9a01d1e4c78302a0fef677e2c516f2bf3daeca70
[~shefty/rdma-dev.git] / drivers / md / dm-raid.c
1 /*
2  * Copyright (C) 2010-2011 Neil Brown
3  * Copyright (C) 2010-2011 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
21 /*
22  * The following flags are used by dm-raid.c to set up the array state.
23  * They must be cleared before md_run is called.
24  */
25 #define FirstUse 10             /* rdev flag */
26
27 struct raid_dev {
28         /*
29          * Two DM devices, one to hold metadata and one to hold the
30          * actual data/parity.  The reason for this is to not confuse
31          * ti->len and give more flexibility in altering size and
32          * characteristics.
33          *
34          * While it is possible for this device to be associated
35          * with a different physical device than the data_dev, it
36          * is intended for it to be the same.
37          *    |--------- Physical Device ---------|
38          *    |- meta_dev -|------ data_dev ------|
39          */
40         struct dm_dev *meta_dev;
41         struct dm_dev *data_dev;
42         struct md_rdev rdev;
43 };
44
45 /*
46  * Flags for rs->print_flags field.
47  */
48 #define DMPF_SYNC              0x1
49 #define DMPF_NOSYNC            0x2
50 #define DMPF_REBUILD           0x4
51 #define DMPF_DAEMON_SLEEP      0x8
52 #define DMPF_MIN_RECOVERY_RATE 0x10
53 #define DMPF_MAX_RECOVERY_RATE 0x20
54 #define DMPF_MAX_WRITE_BEHIND  0x40
55 #define DMPF_STRIPE_CACHE      0x80
56 #define DMPF_REGION_SIZE       0x100
57 #define DMPF_RAID10_COPIES     0x200
58 #define DMPF_RAID10_FORMAT     0x400
59
60 struct raid_set {
61         struct dm_target *ti;
62
63         uint32_t bitmap_loaded;
64         uint32_t print_flags;
65
66         struct mddev md;
67         struct raid_type *raid_type;
68         struct dm_target_callbacks callbacks;
69
70         struct raid_dev dev[0];
71 };
72
73 /* Supported raid types and properties. */
74 static struct raid_type {
75         const char *name;               /* RAID algorithm. */
76         const char *descr;              /* Descriptor text for logging. */
77         const unsigned parity_devs;     /* # of parity devices. */
78         const unsigned minimal_devs;    /* minimal # of devices in set. */
79         const unsigned level;           /* RAID level. */
80         const unsigned algorithm;       /* RAID algorithm. */
81 } raid_types[] = {
82         {"raid1",    "RAID1 (mirroring)",               0, 2, 1, 0 /* NONE */},
83         {"raid10",   "RAID10 (striped mirrors)",        0, 2, 10, UINT_MAX /* Varies */},
84         {"raid4",    "RAID4 (dedicated parity disk)",   1, 2, 5, ALGORITHM_PARITY_0},
85         {"raid5_la", "RAID5 (left asymmetric)",         1, 2, 5, ALGORITHM_LEFT_ASYMMETRIC},
86         {"raid5_ra", "RAID5 (right asymmetric)",        1, 2, 5, ALGORITHM_RIGHT_ASYMMETRIC},
87         {"raid5_ls", "RAID5 (left symmetric)",          1, 2, 5, ALGORITHM_LEFT_SYMMETRIC},
88         {"raid5_rs", "RAID5 (right symmetric)",         1, 2, 5, ALGORITHM_RIGHT_SYMMETRIC},
89         {"raid6_zr", "RAID6 (zero restart)",            2, 4, 6, ALGORITHM_ROTATING_ZERO_RESTART},
90         {"raid6_nr", "RAID6 (N restart)",               2, 4, 6, ALGORITHM_ROTATING_N_RESTART},
91         {"raid6_nc", "RAID6 (N continue)",              2, 4, 6, ALGORITHM_ROTATING_N_CONTINUE}
92 };
93
94 static unsigned raid10_md_layout_to_copies(int layout)
95 {
96         return layout & 0xFF;
97 }
98
99 static int raid10_format_to_md_layout(char *format, unsigned copies)
100 {
101         /* 1 "far" copy, and 'copies' "near" copies */
102         return (1 << 8) | (copies & 0xFF);
103 }
104
105 static struct raid_type *get_raid_type(char *name)
106 {
107         int i;
108
109         for (i = 0; i < ARRAY_SIZE(raid_types); i++)
110                 if (!strcmp(raid_types[i].name, name))
111                         return &raid_types[i];
112
113         return NULL;
114 }
115
116 static struct raid_set *context_alloc(struct dm_target *ti, struct raid_type *raid_type, unsigned raid_devs)
117 {
118         unsigned i;
119         struct raid_set *rs;
120
121         if (raid_devs <= raid_type->parity_devs) {
122                 ti->error = "Insufficient number of devices";
123                 return ERR_PTR(-EINVAL);
124         }
125
126         rs = kzalloc(sizeof(*rs) + raid_devs * sizeof(rs->dev[0]), GFP_KERNEL);
127         if (!rs) {
128                 ti->error = "Cannot allocate raid context";
129                 return ERR_PTR(-ENOMEM);
130         }
131
132         mddev_init(&rs->md);
133
134         rs->ti = ti;
135         rs->raid_type = raid_type;
136         rs->md.raid_disks = raid_devs;
137         rs->md.level = raid_type->level;
138         rs->md.new_level = rs->md.level;
139         rs->md.layout = raid_type->algorithm;
140         rs->md.new_layout = rs->md.layout;
141         rs->md.delta_disks = 0;
142         rs->md.recovery_cp = 0;
143
144         for (i = 0; i < raid_devs; i++)
145                 md_rdev_init(&rs->dev[i].rdev);
146
147         /*
148          * Remaining items to be initialized by further RAID params:
149          *  rs->md.persistent
150          *  rs->md.external
151          *  rs->md.chunk_sectors
152          *  rs->md.new_chunk_sectors
153          *  rs->md.dev_sectors
154          */
155
156         return rs;
157 }
158
159 static void context_free(struct raid_set *rs)
160 {
161         int i;
162
163         for (i = 0; i < rs->md.raid_disks; i++) {
164                 if (rs->dev[i].meta_dev)
165                         dm_put_device(rs->ti, rs->dev[i].meta_dev);
166                 md_rdev_clear(&rs->dev[i].rdev);
167                 if (rs->dev[i].data_dev)
168                         dm_put_device(rs->ti, rs->dev[i].data_dev);
169         }
170
171         kfree(rs);
172 }
173
174 /*
175  * For every device we have two words
176  *  <meta_dev>: meta device name or '-' if missing
177  *  <data_dev>: data device name or '-' if missing
178  *
179  * The following are permitted:
180  *    - -
181  *    - <data_dev>
182  *    <meta_dev> <data_dev>
183  *
184  * The following is not allowed:
185  *    <meta_dev> -
186  *
187  * This code parses those words.  If there is a failure,
188  * the caller must use context_free to unwind the operations.
