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/ratelimit.h>
21 typedef enum { STATUSTYPE_INFO
, STATUSTYPE_TABLE
} status_type_t
;
25 unsigned long long ll
;
26 unsigned target_request_nr
;
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 union map_info
*map_context
);
51 typedef int (*dm_map_request_fn
) (struct dm_target
*ti
, struct request
*clone
,
52 union map_info
*map_context
);
56 * < 0 : error (currently ignored)
57 * 0 : ended successfully
58 * 1 : for some reason the io has still not completed (eg,
59 * multipath target might want to requeue a failed io).
60 * 2 : The target wants to push back the io
62 typedef int (*dm_endio_fn
) (struct dm_target
*ti
,
63 struct bio
*bio
, int error
,
64 union map_info
*map_context
);
65 typedef int (*dm_request_endio_fn
) (struct dm_target
*ti
,
66 struct request
*clone
, int error
,
67 union map_info
*map_context
);
69 typedef void (*dm_presuspend_fn
) (struct dm_target
*ti
);
70 typedef void (*dm_postsuspend_fn
) (struct dm_target
*ti
);
71 typedef int (*dm_preresume_fn
) (struct dm_target
*ti
);
72 typedef void (*dm_resume_fn
) (struct dm_target
*ti
);
74 typedef int (*dm_status_fn
) (struct dm_target
*ti
, status_type_t status_type
,
75 unsigned status_flags
, char *result
, unsigned maxlen
);
77 typedef int (*dm_message_fn
) (struct dm_target
*ti
, unsigned argc
, char **argv
);
79 typedef int (*dm_ioctl_fn
) (struct dm_target
*ti
, unsigned int cmd
,
82 typedef int (*dm_merge_fn
) (struct dm_target
*ti
, struct bvec_merge_data
*bvm
,
83 struct bio_vec
*biovec
, int max_size
);
85 typedef int (*iterate_devices_callout_fn
) (struct dm_target
*ti
,
87 sector_t start
, sector_t len
,
90 typedef int (*dm_iterate_devices_fn
) (struct dm_target
*ti
,
91 iterate_devices_callout_fn fn
,
94 typedef void (*dm_io_hints_fn
) (struct dm_target
*ti
,
95 struct queue_limits
*limits
);
99 * 0: The target can handle the next I/O immediately.
100 * 1: The target can't handle the next I/O immediately.
102 typedef int (*dm_busy_fn
) (struct dm_target
*ti
);
104 void dm_error(const char *message
);
107 * Combine device limits.
109 int dm_set_device_limits(struct dm_target
*ti
, struct dm_dev
*dev
,
110 sector_t start
, sector_t len
, void *data
);
113 struct block_device
*bdev
;
119 * Constructors should call these functions to ensure destination devices
120 * are opened/closed correctly.
122 int dm_get_device(struct dm_target
*ti
, const char *path
, fmode_t mode
,
123 struct dm_dev
**result
);
124 void dm_put_device(struct dm_target
*ti
, struct dm_dev
*d
);
127 * Information about a target type
133 struct module
*module
;
138 dm_map_request_fn map_rq
;
140 dm_request_endio_fn rq_end_io
;
141 dm_presuspend_fn presuspend
;
142 dm_postsuspend_fn postsuspend
;
143 dm_preresume_fn preresume
;
146 dm_message_fn message
;
150 dm_iterate_devices_fn iterate_devices
;
151 dm_io_hints_fn io_hints
;
153 /* For internal device-mapper use. */
154 struct list_head list
;
162 * Any table that contains an instance of this target must have only one.
164 #define DM_TARGET_SINGLETON 0x00000001
165 #define dm_target_needs_singleton(type) ((type)->features & DM_TARGET_SINGLETON)
168 * Indicates that a target does not support read-only devices.
170 #define DM_TARGET_ALWAYS_WRITEABLE 0x00000002
171 #define dm_target_always_writeable(type) \
172 ((type)->features & DM_TARGET_ALWAYS_WRITEABLE)
175 * Any device that contains a table with an instance of this target may never
176 * have tables containing any different target type.
178 #define DM_TARGET_IMMUTABLE 0x00000004
179 #define dm_target_is_immutable(type) ((type)->features & DM_TARGET_IMMUTABLE)
182 struct dm_table
*table
;
183 struct target_type
*type
;
189 /* If non-zero, maximum size of I/O submitted to a target. */
193 * A number of zero-length barrier requests that will be submitted
194 * to the target for the purpose of flushing cache.
196 * The request number will be placed in union map_info->target_request_nr.
197 * It is a responsibility of the target driver to remap these requests
198 * to the real underlying devices.
200 unsigned num_flush_requests
;
203 * The number of discard requests that will be submitted to the
204 * target. map_info->request_nr is used just like num_flush_requests.
