xref: /openbmc/linux/drivers/md/dm-raid.c (revision bcd684aa)
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(gendisk, rs->md.array_sectors);
704 	revalidate_disk_size(gendisk, true);
705 }
706 
707 /*
708  * Set the mddev properties in @rs to the current
709  * ones retrieved from the freshest superblock
710  */
711 static void rs_set_cur(struct raid_set *rs)
712 {
713 	struct mddev *mddev = &rs->md;
714 
715 	mddev->new_level = mddev->level;
716 	mddev->new_layout = mddev->layout;
717 	mddev->new_chunk_sectors = mddev->chunk_sectors;
718 }
719 
720 /*
721  * Set the mddev properties in @rs to the new
722  * ones requested by the ctr
723  */
724 static void rs_set_new(struct raid_set *rs)
725 {
726 	struct mddev *mddev = &rs->md;
727 
728 	mddev->level = mddev->new_level;
729 	mddev->layout = mddev->new_layout;
730 	mddev->chunk_sectors = mddev->new_chunk_sectors;
731 	mddev->raid_disks = rs->raid_disks;
732 	mddev->delta_disks = 0;
733 }
734 
735 static struct raid_set *raid_set_alloc(struct dm_target *ti, struct raid_type *raid_type,
736 				       unsigned int raid_devs)
737 {
738 	unsigned int i;
739 	struct raid_set *rs;
740 
741 	if (raid_devs <= raid_type->parity_devs) {
742 		ti->error = "Insufficient number of devices";
743 		return ERR_PTR(-EINVAL);
744 	}
745 
746 	rs = kzalloc(struct_size(rs, dev, raid_devs), GFP_KERNEL);
747 	if (!rs) {
748 		ti->error = "Cannot allocate raid context";
749 		return ERR_PTR(-ENOMEM);
750 	}
751 
752 	mddev_init(&rs->md);
753 
754 	rs->raid_disks = raid_devs;
755 	rs->delta_disks = 0;
756 
757 	rs->ti = ti;
758 	rs->raid_type = raid_type;
759 	rs->stripe_cache_entries = 256;
760 	rs->md.raid_disks = raid_devs;
761 	rs->md.level = raid_type->level;
762 	rs->md.new_level = rs->md.level;
763 	rs->md.layout = raid_type->algorithm;
764 	rs->md.new_layout = rs->md.layout;
765 	rs->md.delta_disks = 0;
766 	rs->md.recovery_cp = MaxSector;
767 
768 	for (i = 0; i < raid_devs; i++)
769 		md_rdev_init(&rs->dev[i].rdev);
770 
771 	/*
772 	 * Remaining items to be initialized by further RAID params:
773 	 *  rs->md.persistent
774 	 *  rs->md.external
775 	 *  rs->md.chunk_sectors
776 	 *  rs->md.new_chunk_sectors
777 	 *  rs->md.dev_sectors
778 	 */
779 
780 	return rs;
781 }
782 
783 /* Free all @rs allocations */
784 static void raid_set_free(struct raid_set *rs)
785 {
786 	int i;
787 
788 	if (rs->journal_dev.dev) {
789 		md_rdev_clear(&rs->journal_dev.rdev);
790 		dm_put_device(rs->ti, rs->journal_dev.dev);
791 	}
792 
793 	for (i = 0; i < rs->raid_disks; i++) {
794 		if (rs->dev[i].meta_dev)
795 			dm_put_device(rs->ti, rs->dev[i].meta_dev);
796 		md_rdev_clear(&rs->dev[i].rdev);
797 		if (rs->dev[i].data_dev)
798 			dm_put_device(rs->ti, rs->dev[i].data_dev);
799 	}
800 
801 	kfree(rs);
802 }
803 
804 /*
805  * For every device we have two words
806  *  <meta_dev>: meta device name or '-' if missing
807  *  <data_dev>: data device name or '-' if missing
808  *
809  * The following are permitted:
810  *    - -
811  *    - <data_dev>
812  *    <meta_dev> <data_dev>
813  *
814  * The following is not allowed:
815  *    <meta_dev> -
816  *
817  * This code parses those words.  If there is a failure,
818  * the caller must use raid_set_free() to unwind the operations.
819  */
820 static int parse_dev_params(struct raid_set *rs, struct dm_arg_set *as)
821 {
822 	int i;
823 	int rebuild = 0;
824 	int metadata_available = 0;
825 	int r = 0;
826 	const char *arg;
827 
828 	/* Put off the number of raid devices argument to get to dev pairs */
829 	arg = dm_shift_arg(as);
830 	if (!arg)
831 		return -EINVAL;
832 
833 	for (i = 0; i < rs->raid_disks; i++) {
834 		rs->dev[i].rdev.raid_disk = i;
835 
836 		rs->dev[i].meta_dev = NULL;
837 		rs->dev[i].data_dev = NULL;
838 
839 		/*
840 		 * There are no offsets initially.
841 		 * Out of place reshape will set them accordingly.
842 		 */
843 		rs->dev[i].rdev.data_offset = 0;
844 		rs->dev[i].rdev.new_data_offset = 0;
845 		rs->dev[i].rdev.mddev = &rs->md;
846 
847 		arg = dm_shift_arg(as);
848 		if (!arg)
849 			return -EINVAL;
850 
851 		if (strcmp(arg, "-")) {
852 			r = dm_get_device(rs->ti, arg, dm_table_get_mode(rs->ti->table),
853 					  &rs->dev[i].meta_dev);
854 			if (r) {
855 				rs->ti->error = "RAID metadata device lookup failure";
856 				return r;
857 			}
858 
859 			rs->dev[i].rdev.sb_page = alloc_page(GFP_KERNEL);
860 			if (!rs->dev[i].rdev.sb_page) {
861 				rs->ti->error = "Failed to allocate superblock page";
862 				return -ENOMEM;
863 			}
864 		}
865 
866 		arg = dm_shift_arg(as);
867 		if (!arg)
868 			return -EINVAL;
869 
870 		if (!strcmp(arg, "-")) {
871 			if (!test_bit(In_sync, &rs->dev[i].rdev.flags) &&
872 			    (!rs->dev[i].rdev.recovery_offset)) {
873 				rs->ti->error = "Drive designated for rebuild not specified";
874 				return -EINVAL;
875 			}
876 
877 			if (rs->dev[i].meta_dev) {
878 				rs->ti->error = "No data device supplied with metadata device";
879 				return -EINVAL;
880 			}
881 
882 			continue;
883 		}
884 
885 		r = dm_get_device(rs->ti, arg, dm_table_get_mode(rs->ti->table),
886 				  &rs->dev[i].data_dev);
887 		if (r) {
888 			rs->ti->error = "RAID device lookup failure";
889 			return r;
890 		}
891 
892 		if (rs->dev[i].meta_dev) {
893 			metadata_available = 1;
894 			rs->dev[i].rdev.meta_bdev = rs->dev[i].meta_dev->bdev;
895 		}
896 		rs->dev[i].rdev.bdev = rs->dev[i].data_dev->bdev;
897 		list_add_tail(&rs->dev[i].rdev.same_set, &rs->md.disks);
898 		if (!test_bit(In_sync, &rs->dev[i].rdev.flags))
899 			rebuild++;
900 	}
901 
902 	if (rs->journal_dev.dev)
903 		list_add_tail(&rs->journal_dev.rdev.same_set, &rs->md.disks);
904 
905 	if (metadata_available) {
906 		rs->md.external = 0;
907 		rs->md.persistent = 1;
908 		rs->md.major_version = 2;
909 	} else if (rebuild && !rs->md.recovery_cp) {
910 		/*
911 		 * Without metadata, we will not be able to tell if the array
912 		 * is in-sync or not - we must assume it is not.  Therefore,
913 		 * it is impossible to rebuild a drive.
914 		 *
915 		 * Even if there is metadata, the on-disk information may
916 		 * indicate that the array is not in-sync and it will then
917 		 * fail at that time.
918 		 *
919 		 * User could specify 'nosync' option if desperate.
920 		 */
921 		rs->ti->error = "Unable to rebuild drive while array is not in-sync";
922 		return -EINVAL;
923 	}
924 
925 	return 0;
926 }
927 
928 /*
929  * validate_region_size
930  * @rs
931  * @region_size:  region size in sectors.  If 0, pick a size (4MiB default).
932  *
933  * Set rs->md.bitmap_info.chunksize (which really refers to 'region size').
934  * Ensure that (ti->len/region_size < 2^21) - required by MD bitmap.
935  *
936  * Returns: 0 on success, -EINVAL on failure.
937  */
938 static int validate_region_size(struct raid_set *rs, unsigned long region_size)
939 {
940 	unsigned long min_region_size = rs->ti->len / (1 << 21);
941 
942 	if (rs_is_raid0(rs))
943 		return 0;
944 
945 	if (!region_size) {
946 		/*
947 		 * Choose a reasonable default.	 All figures in sectors.
948 		 */
949 		if (min_region_size > (1 << 13)) {
950 			/* If not a power of 2, make it the next power of 2 */
951 			region_size = roundup_pow_of_two(min_region_size);
952 			DMINFO("Choosing default region size of %lu sectors",
953 			       region_size);
954 		} else {
955 			DMINFO("Choosing default region size of 4MiB");
956 			region_size = 1 << 13; /* sectors */
957 		}
958 	} else {
959 		/*
960 		 * Validate user-supplied value.
961 		 */
962 		if (region_size > rs->ti->len) {
963 			rs->ti->error = "Supplied region size is too large";
964 			return -EINVAL;
965 		}
966 
967 		if (region_size < min_region_size) {
968 			DMERR("Supplied region_size (%lu sectors) below minimum (%lu)",
969 			      region_size, min_region_size);
970 			rs->ti->error = "Supplied region size is too small";
971 			return -EINVAL;
972 		}
973 
974 		if (!is_power_of_2(region_size)) {
975 			rs->ti->error = "Region size is not a power of 2";
976 			return -EINVAL;
977 		}
978 
979 		if (region_size < rs->md.chunk_sectors) {
980 			rs->ti->error = "Region size is smaller than the chunk size";
981 			return -EINVAL;
982 		}
983 	}
984 
985 	/*
986 	 * Convert sectors to bytes.
987 	 */
988 	rs->md.bitmap_info.chunksize = to_bytes(region_size);
989 
990 	return 0;
991 }
992 
993 /*
994  * validate_raid_redundancy
995  * @rs
996  *
997  * Determine if there are enough devices in the array that haven't
998  * failed (or are being rebuilt) to form a usable array.
999  *
1000  * Returns: 0 on success, -EINVAL on failure.
1001  */
1002 static int validate_raid_redundancy(struct raid_set *rs)
1003 {
1004 	unsigned int i, rebuild_cnt = 0;
1005 	unsigned int rebuilds_per_group = 0, copies;
1006 	unsigned int group_size, last_group_start;
1007 
1008 	for (i = 0; i < rs->md.raid_disks; i++)
1009 		if (!test_bit(In_sync, &rs->dev[i].rdev.flags) ||
1010 		    !rs->dev[i].rdev.sb_page)
1011 			rebuild_cnt++;
1012 
1013 	switch (rs->md.level) {
1014 	case 0:
1015 		break;
1016 	case 1:
1017 		if (rebuild_cnt >= rs->md.raid_disks)
1018 			goto too_many;
1019 		break;
1020 	case 4:
1021 	case 5:
1022 	case 6:
1023 		if (rebuild_cnt > rs->raid_type->parity_devs)
1024 			goto too_many;
1025 		break;
1026 	case 10:
1027 		copies = raid10_md_layout_to_copies(rs->md.new_layout);
1028 		if (copies < 2) {
1029 			DMERR("Bogus raid10 data copies < 2!");
1030 			return -EINVAL;
1031 		}
1032 
1033 		if (rebuild_cnt < copies)
1034 			break;
1035 
1036 		/*
1037 		 * It is possible to have a higher rebuild count for RAID10,
1038 		 * as long as the failed devices occur in different mirror
1039 		 * groups (i.e. different stripes).
1040 		 *
1041 		 * When checking "near" format, make sure no adjacent devices
1042 		 * have failed beyond what can be handled.  In addition to the
1043 		 * simple case where the number of devices is a multiple of the
1044 		 * number of copies, we must also handle cases where the number
1045 		 * of devices is not a multiple of the number of copies.
1046 		 * E.g.	   dev1 dev2 dev3 dev4 dev5
1047 		 *	    A	 A    B	   B	C
1048 		 *	    C	 D    D	   E	E
1049 		 */
1050 		if (__is_raid10_near(rs->md.new_layout)) {
1051 			for (i = 0; i < rs->md.raid_disks; i++) {
1052 				if (!(i % copies))
1053 					rebuilds_per_group = 0;
1054 				if ((!rs->dev[i].rdev.sb_page ||
1055 				    !test_bit(In_sync, &rs->dev[i].rdev.flags)) &&
1056 				    (++rebuilds_per_group >= copies))
1057 					goto too_many;
1058 			}
1059 			break;
1060 		}
1061 
1062 		/*
1063 		 * When checking "far" and "offset" formats, we need to ensure
1064 		 * that the device that holds its copy is not also dead or
1065 		 * being rebuilt.  (Note that "far" and "offset" formats only
1066 		 * support two copies right now.  These formats also only ever
1067 		 * use the 'use_far_sets' variant.)
1068 		 *
1069 		 * This check is somewhat complicated by the need to account
1070 		 * for arrays that are not a multiple of (far) copies.	This
1071 		 * results in the need to treat the last (potentially larger)
1072 		 * set differently.
1073 		 */
1074 		group_size = (rs->md.raid_disks / copies);
1075 		last_group_start = (rs->md.raid_disks / group_size) - 1;
1076 		last_group_start *= group_size;
1077 		for (i = 0; i < rs->md.raid_disks; i++) {
1078 			if (!(i % copies) && !(i > last_group_start))
1079 				rebuilds_per_group = 0;
1080 			if ((!rs->dev[i].rdev.sb_page ||
1081 			     !test_bit(In_sync, &rs->dev[i].rdev.flags)) &&
1082 			    (++rebuilds_per_group >= copies))
1083 					goto too_many;
1084 		}
1085 		break;
1086 	default:
1087 		if (rebuild_cnt)
1088 			return -EINVAL;
1089 	}
1090 
1091 	return 0;
1092 
1093 too_many:
1094 	return -EINVAL;
1095 }
1096 
1097 /*
1098  * Possible arguments are...
1099  *	<chunk_size> [optional_args]
1100  *
1101  * Argument definitions
1102  *    <chunk_size>			The number of sectors per disk that
1103  *					will form the "stripe"
1104  *    [[no]sync]			Force or prevent recovery of the
1105  *					entire array
1106  *    [rebuild <idx>]			Rebuild the drive indicated by the index
1107  *    [daemon_sleep <ms>]		Time between bitmap daemon work to
1108  *					clear bits
1109  *    [min_recovery_rate <kB/sec/disk>]	Throttle RAID initialization
1110  *    [max_recovery_rate <kB/sec/disk>]	Throttle RAID initialization
1111  *    [write_mostly <idx>]		Indicate a write mostly drive via index
1112  *    [max_write_behind <sectors>]	See '-write-behind=' (man mdadm)
1113  *    [stripe_cache <sectors>]		Stripe cache size for higher RAIDs
1114  *    [region_size <sectors>]		Defines granularity of bitmap
1115  *    [journal_dev <dev>]		raid4/5/6 journaling deviice
1116  *    					(i.e. write hole closing log)
1117  *
1118  * RAID10-only options:
1119  *    [raid10_copies <# copies>]	Number of copies.  (Default: 2)
1120  *    [raid10_format <near|far|offset>] Layout algorithm.  (Default: near)
1121  */
1122 static int parse_raid_params(struct raid_set *rs, struct dm_arg_set *as,
1123 			     unsigned int num_raid_params)
1124 {
1125 	int value, raid10_format = ALGORITHM_RAID10_DEFAULT;
1126 	unsigned int raid10_copies = 2;
1127 	unsigned int i, write_mostly = 0;
1128 	unsigned int region_size = 0;
1129 	sector_t max_io_len;
1130 	const char *arg, *key;
1131 	struct raid_dev *rd;
1132 	struct raid_type *rt = rs->raid_type;
1133 
1134 	arg = dm_shift_arg(as);
1135 	num_raid_params--; /* Account for chunk_size argument */
1136 
1137 	if (kstrtoint(arg, 10, &value) < 0) {
1138 		rs->ti->error = "Bad numerical argument given for chunk_size";
1139 		return -EINVAL;
1140 	}
1141 
1142 	/*
1143 	 * First, parse the in-order required arguments
1144 	 * "chunk_size" is the only argument of this type.
1145 	 */
1146 	if (rt_is_raid1(rt)) {
1147 		if (value)
1148 			DMERR("Ignoring chunk size parameter for RAID 1");
1149 		value = 0;
1150 	} else if (!is_power_of_2(value)) {
1151 		rs->ti->error = "Chunk size must be a power of 2";
1152 		return -EINVAL;
1153 	} else if (value < 8) {
1154 		rs->ti->error = "Chunk size value is too small";
1155 		return -EINVAL;
1156 	}
1157 
1158 	rs->md.new_chunk_sectors = rs->md.chunk_sectors = value;
1159 
1160 	/*
1161 	 * We set each individual device as In_sync with a completed
1162 	 * 'recovery_offset'.  If there has been a device failure or
1163 	 * replacement then one of the following cases applies:
1164 	 *
1165 	 *   1) User specifies 'rebuild'.
1166 	 *	- Device is reset when param is read.
1167 	 *   2) A new device is supplied.
1168 	 *	- No matching superblock found, resets device.
1169 	 *   3) Device failure was transient and returns on reload.
1170 	 *	- Failure noticed, resets device for bitmap replay.
1171 	 *   4) Device hadn't completed recovery after previous failure.
1172 	 *	- Superblock is read and overrides recovery_offset.
1173 	 *
1174 	 * What is found in the superblocks of the devices is always
1175 	 * authoritative, unless 'rebuild' or '[no]sync' was specified.
