xref: /linux/drivers/md/dm-raid.c (revision 81fa7a69c2174ed8de314b9c231ef30a8718e5e1)
1 /*
2  * Copyright (C) 2010-2011 Neil Brown
3  * Copyright (C) 2010-2018 Red Hat, Inc. All rights reserved.
4  *
5  * This file is released under the GPL.
6  */
7 
8 #include <linux/slab.h>
9 #include <linux/module.h>
10 
11 #include "md.h"
12 #include "raid1.h"
13 #include "raid5.h"
14 #include "raid10.h"
15 #include "md-bitmap.h"
16 
17 #include <linux/device-mapper.h>
18 
19 #define DM_MSG_PREFIX "raid"
20 #define	MAX_RAID_DEVICES	253 /* md-raid kernel limit */
21 
22 /*
23  * Minimum sectors of free reshape space per raid device
24  */
25 #define	MIN_FREE_RESHAPE_SPACE to_sector(4*4096)
26 
27 /*
28  * Minimum journal space 4 MiB in sectors.
29  */
30 #define	MIN_RAID456_JOURNAL_SPACE (4*2048)
31 
32 static bool devices_handle_discard_safely = false;
33 
34 /*
35  * The following flags are used by dm-raid.c to set up the array state.
36  * They must be cleared before md_run is called.
37  */
38 #define FirstUse 10		/* rdev flag */
39 
40 struct raid_dev {
41 	/*
42 	 * Two DM devices, one to hold metadata and one to hold the
43 	 * actual data/parity.	The reason for this is to not confuse
44 	 * ti->len and give more flexibility in altering size and
45 	 * characteristics.
46 	 *
47 	 * While it is possible for this device to be associated
48 	 * with a different physical device than the data_dev, it
49 	 * is intended for it to be the same.
50 	 *    |--------- Physical Device ---------|
51 	 *    |- meta_dev -|------ data_dev ------|
52 	 */
53 	struct dm_dev *meta_dev;
54 	struct dm_dev *data_dev;
55 	struct md_rdev rdev;
56 };
57 
58 /*
59  * Bits for establishing rs->ctr_flags
60  *
61  * 1 = no flag value
62  * 2 = flag with value
63  */
64 #define __CTR_FLAG_SYNC			0  /* 1 */ /* Not with raid0! */
65 #define __CTR_FLAG_NOSYNC		1  /* 1 */ /* Not with raid0! */
66 #define __CTR_FLAG_REBUILD		2  /* 2 */ /* Not with raid0! */
67 #define __CTR_FLAG_DAEMON_SLEEP		3  /* 2 */ /* Not with raid0! */
68 #define __CTR_FLAG_MIN_RECOVERY_RATE	4  /* 2 */ /* Not with raid0! */
69 #define __CTR_FLAG_MAX_RECOVERY_RATE	5  /* 2 */ /* Not with raid0! */
70 #define __CTR_FLAG_MAX_WRITE_BEHIND	6  /* 2 */ /* Only with raid1! */
71 #define __CTR_FLAG_WRITE_MOSTLY		7  /* 2 */ /* Only with raid1! */
72 #define __CTR_FLAG_STRIPE_CACHE		8  /* 2 */ /* Only with raid4/5/6! */
73 #define __CTR_FLAG_REGION_SIZE		9  /* 2 */ /* Not with raid0! */
74 #define __CTR_FLAG_RAID10_COPIES	10 /* 2 */ /* Only with raid10 */
75 #define __CTR_FLAG_RAID10_FORMAT	11 /* 2 */ /* Only with raid10 */
76 /* New for v1.9.0 */
77 #define __CTR_FLAG_DELTA_DISKS		12 /* 2 */ /* Only with reshapable raid1/4/5/6/10! */
78 #define __CTR_FLAG_DATA_OFFSET		13 /* 2 */ /* Only with reshapable raid4/5/6/10! */
79 #define __CTR_FLAG_RAID10_USE_NEAR_SETS 14 /* 2 */ /* Only with raid10! */
80 
81 /* New for v1.10.0 */
82 #define __CTR_FLAG_JOURNAL_DEV		15 /* 2 */ /* Only with raid4/5/6 (journal device)! */
83 
84 /* New for v1.11.1 */
85 #define __CTR_FLAG_JOURNAL_MODE		16 /* 2 */ /* Only with raid4/5/6 (journal mode)! */
86 
87 /*
88  * Flags for rs->ctr_flags field.
89  */
90 #define CTR_FLAG_SYNC			(1 << __CTR_FLAG_SYNC)
91 #define CTR_FLAG_NOSYNC			(1 << __CTR_FLAG_NOSYNC)
92 #define CTR_FLAG_REBUILD		(1 << __CTR_FLAG_REBUILD)
93 #define CTR_FLAG_DAEMON_SLEEP		(1 << __CTR_FLAG_DAEMON_SLEEP)
94 #define CTR_FLAG_MIN_RECOVERY_RATE	(1 << __CTR_FLAG_MIN_RECOVERY_RATE)
95 #define CTR_FLAG_MAX_RECOVERY_RATE	(1 << __CTR_FLAG_MAX_RECOVERY_RATE)
96 #define CTR_FLAG_MAX_WRITE_BEHIND	(1 << __CTR_FLAG_MAX_WRITE_BEHIND)
97 #define CTR_FLAG_WRITE_MOSTLY		(1 << __CTR_FLAG_WRITE_MOSTLY)
98 #define CTR_FLAG_STRIPE_CACHE		(1 << __CTR_FLAG_STRIPE_CACHE)
99 #define CTR_FLAG_REGION_SIZE		(1 << __CTR_FLAG_REGION_SIZE)
100 #define CTR_FLAG_RAID10_COPIES		(1 << __CTR_FLAG_RAID10_COPIES)
101 #define CTR_FLAG_RAID10_FORMAT		(1 << __CTR_FLAG_RAID10_FORMAT)
102 #define CTR_FLAG_DELTA_DISKS		(1 << __CTR_FLAG_DELTA_DISKS)
103 #define CTR_FLAG_DATA_OFFSET		(1 << __CTR_FLAG_DATA_OFFSET)
104 #define CTR_FLAG_RAID10_USE_NEAR_SETS	(1 << __CTR_FLAG_RAID10_USE_NEAR_SETS)
105 #define CTR_FLAG_JOURNAL_DEV		(1 << __CTR_FLAG_JOURNAL_DEV)
106 #define CTR_FLAG_JOURNAL_MODE		(1 << __CTR_FLAG_JOURNAL_MODE)
107 
108 /*
109  * Definitions of various constructor flags to
110  * be used in checks of valid / invalid flags
111  * per raid level.
112  */
113 /* Define all any sync flags */
114 #define	CTR_FLAGS_ANY_SYNC		(CTR_FLAG_SYNC | CTR_FLAG_NOSYNC)
115 
116 /* Define flags for options without argument (e.g. 'nosync') */
117 #define	CTR_FLAG_OPTIONS_NO_ARGS	(CTR_FLAGS_ANY_SYNC | \
118 					 CTR_FLAG_RAID10_USE_NEAR_SETS)
119 
120 /* Define flags for options with one argument (e.g. 'delta_disks +2') */
121 #define CTR_FLAG_OPTIONS_ONE_ARG (CTR_FLAG_REBUILD | \
122 				  CTR_FLAG_WRITE_MOSTLY | \
123 				  CTR_FLAG_DAEMON_SLEEP | \
124 				  CTR_FLAG_MIN_RECOVERY_RATE | \
125 				  CTR_FLAG_MAX_RECOVERY_RATE | \
126 				  CTR_FLAG_MAX_WRITE_BEHIND | \
127 				  CTR_FLAG_STRIPE_CACHE | \
128 				  CTR_FLAG_REGION_SIZE | \
129 				  CTR_FLAG_RAID10_COPIES | \
130 				  CTR_FLAG_RAID10_FORMAT | \
131 				  CTR_FLAG_DELTA_DISKS | \
132 				  CTR_FLAG_DATA_OFFSET)
133 
134 /* Valid options definitions per raid level... */
135 
136 /* "raid0" does only accept data offset */
137 #define RAID0_VALID_FLAGS	(CTR_FLAG_DATA_OFFSET)
138 
139 /* "raid1" does not accept stripe cache, data offset, delta_disks or any raid10 options */
140 #define RAID1_VALID_FLAGS	(CTR_FLAGS_ANY_SYNC | \
141 				 CTR_FLAG_REBUILD | \
142 				 CTR_FLAG_WRITE_MOSTLY | \
143 				 CTR_FLAG_DAEMON_SLEEP | \
144 				 CTR_FLAG_MIN_RECOVERY_RATE | \
145 				 CTR_FLAG_MAX_RECOVERY_RATE | \
146 				 CTR_FLAG_MAX_WRITE_BEHIND | \
147 				 CTR_FLAG_REGION_SIZE | \
148 				 CTR_FLAG_DELTA_DISKS | \
149 				 CTR_FLAG_DATA_OFFSET)
150 
151 /* "raid10" does not accept any raid1 or stripe cache options */
152 #define RAID10_VALID_FLAGS	(CTR_FLAGS_ANY_SYNC | \
153 				 CTR_FLAG_REBUILD | \
154 				 CTR_FLAG_DAEMON_SLEEP | \
155 				 CTR_FLAG_MIN_RECOVERY_RATE | \
156 				 CTR_FLAG_MAX_RECOVERY_RATE | \
157 				 CTR_FLAG_REGION_SIZE | \
158 				 CTR_FLAG_RAID10_COPIES | \
159 				 CTR_FLAG_RAID10_FORMAT | \
160 				 CTR_FLAG_DELTA_DISKS | \
161 				 CTR_FLAG_DATA_OFFSET | \
162 				 CTR_FLAG_RAID10_USE_NEAR_SETS)
163 
164 /*
165  * "raid4/5/6" do not accept any raid1 or raid10 specific options
166  *
167  * "raid6" does not accept "nosync", because it is not guaranteed
168  * that both parity and q-syndrome are being written properly with
169  * any writes
170  */
171 #define RAID45_VALID_FLAGS	(CTR_FLAGS_ANY_SYNC | \
172 				 CTR_FLAG_REBUILD | \
173 				 CTR_FLAG_DAEMON_SLEEP | \
174 				 CTR_FLAG_MIN_RECOVERY_RATE | \
175 				 CTR_FLAG_MAX_RECOVERY_RATE | \
176 				 CTR_FLAG_STRIPE_CACHE | \
177 				 CTR_FLAG_REGION_SIZE | \
178 				 CTR_FLAG_DELTA_DISKS | \
179 				 CTR_FLAG_DATA_OFFSET | \
180 				 CTR_FLAG_JOURNAL_DEV | \
181 				 CTR_FLAG_JOURNAL_MODE)
182 
183 #define RAID6_VALID_FLAGS	(CTR_FLAG_SYNC | \
184 				 CTR_FLAG_REBUILD | \
185 				 CTR_FLAG_DAEMON_SLEEP | \
186 				 CTR_FLAG_MIN_RECOVERY_RATE | \
187 				 CTR_FLAG_MAX_RECOVERY_RATE | \
188 				 CTR_FLAG_STRIPE_CACHE | \
189 				 CTR_FLAG_REGION_SIZE | \
190 				 CTR_FLAG_DELTA_DISKS | \
191 				 CTR_FLAG_DATA_OFFSET | \
192 				 CTR_FLAG_JOURNAL_DEV | \
193 				 CTR_FLAG_JOURNAL_MODE)
194 /* ...valid options definitions per raid level */
195 
196 /*
197  * Flags for rs->runtime_flags field
198  * (RT_FLAG prefix meaning "runtime flag")
199  *
200  * These are all internal and used to define runtime state,
201  * e.g. to prevent another resume from preresume processing
202  * the raid set all over again.
203  */
204 #define RT_FLAG_RS_PRERESUMED		0
205 #define RT_FLAG_RS_RESUMED		1
206 #define RT_FLAG_RS_BITMAP_LOADED	2
207 #define RT_FLAG_UPDATE_SBS		3
208 #define RT_FLAG_RESHAPE_RS		4
209 #define RT_FLAG_RS_SUSPENDED		5
210 #define RT_FLAG_RS_IN_SYNC		6
211 #define RT_FLAG_RS_RESYNCING		7
212 
213 /* Array elements of 64 bit needed for rebuild/failed disk bits */
214 #define DISKS_ARRAY_ELEMS ((MAX_RAID_DEVICES + (sizeof(uint64_t) * 8 - 1)) / sizeof(uint64_t) / 8)
215 
216 /*
217  * raid set level, layout and chunk sectors backup/restore
218  */
219 struct rs_layout {
220 	int new_level;
221 	int new_layout;
222 	int new_chunk_sectors;
223 };
224 
225 struct raid_set {
226 	struct dm_target *ti;
227 
228 	uint32_t stripe_cache_entries;
229 	unsigned long ctr_flags;
230 	unsigned long runtime_flags;
231 
232 	uint64_t rebuild_disks[DISKS_ARRAY_ELEMS];
233 
234 	int raid_disks;
235 	int delta_disks;
236 	int data_offset;
237 	int raid10_copies;
238 	int requested_bitmap_chunk_sectors;
239 
240 	struct mddev md;
241 	struct raid_type *raid_type;
242 	struct dm_target_callbacks callbacks;
243 
244 	/* Optional raid4/5/6 journal device */
245 	struct journal_dev {
246 		struct dm_dev *dev;
247 		struct md_rdev rdev;
248 		int mode;
249 	} journal_dev;
250 
251 	struct raid_dev dev[0];
252 };
253 
254 static void rs_config_backup(struct raid_set *rs, struct rs_layout *l)
255 {
256 	struct mddev *mddev = &rs->md;
257 
258 	l->new_level = mddev->new_level;
259 	l->new_layout = mddev->new_layout;
260 	l->new_chunk_sectors = mddev->new_chunk_sectors;
261 }
262 
263 static void rs_config_restore(struct raid_set *rs, struct rs_layout *l)
264 {
265 	struct mddev *mddev = &rs->md;
266 
267 	mddev->new_level = l->new_level;
268 	mddev->new_layout = l->new_layout;
269 	mddev->new_chunk_sectors = l->new_chunk_sectors;
270 }
271 
272 /* raid10 algorithms (i.e. formats) */
273 #define	ALGORITHM_RAID10_DEFAULT	0
274 #define	ALGORITHM_RAID10_NEAR		1
275 #define	ALGORITHM_RAID10_OFFSET		2
276 #define	ALGORITHM_RAID10_FAR		3
277 
278 /* Supported raid types and properties. */
279 static struct raid_type {
280 	const char *name;		/* RAID algorithm. */
281 	const char *descr;		/* Descriptor text for logging. */
282 	const unsigned int parity_devs;	/* # of parity devices. */
283 	const unsigned int minimal_devs;/* minimal # of devices in set. */
284 	const unsigned int level;	/* RAID level. */
285 	const unsigned int algorithm;	/* RAID algorithm. */
286 } raid_types[] = {
287 	{"raid0",	  "raid0 (striping)",			    0, 2, 0,  0 /* NONE */},
288 	{"raid1",	  "raid1 (mirroring)",			    0, 2, 1,  0 /* NONE */},
289 	{"raid10_far",	  "raid10 far (striped mirrors)",	    0, 2, 10, ALGORITHM_RAID10_FAR},
290 	{"raid10_offset", "raid10 offset (striped mirrors)",	    0, 2, 10, ALGORITHM_RAID10_OFFSET},
291 	{"raid10_near",	  "raid10 near (striped mirrors)",	    0, 2, 10, ALGORITHM_RAID10_NEAR},
292 	{"raid10",	  "raid10 (striped mirrors)",		    0, 2, 10, ALGORITHM_RAID10_DEFAULT},
293 	{"raid4",	  "raid4 (dedicated first parity disk)",    1, 2, 5,  ALGORITHM_PARITY_0}, /* raid4 layout = raid5_0 */
294 	{"raid5_n",	  "raid5 (dedicated last parity disk)",	    1, 2, 5,  ALGORITHM_PARITY_N},
295 	{"raid5_ls",	  "raid5 (left symmetric)",		    1, 2, 5,  ALGORITHM_LEFT_SYMMETRIC},
296 	{"raid5_rs",	  "raid5 (right symmetric)",		    1, 2, 5,  ALGORITHM_RIGHT_SYMMETRIC},
297 	{"raid5_la",	  "raid5 (left asymmetric)",		    1, 2, 5,  ALGORITHM_LEFT_ASYMMETRIC},
298 	{"raid5_ra",	  "raid5 (right asymmetric)",		    1, 2, 5,  ALGORITHM_RIGHT_ASYMMETRIC},
299 	{"raid6_zr",	  "raid6 (zero restart)",		    2, 4, 6,  ALGORITHM_ROTATING_ZERO_RESTART},
300 	{"raid6_nr",	  "raid6 (N restart)",			    2, 4, 6,  ALGORITHM_ROTATING_N_RESTART},
301 	{"raid6_nc",	  "raid6 (N continue)",			    2, 4, 6,  ALGORITHM_ROTATING_N_CONTINUE},
302 	{"raid6_n_6",	  "raid6 (dedicated parity/Q n/6)",	    2, 4, 6,  ALGORITHM_PARITY_N_6},
303 	{"raid6_ls_6",	  "raid6 (left symmetric dedicated Q 6)",   2, 4, 6,  ALGORITHM_LEFT_SYMMETRIC_6},
304 	{"raid6_rs_6",	  "raid6 (right symmetric dedicated Q 6)",  2, 4, 6,  ALGORITHM_RIGHT_SYMMETRIC_6},
305 	{"raid6_la_6",	  "raid6 (left asymmetric dedicated Q 6)",  2, 4, 6,  ALGORITHM_LEFT_ASYMMETRIC_6},
306 	{"raid6_ra_6",	  "raid6 (right asymmetric dedicated Q 6)", 2, 4, 6,  ALGORITHM_RIGHT_ASYMMETRIC_6}
307 };
308 
309 /* True, if @v is in inclusive range [@min, @max] */
310 static bool __within_range(long v, long min, long max)
311 {
312 	return v >= min && v <= max;
313 }
314 
315 /* All table line arguments are defined here */
316 static struct arg_name_flag {
317 	const unsigned long flag;
318 	const char *name;
319 } __arg_name_flags[] = {
320 	{ CTR_FLAG_SYNC, "sync"},
321 	{ CTR_FLAG_NOSYNC, "nosync"},
322 	{ CTR_FLAG_REBUILD, "rebuild"},
323 	{ CTR_FLAG_DAEMON_SLEEP, "daemon_sleep"},
324 	{ CTR_FLAG_MIN_RECOVERY_RATE, "min_recovery_rate"},
325 	{ CTR_FLAG_MAX_RECOVERY_RATE, "max_recovery_rate"},
326 	{ CTR_FLAG_MAX_WRITE_BEHIND, "max_write_behind"},
327 	{ CTR_FLAG_WRITE_MOSTLY, "write_mostly"},
328 	{ CTR_FLAG_STRIPE_CACHE, "stripe_cache"},
329 	{ CTR_FLAG_REGION_SIZE, "region_size"},
330 	{ CTR_FLAG_RAID10_COPIES, "raid10_copies"},
331 	{ CTR_FLAG_RAID10_FORMAT, "raid10_format"},
332 	{ CTR_FLAG_DATA_OFFSET, "data_offset"},
333 	{ CTR_FLAG_DELTA_DISKS, "delta_disks"},
334 	{ CTR_FLAG_RAID10_USE_NEAR_SETS, "raid10_use_near_sets"},
335 	{ CTR_FLAG_JOURNAL_DEV, "journal_dev" },
336 	{ CTR_FLAG_JOURNAL_MODE, "journal_mode" },
337 };
338 
339 /* Return argument name string for given @flag */
340 static const char *dm_raid_arg_name_by_flag(const uint32_t flag)
341 {
342 	if (hweight32(flag) == 1) {
343 		struct arg_name_flag *anf = __arg_name_flags + ARRAY_SIZE(__arg_name_flags);
344 
345 		while (anf-- > __arg_name_flags)
346 			if (flag & anf->flag)
347 				return anf->name;
348 
349 	} else
350 		DMERR("%s called with more than one flag!", __func__);
351 
352 	return NULL;
353 }
354 
355 /* Define correlation of raid456 journal cache modes and dm-raid target line parameters */
356 static struct {
357 	const int mode;
358 	const char *param;
359 } _raid456_journal_mode[] = {
360 	{ R5C_JOURNAL_MODE_WRITE_THROUGH , "writethrough" },
361 	{ R5C_JOURNAL_MODE_WRITE_BACK    , "writeback" }
362 };
363 
364 /* Return MD raid4/5/6 journal mode for dm @journal_mode one */
365 static int dm_raid_journal_mode_to_md(const char *mode)
366 {
367 	int m = ARRAY_SIZE(_raid456_journal_mode);
368 
369 	while (m--)
370 		if (!strcasecmp(mode, _raid456_journal_mode[m].param))
371 			return _raid456_journal_mode[m].mode;
372 
373 	return -EINVAL;
374 }
375 
376 /* Return dm-raid raid4/5/6 journal mode string for @mode */
377 static const char *md_journal_mode_to_dm_raid(const int mode)
378 {
379 	int m = ARRAY_SIZE(_raid456_journal_mode);
380 
381 	while (m--)
382 		if (mode == _raid456_journal_mode[m].mode)
383 			return _raid456_journal_mode[m].param;
384 
385 	return "unknown";
386 }
387 
388 /*
389  * Bool helpers to test for various raid levels of a raid set.
390  * It's level as reported by the superblock rather than
391  * the requested raid_type passed to the constructor.
