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;
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 union map_info *map_context);
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 union map_info *map_context);
64 typedef int (*dm_request_endio_fn) (struct dm_target *ti,
65 struct request *clone, int error,
66 union map_info *map_context);
68 typedef void (*dm_presuspend_fn) (struct dm_target *ti);
69 typedef void (*dm_postsuspend_fn) (struct dm_target *ti);
70 typedef int (*dm_preresume_fn) (struct dm_target *ti);
71 typedef void (*dm_resume_fn) (struct dm_target *ti);
73 typedef int (*dm_status_fn) (struct dm_target *ti, status_type_t status_type,
74 unsigned status_flags, char *result, unsigned maxlen);
76 typedef int (*dm_message_fn) (struct dm_target *ti, unsigned argc, char **argv);
78 typedef int (*dm_ioctl_fn) (struct dm_target *ti, unsigned int cmd,
81 typedef int (*dm_merge_fn) (struct dm_target *ti, struct bvec_merge_data *bvm,
82 struct bio_vec *biovec, int max_size);
84 typedef int (*iterate_devices_callout_fn) (struct dm_target *ti,
86 sector_t start, sector_t len,
89 typedef int (*dm_iterate_devices_fn) (struct dm_target *ti,
90 iterate_devices_callout_fn fn,
93 typedef void (*dm_io_hints_fn) (struct dm_target *ti,
94 struct queue_limits *limits);
98 * 0: The target can handle the next I/O immediately.
99 * 1: The target can't handle the next I/O immediately.
101 typedef int (*dm_busy_fn) (struct dm_target *ti);
103 void dm_error(const char *message);
106 * Combine device limits.
108 int dm_set_device_limits(struct dm_target *ti, struct dm_dev *dev,
109 sector_t start, sector_t len, void *data);
112 struct block_device *bdev;
118 * Constructors should call these functions to ensure destination devices
119 * are opened/closed correctly.
121 int dm_get_device(struct dm_target *ti, const char *path, fmode_t mode,
122 struct dm_dev **result);
123 void dm_put_device(struct dm_target *ti, struct dm_dev *d);
126 * Information about a target type
132 struct module *module;
137 dm_map_request_fn map_rq;
139 dm_request_endio_fn rq_end_io;
140 dm_presuspend_fn presuspend;
141 dm_postsuspend_fn postsuspend;
142 dm_preresume_fn preresume;
145 dm_message_fn message;
149 dm_iterate_devices_fn iterate_devices;
150 dm_io_hints_fn io_hints;
152 /* For internal device-mapper use. */
153 struct list_head list;
161 * Any table that contains an instance of this target must have only one.
163 #define DM_TARGET_SINGLETON 0x00000001
164 #define dm_target_needs_singleton(type) ((type)->features & DM_TARGET_SINGLETON)
167 * Indicates that a target does not support read-only devices.
169 #define DM_TARGET_ALWAYS_WRITEABLE 0x00000002
170 #define dm_target_always_writeable(type) \
171 ((type)->features & DM_TARGET_ALWAYS_WRITEABLE)
174 * Any device that contains a table with an instance of this target may never
175 * have tables containing any different target type.
177 #define DM_TARGET_IMMUTABLE 0x00000004
178 #define dm_target_is_immutable(type) ((type)->features & DM_TARGET_IMMUTABLE)
181 struct dm_table *table;
182 struct target_type *type;
188 /* If non-zero, maximum size of I/O submitted to a target. */
192 * A number of zero-length barrier requests that will be submitted
193 * to the target for the purpose of flushing cache.
195 * The request number can be accessed with dm_bio_get_target_request_nr.
196 * It is a responsibility of the target driver to remap these requests
197 * to the real underlying devices.
199 unsigned num_flush_requests;
202 * The number of discard requests that will be submitted to the target.
203 * The request number can be accessed with dm_bio_get_target_request_nr.
205 unsigned num_discard_requests;
208 * The number of WRITE SAME requests that will be submitted to the target.
209 * The request number can be accessed with dm_bio_get_target_request_nr.
211 unsigned num_write_same_requests;
214 * The minimum number of extra bytes allocated in each bio for the
215 * target to use. dm_per_bio_data returns the data location.
217 unsigned per_bio_data_size;
219 /* target specific data */
222 /* Used to provide an error string from the ctr */
226 * Set if this target needs to receive flushes regardless of
227 * whether or not its underlying devices have support.
229 bool flush_supported:1;
232 * Set if this target needs to receive discards regardless of
233 * whether or not its underlying devices have support.
235 bool discards_supported:1;
238 * Set if the target required discard request to be split
239 * on max_io_len boundary.
241 bool split_discard_requests:1;
244 * Set if this target does not return zeroes on discarded blocks.
