433 lines
15 KiB
C
433 lines
15 KiB
C
/* SPDX-License-Identifier: LGPL-2.0+ WITH Linux-syscall-note */
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/*
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* Copyright (C) 2006-2009 Red Hat, Inc.
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*
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* This file is released under the LGPL.
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*/
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#ifndef __DM_LOG_USERSPACE_H__
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#define __DM_LOG_USERSPACE_H__
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#include <linux/types.h>
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#include <linux/dm-ioctl.h> /* For DM_UUID_LEN */
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/*
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* The device-mapper userspace log module consists of a kernel component and
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* a user-space component. The kernel component implements the API defined
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* in dm-dirty-log.h. Its purpose is simply to pass the parameters and
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* return values of those API functions between kernel and user-space.
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*
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* Below are defined the 'request_types' - DM_ULOG_CTR, DM_ULOG_DTR, etc.
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* These request types represent the different functions in the device-mapper
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* dirty log API. Each of these is described in more detail below.
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*
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* The user-space program must listen for requests from the kernel (representing
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* the various API functions) and process them.
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*
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* User-space begins by setting up the communication link (error checking
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* removed for clarity):
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* fd = socket(PF_NETLINK, SOCK_DGRAM, NETLINK_CONNECTOR);
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* addr.nl_family = AF_NETLINK;
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* addr.nl_groups = CN_IDX_DM;
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* addr.nl_pid = 0;
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* r = bind(fd, (struct sockaddr *) &addr, sizeof(addr));
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* opt = addr.nl_groups;
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* setsockopt(fd, SOL_NETLINK, NETLINK_ADD_MEMBERSHIP, &opt, sizeof(opt));
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*
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* User-space will then wait to receive requests form the kernel, which it
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* will process as described below. The requests are received in the form,
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* ((struct dm_ulog_request) + (additional data)). Depending on the request
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* type, there may or may not be 'additional data'. In the descriptions below,
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* you will see 'Payload-to-userspace' and 'Payload-to-kernel'. The
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* 'Payload-to-userspace' is what the kernel sends in 'additional data' as
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* necessary parameters to complete the request. The 'Payload-to-kernel' is
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* the 'additional data' returned to the kernel that contains the necessary
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* results of the request. The 'data_size' field in the dm_ulog_request
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* structure denotes the availability and amount of payload data.
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*/
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/*
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* DM_ULOG_CTR corresponds to (found in dm-dirty-log.h):
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* int (*ctr)(struct dm_dirty_log *log, struct dm_target *ti,
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* unsigned argc, char **argv);
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*
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* Payload-to-userspace:
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* A single string containing all the argv arguments separated by ' 's
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* Payload-to-kernel:
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* A NUL-terminated string that is the name of the device that is used
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* as the backing store for the log data. 'dm_get_device' will be called
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* on this device. ('dm_put_device' will be called on this device
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* automatically after calling DM_ULOG_DTR.) If there is no device needed
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* for log data, 'data_size' in the dm_ulog_request struct should be 0.
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*
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* The UUID contained in the dm_ulog_request structure is the reference that
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* will be used by all request types to a specific log. The constructor must
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* record this association with the instance created.
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*
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* When the request has been processed, user-space must return the
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* dm_ulog_request to the kernel - setting the 'error' field, filling the
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* data field with the log device if necessary, and setting 'data_size'
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* appropriately.
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*/
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#define DM_ULOG_CTR 1
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/*
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* DM_ULOG_DTR corresponds to (found in dm-dirty-log.h):
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* void (*dtr)(struct dm_dirty_log *log);
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*
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* Payload-to-userspace:
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* A single string containing all the argv arguments separated by ' 's
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* Payload-to-kernel:
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* None. ('data_size' in the dm_ulog_request struct should be 0.)
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*
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* The UUID contained in the dm_ulog_request structure is all that is
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* necessary to identify the log instance being destroyed. There is no
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* payload data.
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*
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* When the request has been processed, user-space must return the
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* dm_ulog_request to the kernel - setting the 'error' field and clearing
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* 'data_size' appropriately.
