xref: /linux/drivers/md/dm-raid.c (revision c79c3c34f75d72a066e292b10aa50fc758c97c89)
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 
1857 	default:
1858 		break;
1859 	}
1860 
1861 	rs->ti->error = "takeover not possible";
1862 	return -EINVAL;
1863 }
1864 
1865 /* True if @rs requested to be taken over */
1866 static bool rs_takeover_requested(struct raid_set *rs)
1867 {
1868 	return rs->md.new_level != rs->md.level;
1869 }
1870 
1871 /* True if @rs is requested to reshape by ctr */
1872 static bool rs_reshape_requested(struct raid_set *rs)
1873 {
1874 	bool change;
1875 	struct mddev *mddev = &rs->md;
1876 
1877 	if (rs_takeover_requested(rs))
1878 		return false;
1879 
1880 	if (rs_is_raid0(rs))
1881 		return false;
1882 
1883 	change = mddev->new_layout != mddev->layout ||
1884 		 mddev->new_chunk_sectors != mddev->chunk_sectors ||
1885 		 rs->delta_disks;
1886 
1887 	/* Historical case to support raid1 reshape without delta disks */
1888 	if (rs_is_raid1(rs)) {
1889 		if (rs->delta_disks)
1890 			return !!rs->delta_disks;
1891 
1892 		return !change &&
1893 		       mddev->raid_disks != rs->raid_disks;
1894 	}
1895 
1896 	if (rs_is_raid10(rs))
1897 		return change &&
1898 		       !__is_raid10_far(mddev->new_layout) &&
1899 		       rs->delta_disks >= 0;
1900 
1901 	return change;
1902 }
1903 
1904 /*  Features */
1905 #define	FEATURE_FLAG_SUPPORTS_V190	0x1 /* Supports extended superblock */
1906 
1907 /* State flags for sb->flags */
1908 #define	SB_FLAG_RESHAPE_ACTIVE		0x1
1909 #define	SB_FLAG_RESHAPE_BACKWARDS	0x2
1910 
1911 /*
1912  * This structure is never routinely used by userspace, unlike md superblocks.
1913  * Devices with this superblock should only ever be accessed via device-mapper.
1914  */
1915 #define DM_RAID_MAGIC 0x64526D44
1916 struct dm_raid_superblock {
1917 	__le32 magic;		/* "DmRd" */
1918 	__le32 compat_features;	/* Used to indicate compatible features (like 1.9.0 ondisk metadata extension) */
1919 
1920 	__le32 num_devices;	/* Number of devices in this raid set. (Max 64) */
1921 	__le32 array_position;	/* The position of this drive in the raid set */
1922 
1923 	__le64 events;		/* Incremented by md when superblock updated */
1924 	__le64 failed_devices;	/* Pre 1.9.0 part of bit field of devices to */
1925 				/* indicate failures (see extension below) */
1926 
1927 	/*
1928 	 * This offset tracks the progress of the repair or replacement of
1929 	 * an individual drive.
1930 	 */
1931 	__le64 disk_recovery_offset;
1932 
1933 	/*
1934 	 * This offset tracks the progress of the initial raid set
1935 	 * synchronisation/parity calculation.
1936 	 */
1937 	__le64 array_resync_offset;
1938 
1939 	/*
1940 	 * raid characteristics
1941 	 */
1942 	__le32 level;
1943 	__le32 layout;
1944 	__le32 stripe_sectors;
1945 
1946 	/********************************************************************
1947 	 * BELOW FOLLOW V1.9.0 EXTENSIONS TO THE PRISTINE SUPERBLOCK FORMAT!!!
1948 	 *
1949 	 * FEATURE_FLAG_SUPPORTS_V190 in the compat_features member indicates that those exist
1950 	 */
1951 
1952 	__le32 flags; /* Flags defining array states for reshaping */
1953 
1954 	/*
1955 	 * This offset tracks the progress of a raid
1956 	 * set reshape in order to be able to restart it
1957 	 */
1958 	__le64 reshape_position;
1959 
1960 	/*
1961 	 * These define the properties of the array in case of an interrupted reshape
1962 	 */
1963 	__le32 new_level;
1964 	__le32 new_layout;
1965 	__le32 new_stripe_sectors;
1966 	__le32 delta_disks;
1967 
1968 	__le64 array_sectors; /* Array size in sectors */
1969 
1970 	/*
1971 	 * Sector offsets to data on devices (reshaping).
1972 	 * Needed to support out of place reshaping, thus
1973 	 * not writing over any stripes whilst converting
1974 	 * them from old to new layout
1975 	 */
1976 	__le64 data_offset;
1977 	__le64 new_data_offset;
1978 
1979 	__le64 sectors; /* Used device size in sectors */
1980 
1981 	/*
1982 	 * Additonal Bit field of devices indicating failures to support
1983 	 * up to 256 devices with the 1.9.0 on-disk metadata format
1984 	 */
1985 	__le64 extended_failed_devices[DISKS_ARRAY_ELEMS - 1];
1986 
1987 	__le32 incompat_features;	/* Used to indicate any incompatible features */
1988 
1989 	/* Always set rest up to logical block size to 0 when writing (see get_metadata_device() below). */
1990 } __packed;
1991 
1992 /*
1993  * Check for reshape constraints on raid set @rs:
1994  *
1995  * - reshape function non-existent
1996  * - degraded set
1997  * - ongoing recovery
1998  * - ongoing reshape
1999  *
2000  * Returns 0 if none or -EPERM if given constraint
2001  * and error message reference in @errmsg
2002  */
2003 static int rs_check_reshape(struct raid_set *rs)
2004 {
2005 	struct mddev *mddev = &rs->md;
2006 
2007 	if (!mddev->pers || !mddev->pers->check_reshape)
2008 		rs->ti->error = "Reshape not supported";
2009 	else if (mddev->degraded)
2010 		rs->ti->error = "Can't reshape degraded raid set";
2011 	else if (rs_is_recovering(rs))
2012 		rs->ti->error = "Convert request on recovering raid set prohibited";
2013 	else if (rs_is_reshaping(rs))
2014 		rs->ti->error = "raid set already reshaping!";
2015 	else if (!(rs_is_raid1(rs) || rs_is_raid10(rs) || rs_is_raid456(rs)))
2016 		rs->ti->error = "Reshaping only supported for raid1/4/5/6/10";
2017 	else
2018 		return 0;
2019 
2020 	return -EPERM;
2021 }
2022 
2023 static int read_disk_sb(struct md_rdev *rdev, int size, bool force_reload)
2024 {
2025 	BUG_ON(!rdev->sb_page);
2026 
2027 	if (rdev->sb_loaded && !force_reload)
2028 		return 0;
2029 
2030 	rdev->sb_loaded = 0;
2031 
2032 	if (!sync_page_io(rdev, 0, size, rdev->sb_page, REQ_OP_READ, 0, true)) {
2033 		DMERR("Failed to read superblock of device at position %d",
2034 		      rdev->raid_disk);
2035 		md_error(rdev->mddev, rdev);
2036 		set_bit(Faulty, &rdev->flags);
2037 		return -EIO;
2038 	}
2039 
2040 	rdev->sb_loaded = 1;
2041 
2042 	return 0;
2043 }
2044 
2045 static void sb_retrieve_failed_devices(struct dm_raid_superblock *sb, uint64_t *failed_devices)
2046 {
2047 	failed_devices[0] = le64_to_cpu(sb->failed_devices);
2048 	memset(failed_devices + 1, 0, sizeof(sb->extended_failed_devices));
2049 
2050 	if (le32_to_cpu(sb->compat_features) & FEATURE_FLAG_SUPPORTS_V190) {
2051 		int i = ARRAY_SIZE(sb->extended_failed_devices);
2052 
2053 		while (i--)
2054 			failed_devices[i+1] = le64_to_cpu(sb->extended_failed_devices[i]);
2055 	}
2056 }
2057 
2058 static void sb_update_failed_devices(struct dm_raid_superblock *sb, uint64_t *failed_devices)
2059 {
2060 	int i = ARRAY_SIZE(sb->extended_failed_devices);
2061 
2062 	sb->failed_devices = cpu_to_le64(failed_devices[0]);
2063 	while (i--)
2064 		sb->extended_failed_devices[i] = cpu_to_le64(failed_devices[i+1]);
2065 }
2066 
2067 /*
2068  * Synchronize the superblock members with the raid set properties
2069  *
2070  * All superblock data is little endian.
2071  */
2072 static void super_sync(struct mddev *mddev, struct md_rdev *rdev)
2073 {
2074 	bool update_failed_devices = false;
2075 	unsigned int i;
2076 	uint64_t failed_devices[DISKS_ARRAY_ELEMS];
2077 	struct dm_raid_superblock *sb;
2078 	struct raid_set *rs = container_of(mddev, struct raid_set, md);
2079 
2080 	/* No metadata device, no superblock */
2081 	if (!rdev->meta_bdev)
2082 		return;
2083 
2084 	BUG_ON(!rdev->sb_page);
2085 
2086 	sb = page_address(rdev->sb_page);
2087 
2088 	sb_retrieve_failed_devices(sb, failed_devices);
2089 
2090 	for (i = 0; i < rs->raid_disks; i++)
2091 		if (!rs->dev[i].data_dev || test_bit(Faulty, &rs->dev[i].rdev.flags)) {
2092 			update_failed_devices = true;
2093 			set_bit(i, (void *) failed_devices);
2094 		}
2095 
2096 	if (update_failed_devices)
2097 		sb_update_failed_devices(sb, failed_devices);
2098 
2099 	sb->magic = cpu_to_le32(DM_RAID_MAGIC);
2100 	sb->compat_features = cpu_to_le32(FEATURE_FLAG_SUPPORTS_V190);
2101 
2102 	sb->num_devices = cpu_to_le32(mddev->raid_disks);
2103 	sb->array_position = cpu_to_le32(rdev->raid_disk);
2104 
2105 	sb->events = cpu_to_le64(mddev->events);
2106 
2107 	sb->disk_recovery_offset = cpu_to_le64(rdev->recovery_offset);
2108 	sb->array_resync_offset = cpu_to_le64(mddev->recovery_cp);
2109 
2110 	sb->level = cpu_to_le32(mddev->level);
2111 	sb->layout = cpu_to_le32(mddev->layout);
2112 	sb->stripe_sectors = cpu_to_le32(mddev->chunk_sectors);
2113 
2114 	/********************************************************************
2115 	 * BELOW FOLLOW V1.9.0 EXTENSIONS TO THE PRISTINE SUPERBLOCK FORMAT!!!
2116 	 *
2117 	 * FEATURE_FLAG_SUPPORTS_V190 in the compat_features member indicates that those exist
2118 	 */
2119 	sb->new_level = cpu_to_le32(mddev->new_level);
2120 	sb->new_layout = cpu_to_le32(mddev->new_layout);
2121 	sb->new_stripe_sectors = cpu_to_le32(mddev->new_chunk_sectors);
2122 
2123 	sb->delta_disks = cpu_to_le32(mddev->delta_disks);
2124 
2125 	smp_rmb(); /* Make sure we access most recent reshape position */
2126 	sb->reshape_position = cpu_to_le64(mddev->reshape_position);
2127 	if (le64_to_cpu(sb->reshape_position) != MaxSector) {
2128 		/* Flag ongoing reshape */
2129 		sb->flags |= cpu_to_le32(SB_FLAG_RESHAPE_ACTIVE);
2130 
2131 		if (mddev->delta_disks < 0 || mddev->reshape_backwards)
2132 			sb->flags |= cpu_to_le32(SB_FLAG_RESHAPE_BACKWARDS);
2133 	} else {
2134 		/* Clear reshape flags */
2135 		sb->flags &= ~(cpu_to_le32(SB_FLAG_RESHAPE_ACTIVE|SB_FLAG_RESHAPE_BACKWARDS));
2136 	}
2137 
2138 	sb->array_sectors = cpu_to_le64(mddev->array_sectors);
2139 	sb->data_offset = cpu_to_le64(rdev->data_offset);
2140 	sb->new_data_offset = cpu_to_le64(rdev->new_data_offset);
2141 	sb->sectors = cpu_to_le64(rdev->sectors);
2142 	sb->incompat_features = cpu_to_le32(0);
2143 
2144 	/* Zero out the rest of the payload after the size of the superblock */
2145 	memset(sb + 1, 0, rdev->sb_size - sizeof(*sb));
2146 }
2147 
2148 /*
2149  * super_load
2150  *
2151  * This function creates a superblock if one is not found on the device
2152  * and will decide which superblock to use if there's a choice.
