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	Version: linux-6.0.1 spark-3.0.0 hadoop-3.2.0-src hadoop-3.3.0-src spark-2.4.7 linux-4.15.13 hadoop-2.7.4-src Revert   Change

 /*
  * Copyright (C) 2010-2011 Neil Brown
  * Copyright (C) 2010-2018 Red Hat, Inc. All rights reserved.
  *
  * This file is released under the GPL.
  */
 
 #include <linux/slab.h>
 #include <linux/module.h>
 
 #include "md.h"
 #include "raid1.h"
 #include "raid5.h"
 #include "raid10.h"
 #include "md-bitmap.h"
 
 #include <linux/device-mapper.h>
 
 #define DM_MSG_PREFIX "raid"
 #define MAX_RAID_DEVICES    253 /* md-raid kernel limit */
 
 /*
  * Minimum sectors of free reshape space per raid device
  */
 #define MIN_FREE_RESHAPE_SPACE to_sector(4*4096)
 
 /*
  * Minimum journal space 4 MiB in sectors.
  */
 #define MIN_RAID456_JOURNAL_SPACE (4*2048)
 
 static bool devices_handle_discard_safely = false;
 
 /*
  * The following flags are used by dm-raid.c to set up the array state.
  * They must be cleared before md_run is called.
  */
 #define FirstUse 10     /* rdev flag */
 
 struct raid_dev {
     /*
      * Two DM devices, one to hold metadata and one to hold the
      * actual data/parity.  The reason for this is to not confuse
      * ti->len and give more flexibility in altering size and
      * characteristics.
      *
      * While it is possible for this device to be associated
      * with a different physical device than the data_dev, it
      * is intended for it to be the same.
      *    |--------- Physical Device ---------|
      *    |- meta_dev -|------ data_dev ------|
      */
     struct dm_dev *meta_dev;
     struct dm_dev *data_dev;
     struct md_rdev rdev;
 };
 
 /*
  * Bits for establishing rs->ctr_flags
  *
  * 1 = no flag value
  * 2 = flag with value
  */
 #define __CTR_FLAG_SYNC         0  /* 1 */ /* Not with raid0! */
 #define __CTR_FLAG_NOSYNC       1  /* 1 */ /* Not with raid0! */
 #define __CTR_FLAG_REBUILD      2  /* 2 */ /* Not with raid0! */
 #define __CTR_FLAG_DAEMON_SLEEP     3  /* 2 */ /* Not with raid0! */
 #define __CTR_FLAG_MIN_RECOVERY_RATE    4  /* 2 */ /* Not with raid0! */
 #define __CTR_FLAG_MAX_RECOVERY_RATE    5  /* 2 */ /* Not with raid0! */
 #define __CTR_FLAG_MAX_WRITE_BEHIND 6  /* 2 */ /* Only with raid1! */
 #define __CTR_FLAG_WRITE_MOSTLY     7  /* 2 */ /* Only with raid1! */
 #define __CTR_FLAG_STRIPE_CACHE     8  /* 2 */ /* Only with raid4/5/6! */
 #define __CTR_FLAG_REGION_SIZE      9  /* 2 */ /* Not with raid0! */
 #define __CTR_FLAG_RAID10_COPIES    10 /* 2 */ /* Only with raid10 */
 #define __CTR_FLAG_RAID10_FORMAT    11 /* 2 */ /* Only with raid10 */
 /* New for v1.9.0 */
 #define __CTR_FLAG_DELTA_DISKS      12 /* 2 */ /* Only with reshapable raid1/4/5/6/10! */
 #define __CTR_FLAG_DATA_OFFSET      13 /* 2 */ /* Only with reshapable raid4/5/6/10! */
 #define __CTR_FLAG_RAID10_USE_NEAR_SETS 14 /* 2 */ /* Only with raid10! */
 
 /* New for v1.10.0 */
 #define __CTR_FLAG_JOURNAL_DEV      15 /* 2 */ /* Only with raid4/5/6 (journal device)! */
 
 /* New for v1.11.1 */
 #define __CTR_FLAG_JOURNAL_MODE     16 /* 2 */ /* Only with raid4/5/6 (journal mode)! */
 
 /*
  * Flags for rs->ctr_flags field.
  */
 #define CTR_FLAG_SYNC           (1 << __CTR_FLAG_SYNC)
 #define CTR_FLAG_NOSYNC         (1 << __CTR_FLAG_NOSYNC)
 #define CTR_FLAG_REBUILD        (1 << __CTR_FLAG_REBUILD)
 #define CTR_FLAG_DAEMON_SLEEP       (1 << __CTR_FLAG_DAEMON_SLEEP)
 #define CTR_FLAG_MIN_RECOVERY_RATE  (1 << __CTR_FLAG_MIN_RECOVERY_RATE)
 #define CTR_FLAG_MAX_RECOVERY_RATE  (1 << __CTR_FLAG_MAX_RECOVERY_RATE)
 #define CTR_FLAG_MAX_WRITE_BEHIND   (1 << __CTR_FLAG_MAX_WRITE_BEHIND)
 #define CTR_FLAG_WRITE_MOSTLY       (1 << __CTR_FLAG_WRITE_MOSTLY)
 #define CTR_FLAG_STRIPE_CACHE       (1 << __CTR_FLAG_STRIPE_CACHE)
 #define CTR_FLAG_REGION_SIZE        (1 << __CTR_FLAG_REGION_SIZE)
 #define CTR_FLAG_RAID10_COPIES      (1 << __CTR_FLAG_RAID10_COPIES)
 #define CTR_FLAG_RAID10_FORMAT      (1 << __CTR_FLAG_RAID10_FORMAT)
 #define CTR_FLAG_DELTA_DISKS        (1 << __CTR_FLAG_DELTA_DISKS)
 #define CTR_FLAG_DATA_OFFSET        (1 << __CTR_FLAG_DATA_OFFSET)
 #define CTR_FLAG_RAID10_USE_NEAR_SETS   (1 << __CTR_FLAG_RAID10_USE_NEAR_SETS)
 #define CTR_FLAG_JOURNAL_DEV        (1 << __CTR_FLAG_JOURNAL_DEV)
 #define CTR_FLAG_JOURNAL_MODE       (1 << __CTR_FLAG_JOURNAL_MODE)
 
 /*
  * Definitions of various constructor flags to
  * be used in checks of valid / invalid flags
  * per raid level.
  */
 /* Define all any sync flags */
 #define CTR_FLAGS_ANY_SYNC      (CTR_FLAG_SYNC | CTR_FLAG_NOSYNC)
 
 /* Define flags for options without argument (e.g. 'nosync') */
 #define CTR_FLAG_OPTIONS_NO_ARGS    (CTR_FLAGS_ANY_SYNC | \
                      CTR_FLAG_RAID10_USE_NEAR_SETS)
 
 /* Define flags for options with one argument (e.g. 'delta_disks +2') */
 #define CTR_FLAG_OPTIONS_ONE_ARG (CTR_FLAG_REBUILD | \
                   CTR_FLAG_WRITE_MOSTLY | \
                   CTR_FLAG_DAEMON_SLEEP | \
                   CTR_FLAG_MIN_RECOVERY_RATE | \
                   CTR_FLAG_MAX_RECOVERY_RATE | \
                   CTR_FLAG_MAX_WRITE_BEHIND | \
                   CTR_FLAG_STRIPE_CACHE | \
                   CTR_FLAG_REGION_SIZE | \
                   CTR_FLAG_RAID10_COPIES | \
                   CTR_FLAG_RAID10_FORMAT | \
                   CTR_FLAG_DELTA_DISKS | \
                   CTR_FLAG_DATA_OFFSET | \
                   CTR_FLAG_JOURNAL_DEV | \
                   CTR_FLAG_JOURNAL_MODE)
 
 /* Valid options definitions per raid level... */
 
 /* "raid0" does only accept data offset */
 #define RAID0_VALID_FLAGS   (CTR_FLAG_DATA_OFFSET)
 
 /* "raid1" does not accept stripe cache, data offset, delta_disks or any raid10 options */
 #define RAID1_VALID_FLAGS   (CTR_FLAGS_ANY_SYNC | \
                  CTR_FLAG_REBUILD | \
                  CTR_FLAG_WRITE_MOSTLY | \
                  CTR_FLAG_DAEMON_SLEEP | \
                  CTR_FLAG_MIN_RECOVERY_RATE | \
                  CTR_FLAG_MAX_RECOVERY_RATE | \
                  CTR_FLAG_MAX_WRITE_BEHIND | \
                  CTR_FLAG_REGION_SIZE | \
                  CTR_FLAG_DELTA_DISKS | \
                  CTR_FLAG_DATA_OFFSET)
 
 /* "raid10" does not accept any raid1 or stripe cache options */
 #define RAID10_VALID_FLAGS  (CTR_FLAGS_ANY_SYNC | \
                  CTR_FLAG_REBUILD | \
                  CTR_FLAG_DAEMON_SLEEP | \
                  CTR_FLAG_MIN_RECOVERY_RATE | \
                  CTR_FLAG_MAX_RECOVERY_RATE | \
                  CTR_FLAG_REGION_SIZE | \
                  CTR_FLAG_RAID10_COPIES | \
                  CTR_FLAG_RAID10_FORMAT | \
                  CTR_FLAG_DELTA_DISKS | \
                  CTR_FLAG_DATA_OFFSET | \
                  CTR_FLAG_RAID10_USE_NEAR_SETS)
 
 /*
  * "raid4/5/6" do not accept any raid1 or raid10 specific options
  *
  * "raid6" does not accept "nosync", because it is not guaranteed
  * that both parity and q-syndrome are being written properly with
  * any writes
  */
 #define RAID45_VALID_FLAGS  (CTR_FLAGS_ANY_SYNC | \
                  CTR_FLAG_REBUILD | \
                  CTR_FLAG_DAEMON_SLEEP | \
                  CTR_FLAG_MIN_RECOVERY_RATE | \
                  CTR_FLAG_MAX_RECOVERY_RATE | \
                  CTR_FLAG_STRIPE_CACHE | \
                  CTR_FLAG_REGION_SIZE | \
                  CTR_FLAG_DELTA_DISKS | \
                  CTR_FLAG_DATA_OFFSET | \
                  CTR_FLAG_JOURNAL_DEV | \
                  CTR_FLAG_JOURNAL_MODE)
 
 #define RAID6_VALID_FLAGS   (CTR_FLAG_SYNC | \
                  CTR_FLAG_REBUILD | \
                  CTR_FLAG_DAEMON_SLEEP | \
                  CTR_FLAG_MIN_RECOVERY_RATE | \
                  CTR_FLAG_MAX_RECOVERY_RATE | \
                  CTR_FLAG_STRIPE_CACHE | \
                  CTR_FLAG_REGION_SIZE | \
                  CTR_FLAG_DELTA_DISKS | \
                  CTR_FLAG_DATA_OFFSET | \
                  CTR_FLAG_JOURNAL_DEV | \
                  CTR_FLAG_JOURNAL_MODE)
 /* ...valid options definitions per raid level */
 
 /*
  * Flags for rs->runtime_flags field
  * (RT_FLAG prefix meaning "runtime flag")
  *
  * These are all internal and used to define runtime state,
  * e.g. to prevent another resume from preresume processing
  * the raid set all over again.
  */
 #define RT_FLAG_RS_PRERESUMED       0
 #define RT_FLAG_RS_RESUMED      1
 #define RT_FLAG_RS_BITMAP_LOADED    2
 #define RT_FLAG_UPDATE_SBS      3
 #define RT_FLAG_RESHAPE_RS      4
 #define RT_FLAG_RS_SUSPENDED        5
 #define RT_FLAG_RS_IN_SYNC      6
 #define RT_FLAG_RS_RESYNCING        7
 #define RT_FLAG_RS_GROW         8
 
 /* Array elements of 64 bit needed for rebuild/failed disk bits */
 #define DISKS_ARRAY_ELEMS ((MAX_RAID_DEVICES + (sizeof(uint64_t) * 8 - 1)) / sizeof(uint64_t) / 8)
 
 /*
  * raid set level, layout and chunk sectors backup/restore
  */
 struct rs_layout {
     int new_level;
     int new_layout;
     int new_chunk_sectors;
 };
 
 struct raid_set {
     struct dm_target *ti;
 
     uint32_t stripe_cache_entries;
     unsigned long ctr_flags;
     unsigned long runtime_flags;
 
     uint64_t rebuild_disks[DISKS_ARRAY_ELEMS];
 
     int raid_disks;
     int delta_disks;
     int data_offset;
     int raid10_copies;
     int requested_bitmap_chunk_sectors;
 
     struct mddev md;
     struct raid_type *raid_type;
 
     sector_t array_sectors;
     sector_t dev_sectors;
 
     /* Optional raid4/5/6 journal device */
     struct journal_dev {
         struct dm_dev *dev;
         struct md_rdev rdev;
         int mode;
     } journal_dev;
 
     struct raid_dev dev[];
 };
 
 static void rs_config_backup(struct raid_set *rs, struct rs_layout *l)
 {
     struct mddev *mddev = &rs->md;
 
     l->new_level = mddev->new_level;
     l->new_layout = mddev->new_layout;
     l->new_chunk_sectors = mddev->new_chunk_sectors;
 }
 
 static void rs_config_restore(struct raid_set *rs, struct rs_layout *l)
 {
     struct mddev *mddev = &rs->md;
 
     mddev->new_level = l->new_level;
     mddev->new_layout = l->new_layout;
     mddev->new_chunk_sectors = l->new_chunk_sectors;
 }
 
 /* raid10 algorithms (i.e. formats) */
 #define ALGORITHM_RAID10_DEFAULT    0
 #define ALGORITHM_RAID10_NEAR       1
 #define ALGORITHM_RAID10_OFFSET     2
 #define ALGORITHM_RAID10_FAR        3
 
 /* Supported raid types and properties. */
 static struct raid_type {
     const char *name;       /* RAID algorithm. */
     const char *descr;      /* Descriptor text for logging. */
     const unsigned int parity_devs; /* # of parity devices. */
     const unsigned int minimal_devs;/* minimal # of devices in set. */
     const unsigned int level;   /* RAID level. */
     const unsigned int algorithm;   /* RAID algorithm. */
 } raid_types[] = {
     {"raid0",     "raid0 (striping)",               0, 2, 0,  0 /* NONE */},
     {"raid1",     "raid1 (mirroring)",              0, 2, 1,  0 /* NONE */},
     {"raid10_far",    "raid10 far (striped mirrors)",       0, 2, 10, ALGORITHM_RAID10_FAR},
     {"raid10_offset", "raid10 offset (striped mirrors)",        0, 2, 10, ALGORITHM_RAID10_OFFSET},
     {"raid10_near",   "raid10 near (striped mirrors)",      0, 2, 10, ALGORITHM_RAID10_NEAR},
     {"raid10",    "raid10 (striped mirrors)",           0, 2, 10, ALGORITHM_RAID10_DEFAULT},
     {"raid4",     "raid4 (dedicated first parity disk)",    1, 2, 5,  ALGORITHM_PARITY_0}, /* raid4 layout = raid5_0 */
     {"raid5_n",   "raid5 (dedicated last parity disk)",     1, 2, 5,  ALGORITHM_PARITY_N},
     {"raid5_ls",      "raid5 (left symmetric)",         1, 2, 5,  ALGORITHM_LEFT_SYMMETRIC},
     {"raid5_rs",      "raid5 (right symmetric)",            1, 2, 5,  ALGORITHM_RIGHT_SYMMETRIC},
     {"raid5_la",      "raid5 (left asymmetric)",            1, 2, 5,  ALGORITHM_LEFT_ASYMMETRIC},
     {"raid5_ra",      "raid5 (right asymmetric)",           1, 2, 5,  ALGORITHM_RIGHT_ASYMMETRIC},
     {"raid6_zr",      "raid6 (zero restart)",           2, 4, 6,  ALGORITHM_ROTATING_ZERO_RESTART},
     {"raid6_nr",      "raid6 (N restart)",              2, 4, 6,  ALGORITHM_ROTATING_N_RESTART},
     {"raid6_nc",      "raid6 (N continue)",             2, 4, 6,  ALGORITHM_ROTATING_N_CONTINUE},
     {"raid6_n_6",     "raid6 (dedicated parity/Q n/6)",     2, 4, 6,  ALGORITHM_PARITY_N_6},
     {"raid6_ls_6",    "raid6 (left symmetric dedicated Q 6)",   2, 4, 6,  ALGORITHM_LEFT_SYMMETRIC_6},
     {"raid6_rs_6",    "raid6 (right symmetric dedicated Q 6)",  2, 4, 6,  ALGORITHM_RIGHT_SYMMETRIC_6},
     {"raid6_la_6",    "raid6 (left asymmetric dedicated Q 6)",  2, 4, 6,  ALGORITHM_LEFT_ASYMMETRIC_6},
     {"raid6_ra_6",    "raid6 (right asymmetric dedicated Q 6)", 2, 4, 6,  ALGORITHM_RIGHT_ASYMMETRIC_6}
 };
 
 /* True, if @v is in inclusive range [@min, @max] */
 static bool __within_range(long v, long min, long max)
 {
     return v >= min && v <= max;
 }
 
 /* All table line arguments are defined here */
 static struct arg_name_flag {
     const unsigned long flag;
     const char *name;
 } __arg_name_flags[] = {
     { CTR_FLAG_SYNC, "sync"},
     { CTR_FLAG_NOSYNC, "nosync"},
     { CTR_FLAG_REBUILD, "rebuild"},
     { CTR_FLAG_DAEMON_SLEEP, "daemon_sleep"},
     { CTR_FLAG_MIN_RECOVERY_RATE, "min_recovery_rate"},
     { CTR_FLAG_MAX_RECOVERY_RATE, "max_recovery_rate"},
     { CTR_FLAG_MAX_WRITE_BEHIND, "max_write_behind"},
     { CTR_FLAG_WRITE_MOSTLY, "write_mostly"},
     { CTR_FLAG_STRIPE_CACHE, "stripe_cache"},
     { CTR_FLAG_REGION_SIZE, "region_size"},
     { CTR_FLAG_RAID10_COPIES, "raid10_copies"},
     { CTR_FLAG_RAID10_FORMAT, "raid10_format"},
     { CTR_FLAG_DATA_OFFSET, "data_offset"},
     { CTR_FLAG_DELTA_DISKS, "delta_disks"},
     { CTR_FLAG_RAID10_USE_NEAR_SETS, "raid10_use_near_sets"},
     { CTR_FLAG_JOURNAL_DEV, "journal_dev" },
     { CTR_FLAG_JOURNAL_MODE, "journal_mode" },
 };
 
 /* Return argument name string for given @flag */
 static const char *dm_raid_arg_name_by_flag(const uint32_t flag)
 {
     if (hweight32(flag) == 1) {
         struct arg_name_flag *anf = __arg_name_flags + ARRAY_SIZE(__arg_name_flags);
 
         while (anf-- > __arg_name_flags)
             if (flag & anf->flag)
                 return anf->name;
 
     } else
         DMERR("%s called with more than one flag!", __func__);
 
     return NULL;
 }
 
 /* Define correlation of raid456 journal cache modes and dm-raid target line parameters */
 static struct {
     const int mode;
     const char *param;
 } _raid456_journal_mode[] = {
     { R5C_JOURNAL_MODE_WRITE_THROUGH , "writethrough" },
     { R5C_JOURNAL_MODE_WRITE_BACK    , "writeback" }
 };
 