189  */
190 static int dev_parms(struct raid_set *rs, char **argv)
191 {
192         int i;
193         int rebuild = 0;
194         int metadata_available = 0;
195         int ret = 0;
196
197         for (i = 0; i < rs->md.raid_disks; i++, argv += 2) {
198                 rs->dev[i].rdev.raid_disk = i;
199
200                 rs->dev[i].meta_dev = NULL;
201                 rs->dev[i].data_dev = NULL;
202
203                 /*
204                  * There are no offsets, since there is a separate device
205                  * for data and metadata.
206                  */
207                 rs->dev[i].rdev.data_offset = 0;
208                 rs->dev[i].rdev.mddev = &rs->md;
209
210                 if (strcmp(argv[0], "-")) {
211                         ret = dm_get_device(rs->ti, argv[0],
212                                             dm_table_get_mode(rs->ti->table),
213                                             &rs->dev[i].meta_dev);
214                         rs->ti->error = "RAID metadata device lookup failure";
215                         if (ret)
216                                 return ret;
217
218                         rs->dev[i].rdev.sb_page = alloc_page(GFP_KERNEL);
219                         if (!rs->dev[i].rdev.sb_page)
220                                 return -ENOMEM;
221                 }
222
223                 if (!strcmp(argv[1], "-")) {
224                         if (!test_bit(In_sync, &rs->dev[i].rdev.flags) &&
225                             (!rs->dev[i].rdev.recovery_offset)) {
226                                 rs->ti->error = "Drive designated for rebuild not specified";
227                                 return -EINVAL;
228                         }
229
230                         rs->ti->error = "No data device supplied with metadata device";
231                         if (rs->dev[i].meta_dev)
232                                 return -EINVAL;
233
234                         continue;
235                 }
236
237                 ret = dm_get_device(rs->ti, argv[1],
238                                     dm_table_get_mode(rs->ti->table),
239                                     &rs->dev[i].data_dev);
240                 if (ret) {
241                         rs->ti->error = "RAID device lookup failure";
242                         return ret;
243                 }
244
245                 if (rs->dev[i].meta_dev) {
246                         metadata_available = 1;
247                         rs->dev[i].rdev.meta_bdev = rs->dev[i].meta_dev->bdev;
248                 }
249                 rs->dev[i].rdev.bdev = rs->dev[i].data_dev->bdev;
250                 list_add(&rs->dev[i].rdev.same_set, &rs->md.disks);
251                 if (!test_bit(In_sync, &rs->dev[i].rdev.flags))
252                         rebuild++;
253         }
254
255         if (metadata_available) {
256                 rs->md.external = 0;
257                 rs->md.persistent = 1;
258                 rs->md.major_version = 2;
259         } else if (rebuild && !rs->md.recovery_cp) {
260                 /*
261                  * Without metadata, we will not be able to tell if the array
262                  * is in-sync or not - we must assume it is not.  Therefore,
263                  * it is impossible to rebuild a drive.
264                  *
265                  * Even if there is metadata, the on-disk information may
266                  * indicate that the array is not in-sync and it will then
267                  * fail at that time.
268                  *
269                  * User could specify 'nosync' option if desperate.
270                  */
271                 DMERR("Unable to rebuild drive while array is not in-sync");
272                 rs->ti->error = "RAID device lookup failure";
273                 return -EINVAL;
274         }
275
276         return 0;
277 }
278
279 /*
280  * validate_region_size
281  * @rs
282  * @region_size:  region size in sectors.  If 0, pick a size (4MiB default).
283  *
284  * Set rs->md.bitmap_info.chunksize (which really refers to 'region size').
285  * Ensure that (ti->len/region_size < 2^21) - required by MD bitmap.
286  *
287  * Returns: 0 on success, -EINVAL on failure.
288  */
289 static int validate_region_size(struct raid_set *rs, unsigned long region_size)
290 {
291         unsigned long min_region_size = rs->ti->len / (1 << 21);
292
293         if (!region_size) {
294                 /*
295                  * Choose a reasonable default.  All figures in sectors.
296                  */
297                 if (min_region_size > (1 << 13)) {
298                         /* If not a power of 2, make it the next power of 2 */
299                         if (min_region_size & (min_region_size - 1))
300                                 region_size = 1 << fls(region_size);
301                         DMINFO("Choosing default region size of %lu sectors",
302                                region_size);
303                 } else {
304                         DMINFO("Choosing default region size of 4MiB");
305                         region_size = 1 << 13; /* sectors */
306                 }
307         } else {
308                 /*
309                  * Validate user-supplied value.
310                  */
311                 if (region_size > rs->ti->len) {
312                         rs->ti->error = "Supplied region size is too large";
313                         return -EINVAL;
314                 }
315
316                 if (region_size < min_region_size) {
317                         DMERR("Supplied region_size (%lu sectors) below minimum (%lu)",
318                               region_size, min_region_size);
319                         rs->ti->error = "Supplied region size is too small";
320                         return -EINVAL;
321                 }
322
323                 if (!is_power_of_2(region_size)) {
324                         rs->ti->error = "Region size is not a power of 2";
325                         return -EINVAL;
326                 }
327
328                 if (region_size < rs->md.chunk_sectors) {
329                         rs->ti->error = "Region size is smaller than the chunk size";
330                         return -EINVAL;
331                 }
332         }
333
334         /*
335          * Convert sectors to bytes.
336          */
337         rs->md.bitmap_info.chunksize = (region_size << 9);
338
339         return 0;
340 }
341
342 /*
343  * validate_raid_redundancy
344  * @rs
345  *
346  * Determine if there are enough devices in the array that haven't
347  * failed (or are being rebuilt) to form a usable array.
348  *
349  * Returns: 0 on success, -EINVAL on failure.
350  */
351 static int validate_raid_redundancy(struct raid_set *rs)
352 {
353         unsigned i, rebuild_cnt = 0;
354         unsigned rebuilds_per_group, copies, d;
355
356         for (i = 0; i < rs->md.raid_disks; i++)
357                 if (!test_bit(In_sync, &rs->dev[i].rdev.flags) ||
358                     !rs->dev[i].rdev.sb_page)
359                         rebuild_cnt++;
360
361         switch (rs->raid_type->level) {
362         case 1:
363                 if (rebuild_cnt >= rs->md.raid_disks)
364                         goto too_many;
365                 break;
366         case 4:
367         case 5:
368         case 6:
369                 if (rebuild_cnt > rs->raid_type->parity_devs)
370                         goto too_many;
371                 break;
372         case 10:
373                 copies = raid10_md_layout_to_copies(rs->md.layout);
374                 if (rebuild_cnt < copies)
375                         break;
376
377                 /*
378                  * It is possible to have a higher rebuild count for RAID10,
379                  * as long as the failed devices occur in different mirror
380                  * groups (i.e. different stripes).
