include/linux/dm-ioctl.h

   1 /*
   2  * Copyright (C) 2001 - 2003 Sistina Software (UK) Limited.
   3  * Copyright (C) 2004 - 2009 Red Hat, Inc. All rights reserved.
   4  *
   5  * This file is released under the LGPL.
   6  */
   7
   8 #ifndef _LINUX_DM_IOCTL_V4_H
   9 #define _LINUX_DM_IOCTL_V4_H
  10
  11 #include <linux/types.h>
  12
  13 #define DM_DIR "mapper"         /* Slashes not supported */
  14 #define DM_CONTROL_NODE "control"
  15 #define DM_MAX_TYPE_NAME 16
  16 #define DM_NAME_LEN 128
  17 #define DM_UUID_LEN 129
  18
  19 /*
  20  * A traditional ioctl interface for the device mapper.
  21  *
  22  * Each device can have two tables associated with it, an
  23  * 'active' table which is the one currently used by io passing
  24  * through the device, and an 'inactive' one which is a table
  25  * that is being prepared as a replacement for the 'active' one.
  26  *
  27  * DM_VERSION:
  28  * Just get the version information for the ioctl interface.
  29  *
  30  * DM_REMOVE_ALL:
  31  * Remove all dm devices, destroy all tables.  Only really used
  32  * for debug.
  33  *
  34  * DM_LIST_DEVICES:
  35  * Get a list of all the dm device names.
  36  *
  37  * DM_DEV_CREATE:
  38  * Create a new device, neither the 'active' or 'inactive' table
  39  * slots will be filled.  The device will be in suspended state
  40  * after creation, however any io to the device will get errored
  41  * since it will be out-of-bounds.
  42  *
  43  * DM_DEV_REMOVE:
  44  * Remove a device, destroy any tables.
  45  *
  46  * DM_DEV_RENAME:
  47  * Rename a device or set its uuid if none was previously supplied.
  48  *
  49  * DM_SUSPEND:
  50  * This performs both suspend and resume, depending which flag is
  51  * passed in.
  52  * Suspend: This command will not return until all pending io to
  53  * the device has completed.  Further io will be deferred until
  54  * the device is resumed.
  55  * Resume: It is no longer an error to issue this command on an
  56  * unsuspended device.  If a table is present in the 'inactive'
  57  * slot, it will be moved to the active slot, then the old table
  58  * from the active slot will be _destroyed_.  Finally the device
  59  * is resumed.
  60  *
  61  * DM_DEV_STATUS:
  62  * Retrieves the status for the table in the 'active' slot.
  63  *
  64  * DM_DEV_WAIT:
  65  * Wait for a significant event to occur to the device.  This
  66  * could either be caused by an event triggered by one of the
  67  * targets of the table in the 'active' slot, or a table change.
  68  *
  69  * DM_TABLE_LOAD:
  70  * Load a table into the 'inactive' slot for the device.  The
  71  * device does _not_ need to be suspended prior to this command.
  72  *
  73  * DM_TABLE_CLEAR:
  74  * Destroy any table in the 'inactive' slot (ie. abort).
  75  *
  76  * DM_TABLE_DEPS:
  77  * Return a set of device dependencies for the 'active' table.
  78  *
  79  * DM_TABLE_STATUS:
  80  * Return the targets status for the 'active' table.
  81  *
  82  * DM_TARGET_MSG:
  83  * Pass a message string to the target at a specific offset of a device.
  84  *
  85  * DM_DEV_SET_GEOMETRY:
  86  * Set the geometry of a device by passing in a string in this format:
  87  *
  88  * "cylinders heads sectors_per_track start_sector"
  89  *
  90  * Beware that CHS geometry is nearly obsolete and only provided
  91  * for compatibility with dm devices that can be booted by a PC
  92  * BIOS.  See struct hd_geometry for range limits.  Also note that
  93  * the geometry is erased if the device size changes.
  94  */
  95
  96 /*
  97  * All ioctl arguments consist of a single chunk of memory, with
  98  * this structure at the start.  If a uuid is specified any
  99  * lookup (eg. for a DM_INFO) will be done on that, *not* the
 100  * name.
 101  */
 102 struct dm_ioctl {
 103         /*
 104          * The version number is made up of three parts:
 105          * major - no backward or forward compatibility,
 106          * minor - only backwards compatible,
 107          * patch - both backwards and forwards compatible.
 108          *
 109          * All clients of the ioctl interface should fill in the
 110          * version number of the interface that they were
 111          * compiled with.
 112          *
 113          * All recognised ioctl commands (ie. those that don't
 114          * return -ENOTTY) fill out this field, even if the
 115          * command failed.
