/*
* 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>
#include <linux/math64.h>
#include <linux/ratelimit.h>
struct dm_dev;
struct dm_target;
struct dm_table;
struct mapped_device;
struct bio_vec;
/*
* Type of table, mapped_device's mempool and request_queue
*/
enum dm_queue_mode {
DM_TYPE_NONE = 0,
DM_TYPE_BIO_BASED = 1,
DM_TYPE_REQUEST_BASED = 2,
DM_TYPE_MQ_REQUEST_BASED = 3,
DM_TYPE_DAX_BIO_BASED = 4,
};
typedef enum { STATUSTYPE_INFO, STATUSTYPE_TABLE } status_type_t;
union map_info {
void *ptr;
};
/*
* 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);
typedef int (*dm_clone_and_map_request_fn) (struct dm_target *ti,
struct request *rq,
union map_info *map_context,
struct request **clone);
typedef void (*dm_release_clone_request_fn) (struct request *clone);
/*
* 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, blk_status_t *error);
typedef int (*dm_request_endio_fn) (struct dm_target *ti,
struct request *clone, blk_status_t error,
union map_info *map_context);
typedef void (*dm_presuspend_fn) (struct dm_target *ti);
typedef void (*dm_presuspend_undo_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 void (*dm_status_fn) (struct dm_target *ti, status_type_t status_type,
unsigned status_flags, char *result, unsigned maxlen);
typedef int (*dm_message_fn) (struct dm_target *ti, unsigned argc, char **argv);
typedef int (*dm_prepare_ioctl_fn) (struct dm_target *ti,
struct block_device **bdev, fmode_t *mode);
/*
* These iteration functions are typically used to check (and combine)
* properties of underlying devices.
* E.g. Does at least one underlying device support flush?
* Does any underlying device not support WRITE_SAME?
*
* The callout function is called once for each contiguous section of
* an underlying device. State can be maintained in *data.
* Return non-zero to stop iterating through any further devices.
*/
typedef int (*iterate_devices_callout_fn) (struct dm_target *ti,
struct dm_dev *dev,
sector_t start, sector_t len,
void *data);
/*
* This function must iterate through each section of device used by the
* target until it encounters a non-zero return code, which it then returns.
* Returns zero if no callout returned non-zero.
*/
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);
/*
* Returns:
* < 0 : error
* >= 0 : the number of bytes accessible at the address
*/
typedef long (*dm_dax_direct_access_fn) (struct dm_target *ti, pgoff_t pgoff,
long nr_pages, void **kaddr, pfn_t *pfn);
typedef size_t (*dm_dax_copy_from_iter_fn)(struct dm_target *ti, pgoff_t pgoff,
void *addr, size_t bytes, struct iov_iter *i);
#define PAGE_SECTORS (PAGE_SIZE / 512)
void dm_error(const char *message);
struct dm_dev {
struct block_device *bdev;
struct dax_device *dax_dev;
fmode_t mode;
char name[16];
};
dev_t dm_get_dev_t(const char *path);
/*
* 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
*/
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_clone_and_map_request_fn clone_and_map_rq;
dm_release_clone_request_fn release_clone_rq;
dm_endio_fn end_io;
dm_request_endio_fn rq_end_io;
dm_presuspend_fn presuspend;
dm_presuspend_undo_fn presuspend_undo;
dm_postsuspend_fn postsuspend;
dm_preresume_fn preresume;
dm_resume_fn resume;
dm_status_fn status;
dm_message_fn message;
dm_prepare_ioctl_fn prepare_ioctl;
dm_busy_fn busy;
dm_iterate_devices_fn iterate_devices;
dm_io_hints_fn io_hints;
dm_dax_direct_access_fn direct_access;
dm_dax_copy_from_iter_fn dax_copy_from_iter;
/* For internal device-mapper use. */
struct list_head list;
};
/*
* Target features
*/
/*
* Any table that contains an instance of this target must have only one.
*/
#define DM_TARGET_SINGLETON 0x00000001
#define dm_target_needs_singleton(type) ((type)->features & DM_TARGET_SINGLETON)
/*
* Indicates that a target does not support read-only devices.
*/
#define DM_TARGET_ALWAYS_WRITEABLE 0x00000002
#define dm_target_always_writeable(type) \
((type)->features & DM_TARGET_ALWAYS_WRITEABLE)
/*
* Any device that contains a table with an instance of this target may never
* have tables containing any different target type.
