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 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 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 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 return (struct xfs_dir2_sf_entry *)
255 ((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 return (__be16 *)((char *)dup +
379 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 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 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 * Attribute storage when stored inside the inode.
593 *
594 * Small attribute lists are packed as tightly as possible so as to fit into the
595 * literal area of the inode.
596 *
597 * These "shortform" attribute forks consist of a single xfs_attr_sf_hdr header
598 * followed by zero or more xfs_attr_sf_entry structures.
599 */
600 struct xfs_attr_sf_hdr { /* constant-structure header block */
601 __be16 totsize; /* total bytes in shortform list */
602 __u8 count; /* count of active entries */
603 __u8 padding;
604 };
605
606 struct xfs_attr_sf_entry {
607 __u8 namelen; /* actual length of name (no NULL) */
608 __u8 valuelen; /* actual length of value (no NULL) */
609 __u8 flags; /* flags bits (XFS_ATTR_*) */
610 __u8 nameval[]; /* name & value bytes concatenated */
611 };
612
613 typedef struct xfs_attr_leaf_map { /* RLE map of free bytes */
614 __be16 base; /* base of free region */
615 __be16 size; /* length of free region */
616 } xfs_attr_leaf_map_t;
617
618 typedef struct xfs_attr_leaf_hdr { /* constant-structure header block */
619 xfs_da_blkinfo_t info; /* block type, links, etc. */
620 __be16 count; /* count of active leaf_entry's */
621 __be16 usedbytes; /* num bytes of names/values stored */
622 __be16 firstused; /* first used byte in name area */
623 __u8 holes; /* != 0 if blk needs compaction */
624 __u8 pad1;
625 xfs_attr_leaf_map_t freemap[XFS_ATTR_LEAF_MAPSIZE];
626 /* N largest free regions */
627 } xfs_attr_leaf_hdr_t;
628
629 typedef struct xfs_attr_leaf_entry { /* sorted on key, not name */
630 __be32 hashval; /* hash value of name */
631 __be16 nameidx; /* index into buffer of name/value */
632 __u8 flags; /* LOCAL/ROOT/SECURE/INCOMPLETE flag */
633 __u8 pad2; /* unused pad byte */
634 } xfs_attr_leaf_entry_t;
635
636 typedef struct xfs_attr_leaf_name_local {
637 __be16 valuelen; /* number of bytes in value */
638 __u8 namelen; /* length of name bytes */
639 /*
640 * In Linux 6.5 this flex array was converted from nameval[1] to
641 * nameval[]. Be very careful here about extra padding at the end;
642 * see xfs_attr_leaf_entsize_local() for details.
643 */
644 __u8 nameval[]; /* name/value bytes */
645 } xfs_attr_leaf_name_local_t;
646
647 typedef struct xfs_attr_leaf_name_remote {
648 __be32 valueblk; /* block number of value bytes */
649 __be32 valuelen; /* number of bytes in value */
650 __u8 namelen; /* length of name bytes */
651 /*
652 * In Linux 6.5 this flex array was converted from name[1] to name[].
653 * Be very careful here about extra padding at the end; see
654 * xfs_attr_leaf_entsize_remote() for details.
655 */
656 __u8 name[]; /* name bytes */
657 } xfs_attr_leaf_name_remote_t;
658
659 typedef struct xfs_attr_leafblock {
660 xfs_attr_leaf_hdr_t hdr; /* constant-structure header block */
661 xfs_attr_leaf_entry_t entries[]; /* sorted on key, not name */
662 /*
663 * The rest of the block contains the following structures after the
664 * leaf entries, growing from the bottom up. The variables are never
665 * referenced and definining them can actually make gcc optimize away
666 * accesses to the 'entries' array above index 0 so don't do that.
667 *
668 * xfs_attr_leaf_name_local_t namelist;
669 * xfs_attr_leaf_name_remote_t valuelist;
670 */
671 } xfs_attr_leafblock_t;
672
673 /*
674 * CRC enabled leaf structures. Called "version 3" structures to match the
675 * version number of the directory and dablk structures for this feature, and
676 * attr2 is already taken by the variable inode attribute fork size feature.
677 */
678 struct xfs_attr3_leaf_hdr {
679 struct xfs_da3_blkinfo info;
680 __be16 count;
681 __be16 usedbytes;
682 __be16 firstused;
683 __u8 holes;
684 __u8 pad1;
685 struct xfs_attr_leaf_map freemap[XFS_ATTR_LEAF_MAPSIZE];
686 __be32 pad2; /* 64 bit alignment */
687 };
688
689 #define XFS_ATTR3_LEAF_CRC_OFF (offsetof(struct xfs_attr3_leaf_hdr, info.crc))
690
691 struct xfs_attr3_leafblock {
692 struct xfs_attr3_leaf_hdr hdr;
693 struct xfs_attr_leaf_entry entries[];
694
695 /*
696 * The rest of the block contains the following structures after the
697 * leaf entries, growing from the bottom up. The variables are never
698 * referenced, the locations accessed purely from helper functions.
