL;
875 			}
876 
877 			if (rs->dev[i].meta_dev) {
878 				rs->ti->error = "No data device supplied with metadata device";
879 				return -EINVAL;
880 			}
881 
882 			continue;
883 		}
884 
885 		r = dm_get_device(rs->ti, arg, dm_table_get_mode(rs->ti->table),
886 				  &rs->dev[i].data_dev);
887 		if (r) {
888 			rs->ti->error = "RAID device lookup failure";
889 			return r;
890 		}
891 
892 		if (rs->dev[i].meta_dev) {
893 			metadata_available = 1;
894 			rs->dev[i].rdev.meta_bdev = rs->dev[i].meta_dev->bdev;
895 		}
896 		rs->dev[i].rdev.bdev = rs->dev[i].data_dev->bdev;
897 		list_add_tail(&rs->dev[i].rdev.same_set, &rs->md.disks);
898 		if (!test_bit(In_sync, &rs->dev[i].rdev.flags))
899 			rebuild++;
900 	}
901 
902 	if (rs->journal_dev.dev)
903 		list_add_tail(&rs->journal_dev.rdev.same_set, &rs->md.disks);
904 
905 	if (metadata_available) {
906 		rs->md.external = 0;
907 		rs->md.persistent = 1;
908 		rs->md.major_version = 2;
909 	} else if (rebuild && !rs->md.recovery_cp) {
910 		/*
911 		 * Without metadata, we will not be able to tell if the array
912 		 * is in-sync or not - we must assume it is not.  Therefore,
913 		 * it is impossible to rebuild a drive.
914 		 *
915 		 * Even if there is metadata, the on-disk information may
916 		 * indicate that the array is not in-sync and it will then
917 		 * fail at that time.
918 		 *
919 		 * User could specify 'nosync' option if desperate.
920 		 */
921 		rs->ti->error = "Unable to rebuild drive while array is not in-sync";
922 		return -EINVAL;
923 	}
924 
925 	return 0;
926 }
927 
928 /*
929  * validate_region_size
930  * @rs
931  * @region_size:  region size in sectors.  If 0, pick a size (4MiB default).
932  *
933  * Set rs->md.bitmap_info.chunksize (which really refers to 'region size').
934  * Ensure that (ti->len/region_size < 2^21) - required by MD bitmap.
935  *
936  * Returns: 0 on success, -EINVAL on failure.
937  */
938 static int validate_region_size(struct raid_set *rs, unsigned long region_size)
939 {
940 	unsigned long min_region_size = rs->ti->len / (1 << 21);
941 
942 	if (rs_is_raid0(rs))
943 		return 0;
944 
945 	if (!region_size) {
946 		/*
947 		 * Choose a reasonable default.	 All figures in sectors.
948 		 */
949 		if (min_region_size > (1 << 13)) {
950 			/* If not a power of 2, make it the next power of 2 */
951 			region_size = roundup_pow_of_two(min_region_size);
952 			DMINFO("Choosing default region size of %lu sectors",
953 			       region_size);
954 		} else {
955 			DMINFO("Choosing default region size of 4MiB");
956 			region_size = 1 << 13; /* sectors */
957 		}
958 	} else {
959 		/*
960 		 * Validate user-supplied value.
961 		 */
962 		if (region_size > rs->ti->len) {
963 			rs->ti->error = "Supplied region size is too large";
964 			return -EINVAL;
965 		}
966 
967 		if (region_size < min_region_size) {
968 			DMERR("Supplied region_size (%lu sectors) below minimum (%lu)",
969 			      region_size, min_region_size);
970 			rs->ti->error = "Supplied region size is too small";
971 			return -EINVAL;
972 		}
973 
974 		if (!is_power_of_2(region_size)) {
975 			rs->ti->error = "Region size is not a power of 2";
976 			return -EINVAL;
977 		}
978 
979 		if (region_size < rs->md.chunk_sectors) {
980 			rs->ti->error = "Region size is smaller than the chunk size";
981 			return -EINVAL;
982 		}
983 	}
984 
985 	/*
986 	 * Convert sectors to bytes.
987 	 */
988 	rs->md.bitmap_info.chunksize = to_bytes(region_size);
989 
990 	return 0;
991 }
992 
993 /*
994  * validate_raid_redundancy
995  * @rs
996  *
997  * Determine if there are enough devices in the array that haven't
998  * failed (or are being rebuilt) to form a usable array.
999  *
1000  * Returns: 0 on success, -EINVAL on failure.
1001  */
1002 static int validate_raid_redundancy(struct raid_set *rs)
1003 {
1004 	unsigned int i, rebuild_cnt = 0;
1005 	unsigned int rebuilds_per_group = 0, copies, raid_disks;
1006 	unsigned int group_size, last_group_start;
1007 
1008 	for (i = 0; i < rs->raid_disks; i++)
1009 		if (!test_bit(FirstUse, &rs->dev[i].rdev.flags) &&
1010 		    ((!test_bit(In_sync, &rs->dev[i].rdev.flags) ||
1011 		      !rs->dev[i].rdev.sb_page)))
1012 			rebuild_cnt++;
1013 
1014 	switch (rs->md.level) {
1015 	case 0:
1016 		break;
1017 	case 1:
1018 		if (rebuild_cnt >= rs->md.raid_disks)
1019 			goto too_many;
1020 		break;
1021 	case 4:
1022 	case 5:
1023 	case 6:
1024 		if (rebuild_cnt > rs->raid_type->parity_devs)
1025 			goto too_many;
1026 		break;
1027 	case 10:
1028 		copies = raid10_md_layout_to_copies(rs->md.new_layout);
1029 		if (copies < 2) {
1030 			DMERR("Bogus raid10 data copies < 2!");
1031 			return -EINVAL;
1032 		}
1033 
1034 		if (rebuild_cnt < copies)
1035 			break;
1036 
1037 		/*
1038 		 * It is possible to have a higher rebuild count for RAID10,
1039 		 * as long as the failed devices occur in different mirror
1040 		 * groups (i.e. different stripes).
1041 		 *
1042 		 * When checking "near" format, make sure no adjacent devices
1043 		 * have failed beyond what can be handled.  In addition to the
1044 		 * simple case where the number of devices is a multiple of the
1045 		 * number of copies, we must also handle cases where the number
1046 		 * of devices is not a multiple of the number of copies.
1047 		 * E.g.	   dev1 dev2 dev3 dev4 dev5
1048 		 *	    A	 A    B	   B	C
1049 		 *	    C	 D    D	   E	E
1050 		 */
1051 		raid_disks = min(rs->raid_disks, rs->md.raid_disks);
1052 		if (__is_raid10_near(rs->md.new_layout)) {
1053 			for (i = 0; i < raid_disks; i++) {
1054 				if (!(i % copies))
1055 					rebuilds_per_group = 0;
1056 				if ((!rs->dev[i].rdev.sb_page ||
1057 				    !test_bit(In_sync, &rs->dev[i].rdev.flags)) &&
1058 				    (++rebuilds_per_group >= copies))
1059 					goto too_many;
1060 			}
1061 			break;
1062 		}
1063 
1064 		/*
1065 		 * When checking "far" and "offset" formats, we need to ensure
1066 		 * that the device that holds its copy is not also dead or
1067 		 * being rebuilt.  (Note that "far" and "offset" formats only
1068 		 * support two copies right now.  These formats also only ever
1069 		 * use the 'use_far_sets' variant.)
1070 		 *
1071 		 * This check is somewhat complicated by the need to account
1072 		 * for arrays that are not a multiple of (far) copies.	This
1073 		 * results in the need to treat the last (potentially larger)
1074 		 * set differently.
1075 		 */
1076 		group_size = (raid_disks / copies);
1077 		last_group_start = (raid_disks / group_size) - 1;
1078 		last_group_start *= group_size;
1079 		for (i = 0; i < raid_disks; i++) {
1080 			if (!(i % copies) && !(i > last_group_start))
1081 				rebuilds_per_group = 0;
1082 			if ((!rs->dev[i].rdev.sb_page ||
1083 			     !test_bit(In_sync, &rs->dev[i].rdev.flags)) &&
1084 			    (++rebuilds_per_group >= copies))
1085 				goto too_many;
1086 		}
1087 		break;
1088 	default:
1089 		if (rebuild_cnt)
1090 			return -EINVAL;
1091 	}
1092 
1093 	return 0;
1094 
1095 too_many:
1096 	return -EINVAL;
1097 }
1098 
1099 /*
1100  * Possible arguments are...
1101  *	<chunk_size> [optional_args]
1102  *
1103  * Argument definitions
1104  *    <chunk_size>			The number of sectors per disk that
1105  *					will form the "stripe"
1106  *    [[no]sync]			Force or prevent recovery of the
1107  *					entire array
1108  *    [rebuild <idx>]			Rebuild the drive indicated by the index
1109  *    [daemon_sleep <ms>]		Time between bitmap daemon work to
1110  *					clear bits
1111  *    [min_recovery_rate <kB/sec/disk>]	Throttle RAID initialization
1112  *    [max_recovery_rate <kB/sec/disk>]	Throttle RAID initialization
1113  *    [write_mostly <idx>]		Indicate a write mostly drive via index
1114  *    [max_write_behind <sectors>]	See '-write-behind=' (man mdadm)
1115  *    [stripe_cache <sectors>]		Stripe cache size for higher RAIDs
1116  *    [region_size <sectors>]		Defines granularity of bitmap
1117  *    [journal_dev <dev>]		raid4/5/6 journaling deviice
1118  *					(i.e. write hole closing log)
1119  *
1120  * RAID10-only options:
1121  *    [raid10_copies <# copies>]	Number of copies.  (Default: 2)
1122  *    [raid10_format <near|far|offset>] Layout algorithm.  (Default: near)
1123  */
1124 static int parse_raid_params(struct raid_set *rs, struct dm_arg_set *as,
1125 			     unsigned int num_raid_params)
1126 {
1127 	int value, raid10_format = ALGORITHM_RAID10_DEFAULT;
1128 	unsigned int raid10_copies = 2;
1129 	unsigned int i, write_mostly = 0;
1130 	unsigned int region_size = 0;
1131 	sector_t max_io_len;
1132 	const char *arg, *key;
1133 	struct raid_dev *rd;
1134 	struct raid_type *rt = rs->raid_type;
1135 
1136 	arg = dm_shift_arg(as);
1137 	num_raid_params--; /* Account for chunk_size argument */
1138 
1139 	if (kstrtoint(arg, 10, &value) < 0) {
1140 		rs->ti->error = "Bad numerical argument given for chunk_size";
1141 		return -EINVAL;
1142 	}
1143 
1144 	/*
1145 	 * First, parse the in-order required arguments
1146 	 * "chunk_size" is the only argument of this type.
1147 	 */
1148 	if (rt_is_raid1(rt)) {
1149 		if (value)
1150 			DMERR("Ignoring chunk size parameter for RAID 1");
1151 		value = 0;
1152 	} else if (!is_power_of_2(value)) {
1153 		rs->ti->error = "Chunk size must be a power of 2";
1154 		return -EINVAL;
1155 	} else if (value < 8) {
1156 		rs->ti->error = "Chunk size value is too small";
1157 		return -EINVAL;
1158 	}
1159 
1160 	rs->md.new_chunk_sectors = rs->md.chunk_sectors = value;
1161 
1162 	/*
1163 	 * We set each individual device as In_sync with a completed
1164 	 * 'recovery_offset'.  If there has been a device failure or
1165 	 * replacement then one of the following cases applies:
1166 	 *
1167 	 *   1) User specifies 'rebuild'.
1168 	 *	- Device is reset when param is read.
1169 	 *   2) A new device is supplied.
1170 	 *	- No matching superblock found, resets device.
1171 	 *   3) Device failure was transient and returns on reload.
1172 	 *	- Failure noticed, resets device for bitmap replay.
1173 	 *   4) Device hadn't completed recovery after previous failure.
1174 	 *	- Superblock is read and overrides recovery_offset.
1175 	 *
1176 	 * What is found in the superblocks of the devices is always
1177 	 * authoritative, unless 'rebuild' or '[no]sync' was specified.
1178 	 */
1179 	for (i = 0; i < rs->raid_disks; i++) {
1180 		set_bit(In_sync, &rs->dev[i].rdev.flags);
1181 		rs->dev[i].rdev.recovery_offset = MaxSector;
1182 	}
1183 
1184 	/*
1185 	 * Second, parse the unordered optional arguments
1186 	 */
1187 	for (i = 0; i < num_raid_params; i++) {
1188 		key = dm_shift_arg(as);
1189 		if (!key) {
1190 			rs->ti->error = "Not enough raid parameters given";
1191 			return -EINVAL;
1192 		}
1193 
1194 		if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_NOSYNC))) {
1195 			if (test_and_set_bit(__CTR_FLAG_NOSYNC, &rs->ctr_flags)) {
1196 				rs->ti->error = "Only one 'nosync' argument allowed";
1197 				return -EINVAL;
1198 			}
1199 			continue;
1200 		}
1201 		if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_SYNC))) {
1202 			if (test_and_set_bit(__CTR_FLAG_SYNC, &rs->ctr_flags)) {
1203 				rs->ti->error = "Only one 'sync' argument allowed";
1204 				return -EINVAL;
1205 			}
1206 			continue;
1207 		}
1208 		if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_RAID10_USE_NEAR_SETS))) {
1209 			if (test_and_set_bit(__CTR_FLAG_RAID10_USE_NEAR_SETS, &rs->ctr_flags)) {
1210 				rs->ti->error = "Only one 'raid10_use_new_sets' argument allowed";
1211 				return -EINVAL;
1212 			}
1213 			continue;
1214 		}
1215 
1216 		arg = dm_shift_arg(as);
1217 		i++; /* Account for the argument pairs */
1218 		if (!arg) {
1219 			rs->ti->error = "Wrong number of raid parameters given";
1220 			return -EINVAL;
1221 		}
1222 
1223 		/*
1224 		 * Parameters that take a string value are checked here.
1225 		 */
1226 		/* "raid10_format {near|offset|far} */
1227 		if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_RAID10_FORMAT))) {
1228 			if (test_and_set_bit(__CTR_FLAG_RAID10_FORMAT, &rs->ctr_flags)) {
1229 				rs->ti->error = "Only one 'raid10_format' argument pair allowed";
1230 				return -EINVAL;
1231 			}
1232 			if (!rt_is_raid10(rt)) {
1233 				rs->ti->error = "'raid10_format' is an invalid parameter for this RAID type";
1234 				return -EINVAL;
1235 			}
1236 			raid10_format = raid10_name_to_format(arg);
1237 			if (raid10_format < 0) {
1238 				rs->ti->error = "Invalid 'raid10_format' value given";
1239 				return raid10_format;
1240 			}
1241 			continue;
1242 		}
1243 
1244 		/* "journal_dev <dev>" */
1245 		if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_JOURNAL_DEV))) {
1246 			int r;
1247 			struct md_rdev *jdev;
1248 
1249 			if (test_and_set_bit(__CTR_FLAG_JOURNAL_DEV, &rs->ctr_flags)) {
1250 				rs->ti->error = "Only one raid4/5/6 set journaling device allowed";
1251 				return -EINVAL;
1252 			}
1253 			if (!rt_is_raid456(rt)) {
1254 				rs->ti->error = "'journal_dev' is an invalid parameter for this RAID type";
1255 				return -EINVAL;
1256 			}
1257 			r = dm_get_device(rs->ti, arg, dm_table_get_mode(rs->ti->table),
1258 					  &rs->journal_dev.dev);
1259 			if (r) {
1260 				rs->ti->error = "raid4/5/6 journal device lookup failure";
1261 				return r;
1262 			}
1263 			jdev = &rs->journal_dev.rdev;
1264 			md_rdev_init(jdev);
1265 			jdev->mddev = &rs->md;
1266 			jdev->bdev = rs->journal_dev.dev->bdev;
1267 			jdev->sectors = bdev_nr_sectors(jdev->bdev);
1268 			if (jdev->sectors < MIN_RAID456_JOURNAL_SPACE) {
1269 				rs->ti->error = "No space for raid4/5/6 journal";
1270 				return -ENOSPC;
1271 			}
1272 			rs->journal_dev.mode = R5C_JOURNAL_MODE_WRITE_THROUGH;
1273 			set_bit(Journal, &jdev->flags);
1274 			continue;
1275 		}
1276 
1277 		/* "journal_mode <mode>" ("journal_dev" mandatory!) */
1278 		if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_JOURNAL_MODE))) {
1279 			int r;
1280 
1281 			if (!test_bit(__CTR_FLAG_JOURNAL_DEV, &rs->ctr_flags)) {
1282 				rs->ti->error = "raid4/5/6 'journal_mode' is invalid without 'journal_dev'";
1283 				return -EINVAL;
1284 			}
1285 			if (test_and_set_bit(__CTR_FLAG_JOURNAL_MODE, &rs->ctr_flags)) {
1286 				rs->ti->error = "Only one raid4/5/6 'journal_mode' argument allowed";
1287 				return -EINVAL;
1288 			}
1289 			r = dm_raid_journal_mode_to_md(arg);
1290 			if (r < 0) {
1291 				rs->ti->error = "Invalid 'journal_mode' argument";
1292 				return r;
1293 			}
1294 			rs->journal_dev.mode = r;
1295 			continue;
1296 		}
1297 
1298 		/*
1299 		 * Parameters with number values from here on.
