xref: /openbmc/linux/drivers/md/dm-raid.c (revision 4da722ca)
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 "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 
212 /* Array elements of 64 bit needed for rebuild/failed disk bits */
213 #define DISKS_ARRAY_ELEMS ((MAX_RAID_DEVICES + (sizeof(uint64_t) * 8 - 1)) / sizeof(uint64_t) / 8)
214 
215 /*
216  * raid set level, layout and chunk sectors backup/restore
217  */
218 struct rs_layout {
219 	int new_level;
220 	int new_layout;
221 	int new_chunk_sectors;
222 };
223 
224 struct raid_set {
225 	struct dm_target *ti;
226 
227 	uint32_t bitmap_loaded;
228 	uint32_t stripe_cache_entries;
229 	unsigned long ctr_flags;
230 	unsigned long runtime_flags;
231 
232 	uint64_t rebuild_disks[DISKS_ARRAY_ELEMS];
233 
234 	int raid_disks;
235 	int delta_disks;
236 	int data_offset;
237 	int raid10_copies;
238 	int requested_bitmap_chunk_sectors;
239 
240 	struct mddev md;
241 	struct raid_type *raid_type;
242 	struct dm_target_callbacks callbacks;
243 
244 	/* Optional raid4/5/6 journal device */
245 	struct journal_dev {
246 		struct dm_dev *dev;
247 		struct md_rdev rdev;
248 		int mode;
249 	} journal_dev;
250 
251 	struct raid_dev dev[0];
252 };
253 
254 static void rs_config_backup(struct raid_set *rs, struct rs_layout *l)
255 {
256 	struct mddev *mddev = &rs->md;
257 
258 	l->new_level = mddev->new_level;
259 	l->new_layout = mddev->new_layout;
260 	l->new_chunk_sectors = mddev->new_chunk_sectors;
261 }
262 
263 static void rs_config_restore(struct raid_set *rs, struct rs_layout *l)
264 {
265 	struct mddev *mddev = &rs->md;
266 
267 	mddev->new_level = l->new_level;
268 	mddev->new_layout = l->new_layout;
269 	mddev->new_chunk_sectors = l->new_chunk_sectors;
270 }
271 
272 /* raid10 algorithms (i.e. formats) */
273 #define	ALGORITHM_RAID10_DEFAULT	0
274 #define	ALGORITHM_RAID10_NEAR		1
275 #define	ALGORITHM_RAID10_OFFSET		2
276 #define	ALGORITHM_RAID10_FAR		3
277 
278 /* Supported raid types and properties. */
279 static struct raid_type {
280 	const char *name;		/* RAID algorithm. */
281 	const char *descr;		/* Descriptor text for logging. */
282 	const unsigned int parity_devs;	/* # of parity devices. */
283 	const unsigned int minimal_devs;/* minimal # of devices in set. */
284 	const unsigned int level;	/* RAID level. */
285 	const unsigned int algorithm;	/* RAID algorithm. */
286 } raid_types[] = {
287 	{"raid0",	  "raid0 (striping)",			    0, 2, 0,  0 /* NONE */},
288 	{"raid1",	  "raid1 (mirroring)",			    0, 2, 1,  0 /* NONE */},
289 	{"raid10_far",	  "raid10 far (striped mirrors)",	    0, 2, 10, ALGORITHM_RAID10_FAR},
290 	{"raid10_offset", "raid10 offset (striped mirrors)",	    0, 2, 10, ALGORITHM_RAID10_OFFSET},
291 	{"raid10_near",	  "raid10 near (striped mirrors)",	    0, 2, 10, ALGORITHM_RAID10_NEAR},
292 	{"raid10",	  "raid10 (striped mirrors)",		    0, 2, 10, ALGORITHM_RAID10_DEFAULT},
293 	{"raid4",	  "raid4 (dedicated first parity disk)",    1, 2, 5,  ALGORITHM_PARITY_0}, /* raid4 layout = raid5_0 */
294 	{"raid5_n",	  "raid5 (dedicated last parity disk)",	    1, 2, 5,  ALGORITHM_PARITY_N},
295 	{"raid5_ls",	  "raid5 (left symmetric)",		    1, 2, 5,  ALGORITHM_LEFT_SYMMETRIC},
296 	{"raid5_rs",	  "raid5 (right symmetric)",		    1, 2, 5,  ALGORITHM_RIGHT_SYMMETRIC},
297 	{"raid5_la",	  "raid5 (left asymmetric)",		    1, 2, 5,  ALGORITHM_LEFT_ASYMMETRIC},
298 	{"raid5_ra",	  "raid5 (right asymmetric)",		    1, 2, 5,  ALGORITHM_RIGHT_ASYMMETRIC},
299 	{"raid6_zr",	  "raid6 (zero restart)",		    2, 4, 6,  ALGORITHM_ROTATING_ZERO_RESTART},
300 	{"raid6_nr",	  "raid6 (N restart)",			    2, 4, 6,  ALGORITHM_ROTATING_N_RESTART},
301 	{"raid6_nc",	  "raid6 (N continue)",			    2, 4, 6,  ALGORITHM_ROTATING_N_CONTINUE},
302 	{"raid6_n_6",	  "raid6 (dedicated parity/Q n/6)",	    2, 4, 6,  ALGORITHM_PARITY_N_6},
303 	{"raid6_ls_6",	  "raid6 (left symmetric dedicated Q 6)",   2, 4, 6,  ALGORITHM_LEFT_SYMMETRIC_6},
304 	{"raid6_rs_6",	  "raid6 (right symmetric dedicated Q 6)",  2, 4, 6,  ALGORITHM_RIGHT_SYMMETRIC_6},
305 	{"raid6_la_6",	  "raid6 (left asymmetric dedicated Q 6)",  2, 4, 6,  ALGORITHM_LEFT_ASYMMETRIC_6},
306 	{"raid6_ra_6",	  "raid6 (right asymmetric dedicated Q 6)", 2, 4, 6,  ALGORITHM_RIGHT_ASYMMETRIC_6}
307 };
308 
309 /* True, if @v is in inclusive range [@min, @max] */
310 static bool __within_range(long v, long min, long max)
311 {
312 	return v >= min && v <= max;
313 }
314 
315 /* All table line arguments are defined here */
316 static struct arg_name_flag {
317 	const unsigned long flag;
318 	const char *name;
319 } __arg_name_flags[] = {
320 	{ CTR_FLAG_SYNC, "sync"},
321 	{ CTR_FLAG_NOSYNC, "nosync"},
322 	{ CTR_FLAG_REBUILD, "rebuild"},
323 	{ CTR_FLAG_DAEMON_SLEEP, "daemon_sleep"},
324 	{ CTR_FLAG_MIN_RECOVERY_RATE, "min_recovery_rate"},
325 	{ CTR_FLAG_MAX_RECOVERY_RATE, "max_recovery_rate"},
326 	{ CTR_FLAG_MAX_WRITE_BEHIND, "max_write_behind"},
327 	{ CTR_FLAG_WRITE_MOSTLY, "write_mostly"},
328 	{ CTR_FLAG_STRIPE_CACHE, "stripe_cache"},
329 	{ CTR_FLAG_REGION_SIZE, "region_size"},
330 	{ CTR_FLAG_RAID10_COPIES, "raid10_copies"},
331 	{ CTR_FLAG_RAID10_FORMAT, "raid10_format"},
332 	{ CTR_FLAG_DATA_OFFSET, "data_offset"},
333 	{ CTR_FLAG_DELTA_DISKS, "delta_disks"},
334 	{ CTR_FLAG_RAID10_USE_NEAR_SETS, "raid10_use_near_sets"},
335 	{ CTR_FLAG_JOURNAL_DEV, "journal_dev" },
336 	{ CTR_FLAG_JOURNAL_MODE, "journal_mode" },
337 };
338 
339 /* Return argument name string for given @flag */
340 static const char *dm_raid_arg_name_by_flag(const uint32_t flag)
341 {
342 	if (hweight32(flag) == 1) {
343 		struct arg_name_flag *anf = __arg_name_flags + ARRAY_SIZE(__arg_name_flags);
344 
345 		while (anf-- > __arg_name_flags)
346 			if (flag & anf->flag)
347 				return anf->name;
348 
349 	} else
350 		DMERR("%s called with more than one flag!", __func__);
351 
352 	return NULL;
353 }
354 
355 /* Define correlation of raid456 journal cache modes and dm-raid target line parameters */
356 static struct {
357 	const int mode;
358 	const char *param;
359 } _raid456_journal_mode[] = {
360 	{ R5C_JOURNAL_MODE_WRITE_THROUGH , "writethrough" },
361 	{ R5C_JOURNAL_MODE_WRITE_BACK    , "writeback" }
362 };
363 
364 /* Return MD raid4/5/6 journal mode for dm @journal_mode one */
365 static int dm_raid_journal_mode_to_md(const char *mode)
366 {
367 	int m = ARRAY_SIZE(_raid456_journal_mode);
368 
369 	while (m--)
370 		if (!strcasecmp(mode, _raid456_journal_mode[m].param))
371 			return _raid456_journal_mode[m].mode;
372 
373 	return -EINVAL;
374 }
375 
376 /* Return dm-raid raid4/5/6 journal mode string for @mode */
377 static const char *md_journal_mode_to_dm_raid(const int mode)
378 {
379 	int m = ARRAY_SIZE(_raid456_journal_mode);
380 
381 	while (m--)
382 		if (mode == _raid456_journal_mode[m].mode)
383 			return _raid456_journal_mode[m].param;
384 
385 	return "unknown";
386 }
387 
388 /*
389  * Bool helpers to test for various raid levels of a raid set.
390  * It's level as reported by the superblock rather than
391  * the requested raid_type passed to the constructor.
392  */
393 /* Return true, if raid set in @rs is raid0 */
394 static bool rs_is_raid0(struct raid_set *rs)
395 {
396 	return !rs->md.level;
397 }
398 
399 /* Return true, if raid set in @rs is raid1 */
400 static bool rs_is_raid1(struct raid_set *rs)
401 {
402 	return rs->md.level == 1;
403 }
404 
405 /* Return true, if raid set in @rs is raid10 */
406 static bool rs_is_raid10(struct raid_set *rs)
407 {
408 	return rs->md.level == 10;
409 }
410 
411 /* Return true, if raid set in @rs is level 6 */
412 static bool rs_is_raid6(struct raid_set *rs)
413 {
414 	return rs->md.level == 6;
415 }
416 
417 /* Return true, if raid set in @rs is level 4, 5 or 6 */
418 static bool rs_is_raid456(struct raid_set *rs)
419 {
420 	return __within_range(rs->md.level, 4, 6);
421 }
422 
423 /* Return true, if raid set in @rs is reshapable */
424 static bool __is_raid10_far(int layout);
425 static bool rs_is_reshapable(struct raid_set *rs)
426 {
427 	return rs_is_raid456(rs) ||
428 	       (rs_is_raid10(rs) && !__is_raid10_far(rs->md.new_layout));
429 }
430 
431 /* Return true, if raid set in @rs is recovering */
432 static bool rs_is_recovering(struct raid_set *rs)
433 {
434 	return rs->md.recovery_cp < rs->md.dev_sectors;
435 }
436 
437 /* Return true, if raid set in @rs is reshaping */
438 static bool rs_is_reshaping(struct raid_set *rs)
439 {
440 	return rs->md.reshape_position != MaxSector;
441 }
442 
443 /*
444  * bool helpers to test for various raid levels of a raid type @rt
445  */
446 
447 /* Return true, if raid type in @rt is raid0 */
448 static bool rt_is_raid0(struct raid_type *rt)
449 {
450 	return !rt->level;
451 }
452 
453 /* Return true, if raid type in @rt is raid1 */
454 static bool rt_is_raid1(struct raid_type *rt)
455 {
456 	return rt->level == 1;
457 }
458 
459 /* Return true, if raid type in @rt is raid10 */
460 static bool rt_is_raid10(struct raid_type *rt)
461 {
462 	return rt->level == 10;
463 }
464 
465 /* Return true, if raid type in @rt is raid4/5 */
466 static bool rt_is_raid45(struct raid_type *rt)
467 {
468 	return __within_range(rt->level, 4, 5);
469 }
470 
471 /* Return true, if raid type in @rt is raid6 */
472 static bool rt_is_raid6(struct raid_type *rt)
473 {
474 	return rt->level == 6;
475 }
476 
477 /* Return true, if raid type in @rt is raid4/5/6 */
478 static bool rt_is_raid456(struct raid_type *rt)
479 {
480 	return __within_range(rt->level, 4, 6);
481 }
482 /* END: raid level bools */
483 
484 /* Return valid ctr flags for the raid level of @rs */
485 static unsigned long __valid_flags(struct raid_set *rs)
486 {
487 	if (rt_is_raid0(rs->raid_type))
488 		return RAID0_VALID_FLAGS;
489 	else if (rt_is_raid1(rs->raid_type))
490 		return RAID1_VALID_FLAGS;
491 	else if (rt_is_raid10(rs->raid_type))
492 		return RAID10_VALID_FLAGS;
493 	else if (rt_is_raid45(rs->raid_type))
494 		return RAID45_VALID_FLAGS;
495 	else if (rt_is_raid6(rs->raid_type))
496 		return RAID6_VALID_FLAGS;
497 
498 	return 0;
499 }
500 
501 /*
502  * Check for valid flags set on @rs
503  *
504  * Has to be called after parsing of the ctr flags!
505  */
506 static int rs_check_for_valid_flags(struct raid_set *rs)
507 {
508 	if (rs->ctr_flags & ~__valid_flags(rs)) {
509 		rs->ti->error = "Invalid flags combination";
510 		return -EINVAL;
511 	}
512 
513 	return 0;
514 }
515 
516 /* MD raid10 bit definitions and helpers */
517 #define RAID10_OFFSET			(1 << 16) /* stripes with data copies area adjacent on devices */
518 #define RAID10_BROCKEN_USE_FAR_SETS	(1 << 17) /* Broken in raid10.c: use sets instead of whole stripe rotation */
519 #define RAID10_USE_FAR_SETS		(1 << 18) /* Use sets instead of whole stripe rotation */
520 #define RAID10_FAR_COPIES_SHIFT		8	  /* raid10 # far copies shift (2nd byte of layout) */
521 
522 /* Return md raid10 near copies for @layout */
523 static unsigned int __raid10_near_copies(int layout)
524 {
525 	return layout & 0xFF;
526 }
527 
528 /* Return md raid10 far copies for @layout */
529 static unsigned int __raid10_far_copies(int layout)
530 {
531 	return __raid10_near_copies(layout >> RAID10_FAR_COPIES_SHIFT);
532 }
533 
534 /* Return true if md raid10 offset for @layout */
535 static bool __is_raid10_offset(int layout)
536 {
537 	return !!(layout & RAID10_OFFSET);
538 }
539 
540 /* Return true if md raid10 near for @layout */
541 static bool __is_raid10_near(int layout)
542 {
543 	return !__is_raid10_offset(layout) && __raid10_near_copies(layout) > 1;
544 }
545 
546 /* Return true if md raid10 far for @layout */
547 static bool __is_raid10_far(int layout)
548 {
549 	return !__is_raid10_offset(layout) && __raid10_far_copies(layout) > 1;
550 }
551 
552 /* Return md raid10 layout string for @layout */
553 static const char *raid10_md_layout_to_format(int layout)
554 {
555 	/*
556 	 * Bit 16 stands for "offset"
557 	 * (i.e. adjacent stripes hold copies)
558 	 *
559 	 * Refer to MD's raid10.c for details
560 	 */
561 	if (__is_raid10_offset(layout))
562 		return "offset";
563 
564 	if (__raid10_near_copies(layout) > 1)
565 		return "near";
566 
567 	WARN_ON(__raid10_far_copies(layout) < 2);
568 
569 	return "far";
570 }
571 
572 /* Return md raid10 algorithm for @name */
573 static int raid10_name_to_format(const char *name)
574 {
575 	if (!strcasecmp(name, "near"))
576 		return ALGORITHM_RAID10_NEAR;
577 	else if (!strcasecmp(name, "offset"))
578 		return ALGORITHM_RAID10_OFFSET;
579 	else if (!strcasecmp(name, "far"))
580 		return ALGORITHM_RAID10_FAR;
581 
582 	return -EINVAL;
583 }
584 
585 /* Return md raid10 copies for @layout */
586 static unsigned int raid10_md_layout_to_copies(int layout)
587 {
588 	return max(__raid10_near_copies(layout), __raid10_far_copies(layout));
589 }
590 
591 /* Return md raid10 format id for @format string */
592 static int raid10_format_to_md_layout(struct raid_set *rs,
593 				      unsigned int algorithm,
594 				      unsigned int copies)
595 {
596 	unsigned int n = 1, f = 1, r = 0;
597 
598 	/*
599 	 * MD resilienece flaw:
600 	 *
601 	 * enabling use_far_sets for far/offset formats causes copies
602 	 * to be colocated on the same devs together with their origins!
