Root/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
27struct 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
60struct 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. */
74static 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
94static char *raid10_md_layout_to_format(int layout)
95{
96    /*
97     * Bit 16 and 17 stand for "offset" and "use_far_sets"
98     * Refer to MD's raid10.c for details
99     */
100    if ((layout & 0x10000) && (layout & 0x20000))
101        return "offset";
102
103    if ((layout & 0xFF) > 1)
104        return "near";
105
106    return "far";
107}
108
109static unsigned raid10_md_layout_to_copies(int layout)
110{
111    if ((layout & 0xFF) > 1)
112        return layout & 0xFF;
113    return (layout >> 8) & 0xFF;
114}
115
116static int raid10_format_to_md_layout(char *format, unsigned copies)
117{
118    unsigned n = 1, f = 1;
119
120    if (!strcmp("near", format))
121        n = copies;
122    else
123        f = copies;
124
125    if (!strcmp("offset", format))
126        return 0x30000 | (f << 8) | n;
127
128    if (!strcmp("far", format))
129        return 0x20000 | (f << 8) | n;
130
131    return (f << 8) | n;
132}
133
134static struct raid_type *get_raid_type(char *name)
135{
136    int i;
137
138    for (i = 0; i < ARRAY_SIZE(raid_types); i++)
139        if (!strcmp(raid_types[i].name, name))
140            return &raid_types[i];
141
142    return NULL;
143}
144
145static struct raid_set *context_alloc(struct dm_target *ti, struct raid_type *raid_type, unsigned raid_devs)
146{
147    unsigned i;
148    struct raid_set *rs;
149
150    if (raid_devs <= raid_type->parity_devs) {
151        ti->error = "Insufficient number of devices";
152        return ERR_PTR(-EINVAL);
153    }
154
155    rs = kzalloc(sizeof(*rs) + raid_devs * sizeof(rs->dev[0]), GFP_KERNEL);
156    if (!rs) {
157        ti->error = "Cannot allocate raid context";
158        return ERR_PTR(-ENOMEM);
159    }
160
161    mddev_init(&rs->md);
162
163    rs->ti = ti;
164    rs->raid_type = raid_type;
165    rs->md.raid_disks = raid_devs;
166    rs->md.level = raid_type->level;
167    rs->md.new_level = rs->md.level;
168    rs->md.layout = raid_type->algorithm;
169    rs->md.new_layout = rs->md.layout;
170    rs->md.delta_disks = 0;
171    rs->md.recovery_cp = 0;
172
173    for (i = 0; i < raid_devs; i++)
174        md_rdev_init(&rs->dev[i].rdev);
175
176    /*
177     * Remaining items to be initialized by further RAID params:
178     * rs->md.persistent
179     * rs->md.external
180     * rs->md.chunk_sectors
181     * rs->md.new_chunk_sectors
182     * rs->md.dev_sectors
183     */
184
185    return rs;
186}
187
188static void context_free(struct raid_set *rs)
189{
190    int i;
191
192    for (i = 0; i < rs->md.raid_disks; i++) {
193        if (rs->dev[i].meta_dev)
194            dm_put_device(rs->ti, rs->dev[i].meta_dev);
195        md_rdev_clear(&rs->dev[i].rdev);
196        if (rs->dev[i].data_dev)
197            dm_put_device(rs->ti, rs->dev[i].data_dev);
198    }
199
200    kfree(rs);
201}
202
203/*
204 * For every device we have two words
205 * <meta_dev>: meta device name or '-' if missing
206 * <data_dev>: data device name or '-' if missing
207 *
208 * The following are permitted:
209 * - -
210 * - <data_dev>
211 * <meta_dev> <data_dev>
212 *
213 * The following is not allowed:
214 * <meta_dev> -
215 *
216 * This code parses those words. If there is a failure,
217 * the caller must use context_free to unwind the operations.
218 */
219static int dev_parms(struct raid_set *rs, char **argv)
220{
221    int i;
222    int rebuild = 0;
223    int metadata_available = 0;
224    int ret = 0;
225
226    for (i = 0; i < rs->md.raid_disks; i++, argv += 2) {
227        rs->dev[i].rdev.raid_disk = i;
228
229        rs->dev[i].meta_dev = NULL;
230        rs->dev[i].data_dev = NULL;
231
232        /*
233         * There are no offsets, since there is a separate device
234         * for data and metadata.
235         */
236        rs->dev[i].rdev.data_offset = 0;
237        rs->dev[i].rdev.mddev = &rs->md;
238
239        if (strcmp(argv[0], "-")) {
240            ret = dm_get_device(rs->ti, argv[0],
241                        dm_table_get_mode(rs->ti->table),
242                        &rs->dev[i].meta_dev);
243            rs->ti->error = "RAID metadata device lookup failure";
244            if (ret)
245                return ret;
246
247            rs->dev[i].rdev.sb_page = alloc_page(GFP_KERNEL);
248            if (!rs->dev[i].rdev.sb_page)
249                return -ENOMEM;
250        }
251
252        if (!strcmp(argv[1], "-")) {
253            if (!test_bit(In_sync, &rs->dev[i].rdev.flags) &&
254                (!rs->dev[i].rdev.recovery_offset)) {
255                rs->ti->error = "Drive designated for rebuild not specified";
256                return -EINVAL;
257            }
258
259            rs->ti->error = "No data device supplied with metadata device";
260            if (rs->dev[i].meta_dev)
261                return -EINVAL;
262
263            continue;
264        }
265
266        ret = dm_get_device(rs->ti, argv[1],
267                    dm_table_get_mode(rs->ti->table),
268                    &rs->dev[i].data_dev);
269        if (ret) {
270            rs->ti->error = "RAID device lookup failure";
271            return ret;
272        }
273
274        if (rs->dev[i].meta_dev) {
275            metadata_available = 1;
276            rs->dev[i].rdev.meta_bdev = rs->dev[i].meta_dev->bdev;
277        }
278        rs->dev[i].rdev.bdev = rs->dev[i].data_dev->bdev;
279        list_add(&rs->dev[i].rdev.same_set, &rs->md.disks);
280        if (!test_bit(In_sync, &rs->dev[i].rdev.flags))
281            rebuild++;
282    }
283
284    if (metadata_available) {
285        rs->md.external = 0;
286        rs->md.persistent = 1;
287        rs->md.major_version = 2;
288    } else if (rebuild && !rs->md.recovery_cp) {
289        /*
290         * Without metadata, we will not be able to tell if the array
291         * is in-sync or not - we must assume it is not. Therefore,
292         * it is impossible to rebuild a drive.