1300 		 */
1301 		if (kstrtoint(arg, 10, &value) < 0) {
1302 			rs->ti->error = "Bad numerical argument given in raid params";
1303 			return -EINVAL;
1304 		}
1305 
1306 		if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_REBUILD))) {
1307 			/*
1308 			 * "rebuild" is being passed in by userspace to provide
1309 			 * indexes of replaced devices and to set up additional
1310 			 * devices on raid level takeover.
1311 			 */
1312 			if (!__within_range(value, 0, rs->raid_disks - 1)) {
1313 				rs->ti->error = "Invalid rebuild index given";
1314 				return -EINVAL;
1315 			}
1316 
1317 			if (test_and_set_bit(value, (void *) rs->rebuild_disks)) {
1318 				rs->ti->error = "rebuild for this index already given";
1319 				return -EINVAL;
1320 			}
1321 
1322 			rd = rs->dev + value;
1323 			clear_bit(In_sync, &rd->rdev.flags);
1324 			clear_bit(Faulty, &rd->rdev.flags);
1325 			rd->rdev.recovery_offset = 0;
1326 			set_bit(__CTR_FLAG_REBUILD, &rs->ctr_flags);
1327 		} else if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_WRITE_MOSTLY))) {
1328 			if (!rt_is_raid1(rt)) {
1329 				rs->ti->error = "write_mostly option is only valid for RAID1";
1330 				return -EINVAL;
1331 			}
1332 
1333 			if (!__within_range(value, 0, rs->md.raid_disks - 1)) {
1334 				rs->ti->error = "Invalid write_mostly index given";
1335 				return -EINVAL;
1336 			}
1337 
1338 			write_mostly++;
1339 			set_bit(WriteMostly, &rs->dev[value].rdev.flags);
1340 			set_bit(__CTR_FLAG_WRITE_MOSTLY, &rs->ctr_flags);
1341 		} else if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_MAX_WRITE_BEHIND))) {
1342 			if (!rt_is_raid1(rt)) {
1343 				rs->ti->error = "max_write_behind option is only valid for RAID1";
1344 				return -EINVAL;
1345 			}
1346 
1347 			if (test_and_set_bit(__CTR_FLAG_MAX_WRITE_BEHIND, &rs->ctr_flags)) {
1348 				rs->ti->error = "Only one max_write_behind argument pair allowed";
1349 				return -EINVAL;
1350 			}
1351 
1352 			/*
1353 			 * In device-mapper, we specify things in sectors, but
1354 			 * MD records this value in kB
1355 			 */
1356 			if (value < 0 || value / 2 > COUNTER_MAX) {
1357 				rs->ti->error = "Max write-behind limit out of range";
1358 				return -EINVAL;
1359 			}
1360 
1361 			rs->md.bitmap_info.max_write_behind = value / 2;
1362 		} else if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_DAEMON_SLEEP))) {
1363 			if (test_and_set_bit(__CTR_FLAG_DAEMON_SLEEP, &rs->ctr_flags)) {
1364 				rs->ti->error = "Only one daemon_sleep argument pair allowed";
1365 				return -EINVAL;
1366 			}
1367 			if (value < 0) {
1368 				rs->ti->error = "daemon sleep period out of range";
1369 				return -EINVAL;
1370 			}
1371 			rs->md.bitmap_info.daemon_sleep = value;
1372 		} else if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_DATA_OFFSET))) {
1373 			/* Userspace passes new data_offset after having extended the data image LV */
1374 			if (test_and_set_bit(__CTR_FLAG_DATA_OFFSET, &rs->ctr_flags)) {
1375 				rs->ti->error = "Only one data_offset argument pair allowed";
1376 				return -EINVAL;
1377 			}
1378 			/* Ensure sensible data offset */
1379 			if (value < 0 ||
1380 			    (value && (value < MIN_FREE_RESHAPE_SPACE || value % to_sector(PAGE_SIZE)))) {
1381 				rs->ti->error = "Bogus data_offset value";
1382 				return -EINVAL;
1383 			}
1384 			rs->data_offset = value;
1385 		} else if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_DELTA_DISKS))) {
1386 			/* Define the +/-# of disks to add to/remove from the given raid set */
1387 			if (test_and_set_bit(__CTR_FLAG_DELTA_DISKS, &rs->ctr_flags)) {
1388 				rs->ti->error = "Only one delta_disks argument pair allowed";
1389 				return -EINVAL;
1390 			}
1391 			/* Ensure MAX_RAID_DEVICES and raid type minimal_devs! */
1392 			if (!__within_range(abs(value), 1, MAX_RAID_DEVICES - rt->minimal_devs)) {
1393 				rs->ti->error = "Too many delta_disk requested";
1394 				return -EINVAL;
1395 			}
1396 
1397 			rs->delta_disks = value;
1398 		} else if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_STRIPE_CACHE))) {
1399 			if (test_and_set_bit(__CTR_FLAG_STRIPE_CACHE, &rs->ctr_flags)) {
1400 				rs->ti->error = "Only one stripe_cache argument pair allowed";
1401 				return -EINVAL;
1402 			}
1403 
1404 			if (!rt_is_raid456(rt)) {
1405 				rs->ti->error = "Inappropriate argument: stripe_cache";
1406 				return -EINVAL;
1407 			}
1408 
1409 			if (value < 0) {
1410 				rs->ti->error = "Bogus stripe cache entries value";
1411 				return -EINVAL;
1412 			}
1413 			rs->stripe_cache_entries = value;
1414 		} else if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_MIN_RECOVERY_RATE))) {
1415 			if (test_and_set_bit(__CTR_FLAG_MIN_RECOVERY_RATE, &rs->ctr_flags)) {
1416 				rs->ti->error = "Only one min_recovery_rate argument pair allowed";
1417 				return -EINVAL;
1418 			}
1419 
1420 			if (value < 0) {
1421 				rs->ti->error = "min_recovery_rate out of range";
1422 				return -EINVAL;
1423 			}
1424 			rs->md.sync_speed_min = value;
1425 		} else if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_MAX_RECOVERY_RATE))) {
1426 			if (test_and_set_bit(__CTR_FLAG_MAX_RECOVERY_RATE, &rs->ctr_flags)) {
1427 				rs->ti->error = "Only one max_recovery_rate argument pair allowed";
1428 				return -EINVAL;
1429 			}
1430 
1431 			if (value < 0) {
1432 				rs->ti->error = "max_recovery_rate out of range";
1433 				return -EINVAL;
1434 			}
1435 			rs->md.sync_speed_max = value;
1436 		} else if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_REGION_SIZE))) {
1437 			if (test_and_set_bit(__CTR_FLAG_REGION_SIZE, &rs->ctr_flags)) {
1438 				rs->ti->error = "Only one region_size argument pair allowed";
1439 				return -EINVAL;
1440 			}
1441 
1442 			region_size = value;
1443 			rs->requested_bitmap_chunk_sectors = value;
1444 		} else if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_RAID10_COPIES))) {
1445 			if (test_and_set_bit(__CTR_FLAG_RAID10_COPIES, &rs->ctr_flags)) {
1446 				rs->ti->error = "Only one raid10_copies argument pair allowed";
1447 				return -EINVAL;
1448 			}
1449 
1450 			if (!__within_range(value, 2, rs->md.raid_disks)) {
1451 				rs->ti->error = "Bad value for 'raid10_copies'";
1452 				return -EINVAL;
1453 			}
1454 
1455 			raid10_copies = value;
1456 		} else {
1457 			DMERR("Unable to parse RAID parameter: %s", key);
1458 			rs->ti->error = "Unable to parse RAID parameter";
1459 			return -EINVAL;
1460 		}
1461 	}
1462 
1463 	if (test_bit(__CTR_FLAG_SYNC, &rs->ctr_flags) &&
1464 	    test_bit(__CTR_FLAG_NOSYNC, &rs->ctr_flags)) {
1465 		rs->ti->error = "sync and nosync are mutually exclusive";
1466 		return -EINVAL;
1467 	}
1468 
1469 	if (test_bit(__CTR_FLAG_REBUILD, &rs->ctr_flags) &&
1470 	    (test_bit(__CTR_FLAG_SYNC, &rs->ctr_flags) ||
1471 	     test_bit(__CTR_FLAG_NOSYNC, &rs->ctr_flags))) {
1472 		rs->ti->error = "sync/nosync and rebuild are mutually exclusive";
1473 		return -EINVAL;
1474 	}
1475 
1476 	if (write_mostly >= rs->md.raid_disks) {
1477 		rs->ti->error = "Can't set all raid1 devices to write_mostly";
1478 		return -EINVAL;
1479 	}
1480 
1481 	if (rs->md.sync_speed_max &&
1482 	    rs->md.sync_speed_min > rs->md.sync_speed_max) {
1483 		rs->ti->error = "Bogus recovery rates";
1484 		return -EINVAL;
1485 	}
1486 
1487 	if (validate_region_size(rs, region_size))
1488 		return -EINVAL;
1489 
1490 	if (rs->md.chunk_sectors)
1491 		max_io_len = rs->md.chunk_sectors;
1492 	else
1493 		max_io_len = region_size;
1494 
1495 	if (dm_set_target_max_io_len(rs->ti, max_io_len))
1496 		return -EINVAL;
1497 
1498 	if (rt_is_raid10(rt)) {
1499 		if (raid10_copies > rs->md.raid_disks) {
1500 			rs->ti->error = "Not enough devices to satisfy specification";
1501 			return -EINVAL;
1502 		}
1503 
1504 		rs->md.new_layout = raid10_format_to_md_layout(rs, raid10_format, raid10_copies);
1505 		if (rs->md.new_layout < 0) {
1506 			rs->ti->error = "Error getting raid10 format";
1507 			return rs->md.new_layout;
1508 		}
1509 
1510 		rt = get_raid_type_by_ll(10, rs->md.new_layout);
1511 		if (!rt) {
1512 			rs->ti->error = "Failed to recognize new raid10 layout";
1513 			return -EINVAL;
1514 		}
1515 
1516 		if ((rt->algorithm == ALGORITHM_RAID10_DEFAULT ||
1517 		     rt->algorithm == ALGORITHM_RAID10_NEAR) &&
1518 		    test_bit(__CTR_FLAG_RAID10_USE_NEAR_SETS, &rs->ctr_flags)) {
1519 			rs->ti->error = "RAID10 format 'near' and 'raid10_use_near_sets' are incompatible";
1520 			return -EINVAL;
1521 		}
1522 	}
1523 
1524 	rs->raid10_copies = raid10_copies;
1525 
1526 	/* Assume there are no metadata devices until the drives are parsed */
1527 	rs->md.persistent = 0;
1528 	rs->md.external = 1;
1529 
1530 	/* Check, if any invalid ctr arguments have been passed in for the raid level */
1531 	return rs_check_for_valid_flags(rs);
1532 }
1533 
1534 /* Set raid4/5/6 cache size */
1535 static int rs_set_raid456_stripe_cache(struct raid_set *rs)
1536 {
1537 	int r;
1538 	struct r5conf *conf;
1539 	struct mddev *mddev = &rs->md;
1540 	uint32_t min_stripes = max(mddev->chunk_sectors, mddev->new_chunk_sectors) / 2;
1541 	uint32_t nr_stripes = rs->stripe_cache_entries;
1542 
1543 	if (!rt_is_raid456(rs->raid_type)) {
1544 		rs->ti->error = "Inappropriate raid level; cannot change stripe_cache size";
1545 		return -EINVAL;
1546 	}
1547 
1548 	if (nr_stripes < min_stripes) {
1549 		DMINFO("Adjusting requested %u stripe cache entries to %u to suit stripe size",
1550 		       nr_stripes, min_stripes);
1551 		nr_stripes = min_stripes;
1552 	}
1553 
1554 	conf = mddev->private;
1555 	if (!conf) {
1556 		rs->ti->error = "Cannot change stripe_cache size on inactive RAID set";
1557 		return -EINVAL;
1558 	}
1559 
1560 	/* Try setting number of stripes in raid456 stripe cache */
1561 	if (conf->min_nr_stripes != nr_stripes) {
1562 		r = raid5_set_cache_size(mddev, nr_stripes);
1563 		if (r) {
1564 			rs->ti->error = "Failed to set raid4/5/6 stripe cache size";
1565 			return r;
1566 		}
1567 
1568 		DMINFO("%u stripe cache entries", nr_stripes);
1569 	}
1570 
1571 	return 0;
1572 }
1573 
1574 /* Return # of data stripes as kept in mddev as of @rs (i.e. as of superblock) */
1575 static unsigned int mddev_data_stripes(struct raid_set *rs)
1576 {
1577 	return rs->md.raid_disks - rs->raid_type->parity_devs;
1578 }
1579 
1580 /* Return # of data stripes of @rs (i.e. as of ctr) */
1581 static unsigned int rs_data_stripes(struct raid_set *rs)
1582 {
1583 	return rs->raid_disks - rs->raid_type->parity_devs;
1584 }
1585 
1586 /*
1587  * Retrieve rdev->sectors from any valid raid device of @rs
1588  * to allow userpace to pass in arbitray "- -" device tupples.
1589  */
1590 static sector_t __rdev_sectors(struct raid_set *rs)
1591 {
1592 	int i;
1593 
1594 	for (i = 0; i < rs->raid_disks; i++) {
1595 		struct md_rdev *rdev = &rs->dev[i].rdev;
1596 
1597 		if (!test_bit(Journal, &rdev->flags) &&
1598 		    rdev->bdev && rdev->sectors)
1599 			return rdev->sectors;
1600 	}
1601 
1602 	return 0;
1603 }
1604 
1605 /* Check that calculated dev_sectors fits all component devices. */
1606 static int _check_data_dev_sectors(struct raid_set *rs)
1607 {
1608 	sector_t ds = ~0;
1609 	struct md_rdev *rdev;
1610 
1611 	rdev_for_each(rdev, &rs->md)
1612 		if (!test_bit(Journal, &rdev->flags) && rdev->bdev) {
1613 			ds = min(ds, bdev_nr_sectors(rdev->bdev));
1614 			if (ds < rs->md.dev_sectors) {
1615 				rs->ti->error = "Component device(s) too small";
1616 				return -EINVAL;
1617 			}
1618 		}
1619 
1620 	return 0;
1621 }
1622 
1623 /* Calculate the sectors per device and per array used for @rs */
1624 static int rs_set_dev_and_array_sectors(struct raid_set *rs, sector_t sectors, bool use_mddev)
1625 {
1626 	int delta_disks;
1627 	unsigned int data_stripes;
1628 	sector_t array_sectors = sectors, dev_sectors = sectors;
1629 	struct mddev *mddev = &rs->md;
1630 
1631 	if (use_mddev) {
1632 		delta_disks = mddev->delta_disks;
1633 		data_stripes = mddev_data_stripes(rs);
1634 	} else {
1635 		delta_disks = rs->delta_disks;
1636 		data_stripes = rs_data_stripes(rs);
1637 	}
1638 
1639 	/* Special raid1 case w/o delta_disks support (yet) */
1640 	if (rt_is_raid1(rs->raid_type))
1641 		;
1642 	else if (rt_is_raid10(rs->raid_type)) {
1643 		if (rs->raid10_copies < 2 ||
1644 		    delta_disks < 0) {
1645 			rs->ti->error = "Bogus raid10 data copies or delta disks";
1646 			return -EINVAL;
1647 		}
1648 
1649 		dev_sectors *= rs->raid10_copies;
1650 		if (sector_div(dev_sectors, data_stripes))
1651 			goto bad;
1652 
1653 		array_sectors = (data_stripes + delta_disks) * dev_sectors;
1654 		if (sector_div(array_sectors, rs->raid10_copies))
1655 			goto bad;
1656 
1657 	} else if (sector_div(dev_sectors, data_stripes))
1658 		goto bad;
1659 
1660 	else
1661 		/* Striped layouts */
1662 		array_sectors = (data_stripes + delta_disks) * dev_sectors;
1663 
1664 	mddev->array_sectors = array_sectors;
1665 	mddev->dev_sectors = dev_sectors;
1666 	rs_set_rdev_sectors(rs);
1667 
1668 	return _check_data_dev_sectors(rs);
1669 bad:
1670 	rs->ti->error = "Target length not divisible by number of data devices";
1671 	return -EINVAL;
1672 }
1673 
1674 /* Setup recovery on @rs */
1675 static void rs_setup_recovery(struct raid_set *rs, sector_t dev_sectors)
1676 {
1677 	/* raid0 does not recover */
1678 	if (rs_is_raid0(rs))
1679 		rs->md.recovery_cp = MaxSector;
1680 	/*
1681 	 * A raid6 set has to be recovered either
1682 	 * completely or for the grown part to
1683 	 * ensure proper parity and Q-Syndrome
1684 	 */
1685 	else if (rs_is_raid6(rs))
1686 		rs->md.recovery_cp = dev_sectors;
1687 	/*
1688 	 * Other raid set types may skip recovery
1689 	 * depending on the 'nosync' flag.
1690 	 */
1691 	else
1692 		rs->md.recovery_cp = test_bit(__CTR_FLAG_NOSYNC, &rs->ctr_flags)
1693 				     ? MaxSector : dev_sectors;
1694 }
1695 
1696 static void do_table_event(struct work_struct *ws)
1697 {
1698 	struct raid_set *rs = container_of(ws, struct raid_set, md.event_work);
1699 
1700 	smp_rmb(); /* Make sure we access most actual mddev properties */
1701 	if (!rs_is_reshaping(rs)) {
1702 		if (rs_is_raid10(rs))
1703 			rs_set_rdev_sectors(rs);
1704 		rs_set_capacity(rs);
1705 	}
1706 	dm_table_event(rs->ti->table);
1707 }
1708 
1709 /*
1710  * Make sure a valid takover (level switch) is being requested on @rs
1711  *
1712  * Conversions of raid sets from one MD personality to another
1713  * have to conform to restrictions which are enforced here.
