xref: /linux/drivers/md/dm-raid.c (revision bb5b94f5bbe75470912b70fb08880fc5273aa62d)
1 /*
2  * Copyright (C) 2010-2011 Neil Brown
3  * Copyright (C) 2010-2018 Red Hat, Inc. All rights reserved.
4  *
5  * This file is released under the GPL.
6  */
7 
8 #include <linux/slab.h>
9 #include <linux/module.h>
10 
11 #include "md.h"
12 #include "raid1.h"
13 #include "raid5.h"
14 #include "raid10.h"
15 #include "md-bitmap.h"
16 
17 #include <linux/device-mapper.h>
18 
19 #define DM_MSG_PREFIX "raid"
20 #define	MAX_RAID_DEVICES	253 /* md-raid kernel limit */
21 
22 /*
23  * Minimum sectors of free reshape space per raid device
24  */
25 #define	MIN_FREE_RESHAPE_SPACE to_sector(4*4096)
26 
27 /*
28  * Minimum journal space 4 MiB in sectors.
29  */
30 #define	MIN_RAID456_JOURNAL_SPACE (4*2048)
31 
32 static bool devices_handle_discard_safely = false;
33 
34 /*
35  * The following flags are used by dm-raid.c to set up the array state.
36  * They must be cleared before md_run is called.
37  */
38 #define FirstUse 10		/* rdev flag */
39 
40 struct raid_dev {
41 	/*
42 	 * Two DM devices, one to hold metadata and one to hold the
43 	 * actual data/parity.	The reason for this is to not confuse
44 	 * ti->len and give more flexibility in altering size and
45 	 * characteristics.
46 	 *
47 	 * While it is possible for this device to be associated
48 	 * with a different physical device than the data_dev, it
49 	 * is intended for it to be the same.
50 	 *    |--------- Physical Device ---------|
51 	 *    |- meta_dev -|------ data_dev ------|
52 	 */
53 	struct dm_dev *meta_dev;
54 	struct dm_dev *data_dev;
55 	struct md_rdev rdev;
56 };
57 
58 /*
59  * Bits for establishing rs->ctr_flags
60  *
61  * 1 = no flag value
62  * 2 = flag with value
63  */
64 #define __CTR_FLAG_SYNC			0  /* 1 */ /* Not with raid0! */
65 #define __CTR_FLAG_NOSYNC		1  /* 1 */ /* Not with raid0! */
66 #define __CTR_FLAG_REBUILD		2  /* 2 */ /* Not with raid0! */
67 #define __CTR_FLAG_DAEMON_SLEEP		3  /* 2 */ /* Not with raid0! */
68 #define __CTR_FLAG_MIN_RECOVERY_RATE	4  /* 2 */ /* Not with raid0! */
69 #define __CTR_FLAG_MAX_RECOVERY_RATE	5  /* 2 */ /* Not with raid0! */
70 #define __CTR_FLAG_MAX_WRITE_BEHIND	6  /* 2 */ /* Only with raid1! */
71 #define __CTR_FLAG_WRITE_MOSTLY		7  /* 2 */ /* Only with raid1! */
72 #define __CTR_FLAG_STRIPE_CACHE		8  /* 2 */ /* Only with raid4/5/6! */
73 #define __CTR_FLAG_REGION_SIZE		9  /* 2 */ /* Not with raid0! */
74 #define __CTR_FLAG_RAID10_COPIES	10 /* 2 */ /* Only with raid10 */
75 #define __CTR_FLAG_RAID10_FORMAT	11 /* 2 */ /* Only with raid10 */
76 /* New for v1.9.0 */
77 #define __CTR_FLAG_DELTA_DISKS		12 /* 2 */ /* Only with reshapable raid1/4/5/6/10! */
78 #define __CTR_FLAG_DATA_OFFSET		13 /* 2 */ /* Only with reshapable raid4/5/6/10! */
79 #define __CTR_FLAG_RAID10_USE_NEAR_SETS 14 /* 2 */ /* Only with raid10! */
80 
81 /* New for v1.10.0 */
82 #define __CTR_FLAG_JOURNAL_DEV		15 /* 2 */ /* Only with raid4/5/6 (journal device)! */
83 
84 /* New for v1.11.1 */
85 #define __CTR_FLAG_JOURNAL_MODE		16 /* 2 */ /* Only with raid4/5/6 (journal mode)! */
86 
87 /*
88  * Flags for rs->ctr_flags field.
89  */
90 #define CTR_FLAG_SYNC			(1 << __CTR_FLAG_SYNC)
91 #define CTR_FLAG_NOSYNC			(1 << __CTR_FLAG_NOSYNC)
92 #define CTR_FLAG_REBUILD		(1 << __CTR_FLAG_REBUILD)
93 #define CTR_FLAG_DAEMON_SLEEP		(1 << __CTR_FLAG_DAEMON_SLEEP)
94 #define CTR_FLAG_MIN_RECOVERY_RATE	(1 << __CTR_FLAG_MIN_RECOVERY_RATE)
95 #define CTR_FLAG_MAX_RECOVERY_RATE	(1 << __CTR_FLAG_MAX_RECOVERY_RATE)
96 #define CTR_FLAG_MAX_WRITE_BEHIND	(1 << __CTR_FLAG_MAX_WRITE_BEHIND)
97 #define CTR_FLAG_WRITE_MOSTLY		(1 << __CTR_FLAG_WRITE_MOSTLY)
98 #define CTR_FLAG_STRIPE_CACHE		(1 << __CTR_FLAG_STRIPE_CACHE)
99 #define CTR_FLAG_REGION_SIZE		(1 << __CTR_FLAG_REGION_SIZE)
100 #define CTR_FLAG_RAID10_COPIES		(1 << __CTR_FLAG_RAID10_COPIES)
101 #define CTR_FLAG_RAID10_FORMAT		(1 << __CTR_FLAG_RAID10_FORMAT)
102 #define CTR_FLAG_DELTA_DISKS		(1 << __CTR_FLAG_DELTA_DISKS)
103 #define CTR_FLAG_DATA_OFFSET		(1 << __CTR_FLAG_DATA_OFFSET)
104 #define CTR_FLAG_RAID10_USE_NEAR_SETS	(1 << __CTR_FLAG_RAID10_USE_NEAR_SETS)
105 #define CTR_FLAG_JOURNAL_DEV		(1 << __CTR_FLAG_JOURNAL_DEV)
106 #define CTR_FLAG_JOURNAL_MODE		(1 << __CTR_FLAG_JOURNAL_MODE)
107 
108 /*
109  * Definitions of various constructor flags to
110  * be used in checks of valid / invalid flags
111  * per raid level.
112  */
113 /* Define all any sync flags */
114 #define	CTR_FLAGS_ANY_SYNC		(CTR_FLAG_SYNC | CTR_FLAG_NOSYNC)
115 
116 /* Define flags for options without argument (e.g. 'nosync') */
117 #define	CTR_FLAG_OPTIONS_NO_ARGS	(CTR_FLAGS_ANY_SYNC | \
118 					 CTR_FLAG_RAID10_USE_NEAR_SETS)
119 
120 /* Define flags for options with one argument (e.g. 'delta_disks +2') */
121 #define CTR_FLAG_OPTIONS_ONE_ARG (CTR_FLAG_REBUILD | \
122 				  CTR_FLAG_WRITE_MOSTLY | \
123 				  CTR_FLAG_DAEMON_SLEEP | \
124 				  CTR_FLAG_MIN_RECOVERY_RATE | \
125 				  CTR_FLAG_MAX_RECOVERY_RATE | \
126 				  CTR_FLAG_MAX_WRITE_BEHIND | \
127 				  CTR_FLAG_STRIPE_CACHE | \
128 				  CTR_FLAG_REGION_SIZE | \
129 				  CTR_FLAG_RAID10_COPIES | \
130 				  CTR_FLAG_RAID10_FORMAT | \
131 				  CTR_FLAG_DELTA_DISKS | \
132 				  CTR_FLAG_DATA_OFFSET | \
133 				  CTR_FLAG_JOURNAL_DEV | \
134 				  CTR_FLAG_JOURNAL_MODE)
135 
136 /* Valid options definitions per raid level... */
137 
138 /* "raid0" does only accept data offset */
139 #define RAID0_VALID_FLAGS	(CTR_FLAG_DATA_OFFSET)
140 
141 /* "raid1" does not accept stripe cache, data offset, delta_disks or any raid10 options */
142 #define RAID1_VALID_FLAGS	(CTR_FLAGS_ANY_SYNC | \
143 				 CTR_FLAG_REBUILD | \
144 				 CTR_FLAG_WRITE_MOSTLY | \
145 				 CTR_FLAG_DAEMON_SLEEP | \
146 				 CTR_FLAG_MIN_RECOVERY_RATE | \
147 				 CTR_FLAG_MAX_RECOVERY_RATE | \
148 				 CTR_FLAG_MAX_WRITE_BEHIND | \
149 				 CTR_FLAG_REGION_SIZE | \
150 				 CTR_FLAG_DELTA_DISKS | \
151 				 CTR_FLAG_DATA_OFFSET)
152 
153 /* "raid10" does not accept any raid1 or stripe cache options */
154 #define RAID10_VALID_FLAGS	(CTR_FLAGS_ANY_SYNC | \
155 				 CTR_FLAG_REBUILD | \
156 				 CTR_FLAG_DAEMON_SLEEP | \
157 				 CTR_FLAG_MIN_RECOVERY_RATE | \
158 				 CTR_FLAG_MAX_RECOVERY_RATE | \
159 				 CTR_FLAG_REGION_SIZE | \
160 				 CTR_FLAG_RAID10_COPIES | \
161 				 CTR_FLAG_RAID10_FORMAT | \
162 				 CTR_FLAG_DELTA_DISKS | \
163 				 CTR_FLAG_DATA_OFFSET | \
164 				 CTR_FLAG_RAID10_USE_NEAR_SETS)
165 
166 /*
167  * "raid4/5/6" do not accept any raid1 or raid10 specific options
168  *
169  * "raid6" does not accept "nosync", because it is not guaranteed
170  * that both parity and q-syndrome are being written properly with
171  * any writes
172  */
173 #define RAID45_VALID_FLAGS	(CTR_FLAGS_ANY_SYNC | \
174 				 CTR_FLAG_REBUILD | \
175 				 CTR_FLAG_DAEMON_SLEEP | \
176 				 CTR_FLAG_MIN_RECOVERY_RATE | \
177 				 CTR_FLAG_MAX_RECOVERY_RATE | \
178 				 CTR_FLAG_STRIPE_CACHE | \
179 				 CTR_FLAG_REGION_SIZE | \
180 				 CTR_FLAG_DELTA_DISKS | \
181 				 CTR_FLAG_DATA_OFFSET | \
182 				 CTR_FLAG_JOURNAL_DEV | \
183 				 CTR_FLAG_JOURNAL_MODE)
184 
185 #define RAID6_VALID_FLAGS	(CTR_FLAG_SYNC | \
186 				 CTR_FLAG_REBUILD | \
187 				 CTR_FLAG_DAEMON_SLEEP | \
188 				 CTR_FLAG_MIN_RECOVERY_RATE | \
189 				 CTR_FLAG_MAX_RECOVERY_RATE | \
190 				 CTR_FLAG_STRIPE_CACHE | \
191 				 CTR_FLAG_REGION_SIZE | \
192 				 CTR_FLAG_DELTA_DISKS | \
193 				 CTR_FLAG_DATA_OFFSET | \
194 				 CTR_FLAG_JOURNAL_DEV | \
195 				 CTR_FLAG_JOURNAL_MODE)
196 /* ...valid options definitions per raid level */
197 
198 /*
199  * Flags for rs->runtime_flags field
200  * (RT_FLAG prefix meaning "runtime flag")
201  *
202  * These are all internal and used to define runtime state,
203  * e.g. to prevent another resume from preresume processing
204  * the raid set all over again.
205  */
206 #define RT_FLAG_RS_PRERESUMED		0
207 #define RT_FLAG_RS_RESUMED		1
208 #define RT_FLAG_RS_BITMAP_LOADED	2
209 #define RT_FLAG_UPDATE_SBS		3
210 #define RT_FLAG_RESHAPE_RS		4
211 #define RT_FLAG_RS_SUSPENDED		5
212 #define RT_FLAG_RS_IN_SYNC		6
213 #define RT_FLAG_RS_RESYNCING		7
214 #define RT_FLAG_RS_GROW			8
215 
216 /* Array elements of 64 bit needed for rebuild/failed disk bits */
217 #define DISKS_ARRAY_ELEMS ((MAX_RAID_DEVICES + (sizeof(uint64_t) * 8 - 1)) / sizeof(uint64_t) / 8)
218 
219 /*
220  * raid set level, layout and chunk sectors backup/restore
221  */
222 struct rs_layout {
223 	int new_level;
224 	int new_layout;
225 	int new_chunk_sectors;
226 };
227 
228 struct raid_set {
229 	struct dm_target *ti;
230 
231 	uint32_t stripe_cache_entries;
232 	unsigned long ctr_flags;
233 	unsigned long runtime_flags;
234 
235 	uint64_t rebuild_disks[DISKS_ARRAY_ELEMS];
236 
237 	int raid_disks;
238 	int delta_disks;
239 	int data_offset;
240 	int raid10_copies;
241 	int requested_bitmap_chunk_sectors;
242 
243 	struct mddev md;
244 	struct raid_type *raid_type;
245 
246 	sector_t array_sectors;
247 	sector_t dev_sectors;
248 
249 	/* Optional raid4/5/6 journal device */
250 	struct journal_dev {
251 		struct dm_dev *dev;
252 		struct md_rdev rdev;
253 		int mode;
254 	} journal_dev;
255 
256 	struct raid_dev dev[];
257 };
258 
259 static void rs_config_backup(struct raid_set *rs, struct rs_layout *l)
260 {
261 	struct mddev *mddev = &rs->md;
262 
263 	l->new_level = mddev->new_level;
264 	l->new_layout = mddev->new_layout;
265 	l->new_chunk_sectors = mddev->new_chunk_sectors;
266 }
267 
268 static void rs_config_restore(struct raid_set *rs, struct rs_layout *l)
269 {
270 	struct mddev *mddev = &rs->md;
271 
272 	mddev->new_level = l->new_level;
273 	mddev->new_layout = l->new_layout;
274 	mddev->new_chunk_sectors = l->new_chunk_sectors;
275 }
276 
277 /* raid10 algorithms (i.e. formats) */
278 #define	ALGORITHM_RAID10_DEFAULT	0
279 #define	ALGORITHM_RAID10_NEAR		1
280 #define	ALGORITHM_RAID10_OFFSET		2
281 #define	ALGORITHM_RAID10_FAR		3
282 
283 /* Supported raid types and properties. */
284 static struct raid_type {
285 	const char *name;		/* RAID algorithm. */
286 	const char *descr;		/* Descriptor text for logging. */
287 	const unsigned int parity_devs;	/* # of parity devices. */
288 	const unsigned int minimal_devs;/* minimal # of devices in set. */
289 	const unsigned int level;	/* RAID level. */
290 	const unsigned int algorithm;	/* RAID algorithm. */
291 } raid_types[] = {
292 	{"raid0",	  "raid0 (striping)",			    0, 2, 0,  0 /* NONE */},
293 	{"raid1",	  "raid1 (mirroring)",			    0, 2, 1,  0 /* NONE */},
294 	{"raid10_far",	  "raid10 far (striped mirrors)",	    0, 2, 10, ALGORITHM_RAID10_FAR},
295 	{"raid10_offset", "raid10 offset (striped mirrors)",	    0, 2, 10, ALGORITHM_RAID10_OFFSET},
296 	{"raid10_near",	  "raid10 near (striped mirrors)",	    0, 2, 10, ALGORITHM_RAID10_NEAR},
297 	{"raid10",	  "raid10 (striped mirrors)",		    0, 2, 10, ALGORITHM_RAID10_DEFAULT},
298 	{"raid4",	  "raid4 (dedicated first parity disk)",    1, 2, 5,  ALGORITHM_PARITY_0}, /* raid4 layout = raid5_0 */
299 	{"raid5_n",	  "raid5 (dedicated last parity disk)",	    1, 2, 5,  ALGORITHM_PARITY_N},
300 	{"raid5_ls",	  "raid5 (left symmetric)",		    1, 2, 5,  ALGORITHM_LEFT_SYMMETRIC},
301 	{"raid5_rs",	  "raid5 (right symmetric)",		    1, 2, 5,  ALGORITHM_RIGHT_SYMMETRIC},
302 	{"raid5_la",	  "raid5 (left asymmetric)",		    1, 2, 5,  ALGORITHM_LEFT_ASYMMETRIC},
303 	{"raid5_ra",	  "raid5 (right asymmetric)",		    1, 2, 5,  ALGORITHM_RIGHT_ASYMMETRIC},
304 	{"raid6_zr",	  "raid6 (zero restart)",		    2, 4, 6,  ALGORITHM_ROTATING_ZERO_RESTART},
305 	{"raid6_nr",	  "raid6 (N restart)",			    2, 4, 6,  ALGORITHM_ROTATING_N_RESTART},
306 	{"raid6_nc",	  "raid6 (N continue)",			    2, 4, 6,  ALGORITHM_ROTATING_N_CONTINUE},
307 	{"raid6_n_6",	  "raid6 (dedicated parity/Q n/6)",	    2, 4, 6,  ALGORITHM_PARITY_N_6},
308 	{"raid6_ls_6",	  "raid6 (left symmetric dedicated Q 6)",   2, 4, 6,  ALGORITHM_LEFT_SYMMETRIC_6},
309 	{"raid6_rs_6",	  "raid6 (right symmetric dedicated Q 6)",  2, 4, 6,  ALGORITHM_RIGHT_SYMMETRIC_6},
310 	{"raid6_la_6",	  "raid6 (left asymmetric dedicated Q 6)",  2, 4, 6,  ALGORITHM_LEFT_ASYMMETRIC_6},
311 	{"raid6_ra_6",	  "raid6 (right asymmetric dedicated Q 6)", 2, 4, 6,  ALGORITHM_RIGHT_ASYMMETRIC_6}
312 };
313 
314 /* True, if @v is in inclusive range [@min, @max] */
315 static bool __within_range(long v, long min, long max)
316 {
317 	return v >= min && v <= max;
318 }
319 
320 /* All table line arguments are defined here */
321 static struct arg_name_flag {
322 	const unsigned long flag;
323 	const char *name;
324 } __arg_name_flags[] = {
325 	{ CTR_FLAG_SYNC, "sync"},
326 	{ CTR_FLAG_NOSYNC, "nosync"},
327 	{ CTR_FLAG_REBUILD, "rebuild"},
328 	{ CTR_FLAG_DAEMON_SLEEP, "daemon_sleep"},
329 	{ CTR_FLAG_MIN_RECOVERY_RATE, "min_recovery_rate"},
330 	{ CTR_FLAG_MAX_RECOVERY_RATE, "max_recovery_rate"},
331 	{ CTR_FLAG_MAX_WRITE_BEHIND, "max_write_behind"},
332 	{ CTR_FLAG_WRITE_MOSTLY, "write_mostly"},
333 	{ CTR_FLAG_STRIPE_CACHE, "stripe_cache"},
334 	{ CTR_FLAG_REGION_SIZE, "region_size"},
335 	{ CTR_FLAG_RAID10_COPIES, "raid10_copies"},
336 	{ CTR_FLAG_RAID10_FORMAT, "raid10_format"},
337 	{ CTR_FLAG_DATA_OFFSET, "data_offset"},
338 	{ CTR_FLAG_DELTA_DISKS, "delta_disks"},
339 	{ CTR_FLAG_RAID10_USE_NEAR_SETS, "raid10_use_near_sets"},
340 	{ CTR_FLAG_JOURNAL_DEV, "journal_dev" },
341 	{ CTR_FLAG_JOURNAL_MODE, "journal_mode" },
342 };
343 
344 /* Return argument name string for given @flag */
345 static const char *dm_raid_arg_name_by_flag(const uint32_t flag)
346 {
347 	if (hweight32(flag) == 1) {
348 		struct arg_name_flag *anf = __arg_name_flags + ARRAY_SIZE(__arg_name_flags);
349 
350 		while (anf-- > __arg_name_flags)
351 			if (flag & anf->flag)
352 				return anf->name;
353 
354 	} else
355 		DMERR("%s called with more than one flag!", __func__);
356 
357 	return NULL;
358 }
359 
360 /* Define correlation of raid456 journal cache modes and dm-raid target line parameters */
361 static struct {
362 	const int mode;
363 	const char *param;
364 } _raid456_journal_mode[] = {
365 	{ R5C_JOURNAL_MODE_WRITE_THROUGH , "writethrough" },
366 	{ R5C_JOURNAL_MODE_WRITE_BACK    , "writeback" }
367 };
368 
369 /* Return MD raid4/5/6 journal mode for dm @journal_mode one */
370 static int dm_raid_journal_mode_to_md(const char *mode)
371 {
372 	int m = ARRAY_SIZE(_raid456_journal_mode);
373 
374 	while (m--)
375 		if (!strcasecmp(mode, _raid456_journal_mode[m].param))
376 			return _raid456_journal_mode[m].mode;
377 
378 	return -EINVAL;
379 }
380 
381 /* Return dm-raid raid4/5/6 journal mode string for @mode */
382 static const char *md_journal_mode_to_dm_raid(const int mode)
383 {
384 	int m = ARRAY_SIZE(_raid456_journal_mode);
385 
386 	while (m--)
387 		if (mode == _raid456_journal_mode[m].mode)
388 			return _raid456_journal_mode[m].param;
389 
390 	return "unknown";
391 }
392 
393 /*
394  * Bool helpers to test for various raid levels of a raid set.
395  * It's level as reported by the superblock rather than
396  * the requested raid_type passed to the constructor.