381                  *
382                  * Right now, we only allow for "near" copies.  When other
383                  * formats are added, we will have to check those too.
384                  *
385                  * When checking "near" format, make sure no adjacent devices
386                  * have failed beyond what can be handled.  In addition to the
387                  * simple case where the number of devices is a multiple of the
388                  * number of copies, we must also handle cases where the number
389                  * of devices is not a multiple of the number of copies.
390                  * E.g.    dev1 dev2 dev3 dev4 dev5
391                  *          A    A    B    B    C
392                  *          C    D    D    E    E
393                  */
394                 for (i = 0; i < rs->md.raid_disks * copies; i++) {
395                         if (!(i % copies))
396                                 rebuilds_per_group = 0;
397                         d = i % rs->md.raid_disks;
398                         if ((!rs->dev[d].rdev.sb_page ||
399                              !test_bit(In_sync, &rs->dev[d].rdev.flags)) &&
400                             (++rebuilds_per_group >= copies))
401                                 goto too_many;
402                 }
403                 break;
404         default:
405                 if (rebuild_cnt)
406                         return -EINVAL;
407         }
408
409         return 0;
410
411 too_many:
412         return -EINVAL;
413 }
414
415 /*
416  * Possible arguments are...
417  *      <chunk_size> [optional_args]
418  *
419  * Argument definitions
420  *    <chunk_size>                      The number of sectors per disk that
421  *                                      will form the "stripe"
422  *    [[no]sync]                        Force or prevent recovery of the
423  *                                      entire array
424  *    [rebuild <idx>]                   Rebuild the drive indicated by the index
425  *    [daemon_sleep <ms>]               Time between bitmap daemon work to
426  *                                      clear bits
427  *    [min_recovery_rate <kB/sec/disk>] Throttle RAID initialization
428  *    [max_recovery_rate <kB/sec/disk>] Throttle RAID initialization
429  *    [write_mostly <idx>]              Indicate a write mostly drive via index
430  *    [max_write_behind <sectors>]      See '-write-behind=' (man mdadm)
431  *    [stripe_cache <sectors>]          Stripe cache size for higher RAIDs
432  *    [region_size <sectors>]           Defines granularity of bitmap
433  *
434  * RAID10-only options:
435  *    [raid10_copies <# copies>]        Number of copies.  (Default: 2)
436  *    [raid10_format <near>]            Layout algorithm.  (Default: near)
437  */
438 static int parse_raid_params(struct raid_set *rs, char **argv,
439                              unsigned num_raid_params)
440 {
441         char *raid10_format = "near";
442         unsigned raid10_copies = 2;
443         unsigned i;
444         unsigned long value, region_size = 0;
445         sector_t sectors_per_dev = rs->ti->len;
446         sector_t max_io_len;
447         char *key;
448
449         /*
450          * First, parse the in-order required arguments
451          * "chunk_size" is the only argument of this type.
452          */
453         if ((strict_strtoul(argv[0], 10, &value) < 0)) {
454                 rs->ti->error = "Bad chunk size";
455                 return -EINVAL;
456         } else if (rs->raid_type->level == 1) {
457                 if (value)
458                         DMERR("Ignoring chunk size parameter for RAID 1");
459                 value = 0;
460         } else if (!is_power_of_2(value)) {
461                 rs->ti->error = "Chunk size must be a power of 2";
462                 return -EINVAL;
463         } else if (value < 8) {
464                 rs->ti->error = "Chunk size value is too small";
465                 return -EINVAL;
466         }
467
468         rs->md.new_chunk_sectors = rs->md.chunk_sectors = value;
469         argv++;
470         num_raid_params--;
471
472         /*
473          * We set each individual device as In_sync with a completed
474          * 'recovery_offset'.  If there has been a device failure or
475          * replacement then one of the following cases applies:
476          *
477          *   1) User specifies 'rebuild'.
478          *      - Device is reset when param is read.
479          *   2) A new device is supplied.
480          *      - No matching superblock found, resets device.
481          *   3) Device failure was transient and returns on reload.
482          *      - Failure noticed, resets device for bitmap replay.
483          *   4) Device hadn't completed recovery after previous failure.
484          *      - Superblock is read and overrides recovery_offset.
485          *
486          * What is found in the superblocks of the devices is always
487          * authoritative, unless 'rebuild' or '[no]sync' was specified.
488          */
489         for (i = 0; i < rs->md.raid_disks; i++) {
490                 set_bit(In_sync, &rs->dev[i].rdev.flags);
491                 rs->dev[i].rdev.recovery_offset = MaxSector;
492         }
493
494         /*
495          * Second, parse the unordered optional arguments
496          */
497         for (i = 0; i < num_raid_params; i++) {
498                 if (!strcasecmp(argv[i], "nosync")) {
499                         rs->md.recovery_cp = MaxSector;
500                         rs->print_flags |= DMPF_NOSYNC;
501                         continue;
502                 }
503                 if (!strcasecmp(argv[i], "sync")) {
504                         rs->md.recovery_cp = 0;
505                         rs->print_flags |= DMPF_SYNC;
506                         continue;
507                 }
508
509                 /* The rest of the optional arguments come in key/value pairs */
510                 if ((i + 1) >= num_raid_params) {
511                         rs->ti->error = "Wrong number of raid parameters given";
512                         return -EINVAL;
513                 }
514
515                 key = argv[i++];
516
517                 /* Parameters that take a string value are checked here. */
518                 if (!strcasecmp(key, "raid10_format")) {
519                         if (rs->raid_type->level != 10) {
520                                 rs->ti->error = "'raid10_format' is an invalid parameter for this RAID type";
521                                 return -EINVAL;
522                         }
523                         if (strcmp("near", argv[i])) {
524                                 rs->ti->error = "Invalid 'raid10_format' value given";
525                                 return -EINVAL;
526                         }
527                         raid10_format = argv[i];
528                         rs->print_flags |= DMPF_RAID10_FORMAT;
529                         continue;
530                 }
531
532                 if (strict_strtoul(argv[i], 10, &value) < 0) {
533                         rs->ti->error = "Bad numerical argument given in raid params";
534                         return -EINVAL;
535                 }
536
537                 /* Parameters that take a numeric value are checked here */
538                 if (!strcasecmp(key, "rebuild")) {
539                         if (value >= rs->md.raid_disks) {
540                                 rs->ti->error = "Invalid rebuild index given";
541                                 return -EINVAL;
542                         }
543                         clear_bit(In_sync, &rs->dev[value].rdev.flags);
544                         rs->dev[value].rdev.recovery_offset = 0;
545                         rs->print_flags |= DMPF_REBUILD;
546                 } else if (!strcasecmp(key, "write_mostly")) {