1714  */
1715 static int rs_check_takeover(struct raid_set *rs)
1716 {
1717 	struct mddev *mddev = &rs->md;
1718 	unsigned int near_copies;
1719 
1720 	if (rs->md.degraded) {
1721 		rs->ti->error = "Can't takeover degraded raid set";
1722 		return -EPERM;
1723 	}
1724 
1725 	if (rs_is_reshaping(rs)) {
1726 		rs->ti->error = "Can't takeover reshaping raid set";
1727 		return -EPERM;
1728 	}
1729 
1730 	switch (mddev->level) {
1731 	case 0:
1732 		/* raid0 -> raid1/5 with one disk */
1733 		if ((mddev->new_level == 1 || mddev->new_level == 5) &&
1734 		    mddev->raid_disks == 1)
1735 			return 0;
1736 
1737 		/* raid0 -> raid10 */
1738 		if (mddev->new_level == 10 &&
1739 		    !(rs->raid_disks % mddev->raid_disks))
1740 			return 0;
1741 
1742 		/* raid0 with multiple disks -> raid4/5/6 */
1743 		if (__within_range(mddev->new_level, 4, 6) &&
1744 		    mddev->new_layout == ALGORITHM_PARITY_N &&
1745 		    mddev->raid_disks > 1)
1746 			return 0;
1747 
1748 		break;
1749 
1750 	case 10:
1751 		/* Can't takeover raid10_offset! */
1752 		if (__is_raid10_offset(mddev->layout))
1753 			break;
1754 
1755 		near_copies = __raid10_near_copies(mddev->layout);
1756 
1757 		/* raid10* -> raid0 */
1758 		if (mddev->new_level == 0) {
1759 			/* Can takeover raid10_near with raid disks divisable by data copies! */
1760 			if (near_copies > 1 &&
1761 			    !(mddev->raid_disks % near_copies)) {
1762 				mddev->raid_disks /= near_copies;
1763 				mddev->delta_disks = mddev->raid_disks;
1764 				return 0;
1765 			}
1766 
1767 			/* Can takeover raid10_far */
1768 			if (near_copies == 1 &&
1769 			    __raid10_far_copies(mddev->layout) > 1)
1770 				return 0;
1771 
1772 			break;
1773 		}
1774 
1775 		/* raid10_{near,far} -> raid1 */
1776 		if (mddev->new_level == 1 &&
1777 		    max(near_copies, __raid10_far_copies(mddev->layout)) == mddev->raid_disks)
1778 			return 0;
1779 
1780 		/* raid10_{near,far} with 2 disks -> raid4/5 */
1781 		if (__within_range(mddev->new_level, 4, 5) &&
1782 		    mddev->raid_disks == 2)
1783 			return 0;
1784 		break;
1785 
1786 	case 1:
1787 		/* raid1 with 2 disks -> raid4/5 */
1788 		if (__within_range(mddev->new_level, 4, 5) &&
1789 		    mddev->raid_disks == 2) {
1790 			mddev->degraded = 1;
1791 			return 0;
1792 		}
1793 
1794 		/* raid1 -> raid0 */
1795 		if (mddev->new_level == 0 &&
1796 		    mddev->raid_disks == 1)
1797 			return 0;
1798 
1799 		/* raid1 -> raid10 */
1800 		if (mddev->new_level == 10)
1801 			return 0;
1802 		break;
1803 
1804 	case 4:
1805 		/* raid4 -> raid0 */
1806 		if (mddev->new_level == 0)
1807 			return 0;
1808 
1809 		/* raid4 -> raid1/5 with 2 disks */
1810 		if ((mddev->new_level == 1 || mddev->new_level == 5) &&
1811 		    mddev->raid_disks == 2)
1812 			return 0;
1813 
1814 		/* raid4 -> raid5/6 with parity N */
1815 		if (__within_range(mddev->new_level, 5, 6) &&
1816 		    mddev->layout == ALGORITHM_PARITY_N)
1817 			return 0;
1818 		break;
1819 
1820 	case 5:
1821 		/* raid5 with parity N -> raid0 */
1822 		if (mddev->new_level == 0 &&
1823 		    mddev->layout == ALGORITHM_PARITY_N)
1824 			return 0;
1825 
1826 		/* raid5 with parity N -> raid4 */
1827 		if (mddev->new_level == 4 &&
1828 		    mddev->layout == ALGORITHM_PARITY_N)
1829 			return 0;
1830 
1831 		/* raid5 with 2 disks -> raid1/4/10 */
1832 		if ((mddev->new_level == 1 || mddev->new_level == 4 || mddev->new_level == 10) &&
1833 		    mddev->raid_disks == 2)
1834 			return 0;
1835 
1836 		/* raid5_* ->  raid6_*_6 with Q-Syndrome N (e.g. raid5_ra -> raid6_ra_6 */
1837 		if (mddev->new_level == 6 &&
1838 		    ((mddev->layout == ALGORITHM_PARITY_N && mddev->new_layout == ALGORITHM_PARITY_N) ||
1839 		      __within_range(mddev->new_layout, ALGORITHM_LEFT_ASYMMETRIC_6, ALGORITHM_RIGHT_SYMMETRIC_6)))
1840 			return 0;
1841 		break;
1842 
1843 	case 6:
1844 		/* raid6 with parity N -> raid0 */
1845 		if (mddev->new_level == 0 &&
1846 		    mddev->layout == ALGORITHM_PARITY_N)
1847 			return 0;
1848 
1849 		/* raid6 with parity N -> raid4 */
1850 		if (mddev->new_level == 4 &&
1851 		    mddev->layout == ALGORITHM_PARITY_N)
1852 			return 0;
1853 
1854 		/* raid6_*_n with Q-Syndrome N -> raid5_* */
1855 		if (mddev->new_level == 5 &&
1856 		    ((mddev->layout == ALGORITHM_PARITY_N && mddev->new_layout == ALGORITHM_PARITY_N) ||
1857 		     __within_range(mddev->new_layout, ALGORITHM_LEFT_ASYMMETRIC, ALGORITHM_RIGHT_SYMMETRIC)))
1858 			return 0;
1859 		break;
1860 
1861 	default:
1862 		break;
1863 	}
1864 
1865 	rs->ti->error = "takeover not possible";
1866 	return -EINVAL;
1867 }
1868 
1869 /* True if @rs requested to be taken over */
1870 static bool rs_takeover_requested(struct raid_set *rs)
1871 {
1872 	return rs->md.new_level != rs->md.level;
1873 }
1874 
1875 /* True if layout is set to reshape. */
1876 static bool rs_is_layout_change(struct raid_set *rs, bool use_mddev)
1877 {
1878 	return (use_mddev ? rs->md.delta_disks : rs->delta_disks) ||
1879 	       rs->md.new_layout != rs->md.layout ||
1880 	       rs->md.new_chunk_sectors != rs->md.chunk_sectors;
1881 }
1882 
1883 /* True if @rs is requested to reshape by ctr */
1884 static bool rs_reshape_requested(struct raid_set *rs)
1885 {
1886 	bool change;
1887 	struct mddev *mddev = &rs->md;
1888 
1889 	if (rs_takeover_requested(rs))
1890 		return false;
1891 
1892 	if (rs_is_raid0(rs))
1893 		return false;
1894 
1895 	change = rs_is_layout_change(rs, false);
1896 
1897 	/* Historical case to support raid1 reshape without delta disks */
1898 	if (rs_is_raid1(rs)) {
1899 		if (rs->delta_disks)
1900 			return !!rs->delta_disks;
1901 
1902 		return !change &&
1903 		       mddev->raid_disks != rs->raid_disks;
1904 	}
1905 
1906 	if (rs_is_raid10(rs))
1907 		return change &&
1908 		       !__is_raid10_far(mddev->new_layout) &&
1909 		       rs->delta_disks >= 0;
1910 
1911 	return change;
1912 }
1913 
1914 /*  Features */
1915 #define	FEATURE_FLAG_SUPPORTS_V190	0x1 /* Supports extended superblock */
1916 
1917 /* State flags for sb->flags */
1918 #define	SB_FLAG_RESHAPE_ACTIVE		0x1
1919 #define	SB_FLAG_RESHAPE_BACKWARDS	0x2
1920 
1921 /*
1922  * This structure is never routinely used by userspace, unlike md superblocks.
1923  * Devices with this superblock should only ever be accessed via device-mapper.
1924  */
1925 #define DM_RAID_MAGIC 0x64526D44
1926 struct dm_raid_superblock {
1927 	__le32 magic;		/* "DmRd" */
1928 	__le32 compat_features;	/* Used to indicate compatible features (like 1.9.0 ondisk metadata extension) */
1929 
1930 	__le32 num_devices;	/* Number of devices in this raid set. (Max 64) */
1931 	__le32 array_position;	/* The position of this drive in the raid set */
1932 
1933 	__le64 events;		/* Incremented by md when superblock updated */
1934 	__le64 failed_devices;	/* Pre 1.9.0 part of bit field of devices to */
1935 				/* indicate failures (see extension below) */
1936 
1937 	/*
1938 	 * This offset tracks the progress of the repair or replacement of
1939 	 * an individual drive.
1940 	 */
1941 	__le64 disk_recovery_offset;
1942 
1943 	/*
1944 	 * This offset tracks the progress of the initial raid set
1945 	 * synchronisation/parity calculation.
1946 	 */
1947 	__le64 array_resync_offset;
1948 
1949 	/*
1950 	 * raid characteristics
1951 	 */
1952 	__le32 level;
1953 	__le32 layout;
1954 	__le32 stripe_sectors;
1955 
1956 	/********************************************************************
1957 	 * BELOW FOLLOW V1.9.0 EXTENSIONS TO THE PRISTINE SUPERBLOCK FORMAT!!!
1958 	 *
1959 	 * FEATURE_FLAG_SUPPORTS_V190 in the compat_features member indicates that those exist
1960 	 */
1961 
1962 	__le32 flags; /* Flags defining array states for reshaping */
1963 
1964 	/*
1965 	 * This offset tracks the progress of a raid
1966 	 * set reshape in order to be able to restart it
1967 	 */
1968 	__le64 reshape_position;
1969 
1970 	/*
1971 	 * These define the properties of the array in case of an interrupted reshape
1972 	 */
1973 	__le32 new_level;
1974 	__le32 new_layout;
1975 	__le32 new_stripe_sectors;
1976 	__le32 delta_disks;
1977 
1978 	__le64 array_sectors; /* Array size in sectors */
1979 
1980 	/*
1981 	 * Sector offsets to data on devices (reshaping).
1982 	 * Needed to support out of place reshaping, thus
1983 	 * not writing over any stripes whilst converting
1984 	 * them from old to new layout
1985 	 */
1986 	__le64 data_offset;
1987 	__le64 new_data_offset;
1988 
1989 	__le64 sectors; /* Used device size in sectors */
1990 
1991 	/*
1992 	 * Additional Bit field of devices indicating failures to support
1993 	 * up to 256 devices with the 1.9.0 on-disk metadata format
1994 	 */
1995 	__le64 extended_failed_devices[DISKS_ARRAY_ELEMS - 1];
1996 
1997 	__le32 incompat_features;	/* Used to indicate any incompatible features */
1998 
1999 	/* Always set rest up to logical block size to 0 when writing (see get_metadata_device() below). */
2000 } __packed;
2001 
2002 /*
2003  * Check for reshape constraints on raid set @rs:
2004  *
2005  * - reshape function non-existent
2006  * - degraded set
2007  * - ongoing recovery
2008  * - ongoing reshape
2009  *
2010  * Returns 0 if none or -EPERM if given constraint
2011  * and error message reference in @errmsg
2012  */
2013 static int rs_check_reshape(struct raid_set *rs)
2014 {
2015 	struct mddev *mddev = &rs->md;
2016 
2017 	if (!mddev->pers || !mddev->pers->check_reshape)
2018 		rs->ti->error = "Reshape not supported";
2019 	else if (mddev->degraded)
2020 		rs->ti->error = "Can't reshape degraded raid set";
2021 	else if (rs_is_recovering(rs))
2022 		rs->ti->error = "Convert request on recovering raid set prohibited";
2023 	else if (rs_is_reshaping(rs))
2024 		rs->ti->error = "raid set already reshaping!";
2025 	else if (!(rs_is_raid1(rs) || rs_is_raid10(rs) || rs_is_raid456(rs)))
2026 		rs->ti->error = "Reshaping only supported for raid1/4/5/6/10";
2027 	else
2028 		return 0;
2029 
2030 	return -EPERM;
2031 }
2032 
2033 static int read_disk_sb(struct md_rdev *rdev, int size, bool force_reload)
2034 {
2035 	BUG_ON(!rdev->sb_page);
2036 
2037 	if (rdev->sb_loaded && !force_reload)
2038 		return 0;
2039 
2040 	rdev->sb_loaded = 0;
2041 
2042 	if (!sync_page_io(rdev, 0, size, rdev->sb_page, REQ_OP_READ, true)) {
2043 		DMERR("Failed to read superblock of device at position %d",
2044 		      rdev->raid_disk);
2045 		md_error(rdev->mddev, rdev);
2046 		set_bit(Faulty, &rdev->flags);
2047 		return -EIO;
2048 	}
2049 
2050 	rdev->sb_loaded = 1;
2051 
2052 	return 0;
2053 }
2054 
2055 static void sb_retrieve_failed_devices(struct dm_raid_superblock *sb, uint64_t *failed_devices)
2056 {
2057 	failed_devices[0] = le64_to_cpu(sb->failed_devices);
2058 	memset(failed_devices + 1, 0, sizeof(sb->extended_failed_devices));
2059 
2060 	if (le32_to_cpu(sb->compat_features) & FEATURE_FLAG_SUPPORTS_V190) {
2061 		int i = ARRAY_SIZE(sb->extended_failed_devices);
2062 
2063 		while (i--)
2064 			failed_devices[i+1] = le64_to_cpu(sb->extended_failed_devices[i]);
2065 	}
2066 }
2067 
2068 static void sb_update_failed_devices(struct dm_raid_superblock *sb, uint64_t *failed_devices)
2069 {
2070 	int i = ARRAY_SIZE(sb->extended_failed_devices);
2071 
2072 	sb->failed_devices = cpu_to_le64(failed_devices[0]);
2073 	while (i--)
2074 		sb->extended_failed_devices[i] = cpu_to_le64(failed_devices[i+1]);
2075 }
2076 
2077 /*
2078  * Synchronize the superblock members with the raid set properties
2079  *
2080  * All superblock data is little endian.
2081  */
2082 static void super_sync(struct mddev *mddev, struct md_rdev *rdev)
2083 {
2084 	bool update_failed_devices = false;
2085 	unsigned int i;
2086 	uint64_t failed_devices[DISKS_ARRAY_ELEMS];
2087 	struct dm_raid_superblock *sb;
2088 	struct raid_set *rs = container_of(mddev, struct raid_set, md);
2089 
2090 	/* No metadata device, no superblock */
2091 	if (!rdev->meta_bdev)
2092 		return;
2093 
2094 	BUG_ON(!rdev->sb_page);
2095 
2096 	sb = page_address(rdev->sb_page);
2097 
2098 	sb_retrieve_failed_devices(sb, failed_devices);
2099 
2100 	for (i = 0; i < rs->raid_disks; i++)
2101 		if (!rs->dev[i].data_dev || test_bit(Faulty, &rs->dev[i].rdev.flags)) {
2102 			update_failed_devices = true;
2103 			set_bit(i, (void *) failed_devices);
2104 		}
2105 
2106 	if (update_failed_devices)
2107 		sb_update_failed_devices(sb, failed_devices);
2108 
2109 	sb->magic = cpu_to_le32(DM_RAID_MAGIC);
2110 	sb->compat_features = cpu_to_le32(FEATURE_FLAG_SUPPORTS_V190);
2111 
2112 	sb->num_devices = cpu_to_le32(mddev->raid_disks);
2113 	sb->array_position = cpu_to_le32(rdev->raid_disk);
2114 
2115 	sb->events = cpu_to_le64(mddev->events);
2116 
2117 	sb->disk_recovery_offset = cpu_to_le64(rdev->recovery_offset);
2118 	sb->array_resync_offset = cpu_to_le64(mddev->recovery_cp);
2119 
2120 	sb->level = cpu_to_le32(mddev->level);
2121 	sb->layout = cpu_to_le32(mddev->layout);
2122 	sb->stripe_sectors = cpu_to_le32(mddev->chunk_sectors);
2123 
2124 	/********************************************************************
2125 	 * BELOW FOLLOW V1.9.0 EXTENSIONS TO THE PRISTINE SUPERBLOCK FORMAT!!!