206 unsigned num_discard_requests
;
208 /* target specific data */
211 /* Used to provide an error string from the ctr */
215 * Set if this target needs to receive flushes regardless of
216 * whether or not its underlying devices have support.
218 bool flush_supported
:1;
221 * Set if this target needs to receive discards regardless of
222 * whether or not its underlying devices have support.
224 bool discards_supported
:1;
227 * Set if the target required discard request to be split
228 * on max_io_len boundary.
230 bool split_discard_requests
:1;
233 * Set if this target does not return zeroes on discarded blocks.
235 bool discard_zeroes_data_unsupported
:1;
238 /* Each target can link one of these into the table */
239 struct dm_target_callbacks
{
240 struct list_head list
;
241 int (*congested_fn
) (struct dm_target_callbacks
*, int);
244 int dm_register_target(struct target_type
*t
);
245 void dm_unregister_target(struct target_type
*t
);
248 * Target argument parsing.
256 * The minimum and maximum value of a numeric argument, together with
257 * the error message to use if the number is found to be outside that range.
266 * Validate the next argument, either returning it as *value or, if invalid,
267 * returning -EINVAL and setting *error.
269 int dm_read_arg(struct dm_arg
*arg
, struct dm_arg_set
*arg_set
,
270 unsigned *value
, char **error
);
273 * Process the next argument as the start of a group containing between
274 * arg->min and arg->max further arguments. Either return the size as
275 * *num_args or, if invalid, return -EINVAL and set *error.
277 int dm_read_arg_group(struct dm_arg
*arg
, struct dm_arg_set
*arg_set
,
278 unsigned *num_args
, char **error
);
281 * Return the current argument and shift to the next.
283 const char *dm_shift_arg(struct dm_arg_set
*as
);
286 * Move through num_args arguments.
288 void dm_consume_args(struct dm_arg_set
*as
, unsigned num_args
);
290 /*-----------------------------------------------------------------
291 * Functions for creating and manipulating mapped devices.
292 * Drop the reference with dm_put when you finish with the object.
293 *---------------------------------------------------------------*/
296 * DM_ANY_MINOR chooses the next available minor number.
298 #define DM_ANY_MINOR (-1)
299 int dm_create(int minor
, struct mapped_device
**md
);
302 * Reference counting for md.
304 struct mapped_device
*dm_get_md(dev_t dev
);
305 void dm_get(struct mapped_device
*md
);
306 void dm_put(struct mapped_device
*md
);
309 * An arbitrary pointer may be stored alongside a mapped device.
311 void dm_set_mdptr(struct mapped_device
*md
, void *ptr
);
312 void *dm_get_mdptr(struct mapped_device
*md
);
315 * A device can still be used while suspended, but I/O is deferred.
317 int dm_suspend(struct mapped_device
*md
, unsigned suspend_flags
);
318 int dm_resume(struct mapped_device
*md
);
323 uint32_t dm_get_event_nr(struct mapped_device
*md
);
324 int dm_wait_event(struct mapped_device
*md
, int event_nr
);
325 uint32_t dm_next_uevent_seq(struct mapped_device
*md
);
326 void dm_uevent_add(struct mapped_device
*md
, struct list_head
*elist
);
331 const char *dm_device_name(struct mapped_device
*md
);
332 int dm_copy_name_and_uuid(struct mapped_device
*md
, char *name
, char *uuid
);
333 struct gendisk
*dm_disk(struct mapped_device
*md
);
334 int dm_suspended(struct dm_target
*ti
);
335 int dm_noflush_suspending(struct dm_target
*ti
);
336 union map_info
*dm_get_mapinfo(struct bio
*bio
);
337 union map_info
*dm_get_rq_mapinfo(struct request
*rq
);
340 * Geometry functions.
342 int dm_get_geometry(struct mapped_device
*md
, struct hd_geometry
*geo
);
343 int dm_set_geometry(struct mapped_device
*md
, struct hd_geometry
*geo
);
346 /*-----------------------------------------------------------------
347 * Functions for manipulating device-mapper tables.
348 *---------------------------------------------------------------*/
351 * First create an empty table.
353 int dm_table_create(struct dm_table
**result
, fmode_t mode
,
354 unsigned num_targets
, struct mapped_device
*md
);
357 * Then call this once for each target.
359 int dm_table_add_target(struct dm_table
*t
, const char *type
,
360 sector_t start
, sector_t len
, char *params
);
363 * Target_ctr should call this if it needs to add any callbacks.
365 void dm_table_add_target_callbacks(struct dm_table
*t
, struct dm_target_callbacks
*cb
);
368 * Finally call this to make the table ready for use.
370 int dm_table_complete(struct dm_table
*t
);
373 * Target may require that it is never sent I/O larger than len.
375 int __must_check
dm_set_target_max_io_len(struct dm_target
*ti
, sector_t len
);
378 * Table reference counting.
