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 : /*
163 : * Byte offset in data block and shortform entry.
164 : */
165 : typedef uint16_t xfs_dir2_data_off_t;
166 : #define NULLDATAOFF 0xffffU
167 : typedef uint xfs_dir2_data_aoff_t; /* argument form */
168 :
169 : /*
170 : * Offset in data space of a data entry.
171 : */
172 : typedef uint32_t xfs_dir2_dataptr_t;
173 : #define XFS_DIR2_MAX_DATAPTR ((xfs_dir2_dataptr_t)0xffffffff)
174 : #define XFS_DIR2_NULL_DATAPTR ((xfs_dir2_dataptr_t)0)
175 :
176 : /*
177 : * Byte offset in a directory.
178 : */
179 : typedef xfs_off_t xfs_dir2_off_t;
180 :
181 : /*
182 : * Directory block number (logical dirblk in file)
183 : */
184 : typedef uint32_t xfs_dir2_db_t;
185 :
186 : #define XFS_INO32_SIZE 4
187 : #define XFS_INO64_SIZE 8
188 : #define XFS_INO64_DIFF (XFS_INO64_SIZE - XFS_INO32_SIZE)
189 :
190 : #define XFS_DIR2_MAX_SHORT_INUM ((xfs_ino_t)0xffffffffULL)
191 :
192 : /*
193 : * Directory layout when stored internal to an inode.
194 : *
195 : * Small directories are packed as tightly as possible so as to fit into the
196 : * literal area of the inode. These "shortform" directories consist of a
197 : * single xfs_dir2_sf_hdr header followed by zero or more xfs_dir2_sf_entry
198 : * structures. Due the different inode number storage size and the variable
199 : * length name field in the xfs_dir2_sf_entry all these structure are
200 : * variable length, and the accessors in this file should be used to iterate
201 : * over them.
202 : */
203 : typedef struct xfs_dir2_sf_hdr {
204 : uint8_t count; /* count of entries */
205 : uint8_t i8count; /* count of 8-byte inode #s */
206 : uint8_t parent[8]; /* parent dir inode number */
207 : } __packed xfs_dir2_sf_hdr_t;
208 :
209 : typedef struct xfs_dir2_sf_entry {
210 : __u8 namelen; /* actual name length */
211 : __u8 offset[2]; /* saved offset */
212 : __u8 name[]; /* name, variable size */
213 : /*
214 : * A single byte containing the file type field follows the inode
215 : * number for version 3 directory entries.
216 : *
217 : * A 64-bit or 32-bit inode number follows here, at a variable offset
218 : * after the name.
219 : */
220 : } __packed xfs_dir2_sf_entry_t;
221 :
222 : static inline int xfs_dir2_sf_hdr_size(int i8count)
223 : {
224 1061046133 : return sizeof(struct xfs_dir2_sf_hdr) -
225 : (i8count == 0) * XFS_INO64_DIFF;
226 : }
227 :
228 : static inline xfs_dir2_data_aoff_t
229 : xfs_dir2_sf_get_offset(xfs_dir2_sf_entry_t *sfep)
230 : {
231 5502126779 : return get_unaligned_be16(sfep->offset);
232 : }
233 :
234 : static inline void
235 : xfs_dir2_sf_put_offset(xfs_dir2_sf_entry_t *sfep, xfs_dir2_data_aoff_t off)
236 : {
237 29824046 : put_unaligned_be16(off, sfep->offset);
238 : }
239 :
240 : static inline struct xfs_dir2_sf_entry *
241 : xfs_dir2_sf_firstentry(struct xfs_dir2_sf_hdr *hdr)
242 : {
243 3004182522 : return (struct xfs_dir2_sf_entry *)
244 1502091261 : ((char *)hdr + xfs_dir2_sf_hdr_size(hdr->i8count));
245 : }
246 :
247 : /*
248 : * Data block structures.