2153  *
2154  * Return: 1 if use rdev, 0 if use refdev, -Exxx otherwise
2155  */
2156 static int super_load(struct md_rdev *rdev, struct md_rdev *refdev)
2157 {
2158 	int r;
2159 	struct dm_raid_superblock *sb;
2160 	struct dm_raid_superblock *refsb;
2161 	uint64_t events_sb, events_refsb;
2162 
2163 	r = read_disk_sb(rdev, rdev->sb_size, false);
2164 	if (r)
2165 		return r;
2166 
2167 	sb = page_address(rdev->sb_page);
2168 
2169 	/*
2170 	 * Two cases that we want to write new superblocks and rebuild:
2171 	 * 1) New device (no matching magic number)
2172 	 * 2) Device specified for rebuild (!In_sync w/ offset == 0)
2173 	 */
2174 	if ((sb->magic != cpu_to_le32(DM_RAID_MAGIC)) ||
2175 	    (!test_bit(In_sync, &rdev->flags) && !rdev->recovery_offset)) {
2176 		super_sync(rdev->mddev, rdev);
2177 
2178 		set_bit(FirstUse, &rdev->flags);
2179 		sb->compat_features = cpu_to_le32(FEATURE_FLAG_SUPPORTS_V190);
2180 
2181 		/* Force writing of superblocks to disk */
2182 		set_bit(MD_SB_CHANGE_DEVS, &rdev->mddev->sb_flags);
2183 
2184 		/* Any superblock is better than none, choose that if given */
2185 		return refdev ? 0 : 1;
2186 	}
2187 
2188 	if (!refdev)
2189 		return 1;
2190 
2191 	events_sb = le64_to_cpu(sb->events);
2192 
2193 	refsb = page_address(refdev->sb_page);
2194 	events_refsb = le64_to_cpu(refsb->events);
2195 
2196 	return (events_sb > events_refsb) ? 1 : 0;
2197 }
2198 
2199 static int super_init_validation(struct raid_set *rs, struct md_rdev *rdev)
2200 {
2201 	int role;
2202 	unsigned int d;
2203 	struct mddev *mddev = &rs->md;
2204 	uint64_t events_sb;
2205 	uint64_t failed_devices[DISKS_ARRAY_ELEMS];
2206 	struct dm_raid_superblock *sb;
2207 	uint32_t new_devs = 0, rebuild_and_new = 0, rebuilds = 0;
2208 	struct md_rdev *r;
2209 	struct dm_raid_superblock *sb2;
2210 
2211 	sb = page_address(rdev->sb_page);
2212 	events_sb = le64_to_cpu(sb->events);
2213 
2214 	/*
2215 	 * Initialise to 1 if this is a new superblock.
2216 	 */
2217 	mddev->events = events_sb ? : 1;
2218 
2219 	mddev->reshape_position = MaxSector;
2220 
2221 	mddev->raid_disks = le32_to_cpu(sb->num_devices);
2222 	mddev->level = le32_to_cpu(sb->level);
2223 	mddev->layout = le32_to_cpu(sb->layout);
2224 	mddev->chunk_sectors = le32_to_cpu(sb->stripe_sectors);
2225 
2226 	/*
2227 	 * Reshaping is supported, e.g. reshape_position is valid
2228 	 * in superblock and superblock content is authoritative.
2229 	 */
2230 	if (le32_to_cpu(sb->compat_features) & FEATURE_FLAG_SUPPORTS_V190) {
2231 		/* Superblock is authoritative wrt given raid set layout! */
2232 		mddev->new_level = le32_to_cpu(sb->new_level);
2233 		mddev->new_layout = le32_to_cpu(sb->new_layout);
2234 		mddev->new_chunk_sectors = le32_to_cpu(sb->new_stripe_sectors);
2235 		mddev->delta_disks = le32_to_cpu(sb->delta_disks);
2236 		mddev->array_sectors = le64_to_cpu(sb->array_sectors);
2237 
2238 		/* raid was reshaping and got interrupted */
2239 		if (le32_to_cpu(sb->flags) & SB_FLAG_RESHAPE_ACTIVE) {
2240 			if (test_bit(__CTR_FLAG_DELTA_DISKS, &rs->ctr_flags)) {
2241 				DMERR("Reshape requested but raid set is still reshaping");
2242 				return -EINVAL;
2243 			}
2244 
2245 			if (mddev->delta_disks < 0 ||
2246 			    (!mddev->delta_disks && (le32_to_cpu(sb->flags) & SB_FLAG_RESHAPE_BACKWARDS)))
2247 				mddev->reshape_backwards = 1;
2248 			else
2249 				mddev->reshape_backwards = 0;
2250 
2251 			mddev->reshape_position = le64_to_cpu(sb->reshape_position);
2252 			rs->raid_type = get_raid_type_by_ll(mddev->level, mddev->layout);
2253 		}
2254 
2255 	} else {
2256 		/*
2257 		 * No takeover/reshaping, because we don't have the extended v1.9.0 metadata
2258 		 */
2259 		struct raid_type *rt_cur = get_raid_type_by_ll(mddev->level, mddev->layout);
2260 		struct raid_type *rt_new = get_raid_type_by_ll(mddev->new_level, mddev->new_layout);
2261 
2262 		if (rs_takeover_requested(rs)) {
2263 			if (rt_cur && rt_new)
2264 				DMERR("Takeover raid sets from %s to %s not yet supported by metadata. (raid level change)",
2265 				      rt_cur->name, rt_new->name);
2266 			else
2267 				DMERR("Takeover raid sets not yet supported by metadata. (raid level change)");
2268 			return -EINVAL;
2269 		} else if (rs_reshape_requested(rs)) {
2270 			DMERR("Reshaping raid sets not yet supported by metadata. (raid layout change keeping level)");
2271 			if (mddev->layout != mddev->new_layout) {
2272 				if (rt_cur && rt_new)
2273 					DMERR("	 current layout %s vs new layout %s",
2274 					      rt_cur->name, rt_new->name);
2275 				else
2276 					DMERR("	 current layout 0x%X vs new layout 0x%X",
2277 					      le32_to_cpu(sb->layout), mddev->new_layout);
2278 			}
2279 			if (mddev->chunk_sectors != mddev->new_chunk_sectors)
2280 				DMERR("	 current stripe sectors %u vs new stripe sectors %u",
2281 				      mddev->chunk_sectors, mddev->new_chunk_sectors);
2282 			if (rs->delta_disks)
2283 				DMERR("	 current %u disks vs new %u disks",
2284 				      mddev->raid_disks, mddev->raid_disks + rs->delta_disks);
2285 			if (rs_is_raid10(rs)) {
2286 				DMERR("	 Old layout: %s w/ %u copies",
2287 				      raid10_md_layout_to_format(mddev->layout),
2288 				      raid10_md_layout_to_copies(mddev->layout));
2289 				DMERR("	 New layout: %s w/ %u copies",
2290 				      raid10_md_layout_to_format(mddev->new_layout),
2291 				      raid10_md_layout_to_copies(mddev->new_layout));
2292 			}
2293 			return -EINVAL;
2294 		}
2295 
2296 		DMINFO("Discovered old metadata format; upgrading to extended metadata format");
2297 	}
2298 
2299 	if (!test_bit(__CTR_FLAG_NOSYNC, &rs->ctr_flags))
2300 		mddev->recovery_cp = le64_to_cpu(sb->array_resync_offset);
2301 
2302 	/*
2303 	 * During load, we set FirstUse if a new superblock was written.
2304 	 * There are two reasons we might not have a superblock:
2305 	 * 1) The raid set is brand new - in which case, all of the
2306 	 *    devices must have their In_sync bit set.	Also,
2307 	 *    recovery_cp must be 0, unless forced.
2308 	 * 2) This is a new device being added to an old raid set
2309 	 *    and the new device needs to be rebuilt - in which
2310 	 *    case the In_sync bit will /not/ be set and
2311 	 *    recovery_cp must be MaxSector.
2312 	 * 3) This is/are a new device(s) being added to an old
2313 	 *    raid set during takeover to a higher raid level
2314 	 *    to provide capacity for redundancy or during reshape
2315 	 *    to add capacity to grow the raid set.
2316 	 */
2317 	d = 0;
2318 	rdev_for_each(r, mddev) {
2319 		if (test_bit(Journal, &rdev->flags))
2320 			continue;
2321 
2322 		if (test_bit(FirstUse, &r->flags))
2323 			new_devs++;
2324 
2325 		if (!test_bit(In_sync, &r->flags)) {
2326 			DMINFO("Device %d specified for rebuild; clearing superblock",
2327 				r->raid_disk);
2328 			rebuilds++;
2329 
2330 			if (test_bit(FirstUse, &r->flags))
2331 				rebuild_and_new++;
2332 		}
2333 
2334 		d++;
2335 	}
2336 
2337 	if (new_devs == rs->raid_disks || !rebuilds) {
2338 		/* Replace a broken device */
2339 		if (new_devs == rs->raid_disks) {
2340 			DMINFO("Superblocks created for new raid set");
2341 			set_bit(MD_ARRAY_FIRST_USE, &mddev->flags);
2342 		} else if (new_devs != rebuilds &&
2343 			   new_devs != rs->delta_disks) {
2344 			DMERR("New device injected into existing raid set without "
2345 			      "'delta_disks' or 'rebuild' parameter specified");
2346 			return -EINVAL;
2347 		}
2348 	} else if (new_devs && new_devs != rebuilds) {
2349 		DMERR("%u 'rebuild' devices cannot be injected into"
2350 		      " a raid set with %u other first-time devices",
2351 		      rebuilds, new_devs);
2352 		return -EINVAL;
2353 	} else if (rebuilds) {
2354 		if (rebuild_and_new && rebuilds != rebuild_and_new) {
2355 			DMERR("new device%s provided without 'rebuild'",
2356 			      new_devs > 1 ? "s" : "");
2357 			return -EINVAL;
2358 		} else if (!test_bit(__CTR_FLAG_REBUILD, &rs->ctr_flags) && rs_is_recovering(rs)) {
2359 			DMERR("'rebuild' specified while raid set is not in-sync (recovery_cp=%llu)",
2360 			      (unsigned long long) mddev->recovery_cp);
2361 			return -EINVAL;
2362 		} else if (rs_is_reshaping(rs)) {
2363 			DMERR("'rebuild' specified while raid set is being reshaped (reshape_position=%llu)",
2364 			      (unsigned long long) mddev->reshape_position);
2365 			return -EINVAL;
2366 		}
2367 	}
2368 
2369 	/*
2370 	 * Now we set the Faulty bit for those devices that are
2371 	 * recorded in the superblock as failed.
2372 	 */
2373 	sb_retrieve_failed_devices(sb, failed_devices);
2374 	rdev_for_each(r, mddev) {
2375 		if (test_bit(Journal, &rdev->flags) ||
2376 		    !r->sb_page)
2377 			continue;
2378 		sb2 = page_address(r->sb_page);
2379 		sb2->failed_devices = 0;
2380 		memset(sb2->extended_failed_devices, 0, sizeof(sb2->extended_failed_devices));
2381 
2382 		/*
2383 		 * Check for any device re-ordering.
2384 		 */
2385 		if (!test_bit(FirstUse, &r->flags) && (r->raid_disk >= 0)) {
2386 			role = le32_to_cpu(sb2->array_position);
2387 			if (role < 0)
2388 				continue;
2389 
2390 			if (role != r->raid_disk) {
2391 				if (rs_is_raid10(rs) && __is_raid10_near(mddev->layout)) {
2392 					if (mddev->raid_disks % __raid10_near_copies(mddev->layout) ||
2393 					    rs->raid_disks % rs->raid10_copies) {
2394 						rs->ti->error =
2395 							"Cannot change raid10 near set to odd # of devices!";
2396 						return -EINVAL;
2397 					}
2398 
2399 					sb2->array_position = cpu_to_le32(r->raid_disk);
2400 
2401 				} else if (!(rs_is_raid10(rs) && rt_is_raid0(rs->raid_type)) &&
2402 					   !(rs_is_raid0(rs) && rt_is_raid10(rs->raid_type)) &&
2403 					   !rt_is_raid1(rs->raid_type)) {
2404 					rs->ti->error = "Cannot change device positions in raid set";
2405 					return -EINVAL;
2406 				}
2407 
2408 				DMINFO("raid device #%d now at position #%d", role, r->raid_disk);
2409 			}
2410 
2411 			/*
2412 			 * Partial recovery is performed on
2413 			 * returning failed devices.
