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432 lines
15 KiB
432 lines
15 KiB
/* 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[0]; |
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}; |
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#endif /* __DM_LOG_USERSPACE_H__ */
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