linux/include/linux/dm-log-userspace.h
<<
>>
Prefs
   1/*
   2 * Copyright (C) 2006-2009 Red Hat, Inc.
   3 *
   4 * This file is released under the LGPL.
   5 */
   6
   7#ifndef __DM_LOG_USERSPACE_H__
   8#define __DM_LOG_USERSPACE_H__
   9
  10#include <linux/dm-ioctl.h> /* For DM_UUID_LEN */
  11
  12/*
  13 * The device-mapper userspace log module consists of a kernel component and
  14 * a user-space component.  The kernel component implements the API defined
  15 * in dm-dirty-log.h.  Its purpose is simply to pass the parameters and
  16 * return values of those API functions between kernel and user-space.
  17 *
  18 * Below are defined the 'request_types' - DM_ULOG_CTR, DM_ULOG_DTR, etc.
  19 * These request types represent the different functions in the device-mapper
  20 * dirty log API.  Each of these is described in more detail below.
  21 *
  22 * The user-space program must listen for requests from the kernel (representing
  23 * the various API functions) and process them.
  24 *
  25 * User-space begins by setting up the communication link (error checking
  26 * removed for clarity):
  27 *      fd = socket(PF_NETLINK, SOCK_DGRAM, NETLINK_CONNECTOR);
  28 *      addr.nl_family = AF_NETLINK;
  29 *      addr.nl_groups = CN_IDX_DM;
  30 *      addr.nl_pid = 0;
  31 *      r = bind(fd, (struct sockaddr *) &addr, sizeof(addr));
  32 *      opt = addr.nl_groups;
  33 *      setsockopt(fd, SOL_NETLINK, NETLINK_ADD_MEMBERSHIP, &opt, sizeof(opt));
  34 *
  35 * User-space will then wait to receive requests form the kernel, which it
  36 * will process as described below.  The requests are received in the form,
  37 * ((struct dm_ulog_request) + (additional data)).  Depending on the request
  38 * type, there may or may not be 'additional data'.  In the descriptions below,
  39 * you will see 'Payload-to-userspace' and 'Payload-to-kernel'.  The
  40 * 'Payload-to-userspace' is what the kernel sends in 'additional data' as
  41 * necessary parameters to complete the request.  The 'Payload-to-kernel' is
  42 * the 'additional data' returned to the kernel that contains the necessary
  43 * results of the request.  The 'data_size' field in the dm_ulog_request
  44 * structure denotes the availability and amount of payload data.
  45 */
  46
  47/*
  48 * DM_ULOG_CTR corresponds to (found in dm-dirty-log.h):
  49 * int (*ctr)(struct dm_dirty_log *log, struct dm_target *ti,
  50 *            unsigned argc, char **argv);
  51 *
  52 * Payload-to-userspace:
  53 *      A single string containing all the argv arguments separated by ' 's
  54 * Payload-to-kernel:
  55 *      None.  ('data_size' in the dm_ulog_request struct should be 0.)
  56 *
  57 * The UUID contained in the dm_ulog_request structure is the reference that
  58 * will be used by all request types to a specific log.  The constructor must
  59 * record this assotiation with instance created.
  60 *
  61 * When the request has been processed, user-space must return the
  62 * dm_ulog_request to the kernel - setting the 'error' field and
  63 * 'data_size' appropriately.
  64 */
  65#define DM_ULOG_CTR                    1
  66
  67/*
  68 * DM_ULOG_DTR corresponds to (found in dm-dirty-log.h):
  69 * void (*dtr)(struct dm_dirty_log *log);
  70 *
  71 * Payload-to-userspace:
  72 *      A single string containing all the argv arguments separated by ' 's
  73 * Payload-to-kernel:
  74 *      None.  ('data_size' in the dm_ulog_request struct should be 0.)
  75 *
  76 * The UUID contained in the dm_ulog_request structure is all that is
  77 * necessary to identify the log instance being destroyed.  There is no
  78 * payload data.
  79 *
  80 * When the request has been processed, user-space must return the
  81 * dm_ulog_request to the kernel - setting the 'error' field and clearing
  82 * 'data_size' appropriately.
  83 */
  84#define DM_ULOG_DTR                    2
  85
  86/*
  87 * DM_ULOG_PRESUSPEND corresponds to (found in dm-dirty-log.h):
  88 * int (*presuspend)(struct dm_dirty_log *log);
  89 *
  90 * Payload-to-userspace:
  91 *      None.