397  */
398 /* Return true, if raid set in @rs is raid0 */
399 static bool rs_is_raid0(struct raid_set *rs)
400 {
401 	return !rs->md.level;
402 }
403 
404 /* Return true, if raid set in @rs is raid1 */
405 static bool rs_is_raid1(struct raid_set *rs)
406 {
407 	return rs->md.level == 1;
408 }
409 
410 /* Return true, if raid set in @rs is raid10 */
411 static bool rs_is_raid10(struct raid_set *rs)
412 {
413 	return rs->md.level == 10;
414 }
415 
416 /* Return true, if raid set in @rs is level 6 */
417 static bool rs_is_raid6(struct raid_set *rs)
418 {
419 	return rs->md.level == 6;
420 }
421 
422 /* Return true, if raid set in @rs is level 4, 5 or 6 */
423 static bool rs_is_raid456(struct raid_set *rs)
424 {
425 	return __within_range(rs->md.level, 4, 6);
426 }
427 
428 /* Return true, if raid set in @rs is reshapable */
429 static bool __is_raid10_far(int layout);
430 static bool rs_is_reshapable(struct raid_set *rs)
431 {
432 	return rs_is_raid456(rs) ||
433 	       (rs_is_raid10(rs) && !__is_raid10_far(rs->md.new_layout));
434 }
435 
436 /* Return true, if raid set in @rs is recovering */
437 static bool rs_is_recovering(struct raid_set *rs)
438 {
439 	return rs->md.recovery_cp < rs->md.dev_sectors;
440 }
441 
442 /* Return true, if raid set in @rs is reshaping */
443 static bool rs_is_reshaping(struct raid_set *rs)
444 {
445 	return rs->md.reshape_position != MaxSector;
446 }
447 
448 /*
449  * bool helpers to test for various raid levels of a raid type @rt
450  */
451 
452 /* Return true, if raid type in @rt is raid0 */
453 static bool rt_is_raid0(struct raid_type *rt)
454 {
455 	return !rt->level;
456 }
457 
458 /* Return true, if raid type in @rt is raid1 */
459 static bool rt_is_raid1(struct raid_type *rt)
460 {
461 	return rt->level == 1;
462 }
463 
464 /* Return true, if raid type in @rt is raid10 */
465 static bool rt_is_raid10(struct raid_type *rt)
466 {
467 	return rt->level == 10;
468 }
469 
470 /* Return true, if raid type in @rt is raid4/5 */
471 static bool rt_is_raid45(struct raid_type *rt)
472 {
473 	return __within_range(rt->level, 4, 5);
474 }
475 
476 /* Return true, if raid type in @rt is raid6 */
477 static bool rt_is_raid6(struct raid_type *rt)
478 {
479 	return rt->level == 6;
480 }
481 
482 /* Return true, if raid type in @rt is raid4/5/6 */
483 static bool rt_is_raid456(struct raid_type *rt)
484 {
485 	return __within_range(rt->level, 4, 6);
486 }
487 /* END: raid level bools */
488 
489 /* Return valid ctr flags for the raid level of @rs */
490 static unsigned long __valid_flags(struct raid_set *rs)
491 {
492 	if (rt_is_raid0(rs->raid_type))
493 		return RAID0_VALID_FLAGS;
494 	else if (rt_is_raid1(rs->raid_type))
495 		return RAID1_VALID_FLAGS;
496 	else if (rt_is_raid10(rs->raid_type))
497 		return RAID10_VALID_FLAGS;
498 	else if (rt_is_raid45(rs->raid_type))
499 		return RAID45_VALID_FLAGS;
500 	else if (rt_is_raid6(rs->raid_type))
501 		return RAID6_VALID_FLAGS;
502 
503 	return 0;
504 }
505 
506 /*
507  * Check for valid flags set on @rs
508  *
509  * Has to be called after parsing of the ctr flags!
510  */
511 static int rs_check_for_valid_flags(struct raid_set *rs)
512 {
513 	if (rs->ctr_flags & ~__valid_flags(rs)) {
514 		rs->ti->error = "Invalid flags combination";
515 		return -EINVAL;
516 	}
517 
518 	return 0;
519 }
520 
521 /* MD raid10 bit definitions and helpers */
522 #define RAID10_OFFSET			(1 << 16) /* stripes with data copies area adjacent on devices */
523 #define RAID10_BROCKEN_USE_FAR_SETS	(1 << 17) /* Broken in raid10.c: use sets instead of whole stripe rotation */
524 #define RAID10_USE_FAR_SETS		(1 << 18) /* Use sets instead of whole stripe rotation */
525 #define RAID10_FAR_COPIES_SHIFT		8	  /* raid10 # far copies shift (2nd byte of layout) */
526 
527 /* Return md raid10 near copies for @layout */
528 static unsigned int __raid10_near_copies(int layout)
529 {
530 	return layout & 0xFF;
531 }
532 
533 /* Return md raid10 far copies for @layout */
534 static unsigned int __raid10_far_copies(int layout)
535 {
536 	return __raid10_near_copies(layout >> RAID10_FAR_COPIES_SHIFT);
537 }
538 
539 /* Return true if md raid10 offset for @layout */
540 static bool __is_raid10_offset(int layout)
541 {
542 	return !!(layout & RAID10_OFFSET);
543 }
544 
545 /* Return true if md raid10 near for @layout */
546 static bool __is_raid10_near(int layout)
547 {
548 	return !__is_raid10_offset(layout) && __raid10_near_copies(layout) > 1;
549 }
550 
551 /* Return true if md raid10 far for @layout */
552 static bool __is_raid10_far(int layout)
553 {
554 	return !__is_raid10_offset(layout) && __raid10_far_copies(layout) > 1;
555 }
556 
557 /* Return md raid10 layout string for @layout */
558 static const char *raid10_md_layout_to_format(int layout)
559 {
560 	/*
561 	 * Bit 16 stands for "offset"
562 	 * (i.e. adjacent stripes hold copies)
563 	 *
564 	 * Refer to MD's raid10.c for details
565 	 */
566 	if (__is_raid10_offset(layout))
567 		return "offset";
568 
569 	if (__raid10_near_copies(layout) > 1)
570 		return "near";
571 
572 	if (__raid10_far_copies(layout) > 1)
573 		return "far";
574 
575 	return "unknown";
576 }
577 
578 /* Return md raid10 algorithm for @name */
579 static int raid10_name_to_format(const char *name)
580 {
581 	if (!strcasecmp(name, "near"))
582 		return ALGORITHM_RAID10_NEAR;
583 	else if (!strcasecmp(name, "offset"))
584 		return ALGORITHM_RAID10_OFFSET;
585 	else if (!strcasecmp(name, "far"))
586 		return ALGORITHM_RAID10_FAR;
587 
588 	return -EINVAL;
589 }
590 
591 /* Return md raid10 copies for @layout */
592 static unsigned int raid10_md_layout_to_copies(int layout)
593 {
594 	return max(__raid10_near_copies(layout), __raid10_far_copies(layout));
595 }
596 
597 /* Return md raid10 format id for @format string */
598 static int raid10_format_to_md_layout(struct raid_set *rs,
599 				      unsigned int algorithm,
600 				      unsigned int copies)
601 {
602 	unsigned int n = 1, f = 1, r = 0;
603 
604 	/*
605 	 * MD resilienece flaw:
606 	 *
607 	 * enabling use_far_sets for far/offset formats causes copies
608 	 * to be colocated on the same devs together with their origins!
609 	 *
610 	 * -> disable it for now in the definition above
611 	 */
612 	if (algorithm == ALGORITHM_RAID10_DEFAULT ||
613 	    algorithm == ALGORITHM_RAID10_NEAR)
614 		n = copies;
615 
616 	else if (algorithm == ALGORITHM_RAID10_OFFSET) {
617 		f = copies;
618 		r = RAID10_OFFSET;
619 		if (!test_bit(__CTR_FLAG_RAID10_USE_NEAR_SETS, &rs->ctr_flags))
620 			r |= RAID10_USE_FAR_SETS;
621 
622 	} else if (algorithm == ALGORITHM_RAID10_FAR) {
623 		f = copies;
624 		if (!test_bit(__CTR_FLAG_RAID10_USE_NEAR_SETS, &rs->ctr_flags))
625 			r |= RAID10_USE_FAR_SETS;
626 
627 	} else
628 		return -EINVAL;
629 
630 	return r | (f << RAID10_FAR_COPIES_SHIFT) | n;
631 }
632 /* END: MD raid10 bit definitions and helpers */
633 
634 /* Check for any of the raid10 algorithms */
635 static bool __got_raid10(struct raid_type *rtp, const int layout)
636 {
637 	if (rtp->level == 10) {
638 		switch (rtp->algorithm) {
639 		case ALGORITHM_RAID10_DEFAULT:
640 		case ALGORITHM_RAID10_NEAR:
641 			return __is_raid10_near(layout);
642 		case ALGORITHM_RAID10_OFFSET:
643 			return __is_raid10_offset(layout);
644 		case ALGORITHM_RAID10_FAR:
645 			return __is_raid10_far(layout);
646 		default:
647 			break;
648 		}
649 	}
650 
651 	return false;
652 }
653 
654 /* Return raid_type for @name */
655 static struct raid_type *get_raid_type(const char *name)
656 {
657 	struct raid_type *rtp = raid_types + ARRAY_SIZE(raid_types);
658 
659 	while (rtp-- > raid_types)
660 		if (!strcasecmp(rtp->name, name))
661 			return rtp;
662 
663 	return NULL;
664 }
665 
666 /* Return raid_type for @name based derived from @level and @layout */
667 static struct raid_type *get_raid_type_by_ll(const int level, const int layout)
668 {
669 	struct raid_type *rtp = raid_types + ARRAY_SIZE(raid_types);
670 
671 	while (rtp-- > raid_types) {
672 		/* RAID10 special checks based on @layout flags/properties */
673 		if (rtp->level == level &&
674 		    (__got_raid10(rtp, layout) || rtp->algorithm == layout))
675 			return rtp;
676 	}
677 
678 	return NULL;
679 }
680 
681 /* Adjust rdev sectors */
682 static void rs_set_rdev_sectors(struct raid_set *rs)
683 {
684 	struct mddev *mddev = &rs->md;
685 	struct md_rdev *rdev;
686 
687 	/*
688 	 * raid10 sets rdev->sector to the device size, which
689 	 * is unintended in case of out-of-place reshaping
690 	 */
691 	rdev_for_each(rdev, mddev)
692 		if (!test_bit(Journal, &rdev->flags))
693 			rdev->sectors = mddev->dev_sectors;
694 }
695 
696 /*
697  * Change bdev capacity of @rs in case of a disk add/remove reshape
698  */
699 static void rs_set_capacity(struct raid_set *rs)
700 {
701 	struct gendisk *gendisk = dm_disk(dm_table_get_md(rs->ti->table));
702 
703 	set_capacity_and_notify(gendisk, rs->md.array_sectors);
704 }
705 
706 /*
707  * Set the mddev properties in @rs to the current
708  * ones retrieved from the freshest superblock
709  */
710 static void rs_set_cur(struct raid_set *rs)
711 {
712 	struct mddev *mddev = &rs->md;
713 
714 	mddev->new_level = mddev->level;
715 	mddev->new_layout = mddev->layout;
716 	mddev->new_chunk_sectors = mddev->chunk_sectors;
717 }
718 
719 /*
720  * Set the mddev properties in @rs to the new
721  * ones requested by the ctr
722  */
723 static void rs_set_new(struct raid_set *rs)
724 {
725 	struct mddev *mddev = &rs->md;
726 
727 	mddev->level = mddev->new_level;
728 	mddev->layout = mddev->new_layout;
729 	mddev->chunk_sectors = mddev->new_chunk_sectors;
730 	mddev->raid_disks = rs->raid_disks;
731 	mddev->delta_disks = 0;
732 }
733 
734 static struct raid_set *raid_set_alloc(struct dm_target *ti, struct raid_type *raid_type,
735 				       unsigned int raid_devs)
736 {
737 	unsigned int i;
738 	struct raid_set *rs;
739 
740 	if (raid_devs <= raid_type->parity_devs) {
741 		ti->error = "Insufficient number of devices";
742 		return ERR_PTR(-EINVAL);
743 	}
744 
745 	rs = kzalloc(struct_size(rs, dev, raid_devs), GFP_KERNEL);
746 	if (!rs) {
747 		ti->error = "Cannot allocate raid context";
748 		return ERR_PTR(-ENOMEM);
749 	}
750 
751 	mddev_init(&rs->md);
752 
753 	rs->raid_disks = raid_devs;
754 	rs->delta_disks = 0;
755 
756 	rs->ti = ti;
757 	rs->raid_type = raid_type;
758 	rs->stripe_cache_entries = 256;
759 	rs->md.raid_disks = raid_devs;
760 	rs->md.level = raid_type->level;
761 	rs->md.new_level = rs->md.level;
762 	rs->md.layout = raid_type->algorithm;
763 	rs->md.new_layout = rs->md.layout;
764 	rs->md.delta_disks = 0;
765 	rs->md.recovery_cp = MaxSector;
766 
767 	for (i = 0; i < raid_devs; i++)
768 		md_rdev_init(&rs->dev[i].rdev);
769 
770 	/*
771 	 * Remaining items to be initialized by further RAID params:
772 	 *  rs->md.persistent
773 	 *  rs->md.external
774 	 *  rs->md.chunk_sectors
775 	 *  rs->md.new_chunk_sectors
776 	 *  rs->md.dev_sectors
777 	 */
778 
779 	return rs;
780 }
781 
782 /* Free all @rs allocations */
783 static void raid_set_free(struct raid_set *rs)
784 {
785 	int i;
786 
787 	if (rs->journal_dev.dev) {
788 		md_rdev_clear(&rs->journal_dev.rdev);
789 		dm_put_device(rs->ti, rs->journal_dev.dev);
790 	}
791 
792 	for (i = 0; i < rs->raid_disks; i++) {
793 		if (rs->dev[i].meta_dev)
794 			dm_put_device(rs->ti, rs->dev[i].meta_dev);
795 		md_rdev_clear(&rs->dev[i].rdev);
796 		if (rs->dev[i].data_dev)
797 			dm_put_device(rs->ti, rs->dev[i].data_dev);
798 	}
799 
800 	kfree(rs);
801 }
802 
803 /*
804  * For every device we have two words
805  *  <meta_dev>: meta device name or '-' if missing
806  *  <data_dev>: data device name or '-' if missing
807  *
808  * The following are permitted:
809  *    - -
810  *    - <data_dev>
811  *    <meta_dev> <data_dev>
812  *
813  * The following is not allowed:
814  *    <meta_dev> -
815  *
816  * This code parses those words.  If there is a failure,
817  * the caller must use raid_set_free() to unwind the operations.
818  */
819 static int parse_dev_params(struct raid_set *rs, struct dm_arg_set *as)
820 {
821 	int i;
822 	int rebuild = 0;
823 	int metadata_available = 0;
824 	int r = 0;
825 	const char *arg;
826 
827 	/* Put off the number of raid devices argument to get to dev pairs */
828 	arg = dm_shift_arg(as);
829 	if (!arg)
830 		return -EINVAL;
831 
832 	for (i = 0; i < rs->raid_disks; i++) {
833 		rs->dev[i].rdev.raid_disk = i;
834 
835 		rs->dev[i].meta_dev = NULL;
836 		rs->dev[i].data_dev = NULL;
837 
838 		/*
839 		 * There are no offsets initially.
840 		 * Out of place reshape will set them accordingly.
841 		 */
842 		rs->dev[i].rdev.data_offset = 0;
843 		rs->dev[i].rdev.new_data_offset = 0;
844 		rs->dev[i].rdev.mddev = &rs->md;
845 
846 		arg = dm_shift_arg(as);
847 		if (!arg)
848 			return -EINVAL;
849 
850 		if (strcmp(arg, "-")) {
851 			r = dm_get_device(rs->ti, arg, dm_table_get_mode(rs->ti->table),
852 					  &rs->dev[i].meta_dev);
853 			if (r) {
854 				rs->ti->error = "RAID metadata device lookup failure";
855 				return r;
856 			}
857 
858 			rs->dev[i].rdev.sb_page = alloc_page(GFP_KERNEL);
859 			if (!rs->dev[i].rdev.sb_page) {
860 				rs->ti->error = "Failed to allocate superblock page";
861 				return -ENOMEM;
862 			}
863 		}
864 
865 		arg = dm_shift_arg(as);
866 		if (!arg)
867 			return -EINVAL;
868 
869 		if (!strcmp(arg, "-")) {
870 			if (!test_bit(In_sync, &rs->dev[i].rdev.flags) &&
871 			    (!rs->dev[i].rdev.recovery_offset)) {
872 				rs->ti->error = "Drive designated for rebuild not specified";
873 				return -EINVAL;
874 			}
875 
876 			if (rs->dev[i].meta_dev) {
877 				rs->ti->error = "No data device supplied with metadata device";
878 				return -EINVAL;
879 			}
880 
881 			continue;
882 		}
883 
884 		r = dm_get_device(rs->ti, arg, dm_table_get_mode(rs->ti->table),
885 				  &rs->dev[i].data_dev);
886 		if (r) {
887 			rs->ti->error = "RAID device lookup failure";
888 			return r;
889 		}
890 
891 		if (rs->dev[i].meta_dev) {
892 			metadata_available = 1;
893 			rs->dev[i].rdev.meta_bdev = rs->dev[i].meta_dev->bdev;
894 		}
895 		rs->dev[i].rdev.bdev = rs->dev[i].data_dev->bdev;
896 		list_add_tail(&rs->dev[i].rdev.same_set, &rs->md.disks);
897 		if (!test_bit(In_sync, &rs->dev[i].rdev.flags))
898 			rebuild++;
899 	}
900 
901 	if (rs->journal_dev.dev)
902 		list_add_tail(&rs->journal_dev.rdev.same_set, &rs->md.disks);
903 
904 	if (metadata_available) {
905 		rs->md.external = 0;
906 		rs->md.persistent = 1;
907 		rs->md.major_version = 2;
908 	} else if (rebuild && !rs->md.recovery_cp) {
909 		/*
910 		 * Without metadata, we will not be able to tell if the array
911 		 * is in-sync or not - we must assume it is not.  Therefore,
912 		 * it is impossible to rebuild a drive.
913 		 *
914 		 * Even if there is metadata, the on-disk information may
915 		 * indicate that the array is not in-sync and it will then
916 		 * fail at that time.
917 		 *
918 		 * User could specify 'nosync' option if desperate.
919 		 */
920 		rs->ti->error = "Unable to rebuild drive while array is not in-sync";
921 		return -EINVAL;
922 	}
923 
924 	return 0;
925 }
926 
927 /*
928  * validate_region_size
929  * @rs
930  * @region_size:  region size in sectors.  If 0, pick a size (4MiB default).
931  *
932  * Set rs->md.bitmap_info.chunksize (which really refers to 'region size').
933  * Ensure that (ti->len/region_size < 2^21) - required by MD bitmap.
934  *
935  * Returns: 0 on success, -EINVAL on failure.
936  */
937 static int validate_region_size(struct raid_set *rs, unsigned long region_size)
938 {
939 	unsigned long min_region_size = rs->ti->len / (1 << 21);
940 
941 	if (rs_is_raid0(rs))
942 		return 0;
943 
944 	if (!region_size) {
945 		/*
946 		 * Choose a reasonable default.	 All figures in sectors.
947 		 */
948 		if (min_region_size > (1 << 13)) {
949 			/* If not a power of 2, make it the next power of 2 */
950 			region_size = roundup_pow_of_two(min_region_size);
951 			DMINFO("Choosing default region size of %lu sectors",
952 			       region_size);
953 		} else {
954 			DMINFO("Choosing default region size of 4MiB");
955 			region_size = 1 << 13; /* sectors */
956 		}
957 	} else {
958 		/*
959 		 * Validate user-supplied value.
960 		 */
961 		if (region_size > rs->ti->len) {
962 			rs->ti->error = "Supplied region size is too large";
963 			return -EINVAL;
964 		}
965 
966 		if (region_size < min_region_size) {
967 			DMERR("Supplied region_size (%lu sectors) below minimum (%lu)",
968 			      region_size, min_region_size);
969 			rs->ti->error = "Supplied region size is too small";
970 			return -EINVAL;
971 		}
972 
973 		if (!is_power_of_2(region_size)) {
974 			rs->ti->error = "Region size is not a power of 2";
975 			return -EINVAL;
976 		}
977 
978 		if (region_size < rs->md.chunk_sectors) {
979 			rs->ti->error = "Region size is smaller than the chunk size";
980 			return -EINVAL;
981 		}
982 	}
983 
984 	/*
985 	 * Convert sectors to bytes.
986 	 */
987 	rs->md.bitmap_info.chunksize = to_bytes(region_size);
988 
989 	return 0;
990 }
991 
992 /*
993  * validate_raid_redundancy
994  * @rs
995  *
996  * Determine if there are enough devices in the array that haven't
997  * failed (or are being rebuilt) to form a usable array.
998  *
999  * Returns: 0 on success, -EINVAL on failure.
1000  */
1001 static int validate_raid_redundancy(struct raid_set *rs)
1002 {
1003 	unsigned int i, rebuild_cnt = 0;
1004 	unsigned int rebuilds_per_group = 0, copies;
1005 	unsigned int group_size, last_group_start;
1006 
1007 	for (i = 0; i < rs->md.raid_disks; i++)
1008 		if (!test_bit(In_sync, &rs->dev[i].rdev.flags) ||
1009 		    !rs->dev[i].rdev.sb_page)
1010 			rebuild_cnt++;
1011 
1012 	switch (rs->md.level) {
1013 	case 0:
1014 		break;
1015 	case 1:
1016 		if (rebuild_cnt >= rs->md.raid_disks)
1017 			goto too_many;
1018 		break;
1019 	case 4:
1020 	case 5:
1021 	case 6:
1022 		if (rebuild_cnt > rs->raid_type->parity_devs)
1023 			goto too_many;
1024 		break;
1025 	case 10:
1026 		copies = raid10_md_layout_to_copies(rs->md.new_layout);
1027 		if (copies < 2) {
1028 			DMERR("Bogus raid10 data copies < 2!");
1029 			return -EINVAL;
1030 		}
1031 
1032 		if (rebuild_cnt < copies)
1033 			break;
1034 
1035 		/*
1036 		 * It is possible to have a higher rebuild count for RAID10,
1037 		 * as long as the failed devices occur in different mirror
1038 		 * groups (i.e. different stripes).