392  */
393 /* Return true, if raid set in @rs is raid0 */
394 static bool rs_is_raid0(struct raid_set *rs)
395 {
396 	return !rs->md.level;
397 }
398 
399 /* Return true, if raid set in @rs is raid1 */
400 static bool rs_is_raid1(struct raid_set *rs)
401 {
402 	return rs->md.level == 1;
403 }
404 
405 /* Return true, if raid set in @rs is raid10 */
406 static bool rs_is_raid10(struct raid_set *rs)
407 {
408 	return rs->md.level == 10;
409 }
410 
411 /* Return true, if raid set in @rs is level 6 */
412 static bool rs_is_raid6(struct raid_set *rs)
413 {
414 	return rs->md.level == 6;
415 }
416 
417 /* Return true, if raid set in @rs is level 4, 5 or 6 */
418 static bool rs_is_raid456(struct raid_set *rs)
419 {
420 	return __within_range(rs->md.level, 4, 6);
421 }
422 
423 /* Return true, if raid set in @rs is reshapable */
424 static bool __is_raid10_far(int layout);
425 static bool rs_is_reshapable(struct raid_set *rs)
426 {
427 	return rs_is_raid456(rs) ||
428 	       (rs_is_raid10(rs) && !__is_raid10_far(rs->md.new_layout));
429 }
430 
431 /* Return true, if raid set in @rs is recovering */
432 static bool rs_is_recovering(struct raid_set *rs)
433 {
434 	return rs->md.recovery_cp < rs->md.dev_sectors;
435 }
436 
437 /* Return true, if raid set in @rs is reshaping */
438 static bool rs_is_reshaping(struct raid_set *rs)
439 {
440 	return rs->md.reshape_position != MaxSector;
441 }
442 
443 /*
444  * bool helpers to test for various raid levels of a raid type @rt
445  */
446 
447 /* Return true, if raid type in @rt is raid0 */
448 static bool rt_is_raid0(struct raid_type *rt)
449 {
450 	return !rt->level;
451 }
452 
453 /* Return true, if raid type in @rt is raid1 */
454 static bool rt_is_raid1(struct raid_type *rt)
455 {
456 	return rt->level == 1;
457 }
458 
459 /* Return true, if raid type in @rt is raid10 */
460 static bool rt_is_raid10(struct raid_type *rt)
461 {
462 	return rt->level == 10;
463 }
464 
465 /* Return true, if raid type in @rt is raid4/5 */
466 static bool rt_is_raid45(struct raid_type *rt)
467 {
468 	return __within_range(rt->level, 4, 5);
469 }
470 
471 /* Return true, if raid type in @rt is raid6 */
472 static bool rt_is_raid6(struct raid_type *rt)
473 {
474 	return rt->level == 6;
475 }
476 
477 /* Return true, if raid type in @rt is raid4/5/6 */
478 static bool rt_is_raid456(struct raid_type *rt)
479 {
480 	return __within_range(rt->level, 4, 6);
481 }
482 /* END: raid level bools */
483 
484 /* Return valid ctr flags for the raid level of @rs */
485 static unsigned long __valid_flags(struct raid_set *rs)
486 {
487 	if (rt_is_raid0(rs->raid_type))
488 		return RAID0_VALID_FLAGS;
489 	else if (rt_is_raid1(rs->raid_type))
490 		return RAID1_VALID_FLAGS;
491 	else if (rt_is_raid10(rs->raid_type))
492 		return RAID10_VALID_FLAGS;
493 	else if (rt_is_raid45(rs->raid_type))
494 		return RAID45_VALID_FLAGS;
495 	else if (rt_is_raid6(rs->raid_type))
496 		return RAID6_VALID_FLAGS;
497 
498 	return 0;
499 }
500 
501 /*
502  * Check for valid flags set on @rs
503  *
504  * Has to be called after parsing of the ctr flags!
505  */
506 static int rs_check_for_valid_flags(struct raid_set *rs)
507 {
508 	if (rs->ctr_flags & ~__valid_flags(rs)) {
509 		rs->ti->error = "Invalid flags combination";
510 		return -EINVAL;
511 	}
512 
513 	return 0;
514 }
515 
516 /* MD raid10 bit definitions and helpers */
517 #define RAID10_OFFSET			(1 << 16) /* stripes with data copies area adjacent on devices */
518 #define RAID10_BROCKEN_USE_FAR_SETS	(1 << 17) /* Broken in raid10.c: use sets instead of whole stripe rotation */
519 #define RAID10_USE_FAR_SETS		(1 << 18) /* Use sets instead of whole stripe rotation */
520 #define RAID10_FAR_COPIES_SHIFT		8	  /* raid10 # far copies shift (2nd byte of layout) */
521 
522 /* Return md raid10 near copies for @layout */
523 static unsigned int __raid10_near_copies(int layout)
524 {
525 	return layout & 0xFF;
526 }
527 
528 /* Return md raid10 far copies for @layout */
529 static unsigned int __raid10_far_copies(int layout)
530 {
531 	return __raid10_near_copies(layout >> RAID10_FAR_COPIES_SHIFT);
532 }
533 
534 /* Return true if md raid10 offset for @layout */
535 static bool __is_raid10_offset(int layout)
536 {
537 	return !!(layout & RAID10_OFFSET);
538 }
539 
540 /* Return true if md raid10 near for @layout */
541 static bool __is_raid10_near(int layout)
542 {
543 	return !__is_raid10_offset(layout) && __raid10_near_copies(layout) > 1;
544 }
545 
546 /* Return true if md raid10 far for @layout */
547 static bool __is_raid10_far(int layout)
548 {
549 	return !__is_raid10_offset(layout) && __raid10_far_copies(layout) > 1;
550 }
551 
552 /* Return md raid10 layout string for @layout */
553 static const char *raid10_md_layout_to_format(int layout)
554 {
555 	/*
556 	 * Bit 16 stands for "offset"
557 	 * (i.e. adjacent stripes hold copies)
558 	 *
559 	 * Refer to MD's raid10.c for details
560 	 */
561 	if (__is_raid10_offset(layout))
562 		return "offset";
563 
564 	if (__raid10_near_copies(layout) > 1)
565 		return "near";
566 
567 	if (__raid10_far_copies(layout) > 1)
568 		return "far";
569 
570 	return "unknown";
571 }
572 
573 /* Return md raid10 algorithm for @name */
574 static int raid10_name_to_format(const char *name)
575 {
576 	if (!strcasecmp(name, "near"))
577 		return ALGORITHM_RAID10_NEAR;
578 	else if (!strcasecmp(name, "offset"))
579 		return ALGORITHM_RAID10_OFFSET;
580 	else if (!strcasecmp(name, "far"))
581 		return ALGORITHM_RAID10_FAR;
582 
583 	return -EINVAL;
584 }
585 
586 /* Return md raid10 copies for @layout */
587 static unsigned int raid10_md_layout_to_copies(int layout)
588 {
589 	return max(__raid10_near_copies(layout), __raid10_far_copies(layout));
590 }
591 
592 /* Return md raid10 format id for @format string */
593 static int raid10_format_to_md_layout(struct raid_set *rs,
594 				      unsigned int algorithm,
595 				      unsigned int copies)
596 {
597 	unsigned int n = 1, f = 1, r = 0;
598 
599 	/*
600 	 * MD resilienece flaw:
601 	 *
602 	 * enabling use_far_sets for far/offset formats causes copies
603 	 * to be colocated on the same devs together with their origins!
604 	 *
605 	 * -> disable it for now in the definition above
606 	 */
607 	if (algorithm == ALGORITHM_RAID10_DEFAULT ||
608 	    algorithm == ALGORITHM_RAID10_NEAR)
609 		n = copies;
610 
611 	else if (algorithm == ALGORITHM_RAID10_OFFSET) {
612 		f = copies;
613 		r = RAID10_OFFSET;
614 		if (!test_bit(__CTR_FLAG_RAID10_USE_NEAR_SETS, &rs->ctr_flags))
615 			r |= RAID10_USE_FAR_SETS;
616 
617 	} else if (algorithm == ALGORITHM_RAID10_FAR) {
618 		f = copies;
619 		r = !RAID10_OFFSET;
620 		if (!test_bit(__CTR_FLAG_RAID10_USE_NEAR_SETS, &rs->ctr_flags))
621 			r |= RAID10_USE_FAR_SETS;
622 
623 	} else
624 		return -EINVAL;
625 
626 	return r | (f << RAID10_FAR_COPIES_SHIFT) | n;
627 }
628 /* END: MD raid10 bit definitions and helpers */
629 
630 /* Check for any of the raid10 algorithms */
631 static bool __got_raid10(struct raid_type *rtp, const int layout)
632 {
633 	if (rtp->level == 10) {
634 		switch (rtp->algorithm) {
635 		case ALGORITHM_RAID10_DEFAULT:
636 		case ALGORITHM_RAID10_NEAR:
637 			return __is_raid10_near(layout);
638 		case ALGORITHM_RAID10_OFFSET:
639 			return __is_raid10_offset(layout);
640 		case ALGORITHM_RAID10_FAR:
641 			return __is_raid10_far(layout);
642 		default:
643 			break;
644 		}
645 	}
646 
647 	return false;
648 }
649 
650 /* Return raid_type for @name */
651 static struct raid_type *get_raid_type(const char *name)
652 {
653 	struct raid_type *rtp = raid_types + ARRAY_SIZE(raid_types);
654 
655 	while (rtp-- > raid_types)
656 		if (!strcasecmp(rtp->name, name))
657 			return rtp;
658 
659 	return NULL;
660 }
661 
662 /* Return raid_type for @name based derived from @level and @layout */
663 static struct raid_type *get_raid_type_by_ll(const int level, const int layout)
664 {
665 	struct raid_type *rtp = raid_types + ARRAY_SIZE(raid_types);
666 
667 	while (rtp-- > raid_types) {
668 		/* RAID10 special checks based on @layout flags/properties */
669 		if (rtp->level == level &&
670 		    (__got_raid10(rtp, layout) || rtp->algorithm == layout))
671 			return rtp;
672 	}
673 
674 	return NULL;
675 }
676 
677 /* Adjust rdev sectors */
678 static void rs_set_rdev_sectors(struct raid_set *rs)
679 {
680 	struct mddev *mddev = &rs->md;
681 	struct md_rdev *rdev;
682 
683 	/*
684 	 * raid10 sets rdev->sector to the device size, which
685 	 * is unintended in case of out-of-place reshaping
686 	 */
687 	rdev_for_each(rdev, mddev)
688 		if (!test_bit(Journal, &rdev->flags))
689 			rdev->sectors = mddev->dev_sectors;
690 }
691 
692 /*
693  * Change bdev capacity of @rs in case of a disk add/remove reshape
694  */
695 static void rs_set_capacity(struct raid_set *rs)
696 {
697 	struct gendisk *gendisk = dm_disk(dm_table_get_md(rs->ti->table));
698 
699 	set_capacity(gendisk, rs->md.array_sectors);
700 	revalidate_disk(gendisk);
701 }
702 
703 /*
704  * Set the mddev properties in @rs to the current
705  * ones retrieved from the freshest superblock
706  */
707 static void rs_set_cur(struct raid_set *rs)
708 {
709 	struct mddev *mddev = &rs->md;
710 
711 	mddev->new_level = mddev->level;
712 	mddev->new_layout = mddev->layout;
713 	mddev->new_chunk_sectors = mddev->chunk_sectors;
714 }
715 
716 /*
717  * Set the mddev properties in @rs to the new
718  * ones requested by the ctr
719  */
720 static void rs_set_new(struct raid_set *rs)
721 {
722 	struct mddev *mddev = &rs->md;
723 
724 	mddev->level = mddev->new_level;
725 	mddev->layout = mddev->new_layout;
726 	mddev->chunk_sectors = mddev->new_chunk_sectors;
727 	mddev->raid_disks = rs->raid_disks;
728 	mddev->delta_disks = 0;
729 }
730 
731 static struct raid_set *raid_set_alloc(struct dm_target *ti, struct raid_type *raid_type,
732 				       unsigned int raid_devs)
733 {
734 	unsigned int i;
735 	struct raid_set *rs;
736 
737 	if (raid_devs <= raid_type->parity_devs) {
738 		ti->error = "Insufficient number of devices";
739 		return ERR_PTR(-EINVAL);
740 	}
741 
742 	rs = kzalloc(struct_size(rs, dev, raid_devs), GFP_KERNEL);
743 	if (!rs) {
744 		ti->error = "Cannot allocate raid context";
745 		return ERR_PTR(-ENOMEM);
746 	}
747 
748 	mddev_init(&rs->md);
749 
750 	rs->raid_disks = raid_devs;
751 	rs->delta_disks = 0;
752 
753 	rs->ti = ti;
754 	rs->raid_type = raid_type;
755 	rs->stripe_cache_entries = 256;
756 	rs->md.raid_disks = raid_devs;
757 	rs->md.level = raid_type->level;
758 	rs->md.new_level = rs->md.level;
759 	rs->md.layout = raid_type->algorithm;
760 	rs->md.new_layout = rs->md.layout;
761 	rs->md.delta_disks = 0;
762 	rs->md.recovery_cp = MaxSector;
763 
764 	for (i = 0; i < raid_devs; i++)
765 		md_rdev_init(&rs->dev[i].rdev);
766 
767 	/*
768 	 * Remaining items to be initialized by further RAID params:
769 	 *  rs->md.persistent
770 	 *  rs->md.external
771 	 *  rs->md.chunk_sectors
772 	 *  rs->md.new_chunk_sectors
773 	 *  rs->md.dev_sectors
774 	 */
775 
776 	return rs;
777 }
778 
779 /* Free all @rs allocations */
780 static void raid_set_free(struct raid_set *rs)
781 {
782 	int i;
783 
784 	if (rs->journal_dev.dev) {
785 		md_rdev_clear(&rs->journal_dev.rdev);
786 		dm_put_device(rs->ti, rs->journal_dev.dev);
787 	}
788 
789 	for (i = 0; i < rs->raid_disks; i++) {
790 		if (rs->dev[i].meta_dev)
791 			dm_put_device(rs->ti, rs->dev[i].meta_dev);
792 		md_rdev_clear(&rs->dev[i].rdev);
793 		if (rs->dev[i].data_dev)
794 			dm_put_device(rs->ti, rs->dev[i].data_dev);
795 	}
796 
797 	kfree(rs);
798 }
799 
800 /*
801  * For every device we have two words
802  *  <meta_dev>: meta device name or '-' if missing
803  *  <data_dev>: data device name or '-' if missing
804  *
805  * The following are permitted:
806  *    - -
807  *    - <data_dev>
808  *    <meta_dev> <data_dev>
809  *
810  * The following is not allowed:
811  *    <meta_dev> -
812  *
813  * This code parses those words.  If there is a failure,
814  * the caller must use raid_set_free() to unwind the operations.
815  */
816 static int parse_dev_params(struct raid_set *rs, struct dm_arg_set *as)
817 {
818 	int i;
819 	int rebuild = 0;
820 	int metadata_available = 0;
821 	int r = 0;
822 	const char *arg;
823 
824 	/* Put off the number of raid devices argument to get to dev pairs */
825 	arg = dm_shift_arg(as);
826 	if (!arg)
827 		return -EINVAL;
828 
829 	for (i = 0; i < rs->raid_disks; i++) {
830 		rs->dev[i].rdev.raid_disk = i;
831 
832 		rs->dev[i].meta_dev = NULL;
833 		rs->dev[i].data_dev = NULL;
834 
835 		/*
836 		 * There are no offsets initially.
837 		 * Out of place reshape will set them accordingly.
838 		 */
839 		rs->dev[i].rdev.data_offset = 0;
840 		rs->dev[i].rdev.new_data_offset = 0;
841 		rs->dev[i].rdev.mddev = &rs->md;
842 
843 		arg = dm_shift_arg(as);
844 		if (!arg)
845 			return -EINVAL;
846 
847 		if (strcmp(arg, "-")) {
848 			r = dm_get_device(rs->ti, arg, dm_table_get_mode(rs->ti->table),
849 					  &rs->dev[i].meta_dev);
850 			if (r) {
851 				rs->ti->error = "RAID metadata device lookup failure";
852 				return r;
853 			}
854 
855 			rs->dev[i].rdev.sb_page = alloc_page(GFP_KERNEL);
856 			if (!rs->dev[i].rdev.sb_page) {
857 				rs->ti->error = "Failed to allocate superblock page";
858 				return -ENOMEM;
859 			}
860 		}
861 
862 		arg = dm_shift_arg(as);
863 		if (!arg)
864 			return -EINVAL;
865 
866 		if (!strcmp(arg, "-")) {
867 			if (!test_bit(In_sync, &rs->dev[i].rdev.flags) &&
868 			    (!rs->dev[i].rdev.recovery_offset)) {
869 				rs->ti->error = "Drive designated for rebuild not specified";
870 				return -EINVAL;
871 			}
872 
873 			if (rs->dev[i].meta_dev) {
874 				rs->ti->error = "No data device supplied with metadata device";
875 				return -EINVAL;
876 			}
877 
878 			continue;
879 		}
880 
881 		r = dm_get_device(rs->ti, arg, dm_table_get_mode(rs->ti->table),
882 				  &rs->dev[i].data_dev);
883 		if (r) {
884 			rs->ti->error = "RAID device lookup failure";
885 			return r;
886 		}
887 
888 		if (rs->dev[i].meta_dev) {
889 			metadata_available = 1;
890 			rs->dev[i].rdev.meta_bdev = rs->dev[i].meta_dev->bdev;
891 		}
892 		rs->dev[i].rdev.bdev = rs->dev[i].data_dev->bdev;
893 		list_add_tail(&rs->dev[i].rdev.same_set, &rs->md.disks);
894 		if (!test_bit(In_sync, &rs->dev[i].rdev.flags))
895 			rebuild++;
896 	}
897 
898 	if (rs->journal_dev.dev)
899 		list_add_tail(&rs->journal_dev.rdev.same_set, &rs->md.disks);
900 
901 	if (metadata_available) {
902 		rs->md.external = 0;
903 		rs->md.persistent = 1;
904 		rs->md.major_version = 2;
905 	} else if (rebuild && !rs->md.recovery_cp) {
906 		/*
907 		 * Without metadata, we will not be able to tell if the array
908 		 * is in-sync or not - we must assume it is not.  Therefore,
909 		 * it is impossible to rebuild a drive.
910 		 *
911 		 * Even if there is metadata, the on-disk information may
912 		 * indicate that the array is not in-sync and it will then
913 		 * fail at that time.
914 		 *
915 		 * User could specify 'nosync' option if desperate.
916 		 */
917 		rs->ti->error = "Unable to rebuild drive while array is not in-sync";
918 		return -EINVAL;
919 	}
920 
921 	return 0;
922 }
923 
924 /*
925  * validate_region_size
926  * @rs
927  * @region_size:  region size in sectors.  If 0, pick a size (4MiB default).
928  *
929  * Set rs->md.bitmap_info.chunksize (which really refers to 'region size').
930  * Ensure that (ti->len/region_size < 2^21) - required by MD bitmap.
931  *
932  * Returns: 0 on success, -EINVAL on failure.
933  */
934 static int validate_region_size(struct raid_set *rs, unsigned long region_size)
935 {
936 	unsigned long min_region_size = rs->ti->len / (1 << 21);
937 
938 	if (rs_is_raid0(rs))
939 		return 0;
940 
941 	if (!region_size) {
942 		/*
943 		 * Choose a reasonable default.	 All figures in sectors.
944 		 */
945 		if (min_region_size > (1 << 13)) {
946 			/* If not a power of 2, make it the next power of 2 */
947 			region_size = roundup_pow_of_two(min_region_size);
948 			DMINFO("Choosing default region size of %lu sectors",
949 			       region_size);
950 		} else {
951 			DMINFO("Choosing default region size of 4MiB");
952 			region_size = 1 << 13; /* sectors */
953 		}
954 	} else {
955 		/*
956 		 * Validate user-supplied value.
957 		 */
958 		if (region_size > rs->ti->len) {
959 			rs->ti->error = "Supplied region size is too large";
960 			return -EINVAL;
961 		}
962 
963 		if (region_size < min_region_size) {
964 			DMERR("Supplied region_size (%lu sectors) below minimum (%lu)",
965 			      region_size, min_region_size);
966 			rs->ti->error = "Supplied region size is too small";
967 			return -EINVAL;
968 		}
969 
970 		if (!is_power_of_2(region_size)) {
971 			rs->ti->error = "Region size is not a power of 2";
972 			return -EINVAL;
973 		}
974 
975 		if (region_size < rs->md.chunk_sectors) {
976 			rs->ti->error = "Region size is smaller than the chunk size";
977 			return -EINVAL;
978 		}
979 	}
980 
981 	/*
982 	 * Convert sectors to bytes.
983 	 */
984 	rs->md.bitmap_info.chunksize = to_bytes(region_size);
985 
986 	return 0;
987 }
988 
989 /*
990  * validate_raid_redundancy
991  * @rs
992  *
993  * Determine if there are enough devices in the array that haven't
994  * failed (or are being rebuilt) to form a usable array.
995  *
996  * Returns: 0 on success, -EINVAL on failure.
997  */
998 static int validate_raid_redundancy(struct raid_set *rs)
999 {
1000 	unsigned int i, rebuild_cnt = 0;
1001 	unsigned int rebuilds_per_group = 0, copies;
1002 	unsigned int group_size, last_group_start;
1003 
1004 	for (i = 0; i < rs->md.raid_disks; i++)
1005 		if (!test_bit(In_sync, &rs->dev[i].rdev.flags) ||
1006 		    !rs->dev[i].rdev.sb_page)
1007 			rebuild_cnt++;
1008 
1009 	switch (rs->md.level) {
1010 	case 0:
1011 		break;
1012 	case 1:
1013 		if (rebuild_cnt >= rs->md.raid_disks)
1014 			goto too_many;
1015 		break;
1016 	case 4:
1017 	case 5:
1018 	case 6:
1019 		if (rebuild_cnt > rs->raid_type->parity_devs)
1020 			goto too_many;
1021 		break;
1022 	case 10:
1023 		copies = raid10_md_layout_to_copies(rs->md.new_layout);
1024 		if (copies < 2) {
1025 			DMERR("Bogus raid10 data copies < 2!");
1026 			return -EINVAL;
1027 		}
1028 
1029 		if (rebuild_cnt < copies)
1030 			break;
1031 
1032 		/*
1033 		 * It is possible to have a higher rebuild count for RAID10,
1034 		 * as long as the failed devices occur in different mirror
1035 		 * groups (i.e. different stripes).