 /* Return MD raid4/5/6 journal mode for dm @journal_mode one */
 static int dm_raid_journal_mode_to_md(const char *mode)
 {
     int m = ARRAY_SIZE(_raid456_journal_mode);
 
     while (m--)
         if (!strcasecmp(mode, _raid456_journal_mode[m].param))
             return _raid456_journal_mode[m].mode;
 
     return -EINVAL;
 }
 
 /* Return dm-raid raid4/5/6 journal mode string for @mode */
 static const char *md_journal_mode_to_dm_raid(const int mode)
 {
     int m = ARRAY_SIZE(_raid456_journal_mode);
 
     while (m--)
         if (mode == _raid456_journal_mode[m].mode)
             return _raid456_journal_mode[m].param;
 
     return "unknown";
 }
 
 /*
  * Bool helpers to test for various raid levels of a raid set.
  * It's level as reported by the superblock rather than
  * the requested raid_type passed to the constructor.
  */
 /* Return true, if raid set in @rs is raid0 */
 static bool rs_is_raid0(struct raid_set *rs)
 {
     return !rs->md.level;
 }
 
 /* Return true, if raid set in @rs is raid1 */
 static bool rs_is_raid1(struct raid_set *rs)
 {
     return rs->md.level == 1;
 }
 
 /* Return true, if raid set in @rs is raid10 */
 static bool rs_is_raid10(struct raid_set *rs)
 {
     return rs->md.level == 10;
 }
 
 /* Return true, if raid set in @rs is level 6 */
 static bool rs_is_raid6(struct raid_set *rs)
 {
     return rs->md.level == 6;
 }
 
 /* Return true, if raid set in @rs is level 4, 5 or 6 */
 static bool rs_is_raid456(struct raid_set *rs)
 {
     return __within_range(rs->md.level, 4, 6);
 }
 
 /* Return true, if raid set in @rs is reshapable */
 static bool __is_raid10_far(int layout);
 static bool rs_is_reshapable(struct raid_set *rs)
 {
     return rs_is_raid456(rs) ||
            (rs_is_raid10(rs) && !__is_raid10_far(rs->md.new_layout));
 }
 
 /* Return true, if raid set in @rs is recovering */
 static bool rs_is_recovering(struct raid_set *rs)
 {
     return rs->md.recovery_cp < rs->md.dev_sectors;
 }
 
 /* Return true, if raid set in @rs is reshaping */
 static bool rs_is_reshaping(struct raid_set *rs)
 {
     return rs->md.reshape_position != MaxSector;
 }
 
 /*
  * bool helpers to test for various raid levels of a raid type @rt
  */
 
 /* Return true, if raid type in @rt is raid0 */
 static bool rt_is_raid0(struct raid_type *rt)
 {
     return !rt->level;
 }
 
 /* Return true, if raid type in @rt is raid1 */
 static bool rt_is_raid1(struct raid_type *rt)
 {
     return rt->level == 1;
 }
 
 /* Return true, if raid type in @rt is raid10 */
 static bool rt_is_raid10(struct raid_type *rt)
 {
     return rt->level == 10;
 }
 
 /* Return true, if raid type in @rt is raid4/5 */
 static bool rt_is_raid45(struct raid_type *rt)
 {
     return __within_range(rt->level, 4, 5);
 }
 
 /* Return true, if raid type in @rt is raid6 */
 static bool rt_is_raid6(struct raid_type *rt)
 {
     return rt->level == 6;
 }
 
 /* Return true, if raid type in @rt is raid4/5/6 */
 static bool rt_is_raid456(struct raid_type *rt)
 {
     return __within_range(rt->level, 4, 6);
 }
 /* END: raid level bools */
 
 /* Return valid ctr flags for the raid level of @rs */
 static unsigned long __valid_flags(struct raid_set *rs)
 {
     if (rt_is_raid0(rs->raid_type))
         return RAID0_VALID_FLAGS;
     else if (rt_is_raid1(rs->raid_type))
         return RAID1_VALID_FLAGS;
     else if (rt_is_raid10(rs->raid_type))
         return RAID10_VALID_FLAGS;
     else if (rt_is_raid45(rs->raid_type))
         return RAID45_VALID_FLAGS;
     else if (rt_is_raid6(rs->raid_type))
         return RAID6_VALID_FLAGS;
 
     return 0;
 }
 
 /*
  * Check for valid flags set on @rs
  *
  * Has to be called after parsing of the ctr flags!
  */
 static int rs_check_for_valid_flags(struct raid_set *rs)
 {
     if (rs->ctr_flags & ~__valid_flags(rs)) {
         rs->ti->error = "Invalid flags combination";
         return -EINVAL;
     }
 
     return 0;
 }
 
 /* MD raid10 bit definitions and helpers */
 #define RAID10_OFFSET           (1 << 16) /* stripes with data copies area adjacent on devices */
 #define RAID10_BROCKEN_USE_FAR_SETS (1 << 17) /* Broken in raid10.c: use sets instead of whole stripe rotation */
 #define RAID10_USE_FAR_SETS     (1 << 18) /* Use sets instead of whole stripe rotation */
 #define RAID10_FAR_COPIES_SHIFT     8     /* raid10 # far copies shift (2nd byte of layout) */
 
 /* Return md raid10 near copies for @layout */
 static unsigned int __raid10_near_copies(int layout)
 {
     return layout & 0xFF;
 }
 
 /* Return md raid10 far copies for @layout */
 static unsigned int __raid10_far_copies(int layout)
 {
     return __raid10_near_copies(layout >> RAID10_FAR_COPIES_SHIFT);
 }
 
 /* Return true if md raid10 offset for @layout */
 static bool __is_raid10_offset(int layout)
 {
     return !!(layout & RAID10_OFFSET);
 }
 
 /* Return true if md raid10 near for @layout */
 static bool __is_raid10_near(int layout)
 {
     return !__is_raid10_offset(layout) && __raid10_near_copies(layout) > 1;
 }
 
 /* Return true if md raid10 far for @layout */
 static bool __is_raid10_far(int layout)
 {
     return !__is_raid10_offset(layout) && __raid10_far_copies(layout) > 1;
 }
 
 /* Return md raid10 layout string for @layout */
 static const char *raid10_md_layout_to_format(int layout)
 {
     /*
      * Bit 16 stands for "offset"
      * (i.e. adjacent stripes hold copies)
      *
      * Refer to MD's raid10.c for details
      */
     if (__is_raid10_offset(layout))
         return "offset";
 
     if (__raid10_near_copies(layout) > 1)
         return "near";
 
     if (__raid10_far_copies(layout) > 1)
         return "far";
 
     return "unknown";
 }
 
 /* Return md raid10 algorithm for @name */
 static int raid10_name_to_format(const char *name)
 {
     if (!strcasecmp(name, "near"))
         return ALGORITHM_RAID10_NEAR;
     else if (!strcasecmp(name, "offset"))
         return ALGORITHM_RAID10_OFFSET;
     else if (!strcasecmp(name, "far"))
         return ALGORITHM_RAID10_FAR;
 
     return -EINVAL;
 }
 
 /* Return md raid10 copies for @layout */
 static unsigned int raid10_md_layout_to_copies(int layout)
 {
     return max(__raid10_near_copies(layout), __raid10_far_copies(layout));
 }
 
 /* Return md raid10 format id for @format string */
 static int raid10_format_to_md_layout(struct raid_set *rs,
                       unsigned int algorithm,
                       unsigned int copies)
 {
     unsigned int n = 1, f = 1, r = 0;
 
     /*
      * MD resilienece flaw:
      *
      * enabling use_far_sets for far/offset formats causes copies
      * to be colocated on the same devs together with their origins!
      *
      * -> disable it for now in the definition above
      */
     if (algorithm == ALGORITHM_RAID10_DEFAULT ||
         algorithm == ALGORITHM_RAID10_NEAR)
         n = copies;
 
     else if (algorithm == ALGORITHM_RAID10_OFFSET) {
         f = copies;
         r = RAID10_OFFSET;
         if (!test_bit(__CTR_FLAG_RAID10_USE_NEAR_SETS, &rs->ctr_flags))
             r |= RAID10_USE_FAR_SETS;
 
     } else if (algorithm == ALGORITHM_RAID10_FAR) {
         f = copies;
         if (!test_bit(__CTR_FLAG_RAID10_USE_NEAR_SETS, &rs->ctr_flags))
             r |= RAID10_USE_FAR_SETS;
 
     } else
         return -EINVAL;
 
     return r | (f << RAID10_FAR_COPIES_SHIFT) | n;
 }
 /* END: MD raid10 bit definitions and helpers */
 
 /* Check for any of the raid10 algorithms */
 static bool __got_raid10(struct raid_type *rtp, const int layout)
 {
     if (rtp->level == 10) {
         switch (rtp->algorithm) {
         case ALGORITHM_RAID10_DEFAULT:
         case ALGORITHM_RAID10_NEAR:
             return __is_raid10_near(layout);
         case ALGORITHM_RAID10_OFFSET:
             return __is_raid10_offset(layout);
         case ALGORITHM_RAID10_FAR:
             return __is_raid10_far(layout);
         default:
             break;
         }
     }
 
     return false;
 }
 
 /* Return raid_type for @name */
 static struct raid_type *get_raid_type(const char *name)
 {
     struct raid_type *rtp = raid_types + ARRAY_SIZE(raid_types);
 
     while (rtp-- > raid_types)
         if (!strcasecmp(rtp->name, name))
             return rtp;
 
     return NULL;
 }
 
 /* Return raid_type for @name based derived from @level and @layout */
 static struct raid_type *get_raid_type_by_ll(const int level, const int layout)
 {
     struct raid_type *rtp = raid_types + ARRAY_SIZE(raid_types);
 
     while (rtp-- > raid_types) {
         /* RAID10 special checks based on @layout flags/properties */
         if (rtp->level == level &&
             (__got_raid10(rtp, layout) || rtp->algorithm == layout))
             return rtp;
     }
 
     return NULL;
 }
 
 /* Adjust rdev sectors */
 static void rs_set_rdev_sectors(struct raid_set *rs)
 {
     struct mddev *mddev = &rs->md;
     struct md_rdev *rdev;
 
     /*
      * raid10 sets rdev->sector to the device size, which
      * is unintended in case of out-of-place reshaping
      */
     rdev_for_each(rdev, mddev)
         if (!test_bit(Journal, &rdev->flags))
             rdev->sectors = mddev->dev_sectors;
 }
 
 /*
  * Change bdev capacity of @rs in case of a disk add/remove reshape
  */
 static void rs_set_capacity(struct raid_set *rs)
 {
     struct gendisk *gendisk = dm_disk(dm_table_get_md(rs->ti->table));
 
     set_capacity_and_notify(gendisk, rs->md.array_sectors);
 }
 
 /*
  * Set the mddev properties in @rs to the current
  * ones retrieved from the freshest superblock
  */
 static void rs_set_cur(struct raid_set *rs)
 {
     struct mddev *mddev = &rs->md;
 
     mddev->new_level = mddev->level;
     mddev->new_layout = mddev->layout;
     mddev->new_chunk_sectors = mddev->chunk_sectors;
 }
 
 /*
  * Set the mddev properties in @rs to the new
  * ones requested by the ctr
  */
 static void rs_set_new(struct raid_set *rs)
 {
     struct mddev *mddev = &rs->md;
 
     mddev->level = mddev->new_level;
     mddev->layout = mddev->new_layout;
     mddev->chunk_sectors = mddev->new_chunk_sectors;
     mddev->raid_disks = rs->raid_disks;
     mddev->delta_disks = 0;
 }
 
 static struct raid_set *raid_set_alloc(struct dm_target *ti, struct raid_type *raid_type,
                        unsigned int raid_devs)
 {
     unsigned int i;
     struct raid_set *rs;
 
     if (raid_devs <= raid_type->parity_devs) {
         ti->error = "Insufficient number of devices";
         return ERR_PTR(-EINVAL);
     }
 
     rs = kzalloc(struct_size(rs, dev, raid_devs), GFP_KERNEL);
     if (!rs) {
         ti->error = "Cannot allocate raid context";
         return ERR_PTR(-ENOMEM);
     }
 
     mddev_init(&rs->md);
 
     rs->raid_disks = raid_devs;
     rs->delta_disks = 0;
 
     rs->ti = ti;
     rs->raid_type = raid_type;
     rs->stripe_cache_entries = 256;
     rs->md.raid_disks = raid_devs;
     rs->md.level = raid_type->level;
     rs->md.new_level = rs->md.level;
     rs->md.layout = raid_type->algorithm;
     rs->md.new_layout = rs->md.layout;
     rs->md.delta_disks = 0;
     rs->md.recovery_cp = MaxSector;
 
     for (i = 0; i < raid_devs; i++)
         md_rdev_init(&rs->dev[i].rdev);
 
     /*
      * Remaining items to be initialized by further RAID params:
      *  rs->md.persistent
      *  rs->md.external
      *  rs->md.chunk_sectors
      *  rs->md.new_chunk_sectors
      *  rs->md.dev_sectors
      */
 
     return rs;
 }
 
 /* Free all @rs allocations */
 static void raid_set_free(struct raid_set *rs)
 {
     int i;
 
     if (rs->journal_dev.dev) {
         md_rdev_clear(&rs->journal_dev.rdev);
         dm_put_device(rs->ti, rs->journal_dev.dev);
     }
 
     for (i = 0; i < rs->raid_disks; i++) {
         if (rs->dev[i].meta_dev)
             dm_put_device(rs->ti, rs->dev[i].meta_dev);
         md_rdev_clear(&rs->dev[i].rdev);
         if (rs->dev[i].data_dev)
             dm_put_device(rs->ti, rs->dev[i].data_dev);
     }
 
     kfree(rs);
 }
 
 /*
  * For every device we have two words
  *  <meta_dev>: meta device name or '-' if missing
  *  <data_dev>: data device name or '-' if missing
  *
  * The following are permitted:
  *    - -
  *    - <data_dev>
  *    <meta_dev> <data_dev>
  *
  * The following is not allowed:
  *    <meta_dev> -
  *
  * This code parses those words.  If there is a failure,
  * the caller must use raid_set_free() to unwind the operations.
  */
 static int parse_dev_params(struct raid_set *rs, struct dm_arg_set *as)
 {
     int i;
     int rebuild = 0;
     int metadata_available = 0;
     int r = 0;
     const char *arg;
 
     /* Put off the number of raid devices argument to get to dev pairs */
     arg = dm_shift_arg(as);
     if (!arg)
         return -EINVAL;
 
     for (i = 0; i < rs->raid_disks; i++) {
         rs->dev[i].rdev.raid_disk = i;
 
         rs->dev[i].meta_dev = NULL;
         rs->dev[i].data_dev = NULL;
 
         /*
          * There are no offsets initially.
          * Out of place reshape will set them accordingly.
          */
         rs->dev[i].rdev.data_offset = 0;
         rs->dev[i].rdev.new_data_offset = 0;
         rs->dev[i].rdev.mddev = &rs->md;
 
         arg = dm_shift_arg(as);
         if (!arg)
             return -EINVAL;
 
         if (strcmp(arg, "-")) {
             r = dm_get_device(rs->ti, arg, dm_table_get_mode(rs->ti->table),
                       &rs->dev[i].meta_dev);
             if (r) {
                 rs->ti->error = "RAID metadata device lookup failure";
                 return r;
             }
 
             rs->dev[i].rdev.sb_page = alloc_page(GFP_KERNEL);
             if (!rs->dev[i].rdev.sb_page) {
                 rs->ti->error = "Failed to allocate superblock page";
                 return -ENOMEM;
             }
         }
 
         arg = dm_shift_arg(as);
         if (!arg)
             return -EINVAL;
 
         if (!strcmp(arg, "-")) {
             if (!test_bit(In_sync, &rs->dev[i].rdev.flags) &&
                 (!rs->dev[i].rdev.recovery_offset)) {
                 rs->ti->error = "Drive designated for rebuild not specified";
                 return -EINVAL;
             }
 
             if (rs->dev[i].meta_dev) {
                 rs->ti->error = "No data device supplied with metadata device";
                 return -EINVAL;
             }
 
             continue;
         }
 
         r = dm_get_device(rs->ti, arg, dm_table_get_mode(rs->ti->table),
                   &rs->dev[i].data_dev);
         if (r) {
             rs->ti->error = "RAID device lookup failure";
             return r;
         }
 
         if (rs->dev[i].meta_dev) {
             metadata_available = 1;
             rs->dev[i].rdev.meta_bdev = rs->dev[i].meta_dev->bdev;
         }
         rs->dev[i].rdev.bdev = rs->dev[i].data_dev->bdev;
         list_add_tail(&rs->dev[i].rdev.same_set, &rs->md.disks);
         if (!test_bit(In_sync, &rs->dev[i].rdev.flags))
             rebuild++;
     }
 
     if (rs->journal_dev.dev)
         list_add_tail(&rs->journal_dev.rdev.same_set, &rs->md.disks);
 
     if (metadata_available) {
         rs->md.external = 0;
         rs->md.persistent = 1;
         rs->md.major_version = 2;
     } else if (rebuild && !rs->md.recovery_cp) {
         /*
          * Without metadata, we will not be able to tell if the array
          * is in-sync or not - we must assume it is not.  Therefore,
          * it is impossible to rebuild a drive.
          *
          * Even if there is metadata, the on-disk information may
          * indicate that the array is not in-sync and it will then
          * fail at that time.
          *
          * User could specify 'nosync' option if desperate.
          */
         rs->ti->error = "Unable to rebuild drive while array is not in-sync";
         return -EINVAL;
     }
 
     return 0;
 }
 
 /*
  * validate_region_size
  * @rs
  * @region_size:  region size in sectors.  If 0, pick a size (4MiB default).
  *
  * Set rs->md.bitmap_info.chunksize (which really refers to 'region size').
  * Ensure that (ti->len/region_size < 2^21) - required by MD bitmap.
  *
  * Returns: 0 on success, -EINVAL on failure.
  */
 static int validate_region_size(struct raid_set *rs, unsigned long region_size)
 {
     unsigned long min_region_size = rs->ti->len / (1 << 21);
 
     if (rs_is_raid0(rs))
         return 0;
 
     if (!region_size) {
         /*
          * Choose a reasonable default.  All figures in sectors.
          */
         if (min_region_size > (1 << 13)) {
             /* If not a power of 2, make it the next power of 2 */
             region_size = roundup_pow_of_two(min_region_size);
             DMINFO("Choosing default region size of %lu sectors",
                    region_size);
         } else {
             DMINFO("Choosing default region size of 4MiB");
             region_size = 1 << 13; /* sectors */
         }
     } else {
         /*
          * Validate user-supplied value.
          */
         if (region_size > rs->ti->len) {
             rs->ti->error = "Supplied region size is too large";
             return -EINVAL;
         }
 
         if (region_size < min_region_size) {
             DMERR("Supplied region_size (%lu sectors) below minimum (%lu)",
                   region_size, min_region_size);
             rs->ti->error = "Supplied region size is too small";
             return -EINVAL;
         }
 
         if (!is_power_of_2(region_size)) {
             rs->ti->error = "Region size is not a power of 2";
             return -EINVAL;
         }
 
         if (region_size < rs->md.chunk_sectors) {
             rs->ti->error = "Region size is smaller than the chunk size";
             return -EINVAL;
         }
     }
 