603 	 *
604 	 * -> disable it for now in the definition above
605 	 */
606 	if (algorithm == ALGORITHM_RAID10_DEFAULT ||
607 	    algorithm == ALGORITHM_RAID10_NEAR)
608 		n = copies;
609 
610 	else if (algorithm == ALGORITHM_RAID10_OFFSET) {
611 		f = copies;
612 		r = RAID10_OFFSET;
613 		if (!test_bit(__CTR_FLAG_RAID10_USE_NEAR_SETS, &rs->ctr_flags))
614 			r |= RAID10_USE_FAR_SETS;
615 
616 	} else if (algorithm == ALGORITHM_RAID10_FAR) {
617 		f = copies;
618 		r = !RAID10_OFFSET;
619 		if (!test_bit(__CTR_FLAG_RAID10_USE_NEAR_SETS, &rs->ctr_flags))
620 			r |= RAID10_USE_FAR_SETS;
621 
622 	} else
623 		return -EINVAL;
624 
625 	return r | (f << RAID10_FAR_COPIES_SHIFT) | n;
626 }
627 /* END: MD raid10 bit definitions and helpers */
628 
629 /* Check for any of the raid10 algorithms */
630 static bool __got_raid10(struct raid_type *rtp, const int layout)
631 {
632 	if (rtp->level == 10) {
633 		switch (rtp->algorithm) {
634 		case ALGORITHM_RAID10_DEFAULT:
635 		case ALGORITHM_RAID10_NEAR:
636 			return __is_raid10_near(layout);
637 		case ALGORITHM_RAID10_OFFSET:
638 			return __is_raid10_offset(layout);
639 		case ALGORITHM_RAID10_FAR:
640 			return __is_raid10_far(layout);
641 		default:
642 			break;
643 		}
644 	}
645 
646 	return false;
647 }
648 
649 /* Return raid_type for @name */
650 static struct raid_type *get_raid_type(const char *name)
651 {
652 	struct raid_type *rtp = raid_types + ARRAY_SIZE(raid_types);
653 
654 	while (rtp-- > raid_types)
655 		if (!strcasecmp(rtp->name, name))
656 			return rtp;
657 
658 	return NULL;
659 }
660 
661 /* Return raid_type for @name based derived from @level and @layout */
662 static struct raid_type *get_raid_type_by_ll(const int level, const int layout)
663 {
664 	struct raid_type *rtp = raid_types + ARRAY_SIZE(raid_types);
665 
666 	while (rtp-- > raid_types) {
667 		/* RAID10 special checks based on @layout flags/properties */
668 		if (rtp->level == level &&
669 		    (__got_raid10(rtp, layout) || rtp->algorithm == layout))
670 			return rtp;
671 	}
672 
673 	return NULL;
674 }
675 
676 /*
677  * Conditionally change bdev capacity of @rs
678  * in case of a disk add/remove reshape
679  */
680 static void rs_set_capacity(struct raid_set *rs)
681 {
682 	struct mddev *mddev = &rs->md;
683 	struct md_rdev *rdev;
684 	struct gendisk *gendisk = dm_disk(dm_table_get_md(rs->ti->table));
685 
686 	/*
687 	 * raid10 sets rdev->sector to the device size, which
688 	 * is unintended in case of out-of-place reshaping
689 	 */
690 	rdev_for_each(rdev, mddev)
691 		if (!test_bit(Journal, &rdev->flags))
692 			rdev->sectors = mddev->dev_sectors;
693 
694 	set_capacity(gendisk, mddev->array_sectors);
695 	revalidate_disk(gendisk);
696 }
697 
698 /*
699  * Set the mddev properties in @rs to the current
700  * ones retrieved from the freshest superblock
701  */
702 static void rs_set_cur(struct raid_set *rs)
703 {
704 	struct mddev *mddev = &rs->md;
705 
706 	mddev->new_level = mddev->level;
707 	mddev->new_layout = mddev->layout;
708 	mddev->new_chunk_sectors = mddev->chunk_sectors;
709 }
710 
711 /*
712  * Set the mddev properties in @rs to the new
713  * ones requested by the ctr
714  */
715 static void rs_set_new(struct raid_set *rs)
716 {
717 	struct mddev *mddev = &rs->md;
718 
719 	mddev->level = mddev->new_level;
720 	mddev->layout = mddev->new_layout;
721 	mddev->chunk_sectors = mddev->new_chunk_sectors;
722 	mddev->raid_disks = rs->raid_disks;
723 	mddev->delta_disks = 0;
724 }
725 
726 static struct raid_set *raid_set_alloc(struct dm_target *ti, struct raid_type *raid_type,
727 				       unsigned int raid_devs)
728 {
729 	unsigned int i;
730 	struct raid_set *rs;
731 
732 	if (raid_devs <= raid_type->parity_devs) {
733 		ti->error = "Insufficient number of devices";
734 		return ERR_PTR(-EINVAL);
735 	}
736 
737 	rs = kzalloc(sizeof(*rs) + raid_devs * sizeof(rs->dev[0]), GFP_KERNEL);
738 	if (!rs) {
739 		ti->error = "Cannot allocate raid context";
740 		return ERR_PTR(-ENOMEM);
741 	}
742 
743 	mddev_init(&rs->md);
744 
745 	rs->raid_disks = raid_devs;
746 	rs->delta_disks = 0;
747 
748 	rs->ti = ti;
749 	rs->raid_type = raid_type;
750 	rs->stripe_cache_entries = 256;
751 	rs->md.raid_disks = raid_devs;
752 	rs->md.level = raid_type->level;
753 	rs->md.new_level = rs->md.level;
754 	rs->md.layout = raid_type->algorithm;
755 	rs->md.new_layout = rs->md.layout;
756 	rs->md.delta_disks = 0;
757 	rs->md.recovery_cp = MaxSector;
758 
759 	for (i = 0; i < raid_devs; i++)
760 		md_rdev_init(&rs->dev[i].rdev);
761 
762 	/*
763 	 * Remaining items to be initialized by further RAID params:
764 	 *  rs->md.persistent
765 	 *  rs->md.external
766 	 *  rs->md.chunk_sectors
767 	 *  rs->md.new_chunk_sectors
768 	 *  rs->md.dev_sectors
769 	 */
770 
771 	return rs;
772 }
773 
774 static void raid_set_free(struct raid_set *rs)
775 {
776 	int i;
777 
778 	if (rs->journal_dev.dev) {
779 		md_rdev_clear(&rs->journal_dev.rdev);
780 		dm_put_device(rs->ti, rs->journal_dev.dev);
781 	}
782 
783 	for (i = 0; i < rs->raid_disks; i++) {
784 		if (rs->dev[i].meta_dev)
785 			dm_put_device(rs->ti, rs->dev[i].meta_dev);
786 		md_rdev_clear(&rs->dev[i].rdev);
787 		if (rs->dev[i].data_dev)
788 			dm_put_device(rs->ti, rs->dev[i].data_dev);
789 	}
790 
791 	kfree(rs);
792 }
793 
794 /*
795  * For every device we have two words
796  *  <meta_dev>: meta device name or '-' if missing
797  *  <data_dev>: data device name or '-' if missing
798  *
799  * The following are permitted:
800  *    - -
801  *    - <data_dev>
802  *    <meta_dev> <data_dev>
803  *
804  * The following is not allowed:
805  *    <meta_dev> -
806  *
807  * This code parses those words.  If there is a failure,
808  * the caller must use raid_set_free() to unwind the operations.
809  */
810 static int parse_dev_params(struct raid_set *rs, struct dm_arg_set *as)
811 {
812 	int i;
813 	int rebuild = 0;
814 	int metadata_available = 0;
815 	int r = 0;
816 	const char *arg;
817 
818 	/* Put off the number of raid devices argument to get to dev pairs */
819 	arg = dm_shift_arg(as);
820 	if (!arg)
821 		return -EINVAL;
822 
823 	for (i = 0; i < rs->raid_disks; i++) {
824 		rs->dev[i].rdev.raid_disk = i;
825 
826 		rs->dev[i].meta_dev = NULL;
827 		rs->dev[i].data_dev = NULL;
828 
829 		/*
830 		 * There are no offsets initially.
831 		 * Out of place reshape will set them accordingly.
832 		 */
833 		rs->dev[i].rdev.data_offset = 0;
834 		rs->dev[i].rdev.new_data_offset = 0;
835 		rs->dev[i].rdev.mddev = &rs->md;
836 
837 		arg = dm_shift_arg(as);
838 		if (!arg)
839 			return -EINVAL;
840 
841 		if (strcmp(arg, "-")) {
842 			r = dm_get_device(rs->ti, arg, dm_table_get_mode(rs->ti->table),
843 					  &rs->dev[i].meta_dev);
844 			if (r) {
845 				rs->ti->error = "RAID metadata device lookup failure";
846 				return r;
847 			}
848 
849 			rs->dev[i].rdev.sb_page = alloc_page(GFP_KERNEL);
850 			if (!rs->dev[i].rdev.sb_page) {
851 				rs->ti->error = "Failed to allocate superblock page";
852 				return -ENOMEM;
853 			}
854 		}
855 
856 		arg = dm_shift_arg(as);
857 		if (!arg)
858 			return -EINVAL;
859 
860 		if (!strcmp(arg, "-")) {
861 			if (!test_bit(In_sync, &rs->dev[i].rdev.flags) &&
862 			    (!rs->dev[i].rdev.recovery_offset)) {
863 				rs->ti->error = "Drive designated for rebuild not specified";
864 				return -EINVAL;
865 			}
866 
867 			if (rs->dev[i].meta_dev) {
868 				rs->ti->error = "No data device supplied with metadata device";
869 				return -EINVAL;
870 			}
871 
872 			continue;
873 		}
874 
875 		r = dm_get_device(rs->ti, arg, dm_table_get_mode(rs->ti->table),
876 				  &rs->dev[i].data_dev);
877 		if (r) {
878 			rs->ti->error = "RAID device lookup failure";
879 			return r;
880 		}
881 
882 		if (rs->dev[i].meta_dev) {
883 			metadata_available = 1;
884 			rs->dev[i].rdev.meta_bdev = rs->dev[i].meta_dev->bdev;
885 		}
886 		rs->dev[i].rdev.bdev = rs->dev[i].data_dev->bdev;
887 		list_add_tail(&rs->dev[i].rdev.same_set, &rs->md.disks);
888 		if (!test_bit(In_sync, &rs->dev[i].rdev.flags))
889 			rebuild++;
890 	}
891 
892 	if (rs->journal_dev.dev)
893 		list_add_tail(&rs->journal_dev.rdev.same_set, &rs->md.disks);
894 
895 	if (metadata_available) {
896 		rs->md.external = 0;
897 		rs->md.persistent = 1;
898 		rs->md.major_version = 2;
899 	} else if (rebuild && !rs->md.recovery_cp) {
900 		/*
901 		 * Without metadata, we will not be able to tell if the array
902 		 * is in-sync or not - we must assume it is not.  Therefore,
903 		 * it is impossible to rebuild a drive.
904 		 *
905 		 * Even if there is metadata, the on-disk information may
906 		 * indicate that the array is not in-sync and it will then
907 		 * fail at that time.
908 		 *
909 		 * User could specify 'nosync' option if desperate.
910 		 */
911 		rs->ti->error = "Unable to rebuild drive while array is not in-sync";
912 		return -EINVAL;
913 	}
914 
915 	return 0;
916 }
917 
918 /*
919  * validate_region_size
920  * @rs
921  * @region_size:  region size in sectors.  If 0, pick a size (4MiB default).
922  *
923  * Set rs->md.bitmap_info.chunksize (which really refers to 'region size').
924  * Ensure that (ti->len/region_size < 2^21) - required by MD bitmap.
925  *
926  * Returns: 0 on success, -EINVAL on failure.
927  */
928 static int validate_region_size(struct raid_set *rs, unsigned long region_size)
929 {
930 	unsigned long min_region_size = rs->ti->len / (1 << 21);
931 
932 	if (rs_is_raid0(rs))
933 		return 0;
934 
935 	if (!region_size) {
936 		/*
937 		 * Choose a reasonable default.	 All figures in sectors.
938 		 */
939 		if (min_region_size > (1 << 13)) {
940 			/* If not a power of 2, make it the next power of 2 */
941 			region_size = roundup_pow_of_two(min_region_size);
942 			DMINFO("Choosing default region size of %lu sectors",
943 			       region_size);
944 		} else {
945 			DMINFO("Choosing default region size of 4MiB");
946 			region_size = 1 << 13; /* sectors */
947 		}
948 	} else {
949 		/*
950 		 * Validate user-supplied value.
951 		 */
952 		if (region_size > rs->ti->len) {
953 			rs->ti->error = "Supplied region size is too large";
954 			return -EINVAL;
955 		}
956 
957 		if (region_size < min_region_size) {
958 			DMERR("Supplied region_size (%lu sectors) below minimum (%lu)",
959 			      region_size, min_region_size);
960 			rs->ti->error = "Supplied region size is too small";
961 			return -EINVAL;
962 		}
963 
964 		if (!is_power_of_2(region_size)) {
965 			rs->ti->error = "Region size is not a power of 2";
966 			return -EINVAL;
967 		}
968 
969 		if (region_size < rs->md.chunk_sectors) {
970 			rs->ti->error = "Region size is smaller than the chunk size";
971 			return -EINVAL;
972 		}
973 	}
974 
975 	/*
976 	 * Convert sectors to bytes.
977 	 */
978 	rs->md.bitmap_info.chunksize = to_bytes(region_size);
979 
980 	return 0;
981 }
982 
983 /*
984  * validate_raid_redundancy
985  * @rs
986  *
987  * Determine if there are enough devices in the array that haven't
988  * failed (or are being rebuilt) to form a usable array.
989  *
990  * Returns: 0 on success, -EINVAL on failure.
991  */
992 static int validate_raid_redundancy(struct raid_set *rs)
993 {
994 	unsigned int i, rebuild_cnt = 0;
995 	unsigned int rebuilds_per_group = 0, copies;
996 	unsigned int group_size, last_group_start;
997 
998 	for (i = 0; i < rs->md.raid_disks; i++)
999 		if (!test_bit(In_sync, &rs->dev[i].rdev.flags) ||
1000 		    !rs->dev[i].rdev.sb_page)
1001 			rebuild_cnt++;
1002 
1003 	switch (rs->raid_type->level) {
1004 	case 0:
1005 		break;
1006 	case 1:
1007 		if (rebuild_cnt >= rs->md.raid_disks)
1008 			goto too_many;
1009 		break;
1010 	case 4:
1011 	case 5:
1012 	case 6:
1013 		if (rebuild_cnt > rs->raid_type->parity_devs)
1014 			goto too_many;
1015 		break;
1016 	case 10:
1017 		copies = raid10_md_layout_to_copies(rs->md.new_layout);
1018 		if (rebuild_cnt < copies)
1019 			break;
1020 
1021 		/*
1022 		 * It is possible to have a higher rebuild count for RAID10,
1023 		 * as long as the failed devices occur in different mirror
1024 		 * groups (i.e. different stripes).
1025 		 *
1026 		 * When checking "near" format, make sure no adjacent devices
1027 		 * have failed beyond what can be handled.  In addition to the
1028 		 * simple case where the number of devices is a multiple of the
1029 		 * number of copies, we must also handle cases where the number
1030 		 * of devices is not a multiple of the number of copies.
1031 		 * E.g.	   dev1 dev2 dev3 dev4 dev5
1032 		 *	    A	 A    B	   B	C
1033 		 *	    C	 D    D	   E	E
1034 		 */
1035 		if (__is_raid10_near(rs->md.new_layout)) {
1036 			for (i = 0; i < rs->md.raid_disks; i++) {
1037 				if (!(i % copies))
1038 					rebuilds_per_group = 0;
1039 				if ((!rs->dev[i].rdev.sb_page ||
1040 				    !test_bit(In_sync, &rs->dev[i].rdev.flags)) &&
1041 				    (++rebuilds_per_group >= copies))
1042 					goto too_many;
1043 			}
1044 			break;
1045 		}
1046 
1047 		/*
1048 		 * When checking "far" and "offset" formats, we need to ensure
1049 		 * that the device that holds its copy is not also dead or
1050 		 * being rebuilt.  (Note that "far" and "offset" formats only
1051 		 * support two copies right now.  These formats also only ever
1052 		 * use the 'use_far_sets' variant.)
1053 		 *
1054 		 * This check is somewhat complicated by the need to account
1055 		 * for arrays that are not a multiple of (far) copies.	This
1056 		 * results in the need to treat the last (potentially larger)
1057 		 * set differently.
1058 		 */
1059 		group_size = (rs->md.raid_disks / copies);
1060 		last_group_start = (rs->md.raid_disks / group_size) - 1;
1061 		last_group_start *= group_size;
1062 		for (i = 0; i < rs->md.raid_disks; i++) {
1063 			if (!(i % copies) && !(i > last_group_start))
1064 				rebuilds_per_group = 0;
1065 			if ((!rs->dev[i].rdev.sb_page ||
1066 			     !test_bit(In_sync, &rs->dev[i].rdev.flags)) &&
1067 			    (++rebuilds_per_group >= copies))
1068 					goto too_many;
1069 		}
1070 		break;
1071 	default:
1072 		if (rebuild_cnt)
1073 			return -EINVAL;
1074 	}
1075 
1076 	return 0;
1077 
1078 too_many:
1079 	return -EINVAL;
1080 }
1081 
1082 /*
1083  * Possible arguments are...
1084  *	<chunk_size> [optional_args]
1085  *
1086  * Argument definitions
1087  *    <chunk_size>			The number of sectors per disk that
1088  *					will form the "stripe"
1089  *    [[no]sync]			Force or prevent recovery of the
1090  *					entire array
1091  *    [rebuild <idx>]			Rebuild the drive indicated by the index
1092  *    [daemon_sleep <ms>]		Time between bitmap daemon work to
1093  *					clear bits
1094  *    [min_recovery_rate <kB/sec/disk>]	Throttle RAID initialization
1095  *    [max_recovery_rate <kB/sec/disk>]	Throttle RAID initialization
1096  *    [write_mostly <idx>]		Indicate a write mostly drive via index
1097  *    [max_write_behind <sectors>]	See '-write-behind=' (man mdadm)
1098  *    [stripe_cache <sectors>]		Stripe cache size for higher RAIDs
1099  *    [region_size <sectors>]		Defines granularity of bitmap
1100  *    [journal_dev <dev>]		raid4/5/6 journaling deviice
1101  *    					(i.e. write hole closing log)
1102  *
1103  * RAID10-only options:
1104  *    [raid10_copies <# copies>]	Number of copies.  (Default: 2)
1105  *    [raid10_format <near|far|offset>] Layout algorithm.  (Default: near)
1106  */
1107 static int parse_raid_params(struct raid_set *rs, struct dm_arg_set *as,
1108 			     unsigned int num_raid_params)
1109 {
1110 	int value, raid10_format = ALGORITHM_RAID10_DEFAULT;
1111 	unsigned int raid10_copies = 2;
1112 	unsigned int i, write_mostly = 0;
1113 	unsigned int region_size = 0;
1114 	sector_t max_io_len;
1115 	const char *arg, *key;
1116 	struct raid_dev *rd;
1117 	struct raid_type *rt = rs->raid_type;
1118 
1119 	arg = dm_shift_arg(as);
1120 	num_raid_params--; /* Account for chunk_size argument */
1121 
1122 	if (kstrtoint(arg, 10, &value) < 0) {
1123 		rs->ti->error = "Bad numerical argument given for chunk_size";
1124 		return -EINVAL;
1125 	}
1126 
1127 	/*
1128 	 * First, parse the in-order required arguments
1129 	 * "chunk_size" is the only argument of this type.
1130 	 */
1131 	if (rt_is_raid1(rt)) {
1132 		if (value)
1133 			DMERR("Ignoring chunk size parameter for RAID 1");
1134 		value = 0;
1135 	} else if (!is_power_of_2(value)) {
1136 		rs->ti->error = "Chunk size must be a power of 2";
1137 		return -EINVAL;
1138 	} else if (value < 8) {
1139 		rs->ti->error = "Chunk size value is too small";
1140 		return -EINVAL;
1141 	}
1142 
1143 	rs->md.new_chunk_sectors = rs->md.chunk_sectors = value;
1144 
1145 	/*
1146 	 * We set each individual device as In_sync with a completed
1147 	 * 'recovery_offset'.  If there has been a device failure or
1148 	 * replacement then one of the following cases applies:
1149 	 *
1150 	 *   1) User specifies 'rebuild'.
1151 	 *	- Device is reset when param is read.
1152 	 *   2) A new device is supplied.
1153 	 *	- No matching superblock found, resets device.
1154 	 *   3) Device failure was transient and returns on reload.
1155 	 *	- Failure noticed, resets device for bitmap replay.
1156 	 *   4) Device hadn't completed recovery after previous failure.
1157 	 *	- Superblock is read and overrides recovery_offset.
1158 	 *
1159 	 * What is found in the superblocks of the devices is always
1160 	 * authoritative, unless 'rebuild' or '[no]sync' was specified.
1161 	 */
1162 	for (i = 0; i < rs->raid_disks; i++) {
1163 		set_bit(In_sync, &rs->dev[i].rdev.flags);
1164 		rs->dev[i].rdev.recovery_offset = MaxSector;
1165 	}
1166 
1167 	/*
1168 	 * Second, parse the unordered optional arguments
1169 	 */
1170 	for (i = 0; i < num_raid_params; i++) {
1171 		key = dm_shift_arg(as);
1172 		if (!key) {
1173 			rs->ti->error = "Not enough raid parameters given";
1174 			return -EINVAL;
1175 		}
1176 
1177 		if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_NOSYNC))) {
1178 			if (test_and_set_bit(__CTR_FLAG_NOSYNC, &rs->ctr_flags)) {
1179 				rs->ti->error = "Only one 'nosync' argument allowed";
1180 				return -EINVAL;
1181 			}
1182 			continue;
1183 		}
1184 		if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_SYNC))) {
1185 			if (test_and_set_bit(__CTR_FLAG_SYNC, &rs->ctr_flags)) {
1186 				rs->ti->error = "Only one 'sync' argument allowed";
1187 				return -EINVAL;
1188 			}
1189 			continue;
1190 		}
1191 		if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_RAID10_USE_NEAR_SETS))) {
1192 			if (test_and_set_bit(__CTR_FLAG_RAID10_USE_NEAR_SETS, &rs->ctr_flags)) {
1193 				rs->ti->error = "Only one 'raid10_use_new_sets' argument allowed";
1194 				return -EINVAL;
1195 			}
1196 			continue;
1197 		}
1198 
1199 		arg = dm_shift_arg(as);
1200 		i++; /* Account for the argument pairs */
1201 		if (!arg) {
1202 			rs->ti->error = "Wrong number of raid parameters given";
1203 			return -EINVAL;
1204 		}
1205 
1206 		/*
1207 		 * Parameters that take a string value are checked here.