1036 		 *
1037 		 * When checking "near" format, make sure no adjacent devices
1038 		 * have failed beyond what can be handled.  In addition to the
1039 		 * simple case where the number of devices is a multiple of the
1040 		 * number of copies, we must also handle cases where the number
1041 		 * of devices is not a multiple of the number of copies.
1042 		 * E.g.	   dev1 dev2 dev3 dev4 dev5
1043 		 *	    A	 A    B	   B	C
1044 		 *	    C	 D    D	   E	E
1045 		 */
1046 		if (__is_raid10_near(rs->md.new_layout)) {
1047 			for (i = 0; i < rs->md.raid_disks; i++) {
1048 				if (!(i % copies))
1049 					rebuilds_per_group = 0;
1050 				if ((!rs->dev[i].rdev.sb_page ||
1051 				    !test_bit(In_sync, &rs->dev[i].rdev.flags)) &&
1052 				    (++rebuilds_per_group >= copies))
1053 					goto too_many;
1054 			}
1055 			break;
1056 		}
1057 
1058 		/*
1059 		 * When checking "far" and "offset" formats, we need to ensure
1060 		 * that the device that holds its copy is not also dead or
1061 		 * being rebuilt.  (Note that "far" and "offset" formats only
1062 		 * support two copies right now.  These formats also only ever
1063 		 * use the 'use_far_sets' variant.)
1064 		 *
1065 		 * This check is somewhat complicated by the need to account
1066 		 * for arrays that are not a multiple of (far) copies.	This
1067 		 * results in the need to treat the last (potentially larger)
1068 		 * set differently.
1069 		 */
1070 		group_size = (rs->md.raid_disks / copies);
1071 		last_group_start = (rs->md.raid_disks / group_size) - 1;
1072 		last_group_start *= group_size;
1073 		for (i = 0; i < rs->md.raid_disks; i++) {
1074 			if (!(i % copies) && !(i > last_group_start))
1075 				rebuilds_per_group = 0;
1076 			if ((!rs->dev[i].rdev.sb_page ||
1077 			     !test_bit(In_sync, &rs->dev[i].rdev.flags)) &&
1078 			    (++rebuilds_per_group >= copies))
1079 					goto too_many;
1080 		}
1081 		break;
1082 	default:
1083 		if (rebuild_cnt)
1084 			return -EINVAL;
1085 	}
1086 
1087 	return 0;
1088 
1089 too_many:
1090 	return -EINVAL;
1091 }
1092 
1093 /*
1094  * Possible arguments are...
1095  *	<chunk_size> [optional_args]
1096  *
1097  * Argument definitions
1098  *    <chunk_size>			The number of sectors per disk that
1099  *					will form the "stripe"
1100  *    [[no]sync]			Force or prevent recovery of the
1101  *					entire array
1102  *    [rebuild <idx>]			Rebuild the drive indicated by the index
1103  *    [daemon_sleep <ms>]		Time between bitmap daemon work to
1104  *					clear bits
1105  *    [min_recovery_rate <kB/sec/disk>]	Throttle RAID initialization
1106  *    [max_recovery_rate <kB/sec/disk>]	Throttle RAID initialization
1107  *    [write_mostly <idx>]		Indicate a write mostly drive via index
1108  *    [max_write_behind <sectors>]	See '-write-behind=' (man mdadm)
1109  *    [stripe_cache <sectors>]		Stripe cache size for higher RAIDs
1110  *    [region_size <sectors>]		Defines granularity of bitmap
1111  *    [journal_dev <dev>]		raid4/5/6 journaling deviice
1112  *    					(i.e. write hole closing log)
1113  *
1114  * RAID10-only options:
1115  *    [raid10_copies <# copies>]	Number of copies.  (Default: 2)
1116  *    [raid10_format <near|far|offset>] Layout algorithm.  (Default: near)
1117  */
1118 static int parse_raid_params(struct raid_set *rs, struct dm_arg_set *as,
1119 			     unsigned int num_raid_params)
1120 {
1121 	int value, raid10_format = ALGORITHM_RAID10_DEFAULT;
1122 	unsigned int raid10_copies = 2;
1123 	unsigned int i, write_mostly = 0;
1124 	unsigned int region_size = 0;
1125 	sector_t max_io_len;
1126 	const char *arg, *key;
1127 	struct raid_dev *rd;
1128 	struct raid_type *rt = rs->raid_type;
1129 
1130 	arg = dm_shift_arg(as);
1131 	num_raid_params--; /* Account for chunk_size argument */
1132 
1133 	if (kstrtoint(arg, 10, &value) < 0) {
1134 		rs->ti->error = "Bad numerical argument given for chunk_size";
1135 		return -EINVAL;
1136 	}
1137 
1138 	/*
1139 	 * First, parse the in-order required arguments
1140 	 * "chunk_size" is the only argument of this type.
1141 	 */
1142 	if (rt_is_raid1(rt)) {
1143 		if (value)
1144 			DMERR("Ignoring chunk size parameter for RAID 1");
1145 		value = 0;
1146 	} else if (!is_power_of_2(value)) {
1147 		rs->ti->error = "Chunk size must be a power of 2";
1148 		return -EINVAL;
1149 	} else if (value < 8) {
1150 		rs->ti->error = "Chunk size value is too small";
1151 		return -EINVAL;
1152 	}
1153 
1154 	rs->md.new_chunk_sectors = rs->md.chunk_sectors = value;
1155 
1156 	/*
1157 	 * We set each individual device as In_sync with a completed
1158 	 * 'recovery_offset'.  If there has been a device failure or
1159 	 * replacement then one of the following cases applies:
1160 	 *
1161 	 *   1) User specifies 'rebuild'.
1162 	 *	- Device is reset when param is read.
1163 	 *   2) A new device is supplied.
1164 	 *	- No matching superblock found, resets device.
1165 	 *   3) Device failure was transient and returns on reload.
1166 	 *	- Failure noticed, resets device for bitmap replay.
1167 	 *   4) Device hadn't completed recovery after previous failure.
1168 	 *	- Superblock is read and overrides recovery_offset.
1169 	 *
1170 	 * What is found in the superblocks of the devices is always
1171 	 * authoritative, unless 'rebuild' or '[no]sync' was specified.
1172 	 */
1173 	for (i = 0; i < rs->raid_disks; i++) {
1174 		set_bit(In_sync, &rs->dev[i].rdev.flags);
1175 		rs->dev[i].rdev.recovery_offset = MaxSector;
1176 	}
1177 
1178 	/*
1179 	 * Second, parse the unordered optional arguments
1180 	 */
1181 	for (i = 0; i < num_raid_params; i++) {
1182 		key = dm_shift_arg(as);
1183 		if (!key) {
1184 			rs->ti->error = "Not enough raid parameters given";
1185 			return -EINVAL;
1186 		}
1187 
1188 		if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_NOSYNC))) {
1189 			if (test_and_set_bit(__CTR_FLAG_NOSYNC, &rs->ctr_flags)) {
1190 				rs->ti->error = "Only one 'nosync' argument allowed";
1191 				return -EINVAL;
1192 			}
1193 			continue;
1194 		}
1195 		if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_SYNC))) {
1196 			if (test_and_set_bit(__CTR_FLAG_SYNC, &rs->ctr_flags)) {
1197 				rs->ti->error = "Only one 'sync' argument allowed";
1198 				return -EINVAL;
1199 			}
1200 			continue;
1201 		}
1202 		if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_RAID10_USE_NEAR_SETS))) {
1203 			if (test_and_set_bit(__CTR_FLAG_RAID10_USE_NEAR_SETS, &rs->ctr_flags)) {
1204 				rs->ti->error = "Only one 'raid10_use_new_sets' argument allowed";
1205 				return -EINVAL;
1206 			}
1207 			continue;
1208 		}
1209 
1210 		arg = dm_shift_arg(as);
1211 		i++; /* Account for the argument pairs */
1212 		if (!arg) {
1213 			rs->ti->error = "Wrong number of raid parameters given";
1214 			return -EINVAL;
1215 		}
1216 
1217 		/*
1218 		 * Parameters that take a string value are checked here.
1219 		 */
1220 		/* "raid10_format {near|offset|far} */
1221 		if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_RAID10_FORMAT))) {
1222 			if (test_and_set_bit(__CTR_FLAG_RAID10_FORMAT, &rs->ctr_flags)) {
1223 				rs->ti->error = "Only one 'raid10_format' argument pair allowed";
1224 				return -EINVAL;
1225 			}
1226 			if (!rt_is_raid10(rt)) {
1227 				rs->ti->error = "'raid10_format' is an invalid parameter for this RAID type";
1228 				return -EINVAL;
1229 			}
1230 			raid10_format = raid10_name_to_format(arg);
1231 			if (raid10_format < 0) {
1232 				rs->ti->error = "Invalid 'raid10_format' value given";
1233 				return raid10_format;
1234 			}
1235 			continue;
1236 		}
1237 
1238 		/* "journal_dev <dev>" */
1239 		if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_JOURNAL_DEV))) {
1240 			int r;
1241 			struct md_rdev *jdev;
1242 
1243 			if (test_and_set_bit(__CTR_FLAG_JOURNAL_DEV, &rs->ctr_flags)) {
1244 				rs->ti->error = "Only one raid4/5/6 set journaling device allowed";
1245 				return -EINVAL;
1246 			}
1247 			if (!rt_is_raid456(rt)) {
1248 				rs->ti->error = "'journal_dev' is an invalid parameter for this RAID type";
1249 				return -EINVAL;
1250 			}
1251 			r = dm_get_device(rs->ti, arg, dm_table_get_mode(rs->ti->table),
1252 					  &rs->journal_dev.dev);
1253 			if (r) {
1254 				rs->ti->error = "raid4/5/6 journal device lookup failure";
1255 				return r;
1256 			}
1257 			jdev = &rs->journal_dev.rdev;
1258 			md_rdev_init(jdev);
1259 			jdev->mddev = &rs->md;
1260 			jdev->bdev = rs->journal_dev.dev->bdev;
1261 			jdev->sectors = to_sector(i_size_read(jdev->bdev->bd_inode));
1262 			if (jdev->sectors < MIN_RAID456_JOURNAL_SPACE) {
1263 				rs->ti->error = "No space for raid4/5/6 journal";
1264 				return -ENOSPC;
1265 			}
1266 			rs->journal_dev.mode = R5C_JOURNAL_MODE_WRITE_THROUGH;
1267 			set_bit(Journal, &jdev->flags);
1268 			continue;
1269 		}
1270 
1271 		/* "journal_mode <mode>" ("journal_dev" mandatory!) */
1272 		if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_JOURNAL_MODE))) {
1273 			int r;
1274 
1275 			if (!test_bit(__CTR_FLAG_JOURNAL_DEV, &rs->ctr_flags)) {
1276 				rs->ti->error = "raid4/5/6 'journal_mode' is invalid without 'journal_dev'";
1277 				return -EINVAL;
1278 			}
1279 			if (test_and_set_bit(__CTR_FLAG_JOURNAL_MODE, &rs->ctr_flags)) {
1280 				rs->ti->error = "Only one raid4/5/6 'journal_mode' argument allowed";
1281 				return -EINVAL;
1282 			}
1283 			r = dm_raid_journal_mode_to_md(arg);
1284 			if (r < 0) {
1285 				rs->ti->error = "Invalid 'journal_mode' argument";
1286 				return r;
1287 			}
1288 			rs->journal_dev.mode = r;
1289 			continue;
1290 		}
1291 
1292 		/*
1293 		 * Parameters with number values from here on.
1294 		 */
1295 		if (kstrtoint(arg, 10, &value) < 0) {
1296 			rs->ti->error = "Bad numerical argument given in raid params";
1297 			return -EINVAL;
1298 		}
1299 
1300 		if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_REBUILD))) {
1301 			/*
1302 			 * "rebuild" is being passed in by userspace to provide
1303 			 * indexes of replaced devices and to set up additional
1304 			 * devices on raid level takeover.
1305 			 */
1306 			if (!__within_range(value, 0, rs->raid_disks - 1)) {
1307 				rs->ti->error = "Invalid rebuild index given";
1308 				return -EINVAL;
1309 			}
1310 
1311 			if (test_and_set_bit(value, (void *) rs->rebuild_disks)) {
1312 				rs->ti->error = "rebuild for this index already given";
1313 				return -EINVAL;
1314 			}
1315 
1316 			rd = rs->dev + value;
1317 			clear_bit(In_sync, &rd->rdev.flags);
1318 			clear_bit(Faulty, &rd->rdev.flags);
1319 			rd->rdev.recovery_offset = 0;
1320 			set_bit(__CTR_FLAG_REBUILD, &rs->ctr_flags);
1321 		} else if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_WRITE_MOSTLY))) {
1322 			if (!rt_is_raid1(rt)) {
1323 				rs->ti->error = "write_mostly option is only valid for RAID1";
1324 				return -EINVAL;
1325 			}
1326 
1327 			if (!__within_range(value, 0, rs->md.raid_disks - 1)) {
1328 				rs->ti->error = "Invalid write_mostly index given";
1329 				return -EINVAL;
1330 			}
1331 
1332 			write_mostly++;
1333 			set_bit(WriteMostly, &rs->dev[value].rdev.flags);
1334 			set_bit(__CTR_FLAG_WRITE_MOSTLY, &rs->ctr_flags);
1335 		} else if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_MAX_WRITE_BEHIND))) {
1336 			if (!rt_is_raid1(rt)) {
1337 				rs->ti->error = "max_write_behind option is only valid for RAID1";
1338 				return -EINVAL;
1339 			}
1340 
1341 			if (test_and_set_bit(__CTR_FLAG_MAX_WRITE_BEHIND, &rs->ctr_flags)) {
1342 				rs->ti->error = "Only one max_write_behind argument pair allowed";
1343 				return -EINVAL;
1344 			}
1345 
1346 			/*
1347 			 * In device-mapper, we specify things in sectors, but
1348 			 * MD records this value in kB
1349 			 */
1350 			if (value < 0 || value / 2 > COUNTER_MAX) {
1351 				rs->ti->error = "Max write-behind limit out of range";
1352 				return -EINVAL;
1353 			}
1354 
1355 			rs->md.bitmap_info.max_write_behind = value / 2;
1356 		} else if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_DAEMON_SLEEP))) {
1357 			if (test_and_set_bit(__CTR_FLAG_DAEMON_SLEEP, &rs->ctr_flags)) {
1358 				rs->ti->error = "Only one daemon_sleep argument pair allowed";
1359 				return -EINVAL;
1360 			}
1361 			if (value < 0) {
1362 				rs->ti->error = "daemon sleep period out of range";
1363 				return -EINVAL;
1364 			}
1365 			rs->md.bitmap_info.daemon_sleep = value;
1366 		} else if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_DATA_OFFSET))) {
1367 			/* Userspace passes new data_offset after having extended the the data image LV */
1368 			if (test_and_set_bit(__CTR_FLAG_DATA_OFFSET, &rs->ctr_flags)) {
1369 				rs->ti->error = "Only one data_offset argument pair allowed";
1370 				return -EINVAL;
1371 			}
1372 			/* Ensure sensible data offset */
1373 			if (value < 0 ||
1374 			    (value && (value < MIN_FREE_RESHAPE_SPACE || value % to_sector(PAGE_SIZE)))) {
1375 				rs->ti->error = "Bogus data_offset value";
1376 				return -EINVAL;
1377 			}
1378 			rs->data_offset = value;
1379 		} else if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_DELTA_DISKS))) {
1380 			/* Define the +/-# of disks to add to/remove from the given raid set */
1381 			if (test_and_set_bit(__CTR_FLAG_DELTA_DISKS, &rs->ctr_flags)) {
1382 				rs->ti->error = "Only one delta_disks argument pair allowed";
1383 				return -EINVAL;
1384 			}
1385 			/* Ensure MAX_RAID_DEVICES and raid type minimal_devs! */
1386 			if (!__within_range(abs(value), 1, MAX_RAID_DEVICES - rt->minimal_devs)) {
1387 				rs->ti->error = "Too many delta_disk requested";
1388 				return -EINVAL;
1389 			}
1390 
1391 			rs->delta_disks = value;
1392 		} else if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_STRIPE_CACHE))) {
1393 			if (test_and_set_bit(__CTR_FLAG_STRIPE_CACHE, &rs->ctr_flags)) {
1394 				rs->ti->error = "Only one stripe_cache argument pair allowed";
1395 				return -EINVAL;
1396 			}
1397 
1398 			if (!rt_is_raid456(rt)) {
1399 				rs->ti->error = "Inappropriate argument: stripe_cache";
1400 				return -EINVAL;
1401 			}
1402 
1403 			if (value < 0) {
1404 				rs->ti->error = "Bogus stripe cache entries value";
1405 				return -EINVAL;
1406 			}
1407 			rs->stripe_cache_entries = value;
1408 		} else if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_MIN_RECOVERY_RATE))) {
1409 			if (test_and_set_bit(__CTR_FLAG_MIN_RECOVERY_RATE, &rs->ctr_flags)) {
1410 				rs->ti->error = "Only one min_recovery_rate argument pair allowed";
1411 				return -EINVAL;
1412 			}
1413 
1414 			if (value < 0) {
1415 				rs->ti->error = "min_recovery_rate out of range";
1416 				return -EINVAL;
1417 			}
1418 			rs->md.sync_speed_min = value;
1419 		} else if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_MAX_RECOVERY_RATE))) {
1420 			if (test_and_set_bit(__CTR_FLAG_MAX_RECOVERY_RATE, &rs->ctr_flags)) {
1421 				rs->ti->error = "Only one max_recovery_rate argument pair allowed";
1422 				return -EINVAL;
1423 			}
1424 
1425 			if (value < 0) {
1426 				rs->ti->error = "max_recovery_rate out of range";
1427 				return -EINVAL;
1428 			}
1429 			rs->md.sync_speed_max = value;
1430 		} else if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_REGION_SIZE))) {
1431 			if (test_and_set_bit(__CTR_FLAG_REGION_SIZE, &rs->ctr_flags)) {
1432 				rs->ti->error = "Only one region_size argument pair allowed";
1433 				return -EINVAL;
1434 			}
1435 
1436 			region_size = value;
1437 			rs->requested_bitmap_chunk_sectors = value;
1438 		} else if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_RAID10_COPIES))) {
1439 			if (test_and_set_bit(__CTR_FLAG_RAID10_COPIES, &rs->ctr_flags)) {
1440 				rs->ti->error = "Only one raid10_copies argument pair allowed";
1441 				return -EINVAL;
1442 			}
1443 
1444 			if (!__within_range(value, 2, rs->md.raid_disks)) {
1445 				rs->ti->error = "Bad value for 'raid10_copies'";
1446 				return -EINVAL;
1447 			}
1448 
1449 			raid10_copies = value;
1450 		} else {
1451 			DMERR("Unable to parse RAID parameter: %s", key);
1452 			rs->ti->error = "Unable to parse RAID parameter";
1453 			return -EINVAL;
1454 		}
1455 	}
1456 
1457 	if (test_bit(__CTR_FLAG_SYNC, &rs->ctr_flags) &&
1458 	    test_bit(__CTR_FLAG_NOSYNC, &rs->ctr_flags)) {
1459 		rs->ti->error = "sync and nosync are mutually exclusive";
1460 		return -EINVAL;
1461 	}
1462 
1463 	if (test_bit(__CTR_FLAG_REBUILD, &rs->ctr_flags) &&
1464 	    (test_bit(__CTR_FLAG_SYNC, &rs->ctr_flags) ||
1465 	     test_bit(__CTR_FLAG_NOSYNC, &rs->ctr_flags))) {
1466 		rs->ti->error = "sync/nosync and rebuild are mutually exclusive";
1467 		return -EINVAL;
1468 	}
1469 
1470 	if (write_mostly >= rs->md.raid_disks) {
1471 		rs->ti->error = "Can't set all raid1 devices to write_mostly";
1472 		return -EINVAL;
1473 	}
1474 
1475 	if (rs->md.sync_speed_max &&
1476 	    rs->md.sync_speed_min > rs->md.sync_speed_max) {
1477 		rs->ti->error = "Bogus recovery rates";
1478 		return -EINVAL;
1479 	}
1480 
1481 	if (validate_region_size(rs, region_size))
1482 		return -EINVAL;
1483 
1484 	if (rs->md.chunk_sectors)
1485 		max_io_len = rs->md.chunk_sectors;
1486 	else
1487 		max_io_len = region_size;
1488 
1489 	if (dm_set_target_max_io_len(rs->ti, max_io_len))
1490 		return -EINVAL;
1491 
1492 	if (rt_is_raid10(rt)) {
1493 		if (raid10_copies > rs->md.raid_disks) {
1494 			rs->ti->error = "Not enough devices to satisfy specification";
1495 			return -EINVAL;
1496 		}
1497 
1498 		rs->md.new_layout = raid10_format_to_md_layout(rs, raid10_format, raid10_copies);
1499 		if (rs->md.new_layout < 0) {
1500 			rs->ti->error = "Error getting raid10 format";
1501 			return rs->md.new_layout;
1502 		}
1503 
1504 		rt = get_raid_type_by_ll(10, rs->md.new_layout);
1505 		if (!rt) {
1506 			rs->ti->error = "Failed to recognize new raid10 layout";
1507 			return -EINVAL;
1508 		}
1509 
1510 		if ((rt->algorithm == ALGORITHM_RAID10_DEFAULT ||
1511 		     rt->algorithm == ALGORITHM_RAID10_NEAR) &&
1512 		    test_bit(__CTR_FLAG_RAID10_USE_NEAR_SETS, &rs->ctr_flags)) {
1513 			rs->ti->error = "RAID10 format 'near' and 'raid10_use_near_sets' are incompatible";
1514 			return -EINVAL;
1515 		}
1516 	}
1517 
1518 	rs->raid10_copies = raid10_copies;
1519 
1520 	/* Assume there are no metadata devices until the drives are parsed */
1521 	rs->md.persistent = 0;
1522 	rs->md.external = 1;
1523 
1524 	/* Check, if any invalid ctr arguments have been passed in for the raid level */
1525 	return rs_check_for_valid_flags(rs);
1526 }
1527 
1528 /* Set raid4/5/6 cache size */
1529 static int rs_set_raid456_stripe_cache(struct raid_set *rs)
1530 {
1531 	int r;
1532 	struct r5conf *conf;
1533 	struct mddev *mddev = &rs->md;
1534 	uint32_t min_stripes = max(mddev->chunk_sectors, mddev->new_chunk_sectors) / 2;
1535 	uint32_t nr_stripes = rs->stripe_cache_entries;
1536 
1537 	if (!rt_is_raid456(rs->raid_type)) {
1538 		rs->ti->error = "Inappropriate raid level; cannot change stripe_cache size";
1539 		return -EINVAL;
1540 	}
1541 
1542 	if (nr_stripes < min_stripes) {
1543 		DMINFO("Adjusting requested %u stripe cache entries to %u to suit stripe size",
1544 		       nr_stripes, min_stripes);
1545 		nr_stripes = min_stripes;
1546 	}
1547 
1548 	conf = mddev->private;
1549 	if (!conf) {
1550 		rs->ti->error = "Cannot change stripe_cache size on inactive RAID set";
1551 		return -EINVAL;
1552 	}
1553 
1554 	/* Try setting number of stripes in raid456 stripe cache */
1555 	if (conf->min_nr_stripes != nr_stripes) {
1556 		r = raid5_set_cache_size(mddev, nr_stripes);
1557 		if (r) {
1558 			rs->ti->error = "Failed to set raid4/5/6 stripe cache size";
1559 			return r;
1560 		}
1561 
1562 		DMINFO("%u stripe cache entries", nr_stripes);
1563 	}
1564 
1565 	return 0;
1566 }
1567 
1568 /* Return # of data stripes as kept in mddev as of @rs (i.e. as of superblock) */
1569 static unsigned int mddev_data_stripes(struct raid_set *rs)
1570 {
1571 	return rs->md.raid_disks - rs->raid_type->parity_devs;
1572 }
1573 
1574 /* Return # of data stripes of @rs (i.e. as of ctr) */
1575 static unsigned int rs_data_stripes(struct raid_set *rs)
1576 {
1577 	return rs->raid_disks - rs->raid_type->parity_devs;
1578 }
1579 
1580 /*
1581  * Retrieve rdev->sectors from any valid raid device of @rs
1582  * to allow userpace to pass in arbitray "- -" device tupples.
