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57926640 CH |
1 | /* |
2 | * Copyright (c) 2000-2001,2005 Silicon Graphics, Inc. | |
3 | * All Rights Reserved. | |
4 | * | |
5 | * This program is free software; you can redistribute it and/or | |
6 | * modify it under the terms of the GNU General Public License as | |
7 | * published by the Free Software Foundation. | |
8 | * | |
9 | * This program is distributed in the hope that it would be useful, | |
10 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
11 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
12 | * GNU General Public License for more details. | |
13 | * | |
14 | * You should have received a copy of the GNU General Public License | |
15 | * along with this program; if not, write the Free Software Foundation, | |
16 | * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA | |
17 | */ | |
18 | #ifndef __XFS_DIR2_FORMAT_H__ | |
19 | #define __XFS_DIR2_FORMAT_H__ | |
20 | ||
21 | /* | |
22 | * Directory version 2. | |
23 | * | |
24 | * There are 4 possible formats: | |
25 | * - shortform - embedded into the inode | |
26 | * - single block - data with embedded leaf at the end | |
27 | * - multiple data blocks, single leaf+freeindex block | |
28 | * - data blocks, node and leaf blocks (btree), freeindex blocks | |
29 | * | |
30 | * Note: many node blocks structures and constants are shared with the attr | |
31 | * code and defined in xfs_da_btree.h. | |
32 | */ | |
33 | ||
34 | #define XFS_DIR2_BLOCK_MAGIC 0x58443242 /* XD2B: single block dirs */ | |
35 | #define XFS_DIR2_DATA_MAGIC 0x58443244 /* XD2D: multiblock dirs */ | |
36 | #define XFS_DIR2_FREE_MAGIC 0x58443246 /* XD2F: free index blocks */ | |
37 | ||
38 | /* | |
39 | * Byte offset in data block and shortform entry. | |
40 | */ | |
41 | typedef __uint16_t xfs_dir2_data_off_t; | |
42 | #define NULLDATAOFF 0xffffU | |
43 | typedef uint xfs_dir2_data_aoff_t; /* argument form */ | |
44 | ||
45 | /* | |
46 | * Normalized offset (in a data block) of the entry, really xfs_dir2_data_off_t. | |
47 | * Only need 16 bits, this is the byte offset into the single block form. | |
48 | */ | |
49 | typedef struct { __uint8_t i[2]; } __arch_pack xfs_dir2_sf_off_t; | |
50 | ||
51 | /* | |
52 | * Offset in data space of a data entry. | |
53 | */ | |
54 | typedef __uint32_t xfs_dir2_dataptr_t; | |
55 | #define XFS_DIR2_MAX_DATAPTR ((xfs_dir2_dataptr_t)0xffffffff) | |
56 | #define XFS_DIR2_NULL_DATAPTR ((xfs_dir2_dataptr_t)0) | |
57 | ||
58 | /* | |
59 | * Byte offset in a directory. | |
60 | */ | |
61 | typedef xfs_off_t xfs_dir2_off_t; | |
62 | ||
63 | /* | |
64 | * Directory block number (logical dirblk in file) | |
65 | */ | |
66 | typedef __uint32_t xfs_dir2_db_t; | |
67 | ||
68 | /* | |
69 | * Inode number stored as 8 8-bit values. | |
70 | */ | |
71 | typedef struct { __uint8_t i[8]; } xfs_dir2_ino8_t; | |
72 | ||
73 | /* | |
74 | * Inode number stored as 4 8-bit values. | |
75 | * Works a lot of the time, when all the inode numbers in a directory | |
76 | * fit in 32 bits. | |
77 | */ | |
78 | typedef struct { __uint8_t i[4]; } xfs_dir2_ino4_t; | |
79 | ||
80 | typedef union { | |