1039 		 *
1040 		 * When checking "near" format, make sure no adjacent devices
1041 		 * have failed beyond what can be handled.  In addition to the
1042 		 * simple case where the number of devices is a multiple of the
1043 		 * number of copies, we must also handle cases where the number
1044 		 * of devices is not a multiple of the number of copies.
1045 		 * E.g.	   dev1 dev2 dev3 dev4 dev5
1046 		 *	    A	 A    B	   B	C
1047 		 *	    C	 D    D	   E	E
1048 		 */
1049 		if (__is_raid10_near(rs->md.new_layout)) {
1050 			for (i = 0; i < rs->md.raid_disks; i++) {
1051 				if (!(i % copies))
1052 					rebuilds_per_group = 0;
1053 				if ((!rs->dev[i].rdev.sb_page ||
1054 				    !test_bit(In_sync, &rs->dev[i].rdev.flags)) &&
1055 				    (++rebuilds_per_group >= copies))
1056 					goto too_many;
1057 			}
1058 			break;
1059 		}
1060 
1061 		/*
1062 		 * When checking "far" and "offset" formats, we need to ensure
1063 		 * that the device that holds its copy is not also dead or
1064 		 * being rebuilt.  (Note that "far" and "offset" formats only
1065 		 * support two copies right now.  These formats also only ever
1066 		 * use the 'use_far_sets' variant.)
1067 		 *
1068 		 * This check is somewhat complicated by the need to account
1069 		 * for arrays that are not a multiple of (far) copies.	This
1070 		 * results in the need to treat the last (potentially larger)
1071 		 * set differently.
1072 		 */
1073 		group_size = (rs->md.raid_disks / copies);
1074 		last_group_start = (rs->md.raid_disks / group_size) - 1;
1075 		last_group_start *= group_size;
1076 		for (i = 0; i < rs->md.raid_disks; i++) {
1077 			if (!(i % copies) && !(i > last_group_start))
1078 				rebuilds_per_group = 0;
1079 			if ((!rs->dev[i].rdev.sb_page ||
1080 			     !test_bit(In_sync, &rs->dev[i].rdev.flags)) &&
1081 			    (++rebuilds_per_group >= copies))
1082 					goto too_many;
1083 		}
1084 		break;
1085 	default:
1086 		if (rebuild_cnt)
1087 			return -EINVAL;
1088 	}
1089 
1090 	return 0;
1091 
1092 too_many:
1093 	return -EINVAL;
1094 }
1095 
1096 /*
1097  * Possible arguments are...
1098  *	<chunk_size> [optional_args]
1099  *
1100  * Argument definitions
1101  *    <chunk_size>			The number of sectors per disk that
1102  *					will form the "stripe"
1103  *    [[no]sync]			Force or prevent recovery of the
1104  *					entire array
1105  *    [rebuild <idx>]			Rebuild the drive indicated by the index
1106  *    [daemon_sleep <ms>]		Time between bitmap daemon work to
1107  *					clear bits
1108  *    [min_recovery_rate <kB/sec/disk>]	Throttle RAID initialization
1109  *    [max_recovery_rate <kB/sec/disk>]	Throttle RAID initialization
1110  *    [write_mostly <idx>]		Indicate a write mostly drive via index
1111  *    [max_write_behind <sectors>]	See '-write-behind=' (man mdadm)
1112  *    [stripe_cache <sectors>]		Stripe cache size for higher RAIDs
1113  *    [region_size <sectors>]		Defines granularity of bitmap
1114  *    [journal_dev <dev>]		raid4/5/6 journaling deviice
1115  *    					(i.e. write hole closing log)
1116  *
1117  * RAID10-only options:
1118  *    [raid10_copies <# copies>]	Number of copies.  (Default: 2)
1119  *    [raid10_format <near|far|offset>] Layout algorithm.  (Default: near)
1120  */
1121 static int parse_raid_params(struct raid_set *rs, struct dm_arg_set *as,
1122 			     unsigned int num_raid_params)
1123 {
1124 	int value, raid10_format = ALGORITHM_RAID10_DEFAULT;
1125 	unsigned int raid10_copies = 2;
1126 	unsigned int i, write_mostly = 0;
1127 	unsigned int region_size = 0;
1128 	sector_t max_io_len;
1129 	const char *arg, *key;
1130 	struct raid_dev *rd;
1131 	struct raid_type *rt = rs->raid_type;
1132 
1133 	arg = dm_shift_arg(as);
1134 	num_raid_params--; /* Account for chunk_size argument */
1135 
1136 	if (kstrtoint(arg, 10, &value) < 0) {
1137 		rs->ti->error = "Bad numerical argument given for chunk_size";
1138 		return -EINVAL;
1139 	}
1140 
1141 	/*
1142 	 * First, parse the in-order required arguments
1143 	 * "chunk_size" is the only argument of this type.
1144 	 */
1145 	if (rt_is_raid1(rt)) {
1146 		if (value)
1147 			DMERR("Ignoring chunk size parameter for RAID 1");
1148 		value = 0;
1149 	} else if (!is_power_of_2(value)) {
1150 		rs->ti->error = "Chunk size must be a power of 2";
1151 		return -EINVAL;
1152 	} else if (value < 8) {
1153 		rs->ti->error = "Chunk size value is too small";
1154 		return -EINVAL;
1155 	}
1156 
1157 	rs->md.new_chunk_sectors = rs->md.chunk_sectors = value;
1158 
1159 	/*
1160 	 * We set each individual device as In_sync with a completed
1161 	 * 'recovery_offset'.  If there has been a device failure or
1162 	 * replacement then one of the following cases applies:
1163 	 *
1164 	 *   1) User specifies 'rebuild'.
1165 	 *	- Device is reset when param is read.
1166 	 *   2) A new device is supplied.
1167 	 *	- No matching superblock found, resets device.
1168 	 *   3) Device failure was transient and returns on reload.
1169 	 *	- Failure noticed, resets device for bitmap replay.
1170 	 *   4) Device hadn't completed recovery after previous failure.
1171 	 *	- Superblock is read and overrides recovery_offset.
1172 	 *
1173 	 * What is found in the superblocks of the devices is always
1174 	 * authoritative, unless 'rebuild' or '[no]sync' was specified.
1175 	 */
1176 	for (i = 0; i < rs->raid_disks; i++) {
1177 		set_bit(In_sync, &rs->dev[i].rdev.flags);
1178 		rs->dev[i].rdev.recovery_offset = MaxSector;
1179 	}
1180 
1181 	/*
1182 	 * Second, parse the unordered optional arguments
1183 	 */
1184 	for (i = 0; i < num_raid_params; i++) {
1185 		key = dm_shift_arg(as);
1186 		if (!key) {
1187 			rs->ti->error = "Not enough raid parameters given";
1188 			return -EINVAL;
1189 		}
1190 
1191 		if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_NOSYNC))) {
1192 			if (test_and_set_bit(__CTR_FLAG_NOSYNC, &rs->ctr_flags)) {
1193 				rs->ti->error = "Only one 'nosync' argument allowed";
1194 				return -EINVAL;
1195 			}
1196 			continue;
1197 		}
1198 		if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_SYNC))) {
1199 			if (test_and_set_bit(__CTR_FLAG_SYNC, &rs->ctr_flags)) {
1200 				rs->ti->error = "Only one 'sync' argument allowed";
1201 				return -EINVAL;
1202 			}
1203 			continue;
1204 		}
1205 		if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_RAID10_USE_NEAR_SETS))) {
1206 			if (test_and_set_bit(__CTR_FLAG_RAID10_USE_NEAR_SETS, &rs->ctr_flags)) {
1207 				rs->ti->error = "Only one 'raid10_use_new_sets' argument allowed";
1208 				return -EINVAL;
1209 			}
1210 			continue;
1211 		}
1212 
1213 		arg = dm_shift_arg(as);
1214 		i++; /* Account for the argument pairs */
1215 		if (!arg) {
1216 			rs->ti->error = "Wrong number of raid parameters given";
1217 			return -EINVAL;
1218 		}
1219 
1220 		/*
1221 		 * Parameters that take a string value are checked here.
1222 		 */
1223 		/* "raid10_format {near|offset|far} */
1224 		if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_RAID10_FORMAT))) {
1225 			if (test_and_set_bit(__CTR_FLAG_RAID10_FORMAT, &rs->ctr_flags)) {
1226 				rs->ti->error = "Only one 'raid10_format' argument pair allowed";
1227 				return -EINVAL;
1228 			}
1229 			if (!rt_is_raid10(rt)) {
1230 				rs->ti->error = "'raid10_format' is an invalid parameter for this RAID type";
1231 				return -EINVAL;
1232 			}
1233 			raid10_format = raid10_name_to_format(arg);
1234 			if (raid10_format < 0) {
1235 				rs->ti->error = "Invalid 'raid10_format' value given";
1236 				return raid10_format;
1237 			}
1238 			continue;
1239 		}
1240 
1241 		/* "journal_dev <dev>" */
1242 		if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_JOURNAL_DEV))) {
1243 			int r;
1244 			struct md_rdev *jdev;
1245 
1246 			if (test_and_set_bit(__CTR_FLAG_JOURNAL_DEV, &rs->ctr_flags)) {
1247 				rs->ti->error = "Only one raid4/5/6 set journaling device allowed";
1248 				return -EINVAL;
1249 			}
1250 			if (!rt_is_raid456(rt)) {
1251 				rs->ti->error = "'journal_dev' is an invalid parameter for this RAID type";
1252 				return -EINVAL;
1253 			}
1254 			r = dm_get_device(rs->ti, arg, dm_table_get_mode(rs->ti->table),
1255 					  &rs->journal_dev.dev);
1256 			if (r) {
1257 				rs->ti->error = "raid4/5/6 journal device lookup failure";
1258 				return r;
1259 			}
1260 			jdev = &rs->journal_dev.rdev;
1261 			md_rdev_init(jdev);
1262 			jdev->mddev = &rs->md;
1263 			jdev->bdev = rs->journal_dev.dev->bdev;
1264 			jdev->sectors = to_sector(i_size_read(jdev->bdev->bd_inode));
1265 			if (jdev->sectors < MIN_RAID456_JOURNAL_SPACE) {
1266 				rs->ti->error = "No space for raid4/5/6 journal";
1267 				return -ENOSPC;
1268 			}
1269 			rs->journal_dev.mode = R5C_JOURNAL_MODE_WRITE_THROUGH;
1270 			set_bit(Journal, &jdev->flags);
1271 			continue;
1272 		}
1273 
1274 		/* "journal_mode <mode>" ("journal_dev" mandatory!) */
1275 		if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_JOURNAL_MODE))) {
1276 			int r;
1277 
1278 			if (!test_bit(__CTR_FLAG_JOURNAL_DEV, &rs->ctr_flags)) {
1279 				rs->ti->error = "raid4/5/6 'journal_mode' is invalid without 'journal_dev'";
1280 				return -EINVAL;
1281 			}
1282 			if (test_and_set_bit(__CTR_FLAG_JOURNAL_MODE, &rs->ctr_flags)) {
1283 				rs->ti->error = "Only one raid4/5/6 'journal_mode' argument allowed";
1284 				return -EINVAL;
1285 			}
1286 			r = dm_raid_journal_mode_to_md(arg);
1287 			if (r < 0) {
1288 				rs->ti->error = "Invalid 'journal_mode' argument";
1289 				return r;
1290 			}
1291 			rs->journal_dev.mode = r;
1292 			continue;
1293 		}
1294 
1295 		/*
1296 		 * Parameters with number values from here on.
1297 		 */
1298 		if (kstrtoint(arg, 10, &value) < 0) {
1299 			rs->ti->error = "Bad numerical argument given in raid params";
1300 			return -EINVAL;
1301 		}
1302 
1303 		if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_REBUILD))) {
1304 			/*
1305 			 * "rebuild" is being passed in by userspace to provide
1306 			 * indexes of replaced devices and to set up additional
1307 			 * devices on raid level takeover.
1308 			 */
1309 			if (!__within_range(value, 0, rs->raid_disks - 1)) {
1310 				rs->ti->error = "Invalid rebuild index given";
1311 				return -EINVAL;
1312 			}
1313 
1314 			if (test_and_set_bit(value, (void *) rs->rebuild_disks)) {
1315 				rs->ti->error = "rebuild for this index already given";
1316 				return -EINVAL;
1317 			}
1318 
1319 			rd = rs->dev + value;
1320 			clear_bit(In_sync, &rd->rdev.flags);
1321 			clear_bit(Faulty, &rd->rdev.flags);
1322 			rd->rdev.recovery_offset = 0;
1323 			set_bit(__CTR_FLAG_REBUILD, &rs->ctr_flags);
1324 		} else if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_WRITE_MOSTLY))) {
1325 			if (!rt_is_raid1(rt)) {
1326 				rs->ti->error = "write_mostly option is only valid for RAID1";
1327 				return -EINVAL;
1328 			}
1329 
1330 			if (!__within_range(value, 0, rs->md.raid_disks - 1)) {
1331 				rs->ti->error = "Invalid write_mostly index given";
1332 				return -EINVAL;
1333 			}
1334 
1335 			write_mostly++;
1336 			set_bit(WriteMostly, &rs->dev[value].rdev.flags);
1337 			set_bit(__CTR_FLAG_WRITE_MOSTLY, &rs->ctr_flags);
1338 		} else if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_MAX_WRITE_BEHIND))) {
1339 			if (!rt_is_raid1(rt)) {
1340 				rs->ti->error = "max_write_behind option is only valid for RAID1";
1341 				return -EINVAL;
1342 			}
1343 
1344 			if (test_and_set_bit(__CTR_FLAG_MAX_WRITE_BEHIND, &rs->ctr_flags)) {
1345 				rs->ti->error = "Only one max_write_behind argument pair allowed";
1346 				return -EINVAL;
1347 			}
1348 
1349 			/*
1350 			 * In device-mapper, we specify things in sectors, but
1351 			 * MD records this value in kB
1352 			 */
1353 			if (value < 0 || value / 2 > COUNTER_MAX) {
1354 				rs->ti->error = "Max write-behind limit out of range";
1355 				return -EINVAL;
1356 			}
1357 
1358 			rs->md.bitmap_info.max_write_behind = value / 2;
1359 		} else if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_DAEMON_SLEEP))) {
1360 			if (test_and_set_bit(__CTR_FLAG_DAEMON_SLEEP, &rs->ctr_flags)) {
1361 				rs->ti->error = "Only one daemon_sleep argument pair allowed";
1362 				return -EINVAL;
1363 			}
1364 			if (value < 0) {
1365 				rs->ti->error = "daemon sleep period out of range";
1366 				return -EINVAL;
1367 			}
1368 			rs->md.bitmap_info.daemon_sleep = value;
1369 		} else if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_DATA_OFFSET))) {
1370 			/* Userspace passes new data_offset after having extended the the data image LV */
1371 			if (test_and_set_bit(__CTR_FLAG_DATA_OFFSET, &rs->ctr_flags)) {
1372 				rs->ti->error = "Only one data_offset argument pair allowed";
1373 				return -EINVAL;
1374 			}
1375 			/* Ensure sensible data offset */
1376 			if (value < 0 ||
1377 			    (value && (value < MIN_FREE_RESHAPE_SPACE || value % to_sector(PAGE_SIZE)))) {
1378 				rs->ti->error = "Bogus data_offset value";
1379 				return -EINVAL;
1380 			}
1381 			rs->data_offset = value;
1382 		} else if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_DELTA_DISKS))) {
1383 			/* Define the +/-# of disks to add to/remove from the given raid set */
1384 			if (test_and_set_bit(__CTR_FLAG_DELTA_DISKS, &rs->ctr_flags)) {
1385 				rs->ti->error = "Only one delta_disks argument pair allowed";
1386 				return -EINVAL;
1387 			}
1388 			/* Ensure MAX_RAID_DEVICES and raid type minimal_devs! */
1389 			if (!__within_range(abs(value), 1, MAX_RAID_DEVICES - rt->minimal_devs)) {
1390 				rs->ti->error = "Too many delta_disk requested";
1391 				return -EINVAL;
1392 			}
1393 
1394 			rs->delta_disks = value;
1395 		} else if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_STRIPE_CACHE))) {
1396 			if (test_and_set_bit(__CTR_FLAG_STRIPE_CACHE, &rs->ctr_flags)) {
1397 				rs->ti->error = "Only one stripe_cache argument pair allowed";
1398 				return -EINVAL;
1399 			}
1400 
1401 			if (!rt_is_raid456(rt)) {
1402 				rs->ti->error = "Inappropriate argument: stripe_cache";
1403 				return -EINVAL;
1404 			}
1405 
1406 			if (value < 0) {
1407 				rs->ti->error = "Bogus stripe cache entries value";
1408 				return -EINVAL;
1409 			}
1410 			rs->stripe_cache_entries = value;
1411 		} else if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_MIN_RECOVERY_RATE))) {
1412 			if (test_and_set_bit(__CTR_FLAG_MIN_RECOVERY_RATE, &rs->ctr_flags)) {
1413 				rs->ti->error = "Only one min_recovery_rate argument pair allowed";
1414 				return -EINVAL;
1415 			}
1416 
1417 			if (value < 0) {
1418 				rs->ti->error = "min_recovery_rate out of range";
1419 				return -EINVAL;
1420 			}
1421 			rs->md.sync_speed_min = value;
1422 		} else if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_MAX_RECOVERY_RATE))) {
1423 			if (test_and_set_bit(__CTR_FLAG_MAX_RECOVERY_RATE, &rs->ctr_flags)) {
1424 				rs->ti->error = "Only one max_recovery_rate argument pair allowed";
1425 				return -EINVAL;
1426 			}
1427 
1428 			if (value < 0) {
1429 				rs->ti->error = "max_recovery_rate out of range";
1430 				return -EINVAL;
1431 			}
1432 			rs->md.sync_speed_max = value;
1433 		} else if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_REGION_SIZE))) {
1434 			if (test_and_set_bit(__CTR_FLAG_REGION_SIZE, &rs->ctr_flags)) {
1435 				rs->ti->error = "Only one region_size argument pair allowed";
1436 				return -EINVAL;
1437 			}
1438 
1439 			region_size = value;
1440 			rs->requested_bitmap_chunk_sectors = value;
1441 		} else if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_RAID10_COPIES))) {
1442 			if (test_and_set_bit(__CTR_FLAG_RAID10_COPIES, &rs->ctr_flags)) {
1443 				rs->ti->error = "Only one raid10_copies argument pair allowed";
1444 				return -EINVAL;
1445 			}
1446 
1447 			if (!__within_range(value, 2, rs->md.raid_disks)) {
1448 				rs->ti->error = "Bad value for 'raid10_copies'";
1449 				return -EINVAL;
1450 			}
1451 
1452 			raid10_copies = value;
1453 		} else {
1454 			DMERR("Unable to parse RAID parameter: %s", key);
1455 			rs->ti->error = "Unable to parse RAID parameter";
1456 			return -EINVAL;
1457 		}
1458 	}
1459 
1460 	if (test_bit(__CTR_FLAG_SYNC, &rs->ctr_flags) &&
1461 	    test_bit(__CTR_FLAG_NOSYNC, &rs->ctr_flags)) {
1462 		rs->ti->error = "sync and nosync are mutually exclusive";
1463 		return -EINVAL;
1464 	}
1465 
1466 	if (test_bit(__CTR_FLAG_REBUILD, &rs->ctr_flags) &&
1467 	    (test_bit(__CTR_FLAG_SYNC, &rs->ctr_flags) ||
1468 	     test_bit(__CTR_FLAG_NOSYNC, &rs->ctr_flags))) {
1469 		rs->ti->error = "sync/nosync and rebuild are mutually exclusive";
1470 		return -EINVAL;
1471 	}
1472 
1473 	if (write_mostly >= rs->md.raid_disks) {
1474 		rs->ti->error = "Can't set all raid1 devices to write_mostly";
1475 		return -EINVAL;
1476 	}
1477 
1478 	if (rs->md.sync_speed_max &&
1479 	    rs->md.sync_speed_min > rs->md.sync_speed_max) {
1480 		rs->ti->error = "Bogus recovery rates";
1481 		return -EINVAL;
1482 	}
1483 
1484 	if (validate_region_size(rs, region_size))
1485 		return -EINVAL;
1486 
1487 	if (rs->md.chunk_sectors)
1488 		max_io_len = rs->md.chunk_sectors;
1489 	else
1490 		max_io_len = region_size;
1491 
1492 	if (dm_set_target_max_io_len(rs->ti, max_io_len))
1493 		return -EINVAL;
1494 
1495 	if (rt_is_raid10(rt)) {
1496 		if (raid10_copies > rs->md.raid_disks) {
1497 			rs->ti->error = "Not enough devices to satisfy specification";
1498 			return -EINVAL;
1499 		}
1500 
1501 		rs->md.new_layout = raid10_format_to_md_layout(rs, raid10_format, raid10_copies);
1502 		if (rs->md.new_layout < 0) {
1503 			rs->ti->error = "Error getting raid10 format";
1504 			return rs->md.new_layout;
1505 		}
1506 
1507 		rt = get_raid_type_by_ll(10, rs->md.new_layout);
1508 		if (!rt) {
1509 			rs->ti->error = "Failed to recognize new raid10 layout";
1510 			return -EINVAL;
1511 		}
1512 
1513 		if ((rt->algorithm == ALGORITHM_RAID10_DEFAULT ||
1514 		     rt->algorithm == ALGORITHM_RAID10_NEAR) &&
1515 		    test_bit(__CTR_FLAG_RAID10_USE_NEAR_SETS, &rs->ctr_flags)) {
1516 			rs->ti->error = "RAID10 format 'near' and 'raid10_use_near_sets' are incompatible";
1517 			return -EINVAL;
1518 		}
1519 	}
1520 
1521 	rs->raid10_copies = raid10_copies;
1522 
1523 	/* Assume there are no metadata devices until the drives are parsed */
1524 	rs->md.persistent = 0;
1525 	rs->md.external = 1;
1526 
1527 	/* Check, if any invalid ctr arguments have been passed in for the raid level */
1528 	return rs_check_for_valid_flags(rs);
1529 }
1530 
1531 /* Set raid4/5/6 cache size */
1532 static int rs_set_raid456_stripe_cache(struct raid_set *rs)
1533 {
1534 	int r;
1535 	struct r5conf *conf;
1536 	struct mddev *mddev = &rs->md;
1537 	uint32_t min_stripes = max(mddev->chunk_sectors, mddev->new_chunk_sectors) / 2;
1538 	uint32_t nr_stripes = rs->stripe_cache_entries;
1539 
1540 	if (!rt_is_raid456(rs->raid_type)) {
1541 		rs->ti->error = "Inappropriate raid level; cannot change stripe_cache size";
1542 		return -EINVAL;
1543 	}
1544 
1545 	if (nr_stripes < min_stripes) {
1546 		DMINFO("Adjusting requested %u stripe cache entries to %u to suit stripe size",
1547 		       nr_stripes, min_stripes);
1548 		nr_stripes = min_stripes;
1549 	}
1550 
1551 	conf = mddev->private;
1552 	if (!conf) {
1553 		rs->ti->error = "Cannot change stripe_cache size on inactive RAID set";
1554 		return -EINVAL;
1555 	}
1556 
1557 	/* Try setting number of stripes in raid456 stripe cache */
1558 	if (conf->min_nr_stripes != nr_stripes) {
1559 		r = raid5_set_cache_size(mddev, nr_stripes);
1560 		if (r) {
1561 			rs->ti->error = "Failed to set raid4/5/6 stripe cache size";
1562 			return r;
1563 		}
1564 
1565 		DMINFO("%u stripe cache entries", nr_stripes);
1566 	}
1567 
1568 	return 0;
1569 }
1570 
1571 /* Return # of data stripes as kept in mddev as of @rs (i.e. as of superblock) */
1572 static unsigned int mddev_data_stripes(struct raid_set *rs)
1573 {
1574 	return rs->md.raid_disks - rs->raid_type->parity_devs;
1575 }
1576 
1577 /* Return # of data stripes of @rs (i.e. as of ctr) */
1578 static unsigned int rs_data_stripes(struct raid_set *rs)
1579 {
1580 	return rs->raid_disks - rs->raid_type->parity_devs;
1581 }
1582 
1583 /*
1584  * Retrieve rdev->sectors from any valid raid device of @rs
1585  * to allow userpace to pass in arbitray "- -" device tupples.