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*/
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#define DM_ULOG_DTR 2
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/*
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* DM_ULOG_PRESUSPEND corresponds to (found in dm-dirty-log.h):
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* int (*presuspend)(struct dm_dirty_log *log);
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*
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* Payload-to-userspace:
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* None.
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* Payload-to-kernel:
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* None.
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*
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* The UUID contained in the dm_ulog_request structure is all that is
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* necessary to identify the log instance being presuspended. There is no
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* payload data.
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*
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* When the request has been processed, user-space must return the
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* dm_ulog_request to the kernel - setting the 'error' field and
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* 'data_size' appropriately.
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*/
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#define DM_ULOG_PRESUSPEND 3
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/*
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* DM_ULOG_POSTSUSPEND corresponds to (found in dm-dirty-log.h):
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* int (*postsuspend)(struct dm_dirty_log *log);
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*
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* Payload-to-userspace:
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* None.
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* Payload-to-kernel:
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* None.
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*
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* The UUID contained in the dm_ulog_request structure is all that is
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* necessary to identify the log instance being postsuspended. There is no
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* payload data.
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*
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* When the request has been processed, user-space must return the
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* dm_ulog_request to the kernel - setting the 'error' field and
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* 'data_size' appropriately.
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*/
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#define DM_ULOG_POSTSUSPEND 4
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/*
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* DM_ULOG_RESUME corresponds to (found in dm-dirty-log.h):
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* int (*resume)(struct dm_dirty_log *log);
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*
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* Payload-to-userspace:
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* None.
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* Payload-to-kernel:
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* None.
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*
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* The UUID contained in the dm_ulog_request structure is all that is
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* necessary to identify the log instance being resumed. There is no
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* payload data.
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*
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* When the request has been processed, user-space must return the
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* dm_ulog_request to the kernel - setting the 'error' field and
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* 'data_size' appropriately.
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*/
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#define DM_ULOG_RESUME 5
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/*
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* DM_ULOG_GET_REGION_SIZE corresponds to (found in dm-dirty-log.h):
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* __u32 (*get_region_size)(struct dm_dirty_log *log);
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*
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* Payload-to-userspace:
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* None.
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* Payload-to-kernel:
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* __u64 - contains the region size
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*
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* The region size is something that was determined at constructor time.
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* It is returned in the payload area and 'data_size' is set to
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* reflect this.
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*
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* When the request has been processed, user-space must return the
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* dm_ulog_request to the kernel - setting the 'error' field appropriately.
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*/
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#define DM_ULOG_GET_REGION_SIZE 6
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/*
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* DM_ULOG_IS_CLEAN corresponds to (found in dm-dirty-log.h):
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* int (*is_clean)(struct dm_dirty_log *log, region_t region);
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*
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* Payload-to-userspace:
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* __u64 - the region to get clean status on
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* Payload-to-kernel:
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* __s64 - 1 if clean, 0 otherwise
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*
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* Payload is sizeof(__u64) and contains the region for which the clean
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* status is being made.
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*
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* When the request has been processed, user-space must return the
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* dm_ulog_request to the kernel - filling the payload with 0 (not clean) or
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* 1 (clean), setting 'data_size' and 'error' appropriately.
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*/
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#define DM_ULOG_IS_CLEAN 7
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/*
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* DM_ULOG_IN_SYNC corresponds to (found in dm-dirty-log.h):
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* int (*in_sync)(struct dm_dirty_log *log, region_t region,
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* int can_block);
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*
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* Payload-to-userspace:
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* __u64 - the region to get sync status on
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* Payload-to-kernel:
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* __s64 - 1 if in-sync, 0 otherwise
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*
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* Exactly the same as 'is_clean' above, except this time asking "has the
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* region been recovered?" vs. "is the region not being modified?"
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*/
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#define DM_ULOG_IN_SYNC 8
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/*
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* DM_ULOG_FLUSH corresponds to (found in dm-dirty-log.h):
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* int (*flush)(struct dm_dirty_log *log);
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*
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* Payload-to-userspace:
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* If the 'integrated_flush' directive is present in the constructor
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* table, the payload is as same as DM_ULOG_MARK_REGION:
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* __u64 [] - region(s) to mark
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* else
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* None
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* Payload-to-kernel:
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* None.
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*
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* If the 'integrated_flush' option was used during the creation of the
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* log, mark region requests are carried as payload in the flush request.
