mtd/ubi/ubi-media.h

1 /* SPDX-License-Identifier: (GPL-2.0+ OR BSD-3-Clause) */
10  * This file defines the layout of UBI headers and all the other UBI on-flash
30 /* Volume identifier header magic number (ASCII "UBI!") */
34  * Volume type constants used in the volume identifier header.
36  * @UBI_VID_DYNAMIC: dynamic volume
37  * @UBI_VID_STATIC: static volume
45  * Volume flags used in the volume table record.
47  * @UBI_VTBL_AUTORESIZE_FLG: auto-resize this volume
48  * @UBI_VTBL_SKIP_CRC_CHECK_FLG: skip the CRC check done on a static volume at
51  *				 check. Main use-case for this flag is
52  *				 boot-time reduction
54  * %UBI_VTBL_AUTORESIZE_FLG flag can be set only for one volume in the volume
55  * table. UBI automatically re-sizes the volume which has this flag and makes
56  * the volume to be of largest possible size. This means that if after the
57  * initialization UBI finds out that there are available physical eraseblocks
58  * present on the device, it automatically appends all of them to the volume
60  * reserved physical eraseblocks are not taken). So, if there is a volume with
63  * reserved for this volume. Note, the %UBI_VTBL_AUTORESIZE_FLG bit is cleared
64  * after the volume had been initialized.
66  * The auto-resize feature is useful for device production purposes. For
73  * number is required to calculate the volume sized and put them to the volume
75  * which will store the root file system) is marked as "auto-resizable", and
79  * eraseblock handling, and then re-sizes the volume, not vice-versa. This
90  * @UBI_COMPAT_DELETE: delete this internal volume before anything is written
92  * @UBI_COMPAT_RO: attach this device in read-only mode
93  * @UBI_COMPAT_PRESERVE: preserve this internal volume - do not touch its
94  *                       physical eraseblocks, don't allow the wear-leveling
95  *                       sub-system to move them
110 #define UBI_EC_HDR_SIZE_CRC  (UBI_EC_HDR_SIZE  - sizeof(__be32))
111 #define UBI_VID_HDR_SIZE_CRC (UBI_VID_HDR_SIZE - sizeof(__be32))
114  * struct ubi_ec_hdr - UBI erase counter header.
131  * is changed radically. This field is duplicated in the volume identifier
135  * volume identifier header and user data, relative to the beginning of the
151 	__be64  ec; /* Warning: the current limit is 31-bit anyway! */
160  * struct ubi_vid_hdr - on-flash UBI volume identifier header.
161  * @magic: volume identifier header magic number (%UBI_VID_HDR_MAGIC)
164  * @vol_type: volume type (%UBI_VID_DYNAMIC or %UBI_VID_STATIC)
166  *             eraseblock (for wear-leveling reasons)
167  * @compat: compatibility of this volume (%0, %UBI_COMPAT_DELETE,
169  * @vol_id: ID of this volume
173  * @used_ebs: total number of used logical eraseblocks in this volume
180  * @hdr_crc: volume identifier header CRC checksum
186  * unsigned 64-bit integer and we assume it never overflows. The @sqnum
192  * and @lnum values in the volume identifier header. Suppose we have a logical
198  * so P1 is written to, then an unclean reboot happens. Result - there are 2
204  * eraseblocks for wear-leveling reasons. If, for example, UBI moves L from P
229  * UBI purposes. In this implementation there is only one internal volume - the
230  * layout volume. Internal volumes are the main mechanism of UBI extensions.
231  * For example, in future one may introduce a journal internal volume. Internal
239  * journal volume.  And in this case, older UBI binaries, which know nothing
240  * about the journal volume, would just delete this volume and work perfectly
242  * - it just ignores the Ext3fs journal.
245  * eraseblock if this is a static volume. In case of dynamic volumes, it does
247  * data of the physical eraseblock was moved by the wear-leveling sub-system,
248  * then the wear-leveling sub-system calculates the data CRC and stores it in
255  * wear-leveling reasons. In this case, UBI calculates CRC checksum of the
260  * eraseblocks the data of the volume takes. For dynamic volumes this field is
265  * eraseblocks of this volume. This is very handy when one uses block-oriented
266  * software (say, cramfs) on top of the UBI volume.
294 #define UBI_INTERNAL_VOL_START (0x7FFFFFFF - 4096)
296 /* The layout volume contains the volume table */
302 #define UBI_LAYOUT_VOLUME_NAME   "layout volume"
308 /* The maximum volume name length */
311 /* Size of the volume table record */
314 /* Size of the volume table record without the ending CRC */
315 #define UBI_VTBL_RECORD_SIZE_CRC (UBI_VTBL_RECORD_SIZE - sizeof(__be32))
318  * struct ubi_vtbl_record - a record in the volume table.
319  * @reserved_pebs: how many physical eraseblocks are reserved for this volume
320  * @alignment: volume alignment
323  * @vol_type: volume type (%UBI_DYNAMIC_VOLUME or %UBI_STATIC_VOLUME)
324  * @upd_marker: if volume update was started but not finished
325  * @name_len: volume name length
326  * @name: the volume name
327  * @flags: volume flags (%UBI_VTBL_AUTORESIZE_FLG)
331  * The volume table records are stored in the volume table, which is stored in
332  * the layout volume. The layout volume consists of 2 logical eraseblock, each
333  * of which contains a copy of the volume table (i.e., the volume table is
334  * duplicated). The volume table is an array of &struct ubi_vtbl_record
335  * objects indexed by the volume ID.
338  * %UBI_MAX_VOLUMES records, the volume table contains %UBI_MAX_VOLUMES
342  * The @upd_marker flag is used to implement volume update. It is set to %1
344  * interrupted, UBI knows that the volume is corrupted.
346  * The @alignment field is specified when the volume is created and cannot be
347  * later changed. It may be useful, for example, when a block-oriented file
368 /* UBI fastmap on-flash data structures */
373 /* fastmap on-flash data structure format version */
397  * struct ubi_fm_sb - UBI fastmap super block
420  * struct ubi_fm_hdr - header of the fastmap data set
443  * struct ubi_fm_scan_pool - Fastmap pool PEBs to be scanned while attaching
460  * struct ubi_fm_ec - stores the erase counter of a PEB
470  * struct ubi_fm_volhdr - Fastmap volume header
472  * @magic: Fastmap volume header magic number (%UBI_FM_VHDR_MAGIC)
473  * @vol_id: volume id of the fastmapped volume
474  * @vol_type: type of the fastmapped volume
475  * @data_pad: data_pad value of the fastmapped volume
476  * @used_ebs: number of used LEBs within this volume
493  * struct ubi_fm_eba - denotes an association between a PEB and LEB