2 * Copyright (C) 2001 Sistina Software (UK) Limited.
3 * Copyright (C) 2004-2008 Red Hat, Inc. All rights reserved.
5 * This file is released under the LGPL.
8 #ifndef _LINUX_DEVICE_MAPPER_H
9 #define _LINUX_DEVICE_MAPPER_H
11 #include <linux/bio.h>
12 #include <linux/blkdev.h>
13 #include <linux/math64.h>
14 #include <linux/ratelimit.h>
22 typedef enum { STATUSTYPE_INFO
, STATUSTYPE_TABLE
} status_type_t
;
29 * In the constructor the target parameter will already have the
30 * table, type, begin and len fields filled in.
32 typedef int (*dm_ctr_fn
) (struct dm_target
*target
,
33 unsigned int argc
, char **argv
);
36 * The destructor doesn't need to free the dm_target, just
37 * anything hidden ti->private.
39 typedef void (*dm_dtr_fn
) (struct dm_target
*ti
);
42 * The map function must return:
44 * = 0: The target will handle the io by resubmitting it later
45 * = 1: simple remap complete
46 * = 2: The target wants to push back the io
48 typedef int (*dm_map_fn
) (struct dm_target
*ti
, struct bio
*bio
);
49 typedef int (*dm_map_request_fn
) (struct dm_target
*ti
, struct request
*clone
,
50 union map_info
*map_context
);
51 typedef int (*dm_clone_and_map_request_fn
) (struct dm_target
*ti
,
53 union map_info
*map_context
,
54 struct request
**clone
);
55 typedef void (*dm_release_clone_request_fn
) (struct request
*clone
);
59 * < 0 : error (currently ignored)
60 * 0 : ended successfully
61 * 1 : for some reason the io has still not completed (eg,
62 * multipath target might want to requeue a failed io).
63 * 2 : The target wants to push back the io
65 typedef int (*dm_endio_fn
) (struct dm_target
*ti
,
66 struct bio
*bio
, int error
);
67 typedef int (*dm_request_endio_fn
) (struct dm_target
*ti
,
68 struct request
*clone
, int error
,
69 union map_info
*map_context
);
71 typedef void (*dm_presuspend_fn
) (struct dm_target
*ti
);
72 typedef void (*dm_presuspend_undo_fn
) (struct dm_target
*ti
);
73 typedef void (*dm_postsuspend_fn
) (struct dm_target
*ti
);
74 typedef int (*dm_preresume_fn
) (struct dm_target
*ti
);
75 typedef void (*dm_resume_fn
) (struct dm_target
*ti
);
77 typedef void (*dm_status_fn
) (struct dm_target
*ti
, status_type_t status_type
,
78 unsigned status_flags
, char *result
, unsigned maxlen
);
80 typedef int (*dm_message_fn
) (struct dm_target
*ti
, unsigned argc
, char **argv
);
82 typedef int (*dm_prepare_ioctl_fn
) (struct dm_target
*ti
,
83 struct block_device
**bdev
, fmode_t
*mode
);
86 * These iteration functions are typically used to check (and combine)
87 * properties of underlying devices.
88 * E.g. Does at least one underlying device support flush?
89 * Does any underlying device not support WRITE_SAME?
91 * The callout function is called once for each contiguous section of
92 * an underlying device. State can be maintained in *data.
93 * Return non-zero to stop iterating through any further devices.
95 typedef int (*iterate_devices_callout_fn
) (struct dm_target
*ti
,
97 sector_t start
, sector_t len
,
101 * This function must iterate through each section of device used by the
102 * target until it encounters a non-zero return code, which it then returns.
103 * Returns zero if no callout returned non-zero.
105 typedef int (*dm_iterate_devices_fn
) (struct dm_target
*ti
,
106 iterate_devices_callout_fn fn
,
109 typedef void (*dm_io_hints_fn
) (struct dm_target
*ti
,
110 struct queue_limits
*limits
);
114 * 0: The target can handle the next I/O immediately.
115 * 1: The target can't handle the next I/O immediately.
117 typedef int (*dm_busy_fn
) (struct dm_target
*ti
);
119 void dm_error(const char *message
);
122 struct block_device
*bdev
;
128 * Constructors should call these functions to ensure destination devices
129 * are opened/closed correctly.