2414 			 */
2415 			if (test_bit(role, (void *) failed_devices))
2416 				set_bit(Faulty, &r->flags);
2417 		}
2418 	}
2419 
2420 	return 0;
2421 }
2422 
2423 static int super_validate(struct raid_set *rs, struct md_rdev *rdev)
2424 {
2425 	struct mddev *mddev = &rs->md;
2426 	struct dm_raid_superblock *sb;
2427 
2428 	if (rs_is_raid0(rs) || !rdev->sb_page || rdev->raid_disk < 0)
2429 		return 0;
2430 
2431 	sb = page_address(rdev->sb_page);
2432 
2433 	/*
2434 	 * If mddev->events is not set, we know we have not yet initialized
2435 	 * the array.
2436 	 */
2437 	if (!mddev->events && super_init_validation(rs, rdev))
2438 		return -EINVAL;
2439 
2440 	if (le32_to_cpu(sb->compat_features) &&
2441 	    le32_to_cpu(sb->compat_features) != FEATURE_FLAG_SUPPORTS_V190) {
2442 		rs->ti->error = "Unable to assemble array: Unknown flag(s) in compatible feature flags";
2443 		return -EINVAL;
2444 	}
2445 
2446 	if (sb->incompat_features) {
2447 		rs->ti->error = "Unable to assemble array: No incompatible feature flags supported yet";
2448 		return -EINVAL;
2449 	}
2450 
2451 	/* Enable bitmap creation on @rs unless no metadevs or raid0 or journaled raid4/5/6 set. */
2452 	mddev->bitmap_info.offset = (rt_is_raid0(rs->raid_type) || rs->journal_dev.dev) ? 0 : to_sector(4096);
2453 	mddev->bitmap_info.default_offset = mddev->bitmap_info.offset;
2454 
2455 	if (!test_and_clear_bit(FirstUse, &rdev->flags)) {
2456 		/*
2457 		 * Retrieve rdev size stored in superblock to be prepared for shrink.
2458 		 * Check extended superblock members are present otherwise the size
2459 		 * will not be set!
2460 		 */
2461 		if (le32_to_cpu(sb->compat_features) & FEATURE_FLAG_SUPPORTS_V190)
2462 			rdev->sectors = le64_to_cpu(sb->sectors);
2463 
2464 		rdev->recovery_offset = le64_to_cpu(sb->disk_recovery_offset);
2465 		if (rdev->recovery_offset == MaxSector)
2466 			set_bit(In_sync, &rdev->flags);
2467 		/*
2468 		 * If no reshape in progress -> we're recovering single
2469 		 * disk(s) and have to set the device(s) to out-of-sync
2470 		 */
2471 		else if (!rs_is_reshaping(rs))
2472 			clear_bit(In_sync, &rdev->flags); /* Mandatory for recovery */
2473 	}
2474 
2475 	/*
2476 	 * If a device comes back, set it as not In_sync and no longer faulty.
2477 	 */
2478 	if (test_and_clear_bit(Faulty, &rdev->flags)) {
2479 		rdev->recovery_offset = 0;
2480 		clear_bit(In_sync, &rdev->flags);
2481 		rdev->saved_raid_disk = rdev->raid_disk;
2482 	}
2483 
2484 	/* Reshape support -> restore repective data offsets */
2485 	rdev->data_offset = le64_to_cpu(sb->data_offset);
2486 	rdev->new_data_offset = le64_to_cpu(sb->new_data_offset);
2487 
2488 	return 0;
2489 }
2490 
2491 /*
2492  * Analyse superblocks and select the freshest.
2493  */
2494 static int analyse_superblocks(struct dm_target *ti, struct raid_set *rs)
2495 {
2496 	int r;
2497 	struct md_rdev *rdev, *freshest;
2498 	struct mddev *mddev = &rs->md;
2499 
2500 	freshest = NULL;
2501 	rdev_for_each(rdev, mddev) {
2502 		if (test_bit(Journal, &rdev->flags))
2503 			continue;
2504 
2505 		if (!rdev->meta_bdev)
2506 			continue;
2507 
2508 		/* Set superblock offset/size for metadata device. */
2509 		rdev->sb_start = 0;
2510 		rdev->sb_size = bdev_logical_block_size(rdev->meta_bdev);
2511 		if (rdev->sb_size < sizeof(struct dm_raid_superblock) || rdev->sb_size > PAGE_SIZE) {
2512 			DMERR("superblock size of a logical block is no longer valid");
2513 			return -EINVAL;
2514 		}
2515 
2516 		/*
2517 		 * Skipping super_load due to CTR_FLAG_SYNC will cause
2518 		 * the array to undergo initialization again as
2519 		 * though it were new.	This is the intended effect
2520 		 * of the "sync" directive.
2521 		 *
2522 		 * With reshaping capability added, we must ensure that
2523 		 * that the "sync" directive is disallowed during the reshape.
2524 		 */
2525 		if (test_bit(__CTR_FLAG_SYNC, &rs->ctr_flags))
2526 			continue;
2527 
2528 		r = super_load(rdev, freshest);
2529 
2530 		switch (r) {
2531 		case 1:
2532 			freshest = rdev;
2533 			break;
2534 		case 0:
2535 			break;
2536 		default:
2537 			/* This is a failure to read the superblock from the metadata device. */
2538 			/*
2539 			 * We have to keep any raid0 data/metadata device pairs or
2540 			 * the MD raid0 personality will fail to start the array.
2541 			 */
2542 			if (rs_is_raid0(rs))
2543 				continue;
2544 
2545 			/*
2546 			 * We keep the dm_devs to be able to emit the device tuple
2547 			 * properly on the table line in raid_status() (rather than
2548 			 * mistakenly acting as if '- -' got passed into the constructor).
2549 			 *
2550 			 * The rdev has to stay on the same_set list to allow for
2551 			 * the attempt to restore faulty devices on second resume.
2552 			 */
2553 			rdev->raid_disk = rdev->saved_raid_disk = -1;
2554 			break;
2555 		}
2556 	}
2557 
2558 	if (!freshest)
2559 		return 0;
2560 
2561 	/*
2562 	 * Validation of the freshest device provides the source of
2563 	 * validation for the remaining devices.
2564 	 */
2565 	rs->ti->error = "Unable to assemble array: Invalid superblocks";
2566 	if (super_validate(rs, freshest))
2567 		return -EINVAL;
2568 
2569 	if (validate_raid_redundancy(rs)) {
2570 		rs->ti->error = "Insufficient redundancy to activate array";
2571 		return -EINVAL;
2572 	}
2573 
2574 	rdev_for_each(rdev, mddev)
2575 		if (!test_bit(Journal, &rdev->flags) &&
2576 		    rdev != freshest &&
2577 		    super_validate(rs, rdev))
2578 			return -EINVAL;
2579 	return 0;
2580 }
2581 
2582 /*
2583  * Adjust data_offset and new_data_offset on all disk members of @rs
2584  * for out of place reshaping if requested by contructor
2585  *
2586  * We need free space at the beginning of each raid disk for forward
2587  * and at the end for backward reshapes which userspace has to provide
2588  * via remapping/reordering of space.
2589  */
2590 static int rs_adjust_data_offsets(struct raid_set *rs)
2591 {
2592 	sector_t data_offset = 0, new_data_offset = 0;
2593 	struct md_rdev *rdev;
2594 
2595 	/* Constructor did not request data offset change */
2596 	if (!test_bit(__CTR_FLAG_DATA_OFFSET, &rs->ctr_flags)) {
2597 		if (!rs_is_reshapable(rs))
2598 			goto out;
2599 
2600 		return 0;
2601 	}
2602 
2603 	/* HM FIXME: get In_Sync raid_dev? */
2604 	rdev = &rs->dev[0].rdev;
2605 
2606 	if (rs->delta_disks < 0) {
2607 		/*
2608 		 * Removing disks (reshaping backwards):
2609 		 *
2610 		 * - before reshape: data is at offset 0 and free space
2611 		 *		     is at end of each component LV
2612 		 *
2613 		 * - after reshape: data is at offset rs->data_offset != 0 on each component LV
2614 		 */
2615 		data_offset = 0;
2616 		new_data_offset = rs->data_offset;
2617 
2618 	} else if (rs->delta_disks > 0) {
2619 		/*
2620 		 * Adding disks (reshaping forwards):
2621 		 *
2622 		 * - before reshape: data is at offset rs->data_offset != 0 and
2623 		 *		     free space is at begin of each component LV
2624 		 *
2625 		 * - after reshape: data is at offset 0 on each component LV
2626 		 */
2627 		data_offset = rs->data_offset;
2628 		new_data_offset = 0;
2629 
2630 	} else {
2631 		/*
2632 		 * User space passes in 0 for data offset after having removed reshape space
2633 		 *
2634 		 * - or - (data offset != 0)
2635 		 *
2636 		 * Changing RAID layout or chunk size -> toggle offsets
2637 		 *
2638 		 * - before reshape: data is at offset rs->data_offset 0 and
2639 		 *		     free space is at end of each component LV
2640 		 *		     -or-
2641 		 *                   data is at offset rs->data_offset != 0 and
2642 		 *		     free space is at begin of each component LV
2643 		 *
2644 		 * - after reshape: data is at offset 0 if it was at offset != 0
2645 		 *                  or at offset != 0 if it was at offset 0
2646 		 *                  on each component LV
2647 		 *
2648 		 */
2649 		data_offset = rs->data_offset ? rdev->data_offset : 0;
2650 		new_data_offset = data_offset ? 0 : rs->data_offset;
2651 		set_bit(RT_FLAG_UPDATE_SBS, &rs->runtime_flags);
2652 	}
2653 
2654 	/*
2655 	 * Make sure we got a minimum amount of free sectors per device
2656 	 */
2657 	if (rs->data_offset &&
2658 	    to_sector(i_size_read(rdev->bdev->bd_inode)) - rs->md.dev_sectors < MIN_FREE_RESHAPE_SPACE) {
2659 		rs->ti->error = data_offset ? "No space for forward reshape" :
2660 					      "No space for backward reshape";
2661 		return -ENOSPC;
2662 	}
2663 out:
2664 	/*
2665 	 * Raise recovery_cp in case data_offset != 0 to
2666 	 * avoid false recovery positives in the constructor.