249 : *
250 : * A pure data block looks like the following drawing on disk:
251 : *
252 : * +-------------------------------------------------+
253 : * | xfs_dir2_data_hdr_t |
254 : * +-------------------------------------------------+
255 : * | xfs_dir2_data_entry_t OR xfs_dir2_data_unused_t |
256 : * | xfs_dir2_data_entry_t OR xfs_dir2_data_unused_t |
257 : * | xfs_dir2_data_entry_t OR xfs_dir2_data_unused_t |
258 : * | ... |
259 : * +-------------------------------------------------+
260 : * | unused space |
261 : * +-------------------------------------------------+
262 : *
263 : * As all the entries are variable size structures the accessors below should
264 : * be used to iterate over them.
265 : *
266 : * In addition to the pure data blocks for the data and node formats,
267 : * most structures are also used for the combined data/freespace "block"
268 : * format below.
269 : */
270 :
271 : #define XFS_DIR2_DATA_ALIGN_LOG 3 /* i.e., 8 bytes */
272 : #define XFS_DIR2_DATA_ALIGN (1 << XFS_DIR2_DATA_ALIGN_LOG)
273 : #define XFS_DIR2_DATA_FREE_TAG 0xffff
274 : #define XFS_DIR2_DATA_FD_COUNT 3
275 :
276 : /*
277 : * Directory address space divided into sections,
278 : * spaces separated by 32GB.
279 : */
280 : #define XFS_DIR2_MAX_SPACES 3
281 : #define XFS_DIR2_SPACE_SIZE (1ULL << (32 + XFS_DIR2_DATA_ALIGN_LOG))
282 : #define XFS_DIR2_DATA_SPACE 0
283 : #define XFS_DIR2_DATA_OFFSET (XFS_DIR2_DATA_SPACE * XFS_DIR2_SPACE_SIZE)
284 :
285 : /*
286 : * Describe a free area in the data block.
287 : *
288 : * The freespace will be formatted as a xfs_dir2_data_unused_t.
289 : */
290 : typedef struct xfs_dir2_data_free {
291 : __be16 offset; /* start of freespace */
292 : __be16 length; /* length of freespace */
293 : } xfs_dir2_data_free_t;
294 :
295 : /*
296 : * Header for the data blocks.
297 : *
298 : * The code knows that XFS_DIR2_DATA_FD_COUNT is 3.
299 : */
300 : typedef struct xfs_dir2_data_hdr {
301 : __be32 magic; /* XFS_DIR2_DATA_MAGIC or */
302 : /* XFS_DIR2_BLOCK_MAGIC */
303 : xfs_dir2_data_free_t bestfree[XFS_DIR2_DATA_FD_COUNT];
304 : } xfs_dir2_data_hdr_t;
305 :
306 : /*
307 : * define a structure for all the verification fields we are adding to the
308 : * directory block structures. This will be used in several structures.
309 : * The magic number must be the first entry to align with all the dir2
310 : * structures so we determine how to decode them just by the magic number.
311 : */
312 : struct xfs_dir3_blk_hdr {
313 : __be32 magic; /* magic number */
314 : __be32 crc; /* CRC of block */
315 : __be64 blkno; /* first block of the buffer */
316 : __be64 lsn; /* sequence number of last write */
317 : uuid_t uuid; /* filesystem we belong to */
318 : __be64 owner; /* inode that owns the block */
319 : };
320 :
321 : struct xfs_dir3_data_hdr {
322 : struct xfs_dir3_blk_hdr hdr;
323 : xfs_dir2_data_free_t best_free[XFS_DIR2_DATA_FD_COUNT];
324 : __be32 pad; /* 64 bit alignment */
325 : };
326 :
327 : #define XFS_DIR3_DATA_CRC_OFF offsetof(struct xfs_dir3_data_hdr, hdr.crc)
328 :
329 : /*
330 : * Active entry in a data block.
331 : *
332 : * Aligned to 8 bytes. After the variable length name field there is a
333 : * 2 byte tag field, which can be accessed using xfs_dir3_data_entry_tag_p.
334 : *
335 : * For dir3 structures, there is file type field between the name and the tag.
336 : * This can only be manipulated by helper functions. It is packed hard against
337 : * the end of the name so any padding for rounding is between the file type and
338 : * the tag.
