external/gpl2/lvm2/dist/libdm/misc/dm-log-userspace.h

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