     /*
      * Convert sectors to bytes.
      */
     rs->md.bitmap_info.chunksize = to_bytes(region_size);
 
     return 0;
 }
 
 /*
  * validate_raid_redundancy
  * @rs
  *
  * Determine if there are enough devices in the array that haven't
  * failed (or are being rebuilt) to form a usable array.
  *
  * Returns: 0 on success, -EINVAL on failure.
  */
 static int validate_raid_redundancy(struct raid_set *rs)
 {
     unsigned int i, rebuild_cnt = 0;
     unsigned int rebuilds_per_group = 0, copies, raid_disks;
     unsigned int group_size, last_group_start;
 
     for (i = 0; i < rs->raid_disks; i++)
         if (!test_bit(FirstUse, &rs->dev[i].rdev.flags) &&
             ((!test_bit(In_sync, &rs->dev[i].rdev.flags) ||
               !rs->dev[i].rdev.sb_page)))
             rebuild_cnt++;
 
     switch (rs->md.level) {
     case 0:
         break;
     case 1:
         if (rebuild_cnt >= rs->md.raid_disks)
             goto too_many;
         break;
     case 4:
     case 5:
     case 6:
         if (rebuild_cnt > rs->raid_type->parity_devs)
             goto too_many;
         break;
     case 10:
         copies = raid10_md_layout_to_copies(rs->md.new_layout);
         if (copies < 2) {
             DMERR("Bogus raid10 data copies < 2!");
             return -EINVAL;
         }
 
         if (rebuild_cnt < copies)
             break;
 
         /*
          * It is possible to have a higher rebuild count for RAID10,
          * as long as the failed devices occur in different mirror
          * groups (i.e. different stripes).
          *
          * When checking "near" format, make sure no adjacent devices
          * have failed beyond what can be handled.  In addition to the
          * simple case where the number of devices is a multiple of the
          * number of copies, we must also handle cases where the number
          * of devices is not a multiple of the number of copies.
          * E.g.    dev1 dev2 dev3 dev4 dev5
          *      A    A    B    B    C
          *      C    D    D    E    E
          */
         raid_disks = min(rs->raid_disks, rs->md.raid_disks);
         if (__is_raid10_near(rs->md.new_layout)) {
             for (i = 0; i < raid_disks; i++) {
                 if (!(i % copies))
                     rebuilds_per_group = 0;
                 if ((!rs->dev[i].rdev.sb_page ||
                     !test_bit(In_sync, &rs->dev[i].rdev.flags)) &&
                     (++rebuilds_per_group >= copies))
                     goto too_many;
             }
             break;
         }
 
         /*
          * When checking "far" and "offset" formats, we need to ensure
          * that the device that holds its copy is not also dead or
          * being rebuilt.  (Note that "far" and "offset" formats only
          * support two copies right now.  These formats also only ever
          * use the 'use_far_sets' variant.)
          *
          * This check is somewhat complicated by the need to account
          * for arrays that are not a multiple of (far) copies.  This
          * results in the need to treat the last (potentially larger)
          * set differently.
          */
         group_size = (raid_disks / copies);
         last_group_start = (raid_disks / group_size) - 1;
         last_group_start *= group_size;
         for (i = 0; i < raid_disks; i++) {
             if (!(i % copies) && !(i > last_group_start))
                 rebuilds_per_group = 0;
             if ((!rs->dev[i].rdev.sb_page ||
                  !test_bit(In_sync, &rs->dev[i].rdev.flags)) &&
                 (++rebuilds_per_group >= copies))
                     goto too_many;
         }
         break;
     default:
         if (rebuild_cnt)
             return -EINVAL;
     }
 
     return 0;
 
 too_many:
     return -EINVAL;
 }
 
 /*
  * Possible arguments are...
  *  <chunk_size> [optional_args]
  *
  * Argument definitions
  *    <chunk_size>          The number of sectors per disk that
  *                  will form the "stripe"
  *    [[no]sync]            Force or prevent recovery of the
  *                  entire array
  *    [rebuild <idx>]           Rebuild the drive indicated by the index
  *    [daemon_sleep <ms>]       Time between bitmap daemon work to
  *                  clear bits
  *    [min_recovery_rate <kB/sec/disk>] Throttle RAID initialization
  *    [max_recovery_rate <kB/sec/disk>] Throttle RAID initialization
  *    [write_mostly <idx>]      Indicate a write mostly drive via index
  *    [max_write_behind <sectors>]  See '-write-behind=' (man mdadm)
  *    [stripe_cache <sectors>]      Stripe cache size for higher RAIDs
  *    [region_size <sectors>]       Defines granularity of bitmap
  *    [journal_dev <dev>]       raid4/5/6 journaling deviice
  *                      (i.e. write hole closing log)
  *
  * RAID10-only options:
  *    [raid10_copies <# copies>]    Number of copies.  (Default: 2)
  *    [raid10_format <near|far|offset>] Layout algorithm.  (Default: near)
  */
 static int parse_raid_params(struct raid_set *rs, struct dm_arg_set *as,
                  unsigned int num_raid_params)
 {
     int value, raid10_format = ALGORITHM_RAID10_DEFAULT;
     unsigned int raid10_copies = 2;
     unsigned int i, write_mostly = 0;
     unsigned int region_size = 0;
     sector_t max_io_len;
     const char *arg, *key;
     struct raid_dev *rd;
     struct raid_type *rt = rs->raid_type;
 
     arg = dm_shift_arg(as);
     num_raid_params--; /* Account for chunk_size argument */
 
     if (kstrtoint(arg, 10, &value) < 0) {
         rs->ti->error = "Bad numerical argument given for chunk_size";
         return -EINVAL;
     }
 
     /*
      * First, parse the in-order required arguments
      * "chunk_size" is the only argument of this type.
      */
     if (rt_is_raid1(rt)) {
         if (value)
             DMERR("Ignoring chunk size parameter for RAID 1");
         value = 0;
     } else if (!is_power_of_2(value)) {
         rs->ti->error = "Chunk size must be a power of 2";
         return -EINVAL;
     } else if (value < 8) {
         rs->ti->error = "Chunk size value is too small";
         return -EINVAL;
     }
 
     rs->md.new_chunk_sectors = rs->md.chunk_sectors = value;
 
     /*
      * We set each individual device as In_sync with a completed
      * 'recovery_offset'.  If there has been a device failure or
      * replacement then one of the following cases applies:
      *
      *   1) User specifies 'rebuild'.
      *  - Device is reset when param is read.
      *   2) A new device is supplied.
      *  - No matching superblock found, resets device.
      *   3) Device failure was transient and returns on reload.
      *  - Failure noticed, resets device for bitmap replay.
      *   4) Device hadn't completed recovery after previous failure.
      *  - Superblock is read and overrides recovery_offset.
      *
      * What is found in the superblocks of the devices is always
      * authoritative, unless 'rebuild' or '[no]sync' was specified.
      */
     for (i = 0; i < rs->raid_disks; i++) {
         set_bit(In_sync, &rs->dev[i].rdev.flags);
         rs->dev[i].rdev.recovery_offset = MaxSector;
     }
 
     /*
      * Second, parse the unordered optional arguments
      */
     for (i = 0; i < num_raid_params; i++) {
         key = dm_shift_arg(as);
         if (!key) {
             rs->ti->error = "Not enough raid parameters given";
             return -EINVAL;
         }
 
         if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_NOSYNC))) {
             if (test_and_set_bit(__CTR_FLAG_NOSYNC, &rs->ctr_flags)) {
                 rs->ti->error = "Only one 'nosync' argument allowed";
                 return -EINVAL;
             }
             continue;
         }
         if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_SYNC))) {
             if (test_and_set_bit(__CTR_FLAG_SYNC, &rs->ctr_flags)) {
                 rs->ti->error = "Only one 'sync' argument allowed";
                 return -EINVAL;
             }
             continue;
         }
         if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_RAID10_USE_NEAR_SETS))) {
             if (test_and_set_bit(__CTR_FLAG_RAID10_USE_NEAR_SETS, &rs->ctr_flags)) {
                 rs->ti->error = "Only one 'raid10_use_new_sets' argument allowed";
                 return -EINVAL;
             }
             continue;
         }
 
         arg = dm_shift_arg(as);
         i++; /* Account for the argument pairs */
         if (!arg) {
             rs->ti->error = "Wrong number of raid parameters given";
             return -EINVAL;
         }
 
         /*
          * Parameters that take a string value are checked here.
          */
         /* "raid10_format {near|offset|far} */
         if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_RAID10_FORMAT))) {
             if (test_and_set_bit(__CTR_FLAG_RAID10_FORMAT, &rs->ctr_flags)) {
                 rs->ti->error = "Only one 'raid10_format' argument pair allowed";
                 return -EINVAL;
             }
             if (!rt_is_raid10(rt)) {
                 rs->ti->error = "'raid10_format' is an invalid parameter for this RAID type";
                 return -EINVAL;
             }
             raid10_format = raid10_name_to_format(arg);
             if (raid10_format < 0) {
                 rs->ti->error = "Invalid 'raid10_format' value given";
                 return raid10_format;
             }
             continue;
         }
 
         /* "journal_dev <dev>" */
         if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_JOURNAL_DEV))) {
             int r;
             struct md_rdev *jdev;
 
             if (test_and_set_bit(__CTR_FLAG_JOURNAL_DEV, &rs->ctr_flags)) {
                 rs->ti->error = "Only one raid4/5/6 set journaling device allowed";
                 return -EINVAL;
             }
             if (!rt_is_raid456(rt)) {
                 rs->ti->error = "'journal_dev' is an invalid parameter for this RAID type";
                 return -EINVAL;
             }
             r = dm_get_device(rs->ti, arg, dm_table_get_mode(rs->ti->table),
                       &rs->journal_dev.dev);
             if (r) {
                 rs->ti->error = "raid4/5/6 journal device lookup failure";
                 return r;
             }
             jdev = &rs->journal_dev.rdev;
             md_rdev_init(jdev);
             jdev->mddev = &rs->md;
             jdev->bdev = rs->journal_dev.dev->bdev;
             jdev->sectors = bdev_nr_sectors(jdev->bdev);
             if (jdev->sectors < MIN_RAID456_JOURNAL_SPACE) {
                 rs->ti->error = "No space for raid4/5/6 journal";
                 return -ENOSPC;
             }
             rs->journal_dev.mode = R5C_JOURNAL_MODE_WRITE_THROUGH;
             set_bit(Journal, &jdev->flags);
             continue;
         }
 
         /* "journal_mode <mode>" ("journal_dev" mandatory!) */
         if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_JOURNAL_MODE))) {
             int r;
 
             if (!test_bit(__CTR_FLAG_JOURNAL_DEV, &rs->ctr_flags)) {
                 rs->ti->error = "raid4/5/6 'journal_mode' is invalid without 'journal_dev'";
                 return -EINVAL;
             }
             if (test_and_set_bit(__CTR_FLAG_JOURNAL_MODE, &rs->ctr_flags)) {
                 rs->ti->error = "Only one raid4/5/6 'journal_mode' argument allowed";
                 return -EINVAL;
             }
             r = dm_raid_journal_mode_to_md(arg);
             if (r < 0) {
                 rs->ti->error = "Invalid 'journal_mode' argument";
                 return r;
             }
             rs->journal_dev.mode = r;
             continue;
         }
 
         /*
          * Parameters with number values from here on.
          */
         if (kstrtoint(arg, 10, &value) < 0) {
             rs->ti->error = "Bad numerical argument given in raid params";
             return -EINVAL;
         }
 
         if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_REBUILD))) {
             /*
              * "rebuild" is being passed in by userspace to provide
              * indexes of replaced devices and to set up additional
              * devices on raid level takeover.
              */
             if (!__within_range(value, 0, rs->raid_disks - 1)) {
                 rs->ti->error = "Invalid rebuild index given";
                 return -EINVAL;
             }
 
             if (test_and_set_bit(value, (void *) rs->rebuild_disks)) {
                 rs->ti->error = "rebuild for this index already given";
                 return -EINVAL;
             }
 
             rd = rs->dev + value;
             clear_bit(In_sync, &rd->rdev.flags);
             clear_bit(Faulty, &rd->rdev.flags);
             rd->rdev.recovery_offset = 0;
             set_bit(__CTR_FLAG_REBUILD, &rs->ctr_flags);
         } else if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_WRITE_MOSTLY))) {
             if (!rt_is_raid1(rt)) {
                 rs->ti->error = "write_mostly option is only valid for RAID1";
                 return -EINVAL;
             }
 
             if (!__within_range(value, 0, rs->md.raid_disks - 1)) {
                 rs->ti->error = "Invalid write_mostly index given";
                 return -EINVAL;
             }
 
             write_mostly++;
             set_bit(WriteMostly, &rs->dev[value].rdev.flags);
             set_bit(__CTR_FLAG_WRITE_MOSTLY, &rs->ctr_flags);
         } else if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_MAX_WRITE_BEHIND))) {
             if (!rt_is_raid1(rt)) {
                 rs->ti->error = "max_write_behind option is only valid for RAID1";
                 return -EINVAL;
             }
 
             if (test_and_set_bit(__CTR_FLAG_MAX_WRITE_BEHIND, &rs->ctr_flags)) {
                 rs->ti->error = "Only one max_write_behind argument pair allowed";
                 return -EINVAL;
             }
 
             /*
              * In device-mapper, we specify things in sectors, but
              * MD records this value in kB
              */
             if (value < 0 || value / 2 > COUNTER_MAX) {
                 rs->ti->error = "Max write-behind limit out of range";
                 return -EINVAL;
             }
 
             rs->md.bitmap_info.max_write_behind = value / 2;
         } else if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_DAEMON_SLEEP))) {
             if (test_and_set_bit(__CTR_FLAG_DAEMON_SLEEP, &rs->ctr_flags)) {
                 rs->ti->error = "Only one daemon_sleep argument pair allowed";
                 return -EINVAL;
             }
             if (value < 0) {
                 rs->ti->error = "daemon sleep period out of range";
                 return -EINVAL;
             }
             rs->md.bitmap_info.daemon_sleep = value;
         } else if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_DATA_OFFSET))) {
             /* Userspace passes new data_offset after having extended the data image LV */
             if (test_and_set_bit(__CTR_FLAG_DATA_OFFSET, &rs->ctr_flags)) {
                 rs->ti->error = "Only one data_offset argument pair allowed";
                 return -EINVAL;
             }
             /* Ensure sensible data offset */
             if (value < 0 ||
                 (value && (value < MIN_FREE_RESHAPE_SPACE || value % to_sector(PAGE_SIZE)))) {
                 rs->ti->error = "Bogus data_offset value";
                 return -EINVAL;
             }
             rs->data_offset = value;
         } else if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_DELTA_DISKS))) {
             /* Define the +/-# of disks to add to/remove from the given raid set */
             if (test_and_set_bit(__CTR_FLAG_DELTA_DISKS, &rs->ctr_flags)) {
                 rs->ti->error = "Only one delta_disks argument pair allowed";
                 return -EINVAL;
             }
             /* Ensure MAX_RAID_DEVICES and raid type minimal_devs! */
             if (!__within_range(abs(value), 1, MAX_RAID_DEVICES - rt->minimal_devs)) {
                 rs->ti->error = "Too many delta_disk requested";
                 return -EINVAL;
             }
 
             rs->delta_disks = value;
         } else if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_STRIPE_CACHE))) {
             if (test_and_set_bit(__CTR_FLAG_STRIPE_CACHE, &rs->ctr_flags)) {
                 rs->ti->error = "Only one stripe_cache argument pair allowed";
                 return -EINVAL;
             }
 
             if (!rt_is_raid456(rt)) {
                 rs->ti->error = "Inappropriate argument: stripe_cache";
                 return -EINVAL;
             }
 
             if (value < 0) {
                 rs->ti->error = "Bogus stripe cache entries value";
                 return -EINVAL;
             }
             rs->stripe_cache_entries = value;
         } else if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_MIN_RECOVERY_RATE))) {
             if (test_and_set_bit(__CTR_FLAG_MIN_RECOVERY_RATE, &rs->ctr_flags)) {
                 rs->ti->error = "Only one min_recovery_rate argument pair allowed";
                 return -EINVAL;
             }
 
             if (value < 0) {
                 rs->ti->error = "min_recovery_rate out of range";
                 return -EINVAL;
             }
             rs->md.sync_speed_min = value;
         } else if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_MAX_RECOVERY_RATE))) {
             if (test_and_set_bit(__CTR_FLAG_MAX_RECOVERY_RATE, &rs->ctr_flags)) {
                 rs->ti->error = "Only one max_recovery_rate argument pair allowed";
                 return -EINVAL;
             }
 
             if (value < 0) {
                 rs->ti->error = "max_recovery_rate out of range";
                 return -EINVAL;
             }
             rs->md.sync_speed_max = value;
         } else if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_REGION_SIZE))) {
             if (test_and_set_bit(__CTR_FLAG_REGION_SIZE, &rs->ctr_flags)) {
                 rs->ti->error = "Only one region_size argument pair allowed";
                 return -EINVAL;
             }
 
             region_size = value;
             rs->requested_bitmap_chunk_sectors = value;
         } else if (!strcasecmp(key, dm_raid_arg_name_by_flag(CTR_FLAG_RAID10_COPIES))) {
             if (test_and_set_bit(__CTR_FLAG_RAID10_COPIES, &rs->ctr_flags)) {
                 rs->ti->error = "Only one raid10_copies argument pair allowed";
                 return -EINVAL;
             }
 
             if (!__within_range(value, 2, rs->md.raid_disks)) {
                 rs->ti->error = "Bad value for 'raid10_copies'";
                 return -EINVAL;
             }
 
             raid10_copies = value;
         } else {
             DMERR("Unable to parse RAID parameter: %s", key);
             rs->ti->error = "Unable to parse RAID parameter";
             return -EINVAL;
         }
     }
 
     if (test_bit(__CTR_FLAG_SYNC, &rs->ctr_flags) &&
         test_bit(__CTR_FLAG_NOSYNC, &rs->ctr_flags)) {
         rs->ti->error = "sync and nosync are mutually exclusive";
         return -EINVAL;
     }
 
     if (test_bit(__CTR_FLAG_REBUILD, &rs->ctr_flags) &&
         (test_bit(__CTR_FLAG_SYNC, &rs->ctr_flags) ||
          test_bit(__CTR_FLAG_NOSYNC, &rs->ctr_flags))) {
         rs->ti->error = "sync/nosync and rebuild are mutually exclusive";
         return -EINVAL;
     }
 
     if (write_mostly >= rs->md.raid_disks) {
         rs->ti->error = "Can't set all raid1 devices to write_mostly";
         return -EINVAL;
     }
 
     if (rs->md.sync_speed_max &&
         rs->md.sync_speed_min > rs->md.sync_speed_max) {
         rs->ti->error = "Bogus recovery rates";
         return -EINVAL;
     }
 
     if (validate_region_size(rs, region_size))
         return -EINVAL;
 
     if (rs->md.chunk_sectors)
         max_io_len = rs->md.chunk_sectors;
     else
         max_io_len = region_size;
 
     if (dm_set_target_max_io_len(rs->ti, max_io_len))
         return -EINVAL;
 
     if (rt_is_raid10(rt)) {
         if (raid10_copies > rs->md.raid_disks) {
             rs->ti->error = "Not enough devices to satisfy specification";
             return -EINVAL;
         }
 
         rs->md.new_layout = raid10_format_to_md_layout(rs, raid10_format, raid10_copies);
         if (rs->md.new_layout < 0) {
             rs->ti->error = "Error getting raid10 format";
             return rs->md.new_layout;
         }
 
         rt = get_raid_type_by_ll(10, rs->md.new_layout);
         if (!rt) {
             rs->ti->error = "Failed to recognize new raid10 layout";
             return -EINVAL;
         }
 
         if ((rt->algorithm == ALGORITHM_RAID10_DEFAULT ||
              rt->algorithm == ALGORITHM_RAID10_NEAR) &&
             test_bit(__CTR_FLAG_RAID10_USE_NEAR_SETS, &rs->ctr_flags)) {
             rs->ti->error = "RAID10 format 'near' and 'raid10_use_near_sets' are incompatible";
             return -EINVAL;
         }
     }
 
     rs->raid10_copies = raid10_copies;
 
