/* * Copyright (C) 2006-2009 Red Hat, Inc. * * This file is released under the LGPL. */ #ifndef __DM_LOG_USERSPACE_H__#define __DM_LOG_USERSPACE_H__ #include <linux/dm-ioctl.h> /* For DM_UUID_LEN */ /* * The device-mapper userspace log module consists of a kernel component and * a user-space component.  The kernel component implements the API defined * in dm-dirty-log.h.  Its purpose is simply to pass the parameters and * return values of those API functions between kernel and user-space. * * Below are defined the 'request_types' - DM_ULOG_CTR, DM_ULOG_DTR, etc. * These request types represent the different functions in the device-mapper * dirty log API.  Each of these is described in more detail below. * * The user-space program must listen for requests from the kernel (representing * the various API functions) and process them. * * User-space begins by setting up the communication link (error checking * removed for clarity): *	fd = socket(PF_NETLINK, SOCK_DGRAM, NETLINK_CONNECTOR); *	addr.nl_family = AF_NETLINK; *	addr.nl_groups = CN_IDX_DM; *	addr.nl_pid = 0; *	r = bind(fd, (struct sockaddr *) &addr, sizeof(addr)); *	opt = addr.nl_groups; *	setsockopt(fd, SOL_NETLINK, NETLINK_ADD_MEMBERSHIP, &opt, sizeof(opt)); * * User-space will then wait to receive requests form the kernel, which it * will process as described below.  The requests are received in the form, * ((struct dm_ulog_request) + (additional data)).  Depending on the request * type, there may or may not be 'additional data'.  In the descriptions below, * you will see 'Payload-to-userspace' and 'Payload-to-kernel'.  The * 'Payload-to-userspace' is what the kernel sends in 'additional data' as * necessary parameters to complete the request.  The 'Payload-to-kernel' is * the 'additional data' returned to the kernel that contains the necessary * results of the request.  The 'data_size' field in the dm_ulog_request * structure denotes the availability and amount of payload data. */ /* * DM_ULOG_CTR corresponds to (found in dm-dirty-log.h): * int (*ctr)(struct dm_dirty_log *log, struct dm_target *ti, *	      unsigned argc, char **argv); * * Payload-to-userspace: *	A single string containing all the argv arguments separated by ' 's * Payload-to-kernel: *	A NUL-terminated string that is the name of the device that is used *	as the backing store for the log data.  'dm_get_device' will be called *	on this device.  ('dm_put_device' will be called on this device *	automatically after calling DM_ULOG_DTR.)  If there is no device needed *	for log data, 'data_size' in the dm_ulog_request struct should be 0. * * The UUID contained in the dm_ulog_request structure is the reference that * will be used by all request types to a specific log.  The constructor must * record this association with the instance created. * * When the request has been processed, user-space must return the * dm_ulog_request to the kernel - setting the 'error' field, filling the * data field with the log device if necessary, and setting 'data_size' * appropriately. */#define DM_ULOG_CTR                    1 /* * DM_ULOG_DTR corresponds to (found in dm-dirty-log.h): * void (*dtr)(struct dm_dirty_log *log); * * Payload-to-userspace: *	A single string containing all the argv arguments separated by ' 's * Payload-to-kernel: *	None.  ('data_size' in the dm_ulog_request struct should be 0.) * * The UUID contained in the dm_ulog_request structure is all that is * necessary to identify the log instance being destroyed.  There is no * payload data. * * When the request has been processed, user-space must return the * dm_ulog_request to the kernel - setting the 'error' field and clearing * 'data_size' appropriately. */#define DM_ULOG_DTR                    2 /* * DM_ULOG_PRESUSPEND corresponds to (found in dm-dirty-log.h): * int (*presuspend)(struct dm_dirty_log *log); * * Payload-to-userspace: *	None. * Payload-to-kernel: *	None. * * The UUID contained in the dm_ulog_request structure is all that is * necessary to identify the log instance being presuspended.  There is no * payload data. * * When the request has been processed, user-space must return the * dm_ulog_request to the kernel - setting the 'error' field and * 'data_size' appropriately. */#define DM_ULOG_PRESUSPEND             3 /* * DM_ULOG_POSTSUSPEND corresponds to (found in dm-dirty-log.h): * int (*postsuspend)(struct dm_dirty_log *log); * * Payload-to-userspace: *	None. * Payload-to-kernel: *	None. * * The UUID contained in the dm_ulog_request structure is all that is * necessary to identify the log instance being postsuspended.  There is no * payload data. * * When the request has been processed, user-space must return the * dm_ulog_request to the kernel - setting the 'error' field and * 'data_size' appropriately. */#define DM_ULOG_POSTSUSPEND            4 /* * DM_ULOG_RESUME corresponds to (found in dm-dirty-log.h): * int (*resume)(struct dm_dirty_log *log); * * Payload-to-userspace: *	None. * Payload-to-kernel: *	None. * * The UUID contained in the dm_ulog_request structure is all that is * necessary to identify the log instance being resumed.  