  92 * Payload-to-kernel:
  93 *      None.
  94 *
  95 * The UUID contained in the dm_ulog_request structure is all that is
  96 * necessary to identify the log instance being presuspended.  There is no
  97 * payload data.
  98 *
  99 * When the request has been processed, user-space must return the
 100 * dm_ulog_request to the kernel - setting the 'error' field and
 101 * 'data_size' appropriately.
 102 */
 103#define DM_ULOG_PRESUSPEND             3
 104
 105/*
 106 * DM_ULOG_POSTSUSPEND corresponds to (found in dm-dirty-log.h):
 107 * int (*postsuspend)(struct dm_dirty_log *log);
 108 *
 109 * Payload-to-userspace:
 110 *      None.
 111 * Payload-to-kernel:
 112 *      None.
 113 *
 114 * The UUID contained in the dm_ulog_request structure is all that is
 115 * necessary to identify the log instance being postsuspended.  There is no
 116 * payload data.
 117 *
 118 * When the request has been processed, user-space must return the
 119 * dm_ulog_request to the kernel - setting the 'error' field and
 120 * 'data_size' appropriately.
 121 */
 122#define DM_ULOG_POSTSUSPEND            4
 123
 124/*
 125 * DM_ULOG_RESUME corresponds to (found in dm-dirty-log.h):
 126 * int (*resume)(struct dm_dirty_log *log);
 127 *
 128 * Payload-to-userspace:
 129 *      None.
 130 * Payload-to-kernel:
 131 *      None.
 132 *
 133 * The UUID contained in the dm_ulog_request structure is all that is
 134 * necessary to identify the log instance being resumed.  There is no
 135 * payload data.
 136 *
 137 * When the request has been processed, user-space must return the
 138 * dm_ulog_request to the kernel - setting the 'error' field and
 139 * 'data_size' appropriately.
 140 */
 141#define DM_ULOG_RESUME                 5
 142
 143/*
 144 * DM_ULOG_GET_REGION_SIZE corresponds to (found in dm-dirty-log.h):
 145 * uint32_t (*get_region_size)(struct dm_dirty_log *log);
 146 *
 147 * Payload-to-userspace:
 148 *      None.
 149 * Payload-to-kernel:
 150 *      uint64_t - contains the region size
 151 *
 152 * The region size is something that was determined at constructor time.
 153 * It is returned in the payload area and 'data_size' is set to
 154 * reflect this.
 155 *
 156 * When the request has been processed, user-space must return the
 157 * dm_ulog_request to the kernel - setting the 'error' field appropriately.
 158 */
 159#define DM_ULOG_GET_REGION_SIZE        6
 160
 161/*
 162 * DM_ULOG_IS_CLEAN corresponds to (found in dm-dirty-log.h):
 163 * int (*is_clean)(struct dm_dirty_log *log, region_t region);
 164 *
 165 * Payload-to-userspace:
 166 *      uint64_t - the region to get clean status on
 167 * Payload-to-kernel:
 168 *      int64_t  - 1 if clean, 0 otherwise
 169 *
 170 * Payload is sizeof(uint64_t) and contains the region for which the clean
 171 * status is being made.
 172 *
 173 * When the request has been processed, user-space must return the
 174 * dm_ulog_request to the kernel - filling the payload with 0 (not clean) or
 175 * 1 (clean), setting 'data_size' and 'error' appropriately.
 176 */
 177#define DM_ULOG_IS_CLEAN               7
 178
 179/*
 180 * DM_ULOG_IN_SYNC corresponds to (found in dm-dirty-log.h):
 181 * int (*in_sync)(struct dm_dirty_log *log, region_t region,
 182 *                int can_block);
 183 *
 184 * Payload-to-userspace:
 185 *      uint64_t - the region to get sync status on
 186 * Payload-to-kernel:
 187 *      int64_t - 1 if in-sync, 0 otherwise
 188 *
 189 * Exactly the same as 'is_clean' above, except this time asking "has the
 190 * region been recovered?" vs. "is the region not being modified?"
 191 */
 192#define DM_ULOG_IN_SYNC                8
 193
 194/*
 195 * DM_ULOG_FLUSH corresponds to (found in dm-dirty-log.h):
 196 * int (*flush)(struct dm_dirty_log *log);
 197 *
 198 * Payload-to-userspace:
 199 *      None.
