1/* 2 * Copyright (C) 2003 Sistina Software 3 * 4 * This file is released under the LGPL. 5 */ 6 7#ifndef DM_DIRTY_LOG 8#define DM_DIRTY_LOG 9 10#include "dm.h" 11 12typedef sector_t region_t; 13 14struct dirty_log_type; 15 16struct dirty_log { 17 struct dirty_log_type *type; 18 void *context; 19}; 20 21struct dirty_log_type { 22 struct list_head list; 23 const char *name; 24 struct module *module; 25 unsigned int use_count; 26 27 int (*ctr)(struct dirty_log *log, struct dm_target *ti, 28 unsigned int argc, char **argv); 29 void (*dtr)(struct dirty_log *log); 30 31 /* 32 * There are times when we don't want the log to touch 33 * the disk. 34 */ 35 int (*suspend)(struct dirty_log *log); 36 int (*resume)(struct dirty_log *log); 37 38 /* 39 * Retrieves the smallest size of region that the log can 40 * deal with. 41 */ 42 uint32_t (*get_region_size)(struct dirty_log *log); 43 44 /* 45 * A predicate to say whether a region is clean or not. 46 * May block. 47 */ 48 int (*is_clean)(struct dirty_log *log, region_t region); 49 50 /* 51 * Returns: 0, 1, -EWOULDBLOCK, < 0 52 * 53 * A predicate function to check the area given by 54 * [sector, sector + len) is in sync. 55 * 56 * If -EWOULDBLOCK is returned the state of the region is 57 * unknown, typically this will result in a read being 58 * passed to a daemon to deal with, since a daemon is 59 * allowed to block. 60 */ 61 int (*in_sync)(struct dirty_log *log, region_t region, int can_block); 62 63 /* 64 * Flush the current log state (eg, to disk). This 65 * function may block. 66 */ 67 int (*flush)(struct dirty_log *log); 68 69 /* 70 * Mark an area as clean or dirty. These functions may 71 * block, though for performance reasons blocking should 72 * be extremely rare (eg, allocating another chunk of 73 * memory for some reason). 74 */ 75 void (*mark_region)(struct dirty_log *log, region_t region); 76 void (*clear_region)(struct dirty_log *log, region_t region); 77 78 /* 79 * Returns: <0 (error), 0 (no region), 1 (region) 80 * 81 * The mirrord will need perform recovery on regions of 82 * the mirror that are in the NOSYNC state. This 83 * function asks the log to tell the caller about the 84 * next region that this machine should recover. 85 * 86 * Do not confuse this function with 'in_sync()', one 87 * tells you if an area is synchronised, the other 88 * assigns recovery work. 89 */ 90 int (*get_resync_work)(struct dirty_log *log, region_t *region); 91 92 /* 93 * This notifies the log that the resync status of a region 94 * has changed. It also clears the region from the recovering 95 * list (if present). 96 */ 97 void (*set_region_sync)(struct dirty_log *log, 98 region_t region, int in_sync); 99 100 /* 101 * Returns the number of regions that are in sync. 102 */ 103 region_t (*get_sync_count)(struct dirty_log *log); 104 105 /* 106 * Support function for mirror status requests. 107 */ 108 int (*status)(struct dirty_log *log, status_type_t status_type, 109 char *result, unsigned int maxlen); 110}; 111 112int dm_register_dirty_log_type(struct dirty_log_type *type); 113int dm_unregister_dirty_log_type(struct dirty_log_type *type); 114 115 116/* 117 * Make sure you use these two functions, rather than calling 118 * type->constructor/destructor() directly. 119 */ 120struct dirty_log *dm_create_dirty_log(const char *type_name, struct dm_target *ti, 121 unsigned int argc, char **argv); 122void dm_destroy_dirty_log(struct dirty_log *log); 123 124/* 125 * init/exit functions. 126 */ 127int dm_dirty_log_init(void); 128void dm_dirty_log_exit(void); 129 130#endif 131