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include/linux/device-mapper.h
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/* * Copyright (C) 2001 Sistina Software (UK) Limited. |
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* Copyright (C) 2004-2008 Red Hat, Inc. All rights reserved. |
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* * This file is released under the LGPL. */ #ifndef _LINUX_DEVICE_MAPPER_H #define _LINUX_DEVICE_MAPPER_H |
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#include <linux/bio.h> |
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#include <linux/blkdev.h> |
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struct dm_dev; |
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struct dm_target; struct dm_table; |
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struct mapped_device; |
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struct bio_vec; |
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typedef enum { STATUSTYPE_INFO, STATUSTYPE_TABLE } status_type_t; union map_info { void *ptr; unsigned long long ll; |
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unsigned target_request_nr; |
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}; /* * In the constructor the target parameter will already have the * table, type, begin and len fields filled in. */ typedef int (*dm_ctr_fn) (struct dm_target *target, unsigned int argc, char **argv); /* * The destructor doesn't need to free the dm_target, just * anything hidden ti->private. */ typedef void (*dm_dtr_fn) (struct dm_target *ti); /* * The map function must return: * < 0: error * = 0: The target will handle the io by resubmitting it later |
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* = 1: simple remap complete |
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* = 2: The target wants to push back the io |
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*/ typedef int (*dm_map_fn) (struct dm_target *ti, struct bio *bio, union map_info *map_context); |
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typedef int (*dm_map_request_fn) (struct dm_target *ti, struct request *clone, union map_info *map_context); |
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/* * Returns: * < 0 : error (currently ignored) * 0 : ended successfully * 1 : for some reason the io has still not completed (eg, * multipath target might want to requeue a failed io). |
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* 2 : The target wants to push back the io |
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*/ typedef int (*dm_endio_fn) (struct dm_target *ti, struct bio *bio, int error, union map_info *map_context); |
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typedef int (*dm_request_endio_fn) (struct dm_target *ti, struct request *clone, int error, union map_info *map_context); |
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typedef void (*dm_flush_fn) (struct dm_target *ti); |
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typedef void (*dm_presuspend_fn) (struct dm_target *ti); typedef void (*dm_postsuspend_fn) (struct dm_target *ti); |
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typedef int (*dm_preresume_fn) (struct dm_target *ti); |
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typedef void (*dm_resume_fn) (struct dm_target *ti); typedef int (*dm_status_fn) (struct dm_target *ti, status_type_t status_type, char *result, unsigned int maxlen); typedef int (*dm_message_fn) (struct dm_target *ti, unsigned argc, char **argv); |
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typedef int (*dm_ioctl_fn) (struct dm_target *ti, unsigned int cmd, |
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unsigned long arg); |
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typedef int (*dm_merge_fn) (struct dm_target *ti, struct bvec_merge_data *bvm, struct bio_vec *biovec, int max_size); |
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typedef int (*iterate_devices_callout_fn) (struct dm_target *ti, struct dm_dev *dev, |
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sector_t start, sector_t len, |
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void *data); typedef int (*dm_iterate_devices_fn) (struct dm_target *ti, iterate_devices_callout_fn fn, void *data); |
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typedef void (*dm_io_hints_fn) (struct dm_target *ti, struct queue_limits *limits); |
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/* * Returns: * 0: The target can handle the next I/O immediately. * 1: The target can't handle the next I/O immediately. */ typedef int (*dm_busy_fn) (struct dm_target *ti); |
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void dm_error(const char *message); /* |
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* Combine device limits. */ |
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int dm_set_device_limits(struct dm_target *ti, struct dm_dev *dev, |
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sector_t start, sector_t len, void *data); |
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struct dm_dev { struct block_device *bdev; |
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fmode_t mode; |
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char name[16]; }; |
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/* |
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* Constructors should call these functions to ensure destination devices * are opened/closed correctly. |
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*/ |
