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/*
* Copyright (C) 2001 Sistina Software (UK) Limited.
* Copyright (C) 2004-2008 Red Hat, Inc. All rights reserved.
*
* This file is released under the LGPL.
*/
#ifndef _LINUX_DEVICE_MAPPER_H
#define _LINUX_DEVICE_MAPPER_H
#include <linux/bio.h>
#include <linux/blkdev.h>
struct dm_dev;
struct dm_target;
struct dm_table;
struct mapped_device;
struct bio_vec;
typedef enum { STATUSTYPE_INFO, STATUSTYPE_TABLE } status_type_t;
union map_info {
void *ptr;
unsigned long long ll;
unsigned target_request_nr;
};
/*
* 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
* = 1: simple remap complete
* = 2: The target wants to push back the io
*/
typedef int (*dm_map_fn) (struct dm_target *ti, struct bio *bio,
union map_info *map_context);
typedef int (*dm_map_request_fn) (struct dm_target *ti, struct request *clone,
union map_info *map_context);
/*
* 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).
* 2 : The target wants to push back the io
*/
typedef int (*dm_endio_fn) (struct dm_target *ti,
struct bio *bio, int error,
union map_info *map_context);
typedef int (*dm_request_endio_fn) (struct dm_target *ti,
struct request *clone, int error,
union map_info *map_context);
typedef void (*dm_flush_fn) (struct dm_target *ti);
typedef void (*dm_presuspend_fn) (struct dm_target *ti);
typedef void (*dm_postsuspend_fn) (struct dm_target *ti);
typedef int (*dm_preresume_fn) (struct dm_target *ti);
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);
typedef int (*dm_ioctl_fn) (struct dm_target *ti, unsigned int cmd,
unsigned long arg);
typedef int (*dm_merge_fn) (struct dm_target *ti, struct bvec_merge_data *bvm,
struct bio_vec *biovec, int max_size);
typedef int (*iterate_devices_callout_fn) (struct dm_target *ti,
struct dm_dev *dev,
sector_t start, sector_t len,
void *data);
typedef int (*dm_iterate_devices_fn) (struct dm_target *ti,
iterate_devices_callout_fn fn,
void *data);
typedef void (*dm_io_hints_fn) (struct dm_target *ti,
struct queue_limits *limits);
/*
* 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);
void dm_error(const char *message);
/*
* Combine device limits.
*/
int dm_set_device_limits(struct dm_target *ti, struct dm_dev *dev,
sector_t start, sector_t len, void *data);
struct dm_dev {
struct block_device *bdev;
fmode_t mode;
char name[16];
};
/*
* Constructors should call these functions to ensure destination devices
* are opened/closed correctly.
*/
int dm_get_device(struct dm_target *ti, const char *path, fmode_t mode,
struct dm_dev **result);
void dm_put_device(struct dm_target *ti, struct dm_dev *d);
/*
* Information about a target type
*/
/*
* Target features
*/
struct target_type {
uint64_t features;
const char *name;
struct module *module;
unsigned version[3];
dm_ctr_fn ctr;
dm_dtr_fn dtr;
dm_map_fn map;
dm_map_request_fn map_rq;
dm_endio_fn end_io;
dm_request_endio_fn rq_end_io;
dm_flush_fn flush;
dm_presuspend_fn presuspend;
dm_postsuspend_fn postsuspend;
dm_preresume_fn preresume;
dm_resume_fn resume;
dm_status_fn status;
dm_message_fn message;
dm_ioctl_fn ioctl;
dm_merge_fn merge;
dm_busy_fn busy;
dm_iterate_devices_fn iterate_devices;
dm_io_hints_fn io_hints;
/* For internal device-mapper use. */
struct list_head list;
};
struct dm_target {
struct dm_table *table;
struct target_type *type;
/* target limits */
sector_t begin;
sector_t len;
/* Always a power of 2 */
sector_t split_io;
/*
* A number of zero-length barrier requests that will be submitted
* to the target for the purpose of flushing cache.
*
* The request number will be placed in union map_info->target_request_nr.
* It is a responsibility of the target driver to remap these requests
* to the real underlying devices.
