xref: /linux/drivers/md/dm-raid.c (revision bf070bb0e6c62ba3075db0a666763ba52c677102)
1 /*
2  * Copyright (C) 2010-2011 Neil Brown
3  * Copyright (C) 2010-2017 Red Hat, Inc. All rights reserved.
4  *
5  * This file is released under the GPL.
6  */
7 
8 #include <linux/slab.h>
9 #include <linux/module.h>
10 
11 #include "md.h"
12 #include "raid1.h"
13 #include "raid5.h"
14 #include "raid10.h"
15 #include "md-bitmap.h"
16 
17 #include <linux/device-mapper.h>
18 
19 #define DM_MSG_PREFIX "raid"
20 #define	MAX_RAID_DEVICES	253 /* md-raid kernel limit */
21 
22 /*
23  * Minimum sectors of free reshape space per raid device
24  */
25 #define	MIN_FREE_RESHAPE_SPACE to_sector(4*4096)
26 
27 /*
28  * Minimum journal space 4 MiB in sectors.
29  */
30 #define	MIN_RAID456_JOURNAL_SPACE (4*2048)
31 
32 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 #define RESUME_STAY_FROZEN_FLAGS (CTR_FLAG_DELTA_DISKS | CTR_FLAG_DATA_OFFSET)
109 
110 /*
111  * Definitions of various constructor flags to
112  * be used in checks of valid / invalid flags
113  * per raid level.
114  */
115 /* Define all any sync flags */
116 #define	CTR_FLAGS_ANY_SYNC		(CTR_FLAG_SYNC | CTR_FLAG_NOSYNC)
117 
118 /* Define flags for options without argument (e.g. 'nosync') */
119 #define	CTR_FLAG_OPTIONS_NO_ARGS	(CTR_FLAGS_ANY_SYNC | \
120 					 CTR_FLAG_RAID10_USE_NEAR_SETS)
121 
122 /* Define flags for options with one argument (e.g. 'delta_disks +2') */
123 #define CTR_FLAG_OPTIONS_ONE_ARG (CTR_FLAG_REBUILD | \
124 				  CTR_FLAG_WRITE_MOSTLY | \
125 				  CTR_FLAG_DAEMON_SLEEP | \
126 				  CTR_FLAG_MIN_RECOVERY_RATE | \
127 				  CTR_FLAG_MAX_RECOVERY_RATE | \
128 				  CTR_FLAG_MAX_WRITE_BEHIND | \
129 				  CTR_FLAG_STRIPE_CACHE | \
130 				  CTR_FLAG_REGION_SIZE | \
131 				  CTR_FLAG_RAID10_COPIES | \
132 				  CTR_FLAG_RAID10_FORMAT | \
133 				  CTR_FLAG_DELTA_DISKS | \
134 				  CTR_FLAG_DATA_OFFSET)
135 
136 /* Valid options definitions per raid level... */
137 
138 /* "raid0" does only accept data offset */
139 #define RAID0_VALID_FLAGS	(CTR_FLAG_DATA_OFFSET)
140 
141 /* "raid1" does not accept stripe cache, data offset, delta_disks or any raid10 options */
142 #define RAID1_VALID_FLAGS	(CTR_FLAGS_ANY_SYNC | \
143 				 CTR_FLAG_REBUILD | \
144 				 CTR_FLAG_WRITE_MOSTLY | \
145 				 CTR_FLAG_DAEMON_SLEEP | \
146 				 CTR_FLAG_MIN_RECOVERY_RATE | \
147 				 CTR_FLAG_MAX_RECOVERY_RATE | \
148 				 CTR_FLAG_MAX_WRITE_BEHIND | \
149 				 CTR_FLAG_REGION_SIZE | \
150 				 CTR_FLAG_DELTA_DISKS | \
151 				 CTR_FLAG_DATA_OFFSET)
152 
153 /* "raid10" does not accept any raid1 or stripe cache options */
154 #define RAID10_VALID_FLAGS	(CTR_FLAGS_ANY_SYNC | \
155 				 CTR_FLAG_REBUILD | \
156 				 CTR_FLAG_DAEMON_SLEEP | \
157 				 CTR_FLAG_MIN_RECOVERY_RATE | \
158 				 CTR_FLAG_MAX_RECOVERY_RATE | \
159 				 CTR_FLAG_REGION_SIZE | \
160 				 CTR_FLAG_RAID10_COPIES | \
161 				 CTR_FLAG_RAID10_FORMAT | \
162 				 CTR_FLAG_DELTA_DISKS | \
163 				 CTR_FLAG_DATA_OFFSET | \
164 				 CTR_FLAG_RAID10_USE_NEAR_SETS)
165 
166 /*
167  * "raid4/5/6" do not accept any raid1 or raid10 specific options
168  *
169  * "raid6" does not accept "nosync", because it is not guaranteed
170  * that both parity and q-syndrome are being written properly with
171  * any writes
172  */
173 #define RAID45_VALID_FLAGS	(CTR_FLAGS_ANY_SYNC | \
174 				 CTR_FLAG_REBUILD | \
175 				 CTR_FLAG_DAEMON_SLEEP | \
176 				 CTR_FLAG_MIN_RECOVERY_RATE | \
177 				 CTR_FLAG_MAX_RECOVERY_RATE | \
178 				 CTR_FLAG_STRIPE_CACHE | \
179 				 CTR_FLAG_REGION_SIZE | \
180 				 CTR_FLAG_DELTA_DISKS | \
181 				 CTR_FLAG_DATA_OFFSET | \
182 				 CTR_FLAG_JOURNAL_DEV | \
183 				 CTR_FLAG_JOURNAL_MODE)
184 
185 #define RAID6_VALID_FLAGS	(CTR_FLAG_SYNC | \
186 				 CTR_FLAG_REBUILD | \
187 				 CTR_FLAG_DAEMON_SLEEP | \
188 				 CTR_FLAG_MIN_RECOVERY_RATE | \
189 				 CTR_FLAG_MAX_RECOVERY_RATE | \
190 				 CTR_FLAG_STRIPE_CACHE | \
191 				 CTR_FLAG_REGION_SIZE | \
192 				 CTR_FLAG_DELTA_DISKS | \
193 				 CTR_FLAG_DATA_OFFSET | \
194 				 CTR_FLAG_JOURNAL_DEV | \
195 				 CTR_FLAG_JOURNAL_MODE)
196 /* ...valid options definitions per raid level */
197 
198 /*
199  * Flags for rs->runtime_flags field
200  * (RT_FLAG prefix meaning "runtime flag")
201  *
202  * These are all internal and used to define runtime state,
203  * e.g. to prevent another resume from preresume processing
204  * the raid set all over again.
205  */
206 #define RT_FLAG_RS_PRERESUMED		0
207 #define RT_FLAG_RS_RESUMED		1
208 #define RT_FLAG_RS_BITMAP_LOADED	2
209 #define RT_FLAG_UPDATE_SBS		3
210 #define RT_FLAG_RESHAPE_RS		4
211 #define RT_FLAG_RS_SUSPENDED		5
212 
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 bitmap_loaded;
229 	uint32_t stripe_cache_entries;
230 	unsigned long ctr_flags;
231 	unsigned long runtime_flags;
232 
233 	uint64_t rebuild_disks[DISKS_ARRAY_ELEMS];
234 
235 	int raid_disks;
236 	int delta_disks;
237 	int data_offset;
238 	int raid10_copies;
239 	int requested_bitmap_chunk_sectors;
240 
241 	struct mddev md;
242 	struct raid_type *raid_type;
243 	struct dm_target_callbacks callbacks;
244 
245 	/* Optional raid4/5/6 journal device */
246 	struct journal_dev {
247 		struct dm_dev *dev;
248 		struct md_rdev rdev;
249 		int mode;
250 	} journal_dev;
251 
252 	struct raid_dev dev[0];
253 };
254 
255 static void rs_config_backup(struct raid_set *rs, struct rs_layout *l)
256 {
257 	struct mddev *mddev = &rs->md;
258 
259 	l->new_level = mddev->new_level;
260 	l->new_layout = mddev->new_layout;
261 	l->new_chunk_sectors = mddev->new_chunk_sectors;
262 }
263 
264 static void rs_config_restore(struct raid_set *rs, struct rs_layout *l)
265 {
266 	struct mddev *mddev = &rs->md;
267 
268 	mddev->new_level = l->new_level;
269 	mddev->new_layout = l->new_layout;
270 	mddev->new_chunk_sectors = l->new_chunk_sectors;
271 }
272 
273 /* raid10 algorithms (i.e. formats) */
274 #define	ALGORITHM_RAID10_DEFAULT	0
275 #define	ALGORITHM_RAID10_NEAR		1
276 #define	ALGORITHM_RAID10_OFFSET		2
277 #define	ALGORITHM_RAID10_FAR		3
278 
279 /* Supported raid types and properties. */
280 static struct raid_type {
281 	const char *name;		/* RAID algorithm. */
282 	const char *descr;		/* Descriptor text for logging. */
283 	const unsigned int parity_devs;	/* # of parity devices. */
284 	const unsigned int minimal_devs;/* minimal # of devices in set. */
285 	const unsigned int level;	/* RAID level. */
286 	const unsigned int algorithm;	/* RAID algorithm. */
287 } raid_types[] = {
288 	{"raid0",	  "raid0 (striping)",			    0, 2, 0,  0 /* NONE */},
289 	{"raid1",	  "raid1 (mirroring)",			    0, 2, 1,  0 /* NONE */},
290 	{"raid10_far",	  "raid10 far (striped mirrors)",	    0, 2, 10, ALGORITHM_RAID10_FAR},
291 	{"raid10_offset", "raid10 offset (striped mirrors)",	    0, 2, 10, ALGORITHM_RAID10_OFFSET},
292 	{"raid10_near",	  "raid10 near (striped mirrors)",	    0, 2, 10, ALGORITHM_RAID10_NEAR},
293 	{"raid10",	  "raid10 (striped mirrors)",		    0, 2, 10, ALGORITHM_RAID10_DEFAULT},
294 	{"raid4",	  "raid4 (dedicated first parity disk)",    1, 2, 5,  ALGORITHM_PARITY_0}, /* raid4 layout = raid5_0 */
295 	{"raid5_n",	  "raid5 (dedicated last parity disk)",	    1, 2, 5,  ALGORITHM_PARITY_N},
296 	{"raid5_ls",	  "raid5 (left symmetric)",		    1, 2, 5,  ALGORITHM_LEFT_SYMMETRIC},
297 	{"raid5_rs",	  "raid5 (right symmetric)",		    1, 2, 5,  ALGORITHM_RIGHT_SYMMETRIC},
298 	{"raid5_la",	  "raid5 (left asymmetric)",		    1, 2, 5,  ALGORITHM_LEFT_ASYMMETRIC},
299 	{"raid5_ra",	  "raid5 (right asymmetric)",		    1, 2, 5,  ALGORITHM_RIGHT_ASYMMETRIC},
300 	{"raid6_zr",	  "raid6 (zero restart)",		    2, 4, 6,  ALGORITHM_ROTATING_ZERO_RESTART},
301 	{"raid6_nr",	  "raid6 (N restart)",			    2, 4, 6,  ALGORITHM_ROTATING_N_RESTART},
302 	{"raid6_nc",	  "raid6 (N continue)",			    2, 4, 6,  ALGORITHM_ROTATING_N_CONTINUE},
303 	{"raid6_n_6",	  "raid6 (dedicated parity/Q n/6)",	    2, 4, 6,  ALGORITHM_PARITY_N_6},
304 	{"raid6_ls_6",	  "raid6 (left symmetric dedicated Q 6)",   2, 4, 6,  ALGORITHM_LEFT_SYMMETRIC_6},
305 	{"raid6_rs_6",	  "raid6 (right symmetric dedicated Q 6)",  2, 4, 6,  ALGORITHM_RIGHT_SYMMETRIC_6},
306 	{"raid6_la_6",	  "raid6 (left asymmetric dedicated Q 6)",  2, 4, 6,  ALGORITHM_LEFT_ASYMMETRIC_6},
307 	{"raid6_ra_6",	  "raid6 (right asymmetric dedicated Q 6)", 2, 4, 6,  ALGORITHM_RIGHT_ASYMMETRIC_6}
308 };
309 
310 /* True, if @v is in inclusive range [@min, @max] */
311 static bool __within_range(long v, long min, long max)
312 {
313 	return v >= min && v <= max;
314 }
315 
316 /* All table line arguments are defined here */
317 static struct arg_name_flag {
318 	const unsigned long flag;
319 	const char *name;
320 } __arg_name_flags[] = {
321 	{ CTR_FLAG_SYNC, "sync"},
322 	{ CTR_FLAG_NOSYNC, "nosync"},
323 	{ CTR_FLAG_REBUILD, "rebuild"},
324 	{ CTR_FLAG_DAEMON_SLEEP, "daemon_sleep"},
325 	{ CTR_FLAG_MIN_RECOVERY_RATE, "min_recovery_rate"},
326 	{ CTR_FLAG_MAX_RECOVERY_RATE, "max_recovery_rate"},
327 	{ CTR_FLAG_MAX_WRITE_BEHIND, "max_write_behind"},
328 	{ CTR_FLAG_WRITE_MOSTLY, "write_mostly"},
329 	{ CTR_FLAG_STRIPE_CACHE, "stripe_cache"},
330 	{ CTR_FLAG_REGION_SIZE, "region_size"},
331 	{ CTR_FLAG_RAID10_COPIES, "raid10_copies"},
332 	{ CTR_FLAG_RAID10_FORMAT, "raid10_format"},
333 	{ CTR_FLAG_DATA_OFFSET, "data_offset"},
334 	{ CTR_FLAG_DELTA_DISKS, "delta_disks"},
335 	{ CTR_FLAG_RAID10_USE_NEAR_SETS, "raid10_use_near_sets"},
336 	{ CTR_FLAG_JOURNAL_DEV, "journal_dev" },
337 	{ CTR_FLAG_JOURNAL_MODE, "journal_mode" },
338 };
339 
340 /* Return argument name string for given @flag */
341 static const char *dm_raid_arg_name_by_flag(const uint32_t flag)
342 {
343 	if (hweight32(flag) == 1) {
344 		struct arg_name_flag *anf = __arg_name_flags + ARRAY_SIZE(__arg_name_flags);
345 
346 		while (anf-- > __arg_name_flags)
347 			if (flag & anf->flag)
348 				return anf->name;
349 
350 	} else
351 		DMERR("%s called with more than one flag!", __func__);
352 
353 	return NULL;
354 }
355 
356 /* Define correlation of raid456 journal cache modes and dm-raid target line parameters */
357 static struct {
358 	const int mode;
359 	const char *param;
360 } _raid456_journal_mode[] = {
361 	{ R5C_JOURNAL_MODE_WRITE_THROUGH , "writethrough" },
362 	{ R5C_JOURNAL_MODE_WRITE_BACK    , "writeback" }
363 };
364 
365 /* Return MD raid4/5/6 journal mode for dm @journal_mode one */
366 static int dm_raid_journal_mode_to_md(const char *mode)
367 {
368 	int m = ARRAY_SIZE(_raid456_journal_mode);
369 
370 	while (m--)
371 		if (!strcasecmp(mode, _raid456_journal_mode[m].param))
372 			return _raid456_journal_mode[m].mode;
373 
374 	return -EINVAL;
375 }
376 
377 /* Return dm-raid raid4/5/6 journal mode string for @mode */
378 static const char *md_journal_mode_to_dm_raid(const int mode)
379 {
380 	int m = ARRAY_SIZE(_raid456_journal_mode);
381 
382 	while (m--)
383 		if (mode == _raid456_journal_mode[m].mode)
384 			return _raid456_journal_mode[m].param;
385 
386 	return "unknown";
387 }
388 
389 /*
390  * Bool helpers to test for various raid levels of a raid set.
391  * It's level as reported by the superblock rather than
392  * the requested raid_type passed to the constructor.
393  */
394 /* Return true, if raid set in @rs is raid0 */
395 static bool rs_is_raid0(struct raid_set *rs)
396 {
397 	return !rs->md.level;
398 }
399 
400 /* Return true, if raid set in @rs is raid1 */
401 static bool rs_is_raid1(struct raid_set *rs)
402 {
403 	return rs->md.level == 1;
404 }
405 
406 /* Return true, if raid set in @rs is raid10 */
407 static bool rs_is_raid10(struct raid_set *rs)
408 {
409 	return rs->md.level == 10;
410 }
411 
412 /* Return true, if raid set in @rs is level 6 */
413 static bool rs_is_raid6(struct raid_set *rs)
414 {
415 	return rs->md.level == 6;
416 }
417 
418 /* Return true, if raid set in @rs is level 4, 5 or 6 */
419 static bool rs_is_raid456(struct raid_set *rs)
420 {
421 	return __within_range(rs->md.level, 4, 6);
422 }
423 
424 /* Return true, if raid set in @rs is reshapable */
425 static bool __is_raid10_far(int layout);
426 static bool rs_is_reshapable(struct raid_set *rs)
427 {
428 	return rs_is_raid456(rs) ||
429 	       (rs_is_raid10(rs) && !__is_raid10_far(rs->md.new_layout));
430 }
431 
432 /* Return true, if raid set in @rs is recovering */
433 static bool rs_is_recovering(struct raid_set *rs)
434 {
435 	return rs->md.recovery_cp < rs->md.dev_sectors;
436 }
437 
438 /* Return true, if raid set in @rs is reshaping */
439 static bool rs_is_reshaping(struct raid_set *rs)
440 {
441 	return rs->md.reshape_position != MaxSector;
442 }
443 
444 /*
445  * bool helpers to test for various raid levels of a raid type @rt
446  */
447 
448 /* Return true, if raid type in @rt is raid0 */
449 static bool rt_is_raid0(struct raid_type *rt)
450 {
451 	return !rt->level;
452 }
453 
454 /* Return true, if raid type in @rt is raid1 */
455 static bool rt_is_raid1(struct raid_type *rt)
456 {
457 	return rt->level == 1;
458 }
459 
460 /* Return true, if raid type in @rt is raid10 */
461 static bool rt_is_raid10(struct raid_type *rt)
462 {
463 	return rt->level == 10;
464 }
465 
466 /* Return true, if raid type in @rt is raid4/5 */
467 static bool rt_is_raid45(struct raid_type *rt)
468 {
469 	return __within_range(rt->level, 4, 5);
470 }
471 
472 /* Return true, if raid type in @rt is raid6 */
473 static bool rt_is_raid6(struct raid_type *rt)
474 {
475 	return rt->level == 6;
476 }
477 
478 /* Return true, if raid type in @rt is raid4/5/6 */
479 static bool rt_is_raid456(struct raid_type *rt)
480 {
481 	return __within_range(rt->level, 4, 6);
482 }
483 /* END: raid level bools */
484 
485 /* Return valid ctr flags for the raid level of @rs */
486 static unsigned long __valid_flags(struct raid_set *rs)
487 {
488 	if (rt_is_raid0(rs->raid_type))
489 		return RAID0_VALID_FLAGS;
490 	else if (rt_is_raid1(rs->raid_type))
491 		return RAID1_VALID_FLAGS;
492 	else if (rt_is_raid10(rs->raid_type))
493 		return RAID10_VALID_FLAGS;
494 	else if (rt_is_raid45(rs->raid_type))
495 		return RAID45_VALID_FLAGS;
496 	else if (rt_is_raid6(rs->raid_type))
497 		return RAID6_VALID_FLAGS;
498 
499 	return 0;
500 }
501 
502 /*
503  * Check for valid flags set on @rs
504  *
505  * Has to be called after parsing of the ctr flags!
