drivers/md/raid1.h

   1 #ifndef _RAID1_H
   2 #define _RAID1_H
   3
   4 typedef struct mirror_info mirror_info_t;
   5
   6 struct mirror_info {
   7         struct md_rdev  *rdev;
   8         sector_t        head_position;
   9 };
  10
  11 /*
  12  * memory pools need a pointer to the mddev, so they can force an unplug
  13  * when memory is tight, and a count of the number of drives that the
  14  * pool was allocated for, so they know how much to allocate and free.
  15  * mddev->raid_disks cannot be used, as it can change while a pool is active
  16  * These two datums are stored in a kmalloced struct.
  17  */
  18
  19 struct pool_info {
  20         mddev_t *mddev;
  21         int     raid_disks;
  22 };
  23
  24
  25 typedef struct r1bio_s r1bio_t;
  26
  27 struct r1_private_data_s {
  28         mddev_t                 *mddev;
  29         mirror_info_t           *mirrors;
  30         int                     raid_disks;
  31
  32         /* When choose the best device for a read (read_balance())
  33          * we try to keep sequential reads one the same device
  34          * using 'last_used' and 'next_seq_sect'
  35          */
  36         int                     last_used;
  37         sector_t                next_seq_sect;
  38         /* During resync, read_balancing is only allowed on the part
  39          * of the array that has been resynced.  'next_resync' tells us
  40          * where that is.
  41          */
  42         sector_t                next_resync;
  43
  44         spinlock_t              device_lock;
  45
  46         /* list of 'r1bio_t' that need to be processed by raid1d, whether
  47          * to retry a read, writeout a resync or recovery block, or
  48          * anything else.
  49          */
  50         struct list_head        retry_list;
  51
  52         /* queue pending writes to be submitted on unplug */
  53         struct bio_list         pending_bio_list;
  54
  55         /* for use when syncing mirrors:
  56          * We don't allow both normal IO and resync/recovery IO at
  57          * the same time - resync/recovery can only happen when there
  58          * is no other IO.  So when either is active, the other has to wait.
  59          * See more details description in raid1.c near raise_barrier().
  60          */
  61         wait_queue_head_t       wait_barrier;
  62         spinlock_t              resync_lock;
  63         int                     nr_pending;
  64         int                     nr_waiting;
  65         int                     nr_queued;
  66         int                     barrier;
  67
  68         /* Set to 1 if a full sync is needed, (fresh device added).
  69          * Cleared when a sync completes.
  70          */
  71         int                     fullsync;
  72
  73         /* When the same as mddev->recovery_disabled we don't allow
  74          * recovery to be attempted as we expect a read error.
  75          */
  76         int                     recovery_disabled;
  77
  78
  79         /* poolinfo contains information about the content of the
  80          * mempools - it changes when the array grows or shrinks
  81          */
  82         struct pool_info        *poolinfo;
  83         mempool_t *r1bio_pool;
  84         mempool_t *r1buf_pool;
  85
  86         /* temporary buffer to synchronous IO when attempting to repair
  87          * a read error.
  88          */
  89         struct page             *tmppage;
  90
  91
  92         /* When taking over an array from a different personality, we store
  93          * the new thread here until we fully activate the array.
  94          */
  95         struct mdk_thread_s     *thread;
  96 };
  97
  98 typedef struct r1_private_data_s conf_t;
  99
 100 /*
 101  * this is our 'private' RAID1 bio.
 102  *
 103  * it contains information about what kind of IO operations were started
 104  * for this RAID1 operation, and about their status:
 105  */
 106
 107 struct r1bio_s {
 108         atomic_t                remaining; /* 'have we finished' count,
 109                                             * used from IRQ handlers
 110                                             */
 111         atomic_t                behind_remaining; /* number of write-behind ios remaining
 112                                                  * in this BehindIO request
 113                                                  */
 114         sector_t                sector;
 115         int                     sectors;
 116         unsigned long           state;
 117         mddev_t                 *mddev;
 118         /*
 119          * original bio going to /dev/mdx
 120          */
 121         struct bio              *master_bio;
 122         /*
 123          * if the IO is in READ direction, then this is where we read
 124          */
 125         int                     read_disk;
 126
 127         struct list_head        retry_list;
 128         /* Next two are only valid when R1BIO_BehindIO is set */
 129         struct bio_vec          *behind_bvecs;
 130         int                     behind_page_count;
 131         /*
 132          * if the IO is in WRITE direction, then multiple bios are used.
 133          * We choose the number when they are allocated.
 134          */
 135         struct bio              *bios[0];
 136         /* DO NOT PUT ANY NEW FIELDS HERE - bios array is contiguously alloced*/
 137 };
 138
 139 /* when we get a read error on a read-only array, we redirect to another
 140  * device without failing the first device, or trying to over-write to
 141  * correct the read error.  To keep track of bad blocks on a per-bio
 142  * level, we store IO_BLOCKED in the appropriate 'bios' pointer
 143  */
 144 #define IO_BLOCKED ((struct bio *)1)
 145 /* When we successfully write to a known bad-block, we need to remove the
 146  * bad-block marking which must be done from process context.  So we record
 147  * the success by setting bios[n] to IO_MADE_GOOD
 148  */
 149 #define IO_MADE_GOOD ((struct bio *)2)
 150
 151 #define BIO_SPECIAL(bio) ((unsigned long)bio <= 2)
 152
 153 /* bits for r1bio.state */
 154 #define R1BIO_Uptodate  0
 155 #define R1BIO_IsSync    1
 156 #define R1BIO_Degraded  2
 157 #define R1BIO_BehindIO  3
 158 /* Set ReadError on bios that experience a readerror so that
 159  * raid1d knows what to do with them.
 160  */
 161 #define R1BIO_ReadError 4
 162 /* For write-behind requests, we call bi_end_io when
 163  * the last non-write-behind device completes, providing
 164  * any write was successful.  Otherwise we call when
 165  * any write-behind write succeeds, otherwise we call
 166  * with failure when last write completes (and all failed).
 167  * Record that bi_end_io was called with this flag...
 168  */
 169 #define R1BIO_Returned 6
 170 /* If a write for this request means we can clear some
 171  * known-bad-block records, we set this flag
 172  */
 173 #define R1BIO_MadeGood 7
 174 #define R1BIO_WriteError 8
 175
 176 extern int md_raid1_congested(mddev_t *mddev, int bits);
 177
 178 #endif