339 : */
340 : typedef struct xfs_dir2_data_entry {
341 : __be64 inumber; /* inode number */
342 : __u8 namelen; /* name length */
343 : __u8 name[]; /* name bytes, no null */
344 : /* __u8 filetype; */ /* type of inode we point to */
345 : /* __be16 tag; */ /* starting offset of us */
346 : } xfs_dir2_data_entry_t;
347 :
348 : /*
349 : * Unused entry in a data block.
350 : *
351 : * Aligned to 8 bytes. Tag appears as the last 2 bytes and must be accessed
352 : * using xfs_dir2_data_unused_tag_p.
353 : */
354 : typedef struct xfs_dir2_data_unused {
355 : __be16 freetag; /* XFS_DIR2_DATA_FREE_TAG */
356 : __be16 length; /* total free length */
357 : /* variable offset */
358 : __be16 tag; /* starting offset of us */
359 : } xfs_dir2_data_unused_t;
360 :
361 : /*
362 : * Pointer to a freespace's tag word.
363 : */
364 : static inline __be16 *
365 6120475842 : xfs_dir2_data_unused_tag_p(struct xfs_dir2_data_unused *dup)
366 : {
367 12240951684 : return (__be16 *)((char *)dup +
368 6120475842 : be16_to_cpu(dup->length) - sizeof(__be16));
369 : }
370 :
371 : /*
372 : * Leaf block structures.
373 : *
374 : * A pure leaf block looks like the following drawing on disk:
375 : *
376 : * +---------------------------+
377 : * | xfs_dir2_leaf_hdr_t |
378 : * +---------------------------+
379 : * | xfs_dir2_leaf_entry_t |
380 : * | xfs_dir2_leaf_entry_t |
381 : * | xfs_dir2_leaf_entry_t |
382 : * | xfs_dir2_leaf_entry_t |
383 : * | ... |
384 : * +---------------------------+
385 : * | xfs_dir2_data_off_t |
386 : * | xfs_dir2_data_off_t |
387 : * | xfs_dir2_data_off_t |
388 : * | ... |
389 : * +---------------------------+
390 : * | xfs_dir2_leaf_tail_t |
391 : * +---------------------------+
392 : *
393 : * The xfs_dir2_data_off_t members (bests) and tail are at the end of the block
394 : * for single-leaf (magic = XFS_DIR2_LEAF1_MAGIC) blocks only, but not present
395 : * for directories with separate leaf nodes and free space blocks
396 : * (magic = XFS_DIR2_LEAFN_MAGIC).
397 : *
398 : * As all the entries are variable size structures the accessors below should
399 : * be used to iterate over them.
400 : */
401 :
402 : /*
403 : * Offset of the leaf/node space. First block in this space
404 : * is the btree root.
405 : */
406 : #define XFS_DIR2_LEAF_SPACE 1
407 : #define XFS_DIR2_LEAF_OFFSET (XFS_DIR2_LEAF_SPACE * XFS_DIR2_SPACE_SIZE)
408 :
409 : /*
410 : * Leaf block header.
411 : */
412 : typedef struct xfs_dir2_leaf_hdr {
413 : xfs_da_blkinfo_t info; /* header for da routines */
414 : __be16 count; /* count of entries */
415 : __be16 stale; /* count of stale entries */
416 : } xfs_dir2_leaf_hdr_t;
417 :
418 : struct xfs_dir3_leaf_hdr {
419 : struct xfs_da3_blkinfo info; /* header for da routines */
420 : __be16 count; /* count of entries */
421 : __be16 stale; /* count of stale entries */
422 : __be32 pad; /* 64 bit alignment */
423 : };
424 :
425 : /*
426 : * Leaf block entry.
427 : */
428 : typedef struct xfs_dir2_leaf_entry {
429 : __be32 hashval; /* hash value of name */
430 : __be32 address; /* address of data entry */
431 : } xfs_dir2_leaf_entry_t;
432 :
433 : /*
434 : * Leaf block tail.
435 : */
436 : typedef struct xfs_dir2_leaf_tail {
437 : __be32 bestcount;
438 : } xfs_dir2_leaf_tail_t;
439 :
440 : /*
441 : * Leaf block.
