Line data Source code
1 : /* SPDX-License-Identifier: GPL-2.0 */
2 : /*
3 : * Copyright (c) 2000-2001,2005 Silicon Graphics, Inc.
4 : * Copyright (c) 2013 Red Hat, Inc.
5 : * All Rights Reserved.
6 : */
7 : #ifndef __XFS_DA_FORMAT_H__
8 : #define __XFS_DA_FORMAT_H__
9 :
10 : /*
11 : * This structure is common to both leaf nodes and non-leaf nodes in the Btree.
12 : *
13 : * It is used to manage a doubly linked list of all blocks at the same
14 : * level in the Btree, and to identify which type of block this is.
15 : */
16 : #define XFS_DA_NODE_MAGIC 0xfebe /* magic number: non-leaf blocks */
17 : #define XFS_ATTR_LEAF_MAGIC 0xfbee /* magic number: attribute leaf blks */
18 : #define XFS_DIR2_LEAF1_MAGIC 0xd2f1 /* magic number: v2 dirlf single blks */
19 : #define XFS_DIR2_LEAFN_MAGIC 0xd2ff /* magic number: v2 dirlf multi blks */
20 :
21 : typedef struct xfs_da_blkinfo {
22 : __be32 forw; /* previous block in list */
23 : __be32 back; /* following block in list */
24 : __be16 magic; /* validity check on block */
25 : __be16 pad; /* unused */
26 : } xfs_da_blkinfo_t;
27 :
28 : /*
29 : * CRC enabled directory structure types
30 : *
31 : * The headers change size for the additional verification information, but
32 : * otherwise the tree layouts and contents are unchanged. Hence the da btree
33 : * code can use the struct xfs_da_blkinfo for manipulating the tree links and
34 : * magic numbers without modification for both v2 and v3 nodes.
35 : */
36 : #define XFS_DA3_NODE_MAGIC 0x3ebe /* magic number: non-leaf blocks */
37 : #define XFS_ATTR3_LEAF_MAGIC 0x3bee /* magic number: attribute leaf blks */
38 : #define XFS_DIR3_LEAF1_MAGIC 0x3df1 /* magic number: v3 dirlf single blks */
39 : #define XFS_DIR3_LEAFN_MAGIC 0x3dff /* magic number: v3 dirlf multi blks */
40 :
41 : struct xfs_da3_blkinfo {
42 : /*
43 : * the node link manipulation code relies on the fact that the first
44 : * element of this structure is the struct xfs_da_blkinfo so it can
45 : * ignore the differences in the rest of the structures.
46 : */
47 : struct xfs_da_blkinfo hdr;
48 : __be32 crc; /* CRC of block */
49 : __be64 blkno; /* first block of the buffer */
50 : __be64 lsn; /* sequence number of last write */
51 : uuid_t uuid; /* filesystem we belong to */
52 : __be64 owner; /* inode that owns the block */
53 : };
54 :
55 : /*
56 : * This is the structure of the root and intermediate nodes in the Btree.
57 : * The leaf nodes are defined above.
58 : *
59 : * Entries are not packed.
60 : *
61 : * Since we have duplicate keys, use a binary search but always follow
62 : * all match in the block, not just the first match found.
63 : */
64 : #define XFS_DA_NODE_MAXDEPTH 5 /* max depth of Btree */
65 :
66 : typedef struct xfs_da_node_hdr {
67 : struct xfs_da_blkinfo info; /* block type, links, etc. */
68 : __be16 __count; /* count of active entries */
69 : __be16 __level; /* level above leaves (leaf == 0) */
70 : } xfs_da_node_hdr_t;
71 :
72 : struct xfs_da3_node_hdr {
73 : struct xfs_da3_blkinfo info; /* block type, links, etc. */
74 : __be16 __count; /* count of active entries */
75 : __be16 __level; /* level above leaves (leaf == 0) */
76 : __be32 __pad32;
77 : };
78 :
79 : #define XFS_DA3_NODE_CRC_OFF (offsetof(struct xfs_da3_node_hdr, info.crc))
80 :
81 : typedef struct xfs_da_node_entry {
82 : __be32 hashval; /* hash value for this descendant */
83 : __be32 before; /* Btree block before this key */
84 : } xfs_da_node_entry_t;
85 :
86 : typedef struct xfs_da_intnode {
87 : struct xfs_da_node_hdr hdr;
88 : struct xfs_da_node_entry __btree[];
89 : } xfs_da_intnode_t;
90 :
91 : struct xfs_da3_intnode {
92 : struct xfs_da3_node_hdr hdr;
93 : struct xfs_da_node_entry __btree[];
94 : };
95 :
96 : /*
97 : * Directory version 2.
98 : *
99 : * There are 4 possible formats:
100 : * - shortform - embedded into the inode
101 : * - single block - data with embedded leaf at the end
102 : * - multiple data blocks, single leaf+freeindex block
103 : * - data blocks, node and leaf blocks (btree), freeindex blocks
104 : *
105 : * Note: many node blocks structures and constants are shared with the attr
106 : * code and defined in xfs_da_btree.h.
107 : */
108 :
109 : #define XFS_DIR2_BLOCK_MAGIC 0x58443242 /* XD2B: single block dirs */
110 : #define XFS_DIR2_DATA_MAGIC 0x58443244 /* XD2D: multiblock dirs */
111 : #define XFS_DIR2_FREE_MAGIC 0x58443246 /* XD2F: free index blocks */
112 :
113 : /*
114 : * Directory Version 3 With CRCs.
