drivers/md/dm.h

   1 /*
   2  * Internal header file for device mapper
   3  *
   4  * Copyright (C) 2001, 2002 Sistina Software
   5  * Copyright (C) 2004-2006 Red Hat, Inc. All rights reserved.
   6  *
   7  * This file is released under the LGPL.
   8  */
   9
  10 #ifndef DM_INTERNAL_H
  11 #define DM_INTERNAL_H
  12
  13 #include <linux/fs.h>
  14 #include <linux/device-mapper.h>
  15 #include <linux/list.h>
  16 #include <linux/blkdev.h>
  17 #include <linux/hdreg.h>
  18
  19 #include "dm-stats.h"
  20
  21 /*
  22  * Suspend feature flags
  23  */
  24 #define DM_SUSPEND_LOCKFS_FLAG          (1 << 0)
  25 #define DM_SUSPEND_NOFLUSH_FLAG         (1 << 1)
  26
  27 /*
  28  * Status feature flags
  29  */
  30 #define DM_STATUS_NOFLUSH_FLAG          (1 << 0)
  31
  32 /*
  33  * Type of table and mapped_device's mempool
  34  */
  35 #define DM_TYPE_NONE            0
  36 #define DM_TYPE_BIO_BASED       1
  37 #define DM_TYPE_REQUEST_BASED   2
  38
  39 /*
  40  * List of devices that a metadevice uses and should open/close.
  41  */
  42 struct dm_dev_internal {
  43         struct list_head list;
  44         atomic_t count;
  45         struct dm_dev dm_dev;
  46 };
  47
  48 struct dm_table;
  49 struct dm_md_mempools;
  50
  51 /*-----------------------------------------------------------------
  52  * Internal table functions.
  53  *---------------------------------------------------------------*/
  54 void dm_table_destroy(struct dm_table *t);
  55 void dm_table_event_callback(struct dm_table *t,
  56                              void (*fn)(void *), void *context);
  57 struct dm_target *dm_table_get_target(struct dm_table *t, unsigned int index);
  58 struct dm_target *dm_table_find_target(struct dm_table *t, sector_t sector);
  59 bool dm_table_has_no_data_devices(struct dm_table *table);
  60 int dm_calculate_queue_limits(struct dm_table *table,
  61                               struct queue_limits *limits);
  62 void dm_table_set_restrictions(struct dm_table *t, struct request_queue *q,
  63                                struct queue_limits *limits);
  64 struct list_head *dm_table_get_devices(struct dm_table *t);
  65 void dm_table_presuspend_targets(struct dm_table *t);
  66 void dm_table_postsuspend_targets(struct dm_table *t);
  67 int dm_table_resume_targets(struct dm_table *t);
  68 int dm_table_any_congested(struct dm_table *t, int bdi_bits);
  69 int dm_table_any_busy_target(struct dm_table *t);
  70 unsigned dm_table_get_type(struct dm_table *t);
  71 struct target_type *dm_table_get_immutable_target_type(struct dm_table *t);
  72 bool dm_table_request_based(struct dm_table *t);
  73 bool dm_table_supports_discards(struct dm_table *t);
  74 int dm_table_alloc_md_mempools(struct dm_table *t);
  75 void dm_table_free_md_mempools(struct dm_table *t);
  76 struct dm_md_mempools *dm_table_get_md_mempools(struct dm_table *t);
  77
  78 int dm_queue_merge_is_compulsory(struct request_queue *q);
  79
  80 void dm_lock_md_type(struct mapped_device *md);
  81 void dm_unlock_md_type(struct mapped_device *md);
  82 void dm_set_md_type(struct mapped_device *md, unsigned type);
  83 unsigned dm_get_md_type(struct mapped_device *md);
  84 struct target_type *dm_get_immutable_target_type(struct mapped_device *md);
  85
  86 int dm_setup_md_queue(struct mapped_device *md);
  87
  88 /*
  89  * To check the return value from dm_table_find_target().
  90  */
  91 #define dm_target_is_valid(t) ((t)->table)
  92
  93 /*
  94  * To check whether the target type is bio-based or not (request-based).