81 | xfs_dir2_ino8_t i8; | |
82 | xfs_dir2_ino4_t i4; | |
83 | } xfs_dir2_inou_t; | |
84 | #define XFS_DIR2_MAX_SHORT_INUM ((xfs_ino_t)0xffffffffULL) | |
85 | ||
86 | /* | |
87 | * Directory layout when stored internal to an inode. | |
88 | * | |
89 | * Small directories are packed as tightly as possible so as to fit into the | |
90 | * literal area of the inode. These "shortform" directories consist of a | |
91 | * single xfs_dir2_sf_hdr header followed by zero or more xfs_dir2_sf_entry | |
92 | * structures. Due the different inode number storage size and the variable | |
93 | * length name field in the xfs_dir2_sf_entry all these structure are | |
94 | * variable length, and the accessors in this file should be used to iterate | |
95 | * over them. | |
96 | */ | |
97 | typedef struct xfs_dir2_sf_hdr { | |
98 | __uint8_t count; /* count of entries */ | |
99 | __uint8_t i8count; /* count of 8-byte inode #s */ | |
100 | xfs_dir2_inou_t parent; /* parent dir inode number */ | |
101 | } __arch_pack xfs_dir2_sf_hdr_t; | |
102 | ||
103 | typedef struct xfs_dir2_sf_entry { | |
104 | __u8 namelen; /* actual name length */ | |
105 | xfs_dir2_sf_off_t offset; /* saved offset */ | |
106 | __u8 name[]; /* name, variable size */ | |
107 | /* | |
108 | * A xfs_dir2_ino8_t or xfs_dir2_ino4_t follows here, at a | |
109 | * variable offset after the name. | |
110 | */ | |
111 | } __arch_pack xfs_dir2_sf_entry_t; | |
112 | ||
113 | static inline int xfs_dir2_sf_hdr_size(int i8count) | |
114 | { | |
115 | return sizeof(struct xfs_dir2_sf_hdr) - | |
116 | (i8count == 0) * | |
117 | (sizeof(xfs_dir2_ino8_t) - sizeof(xfs_dir2_ino4_t)); | |
118 | } | |
119 | ||
120 | static inline xfs_dir2_data_aoff_t | |
121 | xfs_dir2_sf_get_offset(xfs_dir2_sf_entry_t *sfep) | |
122 | { | |
123 | return get_unaligned_be16(&sfep->offset.i); | |
124 | } | |
125 | ||
126 | static inline void | |
127 | xfs_dir2_sf_put_offset(xfs_dir2_sf_entry_t *sfep, xfs_dir2_data_aoff_t off) | |
128 | { | |
129 | put_unaligned_be16(off, &sfep->offset.i); | |
130 | } | |
131 | ||
132 | static inline int | |
133 | xfs_dir2_sf_entsize(struct xfs_dir2_sf_hdr *hdr, int len) | |
134 | { | |
135 | return sizeof(struct xfs_dir2_sf_entry) + /* namelen + offset */ | |
136 | len + /* name */ | |
137 | (hdr->i8count ? /* ino */ | |
138 | sizeof(xfs_dir2_ino8_t) : | |
139 | sizeof(xfs_dir2_ino4_t)); | |
140 | } | |
141 | ||
142 | static inline struct xfs_dir2_sf_entry * | |
143 | xfs_dir2_sf_firstentry(struct xfs_dir2_sf_hdr *hdr) | |
144 | { | |
145 | return (struct xfs_dir2_sf_entry *) | |
146 | ((char *)hdr + xfs_dir2_sf_hdr_size(hdr->i8count)); | |
147 | } | |
148 | ||
149 | static inline struct xfs_dir2_sf_entry * | |
150 | xfs_dir2_sf_nextentry(struct xfs_dir2_sf_hdr *hdr, | |
151 | struct xfs_dir2_sf_entry *sfep) | |
152 | { | |
153 | return (struct xfs_dir2_sf_entry *) | |
154 | ((char *)sfep + xfs_dir2_sf_entsize(hdr, sfep->namelen)); | |
155 | } | |
156 | ||
157 | ||
158 | /* | |
159 | * Data block structures. | |
160 | * | |
161 | * A pure data block looks like the following drawing on disk: | |
162 | * | |
163 | * +-------------------------------------------------+ | |
