xref: /linux/drivers/md/dm-raid.c (revision e9f0878c4b2004ac19581274c1ae4c61ae3ca70e)
1 /*
2  * Copyright (C) 2010-2011 Neil Brown
3  * Copyright (C) 2010-2017 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 /* Global list of all raid sets */
33 static LIST_HEAD(raid_sets);
34 
35 static bool devices_handle_discard_safely = false;
36 
37 /*
38  * The following flags are used by dm-raid.c to set up the array state.
39  * They must be cleared before md_run is called.
40  */
41 #define FirstUse 10		/* rdev flag */
42 
43 struct raid_dev {
44 	/*
45 	 * Two DM devices, one to hold metadata and one to hold the
46 	 * actual data/parity.	The reason for this is to not confuse
47 	 * ti->len and give more flexibility in altering size and
48 	 * characteristics.
49 	 *
50 	 * While it is possible for this device to be associated
51 	 * with a different physical device than the data_dev, it
52 	 * is intended for it to be the same.
53 	 *    |--------- Physical Device ---------|
54 	 *    |- meta_dev -|------ data_dev ------|
55 	 */
56 	struct dm_dev *meta_dev;
57 	struct dm_dev *data_dev;
58 	struct md_rdev rdev;
59 };
60 
61 /*
62  * Bits for establishing rs->ctr_flags
63  *
64  * 1 = no flag value
65  * 2 = flag with value
66  */
67 #define __CTR_FLAG_SYNC			0  /* 1 */ /* Not with raid0! */
68 #define __CTR_FLAG_NOSYNC		1  /* 1 */ /* Not with raid0! */
69 #define __CTR_FLAG_REBUILD		2  /* 2 */ /* Not with raid0! */
70 #define __CTR_FLAG_DAEMON_SLEEP		3  /* 2 */ /* Not with raid0! */
71 #define __CTR_FLAG_MIN_RECOVERY_RATE	4  /* 2 */ /* Not with raid0! */
72 #define __CTR_FLAG_MAX_RECOVERY_RATE	5  /* 2 */ /* Not with raid0! */
73 #define __CTR_FLAG_MAX_WRITE_BEHIND	6  /* 2 */ /* Only with raid1! */
74 #define __CTR_FLAG_WRITE_MOSTLY		7  /* 2 */ /* Only with raid1! */
75 #define __CTR_FLAG_STRIPE_CACHE		8  /* 2 */ /* Only with raid4/5/6! */
76 #define __CTR_FLAG_REGION_SIZE		9  /* 2 */ /* Not with raid0! */
77 #define __CTR_FLAG_RAID10_COPIES	10 /* 2 */ /* Only with raid10 */
78 #define __CTR_FLAG_RAID10_FORMAT	11 /* 2 */ /* Only with raid10 */
79 /* New for v1.9.0 */
80 #define __CTR_FLAG_DELTA_DISKS		12 /* 2 */ /* Only with reshapable raid1/4/5/6/10! */
81 #define __CTR_FLAG_DATA_OFFSET		13 /* 2 */ /* Only with reshapable raid4/5/6/10! */
82 #define __CTR_FLAG_RAID10_USE_NEAR_SETS 14 /* 2 */ /* Only with raid10! */
83 
84 /* New for v1.10.0 */
85 #define __CTR_FLAG_JOURNAL_DEV		15 /* 2 */ /* Only with raid4/5/6 (journal device)! */
86 
87 /* New for v1.11.1 */
88 #define __CTR_FLAG_JOURNAL_MODE		16 /* 2 */ /* Only with raid4/5/6 (journal mode)! */
89 
90 /*
91  * Flags for rs->ctr_flags field.
92  */
93 #define CTR_FLAG_SYNC			(1 << __CTR_FLAG_SYNC)
94 #define CTR_FLAG_NOSYNC			(1 << __CTR_FLAG_NOSYNC)
95 #define CTR_FLAG_REBUILD		(1 << __CTR_FLAG_REBUILD)
96 #define CTR_FLAG_DAEMON_SLEEP		(1 << __CTR_FLAG_DAEMON_SLEEP)
97 #define CTR_FLAG_MIN_RECOVERY_RATE	(1 << __CTR_FLAG_MIN_RECOVERY_RATE)
98 #define CTR_FLAG_MAX_RECOVERY_RATE	(1 << __CTR_FLAG_MAX_RECOVERY_RATE)
99 #define CTR_FLAG_MAX_WRITE_BEHIND	(1 << __CTR_FLAG_MAX_WRITE_BEHIND)
100 #define CTR_FLAG_WRITE_MOSTLY		(1 << __CTR_FLAG_WRITE_MOSTLY)
101 #define CTR_FLAG_STRIPE_CACHE		(1 << __CTR_FLAG_STRIPE_CACHE)
102 #define CTR_FLAG_REGION_SIZE		(1 << __CTR_FLAG_REGION_SIZE)
103 #define CTR_FLAG_RAID10_COPIES		(1 << __CTR_FLAG_RAID10_COPIES)
104 #define CTR_FLAG_RAID10_FORMAT		(1 << __CTR_FLAG_RAID10_FORMAT)
105 #define CTR_FLAG_DELTA_DISKS		(1 << __CTR_FLAG_DELTA_DISKS)
106 #define CTR_FLAG_DATA_OFFSET		(1 << __CTR_FLAG_DATA_OFFSET)
107 #define CTR_FLAG_RAID10_USE_NEAR_SETS	(1 << __CTR_FLAG_RAID10_USE_NEAR_SETS)
108 #define CTR_FLAG_JOURNAL_DEV		(1 << __CTR_FLAG_JOURNAL_DEV)
109 #define CTR_FLAG_JOURNAL_MODE		(1 << __CTR_FLAG_JOURNAL_MODE)
110 
111 /*
112  * Definitions of various constructor flags to
113  * be used in checks of valid / invalid flags
114  * per raid level.
115  */
116 /* Define all any sync flags */
117 #define	CTR_FLAGS_ANY_SYNC		(CTR_FLAG_SYNC | CTR_FLAG_NOSYNC)
118 
119 /* Define flags for options without argument (e.g. 'nosync') */
120 #define	CTR_FLAG_OPTIONS_NO_ARGS	(CTR_FLAGS_ANY_SYNC | \
121 					 CTR_FLAG_RAID10_USE_NEAR_SETS)
122 
123 /* Define flags for options with one argument (e.g. 'delta_disks +2') */
124 #define CTR_FLAG_OPTIONS_ONE_ARG (CTR_FLAG_REBUILD | \
125 				  CTR_FLAG_WRITE_MOSTLY | \
126 				  CTR_FLAG_DAEMON_SLEEP | \
127 				  CTR_FLAG_MIN_RECOVERY_RATE | \
128 				  CTR_FLAG_MAX_RECOVERY_RATE | \
129 				  CTR_FLAG_MAX_WRITE_BEHIND | \
130 				  CTR_FLAG_STRIPE_CACHE | \
131 				  CTR_FLAG_REGION_SIZE | \
132 				  CTR_FLAG_RAID10_COPIES | \
133 				  CTR_FLAG_RAID10_FORMAT | \
134 				  CTR_FLAG_DELTA_DISKS | \
135 				  CTR_FLAG_DATA_OFFSET)
136 
137 /* Valid options definitions per raid level... */
138 
139 /* "raid0" does only accept data offset */
140 #define RAID0_VALID_FLAGS	(CTR_FLAG_DATA_OFFSET)
141 
142 /* "raid1" does not accept stripe cache, data offset, delta_disks or any raid10 options */
143 #define RAID1_VALID_FLAGS	(CTR_FLAGS_ANY_SYNC | \
144 				 CTR_FLAG_REBUILD | \
145 				 CTR_FLAG_WRITE_MOSTLY | \
146 				 CTR_FLAG_DAEMON_SLEEP | \
147 				 CTR_FLAG_MIN_RECOVERY_RATE | \
148 				 CTR_FLAG_MAX_RECOVERY_RATE | \
149 				 CTR_FLAG_MAX_WRITE_BEHIND | \
150 				 CTR_FLAG_REGION_SIZE | \
151 				 CTR_FLAG_DELTA_DISKS | \
152 				 CTR_FLAG_DATA_OFFSET)
153 
154 /* "raid10" does not accept any raid1 or stripe cache options */
155 #define RAID10_VALID_FLAGS	(CTR_FLAGS_ANY_SYNC | \
156 				 CTR_FLAG_REBUILD | \
157 				 CTR_FLAG_DAEMON_SLEEP | \
158 				 CTR_FLAG_MIN_RECOVERY_RATE | \
159 				 CTR_FLAG_MAX_RECOVERY_RATE | \
160 				 CTR_FLAG_REGION_SIZE | \
161 				 CTR_FLAG_RAID10_COPIES | \
162 				 CTR_FLAG_RAID10_FORMAT | \
163 				 CTR_FLAG_DELTA_DISKS | \
164 				 CTR_FLAG_DATA_OFFSET | \
165 				 CTR_FLAG_RAID10_USE_NEAR_SETS)
166 
167 /*
168  * "raid4/5/6" do not accept any raid1 or raid10 specific options
169  *
170  * "raid6" does not accept "nosync", because it is not guaranteed
171  * that both parity and q-syndrome are being written properly with
172  * any writes
173  */
174 #define RAID45_VALID_FLAGS	(CTR_FLAGS_ANY_SYNC | \
175 				 CTR_FLAG_REBUILD | \
176 				 CTR_FLAG_DAEMON_SLEEP | \
177 				 CTR_FLAG_MIN_RECOVERY_RATE | \
178 				 CTR_FLAG_MAX_RECOVERY_RATE | \
179 				 CTR_FLAG_STRIPE_CACHE | \
180 				 CTR_FLAG_REGION_SIZE | \
181 				 CTR_FLAG_DELTA_DISKS | \
182 				 CTR_FLAG_DATA_OFFSET | \
183 				 CTR_FLAG_JOURNAL_DEV | \
184 				 CTR_FLAG_JOURNAL_MODE)
185 
186 #define RAID6_VALID_FLAGS	(CTR_FLAG_SYNC | \
187 				 CTR_FLAG_REBUILD | \
188 				 CTR_FLAG_DAEMON_SLEEP | \
189 				 CTR_FLAG_MIN_RECOVERY_RATE | \
190 				 CTR_FLAG_MAX_RECOVERY_RATE | \
191 				 CTR_FLAG_STRIPE_CACHE | \
192 				 CTR_FLAG_REGION_SIZE | \
193 				 CTR_FLAG_DELTA_DISKS | \
194 				 CTR_FLAG_DATA_OFFSET | \
195 				 CTR_FLAG_JOURNAL_DEV | \
196 				 CTR_FLAG_JOURNAL_MODE)
197 /* ...valid options definitions per raid level */
198 
199 /*
200  * Flags for rs->runtime_flags field
201  * (RT_FLAG prefix meaning "runtime flag")
202  *
203  * These are all internal and used to define runtime state,
204  * e.g. to prevent another resume from preresume processing
205  * the raid set all over again.
206  */
207 #define RT_FLAG_RS_PRERESUMED		0
208 #define RT_FLAG_RS_RESUMED		1
209 #define RT_FLAG_RS_BITMAP_LOADED	2
210 #define RT_FLAG_UPDATE_SBS		3
211 #define RT_FLAG_RESHAPE_RS		4
212 #define RT_FLAG_RS_SUSPENDED		5
213 #define RT_FLAG_RS_IN_SYNC		6
214 #define RT_FLAG_RS_RESYNCING		7
215 
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 	struct list_head list;
231 
232 	uint32_t stripe_cache_entries;
233 	unsigned long ctr_flags;
234 	unsigned long runtime_flags;
235 
236 	uint64_t rebuild_disks[DISKS_ARRAY_ELEMS];
237 
238 	int raid_disks;
239 	int delta_disks;
240 	int data_offset;
241 	int raid10_copies;
242 	int requested_bitmap_chunk_sectors;
243 
244 	struct mddev md;
245 	struct raid_type *raid_type;
246 	struct dm_target_callbacks callbacks;
247 
248 	/* Optional raid4/5/6 journal device */
249 	struct journal_dev {
250 		struct dm_dev *dev;
251 		struct md_rdev rdev;
252 		int mode;
253 	} journal_dev;
254 
255 	struct raid_dev dev[0];
256 };
257 
258 static void rs_config_backup(struct raid_set *rs, struct rs_layout *l)
259 {
260 	struct mddev *mddev = &rs->md;
261 
262 	l->new_level = mddev->new_level;
263 	l->new_layout = mddev->new_layout;
264 	l->new_chunk_sectors = mddev->new_chunk_sectors;
265 }
266 
267 static void rs_config_restore(struct raid_set *rs, struct rs_layout *l)
268 {
269 	struct mddev *mddev = &rs->md;
270 
271 	mddev->new_level = l->new_level;
272 	mddev->new_layout = l->new_layout;
273 	mddev->new_chunk_sectors = l->new_chunk_sectors;
274 }
275 
276 /* Find any raid_set in active slot for @rs on global list */
277 static struct raid_set *rs_find_active(struct raid_set *rs)
278 {
279 	struct raid_set *r;
280 	struct mapped_device *md = dm_table_get_md(rs->ti->table);
281 
282 	list_for_each_entry(r, &raid_sets, list)
283 		if (r != rs && dm_table_get_md(r->ti->table) == md)
284 			return r;
285 
286 	return NULL;
287 }
288 
289 /* raid10 algorithms (i.e. formats) */
290 #define	ALGORITHM_RAID10_DEFAULT	0
291 #define	ALGORITHM_RAID10_NEAR		1
292 #define	ALGORITHM_RAID10_OFFSET		2
293 #define	ALGORITHM_RAID10_FAR		3
294 
295 /* Supported raid types and properties. */
296 static struct raid_type {
297 	const char *name;		/* RAID algorithm. */
298 	const char *descr;		/* Descriptor text for logging. */
299 	const unsigned int parity_devs;	/* # of parity devices. */
300 	const unsigned int minimal_devs;/* minimal # of devices in set. */
301 	const unsigned int level;	/* RAID level. */
302 	const unsigned int algorithm;	/* RAID algorithm. */
303 } raid_types[] = {
304 	{"raid0",	  "raid0 (striping)",			    0, 2, 0,  0 /* NONE */},
305 	{"raid1",	  "raid1 (mirroring)",			    0, 2, 1,  0 /* NONE */},
306 	{"raid10_far",	  "raid10 far (striped mirrors)",	    0, 2, 10, ALGORITHM_RAID10_FAR},
307 	{"raid10_offset", "raid10 offset (striped mirrors)",	    0, 2, 10, ALGORITHM_RAID10_OFFSET},
308 	{"raid10_near",	  "raid10 near (striped mirrors)",	    0, 2, 10, ALGORITHM_RAID10_NEAR},
309 	{"raid10",	  "raid10 (striped mirrors)",		    0, 2, 10, ALGORITHM_RAID10_DEFAULT},
310 	{"raid4",	  "raid4 (dedicated first parity disk)",    1, 2, 5,  ALGORITHM_PARITY_0}, /* raid4 layout = raid5_0 */
311 	{"raid5_n",	  "raid5 (dedicated last parity disk)",	    1, 2, 5,  ALGORITHM_PARITY_N},
312 	{"raid5_ls",	  "raid5 (left symmetric)",		    1, 2, 5,  ALGORITHM_LEFT_SYMMETRIC},
313 	{"raid5_rs",	  "raid5 (right symmetric)",		    1, 2, 5,  ALGORITHM_RIGHT_SYMMETRIC},
314 	{"raid5_la",	  "raid5 (left asymmetric)",		    1, 2, 5,  ALGORITHM_LEFT_ASYMMETRIC},
315 	{"raid5_ra",	  "raid5 (right asymmetric)",		    1, 2, 5,  ALGORITHM_RIGHT_ASYMMETRIC},
316 	{"raid6_zr",	  "raid6 (zero restart)",		    2, 4, 6,  ALGORITHM_ROTATING_ZERO_RESTART},
317 	{"raid6_nr",	  "raid6 (N restart)",			    2, 4, 6,  ALGORITHM_ROTATING_N_RESTART},
318 	{"raid6_nc",	  "raid6 (N continue)",			    2, 4, 6,  ALGORITHM_ROTATING_N_CONTINUE},
319 	{"raid6_n_6",	  "raid6 (dedicated parity/Q n/6)",	    2, 4, 6,  ALGORITHM_PARITY_N_6},
320 	{"raid6_ls_6",	  "raid6 (left symmetric dedicated Q 6)",   2, 4, 6,  ALGORITHM_LEFT_SYMMETRIC_6},
321 	{"raid6_rs_6",	  "raid6 (right symmetric dedicated Q 6)",  2, 4, 6,  ALGORITHM_RIGHT_SYMMETRIC_6},
322 	{"raid6_la_6",	  "raid6 (left asymmetric dedicated Q 6)",  2, 4, 6,  ALGORITHM_LEFT_ASYMMETRIC_6},
323 	{"raid6_ra_6",	  "raid6 (right asymmetric dedicated Q 6)", 2, 4, 6,  ALGORITHM_RIGHT_ASYMMETRIC_6}
324 };
325 
326 /* True, if @v is in inclusive range [@min, @max] */
327 static bool __within_range(long v, long min, long max)
328 {
329 	return v >= min && v <= max;
330 }
331 
332 /* All table line arguments are defined here */
333 static struct arg_name_flag {
334 	const unsigned long flag;
335 	const char *name;
336 } __arg_name_flags[] = {
337 	{ CTR_FLAG_SYNC, "sync"},
338 	{ CTR_FLAG_NOSYNC, "nosync"},
339 	{ CTR_FLAG_REBUILD, "rebuild"},
340 	{ CTR_FLAG_DAEMON_SLEEP, "daemon_sleep"},
341 	{ CTR_FLAG_MIN_RECOVERY_RATE, "min_recovery_rate"},
342 	{ CTR_FLAG_MAX_RECOVERY_RATE, "max_recovery_rate"},
343 	{ CTR_FLAG_MAX_WRITE_BEHIND, "max_write_behind"},
344 	{ CTR_FLAG_WRITE_MOSTLY, "write_mostly"},
345 	{ CTR_FLAG_STRIPE_CACHE, "stripe_cache"},
346 	{ CTR_FLAG_REGION_SIZE, "region_size"},
347 	{ CTR_FLAG_RAID10_COPIES, "raid10_copies"},
348 	{ CTR_FLAG_RAID10_FORMAT, "raid10_format"},
349 	{ CTR_FLAG_DATA_OFFSET, "data_offset"},
350 	{ CTR_FLAG_DELTA_DISKS, "delta_disks"},
351 	{ CTR_FLAG_RAID10_USE_NEAR_SETS, "raid10_use_near_sets"},
352 	{ CTR_FLAG_JOURNAL_DEV, "journal_dev" },
353 	{ CTR_FLAG_JOURNAL_MODE, "journal_mode" },
354 };
355 
356 /* Return argument name string for given @flag */
357 static const char *dm_raid_arg_name_by_flag(const uint32_t flag)
358 {
359 	if (hweight32(flag) == 1) {
360 		struct arg_name_flag *anf = __arg_name_flags + ARRAY_SIZE(__arg_name_flags);
361 
362 		while (anf-- > __arg_name_flags)
363 			if (flag & anf->flag)
364 				return anf->name;
365 
366 	} else
367 		DMERR("%s called with more than one flag!", __func__);
368 
369 	return NULL;
370 }
371 
372 /* Define correlation of raid456 journal cache modes and dm-raid target line parameters */
373 static struct {
374 	const int mode;
375 	const char *param;
376 } _raid456_journal_mode[] = {
377 	{ R5C_JOURNAL_MODE_WRITE_THROUGH , "writethrough" },
378 	{ R5C_JOURNAL_MODE_WRITE_BACK    , "writeback" }
379 };
380 
381 /* Return MD raid4/5/6 journal mode for dm @journal_mode one */
382 static int dm_raid_journal_mode_to_md(const char *mode)
383 {
384 	int m = ARRAY_SIZE(_raid456_journal_mode);
385 
386 	while (m--)
387 		if (!strcasecmp(mode, _raid456_journal_mode[m].param))
388 			return _raid456_journal_mode[m].mode;
389 
390 	return -EINVAL;
391 }
392 
393 /* Return dm-raid raid4/5/6 journal mode string for @mode */
394 static const char *md_journal_mode_to_dm_raid(const int mode)
395 {
396 	int m = ARRAY_SIZE(_raid456_journal_mode);
397 
398 	while (m--)
399 		if (mode == _raid456_journal_mode[m].mode)
400 			return _raid456_journal_mode[m].param;
401 
402 	return "unknown";
403 }
404 
405 /*
406  * Bool helpers to test for various raid levels of a raid set.
407  * It's level as reported by the superblock rather than
408  * the requested raid_type passed to the constructor.
