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Release 4.12 include/linux/dm-dirty-log.h

Directory: include/linux
 * Copyright (C) 2003 Sistina Software
 * Copyright (C) 2004-2008 Red Hat, Inc. All rights reserved.
 * Device-Mapper dirty region log.
 * This file is released under the LGPL.



#ifdef __KERNEL__

#include <linux/types.h>
#include <linux/device-mapper.h>

typedef sector_t region_t;

struct dm_dirty_log_type;

struct dm_dirty_log {
struct dm_dirty_log_type *type;
int (*flush_callback_fn)(struct dm_target *ti);
void *context;

struct dm_dirty_log_type {
const char *name;
struct module *module;

	/* For internal device-mapper use */
struct list_head list;

int (*ctr)(struct dm_dirty_log *log, struct dm_target *ti,
		   unsigned argc, char **argv);
void (*dtr)(struct dm_dirty_log *log);

         * There are times when we don't want the log to touch
         * the disk.
int (*presuspend)(struct dm_dirty_log *log);
int (*postsuspend)(struct dm_dirty_log *log);
int (*resume)(struct dm_dirty_log *log);

         * Retrieves the smallest size of region that the log can
         * deal with.
uint32_t (*get_region_size)(struct dm_dirty_log *log);

         * A predicate to say whether a region is clean or not.
         * May block.
int (*is_clean)(struct dm_dirty_log *log, region_t region);

         *  Returns: 0, 1, -EWOULDBLOCK, < 0
         * A predicate function to check the area given by
         * [sector, sector + len) is in sync.
         * If -EWOULDBLOCK is returned the state of the region is
         * unknown, typically this will result in a read being
         * passed to a daemon to deal with, since a daemon is
         * allowed to block.
int (*in_sync)(struct dm_dirty_log *log, region_t region,
		       int can_block);

         * Flush the current log state (eg, to disk).  This
         * function may block.
int (*flush)(struct dm_dirty_log *log);

         * Mark an area as clean or dirty.  These functions may
         * block, though for performance reasons blocking should
         * be extremely rare (eg, allocating another chunk of
         * memory for some reason).
void (*mark_region)(struct dm_dirty_log *log, region_t region);
void (*clear_region)(struct dm_dirty_log *log, region_t region);

         * Returns: <0 (error), 0 (no region), 1 (region)
         * The mirrord will need perform recovery on regions of
         * the mirror that are in the NOSYNC state.  This
         * function asks the log to tell the caller about the
         * next region that this machine should recover.
         * Do not confuse this function with 'in_sync()', one
         * tells you if an area is synchronised, the other
         * assigns recovery work.
int (*get_resync_work)(struct dm_dirty_log *log, region_t *region);

         * This notifies the log that the resync status of a region
         * has changed.  It also clears the region from the recovering
         * list (if present).
void (*set_region_sync)(struct dm_dirty_log *log,
				region_t region, int in_sync);

         * Returns the number of regions that are in sync.
region_t (*get_sync_count)(struct dm_dirty_log *log);

         * Support function for mirror status requests.
int (*status)(struct dm_dirty_log *log, status_type_t status_type,
		      char *result, unsigned maxlen);

         * is_remote_recovering is necessary for cluster mirroring. It provides
         * a way to detect recovery on another node, so we aren't writing
         * concurrently.  This function is likely to block (when a cluster log
         * is used).
         * Returns: 0, 1
int (*is_remote_recovering)(struct dm_dirty_log *log, region_t region);

int dm_dirty_log_type_register(struct dm_dirty_log_type *type);
int dm_dirty_log_type_unregister(struct dm_dirty_log_type *type);

 * Make sure you use these two functions, rather than calling
 * type->constructor/destructor() directly.
struct dm_dirty_log *dm_dirty_log_create(const char *type_name,
			struct dm_target *ti,
			int (*flush_callback_fn)(struct dm_target *ti),
			unsigned argc, char **argv);
void dm_dirty_log_destroy(struct dm_dirty_log *log);

#endif	/* __KERNEL__ */
#endif	/* _LINUX_DM_DIRTY_LOG_H */

Overall Contributors

Alasdair G. Kergon29174.05%333.33%
Heinz Mauelshagen4210.69%111.11%
Jonathan E Brassow317.89%333.33%
Mikulas Patocka246.11%111.11%
Mike Snitzer51.27%111.11%
Directory: include/linux
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