include/linux/dm-region-hash.h

   1 /*
   2  * Copyright (C) 2003 Sistina Software Limited.
   3  * Copyright (C) 2004-2008 Red Hat, Inc. All rights reserved.
   4  *
   5  * Device-Mapper dirty region hash interface.
   6  *
   7  * This file is released under the GPL.
   8  */
   9
  10 #ifndef DM_REGION_HASH_H
  11 #define DM_REGION_HASH_H
  12
  13 #include <linux/dm-dirty-log.h>
  14
  15 /*-----------------------------------------------------------------
  16  * Region hash
  17  *----------------------------------------------------------------*/
  18 struct dm_region_hash;
  19 struct dm_region;
  20
  21 /*
  22  * States a region can have.
  23  */
  24 enum dm_rh_region_states {
  25         DM_RH_CLEAN      = 0x01,        /* No writes in flight. */
  26         DM_RH_DIRTY      = 0x02,        /* Writes in flight. */
  27         DM_RH_NOSYNC     = 0x04,        /* Out of sync. */
  28         DM_RH_RECOVERING = 0x08,        /* Under resynchronization. */
  29 };
  30
  31 /*
  32  * Region hash create/destroy.
  33  */
  34 struct bio_list;
  35 struct dm_region_hash *dm_region_hash_create(
  36                 void *context, void (*dispatch_bios)(void *context,
  37                                                      struct bio_list *bios),
  38                 void (*wakeup_workers)(void *context),
  39                 void (*wakeup_all_recovery_waiters)(void *context),
  40                 sector_t target_begin, unsigned max_recovery,
  41                 struct dm_dirty_log *log, uint32_t region_size,
  42                 region_t nr_regions);
  43 void dm_region_hash_destroy(struct dm_region_hash *rh);
  44
  45 struct dm_dirty_log *dm_rh_dirty_log(struct dm_region_hash *rh);
  46
  47 /*
  48  * Conversion functions.
  49  */
  50 region_t dm_rh_bio_to_region(struct dm_region_hash *rh, struct bio *bio);
  51 sector_t dm_rh_region_to_sector(struct dm_region_hash *rh, region_t region);
  52 void *dm_rh_region_context(struct dm_region *reg);
  53
  54 /*
  55  * Get region size and key (ie. number of the region).
  56  */
  57 sector_t dm_rh_get_region_size(struct dm_region_hash *rh);
  58 region_t dm_rh_get_region_key(struct dm_region *reg);
  59
  60 /*
  61  * Get/set/update region state (and dirty log).
  62  *
  63  */
  64 int dm_rh_get_state(struct dm_region_hash *rh, region_t region, int may_block);
  65 void dm_rh_set_state(struct dm_region_hash *rh, region_t region,
  66                      enum dm_rh_region_states state, int may_block);
  67
  68 /* Non-zero errors_handled leaves the state of the region NOSYNC */
  69 void dm_rh_update_states(struct dm_region_hash *rh, int errors_handled);
  70
  71 /* Flush the region hash and dirty log. */
  72 int dm_rh_flush(struct dm_region_hash *rh);
  73
  74 /* Inc/dec pending count on regions. */
  75 void dm_rh_inc_pending(struct dm_region_hash *rh, struct bio_list *bios);
  76 void dm_rh_dec(struct dm_region_hash *rh, region_t region);
  77
  78 /* Delay bios on regions. */
  79 void dm_rh_delay(struct dm_region_hash *rh, struct bio *bio);
  80
  81 void dm_rh_mark_nosync(struct dm_region_hash *rh,
  82                        struct bio *bio, unsigned done, int error);
  83
  84 /*
  85  * Region recovery control.
  86  */
  87
  88 /* Prepare some regions for recovery by starting to quiesce them. */
  89 void dm_rh_recovery_prepare(struct dm_region_hash *rh);
  90
  91 /* Try fetching a quiesced region for recovery. */
  92 struct dm_region *dm_rh_recovery_start(struct dm_region_hash *rh);
  93
  94 /* Report recovery end on a region. */
  95 void dm_rh_recovery_end(struct dm_region *reg, int error);
  96
  97 /* Returns number of regions with recovery work outstanding. */
  98 int dm_rh_recovery_in_flight(struct dm_region_hash *rh);
  99
 100 /* Start/stop recovery. */
 101 void dm_rh_start_recovery(struct dm_region_hash *rh);
 102 void dm_rh_stop_recovery(struct dm_region_hash *rh);
 103
 104 #endif /* DM_REGION_HASH_H */