409  */
410 /* Return true, if raid set in @rs is raid0 */
411 static bool rs_is_raid0(struct raid_set *rs)
412 {
413 	return !rs->md.level;
414 }
415 
416 /* Return true, if raid set in @rs is raid1 */
417 static bool rs_is_raid1(struct raid_set *rs)
418 {
419 	return rs->md.level == 1;
420 }
421 
422 /* Return true, if raid set in @rs is raid10 */
423 static bool rs_is_raid10(struct raid_set *rs)
424 {
425 	return rs->md.level == 10;
426 }
427 
428 /* Return true, if raid set in @rs is level 6 */
429 static bool rs_is_raid6(struct raid_set *rs)
430 {
431 	return rs->md.level == 6;
432 }
433 
434 /* Return true, if raid set in @rs is level 4, 5 or 6 */
435 static bool rs_is_raid456(struct raid_set *rs)
436 {
437 	return __within_range(rs->md.level, 4, 6);
438 }
439 
440 /* Return true, if raid set in @rs is reshapable */
441 static bool __is_raid10_far(int layout);
442 static bool rs_is_reshapable(struct raid_set *rs)
443 {
444 	return rs_is_raid456(rs) ||
445 	       (rs_is_raid10(rs) && !__is_raid10_far(rs->md.new_layout));
446 }
447 
448 /* Return true, if raid set in @rs is recovering */
449 static bool rs_is_recovering(struct raid_set *rs)
450 {
451 	return rs->md.recovery_cp < rs->md.dev_sectors;
452 }
453 
454 /* Return true, if raid set in @rs is reshaping */
455 static bool rs_is_reshaping(struct raid_set *rs)
456 {
457 	return rs->md.reshape_position != MaxSector;
458 }
459 
460 /*
461  * bool helpers to test for various raid levels of a raid type @rt
462  */
463 
464 /* Return true, if raid type in @rt is raid0 */
465 static bool rt_is_raid0(struct raid_type *rt)
466 {
467 	return !rt->level;
468 }
469 
470 /* Return true, if raid type in @rt is raid1 */
471 static bool rt_is_raid1(struct raid_type *rt)
472 {
473 	return rt->level == 1;
474 }
475 
476 /* Return true, if raid type in @rt is raid10 */
477 static bool rt_is_raid10(struct raid_type *rt)
478 {
479 	return rt->level == 10;
480 }
481 
482 /* Return true, if raid type in @rt is raid4/5 */
483 static bool rt_is_raid45(struct raid_type *rt)
484 {
485 	return __within_range(rt->level, 4, 5);
486 }
487 
488 /* Return true, if raid type in @rt is raid6 */
489 static bool rt_is_raid6(struct raid_type *rt)
490 {
491 	return rt->level == 6;
492 }
493 
494 /* Return true, if raid type in @rt is raid4/5/6 */
495 static bool rt_is_raid456(struct raid_type *rt)
496 {
497 	return __within_range(rt->level, 4, 6);
498 }
499 /* END: raid level bools */
500 
501 /* Return valid ctr flags for the raid level of @rs */
502 static unsigned long __valid_flags(struct raid_set *rs)
503 {
504 	if (rt_is_raid0(rs->raid_type))
505 		return RAID0_VALID_FLAGS;
506 	else if (rt_is_raid1(rs->raid_type))
507 		return RAID1_VALID_FLAGS;
508 	else if (rt_is_raid10(rs->raid_type))
509 		return RAID10_VALID_FLAGS;
510 	else if (rt_is_raid45(rs->raid_type))
511 		return RAID45_VALID_FLAGS;
512 	else if (rt_is_raid6(rs->raid_type))
513 		return RAID6_VALID_FLAGS;
514 
515 	return 0;
516 }
517 
518 /*
519  * Check for valid flags set on @rs
520  *
521  * Has to be called after parsing of the ctr flags!
522  */
523 static int rs_check_for_valid_flags(struct raid_set *rs)
524 {
525 	if (rs->ctr_flags & ~__valid_flags(rs)) {
526 		rs->ti->error = "Invalid flags combination";
527 		return -EINVAL;
528 	}
529 
530 	return 0;
531 }
532 
533 /* MD raid10 bit definitions and helpers */
534 #define RAID10_OFFSET			(1 << 16) /* stripes with data copies area adjacent on devices */
535 #define RAID10_BROCKEN_USE_FAR_SETS	(1 << 17) /* Broken in raid10.c: use sets instead of whole stripe rotation */
536 #define RAID10_USE_FAR_SETS		(1 << 18) /* Use sets instead of whole stripe rotation */
537 #define RAID10_FAR_COPIES_SHIFT		8	  /* raid10 # far copies shift (2nd byte of layout) */
538 
539 /* Return md raid10 near copies for @layout */
540 static unsigned int __raid10_near_copies(int layout)
541 {
542 	return layout & 0xFF;
543 }
544 
545 /* Return md raid10 far copies for @layout */
546 static unsigned int __raid10_far_copies(int layout)
547 {
548 	return __raid10_near_copies(layout >> RAID10_FAR_COPIES_SHIFT);
549 }
550 
551 /* Return true if md raid10 offset for @layout */
552 static bool __is_raid10_offset(int layout)
553 {
554 	return !!(layout & RAID10_OFFSET);
555 }
556 
557 /* Return true if md raid10 near for @layout */
558 static bool __is_raid10_near(int layout)
559 {
560 	return !__is_raid10_offset(layout) && __raid10_near_copies(layout) > 1;
561 }
562 
563 /* Return true if md raid10 far for @layout */
564 static bool __is_raid10_far(int layout)
565 {
566 	return !__is_raid10_offset(layout) && __raid10_far_copies(layout) > 1;
567 }
568 
569 /* Return md raid10 layout string for @layout */
570 static const char *raid10_md_layout_to_format(int layout)
571 {
572 	/*
573 	 * Bit 16 stands for "offset"
574 	 * (i.e. adjacent stripes hold copies)
575 	 *
576 	 * Refer to MD's raid10.c for details
577 	 */
578 	if (__is_raid10_offset(layout))
579 		return "offset";
580 
581 	if (__raid10_near_copies(layout) > 1)
582 		return "near";
583 
584 	if (__raid10_far_copies(layout) > 1)
585 		return "far";
586 
587 	return "unknown";
588 }
589 
590 /* Return md raid10 algorithm for @name */
591 static int raid10_name_to_format(const char *name)
592 {
593 	if (!strcasecmp(name, "near"))
594 		return ALGORITHM_RAID10_NEAR;
595 	else if (!strcasecmp(name, "offset"))
596 		return ALGORITHM_RAID10_OFFSET;
597 	else if (!strcasecmp(name, "far"))
598 		return ALGORITHM_RAID10_FAR;
599 
600 	return -EINVAL;
601 }
602 
603 /* Return md raid10 copies for @layout */
604 static unsigned int raid10_md_layout_to_copies(int layout)
605 {
606 	return max(__raid10_near_copies(layout), __raid10_far_copies(layout));
607 }
608 
609 /* Return md raid10 format id for @format string */
610 static int raid10_format_to_md_layout(struct raid_set *rs,
611 				      unsigned int algorithm,
612 				      unsigned int copies)
613 {
614 	unsigned int n = 1, f = 1, r = 0;
615 
616 	/*
617 	 * MD resilienece flaw:
618 	 *
619 	 * enabling use_far_sets for far/offset formats causes copies
620 	 * to be colocated on the same devs together with their origins!
621 	 *
622 	 * -> disable it for now in the definition above
623 	 */
624 	if (algorithm == ALGORITHM_RAID10_DEFAULT ||
625 	    algorithm == ALGORITHM_RAID10_NEAR)
626 		n = copies;
627 
628 	else if (algorithm == ALGORITHM_RAID10_OFFSET) {
629 		f = copies;
630 		r = RAID10_OFFSET;
631 		if (!test_bit(__CTR_FLAG_RAID10_USE_NEAR_SETS, &rs->ctr_flags))
632 			r |= RAID10_USE_FAR_SETS;
633 
634 	} else if (algorithm == ALGORITHM_RAID10_FAR) {
635 		f = copies;
636 		r = !RAID10_OFFSET;
637 		if (!test_bit(__CTR_FLAG_RAID10_USE_NEAR_SETS, &rs->ctr_flags))
638 			r |= RAID10_USE_FAR_SETS;
639 
640 	} else
641 		return -EINVAL;
642 
643 	return r | (f << RAID10_FAR_COPIES_SHIFT) | n;
644 }
645 /* END: MD raid10 bit definitions and helpers */
646 
647 /* Check for any of the raid10 algorithms */
648 static bool __got_raid10(struct raid_type *rtp, const int layout)
649 {
650 	if (rtp->level == 10) {
651 		switch (rtp->algorithm) {
652 		case ALGORITHM_RAID10_DEFAULT:
653 		case ALGORITHM_RAID10_NEAR:
654 			return __is_raid10_near(layout);
655 		case ALGORITHM_RAID10_OFFSET:
656 			return __is_raid10_offset(layout);
657 		case ALGORITHM_RAID10_FAR:
658 			return __is_raid10_far(layout);
659 		default:
660 			break;
661 		}
662 	}
663 
664 	return false;
665 }
666 
667 /* Return raid_type for @name */
668 static struct raid_type *get_raid_type(const char *name)
669 {
670 	struct raid_type *rtp = raid_types + ARRAY_SIZE(raid_types);
671 
672 	while (rtp-- > raid_types)
673 		if (!strcasecmp(rtp->name, name))
674 			return rtp;
675 
676 	return NULL;
677 }
678 
679 /* Return raid_type for @name based derived from @level and @layout */
680 static struct raid_type *get_raid_type_by_ll(const int level, const int layout)
681 {
682 	struct raid_type *rtp = raid_types + ARRAY_SIZE(raid_types);
683 
684 	while (rtp-- > raid_types) {
685 		/* RAID10 special checks based on @layout flags/properties */
686 		if (rtp->level == level &&
687 		    (__got_raid10(rtp, layout) || rtp->algorithm == layout))
688 			return rtp;
689 	}
690 
691 	return NULL;
692 }
693 
694 /* Adjust rdev sectors */
695 static void rs_set_rdev_sectors(struct raid_set *rs)
696 {
697 	struct mddev *mddev = &rs->md;
698 	struct md_rdev *rdev;
699 
700 	/*
701 	 * raid10 sets rdev->sector to the device size, which
702 	 * is unintended in case of out-of-place reshaping
703 	 */
704 	rdev_for_each(rdev, mddev)
705 		if (!test_bit(Journal, &rdev->flags))
706 			rdev->sectors = mddev->dev_sectors;
707 }
708 
709 /*
710  * Change bdev capacity of @rs in case of a disk add/remove reshape
711  */
712 static void rs_set_capacity(struct raid_set *rs)
713 {
714 	struct gendisk *gendisk = dm_disk(dm_table_get_md(rs->ti->table));
715 
716 	set_capacity(gendisk, rs->md.array_sectors);
717 	revalidate_disk(gendisk);
718 }
719 
720 /*
721  * Set the mddev properties in @rs to the current
722  * ones retrieved from the freshest superblock
723  */
724 static void rs_set_cur(struct raid_set *rs)
725 {
726 	struct mddev *mddev = &rs->md;
727 
728 	mddev->new_level = mddev->level;
729 	mddev->new_layout = mddev->layout;
730 	mddev->new_chunk_sectors = mddev->chunk_sectors;
731 }
732 
733 /*
734  * Set the mddev properties in @rs to the new
735  * ones requested by the ctr
736  */
737 static void rs_set_new(struct raid_set *rs)
738 {
739 	struct mddev *mddev = &rs->md;
740 
741 	mddev->level = mddev->new_level;
742 	mddev->layout = mddev->new_layout;
743 	mddev->chunk_sectors = mddev->new_chunk_sectors;
744 	mddev->raid_disks = rs->raid_disks;
745 	mddev->delta_disks = 0;
746 }
747 
748 static struct raid_set *raid_set_alloc(struct dm_target *ti, struct raid_type *raid_type,
749 				       unsigned int raid_devs)
750 {
751 	unsigned int i;
752 	struct raid_set *rs;
753 
754 	if (raid_devs <= raid_type->parity_devs) {
755 		ti->error = "Insufficient number of devices";
756 		return ERR_PTR(-EINVAL);
757 	}
758 
759 	rs = kzalloc(struct_size(rs, dev, raid_devs), GFP_KERNEL);
760 	if (!rs) {
761 		ti->error = "Cannot allocate raid context";
762 		return ERR_PTR(-ENOMEM);
763 	}
764 
765 	mddev_init(&rs->md);
766 
767 	INIT_LIST_HEAD(&rs->list);
768 	rs->raid_disks = raid_devs;
769 	rs->delta_disks = 0;
770 
771 	rs->ti = ti;
772 	rs->raid_type = raid_type;
773 	rs->stripe_cache_entries = 256;
774 	rs->md.raid_disks = raid_devs;
775 	rs->md.level = raid_type->level;
776 	rs->md.new_level = rs->md.level;
777 	rs->md.layout = raid_type->algorithm;
778 	rs->md.new_layout = rs->md.layout;
779 	rs->md.delta_disks = 0;
780 	rs->md.recovery_cp = MaxSector;
781 
782 	for (i = 0; i < raid_devs; i++)
783 		md_rdev_init(&rs->dev[i].rdev);
784 
785 	/* Add @rs to global list. */
786 	list_add(&rs->list, &raid_sets);
787 
788 	/*
789 	 * Remaining items to be initialized by further RAID params:
790 	 *  rs->md.persistent
791 	 *  rs->md.external
792 	 *  rs->md.chunk_sectors
793 	 *  rs->md.new_chunk_sectors
794 	 *  rs->md.dev_sectors
795 	 */
796 
797 	return rs;
798 }
799 
800 /* Free all @rs allocations and remove it from global list. */
801 static void raid_set_free(struct raid_set *rs)
802 {
803 	int i;
804 
805 	if (rs->journal_dev.dev) {
806 		md_rdev_clear(&rs->journal_dev.rdev);
807 		dm_put_device(rs->ti, rs->journal_dev.dev);
808 	}
809 
810 	for (i = 0; i < rs->raid_disks; i++) {
811 		if (rs->dev[i].meta_dev)
812 			dm_put_device(rs->ti, rs->dev[i].meta_dev);
813 		md_rdev_clear(&rs->dev[i].rdev);
814 		if (rs->dev[i].data_dev)
815 			dm_put_device(rs->ti, rs->dev[i].data_dev);
816 	}
817 
818 	list_del(&rs->list);
819 
820 	kfree(rs);
821 }
822 
823 /*
824  * For every device we have two words
825  *  <meta_dev>: meta device name or '-' if missing
826  *  <data_dev>: data device name or '-' if missing
827  *
828  * The following are permitted:
829  *    - -
830  *    - <data_dev>
831  *    <meta_dev> <data_dev>
832  *
833  * The following is not allowed:
834  *    <meta_dev> -
835  *
836  * This code parses those words.  If there is a failure,
837  * the caller must use raid_set_free() to unwind the operations.
838  */
839 static int parse_dev_params(struct raid_set *rs, struct dm_arg_set *as)
840 {
841 	int i;
842 	int rebuild = 0;
843 	int metadata_available = 0;
844 	int r = 0;
845 	const char *arg;
846 
847 	/* Put off the number of raid devices argument to get to dev pairs */
848 	arg = dm_shift_arg(as);
849 	if (!arg)
850 		return -EINVAL;
851 
852 	for (i = 0; i < rs->raid_disks; i++) {
853 		rs->dev[i].rdev.raid_disk = i;
854 
855 		rs->dev[i].meta_dev = NULL;
856 		rs->dev[i].data_dev = NULL;
857 
858 		/*
859 		 * There are no offsets initially.
860 		 * Out of place reshape will set them accordingly.
861 		 */
862 		rs->dev[i].rdev.data_offset = 0;
863 		rs->dev[i].rdev.new_data_offset = 0;
864 		rs->dev[i].rdev.mddev = &rs->md;
865 
866 		arg = dm_shift_arg(as);
867 		if (!arg)
868 			return -EINVAL;
869 
870 		if (strcmp(arg, "-")) {
871 			r = dm_get_device(rs->ti, arg, dm_table_get_mode(rs->ti->table),
872 					  &rs->dev[i].meta_dev);
873 			if (r) {
874 				rs->ti->error = "RAID metadata device lookup failure";
875 				return r;
876 			}
877 
878 			rs->dev[i].rdev.sb_page = alloc_page(GFP_KERNEL);
879 			if (!rs->dev[i].rdev.sb_page) {
880 				rs->ti->error = "Failed to allocate superblock page";
881 				return -ENOMEM;
882 			}
883 		}
884 
885 		arg = dm_shift_arg(as);
886 		if (!arg)
887 			return -EINVAL;
888 
889 		if (!strcmp(arg, "-")) {
890 			if (!test_bit(In_sync, &rs->dev[i].rdev.flags) &&
891 			    (!rs->dev[i].rdev.recovery_offset)) {
892 				rs->ti->error = "Drive designated for rebuild not specified";
893 				return -EINVAL;
894 			}
895 
896 			if (rs->dev[i].meta_dev) {
897 				rs->ti->error = "No data device supplied with metadata device";
898 				return -EINVAL;
899 			}
900 
901 			continue;
902 		}
903 
904 		r = dm_get_device(rs->ti, arg, dm_table_get_mode(rs->ti->table),
905 				  &rs->dev[i].data_dev);
906 		if (r) {
907 			rs->ti->error = "RAID device lookup failure";
908 			return r;
909 		}
910 
911 		if (rs->dev[i].meta_dev) {
912 			metadata_available = 1;
913 			rs->dev[i].rdev.meta_bdev = rs->dev[i].meta_dev->bdev;
914 		}
915 		rs->dev[i].rdev.bdev = rs->dev[i].data_dev->bdev;
916 		list_add_tail(&rs->dev[i].rdev.same_set, &rs->md.disks);
917 		if (!test_bit(In_sync, &rs->dev[i].rdev.flags))
918 			rebuild++;
919 	}
920 
921 	if (rs->journal_dev.dev)
922 		list_add_tail(&rs->journal_dev.rdev.same_set, &rs->md.disks);
923 
924 	if (metadata_available) {
925 		rs->md.external = 0;
926 		rs->md.persistent = 1;
927 		rs->md.major_version = 2;
928 	} else if (rebuild && !rs->md.recovery_cp) {
929 		/*
930 		 * Without metadata, we will not be able to tell if the array
931 		 * is in-sync or not - we must assume it is not.  Therefore,
932 		 * it is impossible to rebuild a drive.
933 		 *
934 		 * Even if there is metadata, the on-disk information may
935 		 * indicate that the array is not in-sync and it will then
936 		 * fail at that time.
937 		 *
938 		 * User could specify 'nosync' option if desperate.
939 		 */
940 		rs->ti->error = "Unable to rebuild drive while array is not in-sync";
941 		return -EINVAL;
942 	}
943 
944 	return 0;
945 }
946 
947 /*
948  * validate_region_size
949  * @rs
950  * @region_size:  region size in sectors.  If 0, pick a size (4MiB default).
951  *
952  * Set rs->md.bitmap_info.chunksize (which really refers to 'region size').
953  * Ensure that (ti->len/region_size < 2^21) - required by MD bitmap.
954  *
955  * Returns: 0 on success, -EINVAL on failure.
956  */
957 static int validate_region_size(struct raid_set *rs, unsigned long region_size)
958 {
959 	unsigned long min_region_size = rs->ti->len / (1 << 21);
960 
961 	if (rs_is_raid0(rs))
962 		return 0;
963 
964 	if (!region_size) {
965 		/*
966 		 * Choose a reasonable default.	 All figures in sectors.
967 		 */
968 		if (min_region_size > (1 << 13)) {
969 			/* If not a power of 2, make it the next power of 2 */
970 			region_size = roundup_pow_of_two(min_region_size);
971 			DMINFO("Choosing default region size of %lu sectors",
972 			       region_size);
973 		} else {
974 			DMINFO("Choosing default region size of 4MiB");
975 			region_size = 1 << 13; /* sectors */
976 		}
977 	} else {
978 		/*
979 		 * Validate user-supplied value.
980 		 */
981 		if (region_size > rs->ti->len) {
982 			rs->ti->error = "Supplied region size is too large";
983 			return -EINVAL;
984 		}
985 
986 		if (region_size < min_region_size) {
987 			DMERR("Supplied region_size (%lu sectors) below minimum (%lu)",
988 			      region_size, min_region_size);
989 			rs->ti->error = "Supplied region size is too small";
990 			return -EINVAL;
991 		}
992 
993 		if (!is_power_of_2(region_size)) {
994 			rs->ti->error = "Region size is not a power of 2";
995 			return -EINVAL;
996 		}
997 
998 		if (region_size < rs->md.chunk_sectors) {
999 			rs->ti->error = "Region size is smaller than the chunk size";
1000 			return -EINVAL;
1001 		}
1002 	}
1003 
1004 	/*
1005 	 * Convert sectors to bytes.
1006 	 */
1007 	rs->md.bitmap_info.chunksize = to_bytes(region_size);
1008 
1009 	return 0;
1010 }
1011 
1012 /*
1013  * validate_raid_redundancy
1014  * @rs
1015  *
1016  * Determine if there are enough devices in the array that haven't
1017  * failed (or are being rebuilt) to form a usable array.
1018  *
1019  * Returns: 0 on success, -EINVAL on failure.
1020  */
1021 static int validate_raid_redundancy(struct raid_set *rs)
1022 {
1023 	unsigned int i, rebuild_cnt = 0;
1024 	unsigned int rebuilds_per_group = 0, copies;
1025 	unsigned int group_size, last_group_start;
1026 
1027 	for (i = 0; i < rs->md.raid_disks; i++)
1028 		if (!test_bit(In_sync, &rs->dev[i].rdev.flags) ||
1029 		    !rs->dev[i].rdev.sb_page)
1030 			rebuild_cnt++;
1031 
1032 	switch (rs->md.level) {
1033 	case 0:
1034 		break;
1035 	case 1:
1036 		if (rebuild_cnt >= rs->md.raid_disks)
1037 			goto too_many;
1038 		break;
1039 	case 4:
1040 	case 5:
1041 	case 6:
1042 		if (rebuild_cnt > rs->raid_type->parity_devs)
1043 			goto too_many;
1044 		break;
1045 	case 10:
1046 		copies = raid10_md_layout_to_copies(rs->md.new_layout);
1047 		if (copies < 2) {
1048 			DMERR("Bogus raid10 data copies < 2!");
1049 			return -EINVAL;
1050 		}
1051 
1052 		if (rebuild_cnt < copies)
1053 			break;
1054 
1055 		/*
1056 		 * It is possible to have a higher rebuild count for RAID10,
1057 		 * as long as the failed devices occur in different mirror
1058 		 * groups (i.e. different stripes).
1059 		 *
1060 		 * When checking "near" format, make sure no adjacent devices
1061 		 * have failed beyond what can be handled.  In addition to the
1062 		 * simple case where the number of devices is a multiple of the
1063 		 * number of copies, we must also handle cases where the number
1064 		 * of devices is not a multiple of the number of copies.
