Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
2#ifndef _BTRFS_CTREE_H_
3#define _BTRFS_CTREE_H_
4
5#include <linux/btrfs.h>
6#include <linux/types.h>
7#ifdef __KERNEL__
8#include <linux/stddef.h>
9#else
10#include <stddef.h>
11#endif
12
13/* ASCII for _BHRfS_M, no terminating nul */
14#define BTRFS_MAGIC 0x4D5F53665248425FULL
15
16#define BTRFS_MAX_LEVEL 8
17
18/*
19 * We can actually store much bigger names, but lets not confuse the rest of
20 * linux.
21 */
22#define BTRFS_NAME_LEN 255
23
24/*
25 * Theoretical limit is larger, but we keep this down to a sane value. That
26 * should limit greatly the possibility of collisions on inode ref items.
27 */
28#define BTRFS_LINK_MAX 65535U
29
30/*
31 * This header contains the structure definitions and constants used
32 * by file system objects that can be retrieved using
33 * the BTRFS_IOC_SEARCH_TREE ioctl. That means basically anything that
34 * is needed to describe a leaf node's key or item contents.
35 */
36
37/* holds pointers to all of the tree roots */
38#define BTRFS_ROOT_TREE_OBJECTID 1ULL
39
40/* stores information about which extents are in use, and reference counts */
41#define BTRFS_EXTENT_TREE_OBJECTID 2ULL
42
43/*
44 * chunk tree stores translations from logical -> physical block numbering
45 * the super block points to the chunk tree
46 */
47#define BTRFS_CHUNK_TREE_OBJECTID 3ULL
48
49/*
50 * stores information about which areas of a given device are in use.
51 * one per device. The tree of tree roots points to the device tree
52 */
53#define BTRFS_DEV_TREE_OBJECTID 4ULL
54
55/* one per subvolume, storing files and directories */
56#define BTRFS_FS_TREE_OBJECTID 5ULL
57
58/* directory objectid inside the root tree */
59#define BTRFS_ROOT_TREE_DIR_OBJECTID 6ULL
60
61/* holds checksums of all the data extents */
62#define BTRFS_CSUM_TREE_OBJECTID 7ULL
63
64/* holds quota configuration and tracking */
65#define BTRFS_QUOTA_TREE_OBJECTID 8ULL
66
67/* for storing items that use the BTRFS_UUID_KEY* types */
68#define BTRFS_UUID_TREE_OBJECTID 9ULL
69
70/* tracks free space in block groups. */
71#define BTRFS_FREE_SPACE_TREE_OBJECTID 10ULL
72
73/* Holds the block group items for extent tree v2. */
74#define BTRFS_BLOCK_GROUP_TREE_OBJECTID 11ULL
75
76/* Tracks RAID stripes in block groups. */
77#define BTRFS_RAID_STRIPE_TREE_OBJECTID 12ULL
78
79/* Holds details of remapped addresses after relocation. */
80#define BTRFS_REMAP_TREE_OBJECTID 13ULL
81
82/* device stats in the device tree */
83#define BTRFS_DEV_STATS_OBJECTID 0ULL
84
85/* for storing balance parameters in the root tree */
86#define BTRFS_BALANCE_OBJECTID -4ULL
87
88/* orphan objectid for tracking unlinked/truncated files */
89#define BTRFS_ORPHAN_OBJECTID -5ULL
90
91/* does write ahead logging to speed up fsyncs */
92#define BTRFS_TREE_LOG_OBJECTID -6ULL
93#define BTRFS_TREE_LOG_FIXUP_OBJECTID -7ULL
94
95/* for space balancing */
96#define BTRFS_TREE_RELOC_OBJECTID -8ULL
97#define BTRFS_DATA_RELOC_TREE_OBJECTID -9ULL
98
99/*
100 * extent checksums all have this objectid
101 * this allows them to share the logging tree
102 * for fsyncs
103 */
104#define BTRFS_EXTENT_CSUM_OBJECTID -10ULL
105
106/* For storing free space cache */
107#define BTRFS_FREE_SPACE_OBJECTID -11ULL
108
109/*
110 * The inode number assigned to the special inode for storing
111 * free ino cache
112 */
113#define BTRFS_FREE_INO_OBJECTID -12ULL
114
115/* dummy objectid represents multiple objectids */
116#define BTRFS_MULTIPLE_OBJECTIDS -255ULL
117
118/*
119 * All files have objectids in this range.
120 */
121#define BTRFS_FIRST_FREE_OBJECTID 256ULL
122#define BTRFS_LAST_FREE_OBJECTID -256ULL
123#define BTRFS_FIRST_CHUNK_TREE_OBJECTID 256ULL
124
125
126/*
127 * the device items go into the chunk tree. The key is in the form
128 * [ 1 BTRFS_DEV_ITEM_KEY device_id ]
129 */
130#define BTRFS_DEV_ITEMS_OBJECTID 1ULL
131
132#define BTRFS_BTREE_INODE_OBJECTID 1
133
134#define BTRFS_EMPTY_SUBVOL_DIR_OBJECTID 2
135
136#define BTRFS_DEV_REPLACE_DEVID 0ULL
137
138/*
139 * inode items have the data typically returned from stat and store other
140 * info about object characteristics. There is one for every file and dir in
141 * the FS
142 */
143#define BTRFS_INODE_ITEM_KEY 1
144#define BTRFS_INODE_REF_KEY 12
145#define BTRFS_INODE_EXTREF_KEY 13
146#define BTRFS_XATTR_ITEM_KEY 24
147
148/*
149 * fs verity items are stored under two different key types on disk.
150 * The descriptor items:
151 * [ inode objectid, BTRFS_VERITY_DESC_ITEM_KEY, offset ]
152 *
153 * At offset 0, we store a btrfs_verity_descriptor_item which tracks the size
154 * of the descriptor item and some extra data for encryption.
155 * Starting at offset 1, these hold the generic fs verity descriptor. The
156 * latter are opaque to btrfs, we just read and write them as a blob for the
157 * higher level verity code. The most common descriptor size is 256 bytes.
158 *
159 * The merkle tree items:
160 * [ inode objectid, BTRFS_VERITY_MERKLE_ITEM_KEY, offset ]
161 *
162 * These also start at offset 0, and correspond to the merkle tree bytes. When
163 * fsverity asks for page 0 of the merkle tree, we pull up one page starting at
164 * offset 0 for this key type. These are also opaque to btrfs, we're blindly
165 * storing whatever fsverity sends down.