*/
#define DM_TARGET_IMMUTABLE 0x00000004
#define dm_target_is_immutable(type) ((type)->features & DM_TARGET_IMMUTABLE)
/*
* Indicates that a target may replace any target; even immutable targets.
* .map, .map_rq, .clone_and_map_rq and .release_clone_rq are all defined.
*/
#define DM_TARGET_WILDCARD 0x00000008
#define dm_target_is_wildcard(type) ((type)->features & DM_TARGET_WILDCARD)
/*
* Some targets need to be sent the same WRITE bio severals times so
* that they can send copies of it to different devices. This function
* examines any supplied bio and returns the number of copies of it the
* target requires.
*/
typedef unsigned (*dm_num_write_bios_fn) (struct dm_target *ti, struct bio *bio);
/*
* A target implements own bio data integrity.
*/
#define DM_TARGET_INTEGRITY 0x00000010
#define dm_target_has_integrity(type) ((type)->features & DM_TARGET_INTEGRITY)
/*
* A target passes integrity data to the lower device.
*/
#define DM_TARGET_PASSES_INTEGRITY 0x00000020
#define dm_target_passes_integrity(type) ((type)->features & DM_TARGET_PASSES_INTEGRITY)
/*
* Indicates that a target supports host-managed zoned block devices.
*/
#define DM_TARGET_ZONED_HM 0x00000040
#define dm_target_supports_zoned_hm(type) ((type)->features & DM_TARGET_ZONED_HM)
struct dm_target {
struct dm_table *table;
struct target_type *type;
/* target limits */
sector_t begin;
sector_t len;
/* If non-zero, maximum size of I/O submitted to a target. */
uint32_t max_io_len;
/*
* A number of zero-length barrier bios that will be submitted
* to the target for the purpose of flushing cache.
*
* The bio number can be accessed with dm_bio_get_target_bio_nr.
* It is a responsibility of the target driver to remap these bios
* to the real underlying devices.
*/
unsigned num_flush_bios;
/*
* The number of discard bios that will be submitted to the target.
* The bio number can be accessed with dm_bio_get_target_bio_nr.
*/
unsigned num_discard_bios;
/*
* The number of WRITE SAME bios that will be submitted to the target.
* The bio number can be accessed with dm_bio_get_target_bio_nr.
*/
unsigned num_write_same_bios;
/*
* The number of WRITE ZEROES bios that will be submitted to the target.
* The bio number can be accessed with dm_bio_get_target_bio_nr.
*/
unsigned num_write_zeroes_bios;
/*
* The minimum number of extra bytes allocated in each io for the
* target to use.
*/
unsigned per_io_data_size;
/*
* If defined, this function is called to find out how many
* duplicate bios should be sent to the target when writing
* data.
*/
dm_num_write_bios_fn num_write_bios;
/* target specific data */
void *private;
/* Used to provide an error string from the ctr */
char *error;
/*
* Set if this target needs to receive flushes regardless of
* whether or not its underlying devices have support.
*/
bool flush_supported:1;
/*
* Set if this target needs to receive discards regardless of
* whether or not its underlying devices have support.
*/
bool discards_supported:1;
/*
* Set if the target required discard bios to be split
* on max_io_len boundary.
*/
bool split_discard_bios: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);
};
/*
* For bio-based dm.
* One of these is allocated for each bio.
* This structure shouldn't be touched directly by target drivers.
* It is here so that we can inline dm_per_bio_data and
* dm_bio_from_per_bio_data
*/
struct dm_target_io {
struct dm_io *io;
struct dm_target *ti;
unsigned target_bio_nr;
unsigned *len_ptr;
struct bio clone;
};
static inline void *dm_per_bio_data(struct bio *bio, size_t data_size)
{
return (char *)bio - offsetof(struct dm_target_io, clone) - data_size;
}
static inline struct bio *dm_bio_from_per_bio_data(void *data, size_t data_size)
{
return (struct bio *)((char *)data + data_size + offsetof(struct dm_target_io, clone));
}
static inline unsigned dm_bio_get_target_bio_nr(const struct bio *bio)
{
return container_of(bio, struct dm_target_io, clone)->target_bio_nr;
}
int dm_register_target(struct target_type *t);
void dm_unregister_target(struct target_type *t);
/*
* Target argument parsing.
*/
struct dm_arg_set {
unsigned argc;
char **argv;
};
/*
* The minimum and maximum value of a numeric argument, together with
* the error message to use if the number is found to be outside that range.