1208 		 */
1209 		/* "raid10_format {near|offset|far} */
1210 		if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_RAID10_FORMAT))) {
1211 			if (test_and_set_bit(__CTR_FLAG_RAID10_FORMAT, &rs->ctr_flags)) {
1212 				rs->ti->error = "Only one 'raid10_format' argument pair allowed";
1213 				return -EINVAL;
1214 			}
1215 			if (!rt_is_raid10(rt)) {
1216 				rs->ti->error = "'raid10_format' is an invalid parameter for this RAID type";
1217 				return -EINVAL;
1218 			}
1219 			raid10_format = raid10_name_to_format(arg);
1220 			if (raid10_format < 0) {
1221 				rs->ti->error = "Invalid 'raid10_format' value given";
1222 				return raid10_format;
1223 			}
1224 			continue;
1225 		}
1226 
1227 		/* "journal_dev <dev>" */
1228 		if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_JOURNAL_DEV))) {
1229 			int r;
1230 			struct md_rdev *jdev;
1231 
1232 			if (test_and_set_bit(__CTR_FLAG_JOURNAL_DEV, &rs->ctr_flags)) {
1233 				rs->ti->error = "Only one raid4/5/6 set journaling device allowed";
1234 				return -EINVAL;
1235 			}
1236 			if (!rt_is_raid456(rt)) {
1237 				rs->ti->error = "'journal_dev' is an invalid parameter for this RAID type";
1238 				return -EINVAL;
1239 			}
1240 			r = dm_get_device(rs->ti, arg, dm_table_get_mode(rs->ti->table),
1241 					  &rs->journal_dev.dev);
1242 			if (r) {
1243 				rs->ti->error = "raid4/5/6 journal device lookup failure";
1244 				return r;
1245 			}
1246 			jdev = &rs->journal_dev.rdev;
1247 			md_rdev_init(jdev);
1248 			jdev->mddev = &rs->md;
1249 			jdev->bdev = rs->journal_dev.dev->bdev;
1250 			jdev->sectors = to_sector(i_size_read(jdev->bdev->bd_inode));
1251 			if (jdev->sectors < MIN_RAID456_JOURNAL_SPACE) {
1252 				rs->ti->error = "No space for raid4/5/6 journal";
1253 				return -ENOSPC;
1254 			}
1255 			rs->journal_dev.mode = R5C_JOURNAL_MODE_WRITE_THROUGH;
1256 			set_bit(Journal, &jdev->flags);
1257 			continue;
1258 		}
1259 
1260 		/* "journal_mode <mode>" ("journal_dev" mandatory!) */
1261 		if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_JOURNAL_MODE))) {
1262 			int r;
1263 
1264 			if (!test_bit(__CTR_FLAG_JOURNAL_DEV, &rs->ctr_flags)) {
1265 				rs->ti->error = "raid4/5/6 'journal_mode' is invalid without 'journal_dev'";
1266 				return -EINVAL;
1267 			}
1268 			if (test_and_set_bit(__CTR_FLAG_JOURNAL_MODE, &rs->ctr_flags)) {
1269 				rs->ti->error = "Only one raid4/5/6 'journal_mode' argument allowed";
1270 				return -EINVAL;
1271 			}
1272 			r = dm_raid_journal_mode_to_md(arg);
1273 			if (r < 0) {
1274 				rs->ti->error = "Invalid 'journal_mode' argument";
1275 				return r;
1276 			}
1277 			rs->journal_dev.mode = r;
1278 			continue;
1279 		}
1280 
1281 		/*
1282 		 * Parameters with number values from here on.
1283 		 */
1284 		if (kstrtoint(arg, 10, &value) < 0) {
1285 			rs->ti->error = "Bad numerical argument given in raid params";
1286 			return -EINVAL;
1287 		}
1288 
1289 		if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_REBUILD))) {
1290 			/*
1291 			 * "rebuild" is being passed in by userspace to provide
1292 			 * indexes of replaced devices and to set up additional
1293 			 * devices on raid level takeover.
1294 			 */
1295 			if (!__within_range(value, 0, rs->raid_disks - 1)) {
1296 				rs->ti->error = "Invalid rebuild index given";
1297 				return -EINVAL;
1298 			}
1299 
1300 			if (test_and_set_bit(value, (void *) rs->rebuild_disks)) {
1301 				rs->ti->error = "rebuild for this index already given";
1302 				return -EINVAL;
1303 			}
1304 
1305 			rd = rs->dev + value;
1306 			clear_bit(In_sync, &rd->rdev.flags);
1307 			clear_bit(Faulty, &rd->rdev.flags);
1308 			rd->rdev.recovery_offset = 0;
1309 			set_bit(__CTR_FLAG_REBUILD, &rs->ctr_flags);
1310 		} else if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_WRITE_MOSTLY))) {
1311 			if (!rt_is_raid1(rt)) {
1312 				rs->ti->error = "write_mostly option is only valid for RAID1";
1313 				return -EINVAL;
1314 			}
1315 
1316 			if (!__within_range(value, 0, rs->md.raid_disks - 1)) {
1317 				rs->ti->error = "Invalid write_mostly index given";
1318 				return -EINVAL;
1319 			}
1320 
1321 			write_mostly++;
1322 			set_bit(WriteMostly, &rs->dev[value].rdev.flags);
1323 			set_bit(__CTR_FLAG_WRITE_MOSTLY, &rs->ctr_flags);
1324 		} else if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_MAX_WRITE_BEHIND))) {
1325 			if (!rt_is_raid1(rt)) {
1326 				rs->ti->error = "max_write_behind option is only valid for RAID1";
1327 				return -EINVAL;
1328 			}
1329 
1330 			if (test_and_set_bit(__CTR_FLAG_MAX_WRITE_BEHIND, &rs->ctr_flags)) {
1331 				rs->ti->error = "Only one max_write_behind argument pair allowed";
1332 				return -EINVAL;
1333 			}
1334 
1335 			/*
1336 			 * In device-mapper, we specify things in sectors, but
1337 			 * MD records this value in kB
1338 			 */
1339 			value /= 2;
1340 			if (value > COUNTER_MAX) {
1341 				rs->ti->error = "Max write-behind limit out of range";
1342 				return -EINVAL;
1343 			}
1344 
1345 			rs->md.bitmap_info.max_write_behind = value;
1346 		} else if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_DAEMON_SLEEP))) {
1347 			if (test_and_set_bit(__CTR_FLAG_DAEMON_SLEEP, &rs->ctr_flags)) {
1348 				rs->ti->error = "Only one daemon_sleep argument pair allowed";
1349 				return -EINVAL;
1350 			}
1351 			if (!value || (value > MAX_SCHEDULE_TIMEOUT)) {
1352 				rs->ti->error = "daemon sleep period out of range";
1353 				return -EINVAL;
1354 			}
1355 			rs->md.bitmap_info.daemon_sleep = value;
1356 		} else if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_DATA_OFFSET))) {
1357 			/* Userspace passes new data_offset after having extended the the data image LV */
1358 			if (test_and_set_bit(__CTR_FLAG_DATA_OFFSET, &rs->ctr_flags)) {
1359 				rs->ti->error = "Only one data_offset argument pair allowed";
1360 				return -EINVAL;
1361 			}
1362 			/* Ensure sensible data offset */
1363 			if (value < 0 ||
1364 			    (value && (value < MIN_FREE_RESHAPE_SPACE || value % to_sector(PAGE_SIZE)))) {
1365 				rs->ti->error = "Bogus data_offset value";
1366 				return -EINVAL;
1367 			}
1368 			rs->data_offset = value;
1369 		} else if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_DELTA_DISKS))) {
1370 			/* Define the +/-# of disks to add to/remove from the given raid set */
1371 			if (test_and_set_bit(__CTR_FLAG_DELTA_DISKS, &rs->ctr_flags)) {
1372 				rs->ti->error = "Only one delta_disks argument pair allowed";
1373 				return -EINVAL;
1374 			}
1375 			/* Ensure MAX_RAID_DEVICES and raid type minimal_devs! */
1376 			if (!__within_range(abs(value), 1, MAX_RAID_DEVICES - rt->minimal_devs)) {
1377 				rs->ti->error = "Too many delta_disk requested";
1378 				return -EINVAL;
1379 			}
1380 
1381 			rs->delta_disks = value;
1382 		} else if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_STRIPE_CACHE))) {
1383 			if (test_and_set_bit(__CTR_FLAG_STRIPE_CACHE, &rs->ctr_flags)) {
1384 				rs->ti->error = "Only one stripe_cache argument pair allowed";
1385 				return -EINVAL;
1386 			}
1387 
1388 			if (!rt_is_raid456(rt)) {
1389 				rs->ti->error = "Inappropriate argument: stripe_cache";
1390 				return -EINVAL;
1391 			}
1392 
1393 			rs->stripe_cache_entries = value;
1394 		} else if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_MIN_RECOVERY_RATE))) {
1395 			if (test_and_set_bit(__CTR_FLAG_MIN_RECOVERY_RATE, &rs->ctr_flags)) {
1396 				rs->ti->error = "Only one min_recovery_rate argument pair allowed";
1397 				return -EINVAL;
1398 			}
1399 			if (value > INT_MAX) {
1400 				rs->ti->error = "min_recovery_rate out of range";
1401 				return -EINVAL;
1402 			}
1403 			rs->md.sync_speed_min = (int)value;
1404 		} else if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_MAX_RECOVERY_RATE))) {
1405 			if (test_and_set_bit(__CTR_FLAG_MAX_RECOVERY_RATE, &rs->ctr_flags)) {
1406 				rs->ti->error = "Only one max_recovery_rate argument pair allowed";
1407 				return -EINVAL;
1408 			}
1409 			if (value > INT_MAX) {
1410 				rs->ti->error = "max_recovery_rate out of range";
1411 				return -EINVAL;
1412 			}
1413 			rs->md.sync_speed_max = (int)value;
1414 		} else if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_REGION_SIZE))) {
1415 			if (test_and_set_bit(__CTR_FLAG_REGION_SIZE, &rs->ctr_flags)) {
1416 				rs->ti->error = "Only one region_size argument pair allowed";
1417 				return -EINVAL;
1418 			}
1419 
1420 			region_size = value;
1421 			rs->requested_bitmap_chunk_sectors = value;
1422 		} else if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_RAID10_COPIES))) {
1423 			if (test_and_set_bit(__CTR_FLAG_RAID10_COPIES, &rs->ctr_flags)) {
1424 				rs->ti->error = "Only one raid10_copies argument pair allowed";
1425 				return -EINVAL;
1426 			}
1427 
1428 			if (!__within_range(value, 2, rs->md.raid_disks)) {
1429 				rs->ti->error = "Bad value for 'raid10_copies'";
1430 				return -EINVAL;
1431 			}
1432 
1433 			raid10_copies = value;
1434 		} else {
1435 			DMERR("Unable to parse RAID parameter: %s", key);
1436 			rs->ti->error = "Unable to parse RAID parameter";
1437 			return -EINVAL;
1438 		}
1439 	}
1440 
1441 	if (test_bit(__CTR_FLAG_SYNC, &rs->ctr_flags) &&
1442 	    test_bit(__CTR_FLAG_NOSYNC, &rs->ctr_flags)) {
1443 		rs->ti->error = "sync and nosync are mutually exclusive";
1444 		return -EINVAL;
1445 	}
1446 
1447 	if (test_bit(__CTR_FLAG_REBUILD, &rs->ctr_flags) &&
1448 	    (test_bit(__CTR_FLAG_SYNC, &rs->ctr_flags) ||
1449 	     test_bit(__CTR_FLAG_NOSYNC, &rs->ctr_flags))) {
1450 		rs->ti->error = "sync/nosync and rebuild are mutually exclusive";
1451 		return -EINVAL;
1452 	}
1453 
1454 	if (write_mostly >= rs->md.raid_disks) {
1455 		rs->ti->error = "Can't set all raid1 devices to write_mostly";
1456 		return -EINVAL;
1457 	}
1458 
1459 	if (validate_region_size(rs, region_size))
1460 		return -EINVAL;
1461 
1462 	if (rs->md.chunk_sectors)
1463 		max_io_len = rs->md.chunk_sectors;
1464 	else
1465 		max_io_len = region_size;
1466 
1467 	if (dm_set_target_max_io_len(rs->ti, max_io_len))
1468 		return -EINVAL;
1469 
1470 	if (rt_is_raid10(rt)) {
1471 		if (raid10_copies > rs->md.raid_disks) {
1472 			rs->ti->error = "Not enough devices to satisfy specification";
1473 			return -EINVAL;
1474 		}
1475 
1476 		rs->md.new_layout = raid10_format_to_md_layout(rs, raid10_format, raid10_copies);
1477 		if (rs->md.new_layout < 0) {
1478 			rs->ti->error = "Error getting raid10 format";
1479 			return rs->md.new_layout;
1480 		}
1481 
1482 		rt = get_raid_type_by_ll(10, rs->md.new_layout);
1483 		if (!rt) {
1484 			rs->ti->error = "Failed to recognize new raid10 layout";
1485 			return -EINVAL;
1486 		}
1487 
1488 		if ((rt->algorithm == ALGORITHM_RAID10_DEFAULT ||
1489 		     rt->algorithm == ALGORITHM_RAID10_NEAR) &&
1490 		    test_bit(__CTR_FLAG_RAID10_USE_NEAR_SETS, &rs->ctr_flags)) {
1491 			rs->ti->error = "RAID10 format 'near' and 'raid10_use_near_sets' are incompatible";
1492 			return -EINVAL;
1493 		}
1494 	}
1495 
1496 	rs->raid10_copies = raid10_copies;
1497 
1498 	/* Assume there are no metadata devices until the drives are parsed */
1499 	rs->md.persistent = 0;
1500 	rs->md.external = 1;
1501 
1502 	/* Check, if any invalid ctr arguments have been passed in for the raid level */
1503 	return rs_check_for_valid_flags(rs);
1504 }
1505 
1506 /* Set raid4/5/6 cache size */
1507 static int rs_set_raid456_stripe_cache(struct raid_set *rs)
1508 {
1509 	int r;
1510 	struct r5conf *conf;
1511 	struct mddev *mddev = &rs->md;
1512 	uint32_t min_stripes = max(mddev->chunk_sectors, mddev->new_chunk_sectors) / 2;
1513 	uint32_t nr_stripes = rs->stripe_cache_entries;
1514 
1515 	if (!rt_is_raid456(rs->raid_type)) {
1516 		rs->ti->error = "Inappropriate raid level; cannot change stripe_cache size";
1517 		return -EINVAL;
1518 	}
1519 
1520 	if (nr_stripes < min_stripes) {
1521 		DMINFO("Adjusting requested %u stripe cache entries to %u to suit stripe size",
1522 		       nr_stripes, min_stripes);
1523 		nr_stripes = min_stripes;
1524 	}
1525 
1526 	conf = mddev->private;
1527 	if (!conf) {
1528 		rs->ti->error = "Cannot change stripe_cache size on inactive RAID set";
1529 		return -EINVAL;
1530 	}
1531 
1532 	/* Try setting number of stripes in raid456 stripe cache */
1533 	if (conf->min_nr_stripes != nr_stripes) {
1534 		r = raid5_set_cache_size(mddev, nr_stripes);
1535 		if (r) {
1536 			rs->ti->error = "Failed to set raid4/5/6 stripe cache size";
1537 			return r;
1538 		}
1539 
1540 		DMINFO("%u stripe cache entries", nr_stripes);
1541 	}
1542 
1543 	return 0;
1544 }
1545 
1546 /* Return # of data stripes as kept in mddev as of @rs (i.e. as of superblock) */
1547 static unsigned int mddev_data_stripes(struct raid_set *rs)
1548 {
1549 	return rs->md.raid_disks - rs->raid_type->parity_devs;
1550 }
1551 
1552 /* Return # of data stripes of @rs (i.e. as of ctr) */
1553 static unsigned int rs_data_stripes(struct raid_set *rs)
1554 {
1555 	return rs->raid_disks - rs->raid_type->parity_devs;
1556 }
1557 
1558 /*
1559  * Retrieve rdev->sectors from any valid raid device of @rs
1560  * to allow userpace to pass in arbitray "- -" device tupples.
1561  */
1562 static sector_t __rdev_sectors(struct raid_set *rs)
1563 {
1564 	int i;
1565 
1566 	for (i = 0; i < rs->md.raid_disks; i++) {
1567 		struct md_rdev *rdev = &rs->dev[i].rdev;
1568 
1569 		if (!test_bit(Journal, &rdev->flags) &&
1570 		    rdev->bdev && rdev->sectors)
1571 			return rdev->sectors;
1572 	}
1573 
1574 	return 0;
1575 }
1576 
1577 /* Calculate the sectors per device and per array used for @rs */
1578 static int rs_set_dev_and_array_sectors(struct raid_set *rs, bool use_mddev)
1579 {
1580 	int delta_disks;
1581 	unsigned int data_stripes;
1582 	struct mddev *mddev = &rs->md;
1583 	struct md_rdev *rdev;
1584 	sector_t array_sectors = rs->ti->len, dev_sectors = rs->ti->len;
1585 
1586 	if (use_mddev) {
1587 		delta_disks = mddev->delta_disks;
1588 		data_stripes = mddev_data_stripes(rs);
1589 	} else {
1590 		delta_disks = rs->delta_disks;
1591 		data_stripes = rs_data_stripes(rs);
1592 	}
1593 
1594 	/* Special raid1 case w/o delta_disks support (yet) */
1595 	if (rt_is_raid1(rs->raid_type))
1596 		;
1597 	else if (rt_is_raid10(rs->raid_type)) {
1598 		if (rs->raid10_copies < 2 ||
1599 		    delta_disks < 0) {
1600 			rs->ti->error = "Bogus raid10 data copies or delta disks";
1601 			return -EINVAL;
1602 		}
1603 
1604 		dev_sectors *= rs->raid10_copies;
1605 		if (sector_div(dev_sectors, data_stripes))
1606 			goto bad;
1607 
1608 		array_sectors = (data_stripes + delta_disks) * dev_sectors;
1609 		if (sector_div(array_sectors, rs->raid10_copies))
1610 			goto bad;
1611 
1612 	} else if (sector_div(dev_sectors, data_stripes))
1613 		goto bad;
1614 
1615 	else
1616 		/* Striped layouts */
1617 		array_sectors = (data_stripes + delta_disks) * dev_sectors;
1618 
1619 	rdev_for_each(rdev, mddev)
1620 		if (!test_bit(Journal, &rdev->flags))
1621 			rdev->sectors = dev_sectors;
1622 
1623 	mddev->array_sectors = array_sectors;
1624 	mddev->dev_sectors = dev_sectors;
1625 
1626 	return 0;
1627 bad:
1628 	rs->ti->error = "Target length not divisible by number of data devices";
1629 	return -EINVAL;
1630 }
1631 
1632 /* Setup recovery on @rs */
1633 static void __rs_setup_recovery(struct raid_set *rs, sector_t dev_sectors)
1634 {
1635 	/* raid0 does not recover */
1636 	if (rs_is_raid0(rs))
1637 		rs->md.recovery_cp = MaxSector;
1638 	/*
1639 	 * A raid6 set has to be recovered either
1640 	 * completely or for the grown part to
1641 	 * ensure proper parity and Q-Syndrome
1642 	 */
1643 	else if (rs_is_raid6(rs))
1644 		rs->md.recovery_cp = dev_sectors;
1645 	/*
1646 	 * Other raid set types may skip recovery
1647 	 * depending on the 'nosync' flag.