164 | * | xfs_dir2_data_hdr_t | | |
165 | * +-------------------------------------------------+ | |
166 | * | xfs_dir2_data_entry_t OR xfs_dir2_data_unused_t | | |
167 | * | xfs_dir2_data_entry_t OR xfs_dir2_data_unused_t | | |
168 | * | xfs_dir2_data_entry_t OR xfs_dir2_data_unused_t | | |
169 | * | ... | | |
170 | * +-------------------------------------------------+ | |
171 | * | unused space | | |
172 | * +-------------------------------------------------+ | |
173 | * | |
174 | * As all the entries are variable size structures the accessors below should | |
175 | * be used to iterate over them. | |
176 | * | |
177 | * In addition to the pure data blocks for the data and node formats, | |
178 | * most structures are also used for the combined data/freespace "block" | |
179 | * format below. | |
180 | */ | |
181 | ||
182 | #define XFS_DIR2_DATA_ALIGN_LOG 3 /* i.e., 8 bytes */ | |
183 | #define XFS_DIR2_DATA_ALIGN (1 << XFS_DIR2_DATA_ALIGN_LOG) | |
184 | #define XFS_DIR2_DATA_FREE_TAG 0xffff | |
185 | #define XFS_DIR2_DATA_FD_COUNT 3 | |
186 | ||
187 | /* | |
188 | * Directory address space divided into sections, | |
189 | * spaces separated by 32GB. | |
190 | */ | |
191 | #define XFS_DIR2_SPACE_SIZE (1ULL << (32 + XFS_DIR2_DATA_ALIGN_LOG)) | |
192 | #define XFS_DIR2_DATA_SPACE 0 | |
193 | #define XFS_DIR2_DATA_OFFSET (XFS_DIR2_DATA_SPACE * XFS_DIR2_SPACE_SIZE) | |
194 | #define XFS_DIR2_DATA_FIRSTDB(mp) \ | |
195 | xfs_dir2_byte_to_db(mp, XFS_DIR2_DATA_OFFSET) | |
196 | ||
197 | /* | |
198 | * Offsets of . and .. in data space (always block 0) | |
199 | */ | |
200 | #define XFS_DIR2_DATA_DOT_OFFSET \ | |
201 | ((xfs_dir2_data_aoff_t)sizeof(struct xfs_dir2_data_hdr)) | |
202 | #define XFS_DIR2_DATA_DOTDOT_OFFSET \ | |
203 | (XFS_DIR2_DATA_DOT_OFFSET + xfs_dir2_data_entsize(1)) | |
204 | #define XFS_DIR2_DATA_FIRST_OFFSET \ | |
205 | (XFS_DIR2_DATA_DOTDOT_OFFSET + xfs_dir2_data_entsize(2)) | |
206 | ||
207 | /* | |
208 | * Describe a free area in the data block. | |
209 | * | |
210 | * The freespace will be formatted as a xfs_dir2_data_unused_t. | |
211 | */ | |
212 | typedef struct xfs_dir2_data_free { | |
213 | __be16 offset; /* start of freespace */ | |
214 | __be16 length; /* length of freespace */ | |
215 | } xfs_dir2_data_free_t; | |
216 | ||
217 | /* | |
218 | * Header for the data blocks. | |
219 | * | |
220 | * The code knows that XFS_DIR2_DATA_FD_COUNT is 3. | |
221 | */ | |
222 | typedef struct xfs_dir2_data_hdr { | |
223 | __be32 magic; /* XFS_DIR2_DATA_MAGIC or */ | |
224 | /* XFS_DIR2_BLOCK_MAGIC */ | |
225 | xfs_dir2_data_free_t bestfree[XFS_DIR2_DATA_FD_COUNT]; | |
226 | } xfs_dir2_data_hdr_t; | |
227 | ||
228 | /* | |
229 | * Active entry in a data block. | |
230 | * | |
231 | * Aligned to 8 bytes. After the variable length name field there is a | |
232 | * 2 byte tag field, which can be accessed using xfs_dir2_data_entry_tag_p. | |
233 | */ | |
234 | typedef struct xfs_dir2_data_entry { | |
235 | __be64 inumber; /* inode number */ | |
236 | __u8 namelen; /* name length */ | |
237 | __u8 name[]; /* name bytes, no null */ | |
238 | /* __be16 tag; */ /* starting offset of us */ | |
