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![Milan Broz](/assets/img/avatar_default.png)
Add support for passing a 32 bit "cookie" into the kernel with the DM_SUSPEND, DM_DEV_RENAME and DM_DEV_REMOVE ioctls. The (unsigned) value of this cookie is returned to userspace alongside the uevents issued by these ioctls in the variable DM_COOKIE. This means the userspace process issuing these ioctls can be notified by udev after udev has completed any actions triggered. To minimise the interface extension, we pass the cookie into the kernel in the event_nr field which is otherwise unused when calling these ioctls. Incrementing the version number allows userspace to determine in advance whether or not the kernel supports the cookie. If the kernel does support this but userspace does not, there should be no impact as the new variable will just get ignored. Signed-off-by: Milan Broz <mbroz@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
312 lines
8.9 KiB
C
312 lines
8.9 KiB
C
/*
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* Copyright (C) 2001 - 2003 Sistina Software (UK) Limited.
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* Copyright (C) 2004 - 2005 Red Hat, Inc. All rights reserved.
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*
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* This file is released under the LGPL.
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*/
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#ifndef _LINUX_DM_IOCTL_V4_H
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#define _LINUX_DM_IOCTL_V4_H
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#include <linux/types.h>
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#define DM_DIR "mapper" /* Slashes not supported */
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#define DM_MAX_TYPE_NAME 16
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#define DM_NAME_LEN 128
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#define DM_UUID_LEN 129
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/*
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* A traditional ioctl interface for the device mapper.
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*
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* Each device can have two tables associated with it, an
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* 'active' table which is the one currently used by io passing
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* through the device, and an 'inactive' one which is a table
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* that is being prepared as a replacement for the 'active' one.
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*
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* DM_VERSION:
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* Just get the version information for the ioctl interface.
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*
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* DM_REMOVE_ALL:
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* Remove all dm devices, destroy all tables. Only really used
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* for debug.
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*
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* DM_LIST_DEVICES:
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* Get a list of all the dm device names.
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*
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* DM_DEV_CREATE:
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* Create a new device, neither the 'active' or 'inactive' table
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* slots will be filled. The device will be in suspended state
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* after creation, however any io to the device will get errored
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* since it will be out-of-bounds.
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*
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* DM_DEV_REMOVE:
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* Remove a device, destroy any tables.
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*
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* DM_DEV_RENAME:
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* Rename a device.
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*
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* DM_SUSPEND:
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* This performs both suspend and resume, depending which flag is
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* passed in.
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* Suspend: This command will not return until all pending io to
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* the device has completed. Further io will be deferred until
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* the device is resumed.
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* Resume: It is no longer an error to issue this command on an
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* unsuspended device. If a table is present in the 'inactive'
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* slot, it will be moved to the active slot, then the old table
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* from the active slot will be _destroyed_. Finally the device
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* is resumed.
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*
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* DM_DEV_STATUS:
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* Retrieves the status for the table in the 'active' slot.
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*
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* DM_DEV_WAIT:
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* Wait for a significant event to occur to the device. This
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* could either be caused by an event triggered by one of the
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* targets of the table in the 'active' slot, or a table change.
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*
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* DM_TABLE_LOAD:
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* Load a table into the 'inactive' slot for the device. The
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* device does _not_ need to be suspended prior to this command.
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*
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* DM_TABLE_CLEAR:
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* Destroy any table in the 'inactive' slot (ie. abort).
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*
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* DM_TABLE_DEPS:
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* Return a set of device dependencies for the 'active' table.
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*
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* DM_TABLE_STATUS:
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* Return the targets status for the 'active' table.
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*
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* DM_TARGET_MSG:
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* Pass a message string to the target at a specific offset of a device.
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*
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* DM_DEV_SET_GEOMETRY:
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* Set the geometry of a device by passing in a string in this format:
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*
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* "cylinders heads sectors_per_track start_sector"
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*
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* Beware that CHS geometry is nearly obsolete and only provided
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* for compatibility with dm devices that can be booted by a PC
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* BIOS. See struct hd_geometry for range limits. Also note that
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* the geometry is erased if the device size changes.