  95  */
  96 #define dm_target_bio_based(t) ((t)->type->map != NULL)
  97
  98 /*
  99  * To check whether the target type is request-based or not (bio-based).
 100  */
 101 #define dm_target_request_based(t) ((t)->type->map_rq != NULL)
 102
 103 /*
 104  * To check whether the target type is a hybrid (capable of being
 105  * either request-based or bio-based).
 106  */
 107 #define dm_target_hybrid(t) (dm_target_bio_based(t) && dm_target_request_based(t))
 108
 109 /*-----------------------------------------------------------------
 110  * A registry of target types.
 111  *---------------------------------------------------------------*/
 112 int dm_target_init(void);
 113 void dm_target_exit(void);
 114 struct target_type *dm_get_target_type(const char *name);
 115 void dm_put_target_type(struct target_type *tt);
 116 int dm_target_iterate(void (*iter_func)(struct target_type *tt,
 117                                         void *param), void *param);
 118
 119 int dm_split_args(int *argc, char ***argvp, char *input);
 120
 121 /*
 122  * Is this mapped_device being deleted?
 123  */
 124 int dm_deleting_md(struct mapped_device *md);
 125
 126 /*
 127  * Is this mapped_device suspended?
 128  */
 129 int dm_suspended_md(struct mapped_device *md);
 130
 131 /*
 132  * Test if the device is scheduled for deferred remove.
 133  */
 134 int dm_test_deferred_remove_flag(struct mapped_device *md);
 135
 136 /*
 137  * Try to remove devices marked for deferred removal.
 138  */
 139 void dm_deferred_remove(void);
 140
 141 /*
 142  * The device-mapper can be driven through one of two interfaces;
 143  * ioctl or filesystem, depending which patch you have applied.
 144  */
 145 int dm_interface_init(void);
 146 void dm_interface_exit(void);
 147
 148 /*
 149  * sysfs interface
 150  */
 151 int dm_sysfs_init(struct mapped_device *md);
 152 void dm_sysfs_exit(struct mapped_device *md);
 153 struct kobject *dm_kobject(struct mapped_device *md);
 154 struct mapped_device *dm_get_from_kobject(struct kobject *kobj);
 155
 156 /*
 157  * Targets for linear and striped mappings
 158  */
 159 int dm_linear_init(void);
 160 void dm_linear_exit(void);
 161
 162 int dm_stripe_init(void);
 163 void dm_stripe_exit(void);
 164
 165 /*
 166  * mapped_device operations
 167  */
 168 void dm_destroy(struct mapped_device *md);
 169 void dm_destroy_immediate(struct mapped_device *md);
 170 int dm_open_count(struct mapped_device *md);
 171 int dm_lock_for_deletion(struct mapped_device *md, bool mark_deferred, bool only_deferred);
 172 int dm_cancel_deferred_remove(struct mapped_device *md);
 173 int dm_request_based(struct mapped_device *md);
 174 sector_t dm_get_size(struct mapped_device *md);
 175 struct dm_stats *dm_get_stats(struct mapped_device *md);
 176
 177 int dm_kobject_uevent(struct mapped_device *md, enum kobject_action action,
 178                       unsigned cookie);
 179
 180 void dm_internal_suspend(struct mapped_device *md);
 181 void dm_internal_resume(struct mapped_device *md);
 182
 183 int dm_io_init(void);
 184 void dm_io_exit(void);
 185
 186 int dm_kcopyd_init(void);
 187 void dm_kcopyd_exit(void);
 188
 189 /*
 190  * Mempool operations
 191  */
 192 struct dm_md_mempools *dm_alloc_md_mempools(unsigned type, unsigned integrity, unsigned per_bio_data_size);
 193 void dm_free_md_mempools(struct dm_md_mempools *pools);
 194
 195 /*
 196  * Helpers that are used by DM core
 197  */
 198 unsigned dm_get_reserved_bio_based_ios(void);
 199 unsigned dm_get_reserved_rq_based_ios(void);
 200
 201 static inline bool dm_message_test_buffer_overflow(char *result, unsigned maxlen)
 202 {
 203         return !maxlen || strlen(result) + 1 >= maxlen;
 204 }
 205
 206 #endif