2667 	 */
2668 	if (rs->md.recovery_cp < rs->md.dev_sectors)
2669 		rs->md.recovery_cp += rs->dev[0].rdev.data_offset;
2670 
2671 	/* Adjust data offsets on all rdevs but on any raid4/5/6 journal device */
2672 	rdev_for_each(rdev, &rs->md) {
2673 		if (!test_bit(Journal, &rdev->flags)) {
2674 			rdev->data_offset = data_offset;
2675 			rdev->new_data_offset = new_data_offset;
2676 		}
2677 	}
2678 
2679 	return 0;
2680 }
2681 
2682 /* Userpace reordered disks -> adjust raid_disk indexes in @rs */
2683 static void __reorder_raid_disk_indexes(struct raid_set *rs)
2684 {
2685 	int i = 0;
2686 	struct md_rdev *rdev;
2687 
2688 	rdev_for_each(rdev, &rs->md) {
2689 		if (!test_bit(Journal, &rdev->flags)) {
2690 			rdev->raid_disk = i++;
2691 			rdev->saved_raid_disk = rdev->new_raid_disk = -1;
2692 		}
2693 	}
2694 }
2695 
2696 /*
2697  * Setup @rs for takeover by a different raid level
2698  */
2699 static int rs_setup_takeover(struct raid_set *rs)
2700 {
2701 	struct mddev *mddev = &rs->md;
2702 	struct md_rdev *rdev;
2703 	unsigned int d = mddev->raid_disks = rs->raid_disks;
2704 	sector_t new_data_offset = rs->dev[0].rdev.data_offset ? 0 : rs->data_offset;
2705 
2706 	if (rt_is_raid10(rs->raid_type)) {
2707 		if (rs_is_raid0(rs)) {
2708 			/* Userpace reordered disks -> adjust raid_disk indexes */
2709 			__reorder_raid_disk_indexes(rs);
2710 
2711 			/* raid0 -> raid10_far layout */
2712 			mddev->layout = raid10_format_to_md_layout(rs, ALGORITHM_RAID10_FAR,
2713 								   rs->raid10_copies);
2714 		} else if (rs_is_raid1(rs))
2715 			/* raid1 -> raid10_near layout */
2716 			mddev->layout = raid10_format_to_md_layout(rs, ALGORITHM_RAID10_NEAR,
2717 								   rs->raid_disks);
2718 		else
2719 			return -EINVAL;
2720 
2721 	}
2722 
2723 	clear_bit(MD_ARRAY_FIRST_USE, &mddev->flags);
2724 	mddev->recovery_cp = MaxSector;
2725 
2726 	while (d--) {
2727 		rdev = &rs->dev[d].rdev;
2728 
2729 		if (test_bit(d, (void *) rs->rebuild_disks)) {
2730 			clear_bit(In_sync, &rdev->flags);
2731 			clear_bit(Faulty, &rdev->flags);
2732 			mddev->recovery_cp = rdev->recovery_offset = 0;
2733 			/* Bitmap has to be created when we do an "up" takeover */
2734 			set_bit(MD_ARRAY_FIRST_USE, &mddev->flags);
2735 		}
2736 
2737 		rdev->new_data_offset = new_data_offset;
2738 	}
2739 
2740 	return 0;
2741 }
2742 
2743 /* Prepare @rs for reshape */
2744 static int rs_prepare_reshape(struct raid_set *rs)
2745 {
2746 	bool reshape;
2747 	struct mddev *mddev = &rs->md;
2748 
2749 	if (rs_is_raid10(rs)) {
2750 		if (rs->raid_disks != mddev->raid_disks &&
2751 		    __is_raid10_near(mddev->layout) &&
2752 		    rs->raid10_copies &&
2753 		    rs->raid10_copies != __raid10_near_copies(mddev->layout)) {
2754 			/*
2755 			 * raid disk have to be multiple of data copies to allow this conversion,
2756 			 *
2757 			 * This is actually not a reshape it is a
2758 			 * rebuild of any additional mirrors per group
2759 			 */
2760 			if (rs->raid_disks % rs->raid10_copies) {
2761 				rs->ti->error = "Can't reshape raid10 mirror groups";
2762 				return -EINVAL;
2763 			}
2764 
2765 			/* Userpace reordered disks to add/remove mirrors -> adjust raid_disk indexes */
2766 			__reorder_raid_disk_indexes(rs);
2767 			mddev->layout = raid10_format_to_md_layout(rs, ALGORITHM_RAID10_NEAR,
2768 								   rs->raid10_copies);
2769 			mddev->new_layout = mddev->layout;
2770 			reshape = false;
2771 		} else
2772 			reshape = true;
2773 
2774 	} else if (rs_is_raid456(rs))
2775 		reshape = true;
2776 
2777 	else if (rs_is_raid1(rs)) {
2778 		if (rs->delta_disks) {
2779 			/* Process raid1 via delta_disks */
2780 			mddev->degraded = rs->delta_disks < 0 ? -rs->delta_disks : rs->delta_disks;
2781 			reshape = true;
2782 		} else {
2783 			/* Process raid1 without delta_disks */
2784 			mddev->raid_disks = rs->raid_disks;
2785 			reshape = false;
2786 		}
2787 	} else {
2788 		rs->ti->error = "Called with bogus raid type";
2789 		return -EINVAL;
2790 	}
2791 
2792 	if (reshape) {
2793 		set_bit(RT_FLAG_RESHAPE_RS, &rs->runtime_flags);
2794 		set_bit(RT_FLAG_UPDATE_SBS, &rs->runtime_flags);
2795 	} else if (mddev->raid_disks < rs->raid_disks)
2796 		/* Create new superblocks and bitmaps, if any new disks */
2797 		set_bit(RT_FLAG_UPDATE_SBS, &rs->runtime_flags);
2798 
2799 	return 0;
2800 }
2801 
2802 /* Get reshape sectors from data_offsets or raid set */
2803 static sector_t _get_reshape_sectors(struct raid_set *rs)
2804 {
2805 	struct md_rdev *rdev;
2806 	sector_t reshape_sectors = 0;
2807 
2808 	rdev_for_each(rdev, &rs->md)
2809 		if (!test_bit(Journal, &rdev->flags)) {
2810 			reshape_sectors = (rdev->data_offset > rdev->new_data_offset) ?
2811 					rdev->data_offset - rdev->new_data_offset :
2812 					rdev->new_data_offset - rdev->data_offset;
2813 			break;
2814 		}
2815 
2816 	return max(reshape_sectors, (sector_t) rs->data_offset);
2817 }
2818 
2819 /*
2820  *
2821  * - change raid layout
2822  * - change chunk size
2823  * - add disks
2824  * - remove disks
2825  */
2826 static int rs_setup_reshape(struct raid_set *rs)
2827 {
2828 	int r = 0;
2829 	unsigned int cur_raid_devs, d;
2830 	sector_t reshape_sectors = _get_reshape_sectors(rs);
2831 	struct mddev *mddev = &rs->md;
2832 	struct md_rdev *rdev;
2833 
2834 	mddev->delta_disks = rs->delta_disks;
2835 	cur_raid_devs = mddev->raid_disks;
2836 
2837 	/* Ignore impossible layout change whilst adding/removing disks */
2838 	if (mddev->delta_disks &&
2839 	    mddev->layout != mddev->new_layout) {
2840 		DMINFO("Ignoring invalid layout change with delta_disks=%d", rs->delta_disks);
2841 		mddev->new_layout = mddev->layout;
2842 	}
2843 
2844 	/*
2845 	 * Adjust array size:
2846 	 *
2847 	 * - in case of adding disk(s), array size has
2848 	 *   to grow after the disk adding reshape,
2849 	 *   which'll hapen in the event handler;
2850 	 *   reshape will happen forward, so space has to
2851 	 *   be available at the beginning of each disk
2852 	 *
2853 	 * - in case of removing disk(s), array size
2854 	 *   has to shrink before starting the reshape,
2855 	 *   which'll happen here;
2856 	 *   reshape will happen backward, so space has to
2857 	 *   be available at the end of each disk
2858 	 *
2859 	 * - data_offset and new_data_offset are
2860 	 *   adjusted for aforementioned out of place
2861 	 *   reshaping based on userspace passing in
2862 	 *   the "data_offset <sectors>" key/value
2863 	 *   pair via the constructor
2864 	 */
2865 
2866 	/* Add disk(s) */
2867 	if (rs->delta_disks > 0) {
2868 		/* Prepare disks for check in raid4/5/6/10 {check|start}_reshape */
2869 		for (d = cur_raid_devs; d < rs->raid_disks; d++) {
2870 			rdev = &rs->dev[d].rdev;
2871 			clear_bit(In_sync, &rdev->flags);
2872 
2873 			/*
2874 			 * save_raid_disk needs to be -1, or recovery_offset will be set to 0
2875 			 * by md, which'll store that erroneously in the superblock on reshape
2876 			 */
2877 			rdev->saved_raid_disk = -1;
2878 			rdev->raid_disk = d;
2879 
2880 			rdev->sectors = mddev->dev_sectors;
2881 			rdev->recovery_offset = rs_is_raid1(rs) ? 0 : MaxSector;
2882 		}
2883 
2884 		mddev->reshape_backwards = 0; /* adding disk(s) -> forward reshape */
2885 
2886 	/* Remove disk(s) */
2887 	} else if (rs->delta_disks < 0) {
2888 		r = rs_set_dev_and_array_sectors(rs, rs->ti->len, true);
2889 		mddev->reshape_backwards = 1; /* removing disk(s) -> backward reshape */
2890 
2891 	/* Change layout and/or chunk size */
2892 	} else {
2893 		/*
2894 		 * Reshape layout (e.g. raid5_ls -> raid5_n) and/or chunk size:
2895 		 *
2896 		 * keeping number of disks and do layout change ->
2897 		 *
2898 		 * toggle reshape_backward depending on data_offset:
2899 		 *
2900 		 * - free space upfront -> reshape forward
2901 		 *
2902 		 * - free space at the end -> reshape backward
2903 		 *
2904 		 *
2905 		 * This utilizes free reshape space avoiding the need
2906 		 * for userspace to move (parts of) LV segments in
2907 		 * case of layout/chunksize change  (for disk
2908 		 * adding/removing reshape space has to be at
2909 		 * the proper address (see above with delta_disks):
2910 		 *
2911 		 * add disk(s)   -> begin
2912 		 * remove disk(s)-> end
2913 		 */
2914 		mddev->reshape_backwards = rs->dev[0].rdev.data_offset ? 0 : 1;
2915 	}
2916 
2917 	/*
2918 	 * Adjust device size for forward reshape
2919 	 * because md_finish_reshape() reduces it.
2920 	 */
2921 	if (!mddev->reshape_backwards)
2922 		rdev_for_each(rdev, &rs->md)
2923 			if (!test_bit(Journal, &rdev->flags))
2924 				rdev->sectors += reshape_sectors;
2925 
2926 	return r;
2927 }
2928 
2929 /*
2930  * Enable/disable discard support on RAID set depending on
2931  * RAID level and discard properties of underlying RAID members.
2932  */
2933 static void configure_discard_support(struct raid_set *rs)
2934 {
2935 	int i;
2936 	bool raid456;
2937 	struct dm_target *ti = rs->ti;
2938 
2939 	/*
2940 	 * XXX: RAID level 4,5,6 require zeroing for safety.
2941 	 */
2942 	raid456 = rs_is_raid456(rs);
2943 
2944 	for (i = 0; i < rs->raid_disks; i++) {
2945 		struct request_queue *q;
2946 
2947 		if (!rs->dev[i].rdev.bdev)
2948 			continue;
2949 
2950 		q = bdev_get_queue(rs->dev[i].rdev.bdev);
2951 		if (!q || !blk_queue_discard(q))
2952 			return;
2953 
2954 		if (raid456) {
2955 			if (!devices_handle_discard_safely) {
2956 				DMERR("raid456 discard support disabled due to discard_zeroes_data uncertainty.");
2957 				DMERR("Set dm-raid.devices_handle_discard_safely=Y to override.");
2958 				return;
2959 			}
2960 		}
2961 	}
2962 
2963 	ti->num_discard_bios = 1;
2964 }
2965 
2966 /*
2967  * Construct a RAID0/1/10/4/5/6 mapping:
2968  * Args:
2969  *	<raid_type> <#raid_params> <raid_params>{0,}	\
2970  *	<#raid_devs> [<meta_dev1> <dev1>]{1,}
2971  *
2972  * <raid_params> varies by <raid_type>.	 See 'parse_raid_params' for
2973  * details on possible <raid_params>.
2974  *
2975  * Userspace is free to initialize the metadata devices, hence the superblocks to
2976  * enforce recreation based on the passed in table parameters.
