---

---

---

001: /*
002:  * Copyright (C) 2006-2009 Red Hat, Inc.
003:  *
004:  * This file is released under the LGPL.
005:  */
006: 
007: #ifndef __DM_LOG_USERSPACE_H__
008: #define __DM_LOG_USERSPACE_H__
009: 
010: #include <linux/dm-ioctl.h> /* For DM_UUID_LEN */
011: 
012: /*
013:  * The device-mapper userspace log module consists of a kernel component and
014:  * a user-space component.  The kernel component implements the API defined
015:  * in dm-dirty-log.h.  Its purpose is simply to pass the parameters and
016:  * return values of those API functions between kernel and user-space.
017:  *
018:  * Below are defined the 'request_types' - DM_ULOG_CTR, DM_ULOG_DTR, etc.
019:  * These request types represent the different functions in the device-mapper
020:  * dirty log API.  Each of these is described in more detail below.
021:  *
022:  * The user-space program must listen for requests from the kernel (representing
023:  * the various API functions) and process them.
024:  *
025:  * User-space begins by setting up the communication link (error checking
026:  * removed for clarity):
027:  *      fd = socket(PF_NETLINK, SOCK_DGRAM, NETLINK_CONNECTOR);
028:  *      addr.nl_family = AF_NETLINK;
029:  *      addr.nl_groups = CN_IDX_DM;
030:  *      addr.nl_pid = 0;
031:  *      r = bind(fd, (struct sockaddr *) &addr, sizeof(addr));
032:  *      opt = addr.nl_groups;
033:  *      setsockopt(fd, SOL_NETLINK, NETLINK_ADD_MEMBERSHIP, &opt, sizeof(opt));
034:  *
035:  * User-space will then wait to receive requests form the kernel, which it
036:  * will process as described below.  The requests are received in the form,
037:  * ((struct dm_ulog_request) + (additional data)).  Depending on the request
038:  * type, there may or may not be 'additional data'.  In the descriptions below,
039:  * you will see 'Payload-to-userspace' and 'Payload-to-kernel'.  The
040:  * 'Payload-to-userspace' is what the kernel sends in 'additional data' as
041:  * necessary parameters to complete the request.  The 'Payload-to-kernel' is
042:  * the 'additional data' returned to the kernel that contains the necessary
043:  * results of the request.  The 'data_size' field in the dm_ulog_request
044:  * structure denotes the availability and amount of payload data.
045:  */
046: 
047: /*
048:  * DM_ULOG_CTR corresponds to (found in dm-dirty-log.h):
049:  * int (*ctr)(struct dm_dirty_log *log, struct dm_target *ti,
050:  *            unsigned argc, char **argv);
051:  *
052:  * Payload-to-userspace:
053:  *      A single string containing all the argv arguments separated by ' 's
054:  * Payload-to-kernel:
055:  *      A NUL-terminated string that is the name of the device that is used
056:  *      as the backing store for the log data.  'dm_get_device' will be called
057:  *      on this device.  ('dm_put_device' will be called on this device
058:  *      automatically after calling DM_ULOG_DTR.)  If there is no device needed
059:  *      for log data, 'data_size' in the dm_ulog_request struct should be 0.
060:  *
061:  * The UUID contained in the dm_ulog_request structure is the reference that
062:  * will be used by all request types to a specific log.  The constructor must
063:  * record this association with the instance created.
064:  *
065:  * When the request has been processed, user-space must return the
066:  * dm_ulog_request to the kernel - setting the 'error' field, filling the
067:  * data field with the log device if necessary, and setting 'data_size'
068:  * appropriately.
069:  */
070: #define DM_ULOG_CTR                    1
071: 
072: /*
073:  * DM_ULOG_DTR corresponds to (found in dm-dirty-log.h):
074:  * void (*dtr)(struct dm_dirty_log *log);
075:  *
076:  * Payload-to-userspace:
077:  *      A single string containing all the argv arguments separated by ' 's
078:  * Payload-to-kernel:
079:  *      None.  ('data_size' in the dm_ulog_request struct should be 0.)
080:  *
081:  * The UUID contained in the dm_ulog_request structure is all that is
082:  * necessary to identify the log instance being destroyed.  There is no
083:  * payload data.
084:  *
085:  * When the request has been processed, user-space must return the
086:  * dm_ulog_request to the kernel - setting the 'error' field and clearing
087:  * 'data_size' appropriately.
088:  */
089: #define DM_ULOG_DTR                    2
090: 
091: /*
092:  * DM_ULOG_PRESUSPEND corresponds to (found in dm-dirty-log.h):
093:  * int (*presuspend)(struct dm_dirty_log *log);
094:  *
095:  * Payload-to-userspace:
096:  *      None.
