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