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int dm_get_device(struct dm_target *ti, const char *path, fmode_t mode, struct dm_dev **result); |
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void dm_put_device(struct dm_target *ti, struct dm_dev *d); /* * Information about a target type */ |
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/* * Target features */ |
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struct target_type { |
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uint64_t features; |
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const char *name; struct module *module; |
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unsigned version[3]; |
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dm_ctr_fn ctr; dm_dtr_fn dtr; dm_map_fn map; |
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dm_map_request_fn map_rq; |
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dm_endio_fn end_io; |
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dm_request_endio_fn rq_end_io; |
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dm_flush_fn flush; |
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dm_presuspend_fn presuspend; dm_postsuspend_fn postsuspend; |
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dm_preresume_fn preresume; |
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dm_resume_fn resume; dm_status_fn status; dm_message_fn message; |
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dm_ioctl_fn ioctl; |
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dm_merge_fn merge; |
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dm_busy_fn busy; |
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dm_iterate_devices_fn iterate_devices; |
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dm_io_hints_fn io_hints; |
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/* For internal device-mapper use. */ struct list_head list; |
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}; |
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struct dm_target { struct dm_table *table; struct target_type *type; /* target limits */ sector_t begin; sector_t len; |
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/* Always a power of 2 */ sector_t split_io; /* |
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* A number of zero-length barrier requests that will be submitted * to the target for the purpose of flushing cache. * |
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* The request number will be placed in union map_info->target_request_nr. |
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* It is a responsibility of the target driver to remap these requests * to the real underlying devices. */ unsigned num_flush_requests; |
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/* * The number of discard requests that will be submitted to the * target. map_info->request_nr is used just like num_flush_requests. */ unsigned num_discard_requests; |
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/* target specific data */ void *private; /* Used to provide an error string from the ctr */ char *error; }; int dm_register_target(struct target_type *t); |
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void dm_unregister_target(struct target_type *t); |
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/*----------------------------------------------------------------- * Functions for creating and manipulating mapped devices. * Drop the reference with dm_put when you finish with the object. *---------------------------------------------------------------*/ /* * DM_ANY_MINOR chooses the next available minor number. */ #define DM_ANY_MINOR (-1) int dm_create(int minor, struct mapped_device **md); /* * Reference counting for md. */ struct mapped_device *dm_get_md(dev_t dev); void dm_get(struct mapped_device *md); void dm_put(struct mapped_device *md); /* * An arbitrary pointer may be stored alongside a mapped device. */ void dm_set_mdptr(struct mapped_device *md, void *ptr); void *dm_get_mdptr(struct mapped_device *md); /* * A device can still be used while suspended, but I/O is deferred. */ |
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int dm_suspend(struct mapped_device *md, unsigned suspend_flags); |
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int dm_resume(struct mapped_device *md); /* * Event functions. */ uint32_t dm_get_event_nr(struct mapped_device *md); int dm_wait_event(struct mapped_device *md, int event_nr); |
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uint32_t dm_next_uevent_seq(struct mapped_device *md); void dm_uevent_add(struct mapped_device *md, struct list_head *elist); |
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/* * Info functions. */ |
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const char *dm_device_name(struct mapped_device *md); |
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int dm_copy_name_and_uuid(struct mapped_device *md, char *name, char *uuid); |
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struct gendisk *dm_disk(struct mapped_device *md); |
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int dm_suspended(struct dm_target *ti); |
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int dm_noflush_suspending(struct dm_target *ti); |
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union map_info *dm_get_mapinfo(struct bio *bio); |
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union map_info *dm_get_rq_mapinfo(struct request *rq); |