1176 	 */
1177 	for (i = 0; i < rs->raid_disks; i++) {
1178 		set_bit(In_sync, &rs->dev[i].rdev.flags);
1179 		rs->dev[i].rdev.recovery_offset = MaxSector;
1180 	}
1181 
1182 	/*
1183 	 * Second, parse the unordered optional arguments
1184 	 */
1185 	for (i = 0; i < num_raid_params; i++) {
1186 		key = dm_shift_arg(as);
1187 		if (!key) {
1188 			rs->ti->error = "Not enough raid parameters given";
1189 			return -EINVAL;
1190 		}
1191 
1192 		if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_NOSYNC))) {
1193 			if (test_and_set_bit(__CTR_FLAG_NOSYNC, &rs->ctr_flags)) {
1194 				rs->ti->error = "Only one 'nosync' argument allowed";
1195 				return -EINVAL;
1196 			}
1197 			continue;
1198 		}
1199 		if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_SYNC))) {
1200 			if (test_and_set_bit(__CTR_FLAG_SYNC, &rs->ctr_flags)) {
1201 				rs->ti->error = "Only one 'sync' argument allowed";
1202 				return -EINVAL;
1203 			}
1204 			continue;
1205 		}
1206 		if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_RAID10_USE_NEAR_SETS))) {
1207 			if (test_and_set_bit(__CTR_FLAG_RAID10_USE_NEAR_SETS, &rs->ctr_flags)) {
1208 				rs->ti->error = "Only one 'raid10_use_new_sets' argument allowed";
1209 				return -EINVAL;
1210 			}
1211 			continue;
1212 		}
1213 
1214 		arg = dm_shift_arg(as);
1215 		i++; /* Account for the argument pairs */
1216 		if (!arg) {
1217 			rs->ti->error = "Wrong number of raid parameters given";
1218 			return -EINVAL;
1219 		}
1220 
1221 		/*
1222 		 * Parameters that take a string value are checked here.
1223 		 */
1224 		/* "raid10_format {near|offset|far} */
1225 		if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_RAID10_FORMAT))) {
1226 			if (test_and_set_bit(__CTR_FLAG_RAID10_FORMAT, &rs->ctr_flags)) {
1227 				rs->ti->error = "Only one 'raid10_format' argument pair allowed";
1228 				return -EINVAL;
1229 			}
1230 			if (!rt_is_raid10(rt)) {
1231 				rs->ti->error = "'raid10_format' is an invalid parameter for this RAID type";
1232 				return -EINVAL;
1233 			}
1234 			raid10_format = raid10_name_to_format(arg);
1235 			if (raid10_format < 0) {
1236 				rs->ti->error = "Invalid 'raid10_format' value given";
1237 				return raid10_format;
1238 			}
1239 			continue;
1240 		}
1241 
1242 		/* "journal_dev <dev>" */
1243 		if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_JOURNAL_DEV))) {
1244 			int r;
1245 			struct md_rdev *jdev;
1246 
1247 			if (test_and_set_bit(__CTR_FLAG_JOURNAL_DEV, &rs->ctr_flags)) {
1248 				rs->ti->error = "Only one raid4/5/6 set journaling device allowed";
1249 				return -EINVAL;
1250 			}
1251 			if (!rt_is_raid456(rt)) {
1252 				rs->ti->error = "'journal_dev' is an invalid parameter for this RAID type";
1253 				return -EINVAL;
1254 			}
1255 			r = dm_get_device(rs->ti, arg, dm_table_get_mode(rs->ti->table),
1256 					  &rs->journal_dev.dev);
1257 			if (r) {
1258 				rs->ti->error = "raid4/5/6 journal device lookup failure";
1259 				return r;
1260 			}
1261 			jdev = &rs->journal_dev.rdev;
1262 			md_rdev_init(jdev);
1263 			jdev->mddev = &rs->md;
1264 			jdev->bdev = rs->journal_dev.dev->bdev;
1265 			jdev->sectors = to_sector(i_size_read(jdev->bdev->bd_inode));
1266 			if (jdev->sectors < MIN_RAID456_JOURNAL_SPACE) {
1267 				rs->ti->error = "No space for raid4/5/6 journal";
1268 				return -ENOSPC;
1269 			}
1270 			rs->journal_dev.mode = R5C_JOURNAL_MODE_WRITE_THROUGH;
1271 			set_bit(Journal, &jdev->flags);
1272 			continue;
1273 		}
1274 
1275 		/* "journal_mode <mode>" ("journal_dev" mandatory!) */
1276 		if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_JOURNAL_MODE))) {
1277 			int r;
1278 
1279 			if (!test_bit(__CTR_FLAG_JOURNAL_DEV, &rs->ctr_flags)) {
1280 				rs->ti->error = "raid4/5/6 'journal_mode' is invalid without 'journal_dev'";
1281 				return -EINVAL;
1282 			}
1283 			if (test_and_set_bit(__CTR_FLAG_JOURNAL_MODE, &rs->ctr_flags)) {
1284 				rs->ti->error = "Only one raid4/5/6 'journal_mode' argument allowed";
1285 				return -EINVAL;
1286 			}
1287 			r = dm_raid_journal_mode_to_md(arg);
1288 			if (r < 0) {
1289 				rs->ti->error = "Invalid 'journal_mode' argument";
1290 				return r;
1291 			}
1292 			rs->journal_dev.mode = r;
1293 			continue;
1294 		}
1295 
1296 		/*
1297 		 * Parameters with number values from here on.
1298 		 */
1299 		if (kstrtoint(arg, 10, &value) < 0) {
1300 			rs->ti->error = "Bad numerical argument given in raid params";
1301 			return -EINVAL;
1302 		}
1303 
1304 		if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_REBUILD))) {
1305 			/*
1306 			 * "rebuild" is being passed in by userspace to provide
1307 			 * indexes of replaced devices and to set up additional
1308 			 * devices on raid level takeover.
1309 			 */
1310 			if (!__within_range(value, 0, rs->raid_disks - 1)) {
1311 				rs->ti->error = "Invalid rebuild index given";
1312 				return -EINVAL;
1313 			}
1314 
1315 			if (test_and_set_bit(value, (void *) rs->rebuild_disks)) {
1316 				rs->ti->error = "rebuild for this index already given";
1317 				return -EINVAL;
1318 			}
1319 
1320 			rd = rs->dev + value;
1321 			clear_bit(In_sync, &rd->rdev.flags);
1322 			clear_bit(Faulty, &rd->rdev.flags);
1323 			rd->rdev.recovery_offset = 0;
1324 			set_bit(__CTR_FLAG_REBUILD, &rs->ctr_flags);
1325 		} else if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_WRITE_MOSTLY))) {
1326 			if (!rt_is_raid1(rt)) {
1327 				rs->ti->error = "write_mostly option is only valid for RAID1";
1328 				return -EINVAL;
1329 			}
1330 
1331 			if (!__within_range(value, 0, rs->md.raid_disks - 1)) {
1332 				rs->ti->error = "Invalid write_mostly index given";
1333 				return -EINVAL;
1334 			}
1335 
1336 			write_mostly++;
1337 			set_bit(WriteMostly, &rs->dev[value].rdev.flags);
1338 			set_bit(__CTR_FLAG_WRITE_MOSTLY, &rs->ctr_flags);
1339 		} else if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_MAX_WRITE_BEHIND))) {
1340 			if (!rt_is_raid1(rt)) {
1341 				rs->ti->error = "max_write_behind option is only valid for RAID1";
1342 				return -EINVAL;
1343 			}
1344 
1345 			if (test_and_set_bit(__CTR_FLAG_MAX_WRITE_BEHIND, &rs->ctr_flags)) {
1346 				rs->ti->error = "Only one max_write_behind argument pair allowed";
1347 				return -EINVAL;
1348 			}
1349 
1350 			/*
1351 			 * In device-mapper, we specify things in sectors, but
1352 			 * MD records this value in kB
1353 			 */
1354 			if (value < 0 || value / 2 > COUNTER_MAX) {
1355 				rs->ti->error = "Max write-behind limit out of range";
1356 				return -EINVAL;
1357 			}
1358 
1359 			rs->md.bitmap_info.max_write_behind = value / 2;
1360 		} else if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_DAEMON_SLEEP))) {
1361 			if (test_and_set_bit(__CTR_FLAG_DAEMON_SLEEP, &rs->ctr_flags)) {
1362 				rs->ti->error = "Only one daemon_sleep argument pair allowed";
1363 				return -EINVAL;
1364 			}
1365 			if (value < 0) {
1366 				rs->ti->error = "daemon sleep period out of range";
1367 				return -EINVAL;
1368 			}
1369 			rs->md.bitmap_info.daemon_sleep = value;
1370 		} else if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_DATA_OFFSET))) {
1371 			/* Userspace passes new data_offset after having extended the the data image LV */
1372 			if (test_and_set_bit(__CTR_FLAG_DATA_OFFSET, &rs->ctr_flags)) {
1373 				rs->ti->error = "Only one data_offset argument pair allowed";
1374 				return -EINVAL;
1375 			}
1376 			/* Ensure sensible data offset */
1377 			if (value < 0 ||
1378 			    (value && (value < MIN_FREE_RESHAPE_SPACE || value % to_sector(PAGE_SIZE)))) {
1379 				rs->ti->error = "Bogus data_offset value";
1380 				return -EINVAL;
1381 			}
1382 			rs->data_offset = value;
1383 		} else if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_DELTA_DISKS))) {
1384 			/* Define the +/-# of disks to add to/remove from the given raid set */
1385 			if (test_and_set_bit(__CTR_FLAG_DELTA_DISKS, &rs->ctr_flags)) {
1386 				rs->ti->error = "Only one delta_disks argument pair allowed";
1387 				return -EINVAL;
1388 			}
1389 			/* Ensure MAX_RAID_DEVICES and raid type minimal_devs! */
1390 			if (!__within_range(abs(value), 1, MAX_RAID_DEVICES - rt->minimal_devs)) {
1391 				rs->ti->error = "Too many delta_disk requested";
1392 				return -EINVAL;
1393 			}
1394 
1395 			rs->delta_disks = value;
1396 		} else if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_STRIPE_CACHE))) {
1397 			if (test_and_set_bit(__CTR_FLAG_STRIPE_CACHE, &rs->ctr_flags)) {
1398 				rs->ti->error = "Only one stripe_cache argument pair allowed";
1399 				return -EINVAL;
1400 			}
1401 
1402 			if (!rt_is_raid456(rt)) {
1403 				rs->ti->error = "Inappropriate argument: stripe_cache";
1404 				return -EINVAL;
1405 			}
1406 
1407 			if (value < 0) {
1408 				rs->ti->error = "Bogus stripe cache entries value";
1409 				return -EINVAL;
1410 			}
1411 			rs->stripe_cache_entries = value;
1412 		} else if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_MIN_RECOVERY_RATE))) {
1413 			if (test_and_set_bit(__CTR_FLAG_MIN_RECOVERY_RATE, &rs->ctr_flags)) {
1414 				rs->ti->error = "Only one min_recovery_rate argument pair allowed";
1415 				return -EINVAL;
1416 			}
1417 
1418 			if (value < 0) {
1419 				rs->ti->error = "min_recovery_rate out of range";
1420 				return -EINVAL;
1421 			}
1422 			rs->md.sync_speed_min = value;
1423 		} else if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_MAX_RECOVERY_RATE))) {
1424 			if (test_and_set_bit(__CTR_FLAG_MAX_RECOVERY_RATE, &rs->ctr_flags)) {
1425 				rs->ti->error = "Only one max_recovery_rate argument pair allowed";
1426 				return -EINVAL;
1427 			}
1428 
1429 			if (value < 0) {
1430 				rs->ti->error = "max_recovery_rate out of range";
1431 				return -EINVAL;
1432 			}
1433 			rs->md.sync_speed_max = value;
1434 		} else if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_REGION_SIZE))) {
1435 			if (test_and_set_bit(__CTR_FLAG_REGION_SIZE, &rs->ctr_flags)) {
1436 				rs->ti->error = "Only one region_size argument pair allowed";
1437 				return -EINVAL;
1438 			}
1439 
1440 			region_size = value;
1441 			rs->requested_bitmap_chunk_sectors = value;
1442 		} else if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_RAID10_COPIES))) {
1443 			if (test_and_set_bit(__CTR_FLAG_RAID10_COPIES, &rs->ctr_flags)) {
1444 				rs->ti->error = "Only one raid10_copies argument pair allowed";
1445 				return -EINVAL;
1446 			}
1447 
1448 			if (!__within_range(value, 2, rs->md.raid_disks)) {
1449 				rs->ti->error = "Bad value for 'raid10_copies'";
1450 				return -EINVAL;
1451 			}
1452 
1453 			raid10_copies = value;
1454 		} else {
1455 			DMERR("Unable to parse RAID parameter: %s", key);
1456 			rs->ti->error = "Unable to parse RAID parameter";
1457 			return -EINVAL;
1458 		}
1459 	}
1460 
1461 	if (test_bit(__CTR_FLAG_SYNC, &rs->ctr_flags) &&
1462 	    test_bit(__CTR_FLAG_NOSYNC, &rs->ctr_flags)) {
1463 		rs->ti->error = "sync and nosync are mutually exclusive";
1464 		return -EINVAL;
1465 	}
1466 
1467 	if (test_bit(__CTR_FLAG_REBUILD, &rs->ctr_flags) &&
1468 	    (test_bit(__CTR_FLAG_SYNC, &rs->ctr_flags) ||
1469 	     test_bit(__CTR_FLAG_NOSYNC, &rs->ctr_flags))) {
1470 		rs->ti->error = "sync/nosync and rebuild are mutually exclusive";
1471 		return -EINVAL;
1472 	}
1473 
1474 	if (write_mostly >= rs->md.raid_disks) {
1475 		rs->ti->error = "Can't set all raid1 devices to write_mostly";
1476 		return -EINVAL;
1477 	}
1478 
1479 	if (rs->md.sync_speed_max &&
1480 	    rs->md.sync_speed_min > rs->md.sync_speed_max) {
1481 		rs->ti->error = "Bogus recovery rates";
1482 		return -EINVAL;
1483 	}
1484 
1485 	if (validate_region_size(rs, region_size))
1486 		return -EINVAL;
1487 
1488 	if (rs->md.chunk_sectors)
1489 		max_io_len = rs->md.chunk_sectors;
1490 	else
1491 		max_io_len = region_size;
1492 
1493 	if (dm_set_target_max_io_len(rs->ti, max_io_len))
1494 		return -EINVAL;
1495 
1496 	if (rt_is_raid10(rt)) {
1497 		if (raid10_copies > rs->md.raid_disks) {
1498 			rs->ti->error = "Not enough devices to satisfy specification";
1499 			return -EINVAL;
1500 		}
1501 
1502 		rs->md.new_layout = raid10_format_to_md_layout(rs, raid10_format, raid10_copies);
1503 		if (rs->md.new_layout < 0) {
1504 			rs->ti->error = "Error getting raid10 format";
1505 			return rs->md.new_layout;
1506 		}
1507 
1508 		rt = get_raid_type_by_ll(10, rs->md.new_layout);
1509 		if (!rt) {
1510 			rs->ti->error = "Failed to recognize new raid10 layout";
1511 			return -EINVAL;
1512 		}
1513 
1514 		if ((rt->algorithm == ALGORITHM_RAID10_DEFAULT ||
1515 		     rt->algorithm == ALGORITHM_RAID10_NEAR) &&
1516 		    test_bit(__CTR_FLAG_RAID10_USE_NEAR_SETS, &rs->ctr_flags)) {
1517 			rs->ti->error = "RAID10 format 'near' and 'raid10_use_near_sets' are incompatible";
1518 			return -EINVAL;
1519 		}
1520 	}
1521 
1522 	rs->raid10_copies = raid10_copies;
1523 
1524 	/* Assume there are no metadata devices until the drives are parsed */
1525 	rs->md.persistent = 0;
1526 	rs->md.external = 1;
1527 
1528 	/* Check, if any invalid ctr arguments have been passed in for the raid level */
1529 	return rs_check_for_valid_flags(rs);
1530 }
1531 
1532 /* Set raid4/5/6 cache size */
1533 static int rs_set_raid456_stripe_cache(struct raid_set *rs)
1534 {
1535 	int r;
1536 	struct r5conf *conf;
1537 	struct mddev *mddev = &rs->md;
1538 	uint32_t min_stripes = max(mddev->chunk_sectors, mddev->new_chunk_sectors) / 2;
1539 	uint32_t nr_stripes = rs->stripe_cache_entries;
1540 
1541 	if (!rt_is_raid456(rs->raid_type)) {
1542 		rs->ti->error = "Inappropriate raid level; cannot change stripe_cache size";
1543 		return -EINVAL;
1544 	}
1545 
1546 	if (nr_stripes < min_stripes) {
1547 		DMINFO("Adjusting requested %u stripe cache entries to %u to suit stripe size",
1548 		       nr_stripes, min_stripes);
1549 		nr_stripes = min_stripes;
1550 	}
1551 
1552 	conf = mddev->private;
1553 	if (!conf) {
1554 		rs->ti->error = "Cannot change stripe_cache size on inactive RAID set";
1555 		return -EINVAL;
1556 	}
1557 
1558 	/* Try setting number of stripes in raid456 stripe cache */
1559 	if (conf->min_nr_stripes != nr_stripes) {
1560 		r = raid5_set_cache_size(mddev, nr_stripes);
1561 		if (r) {
1562 			rs->ti->error = "Failed to set raid4/5/6 stripe cache size";
1563 			return r;
1564 		}
1565 
1566 		DMINFO("%u stripe cache entries", nr_stripes);
1567 	}
1568 
1569 	return 0;
1570 }
1571 
1572 /* Return # of data stripes as kept in mddev as of @rs (i.e. as of superblock) */
1573 static unsigned int mddev_data_stripes(struct raid_set *rs)
1574 {
1575 	return rs->md.raid_disks - rs->raid_type->parity_devs;
1576 }
1577 
1578 /* Return # of data stripes of @rs (i.e. as of ctr) */
1579 static unsigned int rs_data_stripes(struct raid_set *rs)
1580 {
1581 	return rs->raid_disks - rs->raid_type->parity_devs;
1582 }
1583 
1584 /*
1585  * Retrieve rdev->sectors from any valid raid device of @rs
1586  * to allow userpace to pass in arbitray "- -" device tupples.