     /* Assume there are no metadata devices until the drives are parsed */
     rs->md.persistent = 0;
     rs->md.external = 1;
 
     /* Check, if any invalid ctr arguments have been passed in for the raid level */
     return rs_check_for_valid_flags(rs);
 }
 
 /* Set raid4/5/6 cache size */
 static int rs_set_raid456_stripe_cache(struct raid_set *rs)
 {
     int r;
     struct r5conf *conf;
     struct mddev *mddev = &rs->md;
     uint32_t min_stripes = max(mddev->chunk_sectors, mddev->new_chunk_sectors) / 2;
     uint32_t nr_stripes = rs->stripe_cache_entries;
 
     if (!rt_is_raid456(rs->raid_type)) {
         rs->ti->error = "Inappropriate raid level; cannot change stripe_cache size";
         return -EINVAL;
     }
 
     if (nr_stripes < min_stripes) {
         DMINFO("Adjusting requested %u stripe cache entries to %u to suit stripe size",
                nr_stripes, min_stripes);
         nr_stripes = min_stripes;
     }
 
     conf = mddev->private;
     if (!conf) {
         rs->ti->error = "Cannot change stripe_cache size on inactive RAID set";
         return -EINVAL;
     }
 
     /* Try setting number of stripes in raid456 stripe cache */
     if (conf->min_nr_stripes != nr_stripes) {
         r = raid5_set_cache_size(mddev, nr_stripes);
         if (r) {
             rs->ti->error = "Failed to set raid4/5/6 stripe cache size";
             return r;
         }
 
         DMINFO("%u stripe cache entries", nr_stripes);
     }
 
     return 0;
 }
 
 /* Return # of data stripes as kept in mddev as of @rs (i.e. as of superblock) */
 static unsigned int mddev_data_stripes(struct raid_set *rs)
 {
     return rs->md.raid_disks - rs->raid_type->parity_devs;
 }
 
 /* Return # of data stripes of @rs (i.e. as of ctr) */
 static unsigned int rs_data_stripes(struct raid_set *rs)
 {
     return rs->raid_disks - rs->raid_type->parity_devs;
 }
 
 /*
  * Retrieve rdev->sectors from any valid raid device of @rs
  * to allow userpace to pass in arbitray "- -" device tupples.
  */
 static sector_t __rdev_sectors(struct raid_set *rs)
 {
     int i;
 
     for (i = 0; i < rs->raid_disks; i++) {
         struct md_rdev *rdev = &rs->dev[i].rdev;
 
         if (!test_bit(Journal, &rdev->flags) &&
             rdev->bdev && rdev->sectors)
             return rdev->sectors;
     }
 
     return 0;
 }
 
 /* Check that calculated dev_sectors fits all component devices. */
 static int _check_data_dev_sectors(struct raid_set *rs)
 {
     sector_t ds = ~0;
     struct md_rdev *rdev;
 
     rdev_for_each(rdev, &rs->md)
         if (!test_bit(Journal, &rdev->flags) && rdev->bdev) {
             ds = min(ds, bdev_nr_sectors(rdev->bdev));
             if (ds < rs->md.dev_sectors) {
                 rs->ti->error = "Component device(s) too small";
                 return -EINVAL;
             }
         }
 
     return 0;
 }
 
 /* Calculate the sectors per device and per array used for @rs */
 static int rs_set_dev_and_array_sectors(struct raid_set *rs, sector_t sectors, bool use_mddev)
 {
     int delta_disks;
     unsigned int data_stripes;
     sector_t array_sectors = sectors, dev_sectors = sectors;
     struct mddev *mddev = &rs->md;
 
     if (use_mddev) {
         delta_disks = mddev->delta_disks;
         data_stripes = mddev_data_stripes(rs);
     } else {
         delta_disks = rs->delta_disks;
         data_stripes = rs_data_stripes(rs);
     }
 
     /* Special raid1 case w/o delta_disks support (yet) */
     if (rt_is_raid1(rs->raid_type))
         ;
     else if (rt_is_raid10(rs->raid_type)) {
         if (rs->raid10_copies < 2 ||
             delta_disks < 0) {
             rs->ti->error = "Bogus raid10 data copies or delta disks";
             return -EINVAL;
         }
 
         dev_sectors *= rs->raid10_copies;
         if (sector_div(dev_sectors, data_stripes))
             goto bad;
 
         array_sectors = (data_stripes + delta_disks) * dev_sectors;
         if (sector_div(array_sectors, rs->raid10_copies))
             goto bad;
 
     } else if (sector_div(dev_sectors, data_stripes))
         goto bad;
 
     else
         /* Striped layouts */
         array_sectors = (data_stripes + delta_disks) * dev_sectors;
 
     mddev->array_sectors = array_sectors;
     mddev->dev_sectors = dev_sectors;
     rs_set_rdev_sectors(rs);
 
     return _check_data_dev_sectors(rs);
 bad:
     rs->ti->error = "Target length not divisible by number of data devices";
     return -EINVAL;
 }
 
 /* Setup recovery on @rs */
 static void rs_setup_recovery(struct raid_set *rs, sector_t dev_sectors)
 {
     /* raid0 does not recover */
     if (rs_is_raid0(rs))
         rs->md.recovery_cp = MaxSector;
     /*
      * A raid6 set has to be recovered either
      * completely or for the grown part to
      * ensure proper parity and Q-Syndrome
      */
     else if (rs_is_raid6(rs))
         rs->md.recovery_cp = dev_sectors;
     /*
      * Other raid set types may skip recovery
      * depending on the 'nosync' flag.
      */
     else
         rs->md.recovery_cp = test_bit(__CTR_FLAG_NOSYNC, &rs->ctr_flags)
                      ? MaxSector : dev_sectors;
 }
 
 static void do_table_event(struct work_struct *ws)
 {
     struct raid_set *rs = container_of(ws, struct raid_set, md.event_work);
 
     smp_rmb(); /* Make sure we access most actual mddev properties */
     if (!rs_is_reshaping(rs)) {
         if (rs_is_raid10(rs))
             rs_set_rdev_sectors(rs);
         rs_set_capacity(rs);
     }
     dm_table_event(rs->ti->table);
 }
 
 /*
  * Make sure a valid takover (level switch) is being requested on @rs
  *
  * Conversions of raid sets from one MD personality to another
  * have to conform to restrictions which are enforced here.
  */
 static int rs_check_takeover(struct raid_set *rs)
 {
     struct mddev *mddev = &rs->md;
     unsigned int near_copies;
 
     if (rs->md.degraded) {
         rs->ti->error = "Can't takeover degraded raid set";
         return -EPERM;
     }
 
     if (rs_is_reshaping(rs)) {
         rs->ti->error = "Can't takeover reshaping raid set";
         return -EPERM;
     }
 
     switch (mddev->level) {
     case 0:
         /* raid0 -> raid1/5 with one disk */
         if ((mddev->new_level == 1 || mddev->new_level == 5) &&
             mddev->raid_disks == 1)
             return 0;
 
         /* raid0 -> raid10 */
         if (mddev->new_level == 10 &&
             !(rs->raid_disks % mddev->raid_disks))
             return 0;
 
         /* raid0 with multiple disks -> raid4/5/6 */
         if (__within_range(mddev->new_level, 4, 6) &&
             mddev->new_layout == ALGORITHM_PARITY_N &&
             mddev->raid_disks > 1)
             return 0;
 
         break;
 
     case 10:
         /* Can't takeover raid10_offset! */
         if (__is_raid10_offset(mddev->layout))
             break;
 
         near_copies = __raid10_near_copies(mddev->layout);
 
         /* raid10* -> raid0 */
         if (mddev->new_level == 0) {
             /* Can takeover raid10_near with raid disks divisable by data copies! */
             if (near_copies > 1 &&
                 !(mddev->raid_disks % near_copies)) {
                 mddev->raid_disks /= near_copies;
                 mddev->delta_disks = mddev->raid_disks;
                 return 0;
             }
 
             /* Can takeover raid10_far */
             if (near_copies == 1 &&
                 __raid10_far_copies(mddev->layout) > 1)
                 return 0;
 
             break;
         }
 
         /* raid10_{near,far} -> raid1 */
         if (mddev->new_level == 1 &&
             max(near_copies, __raid10_far_copies(mddev->layout)) == mddev->raid_disks)
             return 0;
 
         /* raid10_{near,far} with 2 disks -> raid4/5 */
         if (__within_range(mddev->new_level, 4, 5) &&
             mddev->raid_disks == 2)
             return 0;
         break;
 
     case 1:
         /* raid1 with 2 disks -> raid4/5 */
         if (__within_range(mddev->new_level, 4, 5) &&
             mddev->raid_disks == 2) {
             mddev->degraded = 1;
             return 0;
         }
 
         /* raid1 -> raid0 */
         if (mddev->new_level == 0 &&
             mddev->raid_disks == 1)
             return 0;
 
         /* raid1 -> raid10 */
         if (mddev->new_level == 10)
             return 0;
         break;
 
     case 4:
         /* raid4 -> raid0 */
         if (mddev->new_level == 0)
             return 0;
 
         /* raid4 -> raid1/5 with 2 disks */
         if ((mddev->new_level == 1 || mddev->new_level == 5) &&
             mddev->raid_disks == 2)
             return 0;
 
         /* raid4 -> raid5/6 with parity N */
         if (__within_range(mddev->new_level, 5, 6) &&
             mddev->layout == ALGORITHM_PARITY_N)
             return 0;
         break;
 
     case 5:
         /* raid5 with parity N -> raid0 */
         if (mddev->new_level == 0 &&
             mddev->layout == ALGORITHM_PARITY_N)
             return 0;
 
         /* raid5 with parity N -> raid4 */
         if (mddev->new_level == 4 &&
             mddev->layout == ALGORITHM_PARITY_N)
             return 0;
 
         /* raid5 with 2 disks -> raid1/4/10 */
         if ((mddev->new_level == 1 || mddev->new_level == 4 || mddev->new_level == 10) &&
             mddev->raid_disks == 2)
             return 0;
 
         /* raid5_* ->  raid6_*_6 with Q-Syndrome N (e.g. raid5_ra -> raid6_ra_6 */
         if (mddev->new_level == 6 &&
             ((mddev->layout == ALGORITHM_PARITY_N && mddev->new_layout == ALGORITHM_PARITY_N) ||
               __within_range(mddev->new_layout, ALGORITHM_LEFT_ASYMMETRIC_6, ALGORITHM_RIGHT_SYMMETRIC_6)))
             return 0;
         break;
 
     case 6:
         /* raid6 with parity N -> raid0 */
         if (mddev->new_level == 0 &&
             mddev->layout == ALGORITHM_PARITY_N)
             return 0;
 
         /* raid6 with parity N -> raid4 */
         if (mddev->new_level == 4 &&
             mddev->layout == ALGORITHM_PARITY_N)
             return 0;
 
         /* raid6_*_n with Q-Syndrome N -> raid5_* */
         if (mddev->new_level == 5 &&
             ((mddev->layout == ALGORITHM_PARITY_N && mddev->new_layout == ALGORITHM_PARITY_N) ||
              __within_range(mddev->new_layout, ALGORITHM_LEFT_ASYMMETRIC, ALGORITHM_RIGHT_SYMMETRIC)))
             return 0;
         break;
 
     default:
         break;
     }
 
     rs->ti->error = "takeover not possible";
     return -EINVAL;
 }
 
 /* True if @rs requested to be taken over */
 static bool rs_takeover_requested(struct raid_set *rs)
 {
     return rs->md.new_level != rs->md.level;
 }
 
 /* True if layout is set to reshape. */
 static bool rs_is_layout_change(struct raid_set *rs, bool use_mddev)
 {
     return (use_mddev ? rs->md.delta_disks : rs->delta_disks) ||
            rs->md.new_layout != rs->md.layout ||
            rs->md.new_chunk_sectors != rs->md.chunk_sectors;
 }
 
 /* True if @rs is requested to reshape by ctr */
 static bool rs_reshape_requested(struct raid_set *rs)
 {
     bool change;
     struct mddev *mddev = &rs->md;
 
     if (rs_takeover_requested(rs))
         return false;
 
     if (rs_is_raid0(rs))
         return false;
 
     change = rs_is_layout_change(rs, false);
 
     /* Historical case to support raid1 reshape without delta disks */
     if (rs_is_raid1(rs)) {
         if (rs->delta_disks)
             return !!rs->delta_disks;
 
         return !change &&
                mddev->raid_disks != rs->raid_disks;
     }
 
     if (rs_is_raid10(rs))
         return change &&
                !__is_raid10_far(mddev->new_layout) &&
                rs->delta_disks >= 0;
 
     return change;
 }
 
 /*  Features */
 #define FEATURE_FLAG_SUPPORTS_V190  0x1 /* Supports extended superblock */
 
 /* State flags for sb->flags */
 #define SB_FLAG_RESHAPE_ACTIVE      0x1
 #define SB_FLAG_RESHAPE_BACKWARDS   0x2
 
 /*
  * This structure is never routinely used by userspace, unlike md superblocks.
  * Devices with this superblock should only ever be accessed via device-mapper.
  */
 #define DM_RAID_MAGIC 0x64526D44
 struct dm_raid_superblock {
     __le32 magic;       /* "DmRd" */
     __le32 compat_features; /* Used to indicate compatible features (like 1.9.0 ondisk metadata extension) */
 
     __le32 num_devices; /* Number of devices in this raid set. (Max 64) */
     __le32 array_position;  /* The position of this drive in the raid set */
 
     __le64 events;      /* Incremented by md when superblock updated */
     __le64 failed_devices;  /* Pre 1.9.0 part of bit field of devices to */
                 /* indicate failures (see extension below) */
 
     /*
      * This offset tracks the progress of the repair or replacement of
      * an individual drive.
      */
     __le64 disk_recovery_offset;
 
     /*
      * This offset tracks the progress of the initial raid set
      * synchronisation/parity calculation.
      */
     __le64 array_resync_offset;
 
     /*
      * raid characteristics
      */
     __le32 level;
     __le32 layout;
     __le32 stripe_sectors;
 
     /********************************************************************
      * BELOW FOLLOW V1.9.0 EXTENSIONS TO THE PRISTINE SUPERBLOCK FORMAT!!!
      *
      * FEATURE_FLAG_SUPPORTS_V190 in the compat_features member indicates that those exist
      */
 
     __le32 flags; /* Flags defining array states for reshaping */
 
     /*
      * This offset tracks the progress of a raid
      * set reshape in order to be able to restart it
      */
     __le64 reshape_position;
 
     /*
      * These define the properties of the array in case of an interrupted reshape
      */
     __le32 new_level;
     __le32 new_layout;
     __le32 new_stripe_sectors;
     __le32 delta_disks;
 
     __le64 array_sectors; /* Array size in sectors */
 
     /*
      * Sector offsets to data on devices (reshaping).
      * Needed to support out of place reshaping, thus
      * not writing over any stripes whilst converting
      * them from old to new layout
      */
     __le64 data_offset;
     __le64 new_data_offset;
 
     __le64 sectors; /* Used device size in sectors */
 
     /*
      * Additonal Bit field of devices indicating failures to support
      * up to 256 devices with the 1.9.0 on-disk metadata format
      */
     __le64 extended_failed_devices[DISKS_ARRAY_ELEMS - 1];
 
     __le32 incompat_features;   /* Used to indicate any incompatible features */
 
     /* Always set rest up to logical block size to 0 when writing (see get_metadata_device() below). */
 } __packed;
 
 /*
  * Check for reshape constraints on raid set @rs:
  *
  * - reshape function non-existent
  * - degraded set
  * - ongoing recovery
  * - ongoing reshape
  *
  * Returns 0 if none or -EPERM if given constraint
  * and error message reference in @errmsg
  */
 static int rs_check_reshape(struct raid_set *rs)
 {
     struct mddev *mddev = &rs->md;
 
     if (!mddev->pers || !mddev->pers->check_reshape)
         rs->ti->error = "Reshape not supported";
     else if (mddev->degraded)
         rs->ti->error = "Can't reshape degraded raid set";
     else if (rs_is_recovering(rs))
         rs->ti->error = "Convert request on recovering raid set prohibited";
     else if (rs_is_reshaping(rs))
         rs->ti->error = "raid set already reshaping!";
     else if (!(rs_is_raid1(rs) || rs_is_raid10(rs) || rs_is_raid456(rs)))
         rs->ti->error = "Reshaping only supported for raid1/4/5/6/10";
     else
         return 0;
 
     return -EPERM;
 }
 
 static int read_disk_sb(struct md_rdev *rdev, int size, bool force_reload)
 {
     BUG_ON(!rdev->sb_page);
 
     if (rdev->sb_loaded && !force_reload)
         return 0;
 
     rdev->sb_loaded = 0;
 
     if (!sync_page_io(rdev, 0, size, rdev->sb_page, REQ_OP_READ, true)) {
         DMERR("Failed to read superblock of device at position %d",
               rdev->raid_disk);
         md_error(rdev->mddev, rdev);
         set_bit(Faulty, &rdev->flags);
         return -EIO;
     }
 
     rdev->sb_loaded = 1;
 
     return 0;
 }
 
 static void sb_retrieve_failed_devices(struct dm_raid_superblock *sb, uint64_t *failed_devices)
 {
     failed_devices[0] = le64_to_cpu(sb->failed_devices);
     memset(failed_devices + 1, 0, sizeof(sb->extended_failed_devices));
 
     if (le32_to_cpu(sb->compat_features) & FEATURE_FLAG_SUPPORTS_V190) {
         int i = ARRAY_SIZE(sb->extended_failed_devices);
 
         while (i--)
             failed_devices[i+1] = le64_to_cpu(sb->extended_failed_devices[i]);
     }
 }
 
 static void sb_update_failed_devices(struct dm_raid_superblock *sb, uint64_t *failed_devices)
 {
     int i = ARRAY_SIZE(sb->extended_failed_devices);
 
     sb->failed_devices = cpu_to_le64(failed_devices[0]);
     while (i--)
         sb->extended_failed_devices[i] = cpu_to_le64(failed_devices[i+1]);
 }
 