115 : *
116 : * The tree formats are the same as for version 2 directories. The difference
117 : * is in the block header and dirent formats. In many cases the v3 structures
118 : * use v2 definitions as they are no different and this makes code sharing much
119 : * easier.
120 : *
121 : * Also, the xfs_dir3_*() functions handle both v2 and v3 formats - if the
122 : * format is v2 then they switch to the existing v2 code, or the format is v3
123 : * they implement the v3 functionality. This means the existing dir2 is a mix of
124 : * xfs_dir2/xfs_dir3 calls and functions. The xfs_dir3 functions are called
125 : * where there is a difference in the formats, otherwise the code is unchanged.
126 : *
127 : * Where it is possible, the code decides what to do based on the magic numbers
128 : * in the blocks rather than feature bits in the superblock. This means the code
129 : * is as independent of the external XFS code as possible as doesn't require
130 : * passing struct xfs_mount pointers into places where it isn't really
131 : * necessary.
132 : *
133 : * Version 3 includes:
134 : *
135 : * - a larger block header for CRC and identification purposes and so the
136 : * offsets of all the structures inside the blocks are different.
137 : *
138 : * - new magic numbers to be able to detect the v2/v3 types on the fly.
139 : */
140 :
141 : #define XFS_DIR3_BLOCK_MAGIC 0x58444233 /* XDB3: single block dirs */
142 : #define XFS_DIR3_DATA_MAGIC 0x58444433 /* XDD3: multiblock dirs */
143 : #define XFS_DIR3_FREE_MAGIC 0x58444633 /* XDF3: free index blocks */
144 :
145 : /*
146 : * Dirents in version 3 directories have a file type field. Additions to this
147 : * list are an on-disk format change, requiring feature bits. Valid values
148 : * are as follows:
149 : */
150 : #define XFS_DIR3_FT_UNKNOWN 0
151 : #define XFS_DIR3_FT_REG_FILE 1
152 : #define XFS_DIR3_FT_DIR 2
153 : #define XFS_DIR3_FT_CHRDEV 3
154 : #define XFS_DIR3_FT_BLKDEV 4
155 : #define XFS_DIR3_FT_FIFO 5
156 : #define XFS_DIR3_FT_SOCK 6
157 : #define XFS_DIR3_FT_SYMLINK 7
158 : #define XFS_DIR3_FT_WHT 8
159 :
160 : #define XFS_DIR3_FT_MAX 9
161 :
162 : #define XFS_DIR3_FTYPE_STR \
163 : { XFS_DIR3_FT_UNKNOWN, "unknown" }, \
164 : { XFS_DIR3_FT_REG_FILE, "file" }, \
165 : { XFS_DIR3_FT_DIR, "directory" }, \
166 : { XFS_DIR3_FT_CHRDEV, "char" }, \
167 : { XFS_DIR3_FT_BLKDEV, "block" }, \
168 : { XFS_DIR3_FT_FIFO, "fifo" }, \
169 : { XFS_DIR3_FT_SOCK, "sock" }, \
170 : { XFS_DIR3_FT_SYMLINK, "symlink" }, \
171 : { XFS_DIR3_FT_WHT, "whiteout" }
172 :
173 : /*
174 : * Byte offset in data block and shortform entry.
175 : */
176 : typedef uint16_t xfs_dir2_data_off_t;
177 : #define NULLDATAOFF 0xffffU
178 : typedef uint xfs_dir2_data_aoff_t; /* argument form */
179 :
180 : /*
181 : * Offset in data space of a data entry.
182 : */
183 : typedef uint32_t xfs_dir2_dataptr_t;
184 : #define XFS_DIR2_MAX_DATAPTR ((xfs_dir2_dataptr_t)0xffffffff)
185 : #define XFS_DIR2_NULL_DATAPTR ((xfs_dir2_dataptr_t)0)
186 :
187 : /*
188 : * Byte offset in a directory.
189 : */
190 : typedef xfs_off_t xfs_dir2_off_t;
191 :
192 : /*
193 : * Directory block number (logical dirblk in file)
194 : */
195 : typedef uint32_t xfs_dir2_db_t;
196 :
197 : #define XFS_INO32_SIZE 4
198 : #define XFS_INO64_SIZE 8
199 : #define XFS_INO64_DIFF (XFS_INO64_SIZE - XFS_INO32_SIZE)
200 :
201 : #define XFS_DIR2_MAX_SHORT_INUM ((xfs_ino_t)0xffffffffULL)
202 :
203 : /*
204 : * Directory layout when stored internal to an inode.
205 : *
206 : * Small directories are packed as tightly as possible so as to fit into the
207 : * literal area of the inode. These "shortform" directories consist of a
208 : * single xfs_dir2_sf_hdr header followed by zero or more xfs_dir2_sf_entry
209 : * structures. Due the different inode number storage size and the variable
210 : * length name field in the xfs_dir2_sf_entry all these structure are
211 : * variable length, and the accessors in this file should be used to iterate
212 : * over them.
