linux/drivers/md/raid10.h
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   1/* SPDX-License-Identifier: GPL-2.0 */
   2#ifndef _RAID10_H
   3#define _RAID10_H
   4
   5struct raid10_info {
   6        struct md_rdev  *rdev, *replacement;
   7        sector_t        head_position;
   8        int             recovery_disabled;      /* matches
   9                                                 * mddev->recovery_disabled
  10                                                 * when we shouldn't try
  11                                                 * recovering this device.
  12                                                 */
  13};
  14
  15struct r10conf {
  16        struct mddev            *mddev;
  17        struct raid10_info      *mirrors;
  18        struct raid10_info      *mirrors_new, *mirrors_old;
  19        spinlock_t              device_lock;
  20
  21        /* geometry */
  22        struct geom {
  23                int             raid_disks;
  24                int             near_copies;  /* number of copies laid out
  25                                               * raid0 style */
  26                int             far_copies;   /* number of copies laid out
  27                                               * at large strides across drives
  28                                               */
  29                int             far_offset;   /* far_copies are offset by 1
  30                                               * stripe instead of many
  31                                               */
  32                sector_t        stride;       /* distance between far copies.
  33                                               * This is size / far_copies unless
  34                                               * far_offset, in which case it is
  35                                               * 1 stripe.
  36                                               */
  37                int             far_set_size; /* The number of devices in a set,
  38                                               * where a 'set' are devices that
  39                                               * contain far/offset copies of
  40                                               * each other.
  41                                               */
  42                int             chunk_shift; /* shift from chunks to sectors */
  43                sector_t        chunk_mask;
  44        } prev, geo;
  45        int                     copies;       /* near_copies * far_copies.
  46                                               * must be <= raid_disks
  47                                               */
  48
  49        sector_t                dev_sectors;  /* temp copy of
  50                                               * mddev->dev_sectors */
  51        sector_t                reshape_progress;
  52        sector_t                reshape_safe;
  53        unsigned long           reshape_checkpoint;
  54        sector_t                offset_diff;
  55
  56        struct list_head        retry_list;
  57        /* A separate list of r1bio which just need raid_end_bio_io called.
  58         * This mustn't happen for writes which had any errors if the superblock
  59         * needs to be written.
  60         */
  61        struct list_head        bio_end_io_list;
  62
  63        /* queue pending writes and submit them on unplug */
  64        struct bio_list         pending_bio_list;
  65        int                     pending_count;
  66
  67        spinlock_t              resync_lock;
  68        atomic_t                nr_pending;
  69        int                     nr_waiting;
  70        int                     nr_queued;
  71        int                     barrier;
  72        int                     array_freeze_pending;
  73        sector_t                next_resync;
  74        int                     fullsync;  /* set to 1 if a full sync is needed,
  75                                            * (fresh device added).
  76                                            * Cleared when a sync completes.
  77                                            */
  78        int                     have_replacement; /* There is at least one
  79                                                   * replacement device.
  80                                                   */
  81        wait_queue_head_t       wait_barrier;
  82
  83        mempool_t               *r10bio_pool;
  84        mempool_t               *r10buf_pool;
  85        struct page             *tmppage;
  86        struct bio_set          *bio_split;
  87
  88        /* When taking over an array from a different personality, we store
  89         * the new thread here until we fully activate the array.
  90         */
  91        struct md_thread        *thread;
  92};
  93
  94/*
  95 * this is our 'private' RAID10 bio.
  96 *
  97 * it contains information about what kind of IO operations were started
  98 * for this RAID10 operation, and about their status:
  99 */
 100
 101struct r10bio {
 102        atomic_t                remaining; /* 'have we finished' count,
 103                                            * used from IRQ handlers
 104                                            */
 105        sector_t                sector; /* virtual sector number */
 106        int                     sectors;
 107        unsigned long           state;
 108        struct mddev            *mddev;
 109        /*
 110         * original bio going to /dev/mdx
 111         */
 112        struct bio              *master_bio;
 113        /*
 114         * if the IO is in READ direction, then this is where we read
 115         */
 116        int                     read_slot;
 117
 118        struct list_head        retry_list;
 119        /*
 120         * if the IO is in WRITE direction, then multiple bios are used,
 121         * one for each copy.
 122         * When resyncing we also use one for each copy.
 123         * When reconstructing, we use 2 bios, one for read, one for write.
 124         * We choose the number when they are allocated.
 125         * We sometimes need an extra bio to write to the replacement.
 126         */
 127        struct r10dev {
 128                struct bio      *bio;
 129                union {
 130                        struct bio      *repl_bio; /* used for resync and
 131                                                    * writes */
 132                        struct md_rdev  *rdev;     /* used for reads
 133                                                    * (read_slot >= 0) */
 134                };
 135                sector_t        addr;
 136                int             devnum;
 137        } devs[0];
 138};
 139
 140/* bits for r10bio.state */
 141enum r10bio_state {
 142        R10BIO_Uptodate,
 143        R10BIO_IsSync,
 144        R10BIO_IsRecover,
 145        R10BIO_IsReshape,
 146        R10BIO_Degraded,
 147/* Set ReadError on bios that experience a read error
 148 * so that raid10d knows what to do with them.
 149 */
 150        R10BIO_ReadError,
 151/* If a write for this request means we can clear some
 152 * known-bad-block records, we set this flag.
 153 */
 154        R10BIO_MadeGood,
 155        R10BIO_WriteError,
 156/* During a reshape we might be performing IO on the
 157 * 'previous' part of the array, in which case this
 158 * flag is set
 159 */
 160        R10BIO_Previous,
 161/* failfast devices did receive failfast requests. */
 162        R10BIO_FailFast,
 163};
 164#endif
 165