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* Piggybacking the mark requests in this way allows for fewer communications
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* between kernel and userspace.
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*
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* When the request has been processed, user-space must return the
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* dm_ulog_request to the kernel - setting the 'error' field and clearing
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* 'data_size' appropriately.
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*/
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#define DM_ULOG_FLUSH 9
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/*
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* DM_ULOG_MARK_REGION corresponds to (found in dm-dirty-log.h):
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* void (*mark_region)(struct dm_dirty_log *log, region_t region);
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*
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* Payload-to-userspace:
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* __u64 [] - region(s) to mark
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* Payload-to-kernel:
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* None.
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*
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* Incoming payload contains the one or more regions to mark dirty.
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* The number of regions contained in the payload can be determined from
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* 'data_size/sizeof(__u64)'.
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*
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* When the request has been processed, user-space must return the
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* dm_ulog_request to the kernel - setting the 'error' field and clearing
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* 'data_size' appropriately.
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*/
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#define DM_ULOG_MARK_REGION 10
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/*
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* DM_ULOG_CLEAR_REGION corresponds to (found in dm-dirty-log.h):
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* void (*clear_region)(struct dm_dirty_log *log, region_t region);
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*
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* Payload-to-userspace:
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* __u64 [] - region(s) to clear
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* Payload-to-kernel:
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* None.
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*
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* Incoming payload contains the one or more regions to mark clean.
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* The number of regions contained in the payload can be determined from
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* 'data_size/sizeof(__u64)'.
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*
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* When the request has been processed, user-space must return the
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* dm_ulog_request to the kernel - setting the 'error' field and clearing
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* 'data_size' appropriately.
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*/
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#define DM_ULOG_CLEAR_REGION 11
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/*
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* DM_ULOG_GET_RESYNC_WORK corresponds to (found in dm-dirty-log.h):
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* int (*get_resync_work)(struct dm_dirty_log *log, region_t *region);
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*
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* Payload-to-userspace:
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* None.
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* Payload-to-kernel:
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* {
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* __s64 i; -- 1 if recovery necessary, 0 otherwise
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* __u64 r; -- The region to recover if i=1
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* }
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* 'data_size' should be set appropriately.
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*
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* When the request has been processed, user-space must return the
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* dm_ulog_request to the kernel - setting the 'error' field appropriately.
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*/
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#define DM_ULOG_GET_RESYNC_WORK 12
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/*
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* DM_ULOG_SET_REGION_SYNC corresponds to (found in dm-dirty-log.h):
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* void (*set_region_sync)(struct dm_dirty_log *log,
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* region_t region, int in_sync);
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*
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* Payload-to-userspace:
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* {
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* __u64 - region to set sync state on
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* __s64 - 0 if not-in-sync, 1 if in-sync
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* }
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* Payload-to-kernel:
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* None.
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*
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* When the request has been processed, user-space must return the
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* dm_ulog_request to the kernel - setting the 'error' field and clearing
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* 'data_size' appropriately.
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*/
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#define DM_ULOG_SET_REGION_SYNC 13
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/*
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* DM_ULOG_GET_SYNC_COUNT corresponds to (found in dm-dirty-log.h):
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* region_t (*get_sync_count)(struct dm_dirty_log *log);
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*
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* Payload-to-userspace:
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* None.
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* Payload-to-kernel:
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* __u64 - the number of in-sync regions
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*
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* No incoming payload. Kernel-bound payload contains the number of
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* regions that are in-sync (in a size_t).
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*
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* When the request has been processed, user-space must return the
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* dm_ulog_request to the kernel - setting the 'error' field and
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* 'data_size' appropriately.
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*/
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#define DM_ULOG_GET_SYNC_COUNT 14
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/*
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* DM_ULOG_STATUS_INFO corresponds to (found in dm-dirty-log.h):
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* int (*status)(struct dm_dirty_log *log, STATUSTYPE_INFO,
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* char *result, unsigned maxlen);
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*
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* Payload-to-userspace:
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* None.
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* Payload-to-kernel:
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* Character string containing STATUSTYPE_INFO
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*
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* When the request has been processed, user-space must return the
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* dm_ulog_request to the kernel - setting the 'error' field and
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* 'data_size' appropriately.