1587  */
1588 static sector_t __rdev_sectors(struct raid_set *rs)
1589 {
1590 	int i;
1591 
1592 	for (i = 0; i < rs->md.raid_disks; i++) {
1593 		struct md_rdev *rdev = &rs->dev[i].rdev;
1594 
1595 		if (!test_bit(Journal, &rdev->flags) &&
1596 		    rdev->bdev && rdev->sectors)
1597 			return rdev->sectors;
1598 	}
1599 
1600 	return 0;
1601 }
1602 
1603 /* Check that calculated dev_sectors fits all component devices. */
1604 static int _check_data_dev_sectors(struct raid_set *rs)
1605 {
1606 	sector_t ds = ~0;
1607 	struct md_rdev *rdev;
1608 
1609 	rdev_for_each(rdev, &rs->md)
1610 		if (!test_bit(Journal, &rdev->flags) && rdev->bdev) {
1611 			ds = min(ds, to_sector(i_size_read(rdev->bdev->bd_inode)));
1612 			if (ds < rs->md.dev_sectors) {
1613 				rs->ti->error = "Component device(s) too small";
1614 				return -EINVAL;
1615 			}
1616 		}
1617 
1618 	return 0;
1619 }
1620 
1621 /* Calculate the sectors per device and per array used for @rs */
1622 static int rs_set_dev_and_array_sectors(struct raid_set *rs, sector_t sectors, bool use_mddev)
1623 {
1624 	int delta_disks;
1625 	unsigned int data_stripes;
1626 	sector_t array_sectors = sectors, dev_sectors = sectors;
1627 	struct mddev *mddev = &rs->md;
1628 
1629 	if (use_mddev) {
1630 		delta_disks = mddev->delta_disks;
1631 		data_stripes = mddev_data_stripes(rs);
1632 	} else {
1633 		delta_disks = rs->delta_disks;
1634 		data_stripes = rs_data_stripes(rs);
1635 	}
1636 
1637 	/* Special raid1 case w/o delta_disks support (yet) */
1638 	if (rt_is_raid1(rs->raid_type))
1639 		;
1640 	else if (rt_is_raid10(rs->raid_type)) {
1641 		if (rs->raid10_copies < 2 ||
1642 		    delta_disks < 0) {
1643 			rs->ti->error = "Bogus raid10 data copies or delta disks";
1644 			return -EINVAL;
1645 		}
1646 
1647 		dev_sectors *= rs->raid10_copies;
1648 		if (sector_div(dev_sectors, data_stripes))
1649 			goto bad;
1650 
1651 		array_sectors = (data_stripes + delta_disks) * dev_sectors;
1652 		if (sector_div(array_sectors, rs->raid10_copies))
1653 			goto bad;
1654 
1655 	} else if (sector_div(dev_sectors, data_stripes))
1656 		goto bad;
1657 
1658 	else
1659 		/* Striped layouts */
1660 		array_sectors = (data_stripes + delta_disks) * dev_sectors;
1661 
1662 	mddev->array_sectors = array_sectors;
1663 	mddev->dev_sectors = dev_sectors;
1664 	rs_set_rdev_sectors(rs);
1665 
1666 	return _check_data_dev_sectors(rs);
1667 bad:
1668 	rs->ti->error = "Target length not divisible by number of data devices";
1669 	return -EINVAL;
1670 }
1671 
1672 /* Setup recovery on @rs */
1673 static void rs_setup_recovery(struct raid_set *rs, sector_t dev_sectors)
1674 {
1675 	/* raid0 does not recover */
1676 	if (rs_is_raid0(rs))
1677 		rs->md.recovery_cp = MaxSector;
1678 	/*
1679 	 * A raid6 set has to be recovered either
1680 	 * completely or for the grown part to
1681 	 * ensure proper parity and Q-Syndrome
1682 	 */
1683 	else if (rs_is_raid6(rs))
1684 		rs->md.recovery_cp = dev_sectors;
1685 	/*
1686 	 * Other raid set types may skip recovery
1687 	 * depending on the 'nosync' flag.
1688 	 */
1689 	else
1690 		rs->md.recovery_cp = test_bit(__CTR_FLAG_NOSYNC, &rs->ctr_flags)
1691 				     ? MaxSector : dev_sectors;
1692 }
1693 
1694 static void do_table_event(struct work_struct *ws)
1695 {
1696 	struct raid_set *rs = container_of(ws, struct raid_set, md.event_work);
1697 
1698 	smp_rmb(); /* Make sure we access most actual mddev properties */
1699 	if (!rs_is_reshaping(rs)) {
1700 		if (rs_is_raid10(rs))
1701 			rs_set_rdev_sectors(rs);
1702 		rs_set_capacity(rs);
1703 	}
1704 	dm_table_event(rs->ti->table);
1705 }
1706 
1707 /*
1708  * Make sure a valid takover (level switch) is being requested on @rs
1709  *
1710  * Conversions of raid sets from one MD personality to another
1711  * have to conform to restrictions which are enforced here.
1712  */
1713 static int rs_check_takeover(struct raid_set *rs)
1714 {
1715 	struct mddev *mddev = &rs->md;
1716 	unsigned int near_copies;
1717 
1718 	if (rs->md.degraded) {
1719 		rs->ti->error = "Can't takeover degraded raid set";
1720 		return -EPERM;
1721 	}
1722 
1723 	if (rs_is_reshaping(rs)) {
1724 		rs->ti->error = "Can't takeover reshaping raid set";
1725 		return -EPERM;
1726 	}
1727 
1728 	switch (mddev->level) {
1729 	case 0:
1730 		/* raid0 -> raid1/5 with one disk */
1731 		if ((mddev->new_level == 1 || mddev->new_level == 5) &&
1732 		    mddev->raid_disks == 1)
1733 			return 0;
1734 
1735 		/* raid0 -> raid10 */
1736 		if (mddev->new_level == 10 &&
1737 		    !(rs->raid_disks % mddev->raid_disks))
1738 			return 0;
1739 
1740 		/* raid0 with multiple disks -> raid4/5/6 */
1741 		if (__within_range(mddev->new_level, 4, 6) &&
1742 		    mddev->new_layout == ALGORITHM_PARITY_N &&
1743 		    mddev->raid_disks > 1)
1744 			return 0;
1745 
1746 		break;
1747 
1748 	case 10:
1749 		/* Can't takeover raid10_offset! */
1750 		if (__is_raid10_offset(mddev->layout))
1751 			break;
1752 
1753 		near_copies = __raid10_near_copies(mddev->layout);
1754 
1755 		/* raid10* -> raid0 */
1756 		if (mddev->new_level == 0) {
1757 			/* Can takeover raid10_near with raid disks divisable by data copies! */
1758 			if (near_copies > 1 &&
1759 			    !(mddev->raid_disks % near_copies)) {
1760 				mddev->raid_disks /= near_copies;
1761 				mddev->delta_disks = mddev->raid_disks;
1762 				return 0;
1763 			}
1764 
1765 			/* Can takeover raid10_far */
1766 			if (near_copies == 1 &&
1767 			    __raid10_far_copies(mddev->layout) > 1)
1768 				return 0;
1769 
1770 			break;
1771 		}
1772 
1773 		/* raid10_{near,far} -> raid1 */
1774 		if (mddev->new_level == 1 &&
1775 		    max(near_copies, __raid10_far_copies(mddev->layout)) == mddev->raid_disks)
1776 			return 0;
1777 
1778 		/* raid10_{near,far} with 2 disks -> raid4/5 */
1779 		if (__within_range(mddev->new_level, 4, 5) &&
1780 		    mddev->raid_disks == 2)
1781 			return 0;
1782 		break;
1783 
1784 	case 1:
1785 		/* raid1 with 2 disks -> raid4/5 */
1786 		if (__within_range(mddev->new_level, 4, 5) &&
1787 		    mddev->raid_disks == 2) {
1788 			mddev->degraded = 1;
1789 			return 0;
1790 		}
1791 
1792 		/* raid1 -> raid0 */
1793 		if (mddev->new_level == 0 &&
1794 		    mddev->raid_disks == 1)
1795 			return 0;
1796 
1797 		/* raid1 -> raid10 */
1798 		if (mddev->new_level == 10)
1799 			return 0;
1800 		break;
1801 
1802 	case 4:
1803 		/* raid4 -> raid0 */
1804 		if (mddev->new_level == 0)
1805 			return 0;
1806 
1807 		/* raid4 -> raid1/5 with 2 disks */
1808 		if ((mddev->new_level == 1 || mddev->new_level == 5) &&
1809 		    mddev->raid_disks == 2)
1810 			return 0;
1811 
1812 		/* raid4 -> raid5/6 with parity N */
1813 		if (__within_range(mddev->new_level, 5, 6) &&
1814 		    mddev->layout == ALGORITHM_PARITY_N)
1815 			return 0;
1816 		break;
1817 
1818 	case 5:
1819 		/* raid5 with parity N -> raid0 */
1820 		if (mddev->new_level == 0 &&
1821 		    mddev->layout == ALGORITHM_PARITY_N)
1822 			return 0;
1823 
1824 		/* raid5 with parity N -> raid4 */
1825 		if (mddev->new_level == 4 &&
1826 		    mddev->layout == ALGORITHM_PARITY_N)
1827 			return 0;
1828 
1829 		/* raid5 with 2 disks -> raid1/4/10 */
1830 		if ((mddev->new_level == 1 || mddev->new_level == 4 || mddev->new_level == 10) &&
1831 		    mddev->raid_disks == 2)
1832 			return 0;
1833 
1834 		/* raid5_* ->  raid6_*_6 with Q-Syndrome N (e.g. raid5_ra -> raid6_ra_6 */
1835 		if (mddev->new_level == 6 &&
1836 		    ((mddev->layout == ALGORITHM_PARITY_N && mddev->new_layout == ALGORITHM_PARITY_N) ||
1837 		      __within_range(mddev->new_layout, ALGORITHM_LEFT_ASYMMETRIC_6, ALGORITHM_RIGHT_SYMMETRIC_6)))
1838 			return 0;
1839 		break;
1840 
1841 	case 6:
1842 		/* raid6 with parity N -> raid0 */
1843 		if (mddev->new_level == 0 &&
1844 		    mddev->layout == ALGORITHM_PARITY_N)
1845 			return 0;
1846 
1847 		/* raid6 with parity N -> raid4 */
1848 		if (mddev->new_level == 4 &&
1849 		    mddev->layout == ALGORITHM_PARITY_N)
1850 			return 0;
1851 
1852 		/* raid6_*_n with Q-Syndrome N -> raid5_* */
1853 		if (mddev->new_level == 5 &&
1854 		    ((mddev->layout == ALGORITHM_PARITY_N && mddev->new_layout == ALGORITHM_PARITY_N) ||
1855 		     __within_range(mddev->new_layout, ALGORITHM_LEFT_ASYMMETRIC, ALGORITHM_RIGHT_SYMMETRIC)))
1856 			return 0;
1857 
1858 	default:
1859 		break;
1860 	}
1861 
1862 	rs->ti->error = "takeover not possible";
1863 	return -EINVAL;
1864 }
1865 
1866 /* True if @rs requested to be taken over */
1867 static bool rs_takeover_requested(struct raid_set *rs)
1868 {
1869 	return rs->md.new_level != rs->md.level;
1870 }
1871 
1872 /* True if @rs is requested to reshape by ctr */
1873 static bool rs_reshape_requested(struct raid_set *rs)
1874 {
1875 	bool change;
1876 	struct mddev *mddev = &rs->md;
1877 
1878 	if (rs_takeover_requested(rs))
1879 		return false;
1880 
1881 	if (rs_is_raid0(rs))
1882 		return false;
1883 
1884 	change = mddev->new_layout != mddev->layout ||
1885 		 mddev->new_chunk_sectors != mddev->chunk_sectors ||
1886 		 rs->delta_disks;
1887 
1888 	/* Historical case to support raid1 reshape without delta disks */
1889 	if (rs_is_raid1(rs)) {
1890 		if (rs->delta_disks)
1891 			return !!rs->delta_disks;
1892 
1893 		return !change &&
1894 		       mddev->raid_disks != rs->raid_disks;
1895 	}
1896 
1897 	if (rs_is_raid10(rs))
1898 		return change &&
1899 		       !__is_raid10_far(mddev->new_layout) &&
1900 		       rs->delta_disks >= 0;
1901 
1902 	return change;
1903 }
1904 
1905 /*  Features */
1906 #define	FEATURE_FLAG_SUPPORTS_V190	0x1 /* Supports extended superblock */
1907 
1908 /* State flags for sb->flags */
1909 #define	SB_FLAG_RESHAPE_ACTIVE		0x1
1910 #define	SB_FLAG_RESHAPE_BACKWARDS	0x2
1911 
1912 /*
1913  * This structure is never routinely used by userspace, unlike md superblocks.
1914  * Devices with this superblock should only ever be accessed via device-mapper.
1915  */
1916 #define DM_RAID_MAGIC 0x64526D44
1917 struct dm_raid_superblock {
1918 	__le32 magic;		/* "DmRd" */
1919 	__le32 compat_features;	/* Used to indicate compatible features (like 1.9.0 ondisk metadata extension) */
1920 
1921 	__le32 num_devices;	/* Number of devices in this raid set. (Max 64) */
1922 	__le32 array_position;	/* The position of this drive in the raid set */
1923 
1924 	__le64 events;		/* Incremented by md when superblock updated */
1925 	__le64 failed_devices;	/* Pre 1.9.0 part of bit field of devices to */
1926 				/* indicate failures (see extension below) */
1927 
1928 	/*
1929 	 * This offset tracks the progress of the repair or replacement of
1930 	 * an individual drive.
1931 	 */
1932 	__le64 disk_recovery_offset;
1933 
1934 	/*
1935 	 * This offset tracks the progress of the initial raid set
1936 	 * synchronisation/parity calculation.
1937 	 */
1938 	__le64 array_resync_offset;
1939 
1940 	/*
1941 	 * raid characteristics
1942 	 */
1943 	__le32 level;
1944 	__le32 layout;
1945 	__le32 stripe_sectors;
1946 
1947 	/********************************************************************
1948 	 * BELOW FOLLOW V1.9.0 EXTENSIONS TO THE PRISTINE SUPERBLOCK FORMAT!!!
1949 	 *
1950 	 * FEATURE_FLAG_SUPPORTS_V190 in the compat_features member indicates that those exist
1951 	 */
1952 
1953 	__le32 flags; /* Flags defining array states for reshaping */
1954 
1955 	/*
1956 	 * This offset tracks the progress of a raid
1957 	 * set reshape in order to be able to restart it
1958 	 */
1959 	__le64 reshape_position;
1960 
1961 	/*
1962 	 * These define the properties of the array in case of an interrupted reshape
1963 	 */
1964 	__le32 new_level;
1965 	__le32 new_layout;
1966 	__le32 new_stripe_sectors;
1967 	__le32 delta_disks;
1968 
1969 	__le64 array_sectors; /* Array size in sectors */
1970 
1971 	/*
1972 	 * Sector offsets to data on devices (reshaping).
1973 	 * Needed to support out of place reshaping, thus
1974 	 * not writing over any stripes whilst converting
1975 	 * them from old to new layout
1976 	 */
1977 	__le64 data_offset;
1978 	__le64 new_data_offset;
1979 
1980 	__le64 sectors; /* Used device size in sectors */
1981 
1982 	/*
1983 	 * Additonal Bit field of devices indicating failures to support
1984 	 * up to 256 devices with the 1.9.0 on-disk metadata format
1985 	 */
1986 	__le64 extended_failed_devices[DISKS_ARRAY_ELEMS - 1];
1987 
1988 	__le32 incompat_features;	/* Used to indicate any incompatible features */
1989 
1990 	/* Always set rest up to logical block size to 0 when writing (see get_metadata_device() below). */
1991 } __packed;
1992 
1993 /*
1994  * Check for reshape constraints on raid set @rs:
1995  *
1996  * - reshape function non-existent
1997  * - degraded set
1998  * - ongoing recovery
1999  * - ongoing reshape
2000  *
2001  * Returns 0 if none or -EPERM if given constraint
2002  * and error message reference in @errmsg
2003  */
2004 static int rs_check_reshape(struct raid_set *rs)
2005 {
2006 	struct mddev *mddev = &rs->md;
2007 
2008 	if (!mddev->pers || !mddev->pers->check_reshape)
2009 		rs->ti->error = "Reshape not supported";
2010 	else if (mddev->degraded)
2011 		rs->ti->error = "Can't reshape degraded raid set";
2012 	else if (rs_is_recovering(rs))
2013 		rs->ti->error = "Convert request on recovering raid set prohibited";
2014 	else if (rs_is_reshaping(rs))
2015 		rs->ti->error = "raid set already reshaping!";
2016 	else if (!(rs_is_raid1(rs) || rs_is_raid10(rs) || rs_is_raid456(rs)))
2017 		rs->ti->error = "Reshaping only supported for raid1/4/5/6/10";
2018 	else
2019 		return 0;
2020 
2021 	return -EPERM;
2022 }
2023 
2024 static int read_disk_sb(struct md_rdev *rdev, int size, bool force_reload)
2025 {
2026 	BUG_ON(!rdev->sb_page);
2027 
2028 	if (rdev->sb_loaded && !force_reload)
2029 		return 0;
2030 
2031 	rdev->sb_loaded = 0;
2032 
2033 	if (!sync_page_io(rdev, 0, size, rdev->sb_page, REQ_OP_READ, 0, true)) {
2034 		DMERR("Failed to read superblock of device at position %d",
2035 		      rdev->raid_disk);
2036 		md_error(rdev->mddev, rdev);
2037 		set_bit(Faulty, &rdev->flags);
2038 		return -EIO;
2039 	}
2040 
2041 	rdev->sb_loaded = 1;
2042 
2043 	return 0;
2044 }
2045 
2046 static void sb_retrieve_failed_devices(struct dm_raid_superblock *sb, uint64_t *failed_devices)
2047 {
2048 	failed_devices[0] = le64_to_cpu(sb->failed_devices);
2049 	memset(failed_devices + 1, 0, sizeof(sb->extended_failed_devices));
2050 
2051 	if (le32_to_cpu(sb->compat_features) & FEATURE_FLAG_SUPPORTS_V190) {
2052 		int i = ARRAY_SIZE(sb->extended_failed_devices);
2053 
2054 		while (i--)
2055 			failed_devices[i+1] = le64_to_cpu(sb->extended_failed_devices[i]);
2056 	}
2057 }
2058 
2059 static void sb_update_failed_devices(struct dm_raid_superblock *sb, uint64_t *failed_devices)
2060 {
2061 	int i = ARRAY_SIZE(sb->extended_failed_devices);
2062 
2063 	sb->failed_devices = cpu_to_le64(failed_devices[0]);
2064 	while (i--)
2065 		sb->extended_failed_devices[i] = cpu_to_le64(failed_devices[i+1]);
2066 }
2067 
2068 /*
2069  * Synchronize the superblock members with the raid set properties
2070  *
2071  * All superblock data is little endian.