 /*
  * Synchronize the superblock members with the raid set properties
  *
  * All superblock data is little endian.
  */
 static void super_sync(struct mddev *mddev, struct md_rdev *rdev)
 {
     bool update_failed_devices = false;
     unsigned int i;
     uint64_t failed_devices[DISKS_ARRAY_ELEMS];
     struct dm_raid_superblock *sb;
     struct raid_set *rs = container_of(mddev, struct raid_set, md);
 
     /* No metadata device, no superblock */
     if (!rdev->meta_bdev)
         return;
 
     BUG_ON(!rdev->sb_page);
 
     sb = page_address(rdev->sb_page);
 
     sb_retrieve_failed_devices(sb, failed_devices);
 
     for (i = 0; i < rs->raid_disks; i++)
         if (!rs->dev[i].data_dev || test_bit(Faulty, &rs->dev[i].rdev.flags)) {
             update_failed_devices = true;
             set_bit(i, (void *) failed_devices);
         }
 
     if (update_failed_devices)
         sb_update_failed_devices(sb, failed_devices);
 
     sb->magic = cpu_to_le32(DM_RAID_MAGIC);
     sb->compat_features = cpu_to_le32(FEATURE_FLAG_SUPPORTS_V190);
 
     sb->num_devices = cpu_to_le32(mddev->raid_disks);
     sb->array_position = cpu_to_le32(rdev->raid_disk);
 
     sb->events = cpu_to_le64(mddev->events);
 
     sb->disk_recovery_offset = cpu_to_le64(rdev->recovery_offset);
     sb->array_resync_offset = cpu_to_le64(mddev->recovery_cp);
 
     sb->level = cpu_to_le32(mddev->level);
     sb->layout = cpu_to_le32(mddev->layout);
     sb->stripe_sectors = cpu_to_le32(mddev->chunk_sectors);
 
     /********************************************************************
      * BELOW FOLLOW V1.9.0 EXTENSIONS TO THE PRISTINE SUPERBLOCK FORMAT!!!
      *
      * FEATURE_FLAG_SUPPORTS_V190 in the compat_features member indicates that those exist
      */
     sb->new_level = cpu_to_le32(mddev->new_level);
     sb->new_layout = cpu_to_le32(mddev->new_layout);
     sb->new_stripe_sectors = cpu_to_le32(mddev->new_chunk_sectors);
 
     sb->delta_disks = cpu_to_le32(mddev->delta_disks);
 
     smp_rmb(); /* Make sure we access most recent reshape position */
     sb->reshape_position = cpu_to_le64(mddev->reshape_position);
     if (le64_to_cpu(sb->reshape_position) != MaxSector) {
         /* Flag ongoing reshape */
         sb->flags |= cpu_to_le32(SB_FLAG_RESHAPE_ACTIVE);
 
         if (mddev->delta_disks < 0 || mddev->reshape_backwards)
             sb->flags |= cpu_to_le32(SB_FLAG_RESHAPE_BACKWARDS);
     } else {
         /* Clear reshape flags */
         sb->flags &= ~(cpu_to_le32(SB_FLAG_RESHAPE_ACTIVE|SB_FLAG_RESHAPE_BACKWARDS));
     }
 
     sb->array_sectors = cpu_to_le64(mddev->array_sectors);
     sb->data_offset = cpu_to_le64(rdev->data_offset);
     sb->new_data_offset = cpu_to_le64(rdev->new_data_offset);
     sb->sectors = cpu_to_le64(rdev->sectors);
     sb->incompat_features = cpu_to_le32(0);
 
     /* Zero out the rest of the payload after the size of the superblock */
     memset(sb + 1, 0, rdev->sb_size - sizeof(*sb));
 }
 
 /*
  * super_load
  *
  * This function creates a superblock if one is not found on the device
  * and will decide which superblock to use if there's a choice.
  *
  * Return: 1 if use rdev, 0 if use refdev, -Exxx otherwise
  */
 static int super_load(struct md_rdev *rdev, struct md_rdev *refdev)
 {
     int r;
     struct dm_raid_superblock *sb;
     struct dm_raid_superblock *refsb;
     uint64_t events_sb, events_refsb;
 
     r = read_disk_sb(rdev, rdev->sb_size, false);
     if (r)
         return r;
 
     sb = page_address(rdev->sb_page);
 
     /*
      * Two cases that we want to write new superblocks and rebuild:
      * 1) New device (no matching magic number)
      * 2) Device specified for rebuild (!In_sync w/ offset == 0)
      */
     if ((sb->magic != cpu_to_le32(DM_RAID_MAGIC)) ||
         (!test_bit(In_sync, &rdev->flags) && !rdev->recovery_offset)) {
         super_sync(rdev->mddev, rdev);
 
         set_bit(FirstUse, &rdev->flags);
         sb->compat_features = cpu_to_le32(FEATURE_FLAG_SUPPORTS_V190);
 
         /* Force writing of superblocks to disk */
         set_bit(MD_SB_CHANGE_DEVS, &rdev->mddev->sb_flags);
 
         /* Any superblock is better than none, choose that if given */
         return refdev ? 0 : 1;
     }
 
     if (!refdev)
         return 1;
 
     events_sb = le64_to_cpu(sb->events);
 
     refsb = page_address(refdev->sb_page);
     events_refsb = le64_to_cpu(refsb->events);
 
     return (events_sb > events_refsb) ? 1 : 0;
 }
 
 static int super_init_validation(struct raid_set *rs, struct md_rdev *rdev)
 {
     int role;
     unsigned int d;
     struct mddev *mddev = &rs->md;
     uint64_t events_sb;
     uint64_t failed_devices[DISKS_ARRAY_ELEMS];
     struct dm_raid_superblock *sb;
     uint32_t new_devs = 0, rebuild_and_new = 0, rebuilds = 0;
     struct md_rdev *r;
     struct dm_raid_superblock *sb2;
 
     sb = page_address(rdev->sb_page);
     events_sb = le64_to_cpu(sb->events);
 
     /*
      * Initialise to 1 if this is a new superblock.
      */
     mddev->events = events_sb ? : 1;
 
     mddev->reshape_position = MaxSector;
 
     mddev->raid_disks = le32_to_cpu(sb->num_devices);
     mddev->level = le32_to_cpu(sb->level);
     mddev->layout = le32_to_cpu(sb->layout);
     mddev->chunk_sectors = le32_to_cpu(sb->stripe_sectors);
 
     /*
      * Reshaping is supported, e.g. reshape_position is valid
      * in superblock and superblock content is authoritative.
      */
     if (le32_to_cpu(sb->compat_features) & FEATURE_FLAG_SUPPORTS_V190) {
         /* Superblock is authoritative wrt given raid set layout! */
         mddev->new_level = le32_to_cpu(sb->new_level);
         mddev->new_layout = le32_to_cpu(sb->new_layout);
         mddev->new_chunk_sectors = le32_to_cpu(sb->new_stripe_sectors);
         mddev->delta_disks = le32_to_cpu(sb->delta_disks);
         mddev->array_sectors = le64_to_cpu(sb->array_sectors);
 
         /* raid was reshaping and got interrupted */
         if (le32_to_cpu(sb->flags) & SB_FLAG_RESHAPE_ACTIVE) {
             if (test_bit(__CTR_FLAG_DELTA_DISKS, &rs->ctr_flags)) {
                 DMERR("Reshape requested but raid set is still reshaping");
                 return -EINVAL;
             }
 
             if (mddev->delta_disks < 0 ||
                 (!mddev->delta_disks && (le32_to_cpu(sb->flags) & SB_FLAG_RESHAPE_BACKWARDS)))
                 mddev->reshape_backwards = 1;
             else
                 mddev->reshape_backwards = 0;
 
             mddev->reshape_position = le64_to_cpu(sb->reshape_position);
             rs->raid_type = get_raid_type_by_ll(mddev->level, mddev->layout);
         }
 
     } else {
         /*
          * No takeover/reshaping, because we don't have the extended v1.9.0 metadata
          */
         struct raid_type *rt_cur = get_raid_type_by_ll(mddev->level, mddev->layout);
         struct raid_type *rt_new = get_raid_type_by_ll(mddev->new_level, mddev->new_layout);
 
         if (rs_takeover_requested(rs)) {
             if (rt_cur && rt_new)
                 DMERR("Takeover raid sets from %s to %s not yet supported by metadata. (raid level change)",
                       rt_cur->name, rt_new->name);
             else
                 DMERR("Takeover raid sets not yet supported by metadata. (raid level change)");
             return -EINVAL;
         } else if (rs_reshape_requested(rs)) {
             DMERR("Reshaping raid sets not yet supported by metadata. (raid layout change keeping level)");
             if (mddev->layout != mddev->new_layout) {
                 if (rt_cur && rt_new)
                     DMERR("  current layout %s vs new layout %s",
                           rt_cur->name, rt_new->name);
                 else
                     DMERR("  current layout 0x%X vs new layout 0x%X",
                           le32_to_cpu(sb->layout), mddev->new_layout);
             }
             if (mddev->chunk_sectors != mddev->new_chunk_sectors)
                 DMERR("  current stripe sectors %u vs new stripe sectors %u",
                       mddev->chunk_sectors, mddev->new_chunk_sectors);
             if (rs->delta_disks)
                 DMERR("  current %u disks vs new %u disks",
                       mddev->raid_disks, mddev->raid_disks + rs->delta_disks);
             if (rs_is_raid10(rs)) {
                 DMERR("  Old layout: %s w/ %u copies",
                       raid10_md_layout_to_format(mddev->layout),
                       raid10_md_layout_to_copies(mddev->layout));
                 DMERR("  New layout: %s w/ %u copies",
                       raid10_md_layout_to_format(mddev->new_layout),
                       raid10_md_layout_to_copies(mddev->new_layout));
             }
             return -EINVAL;
         }
 
         DMINFO("Discovered old metadata format; upgrading to extended metadata format");
     }
 
     if (!test_bit(__CTR_FLAG_NOSYNC, &rs->ctr_flags))
         mddev->recovery_cp = le64_to_cpu(sb->array_resync_offset);
 
     /*
      * During load, we set FirstUse if a new superblock was written.
      * There are two reasons we might not have a superblock:
      * 1) The raid set is brand new - in which case, all of the
      *    devices must have their In_sync bit set.  Also,
      *    recovery_cp must be 0, unless forced.
      * 2) This is a new device being added to an old raid set
      *    and the new device needs to be rebuilt - in which
      *    case the In_sync bit will /not/ be set and
      *    recovery_cp must be MaxSector.
      * 3) This is/are a new device(s) being added to an old
      *    raid set during takeover to a higher raid level
      *    to provide capacity for redundancy or during reshape
      *    to add capacity to grow the raid set.
      */
     d = 0;
     rdev_for_each(r, mddev) {
         if (test_bit(Journal, &rdev->flags))
             continue;
 
         if (test_bit(FirstUse, &r->flags))
             new_devs++;
 
         if (!test_bit(In_sync, &r->flags)) {
             DMINFO("Device %d specified for rebuild; clearing superblock",
                 r->raid_disk);
             rebuilds++;
 
             if (test_bit(FirstUse, &r->flags))
                 rebuild_and_new++;
         }
 
         d++;
     }
 
     if (new_devs == rs->raid_disks || !rebuilds) {
         /* Replace a broken device */
         if (new_devs == rs->raid_disks) {
             DMINFO("Superblocks created for new raid set");
             set_bit(MD_ARRAY_FIRST_USE, &mddev->flags);
         } else if (new_devs != rebuilds &&
                new_devs != rs->delta_disks) {
             DMERR("New device injected into existing raid set without "
                   "'delta_disks' or 'rebuild' parameter specified");
             return -EINVAL;
         }
     } else if (new_devs && new_devs != rebuilds) {
         DMERR("%u 'rebuild' devices cannot be injected into"
               " a raid set with %u other first-time devices",
               rebuilds, new_devs);
         return -EINVAL;
     } else if (rebuilds) {
         if (rebuild_and_new && rebuilds != rebuild_and_new) {
             DMERR("new device%s provided without 'rebuild'",
                   new_devs > 1 ? "s" : "");
             return -EINVAL;
         } else if (!test_bit(__CTR_FLAG_REBUILD, &rs->ctr_flags) && rs_is_recovering(rs)) {
             DMERR("'rebuild' specified while raid set is not in-sync (recovery_cp=%llu)",
                   (unsigned long long) mddev->recovery_cp);
             return -EINVAL;
         } else if (rs_is_reshaping(rs)) {
             DMERR("'rebuild' specified while raid set is being reshaped (reshape_position=%llu)",
                   (unsigned long long) mddev->reshape_position);
             return -EINVAL;
         }
     }
 
     /*
      * Now we set the Faulty bit for those devices that are
      * recorded in the superblock as failed.
      */
     sb_retrieve_failed_devices(sb, failed_devices);
     rdev_for_each(r, mddev) {
         if (test_bit(Journal, &rdev->flags) ||
             !r->sb_page)
             continue;
         sb2 = page_address(r->sb_page);
         sb2->failed_devices = 0;
         memset(sb2->extended_failed_devices, 0, sizeof(sb2->extended_failed_devices));
 
         /*
          * Check for any device re-ordering.
          */
         if (!test_bit(FirstUse, &r->flags) && (r->raid_disk >= 0)) {
             role = le32_to_cpu(sb2->array_position);
             if (role < 0)
                 continue;
 
             if (role != r->raid_disk) {
                 if (rs_is_raid10(rs) && __is_raid10_near(mddev->layout)) {
                     if (mddev->raid_disks % __raid10_near_copies(mddev->layout) ||
                         rs->raid_disks % rs->raid10_copies) {
                         rs->ti->error =
                             "Cannot change raid10 near set to odd # of devices!";
                         return -EINVAL;
                     }
 
                     sb2->array_position = cpu_to_le32(r->raid_disk);
 
                 } else if (!(rs_is_raid10(rs) && rt_is_raid0(rs->raid_type)) &&
                        !(rs_is_raid0(rs) && rt_is_raid10(rs->raid_type)) &&
                        !rt_is_raid1(rs->raid_type)) {
                     rs->ti->error = "Cannot change device positions in raid set";
                     return -EINVAL;
                 }
 
                 DMINFO("raid device #%d now at position #%d", role, r->raid_disk);
             }
 
             /*
              * Partial recovery is performed on
              * returning failed devices.
              */
             if (test_bit(role, (void *) failed_devices))
                 set_bit(Faulty, &r->flags);
         }
     }
 
     return 0;
 }
 
 static int super_validate(struct raid_set *rs, struct md_rdev *rdev)
 {
     struct mddev *mddev = &rs->md;
     struct dm_raid_superblock *sb;
 
     if (rs_is_raid0(rs) || !rdev->sb_page || rdev->raid_disk < 0)
         return 0;
 
     sb = page_address(rdev->sb_page);
 
     /*
      * If mddev->events is not set, we know we have not yet initialized
      * the array.
      */
     if (!mddev->events && super_init_validation(rs, rdev))
         return -EINVAL;
 
     if (le32_to_cpu(sb->compat_features) &&
         le32_to_cpu(sb->compat_features) != FEATURE_FLAG_SUPPORTS_V190) {
         rs->ti->error = "Unable to assemble array: Unknown flag(s) in compatible feature flags";
         return -EINVAL;
     }
 
     if (sb->incompat_features) {
         rs->ti->error = "Unable to assemble array: No incompatible feature flags supported yet";
         return -EINVAL;
     }
 
     /* Enable bitmap creation on @rs unless no metadevs or raid0 or journaled raid4/5/6 set. */
     mddev->bitmap_info.offset = (rt_is_raid0(rs->raid_type) || rs->journal_dev.dev) ? 0 : to_sector(4096);
     mddev->bitmap_info.default_offset = mddev->bitmap_info.offset;
 
     if (!test_and_clear_bit(FirstUse, &rdev->flags)) {
         /*
          * Retrieve rdev size stored in superblock to be prepared for shrink.
          * Check extended superblock members are present otherwise the size
          * will not be set!
          */
         if (le32_to_cpu(sb->compat_features) & FEATURE_FLAG_SUPPORTS_V190)
             rdev->sectors = le64_to_cpu(sb->sectors);
 
         rdev->recovery_offset = le64_to_cpu(sb->disk_recovery_offset);
         if (rdev->recovery_offset == MaxSector)
             set_bit(In_sync, &rdev->flags);
         /*
          * If no reshape in progress -> we're recovering single
          * disk(s) and have to set the device(s) to out-of-sync
          */
         else if (!rs_is_reshaping(rs))
             clear_bit(In_sync, &rdev->flags); /* Mandatory for recovery */
     }
 
     /*
      * If a device comes back, set it as not In_sync and no longer faulty.
      */
     if (test_and_clear_bit(Faulty, &rdev->flags)) {
         rdev->recovery_offset = 0;
         clear_bit(In_sync, &rdev->flags);
         rdev->saved_raid_disk = rdev->raid_disk;
     }
 
     /* Reshape support -> restore repective data offsets */
     rdev->data_offset = le64_to_cpu(sb->data_offset);
     rdev->new_data_offset = le64_to_cpu(sb->new_data_offset);
 
     return 0;
 }
 
 /*
  * Analyse superblocks and select the freshest.
  */
 static int analyse_superblocks(struct dm_target *ti, struct raid_set *rs)
 {
     int r;
     struct md_rdev *rdev, *freshest;
     struct mddev *mddev = &rs->md;
 
     freshest = NULL;
     rdev_for_each(rdev, mddev) {
         if (test_bit(Journal, &rdev->flags))
             continue;
 
         if (!rdev->meta_bdev)
             continue;
 
         /* Set superblock offset/size for metadata device. */
         rdev->sb_start = 0;
         rdev->sb_size = bdev_logical_block_size(rdev->meta_bdev);
         if (rdev->sb_size < sizeof(struct dm_raid_superblock) || rdev->sb_size > PAGE_SIZE) {
             DMERR("superblock size of a logical block is no longer valid");
             return -EINVAL;
         }
 
         /*
          * Skipping super_load due to CTR_FLAG_SYNC will cause
          * the array to undergo initialization again as
          * though it were new.  This is the intended effect
          * of the "sync" directive.
          *
          * With reshaping capability added, we must ensure that
          * that the "sync" directive is disallowed during the reshape.
          */
         if (test_bit(__CTR_FLAG_SYNC, &rs->ctr_flags))
             continue;
 
         r = super_load(rdev, freshest);
 
         switch (r) {
         case 1:
             freshest = rdev;
             break;
         case 0:
             break;
         default:
             /* This is a failure to read the superblock from the metadata device. */
             /*
              * We have to keep any raid0 data/metadata device pairs or
              * the MD raid0 personality will fail to start the array.
              */
             if (rs_is_raid0(rs))
                 continue;
 
             /*
              * We keep the dm_devs to be able to emit the device tuple
              * properly on the table line in raid_status() (rather than
              * mistakenly acting as if '- -' got passed into the constructor).
              *
              * The rdev has to stay on the same_set list to allow for
              * the attempt to restore faulty devices on second resume.
              */
             rdev->raid_disk = rdev->saved_raid_disk = -1;
             break;
         }
     }
 
     if (!freshest)
         return 0;
 