1648 	 */
1649 	else
1650 		rs->md.recovery_cp = test_bit(__CTR_FLAG_NOSYNC, &rs->ctr_flags)
1651 				     ? MaxSector : dev_sectors;
1652 }
1653 
1654 /* Setup recovery on @rs based on raid type, device size and 'nosync' flag */
1655 static void rs_setup_recovery(struct raid_set *rs, sector_t dev_sectors)
1656 {
1657 	if (!dev_sectors)
1658 		/* New raid set or 'sync' flag provided */
1659 		__rs_setup_recovery(rs, 0);
1660 	else if (dev_sectors == MaxSector)
1661 		/* Prevent recovery */
1662 		__rs_setup_recovery(rs, MaxSector);
1663 	else if (__rdev_sectors(rs) < dev_sectors)
1664 		/* Grown raid set */
1665 		__rs_setup_recovery(rs, __rdev_sectors(rs));
1666 	else
1667 		__rs_setup_recovery(rs, MaxSector);
1668 }
1669 
1670 static void do_table_event(struct work_struct *ws)
1671 {
1672 	struct raid_set *rs = container_of(ws, struct raid_set, md.event_work);
1673 
1674 	smp_rmb(); /* Make sure we access most actual mddev properties */
1675 	if (!rs_is_reshaping(rs))
1676 		rs_set_capacity(rs);
1677 	dm_table_event(rs->ti->table);
1678 }
1679 
1680 static int raid_is_congested(struct dm_target_callbacks *cb, int bits)
1681 {
1682 	struct raid_set *rs = container_of(cb, struct raid_set, callbacks);
1683 
1684 	return mddev_congested(&rs->md, bits);
1685 }
1686 
1687 /*
1688  * Make sure a valid takover (level switch) is being requested on @rs
1689  *
1690  * Conversions of raid sets from one MD personality to another
1691  * have to conform to restrictions which are enforced here.
1692  */
1693 static int rs_check_takeover(struct raid_set *rs)
1694 {
1695 	struct mddev *mddev = &rs->md;
1696 	unsigned int near_copies;
1697 
1698 	if (rs->md.degraded) {
1699 		rs->ti->error = "Can't takeover degraded raid set";
1700 		return -EPERM;
1701 	}
1702 
1703 	if (rs_is_reshaping(rs)) {
1704 		rs->ti->error = "Can't takeover reshaping raid set";
1705 		return -EPERM;
1706 	}
1707 
1708 	switch (mddev->level) {
1709 	case 0:
1710 		/* raid0 -> raid1/5 with one disk */
1711 		if ((mddev->new_level == 1 || mddev->new_level == 5) &&
1712 		    mddev->raid_disks == 1)
1713 			return 0;
1714 
1715 		/* raid0 -> raid10 */
1716 		if (mddev->new_level == 10 &&
1717 		    !(rs->raid_disks % mddev->raid_disks))
1718 			return 0;
1719 
1720 		/* raid0 with multiple disks -> raid4/5/6 */
1721 		if (__within_range(mddev->new_level, 4, 6) &&
1722 		    mddev->new_layout == ALGORITHM_PARITY_N &&
1723 		    mddev->raid_disks > 1)
1724 			return 0;
1725 
1726 		break;
1727 
1728 	case 10:
1729 		/* Can't takeover raid10_offset! */
1730 		if (__is_raid10_offset(mddev->layout))
1731 			break;
1732 
1733 		near_copies = __raid10_near_copies(mddev->layout);
1734 
1735 		/* raid10* -> raid0 */
1736 		if (mddev->new_level == 0) {
1737 			/* Can takeover raid10_near with raid disks divisable by data copies! */
1738 			if (near_copies > 1 &&
1739 			    !(mddev->raid_disks % near_copies)) {
1740 				mddev->raid_disks /= near_copies;
1741 				mddev->delta_disks = mddev->raid_disks;
1742 				return 0;
1743 			}
1744 
1745 			/* Can takeover raid10_far */
1746 			if (near_copies == 1 &&
1747 			    __raid10_far_copies(mddev->layout) > 1)
1748 				return 0;
1749 
1750 			break;
1751 		}
1752 
1753 		/* raid10_{near,far} -> raid1 */
1754 		if (mddev->new_level == 1 &&
1755 		    max(near_copies, __raid10_far_copies(mddev->layout)) == mddev->raid_disks)
1756 			return 0;
1757 
1758 		/* raid10_{near,far} with 2 disks -> raid4/5 */
1759 		if (__within_range(mddev->new_level, 4, 5) &&
1760 		    mddev->raid_disks == 2)
1761 			return 0;
1762 		break;
1763 
1764 	case 1:
1765 		/* raid1 with 2 disks -> raid4/5 */
1766 		if (__within_range(mddev->new_level, 4, 5) &&
1767 		    mddev->raid_disks == 2) {
1768 			mddev->degraded = 1;
1769 			return 0;
1770 		}
1771 
1772 		/* raid1 -> raid0 */
1773 		if (mddev->new_level == 0 &&
1774 		    mddev->raid_disks == 1)
1775 			return 0;
1776 
1777 		/* raid1 -> raid10 */
1778 		if (mddev->new_level == 10)
1779 			return 0;
1780 		break;
1781 
1782 	case 4:
1783 		/* raid4 -> raid0 */
1784 		if (mddev->new_level == 0)
1785 			return 0;
1786 
1787 		/* raid4 -> raid1/5 with 2 disks */
1788 		if ((mddev->new_level == 1 || mddev->new_level == 5) &&
1789 		    mddev->raid_disks == 2)
1790 			return 0;
1791 
1792 		/* raid4 -> raid5/6 with parity N */
1793 		if (__within_range(mddev->new_level, 5, 6) &&
1794 		    mddev->layout == ALGORITHM_PARITY_N)
1795 			return 0;
1796 		break;
1797 
1798 	case 5:
1799 		/* raid5 with parity N -> raid0 */
1800 		if (mddev->new_level == 0 &&
1801 		    mddev->layout == ALGORITHM_PARITY_N)
1802 			return 0;
1803 
1804 		/* raid5 with parity N -> raid4 */
1805 		if (mddev->new_level == 4 &&
1806 		    mddev->layout == ALGORITHM_PARITY_N)
1807 			return 0;
1808 
1809 		/* raid5 with 2 disks -> raid1/4/10 */
1810 		if ((mddev->new_level == 1 || mddev->new_level == 4 || mddev->new_level == 10) &&
1811 		    mddev->raid_disks == 2)
1812 			return 0;
1813 
1814 		/* raid5_* ->  raid6_*_6 with Q-Syndrome N (e.g. raid5_ra -> raid6_ra_6 */
1815 		if (mddev->new_level == 6 &&
1816 		    ((mddev->layout == ALGORITHM_PARITY_N && mddev->new_layout == ALGORITHM_PARITY_N) ||
1817 		      __within_range(mddev->new_layout, ALGORITHM_LEFT_ASYMMETRIC_6, ALGORITHM_RIGHT_SYMMETRIC_6)))
1818 			return 0;
1819 		break;
1820 
1821 	case 6:
1822 		/* raid6 with parity N -> raid0 */
1823 		if (mddev->new_level == 0 &&
1824 		    mddev->layout == ALGORITHM_PARITY_N)
1825 			return 0;
1826 
1827 		/* raid6 with parity N -> raid4 */
1828 		if (mddev->new_level == 4 &&
1829 		    mddev->layout == ALGORITHM_PARITY_N)
1830 			return 0;
1831 
1832 		/* raid6_*_n with Q-Syndrome N -> raid5_* */
1833 		if (mddev->new_level == 5 &&
1834 		    ((mddev->layout == ALGORITHM_PARITY_N && mddev->new_layout == ALGORITHM_PARITY_N) ||
1835 		     __within_range(mddev->new_layout, ALGORITHM_LEFT_ASYMMETRIC, ALGORITHM_RIGHT_SYMMETRIC)))
1836 			return 0;
1837 
1838 	default:
1839 		break;
1840 	}
1841 
1842 	rs->ti->error = "takeover not possible";
1843 	return -EINVAL;
1844 }
1845 
1846 /* True if @rs requested to be taken over */
1847 static bool rs_takeover_requested(struct raid_set *rs)
1848 {
1849 	return rs->md.new_level != rs->md.level;
1850 }
1851 
1852 /* True if @rs is requested to reshape by ctr */
1853 static bool rs_reshape_requested(struct raid_set *rs)
1854 {
1855 	bool change;
1856 	struct mddev *mddev = &rs->md;
1857 
1858 	if (rs_takeover_requested(rs))
1859 		return false;
1860 
1861 	if (!mddev->level)
1862 		return false;
1863 
1864 	change = mddev->new_layout != mddev->layout ||
1865 		 mddev->new_chunk_sectors != mddev->chunk_sectors ||
1866 		 rs->delta_disks;
1867 
1868 	/* Historical case to support raid1 reshape without delta disks */
1869 	if (mddev->level == 1) {
1870 		if (rs->delta_disks)
1871 			return !!rs->delta_disks;
1872 
1873 		return !change &&
1874 		       mddev->raid_disks != rs->raid_disks;
1875 	}
1876 
1877 	if (mddev->level == 10)
1878 		return change &&
1879 		       !__is_raid10_far(mddev->new_layout) &&
1880 		       rs->delta_disks >= 0;
1881 
1882 	return change;
1883 }
1884 
1885 /*  Features */
1886 #define	FEATURE_FLAG_SUPPORTS_V190	0x1 /* Supports extended superblock */
1887 
1888 /* State flags for sb->flags */
1889 #define	SB_FLAG_RESHAPE_ACTIVE		0x1
1890 #define	SB_FLAG_RESHAPE_BACKWARDS	0x2
1891 
1892 /*
1893  * This structure is never routinely used by userspace, unlike md superblocks.
1894  * Devices with this superblock should only ever be accessed via device-mapper.
1895  */
1896 #define DM_RAID_MAGIC 0x64526D44
1897 struct dm_raid_superblock {
1898 	__le32 magic;		/* "DmRd" */
1899 	__le32 compat_features;	/* Used to indicate compatible features (like 1.9.0 ondisk metadata extension) */
1900 
1901 	__le32 num_devices;	/* Number of devices in this raid set. (Max 64) */
1902 	__le32 array_position;	/* The position of this drive in the raid set */
1903 
1904 	__le64 events;		/* Incremented by md when superblock updated */
1905 	__le64 failed_devices;	/* Pre 1.9.0 part of bit field of devices to */
1906 				/* indicate failures (see extension below) */
1907 
1908 	/*
1909 	 * This offset tracks the progress of the repair or replacement of
1910 	 * an individual drive.
1911 	 */
1912 	__le64 disk_recovery_offset;
1913 
1914 	/*
1915 	 * This offset tracks the progress of the initial raid set
1916 	 * synchronisation/parity calculation.
1917 	 */
1918 	__le64 array_resync_offset;
1919 
1920 	/*
1921 	 * raid characteristics
1922 	 */
1923 	__le32 level;
1924 	__le32 layout;
1925 	__le32 stripe_sectors;
1926 
1927 	/********************************************************************
1928 	 * BELOW FOLLOW V1.9.0 EXTENSIONS TO THE PRISTINE SUPERBLOCK FORMAT!!!
1929 	 *
1930 	 * FEATURE_FLAG_SUPPORTS_V190 in the compat_features member indicates that those exist
1931 	 */
1932 
1933 	__le32 flags; /* Flags defining array states for reshaping */
1934 
1935 	/*
1936 	 * This offset tracks the progress of a raid
1937 	 * set reshape in order to be able to restart it
1938 	 */
1939 	__le64 reshape_position;
1940 
1941 	/*
1942 	 * These define the properties of the array in case of an interrupted reshape
1943 	 */
1944 	__le32 new_level;
1945 	__le32 new_layout;
1946 	__le32 new_stripe_sectors;
1947 	__le32 delta_disks;
1948 
1949 	__le64 array_sectors; /* Array size in sectors */
1950 
1951 	/*
1952 	 * Sector offsets to data on devices (reshaping).
1953 	 * Needed to support out of place reshaping, thus
1954 	 * not writing over any stripes whilst converting
1955 	 * them from old to new layout
1956 	 */
1957 	__le64 data_offset;
1958 	__le64 new_data_offset;
1959 
1960 	__le64 sectors; /* Used device size in sectors */
1961 
1962 	/*
1963 	 * Additonal Bit field of devices indicating failures to support
1964 	 * up to 256 devices with the 1.9.0 on-disk metadata format
1965 	 */
1966 	__le64 extended_failed_devices[DISKS_ARRAY_ELEMS - 1];
1967 
1968 	__le32 incompat_features;	/* Used to indicate any incompatible features */
1969 
1970 	/* Always set rest up to logical block size to 0 when writing (see get_metadata_device() below). */
1971 } __packed;
1972 
1973 /*
1974  * Check for reshape constraints on raid set @rs:
1975  *
1976  * - reshape function non-existent
1977  * - degraded set
1978  * - ongoing recovery
1979  * - ongoing reshape
1980  *
1981  * Returns 0 if none or -EPERM if given constraint
1982  * and error message reference in @errmsg
1983  */
1984 static int rs_check_reshape(struct raid_set *rs)
1985 {
1986 	struct mddev *mddev = &rs->md;
1987 
1988 	if (!mddev->pers || !mddev->pers->check_reshape)
1989 		rs->ti->error = "Reshape not supported";
1990 	else if (mddev->degraded)
1991 		rs->ti->error = "Can't reshape degraded raid set";
1992 	else if (rs_is_recovering(rs))
1993 		rs->ti->error = "Convert request on recovering raid set prohibited";
1994 	else if (rs_is_reshaping(rs))
1995 		rs->ti->error = "raid set already reshaping!";
1996 	else if (!(rs_is_raid1(rs) || rs_is_raid10(rs) || rs_is_raid456(rs)))
1997 		rs->ti->error = "Reshaping only supported for raid1/4/5/6/10";
1998 	else
1999 		return 0;
2000 
2001 	return -EPERM;
2002 }
2003 
2004 static int read_disk_sb(struct md_rdev *rdev, int size, bool force_reload)
2005 {
2006 	BUG_ON(!rdev->sb_page);
2007 
2008 	if (rdev->sb_loaded && !force_reload)
2009 		return 0;
2010 
2011 	rdev->sb_loaded = 0;
2012 
2013 	if (!sync_page_io(rdev, 0, size, rdev->sb_page, REQ_OP_READ, 0, true)) {
2014 		DMERR("Failed to read superblock of device at position %d",
2015 		      rdev->raid_disk);
2016 		md_error(rdev->mddev, rdev);
2017 		set_bit(Faulty, &rdev->flags);
2018 		return -EIO;
2019 	}
2020 
2021 	rdev->sb_loaded = 1;
2022 
2023 	return 0;
2024 }
2025 
2026 static void sb_retrieve_failed_devices(struct dm_raid_superblock *sb, uint64_t *failed_devices)
2027 {
2028 	failed_devices[0] = le64_to_cpu(sb->failed_devices);
2029 	memset(failed_devices + 1, 0, sizeof(sb->extended_failed_devices));
2030 
2031 	if (le32_to_cpu(sb->compat_features) & FEATURE_FLAG_SUPPORTS_V190) {
2032 		int i = ARRAY_SIZE(sb->extended_failed_devices);
2033 
2034 		while (i--)
2035 			failed_devices[i+1] = le64_to_cpu(sb->extended_failed_devices[i]);
2036 	}
2037 }
2038 
2039 static void sb_update_failed_devices(struct dm_raid_superblock *sb, uint64_t *failed_devices)
2040 {
2041 	int i = ARRAY_SIZE(sb->extended_failed_devices);
2042 
2043 	sb->failed_devices = cpu_to_le64(failed_devices[0]);
2044 	while (i--)
2045 		sb->extended_failed_devices[i] = cpu_to_le64(failed_devices[i+1]);
2046 }
2047 
2048 /*
2049  * Synchronize the superblock members with the raid set properties
2050  *
2051  * All superblock data is little endian.
2052  */
2053 static void super_sync(struct mddev *mddev, struct md_rdev *rdev)
2054 {
2055 	bool update_failed_devices = false;
2056 	unsigned int i;
2057 	uint64_t failed_devices[DISKS_ARRAY_ELEMS];
2058 	struct dm_raid_superblock *sb;
2059 	struct raid_set *rs = container_of(mddev, struct raid_set, md);
2060 
2061 	/* No metadata device, no superblock */
2062 	if (!rdev->meta_bdev)
2063 		return;
2064 
2065 	BUG_ON(!rdev->sb_page);
2066 
2067 	sb = page_address(rdev->sb_page);
2068 
2069 	sb_retrieve_failed_devices(sb, failed_devices);
2070 
2071 	for (i = 0; i < rs->raid_disks; i++)
2072 		if (!rs->dev[i].data_dev || test_bit(Faulty, &rs->dev[i].rdev.flags)) {
2073 			update_failed_devices = true;
2074 			set_bit(i, (void *) failed_devices);
2075 		}
2076 
2077 	if (update_failed_devices)
2078 		sb_update_failed_devices(sb, failed_devices);
2079 
2080 	sb->magic = cpu_to_le32(DM_RAID_MAGIC);
2081 	sb->compat_features = cpu_to_le32(FEATURE_FLAG_SUPPORTS_V190);
2082 
2083 	sb->num_devices = cpu_to_le32(mddev->raid_disks);
2084 	sb->array_position = cpu_to_le32(rdev->raid_disk);
2085 
2086 	sb->events = cpu_to_le64(mddev->events);
2087 
2088 	sb->disk_recovery_offset = cpu_to_le64(rdev->recovery_offset);
2089 	sb->array_resync_offset = cpu_to_le64(mddev->recovery_cp);
2090 
2091 	sb->level = cpu_to_le32(mddev->level);
2092 	sb->layout = cpu_to_le32(mddev->layout);
2093 	sb->stripe_sectors = cpu_to_le32(mddev->chunk_sectors);
2094 
2095 	/********************************************************************
2096 	 * BELOW FOLLOW V1.9.0 EXTENSIONS TO THE PRISTINE SUPERBLOCK FORMAT!!!