442 : */
443 : typedef struct xfs_dir2_leaf {
444 : xfs_dir2_leaf_hdr_t hdr; /* leaf header */
445 : xfs_dir2_leaf_entry_t __ents[]; /* entries */
446 : } xfs_dir2_leaf_t;
447 :
448 : struct xfs_dir3_leaf {
449 : struct xfs_dir3_leaf_hdr hdr; /* leaf header */
450 : struct xfs_dir2_leaf_entry __ents[]; /* entries */
451 : };
452 :
453 : #define XFS_DIR3_LEAF_CRC_OFF offsetof(struct xfs_dir3_leaf_hdr, info.crc)
454 :
455 : /*
456 : * Get address of the bests array in the single-leaf block.
457 : */
458 : static inline __be16 *
459 50857449 : xfs_dir2_leaf_bests_p(struct xfs_dir2_leaf_tail *ltp)
460 : {
461 50857449 : return (__be16 *)ltp - be32_to_cpu(ltp->bestcount);
462 : }
463 :
464 : /*
465 : * Free space block definitions for the node format.
466 : */
467 :
468 : /*
469 : * Offset of the freespace index.
470 : */
471 : #define XFS_DIR2_FREE_SPACE 2
472 : #define XFS_DIR2_FREE_OFFSET (XFS_DIR2_FREE_SPACE * XFS_DIR2_SPACE_SIZE)
473 :
474 : typedef struct xfs_dir2_free_hdr {
475 : __be32 magic; /* XFS_DIR2_FREE_MAGIC */
476 : __be32 firstdb; /* db of first entry */
477 : __be32 nvalid; /* count of valid entries */
478 : __be32 nused; /* count of used entries */
479 : } xfs_dir2_free_hdr_t;
480 :
481 : typedef struct xfs_dir2_free {
482 : xfs_dir2_free_hdr_t hdr; /* block header */
483 : __be16 bests[]; /* best free counts */
484 : /* unused entries are -1 */
485 : } xfs_dir2_free_t;
486 :
487 : struct xfs_dir3_free_hdr {
488 : struct xfs_dir3_blk_hdr hdr;
489 : __be32 firstdb; /* db of first entry */
490 : __be32 nvalid; /* count of valid entries */
491 : __be32 nused; /* count of used entries */
492 : __be32 pad; /* 64 bit alignment */
493 : };
494 :
495 : struct xfs_dir3_free {
496 : struct xfs_dir3_free_hdr hdr;
497 : __be16 bests[]; /* best free counts */
498 : /* unused entries are -1 */
499 : };
500 :
501 : #define XFS_DIR3_FREE_CRC_OFF offsetof(struct xfs_dir3_free, hdr.hdr.crc)
502 :
503 : /*
504 : * Single block format.
505 : *
506 : * The single block format looks like the following drawing on disk:
507 : *
508 : * +-------------------------------------------------+
509 : * | xfs_dir2_data_hdr_t |
510 : * +-------------------------------------------------+
511 : * | xfs_dir2_data_entry_t OR xfs_dir2_data_unused_t |
512 : * | xfs_dir2_data_entry_t OR xfs_dir2_data_unused_t |
513 : * | xfs_dir2_data_entry_t OR xfs_dir2_data_unused_t :
514 : * | ... |
515 : * +-------------------------------------------------+
516 : * | unused space |
517 : * +-------------------------------------------------+
518 : * | ... |
519 : * | xfs_dir2_leaf_entry_t |
520 : * | xfs_dir2_leaf_entry_t |
521 : * +-------------------------------------------------+
522 : * | xfs_dir2_block_tail_t |
523 : * +-------------------------------------------------+
524 : *
525 : * As all the entries are variable size structures the accessors below should
526 : * be used to iterate over them.