246 bool discard_zeroes_data_unsupported:1;
249 /* Each target can link one of these into the table */
250 struct dm_target_callbacks {
251 struct list_head list;
252 int (*congested_fn) (struct dm_target_callbacks *, int);
257 * One of these is allocated for each bio.
258 * This structure shouldn't be touched directly by target drivers.
259 * It is here so that we can inline dm_per_bio_data and
260 * dm_bio_from_per_bio_data
262 struct dm_target_io {
264 struct dm_target *ti;
266 unsigned target_request_nr;
270 static inline void *dm_per_bio_data(struct bio *bio, size_t data_size)
272 return (char *)bio - offsetof(struct dm_target_io, clone) - data_size;
275 static inline struct bio *dm_bio_from_per_bio_data(void *data, size_t data_size)
277 return (struct bio *)((char *)data + data_size + offsetof(struct dm_target_io, clone));
280 static inline unsigned dm_bio_get_target_request_nr(const struct bio *bio)
282 return container_of(bio, struct dm_target_io, clone)->target_request_nr;
285 int dm_register_target(struct target_type *t);
286 void dm_unregister_target(struct target_type *t);
289 * Target argument parsing.
297 * The minimum and maximum value of a numeric argument, together with
298 * the error message to use if the number is found to be outside that range.
307 * Validate the next argument, either returning it as *value or, if invalid,
308 * returning -EINVAL and setting *error.
310 int dm_read_arg(struct dm_arg *arg, struct dm_arg_set *arg_set,
311 unsigned *value, char **error);
314 * Process the next argument as the start of a group containing between
315 * arg->min and arg->max further arguments. Either return the size as
316 * *num_args or, if invalid, return -EINVAL and set *error.
318 int dm_read_arg_group(struct dm_arg *arg, struct dm_arg_set *arg_set,
319 unsigned *num_args, char **error);
322 * Return the current argument and shift to the next.
324 const char *dm_shift_arg(struct dm_arg_set *as);
327 * Move through num_args arguments.
329 void dm_consume_args(struct dm_arg_set *as, unsigned num_args);
331 /*-----------------------------------------------------------------
332 * Functions for creating and manipulating mapped devices.
333 * Drop the reference with dm_put when you finish with the object.
334 *---------------------------------------------------------------*/
337 * DM_ANY_MINOR chooses the next available minor number.
339 #define DM_ANY_MINOR (-1)
340 int dm_create(int minor, struct mapped_device **md);
343 * Reference counting for md.
345 struct mapped_device *dm_get_md(dev_t dev);
346 void dm_get(struct mapped_device *md);
347 void dm_put(struct mapped_device *md);
350 * An arbitrary pointer may be stored alongside a mapped device.
352 void dm_set_mdptr(struct mapped_device *md, void *ptr);
353 void *dm_get_mdptr(struct mapped_device *md);
356 * A device can still be used while suspended, but I/O is deferred.
358 int dm_suspend(struct mapped_device *md, unsigned suspend_flags);
359 int dm_resume(struct mapped_device *md);
364 uint32_t dm_get_event_nr(struct mapped_device *md);
365 int dm_wait_event(struct mapped_device *md, int event_nr);
366 uint32_t dm_next_uevent_seq(struct mapped_device *md);
367 void dm_uevent_add(struct mapped_device *md, struct list_head *elist);
372 const char *dm_device_name(struct mapped_device *md);
373 int dm_copy_name_and_uuid(struct mapped_device *md, char *name, char *uuid);
374 struct gendisk *dm_disk(struct mapped_device *md);
375 int dm_suspended(struct dm_target *ti);
376 int dm_noflush_suspending(struct dm_target *ti);
377 union map_info *dm_get_mapinfo(struct bio *bio);
378 union map_info *dm_get_rq_mapinfo(struct request *rq);
381 * Geometry functions.
383 int dm_get_geometry(struct mapped_device *md, struct hd_geometry *geo);
384 int dm_set_geometry(struct mapped_device *md, struct hd_geometry *geo);
387 /*-----------------------------------------------------------------
388 * Functions for manipulating device-mapper tables.
389 *---------------------------------------------------------------*/
392 * First create an empty table.
394 int dm_table_create(struct dm_table **result, fmode_t mode,
395 unsigned num_targets, struct mapped_device *md);
398 * Then call this once for each target.
400 int dm_table_add_target(struct dm_table *t, const char *type,
401 sector_t start, sector_t len, char *params);
404 * Target_ctr should call this if it needs to add any callbacks.
406 void dm_table_add_target_callbacks(struct dm_table *t, struct dm_target_callbacks *cb);
409 * Finally call this to make the table ready for use.
411 int dm_table_complete(struct dm_table *t);
414 * Target may require that it is never sent I/O larger than len.
416 int __must_check dm_set_target_max_io_len(struct dm_target *ti, sector_t len);
419 * Table reference counting.