1065 		 * E.g.	   dev1 dev2 dev3 dev4 dev5
1066 		 *	    A	 A    B	   B	C
1067 		 *	    C	 D    D	   E	E
1068 		 */
1069 		if (__is_raid10_near(rs->md.new_layout)) {
1070 			for (i = 0; i < rs->md.raid_disks; i++) {
1071 				if (!(i % copies))
1072 					rebuilds_per_group = 0;
1073 				if ((!rs->dev[i].rdev.sb_page ||
1074 				    !test_bit(In_sync, &rs->dev[i].rdev.flags)) &&
1075 				    (++rebuilds_per_group >= copies))
1076 					goto too_many;
1077 			}
1078 			break;
1079 		}
1080 
1081 		/*
1082 		 * When checking "far" and "offset" formats, we need to ensure
1083 		 * that the device that holds its copy is not also dead or
1084 		 * being rebuilt.  (Note that "far" and "offset" formats only
1085 		 * support two copies right now.  These formats also only ever
1086 		 * use the 'use_far_sets' variant.)
1087 		 *
1088 		 * This check is somewhat complicated by the need to account
1089 		 * for arrays that are not a multiple of (far) copies.	This
1090 		 * results in the need to treat the last (potentially larger)
1091 		 * set differently.
1092 		 */
1093 		group_size = (rs->md.raid_disks / copies);
1094 		last_group_start = (rs->md.raid_disks / group_size) - 1;
1095 		last_group_start *= group_size;
1096 		for (i = 0; i < rs->md.raid_disks; i++) {
1097 			if (!(i % copies) && !(i > last_group_start))
1098 				rebuilds_per_group = 0;
1099 			if ((!rs->dev[i].rdev.sb_page ||
1100 			     !test_bit(In_sync, &rs->dev[i].rdev.flags)) &&
1101 			    (++rebuilds_per_group >= copies))
1102 					goto too_many;
1103 		}
1104 		break;
1105 	default:
1106 		if (rebuild_cnt)
1107 			return -EINVAL;
1108 	}
1109 
1110 	return 0;
1111 
1112 too_many:
1113 	return -EINVAL;
1114 }
1115 
1116 /*
1117  * Possible arguments are...
1118  *	<chunk_size> [optional_args]
1119  *
1120  * Argument definitions
1121  *    <chunk_size>			The number of sectors per disk that
1122  *					will form the "stripe"
1123  *    [[no]sync]			Force or prevent recovery of the
1124  *					entire array
1125  *    [rebuild <idx>]			Rebuild the drive indicated by the index
1126  *    [daemon_sleep <ms>]		Time between bitmap daemon work to
1127  *					clear bits
1128  *    [min_recovery_rate <kB/sec/disk>]	Throttle RAID initialization
1129  *    [max_recovery_rate <kB/sec/disk>]	Throttle RAID initialization
1130  *    [write_mostly <idx>]		Indicate a write mostly drive via index
1131  *    [max_write_behind <sectors>]	See '-write-behind=' (man mdadm)
1132  *    [stripe_cache <sectors>]		Stripe cache size for higher RAIDs
1133  *    [region_size <sectors>]		Defines granularity of bitmap
1134  *    [journal_dev <dev>]		raid4/5/6 journaling deviice
1135  *    					(i.e. write hole closing log)
1136  *
1137  * RAID10-only options:
1138  *    [raid10_copies <# copies>]	Number of copies.  (Default: 2)
1139  *    [raid10_format <near|far|offset>] Layout algorithm.  (Default: near)
1140  */
1141 static int parse_raid_params(struct raid_set *rs, struct dm_arg_set *as,
1142 			     unsigned int num_raid_params)
1143 {
1144 	int value, raid10_format = ALGORITHM_RAID10_DEFAULT;
1145 	unsigned int raid10_copies = 2;
1146 	unsigned int i, write_mostly = 0;
1147 	unsigned int region_size = 0;
1148 	sector_t max_io_len;
1149 	const char *arg, *key;
1150 	struct raid_dev *rd;
1151 	struct raid_type *rt = rs->raid_type;
1152 
1153 	arg = dm_shift_arg(as);
1154 	num_raid_params--; /* Account for chunk_size argument */
1155 
1156 	if (kstrtoint(arg, 10, &value) < 0) {
1157 		rs->ti->error = "Bad numerical argument given for chunk_size";
1158 		return -EINVAL;
1159 	}
1160 
1161 	/*
1162 	 * First, parse the in-order required arguments
1163 	 * "chunk_size" is the only argument of this type.
1164 	 */
1165 	if (rt_is_raid1(rt)) {
1166 		if (value)
1167 			DMERR("Ignoring chunk size parameter for RAID 1");
1168 		value = 0;
1169 	} else if (!is_power_of_2(value)) {
1170 		rs->ti->error = "Chunk size must be a power of 2";
1171 		return -EINVAL;
1172 	} else if (value < 8) {
1173 		rs->ti->error = "Chunk size value is too small";
1174 		return -EINVAL;
1175 	}
1176 
1177 	rs->md.new_chunk_sectors = rs->md.chunk_sectors = value;
1178 
1179 	/*
1180 	 * We set each individual device as In_sync with a completed
1181 	 * 'recovery_offset'.  If there has been a device failure or
1182 	 * replacement then one of the following cases applies:
1183 	 *
1184 	 *   1) User specifies 'rebuild'.
1185 	 *	- Device is reset when param is read.
1186 	 *   2) A new device is supplied.
1187 	 *	- No matching superblock found, resets device.
1188 	 *   3) Device failure was transient and returns on reload.
1189 	 *	- Failure noticed, resets device for bitmap replay.
1190 	 *   4) Device hadn't completed recovery after previous failure.
1191 	 *	- Superblock is read and overrides recovery_offset.
1192 	 *
1193 	 * What is found in the superblocks of the devices is always
1194 	 * authoritative, unless 'rebuild' or '[no]sync' was specified.
1195 	 */
1196 	for (i = 0; i < rs->raid_disks; i++) {
1197 		set_bit(In_sync, &rs->dev[i].rdev.flags);
1198 		rs->dev[i].rdev.recovery_offset = MaxSector;
1199 	}
1200 
1201 	/*
1202 	 * Second, parse the unordered optional arguments
1203 	 */
1204 	for (i = 0; i < num_raid_params; i++) {
1205 		key = dm_shift_arg(as);
1206 		if (!key) {
1207 			rs->ti->error = "Not enough raid parameters given";
1208 			return -EINVAL;
1209 		}
1210 
1211 		if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_NOSYNC))) {
1212 			if (test_and_set_bit(__CTR_FLAG_NOSYNC, &rs->ctr_flags)) {
1213 				rs->ti->error = "Only one 'nosync' argument allowed";
1214 				return -EINVAL;
1215 			}
1216 			continue;
1217 		}
1218 		if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_SYNC))) {
1219 			if (test_and_set_bit(__CTR_FLAG_SYNC, &rs->ctr_flags)) {
1220 				rs->ti->error = "Only one 'sync' argument allowed";
1221 				return -EINVAL;
1222 			}
1223 			continue;
1224 		}
1225 		if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_RAID10_USE_NEAR_SETS))) {
1226 			if (test_and_set_bit(__CTR_FLAG_RAID10_USE_NEAR_SETS, &rs->ctr_flags)) {
1227 				rs->ti->error = "Only one 'raid10_use_new_sets' argument allowed";
1228 				return -EINVAL;
1229 			}
1230 			continue;
1231 		}
1232 
1233 		arg = dm_shift_arg(as);
1234 		i++; /* Account for the argument pairs */
1235 		if (!arg) {
1236 			rs->ti->error = "Wrong number of raid parameters given";
1237 			return -EINVAL;
1238 		}
1239 
1240 		/*
1241 		 * Parameters that take a string value are checked here.
1242 		 */
1243 		/* "raid10_format {near|offset|far} */
1244 		if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_RAID10_FORMAT))) {
1245 			if (test_and_set_bit(__CTR_FLAG_RAID10_FORMAT, &rs->ctr_flags)) {
1246 				rs->ti->error = "Only one 'raid10_format' argument pair allowed";
1247 				return -EINVAL;
1248 			}
1249 			if (!rt_is_raid10(rt)) {
1250 				rs->ti->error = "'raid10_format' is an invalid parameter for this RAID type";
1251 				return -EINVAL;
1252 			}
1253 			raid10_format = raid10_name_to_format(arg);
1254 			if (raid10_format < 0) {
1255 				rs->ti->error = "Invalid 'raid10_format' value given";
1256 				return raid10_format;
1257 			}
1258 			continue;
1259 		}
1260 
1261 		/* "journal_dev <dev>" */
1262 		if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_JOURNAL_DEV))) {
1263 			int r;
1264 			struct md_rdev *jdev;
1265 
1266 			if (test_and_set_bit(__CTR_FLAG_JOURNAL_DEV, &rs->ctr_flags)) {
1267 				rs->ti->error = "Only one raid4/5/6 set journaling device allowed";
1268 				return -EINVAL;
1269 			}
1270 			if (!rt_is_raid456(rt)) {
1271 				rs->ti->error = "'journal_dev' is an invalid parameter for this RAID type";
1272 				return -EINVAL;
1273 			}
1274 			r = dm_get_device(rs->ti, arg, dm_table_get_mode(rs->ti->table),
1275 					  &rs->journal_dev.dev);
1276 			if (r) {
1277 				rs->ti->error = "raid4/5/6 journal device lookup failure";
1278 				return r;
1279 			}
1280 			jdev = &rs->journal_dev.rdev;
1281 			md_rdev_init(jdev);
1282 			jdev->mddev = &rs->md;
1283 			jdev->bdev = rs->journal_dev.dev->bdev;
1284 			jdev->sectors = to_sector(i_size_read(jdev->bdev->bd_inode));
1285 			if (jdev->sectors < MIN_RAID456_JOURNAL_SPACE) {
1286 				rs->ti->error = "No space for raid4/5/6 journal";
1287 				return -ENOSPC;
1288 			}
1289 			rs->journal_dev.mode = R5C_JOURNAL_MODE_WRITE_THROUGH;
1290 			set_bit(Journal, &jdev->flags);
1291 			continue;
1292 		}
1293 
1294 		/* "journal_mode <mode>" ("journal_dev" mandatory!) */
1295 		if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_JOURNAL_MODE))) {
1296 			int r;
1297 
1298 			if (!test_bit(__CTR_FLAG_JOURNAL_DEV, &rs->ctr_flags)) {
1299 				rs->ti->error = "raid4/5/6 'journal_mode' is invalid without 'journal_dev'";
1300 				return -EINVAL;
1301 			}
1302 			if (test_and_set_bit(__CTR_FLAG_JOURNAL_MODE, &rs->ctr_flags)) {
1303 				rs->ti->error = "Only one raid4/5/6 'journal_mode' argument allowed";
1304 				return -EINVAL;
1305 			}
1306 			r = dm_raid_journal_mode_to_md(arg);
1307 			if (r < 0) {
1308 				rs->ti->error = "Invalid 'journal_mode' argument";
1309 				return r;
1310 			}
1311 			rs->journal_dev.mode = r;
1312 			continue;
1313 		}
1314 
1315 		/*
1316 		 * Parameters with number values from here on.
1317 		 */
1318 		if (kstrtoint(arg, 10, &value) < 0) {
1319 			rs->ti->error = "Bad numerical argument given in raid params";
1320 			return -EINVAL;
1321 		}
1322 
1323 		if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_REBUILD))) {
1324 			/*
1325 			 * "rebuild" is being passed in by userspace to provide
1326 			 * indexes of replaced devices and to set up additional
1327 			 * devices on raid level takeover.
1328 			 */
1329 			if (!__within_range(value, 0, rs->raid_disks - 1)) {
1330 				rs->ti->error = "Invalid rebuild index given";
1331 				return -EINVAL;
1332 			}
1333 
1334 			if (test_and_set_bit(value, (void *) rs->rebuild_disks)) {
1335 				rs->ti->error = "rebuild for this index already given";
1336 				return -EINVAL;
1337 			}
1338 
1339 			rd = rs->dev + value;
1340 			clear_bit(In_sync, &rd->rdev.flags);
1341 			clear_bit(Faulty, &rd->rdev.flags);
1342 			rd->rdev.recovery_offset = 0;
1343 			set_bit(__CTR_FLAG_REBUILD, &rs->ctr_flags);
1344 		} else if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_WRITE_MOSTLY))) {
1345 			if (!rt_is_raid1(rt)) {
1346 				rs->ti->error = "write_mostly option is only valid for RAID1";
1347 				return -EINVAL;
1348 			}
1349 
1350 			if (!__within_range(value, 0, rs->md.raid_disks - 1)) {
1351 				rs->ti->error = "Invalid write_mostly index given";
1352 				return -EINVAL;
1353 			}
1354 
1355 			write_mostly++;
1356 			set_bit(WriteMostly, &rs->dev[value].rdev.flags);
1357 			set_bit(__CTR_FLAG_WRITE_MOSTLY, &rs->ctr_flags);
1358 		} else if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_MAX_WRITE_BEHIND))) {
1359 			if (!rt_is_raid1(rt)) {
1360 				rs->ti->error = "max_write_behind option is only valid for RAID1";
1361 				return -EINVAL;
1362 			}
1363 
1364 			if (test_and_set_bit(__CTR_FLAG_MAX_WRITE_BEHIND, &rs->ctr_flags)) {
1365 				rs->ti->error = "Only one max_write_behind argument pair allowed";
1366 				return -EINVAL;
1367 			}
1368 
1369 			/*
1370 			 * In device-mapper, we specify things in sectors, but
1371 			 * MD records this value in kB
1372 			 */
1373 			if (value < 0 || value / 2 > COUNTER_MAX) {
1374 				rs->ti->error = "Max write-behind limit out of range";
1375 				return -EINVAL;
1376 			}
1377 
1378 			rs->md.bitmap_info.max_write_behind = value / 2;
1379 		} else if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_DAEMON_SLEEP))) {
1380 			if (test_and_set_bit(__CTR_FLAG_DAEMON_SLEEP, &rs->ctr_flags)) {
1381 				rs->ti->error = "Only one daemon_sleep argument pair allowed";
1382 				return -EINVAL;
1383 			}
1384 			if (value < 0) {
1385 				rs->ti->error = "daemon sleep period out of range";
1386 				return -EINVAL;
1387 			}
1388 			rs->md.bitmap_info.daemon_sleep = value;
1389 		} else if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_DATA_OFFSET))) {
1390 			/* Userspace passes new data_offset after having extended the the data image LV */
1391 			if (test_and_set_bit(__CTR_FLAG_DATA_OFFSET, &rs->ctr_flags)) {
1392 				rs->ti->error = "Only one data_offset argument pair allowed";
1393 				return -EINVAL;
1394 			}
1395 			/* Ensure sensible data offset */
1396 			if (value < 0 ||
1397 			    (value && (value < MIN_FREE_RESHAPE_SPACE || value % to_sector(PAGE_SIZE)))) {
1398 				rs->ti->error = "Bogus data_offset value";
1399 				return -EINVAL;
1400 			}
1401 			rs->data_offset = value;
1402 		} else if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_DELTA_DISKS))) {
1403 			/* Define the +/-# of disks to add to/remove from the given raid set */
1404 			if (test_and_set_bit(__CTR_FLAG_DELTA_DISKS, &rs->ctr_flags)) {
1405 				rs->ti->error = "Only one delta_disks argument pair allowed";
1406 				return -EINVAL;
1407 			}
1408 			/* Ensure MAX_RAID_DEVICES and raid type minimal_devs! */
1409 			if (!__within_range(abs(value), 1, MAX_RAID_DEVICES - rt->minimal_devs)) {
1410 				rs->ti->error = "Too many delta_disk requested";
1411 				return -EINVAL;
1412 			}
1413 
1414 			rs->delta_disks = value;
1415 		} else if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_STRIPE_CACHE))) {
1416 			if (test_and_set_bit(__CTR_FLAG_STRIPE_CACHE, &rs->ctr_flags)) {
1417 				rs->ti->error = "Only one stripe_cache argument pair allowed";
1418 				return -EINVAL;
1419 			}
1420 
1421 			if (!rt_is_raid456(rt)) {
1422 				rs->ti->error = "Inappropriate argument: stripe_cache";
1423 				return -EINVAL;
1424 			}
1425 
1426 			if (value < 0) {
1427 				rs->ti->error = "Bogus stripe cache entries value";
1428 				return -EINVAL;
1429 			}
1430 			rs->stripe_cache_entries = value;
1431 		} else if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_MIN_RECOVERY_RATE))) {
1432 			if (test_and_set_bit(__CTR_FLAG_MIN_RECOVERY_RATE, &rs->ctr_flags)) {
1433 				rs->ti->error = "Only one min_recovery_rate argument pair allowed";
1434 				return -EINVAL;
1435 			}
1436 
1437 			if (value < 0) {
1438 				rs->ti->error = "min_recovery_rate out of range";
1439 				return -EINVAL;
1440 			}
1441 			rs->md.sync_speed_min = value;
1442 		} else if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_MAX_RECOVERY_RATE))) {
1443 			if (test_and_set_bit(__CTR_FLAG_MAX_RECOVERY_RATE, &rs->ctr_flags)) {
1444 				rs->ti->error = "Only one max_recovery_rate argument pair allowed";
1445 				return -EINVAL;
1446 			}
1447 
1448 			if (value < 0) {
1449 				rs->ti->error = "max_recovery_rate out of range";
1450 				return -EINVAL;
1451 			}
1452 			rs->md.sync_speed_max = value;
1453 		} else if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_REGION_SIZE))) {
1454 			if (test_and_set_bit(__CTR_FLAG_REGION_SIZE, &rs->ctr_flags)) {
1455 				rs->ti->error = "Only one region_size argument pair allowed";
1456 				return -EINVAL;
1457 			}
1458 
1459 			region_size = value;
1460 			rs->requested_bitmap_chunk_sectors = value;
1461 		} else if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_RAID10_COPIES))) {
1462 			if (test_and_set_bit(__CTR_FLAG_RAID10_COPIES, &rs->ctr_flags)) {
1463 				rs->ti->error = "Only one raid10_copies argument pair allowed";
1464 				return -EINVAL;
1465 			}
1466 
1467 			if (!__within_range(value, 2, rs->md.raid_disks)) {
1468 				rs->ti->error = "Bad value for 'raid10_copies'";
1469 				return -EINVAL;
1470 			}
1471 
1472 			raid10_copies = value;
1473 		} else {
1474 			DMERR("Unable to parse RAID parameter: %s", key);
1475 			rs->ti->error = "Unable to parse RAID parameter";
1476 			return -EINVAL;
1477 		}
1478 	}
1479 
1480 	if (test_bit(__CTR_FLAG_SYNC, &rs->ctr_flags) &&
1481 	    test_bit(__CTR_FLAG_NOSYNC, &rs->ctr_flags)) {
1482 		rs->ti->error = "sync and nosync are mutually exclusive";
1483 		return -EINVAL;
1484 	}
1485 
1486 	if (test_bit(__CTR_FLAG_REBUILD, &rs->ctr_flags) &&
1487 	    (test_bit(__CTR_FLAG_SYNC, &rs->ctr_flags) ||
1488 	     test_bit(__CTR_FLAG_NOSYNC, &rs->ctr_flags))) {
1489 		rs->ti->error = "sync/nosync and rebuild are mutually exclusive";
1490 		return -EINVAL;
1491 	}
1492 
1493 	if (write_mostly >= rs->md.raid_disks) {
1494 		rs->ti->error = "Can't set all raid1 devices to write_mostly";
1495 		return -EINVAL;
1496 	}
1497 
1498 	if (rs->md.sync_speed_max &&
1499 	    rs->md.sync_speed_min > rs->md.sync_speed_max) {
1500 		rs->ti->error = "Bogus recovery rates";
1501 		return -EINVAL;
1502 	}
1503 
1504 	if (validate_region_size(rs, region_size))
1505 		return -EINVAL;
1506 
1507 	if (rs->md.chunk_sectors)
1508 		max_io_len = rs->md.chunk_sectors;
1509 	else
1510 		max_io_len = region_size;
1511 
1512 	if (dm_set_target_max_io_len(rs->ti, max_io_len))
1513 		return -EINVAL;
1514 
1515 	if (rt_is_raid10(rt)) {
1516 		if (raid10_copies > rs->md.raid_disks) {
1517 			rs->ti->error = "Not enough devices to satisfy specification";
1518 			return -EINVAL;
1519 		}
1520 
1521 		rs->md.new_layout = raid10_format_to_md_layout(rs, raid10_format, raid10_copies);
1522 		if (rs->md.new_layout < 0) {
1523 			rs->ti->error = "Error getting raid10 format";
1524 			return rs->md.new_layout;
1525 		}
1526 
1527 		rt = get_raid_type_by_ll(10, rs->md.new_layout);
1528 		if (!rt) {
1529 			rs->ti->error = "Failed to recognize new raid10 layout";
1530 			return -EINVAL;
1531 		}
1532 
1533 		if ((rt->algorithm == ALGORITHM_RAID10_DEFAULT ||
1534 		     rt->algorithm == ALGORITHM_RAID10_NEAR) &&
1535 		    test_bit(__CTR_FLAG_RAID10_USE_NEAR_SETS, &rs->ctr_flags)) {
1536 			rs->ti->error = "RAID10 format 'near' and 'raid10_use_near_sets' are incompatible";
1537 			return -EINVAL;
1538 		}
1539 	}
1540 
1541 	rs->raid10_copies = raid10_copies;
1542 
1543 	/* Assume there are no metadata devices until the drives are parsed */
1544 	rs->md.persistent = 0;
1545 	rs->md.external = 1;
1546 
1547 	/* Check, if any invalid ctr arguments have been passed in for the raid level */
1548 	return rs_check_for_valid_flags(rs);
1549 }
1550 
1551 /* Set raid4/5/6 cache size */
1552 static int rs_set_raid456_stripe_cache(struct raid_set *rs)
1553 {
1554 	int r;
1555 	struct r5conf *conf;
1556 	struct mddev *mddev = &rs->md;
1557 	uint32_t min_stripes = max(mddev->chunk_sectors, mddev->new_chunk_sectors) / 2;
1558 	uint32_t nr_stripes = rs->stripe_cache_entries;
1559 
1560 	if (!rt_is_raid456(rs->raid_type)) {
1561 		rs->ti->error = "Inappropriate raid level; cannot change stripe_cache size";
1562 		return -EINVAL;
1563 	}
1564 
1565 	if (nr_stripes < min_stripes) {
1566 		DMINFO("Adjusting requested %u stripe cache entries to %u to suit stripe size",
1567 		       nr_stripes, min_stripes);
1568 		nr_stripes = min_stripes;
1569 	}
1570 
1571 	conf = mddev->private;
1572 	if (!conf) {
1573 		rs->ti->error = "Cannot change stripe_cache size on inactive RAID set";
1574 		return -EINVAL;
1575 	}
1576 
1577 	/* Try setting number of stripes in raid456 stripe cache */
1578 	if (conf->min_nr_stripes != nr_stripes) {
1579 		r = raid5_set_cache_size(mddev, nr_stripes);
1580 		if (r) {
1581 			rs->ti->error = "Failed to set raid4/5/6 stripe cache size";
1582 			return r;
1583 		}
1584 
1585 		DMINFO("%u stripe cache entries", nr_stripes);
1586 	}
1587 
1588 	return 0;
1589 }
1590 
1591 /* Return # of data stripes as kept in mddev as of @rs (i.e. as of superblock) */
1592 static unsigned int mddev_data_stripes(struct raid_set *rs)
1593 {
1594 	return rs->md.raid_disks - rs->raid_type->parity_devs;
1595 }
1596 
1597 /* Return # of data stripes of @rs (i.e. as of ctr) */
1598 static unsigned int rs_data_stripes(struct raid_set *rs)
1599 {
1600 	return rs->raid_disks - rs->raid_type->parity_devs;
1601 }
1602 
1603 /*
1604  * Retrieve rdev->sectors from any valid raid device of @rs
1605  * to allow userpace to pass in arbitray "- -" device tupples.
