91212507f9
Make sure dm honours max_hw_sectors of underlying devices We still have no firm testing evidence in support of this patch but believe it may help to resolve some bug reports. - agk Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
261 lines
6.9 KiB
C
261 lines
6.9 KiB
C
/*
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* Copyright (C) 2001 Sistina Software (UK) Limited.
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* Copyright (C) 2004 Red Hat, Inc. All rights reserved.
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*
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* This file is released under the LGPL.
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*/
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#ifndef _LINUX_DEVICE_MAPPER_H
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#define _LINUX_DEVICE_MAPPER_H
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#ifdef __KERNEL__
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struct dm_target;
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struct dm_table;
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struct dm_dev;
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struct mapped_device;
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typedef enum { STATUSTYPE_INFO, STATUSTYPE_TABLE } status_type_t;
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union map_info {
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void *ptr;
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unsigned long long ll;
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};
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/*
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* In the constructor the target parameter will already have the
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* table, type, begin and len fields filled in.
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*/
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typedef int (*dm_ctr_fn) (struct dm_target *target,
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unsigned int argc, char **argv);
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/*
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* The destructor doesn't need to free the dm_target, just
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* anything hidden ti->private.
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*/
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typedef void (*dm_dtr_fn) (struct dm_target *ti);
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/*
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* The map function must return:
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* < 0: error
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* = 0: The target will handle the io by resubmitting it later
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* = 1: simple remap complete
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* = 2: The target wants to push back the io
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*/
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typedef int (*dm_map_fn) (struct dm_target *ti, struct bio *bio,
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union map_info *map_context);
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/*
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* Returns:
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* < 0 : error (currently ignored)
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* 0 : ended successfully
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* 1 : for some reason the io has still not completed (eg,
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* multipath target might want to requeue a failed io).
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* 2 : The target wants to push back the io
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*/
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typedef int (*dm_endio_fn) (struct dm_target *ti,
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struct bio *bio, int error,
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union map_info *map_context);
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typedef void (*dm_flush_fn) (struct dm_target *ti);
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typedef void (*dm_presuspend_fn) (struct dm_target *ti);
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typedef void (*dm_postsuspend_fn) (struct dm_target *ti);
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typedef int (*dm_preresume_fn) (struct dm_target *ti);
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typedef void (*dm_resume_fn) (struct dm_target *ti);
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typedef int (*dm_status_fn) (struct dm_target *ti, status_type_t status_type,
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char *result, unsigned int maxlen);
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typedef int (*dm_message_fn) (struct dm_target *ti, unsigned argc, char **argv);
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typedef int (*dm_ioctl_fn) (struct dm_target *ti, struct inode *inode,
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struct file *filp, unsigned int cmd,
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unsigned long arg);
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void dm_error(const char *message);
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/*
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* Combine device limits.
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*/
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void dm_set_device_limits(struct dm_target *ti, struct block_device *bdev);
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/*
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* Constructors should call these functions to ensure destination devices
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* are opened/closed correctly.
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* FIXME: too many arguments.
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*/
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int dm_get_device(struct dm_target *ti, const char *path, sector_t start,
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sector_t len, int mode, struct dm_dev **result);
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void dm_put_device(struct dm_target *ti, struct dm_dev *d);
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/*
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* Information about a target type
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*/
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struct target_type {
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const char *name;
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struct module *module;
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unsigned version[3];
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dm_ctr_fn ctr;
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dm_dtr_fn dtr;
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dm_map_fn map;
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dm_endio_fn end_io;
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dm_flush_fn flush;
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dm_presuspend_fn presuspend;
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dm_postsuspend_fn postsuspend;
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dm_preresume_fn preresume;
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dm_resume_fn resume;
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dm_status_fn status;
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dm_message_fn message;
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dm_ioctl_fn ioctl;
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};
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struct io_restrictions {
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unsigned int max_sectors;
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unsigned short max_phys_segments;
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unsigned short max_hw_segments;
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unsigned short hardsect_size;
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unsigned int max_segment_size;
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unsigned int max_hw_sectors;
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unsigned long seg_boundary_mask;
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unsigned long bounce_pfn;
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unsigned char no_cluster; /* inverted so that 0 is default */
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};
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struct dm_target {
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struct dm_table *table;
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struct target_type *type;
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/* target limits */
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sector_t begin;
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sector_t len;
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/* FIXME: turn this into a mask, and merge with io_restrictions */
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/* Always a power of 2 */
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sector_t split_io;
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/*
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* These are automatically filled in by
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* dm_table_get_device.