2126 	 *
2127 	 * FEATURE_FLAG_SUPPORTS_V190 in the compat_features member indicates that those exist
2128 	 */
2129 	sb->new_level = cpu_to_le32(mddev->new_level);
2130 	sb->new_layout = cpu_to_le32(mddev->new_layout);
2131 	sb->new_stripe_sectors = cpu_to_le32(mddev->new_chunk_sectors);
2132 
2133 	sb->delta_disks = cpu_to_le32(mddev->delta_disks);
2134 
2135 	smp_rmb(); /* Make sure we access most recent reshape position */
2136 	sb->reshape_position = cpu_to_le64(mddev->reshape_position);
2137 	if (le64_to_cpu(sb->reshape_position) != MaxSector) {
2138 		/* Flag ongoing reshape */
2139 		sb->flags |= cpu_to_le32(SB_FLAG_RESHAPE_ACTIVE);
2140 
2141 		if (mddev->delta_disks < 0 || mddev->reshape_backwards)
2142 			sb->flags |= cpu_to_le32(SB_FLAG_RESHAPE_BACKWARDS);
2143 	} else {
2144 		/* Clear reshape flags */
2145 		sb->flags &= ~(cpu_to_le32(SB_FLAG_RESHAPE_ACTIVE|SB_FLAG_RESHAPE_BACKWARDS));
2146 	}
2147 
2148 	sb->array_sectors = cpu_to_le64(mddev->array_sectors);
2149 	sb->data_offset = cpu_to_le64(rdev->data_offset);
2150 	sb->new_data_offset = cpu_to_le64(rdev->new_data_offset);
2151 	sb->sectors = cpu_to_le64(rdev->sectors);
2152 	sb->incompat_features = cpu_to_le32(0);
2153 
2154 	/* Zero out the rest of the payload after the size of the superblock */
2155 	memset(sb + 1, 0, rdev->sb_size - sizeof(*sb));
2156 }
2157 
2158 /*
2159  * super_load
2160  *
2161  * This function creates a superblock if one is not found on the device
2162  * and will decide which superblock to use if there's a choice.
2163  *
2164  * Return: 1 if use rdev, 0 if use refdev, -Exxx otherwise
2165  */
2166 static int super_load(struct md_rdev *rdev, struct md_rdev *refdev)
2167 {
2168 	int r;
2169 	struct dm_raid_superblock *sb;
2170 	struct dm_raid_superblock *refsb;
2171 	uint64_t events_sb, events_refsb;
2172 
2173 	r = read_disk_sb(rdev, rdev->sb_size, false);
2174 	if (r)
2175 		return r;
2176 
2177 	sb = page_address(rdev->sb_page);
2178 
2179 	/*
2180 	 * Two cases that we want to write new superblocks and rebuild:
2181 	 * 1) New device (no matching magic number)
2182 	 * 2) Device specified for rebuild (!In_sync w/ offset == 0)
2183 	 */
2184 	if ((sb->magic != cpu_to_le32(DM_RAID_MAGIC)) ||
2185 	    (!test_bit(In_sync, &rdev->flags) && !rdev->recovery_offset)) {
2186 		super_sync(rdev->mddev, rdev);
2187 
2188 		set_bit(FirstUse, &rdev->flags);
2189 		sb->compat_features = cpu_to_le32(FEATURE_FLAG_SUPPORTS_V190);
2190 
2191 		/* Force writing of superblocks to disk */
2192 		set_bit(MD_SB_CHANGE_DEVS, &rdev->mddev->sb_flags);
2193 
2194 		/* Any superblock is better than none, choose that if given */
2195 		return refdev ? 0 : 1;
2196 	}
2197 
2198 	if (!refdev)
2199 		return 1;
2200 
2201 	events_sb = le64_to_cpu(sb->events);
2202 
2203 	refsb = page_address(refdev->sb_page);
2204 	events_refsb = le64_to_cpu(refsb->events);
2205 
2206 	return (events_sb > events_refsb) ? 1 : 0;
2207 }
2208 
2209 static int super_init_validation(struct raid_set *rs, struct md_rdev *rdev)
2210 {
2211 	int role;
2212 	struct mddev *mddev = &rs->md;
2213 	uint64_t events_sb;
2214 	uint64_t failed_devices[DISKS_ARRAY_ELEMS];
2215 	struct dm_raid_superblock *sb;
2216 	uint32_t new_devs = 0, rebuild_and_new = 0, rebuilds = 0;
2217 	struct md_rdev *r;
2218 	struct dm_raid_superblock *sb2;
2219 
2220 	sb = page_address(rdev->sb_page);
2221 	events_sb = le64_to_cpu(sb->events);
2222 
2223 	/*
2224 	 * Initialise to 1 if this is a new superblock.
2225 	 */
2226 	mddev->events = events_sb ? : 1;
2227 
2228 	mddev->reshape_position = MaxSector;
2229 
2230 	mddev->raid_disks = le32_to_cpu(sb->num_devices);
2231 	mddev->level = le32_to_cpu(sb->level);
2232 	mddev->layout = le32_to_cpu(sb->layout);
2233 	mddev->chunk_sectors = le32_to_cpu(sb->stripe_sectors);
2234 
2235 	/*
2236 	 * Reshaping is supported, e.g. reshape_position is valid
2237 	 * in superblock and superblock content is authoritative.
2238 	 */
2239 	if (le32_to_cpu(sb->compat_features) & FEATURE_FLAG_SUPPORTS_V190) {
2240 		/* Superblock is authoritative wrt given raid set layout! */
2241 		mddev->new_level = le32_to_cpu(sb->new_level);
2242 		mddev->new_layout = le32_to_cpu(sb->new_layout);
2243 		mddev->new_chunk_sectors = le32_to_cpu(sb->new_stripe_sectors);
2244 		mddev->delta_disks = le32_to_cpu(sb->delta_disks);
2245 		mddev->array_sectors = le64_to_cpu(sb->array_sectors);
2246 
2247 		/* raid was reshaping and got interrupted */
2248 		if (le32_to_cpu(sb->flags) & SB_FLAG_RESHAPE_ACTIVE) {
2249 			if (test_bit(__CTR_FLAG_DELTA_DISKS, &rs->ctr_flags)) {
2250 				DMERR("Reshape requested but raid set is still reshaping");
2251 				return -EINVAL;
2252 			}
2253 
2254 			if (mddev->delta_disks < 0 ||
2255 			    (!mddev->delta_disks && (le32_to_cpu(sb->flags) & SB_FLAG_RESHAPE_BACKWARDS)))
2256 				mddev->reshape_backwards = 1;
2257 			else
2258 				mddev->reshape_backwards = 0;
2259 
2260 			mddev->reshape_position = le64_to_cpu(sb->reshape_position);
2261 			rs->raid_type = get_raid_type_by_ll(mddev->level, mddev->layout);
2262 		}
2263 
2264 	} else {
2265 		/*
2266 		 * No takeover/reshaping, because we don't have the extended v1.9.0 metadata
2267 		 */
2268 		struct raid_type *rt_cur = get_raid_type_by_ll(mddev->level, mddev->layout);
2269 		struct raid_type *rt_new = get_raid_type_by_ll(mddev->new_level, mddev->new_layout);
2270 
2271 		if (rs_takeover_requested(rs)) {
2272 			if (rt_cur && rt_new)
2273 				DMERR("Takeover raid sets from %s to %s not yet supported by metadata. (raid level change)",
2274 				      rt_cur->name, rt_new->name);
2275 			else
2276 				DMERR("Takeover raid sets not yet supported by metadata. (raid level change)");
2277 			return -EINVAL;
2278 		} else if (rs_reshape_requested(rs)) {
2279 			DMERR("Reshaping raid sets not yet supported by metadata. (raid layout change keeping level)");
2280 			if (mddev->layout != mddev->new_layout) {
2281 				if (rt_cur && rt_new)
2282 					DMERR("	 current layout %s vs new layout %s",
2283 					      rt_cur->name, rt_new->name);
2284 				else
2285 					DMERR("	 current layout 0x%X vs new layout 0x%X",
2286 					      le32_to_cpu(sb->layout), mddev->new_layout);
2287 			}
2288 			if (mddev->chunk_sectors != mddev->new_chunk_sectors)
2289 				DMERR("	 current stripe sectors %u vs new stripe sectors %u",
2290 				      mddev->chunk_sectors, mddev->new_chunk_sectors);
2291 			if (rs->delta_disks)
2292 				DMERR("	 current %u disks vs new %u disks",
2293 				      mddev->raid_disks, mddev->raid_disks + rs->delta_disks);
2294 			if (rs_is_raid10(rs)) {
2295 				DMERR("	 Old layout: %s w/ %u copies",
2296 				      raid10_md_layout_to_format(mddev->layout),
2297 				      raid10_md_layout_to_copies(mddev->layout));
2298 				DMERR("	 New layout: %s w/ %u copies",
2299 				      raid10_md_layout_to_format(mddev->new_layout),
2300 				      raid10_md_layout_to_copies(mddev->new_layout));
2301 			}
2302 			return -EINVAL;
2303 		}
2304 
2305 		DMINFO("Discovered old metadata format; upgrading to extended metadata format");
2306 	}
2307 
2308 	if (!test_bit(__CTR_FLAG_NOSYNC, &rs->ctr_flags))
2309 		mddev->recovery_cp = le64_to_cpu(sb->array_resync_offset);
2310 
2311 	/*
2312 	 * During load, we set FirstUse if a new superblock was written.
2313 	 * There are two reasons we might not have a superblock:
2314 	 * 1) The raid set is brand new - in which case, all of the
2315 	 *    devices must have their In_sync bit set.	Also,
2316 	 *    recovery_cp must be 0, unless forced.
2317 	 * 2) This is a new device being added to an old raid set
2318 	 *    and the new device needs to be rebuilt - in which
2319 	 *    case the In_sync bit will /not/ be set and
2320 	 *    recovery_cp must be MaxSector.
2321 	 * 3) This is/are a new device(s) being added to an old
2322 	 *    raid set during takeover to a higher raid level
2323 	 *    to provide capacity for redundancy or during reshape
2324 	 *    to add capacity to grow the raid set.
2325 	 */
2326 	rdev_for_each(r, mddev) {
2327 		if (test_bit(Journal, &rdev->flags))
2328 			continue;
2329 
2330 		if (test_bit(FirstUse, &r->flags))
2331 			new_devs++;
2332 
2333 		if (!test_bit(In_sync, &r->flags)) {
2334 			DMINFO("Device %d specified for rebuild; clearing superblock",
2335 				r->raid_disk);
2336 			rebuilds++;
2337 
2338 			if (test_bit(FirstUse, &r->flags))
2339 				rebuild_and_new++;
2340 		}
2341 	}
2342 
2343 	if (new_devs == rs->raid_disks || !rebuilds) {
2344 		/* Replace a broken device */
2345 		if (new_devs == rs->raid_disks) {
2346 			DMINFO("Superblocks created for new raid set");
2347 			set_bit(MD_ARRAY_FIRST_USE, &mddev->flags);
2348 		} else if (new_devs != rebuilds &&
2349 			   new_devs != rs->delta_disks) {
2350 			DMERR("New device injected into existing raid set without "
2351 			      "'delta_disks' or 'rebuild' parameter specified");
2352 			return -EINVAL;
2353 		}
2354 	} else if (new_devs && new_devs != rebuilds) {
2355 		DMERR("%u 'rebuild' devices cannot be injected into"
2356 		      " a raid set with %u other first-time devices",
2357 		      rebuilds, new_devs);
2358 		return -EINVAL;
2359 	} else if (rebuilds) {
2360 		if (rebuild_and_new && rebuilds != rebuild_and_new) {
2361 			DMERR("new device%s provided without 'rebuild'",
2362 			      new_devs > 1 ? "s" : "");
2363 			return -EINVAL;
2364 		} else if (!test_bit(__CTR_FLAG_REBUILD, &rs->ctr_flags) && rs_is_recovering(rs)) {
2365 			DMERR("'rebuild' specified while raid set is not in-sync (recovery_cp=%llu)",
2366 			      (unsigned long long) mddev->recovery_cp);
2367 			return -EINVAL;
2368 		} else if (rs_is_reshaping(rs)) {
2369 			DMERR("'rebuild' specified while raid set is being reshaped (reshape_position=%llu)",
2370 			      (unsigned long long) mddev->reshape_position);
2371 			return -EINVAL;
2372 		}
2373 	}
2374 
2375 	/*
2376 	 * Now we set the Faulty bit for those devices that are
2377 	 * recorded in the superblock as failed.
2378 	 */
2379 	sb_retrieve_failed_devices(sb, failed_devices);
2380 	rdev_for_each(r, mddev) {
2381 		if (test_bit(Journal, &rdev->flags) ||
2382 		    !r->sb_page)
2383 			continue;
2384 		sb2 = page_address(r->sb_page);
2385 		sb2->failed_devices = 0;
2386 		memset(sb2->extended_failed_devices, 0, sizeof(sb2->extended_failed_devices));
2387 
2388 		/*
2389 		 * Check for any device re-ordering.
2390 		 */
2391 		if (!test_bit(FirstUse, &r->flags) && (r->raid_disk >= 0)) {
2392 			role = le32_to_cpu(sb2->array_position);
2393 			if (role < 0)
2394 				continue;
2395 
2396 			if (role != r->raid_disk) {
2397 				if (rs_is_raid10(rs) && __is_raid10_near(mddev->layout)) {
2398 					if (mddev->raid_disks % __raid10_near_copies(mddev->layout) ||
2399 					    rs->raid_disks % rs->raid10_copies) {
2400 						rs->ti->error =
2401 							"Cannot change raid10 near set to odd # of devices!";
2402 						return -EINVAL;
2403 					}
2404 
2405 					sb2->array_position = cpu_to_le32(r->raid_disk);
2406 
2407 				} else if (!(rs_is_raid10(rs) && rt_is_raid0(rs->raid_type)) &&
2408 					   !(rs_is_raid0(rs) && rt_is_raid10(rs->raid_type)) &&
2409 					   !rt_is_raid1(rs->raid_type)) {
2410 					rs->ti->error = "Cannot change device positions in raid set";
2411 					return -EINVAL;
2412 				}
2413 
2414 				DMINFO("raid device #%d now at position #%d", role, r->raid_disk);
2415 			}
2416 
2417 			/*
2418 			 * Partial recovery is performed on
2419 			 * returning failed devices.
2420 			 */
2421 			if (test_bit(role, (void *) failed_devices))
2422 				set_bit(Faulty, &r->flags);
2423 		}
2424 	}
2425 
2426 	return 0;
2427 }
2428 
2429 static int super_validate(struct raid_set *rs, struct md_rdev *rdev)
2430 {
2431 	struct mddev *mddev = &rs->md;
2432 	struct dm_raid_superblock *sb;
2433 
2434 	if (rs_is_raid0(rs) || !rdev->sb_page || rdev->raid_disk < 0)
2435 		return 0;
2436 
2437 	sb = page_address(rdev->sb_page);
2438 
2439 	/*
2440 	 * If mddev->events is not set, we know we have not yet initialized
2441 	 * the array.
2442 	 */
2443 	if (!mddev->events && super_init_validation(rs, rdev))
2444 		return -EINVAL;
2445 
2446 	if (le32_to_cpu(sb->compat_features) &&
2447 	    le32_to_cpu(sb->compat_features) != FEATURE_FLAG_SUPPORTS_V190) {
2448 		rs->ti->error = "Unable to assemble array: Unknown flag(s) in compatible feature flags";
2449 		return -EINVAL;
2450 	}
2451 
2452 	if (sb->incompat_features) {
2453 		rs->ti->error = "Unable to assemble array: No incompatible feature flags supported yet";
2454 		return -EINVAL;
2455 	}
2456 
2457 	/* Enable bitmap creation on @rs unless no metadevs or raid0 or journaled raid4/5/6 set. */
2458 	mddev->bitmap_info.offset = (rt_is_raid0(rs->raid_type) || rs->journal_dev.dev) ? 0 : to_sector(4096);
2459 	mddev->bitmap_info.default_offset = mddev->bitmap_info.offset;
2460 
2461 	if (!test_and_clear_bit(FirstUse, &rdev->flags)) {
2462 		/*
2463 		 * Retrieve rdev size stored in superblock to be prepared for shrink.
2464 		 * Check extended superblock members are present otherwise the size
2465 		 * will not be set!
2466 		 */
2467 		if (le32_to_cpu(sb->compat_features) & FEATURE_FLAG_SUPPORTS_V190)
2468 			rdev->sectors = le64_to_cpu(sb->sectors);
2469 
2470 		rdev->recovery_offset = le64_to_cpu(sb->disk_recovery_offset);
2471 		if (rdev->recovery_offset == MaxSector)
2472 			set_bit(In_sync, &rdev->flags);
2473 		/*
2474 		 * If no reshape in progress -> we're recovering single
2475 		 * disk(s) and have to set the device(s) to out-of-sync
2476 		 */
2477 		else if (!rs_is_reshaping(rs))
2478 			clear_bit(In_sync, &rdev->flags); /* Mandatory for recovery */
2479 	}
2480 
2481 	/*
2482 	 * If a device comes back, set it as not In_sync and no longer faulty.
2483 	 */
2484 	if (test_and_clear_bit(Faulty, &rdev->flags)) {
2485 		rdev->recovery_offset = 0;
2486 		clear_bit(In_sync, &rdev->flags);
2487 		rdev->saved_raid_disk = rdev->raid_disk;
2488 	}
2489 
2490 	/* Reshape support -> restore repective data offsets */
2491 	rdev->data_offset = le64_to_cpu(sb->data_offset);
2492 	rdev->new_data_offset = le64_to_cpu(sb->new_data_offset);
2493 
2494 	return 0;
2495 }
2496 
2497 /*
2498  * Analyse superblocks and select the freshest.