1586  */
1587 static sector_t __rdev_sectors(struct raid_set *rs)
1588 {
1589 	int i;
1590 
1591 	for (i = 0; i < rs->md.raid_disks; i++) {
1592 		struct md_rdev *rdev = &rs->dev[i].rdev;
1593 
1594 		if (!test_bit(Journal, &rdev->flags) &&
1595 		    rdev->bdev && rdev->sectors)
1596 			return rdev->sectors;
1597 	}
1598 
1599 	return 0;
1600 }
1601 
1602 /* Check that calculated dev_sectors fits all component devices. */
1603 static int _check_data_dev_sectors(struct raid_set *rs)
1604 {
1605 	sector_t ds = ~0;
1606 	struct md_rdev *rdev;
1607 
1608 	rdev_for_each(rdev, &rs->md)
1609 		if (!test_bit(Journal, &rdev->flags) && rdev->bdev) {
1610 			ds = min(ds, to_sector(i_size_read(rdev->bdev->bd_inode)));
1611 			if (ds < rs->md.dev_sectors) {
1612 				rs->ti->error = "Component device(s) too small";
1613 				return -EINVAL;
1614 			}
1615 		}
1616 
1617 	return 0;
1618 }
1619 
1620 /* Calculate the sectors per device and per array used for @rs */
1621 static int rs_set_dev_and_array_sectors(struct raid_set *rs, sector_t sectors, bool use_mddev)
1622 {
1623 	int delta_disks;
1624 	unsigned int data_stripes;
1625 	sector_t array_sectors = sectors, dev_sectors = sectors;
1626 	struct mddev *mddev = &rs->md;
1627 
1628 	if (use_mddev) {
1629 		delta_disks = mddev->delta_disks;
1630 		data_stripes = mddev_data_stripes(rs);
1631 	} else {
1632 		delta_disks = rs->delta_disks;
1633 		data_stripes = rs_data_stripes(rs);
1634 	}
1635 
1636 	/* Special raid1 case w/o delta_disks support (yet) */
1637 	if (rt_is_raid1(rs->raid_type))
1638 		;
1639 	else if (rt_is_raid10(rs->raid_type)) {
1640 		if (rs->raid10_copies < 2 ||
1641 		    delta_disks < 0) {
1642 			rs->ti->error = "Bogus raid10 data copies or delta disks";
1643 			return -EINVAL;
1644 		}
1645 
1646 		dev_sectors *= rs->raid10_copies;
1647 		if (sector_div(dev_sectors, data_stripes))
1648 			goto bad;
1649 
1650 		array_sectors = (data_stripes + delta_disks) * dev_sectors;
1651 		if (sector_div(array_sectors, rs->raid10_copies))
1652 			goto bad;
1653 
1654 	} else if (sector_div(dev_sectors, data_stripes))
1655 		goto bad;
1656 
1657 	else
1658 		/* Striped layouts */
1659 		array_sectors = (data_stripes + delta_disks) * dev_sectors;
1660 
1661 	mddev->array_sectors = array_sectors;
1662 	mddev->dev_sectors = dev_sectors;
1663 	rs_set_rdev_sectors(rs);
1664 
1665 	return _check_data_dev_sectors(rs);
1666 bad:
1667 	rs->ti->error = "Target length not divisible by number of data devices";
1668 	return -EINVAL;
1669 }
1670 
1671 /* Setup recovery on @rs */
1672 static void rs_setup_recovery(struct raid_set *rs, sector_t dev_sectors)
1673 {
1674 	/* raid0 does not recover */
1675 	if (rs_is_raid0(rs))
1676 		rs->md.recovery_cp = MaxSector;
1677 	/*
1678 	 * A raid6 set has to be recovered either
1679 	 * completely or for the grown part to
1680 	 * ensure proper parity and Q-Syndrome
1681 	 */
1682 	else if (rs_is_raid6(rs))
1683 		rs->md.recovery_cp = dev_sectors;
1684 	/*
1685 	 * Other raid set types may skip recovery
1686 	 * depending on the 'nosync' flag.
1687 	 */
1688 	else
1689 		rs->md.recovery_cp = test_bit(__CTR_FLAG_NOSYNC, &rs->ctr_flags)
1690 				     ? MaxSector : dev_sectors;
1691 }
1692 
1693 static void do_table_event(struct work_struct *ws)
1694 {
1695 	struct raid_set *rs = container_of(ws, struct raid_set, md.event_work);
1696 
1697 	smp_rmb(); /* Make sure we access most actual mddev properties */
1698 	if (!rs_is_reshaping(rs)) {
1699 		if (rs_is_raid10(rs))
1700 			rs_set_rdev_sectors(rs);
1701 		rs_set_capacity(rs);
1702 	}
1703 	dm_table_event(rs->ti->table);
1704 }
1705 
1706 /*
1707  * Make sure a valid takover (level switch) is being requested on @rs
1708  *
1709  * Conversions of raid sets from one MD personality to another
1710  * have to conform to restrictions which are enforced here.
1711  */
1712 static int rs_check_takeover(struct raid_set *rs)
1713 {
1714 	struct mddev *mddev = &rs->md;
1715 	unsigned int near_copies;
1716 
1717 	if (rs->md.degraded) {
1718 		rs->ti->error = "Can't takeover degraded raid set";
1719 		return -EPERM;
1720 	}
1721 
1722 	if (rs_is_reshaping(rs)) {
1723 		rs->ti->error = "Can't takeover reshaping raid set";
1724 		return -EPERM;
1725 	}
1726 
1727 	switch (mddev->level) {
1728 	case 0:
1729 		/* raid0 -> raid1/5 with one disk */
1730 		if ((mddev->new_level == 1 || mddev->new_level == 5) &&
1731 		    mddev->raid_disks == 1)
1732 			return 0;
1733 
1734 		/* raid0 -> raid10 */
1735 		if (mddev->new_level == 10 &&
1736 		    !(rs->raid_disks % mddev->raid_disks))
1737 			return 0;
1738 
1739 		/* raid0 with multiple disks -> raid4/5/6 */
1740 		if (__within_range(mddev->new_level, 4, 6) &&
1741 		    mddev->new_layout == ALGORITHM_PARITY_N &&
1742 		    mddev->raid_disks > 1)
1743 			return 0;
1744 
1745 		break;
1746 
1747 	case 10:
1748 		/* Can't takeover raid10_offset! */
1749 		if (__is_raid10_offset(mddev->layout))
1750 			break;
1751 
1752 		near_copies = __raid10_near_copies(mddev->layout);
1753 
1754 		/* raid10* -> raid0 */
1755 		if (mddev->new_level == 0) {
1756 			/* Can takeover raid10_near with raid disks divisable by data copies! */
1757 			if (near_copies > 1 &&
1758 			    !(mddev->raid_disks % near_copies)) {
1759 				mddev->raid_disks /= near_copies;
1760 				mddev->delta_disks = mddev->raid_disks;
1761 				return 0;
1762 			}
1763 
1764 			/* Can takeover raid10_far */
1765 			if (near_copies == 1 &&
1766 			    __raid10_far_copies(mddev->layout) > 1)
1767 				return 0;
1768 
1769 			break;
1770 		}
1771 
1772 		/* raid10_{near,far} -> raid1 */
1773 		if (mddev->new_level == 1 &&
1774 		    max(near_copies, __raid10_far_copies(mddev->layout)) == mddev->raid_disks)
1775 			return 0;
1776 
1777 		/* raid10_{near,far} with 2 disks -> raid4/5 */
1778 		if (__within_range(mddev->new_level, 4, 5) &&
1779 		    mddev->raid_disks == 2)
1780 			return 0;
1781 		break;
1782 
1783 	case 1:
1784 		/* raid1 with 2 disks -> raid4/5 */
1785 		if (__within_range(mddev->new_level, 4, 5) &&
1786 		    mddev->raid_disks == 2) {
1787 			mddev->degraded = 1;
1788 			return 0;
1789 		}
1790 
1791 		/* raid1 -> raid0 */
1792 		if (mddev->new_level == 0 &&
1793 		    mddev->raid_disks == 1)
1794 			return 0;
1795 
1796 		/* raid1 -> raid10 */
1797 		if (mddev->new_level == 10)
1798 			return 0;
1799 		break;
1800 
1801 	case 4:
1802 		/* raid4 -> raid0 */
1803 		if (mddev->new_level == 0)
1804 			return 0;
1805 
1806 		/* raid4 -> raid1/5 with 2 disks */
1807 		if ((mddev->new_level == 1 || mddev->new_level == 5) &&
1808 		    mddev->raid_disks == 2)
1809 			return 0;
1810 
1811 		/* raid4 -> raid5/6 with parity N */
1812 		if (__within_range(mddev->new_level, 5, 6) &&
1813 		    mddev->layout == ALGORITHM_PARITY_N)
1814 			return 0;
1815 		break;
1816 
1817 	case 5:
1818 		/* raid5 with parity N -> raid0 */
1819 		if (mddev->new_level == 0 &&
1820 		    mddev->layout == ALGORITHM_PARITY_N)
1821 			return 0;
1822 
1823 		/* raid5 with parity N -> raid4 */
1824 		if (mddev->new_level == 4 &&
1825 		    mddev->layout == ALGORITHM_PARITY_N)
1826 			return 0;
1827 
1828 		/* raid5 with 2 disks -> raid1/4/10 */
1829 		if ((mddev->new_level == 1 || mddev->new_level == 4 || mddev->new_level == 10) &&
1830 		    mddev->raid_disks == 2)
1831 			return 0;
1832 
1833 		/* raid5_* ->  raid6_*_6 with Q-Syndrome N (e.g. raid5_ra -> raid6_ra_6 */
1834 		if (mddev->new_level == 6 &&
1835 		    ((mddev->layout == ALGORITHM_PARITY_N && mddev->new_layout == ALGORITHM_PARITY_N) ||
1836 		      __within_range(mddev->new_layout, ALGORITHM_LEFT_ASYMMETRIC_6, ALGORITHM_RIGHT_SYMMETRIC_6)))
1837 			return 0;
1838 		break;
1839 
1840 	case 6:
1841 		/* raid6 with parity N -> raid0 */
1842 		if (mddev->new_level == 0 &&
1843 		    mddev->layout == ALGORITHM_PARITY_N)
1844 			return 0;
1845 
1846 		/* raid6 with parity N -> raid4 */
1847 		if (mddev->new_level == 4 &&
1848 		    mddev->layout == ALGORITHM_PARITY_N)
1849 			return 0;
1850 
1851 		/* raid6_*_n with Q-Syndrome N -> raid5_* */
1852 		if (mddev->new_level == 5 &&
1853 		    ((mddev->layout == ALGORITHM_PARITY_N && mddev->new_layout == ALGORITHM_PARITY_N) ||
1854 		     __within_range(mddev->new_layout, ALGORITHM_LEFT_ASYMMETRIC, ALGORITHM_RIGHT_SYMMETRIC)))
1855 			return 0;
1856 		break;
1857 
1858 	default:
1859 		break;
1860 	}
1861 
1862 	rs->ti->error = "takeover not possible";
1863 	return -EINVAL;
1864 }
1865 
1866 /* True if @rs requested to be taken over */
1867 static bool rs_takeover_requested(struct raid_set *rs)
1868 {
1869 	return rs->md.new_level != rs->md.level;
1870 }
1871 
1872 /* True if layout is set to reshape. */
1873 static bool rs_is_layout_change(struct raid_set *rs, bool use_mddev)
1874 {
1875 	return (use_mddev ? rs->md.delta_disks : rs->delta_disks) ||
1876 	       rs->md.new_layout != rs->md.layout ||
1877 	       rs->md.new_chunk_sectors != rs->md.chunk_sectors;
1878 }
1879 
1880 /* True if @rs is requested to reshape by ctr */
1881 static bool rs_reshape_requested(struct raid_set *rs)
1882 {
1883 	bool change;
1884 	struct mddev *mddev = &rs->md;
1885 
1886 	if (rs_takeover_requested(rs))
1887 		return false;
1888 
1889 	if (rs_is_raid0(rs))
1890 		return false;
1891 
1892 	change = rs_is_layout_change(rs, false);
1893 
1894 	/* Historical case to support raid1 reshape without delta disks */
1895 	if (rs_is_raid1(rs)) {
1896 		if (rs->delta_disks)
1897 			return !!rs->delta_disks;
1898 
1899 		return !change &&
1900 		       mddev->raid_disks != rs->raid_disks;
1901 	}
1902 
1903 	if (rs_is_raid10(rs))
1904 		return change &&
1905 		       !__is_raid10_far(mddev->new_layout) &&
1906 		       rs->delta_disks >= 0;
1907 
1908 	return change;
1909 }
1910 
1911 /*  Features */
1912 #define	FEATURE_FLAG_SUPPORTS_V190	0x1 /* Supports extended superblock */
1913 
1914 /* State flags for sb->flags */
1915 #define	SB_FLAG_RESHAPE_ACTIVE		0x1
1916 #define	SB_FLAG_RESHAPE_BACKWARDS	0x2
1917 
1918 /*
1919  * This structure is never routinely used by userspace, unlike md superblocks.
1920  * Devices with this superblock should only ever be accessed via device-mapper.
1921  */
1922 #define DM_RAID_MAGIC 0x64526D44
1923 struct dm_raid_superblock {
1924 	__le32 magic;		/* "DmRd" */
1925 	__le32 compat_features;	/* Used to indicate compatible features (like 1.9.0 ondisk metadata extension) */
1926 
1927 	__le32 num_devices;	/* Number of devices in this raid set. (Max 64) */
1928 	__le32 array_position;	/* The position of this drive in the raid set */
1929 
1930 	__le64 events;		/* Incremented by md when superblock updated */
1931 	__le64 failed_devices;	/* Pre 1.9.0 part of bit field of devices to */
1932 				/* indicate failures (see extension below) */
1933 
1934 	/*
1935 	 * This offset tracks the progress of the repair or replacement of
1936 	 * an individual drive.
1937 	 */
1938 	__le64 disk_recovery_offset;
1939 
1940 	/*
1941 	 * This offset tracks the progress of the initial raid set
1942 	 * synchronisation/parity calculation.
1943 	 */
1944 	__le64 array_resync_offset;
1945 
1946 	/*
1947 	 * raid characteristics
1948 	 */
1949 	__le32 level;
1950 	__le32 layout;
1951 	__le32 stripe_sectors;
1952 
1953 	/********************************************************************
1954 	 * BELOW FOLLOW V1.9.0 EXTENSIONS TO THE PRISTINE SUPERBLOCK FORMAT!!!
1955 	 *
1956 	 * FEATURE_FLAG_SUPPORTS_V190 in the compat_features member indicates that those exist
1957 	 */
1958 
1959 	__le32 flags; /* Flags defining array states for reshaping */
1960 
1961 	/*
1962 	 * This offset tracks the progress of a raid
1963 	 * set reshape in order to be able to restart it
1964 	 */
1965 	__le64 reshape_position;
1966 
1967 	/*
1968 	 * These define the properties of the array in case of an interrupted reshape
1969 	 */
1970 	__le32 new_level;
1971 	__le32 new_layout;
1972 	__le32 new_stripe_sectors;
1973 	__le32 delta_disks;
1974 
1975 	__le64 array_sectors; /* Array size in sectors */
1976 
1977 	/*
1978 	 * Sector offsets to data on devices (reshaping).
1979 	 * Needed to support out of place reshaping, thus
1980 	 * not writing over any stripes whilst converting
1981 	 * them from old to new layout
1982 	 */
1983 	__le64 data_offset;
1984 	__le64 new_data_offset;
1985 
1986 	__le64 sectors; /* Used device size in sectors */
1987 
1988 	/*
1989 	 * Additonal Bit field of devices indicating failures to support
1990 	 * up to 256 devices with the 1.9.0 on-disk metadata format
1991 	 */
1992 	__le64 extended_failed_devices[DISKS_ARRAY_ELEMS - 1];
1993 
1994 	__le32 incompat_features;	/* Used to indicate any incompatible features */
1995 
1996 	/* Always set rest up to logical block size to 0 when writing (see get_metadata_device() below). */
1997 } __packed;
1998 
1999 /*
2000  * Check for reshape constraints on raid set @rs:
2001  *
2002  * - reshape function non-existent
2003  * - degraded set
2004  * - ongoing recovery
2005  * - ongoing reshape
2006  *
2007  * Returns 0 if none or -EPERM if given constraint
2008  * and error message reference in @errmsg
2009  */
2010 static int rs_check_reshape(struct raid_set *rs)
2011 {
2012 	struct mddev *mddev = &rs->md;
2013 
2014 	if (!mddev->pers || !mddev->pers->check_reshape)
2015 		rs->ti->error = "Reshape not supported";
2016 	else if (mddev->degraded)
2017 		rs->ti->error = "Can't reshape degraded raid set";
2018 	else if (rs_is_recovering(rs))
2019 		rs->ti->error = "Convert request on recovering raid set prohibited";
2020 	else if (rs_is_reshaping(rs))
2021 		rs->ti->error = "raid set already reshaping!";
2022 	else if (!(rs_is_raid1(rs) || rs_is_raid10(rs) || rs_is_raid456(rs)))
2023 		rs->ti->error = "Reshaping only supported for raid1/4/5/6/10";
2024 	else
2025 		return 0;
2026 
2027 	return -EPERM;
2028 }
2029 
2030 static int read_disk_sb(struct md_rdev *rdev, int size, bool force_reload)
2031 {
2032 	BUG_ON(!rdev->sb_page);
2033 
2034 	if (rdev->sb_loaded && !force_reload)
2035 		return 0;
2036 
2037 	rdev->sb_loaded = 0;
2038 
2039 	if (!sync_page_io(rdev, 0, size, rdev->sb_page, REQ_OP_READ, 0, true)) {
2040 		DMERR("Failed to read superblock of device at position %d",
2041 		      rdev->raid_disk);
2042 		md_error(rdev->mddev, rdev);
2043 		set_bit(Faulty, &rdev->flags);
2044 		return -EIO;
2045 	}
2046 
2047 	rdev->sb_loaded = 1;
2048 
2049 	return 0;
2050 }
2051 
2052 static void sb_retrieve_failed_devices(struct dm_raid_superblock *sb, uint64_t *failed_devices)
2053 {
2054 	failed_devices[0] = le64_to_cpu(sb->failed_devices);
2055 	memset(failed_devices + 1, 0, sizeof(sb->extended_failed_devices));
2056 
2057 	if (le32_to_cpu(sb->compat_features) & FEATURE_FLAG_SUPPORTS_V190) {
2058 		int i = ARRAY_SIZE(sb->extended_failed_devices);
2059 
2060 		while (i--)
2061 			failed_devices[i+1] = le64_to_cpu(sb->extended_failed_devices[i]);
2062 	}
2063 }
2064 
2065 static void sb_update_failed_devices(struct dm_raid_superblock *sb, uint64_t *failed_devices)
2066 {
2067 	int i = ARRAY_SIZE(sb->extended_failed_devices);
2068 
2069 	sb->failed_devices = cpu_to_le64(failed_devices[0]);
2070 	while (i--)
2071 		sb->extended_failed_devices[i] = cpu_to_le64(failed_devices[i+1]);
2072 }
2073 
2074 /*
2075  * Synchronize the superblock members with the raid set properties
2076  *
2077  * All superblock data is little endian.