2072  */
2073 static void super_sync(struct mddev *mddev, struct md_rdev *rdev)
2074 {
2075 	bool update_failed_devices = false;
2076 	unsigned int i;
2077 	uint64_t failed_devices[DISKS_ARRAY_ELEMS];
2078 	struct dm_raid_superblock *sb;
2079 	struct raid_set *rs = container_of(mddev, struct raid_set, md);
2080 
2081 	/* No metadata device, no superblock */
2082 	if (!rdev->meta_bdev)
2083 		return;
2084 
2085 	BUG_ON(!rdev->sb_page);
2086 
2087 	sb = page_address(rdev->sb_page);
2088 
2089 	sb_retrieve_failed_devices(sb, failed_devices);
2090 
2091 	for (i = 0; i < rs->raid_disks; i++)
2092 		if (!rs->dev[i].data_dev || test_bit(Faulty, &rs->dev[i].rdev.flags)) {
2093 			update_failed_devices = true;
2094 			set_bit(i, (void *) failed_devices);
2095 		}
2096 
2097 	if (update_failed_devices)
2098 		sb_update_failed_devices(sb, failed_devices);
2099 
2100 	sb->magic = cpu_to_le32(DM_RAID_MAGIC);
2101 	sb->compat_features = cpu_to_le32(FEATURE_FLAG_SUPPORTS_V190);
2102 
2103 	sb->num_devices = cpu_to_le32(mddev->raid_disks);
2104 	sb->array_position = cpu_to_le32(rdev->raid_disk);
2105 
2106 	sb->events = cpu_to_le64(mddev->events);
2107 
2108 	sb->disk_recovery_offset = cpu_to_le64(rdev->recovery_offset);
2109 	sb->array_resync_offset = cpu_to_le64(mddev->recovery_cp);
2110 
2111 	sb->level = cpu_to_le32(mddev->level);
2112 	sb->layout = cpu_to_le32(mddev->layout);
2113 	sb->stripe_sectors = cpu_to_le32(mddev->chunk_sectors);
2114 
2115 	/********************************************************************
2116 	 * BELOW FOLLOW V1.9.0 EXTENSIONS TO THE PRISTINE SUPERBLOCK FORMAT!!!
2117 	 *
2118 	 * FEATURE_FLAG_SUPPORTS_V190 in the compat_features member indicates that those exist
2119 	 */
2120 	sb->new_level = cpu_to_le32(mddev->new_level);
2121 	sb->new_layout = cpu_to_le32(mddev->new_layout);
2122 	sb->new_stripe_sectors = cpu_to_le32(mddev->new_chunk_sectors);
2123 
2124 	sb->delta_disks = cpu_to_le32(mddev->delta_disks);
2125 
2126 	smp_rmb(); /* Make sure we access most recent reshape position */
2127 	sb->reshape_position = cpu_to_le64(mddev->reshape_position);
2128 	if (le64_to_cpu(sb->reshape_position) != MaxSector) {
2129 		/* Flag ongoing reshape */
2130 		sb->flags |= cpu_to_le32(SB_FLAG_RESHAPE_ACTIVE);
2131 
2132 		if (mddev->delta_disks < 0 || mddev->reshape_backwards)
2133 			sb->flags |= cpu_to_le32(SB_FLAG_RESHAPE_BACKWARDS);
2134 	} else {
2135 		/* Clear reshape flags */
2136 		sb->flags &= ~(cpu_to_le32(SB_FLAG_RESHAPE_ACTIVE|SB_FLAG_RESHAPE_BACKWARDS));
2137 	}
2138 
2139 	sb->array_sectors = cpu_to_le64(mddev->array_sectors);
2140 	sb->data_offset = cpu_to_le64(rdev->data_offset);
2141 	sb->new_data_offset = cpu_to_le64(rdev->new_data_offset);
2142 	sb->sectors = cpu_to_le64(rdev->sectors);
2143 	sb->incompat_features = cpu_to_le32(0);
2144 
2145 	/* Zero out the rest of the payload after the size of the superblock */
2146 	memset(sb + 1, 0, rdev->sb_size - sizeof(*sb));
2147 }
2148 
2149 /*
2150  * super_load
2151  *
2152  * This function creates a superblock if one is not found on the device
2153  * and will decide which superblock to use if there's a choice.
2154  *
2155  * Return: 1 if use rdev, 0 if use refdev, -Exxx otherwise
2156  */
2157 static int super_load(struct md_rdev *rdev, struct md_rdev *refdev)
2158 {
2159 	int r;
2160 	struct dm_raid_superblock *sb;
2161 	struct dm_raid_superblock *refsb;
2162 	uint64_t events_sb, events_refsb;
2163 
2164 	r = read_disk_sb(rdev, rdev->sb_size, false);
2165 	if (r)
2166 		return r;
2167 
2168 	sb = page_address(rdev->sb_page);
2169 
2170 	/*
2171 	 * Two cases that we want to write new superblocks and rebuild:
2172 	 * 1) New device (no matching magic number)
2173 	 * 2) Device specified for rebuild (!In_sync w/ offset == 0)
2174 	 */
2175 	if ((sb->magic != cpu_to_le32(DM_RAID_MAGIC)) ||
2176 	    (!test_bit(In_sync, &rdev->flags) && !rdev->recovery_offset)) {
2177 		super_sync(rdev->mddev, rdev);
2178 
2179 		set_bit(FirstUse, &rdev->flags);
2180 		sb->compat_features = cpu_to_le32(FEATURE_FLAG_SUPPORTS_V190);
2181 
2182 		/* Force writing of superblocks to disk */
2183 		set_bit(MD_SB_CHANGE_DEVS, &rdev->mddev->sb_flags);
2184 
2185 		/* Any superblock is better than none, choose that if given */
2186 		return refdev ? 0 : 1;
2187 	}
2188 
2189 	if (!refdev)
2190 		return 1;
2191 
2192 	events_sb = le64_to_cpu(sb->events);
2193 
2194 	refsb = page_address(refdev->sb_page);
2195 	events_refsb = le64_to_cpu(refsb->events);
2196 
2197 	return (events_sb > events_refsb) ? 1 : 0;
2198 }
2199 
2200 static int super_init_validation(struct raid_set *rs, struct md_rdev *rdev)
2201 {
2202 	int role;
2203 	unsigned int d;
2204 	struct mddev *mddev = &rs->md;
2205 	uint64_t events_sb;
2206 	uint64_t failed_devices[DISKS_ARRAY_ELEMS];
2207 	struct dm_raid_superblock *sb;
2208 	uint32_t new_devs = 0, rebuild_and_new = 0, rebuilds = 0;
2209 	struct md_rdev *r;
2210 	struct dm_raid_superblock *sb2;
2211 
2212 	sb = page_address(rdev->sb_page);
2213 	events_sb = le64_to_cpu(sb->events);
2214 
2215 	/*
2216 	 * Initialise to 1 if this is a new superblock.
2217 	 */
2218 	mddev->events = events_sb ? : 1;
2219 
2220 	mddev->reshape_position = MaxSector;
2221 
2222 	mddev->raid_disks = le32_to_cpu(sb->num_devices);
2223 	mddev->level = le32_to_cpu(sb->level);
2224 	mddev->layout = le32_to_cpu(sb->layout);
2225 	mddev->chunk_sectors = le32_to_cpu(sb->stripe_sectors);
2226 
2227 	/*
2228 	 * Reshaping is supported, e.g. reshape_position is valid
2229 	 * in superblock and superblock content is authoritative.
2230 	 */
2231 	if (le32_to_cpu(sb->compat_features) & FEATURE_FLAG_SUPPORTS_V190) {
2232 		/* Superblock is authoritative wrt given raid set layout! */
2233 		mddev->new_level = le32_to_cpu(sb->new_level);
2234 		mddev->new_layout = le32_to_cpu(sb->new_layout);
2235 		mddev->new_chunk_sectors = le32_to_cpu(sb->new_stripe_sectors);
2236 		mddev->delta_disks = le32_to_cpu(sb->delta_disks);
2237 		mddev->array_sectors = le64_to_cpu(sb->array_sectors);
2238 
2239 		/* raid was reshaping and got interrupted */
2240 		if (le32_to_cpu(sb->flags) & SB_FLAG_RESHAPE_ACTIVE) {
2241 			if (test_bit(__CTR_FLAG_DELTA_DISKS, &rs->ctr_flags)) {
2242 				DMERR("Reshape requested but raid set is still reshaping");
2243 				return -EINVAL;
2244 			}
2245 
2246 			if (mddev->delta_disks < 0 ||
2247 			    (!mddev->delta_disks && (le32_to_cpu(sb->flags) & SB_FLAG_RESHAPE_BACKWARDS)))
2248 				mddev->reshape_backwards = 1;
2249 			else
2250 				mddev->reshape_backwards = 0;
2251 
2252 			mddev->reshape_position = le64_to_cpu(sb->reshape_position);
2253 			rs->raid_type = get_raid_type_by_ll(mddev->level, mddev->layout);
2254 		}
2255 
2256 	} else {
2257 		/*
2258 		 * No takeover/reshaping, because we don't have the extended v1.9.0 metadata
2259 		 */
2260 		struct raid_type *rt_cur = get_raid_type_by_ll(mddev->level, mddev->layout);
2261 		struct raid_type *rt_new = get_raid_type_by_ll(mddev->new_level, mddev->new_layout);
2262 
2263 		if (rs_takeover_requested(rs)) {
2264 			if (rt_cur && rt_new)
2265 				DMERR("Takeover raid sets from %s to %s not yet supported by metadata. (raid level change)",
2266 				      rt_cur->name, rt_new->name);
2267 			else
2268 				DMERR("Takeover raid sets not yet supported by metadata. (raid level change)");
2269 			return -EINVAL;
2270 		} else if (rs_reshape_requested(rs)) {
2271 			DMERR("Reshaping raid sets not yet supported by metadata. (raid layout change keeping level)");
2272 			if (mddev->layout != mddev->new_layout) {
2273 				if (rt_cur && rt_new)
2274 					DMERR("	 current layout %s vs new layout %s",
2275 					      rt_cur->name, rt_new->name);
2276 				else
2277 					DMERR("	 current layout 0x%X vs new layout 0x%X",
2278 					      le32_to_cpu(sb->layout), mddev->new_layout);
2279 			}
2280 			if (mddev->chunk_sectors != mddev->new_chunk_sectors)
2281 				DMERR("	 current stripe sectors %u vs new stripe sectors %u",
2282 				      mddev->chunk_sectors, mddev->new_chunk_sectors);
2283 			if (rs->delta_disks)
2284 				DMERR("	 current %u disks vs new %u disks",
2285 				      mddev->raid_disks, mddev->raid_disks + rs->delta_disks);
2286 			if (rs_is_raid10(rs)) {
2287 				DMERR("	 Old layout: %s w/ %u copies",
2288 				      raid10_md_layout_to_format(mddev->layout),
2289 				      raid10_md_layout_to_copies(mddev->layout));
2290 				DMERR("	 New layout: %s w/ %u copies",
2291 				      raid10_md_layout_to_format(mddev->new_layout),
2292 				      raid10_md_layout_to_copies(mddev->new_layout));
2293 			}
2294 			return -EINVAL;
2295 		}
2296 
2297 		DMINFO("Discovered old metadata format; upgrading to extended metadata format");
2298 	}
2299 
2300 	if (!test_bit(__CTR_FLAG_NOSYNC, &rs->ctr_flags))
2301 		mddev->recovery_cp = le64_to_cpu(sb->array_resync_offset);
2302 
2303 	/*
2304 	 * During load, we set FirstUse if a new superblock was written.
2305 	 * There are two reasons we might not have a superblock:
2306 	 * 1) The raid set is brand new - in which case, all of the
2307 	 *    devices must have their In_sync bit set.	Also,
2308 	 *    recovery_cp must be 0, unless forced.
2309 	 * 2) This is a new device being added to an old raid set
2310 	 *    and the new device needs to be rebuilt - in which
2311 	 *    case the In_sync bit will /not/ be set and
2312 	 *    recovery_cp must be MaxSector.
2313 	 * 3) This is/are a new device(s) being added to an old
2314 	 *    raid set during takeover to a higher raid level
2315 	 *    to provide capacity for redundancy or during reshape
2316 	 *    to add capacity to grow the raid set.
2317 	 */
2318 	d = 0;
2319 	rdev_for_each(r, mddev) {
2320 		if (test_bit(Journal, &rdev->flags))
2321 			continue;
2322 
2323 		if (test_bit(FirstUse, &r->flags))
2324 			new_devs++;
2325 
2326 		if (!test_bit(In_sync, &r->flags)) {
2327 			DMINFO("Device %d specified for rebuild; clearing superblock",
2328 				r->raid_disk);
2329 			rebuilds++;
2330 
2331 			if (test_bit(FirstUse, &r->flags))
2332 				rebuild_and_new++;
2333 		}
2334 
2335 		d++;
2336 	}
2337 
2338 	if (new_devs == rs->raid_disks || !rebuilds) {
2339 		/* Replace a broken device */
2340 		if (new_devs == rs->raid_disks) {
2341 			DMINFO("Superblocks created for new raid set");
2342 			set_bit(MD_ARRAY_FIRST_USE, &mddev->flags);
2343 		} else if (new_devs != rebuilds &&
2344 			   new_devs != rs->delta_disks) {
2345 			DMERR("New device injected into existing raid set without "
2346 			      "'delta_disks' or 'rebuild' parameter specified");
2347 			return -EINVAL;
2348 		}
2349 	} else if (new_devs && new_devs != rebuilds) {
2350 		DMERR("%u 'rebuild' devices cannot be injected into"
2351 		      " a raid set with %u other first-time devices",
2352 		      rebuilds, new_devs);
2353 		return -EINVAL;
2354 	} else if (rebuilds) {
2355 		if (rebuild_and_new && rebuilds != rebuild_and_new) {
2356 			DMERR("new device%s provided without 'rebuild'",
2357 			      new_devs > 1 ? "s" : "");
2358 			return -EINVAL;
2359 		} else if (!test_bit(__CTR_FLAG_REBUILD, &rs->ctr_flags) && rs_is_recovering(rs)) {
2360 			DMERR("'rebuild' specified while raid set is not in-sync (recovery_cp=%llu)",
2361 			      (unsigned long long) mddev->recovery_cp);
2362 			return -EINVAL;
2363 		} else if (rs_is_reshaping(rs)) {
2364 			DMERR("'rebuild' specified while raid set is being reshaped (reshape_position=%llu)",
2365 			      (unsigned long long) mddev->reshape_position);
2366 			return -EINVAL;
2367 		}
2368 	}
2369 
2370 	/*
2371 	 * Now we set the Faulty bit for those devices that are
2372 	 * recorded in the superblock as failed.
2373 	 */
2374 	sb_retrieve_failed_devices(sb, failed_devices);
2375 	rdev_for_each(r, mddev) {
2376 		if (test_bit(Journal, &rdev->flags) ||
2377 		    !r->sb_page)
2378 			continue;
2379 		sb2 = page_address(r->sb_page);
2380 		sb2->failed_devices = 0;
2381 		memset(sb2->extended_failed_devices, 0, sizeof(sb2->extended_failed_devices));
2382 
2383 		/*
2384 		 * Check for any device re-ordering.
2385 		 */
2386 		if (!test_bit(FirstUse, &r->flags) && (r->raid_disk >= 0)) {
2387 			role = le32_to_cpu(sb2->array_position);
2388 			if (role < 0)
2389 				continue;
2390 
2391 			if (role != r->raid_disk) {
2392 				if (rs_is_raid10(rs) && __is_raid10_near(mddev->layout)) {
2393 					if (mddev->raid_disks % __raid10_near_copies(mddev->layout) ||
2394 					    rs->raid_disks % rs->raid10_copies) {
2395 						rs->ti->error =
2396 							"Cannot change raid10 near set to odd # of devices!";
2397 						return -EINVAL;
2398 					}
2399 
2400 					sb2->array_position = cpu_to_le32(r->raid_disk);
2401 
2402 				} else if (!(rs_is_raid10(rs) && rt_is_raid0(rs->raid_type)) &&
2403 					   !(rs_is_raid0(rs) && rt_is_raid10(rs->raid_type)) &&
2404 					   !rt_is_raid1(rs->raid_type)) {
2405 					rs->ti->error = "Cannot change device positions in raid set";
2406 					return -EINVAL;
2407 				}
2408 
2409 				DMINFO("raid device #%d now at position #%d", role, r->raid_disk);
2410 			}
2411 
2412 			/*
2413 			 * Partial recovery is performed on
2414 			 * returning failed devices.