547                         if (rs->raid_type->level != 1) {
548                                 rs->ti->error = "write_mostly option is only valid for RAID1";
549                                 return -EINVAL;
550                         }
551                         if (value >= rs->md.raid_disks) {
552                                 rs->ti->error = "Invalid write_mostly drive index given";
553                                 return -EINVAL;
554                         }
555                         set_bit(WriteMostly, &rs->dev[value].rdev.flags);
556                 } else if (!strcasecmp(key, "max_write_behind")) {
557                         if (rs->raid_type->level != 1) {
558                                 rs->ti->error = "max_write_behind option is only valid for RAID1";
559                                 return -EINVAL;
560                         }
561                         rs->print_flags |= DMPF_MAX_WRITE_BEHIND;
562
563                         /*
564                          * In device-mapper, we specify things in sectors, but
565                          * MD records this value in kB
566                          */
567                         value /= 2;
568                         if (value > COUNTER_MAX) {
569                                 rs->ti->error = "Max write-behind limit out of range";
570                                 return -EINVAL;
571                         }
572                         rs->md.bitmap_info.max_write_behind = value;
573                 } else if (!strcasecmp(key, "daemon_sleep")) {
574                         rs->print_flags |= DMPF_DAEMON_SLEEP;
575                         if (!value || (value > MAX_SCHEDULE_TIMEOUT)) {
576                                 rs->ti->error = "daemon sleep period out of range";
577                                 return -EINVAL;
578                         }
579                         rs->md.bitmap_info.daemon_sleep = value;
580                 } else if (!strcasecmp(key, "stripe_cache")) {
581                         rs->print_flags |= DMPF_STRIPE_CACHE;
582
583                         /*
584                          * In device-mapper, we specify things in sectors, but
585                          * MD records this value in kB
586                          */
587                         value /= 2;
588
589                         if ((rs->raid_type->level != 5) &&
590                             (rs->raid_type->level != 6)) {
591                                 rs->ti->error = "Inappropriate argument: stripe_cache";
592                                 return -EINVAL;
593                         }
594                         if (raid5_set_cache_size(&rs->md, (int)value)) {
595                                 rs->ti->error = "Bad stripe_cache size";
596                                 return -EINVAL;
597                         }
598                 } else if (!strcasecmp(key, "min_recovery_rate")) {
599                         rs->print_flags |= DMPF_MIN_RECOVERY_RATE;
600                         if (value > INT_MAX) {
601                                 rs->ti->error = "min_recovery_rate out of range";
602                                 return -EINVAL;
603                         }
604                         rs->md.sync_speed_min = (int)value;
605                 } else if (!strcasecmp(key, "max_recovery_rate")) {
606                         rs->print_flags |= DMPF_MAX_RECOVERY_RATE;
607                         if (value > INT_MAX) {
608                                 rs->ti->error = "max_recovery_rate out of range";
609                                 return -EINVAL;
610                         }
611                         rs->md.sync_speed_max = (int)value;
612                 } else if (!strcasecmp(key, "region_size")) {
613                         rs->print_flags |= DMPF_REGION_SIZE;
614                         region_size = value;
615                 } else if (!strcasecmp(key, "raid10_copies") &&
616                            (rs->raid_type->level == 10)) {
617                         if ((value < 2) || (value > 0xFF)) {
618                                 rs->ti->error = "Bad value for 'raid10_copies'";
619                                 return -EINVAL;
620                         }
621                         rs->print_flags |= DMPF_RAID10_COPIES;
622                         raid10_copies = value;
623                 } else {
624                         DMERR("Unable to parse RAID parameter: %s", key);
625                         rs->ti->error = "Unable to parse RAID parameters";
626                         return -EINVAL;
627                 }
628         }
629
630         if (validate_region_size(rs, region_size))
631                 return -EINVAL;
632
633         if (rs->md.chunk_sectors)
634                 max_io_len = rs->md.chunk_sectors;
635         else
636                 max_io_len = region_size;
637
638         if (dm_set_target_max_io_len(rs->ti, max_io_len))
639                 return -EINVAL;
640
641         if (rs->raid_type->level == 10) {
642                 if (raid10_copies > rs->md.raid_disks) {
643                         rs->ti->error = "Not enough devices to satisfy specification";
644                         return -EINVAL;
645                 }
646
647                 /* (Len * #mirrors) / #devices */
648                 sectors_per_dev = rs->ti->len * raid10_copies;
649                 sector_div(sectors_per_dev, rs->md.raid_disks);
650
651                 rs->md.layout = raid10_format_to_md_layout(raid10_format,
652                                                            raid10_copies);
653                 rs->md.new_layout = rs->md.layout;
654         } else if ((rs->raid_type->level > 1) &&
655                    sector_div(sectors_per_dev,
656                               (rs->md.raid_disks - rs->raid_type->parity_devs))) {
657                 rs->ti->error = "Target length not divisible by number of data devices";
658                 return -EINVAL;
659         }
660         rs->md.dev_sectors = sectors_per_dev;
661
662         /* Assume there are no metadata devices until the drives are parsed */
663         rs->md.persistent = 0;
664         rs->md.external = 1;
665
666         return 0;
667 }
668
669 static void do_table_event(struct work_struct *ws)
670 {
671         struct raid_set *rs = container_of(ws, struct raid_set, md.event_work);
672
673         dm_table_event(rs->ti->table);
674 }
675
676 static int raid_is_congested(struct dm_target_callbacks *cb, int bits)
677 {
678         struct raid_set *rs = container_of(cb, struct raid_set, callbacks);
679
680         if (rs->raid_type->level == 1)
681                 return md_raid1_congested(&rs->md, bits);
682
683         if (rs->raid_type->level == 10)
684                 return md_raid10_congested(&rs->md, bits);
685
686         return md_raid5_congested(&rs->md, bits);
687 }
688
689 /*
690  * This structure is never routinely used by userspace, unlike md superblocks.
691  * Devices with this superblock should only ever be accessed via device-mapper.
692  */
693 #define DM_RAID_MAGIC 0x64526D44
694 struct dm_raid_superblock {
695         __le32 magic;           /* "DmRd" */
696         __le32 features;        /* Used to indicate possible future changes */
697
698         __le32 num_devices;     /* Number of devices in this array. (Max 64) */
699         __le32 array_position;  /* The position of this drive in the array */
700
701         __le64 events;          /* Incremented by md when superblock updated */
702         __le64 failed_devices;  /* Bit field of devices to indicate failures */
703
704         /*
705          * This offset tracks the progress of the repair or replacement of
706          * an individual drive.
707          */
708         __le64 disk_recovery_offset;
709
710         /*
711          * This offset tracks the progress of the initial array
712          * synchronisation/parity calculation.
