design.txt revision 1.2.8.2
1 1.2.8.2 yamt Device-mapper to libdevmapper protocol 2 1.2.8.2 yamt 3 1.2.8.2 yamt 4 1.2.8.2 yamt 5 1.2.8.2 yamt 1) Device mapper device in a POV of LVM it is an Logical Volume. 6 1.2.8.2 yamt Logical Volume is virtual block device is made from logical blocks. 7 1.2.8.2 yamt These blocks are mapped to real device blocks with algorithm called 8 1.2.8.2 yamt target. 9 1.2.8.2 yamt 10 1.2.8.2 yamt Functions available to dm device: 11 1.2.8.2 yamt create, remove, list, status of device. 12 1.2.8.2 yamt 13 1.2.8.2 yamt 2) device mapper target is function which defines how are Logical blocks 14 1.2.8.2 yamt mapped to physical. There are many targets linear, stripe, mirror etc. 15 1.2.8.2 yamt 16 1.2.8.2 yamt Functions available to dm device: 17 1.2.8.2 yamt list available targets. They can be added with module in linux. 18 1.2.8.2 yamt 19 1.2.8.2 yamt 3) dm table. 20 1.2.8.2 yamt Every device-mapper device consits from one or more tables. Table specify 21 1.2.8.2 yamt Start, length of logical blocks and target which is used to map them to 22 1.2.8.2 yamt physical blocks. 23 1.2.8.2 yamt 24 1.2.8.2 yamt {start} {length} {target} | {device} {target parameters} 25 1.2.8.2 yamt 26 1.2.8.2 yamt after | are target specific parameters listed. 27 1.2.8.2 yamt 28 1.2.8.2 yamt Functions available to dm device: 29 1.2.8.2 yamt load, unload, table_status. 30 1.2.8.2 yamt 31 1.2.8.2 yamt 32 1.2.8.2 yamt List of available ioct calls 33 1.2.8.2 yamt 34 1.2.8.2 yamt DM_VERSION 35 1.2.8.2 yamt DM_REMOVE_ALL 36 1.2.8.2 yamt DM_LIST_DEVICES 37 1.2.8.2 yamt DM_DEV_CREATE 38 1.2.8.2 yamt DM_DEV_REMOVE 39 1.2.8.2 yamt DM_DEV_RENAME 40 1.2.8.2 yamt DM_DEV_SUSPEND 41 1.2.8.2 yamt DM_DEV_STATUS 42 1.2.8.2 yamt DM_DEV_WAIT 43 1.2.8.2 yamt DM_TABLE_LOAD 44 1.2.8.2 yamt DM_TABLE_CLEAR 45 1.2.8.2 yamt DM_TABLE_DEPS 46 1.2.8.2 yamt DM_TABLE_STATUS 47 1.2.8.2 yamt DM_LIST_VERSIONS 48 1.2.8.2 yamt DM_TARGET_MSG 49 1.2.8.2 yamt DM_DEV_SET_GEOMETRY 50 1.2.8.2 yamt 51 1.2.8.2 yamt 1) DM_VERSION 52 1.2.8.2 yamt 53 1.2.8.2 yamt in: struct dm-ioctl 54 1.2.8.2 yamt 55 1.2.8.2 yamt out: struct dm-ioctl 56 1.2.8.2 yamt 57 1.2.8.2 yamt Fuction: 58 1.2.8.2 yamt sends libdevmapper ioctl protocol version to kernel and ask for kernel version. 59 1.2.8.2 yamt If major and minor numbers are good we can continue. 60 1.2.8.2 yamt 61 1.2.8.2 yamt 2) DM_REMOVE_ALL 62 1.2.8.2 yamt 63 1.2.8.2 yamt in: none 64 1.2.8.2 yamt 65 1.2.8.2 yamt out: none 66 1.2.8.2 yamt 67 1.2.8.2 yamt Function: 68 1.2.8.2 yamt This ioctl will remove all DM devices/tables from DM driver. 69 1.2.8.2 yamt 70 1.2.8.2 yamt 3) DM_LIST_DEVICES 71 1.2.8.2 yamt 72 1.2.8.2 yamt in: none 73 1.2.8.2 yamt 74 1.2.8.2 yamt out: List of structures describing all devices created in driver. 