506  */
507 static int rs_check_for_valid_flags(struct raid_set *rs)
508 {
509 	if (rs->ctr_flags & ~__valid_flags(rs)) {
510 		rs->ti->error = "Invalid flags combination";
511 		return -EINVAL;
512 	}
513 
514 	return 0;
515 }
516 
517 /* MD raid10 bit definitions and helpers */
518 #define RAID10_OFFSET			(1 << 16) /* stripes with data copies area adjacent on devices */
519 #define RAID10_BROCKEN_USE_FAR_SETS	(1 << 17) /* Broken in raid10.c: use sets instead of whole stripe rotation */
520 #define RAID10_USE_FAR_SETS		(1 << 18) /* Use sets instead of whole stripe rotation */
521 #define RAID10_FAR_COPIES_SHIFT		8	  /* raid10 # far copies shift (2nd byte of layout) */
522 
523 /* Return md raid10 near copies for @layout */
524 static unsigned int __raid10_near_copies(int layout)
525 {
526 	return layout & 0xFF;
527 }
528 
529 /* Return md raid10 far copies for @layout */
530 static unsigned int __raid10_far_copies(int layout)
531 {
532 	return __raid10_near_copies(layout >> RAID10_FAR_COPIES_SHIFT);
533 }
534 
535 /* Return true if md raid10 offset for @layout */
536 static bool __is_raid10_offset(int layout)
537 {
538 	return !!(layout & RAID10_OFFSET);
539 }
540 
541 /* Return true if md raid10 near for @layout */
542 static bool __is_raid10_near(int layout)
543 {
544 	return !__is_raid10_offset(layout) && __raid10_near_copies(layout) > 1;
545 }
546 
547 /* Return true if md raid10 far for @layout */
548 static bool __is_raid10_far(int layout)
549 {
550 	return !__is_raid10_offset(layout) && __raid10_far_copies(layout) > 1;
551 }
552 
553 /* Return md raid10 layout string for @layout */
554 static const char *raid10_md_layout_to_format(int layout)
555 {
556 	/*
557 	 * Bit 16 stands for "offset"
558 	 * (i.e. adjacent stripes hold copies)
559 	 *
560 	 * Refer to MD's raid10.c for details
561 	 */
562 	if (__is_raid10_offset(layout))
563 		return "offset";
564 
565 	if (__raid10_near_copies(layout) > 1)
566 		return "near";
567 
568 	if (__raid10_far_copies(layout) > 1)
569 		return "far";
570 
571 	return "unknown";
572 }
573 
574 /* Return md raid10 algorithm for @name */
575 static int raid10_name_to_format(const char *name)
576 {
577 	if (!strcasecmp(name, "near"))
578 		return ALGORITHM_RAID10_NEAR;
579 	else if (!strcasecmp(name, "offset"))
580 		return ALGORITHM_RAID10_OFFSET;
581 	else if (!strcasecmp(name, "far"))
582 		return ALGORITHM_RAID10_FAR;
583 
584 	return -EINVAL;
585 }
586 
587 /* Return md raid10 copies for @layout */
588 static unsigned int raid10_md_layout_to_copies(int layout)
589 {
590 	return max(__raid10_near_copies(layout), __raid10_far_copies(layout));
591 }
592 
593 /* Return md raid10 format id for @format string */
594 static int raid10_format_to_md_layout(struct raid_set *rs,
595 				      unsigned int algorithm,
596 				      unsigned int copies)
597 {
598 	unsigned int n = 1, f = 1, r = 0;
599 
600 	/*
601 	 * MD resilienece flaw:
602 	 *
603 	 * enabling use_far_sets for far/offset formats causes copies
604 	 * to be colocated on the same devs together with their origins!
605 	 *
606 	 * -> disable it for now in the definition above
607 	 */
608 	if (algorithm == ALGORITHM_RAID10_DEFAULT ||
609 	    algorithm == ALGORITHM_RAID10_NEAR)
610 		n = copies;
611 
612 	else if (algorithm == ALGORITHM_RAID10_OFFSET) {
613 		f = copies;
614 		r = RAID10_OFFSET;
615 		if (!test_bit(__CTR_FLAG_RAID10_USE_NEAR_SETS, &rs->ctr_flags))
616 			r |= RAID10_USE_FAR_SETS;
617 
618 	} else if (algorithm == ALGORITHM_RAID10_FAR) {
619 		f = copies;
620 		r = !RAID10_OFFSET;
621 		if (!test_bit(__CTR_FLAG_RAID10_USE_NEAR_SETS, &rs->ctr_flags))
622 			r |= RAID10_USE_FAR_SETS;
623 
624 	} else
625 		return -EINVAL;
626 
627 	return r | (f << RAID10_FAR_COPIES_SHIFT) | n;
628 }
629 /* END: MD raid10 bit definitions and helpers */
630 
631 /* Check for any of the raid10 algorithms */
632 static bool __got_raid10(struct raid_type *rtp, const int layout)
633 {
634 	if (rtp->level == 10) {
635 		switch (rtp->algorithm) {
636 		case ALGORITHM_RAID10_DEFAULT:
637 		case ALGORITHM_RAID10_NEAR:
638 			return __is_raid10_near(layout);
639 		case ALGORITHM_RAID10_OFFSET:
640 			return __is_raid10_offset(layout);
641 		case ALGORITHM_RAID10_FAR:
642 			return __is_raid10_far(layout);
643 		default:
644 			break;
645 		}
646 	}
647 
648 	return false;
649 }
650 
651 /* Return raid_type for @name */
652 static struct raid_type *get_raid_type(const char *name)
653 {
654 	struct raid_type *rtp = raid_types + ARRAY_SIZE(raid_types);
655 
656 	while (rtp-- > raid_types)
657 		if (!strcasecmp(rtp->name, name))
658 			return rtp;
659 
660 	return NULL;
661 }
662 
663 /* Return raid_type for @name based derived from @level and @layout */
664 static struct raid_type *get_raid_type_by_ll(const int level, const int layout)
665 {
666 	struct raid_type *rtp = raid_types + ARRAY_SIZE(raid_types);
667 
668 	while (rtp-- > raid_types) {
669 		/* RAID10 special checks based on @layout flags/properties */
670 		if (rtp->level == level &&
671 		    (__got_raid10(rtp, layout) || rtp->algorithm == layout))
672 			return rtp;
673 	}
674 
675 	return NULL;
676 }
677 
678 /*
679  * Conditionally change bdev capacity of @rs
680  * in case of a disk add/remove reshape
681  */
682 static void rs_set_capacity(struct raid_set *rs)
683 {
684 	struct mddev *mddev = &rs->md;
685 	struct md_rdev *rdev;
686 	struct gendisk *gendisk = dm_disk(dm_table_get_md(rs->ti->table));
687 
688 	/*
689 	 * raid10 sets rdev->sector to the device size, which
690 	 * is unintended in case of out-of-place reshaping
691 	 */
692 	rdev_for_each(rdev, mddev)
693 		if (!test_bit(Journal, &rdev->flags))
694 			rdev->sectors = mddev->dev_sectors;
695 
696 	set_capacity(gendisk, mddev->array_sectors);
697 	revalidate_disk(gendisk);
698 }
699 
700 /*
701  * Set the mddev properties in @rs to the current
702  * ones retrieved from the freshest superblock
703  */
704 static void rs_set_cur(struct raid_set *rs)
705 {
706 	struct mddev *mddev = &rs->md;
707 
708 	mddev->new_level = mddev->level;
709 	mddev->new_layout = mddev->layout;
710 	mddev->new_chunk_sectors = mddev->chunk_sectors;
711 }
712 
713 /*
714  * Set the mddev properties in @rs to the new
715  * ones requested by the ctr
716  */
717 static void rs_set_new(struct raid_set *rs)
718 {
719 	struct mddev *mddev = &rs->md;
720 
721 	mddev->level = mddev->new_level;
722 	mddev->layout = mddev->new_layout;
723 	mddev->chunk_sectors = mddev->new_chunk_sectors;
724 	mddev->raid_disks = rs->raid_disks;
725 	mddev->delta_disks = 0;
726 }
727 
728 static struct raid_set *raid_set_alloc(struct dm_target *ti, struct raid_type *raid_type,
729 				       unsigned int raid_devs)
730 {
731 	unsigned int i;
732 	struct raid_set *rs;
733 
734 	if (raid_devs <= raid_type->parity_devs) {
735 		ti->error = "Insufficient number of devices";
736 		return ERR_PTR(-EINVAL);
737 	}
738 
739 	rs = kzalloc(sizeof(*rs) + raid_devs * sizeof(rs->dev[0]), GFP_KERNEL);
740 	if (!rs) {
741 		ti->error = "Cannot allocate raid context";
742 		return ERR_PTR(-ENOMEM);
743 	}
744 
745 	mddev_init(&rs->md);
746 
747 	rs->raid_disks = raid_devs;
748 	rs->delta_disks = 0;
749 
750 	rs->ti = ti;
751 	rs->raid_type = raid_type;
752 	rs->stripe_cache_entries = 256;
753 	rs->md.raid_disks = raid_devs;
754 	rs->md.level = raid_type->level;
755 	rs->md.new_level = rs->md.level;
756 	rs->md.layout = raid_type->algorithm;
757 	rs->md.new_layout = rs->md.layout;
758 	rs->md.delta_disks = 0;
759 	rs->md.recovery_cp = MaxSector;
760 
761 	for (i = 0; i < raid_devs; i++)
762 		md_rdev_init(&rs->dev[i].rdev);
763 
764 	/*
765 	 * Remaining items to be initialized by further RAID params:
766 	 *  rs->md.persistent
767 	 *  rs->md.external
768 	 *  rs->md.chunk_sectors
769 	 *  rs->md.new_chunk_sectors
770 	 *  rs->md.dev_sectors
771 	 */
772 
773 	return rs;
774 }
775 
776 static void raid_set_free(struct raid_set *rs)
777 {
778 	int i;
779 
780 	if (rs->journal_dev.dev) {
781 		md_rdev_clear(&rs->journal_dev.rdev);
782 		dm_put_device(rs->ti, rs->journal_dev.dev);
783 	}
784 
785 	for (i = 0; i < rs->raid_disks; i++) {
786 		if (rs->dev[i].meta_dev)
787 			dm_put_device(rs->ti, rs->dev[i].meta_dev);
788 		md_rdev_clear(&rs->dev[i].rdev);
789 		if (rs->dev[i].data_dev)
790 			dm_put_device(rs->ti, rs->dev[i].data_dev);
791 	}
792 
793 	kfree(rs);
794 }
795 
796 /*
797  * For every device we have two words
798  *  <meta_dev>: meta device name or '-' if missing
799  *  <data_dev>: data device name or '-' if missing
800  *
801  * The following are permitted:
802  *    - -
803  *    - <data_dev>
804  *    <meta_dev> <data_dev>
805  *
806  * The following is not allowed:
807  *    <meta_dev> -
808  *
809  * This code parses those words.  If there is a failure,
810  * the caller must use raid_set_free() to unwind the operations.
811  */
812 static int parse_dev_params(struct raid_set *rs, struct dm_arg_set *as)
813 {
814 	int i;
815 	int rebuild = 0;
816 	int metadata_available = 0;
817 	int r = 0;
818 	const char *arg;
819 
820 	/* Put off the number of raid devices argument to get to dev pairs */
821 	arg = dm_shift_arg(as);
822 	if (!arg)
823 		return -EINVAL;
824 
825 	for (i = 0; i < rs->raid_disks; i++) {
826 		rs->dev[i].rdev.raid_disk = i;
827 
828 		rs->dev[i].meta_dev = NULL;
829 		rs->dev[i].data_dev = NULL;
830 
831 		/*
832 		 * There are no offsets initially.
833 		 * Out of place reshape will set them accordingly.
834 		 */
835 		rs->dev[i].rdev.data_offset = 0;
836 		rs->dev[i].rdev.new_data_offset = 0;
837 		rs->dev[i].rdev.mddev = &rs->md;
838 
839 		arg = dm_shift_arg(as);
840 		if (!arg)
841 			return -EINVAL;
842 
843 		if (strcmp(arg, "-")) {
844 			r = dm_get_device(rs->ti, arg, dm_table_get_mode(rs->ti->table),
845 					  &rs->dev[i].meta_dev);
846 			if (r) {
847 				rs->ti->error = "RAID metadata device lookup failure";
848 				return r;
849 			}
850 
851 			rs->dev[i].rdev.sb_page = alloc_page(GFP_KERNEL);
852 			if (!rs->dev[i].rdev.sb_page) {
853 				rs->ti->error = "Failed to allocate superblock page";
854 				return -ENOMEM;
855 			}
856 		}
857 
858 		arg = dm_shift_arg(as);
859 		if (!arg)
860 			return -EINVAL;
861 
862 		if (!strcmp(arg, "-")) {
863 			if (!test_bit(In_sync, &rs->dev[i].rdev.flags) &&
864 			    (!rs->dev[i].rdev.recovery_offset)) {
865 				rs->ti->error = "Drive designated for rebuild not specified";
866 				return -EINVAL;
867 			}
868 
869 			if (rs->dev[i].meta_dev) {
870 				rs->ti->error = "No data device supplied with metadata device";
871 				return -EINVAL;
872 			}
873 
874 			continue;
875 		}
876 
877 		r = dm_get_device(rs->ti, arg, dm_table_get_mode(rs->ti->table),
878 				  &rs->dev[i].data_dev);
879 		if (r) {
880 			rs->ti->error = "RAID device lookup failure";
881 			return r;
882 		}
883 
884 		if (rs->dev[i].meta_dev) {
885 			metadata_available = 1;
886 			rs->dev[i].rdev.meta_bdev = rs->dev[i].meta_dev->bdev;
887 		}
888 		rs->dev[i].rdev.bdev = rs->dev[i].data_dev->bdev;
889 		list_add_tail(&rs->dev[i].rdev.same_set, &rs->md.disks);
890 		if (!test_bit(In_sync, &rs->dev[i].rdev.flags))
891 			rebuild++;
892 	}
893 
894 	if (rs->journal_dev.dev)
895 		list_add_tail(&rs->journal_dev.rdev.same_set, &rs->md.disks);
896 
897 	if (metadata_available) {
898 		rs->md.external = 0;
899 		rs->md.persistent = 1;
900 		rs->md.major_version = 2;
901 	} else if (rebuild && !rs->md.recovery_cp) {
902 		/*
903 		 * Without metadata, we will not be able to tell if the array
904 		 * is in-sync or not - we must assume it is not.  Therefore,
905 		 * it is impossible to rebuild a drive.
906 		 *
907 		 * Even if there is metadata, the on-disk information may
908 		 * indicate that the array is not in-sync and it will then
909 		 * fail at that time.
910 		 *
911 		 * User could specify 'nosync' option if desperate.
912 		 */
913 		rs->ti->error = "Unable to rebuild drive while array is not in-sync";
914 		return -EINVAL;
915 	}
916 
917 	return 0;
918 }
919 
920 /*
921  * validate_region_size
922  * @rs
923  * @region_size:  region size in sectors.  If 0, pick a size (4MiB default).
924  *
925  * Set rs->md.bitmap_info.chunksize (which really refers to 'region size').
926  * Ensure that (ti->len/region_size < 2^21) - required by MD bitmap.
927  *
928  * Returns: 0 on success, -EINVAL on failure.
929  */
930 static int validate_region_size(struct raid_set *rs, unsigned long region_size)
931 {
932 	unsigned long min_region_size = rs->ti->len / (1 << 21);
933 
934 	if (rs_is_raid0(rs))
935 		return 0;
936 
937 	if (!region_size) {
938 		/*
939 		 * Choose a reasonable default.	 All figures in sectors.
940 		 */
941 		if (min_region_size > (1 << 13)) {
942 			/* If not a power of 2, make it the next power of 2 */
943 			region_size = roundup_pow_of_two(min_region_size);
944 			DMINFO("Choosing default region size of %lu sectors",
945 			       region_size);
946 		} else {
947 			DMINFO("Choosing default region size of 4MiB");
948 			region_size = 1 << 13; /* sectors */
949 		}
950 	} else {
951 		/*
952 		 * Validate user-supplied value.
953 		 */
954 		if (region_size > rs->ti->len) {
955 			rs->ti->error = "Supplied region size is too large";
956 			return -EINVAL;
957 		}
958 
959 		if (region_size < min_region_size) {
960 			DMERR("Supplied region_size (%lu sectors) below minimum (%lu)",
961 			      region_size, min_region_size);
962 			rs->ti->error = "Supplied region size is too small";
963 			return -EINVAL;
964 		}
965 
966 		if (!is_power_of_2(region_size)) {
967 			rs->ti->error = "Region size is not a power of 2";
968 			return -EINVAL;
969 		}
970 
971 		if (region_size < rs->md.chunk_sectors) {
972 			rs->ti->error = "Region size is smaller than the chunk size";
973 			return -EINVAL;
974 		}
975 	}
976 
977 	/*
978 	 * Convert sectors to bytes.
979 	 */
980 	rs->md.bitmap_info.chunksize = to_bytes(region_size);
981 
982 	return 0;
983 }
984 
985 /*
986  * validate_raid_redundancy
987  * @rs
988  *
989  * Determine if there are enough devices in the array that haven't
990  * failed (or are being rebuilt) to form a usable array.
991  *
992  * Returns: 0 on success, -EINVAL on failure.
993  */
994 static int validate_raid_redundancy(struct raid_set *rs)
995 {
996 	unsigned int i, rebuild_cnt = 0;
997 	unsigned int rebuilds_per_group = 0, copies;
998 	unsigned int group_size, last_group_start;
999 
1000 	for (i = 0; i < rs->md.raid_disks; i++)
1001 		if (!test_bit(In_sync, &rs->dev[i].rdev.flags) ||
1002 		    !rs->dev[i].rdev.sb_page)
1003 			rebuild_cnt++;
1004 
1005 	switch (rs->raid_type->level) {
1006 	case 0:
1007 		break;
1008 	case 1:
1009 		if (rebuild_cnt >= rs->md.raid_disks)
1010 			goto too_many;
1011 		break;
1012 	case 4:
1013 	case 5:
1014 	case 6:
1015 		if (rebuild_cnt > rs->raid_type->parity_devs)
1016 			goto too_many;
1017 		break;
1018 	case 10:
1019 		copies = raid10_md_layout_to_copies(rs->md.new_layout);
1020 		if (rebuild_cnt < copies)
1021 			break;
1022 
1023 		/*
1024 		 * It is possible to have a higher rebuild count for RAID10,
1025 		 * as long as the failed devices occur in different mirror
1026 		 * groups (i.e. different stripes).
1027 		 *
1028 		 * When checking "near" format, make sure no adjacent devices
1029 		 * have failed beyond what can be handled.  In addition to the
1030 		 * simple case where the number of devices is a multiple of the
1031 		 * number of copies, we must also handle cases where the number
1032 		 * of devices is not a multiple of the number of copies.
1033 		 * E.g.	   dev1 dev2 dev3 dev4 dev5
1034 		 *	    A	 A    B	   B	C
1035 		 *	    C	 D    D	   E	E
1036 		 */
1037 		if (__is_raid10_near(rs->md.new_layout)) {
1038 			for (i = 0; i < rs->md.raid_disks; i++) {
1039 				if (!(i % copies))
1040 					rebuilds_per_group = 0;
1041 				if ((!rs->dev[i].rdev.sb_page ||
1042 				    !test_bit(In_sync, &rs->dev[i].rdev.flags)) &&
1043 				    (++rebuilds_per_group >= copies))
1044 					goto too_many;
1045 			}
1046 			break;
1047 		}
1048 
1049 		/*
1050 		 * When checking "far" and "offset" formats, we need to ensure
1051 		 * that the device that holds its copy is not also dead or
1052 		 * being rebuilt.  (Note that "far" and "offset" formats only
1053 		 * support two copies right now.  These formats also only ever
1054 		 * use the 'use_far_sets' variant.)
1055 		 *
1056 		 * This check is somewhat complicated by the need to account
1057 		 * for arrays that are not a multiple of (far) copies.	This
1058 		 * results in the need to treat the last (potentially larger)
1059 		 * set differently.
1060 		 */
1061 		group_size = (rs->md.raid_disks / copies);
1062 		last_group_start = (rs->md.raid_disks / group_size) - 1;
1063 		last_group_start *= group_size;
1064 		for (i = 0; i < rs->md.raid_disks; i++) {
1065 			if (!(i % copies) && !(i > last_group_start))
1066 				rebuilds_per_group = 0;
1067 			if ((!rs->dev[i].rdev.sb_page ||
1068 			     !test_bit(In_sync, &rs->dev[i].rdev.flags)) &&
1069 			    (++rebuilds_per_group >= copies))
1070 					goto too_many;
1071 		}
1072 		break;
1073 	default:
1074 		if (rebuild_cnt)
1075 			return -EINVAL;
1076 	}
1077 
1078 	return 0;
1079 
1080 too_many:
1081 	return -EINVAL;
1082 }
1083 
1084 /*
1085  * Possible arguments are...