713          */
714         __le64 array_resync_offset;
715
716         /*
717          * RAID characteristics
718          */
719         __le32 level;
720         __le32 layout;
721         __le32 stripe_sectors;
722
723         __u8 pad[452];          /* Round struct to 512 bytes. */
724                                 /* Always set to 0 when writing. */
725 } __packed;
726
727 static int read_disk_sb(struct md_rdev *rdev, int size)
728 {
729         BUG_ON(!rdev->sb_page);
730
731         if (rdev->sb_loaded)
732                 return 0;
733
734         if (!sync_page_io(rdev, 0, size, rdev->sb_page, READ, 1)) {
735                 DMERR("Failed to read superblock of device at position %d",
736                       rdev->raid_disk);
737                 md_error(rdev->mddev, rdev);
738                 return -EINVAL;
739         }
740
741         rdev->sb_loaded = 1;
742
743         return 0;
744 }
745
746 static void super_sync(struct mddev *mddev, struct md_rdev *rdev)
747 {
748         int i;
749         uint64_t failed_devices;
750         struct dm_raid_superblock *sb;
751         struct raid_set *rs = container_of(mddev, struct raid_set, md);
752
753         sb = page_address(rdev->sb_page);
754         failed_devices = le64_to_cpu(sb->failed_devices);
755
756         for (i = 0; i < mddev->raid_disks; i++)
757                 if (!rs->dev[i].data_dev ||
758                     test_bit(Faulty, &(rs->dev[i].rdev.flags)))
759                         failed_devices |= (1ULL << i);
760
761         memset(sb, 0, sizeof(*sb));
762
763         sb->magic = cpu_to_le32(DM_RAID_MAGIC);
764         sb->features = cpu_to_le32(0);  /* No features yet */
765
766         sb->num_devices = cpu_to_le32(mddev->raid_disks);
767         sb->array_position = cpu_to_le32(rdev->raid_disk);
768
769         sb->events = cpu_to_le64(mddev->events);
770         sb->failed_devices = cpu_to_le64(failed_devices);
771
772         sb->disk_recovery_offset = cpu_to_le64(rdev->recovery_offset);
773         sb->array_resync_offset = cpu_to_le64(mddev->recovery_cp);
774
775         sb->level = cpu_to_le32(mddev->level);
776         sb->layout = cpu_to_le32(mddev->layout);
777         sb->stripe_sectors = cpu_to_le32(mddev->chunk_sectors);
778 }
779
780 /*
781  * super_load
782  *
783  * This function creates a superblock if one is not found on the device
784  * and will decide which superblock to use if there's a choice.
785  *
786  * Return: 1 if use rdev, 0 if use refdev, -Exxx otherwise
787  */
788 static int super_load(struct md_rdev *rdev, struct md_rdev *refdev)
789 {
790         int ret;
791         struct dm_raid_superblock *sb;
792         struct dm_raid_superblock *refsb;
793         uint64_t events_sb, events_refsb;
794
795         rdev->sb_start = 0;
796         rdev->sb_size = sizeof(*sb);
797
798         ret = read_disk_sb(rdev, rdev->sb_size);
799         if (ret)
800                 return ret;
801
802         sb = page_address(rdev->sb_page);
803
804         /*
805          * Two cases that we want to write new superblocks and rebuild:
806          * 1) New device (no matching magic number)
807          * 2) Device specified for rebuild (!In_sync w/ offset == 0)
808          */
809         if ((sb->magic != cpu_to_le32(DM_RAID_MAGIC)) ||
810             (!test_bit(In_sync, &rdev->flags) && !rdev->recovery_offset)) {
811                 super_sync(rdev->mddev, rdev);
812
813                 set_bit(FirstUse, &rdev->flags);
814
815                 /* Force writing of superblocks to disk */
816                 set_bit(MD_CHANGE_DEVS, &rdev->mddev->flags);
817
818                 /* Any superblock is better than none, choose that if given */
819                 return refdev ? 0 : 1;
820         }
821
822         if (!refdev)
823                 return 1;
824
825         events_sb = le64_to_cpu(sb->events);
826
827         refsb = page_address(refdev->sb_page);
828         events_refsb = le64_to_cpu(refsb->events);
829
830         return (events_sb > events_refsb) ? 1 : 0;
831 }
832
833 static int super_init_validation(struct mddev *mddev, struct md_rdev *rdev)
834 {
835         int role;
836         struct raid_set *rs = container_of(mddev, struct raid_set, md);
837         uint64_t events_sb;
838         uint64_t failed_devices;
839         struct dm_raid_superblock *sb;
840         uint32_t new_devs = 0;
841         uint32_t rebuilds = 0;
842         struct md_rdev *r;
843         struct dm_raid_superblock *sb2;
844
845         sb = page_address(rdev->sb_page);
846         events_sb = le64_to_cpu(sb->events);
847         failed_devices = le64_to_cpu(sb->failed_devices);
848
849         /*
850          * Initialise to 1 if this is a new superblock.
851          */
852         mddev->events = events_sb ? : 1;
853
854         /*
855          * Reshaping is not currently allowed
856          */
857         if ((le32_to_cpu(sb->level) != mddev->level) ||
858             (le32_to_cpu(sb->layout) != mddev->layout) ||
859             (le32_to_cpu(sb->stripe_sectors) != mddev->chunk_sectors)) {
860                 DMERR("Reshaping arrays not yet supported.");
861                 return -EINVAL;
862         }
863
864         /* We can only change the number of devices in RAID1 right now */
865         if ((rs->raid_type->level != 1) &&
866             (le32_to_cpu(sb->num_devices) != mddev->raid_disks)) {
867                 DMERR("Reshaping arrays not yet supported.");
868                 return -EINVAL;
869         }
870
871         if (!(rs->print_flags & (DMPF_SYNC | DMPF_NOSYNC)))
872                 mddev->recovery_cp = le64_to_cpu(sb->array_resync_offset);
873
874         /*
875          * During load, we set FirstUse if a new superblock was written.
876          * There are two reasons we might not have a superblock:
877          * 1) The array is brand new - in which case, all of the
878          *    devices must have their In_sync bit set.  Also,
879          *    recovery_cp must be 0, unless forced.
880          * 2) This is a new device being added to an old array
881          *    and the new device needs to be rebuilt - in which
882          *    case the In_sync bit will /not/ be set and
883          *    recovery_cp must be MaxSector.