213 : */
214 : typedef struct xfs_dir2_sf_hdr {
215 : uint8_t count; /* count of entries */
216 : uint8_t i8count; /* count of 8-byte inode #s */
217 : uint8_t parent[8]; /* parent dir inode number */
218 : } __packed xfs_dir2_sf_hdr_t;
219 :
220 : typedef struct xfs_dir2_sf_entry {
221 : __u8 namelen; /* actual name length */
222 : __u8 offset[2]; /* saved offset */
223 : __u8 name[]; /* name, variable size */
224 : /*
225 : * A single byte containing the file type field follows the inode
226 : * number for version 3 directory entries.
227 : *
228 : * A 64-bit or 32-bit inode number follows here, at a variable offset
229 : * after the name.
230 : */
231 : } __packed xfs_dir2_sf_entry_t;
232 :
233 : static inline int xfs_dir2_sf_hdr_size(int i8count)
234 : {
235 6721701696 : return sizeof(struct xfs_dir2_sf_hdr) -
236 : (i8count == 0) * XFS_INO64_DIFF;
237 : }
238 :
239 : static inline xfs_dir2_data_aoff_t
240 : xfs_dir2_sf_get_offset(xfs_dir2_sf_entry_t *sfep)
241 : {
242 24298376412 : return get_unaligned_be16(sfep->offset);
243 : }
244 :
245 : static inline void
246 : xfs_dir2_sf_put_offset(xfs_dir2_sf_entry_t *sfep, xfs_dir2_data_aoff_t off)
247 : {
248 94509509 : put_unaligned_be16(off, sfep->offset);
249 : }
250 :
251 : static inline struct xfs_dir2_sf_entry *
252 : xfs_dir2_sf_firstentry(struct xfs_dir2_sf_hdr *hdr)
253 : {
254 12405034530 : return (struct xfs_dir2_sf_entry *)
255 7180413395 : ((char *)hdr + xfs_dir2_sf_hdr_size(hdr->i8count));
256 : }
257 :
258 : /*
259 : * Data block structures.
260 : *
261 : * A pure data block looks like the following drawing on disk:
262 : *
263 : * +-------------------------------------------------+
264 : * | xfs_dir2_data_hdr_t |
265 : * +-------------------------------------------------+
266 : * | xfs_dir2_data_entry_t OR xfs_dir2_data_unused_t |
267 : * | xfs_dir2_data_entry_t OR xfs_dir2_data_unused_t |
268 : * | xfs_dir2_data_entry_t OR xfs_dir2_data_unused_t |
269 : * | ... |
270 : * +-------------------------------------------------+
271 : * | unused space |
272 : * +-------------------------------------------------+
273 : *
274 : * As all the entries are variable size structures the accessors below should
275 : * be used to iterate over them.
276 : *
277 : * In addition to the pure data blocks for the data and node formats,
278 : * most structures are also used for the combined data/freespace "block"
279 : * format below.
280 : */
281 :
282 : #define XFS_DIR2_DATA_ALIGN_LOG 3 /* i.e., 8 bytes */
283 : #define XFS_DIR2_DATA_ALIGN (1 << XFS_DIR2_DATA_ALIGN_LOG)
284 : #define XFS_DIR2_DATA_FREE_TAG 0xffff
285 : #define XFS_DIR2_DATA_FD_COUNT 3
286 :
287 : /*
288 : * Directory address space divided into sections,
289 : * spaces separated by 32GB.
290 : */
291 : #define XFS_DIR2_MAX_SPACES 3
292 : #define XFS_DIR2_SPACE_SIZE (1ULL << (32 + XFS_DIR2_DATA_ALIGN_LOG))
293 : #define XFS_DIR2_DATA_SPACE 0
294 : #define XFS_DIR2_DATA_OFFSET (XFS_DIR2_DATA_SPACE * XFS_DIR2_SPACE_SIZE)
295 :
296 : /*
297 : * Describe a free area in the data block.
298 : *
299 : * The freespace will be formatted as a xfs_dir2_data_unused_t.
300 : */
301 : typedef struct xfs_dir2_data_free {
302 : __be16 offset; /* start of freespace */
303 : __be16 length; /* length of freespace */
304 : } xfs_dir2_data_free_t;
305 :
306 : /*
307 : * Header for the data blocks.
308 : *
309 : * The code knows that XFS_DIR2_DATA_FD_COUNT is 3.
310 : */
311 : typedef struct xfs_dir2_data_hdr {
312 : __be32 magic; /* XFS_DIR2_DATA_MAGIC or */
313 : /* XFS_DIR2_BLOCK_MAGIC */
314 : xfs_dir2_data_free_t bestfree[XFS_DIR2_DATA_FD_COUNT];
315 : } xfs_dir2_data_hdr_t;
316 :
317 : /*
318 : * define a structure for all the verification fields we are adding to the
319 : * directory block structures. This will be used in several structures.
320 : * The magic number must be the first entry to align with all the dir2
321 : * structures so we determine how to decode them just by the magic number.
322 : */
323 : struct xfs_dir3_blk_hdr {
324 : __be32 magic; /* magic number */
325 : __be32 crc; /* CRC of block */
326 : __be64 blkno; /* first block of the buffer */
327 : __be64 lsn; /* sequence number of last write */
328 : uuid_t uuid; /* filesystem we belong to */
329 : __be64 owner; /* inode that owns the block */
330 : };
331 :
332 : struct xfs_dir3_data_hdr {
333 : struct xfs_dir3_blk_hdr hdr;
334 : xfs_dir2_data_free_t best_free[XFS_DIR2_DATA_FD_COUNT];
335 : __be32 pad; /* 64 bit alignment */
336 : };
337 :
338 : #define XFS_DIR3_DATA_CRC_OFF offsetof(struct xfs_dir3_data_hdr, hdr.crc)
339 :
340 : /*
341 : * Active entry in a data block.