There is no * payload data. * * When the request has been processed, user-space must return the * dm_ulog_request to the kernel - setting the 'error' field and * 'data_size' appropriately. */#define DM_ULOG_RESUME                 5 /* * DM_ULOG_GET_REGION_SIZE corresponds to (found in dm-dirty-log.h): * uint32_t (*get_region_size)(struct dm_dirty_log *log); * * Payload-to-userspace: *	None. * Payload-to-kernel: *	uint64_t - contains the region size * * The region size is something that was determined at constructor time. * It is returned in the payload area and 'data_size' is set to * reflect this. * * When the request has been processed, user-space must return the * dm_ulog_request to the kernel - setting the 'error' field appropriately. */#define DM_ULOG_GET_REGION_SIZE        6 /* * DM_ULOG_IS_CLEAN corresponds to (found in dm-dirty-log.h): * int (*is_clean)(struct dm_dirty_log *log, region_t region); * * Payload-to-userspace: *	uint64_t - the region to get clean status on * Payload-to-kernel: *	int64_t  - 1 if clean, 0 otherwise * * Payload is sizeof(uint64_t) and contains the region for which the clean * status is being made. * * When the request has been processed, user-space must return the * dm_ulog_request to the kernel - filling the payload with 0 (not clean) or * 1 (clean), setting 'data_size' and 'error' appropriately. */#define DM_ULOG_IS_CLEAN               7 /* * DM_ULOG_IN_SYNC corresponds to (found in dm-dirty-log.h): * int (*in_sync)(struct dm_dirty_log *log, region_t region, *		  int can_block); * * Payload-to-userspace: *	uint64_t - the region to get sync status on * Payload-to-kernel: *	int64_t - 1 if in-sync, 0 otherwise * * Exactly the same as 'is_clean' above, except this time asking "has the * region been recovered?" vs. "is the region not being modified?" */#define DM_ULOG_IN_SYNC                8 /* * DM_ULOG_FLUSH corresponds to (found in dm-dirty-log.h): * int (*flush)(struct dm_dirty_log *log); * * Payload-to-userspace: *	If the 'integrated_flush' directive is present in the constructor *	table, the payload is as same as DM_ULOG_MARK_REGION: *		uint64_t [] - region(s) to mark *	else *		None * Payload-to-kernel: *	None. * * If the 'integrated_flush' option was used during the creation of the * log, mark region requests are carried as payload in the flush request. * Piggybacking the mark requests in this way allows for fewer communications * between kernel and userspace. * * When the request has been processed, user-space must return the * dm_ulog_request to the kernel - setting the 'error' field and clearing * 'data_size' appropriately. */#define DM_ULOG_FLUSH                  9 /* * DM_ULOG_MARK_REGION corresponds to (found in dm-dirty-log.h): * void (*mark_region)(struct dm_dirty_log *log, region_t region); * * Payload-to-userspace: *	uint64_t [] - region(s) to mark * Payload-to-kernel: *	None. * * Incoming payload contains the one or more regions to mark dirty. * The number of regions contained in the payload can be determined from * 'data_size/sizeof(uint64_t)'. * * When the request has been processed, user-space must return the * dm_ulog_request to the kernel - setting the 'error' field and clearing * 'data_size' appropriately. */#define DM_ULOG_MARK_REGION           10 /* * DM_ULOG_CLEAR_REGION corresponds to (found in dm-dirty-log.h): * void (*clear_region)(struct dm_dirty_log *log, region_t region); * * Payload-to-userspace: *	uint64_t [] - region(s) to clear * Payload-to-kernel: *	None. * * Incoming payload contains the one or more regions to mark clean. * The number of regions contained in the payload can be determined from * 'data_size/sizeof(uint64_t)'. * * When the request has been processed, user-space must return the * dm_ulog_request to the kernel - setting the 'error' field and clearing * 'data_size' appropriately. */#define DM_ULOG_CLEAR_REGION          11 /* * DM_ULOG_GET_RESYNC_WORK corresponds to (found in dm-dirty-log.h): * int (*get_resync_work)(struct dm_dirty_log *log, region_t *region); * * Payload-to-userspace: *	None. * Payload-to-kernel: *	{ *		int64_t i; -- 1 if recovery necessary, 0 otherwise *		uint64_t r; -- The region to recover if i=1 *	} * 'data_size' should be set appropriately. * * When the request has been processed, user-space must return the * dm_ulog_request to the kernel - setting the 'error' field appropriately. */#define DM_ULOG_GET_RESYNC_WORK       12 /* * DM_ULOG_SET_REGION_SYNC corresponds to (found in dm-dirty-log.h): * void (*set_region_sync)(struct dm_dirty_log *log, *			   region_t region, int in_sync); * * Payload-to-userspace: *	{ *		uint64_t - region to set sync state on *		int64_t  - 0 if not-in-sync, 1 if in-sync *	} * Payload-to-kernel: *	None. * * When the request has been processed, user-space must return the * dm_ulog_request to the kernel - setting the 'error' field and clearing * 'data_size' appropriately. */#define DM_ULOG_SET_REGION_SYNC       13 /* * DM_ULOG_GET_SYNC_COUNT corresponds to (found in dm-dirty-log.h): * region_t (*get_sync_count)(struct dm_dirty_log *log); * * Payload-to-userspace: *	None. * Payload-to-kernel: *	uint64_t - the number of in-sync regions * * No incoming payload.  