Current File : //var/lib/dkms/blksnap/6.3.0.73/source/blk_snap.h
/* SPDX-License-Identifier: GPL-2.0 */
#ifndef __LINUX_BLK_SNAP_H
#define __LINUX_BLK_SNAP_H
#include <linux/types.h>
#include <linux/uuid.h>
#define BLK_SNAP_MODULE_NAME "veeamblksnap"
#define BLK_SNAP_IMAGE_NAME "veeamblksnapimg"
#define BLK_SNAP 'V'
#ifdef BLK_SNAP_MODIFICATION
#define IOCTL_MOD 32
#endif
enum blk_snap_ioctl {
/*
* Service controls
*/
blk_snap_ioctl_version,
/*
* Contols for tracking
*/
blk_snap_ioctl_tracker_remove,
blk_snap_ioctl_tracker_collect,
blk_snap_ioctl_tracker_read_cbt_map,
blk_snap_ioctl_tracker_mark_dirty_blocks,
/*
* Snapshot contols
*/
blk_snap_ioctl_snapshot_create,
blk_snap_ioctl_snapshot_destroy,
blk_snap_ioctl_snapshot_append_storage,
blk_snap_ioctl_snapshot_take,
blk_snap_ioctl_snapshot_collect,
blk_snap_ioctl_snapshot_collect_images,
blk_snap_ioctl_snapshot_wait_event,
blk_snap_ioctl_end,
#ifdef BLK_SNAP_MODIFICATION
/*
* Additional controls for any standalone modification
*/
blk_snap_ioctl_mod = IOCTL_MOD,
blk_snap_ioctl_setlog,
blk_snap_ioctl_get_sector_state,
blk_snap_ioctl_end_mod
#endif
};
/**
* struct blk_snap_version - Result for the &IOCTL_BLK_SNAP_VERSION control.
* @major:
* Version major part.
* @minor:
* Version minor part.
* @revision:
* Revision number.
* @build:
* Build number. Should be zero.
*/
struct blk_snap_version {
__u16 major;
__u16 minor;
__u16 revision;
__u16 build;
};
/**
* IOCTL_BLK_SNAP_VERSION - Get version and compatibility flags.
*
* Linking the product behavior to the version code does not seem to be a very
* good idea. Version is only for logs.
*/
#define IOCTL_BLK_SNAP_VERSION \
_IOW(BLK_SNAP, blk_snap_ioctl_version, struct blk_snap_version)
#ifdef BLK_SNAP_MODIFICATION
enum blk_snap_compat_flags {
blk_snap_compat_flag_debug_sector_state,
blk_snap_compat_flag_setlog,
/*
* Reserved for new features
*/
blk_snap_compat_flags_end
};
static_assert(blk_snap_compat_flags_end <= 64,
"There are too many compatibility flags.");
#define BLK_SNAP_MOD_NAME_LIMIT 32
/**
* struct blk_snap_modification - Result for &IOCTL_BLK_SNAP_VERSION control.
*
* @compatibility_flags:
* [TBD] Reserved for new modification specific features.
* @name:
* Name of modification of the module (fork name, for example).
* It's should be empty string for upstream module.
*/
struct blk_snap_mod {
__u64 compatibility_flags;
__u8 name[BLK_SNAP_MOD_NAME_LIMIT];
};
/**
* IOCTL_BLK_SNAP_MOD - Get modification name and compatibility flags.
*
* Linking the product behavior to the version code does not seem to me a very
* good idea. However, such an ioctl is good for checking that the module has
* loaded and is responding to requests.
*
* The compatibility flags allows to safely extend the functionality of the
* module. When the blk_snap kernel module receives new ioctl it will be
* enough to add a bit.
*
* The name of the modification can be used by the authors of forks and branches
* of the original module. The module in upstream have not any modifications.
*/
#define IOCTL_BLK_SNAP_MOD \
_IOW(BLK_SNAP, blk_snap_ioctl_mod, struct blk_snap_mod)
#endif
/*
* The main functionality of the module is change block tracking (CBT).
* Next, a number of ioctls will describe the interface for the CBT mechanism.
*/
/**
* struct blk_snap_dev_t - Block device ID.
* @mj:
* Device ID major part.
* @mn:
* Device ID minor part.
*
* In user space and in kernel space, block devices are encoded differently.
* We need to enter our own type to guarantee the correct transmission of the
* major and minor parts.
*/
struct blk_snap_dev_t {
__u32 mj;
__u32 mn;
};
/**
* struct blk_snap_tracker_remove - Input argument for the
* &IOCTL_BLK_SNAP_TRACKER_REMOVE control.
* @dev_id:
* Device ID.