*/
unsigned num_flush_requests;
/*
* 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;
/* target specific data */
void *private;
/* Used to provide an error string from the ctr */
char *error;
/*
* Set if this target needs to receive discards regardless of
* whether or not its underlying devices have support.
*/
unsigned discards_supported:1;
};
/* Each target can link one of these into the table */
struct dm_target_callbacks {
struct list_head list;
int (*congested_fn) (struct dm_target_callbacks *, int);
};
int dm_register_target(struct target_type *t);
void dm_unregister_target(struct target_type *t);
/*-----------------------------------------------------------------
* 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.
*/
int dm_suspend(struct mapped_device *md, unsigned suspend_flags);
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);
uint32_t dm_next_uevent_seq(struct mapped_device *md);
void dm_uevent_add(struct mapped_device *md, struct list_head *elist);
/*
* Info functions.
*/
const char *dm_device_name(struct mapped_device *md);
int dm_copy_name_and_uuid(struct mapped_device *md, char *name, char *uuid);
struct gendisk *dm_disk(struct mapped_device *md);
int dm_suspended(struct dm_target *ti);
int dm_noflush_suspending(struct dm_target *ti);
union map_info *dm_get_mapinfo(struct bio *bio);
union map_info *dm_get_rq_mapinfo(struct request *rq);
/*
* 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.
*/
int dm_table_create(struct dm_table **result, fmode_t mode,
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);
/*
* Target_ctr should call this if it needs to add any callbacks.
*/
void dm_table_add_target_callbacks(struct dm_table *t, struct dm_target_callbacks *cb);
/*
* Finally call this to make the table ready for use.
*/
int dm_table_complete(struct dm_table *t);
/*
* Table reference counting.
*/
struct dm_table *dm_get_live_table(struct mapped_device *md);
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);
fmode_t dm_table_get_mode(struct dm_table *t);
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.
* Returns the previous table, which the caller must destroy.
*/
struct dm_table *dm_swap_table(struct mapped_device *md,
struct dm_table *t);
/*
* A wrapper around vmalloc.
*/
void *dm_vcalloc(unsigned long nmemb, unsigned long elem_size);
/*-----------------------------------------------------------------
* Macros.
*---------------------------------------------------------------*/
#define DM_NAME "device-mapper"
#define DMCRIT(f, arg...) \
printk(KERN_CRIT DM_NAME ": " DM_MSG_PREFIX ": " f "\n", ## arg)
#define DMERR(f, arg...) \
printk(KERN_ERR DM_NAME ": " DM_MSG_PREFIX ": " f "\n", ## arg)
#define DMERR_LIMIT(f, arg...) \
do { \
if (printk_ratelimit()) \
printk(KERN_ERR DM_NAME ": " DM_MSG_PREFIX ": " \
f "\n", ## arg); \
} while (0)
#define DMWARN(f, arg...) \
printk(KERN_WARNING DM_NAME ": " DM_MSG_PREFIX ": " f "\n", ## arg)
#define DMWARN_LIMIT(f, arg...) \
do { \
if (printk_ratelimit()) \
printk(KERN_WARNING DM_NAME ": " DM_MSG_PREFIX ": " \
f "\n", ## arg); \
} while (0)
#define DMINFO(f, arg...) \
printk(KERN_INFO DM_NAME ": " DM_MSG_PREFIX ": " f "\n", ## arg)
#define DMINFO_LIMIT(f, arg...) \
do { \
if (printk_ratelimit()) \
printk(KERN_INFO DM_NAME ": " DM_MSG_PREFIX ": " f \
"\n", ## arg); \
} while (0)
#ifdef CONFIG_DM_DEBUG
# define DMDEBUG(f, arg...) \
printk(KERN_DEBUG DM_NAME ": " DM_MSG_PREFIX " DEBUG: " f "\n", ## arg)
# define DMDEBUG_LIMIT(f, arg...) \
do { \
if (printk_ratelimit()) \
printk(KERN_DEBUG DM_NAME ": " DM_MSG_PREFIX ": " f \
"\n", ## 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))
#define dm_array_too_big(fixed, obj, num) \
((num) > (UINT_MAX - (fixed)) / (obj))
/*
* 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)
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);
}
/*-----------------------------------------------------------------
* 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);
#endif /* _LINUX_DEVICE_MAPPER_H */