293         *
294         * Even if there is metadata, the on-disk information may
295         * indicate that the array is not in-sync and it will then
296         * fail at that time.
297         *
298         * User could specify 'nosync' option if desperate.
299         */
300        DMERR("Unable to rebuild drive while array is not in-sync");
301        rs->ti->error = "RAID device lookup failure";
302        return -EINVAL;
303    }
304
305    return 0;
306}
307
308/*
309 * validate_region_size
310 * @rs
311 * @region_size: region size in sectors. If 0, pick a size (4MiB default).
312 *
313 * Set rs->md.bitmap_info.chunksize (which really refers to 'region size').
314 * Ensure that (ti->len/region_size < 2^21) - required by MD bitmap.
315 *
316 * Returns: 0 on success, -EINVAL on failure.
317 */
318static int validate_region_size(struct raid_set *rs, unsigned long region_size)
319{
320    unsigned long min_region_size = rs->ti->len / (1 << 21);
321
322    if (!region_size) {
323        /*
324         * Choose a reasonable default. All figures in sectors.
325         */
326        if (min_region_size > (1 << 13)) {
327            /* If not a power of 2, make it the next power of 2 */
328            if (min_region_size & (min_region_size - 1))
329                region_size = 1 << fls(region_size);
330            DMINFO("Choosing default region size of %lu sectors",
331                   region_size);
332        } else {
333            DMINFO("Choosing default region size of 4MiB");
334            region_size = 1 << 13; /* sectors */
335        }
336    } else {
337        /*
338         * Validate user-supplied value.
339         */
340        if (region_size > rs->ti->len) {
341            rs->ti->error = "Supplied region size is too large";
342            return -EINVAL;
343        }
344
345        if (region_size < min_region_size) {
346            DMERR("Supplied region_size (%lu sectors) below minimum (%lu)",
347                  region_size, min_region_size);
348            rs->ti->error = "Supplied region size is too small";
349            return -EINVAL;
350        }
351
352        if (!is_power_of_2(region_size)) {
353            rs->ti->error = "Region size is not a power of 2";
354            return -EINVAL;
355        }
356
357        if (region_size < rs->md.chunk_sectors) {
358            rs->ti->error = "Region size is smaller than the chunk size";
359            return -EINVAL;
360        }
361    }
362
363    /*
364     * Convert sectors to bytes.
365     */
366    rs->md.bitmap_info.chunksize = (region_size << 9);
367
368    return 0;
369}
370
371/*
372 * validate_raid_redundancy
373 * @rs
374 *
375 * Determine if there are enough devices in the array that haven't
376 * failed (or are being rebuilt) to form a usable array.
377 *
378 * Returns: 0 on success, -EINVAL on failure.
379 */
380static int validate_raid_redundancy(struct raid_set *rs)
381{
382    unsigned i, rebuild_cnt = 0;
383    unsigned rebuilds_per_group, copies, d;
384    unsigned group_size, last_group_start;
385
386    for (i = 0; i < rs->md.raid_disks; i++)
387        if (!test_bit(In_sync, &rs->dev[i].rdev.flags) ||
388            !rs->dev[i].rdev.sb_page)
389            rebuild_cnt++;
390
391    switch (rs->raid_type->level) {
392    case 1:
393        if (rebuild_cnt >= rs->md.raid_disks)
394            goto too_many;
395        break;
396    case 4:
397    case 5:
398    case 6:
399        if (rebuild_cnt > rs->raid_type->parity_devs)
400            goto too_many;
401        break;
402    case 10:
403        copies = raid10_md_layout_to_copies(rs->md.layout);
404        if (rebuild_cnt < copies)
405            break;
406
407        /*
408         * It is possible to have a higher rebuild count for RAID10,
409         * as long as the failed devices occur in different mirror
410         * groups (i.e. different stripes).
411         *
412         * When checking "near" format, make sure no adjacent devices
413         * have failed beyond what can be handled. In addition to the
414         * simple case where the number of devices is a multiple of the
415         * number of copies, we must also handle cases where the number
416         * of devices is not a multiple of the number of copies.
417         * E.g. dev1 dev2 dev3 dev4 dev5
418         * A A B B C
419         * C D D E E
420         */
421        if (!strcmp("near", raid10_md_layout_to_format(rs->md.layout))) {
422            for (i = 0; i < rs->md.raid_disks * copies; i++) {
423                if (!(i % copies))
424                    rebuilds_per_group = 0;
425                d = i % rs->md.raid_disks;
426                if ((!rs->dev[d].rdev.sb_page ||
427                     !test_bit(In_sync, &rs->dev[d].rdev.flags)) &&
428                    (++rebuilds_per_group >= copies))
429                    goto too_many;
430            }
431            break;
432        }
433
434        /*
435         * When checking "far" and "offset" formats, we need to ensure
436         * that the device that holds its copy is not also dead or
437         * being rebuilt. (Note that "far" and "offset" formats only
438         * support two copies right now. These formats also only ever
439         * use the 'use_far_sets' variant.)
440         *
441         * This check is somewhat complicated by the need to account
442         * for arrays that are not a multiple of (far) copies. This
443         * results in the need to treat the last (potentially larger)
444         * set differently.
445         */
446        group_size = (rs->md.raid_disks / copies);
447        last_group_start = (rs->md.raid_disks / group_size) - 1;
448        last_group_start *= group_size;
449        for (i = 0; i < rs->md.raid_disks; i++) {
450            if (!(i % copies) && !(i > last_group_start))
451                rebuilds_per_group = 0;
452            if ((!rs->dev[i].rdev.sb_page ||
453                 !test_bit(In_sync, &rs->dev[i].rdev.flags)) &&
454                (++rebuilds_per_group >= copies))
455                    goto too_many;
456        }
457        break;
458    default:
459        if (rebuild_cnt)
460            return -EINVAL;
461    }
462
463    return 0;
464
465too_many:
466    return -EINVAL;
467}
468
469/*
470 * Possible arguments are...