1583  */
1584 static sector_t __rdev_sectors(struct raid_set *rs)
1585 {
1586 	int i;
1587 
1588 	for (i = 0; i < rs->md.raid_disks; i++) {
1589 		struct md_rdev *rdev = &rs->dev[i].rdev;
1590 
1591 		if (!test_bit(Journal, &rdev->flags) &&
1592 		    rdev->bdev && rdev->sectors)
1593 			return rdev->sectors;
1594 	}
1595 
1596 	return 0;
1597 }
1598 
1599 /* Check that calculated dev_sectors fits all component devices. */
1600 static int _check_data_dev_sectors(struct raid_set *rs)
1601 {
1602 	sector_t ds = ~0;
1603 	struct md_rdev *rdev;
1604 
1605 	rdev_for_each(rdev, &rs->md)
1606 		if (!test_bit(Journal, &rdev->flags) && rdev->bdev) {
1607 			ds = min(ds, to_sector(i_size_read(rdev->bdev->bd_inode)));
1608 			if (ds < rs->md.dev_sectors) {
1609 				rs->ti->error = "Component device(s) too small";
1610 				return -EINVAL;
1611 			}
1612 		}
1613 
1614 	return 0;
1615 }
1616 
1617 /* Calculate the sectors per device and per array used for @rs */
1618 static int rs_set_dev_and_array_sectors(struct raid_set *rs, bool use_mddev)
1619 {
1620 	int delta_disks;
1621 	unsigned int data_stripes;
1622 	struct mddev *mddev = &rs->md;
1623 	struct md_rdev *rdev;
1624 	sector_t array_sectors = rs->ti->len, dev_sectors = rs->ti->len;
1625 
1626 	if (use_mddev) {
1627 		delta_disks = mddev->delta_disks;
1628 		data_stripes = mddev_data_stripes(rs);
1629 	} else {
1630 		delta_disks = rs->delta_disks;
1631 		data_stripes = rs_data_stripes(rs);
1632 	}
1633 
1634 	/* Special raid1 case w/o delta_disks support (yet) */
1635 	if (rt_is_raid1(rs->raid_type))
1636 		;
1637 	else if (rt_is_raid10(rs->raid_type)) {
1638 		if (rs->raid10_copies < 2 ||
1639 		    delta_disks < 0) {
1640 			rs->ti->error = "Bogus raid10 data copies or delta disks";
1641 			return -EINVAL;
1642 		}
1643 
1644 		dev_sectors *= rs->raid10_copies;
1645 		if (sector_div(dev_sectors, data_stripes))
1646 			goto bad;
1647 
1648 		array_sectors = (data_stripes + delta_disks) * dev_sectors;
1649 		if (sector_div(array_sectors, rs->raid10_copies))
1650 			goto bad;
1651 
1652 	} else if (sector_div(dev_sectors, data_stripes))
1653 		goto bad;
1654 
1655 	else
1656 		/* Striped layouts */
1657 		array_sectors = (data_stripes + delta_disks) * dev_sectors;
1658 
1659 	rdev_for_each(rdev, mddev)
1660 		if (!test_bit(Journal, &rdev->flags))
1661 			rdev->sectors = dev_sectors;
1662 
1663 	mddev->array_sectors = array_sectors;
1664 	mddev->dev_sectors = dev_sectors;
1665 
1666 	return _check_data_dev_sectors(rs);
1667 bad:
1668 	rs->ti->error = "Target length not divisible by number of data devices";
1669 	return -EINVAL;
1670 }
1671 
1672 /* Setup recovery on @rs */
1673 static void __rs_setup_recovery(struct raid_set *rs, sector_t dev_sectors)
1674 {
1675 	/* raid0 does not recover */
1676 	if (rs_is_raid0(rs))
1677 		rs->md.recovery_cp = MaxSector;
1678 	/*
1679 	 * A raid6 set has to be recovered either
1680 	 * completely or for the grown part to
1681 	 * ensure proper parity and Q-Syndrome
1682 	 */
1683 	else if (rs_is_raid6(rs))
1684 		rs->md.recovery_cp = dev_sectors;
1685 	/*
1686 	 * Other raid set types may skip recovery
1687 	 * depending on the 'nosync' flag.
1688 	 */
1689 	else
1690 		rs->md.recovery_cp = test_bit(__CTR_FLAG_NOSYNC, &rs->ctr_flags)
1691 				     ? MaxSector : dev_sectors;
1692 }
1693 
1694 /* Setup recovery on @rs based on raid type, device size and 'nosync' flag */
1695 static void rs_setup_recovery(struct raid_set *rs, sector_t dev_sectors)
1696 {
1697 	if (!dev_sectors)
1698 		/* New raid set or 'sync' flag provided */
1699 		__rs_setup_recovery(rs, 0);
1700 	else if (dev_sectors == MaxSector)
1701 		/* Prevent recovery */
1702 		__rs_setup_recovery(rs, MaxSector);
1703 	else if (__rdev_sectors(rs) < dev_sectors)
1704 		/* Grown raid set */
1705 		__rs_setup_recovery(rs, __rdev_sectors(rs));
1706 	else
1707 		__rs_setup_recovery(rs, MaxSector);
1708 }
1709 
1710 static void do_table_event(struct work_struct *ws)
1711 {
1712 	struct raid_set *rs = container_of(ws, struct raid_set, md.event_work);
1713 
1714 	smp_rmb(); /* Make sure we access most actual mddev properties */
1715 	if (!rs_is_reshaping(rs)) {
1716 		if (rs_is_raid10(rs))
1717 			rs_set_rdev_sectors(rs);
1718 		rs_set_capacity(rs);
1719 	}
1720 	dm_table_event(rs->ti->table);
1721 }
1722 
1723 static int raid_is_congested(struct dm_target_callbacks *cb, int bits)
1724 {
1725 	struct raid_set *rs = container_of(cb, struct raid_set, callbacks);
1726 
1727 	return mddev_congested(&rs->md, bits);
1728 }
1729 
1730 /*
1731  * Make sure a valid takover (level switch) is being requested on @rs
1732  *
1733  * Conversions of raid sets from one MD personality to another
1734  * have to conform to restrictions which are enforced here.
1735  */
1736 static int rs_check_takeover(struct raid_set *rs)
1737 {
1738 	struct mddev *mddev = &rs->md;
1739 	unsigned int near_copies;
1740 
1741 	if (rs->md.degraded) {
1742 		rs->ti->error = "Can't takeover degraded raid set";
1743 		return -EPERM;
1744 	}
1745 
1746 	if (rs_is_reshaping(rs)) {
1747 		rs->ti->error = "Can't takeover reshaping raid set";
1748 		return -EPERM;
1749 	}
1750 
1751 	switch (mddev->level) {
1752 	case 0:
1753 		/* raid0 -> raid1/5 with one disk */
1754 		if ((mddev->new_level == 1 || mddev->new_level == 5) &&
1755 		    mddev->raid_disks == 1)
1756 			return 0;
1757 
1758 		/* raid0 -> raid10 */
1759 		if (mddev->new_level == 10 &&
1760 		    !(rs->raid_disks % mddev->raid_disks))
1761 			return 0;
1762 
1763 		/* raid0 with multiple disks -> raid4/5/6 */
1764 		if (__within_range(mddev->new_level, 4, 6) &&
1765 		    mddev->new_layout == ALGORITHM_PARITY_N &&
1766 		    mddev->raid_disks > 1)
1767 			return 0;
1768 
1769 		break;
1770 
1771 	case 10:
1772 		/* Can't takeover raid10_offset! */
1773 		if (__is_raid10_offset(mddev->layout))
1774 			break;
1775 
1776 		near_copies = __raid10_near_copies(mddev->layout);
1777 
1778 		/* raid10* -> raid0 */
1779 		if (mddev->new_level == 0) {
1780 			/* Can takeover raid10_near with raid disks divisable by data copies! */
1781 			if (near_copies > 1 &&
1782 			    !(mddev->raid_disks % near_copies)) {
1783 				mddev->raid_disks /= near_copies;
1784 				mddev->delta_disks = mddev->raid_disks;
1785 				return 0;
1786 			}
1787 
1788 			/* Can takeover raid10_far */
1789 			if (near_copies == 1 &&
1790 			    __raid10_far_copies(mddev->layout) > 1)
1791 				return 0;
1792 
1793 			break;
1794 		}
1795 
1796 		/* raid10_{near,far} -> raid1 */
1797 		if (mddev->new_level == 1 &&
1798 		    max(near_copies, __raid10_far_copies(mddev->layout)) == mddev->raid_disks)
1799 			return 0;
1800 
1801 		/* raid10_{near,far} with 2 disks -> raid4/5 */
1802 		if (__within_range(mddev->new_level, 4, 5) &&
1803 		    mddev->raid_disks == 2)
1804 			return 0;
1805 		break;
1806 
1807 	case 1:
1808 		/* raid1 with 2 disks -> raid4/5 */
1809 		if (__within_range(mddev->new_level, 4, 5) &&
1810 		    mddev->raid_disks == 2) {
1811 			mddev->degraded = 1;
1812 			return 0;
1813 		}
1814 
1815 		/* raid1 -> raid0 */
1816 		if (mddev->new_level == 0 &&
1817 		    mddev->raid_disks == 1)
1818 			return 0;
1819 
1820 		/* raid1 -> raid10 */
1821 		if (mddev->new_level == 10)
1822 			return 0;
1823 		break;
1824 
1825 	case 4:
1826 		/* raid4 -> raid0 */
1827 		if (mddev->new_level == 0)
1828 			return 0;
1829 
1830 		/* raid4 -> raid1/5 with 2 disks */
1831 		if ((mddev->new_level == 1 || mddev->new_level == 5) &&
1832 		    mddev->raid_disks == 2)
1833 			return 0;
1834 
1835 		/* raid4 -> raid5/6 with parity N */
1836 		if (__within_range(mddev->new_level, 5, 6) &&
1837 		    mddev->layout == ALGORITHM_PARITY_N)
1838 			return 0;
1839 		break;
1840 
1841 	case 5:
1842 		/* raid5 with parity N -> raid0 */
1843 		if (mddev->new_level == 0 &&
1844 		    mddev->layout == ALGORITHM_PARITY_N)
1845 			return 0;
1846 
1847 		/* raid5 with parity N -> raid4 */
1848 		if (mddev->new_level == 4 &&
1849 		    mddev->layout == ALGORITHM_PARITY_N)
1850 			return 0;
1851 
1852 		/* raid5 with 2 disks -> raid1/4/10 */
1853 		if ((mddev->new_level == 1 || mddev->new_level == 4 || mddev->new_level == 10) &&
1854 		    mddev->raid_disks == 2)
1855 			return 0;
1856 
1857 		/* raid5_* ->  raid6_*_6 with Q-Syndrome N (e.g. raid5_ra -> raid6_ra_6 */
1858 		if (mddev->new_level == 6 &&
1859 		    ((mddev->layout == ALGORITHM_PARITY_N && mddev->new_layout == ALGORITHM_PARITY_N) ||
1860 		      __within_range(mddev->new_layout, ALGORITHM_LEFT_ASYMMETRIC_6, ALGORITHM_RIGHT_SYMMETRIC_6)))
1861 			return 0;
1862 		break;
1863 
1864 	case 6:
1865 		/* raid6 with parity N -> raid0 */
1866 		if (mddev->new_level == 0 &&
1867 		    mddev->layout == ALGORITHM_PARITY_N)
1868 			return 0;
1869 
1870 		/* raid6 with parity N -> raid4 */
1871 		if (mddev->new_level == 4 &&
1872 		    mddev->layout == ALGORITHM_PARITY_N)
1873 			return 0;
1874 
1875 		/* raid6_*_n with Q-Syndrome N -> raid5_* */
1876 		if (mddev->new_level == 5 &&
1877 		    ((mddev->layout == ALGORITHM_PARITY_N && mddev->new_layout == ALGORITHM_PARITY_N) ||
1878 		     __within_range(mddev->new_layout, ALGORITHM_LEFT_ASYMMETRIC, ALGORITHM_RIGHT_SYMMETRIC)))
1879 			return 0;
1880 
1881 	default:
1882 		break;
1883 	}
1884 
1885 	rs->ti->error = "takeover not possible";
1886 	return -EINVAL;
1887 }
1888 
1889 /* True if @rs requested to be taken over */
1890 static bool rs_takeover_requested(struct raid_set *rs)
1891 {
1892 	return rs->md.new_level != rs->md.level;
1893 }
1894 
1895 /* True if @rs is requested to reshape by ctr */
1896 static bool rs_reshape_requested(struct raid_set *rs)
1897 {
1898 	bool change;
1899 	struct mddev *mddev = &rs->md;
1900 
1901 	if (rs_takeover_requested(rs))
1902 		return false;
1903 
1904 	if (rs_is_raid0(rs))
1905 		return false;
1906 
1907 	change = mddev->new_layout != mddev->layout ||
1908 		 mddev->new_chunk_sectors != mddev->chunk_sectors ||
1909 		 rs->delta_disks;
1910 
1911 	/* Historical case to support raid1 reshape without delta disks */
1912 	if (rs_is_raid1(rs)) {
1913 		if (rs->delta_disks)
1914 			return !!rs->delta_disks;
1915 
1916 		return !change &&
1917 		       mddev->raid_disks != rs->raid_disks;
1918 	}
1919 
1920 	if (rs_is_raid10(rs))
1921 		return change &&
1922 		       !__is_raid10_far(mddev->new_layout) &&
1923 		       rs->delta_disks >= 0;
1924 
1925 	return change;
1926 }
1927 
1928 /*  Features */
1929 #define	FEATURE_FLAG_SUPPORTS_V190	0x1 /* Supports extended superblock */
1930 
1931 /* State flags for sb->flags */
1932 #define	SB_FLAG_RESHAPE_ACTIVE		0x1
1933 #define	SB_FLAG_RESHAPE_BACKWARDS	0x2
1934 
1935 /*
1936  * This structure is never routinely used by userspace, unlike md superblocks.
1937  * Devices with this superblock should only ever be accessed via device-mapper.
1938  */
1939 #define DM_RAID_MAGIC 0x64526D44
1940 struct dm_raid_superblock {
1941 	__le32 magic;		/* "DmRd" */
1942 	__le32 compat_features;	/* Used to indicate compatible features (like 1.9.0 ondisk metadata extension) */
1943 
1944 	__le32 num_devices;	/* Number of devices in this raid set. (Max 64) */
1945 	__le32 array_position;	/* The position of this drive in the raid set */
1946 
1947 	__le64 events;		/* Incremented by md when superblock updated */
1948 	__le64 failed_devices;	/* Pre 1.9.0 part of bit field of devices to */
1949 				/* indicate failures (see extension below) */
1950 
1951 	/*
1952 	 * This offset tracks the progress of the repair or replacement of
1953 	 * an individual drive.
1954 	 */
1955 	__le64 disk_recovery_offset;
1956 
1957 	/*
1958 	 * This offset tracks the progress of the initial raid set
1959 	 * synchronisation/parity calculation.
1960 	 */
1961 	__le64 array_resync_offset;
1962 
1963 	/*
1964 	 * raid characteristics
1965 	 */
1966 	__le32 level;
1967 	__le32 layout;
1968 	__le32 stripe_sectors;
1969 
1970 	/********************************************************************
1971 	 * BELOW FOLLOW V1.9.0 EXTENSIONS TO THE PRISTINE SUPERBLOCK FORMAT!!!
1972 	 *
1973 	 * FEATURE_FLAG_SUPPORTS_V190 in the compat_features member indicates that those exist
1974 	 */
1975 
1976 	__le32 flags; /* Flags defining array states for reshaping */
1977 
1978 	/*
1979 	 * This offset tracks the progress of a raid
1980 	 * set reshape in order to be able to restart it
1981 	 */
1982 	__le64 reshape_position;
1983 
1984 	/*
1985 	 * These define the properties of the array in case of an interrupted reshape
1986 	 */
1987 	__le32 new_level;
1988 	__le32 new_layout;
1989 	__le32 new_stripe_sectors;
1990 	__le32 delta_disks;
1991 
1992 	__le64 array_sectors; /* Array size in sectors */
1993 
1994 	/*
1995 	 * Sector offsets to data on devices (reshaping).
1996 	 * Needed to support out of place reshaping, thus
1997 	 * not writing over any stripes whilst converting
1998 	 * them from old to new layout
1999 	 */
2000 	__le64 data_offset;
2001 	__le64 new_data_offset;
2002 
2003 	__le64 sectors; /* Used device size in sectors */
2004 
2005 	/*
2006 	 * Additonal Bit field of devices indicating failures to support
2007 	 * up to 256 devices with the 1.9.0 on-disk metadata format
2008 	 */
2009 	__le64 extended_failed_devices[DISKS_ARRAY_ELEMS - 1];
2010 
2011 	__le32 incompat_features;	/* Used to indicate any incompatible features */
2012 
2013 	/* Always set rest up to logical block size to 0 when writing (see get_metadata_device() below). */
2014 } __packed;
2015 
2016 /*
2017  * Check for reshape constraints on raid set @rs:
2018  *
2019  * - reshape function non-existent
2020  * - degraded set
2021  * - ongoing recovery
2022  * - ongoing reshape
2023  *
2024  * Returns 0 if none or -EPERM if given constraint
2025  * and error message reference in @errmsg
2026  */
2027 static int rs_check_reshape(struct raid_set *rs)
2028 {
2029 	struct mddev *mddev = &rs->md;
2030 
2031 	if (!mddev->pers || !mddev->pers->check_reshape)
2032 		rs->ti->error = "Reshape not supported";
2033 	else if (mddev->degraded)
2034 		rs->ti->error = "Can't reshape degraded raid set";
2035 	else if (rs_is_recovering(rs))
2036 		rs->ti->error = "Convert request on recovering raid set prohibited";
2037 	else if (rs_is_reshaping(rs))
2038 		rs->ti->error = "raid set already reshaping!";
2039 	else if (!(rs_is_raid1(rs) || rs_is_raid10(rs) || rs_is_raid456(rs)))
2040 		rs->ti->error = "Reshaping only supported for raid1/4/5/6/10";
2041 	else
2042 		return 0;
2043 
2044 	return -EPERM;
2045 }
2046 
2047 static int read_disk_sb(struct md_rdev *rdev, int size, bool force_reload)
2048 {
2049 	BUG_ON(!rdev->sb_page);
2050 
2051 	if (rdev->sb_loaded && !force_reload)
2052 		return 0;
2053 
2054 	rdev->sb_loaded = 0;
2055 
2056 	if (!sync_page_io(rdev, 0, size, rdev->sb_page, REQ_OP_READ, 0, true)) {
2057 		DMERR("Failed to read superblock of device at position %d",
2058 		      rdev->raid_disk);
2059 		md_error(rdev->mddev, rdev);
2060 		set_bit(Faulty, &rdev->flags);
2061 		return -EIO;
2062 	}
2063 
2064 	rdev->sb_loaded = 1;
2065 
2066 	return 0;
2067 }
2068 
2069 static void sb_retrieve_failed_devices(struct dm_raid_superblock *sb, uint64_t *failed_devices)
2070 {
2071 	failed_devices[0] = le64_to_cpu(sb->failed_devices);
2072 	memset(failed_devices + 1, 0, sizeof(sb->extended_failed_devices));
2073 
2074 	if (le32_to_cpu(sb->compat_features) & FEATURE_FLAG_SUPPORTS_V190) {
2075 		int i = ARRAY_SIZE(sb->extended_failed_devices);
2076 
2077 		while (i--)
2078 			failed_devices[i+1] = le64_to_cpu(sb->extended_failed_devices[i]);
2079 	}
2080 }
2081 
2082 static void sb_update_failed_devices(struct dm_raid_superblock *sb, uint64_t *failed_devices)
2083 {
2084 	int i = ARRAY_SIZE(sb->extended_failed_devices);
2085 
2086 	sb->failed_devices = cpu_to_le64(failed_devices[0]);
2087 	while (i--)
2088 		sb->extended_failed_devices[i] = cpu_to_le64(failed_devices[i+1]);
2089 }
2090 
2091 /*
2092  * Synchronize the superblock members with the raid set properties
2093  *
2094  * All superblock data is little endian.
