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- /*
- * 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:
- * None. ('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 assotiation with instance created.
- *
- * 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_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:
- * None.
- * Payload-to-kernel:
- * None.
- *
- * No incoming or outgoing payload. Simply flush log state to disk.
- *
- * 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 aquire 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))
-
- 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[7]; /* Padding because DM_UUID_LEN = 129 */
-
- 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__ */
-