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(i8count: 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_INCOMPLETE_BIT 7 /* attr in middle of create/delete */ |
718 | #define XFS_ATTR_LOCAL (1u << XFS_ATTR_LOCAL_BIT) |
719 | #define XFS_ATTR_ROOT (1u << XFS_ATTR_ROOT_BIT) |
720 | #define XFS_ATTR_SECURE (1u << XFS_ATTR_SECURE_BIT) |
721 | #define XFS_ATTR_INCOMPLETE (1u << XFS_ATTR_INCOMPLETE_BIT) |
722 | #define XFS_ATTR_NSP_ONDISK_MASK (XFS_ATTR_ROOT | XFS_ATTR_SECURE) |
723 | |
724 | /* |
725 | * Alignment for namelist and valuelist entries (since they are mixed |
726 | * there can be only one alignment value) |
727 | */ |
728 | #define XFS_ATTR_LEAF_NAME_ALIGN ((uint)sizeof(xfs_dablk_t)) |
729 | |
730 | static inline int |
731 | xfs_attr3_leaf_hdr_size(struct xfs_attr_leafblock *leafp) |
732 | { |
733 | if (leafp->hdr.info.magic == cpu_to_be16(XFS_ATTR3_LEAF_MAGIC)) |
734 | return sizeof(struct xfs_attr3_leaf_hdr); |
735 | return sizeof(struct xfs_attr_leaf_hdr); |
736 | } |
737 | |
738 | static inline struct xfs_attr_leaf_entry * |
739 | xfs_attr3_leaf_entryp(xfs_attr_leafblock_t *leafp) |
740 | { |
741 | if (leafp->hdr.info.magic == cpu_to_be16(XFS_ATTR3_LEAF_MAGIC)) |
742 | return &((struct xfs_attr3_leafblock *)leafp)->entries[0]; |
743 | return &leafp->entries[0]; |
744 | } |
745 | |
746 | /* |
747 | * Cast typed pointers for "local" and "remote" name/value structs. |
748 | */ |
749 | static inline char * |
750 | xfs_attr3_leaf_name(xfs_attr_leafblock_t *leafp, int idx) |
751 | { |
752 | struct xfs_attr_leaf_entry *entries = xfs_attr3_leaf_entryp(leafp); |
753 | |
754 | return &((char *)leafp)[be16_to_cpu(entries[idx].nameidx)]; |
755 | } |
756 | |
757 | static inline xfs_attr_leaf_name_remote_t * |
758 | xfs_attr3_leaf_name_remote(xfs_attr_leafblock_t *leafp, int idx) |
759 | { |
760 | return (xfs_attr_leaf_name_remote_t *)xfs_attr3_leaf_name(leafp, idx); |
761 | } |
762 | |
763 | static inline xfs_attr_leaf_name_local_t * |
764 | xfs_attr3_leaf_name_local(xfs_attr_leafblock_t *leafp, int idx) |
765 | { |
766 | return (xfs_attr_leaf_name_local_t *)xfs_attr3_leaf_name(leafp, idx); |
767 | } |
768 | |
769 | /* |
770 | * Calculate total bytes used (including trailing pad for alignment) for |
771 | * a "local" name/value structure, a "remote" name/value structure, and |
772 | * a pointer which might be either. |
773 | */ |
774 | static inline int xfs_attr_leaf_entsize_remote(int nlen) |
775 | { |
776 | /* |
777 | * Prior to Linux 6.5, struct xfs_attr_leaf_name_remote ended with |
778 | * name[1], which was used as a flexarray. The layout of this struct |
779 | * is 9 bytes of fixed-length fields followed by a __u8 flex array at |
780 | * offset 9. |
781 | * |
782 | * On most architectures, struct xfs_attr_leaf_name_remote had two |
783 | * bytes of implicit padding at the end of the struct to make the |
784 | * struct length 12. After converting name[1] to name[], there are |
785 | * three implicit padding bytes and the struct size remains 12. |
786 | * However, there are compiler configurations that do not add implicit |
787 | * padding at all (m68k) and have been broken for years. |
788 | * |
789 | * This entsize computation historically added (the xattr name length) |
790 | * to (the padded struct length - 1) and rounded that sum up to the |
791 | * nearest multiple of 4 (NAME_ALIGN). IOWs, round_up(11 + nlen, 4). |
792 | * This is encoded in the ondisk format, so we cannot change this. |