1606  */
1607 static sector_t __rdev_sectors(struct raid_set *rs)
1608 {
1609 	int i;
1610 
1611 	for (i = 0; i < rs->md.raid_disks; i++) {
1612 		struct md_rdev *rdev = &rs->dev[i].rdev;
1613 
1614 		if (!test_bit(Journal, &rdev->flags) &&
1615 		    rdev->bdev && rdev->sectors)
1616 			return rdev->sectors;
1617 	}
1618 
1619 	return 0;
1620 }
1621 
1622 /* Check that calculated dev_sectors fits all component devices. */
1623 static int _check_data_dev_sectors(struct raid_set *rs)
1624 {
1625 	sector_t ds = ~0;
1626 	struct md_rdev *rdev;
1627 
1628 	rdev_for_each(rdev, &rs->md)
1629 		if (!test_bit(Journal, &rdev->flags) && rdev->bdev) {
1630 			ds = min(ds, to_sector(i_size_read(rdev->bdev->bd_inode)));
1631 			if (ds < rs->md.dev_sectors) {
1632 				rs->ti->error = "Component device(s) too small";
1633 				return -EINVAL;
1634 			}
1635 		}
1636 
1637 	return 0;
1638 }
1639 
1640 /* Calculate the sectors per device and per array used for @rs */
1641 static int rs_set_dev_and_array_sectors(struct raid_set *rs, bool use_mddev)
1642 {
1643 	int delta_disks;
1644 	unsigned int data_stripes;
1645 	struct mddev *mddev = &rs->md;
1646 	struct md_rdev *rdev;
1647 	sector_t array_sectors = rs->ti->len, dev_sectors = rs->ti->len;
1648 
1649 	if (use_mddev) {
1650 		delta_disks = mddev->delta_disks;
1651 		data_stripes = mddev_data_stripes(rs);
1652 	} else {
1653 		delta_disks = rs->delta_disks;
1654 		data_stripes = rs_data_stripes(rs);
1655 	}
1656 
1657 	/* Special raid1 case w/o delta_disks support (yet) */
1658 	if (rt_is_raid1(rs->raid_type))
1659 		;
1660 	else if (rt_is_raid10(rs->raid_type)) {
1661 		if (rs->raid10_copies < 2 ||
1662 		    delta_disks < 0) {
1663 			rs->ti->error = "Bogus raid10 data copies or delta disks";
1664 			return -EINVAL;
1665 		}
1666 
1667 		dev_sectors *= rs->raid10_copies;
1668 		if (sector_div(dev_sectors, data_stripes))
1669 			goto bad;
1670 
1671 		array_sectors = (data_stripes + delta_disks) * dev_sectors;
1672 		if (sector_div(array_sectors, rs->raid10_copies))
1673 			goto bad;
1674 
1675 	} else if (sector_div(dev_sectors, data_stripes))
1676 		goto bad;
1677 
1678 	else
1679 		/* Striped layouts */
1680 		array_sectors = (data_stripes + delta_disks) * dev_sectors;
1681 
1682 	rdev_for_each(rdev, mddev)
1683 		if (!test_bit(Journal, &rdev->flags))
1684 			rdev->sectors = dev_sectors;
1685 
1686 	mddev->array_sectors = array_sectors;
1687 	mddev->dev_sectors = dev_sectors;
1688 
1689 	return _check_data_dev_sectors(rs);
1690 bad:
1691 	rs->ti->error = "Target length not divisible by number of data devices";
1692 	return -EINVAL;
1693 }
1694 
1695 /* Setup recovery on @rs */
1696 static void __rs_setup_recovery(struct raid_set *rs, sector_t dev_sectors)
1697 {
1698 	/* raid0 does not recover */
1699 	if (rs_is_raid0(rs))
1700 		rs->md.recovery_cp = MaxSector;
1701 	/*
1702 	 * A raid6 set has to be recovered either
1703 	 * completely or for the grown part to
1704 	 * ensure proper parity and Q-Syndrome
1705 	 */
1706 	else if (rs_is_raid6(rs))
1707 		rs->md.recovery_cp = dev_sectors;
1708 	/*
1709 	 * Other raid set types may skip recovery
1710 	 * depending on the 'nosync' flag.
1711 	 */
1712 	else
1713 		rs->md.recovery_cp = test_bit(__CTR_FLAG_NOSYNC, &rs->ctr_flags)
1714 				     ? MaxSector : dev_sectors;
1715 }
1716 
1717 /* Setup recovery on @rs based on raid type, device size and 'nosync' flag */
1718 static void rs_setup_recovery(struct raid_set *rs, sector_t dev_sectors)
1719 {
1720 	if (!dev_sectors)
1721 		/* New raid set or 'sync' flag provided */
1722 		__rs_setup_recovery(rs, 0);
1723 	else if (dev_sectors == MaxSector)
1724 		/* Prevent recovery */
1725 		__rs_setup_recovery(rs, MaxSector);
1726 	else if (__rdev_sectors(rs) < dev_sectors)
1727 		/* Grown raid set */
1728 		__rs_setup_recovery(rs, __rdev_sectors(rs));
1729 	else
1730 		__rs_setup_recovery(rs, MaxSector);
1731 }
1732 
1733 static void do_table_event(struct work_struct *ws)
1734 {
1735 	struct raid_set *rs = container_of(ws, struct raid_set, md.event_work);
1736 
1737 	smp_rmb(); /* Make sure we access most actual mddev properties */
1738 	if (!rs_is_reshaping(rs)) {
1739 		if (rs_is_raid10(rs))
1740 			rs_set_rdev_sectors(rs);
1741 		rs_set_capacity(rs);
1742 	}
1743 	dm_table_event(rs->ti->table);
1744 }
1745 
1746 static int raid_is_congested(struct dm_target_callbacks *cb, int bits)
1747 {
1748 	struct raid_set *rs = container_of(cb, struct raid_set, callbacks);
1749 
1750 	return mddev_congested(&rs->md, bits);
1751 }
1752 
1753 /*
1754  * Make sure a valid takover (level switch) is being requested on @rs
1755  *
1756  * Conversions of raid sets from one MD personality to another
1757  * have to conform to restrictions which are enforced here.
1758  */
1759 static int rs_check_takeover(struct raid_set *rs)
1760 {
1761 	struct mddev *mddev = &rs->md;
1762 	unsigned int near_copies;
1763 
1764 	if (rs->md.degraded) {
1765 		rs->ti->error = "Can't takeover degraded raid set";
1766 		return -EPERM;
1767 	}
1768 
1769 	if (rs_is_reshaping(rs)) {
1770 		rs->ti->error = "Can't takeover reshaping raid set";
1771 		return -EPERM;
1772 	}
1773 
1774 	switch (mddev->level) {
1775 	case 0:
1776 		/* raid0 -> raid1/5 with one disk */
1777 		if ((mddev->new_level == 1 || mddev->new_level == 5) &&
1778 		    mddev->raid_disks == 1)
1779 			return 0;
1780 
1781 		/* raid0 -> raid10 */
1782 		if (mddev->new_level == 10 &&
1783 		    !(rs->raid_disks % mddev->raid_disks))
1784 			return 0;
1785 
1786 		/* raid0 with multiple disks -> raid4/5/6 */
1787 		if (__within_range(mddev->new_level, 4, 6) &&
1788 		    mddev->new_layout == ALGORITHM_PARITY_N &&
1789 		    mddev->raid_disks > 1)
1790 			return 0;
1791 
1792 		break;
1793 
1794 	case 10:
1795 		/* Can't takeover raid10_offset! */
1796 		if (__is_raid10_offset(mddev->layout))
1797 			break;
1798 
1799 		near_copies = __raid10_near_copies(mddev->layout);
1800 
1801 		/* raid10* -> raid0 */
1802 		if (mddev->new_level == 0) {
1803 			/* Can takeover raid10_near with raid disks divisable by data copies! */
1804 			if (near_copies > 1 &&
1805 			    !(mddev->raid_disks % near_copies)) {
1806 				mddev->raid_disks /= near_copies;
1807 				mddev->delta_disks = mddev->raid_disks;
1808 				return 0;
1809 			}
1810 
1811 			/* Can takeover raid10_far */
1812 			if (near_copies == 1 &&
1813 			    __raid10_far_copies(mddev->layout) > 1)
1814 				return 0;
1815 
1816 			break;
1817 		}
1818 
1819 		/* raid10_{near,far} -> raid1 */
1820 		if (mddev->new_level == 1 &&
1821 		    max(near_copies, __raid10_far_copies(mddev->layout)) == mddev->raid_disks)
1822 			return 0;
1823 
1824 		/* raid10_{near,far} with 2 disks -> raid4/5 */
1825 		if (__within_range(mddev->new_level, 4, 5) &&
1826 		    mddev->raid_disks == 2)
1827 			return 0;
1828 		break;
1829 
1830 	case 1:
1831 		/* raid1 with 2 disks -> raid4/5 */
1832 		if (__within_range(mddev->new_level, 4, 5) &&
1833 		    mddev->raid_disks == 2) {
1834 			mddev->degraded = 1;
1835 			return 0;
1836 		}
1837 
1838 		/* raid1 -> raid0 */
1839 		if (mddev->new_level == 0 &&
1840 		    mddev->raid_disks == 1)
1841 			return 0;
1842 
1843 		/* raid1 -> raid10 */
1844 		if (mddev->new_level == 10)
1845 			return 0;
1846 		break;
1847 
1848 	case 4:
1849 		/* raid4 -> raid0 */
1850 		if (mddev->new_level == 0)
1851 			return 0;
1852 
1853 		/* raid4 -> raid1/5 with 2 disks */
1854 		if ((mddev->new_level == 1 || mddev->new_level == 5) &&
1855 		    mddev->raid_disks == 2)
1856 			return 0;
1857 
1858 		/* raid4 -> raid5/6 with parity N */
1859 		if (__within_range(mddev->new_level, 5, 6) &&
1860 		    mddev->layout == ALGORITHM_PARITY_N)
1861 			return 0;
1862 		break;
1863 
1864 	case 5:
1865 		/* raid5 with parity N -> raid0 */
1866 		if (mddev->new_level == 0 &&
1867 		    mddev->layout == ALGORITHM_PARITY_N)
1868 			return 0;
1869 
1870 		/* raid5 with parity N -> raid4 */
1871 		if (mddev->new_level == 4 &&
1872 		    mddev->layout == ALGORITHM_PARITY_N)
1873 			return 0;
1874 
1875 		/* raid5 with 2 disks -> raid1/4/10 */
1876 		if ((mddev->new_level == 1 || mddev->new_level == 4 || mddev->new_level == 10) &&
1877 		    mddev->raid_disks == 2)
1878 			return 0;
1879 
1880 		/* raid5_* ->  raid6_*_6 with Q-Syndrome N (e.g. raid5_ra -> raid6_ra_6 */
1881 		if (mddev->new_level == 6 &&
1882 		    ((mddev->layout == ALGORITHM_PARITY_N && mddev->new_layout == ALGORITHM_PARITY_N) ||
1883 		      __within_range(mddev->new_layout, ALGORITHM_LEFT_ASYMMETRIC_6, ALGORITHM_RIGHT_SYMMETRIC_6)))
1884 			return 0;
1885 		break;
1886 
1887 	case 6:
1888 		/* raid6 with parity N -> raid0 */
1889 		if (mddev->new_level == 0 &&
1890 		    mddev->layout == ALGORITHM_PARITY_N)
1891 			return 0;
1892 
1893 		/* raid6 with parity N -> raid4 */
1894 		if (mddev->new_level == 4 &&
1895 		    mddev->layout == ALGORITHM_PARITY_N)
1896 			return 0;
1897 
1898 		/* raid6_*_n with Q-Syndrome N -> raid5_* */
1899 		if (mddev->new_level == 5 &&
1900 		    ((mddev->layout == ALGORITHM_PARITY_N && mddev->new_layout == ALGORITHM_PARITY_N) ||
1901 		     __within_range(mddev->new_layout, ALGORITHM_LEFT_ASYMMETRIC, ALGORITHM_RIGHT_SYMMETRIC)))
1902 			return 0;
1903 
1904 	default:
1905 		break;
1906 	}
1907 
1908 	rs->ti->error = "takeover not possible";
1909 	return -EINVAL;
1910 }
1911 
1912 /* True if @rs requested to be taken over */
1913 static bool rs_takeover_requested(struct raid_set *rs)
1914 {
1915 	return rs->md.new_level != rs->md.level;
1916 }
1917 
1918 /* True if @rs is requested to reshape by ctr */
1919 static bool rs_reshape_requested(struct raid_set *rs)
1920 {
1921 	bool change;
1922 	struct mddev *mddev = &rs->md;
1923 
1924 	if (rs_takeover_requested(rs))
1925 		return false;
1926 
1927 	if (rs_is_raid0(rs))
1928 		return false;
1929 
1930 	change = mddev->new_layout != mddev->layout ||
1931 		 mddev->new_chunk_sectors != mddev->chunk_sectors ||
1932 		 rs->delta_disks;
1933 
1934 	/* Historical case to support raid1 reshape without delta disks */
1935 	if (rs_is_raid1(rs)) {
1936 		if (rs->delta_disks)
1937 			return !!rs->delta_disks;
1938 
1939 		return !change &&
1940 		       mddev->raid_disks != rs->raid_disks;
1941 	}
1942 
1943 	if (rs_is_raid10(rs))
1944 		return change &&
1945 		       !__is_raid10_far(mddev->new_layout) &&
1946 		       rs->delta_disks >= 0;
1947 
1948 	return change;
1949 }
1950 
1951 /*  Features */
1952 #define	FEATURE_FLAG_SUPPORTS_V190	0x1 /* Supports extended superblock */
1953 
1954 /* State flags for sb->flags */
1955 #define	SB_FLAG_RESHAPE_ACTIVE		0x1
1956 #define	SB_FLAG_RESHAPE_BACKWARDS	0x2
1957 
1958 /*
1959  * This structure is never routinely used by userspace, unlike md superblocks.
1960  * Devices with this superblock should only ever be accessed via device-mapper.
1961  */
1962 #define DM_RAID_MAGIC 0x64526D44
1963 struct dm_raid_superblock {
1964 	__le32 magic;		/* "DmRd" */
1965 	__le32 compat_features;	/* Used to indicate compatible features (like 1.9.0 ondisk metadata extension) */
1966 
1967 	__le32 num_devices;	/* Number of devices in this raid set. (Max 64) */
1968 	__le32 array_position;	/* The position of this drive in the raid set */
1969 
1970 	__le64 events;		/* Incremented by md when superblock updated */
1971 	__le64 failed_devices;	/* Pre 1.9.0 part of bit field of devices to */
1972 				/* indicate failures (see extension below) */
1973 
1974 	/*
1975 	 * This offset tracks the progress of the repair or replacement of
1976 	 * an individual drive.
1977 	 */
1978 	__le64 disk_recovery_offset;
1979 
1980 	/*
1981 	 * This offset tracks the progress of the initial raid set
1982 	 * synchronisation/parity calculation.
1983 	 */
1984 	__le64 array_resync_offset;
1985 
1986 	/*
1987 	 * raid characteristics
1988 	 */
1989 	__le32 level;
1990 	__le32 layout;
1991 	__le32 stripe_sectors;
1992 
1993 	/********************************************************************
1994 	 * BELOW FOLLOW V1.9.0 EXTENSIONS TO THE PRISTINE SUPERBLOCK FORMAT!!!
1995 	 *
1996 	 * FEATURE_FLAG_SUPPORTS_V190 in the compat_features member indicates that those exist
1997 	 */
1998 
1999 	__le32 flags; /* Flags defining array states for reshaping */
2000 
2001 	/*
2002 	 * This offset tracks the progress of a raid
2003 	 * set reshape in order to be able to restart it
2004 	 */
2005 	__le64 reshape_position;
2006 
2007 	/*
2008 	 * These define the properties of the array in case of an interrupted reshape
2009 	 */
2010 	__le32 new_level;
2011 	__le32 new_layout;
2012 	__le32 new_stripe_sectors;
2013 	__le32 delta_disks;
2014 
2015 	__le64 array_sectors; /* Array size in sectors */
2016 
2017 	/*
2018 	 * Sector offsets to data on devices (reshaping).
2019 	 * Needed to support out of place reshaping, thus
2020 	 * not writing over any stripes whilst converting
2021 	 * them from old to new layout
2022 	 */
2023 	__le64 data_offset;
2024 	__le64 new_data_offset;
2025 
2026 	__le64 sectors; /* Used device size in sectors */
2027 
2028 	/*
2029 	 * Additonal Bit field of devices indicating failures to support
2030 	 * up to 256 devices with the 1.9.0 on-disk metadata format
2031 	 */
2032 	__le64 extended_failed_devices[DISKS_ARRAY_ELEMS - 1];
2033 
2034 	__le32 incompat_features;	/* Used to indicate any incompatible features */
2035 
2036 	/* Always set rest up to logical block size to 0 when writing (see get_metadata_device() below). */
2037 } __packed;
2038 
2039 /*
2040  * Check for reshape constraints on raid set @rs:
2041  *
2042  * - reshape function non-existent
2043  * - degraded set
2044  * - ongoing recovery
2045  * - ongoing reshape
2046  *
2047  * Returns 0 if none or -EPERM if given constraint
2048  * and error message reference in @errmsg
2049  */
2050 static int rs_check_reshape(struct raid_set *rs)
2051 {
2052 	struct mddev *mddev = &rs->md;
2053 
2054 	if (!mddev->pers || !mddev->pers->check_reshape)
2055 		rs->ti->error = "Reshape not supported";
2056 	else if (mddev->degraded)
2057 		rs->ti->error = "Can't reshape degraded raid set";
2058 	else if (rs_is_recovering(rs))
2059 		rs->ti->error = "Convert request on recovering raid set prohibited";
2060 	else if (rs_is_reshaping(rs))
2061 		rs->ti->error = "raid set already reshaping!";
2062 	else if (!(rs_is_raid1(rs) || rs_is_raid10(rs) || rs_is_raid456(rs)))
2063 		rs->ti->error = "Reshaping only supported for raid1/4/5/6/10";
2064 	else
2065 		return 0;
2066 
2067 	return -EPERM;
2068 }
2069 
2070 static int read_disk_sb(struct md_rdev *rdev, int size, bool force_reload)
2071 {
2072 	BUG_ON(!rdev->sb_page);
2073 
2074 	if (rdev->sb_loaded && !force_reload)
2075 		return 0;
2076 
2077 	rdev->sb_loaded = 0;
2078 
2079 	if (!sync_page_io(rdev, 0, size, rdev->sb_page, REQ_OP_READ, 0, true)) {
2080 		DMERR("Failed to read superblock of device at position %d",
2081 		      rdev->raid_disk);
2082 		md_error(rdev->mddev, rdev);
2083 		set_bit(Faulty, &rdev->flags);
2084 		return -EIO;
2085 	}
2086 
2087 	rdev->sb_loaded = 1;
2088 
2089 	return 0;
2090 }
2091 
2092 static void sb_retrieve_failed_devices(struct dm_raid_superblock *sb, uint64_t *failed_devices)
2093 {
2094 	failed_devices[0] = le64_to_cpu(sb->failed_devices);
2095 	memset(failed_devices + 1, 0, sizeof(sb->extended_failed_devices));
2096 
2097 	if (le32_to_cpu(sb->compat_features) & FEATURE_FLAG_SUPPORTS_V190) {
2098 		int i = ARRAY_SIZE(sb->extended_failed_devices);
2099 
2100 		while (i--)
2101 			failed_devices[i+1] = le64_to_cpu(sb->extended_failed_devices[i]);
2102 	}
2103 }
2104 
2105 static void sb_update_failed_devices(struct dm_raid_superblock *sb, uint64_t *failed_devices)
2106 {
2107 	int i = ARRAY_SIZE(sb->extended_failed_devices);
2108 
2109 	sb->failed_devices = cpu_to_le64(failed_devices[0]);
2110 	while (i--)
2111 		sb->extended_failed_devices[i] = cpu_to_le64(failed_devices[i+1]);
2112 }
2113 
2114 /*
2115  * Synchronize the superblock members with the raid set properties
2116  *
2117  * All superblock data is little endian.