1086  *	<chunk_size> [optional_args]
1087  *
1088  * Argument definitions
1089  *    <chunk_size>			The number of sectors per disk that
1090  *					will form the "stripe"
1091  *    [[no]sync]			Force or prevent recovery of the
1092  *					entire array
1093  *    [rebuild <idx>]			Rebuild the drive indicated by the index
1094  *    [daemon_sleep <ms>]		Time between bitmap daemon work to
1095  *					clear bits
1096  *    [min_recovery_rate <kB/sec/disk>]	Throttle RAID initialization
1097  *    [max_recovery_rate <kB/sec/disk>]	Throttle RAID initialization
1098  *    [write_mostly <idx>]		Indicate a write mostly drive via index
1099  *    [max_write_behind <sectors>]	See '-write-behind=' (man mdadm)
1100  *    [stripe_cache <sectors>]		Stripe cache size for higher RAIDs
1101  *    [region_size <sectors>]		Defines granularity of bitmap
1102  *    [journal_dev <dev>]		raid4/5/6 journaling deviice
1103  *    					(i.e. write hole closing log)
1104  *
1105  * RAID10-only options:
1106  *    [raid10_copies <# copies>]	Number of copies.  (Default: 2)
1107  *    [raid10_format <near|far|offset>] Layout algorithm.  (Default: near)
1108  */
1109 static int parse_raid_params(struct raid_set *rs, struct dm_arg_set *as,
1110 			     unsigned int num_raid_params)
1111 {
1112 	int value, raid10_format = ALGORITHM_RAID10_DEFAULT;
1113 	unsigned int raid10_copies = 2;
1114 	unsigned int i, write_mostly = 0;
1115 	unsigned int region_size = 0;
1116 	sector_t max_io_len;
1117 	const char *arg, *key;
1118 	struct raid_dev *rd;
1119 	struct raid_type *rt = rs->raid_type;
1120 
1121 	arg = dm_shift_arg(as);
1122 	num_raid_params--; /* Account for chunk_size argument */
1123 
1124 	if (kstrtoint(arg, 10, &value) < 0) {
1125 		rs->ti->error = "Bad numerical argument given for chunk_size";
1126 		return -EINVAL;
1127 	}
1128 
1129 	/*
1130 	 * First, parse the in-order required arguments
1131 	 * "chunk_size" is the only argument of this type.
1132 	 */
1133 	if (rt_is_raid1(rt)) {
1134 		if (value)
1135 			DMERR("Ignoring chunk size parameter for RAID 1");
1136 		value = 0;
1137 	} else if (!is_power_of_2(value)) {
1138 		rs->ti->error = "Chunk size must be a power of 2";
1139 		return -EINVAL;
1140 	} else if (value < 8) {
1141 		rs->ti->error = "Chunk size value is too small";
1142 		return -EINVAL;
1143 	}
1144 
1145 	rs->md.new_chunk_sectors = rs->md.chunk_sectors = value;
1146 
1147 	/*
1148 	 * We set each individual device as In_sync with a completed
1149 	 * 'recovery_offset'.  If there has been a device failure or
1150 	 * replacement then one of the following cases applies:
1151 	 *
1152 	 *   1) User specifies 'rebuild'.
1153 	 *	- Device is reset when param is read.
1154 	 *   2) A new device is supplied.
1155 	 *	- No matching superblock found, resets device.
1156 	 *   3) Device failure was transient and returns on reload.
1157 	 *	- Failure noticed, resets device for bitmap replay.
1158 	 *   4) Device hadn't completed recovery after previous failure.
1159 	 *	- Superblock is read and overrides recovery_offset.
1160 	 *
1161 	 * What is found in the superblocks of the devices is always
1162 	 * authoritative, unless 'rebuild' or '[no]sync' was specified.
1163 	 */
1164 	for (i = 0; i < rs->raid_disks; i++) {
1165 		set_bit(In_sync, &rs->dev[i].rdev.flags);
1166 		rs->dev[i].rdev.recovery_offset = MaxSector;
1167 	}
1168 
1169 	/*
1170 	 * Second, parse the unordered optional arguments
1171 	 */
1172 	for (i = 0; i < num_raid_params; i++) {
1173 		key = dm_shift_arg(as);
1174 		if (!key) {
1175 			rs->ti->error = "Not enough raid parameters given";
1176 			return -EINVAL;
1177 		}
1178 
1179 		if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_NOSYNC))) {
1180 			if (test_and_set_bit(__CTR_FLAG_NOSYNC, &rs->ctr_flags)) {
1181 				rs->ti->error = "Only one 'nosync' argument allowed";
1182 				return -EINVAL;
1183 			}
1184 			continue;
1185 		}
1186 		if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_SYNC))) {
1187 			if (test_and_set_bit(__CTR_FLAG_SYNC, &rs->ctr_flags)) {
1188 				rs->ti->error = "Only one 'sync' argument allowed";
1189 				return -EINVAL;
1190 			}
1191 			continue;
1192 		}
1193 		if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_RAID10_USE_NEAR_SETS))) {
1194 			if (test_and_set_bit(__CTR_FLAG_RAID10_USE_NEAR_SETS, &rs->ctr_flags)) {
1195 				rs->ti->error = "Only one 'raid10_use_new_sets' argument allowed";
1196 				return -EINVAL;
1197 			}
1198 			continue;
1199 		}
1200 
1201 		arg = dm_shift_arg(as);
1202 		i++; /* Account for the argument pairs */
1203 		if (!arg) {
1204 			rs->ti->error = "Wrong number of raid parameters given";
1205 			return -EINVAL;
1206 		}
1207 
1208 		/*
1209 		 * Parameters that take a string value are checked here.
1210 		 */
1211 		/* "raid10_format {near|offset|far} */
1212 		if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_RAID10_FORMAT))) {
1213 			if (test_and_set_bit(__CTR_FLAG_RAID10_FORMAT, &rs->ctr_flags)) {
1214 				rs->ti->error = "Only one 'raid10_format' argument pair allowed";
1215 				return -EINVAL;
1216 			}
1217 			if (!rt_is_raid10(rt)) {
1218 				rs->ti->error = "'raid10_format' is an invalid parameter for this RAID type";
1219 				return -EINVAL;
1220 			}
1221 			raid10_format = raid10_name_to_format(arg);
1222 			if (raid10_format < 0) {
1223 				rs->ti->error = "Invalid 'raid10_format' value given";
1224 				return raid10_format;
1225 			}
1226 			continue;
1227 		}
1228 
1229 		/* "journal_dev <dev>" */
1230 		if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_JOURNAL_DEV))) {
1231 			int r;
1232 			struct md_rdev *jdev;
1233 
1234 			if (test_and_set_bit(__CTR_FLAG_JOURNAL_DEV, &rs->ctr_flags)) {
1235 				rs->ti->error = "Only one raid4/5/6 set journaling device allowed";
1236 				return -EINVAL;
1237 			}
1238 			if (!rt_is_raid456(rt)) {
1239 				rs->ti->error = "'journal_dev' is an invalid parameter for this RAID type";
1240 				return -EINVAL;
1241 			}
1242 			r = dm_get_device(rs->ti, arg, dm_table_get_mode(rs->ti->table),
1243 					  &rs->journal_dev.dev);
1244 			if (r) {
1245 				rs->ti->error = "raid4/5/6 journal device lookup failure";
1246 				return r;
1247 			}
1248 			jdev = &rs->journal_dev.rdev;
1249 			md_rdev_init(jdev);
1250 			jdev->mddev = &rs->md;
1251 			jdev->bdev = rs->journal_dev.dev->bdev;
1252 			jdev->sectors = to_sector(i_size_read(jdev->bdev->bd_inode));
1253 			if (jdev->sectors < MIN_RAID456_JOURNAL_SPACE) {
1254 				rs->ti->error = "No space for raid4/5/6 journal";
1255 				return -ENOSPC;
1256 			}
1257 			rs->journal_dev.mode = R5C_JOURNAL_MODE_WRITE_THROUGH;
1258 			set_bit(Journal, &jdev->flags);
1259 			continue;
1260 		}
1261 
1262 		/* "journal_mode <mode>" ("journal_dev" mandatory!) */
1263 		if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_JOURNAL_MODE))) {
1264 			int r;
1265 
1266 			if (!test_bit(__CTR_FLAG_JOURNAL_DEV, &rs->ctr_flags)) {
1267 				rs->ti->error = "raid4/5/6 'journal_mode' is invalid without 'journal_dev'";
1268 				return -EINVAL;
1269 			}
1270 			if (test_and_set_bit(__CTR_FLAG_JOURNAL_MODE, &rs->ctr_flags)) {
1271 				rs->ti->error = "Only one raid4/5/6 'journal_mode' argument allowed";
1272 				return -EINVAL;
1273 			}
1274 			r = dm_raid_journal_mode_to_md(arg);
1275 			if (r < 0) {
1276 				rs->ti->error = "Invalid 'journal_mode' argument";
1277 				return r;
1278 			}
1279 			rs->journal_dev.mode = r;
1280 			continue;
1281 		}
1282 
1283 		/*
1284 		 * Parameters with number values from here on.
1285 		 */
1286 		if (kstrtoint(arg, 10, &value) < 0) {
1287 			rs->ti->error = "Bad numerical argument given in raid params";
1288 			return -EINVAL;
1289 		}
1290 
1291 		if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_REBUILD))) {
1292 			/*
1293 			 * "rebuild" is being passed in by userspace to provide
1294 			 * indexes of replaced devices and to set up additional
1295 			 * devices on raid level takeover.
1296 			 */
1297 			if (!__within_range(value, 0, rs->raid_disks - 1)) {
1298 				rs->ti->error = "Invalid rebuild index given";
1299 				return -EINVAL;
1300 			}
1301 
1302 			if (test_and_set_bit(value, (void *) rs->rebuild_disks)) {
1303 				rs->ti->error = "rebuild for this index already given";
1304 				return -EINVAL;
1305 			}
1306 
1307 			rd = rs->dev + value;
1308 			clear_bit(In_sync, &rd->rdev.flags);
1309 			clear_bit(Faulty, &rd->rdev.flags);
1310 			rd->rdev.recovery_offset = 0;
1311 			set_bit(__CTR_FLAG_REBUILD, &rs->ctr_flags);
1312 		} else if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_WRITE_MOSTLY))) {
1313 			if (!rt_is_raid1(rt)) {
1314 				rs->ti->error = "write_mostly option is only valid for RAID1";
1315 				return -EINVAL;
1316 			}
1317 
1318 			if (!__within_range(value, 0, rs->md.raid_disks - 1)) {
1319 				rs->ti->error = "Invalid write_mostly index given";
1320 				return -EINVAL;
1321 			}
1322 
1323 			write_mostly++;
1324 			set_bit(WriteMostly, &rs->dev[value].rdev.flags);
1325 			set_bit(__CTR_FLAG_WRITE_MOSTLY, &rs->ctr_flags);
1326 		} else if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_MAX_WRITE_BEHIND))) {
1327 			if (!rt_is_raid1(rt)) {
1328 				rs->ti->error = "max_write_behind option is only valid for RAID1";
1329 				return -EINVAL;
1330 			}
1331 
1332 			if (test_and_set_bit(__CTR_FLAG_MAX_WRITE_BEHIND, &rs->ctr_flags)) {
1333 				rs->ti->error = "Only one max_write_behind argument pair allowed";
1334 				return -EINVAL;
1335 			}
1336 
1337 			/*
1338 			 * In device-mapper, we specify things in sectors, but
1339 			 * MD records this value in kB
1340 			 */
1341 			value /= 2;
1342 			if (value > COUNTER_MAX) {
1343 				rs->ti->error = "Max write-behind limit out of range";
1344 				return -EINVAL;
1345 			}
1346 
1347 			rs->md.bitmap_info.max_write_behind = value;
1348 		} else if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_DAEMON_SLEEP))) {
1349 			if (test_and_set_bit(__CTR_FLAG_DAEMON_SLEEP, &rs->ctr_flags)) {
1350 				rs->ti->error = "Only one daemon_sleep argument pair allowed";
1351 				return -EINVAL;
1352 			}
1353 			if (!value || (value > MAX_SCHEDULE_TIMEOUT)) {
1354 				rs->ti->error = "daemon sleep period out of range";
1355 				return -EINVAL;
1356 			}
1357 			rs->md.bitmap_info.daemon_sleep = value;
1358 		} else if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_DATA_OFFSET))) {
1359 			/* Userspace passes new data_offset after having extended the the data image LV */
1360 			if (test_and_set_bit(__CTR_FLAG_DATA_OFFSET, &rs->ctr_flags)) {
1361 				rs->ti->error = "Only one data_offset argument pair allowed";
1362 				return -EINVAL;
1363 			}
1364 			/* Ensure sensible data offset */
1365 			if (value < 0 ||
1366 			    (value && (value < MIN_FREE_RESHAPE_SPACE || value % to_sector(PAGE_SIZE)))) {
1367 				rs->ti->error = "Bogus data_offset value";
1368 				return -EINVAL;
1369 			}
1370 			rs->data_offset = value;
1371 		} else if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_DELTA_DISKS))) {
1372 			/* Define the +/-# of disks to add to/remove from the given raid set */
1373 			if (test_and_set_bit(__CTR_FLAG_DELTA_DISKS, &rs->ctr_flags)) {
1374 				rs->ti->error = "Only one delta_disks argument pair allowed";
1375 				return -EINVAL;
1376 			}
1377 			/* Ensure MAX_RAID_DEVICES and raid type minimal_devs! */
1378 			if (!__within_range(abs(value), 1, MAX_RAID_DEVICES - rt->minimal_devs)) {
1379 				rs->ti->error = "Too many delta_disk requested";
1380 				return -EINVAL;
1381 			}
1382 
1383 			rs->delta_disks = value;
1384 		} else if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_STRIPE_CACHE))) {
1385 			if (test_and_set_bit(__CTR_FLAG_STRIPE_CACHE, &rs->ctr_flags)) {
1386 				rs->ti->error = "Only one stripe_cache argument pair allowed";
1387 				return -EINVAL;
1388 			}
1389 
1390 			if (!rt_is_raid456(rt)) {
1391 				rs->ti->error = "Inappropriate argument: stripe_cache";
1392 				return -EINVAL;
1393 			}
1394 
1395 			rs->stripe_cache_entries = value;
1396 		} else if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_MIN_RECOVERY_RATE))) {
1397 			if (test_and_set_bit(__CTR_FLAG_MIN_RECOVERY_RATE, &rs->ctr_flags)) {
1398 				rs->ti->error = "Only one min_recovery_rate argument pair allowed";
1399 				return -EINVAL;
1400 			}
1401 			if (value > INT_MAX) {
1402 				rs->ti->error = "min_recovery_rate out of range";
1403 				return -EINVAL;
1404 			}
1405 			rs->md.sync_speed_min = (int)value;
1406 		} else if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_MAX_RECOVERY_RATE))) {
1407 			if (test_and_set_bit(__CTR_FLAG_MAX_RECOVERY_RATE, &rs->ctr_flags)) {
1408 				rs->ti->error = "Only one max_recovery_rate argument pair allowed";
1409 				return -EINVAL;
1410 			}
1411 			if (value > INT_MAX) {
1412 				rs->ti->error = "max_recovery_rate out of range";
1413 				return -EINVAL;
1414 			}
1415 			rs->md.sync_speed_max = (int)value;
1416 		} else if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_REGION_SIZE))) {
1417 			if (test_and_set_bit(__CTR_FLAG_REGION_SIZE, &rs->ctr_flags)) {
1418 				rs->ti->error = "Only one region_size argument pair allowed";
1419 				return -EINVAL;
1420 			}
1421 
1422 			region_size = value;
1423 			rs->requested_bitmap_chunk_sectors = value;
1424 		} else if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_RAID10_COPIES))) {
1425 			if (test_and_set_bit(__CTR_FLAG_RAID10_COPIES, &rs->ctr_flags)) {
1426 				rs->ti->error = "Only one raid10_copies argument pair allowed";
1427 				return -EINVAL;
1428 			}
1429 
1430 			if (!__within_range(value, 2, rs->md.raid_disks)) {
1431 				rs->ti->error = "Bad value for 'raid10_copies'";
1432 				return -EINVAL;
1433 			}
1434 
1435 			raid10_copies = value;
1436 		} else {
1437 			DMERR("Unable to parse RAID parameter: %s", key);
1438 			rs->ti->error = "Unable to parse RAID parameter";
1439 			return -EINVAL;
1440 		}
1441 	}
1442 
1443 	if (test_bit(__CTR_FLAG_SYNC, &rs->ctr_flags) &&
1444 	    test_bit(__CTR_FLAG_NOSYNC, &rs->ctr_flags)) {
1445 		rs->ti->error = "sync and nosync are mutually exclusive";
1446 		return -EINVAL;
1447 	}
1448 
1449 	if (test_bit(__CTR_FLAG_REBUILD, &rs->ctr_flags) &&
1450 	    (test_bit(__CTR_FLAG_SYNC, &rs->ctr_flags) ||
1451 	     test_bit(__CTR_FLAG_NOSYNC, &rs->ctr_flags))) {
1452 		rs->ti->error = "sync/nosync and rebuild are mutually exclusive";
1453 		return -EINVAL;
1454 	}
1455 
1456 	if (write_mostly >= rs->md.raid_disks) {
1457 		rs->ti->error = "Can't set all raid1 devices to write_mostly";
1458 		return -EINVAL;
1459 	}
1460 
1461 	if (validate_region_size(rs, region_size))
1462 		return -EINVAL;
1463 
1464 	if (rs->md.chunk_sectors)
1465 		max_io_len = rs->md.chunk_sectors;
1466 	else
1467 		max_io_len = region_size;
1468 
1469 	if (dm_set_target_max_io_len(rs->ti, max_io_len))
1470 		return -EINVAL;
1471 
1472 	if (rt_is_raid10(rt)) {
1473 		if (raid10_copies > rs->md.raid_disks) {
1474 			rs->ti->error = "Not enough devices to satisfy specification";
1475 			return -EINVAL;
1476 		}
1477 
1478 		rs->md.new_layout = raid10_format_to_md_layout(rs, raid10_format, raid10_copies);
1479 		if (rs->md.new_layout < 0) {
1480 			rs->ti->error = "Error getting raid10 format";
1481 			return rs->md.new_layout;
1482 		}
1483 
1484 		rt = get_raid_type_by_ll(10, rs->md.new_layout);
1485 		if (!rt) {
1486 			rs->ti->error = "Failed to recognize new raid10 layout";
1487 			return -EINVAL;
1488 		}
1489 
1490 		if ((rt->algorithm == ALGORITHM_RAID10_DEFAULT ||
1491 		     rt->algorithm == ALGORITHM_RAID10_NEAR) &&
1492 		    test_bit(__CTR_FLAG_RAID10_USE_NEAR_SETS, &rs->ctr_flags)) {
1493 			rs->ti->error = "RAID10 format 'near' and 'raid10_use_near_sets' are incompatible";
1494 			return -EINVAL;
1495 		}
1496 	}
1497 
1498 	rs->raid10_copies = raid10_copies;
1499 
1500 	/* Assume there are no metadata devices until the drives are parsed */
1501 	rs->md.persistent = 0;
1502 	rs->md.external = 1;
1503 
1504 	/* Check, if any invalid ctr arguments have been passed in for the raid level */
1505 	return rs_check_for_valid_flags(rs);
1506 }
1507 
1508 /* Set raid4/5/6 cache size */
1509 static int rs_set_raid456_stripe_cache(struct raid_set *rs)
1510 {
1511 	int r;
1512 	struct r5conf *conf;
1513 	struct mddev *mddev = &rs->md;
1514 	uint32_t min_stripes = max(mddev->chunk_sectors, mddev->new_chunk_sectors) / 2;
1515 	uint32_t nr_stripes = rs->stripe_cache_entries;
1516 
1517 	if (!rt_is_raid456(rs->raid_type)) {
1518 		rs->ti->error = "Inappropriate raid level; cannot change stripe_cache size";
1519 		return -EINVAL;
1520 	}
1521 
1522 	if (nr_stripes < min_stripes) {
1523 		DMINFO("Adjusting requested %u stripe cache entries to %u to suit stripe size",
1524 		       nr_stripes, min_stripes);
1525 		nr_stripes = min_stripes;
1526 	}
1527 
1528 	conf = mddev->private;
1529 	if (!conf) {
1530 		rs->ti->error = "Cannot change stripe_cache size on inactive RAID set";
1531 		return -EINVAL;
1532 	}
1533 
1534 	/* Try setting number of stripes in raid456 stripe cache */
1535 	if (conf->min_nr_stripes != nr_stripes) {
1536 		r = raid5_set_cache_size(mddev, nr_stripes);
1537 		if (r) {
1538 			rs->ti->error = "Failed to set raid4/5/6 stripe cache size";
1539 			return r;
1540 		}
1541 
1542 		DMINFO("%u stripe cache entries", nr_stripes);
1543 	}
1544 
1545 	return 0;
1546 }
1547 
1548 /* Return # of data stripes as kept in mddev as of @rs (i.e. as of superblock) */
1549 static unsigned int mddev_data_stripes(struct raid_set *rs)
1550 {
1551 	return rs->md.raid_disks - rs->raid_type->parity_devs;
1552 }
1553 
1554 /* Return # of data stripes of @rs (i.e. as of ctr) */
1555 static unsigned int rs_data_stripes(struct raid_set *rs)
1556 {
1557 	return rs->raid_disks - rs->raid_type->parity_devs;
1558 }
1559 
1560 /*
1561  * Retrieve rdev->sectors from any valid raid device of @rs
1562  * to allow userpace to pass in arbitray "- -" device tupples.