75 1.2.8.2 yamt 76 1.2.8.2 yamt Function: 77 1.2.8.2 yamt List all devices created in driver. (linux use struct dm_name_list) 78 1.2.8.2 yamt 79 1.2.8.2 yamt Implementation: 80 1.2.8.2 yamt Kernel driver will place list of struct dm_name_list behind 81 1.2.8.2 yamt struct dm_ioctl in userspace. Kernel driver will list through 82 1.2.8.2 yamt the all devices and copyout info about them. 83 1.2.8.2 yamt 84 1.2.8.2 yamt 4) DM_DEV_CREATE 85 1.2.8.2 yamt 86 1.2.8.2 yamt in: struct dm-ioctl(name/uuid) 87 1.2.8.2 yamt 88 1.2.8.2 yamt out: none 89 1.2.8.2 yamt 90 1.2.8.2 yamt Function: 91 1.2.8.2 yamt Create device in dm driver, with specified name/uuid(uuid is prefered). 92 1.2.8.2 yamt (linux use struct dm_name_list) 93 1.2.8.2 yamt 94 1.2.8.2 yamt 5) DM_DEV_REMOVE 95 1.2.8.2 yamt 96 1.2.8.2 yamt in: struct dm-ioctl(name/uuid) 97 1.2.8.2 yamt 98 1.2.8.2 yamt out: none 99 1.2.8.2 yamt 100 1.2.8.2 yamt Function: 101 1.2.8.2 yamt Remove device from dm driver list, also remove device tables. 102 1.2.8.2 yamt 103 1.2.8.2 yamt 6) DM_DEV_RENAME 104 1.2.8.2 yamt 105 1.2.8.2 yamt in: struct dm-ioctl(name/uuid) and string found after dm-ioctl struct in buffer 106 1.2.8.2 yamt 107 1.2.8.2 yamt out: none 108 1.2.8.2 yamt 109 1.2.8.2 yamt Function: 110 1.2.8.2 yamt Rename device from name to string. 111 1.2.8.2 yamt 112 1.2.8.2 yamt Implementation: 113 1.2.8.2 yamt Kernel driver will find device with name from struct dm_ioctl-name/uuid. 114 1.2.8.2 yamt Change name of selected device to string foun behind struc dm_ioctl header 115 1.2.8.2 yamt in userspace buffer. 116 1.2.8.2 yamt 117 1.2.8.2 yamt 7) DM_DEV_SUSPEND 118 1.2.8.2 yamt 119 1.2.8.2 yamt in: dm-ioctl(name/uuid) 120 1.2.8.2 yamt 121 1.2.8.2 yamt out: none 122 1.2.8.2 yamt 123 1.2.8.2 yamt Function: 124 1.2.8.2 yamt Suspend all io's on device, after this ioctl. Already started io's will be done. 125 1.2.8.2 yamt Newer can't be started. 126 1.2.8.2 yamt 127 1.2.8.2 yamt 8) DM_DEV_STATUS 128 1.2.8.2 yamt 129 1.2.8.2 yamt in: dm-ioctl(name/uuid) 130 1.2.8.2 yamt 131 1.2.8.2 yamt out: dm-ioctl (minor,open_count,target_count) 132 1.2.8.2 yamt 133 1.2.8.2 yamt Function: 134 1.2.8.2 yamt Return status info about selected device 135 1.2.8.2 yamt 136 1.2.8.2 yamt Implementation: 137 1.2.8.2 yamt Kernel driver will find device with name from struct dm_ioctl-name/uuid. 138 1.2.8.2 yamt Change values minor,open_count,target_count in dm_ioctl struct for 139 1.2.8.2 yamt selected device. 140 1.2.8.2 yamt 141 1.2.8.2 yamt 9) DM_DEV_WAIT 142 1.2.8.2 yamt 143 1.2.8.2 yamt in: dm-ioctl(name/uuid) 144 1.2.8.2 yamt 145 1.2.8.2 yamt out: none 146 1.2.8.2 yamt 147 1.2.8.2 yamt Function: 148 1.2.8.2 yamt Wait for device event to happen. 