239 | } xfs_dir2_data_entry_t; | |
240 | ||
241 | /* | |
242 | * Unused entry in a data block. | |
243 | * | |
244 | * Aligned to 8 bytes. Tag appears as the last 2 bytes and must be accessed | |
245 | * using xfs_dir2_data_unused_tag_p. | |
246 | */ | |
247 | typedef struct xfs_dir2_data_unused { | |
248 | __be16 freetag; /* XFS_DIR2_DATA_FREE_TAG */ | |
249 | __be16 length; /* total free length */ | |
250 | /* variable offset */ | |
251 | __be16 tag; /* starting offset of us */ | |
252 | } xfs_dir2_data_unused_t; | |
253 | ||
254 | /* | |
255 | * Size of a data entry. | |
256 | */ | |
257 | static inline int xfs_dir2_data_entsize(int n) | |
258 | { | |
259 | return (int)roundup(offsetof(struct xfs_dir2_data_entry, name[0]) + n + | |
260 | (uint)sizeof(xfs_dir2_data_off_t), XFS_DIR2_DATA_ALIGN); | |
261 | } | |
262 | ||
263 | /* | |
264 | * Pointer to an entry's tag word. | |
265 | */ | |
266 | static inline __be16 * | |
267 | xfs_dir2_data_entry_tag_p(struct xfs_dir2_data_entry *dep) | |
268 | { | |
269 | return (__be16 *)((char *)dep + | |
270 | xfs_dir2_data_entsize(dep->namelen) - sizeof(__be16)); | |
271 | } | |
272 | ||
273 | /* | |
274 | * Pointer to a freespace's tag word. | |
275 | */ | |
276 | static inline __be16 * | |
277 | xfs_dir2_data_unused_tag_p(struct xfs_dir2_data_unused *dup) | |
278 | { | |
279 | return (__be16 *)((char *)dup + | |
280 | be16_to_cpu(dup->length) - sizeof(__be16)); | |
281 | } | |
282 | ||
283 | /* | |
284 | * Leaf block structures. | |
285 | * | |
286 | * A pure leaf block looks like the following drawing on disk: | |
287 | * | |
288 | * +---------------------------+ | |
289 | * | xfs_dir2_leaf_hdr_t | | |
290 | * +---------------------------+ | |
291 | * | xfs_dir2_leaf_entry_t | | |
292 | * | xfs_dir2_leaf_entry_t | | |
293 | * | xfs_dir2_leaf_entry_t | | |
294 | * | xfs_dir2_leaf_entry_t | | |
295 | * | ... | | |
296 | * +---------------------------+ | |
297 | * | xfs_dir2_data_off_t | | |
298 | * | xfs_dir2_data_off_t | | |
299 | * | xfs_dir2_data_off_t | | |
300 | * | ... | | |
301 | * +---------------------------+ | |
302 | * | xfs_dir2_leaf_tail_t | | |
303 | * +---------------------------+ | |
304 | * | |
305 | * The xfs_dir2_data_off_t members (bests) and tail are at the end of the block | |
306 | * for single-leaf (magic = XFS_DIR2_LEAF1_MAGIC) blocks only, but not present | |
307 | * for directories with separate leaf nodes and free space blocks | |
308 | * (magic = XFS_DIR2_LEAFN_MAGIC). | |
309 | * | |
310 | * As all the entries are variable size structures the accessors below should | |
311 | * be used to iterate over them. | |
312 | */ | |
313 | ||
314 | /* | |
315 | * Offset of the leaf/node space. First block in this space | |
316 | * is the btree root. | |
317 | */ | |
318 | #define XFS_DIR2_LEAF_SPACE 1 | |
319 | #define XFS_DIR2_LEAF_OFFSET (XFS_DIR2_LEAF_SPACE * XFS_DIR2_SPACE_SIZE) | |
320 | #define XFS_DIR2_LEAF_FIRSTDB(mp) \ | |
321 | xfs_dir2_byte_to_db(mp, XFS_DIR2_LEAF_OFFSET) | |
322 | ||
323 | /* | |
324 | * Leaf block header. | |
325 | */ | |
326 | typedef struct xfs_dir2_leaf_hdr { | |
327 | xfs_da_blkinfo_t info; /* header for da routines */ | |