2097 	 *
2098 	 * FEATURE_FLAG_SUPPORTS_V190 in the compat_features member indicates that those exist
2099 	 */
2100 	sb->new_level = cpu_to_le32(mddev->new_level);
2101 	sb->new_layout = cpu_to_le32(mddev->new_layout);
2102 	sb->new_stripe_sectors = cpu_to_le32(mddev->new_chunk_sectors);
2103 
2104 	sb->delta_disks = cpu_to_le32(mddev->delta_disks);
2105 
2106 	smp_rmb(); /* Make sure we access most recent reshape position */
2107 	sb->reshape_position = cpu_to_le64(mddev->reshape_position);
2108 	if (le64_to_cpu(sb->reshape_position) != MaxSector) {
2109 		/* Flag ongoing reshape */
2110 		sb->flags |= cpu_to_le32(SB_FLAG_RESHAPE_ACTIVE);
2111 
2112 		if (mddev->delta_disks < 0 || mddev->reshape_backwards)
2113 			sb->flags |= cpu_to_le32(SB_FLAG_RESHAPE_BACKWARDS);
2114 	} else {
2115 		/* Clear reshape flags */
2116 		sb->flags &= ~(cpu_to_le32(SB_FLAG_RESHAPE_ACTIVE|SB_FLAG_RESHAPE_BACKWARDS));
2117 	}
2118 
2119 	sb->array_sectors = cpu_to_le64(mddev->array_sectors);
2120 	sb->data_offset = cpu_to_le64(rdev->data_offset);
2121 	sb->new_data_offset = cpu_to_le64(rdev->new_data_offset);
2122 	sb->sectors = cpu_to_le64(rdev->sectors);
2123 	sb->incompat_features = cpu_to_le32(0);
2124 
2125 	/* Zero out the rest of the payload after the size of the superblock */
2126 	memset(sb + 1, 0, rdev->sb_size - sizeof(*sb));
2127 }
2128 
2129 /*
2130  * super_load
2131  *
2132  * This function creates a superblock if one is not found on the device
2133  * and will decide which superblock to use if there's a choice.
2134  *
2135  * Return: 1 if use rdev, 0 if use refdev, -Exxx otherwise
2136  */
2137 static int super_load(struct md_rdev *rdev, struct md_rdev *refdev)
2138 {
2139 	int r;
2140 	struct dm_raid_superblock *sb;
2141 	struct dm_raid_superblock *refsb;
2142 	uint64_t events_sb, events_refsb;
2143 
2144 	rdev->sb_start = 0;
2145 	rdev->sb_size = bdev_logical_block_size(rdev->meta_bdev);
2146 	if (rdev->sb_size < sizeof(*sb) || rdev->sb_size > PAGE_SIZE) {
2147 		DMERR("superblock size of a logical block is no longer valid");
2148 		return -EINVAL;
2149 	}
2150 
2151 	r = read_disk_sb(rdev, rdev->sb_size, false);
2152 	if (r)
2153 		return r;
2154 
2155 	sb = page_address(rdev->sb_page);
2156 
2157 	/*
2158 	 * Two cases that we want to write new superblocks and rebuild:
2159 	 * 1) New device (no matching magic number)
2160 	 * 2) Device specified for rebuild (!In_sync w/ offset == 0)
2161 	 */
2162 	if ((sb->magic != cpu_to_le32(DM_RAID_MAGIC)) ||
2163 	    (!test_bit(In_sync, &rdev->flags) && !rdev->recovery_offset)) {
2164 		super_sync(rdev->mddev, rdev);
2165 
2166 		set_bit(FirstUse, &rdev->flags);
2167 		sb->compat_features = cpu_to_le32(FEATURE_FLAG_SUPPORTS_V190);
2168 
2169 		/* Force writing of superblocks to disk */
2170 		set_bit(MD_SB_CHANGE_DEVS, &rdev->mddev->sb_flags);
2171 
2172 		/* Any superblock is better than none, choose that if given */
2173 		return refdev ? 0 : 1;
2174 	}
2175 
2176 	if (!refdev)
2177 		return 1;
2178 
2179 	events_sb = le64_to_cpu(sb->events);
2180 
2181 	refsb = page_address(refdev->sb_page);
2182 	events_refsb = le64_to_cpu(refsb->events);
2183 
2184 	return (events_sb > events_refsb) ? 1 : 0;
2185 }
2186 
2187 static int super_init_validation(struct raid_set *rs, struct md_rdev *rdev)
2188 {
2189 	int role;
2190 	unsigned int d;
2191 	struct mddev *mddev = &rs->md;
2192 	uint64_t events_sb;
2193 	uint64_t failed_devices[DISKS_ARRAY_ELEMS];
2194 	struct dm_raid_superblock *sb;
2195 	uint32_t new_devs = 0, rebuild_and_new = 0, rebuilds = 0;
2196 	struct md_rdev *r;
2197 	struct dm_raid_superblock *sb2;
2198 
2199 	sb = page_address(rdev->sb_page);
2200 	events_sb = le64_to_cpu(sb->events);
2201 
2202 	/*
2203 	 * Initialise to 1 if this is a new superblock.
2204 	 */
2205 	mddev->events = events_sb ? : 1;
2206 
2207 	mddev->reshape_position = MaxSector;
2208 
2209 	mddev->raid_disks = le32_to_cpu(sb->num_devices);
2210 	mddev->level = le32_to_cpu(sb->level);
2211 	mddev->layout = le32_to_cpu(sb->layout);
2212 	mddev->chunk_sectors = le32_to_cpu(sb->stripe_sectors);
2213 
2214 	/*
2215 	 * Reshaping is supported, e.g. reshape_position is valid
2216 	 * in superblock and superblock content is authoritative.
2217 	 */
2218 	if (le32_to_cpu(sb->compat_features) & FEATURE_FLAG_SUPPORTS_V190) {
2219 		/* Superblock is authoritative wrt given raid set layout! */
2220 		mddev->new_level = le32_to_cpu(sb->new_level);
2221 		mddev->new_layout = le32_to_cpu(sb->new_layout);
2222 		mddev->new_chunk_sectors = le32_to_cpu(sb->new_stripe_sectors);
2223 		mddev->delta_disks = le32_to_cpu(sb->delta_disks);
2224 		mddev->array_sectors = le64_to_cpu(sb->array_sectors);
2225 
2226 		/* raid was reshaping and got interrupted */
2227 		if (le32_to_cpu(sb->flags) & SB_FLAG_RESHAPE_ACTIVE) {
2228 			if (test_bit(__CTR_FLAG_DELTA_DISKS, &rs->ctr_flags)) {
2229 				DMERR("Reshape requested but raid set is still reshaping");
2230 				return -EINVAL;
2231 			}
2232 
2233 			if (mddev->delta_disks < 0 ||
2234 			    (!mddev->delta_disks && (le32_to_cpu(sb->flags) & SB_FLAG_RESHAPE_BACKWARDS)))
2235 				mddev->reshape_backwards = 1;
2236 			else
2237 				mddev->reshape_backwards = 0;
2238 
2239 			mddev->reshape_position = le64_to_cpu(sb->reshape_position);
2240 			rs->raid_type = get_raid_type_by_ll(mddev->level, mddev->layout);
2241 		}
2242 
2243 	} else {
2244 		/*
2245 		 * No takeover/reshaping, because we don't have the extended v1.9.0 metadata
2246 		 */
2247 		struct raid_type *rt_cur = get_raid_type_by_ll(mddev->level, mddev->layout);
2248 		struct raid_type *rt_new = get_raid_type_by_ll(mddev->new_level, mddev->new_layout);
2249 
2250 		if (rs_takeover_requested(rs)) {
2251 			if (rt_cur && rt_new)
2252 				DMERR("Takeover raid sets from %s to %s not yet supported by metadata. (raid level change)",
2253 				      rt_cur->name, rt_new->name);
2254 			else
2255 				DMERR("Takeover raid sets not yet supported by metadata. (raid level change)");
2256 			return -EINVAL;
2257 		} else if (rs_reshape_requested(rs)) {
2258 			DMERR("Reshaping raid sets not yet supported by metadata. (raid layout change keeping level)");
2259 			if (mddev->layout != mddev->new_layout) {
2260 				if (rt_cur && rt_new)
2261 					DMERR("	 current layout %s vs new layout %s",
2262 					      rt_cur->name, rt_new->name);
2263 				else
2264 					DMERR("	 current layout 0x%X vs new layout 0x%X",
2265 					      le32_to_cpu(sb->layout), mddev->new_layout);
2266 			}
2267 			if (mddev->chunk_sectors != mddev->new_chunk_sectors)
2268 				DMERR("	 current stripe sectors %u vs new stripe sectors %u",
2269 				      mddev->chunk_sectors, mddev->new_chunk_sectors);
2270 			if (rs->delta_disks)
2271 				DMERR("	 current %u disks vs new %u disks",
2272 				      mddev->raid_disks, mddev->raid_disks + rs->delta_disks);
2273 			if (rs_is_raid10(rs)) {
2274 				DMERR("	 Old layout: %s w/ %u copies",
2275 				      raid10_md_layout_to_format(mddev->layout),
2276 				      raid10_md_layout_to_copies(mddev->layout));
2277 				DMERR("	 New layout: %s w/ %u copies",
2278 				      raid10_md_layout_to_format(mddev->new_layout),
2279 				      raid10_md_layout_to_copies(mddev->new_layout));
2280 			}
2281 			return -EINVAL;
2282 		}
2283 
2284 		DMINFO("Discovered old metadata format; upgrading to extended metadata format");
2285 	}
2286 
2287 	if (!test_bit(__CTR_FLAG_NOSYNC, &rs->ctr_flags))
2288 		mddev->recovery_cp = le64_to_cpu(sb->array_resync_offset);
2289 
2290 	/*
2291 	 * During load, we set FirstUse if a new superblock was written.
2292 	 * There are two reasons we might not have a superblock:
2293 	 * 1) The raid set is brand new - in which case, all of the
2294 	 *    devices must have their In_sync bit set.	Also,
2295 	 *    recovery_cp must be 0, unless forced.
2296 	 * 2) This is a new device being added to an old raid set
2297 	 *    and the new device needs to be rebuilt - in which
2298 	 *    case the In_sync bit will /not/ be set and
2299 	 *    recovery_cp must be MaxSector.
2300 	 * 3) This is/are a new device(s) being added to an old
2301 	 *    raid set during takeover to a higher raid level
2302 	 *    to provide capacity for redundancy or during reshape
2303 	 *    to add capacity to grow the raid set.
2304 	 */
2305 	d = 0;
2306 	rdev_for_each(r, mddev) {
2307 		if (test_bit(Journal, &rdev->flags))
2308 			continue;
2309 
2310 		if (test_bit(FirstUse, &r->flags))
2311 			new_devs++;
2312 
2313 		if (!test_bit(In_sync, &r->flags)) {
2314 			DMINFO("Device %d specified for rebuild; clearing superblock",
2315 				r->raid_disk);
2316 			rebuilds++;
2317 
2318 			if (test_bit(FirstUse, &r->flags))
2319 				rebuild_and_new++;
2320 		}
2321 
2322 		d++;
2323 	}
2324 
2325 	if (new_devs == rs->raid_disks || !rebuilds) {
2326 		/* Replace a broken device */
2327 		if (new_devs == 1 && !rs->delta_disks)
2328 			;
2329 		if (new_devs == rs->raid_disks) {
2330 			DMINFO("Superblocks created for new raid set");
2331 			set_bit(MD_ARRAY_FIRST_USE, &mddev->flags);
2332 		} else if (new_devs != rebuilds &&
2333 			   new_devs != rs->delta_disks) {
2334 			DMERR("New device injected into existing raid set without "
2335 			      "'delta_disks' or 'rebuild' parameter specified");
2336 			return -EINVAL;
2337 		}
2338 	} else if (new_devs && new_devs != rebuilds) {
2339 		DMERR("%u 'rebuild' devices cannot be injected into"
2340 		      " a raid set with %u other first-time devices",
2341 		      rebuilds, new_devs);
2342 		return -EINVAL;
2343 	} else if (rebuilds) {
2344 		if (rebuild_and_new && rebuilds != rebuild_and_new) {
2345 			DMERR("new device%s provided without 'rebuild'",
2346 			      new_devs > 1 ? "s" : "");
2347 			return -EINVAL;
2348 		} else if (rs_is_recovering(rs)) {
2349 			DMERR("'rebuild' specified while raid set is not in-sync (recovery_cp=%llu)",
2350 			      (unsigned long long) mddev->recovery_cp);
2351 			return -EINVAL;
2352 		} else if (rs_is_reshaping(rs)) {
2353 			DMERR("'rebuild' specified while raid set is being reshaped (reshape_position=%llu)",
2354 			      (unsigned long long) mddev->reshape_position);
2355 			return -EINVAL;
2356 		}
2357 	}
2358 
2359 	/*
2360 	 * Now we set the Faulty bit for those devices that are
2361 	 * recorded in the superblock as failed.
2362 	 */
2363 	sb_retrieve_failed_devices(sb, failed_devices);
2364 	rdev_for_each(r, mddev) {
2365 		if (test_bit(Journal, &rdev->flags) ||
2366 		    !r->sb_page)
2367 			continue;
2368 		sb2 = page_address(r->sb_page);
2369 		sb2->failed_devices = 0;
2370 		memset(sb2->extended_failed_devices, 0, sizeof(sb2->extended_failed_devices));
2371 
2372 		/*
2373 		 * Check for any device re-ordering.
2374 		 */
2375 		if (!test_bit(FirstUse, &r->flags) && (r->raid_disk >= 0)) {
2376 			role = le32_to_cpu(sb2->array_position);
2377 			if (role < 0)
2378 				continue;
2379 
2380 			if (role != r->raid_disk) {
2381 				if (rs_is_raid10(rs) && __is_raid10_near(mddev->layout)) {
2382 					if (mddev->raid_disks % __raid10_near_copies(mddev->layout) ||
2383 					    rs->raid_disks % rs->raid10_copies) {
2384 						rs->ti->error =
2385 							"Cannot change raid10 near set to odd # of devices!";
2386 						return -EINVAL;
2387 					}
2388 
2389 					sb2->array_position = cpu_to_le32(r->raid_disk);
2390 
2391 				} else if (!(rs_is_raid10(rs) && rt_is_raid0(rs->raid_type)) &&
2392 					   !(rs_is_raid0(rs) && rt_is_raid10(rs->raid_type)) &&
2393 					   !rt_is_raid1(rs->raid_type)) {
2394 					rs->ti->error = "Cannot change device positions in raid set";
2395 					return -EINVAL;
2396 				}
2397 
2398 				DMINFO("raid device #%d now at position #%d", role, r->raid_disk);
2399 			}
2400 
2401 			/*
2402 			 * Partial recovery is performed on
2403 			 * returning failed devices.
2404 			 */
2405 			if (test_bit(role, (void *) failed_devices))
2406 				set_bit(Faulty, &r->flags);
2407 		}
2408 	}
2409 
2410 	return 0;
2411 }
2412 
2413 static int super_validate(struct raid_set *rs, struct md_rdev *rdev)
2414 {
2415 	struct mddev *mddev = &rs->md;
2416 	struct dm_raid_superblock *sb;
2417 
2418 	if (rs_is_raid0(rs) || !rdev->sb_page || rdev->raid_disk < 0)
2419 		return 0;
2420 
2421 	sb = page_address(rdev->sb_page);
2422 
2423 	/*
2424 	 * If mddev->events is not set, we know we have not yet initialized
2425 	 * the array.
2426 	 */
2427 	if (!mddev->events && super_init_validation(rs, rdev))
2428 		return -EINVAL;
2429 
2430 	if (le32_to_cpu(sb->compat_features) &&
2431 	    le32_to_cpu(sb->compat_features) != FEATURE_FLAG_SUPPORTS_V190) {
2432 		rs->ti->error = "Unable to assemble array: Unknown flag(s) in compatible feature flags";
2433 		return -EINVAL;
2434 	}
2435 
2436 	if (sb->incompat_features) {
2437 		rs->ti->error = "Unable to assemble array: No incompatible feature flags supported yet";
2438 		return -EINVAL;
2439 	}
2440 
2441 	/* Enable bitmap creation for RAID levels != 0 */
2442 	mddev->bitmap_info.offset = rt_is_raid0(rs->raid_type) ? 0 : to_sector(4096);
2443 	mddev->bitmap_info.default_offset = mddev->bitmap_info.offset;
2444 
2445 	if (!test_and_clear_bit(FirstUse, &rdev->flags)) {
2446 		/*
2447 		 * Retrieve rdev size stored in superblock to be prepared for shrink.
2448 		 * Check extended superblock members are present otherwise the size
2449 		 * will not be set!
2450 		 */
2451 		if (le32_to_cpu(sb->compat_features) & FEATURE_FLAG_SUPPORTS_V190)
2452 			rdev->sectors = le64_to_cpu(sb->sectors);
2453 
2454 		rdev->recovery_offset = le64_to_cpu(sb->disk_recovery_offset);
2455 		if (rdev->recovery_offset == MaxSector)
2456 			set_bit(In_sync, &rdev->flags);
2457 		/*
2458 		 * If no reshape in progress -> we're recovering single
2459 		 * disk(s) and have to set the device(s) to out-of-sync
2460 		 */
2461 		else if (!rs_is_reshaping(rs))
2462 			clear_bit(In_sync, &rdev->flags); /* Mandatory for recovery */
2463 	}
2464 
2465 	/*
2466 	 * If a device comes back, set it as not In_sync and no longer faulty.
2467 	 */
2468 	if (test_and_clear_bit(Faulty, &rdev->flags)) {
2469 		rdev->recovery_offset = 0;
2470 		clear_bit(In_sync, &rdev->flags);
2471 		rdev->saved_raid_disk = rdev->raid_disk;
2472 	}
2473 
2474 	/* Reshape support -> restore repective data offsets */
2475 	rdev->data_offset = le64_to_cpu(sb->data_offset);
2476 	rdev->new_data_offset = le64_to_cpu(sb->new_data_offset);
2477 
2478 	return 0;
2479 }
2480 
2481 /*
2482  * Analyse superblocks and select the freshest.
2483  */
2484 static int analyse_superblocks(struct dm_target *ti, struct raid_set *rs)
2485 {
2486 	int r;
2487 	struct md_rdev *rdev, *freshest;
2488 	struct mddev *mddev = &rs->md;
2489 
2490 	freshest = NULL;
2491 	rdev_for_each(rdev, mddev) {
2492 		if (test_bit(Journal, &rdev->flags))
2493 			continue;
2494 
2495 		/*
2496 		 * Skipping super_load due to CTR_FLAG_SYNC will cause
2497 		 * the array to undergo initialization again as
2498 		 * though it were new.	This is the intended effect
2499 		 * of the "sync" directive.
2500 		 *
2501 		 * With reshaping capability added, we must ensure that
2502 		 * that the "sync" directive is disallowed during the reshape.
2503 		 */
2504 		if (test_bit(__CTR_FLAG_SYNC, &rs->ctr_flags))
2505 			continue;
2506 
2507 		if (!rdev->meta_bdev)
2508 			continue;
2509 
2510 		r = super_load(rdev, freshest);
2511 
2512 		switch (r) {
2513 		case 1:
2514 			freshest = rdev;
2515 			break;
2516 		case 0:
2517 			break;
2518 		default:
2519 			/* This is a failure to read the superblock from the metadata device. */
2520 			/*
2521 			 * We have to keep any raid0 data/metadata device pairs or
2522 			 * the MD raid0 personality will fail to start the array.
2523 			 */
2524 			if (rs_is_raid0(rs))
2525 				continue;
2526 
2527 			/*
2528 			 * We keep the dm_devs to be able to emit the device tuple
2529 			 * properly on the table line in raid_status() (rather than
2530 			 * mistakenly acting as if '- -' got passed into the constructor).
2531 			 *
2532 			 * The rdev has to stay on the same_set list to allow for
2533 			 * the attempt to restore faulty devices on second resume.
2534 			 */
2535 			rdev->raid_disk = rdev->saved_raid_disk = -1;
2536 			break;
2537 		}
2538 	}
2539 
2540 	if (!freshest)
2541 		return 0;
2542 
2543 	if (validate_raid_redundancy(rs)) {
2544 		rs->ti->error = "Insufficient redundancy to activate array";
2545 		return -EINVAL;
2546 	}
2547 
2548 	/*
2549 	 * Validation of the freshest device provides the source of
2550 	 * validation for the remaining devices.