 200 * Payload-to-kernel:
 201 *      None.
 202 *
 203 * No incoming or outgoing payload.  Simply flush log state to disk.
 204 *
 205 * When the request has been processed, user-space must return the
 206 * dm_ulog_request to the kernel - setting the 'error' field and clearing
 207 * 'data_size' appropriately.
 208 */
 209#define DM_ULOG_FLUSH                  9
 210
 211/*
 212 * DM_ULOG_MARK_REGION corresponds to (found in dm-dirty-log.h):
 213 * void (*mark_region)(struct dm_dirty_log *log, region_t region);
 214 *
 215 * Payload-to-userspace:
 216 *      uint64_t [] - region(s) to mark
 217 * Payload-to-kernel:
 218 *      None.
 219 *
 220 * Incoming payload contains the one or more regions to mark dirty.
 221 * The number of regions contained in the payload can be determined from
 222 * 'data_size/sizeof(uint64_t)'.
 223 *
 224 * When the request has been processed, user-space must return the
 225 * dm_ulog_request to the kernel - setting the 'error' field and clearing
 226 * 'data_size' appropriately.
 227 */
 228#define DM_ULOG_MARK_REGION           10
 229
 230/*
 231 * DM_ULOG_CLEAR_REGION corresponds to (found in dm-dirty-log.h):
 232 * void (*clear_region)(struct dm_dirty_log *log, region_t region);
 233 *
 234 * Payload-to-userspace:
 235 *      uint64_t [] - region(s) to clear
 236 * Payload-to-kernel:
 237 *      None.
 238 *
 239 * Incoming payload contains the one or more regions to mark clean.
 240 * The number of regions contained in the payload can be determined from
 241 * 'data_size/sizeof(uint64_t)'.
 242 *
 243 * When the request has been processed, user-space must return the
 244 * dm_ulog_request to the kernel - setting the 'error' field and clearing
 245 * 'data_size' appropriately.
 246 */
 247#define DM_ULOG_CLEAR_REGION          11
 248
 249/*
 250 * DM_ULOG_GET_RESYNC_WORK corresponds to (found in dm-dirty-log.h):
 251 * int (*get_resync_work)(struct dm_dirty_log *log, region_t *region);
 252 *
 253 * Payload-to-userspace:
 254 *      None.
 255 * Payload-to-kernel:
 256 *      {
 257 *              int64_t i; -- 1 if recovery necessary, 0 otherwise
 258 *              uint64_t r; -- The region to recover if i=1
 259 *      }
 260 * 'data_size' should be set appropriately.
 261 *
 262 * When the request has been processed, user-space must return the
 263 * dm_ulog_request to the kernel - setting the 'error' field appropriately.
 264 */
 265#define DM_ULOG_GET_RESYNC_WORK       12
 266
 267/*
 268 * DM_ULOG_SET_REGION_SYNC corresponds to (found in dm-dirty-log.h):
 269 * void (*set_region_sync)(struct dm_dirty_log *log,
 270 *                         region_t region, int in_sync);
 271 *
 272 * Payload-to-userspace:
 273 *      {
 274 *              uint64_t - region to set sync state on
 275 *              int64_t  - 0 if not-in-sync, 1 if in-sync
 276 *      }
 277 * Payload-to-kernel:
 278 *      None.
 279 *
 280 * When the request has been processed, user-space must return the
 281 * dm_ulog_request to the kernel - setting the 'error' field and clearing
 282 * 'data_size' appropriately.
 283 */
 284#define DM_ULOG_SET_REGION_SYNC       13
 285
 286/*
 287 * DM_ULOG_GET_SYNC_COUNT corresponds to (found in dm-dirty-log.h):
 288 * region_t (*get_sync_count)(struct dm_dirty_log *log);
 289 *
 290 * Payload-to-userspace:
 291 *      None.
 292 * Payload-to-kernel:
 293 *      uint64_t - the number of in-sync regions
 294 *
 295 * No incoming payload.  Kernel-bound payload contains the number of
 296 * regions that are in-sync (in a size_t).
 297 *
 298 * When the request has been processed, user-space must return the
 299 * dm_ulog_request to the kernel - setting the 'error' field and
 300 * 'data_size' appropriately.