1563  */
1564 static sector_t __rdev_sectors(struct raid_set *rs)
1565 {
1566 	int i;
1567 
1568 	for (i = 0; i < rs->md.raid_disks; i++) {
1569 		struct md_rdev *rdev = &rs->dev[i].rdev;
1570 
1571 		if (!test_bit(Journal, &rdev->flags) &&
1572 		    rdev->bdev && rdev->sectors)
1573 			return rdev->sectors;
1574 	}
1575 
1576 	return 0;
1577 }
1578 
1579 /* Calculate the sectors per device and per array used for @rs */
1580 static int rs_set_dev_and_array_sectors(struct raid_set *rs, bool use_mddev)
1581 {
1582 	int delta_disks;
1583 	unsigned int data_stripes;
1584 	struct mddev *mddev = &rs->md;
1585 	struct md_rdev *rdev;
1586 	sector_t array_sectors = rs->ti->len, dev_sectors = rs->ti->len;
1587 
1588 	if (use_mddev) {
1589 		delta_disks = mddev->delta_disks;
1590 		data_stripes = mddev_data_stripes(rs);
1591 	} else {
1592 		delta_disks = rs->delta_disks;
1593 		data_stripes = rs_data_stripes(rs);
1594 	}
1595 
1596 	/* Special raid1 case w/o delta_disks support (yet) */
1597 	if (rt_is_raid1(rs->raid_type))
1598 		;
1599 	else if (rt_is_raid10(rs->raid_type)) {
1600 		if (rs->raid10_copies < 2 ||
1601 		    delta_disks < 0) {
1602 			rs->ti->error = "Bogus raid10 data copies or delta disks";
1603 			return -EINVAL;
1604 		}
1605 
1606 		dev_sectors *= rs->raid10_copies;
1607 		if (sector_div(dev_sectors, data_stripes))
1608 			goto bad;
1609 
1610 		array_sectors = (data_stripes + delta_disks) * dev_sectors;
1611 		if (sector_div(array_sectors, rs->raid10_copies))
1612 			goto bad;
1613 
1614 	} else if (sector_div(dev_sectors, data_stripes))
1615 		goto bad;
1616 
1617 	else
1618 		/* Striped layouts */
1619 		array_sectors = (data_stripes + delta_disks) * dev_sectors;
1620 
1621 	rdev_for_each(rdev, mddev)
1622 		if (!test_bit(Journal, &rdev->flags))
1623 			rdev->sectors = dev_sectors;
1624 
1625 	mddev->array_sectors = array_sectors;
1626 	mddev->dev_sectors = dev_sectors;
1627 
1628 	return 0;
1629 bad:
1630 	rs->ti->error = "Target length not divisible by number of data devices";
1631 	return -EINVAL;
1632 }
1633 
1634 /* Setup recovery on @rs */
1635 static void __rs_setup_recovery(struct raid_set *rs, sector_t dev_sectors)
1636 {
1637 	/* raid0 does not recover */
1638 	if (rs_is_raid0(rs))
1639 		rs->md.recovery_cp = MaxSector;
1640 	/*
1641 	 * A raid6 set has to be recovered either
1642 	 * completely or for the grown part to
1643 	 * ensure proper parity and Q-Syndrome
1644 	 */
1645 	else if (rs_is_raid6(rs))
1646 		rs->md.recovery_cp = dev_sectors;
1647 	/*
1648 	 * Other raid set types may skip recovery
1649 	 * depending on the 'nosync' flag.
1650 	 */
1651 	else
1652 		rs->md.recovery_cp = test_bit(__CTR_FLAG_NOSYNC, &rs->ctr_flags)
1653 				     ? MaxSector : dev_sectors;
1654 }
1655 
1656 /* Setup recovery on @rs based on raid type, device size and 'nosync' flag */
1657 static void rs_setup_recovery(struct raid_set *rs, sector_t dev_sectors)
1658 {
1659 	if (!dev_sectors)
1660 		/* New raid set or 'sync' flag provided */
1661 		__rs_setup_recovery(rs, 0);
1662 	else if (dev_sectors == MaxSector)
1663 		/* Prevent recovery */
1664 		__rs_setup_recovery(rs, MaxSector);
1665 	else if (__rdev_sectors(rs) < dev_sectors)
1666 		/* Grown raid set */
1667 		__rs_setup_recovery(rs, __rdev_sectors(rs));
1668 	else
1669 		__rs_setup_recovery(rs, MaxSector);
1670 }
1671 
1672 static void do_table_event(struct work_struct *ws)
1673 {
1674 	struct raid_set *rs = container_of(ws, struct raid_set, md.event_work);
1675 
1676 	smp_rmb(); /* Make sure we access most actual mddev properties */
1677 	if (!rs_is_reshaping(rs))
1678 		rs_set_capacity(rs);
1679 	dm_table_event(rs->ti->table);
1680 }
1681 
1682 static int raid_is_congested(struct dm_target_callbacks *cb, int bits)
1683 {
1684 	struct raid_set *rs = container_of(cb, struct raid_set, callbacks);
1685 
1686 	return mddev_congested(&rs->md, bits);
1687 }
1688 
1689 /*
1690  * Make sure a valid takover (level switch) is being requested on @rs
1691  *
1692  * Conversions of raid sets from one MD personality to another
1693  * have to conform to restrictions which are enforced here.
1694  */
1695 static int rs_check_takeover(struct raid_set *rs)
1696 {
1697 	struct mddev *mddev = &rs->md;
1698 	unsigned int near_copies;
1699 
1700 	if (rs->md.degraded) {
1701 		rs->ti->error = "Can't takeover degraded raid set";
1702 		return -EPERM;
1703 	}
1704 
1705 	if (rs_is_reshaping(rs)) {
1706 		rs->ti->error = "Can't takeover reshaping raid set";
1707 		return -EPERM;
1708 	}
1709 
1710 	switch (mddev->level) {
1711 	case 0:
1712 		/* raid0 -> raid1/5 with one disk */
1713 		if ((mddev->new_level == 1 || mddev->new_level == 5) &&
1714 		    mddev->raid_disks == 1)
1715 			return 0;
1716 
1717 		/* raid0 -> raid10 */
1718 		if (mddev->new_level == 10 &&
1719 		    !(rs->raid_disks % mddev->raid_disks))
1720 			return 0;
1721 
1722 		/* raid0 with multiple disks -> raid4/5/6 */
1723 		if (__within_range(mddev->new_level, 4, 6) &&
1724 		    mddev->new_layout == ALGORITHM_PARITY_N &&
1725 		    mddev->raid_disks > 1)
1726 			return 0;
1727 
1728 		break;
1729 
1730 	case 10:
1731 		/* Can't takeover raid10_offset! */
1732 		if (__is_raid10_offset(mddev->layout))
1733 			break;
1734 
1735 		near_copies = __raid10_near_copies(mddev->layout);
1736 
1737 		/* raid10* -> raid0 */
1738 		if (mddev->new_level == 0) {
1739 			/* Can takeover raid10_near with raid disks divisable by data copies! */
1740 			if (near_copies > 1 &&
1741 			    !(mddev->raid_disks % near_copies)) {
1742 				mddev->raid_disks /= near_copies;
1743 				mddev->delta_disks = mddev->raid_disks;
1744 				return 0;
1745 			}
1746 
1747 			/* Can takeover raid10_far */
1748 			if (near_copies == 1 &&
1749 			    __raid10_far_copies(mddev->layout) > 1)
1750 				return 0;
1751 
1752 			break;
1753 		}
1754 
1755 		/* raid10_{near,far} -> raid1 */
1756 		if (mddev->new_level == 1 &&
1757 		    max(near_copies, __raid10_far_copies(mddev->layout)) == mddev->raid_disks)
1758 			return 0;
1759 
1760 		/* raid10_{near,far} with 2 disks -> raid4/5 */
1761 		if (__within_range(mddev->new_level, 4, 5) &&
1762 		    mddev->raid_disks == 2)
1763 			return 0;
1764 		break;
1765 
1766 	case 1:
1767 		/* raid1 with 2 disks -> raid4/5 */
1768 		if (__within_range(mddev->new_level, 4, 5) &&
1769 		    mddev->raid_disks == 2) {
1770 			mddev->degraded = 1;
1771 			return 0;
1772 		}
1773 
1774 		/* raid1 -> raid0 */
1775 		if (mddev->new_level == 0 &&
1776 		    mddev->raid_disks == 1)
1777 			return 0;
1778 
1779 		/* raid1 -> raid10 */
1780 		if (mddev->new_level == 10)
1781 			return 0;
1782 		break;
1783 
1784 	case 4:
1785 		/* raid4 -> raid0 */
1786 		if (mddev->new_level == 0)
1787 			return 0;
1788 
1789 		/* raid4 -> raid1/5 with 2 disks */
1790 		if ((mddev->new_level == 1 || mddev->new_level == 5) &&
1791 		    mddev->raid_disks == 2)
1792 			return 0;
1793 
1794 		/* raid4 -> raid5/6 with parity N */
1795 		if (__within_range(mddev->new_level, 5, 6) &&
1796 		    mddev->layout == ALGORITHM_PARITY_N)
1797 			return 0;
1798 		break;
1799 
1800 	case 5:
1801 		/* raid5 with parity N -> raid0 */
1802 		if (mddev->new_level == 0 &&
1803 		    mddev->layout == ALGORITHM_PARITY_N)
1804 			return 0;
1805 
1806 		/* raid5 with parity N -> raid4 */
1807 		if (mddev->new_level == 4 &&
1808 		    mddev->layout == ALGORITHM_PARITY_N)
1809 			return 0;
1810 
1811 		/* raid5 with 2 disks -> raid1/4/10 */
1812 		if ((mddev->new_level == 1 || mddev->new_level == 4 || mddev->new_level == 10) &&
1813 		    mddev->raid_disks == 2)
1814 			return 0;
1815 
1816 		/* raid5_* ->  raid6_*_6 with Q-Syndrome N (e.g. raid5_ra -> raid6_ra_6 */
1817 		if (mddev->new_level == 6 &&
1818 		    ((mddev->layout == ALGORITHM_PARITY_N && mddev->new_layout == ALGORITHM_PARITY_N) ||
1819 		      __within_range(mddev->new_layout, ALGORITHM_LEFT_ASYMMETRIC_6, ALGORITHM_RIGHT_SYMMETRIC_6)))
1820 			return 0;
1821 		break;
1822 
1823 	case 6:
1824 		/* raid6 with parity N -> raid0 */
1825 		if (mddev->new_level == 0 &&
1826 		    mddev->layout == ALGORITHM_PARITY_N)
1827 			return 0;
1828 
1829 		/* raid6 with parity N -> raid4 */
1830 		if (mddev->new_level == 4 &&
1831 		    mddev->layout == ALGORITHM_PARITY_N)
1832 			return 0;
1833 
1834 		/* raid6_*_n with Q-Syndrome N -> raid5_* */
1835 		if (mddev->new_level == 5 &&
1836 		    ((mddev->layout == ALGORITHM_PARITY_N && mddev->new_layout == ALGORITHM_PARITY_N) ||
1837 		     __within_range(mddev->new_layout, ALGORITHM_LEFT_ASYMMETRIC, ALGORITHM_RIGHT_SYMMETRIC)))
1838 			return 0;
1839 
1840 	default:
1841 		break;
1842 	}
1843 
1844 	rs->ti->error = "takeover not possible";
1845 	return -EINVAL;
1846 }
1847 
1848 /* True if @rs requested to be taken over */
1849 static bool rs_takeover_requested(struct raid_set *rs)
1850 {
1851 	return rs->md.new_level != rs->md.level;
1852 }
1853 
1854 /* True if @rs is requested to reshape by ctr */
1855 static bool rs_reshape_requested(struct raid_set *rs)
1856 {
1857 	bool change;
1858 	struct mddev *mddev = &rs->md;
1859 
1860 	if (rs_takeover_requested(rs))
1861 		return false;
1862 
1863 	if (!mddev->level)
1864 		return false;
1865 
1866 	change = mddev->new_layout != mddev->layout ||
1867 		 mddev->new_chunk_sectors != mddev->chunk_sectors ||
1868 		 rs->delta_disks;
1869 
1870 	/* Historical case to support raid1 reshape without delta disks */
1871 	if (mddev->level == 1) {
1872 		if (rs->delta_disks)
1873 			return !!rs->delta_disks;
1874 
1875 		return !change &&
1876 		       mddev->raid_disks != rs->raid_disks;
1877 	}
1878 
1879 	if (mddev->level == 10)
1880 		return change &&
1881 		       !__is_raid10_far(mddev->new_layout) &&
1882 		       rs->delta_disks >= 0;
1883 
1884 	return change;
1885 }
1886 
1887 /*  Features */
1888 #define	FEATURE_FLAG_SUPPORTS_V190	0x1 /* Supports extended superblock */
1889 
1890 /* State flags for sb->flags */
1891 #define	SB_FLAG_RESHAPE_ACTIVE		0x1
1892 #define	SB_FLAG_RESHAPE_BACKWARDS	0x2
1893 
1894 /*
1895  * This structure is never routinely used by userspace, unlike md superblocks.
1896  * Devices with this superblock should only ever be accessed via device-mapper.
1897  */
1898 #define DM_RAID_MAGIC 0x64526D44
1899 struct dm_raid_superblock {
1900 	__le32 magic;		/* "DmRd" */
1901 	__le32 compat_features;	/* Used to indicate compatible features (like 1.9.0 ondisk metadata extension) */
1902 
1903 	__le32 num_devices;	/* Number of devices in this raid set. (Max 64) */
1904 	__le32 array_position;	/* The position of this drive in the raid set */
1905 
1906 	__le64 events;		/* Incremented by md when superblock updated */
1907 	__le64 failed_devices;	/* Pre 1.9.0 part of bit field of devices to */
1908 				/* indicate failures (see extension below) */
1909 
1910 	/*
1911 	 * This offset tracks the progress of the repair or replacement of
1912 	 * an individual drive.
1913 	 */
1914 	__le64 disk_recovery_offset;
1915 
1916 	/*
1917 	 * This offset tracks the progress of the initial raid set
1918 	 * synchronisation/parity calculation.
1919 	 */
1920 	__le64 array_resync_offset;
1921 
1922 	/*
1923 	 * raid characteristics
1924 	 */
1925 	__le32 level;
1926 	__le32 layout;
1927 	__le32 stripe_sectors;
1928 
1929 	/********************************************************************
1930 	 * BELOW FOLLOW V1.9.0 EXTENSIONS TO THE PRISTINE SUPERBLOCK FORMAT!!!
1931 	 *
1932 	 * FEATURE_FLAG_SUPPORTS_V190 in the compat_features member indicates that those exist
1933 	 */
1934 
1935 	__le32 flags; /* Flags defining array states for reshaping */
1936 
1937 	/*
1938 	 * This offset tracks the progress of a raid
1939 	 * set reshape in order to be able to restart it
1940 	 */
1941 	__le64 reshape_position;
1942 
1943 	/*
1944 	 * These define the properties of the array in case of an interrupted reshape
1945 	 */
1946 	__le32 new_level;
1947 	__le32 new_layout;
1948 	__le32 new_stripe_sectors;
1949 	__le32 delta_disks;
1950 
1951 	__le64 array_sectors; /* Array size in sectors */
1952 
1953 	/*
1954 	 * Sector offsets to data on devices (reshaping).
1955 	 * Needed to support out of place reshaping, thus
1956 	 * not writing over any stripes whilst converting
1957 	 * them from old to new layout
1958 	 */
1959 	__le64 data_offset;
1960 	__le64 new_data_offset;
1961 
1962 	__le64 sectors; /* Used device size in sectors */
1963 
1964 	/*
1965 	 * Additonal Bit field of devices indicating failures to support
1966 	 * up to 256 devices with the 1.9.0 on-disk metadata format
1967 	 */
1968 	__le64 extended_failed_devices[DISKS_ARRAY_ELEMS - 1];
1969 
1970 	__le32 incompat_features;	/* Used to indicate any incompatible features */
1971 
1972 	/* Always set rest up to logical block size to 0 when writing (see get_metadata_device() below). */
1973 } __packed;
1974 
1975 /*
1976  * Check for reshape constraints on raid set @rs:
1977  *
1978  * - reshape function non-existent
1979  * - degraded set
1980  * - ongoing recovery
1981  * - ongoing reshape
1982  *
1983  * Returns 0 if none or -EPERM if given constraint
1984  * and error message reference in @errmsg
1985  */
1986 static int rs_check_reshape(struct raid_set *rs)
1987 {
1988 	struct mddev *mddev = &rs->md;
1989 
1990 	if (!mddev->pers || !mddev->pers->check_reshape)
1991 		rs->ti->error = "Reshape not supported";
1992 	else if (mddev->degraded)
1993 		rs->ti->error = "Can't reshape degraded raid set";
1994 	else if (rs_is_recovering(rs))
1995 		rs->ti->error = "Convert request on recovering raid set prohibited";
1996 	else if (rs_is_reshaping(rs))
1997 		rs->ti->error = "raid set already reshaping!";
1998 	else if (!(rs_is_raid1(rs) || rs_is_raid10(rs) || rs_is_raid456(rs)))
1999 		rs->ti->error = "Reshaping only supported for raid1/4/5/6/10";
2000 	else
2001 		return 0;
2002 
2003 	return -EPERM;
2004 }
2005 
2006 static int read_disk_sb(struct md_rdev *rdev, int size, bool force_reload)
2007 {
2008 	BUG_ON(!rdev->sb_page);
2009 
2010 	if (rdev->sb_loaded && !force_reload)
2011 		return 0;
2012 
2013 	rdev->sb_loaded = 0;
2014 
2015 	if (!sync_page_io(rdev, 0, size, rdev->sb_page, REQ_OP_READ, 0, true)) {
2016 		DMERR("Failed to read superblock of device at position %d",
2017 		      rdev->raid_disk);
2018 		md_error(rdev->mddev, rdev);
2019 		set_bit(Faulty, &rdev->flags);
2020 		return -EIO;
2021 	}
2022 
2023 	rdev->sb_loaded = 1;
2024 
2025 	return 0;
2026 }
2027 
2028 static void sb_retrieve_failed_devices(struct dm_raid_superblock *sb, uint64_t *failed_devices)
2029 {
2030 	failed_devices[0] = le64_to_cpu(sb->failed_devices);
2031 	memset(failed_devices + 1, 0, sizeof(sb->extended_failed_devices));
2032 
2033 	if (le32_to_cpu(sb->compat_features) & FEATURE_FLAG_SUPPORTS_V190) {
2034 		int i = ARRAY_SIZE(sb->extended_failed_devices);
2035 
2036 		while (i--)
2037 			failed_devices[i+1] = le64_to_cpu(sb->extended_failed_devices[i]);
2038 	}
2039 }
2040 
2041 static void sb_update_failed_devices(struct dm_raid_superblock *sb, uint64_t *failed_devices)
2042 {
2043 	int i = ARRAY_SIZE(sb->extended_failed_devices);
2044 
2045 	sb->failed_devices = cpu_to_le64(failed_devices[0]);
2046 	while (i--)
2047 		sb->extended_failed_devices[i] = cpu_to_le64(failed_devices[i+1]);
2048 }
2049 
2050 /*
2051  * Synchronize the superblock members with the raid set properties
2052  *
2053  * All superblock data is little endian.