*/
struct blk_snap_tracker_remove {
struct blk_snap_dev_t dev_id;
};
/**
* IOCTL_BLK_SNAP_TRACKER_REMOVE - Remove a device from tracking.
*
* Removes the device from tracking changes.
* Adding a device for tracking is performed when creating a snapshot
* that includes this device.
*/
#define IOCTL_BLK_SNAP_TRACKER_REMOVE \
_IOW(BLK_SNAP, blk_snap_ioctl_tracker_remove, \
struct blk_snap_tracker_remove)
/**
* struct blk_snap_cbt_info - Information about change tracking for a block
* device.
* @dev_id:
* Device ID.
* @blk_size:
* Block size in bytes.
* @device_capacity:
* Device capacity in bytes.
* @blk_count:
* Number of blocks.
* @generation_id:
* Unique identification number of change tracking generation.
* @snap_number:
* Current changes number.
*/
struct blk_snap_cbt_info {
struct blk_snap_dev_t dev_id;
__u32 blk_size;
__u64 device_capacity;
__u32 blk_count;
uuid_t generation_id;
__u8 snap_number;
};
/**
* struct blk_snap_tracker_collect - Argument for the
* &IOCTL_BLK_SNAP_TRACKER_COLLECT control.
* @count:
* Size of @cbt_info_array in the number of &struct blk_snap_cbt_info.
* If @cbt_info_array has not enough space, it will contain the required
* size of the array.
* @cbt_info_array:
* Pointer to the array for output.
*/
struct blk_snap_tracker_collect {
__u32 count;
struct blk_snap_cbt_info *cbt_info_array;
};
/**
* IOCTL_BLK_SNAP_TRACKER_COLLECT - Collect all tracked devices.
*
* Getting information about all devices under tracking.
* This ioctl returns the same information that the module outputs
* to sysfs for each device under tracking.
*/
#define IOCTL_BLK_SNAP_TRACKER_COLLECT \
_IOW(BLK_SNAP, blk_snap_ioctl_tracker_collect, \
struct blk_snap_tracker_collect)
/**
* struct blk_snap_tracker_read_cbt_bitmap - Argument for the
* &IOCTL_BLK_SNAP_TRACKER_READ_CBT_MAP control.
* @dev_id:
* Device ID.
* @offset:
* Offset from the beginning of the CBT bitmap in bytes.
* @length:
* Size of @buff in bytes.
* @buff:
* Pointer to the buffer for output.
*/
struct blk_snap_tracker_read_cbt_bitmap {
struct blk_snap_dev_t dev_id;
__u32 offset;
__u32 length;
__u8 *buff;
};
/**
* IOCTL_BLK_SNAP_TRACKER_READ_CBT_MAP - Read the CBT map.
*
* This ioctl allows to read the table of changes. Sysfs also has a file that
* allows to read this table.
*/
#define IOCTL_BLK_SNAP_TRACKER_READ_CBT_MAP \
_IOR(BLK_SNAP, blk_snap_ioctl_tracker_read_cbt_map, \
struct blk_snap_tracker_read_cbt_bitmap)
/**
* struct blk_snap_block_range - Element of array for
* &struct blk_snap_tracker_mark_dirty_blocks.
* @sector_offset:
* Offset from the beginning of the disk in sectors.
* @sector_count:
* Number of sectors.
*/
struct blk_snap_block_range {
__u64 sector_offset;
__u64 sector_count;
};
/**
* struct blk_snap_tracker_mark_dirty_blocks - Argument for the
* &IOCTL_BLK_SNAP_TRACKER_MARK_DIRTY_BLOCKS control.
* @dev_id:
* Device ID.
* @count:
* Size of @dirty_blocks_array in the number of
* &struct blk_snap_block_range.
* @dirty_blocks_array:
* Pointer to the array of &struct blk_snap_block_range.
*/
struct blk_snap_tracker_mark_dirty_blocks {
struct blk_snap_dev_t dev_id;
__u32 count;
struct blk_snap_block_range *dirty_blocks_array;
};
/**
* IOCTL_BLK_SNAP_TRACKER_MARK_DIRTY_BLOCKS - Set dirty blocks in the CBT map.
*
* There are cases when some blocks need to be marked as changed.
* This ioctl allows to do this.
*/
#define IOCTL_BLK_SNAP_TRACKER_MARK_DIRTY_BLOCKS \
_IOR(BLK_SNAP, blk_snap_ioctl_tracker_mark_dirty_blocks, \
struct blk_snap_tracker_mark_dirty_blocks)
/*
* Next, there will be a description of the interface for working with
* snapshots.
*/
/**
* struct blk_snap_snapshot_create - Argument for the
* &IOCTL_BLK_SNAP_SNAPSHOT_CREATE control.
* @count:
* Size of @dev_id_array in the number of &struct blk_snap_dev_t.