     /*
      * Validation of the freshest device provides the source of
      * validation for the remaining devices.
      */
     rs->ti->error = "Unable to assemble array: Invalid superblocks";
     if (super_validate(rs, freshest))
         return -EINVAL;
 
     if (validate_raid_redundancy(rs)) {
         rs->ti->error = "Insufficient redundancy to activate array";
         return -EINVAL;
     }
 
     rdev_for_each(rdev, mddev)
         if (!test_bit(Journal, &rdev->flags) &&
             rdev != freshest &&
             super_validate(rs, rdev))
             return -EINVAL;
     return 0;
 }
 
 /*
  * Adjust data_offset and new_data_offset on all disk members of @rs
  * for out of place reshaping if requested by contructor
  *
  * We need free space at the beginning of each raid disk for forward
  * and at the end for backward reshapes which userspace has to provide
  * via remapping/reordering of space.
  */
 static int rs_adjust_data_offsets(struct raid_set *rs)
 {
     sector_t data_offset = 0, new_data_offset = 0;
     struct md_rdev *rdev;
 
     /* Constructor did not request data offset change */
     if (!test_bit(__CTR_FLAG_DATA_OFFSET, &rs->ctr_flags)) {
         if (!rs_is_reshapable(rs))
             goto out;
 
         return 0;
     }
 
     /* HM FIXME: get In_Sync raid_dev? */
     rdev = &rs->dev[0].rdev;
 
     if (rs->delta_disks < 0) {
         /*
          * Removing disks (reshaping backwards):
          *
          * - before reshape: data is at offset 0 and free space
          *           is at end of each component LV
          *
          * - after reshape: data is at offset rs->data_offset != 0 on each component LV
          */
         data_offset = 0;
         new_data_offset = rs->data_offset;
 
     } else if (rs->delta_disks > 0) {
         /*
          * Adding disks (reshaping forwards):
          *
          * - before reshape: data is at offset rs->data_offset != 0 and
          *           free space is at begin of each component LV
          *
          * - after reshape: data is at offset 0 on each component LV
          */
         data_offset = rs->data_offset;
         new_data_offset = 0;
 
     } else {
         /*
          * User space passes in 0 for data offset after having removed reshape space
          *
          * - or - (data offset != 0)
          *
          * Changing RAID layout or chunk size -> toggle offsets
          *
          * - before reshape: data is at offset rs->data_offset 0 and
          *           free space is at end of each component LV
          *           -or-
          *                   data is at offset rs->data_offset != 0 and
          *           free space is at begin of each component LV
          *
          * - after reshape: data is at offset 0 if it was at offset != 0
          *                  or at offset != 0 if it was at offset 0
          *                  on each component LV
          *
          */
         data_offset = rs->data_offset ? rdev->data_offset : 0;
         new_data_offset = data_offset ? 0 : rs->data_offset;
         set_bit(RT_FLAG_UPDATE_SBS, &rs->runtime_flags);
     }
 
     /*
      * Make sure we got a minimum amount of free sectors per device
      */
     if (rs->data_offset &&
         bdev_nr_sectors(rdev->bdev) - rs->md.dev_sectors < MIN_FREE_RESHAPE_SPACE) {
         rs->ti->error = data_offset ? "No space for forward reshape" :
                           "No space for backward reshape";
         return -ENOSPC;
     }
 out:
     /*
      * Raise recovery_cp in case data_offset != 0 to
      * avoid false recovery positives in the constructor.
      */
     if (rs->md.recovery_cp < rs->md.dev_sectors)
         rs->md.recovery_cp += rs->dev[0].rdev.data_offset;
 
     /* Adjust data offsets on all rdevs but on any raid4/5/6 journal device */
     rdev_for_each(rdev, &rs->md) {
         if (!test_bit(Journal, &rdev->flags)) {
             rdev->data_offset = data_offset;
             rdev->new_data_offset = new_data_offset;
         }
     }
 
     return 0;
 }
 
 /* Userpace reordered disks -> adjust raid_disk indexes in @rs */
 static void __reorder_raid_disk_indexes(struct raid_set *rs)
 {
     int i = 0;
     struct md_rdev *rdev;
 
     rdev_for_each(rdev, &rs->md) {
         if (!test_bit(Journal, &rdev->flags)) {
             rdev->raid_disk = i++;
             rdev->saved_raid_disk = rdev->new_raid_disk = -1;
         }
     }
 }
 
 /*
  * Setup @rs for takeover by a different raid level
  */
 static int rs_setup_takeover(struct raid_set *rs)
 {
     struct mddev *mddev = &rs->md;
     struct md_rdev *rdev;
     unsigned int d = mddev->raid_disks = rs->raid_disks;
     sector_t new_data_offset = rs->dev[0].rdev.data_offset ? 0 : rs->data_offset;
 
     if (rt_is_raid10(rs->raid_type)) {
         if (rs_is_raid0(rs)) {
             /* Userpace reordered disks -> adjust raid_disk indexes */
             __reorder_raid_disk_indexes(rs);
 
             /* raid0 -> raid10_far layout */
             mddev->layout = raid10_format_to_md_layout(rs, ALGORITHM_RAID10_FAR,
                                    rs->raid10_copies);
         } else if (rs_is_raid1(rs))
             /* raid1 -> raid10_near layout */
             mddev->layout = raid10_format_to_md_layout(rs, ALGORITHM_RAID10_NEAR,
                                    rs->raid_disks);
         else
             return -EINVAL;
 
     }
 
     clear_bit(MD_ARRAY_FIRST_USE, &mddev->flags);
     mddev->recovery_cp = MaxSector;
 
     while (d--) {
         rdev = &rs->dev[d].rdev;
 
         if (test_bit(d, (void *) rs->rebuild_disks)) {
             clear_bit(In_sync, &rdev->flags);
             clear_bit(Faulty, &rdev->flags);
             mddev->recovery_cp = rdev->recovery_offset = 0;
             /* Bitmap has to be created when we do an "up" takeover */
             set_bit(MD_ARRAY_FIRST_USE, &mddev->flags);
         }
 
         rdev->new_data_offset = new_data_offset;
     }
 
     return 0;
 }
 
 /* Prepare @rs for reshape */
 static int rs_prepare_reshape(struct raid_set *rs)
 {
     bool reshape;
     struct mddev *mddev = &rs->md;
 
     if (rs_is_raid10(rs)) {
         if (rs->raid_disks != mddev->raid_disks &&
             __is_raid10_near(mddev->layout) &&
             rs->raid10_copies &&
             rs->raid10_copies != __raid10_near_copies(mddev->layout)) {
             /*
              * raid disk have to be multiple of data copies to allow this conversion,
              *
              * This is actually not a reshape it is a
              * rebuild of any additional mirrors per group
              */
             if (rs->raid_disks % rs->raid10_copies) {
                 rs->ti->error = "Can't reshape raid10 mirror groups";
                 return -EINVAL;
             }
 
             /* Userpace reordered disks to add/remove mirrors -> adjust raid_disk indexes */
             __reorder_raid_disk_indexes(rs);
             mddev->layout = raid10_format_to_md_layout(rs, ALGORITHM_RAID10_NEAR,
                                    rs->raid10_copies);
             mddev->new_layout = mddev->layout;
             reshape = false;
         } else
             reshape = true;
 
     } else if (rs_is_raid456(rs))
         reshape = true;
 
     else if (rs_is_raid1(rs)) {
         if (rs->delta_disks) {
             /* Process raid1 via delta_disks */
             mddev->degraded = rs->delta_disks < 0 ? -rs->delta_disks : rs->delta_disks;
             reshape = true;
         } else {
             /* Process raid1 without delta_disks */
             mddev->raid_disks = rs->raid_disks;
             reshape = false;
         }
     } else {
         rs->ti->error = "Called with bogus raid type";
         return -EINVAL;
     }
 
     if (reshape) {
         set_bit(RT_FLAG_RESHAPE_RS, &rs->runtime_flags);
         set_bit(RT_FLAG_UPDATE_SBS, &rs->runtime_flags);
     } else if (mddev->raid_disks < rs->raid_disks)
         /* Create new superblocks and bitmaps, if any new disks */
         set_bit(RT_FLAG_UPDATE_SBS, &rs->runtime_flags);
 
     return 0;
 }
 
 /* Get reshape sectors from data_offsets or raid set */
 static sector_t _get_reshape_sectors(struct raid_set *rs)
 {
     struct md_rdev *rdev;
     sector_t reshape_sectors = 0;
 
     rdev_for_each(rdev, &rs->md)
         if (!test_bit(Journal, &rdev->flags)) {
             reshape_sectors = (rdev->data_offset > rdev->new_data_offset) ?
                     rdev->data_offset - rdev->new_data_offset :
                     rdev->new_data_offset - rdev->data_offset;
             break;
         }
 
     return max(reshape_sectors, (sector_t) rs->data_offset);
 }
 
 /*
  * Reshape:
  * - change raid layout
  * - change chunk size
  * - add disks
  * - remove disks
  */
 static int rs_setup_reshape(struct raid_set *rs)
 {
     int r = 0;
     unsigned int cur_raid_devs, d;
     sector_t reshape_sectors = _get_reshape_sectors(rs);
     struct mddev *mddev = &rs->md;
     struct md_rdev *rdev;
 
     mddev->delta_disks = rs->delta_disks;
     cur_raid_devs = mddev->raid_disks;
 
     /* Ignore impossible layout change whilst adding/removing disks */
     if (mddev->delta_disks &&
         mddev->layout != mddev->new_layout) {
         DMINFO("Ignoring invalid layout change with delta_disks=%d", rs->delta_disks);
         mddev->new_layout = mddev->layout;
     }
 
     /*
      * Adjust array size:
      *
      * - in case of adding disk(s), array size has
      *   to grow after the disk adding reshape,
      *   which'll hapen in the event handler;
      *   reshape will happen forward, so space has to
      *   be available at the beginning of each disk
      *
      * - in case of removing disk(s), array size
      *   has to shrink before starting the reshape,
      *   which'll happen here;
      *   reshape will happen backward, so space has to
      *   be available at the end of each disk
      *
      * - data_offset and new_data_offset are
      *   adjusted for aforementioned out of place
      *   reshaping based on userspace passing in
      *   the "data_offset <sectors>" key/value
      *   pair via the constructor
      */
 
     /* Add disk(s) */
     if (rs->delta_disks > 0) {
         /* Prepare disks for check in raid4/5/6/10 {check|start}_reshape */
         for (d = cur_raid_devs; d < rs->raid_disks; d++) {
             rdev = &rs->dev[d].rdev;
             clear_bit(In_sync, &rdev->flags);
 
             /*
              * save_raid_disk needs to be -1, or recovery_offset will be set to 0
              * by md, which'll store that erroneously in the superblock on reshape
              */
             rdev->saved_raid_disk = -1;
             rdev->raid_disk = d;
 
             rdev->sectors = mddev->dev_sectors;
             rdev->recovery_offset = rs_is_raid1(rs) ? 0 : MaxSector;
         }
 
         mddev->reshape_backwards = 0; /* adding disk(s) -> forward reshape */
 
     /* Remove disk(s) */
     } else if (rs->delta_disks < 0) {
         r = rs_set_dev_and_array_sectors(rs, rs->ti->len, true);
         mddev->reshape_backwards = 1; /* removing disk(s) -> backward reshape */
 
     /* Change layout and/or chunk size */
     } else {
         /*
          * Reshape layout (e.g. raid5_ls -> raid5_n) and/or chunk size:
          *
          * keeping number of disks and do layout change ->
          *
          * toggle reshape_backward depending on data_offset:
          *
          * - free space upfront -> reshape forward
          *
          * - free space at the end -> reshape backward
          *
          *
          * This utilizes free reshape space avoiding the need
          * for userspace to move (parts of) LV segments in
          * case of layout/chunksize change  (for disk
          * adding/removing reshape space has to be at
          * the proper address (see above with delta_disks):
          *
          * add disk(s)   -> begin
          * remove disk(s)-> end
          */
         mddev->reshape_backwards = rs->dev[0].rdev.data_offset ? 0 : 1;
     }
 
     /*
      * Adjust device size for forward reshape
      * because md_finish_reshape() reduces it.
      */
     if (!mddev->reshape_backwards)
         rdev_for_each(rdev, &rs->md)
             if (!test_bit(Journal, &rdev->flags))
                 rdev->sectors += reshape_sectors;
 
     return r;
 }
 
 /*
  * If the md resync thread has updated superblock with max reshape position
  * at the end of a reshape but not (yet) reset the layout configuration
  * changes -> reset the latter.
  */
 static void rs_reset_inconclusive_reshape(struct raid_set *rs)
 {
     if (!rs_is_reshaping(rs) && rs_is_layout_change(rs, true)) {
         rs_set_cur(rs);
         rs->md.delta_disks = 0;
         rs->md.reshape_backwards = 0;
     }
 }
 
 /*
  * Enable/disable discard support on RAID set depending on
  * RAID level and discard properties of underlying RAID members.
  */
 static void configure_discard_support(struct raid_set *rs)
 {
     int i;
     bool raid456;
     struct dm_target *ti = rs->ti;
 
     /*
      * XXX: RAID level 4,5,6 require zeroing for safety.
      */
     raid456 = rs_is_raid456(rs);
 
     for (i = 0; i < rs->raid_disks; i++) {
         if (!rs->dev[i].rdev.bdev ||
             !bdev_max_discard_sectors(rs->dev[i].rdev.bdev))
             return;
 
         if (raid456) {
             if (!devices_handle_discard_safely) {
                 DMERR("raid456 discard support disabled due to discard_zeroes_data uncertainty.");
                 DMERR("Set dm-raid.devices_handle_discard_safely=Y to override.");
                 return;
             }
         }
     }
 
     ti->num_discard_bios = 1;
 }
 
 /*
  * Construct a RAID0/1/10/4/5/6 mapping:
  * Args:
  *  <raid_type> <#raid_params> <raid_params>{0,}    \
  *  <#raid_devs> [<meta_dev1> <dev1>]{1,}
  *
  * <raid_params> varies by <raid_type>.  See 'parse_raid_params' for
  * details on possible <raid_params>.
  *
  * Userspace is free to initialize the metadata devices, hence the superblocks to
  * enforce recreation based on the passed in table parameters.
  *
  */
 static int raid_ctr(struct dm_target *ti, unsigned int argc, char **argv)
 {
     int r;
     bool resize = false;
     struct raid_type *rt;
     unsigned int num_raid_params, num_raid_devs;
     sector_t sb_array_sectors, rdev_sectors, reshape_sectors;
     struct raid_set *rs = NULL;
     const char *arg;
     struct rs_layout rs_layout;
     struct dm_arg_set as = { argc, argv }, as_nrd;
     struct dm_arg _args[] = {
         { 0, as.argc, "Cannot understand number of raid parameters" },
         { 1, 254, "Cannot understand number of raid devices parameters" }
     };
 
     arg = dm_shift_arg(&as);
     if (!arg) {
         ti->error = "No arguments";
         return -EINVAL;
     }
 
     rt = get_raid_type(arg);
     if (!rt) {
         ti->error = "Unrecognised raid_type";
         return -EINVAL;
     }
 
     /* Must have <#raid_params> */
     if (dm_read_arg_group(_args, &as, &num_raid_params, &ti->error))
         return -EINVAL;
 
     /* number of raid device tupples <meta_dev data_dev> */
     as_nrd = as;
     dm_consume_args(&as_nrd, num_raid_params);
     _args[1].max = (as_nrd.argc - 1) / 2;
     if (dm_read_arg(_args + 1, &as_nrd, &num_raid_devs, &ti->error))
         return -EINVAL;
 
     if (!__within_range(num_raid_devs, 1, MAX_RAID_DEVICES)) {
         ti->error = "Invalid number of supplied raid devices";
         return -EINVAL;
     }
 
     rs = raid_set_alloc(ti, rt, num_raid_devs);
     if (IS_ERR(rs))
         return PTR_ERR(rs);
 
     r = parse_raid_params(rs, &as, num_raid_params);
     if (r)
         goto bad;
 
     r = parse_dev_params(rs, &as);
     if (r)
         goto bad;
 
     rs->md.sync_super = super_sync;
 
     /*
      * Calculate ctr requested array and device sizes to allow
      * for superblock analysis needing device sizes defined.
      *
      * Any existing superblock will overwrite the array and device sizes
      */
     r = rs_set_dev_and_array_sectors(rs, rs->ti->len, false);
     if (r)
         goto bad;
 
     /* Memorize just calculated, potentially larger sizes to grow the raid set in preresume */
     rs->array_sectors = rs->md.array_sectors;
     rs->dev_sectors = rs->md.dev_sectors;
 
     /*
      * Backup any new raid set level, layout, ...
      * requested to be able to compare to superblock
      * members for conversion decisions.
      */
     rs_config_backup(rs, &rs_layout);
 
     r = analyse_superblocks(ti, rs);
     if (r)
         goto bad;
 
     /* All in-core metadata now as of current superblocks after calling analyse_superblocks() */
     sb_array_sectors = rs->md.array_sectors;
     rdev_sectors = __rdev_sectors(rs);
     if (!rdev_sectors) {
         ti->error = "Invalid rdev size";
         r = -EINVAL;
         goto bad;
     }
 
 
     reshape_sectors = _get_reshape_sectors(rs);
     if (rs->dev_sectors != rdev_sectors) {
         resize = (rs->dev_sectors != rdev_sectors - reshape_sectors);
         if (rs->dev_sectors > rdev_sectors - reshape_sectors)
             set_bit(RT_FLAG_RS_GROW, &rs->runtime_flags);
     }
 
     INIT_WORK(&rs->md.event_work, do_table_event);
     ti->private = rs;
     ti->num_flush_bios = 1;
     ti->needs_bio_set_dev = true;
 
     /* Restore any requested new layout for conversion decision */
     rs_config_restore(rs, &rs_layout);
 
     /*
      * Now that we have any superblock metadata available,
      * check for new, recovering, reshaping, to be taken over,
      * to be reshaped or an existing, unchanged raid set to
      * run in sequence.
      */
     if (test_bit(MD_ARRAY_FIRST_USE, &rs->md.flags)) {
         /* A new raid6 set has to be recovered to ensure proper parity and Q-Syndrome */
         if (rs_is_raid6(rs) &&
             test_bit(__CTR_FLAG_NOSYNC, &rs->ctr_flags)) {
             ti->error = "'nosync' not allowed for new raid6 set";
             r = -EINVAL;
             goto bad;
         }
         rs_setup_recovery(rs, 0);
         set_bit(RT_FLAG_UPDATE_SBS, &rs->runtime_flags);
         rs_set_new(rs);
     } else if (rs_is_recovering(rs)) {
         /* A recovering raid set may be resized */
         goto size_check;
     } else if (rs_is_reshaping(rs)) {
         /* Have to reject size change request during reshape */
         if (resize) {
             ti->error = "Can't resize a reshaping raid set";
             r = -EPERM;
             goto bad;
         }
         /* skip setup rs */
     } else if (rs_takeover_requested(rs)) {
         if (rs_is_reshaping(rs)) {
             ti->error = "Can't takeover a reshaping raid set";
             r = -EPERM;
             goto bad;
         }
 