342 : *
343 : * Aligned to 8 bytes. After the variable length name field there is a
344 : * 2 byte tag field, which can be accessed using xfs_dir3_data_entry_tag_p.
345 : *
346 : * For dir3 structures, there is file type field between the name and the tag.
347 : * This can only be manipulated by helper functions. It is packed hard against
348 : * the end of the name so any padding for rounding is between the file type and
349 : * the tag.
350 : */
351 : typedef struct xfs_dir2_data_entry {
352 : __be64 inumber; /* inode number */
353 : __u8 namelen; /* name length */
354 : __u8 name[]; /* name bytes, no null */
355 : /* __u8 filetype; */ /* type of inode we point to */
356 : /* __be16 tag; */ /* starting offset of us */
357 : } xfs_dir2_data_entry_t;
358 :
359 : /*
360 : * Unused entry in a data block.
361 : *
362 : * Aligned to 8 bytes. Tag appears as the last 2 bytes and must be accessed
363 : * using xfs_dir2_data_unused_tag_p.
364 : */
365 : typedef struct xfs_dir2_data_unused {
366 : __be16 freetag; /* XFS_DIR2_DATA_FREE_TAG */
367 : __be16 length; /* total free length */
368 : /* variable offset */
369 : __be16 tag; /* starting offset of us */
370 : } xfs_dir2_data_unused_t;
371 :
372 : /*
373 : * Pointer to a freespace's tag word.
374 : */
375 : static inline __be16 *
376 : xfs_dir2_data_unused_tag_p(struct xfs_dir2_data_unused *dup)
377 : {
378 5506627413 : return (__be16 *)((char *)dup +
379 5506627413 : be16_to_cpu(dup->length) - sizeof(__be16));
380 : }
381 :
382 : /*
383 : * Leaf block structures.
384 : *
385 : * A pure leaf block looks like the following drawing on disk:
386 : *
387 : * +---------------------------+
388 : * | xfs_dir2_leaf_hdr_t |
389 : * +---------------------------+
390 : * | xfs_dir2_leaf_entry_t |
391 : * | xfs_dir2_leaf_entry_t |
392 : * | xfs_dir2_leaf_entry_t |
393 : * | xfs_dir2_leaf_entry_t |
394 : * | ... |
395 : * +---------------------------+
396 : * | xfs_dir2_data_off_t |
397 : * | xfs_dir2_data_off_t |
398 : * | xfs_dir2_data_off_t |
399 : * | ... |
400 : * +---------------------------+
401 : * | xfs_dir2_leaf_tail_t |
402 : * +---------------------------+
403 : *
404 : * The xfs_dir2_data_off_t members (bests) and tail are at the end of the block
405 : * for single-leaf (magic = XFS_DIR2_LEAF1_MAGIC) blocks only, but not present
406 : * for directories with separate leaf nodes and free space blocks
407 : * (magic = XFS_DIR2_LEAFN_MAGIC).
408 : *
409 : * As all the entries are variable size structures the accessors below should
410 : * be used to iterate over them.
411 : */
412 :
413 : /*
414 : * Offset of the leaf/node space. First block in this space
415 : * is the btree root.
416 : */
417 : #define XFS_DIR2_LEAF_SPACE 1
418 : #define XFS_DIR2_LEAF_OFFSET (XFS_DIR2_LEAF_SPACE * XFS_DIR2_SPACE_SIZE)
419 :
420 : /*
421 : * Leaf block header.
422 : */
423 : typedef struct xfs_dir2_leaf_hdr {
424 : xfs_da_blkinfo_t info; /* header for da routines */
425 : __be16 count; /* count of entries */
426 : __be16 stale; /* count of stale entries */
427 : } xfs_dir2_leaf_hdr_t;
428 :
429 : struct xfs_dir3_leaf_hdr {
430 : struct xfs_da3_blkinfo info; /* header for da routines */
431 : __be16 count; /* count of entries */
432 : __be16 stale; /* count of stale entries */
433 : __be32 pad; /* 64 bit alignment */
434 : };
435 :
436 : /*
437 : * Leaf block entry.
438 : */
439 : typedef struct xfs_dir2_leaf_entry {
440 : __be32 hashval; /* hash value of name */
441 : __be32 address; /* address of data entry */
442 : } xfs_dir2_leaf_entry_t;
443 :
444 : /*
445 : * Leaf block tail.
446 : */
447 : typedef struct xfs_dir2_leaf_tail {
448 : __be32 bestcount;
449 : } xfs_dir2_leaf_tail_t;
450 :
451 : /*
452 : * Leaf block.
453 : */
454 : typedef struct xfs_dir2_leaf {
455 : xfs_dir2_leaf_hdr_t hdr; /* leaf header */
456 : xfs_dir2_leaf_entry_t __ents[]; /* entries */
457 : } xfs_dir2_leaf_t;
458 :
459 : struct xfs_dir3_leaf {
460 : struct xfs_dir3_leaf_hdr hdr; /* leaf header */
461 : struct xfs_dir2_leaf_entry __ents[]; /* entries */
462 : };
463 :
464 : #define XFS_DIR3_LEAF_CRC_OFF offsetof(struct xfs_dir3_leaf_hdr, info.crc)
465 :
466 : /*
467 : * Get address of the bests array in the single-leaf block.
