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
;
26 unsigned long long ll
;
30 * In the constructor the target parameter will already have the
31 * table, type, begin and len fields filled in.
33 typedef int (*dm_ctr_fn
) (struct dm_target
*target
,
34 unsigned int argc
, char **argv
);
37 * The destructor doesn't need to free the dm_target, just
38 * anything hidden ti->private.
40 typedef void (*dm_dtr_fn
) (struct dm_target
*ti
);
43 * The map function must return:
45 * = 0: The target will handle the io by resubmitting it later
46 * = 1: simple remap complete
47 * = 2: The target wants to push back the io
49 typedef int (*dm_map_fn
) (struct dm_target
*ti
, struct bio
*bio
);
50 typedef int (*dm_map_request_fn
) (struct dm_target
*ti
, struct request
*clone
,
51 union map_info
*map_context
);
55 * < 0 : error (currently ignored)
56 * 0 : ended successfully
57 * 1 : for some reason the io has still not completed (eg,
58 * multipath target might want to requeue a failed io).
59 * 2 : The target wants to push back the io
61 typedef int (*dm_endio_fn
) (struct dm_target
*ti
,
62 struct bio
*bio
, int error
);
63 typedef int (*dm_request_endio_fn
) (struct dm_target
*ti
,
64 struct request
*clone
, int error
,
65 union map_info
*map_context
);
67 typedef void (*dm_presuspend_fn
) (struct dm_target
*ti
);
68 typedef void (*dm_postsuspend_fn
) (struct dm_target
*ti
);
69 typedef int (*dm_preresume_fn
) (struct dm_target
*ti
);
70 typedef void (*dm_resume_fn
) (struct dm_target
*ti
);
72 typedef void (*dm_status_fn
) (struct dm_target
*ti
, status_type_t status_type
,
73 unsigned status_flags
, char *result
, unsigned maxlen
);
75 typedef int (*dm_message_fn
) (struct dm_target
*ti
, unsigned argc
, char **argv
);
77 typedef int (*dm_ioctl_fn
) (struct dm_target
*ti
, unsigned int cmd
,
80 typedef int (*dm_merge_fn
) (struct dm_target
*ti
, struct bvec_merge_data
*bvm
,
81 struct bio_vec
*biovec
, int max_size
);
84 * These iteration functions are typically used to check (and combine)
85 * properties of underlying devices.
86 * E.g. Does at least one underlying device support flush?
87 * Does any underlying device not support WRITE_SAME?
89 * The callout function is called once for each contiguous section of
90 * an underlying device. State can be maintained in *data.
91 * Return non-zero to stop iterating through any further devices.
93 typedef int (*iterate_devices_callout_fn
) (struct dm_target
*ti
,
95 sector_t start
, sector_t len
,
99 * This function must iterate through each section of device used by the
100 * target until it encounters a non-zero return code, which it then returns.
101 * Returns zero if no callout returned non-zero.
103 typedef int (*dm_iterate_devices_fn
) (struct dm_target
*ti
,
104 iterate_devices_callout_fn fn
,
107 typedef void (*dm_io_hints_fn
) (struct dm_target
*ti
,
108 struct queue_limits
*limits
);
112 * 0: The target can handle the next I/O immediately.
113 * 1: The target can't handle the next I/O immediately.
115 typedef int (*dm_busy_fn
) (struct dm_target
*ti
);
117 void dm_error(const char *message
);
120 * Combine device limits.
122 int dm_set_device_limits(struct dm_target
*ti
, struct dm_dev
*dev
,
123 sector_t start
, sector_t len
, void *data
);
126 struct block_device
*bdev
;
132 * Constructors should call these functions to ensure destination devices
133 * are opened/closed correctly.
135 int dm_get_device(struct dm_target
*ti
, const char *path
, fmode_t mode
,
136 struct dm_dev
**result
);
137 void dm_put_device(struct dm_target
*ti
, struct dm_dev
*d
);
140 * Information about a target type
146 struct module
*module
;
151 dm_map_request_fn map_rq
;
153 dm_request_endio_fn rq_end_io
;
154 dm_presuspend_fn presuspend
;
155 dm_postsuspend_fn postsuspend
;
156 dm_preresume_fn preresume
;
159 dm_message_fn message
;
163 dm_iterate_devices_fn iterate_devices
;
164 dm_io_hints_fn io_hints
;
166 /* For internal device-mapper use. */
167 struct list_head list
;
175 * Any table that contains an instance of this target must have only one.