2977  *
2978  */
2979 static int raid_ctr(struct dm_target *ti, unsigned int argc, char **argv)
2980 {
2981 	int r;
2982 	bool resize = false;
2983 	struct raid_type *rt;
2984 	unsigned int num_raid_params, num_raid_devs;
2985 	sector_t sb_array_sectors, rdev_sectors, reshape_sectors;
2986 	struct raid_set *rs = NULL;
2987 	const char *arg;
2988 	struct rs_layout rs_layout;
2989 	struct dm_arg_set as = { argc, argv }, as_nrd;
2990 	struct dm_arg _args[] = {
2991 		{ 0, as.argc, "Cannot understand number of raid parameters" },
2992 		{ 1, 254, "Cannot understand number of raid devices parameters" }
2993 	};
2994 
2995 	arg = dm_shift_arg(&as);
2996 	if (!arg) {
2997 		ti->error = "No arguments";
2998 		return -EINVAL;
2999 	}
3000 
3001 	rt = get_raid_type(arg);
3002 	if (!rt) {
3003 		ti->error = "Unrecognised raid_type";
3004 		return -EINVAL;
3005 	}
3006 
3007 	/* Must have <#raid_params> */
3008 	if (dm_read_arg_group(_args, &as, &num_raid_params, &ti->error))
3009 		return -EINVAL;
3010 
3011 	/* number of raid device tupples <meta_dev data_dev> */
3012 	as_nrd = as;
3013 	dm_consume_args(&as_nrd, num_raid_params);
3014 	_args[1].max = (as_nrd.argc - 1) / 2;
3015 	if (dm_read_arg(_args + 1, &as_nrd, &num_raid_devs, &ti->error))
3016 		return -EINVAL;
3017 
3018 	if (!__within_range(num_raid_devs, 1, MAX_RAID_DEVICES)) {
3019 		ti->error = "Invalid number of supplied raid devices";
3020 		return -EINVAL;
3021 	}
3022 
3023 	rs = raid_set_alloc(ti, rt, num_raid_devs);
3024 	if (IS_ERR(rs))
3025 		return PTR_ERR(rs);
3026 
3027 	r = parse_raid_params(rs, &as, num_raid_params);
3028 	if (r)
3029 		goto bad;
3030 
3031 	r = parse_dev_params(rs, &as);
3032 	if (r)
3033 		goto bad;
3034 
3035 	rs->md.sync_super = super_sync;
3036 
3037 	/*
3038 	 * Calculate ctr requested array and device sizes to allow
3039 	 * for superblock analysis needing device sizes defined.
3040 	 *
3041 	 * Any existing superblock will overwrite the array and device sizes
3042 	 */
3043 	r = rs_set_dev_and_array_sectors(rs, rs->ti->len, false);
3044 	if (r)
3045 		goto bad;
3046 
3047 	/* Memorize just calculated, potentially larger sizes to grow the raid set in preresume */
3048 	rs->array_sectors = rs->md.array_sectors;
3049 	rs->dev_sectors = rs->md.dev_sectors;
3050 
3051 	/*
3052 	 * Backup any new raid set level, layout, ...
3053 	 * requested to be able to compare to superblock
3054 	 * members for conversion decisions.
3055 	 */
3056 	rs_config_backup(rs, &rs_layout);
3057 
3058 	r = analyse_superblocks(ti, rs);
3059 	if (r)
3060 		goto bad;
3061 
3062 	/* All in-core metadata now as of current superblocks after calling analyse_superblocks() */
3063 	sb_array_sectors = rs->md.array_sectors;
3064 	rdev_sectors = __rdev_sectors(rs);
3065 	if (!rdev_sectors) {
3066 		ti->error = "Invalid rdev size";
3067 		r = -EINVAL;
3068 		goto bad;
3069 	}
3070 
3071 
3072 	reshape_sectors = _get_reshape_sectors(rs);
3073 	if (rs->dev_sectors != rdev_sectors) {
3074 		resize = (rs->dev_sectors != rdev_sectors - reshape_sectors);
3075 		if (rs->dev_sectors > rdev_sectors - reshape_sectors)
3076 			set_bit(RT_FLAG_RS_GROW, &rs->runtime_flags);
3077 	}
3078 
3079 	INIT_WORK(&rs->md.event_work, do_table_event);
3080 	ti->private = rs;
3081 	ti->num_flush_bios = 1;
3082 
3083 	/* Restore any requested new layout for conversion decision */
3084 	rs_config_restore(rs, &rs_layout);
3085 
3086 	/*
3087 	 * Now that we have any superblock metadata available,
3088 	 * check for new, recovering, reshaping, to be taken over,
3089 	 * to be reshaped or an existing, unchanged raid set to
3090 	 * run in sequence.
3091 	 */
3092 	if (test_bit(MD_ARRAY_FIRST_USE, &rs->md.flags)) {
3093 		/* A new raid6 set has to be recovered to ensure proper parity and Q-Syndrome */
3094 		if (rs_is_raid6(rs) &&
3095 		    test_bit(__CTR_FLAG_NOSYNC, &rs->ctr_flags)) {
3096 			ti->error = "'nosync' not allowed for new raid6 set";
3097 			r = -EINVAL;
3098 			goto bad;
3099 		}
3100 		rs_setup_recovery(rs, 0);
3101 		set_bit(RT_FLAG_UPDATE_SBS, &rs->runtime_flags);
3102 		rs_set_new(rs);
3103 	} else if (rs_is_recovering(rs)) {
3104 		/* A recovering raid set may be resized */
3105 		goto size_check;
3106 	} else if (rs_is_reshaping(rs)) {
3107 		/* Have to reject size change request during reshape */
3108 		if (resize) {
3109 			ti->error = "Can't resize a reshaping raid set";
3110 			r = -EPERM;
3111 			goto bad;
3112 		}
3113 		/* skip setup rs */
3114 	} else if (rs_takeover_requested(rs)) {
3115 		if (rs_is_reshaping(rs)) {
3116 			ti->error = "Can't takeover a reshaping raid set";
3117 			r = -EPERM;
3118 			goto bad;
3119 		}
3120 
3121 		/* We can't takeover a journaled raid4/5/6 */
3122 		if (test_bit(__CTR_FLAG_JOURNAL_DEV, &rs->ctr_flags)) {
3123 			ti->error = "Can't takeover a journaled raid4/5/6 set";
3124 			r = -EPERM;
3125 			goto bad;
3126 		}
3127 
3128 		/*
3129 		 * If a takeover is needed, userspace sets any additional
3130 		 * devices to rebuild and we can check for a valid request here.
3131 		 *
3132 		 * If acceptible, set the level to the new requested
3133 		 * one, prohibit requesting recovery, allow the raid
3134 		 * set to run and store superblocks during resume.
3135 		 */
3136 		r = rs_check_takeover(rs);
3137 		if (r)
3138 			goto bad;
3139 
3140 		r = rs_setup_takeover(rs);
3141 		if (r)
3142 			goto bad;
3143 
3144 		set_bit(RT_FLAG_UPDATE_SBS, &rs->runtime_flags);
3145 		/* Takeover ain't recovery, so disable recovery */
3146 		rs_setup_recovery(rs, MaxSector);
3147 		rs_set_new(rs);
3148 	} else if (rs_reshape_requested(rs)) {
3149 		/* Only request grow on raid set size extensions, not on reshapes. */
3150 		clear_bit(RT_FLAG_RS_GROW, &rs->runtime_flags);
3151 
3152 		/*
3153 		 * No need to check for 'ongoing' takeover here, because takeover
3154 		 * is an instant operation as oposed to an ongoing reshape.
3155 		 */
3156 
3157 		/* We can't reshape a journaled raid4/5/6 */
3158 		if (test_bit(__CTR_FLAG_JOURNAL_DEV, &rs->ctr_flags)) {
3159 			ti->error = "Can't reshape a journaled raid4/5/6 set";
3160 			r = -EPERM;
3161 			goto bad;
3162 		}
3163 
3164 		/* Out-of-place space has to be available to allow for a reshape unless raid1! */
3165 		if (reshape_sectors || rs_is_raid1(rs)) {
3166 			/*
3167 			  * We can only prepare for a reshape here, because the
3168 			  * raid set needs to run to provide the repective reshape
3169 			  * check functions via its MD personality instance.
3170 			  *
3171 			  * So do the reshape check after md_run() succeeded.
3172 			  */
3173 			r = rs_prepare_reshape(rs);
3174 			if (r)
3175 				goto bad;
3176 
3177 			/* Reshaping ain't recovery, so disable recovery */
3178 			rs_setup_recovery(rs, MaxSector);
3179 		}
3180 		rs_set_cur(rs);
3181 	} else {
3182 size_check:
3183 		/* May not set recovery when a device rebuild is requested */
3184 		if (test_bit(__CTR_FLAG_REBUILD, &rs->ctr_flags)) {
3185 			clear_bit(RT_FLAG_RS_GROW, &rs->runtime_flags);
3186 			set_bit(RT_FLAG_UPDATE_SBS, &rs->runtime_flags);
3187 			rs_setup_recovery(rs, MaxSector);
3188 		} else if (test_bit(RT_FLAG_RS_GROW, &rs->runtime_flags)) {
3189 			/*
3190 			 * Set raid set to current size, i.e. size as of
3191 			 * superblocks to grow to larger size in preresume.
3192 			 */
3193 			r = rs_set_dev_and_array_sectors(rs, sb_array_sectors, false);
3194 			if (r)
3195 				goto bad;
3196 
3197 			rs_setup_recovery(rs, rs->md.recovery_cp < rs->md.dev_sectors ? rs->md.recovery_cp : rs->md.dev_sectors);
3198 		} else {
3199 			/* This is no size change or it is shrinking, update size and record in superblocks */
3200 			r = rs_set_dev_and_array_sectors(rs, rs->ti->len, false);
3201 			if (r)
3202 				goto bad;
3203 
3204 			if (sb_array_sectors > rs->array_sectors)
3205 				set_bit(RT_FLAG_UPDATE_SBS, &rs->runtime_flags);
3206 		}
3207 		rs_set_cur(rs);
3208 	}
3209 
3210 	/* If constructor requested it, change data and new_data offsets */
3211 	r = rs_adjust_data_offsets(rs);
3212 	if (r)
3213 		goto bad;
3214 
3215 	/* Start raid set read-only and assumed clean to change in raid_resume() */
3216 	rs->md.ro = 1;
3217 	rs->md.in_sync = 1;
3218 
3219 	/* Keep array frozen */
3220 	set_bit(MD_RECOVERY_FROZEN, &rs->md.recovery);
3221 
3222 	/* Has to be held on running the array */
3223 	mddev_lock_nointr(&rs->md);
3224 	r = md_run(&rs->md);
3225 	rs->md.in_sync = 0; /* Assume already marked dirty */
3226 	if (r) {
3227 		ti->error = "Failed to run raid array";
3228 		mddev_unlock(&rs->md);
3229 		goto bad;
3230 	}
3231 
3232 	r = md_start(&rs->md);
3233 
3234 	if (r) {
3235 		ti->error = "Failed to start raid array";
3236 		mddev_unlock(&rs->md);
3237 		goto bad_md_start;
3238 	}
3239 
3240 	/* If raid4/5/6 journal mode explicitly requested (only possible with journal dev) -> set it */
3241 	if (test_bit(__CTR_FLAG_JOURNAL_MODE, &rs->ctr_flags)) {
3242 		r = r5c_journal_mode_set(&rs->md, rs->journal_dev.mode);
3243 		if (r) {
3244 			ti->error = "Failed to set raid4/5/6 journal mode";
3245 			mddev_unlock(&rs->md);
3246 			goto bad_journal_mode_set;
3247 		}
3248 	}
3249 
3250 	mddev_suspend(&rs->md);
3251 	set_bit(RT_FLAG_RS_SUSPENDED, &rs->runtime_flags);
3252 
3253 	/* Try to adjust the raid4/5/6 stripe cache size to the stripe size */
3254 	if (rs_is_raid456(rs)) {
3255 		r = rs_set_raid456_stripe_cache(rs);
3256 		if (r)
3257 			goto bad_stripe_cache;
3258 	}
3259 
3260 	/* Now do an early reshape check */
3261 	if (test_bit(RT_FLAG_RESHAPE_RS, &rs->runtime_flags)) {
3262 		r = rs_check_reshape(rs);
3263 		if (r)
3264 			goto bad_check_reshape;
3265 
3266 		/* Restore new, ctr requested layout to perform check */
3267 		rs_config_restore(rs, &rs_layout);
3268 
3269 		if (rs->md.pers->start_reshape) {
3270 			r = rs->md.pers->check_reshape(&rs->md);
3271 			if (r) {
3272 				ti->error = "Reshape check failed";
3273 				goto bad_check_reshape;
3274 			}
3275 		}
3276 	}
3277 
3278 	/* Disable/enable discard support on raid set. */
3279 	configure_discard_support(rs);
3280 
3281 	mddev_unlock(&rs->md);
3282 	return 0;
3283 
3284 bad_md_start:
3285 bad_journal_mode_set:
3286 bad_stripe_cache:
3287 bad_check_reshape:
3288 	md_stop(&rs->md);
3289 bad:
3290 	raid_set_free(rs);
3291 
3292 	return r;
3293 }
3294 
3295 static void raid_dtr(struct dm_target *ti)
3296 {
3297 	struct raid_set *rs = ti->private;
3298 
3299 	md_stop(&rs->md);
3300 	raid_set_free(rs);
3301 }
3302 
3303 static int raid_map(struct dm_target *ti, struct bio *bio)
3304 {
3305 	struct raid_set *rs = ti->private;
3306 	struct mddev *mddev = &rs->md;
3307 
3308 	/*
3309 	 * If we're reshaping to add disk(s)), ti->len and
3310 	 * mddev->array_sectors will differ during the process
3311 	 * (ti->len > mddev->array_sectors), so we have to requeue
3312 	 * bios with addresses > mddev->array_sectors here or
3313 	 * there will occur accesses past EOD of the component
3314 	 * data images thus erroring the raid set.