2415 			 */
2416 			if (test_bit(role, (void *) failed_devices))
2417 				set_bit(Faulty, &r->flags);
2418 		}
2419 	}
2420 
2421 	return 0;
2422 }
2423 
2424 static int super_validate(struct raid_set *rs, struct md_rdev *rdev)
2425 {
2426 	struct mddev *mddev = &rs->md;
2427 	struct dm_raid_superblock *sb;
2428 
2429 	if (rs_is_raid0(rs) || !rdev->sb_page || rdev->raid_disk < 0)
2430 		return 0;
2431 
2432 	sb = page_address(rdev->sb_page);
2433 
2434 	/*
2435 	 * If mddev->events is not set, we know we have not yet initialized
2436 	 * the array.
2437 	 */
2438 	if (!mddev->events && super_init_validation(rs, rdev))
2439 		return -EINVAL;
2440 
2441 	if (le32_to_cpu(sb->compat_features) &&
2442 	    le32_to_cpu(sb->compat_features) != FEATURE_FLAG_SUPPORTS_V190) {
2443 		rs->ti->error = "Unable to assemble array: Unknown flag(s) in compatible feature flags";
2444 		return -EINVAL;
2445 	}
2446 
2447 	if (sb->incompat_features) {
2448 		rs->ti->error = "Unable to assemble array: No incompatible feature flags supported yet";
2449 		return -EINVAL;
2450 	}
2451 
2452 	/* Enable bitmap creation on @rs unless no metadevs or raid0 or journaled raid4/5/6 set. */
2453 	mddev->bitmap_info.offset = (rt_is_raid0(rs->raid_type) || rs->journal_dev.dev) ? 0 : to_sector(4096);
2454 	mddev->bitmap_info.default_offset = mddev->bitmap_info.offset;
2455 
2456 	if (!test_and_clear_bit(FirstUse, &rdev->flags)) {
2457 		/*
2458 		 * Retrieve rdev size stored in superblock to be prepared for shrink.
2459 		 * Check extended superblock members are present otherwise the size
2460 		 * will not be set!
2461 		 */
2462 		if (le32_to_cpu(sb->compat_features) & FEATURE_FLAG_SUPPORTS_V190)
2463 			rdev->sectors = le64_to_cpu(sb->sectors);
2464 
2465 		rdev->recovery_offset = le64_to_cpu(sb->disk_recovery_offset);
2466 		if (rdev->recovery_offset == MaxSector)
2467 			set_bit(In_sync, &rdev->flags);
2468 		/*
2469 		 * If no reshape in progress -> we're recovering single
2470 		 * disk(s) and have to set the device(s) to out-of-sync
2471 		 */
2472 		else if (!rs_is_reshaping(rs))
2473 			clear_bit(In_sync, &rdev->flags); /* Mandatory for recovery */
2474 	}
2475 
2476 	/*
2477 	 * If a device comes back, set it as not In_sync and no longer faulty.
2478 	 */
2479 	if (test_and_clear_bit(Faulty, &rdev->flags)) {
2480 		rdev->recovery_offset = 0;
2481 		clear_bit(In_sync, &rdev->flags);
2482 		rdev->saved_raid_disk = rdev->raid_disk;
2483 	}
2484 
2485 	/* Reshape support -> restore repective data offsets */
2486 	rdev->data_offset = le64_to_cpu(sb->data_offset);
2487 	rdev->new_data_offset = le64_to_cpu(sb->new_data_offset);
2488 
2489 	return 0;
2490 }
2491 
2492 /*
2493  * Analyse superblocks and select the freshest.
2494  */
2495 static int analyse_superblocks(struct dm_target *ti, struct raid_set *rs)
2496 {
2497 	int r;
2498 	struct md_rdev *rdev, *freshest;
2499 	struct mddev *mddev = &rs->md;
2500 
2501 	freshest = NULL;
2502 	rdev_for_each(rdev, mddev) {
2503 		if (test_bit(Journal, &rdev->flags))
2504 			continue;
2505 
2506 		if (!rdev->meta_bdev)
2507 			continue;
2508 
2509 		/* Set superblock offset/size for metadata device. */
2510 		rdev->sb_start = 0;
2511 		rdev->sb_size = bdev_logical_block_size(rdev->meta_bdev);
2512 		if (rdev->sb_size < sizeof(struct dm_raid_superblock) || rdev->sb_size > PAGE_SIZE) {
2513 			DMERR("superblock size of a logical block is no longer valid");
2514 			return -EINVAL;
2515 		}
2516 
2517 		/*
2518 		 * Skipping super_load due to CTR_FLAG_SYNC will cause
2519 		 * the array to undergo initialization again as
2520 		 * though it were new.	This is the intended effect
2521 		 * of the "sync" directive.
2522 		 *
2523 		 * With reshaping capability added, we must ensure that
2524 		 * that the "sync" directive is disallowed during the reshape.
2525 		 */
2526 		if (test_bit(__CTR_FLAG_SYNC, &rs->ctr_flags))
2527 			continue;
2528 
2529 		r = super_load(rdev, freshest);
2530 
2531 		switch (r) {
2532 		case 1:
2533 			freshest = rdev;
2534 			break;
2535 		case 0:
2536 			break;
2537 		default:
2538 			/* This is a failure to read the superblock from the metadata device. */
2539 			/*
2540 			 * We have to keep any raid0 data/metadata device pairs or
2541 			 * the MD raid0 personality will fail to start the array.
2542 			 */
2543 			if (rs_is_raid0(rs))
2544 				continue;
2545 
2546 			/*
2547 			 * We keep the dm_devs to be able to emit the device tuple
2548 			 * properly on the table line in raid_status() (rather than
2549 			 * mistakenly acting as if '- -' got passed into the constructor).
2550 			 *
2551 			 * The rdev has to stay on the same_set list to allow for
2552 			 * the attempt to restore faulty devices on second resume.
2553 			 */
2554 			rdev->raid_disk = rdev->saved_raid_disk = -1;
2555 			break;
2556 		}
2557 	}
2558 
2559 	if (!freshest)
2560 		return 0;
2561 
2562 	/*
2563 	 * Validation of the freshest device provides the source of
2564 	 * validation for the remaining devices.
2565 	 */
2566 	rs->ti->error = "Unable to assemble array: Invalid superblocks";
2567 	if (super_validate(rs, freshest))
2568 		return -EINVAL;
2569 
2570 	if (validate_raid_redundancy(rs)) {
2571 		rs->ti->error = "Insufficient redundancy to activate array";
2572 		return -EINVAL;
2573 	}
2574 
2575 	rdev_for_each(rdev, mddev)
2576 		if (!test_bit(Journal, &rdev->flags) &&
2577 		    rdev != freshest &&
2578 		    super_validate(rs, rdev))
2579 			return -EINVAL;
2580 	return 0;
2581 }
2582 
2583 /*
2584  * Adjust data_offset and new_data_offset on all disk members of @rs
2585  * for out of place reshaping if requested by contructor
2586  *
2587  * We need free space at the beginning of each raid disk for forward
2588  * and at the end for backward reshapes which userspace has to provide
2589  * via remapping/reordering of space.
2590  */
2591 static int rs_adjust_data_offsets(struct raid_set *rs)
2592 {
2593 	sector_t data_offset = 0, new_data_offset = 0;
2594 	struct md_rdev *rdev;
2595 
2596 	/* Constructor did not request data offset change */
2597 	if (!test_bit(__CTR_FLAG_DATA_OFFSET, &rs->ctr_flags)) {
2598 		if (!rs_is_reshapable(rs))
2599 			goto out;
2600 
2601 		return 0;
2602 	}
2603 
2604 	/* HM FIXME: get In_Sync raid_dev? */
2605 	rdev = &rs->dev[0].rdev;
2606 
2607 	if (rs->delta_disks < 0) {
2608 		/*
2609 		 * Removing disks (reshaping backwards):
2610 		 *
2611 		 * - before reshape: data is at offset 0 and free space
2612 		 *		     is at end of each component LV
2613 		 *
2614 		 * - after reshape: data is at offset rs->data_offset != 0 on each component LV
2615 		 */
2616 		data_offset = 0;
2617 		new_data_offset = rs->data_offset;
2618 
2619 	} else if (rs->delta_disks > 0) {
2620 		/*
2621 		 * Adding disks (reshaping forwards):
2622 		 *
2623 		 * - before reshape: data is at offset rs->data_offset != 0 and
2624 		 *		     free space is at begin of each component LV
2625 		 *
2626 		 * - after reshape: data is at offset 0 on each component LV
2627 		 */
2628 		data_offset = rs->data_offset;
2629 		new_data_offset = 0;
2630 
2631 	} else {
2632 		/*
2633 		 * User space passes in 0 for data offset after having removed reshape space
2634 		 *
2635 		 * - or - (data offset != 0)
2636 		 *
2637 		 * Changing RAID layout or chunk size -> toggle offsets
2638 		 *
2639 		 * - before reshape: data is at offset rs->data_offset 0 and
2640 		 *		     free space is at end of each component LV
2641 		 *		     -or-
2642 		 *                   data is at offset rs->data_offset != 0 and
2643 		 *		     free space is at begin of each component LV
2644 		 *
2645 		 * - after reshape: data is at offset 0 if it was at offset != 0
2646 		 *                  or at offset != 0 if it was at offset 0
2647 		 *                  on each component LV
2648 		 *
2649 		 */
2650 		data_offset = rs->data_offset ? rdev->data_offset : 0;
2651 		new_data_offset = data_offset ? 0 : rs->data_offset;
2652 		set_bit(RT_FLAG_UPDATE_SBS, &rs->runtime_flags);
2653 	}
2654 
2655 	/*
2656 	 * Make sure we got a minimum amount of free sectors per device
2657 	 */
2658 	if (rs->data_offset &&
2659 	    to_sector(i_size_read(rdev->bdev->bd_inode)) - rs->md.dev_sectors < MIN_FREE_RESHAPE_SPACE) {
2660 		rs->ti->error = data_offset ? "No space for forward reshape" :
2661 					      "No space for backward reshape";
2662 		return -ENOSPC;
2663 	}
2664 out:
2665 	/*
2666 	 * Raise recovery_cp in case data_offset != 0 to
2667 	 * avoid false recovery positives in the constructor.
2668 	 */
2669 	if (rs->md.recovery_cp < rs->md.dev_sectors)
2670 		rs->md.recovery_cp += rs->dev[0].rdev.data_offset;
2671 
2672 	/* Adjust data offsets on all rdevs but on any raid4/5/6 journal device */
2673 	rdev_for_each(rdev, &rs->md) {
2674 		if (!test_bit(Journal, &rdev->flags)) {
2675 			rdev->data_offset = data_offset;
2676 			rdev->new_data_offset = new_data_offset;
2677 		}
2678 	}
2679 
2680 	return 0;
2681 }
2682 
2683 /* Userpace reordered disks -> adjust raid_disk indexes in @rs */
2684 static void __reorder_raid_disk_indexes(struct raid_set *rs)
2685 {
2686 	int i = 0;
2687 	struct md_rdev *rdev;
2688 
2689 	rdev_for_each(rdev, &rs->md) {
2690 		if (!test_bit(Journal, &rdev->flags)) {
2691 			rdev->raid_disk = i++;
2692 			rdev->saved_raid_disk = rdev->new_raid_disk = -1;
2693 		}
2694 	}
2695 }
2696 
2697 /*
2698  * Setup @rs for takeover by a different raid level
2699  */
2700 static int rs_setup_takeover(struct raid_set *rs)
2701 {
2702 	struct mddev *mddev = &rs->md;
2703 	struct md_rdev *rdev;
2704 	unsigned int d = mddev->raid_disks = rs->raid_disks;
2705 	sector_t new_data_offset = rs->dev[0].rdev.data_offset ? 0 : rs->data_offset;
2706 
2707 	if (rt_is_raid10(rs->raid_type)) {
2708 		if (rs_is_raid0(rs)) {
2709 			/* Userpace reordered disks -> adjust raid_disk indexes */
2710 			__reorder_raid_disk_indexes(rs);
2711 
2712 			/* raid0 -> raid10_far layout */
2713 			mddev->layout = raid10_format_to_md_layout(rs, ALGORITHM_RAID10_FAR,
2714 								   rs->raid10_copies);
2715 		} else if (rs_is_raid1(rs))
2716 			/* raid1 -> raid10_near layout */
2717 			mddev->layout = raid10_format_to_md_layout(rs, ALGORITHM_RAID10_NEAR,
2718 								   rs->raid_disks);
2719 		else
2720 			return -EINVAL;
2721 
2722 	}
2723 
2724 	clear_bit(MD_ARRAY_FIRST_USE, &mddev->flags);
2725 	mddev->recovery_cp = MaxSector;
2726 
2727 	while (d--) {
2728 		rdev = &rs->dev[d].rdev;
2729 
2730 		if (test_bit(d, (void *) rs->rebuild_disks)) {
2731 			clear_bit(In_sync, &rdev->flags);
2732 			clear_bit(Faulty, &rdev->flags);
2733 			mddev->recovery_cp = rdev->recovery_offset = 0;
2734 			/* Bitmap has to be created when we do an "up" takeover */
2735 			set_bit(MD_ARRAY_FIRST_USE, &mddev->flags);
2736 		}
2737 
2738 		rdev->new_data_offset = new_data_offset;
2739 	}
2740 
2741 	return 0;
2742 }
2743 
2744 /* Prepare @rs for reshape */
2745 static int rs_prepare_reshape(struct raid_set *rs)
2746 {
2747 	bool reshape;
2748 	struct mddev *mddev = &rs->md;
2749 
2750 	if (rs_is_raid10(rs)) {
2751 		if (rs->raid_disks != mddev->raid_disks &&
2752 		    __is_raid10_near(mddev->layout) &&
2753 		    rs->raid10_copies &&
2754 		    rs->raid10_copies != __raid10_near_copies(mddev->layout)) {
2755 			/*
2756 			 * raid disk have to be multiple of data copies to allow this conversion,
2757 			 *
2758 			 * This is actually not a reshape it is a
2759 			 * rebuild of any additional mirrors per group
2760 			 */
2761 			if (rs->raid_disks % rs->raid10_copies) {
2762 				rs->ti->error = "Can't reshape raid10 mirror groups";
2763 				return -EINVAL;
2764 			}
2765 
2766 			/* Userpace reordered disks to add/remove mirrors -> adjust raid_disk indexes */
2767 			__reorder_raid_disk_indexes(rs);
2768 			mddev->layout = raid10_format_to_md_layout(rs, ALGORITHM_RAID10_NEAR,
2769 								   rs->raid10_copies);
2770 			mddev->new_layout = mddev->layout;
2771 			reshape = false;
2772 		} else
2773 			reshape = true;
2774 
2775 	} else if (rs_is_raid456(rs))
2776 		reshape = true;
2777 
2778 	else if (rs_is_raid1(rs)) {
2779 		if (rs->delta_disks) {
2780 			/* Process raid1 via delta_disks */
2781 			mddev->degraded = rs->delta_disks < 0 ? -rs->delta_disks : rs->delta_disks;
2782 			reshape = true;
2783 		} else {
2784 			/* Process raid1 without delta_disks */
2785 			mddev->raid_disks = rs->raid_disks;
2786 			reshape = false;
2787 		}
2788 	} else {
2789 		rs->ti->error = "Called with bogus raid type";
2790 		return -EINVAL;
2791 	}
2792 
2793 	if (reshape) {
2794 		set_bit(RT_FLAG_RESHAPE_RS, &rs->runtime_flags);
2795 		set_bit(RT_FLAG_UPDATE_SBS, &rs->runtime_flags);
2796 	} else if (mddev->raid_disks < rs->raid_disks)
2797 		/* Create new superblocks and bitmaps, if any new disks */
2798 		set_bit(RT_FLAG_UPDATE_SBS, &rs->runtime_flags);
2799 
2800 	return 0;
2801 }
2802 
2803 /* Get reshape sectors from data_offsets or raid set */
2804 static sector_t _get_reshape_sectors(struct raid_set *rs)
2805 {
2806 	struct md_rdev *rdev;
2807 	sector_t reshape_sectors = 0;
2808 
2809 	rdev_for_each(rdev, &rs->md)
2810 		if (!test_bit(Journal, &rdev->flags)) {
2811 			reshape_sectors = (rdev->data_offset > rdev->new_data_offset) ?