2095  */
2096 static void super_sync(struct mddev *mddev, struct md_rdev *rdev)
2097 {
2098 	bool update_failed_devices = false;
2099 	unsigned int i;
2100 	uint64_t failed_devices[DISKS_ARRAY_ELEMS];
2101 	struct dm_raid_superblock *sb;
2102 	struct raid_set *rs = container_of(mddev, struct raid_set, md);
2103 
2104 	/* No metadata device, no superblock */
2105 	if (!rdev->meta_bdev)
2106 		return;
2107 
2108 	BUG_ON(!rdev->sb_page);
2109 
2110 	sb = page_address(rdev->sb_page);
2111 
2112 	sb_retrieve_failed_devices(sb, failed_devices);
2113 
2114 	for (i = 0; i < rs->raid_disks; i++)
2115 		if (!rs->dev[i].data_dev || test_bit(Faulty, &rs->dev[i].rdev.flags)) {
2116 			update_failed_devices = true;
2117 			set_bit(i, (void *) failed_devices);
2118 		}
2119 
2120 	if (update_failed_devices)
2121 		sb_update_failed_devices(sb, failed_devices);
2122 
2123 	sb->magic = cpu_to_le32(DM_RAID_MAGIC);
2124 	sb->compat_features = cpu_to_le32(FEATURE_FLAG_SUPPORTS_V190);
2125 
2126 	sb->num_devices = cpu_to_le32(mddev->raid_disks);
2127 	sb->array_position = cpu_to_le32(rdev->raid_disk);
2128 
2129 	sb->events = cpu_to_le64(mddev->events);
2130 
2131 	sb->disk_recovery_offset = cpu_to_le64(rdev->recovery_offset);
2132 	sb->array_resync_offset = cpu_to_le64(mddev->recovery_cp);
2133 
2134 	sb->level = cpu_to_le32(mddev->level);
2135 	sb->layout = cpu_to_le32(mddev->layout);
2136 	sb->stripe_sectors = cpu_to_le32(mddev->chunk_sectors);
2137 
2138 	/********************************************************************
2139 	 * BELOW FOLLOW V1.9.0 EXTENSIONS TO THE PRISTINE SUPERBLOCK FORMAT!!!
2140 	 *
2141 	 * FEATURE_FLAG_SUPPORTS_V190 in the compat_features member indicates that those exist
2142 	 */
2143 	sb->new_level = cpu_to_le32(mddev->new_level);
2144 	sb->new_layout = cpu_to_le32(mddev->new_layout);
2145 	sb->new_stripe_sectors = cpu_to_le32(mddev->new_chunk_sectors);
2146 
2147 	sb->delta_disks = cpu_to_le32(mddev->delta_disks);
2148 
2149 	smp_rmb(); /* Make sure we access most recent reshape position */
2150 	sb->reshape_position = cpu_to_le64(mddev->reshape_position);
2151 	if (le64_to_cpu(sb->reshape_position) != MaxSector) {
2152 		/* Flag ongoing reshape */
2153 		sb->flags |= cpu_to_le32(SB_FLAG_RESHAPE_ACTIVE);
2154 
2155 		if (mddev->delta_disks < 0 || mddev->reshape_backwards)
2156 			sb->flags |= cpu_to_le32(SB_FLAG_RESHAPE_BACKWARDS);
2157 	} else {
2158 		/* Clear reshape flags */
2159 		sb->flags &= ~(cpu_to_le32(SB_FLAG_RESHAPE_ACTIVE|SB_FLAG_RESHAPE_BACKWARDS));
2160 	}
2161 
2162 	sb->array_sectors = cpu_to_le64(mddev->array_sectors);
2163 	sb->data_offset = cpu_to_le64(rdev->data_offset);
2164 	sb->new_data_offset = cpu_to_le64(rdev->new_data_offset);
2165 	sb->sectors = cpu_to_le64(rdev->sectors);
2166 	sb->incompat_features = cpu_to_le32(0);
2167 
2168 	/* Zero out the rest of the payload after the size of the superblock */
2169 	memset(sb + 1, 0, rdev->sb_size - sizeof(*sb));
2170 }
2171 
2172 /*
2173  * super_load
2174  *
2175  * This function creates a superblock if one is not found on the device
2176  * and will decide which superblock to use if there's a choice.
2177  *
2178  * Return: 1 if use rdev, 0 if use refdev, -Exxx otherwise
2179  */
2180 static int super_load(struct md_rdev *rdev, struct md_rdev *refdev)
2181 {
2182 	int r;
2183 	struct dm_raid_superblock *sb;
2184 	struct dm_raid_superblock *refsb;
2185 	uint64_t events_sb, events_refsb;
2186 
2187 	r = read_disk_sb(rdev, rdev->sb_size, false);
2188 	if (r)
2189 		return r;
2190 
2191 	sb = page_address(rdev->sb_page);
2192 
2193 	/*
2194 	 * Two cases that we want to write new superblocks and rebuild:
2195 	 * 1) New device (no matching magic number)
2196 	 * 2) Device specified for rebuild (!In_sync w/ offset == 0)
2197 	 */
2198 	if ((sb->magic != cpu_to_le32(DM_RAID_MAGIC)) ||
2199 	    (!test_bit(In_sync, &rdev->flags) && !rdev->recovery_offset)) {
2200 		super_sync(rdev->mddev, rdev);
2201 
2202 		set_bit(FirstUse, &rdev->flags);
2203 		sb->compat_features = cpu_to_le32(FEATURE_FLAG_SUPPORTS_V190);
2204 
2205 		/* Force writing of superblocks to disk */
2206 		set_bit(MD_SB_CHANGE_DEVS, &rdev->mddev->sb_flags);
2207 
2208 		/* Any superblock is better than none, choose that if given */
2209 		return refdev ? 0 : 1;
2210 	}
2211 
2212 	if (!refdev)
2213 		return 1;
2214 
2215 	events_sb = le64_to_cpu(sb->events);
2216 
2217 	refsb = page_address(refdev->sb_page);
2218 	events_refsb = le64_to_cpu(refsb->events);
2219 
2220 	return (events_sb > events_refsb) ? 1 : 0;
2221 }
2222 
2223 static int super_init_validation(struct raid_set *rs, struct md_rdev *rdev)
2224 {
2225 	int role;
2226 	unsigned int d;
2227 	struct mddev *mddev = &rs->md;
2228 	uint64_t events_sb;
2229 	uint64_t failed_devices[DISKS_ARRAY_ELEMS];
2230 	struct dm_raid_superblock *sb;
2231 	uint32_t new_devs = 0, rebuild_and_new = 0, rebuilds = 0;
2232 	struct md_rdev *r;
2233 	struct dm_raid_superblock *sb2;
2234 
2235 	sb = page_address(rdev->sb_page);
2236 	events_sb = le64_to_cpu(sb->events);
2237 
2238 	/*
2239 	 * Initialise to 1 if this is a new superblock.
2240 	 */
2241 	mddev->events = events_sb ? : 1;
2242 
2243 	mddev->reshape_position = MaxSector;
2244 
2245 	mddev->raid_disks = le32_to_cpu(sb->num_devices);
2246 	mddev->level = le32_to_cpu(sb->level);
2247 	mddev->layout = le32_to_cpu(sb->layout);
2248 	mddev->chunk_sectors = le32_to_cpu(sb->stripe_sectors);
2249 
2250 	/*
2251 	 * Reshaping is supported, e.g. reshape_position is valid
2252 	 * in superblock and superblock content is authoritative.
2253 	 */
2254 	if (le32_to_cpu(sb->compat_features) & FEATURE_FLAG_SUPPORTS_V190) {
2255 		/* Superblock is authoritative wrt given raid set layout! */
2256 		mddev->new_level = le32_to_cpu(sb->new_level);
2257 		mddev->new_layout = le32_to_cpu(sb->new_layout);
2258 		mddev->new_chunk_sectors = le32_to_cpu(sb->new_stripe_sectors);
2259 		mddev->delta_disks = le32_to_cpu(sb->delta_disks);
2260 		mddev->array_sectors = le64_to_cpu(sb->array_sectors);
2261 
2262 		/* raid was reshaping and got interrupted */
2263 		if (le32_to_cpu(sb->flags) & SB_FLAG_RESHAPE_ACTIVE) {
2264 			if (test_bit(__CTR_FLAG_DELTA_DISKS, &rs->ctr_flags)) {
2265 				DMERR("Reshape requested but raid set is still reshaping");
2266 				return -EINVAL;
2267 			}
2268 
2269 			if (mddev->delta_disks < 0 ||
2270 			    (!mddev->delta_disks && (le32_to_cpu(sb->flags) & SB_FLAG_RESHAPE_BACKWARDS)))
2271 				mddev->reshape_backwards = 1;
2272 			else
2273 				mddev->reshape_backwards = 0;
2274 
2275 			mddev->reshape_position = le64_to_cpu(sb->reshape_position);
2276 			rs->raid_type = get_raid_type_by_ll(mddev->level, mddev->layout);
2277 		}
2278 
2279 	} else {
2280 		/*
2281 		 * No takeover/reshaping, because we don't have the extended v1.9.0 metadata
2282 		 */
2283 		struct raid_type *rt_cur = get_raid_type_by_ll(mddev->level, mddev->layout);
2284 		struct raid_type *rt_new = get_raid_type_by_ll(mddev->new_level, mddev->new_layout);
2285 
2286 		if (rs_takeover_requested(rs)) {
2287 			if (rt_cur && rt_new)
2288 				DMERR("Takeover raid sets from %s to %s not yet supported by metadata. (raid level change)",
2289 				      rt_cur->name, rt_new->name);
2290 			else
2291 				DMERR("Takeover raid sets not yet supported by metadata. (raid level change)");
2292 			return -EINVAL;
2293 		} else if (rs_reshape_requested(rs)) {
2294 			DMERR("Reshaping raid sets not yet supported by metadata. (raid layout change keeping level)");
2295 			if (mddev->layout != mddev->new_layout) {
2296 				if (rt_cur && rt_new)
2297 					DMERR("	 current layout %s vs new layout %s",
2298 					      rt_cur->name, rt_new->name);
2299 				else
2300 					DMERR("	 current layout 0x%X vs new layout 0x%X",
2301 					      le32_to_cpu(sb->layout), mddev->new_layout);
2302 			}
2303 			if (mddev->chunk_sectors != mddev->new_chunk_sectors)
2304 				DMERR("	 current stripe sectors %u vs new stripe sectors %u",
2305 				      mddev->chunk_sectors, mddev->new_chunk_sectors);
2306 			if (rs->delta_disks)
2307 				DMERR("	 current %u disks vs new %u disks",
2308 				      mddev->raid_disks, mddev->raid_disks + rs->delta_disks);
2309 			if (rs_is_raid10(rs)) {
2310 				DMERR("	 Old layout: %s w/ %u copies",
2311 				      raid10_md_layout_to_format(mddev->layout),
2312 				      raid10_md_layout_to_copies(mddev->layout));
2313 				DMERR("	 New layout: %s w/ %u copies",
2314 				      raid10_md_layout_to_format(mddev->new_layout),
2315 				      raid10_md_layout_to_copies(mddev->new_layout));
2316 			}
2317 			return -EINVAL;
2318 		}
2319 
2320 		DMINFO("Discovered old metadata format; upgrading to extended metadata format");
2321 	}
2322 
2323 	if (!test_bit(__CTR_FLAG_NOSYNC, &rs->ctr_flags))
2324 		mddev->recovery_cp = le64_to_cpu(sb->array_resync_offset);
2325 
2326 	/*
2327 	 * During load, we set FirstUse if a new superblock was written.
2328 	 * There are two reasons we might not have a superblock:
2329 	 * 1) The raid set is brand new - in which case, all of the
2330 	 *    devices must have their In_sync bit set.	Also,
2331 	 *    recovery_cp must be 0, unless forced.
2332 	 * 2) This is a new device being added to an old raid set
2333 	 *    and the new device needs to be rebuilt - in which
2334 	 *    case the In_sync bit will /not/ be set and
2335 	 *    recovery_cp must be MaxSector.
2336 	 * 3) This is/are a new device(s) being added to an old
2337 	 *    raid set during takeover to a higher raid level
2338 	 *    to provide capacity for redundancy or during reshape
2339 	 *    to add capacity to grow the raid set.
2340 	 */
2341 	d = 0;
2342 	rdev_for_each(r, mddev) {
2343 		if (test_bit(Journal, &rdev->flags))
2344 			continue;
2345 
2346 		if (test_bit(FirstUse, &r->flags))
2347 			new_devs++;
2348 
2349 		if (!test_bit(In_sync, &r->flags)) {
2350 			DMINFO("Device %d specified for rebuild; clearing superblock",
2351 				r->raid_disk);
2352 			rebuilds++;
2353 
2354 			if (test_bit(FirstUse, &r->flags))
2355 				rebuild_and_new++;
2356 		}
2357 
2358 		d++;
2359 	}
2360 
2361 	if (new_devs == rs->raid_disks || !rebuilds) {
2362 		/* Replace a broken device */
2363 		if (new_devs == 1 && !rs->delta_disks)
2364 			;
2365 		if (new_devs == rs->raid_disks) {
2366 			DMINFO("Superblocks created for new raid set");
2367 			set_bit(MD_ARRAY_FIRST_USE, &mddev->flags);
2368 		} else if (new_devs != rebuilds &&
2369 			   new_devs != rs->delta_disks) {
2370 			DMERR("New device injected into existing raid set without "
2371 			      "'delta_disks' or 'rebuild' parameter specified");
2372 			return -EINVAL;
2373 		}
2374 	} else if (new_devs && new_devs != rebuilds) {
2375 		DMERR("%u 'rebuild' devices cannot be injected into"
2376 		      " a raid set with %u other first-time devices",
2377 		      rebuilds, new_devs);
2378 		return -EINVAL;
2379 	} else if (rebuilds) {
2380 		if (rebuild_and_new && rebuilds != rebuild_and_new) {
2381 			DMERR("new device%s provided without 'rebuild'",
2382 			      new_devs > 1 ? "s" : "");
2383 			return -EINVAL;
2384 		} else if (!test_bit(__CTR_FLAG_REBUILD, &rs->ctr_flags) && rs_is_recovering(rs)) {
2385 			DMERR("'rebuild' specified while raid set is not in-sync (recovery_cp=%llu)",
2386 			      (unsigned long long) mddev->recovery_cp);
2387 			return -EINVAL;
2388 		} else if (rs_is_reshaping(rs)) {
2389 			DMERR("'rebuild' specified while raid set is being reshaped (reshape_position=%llu)",
2390 			      (unsigned long long) mddev->reshape_position);
2391 			return -EINVAL;
2392 		}
2393 	}
2394 
2395 	/*
2396 	 * Now we set the Faulty bit for those devices that are
2397 	 * recorded in the superblock as failed.
2398 	 */
2399 	sb_retrieve_failed_devices(sb, failed_devices);
2400 	rdev_for_each(r, mddev) {
2401 		if (test_bit(Journal, &rdev->flags) ||
2402 		    !r->sb_page)
2403 			continue;
2404 		sb2 = page_address(r->sb_page);
2405 		sb2->failed_devices = 0;
2406 		memset(sb2->extended_failed_devices, 0, sizeof(sb2->extended_failed_devices));
2407 
2408 		/*
2409 		 * Check for any device re-ordering.
2410 		 */
2411 		if (!test_bit(FirstUse, &r->flags) && (r->raid_disk >= 0)) {
2412 			role = le32_to_cpu(sb2->array_position);
2413 			if (role < 0)
2414 				continue;
2415 
2416 			if (role != r->raid_disk) {
2417 				if (rs_is_raid10(rs) && __is_raid10_near(mddev->layout)) {
2418 					if (mddev->raid_disks % __raid10_near_copies(mddev->layout) ||
2419 					    rs->raid_disks % rs->raid10_copies) {
2420 						rs->ti->error =
2421 							"Cannot change raid10 near set to odd # of devices!";
2422 						return -EINVAL;
2423 					}
2424 
2425 					sb2->array_position = cpu_to_le32(r->raid_disk);
2426 
2427 				} else if (!(rs_is_raid10(rs) && rt_is_raid0(rs->raid_type)) &&
2428 					   !(rs_is_raid0(rs) && rt_is_raid10(rs->raid_type)) &&
2429 					   !rt_is_raid1(rs->raid_type)) {
2430 					rs->ti->error = "Cannot change device positions in raid set";
2431 					return -EINVAL;
2432 				}
2433 
2434 				DMINFO("raid device #%d now at position #%d", role, r->raid_disk);
2435 			}
2436 
2437 			/*
2438 			 * Partial recovery is performed on
2439 			 * returning failed devices.
2440 			 */
2441 			if (test_bit(role, (void *) failed_devices))
2442 				set_bit(Faulty, &r->flags);
2443 		}
2444 	}
2445 
2446 	return 0;
2447 }
2448 
2449 static int super_validate(struct raid_set *rs, struct md_rdev *rdev)
2450 {
2451 	struct mddev *mddev = &rs->md;
2452 	struct dm_raid_superblock *sb;
2453 
2454 	if (rs_is_raid0(rs) || !rdev->sb_page || rdev->raid_disk < 0)
2455 		return 0;
2456 
2457 	sb = page_address(rdev->sb_page);
2458 
2459 	/*
2460 	 * If mddev->events is not set, we know we have not yet initialized
2461 	 * the array.
2462 	 */
2463 	if (!mddev->events && super_init_validation(rs, rdev))
2464 		return -EINVAL;
2465 
2466 	if (le32_to_cpu(sb->compat_features) &&
2467 	    le32_to_cpu(sb->compat_features) != FEATURE_FLAG_SUPPORTS_V190) {
2468 		rs->ti->error = "Unable to assemble array: Unknown flag(s) in compatible feature flags";
2469 		return -EINVAL;
2470 	}
2471 
2472 	if (sb->incompat_features) {
2473 		rs->ti->error = "Unable to assemble array: No incompatible feature flags supported yet";
2474 		return -EINVAL;
2475 	}
2476 
2477 	/* Enable bitmap creation for RAID levels != 0 */
2478 	mddev->bitmap_info.offset = rt_is_raid0(rs->raid_type) ? 0 : to_sector(4096);
2479 	mddev->bitmap_info.default_offset = mddev->bitmap_info.offset;
2480 
2481 	if (!test_and_clear_bit(FirstUse, &rdev->flags)) {
2482 		/*
2483 		 * Retrieve rdev size stored in superblock to be prepared for shrink.
2484 		 * Check extended superblock members are present otherwise the size
2485 		 * will not be set!
2486 		 */
2487 		if (le32_to_cpu(sb->compat_features) & FEATURE_FLAG_SUPPORTS_V190)
2488 			rdev->sectors = le64_to_cpu(sb->sectors);
2489 
2490 		rdev->recovery_offset = le64_to_cpu(sb->disk_recovery_offset);
2491 		if (rdev->recovery_offset == MaxSector)
2492 			set_bit(In_sync, &rdev->flags);
2493 		/*
2494 		 * If no reshape in progress -> we're recovering single
2495 		 * disk(s) and have to set the device(s) to out-of-sync
2496 		 */
2497 		else if (!rs_is_reshaping(rs))
2498 			clear_bit(In_sync, &rdev->flags); /* Mandatory for recovery */
2499 	}
2500 
2501 	/*
2502 	 * If a device comes back, set it as not In_sync and no longer faulty.
2503 	 */
2504 	if (test_and_clear_bit(Faulty, &rdev->flags)) {
2505 		rdev->recovery_offset = 0;
2506 		clear_bit(In_sync, &rdev->flags);
2507 		rdev->saved_raid_disk = rdev->raid_disk;
2508 	}
2509 
2510 	/* Reshape support -> restore repective data offsets */
2511 	rdev->data_offset = le64_to_cpu(sb->data_offset);
2512 	rdev->new_data_offset = le64_to_cpu(sb->new_data_offset);
2513 
2514 	return 0;
2515 }
2516 
2517 /*
2518  * Analyse superblocks and select the freshest.
2519  */
2520 static int analyse_superblocks(struct dm_target *ti, struct raid_set *rs)
2521 {
2522 	int r;
2523 	struct md_rdev *rdev, *freshest;
2524 	struct mddev *mddev = &rs->md;
2525 
2526 	freshest = NULL;
2527 	rdev_for_each(rdev, mddev) {
2528 		if (test_bit(Journal, &rdev->flags))
2529 			continue;
2530 
2531 		if (!rdev->meta_bdev)
2532 			continue;
2533 
2534 		/* Set superblock offset/size for metadata device. */
2535 		rdev->sb_start = 0;
2536 		rdev->sb_size = bdev_logical_block_size(rdev->meta_bdev);
2537 		if (rdev->sb_size < sizeof(struct dm_raid_superblock) || rdev->sb_size > PAGE_SIZE) {
2538 			DMERR("superblock size of a logical block is no longer valid");
2539 			return -EINVAL;
2540 		}
2541 
2542 		/*
2543 		 * Skipping super_load due to CTR_FLAG_SYNC will cause
2544 		 * the array to undergo initialization again as
2545 		 * though it were new.	This is the intended effect
2546 		 * of the "sync" directive.
