dm-ioctl.h

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/*
 * 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.
 */

#ifndef _LINUX_DM_IOCTL_V4_H
#define _LINUX_DM_IOCTL_V4_H

#include <linux/types.h>

#define DM_DIR "mapper"     /* Slashes not supported */
#define DM_CONTROL_NODE "control"
#define DM_MAX_TYPE_NAME 16
#define DM_NAME_LEN 128
#define DM_UUID_LEN 129

/*
 * 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 or set its uuid if none was previously supplied.
 *
 * 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.
     */
    __u32 version[3];   /* in/out */
    __u32 data_size;    /* total size of data passed in
                 * including this struct */

    __u32 data_start;   /* offset to start of data
                 * relative to start of this struct */

    __u32 target_count; /* in/out */
    __s32 open_count;   /* out */
    __u32 flags;        /* in/out */

    /*
     * 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.
     */
    __u32 event_nr;         /* in/out */
    __u32 padding;

    __u64 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 {
    __u64 sector_start;
    __u64 length;
    __s32 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.
     */
    __u32 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 {
    __u32 count;    /* Array size */
    __u32 padding;  /* unused */
    __u64 dev[0];   /* out */
};

/*
 * Used to get a list of all dm devices.
 */
struct dm_name_list {
    __u64 dev;
    __u32 next;     /* offset to the next record from
                   the _start_ of this */
    char name[0];
};

/*
 * Used to retrieve the target versions
 */
struct dm_target_versions {
        __u32 next;
        __u32 version[3];

        char name[0];
};

/*
 * Used to pass message to a target
 */
struct dm_target_msg {
    __u64 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,

    /* device level cmds */
    DM_DEV_CREATE_CMD,
    DM_DEV_REMOVE_CMD,
    DM_DEV_RENAME_CMD,
    DM_DEV_SUSPEND_CMD,
    DM_DEV_STATUS_CMD,
    DM_DEV_WAIT_CMD,

    /* Table level cmds */
    DM_TABLE_LOAD_CMD,
    DM_TABLE_CLEAR_CMD,
    DM_TABLE_DEPS_CMD,
    DM_TABLE_STATUS_CMD,

    /* Added later */
    DM_LIST_VERSIONS_CMD,
    DM_TARGET_MSG_CMD,
    DM_DEV_SET_GEOMETRY_CMD
};

#define DM_IOCTL 0xfd

#define DM_VERSION       _IOWR(DM_IOCTL, DM_VERSION_CMD, struct dm_ioctl)
#define DM_REMOVE_ALL    _IOWR(DM_IOCTL, DM_REMOVE_ALL_CMD, struct dm_ioctl)
#define DM_LIST_DEVICES  _IOWR(DM_IOCTL, DM_LIST_DEVICES_CMD, struct dm_ioctl)

#define DM_DEV_CREATE    _IOWR(DM_IOCTL, DM_DEV_CREATE_CMD, struct dm_ioctl)
#define DM_DEV_REMOVE    _IOWR(DM_IOCTL, DM_DEV_REMOVE_CMD, struct dm_ioctl)
#define DM_DEV_RENAME    _IOWR(DM_IOCTL, DM_DEV_RENAME_CMD, struct dm_ioctl)
#define DM_DEV_SUSPEND   _IOWR(DM_IOCTL, DM_DEV_SUSPEND_CMD, struct dm_ioctl)
#define DM_DEV_STATUS    _IOWR(DM_IOCTL, DM_DEV_STATUS_CMD, struct dm_ioctl)
#define DM_DEV_WAIT      _IOWR(DM_IOCTL, DM_DEV_WAIT_CMD, struct dm_ioctl)

#define DM_TABLE_LOAD    _IOWR(DM_IOCTL, DM_TABLE_LOAD_CMD, struct dm_ioctl)
#define DM_TABLE_CLEAR   _IOWR(DM_IOCTL, DM_TABLE_CLEAR_CMD, struct dm_ioctl)
#define DM_TABLE_DEPS    _IOWR(DM_IOCTL, DM_TABLE_DEPS_CMD, struct dm_ioctl)
#define DM_TABLE_STATUS  _IOWR(DM_IOCTL, DM_TABLE_STATUS_CMD, struct dm_ioctl)

#define DM_LIST_VERSIONS _IOWR(DM_IOCTL, DM_LIST_VERSIONS_CMD, struct dm_ioctl)

#define DM_TARGET_MSG    _IOWR(DM_IOCTL, DM_TARGET_MSG_CMD, struct dm_ioctl)
#define DM_DEV_SET_GEOMETRY _IOWR(DM_IOCTL, DM_DEV_SET_GEOMETRY_CMD, struct dm_ioctl)

#define DM_VERSION_MAJOR    4
#define DM_VERSION_MINOR    23
#define DM_VERSION_PATCHLEVEL   0
#define DM_VERSION_EXTRA    "-ioctl (2012-07-25)"

/* Status bits */
#define DM_READONLY_FLAG    (1 << 0) /* In/Out */
#define DM_SUSPEND_FLAG     (1 << 1) /* In/Out */
#define DM_PERSISTENT_DEV_FLAG  (1 << 3) /* In */

/*
 * 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.
 * Also disables flushing uncommitted changes in the thin target before
 * generating statistics for DM_TABLE_STATUS and DM_DEV_WAIT.
 */
#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 */

/*
 * If set, a uevent was generated for which the caller may need to wait.
 */
#define DM_UEVENT_GENERATED_FLAG    (1 << 13) /* Out */

/*
 * If set, rename changes the uuid not the name.  Only permitted
 * if no uuid was previously supplied: an existing uuid cannot be changed.
 */
#define DM_UUID_FLAG            (1 << 14) /* In */

/*
 * If set, all buffers are wiped after use. Use when sending
 * or requesting sensitive data such as an encryption key.
 */
#define DM_SECURE_DATA_FLAG     (1 << 15) /* In */

#endif              /* _LINUX_DM_IOCTL_H */