2812 					rdev->data_offset - rdev->new_data_offset :
2813 					rdev->new_data_offset - rdev->data_offset;
2814 			break;
2815 		}
2816 
2817 	return max(reshape_sectors, (sector_t) rs->data_offset);
2818 }
2819 
2820 /*
2821  *
2822  * - change raid layout
2823  * - change chunk size
2824  * - add disks
2825  * - remove disks
2826  */
2827 static int rs_setup_reshape(struct raid_set *rs)
2828 {
2829 	int r = 0;
2830 	unsigned int cur_raid_devs, d;
2831 	sector_t reshape_sectors = _get_reshape_sectors(rs);
2832 	struct mddev *mddev = &rs->md;
2833 	struct md_rdev *rdev;
2834 
2835 	mddev->delta_disks = rs->delta_disks;
2836 	cur_raid_devs = mddev->raid_disks;
2837 
2838 	/* Ignore impossible layout change whilst adding/removing disks */
2839 	if (mddev->delta_disks &&
2840 	    mddev->layout != mddev->new_layout) {
2841 		DMINFO("Ignoring invalid layout change with delta_disks=%d", rs->delta_disks);
2842 		mddev->new_layout = mddev->layout;
2843 	}
2844 
2845 	/*
2846 	 * Adjust array size:
2847 	 *
2848 	 * - in case of adding disk(s), array size has
2849 	 *   to grow after the disk adding reshape,
2850 	 *   which'll hapen in the event handler;
2851 	 *   reshape will happen forward, so space has to
2852 	 *   be available at the beginning of each disk
2853 	 *
2854 	 * - in case of removing disk(s), array size
2855 	 *   has to shrink before starting the reshape,
2856 	 *   which'll happen here;
2857 	 *   reshape will happen backward, so space has to
2858 	 *   be available at the end of each disk
2859 	 *
2860 	 * - data_offset and new_data_offset are
2861 	 *   adjusted for aforementioned out of place
2862 	 *   reshaping based on userspace passing in
2863 	 *   the "data_offset <sectors>" key/value
2864 	 *   pair via the constructor
2865 	 */
2866 
2867 	/* Add disk(s) */
2868 	if (rs->delta_disks > 0) {
2869 		/* Prepare disks for check in raid4/5/6/10 {check|start}_reshape */
2870 		for (d = cur_raid_devs; d < rs->raid_disks; d++) {
2871 			rdev = &rs->dev[d].rdev;
2872 			clear_bit(In_sync, &rdev->flags);
2873 
2874 			/*
2875 			 * save_raid_disk needs to be -1, or recovery_offset will be set to 0
2876 			 * by md, which'll store that erroneously in the superblock on reshape
2877 			 */
2878 			rdev->saved_raid_disk = -1;
2879 			rdev->raid_disk = d;
2880 
2881 			rdev->sectors = mddev->dev_sectors;
2882 			rdev->recovery_offset = rs_is_raid1(rs) ? 0 : MaxSector;
2883 		}
2884 
2885 		mddev->reshape_backwards = 0; /* adding disk(s) -> forward reshape */
2886 
2887 	/* Remove disk(s) */
2888 	} else if (rs->delta_disks < 0) {
2889 		r = rs_set_dev_and_array_sectors(rs, rs->ti->len, true);
2890 		mddev->reshape_backwards = 1; /* removing disk(s) -> backward reshape */
2891 
2892 	/* Change layout and/or chunk size */
2893 	} else {
2894 		/*
2895 		 * Reshape layout (e.g. raid5_ls -> raid5_n) and/or chunk size:
2896 		 *
2897 		 * keeping number of disks and do layout change ->
2898 		 *
2899 		 * toggle reshape_backward depending on data_offset:
2900 		 *
2901 		 * - free space upfront -> reshape forward
2902 		 *
2903 		 * - free space at the end -> reshape backward
2904 		 *
2905 		 *
2906 		 * This utilizes free reshape space avoiding the need
2907 		 * for userspace to move (parts of) LV segments in
2908 		 * case of layout/chunksize change  (for disk
2909 		 * adding/removing reshape space has to be at
2910 		 * the proper address (see above with delta_disks):
2911 		 *
2912 		 * add disk(s)   -> begin
2913 		 * remove disk(s)-> end
2914 		 */
2915 		mddev->reshape_backwards = rs->dev[0].rdev.data_offset ? 0 : 1;
2916 	}
2917 
2918 	/*
2919 	 * Adjust device size for forward reshape
2920 	 * because md_finish_reshape() reduces it.
2921 	 */
2922 	if (!mddev->reshape_backwards)
2923 		rdev_for_each(rdev, &rs->md)
2924 			if (!test_bit(Journal, &rdev->flags))
2925 				rdev->sectors += reshape_sectors;
2926 
2927 	return r;
2928 }
2929 
2930 /*
2931  * Enable/disable discard support on RAID set depending on
2932  * RAID level and discard properties of underlying RAID members.
2933  */
2934 static void configure_discard_support(struct raid_set *rs)
2935 {
2936 	int i;
2937 	bool raid456;
2938 	struct dm_target *ti = rs->ti;
2939 
2940 	/*
2941 	 * XXX: RAID level 4,5,6 require zeroing for safety.
2942 	 */
2943 	raid456 = rs_is_raid456(rs);
2944 
2945 	for (i = 0; i < rs->raid_disks; i++) {
2946 		struct request_queue *q;
2947 
2948 		if (!rs->dev[i].rdev.bdev)
2949 			continue;
2950 
2951 		q = bdev_get_queue(rs->dev[i].rdev.bdev);
2952 		if (!q || !blk_queue_discard(q))
2953 			return;
2954 
2955 		if (raid456) {
2956 			if (!devices_handle_discard_safely) {
2957 				DMERR("raid456 discard support disabled due to discard_zeroes_data uncertainty.");
2958 				DMERR("Set dm-raid.devices_handle_discard_safely=Y to override.");
2959 				return;
2960 			}
2961 		}
2962 	}
2963 
2964 	ti->num_discard_bios = 1;
2965 }
2966 
2967 /*
2968  * Construct a RAID0/1/10/4/5/6 mapping:
2969  * Args:
2970  *	<raid_type> <#raid_params> <raid_params>{0,}	\
2971  *	<#raid_devs> [<meta_dev1> <dev1>]{1,}
2972  *
2973  * <raid_params> varies by <raid_type>.	 See 'parse_raid_params' for
2974  * details on possible <raid_params>.
2975  *
2976  * Userspace is free to initialize the metadata devices, hence the superblocks to
2977  * enforce recreation based on the passed in table parameters.
2978  *
2979  */
2980 static int raid_ctr(struct dm_target *ti, unsigned int argc, char **argv)
2981 {
2982 	int r;
2983 	bool resize = false;
2984 	struct raid_type *rt;
2985 	unsigned int num_raid_params, num_raid_devs;
2986 	sector_t sb_array_sectors, rdev_sectors, reshape_sectors;
2987 	struct raid_set *rs = NULL;
2988 	const char *arg;
2989 	struct rs_layout rs_layout;
2990 	struct dm_arg_set as = { argc, argv }, as_nrd;
2991 	struct dm_arg _args[] = {
2992 		{ 0, as.argc, "Cannot understand number of raid parameters" },
2993 		{ 1, 254, "Cannot understand number of raid devices parameters" }
2994 	};
2995 
2996 	arg = dm_shift_arg(&as);
2997 	if (!arg) {
2998 		ti->error = "No arguments";
2999 		return -EINVAL;
3000 	}
3001 
3002 	rt = get_raid_type(arg);
3003 	if (!rt) {
3004 		ti->error = "Unrecognised raid_type";
3005 		return -EINVAL;
3006 	}
3007 
3008 	/* Must have <#raid_params> */
3009 	if (dm_read_arg_group(_args, &as, &num_raid_params, &ti->error))
3010 		return -EINVAL;
3011 
3012 	/* number of raid device tupples <meta_dev data_dev> */
3013 	as_nrd = as;
3014 	dm_consume_args(&as_nrd, num_raid_params);
3015 	_args[1].max = (as_nrd.argc - 1) / 2;
3016 	if (dm_read_arg(_args + 1, &as_nrd, &num_raid_devs, &ti->error))
3017 		return -EINVAL;
3018 
3019 	if (!__within_range(num_raid_devs, 1, MAX_RAID_DEVICES)) {
3020 		ti->error = "Invalid number of supplied raid devices";
3021 		return -EINVAL;
3022 	}
3023 
3024 	rs = raid_set_alloc(ti, rt, num_raid_devs);
3025 	if (IS_ERR(rs))
3026 		return PTR_ERR(rs);
3027 
3028 	r = parse_raid_params(rs, &as, num_raid_params);
3029 	if (r)
3030 		goto bad;
3031 
3032 	r = parse_dev_params(rs, &as);
3033 	if (r)
3034 		goto bad;
3035 
3036 	rs->md.sync_super = super_sync;
3037 
3038 	/*
3039 	 * Calculate ctr requested array and device sizes to allow
3040 	 * for superblock analysis needing device sizes defined.
3041 	 *
3042 	 * Any existing superblock will overwrite the array and device sizes
3043 	 */
3044 	r = rs_set_dev_and_array_sectors(rs, rs->ti->len, false);
3045 	if (r)
3046 		goto bad;
3047 
3048 	/* Memorize just calculated, potentially larger sizes to grow the raid set in preresume */
3049 	rs->array_sectors = rs->md.array_sectors;
3050 	rs->dev_sectors = rs->md.dev_sectors;
3051 
3052 	/*
3053 	 * Backup any new raid set level, layout, ...
3054 	 * requested to be able to compare to superblock
3055 	 * members for conversion decisions.
3056 	 */
3057 	rs_config_backup(rs, &rs_layout);
3058 
3059 	r = analyse_superblocks(ti, rs);
3060 	if (r)
3061 		goto bad;
3062 
3063 	/* All in-core metadata now as of current superblocks after calling analyse_superblocks() */
3064 	sb_array_sectors = rs->md.array_sectors;
3065 	rdev_sectors = __rdev_sectors(rs);
3066 	if (!rdev_sectors) {
3067 		ti->error = "Invalid rdev size";
3068 		r = -EINVAL;
3069 		goto bad;
3070 	}
3071 
3072 
3073 	reshape_sectors = _get_reshape_sectors(rs);
3074 	if (rs->dev_sectors != rdev_sectors) {
3075 		resize = (rs->dev_sectors != rdev_sectors - reshape_sectors);
3076 		if (rs->dev_sectors > rdev_sectors - reshape_sectors)
3077 			set_bit(RT_FLAG_RS_GROW, &rs->runtime_flags);
3078 	}
3079 
3080 	INIT_WORK(&rs->md.event_work, do_table_event);
3081 	ti->private = rs;
3082 	ti->num_flush_bios = 1;
3083 
3084 	/* Restore any requested new layout for conversion decision */
3085 	rs_config_restore(rs, &rs_layout);
3086 
3087 	/*
3088 	 * Now that we have any superblock metadata available,
3089 	 * check for new, recovering, reshaping, to be taken over,
3090 	 * to be reshaped or an existing, unchanged raid set to
3091 	 * run in sequence.
3092 	 */
3093 	if (test_bit(MD_ARRAY_FIRST_USE, &rs->md.flags)) {
3094 		/* A new raid6 set has to be recovered to ensure proper parity and Q-Syndrome */
3095 		if (rs_is_raid6(rs) &&
3096 		    test_bit(__CTR_FLAG_NOSYNC, &rs->ctr_flags)) {
3097 			ti->error = "'nosync' not allowed for new raid6 set";
3098 			r = -EINVAL;
3099 			goto bad;
3100 		}
3101 		rs_setup_recovery(rs, 0);
3102 		set_bit(RT_FLAG_UPDATE_SBS, &rs->runtime_flags);
3103 		rs_set_new(rs);
3104 	} else if (rs_is_recovering(rs)) {
3105 		/* A recovering raid set may be resized */
3106 		goto size_check;
3107 	} else if (rs_is_reshaping(rs)) {
3108 		/* Have to reject size change request during reshape */
3109 		if (resize) {
3110 			ti->error = "Can't resize a reshaping raid set";
3111 			r = -EPERM;
3112 			goto bad;
3113 		}
3114 		/* skip setup rs */
3115 	} else if (rs_takeover_requested(rs)) {
3116 		if (rs_is_reshaping(rs)) {
3117 			ti->error = "Can't takeover a reshaping raid set";
3118 			r = -EPERM;
3119 			goto bad;
3120 		}
3121 
3122 		/* We can't takeover a journaled raid4/5/6 */
3123 		if (test_bit(__CTR_FLAG_JOURNAL_DEV, &rs->ctr_flags)) {
3124 			ti->error = "Can't takeover a journaled raid4/5/6 set";
3125 			r = -EPERM;
3126 			goto bad;
3127 		}
3128 
3129 		/*
3130 		 * If a takeover is needed, userspace sets any additional
3131 		 * devices to rebuild and we can check for a valid request here.
3132 		 *
3133 		 * If acceptible, set the level to the new requested
3134 		 * one, prohibit requesting recovery, allow the raid
3135 		 * set to run and store superblocks during resume.
3136 		 */
3137 		r = rs_check_takeover(rs);
3138 		if (r)
3139 			goto bad;
3140 
3141 		r = rs_setup_takeover(rs);
3142 		if (r)
3143 			goto bad;
3144 
3145 		set_bit(RT_FLAG_UPDATE_SBS, &rs->runtime_flags);
3146 		/* Takeover ain't recovery, so disable recovery */
3147 		rs_setup_recovery(rs, MaxSector);
3148 		rs_set_new(rs);
3149 	} else if (rs_reshape_requested(rs)) {
3150 		/* Only request grow on raid set size extensions, not on reshapes. */
3151 		clear_bit(RT_FLAG_RS_GROW, &rs->runtime_flags);
3152 
3153 		/*
3154 		 * No need to check for 'ongoing' takeover here, because takeover
3155 		 * is an instant operation as oposed to an ongoing reshape.
3156 		 */
3157 
3158 		/* We can't reshape a journaled raid4/5/6 */
3159 		if (test_bit(__CTR_FLAG_JOURNAL_DEV, &rs->ctr_flags)) {
3160 			ti->error = "Can't reshape a journaled raid4/5/6 set";
3161 			r = -EPERM;
3162 			goto bad;
3163 		}
3164 
3165 		/* Out-of-place space has to be available to allow for a reshape unless raid1! */
3166 		if (reshape_sectors || rs_is_raid1(rs)) {
3167 			/*
3168 			  * We can only prepare for a reshape here, because the
3169 			  * raid set needs to run to provide the repective reshape
3170 			  * check functions via its MD personality instance.
3171 			  *
3172 			  * So do the reshape check after md_run() succeeded.
3173 			  */
3174 			r = rs_prepare_reshape(rs);
3175 			if (r)
3176 				goto bad;
3177 
3178 			/* Reshaping ain't recovery, so disable recovery */
3179 			rs_setup_recovery(rs, MaxSector);
3180 		}
3181 		rs_set_cur(rs);
3182 	} else {
3183 size_check:
3184 		/* May not set recovery when a device rebuild is requested */
3185 		if (test_bit(__CTR_FLAG_REBUILD, &rs->ctr_flags)) {
3186 			clear_bit(RT_FLAG_RS_GROW, &rs->runtime_flags);
3187 			set_bit(RT_FLAG_UPDATE_SBS, &rs->runtime_flags);
3188 			rs_setup_recovery(rs, MaxSector);
3189 		} else if (test_bit(RT_FLAG_RS_GROW, &rs->runtime_flags)) {
3190 			/*
3191 			 * Set raid set to current size, i.e. size as of
3192 			 * superblocks to grow to larger size in preresume.
3193 			 */
3194 			r = rs_set_dev_and_array_sectors(rs, sb_array_sectors, false);
3195 			if (r)
3196 				goto bad;
3197 
3198 			rs_setup_recovery(rs, rs->md.recovery_cp < rs->md.dev_sectors ? rs->md.recovery_cp : rs->md.dev_sectors);
3199 		} else {
3200 			/* This is no size change or it is shrinking, update size and record in superblocks */
3201 			r = rs_set_dev_and_array_sectors(rs, rs->ti->len, false);
3202 			if (r)
3203 				goto bad;
3204 
3205 			if (sb_array_sectors > rs->array_sectors)
3206 				set_bit(RT_FLAG_UPDATE_SBS, &rs->runtime_flags);
3207 		}
3208 		rs_set_cur(rs);
3209 	}
3210 
3211 	/* If constructor requested it, change data and new_data offsets */
3212 	r = rs_adjust_data_offsets(rs);
3213 	if (r)
3214 		goto bad;
3215 
3216 	/* Start raid set read-only and assumed clean to change in raid_resume() */
3217 	rs->md.ro = 1;
3218 	rs->md.in_sync = 1;
3219 
3220 	/* Keep array frozen */
3221 	set_bit(MD_RECOVERY_FROZEN, &rs->md.recovery);
3222 
3223 	/* Has to be held on running the array */
3224 	mddev_lock_nointr(&rs->md);
3225 	r = md_run(&rs->md);
3226 	rs->md.in_sync = 0; /* Assume already marked dirty */
3227 	if (r) {
3228 		ti->error = "Failed to run raid array";
3229 		mddev_unlock(&rs->md);
3230 		goto bad;
3231 	}
3232 
3233 	r = md_start(&rs->md);
3234 
3235 	if (r) {
3236 		ti->error = "Failed to start raid array";
3237 		mddev_unlock(&rs->md);
3238 		goto bad_md_start;
3239 	}
3240 
3241 	/* If raid4/5/6 journal mode explicitly requested (only possible with journal dev) -> set it */
3242 	if (test_bit(__CTR_FLAG_JOURNAL_MODE, &rs->ctr_flags)) {
3243 		r = r5c_journal_mode_set(&rs->md, rs->journal_dev.mode);
3244 		if (r) {
3245 			ti->error = "Failed to set raid4/5/6 journal mode";
3246 			mddev_unlock(&rs->md);
3247 			goto bad_journal_mode_set;
3248 		}
3249 	}
3250 
3251 	mddev_suspend(&rs->md);
3252 	set_bit(RT_FLAG_RS_SUSPENDED, &rs->runtime_flags);
3253 
3254 	/* Try to adjust the raid4/5/6 stripe cache size to the stripe size */
3255 	if (rs_is_raid456(rs)) {
3256 		r = rs_set_raid456_stripe_cache(rs);
3257 		if (r)
3258 			goto bad_stripe_cache;
3259 	}
3260 
3261 	/* Now do an early reshape check */
3262 	if (test_bit(RT_FLAG_RESHAPE_RS, &rs->runtime_flags)) {
3263 		r = rs_check_reshape(rs);
3264 		if (r)
3265 			goto bad_check_reshape;
3266 
3267 		/* Restore new, ctr requested layout to perform check */
3268 		rs_config_restore(rs, &rs_layout);
3269 
3270 		if (rs->md.pers->start_reshape) {
3271 			r = rs->md.pers->check_reshape(&rs->md);
3272 			if (r) {
3273 				ti->error = "Reshape check failed";
3274 				goto bad_check_reshape;
3275 			}
3276 		}
3277 	}
3278 
3279 	/* Disable/enable discard support on raid set. */
3280 	configure_discard_support(rs);
3281 
3282 	mddev_unlock(&rs->md);
3283 	return 0;
3284 
3285 bad_md_start:
3286 bad_journal_mode_set:
3287 bad_stripe_cache:
3288 bad_check_reshape:
3289 	md_stop(&rs->md);
3290 bad:
3291 	raid_set_free(rs);
3292 
3293 	return r;
3294 }
3295 
3296 static void raid_dtr(struct dm_target *ti)
3297 {
3298 	struct raid_set *rs = ti->private;
3299 
3300 	md_stop(&rs->md);
3301 	raid_set_free(rs);
3302 }
3303 
3304 static int raid_map(struct dm_target *ti, struct bio *bio)
3305 {
3306 	struct raid_set *rs = ti->private;
3307 	struct mddev *mddev = &rs->md;
3308 
3309 	/*
3310 	 * If we're reshaping to add disk(s)), ti->len and
3311 	 * mddev->array_sectors will differ during the process
3312 	 * (ti->len > mddev->array_sectors), so we have to requeue
3313 	 * bios with addresses > mddev->array_sectors here or
3314 	 * there will occur accesses past EOD of the component
3315 	 * data images thus erroring the raid set.