884          */
885         rdev_for_each(r, mddev) {
886                 if (!test_bit(In_sync, &r->flags)) {
887                         DMINFO("Device %d specified for rebuild: "
888                                "Clearing superblock", r->raid_disk);
889                         rebuilds++;
890                 } else if (test_bit(FirstUse, &r->flags))
891                         new_devs++;
892         }
893
894         if (!rebuilds) {
895                 if (new_devs == mddev->raid_disks) {
896                         DMINFO("Superblocks created for new array");
897                         set_bit(MD_ARRAY_FIRST_USE, &mddev->flags);
898                 } else if (new_devs) {
899                         DMERR("New device injected "
900                               "into existing array without 'rebuild' "
901                               "parameter specified");
902                         return -EINVAL;
903                 }
904         } else if (new_devs) {
905                 DMERR("'rebuild' devices cannot be "
906                       "injected into an array with other first-time devices");
907                 return -EINVAL;
908         } else if (mddev->recovery_cp != MaxSector) {
909                 DMERR("'rebuild' specified while array is not in-sync");
910                 return -EINVAL;
911         }
912
913         /*
914          * Now we set the Faulty bit for those devices that are
915          * recorded in the superblock as failed.
916          */
917         rdev_for_each(r, mddev) {
918                 if (!r->sb_page)
919                         continue;
920                 sb2 = page_address(r->sb_page);
921                 sb2->failed_devices = 0;
922
923                 /*
924                  * Check for any device re-ordering.
925                  */
926                 if (!test_bit(FirstUse, &r->flags) && (r->raid_disk >= 0)) {
927                         role = le32_to_cpu(sb2->array_position);
928                         if (role != r->raid_disk) {
929                                 if (rs->raid_type->level != 1) {
930                                         rs->ti->error = "Cannot change device "
931                                                 "positions in RAID array";
932                                         return -EINVAL;
933                                 }
934                                 DMINFO("RAID1 device #%d now at position #%d",
935                                        role, r->raid_disk);
936                         }
937
938                         /*
939                          * Partial recovery is performed on
940                          * returning failed devices.
941                          */
942                         if (failed_devices & (1 << role))
943                                 set_bit(Faulty, &r->flags);
944                 }
945         }
946
947         return 0;
948 }
949
950 static int super_validate(struct mddev *mddev, struct md_rdev *rdev)
951 {
952         struct dm_raid_superblock *sb = page_address(rdev->sb_page);
953
954         /*
955          * If mddev->events is not set, we know we have not yet initialized
956          * the array.
957          */
958         if (!mddev->events && super_init_validation(mddev, rdev))
959                 return -EINVAL;
960
961         mddev->bitmap_info.offset = 4096 >> 9; /* Enable bitmap creation */
962         rdev->mddev->bitmap_info.default_offset = 4096 >> 9;
963         if (!test_bit(FirstUse, &rdev->flags)) {
964                 rdev->recovery_offset = le64_to_cpu(sb->disk_recovery_offset);
965                 if (rdev->recovery_offset != MaxSector)
966                         clear_bit(In_sync, &rdev->flags);
967         }
968
969         /*
970          * If a device comes back, set it as not In_sync and no longer faulty.
971          */
972         if (test_bit(Faulty, &rdev->flags)) {
973                 clear_bit(Faulty, &rdev->flags);
974                 clear_bit(In_sync, &rdev->flags);
975                 rdev->saved_raid_disk = rdev->raid_disk;
976                 rdev->recovery_offset = 0;
977         }
978
979         clear_bit(FirstUse, &rdev->flags);
980
981         return 0;
982 }
983
984 /*
985  * Analyse superblocks and select the freshest.
986  */
987 static int analyse_superblocks(struct dm_target *ti, struct raid_set *rs)
988 {
989         int ret;
990         struct raid_dev *dev;
991         struct md_rdev *rdev, *tmp, *freshest;
992         struct mddev *mddev = &rs->md;
993
994         freshest = NULL;
995         rdev_for_each_safe(rdev, tmp, mddev) {
996                 /*
997                  * Skipping super_load due to DMPF_SYNC will cause
998                  * the array to undergo initialization again as
999                  * though it were new.  This is the intended effect
1000                  * of the "sync" directive.
1001                  *
1002                  * When reshaping capability is added, we must ensure
1003                  * that the "sync" directive is disallowed during the
1004                  * reshape.
1005                  */
1006                 if (rs->print_flags & DMPF_SYNC)
1007                         continue;
1008
1009                 if (!rdev->meta_bdev)
1010                         continue;
1011
1012                 ret = super_load(rdev, freshest);
1013
1014                 switch (ret) {
1015                 case 1:
1016                         freshest = rdev;
1017                         break;
1018                 case 0:
1019                         break;
1020                 default:
1021                         dev = container_of(rdev, struct raid_dev, rdev);
1022                         if (dev->meta_dev)
1023                                 dm_put_device(ti, dev->meta_dev);
1024
1025                         dev->meta_dev = NULL;
1026                         rdev->meta_bdev = NULL;
1027
1028                         if (rdev->sb_page)
1029                                 put_page(rdev->sb_page);
1030
1031                         rdev->sb_page = NULL;
1032
1033                         rdev->sb_loaded = 0;
1034
1035                         /*
1036                          * We might be able to salvage the data device
1037                          * even though the meta device has failed.  For
1038                          * now, we behave as though '- -' had been
1039                          * set for this device in the table.
1040                          */
1041                         if (dev->data_dev)
1042                                 dm_put_device(ti, dev->data_dev);
1043
1044                         dev->data_dev = NULL;
1045                         rdev->bdev = NULL;
1046
1047                         list_del(&rdev->same_set);
1048                 }
1049         }
1050
1051         if (!freshest)
1052                 return 0;
1053
1054         if (validate_raid_redundancy(rs)) {
1055                 rs->ti->error = "Insufficient redundancy to activate array";
1056                 return -EINVAL;
1057         }
1058
1059         /*
1060          * Validation of the freshest device provides the source of
1061          * validation for the remaining devices.
1062          */
1063         ti->error = "Unable to assemble array: Invalid superblocks";
1064         if (super_validate(mddev, freshest))
1065                 return -EINVAL;
1066
1067         rdev_for_each(rdev, mddev)
1068                 if ((rdev != freshest) && super_validate(mddev, rdev))
1069                         return -EINVAL;
1070
1071         return 0;
1072 }
1073
1074 /*
1075  * Construct a RAID4/5/6 mapping:
1076  * Args:
1077  *      <raid_type> <#raid_params> <raid_params>                \
1078  *      <#raid_devs> { <meta_dev1> <dev1> .. <meta_devN> <devN> }
1079  *
1080  * <raid_params> varies by <raid_type>.  See 'parse_raid_params' for
1081  * details on possible <raid_params>.