2078  */
2079 static void super_sync(struct mddev *mddev, struct md_rdev *rdev)
2080 {
2081 	bool update_failed_devices = false;
2082 	unsigned int i;
2083 	uint64_t failed_devices[DISKS_ARRAY_ELEMS];
2084 	struct dm_raid_superblock *sb;
2085 	struct raid_set *rs = container_of(mddev, struct raid_set, md);
2086 
2087 	/* No metadata device, no superblock */
2088 	if (!rdev->meta_bdev)
2089 		return;
2090 
2091 	BUG_ON(!rdev->sb_page);
2092 
2093 	sb = page_address(rdev->sb_page);
2094 
2095 	sb_retrieve_failed_devices(sb, failed_devices);
2096 
2097 	for (i = 0; i < rs->raid_disks; i++)
2098 		if (!rs->dev[i].data_dev || test_bit(Faulty, &rs->dev[i].rdev.flags)) {
2099 			update_failed_devices = true;
2100 			set_bit(i, (void *) failed_devices);
2101 		}
2102 
2103 	if (update_failed_devices)
2104 		sb_update_failed_devices(sb, failed_devices);
2105 
2106 	sb->magic = cpu_to_le32(DM_RAID_MAGIC);
2107 	sb->compat_features = cpu_to_le32(FEATURE_FLAG_SUPPORTS_V190);
2108 
2109 	sb->num_devices = cpu_to_le32(mddev->raid_disks);
2110 	sb->array_position = cpu_to_le32(rdev->raid_disk);
2111 
2112 	sb->events = cpu_to_le64(mddev->events);
2113 
2114 	sb->disk_recovery_offset = cpu_to_le64(rdev->recovery_offset);
2115 	sb->array_resync_offset = cpu_to_le64(mddev->recovery_cp);
2116 
2117 	sb->level = cpu_to_le32(mddev->level);
2118 	sb->layout = cpu_to_le32(mddev->layout);
2119 	sb->stripe_sectors = cpu_to_le32(mddev->chunk_sectors);
2120 
2121 	/********************************************************************
2122 	 * BELOW FOLLOW V1.9.0 EXTENSIONS TO THE PRISTINE SUPERBLOCK FORMAT!!!
2123 	 *
2124 	 * FEATURE_FLAG_SUPPORTS_V190 in the compat_features member indicates that those exist
2125 	 */
2126 	sb->new_level = cpu_to_le32(mddev->new_level);
2127 	sb->new_layout = cpu_to_le32(mddev->new_layout);
2128 	sb->new_stripe_sectors = cpu_to_le32(mddev->new_chunk_sectors);
2129 
2130 	sb->delta_disks = cpu_to_le32(mddev->delta_disks);
2131 
2132 	smp_rmb(); /* Make sure we access most recent reshape position */
2133 	sb->reshape_position = cpu_to_le64(mddev->reshape_position);
2134 	if (le64_to_cpu(sb->reshape_position) != MaxSector) {
2135 		/* Flag ongoing reshape */
2136 		sb->flags |= cpu_to_le32(SB_FLAG_RESHAPE_ACTIVE);
2137 
2138 		if (mddev->delta_disks < 0 || mddev->reshape_backwards)
2139 			sb->flags |= cpu_to_le32(SB_FLAG_RESHAPE_BACKWARDS);
2140 	} else {
2141 		/* Clear reshape flags */
2142 		sb->flags &= ~(cpu_to_le32(SB_FLAG_RESHAPE_ACTIVE|SB_FLAG_RESHAPE_BACKWARDS));
2143 	}
2144 
2145 	sb->array_sectors = cpu_to_le64(mddev->array_sectors);
2146 	sb->data_offset = cpu_to_le64(rdev->data_offset);
2147 	sb->new_data_offset = cpu_to_le64(rdev->new_data_offset);
2148 	sb->sectors = cpu_to_le64(rdev->sectors);
2149 	sb->incompat_features = cpu_to_le32(0);
2150 
2151 	/* Zero out the rest of the payload after the size of the superblock */
2152 	memset(sb + 1, 0, rdev->sb_size - sizeof(*sb));
2153 }
2154 
2155 /*
2156  * super_load
2157  *
2158  * This function creates a superblock if one is not found on the device
2159  * and will decide which superblock to use if there's a choice.
2160  *
2161  * Return: 1 if use rdev, 0 if use refdev, -Exxx otherwise
2162  */
2163 static int super_load(struct md_rdev *rdev, struct md_rdev *refdev)
2164 {
2165 	int r;
2166 	struct dm_raid_superblock *sb;
2167 	struct dm_raid_superblock *refsb;
2168 	uint64_t events_sb, events_refsb;
2169 
2170 	r = read_disk_sb(rdev, rdev->sb_size, false);
2171 	if (r)
2172 		return r;
2173 
2174 	sb = page_address(rdev->sb_page);
2175 
2176 	/*
2177 	 * Two cases that we want to write new superblocks and rebuild:
2178 	 * 1) New device (no matching magic number)
2179 	 * 2) Device specified for rebuild (!In_sync w/ offset == 0)
2180 	 */
2181 	if ((sb->magic != cpu_to_le32(DM_RAID_MAGIC)) ||
2182 	    (!test_bit(In_sync, &rdev->flags) && !rdev->recovery_offset)) {
2183 		super_sync(rdev->mddev, rdev);
2184 
2185 		set_bit(FirstUse, &rdev->flags);
2186 		sb->compat_features = cpu_to_le32(FEATURE_FLAG_SUPPORTS_V190);
2187 
2188 		/* Force writing of superblocks to disk */
2189 		set_bit(MD_SB_CHANGE_DEVS, &rdev->mddev->sb_flags);
2190 
2191 		/* Any superblock is better than none, choose that if given */
2192 		return refdev ? 0 : 1;
2193 	}
2194 
2195 	if (!refdev)
2196 		return 1;
2197 
2198 	events_sb = le64_to_cpu(sb->events);
2199 
2200 	refsb = page_address(refdev->sb_page);
2201 	events_refsb = le64_to_cpu(refsb->events);
2202 
2203 	return (events_sb > events_refsb) ? 1 : 0;
2204 }
2205 
2206 static int super_init_validation(struct raid_set *rs, struct md_rdev *rdev)
2207 {
2208 	int role;
2209 	unsigned int d;
2210 	struct mddev *mddev = &rs->md;
2211 	uint64_t events_sb;
2212 	uint64_t failed_devices[DISKS_ARRAY_ELEMS];
2213 	struct dm_raid_superblock *sb;
2214 	uint32_t new_devs = 0, rebuild_and_new = 0, rebuilds = 0;
2215 	struct md_rdev *r;
2216 	struct dm_raid_superblock *sb2;
2217 
2218 	sb = page_address(rdev->sb_page);
2219 	events_sb = le64_to_cpu(sb->events);
2220 
2221 	/*
2222 	 * Initialise to 1 if this is a new superblock.
2223 	 */
2224 	mddev->events = events_sb ? : 1;
2225 
2226 	mddev->reshape_position = MaxSector;
2227 
2228 	mddev->raid_disks = le32_to_cpu(sb->num_devices);
2229 	mddev->level = le32_to_cpu(sb->level);
2230 	mddev->layout = le32_to_cpu(sb->layout);
2231 	mddev->chunk_sectors = le32_to_cpu(sb->stripe_sectors);
2232 
2233 	/*
2234 	 * Reshaping is supported, e.g. reshape_position is valid
2235 	 * in superblock and superblock content is authoritative.
2236 	 */
2237 	if (le32_to_cpu(sb->compat_features) & FEATURE_FLAG_SUPPORTS_V190) {
2238 		/* Superblock is authoritative wrt given raid set layout! */
2239 		mddev->new_level = le32_to_cpu(sb->new_level);
2240 		mddev->new_layout = le32_to_cpu(sb->new_layout);
2241 		mddev->new_chunk_sectors = le32_to_cpu(sb->new_stripe_sectors);
2242 		mddev->delta_disks = le32_to_cpu(sb->delta_disks);
2243 		mddev->array_sectors = le64_to_cpu(sb->array_sectors);
2244 
2245 		/* raid was reshaping and got interrupted */
2246 		if (le32_to_cpu(sb->flags) & SB_FLAG_RESHAPE_ACTIVE) {
2247 			if (test_bit(__CTR_FLAG_DELTA_DISKS, &rs->ctr_flags)) {
2248 				DMERR("Reshape requested but raid set is still reshaping");
2249 				return -EINVAL;
2250 			}
2251 
2252 			if (mddev->delta_disks < 0 ||
2253 			    (!mddev->delta_disks && (le32_to_cpu(sb->flags) & SB_FLAG_RESHAPE_BACKWARDS)))
2254 				mddev->reshape_backwards = 1;
2255 			else
2256 				mddev->reshape_backwards = 0;
2257 
2258 			mddev->reshape_position = le64_to_cpu(sb->reshape_position);
2259 			rs->raid_type = get_raid_type_by_ll(mddev->level, mddev->layout);
2260 		}
2261 
2262 	} else {
2263 		/*
2264 		 * No takeover/reshaping, because we don't have the extended v1.9.0 metadata
2265 		 */
2266 		struct raid_type *rt_cur = get_raid_type_by_ll(mddev->level, mddev->layout);
2267 		struct raid_type *rt_new = get_raid_type_by_ll(mddev->new_level, mddev->new_layout);
2268 
2269 		if (rs_takeover_requested(rs)) {
2270 			if (rt_cur && rt_new)
2271 				DMERR("Takeover raid sets from %s to %s not yet supported by metadata. (raid level change)",
2272 				      rt_cur->name, rt_new->name);
2273 			else
2274 				DMERR("Takeover raid sets not yet supported by metadata. (raid level change)");
2275 			return -EINVAL;
2276 		} else if (rs_reshape_requested(rs)) {
2277 			DMERR("Reshaping raid sets not yet supported by metadata. (raid layout change keeping level)");
2278 			if (mddev->layout != mddev->new_layout) {
2279 				if (rt_cur && rt_new)
2280 					DMERR("	 current layout %s vs new layout %s",
2281 					      rt_cur->name, rt_new->name);
2282 				else
2283 					DMERR("	 current layout 0x%X vs new layout 0x%X",
2284 					      le32_to_cpu(sb->layout), mddev->new_layout);
2285 			}
2286 			if (mddev->chunk_sectors != mddev->new_chunk_sectors)
2287 				DMERR("	 current stripe sectors %u vs new stripe sectors %u",
2288 				      mddev->chunk_sectors, mddev->new_chunk_sectors);
2289 			if (rs->delta_disks)
2290 				DMERR("	 current %u disks vs new %u disks",
2291 				      mddev->raid_disks, mddev->raid_disks + rs->delta_disks);
2292 			if (rs_is_raid10(rs)) {
2293 				DMERR("	 Old layout: %s w/ %u copies",
2294 				      raid10_md_layout_to_format(mddev->layout),
2295 				      raid10_md_layout_to_copies(mddev->layout));
2296 				DMERR("	 New layout: %s w/ %u copies",
2297 				      raid10_md_layout_to_format(mddev->new_layout),
2298 				      raid10_md_layout_to_copies(mddev->new_layout));
2299 			}
2300 			return -EINVAL;
2301 		}
2302 
2303 		DMINFO("Discovered old metadata format; upgrading to extended metadata format");
2304 	}
2305 
2306 	if (!test_bit(__CTR_FLAG_NOSYNC, &rs->ctr_flags))
2307 		mddev->recovery_cp = le64_to_cpu(sb->array_resync_offset);
2308 
2309 	/*
2310 	 * During load, we set FirstUse if a new superblock was written.
2311 	 * There are two reasons we might not have a superblock:
2312 	 * 1) The raid set is brand new - in which case, all of the
2313 	 *    devices must have their In_sync bit set.	Also,
2314 	 *    recovery_cp must be 0, unless forced.
2315 	 * 2) This is a new device being added to an old raid set
2316 	 *    and the new device needs to be rebuilt - in which
2317 	 *    case the In_sync bit will /not/ be set and
2318 	 *    recovery_cp must be MaxSector.
2319 	 * 3) This is/are a new device(s) being added to an old
2320 	 *    raid set during takeover to a higher raid level
2321 	 *    to provide capacity for redundancy or during reshape
2322 	 *    to add capacity to grow the raid set.
2323 	 */
2324 	d = 0;
2325 	rdev_for_each(r, mddev) {
2326 		if (test_bit(Journal, &rdev->flags))
2327 			continue;
2328 
2329 		if (test_bit(FirstUse, &r->flags))
2330 			new_devs++;
2331 
2332 		if (!test_bit(In_sync, &r->flags)) {
2333 			DMINFO("Device %d specified for rebuild; clearing superblock",
2334 				r->raid_disk);
2335 			rebuilds++;
2336 
2337 			if (test_bit(FirstUse, &r->flags))
2338 				rebuild_and_new++;
2339 		}
2340 
2341 		d++;
2342 	}
2343 
2344 	if (new_devs == rs->raid_disks || !rebuilds) {
2345 		/* Replace a broken device */
2346 		if (new_devs == rs->raid_disks) {
2347 			DMINFO("Superblocks created for new raid set");
2348 			set_bit(MD_ARRAY_FIRST_USE, &mddev->flags);
2349 		} else if (new_devs != rebuilds &&
2350 			   new_devs != rs->delta_disks) {
2351 			DMERR("New device injected into existing raid set without "
2352 			      "'delta_disks' or 'rebuild' parameter specified");
2353 			return -EINVAL;
2354 		}
2355 	} else if (new_devs && new_devs != rebuilds) {
2356 		DMERR("%u 'rebuild' devices cannot be injected into"
2357 		      " a raid set with %u other first-time devices",
2358 		      rebuilds, new_devs);
2359 		return -EINVAL;
2360 	} else if (rebuilds) {
2361 		if (rebuild_and_new && rebuilds != rebuild_and_new) {
2362 			DMERR("new device%s provided without 'rebuild'",
2363 			      new_devs > 1 ? "s" : "");
2364 			return -EINVAL;
2365 		} else if (!test_bit(__CTR_FLAG_REBUILD, &rs->ctr_flags) && rs_is_recovering(rs)) {
2366 			DMERR("'rebuild' specified while raid set is not in-sync (recovery_cp=%llu)",
2367 			      (unsigned long long) mddev->recovery_cp);
2368 			return -EINVAL;
2369 		} else if (rs_is_reshaping(rs)) {
2370 			DMERR("'rebuild' specified while raid set is being reshaped (reshape_position=%llu)",
2371 			      (unsigned long long) mddev->reshape_position);
2372 			return -EINVAL;
2373 		}
2374 	}
2375 
2376 	/*
2377 	 * Now we set the Faulty bit for those devices that are
2378 	 * recorded in the superblock as failed.
2379 	 */
2380 	sb_retrieve_failed_devices(sb, failed_devices);
2381 	rdev_for_each(r, mddev) {
2382 		if (test_bit(Journal, &rdev->flags) ||
2383 		    !r->sb_page)
2384 			continue;
2385 		sb2 = page_address(r->sb_page);
2386 		sb2->failed_devices = 0;
2387 		memset(sb2->extended_failed_devices, 0, sizeof(sb2->extended_failed_devices));
2388 
2389 		/*
2390 		 * Check for any device re-ordering.
2391 		 */
2392 		if (!test_bit(FirstUse, &r->flags) && (r->raid_disk >= 0)) {
2393 			role = le32_to_cpu(sb2->array_position);
2394 			if (role < 0)
2395 				continue;
2396 
2397 			if (role != r->raid_disk) {
2398 				if (rs_is_raid10(rs) && __is_raid10_near(mddev->layout)) {
2399 					if (mddev->raid_disks % __raid10_near_copies(mddev->layout) ||
2400 					    rs->raid_disks % rs->raid10_copies) {
2401 						rs->ti->error =
2402 							"Cannot change raid10 near set to odd # of devices!";
2403 						return -EINVAL;
2404 					}
2405 
2406 					sb2->array_position = cpu_to_le32(r->raid_disk);
2407 
2408 				} else if (!(rs_is_raid10(rs) && rt_is_raid0(rs->raid_type)) &&
2409 					   !(rs_is_raid0(rs) && rt_is_raid10(rs->raid_type)) &&
2410 					   !rt_is_raid1(rs->raid_type)) {
2411 					rs->ti->error = "Cannot change device positions in raid set";
2412 					return -EINVAL;
2413 				}
2414 
2415 				DMINFO("raid device #%d now at position #%d", role, r->raid_disk);
2416 			}
2417 
2418 			/*
2419 			 * Partial recovery is performed on
2420 			 * returning failed devices.
2421 			 */
2422 			if (test_bit(role, (void *) failed_devices))
2423 				set_bit(Faulty, &r->flags);
2424 		}
2425 	}
2426 
2427 	return 0;
2428 }
2429 
2430 static int super_validate(struct raid_set *rs, struct md_rdev *rdev)
2431 {
2432 	struct mddev *mddev = &rs->md;
2433 	struct dm_raid_superblock *sb;
2434 
2435 	if (rs_is_raid0(rs) || !rdev->sb_page || rdev->raid_disk < 0)
2436 		return 0;
2437 
2438 	sb = page_address(rdev->sb_page);
2439 
2440 	/*
2441 	 * If mddev->events is not set, we know we have not yet initialized
2442 	 * the array.
2443 	 */
2444 	if (!mddev->events && super_init_validation(rs, rdev))
2445 		return -EINVAL;
2446 
2447 	if (le32_to_cpu(sb->compat_features) &&
2448 	    le32_to_cpu(sb->compat_features) != FEATURE_FLAG_SUPPORTS_V190) {
2449 		rs->ti->error = "Unable to assemble array: Unknown flag(s) in compatible feature flags";
2450 		return -EINVAL;
2451 	}
2452 
2453 	if (sb->incompat_features) {
2454 		rs->ti->error = "Unable to assemble array: No incompatible feature flags supported yet";
2455 		return -EINVAL;
2456 	}
2457 
2458 	/* Enable bitmap creation on @rs unless no metadevs or raid0 or journaled raid4/5/6 set. */
2459 	mddev->bitmap_info.offset = (rt_is_raid0(rs->raid_type) || rs->journal_dev.dev) ? 0 : to_sector(4096);
2460 	mddev->bitmap_info.default_offset = mddev->bitmap_info.offset;
2461 
2462 	if (!test_and_clear_bit(FirstUse, &rdev->flags)) {
2463 		/*
2464 		 * Retrieve rdev size stored in superblock to be prepared for shrink.
2465 		 * Check extended superblock members are present otherwise the size
2466 		 * will not be set!
2467 		 */
2468 		if (le32_to_cpu(sb->compat_features) & FEATURE_FLAG_SUPPORTS_V190)
2469 			rdev->sectors = le64_to_cpu(sb->sectors);
2470 
2471 		rdev->recovery_offset = le64_to_cpu(sb->disk_recovery_offset);
2472 		if (rdev->recovery_offset == MaxSector)
2473 			set_bit(In_sync, &rdev->flags);
2474 		/*
2475 		 * If no reshape in progress -> we're recovering single
2476 		 * disk(s) and have to set the device(s) to out-of-sync
2477 		 */
2478 		else if (!rs_is_reshaping(rs))
2479 			clear_bit(In_sync, &rdev->flags); /* Mandatory for recovery */
2480 	}
2481 
2482 	/*
2483 	 * If a device comes back, set it as not In_sync and no longer faulty.
2484 	 */
2485 	if (test_and_clear_bit(Faulty, &rdev->flags)) {
2486 		rdev->recovery_offset = 0;
2487 		clear_bit(In_sync, &rdev->flags);
2488 		rdev->saved_raid_disk = rdev->raid_disk;
2489 	}
2490 
2491 	/* Reshape support -> restore repective data offsets */
2492 	rdev->data_offset = le64_to_cpu(sb->data_offset);
2493 	rdev->new_data_offset = le64_to_cpu(sb->new_data_offset);
2494 
2495 	return 0;
2496 }
2497 
2498 /*
2499  * Analyse superblocks and select the freshest.
2500  */
2501 static int analyse_superblocks(struct dm_target *ti, struct raid_set *rs)
2502 {
2503 	int r;
2504 	struct md_rdev *rdev, *freshest;
2505 	struct mddev *mddev = &rs->md;
2506 
2507 	freshest = NULL;
2508 	rdev_for_each(rdev, mddev) {
2509 		if (test_bit(Journal, &rdev->flags))
2510 			continue;
2511 
2512 		if (!rdev->meta_bdev)
2513 			continue;
2514 
2515 		/* Set superblock offset/size for metadata device. */
2516 		rdev->sb_start = 0;
2517 		rdev->sb_size = bdev_logical_block_size(rdev->meta_bdev);
2518 		if (rdev->sb_size < sizeof(struct dm_raid_superblock) || rdev->sb_size > PAGE_SIZE) {
2519 			DMERR("superblock size of a logical block is no longer valid");
2520 			return -EINVAL;
2521 		}
2522 
2523 		/*
2524 		 * Skipping super_load due to CTR_FLAG_SYNC will cause
2525 		 * the array to undergo initialization again as
2526 		 * though it were new.	This is the intended effect
2527 		 * of the "sync" directive.
2528 		 *
2529 		 * With reshaping capability added, we must ensure that
2530 		 * that the "sync" directive is disallowed during the reshape.
2531 		 */
2532 		if (test_bit(__CTR_FLAG_SYNC, &rs->ctr_flags))
2533 			continue;
2534 
2535 		r = super_load(rdev, freshest);
2536 
2537 		switch (r) {
2538 		case 1:
2539 			freshest = rdev;
2540 			break;
2541 		case 0:
2542 			break;
2543 		default:
2544 			/* This is a failure to read the superblock from the metadata device. */
2545 			/*
2546 			 * We have to keep any raid0 data/metadata device pairs or
2547 			 * the MD raid0 personality will fail to start the array.
2548 			 */
2549 			if (rs_is_raid0(rs))
2550 				continue;
2551 
2552 			/*
2553 			 * We keep the dm_devs to be able to emit the device tuple
2554 			 * properly on the table line in raid_status() (rather than
2555 			 * mistakenly acting as if '- -' got passed into the constructor).
2556 			 *
2557 			 * The rdev has to stay on the same_set list to allow for
2558 			 * the attempt to restore faulty devices on second resume.
2559 			 */
2560 			rdev->raid_disk = rdev->saved_raid_disk = -1;
2561 			break;
2562 		}
2563 	}
2564 
2565 	if (!freshest)
2566 		return 0;
2567 
2568 	/*
2569 	 * Validation of the freshest device provides the source of
2570 	 * validation for the remaining devices.