149 1.2.8.2 yamt 150 1.2.8.2 yamt 10) DM_TABLE_LOAD 151 1.2.8.2 yamt 152 1.2.8.2 yamt in: dm-ioctl(name/uuid),table specification 153 1.2.8.2 yamt 154 1.2.8.2 yamt out: none 155 1.2.8.2 yamt 156 1.2.8.2 yamt Function: 157 1.2.8.2 yamt Load table to selected device. Table is loaded to unused slot and than switched. 158 1.2.8.2 yamt (linux use struct dm_target_spec) 159 1.2.8.2 yamt 160 1.2.8.2 yamt Implementation: 161 1.2.8.2 yamt Kernel driver will find device with name from struct dm_ioctl-name/uuid. 162 1.2.8.2 yamt Table is added to the inactive slot. Every device can have more than one 163 1.2.8.2 yamt table loaded. Tables are stored in SLIST. This ioctl also open physical 164 1.2.8.2 yamt device spedcified in table and add it to dm_device specific pdev list. 165 1.2.8.2 yamt 166 1.2.8.2 yamt 11) DM_TABLE_CLEAR 167 1.2.8.2 yamt 168 1.2.8.2 yamt in: dm-ioctl(name/uuid) 169 1.2.8.2 yamt 170 1.2.8.2 yamt out: none 171 1.2.8.2 yamt 172 1.2.8.2 yamt Function: 173 1.2.8.2 yamt Remove table from unused slot. 174 1.2.8.2 yamt 175 1.2.8.2 yamt 12) DM_TABLE_DEPS 176 1.2.8.2 yamt 177 1.2.8.2 yamt in: dm-ioctl(name/uuid) 178 1.2.8.2 yamt 179 1.2.8.2 yamt out: list of dependiences devices 180 1.2.8.2 yamt 181 1.2.8.2 yamt Function: 182 1.2.8.2 yamt Return set of device dependiences e.g. mirror device for mirror target etc.. 183 1.2.8.2 yamt 184 1.2.8.2 yamt 13) DM_TABLE_STATUS 185 1.2.8.2 yamt 186 1.2.8.2 yamt in: dm-ioctl(name/uuid) 187 1.2.8.2 yamt 188 1.2.8.2 yamt out: list of used tables from selected devices (linux use struct dm_target_spec) 189 1.2.8.2 yamt 190 1.2.8.2 yamt Function: 191 1.2.8.2 yamt List all tables in active slot in device with name name/uuid. 192 1.2.8.2 yamt 193 1.2.8.2 yamt Implementation: 194 1.2.8.2 yamt Kernel driver will find device with name from struct dm_ioctl-name/uuid. 195 1.2.8.2 yamt DM driver will copyout dm_target_spec structures behidn struct dm_ioctl. 196 1.2.8.2 yamt 197 1.2.8.2 yamt 14) DM_LIST_VERSIONS 198 1.2.8.2 yamt 199 1.2.8.2 yamt in: none 200 1.2.8.2 yamt 201 1.2.8.2 yamt out: list of all targets in device-mapper driver (linux use struct dm_target_versions) 202 1.2.8.2 yamt 203 1.2.8.2 yamt Function: 204 1.2.8.2 yamt List all available targets to libdevmapper. 205 1.2.8.2 yamt 206 1.2.8.2 yamt Implementation: 207 1.2.8.2 yamt Kernel driver will copy out known target versions. 208 1.2.8.2 yamt 209 1.2.8.2 yamt 15) DM_TARGET_MSG 210 1.2.8.2 yamt 211 1.2.8.2 yamt in: message to driver (linux use struct dm_target_msg) 212 1.2.8.2 yamt 213 1.2.8.2 yamt out: none 214 1.2.8.2 yamt 215 1.2.8.2 yamt Function: 216 1.2.8.2 yamt Send message to kernel driver target. 