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Release 4.12 include/linux/device-mapper.h

Directory: include/linux
 * Copyright (C) 2001 Sistina Software (UK) Limited.
 * Copyright (C) 2004-2008 Red Hat, Inc. All rights reserved.
 * This file is released under the LGPL.



#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 {

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, int error);

typedef int (*dm_request_endio_fn) (struct dm_target *ti,
				    struct request *clone, int 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);

#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;

	/* 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(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(type) ((type)->features & DM_TARGET_PASSES_INTEGRITY)

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; }


Mikulas Patocka33100.00%1100.00%

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)); }


Mikulas Patocka40100.00%1100.00%

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; }


Mikulas Patocka2492.31%150.00%
Alasdair G. Kergon27.69%150.00%

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(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(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); 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" #ifdef CONFIG_PRINTK extern struct ratelimit_state dm_ratelimit_state; #define dm_ratelimit() __ratelimit(&dm_ratelimit_state) #else #define dm_ratelimit() 0 #endif #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 (dm_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 (dm_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 (dm_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 (dm_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_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); }


Alasdair G. Kergon18100.00%1100.00%

static inline unsigned long to_bytes(sector_t n) { return (n << SECTOR_SHIFT); }


Alasdair G. Kergon18100.00%1100.00%


Overall Contributors

Alasdair G. Kergon65534.91%1518.75%
Mike Snitzer33417.80%1721.25%
Mikulas Patocka24813.22%1518.75%
Alan Cox22111.78%11.25%
Kiyoshi Ueda754.00%56.25%
Milan Broz492.61%45.00%
Mike Anderson402.13%22.50%
Andrew Morton392.08%22.50%
Neil Brown382.03%11.25%
Joe Thornber371.97%33.75%
Namhyung Kim291.55%11.25%
Toshi Kani261.39%11.25%
Christoph Hellwig231.23%45.00%
Bart Van Assche211.12%11.25%
Dan J Williams160.85%22.50%
Cheng Renquan50.27%11.25%
Al Viro40.21%11.25%
Andi Kleen30.16%11.25%
Heinz Mauelshagen30.16%11.25%
Nikanth Karthikesan10.05%11.25%
Directory: include/linux
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