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author | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 15:20:36 -0700 |
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committer | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 15:20:36 -0700 |
commit | 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch) | |
tree | 0bba044c4ce775e45a88a51686b5d9f90697ea9d /drivers/md/dm-log.h | |
download | lwn-1da177e4c3f41524e886b7f1b8a0c1fc7321cac2.tar.gz lwn-1da177e4c3f41524e886b7f1b8a0c1fc7321cac2.zip |
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
Diffstat (limited to 'drivers/md/dm-log.h')
-rw-r--r-- | drivers/md/dm-log.h | 130 |
1 files changed, 130 insertions, 0 deletions
diff --git a/drivers/md/dm-log.h b/drivers/md/dm-log.h new file mode 100644 index 000000000000..5ae5309ebf28 --- /dev/null +++ b/drivers/md/dm-log.h @@ -0,0 +1,130 @@ +/* + * Copyright (C) 2003 Sistina Software + * + * This file is released under the LGPL. + */ + +#ifndef DM_DIRTY_LOG +#define DM_DIRTY_LOG + +#include "dm.h" + +typedef sector_t region_t; + +struct dirty_log_type; + +struct dirty_log { + struct dirty_log_type *type; + void *context; +}; + +struct dirty_log_type { + struct list_head list; + const char *name; + struct module *module; + unsigned int use_count; + + int (*ctr)(struct dirty_log *log, struct dm_target *ti, + unsigned int argc, char **argv); + void (*dtr)(struct dirty_log *log); + + /* + * There are times when we don't want the log to touch + * the disk. + */ + int (*suspend)(struct dirty_log *log); + int (*resume)(struct dirty_log *log); + + /* + * Retrieves the smallest size of region that the log can + * deal with. + */ + uint32_t (*get_region_size)(struct dirty_log *log); + + /* + * A predicate to say whether a region is clean or not. + * May block. + */ + int (*is_clean)(struct 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 dirty_log *log, region_t region, int can_block); + + /* + * Flush the current log state (eg, to disk). This + * function may block. + */ + int (*flush)(struct 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 dirty_log *log, region_t region); + void (*clear_region)(struct 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 dirty_log *log, region_t *region); + + /* + * This notifies the log that the resync of an area has + * been completed. The log should then mark this region + * as CLEAN. + */ + void (*complete_resync_work)(struct dirty_log *log, + region_t region, int success); + + /* + * Returns the number of regions that are in sync. + */ + region_t (*get_sync_count)(struct dirty_log *log); + + /* + * Support function for mirror status requests. + */ + int (*status)(struct dirty_log *log, status_type_t status_type, + char *result, unsigned int maxlen); +}; + +int dm_register_dirty_log_type(struct dirty_log_type *type); +int dm_unregister_dirty_log_type(struct dirty_log_type *type); + + +/* + * Make sure you use these two functions, rather than calling + * type->constructor/destructor() directly. + */ +struct dirty_log *dm_create_dirty_log(const char *type_name, struct dm_target *ti, + unsigned int argc, char **argv); +void dm_destroy_dirty_log(struct dirty_log *log); + +/* + * init/exit functions. + */ +int dm_dirty_log_init(void); +void dm_dirty_log_exit(void); + +#endif |