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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:

 *      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__ */