2054  */
2055 static void super_sync(struct mddev *mddev, struct md_rdev *rdev)
2056 {
2057 	bool update_failed_devices = false;
2058 	unsigned int i;
2059 	uint64_t failed_devices[DISKS_ARRAY_ELEMS];
2060 	struct dm_raid_superblock *sb;
2061 	struct raid_set *rs = container_of(mddev, struct raid_set, md);
2062 
2063 	/* No metadata device, no superblock */
2064 	if (!rdev->meta_bdev)
2065 		return;
2066 
2067 	BUG_ON(!rdev->sb_page);
2068 
2069 	sb = page_address(rdev->sb_page);
2070 
2071 	sb_retrieve_failed_devices(sb, failed_devices);
2072 
2073 	for (i = 0; i < rs->raid_disks; i++)
2074 		if (!rs->dev[i].data_dev || test_bit(Faulty, &rs->dev[i].rdev.flags)) {
2075 			update_failed_devices = true;
2076 			set_bit(i, (void *) failed_devices);
2077 		}
2078 
2079 	if (update_failed_devices)
2080 		sb_update_failed_devices(sb, failed_devices);
2081 
2082 	sb->magic = cpu_to_le32(DM_RAID_MAGIC);
2083 	sb->compat_features = cpu_to_le32(FEATURE_FLAG_SUPPORTS_V190);
2084 
2085 	sb->num_devices = cpu_to_le32(mddev->raid_disks);
2086 	sb->array_position = cpu_to_le32(rdev->raid_disk);
2087 
2088 	sb->events = cpu_to_le64(mddev->events);
2089 
2090 	sb->disk_recovery_offset = cpu_to_le64(rdev->recovery_offset);
2091 	sb->array_resync_offset = cpu_to_le64(mddev->recovery_cp);
2092 
2093 	sb->level = cpu_to_le32(mddev->level);
2094 	sb->layout = cpu_to_le32(mddev->layout);
2095 	sb->stripe_sectors = cpu_to_le32(mddev->chunk_sectors);
2096 
2097 	/********************************************************************
2098 	 * BELOW FOLLOW V1.9.0 EXTENSIONS TO THE PRISTINE SUPERBLOCK FORMAT!!!
2099 	 *
2100 	 * FEATURE_FLAG_SUPPORTS_V190 in the compat_features member indicates that those exist
2101 	 */
2102 	sb->new_level = cpu_to_le32(mddev->new_level);
2103 	sb->new_layout = cpu_to_le32(mddev->new_layout);
2104 	sb->new_stripe_sectors = cpu_to_le32(mddev->new_chunk_sectors);
2105 
2106 	sb->delta_disks = cpu_to_le32(mddev->delta_disks);
2107 
2108 	smp_rmb(); /* Make sure we access most recent reshape position */
2109 	sb->reshape_position = cpu_to_le64(mddev->reshape_position);
2110 	if (le64_to_cpu(sb->reshape_position) != MaxSector) {
2111 		/* Flag ongoing reshape */
2112 		sb->flags |= cpu_to_le32(SB_FLAG_RESHAPE_ACTIVE);
2113 
2114 		if (mddev->delta_disks < 0 || mddev->reshape_backwards)
2115 			sb->flags |= cpu_to_le32(SB_FLAG_RESHAPE_BACKWARDS);
2116 	} else {
2117 		/* Clear reshape flags */
2118 		sb->flags &= ~(cpu_to_le32(SB_FLAG_RESHAPE_ACTIVE|SB_FLAG_RESHAPE_BACKWARDS));
2119 	}
2120 
2121 	sb->array_sectors = cpu_to_le64(mddev->array_sectors);
2122 	sb->data_offset = cpu_to_le64(rdev->data_offset);
2123 	sb->new_data_offset = cpu_to_le64(rdev->new_data_offset);
2124 	sb->sectors = cpu_to_le64(rdev->sectors);
2125 	sb->incompat_features = cpu_to_le32(0);
2126 
2127 	/* Zero out the rest of the payload after the size of the superblock */
2128 	memset(sb + 1, 0, rdev->sb_size - sizeof(*sb));
2129 }
2130 
2131 /*
2132  * super_load
2133  *
2134  * This function creates a superblock if one is not found on the device
2135  * and will decide which superblock to use if there's a choice.
2136  *
2137  * Return: 1 if use rdev, 0 if use refdev, -Exxx otherwise
2138  */
2139 static int super_load(struct md_rdev *rdev, struct md_rdev *refdev)
2140 {
2141 	int r;
2142 	struct dm_raid_superblock *sb;
2143 	struct dm_raid_superblock *refsb;
2144 	uint64_t events_sb, events_refsb;
2145 
2146 	r = read_disk_sb(rdev, rdev->sb_size, false);
2147 	if (r)
2148 		return r;
2149 
2150 	sb = page_address(rdev->sb_page);
2151 
2152 	/*
2153 	 * Two cases that we want to write new superblocks and rebuild:
2154 	 * 1) New device (no matching magic number)
2155 	 * 2) Device specified for rebuild (!In_sync w/ offset == 0)
2156 	 */
2157 	if ((sb->magic != cpu_to_le32(DM_RAID_MAGIC)) ||
2158 	    (!test_bit(In_sync, &rdev->flags) && !rdev->recovery_offset)) {
2159 		super_sync(rdev->mddev, rdev);
2160 
2161 		set_bit(FirstUse, &rdev->flags);
2162 		sb->compat_features = cpu_to_le32(FEATURE_FLAG_SUPPORTS_V190);
2163 
2164 		/* Force writing of superblocks to disk */
2165 		set_bit(MD_SB_CHANGE_DEVS, &rdev->mddev->sb_flags);
2166 
2167 		/* Any superblock is better than none, choose that if given */
2168 		return refdev ? 0 : 1;
2169 	}
2170 
2171 	if (!refdev)
2172 		return 1;
2173 
2174 	events_sb = le64_to_cpu(sb->events);
2175 
2176 	refsb = page_address(refdev->sb_page);
2177 	events_refsb = le64_to_cpu(refsb->events);
2178 
2179 	return (events_sb > events_refsb) ? 1 : 0;
2180 }
2181 
2182 static int super_init_validation(struct raid_set *rs, struct md_rdev *rdev)
2183 {
2184 	int role;
2185 	unsigned int d;
2186 	struct mddev *mddev = &rs->md;
2187 	uint64_t events_sb;
2188 	uint64_t failed_devices[DISKS_ARRAY_ELEMS];
2189 	struct dm_raid_superblock *sb;
2190 	uint32_t new_devs = 0, rebuild_and_new = 0, rebuilds = 0;
2191 	struct md_rdev *r;
2192 	struct dm_raid_superblock *sb2;
2193 
2194 	sb = page_address(rdev->sb_page);
2195 	events_sb = le64_to_cpu(sb->events);
2196 
2197 	/*
2198 	 * Initialise to 1 if this is a new superblock.
2199 	 */
2200 	mddev->events = events_sb ? : 1;
2201 
2202 	mddev->reshape_position = MaxSector;
2203 
2204 	mddev->raid_disks = le32_to_cpu(sb->num_devices);
2205 	mddev->level = le32_to_cpu(sb->level);
2206 	mddev->layout = le32_to_cpu(sb->layout);
2207 	mddev->chunk_sectors = le32_to_cpu(sb->stripe_sectors);
2208 
2209 	/*
2210 	 * Reshaping is supported, e.g. reshape_position is valid
2211 	 * in superblock and superblock content is authoritative.
2212 	 */
2213 	if (le32_to_cpu(sb->compat_features) & FEATURE_FLAG_SUPPORTS_V190) {
2214 		/* Superblock is authoritative wrt given raid set layout! */
2215 		mddev->new_level = le32_to_cpu(sb->new_level);
2216 		mddev->new_layout = le32_to_cpu(sb->new_layout);
2217 		mddev->new_chunk_sectors = le32_to_cpu(sb->new_stripe_sectors);
2218 		mddev->delta_disks = le32_to_cpu(sb->delta_disks);
2219 		mddev->array_sectors = le64_to_cpu(sb->array_sectors);
2220 
2221 		/* raid was reshaping and got interrupted */
2222 		if (le32_to_cpu(sb->flags) & SB_FLAG_RESHAPE_ACTIVE) {
2223 			if (test_bit(__CTR_FLAG_DELTA_DISKS, &rs->ctr_flags)) {
2224 				DMERR("Reshape requested but raid set is still reshaping");
2225 				return -EINVAL;
2226 			}
2227 
2228 			if (mddev->delta_disks < 0 ||
2229 			    (!mddev->delta_disks && (le32_to_cpu(sb->flags) & SB_FLAG_RESHAPE_BACKWARDS)))
2230 				mddev->reshape_backwards = 1;
2231 			else
2232 				mddev->reshape_backwards = 0;
2233 
2234 			mddev->reshape_position = le64_to_cpu(sb->reshape_position);
2235 			rs->raid_type = get_raid_type_by_ll(mddev->level, mddev->layout);
2236 		}
2237 
2238 	} else {
2239 		/*
2240 		 * No takeover/reshaping, because we don't have the extended v1.9.0 metadata
2241 		 */
2242 		struct raid_type *rt_cur = get_raid_type_by_ll(mddev->level, mddev->layout);
2243 		struct raid_type *rt_new = get_raid_type_by_ll(mddev->new_level, mddev->new_layout);
2244 
2245 		if (rs_takeover_requested(rs)) {
2246 			if (rt_cur && rt_new)
2247 				DMERR("Takeover raid sets from %s to %s not yet supported by metadata. (raid level change)",
2248 				      rt_cur->name, rt_new->name);
2249 			else
2250 				DMERR("Takeover raid sets not yet supported by metadata. (raid level change)");
2251 			return -EINVAL;
2252 		} else if (rs_reshape_requested(rs)) {
2253 			DMERR("Reshaping raid sets not yet supported by metadata. (raid layout change keeping level)");
2254 			if (mddev->layout != mddev->new_layout) {
2255 				if (rt_cur && rt_new)
2256 					DMERR("	 current layout %s vs new layout %s",
2257 					      rt_cur->name, rt_new->name);
2258 				else
2259 					DMERR("	 current layout 0x%X vs new layout 0x%X",
2260 					      le32_to_cpu(sb->layout), mddev->new_layout);
2261 			}
2262 			if (mddev->chunk_sectors != mddev->new_chunk_sectors)
2263 				DMERR("	 current stripe sectors %u vs new stripe sectors %u",
2264 				      mddev->chunk_sectors, mddev->new_chunk_sectors);
2265 			if (rs->delta_disks)
2266 				DMERR("	 current %u disks vs new %u disks",
2267 				      mddev->raid_disks, mddev->raid_disks + rs->delta_disks);
2268 			if (rs_is_raid10(rs)) {
2269 				DMERR("	 Old layout: %s w/ %u copies",
2270 				      raid10_md_layout_to_format(mddev->layout),
2271 				      raid10_md_layout_to_copies(mddev->layout));
2272 				DMERR("	 New layout: %s w/ %u copies",
2273 				      raid10_md_layout_to_format(mddev->new_layout),
2274 				      raid10_md_layout_to_copies(mddev->new_layout));
2275 			}
2276 			return -EINVAL;
2277 		}
2278 
2279 		DMINFO("Discovered old metadata format; upgrading to extended metadata format");
2280 	}
2281 
2282 	if (!test_bit(__CTR_FLAG_NOSYNC, &rs->ctr_flags))
2283 		mddev->recovery_cp = le64_to_cpu(sb->array_resync_offset);
2284 
2285 	/*
2286 	 * During load, we set FirstUse if a new superblock was written.
2287 	 * There are two reasons we might not have a superblock:
2288 	 * 1) The raid set is brand new - in which case, all of the
2289 	 *    devices must have their In_sync bit set.	Also,
2290 	 *    recovery_cp must be 0, unless forced.
2291 	 * 2) This is a new device being added to an old raid set
2292 	 *    and the new device needs to be rebuilt - in which
2293 	 *    case the In_sync bit will /not/ be set and
2294 	 *    recovery_cp must be MaxSector.
2295 	 * 3) This is/are a new device(s) being added to an old
2296 	 *    raid set during takeover to a higher raid level
2297 	 *    to provide capacity for redundancy or during reshape
2298 	 *    to add capacity to grow the raid set.
2299 	 */
2300 	d = 0;
2301 	rdev_for_each(r, mddev) {
2302 		if (test_bit(Journal, &rdev->flags))
2303 			continue;
2304 
2305 		if (test_bit(FirstUse, &r->flags))
2306 			new_devs++;
2307 
2308 		if (!test_bit(In_sync, &r->flags)) {
2309 			DMINFO("Device %d specified for rebuild; clearing superblock",
2310 				r->raid_disk);
2311 			rebuilds++;
2312 
2313 			if (test_bit(FirstUse, &r->flags))
2314 				rebuild_and_new++;
2315 		}
2316 
2317 		d++;
2318 	}
2319 
2320 	if (new_devs == rs->raid_disks || !rebuilds) {
2321 		/* Replace a broken device */
2322 		if (new_devs == 1 && !rs->delta_disks)
2323 			;
2324 		if (new_devs == rs->raid_disks) {
2325 			DMINFO("Superblocks created for new raid set");
2326 			set_bit(MD_ARRAY_FIRST_USE, &mddev->flags);
2327 		} else if (new_devs != rebuilds &&
2328 			   new_devs != rs->delta_disks) {
2329 			DMERR("New device injected into existing raid set without "
2330 			      "'delta_disks' or 'rebuild' parameter specified");
2331 			return -EINVAL;
2332 		}
2333 	} else if (new_devs && new_devs != rebuilds) {
2334 		DMERR("%u 'rebuild' devices cannot be injected into"
2335 		      " a raid set with %u other first-time devices",
2336 		      rebuilds, new_devs);
2337 		return -EINVAL;
2338 	} else if (rebuilds) {
2339 		if (rebuild_and_new && rebuilds != rebuild_and_new) {
2340 			DMERR("new device%s provided without 'rebuild'",
2341 			      new_devs > 1 ? "s" : "");
2342 			return -EINVAL;
2343 		} else if (rs_is_recovering(rs)) {
2344 			DMERR("'rebuild' specified while raid set is not in-sync (recovery_cp=%llu)",
2345 			      (unsigned long long) mddev->recovery_cp);
2346 			return -EINVAL;
2347 		} else if (rs_is_reshaping(rs)) {
2348 			DMERR("'rebuild' specified while raid set is being reshaped (reshape_position=%llu)",
2349 			      (unsigned long long) mddev->reshape_position);
2350 			return -EINVAL;
2351 		}
2352 	}
2353 
2354 	/*
2355 	 * Now we set the Faulty bit for those devices that are
2356 	 * recorded in the superblock as failed.
2357 	 */
2358 	sb_retrieve_failed_devices(sb, failed_devices);
2359 	rdev_for_each(r, mddev) {
2360 		if (test_bit(Journal, &rdev->flags) ||
2361 		    !r->sb_page)
2362 			continue;
2363 		sb2 = page_address(r->sb_page);
2364 		sb2->failed_devices = 0;
2365 		memset(sb2->extended_failed_devices, 0, sizeof(sb2->extended_failed_devices));
2366 
2367 		/*
2368 		 * Check for any device re-ordering.
2369 		 */
2370 		if (!test_bit(FirstUse, &r->flags) && (r->raid_disk >= 0)) {
2371 			role = le32_to_cpu(sb2->array_position);
2372 			if (role < 0)
2373 				continue;
2374 
2375 			if (role != r->raid_disk) {
2376 				if (rs_is_raid10(rs) && __is_raid10_near(mddev->layout)) {
2377 					if (mddev->raid_disks % __raid10_near_copies(mddev->layout) ||
2378 					    rs->raid_disks % rs->raid10_copies) {
2379 						rs->ti->error =
2380 							"Cannot change raid10 near set to odd # of devices!";
2381 						return -EINVAL;
2382 					}
2383 
2384 					sb2->array_position = cpu_to_le32(r->raid_disk);
2385 
2386 				} else if (!(rs_is_raid10(rs) && rt_is_raid0(rs->raid_type)) &&
2387 					   !(rs_is_raid0(rs) && rt_is_raid10(rs->raid_type)) &&
2388 					   !rt_is_raid1(rs->raid_type)) {
2389 					rs->ti->error = "Cannot change device positions in raid set";
2390 					return -EINVAL;
2391 				}
2392 
2393 				DMINFO("raid device #%d now at position #%d", role, r->raid_disk);
2394 			}
2395 
2396 			/*
2397 			 * Partial recovery is performed on
2398 			 * returning failed devices.
2399 			 */
2400 			if (test_bit(role, (void *) failed_devices))
2401 				set_bit(Faulty, &r->flags);
2402 		}
2403 	}
2404 
2405 	return 0;
2406 }
2407 
2408 static int super_validate(struct raid_set *rs, struct md_rdev *rdev)
2409 {
2410 	struct mddev *mddev = &rs->md;
2411 	struct dm_raid_superblock *sb;
2412 
2413 	if (rs_is_raid0(rs) || !rdev->sb_page || rdev->raid_disk < 0)
2414 		return 0;
2415 
2416 	sb = page_address(rdev->sb_page);
2417 
2418 	/*
2419 	 * If mddev->events is not set, we know we have not yet initialized
2420 	 * the array.
2421 	 */
2422 	if (!mddev->events && super_init_validation(rs, rdev))
2423 		return -EINVAL;
2424 
2425 	if (le32_to_cpu(sb->compat_features) &&
2426 	    le32_to_cpu(sb->compat_features) != FEATURE_FLAG_SUPPORTS_V190) {
2427 		rs->ti->error = "Unable to assemble array: Unknown flag(s) in compatible feature flags";
2428 		return -EINVAL;
2429 	}
2430 
2431 	if (sb->incompat_features) {
2432 		rs->ti->error = "Unable to assemble array: No incompatible feature flags supported yet";
2433 		return -EINVAL;
2434 	}
2435 
2436 	/* Enable bitmap creation for RAID levels != 0 */
2437 	mddev->bitmap_info.offset = rt_is_raid0(rs->raid_type) ? 0 : to_sector(4096);
2438 	mddev->bitmap_info.default_offset = mddev->bitmap_info.offset;
2439 
2440 	if (!test_and_clear_bit(FirstUse, &rdev->flags)) {
2441 		/*
2442 		 * Retrieve rdev size stored in superblock to be prepared for shrink.
2443 		 * Check extended superblock members are present otherwise the size
2444 		 * will not be set!
2445 		 */
2446 		if (le32_to_cpu(sb->compat_features) & FEATURE_FLAG_SUPPORTS_V190)
2447 			rdev->sectors = le64_to_cpu(sb->sectors);
2448 
2449 		rdev->recovery_offset = le64_to_cpu(sb->disk_recovery_offset);
2450 		if (rdev->recovery_offset == MaxSector)
2451 			set_bit(In_sync, &rdev->flags);
2452 		/*
2453 		 * If no reshape in progress -> we're recovering single
2454 		 * disk(s) and have to set the device(s) to out-of-sync
2455 		 */
2456 		else if (!rs_is_reshaping(rs))
2457 			clear_bit(In_sync, &rdev->flags); /* Mandatory for recovery */
2458 	}
2459 
2460 	/*
2461 	 * If a device comes back, set it as not In_sync and no longer faulty.
2462 	 */
2463 	if (test_and_clear_bit(Faulty, &rdev->flags)) {
2464 		rdev->recovery_offset = 0;
2465 		clear_bit(In_sync, &rdev->flags);
2466 		rdev->saved_raid_disk = rdev->raid_disk;
2467 	}
2468 
2469 	/* Reshape support -> restore repective data offsets */
2470 	rdev->data_offset = le64_to_cpu(sb->data_offset);
2471 	rdev->new_data_offset = le64_to_cpu(sb->new_data_offset);
2472 
2473 	return 0;
2474 }
2475 
2476 /*
2477  * Analyse superblocks and select the freshest.
2478  */
2479 static int analyse_superblocks(struct dm_target *ti, struct raid_set *rs)
2480 {
2481 	int r;
2482 	struct md_rdev *rdev, *freshest;
2483 	struct mddev *mddev = &rs->md;
2484 
2485 	freshest = NULL;
2486 	rdev_for_each(rdev, mddev) {
2487 		if (test_bit(Journal, &rdev->flags))
2488 			continue;
2489 
2490 		if (!rdev->meta_bdev)
2491 			continue;
2492 
2493 		/* Set superblock offset/size for metadata device. */
2494 		rdev->sb_start = 0;
2495 		rdev->sb_size = bdev_logical_block_size(rdev->meta_bdev);
2496 		if (rdev->sb_size < sizeof(struct dm_raid_superblock) || rdev->sb_size > PAGE_SIZE) {
2497 			DMERR("superblock size of a logical block is no longer valid");
2498 			return -EINVAL;
2499 		}
2500 
2501 		/*
2502 		 * Skipping super_load due to CTR_FLAG_SYNC will cause
2503 		 * the array to undergo initialization again as
2504 		 * though it were new.	This is the intended effect
2505 		 * of the "sync" directive.
2506 		 *
2507 		 * With reshaping capability added, we must ensure that
2508 		 * that the "sync" directive is disallowed during the reshape.