166 */
167#define BTRFS_VERITY_DESC_ITEM_KEY 36
168#define BTRFS_VERITY_MERKLE_ITEM_KEY 37
169
170#define BTRFS_ORPHAN_ITEM_KEY 48
171/* reserve 2-15 close to the inode for later flexibility */
172
173/*
174 * dir items are the name -> inode pointers in a directory. There is one
175 * for every name in a directory. BTRFS_DIR_LOG_ITEM_KEY is no longer used
176 * but it's still defined here for documentation purposes and to help avoid
177 * having its numerical value reused in the future.
178 */
179#define BTRFS_DIR_LOG_ITEM_KEY 60
180#define BTRFS_DIR_LOG_INDEX_KEY 72
181#define BTRFS_DIR_ITEM_KEY 84
182#define BTRFS_DIR_INDEX_KEY 96
183/*
184 * extent data is for file data
185 */
186#define BTRFS_EXTENT_DATA_KEY 108
187
188/*
189 * extent csums are stored in a separate tree and hold csums for
190 * an entire extent on disk.
191 */
192#define BTRFS_EXTENT_CSUM_KEY 128
193
194/*
195 * root items point to tree roots. They are typically in the root
196 * tree used by the super block to find all the other trees
197 */
198#define BTRFS_ROOT_ITEM_KEY 132
199
200/*
201 * root backrefs tie subvols and snapshots to the directory entries that
202 * reference them
203 */
204#define BTRFS_ROOT_BACKREF_KEY 144
205
206/*
207 * root refs make a fast index for listing all of the snapshots and
208 * subvolumes referenced by a given root. They point directly to the
209 * directory item in the root that references the subvol
210 */
211#define BTRFS_ROOT_REF_KEY 156
212
213/*
214 * extent items are in the extent map tree. These record which blocks
215 * are used, and how many references there are to each block
216 */
217#define BTRFS_EXTENT_ITEM_KEY 168
218
219/*
220 * The same as the BTRFS_EXTENT_ITEM_KEY, except it's metadata we already know
221 * the length, so we save the level in key->offset instead of the length.
222 */
223#define BTRFS_METADATA_ITEM_KEY 169
224
225/*
226 * Special inline ref key which stores the id of the subvolume which originally
227 * created the extent. This subvolume owns the extent permanently from the
228 * perspective of simple quotas. Needed to know which subvolume to free quota
229 * usage from when the extent is deleted.
230 *
231 * Stored as an inline ref rather to avoid wasting space on a separate item on
232 * top of the existing extent item. However, unlike the other inline refs,
233 * there is one one owner ref per extent rather than one per extent.
234 *
235 * Because of this, it goes at the front of the list of inline refs, and thus
236 * must have a lower type value than any other inline ref type (to satisfy the
237 * disk format rule that inline refs have non-decreasing type).
238 */
239#define BTRFS_EXTENT_OWNER_REF_KEY 172
240
241#define BTRFS_TREE_BLOCK_REF_KEY 176
242
243#define BTRFS_EXTENT_DATA_REF_KEY 178
244
245/*
246 * Obsolete key. Defintion removed in 6.6, value may be reused in the future.
247 *
248 * #define BTRFS_EXTENT_REF_V0_KEY 180
249 */
250
251#define BTRFS_SHARED_BLOCK_REF_KEY 182
252
253#define BTRFS_SHARED_DATA_REF_KEY 184
254
255/*
256 * block groups give us hints into the extent allocation trees. Which
257 * blocks are free etc etc
258 */
259#define BTRFS_BLOCK_GROUP_ITEM_KEY 192
260
261/*
262 * Every block group is represented in the free space tree by a free space info
263 * item, which stores some accounting information. It is keyed on
264 * (block_group_start, FREE_SPACE_INFO, block_group_length).
265 */
266#define BTRFS_FREE_SPACE_INFO_KEY 198
267
268/*
269 * A free space extent tracks an extent of space that is free in a block group.
270 * It is keyed on (start, FREE_SPACE_EXTENT, length).
271 */
272#define BTRFS_FREE_SPACE_EXTENT_KEY 199
273
274/*
275 * When a block group becomes very fragmented, we convert it to use bitmaps
276 * instead of extents. A free space bitmap is keyed on
277 * (start, FREE_SPACE_BITMAP, length); the corresponding item is a bitmap with
278 * (length / sectorsize) bits.
279 */
280#define BTRFS_FREE_SPACE_BITMAP_KEY 200
281
282#define BTRFS_DEV_EXTENT_KEY 204
283#define BTRFS_DEV_ITEM_KEY 216
284#define BTRFS_CHUNK_ITEM_KEY 228
285
286#define BTRFS_RAID_STRIPE_KEY 230
287
288#define BTRFS_IDENTITY_REMAP_KEY 234
289#define BTRFS_REMAP_KEY 235
290#define BTRFS_REMAP_BACKREF_KEY 236
291
292/*
293 * Records the overall state of the qgroups.
294 * There's only one instance of this key present,
295 * (0, BTRFS_QGROUP_STATUS_KEY, 0)
296 */
297#define BTRFS_QGROUP_STATUS_KEY 240
298/*
299 * Records the currently used space of the qgroup.
300 * One key per qgroup, (0, BTRFS_QGROUP_INFO_KEY, qgroupid).
301 */
302#define BTRFS_QGROUP_INFO_KEY 242
303/*
304 * Contains the user configured limits for the qgroup.
305 * One key per qgroup, (0, BTRFS_QGROUP_LIMIT_KEY, qgroupid).
306 */
307#define BTRFS_QGROUP_LIMIT_KEY 244
308/*
309 * Records the child-parent relationship of qgroups. For
310 * each relation, 2 keys are present:
311 * (childid, BTRFS_QGROUP_RELATION_KEY, parentid)
312 * (parentid, BTRFS_QGROUP_RELATION_KEY, childid)
313 */
314#define BTRFS_QGROUP_RELATION_KEY 246
315
316/*
317 * Obsolete name, see BTRFS_TEMPORARY_ITEM_KEY.
318 */
319#define BTRFS_BALANCE_ITEM_KEY 248
320
321/*
322 * The key type for tree items that are stored persistently, but do not need to
323 * exist for extended period of time. The items can exist in any tree.
