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include/linux/dm-dirty-log.h
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/* * Copyright (C) 2003 Sistina Software |
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* Copyright (C) 2004-2008 Red Hat, Inc. All rights reserved. * * Device-Mapper dirty region log. |
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* * This file is released under the LGPL. */ |
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#ifndef _LINUX_DM_DIRTY_LOG #define _LINUX_DM_DIRTY_LOG #ifdef __KERNEL__ |
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#include <linux/types.h> #include <linux/device-mapper.h> |
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typedef sector_t region_t; |
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struct dm_dirty_log_type; |
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struct dm_dirty_log { struct dm_dirty_log_type *type; |
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int (*flush_callback_fn)(struct dm_target *ti); |
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void *context; }; |
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struct dm_dirty_log_type { |
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const char *name; struct module *module; |
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/* For internal device-mapper use */ struct list_head list; |
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int (*ctr)(struct dm_dirty_log *log, struct dm_target *ti, unsigned argc, char **argv); void (*dtr)(struct dm_dirty_log *log); |
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/* * There are times when we don't want the log to touch * the disk. */ |
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int (*presuspend)(struct dm_dirty_log *log); int (*postsuspend)(struct dm_dirty_log *log); int (*resume)(struct dm_dirty_log *log); |
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/* * Retrieves the smallest size of region that the log can * deal with. */ |
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uint32_t (*get_region_size)(struct dm_dirty_log *log); |
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/* |
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* A predicate to say whether a region is clean or not. * May block. */ |
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int (*is_clean)(struct dm_dirty_log *log, region_t region); |
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/* * 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. */ |
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int (*in_sync)(struct dm_dirty_log *log, region_t region, int can_block); |
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/* * Flush the current log state (eg, to disk). This * function may block. */ |
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int (*flush)(struct dm_dirty_log *log); |
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/* * 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). */ |
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void (*mark_region)(struct dm_dirty_log *log, region_t region); void (*clear_region)(struct dm_dirty_log *log, region_t region); |
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/* * 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. */ |
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int (*get_resync_work)(struct dm_dirty_log *log, region_t *region); |
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/* |
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* This notifies the log that the resync status of a region * has changed. It also clears the region from the recovering * list (if present). |
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*/ |
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void (*set_region_sync)(struct dm_dirty_log *log, |
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region_t region, int in_sync); |
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/* |
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* Returns the number of regions that are in sync. |
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*/ region_t (*get_sync_count)(struct dm_dirty_log *log); |
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/* * Support function for mirror status requests. */ |
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int (*status)(struct dm_dirty_log *log, status_type_t status_type, char *result, unsigned maxlen); |
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/* * 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); |
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}; |
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int dm_dirty_log_type_register(struct dm_dirty_log_type *type); int dm_dirty_log_type_unregister(struct dm_dirty_log_type *type); |
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/* * Make sure you use these two functions, rather than calling * type->constructor/destructor() directly. */ |
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struct dm_dirty_log *dm_dirty_log_create(const char *type_name, |
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struct dm_target *ti, int (*flush_callback_fn)(struct dm_target *ti), unsigned argc, char **argv); |
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void dm_dirty_log_destroy(struct dm_dirty_log *log); |
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#endif /* __KERNEL__ */ #endif /* _LINUX_DM_DIRTY_LOG_H */ |