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*/
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struct io_restrictions limits;
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/* target specific data */
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void *private;
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/* Used to provide an error string from the ctr */
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char *error;
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};
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int dm_register_target(struct target_type *t);
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int dm_unregister_target(struct target_type *t);
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/*-----------------------------------------------------------------
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* Functions for creating and manipulating mapped devices.
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* Drop the reference with dm_put when you finish with the object.
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*---------------------------------------------------------------*/
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/*
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* DM_ANY_MINOR chooses the next available minor number.
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*/
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#define DM_ANY_MINOR (-1)
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int dm_create(int minor, struct mapped_device **md);
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/*
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* Reference counting for md.
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*/
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struct mapped_device *dm_get_md(dev_t dev);
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void dm_get(struct mapped_device *md);
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void dm_put(struct mapped_device *md);
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/*
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* An arbitrary pointer may be stored alongside a mapped device.
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*/
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void dm_set_mdptr(struct mapped_device *md, void *ptr);
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void *dm_get_mdptr(struct mapped_device *md);
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/*
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* A device can still be used while suspended, but I/O is deferred.
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*/
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int dm_suspend(struct mapped_device *md, unsigned suspend_flags);
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int dm_resume(struct mapped_device *md);
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/*
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* Event functions.
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*/
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uint32_t dm_get_event_nr(struct mapped_device *md);
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int dm_wait_event(struct mapped_device *md, int event_nr);
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uint32_t dm_next_uevent_seq(struct mapped_device *md);
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void dm_uevent_add(struct mapped_device *md, struct list_head *elist);
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/*
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* Info functions.
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*/
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const char *dm_device_name(struct mapped_device *md);
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int dm_copy_name_and_uuid(struct mapped_device *md, char *name, char *uuid);
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struct gendisk *dm_disk(struct mapped_device *md);
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int dm_suspended(struct mapped_device *md);
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int dm_noflush_suspending(struct dm_target *ti);
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/*
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* Geometry functions.
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*/
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int dm_get_geometry(struct mapped_device *md, struct hd_geometry *geo);
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int dm_set_geometry(struct mapped_device *md, struct hd_geometry *geo);
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/*-----------------------------------------------------------------
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* Functions for manipulating device-mapper tables.
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*---------------------------------------------------------------*/
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/*
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* First create an empty table.
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*/
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int dm_table_create(struct dm_table **result, int mode,
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unsigned num_targets, struct mapped_device *md);
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/*
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* Then call this once for each target.
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*/
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int dm_table_add_target(struct dm_table *t, const char *type,
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sector_t start, sector_t len, char *params);
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/*
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* Finally call this to make the table ready for use.
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*/
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int dm_table_complete(struct dm_table *t);
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/*
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* Table reference counting.
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*/
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struct dm_table *dm_get_table(struct mapped_device *md);
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void dm_table_get(struct dm_table *t);
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void dm_table_put(struct dm_table *t);
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/*
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* Queries
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*/
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sector_t dm_table_get_size(struct dm_table *t);
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unsigned int dm_table_get_num_targets(struct dm_table *t);
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int dm_table_get_mode(struct dm_table *t);
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struct mapped_device *dm_table_get_md(struct dm_table *t);
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/*
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* Trigger an event.
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*/
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void dm_table_event(struct dm_table *t);
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/*
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* The device must be suspended before calling this method.
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*/
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int dm_swap_table(struct mapped_device *md, struct dm_table *t);
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/*
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* Prepare a table for a device that will error all I/O.
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* To make it active, call dm_suspend(), dm_swap_table() then dm_resume().
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*/
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int dm_create_error_table(struct dm_table **result, struct mapped_device *md);
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#endif /* __KERNEL__ */
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#endif /* _LINUX_DEVICE_MAPPER_H */
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