527 : */
528 :
529 : typedef struct xfs_dir2_block_tail {
530 : __be32 count; /* count of leaf entries */
531 : __be32 stale; /* count of stale lf entries */
532 : } xfs_dir2_block_tail_t;
533 :
534 : /*
535 : * Pointer to the leaf entries embedded in a data block (1-block format)
536 : */
537 : static inline struct xfs_dir2_leaf_entry *
538 54433356 : xfs_dir2_block_leaf_p(struct xfs_dir2_block_tail *btp)
539 : {
540 54433356 : return ((struct xfs_dir2_leaf_entry *)btp) - be32_to_cpu(btp->count);
541 : }
542 :
543 :
544 : /*
545 : * Attribute storage layout
546 : *
547 : * Attribute lists are structured around Btrees where all the data
548 : * elements are in the leaf nodes. Attribute names are hashed into an int,
549 : * then that int is used as the index into the Btree. Since the hashval
550 : * of an attribute name may not be unique, we may have duplicate keys. The
551 : * internal links in the Btree are logical block offsets into the file.
552 : *
553 : * Struct leaf_entry's are packed from the top. Name/values grow from the
554 : * bottom but are not packed. The freemap contains run-length-encoded entries
555 : * for the free bytes after the leaf_entry's, but only the N largest such,
556 : * smaller runs are dropped. When the freemap doesn't show enough space
557 : * for an allocation, we compact the name/value area and try again. If we
558 : * still don't have enough space, then we have to split the block. The
559 : * name/value structs (both local and remote versions) must be 32bit aligned.
560 : *
561 : * Since we have duplicate hash keys, for each key that matches, compare
562 : * the actual name string. The root and intermediate node search always
563 : * takes the first-in-the-block key match found, so we should only have
564 : * to work "forw"ard. If none matches, continue with the "forw"ard leaf
565 : * nodes until the hash key changes or the attribute name is found.
566 : *
567 : * We store the fact that an attribute is a ROOT/USER/SECURE attribute in
568 : * the leaf_entry. The namespaces are independent only because we also look
569 : * at the namespace bit when we are looking for a matching attribute name.
570 : *
571 : * We also store an "incomplete" bit in the leaf_entry. It shows that an
572 : * attribute is in the middle of being created and should not be shown to
573 : * the user if we crash during the time that the bit is set. We clear the
574 : * bit when we have finished setting up the attribute. We do this because
575 : * we cannot create some large attributes inside a single transaction, and we
576 : * need some indication that we weren't finished if we crash in the middle.
577 : */
578 : #define XFS_ATTR_LEAF_MAPSIZE 3 /* how many freespace slots */
579 :
580 : /*
581 : * Entries are packed toward the top as tight as possible.
582 : */
583 : struct xfs_attr_shortform {
584 : struct xfs_attr_sf_hdr { /* constant-structure header block */
585 : __be16 totsize; /* total bytes in shortform list */
586 : __u8 count; /* count of active entries */
587 : __u8 padding;
588 : } hdr;
589 : struct xfs_attr_sf_entry {
590 : uint8_t namelen; /* actual length of name (no NULL) */
591 : uint8_t valuelen; /* actual length of value (no NULL) */
592 : uint8_t flags; /* flags bits (see xfs_attr_leaf.h) */
593 : uint8_t nameval[]; /* name & value bytes concatenated */
594 : } list[]; /* variable sized array */
595 : };
596 :
597 : typedef struct xfs_attr_leaf_map { /* RLE map of free bytes */
598 : __be16 base; /* base of free region */
599 : __be16 size; /* length of free region */
600 : } xfs_attr_leaf_map_t;
601 :
602 : typedef struct xfs_attr_leaf_hdr { /* constant-structure header block */
603 : xfs_da_blkinfo_t info; /* block type, links, etc. */
604 : __be16 count; /* count of active leaf_entry's */
605 : __be16 usedbytes; /* num bytes of names/values stored */
606 : __be16 firstused; /* first used byte in name area */
607 : __u8 holes; /* != 0 if blk needs compaction */
608 : __u8 pad1;
609 : xfs_attr_leaf_map_t freemap[XFS_ATTR_LEAF_MAPSIZE];
610 : /* N largest free regions */
611 : } xfs_attr_leaf_hdr_t;
612 :
613 : typedef struct xfs_attr_leaf_entry { /* sorted on key, not name */
614 : __be32 hashval; /* hash value of name */
615 : __be16 nameidx; /* index into buffer of name/value */
616 : __u8 flags; /* LOCAL/ROOT/SECURE/INCOMPLETE flag */
617 : __u8 pad2; /* unused pad byte */
618 : } xfs_attr_leaf_entry_t;
619 :
620 : typedef struct xfs_attr_leaf_name_local {
621 : __be16 valuelen; /* number of bytes in value */
622 : __u8 namelen; /* length of name bytes */
623 : /*
624 : * In Linux 6.5 this flex array was converted from nameval[1] to
625 : * nameval[]. Be very careful here about extra padding at the end;
626 : * see xfs_attr_leaf_entsize_local() for details.