380 struct dm_table
*dm_get_live_table(struct mapped_device
*md
);
381 void dm_table_get(struct dm_table
*t
);
382 void dm_table_put(struct dm_table
*t
);
387 sector_t
dm_table_get_size(struct dm_table
*t
);
388 unsigned int dm_table_get_num_targets(struct dm_table
*t
);
389 fmode_t
dm_table_get_mode(struct dm_table
*t
);
390 struct mapped_device
*dm_table_get_md(struct dm_table
*t
);
395 void dm_table_event(struct dm_table
*t
);
398 * The device must be suspended before calling this method.
399 * Returns the previous table, which the caller must destroy.
401 struct dm_table
*dm_swap_table(struct mapped_device
*md
,
405 * A wrapper around vmalloc.
407 void *dm_vcalloc(unsigned long nmemb
, unsigned long elem_size
);
409 /*-----------------------------------------------------------------
411 *---------------------------------------------------------------*/
412 #define DM_NAME "device-mapper"
415 extern struct ratelimit_state dm_ratelimit_state
;
417 #define dm_ratelimit() __ratelimit(&dm_ratelimit_state)
419 #define dm_ratelimit() 0
422 #define DMCRIT(f, arg...) \
423 printk(KERN_CRIT DM_NAME ": " DM_MSG_PREFIX ": " f "\n", ## arg)
425 #define DMERR(f, arg...) \
426 printk(KERN_ERR DM_NAME ": " DM_MSG_PREFIX ": " f "\n", ## arg)
427 #define DMERR_LIMIT(f, arg...) \
429 if (dm_ratelimit()) \
430 printk(KERN_ERR DM_NAME ": " DM_MSG_PREFIX ": " \
434 #define DMWARN(f, arg...) \
435 printk(KERN_WARNING DM_NAME ": " DM_MSG_PREFIX ": " f "\n", ## arg)
436 #define DMWARN_LIMIT(f, arg...) \
438 if (dm_ratelimit()) \
439 printk(KERN_WARNING DM_NAME ": " DM_MSG_PREFIX ": " \
443 #define DMINFO(f, arg...) \
444 printk(KERN_INFO DM_NAME ": " DM_MSG_PREFIX ": " f "\n", ## arg)
445 #define DMINFO_LIMIT(f, arg...) \
447 if (dm_ratelimit()) \
448 printk(KERN_INFO DM_NAME ": " DM_MSG_PREFIX ": " f \
452 #ifdef CONFIG_DM_DEBUG
453 # define DMDEBUG(f, arg...) \
454 printk(KERN_DEBUG DM_NAME ": " DM_MSG_PREFIX " DEBUG: " f "\n", ## arg)
455 # define DMDEBUG_LIMIT(f, arg...) \
457 if (dm_ratelimit()) \
458 printk(KERN_DEBUG DM_NAME ": " DM_MSG_PREFIX ": " f \
462 # define DMDEBUG(f, arg...) do {} while (0)
463 # define DMDEBUG_LIMIT(f, arg...) do {} while (0)
466 #define DMEMIT(x...) sz += ((sz >= maxlen) ? \
467 0 : scnprintf(result + sz, maxlen - sz, x))
469 #define SECTOR_SHIFT 9
472 * Definitions of return values from target end_io function.
474 #define DM_ENDIO_INCOMPLETE 1
475 #define DM_ENDIO_REQUEUE 2
478 * Definitions of return values from target map function.
480 #define DM_MAPIO_SUBMITTED 0
481 #define DM_MAPIO_REMAPPED 1
482 #define DM_MAPIO_REQUEUE DM_ENDIO_REQUEUE
487 #define dm_div_up(n, sz) (((n) + (sz) - 1) / (sz))
489 #define dm_sector_div_up(n, sz) ( \
491 sector_t _r = ((n) + (sz) - 1); \
492 sector_div(_r, (sz)); \
498 * ceiling(n / size) * size
500 #define dm_round_up(n, sz) (dm_div_up((n), (sz)) * (sz))
502 #define dm_array_too_big(fixed, obj, num) \
503 ((num) > (UINT_MAX - (fixed)) / (obj))
506 * Sector offset taken relative to the start of the target instead of
507 * relative to the start of the device.
509 #define dm_target_offset(ti, sector) ((sector) - (ti)->begin)
511 static inline sector_t
to_sector(unsigned long n
)
513 return (n
>> SECTOR_SHIFT
);
516 static inline unsigned long to_bytes(sector_t n
)
518 return (n
<< SECTOR_SHIFT
);
521 /*-----------------------------------------------------------------
522 * Helper for block layer and dm core operations
523 *---------------------------------------------------------------*/
524 void dm_dispatch_request(struct request
*rq
);
525 void dm_requeue_unmapped_request(struct request
*rq
);
526 void dm_kill_unmapped_request(struct request
*rq
, int error
);
527 int dm_underlying_device_busy(struct request_queue
*q
);
529 #endif /* _LINUX_DEVICE_MAPPER_H */