699 *
700 * struct xfs_attr_leaf_name_local
701 * struct xfs_attr_leaf_name_remote
702 */
703 };
704
705 /*
706 * Special value to represent fs block size in the leaf header firstused field.
707 * Only used when block size overflows the 2-bytes available on disk.
708 */
709 #define XFS_ATTR3_LEAF_NULLOFF 0
710
711 /*
712 * Flags used in the leaf_entry[i].flags field.
713 */
714 #define XFS_ATTR_LOCAL_BIT 0 /* attr is stored locally */
715 #define XFS_ATTR_ROOT_BIT 1 /* limit access to trusted attrs */
716 #define XFS_ATTR_SECURE_BIT 2 /* limit access to secure attrs */
717 #define XFS_ATTR_PARENT_BIT 3 /* parent pointer attrs */
718 #define XFS_ATTR_INCOMPLETE_BIT 7 /* attr in middle of create/delete */
719 #define XFS_ATTR_LOCAL (1u << XFS_ATTR_LOCAL_BIT)
720 #define XFS_ATTR_ROOT (1u << XFS_ATTR_ROOT_BIT)
721 #define XFS_ATTR_SECURE (1u << XFS_ATTR_SECURE_BIT)
722 #define XFS_ATTR_PARENT (1u << XFS_ATTR_PARENT_BIT)
723 #define XFS_ATTR_INCOMPLETE (1u << XFS_ATTR_INCOMPLETE_BIT)
724
725 #define XFS_ATTR_NSP_ONDISK_MASK (XFS_ATTR_ROOT | \
726 XFS_ATTR_SECURE | \
727 XFS_ATTR_PARENT)
728
729 /* Private attr namespaces not exposed to userspace */
730 #define XFS_ATTR_PRIVATE_NSP_MASK (XFS_ATTR_PARENT)
731
732 #define XFS_ATTR_ONDISK_MASK (XFS_ATTR_NSP_ONDISK_MASK | \
733 XFS_ATTR_LOCAL | \
734 XFS_ATTR_INCOMPLETE)
735
736 #define XFS_ATTR_NAMESPACE_STR \
737 { XFS_ATTR_LOCAL, "local" }, \
738 { XFS_ATTR_ROOT, "root" }, \
739 { XFS_ATTR_SECURE, "secure" }, \
740 { XFS_ATTR_PARENT, "parent" }
741
742 /*
743 * Alignment for namelist and valuelist entries (since they are mixed
744 * there can be only one alignment value)
745 */
746 #define XFS_ATTR_LEAF_NAME_ALIGN ((uint)sizeof(xfs_dablk_t))
747
748 static inline int
749 xfs_attr3_leaf_hdr_size(struct xfs_attr_leafblock *leafp)
750 {
751 if (leafp->hdr.info.magic == cpu_to_be16(XFS_ATTR3_LEAF_MAGIC))
752 return sizeof(struct xfs_attr3_leaf_hdr);
753 return sizeof(struct xfs_attr_leaf_hdr);
754 }
755
756 static inline struct xfs_attr_leaf_entry *
757 xfs_attr3_leaf_entryp(xfs_attr_leafblock_t *leafp)
758 {
759 if (leafp->hdr.info.magic == cpu_to_be16(XFS_ATTR3_LEAF_MAGIC))
760 return &((struct xfs_attr3_leafblock *)leafp)->entries[0];
761 return &leafp->entries[0];
762 }
763
764 /*
765 * Cast typed pointers for "local" and "remote" name/value structs.
766 */
767 static inline char *
768 xfs_attr3_leaf_name(xfs_attr_leafblock_t *leafp, int idx)
769 {
770 struct xfs_attr_leaf_entry *entries = xfs_attr3_leaf_entryp(leafp);
771
772 return &((char *)leafp)[be16_to_cpu(entries[idx].nameidx)];
773 }
774
775 static inline xfs_attr_leaf_name_remote_t *
776 xfs_attr3_leaf_name_remote(xfs_attr_leafblock_t *leafp, int idx)
777 {
778 return (xfs_attr_leaf_name_remote_t *)xfs_attr3_leaf_name(leafp, idx);
779 }
780
781 static inline xfs_attr_leaf_name_local_t *
782 xfs_attr3_leaf_name_local(xfs_attr_leafblock_t *leafp, int idx)
783 {
784 return (xfs_attr_leaf_name_local_t *)xfs_attr3_leaf_name(leafp, idx);
785 }
786
787 /*
788 * Calculate total bytes used (including trailing pad for alignment) for
789 * a "local" name/value structure, a "remote" name/value structure, and
790 * a pointer which might be either.