627 : */
628 : __u8 nameval[]; /* name/value bytes */
629 : } xfs_attr_leaf_name_local_t;
630 :
631 : typedef struct xfs_attr_leaf_name_remote {
632 : __be32 valueblk; /* block number of value bytes */
633 : __be32 valuelen; /* number of bytes in value */
634 : __u8 namelen; /* length of name bytes */
635 : /*
636 : * In Linux 6.5 this flex array was converted from name[1] to name[].
637 : * Be very careful here about extra padding at the end; see
638 : * xfs_attr_leaf_entsize_remote() for details.
639 : */
640 : __u8 name[]; /* name bytes */
641 : } xfs_attr_leaf_name_remote_t;
642 :
643 : typedef struct xfs_attr_leafblock {
644 : xfs_attr_leaf_hdr_t hdr; /* constant-structure header block */
645 : xfs_attr_leaf_entry_t entries[]; /* sorted on key, not name */
646 : /*
647 : * The rest of the block contains the following structures after the
648 : * leaf entries, growing from the bottom up. The variables are never
649 : * referenced and definining them can actually make gcc optimize away
650 : * accesses to the 'entries' array above index 0 so don't do that.
651 : *
652 : * xfs_attr_leaf_name_local_t namelist;
653 : * xfs_attr_leaf_name_remote_t valuelist;
654 : */
655 : } xfs_attr_leafblock_t;
656 :
657 : /*
658 : * CRC enabled leaf structures. Called "version 3" structures to match the
659 : * version number of the directory and dablk structures for this feature, and
660 : * attr2 is already taken by the variable inode attribute fork size feature.
661 : */
662 : struct xfs_attr3_leaf_hdr {
663 : struct xfs_da3_blkinfo info;
664 : __be16 count;
665 : __be16 usedbytes;
666 : __be16 firstused;
667 : __u8 holes;
668 : __u8 pad1;
669 : struct xfs_attr_leaf_map freemap[XFS_ATTR_LEAF_MAPSIZE];
670 : __be32 pad2; /* 64 bit alignment */
671 : };
672 :
673 : #define XFS_ATTR3_LEAF_CRC_OFF (offsetof(struct xfs_attr3_leaf_hdr, info.crc))
674 :
675 : struct xfs_attr3_leafblock {
676 : struct xfs_attr3_leaf_hdr hdr;
677 : struct xfs_attr_leaf_entry entries[];
678 :
679 : /*
680 : * The rest of the block contains the following structures after the
681 : * leaf entries, growing from the bottom up. The variables are never
682 : * referenced, the locations accessed purely from helper functions.
683 : *
684 : * struct xfs_attr_leaf_name_local
685 : * struct xfs_attr_leaf_name_remote
686 : */
687 : };
688 :
689 : /*
690 : * Special value to represent fs block size in the leaf header firstused field.
691 : * Only used when block size overflows the 2-bytes available on disk.
692 : */
693 : #define XFS_ATTR3_LEAF_NULLOFF 0
694 :
695 : /*
696 : * Flags used in the leaf_entry[i].flags field.