3315 	 */
3316 	if (unlikely(bio_end_sector(bio) > mddev->array_sectors))
3317 		return DM_MAPIO_REQUEUE;
3318 
3319 	md_handle_request(mddev, bio);
3320 
3321 	return DM_MAPIO_SUBMITTED;
3322 }
3323 
3324 /* Return sync state string for @state */
3325 enum sync_state { st_frozen, st_reshape, st_resync, st_check, st_repair, st_recover, st_idle };
3326 static const char *sync_str(enum sync_state state)
3327 {
3328 	/* Has to be in above sync_state order! */
3329 	static const char *sync_strs[] = {
3330 		"frozen",
3331 		"reshape",
3332 		"resync",
3333 		"check",
3334 		"repair",
3335 		"recover",
3336 		"idle"
3337 	};
3338 
3339 	return __within_range(state, 0, ARRAY_SIZE(sync_strs) - 1) ? sync_strs[state] : "undef";
3340 };
3341 
3342 /* Return enum sync_state for @mddev derived from @recovery flags */
3343 static enum sync_state decipher_sync_action(struct mddev *mddev, unsigned long recovery)
3344 {
3345 	if (test_bit(MD_RECOVERY_FROZEN, &recovery))
3346 		return st_frozen;
3347 
3348 	/* The MD sync thread can be done with io or be interrupted but still be running */
3349 	if (!test_bit(MD_RECOVERY_DONE, &recovery) &&
3350 	    (test_bit(MD_RECOVERY_RUNNING, &recovery) ||
3351 	     (!mddev->ro && test_bit(MD_RECOVERY_NEEDED, &recovery)))) {
3352 		if (test_bit(MD_RECOVERY_RESHAPE, &recovery))
3353 			return st_reshape;
3354 
3355 		if (test_bit(MD_RECOVERY_SYNC, &recovery)) {
3356 			if (!test_bit(MD_RECOVERY_REQUESTED, &recovery))
3357 				return st_resync;
3358 			if (test_bit(MD_RECOVERY_CHECK, &recovery))
3359 				return st_check;
3360 			return st_repair;
3361 		}
3362 
3363 		if (test_bit(MD_RECOVERY_RECOVER, &recovery))
3364 			return st_recover;
3365 
3366 		if (mddev->reshape_position != MaxSector)
3367 			return st_reshape;
3368 	}
3369 
3370 	return st_idle;
3371 }
3372 
3373 /*
3374  * Return status string for @rdev
3375  *
3376  * Status characters:
3377  *
3378  *  'D' = Dead/Failed raid set component or raid4/5/6 journal device
3379  *  'a' = Alive but not in-sync raid set component _or_ alive raid4/5/6 'write_back' journal device
3380  *  'A' = Alive and in-sync raid set component _or_ alive raid4/5/6 'write_through' journal device
3381  *  '-' = Non-existing device (i.e. uspace passed '- -' into the ctr)
3382  */
3383 static const char *__raid_dev_status(struct raid_set *rs, struct md_rdev *rdev)
3384 {
3385 	if (!rdev->bdev)
3386 		return "-";
3387 	else if (test_bit(Faulty, &rdev->flags))
3388 		return "D";
3389 	else if (test_bit(Journal, &rdev->flags))
3390 		return (rs->journal_dev.mode == R5C_JOURNAL_MODE_WRITE_THROUGH) ? "A" : "a";
3391 	else if (test_bit(RT_FLAG_RS_RESYNCING, &rs->runtime_flags) ||
3392 		 (!test_bit(RT_FLAG_RS_IN_SYNC, &rs->runtime_flags) &&
3393 		  !test_bit(In_sync, &rdev->flags)))
3394 		return "a";
3395 	else
3396 		return "A";
3397 }
3398 
3399 /* Helper to return resync/reshape progress for @rs and runtime flags for raid set in sync / resynching */
3400 static sector_t rs_get_progress(struct raid_set *rs, unsigned long recovery,
3401 				enum sync_state state, sector_t resync_max_sectors)
3402 {
3403 	sector_t r;
3404 	struct mddev *mddev = &rs->md;
3405 
3406 	clear_bit(RT_FLAG_RS_IN_SYNC, &rs->runtime_flags);
3407 	clear_bit(RT_FLAG_RS_RESYNCING, &rs->runtime_flags);
3408 
3409 	if (rs_is_raid0(rs)) {
3410 		r = resync_max_sectors;
3411 		set_bit(RT_FLAG_RS_IN_SYNC, &rs->runtime_flags);
3412 
3413 	} else {
3414 		if (state == st_idle && !test_bit(MD_RECOVERY_INTR, &recovery))
3415 			r = mddev->recovery_cp;
3416 		else
3417 			r = mddev->curr_resync_completed;
3418 
3419 		if (state == st_idle && r >= resync_max_sectors) {
3420 			/*
3421 			 * Sync complete.
3422 			 */
3423 			/* In case we have finished recovering, the array is in sync. */
3424 			if (test_bit(MD_RECOVERY_RECOVER, &recovery))
3425 				set_bit(RT_FLAG_RS_IN_SYNC, &rs->runtime_flags);
3426 
3427 		} else if (state == st_recover)
3428 			/*
3429 			 * In case we are recovering, the array is not in sync
3430 			 * and health chars should show the recovering legs.
3431 			 *
3432 			 * Already retrieved recovery offset from curr_resync_completed above.
3433 			 */
3434 			;
3435 
3436 		else if (state == st_resync || state == st_reshape)
3437 			/*
3438 			 * If "resync/reshape" is occurring, the raid set
3439 			 * is or may be out of sync hence the health
3440 			 * characters shall be 'a'.
3441 			 */
3442 			set_bit(RT_FLAG_RS_RESYNCING, &rs->runtime_flags);
3443 
3444 		else if (state == st_check || state == st_repair)
3445 			/*
3446 			 * If "check" or "repair" is occurring, the raid set has
3447 			 * undergone an initial sync and the health characters
3448 			 * should not be 'a' anymore.
3449 			 */
3450 			set_bit(RT_FLAG_RS_IN_SYNC, &rs->runtime_flags);
3451 
3452 		else if (test_bit(MD_RECOVERY_NEEDED, &recovery))
3453 			/*
3454 			 * We are idle and recovery is needed, prevent 'A' chars race
3455 			 * caused by components still set to in-sync by constructor.
3456 			 */
3457 			set_bit(RT_FLAG_RS_RESYNCING, &rs->runtime_flags);
3458 
3459 		else {
3460 			/*
3461 			 * We are idle and the raid set may be doing an initial
3462 			 * sync, or it may be rebuilding individual components.
3463 			 * If all the devices are In_sync, then it is the raid set
3464 			 * that is being initialized.
3465 			 */
3466 			struct md_rdev *rdev;
3467 
3468 			set_bit(RT_FLAG_RS_IN_SYNC, &rs->runtime_flags);
3469 			rdev_for_each(rdev, mddev)
3470 				if (!test_bit(Journal, &rdev->flags) &&
3471 				    !test_bit(In_sync, &rdev->flags)) {
3472 					clear_bit(RT_FLAG_RS_IN_SYNC, &rs->runtime_flags);
3473 					break;
3474 				}
3475 		}
3476 	}
3477 
3478 	return min(r, resync_max_sectors);
3479 }
3480 
3481 /* Helper to return @dev name or "-" if !@dev */
3482 static const char *__get_dev_name(struct dm_dev *dev)
3483 {
3484 	return dev ? dev->name : "-";
3485 }
3486 
3487 static void raid_status(struct dm_target *ti, status_type_t type,
3488 			unsigned int status_flags, char *result, unsigned int maxlen)
3489 {
3490 	struct raid_set *rs = ti->private;
3491 	struct mddev *mddev = &rs->md;
3492 	struct r5conf *conf = mddev->private;
3493 	int i, max_nr_stripes = conf ? conf->max_nr_stripes : 0;
3494 	unsigned long recovery;
3495 	unsigned int raid_param_cnt = 1; /* at least 1 for chunksize */
3496 	unsigned int sz = 0;
3497 	unsigned int rebuild_writemostly_count = 0;
3498 	sector_t progress, resync_max_sectors, resync_mismatches;
3499 	enum sync_state state;
3500 	struct raid_type *rt;
3501 
3502 	switch (type) {
3503 	case STATUSTYPE_INFO:
3504 		/* *Should* always succeed */
3505 		rt = get_raid_type_by_ll(mddev->new_level, mddev->new_layout);
3506 		if (!rt)
3507 			return;
3508 
3509 		DMEMIT("%s %d ", rt->name, mddev->raid_disks);
3510 
3511 		/* Access most recent mddev properties for status output */
3512 		smp_rmb();
3513 		/* Get sensible max sectors even if raid set not yet started */
3514 		resync_max_sectors = test_bit(RT_FLAG_RS_PRERESUMED, &rs->runtime_flags) ?
3515 				      mddev->resync_max_sectors : mddev->dev_sectors;
3516 		recovery = rs->md.recovery;
3517 		state = decipher_sync_action(mddev, recovery);
3518 		progress = rs_get_progress(rs, recovery, state, resync_max_sectors);
3519 		resync_mismatches = (mddev->last_sync_action && !strcasecmp(mddev->last_sync_action, "check")) ?
3520 				    atomic64_read(&mddev->resync_mismatches) : 0;
3521 
3522 		/* HM FIXME: do we want another state char for raid0? It shows 'D'/'A'/'-' now */
3523 		for (i = 0; i < rs->raid_disks; i++)
3524 			DMEMIT(__raid_dev_status(rs, &rs->dev[i].rdev));
3525 
3526 		/*
3527 		 * In-sync/Reshape ratio:
3528 		 *  The in-sync ratio shows the progress of:
3529 		 *   - Initializing the raid set
3530 		 *   - Rebuilding a subset of devices of the raid set
3531 		 *  The user can distinguish between the two by referring
3532 		 *  to the status characters.
3533 		 *
3534 		 *  The reshape ratio shows the progress of
3535 		 *  changing the raid layout or the number of
3536 		 *  disks of a raid set
3537 		 */
3538 		DMEMIT(" %llu/%llu", (unsigned long long) progress,
3539 				     (unsigned long long) resync_max_sectors);
3540 
3541 		/*
3542 		 * v1.5.0+:
3543 		 *
3544 		 * Sync action:
3545 		 *   See Documentation/admin-guide/device-mapper/dm-raid.rst for
3546 		 *   information on each of these states.
3547 		 */
3548 		DMEMIT(" %s", sync_str(state));
3549 
3550 		/*
3551 		 * v1.5.0+:
3552 		 *
3553 		 * resync_mismatches/mismatch_cnt
3554 		 *   This field shows the number of discrepancies found when
3555 		 *   performing a "check" of the raid set.
3556 		 */
3557 		DMEMIT(" %llu", (unsigned long long) resync_mismatches);
3558 
3559 		/*
3560 		 * v1.9.0+:
3561 		 *
3562 		 * data_offset (needed for out of space reshaping)
3563 		 *   This field shows the data offset into the data
3564 		 *   image LV where the first stripes data starts.
3565 		 *
3566 		 * We keep data_offset equal on all raid disks of the set,
3567 		 * so retrieving it from the first raid disk is sufficient.
3568 		 */
3569 		DMEMIT(" %llu", (unsigned long long) rs->dev[0].rdev.data_offset);
3570 
3571 		/*
3572 		 * v1.10.0+:
3573 		 */
3574 		DMEMIT(" %s", test_bit(__CTR_FLAG_JOURNAL_DEV, &rs->ctr_flags) ?
3575 			      __raid_dev_status(rs, &rs->journal_dev.rdev) : "-");
3576 		break;
3577 
3578 	case STATUSTYPE_TABLE:
3579 		/* Report the table line string you would use to construct this raid set */
3580 
3581 		/*
3582 		 * Count any rebuild or writemostly argument pairs and subtract the
3583 		 * hweight count being added below of any rebuild and writemostly ctr flags.