2571 	 */
2572 	rs->ti->error = "Unable to assemble array: Invalid superblocks";
2573 	if (super_validate(rs, freshest))
2574 		return -EINVAL;
2575 
2576 	if (validate_raid_redundancy(rs)) {
2577 		rs->ti->error = "Insufficient redundancy to activate array";
2578 		return -EINVAL;
2579 	}
2580 
2581 	rdev_for_each(rdev, mddev)
2582 		if (!test_bit(Journal, &rdev->flags) &&
2583 		    rdev != freshest &&
2584 		    super_validate(rs, rdev))
2585 			return -EINVAL;
2586 	return 0;
2587 }
2588 
2589 /*
2590  * Adjust data_offset and new_data_offset on all disk members of @rs
2591  * for out of place reshaping if requested by contructor
2592  *
2593  * We need free space at the beginning of each raid disk for forward
2594  * and at the end for backward reshapes which userspace has to provide
2595  * via remapping/reordering of space.
2596  */
2597 static int rs_adjust_data_offsets(struct raid_set *rs)
2598 {
2599 	sector_t data_offset = 0, new_data_offset = 0;
2600 	struct md_rdev *rdev;
2601 
2602 	/* Constructor did not request data offset change */
2603 	if (!test_bit(__CTR_FLAG_DATA_OFFSET, &rs->ctr_flags)) {
2604 		if (!rs_is_reshapable(rs))
2605 			goto out;
2606 
2607 		return 0;
2608 	}
2609 
2610 	/* HM FIXME: get In_Sync raid_dev? */
2611 	rdev = &rs->dev[0].rdev;
2612 
2613 	if (rs->delta_disks < 0) {
2614 		/*
2615 		 * Removing disks (reshaping backwards):
2616 		 *
2617 		 * - before reshape: data is at offset 0 and free space
2618 		 *		     is at end of each component LV
2619 		 *
2620 		 * - after reshape: data is at offset rs->data_offset != 0 on each component LV
2621 		 */
2622 		data_offset = 0;
2623 		new_data_offset = rs->data_offset;
2624 
2625 	} else if (rs->delta_disks > 0) {
2626 		/*
2627 		 * Adding disks (reshaping forwards):
2628 		 *
2629 		 * - before reshape: data is at offset rs->data_offset != 0 and
2630 		 *		     free space is at begin of each component LV
2631 		 *
2632 		 * - after reshape: data is at offset 0 on each component LV
2633 		 */
2634 		data_offset = rs->data_offset;
2635 		new_data_offset = 0;
2636 
2637 	} else {
2638 		/*
2639 		 * User space passes in 0 for data offset after having removed reshape space
2640 		 *
2641 		 * - or - (data offset != 0)
2642 		 *
2643 		 * Changing RAID layout or chunk size -> toggle offsets
2644 		 *
2645 		 * - before reshape: data is at offset rs->data_offset 0 and
2646 		 *		     free space is at end of each component LV
2647 		 *		     -or-
2648 		 *                   data is at offset rs->data_offset != 0 and
2649 		 *		     free space is at begin of each component LV
2650 		 *
2651 		 * - after reshape: data is at offset 0 if it was at offset != 0
2652 		 *                  or at offset != 0 if it was at offset 0
2653 		 *                  on each component LV
2654 		 *
2655 		 */
2656 		data_offset = rs->data_offset ? rdev->data_offset : 0;
2657 		new_data_offset = data_offset ? 0 : rs->data_offset;
2658 		set_bit(RT_FLAG_UPDATE_SBS, &rs->runtime_flags);
2659 	}
2660 
2661 	/*
2662 	 * Make sure we got a minimum amount of free sectors per device
2663 	 */
2664 	if (rs->data_offset &&
2665 	    to_sector(i_size_read(rdev->bdev->bd_inode)) - rs->md.dev_sectors < MIN_FREE_RESHAPE_SPACE) {
2666 		rs->ti->error = data_offset ? "No space for forward reshape" :
2667 					      "No space for backward reshape";
2668 		return -ENOSPC;
2669 	}
2670 out:
2671 	/*
2672 	 * Raise recovery_cp in case data_offset != 0 to
2673 	 * avoid false recovery positives in the constructor.
2674 	 */
2675 	if (rs->md.recovery_cp < rs->md.dev_sectors)
2676 		rs->md.recovery_cp += rs->dev[0].rdev.data_offset;
2677 
2678 	/* Adjust data offsets on all rdevs but on any raid4/5/6 journal device */
2679 	rdev_for_each(rdev, &rs->md) {
2680 		if (!test_bit(Journal, &rdev->flags)) {
2681 			rdev->data_offset = data_offset;
2682 			rdev->new_data_offset = new_data_offset;
2683 		}
2684 	}
2685 
2686 	return 0;
2687 }
2688 
2689 /* Userpace reordered disks -> adjust raid_disk indexes in @rs */
2690 static void __reorder_raid_disk_indexes(struct raid_set *rs)
2691 {
2692 	int i = 0;
2693 	struct md_rdev *rdev;
2694 
2695 	rdev_for_each(rdev, &rs->md) {
2696 		if (!test_bit(Journal, &rdev->flags)) {
2697 			rdev->raid_disk = i++;
2698 			rdev->saved_raid_disk = rdev->new_raid_disk = -1;
2699 		}
2700 	}
2701 }
2702 
2703 /*
2704  * Setup @rs for takeover by a different raid level
2705  */
2706 static int rs_setup_takeover(struct raid_set *rs)
2707 {
2708 	struct mddev *mddev = &rs->md;
2709 	struct md_rdev *rdev;
2710 	unsigned int d = mddev->raid_disks = rs->raid_disks;
2711 	sector_t new_data_offset = rs->dev[0].rdev.data_offset ? 0 : rs->data_offset;
2712 
2713 	if (rt_is_raid10(rs->raid_type)) {
2714 		if (rs_is_raid0(rs)) {
2715 			/* Userpace reordered disks -> adjust raid_disk indexes */
2716 			__reorder_raid_disk_indexes(rs);
2717 
2718 			/* raid0 -> raid10_far layout */
2719 			mddev->layout = raid10_format_to_md_layout(rs, ALGORITHM_RAID10_FAR,
2720 								   rs->raid10_copies);
2721 		} else if (rs_is_raid1(rs))
2722 			/* raid1 -> raid10_near layout */
2723 			mddev->layout = raid10_format_to_md_layout(rs, ALGORITHM_RAID10_NEAR,
2724 								   rs->raid_disks);
2725 		else
2726 			return -EINVAL;
2727 
2728 	}
2729 
2730 	clear_bit(MD_ARRAY_FIRST_USE, &mddev->flags);
2731 	mddev->recovery_cp = MaxSector;
2732 
2733 	while (d--) {
2734 		rdev = &rs->dev[d].rdev;
2735 
2736 		if (test_bit(d, (void *) rs->rebuild_disks)) {
2737 			clear_bit(In_sync, &rdev->flags);
2738 			clear_bit(Faulty, &rdev->flags);
2739 			mddev->recovery_cp = rdev->recovery_offset = 0;
2740 			/* Bitmap has to be created when we do an "up" takeover */
2741 			set_bit(MD_ARRAY_FIRST_USE, &mddev->flags);
2742 		}
2743 
2744 		rdev->new_data_offset = new_data_offset;
2745 	}
2746 
2747 	return 0;
2748 }
2749 
2750 /* Prepare @rs for reshape */
2751 static int rs_prepare_reshape(struct raid_set *rs)
2752 {
2753 	bool reshape;
2754 	struct mddev *mddev = &rs->md;
2755 
2756 	if (rs_is_raid10(rs)) {
2757 		if (rs->raid_disks != mddev->raid_disks &&
2758 		    __is_raid10_near(mddev->layout) &&
2759 		    rs->raid10_copies &&
2760 		    rs->raid10_copies != __raid10_near_copies(mddev->layout)) {
2761 			/*
2762 			 * raid disk have to be multiple of data copies to allow this conversion,
2763 			 *
2764 			 * This is actually not a reshape it is a
2765 			 * rebuild of any additional mirrors per group
2766 			 */
2767 			if (rs->raid_disks % rs->raid10_copies) {
2768 				rs->ti->error = "Can't reshape raid10 mirror groups";
2769 				return -EINVAL;
2770 			}
2771 
2772 			/* Userpace reordered disks to add/remove mirrors -> adjust raid_disk indexes */
2773 			__reorder_raid_disk_indexes(rs);
2774 			mddev->layout = raid10_format_to_md_layout(rs, ALGORITHM_RAID10_NEAR,
2775 								   rs->raid10_copies);
2776 			mddev->new_layout = mddev->layout;
2777 			reshape = false;
2778 		} else
2779 			reshape = true;
2780 
2781 	} else if (rs_is_raid456(rs))
2782 		reshape = true;
2783 
2784 	else if (rs_is_raid1(rs)) {
2785 		if (rs->delta_disks) {
2786 			/* Process raid1 via delta_disks */
2787 			mddev->degraded = rs->delta_disks < 0 ? -rs->delta_disks : rs->delta_disks;
2788 			reshape = true;
2789 		} else {
2790 			/* Process raid1 without delta_disks */
2791 			mddev->raid_disks = rs->raid_disks;
2792 			reshape = false;
2793 		}
2794 	} else {
2795 		rs->ti->error = "Called with bogus raid type";
2796 		return -EINVAL;
2797 	}
2798 
2799 	if (reshape) {
2800 		set_bit(RT_FLAG_RESHAPE_RS, &rs->runtime_flags);
2801 		set_bit(RT_FLAG_UPDATE_SBS, &rs->runtime_flags);
2802 	} else if (mddev->raid_disks < rs->raid_disks)
2803 		/* Create new superblocks and bitmaps, if any new disks */
2804 		set_bit(RT_FLAG_UPDATE_SBS, &rs->runtime_flags);
2805 
2806 	return 0;
2807 }
2808 
2809 /* Get reshape sectors from data_offsets or raid set */
2810 static sector_t _get_reshape_sectors(struct raid_set *rs)
2811 {
2812 	struct md_rdev *rdev;
2813 	sector_t reshape_sectors = 0;
2814 
2815 	rdev_for_each(rdev, &rs->md)
2816 		if (!test_bit(Journal, &rdev->flags)) {
2817 			reshape_sectors = (rdev->data_offset > rdev->new_data_offset) ?
2818 					rdev->data_offset - rdev->new_data_offset :
2819 					rdev->new_data_offset - rdev->data_offset;
2820 			break;
2821 		}
2822 
2823 	return max(reshape_sectors, (sector_t) rs->data_offset);
2824 }
2825 
2826 /*
2827  * Reshape:
2828  * - change raid layout
2829  * - change chunk size
2830  * - add disks
2831  * - remove disks
2832  */
2833 static int rs_setup_reshape(struct raid_set *rs)
2834 {
2835 	int r = 0;
2836 	unsigned int cur_raid_devs, d;
2837 	sector_t reshape_sectors = _get_reshape_sectors(rs);
2838 	struct mddev *mddev = &rs->md;
2839 	struct md_rdev *rdev;
2840 
2841 	mddev->delta_disks = rs->delta_disks;
2842 	cur_raid_devs = mddev->raid_disks;
2843 
2844 	/* Ignore impossible layout change whilst adding/removing disks */
2845 	if (mddev->delta_disks &&
2846 	    mddev->layout != mddev->new_layout) {
2847 		DMINFO("Ignoring invalid layout change with delta_disks=%d", rs->delta_disks);
2848 		mddev->new_layout = mddev->layout;
2849 	}
2850 
2851 	/*
2852 	 * Adjust array size:
2853 	 *
2854 	 * - in case of adding disk(s), array size has
2855 	 *   to grow after the disk adding reshape,
2856 	 *   which'll hapen in the event handler;
2857 	 *   reshape will happen forward, so space has to
2858 	 *   be available at the beginning of each disk
2859 	 *
2860 	 * - in case of removing disk(s), array size
2861 	 *   has to shrink before starting the reshape,
2862 	 *   which'll happen here;
2863 	 *   reshape will happen backward, so space has to
2864 	 *   be available at the end of each disk
2865 	 *
2866 	 * - data_offset and new_data_offset are
2867 	 *   adjusted for aforementioned out of place
2868 	 *   reshaping based on userspace passing in
2869 	 *   the "data_offset <sectors>" key/value
2870 	 *   pair via the constructor
2871 	 */
2872 
2873 	/* Add disk(s) */
2874 	if (rs->delta_disks > 0) {
2875 		/* Prepare disks for check in raid4/5/6/10 {check|start}_reshape */
2876 		for (d = cur_raid_devs; d < rs->raid_disks; d++) {
2877 			rdev = &rs->dev[d].rdev;
2878 			clear_bit(In_sync, &rdev->flags);
2879 
2880 			/*
2881 			 * save_raid_disk needs to be -1, or recovery_offset will be set to 0
2882 			 * by md, which'll store that erroneously in the superblock on reshape
2883 			 */
2884 			rdev->saved_raid_disk = -1;
2885 			rdev->raid_disk = d;
2886 
2887 			rdev->sectors = mddev->dev_sectors;
2888 			rdev->recovery_offset = rs_is_raid1(rs) ? 0 : MaxSector;
2889 		}
2890 
2891 		mddev->reshape_backwards = 0; /* adding disk(s) -> forward reshape */
2892 
2893 	/* Remove disk(s) */
2894 	} else if (rs->delta_disks < 0) {
2895 		r = rs_set_dev_and_array_sectors(rs, rs->ti->len, true);
2896 		mddev->reshape_backwards = 1; /* removing disk(s) -> backward reshape */
2897 
2898 	/* Change layout and/or chunk size */
2899 	} else {
2900 		/*
2901 		 * Reshape layout (e.g. raid5_ls -> raid5_n) and/or chunk size:
2902 		 *
2903 		 * keeping number of disks and do layout change ->
2904 		 *
2905 		 * toggle reshape_backward depending on data_offset:
2906 		 *
2907 		 * - free space upfront -> reshape forward
2908 		 *
2909 		 * - free space at the end -> reshape backward
2910 		 *
2911 		 *
2912 		 * This utilizes free reshape space avoiding the need
2913 		 * for userspace to move (parts of) LV segments in
2914 		 * case of layout/chunksize change  (for disk
2915 		 * adding/removing reshape space has to be at
2916 		 * the proper address (see above with delta_disks):
2917 		 *
2918 		 * add disk(s)   -> begin
2919 		 * remove disk(s)-> end
2920 		 */
2921 		mddev->reshape_backwards = rs->dev[0].rdev.data_offset ? 0 : 1;
2922 	}
2923 
2924 	/*
2925 	 * Adjust device size for forward reshape
2926 	 * because md_finish_reshape() reduces it.
2927 	 */
2928 	if (!mddev->reshape_backwards)
2929 		rdev_for_each(rdev, &rs->md)
2930 			if (!test_bit(Journal, &rdev->flags))
2931 				rdev->sectors += reshape_sectors;
2932 
2933 	return r;
2934 }
2935 
2936 /*
2937  * If the md resync thread has updated superblock with max reshape position
2938  * at the end of a reshape but not (yet) reset the layout configuration
2939  * changes -> reset the latter.
2940  */
2941 static void rs_reset_inconclusive_reshape(struct raid_set *rs)
2942 {
2943 	if (!rs_is_reshaping(rs) && rs_is_layout_change(rs, true)) {
2944 		rs_set_cur(rs);
2945 		rs->md.delta_disks = 0;
2946 		rs->md.reshape_backwards = 0;
2947 	}
2948 }
2949 
2950 /*
2951  * Enable/disable discard support on RAID set depending on
2952  * RAID level and discard properties of underlying RAID members.
2953  */
2954 static void configure_discard_support(struct raid_set *rs)
2955 {
2956 	int i;
2957 	bool raid456;
2958 	struct dm_target *ti = rs->ti;
2959 
2960 	/*
2961 	 * XXX: RAID level 4,5,6 require zeroing for safety.
2962 	 */
2963 	raid456 = rs_is_raid456(rs);
2964 
2965 	for (i = 0; i < rs->raid_disks; i++) {
2966 		struct request_queue *q;
2967 
2968 		if (!rs->dev[i].rdev.bdev)
2969 			continue;
2970 
2971 		q = bdev_get_queue(rs->dev[i].rdev.bdev);
2972 		if (!q || !blk_queue_discard(q))
2973 			return;
2974 
2975 		if (raid456) {
2976 			if (!devices_handle_discard_safely) {
2977 				DMERR("raid456 discard support disabled due to discard_zeroes_data uncertainty.");
2978 				DMERR("Set dm-raid.devices_handle_discard_safely=Y to override.");
2979 				return;
2980 			}
2981 		}
2982 	}
2983 
2984 	ti->num_discard_bios = 1;
2985 }
2986 
2987 /*
2988  * Construct a RAID0/1/10/4/5/6 mapping:
2989  * Args:
2990  *	<raid_type> <#raid_params> <raid_params>{0,}	\
2991  *	<#raid_devs> [<meta_dev1> <dev1>]{1,}
2992  *
2993  * <raid_params> varies by <raid_type>.	 See 'parse_raid_params' for
2994  * details on possible <raid_params>.
2995  *
2996  * Userspace is free to initialize the metadata devices, hence the superblocks to
2997  * enforce recreation based on the passed in table parameters.
2998  *
2999  */
3000 static int raid_ctr(struct dm_target *ti, unsigned int argc, char **argv)
3001 {
3002 	int r;
3003 	bool resize = false;
3004 	struct raid_type *rt;
3005 	unsigned int num_raid_params, num_raid_devs;
3006 	sector_t sb_array_sectors, rdev_sectors, reshape_sectors;
3007 	struct raid_set *rs = NULL;
3008 	const char *arg;
3009 	struct rs_layout rs_layout;
3010 	struct dm_arg_set as = { argc, argv }, as_nrd;
3011 	struct dm_arg _args[] = {
3012 		{ 0, as.argc, "Cannot understand number of raid parameters" },
3013 		{ 1, 254, "Cannot understand number of raid devices parameters" }
3014 	};
3015 
3016 	arg = dm_shift_arg(&as);
3017 	if (!arg) {
3018 		ti->error = "No arguments";
3019 		return -EINVAL;
3020 	}
3021 
3022 	rt = get_raid_type(arg);
3023 	if (!rt) {
3024 		ti->error = "Unrecognised raid_type";
3025 		return -EINVAL;
3026 	}
3027 
3028 	/* Must have <#raid_params> */
3029 	if (dm_read_arg_group(_args, &as, &num_raid_params, &ti->error))
3030 		return -EINVAL;
3031 
3032 	/* number of raid device tupples <meta_dev data_dev> */
3033 	as_nrd = as;
3034 	dm_consume_args(&as_nrd, num_raid_params);
3035 	_args[1].max = (as_nrd.argc - 1) / 2;
3036 	if (dm_read_arg(_args + 1, &as_nrd, &num_raid_devs, &ti->error))
3037 		return -EINVAL;
3038 
3039 	if (!__within_range(num_raid_devs, 1, MAX_RAID_DEVICES)) {
3040 		ti->error = "Invalid number of supplied raid devices";
3041 		return -EINVAL;
3042 	}
3043 
3044 	rs = raid_set_alloc(ti, rt, num_raid_devs);
3045 	if (IS_ERR(rs))
3046 		return PTR_ERR(rs);
3047 
3048 	r = parse_raid_params(rs, &as, num_raid_params);
3049 	if (r)
3050 		goto bad;
3051 
3052 	r = parse_dev_params(rs, &as);
3053 	if (r)
3054 		goto bad;
3055 
3056 	rs->md.sync_super = super_sync;
3057 
3058 	/*
3059 	 * Calculate ctr requested array and device sizes to allow
3060 	 * for superblock analysis needing device sizes defined.
3061 	 *
3062 	 * Any existing superblock will overwrite the array and device sizes
3063 	 */
3064 	r = rs_set_dev_and_array_sectors(rs, rs->ti->len, false);
3065 	if (r)
3066 		goto bad;
3067 
3068 	/* Memorize just calculated, potentially larger sizes to grow the raid set in preresume */
3069 	rs->array_sectors = rs->md.array_sectors;
3070 	rs->dev_sectors = rs->md.dev_sectors;
3071 
3072 	/*
3073 	 * Backup any new raid set level, layout, ...
3074 	 * requested to be able to compare to superblock
3075 	 * members for conversion decisions.
3076 	 */
3077 	rs_config_backup(rs, &rs_layout);
3078 
3079 	r = analyse_superblocks(ti, rs);
3080 	if (r)
3081 		goto bad;
3082 
3083 	/* All in-core metadata now as of current superblocks after calling analyse_superblocks() */
3084 	sb_array_sectors = rs->md.array_sectors;
3085 	rdev_sectors = __rdev_sectors(rs);
3086 	if (!rdev_sectors) {
3087 		ti->error = "Invalid rdev size";
3088 		r = -EINVAL;
3089 		goto bad;
3090 	}
3091 
3092 
3093 	reshape_sectors = _get_reshape_sectors(rs);
3094 	if (rs->dev_sectors != rdev_sectors) {
3095 		resize = (rs->dev_sectors != rdev_sectors - reshape_sectors);
3096 		if (rs->dev_sectors > rdev_sectors - reshape_sectors)
3097 			set_bit(RT_FLAG_RS_GROW, &rs->runtime_flags);
3098 	}
3099 
3100 	INIT_WORK(&rs->md.event_work, do_table_event);
3101 	ti->private = rs;
3102 	ti->num_flush_bios = 1;
3103 
3104 	/* Restore any requested new layout for conversion decision */
3105 	rs_config_restore(rs, &rs_layout);
3106 
3107 	/*
3108 	 * Now that we have any superblock metadata available,
3109 	 * check for new, recovering, reshaping, to be taken over,
3110 	 * to be reshaped or an existing, unchanged raid set to
3111 	 * run in sequence.