217 1.2.8.2 yamt 218 1.2.8.2 yamt 219 1.2.8.2 yamt 16) DM_DEV_SET_GEOMETRY 220 1.2.8.2 yamt 221 1.2.8.2 yamt Function: 222 1.2.8.2 yamt Set geometry of device-mapper driver. 223 1.2.8.2 yamt 224 1.2.8.2 yamt 225 1.2.8.2 yamt NetBSD device-mapper driver implementation 226 1.2.8.2 yamt 227 1.2.8.2 yamt device-mapper devices -> devs dm_dev.c 228 1.2.8.2 yamt 229 1.2.8.2 yamt This entity is created with DM_DEV_CREATE ioctl, and stores info 230 1.2.8.2 yamt about every device in device mapper driver. It has two slots for 231 1.2.8.2 yamt active and inactive table, list of active physical devices added 232 1.2.8.2 yamt to this device and list of upcalled devices (for targets which use 233 1.2.8.2 yamt more than one physical device e.g. mirror, snapshot etc..). 234 1.2.8.2 yamt 235 1.2.8.2 yamt device-mapper physical devices -> pdevs dm_pdev.c 236 1.2.8.2 yamt 237 1.2.8.2 yamt This structure contains opened device VNODES. Because I physical 238 1.2.8.2 yamt device can be found in more than one table loaded to different 239 1.2.8.2 yamt dm devices. When device is destroyed I decrement all reference 240 1.2.8.2 yamt counters for all added pdevs (I remove pdevs with ref_cnt == 0). 241 1.2.8.2 yamt 242 1.2.8.2 yamt device-mapper tables -> table dm_table.c, dm_ioctl.c 243 1.2.8.2 yamt 244 1.2.8.2 yamt Table describe how is dm device made. What blocks are mapped with 245 1.2.8.2 yamt what target. In our implementation every table contains pointer to 246 1.2.8.2 yamt target specific config data. These config_data are allocated in 247 1.2.8.2 yamt DM_TABLE_LOAD function with target_init routine. Every table 248 1.2.8.2 yamt contains pointer to used target. 249 1.2.8.2 yamt 250 1.2.8.2 yamt device-mapper targets -> target dm_target.c 251 1.2.8.2 yamt 252 1.2.8.2 yamt Target describes mapping of logical blocks to physical. It has 253 1.2.8.2 yamt function pointers to function which does init, strategy, destroy, 254 1.2.8.2 yamt upcall functions. 255 1.2.8.2 yamt 256 1.2.8.2 yamt P.S I want to thank reinod@ for great help and guidance :). 257 1.2.8.2 yamt 258 1.2.8.2 yamt 259 1.2.8.2 yamt 260 1.2.8.2 yamt Desing of new device-mapper ioctl interface 261 1.2.8.2 yamt 262 1.2.8.2 yamt Basic architecture of device-mapper -> libdevmapper ioctl interface is this. 263 1.2.8.2 yamt Libdevmapper allocate buffer with size of data_size. At the start of this buffer 264 1.2.8.2 yamt dm-ioctl structure is placed. any aditional information from/to kernel are placed 265 1.2.8.2 yamt behind end (start of data part is pointed with data_start var.) of dm-ioctl struct. 