468 : */
469 : static inline __be16 *
470 : xfs_dir2_leaf_bests_p(struct xfs_dir2_leaf_tail *ltp)
471 : {
472 120171750 : return (__be16 *)ltp - be32_to_cpu(ltp->bestcount);
473 : }
474 :
475 : /*
476 : * Free space block definitions for the node format.
477 : */
478 :
479 : /*
480 : * Offset of the freespace index.
481 : */
482 : #define XFS_DIR2_FREE_SPACE 2
483 : #define XFS_DIR2_FREE_OFFSET (XFS_DIR2_FREE_SPACE * XFS_DIR2_SPACE_SIZE)
484 :
485 : typedef struct xfs_dir2_free_hdr {
486 : __be32 magic; /* XFS_DIR2_FREE_MAGIC */
487 : __be32 firstdb; /* db of first entry */
488 : __be32 nvalid; /* count of valid entries */
489 : __be32 nused; /* count of used entries */
490 : } xfs_dir2_free_hdr_t;
491 :
492 : typedef struct xfs_dir2_free {
493 : xfs_dir2_free_hdr_t hdr; /* block header */
494 : __be16 bests[]; /* best free counts */
495 : /* unused entries are -1 */
496 : } xfs_dir2_free_t;
497 :
498 : struct xfs_dir3_free_hdr {
499 : struct xfs_dir3_blk_hdr hdr;
500 : __be32 firstdb; /* db of first entry */
501 : __be32 nvalid; /* count of valid entries */
502 : __be32 nused; /* count of used entries */
503 : __be32 pad; /* 64 bit alignment */
504 : };
505 :
506 : struct xfs_dir3_free {
507 : struct xfs_dir3_free_hdr hdr;
508 : __be16 bests[]; /* best free counts */
509 : /* unused entries are -1 */
510 : };
511 :
512 : #define XFS_DIR3_FREE_CRC_OFF offsetof(struct xfs_dir3_free, hdr.hdr.crc)
513 :
514 : /*
515 : * Single block format.
516 : *
517 : * The single block format looks like the following drawing on disk:
518 : *
519 : * +-------------------------------------------------+
520 : * | xfs_dir2_data_hdr_t |
521 : * +-------------------------------------------------+
522 : * | xfs_dir2_data_entry_t OR xfs_dir2_data_unused_t |
523 : * | xfs_dir2_data_entry_t OR xfs_dir2_data_unused_t |
524 : * | xfs_dir2_data_entry_t OR xfs_dir2_data_unused_t :
525 : * | ... |
526 : * +-------------------------------------------------+
527 : * | unused space |
528 : * +-------------------------------------------------+
529 : * | ... |
530 : * | xfs_dir2_leaf_entry_t |
531 : * | xfs_dir2_leaf_entry_t |
532 : * +-------------------------------------------------+
533 : * | xfs_dir2_block_tail_t |
534 : * +-------------------------------------------------+
535 : *
536 : * As all the entries are variable size structures the accessors below should
537 : * be used to iterate over them.
538 : */
539 :
540 : typedef struct xfs_dir2_block_tail {
541 : __be32 count; /* count of leaf entries */
542 : __be32 stale; /* count of stale lf entries */
543 : } xfs_dir2_block_tail_t;
544 :
545 : /*
546 : * Pointer to the leaf entries embedded in a data block (1-block format)
547 : */
548 : static inline struct xfs_dir2_leaf_entry *
549 : xfs_dir2_block_leaf_p(struct xfs_dir2_block_tail *btp)
550 : {
551 429332223 : return ((struct xfs_dir2_leaf_entry *)btp) - be32_to_cpu(btp->count);
552 : }
553 :
554 :
555 : /*
556 : * Attribute storage layout
557 : *
558 : * Attribute lists are structured around Btrees where all the data
559 : * elements are in the leaf nodes. Attribute names are hashed into an int,
560 : * then that int is used as the index into the Btree. Since the hashval
561 : * of an attribute name may not be unique, we may have duplicate keys. The
562 : * internal links in the Btree are logical block offsets into the file.
563 : *
564 : * Struct leaf_entry's are packed from the top. Name/values grow from the
565 : * bottom but are not packed. The freemap contains run-length-encoded entries
566 : * for the free bytes after the leaf_entry's, but only the N largest such,
567 : * smaller runs are dropped. When the freemap doesn't show enough space
568 : * for an allocation, we compact the name/value area and try again. If we
569 : * still don't have enough space, then we have to split the block. The
570 : * name/value structs (both local and remote versions) must be 32bit aligned.
571 : *
572 : * Since we have duplicate hash keys, for each key that matches, compare
573 : * the actual name string. The root and intermediate node search always
574 : * takes the first-in-the-block key match found, so we should only have
575 : * to work "forw"ard. If none matches, continue with the "forw"ard leaf
576 : * nodes until the hash key changes or the attribute name is found.
577 : *
578 : * We store the fact that an attribute is a ROOT/USER/SECURE attribute in
579 : * the leaf_entry. The namespaces are independent only because we also look
580 : * at the namespace bit when we are looking for a matching attribute name.