         /* We can't takeover a journaled raid4/5/6 */
         if (test_bit(__CTR_FLAG_JOURNAL_DEV, &rs->ctr_flags)) {
             ti->error = "Can't takeover a journaled raid4/5/6 set";
             r = -EPERM;
             goto bad;
         }
 
         /*
          * If a takeover is needed, userspace sets any additional
          * devices to rebuild and we can check for a valid request here.
          *
          * If acceptible, set the level to the new requested
          * one, prohibit requesting recovery, allow the raid
          * set to run and store superblocks during resume.
          */
         r = rs_check_takeover(rs);
         if (r)
             goto bad;
 
         r = rs_setup_takeover(rs);
         if (r)
             goto bad;
 
         set_bit(RT_FLAG_UPDATE_SBS, &rs->runtime_flags);
         /* Takeover ain't recovery, so disable recovery */
         rs_setup_recovery(rs, MaxSector);
         rs_set_new(rs);
     } else if (rs_reshape_requested(rs)) {
         /* Only request grow on raid set size extensions, not on reshapes. */
         clear_bit(RT_FLAG_RS_GROW, &rs->runtime_flags);
 
         /*
          * No need to check for 'ongoing' takeover here, because takeover
          * is an instant operation as oposed to an ongoing reshape.
          */
 
         /* We can't reshape a journaled raid4/5/6 */
         if (test_bit(__CTR_FLAG_JOURNAL_DEV, &rs->ctr_flags)) {
             ti->error = "Can't reshape a journaled raid4/5/6 set";
             r = -EPERM;
             goto bad;
         }
 
         /* Out-of-place space has to be available to allow for a reshape unless raid1! */
         if (reshape_sectors || rs_is_raid1(rs)) {
             /*
               * We can only prepare for a reshape here, because the
               * raid set needs to run to provide the repective reshape
               * check functions via its MD personality instance.
               *
               * So do the reshape check after md_run() succeeded.
               */
             r = rs_prepare_reshape(rs);
             if (r)
                 goto bad;
 
             /* Reshaping ain't recovery, so disable recovery */
             rs_setup_recovery(rs, MaxSector);
         }
         rs_set_cur(rs);
     } else {
 size_check:
         /* May not set recovery when a device rebuild is requested */
         if (test_bit(__CTR_FLAG_REBUILD, &rs->ctr_flags)) {
             clear_bit(RT_FLAG_RS_GROW, &rs->runtime_flags);
             set_bit(RT_FLAG_UPDATE_SBS, &rs->runtime_flags);
             rs_setup_recovery(rs, MaxSector);
         } else if (test_bit(RT_FLAG_RS_GROW, &rs->runtime_flags)) {
             /*
              * Set raid set to current size, i.e. size as of
              * superblocks to grow to larger size in preresume.
              */
             r = rs_set_dev_and_array_sectors(rs, sb_array_sectors, false);
             if (r)
                 goto bad;
 
             rs_setup_recovery(rs, rs->md.recovery_cp < rs->md.dev_sectors ? rs->md.recovery_cp : rs->md.dev_sectors);
         } else {
             /* This is no size change or it is shrinking, update size and record in superblocks */
             r = rs_set_dev_and_array_sectors(rs, rs->ti->len, false);
             if (r)
                 goto bad;
 
             if (sb_array_sectors > rs->array_sectors)
                 set_bit(RT_FLAG_UPDATE_SBS, &rs->runtime_flags);
         }
         rs_set_cur(rs);
     }
 
     /* If constructor requested it, change data and new_data offsets */
     r = rs_adjust_data_offsets(rs);
     if (r)
         goto bad;
 
     /* Catch any inconclusive reshape superblock content. */
     rs_reset_inconclusive_reshape(rs);
 
     /* Start raid set read-only and assumed clean to change in raid_resume() */
     rs->md.ro = 1;
     rs->md.in_sync = 1;
 
     /* Keep array frozen until resume. */
     set_bit(MD_RECOVERY_FROZEN, &rs->md.recovery);
 
     /* Has to be held on running the array */
     mddev_lock_nointr(&rs->md);
     r = md_run(&rs->md);
     rs->md.in_sync = 0; /* Assume already marked dirty */
     if (r) {
         ti->error = "Failed to run raid array";
         mddev_unlock(&rs->md);
         goto bad;
     }
 
     r = md_start(&rs->md);
     if (r) {
         ti->error = "Failed to start raid array";
         mddev_unlock(&rs->md);
         goto bad_md_start;
     }
 
     /* If raid4/5/6 journal mode explicitly requested (only possible with journal dev) -> set it */
     if (test_bit(__CTR_FLAG_JOURNAL_MODE, &rs->ctr_flags)) {
         r = r5c_journal_mode_set(&rs->md, rs->journal_dev.mode);
         if (r) {
             ti->error = "Failed to set raid4/5/6 journal mode";
             mddev_unlock(&rs->md);
             goto bad_journal_mode_set;
         }
     }
 
     mddev_suspend(&rs->md);
     set_bit(RT_FLAG_RS_SUSPENDED, &rs->runtime_flags);
 
     /* Try to adjust the raid4/5/6 stripe cache size to the stripe size */
     if (rs_is_raid456(rs)) {
         r = rs_set_raid456_stripe_cache(rs);
         if (r)
             goto bad_stripe_cache;
     }
 
     /* Now do an early reshape check */
     if (test_bit(RT_FLAG_RESHAPE_RS, &rs->runtime_flags)) {
         r = rs_check_reshape(rs);
         if (r)
             goto bad_check_reshape;
 
         /* Restore new, ctr requested layout to perform check */
         rs_config_restore(rs, &rs_layout);
 
         if (rs->md.pers->start_reshape) {
             r = rs->md.pers->check_reshape(&rs->md);
             if (r) {
                 ti->error = "Reshape check failed";
                 goto bad_check_reshape;
             }
         }
     }
 
     /* Disable/enable discard support on raid set. */
     configure_discard_support(rs);
 
     mddev_unlock(&rs->md);
     return 0;
 
 bad_md_start:
 bad_journal_mode_set:
 bad_stripe_cache:
 bad_check_reshape:
     md_stop(&rs->md);
 bad:
     raid_set_free(rs);
 
     return r;
 }
 
 static void raid_dtr(struct dm_target *ti)
 {
     struct raid_set *rs = ti->private;
 
     md_stop(&rs->md);
     raid_set_free(rs);
 }
 
 static int raid_map(struct dm_target *ti, struct bio *bio)
 {
     struct raid_set *rs = ti->private;
     struct mddev *mddev = &rs->md;
 
     /*
      * If we're reshaping to add disk(s)), ti->len and
      * mddev->array_sectors will differ during the process
      * (ti->len > mddev->array_sectors), so we have to requeue
      * bios with addresses > mddev->array_sectors here or
      * there will occur accesses past EOD of the component
      * data images thus erroring the raid set.
      */
     if (unlikely(bio_end_sector(bio) > mddev->array_sectors))
         return DM_MAPIO_REQUEUE;
 
     md_handle_request(mddev, bio);
 
     return DM_MAPIO_SUBMITTED;
 }
 
 /* Return sync state string for @state */
 enum sync_state { st_frozen, st_reshape, st_resync, st_check, st_repair, st_recover, st_idle };
 static const char *sync_str(enum sync_state state)
 {
     /* Has to be in above sync_state order! */
     static const char *sync_strs[] = {
         "frozen",
         "reshape",
         "resync",
         "check",
         "repair",
         "recover",
         "idle"
     };
 
     return __within_range(state, 0, ARRAY_SIZE(sync_strs) - 1) ? sync_strs[state] : "undef";
 };
 
 /* Return enum sync_state for @mddev derived from @recovery flags */
 static enum sync_state decipher_sync_action(struct mddev *mddev, unsigned long recovery)
 {
     if (test_bit(MD_RECOVERY_FROZEN, &recovery))
         return st_frozen;
 
     /* The MD sync thread can be done with io or be interrupted but still be running */
     if (!test_bit(MD_RECOVERY_DONE, &recovery) &&
         (test_bit(MD_RECOVERY_RUNNING, &recovery) ||
          (!mddev->ro && test_bit(MD_RECOVERY_NEEDED, &recovery)))) {
         if (test_bit(MD_RECOVERY_RESHAPE, &recovery))
             return st_reshape;
 
         if (test_bit(MD_RECOVERY_SYNC, &recovery)) {
             if (!test_bit(MD_RECOVERY_REQUESTED, &recovery))
                 return st_resync;
             if (test_bit(MD_RECOVERY_CHECK, &recovery))
                 return st_check;
             return st_repair;
         }
 
         if (test_bit(MD_RECOVERY_RECOVER, &recovery))
             return st_recover;
 
         if (mddev->reshape_position != MaxSector)
             return st_reshape;
     }
 
     return st_idle;
 }
 
 /*
  * Return status string for @rdev
  *
  * Status characters:
  *
  *  'D' = Dead/Failed raid set component or raid4/5/6 journal device
  *  'a' = Alive but not in-sync raid set component _or_ alive raid4/5/6 'write_back' journal device
  *  'A' = Alive and in-sync raid set component _or_ alive raid4/5/6 'write_through' journal device
  *  '-' = Non-existing device (i.e. uspace passed '- -' into the ctr)
  */
 static const char *__raid_dev_status(struct raid_set *rs, struct md_rdev *rdev)
 {
     if (!rdev->bdev)
         return "-";
     else if (test_bit(Faulty, &rdev->flags))
         return "D";
     else if (test_bit(Journal, &rdev->flags))
         return (rs->journal_dev.mode == R5C_JOURNAL_MODE_WRITE_THROUGH) ? "A" : "a";
     else if (test_bit(RT_FLAG_RS_RESYNCING, &rs->runtime_flags) ||
          (!test_bit(RT_FLAG_RS_IN_SYNC, &rs->runtime_flags) &&
           !test_bit(In_sync, &rdev->flags)))
         return "a";
     else
         return "A";
 }
 
 /* Helper to return resync/reshape progress for @rs and runtime flags for raid set in sync / resynching */
 static sector_t rs_get_progress(struct raid_set *rs, unsigned long recovery,
                 enum sync_state state, sector_t resync_max_sectors)
 {
     sector_t r;
     struct mddev *mddev = &rs->md;
 
     clear_bit(RT_FLAG_RS_IN_SYNC, &rs->runtime_flags);
     clear_bit(RT_FLAG_RS_RESYNCING, &rs->runtime_flags);
 
     if (rs_is_raid0(rs)) {
         r = resync_max_sectors;
         set_bit(RT_FLAG_RS_IN_SYNC, &rs->runtime_flags);
 
     } else {
         if (state == st_idle && !test_bit(MD_RECOVERY_INTR, &recovery))
             r = mddev->recovery_cp;
         else
             r = mddev->curr_resync_completed;
 
         if (state == st_idle && r >= resync_max_sectors) {
             /*
              * Sync complete.
              */
             /* In case we have finished recovering, the array is in sync. */
             if (test_bit(MD_RECOVERY_RECOVER, &recovery))
                 set_bit(RT_FLAG_RS_IN_SYNC, &rs->runtime_flags);
 
         } else if (state == st_recover)
             /*
              * In case we are recovering, the array is not in sync
              * and health chars should show the recovering legs.
              *
              * Already retrieved recovery offset from curr_resync_completed above.
              */
             ;
 
         else if (state == st_resync || state == st_reshape)
             /*
              * If "resync/reshape" is occurring, the raid set
              * is or may be out of sync hence the health
              * characters shall be 'a'.
              */
             set_bit(RT_FLAG_RS_RESYNCING, &rs->runtime_flags);
 
         else if (state == st_check || state == st_repair)
             /*
              * If "check" or "repair" is occurring, the raid set has
              * undergone an initial sync and the health characters
              * should not be 'a' anymore.
              */
             set_bit(RT_FLAG_RS_IN_SYNC, &rs->runtime_flags);
 
         else if (test_bit(MD_RECOVERY_NEEDED, &recovery))
             /*
              * We are idle and recovery is needed, prevent 'A' chars race
              * caused by components still set to in-sync by constructor.
              */
             set_bit(RT_FLAG_RS_RESYNCING, &rs->runtime_flags);
 
         else {
             /*
              * We are idle and the raid set may be doing an initial
              * sync, or it may be rebuilding individual components.
              * If all the devices are In_sync, then it is the raid set
              * that is being initialized.
              */
             struct md_rdev *rdev;
 
             set_bit(RT_FLAG_RS_IN_SYNC, &rs->runtime_flags);
             rdev_for_each(rdev, mddev)
                 if (!test_bit(Journal, &rdev->flags) &&
                     !test_bit(In_sync, &rdev->flags)) {
                     clear_bit(RT_FLAG_RS_IN_SYNC, &rs->runtime_flags);
                     break;
                 }
         }
     }
 
     return min(r, resync_max_sectors);
 }
 
 /* Helper to return @dev name or "-" if !@dev */
 static const char *__get_dev_name(struct dm_dev *dev)
 {
     return dev ? dev->name : "-";
 }
 
 static void raid_status(struct dm_target *ti, status_type_t type,
             unsigned int status_flags, char *result, unsigned int maxlen)
 {
     struct raid_set *rs = ti->private;
     struct mddev *mddev = &rs->md;
     struct r5conf *conf = rs_is_raid456(rs) ? mddev->private : NULL;
     int i, max_nr_stripes = conf ? conf->max_nr_stripes : 0;
     unsigned long recovery;
     unsigned int raid_param_cnt = 1; /* at least 1 for chunksize */
     unsigned int sz = 0;
     unsigned int rebuild_writemostly_count = 0;
     sector_t progress, resync_max_sectors, resync_mismatches;
     enum sync_state state;
     struct raid_type *rt;
 
     switch (type) {
     case STATUSTYPE_INFO:
         /* *Should* always succeed */
         rt = get_raid_type_by_ll(mddev->new_level, mddev->new_layout);
         if (!rt)
             return;
 
         DMEMIT("%s %d ", rt->name, mddev->raid_disks);
 
         /* Access most recent mddev properties for status output */
         smp_rmb();
         /* Get sensible max sectors even if raid set not yet started */
         resync_max_sectors = test_bit(RT_FLAG_RS_PRERESUMED, &rs->runtime_flags) ?
                       mddev->resync_max_sectors : mddev->dev_sectors;
         recovery = rs->md.recovery;
         state = decipher_sync_action(mddev, recovery);
         progress = rs_get_progress(rs, recovery, state, resync_max_sectors);
         resync_mismatches = (mddev->last_sync_action && !strcasecmp(mddev->last_sync_action, "check")) ?
                     atomic64_read(&mddev->resync_mismatches) : 0;
 
         /* HM FIXME: do we want another state char for raid0? It shows 'D'/'A'/'-' now */
         for (i = 0; i < rs->raid_disks; i++)
             DMEMIT(__raid_dev_status(rs, &rs->dev[i].rdev));
 
         /*
          * In-sync/Reshape ratio:
          *  The in-sync ratio shows the progress of:
          *   - Initializing the raid set
          *   - Rebuilding a subset of devices of the raid set
          *  The user can distinguish between the two by referring
          *  to the status characters.
          *
          *  The reshape ratio shows the progress of
          *  changing the raid layout or the number of
          *  disks of a raid set
          */
         DMEMIT(" %llu/%llu", (unsigned long long) progress,
                      (unsigned long long) resync_max_sectors);
 
         /*
          * v1.5.0+:
          *
          * Sync action:
          *   See Documentation/admin-guide/device-mapper/dm-raid.rst for
          *   information on each of these states.
          */
         DMEMIT(" %s", sync_str(state));
 
         /*
          * v1.5.0+:
          *
          * resync_mismatches/mismatch_cnt
          *   This field shows the number of discrepancies found when
          *   performing a "check" of the raid set.
          */
         DMEMIT(" %llu", (unsigned long long) resync_mismatches);
 
         /*
          * v1.9.0+:
          *
          * data_offset (needed for out of space reshaping)
          *   This field shows the data offset into the data
          *   image LV where the first stripes data starts.
          *
          * We keep data_offset equal on all raid disks of the set,
          * so retrieving it from the first raid disk is sufficient.
          */
         DMEMIT(" %llu", (unsigned long long) rs->dev[0].rdev.data_offset);
 
         /*
          * v1.10.0+:
          */
         DMEMIT(" %s", test_bit(__CTR_FLAG_JOURNAL_DEV, &rs->ctr_flags) ?
                   __raid_dev_status(rs, &rs->journal_dev.rdev) : "-");
         break;
 
     case STATUSTYPE_TABLE:
         /* Report the table line string you would use to construct this raid set */
 