266 1.2.8.2 yamt 267 1.2.8.2 yamt Kernel driver then after ioctl call have to copyin data from userspace to kernel. 268 1.2.8.2 yamt When kernel driver want to send data back to user space library it must copyout 269 1.2.8.2 yamt data from kernel. 270 1.2.8.2 yamt 271 1.2.8.2 yamt 1) In Linux device-mapper ioctl interface implementation there are these ioctls. 272 1.2.8.2 yamt 273 1.2.8.2 yamt DM_VERSION * 274 1.2.8.2 yamt DM_REMOVE_ALL 275 1.2.8.2 yamt DM_LIST_DEVICES * 276 1.2.8.2 yamt DM_DEV_CREATE * 277 1.2.8.2 yamt DM_DEV_REMOVE * 278 1.2.8.2 yamt DM_DEV_RENAME * 279 1.2.8.2 yamt DM_DEV_SUSPEND 280 1.2.8.2 yamt DM_DEV_STATUS * 281 1.2.8.2 yamt DM_DEV_WAIT 282 1.2.8.2 yamt DM_TABLE_LOAD * 283 1.2.8.2 yamt DM_TABLE_CLEAR * 284 1.2.8.2 yamt DM_TABLE_DEPS 285 1.2.8.2 yamt DM_TABLE_STATUS * 286 1.2.8.2 yamt DM_LIST_VERSIONS * 287 1.2.8.2 yamt DM_TARGET_MSG 288 1.2.8.2 yamt DM_DEV_SET_GEOMETRY 289 1.2.8.2 yamt 290 1.2.8.2 yamt * means implemented in current version of NetBSD device-mapper. 291 1.2.8.2 yamt 292 1.2.8.2 yamt 1a) struct dm_ioctl based ioctl calls 293 1.2.8.2 yamt These ioctl calls communicate only with basic dm_ioctl structure. 294 1.2.8.2 yamt 295 1.2.8.2 yamt DM_VERSION 296 1.2.8.2 yamt DM_DEV_STATUS 297 1.2.8.2 yamt DM_DEV_CREATE 298 1.2.8.2 yamt 299 1.2.8.2 yamt Protocol structure: 300 1.2.8.2 yamt 301 1.2.8.2 yamt struct dm_ioctl { 302 1.2.8.2 yamt uint32_t version[3]; /* device-mapper kernel/userspace version */ 303 1.2.8.2 yamt uint32_t data_size; /* total size of data passed in 304 1.2.8.2 yamt * including this struct */ 305 1.2.8.2 yamt 306 1.2.8.2 yamt uint32_t data_start; /* offset to start of data 307 1.2.8.2 yamt * relative to start of this struct */ 308 1.2.8.2 yamt 309 1.2.8.2 yamt uint32_t target_count; /* in/out */ /* This should be set when DM_TABLE_STATUS is called */ 310 1.2.8.2 yamt int32_t open_count; /* device open count */ 311 1.2.8.2 yamt uint32_t flags; /* information flags */ 312 1.2.8.2 yamt uint32_t event_nr; /* event counters not implemented */ 313 1.2.8.2 yamt uint32_t padding; 314 1.2.8.2 yamt 315 1.2.8.2 yamt uint64_t dev; /* dev_t */ 316 1.2.8.2 yamt 317 1.2.8.2 yamt char name[DM_NAME_LEN]; /* device name */ 318 1.2.8.2 yamt char uuid[DM_UUID_LEN]; /* unique identifier for 319 1.2.8.2 yamt * the block device */ 320 1.2.8.2 yamt 321 1.2.8.2 yamt void *user_space_addr; /*this is needed for netbsd 322 1.2.8.2 yamt because they differently 323 1.2.8.2 yamt implement ioctl syscall*/ 324 1.2.8.2 yamt }; 325 1.2.8.2 yamt 326 1.2.8.2 yamt As SOC task I want to replace this structure with proplib dict. Proplib dict 327 1.2.8.2 yamt basic structure should be: 328 1.2.8.2 yamt 329 1.2.8.2 yamt Note: I don't need data_star, data_size and use_space_addr. They are needed 330 1.2.8.2 yamt for current implementation. 