 301 */
 302#define DM_ULOG_GET_SYNC_COUNT        14
 303
 304/*
 305 * DM_ULOG_STATUS_INFO corresponds to (found in dm-dirty-log.h):
 306 * int (*status)(struct dm_dirty_log *log, STATUSTYPE_INFO,
 307 *               char *result, unsigned maxlen);
 308 *
 309 * Payload-to-userspace:
 310 *      None.
 311 * Payload-to-kernel:
 312 *      Character string containing STATUSTYPE_INFO
 313 *
 314 * When the request has been processed, user-space must return the
 315 * dm_ulog_request to the kernel - setting the 'error' field and
 316 * 'data_size' appropriately.
 317 */
 318#define DM_ULOG_STATUS_INFO           15
 319
 320/*
 321 * DM_ULOG_STATUS_TABLE corresponds to (found in dm-dirty-log.h):
 322 * int (*status)(struct dm_dirty_log *log, STATUSTYPE_TABLE,
 323 *               char *result, unsigned maxlen);
 324 *
 325 * Payload-to-userspace:
 326 *      None.
 327 * Payload-to-kernel:
 328 *      Character string containing STATUSTYPE_TABLE
 329 *
 330 * When the request has been processed, user-space must return the
 331 * dm_ulog_request to the kernel - setting the 'error' field and
 332 * 'data_size' appropriately.
 333 */
 334#define DM_ULOG_STATUS_TABLE          16
 335
 336/*
 337 * DM_ULOG_IS_REMOTE_RECOVERING corresponds to (found in dm-dirty-log.h):
 338 * int (*is_remote_recovering)(struct dm_dirty_log *log, region_t region);
 339 *
 340 * Payload-to-userspace:
 341 *      uint64_t - region to determine recovery status on
 342 * Payload-to-kernel:
 343 *      {
 344 *              int64_t is_recovering;  -- 0 if no, 1 if yes
 345 *              uint64_t in_sync_hint;  -- lowest region still needing resync
 346 *      }
 347 *
 348 * When the request has been processed, user-space must return the
 349 * dm_ulog_request to the kernel - setting the 'error' field and
 350 * 'data_size' appropriately.
 351 */
 352#define DM_ULOG_IS_REMOTE_RECOVERING  17
 353
 354/*
 355 * (DM_ULOG_REQUEST_MASK & request_type) to get the request type
 356 *
 357 * Payload-to-userspace:
 358 *      A single string containing all the argv arguments separated by ' 's
 359 * Payload-to-kernel:
 360 *      None.  ('data_size' in the dm_ulog_request struct should be 0.)
 361 *
 362 * We are reserving 8 bits of the 32-bit 'request_type' field for the
 363 * various request types above.  The remaining 24-bits are currently
 364 * set to zero and are reserved for future use and compatibility concerns.
 365 *
 366 * User-space should always use DM_ULOG_REQUEST_TYPE to acquire the
 367 * request type from the 'request_type' field to maintain forward compatibility.
 368 */
 369#define DM_ULOG_REQUEST_MASK 0xFF
 370#define DM_ULOG_REQUEST_TYPE(request_type) \
 371        (DM_ULOG_REQUEST_MASK & (request_type))
 372
 373struct dm_ulog_request {
 374        /*
 375         * The local unique identifier (luid) and the universally unique
 376         * identifier (uuid) are used to tie a request to a specific
 377         * mirror log.  A single machine log could probably make due with
 378         * just the 'luid', but a cluster-aware log must use the 'uuid' and
 379         * the 'luid'.  The uuid is what is required for node to node
 380         * communication concerning a particular log, but the 'luid' helps
 381         * differentiate between logs that are being swapped and have the
 382         * same 'uuid'.  (Think "live" and "inactive" device-mapper tables.)
 383         */
 384        uint64_t luid;
 385        char uuid[DM_UUID_LEN];
 386        char padding[7];        /* Padding because DM_UUID_LEN = 129 */
 387
 388        int32_t error;          /* Used to report back processing errors */
 389
 390        uint32_t seq;           /* Sequence number for request */
 391        uint32_t request_type;  /* DM_ULOG_* defined above */
 392        uint32_t data_size;     /* How much data (not including this struct) */
 393
 394        char data[0];
 395};
 396
 397#endif /* __DM_LOG_USERSPACE_H__ */
 398
lxr.linux.no kindly hosted by Redpill Linpro AS, provider of Linux consulting and operations services since 1995.