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*/
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/*
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* All ioctl arguments consist of a single chunk of memory, with
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* this structure at the start. If a uuid is specified any
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* lookup (eg. for a DM_INFO) will be done on that, *not* the
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* name.
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*/
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struct dm_ioctl {
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/*
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* The version number is made up of three parts:
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* major - no backward or forward compatibility,
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* minor - only backwards compatible,
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* patch - both backwards and forwards compatible.
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*
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* All clients of the ioctl interface should fill in the
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* version number of the interface that they were
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* compiled with.
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*
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* All recognised ioctl commands (ie. those that don't
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* return -ENOTTY) fill out this field, even if the
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* command failed.
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*/
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__u32 version[3]; /* in/out */
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__u32 data_size; /* total size of data passed in
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* including this struct */
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__u32 data_start; /* offset to start of data
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* relative to start of this struct */
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__u32 target_count; /* in/out */
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__s32 open_count; /* out */
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__u32 flags; /* in/out */
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/*
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* event_nr holds either the event number (input and output) or the
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* udev cookie value (input only).
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* The DM_DEV_WAIT ioctl takes an event number as input.
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* The DM_SUSPEND, DM_DEV_REMOVE and DM_DEV_RENAME ioctls
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* use the field as a cookie to return in the DM_COOKIE
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* variable with the uevents they issue.
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* For output, the ioctls return the event number, not the cookie.
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*/
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__u32 event_nr; /* in/out */
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__u32 padding;
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__u64 dev; /* in/out */
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char name[DM_NAME_LEN]; /* device name */
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char uuid[DM_UUID_LEN]; /* unique identifier for
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* the block device */
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char data[7]; /* padding or data */
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};
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/*
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* Used to specify tables. These structures appear after the
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* dm_ioctl.
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*/
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struct dm_target_spec {
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__u64 sector_start;
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__u64 length;
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__s32 status; /* used when reading from kernel only */
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/*
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* Location of the next dm_target_spec.
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* - When specifying targets on a DM_TABLE_LOAD command, this value is
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* the number of bytes from the start of the "current" dm_target_spec
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* to the start of the "next" dm_target_spec.
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* - When retrieving targets on a DM_TABLE_STATUS command, this value
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* is the number of bytes from the start of the first dm_target_spec
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* (that follows the dm_ioctl struct) to the start of the "next"
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* dm_target_spec.
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*/
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__u32 next;
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char target_type[DM_MAX_TYPE_NAME];
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/*
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* Parameter string starts immediately after this object.
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* Be careful to add padding after string to ensure correct
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* alignment of subsequent dm_target_spec.
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*/
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};
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/*
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* Used to retrieve the target dependencies.
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*/
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struct dm_target_deps {
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__u32 count; /* Array size */
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__u32 padding; /* unused */
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__u64 dev[0]; /* out */
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};
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/*
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* Used to get a list of all dm devices.
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*/
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struct dm_name_list {
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__u64 dev;
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__u32 next; /* offset to the next record from
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the _start_ of this */
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char name[0];
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};
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/*
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* Used to retrieve the target versions
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*/
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struct dm_target_versions {
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__u32 next;