331 1.2.8.2 yamt 332 1.2.8.2 yamt <dict> 333 1.2.8.2 yamt <key>version</key> 334 1.2.8.2 yamt <string>...</string> 335 1.2.8.2 yamt 336 1.2.8.2 yamt <key>target_count</key> 337 1.2.8.2 yamt <integer></integer> 338 1.2.8.2 yamt 339 1.2.8.2 yamt <key>open_count</key> 340 1.2.8.2 yamt <integer></integer> 341 1.2.8.2 yamt 342 1.2.8.2 yamt <key>flags</key> 343 1.2.8.2 yamt <integer></integer> 344 1.2.8.2 yamt 345 1.2.8.2 yamt <key>event_nr</key> 346 1.2.8.2 yamt <integer></integer> 347 1.2.8.2 yamt 348 1.2.8.2 yamt <key>dev</key> 349 1.2.8.2 yamt <integer></integer> 350 1.2.8.2 yamt 351 1.2.8.2 yamt <key>name</key> 352 1.2.8.2 yamt <string>...</string> 353 1.2.8.2 yamt 354 1.2.8.2 yamt <key>uuid</key> 355 1.2.8.2 yamt <string>...</string> 356 1.2.8.2 yamt 357 1.2.8.2 yamt 358 1.2.8.2 yamt <dict> 359 1.2.8.2 yamt <!-- ioctl specific data --> 360 1.2.8.2 yamt </dict> 361 1.2.8.2 yamt </dict> 362 1.2.8.2 yamt 363 1.2.8.2 yamt 1b) DM_LIST_VERSIONS ioctl 364 1.2.8.2 yamt 365 1.2.8.2 yamt This ioctl is used to get list of supported targets from kernel. Target 366 1.2.8.2 yamt define mapping of Logical blocks to physical blocks on real device. 367 1.2.8.2 yamt There are linear, zero, error, mirror, snapshot, multipath etc... targets. 368 1.2.8.2 yamt 369 1.2.8.2 yamt For every target kernel driver should copyout this structure to userspace. 370 1.2.8.2 yamt 371 1.2.8.2 yamt Protocol structure: 372 1.2.8.2 yamt 373 1.2.8.2 yamt struct dm_target_versions { 374 1.2.8.2 yamt uint32_t next; 375 1.2.8.2 yamt uint32_t version[3]; 376 1.2.8.2 yamt 377 1.2.8.2 yamt char name[0]; 378 1.2.8.2 yamt }; 379 1.2.8.2 yamt 380 1.2.8.2 yamt Because I need more then on dm_target_version I will need one major proplib 381 1.2.8.2 yamt dictionary to store children dictionaries with target data. 382 1.2.8.2 yamt 383 1.2.8.2 yamt <dict> 384 1.2.8.2 yamt <dict ID="id"> 385 1.2.8.2 yamt <key>version</key> 386 1.2.8.2 yamt <string>...</string> 387 1.2.8.2 yamt 388 1.2.8.2 yamt <key>name</key> 389 1.2.8.2 yamt <string>...</string> 390 1.2.8.2 yamt </dict> 391 1.2.8.2 yamt </dict> 392 1.2.8.2 yamt 393 1.2.8.2 yamt 2a) DM_LIST_DEVICES 394 1.2.8.2 yamt 395 1.2.8.2 yamt This ioctl is used to list all devices defined in kernel driver. 396 1.2.8.2 yamt 397 1.2.8.2 yamt Protocol structure: 398 1.2.8.2 yamt 399 1.2.8.2 yamt struct dm_name_list { 400 1.2.8.2 yamt uint64_t dev; 401 1.2.8.2 yamt uint32_t next; /* offset to the next record from 402 1.2.8.2 yamt the _start_ of this */ 403 1.2.8.2 yamt char name[0]; 404 1.2.8.2 yamt }; 405 1.2.8.2 yamt 406 1.2.8.2 yamt Again because I can have more than one device in kernel driver I need one parent 407 1.2.8.2 yamt dictionary and more children dictionaries. 