097:  * Payload-to-kernel:
098:  *      None.
099:  *
100:  * The UUID contained in the dm_ulog_request structure is all that is
101:  * necessary to identify the log instance being presuspended.  There is no
102:  * payload data.
103:  *
104:  * When the request has been processed, user-space must return the
105:  * dm_ulog_request to the kernel - setting the 'error' field and
106:  * 'data_size' appropriately.
107:  */
108: #define DM_ULOG_PRESUSPEND             3
109: 
110: /*
111:  * DM_ULOG_POSTSUSPEND corresponds to (found in dm-dirty-log.h):
112:  * int (*postsuspend)(struct dm_dirty_log *log);
113:  *
114:  * Payload-to-userspace:
115:  *      None.
116:  * Payload-to-kernel:
117:  *      None.
118:  *
119:  * The UUID contained in the dm_ulog_request structure is all that is
120:  * necessary to identify the log instance being postsuspended.  There is no
121:  * payload data.
122:  *
123:  * When the request has been processed, user-space must return the
124:  * dm_ulog_request to the kernel - setting the 'error' field and
125:  * 'data_size' appropriately.
126:  */
127: #define DM_ULOG_POSTSUSPEND            4
128: 
129: /*
130:  * DM_ULOG_RESUME corresponds to (found in dm-dirty-log.h):
131:  * int (*resume)(struct dm_dirty_log *log);
132:  *
133:  * Payload-to-userspace:
134:  *      None.
135:  * Payload-to-kernel:
136:  *      None.
137:  *
138:  * The UUID contained in the dm_ulog_request structure is all that is
139:  * necessary to identify the log instance being resumed.  There is no
140:  * payload data.
141:  *
142:  * When the request has been processed, user-space must return the
143:  * dm_ulog_request to the kernel - setting the 'error' field and
144:  * 'data_size' appropriately.
145:  */
146: #define DM_ULOG_RESUME                 5
147: 
148: /*
149:  * DM_ULOG_GET_REGION_SIZE corresponds to (found in dm-dirty-log.h):
150:  * uint32_t (*get_region_size)(struct dm_dirty_log *log);
151:  *
152:  * Payload-to-userspace:
153:  *      None.
154:  * Payload-to-kernel:
155:  *      uint64_t - contains the region size
156:  *
157:  * The region size is something that was determined at constructor time.
158:  * It is returned in the payload area and 'data_size' is set to
159:  * reflect this.
160:  *
161:  * When the request has been processed, user-space must return the
162:  * dm_ulog_request to the kernel - setting the 'error' field appropriately.
163:  */
164: #define DM_ULOG_GET_REGION_SIZE        6
165: 
166: /*
167:  * DM_ULOG_IS_CLEAN corresponds to (found in dm-dirty-log.h):
168:  * int (*is_clean)(struct dm_dirty_log *log, region_t region);
169:  *
170:  * Payload-to-userspace:
171:  *      uint64_t - the region to get clean status on
172:  * Payload-to-kernel:
173:  *      int64_t  - 1 if clean, 0 otherwise
174:  *
175:  * Payload is sizeof(uint64_t) and contains the region for which the clean
176:  * status is being made.
177:  *
178:  * When the request has been processed, user-space must return the
179:  * dm_ulog_request to the kernel - filling the payload with 0 (not clean) or
180:  * 1 (clean), setting 'data_size' and 'error' appropriately.
181:  */
182: #define DM_ULOG_IS_CLEAN               7
183: 
184: /*
185:  * DM_ULOG_IN_SYNC corresponds to (found in dm-dirty-log.h):
186:  * int (*in_sync)(struct dm_dirty_log *log, region_t region,
187:  *                int can_block);
188:  *
189:  * Payload-to-userspace:
190:  *      uint64_t - the region to get sync status on
191:  * Payload-to-kernel:
192:  *      int64_t - 1 if in-sync, 0 otherwise
193:  *
194:  * Exactly the same as 'is_clean' above, except this time asking "has the
195:  * region been recovered?" vs. "is the region not being modified?"
196:  */
197: #define DM_ULOG_IN_SYNC                8
198: 
199: /*
200:  * DM_ULOG_FLUSH corresponds to (found in dm-dirty-log.h):
201:  * int (*flush)(struct dm_dirty_log *log);
202:  *
203:  * Payload-to-userspace:
204:  *      None.
205:  * Payload-to-kernel:
206:  *      None.