793 | * |
794 | * Compute the entsize from offsetof of the flexarray and manually |
795 | * adding bytes for the implicit padding. |
796 | */ |
797 | const size_t remotesize = |
798 | offsetof(struct xfs_attr_leaf_name_remote, name) + 2; |
799 | |
800 | return round_up(remotesize + nlen, XFS_ATTR_LEAF_NAME_ALIGN); |
801 | } |
802 | |
803 | static inline int xfs_attr_leaf_entsize_local(int nlen, int vlen) |
804 | { |
805 | /* |
806 | * Prior to Linux 6.5, struct xfs_attr_leaf_name_local ended with |
807 | * nameval[1], which was used as a flexarray. The layout of this |
808 | * struct is 3 bytes of fixed-length fields followed by a __u8 flex |
809 | * array at offset 3. |
810 | * |
811 | * struct xfs_attr_leaf_name_local had zero bytes of implicit padding |
812 | * at the end of the struct to make the struct length 4. On most |
813 | * architectures, after converting nameval[1] to nameval[], there is |
814 | * one implicit padding byte and the struct size remains 4. However, |
815 | * there are compiler configurations that do not add implicit padding |
816 | * at all (m68k) and would break. |
817 | * |
818 | * This entsize computation historically added (the xattr name and |
819 | * value length) to (the padded struct length - 1) and rounded that sum |
820 | * up to the nearest multiple of 4 (NAME_ALIGN). IOWs, the formula is |
821 | * round_up(3 + nlen + vlen, 4). This is encoded in the ondisk format, |
822 | * so we cannot change this. |
823 | * |
824 | * Compute the entsize from offsetof of the flexarray and manually |
825 | * adding bytes for the implicit padding. |
826 | */ |
827 | const size_t localsize = |
828 | offsetof(struct xfs_attr_leaf_name_local, nameval); |
829 | |
830 | return round_up(localsize + nlen + vlen, XFS_ATTR_LEAF_NAME_ALIGN); |
831 | } |
832 | |
833 | static inline int xfs_attr_leaf_entsize_local_max(int bsize) |
834 | { |
835 | return (((bsize) >> 1) + ((bsize) >> 2)); |
836 | } |
837 | |
838 | |
839 | |
840 | /* |
841 | * Remote attribute block format definition |
842 | * |
843 | * There is one of these headers per filesystem block in a remote attribute. |
844 | * This is done to ensure there is a 1:1 mapping between the attribute value |
845 | * length and the number of blocks needed to store the attribute. This makes the |
846 | * verification of a buffer a little more complex, but greatly simplifies the |
847 | * allocation, reading and writing of these attributes as we don't have to guess |
848 | * the number of blocks needed to store the attribute data. |
849 | */ |
850 | #define XFS_ATTR3_RMT_MAGIC 0x5841524d /* XARM */ |
851 | |
852 | struct xfs_attr3_rmt_hdr { |
853 | __be32 rm_magic; |
854 | __be32 rm_offset; |
855 | __be32 rm_bytes; |
856 | __be32 rm_crc; |
857 | uuid_t rm_uuid; |
858 | __be64 rm_owner; |
859 | __be64 rm_blkno; |
860 | __be64 rm_lsn; |
861 | }; |
862 | |
863 | #define XFS_ATTR3_RMT_CRC_OFF offsetof(struct xfs_attr3_rmt_hdr, rm_crc) |
864 | |
865 | #define XFS_ATTR3_RMT_BUF_SPACE(mp, bufsize) \ |
866 | ((bufsize) - (xfs_has_crc((mp)) ? \ |
867 | sizeof(struct xfs_attr3_rmt_hdr) : 0)) |
868 | |
869 | /* Number of bytes in a directory block. */ |
870 | static inline unsigned int xfs_dir2_dirblock_bytes(struct xfs_sb *sbp) |
871 | { |
872 | return 1 << (sbp->sb_blocklog + sbp->sb_dirblklog); |
873 | } |
874 | |
875 | xfs_failaddr_t xfs_da3_blkinfo_verify(struct xfs_buf *bp, |
876 | struct xfs_da3_blkinfo *hdr3); |
877 | |
878 | #endif /* __XFS_DA_FORMAT_H__ */ |
879 | |