791 */
792 static inline int xfs_attr_leaf_entsize_remote(int nlen)
793 {
794 /*
795 * Prior to Linux 6.5, struct xfs_attr_leaf_name_remote ended with
796 * name[1], which was used as a flexarray. The layout of this struct
797 * is 9 bytes of fixed-length fields followed by a __u8 flex array at
798 * offset 9.
799 *
800 * On most architectures, struct xfs_attr_leaf_name_remote had two
801 * bytes of implicit padding at the end of the struct to make the
802 * struct length 12. After converting name[1] to name[], there are
803 * three implicit padding bytes and the struct size remains 12.
804 * However, there are compiler configurations that do not add implicit
805 * padding at all (m68k) and have been broken for years.
806 *
807 * This entsize computation historically added (the xattr name length)
808 * to (the padded struct length - 1) and rounded that sum up to the
809 * nearest multiple of 4 (NAME_ALIGN). IOWs, round_up(11 + nlen, 4).
810 * This is encoded in the ondisk format, so we cannot change this.
811 *
812 * Compute the entsize from offsetof of the flexarray and manually
813 * adding bytes for the implicit padding.
814 */
815 const size_t remotesize =
816 offsetof(struct xfs_attr_leaf_name_remote, name) + 2;
817
818 return round_up(remotesize + nlen, XFS_ATTR_LEAF_NAME_ALIGN);
819 }
820
821 static inline int xfs_attr_leaf_entsize_local(int nlen, int vlen)
822 {
823 /*
824 * Prior to Linux 6.5, struct xfs_attr_leaf_name_local ended with
825 * nameval[1], which was used as a flexarray. The layout of this
826 * struct is 3 bytes of fixed-length fields followed by a __u8 flex
827 * array at offset 3.
828 *
829 * struct xfs_attr_leaf_name_local had zero bytes of implicit padding
830 * at the end of the struct to make the struct length 4. On most
831 * architectures, after converting nameval[1] to nameval[], there is
832 * one implicit padding byte and the struct size remains 4. However,
833 * there are compiler configurations that do not add implicit padding
834 * at all (m68k) and would break.
835 *
836 * This entsize computation historically added (the xattr name and
837 * value length) to (the padded struct length - 1) and rounded that sum
838 * up to the nearest multiple of 4 (NAME_ALIGN). IOWs, the formula is
839 * round_up(3 + nlen + vlen, 4). This is encoded in the ondisk format,
840 * so we cannot change this.
841 *
842 * Compute the entsize from offsetof of the flexarray and manually
843 * adding bytes for the implicit padding.
844 */
845 const size_t localsize =
846 offsetof(struct xfs_attr_leaf_name_local, nameval);
847
848 return round_up(localsize + nlen + vlen, XFS_ATTR_LEAF_NAME_ALIGN);
849 }
850
851 static inline int xfs_attr_leaf_entsize_local_max(int bsize)
852 {
853 return (((bsize) >> 1) + ((bsize) >> 2));
854 }
855
856
857
858 /*
859 * Remote attribute block format definition
860 *
861 * There is one of these headers per filesystem block in a remote attribute.
862 * This is done to ensure there is a 1:1 mapping between the attribute value
863 * length and the number of blocks needed to store the attribute. This makes the
864 * verification of a buffer a little more complex, but greatly simplifies the
865 * allocation, reading and writing of these attributes as we don't have to guess
866 * the number of blocks needed to store the attribute data.
867 */
868 #define XFS_ATTR3_RMT_MAGIC 0x5841524d /* XARM */
869
870 struct xfs_attr3_rmt_hdr {
871 __be32 rm_magic;
872 __be32 rm_offset;
873 __be32 rm_bytes;
874 __be32 rm_crc;
875 uuid_t rm_uuid;
876 __be64 rm_owner;
877 __be64 rm_blkno;
878 __be64 rm_lsn;
879 };
880
881 #define XFS_ATTR3_RMT_CRC_OFF offsetof(struct xfs_attr3_rmt_hdr, rm_crc)
882
883 unsigned int xfs_attr3_rmt_buf_space(struct xfs_mount *mp);
884
885 /* Number of bytes in a directory block. */
886 static inline unsigned int xfs_dir2_dirblock_bytes(struct xfs_sb *sbp)
887 {
888 return 1 << (sbp->sb_blocklog + sbp->sb_dirblklog);
889 }
890
891 xfs_failaddr_t xfs_da3_blkinfo_verify(struct xfs_buf *bp,
892 struct xfs_da3_blkinfo *hdr3);
893
894 /*
895 * Parent pointer attribute format definition
896 *
897 * The xattr name contains the dirent name.
898 * The xattr value encodes the parent inode number and generation to ease
899 * opening parents by handle.
900 * The xattr hashval is xfs_dir2_namehash() ^ p_ino
901 */
902 struct xfs_parent_rec {
903 __be64 p_ino;
904 __be32 p_gen;
905 } __packed;
906
907 #endif /* __XFS_DA_FORMAT_H__ */
908
Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.