3584 		 */
3585 		for (i = 0; i < rs->raid_disks; i++) {
3586 			rebuild_writemostly_count += (test_bit(i, (void *) rs->rebuild_disks) ? 2 : 0) +
3587 						     (test_bit(WriteMostly, &rs->dev[i].rdev.flags) ? 2 : 0);
3588 		}
3589 		rebuild_writemostly_count -= (test_bit(__CTR_FLAG_REBUILD, &rs->ctr_flags) ? 2 : 0) +
3590 					     (test_bit(__CTR_FLAG_WRITE_MOSTLY, &rs->ctr_flags) ? 2 : 0);
3591 		/* Calculate raid parameter count based on ^ rebuild/writemostly argument counts and ctr flags set. */
3592 		raid_param_cnt += rebuild_writemostly_count +
3593 				  hweight32(rs->ctr_flags & CTR_FLAG_OPTIONS_NO_ARGS) +
3594 				  hweight32(rs->ctr_flags & CTR_FLAG_OPTIONS_ONE_ARG) * 2;
3595 		/* Emit table line */
3596 		/* This has to be in the documented order for userspace! */
3597 		DMEMIT("%s %u %u", rs->raid_type->name, raid_param_cnt, mddev->new_chunk_sectors);
3598 		if (test_bit(__CTR_FLAG_SYNC, &rs->ctr_flags))
3599 			DMEMIT(" %s", dm_raid_arg_name_by_flag(CTR_FLAG_SYNC));
3600 		if (test_bit(__CTR_FLAG_NOSYNC, &rs->ctr_flags))
3601 			DMEMIT(" %s", dm_raid_arg_name_by_flag(CTR_FLAG_NOSYNC));
3602 		if (test_bit(__CTR_FLAG_REBUILD, &rs->ctr_flags))
3603 			for (i = 0; i < rs->raid_disks; i++)
3604 				if (test_bit(i, (void *) rs->rebuild_disks))
3605 					DMEMIT(" %s %u", dm_raid_arg_name_by_flag(CTR_FLAG_REBUILD), i);
3606 		if (test_bit(__CTR_FLAG_DAEMON_SLEEP, &rs->ctr_flags))
3607 			DMEMIT(" %s %lu", dm_raid_arg_name_by_flag(CTR_FLAG_DAEMON_SLEEP),
3608 					  mddev->bitmap_info.daemon_sleep);
3609 		if (test_bit(__CTR_FLAG_MIN_RECOVERY_RATE, &rs->ctr_flags))
3610 			DMEMIT(" %s %d", dm_raid_arg_name_by_flag(CTR_FLAG_MIN_RECOVERY_RATE),
3611 					 mddev->sync_speed_min);
3612 		if (test_bit(__CTR_FLAG_MAX_RECOVERY_RATE, &rs->ctr_flags))
3613 			DMEMIT(" %s %d", dm_raid_arg_name_by_flag(CTR_FLAG_MAX_RECOVERY_RATE),
3614 					 mddev->sync_speed_max);
3615 		if (test_bit(__CTR_FLAG_WRITE_MOSTLY, &rs->ctr_flags))
3616 			for (i = 0; i < rs->raid_disks; i++)
3617 				if (test_bit(WriteMostly, &rs->dev[i].rdev.flags))
3618 					DMEMIT(" %s %d", dm_raid_arg_name_by_flag(CTR_FLAG_WRITE_MOSTLY),
3619 					       rs->dev[i].rdev.raid_disk);
3620 		if (test_bit(__CTR_FLAG_MAX_WRITE_BEHIND, &rs->ctr_flags))
3621 			DMEMIT(" %s %lu", dm_raid_arg_name_by_flag(CTR_FLAG_MAX_WRITE_BEHIND),
3622 					  mddev->bitmap_info.max_write_behind);
3623 		if (test_bit(__CTR_FLAG_STRIPE_CACHE, &rs->ctr_flags))
3624 			DMEMIT(" %s %d", dm_raid_arg_name_by_flag(CTR_FLAG_STRIPE_CACHE),
3625 					 max_nr_stripes);
3626 		if (test_bit(__CTR_FLAG_REGION_SIZE, &rs->ctr_flags))
3627 			DMEMIT(" %s %llu", dm_raid_arg_name_by_flag(CTR_FLAG_REGION_SIZE),
3628 					   (unsigned long long) to_sector(mddev->bitmap_info.chunksize));
3629 		if (test_bit(__CTR_FLAG_RAID10_COPIES, &rs->ctr_flags))
3630 			DMEMIT(" %s %d", dm_raid_arg_name_by_flag(CTR_FLAG_RAID10_COPIES),
3631 					 raid10_md_layout_to_copies(mddev->layout));
3632 		if (test_bit(__CTR_FLAG_RAID10_FORMAT, &rs->ctr_flags))
3633 			DMEMIT(" %s %s", dm_raid_arg_name_by_flag(CTR_FLAG_RAID10_FORMAT),
3634 					 raid10_md_layout_to_format(mddev->layout));
3635 		if (test_bit(__CTR_FLAG_DELTA_DISKS, &rs->ctr_flags))
3636 			DMEMIT(" %s %d", dm_raid_arg_name_by_flag(CTR_FLAG_DELTA_DISKS),
3637 					 max(rs->delta_disks, mddev->delta_disks));
3638 		if (test_bit(__CTR_FLAG_DATA_OFFSET, &rs->ctr_flags))
3639 			DMEMIT(" %s %llu", dm_raid_arg_name_by_flag(CTR_FLAG_DATA_OFFSET),
3640 					   (unsigned long long) rs->data_offset);
3641 		if (test_bit(__CTR_FLAG_JOURNAL_DEV, &rs->ctr_flags))
3642 			DMEMIT(" %s %s", dm_raid_arg_name_by_flag(CTR_FLAG_JOURNAL_DEV),
3643 					__get_dev_name(rs->journal_dev.dev));
3644 		if (test_bit(__CTR_FLAG_JOURNAL_MODE, &rs->ctr_flags))
3645 			DMEMIT(" %s %s", dm_raid_arg_name_by_flag(CTR_FLAG_JOURNAL_MODE),
3646 					 md_journal_mode_to_dm_raid(rs->journal_dev.mode));
3647 		DMEMIT(" %d", rs->raid_disks);
3648 		for (i = 0; i < rs->raid_disks; i++)
3649 			DMEMIT(" %s %s", __get_dev_name(rs->dev[i].meta_dev),
3650 					 __get_dev_name(rs->dev[i].data_dev));
3651 	}
3652 }
3653 
3654 static int raid_message(struct dm_target *ti, unsigned int argc, char **argv,
3655 			char *result, unsigned maxlen)
3656 {
3657 	struct raid_set *rs = ti->private;
3658 	struct mddev *mddev = &rs->md;
3659 
3660 	if (!mddev->pers || !mddev->pers->sync_request)
3661 		return -EINVAL;
3662 
3663 	if (!strcasecmp(argv[0], "frozen"))
3664 		set_bit(MD_RECOVERY_FROZEN, &mddev->recovery);
3665 	else
3666 		clear_bit(MD_RECOVERY_FROZEN, &mddev->recovery);
3667 
3668 	if (!strcasecmp(argv[0], "idle") || !strcasecmp(argv[0], "frozen")) {
3669 		if (mddev->sync_thread) {
3670 			set_bit(MD_RECOVERY_INTR, &mddev->recovery);
3671 			md_reap_sync_thread(mddev);
3672 		}
3673 	} else if (decipher_sync_action(mddev, mddev->recovery) != st_idle)
3674 		return -EBUSY;
3675 	else if (!strcasecmp(argv[0], "resync"))
3676 		; /* MD_RECOVERY_NEEDED set below */
3677 	else if (!strcasecmp(argv[0], "recover"))
3678 		set_bit(MD_RECOVERY_RECOVER, &mddev->recovery);
3679 	else {
3680 		if (!strcasecmp(argv[0], "check")) {
3681 			set_bit(MD_RECOVERY_CHECK, &mddev->recovery);
3682 			set_bit(MD_RECOVERY_REQUESTED, &mddev->recovery);
3683 			set_bit(MD_RECOVERY_SYNC, &mddev->recovery);
3684 		} else if (!strcasecmp(argv[0], "repair")) {
3685 			set_bit(MD_RECOVERY_REQUESTED, &mddev->recovery);
3686 			set_bit(MD_RECOVERY_SYNC, &mddev->recovery);
3687 		} else
3688 			return -EINVAL;
3689 	}
3690 	if (mddev->ro == 2) {
3691 		/* A write to sync_action is enough to justify
3692 		 * canceling read-auto mode
3693 		 */
3694 		mddev->ro = 0;
3695 		if (!mddev->suspended && mddev->sync_thread)
3696 			md_wakeup_thread(mddev->sync_thread);
3697 	}
3698 	set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
3699 	if (!mddev->suspended && mddev->thread)
3700 		md_wakeup_thread(mddev->thread);
3701 
3702 	return 0;
3703 }
3704 
3705 static int raid_iterate_devices(struct dm_target *ti,
3706 				iterate_devices_callout_fn fn, void *data)
3707 {
3708 	struct raid_set *rs = ti->private;
3709 	unsigned int i;
3710 	int r = 0;
3711 
3712 	for (i = 0; !r && i < rs->md.raid_disks; i++)
3713 		if (rs->dev[i].data_dev)
3714 			r = fn(ti,
3715 				 rs->dev[i].data_dev,
3716 				 0, /* No offset on data devs */
3717 				 rs->md.dev_sectors,
3718 				 data);
3719 
3720 	return r;
3721 }
3722 
3723 static void raid_io_hints(struct dm_target *ti, struct queue_limits *limits)
3724 {
3725 	struct raid_set *rs = ti->private;
3726 	unsigned int chunk_size_bytes = to_bytes(rs->md.chunk_sectors);
3727 
3728 	blk_limits_io_min(limits, chunk_size_bytes);
3729 	blk_limits_io_opt(limits, chunk_size_bytes * mddev_data_stripes(rs));
3730 
3731 	/*
3732 	 * RAID0 and RAID10 personalities require bio splitting,
3733 	 * RAID1/4/5/6 don't and process large discard bios properly.
3734 	 */
3735 	if (rs_is_raid0(rs) || rs_is_raid10(rs)) {
3736 		limits->discard_granularity = chunk_size_bytes;
3737 		limits->max_discard_sectors = rs->md.chunk_sectors;
3738 	}
3739 }
3740 
3741 static void raid_postsuspend(struct dm_target *ti)
3742 {
3743 	struct raid_set *rs = ti->private;
3744 
3745 	if (!test_and_set_bit(RT_FLAG_RS_SUSPENDED, &rs->runtime_flags)) {
3746 		/* Writes have to be stopped before suspending to avoid deadlocks. */
3747 		if (!test_bit(MD_RECOVERY_FROZEN, &rs->md.recovery))
3748 			md_stop_writes(&rs->md);
3749 
3750 		mddev_lock_nointr(&rs->md);
3751 		mddev_suspend(&rs->md);
3752 		mddev_unlock(&rs->md);
3753 	}
3754 }
3755 
3756 static void attempt_restore_of_faulty_devices(struct raid_set *rs)
3757 {
3758 	int i;
3759 	uint64_t cleared_failed_devices[DISKS_ARRAY_ELEMS];
3760 	unsigned long flags;
3761 	bool cleared = false;
3762 	struct dm_raid_superblock *sb;
3763 	struct mddev *mddev = &rs->md;
3764 	struct md_rdev *r;
3765 
3766 	/* RAID personalities have to provide hot add/remove methods or we need to bail out. */
3767 	if (!mddev->pers || !mddev->pers->hot_add_disk || !mddev->pers->hot_remove_disk)
3768 		return;
3769 
3770 	memset(cleared_failed_devices, 0, sizeof(cleared_failed_devices));
3771 
3772 	for (i = 0; i < mddev->raid_disks; i++) {
3773 		r = &rs->dev[i].rdev;
3774 		/* HM FIXME: enhance journal device recovery processing */
3775 		if (test_bit(Journal, &r->flags))
3776 			continue;
3777 
3778 		if (test_bit(Faulty, &r->flags) &&
3779 		    r->meta_bdev && !read_disk_sb(r, r->sb_size, true)) {
3780 			DMINFO("Faulty %s device #%d has readable super block."
3781 			       "  Attempting to revive it.",
3782 			       rs->raid_type->name, i);
3783 
3784 			/*
3785 			 * Faulty bit may be set, but sometimes the array can
3786 			 * be suspended before the personalities can respond
3787 			 * by removing the device from the array (i.e. calling
3788 			 * 'hot_remove_disk').	If they haven't yet removed
3789 			 * the failed device, its 'raid_disk' number will be
3790 			 * '>= 0' - meaning we must call this function
3791 			 * ourselves.