177 #define DM_TARGET_SINGLETON 0x00000001
178 #define dm_target_needs_singleton(type) ((type)->features & DM_TARGET_SINGLETON)
181 * Indicates that a target does not support read-only devices.
183 #define DM_TARGET_ALWAYS_WRITEABLE 0x00000002
184 #define dm_target_always_writeable(type) \
185 ((type)->features & DM_TARGET_ALWAYS_WRITEABLE)
188 * Any device that contains a table with an instance of this target may never
189 * have tables containing any different target type.
191 #define DM_TARGET_IMMUTABLE 0x00000004
192 #define dm_target_is_immutable(type) ((type)->features & DM_TARGET_IMMUTABLE)
195 * Some targets need to be sent the same WRITE bio severals times so
196 * that they can send copies of it to different devices. This function
197 * examines any supplied bio and returns the number of copies of it the
200 typedef unsigned (*dm_num_write_bios_fn
) (struct dm_target
*ti
, struct bio
*bio
);
203 struct dm_table
*table
;
204 struct target_type
*type
;
210 /* If non-zero, maximum size of I/O submitted to a target. */
214 * A number of zero-length barrier bios that will be submitted
215 * to the target for the purpose of flushing cache.
217 * The bio number can be accessed with dm_bio_get_target_bio_nr.
218 * It is a responsibility of the target driver to remap these bios
219 * to the real underlying devices.
221 unsigned num_flush_bios
;
224 * The number of discard bios that will be submitted to the target.
225 * The bio number can be accessed with dm_bio_get_target_bio_nr.
227 unsigned num_discard_bios
;
230 * The number of WRITE SAME bios that will be submitted to the target.
231 * The bio number can be accessed with dm_bio_get_target_bio_nr.
233 unsigned num_write_same_bios
;
236 * The minimum number of extra bytes allocated in each bio for the
237 * target to use. dm_per_bio_data returns the data location.
239 unsigned per_bio_data_size
;
242 * If defined, this function is called to find out how many
243 * duplicate bios should be sent to the target when writing
246 dm_num_write_bios_fn num_write_bios
;
248 /* target specific data */
251 /* Used to provide an error string from the ctr */
255 * Set if this target needs to receive flushes regardless of
256 * whether or not its underlying devices have support.
258 bool flush_supported
:1;
261 * Set if this target needs to receive discards regardless of
262 * whether or not its underlying devices have support.
264 bool discards_supported
:1;
267 * Set if the target required discard bios to be split
268 * on max_io_len boundary.
270 bool split_discard_bios
:1;
273 * Set if this target does not return zeroes on discarded blocks.
275 bool discard_zeroes_data_unsupported
:1;
278 /* Each target can link one of these into the table */
279 struct dm_target_callbacks
{
280 struct list_head list
;
281 int (*congested_fn
) (struct dm_target_callbacks
*, int);
286 * One of these is allocated for each bio.
287 * This structure shouldn't be touched directly by target drivers.
288 * It is here so that we can inline dm_per_bio_data and
289 * dm_bio_from_per_bio_data
291 struct dm_target_io
{
293 struct dm_target
*ti
;
295 unsigned target_bio_nr
;
299 static inline void *dm_per_bio_data(struct bio
*bio
, size_t data_size
)
301 return (char *)bio
- offsetof(struct dm_target_io
, clone
) - data_size
;
304 static inline struct bio
*dm_bio_from_per_bio_data(void *data
, size_t data_size
)
306 return (struct bio
*)((char *)data
+ data_size
+ offsetof(struct dm_target_io
, clone
));
309 static inline unsigned dm_bio_get_target_bio_nr(const struct bio
*bio
)
311 return container_of(bio
, struct dm_target_io
, clone
)->target_bio_nr
;
314 int dm_register_target(struct target_type
*t
);
315 void dm_unregister_target(struct target_type
*t
);
318 * Target argument parsing.
326 * The minimum and maximum value of a numeric argument, together with
327 * the error message to use if the number is found to be outside that range.
336 * Validate the next argument, either returning it as *value or, if invalid,
337 * returning -EINVAL and setting *error.
339 int dm_read_arg(struct dm_arg
*arg
, struct dm_arg_set
*arg_set
,
340 unsigned *value
, char **error
);
343 * Process the next argument as the start of a group containing between
344 * arg->min and arg->max further arguments. Either return the size as
345 * *num_args or, if invalid, return -EINVAL and set *error.