3112 	 */
3113 	if (test_bit(MD_ARRAY_FIRST_USE, &rs->md.flags)) {
3114 		/* A new raid6 set has to be recovered to ensure proper parity and Q-Syndrome */
3115 		if (rs_is_raid6(rs) &&
3116 		    test_bit(__CTR_FLAG_NOSYNC, &rs->ctr_flags)) {
3117 			ti->error = "'nosync' not allowed for new raid6 set";
3118 			r = -EINVAL;
3119 			goto bad;
3120 		}
3121 		rs_setup_recovery(rs, 0);
3122 		set_bit(RT_FLAG_UPDATE_SBS, &rs->runtime_flags);
3123 		rs_set_new(rs);
3124 	} else if (rs_is_recovering(rs)) {
3125 		/* A recovering raid set may be resized */
3126 		goto size_check;
3127 	} else if (rs_is_reshaping(rs)) {
3128 		/* Have to reject size change request during reshape */
3129 		if (resize) {
3130 			ti->error = "Can't resize a reshaping raid set";
3131 			r = -EPERM;
3132 			goto bad;
3133 		}
3134 		/* skip setup rs */
3135 	} else if (rs_takeover_requested(rs)) {
3136 		if (rs_is_reshaping(rs)) {
3137 			ti->error = "Can't takeover a reshaping raid set";
3138 			r = -EPERM;
3139 			goto bad;
3140 		}
3141 
3142 		/* We can't takeover a journaled raid4/5/6 */
3143 		if (test_bit(__CTR_FLAG_JOURNAL_DEV, &rs->ctr_flags)) {
3144 			ti->error = "Can't takeover a journaled raid4/5/6 set";
3145 			r = -EPERM;
3146 			goto bad;
3147 		}
3148 
3149 		/*
3150 		 * If a takeover is needed, userspace sets any additional
3151 		 * devices to rebuild and we can check for a valid request here.
3152 		 *
3153 		 * If acceptible, set the level to the new requested
3154 		 * one, prohibit requesting recovery, allow the raid
3155 		 * set to run and store superblocks during resume.
3156 		 */
3157 		r = rs_check_takeover(rs);
3158 		if (r)
3159 			goto bad;
3160 
3161 		r = rs_setup_takeover(rs);
3162 		if (r)
3163 			goto bad;
3164 
3165 		set_bit(RT_FLAG_UPDATE_SBS, &rs->runtime_flags);
3166 		/* Takeover ain't recovery, so disable recovery */
3167 		rs_setup_recovery(rs, MaxSector);
3168 		rs_set_new(rs);
3169 	} else if (rs_reshape_requested(rs)) {
3170 		/* Only request grow on raid set size extensions, not on reshapes. */
3171 		clear_bit(RT_FLAG_RS_GROW, &rs->runtime_flags);
3172 
3173 		/*
3174 		 * No need to check for 'ongoing' takeover here, because takeover
3175 		 * is an instant operation as oposed to an ongoing reshape.
3176 		 */
3177 
3178 		/* We can't reshape a journaled raid4/5/6 */
3179 		if (test_bit(__CTR_FLAG_JOURNAL_DEV, &rs->ctr_flags)) {
3180 			ti->error = "Can't reshape a journaled raid4/5/6 set";
3181 			r = -EPERM;
3182 			goto bad;
3183 		}
3184 
3185 		/* Out-of-place space has to be available to allow for a reshape unless raid1! */
3186 		if (reshape_sectors || rs_is_raid1(rs)) {
3187 			/*
3188 			  * We can only prepare for a reshape here, because the
3189 			  * raid set needs to run to provide the repective reshape
3190 			  * check functions via its MD personality instance.
3191 			  *
3192 			  * So do the reshape check after md_run() succeeded.
3193 			  */
3194 			r = rs_prepare_reshape(rs);
3195 			if (r)
3196 				goto bad;
3197 
3198 			/* Reshaping ain't recovery, so disable recovery */
3199 			rs_setup_recovery(rs, MaxSector);
3200 		}
3201 		rs_set_cur(rs);
3202 	} else {
3203 size_check:
3204 		/* May not set recovery when a device rebuild is requested */
3205 		if (test_bit(__CTR_FLAG_REBUILD, &rs->ctr_flags)) {
3206 			clear_bit(RT_FLAG_RS_GROW, &rs->runtime_flags);
3207 			set_bit(RT_FLAG_UPDATE_SBS, &rs->runtime_flags);
3208 			rs_setup_recovery(rs, MaxSector);
3209 		} else if (test_bit(RT_FLAG_RS_GROW, &rs->runtime_flags)) {
3210 			/*
3211 			 * Set raid set to current size, i.e. size as of
3212 			 * superblocks to grow to larger size in preresume.
3213 			 */
3214 			r = rs_set_dev_and_array_sectors(rs, sb_array_sectors, false);
3215 			if (r)
3216 				goto bad;
3217 
3218 			rs_setup_recovery(rs, rs->md.recovery_cp < rs->md.dev_sectors ? rs->md.recovery_cp : rs->md.dev_sectors);
3219 		} else {
3220 			/* This is no size change or it is shrinking, update size and record in superblocks */
3221 			r = rs_set_dev_and_array_sectors(rs, rs->ti->len, false);
3222 			if (r)
3223 				goto bad;
3224 
3225 			if (sb_array_sectors > rs->array_sectors)
3226 				set_bit(RT_FLAG_UPDATE_SBS, &rs->runtime_flags);
3227 		}
3228 		rs_set_cur(rs);
3229 	}
3230 
3231 	/* If constructor requested it, change data and new_data offsets */
3232 	r = rs_adjust_data_offsets(rs);
3233 	if (r)
3234 		goto bad;
3235 
3236 	/* Catch any inconclusive reshape superblock content. */
3237 	rs_reset_inconclusive_reshape(rs);
3238 
3239 	/* Start raid set read-only and assumed clean to change in raid_resume() */
3240 	rs->md.ro = 1;
3241 	rs->md.in_sync = 1;
3242 
3243 	/* Keep array frozen until resume. */
3244 	set_bit(MD_RECOVERY_FROZEN, &rs->md.recovery);
3245 
3246 	/* Has to be held on running the array */
3247 	mddev_lock_nointr(&rs->md);
3248 	r = md_run(&rs->md);
3249 	rs->md.in_sync = 0; /* Assume already marked dirty */
3250 	if (r) {
3251 		ti->error = "Failed to run raid array";
3252 		mddev_unlock(&rs->md);
3253 		goto bad;
3254 	}
3255 
3256 	r = md_start(&rs->md);
3257 	if (r) {
3258 		ti->error = "Failed to start raid array";
3259 		mddev_unlock(&rs->md);
3260 		goto bad_md_start;
3261 	}
3262 
3263 	/* If raid4/5/6 journal mode explicitly requested (only possible with journal dev) -> set it */
3264 	if (test_bit(__CTR_FLAG_JOURNAL_MODE, &rs->ctr_flags)) {
3265 		r = r5c_journal_mode_set(&rs->md, rs->journal_dev.mode);
3266 		if (r) {
3267 			ti->error = "Failed to set raid4/5/6 journal mode";
3268 			mddev_unlock(&rs->md);
3269 			goto bad_journal_mode_set;
3270 		}
3271 	}
3272 
3273 	mddev_suspend(&rs->md);
3274 	set_bit(RT_FLAG_RS_SUSPENDED, &rs->runtime_flags);
3275 
3276 	/* Try to adjust the raid4/5/6 stripe cache size to the stripe size */
3277 	if (rs_is_raid456(rs)) {
3278 		r = rs_set_raid456_stripe_cache(rs);
3279 		if (r)
3280 			goto bad_stripe_cache;
3281 	}
3282 
3283 	/* Now do an early reshape check */
3284 	if (test_bit(RT_FLAG_RESHAPE_RS, &rs->runtime_flags)) {
3285 		r = rs_check_reshape(rs);
3286 		if (r)
3287 			goto bad_check_reshape;
3288 
3289 		/* Restore new, ctr requested layout to perform check */
3290 		rs_config_restore(rs, &rs_layout);
3291 
3292 		if (rs->md.pers->start_reshape) {
3293 			r = rs->md.pers->check_reshape(&rs->md);
3294 			if (r) {
3295 				ti->error = "Reshape check failed";
3296 				goto bad_check_reshape;
3297 			}
3298 		}
3299 	}
3300 
3301 	/* Disable/enable discard support on raid set. */
3302 	configure_discard_support(rs);
3303 
3304 	mddev_unlock(&rs->md);
3305 	return 0;
3306 
3307 bad_md_start:
3308 bad_journal_mode_set:
3309 bad_stripe_cache:
3310 bad_check_reshape:
3311 	md_stop(&rs->md);
3312 bad:
3313 	raid_set_free(rs);
3314 
3315 	return r;
3316 }
3317 
3318 static void raid_dtr(struct dm_target *ti)
3319 {
3320 	struct raid_set *rs = ti->private;
3321 
3322 	md_stop(&rs->md);
3323 	raid_set_free(rs);
3324 }
3325 
3326 static int raid_map(struct dm_target *ti, struct bio *bio)
3327 {
3328 	struct raid_set *rs = ti->private;
3329 	struct mddev *mddev = &rs->md;
3330 
3331 	/*
3332 	 * If we're reshaping to add disk(s)), ti->len and
3333 	 * mddev->array_sectors will differ during the process
3334 	 * (ti->len > mddev->array_sectors), so we have to requeue
3335 	 * bios with addresses > mddev->array_sectors here or
3336 	 * there will occur accesses past EOD of the component
3337 	 * data images thus erroring the raid set.
3338 	 */
3339 	if (unlikely(bio_end_sector(bio) > mddev->array_sectors))
3340 		return DM_MAPIO_REQUEUE;
3341 
3342 	md_handle_request(mddev, bio);
3343 
3344 	return DM_MAPIO_SUBMITTED;
3345 }
3346 
3347 /* Return sync state string for @state */
3348 enum sync_state { st_frozen, st_reshape, st_resync, st_check, st_repair, st_recover, st_idle };
3349 static const char *sync_str(enum sync_state state)
3350 {
3351 	/* Has to be in above sync_state order! */
3352 	static const char *sync_strs[] = {
3353 		"frozen",
3354 		"reshape",
3355 		"resync",
3356 		"check",
3357 		"repair",
3358 		"recover",
3359 		"idle"
3360 	};
3361 
3362 	return __within_range(state, 0, ARRAY_SIZE(sync_strs) - 1) ? sync_strs[state] : "undef";
3363 };
3364 
3365 /* Return enum sync_state for @mddev derived from @recovery flags */
3366 static enum sync_state decipher_sync_action(struct mddev *mddev, unsigned long recovery)
3367 {
3368 	if (test_bit(MD_RECOVERY_FROZEN, &recovery))
3369 		return st_frozen;
3370 
3371 	/* The MD sync thread can be done with io or be interrupted but still be running */
3372 	if (!test_bit(MD_RECOVERY_DONE, &recovery) &&
3373 	    (test_bit(MD_RECOVERY_RUNNING, &recovery) ||
3374 	     (!mddev->ro && test_bit(MD_RECOVERY_NEEDED, &recovery)))) {
3375 		if (test_bit(MD_RECOVERY_RESHAPE, &recovery))
3376 			return st_reshape;
3377 
3378 		if (test_bit(MD_RECOVERY_SYNC, &recovery)) {
3379 			if (!test_bit(MD_RECOVERY_REQUESTED, &recovery))
3380 				return st_resync;
3381 			if (test_bit(MD_RECOVERY_CHECK, &recovery))
3382 				return st_check;
3383 			return st_repair;
3384 		}
3385 
3386 		if (test_bit(MD_RECOVERY_RECOVER, &recovery))
3387 			return st_recover;
3388 
3389 		if (mddev->reshape_position != MaxSector)
3390 			return st_reshape;
3391 	}
3392 
3393 	return st_idle;
3394 }
3395 
3396 /*
3397  * Return status string for @rdev
3398  *
3399  * Status characters:
3400  *
3401  *  'D' = Dead/Failed raid set component or raid4/5/6 journal device
3402  *  'a' = Alive but not in-sync raid set component _or_ alive raid4/5/6 'write_back' journal device
3403  *  'A' = Alive and in-sync raid set component _or_ alive raid4/5/6 'write_through' journal device
3404  *  '-' = Non-existing device (i.e. uspace passed '- -' into the ctr)
3405  */
3406 static const char *__raid_dev_status(struct raid_set *rs, struct md_rdev *rdev)
3407 {
3408 	if (!rdev->bdev)
3409 		return "-";
3410 	else if (test_bit(Faulty, &rdev->flags))
3411 		return "D";
3412 	else if (test_bit(Journal, &rdev->flags))
3413 		return (rs->journal_dev.mode == R5C_JOURNAL_MODE_WRITE_THROUGH) ? "A" : "a";
3414 	else if (test_bit(RT_FLAG_RS_RESYNCING, &rs->runtime_flags) ||
3415 		 (!test_bit(RT_FLAG_RS_IN_SYNC, &rs->runtime_flags) &&
3416 		  !test_bit(In_sync, &rdev->flags)))
3417 		return "a";
3418 	else
3419 		return "A";
3420 }
3421 
3422 /* Helper to return resync/reshape progress for @rs and runtime flags for raid set in sync / resynching */
3423 static sector_t rs_get_progress(struct raid_set *rs, unsigned long recovery,
3424 				enum sync_state state, sector_t resync_max_sectors)
3425 {
3426 	sector_t r;
3427 	struct mddev *mddev = &rs->md;
3428 
3429 	clear_bit(RT_FLAG_RS_IN_SYNC, &rs->runtime_flags);
3430 	clear_bit(RT_FLAG_RS_RESYNCING, &rs->runtime_flags);
3431 
3432 	if (rs_is_raid0(rs)) {
3433 		r = resync_max_sectors;
3434 		set_bit(RT_FLAG_RS_IN_SYNC, &rs->runtime_flags);
3435 
3436 	} else {
3437 		if (state == st_idle && !test_bit(MD_RECOVERY_INTR, &recovery))
3438 			r = mddev->recovery_cp;
3439 		else
3440 			r = mddev->curr_resync_completed;
3441 
3442 		if (state == st_idle && r >= resync_max_sectors) {
3443 			/*
3444 			 * Sync complete.
3445 			 */
3446 			/* In case we have finished recovering, the array is in sync. */
3447 			if (test_bit(MD_RECOVERY_RECOVER, &recovery))
3448 				set_bit(RT_FLAG_RS_IN_SYNC, &rs->runtime_flags);
3449 
3450 		} else if (state == st_recover)
3451 			/*
3452 			 * In case we are recovering, the array is not in sync
3453 			 * and health chars should show the recovering legs.
3454 			 *
3455 			 * Already retrieved recovery offset from curr_resync_completed above.
3456 			 */
3457 			;
3458 
3459 		else if (state == st_resync || state == st_reshape)
3460 			/*
3461 			 * If "resync/reshape" is occurring, the raid set
3462 			 * is or may be out of sync hence the health
3463 			 * characters shall be 'a'.
3464 			 */
3465 			set_bit(RT_FLAG_RS_RESYNCING, &rs->runtime_flags);
3466 
3467 		else if (state == st_check || state == st_repair)
3468 			/*
3469 			 * If "check" or "repair" is occurring, the raid set has
3470 			 * undergone an initial sync and the health characters
3471 			 * should not be 'a' anymore.
3472 			 */
3473 			set_bit(RT_FLAG_RS_IN_SYNC, &rs->runtime_flags);
3474 
3475 		else if (test_bit(MD_RECOVERY_NEEDED, &recovery))
3476 			/*
3477 			 * We are idle and recovery is needed, prevent 'A' chars race
3478 			 * caused by components still set to in-sync by constructor.
3479 			 */
3480 			set_bit(RT_FLAG_RS_RESYNCING, &rs->runtime_flags);
3481 
3482 		else {
3483 			/*
3484 			 * We are idle and the raid set may be doing an initial
3485 			 * sync, or it may be rebuilding individual components.
3486 			 * If all the devices are In_sync, then it is the raid set
3487 			 * that is being initialized.
3488 			 */
3489 			struct md_rdev *rdev;
3490 
3491 			set_bit(RT_FLAG_RS_IN_SYNC, &rs->runtime_flags);
3492 			rdev_for_each(rdev, mddev)
3493 				if (!test_bit(Journal, &rdev->flags) &&
3494 				    !test_bit(In_sync, &rdev->flags)) {
3495 					clear_bit(RT_FLAG_RS_IN_SYNC, &rs->runtime_flags);
3496 					break;
3497 				}
3498 		}
3499 	}
3500 
3501 	return min(r, resync_max_sectors);
3502 }
3503 
3504 /* Helper to return @dev name or "-" if !@dev */
3505 static const char *__get_dev_name(struct dm_dev *dev)
3506 {
3507 	return dev ? dev->name : "-";
3508 }
3509 
3510 static void raid_status(struct dm_target *ti, status_type_t type,
3511 			unsigned int status_flags, char *result, unsigned int maxlen)
3512 {
3513 	struct raid_set *rs = ti->private;
3514 	struct mddev *mddev = &rs->md;
3515 	struct r5conf *conf = mddev->private;
3516 	int i, max_nr_stripes = conf ? conf->max_nr_stripes : 0;
3517 	unsigned long recovery;
3518 	unsigned int raid_param_cnt = 1; /* at least 1 for chunksize */
3519 	unsigned int sz = 0;
3520 	unsigned int rebuild_writemostly_count = 0;
3521 	sector_t progress, resync_max_sectors, resync_mismatches;
3522 	enum sync_state state;
3523 	struct raid_type *rt;
3524 
3525 	switch (type) {
3526 	case STATUSTYPE_INFO:
3527 		/* *Should* always succeed */
3528 		rt = get_raid_type_by_ll(mddev->new_level, mddev->new_layout);
3529 		if (!rt)
3530 			return;
3531 
3532 		DMEMIT("%s %d ", rt->name, mddev->raid_disks);
3533 
3534 		/* Access most recent mddev properties for status output */
3535 		smp_rmb();
3536 		/* Get sensible max sectors even if raid set not yet started */
3537 		resync_max_sectors = test_bit(RT_FLAG_RS_PRERESUMED, &rs->runtime_flags) ?
3538 				      mddev->resync_max_sectors : mddev->dev_sectors;
3539 		recovery = rs->md.recovery;
3540 		state = decipher_sync_action(mddev, recovery);
3541 		progress = rs_get_progress(rs, recovery, state, resync_max_sectors);
3542 		resync_mismatches = (mddev->last_sync_action && !strcasecmp(mddev->last_sync_action, "check")) ?
3543 				    atomic64_read(&mddev->resync_mismatches) : 0;
3544 
3545 		/* HM FIXME: do we want another state char for raid0? It shows 'D'/'A'/'-' now */
3546 		for (i = 0; i < rs->raid_disks; i++)
3547 			DMEMIT(__raid_dev_status(rs, &rs->dev[i].rdev));
3548 
3549 		/*
3550 		 * In-sync/Reshape ratio:
3551 		 *  The in-sync ratio shows the progress of:
3552 		 *   - Initializing the raid set
3553 		 *   - Rebuilding a subset of devices of the raid set
3554 		 *  The user can distinguish between the two by referring
3555 		 *  to the status characters.
3556 		 *
3557 		 *  The reshape ratio shows the progress of
3558 		 *  changing the raid layout or the number of
3559 		 *  disks of a raid set
3560 		 */
3561 		DMEMIT(" %llu/%llu", (unsigned long long) progress,
3562 				     (unsigned long long) resync_max_sectors);
3563 
3564 		/*
3565 		 * v1.5.0+:
3566 		 *
3567 		 * Sync action:
3568 		 *   See Documentation/admin-guide/device-mapper/dm-raid.rst for
3569 		 *   information on each of these states.
3570 		 */
3571 		DMEMIT(" %s", sync_str(state));
3572 
3573 		/*
3574 		 * v1.5.0+:
3575 		 *
3576 		 * resync_mismatches/mismatch_cnt
3577 		 *   This field shows the number of discrepancies found when
3578 		 *   performing a "check" of the raid set.
3579 		 */
3580 		DMEMIT(" %llu", (unsigned long long) resync_mismatches);
3581 
3582 		/*
3583 		 * v1.9.0+:
3584 		 *
3585 		 * data_offset (needed for out of space reshaping)
3586 		 *   This field shows the data offset into the data
3587 		 *   image LV where the first stripes data starts.
3588 		 *
3589 		 * We keep data_offset equal on all raid disks of the set,
3590 		 * so retrieving it from the first raid disk is sufficient.
3591 		 */
3592 		DMEMIT(" %llu", (unsigned long long) rs->dev[0].rdev.data_offset);
3593 
3594 		/*
3595 		 * v1.10.0+:
3596 		 */
3597 		DMEMIT(" %s", test_bit(__CTR_FLAG_JOURNAL_DEV, &rs->ctr_flags) ?
3598 			      __raid_dev_status(rs, &rs->journal_dev.rdev) : "-");
3599 		break;
3600 
3601 	case STATUSTYPE_TABLE:
3602 		/* Report the table line string you would use to construct this raid set */
3603 
3604 		/*
3605 		 * Count any rebuild or writemostly argument pairs and subtract the
3606 		 * hweight count being added below of any rebuild and writemostly ctr flags.