3316 	 */
3317 	if (unlikely(bio_end_sector(bio) > mddev->array_sectors))
3318 		return DM_MAPIO_REQUEUE;
3319 
3320 	md_handle_request(mddev, bio);
3321 
3322 	return DM_MAPIO_SUBMITTED;
3323 }
3324 
3325 /* Return sync state string for @state */
3326 enum sync_state { st_frozen, st_reshape, st_resync, st_check, st_repair, st_recover, st_idle };
3327 static const char *sync_str(enum sync_state state)
3328 {
3329 	/* Has to be in above sync_state order! */
3330 	static const char *sync_strs[] = {
3331 		"frozen",
3332 		"reshape",
3333 		"resync",
3334 		"check",
3335 		"repair",
3336 		"recover",
3337 		"idle"
3338 	};
3339 
3340 	return __within_range(state, 0, ARRAY_SIZE(sync_strs) - 1) ? sync_strs[state] : "undef";
3341 };
3342 
3343 /* Return enum sync_state for @mddev derived from @recovery flags */
3344 static enum sync_state decipher_sync_action(struct mddev *mddev, unsigned long recovery)
3345 {
3346 	if (test_bit(MD_RECOVERY_FROZEN, &recovery))
3347 		return st_frozen;
3348 
3349 	/* The MD sync thread can be done with io or be interrupted but still be running */
3350 	if (!test_bit(MD_RECOVERY_DONE, &recovery) &&
3351 	    (test_bit(MD_RECOVERY_RUNNING, &recovery) ||
3352 	     (!mddev->ro && test_bit(MD_RECOVERY_NEEDED, &recovery)))) {
3353 		if (test_bit(MD_RECOVERY_RESHAPE, &recovery))
3354 			return st_reshape;
3355 
3356 		if (test_bit(MD_RECOVERY_SYNC, &recovery)) {
3357 			if (!test_bit(MD_RECOVERY_REQUESTED, &recovery))
3358 				return st_resync;
3359 			if (test_bit(MD_RECOVERY_CHECK, &recovery))
3360 				return st_check;
3361 			return st_repair;
3362 		}
3363 
3364 		if (test_bit(MD_RECOVERY_RECOVER, &recovery))
3365 			return st_recover;
3366 
3367 		if (mddev->reshape_position != MaxSector)
3368 			return st_reshape;
3369 	}
3370 
3371 	return st_idle;
3372 }
3373 
3374 /*
3375  * Return status string for @rdev
3376  *
3377  * Status characters:
3378  *
3379  *  'D' = Dead/Failed raid set component or raid4/5/6 journal device
3380  *  'a' = Alive but not in-sync raid set component _or_ alive raid4/5/6 'write_back' journal device
3381  *  'A' = Alive and in-sync raid set component _or_ alive raid4/5/6 'write_through' journal device
3382  *  '-' = Non-existing device (i.e. uspace passed '- -' into the ctr)
3383  */
3384 static const char *__raid_dev_status(struct raid_set *rs, struct md_rdev *rdev)
3385 {
3386 	if (!rdev->bdev)
3387 		return "-";
3388 	else if (test_bit(Faulty, &rdev->flags))
3389 		return "D";
3390 	else if (test_bit(Journal, &rdev->flags))
3391 		return (rs->journal_dev.mode == R5C_JOURNAL_MODE_WRITE_THROUGH) ? "A" : "a";
3392 	else if (test_bit(RT_FLAG_RS_RESYNCING, &rs->runtime_flags) ||
3393 		 (!test_bit(RT_FLAG_RS_IN_SYNC, &rs->runtime_flags) &&
3394 		  !test_bit(In_sync, &rdev->flags)))
3395 		return "a";
3396 	else
3397 		return "A";
3398 }
3399 
3400 /* Helper to return resync/reshape progress for @rs and runtime flags for raid set in sync / resynching */
3401 static sector_t rs_get_progress(struct raid_set *rs, unsigned long recovery,
3402 				enum sync_state state, sector_t resync_max_sectors)
3403 {
3404 	sector_t r;
3405 	struct mddev *mddev = &rs->md;
3406 
3407 	clear_bit(RT_FLAG_RS_IN_SYNC, &rs->runtime_flags);
3408 	clear_bit(RT_FLAG_RS_RESYNCING, &rs->runtime_flags);
3409 
3410 	if (rs_is_raid0(rs)) {
3411 		r = resync_max_sectors;
3412 		set_bit(RT_FLAG_RS_IN_SYNC, &rs->runtime_flags);
3413 
3414 	} else {
3415 		if (state == st_idle && !test_bit(MD_RECOVERY_INTR, &recovery))
3416 			r = mddev->recovery_cp;
3417 		else
3418 			r = mddev->curr_resync_completed;
3419 
3420 		if (state == st_idle && r >= resync_max_sectors) {
3421 			/*
3422 			 * Sync complete.
3423 			 */
3424 			/* In case we have finished recovering, the array is in sync. */
3425 			if (test_bit(MD_RECOVERY_RECOVER, &recovery))
3426 				set_bit(RT_FLAG_RS_IN_SYNC, &rs->runtime_flags);
3427 
3428 		} else if (state == st_recover)
3429 			/*
3430 			 * In case we are recovering, the array is not in sync
3431 			 * and health chars should show the recovering legs.
3432 			 *
3433 			 * Already retrieved recovery offset from curr_resync_completed above.
3434 			 */
3435 			;
3436 
3437 		else if (state == st_resync || state == st_reshape)
3438 			/*
3439 			 * If "resync/reshape" is occurring, the raid set
3440 			 * is or may be out of sync hence the health
3441 			 * characters shall be 'a'.
3442 			 */
3443 			set_bit(RT_FLAG_RS_RESYNCING, &rs->runtime_flags);
3444 
3445 		else if (state == st_check || state == st_repair)
3446 			/*
3447 			 * If "check" or "repair" is occurring, the raid set has
3448 			 * undergone an initial sync and the health characters
3449 			 * should not be 'a' anymore.
3450 			 */
3451 			set_bit(RT_FLAG_RS_IN_SYNC, &rs->runtime_flags);
3452 
3453 		else if (test_bit(MD_RECOVERY_NEEDED, &recovery))
3454 			/*
3455 			 * We are idle and recovery is needed, prevent 'A' chars race
3456 			 * caused by components still set to in-sync by constructor.
3457 			 */
3458 			set_bit(RT_FLAG_RS_RESYNCING, &rs->runtime_flags);
3459 
3460 		else {
3461 			/*
3462 			 * We are idle and the raid set may be doing an initial
3463 			 * sync, or it may be rebuilding individual components.
3464 			 * If all the devices are In_sync, then it is the raid set
3465 			 * that is being initialized.
3466 			 */
3467 			struct md_rdev *rdev;
3468 
3469 			set_bit(RT_FLAG_RS_IN_SYNC, &rs->runtime_flags);
3470 			rdev_for_each(rdev, mddev)
3471 				if (!test_bit(Journal, &rdev->flags) &&
3472 				    !test_bit(In_sync, &rdev->flags)) {
3473 					clear_bit(RT_FLAG_RS_IN_SYNC, &rs->runtime_flags);
3474 					break;
3475 				}
3476 		}
3477 	}
3478 
3479 	return min(r, resync_max_sectors);
3480 }
3481 
3482 /* Helper to return @dev name or "-" if !@dev */
3483 static const char *__get_dev_name(struct dm_dev *dev)
3484 {
3485 	return dev ? dev->name : "-";
3486 }
3487 
3488 static void raid_status(struct dm_target *ti, status_type_t type,
3489 			unsigned int status_flags, char *result, unsigned int maxlen)
3490 {
3491 	struct raid_set *rs = ti->private;
3492 	struct mddev *mddev = &rs->md;
3493 	struct r5conf *conf = mddev->private;
3494 	int i, max_nr_stripes = conf ? conf->max_nr_stripes : 0;
3495 	unsigned long recovery;
3496 	unsigned int raid_param_cnt = 1; /* at least 1 for chunksize */
3497 	unsigned int sz = 0;
3498 	unsigned int rebuild_writemostly_count = 0;
3499 	sector_t progress, resync_max_sectors, resync_mismatches;
3500 	enum sync_state state;
3501 	struct raid_type *rt;
3502 
3503 	switch (type) {
3504 	case STATUSTYPE_INFO:
3505 		/* *Should* always succeed */
3506 		rt = get_raid_type_by_ll(mddev->new_level, mddev->new_layout);
3507 		if (!rt)
3508 			return;
3509 
3510 		DMEMIT("%s %d ", rt->name, mddev->raid_disks);
3511 
3512 		/* Access most recent mddev properties for status output */
3513 		smp_rmb();
3514 		/* Get sensible max sectors even if raid set not yet started */
3515 		resync_max_sectors = test_bit(RT_FLAG_RS_PRERESUMED, &rs->runtime_flags) ?
3516 				      mddev->resync_max_sectors : mddev->dev_sectors;
3517 		recovery = rs->md.recovery;
3518 		state = decipher_sync_action(mddev, recovery);
3519 		progress = rs_get_progress(rs, recovery, state, resync_max_sectors);
3520 		resync_mismatches = (mddev->last_sync_action && !strcasecmp(mddev->last_sync_action, "check")) ?
3521 				    atomic64_read(&mddev->resync_mismatches) : 0;
3522 
3523 		/* HM FIXME: do we want another state char for raid0? It shows 'D'/'A'/'-' now */
3524 		for (i = 0; i < rs->raid_disks; i++)
3525 			DMEMIT(__raid_dev_status(rs, &rs->dev[i].rdev));
3526 
3527 		/*
3528 		 * In-sync/Reshape ratio:
3529 		 *  The in-sync ratio shows the progress of:
3530 		 *   - Initializing the raid set
3531 		 *   - Rebuilding a subset of devices of the raid set
3532 		 *  The user can distinguish between the two by referring
3533 		 *  to the status characters.
3534 		 *
3535 		 *  The reshape ratio shows the progress of
3536 		 *  changing the raid layout or the number of
3537 		 *  disks of a raid set
3538 		 */
3539 		DMEMIT(" %llu/%llu", (unsigned long long) progress,
3540 				     (unsigned long long) resync_max_sectors);
3541 
3542 		/*
3543 		 * v1.5.0+:
3544 		 *
3545 		 * Sync action:
3546 		 *   See Documentation/admin-guide/device-mapper/dm-raid.rst for
3547 		 *   information on each of these states.
3548 		 */
3549 		DMEMIT(" %s", sync_str(state));
3550 
3551 		/*
3552 		 * v1.5.0+:
3553 		 *
3554 		 * resync_mismatches/mismatch_cnt
3555 		 *   This field shows the number of discrepancies found when
3556 		 *   performing a "check" of the raid set.
3557 		 */
3558 		DMEMIT(" %llu", (unsigned long long) resync_mismatches);
3559 
3560 		/*
3561 		 * v1.9.0+:
3562 		 *
3563 		 * data_offset (needed for out of space reshaping)
3564 		 *   This field shows the data offset into the data
3565 		 *   image LV where the first stripes data starts.
3566 		 *
3567 		 * We keep data_offset equal on all raid disks of the set,
3568 		 * so retrieving it from the first raid disk is sufficient.
3569 		 */
3570 		DMEMIT(" %llu", (unsigned long long) rs->dev[0].rdev.data_offset);
3571 
3572 		/*
3573 		 * v1.10.0+:
3574 		 */
3575 		DMEMIT(" %s", test_bit(__CTR_FLAG_JOURNAL_DEV, &rs->ctr_flags) ?
3576 			      __raid_dev_status(rs, &rs->journal_dev.rdev) : "-");
3577 		break;
3578 
3579 	case STATUSTYPE_TABLE:
3580 		/* Report the table line string you would use to construct this raid set */
3581 
3582 		/*
3583 		 * Count any rebuild or writemostly argument pairs and subtract the
3584 		 * hweight count being added below of any rebuild and writemostly ctr flags.
3585 		 */
3586 		for (i = 0; i < rs->raid_disks; i++) {
3587 			rebuild_writemostly_count += (test_bit(i, (void *) rs->rebuild_disks) ? 2 : 0) +
3588 						     (test_bit(WriteMostly, &rs->dev[i].rdev.flags) ? 2 : 0);
3589 		}
3590 		rebuild_writemostly_count -= (test_bit(__CTR_FLAG_REBUILD, &rs->ctr_flags) ? 2 : 0) +
3591 					     (test_bit(__CTR_FLAG_WRITE_MOSTLY, &rs->ctr_flags) ? 2 : 0);
3592 		/* Calculate raid parameter count based on ^ rebuild/writemostly argument counts and ctr flags set. */
3593 		raid_param_cnt += rebuild_writemostly_count +
3594 				  hweight32(rs->ctr_flags & CTR_FLAG_OPTIONS_NO_ARGS) +
3595 				  hweight32(rs->ctr_flags & CTR_FLAG_OPTIONS_ONE_ARG) * 2;
3596 		/* Emit table line */
3597 		/* This has to be in the documented order for userspace! */
3598 		DMEMIT("%s %u %u", rs->raid_type->name, raid_param_cnt, mddev->new_chunk_sectors);
3599 		if (test_bit(__CTR_FLAG_SYNC, &rs->ctr_flags))
3600 			DMEMIT(" %s", dm_raid_arg_name_by_flag(CTR_FLAG_SYNC));
3601 		if (test_bit(__CTR_FLAG_NOSYNC, &rs->ctr_flags))
3602 			DMEMIT(" %s", dm_raid_arg_name_by_flag(CTR_FLAG_NOSYNC));
3603 		if (test_bit(__CTR_FLAG_REBUILD, &rs->ctr_flags))
3604 			for (i = 0; i < rs->raid_disks; i++)
3605 				if (test_bit(i, (void *) rs->rebuild_disks))
3606 					DMEMIT(" %s %u", dm_raid_arg_name_by_flag(CTR_FLAG_REBUILD), i);
3607 		if (test_bit(__CTR_FLAG_DAEMON_SLEEP, &rs->ctr_flags))
3608 			DMEMIT(" %s %lu", dm_raid_arg_name_by_flag(CTR_FLAG_DAEMON_SLEEP),
3609 					  mddev->bitmap_info.daemon_sleep);
3610 		if (test_bit(__CTR_FLAG_MIN_RECOVERY_RATE, &rs->ctr_flags))
3611 			DMEMIT(" %s %d", dm_raid_arg_name_by_flag(CTR_FLAG_MIN_RECOVERY_RATE),
3612 					 mddev->sync_speed_min);
3613 		if (test_bit(__CTR_FLAG_MAX_RECOVERY_RATE, &rs->ctr_flags))
3614 			DMEMIT(" %s %d", dm_raid_arg_name_by_flag(CTR_FLAG_MAX_RECOVERY_RATE),
3615 					 mddev->sync_speed_max);
3616 		if (test_bit(__CTR_FLAG_WRITE_MOSTLY, &rs->ctr_flags))
3617 			for (i = 0; i < rs->raid_disks; i++)
3618 				if (test_bit(WriteMostly, &rs->dev[i].rdev.flags))
3619 					DMEMIT(" %s %d", dm_raid_arg_name_by_flag(CTR_FLAG_WRITE_MOSTLY),
3620 					       rs->dev[i].rdev.raid_disk);
3621 		if (test_bit(__CTR_FLAG_MAX_WRITE_BEHIND, &rs->ctr_flags))
3622 			DMEMIT(" %s %lu", dm_raid_arg_name_by_flag(CTR_FLAG_MAX_WRITE_BEHIND),
3623 					  mddev->bitmap_info.max_write_behind);
3624 		if (test_bit(__CTR_FLAG_STRIPE_CACHE, &rs->ctr_flags))
3625 			DMEMIT(" %s %d", dm_raid_arg_name_by_flag(CTR_FLAG_STRIPE_CACHE),
3626 					 max_nr_stripes);
3627 		if (test_bit(__CTR_FLAG_REGION_SIZE, &rs->ctr_flags))
3628 			DMEMIT(" %s %llu", dm_raid_arg_name_by_flag(CTR_FLAG_REGION_SIZE),
3629 					   (unsigned long long) to_sector(mddev->bitmap_info.chunksize));
3630 		if (test_bit(__CTR_FLAG_RAID10_COPIES, &rs->ctr_flags))
3631 			DMEMIT(" %s %d", dm_raid_arg_name_by_flag(CTR_FLAG_RAID10_COPIES),
3632 					 raid10_md_layout_to_copies(mddev->layout));
3633 		if (test_bit(__CTR_FLAG_RAID10_FORMAT, &rs->ctr_flags))
3634 			DMEMIT(" %s %s", dm_raid_arg_name_by_flag(CTR_FLAG_RAID10_FORMAT),
3635 					 raid10_md_layout_to_format(mddev->layout));
3636 		if (test_bit(__CTR_FLAG_DELTA_DISKS, &rs->ctr_flags))
3637 			DMEMIT(" %s %d", dm_raid_arg_name_by_flag(CTR_FLAG_DELTA_DISKS),
3638 					 max(rs->delta_disks, mddev->delta_disks));
3639 		if (test_bit(__CTR_FLAG_DATA_OFFSET, &rs->ctr_flags))
3640 			DMEMIT(" %s %llu", dm_raid_arg_name_by_flag(CTR_FLAG_DATA_OFFSET),
3641 					   (unsigned long long) rs->data_offset);
3642 		if (test_bit(__CTR_FLAG_JOURNAL_DEV, &rs->ctr_flags))
3643 			DMEMIT(" %s %s", dm_raid_arg_name_by_flag(CTR_FLAG_JOURNAL_DEV),
3644 					__get_dev_name(rs->journal_dev.dev));
3645 		if (test_bit(__CTR_FLAG_JOURNAL_MODE, &rs->ctr_flags))
3646 			DMEMIT(" %s %s", dm_raid_arg_name_by_flag(CTR_FLAG_JOURNAL_MODE),
3647 					 md_journal_mode_to_dm_raid(rs->journal_dev.mode));
3648 		DMEMIT(" %d", rs->raid_disks);