2547 		 *
2548 		 * With reshaping capability added, we must ensure that
2549 		 * that the "sync" directive is disallowed during the reshape.
2550 		 */
2551 		if (test_bit(__CTR_FLAG_SYNC, &rs->ctr_flags))
2552 			continue;
2553 
2554 		r = super_load(rdev, freshest);
2555 
2556 		switch (r) {
2557 		case 1:
2558 			freshest = rdev;
2559 			break;
2560 		case 0:
2561 			break;
2562 		default:
2563 			/* This is a failure to read the superblock from the metadata device. */
2564 			/*
2565 			 * We have to keep any raid0 data/metadata device pairs or
2566 			 * the MD raid0 personality will fail to start the array.
2567 			 */
2568 			if (rs_is_raid0(rs))
2569 				continue;
2570 
2571 			/*
2572 			 * We keep the dm_devs to be able to emit the device tuple
2573 			 * properly on the table line in raid_status() (rather than
2574 			 * mistakenly acting as if '- -' got passed into the constructor).
2575 			 *
2576 			 * The rdev has to stay on the same_set list to allow for
2577 			 * the attempt to restore faulty devices on second resume.
2578 			 */
2579 			rdev->raid_disk = rdev->saved_raid_disk = -1;
2580 			break;
2581 		}
2582 	}
2583 
2584 	if (!freshest)
2585 		return 0;
2586 
2587 	/*
2588 	 * Validation of the freshest device provides the source of
2589 	 * validation for the remaining devices.
2590 	 */
2591 	rs->ti->error = "Unable to assemble array: Invalid superblocks";
2592 	if (super_validate(rs, freshest))
2593 		return -EINVAL;
2594 
2595 	if (validate_raid_redundancy(rs)) {
2596 		rs->ti->error = "Insufficient redundancy to activate array";
2597 		return -EINVAL;
2598 	}
2599 
2600 	rdev_for_each(rdev, mddev)
2601 		if (!test_bit(Journal, &rdev->flags) &&
2602 		    rdev != freshest &&
2603 		    super_validate(rs, rdev))
2604 			return -EINVAL;
2605 	return 0;
2606 }
2607 
2608 /*
2609  * Adjust data_offset and new_data_offset on all disk members of @rs
2610  * for out of place reshaping if requested by contructor
2611  *
2612  * We need free space at the beginning of each raid disk for forward
2613  * and at the end for backward reshapes which userspace has to provide
2614  * via remapping/reordering of space.
2615  */
2616 static int rs_adjust_data_offsets(struct raid_set *rs)
2617 {
2618 	sector_t data_offset = 0, new_data_offset = 0;
2619 	struct md_rdev *rdev;
2620 
2621 	/* Constructor did not request data offset change */
2622 	if (!test_bit(__CTR_FLAG_DATA_OFFSET, &rs->ctr_flags)) {
2623 		if (!rs_is_reshapable(rs))
2624 			goto out;
2625 
2626 		return 0;
2627 	}
2628 
2629 	/* HM FIXME: get In_Sync raid_dev? */
2630 	rdev = &rs->dev[0].rdev;
2631 
2632 	if (rs->delta_disks < 0) {
2633 		/*
2634 		 * Removing disks (reshaping backwards):
2635 		 *
2636 		 * - before reshape: data is at offset 0 and free space
2637 		 *		     is at end of each component LV
2638 		 *
2639 		 * - after reshape: data is at offset rs->data_offset != 0 on each component LV
2640 		 */
2641 		data_offset = 0;
2642 		new_data_offset = rs->data_offset;
2643 
2644 	} else if (rs->delta_disks > 0) {
2645 		/*
2646 		 * Adding disks (reshaping forwards):
2647 		 *
2648 		 * - before reshape: data is at offset rs->data_offset != 0 and
2649 		 *		     free space is at begin of each component LV
2650 		 *
2651 		 * - after reshape: data is at offset 0 on each component LV
2652 		 */
2653 		data_offset = rs->data_offset;
2654 		new_data_offset = 0;
2655 
2656 	} else {
2657 		/*
2658 		 * User space passes in 0 for data offset after having removed reshape space
2659 		 *
2660 		 * - or - (data offset != 0)
2661 		 *
2662 		 * Changing RAID layout or chunk size -> toggle offsets
2663 		 *
2664 		 * - before reshape: data is at offset rs->data_offset 0 and
2665 		 *		     free space is at end of each component LV
2666 		 *		     -or-
2667 		 *                   data is at offset rs->data_offset != 0 and
2668 		 *		     free space is at begin of each component LV
2669 		 *
2670 		 * - after reshape: data is at offset 0 if it was at offset != 0
2671 		 *                  or at offset != 0 if it was at offset 0
2672 		 *                  on each component LV
2673 		 *
2674 		 */
2675 		data_offset = rs->data_offset ? rdev->data_offset : 0;
2676 		new_data_offset = data_offset ? 0 : rs->data_offset;
2677 		set_bit(RT_FLAG_UPDATE_SBS, &rs->runtime_flags);
2678 	}
2679 
2680 	/*
2681 	 * Make sure we got a minimum amount of free sectors per device
2682 	 */
2683 	if (rs->data_offset &&
2684 	    to_sector(i_size_read(rdev->bdev->bd_inode)) - rs->md.dev_sectors < MIN_FREE_RESHAPE_SPACE) {
2685 		rs->ti->error = data_offset ? "No space for forward reshape" :
2686 					      "No space for backward reshape";
2687 		return -ENOSPC;
2688 	}
2689 out:
2690 	/*
2691 	 * Raise recovery_cp in case data_offset != 0 to
2692 	 * avoid false recovery positives in the constructor.
2693 	 */
2694 	if (rs->md.recovery_cp < rs->md.dev_sectors)
2695 		rs->md.recovery_cp += rs->dev[0].rdev.data_offset;
2696 
2697 	/* Adjust data offsets on all rdevs but on any raid4/5/6 journal device */
2698 	rdev_for_each(rdev, &rs->md) {
2699 		if (!test_bit(Journal, &rdev->flags)) {
2700 			rdev->data_offset = data_offset;
2701 			rdev->new_data_offset = new_data_offset;
2702 		}
2703 	}
2704 
2705 	return 0;
2706 }
2707 
2708 /* Userpace reordered disks -> adjust raid_disk indexes in @rs */
2709 static void __reorder_raid_disk_indexes(struct raid_set *rs)
2710 {
2711 	int i = 0;
2712 	struct md_rdev *rdev;
2713 
2714 	rdev_for_each(rdev, &rs->md) {
2715 		if (!test_bit(Journal, &rdev->flags)) {
2716 			rdev->raid_disk = i++;
2717 			rdev->saved_raid_disk = rdev->new_raid_disk = -1;
2718 		}
2719 	}
2720 }
2721 
2722 /*
2723  * Setup @rs for takeover by a different raid level
2724  */
2725 static int rs_setup_takeover(struct raid_set *rs)
2726 {
2727 	struct mddev *mddev = &rs->md;
2728 	struct md_rdev *rdev;
2729 	unsigned int d = mddev->raid_disks = rs->raid_disks;
2730 	sector_t new_data_offset = rs->dev[0].rdev.data_offset ? 0 : rs->data_offset;
2731 
2732 	if (rt_is_raid10(rs->raid_type)) {
2733 		if (rs_is_raid0(rs)) {
2734 			/* Userpace reordered disks -> adjust raid_disk indexes */
2735 			__reorder_raid_disk_indexes(rs);
2736 
2737 			/* raid0 -> raid10_far layout */
2738 			mddev->layout = raid10_format_to_md_layout(rs, ALGORITHM_RAID10_FAR,
2739 								   rs->raid10_copies);
2740 		} else if (rs_is_raid1(rs))
2741 			/* raid1 -> raid10_near layout */
2742 			mddev->layout = raid10_format_to_md_layout(rs, ALGORITHM_RAID10_NEAR,
2743 								   rs->raid_disks);
2744 		else
2745 			return -EINVAL;
2746 
2747 	}
2748 
2749 	clear_bit(MD_ARRAY_FIRST_USE, &mddev->flags);
2750 	mddev->recovery_cp = MaxSector;
2751 
2752 	while (d--) {
2753 		rdev = &rs->dev[d].rdev;
2754 
2755 		if (test_bit(d, (void *) rs->rebuild_disks)) {
2756 			clear_bit(In_sync, &rdev->flags);
2757 			clear_bit(Faulty, &rdev->flags);
2758 			mddev->recovery_cp = rdev->recovery_offset = 0;
2759 			/* Bitmap has to be created when we do an "up" takeover */
2760 			set_bit(MD_ARRAY_FIRST_USE, &mddev->flags);
2761 		}
2762 
2763 		rdev->new_data_offset = new_data_offset;
2764 	}
2765 
2766 	return 0;
2767 }
2768 
2769 /* Prepare @rs for reshape */
2770 static int rs_prepare_reshape(struct raid_set *rs)
2771 {
2772 	bool reshape;
2773 	struct mddev *mddev = &rs->md;
2774 
2775 	if (rs_is_raid10(rs)) {
2776 		if (rs->raid_disks != mddev->raid_disks &&
2777 		    __is_raid10_near(mddev->layout) &&
2778 		    rs->raid10_copies &&
2779 		    rs->raid10_copies != __raid10_near_copies(mddev->layout)) {
2780 			/*
2781 			 * raid disk have to be multiple of data copies to allow this conversion,
2782 			 *
2783 			 * This is actually not a reshape it is a
2784 			 * rebuild of any additional mirrors per group
2785 			 */
2786 			if (rs->raid_disks % rs->raid10_copies) {
2787 				rs->ti->error = "Can't reshape raid10 mirror groups";
2788 				return -EINVAL;
2789 			}
2790 
2791 			/* Userpace reordered disks to add/remove mirrors -> adjust raid_disk indexes */
2792 			__reorder_raid_disk_indexes(rs);
2793 			mddev->layout = raid10_format_to_md_layout(rs, ALGORITHM_RAID10_NEAR,
2794 								   rs->raid10_copies);
2795 			mddev->new_layout = mddev->layout;
2796 			reshape = false;
2797 		} else
2798 			reshape = true;
2799 
2800 	} else if (rs_is_raid456(rs))
2801 		reshape = true;
2802 
2803 	else if (rs_is_raid1(rs)) {
2804 		if (rs->delta_disks) {
2805 			/* Process raid1 via delta_disks */
2806 			mddev->degraded = rs->delta_disks < 0 ? -rs->delta_disks : rs->delta_disks;
2807 			reshape = true;
2808 		} else {
2809 			/* Process raid1 without delta_disks */
2810 			mddev->raid_disks = rs->raid_disks;
2811 			reshape = false;
2812 		}
2813 	} else {
2814 		rs->ti->error = "Called with bogus raid type";
2815 		return -EINVAL;
2816 	}
2817 
2818 	if (reshape) {
2819 		set_bit(RT_FLAG_RESHAPE_RS, &rs->runtime_flags);
2820 		set_bit(RT_FLAG_UPDATE_SBS, &rs->runtime_flags);
2821 	} else if (mddev->raid_disks < rs->raid_disks)
2822 		/* Create new superblocks and bitmaps, if any new disks */
2823 		set_bit(RT_FLAG_UPDATE_SBS, &rs->runtime_flags);
2824 
2825 	return 0;
2826 }
2827 
2828 /* Get reshape sectors from data_offsets or raid set */
2829 static sector_t _get_reshape_sectors(struct raid_set *rs)
2830 {
2831 	struct md_rdev *rdev;
2832 	sector_t reshape_sectors = 0;
2833 
2834 	rdev_for_each(rdev, &rs->md)
2835 		if (!test_bit(Journal, &rdev->flags)) {
2836 			reshape_sectors = (rdev->data_offset > rdev->new_data_offset) ?
2837 					rdev->data_offset - rdev->new_data_offset :
2838 					rdev->new_data_offset - rdev->data_offset;
2839 			break;
2840 		}
2841 
2842 	return max(reshape_sectors, (sector_t) rs->data_offset);
2843 }
2844 
2845 /*
2846  *
2847  * - change raid layout
2848  * - change chunk size
2849  * - add disks
2850  * - remove disks
2851  */
2852 static int rs_setup_reshape(struct raid_set *rs)
2853 {
2854 	int r = 0;
2855 	unsigned int cur_raid_devs, d;
2856 	sector_t reshape_sectors = _get_reshape_sectors(rs);
2857 	struct mddev *mddev = &rs->md;
2858 	struct md_rdev *rdev;
2859 
2860 	mddev->delta_disks = rs->delta_disks;
2861 	cur_raid_devs = mddev->raid_disks;
2862 
2863 	/* Ignore impossible layout change whilst adding/removing disks */
2864 	if (mddev->delta_disks &&
2865 	    mddev->layout != mddev->new_layout) {
2866 		DMINFO("Ignoring invalid layout change with delta_disks=%d", rs->delta_disks);
2867 		mddev->new_layout = mddev->layout;
2868 	}
2869 
2870 	/*
2871 	 * Adjust array size:
2872 	 *
2873 	 * - in case of adding disk(s), array size has
2874 	 *   to grow after the disk adding reshape,
2875 	 *   which'll hapen in the event handler;
2876 	 *   reshape will happen forward, so space has to
2877 	 *   be available at the beginning of each disk
2878 	 *
2879 	 * - in case of removing disk(s), array size
2880 	 *   has to shrink before starting the reshape,
2881 	 *   which'll happen here;
2882 	 *   reshape will happen backward, so space has to
2883 	 *   be available at the end of each disk
2884 	 *
2885 	 * - data_offset and new_data_offset are
2886 	 *   adjusted for aforementioned out of place
2887 	 *   reshaping based on userspace passing in
2888 	 *   the "data_offset <sectors>" key/value
2889 	 *   pair via the constructor
2890 	 */
2891 
2892 	/* Add disk(s) */
2893 	if (rs->delta_disks > 0) {
2894 		/* Prepare disks for check in raid4/5/6/10 {check|start}_reshape */
2895 		for (d = cur_raid_devs; d < rs->raid_disks; d++) {
2896 			rdev = &rs->dev[d].rdev;
2897 			clear_bit(In_sync, &rdev->flags);
2898 
2899 			/*
2900 			 * save_raid_disk needs to be -1, or recovery_offset will be set to 0
2901 			 * by md, which'll store that erroneously in the superblock on reshape
2902 			 */
2903 			rdev->saved_raid_disk = -1;
2904 			rdev->raid_disk = d;
2905 
2906 			rdev->sectors = mddev->dev_sectors;
2907 			rdev->recovery_offset = rs_is_raid1(rs) ? 0 : MaxSector;
2908 		}
2909 
2910 		mddev->reshape_backwards = 0; /* adding disk(s) -> forward reshape */
2911 
2912 	/* Remove disk(s) */
2913 	} else if (rs->delta_disks < 0) {
2914 		r = rs_set_dev_and_array_sectors(rs, true);
2915 		mddev->reshape_backwards = 1; /* removing disk(s) -> backward reshape */
2916 
2917 	/* Change layout and/or chunk size */
2918 	} else {
2919 		/*
2920 		 * Reshape layout (e.g. raid5_ls -> raid5_n) and/or chunk size:
2921 		 *
2922 		 * keeping number of disks and do layout change ->
2923 		 *
2924 		 * toggle reshape_backward depending on data_offset:
2925 		 *
2926 		 * - free space upfront -> reshape forward
2927 		 *
2928 		 * - free space at the end -> reshape backward
2929 		 *
2930 		 *
2931 		 * This utilizes free reshape space avoiding the need
2932 		 * for userspace to move (parts of) LV segments in
2933 		 * case of layout/chunksize change  (for disk
2934 		 * adding/removing reshape space has to be at
2935 		 * the proper address (see above with delta_disks):
2936 		 *
2937 		 * add disk(s)   -> begin
2938 		 * remove disk(s)-> end
2939 		 */
2940 		mddev->reshape_backwards = rs->dev[0].rdev.data_offset ? 0 : 1;
2941 	}
2942 
2943 	/*
2944 	 * Adjust device size for forward reshape
2945 	 * because md_finish_reshape() reduces it.
2946 	 */
2947 	if (!mddev->reshape_backwards)
2948 		rdev_for_each(rdev, &rs->md)
2949 			if (!test_bit(Journal, &rdev->flags))
2950 				rdev->sectors += reshape_sectors;
2951 
2952 	return r;
2953 }
2954 
2955 /*
2956  * Enable/disable discard support on RAID set depending on
2957  * RAID level and discard properties of underlying RAID members.
2958  */
2959 static void configure_discard_support(struct raid_set *rs)
2960 {
2961 	int i;
2962 	bool raid456;
2963 	struct dm_target *ti = rs->ti;
2964 
2965 	/*
2966 	 * XXX: RAID level 4,5,6 require zeroing for safety.
2967 	 */
2968 	raid456 = rs_is_raid456(rs);
2969 
2970 	for (i = 0; i < rs->raid_disks; i++) {
2971 		struct request_queue *q;
2972 
2973 		if (!rs->dev[i].rdev.bdev)
2974 			continue;
2975 
2976 		q = bdev_get_queue(rs->dev[i].rdev.bdev);
2977 		if (!q || !blk_queue_discard(q))
2978 			return;
2979 
2980 		if (raid456) {
2981 			if (!devices_handle_discard_safely) {
2982 				DMERR("raid456 discard support disabled due to discard_zeroes_data uncertainty.");
2983 				DMERR("Set dm-raid.devices_handle_discard_safely=Y to override.");
2984 				return;
2985 			}
2986 		}
2987 	}
2988 
2989 	/*
2990 	 * RAID1 and RAID10 personalities require bio splitting,
2991 	 * RAID0/4/5/6 don't and process large discard bios properly.
2992 	 */
2993 	ti->split_discard_bios = !!(rs_is_raid1(rs) || rs_is_raid10(rs));
2994 	ti->num_discard_bios = 1;
2995 }
2996 
2997 /*
2998  * Construct a RAID0/1/10/4/5/6 mapping:
2999  * Args:
3000  *	<raid_type> <#raid_params> <raid_params>{0,}	\
3001  *	<#raid_devs> [<meta_dev1> <dev1>]{1,}
3002  *
3003  * <raid_params> varies by <raid_type>.	 See 'parse_raid_params' for
3004  * details on possible <raid_params>.
3005  *
3006  * Userspace is free to initialize the metadata devices, hence the superblocks to
3007  * enforce recreation based on the passed in table parameters.
3008  *
3009  */
3010 static int raid_ctr(struct dm_target *ti, unsigned int argc, char **argv)
3011 {
3012 	int r;
3013 	bool resize = false;
3014 	struct raid_type *rt;
3015 	unsigned int num_raid_params, num_raid_devs;
3016 	sector_t calculated_dev_sectors, rdev_sectors, reshape_sectors;
3017 	struct raid_set *rs = NULL;
3018 	const char *arg;
3019 	struct rs_layout rs_layout;
3020 	struct dm_arg_set as = { argc, argv }, as_nrd;
3021 	struct dm_arg _args[] = {
3022 		{ 0, as.argc, "Cannot understand number of raid parameters" },
3023 		{ 1, 254, "Cannot understand number of raid devices parameters" }
3024 	};
3025 
3026 	/* Must have <raid_type> */
3027 	arg = dm_shift_arg(&as);
3028 	if (!arg) {
3029 		ti->error = "No arguments";
3030 		return -EINVAL;
3031 	}
3032 
3033 	rt = get_raid_type(arg);
3034 	if (!rt) {
3035 		ti->error = "Unrecognised raid_type";
3036 		return -EINVAL;
3037 	}
3038 
3039 	/* Must have <#raid_params> */
3040 	if (dm_read_arg_group(_args, &as, &num_raid_params, &ti->error))
3041 		return -EINVAL;
3042 
3043 	/* number of raid device tupples <meta_dev data_dev> */
3044 	as_nrd = as;
3045 	dm_consume_args(&as_nrd, num_raid_params);
3046 	_args[1].max = (as_nrd.argc - 1) / 2;
3047 	if (dm_read_arg(_args + 1, &as_nrd, &num_raid_devs, &ti->error))
3048 		return -EINVAL;
3049 
3050 	if (!__within_range(num_raid_devs, 1, MAX_RAID_DEVICES)) {
3051 		ti->error = "Invalid number of supplied raid devices";
3052 		return -EINVAL;
3053 	}
3054 
3055 	rs = raid_set_alloc(ti, rt, num_raid_devs);
3056 	if (IS_ERR(rs))
3057 		return PTR_ERR(rs);
3058 
3059 	r = parse_raid_params(rs, &as, num_raid_params);
3060 	if (r)
3061 		goto bad;
3062 
3063 	r = parse_dev_params(rs, &as);
3064 	if (r)
3065 		goto bad;
3066 
3067 	rs->md.sync_super = super_sync;
3068 
3069 	/*
3070 	 * Calculate ctr requested array and device sizes to allow
3071 	 * for superblock analysis needing device sizes defined.
3072 	 *
3073 	 * Any existing superblock will overwrite the array and device sizes
3074 	 */
3075 	r = rs_set_dev_and_array_sectors(rs, false);
3076 	if (r)
3077 		goto bad;
3078 
3079 	calculated_dev_sectors = rs->md.dev_sectors;
3080 
3081 	/*
3082 	 * Backup any new raid set level, layout, ...
3083 	 * requested to be able to compare to superblock
3084 	 * members for conversion decisions.