2499  */
2500 static int analyse_superblocks(struct dm_target *ti, struct raid_set *rs)
2501 {
2502 	int r;
2503 	struct md_rdev *rdev, *freshest;
2504 	struct mddev *mddev = &rs->md;
2505 
2506 	freshest = NULL;
2507 	rdev_for_each(rdev, mddev) {
2508 		if (test_bit(Journal, &rdev->flags))
2509 			continue;
2510 
2511 		if (!rdev->meta_bdev)
2512 			continue;
2513 
2514 		/* Set superblock offset/size for metadata device. */
2515 		rdev->sb_start = 0;
2516 		rdev->sb_size = bdev_logical_block_size(rdev->meta_bdev);
2517 		if (rdev->sb_size < sizeof(struct dm_raid_superblock) || rdev->sb_size > PAGE_SIZE) {
2518 			DMERR("superblock size of a logical block is no longer valid");
2519 			return -EINVAL;
2520 		}
2521 
2522 		/*
2523 		 * Skipping super_load due to CTR_FLAG_SYNC will cause
2524 		 * the array to undergo initialization again as
2525 		 * though it were new.	This is the intended effect
2526 		 * of the "sync" directive.
2527 		 *
2528 		 * With reshaping capability added, we must ensure that
2529 		 * the "sync" directive is disallowed during the reshape.
2530 		 */
2531 		if (test_bit(__CTR_FLAG_SYNC, &rs->ctr_flags))
2532 			continue;
2533 
2534 		r = super_load(rdev, freshest);
2535 
2536 		switch (r) {
2537 		case 1:
2538 			freshest = rdev;
2539 			break;
2540 		case 0:
2541 			break;
2542 		default:
2543 			/* This is a failure to read the superblock from the metadata device. */
2544 			/*
2545 			 * We have to keep any raid0 data/metadata device pairs or
2546 			 * the MD raid0 personality will fail to start the array.
2547 			 */
2548 			if (rs_is_raid0(rs))
2549 				continue;
2550 
2551 			/*
2552 			 * We keep the dm_devs to be able to emit the device tuple
2553 			 * properly on the table line in raid_status() (rather than
2554 			 * mistakenly acting as if '- -' got passed into the constructor).
2555 			 *
2556 			 * The rdev has to stay on the same_set list to allow for
2557 			 * the attempt to restore faulty devices on second resume.
2558 			 */
2559 			rdev->raid_disk = rdev->saved_raid_disk = -1;
2560 			break;
2561 		}
2562 	}
2563 
2564 	if (!freshest)
2565 		return 0;
2566 
2567 	/*
2568 	 * Validation of the freshest device provides the source of
2569 	 * validation for the remaining devices.
2570 	 */
2571 	rs->ti->error = "Unable to assemble array: Invalid superblocks";
2572 	if (super_validate(rs, freshest))
2573 		return -EINVAL;
2574 
2575 	if (validate_raid_redundancy(rs)) {
2576 		rs->ti->error = "Insufficient redundancy to activate array";
2577 		return -EINVAL;
2578 	}
2579 
2580 	rdev_for_each(rdev, mddev)
2581 		if (!test_bit(Journal, &rdev->flags) &&
2582 		    rdev != freshest &&
2583 		    super_validate(rs, rdev))
2584 			return -EINVAL;
2585 	return 0;
2586 }
2587 
2588 /*
2589  * Adjust data_offset and new_data_offset on all disk members of @rs
2590  * for out of place reshaping if requested by constructor
2591  *
2592  * We need free space at the beginning of each raid disk for forward
2593  * and at the end for backward reshapes which userspace has to provide
2594  * via remapping/reordering of space.
2595  */
2596 static int rs_adjust_data_offsets(struct raid_set *rs)
2597 {
2598 	sector_t data_offset = 0, new_data_offset = 0;
2599 	struct md_rdev *rdev;
2600 
2601 	/* Constructor did not request data offset change */
2602 	if (!test_bit(__CTR_FLAG_DATA_OFFSET, &rs->ctr_flags)) {
2603 		if (!rs_is_reshapable(rs))
2604 			goto out;
2605 
2606 		return 0;
2607 	}
2608 
2609 	/* HM FIXME: get In_Sync raid_dev? */
2610 	rdev = &rs->dev[0].rdev;
2611 
2612 	if (rs->delta_disks < 0) {
2613 		/*
2614 		 * Removing disks (reshaping backwards):
2615 		 *
2616 		 * - before reshape: data is at offset 0 and free space
2617 		 *		     is at end of each component LV
2618 		 *
2619 		 * - after reshape: data is at offset rs->data_offset != 0 on each component LV
2620 		 */
2621 		data_offset = 0;
2622 		new_data_offset = rs->data_offset;
2623 
2624 	} else if (rs->delta_disks > 0) {
2625 		/*
2626 		 * Adding disks (reshaping forwards):
2627 		 *
2628 		 * - before reshape: data is at offset rs->data_offset != 0 and
2629 		 *		     free space is at begin of each component LV
2630 		 *
2631 		 * - after reshape: data is at offset 0 on each component LV
2632 		 */
2633 		data_offset = rs->data_offset;
2634 		new_data_offset = 0;
2635 
2636 	} else {
2637 		/*
2638 		 * User space passes in 0 for data offset after having removed reshape space
2639 		 *
2640 		 * - or - (data offset != 0)
2641 		 *
2642 		 * Changing RAID layout or chunk size -> toggle offsets
2643 		 *
2644 		 * - before reshape: data is at offset rs->data_offset 0 and
2645 		 *		     free space is at end of each component LV
2646 		 *		     -or-
2647 		 *                   data is at offset rs->data_offset != 0 and
2648 		 *		     free space is at begin of each component LV
2649 		 *
2650 		 * - after reshape: data is at offset 0 if it was at offset != 0
2651 		 *                  or at offset != 0 if it was at offset 0
2652 		 *                  on each component LV
2653 		 *
2654 		 */
2655 		data_offset = rs->data_offset ? rdev->data_offset : 0;
2656 		new_data_offset = data_offset ? 0 : rs->data_offset;
2657 		set_bit(RT_FLAG_UPDATE_SBS, &rs->runtime_flags);
2658 	}
2659 
2660 	/*
2661 	 * Make sure we got a minimum amount of free sectors per device
2662 	 */
2663 	if (rs->data_offset &&
2664 	    bdev_nr_sectors(rdev->bdev) - rs->md.dev_sectors < MIN_FREE_RESHAPE_SPACE) {
2665 		rs->ti->error = data_offset ? "No space for forward reshape" :
2666 					      "No space for backward reshape";
2667 		return -ENOSPC;
2668 	}
2669 out:
2670 	/*
2671 	 * Raise recovery_cp in case data_offset != 0 to
2672 	 * avoid false recovery positives in the constructor.
2673 	 */
2674 	if (rs->md.recovery_cp < rs->md.dev_sectors)
2675 		rs->md.recovery_cp += rs->dev[0].rdev.data_offset;
2676 
2677 	/* Adjust data offsets on all rdevs but on any raid4/5/6 journal device */
2678 	rdev_for_each(rdev, &rs->md) {
2679 		if (!test_bit(Journal, &rdev->flags)) {
2680 			rdev->data_offset = data_offset;
2681 			rdev->new_data_offset = new_data_offset;
2682 		}
2683 	}
2684 
2685 	return 0;
2686 }
2687 
2688 /* Userpace reordered disks -> adjust raid_disk indexes in @rs */
2689 static void __reorder_raid_disk_indexes(struct raid_set *rs)
2690 {
2691 	int i = 0;
2692 	struct md_rdev *rdev;
2693 
2694 	rdev_for_each(rdev, &rs->md) {
2695 		if (!test_bit(Journal, &rdev->flags)) {
2696 			rdev->raid_disk = i++;
2697 			rdev->saved_raid_disk = rdev->new_raid_disk = -1;
2698 		}
2699 	}
2700 }
2701 
2702 /*
2703  * Setup @rs for takeover by a different raid level
2704  */
2705 static int rs_setup_takeover(struct raid_set *rs)
2706 {
2707 	struct mddev *mddev = &rs->md;
2708 	struct md_rdev *rdev;
2709 	unsigned int d = mddev->raid_disks = rs->raid_disks;
2710 	sector_t new_data_offset = rs->dev[0].rdev.data_offset ? 0 : rs->data_offset;
2711 
2712 	if (rt_is_raid10(rs->raid_type)) {
2713 		if (rs_is_raid0(rs)) {
2714 			/* Userpace reordered disks -> adjust raid_disk indexes */
2715 			__reorder_raid_disk_indexes(rs);
2716 
2717 			/* raid0 -> raid10_far layout */
2718 			mddev->layout = raid10_format_to_md_layout(rs, ALGORITHM_RAID10_FAR,
2719 								   rs->raid10_copies);
2720 		} else if (rs_is_raid1(rs))
2721 			/* raid1 -> raid10_near layout */
2722 			mddev->layout = raid10_format_to_md_layout(rs, ALGORITHM_RAID10_NEAR,
2723 								   rs->raid_disks);
2724 		else
2725 			return -EINVAL;
2726 
2727 	}
2728 
2729 	clear_bit(MD_ARRAY_FIRST_USE, &mddev->flags);
2730 	mddev->recovery_cp = MaxSector;
2731 
2732 	while (d--) {
2733 		rdev = &rs->dev[d].rdev;
2734 
2735 		if (test_bit(d, (void *) rs->rebuild_disks)) {
2736 			clear_bit(In_sync, &rdev->flags);
2737 			clear_bit(Faulty, &rdev->flags);
2738 			mddev->recovery_cp = rdev->recovery_offset = 0;
2739 			/* Bitmap has to be created when we do an "up" takeover */
2740 			set_bit(MD_ARRAY_FIRST_USE, &mddev->flags);
2741 		}
2742 
2743 		rdev->new_data_offset = new_data_offset;
2744 	}
2745 
2746 	return 0;
2747 }
2748 
2749 /* Prepare @rs for reshape */
2750 static int rs_prepare_reshape(struct raid_set *rs)
2751 {
2752 	bool reshape;
2753 	struct mddev *mddev = &rs->md;
2754 
2755 	if (rs_is_raid10(rs)) {
2756 		if (rs->raid_disks != mddev->raid_disks &&
2757 		    __is_raid10_near(mddev->layout) &&
2758 		    rs->raid10_copies &&
2759 		    rs->raid10_copies != __raid10_near_copies(mddev->layout)) {
2760 			/*
2761 			 * raid disk have to be multiple of data copies to allow this conversion,
2762 			 *
2763 			 * This is actually not a reshape it is a
2764 			 * rebuild of any additional mirrors per group
2765 			 */
2766 			if (rs->raid_disks % rs->raid10_copies) {
2767 				rs->ti->error = "Can't reshape raid10 mirror groups";
2768 				return -EINVAL;
2769 			}
2770 
2771 			/* Userpace reordered disks to add/remove mirrors -> adjust raid_disk indexes */
2772 			__reorder_raid_disk_indexes(rs);
2773 			mddev->layout = raid10_format_to_md_layout(rs, ALGORITHM_RAID10_NEAR,
2774 								   rs->raid10_copies);
2775 			mddev->new_layout = mddev->layout;
2776 			reshape = false;
2777 		} else
2778 			reshape = true;
2779 
2780 	} else if (rs_is_raid456(rs))
2781 		reshape = true;
2782 
2783 	else if (rs_is_raid1(rs)) {
2784 		if (rs->delta_disks) {
2785 			/* Process raid1 via delta_disks */
2786 			mddev->degraded = rs->delta_disks < 0 ? -rs->delta_disks : rs->delta_disks;
2787 			reshape = true;
2788 		} else {
2789 			/* Process raid1 without delta_disks */
2790 			mddev->raid_disks = rs->raid_disks;
2791 			reshape = false;
2792 		}
2793 	} else {
2794 		rs->ti->error = "Called with bogus raid type";
2795 		return -EINVAL;
2796 	}
2797 
2798 	if (reshape) {
2799 		set_bit(RT_FLAG_RESHAPE_RS, &rs->runtime_flags);
2800 		set_bit(RT_FLAG_UPDATE_SBS, &rs->runtime_flags);
2801 	} else if (mddev->raid_disks < rs->raid_disks)
2802 		/* Create new superblocks and bitmaps, if any new disks */
2803 		set_bit(RT_FLAG_UPDATE_SBS, &rs->runtime_flags);
2804 
2805 	return 0;
2806 }
2807 
2808 /* Get reshape sectors from data_offsets or raid set */
2809 static sector_t _get_reshape_sectors(struct raid_set *rs)
2810 {
2811 	struct md_rdev *rdev;
2812 	sector_t reshape_sectors = 0;
2813 
2814 	rdev_for_each(rdev, &rs->md)
2815 		if (!test_bit(Journal, &rdev->flags)) {
2816 			reshape_sectors = (rdev->data_offset > rdev->new_data_offset) ?
2817 					rdev->data_offset - rdev->new_data_offset :
2818 					rdev->new_data_offset - rdev->data_offset;
2819 			break;
2820 		}
2821 
2822 	return max(reshape_sectors, (sector_t) rs->data_offset);
2823 }
2824 
2825 /*
2826  * Reshape:
2827  * - change raid layout
2828  * - change chunk size
2829  * - add disks
2830  * - remove disks
2831  */
2832 static int rs_setup_reshape(struct raid_set *rs)
2833 {
2834 	int r = 0;
2835 	unsigned int cur_raid_devs, d;
2836 	sector_t reshape_sectors = _get_reshape_sectors(rs);
2837 	struct mddev *mddev = &rs->md;
2838 	struct md_rdev *rdev;
2839 
2840 	mddev->delta_disks = rs->delta_disks;
2841 	cur_raid_devs = mddev->raid_disks;
2842 
2843 	/* Ignore impossible layout change whilst adding/removing disks */
2844 	if (mddev->delta_disks &&
2845 	    mddev->layout != mddev->new_layout) {
2846 		DMINFO("Ignoring invalid layout change with delta_disks=%d", rs->delta_disks);
2847 		mddev->new_layout = mddev->layout;
2848 	}
2849 
2850 	/*
2851 	 * Adjust array size:
2852 	 *
2853 	 * - in case of adding disk(s), array size has
2854 	 *   to grow after the disk adding reshape,
2855 	 *   which'll happen in the event handler;
2856 	 *   reshape will happen forward, so space has to
2857 	 *   be available at the beginning of each disk
2858 	 *
2859 	 * - in case of removing disk(s), array size
2860 	 *   has to shrink before starting the reshape,
2861 	 *   which'll happen here;
2862 	 *   reshape will happen backward, so space has to
2863 	 *   be available at the end of each disk
2864 	 *
2865 	 * - data_offset and new_data_offset are
2866 	 *   adjusted for aforementioned out of place
2867 	 *   reshaping based on userspace passing in
2868 	 *   the "data_offset <sectors>" key/value
2869 	 *   pair via the constructor
2870 	 */
2871 
2872 	/* Add disk(s) */
2873 	if (rs->delta_disks > 0) {
2874 		/* Prepare disks for check in raid4/5/6/10 {check|start}_reshape */
2875 		for (d = cur_raid_devs; d < rs->raid_disks; d++) {
2876 			rdev = &rs->dev[d].rdev;
2877 			clear_bit(In_sync, &rdev->flags);
2878 
2879 			/*
2880 			 * save_raid_disk needs to be -1, or recovery_offset will be set to 0
2881 			 * by md, which'll store that erroneously in the superblock on reshape
2882 			 */
2883 			rdev->saved_raid_disk = -1;
2884 			rdev->raid_disk = d;
2885 
2886 			rdev->sectors = mddev->dev_sectors;
2887 			rdev->recovery_offset = rs_is_raid1(rs) ? 0 : MaxSector;
2888 		}
2889 
2890 		mddev->reshape_backwards = 0; /* adding disk(s) -> forward reshape */
2891 
2892 	/* Remove disk(s) */
2893 	} else if (rs->delta_disks < 0) {
2894 		r = rs_set_dev_and_array_sectors(rs, rs->ti->len, true);
2895 		mddev->reshape_backwards = 1; /* removing disk(s) -> backward reshape */
2896 
2897 	/* Change layout and/or chunk size */
2898 	} else {
2899 		/*
2900 		 * Reshape layout (e.g. raid5_ls -> raid5_n) and/or chunk size:
2901 		 *
2902 		 * keeping number of disks and do layout change ->
2903 		 *
2904 		 * toggle reshape_backward depending on data_offset:
2905 		 *
2906 		 * - free space upfront -> reshape forward
2907 		 *
2908 		 * - free space at the end -> reshape backward
2909 		 *
2910 		 *
2911 		 * This utilizes free reshape space avoiding the need
2912 		 * for userspace to move (parts of) LV segments in
2913 		 * case of layout/chunksize change  (for disk
2914 		 * adding/removing reshape space has to be at
2915 		 * the proper address (see above with delta_disks):
2916 		 *
2917 		 * add disk(s)   -> begin
2918 		 * remove disk(s)-> end
2919 		 */
2920 		mddev->reshape_backwards = rs->dev[0].rdev.data_offset ? 0 : 1;
2921 	}
2922 
2923 	/*
2924 	 * Adjust device size for forward reshape
2925 	 * because md_finish_reshape() reduces it.
2926 	 */
2927 	if (!mddev->reshape_backwards)
2928 		rdev_for_each(rdev, &rs->md)
2929 			if (!test_bit(Journal, &rdev->flags))
2930 				rdev->sectors += reshape_sectors;
2931 
2932 	return r;
2933 }
2934 
2935 /*
2936  * If the md resync thread has updated superblock with max reshape position
2937  * at the end of a reshape but not (yet) reset the layout configuration
2938  * changes -> reset the latter.
2939  */
2940 static void rs_reset_inconclusive_reshape(struct raid_set *rs)
2941 {
2942 	if (!rs_is_reshaping(rs) && rs_is_layout_change(rs, true)) {
2943 		rs_set_cur(rs);
2944 		rs->md.delta_disks = 0;
2945 		rs->md.reshape_backwards = 0;
2946 	}
2947 }
2948 
2949 /*
2950  * Enable/disable discard support on RAID set depending on
2951  * RAID level and discard properties of underlying RAID members.