324 *
325 * [subtype, BTRFS_TEMPORARY_ITEM_KEY, data]
326 *
327 * Existing items:
328 *
329 * - balance status item
330 * (BTRFS_BALANCE_OBJECTID, BTRFS_TEMPORARY_ITEM_KEY, 0)
331 */
332#define BTRFS_TEMPORARY_ITEM_KEY 248
333
334/*
335 * Obsolete name, see BTRFS_PERSISTENT_ITEM_KEY
336 */
337#define BTRFS_DEV_STATS_KEY 249
338
339/*
340 * The key type for tree items that are stored persistently and usually exist
341 * for a long period, eg. filesystem lifetime. The item kinds can be status
342 * information, stats or preference values. The item can exist in any tree.
343 *
344 * [subtype, BTRFS_PERSISTENT_ITEM_KEY, data]
345 *
346 * Existing items:
347 *
348 * - device statistics, store IO stats in the device tree, one key for all
349 * stats
350 * (BTRFS_DEV_STATS_OBJECTID, BTRFS_DEV_STATS_KEY, 0)
351 */
352#define BTRFS_PERSISTENT_ITEM_KEY 249
353
354/*
355 * Persistently stores the device replace state in the device tree.
356 * The key is built like this: (0, BTRFS_DEV_REPLACE_KEY, 0).
357 */
358#define BTRFS_DEV_REPLACE_KEY 250
359
360/*
361 * Stores items that allow to quickly map UUIDs to something else.
362 * These items are part of the filesystem UUID tree.
363 * The key is built like this:
364 * (UUID_upper_64_bits, BTRFS_UUID_KEY*, UUID_lower_64_bits).
365 */
366#if BTRFS_UUID_SIZE != 16
367#error "UUID items require BTRFS_UUID_SIZE == 16!"
368#endif
369#define BTRFS_UUID_KEY_SUBVOL 251 /* for UUIDs assigned to subvols */
370#define BTRFS_UUID_KEY_RECEIVED_SUBVOL 252 /* for UUIDs assigned to
371 * received subvols */
372
373/*
374 * string items are for debugging. They just store a short string of
375 * data in the FS
376 */
377#define BTRFS_STRING_ITEM_KEY 253
378
379/* Maximum metadata block size (nodesize) */
380#define BTRFS_MAX_METADATA_BLOCKSIZE 65536
381
382/* 32 bytes in various csum fields */
383#define BTRFS_CSUM_SIZE 32
384
385/* csum types */
386enum btrfs_csum_type {
387 BTRFS_CSUM_TYPE_CRC32 = 0,
388 BTRFS_CSUM_TYPE_XXHASH = 1,
389 BTRFS_CSUM_TYPE_SHA256 = 2,
390 BTRFS_CSUM_TYPE_BLAKE2 = 3,
391};
392
393/*
394 * flags definitions for directory entry item type
395 *
396 * Used by:
397 * struct btrfs_dir_item.type
398 *
399 * Values 0..7 must match common file type values in fs_types.h.
400 */
401#define BTRFS_FT_UNKNOWN 0
402#define BTRFS_FT_REG_FILE 1
403#define BTRFS_FT_DIR 2
404#define BTRFS_FT_CHRDEV 3
405#define BTRFS_FT_BLKDEV 4
406#define BTRFS_FT_FIFO 5
407#define BTRFS_FT_SOCK 6
408#define BTRFS_FT_SYMLINK 7
409#define BTRFS_FT_XATTR 8
410#define BTRFS_FT_MAX 9
411/* Directory contains encrypted data */
412#define BTRFS_FT_ENCRYPTED 0x80
413
414static inline __u8 btrfs_dir_flags_to_ftype(__u8 flags)
415{
416 return flags & ~BTRFS_FT_ENCRYPTED;
417}
418
419/*
420 * Inode flags
421 */
422#define BTRFS_INODE_NODATASUM (1U << 0)
423#define BTRFS_INODE_NODATACOW (1U << 1)
424#define BTRFS_INODE_READONLY (1U << 2)
425#define BTRFS_INODE_NOCOMPRESS (1U << 3)
426#define BTRFS_INODE_PREALLOC (1U << 4)
427#define BTRFS_INODE_SYNC (1U << 5)
428#define BTRFS_INODE_IMMUTABLE (1U << 6)
429#define BTRFS_INODE_APPEND (1U << 7)
430#define BTRFS_INODE_NODUMP (1U << 8)
431#define BTRFS_INODE_NOATIME (1U << 9)
432#define BTRFS_INODE_DIRSYNC (1U << 10)
433#define BTRFS_INODE_COMPRESS (1U << 11)
434
435#define BTRFS_INODE_ROOT_ITEM_INIT (1U << 31)
436
437#define BTRFS_INODE_FLAG_MASK \
438 (BTRFS_INODE_NODATASUM | \
439 BTRFS_INODE_NODATACOW | \
440 BTRFS_INODE_READONLY | \
441 BTRFS_INODE_NOCOMPRESS | \
442 BTRFS_INODE_PREALLOC | \
443 BTRFS_INODE_SYNC | \
444 BTRFS_INODE_IMMUTABLE | \
445 BTRFS_INODE_APPEND | \
446 BTRFS_INODE_NODUMP | \
447 BTRFS_INODE_NOATIME | \
448 BTRFS_INODE_DIRSYNC | \
449 BTRFS_INODE_COMPRESS | \
450 BTRFS_INODE_ROOT_ITEM_INIT)
451
452#define BTRFS_INODE_RO_VERITY (1U << 0)
453
454#define BTRFS_INODE_RO_FLAG_MASK (BTRFS_INODE_RO_VERITY)
455
456/*
457 * The key defines the order in the tree, and so it also defines (optimal)
458 * block layout.
459 *
460 * objectid corresponds to the inode number.
461 *
462 * type tells us things about the object, and is a kind of stream selector.
463 * so for a given inode, keys with type of 1 might refer to the inode data,
464 * type of 2 may point to file data in the btree and type == 3 may point to
465 * extents.
466 *
467 * offset is the starting byte offset for this key in the stream.
468 *
469 * btrfs_disk_key is in disk byte order. struct btrfs_key is always
470 * in cpu native order. Otherwise they are identical and their sizes
471 * should be the same (ie both packed)
472 */
473struct btrfs_disk_key {
474 __le64 objectid;
475 __u8 type;
476 __le64 offset;
477} __attribute__ ((__packed__));
478
479struct btrfs_key {
480 __u64 objectid;
481 __u8 type;
482 __u64 offset;
483} __attribute__ ((__packed__));
484
485/*
486 * Every tree block (leaf or node) starts with this header.