3792 			 */
3793 			flags = r->flags;
3794 			clear_bit(In_sync, &r->flags); /* Mandatory for hot remove. */
3795 			if (r->raid_disk >= 0) {
3796 				if (mddev->pers->hot_remove_disk(mddev, r)) {
3797 					/* Failed to revive this device, try next */
3798 					r->flags = flags;
3799 					continue;
3800 				}
3801 			} else
3802 				r->raid_disk = r->saved_raid_disk = i;
3803 
3804 			clear_bit(Faulty, &r->flags);
3805 			clear_bit(WriteErrorSeen, &r->flags);
3806 
3807 			if (mddev->pers->hot_add_disk(mddev, r)) {
3808 				/* Failed to revive this device, try next */
3809 				r->raid_disk = r->saved_raid_disk = -1;
3810 				r->flags = flags;
3811 			} else {
3812 				clear_bit(In_sync, &r->flags);
3813 				r->recovery_offset = 0;
3814 				set_bit(i, (void *) cleared_failed_devices);
3815 				cleared = true;
3816 			}
3817 		}
3818 	}
3819 
3820 	/* If any failed devices could be cleared, update all sbs failed_devices bits */
3821 	if (cleared) {
3822 		uint64_t failed_devices[DISKS_ARRAY_ELEMS];
3823 
3824 		rdev_for_each(r, &rs->md) {
3825 			if (test_bit(Journal, &r->flags))
3826 				continue;
3827 
3828 			sb = page_address(r->sb_page);
3829 			sb_retrieve_failed_devices(sb, failed_devices);
3830 
3831 			for (i = 0; i < DISKS_ARRAY_ELEMS; i++)
3832 				failed_devices[i] &= ~cleared_failed_devices[i];
3833 
3834 			sb_update_failed_devices(sb, failed_devices);
3835 		}
3836 	}
3837 }
3838 
3839 static int __load_dirty_region_bitmap(struct raid_set *rs)
3840 {
3841 	int r = 0;
3842 
3843 	/* Try loading the bitmap unless "raid0", which does not have one */
3844 	if (!rs_is_raid0(rs) &&
3845 	    !test_and_set_bit(RT_FLAG_RS_BITMAP_LOADED, &rs->runtime_flags)) {
3846 		r = md_bitmap_load(&rs->md);
3847 		if (r)
3848 			DMERR("Failed to load bitmap");
3849 	}
3850 
3851 	return r;
3852 }
3853 
3854 /* Enforce updating all superblocks */
3855 static void rs_update_sbs(struct raid_set *rs)
3856 {
3857 	struct mddev *mddev = &rs->md;
3858 	int ro = mddev->ro;
3859 
3860 	set_bit(MD_SB_CHANGE_DEVS, &mddev->sb_flags);
3861 	mddev->ro = 0;
3862 	md_update_sb(mddev, 1);
3863 	mddev->ro = ro;
3864 }
3865 
3866 /*
3867  * Reshape changes raid algorithm of @rs to new one within personality
3868  * (e.g. raid6_zr -> raid6_nc), changes stripe size, adds/removes
3869  * disks from a raid set thus growing/shrinking it or resizes the set
3870  *
3871  * Call mddev_lock_nointr() before!
3872  */
3873 static int rs_start_reshape(struct raid_set *rs)
3874 {
3875 	int r;
3876 	struct mddev *mddev = &rs->md;
3877 	struct md_personality *pers = mddev->pers;
3878 
3879 	/* Don't allow the sync thread to work until the table gets reloaded. */
3880 	set_bit(MD_RECOVERY_WAIT, &mddev->recovery);
3881 
3882 	r = rs_setup_reshape(rs);
3883 	if (r)
3884 		return r;
3885 
3886 	/*
3887 	 * Check any reshape constraints enforced by the personalility
3888 	 *
3889 	 * May as well already kick the reshape off so that * pers->start_reshape() becomes optional.
3890 	 */
3891 	r = pers->check_reshape(mddev);
3892 	if (r) {
3893 		rs->ti->error = "pers->check_reshape() failed";
3894 		return r;
3895 	}
3896 
3897 	/*
3898 	 * Personality may not provide start reshape method in which
3899 	 * case check_reshape above has already covered everything
3900 	 */
3901 	if (pers->start_reshape) {
3902 		r = pers->start_reshape(mddev);
3903 		if (r) {
3904 			rs->ti->error = "pers->start_reshape() failed";
3905 			return r;
3906 		}
3907 	}
3908 
3909 	/*
3910 	 * Now reshape got set up, update superblocks to
3911 	 * reflect the fact so that a table reload will
3912 	 * access proper superblock content in the ctr.
3913 	 */
3914 	rs_update_sbs(rs);
3915 
3916 	return 0;
3917 }
3918 
3919 static int raid_preresume(struct dm_target *ti)
3920 {
3921 	int r;
3922 	struct raid_set *rs = ti->private;
3923 	struct mddev *mddev = &rs->md;
3924 
3925 	/* This is a resume after a suspend of the set -> it's already started. */
3926 	if (test_and_set_bit(RT_FLAG_RS_PRERESUMED, &rs->runtime_flags))
3927 		return 0;
3928 
3929 	/*
3930 	 * The superblocks need to be updated on disk if the
3931 	 * array is new or new devices got added (thus zeroed
3932 	 * out by userspace) or __load_dirty_region_bitmap
3933 	 * will overwrite them in core with old data or fail.
3934 	 */
3935 	if (test_bit(RT_FLAG_UPDATE_SBS, &rs->runtime_flags))
3936 		rs_update_sbs(rs);
3937 
3938 	/* Load the bitmap from disk unless raid0 */
3939 	r = __load_dirty_region_bitmap(rs);
3940 	if (r)
3941 		return r;
3942 
3943 	/* We are extending the raid set size, adjust mddev/md_rdev sizes and set capacity. */
3944 	if (test_bit(RT_FLAG_RS_GROW, &rs->runtime_flags)) {
3945 		mddev->array_sectors = rs->array_sectors;
3946 		mddev->dev_sectors = rs->dev_sectors;
3947 		rs_set_rdev_sectors(rs);
3948 		rs_set_capacity(rs);
3949 	}
3950 
3951 	/* Resize bitmap to adjust to changed region size (aka MD bitmap chunksize) or grown device size */
3952         if (test_bit(RT_FLAG_RS_BITMAP_LOADED, &rs->runtime_flags) && mddev->bitmap &&
3953 	    (test_bit(RT_FLAG_RS_GROW, &rs->runtime_flags) ||
3954 	     (rs->requested_bitmap_chunk_sectors &&
3955 	       mddev->bitmap_info.chunksize != to_bytes(rs->requested_bitmap_chunk_sectors)))) {
3956 		int chunksize = to_bytes(rs->requested_bitmap_chunk_sectors) ?: mddev->bitmap_info.chunksize;
3957 
3958 		r = md_bitmap_resize(mddev->bitmap, mddev->dev_sectors, chunksize, 0);
3959 		if (r)
3960 			DMERR("Failed to resize bitmap");
3961 	}
3962 
3963 	/* Check for any resize/reshape on @rs and adjust/initiate */
3964 	/* Be prepared for mddev_resume() in raid_resume() */
3965 	set_bit(MD_RECOVERY_FROZEN, &mddev->recovery);
3966 	if (mddev->recovery_cp && mddev->recovery_cp < MaxSector) {
3967 		set_bit(MD_RECOVERY_REQUESTED, &mddev->recovery);
3968 		mddev->resync_min = mddev->recovery_cp;
3969 		if (test_bit(RT_FLAG_RS_GROW, &rs->runtime_flags))
3970 			mddev->resync_max_sectors = mddev->dev_sectors;
3971 	}
3972 
3973 	/* Check for any reshape request unless new raid set */
3974 	if (test_bit(RT_FLAG_RESHAPE_RS, &rs->runtime_flags)) {
3975 		/* Initiate a reshape. */
3976 		rs_set_rdev_sectors(rs);
3977 		mddev_lock_nointr(mddev);
3978 		r = rs_start_reshape(rs);
3979 		mddev_unlock(mddev);
3980 		if (r)
3981 			DMWARN("Failed to check/start reshape, continuing without change");
3982 		r = 0;
3983 	}
3984 
3985 	return r;
3986 }
3987 
3988 static void raid_resume(struct dm_target *ti)
3989 {
3990 	struct raid_set *rs = ti->private;
3991 	struct mddev *mddev = &rs->md;
3992 
3993 	if (test_and_set_bit(RT_FLAG_RS_RESUMED, &rs->runtime_flags)) {
3994 		/*
3995 		 * A secondary resume while the device is active.
3996 		 * Take this opportunity to check whether any failed
3997 		 * devices are reachable again.
3998 		 */
3999 		attempt_restore_of_faulty_devices(rs);
4000 	}
4001 
4002 	if (test_and_clear_bit(RT_FLAG_RS_SUSPENDED, &rs->runtime_flags)) {
4003 		/* Only reduce raid set size before running a disk removing reshape. */
4004 		if (mddev->delta_disks < 0)
4005 			rs_set_capacity(rs);
4006 
4007 		mddev_lock_nointr(mddev);
4008 		clear_bit(MD_RECOVERY_FROZEN, &mddev->recovery);
4009 		mddev->ro = 0;
4010 		mddev->in_sync = 0;
4011 		mddev_resume(mddev);
4012 		mddev_unlock(mddev);
4013 	}
4014 }
4015 
4016 static struct target_type raid_target = {
4017 	.name = "raid",
4018 	.version = {1, 15, 1},
4019 	.module = THIS_MODULE,
4020 	.ctr = raid_ctr,
4021 	.dtr = raid_dtr,
4022 	.map = raid_map,
4023 	.status = raid_status,
4024 	.message = raid_message,
4025 	.iterate_devices = raid_iterate_devices,
4026 	.io_hints = raid_io_hints,
4027 	.postsuspend = raid_postsuspend,
4028 	.preresume = raid_preresume,
4029 	.resume = raid_resume,
4030 };
4031 
4032 static int __init dm_raid_init(void)
4033 {
4034 	DMINFO("Loading target version %u.%u.%u",
4035 	       raid_target.version[0],
4036 	       raid_target.version[1],
4037 	       raid_target.version[2]);
4038 	return dm_register_target(&raid_target);
4039 }
4040 
4041 static void __exit dm_raid_exit(void)
4042 {
4043 	dm_unregister_target(&raid_target);
4044 }
4045 
4046 module_init(dm_raid_init);
4047 module_exit(dm_raid_exit);
4048 
4049 module_param(devices_handle_discard_safely, bool, 0644);
4050 MODULE_PARM_DESC(devices_handle_discard_safely,
4051 		 "Set to Y if all devices in each array reliably return zeroes on reads from discarded regions");
4052 
4053 MODULE_DESCRIPTION(DM_NAME " raid0/1/10/4/5/6 target");
4054 MODULE_ALIAS("dm-raid0");
4055 MODULE_ALIAS("dm-raid1");
4056 MODULE_ALIAS("dm-raid10");
4057 MODULE_ALIAS("dm-raid4");
4058 MODULE_ALIAS("dm-raid5");
4059 MODULE_ALIAS("dm-raid6");
4060 MODULE_AUTHOR("Neil Brown <dm-devel@redhat.com>");
4061 MODULE_AUTHOR("Heinz Mauelshagen <dm-devel@redhat.com>");
4062 MODULE_LICENSE("GPL");
4063