471 * <chunk_size> [optional_args]
472 *
473 * Argument definitions
474 * <chunk_size> The number of sectors per disk that
475 * will form the "stripe"
476 * [[no]sync] Force or prevent recovery of the
477 * entire array
478 * [rebuild <idx>] Rebuild the drive indicated by the index
479 * [daemon_sleep <ms>] Time between bitmap daemon work to
480 * clear bits
481 * [min_recovery_rate <kB/sec/disk>] Throttle RAID initialization
482 * [max_recovery_rate <kB/sec/disk>] Throttle RAID initialization
483 * [write_mostly <idx>] Indicate a write mostly drive via index
484 * [max_write_behind <sectors>] See '-write-behind=' (man mdadm)
485 * [stripe_cache <sectors>] Stripe cache size for higher RAIDs
486 * [region_size <sectors>] Defines granularity of bitmap
487 *
488 * RAID10-only options:
489 * [raid10_copies <# copies>] Number of copies. (Default: 2)
490 * [raid10_format <near|far|offset>] Layout algorithm. (Default: near)
491 */
492static int parse_raid_params(struct raid_set *rs, char **argv,
493                 unsigned num_raid_params)
494{
495    char *raid10_format = "near";
496    unsigned raid10_copies = 2;
497    unsigned i;
498    unsigned long value, region_size = 0;
499    sector_t sectors_per_dev = rs->ti->len;
500    sector_t max_io_len;
501    char *key;
502
503    /*
504     * First, parse the in-order required arguments
505     * "chunk_size" is the only argument of this type.
506     */
507    if ((strict_strtoul(argv[0], 10, &value) < 0)) {
508        rs->ti->error = "Bad chunk size";
509        return -EINVAL;
510    } else if (rs->raid_type->level == 1) {
511        if (value)
512            DMERR("Ignoring chunk size parameter for RAID 1");
513        value = 0;
514    } else if (!is_power_of_2(value)) {
515        rs->ti->error = "Chunk size must be a power of 2";
516        return -EINVAL;
517    } else if (value < 8) {
518        rs->ti->error = "Chunk size value is too small";
519        return -EINVAL;
520    }
521
522    rs->md.new_chunk_sectors = rs->md.chunk_sectors = value;
523    argv++;
524    num_raid_params--;
525
526    /*
527     * We set each individual device as In_sync with a completed
528     * 'recovery_offset'. If there has been a device failure or
529     * replacement then one of the following cases applies:
530     *
531     * 1) User specifies 'rebuild'.
532     * - Device is reset when param is read.
533     * 2) A new device is supplied.
534     * - No matching superblock found, resets device.
535     * 3) Device failure was transient and returns on reload.
536     * - Failure noticed, resets device for bitmap replay.
537     * 4) Device hadn't completed recovery after previous failure.
538     * - Superblock is read and overrides recovery_offset.
539     *
540     * What is found in the superblocks of the devices is always
541     * authoritative, unless 'rebuild' or '[no]sync' was specified.
542     */
543    for (i = 0; i < rs->md.raid_disks; i++) {
544        set_bit(In_sync, &rs->dev[i].rdev.flags);
545        rs->dev[i].rdev.recovery_offset = MaxSector;
546    }
547
548    /*
549     * Second, parse the unordered optional arguments
550     */
551    for (i = 0; i < num_raid_params; i++) {
552        if (!strcasecmp(argv[i], "nosync")) {
553            rs->md.recovery_cp = MaxSector;
554            rs->print_flags |= DMPF_NOSYNC;
555            continue;
556        }
557        if (!strcasecmp(argv[i], "sync")) {
558            rs->md.recovery_cp = 0;
559            rs->print_flags |= DMPF_SYNC;
560            continue;
561        }
562
563        /* The rest of the optional arguments come in key/value pairs */
564        if ((i + 1) >= num_raid_params) {
565            rs->ti->error = "Wrong number of raid parameters given";
566            return -EINVAL;
567        }
568
569        key = argv[i++];
570
571        /* Parameters that take a string value are checked here. */
572        if (!strcasecmp(key, "raid10_format")) {
573            if (rs->raid_type->level != 10) {
574                rs->ti->error = "'raid10_format' is an invalid parameter for this RAID type";
575                return -EINVAL;
576            }
577            if (strcmp("near", argv[i]) &&
578                strcmp("far", argv[i]) &&
579                strcmp("offset", argv[i])) {
580                rs->ti->error = "Invalid 'raid10_format' value given";
581                return -EINVAL;
582            }
583            raid10_format = argv[i];
584            rs->print_flags |= DMPF_RAID10_FORMAT;
585            continue;
586        }
587
588        if (strict_strtoul(argv[i], 10, &value) < 0) {
589            rs->ti->error = "Bad numerical argument given in raid params";
590            return -EINVAL;
591        }
592
593        /* Parameters that take a numeric value are checked here */
594        if (!strcasecmp(key, "rebuild")) {
595            if (value >= rs->md.raid_disks) {
596                rs->ti->error = "Invalid rebuild index given";
597                return -EINVAL;
598            }
599            clear_bit(In_sync, &rs->dev[value].rdev.flags);
600            rs->dev[value].rdev.recovery_offset = 0;
601            rs->print_flags |= DMPF_REBUILD;
602        } else if (!strcasecmp(key, "write_mostly")) {
603            if (rs->raid_type->level != 1) {
604                rs->ti->error = "write_mostly option is only valid for RAID1";
605                return -EINVAL;
606            }
607            if (value >= rs->md.raid_disks) {
608                rs->ti->error = "Invalid write_mostly drive index given";
609                return -EINVAL;
610            }
611            set_bit(WriteMostly, &rs->dev[value].rdev.flags);
612        } else if (!strcasecmp(key, "max_write_behind")) {
613            if (rs->raid_type->level != 1) {
614                rs->ti->error = "max_write_behind option is only valid for RAID1";
615                return -EINVAL;
616            }
617            rs->print_flags |= DMPF_MAX_WRITE_BEHIND;
618
619            /*
620             * In device-mapper, we specify things in sectors, but
621             * MD records this value in kB
622             */
623            value /= 2;
624            if (value > COUNTER_MAX) {
625                rs->ti->error = "Max write-behind limit out of range";
626                return -EINVAL;
627            }
628            rs->md.bitmap_info.max_write_behind = value;
629        } else if (!strcasecmp(key, "daemon_sleep")) {
630            rs->print_flags |= DMPF_DAEMON_SLEEP;
631            if (!value || (value > MAX_SCHEDULE_TIMEOUT)) {
632                rs->ti->error = "daemon sleep period out of range";
633                return -EINVAL;
634            }
635            rs->md.bitmap_info.daemon_sleep = value;
636        } else if (!strcasecmp(key, "stripe_cache")) {
637            rs->print_flags |= DMPF_STRIPE_CACHE;
638
639            /*
640             * In device-mapper, we specify things in sectors, but
641             * MD records this value in kB
642             */
643            value /= 2;
644
645            if ((rs->raid_type->level != 5) &&