487 */
488struct btrfs_header {
489 /* These first four must match the super block */
490 __u8 csum[BTRFS_CSUM_SIZE];
491 /* FS specific uuid */
492 __u8 fsid[BTRFS_FSID_SIZE];
493 /* Which block this node is supposed to live in */
494 __le64 bytenr;
495 __le64 flags;
496
497 /* Allowed to be different from the super from here on down */
498 __u8 chunk_tree_uuid[BTRFS_UUID_SIZE];
499 __le64 generation;
500 __le64 owner;
501 __le32 nritems;
502 __u8 level;
503} __attribute__ ((__packed__));
504
505/*
506 * This is a very generous portion of the super block, giving us room to
507 * translate 14 chunks with 3 stripes each.
508 */
509#define BTRFS_SYSTEM_CHUNK_ARRAY_SIZE 2048
510
511/*
512 * Just in case we somehow lose the roots and are not able to mount, we store
513 * an array of the roots from previous transactions in the super.
514 */
515#define BTRFS_NUM_BACKUP_ROOTS 4
516struct btrfs_root_backup {
517 __le64 tree_root;
518 __le64 tree_root_gen;
519
520 __le64 chunk_root;
521 __le64 chunk_root_gen;
522
523 __le64 extent_root;
524 __le64 extent_root_gen;
525
526 __le64 fs_root;
527 __le64 fs_root_gen;
528
529 __le64 dev_root;
530 __le64 dev_root_gen;
531
532 __le64 csum_root;
533 __le64 csum_root_gen;
534
535 __le64 total_bytes;
536 __le64 bytes_used;
537 __le64 num_devices;
538 /* future */
539 __le64 unused_64[4];
540
541 __u8 tree_root_level;
542 __u8 chunk_root_level;
543 __u8 extent_root_level;
544 __u8 fs_root_level;
545 __u8 dev_root_level;
546 __u8 csum_root_level;
547 /* future and to align */
548 __u8 unused_8[10];
549} __attribute__ ((__packed__));
550
551/*
552 * A leaf is full of items. offset and size tell us where to find the item in
553 * the leaf (relative to the start of the data area)
554 */
555struct btrfs_item {
556 struct btrfs_disk_key key;
557 __le32 offset;
558 __le32 size;
559} __attribute__ ((__packed__));
560
561/*
562 * Leaves have an item area and a data area:
563 * [item0, item1....itemN] [free space] [dataN...data1, data0]
564 *
565 * The data is separate from the items to get the keys closer together during
566 * searches.
567 */
568struct btrfs_leaf {
569 struct btrfs_header header;
570 struct btrfs_item items[];
571} __attribute__ ((__packed__));
572
573/*
574 * All non-leaf blocks are nodes, they hold only keys and pointers to other
575 * blocks.
576 */
577struct btrfs_key_ptr {
578 struct btrfs_disk_key key;
579 __le64 blockptr;
580 __le64 generation;
581} __attribute__ ((__packed__));
582
583struct btrfs_node {
584 struct btrfs_header header;
585 struct btrfs_key_ptr ptrs[];
586} __attribute__ ((__packed__));
587
588struct btrfs_dev_item {
589 /* the internal btrfs device id */
590 __le64 devid;
591
592 /* size of the device */
593 __le64 total_bytes;
594
595 /* bytes used */
596 __le64 bytes_used;
597
598 /* optimal io alignment for this device */
599 __le32 io_align;
600
601 /* optimal io width for this device */
602 __le32 io_width;
603
604 /* minimal io size for this device */
605 __le32 sector_size;
606
607 /* type and info about this device */
608 __le64 type;
609
610 /* expected generation for this device */
611 __le64 generation;
612
613 /*
614 * starting byte of this partition on the device,
615 * to allow for stripe alignment in the future
616 */
617 __le64 start_offset;
618
619 /* grouping information for allocation decisions */
620 __le32 dev_group;
621
622 /* seek speed 0-100 where 100 is fastest */
623 __u8 seek_speed;
624
625 /* bandwidth 0-100 where 100 is fastest */
626 __u8 bandwidth;
627
628 /* btrfs generated uuid for this device */
629 __u8 uuid[BTRFS_UUID_SIZE];
630
631 /* uuid of FS who owns this device */
632 __u8 fsid[BTRFS_UUID_SIZE];
633} __attribute__ ((__packed__));
634
635struct btrfs_stripe {
636 __le64 devid;
637 __le64 offset;
638 __u8 dev_uuid[BTRFS_UUID_SIZE];
639} __attribute__ ((__packed__));
640
641struct btrfs_chunk {
642 /* size of this chunk in bytes */
643 __le64 length;
644
645 /* objectid of the root referencing this chunk */
646 __le64 owner;
647
648 __le64 stripe_len;
649 __le64 type;
650
651 /* optimal io alignment for this chunk */
652 __le32 io_align;
653
654 /* optimal io width for this chunk */
655 __le32 io_width;
656
657 /* minimal io size for this chunk */
658 __le32 sector_size;
659
660 /* 2^16 stripes is quite a lot, a second limit is the size of a single
661 * item in the btree
662 */
663 __le16 num_stripes;
664
665 /* sub stripes only matter for raid10 */
666 __le16 sub_stripes;
667 struct btrfs_stripe stripe;
668 /* additional stripes go here */
669} __attribute__ ((__packed__));
670
671/*
672 * The super block basically lists the main trees of the FS.
673 */
674struct btrfs_super_block {
675 /* The first 4 fields must match struct btrfs_header */
676 __u8 csum[BTRFS_CSUM_SIZE];
677 /* FS specific UUID, visible to user */
678 __u8 fsid[BTRFS_FSID_SIZE];
679 /* This block number */
680 __le64 bytenr;
681 __le64 flags;
682
683 /* Allowed to be different from the btrfs_header from here own down */
684 __le64 magic;
685 __le64 generation;
686 __le64 root;
687 __le64 chunk_root;
688 __le64 log_root;
689
690 /*
691 * This member has never been utilized since the very beginning, thus
692 * it's always 0 regardless of kernel version. We always use
693 * generation + 1 to read log tree root. So here we mark it deprecated.
