| /* |
| * Copyright (C) 2001 Sistina Software (UK) Limited. |
| * Copyright (C) 2004-2008 Red Hat, Inc. All rights reserved. |
| * |
| * This file is released under the LGPL. |
| */ |
| |
| #ifndef _LINUX_DEVICE_MAPPER_H |
| #define _LINUX_DEVICE_MAPPER_H |
| |
| #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 { |
| DM_TYPE_NONE = 0, |
| DM_TYPE_BIO_BASED = 1, |
| DM_TYPE_REQUEST_BASED = 2, |
| DM_TYPE_MQ_REQUEST_BASED = 3, |
| DM_TYPE_DAX_BIO_BASED = 4, |
| }; |
| |
| 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, blk_status_t 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 0x00000002 |
| #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 0x00000020 |
| #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; |
| } |
| |
| 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)); |
| } |
| |
| 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; |
| } |
| |
| 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); |
| } |
| |
| static inline unsigned long to_bytes(sector_t n) |
| { |
| return (n << SECTOR_SHIFT); |
| } |
| |
| #endif /* _LINUX_DEVICE_MAPPER_H */ |