347 int dm_read_arg_group(struct dm_arg
*arg
, struct dm_arg_set
*arg_set
,
348 unsigned *num_args
, char **error
);
351 * Return the current argument and shift to the next.
353 const char *dm_shift_arg(struct dm_arg_set
*as
);
356 * Move through num_args arguments.
358 void dm_consume_args(struct dm_arg_set
*as
, unsigned num_args
);
360 /*-----------------------------------------------------------------
361 * Functions for creating and manipulating mapped devices.
362 * Drop the reference with dm_put when you finish with the object.
363 *---------------------------------------------------------------*/
366 * DM_ANY_MINOR chooses the next available minor number.
368 #define DM_ANY_MINOR (-1)
369 int dm_create(int minor
, struct mapped_device
**md
);
372 * Reference counting for md.
374 struct mapped_device
*dm_get_md(dev_t dev
);
375 void dm_get(struct mapped_device
*md
);
376 void dm_put(struct mapped_device
*md
);
379 * An arbitrary pointer may be stored alongside a mapped device.
381 void dm_set_mdptr(struct mapped_device
*md
, void *ptr
);
382 void *dm_get_mdptr(struct mapped_device
*md
);
385 * A device can still be used while suspended, but I/O is deferred.
387 int dm_suspend(struct mapped_device
*md
, unsigned suspend_flags
);
388 int dm_resume(struct mapped_device
*md
);
393 uint32_t dm_get_event_nr(struct mapped_device
*md
);
394 int dm_wait_event(struct mapped_device
*md
, int event_nr
);
395 uint32_t dm_next_uevent_seq(struct mapped_device
*md
);
396 void dm_uevent_add(struct mapped_device
*md
, struct list_head
*elist
);
401 const char *dm_device_name(struct mapped_device
*md
);
402 int dm_copy_name_and_uuid(struct mapped_device
*md
, char *name
, char *uuid
);
403 struct gendisk
*dm_disk(struct mapped_device
*md
);
404 int dm_suspended(struct dm_target
*ti
);
405 int dm_noflush_suspending(struct dm_target
*ti
);
406 union map_info
*dm_get_mapinfo(struct bio
*bio
);
407 union map_info
*dm_get_rq_mapinfo(struct request
*rq
);
409 struct queue_limits
*dm_get_queue_limits(struct mapped_device
*md
);
412 * Geometry functions.
414 int dm_get_geometry(struct mapped_device
*md
, struct hd_geometry
*geo
);
415 int dm_set_geometry(struct mapped_device
*md
, struct hd_geometry
*geo
);
417 /*-----------------------------------------------------------------
418 * Functions for manipulating device-mapper tables.
419 *---------------------------------------------------------------*/
422 * First create an empty table.
424 int dm_table_create(struct dm_table
**result
, fmode_t mode
,
425 unsigned num_targets
, struct mapped_device
*md
);
428 * Then call this once for each target.
430 int dm_table_add_target(struct dm_table
*t
, const char *type
,
431 sector_t start
, sector_t len
, char *params
);
434 * Target_ctr should call this if it needs to add any callbacks.
436 void dm_table_add_target_callbacks(struct dm_table
*t
, struct dm_target_callbacks
*cb
);
439 * Finally call this to make the table ready for use.
441 int dm_table_complete(struct dm_table
*t
);
444 * Target may require that it is never sent I/O larger than len.
446 int __must_check
dm_set_target_max_io_len(struct dm_target
*ti
, sector_t len
);
449 * Table reference counting.
451 struct dm_table
*dm_get_live_table(struct mapped_device
*md
, int *srcu_idx
);
452 void dm_put_live_table(struct mapped_device
*md
, int srcu_idx
);
453 void dm_sync_table(struct mapped_device
*md
);
458 sector_t
dm_table_get_size(struct dm_table
*t
);
459 unsigned int dm_table_get_num_targets(struct dm_table
*t
);
460 fmode_t
dm_table_get_mode(struct dm_table
*t
);
461 struct mapped_device
*dm_table_get_md(struct dm_table
*t
);
466 void dm_table_event(struct dm_table
*t
);
469 * The device must be suspended before calling this method.
470 * Returns the previous table, which the caller must destroy.
472 struct dm_table
*dm_swap_table(struct mapped_device
*md
,
476 * A wrapper around vmalloc.