1082  */
1083 static int raid_ctr(struct dm_target *ti, unsigned argc, char **argv)
1084 {
1085         int ret;
1086         struct raid_type *rt;
1087         unsigned long num_raid_params, num_raid_devs;
1088         struct raid_set *rs = NULL;
1089
1090         /* Must have at least <raid_type> <#raid_params> */
1091         if (argc < 2) {
1092                 ti->error = "Too few arguments";
1093                 return -EINVAL;
1094         }
1095
1096         /* raid type */
1097         rt = get_raid_type(argv[0]);
1098         if (!rt) {
1099                 ti->error = "Unrecognised raid_type";
1100                 return -EINVAL;
1101         }
1102         argc--;
1103         argv++;
1104
1105         /* number of RAID parameters */
1106         if (strict_strtoul(argv[0], 10, &num_raid_params) < 0) {
1107                 ti->error = "Cannot understand number of RAID parameters";
1108                 return -EINVAL;
1109         }
1110         argc--;
1111         argv++;
1112
1113         /* Skip over RAID params for now and find out # of devices */
1114         if (num_raid_params + 1 > argc) {
1115                 ti->error = "Arguments do not agree with counts given";
1116                 return -EINVAL;
1117         }
1118
1119         if ((strict_strtoul(argv[num_raid_params], 10, &num_raid_devs) < 0) ||
1120             (num_raid_devs >= INT_MAX)) {
1121                 ti->error = "Cannot understand number of raid devices";
1122                 return -EINVAL;
1123         }
1124
1125         rs = context_alloc(ti, rt, (unsigned)num_raid_devs);
1126         if (IS_ERR(rs))
1127                 return PTR_ERR(rs);
1128
1129         ret = parse_raid_params(rs, argv, (unsigned)num_raid_params);
1130         if (ret)
1131                 goto bad;
1132
1133         ret = -EINVAL;
1134
1135         argc -= num_raid_params + 1; /* +1: we already have num_raid_devs */
1136         argv += num_raid_params + 1;
1137
1138         if (argc != (num_raid_devs * 2)) {
1139                 ti->error = "Supplied RAID devices does not match the count given";
1140                 goto bad;
1141         }
1142
1143         ret = dev_parms(rs, argv);
1144         if (ret)
1145                 goto bad;
1146
1147         rs->md.sync_super = super_sync;
1148         ret = analyse_superblocks(ti, rs);
1149         if (ret)
1150                 goto bad;
1151
1152         INIT_WORK(&rs->md.event_work, do_table_event);
1153         ti->private = rs;
1154         ti->num_flush_bios = 1;
1155
1156         mutex_lock(&rs->md.reconfig_mutex);
1157         ret = md_run(&rs->md);
1158         rs->md.in_sync = 0; /* Assume already marked dirty */
1159         mutex_unlock(&rs->md.reconfig_mutex);
1160
1161         if (ret) {
1162                 ti->error = "Fail to run raid array";
1163                 goto bad;
1164         }
1165
1166         if (ti->len != rs->md.array_sectors) {
1167                 ti->error = "Array size does not match requested target length";
1168                 ret = -EINVAL;
1169                 goto size_mismatch;
1170         }
1171         rs->callbacks.congested_fn = raid_is_congested;
1172         dm_table_add_target_callbacks(ti->table, &rs->callbacks);
1173
1174         mddev_suspend(&rs->md);
1175         return 0;
1176
1177 size_mismatch:
1178         md_stop(&rs->md);
1179 bad:
1180         context_free(rs);
1181
1182         return ret;
1183 }
1184
1185 static void raid_dtr(struct dm_target *ti)
1186 {
1187         struct raid_set *rs = ti->private;
1188
1189         list_del_init(&rs->callbacks.list);
1190         md_stop(&rs->md);
1191         context_free(rs);
1192 }
1193
1194 static int raid_map(struct dm_target *ti, struct bio *bio)
1195 {
1196         struct raid_set *rs = ti->private;
1197         struct mddev *mddev = &rs->md;
1198
1199         mddev->pers->make_request(mddev, bio);
1200
1201         return DM_MAPIO_SUBMITTED;
1202 }
1203
1204 static void raid_status(struct dm_target *ti, status_type_t type,
1205                         unsigned status_flags, char *result, unsigned maxlen)
1206 {
1207         struct raid_set *rs = ti->private;
1208         unsigned raid_param_cnt = 1; /* at least 1 for chunksize */
1209         unsigned sz = 0;
1210         int i, array_in_sync = 0;
1211         sector_t sync;
1212
1213         switch (type) {
1214         case STATUSTYPE_INFO:
1215                 DMEMIT("%s %d ", rs->raid_type->name, rs->md.raid_disks);
1216
1217                 if (test_bit(MD_RECOVERY_RUNNING, &rs->md.recovery))
1218                         sync = rs->md.curr_resync_completed;
1219                 else
1220                         sync = rs->md.recovery_cp;
1221
1222                 if (sync >= rs->md.resync_max_sectors) {
1223                         array_in_sync = 1;
1224                         sync = rs->md.resync_max_sectors;
1225                 } else {
1226                         /*
1227                          * The array may be doing an initial sync, or it may
1228                          * be rebuilding individual components.  If all the
1229                          * devices are In_sync, then it is the array that is
1230                          * being initialized.
1231                          */
1232                         for (i = 0; i < rs->md.raid_disks; i++)
1233                                 if (!test_bit(In_sync, &rs->dev[i].rdev.flags))
1234                                         array_in_sync = 1;
1235                 }
1236                 /*
1237                  * Status characters:
1238                  *  'D' = Dead/Failed device
1239                  *  'a' = Alive but not in-sync
1240                  *  'A' = Alive and in-sync
1241                  */
1242                 for (i = 0; i < rs->md.raid_disks; i++) {
1243                         if (test_bit(Faulty, &rs->dev[i].rdev.flags))
1244                                 DMEMIT("D");
1245                         else if (!array_in_sync ||
1246                                  !test_bit(In_sync, &rs->dev[i].rdev.flags))
1247                                 DMEMIT("a");
1248                         else
1249                                 DMEMIT("A");
1250                 }
1251
1252                 /*
1253                  * In-sync ratio:
1254                  *  The in-sync ratio shows the progress of:
1255                  *   - Initializing the array
1256                  *   - Rebuilding a subset of devices of the array
1257                  *  The user can distinguish between the two by referring
1258                  *  to the status characters.