694 */
695 __le64 __unused_log_root_transid;
696 __le64 total_bytes;
697 __le64 bytes_used;
698 __le64 root_dir_objectid;
699 __le64 num_devices;
700 __le32 sectorsize;
701 __le32 nodesize;
702 __le32 __unused_leafsize;
703 __le32 stripesize;
704 __le32 sys_chunk_array_size;
705 __le64 chunk_root_generation;
706 __le64 compat_flags;
707 __le64 compat_ro_flags;
708 __le64 incompat_flags;
709 __le16 csum_type;
710 __u8 root_level;
711 __u8 chunk_root_level;
712 __u8 log_root_level;
713 struct btrfs_dev_item dev_item;
714
715 char label[BTRFS_LABEL_SIZE];
716
717 __le64 cache_generation;
718 __le64 uuid_tree_generation;
719
720 /* The UUID written into btree blocks */
721 __u8 metadata_uuid[BTRFS_FSID_SIZE];
722
723 __u64 nr_global_roots;
724 __le64 remap_root;
725 __le64 remap_root_generation;
726 __u8 remap_root_level;
727
728 /* Future expansion */
729 __u8 reserved[199];
730 __u8 sys_chunk_array[BTRFS_SYSTEM_CHUNK_ARRAY_SIZE];
731 struct btrfs_root_backup super_roots[BTRFS_NUM_BACKUP_ROOTS];
732
733 /* Padded to 4096 bytes */
734 __u8 padding[565];
735} __attribute__ ((__packed__));
736
737#define BTRFS_FREE_SPACE_EXTENT 1
738#define BTRFS_FREE_SPACE_BITMAP 2
739
740struct btrfs_free_space_entry {
741 __le64 offset;
742 __le64 bytes;
743 __u8 type;
744} __attribute__ ((__packed__));
745
746struct btrfs_free_space_header {
747 struct btrfs_disk_key location;
748 __le64 generation;
749 __le64 num_entries;
750 __le64 num_bitmaps;
751} __attribute__ ((__packed__));
752
753struct btrfs_raid_stride {
754 /* The id of device this raid extent lives on. */
755 __le64 devid;
756 /* The physical location on disk. */
757 __le64 physical;
758} __attribute__ ((__packed__));
759
760struct btrfs_stripe_extent {
761 /* An array of raid strides this stripe is composed of. */
762 __DECLARE_FLEX_ARRAY(struct btrfs_raid_stride, strides);
763} __attribute__ ((__packed__));
764
765#define BTRFS_HEADER_FLAG_WRITTEN (1ULL << 0)
766#define BTRFS_HEADER_FLAG_RELOC (1ULL << 1)
767
768/* Super block flags */
769/* Errors detected */
770#define BTRFS_SUPER_FLAG_ERROR (1ULL << 2)
771
772#define BTRFS_SUPER_FLAG_SEEDING (1ULL << 32)
773#define BTRFS_SUPER_FLAG_METADUMP (1ULL << 33)
774#define BTRFS_SUPER_FLAG_METADUMP_V2 (1ULL << 34)
775#define BTRFS_SUPER_FLAG_CHANGING_FSID (1ULL << 35)
776#define BTRFS_SUPER_FLAG_CHANGING_FSID_V2 (1ULL << 36)
777
778/*
779 * Those are temporaray flags utilized by btrfs-progs to do offline conversion.
780 * They are rejected by kernel.
781 * But still keep them all here to avoid conflicts.
782 */
783#define BTRFS_SUPER_FLAG_CHANGING_BG_TREE (1ULL << 38)
784#define BTRFS_SUPER_FLAG_CHANGING_DATA_CSUM (1ULL << 39)
785#define BTRFS_SUPER_FLAG_CHANGING_META_CSUM (1ULL << 40)
786
787/*
788 * items in the extent btree are used to record the objectid of the
789 * owner of the block and the number of references
790 */
791
792struct btrfs_extent_item {
793 __le64 refs;
794 __le64 generation;
795 __le64 flags;
796} __attribute__ ((__packed__));
797
798struct btrfs_extent_item_v0 {
799 __le32 refs;
800} __attribute__ ((__packed__));
801
802
803#define BTRFS_EXTENT_FLAG_DATA (1ULL << 0)
804#define BTRFS_EXTENT_FLAG_TREE_BLOCK (1ULL << 1)
805
806/* following flags only apply to tree blocks */
807
808/* use full backrefs for extent pointers in the block */
809#define BTRFS_BLOCK_FLAG_FULL_BACKREF (1ULL << 8)
810
811#define BTRFS_BACKREF_REV_MAX 256
812#define BTRFS_BACKREF_REV_SHIFT 56
813#define BTRFS_BACKREF_REV_MASK (((u64)BTRFS_BACKREF_REV_MAX - 1) << \
814 BTRFS_BACKREF_REV_SHIFT)
815
816#define BTRFS_OLD_BACKREF_REV 0
817#define BTRFS_MIXED_BACKREF_REV 1
818
819/*
820 * this flag is only used internally by scrub and may be changed at any time
821 * it is only declared here to avoid collisions
822 */
823#define BTRFS_EXTENT_FLAG_SUPER (1ULL << 48)
824
825struct btrfs_tree_block_info {
826 struct btrfs_disk_key key;
827 __u8 level;
828} __attribute__ ((__packed__));
829
830struct btrfs_extent_data_ref {
831 __le64 root;
832 __le64 objectid;
833 __le64 offset;
834 __le32 count;
835} __attribute__ ((__packed__));
836
837struct btrfs_shared_data_ref {
838 __le32 count;
839} __attribute__ ((__packed__));
840
841struct btrfs_extent_owner_ref {
842 __le64 root_id;
843} __attribute__ ((__packed__));
844
845struct btrfs_extent_inline_ref {
846 __u8 type;
847 __le64 offset;
848} __attribute__ ((__packed__));
849
850/* dev extents record free space on individual devices. The owner
851 * field points back to the chunk allocation mapping tree that allocated
852 * the extent. The chunk tree uuid field is a way to double check the owner
853 */
854struct btrfs_dev_extent {
855 __le64 chunk_tree;
856 __le64 chunk_objectid;
857 __le64 chunk_offset;
858 __le64 length;
859 __u8 chunk_tree_uuid[BTRFS_UUID_SIZE];
860} __attribute__ ((__packed__));
861
862struct btrfs_inode_ref {
863 __le64 index;
864 __le16 name_len;
865 /* name goes here */
866} __attribute__ ((__packed__));
867
868struct btrfs_inode_extref {
869 __le64 parent_objectid;
870 __le64 index;
871 __le16 name_len;
872 __u8 name[];
873 /* name goes here */
874} __attribute__ ((__packed__));
875
876struct btrfs_timespec {
877 __le64 sec;
878 __le32 nsec;
879} __attribute__ ((__packed__));
880
881struct btrfs_inode_item {
882 /* nfs style generation number */
883 __le64 generation;
884 /* transid that last touched this inode */
885 __le64 transid;
886 __le64 size;
887 __le64 nbytes;