2952  */
2953 static void configure_discard_support(struct raid_set *rs)
2954 {
2955 	int i;
2956 	bool raid456;
2957 	struct dm_target *ti = rs->ti;
2958 
2959 	/*
2960 	 * XXX: RAID level 4,5,6 require zeroing for safety.
2961 	 */
2962 	raid456 = rs_is_raid456(rs);
2963 
2964 	for (i = 0; i < rs->raid_disks; i++) {
2965 		if (!rs->dev[i].rdev.bdev ||
2966 		    !bdev_max_discard_sectors(rs->dev[i].rdev.bdev))
2967 			return;
2968 
2969 		if (raid456) {
2970 			if (!devices_handle_discard_safely) {
2971 				DMERR("raid456 discard support disabled due to discard_zeroes_data uncertainty.");
2972 				DMERR("Set dm-raid.devices_handle_discard_safely=Y to override.");
2973 				return;
2974 			}
2975 		}
2976 	}
2977 
2978 	ti->num_discard_bios = 1;
2979 }
2980 
2981 /*
2982  * Construct a RAID0/1/10/4/5/6 mapping:
2983  * Args:
2984  *	<raid_type> <#raid_params> <raid_params>{0,}	\
2985  *	<#raid_devs> [<meta_dev1> <dev1>]{1,}
2986  *
2987  * <raid_params> varies by <raid_type>.	 See 'parse_raid_params' for
2988  * details on possible <raid_params>.
2989  *
2990  * Userspace is free to initialize the metadata devices, hence the superblocks to
2991  * enforce recreation based on the passed in table parameters.
2992  *
2993  */
2994 static int raid_ctr(struct dm_target *ti, unsigned int argc, char **argv)
2995 {
2996 	int r;
2997 	bool resize = false;
2998 	struct raid_type *rt;
2999 	unsigned int num_raid_params, num_raid_devs;
3000 	sector_t sb_array_sectors, rdev_sectors, reshape_sectors;
3001 	struct raid_set *rs = NULL;
3002 	const char *arg;
3003 	struct rs_layout rs_layout;
3004 	struct dm_arg_set as = { argc, argv }, as_nrd;
3005 	struct dm_arg _args[] = {
3006 		{ 0, as.argc, "Cannot understand number of raid parameters" },
3007 		{ 1, 254, "Cannot understand number of raid devices parameters" }
3008 	};
3009 
3010 	arg = dm_shift_arg(&as);
3011 	if (!arg) {
3012 		ti->error = "No arguments";
3013 		return -EINVAL;
3014 	}
3015 
3016 	rt = get_raid_type(arg);
3017 	if (!rt) {
3018 		ti->error = "Unrecognised raid_type";
3019 		return -EINVAL;
3020 	}
3021 
3022 	/* Must have <#raid_params> */
3023 	if (dm_read_arg_group(_args, &as, &num_raid_params, &ti->error))
3024 		return -EINVAL;
3025 
3026 	/* number of raid device tupples <meta_dev data_dev> */
3027 	as_nrd = as;
3028 	dm_consume_args(&as_nrd, num_raid_params);
3029 	_args[1].max = (as_nrd.argc - 1) / 2;
3030 	if (dm_read_arg(_args + 1, &as_nrd, &num_raid_devs, &ti->error))
3031 		return -EINVAL;
3032 
3033 	if (!__within_range(num_raid_devs, 1, MAX_RAID_DEVICES)) {
3034 		ti->error = "Invalid number of supplied raid devices";
3035 		return -EINVAL;
3036 	}
3037 
3038 	rs = raid_set_alloc(ti, rt, num_raid_devs);
3039 	if (IS_ERR(rs))
3040 		return PTR_ERR(rs);
3041 
3042 	r = parse_raid_params(rs, &as, num_raid_params);
3043 	if (r)
3044 		goto bad;
3045 
3046 	r = parse_dev_params(rs, &as);
3047 	if (r)
3048 		goto bad;
3049 
3050 	rs->md.sync_super = super_sync;
3051 
3052 	/*
3053 	 * Calculate ctr requested array and device sizes to allow
3054 	 * for superblock analysis needing device sizes defined.
3055 	 *
3056 	 * Any existing superblock will overwrite the array and device sizes
3057 	 */
3058 	r = rs_set_dev_and_array_sectors(rs, rs->ti->len, false);
3059 	if (r)
3060 		goto bad;
3061 
3062 	/* Memorize just calculated, potentially larger sizes to grow the raid set in preresume */
3063 	rs->array_sectors = rs->md.array_sectors;
3064 	rs->dev_sectors = rs->md.dev_sectors;
3065 
3066 	/*
3067 	 * Backup any new raid set level, layout, ...
3068 	 * requested to be able to compare to superblock
3069 	 * members for conversion decisions.
3070 	 */
3071 	rs_config_backup(rs, &rs_layout);
3072 
3073 	r = analyse_superblocks(ti, rs);
3074 	if (r)
3075 		goto bad;
3076 
3077 	/* All in-core metadata now as of current superblocks after calling analyse_superblocks() */
3078 	sb_array_sectors = rs->md.array_sectors;
3079 	rdev_sectors = __rdev_sectors(rs);
3080 	if (!rdev_sectors) {
3081 		ti->error = "Invalid rdev size";
3082 		r = -EINVAL;
3083 		goto bad;
3084 	}
3085 
3086 
3087 	reshape_sectors = _get_reshape_sectors(rs);
3088 	if (rs->dev_sectors != rdev_sectors) {
3089 		resize = (rs->dev_sectors != rdev_sectors - reshape_sectors);
3090 		if (rs->dev_sectors > rdev_sectors - reshape_sectors)
3091 			set_bit(RT_FLAG_RS_GROW, &rs->runtime_flags);
3092 	}
3093 
3094 	INIT_WORK(&rs->md.event_work, do_table_event);
3095 	ti->private = rs;
3096 	ti->num_flush_bios = 1;
3097 	ti->needs_bio_set_dev = true;
3098 
3099 	/* Restore any requested new layout for conversion decision */
3100 	rs_config_restore(rs, &rs_layout);
3101 
3102 	/*
3103 	 * Now that we have any superblock metadata available,
3104 	 * check for new, recovering, reshaping, to be taken over,
3105 	 * to be reshaped or an existing, unchanged raid set to
3106 	 * run in sequence.
3107 	 */
3108 	if (test_bit(MD_ARRAY_FIRST_USE, &rs->md.flags)) {
3109 		/* A new raid6 set has to be recovered to ensure proper parity and Q-Syndrome */
3110 		if (rs_is_raid6(rs) &&
3111 		    test_bit(__CTR_FLAG_NOSYNC, &rs->ctr_flags)) {
3112 			ti->error = "'nosync' not allowed for new raid6 set";
3113 			r = -EINVAL;
3114 			goto bad;
3115 		}
3116 		rs_setup_recovery(rs, 0);
3117 		set_bit(RT_FLAG_UPDATE_SBS, &rs->runtime_flags);
3118 		rs_set_new(rs);
3119 	} else if (rs_is_recovering(rs)) {
3120 		/* A recovering raid set may be resized */
3121 		goto size_check;
3122 	} else if (rs_is_reshaping(rs)) {
3123 		/* Have to reject size change request during reshape */
3124 		if (resize) {
3125 			ti->error = "Can't resize a reshaping raid set";
3126 			r = -EPERM;
3127 			goto bad;
3128 		}
3129 		/* skip setup rs */
3130 	} else if (rs_takeover_requested(rs)) {
3131 		if (rs_is_reshaping(rs)) {
3132 			ti->error = "Can't takeover a reshaping raid set";
3133 			r = -EPERM;
3134 			goto bad;
3135 		}
3136 
3137 		/* We can't takeover a journaled raid4/5/6 */
3138 		if (test_bit(__CTR_FLAG_JOURNAL_DEV, &rs->ctr_flags)) {
3139 			ti->error = "Can't takeover a journaled raid4/5/6 set";
3140 			r = -EPERM;
3141 			goto bad;
3142 		}
3143 
3144 		/*
3145 		 * If a takeover is needed, userspace sets any additional
3146 		 * devices to rebuild and we can check for a valid request here.
3147 		 *
3148 		 * If acceptable, set the level to the new requested
3149 		 * one, prohibit requesting recovery, allow the raid
3150 		 * set to run and store superblocks during resume.
3151 		 */
3152 		r = rs_check_takeover(rs);
3153 		if (r)
3154 			goto bad;
3155 
3156 		r = rs_setup_takeover(rs);
3157 		if (r)
3158 			goto bad;
3159 
3160 		set_bit(RT_FLAG_UPDATE_SBS, &rs->runtime_flags);
3161 		/* Takeover ain't recovery, so disable recovery */
3162 		rs_setup_recovery(rs, MaxSector);
3163 		rs_set_new(rs);
3164 	} else if (rs_reshape_requested(rs)) {
3165 		/* Only request grow on raid set size extensions, not on reshapes. */
3166 		clear_bit(RT_FLAG_RS_GROW, &rs->runtime_flags);
3167 
3168 		/*
3169 		 * No need to check for 'ongoing' takeover here, because takeover
3170 		 * is an instant operation as oposed to an ongoing reshape.
3171 		 */
3172 
3173 		/* We can't reshape a journaled raid4/5/6 */
3174 		if (test_bit(__CTR_FLAG_JOURNAL_DEV, &rs->ctr_flags)) {
3175 			ti->error = "Can't reshape a journaled raid4/5/6 set";
3176 			r = -EPERM;
3177 			goto bad;
3178 		}
3179 
3180 		/* Out-of-place space has to be available to allow for a reshape unless raid1! */
3181 		if (reshape_sectors || rs_is_raid1(rs)) {
3182 			/*
3183 			 * We can only prepare for a reshape here, because the
3184 			 * raid set needs to run to provide the repective reshape
3185 			 * check functions via its MD personality instance.
3186 			 *
3187 			 * So do the reshape check after md_run() succeeded.
3188 			 */
3189 			r = rs_prepare_reshape(rs);
3190 			if (r)
3191 				goto bad;
3192 
3193 			/* Reshaping ain't recovery, so disable recovery */
3194 			rs_setup_recovery(rs, MaxSector);
3195 		}
3196 		rs_set_cur(rs);
3197 	} else {
3198 size_check:
3199 		/* May not set recovery when a device rebuild is requested */
3200 		if (test_bit(__CTR_FLAG_REBUILD, &rs->ctr_flags)) {
3201 			clear_bit(RT_FLAG_RS_GROW, &rs->runtime_flags);
3202 			set_bit(RT_FLAG_UPDATE_SBS, &rs->runtime_flags);
3203 			rs_setup_recovery(rs, MaxSector);
3204 		} else if (test_bit(RT_FLAG_RS_GROW, &rs->runtime_flags)) {
3205 			/*
3206 			 * Set raid set to current size, i.e. size as of
3207 			 * superblocks to grow to larger size in preresume.
3208 			 */
3209 			r = rs_set_dev_and_array_sectors(rs, sb_array_sectors, false);
3210 			if (r)
3211 				goto bad;
3212 
3213 			rs_setup_recovery(rs, rs->md.recovery_cp < rs->md.dev_sectors ? rs->md.recovery_cp : rs->md.dev_sectors);
3214 		} else {
3215 			/* This is no size change or it is shrinking, update size and record in superblocks */
3216 			r = rs_set_dev_and_array_sectors(rs, rs->ti->len, false);
3217 			if (r)
3218 				goto bad;
3219 
3220 			if (sb_array_sectors > rs->array_sectors)
3221 				set_bit(RT_FLAG_UPDATE_SBS, &rs->runtime_flags);
3222 		}
3223 		rs_set_cur(rs);
3224 	}
3225 
3226 	/* If constructor requested it, change data and new_data offsets */
3227 	r = rs_adjust_data_offsets(rs);
3228 	if (r)
3229 		goto bad;
3230 
3231 	/* Catch any inconclusive reshape superblock content. */
3232 	rs_reset_inconclusive_reshape(rs);
3233 
3234 	/* Start raid set read-only and assumed clean to change in raid_resume() */
3235 	rs->md.ro = 1;
3236 	rs->md.in_sync = 1;
3237 
3238 	/* Keep array frozen until resume. */
3239 	set_bit(MD_RECOVERY_FROZEN, &rs->md.recovery);
3240 
3241 	/* Has to be held on running the array */
3242 	mddev_lock_nointr(&rs->md);
3243 	r = md_run(&rs->md);
3244 	rs->md.in_sync = 0; /* Assume already marked dirty */
3245 	if (r) {
3246 		ti->error = "Failed to run raid array";
3247 		mddev_unlock(&rs->md);
3248 		goto bad;
3249 	}
3250 
3251 	r = md_start(&rs->md);
3252 	if (r) {
3253 		ti->error = "Failed to start raid array";
3254 		mddev_unlock(&rs->md);
3255 		goto bad_md_start;
3256 	}
3257 
3258 	/* If raid4/5/6 journal mode explicitly requested (only possible with journal dev) -> set it */
3259 	if (test_bit(__CTR_FLAG_JOURNAL_MODE, &rs->ctr_flags)) {
3260 		r = r5c_journal_mode_set(&rs->md, rs->journal_dev.mode);
3261 		if (r) {
3262 			ti->error = "Failed to set raid4/5/6 journal mode";
3263 			mddev_unlock(&rs->md);
3264 			goto bad_journal_mode_set;
3265 		}
3266 	}
3267 
3268 	mddev_suspend(&rs->md);
3269 	set_bit(RT_FLAG_RS_SUSPENDED, &rs->runtime_flags);
3270 
3271 	/* Try to adjust the raid4/5/6 stripe cache size to the stripe size */
3272 	if (rs_is_raid456(rs)) {
3273 		r = rs_set_raid456_stripe_cache(rs);
3274 		if (r)
3275 			goto bad_stripe_cache;
3276 	}
3277 
3278 	/* Now do an early reshape check */
3279 	if (test_bit(RT_FLAG_RESHAPE_RS, &rs->runtime_flags)) {
3280 		r = rs_check_reshape(rs);
3281 		if (r)
3282 			goto bad_check_reshape;
3283 
3284 		/* Restore new, ctr requested layout to perform check */
3285 		rs_config_restore(rs, &rs_layout);
3286 
3287 		if (rs->md.pers->start_reshape) {
3288 			r = rs->md.pers->check_reshape(&rs->md);
3289 			if (r) {
3290 				ti->error = "Reshape check failed";
3291 				goto bad_check_reshape;
3292 			}
3293 		}
3294 	}
3295 
3296 	/* Disable/enable discard support on raid set. */
3297 	configure_discard_support(rs);
3298 
3299 	mddev_unlock(&rs->md);
3300 	return 0;
3301 
3302 bad_md_start:
3303 bad_journal_mode_set:
3304 bad_stripe_cache:
3305 bad_check_reshape:
3306 	md_stop(&rs->md);
3307 bad:
3308 	raid_set_free(rs);
3309 
3310 	return r;
3311 }
3312 
3313 static void raid_dtr(struct dm_target *ti)
3314 {
3315 	struct raid_set *rs = ti->private;
3316 
3317 	md_stop(&rs->md);
3318 	raid_set_free(rs);
3319 }
3320 
3321 static int raid_map(struct dm_target *ti, struct bio *bio)
3322 {
3323 	struct raid_set *rs = ti->private;
3324 	struct mddev *mddev = &rs->md;
3325 
3326 	/*
3327 	 * If we're reshaping to add disk(s)), ti->len and
3328 	 * mddev->array_sectors will differ during the process
3329 	 * (ti->len > mddev->array_sectors), so we have to requeue
3330 	 * bios with addresses > mddev->array_sectors here or
3331 	 * there will occur accesses past EOD of the component
3332 	 * data images thus erroring the raid set.