421 struct dm_table *dm_get_live_table(struct mapped_device *md);
422 void dm_table_get(struct dm_table *t);
423 void dm_table_put(struct dm_table *t);
428 sector_t dm_table_get_size(struct dm_table *t);
429 unsigned int dm_table_get_num_targets(struct dm_table *t);
430 fmode_t dm_table_get_mode(struct dm_table *t);
431 struct mapped_device *dm_table_get_md(struct dm_table *t);
436 void dm_table_event(struct dm_table *t);
439 * The device must be suspended before calling this method.
440 * Returns the previous table, which the caller must destroy.
442 struct dm_table *dm_swap_table(struct mapped_device *md,
446 * A wrapper around vmalloc.
448 void *dm_vcalloc(unsigned long nmemb, unsigned long elem_size);
450 /*-----------------------------------------------------------------
452 *---------------------------------------------------------------*/
453 #define DM_NAME "device-mapper"
456 extern struct ratelimit_state dm_ratelimit_state;
458 #define dm_ratelimit() __ratelimit(&dm_ratelimit_state)
460 #define dm_ratelimit() 0
463 #define DMCRIT(f, arg...) \
464 printk(KERN_CRIT DM_NAME ": " DM_MSG_PREFIX ": " f "\n", ## arg)
466 #define DMERR(f, arg...) \
467 printk(KERN_ERR DM_NAME ": " DM_MSG_PREFIX ": " f "\n", ## arg)
468 #define DMERR_LIMIT(f, arg...) \
470 if (dm_ratelimit()) \
471 printk(KERN_ERR DM_NAME ": " DM_MSG_PREFIX ": " \
475 #define DMWARN(f, arg...) \
476 printk(KERN_WARNING DM_NAME ": " DM_MSG_PREFIX ": " f "\n", ## arg)
477 #define DMWARN_LIMIT(f, arg...) \
479 if (dm_ratelimit()) \
480 printk(KERN_WARNING DM_NAME ": " DM_MSG_PREFIX ": " \
484 #define DMINFO(f, arg...) \
485 printk(KERN_INFO DM_NAME ": " DM_MSG_PREFIX ": " f "\n", ## arg)
486 #define DMINFO_LIMIT(f, arg...) \
488 if (dm_ratelimit()) \
489 printk(KERN_INFO DM_NAME ": " DM_MSG_PREFIX ": " f \
493 #ifdef CONFIG_DM_DEBUG
494 # define DMDEBUG(f, arg...) \
495 printk(KERN_DEBUG DM_NAME ": " DM_MSG_PREFIX " DEBUG: " f "\n", ## arg)
496 # define DMDEBUG_LIMIT(f, arg...) \
498 if (dm_ratelimit()) \
499 printk(KERN_DEBUG DM_NAME ": " DM_MSG_PREFIX ": " f \
503 # define DMDEBUG(f, arg...) do {} while (0)
504 # define DMDEBUG_LIMIT(f, arg...) do {} while (0)
507 #define DMEMIT(x...) sz += ((sz >= maxlen) ? \
508 0 : scnprintf(result + sz, maxlen - sz, x))
510 #define SECTOR_SHIFT 9
513 * Definitions of return values from target end_io function.
515 #define DM_ENDIO_INCOMPLETE 1
516 #define DM_ENDIO_REQUEUE 2
519 * Definitions of return values from target map function.
521 #define DM_MAPIO_SUBMITTED 0
522 #define DM_MAPIO_REMAPPED 1
523 #define DM_MAPIO_REQUEUE DM_ENDIO_REQUEUE
528 #define dm_div_up(n, sz) (((n) + (sz) - 1) / (sz))
530 #define dm_sector_div_up(n, sz) ( \
532 sector_t _r = ((n) + (sz) - 1); \
533 sector_div(_r, (sz)); \
539 * ceiling(n / size) * size
541 #define dm_round_up(n, sz) (dm_div_up((n), (sz)) * (sz))
543 #define dm_array_too_big(fixed, obj, num) \
544 ((num) > (UINT_MAX - (fixed)) / (obj))
547 * Sector offset taken relative to the start of the target instead of
548 * relative to the start of the device.
550 #define dm_target_offset(ti, sector) ((sector) - (ti)->begin)
552 static inline sector_t to_sector(unsigned long n)
554 return (n >> SECTOR_SHIFT);
557 static inline unsigned long to_bytes(sector_t n)
559 return (n << SECTOR_SHIFT);
562 /*-----------------------------------------------------------------
563 * Helper for block layer and dm core operations
564 *---------------------------------------------------------------*/
565 void dm_dispatch_request(struct request *rq);
566 void dm_requeue_unmapped_request(struct request *rq);
567 void dm_kill_unmapped_request(struct request *rq, int error);
568 int dm_underlying_device_busy(struct request_queue *q);
570 #endif /* _LINUX_DEVICE_MAPPER_H */