888 __le64 block_group;
889 __le32 nlink;
890 __le32 uid;
891 __le32 gid;
892 __le32 mode;
893 __le64 rdev;
894 __le64 flags;
895
896 /* modification sequence number for NFS */
897 __le64 sequence;
898
899 /*
900 * a little future expansion, for more than this we can
901 * just grow the inode item and version it
902 */
903 __le64 reserved[4];
904 struct btrfs_timespec atime;
905 struct btrfs_timespec ctime;
906 struct btrfs_timespec mtime;
907 struct btrfs_timespec otime;
908} __attribute__ ((__packed__));
909
910struct btrfs_dir_log_item {
911 __le64 end;
912} __attribute__ ((__packed__));
913
914struct btrfs_dir_item {
915 struct btrfs_disk_key location;
916 __le64 transid;
917 __le16 data_len;
918 __le16 name_len;
919 __u8 type;
920} __attribute__ ((__packed__));
921
922#define BTRFS_ROOT_SUBVOL_RDONLY (1ULL << 0)
923
924/*
925 * Internal in-memory flag that a subvolume has been marked for deletion but
926 * still visible as a directory
927 */
928#define BTRFS_ROOT_SUBVOL_DEAD (1ULL << 48)
929
930struct btrfs_root_item {
931 struct btrfs_inode_item inode;
932 __le64 generation;
933 __le64 root_dirid;
934 __le64 bytenr;
935 __le64 byte_limit;
936 __le64 bytes_used;
937 __le64 last_snapshot;
938 __le64 flags;
939 __le32 refs;
940 struct btrfs_disk_key drop_progress;
941 __u8 drop_level;
942 __u8 level;
943
944 /*
945 * The following fields appear after subvol_uuids+subvol_times
946 * were introduced.
947 */
948
949 /*
950 * This generation number is used to test if the new fields are valid
951 * and up to date while reading the root item. Every time the root item
952 * is written out, the "generation" field is copied into this field. If
953 * anyone ever mounted the fs with an older kernel, we will have
954 * mismatching generation values here and thus must invalidate the
955 * new fields. See btrfs_update_root and btrfs_find_last_root for
956 * details.
957 * the offset of generation_v2 is also used as the start for the memset
958 * when invalidating the fields.
959 */
960 __le64 generation_v2;
961 __u8 uuid[BTRFS_UUID_SIZE];
962 __u8 parent_uuid[BTRFS_UUID_SIZE];
963 __u8 received_uuid[BTRFS_UUID_SIZE];
964 __le64 ctransid; /* updated when an inode changes */
965 __le64 otransid; /* trans when created */
966 __le64 stransid; /* trans when sent. non-zero for received subvol */
967 __le64 rtransid; /* trans when received. non-zero for received subvol */
968 struct btrfs_timespec ctime;
969 struct btrfs_timespec otime;
970 struct btrfs_timespec stime;
971 struct btrfs_timespec rtime;
972 __le64 reserved[8]; /* for future */
973} __attribute__ ((__packed__));
974
975/*
976 * Btrfs root item used to be smaller than current size. The old format ends
977 * at where member generation_v2 is.
978 */
979static inline __u32 btrfs_legacy_root_item_size(void)
980{
981 return offsetof(struct btrfs_root_item, generation_v2);
982}
983
984/*
985 * this is used for both forward and backward root refs
986 */
987struct btrfs_root_ref {
988 __le64 dirid;
989 __le64 sequence;
990 __le16 name_len;
991} __attribute__ ((__packed__));
992
993struct btrfs_disk_balance_args {
994 /*
995 * profiles to operate on, single is denoted by
996 * BTRFS_AVAIL_ALLOC_BIT_SINGLE
997 */
998 __le64 profiles;
999
1000 /*
1001 * usage filter
1002 * BTRFS_BALANCE_ARGS_USAGE with a single value means '0..N'
1003 * BTRFS_BALANCE_ARGS_USAGE_RANGE - range syntax, min..max
1004 */
1005 union {
1006 __le64 usage;
1007 struct {
1008 __le32 usage_min;
1009 __le32 usage_max;
1010 };
1011 };
1012
1013 /* devid filter */
1014 __le64 devid;
1015
1016 /* devid subset filter [pstart..pend) */
1017 __le64 pstart;
1018 __le64 pend;
1019
1020 /* btrfs virtual address space subset filter [vstart..vend) */
1021 __le64 vstart;
1022 __le64 vend;
1023
1024 /*
1025 * profile to convert to, single is denoted by
1026 * BTRFS_AVAIL_ALLOC_BIT_SINGLE
1027 */
1028 __le64 target;
1029
1030 /* BTRFS_BALANCE_ARGS_* */
1031 __le64 flags;
1032
1033 /*
1034 * BTRFS_BALANCE_ARGS_LIMIT with value 'limit'
1035 * BTRFS_BALANCE_ARGS_LIMIT_RANGE - the extend version can use minimum
1036 * and maximum
1037 */
1038 union {
1039 __le64 limit;
1040 struct {
1041 __le32 limit_min;
1042 __le32 limit_max;
1043 };
1044 };
1045
1046 /*
1047 * Process chunks that cross stripes_min..stripes_max devices,
1048 * BTRFS_BALANCE_ARGS_STRIPES_RANGE
1049 */
1050 __le32 stripes_min;
1051 __le32 stripes_max;
1052
1053 __le64 unused[6];
1054} __attribute__ ((__packed__));
1055
1056/*
1057 * store balance parameters to disk so that balance can be properly
1058 * resumed after crash or unmount
1059 */
1060struct btrfs_balance_item {
1061 /* BTRFS_BALANCE_* */
1062 __le64 flags;
1063
1064 struct btrfs_disk_balance_args data;
1065 struct btrfs_disk_balance_args meta;
1066 struct btrfs_disk_balance_args sys;
1067
1068 __le64 unused[4];
1069} __attribute__ ((__packed__));
1070
1071enum {
1072 BTRFS_FILE_EXTENT_INLINE = 0,
1073 BTRFS_FILE_EXTENT_REG = 1,
1074 BTRFS_FILE_EXTENT_PREALLOC = 2,
1075 BTRFS_NR_FILE_EXTENT_TYPES = 3,
1076};
1077
1078struct btrfs_file_extent_item {
1079 /*
1080 * transaction id that created this extent
1081 */
1082 __le64 generation;
1083 /*
1084 * max number of bytes to hold this extent in ram
1085 * when we split a compressed extent we can't know how big
1086 * each of the resulting pieces will be. So, this is
1087 * an upper limit on the size of the extent in ram instead of
1088 * an exact limit.