207:  *
208:  * No incoming or outgoing payload.  Simply flush log state to disk.
209:  *
210:  * When the request has been processed, user-space must return the
211:  * dm_ulog_request to the kernel - setting the 'error' field and clearing
212:  * 'data_size' appropriately.
213:  */
214: #define DM_ULOG_FLUSH                  9
215: 
216: /*
217:  * DM_ULOG_MARK_REGION corresponds to (found in dm-dirty-log.h):
218:  * void (*mark_region)(struct dm_dirty_log *log, region_t region);
219:  *
220:  * Payload-to-userspace:
221:  *      uint64_t [] - region(s) to mark
222:  * Payload-to-kernel:
223:  *      None.
224:  *
225:  * Incoming payload contains the one or more regions to mark dirty.
226:  * The number of regions contained in the payload can be determined from
227:  * 'data_size/sizeof(uint64_t)'.
228:  *
229:  * When the request has been processed, user-space must return the
230:  * dm_ulog_request to the kernel - setting the 'error' field and clearing
231:  * 'data_size' appropriately.
232:  */
233: #define DM_ULOG_MARK_REGION           10
234: 
235: /*
236:  * DM_ULOG_CLEAR_REGION corresponds to (found in dm-dirty-log.h):
237:  * void (*clear_region)(struct dm_dirty_log *log, region_t region);
238:  *
239:  * Payload-to-userspace:
240:  *      uint64_t [] - region(s) to clear
241:  * Payload-to-kernel:
242:  *      None.
243:  *
244:  * Incoming payload contains the one or more regions to mark clean.
245:  * The number of regions contained in the payload can be determined from
246:  * 'data_size/sizeof(uint64_t)'.
247:  *
248:  * When the request has been processed, user-space must return the
249:  * dm_ulog_request to the kernel - setting the 'error' field and clearing
250:  * 'data_size' appropriately.
251:  */
252: #define DM_ULOG_CLEAR_REGION          11
253: 
254: /*
255:  * DM_ULOG_GET_RESYNC_WORK corresponds to (found in dm-dirty-log.h):
256:  * int (*get_resync_work)(struct dm_dirty_log *log, region_t *region);
257:  *
258:  * Payload-to-userspace:
259:  *      None.
260:  * Payload-to-kernel:
261:  *      {
262:  *              int64_t i; -- 1 if recovery necessary, 0 otherwise
263:  *              uint64_t r; -- The region to recover if i=1
264:  *      }
265:  * 'data_size' should be set appropriately.
266:  *
267:  * When the request has been processed, user-space must return the
268:  * dm_ulog_request to the kernel - setting the 'error' field appropriately.
269:  */
270: #define DM_ULOG_GET_RESYNC_WORK       12
271: 
272: /*
273:  * DM_ULOG_SET_REGION_SYNC corresponds to (found in dm-dirty-log.h):
274:  * void (*set_region_sync)(struct dm_dirty_log *log,
275:  *                         region_t region, int in_sync);
276:  *
277:  * Payload-to-userspace:
278:  *      {
279:  *              uint64_t - region to set sync state on
280:  *              int64_t  - 0 if not-in-sync, 1 if in-sync
281:  *      }
282:  * Payload-to-kernel:
283:  *      None.
284:  *
285:  * When the request has been processed, user-space must return the
286:  * dm_ulog_request to the kernel - setting the 'error' field and clearing
287:  * 'data_size' appropriately.
288:  */
289: #define DM_ULOG_SET_REGION_SYNC       13
290: 
291: /*
292:  * DM_ULOG_GET_SYNC_COUNT corresponds to (found in dm-dirty-log.h):
293:  * region_t (*get_sync_count)(struct dm_dirty_log *log);
294:  *
295:  * Payload-to-userspace:
296:  *      None.
297:  * Payload-to-kernel:
298:  *      uint64_t - the number of in-sync regions
299:  *
300:  * No incoming payload.  Kernel-bound payload contains the number of
301:  * regions that are in-sync (in a size_t).
302:  *
303:  * When the request has been processed, user-space must return the
304:  * dm_ulog_request to the kernel - setting the 'error' field and
305:  * 'data_size' appropriately.
306:  */
307: #define DM_ULOG_GET_SYNC_COUNT        14
308: 
309: /*
310:  * DM_ULOG_STATUS_INFO corresponds to (found in dm-dirty-log.h):
311:  * int (*status)(struct dm_dirty_log *log, STATUSTYPE_INFO,
312:  *               char *result, unsigned maxlen);
313:  *
314:  * Payload-to-userspace:
315:  *      None.