Kernel-bound payload contains the number of * regions that are in-sync (in a size_t). * * When the request has been processed, user-space must return the * dm_ulog_request to the kernel - setting the 'error' field and * 'data_size' appropriately. */#define DM_ULOG_GET_SYNC_COUNT        14 /* * DM_ULOG_STATUS_INFO corresponds to (found in dm-dirty-log.h): * int (*status)(struct dm_dirty_log *log, STATUSTYPE_INFO, *		 char *result, unsigned maxlen); * * Payload-to-userspace: *	None. * Payload-to-kernel: *	Character string containing STATUSTYPE_INFO * * When the request has been processed, user-space must return the * dm_ulog_request to the kernel - setting the 'error' field and * 'data_size' appropriately. */#define DM_ULOG_STATUS_INFO           15 /* * DM_ULOG_STATUS_TABLE corresponds to (found in dm-dirty-log.h): * int (*status)(struct dm_dirty_log *log, STATUSTYPE_TABLE, *		 char *result, unsigned maxlen); * * Payload-to-userspace: *	None. * Payload-to-kernel: *	Character string containing STATUSTYPE_TABLE * * When the request has been processed, user-space must return the * dm_ulog_request to the kernel - setting the 'error' field and * 'data_size' appropriately. */#define DM_ULOG_STATUS_TABLE          16 /* * DM_ULOG_IS_REMOTE_RECOVERING corresponds to (found in dm-dirty-log.h): * int (*is_remote_recovering)(struct dm_dirty_log *log, region_t region); * * Payload-to-userspace: *	uint64_t - region to determine recovery status on * Payload-to-kernel: *	{ *		int64_t is_recovering;  -- 0 if no, 1 if yes *		uint64_t in_sync_hint;  -- lowest region still needing resync *	} * * When the request has been processed, user-space must return the * dm_ulog_request to the kernel - setting the 'error' field and * 'data_size' appropriately. */#define DM_ULOG_IS_REMOTE_RECOVERING  17 /* * (DM_ULOG_REQUEST_MASK & request_type) to get the request type * * Payload-to-userspace: *	A single string containing all the argv arguments separated by ' 's * Payload-to-kernel: *	None.  ('data_size' in the dm_ulog_request struct should be 0.) * * We are reserving 8 bits of the 32-bit 'request_type' field for the * various request types above.  The remaining 24-bits are currently * set to zero and are reserved for future use and compatibility concerns. * * User-space should always use DM_ULOG_REQUEST_TYPE to acquire the * request type from the 'request_type' field to maintain forward compatibility. */#define DM_ULOG_REQUEST_MASK 0xFF#define DM_ULOG_REQUEST_TYPE(request_type) \	(DM_ULOG_REQUEST_MASK & (request_type)) /* * DM_ULOG_REQUEST_VERSION is incremented when there is a * change to the way information is passed between kernel * and userspace.  This could be a structure change of * dm_ulog_request or a change in the way requests are * issued/handled.  Changes are outlined here: *	version 1:  Initial implementation *	version 2:  DM_ULOG_CTR allowed to return a string containing a *	            device name that is to be registered with DM via *	            'dm_get_device'. *	version 3:  DM_ULOG_FLUSH is capable of carrying payload for marking *		    regions.  This "integrated flush" reduces the number of *		    requests between the kernel and userspace by effectively *		    merging 'mark' and 'flush' requests.  A constructor table *		    argument ('integrated_flush') is required to turn this *		    feature on, so it is backwards compatible with older *		    userspace versions. */#define DM_ULOG_REQUEST_VERSION 3 struct dm_ulog_request {	/*	 * The local unique identifier (luid) and the universally unique	 * identifier (uuid) are used to tie a request to a specific	 * mirror log.  A single machine log could probably make due with	 * just the 'luid', but a cluster-aware log must use the 'uuid' and	 * the 'luid'.  The uuid is what is required for node to node	 * communication concerning a particular log, but the 'luid' helps	 * differentiate between logs that are being swapped and have the	 * same 'uuid'.  (Think "live" and "inactive" device-mapper tables.)	 */	uint64_t luid;	char uuid[DM_UUID_LEN];	char padding[3];        /* Padding because DM_UUID_LEN = 129 */ 	uint32_t version;       /* See DM_ULOG_REQUEST_VERSION */	int32_t error;          /* Used to report back processing errors */ 	uint32_t seq;           /* Sequence number for request */	uint32_t request_type;  /* DM_ULOG_* defined above */	uint32_t data_size;     /* How much data (not including this struct) */ 	char data[0];}; #endif /* __DM_LOG_USERSPACE_H__ */