         /*
          * Count any rebuild or writemostly argument pairs and subtract the
          * hweight count being added below of any rebuild and writemostly ctr flags.
          */
         for (i = 0; i < rs->raid_disks; i++) {
             rebuild_writemostly_count += (test_bit(i, (void *) rs->rebuild_disks) ? 2 : 0) +
                              (test_bit(WriteMostly, &rs->dev[i].rdev.flags) ? 2 : 0);
         }
         rebuild_writemostly_count -= (test_bit(__CTR_FLAG_REBUILD, &rs->ctr_flags) ? 2 : 0) +
                          (test_bit(__CTR_FLAG_WRITE_MOSTLY, &rs->ctr_flags) ? 2 : 0);
         /* Calculate raid parameter count based on ^ rebuild/writemostly argument counts and ctr flags set. */
         raid_param_cnt += rebuild_writemostly_count +
                   hweight32(rs->ctr_flags & CTR_FLAG_OPTIONS_NO_ARGS) +
                   hweight32(rs->ctr_flags & CTR_FLAG_OPTIONS_ONE_ARG) * 2;
         /* Emit table line */
         /* This has to be in the documented order for userspace! */
         DMEMIT("%s %u %u", rs->raid_type->name, raid_param_cnt, mddev->new_chunk_sectors);
         if (test_bit(__CTR_FLAG_SYNC, &rs->ctr_flags))
             DMEMIT(" %s", dm_raid_arg_name_by_flag(CTR_FLAG_SYNC));
         if (test_bit(__CTR_FLAG_NOSYNC, &rs->ctr_flags))
             DMEMIT(" %s", dm_raid_arg_name_by_flag(CTR_FLAG_NOSYNC));
         if (test_bit(__CTR_FLAG_REBUILD, &rs->ctr_flags))
             for (i = 0; i < rs->raid_disks; i++)
                 if (test_bit(i, (void *) rs->rebuild_disks))
                     DMEMIT(" %s %u", dm_raid_arg_name_by_flag(CTR_FLAG_REBUILD), i);
         if (test_bit(__CTR_FLAG_DAEMON_SLEEP, &rs->ctr_flags))
             DMEMIT(" %s %lu", dm_raid_arg_name_by_flag(CTR_FLAG_DAEMON_SLEEP),
                       mddev->bitmap_info.daemon_sleep);
         if (test_bit(__CTR_FLAG_MIN_RECOVERY_RATE, &rs->ctr_flags))
             DMEMIT(" %s %d", dm_raid_arg_name_by_flag(CTR_FLAG_MIN_RECOVERY_RATE),
                      mddev->sync_speed_min);
         if (test_bit(__CTR_FLAG_MAX_RECOVERY_RATE, &rs->ctr_flags))
             DMEMIT(" %s %d", dm_raid_arg_name_by_flag(CTR_FLAG_MAX_RECOVERY_RATE),
                      mddev->sync_speed_max);
         if (test_bit(__CTR_FLAG_WRITE_MOSTLY, &rs->ctr_flags))
             for (i = 0; i < rs->raid_disks; i++)
                 if (test_bit(WriteMostly, &rs->dev[i].rdev.flags))
                     DMEMIT(" %s %d", dm_raid_arg_name_by_flag(CTR_FLAG_WRITE_MOSTLY),
                            rs->dev[i].rdev.raid_disk);
         if (test_bit(__CTR_FLAG_MAX_WRITE_BEHIND, &rs->ctr_flags))
             DMEMIT(" %s %lu", dm_raid_arg_name_by_flag(CTR_FLAG_MAX_WRITE_BEHIND),
                       mddev->bitmap_info.max_write_behind);
         if (test_bit(__CTR_FLAG_STRIPE_CACHE, &rs->ctr_flags))
             DMEMIT(" %s %d", dm_raid_arg_name_by_flag(CTR_FLAG_STRIPE_CACHE),
                      max_nr_stripes);
         if (test_bit(__CTR_FLAG_REGION_SIZE, &rs->ctr_flags))
             DMEMIT(" %s %llu", dm_raid_arg_name_by_flag(CTR_FLAG_REGION_SIZE),
                        (unsigned long long) to_sector(mddev->bitmap_info.chunksize));
         if (test_bit(__CTR_FLAG_RAID10_COPIES, &rs->ctr_flags))
             DMEMIT(" %s %d", dm_raid_arg_name_by_flag(CTR_FLAG_RAID10_COPIES),
                      raid10_md_layout_to_copies(mddev->layout));
         if (test_bit(__CTR_FLAG_RAID10_FORMAT, &rs->ctr_flags))
             DMEMIT(" %s %s", dm_raid_arg_name_by_flag(CTR_FLAG_RAID10_FORMAT),
                      raid10_md_layout_to_format(mddev->layout));
         if (test_bit(__CTR_FLAG_DELTA_DISKS, &rs->ctr_flags))
             DMEMIT(" %s %d", dm_raid_arg_name_by_flag(CTR_FLAG_DELTA_DISKS),
                      max(rs->delta_disks, mddev->delta_disks));
         if (test_bit(__CTR_FLAG_DATA_OFFSET, &rs->ctr_flags))
             DMEMIT(" %s %llu", dm_raid_arg_name_by_flag(CTR_FLAG_DATA_OFFSET),
                        (unsigned long long) rs->data_offset);
         if (test_bit(__CTR_FLAG_JOURNAL_DEV, &rs->ctr_flags))
             DMEMIT(" %s %s", dm_raid_arg_name_by_flag(CTR_FLAG_JOURNAL_DEV),
                     __get_dev_name(rs->journal_dev.dev));
         if (test_bit(__CTR_FLAG_JOURNAL_MODE, &rs->ctr_flags))
             DMEMIT(" %s %s", dm_raid_arg_name_by_flag(CTR_FLAG_JOURNAL_MODE),
                      md_journal_mode_to_dm_raid(rs->journal_dev.mode));
         DMEMIT(" %d", rs->raid_disks);
         for (i = 0; i < rs->raid_disks; i++)
             DMEMIT(" %s %s", __get_dev_name(rs->dev[i].meta_dev),
                      __get_dev_name(rs->dev[i].data_dev));
         break;
 
     case STATUSTYPE_IMA:
         rt = get_raid_type_by_ll(mddev->new_level, mddev->new_layout);
         if (!rt)
             return;
 
         DMEMIT_TARGET_NAME_VERSION(ti->type);
         DMEMIT(",raid_type=%s,raid_disks=%d", rt->name, mddev->raid_disks);
 
         /* Access most recent mddev properties for status output */
         smp_rmb();
         recovery = rs->md.recovery;
         state = decipher_sync_action(mddev, recovery);
         DMEMIT(",raid_state=%s", sync_str(state));
 
         for (i = 0; i < rs->raid_disks; i++) {
             DMEMIT(",raid_device_%d_status=", i);
             DMEMIT(__raid_dev_status(rs, &rs->dev[i].rdev));
         }
 
         if (rt_is_raid456(rt)) {
             DMEMIT(",journal_dev_mode=");
             switch (rs->journal_dev.mode) {
             case R5C_JOURNAL_MODE_WRITE_THROUGH:
                 DMEMIT("%s",
                        _raid456_journal_mode[R5C_JOURNAL_MODE_WRITE_THROUGH].param);
                 break;
             case R5C_JOURNAL_MODE_WRITE_BACK:
                 DMEMIT("%s",
                        _raid456_journal_mode[R5C_JOURNAL_MODE_WRITE_BACK].param);
                 break;
             default:
                 DMEMIT("invalid");
                 break;
             }
         }
         DMEMIT(";");
         break;
     }
 }
 
 static int raid_message(struct dm_target *ti, unsigned int argc, char **argv,
             char *result, unsigned maxlen)
 {
     struct raid_set *rs = ti->private;
     struct mddev *mddev = &rs->md;
 
     if (!mddev->pers || !mddev->pers->sync_request)
         return -EINVAL;
 
     if (!strcasecmp(argv[0], "frozen"))
         set_bit(MD_RECOVERY_FROZEN, &mddev->recovery);
     else
         clear_bit(MD_RECOVERY_FROZEN, &mddev->recovery);
 
     if (!strcasecmp(argv[0], "idle") || !strcasecmp(argv[0], "frozen")) {
         if (mddev->sync_thread) {
             set_bit(MD_RECOVERY_INTR, &mddev->recovery);
             md_unregister_thread(&mddev->sync_thread);
             md_reap_sync_thread(mddev);
         }
     } else if (decipher_sync_action(mddev, mddev->recovery) != st_idle)
         return -EBUSY;
     else if (!strcasecmp(argv[0], "resync"))
         ; /* MD_RECOVERY_NEEDED set below */
     else if (!strcasecmp(argv[0], "recover"))
         set_bit(MD_RECOVERY_RECOVER, &mddev->recovery);
     else {
         if (!strcasecmp(argv[0], "check")) {
             set_bit(MD_RECOVERY_CHECK, &mddev->recovery);
             set_bit(MD_RECOVERY_REQUESTED, &mddev->recovery);
             set_bit(MD_RECOVERY_SYNC, &mddev->recovery);
         } else if (!strcasecmp(argv[0], "repair")) {
             set_bit(MD_RECOVERY_REQUESTED, &mddev->recovery);
             set_bit(MD_RECOVERY_SYNC, &mddev->recovery);
         } else
             return -EINVAL;
     }
     if (mddev->ro == 2) {
         /* A write to sync_action is enough to justify
          * canceling read-auto mode
          */
         mddev->ro = 0;
         if (!mddev->suspended && mddev->sync_thread)
             md_wakeup_thread(mddev->sync_thread);
     }
     set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
     if (!mddev->suspended && mddev->thread)
         md_wakeup_thread(mddev->thread);
 
     return 0;
 }
 
 static int raid_iterate_devices(struct dm_target *ti,
                 iterate_devices_callout_fn fn, void *data)
 {
     struct raid_set *rs = ti->private;
     unsigned int i;
     int r = 0;
 
     for (i = 0; !r && i < rs->raid_disks; i++) {
         if (rs->dev[i].data_dev) {
             r = fn(ti, rs->dev[i].data_dev,
                    0, /* No offset on data devs */
                    rs->md.dev_sectors, data);
         }
     }
 
     return r;
 }
 
 static void raid_io_hints(struct dm_target *ti, struct queue_limits *limits)
 {
     struct raid_set *rs = ti->private;
     unsigned int chunk_size_bytes = to_bytes(rs->md.chunk_sectors);
 
     blk_limits_io_min(limits, chunk_size_bytes);
     blk_limits_io_opt(limits, chunk_size_bytes * mddev_data_stripes(rs));
 }
 
 static void raid_postsuspend(struct dm_target *ti)
 {
     struct raid_set *rs = ti->private;
 
     if (!test_and_set_bit(RT_FLAG_RS_SUSPENDED, &rs->runtime_flags)) {
         /* Writes have to be stopped before suspending to avoid deadlocks. */
         if (!test_bit(MD_RECOVERY_FROZEN, &rs->md.recovery))
             md_stop_writes(&rs->md);
 
         mddev_lock_nointr(&rs->md);
         mddev_suspend(&rs->md);
         mddev_unlock(&rs->md);
     }
 }
 
 static void attempt_restore_of_faulty_devices(struct raid_set *rs)
 {
     int i;
     uint64_t cleared_failed_devices[DISKS_ARRAY_ELEMS];
     unsigned long flags;
     bool cleared = false;
     struct dm_raid_superblock *sb;
     struct mddev *mddev = &rs->md;
     struct md_rdev *r;
 
     /* RAID personalities have to provide hot add/remove methods or we need to bail out. */
     if (!mddev->pers || !mddev->pers->hot_add_disk || !mddev->pers->hot_remove_disk)
         return;
 
     memset(cleared_failed_devices, 0, sizeof(cleared_failed_devices));
 
     for (i = 0; i < rs->raid_disks; i++) {
         r = &rs->dev[i].rdev;
         /* HM FIXME: enhance journal device recovery processing */
         if (test_bit(Journal, &r->flags))
             continue;
 
         if (test_bit(Faulty, &r->flags) &&
             r->meta_bdev && !read_disk_sb(r, r->sb_size, true)) {
             DMINFO("Faulty %s device #%d has readable super block."
                    "  Attempting to revive it.",
                    rs->raid_type->name, i);
 
             /*
              * Faulty bit may be set, but sometimes the array can
              * be suspended before the personalities can respond
              * by removing the device from the array (i.e. calling
              * 'hot_remove_disk').  If they haven't yet removed
              * the failed device, its 'raid_disk' number will be
              * '>= 0' - meaning we must call this function
              * ourselves.
              */
             flags = r->flags;
             clear_bit(In_sync, &r->flags); /* Mandatory for hot remove. */
             if (r->raid_disk >= 0) {
                 if (mddev->pers->hot_remove_disk(mddev, r)) {
                     /* Failed to revive this device, try next */
                     r->flags = flags;
                     continue;
                 }
             } else
                 r->raid_disk = r->saved_raid_disk = i;
 
             clear_bit(Faulty, &r->flags);
             clear_bit(WriteErrorSeen, &r->flags);
 
             if (mddev->pers->hot_add_disk(mddev, r)) {
                 /* Failed to revive this device, try next */
                 r->raid_disk = r->saved_raid_disk = -1;
                 r->flags = flags;
             } else {
                 clear_bit(In_sync, &r->flags);
                 r->recovery_offset = 0;
                 set_bit(i, (void *) cleared_failed_devices);
                 cleared = true;
             }
         }
     }
 
     /* If any failed devices could be cleared, update all sbs failed_devices bits */
     if (cleared) {
         uint64_t failed_devices[DISKS_ARRAY_ELEMS];
 
         rdev_for_each(r, &rs->md) {
             if (test_bit(Journal, &r->flags))
                 continue;
 
             sb = page_address(r->sb_page);
             sb_retrieve_failed_devices(sb, failed_devices);
 
             for (i = 0; i < DISKS_ARRAY_ELEMS; i++)
                 failed_devices[i] &= ~cleared_failed_devices[i];
 
             sb_update_failed_devices(sb, failed_devices);
         }
     }
 }
 
 static int __load_dirty_region_bitmap(struct raid_set *rs)
 {
     int r = 0;
 
     /* Try loading the bitmap unless "raid0", which does not have one */
     if (!rs_is_raid0(rs) &&
         !test_and_set_bit(RT_FLAG_RS_BITMAP_LOADED, &rs->runtime_flags)) {
         r = md_bitmap_load(&rs->md);
         if (r)
             DMERR("Failed to load bitmap");
     }
 
     return r;
 }
 
 /* Enforce updating all superblocks */
 static void rs_update_sbs(struct raid_set *rs)
 {
     struct mddev *mddev = &rs->md;
     int ro = mddev->ro;
 
     set_bit(MD_SB_CHANGE_DEVS, &mddev->sb_flags);
     mddev->ro = 0;
     md_update_sb(mddev, 1);
     mddev->ro = ro;
 }
 
 /*
  * Reshape changes raid algorithm of @rs to new one within personality
  * (e.g. raid6_zr -> raid6_nc), changes stripe size, adds/removes
  * disks from a raid set thus growing/shrinking it or resizes the set
  *
  * Call mddev_lock_nointr() before!
  */
 static int rs_start_reshape(struct raid_set *rs)
 {
     int r;
     struct mddev *mddev = &rs->md;
     struct md_personality *pers = mddev->pers;
 
     /* Don't allow the sync thread to work until the table gets reloaded. */
     set_bit(MD_RECOVERY_WAIT, &mddev->recovery);
 
     r = rs_setup_reshape(rs);
     if (r)
         return r;
 
     /*
      * Check any reshape constraints enforced by the personalility
      *
      * May as well already kick the reshape off so that * pers->start_reshape() becomes optional.
      */
     r = pers->check_reshape(mddev);
     if (r) {
         rs->ti->error = "pers->check_reshape() failed";
         return r;
     }
 
     /*
      * Personality may not provide start reshape method in which
      * case check_reshape above has already covered everything
      */
     if (pers->start_reshape) {
         r = pers->start_reshape(mddev);
         if (r) {
             rs->ti->error = "pers->start_reshape() failed";
             return r;
         }
     }
 
     /*
      * Now reshape got set up, update superblocks to
      * reflect the fact so that a table reload will
      * access proper superblock content in the ctr.
      */
     rs_update_sbs(rs);
 
     return 0;
 }
 
 static int raid_preresume(struct dm_target *ti)
 {
     int r;
     struct raid_set *rs = ti->private;
     struct mddev *mddev = &rs->md;
 
     /* This is a resume after a suspend of the set -> it's already started. */
     if (test_and_set_bit(RT_FLAG_RS_PRERESUMED, &rs->runtime_flags))
         return 0;
 
     /*
      * The superblocks need to be updated on disk if the
      * array is new or new devices got added (thus zeroed
      * out by userspace) or __load_dirty_region_bitmap
      * will overwrite them in core with old data or fail.
      */
     if (test_bit(RT_FLAG_UPDATE_SBS, &rs->runtime_flags))
         rs_update_sbs(rs);
 
     /* Load the bitmap from disk unless raid0 */
     r = __load_dirty_region_bitmap(rs);
     if (r)
         return r;
 
     /* We are extending the raid set size, adjust mddev/md_rdev sizes and set capacity. */
     if (test_bit(RT_FLAG_RS_GROW, &rs->runtime_flags)) {
         mddev->array_sectors = rs->array_sectors;
         mddev->dev_sectors = rs->dev_sectors;
         rs_set_rdev_sectors(rs);
         rs_set_capacity(rs);
     }
 
     /* Resize bitmap to adjust to changed region size (aka MD bitmap chunksize) or grown device size */
         if (test_bit(RT_FLAG_RS_BITMAP_LOADED, &rs->runtime_flags) && mddev->bitmap &&
         (test_bit(RT_FLAG_RS_GROW, &rs->runtime_flags) ||
          (rs->requested_bitmap_chunk_sectors &&
            mddev->bitmap_info.chunksize != to_bytes(rs->requested_bitmap_chunk_sectors)))) {
         int chunksize = to_bytes(rs->requested_bitmap_chunk_sectors) ?: mddev->bitmap_info.chunksize;
 
         r = md_bitmap_resize(mddev->bitmap, mddev->dev_sectors, chunksize, 0);
         if (r)
             DMERR("Failed to resize bitmap");
     }
 
     /* Check for any resize/reshape on @rs and adjust/initiate */
     /* Be prepared for mddev_resume() in raid_resume() */
     set_bit(MD_RECOVERY_FROZEN, &mddev->recovery);
     if (mddev->recovery_cp && mddev->recovery_cp < MaxSector) {
         set_bit(MD_RECOVERY_REQUESTED, &mddev->recovery);
         mddev->resync_min = mddev->recovery_cp;
         if (test_bit(RT_FLAG_RS_GROW, &rs->runtime_flags))
             mddev->resync_max_sectors = mddev->dev_sectors;
     }
 
     /* Check for any reshape request unless new raid set */
     if (test_bit(RT_FLAG_RESHAPE_RS, &rs->runtime_flags)) {
         /* Initiate a reshape. */
         rs_set_rdev_sectors(rs);
         mddev_lock_nointr(mddev);
         r = rs_start_reshape(rs);
         mddev_unlock(mddev);
         if (r)
             DMWARN("Failed to check/start reshape, continuing without change");
         r = 0;
     }
 
     return r;
 }
 
 static void raid_resume(struct dm_target *ti)
 {
     struct raid_set *rs = ti->private;
     struct mddev *mddev = &rs->md;
 
     if (test_and_set_bit(RT_FLAG_RS_RESUMED, &rs->runtime_flags)) {
         /*
          * A secondary resume while the device is active.
          * Take this opportunity to check whether any failed
          * devices are reachable again.
          */
         attempt_restore_of_faulty_devices(rs);
     }
 
     if (test_and_clear_bit(RT_FLAG_RS_SUSPENDED, &rs->runtime_flags)) {
         /* Only reduce raid set size before running a disk removing reshape. */
         if (mddev->delta_disks < 0)
             rs_set_capacity(rs);
 
         mddev_lock_nointr(mddev);
         clear_bit(MD_RECOVERY_FROZEN, &mddev->recovery);
         mddev->ro = 0;
         mddev->in_sync = 0;
         mddev_resume(mddev);
         mddev_unlock(mddev);
     }
 }
 
 static struct target_type raid_target = {
     .name = "raid",
     .version = {1, 15, 1},
     .module = THIS_MODULE,
     .ctr = raid_ctr,
     .dtr = raid_dtr,
     .map = raid_map,
     .status = raid_status,
     .message = raid_message,
     .iterate_devices = raid_iterate_devices,
     .io_hints = raid_io_hints,
     .postsuspend = raid_postsuspend,
     .preresume = raid_preresume,
     .resume = raid_resume,
 };
 
 static int __init dm_raid_init(void)
 {
     DMINFO("Loading target version %u.%u.%u",
            raid_target.version[0],
            raid_target.version[1],
            raid_target.version[2]);
     return dm_register_target(&raid_target);
 }
 
 static void __exit dm_raid_exit(void)
 {
     dm_unregister_target(&raid_target);
 }
 
 module_init(dm_raid_init);
 module_exit(dm_raid_exit);
 
 module_param(devices_handle_discard_safely, bool, 0644);
 MODULE_PARM_DESC(devices_handle_discard_safely,
          "Set to Y if all devices in each array reliably return zeroes on reads from discarded regions");
 
 MODULE_DESCRIPTION(DM_NAME " raid0/1/10/4/5/6 target");
 MODULE_ALIAS("dm-raid0");
 MODULE_ALIAS("dm-raid1");
 MODULE_ALIAS("dm-raid10");
 MODULE_ALIAS("dm-raid4");
 MODULE_ALIAS("dm-raid5");
 MODULE_ALIAS("dm-raid6");
 MODULE_AUTHOR("Neil Brown <dm-devel@redhat.com>");
 MODULE_AUTHOR("Heinz Mauelshagen <dm-devel@redhat.com>");
 MODULE_LICENSE("GPL");