316:  * Payload-to-kernel:
317:  *      Character string containing STATUSTYPE_INFO
318:  *
319:  * When the request has been processed, user-space must return the
320:  * dm_ulog_request to the kernel - setting the 'error' field and
321:  * 'data_size' appropriately.
322:  */
323: #define DM_ULOG_STATUS_INFO           15
324: 
325: /*
326:  * DM_ULOG_STATUS_TABLE corresponds to (found in dm-dirty-log.h):
327:  * int (*status)(struct dm_dirty_log *log, STATUSTYPE_TABLE,
328:  *               char *result, unsigned maxlen);
329:  *
330:  * Payload-to-userspace:
331:  *      None.
332:  * Payload-to-kernel:
333:  *      Character string containing STATUSTYPE_TABLE
334:  *
335:  * When the request has been processed, user-space must return the
336:  * dm_ulog_request to the kernel - setting the 'error' field and
337:  * 'data_size' appropriately.
338:  */
339: #define DM_ULOG_STATUS_TABLE          16
340: 
341: /*
342:  * DM_ULOG_IS_REMOTE_RECOVERING corresponds to (found in dm-dirty-log.h):
343:  * int (*is_remote_recovering)(struct dm_dirty_log *log, region_t region);
344:  *
345:  * Payload-to-userspace:
346:  *      uint64_t - region to determine recovery status on
347:  * Payload-to-kernel:
348:  *      {
349:  *              int64_t is_recovering;  -- 0 if no, 1 if yes
350:  *              uint64_t in_sync_hint;  -- lowest region still needing resync
351:  *      }
352:  *
353:  * When the request has been processed, user-space must return the
354:  * dm_ulog_request to the kernel - setting the 'error' field and
355:  * 'data_size' appropriately.
356:  */
357: #define DM_ULOG_IS_REMOTE_RECOVERING  17
358: 
359: /*
360:  * (DM_ULOG_REQUEST_MASK & request_type) to get the request type
361:  *
362:  * Payload-to-userspace:
363:  *      A single string containing all the argv arguments separated by ' 's
364:  * Payload-to-kernel:
365:  *      None.  ('data_size' in the dm_ulog_request struct should be 0.)
366:  *
367:  * We are reserving 8 bits of the 32-bit 'request_type' field for the
368:  * various request types above.  The remaining 24-bits are currently
369:  * set to zero and are reserved for future use and compatibility concerns.
370:  *
371:  * User-space should always use DM_ULOG_REQUEST_TYPE to acquire the
372:  * request type from the 'request_type' field to maintain forward compatibility.
373:  */
374: #define DM_ULOG_REQUEST_MASK 0xFF
375: #define DM_ULOG_REQUEST_TYPE(request_type) \
376:         (DM_ULOG_REQUEST_MASK & (request_type))
377: 
378: /*
379:  * DM_ULOG_REQUEST_VERSION is incremented when there is a
380:  * change to the way information is passed between kernel
381:  * and userspace.  This could be a structure change of
382:  * dm_ulog_request or a change in the way requests are
383:  * issued/handled.  Changes are outlined here:
384:  *      version 1:  Initial implementation
385:  *      version 2:  DM_ULOG_CTR allowed to return a string containing a
386:  *                  device name that is to be registered with DM via
387:  *                  'dm_get_device'.
388:  */
389: #define DM_ULOG_REQUEST_VERSION 2
390: 
391: struct dm_ulog_request {
392:         /*
393:          * The local unique identifier (luid) and the universally unique
394:          * identifier (uuid) are used to tie a request to a specific
395:          * mirror log.  A single machine log could probably make due with
396:          * just the 'luid', but a cluster-aware log must use the 'uuid' and
397:          * the 'luid'.  The uuid is what is required for node to node
398:          * communication concerning a particular log, but the 'luid' helps
399:          * differentiate between logs that are being swapped and have the
400:          * same 'uuid'.  (Think "live" and "inactive" device-mapper tables.)
401:          */
402:         uint64_t luid;
403:         char uuid[DM_UUID_LEN];
404:         char padding[3];        /* Padding because DM_UUID_LEN = 129 */
405: 
406:         uint32_t version;       /* See DM_ULOG_REQUEST_VERSION */
407:         int32_t error;          /* Used to report back processing errors */
408: 
409:         uint32_t seq;           /* Sequence number for request */
410:         uint32_t request_type;  /* DM_ULOG_* defined above */
411:         uint32_t data_size;     /* How much data (not including this struct) */
412: 
413:         char data[0];
414: };
415: 
416: #endif /* __DM_LOG_USERSPACE_H__ */
417: 

---

---

---