131 lines
3.3 KiB
C
131 lines
3.3 KiB
C
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/*
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* Copyright (C) 2003 Sistina Software
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*
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* This file is released under the LGPL.
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*/
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#ifndef DM_DIRTY_LOG
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#define DM_DIRTY_LOG
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#include "dm.h"
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typedef sector_t region_t;
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struct dirty_log_type;
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struct dirty_log {
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struct dirty_log_type *type;
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void *context;
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};
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struct dirty_log_type {
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struct list_head list;
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const char *name;
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struct module *module;
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unsigned int use_count;
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int (*ctr)(struct dirty_log *log, struct dm_target *ti,
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unsigned int argc, char **argv);
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void (*dtr)(struct dirty_log *log);
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/*
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* There are times when we don't want the log to touch
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* the disk.
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*/
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int (*suspend)(struct dirty_log *log);
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int (*resume)(struct dirty_log *log);
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/*
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* Retrieves the smallest size of region that the log can
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* deal with.
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*/
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uint32_t (*get_region_size)(struct dirty_log *log);
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/*
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* A predicate to say whether a region is clean or not.
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* May block.
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*/
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int (*is_clean)(struct dirty_log *log, region_t region);
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/*
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* Returns: 0, 1, -EWOULDBLOCK, < 0
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*
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* A predicate function to check the area given by
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* [sector, sector + len) is in sync.
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*
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* If -EWOULDBLOCK is returned the state of the region is
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* unknown, typically this will result in a read being
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* passed to a daemon to deal with, since a daemon is
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* allowed to block.
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*/
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int (*in_sync)(struct dirty_log *log, region_t region, int can_block);
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/*
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* Flush the current log state (eg, to disk). This
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* function may block.
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*/
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int (*flush)(struct dirty_log *log);
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/*
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* Mark an area as clean or dirty. These functions may
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* block, though for performance reasons blocking should
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* be extremely rare (eg, allocating another chunk of
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* memory for some reason).
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*/
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void (*mark_region)(struct dirty_log *log, region_t region);
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void (*clear_region)(struct dirty_log *log, region_t region);
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/*
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* Returns: <0 (error), 0 (no region), 1 (region)
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*
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* The mirrord will need perform recovery on regions of
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* the mirror that are in the NOSYNC state. This
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* function asks the log to tell the caller about the
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* next region that this machine should recover.
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*
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* Do not confuse this function with 'in_sync()', one
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* tells you if an area is synchronised, the other
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* assigns recovery work.
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*/
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int (*get_resync_work)(struct dirty_log *log, region_t *region);
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/*
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* This notifies the log that the resync of an area has
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* been completed. The log should then mark this region
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* as CLEAN.
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*/
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void (*complete_resync_work)(struct dirty_log *log,
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region_t region, int success);
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/*
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* Returns the number of regions that are in sync.
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*/
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region_t (*get_sync_count)(struct dirty_log *log);
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/*
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* Support function for mirror status requests.
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*/
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int (*status)(struct dirty_log *log, status_type_t status_type,
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char *result, unsigned int maxlen);
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};
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int dm_register_dirty_log_type(struct dirty_log_type *type);
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int dm_unregister_dirty_log_type(struct dirty_log_type *type);
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/*
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* Make sure you use these two functions, rather than calling
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* type->constructor/destructor() directly.
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*/
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struct dirty_log *dm_create_dirty_log(const char *type_name, struct dm_target *ti,
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unsigned int argc, char **argv);
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void dm_destroy_dirty_log(struct dirty_log *log);
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/*
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* init/exit functions.
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*/
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int dm_dirty_log_init(void);
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void dm_dirty_log_exit(void);
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#endif
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