* @dev_id_array:
* Pointer to the array of &struct blk_snap_dev_t.
* @id:
* Return ID of the created snapshot.
*/
struct blk_snap_snapshot_create {
__u32 count;
struct blk_snap_dev_t *dev_id_array;
uuid_t id;
};
/**
* This ioctl creates a snapshot structure in the memory and allocates an
* identifier for it. Further interaction with the snapshot is possible by
* this identifier.
* Several snapshots can be created at the same time, but with the condition
* that one block device can only be included in one snapshot.
*/
#define IOCTL_BLK_SNAP_SNAPSHOT_CREATE \
_IOW(BLK_SNAP, blk_snap_ioctl_snapshot_create, \
struct blk_snap_snapshot_create)
/**
* struct blk_snap_snapshot_destroy - Argument for the
* &IOCTL_BLK_SNAP_SNAPSHOT_DESTROY control.
* @id:
* Snapshot ID.
*/
struct blk_snap_snapshot_destroy {
uuid_t id;
};
/**
* IOCTL_BLK_SNAP_SNAPSHOT_DESTROY - Release and destroy the snapshot.
*
* Destroys all snapshot structures and releases all its allocated resources.
*/
#define IOCTL_BLK_SNAP_SNAPSHOT_DESTROY \
_IOR(BLK_SNAP, blk_snap_ioctl_snapshot_destroy, \
struct blk_snap_snapshot_destroy)
/**
* struct blk_snap_snapshot_append_storage - Argument for the
* &IOCTL_BLK_SNAP_SNAPSHOT_APPEND_STORAGE control.
* @id:
* Snapshot ID.
* @dev_id:
* Device ID.
* @count:
* Size of @ranges in the number of &struct blk_snap_block_range.
* @ranges:
* Pointer to the array of &struct blk_snap_block_range.
*/
struct blk_snap_snapshot_append_storage {
uuid_t id;
struct blk_snap_dev_t dev_id;
__u32 count;
struct blk_snap_block_range *ranges;
};
/**
* IOCTL_BLK_SNAP_SNAPSHOT_APPEND_STORAGE - Append storage to the difference
* storage of the snapshot.
*
* The snapshot difference storage can be set either before or after creating
* the snapshot images. This allows to dynamically expand the difference
* storage while holding the snapshot.
*/
#define IOCTL_BLK_SNAP_SNAPSHOT_APPEND_STORAGE \
_IOW(BLK_SNAP, blk_snap_ioctl_snapshot_append_storage, \
struct blk_snap_snapshot_append_storage)
/**
* struct blk_snap_snapshot_take - Argument for the
* &IOCTL_BLK_SNAP_SNAPSHOT_TAKE control.
* @id:
* Snapshot ID.
*/
struct blk_snap_snapshot_take {
uuid_t id;
};
/**
* IOCTL_BLK_SNAP_SNAPSHOT_TAKE - Take snapshot.
*
* This ioctl creates snapshot images of block devices and switches CBT tables.
* The snapshot must be created before this call, and the areas of block
* devices should be added to the difference storage.
*/
#define IOCTL_BLK_SNAP_SNAPSHOT_TAKE \
_IOR(BLK_SNAP, blk_snap_ioctl_snapshot_take, \
struct blk_snap_snapshot_take)
/**
* struct blk_snap_snapshot_collect - Argument for the
* &IOCTL_BLK_SNAP_SNAPSHOT_COLLECT control.
* @count:
* Size of @ids in the number of &uuid_t.
* If @ids has not enough space, it will contain the required
* size of the array.
* @ids:
* Pointer to the array with the snapshot ID for output. If the pointer is
* zero, the ioctl returns the number of active snapshots in &count.
*
*/
struct blk_snap_snapshot_collect {
__u32 count;
uuid_t *ids;
};
/**
* IOCTL_BLK_SNAP_SNAPSHOT_COLLECT - Get collection of created snapshots.
*
* This information can also be obtained from files from sysfs.
*/
#define IOCTL_BLK_SNAP_SNAPSHOT_COLLECT \
_IOW(BLK_SNAP, blk_snap_ioctl_snapshot_collect, \
struct blk_snap_snapshot_collect)
/**
* struct blk_snap_image_info - Associates the original device in the snapshot
* and the corresponding snapshot image.
* @orig_dev_id:
* Device ID.
* @image_dev_id:
* Image ID.
*/
struct blk_snap_image_info {
struct blk_snap_dev_t orig_dev_id;
struct blk_snap_dev_t image_dev_id;
};
/**
* struct blk_snap_snapshot_collect_images - Argument for the
* &IOCTL_BLK_SNAP_SNAPSHOT_COLLECT_IMAGES control.
* @id:
* Snapshot ID.