3085 	 */
3086 	rs_config_backup(rs, &rs_layout);
3087 
3088 	r = analyse_superblocks(ti, rs);
3089 	if (r)
3090 		goto bad;
3091 
3092 	rdev_sectors = __rdev_sectors(rs);
3093 	if (!rdev_sectors) {
3094 		ti->error = "Invalid rdev size";
3095 		r = -EINVAL;
3096 		goto bad;
3097 	}
3098 
3099 
3100 	reshape_sectors = _get_reshape_sectors(rs);
3101 	if (calculated_dev_sectors != rdev_sectors)
3102 		resize = calculated_dev_sectors != (reshape_sectors ? rdev_sectors - reshape_sectors : rdev_sectors);
3103 
3104 	INIT_WORK(&rs->md.event_work, do_table_event);
3105 	ti->private = rs;
3106 	ti->num_flush_bios = 1;
3107 
3108 	/* Restore any requested new layout for conversion decision */
3109 	rs_config_restore(rs, &rs_layout);
3110 
3111 	/*
3112 	 * Now that we have any superblock metadata available,
3113 	 * check for new, recovering, reshaping, to be taken over,
3114 	 * to be reshaped or an existing, unchanged raid set to
3115 	 * run in sequence.
3116 	 */
3117 	if (test_bit(MD_ARRAY_FIRST_USE, &rs->md.flags)) {
3118 		/* A new raid6 set has to be recovered to ensure proper parity and Q-Syndrome */
3119 		if (rs_is_raid6(rs) &&
3120 		    test_bit(__CTR_FLAG_NOSYNC, &rs->ctr_flags)) {
3121 			ti->error = "'nosync' not allowed for new raid6 set";
3122 			r = -EINVAL;
3123 			goto bad;
3124 		}
3125 		rs_setup_recovery(rs, 0);
3126 		set_bit(RT_FLAG_UPDATE_SBS, &rs->runtime_flags);
3127 		rs_set_new(rs);
3128 	} else if (rs_is_recovering(rs)) {
3129 		/* Rebuild particular devices */
3130 		if (test_bit(__CTR_FLAG_REBUILD, &rs->ctr_flags)) {
3131 			set_bit(RT_FLAG_UPDATE_SBS, &rs->runtime_flags);
3132 			rs_setup_recovery(rs, MaxSector);
3133 		}
3134 		/* A recovering raid set may be resized */
3135 		; /* skip setup rs */
3136 	} else if (rs_is_reshaping(rs)) {
3137 		/* Have to reject size change request during reshape */
3138 		if (resize) {
3139 			ti->error = "Can't resize a reshaping raid set";
3140 			r = -EPERM;
3141 			goto bad;
3142 		}
3143 		/* skip setup rs */
3144 	} else if (rs_takeover_requested(rs)) {
3145 		if (rs_is_reshaping(rs)) {
3146 			ti->error = "Can't takeover a reshaping raid set";
3147 			r = -EPERM;
3148 			goto bad;
3149 		}
3150 
3151 		/* We can't takeover a journaled raid4/5/6 */
3152 		if (test_bit(__CTR_FLAG_JOURNAL_DEV, &rs->ctr_flags)) {
3153 			ti->error = "Can't takeover a journaled raid4/5/6 set";
3154 			r = -EPERM;
3155 			goto bad;
3156 		}
3157 
3158 		/*
3159 		 * If a takeover is needed, userspace sets any additional
3160 		 * devices to rebuild and we can check for a valid request here.
3161 		 *
3162 		 * If acceptible, set the level to the new requested
3163 		 * one, prohibit requesting recovery, allow the raid
3164 		 * set to run and store superblocks during resume.
3165 		 */
3166 		r = rs_check_takeover(rs);
3167 		if (r)
3168 			goto bad;
3169 
3170 		r = rs_setup_takeover(rs);
3171 		if (r)
3172 			goto bad;
3173 
3174 		set_bit(RT_FLAG_UPDATE_SBS, &rs->runtime_flags);
3175 		/* Takeover ain't recovery, so disable recovery */
3176 		rs_setup_recovery(rs, MaxSector);
3177 		rs_set_new(rs);
3178 	} else if (rs_reshape_requested(rs)) {
3179 		/*
3180 		 * No need to check for 'ongoing' takeover here, because takeover
3181 		 * is an instant operation as oposed to an ongoing reshape.
3182 		 */
3183 
3184 		/* We can't reshape a journaled raid4/5/6 */
3185 		if (test_bit(__CTR_FLAG_JOURNAL_DEV, &rs->ctr_flags)) {
3186 			ti->error = "Can't reshape a journaled raid4/5/6 set";
3187 			r = -EPERM;
3188 			goto bad;
3189 		}
3190 
3191 		/* Out-of-place space has to be available to allow for a reshape unless raid1! */
3192 		if (reshape_sectors || rs_is_raid1(rs)) {
3193 			/*
3194 			  * We can only prepare for a reshape here, because the
3195 			  * raid set needs to run to provide the repective reshape
3196 			  * check functions via its MD personality instance.
3197 			  *
3198 			  * So do the reshape check after md_run() succeeded.
3199 			  */
3200 			r = rs_prepare_reshape(rs);
3201 			if (r)
3202 				return r;
3203 
3204 			/* Reshaping ain't recovery, so disable recovery */
3205 			rs_setup_recovery(rs, MaxSector);
3206 		}
3207 		rs_set_cur(rs);
3208 	} else {
3209 		/* May not set recovery when a device rebuild is requested */
3210 		if (test_bit(__CTR_FLAG_REBUILD, &rs->ctr_flags)) {
3211 			rs_setup_recovery(rs, MaxSector);
3212 			set_bit(RT_FLAG_UPDATE_SBS, &rs->runtime_flags);
3213 		} else
3214 			rs_setup_recovery(rs, test_bit(__CTR_FLAG_SYNC, &rs->ctr_flags) ?
3215 					      0 : (resize ? calculated_dev_sectors : MaxSector));
3216 		rs_set_cur(rs);
3217 	}
3218 
3219 	/* If constructor requested it, change data and new_data offsets */
3220 	r = rs_adjust_data_offsets(rs);
3221 	if (r)
3222 		goto bad;
3223 
3224 	/* Start raid set read-only and assumed clean to change in raid_resume() */
3225 	rs->md.ro = 1;
3226 	rs->md.in_sync = 1;
3227 
3228 	/* Keep array frozen */
3229 	set_bit(MD_RECOVERY_FROZEN, &rs->md.recovery);
3230 
3231 	/* Has to be held on running the array */
3232 	mddev_lock_nointr(&rs->md);
3233 	r = md_run(&rs->md);
3234 	rs->md.in_sync = 0; /* Assume already marked dirty */
3235 	if (r) {
3236 		ti->error = "Failed to run raid array";
3237 		mddev_unlock(&rs->md);
3238 		goto bad;
3239 	}
3240 
3241 	r = md_start(&rs->md);
3242 
3243 	if (r) {
3244 		ti->error = "Failed to start raid array";
3245 		mddev_unlock(&rs->md);
3246 		goto bad_md_start;
3247 	}
3248 
3249 	rs->callbacks.congested_fn = raid_is_congested;
3250 	dm_table_add_target_callbacks(ti->table, &rs->callbacks);
3251 
3252 	/* If raid4/5/6 journal mode explicitly requested (only possible with journal dev) -> set it */
3253 	if (test_bit(__CTR_FLAG_JOURNAL_MODE, &rs->ctr_flags)) {
3254 		r = r5c_journal_mode_set(&rs->md, rs->journal_dev.mode);
3255 		if (r) {
3256 			ti->error = "Failed to set raid4/5/6 journal mode";
3257 			mddev_unlock(&rs->md);
3258 			goto bad_journal_mode_set;
3259 		}
3260 	}
3261 
3262 	mddev_suspend(&rs->md);
3263 	set_bit(RT_FLAG_RS_SUSPENDED, &rs->runtime_flags);
3264 
3265 	/* Try to adjust the raid4/5/6 stripe cache size to the stripe size */
3266 	if (rs_is_raid456(rs)) {
3267 		r = rs_set_raid456_stripe_cache(rs);
3268 		if (r)
3269 			goto bad_stripe_cache;
3270 	}
3271 
3272 	/* Now do an early reshape check */
3273 	if (test_bit(RT_FLAG_RESHAPE_RS, &rs->runtime_flags)) {
3274 		r = rs_check_reshape(rs);
3275 		if (r)
3276 			goto bad_check_reshape;
3277 
3278 		/* Restore new, ctr requested layout to perform check */
3279 		rs_config_restore(rs, &rs_layout);
3280 
3281 		if (rs->md.pers->start_reshape) {
3282 			r = rs->md.pers->check_reshape(&rs->md);
3283 			if (r) {
3284 				ti->error = "Reshape check failed";
3285 				goto bad_check_reshape;
3286 			}
3287 		}
3288 	}
3289 
3290 	/* Disable/enable discard support on raid set. */
3291 	configure_discard_support(rs);
3292 
3293 	mddev_unlock(&rs->md);
3294 	return 0;
3295 
3296 bad_md_start:
3297 bad_journal_mode_set:
3298 bad_stripe_cache:
3299 bad_check_reshape:
3300 	md_stop(&rs->md);
3301 bad:
3302 	raid_set_free(rs);
3303 
3304 	return r;
3305 }
3306 
3307 static void raid_dtr(struct dm_target *ti)
3308 {
3309 	struct raid_set *rs = ti->private;
3310 
3311 	list_del_init(&rs->callbacks.list);
3312 	md_stop(&rs->md);
3313 	raid_set_free(rs);
3314 }
3315 
3316 static int raid_map(struct dm_target *ti, struct bio *bio)
3317 {
3318 	struct raid_set *rs = ti->private;
3319 	struct mddev *mddev = &rs->md;
3320 
3321 	/*
3322 	 * If we're reshaping to add disk(s)), ti->len and
3323 	 * mddev->array_sectors will differ during the process
3324 	 * (ti->len > mddev->array_sectors), so we have to requeue
3325 	 * bios with addresses > mddev->array_sectors here or
3326 	 * there will occur accesses past EOD of the component
3327 	 * data images thus erroring the raid set.
3328 	 */
3329 	if (unlikely(bio_end_sector(bio) > mddev->array_sectors))
3330 		return DM_MAPIO_REQUEUE;
3331 
3332 	md_handle_request(mddev, bio);
3333 
3334 	return DM_MAPIO_SUBMITTED;
3335 }
3336 
3337 /* Return sync state string for @state */
3338 enum sync_state { st_frozen, st_reshape, st_resync, st_check, st_repair, st_recover, st_idle };
3339 static const char *sync_str(enum sync_state state)
3340 {
3341 	/* Has to be in above sync_state order! */
3342 	static const char *sync_strs[] = {
3343 		"frozen",
3344 		"reshape",
3345 		"resync",
3346 		"check",
3347 		"repair",
3348 		"recover",
3349 		"idle"
3350 	};
3351 
3352 	return __within_range(state, 0, ARRAY_SIZE(sync_strs) - 1) ? sync_strs[state] : "undef";
3353 };
3354 
3355 /* Return enum sync_state for @mddev derived from @recovery flags */
3356 static enum sync_state decipher_sync_action(struct mddev *mddev, unsigned long recovery)
3357 {
3358 	if (test_bit(MD_RECOVERY_FROZEN, &recovery))
3359 		return st_frozen;
3360 
3361 	/* The MD sync thread can be done with io or be interrupted but still be running */
3362 	if (!test_bit(MD_RECOVERY_DONE, &recovery) &&
3363 	    (test_bit(MD_RECOVERY_RUNNING, &recovery) ||
3364 	     (!mddev->ro && test_bit(MD_RECOVERY_NEEDED, &recovery)))) {
3365 		if (test_bit(MD_RECOVERY_RESHAPE, &recovery))
3366 			return st_reshape;
3367 
3368 		if (test_bit(MD_RECOVERY_SYNC, &recovery)) {
3369 			if (!test_bit(MD_RECOVERY_REQUESTED, &recovery))
3370 				return st_resync;
3371 			if (test_bit(MD_RECOVERY_CHECK, &recovery))
3372 				return st_check;
3373 			return st_repair;
3374 		}
3375 
3376 		if (test_bit(MD_RECOVERY_RECOVER, &recovery))
3377 			return st_recover;
3378 
3379 		if (mddev->reshape_position != MaxSector)
3380 			return st_reshape;
3381 	}
3382 
3383 	return st_idle;
3384 }
3385 
3386 /*
3387  * Return status string for @rdev
3388  *
3389  * Status characters:
3390  *
3391  *  'D' = Dead/Failed raid set component or raid4/5/6 journal device
3392  *  'a' = Alive but not in-sync raid set component _or_ alive raid4/5/6 'write_back' journal device
3393  *  'A' = Alive and in-sync raid set component _or_ alive raid4/5/6 'write_through' journal device
3394  *  '-' = Non-existing device (i.e. uspace passed '- -' into the ctr)
3395  */
3396 static const char *__raid_dev_status(struct raid_set *rs, struct md_rdev *rdev)
3397 {
3398 	if (!rdev->bdev)
3399 		return "-";
3400 	else if (test_bit(Faulty, &rdev->flags))
3401 		return "D";
3402 	else if (test_bit(Journal, &rdev->flags))
3403 		return (rs->journal_dev.mode == R5C_JOURNAL_MODE_WRITE_THROUGH) ? "A" : "a";
3404 	else if (test_bit(RT_FLAG_RS_RESYNCING, &rs->runtime_flags) ||
3405 		 (!test_bit(RT_FLAG_RS_IN_SYNC, &rs->runtime_flags) &&
3406 		  !test_bit(In_sync, &rdev->flags)))
3407 		return "a";
3408 	else
3409 		return "A";
3410 }
3411 
3412 /* Helper to return resync/reshape progress for @rs and runtime flags for raid set in sync / resynching */
3413 static sector_t rs_get_progress(struct raid_set *rs, unsigned long recovery,
3414 				sector_t resync_max_sectors)
3415 {
3416 	sector_t r;
3417 	enum sync_state state;
3418 	struct mddev *mddev = &rs->md;
3419 
3420 	clear_bit(RT_FLAG_RS_IN_SYNC, &rs->runtime_flags);
3421 	clear_bit(RT_FLAG_RS_RESYNCING, &rs->runtime_flags);
3422 
3423 	if (rs_is_raid0(rs)) {
3424 		r = resync_max_sectors;
3425 		set_bit(RT_FLAG_RS_IN_SYNC, &rs->runtime_flags);
3426 
3427 	} else {
3428 		state = decipher_sync_action(mddev, recovery);
3429 
3430 		if (state == st_idle && !test_bit(MD_RECOVERY_INTR, &recovery))
3431 			r = mddev->recovery_cp;
3432 		else
3433 			r = mddev->curr_resync_completed;
3434 
3435 		if (state == st_idle && r >= resync_max_sectors) {
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 (state == st_recover)
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 		else if (state == st_resync)
3450 			/*
3451 			 * If "resync" is occurring, the raid set
3452 			 * is or may be out of sync hence the health
3453 			 * characters shall be 'a'.
3454 			 */
3455 			set_bit(RT_FLAG_RS_RESYNCING, &rs->runtime_flags);
3456 		else if (state == st_reshape)
3457 			/*
3458 			 * If "reshape" is occurring, the raid set
3459 			 * is or may be out of sync hence the health
3460 			 * characters shall be 'a'.
3461 			 */
3462 			set_bit(RT_FLAG_RS_RESYNCING, &rs->runtime_flags);
3463 
3464 		else if (state == st_check || state == st_repair)
3465 			/*
3466 			 * If "check" or "repair" is occurring, the raid set has
3467 			 * undergone an initial sync and the health characters
3468 			 * should not be 'a' anymore.
3469 			 */
3470 			set_bit(RT_FLAG_RS_IN_SYNC, &rs->runtime_flags);
3471 
3472 		else {
3473 			struct md_rdev *rdev;
3474 
3475 			/*
3476 			 * We are idle and recovery is needed, prevent 'A' chars race
3477 			 * caused by components still set to in-sync by constructor.
3478 			 */
3479 			if (test_bit(MD_RECOVERY_NEEDED, &recovery))
3480 				set_bit(RT_FLAG_RS_RESYNCING, &rs->runtime_flags);
3481 
3482 			/*
3483 			 * The raid set may be doing an initial sync, or it may
3484 			 * be rebuilding individual components.	 If all the
3485 			 * devices are In_sync, then it is the raid set that is
3486 			 * being initialized.
3487 			 */
3488 			set_bit(RT_FLAG_RS_IN_SYNC, &rs->runtime_flags);
3489 			rdev_for_each(rdev, mddev)
3490 				if (!test_bit(Journal, &rdev->flags) &&
3491 				    !test_bit(In_sync, &rdev->flags)) {
3492 					clear_bit(RT_FLAG_RS_IN_SYNC, &rs->runtime_flags);
3493 					break;
3494 				}
3495 		}
3496 	}
3497 
3498 	return min(r, resync_max_sectors);
3499 }
3500 
3501 /* Helper to return @dev name or "-" if !@dev */
3502 static const char *__get_dev_name(struct dm_dev *dev)
3503 {
3504 	return dev ? dev->name : "-";
3505 }
3506 
3507 static void raid_status(struct dm_target *ti, status_type_t type,
3508 			unsigned int status_flags, char *result, unsigned int maxlen)
3509 {
3510 	struct raid_set *rs = ti->private;
3511 	struct mddev *mddev = &rs->md;
3512 	struct r5conf *conf = mddev->private;
3513 	int i, max_nr_stripes = conf ? conf->max_nr_stripes : 0;
3514 	unsigned long recovery;
3515 	unsigned int raid_param_cnt = 1; /* at least 1 for chunksize */
3516 	unsigned int sz = 0;
3517 	unsigned int rebuild_disks;
3518 	unsigned int write_mostly_params = 0;
3519 	sector_t progress, resync_max_sectors, resync_mismatches;
3520 	const char *sync_action;
3521 	struct raid_type *rt;
3522 
3523 	switch (type) {
3524 	case STATUSTYPE_INFO:
3525 		/* *Should* always succeed */
3526 		rt = get_raid_type_by_ll(mddev->new_level, mddev->new_layout);
3527 		if (!rt)
3528 			return;
3529 
3530 		DMEMIT("%s %d ", rt->name, mddev->raid_disks);
3531 
3532 		/* Access most recent mddev properties for status output */
3533 		smp_rmb();
3534 		recovery = rs->md.recovery;
3535 		/* Get sensible max sectors even if raid set not yet started */
3536 		resync_max_sectors = test_bit(RT_FLAG_RS_PRERESUMED, &rs->runtime_flags) ?
3537 				      mddev->resync_max_sectors : mddev->dev_sectors;
3538 		progress = rs_get_progress(rs, recovery, resync_max_sectors);
3539 		resync_mismatches = (mddev->last_sync_action && !strcasecmp(mddev->last_sync_action, "check")) ?
3540 				    atomic64_read(&mddev->resync_mismatches) : 0;
3541 		sync_action = sync_str(decipher_sync_action(&rs->md, recovery));
3542 
3543 		/* HM FIXME: do we want another state char for raid0? It shows 'D'/'A'/'-' now */
3544 		for (i = 0; i < rs->raid_disks; i++)
3545 			DMEMIT(__raid_dev_status(rs, &rs->dev[i].rdev));
3546 
3547 		/*
3548 		 * In-sync/Reshape ratio:
3549 		 *  The in-sync ratio shows the progress of:
3550 		 *   - Initializing the raid set
3551 		 *   - Rebuilding a subset of devices of the raid set
3552 		 *  The user can distinguish between the two by referring
3553 		 *  to the status characters.
3554 		 *
3555 		 *  The reshape ratio shows the progress of
3556 		 *  changing the raid layout or the number of
3557 		 *  disks of a raid set
3558 		 */
3559 		DMEMIT(" %llu/%llu", (unsigned long long) progress,
3560 				     (unsigned long long) resync_max_sectors);
3561 
3562 		/*
3563 		 * v1.5.0+:
3564 		 *
3565 		 * Sync action:
3566 		 *   See Documentation/device-mapper/dm-raid.txt for
3567 		 *   information on each of these states.
3568 		 */
3569 		DMEMIT(" %s", sync_action);
3570 
3571 		/*
3572 		 * v1.5.0+:
3573 		 *
3574 		 * resync_mismatches/mismatch_cnt
3575 		 *   This field shows the number of discrepancies found when
3576 		 *   performing a "check" of the raid set.
3577 		 */
3578 		DMEMIT(" %llu", (unsigned long long) resync_mismatches);
3579 
3580 		/*
3581 		 * v1.9.0+:
3582 		 *
3583 		 * data_offset (needed for out of space reshaping)
3584 		 *   This field shows the data offset into the data
3585 		 *   image LV where the first stripes data starts.
3586 		 *
3587 		 * We keep data_offset equal on all raid disks of the set,
3588 		 * so retrieving it from the first raid disk is sufficient.
