/*
* Copyright (C) 2001 - 2003 Sistina Software (UK) Limited.
* Copyright (C) 2004 - 2009 Red Hat, Inc. All rights reserved.
*
* This file is released under the LGPL.
*/
/*
* A traditional ioctl interface for the device mapper.
*
* Each device can have two tables associated with it, an
* 'active' table which is the one currently used by io passing
* through the device, and an 'inactive' one which is a table
* that is being prepared as a replacement for the 'active' one.
*
* DM_VERSION:
* Just get the version information for the ioctl interface.
*
* DM_REMOVE_ALL:
* Remove all dm devices, destroy all tables. Only really used
* for debug.
*
* DM_LIST_DEVICES:
* Get a list of all the dm device names.
*
* DM_DEV_CREATE:
* Create a new device, neither the 'active' or 'inactive' table
* slots will be filled. The device will be in suspended state
* after creation, however any io to the device will get errored
* since it will be out-of-bounds.
*
* DM_DEV_REMOVE:
* Remove a device, destroy any tables.
*
* DM_DEV_RENAME:
* Rename a device.
*
* DM_SUSPEND:
* This performs both suspend and resume, depending which flag is
* passed in.
* Suspend: This command will not return until all pending io to
* the device has completed. Further io will be deferred until
* the device is resumed.
* Resume: It is no longer an error to issue this command on an
* unsuspended device. If a table is present in the 'inactive'
* slot, it will be moved to the active slot, then the old table
* from the active slot will be _destroyed_. Finally the device
* is resumed.
*
* DM_DEV_STATUS:
* Retrieves the status for the table in the 'active' slot.
*
* DM_DEV_WAIT:
* Wait for a significant event to occur to the device. This
* could either be caused by an event triggered by one of the
* targets of the table in the 'active' slot, or a table change.
*
* DM_TABLE_LOAD:
* Load a table into the 'inactive' slot for the device. The
* device does _not_ need to be suspended prior to this command.
*
* DM_TABLE_CLEAR:
* Destroy any table in the 'inactive' slot (ie. abort).
*
* DM_TABLE_DEPS:
* Return a set of device dependencies for the 'active' table.
*
* DM_TABLE_STATUS:
* Return the targets status for the 'active' table.
*
* DM_TARGET_MSG:
* Pass a message string to the target at a specific offset of a device.
*
* DM_DEV_SET_GEOMETRY:
* Set the geometry of a device by passing in a string in this format:
*
* "cylinders heads sectors_per_track start_sector"
*
* Beware that CHS geometry is nearly obsolete and only provided
* for compatibility with dm devices that can be booted by a PC
* BIOS. See struct hd_geometry for range limits. Also note that
* the geometry is erased if the device size changes.
*/
/*
* All ioctl arguments consist of a single chunk of memory, with
* this structure at the start. If a uuid is specified any
* lookup (eg. for a DM_INFO) will be done on that, *not* the
* name.
*/
struct dm_ioctl {
/*
* The version number is made up of three parts:
* major - no backward or forward compatibility,
* minor - only backwards compatible,
* patch - both backwards and forwards compatible.
*
* All clients of the ioctl interface should fill in the
* version number of the interface that they were
* compiled with.
*
* All recognised ioctl commands (ie. those that don't
* return -ENOTTY) fill out this field, even if the
* command failed.
*/
uint32_t version[3]; /* in/out */
uint32_t data_size; /* total size of data passed in
* including this struct */
uint32_t data_start; /* offset to start of data
* relative to start of this struct */
/*
* event_nr holds either the event number (input and output) or the
* udev cookie value (input only).
* The DM_DEV_WAIT ioctl takes an event number as input.
* The DM_SUSPEND, DM_DEV_REMOVE and DM_DEV_RENAME ioctls
* use the field as a cookie to return in the DM_COOKIE
* variable with the uevents they issue.
* For output, the ioctls return the event number, not the cookie.
*/
uint32_t event_nr; /* in/out */
uint32_t padding;
uint64_t dev; /* in/out */
char name[DM_NAME_LEN]; /* device name */
char uuid[DM_UUID_LEN]; /* unique identifier for
* the block device */
char data[7]; /* padding or data */
};
/*
* Used to specify tables. These structures appear after the
* dm_ioctl.
*/
struct dm_target_spec {
uint64_t sector_start;
uint64_t length;
int32_t status; /* used when reading from kernel only */
/*
* Location of the next dm_target_spec.
* - When specifying targets on a DM_TABLE_LOAD command, this value is
* the number of bytes from the start of the "current" dm_target_spec
* to the start of the "next" dm_target_spec.
* - When retrieving targets on a DM_TABLE_STATUS command, this value
* is the number of bytes from the start of the first dm_target_spec
* (that follows the dm_ioctl struct) to the start of the "next"
* dm_target_spec.
*/
uint32_t next;
char target_type[DM_MAX_TYPE_NAME];
/*
* Parameter string starts immediately after this object.
* Be careful to add padding after string to ensure correct
* alignment of subsequent dm_target_spec.
*/
};
/*
* Used to retrieve the target dependencies.
*/
struct dm_target_deps {
uint32_t count; /* Array size */
uint32_t padding; /* unused */
uint64_t dev[0]; /* out */
};
/*
* Used to get a list of all dm devices.
*/
struct dm_name_list {
uint64_t dev;
uint32_t next; /* offset to the next record from
the _start_ of this */
char name[0];
};
/*
* Used to retrieve the target versions
*/
struct dm_target_versions {
uint32_t next;
uint32_t version[3];
char name[0];
};
/*
* Used to pass message to a target
*/
struct dm_target_msg {
uint64_t sector; /* Device sector */
char message[0];
};
/*
* If you change this make sure you make the corresponding change
* to dm-ioctl.c:lookup_ioctl()
*/
enum {
/* Top level cmds */
DM_VERSION_CMD = 0,
DM_REMOVE_ALL_CMD,
DM_LIST_DEVICES_CMD,
/*
* Flag passed into ioctl STATUS command to get table information
* rather than current status.
*/
#define DM_STATUS_TABLE_FLAG (1 << 4) /* In */
/*
* Flags that indicate whether a table is present in either of
* the two table slots that a device has.
*/
#define DM_ACTIVE_PRESENT_FLAG (1 << 5) /* Out */
#define DM_INACTIVE_PRESENT_FLAG (1 << 6) /* Out */
/*
* Indicates that the buffer passed in wasn't big enough for the
* results.
*/
#define DM_BUFFER_FULL_FLAG (1 << 8) /* Out */
/*
* This flag is now ignored.
*/
#define DM_SKIP_BDGET_FLAG (1 << 9) /* In */
/*
* Set this to avoid attempting to freeze any filesystem when suspending.
*/
#define DM_SKIP_LOCKFS_FLAG (1 << 10) /* In */
/*
* Set this to suspend without flushing queued ios.
*/
#define DM_NOFLUSH_FLAG (1 << 11) /* In */
/*
* If set, any table information returned will relate to the inactive
* table instead of the live one. Always check DM_INACTIVE_PRESENT_FLAG
* is set before using the data returned.
*/
#define DM_QUERY_INACTIVE_TABLE_FLAG (1 << 12) /* In */