328 | __be16 count; /* count of entries */ | |
329 | __be16 stale; /* count of stale entries */ | |
330 | } xfs_dir2_leaf_hdr_t; | |
331 | ||
332 | /* | |
333 | * Leaf block entry. | |
334 | */ | |
335 | typedef struct xfs_dir2_leaf_entry { | |
336 | __be32 hashval; /* hash value of name */ | |
337 | __be32 address; /* address of data entry */ | |
338 | } xfs_dir2_leaf_entry_t; | |
339 | ||
340 | /* | |
341 | * Leaf block tail. | |
342 | */ | |
343 | typedef struct xfs_dir2_leaf_tail { | |
344 | __be32 bestcount; | |
345 | } xfs_dir2_leaf_tail_t; | |
346 | ||
347 | /* | |
348 | * Leaf block. | |
349 | */ | |
350 | typedef struct xfs_dir2_leaf { | |
351 | xfs_dir2_leaf_hdr_t hdr; /* leaf header */ | |
352 | xfs_dir2_leaf_entry_t ents[]; /* entries */ | |
353 | } xfs_dir2_leaf_t; | |
354 | ||
355 | /* | |
356 | * DB blocks here are logical directory block numbers, not filesystem blocks. | |
357 | */ | |
358 | ||
359 | static inline int xfs_dir2_max_leaf_ents(struct xfs_mount *mp) | |
360 | { | |
361 | return (mp->m_dirblksize - (uint)sizeof(struct xfs_dir2_leaf_hdr)) / | |
362 | (uint)sizeof(struct xfs_dir2_leaf_entry); | |
363 | } | |
364 | ||
365 | /* | |
366 | * Get address of the bestcount field in the single-leaf block. | |
367 | */ | |
368 | static inline struct xfs_dir2_leaf_tail * | |
369 | xfs_dir2_leaf_tail_p(struct xfs_mount *mp, struct xfs_dir2_leaf *lp) | |
370 | { | |
371 | return (struct xfs_dir2_leaf_tail *) | |
372 | ((char *)lp + mp->m_dirblksize - | |
373 | sizeof(struct xfs_dir2_leaf_tail)); | |
374 | } | |
375 | ||
376 | /* | |
377 | * Get address of the bests array in the single-leaf block. | |
378 | */ | |
379 | static inline __be16 * | |
380 | xfs_dir2_leaf_bests_p(struct xfs_dir2_leaf_tail *ltp) | |
381 | { | |
382 | return (__be16 *)ltp - be32_to_cpu(ltp->bestcount); | |
383 | } | |
384 | ||
385 | /* | |
386 | * Convert dataptr to byte in file space | |
387 | */ | |
388 | static inline xfs_dir2_off_t | |
389 | xfs_dir2_dataptr_to_byte(struct xfs_mount *mp, xfs_dir2_dataptr_t dp) | |
390 | { | |
391 | return (xfs_dir2_off_t)dp << XFS_DIR2_DATA_ALIGN_LOG; | |
392 | } | |
393 | ||
394 | /* | |
395 | * Convert byte in file space to dataptr. It had better be aligned. | |
396 | */ | |
397 | static inline xfs_dir2_dataptr_t | |
398 | xfs_dir2_byte_to_dataptr(struct xfs_mount *mp, xfs_dir2_off_t by) | |
399 | { | |
400 | return (xfs_dir2_dataptr_t)(by >> XFS_DIR2_DATA_ALIGN_LOG); | |
401 | } | |
402 | ||
403 | /* | |
404 | * Convert byte in space to (DB) block | |
405 | */ | |
406 | static inline xfs_dir2_db_t | |
407 | xfs_dir2_byte_to_db(struct xfs_mount *mp, xfs_dir2_off_t by) | |
408 | { | |
409 | return (xfs_dir2_db_t) | |
410 | (by >> (mp->m_sb.sb_blocklog + mp->m_sb.sb_dirblklog)); | |
411 | } | |
412 | ||
413 | /* | |
414 | * Convert dataptr to a block number | |
415 | */ | |
416 | static inline xfs_dir2_db_t | |
417 | xfs_dir2_dataptr_to_db(struct xfs_mount *mp, xfs_dir2_dataptr_t dp) | |
418 | { | |
419 | return xfs_dir2_byte_to_db(mp, xfs_dir2_dataptr_to_byte(mp, dp)); | |
420 | } | |
421 | ||
422 | /* | |
423 | * Convert byte in space to offset in a block | |