131 int dm_get_device(struct dm_target
*ti
, const char *path
, fmode_t mode
,
132 struct dm_dev
**result
);
133 void dm_put_device(struct dm_target
*ti
, struct dm_dev
*d
);
136 * Information about a target type
142 struct module
*module
;
147 dm_map_request_fn map_rq
;
148 dm_clone_and_map_request_fn clone_and_map_rq
;
149 dm_release_clone_request_fn release_clone_rq
;
151 dm_request_endio_fn rq_end_io
;
152 dm_presuspend_fn presuspend
;
153 dm_presuspend_undo_fn presuspend_undo
;
154 dm_postsuspend_fn postsuspend
;
155 dm_preresume_fn preresume
;
158 dm_message_fn message
;
159 dm_prepare_ioctl_fn prepare_ioctl
;
161 dm_iterate_devices_fn iterate_devices
;
162 dm_io_hints_fn io_hints
;
164 /* For internal device-mapper use. */
165 struct list_head list
;
173 * Any table that contains an instance of this target must have only one.
175 #define DM_TARGET_SINGLETON 0x00000001
176 #define dm_target_needs_singleton(type) ((type)->features & DM_TARGET_SINGLETON)
179 * Indicates that a target does not support read-only devices.
181 #define DM_TARGET_ALWAYS_WRITEABLE 0x00000002
182 #define dm_target_always_writeable(type) \
183 ((type)->features & DM_TARGET_ALWAYS_WRITEABLE)
186 * Any device that contains a table with an instance of this target may never
187 * have tables containing any different target type.
189 #define DM_TARGET_IMMUTABLE 0x00000004
190 #define dm_target_is_immutable(type) ((type)->features & DM_TARGET_IMMUTABLE)
193 * Some targets need to be sent the same WRITE bio severals times so
194 * that they can send copies of it to different devices. This function
195 * examines any supplied bio and returns the number of copies of it the
198 typedef unsigned (*dm_num_write_bios_fn
) (struct dm_target
*ti
, struct bio
*bio
);
201 struct dm_table
*table
;
202 struct target_type
*type
;
208 /* If non-zero, maximum size of I/O submitted to a target. */
212 * A number of zero-length barrier bios that will be submitted
213 * to the target for the purpose of flushing cache.
215 * The bio number can be accessed with dm_bio_get_target_bio_nr.
216 * It is a responsibility of the target driver to remap these bios
217 * to the real underlying devices.
219 unsigned num_flush_bios
;
222 * The number of discard bios that will be submitted to the target.
223 * The bio number can be accessed with dm_bio_get_target_bio_nr.
225 unsigned num_discard_bios
;
228 * The number of WRITE SAME bios that will be submitted to the target.
229 * The bio number can be accessed with dm_bio_get_target_bio_nr.
231 unsigned num_write_same_bios
;
234 * The minimum number of extra bytes allocated in each bio for the
235 * target to use. dm_per_bio_data returns the data location.
237 unsigned per_bio_data_size
;
240 * If defined, this function is called to find out how many
241 * duplicate bios should be sent to the target when writing
244 dm_num_write_bios_fn num_write_bios
;
246 /* target specific data */
249 /* Used to provide an error string from the ctr */
253 * Set if this target needs to receive flushes regardless of
254 * whether or not its underlying devices have support.
256 bool flush_supported
:1;
259 * Set if this target needs to receive discards regardless of
260 * whether or not its underlying devices have support.
262 bool discards_supported
:1;
265 * Set if the target required discard bios to be split
266 * on max_io_len boundary.
268 bool split_discard_bios
:1;
271 * Set if this target does not return zeroes on discarded blocks.
273 bool discard_zeroes_data_unsupported
:1;
276 /* Each target can link one of these into the table */
277 struct dm_target_callbacks
{
278 struct list_head list
;
279 int (*congested_fn
) (struct dm_target_callbacks
*, int);
284 * One of these is allocated for each bio.
285 * This structure shouldn't be touched directly by target drivers.
286 * It is here so that we can inline dm_per_bio_data and
287 * dm_bio_from_per_bio_data
289 struct dm_target_io
{
291 struct dm_target
*ti
;
292 unsigned target_bio_nr
;
297 static inline void *dm_per_bio_data(struct bio
*bio
, size_t data_size
)
299 return (char *)bio
- offsetof(struct dm_target_io
, clone
) - data_size
;
302 static inline struct bio
*dm_bio_from_per_bio_data(void *data
, size_t data_size
)
304 return (struct bio
*)((char *)data
+ data_size
+ offsetof(struct dm_target_io
, clone
));
307 static inline unsigned dm_bio_get_target_bio_nr(const struct bio
*bio
)
309 return container_of(bio
, struct dm_target_io
, clone
)->target_bio_nr
;
312 int dm_register_target(struct target_type
*t
);
313 void dm_unregister_target(struct target_type
*t
);
316 * Target argument parsing.