2118  */
2119 static void super_sync(struct mddev *mddev, struct md_rdev *rdev)
2120 {
2121 	bool update_failed_devices = false;
2122 	unsigned int i;
2123 	uint64_t failed_devices[DISKS_ARRAY_ELEMS];
2124 	struct dm_raid_superblock *sb;
2125 	struct raid_set *rs = container_of(mddev, struct raid_set, md);
2126 
2127 	/* No metadata device, no superblock */
2128 	if (!rdev->meta_bdev)
2129 		return;
2130 
2131 	BUG_ON(!rdev->sb_page);
2132 
2133 	sb = page_address(rdev->sb_page);
2134 
2135 	sb_retrieve_failed_devices(sb, failed_devices);
2136 
2137 	for (i = 0; i < rs->raid_disks; i++)
2138 		if (!rs->dev[i].data_dev || test_bit(Faulty, &rs->dev[i].rdev.flags)) {
2139 			update_failed_devices = true;
2140 			set_bit(i, (void *) failed_devices);
2141 		}
2142 
2143 	if (update_failed_devices)
2144 		sb_update_failed_devices(sb, failed_devices);
2145 
2146 	sb->magic = cpu_to_le32(DM_RAID_MAGIC);
2147 	sb->compat_features = cpu_to_le32(FEATURE_FLAG_SUPPORTS_V190);
2148 
2149 	sb->num_devices = cpu_to_le32(mddev->raid_disks);
2150 	sb->array_position = cpu_to_le32(rdev->raid_disk);
2151 
2152 	sb->events = cpu_to_le64(mddev->events);
2153 
2154 	sb->disk_recovery_offset = cpu_to_le64(rdev->recovery_offset);
2155 	sb->array_resync_offset = cpu_to_le64(mddev->recovery_cp);
2156 
2157 	sb->level = cpu_to_le32(mddev->level);
2158 	sb->layout = cpu_to_le32(mddev->layout);
2159 	sb->stripe_sectors = cpu_to_le32(mddev->chunk_sectors);
2160 
2161 	/********************************************************************
2162 	 * BELOW FOLLOW V1.9.0 EXTENSIONS TO THE PRISTINE SUPERBLOCK FORMAT!!!
2163 	 *
2164 	 * FEATURE_FLAG_SUPPORTS_V190 in the compat_features member indicates that those exist
2165 	 */
2166 	sb->new_level = cpu_to_le32(mddev->new_level);
2167 	sb->new_layout = cpu_to_le32(mddev->new_layout);
2168 	sb->new_stripe_sectors = cpu_to_le32(mddev->new_chunk_sectors);
2169 
2170 	sb->delta_disks = cpu_to_le32(mddev->delta_disks);
2171 
2172 	smp_rmb(); /* Make sure we access most recent reshape position */
2173 	sb->reshape_position = cpu_to_le64(mddev->reshape_position);
2174 	if (le64_to_cpu(sb->reshape_position) != MaxSector) {
2175 		/* Flag ongoing reshape */
2176 		sb->flags |= cpu_to_le32(SB_FLAG_RESHAPE_ACTIVE);
2177 
2178 		if (mddev->delta_disks < 0 || mddev->reshape_backwards)
2179 			sb->flags |= cpu_to_le32(SB_FLAG_RESHAPE_BACKWARDS);
2180 	} else {
2181 		/* Clear reshape flags */
2182 		sb->flags &= ~(cpu_to_le32(SB_FLAG_RESHAPE_ACTIVE|SB_FLAG_RESHAPE_BACKWARDS));
2183 	}
2184 
2185 	sb->array_sectors = cpu_to_le64(mddev->array_sectors);
2186 	sb->data_offset = cpu_to_le64(rdev->data_offset);
2187 	sb->new_data_offset = cpu_to_le64(rdev->new_data_offset);
2188 	sb->sectors = cpu_to_le64(rdev->sectors);
2189 	sb->incompat_features = cpu_to_le32(0);
2190 
2191 	/* Zero out the rest of the payload after the size of the superblock */
2192 	memset(sb + 1, 0, rdev->sb_size - sizeof(*sb));
2193 }
2194 
2195 /*
2196  * super_load
2197  *
2198  * This function creates a superblock if one is not found on the device
2199  * and will decide which superblock to use if there's a choice.
2200  *
2201  * Return: 1 if use rdev, 0 if use refdev, -Exxx otherwise
2202  */
2203 static int super_load(struct md_rdev *rdev, struct md_rdev *refdev)
2204 {
2205 	int r;
2206 	struct dm_raid_superblock *sb;
2207 	struct dm_raid_superblock *refsb;
2208 	uint64_t events_sb, events_refsb;
2209 
2210 	r = read_disk_sb(rdev, rdev->sb_size, false);
2211 	if (r)
2212 		return r;
2213 
2214 	sb = page_address(rdev->sb_page);
2215 
2216 	/*
2217 	 * Two cases that we want to write new superblocks and rebuild:
2218 	 * 1) New device (no matching magic number)
2219 	 * 2) Device specified for rebuild (!In_sync w/ offset == 0)
2220 	 */
2221 	if ((sb->magic != cpu_to_le32(DM_RAID_MAGIC)) ||
2222 	    (!test_bit(In_sync, &rdev->flags) && !rdev->recovery_offset)) {
2223 		super_sync(rdev->mddev, rdev);
2224 
2225 		set_bit(FirstUse, &rdev->flags);
2226 		sb->compat_features = cpu_to_le32(FEATURE_FLAG_SUPPORTS_V190);
2227 
2228 		/* Force writing of superblocks to disk */
2229 		set_bit(MD_SB_CHANGE_DEVS, &rdev->mddev->sb_flags);
2230 
2231 		/* Any superblock is better than none, choose that if given */
2232 		return refdev ? 0 : 1;
2233 	}
2234 
2235 	if (!refdev)
2236 		return 1;
2237 
2238 	events_sb = le64_to_cpu(sb->events);
2239 
2240 	refsb = page_address(refdev->sb_page);
2241 	events_refsb = le64_to_cpu(refsb->events);
2242 
2243 	return (events_sb > events_refsb) ? 1 : 0;
2244 }
2245 
2246 static int super_init_validation(struct raid_set *rs, struct md_rdev *rdev)
2247 {
2248 	int role;
2249 	unsigned int d;
2250 	struct mddev *mddev = &rs->md;
2251 	uint64_t events_sb;
2252 	uint64_t failed_devices[DISKS_ARRAY_ELEMS];
2253 	struct dm_raid_superblock *sb;
2254 	uint32_t new_devs = 0, rebuild_and_new = 0, rebuilds = 0;
2255 	struct md_rdev *r;
2256 	struct dm_raid_superblock *sb2;
2257 
2258 	sb = page_address(rdev->sb_page);
2259 	events_sb = le64_to_cpu(sb->events);
2260 
2261 	/*
2262 	 * Initialise to 1 if this is a new superblock.
2263 	 */
2264 	mddev->events = events_sb ? : 1;
2265 
2266 	mddev->reshape_position = MaxSector;
2267 
2268 	mddev->raid_disks = le32_to_cpu(sb->num_devices);
2269 	mddev->level = le32_to_cpu(sb->level);
2270 	mddev->layout = le32_to_cpu(sb->layout);
2271 	mddev->chunk_sectors = le32_to_cpu(sb->stripe_sectors);
2272 
2273 	/*
2274 	 * Reshaping is supported, e.g. reshape_position is valid
2275 	 * in superblock and superblock content is authoritative.
2276 	 */
2277 	if (le32_to_cpu(sb->compat_features) & FEATURE_FLAG_SUPPORTS_V190) {
2278 		/* Superblock is authoritative wrt given raid set layout! */
2279 		mddev->new_level = le32_to_cpu(sb->new_level);
2280 		mddev->new_layout = le32_to_cpu(sb->new_layout);
2281 		mddev->new_chunk_sectors = le32_to_cpu(sb->new_stripe_sectors);
2282 		mddev->delta_disks = le32_to_cpu(sb->delta_disks);
2283 		mddev->array_sectors = le64_to_cpu(sb->array_sectors);
2284 
2285 		/* raid was reshaping and got interrupted */
2286 		if (le32_to_cpu(sb->flags) & SB_FLAG_RESHAPE_ACTIVE) {
2287 			if (test_bit(__CTR_FLAG_DELTA_DISKS, &rs->ctr_flags)) {
2288 				DMERR("Reshape requested but raid set is still reshaping");
2289 				return -EINVAL;
2290 			}
2291 
2292 			if (mddev->delta_disks < 0 ||
2293 			    (!mddev->delta_disks && (le32_to_cpu(sb->flags) & SB_FLAG_RESHAPE_BACKWARDS)))
2294 				mddev->reshape_backwards = 1;
2295 			else
2296 				mddev->reshape_backwards = 0;
2297 
2298 			mddev->reshape_position = le64_to_cpu(sb->reshape_position);
2299 			rs->raid_type = get_raid_type_by_ll(mddev->level, mddev->layout);
2300 		}
2301 
2302 	} else {
2303 		/*
2304 		 * No takeover/reshaping, because we don't have the extended v1.9.0 metadata
2305 		 */
2306 		struct raid_type *rt_cur = get_raid_type_by_ll(mddev->level, mddev->layout);
2307 		struct raid_type *rt_new = get_raid_type_by_ll(mddev->new_level, mddev->new_layout);
2308 
2309 		if (rs_takeover_requested(rs)) {
2310 			if (rt_cur && rt_new)
2311 				DMERR("Takeover raid sets from %s to %s not yet supported by metadata. (raid level change)",
2312 				      rt_cur->name, rt_new->name);
2313 			else
2314 				DMERR("Takeover raid sets not yet supported by metadata. (raid level change)");
2315 			return -EINVAL;
2316 		} else if (rs_reshape_requested(rs)) {
2317 			DMERR("Reshaping raid sets not yet supported by metadata. (raid layout change keeping level)");
2318 			if (mddev->layout != mddev->new_layout) {
2319 				if (rt_cur && rt_new)
2320 					DMERR("	 current layout %s vs new layout %s",
2321 					      rt_cur->name, rt_new->name);
2322 				else
2323 					DMERR("	 current layout 0x%X vs new layout 0x%X",
2324 					      le32_to_cpu(sb->layout), mddev->new_layout);
2325 			}
2326 			if (mddev->chunk_sectors != mddev->new_chunk_sectors)
2327 				DMERR("	 current stripe sectors %u vs new stripe sectors %u",
2328 				      mddev->chunk_sectors, mddev->new_chunk_sectors);
2329 			if (rs->delta_disks)
2330 				DMERR("	 current %u disks vs new %u disks",
2331 				      mddev->raid_disks, mddev->raid_disks + rs->delta_disks);
2332 			if (rs_is_raid10(rs)) {
2333 				DMERR("	 Old layout: %s w/ %u copies",
2334 				      raid10_md_layout_to_format(mddev->layout),
2335 				      raid10_md_layout_to_copies(mddev->layout));
2336 				DMERR("	 New layout: %s w/ %u copies",
2337 				      raid10_md_layout_to_format(mddev->new_layout),
2338 				      raid10_md_layout_to_copies(mddev->new_layout));
2339 			}
2340 			return -EINVAL;
2341 		}
2342 
2343 		DMINFO("Discovered old metadata format; upgrading to extended metadata format");
2344 	}
2345 
2346 	if (!test_bit(__CTR_FLAG_NOSYNC, &rs->ctr_flags))
2347 		mddev->recovery_cp = le64_to_cpu(sb->array_resync_offset);
2348 
2349 	/*
2350 	 * During load, we set FirstUse if a new superblock was written.
2351 	 * There are two reasons we might not have a superblock:
2352 	 * 1) The raid set is brand new - in which case, all of the
2353 	 *    devices must have their In_sync bit set.	Also,
2354 	 *    recovery_cp must be 0, unless forced.
2355 	 * 2) This is a new device being added to an old raid set
2356 	 *    and the new device needs to be rebuilt - in which
2357 	 *    case the In_sync bit will /not/ be set and
2358 	 *    recovery_cp must be MaxSector.
2359 	 * 3) This is/are a new device(s) being added to an old
2360 	 *    raid set during takeover to a higher raid level
2361 	 *    to provide capacity for redundancy or during reshape
2362 	 *    to add capacity to grow the raid set.
2363 	 */
2364 	d = 0;
2365 	rdev_for_each(r, mddev) {
2366 		if (test_bit(Journal, &rdev->flags))
2367 			continue;
2368 
2369 		if (test_bit(FirstUse, &r->flags))
2370 			new_devs++;
2371 
2372 		if (!test_bit(In_sync, &r->flags)) {
2373 			DMINFO("Device %d specified for rebuild; clearing superblock",
2374 				r->raid_disk);
2375 			rebuilds++;
2376 
2377 			if (test_bit(FirstUse, &r->flags))
2378 				rebuild_and_new++;
2379 		}
2380 
2381 		d++;
2382 	}
2383 
2384 	if (new_devs == rs->raid_disks || !rebuilds) {
2385 		/* Replace a broken device */
2386 		if (new_devs == 1 && !rs->delta_disks)
2387 			;
2388 		if (new_devs == rs->raid_disks) {
2389 			DMINFO("Superblocks created for new raid set");
2390 			set_bit(MD_ARRAY_FIRST_USE, &mddev->flags);
2391 		} else if (new_devs != rebuilds &&
2392 			   new_devs != rs->delta_disks) {
2393 			DMERR("New device injected into existing raid set without "
2394 			      "'delta_disks' or 'rebuild' parameter specified");
2395 			return -EINVAL;
2396 		}
2397 	} else if (new_devs && new_devs != rebuilds) {
2398 		DMERR("%u 'rebuild' devices cannot be injected into"
2399 		      " a raid set with %u other first-time devices",
2400 		      rebuilds, new_devs);
2401 		return -EINVAL;
2402 	} else if (rebuilds) {
2403 		if (rebuild_and_new && rebuilds != rebuild_and_new) {
2404 			DMERR("new device%s provided without 'rebuild'",
2405 			      new_devs > 1 ? "s" : "");
2406 			return -EINVAL;
2407 		} else if (!test_bit(__CTR_FLAG_REBUILD, &rs->ctr_flags) && rs_is_recovering(rs)) {
2408 			DMERR("'rebuild' specified while raid set is not in-sync (recovery_cp=%llu)",
2409 			      (unsigned long long) mddev->recovery_cp);
2410 			return -EINVAL;
2411 		} else if (rs_is_reshaping(rs)) {
2412 			DMERR("'rebuild' specified while raid set is being reshaped (reshape_position=%llu)",
2413 			      (unsigned long long) mddev->reshape_position);
2414 			return -EINVAL;
2415 		}
2416 	}
2417 
2418 	/*
2419 	 * Now we set the Faulty bit for those devices that are
2420 	 * recorded in the superblock as failed.
2421 	 */
2422 	sb_retrieve_failed_devices(sb, failed_devices);
2423 	rdev_for_each(r, mddev) {
2424 		if (test_bit(Journal, &rdev->flags) ||
2425 		    !r->sb_page)
2426 			continue;
2427 		sb2 = page_address(r->sb_page);
2428 		sb2->failed_devices = 0;
2429 		memset(sb2->extended_failed_devices, 0, sizeof(sb2->extended_failed_devices));
2430 
2431 		/*
2432 		 * Check for any device re-ordering.
2433 		 */
2434 		if (!test_bit(FirstUse, &r->flags) && (r->raid_disk >= 0)) {
2435 			role = le32_to_cpu(sb2->array_position);
2436 			if (role < 0)
2437 				continue;
2438 
2439 			if (role != r->raid_disk) {
2440 				if (rs_is_raid10(rs) && __is_raid10_near(mddev->layout)) {
2441 					if (mddev->raid_disks % __raid10_near_copies(mddev->layout) ||
2442 					    rs->raid_disks % rs->raid10_copies) {
2443 						rs->ti->error =
2444 							"Cannot change raid10 near set to odd # of devices!";
2445 						return -EINVAL;
2446 					}
2447 
2448 					sb2->array_position = cpu_to_le32(r->raid_disk);
2449 
2450 				} else if (!(rs_is_raid10(rs) && rt_is_raid0(rs->raid_type)) &&
2451 					   !(rs_is_raid0(rs) && rt_is_raid10(rs->raid_type)) &&
2452 					   !rt_is_raid1(rs->raid_type)) {
2453 					rs->ti->error = "Cannot change device positions in raid set";
2454 					return -EINVAL;
2455 				}
2456 
2457 				DMINFO("raid device #%d now at position #%d", role, r->raid_disk);
2458 			}
2459 
2460 			/*
2461 			 * Partial recovery is performed on
2462 			 * returning failed devices.
2463 			 */
2464 			if (test_bit(role, (void *) failed_devices))
2465 				set_bit(Faulty, &r->flags);
2466 		}
2467 	}
2468 
2469 	return 0;
2470 }
2471 
2472 static int super_validate(struct raid_set *rs, struct md_rdev *rdev)
2473 {
2474 	struct mddev *mddev = &rs->md;
2475 	struct dm_raid_superblock *sb;
2476 
2477 	if (rs_is_raid0(rs) || !rdev->sb_page || rdev->raid_disk < 0)
2478 		return 0;
2479 
2480 	sb = page_address(rdev->sb_page);
2481 
2482 	/*
2483 	 * If mddev->events is not set, we know we have not yet initialized
2484 	 * the array.
2485 	 */
2486 	if (!mddev->events && super_init_validation(rs, rdev))
2487 		return -EINVAL;
2488 
2489 	if (le32_to_cpu(sb->compat_features) &&
2490 	    le32_to_cpu(sb->compat_features) != FEATURE_FLAG_SUPPORTS_V190) {
2491 		rs->ti->error = "Unable to assemble array: Unknown flag(s) in compatible feature flags";
2492 		return -EINVAL;
2493 	}
2494 
2495 	if (sb->incompat_features) {
2496 		rs->ti->error = "Unable to assemble array: No incompatible feature flags supported yet";
2497 		return -EINVAL;
2498 	}
2499 
2500 	/* Enable bitmap creation for RAID levels != 0 */
2501 	mddev->bitmap_info.offset = rt_is_raid0(rs->raid_type) ? 0 : to_sector(4096);
2502 	mddev->bitmap_info.default_offset = mddev->bitmap_info.offset;
2503 
2504 	if (!test_and_clear_bit(FirstUse, &rdev->flags)) {
2505 		/*
2506 		 * Retrieve rdev size stored in superblock to be prepared for shrink.
2507 		 * Check extended superblock members are present otherwise the size
2508 		 * will not be set!
2509 		 */
2510 		if (le32_to_cpu(sb->compat_features) & FEATURE_FLAG_SUPPORTS_V190)
2511 			rdev->sectors = le64_to_cpu(sb->sectors);
2512 
2513 		rdev->recovery_offset = le64_to_cpu(sb->disk_recovery_offset);
2514 		if (rdev->recovery_offset == MaxSector)
2515 			set_bit(In_sync, &rdev->flags);
2516 		/*
2517 		 * If no reshape in progress -> we're recovering single
2518 		 * disk(s) and have to set the device(s) to out-of-sync
2519 		 */
2520 		else if (!rs_is_reshaping(rs))
2521 			clear_bit(In_sync, &rdev->flags); /* Mandatory for recovery */
2522 	}
2523 
2524 	/*
2525 	 * If a device comes back, set it as not In_sync and no longer faulty.
2526 	 */
2527 	if (test_and_clear_bit(Faulty, &rdev->flags)) {
2528 		rdev->recovery_offset = 0;
2529 		clear_bit(In_sync, &rdev->flags);
2530 		rdev->saved_raid_disk = rdev->raid_disk;
2531 	}
2532 
2533 	/* Reshape support -> restore repective data offsets */
2534 	rdev->data_offset = le64_to_cpu(sb->data_offset);
2535 	rdev->new_data_offset = le64_to_cpu(sb->new_data_offset);
2536 
2537 	return 0;
2538 }
2539 
2540 /*
2541  * Analyse superblocks and select the freshest.
2542  */
2543 static int analyse_superblocks(struct dm_target *ti, struct raid_set *rs)
2544 {
2545 	int r;
2546 	struct md_rdev *rdev, *freshest;
2547 	struct mddev *mddev = &rs->md;
2548 
2549 	freshest = NULL;
2550 	rdev_for_each(rdev, mddev) {
2551 		if (test_bit(Journal, &rdev->flags))
2552 			continue;
2553 
2554 		if (!rdev->meta_bdev)
2555 			continue;
2556 
2557 		/* Set superblock offset/size for metadata device. */
2558 		rdev->sb_start = 0;
2559 		rdev->sb_size = bdev_logical_block_size(rdev->meta_bdev);
2560 		if (rdev->sb_size < sizeof(struct dm_raid_superblock) || rdev->sb_size > PAGE_SIZE) {
2561 			DMERR("superblock size of a logical block is no longer valid");
2562 			return -EINVAL;
2563 		}
2564 
2565 		/*
2566 		 * Skipping super_load due to CTR_FLAG_SYNC will cause
2567 		 * the array to undergo initialization again as
2568 		 * though it were new.	This is the intended effect
2569 		 * of the "sync" directive.
2570 		 *
2571 		 * With reshaping capability added, we must ensure that
2572 		 * that the "sync" directive is disallowed during the reshape.
2573 		 */
2574 		if (test_bit(__CTR_FLAG_SYNC, &rs->ctr_flags))
2575 			continue;
2576 
2577 		r = super_load(rdev, freshest);
2578 
2579 		switch (r) {
2580 		case 1:
2581 			freshest = rdev;
2582 			break;
2583 		case 0:
2584 			break;
2585 		default:
2586 			/* This is a failure to read the superblock from the metadata device. */
2587 			/*
2588 			 * We have to keep any raid0 data/metadata device pairs or
2589 			 * the MD raid0 personality will fail to start the array.
2590 			 */
2591 			if (rs_is_raid0(rs))
2592 				continue;
2593 
2594 			/*
2595 			 * We keep the dm_devs to be able to emit the device tuple
2596 			 * properly on the table line in raid_status() (rather than
2597 			 * mistakenly acting as if '- -' got passed into the constructor).