2509 		 */
2510 		if (test_bit(__CTR_FLAG_SYNC, &rs->ctr_flags))
2511 			continue;
2512 
2513 		r = super_load(rdev, freshest);
2514 
2515 		switch (r) {
2516 		case 1:
2517 			freshest = rdev;
2518 			break;
2519 		case 0:
2520 			break;
2521 		default:
2522 			/* This is a failure to read the superblock from the metadata device. */
2523 			/*
2524 			 * We have to keep any raid0 data/metadata device pairs or
2525 			 * the MD raid0 personality will fail to start the array.
2526 			 */
2527 			if (rs_is_raid0(rs))
2528 				continue;
2529 
2530 			/*
2531 			 * We keep the dm_devs to be able to emit the device tuple
2532 			 * properly on the table line in raid_status() (rather than
2533 			 * mistakenly acting as if '- -' got passed into the constructor).
2534 			 *
2535 			 * The rdev has to stay on the same_set list to allow for
2536 			 * the attempt to restore faulty devices on second resume.
2537 			 */
2538 			rdev->raid_disk = rdev->saved_raid_disk = -1;
2539 			break;
2540 		}
2541 	}
2542 
2543 	if (!freshest)
2544 		return 0;
2545 
2546 	/*
2547 	 * Validation of the freshest device provides the source of
2548 	 * validation for the remaining devices.
2549 	 */
2550 	rs->ti->error = "Unable to assemble array: Invalid superblocks";
2551 	if (super_validate(rs, freshest))
2552 		return -EINVAL;
2553 
2554 	if (validate_raid_redundancy(rs)) {
2555 		rs->ti->error = "Insufficient redundancy to activate array";
2556 		return -EINVAL;
2557 	}
2558 
2559 	rdev_for_each(rdev, mddev)
2560 		if (!test_bit(Journal, &rdev->flags) &&
2561 		    rdev != freshest &&
2562 		    super_validate(rs, rdev))
2563 			return -EINVAL;
2564 	return 0;
2565 }
2566 
2567 /*
2568  * Adjust data_offset and new_data_offset on all disk members of @rs
2569  * for out of place reshaping if requested by contructor
2570  *
2571  * We need free space at the beginning of each raid disk for forward
2572  * and at the end for backward reshapes which userspace has to provide
2573  * via remapping/reordering of space.
2574  */
2575 static int rs_adjust_data_offsets(struct raid_set *rs)
2576 {
2577 	sector_t data_offset = 0, new_data_offset = 0;
2578 	struct md_rdev *rdev;
2579 
2580 	/* Constructor did not request data offset change */
2581 	if (!test_bit(__CTR_FLAG_DATA_OFFSET, &rs->ctr_flags)) {
2582 		if (!rs_is_reshapable(rs))
2583 			goto out;
2584 
2585 		return 0;
2586 	}
2587 
2588 	/* HM FIXME: get InSync raid_dev? */
2589 	rdev = &rs->dev[0].rdev;
2590 
2591 	if (rs->delta_disks < 0) {
2592 		/*
2593 		 * Removing disks (reshaping backwards):
2594 		 *
2595 		 * - before reshape: data is at offset 0 and free space
2596 		 *		     is at end of each component LV
2597 		 *
2598 		 * - after reshape: data is at offset rs->data_offset != 0 on each component LV
2599 		 */
2600 		data_offset = 0;
2601 		new_data_offset = rs->data_offset;
2602 
2603 	} else if (rs->delta_disks > 0) {
2604 		/*
2605 		 * Adding disks (reshaping forwards):
2606 		 *
2607 		 * - before reshape: data is at offset rs->data_offset != 0 and
2608 		 *		     free space is at begin of each component LV
2609 		 *
2610 		 * - after reshape: data is at offset 0 on each component LV
2611 		 */
2612 		data_offset = rs->data_offset;
2613 		new_data_offset = 0;
2614 
2615 	} else {
2616 		/*
2617 		 * User space passes in 0 for data offset after having removed reshape space
2618 		 *
2619 		 * - or - (data offset != 0)
2620 		 *
2621 		 * Changing RAID layout or chunk size -> toggle offsets
2622 		 *
2623 		 * - before reshape: data is at offset rs->data_offset 0 and
2624 		 *		     free space is at end of each component LV
2625 		 *		     -or-
2626 		 *                   data is at offset rs->data_offset != 0 and
2627 		 *		     free space is at begin of each component LV
2628 		 *
2629 		 * - after reshape: data is at offset 0 if it was at offset != 0
2630 		 *                  or at offset != 0 if it was at offset 0
2631 		 *                  on each component LV
2632 		 *
2633 		 */
2634 		data_offset = rs->data_offset ? rdev->data_offset : 0;
2635 		new_data_offset = data_offset ? 0 : rs->data_offset;
2636 		set_bit(RT_FLAG_UPDATE_SBS, &rs->runtime_flags);
2637 	}
2638 
2639 	/*
2640 	 * Make sure we got a minimum amount of free sectors per device
2641 	 */
2642 	if (rs->data_offset &&
2643 	    to_sector(i_size_read(rdev->bdev->bd_inode)) - rdev->sectors < MIN_FREE_RESHAPE_SPACE) {
2644 		rs->ti->error = data_offset ? "No space for forward reshape" :
2645 					      "No space for backward reshape";
2646 		return -ENOSPC;
2647 	}
2648 out:
2649 	/* Adjust data offsets on all rdevs but on any raid4/5/6 journal device */
2650 	rdev_for_each(rdev, &rs->md) {
2651 		if (!test_bit(Journal, &rdev->flags)) {
2652 			rdev->data_offset = data_offset;
2653 			rdev->new_data_offset = new_data_offset;
2654 		}
2655 	}
2656 
2657 	return 0;
2658 }
2659 
2660 /* Userpace reordered disks -> adjust raid_disk indexes in @rs */
2661 static void __reorder_raid_disk_indexes(struct raid_set *rs)
2662 {
2663 	int i = 0;
2664 	struct md_rdev *rdev;
2665 
2666 	rdev_for_each(rdev, &rs->md) {
2667 		if (!test_bit(Journal, &rdev->flags)) {
2668 			rdev->raid_disk = i++;
2669 			rdev->saved_raid_disk = rdev->new_raid_disk = -1;
2670 		}
2671 	}
2672 }
2673 
2674 /*
2675  * Setup @rs for takeover by a different raid level
2676  */
2677 static int rs_setup_takeover(struct raid_set *rs)
2678 {
2679 	struct mddev *mddev = &rs->md;
2680 	struct md_rdev *rdev;
2681 	unsigned int d = mddev->raid_disks = rs->raid_disks;
2682 	sector_t new_data_offset = rs->dev[0].rdev.data_offset ? 0 : rs->data_offset;
2683 
2684 	if (rt_is_raid10(rs->raid_type)) {
2685 		if (mddev->level == 0) {
2686 			/* Userpace reordered disks -> adjust raid_disk indexes */
2687 			__reorder_raid_disk_indexes(rs);
2688 
2689 			/* raid0 -> raid10_far layout */
2690 			mddev->layout = raid10_format_to_md_layout(rs, ALGORITHM_RAID10_FAR,
2691 								   rs->raid10_copies);
2692 		} else if (mddev->level == 1)
2693 			/* raid1 -> raid10_near layout */
2694 			mddev->layout = raid10_format_to_md_layout(rs, ALGORITHM_RAID10_NEAR,
2695 								   rs->raid_disks);
2696 		else
2697 			return -EINVAL;
2698 
2699 	}
2700 
2701 	clear_bit(MD_ARRAY_FIRST_USE, &mddev->flags);
2702 	mddev->recovery_cp = MaxSector;
2703 
2704 	while (d--) {
2705 		rdev = &rs->dev[d].rdev;
2706 
2707 		if (test_bit(d, (void *) rs->rebuild_disks)) {
2708 			clear_bit(In_sync, &rdev->flags);
2709 			clear_bit(Faulty, &rdev->flags);
2710 			mddev->recovery_cp = rdev->recovery_offset = 0;
2711 			/* Bitmap has to be created when we do an "up" takeover */
2712 			set_bit(MD_ARRAY_FIRST_USE, &mddev->flags);
2713 		}
2714 
2715 		rdev->new_data_offset = new_data_offset;
2716 	}
2717 
2718 	return 0;
2719 }
2720 
2721 /* Prepare @rs for reshape */
2722 static int rs_prepare_reshape(struct raid_set *rs)
2723 {
2724 	bool reshape;
2725 	struct mddev *mddev = &rs->md;
2726 
2727 	if (rs_is_raid10(rs)) {
2728 		if (rs->raid_disks != mddev->raid_disks &&
2729 		    __is_raid10_near(mddev->layout) &&
2730 		    rs->raid10_copies &&
2731 		    rs->raid10_copies != __raid10_near_copies(mddev->layout)) {
2732 			/*
2733 			 * raid disk have to be multiple of data copies to allow this conversion,
2734 			 *
2735 			 * This is actually not a reshape it is a
2736 			 * rebuild of any additional mirrors per group
2737 			 */
2738 			if (rs->raid_disks % rs->raid10_copies) {
2739 				rs->ti->error = "Can't reshape raid10 mirror groups";
2740 				return -EINVAL;
2741 			}
2742 
2743 			/* Userpace reordered disks to add/remove mirrors -> adjust raid_disk indexes */
2744 			__reorder_raid_disk_indexes(rs);
2745 			mddev->layout = raid10_format_to_md_layout(rs, ALGORITHM_RAID10_NEAR,
2746 								   rs->raid10_copies);
2747 			mddev->new_layout = mddev->layout;
2748 			reshape = false;
2749 		} else
2750 			reshape = true;
2751 
2752 	} else if (rs_is_raid456(rs))
2753 		reshape = true;
2754 
2755 	else if (rs_is_raid1(rs)) {
2756 		if (rs->delta_disks) {
2757 			/* Process raid1 via delta_disks */
2758 			mddev->degraded = rs->delta_disks < 0 ? -rs->delta_disks : rs->delta_disks;
2759 			reshape = true;
2760 		} else {
2761 			/* Process raid1 without delta_disks */
2762 			mddev->raid_disks = rs->raid_disks;
2763 			reshape = false;
2764 		}
2765 	} else {
2766 		rs->ti->error = "Called with bogus raid type";
2767 		return -EINVAL;
2768 	}
2769 
2770 	if (reshape) {
2771 		set_bit(RT_FLAG_RESHAPE_RS, &rs->runtime_flags);
2772 		set_bit(RT_FLAG_UPDATE_SBS, &rs->runtime_flags);
2773 	} else if (mddev->raid_disks < rs->raid_disks)
2774 		/* Create new superblocks and bitmaps, if any new disks */
2775 		set_bit(RT_FLAG_UPDATE_SBS, &rs->runtime_flags);
2776 
2777 	return 0;
2778 }
2779 
2780 /*
2781  *
2782  * - change raid layout
2783  * - change chunk size
2784  * - add disks
2785  * - remove disks
2786  */
2787 static int rs_setup_reshape(struct raid_set *rs)
2788 {
2789 	int r = 0;
2790 	unsigned int cur_raid_devs, d;
2791 	struct mddev *mddev = &rs->md;
2792 	struct md_rdev *rdev;
2793 
2794 	mddev->delta_disks = rs->delta_disks;
2795 	cur_raid_devs = mddev->raid_disks;
2796 
2797 	/* Ignore impossible layout change whilst adding/removing disks */
2798 	if (mddev->delta_disks &&
2799 	    mddev->layout != mddev->new_layout) {
2800 		DMINFO("Ignoring invalid layout change with delta_disks=%d", rs->delta_disks);
2801 		mddev->new_layout = mddev->layout;
2802 	}
2803 
2804 	/*
2805 	 * Adjust array size:
2806 	 *
2807 	 * - in case of adding disks, array size has
2808 	 *   to grow after the disk adding reshape,
2809 	 *   which'll hapen in the event handler;
2810 	 *   reshape will happen forward, so space has to
2811 	 *   be available at the beginning of each disk
2812 	 *
2813 	 * - in case of removing disks, array size
2814 	 *   has to shrink before starting the reshape,
2815 	 *   which'll happen here;
2816 	 *   reshape will happen backward, so space has to
2817 	 *   be available at the end of each disk
2818 	 *
2819 	 * - data_offset and new_data_offset are
2820 	 *   adjusted for aforementioned out of place
2821 	 *   reshaping based on userspace passing in
2822 	 *   the "data_offset <sectors>" key/value
2823 	 *   pair via the constructor
2824 	 */
2825 
2826 	/* Add disk(s) */
2827 	if (rs->delta_disks > 0) {
2828 		/* Prepare disks for check in raid4/5/6/10 {check|start}_reshape */
2829 		for (d = cur_raid_devs; d < rs->raid_disks; d++) {
2830 			rdev = &rs->dev[d].rdev;
2831 			clear_bit(In_sync, &rdev->flags);
2832 
2833 			/*
2834 			 * save_raid_disk needs to be -1, or recovery_offset will be set to 0
2835 			 * by md, which'll store that erroneously in the superblock on reshape
2836 			 */
2837 			rdev->saved_raid_disk = -1;
2838 			rdev->raid_disk = d;
2839 
2840 			rdev->sectors = mddev->dev_sectors;
2841 			rdev->recovery_offset = rs_is_raid1(rs) ? 0 : MaxSector;
2842 		}
2843 
2844 		mddev->reshape_backwards = 0; /* adding disks -> forward reshape */
2845 
2846 	/* Remove disk(s) */
2847 	} else if (rs->delta_disks < 0) {
2848 		r = rs_set_dev_and_array_sectors(rs, true);
2849 		mddev->reshape_backwards = 1; /* removing disk(s) -> backward reshape */
2850 
2851 	/* Change layout and/or chunk size */
2852 	} else {
2853 		/*
2854 		 * Reshape layout (e.g. raid5_ls -> raid5_n) and/or chunk size:
2855 		 *
2856 		 * keeping number of disks and do layout change ->
2857 		 *
2858 		 * toggle reshape_backward depending on data_offset:
2859 		 *
2860 		 * - free space upfront -> reshape forward
2861 		 *
2862 		 * - free space at the end -> reshape backward
2863 		 *
2864 		 *
2865 		 * This utilizes free reshape space avoiding the need
2866 		 * for userspace to move (parts of) LV segments in
2867 		 * case of layout/chunksize change  (for disk
2868 		 * adding/removing reshape space has to be at
2869 		 * the proper address (see above with delta_disks):
2870 		 *
2871 		 * add disk(s)   -> begin
2872 		 * remove disk(s)-> end
2873 		 */
2874 		mddev->reshape_backwards = rs->dev[0].rdev.data_offset ? 0 : 1;
2875 	}
2876 
2877 	return r;
2878 }
2879 
2880 /*
2881  * Enable/disable discard support on RAID set depending on
2882  * RAID level and discard properties of underlying RAID members.
2883  */
2884 static void configure_discard_support(struct raid_set *rs)
2885 {
2886 	int i;
2887 	bool raid456;
2888 	struct dm_target *ti = rs->ti;
2889 
2890 	/*
2891 	 * XXX: RAID level 4,5,6 require zeroing for safety.
2892 	 */
2893 	raid456 = (rs->md.level == 4 || rs->md.level == 5 || rs->md.level == 6);
2894 
2895 	for (i = 0; i < rs->raid_disks; i++) {
2896 		struct request_queue *q;
2897 
2898 		if (!rs->dev[i].rdev.bdev)
2899 			continue;
2900 
2901 		q = bdev_get_queue(rs->dev[i].rdev.bdev);
2902 		if (!q || !blk_queue_discard(q))
2903 			return;
2904 
2905 		if (raid456) {
2906 			if (!devices_handle_discard_safely) {
2907 				DMERR("raid456 discard support disabled due to discard_zeroes_data uncertainty.");
2908 				DMERR("Set dm-raid.devices_handle_discard_safely=Y to override.");
2909 				return;
2910 			}
2911 		}
2912 	}
2913 
2914 	/*
2915 	 * RAID1 and RAID10 personalities require bio splitting,
2916 	 * RAID0/4/5/6 don't and process large discard bios properly.
2917 	 */
2918 	ti->split_discard_bios = !!(rs->md.level == 1 || rs->md.level == 10);
2919 	ti->num_discard_bios = 1;
2920 }
2921 
2922 /*
2923  * Construct a RAID0/1/10/4/5/6 mapping:
2924  * Args:
2925  *	<raid_type> <#raid_params> <raid_params>{0,}	\
2926  *	<#raid_devs> [<meta_dev1> <dev1>]{1,}
2927  *
2928  * <raid_params> varies by <raid_type>.	 See 'parse_raid_params' for
2929  * details on possible <raid_params>.
2930  *
2931  * Userspace is free to initialize the metadata devices, hence the superblocks to
2932  * enforce recreation based on the passed in table parameters.
2933  *
2934  */
2935 static int raid_ctr(struct dm_target *ti, unsigned int argc, char **argv)
2936 {
2937 	int r;
2938 	bool resize;
2939 	struct raid_type *rt;
2940 	unsigned int num_raid_params, num_raid_devs;
2941 	sector_t calculated_dev_sectors, rdev_sectors;
2942 	struct raid_set *rs = NULL;
2943 	const char *arg;
2944 	struct rs_layout rs_layout;
2945 	struct dm_arg_set as = { argc, argv }, as_nrd;
2946 	struct dm_arg _args[] = {
2947 		{ 0, as.argc, "Cannot understand number of raid parameters" },
2948 		{ 1, 254, "Cannot understand number of raid devices parameters" }
2949 	};
2950 
2951 	/* Must have <raid_type> */
2952 	arg = dm_shift_arg(&as);
2953 	if (!arg) {
2954 		ti->error = "No arguments";
2955 		return -EINVAL;
2956 	}
2957 
2958 	rt = get_raid_type(arg);
2959 	if (!rt) {
2960 		ti->error = "Unrecognised raid_type";
2961 		return -EINVAL;
2962 	}
2963 
2964 	/* Must have <#raid_params> */
2965 	if (dm_read_arg_group(_args, &as, &num_raid_params, &ti->error))
2966 		return -EINVAL;
2967 
2968 	/* number of raid device tupples <meta_dev data_dev> */
2969 	as_nrd = as;
2970 	dm_consume_args(&as_nrd, num_raid_params);
2971 	_args[1].max = (as_nrd.argc - 1) / 2;
2972 	if (dm_read_arg(_args + 1, &as_nrd, &num_raid_devs, &ti->error))
2973 		return -EINVAL;
2974 
2975 	if (!__within_range(num_raid_devs, 1, MAX_RAID_DEVICES)) {
2976 		ti->error = "Invalid number of supplied raid devices";
2977 		return -EINVAL;
2978 	}
2979 
2980 	rs = raid_set_alloc(ti, rt, num_raid_devs);
2981 	if (IS_ERR(rs))
2982 		return PTR_ERR(rs);
2983 
2984 	r = parse_raid_params(rs, &as, num_raid_params);
2985 	if (r)
2986 		goto bad;
2987 
2988 	r = parse_dev_params(rs, &as);
2989 	if (r)
2990 		goto bad;
2991 
2992 	rs->md.sync_super = super_sync;
2993 
2994 	/*
2995 	 * Calculate ctr requested array and device sizes to allow
2996 	 * for superblock analysis needing device sizes defined.
2997 	 *
2998 	 * Any existing superblock will overwrite the array and device sizes
2999 	 */
3000 	r = rs_set_dev_and_array_sectors(rs, false);
3001 	if (r)
3002 		goto bad;
3003 
3004 	calculated_dev_sectors = rs->md.dev_sectors;
3005 
3006 	/*
3007 	 * Backup any new raid set level, layout, ...
3008 	 * requested to be able to compare to superblock
3009 	 * members for conversion decisions.
3010 	 */
3011 	rs_config_backup(rs, &rs_layout);
3012 
3013 	r = analyse_superblocks(ti, rs);
3014 	if (r)
3015 		goto bad;
3016 
3017 	rdev_sectors = __rdev_sectors(rs);
3018 	if (!rdev_sectors) {
3019 		ti->error = "Invalid rdev size";
3020 		r = -EINVAL;
3021 		goto bad;
3022 	}
3023 
3024 	resize = calculated_dev_sectors != rdev_sectors;
3025 
3026 	INIT_WORK(&rs->md.event_work, do_table_event);
3027 	ti->private = rs;
3028 	ti->num_flush_bios = 1;
3029 
3030 	/* Restore any requested new layout for conversion decision */
3031 	rs_config_restore(rs, &rs_layout);
3032 
3033 	/*
3034 	 * Now that we have any superblock metadata available,
3035 	 * check for new, recovering, reshaping, to be taken over,
3036 	 * to be reshaped or an existing, unchanged raid set to
3037 	 * run in sequence.