1089 */
1090 __le64 ram_bytes;
1091
1092 /*
1093 * 32 bits for the various ways we might encode the data,
1094 * including compression and encryption. If any of these
1095 * are set to something a given disk format doesn't understand
1096 * it is treated like an incompat flag for reading and writing,
1097 * but not for stat.
1098 */
1099 __u8 compression;
1100 __u8 encryption;
1101 __le16 other_encoding; /* spare for later use */
1102
1103 /* are we inline data or a real extent? */
1104 __u8 type;
1105
1106 /*
1107 * disk space consumed by the extent, checksum blocks are included
1108 * in these numbers
1109 *
1110 * At this offset in the structure, the inline extent data start.
1111 */
1112 __le64 disk_bytenr;
1113 __le64 disk_num_bytes;
1114 /*
1115 * the logical offset in file blocks (no csums)
1116 * this extent record is for. This allows a file extent to point
1117 * into the middle of an existing extent on disk, sharing it
1118 * between two snapshots (useful if some bytes in the middle of the
1119 * extent have changed
1120 */
1121 __le64 offset;
1122 /*
1123 * the logical number of file blocks (no csums included). This
1124 * always reflects the size uncompressed and without encoding.
1125 */
1126 __le64 num_bytes;
1127
1128} __attribute__ ((__packed__));
1129
1130struct btrfs_csum_item {
1131 __u8 csum;
1132} __attribute__ ((__packed__));
1133
1134struct btrfs_dev_stats_item {
1135 /*
1136 * grow this item struct at the end for future enhancements and keep
1137 * the existing values unchanged
1138 */
1139 __le64 values[BTRFS_DEV_STAT_VALUES_MAX];
1140} __attribute__ ((__packed__));
1141
1142#define BTRFS_DEV_REPLACE_ITEM_CONT_READING_FROM_SRCDEV_MODE_ALWAYS 0
1143#define BTRFS_DEV_REPLACE_ITEM_CONT_READING_FROM_SRCDEV_MODE_AVOID 1
1144
1145struct btrfs_dev_replace_item {
1146 /*
1147 * grow this item struct at the end for future enhancements and keep
1148 * the existing values unchanged
1149 */
1150 __le64 src_devid;
1151 __le64 cursor_left;
1152 __le64 cursor_right;
1153 __le64 cont_reading_from_srcdev_mode;
1154
1155 __le64 replace_state;
1156 __le64 time_started;
1157 __le64 time_stopped;
1158 __le64 num_write_errors;
1159 __le64 num_uncorrectable_read_errors;
1160} __attribute__ ((__packed__));
1161
1162/* different types of block groups (and chunks) */
1163#define BTRFS_BLOCK_GROUP_DATA (1ULL << 0)
1164#define BTRFS_BLOCK_GROUP_SYSTEM (1ULL << 1)
1165#define BTRFS_BLOCK_GROUP_METADATA (1ULL << 2)
1166#define BTRFS_BLOCK_GROUP_RAID0 (1ULL << 3)
1167#define BTRFS_BLOCK_GROUP_RAID1 (1ULL << 4)
1168#define BTRFS_BLOCK_GROUP_DUP (1ULL << 5)
1169#define BTRFS_BLOCK_GROUP_RAID10 (1ULL << 6)
1170#define BTRFS_BLOCK_GROUP_RAID5 (1ULL << 7)
1171#define BTRFS_BLOCK_GROUP_RAID6 (1ULL << 8)
1172#define BTRFS_BLOCK_GROUP_RAID1C3 (1ULL << 9)
1173#define BTRFS_BLOCK_GROUP_RAID1C4 (1ULL << 10)
1174#define BTRFS_BLOCK_GROUP_REMAPPED (1ULL << 11)
1175#define BTRFS_BLOCK_GROUP_METADATA_REMAP (1ULL << 12)
1176#define BTRFS_BLOCK_GROUP_RESERVED (BTRFS_AVAIL_ALLOC_BIT_SINGLE | \
1177 BTRFS_SPACE_INFO_GLOBAL_RSV)
1178
1179#define BTRFS_BLOCK_GROUP_TYPE_MASK (BTRFS_BLOCK_GROUP_DATA | \
1180 BTRFS_BLOCK_GROUP_SYSTEM | \
1181 BTRFS_BLOCK_GROUP_METADATA | \
1182 BTRFS_BLOCK_GROUP_METADATA_REMAP)
1183
1184#define BTRFS_BLOCK_GROUP_PROFILE_MASK (BTRFS_BLOCK_GROUP_RAID0 | \
1185 BTRFS_BLOCK_GROUP_RAID1 | \
1186 BTRFS_BLOCK_GROUP_RAID1C3 | \
1187 BTRFS_BLOCK_GROUP_RAID1C4 | \
1188 BTRFS_BLOCK_GROUP_RAID5 | \
1189 BTRFS_BLOCK_GROUP_RAID6 | \
1190 BTRFS_BLOCK_GROUP_DUP | \
1191 BTRFS_BLOCK_GROUP_RAID10)
1192#define BTRFS_BLOCK_GROUP_RAID56_MASK (BTRFS_BLOCK_GROUP_RAID5 | \
1193 BTRFS_BLOCK_GROUP_RAID6)
1194
1195#define BTRFS_BLOCK_GROUP_RAID1_MASK (BTRFS_BLOCK_GROUP_RAID1 | \
1196 BTRFS_BLOCK_GROUP_RAID1C3 | \
1197 BTRFS_BLOCK_GROUP_RAID1C4)
1198
1199/*
1200 * We need a bit for restriper to be able to tell when chunks of type
1201 * SINGLE are available. This "extended" profile format is used in
1202 * fs_info->avail_*_alloc_bits (in-memory) and balance item fields
1203 * (on-disk). The corresponding on-disk bit in chunk.type is reserved
1204 * to avoid remappings between two formats in future.