424 | */ | |
425 | static inline xfs_dir2_data_aoff_t | |
426 | xfs_dir2_byte_to_off(struct xfs_mount *mp, xfs_dir2_off_t by) | |
427 | { | |
428 | return (xfs_dir2_data_aoff_t)(by & | |
429 | ((1 << (mp->m_sb.sb_blocklog + mp->m_sb.sb_dirblklog)) - 1)); | |
430 | } | |
431 | ||
432 | /* | |
433 | * Convert dataptr to a byte offset in a block | |
434 | */ | |
435 | static inline xfs_dir2_data_aoff_t | |
436 | xfs_dir2_dataptr_to_off(struct xfs_mount *mp, xfs_dir2_dataptr_t dp) | |
437 | { | |
438 | return xfs_dir2_byte_to_off(mp, xfs_dir2_dataptr_to_byte(mp, dp)); | |
439 | } | |
440 | ||
441 | /* | |
442 | * Convert block and offset to byte in space | |
443 | */ | |
444 | static inline xfs_dir2_off_t | |
445 | xfs_dir2_db_off_to_byte(struct xfs_mount *mp, xfs_dir2_db_t db, | |
446 | xfs_dir2_data_aoff_t o) | |
447 | { | |
448 | return ((xfs_dir2_off_t)db << | |
449 | (mp->m_sb.sb_blocklog + mp->m_sb.sb_dirblklog)) + o; | |
450 | } | |
451 | ||
452 | /* | |
453 | * Convert block (DB) to block (dablk) | |
454 | */ | |
455 | static inline xfs_dablk_t | |
456 | xfs_dir2_db_to_da(struct xfs_mount *mp, xfs_dir2_db_t db) | |
457 | { | |
458 | return (xfs_dablk_t)(db << mp->m_sb.sb_dirblklog); | |
459 | } | |
460 | ||
461 | /* | |
462 | * Convert byte in space to (DA) block | |
463 | */ | |
464 | static inline xfs_dablk_t | |
465 | xfs_dir2_byte_to_da(struct xfs_mount *mp, xfs_dir2_off_t by) | |
466 | { | |
467 | return xfs_dir2_db_to_da(mp, xfs_dir2_byte_to_db(mp, by)); | |
468 | } | |
469 | ||
470 | /* | |
471 | * Convert block and offset to dataptr | |
472 | */ | |
473 | static inline xfs_dir2_dataptr_t | |
474 | xfs_dir2_db_off_to_dataptr(struct xfs_mount *mp, xfs_dir2_db_t db, | |
475 | xfs_dir2_data_aoff_t o) | |
476 | { | |
477 | return xfs_dir2_byte_to_dataptr(mp, xfs_dir2_db_off_to_byte(mp, db, o)); | |
478 | } | |
479 | ||
480 | /* | |
481 | * Convert block (dablk) to block (DB) | |
482 | */ | |
483 | static inline xfs_dir2_db_t | |
484 | xfs_dir2_da_to_db(struct xfs_mount *mp, xfs_dablk_t da) | |
485 | { | |
486 | return (xfs_dir2_db_t)(da >> mp->m_sb.sb_dirblklog); | |
487 | } | |
488 | ||
489 | /* | |
490 | * Convert block (dablk) to byte offset in space | |
491 | */ | |
492 | static inline xfs_dir2_off_t | |
493 | xfs_dir2_da_to_byte(struct xfs_mount *mp, xfs_dablk_t da) | |
494 | { | |
495 | return xfs_dir2_db_off_to_byte(mp, xfs_dir2_da_to_db(mp, da), 0); | |
496 | } | |
497 | ||
498 | /* | |
499 | * Free space block defintions for the node format. | |
500 | */ | |
501 | ||
502 | /* | |
503 | * Offset of the freespace index. | |
504 | */ | |
505 | #define XFS_DIR2_FREE_SPACE 2 | |
506 | #define XFS_DIR2_FREE_OFFSET (XFS_DIR2_FREE_SPACE * XFS_DIR2_SPACE_SIZE) | |
507 | #define XFS_DIR2_FREE_FIRSTDB(mp) \ | |
508 | xfs_dir2_byte_to_db(mp, XFS_DIR2_FREE_OFFSET) | |
509 | ||
510 | typedef struct xfs_dir2_free_hdr { | |
511 | __be32 magic; /* XFS_DIR2_FREE_MAGIC */ | |
512 | __be32 firstdb; /* db of first entry */ | |
513 | __be32 nvalid; /* count of valid entries */ | |
514 | __be32 nused; /* count of used entries */ | |
515 | } xfs_dir2_free_hdr_t; | |
516 | ||
517 | typedef struct xfs_dir2_free { | |