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*/
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#define DM_ULOG_STATUS_INFO 15
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/*
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* DM_ULOG_STATUS_TABLE corresponds to (found in dm-dirty-log.h):
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* int (*status)(struct dm_dirty_log *log, STATUSTYPE_TABLE,
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* char *result, unsigned maxlen);
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*
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* Payload-to-userspace:
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* None.
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* Payload-to-kernel:
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* Character string containing STATUSTYPE_TABLE
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*
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* When the request has been processed, user-space must return the
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* dm_ulog_request to the kernel - setting the 'error' field and
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* 'data_size' appropriately.
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*/
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#define DM_ULOG_STATUS_TABLE 16
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/*
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* DM_ULOG_IS_REMOTE_RECOVERING corresponds to (found in dm-dirty-log.h):
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* int (*is_remote_recovering)(struct dm_dirty_log *log, region_t region);
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*
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* Payload-to-userspace:
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* __u64 - region to determine recovery status on
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* Payload-to-kernel:
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* {
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* __s64 is_recovering; -- 0 if no, 1 if yes
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* __u64 in_sync_hint; -- lowest region still needing resync
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* }
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*
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* When the request has been processed, user-space must return the
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* dm_ulog_request to the kernel - setting the 'error' field and
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* 'data_size' appropriately.
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*/
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#define DM_ULOG_IS_REMOTE_RECOVERING 17
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/*
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* (DM_ULOG_REQUEST_MASK & request_type) to get the request type
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*
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* Payload-to-userspace:
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* A single string containing all the argv arguments separated by ' 's
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* Payload-to-kernel:
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* None. ('data_size' in the dm_ulog_request struct should be 0.)
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*
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* We are reserving 8 bits of the 32-bit 'request_type' field for the
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* various request types above. The remaining 24-bits are currently
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* set to zero and are reserved for future use and compatibility concerns.
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*
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* User-space should always use DM_ULOG_REQUEST_TYPE to acquire the
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* request type from the 'request_type' field to maintain forward compatibility.
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*/
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#define DM_ULOG_REQUEST_MASK 0xFF
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#define DM_ULOG_REQUEST_TYPE(request_type) \
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(DM_ULOG_REQUEST_MASK & (request_type))
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/*
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* DM_ULOG_REQUEST_VERSION is incremented when there is a
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* change to the way information is passed between kernel
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* and userspace. This could be a structure change of
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* dm_ulog_request or a change in the way requests are
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* issued/handled. Changes are outlined here:
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* version 1: Initial implementation
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* version 2: DM_ULOG_CTR allowed to return a string containing a
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* device name that is to be registered with DM via
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* 'dm_get_device'.
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* version 3: DM_ULOG_FLUSH is capable of carrying payload for marking
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* regions. This "integrated flush" reduces the number of
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* requests between the kernel and userspace by effectively
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* merging 'mark' and 'flush' requests. A constructor table
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* argument ('integrated_flush') is required to turn this
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* feature on, so it is backwards compatible with older
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* userspace versions.
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*/
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#define DM_ULOG_REQUEST_VERSION 3
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struct dm_ulog_request {
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/*
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* The local unique identifier (luid) and the universally unique
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* identifier (uuid) are used to tie a request to a specific
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* mirror log. A single machine log could probably make due with
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* just the 'luid', but a cluster-aware log must use the 'uuid' and
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* the 'luid'. The uuid is what is required for node to node
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* communication concerning a particular log, but the 'luid' helps
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* differentiate between logs that are being swapped and have the
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* same 'uuid'. (Think "live" and "inactive" device-mapper tables.)
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*/
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__u64 luid;
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char uuid[DM_UUID_LEN];
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char padding[3]; /* Padding because DM_UUID_LEN = 129 */
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__u32 version; /* See DM_ULOG_REQUEST_VERSION */
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__s32 error; /* Used to report back processing errors */
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__u32 seq; /* Sequence number for request */
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__u32 request_type; /* DM_ULOG_* defined above */
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__u32 data_size; /* How much data (not including this struct) */
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char data[];
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};
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#endif /* __DM_LOG_USERSPACE_H__ */
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