3589 		 */
3590 		DMEMIT(" %llu", (unsigned long long) rs->dev[0].rdev.data_offset);
3591 
3592 		/*
3593 		 * v1.10.0+:
3594 		 */
3595 		DMEMIT(" %s", test_bit(__CTR_FLAG_JOURNAL_DEV, &rs->ctr_flags) ?
3596 			      __raid_dev_status(rs, &rs->journal_dev.rdev) : "-");
3597 		break;
3598 
3599 	case STATUSTYPE_TABLE:
3600 		/* Report the table line string you would use to construct this raid set */
3601 
3602 		/* Calculate raid parameter count */
3603 		for (i = 0; i < rs->raid_disks; i++)
3604 			if (test_bit(WriteMostly, &rs->dev[i].rdev.flags))
3605 				write_mostly_params += 2;
3606 		rebuild_disks = memweight(rs->rebuild_disks, DISKS_ARRAY_ELEMS * sizeof(*rs->rebuild_disks));
3607 		raid_param_cnt += rebuild_disks * 2 +
3608 				  write_mostly_params +
3609 				  hweight32(rs->ctr_flags & CTR_FLAG_OPTIONS_NO_ARGS) +
3610 				  hweight32(rs->ctr_flags & CTR_FLAG_OPTIONS_ONE_ARG) * 2 +
3611 				  (test_bit(__CTR_FLAG_JOURNAL_DEV, &rs->ctr_flags) ? 2 : 0) +
3612 				  (test_bit(__CTR_FLAG_JOURNAL_MODE, &rs->ctr_flags) ? 2 : 0);
3613 
3614 		/* Emit table line */
3615 		/* This has to be in the documented order for userspace! */
3616 		DMEMIT("%s %u %u", rs->raid_type->name, raid_param_cnt, mddev->new_chunk_sectors);
3617 		if (test_bit(__CTR_FLAG_SYNC, &rs->ctr_flags))
3618 			DMEMIT(" %s", dm_raid_arg_name_by_flag(CTR_FLAG_SYNC));
3619 		if (test_bit(__CTR_FLAG_NOSYNC, &rs->ctr_flags))
3620 			DMEMIT(" %s", dm_raid_arg_name_by_flag(CTR_FLAG_NOSYNC));
3621 		if (rebuild_disks)
3622 			for (i = 0; i < rs->raid_disks; i++)
3623 				if (test_bit(rs->dev[i].rdev.raid_disk, (void *) rs->rebuild_disks))
3624 					DMEMIT(" %s %u", dm_raid_arg_name_by_flag(CTR_FLAG_REBUILD),
3625 							 rs->dev[i].rdev.raid_disk);
3626 		if (test_bit(__CTR_FLAG_DAEMON_SLEEP, &rs->ctr_flags))
3627 			DMEMIT(" %s %lu", dm_raid_arg_name_by_flag(CTR_FLAG_DAEMON_SLEEP),
3628 					  mddev->bitmap_info.daemon_sleep);
3629 		if (test_bit(__CTR_FLAG_MIN_RECOVERY_RATE, &rs->ctr_flags))
3630 			DMEMIT(" %s %d", dm_raid_arg_name_by_flag(CTR_FLAG_MIN_RECOVERY_RATE),
3631 					 mddev->sync_speed_min);
3632 		if (test_bit(__CTR_FLAG_MAX_RECOVERY_RATE, &rs->ctr_flags))
3633 			DMEMIT(" %s %d", dm_raid_arg_name_by_flag(CTR_FLAG_MAX_RECOVERY_RATE),
3634 					 mddev->sync_speed_max);
3635 		if (write_mostly_params)
3636 			for (i = 0; i < rs->raid_disks; i++)
3637 				if (test_bit(WriteMostly, &rs->dev[i].rdev.flags))
3638 					DMEMIT(" %s %d", dm_raid_arg_name_by_flag(CTR_FLAG_WRITE_MOSTLY),
3639 					       rs->dev[i].rdev.raid_disk);
3640 		if (test_bit(__CTR_FLAG_MAX_WRITE_BEHIND, &rs->ctr_flags))
3641 			DMEMIT(" %s %lu", dm_raid_arg_name_by_flag(CTR_FLAG_MAX_WRITE_BEHIND),
3642 					  mddev->bitmap_info.max_write_behind);
3643 		if (test_bit(__CTR_FLAG_STRIPE_CACHE, &rs->ctr_flags))
3644 			DMEMIT(" %s %d", dm_raid_arg_name_by_flag(CTR_FLAG_STRIPE_CACHE),
3645 					 max_nr_stripes);
3646 		if (test_bit(__CTR_FLAG_REGION_SIZE, &rs->ctr_flags))
3647 			DMEMIT(" %s %llu", dm_raid_arg_name_by_flag(CTR_FLAG_REGION_SIZE),
3648 					   (unsigned long long) to_sector(mddev->bitmap_info.chunksize));
3649 		if (test_bit(__CTR_FLAG_RAID10_COPIES, &rs->ctr_flags))
3650 			DMEMIT(" %s %d", dm_raid_arg_name_by_flag(CTR_FLAG_RAID10_COPIES),
3651 					 raid10_md_layout_to_copies(mddev->layout));
3652 		if (test_bit(__CTR_FLAG_RAID10_FORMAT, &rs->ctr_flags))
3653 			DMEMIT(" %s %s", dm_raid_arg_name_by_flag(CTR_FLAG_RAID10_FORMAT),
3654 					 raid10_md_layout_to_format(mddev->layout));
3655 		if (test_bit(__CTR_FLAG_DELTA_DISKS, &rs->ctr_flags))
3656 			DMEMIT(" %s %d", dm_raid_arg_name_by_flag(CTR_FLAG_DELTA_DISKS),
3657 					 max(rs->delta_disks, mddev->delta_disks));
3658 		if (test_bit(__CTR_FLAG_DATA_OFFSET, &rs->ctr_flags))
3659 			DMEMIT(" %s %llu", dm_raid_arg_name_by_flag(CTR_FLAG_DATA_OFFSET),
3660 					   (unsigned long long) rs->data_offset);
3661 		if (test_bit(__CTR_FLAG_JOURNAL_DEV, &rs->ctr_flags))
3662 			DMEMIT(" %s %s", dm_raid_arg_name_by_flag(CTR_FLAG_JOURNAL_DEV),
3663 					__get_dev_name(rs->journal_dev.dev));
3664 		if (test_bit(__CTR_FLAG_JOURNAL_MODE, &rs->ctr_flags))
3665 			DMEMIT(" %s %s", dm_raid_arg_name_by_flag(CTR_FLAG_JOURNAL_MODE),
3666 					 md_journal_mode_to_dm_raid(rs->journal_dev.mode));
3667 		DMEMIT(" %d", rs->raid_disks);
3668 		for (i = 0; i < rs->raid_disks; i++)
3669 			DMEMIT(" %s %s", __get_dev_name(rs->dev[i].meta_dev),
3670 					 __get_dev_name(rs->dev[i].data_dev));
3671 	}
3672 }
3673 
3674 static int raid_message(struct dm_target *ti, unsigned int argc, char **argv,
3675 			char *result, unsigned maxlen)
3676 {
3677 	struct raid_set *rs = ti->private;
3678 	struct mddev *mddev = &rs->md;
3679 
3680 	if (!mddev->pers || !mddev->pers->sync_request)
3681 		return -EINVAL;
3682 
3683 	if (!strcasecmp(argv[0], "frozen"))
3684 		set_bit(MD_RECOVERY_FROZEN, &mddev->recovery);
3685 	else
3686 		clear_bit(MD_RECOVERY_FROZEN, &mddev->recovery);
3687 
3688 	if (!strcasecmp(argv[0], "idle") || !strcasecmp(argv[0], "frozen")) {
3689 		if (mddev->sync_thread) {
3690 			set_bit(MD_RECOVERY_INTR, &mddev->recovery);
3691 			md_reap_sync_thread(mddev);
3692 		}
3693 	} else if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery) ||
3694 		   test_bit(MD_RECOVERY_NEEDED, &mddev->recovery))
3695 		return -EBUSY;
3696 	else if (!strcasecmp(argv[0], "resync"))
3697 		; /* MD_RECOVERY_NEEDED set below */
3698 	else if (!strcasecmp(argv[0], "recover"))
3699 		set_bit(MD_RECOVERY_RECOVER, &mddev->recovery);
3700 	else {
3701 		if (!strcasecmp(argv[0], "check")) {
3702 			set_bit(MD_RECOVERY_CHECK, &mddev->recovery);
3703 			set_bit(MD_RECOVERY_REQUESTED, &mddev->recovery);
3704 			set_bit(MD_RECOVERY_SYNC, &mddev->recovery);
3705 		} else if (!strcasecmp(argv[0], "repair")) {
3706 			set_bit(MD_RECOVERY_REQUESTED, &mddev->recovery);
3707 			set_bit(MD_RECOVERY_SYNC, &mddev->recovery);
3708 		} else
3709 			return -EINVAL;
3710 	}
3711 	if (mddev->ro == 2) {
3712 		/* A write to sync_action is enough to justify
3713 		 * canceling read-auto mode
3714 		 */
3715 		mddev->ro = 0;
3716 		if (!mddev->suspended && mddev->sync_thread)
3717 			md_wakeup_thread(mddev->sync_thread);
3718 	}
3719 	set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
3720 	if (!mddev->suspended && mddev->thread)
3721 		md_wakeup_thread(mddev->thread);
3722 
3723 	return 0;
3724 }
3725 
3726 static int raid_iterate_devices(struct dm_target *ti,
3727 				iterate_devices_callout_fn fn, void *data)
3728 {
3729 	struct raid_set *rs = ti->private;
3730 	unsigned int i;
3731 	int r = 0;
3732 
3733 	for (i = 0; !r && i < rs->md.raid_disks; i++)
3734 		if (rs->dev[i].data_dev)
3735 			r = fn(ti,
3736 				 rs->dev[i].data_dev,
3737 				 0, /* No offset on data devs */
3738 				 rs->md.dev_sectors,
3739 				 data);
3740 
3741 	return r;
3742 }
3743 
3744 static void raid_io_hints(struct dm_target *ti, struct queue_limits *limits)
3745 {
3746 	struct raid_set *rs = ti->private;
3747 	unsigned int chunk_size = to_bytes(rs->md.chunk_sectors);
3748 
3749 	blk_limits_io_min(limits, chunk_size);
3750 	blk_limits_io_opt(limits, chunk_size * mddev_data_stripes(rs));
3751 }
3752 
3753 static void raid_postsuspend(struct dm_target *ti)
3754 {
3755 	struct raid_set *rs = ti->private;
3756 
3757 	if (!test_and_set_bit(RT_FLAG_RS_SUSPENDED, &rs->runtime_flags)) {
3758 		/* Writes have to be stopped before suspending to avoid deadlocks. */
3759 		if (!test_bit(MD_RECOVERY_FROZEN, &rs->md.recovery))
3760 			md_stop_writes(&rs->md);
3761 
3762 		mddev_lock_nointr(&rs->md);
3763 		mddev_suspend(&rs->md);
3764 		mddev_unlock(&rs->md);
3765 	}
3766 }
3767 
3768 static void attempt_restore_of_faulty_devices(struct raid_set *rs)
3769 {
3770 	int i;
3771 	uint64_t cleared_failed_devices[DISKS_ARRAY_ELEMS];
3772 	unsigned long flags;
3773 	bool cleared = false;
3774 	struct dm_raid_superblock *sb;
3775 	struct mddev *mddev = &rs->md;
3776 	struct md_rdev *r;
3777 
3778 	/* RAID personalities have to provide hot add/remove methods or we need to bail out. */
3779 	if (!mddev->pers || !mddev->pers->hot_add_disk || !mddev->pers->hot_remove_disk)
3780 		return;
3781 
3782 	memset(cleared_failed_devices, 0, sizeof(cleared_failed_devices));
3783 
3784 	for (i = 0; i < mddev->raid_disks; i++) {
3785 		r = &rs->dev[i].rdev;
3786 		/* HM FIXME: enhance journal device recovery processing */
3787 		if (test_bit(Journal, &r->flags))
3788 			continue;
3789 
3790 		if (test_bit(Faulty, &r->flags) &&
3791 		    r->meta_bdev && !read_disk_sb(r, r->sb_size, true)) {
3792 			DMINFO("Faulty %s device #%d has readable super block."
3793 			       "  Attempting to revive it.",
3794 			       rs->raid_type->name, i);
3795 
3796 			/*
3797 			 * Faulty bit may be set, but sometimes the array can
3798 			 * be suspended before the personalities can respond
3799 			 * by removing the device from the array (i.e. calling
3800 			 * 'hot_remove_disk').	If they haven't yet removed
3801 			 * the failed device, its 'raid_disk' number will be
3802 			 * '>= 0' - meaning we must call this function
3803 			 * ourselves.
3804 			 */
3805 			flags = r->flags;
3806 			clear_bit(In_sync, &r->flags); /* Mandatory for hot remove. */
3807 			if (r->raid_disk >= 0) {
3808 				if (mddev->pers->hot_remove_disk(mddev, r)) {
3809 					/* Failed to revive this device, try next */
3810 					r->flags = flags;
3811 					continue;
3812 				}
3813 			} else
3814 				r->raid_disk = r->saved_raid_disk = i;
3815 
3816 			clear_bit(Faulty, &r->flags);
3817 			clear_bit(WriteErrorSeen, &r->flags);
3818 
3819 			if (mddev->pers->hot_add_disk(mddev, r)) {
3820 				/* Failed to revive this device, try next */
3821 				r->raid_disk = r->saved_raid_disk = -1;
3822 				r->flags = flags;
3823 			} else {
3824 				clear_bit(In_sync, &r->flags);
3825 				r->recovery_offset = 0;
3826 				set_bit(i, (void *) cleared_failed_devices);
3827 				cleared = true;
3828 			}
3829 		}
3830 	}
3831 
3832 	/* If any failed devices could be cleared, update all sbs failed_devices bits */
3833 	if (cleared) {
3834 		uint64_t failed_devices[DISKS_ARRAY_ELEMS];
3835 
3836 		rdev_for_each(r, &rs->md) {
3837 			if (test_bit(Journal, &r->flags))
3838 				continue;
3839 
3840 			sb = page_address(r->sb_page);
3841 			sb_retrieve_failed_devices(sb, failed_devices);
3842 
3843 			for (i = 0; i < DISKS_ARRAY_ELEMS; i++)
3844 				failed_devices[i] &= ~cleared_failed_devices[i];
3845 
3846 			sb_update_failed_devices(sb, failed_devices);
3847 		}
3848 	}
3849 }
3850 
3851 static int __load_dirty_region_bitmap(struct raid_set *rs)
3852 {
3853 	int r = 0;
3854 
3855 	/* Try loading the bitmap unless "raid0", which does not have one */
3856 	if (!rs_is_raid0(rs) &&
3857 	    !test_and_set_bit(RT_FLAG_RS_BITMAP_LOADED, &rs->runtime_flags)) {
3858 		r = md_bitmap_load(&rs->md);
3859 		if (r)
3860 			DMERR("Failed to load bitmap");
3861 	}
3862 
3863 	return r;
3864 }
3865 
3866 /* Enforce updating all superblocks */
3867 static void rs_update_sbs(struct raid_set *rs)
3868 {
3869 	struct mddev *mddev = &rs->md;
3870 	int ro = mddev->ro;
3871 
3872 	set_bit(MD_SB_CHANGE_DEVS, &mddev->sb_flags);
3873 	mddev->ro = 0;
3874 	md_update_sb(mddev, 1);
3875 	mddev->ro = ro;
3876 }
3877 
3878 /*
3879  * Reshape changes raid algorithm of @rs to new one within personality
3880  * (e.g. raid6_zr -> raid6_nc), changes stripe size, adds/removes
3881  * disks from a raid set thus growing/shrinking it or resizes the set
3882  *
3883  * Call mddev_lock_nointr() before!
3884  */
3885 static int rs_start_reshape(struct raid_set *rs)
3886 {
3887 	int r;
3888 	struct mddev *mddev = &rs->md;
3889 	struct md_personality *pers = mddev->pers;
3890 
3891 	/* Don't allow the sync thread to work until the table gets reloaded. */
3892 	set_bit(MD_RECOVERY_WAIT, &mddev->recovery);
3893 
3894 	r = rs_setup_reshape(rs);
3895 	if (r)
3896 		return r;
3897 
3898 	/*
3899 	 * Check any reshape constraints enforced by the personalility
3900 	 *
3901 	 * May as well already kick the reshape off so that * pers->start_reshape() becomes optional.
3902 	 */
3903 	r = pers->check_reshape(mddev);
3904 	if (r) {
3905 		rs->ti->error = "pers->check_reshape() failed";
3906 		return r;
3907 	}
3908 
3909 	/*
3910 	 * Personality may not provide start reshape method in which
3911 	 * case check_reshape above has already covered everything
3912 	 */
3913 	if (pers->start_reshape) {
3914 		r = pers->start_reshape(mddev);
3915 		if (r) {
3916 			rs->ti->error = "pers->start_reshape() failed";
3917 			return r;
3918 		}
3919 	}
3920 
3921 	/*
3922 	 * Now reshape got set up, update superblocks to
3923 	 * reflect the fact so that a table reload will
3924 	 * access proper superblock content in the ctr.
3925 	 */
3926 	rs_update_sbs(rs);
3927 
3928 	return 0;
3929 }
3930 
3931 static int raid_preresume(struct dm_target *ti)
3932 {
3933 	int r;
3934 	struct raid_set *rs = ti->private;
3935 	struct mddev *mddev = &rs->md;
3936 
3937 	/* This is a resume after a suspend of the set -> it's already started. */
3938 	if (test_and_set_bit(RT_FLAG_RS_PRERESUMED, &rs->runtime_flags))
3939 		return 0;
3940 
3941 	/*
3942 	 * The superblocks need to be updated on disk if the
3943 	 * array is new or new devices got added (thus zeroed
3944 	 * out by userspace) or __load_dirty_region_bitmap
3945 	 * will overwrite them in core with old data or fail.
3946 	 */
3947 	if (test_bit(RT_FLAG_UPDATE_SBS, &rs->runtime_flags))
3948 		rs_update_sbs(rs);
3949 
3950 	/* Load the bitmap from disk unless raid0 */
3951 	r = __load_dirty_region_bitmap(rs);
3952 	if (r)
3953 		return r;
3954 
3955 	/* Resize bitmap to adjust to changed region size (aka MD bitmap chunksize) */
3956 	if (test_bit(RT_FLAG_RS_BITMAP_LOADED, &rs->runtime_flags) && mddev->bitmap &&
3957 	    mddev->bitmap_info.chunksize != to_bytes(rs->requested_bitmap_chunk_sectors)) {
3958 		r = md_bitmap_resize(mddev->bitmap, mddev->dev_sectors,
3959 				     to_bytes(rs->requested_bitmap_chunk_sectors), 0);
3960 		if (r)
3961 			DMERR("Failed to resize bitmap");
3962 	}
3963 
3964 	/* Check for any resize/reshape on @rs and adjust/initiate */
3965 	/* Be prepared for mddev_resume() in raid_resume() */
3966 	set_bit(MD_RECOVERY_FROZEN, &mddev->recovery);
3967 	if (mddev->recovery_cp && mddev->recovery_cp < MaxSector) {
3968 		set_bit(MD_RECOVERY_SYNC, &mddev->recovery);
3969 		mddev->resync_min = mddev->recovery_cp;
3970 	}
3971 
3972 	/* Check for any reshape request unless new raid set */
3973 	if (test_bit(RT_FLAG_RESHAPE_RS, &rs->runtime_flags)) {
3974 		/* Initiate a reshape. */
3975 		rs_set_rdev_sectors(rs);
3976 		mddev_lock_nointr(mddev);
3977 		r = rs_start_reshape(rs);
3978 		mddev_unlock(mddev);
3979 		if (r)
3980 			DMWARN("Failed to check/start reshape, continuing without change");
3981 		r = 0;
3982 	}
3983 
3984 	return r;
3985 }
3986 
3987 static void raid_resume(struct dm_target *ti)
3988 {
3989 	struct raid_set *rs = ti->private;
3990 	struct mddev *mddev = &rs->md;
3991 
3992 	if (test_and_set_bit(RT_FLAG_RS_RESUMED, &rs->runtime_flags)) {
3993 		/*
3994 		 * A secondary resume while the device is active.
3995 		 * Take this opportunity to check whether any failed
3996 		 * devices are reachable again.
3997 		 */
3998 		attempt_restore_of_faulty_devices(rs);
3999 	}
4000 
4001 	if (test_and_clear_bit(RT_FLAG_RS_SUSPENDED, &rs->runtime_flags)) {
4002 		/* Only reduce raid set size before running a disk removing reshape. */
4003 		if (mddev->delta_disks < 0)
4004 			rs_set_capacity(rs);
4005 
4006 		mddev_lock_nointr(mddev);
4007 		clear_bit(MD_RECOVERY_FROZEN, &mddev->recovery);
4008 		mddev->ro = 0;
4009 		mddev->in_sync = 0;
4010 		mddev_resume(mddev);
4011 		mddev_unlock(mddev);
4012 	}
4013 }
4014 
4015 static struct target_type raid_target = {
4016 	.name = "raid",
4017 	.version = {1, 14, 0},
4018 	.module = THIS_MODULE,
4019 	.ctr = raid_ctr,
4020 	.dtr = raid_dtr,
4021 	.map = raid_map,
4022 	.status = raid_status,
4023 	.message = raid_message,
4024 	.iterate_devices = raid_iterate_devices,
4025 	.io_hints = raid_io_hints,
4026 	.postsuspend = raid_postsuspend,
4027 	.preresume = raid_preresume,
4028 	.resume = raid_resume,
4029 };
4030 
4031 static int __init dm_raid_init(void)
4032 {
4033 	DMINFO("Loading target version %u.%u.%u",
4034 	       raid_target.version[0],
4035 	       raid_target.version[1],
4036 	       raid_target.version[2]);
4037 	return dm_register_target(&raid_target);
4038 }
4039 
4040 static void __exit dm_raid_exit(void)
4041 {
4042 	dm_unregister_target(&raid_target);
4043 }
4044 
4045 module_init(dm_raid_init);
4046 module_exit(dm_raid_exit);
4047 
4048 module_param(devices_handle_discard_safely, bool, 0644);
4049 MODULE_PARM_DESC(devices_handle_discard_safely,
4050 		 "Set to Y if all devices in each array reliably return zeroes on reads from discarded regions");
4051 
4052 MODULE_DESCRIPTION(DM_NAME " raid0/1/10/4/5/6 target");
4053 MODULE_ALIAS("dm-raid0");
4054 MODULE_ALIAS("dm-raid1");
4055 MODULE_ALIAS("dm-raid10");
4056 MODULE_ALIAS("dm-raid4");
4057 MODULE_ALIAS("dm-raid5");
4058 MODULE_ALIAS("dm-raid6");
4059 MODULE_AUTHOR("Neil Brown <dm-devel@redhat.com>");
4060 MODULE_AUTHOR("Heinz Mauelshagen <dm-devel@redhat.com>");
4061 MODULE_LICENSE("GPL");
4062