3607 		 */
3608 		for (i = 0; i < rs->raid_disks; i++) {
3609 			rebuild_writemostly_count += (test_bit(i, (void *) rs->rebuild_disks) ? 2 : 0) +
3610 						     (test_bit(WriteMostly, &rs->dev[i].rdev.flags) ? 2 : 0);
3611 		}
3612 		rebuild_writemostly_count -= (test_bit(__CTR_FLAG_REBUILD, &rs->ctr_flags) ? 2 : 0) +
3613 					     (test_bit(__CTR_FLAG_WRITE_MOSTLY, &rs->ctr_flags) ? 2 : 0);
3614 		/* Calculate raid parameter count based on ^ rebuild/writemostly argument counts and ctr flags set. */
3615 		raid_param_cnt += rebuild_writemostly_count +
3616 				  hweight32(rs->ctr_flags & CTR_FLAG_OPTIONS_NO_ARGS) +
3617 				  hweight32(rs->ctr_flags & CTR_FLAG_OPTIONS_ONE_ARG) * 2;
3618 		/* Emit table line */
3619 		/* This has to be in the documented order for userspace! */
3620 		DMEMIT("%s %u %u", rs->raid_type->name, raid_param_cnt, mddev->new_chunk_sectors);
3621 		if (test_bit(__CTR_FLAG_SYNC, &rs->ctr_flags))
3622 			DMEMIT(" %s", dm_raid_arg_name_by_flag(CTR_FLAG_SYNC));
3623 		if (test_bit(__CTR_FLAG_NOSYNC, &rs->ctr_flags))
3624 			DMEMIT(" %s", dm_raid_arg_name_by_flag(CTR_FLAG_NOSYNC));
3625 		if (test_bit(__CTR_FLAG_REBUILD, &rs->ctr_flags))
3626 			for (i = 0; i < rs->raid_disks; i++)
3627 				if (test_bit(i, (void *) rs->rebuild_disks))
3628 					DMEMIT(" %s %u", dm_raid_arg_name_by_flag(CTR_FLAG_REBUILD), i);
3629 		if (test_bit(__CTR_FLAG_DAEMON_SLEEP, &rs->ctr_flags))
3630 			DMEMIT(" %s %lu", dm_raid_arg_name_by_flag(CTR_FLAG_DAEMON_SLEEP),
3631 					  mddev->bitmap_info.daemon_sleep);
3632 		if (test_bit(__CTR_FLAG_MIN_RECOVERY_RATE, &rs->ctr_flags))
3633 			DMEMIT(" %s %d", dm_raid_arg_name_by_flag(CTR_FLAG_MIN_RECOVERY_RATE),
3634 					 mddev->sync_speed_min);
3635 		if (test_bit(__CTR_FLAG_MAX_RECOVERY_RATE, &rs->ctr_flags))
3636 			DMEMIT(" %s %d", dm_raid_arg_name_by_flag(CTR_FLAG_MAX_RECOVERY_RATE),
3637 					 mddev->sync_speed_max);
3638 		if (test_bit(__CTR_FLAG_WRITE_MOSTLY, &rs->ctr_flags))
3639 			for (i = 0; i < rs->raid_disks; i++)
3640 				if (test_bit(WriteMostly, &rs->dev[i].rdev.flags))
3641 					DMEMIT(" %s %d", dm_raid_arg_name_by_flag(CTR_FLAG_WRITE_MOSTLY),
3642 					       rs->dev[i].rdev.raid_disk);
3643 		if (test_bit(__CTR_FLAG_MAX_WRITE_BEHIND, &rs->ctr_flags))
3644 			DMEMIT(" %s %lu", dm_raid_arg_name_by_flag(CTR_FLAG_MAX_WRITE_BEHIND),
3645 					  mddev->bitmap_info.max_write_behind);
3646 		if (test_bit(__CTR_FLAG_STRIPE_CACHE, &rs->ctr_flags))
3647 			DMEMIT(" %s %d", dm_raid_arg_name_by_flag(CTR_FLAG_STRIPE_CACHE),
3648 					 max_nr_stripes);
3649 		if (test_bit(__CTR_FLAG_REGION_SIZE, &rs->ctr_flags))
3650 			DMEMIT(" %s %llu", dm_raid_arg_name_by_flag(CTR_FLAG_REGION_SIZE),
3651 					   (unsigned long long) to_sector(mddev->bitmap_info.chunksize));
3652 		if (test_bit(__CTR_FLAG_RAID10_COPIES, &rs->ctr_flags))
3653 			DMEMIT(" %s %d", dm_raid_arg_name_by_flag(CTR_FLAG_RAID10_COPIES),
3654 					 raid10_md_layout_to_copies(mddev->layout));
3655 		if (test_bit(__CTR_FLAG_RAID10_FORMAT, &rs->ctr_flags))
3656 			DMEMIT(" %s %s", dm_raid_arg_name_by_flag(CTR_FLAG_RAID10_FORMAT),
3657 					 raid10_md_layout_to_format(mddev->layout));
3658 		if (test_bit(__CTR_FLAG_DELTA_DISKS, &rs->ctr_flags))
3659 			DMEMIT(" %s %d", dm_raid_arg_name_by_flag(CTR_FLAG_DELTA_DISKS),
3660 					 max(rs->delta_disks, mddev->delta_disks));
3661 		if (test_bit(__CTR_FLAG_DATA_OFFSET, &rs->ctr_flags))
3662 			DMEMIT(" %s %llu", dm_raid_arg_name_by_flag(CTR_FLAG_DATA_OFFSET),
3663 					   (unsigned long long) rs->data_offset);
3664 		if (test_bit(__CTR_FLAG_JOURNAL_DEV, &rs->ctr_flags))
3665 			DMEMIT(" %s %s", dm_raid_arg_name_by_flag(CTR_FLAG_JOURNAL_DEV),
3666 					__get_dev_name(rs->journal_dev.dev));
3667 		if (test_bit(__CTR_FLAG_JOURNAL_MODE, &rs->ctr_flags))
3668 			DMEMIT(" %s %s", dm_raid_arg_name_by_flag(CTR_FLAG_JOURNAL_MODE),
3669 					 md_journal_mode_to_dm_raid(rs->journal_dev.mode));
3670 		DMEMIT(" %d", rs->raid_disks);
3671 		for (i = 0; i < rs->raid_disks; i++)
3672 			DMEMIT(" %s %s", __get_dev_name(rs->dev[i].meta_dev),
3673 					 __get_dev_name(rs->dev[i].data_dev));
3674 	}
3675 }
3676 
3677 static int raid_message(struct dm_target *ti, unsigned int argc, char **argv,
3678 			char *result, unsigned maxlen)
3679 {
3680 	struct raid_set *rs = ti->private;
3681 	struct mddev *mddev = &rs->md;
3682 
3683 	if (!mddev->pers || !mddev->pers->sync_request)
3684 		return -EINVAL;
3685 
3686 	if (!strcasecmp(argv[0], "frozen"))
3687 		set_bit(MD_RECOVERY_FROZEN, &mddev->recovery);
3688 	else
3689 		clear_bit(MD_RECOVERY_FROZEN, &mddev->recovery);
3690 
3691 	if (!strcasecmp(argv[0], "idle") || !strcasecmp(argv[0], "frozen")) {
3692 		if (mddev->sync_thread) {
3693 			set_bit(MD_RECOVERY_INTR, &mddev->recovery);
3694 			md_reap_sync_thread(mddev);
3695 		}
3696 	} else if (decipher_sync_action(mddev, mddev->recovery) != st_idle)
3697 		return -EBUSY;
3698 	else if (!strcasecmp(argv[0], "resync"))
3699 		; /* MD_RECOVERY_NEEDED set below */
3700 	else if (!strcasecmp(argv[0], "recover"))
3701 		set_bit(MD_RECOVERY_RECOVER, &mddev->recovery);
3702 	else {
3703 		if (!strcasecmp(argv[0], "check")) {
3704 			set_bit(MD_RECOVERY_CHECK, &mddev->recovery);
3705 			set_bit(MD_RECOVERY_REQUESTED, &mddev->recovery);
3706 			set_bit(MD_RECOVERY_SYNC, &mddev->recovery);
3707 		} else if (!strcasecmp(argv[0], "repair")) {
3708 			set_bit(MD_RECOVERY_REQUESTED, &mddev->recovery);
3709 			set_bit(MD_RECOVERY_SYNC, &mddev->recovery);
3710 		} else
3711 			return -EINVAL;
3712 	}
3713 	if (mddev->ro == 2) {
3714 		/* A write to sync_action is enough to justify
3715 		 * canceling read-auto mode
3716 		 */
3717 		mddev->ro = 0;
3718 		if (!mddev->suspended && mddev->sync_thread)
3719 			md_wakeup_thread(mddev->sync_thread);
3720 	}
3721 	set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
3722 	if (!mddev->suspended && mddev->thread)
3723 		md_wakeup_thread(mddev->thread);
3724 
3725 	return 0;
3726 }
3727 
3728 static int raid_iterate_devices(struct dm_target *ti,
3729 				iterate_devices_callout_fn fn, void *data)
3730 {
3731 	struct raid_set *rs = ti->private;
3732 	unsigned int i;
3733 	int r = 0;
3734 
3735 	for (i = 0; !r && i < rs->md.raid_disks; i++)
3736 		if (rs->dev[i].data_dev)
3737 			r = fn(ti,
3738 				 rs->dev[i].data_dev,
3739 				 0, /* No offset on data devs */
3740 				 rs->md.dev_sectors,
3741 				 data);
3742 
3743 	return r;
3744 }
3745 
3746 static void raid_io_hints(struct dm_target *ti, struct queue_limits *limits)
3747 {
3748 	struct raid_set *rs = ti->private;
3749 	unsigned int chunk_size_bytes = to_bytes(rs->md.chunk_sectors);
3750 
3751 	blk_limits_io_min(limits, chunk_size_bytes);
3752 	blk_limits_io_opt(limits, chunk_size_bytes * mddev_data_stripes(rs));
3753 }
3754 
3755 static void raid_postsuspend(struct dm_target *ti)
3756 {
3757 	struct raid_set *rs = ti->private;
3758 
3759 	if (!test_and_set_bit(RT_FLAG_RS_SUSPENDED, &rs->runtime_flags)) {
3760 		/* Writes have to be stopped before suspending to avoid deadlocks. */
3761 		if (!test_bit(MD_RECOVERY_FROZEN, &rs->md.recovery))
3762 			md_stop_writes(&rs->md);
3763 
3764 		mddev_lock_nointr(&rs->md);
3765 		mddev_suspend(&rs->md);
3766 		mddev_unlock(&rs->md);
3767 	}
3768 }
3769 
3770 static void attempt_restore_of_faulty_devices(struct raid_set *rs)
3771 {
3772 	int i;
3773 	uint64_t cleared_failed_devices[DISKS_ARRAY_ELEMS];
3774 	unsigned long flags;
3775 	bool cleared = false;
3776 	struct dm_raid_superblock *sb;
3777 	struct mddev *mddev = &rs->md;
3778 	struct md_rdev *r;
3779 
3780 	/* RAID personalities have to provide hot add/remove methods or we need to bail out. */
3781 	if (!mddev->pers || !mddev->pers->hot_add_disk || !mddev->pers->hot_remove_disk)
3782 		return;
3783 
3784 	memset(cleared_failed_devices, 0, sizeof(cleared_failed_devices));
3785 
3786 	for (i = 0; i < mddev->raid_disks; i++) {
3787 		r = &rs->dev[i].rdev;
3788 		/* HM FIXME: enhance journal device recovery processing */
3789 		if (test_bit(Journal, &r->flags))
3790 			continue;
3791 
3792 		if (test_bit(Faulty, &r->flags) &&
3793 		    r->meta_bdev && !read_disk_sb(r, r->sb_size, true)) {
3794 			DMINFO("Faulty %s device #%d has readable super block."
3795 			       "  Attempting to revive it.",
3796 			       rs->raid_type->name, i);
3797 
3798 			/*
3799 			 * Faulty bit may be set, but sometimes the array can
3800 			 * be suspended before the personalities can respond
3801 			 * by removing the device from the array (i.e. calling
3802 			 * 'hot_remove_disk').	If they haven't yet removed
3803 			 * the failed device, its 'raid_disk' number will be
3804 			 * '>= 0' - meaning we must call this function
3805 			 * ourselves.
3806 			 */
3807 			flags = r->flags;
3808 			clear_bit(In_sync, &r->flags); /* Mandatory for hot remove. */
3809 			if (r->raid_disk >= 0) {
3810 				if (mddev->pers->hot_remove_disk(mddev, r)) {
3811 					/* Failed to revive this device, try next */
3812 					r->flags = flags;
3813 					continue;
3814 				}
3815 			} else
3816 				r->raid_disk = r->saved_raid_disk = i;
3817 
3818 			clear_bit(Faulty, &r->flags);
3819 			clear_bit(WriteErrorSeen, &r->flags);
3820 
3821 			if (mddev->pers->hot_add_disk(mddev, r)) {
3822 				/* Failed to revive this device, try next */
3823 				r->raid_disk = r->saved_raid_disk = -1;
3824 				r->flags = flags;
3825 			} else {
3826 				clear_bit(In_sync, &r->flags);
3827 				r->recovery_offset = 0;
3828 				set_bit(i, (void *) cleared_failed_devices);
3829 				cleared = true;
3830 			}
3831 		}
3832 	}
3833 
3834 	/* If any failed devices could be cleared, update all sbs failed_devices bits */
3835 	if (cleared) {
3836 		uint64_t failed_devices[DISKS_ARRAY_ELEMS];
3837 
3838 		rdev_for_each(r, &rs->md) {
3839 			if (test_bit(Journal, &r->flags))
3840 				continue;
3841 
3842 			sb = page_address(r->sb_page);
3843 			sb_retrieve_failed_devices(sb, failed_devices);
3844 
3845 			for (i = 0; i < DISKS_ARRAY_ELEMS; i++)
3846 				failed_devices[i] &= ~cleared_failed_devices[i];
3847 
3848 			sb_update_failed_devices(sb, failed_devices);
3849 		}
3850 	}
3851 }
3852 
3853 static int __load_dirty_region_bitmap(struct raid_set *rs)
3854 {
3855 	int r = 0;
3856 
3857 	/* Try loading the bitmap unless "raid0", which does not have one */
3858 	if (!rs_is_raid0(rs) &&
3859 	    !test_and_set_bit(RT_FLAG_RS_BITMAP_LOADED, &rs->runtime_flags)) {
3860 		r = md_bitmap_load(&rs->md);
3861 		if (r)
3862 			DMERR("Failed to load bitmap");
3863 	}
3864 
3865 	return r;
3866 }
3867 
3868 /* Enforce updating all superblocks */
3869 static void rs_update_sbs(struct raid_set *rs)
3870 {
3871 	struct mddev *mddev = &rs->md;
3872 	int ro = mddev->ro;
3873 
3874 	set_bit(MD_SB_CHANGE_DEVS, &mddev->sb_flags);
3875 	mddev->ro = 0;
3876 	md_update_sb(mddev, 1);
3877 	mddev->ro = ro;
3878 }
3879 
3880 /*
3881  * Reshape changes raid algorithm of @rs to new one within personality
3882  * (e.g. raid6_zr -> raid6_nc), changes stripe size, adds/removes
3883  * disks from a raid set thus growing/shrinking it or resizes the set
3884  *
3885  * Call mddev_lock_nointr() before!
3886  */
3887 static int rs_start_reshape(struct raid_set *rs)
3888 {
3889 	int r;
3890 	struct mddev *mddev = &rs->md;
3891 	struct md_personality *pers = mddev->pers;
3892 
3893 	/* Don't allow the sync thread to work until the table gets reloaded. */
3894 	set_bit(MD_RECOVERY_WAIT, &mddev->recovery);
3895 
3896 	r = rs_setup_reshape(rs);
3897 	if (r)
3898 		return r;
3899 
3900 	/*
3901 	 * Check any reshape constraints enforced by the personalility
3902 	 *
3903 	 * May as well already kick the reshape off so that * pers->start_reshape() becomes optional.
3904 	 */
3905 	r = pers->check_reshape(mddev);
3906 	if (r) {
3907 		rs->ti->error = "pers->check_reshape() failed";
3908 		return r;
3909 	}
3910 
3911 	/*
3912 	 * Personality may not provide start reshape method in which
3913 	 * case check_reshape above has already covered everything
3914 	 */
3915 	if (pers->start_reshape) {
3916 		r = pers->start_reshape(mddev);
3917 		if (r) {
3918 			rs->ti->error = "pers->start_reshape() failed";
3919 			return r;
3920 		}
3921 	}
3922 
3923 	/*
3924 	 * Now reshape got set up, update superblocks to
3925 	 * reflect the fact so that a table reload will
3926 	 * access proper superblock content in the ctr.
3927 	 */
3928 	rs_update_sbs(rs);
3929 
3930 	return 0;
3931 }
3932 
3933 static int raid_preresume(struct dm_target *ti)
3934 {
3935 	int r;
3936 	struct raid_set *rs = ti->private;
3937 	struct mddev *mddev = &rs->md;
3938 
3939 	/* This is a resume after a suspend of the set -> it's already started. */
3940 	if (test_and_set_bit(RT_FLAG_RS_PRERESUMED, &rs->runtime_flags))
3941 		return 0;
3942 
3943 	/*
3944 	 * The superblocks need to be updated on disk if the
3945 	 * array is new or new devices got added (thus zeroed
3946 	 * out by userspace) or __load_dirty_region_bitmap
3947 	 * will overwrite them in core with old data or fail.
3948 	 */
3949 	if (test_bit(RT_FLAG_UPDATE_SBS, &rs->runtime_flags))
3950 		rs_update_sbs(rs);
3951 
3952 	/* Load the bitmap from disk unless raid0 */
3953 	r = __load_dirty_region_bitmap(rs);
3954 	if (r)
3955 		return r;
3956 
3957 	/* We are extending the raid set size, adjust mddev/md_rdev sizes and set capacity. */
3958 	if (test_bit(RT_FLAG_RS_GROW, &rs->runtime_flags)) {
3959 		mddev->array_sectors = rs->array_sectors;
3960 		mddev->dev_sectors = rs->dev_sectors;
3961 		rs_set_rdev_sectors(rs);
3962 		rs_set_capacity(rs);
3963 	}
3964 
3965 	/* Resize bitmap to adjust to changed region size (aka MD bitmap chunksize) or grown device size */
3966         if (test_bit(RT_FLAG_RS_BITMAP_LOADED, &rs->runtime_flags) && mddev->bitmap &&
3967 	    (test_bit(RT_FLAG_RS_GROW, &rs->runtime_flags) ||
3968 	     (rs->requested_bitmap_chunk_sectors &&
3969 	       mddev->bitmap_info.chunksize != to_bytes(rs->requested_bitmap_chunk_sectors)))) {
3970 		int chunksize = to_bytes(rs->requested_bitmap_chunk_sectors) ?: mddev->bitmap_info.chunksize;
3971 
3972 		r = md_bitmap_resize(mddev->bitmap, mddev->dev_sectors, chunksize, 0);
3973 		if (r)
3974 			DMERR("Failed to resize bitmap");
3975 	}
3976 
3977 	/* Check for any resize/reshape on @rs and adjust/initiate */
3978 	/* Be prepared for mddev_resume() in raid_resume() */
3979 	set_bit(MD_RECOVERY_FROZEN, &mddev->recovery);
3980 	if (mddev->recovery_cp && mddev->recovery_cp < MaxSector) {
3981 		set_bit(MD_RECOVERY_REQUESTED, &mddev->recovery);
3982 		mddev->resync_min = mddev->recovery_cp;
3983 		if (test_bit(RT_FLAG_RS_GROW, &rs->runtime_flags))
3984 			mddev->resync_max_sectors = mddev->dev_sectors;
3985 	}
3986 
3987 	/* Check for any reshape request unless new raid set */
3988 	if (test_bit(RT_FLAG_RESHAPE_RS, &rs->runtime_flags)) {
3989 		/* Initiate a reshape. */
3990 		rs_set_rdev_sectors(rs);
3991 		mddev_lock_nointr(mddev);
3992 		r = rs_start_reshape(rs);
3993 		mddev_unlock(mddev);
3994 		if (r)
3995 			DMWARN("Failed to check/start reshape, continuing without change");
3996 		r = 0;
3997 	}
3998 
3999 	return r;
4000 }
4001 
4002 static void raid_resume(struct dm_target *ti)
4003 {
4004 	struct raid_set *rs = ti->private;
4005 	struct mddev *mddev = &rs->md;
4006 
4007 	if (test_and_set_bit(RT_FLAG_RS_RESUMED, &rs->runtime_flags)) {
4008 		/*
4009 		 * A secondary resume while the device is active.
4010 		 * Take this opportunity to check whether any failed
4011 		 * devices are reachable again.
4012 		 */
4013 		attempt_restore_of_faulty_devices(rs);
4014 	}
4015 
4016 	if (test_and_clear_bit(RT_FLAG_RS_SUSPENDED, &rs->runtime_flags)) {
4017 		/* Only reduce raid set size before running a disk removing reshape. */
4018 		if (mddev->delta_disks < 0)
4019 			rs_set_capacity(rs);
4020 
4021 		mddev_lock_nointr(mddev);
4022 		clear_bit(MD_RECOVERY_FROZEN, &mddev->recovery);
4023 		mddev->ro = 0;
4024 		mddev->in_sync = 0;
4025 		mddev_resume(mddev);
4026 		mddev_unlock(mddev);
4027 	}
4028 }
4029 
4030 static struct target_type raid_target = {
4031 	.name = "raid",
4032 	.version = {1, 15, 1},
4033 	.module = THIS_MODULE,
4034 	.ctr = raid_ctr,
4035 	.dtr = raid_dtr,
4036 	.map = raid_map,
4037 	.status = raid_status,
4038 	.message = raid_message,
4039 	.iterate_devices = raid_iterate_devices,
4040 	.io_hints = raid_io_hints,
4041 	.postsuspend = raid_postsuspend,
4042 	.preresume = raid_preresume,
4043 	.resume = raid_resume,
4044 };
4045 
4046 static int __init dm_raid_init(void)
4047 {
4048 	DMINFO("Loading target version %u.%u.%u",
4049 	       raid_target.version[0],
4050 	       raid_target.version[1],
4051 	       raid_target.version[2]);
4052 	return dm_register_target(&raid_target);
4053 }
4054 
4055 static void __exit dm_raid_exit(void)
4056 {
4057 	dm_unregister_target(&raid_target);
4058 }
4059 
4060 module_init(dm_raid_init);
4061 module_exit(dm_raid_exit);
4062 
4063 module_param(devices_handle_discard_safely, bool, 0644);
4064 MODULE_PARM_DESC(devices_handle_discard_safely,
4065 		 "Set to Y if all devices in each array reliably return zeroes on reads from discarded regions");
4066 
4067 MODULE_DESCRIPTION(DM_NAME " raid0/1/10/4/5/6 target");
4068 MODULE_ALIAS("dm-raid0");
4069 MODULE_ALIAS("dm-raid1");
4070 MODULE_ALIAS("dm-raid10");
4071 MODULE_ALIAS("dm-raid4");
4072 MODULE_ALIAS("dm-raid5");
4073 MODULE_ALIAS("dm-raid6");
4074 MODULE_AUTHOR("Neil Brown <dm-devel@redhat.com>");
4075 MODULE_AUTHOR("Heinz Mauelshagen <dm-devel@redhat.com>");
4076 MODULE_LICENSE("GPL");
4077