3333 	 */
3334 	if (unlikely(bio_end_sector(bio) > mddev->array_sectors))
3335 		return DM_MAPIO_REQUEUE;
3336 
3337 	md_handle_request(mddev, bio);
3338 
3339 	return DM_MAPIO_SUBMITTED;
3340 }
3341 
3342 /* Return sync state string for @state */
3343 enum sync_state { st_frozen, st_reshape, st_resync, st_check, st_repair, st_recover, st_idle };
3344 static const char *sync_str(enum sync_state state)
3345 {
3346 	/* Has to be in above sync_state order! */
3347 	static const char *sync_strs[] = {
3348 		"frozen",
3349 		"reshape",
3350 		"resync",
3351 		"check",
3352 		"repair",
3353 		"recover",
3354 		"idle"
3355 	};
3356 
3357 	return __within_range(state, 0, ARRAY_SIZE(sync_strs) - 1) ? sync_strs[state] : "undef";
3358 };
3359 
3360 /* Return enum sync_state for @mddev derived from @recovery flags */
3361 static enum sync_state decipher_sync_action(struct mddev *mddev, unsigned long recovery)
3362 {
3363 	if (test_bit(MD_RECOVERY_FROZEN, &recovery))
3364 		return st_frozen;
3365 
3366 	/* The MD sync thread can be done with io or be interrupted but still be running */
3367 	if (!test_bit(MD_RECOVERY_DONE, &recovery) &&
3368 	    (test_bit(MD_RECOVERY_RUNNING, &recovery) ||
3369 	     (!mddev->ro && test_bit(MD_RECOVERY_NEEDED, &recovery)))) {
3370 		if (test_bit(MD_RECOVERY_RESHAPE, &recovery))
3371 			return st_reshape;
3372 
3373 		if (test_bit(MD_RECOVERY_SYNC, &recovery)) {
3374 			if (!test_bit(MD_RECOVERY_REQUESTED, &recovery))
3375 				return st_resync;
3376 			if (test_bit(MD_RECOVERY_CHECK, &recovery))
3377 				return st_check;
3378 			return st_repair;
3379 		}
3380 
3381 		if (test_bit(MD_RECOVERY_RECOVER, &recovery))
3382 			return st_recover;
3383 
3384 		if (mddev->reshape_position != MaxSector)
3385 			return st_reshape;
3386 	}
3387 
3388 	return st_idle;
3389 }
3390 
3391 /*
3392  * Return status string for @rdev
3393  *
3394  * Status characters:
3395  *
3396  *  'D' = Dead/Failed raid set component or raid4/5/6 journal device
3397  *  'a' = Alive but not in-sync raid set component _or_ alive raid4/5/6 'write_back' journal device
3398  *  'A' = Alive and in-sync raid set component _or_ alive raid4/5/6 'write_through' journal device
3399  *  '-' = Non-existing device (i.e. uspace passed '- -' into the ctr)
3400  */
3401 static const char *__raid_dev_status(struct raid_set *rs, struct md_rdev *rdev)
3402 {
3403 	if (!rdev->bdev)
3404 		return "-";
3405 	else if (test_bit(Faulty, &rdev->flags))
3406 		return "D";
3407 	else if (test_bit(Journal, &rdev->flags))
3408 		return (rs->journal_dev.mode == R5C_JOURNAL_MODE_WRITE_THROUGH) ? "A" : "a";
3409 	else if (test_bit(RT_FLAG_RS_RESYNCING, &rs->runtime_flags) ||
3410 		 (!test_bit(RT_FLAG_RS_IN_SYNC, &rs->runtime_flags) &&
3411 		  !test_bit(In_sync, &rdev->flags)))
3412 		return "a";
3413 	else
3414 		return "A";
3415 }
3416 
3417 /* Helper to return resync/reshape progress for @rs and runtime flags for raid set in sync / resynching */
3418 static sector_t rs_get_progress(struct raid_set *rs, unsigned long recovery,
3419 				enum sync_state state, sector_t resync_max_sectors)
3420 {
3421 	sector_t r;
3422 	struct mddev *mddev = &rs->md;
3423 
3424 	clear_bit(RT_FLAG_RS_IN_SYNC, &rs->runtime_flags);
3425 	clear_bit(RT_FLAG_RS_RESYNCING, &rs->runtime_flags);
3426 
3427 	if (rs_is_raid0(rs)) {
3428 		r = resync_max_sectors;
3429 		set_bit(RT_FLAG_RS_IN_SYNC, &rs->runtime_flags);
3430 
3431 	} else {
3432 		if (state == st_idle && !test_bit(MD_RECOVERY_INTR, &recovery))
3433 			r = mddev->recovery_cp;
3434 		else
3435 			r = mddev->curr_resync_completed;
3436 
3437 		if (state == st_idle && r >= resync_max_sectors) {
3438 			/*
3439 			 * Sync complete.
3440 			 */
3441 			/* In case we have finished recovering, the array is in sync. */
3442 			if (test_bit(MD_RECOVERY_RECOVER, &recovery))
3443 				set_bit(RT_FLAG_RS_IN_SYNC, &rs->runtime_flags);
3444 
3445 		} else if (state == st_recover)
3446 			/*
3447 			 * In case we are recovering, the array is not in sync
3448 			 * and health chars should show the recovering legs.
3449 			 *
3450 			 * Already retrieved recovery offset from curr_resync_completed above.
3451 			 */
3452 			;
3453 
3454 		else if (state == st_resync || state == st_reshape)
3455 			/*
3456 			 * If "resync/reshape" is occurring, the raid set
3457 			 * is or may be out of sync hence the health
3458 			 * characters shall be 'a'.
3459 			 */
3460 			set_bit(RT_FLAG_RS_RESYNCING, &rs->runtime_flags);
3461 
3462 		else if (state == st_check || state == st_repair)
3463 			/*
3464 			 * If "check" or "repair" is occurring, the raid set has
3465 			 * undergone an initial sync and the health characters
3466 			 * should not be 'a' anymore.
3467 			 */
3468 			set_bit(RT_FLAG_RS_IN_SYNC, &rs->runtime_flags);
3469 
3470 		else if (test_bit(MD_RECOVERY_NEEDED, &recovery))
3471 			/*
3472 			 * We are idle and recovery is needed, prevent 'A' chars race
3473 			 * caused by components still set to in-sync by constructor.
3474 			 */
3475 			set_bit(RT_FLAG_RS_RESYNCING, &rs->runtime_flags);
3476 
3477 		else {
3478 			/*
3479 			 * We are idle and the raid set may be doing an initial
3480 			 * sync, or it may be rebuilding individual components.
3481 			 * If all the devices are In_sync, then it is the raid set
3482 			 * that is being initialized.
3483 			 */
3484 			struct md_rdev *rdev;
3485 
3486 			set_bit(RT_FLAG_RS_IN_SYNC, &rs->runtime_flags);
3487 			rdev_for_each(rdev, mddev)
3488 				if (!test_bit(Journal, &rdev->flags) &&
3489 				    !test_bit(In_sync, &rdev->flags)) {
3490 					clear_bit(RT_FLAG_RS_IN_SYNC, &rs->runtime_flags);
3491 					break;
3492 				}
3493 		}
3494 	}
3495 
3496 	return min(r, resync_max_sectors);
3497 }
3498 
3499 /* Helper to return @dev name or "-" if !@dev */
3500 static const char *__get_dev_name(struct dm_dev *dev)
3501 {
3502 	return dev ? dev->name : "-";
3503 }
3504 
3505 static void raid_status(struct dm_target *ti, status_type_t type,
3506 			unsigned int status_flags, char *result, unsigned int maxlen)
3507 {
3508 	struct raid_set *rs = ti->private;
3509 	struct mddev *mddev = &rs->md;
3510 	struct r5conf *conf = rs_is_raid456(rs) ? mddev->private : NULL;
3511 	int i, max_nr_stripes = conf ? conf->max_nr_stripes : 0;
3512 	unsigned long recovery;
3513 	unsigned int raid_param_cnt = 1; /* at least 1 for chunksize */
3514 	unsigned int sz = 0;
3515 	unsigned int rebuild_writemostly_count = 0;
3516 	sector_t progress, resync_max_sectors, resync_mismatches;
3517 	enum sync_state state;
3518 	struct raid_type *rt;
3519 
3520 	switch (type) {
3521 	case STATUSTYPE_INFO:
3522 		/* *Should* always succeed */
3523 		rt = get_raid_type_by_ll(mddev->new_level, mddev->new_layout);
3524 		if (!rt)
3525 			return;
3526 
3527 		DMEMIT("%s %d ", rt->name, mddev->raid_disks);
3528 
3529 		/* Access most recent mddev properties for status output */
3530 		smp_rmb();
3531 		/* Get sensible max sectors even if raid set not yet started */
3532 		resync_max_sectors = test_bit(RT_FLAG_RS_PRERESUMED, &rs->runtime_flags) ?
3533 				      mddev->resync_max_sectors : mddev->dev_sectors;
3534 		recovery = rs->md.recovery;
3535 		state = decipher_sync_action(mddev, recovery);
3536 		progress = rs_get_progress(rs, recovery, state, resync_max_sectors);
3537 		resync_mismatches = (mddev->last_sync_action && !strcasecmp(mddev->last_sync_action, "check")) ?
3538 				    atomic64_read(&mddev->resync_mismatches) : 0;
3539 
3540 		/* HM FIXME: do we want another state char for raid0? It shows 'D'/'A'/'-' now */
3541 		for (i = 0; i < rs->raid_disks; i++)
3542 			DMEMIT(__raid_dev_status(rs, &rs->dev[i].rdev));
3543 
3544 		/*
3545 		 * In-sync/Reshape ratio:
3546 		 *  The in-sync ratio shows the progress of:
3547 		 *   - Initializing the raid set
3548 		 *   - Rebuilding a subset of devices of the raid set
3549 		 *  The user can distinguish between the two by referring
3550 		 *  to the status characters.
3551 		 *
3552 		 *  The reshape ratio shows the progress of
3553 		 *  changing the raid layout or the number of
3554 		 *  disks of a raid set
3555 		 */
3556 		DMEMIT(" %llu/%llu", (unsigned long long) progress,
3557 				     (unsigned long long) resync_max_sectors);
3558 
3559 		/*
3560 		 * v1.5.0+:
3561 		 *
3562 		 * Sync action:
3563 		 *   See Documentation/admin-guide/device-mapper/dm-raid.rst for
3564 		 *   information on each of these states.
3565 		 */
3566 		DMEMIT(" %s", sync_str(state));
3567 
3568 		/*
3569 		 * v1.5.0+:
3570 		 *
3571 		 * resync_mismatches/mismatch_cnt
3572 		 *   This field shows the number of discrepancies found when
3573 		 *   performing a "check" of the raid set.
3574 		 */
3575 		DMEMIT(" %llu", (unsigned long long) resync_mismatches);
3576 
3577 		/*
3578 		 * v1.9.0+:
3579 		 *
3580 		 * data_offset (needed for out of space reshaping)
3581 		 *   This field shows the data offset into the data
3582 		 *   image LV where the first stripes data starts.
3583 		 *
3584 		 * We keep data_offset equal on all raid disks of the set,
3585 		 * so retrieving it from the first raid disk is sufficient.
3586 		 */
3587 		DMEMIT(" %llu", (unsigned long long) rs->dev[0].rdev.data_offset);
3588 
3589 		/*
3590 		 * v1.10.0+:
3591 		 */
3592 		DMEMIT(" %s", test_bit(__CTR_FLAG_JOURNAL_DEV, &rs->ctr_flags) ?
3593 			      __raid_dev_status(rs, &rs->journal_dev.rdev) : "-");
3594 		break;
3595 
3596 	case STATUSTYPE_TABLE:
3597 		/* Report the table line string you would use to construct this raid set */
3598 
3599 		/*
3600 		 * Count any rebuild or writemostly argument pairs and subtract the
3601 		 * hweight count being added below of any rebuild and writemostly ctr flags.
3602 		 */
3603 		for (i = 0; i < rs->raid_disks; i++) {
3604 			rebuild_writemostly_count += (test_bit(i, (void *) rs->rebuild_disks) ? 2 : 0) +
3605 						     (test_bit(WriteMostly, &rs->dev[i].rdev.flags) ? 2 : 0);
3606 		}
3607 		rebuild_writemostly_count -= (test_bit(__CTR_FLAG_REBUILD, &rs->ctr_flags) ? 2 : 0) +
3608 					     (test_bit(__CTR_FLAG_WRITE_MOSTLY, &rs->ctr_flags) ? 2 : 0);
3609 		/* Calculate raid parameter count based on ^ rebuild/writemostly argument counts and ctr flags set. */
3610 		raid_param_cnt += rebuild_writemostly_count +
3611 				  hweight32(rs->ctr_flags & CTR_FLAG_OPTIONS_NO_ARGS) +
3612 				  hweight32(rs->ctr_flags & CTR_FLAG_OPTIONS_ONE_ARG) * 2;
3613 		/* Emit table line */
3614 		/* This has to be in the documented order for userspace! */
3615 		DMEMIT("%s %u %u", rs->raid_type->name, raid_param_cnt, mddev->new_chunk_sectors);
3616 		if (test_bit(__CTR_FLAG_SYNC, &rs->ctr_flags))
3617 			DMEMIT(" %s", dm_raid_arg_name_by_flag(CTR_FLAG_SYNC));
3618 		if (test_bit(__CTR_FLAG_NOSYNC, &rs->ctr_flags))
3619 			DMEMIT(" %s", dm_raid_arg_name_by_flag(CTR_FLAG_NOSYNC));
3620 		if (test_bit(__CTR_FLAG_REBUILD, &rs->ctr_flags))
3621 			for (i = 0; i < rs->raid_disks; i++)
3622 				if (test_bit(i, (void *) rs->rebuild_disks))
3623 					DMEMIT(" %s %u", dm_raid_arg_name_by_flag(CTR_FLAG_REBUILD), i);
3624 		if (test_bit(__CTR_FLAG_DAEMON_SLEEP, &rs->ctr_flags))
3625 			DMEMIT(" %s %lu", dm_raid_arg_name_by_flag(CTR_FLAG_DAEMON_SLEEP),
3626 					  mddev->bitmap_info.daemon_sleep);
3627 		if (test_bit(__CTR_FLAG_MIN_RECOVERY_RATE, &rs->ctr_flags))
3628 			DMEMIT(" %s %d", dm_raid_arg_name_by_flag(CTR_FLAG_MIN_RECOVERY_RATE),
3629 					 mddev->sync_speed_min);
3630 		if (test_bit(__CTR_FLAG_MAX_RECOVERY_RATE, &rs->ctr_flags))
3631 			DMEMIT(" %s %d", dm_raid_arg_name_by_flag(CTR_FLAG_MAX_RECOVERY_RATE),
3632 					 mddev->sync_speed_max);
3633 		if (test_bit(__CTR_FLAG_WRITE_MOSTLY, &rs->ctr_flags))
3634 			for (i = 0; i < rs->raid_disks; i++)
3635 				if (test_bit(WriteMostly, &rs->dev[i].rdev.flags))
3636 					DMEMIT(" %s %d", dm_raid_arg_name_by_flag(CTR_FLAG_WRITE_MOSTLY),
3637 					       rs->dev[i].rdev.raid_disk);
3638 		if (test_bit(__CTR_FLAG_MAX_WRITE_BEHIND, &rs->ctr_flags))
3639 			DMEMIT(" %s %lu", dm_raid_arg_name_by_flag(CTR_FLAG_MAX_WRITE_BEHIND),
3640 					  mddev->bitmap_info.max_write_behind);
3641 		if (test_bit(__CTR_FLAG_STRIPE_CACHE, &rs->ctr_flags))
3642 			DMEMIT(" %s %d", dm_raid_arg_name_by_flag(CTR_FLAG_STRIPE_CACHE),
3643 					 max_nr_stripes);
3644 		if (test_bit(__CTR_FLAG_REGION_SIZE, &rs->ctr_flags))
3645 			DMEMIT(" %s %llu", dm_raid_arg_name_by_flag(CTR_FLAG_REGION_SIZE),
3646 					   (unsigned long long) to_sector(mddev->bitmap_info.chunksize));
3647 		if (test_bit(__CTR_FLAG_RAID10_COPIES, &rs->ctr_flags))
3648 			DMEMIT(" %s %d", dm_raid_arg_name_by_flag(CTR_FLAG_RAID10_COPIES),
3649 					 raid10_md_layout_to_copies(mddev->layout));
3650 		if (test_bit(__CTR_FLAG_RAID10_FORMAT, &rs->ctr_flags))
3651 			DMEMIT(" %s %s", dm_raid_arg_name_by_flag(CTR_FLAG_RAID10_FORMAT),
3652 					 raid10_md_layout_to_format(mddev->layout));
3653 		if (test_bit(__CTR_FLAG_DELTA_DISKS, &rs->ctr_flags))
3654 			DMEMIT(" %s %d", dm_raid_arg_name_by_flag(CTR_FLAG_DELTA_DISKS),
3655 					 max(rs->delta_disks, mddev->delta_disks));
3656 		if (test_bit(__CTR_FLAG_DATA_OFFSET, &rs->ctr_flags))
3657 			DMEMIT(" %s %llu", dm_raid_arg_name_by_flag(CTR_FLAG_DATA_OFFSET),
3658 					   (unsigned long long) rs->data_offset);
3659 		if (test_bit(__CTR_FLAG_JOURNAL_DEV, &rs->ctr_flags))
3660 			DMEMIT(" %s %s", dm_raid_arg_name_by_flag(CTR_FLAG_JOURNAL_DEV),
3661 					__get_dev_name(rs->journal_dev.dev));
3662 		if (test_bit(__CTR_FLAG_JOURNAL_MODE, &rs->ctr_flags))
3663 			DMEMIT(" %s %s", dm_raid_arg_name_by_flag(CTR_FLAG_JOURNAL_MODE),
3664 					 md_journal_mode_to_dm_raid(rs->journal_dev.mode));
3665 		DMEMIT(" %d", rs->raid_disks);
3666 		for (i = 0; i < rs->raid_disks; i++)
3667 			DMEMIT(" %s %s", __get_dev_name(rs->dev[i].meta_dev),
3668 					 __get_dev_name(rs->dev[i].data_dev));
3669 		break;
3670 
3671 	case STATUSTYPE_IMA:
3672 		rt = get_raid_type_by_ll(mddev->new_level, mddev->new_layout);
3673 		if (!rt)
3674 			return;
3675 
3676 		DMEMIT_TARGET_NAME_VERSION(ti->type);