518 | xfs_dir2_free_hdr_t hdr; /* block header */ | |
a00b7745 | 519 | __be16 bests[]; /* best free counts */ |
57926640 CH |
520 | /* unused entries are -1 */ |
521 | } xfs_dir2_free_t; | |
522 | ||
a00b7745 CH |
523 | static inline int xfs_dir2_free_max_bests(struct xfs_mount *mp) |
524 | { | |
525 | return (mp->m_dirblksize - sizeof(struct xfs_dir2_free_hdr)) / | |
526 | sizeof(xfs_dir2_data_off_t); | |
527 | } | |
57926640 CH |
528 | |
529 | /* | |
530 | * Convert data space db to the corresponding free db. | |
531 | */ | |
532 | static inline xfs_dir2_db_t | |
533 | xfs_dir2_db_to_fdb(struct xfs_mount *mp, xfs_dir2_db_t db) | |
534 | { | |
a00b7745 | 535 | return XFS_DIR2_FREE_FIRSTDB(mp) + db / xfs_dir2_free_max_bests(mp); |
57926640 CH |
536 | } |
537 | ||
538 | /* | |
539 | * Convert data space db to the corresponding index in a free db. | |
540 | */ | |
541 | static inline int | |
542 | xfs_dir2_db_to_fdindex(struct xfs_mount *mp, xfs_dir2_db_t db) | |
543 | { | |
a00b7745 | 544 | return db % xfs_dir2_free_max_bests(mp); |
57926640 CH |
545 | } |
546 | ||
547 | /* | |
548 | * Single block format. | |
549 | * | |
550 | * The single block format looks like the following drawing on disk: | |
551 | * | |
552 | * +-------------------------------------------------+ | |
553 | * | xfs_dir2_data_hdr_t | | |
554 | * +-------------------------------------------------+ | |
555 | * | xfs_dir2_data_entry_t OR xfs_dir2_data_unused_t | | |
556 | * | xfs_dir2_data_entry_t OR xfs_dir2_data_unused_t | | |
557 | * | xfs_dir2_data_entry_t OR xfs_dir2_data_unused_t : | |
558 | * | ... | | |
559 | * +-------------------------------------------------+ | |
560 | * | unused space | | |
561 | * +-------------------------------------------------+ | |
562 | * | ... | | |
563 | * | xfs_dir2_leaf_entry_t | | |
564 | * | xfs_dir2_leaf_entry_t | | |
565 | * +-------------------------------------------------+ | |
566 | * | xfs_dir2_block_tail_t | | |
567 | * +-------------------------------------------------+ | |
568 | * | |
569 | * As all the entries are variable size structures the accessors below should | |
570 | * be used to iterate over them. | |
571 | */ | |
572 | ||
573 | typedef struct xfs_dir2_block_tail { | |
574 | __be32 count; /* count of leaf entries */ | |
575 | __be32 stale; /* count of stale lf entries */ | |
576 | } xfs_dir2_block_tail_t; | |
577 | ||
578 | /* | |
579 | * Pointer to the leaf header embedded in a data block (1-block format) | |
580 | */ | |
581 | static inline struct xfs_dir2_block_tail * | |
582 | xfs_dir2_block_tail_p(struct xfs_mount *mp, struct xfs_dir2_data_hdr *hdr) | |
583 | { | |
584 | return ((struct xfs_dir2_block_tail *) | |
585 | ((char *)hdr + mp->m_dirblksize)) - 1; | |
586 | } | |
587 | ||
588 | /* | |
589 | * Pointer to the leaf entries embedded in a data block (1-block format) | |
590 | */ | |
591 | static inline struct xfs_dir2_leaf_entry * | |
592 | xfs_dir2_block_leaf_p(struct xfs_dir2_block_tail *btp) | |
593 | { | |
594 | return ((struct xfs_dir2_leaf_entry *)btp) - be32_to_cpu(btp->count); | |
595 | } | |
596 | ||
597 | #endif /* __XFS_DIR2_FORMAT_H__ */ |