2598 			 *
2599 			 * The rdev has to stay on the same_set list to allow for
2600 			 * the attempt to restore faulty devices on second resume.
2601 			 */
2602 			rdev->raid_disk = rdev->saved_raid_disk = -1;
2603 			break;
2604 		}
2605 	}
2606 
2607 	if (!freshest)
2608 		return 0;
2609 
2610 	/*
2611 	 * Validation of the freshest device provides the source of
2612 	 * validation for the remaining devices.
2613 	 */
2614 	rs->ti->error = "Unable to assemble array: Invalid superblocks";
2615 	if (super_validate(rs, freshest))
2616 		return -EINVAL;
2617 
2618 	if (validate_raid_redundancy(rs)) {
2619 		rs->ti->error = "Insufficient redundancy to activate array";
2620 		return -EINVAL;
2621 	}
2622 
2623 	rdev_for_each(rdev, mddev)
2624 		if (!test_bit(Journal, &rdev->flags) &&
2625 		    rdev != freshest &&
2626 		    super_validate(rs, rdev))
2627 			return -EINVAL;
2628 	return 0;
2629 }
2630 
2631 /*
2632  * Adjust data_offset and new_data_offset on all disk members of @rs
2633  * for out of place reshaping if requested by contructor
2634  *
2635  * We need free space at the beginning of each raid disk for forward
2636  * and at the end for backward reshapes which userspace has to provide
2637  * via remapping/reordering of space.
2638  */
2639 static int rs_adjust_data_offsets(struct raid_set *rs)
2640 {
2641 	sector_t data_offset = 0, new_data_offset = 0;
2642 	struct md_rdev *rdev;
2643 
2644 	/* Constructor did not request data offset change */
2645 	if (!test_bit(__CTR_FLAG_DATA_OFFSET, &rs->ctr_flags)) {
2646 		if (!rs_is_reshapable(rs))
2647 			goto out;
2648 
2649 		return 0;
2650 	}
2651 
2652 	/* HM FIXME: get InSync raid_dev? */
2653 	rdev = &rs->dev[0].rdev;
2654 
2655 	if (rs->delta_disks < 0) {
2656 		/*
2657 		 * Removing disks (reshaping backwards):
2658 		 *
2659 		 * - before reshape: data is at offset 0 and free space
2660 		 *		     is at end of each component LV
2661 		 *
2662 		 * - after reshape: data is at offset rs->data_offset != 0 on each component LV
2663 		 */
2664 		data_offset = 0;
2665 		new_data_offset = rs->data_offset;
2666 
2667 	} else if (rs->delta_disks > 0) {
2668 		/*
2669 		 * Adding disks (reshaping forwards):
2670 		 *
2671 		 * - before reshape: data is at offset rs->data_offset != 0 and
2672 		 *		     free space is at begin of each component LV
2673 		 *
2674 		 * - after reshape: data is at offset 0 on each component LV
2675 		 */
2676 		data_offset = rs->data_offset;
2677 		new_data_offset = 0;
2678 
2679 	} else {
2680 		/*
2681 		 * User space passes in 0 for data offset after having removed reshape space
2682 		 *
2683 		 * - or - (data offset != 0)
2684 		 *
2685 		 * Changing RAID layout or chunk size -> toggle offsets
2686 		 *
2687 		 * - before reshape: data is at offset rs->data_offset 0 and
2688 		 *		     free space is at end of each component LV
2689 		 *		     -or-
2690 		 *                   data is at offset rs->data_offset != 0 and
2691 		 *		     free space is at begin of each component LV
2692 		 *
2693 		 * - after reshape: data is at offset 0 if it was at offset != 0
2694 		 *                  or at offset != 0 if it was at offset 0
2695 		 *                  on each component LV
2696 		 *
2697 		 */
2698 		data_offset = rs->data_offset ? rdev->data_offset : 0;
2699 		new_data_offset = data_offset ? 0 : rs->data_offset;
2700 		set_bit(RT_FLAG_UPDATE_SBS, &rs->runtime_flags);
2701 	}
2702 
2703 	/*
2704 	 * Make sure we got a minimum amount of free sectors per device
2705 	 */
2706 	if (rs->data_offset &&
2707 	    to_sector(i_size_read(rdev->bdev->bd_inode)) - rs->md.dev_sectors < MIN_FREE_RESHAPE_SPACE) {
2708 		rs->ti->error = data_offset ? "No space for forward reshape" :
2709 					      "No space for backward reshape";
2710 		return -ENOSPC;
2711 	}
2712 out:
2713 	/*
2714 	 * Raise recovery_cp in case data_offset != 0 to
2715 	 * avoid false recovery positives in the constructor.
2716 	 */
2717 	if (rs->md.recovery_cp < rs->md.dev_sectors)
2718 		rs->md.recovery_cp += rs->dev[0].rdev.data_offset;
2719 
2720 	/* Adjust data offsets on all rdevs but on any raid4/5/6 journal device */
2721 	rdev_for_each(rdev, &rs->md) {
2722 		if (!test_bit(Journal, &rdev->flags)) {
2723 			rdev->data_offset = data_offset;
2724 			rdev->new_data_offset = new_data_offset;
2725 		}
2726 	}
2727 
2728 	return 0;
2729 }
2730 
2731 /* Userpace reordered disks -> adjust raid_disk indexes in @rs */
2732 static void __reorder_raid_disk_indexes(struct raid_set *rs)
2733 {
2734 	int i = 0;
2735 	struct md_rdev *rdev;
2736 
2737 	rdev_for_each(rdev, &rs->md) {
2738 		if (!test_bit(Journal, &rdev->flags)) {
2739 			rdev->raid_disk = i++;
2740 			rdev->saved_raid_disk = rdev->new_raid_disk = -1;
2741 		}
2742 	}
2743 }
2744 
2745 /*
2746  * Setup @rs for takeover by a different raid level
2747  */
2748 static int rs_setup_takeover(struct raid_set *rs)
2749 {
2750 	struct mddev *mddev = &rs->md;
2751 	struct md_rdev *rdev;
2752 	unsigned int d = mddev->raid_disks = rs->raid_disks;
2753 	sector_t new_data_offset = rs->dev[0].rdev.data_offset ? 0 : rs->data_offset;
2754 
2755 	if (rt_is_raid10(rs->raid_type)) {
2756 		if (rs_is_raid0(rs)) {
2757 			/* Userpace reordered disks -> adjust raid_disk indexes */
2758 			__reorder_raid_disk_indexes(rs);
2759 
2760 			/* raid0 -> raid10_far layout */
2761 			mddev->layout = raid10_format_to_md_layout(rs, ALGORITHM_RAID10_FAR,
2762 								   rs->raid10_copies);
2763 		} else if (rs_is_raid1(rs))
2764 			/* raid1 -> raid10_near layout */
2765 			mddev->layout = raid10_format_to_md_layout(rs, ALGORITHM_RAID10_NEAR,
2766 								   rs->raid_disks);
2767 		else
2768 			return -EINVAL;
2769 
2770 	}
2771 
2772 	clear_bit(MD_ARRAY_FIRST_USE, &mddev->flags);
2773 	mddev->recovery_cp = MaxSector;
2774 
2775 	while (d--) {
2776 		rdev = &rs->dev[d].rdev;
2777 
2778 		if (test_bit(d, (void *) rs->rebuild_disks)) {
2779 			clear_bit(In_sync, &rdev->flags);
2780 			clear_bit(Faulty, &rdev->flags);
2781 			mddev->recovery_cp = rdev->recovery_offset = 0;
2782 			/* Bitmap has to be created when we do an "up" takeover */
2783 			set_bit(MD_ARRAY_FIRST_USE, &mddev->flags);
2784 		}
2785 
2786 		rdev->new_data_offset = new_data_offset;
2787 	}
2788 
2789 	return 0;
2790 }
2791 
2792 /* Prepare @rs for reshape */
2793 static int rs_prepare_reshape(struct raid_set *rs)
2794 {
2795 	bool reshape;
2796 	struct mddev *mddev = &rs->md;
2797 
2798 	if (rs_is_raid10(rs)) {
2799 		if (rs->raid_disks != mddev->raid_disks &&
2800 		    __is_raid10_near(mddev->layout) &&
2801 		    rs->raid10_copies &&
2802 		    rs->raid10_copies != __raid10_near_copies(mddev->layout)) {
2803 			/*
2804 			 * raid disk have to be multiple of data copies to allow this conversion,
2805 			 *
2806 			 * This is actually not a reshape it is a
2807 			 * rebuild of any additional mirrors per group
2808 			 */
2809 			if (rs->raid_disks % rs->raid10_copies) {
2810 				rs->ti->error = "Can't reshape raid10 mirror groups";
2811 				return -EINVAL;
2812 			}
2813 
2814 			/* Userpace reordered disks to add/remove mirrors -> adjust raid_disk indexes */
2815 			__reorder_raid_disk_indexes(rs);
2816 			mddev->layout = raid10_format_to_md_layout(rs, ALGORITHM_RAID10_NEAR,
2817 								   rs->raid10_copies);
2818 			mddev->new_layout = mddev->layout;
2819 			reshape = false;
2820 		} else
2821 			reshape = true;
2822 
2823 	} else if (rs_is_raid456(rs))
2824 		reshape = true;
2825 
2826 	else if (rs_is_raid1(rs)) {
2827 		if (rs->delta_disks) {
2828 			/* Process raid1 via delta_disks */
2829 			mddev->degraded = rs->delta_disks < 0 ? -rs->delta_disks : rs->delta_disks;
2830 			reshape = true;
2831 		} else {
2832 			/* Process raid1 without delta_disks */
2833 			mddev->raid_disks = rs->raid_disks;
2834 			reshape = false;
2835 		}
2836 	} else {
2837 		rs->ti->error = "Called with bogus raid type";
2838 		return -EINVAL;
2839 	}
2840 
2841 	if (reshape) {
2842 		set_bit(RT_FLAG_RESHAPE_RS, &rs->runtime_flags);
2843 		set_bit(RT_FLAG_UPDATE_SBS, &rs->runtime_flags);
2844 	} else if (mddev->raid_disks < rs->raid_disks)
2845 		/* Create new superblocks and bitmaps, if any new disks */
2846 		set_bit(RT_FLAG_UPDATE_SBS, &rs->runtime_flags);
2847 
2848 	return 0;
2849 }
2850 
2851 /* Get reshape sectors from data_offsets or raid set */
2852 static sector_t _get_reshape_sectors(struct raid_set *rs)
2853 {
2854 	struct md_rdev *rdev;
2855 	sector_t reshape_sectors = 0;
2856 
2857 	rdev_for_each(rdev, &rs->md)
2858 		if (!test_bit(Journal, &rdev->flags)) {
2859 			reshape_sectors = (rdev->data_offset > rdev->new_data_offset) ?
2860 					rdev->data_offset - rdev->new_data_offset :
2861 					rdev->new_data_offset - rdev->data_offset;
2862 			break;
2863 		}
2864 
2865 	return max(reshape_sectors, (sector_t) rs->data_offset);
2866 }
2867 
2868 /*
2869  *
2870  * - change raid layout
2871  * - change chunk size
2872  * - add disks
2873  * - remove disks
2874  */
2875 static int rs_setup_reshape(struct raid_set *rs)
2876 {
2877 	int r = 0;
2878 	unsigned int cur_raid_devs, d;
2879 	sector_t reshape_sectors = _get_reshape_sectors(rs);
2880 	struct mddev *mddev = &rs->md;
2881 	struct md_rdev *rdev;
2882 
2883 	mddev->delta_disks = rs->delta_disks;
2884 	cur_raid_devs = mddev->raid_disks;
2885 
2886 	/* Ignore impossible layout change whilst adding/removing disks */
2887 	if (mddev->delta_disks &&
2888 	    mddev->layout != mddev->new_layout) {
2889 		DMINFO("Ignoring invalid layout change with delta_disks=%d", rs->delta_disks);
2890 		mddev->new_layout = mddev->layout;
2891 	}
2892 
2893 	/*
2894 	 * Adjust array size:
2895 	 *
2896 	 * - in case of adding disk(s), array size has
2897 	 *   to grow after the disk adding reshape,
2898 	 *   which'll hapen in the event handler;
2899 	 *   reshape will happen forward, so space has to
2900 	 *   be available at the beginning of each disk
2901 	 *
2902 	 * - in case of removing disk(s), array size
2903 	 *   has to shrink before starting the reshape,
2904 	 *   which'll happen here;
2905 	 *   reshape will happen backward, so space has to
2906 	 *   be available at the end of each disk
2907 	 *
2908 	 * - data_offset and new_data_offset are
2909 	 *   adjusted for aforementioned out of place
2910 	 *   reshaping based on userspace passing in
2911 	 *   the "data_offset <sectors>" key/value
2912 	 *   pair via the constructor
2913 	 */
2914 
2915 	/* Add disk(s) */
2916 	if (rs->delta_disks > 0) {
2917 		/* Prepare disks for check in raid4/5/6/10 {check|start}_reshape */
2918 		for (d = cur_raid_devs; d < rs->raid_disks; d++) {
2919 			rdev = &rs->dev[d].rdev;
2920 			clear_bit(In_sync, &rdev->flags);
2921 
2922 			/*
2923 			 * save_raid_disk needs to be -1, or recovery_offset will be set to 0
2924 			 * by md, which'll store that erroneously in the superblock on reshape
2925 			 */
2926 			rdev->saved_raid_disk = -1;
2927 			rdev->raid_disk = d;
2928 
2929 			rdev->sectors = mddev->dev_sectors;
2930 			rdev->recovery_offset = rs_is_raid1(rs) ? 0 : MaxSector;
2931 		}
2932 
2933 		mddev->reshape_backwards = 0; /* adding disk(s) -> forward reshape */
2934 
2935 	/* Remove disk(s) */
2936 	} else if (rs->delta_disks < 0) {
2937 		r = rs_set_dev_and_array_sectors(rs, true);
2938 		mddev->reshape_backwards = 1; /* removing disk(s) -> backward reshape */
2939 
2940 	/* Change layout and/or chunk size */
2941 	} else {
2942 		/*
2943 		 * Reshape layout (e.g. raid5_ls -> raid5_n) and/or chunk size:
2944 		 *
2945 		 * keeping number of disks and do layout change ->
2946 		 *
2947 		 * toggle reshape_backward depending on data_offset:
2948 		 *
2949 		 * - free space upfront -> reshape forward
2950 		 *
2951 		 * - free space at the end -> reshape backward
2952 		 *
2953 		 *
2954 		 * This utilizes free reshape space avoiding the need
2955 		 * for userspace to move (parts of) LV segments in
2956 		 * case of layout/chunksize change  (for disk
2957 		 * adding/removing reshape space has to be at
2958 		 * the proper address (see above with delta_disks):
2959 		 *
2960 		 * add disk(s)   -> begin
2961 		 * remove disk(s)-> end
2962 		 */
2963 		mddev->reshape_backwards = rs->dev[0].rdev.data_offset ? 0 : 1;
2964 	}
2965 
2966 	/*
2967 	 * Adjust device size for forward reshape
2968 	 * because md_finish_reshape() reduces it.
2969 	 */
2970 	if (!mddev->reshape_backwards)
2971 		rdev_for_each(rdev, &rs->md)
2972 			if (!test_bit(Journal, &rdev->flags))
2973 				rdev->sectors += reshape_sectors;
2974 
2975 	return r;
2976 }
2977 
2978 /*
2979  * Enable/disable discard support on RAID set depending on
2980  * RAID level and discard properties of underlying RAID members.
2981  */
2982 static void configure_discard_support(struct raid_set *rs)
2983 {
2984 	int i;
2985 	bool raid456;
2986 	struct dm_target *ti = rs->ti;
2987 
2988 	/*
2989 	 * XXX: RAID level 4,5,6 require zeroing for safety.
2990 	 */
2991 	raid456 = rs_is_raid456(rs);
2992 
2993 	for (i = 0; i < rs->raid_disks; i++) {
2994 		struct request_queue *q;
2995 
2996 		if (!rs->dev[i].rdev.bdev)
2997 			continue;
2998 
2999 		q = bdev_get_queue(rs->dev[i].rdev.bdev);
3000 		if (!q || !blk_queue_discard(q))
3001 			return;
3002 
3003 		if (raid456) {
3004 			if (!devices_handle_discard_safely) {
3005 				DMERR("raid456 discard support disabled due to discard_zeroes_data uncertainty.");
3006 				DMERR("Set dm-raid.devices_handle_discard_safely=Y to override.");
3007 				return;
3008 			}
3009 		}
3010 	}
3011 
3012 	/*
3013 	 * RAID1 and RAID10 personalities require bio splitting,
3014 	 * RAID0/4/5/6 don't and process large discard bios properly.
3015 	 */
3016 	ti->split_discard_bios = !!(rs_is_raid1(rs) || rs_is_raid10(rs));
3017 	ti->num_discard_bios = 1;
3018 }
3019 
3020 /*
3021  * Construct a RAID0/1/10/4/5/6 mapping:
3022  * Args:
3023  *	<raid_type> <#raid_params> <raid_params>{0,}	\
3024  *	<#raid_devs> [<meta_dev1> <dev1>]{1,}
3025  *
3026  * <raid_params> varies by <raid_type>.	 See 'parse_raid_params' for
3027  * details on possible <raid_params>.
3028  *
3029  * Userspace is free to initialize the metadata devices, hence the superblocks to
3030  * enforce recreation based on the passed in table parameters.
3031  *
3032  */
3033 static int raid_ctr(struct dm_target *ti, unsigned int argc, char **argv)
3034 {
3035 	int r;
3036 	bool resize = false;
3037 	struct raid_type *rt;
3038 	unsigned int num_raid_params, num_raid_devs;
3039 	sector_t calculated_dev_sectors, rdev_sectors, reshape_sectors;
3040 	struct raid_set *rs = NULL;
3041 	const char *arg;
3042 	struct rs_layout rs_layout;
3043 	struct dm_arg_set as = { argc, argv }, as_nrd;
3044 	struct dm_arg _args[] = {
3045 		{ 0, as.argc, "Cannot understand number of raid parameters" },
3046 		{ 1, 254, "Cannot understand number of raid devices parameters" }
3047 	};
3048 
3049 	/* Must have <raid_type> */
3050 	arg = dm_shift_arg(&as);
3051 	if (!arg) {
3052 		ti->error = "No arguments";
3053 		return -EINVAL;
3054 	}
3055 
3056 	rt = get_raid_type(arg);
3057 	if (!rt) {
3058 		ti->error = "Unrecognised raid_type";
3059 		return -EINVAL;
3060 	}
3061 
3062 	/* Must have <#raid_params> */
3063 	if (dm_read_arg_group(_args, &as, &num_raid_params, &ti->error))
3064 		return -EINVAL;
3065 
3066 	/* number of raid device tupples <meta_dev data_dev> */
3067 	as_nrd = as;
3068 	dm_consume_args(&as_nrd, num_raid_params);
3069 	_args[1].max = (as_nrd.argc - 1) / 2;
3070 	if (dm_read_arg(_args + 1, &as_nrd, &num_raid_devs, &ti->error))
3071 		return -EINVAL;
3072 
3073 	if (!__within_range(num_raid_devs, 1, MAX_RAID_DEVICES)) {
3074 		ti->error = "Invalid number of supplied raid devices";
3075 		return -EINVAL;
3076 	}
3077 
3078 	rs = raid_set_alloc(ti, rt, num_raid_devs);
3079 	if (IS_ERR(rs))
3080 		return PTR_ERR(rs);
3081 
3082 	r = parse_raid_params(rs, &as, num_raid_params);
3083 	if (r)
3084 		goto bad;
3085 
3086 	r = parse_dev_params(rs, &as);
3087 	if (r)
3088 		goto bad;
3089 
3090 	rs->md.sync_super = super_sync;
3091 
3092 	/*
3093 	 * Calculate ctr requested array and device sizes to allow
3094 	 * for superblock analysis needing device sizes defined.
3095 	 *
3096 	 * Any existing superblock will overwrite the array and device sizes
3097 	 */
3098 	r = rs_set_dev_and_array_sectors(rs, false);
3099 	if (r)
3100 		goto bad;
3101 
3102 	calculated_dev_sectors = rs->md.dev_sectors;
3103 
3104 	/*
3105 	 * Backup any new raid set level, layout, ...
3106 	 * requested to be able to compare to superblock
3107 	 * members for conversion decisions.
3108 	 */
3109 	rs_config_backup(rs, &rs_layout);
3110 
3111 	r = analyse_superblocks(ti, rs);
3112 	if (r)
3113 		goto bad;
3114 
3115 	rdev_sectors = __rdev_sectors(rs);
3116 	if (!rdev_sectors) {
3117 		ti->error = "Invalid rdev size";
3118 		r = -EINVAL;
3119 		goto bad;
3120 	}
3121 
3122 
3123 	reshape_sectors = _get_reshape_sectors(rs);
3124 	if (calculated_dev_sectors != rdev_sectors)
3125 		resize = calculated_dev_sectors != (reshape_sectors ? rdev_sectors - reshape_sectors : rdev_sectors);
3126 
3127 	INIT_WORK(&rs->md.event_work, do_table_event);
3128 	ti->private = rs;
3129 	ti->num_flush_bios = 1;
3130 
3131 	/* Restore any requested new layout for conversion decision */
3132 	rs_config_restore(rs, &rs_layout);
3133 
3134 	/*
3135 	 * Now that we have any superblock metadata available,
3136 	 * check for new, recovering, reshaping, to be taken over,
3137 	 * to be reshaped or an existing, unchanged raid set to
3138 	 * run in sequence.
