diff options
Diffstat (limited to 'include/linux/device-mapper.h')
| -rw-r--r-- | include/linux/device-mapper.h | 446 |
1 files changed, 396 insertions, 50 deletions
diff --git a/include/linux/device-mapper.h b/include/linux/device-mapper.h index cb784579956..e1707de043a 100644 --- a/include/linux/device-mapper.h +++ b/include/linux/device-mapper.h @@ -1,6 +1,6 @@ /* * Copyright (C) 2001 Sistina Software (UK) Limited. - * Copyright (C) 2004 Red Hat, Inc. All rights reserved. + * Copyright (C) 2004-2008 Red Hat, Inc. All rights reserved. * * This file is released under the LGPL. */ @@ -8,18 +8,21 @@ #ifndef _LINUX_DEVICE_MAPPER_H #define _LINUX_DEVICE_MAPPER_H -#ifdef __KERNEL__ +#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 dm_dev; struct mapped_device; +struct bio_vec; typedef enum { STATUSTYPE_INFO, STATUSTYPE_TABLE } status_type_t; union map_info { void *ptr; - unsigned long long ll; }; /* @@ -42,8 +45,9 @@ typedef void (*dm_dtr_fn) (struct dm_target *ti); * = 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, - union map_info *map_context); +typedef int (*dm_map_fn) (struct dm_target *ti, struct bio *bio); +typedef int (*dm_map_request_fn) (struct dm_target *ti, struct request *clone, + union map_info *map_context); /* * Returns: @@ -54,52 +58,92 @@ typedef int (*dm_map_fn) (struct dm_target *ti, struct bio *bio, * 2 : The target wants to push back the io */ typedef int (*dm_endio_fn) (struct dm_target *ti, - struct bio *bio, int error, - union map_info *map_context); + struct bio *bio, int error); +typedef int (*dm_request_endio_fn) (struct dm_target *ti, + struct request *clone, int error, + union map_info *map_context); -typedef void (*dm_flush_fn) (struct dm_target *ti); typedef void (*dm_presuspend_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 int (*dm_status_fn) (struct dm_target *ti, status_type_t status_type, - char *result, unsigned int maxlen); +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_ioctl_fn) (struct dm_target *ti, struct inode *inode, - struct file *filp, unsigned int cmd, +typedef int (*dm_ioctl_fn) (struct dm_target *ti, unsigned int cmd, unsigned long arg); -void dm_error(const char *message); +typedef int (*dm_merge_fn) (struct dm_target *ti, struct bvec_merge_data *bvm, + struct bio_vec *biovec, int max_size); + +/* + * 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); /* - * Combine device limits. + * Returns: + * 0: The target can handle the next I/O immediately. + * 1: The target can't handle the next I/O immediately. */ -void dm_set_device_limits(struct dm_target *ti, struct block_device *bdev); +typedef int (*dm_busy_fn) (struct dm_target *ti); + +void dm_error(const char *message); + +struct dm_dev { + struct block_device *bdev; + fmode_t mode; + char name[16]; +}; /* * Constructors should call these functions to ensure destination devices * are opened/closed correctly. - * FIXME: too many arguments. */ -int dm_get_device(struct dm_target *ti, const char *path, sector_t start, - sector_t len, int mode, struct dm_dev **result); +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_map_request_fn map_rq; dm_endio_fn end_io; - dm_flush_fn flush; + dm_request_endio_fn rq_end_io; dm_presuspend_fn presuspend; dm_postsuspend_fn postsuspend; dm_preresume_fn preresume; @@ -107,20 +151,47 @@ struct target_type { dm_status_fn status; dm_message_fn message; dm_ioctl_fn ioctl; -}; + dm_merge_fn merge; + dm_busy_fn busy; + dm_iterate_devices_fn iterate_devices; + dm_io_hints_fn io_hints; -struct io_restrictions { - unsigned long bounce_pfn; - unsigned long seg_boundary_mask; - unsigned max_hw_sectors; - unsigned max_sectors; - unsigned max_segment_size; - unsigned short hardsect_size; - unsigned short max_hw_segments; - unsigned short max_phys_segments; - unsigned char no_cluster; /* inverted so that 0 is default */ + /* 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) + +/* + * 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); + struct dm_target { struct dm_table *table; struct target_type *type; @@ -129,26 +200,155 @@ struct dm_target { sector_t begin; sector_t len; - /* FIXME: turn this into a mask, and merge with io_restrictions */ - /* Always a power of 2 */ - sector_t split_io; + /* 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; /* - * These are automatically filled in by - * dm_table_get_device. + * 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. */ - struct io_restrictions limits; + unsigned num_write_same_bios; + + /* + * The minimum number of extra bytes allocated in each bio for the + * target to use. dm_per_bio_data returns the data location. + */ + unsigned per_bio_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; + + /* + * Set if this target does not return zeroes on discarded blocks. + */ + bool discard_zeroes_data_unsupported: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); -int dm_unregister_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. @@ -194,8 +394,12 @@ void dm_uevent_add(struct mapped_device *md, struct list_head *elist); 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 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. @@ -203,7 +407,6 @@ int dm_noflush_suspending(struct dm_target *ti); 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. *---------------------------------------------------------------*/ @@ -211,7 +414,7 @@ int dm_set_geometry(struct mapped_device *md, struct hd_geometry *geo); /* * First create an empty table. */ -int dm_table_create(struct dm_table **result, int mode, +int dm_table_create(struct dm_table **result, fmode_t mode, unsigned num_targets, struct mapped_device *md); /* @@ -221,23 +424,33 @@ 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); + +/* * 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_table(struct mapped_device *md); -void dm_table_get(struct dm_table *t); -void dm_table_put(struct dm_table *t); +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); -int dm_table_get_mode(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); /* @@ -246,15 +459,148 @@ struct mapped_device *dm_table_get_md(struct dm_table *t); 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_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_sector_div64(x, y)( \ +{ \ + u64 _res; \ + (x) = div64_u64_rem(x, y, &_res); \ + _res; \ +} \ +) + +/* + * Ceiling(n / sz) */ -int dm_swap_table(struct mapped_device *md, struct dm_table *t); +#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; \ +} \ +) /* - * Prepare a table for a device that will error all I/O. - * To make it active, call dm_suspend(), dm_swap_table() then dm_resume(). + * ceiling(n / size) * size */ -int dm_create_error_table(struct dm_table **result, struct mapped_device *md); +#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); +} + +/*----------------------------------------------------------------- + * Helper for block layer and dm core operations + *---------------------------------------------------------------*/ +void dm_dispatch_request(struct request *rq); +void dm_requeue_unmapped_request(struct request *rq); +void dm_kill_unmapped_request(struct request *rq, int error); +int dm_underlying_device_busy(struct request_queue *q); -#endif /* __KERNEL__ */ #endif /* _LINUX_DEVICE_MAPPER_H */ |