697 : */
698 : #define XFS_ATTR_LOCAL_BIT 0 /* attr is stored locally */
699 : #define XFS_ATTR_ROOT_BIT 1 /* limit access to trusted attrs */
700 : #define XFS_ATTR_SECURE_BIT 2 /* limit access to secure attrs */
701 : #define XFS_ATTR_INCOMPLETE_BIT 7 /* attr in middle of create/delete */
702 : #define XFS_ATTR_LOCAL (1u << XFS_ATTR_LOCAL_BIT)
703 : #define XFS_ATTR_ROOT (1u << XFS_ATTR_ROOT_BIT)
704 : #define XFS_ATTR_SECURE (1u << XFS_ATTR_SECURE_BIT)
705 : #define XFS_ATTR_INCOMPLETE (1u << XFS_ATTR_INCOMPLETE_BIT)
706 : #define XFS_ATTR_NSP_ONDISK_MASK (XFS_ATTR_ROOT | XFS_ATTR_SECURE)
707 :
708 : /*
709 : * Alignment for namelist and valuelist entries (since they are mixed
710 : * there can be only one alignment value)
711 : */
712 : #define XFS_ATTR_LEAF_NAME_ALIGN ((uint)sizeof(xfs_dablk_t))
713 :
714 : static inline int
715 : xfs_attr3_leaf_hdr_size(struct xfs_attr_leafblock *leafp)
716 : {
717 361153273 : if (leafp->hdr.info.magic == cpu_to_be16(XFS_ATTR3_LEAF_MAGIC))
718 361170070 : return sizeof(struct xfs_attr3_leaf_hdr);
719 : return sizeof(struct xfs_attr_leaf_hdr);
720 : }
721 :
722 : static inline struct xfs_attr_leaf_entry *
723 : xfs_attr3_leaf_entryp(xfs_attr_leafblock_t *leafp)
724 : {
725 1124520956 : if (leafp->hdr.info.magic == cpu_to_be16(XFS_ATTR3_LEAF_MAGIC))
726 7308214739 : return &((struct xfs_attr3_leafblock *)leafp)->entries[0];
727 0 : return &leafp->entries[0];
728 : }
729 :
730 : /*
731 : * Cast typed pointers for "local" and "remote" name/value structs.
732 : */
733 : static inline char *
734 6181927242 : xfs_attr3_leaf_name(xfs_attr_leafblock_t *leafp, int idx)
735 : {
736 6181927242 : struct xfs_attr_leaf_entry *entries = xfs_attr3_leaf_entryp(leafp);
737 :
738 6181927242 : return &((char *)leafp)[be16_to_cpu(entries[idx].nameidx)];
739 : }
740 :
741 : static inline xfs_attr_leaf_name_remote_t *
742 : xfs_attr3_leaf_name_remote(xfs_attr_leafblock_t *leafp, int idx)
743 : {
744 4224 : return (xfs_attr_leaf_name_remote_t *)xfs_attr3_leaf_name(leafp, idx);
745 : }
746 :
747 : static inline xfs_attr_leaf_name_local_t *
748 : xfs_attr3_leaf_name_local(xfs_attr_leafblock_t *leafp, int idx)
749 : {
750 6045922307 : return (xfs_attr_leaf_name_local_t *)xfs_attr3_leaf_name(leafp, idx);
751 : }
752 :
753 : /*
754 : * Calculate total bytes used (including trailing pad for alignment) for
755 : * a "local" name/value structure, a "remote" name/value structure, and
756 : * a pointer which might be either.
757 : */
758 : static inline int xfs_attr_leaf_entsize_remote(int nlen)
759 : {
760 : /*
761 : * Prior to Linux 6.5, struct xfs_attr_leaf_name_remote ended with
762 : * name[1], which was used as a flexarray. The layout of this struct
763 : * is 9 bytes of fixed-length fields followed by a __u8 flex array at
764 : * offset 9.
765 : *
766 : * On most architectures, struct xfs_attr_leaf_name_remote had two
767 : * bytes of implicit padding at the end of the struct to make the
768 : * struct length 12. After converting name[1] to name[], there are
769 : * three implicit padding bytes and the struct size remains 12.
770 : * However, there are compiler configurations that do not add implicit
771 : * padding at all (m68k) and have been broken for years.
772 : *
773 : * This entsize computation historically added (the xattr name length)
774 : * to (the padded struct length - 1) and rounded that sum up to the
775 : * nearest multiple of 4 (NAME_ALIGN). IOWs, round_up(11 + nlen, 4).