3139 	 */
3140 	if (test_bit(MD_ARRAY_FIRST_USE, &rs->md.flags)) {
3141 		/* A new raid6 set has to be recovered to ensure proper parity and Q-Syndrome */
3142 		if (rs_is_raid6(rs) &&
3143 		    test_bit(__CTR_FLAG_NOSYNC, &rs->ctr_flags)) {
3144 			ti->error = "'nosync' not allowed for new raid6 set";
3145 			r = -EINVAL;
3146 			goto bad;
3147 		}
3148 		rs_setup_recovery(rs, 0);
3149 		set_bit(RT_FLAG_UPDATE_SBS, &rs->runtime_flags);
3150 		rs_set_new(rs);
3151 	} else if (rs_is_recovering(rs)) {
3152 		/* A recovering raid set may be resized */
3153 		; /* skip setup rs */
3154 	} else if (rs_is_reshaping(rs)) {
3155 		/* Have to reject size change request during reshape */
3156 		if (resize) {
3157 			ti->error = "Can't resize a reshaping raid set";
3158 			r = -EPERM;
3159 			goto bad;
3160 		}
3161 		/* skip setup rs */
3162 	} else if (rs_takeover_requested(rs)) {
3163 		if (rs_is_reshaping(rs)) {
3164 			ti->error = "Can't takeover a reshaping raid set";
3165 			r = -EPERM;
3166 			goto bad;
3167 		}
3168 
3169 		/* We can't takeover a journaled raid4/5/6 */
3170 		if (test_bit(__CTR_FLAG_JOURNAL_DEV, &rs->ctr_flags)) {
3171 			ti->error = "Can't takeover a journaled raid4/5/6 set";
3172 			r = -EPERM;
3173 			goto bad;
3174 		}
3175 
3176 		/*
3177 		 * If a takeover is needed, userspace sets any additional
3178 		 * devices to rebuild and we can check for a valid request here.
3179 		 *
3180 		 * If acceptible, set the level to the new requested
3181 		 * one, prohibit requesting recovery, allow the raid
3182 		 * set to run and store superblocks during resume.
3183 		 */
3184 		r = rs_check_takeover(rs);
3185 		if (r)
3186 			goto bad;
3187 
3188 		r = rs_setup_takeover(rs);
3189 		if (r)
3190 			goto bad;
3191 
3192 		set_bit(RT_FLAG_UPDATE_SBS, &rs->runtime_flags);
3193 		/* Takeover ain't recovery, so disable recovery */
3194 		rs_setup_recovery(rs, MaxSector);
3195 		rs_set_new(rs);
3196 	} else if (rs_reshape_requested(rs)) {
3197 		/*
3198 		 * No need to check for 'ongoing' takeover here, because takeover
3199 		 * is an instant operation as oposed to an ongoing reshape.
3200 		 */
3201 
3202 		/* We can't reshape a journaled raid4/5/6 */
3203 		if (test_bit(__CTR_FLAG_JOURNAL_DEV, &rs->ctr_flags)) {
3204 			ti->error = "Can't reshape a journaled raid4/5/6 set";
3205 			r = -EPERM;
3206 			goto bad;
3207 		}
3208 
3209 		/* Out-of-place space has to be available to allow for a reshape unless raid1! */
3210 		if (reshape_sectors || rs_is_raid1(rs)) {
3211 			/*
3212 			  * We can only prepare for a reshape here, because the
3213 			  * raid set needs to run to provide the repective reshape
3214 			  * check functions via its MD personality instance.
3215 			  *
3216 			  * So do the reshape check after md_run() succeeded.
3217 			  */
3218 			r = rs_prepare_reshape(rs);
3219 			if (r)
3220 				return r;
3221 
3222 			/* Reshaping ain't recovery, so disable recovery */
3223 			rs_setup_recovery(rs, MaxSector);
3224 		}
3225 		rs_set_cur(rs);
3226 	} else {
3227 		/* May not set recovery when a device rebuild is requested */
3228 		if (test_bit(__CTR_FLAG_REBUILD, &rs->ctr_flags)) {
3229 			rs_setup_recovery(rs, MaxSector);
3230 			set_bit(RT_FLAG_UPDATE_SBS, &rs->runtime_flags);
3231 		} else
3232 			rs_setup_recovery(rs, test_bit(__CTR_FLAG_SYNC, &rs->ctr_flags) ?
3233 					      0 : (resize ? calculated_dev_sectors : MaxSector));
3234 		rs_set_cur(rs);
3235 	}
3236 
3237 	/* If constructor requested it, change data and new_data offsets */
3238 	r = rs_adjust_data_offsets(rs);
3239 	if (r)
3240 		goto bad;
3241 
3242 	/* Start raid set read-only and assumed clean to change in raid_resume() */
3243 	rs->md.ro = 1;
3244 	rs->md.in_sync = 1;
3245 	set_bit(MD_RECOVERY_FROZEN, &rs->md.recovery);
3246 
3247 	/* Has to be held on running the array */
3248 	mddev_lock_nointr(&rs->md);
3249 	r = md_run(&rs->md);
3250 	rs->md.in_sync = 0; /* Assume already marked dirty */
3251 	if (r) {
3252 		ti->error = "Failed to run raid array";
3253 		mddev_unlock(&rs->md);
3254 		goto bad;
3255 	}
3256 
3257 	r = md_start(&rs->md);
3258 
3259 	if (r) {
3260 		ti->error = "Failed to start raid array";
3261 		mddev_unlock(&rs->md);
3262 		goto bad_md_start;
3263 	}
3264 
3265 	rs->callbacks.congested_fn = raid_is_congested;
3266 	dm_table_add_target_callbacks(ti->table, &rs->callbacks);
3267 
3268 	/* If raid4/5/6 journal mode explictely requested (only possible with journal dev) -> set it */
3269 	if (test_bit(__CTR_FLAG_JOURNAL_MODE, &rs->ctr_flags)) {
3270 		r = r5c_journal_mode_set(&rs->md, rs->journal_dev.mode);
3271 		if (r) {
3272 			ti->error = "Failed to set raid4/5/6 journal mode";
3273 			mddev_unlock(&rs->md);
3274 			goto bad_journal_mode_set;
3275 		}
3276 	}
3277 
3278 	mddev_suspend(&rs->md);
3279 	set_bit(RT_FLAG_RS_SUSPENDED, &rs->runtime_flags);
3280 
3281 	/* Try to adjust the raid4/5/6 stripe cache size to the stripe size */
3282 	if (rs_is_raid456(rs)) {
3283 		r = rs_set_raid456_stripe_cache(rs);
3284 		if (r)
3285 			goto bad_stripe_cache;
3286 	}
3287 
3288 	/* Now do an early reshape check */
3289 	if (test_bit(RT_FLAG_RESHAPE_RS, &rs->runtime_flags)) {
3290 		r = rs_check_reshape(rs);
3291 		if (r)
3292 			goto bad_check_reshape;
3293 
3294 		/* Restore new, ctr requested layout to perform check */
3295 		rs_config_restore(rs, &rs_layout);
3296 
3297 		if (rs->md.pers->start_reshape) {
3298 			r = rs->md.pers->check_reshape(&rs->md);
3299 			if (r) {
3300 				ti->error = "Reshape check failed";
3301 				goto bad_check_reshape;
3302 			}
3303 		}
3304 	}
3305 
3306 	/* Disable/enable discard support on raid set. */
3307 	configure_discard_support(rs);
3308 
3309 	mddev_unlock(&rs->md);
3310 	return 0;
3311 
3312 bad_md_start:
3313 bad_journal_mode_set:
3314 bad_stripe_cache:
3315 bad_check_reshape:
3316 	md_stop(&rs->md);
3317 bad:
3318 	raid_set_free(rs);
3319 
3320 	return r;
3321 }
3322 
3323 static void raid_dtr(struct dm_target *ti)
3324 {
3325 	struct raid_set *rs = ti->private;
3326 
3327 	list_del_init(&rs->callbacks.list);
3328 	md_stop(&rs->md);
3329 	raid_set_free(rs);
3330 }
3331 
3332 static int raid_map(struct dm_target *ti, struct bio *bio)
3333 {
3334 	struct raid_set *rs = ti->private;
3335 	struct mddev *mddev = &rs->md;
3336 
3337 	/*
3338 	 * If we're reshaping to add disk(s)), ti->len and
3339 	 * mddev->array_sectors will differ during the process
3340 	 * (ti->len > mddev->array_sectors), so we have to requeue
3341 	 * bios with addresses > mddev->array_sectors here or
3342 	 * there will occur accesses past EOD of the component
3343 	 * data images thus erroring the raid set.
3344 	 */
3345 	if (unlikely(bio_end_sector(bio) > mddev->array_sectors))
3346 		return DM_MAPIO_REQUEUE;
3347 
3348 	md_handle_request(mddev, bio);
3349 
3350 	return DM_MAPIO_SUBMITTED;
3351 }
3352 
3353 /* Return string describing the current sync action of @mddev */
3354 static const char *decipher_sync_action(struct mddev *mddev, unsigned long recovery)
3355 {
3356 	if (test_bit(MD_RECOVERY_FROZEN, &recovery))
3357 		return "frozen";
3358 
3359 	/* The MD sync thread can be done with io but still be running */
3360 	if (!test_bit(MD_RECOVERY_DONE, &recovery) &&
3361 	    (test_bit(MD_RECOVERY_RUNNING, &recovery) ||
3362 	     (!mddev->ro && test_bit(MD_RECOVERY_NEEDED, &recovery)))) {
3363 		if (test_bit(MD_RECOVERY_RESHAPE, &recovery))
3364 			return "reshape";
3365 
3366 		if (test_bit(MD_RECOVERY_SYNC, &recovery)) {
3367 			if (!test_bit(MD_RECOVERY_REQUESTED, &recovery))
3368 				return "resync";
3369 			else if (test_bit(MD_RECOVERY_CHECK, &recovery))
3370 				return "check";
3371 			return "repair";
3372 		}
3373 
3374 		if (test_bit(MD_RECOVERY_RECOVER, &recovery))
3375 			return "recover";
3376 	}
3377 
3378 	return "idle";
3379 }
3380 
3381 /*
3382  * Return status string for @rdev
3383  *
3384  * Status characters:
3385  *
3386  *  'D' = Dead/Failed raid set component or raid4/5/6 journal device
3387  *  'a' = Alive but not in-sync raid set component _or_ alive raid4/5/6 'write_back' journal device
3388  *  'A' = Alive and in-sync raid set component _or_ alive raid4/5/6 'write_through' journal device
3389  *  '-' = Non-existing device (i.e. uspace passed '- -' into the ctr)
3390  */
3391 static const char *__raid_dev_status(struct raid_set *rs, struct md_rdev *rdev)
3392 {
3393 	if (!rdev->bdev)
3394 		return "-";
3395 	else if (test_bit(Faulty, &rdev->flags))
3396 		return "D";
3397 	else if (test_bit(Journal, &rdev->flags))
3398 		return (rs->journal_dev.mode == R5C_JOURNAL_MODE_WRITE_THROUGH) ? "A" : "a";
3399 	else if (test_bit(RT_FLAG_RS_RESYNCING, &rs->runtime_flags) ||
3400 		 (!test_bit(RT_FLAG_RS_IN_SYNC, &rs->runtime_flags) &&
3401 		  !test_bit(In_sync, &rdev->flags)))
3402 		return "a";
3403 	else
3404 		return "A";
3405 }
3406 
3407 /* Helper to return resync/reshape progress for @rs and runtime flags for raid set in sync / resynching */
3408 static sector_t rs_get_progress(struct raid_set *rs, unsigned long recovery,
3409 				sector_t resync_max_sectors)
3410 {
3411 	sector_t r;
3412 	struct mddev *mddev = &rs->md;
3413 
3414 	clear_bit(RT_FLAG_RS_IN_SYNC, &rs->runtime_flags);
3415 	clear_bit(RT_FLAG_RS_RESYNCING, &rs->runtime_flags);
3416 
3417 	if (rs_is_raid0(rs)) {
3418 		r = resync_max_sectors;
3419 		set_bit(RT_FLAG_RS_IN_SYNC, &rs->runtime_flags);
3420 
3421 	} else {
3422 		if (!test_bit(__CTR_FLAG_NOSYNC, &rs->ctr_flags) &&
3423 		    !test_bit(MD_RECOVERY_INTR, &recovery) &&
3424 		    (test_bit(MD_RECOVERY_NEEDED, &recovery) ||
3425 		     test_bit(MD_RECOVERY_RESHAPE, &recovery) ||
3426 		     test_bit(MD_RECOVERY_RUNNING, &recovery)))
3427 			r = mddev->curr_resync_completed;
3428 		else
3429 			r = mddev->recovery_cp;
3430 
3431 		if (r >= resync_max_sectors &&
3432 		    (!test_bit(MD_RECOVERY_REQUESTED, &recovery) ||
3433 		     (!test_bit(MD_RECOVERY_FROZEN, &recovery) &&
3434 		      !test_bit(MD_RECOVERY_NEEDED, &recovery) &&
3435 		      !test_bit(MD_RECOVERY_RUNNING, &recovery)))) {
3436 			/*
3437 			 * Sync complete.
3438 			 */
3439 			/* In case we have finished recovering, the array is in sync. */
3440 			if (test_bit(MD_RECOVERY_RECOVER, &recovery))
3441 				set_bit(RT_FLAG_RS_IN_SYNC, &rs->runtime_flags);
3442 
3443 		} else if (test_bit(MD_RECOVERY_RECOVER, &recovery)) {
3444 			/*
3445 			 * In case we are recovering, the array is not in sync
3446 			 * and health chars should show the recovering legs.
3447 			 */
3448 			;
3449 
3450 		} else if (test_bit(MD_RECOVERY_SYNC, &recovery) &&
3451 			   !test_bit(MD_RECOVERY_REQUESTED, &recovery)) {
3452 			/*
3453 			 * If "resync" is occurring, the raid set
3454 			 * is or may be out of sync hence the health
3455 			 * characters shall be 'a'.
3456 			 */
3457 			set_bit(RT_FLAG_RS_RESYNCING, &rs->runtime_flags);
3458 
3459 		} else if (test_bit(MD_RECOVERY_RESHAPE, &recovery) &&
3460 			   !test_bit(MD_RECOVERY_REQUESTED, &recovery)) {
3461 			/*
3462 			 * If "reshape" is occurring, the raid set
3463 			 * is or may be out of sync hence the health
3464 			 * characters shall be 'a'.
3465 			 */
3466 			set_bit(RT_FLAG_RS_RESYNCING, &rs->runtime_flags);
3467 
3468 		} else if (test_bit(MD_RECOVERY_REQUESTED, &recovery)) {
3469 			/*
3470 			 * If "check" or "repair" is occurring, the raid set has
3471 			 * undergone an initial sync and the health characters
3472 			 * should not be 'a' anymore.
3473 			 */
3474 			set_bit(RT_FLAG_RS_IN_SYNC, &rs->runtime_flags);
3475 
3476 		} else {
3477 			struct md_rdev *rdev;
3478 
3479 			/*
3480 			 * We are idle and recovery is needed, prevent 'A' chars race
3481 			 * caused by components still set to in-sync by constrcuctor.
3482 			 */
3483 			if (test_bit(MD_RECOVERY_NEEDED, &recovery))
3484 				set_bit(RT_FLAG_RS_RESYNCING, &rs->runtime_flags);
3485 
3486 			/*
3487 			 * The raid set may be doing an initial sync, or it may
3488 			 * be rebuilding individual components.	 If all the
3489 			 * devices are In_sync, then it is the raid set that is
3490 			 * being initialized.
3491 			 */
3492 			set_bit(RT_FLAG_RS_IN_SYNC, &rs->runtime_flags);
3493 			rdev_for_each(rdev, mddev)
3494 				if (!test_bit(Journal, &rdev->flags) &&
3495 				    !test_bit(In_sync, &rdev->flags)) {
3496 					clear_bit(RT_FLAG_RS_IN_SYNC, &rs->runtime_flags);
3497 					break;
3498 				}
3499 		}
3500 	}
3501 
3502 	return min(r, resync_max_sectors);
3503 }
3504 
3505 /* Helper to return @dev name or "-" if !@dev */
3506 static const char *__get_dev_name(struct dm_dev *dev)
3507 {
3508 	return dev ? dev->name : "-";
3509 }
3510 
3511 static void raid_status(struct dm_target *ti, status_type_t type,
3512 			unsigned int status_flags, char *result, unsigned int maxlen)
3513 {
3514 	struct raid_set *rs = ti->private;
3515 	struct mddev *mddev = &rs->md;
3516 	struct r5conf *conf = mddev->private;
3517 	int i, max_nr_stripes = conf ? conf->max_nr_stripes : 0;
3518 	unsigned long recovery;
3519 	unsigned int raid_param_cnt = 1; /* at least 1 for chunksize */
3520 	unsigned int sz = 0;
3521 	unsigned int rebuild_disks;
3522 	unsigned int write_mostly_params = 0;
3523 	sector_t progress, resync_max_sectors, resync_mismatches;
3524 	const char *sync_action;
3525 	struct raid_type *rt;
3526 
3527 	switch (type) {
3528 	case STATUSTYPE_INFO:
3529 		/* *Should* always succeed */
3530 		rt = get_raid_type_by_ll(mddev->new_level, mddev->new_layout);
3531 		if (!rt)
3532 			return;
3533 
3534 		DMEMIT("%s %d ", rt->name, mddev->raid_disks);
3535 
3536 		/* Access most recent mddev properties for status output */
3537 		smp_rmb();
3538 		recovery = rs->md.recovery;
3539 		/* Get sensible max sectors even if raid set not yet started */
3540 		resync_max_sectors = test_bit(RT_FLAG_RS_PRERESUMED, &rs->runtime_flags) ?
3541 				      mddev->resync_max_sectors : mddev->dev_sectors;
3542 		progress = rs_get_progress(rs, recovery, resync_max_sectors);
3543 		resync_mismatches = (mddev->last_sync_action && !strcasecmp(mddev->last_sync_action, "check")) ?
3544 				    atomic64_read(&mddev->resync_mismatches) : 0;
3545 		sync_action = decipher_sync_action(&rs->md, recovery);
3546 
3547 		/* HM FIXME: do we want another state char for raid0? It shows 'D'/'A'/'-' now */
3548 		for (i = 0; i < rs->raid_disks; i++)
3549 			DMEMIT(__raid_dev_status(rs, &rs->dev[i].rdev));
3550 
3551 		/*
3552 		 * In-sync/Reshape ratio:
3553 		 *  The in-sync ratio shows the progress of:
3554 		 *   - Initializing the raid set
3555 		 *   - Rebuilding a subset of devices of the raid set
3556 		 *  The user can distinguish between the two by referring
3557 		 *  to the status characters.
3558 		 *
3559 		 *  The reshape ratio shows the progress of
3560 		 *  changing the raid layout or the number of
3561 		 *  disks of a raid set
3562 		 */
3563 		DMEMIT(" %llu/%llu", (unsigned long long) progress,
3564 				     (unsigned long long) resync_max_sectors);
3565 
3566 		/*
3567 		 * v1.5.0+:
3568 		 *
3569 		 * Sync action:
3570 		 *   See Documentation/device-mapper/dm-raid.txt for
3571 		 *   information on each of these states.
3572 		 */
3573 		DMEMIT(" %s", sync_action);
3574 
3575 		/*
3576 		 * v1.5.0+:
3577 		 *
3578 		 * resync_mismatches/mismatch_cnt
3579 		 *   This field shows the number of discrepancies found when
3580 		 *   performing a "check" of the raid set.
3581 		 */
3582 		DMEMIT(" %llu", (unsigned long long) resync_mismatches);
3583 
3584 		/*
3585 		 * v1.9.0+:
3586 		 *
3587 		 * data_offset (needed for out of space reshaping)
3588 		 *   This field shows the data offset into the data
3589 		 *   image LV where the first stripes data starts.
3590 		 *
3591 		 * We keep data_offset equal on all raid disks of the set,
3592 		 * so retrieving it from the first raid disk is sufficient.