 116          */
 117         __u32 version[3];       /* in/out */
 118         __u32 data_size;        /* total size of data passed in
 119                                  * including this struct */
 120
 121         __u32 data_start;       /* offset to start of data
 122                                  * relative to start of this struct */
 123
 124         __u32 target_count;     /* in/out */
 125         __s32 open_count;       /* out */
 126         __u32 flags;            /* in/out */
 127
 128         /*
 129          * event_nr holds either the event number (input and output) or the
 130          * udev cookie value (input only).
 131          * The DM_DEV_WAIT ioctl takes an event number as input.
 132          * The DM_SUSPEND, DM_DEV_REMOVE and DM_DEV_RENAME ioctls
 133          * use the field as a cookie to return in the DM_COOKIE
 134          * variable with the uevents they issue.
 135          * For output, the ioctls return the event number, not the cookie.
 136          */
 137         __u32 event_nr;         /* in/out */
 138         __u32 padding;
 139
 140         __u64 dev;              /* in/out */
 141
 142         char name[DM_NAME_LEN]; /* device name */
 143         char uuid[DM_UUID_LEN]; /* unique identifier for
 144                                  * the block device */
 145         char data[7];           /* padding or data */
 146 };
 147
 148 /*
 149  * Used to specify tables.  These structures appear after the
 150  * dm_ioctl.
 151  */
 152 struct dm_target_spec {
 153         __u64 sector_start;
 154         __u64 length;
 155         __s32 status;           /* used when reading from kernel only */
 156
 157         /*
 158          * Location of the next dm_target_spec.
 159          * - When specifying targets on a DM_TABLE_LOAD command, this value is
 160          *   the number of bytes from the start of the "current" dm_target_spec
 161          *   to the start of the "next" dm_target_spec.
 162          * - When retrieving targets on a DM_TABLE_STATUS command, this value
 163          *   is the number of bytes from the start of the first dm_target_spec
 164          *   (that follows the dm_ioctl struct) to the start of the "next"
 165          *   dm_target_spec.
 166          */
 167         __u32 next;
 168
 169         char target_type[DM_MAX_TYPE_NAME];
 170
 171         /*
 172          * Parameter string starts immediately after this object.
 173          * Be careful to add padding after string to ensure correct
 174          * alignment of subsequent dm_target_spec.
 175          */
 176 };
 177
 178 /*
 179  * Used to retrieve the target dependencies.
 180  */
 181 struct dm_target_deps {
 182         __u32 count;    /* Array size */
 183         __u32 padding;  /* unused */
 184         __u64 dev[0];   /* out */
 185 };
 186
 187 /*
 188  * Used to get a list of all dm devices.
 189  */
 190 struct dm_name_list {
 191         __u64 dev;
 192         __u32 next;             /* offset to the next record from
 193                                    the _start_ of this */
 194         char name[0];
 195 };
 196
 197 /*
 198  * Used to retrieve the target versions
 199  */
 200 struct dm_target_versions {
 201         __u32 next;
 202         __u32 version[3];
 203
 204         char name[0];
 205 };
 206
 207 /*
 208  * Used to pass message to a target
 209  */
 210 struct dm_target_msg {
 211         __u64 sector;   /* Device sector */
 212
 213         char message[0];
 214 };
 215
 216 /*
 217  * If you change this make sure you make the corresponding change
 218  * to dm-ioctl.c:lookup_ioctl()
 219  */
 220 enum {
 221         /* Top level cmds */
 222         DM_VERSION_CMD = 0,
 223         DM_REMOVE_ALL_CMD,
 224         DM_LIST_DEVICES_CMD,
 225
 226         /* device level cmds */
 227         DM_DEV_CREATE_CMD,
 228         DM_DEV_REMOVE_CMD,
 229         DM_DEV_RENAME_CMD,
 230         DM_DEV_SUSPEND_CMD,
 231         DM_DEV_STATUS_CMD,
 232         DM_DEV_WAIT_CMD,
 233
 234         /* Table level cmds */