646                (rs->raid_type->level != 6)) {
647                rs->ti->error = "Inappropriate argument: stripe_cache";
648                return -EINVAL;
649            }
650            if (raid5_set_cache_size(&rs->md, (int)value)) {
651                rs->ti->error = "Bad stripe_cache size";
652                return -EINVAL;
653            }
654        } else if (!strcasecmp(key, "min_recovery_rate")) {
655            rs->print_flags |= DMPF_MIN_RECOVERY_RATE;
656            if (value > INT_MAX) {
657                rs->ti->error = "min_recovery_rate out of range";
658                return -EINVAL;
659            }
660            rs->md.sync_speed_min = (int)value;
661        } else if (!strcasecmp(key, "max_recovery_rate")) {
662            rs->print_flags |= DMPF_MAX_RECOVERY_RATE;
663            if (value > INT_MAX) {
664                rs->ti->error = "max_recovery_rate out of range";
665                return -EINVAL;
666            }
667            rs->md.sync_speed_max = (int)value;
668        } else if (!strcasecmp(key, "region_size")) {
669            rs->print_flags |= DMPF_REGION_SIZE;
670            region_size = value;
671        } else if (!strcasecmp(key, "raid10_copies") &&
672               (rs->raid_type->level == 10)) {
673            if ((value < 2) || (value > 0xFF)) {
674                rs->ti->error = "Bad value for 'raid10_copies'";
675                return -EINVAL;
676            }
677            rs->print_flags |= DMPF_RAID10_COPIES;
678            raid10_copies = value;
679        } else {
680            DMERR("Unable to parse RAID parameter: %s", key);
681            rs->ti->error = "Unable to parse RAID parameters";
682            return -EINVAL;
683        }
684    }
685
686    if (validate_region_size(rs, region_size))
687        return -EINVAL;
688
689    if (rs->md.chunk_sectors)
690        max_io_len = rs->md.chunk_sectors;
691    else
692        max_io_len = region_size;
693
694    if (dm_set_target_max_io_len(rs->ti, max_io_len))
695        return -EINVAL;
696
697    if (rs->raid_type->level == 10) {
698        if (raid10_copies > rs->md.raid_disks) {
699            rs->ti->error = "Not enough devices to satisfy specification";
700            return -EINVAL;
701        }
702
703        /*
704         * If the format is not "near", we only support
705         * two copies at the moment.
706         */
707        if (strcmp("near", raid10_format) && (raid10_copies > 2)) {
708            rs->ti->error = "Too many copies for given RAID10 format.";
709            return -EINVAL;
710        }
711
712        /* (Len * #mirrors) / #devices */
713        sectors_per_dev = rs->ti->len * raid10_copies;
714        sector_div(sectors_per_dev, rs->md.raid_disks);
715
716        rs->md.layout = raid10_format_to_md_layout(raid10_format,
717                               raid10_copies);
718        rs->md.new_layout = rs->md.layout;
719    } else if ((rs->raid_type->level > 1) &&
720           sector_div(sectors_per_dev,
721                  (rs->md.raid_disks - rs->raid_type->parity_devs))) {
722        rs->ti->error = "Target length not divisible by number of data devices";
723        return -EINVAL;
724    }
725    rs->md.dev_sectors = sectors_per_dev;
726
727    /* Assume there are no metadata devices until the drives are parsed */
728    rs->md.persistent = 0;
729    rs->md.external = 1;
730
731    return 0;
732}
733
734static void do_table_event(struct work_struct *ws)
735{
736    struct raid_set *rs = container_of(ws, struct raid_set, md.event_work);
737
738    dm_table_event(rs->ti->table);
739}
740
741static int raid_is_congested(struct dm_target_callbacks *cb, int bits)
742{
743    struct raid_set *rs = container_of(cb, struct raid_set, callbacks);
744
745    if (rs->raid_type->level == 1)
746        return md_raid1_congested(&rs->md, bits);
747
748    if (rs->raid_type->level == 10)
749        return md_raid10_congested(&rs->md, bits);
750
751    return md_raid5_congested(&rs->md, bits);
752}
753
754/*
755 * This structure is never routinely used by userspace, unlike md superblocks.
756 * Devices with this superblock should only ever be accessed via device-mapper.
757 */
758#define DM_RAID_MAGIC 0x64526D44
759struct dm_raid_superblock {
760    __le32 magic; /* "DmRd" */
761    __le32 features; /* Used to indicate possible future changes */
762
763    __le32 num_devices; /* Number of devices in this array. (Max 64) */
764    __le32 array_position; /* The position of this drive in the array */
765
766    __le64 events; /* Incremented by md when superblock updated */
767    __le64 failed_devices; /* Bit field of devices to indicate failures */
768
769    /*
770     * This offset tracks the progress of the repair or replacement of
771     * an individual drive.
772     */
773    __le64 disk_recovery_offset;
774
775    /*
776     * This offset tracks the progress of the initial array
777     * synchronisation/parity calculation.
778     */
779    __le64 array_resync_offset;
780
781    /*
782     * RAID characteristics
783     */
784    __le32 level;
785    __le32 layout;
786    __le32 stripe_sectors;
787
788    __u8 pad[452]; /* Round struct to 512 bytes. */
789                /* Always set to 0 when writing. */
790} __packed;
791
792static int read_disk_sb(struct md_rdev *rdev, int size)
793{
794    BUG_ON(!rdev->sb_page);
795
796    if (rdev->sb_loaded)
797        return 0;
798
799    if (!sync_page_io(rdev, 0, size, rdev->sb_page, READ, 1)) {
800        DMERR("Failed to read superblock of device at position %d",
801              rdev->raid_disk);
802        md_error(rdev->mddev, rdev);
803        return -EINVAL;
804    }
805
806    rdev->sb_loaded = 1;
807
808    return 0;
809}
810
811static void super_sync(struct mddev *mddev, struct md_rdev *rdev)
812{
813    int i;
814    uint64_t failed_devices;
815    struct dm_raid_superblock *sb;
816    struct raid_set *rs = container_of(mddev, struct raid_set, md);
817
818    sb = page_address(rdev->sb_page);
819    failed_devices = le64_to_cpu(sb->failed_devices);
820
821    for (i = 0; i < mddev->raid_disks; i++)
822        if (!rs->dev[i].data_dev ||
823            test_bit(Faulty, &(rs->dev[i].rdev.flags)))
824            failed_devices |= (1ULL << i);
825
826    memset(sb, 0, sizeof(*sb));
827
828    sb->magic = cpu_to_le32(DM_RAID_MAGIC);
829    sb->features = cpu_to_le32(0); /* No features yet */
830
831    sb->num_devices = cpu_to_le32(mddev->raid_disks);
832    sb->array_position = cpu_to_le32(rdev->raid_disk);
833
834    sb->events = cpu_to_le64(mddev->events);
835    sb->failed_devices = cpu_to_le64(failed_devices);
836
837    sb->disk_recovery_offset = cpu_to_le64(rdev->recovery_offset);
838    sb->array_resync_offset = cpu_to_le64(mddev->recovery_cp);
839
840    sb->level = cpu_to_le32(mddev->level);
841    sb->layout = cpu_to_le32(mddev->layout);
842    sb->stripe_sectors = cpu_to_le32(mddev->chunk_sectors);
843}
844
845/*
846 * super_load
847 *
848 * This function creates a superblock if one is not found on the device
849 * and will decide which superblock to use if there's a choice.