* @count:
* Size of @image_info_array in the number of &struct blk_snap_image_info.
* If @image_info_array has not enough space, it will contain the required
* size of the array.
* @image_info_array:
* Pointer to the array for output.
*/
struct blk_snap_snapshot_collect_images {
uuid_t id;
__u32 count;
struct blk_snap_image_info *image_info_array;
};
/**
* IOCTL_BLK_SNAP_SNAPSHOT_COLLECT_IMAGES - Get a collection of devices and
* their snapshot images.
*
* While holding the snapshot, this ioctl allows you to get a table of
* correspondences of the original devices and their snapshot images.
* This information can also be obtained from files from sysfs.
*/
#define IOCTL_BLK_SNAP_SNAPSHOT_COLLECT_IMAGES \
_IOW(BLK_SNAP, blk_snap_ioctl_snapshot_collect_images, \
struct blk_snap_snapshot_collect_images)
enum blk_snap_event_codes {
/**
* Low free space in difference storage event.
*
* If the free space in the difference storage is reduced to the
* specified limit, the module generates this event.
*/
blk_snap_event_code_low_free_space,
/**
* Snapshot image is corrupted event.
*
* If a chunk could not be allocated when trying to save data to the
* difference storage, this event is generated.
* However, this does not mean that the backup process was interrupted
* with an error. If the snapshot image has been read to the end by
* this time, the backup process is considered successful.
*/
blk_snap_event_code_corrupted,
};
/**
* struct blk_snap_snapshot_event - Argument for the
* &IOCTL_BLK_SNAP_SNAPSHOT_WAIT_EVENT control.
* @id:
* Snapshot ID.
* @timeout_ms:
* Timeout for waiting in milliseconds.
* @time_label:
* Timestamp of the received event.
* @code:
* Code of the received event.
* @data:
* The received event body.
*/
struct blk_snap_snapshot_event {
uuid_t id;
__u32 timeout_ms;
__u32 code;
__s64 time_label;
__u8 data[4096 - 32];
};
static_assert(
sizeof(struct blk_snap_snapshot_event) == 4096,
"The size struct blk_snap_snapshot_event should be equal to the size of the page.");
/**
* IOCTL_BLK_SNAP_SNAPSHOT_WAIT_EVENT - Wait and get the event from the
* snapshot.
*
* While holding the snapshot, the kernel module can transmit information about
* changes in its state in the form of events to the user level.
* It is very important to receive these events as quickly as possible, so the
* user's thread is in the state of interruptable sleep.
*/
#define IOCTL_BLK_SNAP_SNAPSHOT_WAIT_EVENT \
_IOW(BLK_SNAP, blk_snap_ioctl_snapshot_wait_event, \
struct blk_snap_snapshot_event)
/**
* struct blk_snap_event_low_free_space - Data for the
* &blk_snap_event_code_low_free_space event.
* @requested_nr_sect:
* The required number of sectors.
*/
struct blk_snap_event_low_free_space {
__u64 requested_nr_sect;
};
/**
* struct blk_snap_event_corrupted - Data for the
* &blk_snap_event_code_corrupted event.
* @orig_dev_id:
* Device ID.
* @err_code:
* Error code.
*/
struct blk_snap_event_corrupted {
struct blk_snap_dev_t orig_dev_id;
__s32 err_code;
};
#ifdef BLK_SNAP_MODIFICATION
/**
* @tz_minuteswest:
* Time zone offset in minutes.
* The system time is in UTC. In order for the module to write local time
* to the log, its offset should be specified.
* @level:
* 0 - disable logging to file
* 3 - only error messages
* 4 - log warnings
* 6 - log info messages
* 7 - log debug messages
* @filepath_size:
* Count of bytes in &filepath.
* @filename:
* Full path for log file.
*/
struct blk_snap_setlog {
__s32 tz_minuteswest;
__u32 level;
__u32 filepath_size;
__u8 *filepath;
};
/**
*
*/
#define IOCTL_BLK_SNAP_SETLOG \
_IOW(BLK_SNAP, blk_snap_ioctl_setlog, struct blk_snap_setlog)
/**
*
*/
struct blk_snap_sector_state {
__u8 snap_number_prev;
__u8 snap_number_curr;
__u32 chunk_state;
};
struct blk_snap_get_sector_state {
struct blk_snap_dev_t image_dev_id;
__u64 sector;
struct blk_snap_sector_state state;
};
/**
*
*/
#define IOCTL_BLK_SNAP_GET_SECTOR_STATE \
_IOW(BLK_SNAP, blk_snap_ioctl_get_sector_state, \
struct blk_snap_get_sector_state)
#endif /* BLK_SNAP_MODIFICATION */
#endif /* __LINUX_BLK_SNAP_H */
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