*/
struct dm_arg {
unsigned min;
unsigned max;
char *error;
};
/*
* Validate the next argument, either returning it as *value or, if invalid,
* returning -EINVAL and setting *error.
*/
int dm_read_arg(const struct dm_arg *arg, struct dm_arg_set *arg_set,
unsigned *value, char **error);
/*
* Process the next argument as the start of a group containing between
* arg->min and arg->max further arguments. Either return the size as
* *num_args or, if invalid, return -EINVAL and set *error.
*/
int dm_read_arg_group(const struct dm_arg *arg, struct dm_arg_set *arg_set,
unsigned *num_args, char **error);
/*
* Return the current argument and shift to the next.
*/
const char *dm_shift_arg(struct dm_arg_set *as);
/*
* Move through num_args arguments.
*/
void dm_consume_args(struct dm_arg_set *as, unsigned num_args);
/*-----------------------------------------------------------------
* 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);
int dm_hold(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);
void dm_accept_partial_bio(struct bio *bio, unsigned n_sectors);
void dm_remap_zone_report(struct dm_target *ti, struct bio *bio,
sector_t start);
union map_info *dm_get_rq_mapinfo(struct request *rq);
struct queue_limits *dm_get_queue_limits(struct mapped_device *md);
/*
* 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);
/*
* Target can use this to set the table's type.
* Can only ever be called from a target's ctr.
* Useful for "hybrid" target (supports both bio-based
* and request-based).
*/
void dm_table_set_type(struct dm_table *t, enum dm_queue_mode type);
/*
* Finally call this to make the table ready for use.
*/
int dm_table_complete(struct dm_table *t);
/*
* Target may require that it is never sent I/O larger than len.
*/
int __must_check dm_set_target_max_io_len(struct dm_target *ti, sector_t len);
/*
* Table reference counting.
*/
struct dm_table *dm_get_live_table(struct mapped_device *md, int *srcu_idx);
void dm_put_live_table(struct mapped_device *md, int srcu_idx);
void dm_sync_table(struct mapped_device *md);
/*
* 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);
/*
* Run the queue for request-based targets.
*/
void dm_table_run_md_queue_async(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 DM_RATELIMIT(pr_func, fmt, ...) \
do { \
static DEFINE_RATELIMIT_STATE(rs, DEFAULT_RATELIMIT_INTERVAL, \
DEFAULT_RATELIMIT_BURST); \
\
if (__ratelimit(&rs)) \
pr_func(DM_FMT(fmt), ##__VA_ARGS__); \
} while (0)
#define DM_FMT(fmt) DM_NAME ": " DM_MSG_PREFIX ": " fmt "\n"
#define DMCRIT(fmt, ...) pr_crit(DM_FMT(fmt), ##__VA_ARGS__)
#define DMERR(fmt, ...) pr_err(DM_FMT(fmt), ##__VA_ARGS__)
#define DMERR_LIMIT(fmt, ...) DM_RATELIMIT(pr_err, fmt, ##__VA_ARGS__)
#define DMWARN(fmt, ...) pr_warn(DM_FMT(fmt), ##__VA_ARGS__)
#define DMWARN_LIMIT(fmt, ...) DM_RATELIMIT(pr_warn, fmt, ##__VA_ARGS__)
#define DMINFO(fmt, ...) pr_info(DM_FMT(fmt), ##__VA_ARGS__)
#define DMINFO_LIMIT(fmt, ...) DM_RATELIMIT(pr_info, fmt, ##__VA_ARGS__)
#ifdef CONFIG_DM_DEBUG
#define DMDEBUG(fmt, ...) printk(KERN_DEBUG DM_FMT(fmt), ##__VA_ARGS__)
#define DMDEBUG_LIMIT(fmt, ...) DM_RATELIMIT(pr_debug, fmt, ##__VA_ARGS__)
#else
#define DMDEBUG(fmt, ...) no_printk(fmt, ##__VA_ARGS__)
#define DMDEBUG_LIMIT(fmt, ...) no_printk(fmt, ##__VA_ARGS__)
#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_DONE 0
#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
#define DM_MAPIO_DELAY_REQUEUE 3
#define DM_MAPIO_KILL 4
#define dm_sector_div64(x, y)( \
{ \
u64 _res; \
(x) = div64_u64_rem(x, y, &_res); \
_res; \
} \
)
/*
* 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);
}
#endif /* _LINUX_DEVICE_MAPPER_H */