478 void *dm_vcalloc(unsigned long nmemb
, unsigned long elem_size
);
480 /*-----------------------------------------------------------------
482 *---------------------------------------------------------------*/
483 #define DM_NAME "device-mapper"
486 extern struct ratelimit_state dm_ratelimit_state
;
488 #define dm_ratelimit() __ratelimit(&dm_ratelimit_state)
490 #define dm_ratelimit() 0
493 #define DMCRIT(f, arg...) \
494 printk(KERN_CRIT DM_NAME ": " DM_MSG_PREFIX ": " f "\n", ## arg)
496 #define DMERR(f, arg...) \
497 printk(KERN_ERR DM_NAME ": " DM_MSG_PREFIX ": " f "\n", ## arg)
498 #define DMERR_LIMIT(f, arg...) \
500 if (dm_ratelimit()) \
501 printk(KERN_ERR DM_NAME ": " DM_MSG_PREFIX ": " \
505 #define DMWARN(f, arg...) \
506 printk(KERN_WARNING DM_NAME ": " DM_MSG_PREFIX ": " f "\n", ## arg)
507 #define DMWARN_LIMIT(f, arg...) \
509 if (dm_ratelimit()) \
510 printk(KERN_WARNING DM_NAME ": " DM_MSG_PREFIX ": " \
514 #define DMINFO(f, arg...) \
515 printk(KERN_INFO DM_NAME ": " DM_MSG_PREFIX ": " f "\n", ## arg)
516 #define DMINFO_LIMIT(f, arg...) \
518 if (dm_ratelimit()) \
519 printk(KERN_INFO DM_NAME ": " DM_MSG_PREFIX ": " f \
523 #ifdef CONFIG_DM_DEBUG
524 # define DMDEBUG(f, arg...) \
525 printk(KERN_DEBUG DM_NAME ": " DM_MSG_PREFIX " DEBUG: " f "\n", ## arg)
526 # define DMDEBUG_LIMIT(f, arg...) \
528 if (dm_ratelimit()) \
529 printk(KERN_DEBUG DM_NAME ": " DM_MSG_PREFIX ": " f \
533 # define DMDEBUG(f, arg...) do {} while (0)
534 # define DMDEBUG_LIMIT(f, arg...) do {} while (0)
537 #define DMEMIT(x...) sz += ((sz >= maxlen) ? \
538 0 : scnprintf(result + sz, maxlen - sz, x))
540 #define SECTOR_SHIFT 9
543 * Definitions of return values from target end_io function.
545 #define DM_ENDIO_INCOMPLETE 1
546 #define DM_ENDIO_REQUEUE 2
549 * Definitions of return values from target map function.
551 #define DM_MAPIO_SUBMITTED 0
552 #define DM_MAPIO_REMAPPED 1
553 #define DM_MAPIO_REQUEUE DM_ENDIO_REQUEUE
555 #define dm_sector_div64(x, y)( \
558 (x) = div64_u64_rem(x, y, &_res); \
566 #define dm_div_up(n, sz) (((n) + (sz) - 1) / (sz))
568 #define dm_sector_div_up(n, sz) ( \
570 sector_t _r = ((n) + (sz) - 1); \
571 sector_div(_r, (sz)); \
577 * ceiling(n / size) * size
579 #define dm_round_up(n, sz) (dm_div_up((n), (sz)) * (sz))
581 #define dm_array_too_big(fixed, obj, num) \
582 ((num) > (UINT_MAX - (fixed)) / (obj))
585 * Sector offset taken relative to the start of the target instead of
586 * relative to the start of the device.
588 #define dm_target_offset(ti, sector) ((sector) - (ti)->begin)
590 static inline sector_t
to_sector(unsigned long n
)
592 return (n
>> SECTOR_SHIFT
);
595 static inline unsigned long to_bytes(sector_t n
)
597 return (n
<< SECTOR_SHIFT
);
600 /*-----------------------------------------------------------------
601 * Helper for block layer and dm core operations
602 *---------------------------------------------------------------*/
603 void dm_dispatch_request(struct request
*rq
);
604 void dm_requeue_unmapped_request(struct request
*rq
);
605 void dm_kill_unmapped_request(struct request
*rq
, int error
);
606 int dm_underlying_device_busy(struct request_queue
*q
);
608 #endif /* _LINUX_DEVICE_MAPPER_H */