581 : *
582 : * We also store an "incomplete" bit in the leaf_entry. It shows that an
583 : * attribute is in the middle of being created and should not be shown to
584 : * the user if we crash during the time that the bit is set. We clear the
585 : * bit when we have finished setting up the attribute. We do this because
586 : * we cannot create some large attributes inside a single transaction, and we
587 : * need some indication that we weren't finished if we crash in the middle.
588 : */
589 : #define XFS_ATTR_LEAF_MAPSIZE 3 /* how many freespace slots */
590 :
591 : /*
592 : * Entries are packed toward the top as tight as possible.
593 : */
594 : struct xfs_attr_shortform {
595 : struct xfs_attr_sf_hdr { /* constant-structure header block */
596 : __be16 totsize; /* total bytes in shortform list */
597 : __u8 count; /* count of active entries */
598 : __u8 padding;
599 : } hdr;
600 : struct xfs_attr_sf_entry {
601 : uint8_t namelen; /* actual length of name (no NULL) */
602 : uint8_t valuelen; /* actual length of value (no NULL) */
603 : uint8_t flags; /* flags bits (see xfs_attr_leaf.h) */
604 : uint8_t nameval[]; /* name & value bytes concatenated */
605 : } list[]; /* variable sized array */
606 : };
607 :
608 : typedef struct xfs_attr_leaf_map { /* RLE map of free bytes */
609 : __be16 base; /* base of free region */
610 : __be16 size; /* length of free region */
611 : } xfs_attr_leaf_map_t;
612 :
613 : typedef struct xfs_attr_leaf_hdr { /* constant-structure header block */
614 : xfs_da_blkinfo_t info; /* block type, links, etc. */
615 : __be16 count; /* count of active leaf_entry's */
616 : __be16 usedbytes; /* num bytes of names/values stored */
617 : __be16 firstused; /* first used byte in name area */
618 : __u8 holes; /* != 0 if blk needs compaction */
619 : __u8 pad1;
620 : xfs_attr_leaf_map_t freemap[XFS_ATTR_LEAF_MAPSIZE];
621 : /* N largest free regions */
622 : } xfs_attr_leaf_hdr_t;
623 :
624 : typedef struct xfs_attr_leaf_entry { /* sorted on key, not name */
625 : __be32 hashval; /* hash value of name */
626 : __be16 nameidx; /* index into buffer of name/value */
627 : __u8 flags; /* LOCAL/ROOT/SECURE/INCOMPLETE flag */
628 : __u8 pad2; /* unused pad byte */
629 : } xfs_attr_leaf_entry_t;
630 :
631 : typedef struct xfs_attr_leaf_name_local {
632 : __be16 valuelen; /* number of bytes in value */
633 : __u8 namelen; /* length of name bytes */
634 : /*
635 : * In Linux 6.5 this flex array was converted from nameval[1] to
636 : * nameval[]. Be very careful here about extra padding at the end;
637 : * see xfs_attr_leaf_entsize_local() for details.
638 : */
639 : __u8 nameval[]; /* name/value bytes */
640 : } xfs_attr_leaf_name_local_t;
641 :
642 : typedef struct xfs_attr_leaf_name_remote {
643 : __be32 valueblk; /* block number of value bytes */
644 : __be32 valuelen; /* number of bytes in value */
645 : __u8 namelen; /* length of name bytes */
646 : /*
647 : * In Linux 6.5 this flex array was converted from name[1] to name[].
648 : * Be very careful here about extra padding at the end; see
649 : * xfs_attr_leaf_entsize_remote() for details.
650 : */
651 : __u8 name[]; /* name bytes */
652 : } xfs_attr_leaf_name_remote_t;
653 :
654 : typedef struct xfs_attr_leafblock {
655 : xfs_attr_leaf_hdr_t hdr; /* constant-structure header block */
656 : xfs_attr_leaf_entry_t entries[]; /* sorted on key, not name */
657 : /*
658 : * The rest of the block contains the following structures after the
659 : * leaf entries, growing from the bottom up. The variables are never
660 : * referenced and definining them can actually make gcc optimize away
661 : * accesses to the 'entries' array above index 0 so don't do that.
662 : *
663 : * xfs_attr_leaf_name_local_t namelist;
664 : * xfs_attr_leaf_name_remote_t valuelist;
665 : */
666 : } xfs_attr_leafblock_t;
667 :
668 : /*
669 : * CRC enabled leaf structures. Called "version 3" structures to match the
670 : * version number of the directory and dablk structures for this feature, and
671 : * attr2 is already taken by the variable inode attribute fork size feature.
672 : */
673 : struct xfs_attr3_leaf_hdr {
674 : struct xfs_da3_blkinfo info;
675 : __be16 count;
676 : __be16 usedbytes;
677 : __be16 firstused;
678 : __u8 holes;
679 : __u8 pad1;
680 : struct xfs_attr_leaf_map freemap[XFS_ATTR_LEAF_MAPSIZE];
681 : __be32 pad2; /* 64 bit alignment */
682 : };
683 :
684 : #define XFS_ATTR3_LEAF_CRC_OFF (offsetof(struct xfs_attr3_leaf_hdr, info.crc))
685 :
686 : struct xfs_attr3_leafblock {
687 : struct xfs_attr3_leaf_hdr hdr;
688 : struct xfs_attr_leaf_entry entries[];
689 :
690 : /*
691 : * The rest of the block contains the following structures after the
692 : * leaf entries, growing from the bottom up. The variables are never
693 : * referenced, the locations accessed purely from helper functions.