3038 	 */
3039 	if (test_bit(MD_ARRAY_FIRST_USE, &rs->md.flags)) {
3040 		/* A new raid6 set has to be recovered to ensure proper parity and Q-Syndrome */
3041 		if (rs_is_raid6(rs) &&
3042 		    test_bit(__CTR_FLAG_NOSYNC, &rs->ctr_flags)) {
3043 			ti->error = "'nosync' not allowed for new raid6 set";
3044 			r = -EINVAL;
3045 			goto bad;
3046 		}
3047 		rs_setup_recovery(rs, 0);
3048 		set_bit(RT_FLAG_UPDATE_SBS, &rs->runtime_flags);
3049 		rs_set_new(rs);
3050 	} else if (rs_is_recovering(rs)) {
3051 		/* A recovering raid set may be resized */
3052 		; /* skip setup rs */
3053 	} else if (rs_is_reshaping(rs)) {
3054 		/* Have to reject size change request during reshape */
3055 		if (resize) {
3056 			ti->error = "Can't resize a reshaping raid set";
3057 			r = -EPERM;
3058 			goto bad;
3059 		}
3060 		/* skip setup rs */
3061 	} else if (rs_takeover_requested(rs)) {
3062 		if (rs_is_reshaping(rs)) {
3063 			ti->error = "Can't takeover a reshaping raid set";
3064 			r = -EPERM;
3065 			goto bad;
3066 		}
3067 
3068 		/* We can't takeover a journaled raid4/5/6 */
3069 		if (test_bit(__CTR_FLAG_JOURNAL_DEV, &rs->ctr_flags)) {
3070 			ti->error = "Can't takeover a journaled raid4/5/6 set";
3071 			r = -EPERM;
3072 			goto bad;
3073 		}
3074 
3075 		/*
3076 		 * If a takeover is needed, userspace sets any additional
3077 		 * devices to rebuild and we can check for a valid request here.
3078 		 *
3079 		 * If acceptible, set the level to the new requested
3080 		 * one, prohibit requesting recovery, allow the raid
3081 		 * set to run and store superblocks during resume.
3082 		 */
3083 		r = rs_check_takeover(rs);
3084 		if (r)
3085 			goto bad;
3086 
3087 		r = rs_setup_takeover(rs);
3088 		if (r)
3089 			goto bad;
3090 
3091 		set_bit(RT_FLAG_UPDATE_SBS, &rs->runtime_flags);
3092 		/* Takeover ain't recovery, so disable recovery */
3093 		rs_setup_recovery(rs, MaxSector);
3094 		rs_set_new(rs);
3095 	} else if (rs_reshape_requested(rs)) {
3096 		/*
3097 		 * No need to check for 'ongoing' takeover here, because takeover
3098 		 * is an instant operation as oposed to an ongoing reshape.
3099 		 */
3100 
3101 		/* We can't reshape a journaled raid4/5/6 */
3102 		if (test_bit(__CTR_FLAG_JOURNAL_DEV, &rs->ctr_flags)) {
3103 			ti->error = "Can't reshape a journaled raid4/5/6 set";
3104 			r = -EPERM;
3105 			goto bad;
3106 		}
3107 
3108 		/*
3109 		  * We can only prepare for a reshape here, because the
3110 		  * raid set needs to run to provide the repective reshape
3111 		  * check functions via its MD personality instance.
3112 		  *
3113 		  * So do the reshape check after md_run() succeeded.
3114 		  */
3115 		r = rs_prepare_reshape(rs);
3116 		if (r)
3117 			return r;
3118 
3119 		/* Reshaping ain't recovery, so disable recovery */
3120 		rs_setup_recovery(rs, MaxSector);
3121 		rs_set_cur(rs);
3122 	} else {
3123 		/* May not set recovery when a device rebuild is requested */
3124 		if (test_bit(__CTR_FLAG_REBUILD, &rs->ctr_flags)) {
3125 			rs_setup_recovery(rs, MaxSector);
3126 			set_bit(RT_FLAG_UPDATE_SBS, &rs->runtime_flags);
3127 		} else
3128 			rs_setup_recovery(rs, test_bit(__CTR_FLAG_SYNC, &rs->ctr_flags) ?
3129 					      0 : (resize ? calculated_dev_sectors : MaxSector));
3130 		rs_set_cur(rs);
3131 	}
3132 
3133 	/* If constructor requested it, change data and new_data offsets */
3134 	r = rs_adjust_data_offsets(rs);
3135 	if (r)
3136 		goto bad;
3137 
3138 	/* Start raid set read-only and assumed clean to change in raid_resume() */
3139 	rs->md.ro = 1;
3140 	rs->md.in_sync = 1;
3141 	set_bit(MD_RECOVERY_FROZEN, &rs->md.recovery);
3142 
3143 	/* Has to be held on running the array */
3144 	mddev_lock_nointr(&rs->md);
3145 	r = md_run(&rs->md);
3146 	rs->md.in_sync = 0; /* Assume already marked dirty */
3147 
3148 	if (r) {
3149 		ti->error = "Failed to run raid array";
3150 		mddev_unlock(&rs->md);
3151 		goto bad;
3152 	}
3153 
3154 	rs->callbacks.congested_fn = raid_is_congested;
3155 	dm_table_add_target_callbacks(ti->table, &rs->callbacks);
3156 
3157 	/* If raid4/5/6 journal mode explictely requested (only possible with journal dev) -> set it */
3158 	if (test_bit(__CTR_FLAG_JOURNAL_MODE, &rs->ctr_flags)) {
3159 		r = r5c_journal_mode_set(&rs->md, rs->journal_dev.mode);
3160 		if (r) {
3161 			ti->error = "Failed to set raid4/5/6 journal mode";
3162 			mddev_unlock(&rs->md);
3163 			goto bad_journal_mode_set;
3164 		}
3165 	}
3166 
3167 	mddev_suspend(&rs->md);
3168 	set_bit(RT_FLAG_RS_SUSPENDED, &rs->runtime_flags);
3169 
3170 	/* Try to adjust the raid4/5/6 stripe cache size to the stripe size */
3171 	if (rs_is_raid456(rs)) {
3172 		r = rs_set_raid456_stripe_cache(rs);
3173 		if (r)
3174 			goto bad_stripe_cache;
3175 	}
3176 
3177 	/* Now do an early reshape check */
3178 	if (test_bit(RT_FLAG_RESHAPE_RS, &rs->runtime_flags)) {
3179 		r = rs_check_reshape(rs);
3180 		if (r)
3181 			goto bad_check_reshape;
3182 
3183 		/* Restore new, ctr requested layout to perform check */
3184 		rs_config_restore(rs, &rs_layout);
3185 
3186 		if (rs->md.pers->start_reshape) {
3187 			r = rs->md.pers->check_reshape(&rs->md);
3188 			if (r) {
3189 				ti->error = "Reshape check failed";
3190 				goto bad_check_reshape;
3191 			}
3192 		}
3193 	}
3194 
3195 	/* Disable/enable discard support on raid set. */
3196 	configure_discard_support(rs);
3197 
3198 	mddev_unlock(&rs->md);
3199 	return 0;
3200 
3201 bad_journal_mode_set:
3202 bad_stripe_cache:
3203 bad_check_reshape:
3204 	md_stop(&rs->md);
3205 bad:
3206 	raid_set_free(rs);
3207 
3208 	return r;
3209 }
3210 
3211 static void raid_dtr(struct dm_target *ti)
3212 {
3213 	struct raid_set *rs = ti->private;
3214 
3215 	list_del_init(&rs->callbacks.list);
3216 	md_stop(&rs->md);
3217 	raid_set_free(rs);
3218 }
3219 
3220 static int raid_map(struct dm_target *ti, struct bio *bio)
3221 {
3222 	struct raid_set *rs = ti->private;
3223 	struct mddev *mddev = &rs->md;
3224 
3225 	/*
3226 	 * If we're reshaping to add disk(s)), ti->len and
3227 	 * mddev->array_sectors will differ during the process
3228 	 * (ti->len > mddev->array_sectors), so we have to requeue
3229 	 * bios with addresses > mddev->array_sectors here or
3230 	 * there will occur accesses past EOD of the component
3231 	 * data images thus erroring the raid set.
3232 	 */
3233 	if (unlikely(bio_end_sector(bio) > mddev->array_sectors))
3234 		return DM_MAPIO_REQUEUE;
3235 
3236 	md_handle_request(mddev, bio);
3237 
3238 	return DM_MAPIO_SUBMITTED;
3239 }
3240 
3241 /* Return string describing the current sync action of @mddev */
3242 static const char *decipher_sync_action(struct mddev *mddev)
3243 {
3244 	if (test_bit(MD_RECOVERY_FROZEN, &mddev->recovery))
3245 		return "frozen";
3246 
3247 	if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery) ||
3248 	    (!mddev->ro && test_bit(MD_RECOVERY_NEEDED, &mddev->recovery))) {
3249 		if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery))
3250 			return "reshape";
3251 
3252 		if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) {
3253 			if (!test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery))
3254 				return "resync";
3255 			else if (test_bit(MD_RECOVERY_CHECK, &mddev->recovery))
3256 				return "check";
3257 			return "repair";
3258 		}
3259 
3260 		if (test_bit(MD_RECOVERY_RECOVER, &mddev->recovery))
3261 			return "recover";
3262 	}
3263 
3264 	return "idle";
3265 }
3266 
3267 /*
3268  * Return status string for @rdev
3269  *
3270  * Status characters:
3271  *
3272  *  'D' = Dead/Failed raid set component or raid4/5/6 journal device
3273  *  'a' = Alive but not in-sync raid set component _or_ alive raid4/5/6 'write_back' journal device
3274  *  'A' = Alive and in-sync raid set component _or_ alive raid4/5/6 'write_through' journal device
3275  *  '-' = Non-existing device (i.e. uspace passed '- -' into the ctr)
3276  */
3277 static const char *__raid_dev_status(struct raid_set *rs, struct md_rdev *rdev, bool array_in_sync)
3278 {
3279 	if (!rdev->bdev)
3280 		return "-";
3281 	else if (test_bit(Faulty, &rdev->flags))
3282 		return "D";
3283 	else if (test_bit(Journal, &rdev->flags))
3284 		return (rs->journal_dev.mode == R5C_JOURNAL_MODE_WRITE_THROUGH) ? "A" : "a";
3285 	else if (!array_in_sync || !test_bit(In_sync, &rdev->flags))
3286 		return "a";
3287 	else
3288 		return "A";
3289 }
3290 
3291 /* Helper to return resync/reshape progress for @rs and @array_in_sync */
3292 static sector_t rs_get_progress(struct raid_set *rs,
3293 				sector_t resync_max_sectors, bool *array_in_sync)
3294 {
3295 	sector_t r, curr_resync_completed;
3296 	struct mddev *mddev = &rs->md;
3297 
3298 	curr_resync_completed = mddev->curr_resync_completed ?: mddev->recovery_cp;
3299 	*array_in_sync = false;
3300 
3301 	if (rs_is_raid0(rs)) {
3302 		r = resync_max_sectors;
3303 		*array_in_sync = true;
3304 
3305 	} else {
3306 		r = mddev->reshape_position;
3307 
3308 		/* Reshape is relative to the array size */
3309 		if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery) ||
3310 		    r != MaxSector) {
3311 			if (r == MaxSector) {
3312 				*array_in_sync = true;
3313 				r = resync_max_sectors;
3314 			} else {
3315 				/* Got to reverse on backward reshape */
3316 				if (mddev->reshape_backwards)
3317 					r = mddev->array_sectors - r;
3318 
3319 				/* Devide by # of data stripes */
3320 				sector_div(r, mddev_data_stripes(rs));
3321 			}
3322 
3323 		/* Sync is relative to the component device size */
3324 		} else if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery))
3325 			r = curr_resync_completed;
3326 		else
3327 			r = mddev->recovery_cp;
3328 
3329 		if ((r == MaxSector) ||
3330 		    (test_bit(MD_RECOVERY_DONE, &mddev->recovery) &&
3331 		     (mddev->curr_resync_completed == resync_max_sectors))) {
3332 			/*
3333 			 * Sync complete.
3334 			 */
3335 			*array_in_sync = true;
3336 			r = resync_max_sectors;
3337 		} else if (test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery)) {
3338 			/*
3339 			 * If "check" or "repair" is occurring, the raid set has
3340 			 * undergone an initial sync and the health characters
3341 			 * should not be 'a' anymore.
3342 			 */
3343 			*array_in_sync = true;
3344 		} else {
3345 			struct md_rdev *rdev;
3346 
3347 			/*
3348 			 * The raid set may be doing an initial sync, or it may
3349 			 * be rebuilding individual components.	 If all the
3350 			 * devices are In_sync, then it is the raid set that is
3351 			 * being initialized.
3352 			 */
3353 			rdev_for_each(rdev, mddev)
3354 				if (!test_bit(Journal, &rdev->flags) &&
3355 				    !test_bit(In_sync, &rdev->flags))
3356 					*array_in_sync = true;
3357 #if 0
3358 			r = 0; /* HM FIXME: TESTME: https://bugzilla.redhat.com/show_bug.cgi?id=1210637 ? */
3359 #endif
3360 		}
3361 	}
3362 
3363 	return r;
3364 }
3365 
3366 /* Helper to return @dev name or "-" if !@dev */
3367 static const char *__get_dev_name(struct dm_dev *dev)
3368 {
3369 	return dev ? dev->name : "-";
3370 }
3371 
3372 static void raid_status(struct dm_target *ti, status_type_t type,
3373 			unsigned int status_flags, char *result, unsigned int maxlen)
3374 {
3375 	struct raid_set *rs = ti->private;
3376 	struct mddev *mddev = &rs->md;
3377 	struct r5conf *conf = mddev->private;
3378 	int i, max_nr_stripes = conf ? conf->max_nr_stripes : 0;
3379 	bool array_in_sync;
3380 	unsigned int raid_param_cnt = 1; /* at least 1 for chunksize */
3381 	unsigned int sz = 0;
3382 	unsigned int rebuild_disks;
3383 	unsigned int write_mostly_params = 0;
3384 	sector_t progress, resync_max_sectors, resync_mismatches;
3385 	const char *sync_action;
3386 	struct raid_type *rt;
3387 
3388 	switch (type) {
3389 	case STATUSTYPE_INFO:
3390 		/* *Should* always succeed */
3391 		rt = get_raid_type_by_ll(mddev->new_level, mddev->new_layout);
3392 		if (!rt)
3393 			return;
3394 
3395 		DMEMIT("%s %d ", rt->name, mddev->raid_disks);
3396 
3397 		/* Access most recent mddev properties for status output */
3398 		smp_rmb();
3399 		/* Get sensible max sectors even if raid set not yet started */
3400 		resync_max_sectors = test_bit(RT_FLAG_RS_PRERESUMED, &rs->runtime_flags) ?
3401 				      mddev->resync_max_sectors : mddev->dev_sectors;
3402 		progress = rs_get_progress(rs, resync_max_sectors, &array_in_sync);
3403 		resync_mismatches = (mddev->last_sync_action && !strcasecmp(mddev->last_sync_action, "check")) ?
3404 				    atomic64_read(&mddev->resync_mismatches) : 0;
3405 		sync_action = decipher_sync_action(&rs->md);
3406 
3407 		/* HM FIXME: do we want another state char for raid0? It shows 'D'/'A'/'-' now */
3408 		for (i = 0; i < rs->raid_disks; i++)
3409 			DMEMIT(__raid_dev_status(rs, &rs->dev[i].rdev, array_in_sync));
3410 
3411 		/*
3412 		 * In-sync/Reshape ratio:
3413 		 *  The in-sync ratio shows the progress of:
3414 		 *   - Initializing the raid set
3415 		 *   - Rebuilding a subset of devices of the raid set
3416 		 *  The user can distinguish between the two by referring
3417 		 *  to the status characters.
3418 		 *
3419 		 *  The reshape ratio shows the progress of
3420 		 *  changing the raid layout or the number of
3421 		 *  disks of a raid set
3422 		 */
3423 		DMEMIT(" %llu/%llu", (unsigned long long) progress,
3424 				     (unsigned long long) resync_max_sectors);
3425 
3426 		/*
3427 		 * v1.5.0+:
3428 		 *
3429 		 * Sync action:
3430 		 *   See Documentation/device-mapper/dm-raid.txt for
3431 		 *   information on each of these states.
3432 		 */
3433 		DMEMIT(" %s", sync_action);
3434 
3435 		/*
3436 		 * v1.5.0+:
3437 		 *
3438 		 * resync_mismatches/mismatch_cnt
3439 		 *   This field shows the number of discrepancies found when
3440 		 *   performing a "check" of the raid set.
3441 		 */
3442 		DMEMIT(" %llu", (unsigned long long) resync_mismatches);
3443 
3444 		/*
3445 		 * v1.9.0+:
3446 		 *
3447 		 * data_offset (needed for out of space reshaping)
3448 		 *   This field shows the data offset into the data
3449 		 *   image LV where the first stripes data starts.
3450 		 *
3451 		 * We keep data_offset equal on all raid disks of the set,
3452 		 * so retrieving it from the first raid disk is sufficient.
3453 		 */
3454 		DMEMIT(" %llu", (unsigned long long) rs->dev[0].rdev.data_offset);
3455 
3456 		/*
3457 		 * v1.10.0+:
3458 		 */
3459 		DMEMIT(" %s", test_bit(__CTR_FLAG_JOURNAL_DEV, &rs->ctr_flags) ?
3460 			      __raid_dev_status(rs, &rs->journal_dev.rdev, 0) : "-");
3461 		break;
3462 
3463 	case STATUSTYPE_TABLE:
3464 		/* Report the table line string you would use to construct this raid set */
3465 
3466 		/* Calculate raid parameter count */
3467 		for (i = 0; i < rs->raid_disks; i++)
3468 			if (test_bit(WriteMostly, &rs->dev[i].rdev.flags))
3469 				write_mostly_params += 2;
3470 		rebuild_disks = memweight(rs->rebuild_disks, DISKS_ARRAY_ELEMS * sizeof(*rs->rebuild_disks));
3471 		raid_param_cnt += rebuild_disks * 2 +
3472 				  write_mostly_params +
3473 				  hweight32(rs->ctr_flags & CTR_FLAG_OPTIONS_NO_ARGS) +
3474 				  hweight32(rs->ctr_flags & CTR_FLAG_OPTIONS_ONE_ARG) * 2 +
3475 				  (test_bit(__CTR_FLAG_JOURNAL_DEV, &rs->ctr_flags) ? 2 : 0) +
3476 				  (test_bit(__CTR_FLAG_JOURNAL_MODE, &rs->ctr_flags) ? 2 : 0);
3477 
3478 		/* Emit table line */
3479 		/* This has to be in the documented order for userspace! */
3480 		DMEMIT("%s %u %u", rs->raid_type->name, raid_param_cnt, mddev->new_chunk_sectors);
3481 		if (test_bit(__CTR_FLAG_SYNC, &rs->ctr_flags))
3482 			DMEMIT(" %s", dm_raid_arg_name_by_flag(CTR_FLAG_SYNC));
3483 		if (test_bit(__CTR_FLAG_NOSYNC, &rs->ctr_flags))
3484 			DMEMIT(" %s", dm_raid_arg_name_by_flag(CTR_FLAG_NOSYNC));
3485 		if (rebuild_disks)
3486 			for (i = 0; i < rs->raid_disks; i++)
3487 				if (test_bit(rs->dev[i].rdev.raid_disk, (void *) rs->rebuild_disks))
3488 					DMEMIT(" %s %u", dm_raid_arg_name_by_flag(CTR_FLAG_REBUILD),
3489 							 rs->dev[i].rdev.raid_disk);
3490 		if (test_bit(__CTR_FLAG_DAEMON_SLEEP, &rs->ctr_flags))
3491 			DMEMIT(" %s %lu", dm_raid_arg_name_by_flag(CTR_FLAG_DAEMON_SLEEP),
3492 					  mddev->bitmap_info.daemon_sleep);
3493 		if (test_bit(__CTR_FLAG_MIN_RECOVERY_RATE, &rs->ctr_flags))
3494 			DMEMIT(" %s %d", dm_raid_arg_name_by_flag(CTR_FLAG_MIN_RECOVERY_RATE),
3495 					 mddev->sync_speed_min);
3496 		if (test_bit(__CTR_FLAG_MAX_RECOVERY_RATE, &rs->ctr_flags))
3497 			DMEMIT(" %s %d", dm_raid_arg_name_by_flag(CTR_FLAG_MAX_RECOVERY_RATE),
3498 					 mddev->sync_speed_max);
3499 		if (write_mostly_params)
3500 			for (i = 0; i < rs->raid_disks; i++)
3501 				if (test_bit(WriteMostly, &rs->dev[i].rdev.flags))
3502 					DMEMIT(" %s %d", dm_raid_arg_name_by_flag(CTR_FLAG_WRITE_MOSTLY),
3503 					       rs->dev[i].rdev.raid_disk);
3504 		if (test_bit(__CTR_FLAG_MAX_WRITE_BEHIND, &rs->ctr_flags))
3505 			DMEMIT(" %s %lu", dm_raid_arg_name_by_flag(CTR_FLAG_MAX_WRITE_BEHIND),
3506 					  mddev->bitmap_info.max_write_behind);
3507 		if (test_bit(__CTR_FLAG_STRIPE_CACHE, &rs->ctr_flags))
3508 			DMEMIT(" %s %d", dm_raid_arg_name_by_flag(CTR_FLAG_STRIPE_CACHE),
3509 					 max_nr_stripes);
3510 		if (test_bit(__CTR_FLAG_REGION_SIZE, &rs->ctr_flags))
3511 			DMEMIT(" %s %llu", dm_raid_arg_name_by_flag(CTR_FLAG_REGION_SIZE),
3512 					   (unsigned long long) to_sector(mddev->bitmap_info.chunksize));
3513 		if (test_bit(__CTR_FLAG_RAID10_COPIES, &rs->ctr_flags))
3514 			DMEMIT(" %s %d", dm_raid_arg_name_by_flag(CTR_FLAG_RAID10_COPIES),
3515 					 raid10_md_layout_to_copies(mddev->layout));
3516 		if (test_bit(__CTR_FLAG_RAID10_FORMAT, &rs->ctr_flags))
3517 			DMEMIT(" %s %s", dm_raid_arg_name_by_flag(CTR_FLAG_RAID10_FORMAT),
3518 					 raid10_md_layout_to_format(mddev->layout));
3519 		if (test_bit(__CTR_FLAG_DELTA_DISKS, &rs->ctr_flags))
3520 			DMEMIT(" %s %d", dm_raid_arg_name_by_flag(CTR_FLAG_DELTA_DISKS),
3521 					 max(rs->delta_disks, mddev->delta_disks));
3522 		if (test_bit(__CTR_FLAG_DATA_OFFSET, &rs->ctr_flags))
3523 			DMEMIT(" %s %llu", dm_raid_arg_name_by_flag(CTR_FLAG_DATA_OFFSET),
3524 					   (unsigned long long) rs->data_offset);
3525 		if (test_bit(__CTR_FLAG_JOURNAL_DEV, &rs->ctr_flags))
3526 			DMEMIT(" %s %s", dm_raid_arg_name_by_flag(CTR_FLAG_JOURNAL_DEV),
3527 					__get_dev_name(rs->journal_dev.dev));
3528 		if (test_bit(__CTR_FLAG_JOURNAL_MODE, &rs->ctr_flags))
3529 			DMEMIT(" %s %s", dm_raid_arg_name_by_flag(CTR_FLAG_JOURNAL_MODE),
3530 					 md_journal_mode_to_dm_raid(rs->journal_dev.mode));
3531 		DMEMIT(" %d", rs->raid_disks);
3532 		for (i = 0; i < rs->raid_disks; i++)
3533 			DMEMIT(" %s %s", __get_dev_name(rs->dev[i].meta_dev),
3534 					 __get_dev_name(rs->dev[i].data_dev));
3535 	}
3536 }
3537 
3538 static int raid_message(struct dm_target *ti, unsigned int argc, char **argv)
3539 {
3540 	struct raid_set *rs = ti->private;
3541 	struct mddev *mddev = &rs->md;
3542 
3543 	if (!mddev->pers || !mddev->pers->sync_request)
3544 		return -EINVAL;
3545 
3546 	if (!strcasecmp(argv[0], "frozen"))
3547 		set_bit(MD_RECOVERY_FROZEN, &mddev->recovery);
3548 	else
3549 		clear_bit(MD_RECOVERY_FROZEN, &mddev->recovery);
3550 
3551 	if (!strcasecmp(argv[0], "idle") || !strcasecmp(argv[0], "frozen")) {
3552 		if (mddev->sync_thread) {
3553 			set_bit(MD_RECOVERY_INTR, &mddev->recovery);
3554 			md_reap_sync_thread(mddev);
3555 		}
3556 	} else if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery) ||
3557 		   test_bit(MD_RECOVERY_NEEDED, &mddev->recovery))
3558 		return -EBUSY;
3559 	else if (!strcasecmp(argv[0], "resync"))
3560 		; /* MD_RECOVERY_NEEDED set below */
3561 	else if (!strcasecmp(argv[0], "recover"))
3562 		set_bit(MD_RECOVERY_RECOVER, &mddev->recovery);
3563 	else {
3564 		if (!strcasecmp(argv[0], "check")) {
3565 			set_bit(MD_RECOVERY_CHECK, &mddev->recovery);
3566 			set_bit(MD_RECOVERY_REQUESTED, &mddev->recovery);
3567 			set_bit(MD_RECOVERY_SYNC, &mddev->recovery);
3568 		} else if (!strcasecmp(argv[0], "repair")) {
3569 			set_bit(MD_RECOVERY_REQUESTED, &mddev->recovery);
3570 			set_bit(MD_RECOVERY_SYNC, &mddev->recovery);
3571 		} else
3572 			return -EINVAL;
3573 	}
3574 	if (mddev->ro == 2) {
3575 		/* A write to sync_action is enough to justify
3576 		 * canceling read-auto mode
3577 		 */
3578 		mddev->ro = 0;
3579 		if (!mddev->suspended && mddev->sync_thread)
3580 			md_wakeup_thread(mddev->sync_thread);
3581 	}
3582 	set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
3583 	if (!mddev->suspended && mddev->thread)
3584 		md_wakeup_thread(mddev->thread);
3585 
3586 	return 0;
3587 }
3588 
3589 static int raid_iterate_devices(struct dm_target *ti,
3590 				iterate_devices_callout_fn fn, void *data)
3591 {
3592 	struct raid_set *rs = ti->private;
3593 	unsigned int i;
3594 	int r = 0;
3595 
3596 	for (i = 0; !r && i < rs->md.raid_disks; i++)
3597 		if (rs->dev[i].data_dev)
3598 			r = fn(ti,
3599 				 rs->dev[i].data_dev,
3600 				 0, /* No offset on data devs */
3601 				 rs->md.dev_sectors,
3602 				 data);
3603 
3604 	return r;
3605 }
3606 
3607 static void raid_io_hints(struct dm_target *ti, struct queue_limits *limits)
3608 {
3609 	struct raid_set *rs = ti->private;
3610 	unsigned int chunk_size = to_bytes(rs->md.chunk_sectors);
3611 
3612 	blk_limits_io_min(limits, chunk_size);
3613 	blk_limits_io_opt(limits, chunk_size * mddev_data_stripes(rs));
3614 }
3615 
3616 static void raid_presuspend(struct dm_target *ti)
3617 {
3618 	struct raid_set *rs = ti->private;
3619 
3620 	md_stop_writes(&rs->md);
3621 }
3622 
3623 static void raid_postsuspend(struct dm_target *ti)
3624 {
3625 	struct raid_set *rs = ti->private;
3626 
3627 	if (!test_and_set_bit(RT_FLAG_RS_SUSPENDED, &rs->runtime_flags)) {
3628 		mddev_lock_nointr(&rs->md);
3629 		mddev_suspend(&rs->md);
3630 		mddev_unlock(&rs->md);
3631 	}
3632 
3633 	rs->md.ro = 1;
3634 }
3635 
3636 static void attempt_restore_of_faulty_devices(struct raid_set *rs)
3637 {
3638 	int i;
3639 	uint64_t cleared_failed_devices[DISKS_ARRAY_ELEMS];
3640 	unsigned long flags;
3641 	bool cleared = false;
3642 	struct dm_raid_superblock *sb;
3643 	struct mddev *mddev = &rs->md;
3644 	struct md_rdev *r;
3645 
3646 	/* RAID personalities have to provide hot add/remove methods or we need to bail out. */
3647 	if (!mddev->pers || !mddev->pers->hot_add_disk || !mddev->pers->hot_remove_disk)
3648 		return;
3649 
3650 	memset(cleared_failed_devices, 0, sizeof(cleared_failed_devices));
3651 
3652 	for (i = 0; i < mddev->raid_disks; i++) {
3653 		r = &rs->dev[i].rdev;
3654 		/* HM FIXME: enhance journal device recovery processing */
3655 		if (test_bit(Journal, &r->flags))
3656 			continue;
3657 
3658 		if (test_bit(Faulty, &r->flags) &&
3659 		    r->meta_bdev && !read_disk_sb(r, r->sb_size, true)) {
3660 			DMINFO("Faulty %s device #%d has readable super block."
3661 			       "  Attempting to revive it.",
3662 			       rs->raid_type->name, i);
3663 
3664 			/*
3665 			 * Faulty bit may be set, but sometimes the array can
3666 			 * be suspended before the personalities can respond
3667 			 * by removing the device from the array (i.e. calling
3668 			 * 'hot_remove_disk').	If they haven't yet removed
3669 			 * the failed device, its 'raid_disk' number will be
3670 			 * '>= 0' - meaning we must call this function
3671 			 * ourselves.
3672 			 */
3673 			flags = r->flags;
3674 			clear_bit(In_sync, &r->flags); /* Mandatory for hot remove. */
3675 			if (r->raid_disk >= 0) {
3676 				if (mddev->pers->hot_remove_disk(mddev, r)) {
3677 					/* Failed to revive this device, try next */
3678 					r->flags = flags;
3679 					continue;
3680 				}
3681 			} else
3682 				r->raid_disk = r->saved_raid_disk = i;
3683 
3684 			clear_bit(Faulty, &r->flags);
3685 			clear_bit(WriteErrorSeen, &r->flags);
3686 
3687 			if (mddev->pers->hot_add_disk(mddev, r)) {
3688 				/* Failed to revive this device, try next */
3689 				r->raid_disk = r->saved_raid_disk = -1;
3690 				r->flags = flags;
3691 			} else {
3692 				clear_bit(In_sync, &r->flags);
3693 				r->recovery_offset = 0;
3694 				set_bit(i, (void *) cleared_failed_devices);
3695 				cleared = true;
3696 			}
3697 		}
3698 	}
3699 
3700 	/* If any failed devices could be cleared, update all sbs failed_devices bits */
3701 	if (cleared) {
3702 		uint64_t failed_devices[DISKS_ARRAY_ELEMS];
3703 
3704 		rdev_for_each(r, &rs->md) {
3705 			if (test_bit(Journal, &r->flags))
3706 				continue;
3707 
3708 			sb = page_address(r->sb_page);
3709 			sb_retrieve_failed_devices(sb, failed_devices);
3710 
3711 			for (i = 0; i < DISKS_ARRAY_ELEMS; i++)
3712 				failed_devices[i] &= ~cleared_failed_devices[i];
3713 
3714 			sb_update_failed_devices(sb, failed_devices);
3715 		}
3716 	}
3717 }
3718 
3719 static int __load_dirty_region_bitmap(struct raid_set *rs)
3720 {
3721 	int r = 0;
3722 
3723 	/* Try loading the bitmap unless "raid0", which does not have one */
3724 	if (!rs_is_raid0(rs) &&
3725 	    !test_and_set_bit(RT_FLAG_RS_BITMAP_LOADED, &rs->runtime_flags)) {
3726 		r = bitmap_load(&rs->md);
3727 		if (r)
3728 			DMERR("Failed to load bitmap");
3729 	}
3730 
3731 	return r;
3732 }
3733 
3734 /* Enforce updating all superblocks */
3735 static void rs_update_sbs(struct raid_set *rs)
3736 {
3737 	struct mddev *mddev = &rs->md;
3738 	int ro = mddev->ro;
3739 
3740 	set_bit(MD_SB_CHANGE_DEVS, &mddev->sb_flags);
3741 	mddev->ro = 0;
3742 	md_update_sb(mddev, 1);
3743 	mddev->ro = ro;
3744 }
3745 
3746 /*
3747  * Reshape changes raid algorithm of @rs to new one within personality
3748  * (e.g. raid6_zr -> raid6_nc), changes stripe size, adds/removes
3749  * disks from a raid set thus growing/shrinking it or resizes the set
3750  *
3751  * Call mddev_lock_nointr() before!
3752  */
3753 static int rs_start_reshape(struct raid_set *rs)
3754 {
3755 	int r;
3756 	struct mddev *mddev = &rs->md;
3757 	struct md_personality *pers = mddev->pers;
3758 
3759 	r = rs_setup_reshape(rs);
3760 	if (r)
3761 		return r;
3762 
3763 	/* Need to be resumed to be able to start reshape, recovery is frozen until raid_resume() though */
3764 	if (test_and_clear_bit(RT_FLAG_RS_SUSPENDED, &rs->runtime_flags))
3765 		mddev_resume(mddev);
3766 
3767 	/*
3768 	 * Check any reshape constraints enforced by the personalility
3769 	 *
3770 	 * May as well already kick the reshape off so that * pers->start_reshape() becomes optional.
3771 	 */
3772 	r = pers->check_reshape(mddev);
3773 	if (r) {
3774 		rs->ti->error = "pers->check_reshape() failed";
3775 		return r;
3776 	}
3777 
3778 	/*
3779 	 * Personality may not provide start reshape method in which
3780 	 * case check_reshape above has already covered everything
3781 	 */
3782 	if (pers->start_reshape) {
3783 		r = pers->start_reshape(mddev);
3784 		if (r) {
3785 			rs->ti->error = "pers->start_reshape() failed";
3786 			return r;
3787 		}
3788 	}
3789 
3790 	/* Suspend because a resume will happen in raid_resume() */
3791 	set_bit(RT_FLAG_RS_SUSPENDED, &rs->runtime_flags);
3792 	mddev_suspend(mddev);
3793 
3794 	/*
3795 	 * Now reshape got set up, update superblocks to
3796 	 * reflect the fact so that a table reload will
3797 	 * access proper superblock content in the ctr.
3798 	 */
3799 	rs_update_sbs(rs);
3800 
3801 	return 0;
3802 }
3803 
3804 static int raid_preresume(struct dm_target *ti)
3805 {
3806 	int r;
3807 	struct raid_set *rs = ti->private;
3808 	struct mddev *mddev = &rs->md;
3809 
3810 	/* This is a resume after a suspend of the set -> it's already started */
3811 	if (test_and_set_bit(RT_FLAG_RS_PRERESUMED, &rs->runtime_flags))
3812 		return 0;
3813 
3814 	/*
3815 	 * The superblocks need to be updated on disk if the
3816 	 * array is new or new devices got added (thus zeroed
3817 	 * out by userspace) or __load_dirty_region_bitmap
3818 	 * will overwrite them in core with old data or fail.
3819 	 */
3820 	if (test_bit(RT_FLAG_UPDATE_SBS, &rs->runtime_flags))
3821 		rs_update_sbs(rs);
3822 
3823 	/* Load the bitmap from disk unless raid0 */
3824 	r = __load_dirty_region_bitmap(rs);
3825 	if (r)
3826 		return r;
3827 
3828 	/* Resize bitmap to adjust to changed region size (aka MD bitmap chunksize) */
3829 	if (test_bit(RT_FLAG_RS_BITMAP_LOADED, &rs->runtime_flags) && mddev->bitmap &&
3830 	    mddev->bitmap_info.chunksize != to_bytes(rs->requested_bitmap_chunk_sectors)) {
3831 		r = bitmap_resize(mddev->bitmap, mddev->dev_sectors,
3832 				  to_bytes(rs->requested_bitmap_chunk_sectors), 0);
3833 		if (r)
3834 			DMERR("Failed to resize bitmap");
3835 	}
3836 
3837 	/* Check for any resize/reshape on @rs and adjust/initiate */
3838 	/* Be prepared for mddev_resume() in raid_resume() */
3839 	set_bit(MD_RECOVERY_FROZEN, &mddev->recovery);
3840 	if (mddev->recovery_cp && mddev->recovery_cp < MaxSector) {
3841 		set_bit(MD_RECOVERY_SYNC, &mddev->recovery);
3842 		mddev->resync_min = mddev->recovery_cp;
3843 	}
3844 
3845 	rs_set_capacity(rs);
3846 
3847 	/* Check for any reshape request unless new raid set */
3848 	if (test_and_clear_bit(RT_FLAG_RESHAPE_RS, &rs->runtime_flags)) {
3849 		/* Initiate a reshape. */
3850 		mddev_lock_nointr(mddev);
3851 		r = rs_start_reshape(rs);
3852 		mddev_unlock(mddev);
3853 		if (r)
3854 			DMWARN("Failed to check/start reshape, continuing without change");
3855 		r = 0;
3856 	}
3857 
3858 	return r;
3859 }
3860 
3861 static void raid_resume(struct dm_target *ti)
3862 {
3863 	struct raid_set *rs = ti->private;
3864 	struct mddev *mddev = &rs->md;
3865 
3866 	if (test_and_set_bit(RT_FLAG_RS_RESUMED, &rs->runtime_flags)) {
3867 		/*
3868 		 * A secondary resume while the device is active.
3869 		 * Take this opportunity to check whether any failed
3870 		 * devices are reachable again.
3871 		 */
3872 		attempt_restore_of_faulty_devices(rs);
3873 	}
3874 
3875 	mddev->ro = 0;
3876 	mddev->in_sync = 0;
3877 
3878 	/*
3879 	 * Keep the RAID set frozen if reshape/rebuild flags are set.
3880 	 * The RAID set is unfrozen once the next table load/resume,
3881 	 * which clears the reshape/rebuild flags, occurs.
3882 	 * This ensures that the constructor for the inactive table
3883 	 * retrieves an up-to-date reshape_position.
3884 	 */
3885 	if (!(rs->ctr_flags & RESUME_STAY_FROZEN_FLAGS))
3886 		clear_bit(MD_RECOVERY_FROZEN, &mddev->recovery);
3887 
3888 	if (test_and_clear_bit(RT_FLAG_RS_SUSPENDED, &rs->runtime_flags)) {
3889 		mddev_lock_nointr(mddev);
3890 		mddev_resume(mddev);
3891 		mddev_unlock(mddev);
3892 	}
3893 }
3894 
3895 static struct target_type raid_target = {
3896 	.name = "raid",
3897 	.version = {1, 13, 0},
3898 	.module = THIS_MODULE,
3899 	.ctr = raid_ctr,
3900 	.dtr = raid_dtr,
3901 	.map = raid_map,
3902 	.status = raid_status,
3903 	.message = raid_message,
3904 	.iterate_devices = raid_iterate_devices,
3905 	.io_hints = raid_io_hints,
3906 	.presuspend = raid_presuspend,
3907 	.postsuspend = raid_postsuspend,
3908 	.preresume = raid_preresume,
3909 	.resume = raid_resume,
3910 };
3911 
3912 static int __init dm_raid_init(void)
3913 {
3914 	DMINFO("Loading target version %u.%u.%u",
3915 	       raid_target.version[0],
3916 	       raid_target.version[1],
3917 	       raid_target.version[2]);
3918 	return dm_register_target(&raid_target);
3919 }
3920 
3921 static void __exit dm_raid_exit(void)
3922 {
3923 	dm_unregister_target(&raid_target);
3924 }
3925 
3926 module_init(dm_raid_init);
3927 module_exit(dm_raid_exit);
3928 
3929 module_param(devices_handle_discard_safely, bool, 0644);
3930 MODULE_PARM_DESC(devices_handle_discard_safely,
3931 		 "Set to Y if all devices in each array reliably return zeroes on reads from discarded regions");
3932 
3933 MODULE_DESCRIPTION(DM_NAME " raid0/1/10/4/5/6 target");
3934 MODULE_ALIAS("dm-raid0");
3935 MODULE_ALIAS("dm-raid1");
3936 MODULE_ALIAS("dm-raid10");
3937 MODULE_ALIAS("dm-raid4");
3938 MODULE_ALIAS("dm-raid5");
3939 MODULE_ALIAS("dm-raid6");
3940 MODULE_AUTHOR("Neil Brown <dm-devel@redhat.com>");
3941 MODULE_AUTHOR("Heinz Mauelshagen <dm-devel@redhat.com>");
3942 MODULE_LICENSE("GPL");
3943