850 *
851 * Return: 1 if use rdev, 0 if use refdev, -Exxx otherwise
852 */
853static int super_load(struct md_rdev *rdev, struct md_rdev *refdev)
854{
855    int ret;
856    struct dm_raid_superblock *sb;
857    struct dm_raid_superblock *refsb;
858    uint64_t events_sb, events_refsb;
859
860    rdev->sb_start = 0;
861    rdev->sb_size = sizeof(*sb);
862
863    ret = read_disk_sb(rdev, rdev->sb_size);
864    if (ret)
865        return ret;
866
867    sb = page_address(rdev->sb_page);
868
869    /*
870     * Two cases that we want to write new superblocks and rebuild:
871     * 1) New device (no matching magic number)
872     * 2) Device specified for rebuild (!In_sync w/ offset == 0)
873     */
874    if ((sb->magic != cpu_to_le32(DM_RAID_MAGIC)) ||
875        (!test_bit(In_sync, &rdev->flags) && !rdev->recovery_offset)) {
876        super_sync(rdev->mddev, rdev);
877
878        set_bit(FirstUse, &rdev->flags);
879
880        /* Force writing of superblocks to disk */
881        set_bit(MD_CHANGE_DEVS, &rdev->mddev->flags);
882
883        /* Any superblock is better than none, choose that if given */
884        return refdev ? 0 : 1;
885    }
886
887    if (!refdev)
888        return 1;
889
890    events_sb = le64_to_cpu(sb->events);
891
892    refsb = page_address(refdev->sb_page);
893    events_refsb = le64_to_cpu(refsb->events);
894
895    return (events_sb > events_refsb) ? 1 : 0;
896}
897
898static int super_init_validation(struct mddev *mddev, struct md_rdev *rdev)
899{
900    int role;
901    struct raid_set *rs = container_of(mddev, struct raid_set, md);
902    uint64_t events_sb;
903    uint64_t failed_devices;
904    struct dm_raid_superblock *sb;
905    uint32_t new_devs = 0;
906    uint32_t rebuilds = 0;
907    struct md_rdev *r;
908    struct dm_raid_superblock *sb2;
909
910    sb = page_address(rdev->sb_page);
911    events_sb = le64_to_cpu(sb->events);
912    failed_devices = le64_to_cpu(sb->failed_devices);
913
914    /*
915     * Initialise to 1 if this is a new superblock.
916     */
917    mddev->events = events_sb ? : 1;
918
919    /*
920     * Reshaping is not currently allowed
921     */
922    if (le32_to_cpu(sb->level) != mddev->level) {
923        DMERR("Reshaping arrays not yet supported. (RAID level change)");
924        return -EINVAL;
925    }
926    if (le32_to_cpu(sb->layout) != mddev->layout) {
927        DMERR("Reshaping arrays not yet supported. (RAID layout change)");
928        DMERR(" 0x%X vs 0x%X", le32_to_cpu(sb->layout), mddev->layout);
929        DMERR(" Old layout: %s w/ %d copies",
930              raid10_md_layout_to_format(le32_to_cpu(sb->layout)),
931              raid10_md_layout_to_copies(le32_to_cpu(sb->layout)));
932        DMERR(" New layout: %s w/ %d copies",
933              raid10_md_layout_to_format(mddev->layout),
934              raid10_md_layout_to_copies(mddev->layout));
935        return -EINVAL;
936    }
937    if (le32_to_cpu(sb->stripe_sectors) != mddev->chunk_sectors) {
938        DMERR("Reshaping arrays not yet supported. (stripe sectors change)");
939        return -EINVAL;
940    }
941
942    /* We can only change the number of devices in RAID1 right now */
943    if ((rs->raid_type->level != 1) &&
944        (le32_to_cpu(sb->num_devices) != mddev->raid_disks)) {
945        DMERR("Reshaping arrays not yet supported. (device count change)");
946        return -EINVAL;
947    }
948
949    if (!(rs->print_flags & (DMPF_SYNC | DMPF_NOSYNC)))
950        mddev->recovery_cp = le64_to_cpu(sb->array_resync_offset);
951
952    /*
953     * During load, we set FirstUse if a new superblock was written.
954     * There are two reasons we might not have a superblock:
955     * 1) The array is brand new - in which case, all of the
956     * devices must have their In_sync bit set. Also,
957     * recovery_cp must be 0, unless forced.
958     * 2) This is a new device being added to an old array
959     * and the new device needs to be rebuilt - in which
960     * case the In_sync bit will /not/ be set and
961     * recovery_cp must be MaxSector.
962     */
963    rdev_for_each(r, mddev) {
964        if (!test_bit(In_sync, &r->flags)) {
965            DMINFO("Device %d specified for rebuild: "
966                   "Clearing superblock", r->raid_disk);
967            rebuilds++;
968        } else if (test_bit(FirstUse, &r->flags))
969            new_devs++;
970    }
971
972    if (!rebuilds) {
973        if (new_devs == mddev->raid_disks) {
974            DMINFO("Superblocks created for new array");
975            set_bit(MD_ARRAY_FIRST_USE, &mddev->flags);
976        } else if (new_devs) {
977            DMERR("New device injected "
978                  "into existing array without 'rebuild' "
979                  "parameter specified");
980            return -EINVAL;
981        }
982    } else if (new_devs) {
983        DMERR("'rebuild' devices cannot be "
984              "injected into an array with other first-time devices");
985        return -EINVAL;
986    } else if (mddev->recovery_cp != MaxSector) {
987        DMERR("'rebuild' specified while array is not in-sync");
988        return -EINVAL;
989    }
990
991    /*
992     * Now we set the Faulty bit for those devices that are
993     * recorded in the superblock as failed.