694 : *
695 : * struct xfs_attr_leaf_name_local
696 : * struct xfs_attr_leaf_name_remote
697 : */
698 : };
699 :
700 : /*
701 : * Special value to represent fs block size in the leaf header firstused field.
702 : * Only used when block size overflows the 2-bytes available on disk.
703 : */
704 : #define XFS_ATTR3_LEAF_NULLOFF 0
705 :
706 : /*
707 : * Flags used in the leaf_entry[i].flags field.
708 : */
709 : #define XFS_ATTR_LOCAL_BIT 0 /* attr is stored locally */
710 : #define XFS_ATTR_ROOT_BIT 1 /* limit access to trusted attrs */
711 : #define XFS_ATTR_SECURE_BIT 2 /* limit access to secure attrs */
712 : #define XFS_ATTR_PARENT_BIT 3 /* parent pointer attrs */
713 : #define XFS_ATTR_INCOMPLETE_BIT 7 /* attr in middle of create/delete */
714 : #define XFS_ATTR_LOCAL (1u << XFS_ATTR_LOCAL_BIT)
715 : #define XFS_ATTR_ROOT (1u << XFS_ATTR_ROOT_BIT)
716 : #define XFS_ATTR_SECURE (1u << XFS_ATTR_SECURE_BIT)
717 : #define XFS_ATTR_PARENT (1u << XFS_ATTR_PARENT_BIT)
718 : #define XFS_ATTR_INCOMPLETE (1u << XFS_ATTR_INCOMPLETE_BIT)
719 : #define XFS_ATTR_NSP_ONDISK_MASK \
720 : (XFS_ATTR_ROOT | XFS_ATTR_SECURE | XFS_ATTR_PARENT)
721 :
722 : #define XFS_ATTR_NAMESPACE_STR \
723 : { XFS_ATTR_LOCAL, "local" }, \
724 : { XFS_ATTR_ROOT, "root" }, \
725 : { XFS_ATTR_SECURE, "secure" }
726 :
727 : /*
728 : * Alignment for namelist and valuelist entries (since they are mixed
729 : * there can be only one alignment value)
730 : */
731 : #define XFS_ATTR_LEAF_NAME_ALIGN ((uint)sizeof(xfs_dablk_t))
732 :
733 : static inline int
734 : xfs_attr3_leaf_hdr_size(struct xfs_attr_leafblock *leafp)
735 : {
736 1227725979 : if (leafp->hdr.info.magic == cpu_to_be16(XFS_ATTR3_LEAF_MAGIC))
737 1227759457 : return sizeof(struct xfs_attr3_leaf_hdr);
738 : return sizeof(struct xfs_attr_leaf_hdr);
739 : }
740 :
741 : static inline struct xfs_attr_leaf_entry *
742 : xfs_attr3_leaf_entryp(xfs_attr_leafblock_t *leafp)
743 : {
744 3636315987 : if (leafp->hdr.info.magic == cpu_to_be16(XFS_ATTR3_LEAF_MAGIC))
745 18186839773 : return &((struct xfs_attr3_leafblock *)leafp)->entries[0];
746 1884999 : return &leafp->entries[0];
747 : }
748 :
749 : /*
750 : * Cast typed pointers for "local" and "remote" name/value structs.
751 : */
752 : static inline char *
753 : xfs_attr3_leaf_name(xfs_attr_leafblock_t *leafp, int idx)
754 : {
755 8597866331 : struct xfs_attr_leaf_entry *entries = xfs_attr3_leaf_entryp(leafp);
756 :
757 14552398354 : return &((char *)leafp)[be16_to_cpu(entries[idx].nameidx)];
758 : }
759 :
760 : static inline int
761 : xfs_attr3_leaf_flags(xfs_attr_leafblock_t *leafp, int idx)
762 : {
763 : struct xfs_attr_leaf_entry *entries = xfs_attr3_leaf_entryp(leafp);
764 :
765 : return entries[idx].flags;
766 : }
767 :
768 : static inline xfs_attr_leaf_name_remote_t *
769 : xfs_attr3_leaf_name_remote(xfs_attr_leafblock_t *leafp, int idx)
770 : {
771 36141 : return (xfs_attr_leaf_name_remote_t *)xfs_attr3_leaf_name(leafp, idx);
772 : }
773 :
774 : static inline xfs_attr_leaf_name_local_t *
775 : xfs_attr3_leaf_name_local(xfs_attr_leafblock_t *leafp, int idx)
776 : {
777 16178271253 : return (xfs_attr_leaf_name_local_t *)xfs_attr3_leaf_name(leafp, idx);
778 : }
779 :
780 : /*
781 : * Calculate total bytes used (including trailing pad for alignment) for
782 : * a "local" name/value structure, a "remote" name/value structure, and
783 : * a pointer which might be either.
784 : */
785 : static inline int xfs_attr_leaf_entsize_remote(int nlen)
786 : {
787 : /*
788 : * Prior to Linux 6.5, struct xfs_attr_leaf_name_remote ended with
789 : * name[1], which was used as a flexarray. The layout of this struct
790 : * is 9 bytes of fixed-length fields followed by a __u8 flex array at
791 : * offset 9.