 235         DM_TABLE_LOAD_CMD,
 236         DM_TABLE_CLEAR_CMD,
 237         DM_TABLE_DEPS_CMD,
 238         DM_TABLE_STATUS_CMD,
 239
 240         /* Added later */
 241         DM_LIST_VERSIONS_CMD,
 242         DM_TARGET_MSG_CMD,
 243         DM_DEV_SET_GEOMETRY_CMD
 244 };
 245
 246 #define DM_IOCTL 0xfd
 247
 248 #define DM_VERSION       _IOWR(DM_IOCTL, DM_VERSION_CMD, struct dm_ioctl)
 249 #define DM_REMOVE_ALL    _IOWR(DM_IOCTL, DM_REMOVE_ALL_CMD, struct dm_ioctl)
 250 #define DM_LIST_DEVICES  _IOWR(DM_IOCTL, DM_LIST_DEVICES_CMD, struct dm_ioctl)
 251
 252 #define DM_DEV_CREATE    _IOWR(DM_IOCTL, DM_DEV_CREATE_CMD, struct dm_ioctl)
 253 #define DM_DEV_REMOVE    _IOWR(DM_IOCTL, DM_DEV_REMOVE_CMD, struct dm_ioctl)
 254 #define DM_DEV_RENAME    _IOWR(DM_IOCTL, DM_DEV_RENAME_CMD, struct dm_ioctl)
 255 #define DM_DEV_SUSPEND   _IOWR(DM_IOCTL, DM_DEV_SUSPEND_CMD, struct dm_ioctl)
 256 #define DM_DEV_STATUS    _IOWR(DM_IOCTL, DM_DEV_STATUS_CMD, struct dm_ioctl)
 257 #define DM_DEV_WAIT      _IOWR(DM_IOCTL, DM_DEV_WAIT_CMD, struct dm_ioctl)
 258
 259 #define DM_TABLE_LOAD    _IOWR(DM_IOCTL, DM_TABLE_LOAD_CMD, struct dm_ioctl)
 260 #define DM_TABLE_CLEAR   _IOWR(DM_IOCTL, DM_TABLE_CLEAR_CMD, struct dm_ioctl)
 261 #define DM_TABLE_DEPS    _IOWR(DM_IOCTL, DM_TABLE_DEPS_CMD, struct dm_ioctl)
 262 #define DM_TABLE_STATUS  _IOWR(DM_IOCTL, DM_TABLE_STATUS_CMD, struct dm_ioctl)
 263
 264 #define DM_LIST_VERSIONS _IOWR(DM_IOCTL, DM_LIST_VERSIONS_CMD, struct dm_ioctl)
 265
 266 #define DM_TARGET_MSG    _IOWR(DM_IOCTL, DM_TARGET_MSG_CMD, struct dm_ioctl)
 267 #define DM_DEV_SET_GEOMETRY     _IOWR(DM_IOCTL, DM_DEV_SET_GEOMETRY_CMD, struct dm_ioctl)
 268
 269 #define DM_VERSION_MAJOR        4
 270 #define DM_VERSION_MINOR        21
 271 #define DM_VERSION_PATCHLEVEL   0
 272 #define DM_VERSION_EXTRA        "-ioctl (2011-07-06)"
 273
 274 /* Status bits */
 275 #define DM_READONLY_FLAG        (1 << 0) /* In/Out */
 276 #define DM_SUSPEND_FLAG         (1 << 1) /* In/Out */
 277 #define DM_PERSISTENT_DEV_FLAG  (1 << 3) /* In */
 278
 279 /*
 280  * Flag passed into ioctl STATUS command to get table information
 281  * rather than current status.
 282  */
 283 #define DM_STATUS_TABLE_FLAG    (1 << 4) /* In */
 284
 285 /*
 286  * Flags that indicate whether a table is present in either of
 287  * the two table slots that a device has.
 288  */
 289 #define DM_ACTIVE_PRESENT_FLAG   (1 << 5) /* Out */
 290 #define DM_INACTIVE_PRESENT_FLAG (1 << 6) /* Out */
 291
 292 /*
 293  * Indicates that the buffer passed in wasn't big enough for the
 294  * results.
 295  */
 296 #define DM_BUFFER_FULL_FLAG     (1 << 8) /* Out */
 297
 298 /*
 299  * This flag is now ignored.
 300  */
 301 #define DM_SKIP_BDGET_FLAG      (1 << 9) /* In */
 302
 303 /*
 304  * Set this to avoid attempting to freeze any filesystem when suspending.
 305  */
 306 #define DM_SKIP_LOCKFS_FLAG     (1 << 10) /* In */
 307
 308 /*
 309  * Set this to suspend without flushing queued ios.
 310  */
 311 #define DM_NOFLUSH_FLAG         (1 << 11) /* In */
 312
 313 /*
 314  * If set, any table information returned will relate to the inactive
 315  * table instead of the live one.  Always check DM_INACTIVE_PRESENT_FLAG
 316  * is set before using the data returned.
 317  */
 318 #define DM_QUERY_INACTIVE_TABLE_FLAG    (1 << 12) /* In */
 319
 320 /*
 321  * If set, a uevent was generated for which the caller may need to wait.
 322  */
 323 #define DM_UEVENT_GENERATED_FLAG        (1 << 13) /* Out */
 324
 325 /*
 326  * If set, rename changes the uuid not the name.  Only permitted
 327  * if no uuid was previously supplied: an existing uuid cannot be changed.
 328  */
 329 #define DM_UUID_FLAG                    (1 << 14) /* In */
 330
 331 /*
 332  * If set, all buffers are wiped after use. Use when sending
 333  * or requesting sensitive data such as an encryption key.
 334  */
 335 #define DM_SECURE_DATA_FLAG             (1 << 15) /* In */
 336
 337 #endif                          /* _LINUX_DM_IOCTL_H */