3677 		DMEMIT(",raid_type=%s,raid_disks=%d", rt->name, mddev->raid_disks);
3678 
3679 		/* Access most recent mddev properties for status output */
3680 		smp_rmb();
3681 		recovery = rs->md.recovery;
3682 		state = decipher_sync_action(mddev, recovery);
3683 		DMEMIT(",raid_state=%s", sync_str(state));
3684 
3685 		for (i = 0; i < rs->raid_disks; i++) {
3686 			DMEMIT(",raid_device_%d_status=", i);
3687 			DMEMIT(__raid_dev_status(rs, &rs->dev[i].rdev));
3688 		}
3689 
3690 		if (rt_is_raid456(rt)) {
3691 			DMEMIT(",journal_dev_mode=");
3692 			switch (rs->journal_dev.mode) {
3693 			case R5C_JOURNAL_MODE_WRITE_THROUGH:
3694 				DMEMIT("%s",
3695 				       _raid456_journal_mode[R5C_JOURNAL_MODE_WRITE_THROUGH].param);
3696 				break;
3697 			case R5C_JOURNAL_MODE_WRITE_BACK:
3698 				DMEMIT("%s",
3699 				       _raid456_journal_mode[R5C_JOURNAL_MODE_WRITE_BACK].param);
3700 				break;
3701 			default:
3702 				DMEMIT("invalid");
3703 				break;
3704 			}
3705 		}
3706 		DMEMIT(";");
3707 		break;
3708 	}
3709 }
3710 
3711 static int raid_message(struct dm_target *ti, unsigned int argc, char **argv,
3712 			char *result, unsigned int maxlen)
3713 {
3714 	struct raid_set *rs = ti->private;
3715 	struct mddev *mddev = &rs->md;
3716 
3717 	if (!mddev->pers || !mddev->pers->sync_request)
3718 		return -EINVAL;
3719 
3720 	if (!strcasecmp(argv[0], "frozen"))
3721 		set_bit(MD_RECOVERY_FROZEN, &mddev->recovery);
3722 	else
3723 		clear_bit(MD_RECOVERY_FROZEN, &mddev->recovery);
3724 
3725 	if (!strcasecmp(argv[0], "idle") || !strcasecmp(argv[0], "frozen")) {
3726 		if (mddev->sync_thread) {
3727 			set_bit(MD_RECOVERY_INTR, &mddev->recovery);
3728 			md_unregister_thread(&mddev->sync_thread);
3729 			md_reap_sync_thread(mddev);
3730 		}
3731 	} else if (decipher_sync_action(mddev, mddev->recovery) != st_idle)
3732 		return -EBUSY;
3733 	else if (!strcasecmp(argv[0], "resync"))
3734 		; /* MD_RECOVERY_NEEDED set below */
3735 	else if (!strcasecmp(argv[0], "recover"))
3736 		set_bit(MD_RECOVERY_RECOVER, &mddev->recovery);
3737 	else {
3738 		if (!strcasecmp(argv[0], "check")) {
3739 			set_bit(MD_RECOVERY_CHECK, &mddev->recovery);
3740 			set_bit(MD_RECOVERY_REQUESTED, &mddev->recovery);
3741 			set_bit(MD_RECOVERY_SYNC, &mddev->recovery);
3742 		} else if (!strcasecmp(argv[0], "repair")) {
3743 			set_bit(MD_RECOVERY_REQUESTED, &mddev->recovery);
3744 			set_bit(MD_RECOVERY_SYNC, &mddev->recovery);
3745 		} else
3746 			return -EINVAL;
3747 	}
3748 	if (mddev->ro == 2) {
3749 		/* A write to sync_action is enough to justify
3750 		 * canceling read-auto mode
3751 		 */
3752 		mddev->ro = 0;
3753 		if (!mddev->suspended)
3754 			md_wakeup_thread(mddev->sync_thread);
3755 	}
3756 	set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
3757 	if (!mddev->suspended)
3758 		md_wakeup_thread(mddev->thread);
3759 
3760 	return 0;
3761 }
3762 
3763 static int raid_iterate_devices(struct dm_target *ti,
3764 				iterate_devices_callout_fn fn, void *data)
3765 {
3766 	struct raid_set *rs = ti->private;
3767 	unsigned int i;
3768 	int r = 0;
3769 
3770 	for (i = 0; !r && i < rs->raid_disks; i++) {
3771 		if (rs->dev[i].data_dev) {
3772 			r = fn(ti, rs->dev[i].data_dev,
3773 			       0, /* No offset on data devs */
3774 			       rs->md.dev_sectors, data);
3775 		}
3776 	}
3777 
3778 	return r;
3779 }
3780 
3781 static void raid_io_hints(struct dm_target *ti, struct queue_limits *limits)
3782 {
3783 	struct raid_set *rs = ti->private;
3784 	unsigned int chunk_size_bytes = to_bytes(rs->md.chunk_sectors);
3785 
3786 	blk_limits_io_min(limits, chunk_size_bytes);
3787 	blk_limits_io_opt(limits, chunk_size_bytes * mddev_data_stripes(rs));
3788 }
3789 
3790 static void raid_postsuspend(struct dm_target *ti)
3791 {
3792 	struct raid_set *rs = ti->private;
3793 
3794 	if (!test_and_set_bit(RT_FLAG_RS_SUSPENDED, &rs->runtime_flags)) {
3795 		/* Writes have to be stopped before suspending to avoid deadlocks. */
3796 		if (!test_bit(MD_RECOVERY_FROZEN, &rs->md.recovery))
3797 			md_stop_writes(&rs->md);
3798 
3799 		mddev_lock_nointr(&rs->md);
3800 		mddev_suspend(&rs->md);
3801 		mddev_unlock(&rs->md);
3802 	}
3803 }
3804 
3805 static void attempt_restore_of_faulty_devices(struct raid_set *rs)
3806 {
3807 	int i;
3808 	uint64_t cleared_failed_devices[DISKS_ARRAY_ELEMS];
3809 	unsigned long flags;
3810 	bool cleared = false;
3811 	struct dm_raid_superblock *sb;
3812 	struct mddev *mddev = &rs->md;
3813 	struct md_rdev *r;
3814 
3815 	/* RAID personalities have to provide hot add/remove methods or we need to bail out. */
3816 	if (!mddev->pers || !mddev->pers->hot_add_disk || !mddev->pers->hot_remove_disk)
3817 		return;
3818 
3819 	memset(cleared_failed_devices, 0, sizeof(cleared_failed_devices));
3820 
3821 	for (i = 0; i < rs->raid_disks; i++) {
3822 		r = &rs->dev[i].rdev;
3823 		/* HM FIXME: enhance journal device recovery processing */
3824 		if (test_bit(Journal, &r->flags))
3825 			continue;
3826 
3827 		if (test_bit(Faulty, &r->flags) &&
3828 		    r->meta_bdev && !read_disk_sb(r, r->sb_size, true)) {
3829 			DMINFO("Faulty %s device #%d has readable super block."
3830 			       "  Attempting to revive it.",
3831 			       rs->raid_type->name, i);
3832 
3833 			/*
3834 			 * Faulty bit may be set, but sometimes the array can
3835 			 * be suspended before the personalities can respond
3836 			 * by removing the device from the array (i.e. calling
3837 			 * 'hot_remove_disk').	If they haven't yet removed
3838 			 * the failed device, its 'raid_disk' number will be
3839 			 * '>= 0' - meaning we must call this function
3840 			 * ourselves.
3841 			 */
3842 			flags = r->flags;
3843 			clear_bit(In_sync, &r->flags); /* Mandatory for hot remove. */
3844 			if (r->raid_disk >= 0) {
3845 				if (mddev->pers->hot_remove_disk(mddev, r)) {
3846 					/* Failed to revive this device, try next */
3847 					r->flags = flags;
3848 					continue;
3849 				}
3850 			} else
3851 				r->raid_disk = r->saved_raid_disk = i;
3852 
3853 			clear_bit(Faulty, &r->flags);
3854 			clear_bit(WriteErrorSeen, &r->flags);
3855 
3856 			if (mddev->pers->hot_add_disk(mddev, r)) {
3857 				/* Failed to revive this device, try next */
3858 				r->raid_disk = r->saved_raid_disk = -1;
3859 				r->flags = flags;
3860 			} else {
3861 				clear_bit(In_sync, &r->flags);
3862 				r->recovery_offset = 0;
3863 				set_bit(i, (void *) cleared_failed_devices);
3864 				cleared = true;
3865 			}
3866 		}
3867 	}
3868 
3869 	/* If any failed devices could be cleared, update all sbs failed_devices bits */
3870 	if (cleared) {
3871 		uint64_t failed_devices[DISKS_ARRAY_ELEMS];
3872 
3873 		rdev_for_each(r, &rs->md) {
3874 			if (test_bit(Journal, &r->flags))
3875 				continue;
3876 
3877 			sb = page_address(r->sb_page);
3878 			sb_retrieve_failed_devices(sb, failed_devices);
3879 
3880 			for (i = 0; i < DISKS_ARRAY_ELEMS; i++)
3881 				failed_devices[i] &= ~cleared_failed_devices[i];
3882 
3883 			sb_update_failed_devices(sb, failed_devices);
3884 		}
3885 	}
3886 }
3887 
3888 static int __load_dirty_region_bitmap(struct raid_set *rs)
3889 {
3890 	int r = 0;
3891 
3892 	/* Try loading the bitmap unless "raid0", which does not have one */
3893 	if (!rs_is_raid0(rs) &&
3894 	    !test_and_set_bit(RT_FLAG_RS_BITMAP_LOADED, &rs->runtime_flags)) {
3895 		r = md_bitmap_load(&rs->md);
3896 		if (r)
3897 			DMERR("Failed to load bitmap");
3898 	}
3899 
3900 	return r;
3901 }
3902 
3903 /* Enforce updating all superblocks */
3904 static void rs_update_sbs(struct raid_set *rs)
3905 {
3906 	struct mddev *mddev = &rs->md;
3907 	int ro = mddev->ro;
3908 
3909 	set_bit(MD_SB_CHANGE_DEVS, &mddev->sb_flags);
3910 	mddev->ro = 0;
3911 	md_update_sb(mddev, 1);
3912 	mddev->ro = ro;
3913 }
3914 
3915 /*
3916  * Reshape changes raid algorithm of @rs to new one within personality
3917  * (e.g. raid6_zr -> raid6_nc), changes stripe size, adds/removes
3918  * disks from a raid set thus growing/shrinking it or resizes the set
3919  *
3920  * Call mddev_lock_nointr() before!
3921  */
3922 static int rs_start_reshape(struct raid_set *rs)
3923 {
3924 	int r;
3925 	struct mddev *mddev = &rs->md;
3926 	struct md_personality *pers = mddev->pers;
3927 
3928 	/* Don't allow the sync thread to work until the table gets reloaded. */
3929 	set_bit(MD_RECOVERY_WAIT, &mddev->recovery);
3930 
3931 	r = rs_setup_reshape(rs);
3932 	if (r)
3933 		return r;
3934 
3935 	/*
3936 	 * Check any reshape constraints enforced by the personalility
3937 	 *
3938 	 * May as well already kick the reshape off so that * pers->start_reshape() becomes optional.
3939 	 */
3940 	r = pers->check_reshape(mddev);
3941 	if (r) {
3942 		rs->ti->error = "pers->check_reshape() failed";
3943 		return r;
3944 	}
3945 
3946 	/*
3947 	 * Personality may not provide start reshape method in which
3948 	 * case check_reshape above has already covered everything
3949 	 */
3950 	if (pers->start_reshape) {
3951 		r = pers->start_reshape(mddev);
3952 		if (r) {
3953 			rs->ti->error = "pers->start_reshape() failed";
3954 			return r;
3955 		}
3956 	}
3957 
3958 	/*
3959 	 * Now reshape got set up, update superblocks to
3960 	 * reflect the fact so that a table reload will
3961 	 * access proper superblock content in the ctr.
3962 	 */
3963 	rs_update_sbs(rs);
3964 
3965 	return 0;
3966 }
3967 
3968 static int raid_preresume(struct dm_target *ti)
3969 {
3970 	int r;
3971 	struct raid_set *rs = ti->private;
3972 	struct mddev *mddev = &rs->md;
3973 
3974 	/* This is a resume after a suspend of the set -> it's already started. */
3975 	if (test_and_set_bit(RT_FLAG_RS_PRERESUMED, &rs->runtime_flags))
3976 		return 0;
3977 
3978 	/*
3979 	 * The superblocks need to be updated on disk if the
3980 	 * array is new or new devices got added (thus zeroed
3981 	 * out by userspace) or __load_dirty_region_bitmap
3982 	 * will overwrite them in core with old data or fail.
3983 	 */
3984 	if (test_bit(RT_FLAG_UPDATE_SBS, &rs->runtime_flags))
3985 		rs_update_sbs(rs);
3986 
3987 	/* Load the bitmap from disk unless raid0 */
3988 	r = __load_dirty_region_bitmap(rs);
3989 	if (r)
3990 		return r;
3991 
3992 	/* We are extending the raid set size, adjust mddev/md_rdev sizes and set capacity. */
3993 	if (test_bit(RT_FLAG_RS_GROW, &rs->runtime_flags)) {
3994 		mddev->array_sectors = rs->array_sectors;
3995 		mddev->dev_sectors = rs->dev_sectors;
3996 		rs_set_rdev_sectors(rs);
3997 		rs_set_capacity(rs);
3998 	}
3999 
4000 	/* Resize bitmap to adjust to changed region size (aka MD bitmap chunksize) or grown device size */
4001 	if (test_bit(RT_FLAG_RS_BITMAP_LOADED, &rs->runtime_flags) && mddev->bitmap &&
4002 	    (test_bit(RT_FLAG_RS_GROW, &rs->runtime_flags) ||
4003 	     (rs->requested_bitmap_chunk_sectors &&
4004 	       mddev->bitmap_info.chunksize != to_bytes(rs->requested_bitmap_chunk_sectors)))) {
4005 		int chunksize = to_bytes(rs->requested_bitmap_chunk_sectors) ?: mddev->bitmap_info.chunksize;
4006 
4007 		r = md_bitmap_resize(mddev->bitmap, mddev->dev_sectors, chunksize, 0);
4008 		if (r)
4009 			DMERR("Failed to resize bitmap");
4010 	}
4011 
4012 	/* Check for any resize/reshape on @rs and adjust/initiate */
4013 	/* Be prepared for mddev_resume() in raid_resume() */
4014 	set_bit(MD_RECOVERY_FROZEN, &mddev->recovery);
4015 	if (mddev->recovery_cp && mddev->recovery_cp < MaxSector) {
4016 		set_bit(MD_RECOVERY_REQUESTED, &mddev->recovery);
4017 		mddev->resync_min = mddev->recovery_cp;
4018 		if (test_bit(RT_FLAG_RS_GROW, &rs->runtime_flags))
4019 			mddev->resync_max_sectors = mddev->dev_sectors;
4020 	}
4021 
4022 	/* Check for any reshape request unless new raid set */
4023 	if (test_bit(RT_FLAG_RESHAPE_RS, &rs->runtime_flags)) {
4024 		/* Initiate a reshape. */
4025 		rs_set_rdev_sectors(rs);
4026 		mddev_lock_nointr(mddev);
4027 		r = rs_start_reshape(rs);
4028 		mddev_unlock(mddev);
4029 		if (r)
4030 			DMWARN("Failed to check/start reshape, continuing without change");
4031 		r = 0;
4032 	}
4033 
4034 	return r;
4035 }
4036 
4037 static void raid_resume(struct dm_target *ti)
4038 {
4039 	struct raid_set *rs = ti->private;
4040 	struct mddev *mddev = &rs->md;
4041 
4042 	if (test_and_set_bit(RT_FLAG_RS_RESUMED, &rs->runtime_flags)) {
4043 		/*
4044 		 * A secondary resume while the device is active.
4045 		 * Take this opportunity to check whether any failed
4046 		 * devices are reachable again.
4047 		 */
4048 		attempt_restore_of_faulty_devices(rs);
4049 	}
4050 
4051 	if (test_and_clear_bit(RT_FLAG_RS_SUSPENDED, &rs->runtime_flags)) {
4052 		/* Only reduce raid set size before running a disk removing reshape. */
4053 		if (mddev->delta_disks < 0)
4054 			rs_set_capacity(rs);
4055 
4056 		mddev_lock_nointr(mddev);
4057 		clear_bit(MD_RECOVERY_FROZEN, &mddev->recovery);
4058 		mddev->ro = 0;
4059 		mddev->in_sync = 0;
4060 		mddev_resume(mddev);
4061 		mddev_unlock(mddev);
4062 	}
4063 }
4064 
4065 static struct target_type raid_target = {
4066 	.name = "raid",
4067 	.version = {1, 15, 1},
4068 	.module = THIS_MODULE,
4069 	.ctr = raid_ctr,
4070 	.dtr = raid_dtr,
4071 	.map = raid_map,
4072 	.status = raid_status,
4073 	.message = raid_message,
4074 	.iterate_devices = raid_iterate_devices,
4075 	.io_hints = raid_io_hints,
4076 	.postsuspend = raid_postsuspend,
4077 	.preresume = raid_preresume,
4078 	.resume = raid_resume,
4079 };
4080 module_dm(raid);
4081 
4082 module_param(devices_handle_discard_safely, bool, 0644);
4083 MODULE_PARM_DESC(devices_handle_discard_safely,
4084 		 "Set to Y if all devices in each array reliably return zeroes on reads from discarded regions");
4085 
4086 MODULE_DESCRIPTION(DM_NAME " raid0/1/10/4/5/6 target");
4087 MODULE_ALIAS("dm-raid0");
4088 MODULE_ALIAS("dm-raid1");
4089 MODULE_ALIAS("dm-raid10");
4090 MODULE_ALIAS("dm-raid4");
4091 MODULE_ALIAS("dm-raid5");
4092 MODULE_ALIAS("dm-raid6");
4093 MODULE_AUTHOR("Neil Brown <dm-devel@redhat.com>");
4094 MODULE_AUTHOR("Heinz Mauelshagen <dm-devel@redhat.com>");
4095 MODULE_LICENSE("GPL");
4096