3593 		 */
3594 		DMEMIT(" %llu", (unsigned long long) rs->dev[0].rdev.data_offset);
3595 
3596 		/*
3597 		 * v1.10.0+:
3598 		 */
3599 		DMEMIT(" %s", test_bit(__CTR_FLAG_JOURNAL_DEV, &rs->ctr_flags) ?
3600 			      __raid_dev_status(rs, &rs->journal_dev.rdev) : "-");
3601 		break;
3602 
3603 	case STATUSTYPE_TABLE:
3604 		/* Report the table line string you would use to construct this raid set */
3605 
3606 		/* Calculate raid parameter count */
3607 		for (i = 0; i < rs->raid_disks; i++)
3608 			if (test_bit(WriteMostly, &rs->dev[i].rdev.flags))
3609 				write_mostly_params += 2;
3610 		rebuild_disks = memweight(rs->rebuild_disks, DISKS_ARRAY_ELEMS * sizeof(*rs->rebuild_disks));
3611 		raid_param_cnt += rebuild_disks * 2 +
3612 				  write_mostly_params +
3613 				  hweight32(rs->ctr_flags & CTR_FLAG_OPTIONS_NO_ARGS) +
3614 				  hweight32(rs->ctr_flags & CTR_FLAG_OPTIONS_ONE_ARG) * 2 +
3615 				  (test_bit(__CTR_FLAG_JOURNAL_DEV, &rs->ctr_flags) ? 2 : 0) +
3616 				  (test_bit(__CTR_FLAG_JOURNAL_MODE, &rs->ctr_flags) ? 2 : 0);
3617 
3618 		/* Emit table line */
3619 		/* This has to be in the documented order for userspace! */
3620 		DMEMIT("%s %u %u", rs->raid_type->name, raid_param_cnt, mddev->new_chunk_sectors);
3621 		if (test_bit(__CTR_FLAG_SYNC, &rs->ctr_flags))
3622 			DMEMIT(" %s", dm_raid_arg_name_by_flag(CTR_FLAG_SYNC));
3623 		if (test_bit(__CTR_FLAG_NOSYNC, &rs->ctr_flags))
3624 			DMEMIT(" %s", dm_raid_arg_name_by_flag(CTR_FLAG_NOSYNC));
3625 		if (rebuild_disks)
3626 			for (i = 0; i < rs->raid_disks; i++)
3627 				if (test_bit(rs->dev[i].rdev.raid_disk, (void *) rs->rebuild_disks))
3628 					DMEMIT(" %s %u", dm_raid_arg_name_by_flag(CTR_FLAG_REBUILD),
3629 							 rs->dev[i].rdev.raid_disk);
3630 		if (test_bit(__CTR_FLAG_DAEMON_SLEEP, &rs->ctr_flags))
3631 			DMEMIT(" %s %lu", dm_raid_arg_name_by_flag(CTR_FLAG_DAEMON_SLEEP),
3632 					  mddev->bitmap_info.daemon_sleep);
3633 		if (test_bit(__CTR_FLAG_MIN_RECOVERY_RATE, &rs->ctr_flags))
3634 			DMEMIT(" %s %d", dm_raid_arg_name_by_flag(CTR_FLAG_MIN_RECOVERY_RATE),
3635 					 mddev->sync_speed_min);
3636 		if (test_bit(__CTR_FLAG_MAX_RECOVERY_RATE, &rs->ctr_flags))
3637 			DMEMIT(" %s %d", dm_raid_arg_name_by_flag(CTR_FLAG_MAX_RECOVERY_RATE),
3638 					 mddev->sync_speed_max);
3639 		if (write_mostly_params)
3640 			for (i = 0; i < rs->raid_disks; i++)
3641 				if (test_bit(WriteMostly, &rs->dev[i].rdev.flags))
3642 					DMEMIT(" %s %d", dm_raid_arg_name_by_flag(CTR_FLAG_WRITE_MOSTLY),
3643 					       rs->dev[i].rdev.raid_disk);
3644 		if (test_bit(__CTR_FLAG_MAX_WRITE_BEHIND, &rs->ctr_flags))
3645 			DMEMIT(" %s %lu", dm_raid_arg_name_by_flag(CTR_FLAG_MAX_WRITE_BEHIND),
3646 					  mddev->bitmap_info.max_write_behind);
3647 		if (test_bit(__CTR_FLAG_STRIPE_CACHE, &rs->ctr_flags))
3648 			DMEMIT(" %s %d", dm_raid_arg_name_by_flag(CTR_FLAG_STRIPE_CACHE),
3649 					 max_nr_stripes);
3650 		if (test_bit(__CTR_FLAG_REGION_SIZE, &rs->ctr_flags))
3651 			DMEMIT(" %s %llu", dm_raid_arg_name_by_flag(CTR_FLAG_REGION_SIZE),
3652 					   (unsigned long long) to_sector(mddev->bitmap_info.chunksize));
3653 		if (test_bit(__CTR_FLAG_RAID10_COPIES, &rs->ctr_flags))
3654 			DMEMIT(" %s %d", dm_raid_arg_name_by_flag(CTR_FLAG_RAID10_COPIES),
3655 					 raid10_md_layout_to_copies(mddev->layout));
3656 		if (test_bit(__CTR_FLAG_RAID10_FORMAT, &rs->ctr_flags))
3657 			DMEMIT(" %s %s", dm_raid_arg_name_by_flag(CTR_FLAG_RAID10_FORMAT),
3658 					 raid10_md_layout_to_format(mddev->layout));
3659 		if (test_bit(__CTR_FLAG_DELTA_DISKS, &rs->ctr_flags))
3660 			DMEMIT(" %s %d", dm_raid_arg_name_by_flag(CTR_FLAG_DELTA_DISKS),
3661 					 max(rs->delta_disks, mddev->delta_disks));
3662 		if (test_bit(__CTR_FLAG_DATA_OFFSET, &rs->ctr_flags))
3663 			DMEMIT(" %s %llu", dm_raid_arg_name_by_flag(CTR_FLAG_DATA_OFFSET),
3664 					   (unsigned long long) rs->data_offset);
3665 		if (test_bit(__CTR_FLAG_JOURNAL_DEV, &rs->ctr_flags))
3666 			DMEMIT(" %s %s", dm_raid_arg_name_by_flag(CTR_FLAG_JOURNAL_DEV),
3667 					__get_dev_name(rs->journal_dev.dev));
3668 		if (test_bit(__CTR_FLAG_JOURNAL_MODE, &rs->ctr_flags))
3669 			DMEMIT(" %s %s", dm_raid_arg_name_by_flag(CTR_FLAG_JOURNAL_MODE),
3670 					 md_journal_mode_to_dm_raid(rs->journal_dev.mode));
3671 		DMEMIT(" %d", rs->raid_disks);
3672 		for (i = 0; i < rs->raid_disks; i++)
3673 			DMEMIT(" %s %s", __get_dev_name(rs->dev[i].meta_dev),
3674 					 __get_dev_name(rs->dev[i].data_dev));
3675 	}
3676 }
3677 
3678 static int raid_message(struct dm_target *ti, unsigned int argc, char **argv,
3679 			char *result, unsigned maxlen)
3680 {
3681 	struct raid_set *rs = ti->private;
3682 	struct mddev *mddev = &rs->md;
3683 
3684 	if (!mddev->pers || !mddev->pers->sync_request)
3685 		return -EINVAL;
3686 
3687 	if (!strcasecmp(argv[0], "frozen"))
3688 		set_bit(MD_RECOVERY_FROZEN, &mddev->recovery);
3689 	else
3690 		clear_bit(MD_RECOVERY_FROZEN, &mddev->recovery);
3691 
3692 	if (!strcasecmp(argv[0], "idle") || !strcasecmp(argv[0], "frozen")) {
3693 		if (mddev->sync_thread) {
3694 			set_bit(MD_RECOVERY_INTR, &mddev->recovery);
3695 			md_reap_sync_thread(mddev);
3696 		}
3697 	} else if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery) ||
3698 		   test_bit(MD_RECOVERY_NEEDED, &mddev->recovery))
3699 		return -EBUSY;
3700 	else if (!strcasecmp(argv[0], "resync"))
3701 		; /* MD_RECOVERY_NEEDED set below */
3702 	else if (!strcasecmp(argv[0], "recover"))
3703 		set_bit(MD_RECOVERY_RECOVER, &mddev->recovery);
3704 	else {
3705 		if (!strcasecmp(argv[0], "check")) {
3706 			set_bit(MD_RECOVERY_CHECK, &mddev->recovery);
3707 			set_bit(MD_RECOVERY_REQUESTED, &mddev->recovery);
3708 			set_bit(MD_RECOVERY_SYNC, &mddev->recovery);
3709 		} else if (!strcasecmp(argv[0], "repair")) {
3710 			set_bit(MD_RECOVERY_REQUESTED, &mddev->recovery);
3711 			set_bit(MD_RECOVERY_SYNC, &mddev->recovery);
3712 		} else
3713 			return -EINVAL;
3714 	}
3715 	if (mddev->ro == 2) {
3716 		/* A write to sync_action is enough to justify
3717 		 * canceling read-auto mode
3718 		 */
3719 		mddev->ro = 0;
3720 		if (!mddev->suspended && mddev->sync_thread)
3721 			md_wakeup_thread(mddev->sync_thread);
3722 	}
3723 	set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
3724 	if (!mddev->suspended && mddev->thread)
3725 		md_wakeup_thread(mddev->thread);
3726 
3727 	return 0;
3728 }
3729 
3730 static int raid_iterate_devices(struct dm_target *ti,
3731 				iterate_devices_callout_fn fn, void *data)
3732 {
3733 	struct raid_set *rs = ti->private;
3734 	unsigned int i;
3735 	int r = 0;
3736 
3737 	for (i = 0; !r && i < rs->md.raid_disks; i++)
3738 		if (rs->dev[i].data_dev)
3739 			r = fn(ti,
3740 				 rs->dev[i].data_dev,
3741 				 0, /* No offset on data devs */
3742 				 rs->md.dev_sectors,
3743 				 data);
3744 
3745 	return r;
3746 }
3747 
3748 static void raid_io_hints(struct dm_target *ti, struct queue_limits *limits)
3749 {
3750 	struct raid_set *rs = ti->private;
3751 	unsigned int chunk_size = to_bytes(rs->md.chunk_sectors);
3752 
3753 	blk_limits_io_min(limits, chunk_size);
3754 	blk_limits_io_opt(limits, chunk_size * mddev_data_stripes(rs));
3755 }
3756 
3757 static void raid_postsuspend(struct dm_target *ti)
3758 {
3759 	struct raid_set *rs = ti->private;
3760 
3761 	if (!test_and_set_bit(RT_FLAG_RS_SUSPENDED, &rs->runtime_flags)) {
3762 		/* Writes have to be stopped before suspending to avoid deadlocks. */
3763 		if (!test_bit(MD_RECOVERY_FROZEN, &rs->md.recovery))
3764 			md_stop_writes(&rs->md);
3765 
3766 		mddev_lock_nointr(&rs->md);
3767 		mddev_suspend(&rs->md);
3768 		mddev_unlock(&rs->md);
3769 	}
3770 }
3771 
3772 static void attempt_restore_of_faulty_devices(struct raid_set *rs)
3773 {
3774 	int i;
3775 	uint64_t cleared_failed_devices[DISKS_ARRAY_ELEMS];
3776 	unsigned long flags;
3777 	bool cleared = false;
3778 	struct dm_raid_superblock *sb;
3779 	struct mddev *mddev = &rs->md;
3780 	struct md_rdev *r;
3781 
3782 	/* RAID personalities have to provide hot add/remove methods or we need to bail out. */
3783 	if (!mddev->pers || !mddev->pers->hot_add_disk || !mddev->pers->hot_remove_disk)
3784 		return;
3785 
3786 	memset(cleared_failed_devices, 0, sizeof(cleared_failed_devices));
3787 
3788 	for (i = 0; i < mddev->raid_disks; i++) {
3789 		r = &rs->dev[i].rdev;
3790 		/* HM FIXME: enhance journal device recovery processing */
3791 		if (test_bit(Journal, &r->flags))
3792 			continue;
3793 
3794 		if (test_bit(Faulty, &r->flags) &&
3795 		    r->meta_bdev && !read_disk_sb(r, r->sb_size, true)) {
3796 			DMINFO("Faulty %s device #%d has readable super block."
3797 			       "  Attempting to revive it.",
3798 			       rs->raid_type->name, i);
3799 
3800 			/*
3801 			 * Faulty bit may be set, but sometimes the array can
3802 			 * be suspended before the personalities can respond
3803 			 * by removing the device from the array (i.e. calling
3804 			 * 'hot_remove_disk').	If they haven't yet removed
3805 			 * the failed device, its 'raid_disk' number will be
3806 			 * '>= 0' - meaning we must call this function
3807 			 * ourselves.
3808 			 */
3809 			flags = r->flags;
3810 			clear_bit(In_sync, &r->flags); /* Mandatory for hot remove. */
3811 			if (r->raid_disk >= 0) {
3812 				if (mddev->pers->hot_remove_disk(mddev, r)) {
3813 					/* Failed to revive this device, try next */
3814 					r->flags = flags;
3815 					continue;
3816 				}
3817 			} else
3818 				r->raid_disk = r->saved_raid_disk = i;
3819 
3820 			clear_bit(Faulty, &r->flags);
3821 			clear_bit(WriteErrorSeen, &r->flags);
3822 
3823 			if (mddev->pers->hot_add_disk(mddev, r)) {
3824 				/* Failed to revive this device, try next */
3825 				r->raid_disk = r->saved_raid_disk = -1;
3826 				r->flags = flags;
3827 			} else {
3828 				clear_bit(In_sync, &r->flags);
3829 				r->recovery_offset = 0;
3830 				set_bit(i, (void *) cleared_failed_devices);
3831 				cleared = true;
3832 			}
3833 		}
3834 	}
3835 
3836 	/* If any failed devices could be cleared, update all sbs failed_devices bits */
3837 	if (cleared) {
3838 		uint64_t failed_devices[DISKS_ARRAY_ELEMS];
3839 
3840 		rdev_for_each(r, &rs->md) {
3841 			if (test_bit(Journal, &r->flags))
3842 				continue;
3843 
3844 			sb = page_address(r->sb_page);
3845 			sb_retrieve_failed_devices(sb, failed_devices);
3846 
3847 			for (i = 0; i < DISKS_ARRAY_ELEMS; i++)
3848 				failed_devices[i] &= ~cleared_failed_devices[i];
3849 
3850 			sb_update_failed_devices(sb, failed_devices);
3851 		}
3852 	}
3853 }
3854 
3855 static int __load_dirty_region_bitmap(struct raid_set *rs)
3856 {
3857 	int r = 0;
3858 
3859 	/* Try loading the bitmap unless "raid0", which does not have one */
3860 	if (!rs_is_raid0(rs) &&
3861 	    !test_and_set_bit(RT_FLAG_RS_BITMAP_LOADED, &rs->runtime_flags)) {
3862 		r = md_bitmap_load(&rs->md);
3863 		if (r)
3864 			DMERR("Failed to load bitmap");
3865 	}
3866 
3867 	return r;
3868 }
3869 
3870 /* Enforce updating all superblocks */
3871 static void rs_update_sbs(struct raid_set *rs)
3872 {
3873 	struct mddev *mddev = &rs->md;
3874 	int ro = mddev->ro;
3875 
3876 	set_bit(MD_SB_CHANGE_DEVS, &mddev->sb_flags);
3877 	mddev->ro = 0;
3878 	md_update_sb(mddev, 1);
3879 	mddev->ro = ro;
3880 }
3881 
3882 /*
3883  * Reshape changes raid algorithm of @rs to new one within personality
3884  * (e.g. raid6_zr -> raid6_nc), changes stripe size, adds/removes
3885  * disks from a raid set thus growing/shrinking it or resizes the set
3886  *
3887  * Call mddev_lock_nointr() before!
3888  */
3889 static int rs_start_reshape(struct raid_set *rs)
3890 {
3891 	int r;
3892 	struct mddev *mddev = &rs->md;
3893 	struct md_personality *pers = mddev->pers;
3894 
3895 	r = rs_setup_reshape(rs);
3896 	if (r)
3897 		return r;
3898 
3899 	/* Need to be resumed to be able to start reshape, recovery is frozen until raid_resume() though */
3900 	if (test_and_clear_bit(RT_FLAG_RS_SUSPENDED, &rs->runtime_flags))
3901 		mddev_resume(mddev);
3902 
3903 	/*
3904 	 * Check any reshape constraints enforced by the personalility
3905 	 *
3906 	 * May as well already kick the reshape off so that * pers->start_reshape() becomes optional.
3907 	 */
3908 	r = pers->check_reshape(mddev);
3909 	if (r) {
3910 		rs->ti->error = "pers->check_reshape() failed";
3911 		return r;
3912 	}
3913 
3914 	/*
3915 	 * Personality may not provide start reshape method in which
3916 	 * case check_reshape above has already covered everything
3917 	 */
3918 	if (pers->start_reshape) {
3919 		r = pers->start_reshape(mddev);
3920 		if (r) {
3921 			rs->ti->error = "pers->start_reshape() failed";
3922 			return r;
3923 		}
3924 	}
3925 
3926 	/* Suspend because a resume will happen in raid_resume() */
3927 	set_bit(RT_FLAG_RS_SUSPENDED, &rs->runtime_flags);
3928 	mddev_suspend(mddev);
3929 
3930 	/*
3931 	 * Now reshape got set up, update superblocks to
3932 	 * reflect the fact so that a table reload will
3933 	 * access proper superblock content in the ctr.
3934 	 */
3935 	rs_update_sbs(rs);
3936 
3937 	return 0;
3938 }
3939 
3940 static int raid_preresume(struct dm_target *ti)
3941 {
3942 	int r;
3943 	struct raid_set *rs = ti->private;
3944 	struct mddev *mddev = &rs->md;
3945 
3946 	/* This is a resume after a suspend of the set -> it's already started. */
3947 	if (test_and_set_bit(RT_FLAG_RS_PRERESUMED, &rs->runtime_flags))
3948 		return 0;
3949 
3950 	if (!test_bit(__CTR_FLAG_REBUILD, &rs->ctr_flags)) {
3951 		struct raid_set *rs_active = rs_find_active(rs);
3952 
3953 		if (rs_active) {
3954 			/*
3955 			 * In case no rebuilds have been requested
3956 			 * and an active table slot exists, copy
3957 			 * current resynchonization completed and
3958 			 * reshape position pointers across from
3959 			 * suspended raid set in the active slot.
3960 			 *
3961 			 * This resumes the new mapping at current
3962 			 * offsets to continue recover/reshape without
3963 			 * necessarily redoing a raid set partially or
3964 			 * causing data corruption in case of a reshape.
3965 			 */
3966 			if (rs_active->md.curr_resync_completed != MaxSector)
3967 				mddev->curr_resync_completed = rs_active->md.curr_resync_completed;
3968 			if (rs_active->md.reshape_position != MaxSector)
3969 				mddev->reshape_position = rs_active->md.reshape_position;
3970 		}
3971 	}
3972 
3973 	/*
3974 	 * The superblocks need to be updated on disk if the
3975 	 * array is new or new devices got added (thus zeroed
3976 	 * out by userspace) or __load_dirty_region_bitmap
3977 	 * will overwrite them in core with old data or fail.
3978 	 */
3979 	if (test_bit(RT_FLAG_UPDATE_SBS, &rs->runtime_flags))
3980 		rs_update_sbs(rs);
3981 
3982 	/* Load the bitmap from disk unless raid0 */
3983 	r = __load_dirty_region_bitmap(rs);
3984 	if (r)
3985 		return r;
3986 
3987 	/* Resize bitmap to adjust to changed region size (aka MD bitmap chunksize) */
3988 	if (test_bit(RT_FLAG_RS_BITMAP_LOADED, &rs->runtime_flags) && mddev->bitmap &&
3989 	    mddev->bitmap_info.chunksize != to_bytes(rs->requested_bitmap_chunk_sectors)) {
3990 		r = md_bitmap_resize(mddev->bitmap, mddev->dev_sectors,
3991 				     to_bytes(rs->requested_bitmap_chunk_sectors), 0);
3992 		if (r)
3993 			DMERR("Failed to resize bitmap");
3994 	}
3995 
3996 	/* Check for any resize/reshape on @rs and adjust/initiate */
3997 	/* Be prepared for mddev_resume() in raid_resume() */
3998 	set_bit(MD_RECOVERY_FROZEN, &mddev->recovery);
3999 	if (mddev->recovery_cp && mddev->recovery_cp < MaxSector) {
4000 		set_bit(MD_RECOVERY_SYNC, &mddev->recovery);
4001 		mddev->resync_min = mddev->recovery_cp;
4002 	}
4003 
4004 	/* Check for any reshape request unless new raid set */
4005 	if (test_bit(RT_FLAG_RESHAPE_RS, &rs->runtime_flags)) {
4006 		/* Initiate a reshape. */
4007 		rs_set_rdev_sectors(rs);
4008 		mddev_lock_nointr(mddev);
4009 		r = rs_start_reshape(rs);
4010 		mddev_unlock(mddev);
4011 		if (r)
4012 			DMWARN("Failed to check/start reshape, continuing without change");
4013 		r = 0;
4014 	}
4015 
4016 	return r;
4017 }
4018 
4019 static void raid_resume(struct dm_target *ti)
4020 {
4021 	struct raid_set *rs = ti->private;
4022 	struct mddev *mddev = &rs->md;
4023 
4024 	if (test_and_set_bit(RT_FLAG_RS_RESUMED, &rs->runtime_flags)) {
4025 		/*
4026 		 * A secondary resume while the device is active.
4027 		 * Take this opportunity to check whether any failed
4028 		 * devices are reachable again.
4029 		 */
4030 		attempt_restore_of_faulty_devices(rs);
4031 	}
4032 
4033 	if (test_and_clear_bit(RT_FLAG_RS_SUSPENDED, &rs->runtime_flags)) {
4034 		/* Only reduce raid set size before running a disk removing reshape. */
4035 		if (mddev->delta_disks < 0)
4036 			rs_set_capacity(rs);
4037 
4038 		mddev_lock_nointr(mddev);
4039 		clear_bit(MD_RECOVERY_FROZEN, &mddev->recovery);
4040 		mddev->ro = 0;
4041 		mddev->in_sync = 0;
4042 		mddev_resume(mddev);
4043 		mddev_unlock(mddev);
4044 	}
4045 }
4046 
4047 static struct target_type raid_target = {
4048 	.name = "raid",
4049 	.version = {1, 13, 2},
4050 	.module = THIS_MODULE,
4051 	.ctr = raid_ctr,
4052 	.dtr = raid_dtr,
4053 	.map = raid_map,
4054 	.status = raid_status,
4055 	.message = raid_message,
4056 	.iterate_devices = raid_iterate_devices,
4057 	.io_hints = raid_io_hints,
4058 	.postsuspend = raid_postsuspend,
4059 	.preresume = raid_preresume,
4060 	.resume = raid_resume,
4061 };
4062 
4063 static int __init dm_raid_init(void)
4064 {
4065 	DMINFO("Loading target version %u.%u.%u",
4066 	       raid_target.version[0],
4067 	       raid_target.version[1],
4068 	       raid_target.version[2]);
4069 	return dm_register_target(&raid_target);
4070 }
4071 
4072 static void __exit dm_raid_exit(void)
4073 {
4074 	dm_unregister_target(&raid_target);
4075 }
4076 
4077 module_init(dm_raid_init);
4078 module_exit(dm_raid_exit);
4079 
4080 module_param(devices_handle_discard_safely, bool, 0644);
4081 MODULE_PARM_DESC(devices_handle_discard_safely,
4082 		 "Set to Y if all devices in each array reliably return zeroes on reads from discarded regions");
4083 
4084 MODULE_DESCRIPTION(DM_NAME " raid0/1/10/4/5/6 target");
4085 MODULE_ALIAS("dm-raid0");
4086 MODULE_ALIAS("dm-raid1");
4087 MODULE_ALIAS("dm-raid10");
4088 MODULE_ALIAS("dm-raid4");
4089 MODULE_ALIAS("dm-raid5");
4090 MODULE_ALIAS("dm-raid6");
4091 MODULE_AUTHOR("Neil Brown <dm-devel@redhat.com>");
4092 MODULE_AUTHOR("Heinz Mauelshagen <dm-devel@redhat.com>");
4093 MODULE_LICENSE("GPL");
4094