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dm-region-hash.h
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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, struct bio *bio);
82 
83 /*
84  * Region recovery control.
85  */
86 
87 /* Prepare some regions for recovery by starting to quiesce them. */
88 void dm_rh_recovery_prepare(struct dm_region_hash *rh);
89 
90 /* Try fetching a quiesced region for recovery. */
91 struct dm_region *dm_rh_recovery_start(struct dm_region_hash *rh);
92 
93 /* Report recovery end on a region. */
94 void dm_rh_recovery_end(struct dm_region *reg, int error);
95 
96 /* Returns number of regions with recovery work outstanding. */
97 int dm_rh_recovery_in_flight(struct dm_region_hash *rh);
98 
99 /* Start/stop recovery. */
100 void dm_rh_start_recovery(struct dm_region_hash *rh);
101 void dm_rh_stop_recovery(struct dm_region_hash *rh);
102 
103 #endif /* DM_REGION_HASH_H */
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