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__u32 version[3];
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char name[0];
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};
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/*
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* Used to pass message to a target
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*/
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struct dm_target_msg {
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__u64 sector; /* Device sector */
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char message[0];
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};
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/*
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* If you change this make sure you make the corresponding change
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* to dm-ioctl.c:lookup_ioctl()
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*/
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enum {
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/* Top level cmds */
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DM_VERSION_CMD = 0,
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DM_REMOVE_ALL_CMD,
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DM_LIST_DEVICES_CMD,
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/* device level cmds */
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DM_DEV_CREATE_CMD,
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DM_DEV_REMOVE_CMD,
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DM_DEV_RENAME_CMD,
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DM_DEV_SUSPEND_CMD,
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DM_DEV_STATUS_CMD,
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DM_DEV_WAIT_CMD,
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/* Table level cmds */
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DM_TABLE_LOAD_CMD,
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DM_TABLE_CLEAR_CMD,
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DM_TABLE_DEPS_CMD,
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DM_TABLE_STATUS_CMD,
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/* Added later */
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DM_LIST_VERSIONS_CMD,
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DM_TARGET_MSG_CMD,
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DM_DEV_SET_GEOMETRY_CMD
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};
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#define DM_IOCTL 0xfd
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#define DM_VERSION _IOWR(DM_IOCTL, DM_VERSION_CMD, struct dm_ioctl)
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#define DM_REMOVE_ALL _IOWR(DM_IOCTL, DM_REMOVE_ALL_CMD, struct dm_ioctl)
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#define DM_LIST_DEVICES _IOWR(DM_IOCTL, DM_LIST_DEVICES_CMD, struct dm_ioctl)
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#define DM_DEV_CREATE _IOWR(DM_IOCTL, DM_DEV_CREATE_CMD, struct dm_ioctl)
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#define DM_DEV_REMOVE _IOWR(DM_IOCTL, DM_DEV_REMOVE_CMD, struct dm_ioctl)
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#define DM_DEV_RENAME _IOWR(DM_IOCTL, DM_DEV_RENAME_CMD, struct dm_ioctl)
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#define DM_DEV_SUSPEND _IOWR(DM_IOCTL, DM_DEV_SUSPEND_CMD, struct dm_ioctl)
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#define DM_DEV_STATUS _IOWR(DM_IOCTL, DM_DEV_STATUS_CMD, struct dm_ioctl)
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#define DM_DEV_WAIT _IOWR(DM_IOCTL, DM_DEV_WAIT_CMD, struct dm_ioctl)
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#define DM_TABLE_LOAD _IOWR(DM_IOCTL, DM_TABLE_LOAD_CMD, struct dm_ioctl)
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#define DM_TABLE_CLEAR _IOWR(DM_IOCTL, DM_TABLE_CLEAR_CMD, struct dm_ioctl)
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#define DM_TABLE_DEPS _IOWR(DM_IOCTL, DM_TABLE_DEPS_CMD, struct dm_ioctl)
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#define DM_TABLE_STATUS _IOWR(DM_IOCTL, DM_TABLE_STATUS_CMD, struct dm_ioctl)
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#define DM_LIST_VERSIONS _IOWR(DM_IOCTL, DM_LIST_VERSIONS_CMD, struct dm_ioctl)
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#define DM_TARGET_MSG _IOWR(DM_IOCTL, DM_TARGET_MSG_CMD, struct dm_ioctl)
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#define DM_DEV_SET_GEOMETRY _IOWR(DM_IOCTL, DM_DEV_SET_GEOMETRY_CMD, struct dm_ioctl)
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#define DM_VERSION_MAJOR 4
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#define DM_VERSION_MINOR 15
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#define DM_VERSION_PATCHLEVEL 0
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#define DM_VERSION_EXTRA "-ioctl (2009-04-01)"
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/* Status bits */
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#define DM_READONLY_FLAG (1 << 0) /* In/Out */
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#define DM_SUSPEND_FLAG (1 << 1) /* In/Out */
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#define DM_PERSISTENT_DEV_FLAG (1 << 3) /* In */
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/*
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* Flag passed into ioctl STATUS command to get table information
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* rather than current status.
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*/
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#define DM_STATUS_TABLE_FLAG (1 << 4) /* In */
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/*
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* Flags that indicate whether a table is present in either of
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* the two table slots that a device has.
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*/
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#define DM_ACTIVE_PRESENT_FLAG (1 << 5) /* Out */
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#define DM_INACTIVE_PRESENT_FLAG (1 << 6) /* Out */
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/*
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* Indicates that the buffer passed in wasn't big enough for the
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* results.
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*/
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#define DM_BUFFER_FULL_FLAG (1 << 8) /* Out */
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/*
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* This flag is now ignored.
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*/
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#define DM_SKIP_BDGET_FLAG (1 << 9) /* In */
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/*
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* Set this to avoid attempting to freeze any filesystem when suspending.
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*/
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#define DM_SKIP_LOCKFS_FLAG (1 << 10) /* In */
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/*
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* Set this to suspend without flushing queued ios.
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*/
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#define DM_NOFLUSH_FLAG (1 << 11) /* In */
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#endif /* _LINUX_DM_IOCTL_H */
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