324 * The minimum and maximum value of a numeric argument, together with
325 * the error message to use if the number is found to be outside that range.
334 * Validate the next argument, either returning it as *value or, if invalid,
335 * returning -EINVAL and setting *error.
337 int dm_read_arg(struct dm_arg
*arg
, struct dm_arg_set
*arg_set
,
338 unsigned *value
, char **error
);
341 * Process the next argument as the start of a group containing between
342 * arg->min and arg->max further arguments. Either return the size as
343 * *num_args or, if invalid, return -EINVAL and set *error.
345 int dm_read_arg_group(struct dm_arg
*arg
, struct dm_arg_set
*arg_set
,
346 unsigned *num_args
, char **error
);
349 * Return the current argument and shift to the next.
351 const char *dm_shift_arg(struct dm_arg_set
*as
);
354 * Move through num_args arguments.
356 void dm_consume_args(struct dm_arg_set
*as
, unsigned num_args
);
358 /*-----------------------------------------------------------------
359 * Functions for creating and manipulating mapped devices.
360 * Drop the reference with dm_put when you finish with the object.
361 *---------------------------------------------------------------*/
364 * DM_ANY_MINOR chooses the next available minor number.
366 #define DM_ANY_MINOR (-1)
367 int dm_create(int minor
, struct mapped_device
**md
);
370 * Reference counting for md.
372 struct mapped_device
*dm_get_md(dev_t dev
);
373 void dm_get(struct mapped_device
*md
);
374 int dm_hold(struct mapped_device
*md
);
375 void dm_put(struct mapped_device
*md
);
378 * An arbitrary pointer may be stored alongside a mapped device.
380 void dm_set_mdptr(struct mapped_device
*md
, void *ptr
);
381 void *dm_get_mdptr(struct mapped_device
*md
);
384 * A device can still be used while suspended, but I/O is deferred.
386 int dm_suspend(struct mapped_device
*md
, unsigned suspend_flags
);
387 int dm_resume(struct mapped_device
*md
);
392 uint32_t dm_get_event_nr(struct mapped_device
*md
);
393 int dm_wait_event(struct mapped_device
*md
, int event_nr
);
394 uint32_t dm_next_uevent_seq(struct mapped_device
*md
);
395 void dm_uevent_add(struct mapped_device
*md
, struct list_head
*elist
);
400 const char *dm_device_name(struct mapped_device
*md
);
401 int dm_copy_name_and_uuid(struct mapped_device
*md
, char *name
, char *uuid
);
402 struct gendisk
*dm_disk(struct mapped_device
*md
);
403 int dm_suspended(struct dm_target
*ti
);
404 int dm_noflush_suspending(struct dm_target
*ti
);
405 void dm_accept_partial_bio(struct bio
*bio
, unsigned n_sectors
);
406 union map_info
*dm_get_rq_mapinfo(struct request
*rq
);
408 struct queue_limits
*dm_get_queue_limits(struct mapped_device
*md
);
411 * Geometry functions.
413 int dm_get_geometry(struct mapped_device
*md
, struct hd_geometry
*geo
);
414 int dm_set_geometry(struct mapped_device
*md
, struct hd_geometry
*geo
);
416 /*-----------------------------------------------------------------
417 * Functions for manipulating device-mapper tables.
418 *---------------------------------------------------------------*/
421 * First create an empty table.
423 int dm_table_create(struct dm_table
**result
, fmode_t mode
,
424 unsigned num_targets
, struct mapped_device
*md
);
427 * Then call this once for each target.
429 int dm_table_add_target(struct dm_table
*t
, const char *type
,
430 sector_t start
, sector_t len
, char *params
);
433 * Target_ctr should call this if it needs to add any callbacks.
435 void dm_table_add_target_callbacks(struct dm_table
*t
, struct dm_target_callbacks
*cb
);
438 * Finally call this to make the table ready for use.
440 int dm_table_complete(struct dm_table
*t
);
443 * Target may require that it is never sent I/O larger than len.
445 int __must_check
dm_set_target_max_io_len(struct dm_target
*ti
, sector_t len
);
448 * Table reference counting.
450 struct dm_table
*dm_get_live_table(struct mapped_device
*md
, int *srcu_idx
);
451 void dm_put_live_table(struct mapped_device
*md
, int srcu_idx
);
452 void dm_sync_table(struct mapped_device
*md
);
457 sector_t
dm_table_get_size(struct dm_table
*t
);
458 unsigned int dm_table_get_num_targets(struct dm_table
*t
);
459 fmode_t
dm_table_get_mode(struct dm_table
*t
);
460 struct mapped_device
*dm_table_get_md(struct dm_table
*t
);
465 void dm_table_event(struct dm_table
*t
);
468 * Run the queue for request-based targets.