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/* * Geometry functions. */ int dm_get_geometry(struct mapped_device *md, struct hd_geometry *geo); int dm_set_geometry(struct mapped_device *md, struct hd_geometry *geo); /*----------------------------------------------------------------- * Functions for manipulating device-mapper tables. *---------------------------------------------------------------*/ /* * First create an empty table. */ |
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int dm_table_create(struct dm_table **result, fmode_t mode, |
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unsigned num_targets, struct mapped_device *md); /* * Then call this once for each target. */ int dm_table_add_target(struct dm_table *t, const char *type, sector_t start, sector_t len, char *params); /* * Finally call this to make the table ready for use. */ int dm_table_complete(struct dm_table *t); /* |
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* Unplug all devices in a table. */ void dm_table_unplug_all(struct dm_table *t); /* |
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* Table reference counting. */ |
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struct dm_table *dm_get_live_table(struct mapped_device *md); |
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void dm_table_get(struct dm_table *t); void dm_table_put(struct dm_table *t); /* * Queries */ sector_t dm_table_get_size(struct dm_table *t); unsigned int dm_table_get_num_targets(struct dm_table *t); |
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fmode_t dm_table_get_mode(struct dm_table *t); |
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struct mapped_device *dm_table_get_md(struct dm_table *t); /* * Trigger an event. */ void dm_table_event(struct dm_table *t); /* * The device must be suspended before calling this method. |
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* Returns the previous table, which the caller must destroy. |
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*/ |
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struct dm_table *dm_swap_table(struct mapped_device *md, struct dm_table *t); |
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/* * A wrapper around vmalloc. */ void *dm_vcalloc(unsigned long nmemb, unsigned long elem_size); |
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/*----------------------------------------------------------------- * Macros. *---------------------------------------------------------------*/ #define DM_NAME "device-mapper" |
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#define DMCRIT(f, arg...) \ printk(KERN_CRIT DM_NAME ": " DM_MSG_PREFIX ": " f " ", ## arg) |
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#define DMERR(f, arg...) \ printk(KERN_ERR DM_NAME ": " DM_MSG_PREFIX ": " f " ", ## arg) #define DMERR_LIMIT(f, arg...) \ do { \ if (printk_ratelimit()) \ printk(KERN_ERR DM_NAME ": " DM_MSG_PREFIX ": " \ f " ", ## arg); \ } while (0) #define DMWARN(f, arg...) \ printk(KERN_WARNING DM_NAME ": " DM_MSG_PREFIX ": " f " ", ## arg) #define DMWARN_LIMIT(f, arg...) \ do { \ if (printk_ratelimit()) \ printk(KERN_WARNING DM_NAME ": " DM_MSG_PREFIX ": " \ f " ", ## arg); \ } while (0) #define DMINFO(f, arg...) \ printk(KERN_INFO DM_NAME ": " DM_MSG_PREFIX ": " f " ", ## arg) #define DMINFO_LIMIT(f, arg...) \ do { \ if (printk_ratelimit()) \ printk(KERN_INFO DM_NAME ": " DM_MSG_PREFIX ": " f \ " ", ## arg); \ } while (0) #ifdef CONFIG_DM_DEBUG # define DMDEBUG(f, arg...) \ printk(KERN_DEBUG DM_NAME ": " DM_MSG_PREFIX " DEBUG: " f " ", ## arg) # define DMDEBUG_LIMIT(f, arg...) \ do { \ if (printk_ratelimit()) \ printk(KERN_DEBUG DM_NAME ": " DM_MSG_PREFIX ": " f \ " ", ## arg); \ } while (0) #else # define DMDEBUG(f, arg...) do {} while (0) # define DMDEBUG_LIMIT(f, arg...) do {} while (0) #endif #define DMEMIT(x...) sz += ((sz >= maxlen) ? \ 0 : scnprintf(result + sz, maxlen - sz, x)) #define SECTOR_SHIFT 9 /* * Definitions of return values from target end_io function. */ #define DM_ENDIO_INCOMPLETE 1 #define DM_ENDIO_REQUEUE 2 /* * Definitions of return values from target map function. */ #define DM_MAPIO_SUBMITTED 0 #define DM_MAPIO_REMAPPED 1 #define DM_MAPIO_REQUEUE DM_ENDIO_REQUEUE /* * Ceiling(n / sz) */ #define dm_div_up(n, sz) (((n) + (sz) - 1) / (sz)) #define dm_sector_div_up(n, sz) ( \ { \ sector_t _r = ((n) + (sz) - 1); \ sector_div(_r, (sz)); \ _r; \ } \ ) /* * ceiling(n / size) * size */ #define dm_round_up(n, sz) (dm_div_up((n), (sz)) * (sz)) |
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#define dm_array_too_big(fixed, obj, num) \ ((num) > (UINT_MAX - (fixed)) / (obj)) |
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/* * Sector offset taken relative to the start of the target instead of * relative to the start of the device. */ #define dm_target_offset(ti, sector) ((sector) - (ti)->begin) |
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static inline sector_t to_sector(unsigned long n) { return (n >> SECTOR_SHIFT); } static inline unsigned long to_bytes(sector_t n) { return (n << SECTOR_SHIFT); } |
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/*----------------------------------------------------------------- * Helper for block layer and dm core operations *---------------------------------------------------------------*/ void dm_dispatch_request(struct request *rq); void dm_requeue_unmapped_request(struct request *rq); void dm_kill_unmapped_request(struct request *rq, int error); int dm_underlying_device_busy(struct request_queue *q); |
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#endif /* _LINUX_DEVICE_MAPPER_H */ |