994     */
995    rdev_for_each(r, mddev) {
996        if (!r->sb_page)
997            continue;
998        sb2 = page_address(r->sb_page);
999        sb2->failed_devices = 0;
1000
1001        /*
1002         * Check for any device re-ordering.
1003         */
1004        if (!test_bit(FirstUse, &r->flags) && (r->raid_disk >= 0)) {
1005            role = le32_to_cpu(sb2->array_position);
1006            if (role != r->raid_disk) {
1007                if (rs->raid_type->level != 1) {
1008                    rs->ti->error = "Cannot change device "
1009                        "positions in RAID array";
1010                    return -EINVAL;
1011                }
1012                DMINFO("RAID1 device #%d now at position #%d",
1013                       role, r->raid_disk);
1014            }
1015
1016            /*
1017             * Partial recovery is performed on
1018             * returning failed devices.
1019             */
1020            if (failed_devices & (1 << role))
1021                set_bit(Faulty, &r->flags);
1022        }
1023    }
1024
1025    return 0;
1026}
1027
1028static int super_validate(struct mddev *mddev, struct md_rdev *rdev)
1029{
1030    struct dm_raid_superblock *sb = page_address(rdev->sb_page);
1031
1032    /*
1033     * If mddev->events is not set, we know we have not yet initialized
1034     * the array.
1035     */
1036    if (!mddev->events && super_init_validation(mddev, rdev))
1037        return -EINVAL;
1038
1039    mddev->bitmap_info.offset = 4096 >> 9; /* Enable bitmap creation */
1040    rdev->mddev->bitmap_info.default_offset = 4096 >> 9;
1041    if (!test_bit(FirstUse, &rdev->flags)) {
1042        rdev->recovery_offset = le64_to_cpu(sb->disk_recovery_offset);
1043        if (rdev->recovery_offset != MaxSector)
1044            clear_bit(In_sync, &rdev->flags);
1045    }
1046
1047    /*
1048     * If a device comes back, set it as not In_sync and no longer faulty.
1049     */
1050    if (test_bit(Faulty, &rdev->flags)) {
1051        clear_bit(Faulty, &rdev->flags);
1052        clear_bit(In_sync, &rdev->flags);
1053        rdev->saved_raid_disk = rdev->raid_disk;
1054        rdev->recovery_offset = 0;
1055    }
1056
1057    clear_bit(FirstUse, &rdev->flags);
1058
1059    return 0;
1060}
1061
1062/*
1063 * Analyse superblocks and select the freshest.
1064 */
1065static int analyse_superblocks(struct dm_target *ti, struct raid_set *rs)
1066{
1067    int ret;
1068    struct raid_dev *dev;
1069    struct md_rdev *rdev, *tmp, *freshest;
1070    struct mddev *mddev = &rs->md;
1071
1072    freshest = NULL;
1073    rdev_for_each_safe(rdev, tmp, mddev) {
1074        /*
1075         * Skipping super_load due to DMPF_SYNC will cause
1076         * the array to undergo initialization again as
1077         * though it were new. This is the intended effect
1078         * of the "sync" directive.
1079         *
1080         * When reshaping capability is added, we must ensure
1081         * that the "sync" directive is disallowed during the
1082         * reshape.
1083         */
1084        if (rs->print_flags & DMPF_SYNC)
1085            continue;
1086
1087        if (!rdev->meta_bdev)
1088            continue;
1089
1090        ret = super_load(rdev, freshest);
1091
1092        switch (ret) {
1093        case 1:
1094            freshest = rdev;
1095            break;
1096        case 0:
1097            break;
1098        default:
1099            dev = container_of(rdev, struct raid_dev, rdev);
1100            if (dev->meta_dev)
1101                dm_put_device(ti, dev->meta_dev);
1102
1103            dev->meta_dev = NULL;
1104            rdev->meta_bdev = NULL;
1105
1106            if (rdev->sb_page)
1107                put_page(rdev->sb_page);
1108
1109            rdev->sb_page = NULL;
1110
1111            rdev->sb_loaded = 0;
1112
1113            /*
1114             * We might be able to salvage the data device
1115             * even though the meta device has failed. For
1116             * now, we behave as though '- -' had been
1117             * set for this device in the table.
1118             */
1119            if (dev->data_dev)
1120                dm_put_device(ti, dev->data_dev);
1121
1122            dev->data_dev = NULL;
1123            rdev->bdev = NULL;
1124
1125            list_del(&rdev->same_set);
1126        }
1127    }
1128
1129    if (!freshest)
1130        return 0;
1131
1132    if (validate_raid_redundancy(rs)) {
1133        rs->ti->error = "Insufficient redundancy to activate array";
1134        return -EINVAL;
1135    }
1136
1137    /*
1138     * Validation of the freshest device provides the source of
1139     * validation for the remaining devices.
1140     */
1141    ti->error = "Unable to assemble array: Invalid superblocks";
1142    if (super_validate(mddev, freshest))
1143        return -EINVAL;
1144
1145    rdev_for_each(rdev, mddev)
1146        if ((rdev != freshest) && super_validate(mddev, rdev))
1147            return -EINVAL;
1148
1149    return 0;
1150}
1151
1152/*
1153 * Construct a RAID4/5/6 mapping:
1154 * Args:
1155 * <raid_type> <#raid_params> <raid_params> \
1156 * <#raid_devs> { <meta_dev1> <dev1> .. <meta_devN> <devN> }
1157 *
1158 * <raid_params> varies by <raid_type>. See 'parse_raid_params' for
1159 * details on possible <raid_params>.