470 void dm_table_run_md_queue_async(struct dm_table
*t
);
473 * The device must be suspended before calling this method.
474 * Returns the previous table, which the caller must destroy.
476 struct dm_table
*dm_swap_table(struct mapped_device
*md
,
480 * A wrapper around vmalloc.
482 void *dm_vcalloc(unsigned long nmemb
, unsigned long elem_size
);
484 /*-----------------------------------------------------------------
486 *---------------------------------------------------------------*/
487 #define DM_NAME "device-mapper"
490 extern struct ratelimit_state dm_ratelimit_state
;
492 #define dm_ratelimit() __ratelimit(&dm_ratelimit_state)
494 #define dm_ratelimit() 0
497 #define DMCRIT(f, arg...) \
498 printk(KERN_CRIT DM_NAME ": " DM_MSG_PREFIX ": " f "\n", ## arg)
500 #define DMERR(f, arg...) \
501 printk(KERN_ERR DM_NAME ": " DM_MSG_PREFIX ": " f "\n", ## arg)
502 #define DMERR_LIMIT(f, arg...) \
504 if (dm_ratelimit()) \
505 printk(KERN_ERR DM_NAME ": " DM_MSG_PREFIX ": " \
509 #define DMWARN(f, arg...) \
510 printk(KERN_WARNING DM_NAME ": " DM_MSG_PREFIX ": " f "\n", ## arg)
511 #define DMWARN_LIMIT(f, arg...) \
513 if (dm_ratelimit()) \
514 printk(KERN_WARNING DM_NAME ": " DM_MSG_PREFIX ": " \
518 #define DMINFO(f, arg...) \
519 printk(KERN_INFO DM_NAME ": " DM_MSG_PREFIX ": " f "\n", ## arg)
520 #define DMINFO_LIMIT(f, arg...) \
522 if (dm_ratelimit()) \
523 printk(KERN_INFO DM_NAME ": " DM_MSG_PREFIX ": " f \
527 #ifdef CONFIG_DM_DEBUG
528 # define DMDEBUG(f, arg...) \
529 printk(KERN_DEBUG DM_NAME ": " DM_MSG_PREFIX " DEBUG: " f "\n", ## arg)
530 # define DMDEBUG_LIMIT(f, arg...) \
532 if (dm_ratelimit()) \
533 printk(KERN_DEBUG DM_NAME ": " DM_MSG_PREFIX ": " f \
537 # define DMDEBUG(f, arg...) do {} while (0)
538 # define DMDEBUG_LIMIT(f, arg...) do {} while (0)
541 #define DMEMIT(x...) sz += ((sz >= maxlen) ? \
542 0 : scnprintf(result + sz, maxlen - sz, x))
544 #define SECTOR_SHIFT 9
547 * Definitions of return values from target end_io function.
549 #define DM_ENDIO_INCOMPLETE 1
550 #define DM_ENDIO_REQUEUE 2
553 * Definitions of return values from target map function.
555 #define DM_MAPIO_SUBMITTED 0
556 #define DM_MAPIO_REMAPPED 1
557 #define DM_MAPIO_REQUEUE DM_ENDIO_REQUEUE
559 #define dm_sector_div64(x, y)( \
562 (x) = div64_u64_rem(x, y, &_res); \
570 #define dm_div_up(n, sz) (((n) + (sz) - 1) / (sz))
572 #define dm_sector_div_up(n, sz) ( \
574 sector_t _r = ((n) + (sz) - 1); \
575 sector_div(_r, (sz)); \
581 * ceiling(n / size) * size
583 #define dm_round_up(n, sz) (dm_div_up((n), (sz)) * (sz))
585 #define dm_array_too_big(fixed, obj, num) \
586 ((num) > (UINT_MAX - (fixed)) / (obj))
589 * Sector offset taken relative to the start of the target instead of
590 * relative to the start of the device.
592 #define dm_target_offset(ti, sector) ((sector) - (ti)->begin)
594 static inline sector_t
to_sector(unsigned long n
)
596 return (n
>> SECTOR_SHIFT
);
599 static inline unsigned long to_bytes(sector_t n
)
601 return (n
<< SECTOR_SHIFT
);
604 #endif /* _LINUX_DEVICE_MAPPER_H */