408 1.2.8.2 yamt 409 1.2.8.2 yamt <dict> 410 1.2.8.2 yamt <dict ID="id"> 411 1.2.8.2 yamt <key>dev</key> 412 1.2.8.2 yamt <integer>...</integer> 413 1.2.8.2 yamt 414 1.2.8.2 yamt <key>name</key> 415 1.2.8.2 yamt <string>...</string> 416 1.2.8.2 yamt </dict> 417 1.2.8.2 yamt </dict> 418 1.2.8.2 yamt 419 1.2.8.2 yamt 2b) DM_DEV_RENAME 420 1.2.8.2 yamt This ioctl is called when libdevmapper want to rename device-mapper device. 421 1.2.8.2 yamt Libdevmapper library appends null terminated string to dm_ioctl struct in 422 1.2.8.2 yamt userspace.. 423 1.2.8.2 yamt 424 1.2.8.2 yamt <dict> 425 1.2.8.2 yamt <key>name</key> 426 1.2.8.2 yamt <string>...</string> 427 1.2.8.2 yamt </dict> 428 1.2.8.2 yamt 429 1.2.8.2 yamt 2c) DM_DEV_CREATE, DM_DEV_REMOVE, DM_DEV_STATUS 430 1.2.8.2 yamt Modify only dm_ioctl structure so I don't need to specify new structures. 431 1.2.8.2 yamt 432 1.2.8.2 yamt 433 1.2.8.2 yamt 3a) DM_TABLE_LOAD, DM_TABLE_STATUS 434 1.2.8.2 yamt DM_TABLE_LOAD ioctl loads table to device. DM_TABLE_STATUS send info about 435 1.2.8.2 yamt every table for selected device to userspace. Table is different for every 436 1.2.8.2 yamt target basic table structure is this 437 1.2.8.2 yamt 438 1.2.8.2 yamt {start} {length} {target} {additional information} 439 1.2.8.2 yamt 440 1.2.8.2 yamt e.g. 441 1.2.8.2 yamt 0 100 zero 442 1.2.8.2 yamt 443 1.2.8.2 yamt 0 100 linear /dev/wdba 384 444 1.2.8.2 yamt 445 1.2.8.2 yamt Protocol structure: 446 1.2.8.2 yamt 447 1.2.8.2 yamt struct dm_target_spec { 448 1.2.8.2 yamt uint64_t sector_start; 449 1.2.8.2 yamt uint64_t length; 450 1.2.8.2 yamt int32_t status; /* used when reading from kernel only */ 451 1.2.8.2 yamt 452 1.2.8.2 yamt uint32_t next; 453 1.2.8.2 yamt 454 1.2.8.2 yamt char target_type[DM_MAX_TYPE_NAME]; 455 1.2.8.2 yamt 456 1.2.8.2 yamt /* 457 1.2.8.2 yamt * Parameter string starts immediately after this object. 458 1.2.8.2 yamt * Be careful to add padding after string to ensure correct 459 1.2.8.2 yamt * alignment of subsequent dm_target_spec. 460 1.2.8.2 yamt */ 461 1.2.8.2 yamt }; 462 1.2.8.2 yamt 463 1.2.8.2 yamt <dict> 464 1.2.8.2 yamt <key>sector_start</key> 465 1.2.8.2 yamt <integer>...</integer> 466 1.2.8.2 yamt 467 1.2.8.2 yamt <key>length</key> 468 1.2.8.2 yamt <integer>...</integer> 469 1.2.8.2 yamt 470 1.2.8.2 yamt <key>target_type</key> 471 1.2.8.2 yamt <string>...</string> 472 1.2.8.2 yamt 473 1.2.8.2 yamt <key>aditional info</key> 474 1.2.8.2 yamt <string>...</string> 475 1.2.8.2 yamt </dict> 476
Indexes created Sun Oct 12 09:09:55 GMT 2025