3649 		for (i = 0; i < rs->raid_disks; i++)
3650 			DMEMIT(" %s %s", __get_dev_name(rs->dev[i].meta_dev),
3651 					 __get_dev_name(rs->dev[i].data_dev));
3652 	}
3653 }
3654 
3655 static int raid_message(struct dm_target *ti, unsigned int argc, char **argv,
3656 			char *result, unsigned maxlen)
3657 {
3658 	struct raid_set *rs = ti->private;
3659 	struct mddev *mddev = &rs->md;
3660 
3661 	if (!mddev->pers || !mddev->pers->sync_request)
3662 		return -EINVAL;
3663 
3664 	if (!strcasecmp(argv[0], "frozen"))
3665 		set_bit(MD_RECOVERY_FROZEN, &mddev->recovery);
3666 	else
3667 		clear_bit(MD_RECOVERY_FROZEN, &mddev->recovery);
3668 
3669 	if (!strcasecmp(argv[0], "idle") || !strcasecmp(argv[0], "frozen")) {
3670 		if (mddev->sync_thread) {
3671 			set_bit(MD_RECOVERY_INTR, &mddev->recovery);
3672 			md_reap_sync_thread(mddev);
3673 		}
3674 	} else if (decipher_sync_action(mddev, mddev->recovery) != st_idle)
3675 		return -EBUSY;
3676 	else if (!strcasecmp(argv[0], "resync"))
3677 		; /* MD_RECOVERY_NEEDED set below */
3678 	else if (!strcasecmp(argv[0], "recover"))
3679 		set_bit(MD_RECOVERY_RECOVER, &mddev->recovery);
3680 	else {
3681 		if (!strcasecmp(argv[0], "check")) {
3682 			set_bit(MD_RECOVERY_CHECK, &mddev->recovery);
3683 			set_bit(MD_RECOVERY_REQUESTED, &mddev->recovery);
3684 			set_bit(MD_RECOVERY_SYNC, &mddev->recovery);
3685 		} else if (!strcasecmp(argv[0], "repair")) {
3686 			set_bit(MD_RECOVERY_REQUESTED, &mddev->recovery);
3687 			set_bit(MD_RECOVERY_SYNC, &mddev->recovery);
3688 		} else
3689 			return -EINVAL;
3690 	}
3691 	if (mddev->ro == 2) {
3692 		/* A write to sync_action is enough to justify
3693 		 * canceling read-auto mode
3694 		 */
3695 		mddev->ro = 0;
3696 		if (!mddev->suspended && mddev->sync_thread)
3697 			md_wakeup_thread(mddev->sync_thread);
3698 	}
3699 	set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
3700 	if (!mddev->suspended && mddev->thread)
3701 		md_wakeup_thread(mddev->thread);
3702 
3703 	return 0;
3704 }
3705 
3706 static int raid_iterate_devices(struct dm_target *ti,
3707 				iterate_devices_callout_fn fn, void *data)
3708 {
3709 	struct raid_set *rs = ti->private;
3710 	unsigned int i;
3711 	int r = 0;
3712 
3713 	for (i = 0; !r && i < rs->md.raid_disks; i++)
3714 		if (rs->dev[i].data_dev)
3715 			r = fn(ti,
3716 				 rs->dev[i].data_dev,
3717 				 0, /* No offset on data devs */
3718 				 rs->md.dev_sectors,
3719 				 data);
3720 
3721 	return r;
3722 }
3723 
3724 static void raid_io_hints(struct dm_target *ti, struct queue_limits *limits)
3725 {
3726 	struct raid_set *rs = ti->private;
3727 	unsigned int chunk_size_bytes = to_bytes(rs->md.chunk_sectors);
3728 
3729 	blk_limits_io_min(limits, chunk_size_bytes);
3730 	blk_limits_io_opt(limits, chunk_size_bytes * mddev_data_stripes(rs));
3731 }
3732 
3733 static void raid_postsuspend(struct dm_target *ti)
3734 {
3735 	struct raid_set *rs = ti->private;
3736 
3737 	if (!test_and_set_bit(RT_FLAG_RS_SUSPENDED, &rs->runtime_flags)) {
3738 		/* Writes have to be stopped before suspending to avoid deadlocks. */
3739 		if (!test_bit(MD_RECOVERY_FROZEN, &rs->md.recovery))
3740 			md_stop_writes(&rs->md);
3741 
3742 		mddev_lock_nointr(&rs->md);
3743 		mddev_suspend(&rs->md);
3744 		mddev_unlock(&rs->md);
3745 	}
3746 }
3747 
3748 static void attempt_restore_of_faulty_devices(struct raid_set *rs)
3749 {
3750 	int i;
3751 	uint64_t cleared_failed_devices[DISKS_ARRAY_ELEMS];
3752 	unsigned long flags;
3753 	bool cleared = false;
3754 	struct dm_raid_superblock *sb;
3755 	struct mddev *mddev = &rs->md;
3756 	struct md_rdev *r;
3757 
3758 	/* RAID personalities have to provide hot add/remove methods or we need to bail out. */
3759 	if (!mddev->pers || !mddev->pers->hot_add_disk || !mddev->pers->hot_remove_disk)
3760 		return;
3761 
3762 	memset(cleared_failed_devices, 0, sizeof(cleared_failed_devices));
3763 
3764 	for (i = 0; i < mddev->raid_disks; i++) {
3765 		r = &rs->dev[i].rdev;
3766 		/* HM FIXME: enhance journal device recovery processing */
3767 		if (test_bit(Journal, &r->flags))
3768 			continue;
3769 
3770 		if (test_bit(Faulty, &r->flags) &&
3771 		    r->meta_bdev && !read_disk_sb(r, r->sb_size, true)) {
3772 			DMINFO("Faulty %s device #%d has readable super block."
3773 			       "  Attempting to revive it.",
3774 			       rs->raid_type->name, i);
3775 
3776 			/*
3777 			 * Faulty bit may be set, but sometimes the array can
3778 			 * be suspended before the personalities can respond
3779 			 * by removing the device from the array (i.e. calling
3780 			 * 'hot_remove_disk').	If they haven't yet removed
3781 			 * the failed device, its 'raid_disk' number will be
3782 			 * '>= 0' - meaning we must call this function
3783 			 * ourselves.
3784 			 */
3785 			flags = r->flags;
3786 			clear_bit(In_sync, &r->flags); /* Mandatory for hot remove. */
3787 			if (r->raid_disk >= 0) {
3788 				if (mddev->pers->hot_remove_disk(mddev, r)) {
3789 					/* Failed to revive this device, try next */
3790 					r->flags = flags;
3791 					continue;
3792 				}
3793 			} else
3794 				r->raid_disk = r->saved_raid_disk = i;
3795 
3796 			clear_bit(Faulty, &r->flags);
3797 			clear_bit(WriteErrorSeen, &r->flags);
3798 
3799 			if (mddev->pers->hot_add_disk(mddev, r)) {
3800 				/* Failed to revive this device, try next */
3801 				r->raid_disk = r->saved_raid_disk = -1;
3802 				r->flags = flags;
3803 			} else {
3804 				clear_bit(In_sync, &r->flags);
3805 				r->recovery_offset = 0;
3806 				set_bit(i, (void *) cleared_failed_devices);
3807 				cleared = true;
3808 			}
3809 		}
3810 	}
3811 
3812 	/* If any failed devices could be cleared, update all sbs failed_devices bits */
3813 	if (cleared) {
3814 		uint64_t failed_devices[DISKS_ARRAY_ELEMS];
3815 
3816 		rdev_for_each(r, &rs->md) {
3817 			if (test_bit(Journal, &r->flags))
3818 				continue;
3819 
3820 			sb = page_address(r->sb_page);
3821 			sb_retrieve_failed_devices(sb, failed_devices);
3822 
3823 			for (i = 0; i < DISKS_ARRAY_ELEMS; i++)
3824 				failed_devices[i] &= ~cleared_failed_devices[i];
3825 
3826 			sb_update_failed_devices(sb, failed_devices);
3827 		}
3828 	}
3829 }
3830 
3831 static int __load_dirty_region_bitmap(struct raid_set *rs)
3832 {
3833 	int r = 0;
3834 
3835 	/* Try loading the bitmap unless "raid0", which does not have one */
3836 	if (!rs_is_raid0(rs) &&
3837 	    !test_and_set_bit(RT_FLAG_RS_BITMAP_LOADED, &rs->runtime_flags)) {
3838 		r = md_bitmap_load(&rs->md);
3839 		if (r)
3840 			DMERR("Failed to load bitmap");
3841 	}
3842 
3843 	return r;
3844 }
3845 
3846 /* Enforce updating all superblocks */
3847 static void rs_update_sbs(struct raid_set *rs)
3848 {
3849 	struct mddev *mddev = &rs->md;
3850 	int ro = mddev->ro;
3851 
3852 	set_bit(MD_SB_CHANGE_DEVS, &mddev->sb_flags);
3853 	mddev->ro = 0;
3854 	md_update_sb(mddev, 1);
3855 	mddev->ro = ro;
3856 }
3857 
3858 /*
3859  * Reshape changes raid algorithm of @rs to new one within personality
3860  * (e.g. raid6_zr -> raid6_nc), changes stripe size, adds/removes
3861  * disks from a raid set thus growing/shrinking it or resizes the set
3862  *
3863  * Call mddev_lock_nointr() before!
3864  */
3865 static int rs_start_reshape(struct raid_set *rs)
3866 {
3867 	int r;
3868 	struct mddev *mddev = &rs->md;
3869 	struct md_personality *pers = mddev->pers;
3870 
3871 	/* Don't allow the sync thread to work until the table gets reloaded. */
3872 	set_bit(MD_RECOVERY_WAIT, &mddev->recovery);
3873 
3874 	r = rs_setup_reshape(rs);
3875 	if (r)
3876 		return r;
3877 
3878 	/*
3879 	 * Check any reshape constraints enforced by the personalility
3880 	 *
3881 	 * May as well already kick the reshape off so that * pers->start_reshape() becomes optional.
3882 	 */
3883 	r = pers->check_reshape(mddev);
3884 	if (r) {
3885 		rs->ti->error = "pers->check_reshape() failed";
3886 		return r;
3887 	}
3888 
3889 	/*
3890 	 * Personality may not provide start reshape method in which
3891 	 * case check_reshape above has already covered everything
3892 	 */
3893 	if (pers->start_reshape) {
3894 		r = pers->start_reshape(mddev);
3895 		if (r) {
3896 			rs->ti->error = "pers->start_reshape() failed";
3897 			return r;
3898 		}
3899 	}
3900 
3901 	/*
3902 	 * Now reshape got set up, update superblocks to
3903 	 * reflect the fact so that a table reload will
3904 	 * access proper superblock content in the ctr.
3905 	 */
3906 	rs_update_sbs(rs);
3907 
3908 	return 0;
3909 }
3910 
3911 static int raid_preresume(struct dm_target *ti)
3912 {
3913 	int r;
3914 	struct raid_set *rs = ti->private;
3915 	struct mddev *mddev = &rs->md;
3916 
3917 	/* This is a resume after a suspend of the set -> it's already started. */
3918 	if (test_and_set_bit(RT_FLAG_RS_PRERESUMED, &rs->runtime_flags))
3919 		return 0;
3920 
3921 	/*
3922 	 * The superblocks need to be updated on disk if the
3923 	 * array is new or new devices got added (thus zeroed
3924 	 * out by userspace) or __load_dirty_region_bitmap
3925 	 * will overwrite them in core with old data or fail.
3926 	 */
3927 	if (test_bit(RT_FLAG_UPDATE_SBS, &rs->runtime_flags))
3928 		rs_update_sbs(rs);
3929 
3930 	/* Load the bitmap from disk unless raid0 */
3931 	r = __load_dirty_region_bitmap(rs);
3932 	if (r)
3933 		return r;
3934 
3935 	/* We are extending the raid set size, adjust mddev/md_rdev sizes and set capacity. */
3936 	if (test_bit(RT_FLAG_RS_GROW, &rs->runtime_flags)) {
3937 		mddev->array_sectors = rs->array_sectors;
3938 		mddev->dev_sectors = rs->dev_sectors;
3939 		rs_set_rdev_sectors(rs);
3940 		rs_set_capacity(rs);
3941 	}
3942 
3943 	/* Resize bitmap to adjust to changed region size (aka MD bitmap chunksize) or grown device size */
3944         if (test_bit(RT_FLAG_RS_BITMAP_LOADED, &rs->runtime_flags) && mddev->bitmap &&
3945 	    (test_bit(RT_FLAG_RS_GROW, &rs->runtime_flags) ||
3946 	     (rs->requested_bitmap_chunk_sectors &&
3947 	       mddev->bitmap_info.chunksize != to_bytes(rs->requested_bitmap_chunk_sectors)))) {
3948 		int chunksize = to_bytes(rs->requested_bitmap_chunk_sectors) ?: mddev->bitmap_info.chunksize;
3949 
3950 		r = md_bitmap_resize(mddev->bitmap, mddev->dev_sectors, chunksize, 0);
3951 		if (r)
3952 			DMERR("Failed to resize bitmap");
3953 	}
3954 
3955 	/* Check for any resize/reshape on @rs and adjust/initiate */
3956 	/* Be prepared for mddev_resume() in raid_resume() */
3957 	set_bit(MD_RECOVERY_FROZEN, &mddev->recovery);
3958 	if (mddev->recovery_cp && mddev->recovery_cp < MaxSector) {
3959 		set_bit(MD_RECOVERY_REQUESTED, &mddev->recovery);
3960 		mddev->resync_min = mddev->recovery_cp;
3961 		if (test_bit(RT_FLAG_RS_GROW, &rs->runtime_flags))
3962 			mddev->resync_max_sectors = mddev->dev_sectors;
3963 	}
3964 
3965 	/* Check for any reshape request unless new raid set */
3966 	if (test_bit(RT_FLAG_RESHAPE_RS, &rs->runtime_flags)) {
3967 		/* Initiate a reshape. */
3968 		rs_set_rdev_sectors(rs);
3969 		mddev_lock_nointr(mddev);
3970 		r = rs_start_reshape(rs);
3971 		mddev_unlock(mddev);
3972 		if (r)
3973 			DMWARN("Failed to check/start reshape, continuing without change");
3974 		r = 0;
3975 	}
3976 
3977 	return r;
3978 }
3979 
3980 static void raid_resume(struct dm_target *ti)
3981 {
3982 	struct raid_set *rs = ti->private;
3983 	struct mddev *mddev = &rs->md;
3984 
3985 	if (test_and_set_bit(RT_FLAG_RS_RESUMED, &rs->runtime_flags)) {
3986 		/*
3987 		 * A secondary resume while the device is active.
3988 		 * Take this opportunity to check whether any failed
3989 		 * devices are reachable again.
3990 		 */
3991 		attempt_restore_of_faulty_devices(rs);
3992 	}
3993 
3994 	if (test_and_clear_bit(RT_FLAG_RS_SUSPENDED, &rs->runtime_flags)) {
3995 		/* Only reduce raid set size before running a disk removing reshape. */
3996 		if (mddev->delta_disks < 0)
3997 			rs_set_capacity(rs);
3998 
3999 		mddev_lock_nointr(mddev);
4000 		clear_bit(MD_RECOVERY_FROZEN, &mddev->recovery);
4001 		mddev->ro = 0;
4002 		mddev->in_sync = 0;
4003 		mddev_resume(mddev);
4004 		mddev_unlock(mddev);
4005 	}
4006 }
4007 
4008 static struct target_type raid_target = {
4009 	.name = "raid",
4010 	.version = {1, 15, 1},
4011 	.module = THIS_MODULE,
4012 	.ctr = raid_ctr,
4013 	.dtr = raid_dtr,
4014 	.map = raid_map,
4015 	.status = raid_status,
4016 	.message = raid_message,
4017 	.iterate_devices = raid_iterate_devices,
4018 	.io_hints = raid_io_hints,
4019 	.postsuspend = raid_postsuspend,
4020 	.preresume = raid_preresume,
4021 	.resume = raid_resume,
4022 };
4023 
4024 static int __init dm_raid_init(void)
4025 {
4026 	DMINFO("Loading target version %u.%u.%u",
4027 	       raid_target.version[0],
4028 	       raid_target.version[1],
4029 	       raid_target.version[2]);
4030 	return dm_register_target(&raid_target);
4031 }
4032 
4033 static void __exit dm_raid_exit(void)
4034 {
4035 	dm_unregister_target(&raid_target);
4036 }
4037 
4038 module_init(dm_raid_init);
4039 module_exit(dm_raid_exit);
4040 
4041 module_param(devices_handle_discard_safely, bool, 0644);
4042 MODULE_PARM_DESC(devices_handle_discard_safely,
4043 		 "Set to Y if all devices in each array reliably return zeroes on reads from discarded regions");
4044 
4045 MODULE_DESCRIPTION(DM_NAME " raid0/1/10/4/5/6 target");
4046 MODULE_ALIAS("dm-raid0");
4047 MODULE_ALIAS("dm-raid1");
4048 MODULE_ALIAS("dm-raid10");
4049 MODULE_ALIAS("dm-raid4");
4050 MODULE_ALIAS("dm-raid5");
4051 MODULE_ALIAS("dm-raid6");
4052 MODULE_AUTHOR("Neil Brown <dm-devel@redhat.com>");
4053 MODULE_AUTHOR("Heinz Mauelshagen <dm-devel@redhat.com>");
4054 MODULE_LICENSE("GPL");
4055