1 /* SPDX-License-Identifier: GPL-2.0-only */
2 /*
3  * Copyright (C) 2003 Sistina Software Limited.
4  * Copyright (C) 2004-2008 Red Hat, Inc. All rights reserved.
5  *
6  * Device-Mapper dirty region hash interface.
7  *
8  * This file is released under the GPL.
9  */
10 
11 #ifndef DM_REGION_HASH_H
12 #define DM_REGION_HASH_H
13 
14 #include <linux/dm-dirty-log.h>
15 
16 /*
17  *----------------------------------------------------------------
18  * Region hash
19  *----------------------------------------------------------------
20  */
21 struct dm_region_hash;
22 struct dm_region;
23 
24 /*
25  * States a region can have.
26  */
27 enum dm_rh_region_states {
28 	DM_RH_CLEAN	 = 0x01,	/* No writes in flight. */
29 	DM_RH_DIRTY	 = 0x02,	/* Writes in flight. */
30 	DM_RH_NOSYNC	 = 0x04,	/* Out of sync. */
31 	DM_RH_RECOVERING = 0x08,	/* Under resynchronization. */
32 };
33 
34 /*
35  * Region hash create/destroy.
36  */
37 struct bio_list;
38 struct dm_region_hash *dm_region_hash_create(
39 		void *context, void (*dispatch_bios)(void *context,
40 						     struct bio_list *bios),
41 		void (*wakeup_workers)(void *context),
42 		void (*wakeup_all_recovery_waiters)(void *context),
43 		sector_t target_begin, unsigned int max_recovery,
44 		struct dm_dirty_log *log, uint32_t region_size,
45 		region_t nr_regions);
46 void dm_region_hash_destroy(struct dm_region_hash *rh);
47 
48 struct dm_dirty_log *dm_rh_dirty_log(struct dm_region_hash *rh);
49 
50 /*
51  * Conversion functions.
52  */
53 region_t dm_rh_bio_to_region(struct dm_region_hash *rh, struct bio *bio);
54 sector_t dm_rh_region_to_sector(struct dm_region_hash *rh, region_t region);
55 void *dm_rh_region_context(struct dm_region *reg);
56 
57 /*
58  * Get region size and key (ie. number of the region).
59  */
60 sector_t dm_rh_get_region_size(struct dm_region_hash *rh);
61 region_t dm_rh_get_region_key(struct dm_region *reg);
62 
63 /*
64  * Get/set/update region state (and dirty log).
65  *
66  */
67 int dm_rh_get_state(struct dm_region_hash *rh, region_t region, int may_block);
68 void dm_rh_set_state(struct dm_region_hash *rh, region_t region,
69 		     enum dm_rh_region_states state, int may_block);
70 
71 /* Non-zero errors_handled leaves the state of the region NOSYNC */
72 void dm_rh_update_states(struct dm_region_hash *rh, int errors_handled);
73 
74 /* Flush the region hash and dirty log. */
75 int dm_rh_flush(struct dm_region_hash *rh);
76 
77 /* Inc/dec pending count on regions. */
78 void dm_rh_inc_pending(struct dm_region_hash *rh, struct bio_list *bios);
79 void dm_rh_dec(struct dm_region_hash *rh, region_t region);
80 
81 /* Delay bios on regions. */
82 void dm_rh_delay(struct dm_region_hash *rh, struct bio *bio);
83 
84 void dm_rh_mark_nosync(struct dm_region_hash *rh, struct bio *bio);
85 
86 /*
87  * Region recovery control.
88  */
89 
90 /* Prepare some regions for recovery by starting to quiesce them. */
91 void dm_rh_recovery_prepare(struct dm_region_hash *rh);
92 
93 /* Try fetching a quiesced region for recovery. */
94 struct dm_region *dm_rh_recovery_start(struct dm_region_hash *rh);
95 
96 /* Report recovery end on a region. */
97 void dm_rh_recovery_end(struct dm_region *reg, int error);
98 
99 /* Returns number of regions with recovery work outstanding. */
100 int dm_rh_recovery_in_flight(struct dm_region_hash *rh);
101 
102 /* Start/stop recovery. */
103 void dm_rh_start_recovery(struct dm_region_hash *rh);
104 void dm_rh_stop_recovery(struct dm_region_hash *rh);
105 
106 #endif /* DM_REGION_HASH_H */
107