1259                  */
1260                 DMEMIT(" %llu/%llu",
1261                        (unsigned long long) sync,
1262                        (unsigned long long) rs->md.resync_max_sectors);
1263
1264                 break;
1265         case STATUSTYPE_TABLE:
1266                 /* The string you would use to construct this array */
1267                 for (i = 0; i < rs->md.raid_disks; i++) {
1268                         if ((rs->print_flags & DMPF_REBUILD) &&
1269                             rs->dev[i].data_dev &&
1270                             !test_bit(In_sync, &rs->dev[i].rdev.flags))
1271                                 raid_param_cnt += 2; /* for rebuilds */
1272                         if (rs->dev[i].data_dev &&
1273                             test_bit(WriteMostly, &rs->dev[i].rdev.flags))
1274                                 raid_param_cnt += 2;
1275                 }
1276
1277                 raid_param_cnt += (hweight32(rs->print_flags & ~DMPF_REBUILD) * 2);
1278                 if (rs->print_flags & (DMPF_SYNC | DMPF_NOSYNC))
1279                         raid_param_cnt--;
1280
1281                 DMEMIT("%s %u %u", rs->raid_type->name,
1282                        raid_param_cnt, rs->md.chunk_sectors);
1283
1284                 if ((rs->print_flags & DMPF_SYNC) &&
1285                     (rs->md.recovery_cp == MaxSector))
1286                         DMEMIT(" sync");
1287                 if (rs->print_flags & DMPF_NOSYNC)
1288                         DMEMIT(" nosync");
1289
1290                 for (i = 0; i < rs->md.raid_disks; i++)
1291                         if ((rs->print_flags & DMPF_REBUILD) &&
1292                             rs->dev[i].data_dev &&
1293                             !test_bit(In_sync, &rs->dev[i].rdev.flags))
1294                                 DMEMIT(" rebuild %u", i);
1295
1296                 if (rs->print_flags & DMPF_DAEMON_SLEEP)
1297                         DMEMIT(" daemon_sleep %lu",
1298                                rs->md.bitmap_info.daemon_sleep);
1299
1300                 if (rs->print_flags & DMPF_MIN_RECOVERY_RATE)
1301                         DMEMIT(" min_recovery_rate %d", rs->md.sync_speed_min);
1302
1303                 if (rs->print_flags & DMPF_MAX_RECOVERY_RATE)
1304                         DMEMIT(" max_recovery_rate %d", rs->md.sync_speed_max);
1305
1306                 for (i = 0; i < rs->md.raid_disks; i++)
1307                         if (rs->dev[i].data_dev &&
1308                             test_bit(WriteMostly, &rs->dev[i].rdev.flags))
1309                                 DMEMIT(" write_mostly %u", i);
1310
1311                 if (rs->print_flags & DMPF_MAX_WRITE_BEHIND)
1312                         DMEMIT(" max_write_behind %lu",
1313                                rs->md.bitmap_info.max_write_behind);
1314
1315                 if (rs->print_flags & DMPF_STRIPE_CACHE) {
1316                         struct r5conf *conf = rs->md.private;
1317
1318                         /* convert from kiB to sectors */
1319                         DMEMIT(" stripe_cache %d",
1320                                conf ? conf->max_nr_stripes * 2 : 0);
1321                 }
1322
1323                 if (rs->print_flags & DMPF_REGION_SIZE)
1324                         DMEMIT(" region_size %lu",
1325                                rs->md.bitmap_info.chunksize >> 9);
1326
1327                 if (rs->print_flags & DMPF_RAID10_COPIES)
1328                         DMEMIT(" raid10_copies %u",
1329                                raid10_md_layout_to_copies(rs->md.layout));
1330
1331                 if (rs->print_flags & DMPF_RAID10_FORMAT)
1332                         DMEMIT(" raid10_format near");
1333
1334                 DMEMIT(" %d", rs->md.raid_disks);
1335                 for (i = 0; i < rs->md.raid_disks; i++) {
1336                         if (rs->dev[i].meta_dev)
1337                                 DMEMIT(" %s", rs->dev[i].meta_dev->name);
1338                         else
1339                                 DMEMIT(" -");
1340
1341                         if (rs->dev[i].data_dev)
1342                                 DMEMIT(" %s", rs->dev[i].data_dev->name);
1343                         else
1344                                 DMEMIT(" -");
1345                 }
1346         }
1347 }
1348
1349 static int raid_iterate_devices(struct dm_target *ti, iterate_devices_callout_fn fn, void *data)
1350 {
1351         struct raid_set *rs = ti->private;
1352         unsigned i;
1353         int ret = 0;
1354
1355         for (i = 0; !ret && i < rs->md.raid_disks; i++)
1356                 if (rs->dev[i].data_dev)
1357                         ret = fn(ti,
1358                                  rs->dev[i].data_dev,
1359                                  0, /* No offset on data devs */
1360                                  rs->md.dev_sectors,
1361                                  data);
1362
1363         return ret;
1364 }
1365
1366 static void raid_io_hints(struct dm_target *ti, struct queue_limits *limits)
1367 {
1368         struct raid_set *rs = ti->private;
1369         unsigned chunk_size = rs->md.chunk_sectors << 9;
1370         struct r5conf *conf = rs->md.private;
1371
1372         blk_limits_io_min(limits, chunk_size);
1373         blk_limits_io_opt(limits, chunk_size * (conf->raid_disks - conf->max_degraded));
1374 }
1375
1376 static void raid_presuspend(struct dm_target *ti)
1377 {
1378         struct raid_set *rs = ti->private;
1379
1380         md_stop_writes(&rs->md);
1381 }
1382
1383 static void raid_postsuspend(struct dm_target *ti)
1384 {
1385         struct raid_set *rs = ti->private;
1386
1387         mddev_suspend(&rs->md);
1388 }
1389
1390 static void raid_resume(struct dm_target *ti)
1391 {
1392         struct raid_set *rs = ti->private;
1393
1394         set_bit(MD_CHANGE_DEVS, &rs->md.flags);
1395         if (!rs->bitmap_loaded) {
1396                 bitmap_load(&rs->md);
1397                 rs->bitmap_loaded = 1;
1398         }
1399
1400         clear_bit(MD_RECOVERY_FROZEN, &rs->md.recovery);
1401         mddev_resume(&rs->md);
1402 }
1403
1404 static struct target_type raid_target = {
1405         .name = "raid",
1406         .version = {1, 4, 2},
1407         .module = THIS_MODULE,
1408         .ctr = raid_ctr,
1409         .dtr = raid_dtr,
1410         .map = raid_map,
1411         .status = raid_status,
1412         .iterate_devices = raid_iterate_devices,
1413         .io_hints = raid_io_hints,
1414         .presuspend = raid_presuspend,
1415         .postsuspend = raid_postsuspend,
1416         .resume = raid_resume,
1417 };
1418
1419 static int __init dm_raid_init(void)
1420 {
1421         return dm_register_target(&raid_target);
1422 }
1423
1424 static void __exit dm_raid_exit(void)
1425 {
1426         dm_unregister_target(&raid_target);
1427 }
1428
1429 module_init(dm_raid_init);
1430 module_exit(dm_raid_exit);
1431
1432 MODULE_DESCRIPTION(DM_NAME " raid4/5/6 target");
1433 MODULE_ALIAS("dm-raid1");
1434 MODULE_ALIAS("dm-raid10");
1435 MODULE_ALIAS("dm-raid4");
1436 MODULE_ALIAS("dm-raid5");
1437 MODULE_ALIAS("dm-raid6");
1438 MODULE_AUTHOR("Neil Brown <dm-devel@redhat.com>");
1439 MODULE_LICENSE("GPL");