drivers/md/raid10.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 #ifndef _RAID10_H
   3 #define _RAID10_H
   4
   5 /* Note: raid10_info.rdev can be set to NULL asynchronously by
   6  * raid10_remove_disk.
   7  * There are three safe ways to access raid10_info.rdev.
   8  * 1/ when holding mddev->reconfig_mutex
   9  * 2/ when resync/recovery/reshape is known to be happening - i.e. in code
  10  *    that is called as part of performing resync/recovery/reshape.
  11  * 3/ while holding rcu_read_lock(), use rcu_dereference to get the pointer
  12  *    and if it is non-NULL, increment rdev->nr_pending before dropping the
  13  *    RCU lock.
  14  * When .rdev is set to NULL, the nr_pending count checked again and if it has
  15  * been incremented, the pointer is put back in .rdev.
  16  */
  17
  18 struct raid10_info {
  19         struct md_rdev  *rdev, *replacement;
  20         sector_t        head_position;
  21         int             recovery_disabled;      /* matches
  22                                                  * mddev->recovery_disabled
  23                                                  * when we shouldn't try
  24                                                  * recovering this device.
  25                                                  */
  26 };
  27
  28 struct r10conf {
  29         struct mddev            *mddev;
  30         struct raid10_info      *mirrors;
  31         struct raid10_info      *mirrors_new, *mirrors_old;
  32         spinlock_t              device_lock;
  33
  34         /* geometry */
  35         struct geom {
  36                 int             raid_disks;
  37                 int             near_copies;  /* number of copies laid out
  38                                                * raid0 style */
  39                 int             far_copies;   /* number of copies laid out
  40                                                * at large strides across drives
  41                                                */
  42                 int             far_offset;   /* far_copies are offset by 1
  43                                                * stripe instead of many
  44                                                */
  45                 sector_t        stride;       /* distance between far copies.
  46                                                * This is size / far_copies unless
  47                                                * far_offset, in which case it is
  48                                                * 1 stripe.
  49                                                */
  50                 int             far_set_size; /* The number of devices in a set,
  51                                                * where a 'set' are devices that
  52                                                * contain far/offset copies of
  53                                                * each other.
  54                                                */
  55                 int             chunk_shift; /* shift from chunks to sectors */
  56                 sector_t        chunk_mask;
  57         } prev, geo;
  58         int                     copies;       /* near_copies * far_copies.
  59                                                * must be <= raid_disks
  60                                                */
  61
  62         sector_t                dev_sectors;  /* temp copy of
  63                                                * mddev->dev_sectors */
  64         sector_t                reshape_progress;
  65         sector_t                reshape_safe;
  66         unsigned long           reshape_checkpoint;
  67         sector_t                offset_diff;
  68
  69         struct list_head        retry_list;
  70         /* A separate list of r1bio which just need raid_end_bio_io called.
  71          * This mustn't happen for writes which had any errors if the superblock
  72          * needs to be written.
  73          */
  74         struct list_head        bio_end_io_list;
  75
  76         /* queue pending writes and submit them on unplug */
  77         struct bio_list         pending_bio_list;
  78
  79         seqlock_t               resync_lock;
  80         atomic_t                nr_pending;
  81         int                     nr_waiting;
  82         int                     nr_queued;
  83         int                     barrier;
  84         int                     array_freeze_pending;
  85         sector_t                next_resync;
  86         int                     fullsync;  /* set to 1 if a full sync is needed,
  87                                             * (fresh device added).
  88                                             * Cleared when a sync completes.
  89                                             */
  90         int                     have_replacement; /* There is at least one
  91                                                    * replacement device.
  92                                                    */
  93         wait_queue_head_t       wait_barrier;
  94
  95         mempool_t               r10bio_pool;
  96         mempool_t               r10buf_pool;
  97         struct page             *tmppage;
  98         struct bio_set          bio_split;
  99
 100         /* When taking over an array from a different personality, we store
 101          * the new thread here until we fully activate the array.
 102          */
 103         struct md_thread __rcu  *thread;
 104
 105         /*
 106          * Keep track of cluster resync window to send to other nodes.
 107          */
 108         sector_t                cluster_sync_low;
 109         sector_t                cluster_sync_high;
 110 };
 111
 112 /*
 113  * this is our 'private' RAID10 bio.
 114  *
 115  * it contains information about what kind of IO operations were started
 116  * for this RAID10 operation, and about their status:
 117  */
 118
 119 struct r10bio {
 120         atomic_t                remaining; /* 'have we finished' count,
 121                                             * used from IRQ handlers
 122                                             */
 123         sector_t                sector; /* virtual sector number */
 124         int                     sectors;
 125         unsigned long           state;
 126         struct mddev            *mddev;
 127         /*
 128          * original bio going to /dev/mdx
 129          */
 130         struct bio              *master_bio;
 131         /*
 132          * if the IO is in READ direction, then this is where we read
 133          */
 134         int                     read_slot;
 135
 136         struct list_head        retry_list;
 137         /*
 138          * if the IO is in WRITE direction, then multiple bios are used,
 139          * one for each copy.
 140          * When resyncing we also use one for each copy.
 141          * When reconstructing, we use 2 bios, one for read, one for write.
 142          * We choose the number when they are allocated.
 143          * We sometimes need an extra bio to write to the replacement.
 144          */
 145         struct r10dev {
 146                 struct bio      *bio;
 147                 union {
 148                         struct bio      *repl_bio; /* used for resync and
 149                                                     * writes */
 150                         struct md_rdev  *rdev;     /* used for reads
 151                                                     * (read_slot >= 0) */
 152                 };
 153                 sector_t        addr;
 154                 int             devnum;
 155         } devs[];
 156 };
 157
 158 /* bits for r10bio.state */
 159 enum r10bio_state {
 160         R10BIO_Uptodate,
 161         R10BIO_IsSync,
 162         R10BIO_IsRecover,
 163         R10BIO_IsReshape,
 164         R10BIO_Degraded,
 165 /* Set ReadError on bios that experience a read error
 166  * so that raid10d knows what to do with them.
 167  */
 168         R10BIO_ReadError,
 169 /* If a write for this request means we can clear some
 170  * known-bad-block records, we set this flag.
 171  */
 172         R10BIO_MadeGood,
 173         R10BIO_WriteError,
 174 /* During a reshape we might be performing IO on the
 175  * 'previous' part of the array, in which case this
 176  * flag is set
 177  */
 178         R10BIO_Previous,
 179 /* failfast devices did receive failfast requests. */
 180         R10BIO_FailFast,
 181         R10BIO_Discard,
 182 };
 183 #endif