1205 */
1206#define BTRFS_AVAIL_ALLOC_BIT_SINGLE (1ULL << 48)
1207
1208/*
1209 * A fake block group type that is used to communicate global block reserve
1210 * size to userspace via the SPACE_INFO ioctl.
1211 */
1212#define BTRFS_SPACE_INFO_GLOBAL_RSV (1ULL << 49)
1213
1214#define BTRFS_EXTENDED_PROFILE_MASK (BTRFS_BLOCK_GROUP_PROFILE_MASK | \
1215 BTRFS_AVAIL_ALLOC_BIT_SINGLE)
1216
1217static inline __u64 chunk_to_extended(__u64 flags)
1218{
1219 if ((flags & BTRFS_BLOCK_GROUP_PROFILE_MASK) == 0)
1220 flags |= BTRFS_AVAIL_ALLOC_BIT_SINGLE;
1221
1222 return flags;
1223}
1224static inline __u64 extended_to_chunk(__u64 flags)
1225{
1226 return flags & ~BTRFS_AVAIL_ALLOC_BIT_SINGLE;
1227}
1228
1229struct btrfs_block_group_item {
1230 __le64 used;
1231 __le64 chunk_objectid;
1232 __le64 flags;
1233} __attribute__ ((__packed__));
1234
1235struct btrfs_block_group_item_v2 {
1236 __le64 used;
1237 __le64 chunk_objectid;
1238 __le64 flags;
1239 __le64 remap_bytes;
1240 __le32 identity_remap_count;
1241} __attribute__ ((__packed__));
1242
1243struct btrfs_free_space_info {
1244 __le32 extent_count;
1245 __le32 flags;
1246} __attribute__ ((__packed__));
1247
1248#define BTRFS_FREE_SPACE_USING_BITMAPS (1UL << 0)
1249#define BTRFS_FREE_SPACE_FLAGS_MASK (BTRFS_FREE_SPACE_USING_BITMAPS)
1250
1251#define BTRFS_QGROUP_LEVEL_SHIFT 48
1252static inline __u16 btrfs_qgroup_level(__u64 qgroupid)
1253{
1254 return (__u16)(qgroupid >> BTRFS_QGROUP_LEVEL_SHIFT);
1255}
1256
1257/*
1258 * is subvolume quota turned on?
1259 */
1260#define BTRFS_QGROUP_STATUS_FLAG_ON (1ULL << 0)
1261/*
1262 * RESCAN is set during the initialization phase
1263 */
1264#define BTRFS_QGROUP_STATUS_FLAG_RESCAN (1ULL << 1)
1265/*
1266 * Some qgroup entries are known to be out of date,
1267 * either because the configuration has changed in a way that
1268 * makes a rescan necessary, or because the fs has been mounted
1269 * with a non-qgroup-aware version.
1270 * Turning qouta off and on again makes it inconsistent, too.
1271 */
1272#define BTRFS_QGROUP_STATUS_FLAG_INCONSISTENT (1ULL << 2)
1273
1274/*
1275 * Whether or not this filesystem is using simple quotas. Not exactly the
1276 * incompat bit, because we support using simple quotas, disabling it, then
1277 * going back to full qgroup quotas.
1278 */
1279#define BTRFS_QGROUP_STATUS_FLAG_SIMPLE_MODE (1ULL << 3)
1280
1281#define BTRFS_QGROUP_STATUS_FLAGS_MASK (BTRFS_QGROUP_STATUS_FLAG_ON | \
1282 BTRFS_QGROUP_STATUS_FLAG_RESCAN | \
1283 BTRFS_QGROUP_STATUS_FLAG_INCONSISTENT | \
1284 BTRFS_QGROUP_STATUS_FLAG_SIMPLE_MODE)
1285
1286#define BTRFS_QGROUP_STATUS_VERSION 1
1287
1288struct btrfs_qgroup_status_item {
1289 __le64 version;
1290 /*
1291 * the generation is updated during every commit. As older
1292 * versions of btrfs are not aware of qgroups, it will be
1293 * possible to detect inconsistencies by checking the
1294 * generation on mount time
1295 */
1296 __le64 generation;
1297
1298 /* flag definitions see above */
1299 __le64 flags;
1300
1301 /*
1302 * only used during scanning to record the progress
1303 * of the scan. It contains a logical address
1304 */
1305 __le64 rescan;
1306
1307 /*
1308 * The generation when quotas were last enabled. Used by simple quotas to
1309 * avoid decrementing when freeing an extent that was written before
1310 * enable.
1311 *
1312 * Set only if flags contain BTRFS_QGROUP_STATUS_FLAG_SIMPLE_MODE.
1313 */
1314 __le64 enable_gen;
1315} __attribute__ ((__packed__));
1316
1317struct btrfs_qgroup_info_item {
1318 __le64 generation;
1319 __le64 rfer;
1320 __le64 rfer_cmpr;
1321 __le64 excl;
1322 __le64 excl_cmpr;
1323} __attribute__ ((__packed__));
1324
1325struct btrfs_qgroup_limit_item {
1326 /*
1327 * only updated when any of the other values change
1328 */
1329 __le64 flags;
1330 __le64 max_rfer;
1331 __le64 max_excl;
1332 __le64 rsv_rfer;
1333 __le64 rsv_excl;
1334} __attribute__ ((__packed__));
1335
1336struct btrfs_verity_descriptor_item {
1337 /* Size of the verity descriptor in bytes */
1338 __le64 size;
1339 /*
1340 * When we implement support for fscrypt, we will need to encrypt the
1341 * Merkle tree for encrypted verity files. These 128 bits are for the
1342 * eventual storage of an fscrypt initialization vector.
1343 */
1344 __le64 reserved[2];
1345 __u8 encryption;
1346} __attribute__ ((__packed__));
1347
1348/*
1349 * For a range identified by a BTRFS_REMAP_KEY item in the remap tree, gives
1350 * the address that the start of the range will get remapped to. This
1351 * structure is also shared by BTRFS_REMAP_BACKREF_KEY.
1352 */
1353struct btrfs_remap_item {
1354 __le64 address;
1355} __attribute__ ((__packed__));
1356
1357#endif /* _BTRFS_CTREE_H_ */