792 : *
793 : * On most architectures, struct xfs_attr_leaf_name_remote had two
794 : * bytes of implicit padding at the end of the struct to make the
795 : * struct length 12. After converting name[1] to name[], there are
796 : * three implicit padding bytes and the struct size remains 12.
797 : * However, there are compiler configurations that do not add implicit
798 : * padding at all (m68k) and have been broken for years.
799 : *
800 : * This entsize computation historically added (the xattr name length)
801 : * to (the padded struct length - 1) and rounded that sum up to the
802 : * nearest multiple of 4 (NAME_ALIGN). IOWs, round_up(11 + nlen, 4).
803 : * This is encoded in the ondisk format, so we cannot change this.
804 : *
805 : * Compute the entsize from offsetof of the flexarray and manually
806 : * adding bytes for the implicit padding.
807 : */
808 25740 : const size_t remotesize =
809 : offsetof(struct xfs_attr_leaf_name_remote, name) + 2;
810 :
811 25740 : return round_up(remotesize + nlen, XFS_ATTR_LEAF_NAME_ALIGN);
812 : }
813 :
814 : static inline int xfs_attr_leaf_entsize_local(int nlen, int vlen)
815 : {
816 : /*
817 : * Prior to Linux 6.5, struct xfs_attr_leaf_name_local ended with
818 : * nameval[1], which was used as a flexarray. The layout of this
819 : * struct is 3 bytes of fixed-length fields followed by a __u8 flex
820 : * array at offset 3.
821 : *
822 : * struct xfs_attr_leaf_name_local had zero bytes of implicit padding
823 : * at the end of the struct to make the struct length 4. On most
824 : * architectures, after converting nameval[1] to nameval[], there is
825 : * one implicit padding byte and the struct size remains 4. However,
826 : * there are compiler configurations that do not add implicit padding
827 : * at all (m68k) and would break.
828 : *
829 : * This entsize computation historically added (the xattr name and
830 : * value length) to (the padded struct length - 1) and rounded that sum
831 : * up to the nearest multiple of 4 (NAME_ALIGN). IOWs, the formula is
832 : * round_up(3 + nlen + vlen, 4). This is encoded in the ondisk format,
833 : * so we cannot change this.
834 : *
835 : * Compute the entsize from offsetof of the flexarray and manually
836 : * adding bytes for the implicit padding.
837 : */
838 2171032159 : const size_t localsize =
839 : offsetof(struct xfs_attr_leaf_name_local, nameval);
840 :
841 2171032159 : return round_up(localsize + nlen + vlen, XFS_ATTR_LEAF_NAME_ALIGN);
842 : }
843 :
844 : static inline int xfs_attr_leaf_entsize_local_max(int bsize)
845 : {
846 787621388 : return (((bsize) >> 1) + ((bsize) >> 2));
847 : }
848 :
849 :
850 :
851 : /*
852 : * Remote attribute block format definition
853 : *
854 : * There is one of these headers per filesystem block in a remote attribute.
855 : * This is done to ensure there is a 1:1 mapping between the attribute value
856 : * length and the number of blocks needed to store the attribute. This makes the
857 : * verification of a buffer a little more complex, but greatly simplifies the
858 : * allocation, reading and writing of these attributes as we don't have to guess
859 : * the number of blocks needed to store the attribute data.
860 : */
861 : #define XFS_ATTR3_RMT_MAGIC 0x5841524d /* XARM */
862 :
863 : struct xfs_attr3_rmt_hdr {
864 : __be32 rm_magic;
865 : __be32 rm_offset;
866 : __be32 rm_bytes;
867 : __be32 rm_crc;
868 : uuid_t rm_uuid;
869 : __be64 rm_owner;
870 : __be64 rm_blkno;
871 : __be64 rm_lsn;
872 : };
873 :
874 : #define XFS_ATTR3_RMT_CRC_OFF offsetof(struct xfs_attr3_rmt_hdr, rm_crc)
875 :
876 : #define XFS_ATTR3_RMT_BUF_SPACE(mp, bufsize) \
877 : ((bufsize) - (xfs_has_crc((mp)) ? \
878 : sizeof(struct xfs_attr3_rmt_hdr) : 0))
879 :
880 : /* Number of bytes in a directory block. */
881 7357420 : static inline unsigned int xfs_dir2_dirblock_bytes(struct xfs_sb *sbp)
882 : {
883 7357420 : return 1 << (sbp->sb_blocklog + sbp->sb_dirblklog);
884 : }
885 :
886 : xfs_failaddr_t xfs_da3_blkinfo_verify(struct xfs_buf *bp,
887 : struct xfs_da3_blkinfo *hdr3);
888 :
889 : /*
890 : * Parent pointer attribute format definition
891 : *
892 : * The xattr name encodes the parent inode number, generation and the crc32c
893 : * hash of the dirent name.
894 : *
895 : * The xattr value contains the dirent name.
896 : */
897 : struct xfs_parent_name_rec {
898 : __be64 p_ino;
899 : __be32 p_gen;
900 : __be32 p_namehash;
901 : };
902 :
903 : /*
904 : * Maximum size of the dirent name that can be stored in a parent pointer.
905 : * This matches the maximum dirent name length.
906 : */
907 : #define XFS_PARENT_DIRENT_NAME_MAX_SIZE \
908 : (MAXNAMELEN - 1)
909 :
910 : #endif /* __XFS_DA_FORMAT_H__ */
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