2551 	 */
2552 	rs->ti->error = "Unable to assemble array: Invalid superblocks";
2553 	if (super_validate(rs, freshest))
2554 		return -EINVAL;
2555 
2556 	rdev_for_each(rdev, mddev)
2557 		if (!test_bit(Journal, &rdev->flags) &&
2558 		    rdev != freshest &&
2559 		    super_validate(rs, rdev))
2560 			return -EINVAL;
2561 	return 0;
2562 }
2563 
2564 /*
2565  * Adjust data_offset and new_data_offset on all disk members of @rs
2566  * for out of place reshaping if requested by contructor
2567  *
2568  * We need free space at the beginning of each raid disk for forward
2569  * and at the end for backward reshapes which userspace has to provide
2570  * via remapping/reordering of space.
2571  */
2572 static int rs_adjust_data_offsets(struct raid_set *rs)
2573 {
2574 	sector_t data_offset = 0, new_data_offset = 0;
2575 	struct md_rdev *rdev;
2576 
2577 	/* Constructor did not request data offset change */
2578 	if (!test_bit(__CTR_FLAG_DATA_OFFSET, &rs->ctr_flags)) {
2579 		if (!rs_is_reshapable(rs))
2580 			goto out;
2581 
2582 		return 0;
2583 	}
2584 
2585 	/* HM FIXME: get InSync raid_dev? */
2586 	rdev = &rs->dev[0].rdev;
2587 
2588 	if (rs->delta_disks < 0) {
2589 		/*
2590 		 * Removing disks (reshaping backwards):
2591 		 *
2592 		 * - before reshape: data is at offset 0 and free space
2593 		 *		     is at end of each component LV
2594 		 *
2595 		 * - after reshape: data is at offset rs->data_offset != 0 on each component LV
2596 		 */
2597 		data_offset = 0;
2598 		new_data_offset = rs->data_offset;
2599 
2600 	} else if (rs->delta_disks > 0) {
2601 		/*
2602 		 * Adding disks (reshaping forwards):
2603 		 *
2604 		 * - before reshape: data is at offset rs->data_offset != 0 and
2605 		 *		     free space is at begin of each component LV
2606 		 *
2607 		 * - after reshape: data is at offset 0 on each component LV
2608 		 */
2609 		data_offset = rs->data_offset;
2610 		new_data_offset = 0;
2611 
2612 	} else {
2613 		/*
2614 		 * User space passes in 0 for data offset after having removed reshape space
2615 		 *
2616 		 * - or - (data offset != 0)
2617 		 *
2618 		 * Changing RAID layout or chunk size -> toggle offsets
2619 		 *
2620 		 * - before reshape: data is at offset rs->data_offset 0 and
2621 		 *		     free space is at end of each component LV
2622 		 *		     -or-
2623 		 *                   data is at offset rs->data_offset != 0 and
2624 		 *		     free space is at begin of each component LV
2625 		 *
2626 		 * - after reshape: data is at offset 0 if it was at offset != 0
2627 		 *                  or at offset != 0 if it was at offset 0
2628 		 *                  on each component LV
2629 		 *
2630 		 */
2631 		data_offset = rs->data_offset ? rdev->data_offset : 0;
2632 		new_data_offset = data_offset ? 0 : rs->data_offset;
2633 		set_bit(RT_FLAG_UPDATE_SBS, &rs->runtime_flags);
2634 	}
2635 
2636 	/*
2637 	 * Make sure we got a minimum amount of free sectors per device
2638 	 */
2639 	if (rs->data_offset &&
2640 	    to_sector(i_size_read(rdev->bdev->bd_inode)) - rdev->sectors < MIN_FREE_RESHAPE_SPACE) {
2641 		rs->ti->error = data_offset ? "No space for forward reshape" :
2642 					      "No space for backward reshape";
2643 		return -ENOSPC;
2644 	}
2645 out:
2646 	/* Adjust data offsets on all rdevs but on any raid4/5/6 journal device */
2647 	rdev_for_each(rdev, &rs->md) {
2648 		if (!test_bit(Journal, &rdev->flags)) {
2649 			rdev->data_offset = data_offset;
2650 			rdev->new_data_offset = new_data_offset;
2651 		}
2652 	}
2653 
2654 	return 0;
2655 }
2656 
2657 /* Userpace reordered disks -> adjust raid_disk indexes in @rs */
2658 static void __reorder_raid_disk_indexes(struct raid_set *rs)
2659 {
2660 	int i = 0;
2661 	struct md_rdev *rdev;
2662 
2663 	rdev_for_each(rdev, &rs->md) {
2664 		if (!test_bit(Journal, &rdev->flags)) {
2665 			rdev->raid_disk = i++;
2666 			rdev->saved_raid_disk = rdev->new_raid_disk = -1;
2667 		}
2668 	}
2669 }
2670 
2671 /*
2672  * Setup @rs for takeover by a different raid level
2673  */
2674 static int rs_setup_takeover(struct raid_set *rs)
2675 {
2676 	struct mddev *mddev = &rs->md;
2677 	struct md_rdev *rdev;
2678 	unsigned int d = mddev->raid_disks = rs->raid_disks;
2679 	sector_t new_data_offset = rs->dev[0].rdev.data_offset ? 0 : rs->data_offset;
2680 
2681 	if (rt_is_raid10(rs->raid_type)) {
2682 		if (mddev->level == 0) {
2683 			/* Userpace reordered disks -> adjust raid_disk indexes */
2684 			__reorder_raid_disk_indexes(rs);
2685 
2686 			/* raid0 -> raid10_far layout */
2687 			mddev->layout = raid10_format_to_md_layout(rs, ALGORITHM_RAID10_FAR,
2688 								   rs->raid10_copies);
2689 		} else if (mddev->level == 1)
2690 			/* raid1 -> raid10_near layout */
2691 			mddev->layout = raid10_format_to_md_layout(rs, ALGORITHM_RAID10_NEAR,
2692 								   rs->raid_disks);
2693 		else
2694 			return -EINVAL;
2695 
2696 	}
2697 
2698 	clear_bit(MD_ARRAY_FIRST_USE, &mddev->flags);
2699 	mddev->recovery_cp = MaxSector;
2700 
2701 	while (d--) {
2702 		rdev = &rs->dev[d].rdev;
2703 
2704 		if (test_bit(d, (void *) rs->rebuild_disks)) {
2705 			clear_bit(In_sync, &rdev->flags);
2706 			clear_bit(Faulty, &rdev->flags);
2707 			mddev->recovery_cp = rdev->recovery_offset = 0;
2708 			/* Bitmap has to be created when we do an "up" takeover */
2709 			set_bit(MD_ARRAY_FIRST_USE, &mddev->flags);
2710 		}
2711 
2712 		rdev->new_data_offset = new_data_offset;
2713 	}
2714 
2715 	return 0;
2716 }
2717 
2718 /* Prepare @rs for reshape */
2719 static int rs_prepare_reshape(struct raid_set *rs)
2720 {
2721 	bool reshape;
2722 	struct mddev *mddev = &rs->md;
2723 
2724 	if (rs_is_raid10(rs)) {
2725 		if (rs->raid_disks != mddev->raid_disks &&
2726 		    __is_raid10_near(mddev->layout) &&
2727 		    rs->raid10_copies &&
2728 		    rs->raid10_copies != __raid10_near_copies(mddev->layout)) {
2729 			/*
2730 			 * raid disk have to be multiple of data copies to allow this conversion,
2731 			 *
2732 			 * This is actually not a reshape it is a
2733 			 * rebuild of any additional mirrors per group
2734 			 */
2735 			if (rs->raid_disks % rs->raid10_copies) {
2736 				rs->ti->error = "Can't reshape raid10 mirror groups";
2737 				return -EINVAL;
2738 			}
2739 
2740 			/* Userpace reordered disks to add/remove mirrors -> adjust raid_disk indexes */
2741 			__reorder_raid_disk_indexes(rs);
2742 			mddev->layout = raid10_format_to_md_layout(rs, ALGORITHM_RAID10_NEAR,
2743 								   rs->raid10_copies);
2744 			mddev->new_layout = mddev->layout;
2745 			reshape = false;
2746 		} else
2747 			reshape = true;
2748 
2749 	} else if (rs_is_raid456(rs))
2750 		reshape = true;
2751 
2752 	else if (rs_is_raid1(rs)) {
2753 		if (rs->delta_disks) {
2754 			/* Process raid1 via delta_disks */
2755 			mddev->degraded = rs->delta_disks < 0 ? -rs->delta_disks : rs->delta_disks;
2756 			reshape = true;
2757 		} else {
2758 			/* Process raid1 without delta_disks */
2759 			mddev->raid_disks = rs->raid_disks;
2760 			reshape = false;
2761 		}
2762 	} else {
2763 		rs->ti->error = "Called with bogus raid type";
2764 		return -EINVAL;
2765 	}
2766 
2767 	if (reshape) {
2768 		set_bit(RT_FLAG_RESHAPE_RS, &rs->runtime_flags);
2769 		set_bit(RT_FLAG_UPDATE_SBS, &rs->runtime_flags);
2770 	} else if (mddev->raid_disks < rs->raid_disks)
2771 		/* Create new superblocks and bitmaps, if any new disks */
2772 		set_bit(RT_FLAG_UPDATE_SBS, &rs->runtime_flags);
2773 
2774 	return 0;
2775 }
2776 
2777 /*
2778  *
2779  * - change raid layout
2780  * - change chunk size
2781  * - add disks
2782  * - remove disks
2783  */
2784 static int rs_setup_reshape(struct raid_set *rs)
2785 {
2786 	int r = 0;
2787 	unsigned int cur_raid_devs, d;
2788 	struct mddev *mddev = &rs->md;
2789 	struct md_rdev *rdev;
2790 
2791 	mddev->delta_disks = rs->delta_disks;
2792 	cur_raid_devs = mddev->raid_disks;
2793 
2794 	/* Ignore impossible layout change whilst adding/removing disks */
2795 	if (mddev->delta_disks &&
2796 	    mddev->layout != mddev->new_layout) {
2797 		DMINFO("Ignoring invalid layout change with delta_disks=%d", rs->delta_disks);
2798 		mddev->new_layout = mddev->layout;
2799 	}
2800 
2801 	/*
2802 	 * Adjust array size:
2803 	 *
2804 	 * - in case of adding disks, array size has
2805 	 *   to grow after the disk adding reshape,
2806 	 *   which'll hapen in the event handler;
2807 	 *   reshape will happen forward, so space has to
2808 	 *   be available at the beginning of each disk
2809 	 *
2810 	 * - in case of removing disks, array size
2811 	 *   has to shrink before starting the reshape,
2812 	 *   which'll happen here;
2813 	 *   reshape will happen backward, so space has to
2814 	 *   be available at the end of each disk
2815 	 *
2816 	 * - data_offset and new_data_offset are
2817 	 *   adjusted for aforementioned out of place
2818 	 *   reshaping based on userspace passing in
2819 	 *   the "data_offset <sectors>" key/value
2820 	 *   pair via the constructor
2821 	 */
2822 
2823 	/* Add disk(s) */
2824 	if (rs->delta_disks > 0) {
2825 		/* Prepare disks for check in raid4/5/6/10 {check|start}_reshape */
2826 		for (d = cur_raid_devs; d < rs->raid_disks; d++) {
2827 			rdev = &rs->dev[d].rdev;
2828 			clear_bit(In_sync, &rdev->flags);
2829 
2830 			/*
2831 			 * save_raid_disk needs to be -1, or recovery_offset will be set to 0
2832 			 * by md, which'll store that erroneously in the superblock on reshape
2833 			 */
2834 			rdev->saved_raid_disk = -1;
2835 			rdev->raid_disk = d;
2836 
2837 			rdev->sectors = mddev->dev_sectors;
2838 			rdev->recovery_offset = rs_is_raid1(rs) ? 0 : MaxSector;
2839 		}
2840 
2841 		mddev->reshape_backwards = 0; /* adding disks -> forward reshape */
2842 
2843 	/* Remove disk(s) */
2844 	} else if (rs->delta_disks < 0) {
2845 		r = rs_set_dev_and_array_sectors(rs, true);
2846 		mddev->reshape_backwards = 1; /* removing disk(s) -> backward reshape */
2847 
2848 	/* Change layout and/or chunk size */
2849 	} else {
2850 		/*
2851 		 * Reshape layout (e.g. raid5_ls -> raid5_n) and/or chunk size:
2852 		 *
2853 		 * keeping number of disks and do layout change ->
2854 		 *
2855 		 * toggle reshape_backward depending on data_offset:
2856 		 *
2857 		 * - free space upfront -> reshape forward
2858 		 *
2859 		 * - free space at the end -> reshape backward
2860 		 *
2861 		 *
2862 		 * This utilizes free reshape space avoiding the need
2863 		 * for userspace to move (parts of) LV segments in
2864 		 * case of layout/chunksize change  (for disk
2865 		 * adding/removing reshape space has to be at
2866 		 * the proper address (see above with delta_disks):
2867 		 *
2868 		 * add disk(s)   -> begin
2869 		 * remove disk(s)-> end
2870 		 */
2871 		mddev->reshape_backwards = rs->dev[0].rdev.data_offset ? 0 : 1;
2872 	}
2873 
2874 	return r;
2875 }
2876 
2877 /*
2878  * Enable/disable discard support on RAID set depending on
2879  * RAID level and discard properties of underlying RAID members.
2880  */
2881 static void configure_discard_support(struct raid_set *rs)
2882 {
2883 	int i;
2884 	bool raid456;
2885 	struct dm_target *ti = rs->ti;
2886 
2887 	/* Assume discards not supported until after checks below. */
2888 	ti->discards_supported = false;
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 	/* All RAID members properly support discards */
2915 	ti->discards_supported = true;
2916 
2917 	/*
2918 	 * RAID1 and RAID10 personalities require bio splitting,
2919 	 * RAID0/4/5/6 don't and process large discard bios properly.
2920 	 */
2921 	ti->split_discard_bios = !!(rs->md.level == 1 || rs->md.level == 10);
2922 	ti->num_discard_bios = 1;
2923 }
2924 
2925 /*
2926  * Construct a RAID0/1/10/4/5/6 mapping:
2927  * Args:
2928  *	<raid_type> <#raid_params> <raid_params>{0,}	\
2929  *	<#raid_devs> [<meta_dev1> <dev1>]{1,}
2930  *
2931  * <raid_params> varies by <raid_type>.	 See 'parse_raid_params' for
2932  * details on possible <raid_params>.
2933  *
2934  * Userspace is free to initialize the metadata devices, hence the superblocks to
2935  * enforce recreation based on the passed in table parameters.
2936  *
2937  */
2938 static int raid_ctr(struct dm_target *ti, unsigned int argc, char **argv)
2939 {
2940 	int r;
2941 	bool resize;
2942 	struct raid_type *rt;
2943 	unsigned int num_raid_params, num_raid_devs;
2944 	sector_t calculated_dev_sectors, rdev_sectors;
2945 	struct raid_set *rs = NULL;
2946 	const char *arg;
2947 	struct rs_layout rs_layout;
2948 	struct dm_arg_set as = { argc, argv }, as_nrd;
2949 	struct dm_arg _args[] = {
2950 		{ 0, as.argc, "Cannot understand number of raid parameters" },
2951 		{ 1, 254, "Cannot understand number of raid devices parameters" }
2952 	};
2953 
2954 	/* Must have <raid_type> */
2955 	arg = dm_shift_arg(&as);
2956 	if (!arg) {
2957 		ti->error = "No arguments";
2958 		return -EINVAL;
2959 	}
2960 
2961 	rt = get_raid_type(arg);
2962 	if (!rt) {
2963 		ti->error = "Unrecognised raid_type";
2964 		return -EINVAL;
2965 	}
2966 
2967 	/* Must have <#raid_params> */
2968 	if (dm_read_arg_group(_args, &as, &num_raid_params, &ti->error))
2969 		return -EINVAL;
2970 
2971 	/* number of raid device tupples <meta_dev data_dev> */
2972 	as_nrd = as;
2973 	dm_consume_args(&as_nrd, num_raid_params);
2974 	_args[1].max = (as_nrd.argc - 1) / 2;
2975 	if (dm_read_arg(_args + 1, &as_nrd, &num_raid_devs, &ti->error))
2976 		return -EINVAL;
2977 
2978 	if (!__within_range(num_raid_devs, 1, MAX_RAID_DEVICES)) {
2979 		ti->error = "Invalid number of supplied raid devices";
2980 		return -EINVAL;
2981 	}
2982 
2983 	rs = raid_set_alloc(ti, rt, num_raid_devs);
2984 	if (IS_ERR(rs))
2985 		return PTR_ERR(rs);
2986 
2987 	r = parse_raid_params(rs, &as, num_raid_params);
2988 	if (r)
2989 		goto bad;
2990 
2991 	r = parse_dev_params(rs, &as);
2992 	if (r)
2993 		goto bad;
2994 
2995 	rs->md.sync_super = super_sync;
2996 
2997 	/*
2998 	 * Calculate ctr requested array and device sizes to allow
2999 	 * for superblock analysis needing device sizes defined.
3000 	 *
3001 	 * Any existing superblock will overwrite the array and device sizes
3002 	 */
3003 	r = rs_set_dev_and_array_sectors(rs, false);
3004 	if (r)
3005 		goto bad;
3006 
3007 	calculated_dev_sectors = rs->md.dev_sectors;
3008 
3009 	/*
3010 	 * Backup any new raid set level, layout, ...
3011 	 * requested to be able to compare to superblock
3012 	 * members for conversion decisions.
3013 	 */
3014 	rs_config_backup(rs, &rs_layout);
3015 
3016 	r = analyse_superblocks(ti, rs);
3017 	if (r)
3018 		goto bad;
3019 
3020 	rdev_sectors = __rdev_sectors(rs);
3021 	if (!rdev_sectors) {
3022 		ti->error = "Invalid rdev size";
3023 		r = -EINVAL;
3024 		goto bad;
3025 	}
3026 
3027 	resize = calculated_dev_sectors != rdev_sectors;
3028 
3029 	INIT_WORK(&rs->md.event_work, do_table_event);
3030 	ti->private = rs;
3031 	ti->num_flush_bios = 1;
3032 
3033 	/* Restore any requested new layout for conversion decision */
3034 	rs_config_restore(rs, &rs_layout);
3035 
3036 	/*
3037 	 * Now that we have any superblock metadata available,
3038 	 * check for new, recovering, reshaping, to be taken over,
3039 	 * to be reshaped or an existing, unchanged raid set to
3040 	 * run in sequence.
3041 	 */
3042 	if (test_bit(MD_ARRAY_FIRST_USE, &rs->md.flags)) {
3043 		/* A new raid6 set has to be recovered to ensure proper parity and Q-Syndrome */
3044 		if (rs_is_raid6(rs) &&
3045 		    test_bit(__CTR_FLAG_NOSYNC, &rs->ctr_flags)) {
3046 			ti->error = "'nosync' not allowed for new raid6 set";
3047 			r = -EINVAL;
3048 			goto bad;
3049 		}
3050 		rs_setup_recovery(rs, 0);
3051 		set_bit(RT_FLAG_UPDATE_SBS, &rs->runtime_flags);
3052 		rs_set_new(rs);
3053 	} else if (rs_is_recovering(rs)) {
3054 		/* A recovering raid set may be resized */
3055 		; /* skip setup rs */
3056 	} else if (rs_is_reshaping(rs)) {
3057 		/* Have to reject size change request during reshape */
3058 		if (resize) {
3059 			ti->error = "Can't resize a reshaping raid set";
3060 			r = -EPERM;
3061 			goto bad;
3062 		}
3063 		/* skip setup rs */
3064 	} else if (rs_takeover_requested(rs)) {
3065 		if (rs_is_reshaping(rs)) {
3066 			ti->error = "Can't takeover a reshaping raid set";
3067 			r = -EPERM;
3068 			goto bad;
3069 		}
3070 
3071 		/* We can't takeover a journaled raid4/5/6 */
3072 		if (test_bit(__CTR_FLAG_JOURNAL_DEV, &rs->ctr_flags)) {
3073 			ti->error = "Can't takeover a journaled raid4/5/6 set";
3074 			r = -EPERM;
3075 			goto bad;
3076 		}
3077 
3078 		/*
3079 		 * If a takeover is needed, userspace sets any additional
3080 		 * devices to rebuild and we can check for a valid request here.