776 : * This is encoded in the ondisk format, so we cannot change this.
777 : *
778 : * Compute the entsize from offsetof of the flexarray and manually
779 : * adding bytes for the implicit padding.
780 : */
781 3774 : const size_t remotesize =
782 : offsetof(struct xfs_attr_leaf_name_remote, name) + 2;
783 :
784 3774 : return round_up(remotesize + nlen, XFS_ATTR_LEAF_NAME_ALIGN);
785 : }
786 :
787 : static inline int xfs_attr_leaf_entsize_local(int nlen, int vlen)
788 : {
789 : /*
790 : * Prior to Linux 6.5, struct xfs_attr_leaf_name_local ended with
791 : * nameval[1], which was used as a flexarray. The layout of this
792 : * struct is 3 bytes of fixed-length fields followed by a __u8 flex
793 : * array at offset 3.
794 : *
795 : * struct xfs_attr_leaf_name_local had zero bytes of implicit padding
796 : * at the end of the struct to make the struct length 4. On most
797 : * architectures, after converting nameval[1] to nameval[], there is
798 : * one implicit padding byte and the struct size remains 4. However,
799 : * there are compiler configurations that do not add implicit padding
800 : * at all (m68k) and would break.
801 : *
802 : * This entsize computation historically added (the xattr name and
803 : * value length) to (the padded struct length - 1) and rounded that sum
804 : * up to the nearest multiple of 4 (NAME_ALIGN). IOWs, the formula is
805 : * round_up(3 + nlen + vlen, 4). This is encoded in the ondisk format,
806 : * so we cannot change this.
807 : *
808 : * Compute the entsize from offsetof of the flexarray and manually
809 : * adding bytes for the implicit padding.
810 : */
811 630402260 : const size_t localsize =
812 : offsetof(struct xfs_attr_leaf_name_local, nameval);
813 :
814 630402260 : return round_up(localsize + nlen + vlen, XFS_ATTR_LEAF_NAME_ALIGN);
815 : }
816 :
817 : static inline int xfs_attr_leaf_entsize_local_max(int bsize)
818 : {
819 232313413 : return (((bsize) >> 1) + ((bsize) >> 2));
820 : }
821 :
822 :
823 :
824 : /*
825 : * Remote attribute block format definition
826 : *
827 : * There is one of these headers per filesystem block in a remote attribute.
828 : * This is done to ensure there is a 1:1 mapping between the attribute value
829 : * length and the number of blocks needed to store the attribute. This makes the
830 : * verification of a buffer a little more complex, but greatly simplifies the
831 : * allocation, reading and writing of these attributes as we don't have to guess
832 : * the number of blocks needed to store the attribute data.
833 : */
834 : #define XFS_ATTR3_RMT_MAGIC 0x5841524d /* XARM */
835 :
836 : struct xfs_attr3_rmt_hdr {
837 : __be32 rm_magic;
838 : __be32 rm_offset;
839 : __be32 rm_bytes;
840 : __be32 rm_crc;
841 : uuid_t rm_uuid;
842 : __be64 rm_owner;
843 : __be64 rm_blkno;
844 : __be64 rm_lsn;
845 : };
846 :
847 : #define XFS_ATTR3_RMT_CRC_OFF offsetof(struct xfs_attr3_rmt_hdr, rm_crc)
848 :
849 : #define XFS_ATTR3_RMT_BUF_SPACE(mp, bufsize) \
850 : ((bufsize) - (xfs_has_crc((mp)) ? \
851 : sizeof(struct xfs_attr3_rmt_hdr) : 0))
852 :
853 : /* Number of bytes in a directory block. */
854 1947374 : static inline unsigned int xfs_dir2_dirblock_bytes(struct xfs_sb *sbp)
855 : {
856 1947374 : return 1 << (sbp->sb_blocklog + sbp->sb_dirblklog);
857 : }
858 :
859 : xfs_failaddr_t xfs_da3_blkinfo_verify(struct xfs_buf *bp,
860 : struct xfs_da3_blkinfo *hdr3);
861 :
862 : #endif /* __XFS_DA_FORMAT_H__ */
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