1160 */
1161static int raid_ctr(struct dm_target *ti, unsigned argc, char **argv)
1162{
1163    int ret;
1164    struct raid_type *rt;
1165    unsigned long num_raid_params, num_raid_devs;
1166    struct raid_set *rs = NULL;
1167
1168    /* Must have at least <raid_type> <#raid_params> */
1169    if (argc < 2) {
1170        ti->error = "Too few arguments";
1171        return -EINVAL;
1172    }
1173
1174    /* raid type */
1175    rt = get_raid_type(argv[0]);
1176    if (!rt) {
1177        ti->error = "Unrecognised raid_type";
1178        return -EINVAL;
1179    }
1180    argc--;
1181    argv++;
1182
1183    /* number of RAID parameters */
1184    if (strict_strtoul(argv[0], 10, &num_raid_params) < 0) {
1185        ti->error = "Cannot understand number of RAID parameters";
1186        return -EINVAL;
1187    }
1188    argc--;
1189    argv++;
1190
1191    /* Skip over RAID params for now and find out # of devices */
1192    if (num_raid_params + 1 > argc) {
1193        ti->error = "Arguments do not agree with counts given";
1194        return -EINVAL;
1195    }
1196
1197    if ((strict_strtoul(argv[num_raid_params], 10, &num_raid_devs) < 0) ||
1198        (num_raid_devs >= INT_MAX)) {
1199        ti->error = "Cannot understand number of raid devices";
1200        return -EINVAL;
1201    }
1202
1203    rs = context_alloc(ti, rt, (unsigned)num_raid_devs);
1204    if (IS_ERR(rs))
1205        return PTR_ERR(rs);
1206
1207    ret = parse_raid_params(rs, argv, (unsigned)num_raid_params);
1208    if (ret)
1209        goto bad;
1210
1211    ret = -EINVAL;
1212
1213    argc -= num_raid_params + 1; /* +1: we already have num_raid_devs */
1214    argv += num_raid_params + 1;
1215
1216    if (argc != (num_raid_devs * 2)) {
1217        ti->error = "Supplied RAID devices does not match the count given";
1218        goto bad;
1219    }
1220
1221    ret = dev_parms(rs, argv);
1222    if (ret)
1223        goto bad;
1224
1225    rs->md.sync_super = super_sync;
1226    ret = analyse_superblocks(ti, rs);
1227    if (ret)
1228        goto bad;
1229
1230    INIT_WORK(&rs->md.event_work, do_table_event);
1231    ti->private = rs;
1232    ti->num_flush_bios = 1;
1233
1234    mutex_lock(&rs->md.reconfig_mutex);
1235    ret = md_run(&rs->md);
1236    rs->md.in_sync = 0; /* Assume already marked dirty */
1237    mutex_unlock(&rs->md.reconfig_mutex);
1238
1239    if (ret) {
1240        ti->error = "Fail to run raid array";
1241        goto bad;
1242    }
1243
1244    if (ti->len != rs->md.array_sectors) {
1245        ti->error = "Array size does not match requested target length";
1246        ret = -EINVAL;
1247        goto size_mismatch;
1248    }
1249    rs->callbacks.congested_fn = raid_is_congested;
1250    dm_table_add_target_callbacks(ti->table, &rs->callbacks);
1251
1252    mddev_suspend(&rs->md);
1253    return 0;
1254
1255size_mismatch:
1256    md_stop(&rs->md);
1257bad:
1258    context_free(rs);
1259
1260    return ret;
1261}
1262
1263static void raid_dtr(struct dm_target *ti)
1264{
1265    struct raid_set *rs = ti->private;
1266
1267    list_del_init(&rs->callbacks.list);
1268    md_stop(&rs->md);
1269    context_free(rs);
1270}
1271
1272static int raid_map(struct dm_target *ti, struct bio *bio)
1273{
1274    struct raid_set *rs = ti->private;
1275    struct mddev *mddev = &rs->md;
1276
1277    mddev->pers->make_request(mddev, bio);
1278
1279    return DM_MAPIO_SUBMITTED;
1280}
1281
1282static void raid_status(struct dm_target *ti, status_type_t type,
1283            unsigned status_flags, char *result, unsigned maxlen)
1284{
1285    struct raid_set *rs = ti->private;
1286    unsigned raid_param_cnt = 1; /* at least 1 for chunksize */
1287    unsigned sz = 0;
1288    int i, array_in_sync = 0;
1289    sector_t sync;
1290
1291    switch (type) {
1292    case STATUSTYPE_INFO:
1293        DMEMIT("%s %d ", rs->raid_type->name, rs->md.raid_disks);
1294
1295        if (test_bit(MD_RECOVERY_RUNNING, &rs->md.recovery))
1296            sync = rs->md.curr_resync_completed;
1297        else
1298            sync = rs->md.recovery_cp;
1299
1300        if (sync >= rs->md.resync_max_sectors) {
1301            array_in_sync = 1;
1302            sync = rs->md.resync_max_sectors;
1303        } else {
1304            /*
1305             * The array may be doing an initial sync, or it may
1306             * be rebuilding individual components. If all the
1307             * devices are In_sync, then it is the array that is
1308             * being initialized.
1309             */
1310            for (i = 0; i < rs->md.raid_disks; i++)
1311                if (!test_bit(In_sync, &rs->dev[i].rdev.flags))
1312                    array_in_sync = 1;
1313        }
1314        /*
1315         * Status characters:
1316         * 'D' = Dead/Failed device
1317         * 'a' = Alive but not in-sync
1318         * 'A' = Alive and in-sync
1319         */
1320        for (i = 0; i < rs->md.raid_disks; i++) {
1321            if (test_bit(Faulty, &rs->dev[i].rdev.flags))
1322                DMEMIT("D");
1323            else if (!array_in_sync ||
1324                 !test_bit(In_sync, &rs->dev[i].rdev.flags))
1325                DMEMIT("a");
1326            else
1327                DMEMIT("A");
1328        }
1329
1330        /*
1331         * In-sync ratio:
1332         * The in-sync ratio shows the progress of:
1333         * - Initializing the array
1334         * - Rebuilding a subset of devices of the array
1335         * The user can distinguish between the two by referring
1336         * to the status characters.