3081 		 *
3082 		 * If acceptible, set the level to the new requested
3083 		 * one, prohibit requesting recovery, allow the raid
3084 		 * set to run and store superblocks during resume.
3085 		 */
3086 		r = rs_check_takeover(rs);
3087 		if (r)
3088 			goto bad;
3089 
3090 		r = rs_setup_takeover(rs);
3091 		if (r)
3092 			goto bad;
3093 
3094 		set_bit(RT_FLAG_UPDATE_SBS, &rs->runtime_flags);
3095 		/* Takeover ain't recovery, so disable recovery */
3096 		rs_setup_recovery(rs, MaxSector);
3097 		rs_set_new(rs);
3098 	} else if (rs_reshape_requested(rs)) {
3099 		/*
3100 		 * No need to check for 'ongoing' takeover here, because takeover
3101 		 * is an instant operation as oposed to an ongoing reshape.
3102 		 */
3103 
3104 		/* We can't reshape a journaled raid4/5/6 */
3105 		if (test_bit(__CTR_FLAG_JOURNAL_DEV, &rs->ctr_flags)) {
3106 			ti->error = "Can't reshape a journaled raid4/5/6 set";
3107 			r = -EPERM;
3108 			goto bad;
3109 		}
3110 
3111 		/*
3112 		  * We can only prepare for a reshape here, because the
3113 		  * raid set needs to run to provide the repective reshape
3114 		  * check functions via its MD personality instance.
3115 		  *
3116 		  * So do the reshape check after md_run() succeeded.
3117 		  */
3118 		r = rs_prepare_reshape(rs);
3119 		if (r)
3120 			return r;
3121 
3122 		/* Reshaping ain't recovery, so disable recovery */
3123 		rs_setup_recovery(rs, MaxSector);
3124 		rs_set_cur(rs);
3125 	} else {
3126 		/* May not set recovery when a device rebuild is requested */
3127 		if (test_bit(__CTR_FLAG_REBUILD, &rs->ctr_flags)) {
3128 			rs_setup_recovery(rs, MaxSector);
3129 			set_bit(RT_FLAG_UPDATE_SBS, &rs->runtime_flags);
3130 		} else
3131 			rs_setup_recovery(rs, test_bit(__CTR_FLAG_SYNC, &rs->ctr_flags) ?
3132 					      0 : (resize ? calculated_dev_sectors : MaxSector));
3133 		rs_set_cur(rs);
3134 	}
3135 
3136 	/* If constructor requested it, change data and new_data offsets */
3137 	r = rs_adjust_data_offsets(rs);
3138 	if (r)
3139 		goto bad;
3140 
3141 	/* Start raid set read-only and assumed clean to change in raid_resume() */
3142 	rs->md.ro = 1;
3143 	rs->md.in_sync = 1;
3144 	set_bit(MD_RECOVERY_FROZEN, &rs->md.recovery);
3145 
3146 	/* Has to be held on running the array */
3147 	mddev_lock_nointr(&rs->md);
3148 	r = md_run(&rs->md);
3149 	rs->md.in_sync = 0; /* Assume already marked dirty */
3150 
3151 	if (r) {
3152 		ti->error = "Failed to run raid array";
3153 		mddev_unlock(&rs->md);
3154 		goto bad;
3155 	}
3156 
3157 	rs->callbacks.congested_fn = raid_is_congested;
3158 	dm_table_add_target_callbacks(ti->table, &rs->callbacks);
3159 
3160 	/* If raid4/5/6 journal mode explictely requested (only possible with journal dev) -> set it */
3161 	if (test_bit(__CTR_FLAG_JOURNAL_MODE, &rs->ctr_flags)) {
3162 		r = r5c_journal_mode_set(&rs->md, rs->journal_dev.mode);
3163 		if (r) {
3164 			ti->error = "Failed to set raid4/5/6 journal mode";
3165 			mddev_unlock(&rs->md);
3166 			goto bad_journal_mode_set;
3167 		}
3168 	}
3169 
3170 	mddev_suspend(&rs->md);
3171 
3172 	/* Try to adjust the raid4/5/6 stripe cache size to the stripe size */
3173 	if (rs_is_raid456(rs)) {
3174 		r = rs_set_raid456_stripe_cache(rs);
3175 		if (r)
3176 			goto bad_stripe_cache;
3177 	}
3178 
3179 	/* Now do an early reshape check */
3180 	if (test_bit(RT_FLAG_RESHAPE_RS, &rs->runtime_flags)) {
3181 		r = rs_check_reshape(rs);
3182 		if (r)
3183 			goto bad_check_reshape;
3184 
3185 		/* Restore new, ctr requested layout to perform check */
3186 		rs_config_restore(rs, &rs_layout);
3187 
3188 		if (rs->md.pers->start_reshape) {
3189 			r = rs->md.pers->check_reshape(&rs->md);
3190 			if (r) {
3191 				ti->error = "Reshape check failed";
3192 				goto bad_check_reshape;
3193 			}
3194 		}
3195 	}
3196 
3197 	/* Disable/enable discard support on raid set. */
3198 	configure_discard_support(rs);
3199 
3200 	mddev_unlock(&rs->md);
3201 	return 0;
3202 
3203 bad_journal_mode_set:
3204 bad_stripe_cache:
3205 bad_check_reshape:
3206 	md_stop(&rs->md);
3207 bad:
3208 	raid_set_free(rs);
3209 
3210 	return r;
3211 }
3212 
3213 static void raid_dtr(struct dm_target *ti)
3214 {
3215 	struct raid_set *rs = ti->private;
3216 
3217 	list_del_init(&rs->callbacks.list);
3218 	md_stop(&rs->md);
3219 	raid_set_free(rs);
3220 }
3221 
3222 static int raid_map(struct dm_target *ti, struct bio *bio)
3223 {
3224 	struct raid_set *rs = ti->private;
3225 	struct mddev *mddev = &rs->md;
3226 
3227 	/*
3228 	 * If we're reshaping to add disk(s)), ti->len and
3229 	 * mddev->array_sectors will differ during the process
3230 	 * (ti->len > mddev->array_sectors), so we have to requeue
3231 	 * bios with addresses > mddev->array_sectors here or
3232 	 * there will occur accesses past EOD of the component
3233 	 * data images thus erroring the raid set.
3234 	 */
3235 	if (unlikely(bio_end_sector(bio) > mddev->array_sectors))
3236 		return DM_MAPIO_REQUEUE;
3237 
3238 	mddev->pers->make_request(mddev, bio);
3239 
3240 	return DM_MAPIO_SUBMITTED;
3241 }
3242 
3243 /* Return string describing the current sync action of @mddev */
3244 static const char *decipher_sync_action(struct mddev *mddev)
3245 {
3246 	if (test_bit(MD_RECOVERY_FROZEN, &mddev->recovery))
3247 		return "frozen";
3248 
3249 	if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery) ||
3250 	    (!mddev->ro && test_bit(MD_RECOVERY_NEEDED, &mddev->recovery))) {
3251 		if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery))
3252 			return "reshape";
3253 
3254 		if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) {
3255 			if (!test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery))
3256 				return "resync";
3257 			else if (test_bit(MD_RECOVERY_CHECK, &mddev->recovery))
3258 				return "check";
3259 			return "repair";
3260 		}
3261 
3262 		if (test_bit(MD_RECOVERY_RECOVER, &mddev->recovery))
3263 			return "recover";
3264 	}
3265 
3266 	return "idle";
3267 }
3268 
3269 /*
3270  * Return status string for @rdev
3271  *
3272  * Status characters:
3273  *
3274  *  'D' = Dead/Failed raid set component or raid4/5/6 journal device
3275  *  'a' = Alive but not in-sync raid set component _or_ alive raid4/5/6 'write_back' journal device
3276  *  'A' = Alive and in-sync raid set component _or_ alive raid4/5/6 'write_through' journal device
3277  *  '-' = Non-existing device (i.e. uspace passed '- -' into the ctr)
3278  */
3279 static const char *__raid_dev_status(struct raid_set *rs, struct md_rdev *rdev, bool array_in_sync)
3280 {
3281 	if (!rdev->bdev)
3282 		return "-";
3283 	else if (test_bit(Faulty, &rdev->flags))
3284 		return "D";
3285 	else if (test_bit(Journal, &rdev->flags))
3286 		return (rs->journal_dev.mode == R5C_JOURNAL_MODE_WRITE_THROUGH) ? "A" : "a";
3287 	else if (!array_in_sync || !test_bit(In_sync, &rdev->flags))
3288 		return "a";
3289 	else
3290 		return "A";
3291 }
3292 
3293 /* Helper to return resync/reshape progress for @rs and @array_in_sync */
3294 static sector_t rs_get_progress(struct raid_set *rs,
3295 				sector_t resync_max_sectors, bool *array_in_sync)
3296 {
3297 	sector_t r, recovery_cp, curr_resync_completed;
3298 	struct mddev *mddev = &rs->md;
3299 
3300 	curr_resync_completed = mddev->curr_resync_completed ?: mddev->recovery_cp;
3301 	recovery_cp = mddev->recovery_cp;
3302 	*array_in_sync = false;
3303 
3304 	if (rs_is_raid0(rs)) {
3305 		r = resync_max_sectors;
3306 		*array_in_sync = true;
3307 
3308 	} else {
3309 		r = mddev->reshape_position;
3310 
3311 		/* Reshape is relative to the array size */
3312 		if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery) ||
3313 		    r != MaxSector) {
3314 			if (r == MaxSector) {
3315 				*array_in_sync = true;
3316 				r = resync_max_sectors;
3317 			} else {
3318 				/* Got to reverse on backward reshape */
3319 				if (mddev->reshape_backwards)
3320 					r = mddev->array_sectors - r;
3321 
3322 				/* Devide by # of data stripes */
3323 				sector_div(r, mddev_data_stripes(rs));
3324 			}
3325 
3326 		/* Sync is relative to the component device size */
3327 		} else if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery))
3328 			r = curr_resync_completed;
3329 		else
3330 			r = recovery_cp;
3331 
3332 		if (r == MaxSector) {
3333 			/*
3334 			 * Sync complete.
3335 			 */
3336 			*array_in_sync = true;
3337 			r = resync_max_sectors;
3338 		} else if (test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery)) {
3339 			/*
3340 			 * If "check" or "repair" is occurring, the raid set has
3341 			 * undergone an initial sync and the health characters
3342 			 * should not be 'a' anymore.
3343 			 */
3344 			*array_in_sync = true;
3345 		} else {
3346 			struct md_rdev *rdev;
3347 
3348 			/*
3349 			 * The raid set may be doing an initial sync, or it may
3350 			 * be rebuilding individual components.	 If all the
3351 			 * devices are In_sync, then it is the raid set that is
3352 			 * being initialized.
3353 			 */
3354 			rdev_for_each(rdev, mddev)
3355 				if (!test_bit(Journal, &rdev->flags) &&
3356 				    !test_bit(In_sync, &rdev->flags))
3357 					*array_in_sync = true;
3358 #if 0
3359 			r = 0; /* HM FIXME: TESTME: https://bugzilla.redhat.com/show_bug.cgi?id=1210637 ? */
3360 #endif
3361 		}
3362 	}
3363 
3364 	return r;
3365 }
3366 
3367 /* Helper to return @dev name or "-" if !@dev */
3368 static const char *__get_dev_name(struct dm_dev *dev)
3369 {
3370 	return dev ? dev->name : "-";
3371 }
3372 
3373 static void raid_status(struct dm_target *ti, status_type_t type,
3374 			unsigned int status_flags, char *result, unsigned int maxlen)
3375 {
3376 	struct raid_set *rs = ti->private;
3377 	struct mddev *mddev = &rs->md;
3378 	struct r5conf *conf = mddev->private;
3379 	int i, max_nr_stripes = conf ? conf->max_nr_stripes : 0;
3380 	bool array_in_sync;
3381 	unsigned int raid_param_cnt = 1; /* at least 1 for chunksize */
3382 	unsigned int sz = 0;
3383 	unsigned int rebuild_disks;
3384 	unsigned int write_mostly_params = 0;
3385 	sector_t progress, resync_max_sectors, resync_mismatches;
3386 	const char *sync_action;
3387 	struct raid_type *rt;
3388 
3389 	switch (type) {
3390 	case STATUSTYPE_INFO:
3391 		/* *Should* always succeed */
3392 		rt = get_raid_type_by_ll(mddev->new_level, mddev->new_layout);
3393 		if (!rt)
3394 			return;
3395 
3396 		DMEMIT("%s %d ", rt->name, mddev->raid_disks);
3397 
3398 		/* Access most recent mddev properties for status output */
3399 		smp_rmb();
3400 		/* Get sensible max sectors even if raid set not yet started */
3401 		resync_max_sectors = test_bit(RT_FLAG_RS_PRERESUMED, &rs->runtime_flags) ?
3402 				      mddev->resync_max_sectors : mddev->dev_sectors;
3403 		progress = rs_get_progress(rs, resync_max_sectors, &array_in_sync);
3404 		resync_mismatches = (mddev->last_sync_action && !strcasecmp(mddev->last_sync_action, "check")) ?
3405 				    atomic64_read(&mddev->resync_mismatches) : 0;
3406 		sync_action = decipher_sync_action(&rs->md);
3407 
3408 		/* HM FIXME: do we want another state char for raid0? It shows 'D'/'A'/'-' now */
3409 		for (i = 0; i < rs->raid_disks; i++)
3410 			DMEMIT(__raid_dev_status(rs, &rs->dev[i].rdev, array_in_sync));
3411 
3412 		/*
3413 		 * In-sync/Reshape ratio:
3414 		 *  The in-sync ratio shows the progress of:
3415 		 *   - Initializing the raid set
3416 		 *   - Rebuilding a subset of devices of the raid set
3417 		 *  The user can distinguish between the two by referring
3418 		 *  to the status characters.
3419 		 *
3420 		 *  The reshape ratio shows the progress of
3421 		 *  changing the raid layout or the number of
3422 		 *  disks of a raid set
3423 		 */
3424 		DMEMIT(" %llu/%llu", (unsigned long long) progress,
3425 				     (unsigned long long) resync_max_sectors);
3426 
3427 		/*
3428 		 * v1.5.0+:
3429 		 *
3430 		 * Sync action:
3431 		 *   See Documentation/device-mapper/dm-raid.txt for
3432 		 *   information on each of these states.
3433 		 */
3434 		DMEMIT(" %s", sync_action);
3435 
3436 		/*
3437 		 * v1.5.0+:
3438 		 *
3439 		 * resync_mismatches/mismatch_cnt
3440 		 *   This field shows the number of discrepancies found when
3441 		 *   performing a "check" of the raid set.
3442 		 */
3443 		DMEMIT(" %llu", (unsigned long long) resync_mismatches);
3444 
3445 		/*
3446 		 * v1.9.0+:
3447 		 *
3448 		 * data_offset (needed for out of space reshaping)
3449 		 *   This field shows the data offset into the data
3450 		 *   image LV where the first stripes data starts.
3451 		 *
3452 		 * We keep data_offset equal on all raid disks of the set,
3453 		 * so retrieving it from the first raid disk is sufficient.
3454 		 */
3455 		DMEMIT(" %llu", (unsigned long long) rs->dev[0].rdev.data_offset);
3456 
3457 		/*
3458 		 * v1.10.0+:
3459 		 */
3460 		DMEMIT(" %s", test_bit(__CTR_FLAG_JOURNAL_DEV, &rs->ctr_flags) ?
3461 			      __raid_dev_status(rs, &rs->journal_dev.rdev, 0) : "-");
3462 		break;
3463 
3464 	case STATUSTYPE_TABLE:
3465 		/* Report the table line string you would use to construct this raid set */
3466 
3467 		/* Calculate raid parameter count */
3468 		for (i = 0; i < rs->raid_disks; i++)
3469 			if (test_bit(WriteMostly, &rs->dev[i].rdev.flags))
3470 				write_mostly_params += 2;
3471 		rebuild_disks = memweight(rs->rebuild_disks, DISKS_ARRAY_ELEMS * sizeof(*rs->rebuild_disks));
3472 		raid_param_cnt += rebuild_disks * 2 +
3473 				  write_mostly_params +
3474 				  hweight32(rs->ctr_flags & CTR_FLAG_OPTIONS_NO_ARGS) +
3475 				  hweight32(rs->ctr_flags & CTR_FLAG_OPTIONS_ONE_ARG) * 2 +
3476 				  (test_bit(__CTR_FLAG_JOURNAL_DEV, &rs->ctr_flags) ? 2 : 0) +
3477 				  (test_bit(__CTR_FLAG_JOURNAL_MODE, &rs->ctr_flags) ? 2 : 0);
3478 
3479 		/* Emit table line */
3480 		/* This has to be in the documented order for userspace! */
3481 		DMEMIT("%s %u %u", rs->raid_type->name, raid_param_cnt, mddev->new_chunk_sectors);
3482 		if (test_bit(__CTR_FLAG_SYNC, &rs->ctr_flags))
3483 			DMEMIT(" %s", dm_raid_arg_name_by_flag(CTR_FLAG_SYNC));
3484 		if (test_bit(__CTR_FLAG_NOSYNC, &rs->ctr_flags))
3485 			DMEMIT(" %s", dm_raid_arg_name_by_flag(CTR_FLAG_NOSYNC));
3486 		if (rebuild_disks)
3487 			for (i = 0; i < rs->raid_disks; i++)
3488 				if (test_bit(rs->dev[i].rdev.raid_disk, (void *) rs->rebuild_disks))
3489 					DMEMIT(" %s %u", dm_raid_arg_name_by_flag(CTR_FLAG_REBUILD),
3490 							 rs->dev[i].rdev.raid_disk);
3491 		if (test_bit(__CTR_FLAG_DAEMON_SLEEP, &rs->ctr_flags))
3492 			DMEMIT(" %s %lu", dm_raid_arg_name_by_flag(CTR_FLAG_DAEMON_SLEEP),
3493 					  mddev->bitmap_info.daemon_sleep);
3494 		if (test_bit(__CTR_FLAG_MIN_RECOVERY_RATE, &rs->ctr_flags))
3495 			DMEMIT(" %s %d", dm_raid_arg_name_by_flag(CTR_FLAG_MIN_RECOVERY_RATE),
3496 					 mddev->sync_speed_min);
3497 		if (test_bit(__CTR_FLAG_MAX_RECOVERY_RATE, &rs->ctr_flags))
3498 			DMEMIT(" %s %d", dm_raid_arg_name_by_flag(CTR_FLAG_MAX_RECOVERY_RATE),
3499 					 mddev->sync_speed_max);
3500 		if (write_mostly_params)
3501 			for (i = 0; i < rs->raid_disks; i++)
3502 				if (test_bit(WriteMostly, &rs->dev[i].rdev.flags))
3503 					DMEMIT(" %s %d", dm_raid_arg_name_by_flag(CTR_FLAG_WRITE_MOSTLY),
3504 					       rs->dev[i].rdev.raid_disk);
3505 		if (test_bit(__CTR_FLAG_MAX_WRITE_BEHIND, &rs->ctr_flags))
3506 			DMEMIT(" %s %lu", dm_raid_arg_name_by_flag(CTR_FLAG_MAX_WRITE_BEHIND),
3507 					  mddev->bitmap_info.max_write_behind);
3508 		if (test_bit(__CTR_FLAG_STRIPE_CACHE, &rs->ctr_flags))
3509 			DMEMIT(" %s %d", dm_raid_arg_name_by_flag(CTR_FLAG_STRIPE_CACHE),
3510 					 max_nr_stripes);
3511 		if (test_bit(__CTR_FLAG_REGION_SIZE, &rs->ctr_flags))
3512 			DMEMIT(" %s %llu", dm_raid_arg_name_by_flag(CTR_FLAG_REGION_SIZE),
3513 					   (unsigned long long) to_sector(mddev->bitmap_info.chunksize));
3514 		if (test_bit(__CTR_FLAG_RAID10_COPIES, &rs->ctr_flags))
3515 			DMEMIT(" %s %d", dm_raid_arg_name_by_flag(CTR_FLAG_RAID10_COPIES),
3516 					 raid10_md_layout_to_copies(mddev->layout));
3517 		if (test_bit(__CTR_FLAG_RAID10_FORMAT, &rs->ctr_flags))
3518 			DMEMIT(" %s %s", dm_raid_arg_name_by_flag(CTR_FLAG_RAID10_FORMAT),
3519 					 raid10_md_layout_to_format(mddev->layout));
3520 		if (test_bit(__CTR_FLAG_DELTA_DISKS, &rs->ctr_flags))
3521 			DMEMIT(" %s %d", dm_raid_arg_name_by_flag(CTR_FLAG_DELTA_DISKS),
3522 					 max(rs->delta_disks, mddev->delta_disks));
3523 		if (test_bit(__CTR_FLAG_DATA_OFFSET, &rs->ctr_flags))
3524 			DMEMIT(" %s %llu", dm_raid_arg_name_by_flag(CTR_FLAG_DATA_OFFSET),
3525 					   (unsigned long long) rs->data_offset);
3526 		if (test_bit(__CTR_FLAG_JOURNAL_DEV, &rs->ctr_flags))
3527 			DMEMIT(" %s %s", dm_raid_arg_name_by_flag(CTR_FLAG_JOURNAL_DEV),
3528 					__get_dev_name(rs->journal_dev.dev));
3529 		if (test_bit(__CTR_FLAG_JOURNAL_MODE, &rs->ctr_flags))
3530 			DMEMIT(" %s %s", dm_raid_arg_name_by_flag(CTR_FLAG_JOURNAL_MODE),
3531 					 md_journal_mode_to_dm_raid(rs->journal_dev.mode));
3532 		DMEMIT(" %d", rs->raid_disks);
3533 		for (i = 0; i < rs->raid_disks; i++)
3534 			DMEMIT(" %s %s", __get_dev_name(rs->dev[i].meta_dev),
3535 					 __get_dev_name(rs->dev[i].data_dev));
3536 	}
3537 }
3538 
3539 static int raid_message(struct dm_target *ti, unsigned int argc, char **argv)
3540 {
3541 	struct raid_set *rs = ti->private;
3542 	struct mddev *mddev = &rs->md;
3543 
3544 	if (!mddev->pers || !mddev->pers->sync_request)
3545 		return -EINVAL;
3546 
3547 	if (!strcasecmp(argv[0], "frozen"))
3548 		set_bit(MD_RECOVERY_FROZEN, &mddev->recovery);
3549 	else
3550 		clear_bit(MD_RECOVERY_FROZEN, &mddev->recovery);
3551 
3552 	if (!strcasecmp(argv[0], "idle") || !strcasecmp(argv[0], "frozen")) {
3553 		if (mddev->sync_thread) {
3554 			set_bit(MD_RECOVERY_INTR, &mddev->recovery);
3555 			md_reap_sync_thread(mddev);
3556 		}
3557 	} else if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery) ||
3558 		   test_bit(MD_RECOVERY_NEEDED, &mddev->recovery))
3559 		return -EBUSY;
3560 	else if (!strcasecmp(argv[0], "resync"))
3561 		; /* MD_RECOVERY_NEEDED set below */
3562 	else if (!strcasecmp(argv[0], "recover"))
3563 		set_bit(MD_RECOVERY_RECOVER, &mddev->recovery);
3564 	else {
3565 		if (!strcasecmp(argv[0], "check")) {
3566 			set_bit(MD_RECOVERY_CHECK, &mddev->recovery);
3567 			set_bit(MD_RECOVERY_REQUESTED, &mddev->recovery);
3568 			set_bit(MD_RECOVERY_SYNC, &mddev->recovery);
3569 		} else if (!strcasecmp(argv[0], "repair")) {
3570 			set_bit(MD_RECOVERY_REQUESTED, &mddev->recovery);
3571 			set_bit(MD_RECOVERY_SYNC, &mddev->recovery);
3572 		} else
3573 			return -EINVAL;
3574 	}
3575 	if (mddev->ro == 2) {
3576 		/* A write to sync_action is enough to justify
3577 		 * canceling read-auto mode
3578 		 */
3579 		mddev->ro = 0;
3580 		if (!mddev->suspended && mddev->sync_thread)
3581 			md_wakeup_thread(mddev->sync_thread);
3582 	}
3583 	set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
3584 	if (!mddev->suspended && mddev->thread)
3585 		md_wakeup_thread(mddev->thread);
3586 
3587 	return 0;
3588 }
3589 
3590 static int raid_iterate_devices(struct dm_target *ti,
3591 				iterate_devices_callout_fn fn, void *data)
3592 {
3593 	struct raid_set *rs = ti->private;
3594 	unsigned int i;
3595 	int r = 0;
3596 
3597 	for (i = 0; !r && i < rs->md.raid_disks; i++)
3598 		if (rs->dev[i].data_dev)
3599 			r = fn(ti,
3600 				 rs->dev[i].data_dev,
3601 				 0, /* No offset on data devs */
3602 				 rs->md.dev_sectors,
3603 				 data);
3604 
3605 	return r;
3606 }
3607 
3608 static void raid_io_hints(struct dm_target *ti, struct queue_limits *limits)
3609 {
3610 	struct raid_set *rs = ti->private;
3611 	unsigned int chunk_size = to_bytes(rs->md.chunk_sectors);
3612 
3613 	blk_limits_io_min(limits, chunk_size);
3614 	blk_limits_io_opt(limits, chunk_size * mddev_data_stripes(rs));
3615 }
3616 
3617 static void raid_presuspend(struct dm_target *ti)
3618 {
3619 	struct raid_set *rs = ti->private;
3620 
3621 	md_stop_writes(&rs->md);
3622 }
3623 
3624 static void raid_postsuspend(struct dm_target *ti)
3625 {
3626 	struct raid_set *rs = ti->private;
3627 
3628 	if (!rs->md.suspended)
3629 		mddev_suspend(&rs->md);
3630 
3631 	rs->md.ro = 1;
3632 }
3633 
3634 static void attempt_restore_of_faulty_devices(struct raid_set *rs)
3635 {
3636 	int i;
3637 	uint64_t cleared_failed_devices[DISKS_ARRAY_ELEMS];
3638 	unsigned long flags;
3639 	bool cleared = false;
3640 	struct dm_raid_superblock *sb;
3641 	struct mddev *mddev = &rs->md;
3642 	struct md_rdev *r;
3643 
3644 	/* RAID personalities have to provide hot add/remove methods or we need to bail out. */
3645 	if (!mddev->pers || !mddev->pers->hot_add_disk || !mddev->pers->hot_remove_disk)
3646 		return;
3647 
3648 	memset(cleared_failed_devices, 0, sizeof(cleared_failed_devices));
3649 
3650 	for (i = 0; i < mddev->raid_disks; i++) {
3651 		r = &rs->dev[i].rdev;
3652 		/* HM FIXME: enhance journal device recovery processing */
3653 		if (test_bit(Journal, &r->flags))
3654 			continue;
3655 
3656 		if (test_bit(Faulty, &r->flags) &&
3657 		    r->meta_bdev && !read_disk_sb(r, r->sb_size, true)) {
3658 			DMINFO("Faulty %s device #%d has readable super block."
3659 			       "  Attempting to revive it.",
3660 			       rs->raid_type->name, i);
3661 
3662 			/*
3663 			 * Faulty bit may be set, but sometimes the array can
3664 			 * be suspended before the personalities can respond
3665 			 * by removing the device from the array (i.e. calling
3666 			 * 'hot_remove_disk').	If they haven't yet removed
3667 			 * the failed device, its 'raid_disk' number will be
3668 			 * '>= 0' - meaning we must call this function
3669 			 * ourselves.
3670 			 */
3671 			flags = r->flags;
3672 			clear_bit(In_sync, &r->flags); /* Mandatory for hot remove. */
3673 			if (r->raid_disk >= 0) {
3674 				if (mddev->pers->hot_remove_disk(mddev, r)) {
3675 					/* Failed to revive this device, try next */
3676 					r->flags = flags;
3677 					continue;
3678 				}
3679 			} else
3680 				r->raid_disk = r->saved_raid_disk = i;
3681 
3682 			clear_bit(Faulty, &r->flags);
3683 			clear_bit(WriteErrorSeen, &r->flags);
3684 
3685 			if (mddev->pers->hot_add_disk(mddev, r)) {
3686 				/* Failed to revive this device, try next */
3687 				r->raid_disk = r->saved_raid_disk = -1;
3688 				r->flags = flags;
3689 			} else {
3690 				clear_bit(In_sync, &r->flags);
3691 				r->recovery_offset = 0;
3692 				set_bit(i, (void *) cleared_failed_devices);
3693 				cleared = true;
3694 			}
3695 		}
3696 	}
3697 
3698 	/* If any failed devices could be cleared, update all sbs failed_devices bits */
3699 	if (cleared) {
3700 		uint64_t failed_devices[DISKS_ARRAY_ELEMS];
3701 
3702 		rdev_for_each(r, &rs->md) {
3703 			if (test_bit(Journal, &r->flags))
3704 				continue;
3705 
3706 			sb = page_address(r->sb_page);
3707 			sb_retrieve_failed_devices(sb, failed_devices);
3708 
3709 			for (i = 0; i < DISKS_ARRAY_ELEMS; i++)
3710 				failed_devices[i] &= ~cleared_failed_devices[i];
3711 
3712 			sb_update_failed_devices(sb, failed_devices);
3713 		}
3714 	}
3715 }
3716 
3717 static int __load_dirty_region_bitmap(struct raid_set *rs)
3718 {
3719 	int r = 0;
3720 
3721 	/* Try loading the bitmap unless "raid0", which does not have one */
3722 	if (!rs_is_raid0(rs) &&
3723 	    !test_and_set_bit(RT_FLAG_RS_BITMAP_LOADED, &rs->runtime_flags)) {
3724 		r = bitmap_load(&rs->md);
3725 		if (r)
3726 			DMERR("Failed to load bitmap");
3727 	}
3728 
3729 	return r;
3730 }
3731 
3732 /* Enforce updating all superblocks */
3733 static void rs_update_sbs(struct raid_set *rs)
3734 {
3735 	struct mddev *mddev = &rs->md;
3736 	int ro = mddev->ro;
3737 
3738 	set_bit(MD_SB_CHANGE_DEVS, &mddev->sb_flags);
3739 	mddev->ro = 0;
3740 	md_update_sb(mddev, 1);
3741 	mddev->ro = ro;
3742 }
3743 
3744 /*
3745  * Reshape changes raid algorithm of @rs to new one within personality
3746  * (e.g. raid6_zr -> raid6_nc), changes stripe size, adds/removes
3747  * disks from a raid set thus growing/shrinking it or resizes the set
3748  *
3749  * Call mddev_lock_nointr() before!
3750  */
3751 static int rs_start_reshape(struct raid_set *rs)
3752 {
3753 	int r;
3754 	struct mddev *mddev = &rs->md;
3755 	struct md_personality *pers = mddev->pers;
3756 
3757 	r = rs_setup_reshape(rs);
3758 	if (r)
3759 		return r;
3760 
3761 	/* Need to be resumed to be able to start reshape, recovery is frozen until raid_resume() though */
3762 	if (mddev->suspended)
3763 		mddev_resume(mddev);
3764 
3765 	/*
3766 	 * Check any reshape constraints enforced by the personalility
3767 	 *
3768 	 * May as well already kick the reshape off so that * pers->start_reshape() becomes optional.
3769 	 */
3770 	r = pers->check_reshape(mddev);
3771 	if (r) {
3772 		rs->ti->error = "pers->check_reshape() failed";
3773 		return r;
3774 	}
3775 
3776 	/*
3777 	 * Personality may not provide start reshape method in which
3778 	 * case check_reshape above has already covered everything
3779 	 */
3780 	if (pers->start_reshape) {
3781 		r = pers->start_reshape(mddev);
3782 		if (r) {
3783 			rs->ti->error = "pers->start_reshape() failed";
3784 			return r;
3785 		}
3786 	}
3787 
3788 	/* Suspend because a resume will happen in raid_resume() */
3789 	if (!mddev->suspended)
3790 		mddev_suspend(mddev);
3791 
3792 	/*
3793 	 * Now reshape got set up, update superblocks to
3794 	 * reflect the fact so that a table reload will
3795 	 * access proper superblock content in the ctr.
3796 	 */
3797 	rs_update_sbs(rs);
3798 
3799 	return 0;
3800 }
3801 
3802 static int raid_preresume(struct dm_target *ti)
3803 {
3804 	int r;
3805 	struct raid_set *rs = ti->private;
3806 	struct mddev *mddev = &rs->md;
3807 
3808 	/* This is a resume after a suspend of the set -> it's already started */
3809 	if (test_and_set_bit(RT_FLAG_RS_PRERESUMED, &rs->runtime_flags))
3810 		return 0;
3811 
3812 	/*
3813 	 * The superblocks need to be updated on disk if the
3814 	 * array is new or new devices got added (thus zeroed
3815 	 * out by userspace) or __load_dirty_region_bitmap
3816 	 * will overwrite them in core with old data or fail.
3817 	 */
3818 	if (test_bit(RT_FLAG_UPDATE_SBS, &rs->runtime_flags))
3819 		rs_update_sbs(rs);
3820 
3821 	/* Load the bitmap from disk unless raid0 */
3822 	r = __load_dirty_region_bitmap(rs);
3823 	if (r)
3824 		return r;
3825 
3826 	/* Resize bitmap to adjust to changed region size (aka MD bitmap chunksize) */
3827 	if (test_bit(RT_FLAG_RS_BITMAP_LOADED, &rs->runtime_flags) && mddev->bitmap &&
3828 	    mddev->bitmap_info.chunksize != to_bytes(rs->requested_bitmap_chunk_sectors)) {
3829 		r = bitmap_resize(mddev->bitmap, mddev->dev_sectors,
3830 				  to_bytes(rs->requested_bitmap_chunk_sectors), 0);
3831 		if (r)
3832 			DMERR("Failed to resize bitmap");
3833 	}
3834 
3835 	/* Check for any resize/reshape on @rs and adjust/initiate */
3836 	/* Be prepared for mddev_resume() in raid_resume() */
3837 	set_bit(MD_RECOVERY_FROZEN, &mddev->recovery);
3838 	if (mddev->recovery_cp && mddev->recovery_cp < MaxSector) {
3839 		set_bit(MD_RECOVERY_SYNC, &mddev->recovery);
3840 		mddev->resync_min = mddev->recovery_cp;
3841 	}
3842 
3843 	rs_set_capacity(rs);
3844 
3845 	/* Check for any reshape request unless new raid set */
3846 	if (test_and_clear_bit(RT_FLAG_RESHAPE_RS, &rs->runtime_flags)) {
3847 		/* Initiate a reshape. */
3848 		mddev_lock_nointr(mddev);
3849 		r = rs_start_reshape(rs);
3850 		mddev_unlock(mddev);
3851 		if (r)
3852 			DMWARN("Failed to check/start reshape, continuing without change");
3853 		r = 0;
3854 	}
3855 
3856 	return r;
3857 }
3858 
3859 static void raid_resume(struct dm_target *ti)
3860 {
3861 	struct raid_set *rs = ti->private;
3862 	struct mddev *mddev = &rs->md;
3863 
3864 	if (test_and_set_bit(RT_FLAG_RS_RESUMED, &rs->runtime_flags)) {
3865 		/*
3866 		 * A secondary resume while the device is active.
3867 		 * Take this opportunity to check whether any failed
3868 		 * devices are reachable again.
3869 		 */
3870 		attempt_restore_of_faulty_devices(rs);
3871 	}
3872 
3873 	mddev->ro = 0;
3874 	mddev->in_sync = 0;
3875 
3876 	/*
3877 	 * Keep the RAID set frozen if reshape/rebuild flags are set.
3878 	 * The RAID set is unfrozen once the next table load/resume,
3879 	 * which clears the reshape/rebuild flags, occurs.
3880 	 * This ensures that the constructor for the inactive table
3881 	 * retrieves an up-to-date reshape_position.
3882 	 */
3883 	if (!(rs->ctr_flags & RESUME_STAY_FROZEN_FLAGS))
3884 		clear_bit(MD_RECOVERY_FROZEN, &mddev->recovery);
3885 
3886 	if (mddev->suspended)
3887 		mddev_resume(mddev);
3888 }
3889 
3890 static struct target_type raid_target = {
3891 	.name = "raid",
3892 	.version = {1, 11, 1},
3893 	.module = THIS_MODULE,
3894 	.ctr = raid_ctr,
3895 	.dtr = raid_dtr,
3896 	.map = raid_map,
3897 	.status = raid_status,
3898 	.message = raid_message,
3899 	.iterate_devices = raid_iterate_devices,
3900 	.io_hints = raid_io_hints,
3901 	.presuspend = raid_presuspend,
3902 	.postsuspend = raid_postsuspend,
3903 	.preresume = raid_preresume,
3904 	.resume = raid_resume,
3905 };
3906 
3907 static int __init dm_raid_init(void)
3908 {
3909 	DMINFO("Loading target version %u.%u.%u",
3910 	       raid_target.version[0],
3911 	       raid_target.version[1],
3912 	       raid_target.version[2]);
3913 	return dm_register_target(&raid_target);
3914 }
3915 
3916 static void __exit dm_raid_exit(void)
3917 {
3918 	dm_unregister_target(&raid_target);
3919 }
3920 
3921 module_init(dm_raid_init);
3922 module_exit(dm_raid_exit);
3923 
3924 module_param(devices_handle_discard_safely, bool, 0644);
3925 MODULE_PARM_DESC(devices_handle_discard_safely,
3926 		 "Set to Y if all devices in each array reliably return zeroes on reads from discarded regions");
3927 
3928 MODULE_DESCRIPTION(DM_NAME " raid0/1/10/4/5/6 target");
3929 MODULE_ALIAS("dm-raid0");
3930 MODULE_ALIAS("dm-raid1");
3931 MODULE_ALIAS("dm-raid10");
3932 MODULE_ALIAS("dm-raid4");
3933 MODULE_ALIAS("dm-raid5");
3934 MODULE_ALIAS("dm-raid6");
3935 MODULE_AUTHOR("Neil Brown <dm-devel@redhat.com>");
3936 MODULE_AUTHOR("Heinz Mauelshagen <dm-devel@redhat.com>");
3937 MODULE_LICENSE("GPL");
3938