1337         */
1338        DMEMIT(" %llu/%llu",
1339               (unsigned long long) sync,
1340               (unsigned long long) rs->md.resync_max_sectors);
1341
1342        break;
1343    case STATUSTYPE_TABLE:
1344        /* The string you would use to construct this array */
1345        for (i = 0; i < rs->md.raid_disks; i++) {
1346            if ((rs->print_flags & DMPF_REBUILD) &&
1347                rs->dev[i].data_dev &&
1348                !test_bit(In_sync, &rs->dev[i].rdev.flags))
1349                raid_param_cnt += 2; /* for rebuilds */
1350            if (rs->dev[i].data_dev &&
1351                test_bit(WriteMostly, &rs->dev[i].rdev.flags))
1352                raid_param_cnt += 2;
1353        }
1354
1355        raid_param_cnt += (hweight32(rs->print_flags & ~DMPF_REBUILD) * 2);
1356        if (rs->print_flags & (DMPF_SYNC | DMPF_NOSYNC))
1357            raid_param_cnt--;
1358
1359        DMEMIT("%s %u %u", rs->raid_type->name,
1360               raid_param_cnt, rs->md.chunk_sectors);
1361
1362        if ((rs->print_flags & DMPF_SYNC) &&
1363            (rs->md.recovery_cp == MaxSector))
1364            DMEMIT(" sync");
1365        if (rs->print_flags & DMPF_NOSYNC)
1366            DMEMIT(" nosync");
1367
1368        for (i = 0; i < rs->md.raid_disks; i++)
1369            if ((rs->print_flags & DMPF_REBUILD) &&
1370                rs->dev[i].data_dev &&
1371                !test_bit(In_sync, &rs->dev[i].rdev.flags))
1372                DMEMIT(" rebuild %u", i);
1373
1374        if (rs->print_flags & DMPF_DAEMON_SLEEP)
1375            DMEMIT(" daemon_sleep %lu",
1376                   rs->md.bitmap_info.daemon_sleep);
1377
1378        if (rs->print_flags & DMPF_MIN_RECOVERY_RATE)
1379            DMEMIT(" min_recovery_rate %d", rs->md.sync_speed_min);
1380
1381        if (rs->print_flags & DMPF_MAX_RECOVERY_RATE)
1382            DMEMIT(" max_recovery_rate %d", rs->md.sync_speed_max);
1383
1384        for (i = 0; i < rs->md.raid_disks; i++)
1385            if (rs->dev[i].data_dev &&
1386                test_bit(WriteMostly, &rs->dev[i].rdev.flags))
1387                DMEMIT(" write_mostly %u", i);
1388
1389        if (rs->print_flags & DMPF_MAX_WRITE_BEHIND)
1390            DMEMIT(" max_write_behind %lu",
1391                   rs->md.bitmap_info.max_write_behind);
1392
1393        if (rs->print_flags & DMPF_STRIPE_CACHE) {
1394            struct r5conf *conf = rs->md.private;
1395
1396            /* convert from kiB to sectors */
1397            DMEMIT(" stripe_cache %d",
1398                   conf ? conf->max_nr_stripes * 2 : 0);
1399        }
1400
1401        if (rs->print_flags & DMPF_REGION_SIZE)
1402            DMEMIT(" region_size %lu",
1403                   rs->md.bitmap_info.chunksize >> 9);
1404
1405        if (rs->print_flags & DMPF_RAID10_COPIES)
1406            DMEMIT(" raid10_copies %u",
1407                   raid10_md_layout_to_copies(rs->md.layout));
1408
1409        if (rs->print_flags & DMPF_RAID10_FORMAT)
1410            DMEMIT(" raid10_format %s",
1411                   raid10_md_layout_to_format(rs->md.layout));
1412
1413        DMEMIT(" %d", rs->md.raid_disks);
1414        for (i = 0; i < rs->md.raid_disks; i++) {
1415            if (rs->dev[i].meta_dev)
1416                DMEMIT(" %s", rs->dev[i].meta_dev->name);
1417            else
1418                DMEMIT(" -");
1419
1420            if (rs->dev[i].data_dev)
1421                DMEMIT(" %s", rs->dev[i].data_dev->name);
1422            else
1423                DMEMIT(" -");
1424        }
1425    }
1426}
1427
1428static int raid_iterate_devices(struct dm_target *ti, iterate_devices_callout_fn fn, void *data)
1429{
1430    struct raid_set *rs = ti->private;
1431    unsigned i;
1432    int ret = 0;
1433
1434    for (i = 0; !ret && i < rs->md.raid_disks; i++)
1435        if (rs->dev[i].data_dev)
1436            ret = fn(ti,
1437                 rs->dev[i].data_dev,
1438                 0, /* No offset on data devs */
1439                 rs->md.dev_sectors,
1440                 data);
1441
1442    return ret;
1443}
1444
1445static void raid_io_hints(struct dm_target *ti, struct queue_limits *limits)
1446{
1447    struct raid_set *rs = ti->private;
1448    unsigned chunk_size = rs->md.chunk_sectors << 9;
1449    struct r5conf *conf = rs->md.private;
1450
1451    blk_limits_io_min(limits, chunk_size);
1452    blk_limits_io_opt(limits, chunk_size * (conf->raid_disks - conf->max_degraded));
1453}
1454
1455static void raid_presuspend(struct dm_target *ti)
1456{
1457    struct raid_set *rs = ti->private;
1458
1459    md_stop_writes(&rs->md);
1460}
1461
1462static void raid_postsuspend(struct dm_target *ti)
1463{
1464    struct raid_set *rs = ti->private;
1465
1466    mddev_suspend(&rs->md);
1467}
1468
1469static void raid_resume(struct dm_target *ti)
1470{
1471    struct raid_set *rs = ti->private;
1472
1473    set_bit(MD_CHANGE_DEVS, &rs->md.flags);
1474    if (!rs->bitmap_loaded) {
1475        bitmap_load(&rs->md);
1476        rs->bitmap_loaded = 1;
1477    }
1478
1479    clear_bit(MD_RECOVERY_FROZEN, &rs->md.recovery);
1480    mddev_resume(&rs->md);
1481}
1482
1483static struct target_type raid_target = {
1484    .name = "raid",
1485    .version = {1, 4, 2},
1486    .module = THIS_MODULE,
1487    .ctr = raid_ctr,
1488    .dtr = raid_dtr,
1489    .map = raid_map,
1490    .status = raid_status,
1491    .iterate_devices = raid_iterate_devices,
1492    .io_hints = raid_io_hints,
1493    .presuspend = raid_presuspend,
1494    .postsuspend = raid_postsuspend,
1495    .resume = raid_resume,
1496};
1497
1498static int __init dm_raid_init(void)
1499{
1500    DMINFO("Loading target version %u.%u.%u",
1501           raid_target.version[0],
1502           raid_target.version[1],
1503           raid_target.version[2]);
1504    return dm_register_target(&raid_target);
1505}
1506
1507static void __exit dm_raid_exit(void)
1508{
1509    dm_unregister_target(&raid_target);
1510}
1511
1512module_init(dm_raid_init);
1513module_exit(dm_raid_exit);
1514
1515MODULE_DESCRIPTION(DM_NAME " raid4/5/6 target");
1516MODULE_ALIAS("dm-raid1");
1517MODULE_ALIAS("dm-raid10");
1518MODULE_ALIAS("dm-raid4");
1519MODULE_ALIAS("dm-raid5");
1520MODULE_ALIAS("dm-raid6");
1521MODULE_AUTHOR("Neil Brown <dm-devel@redhat.com>");
1522MODULE_LICENSE("GPL");
1523

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