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: v2 dirlf single blks */
39 #define XFS_DIR3_LEAFN_MAGIC 0x3dff /* magic number: v2 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 * In-core version of the node header to abstract the differences in the v2 and
98 * v3 disk format of the headers. Callers need to convert to/from disk format as
99 * appropriate.
100 */
101 struct xfs_da3_icnode_hdr {
102 uint32_t forw;
103 uint32_t back;
104 uint16_t magic;
105 uint16_t count;
106 uint16_t level;
107 };
108
109 /*
110 * Directory version 2.
111 *
112 * There are 4 possible formats:
113 * - shortform - embedded into the inode
114 * - single block - data with embedded leaf at the end
115 * - multiple data blocks, single leaf+freeindex block
116 * - data blocks, node and leaf blocks (btree), freeindex blocks
117 *
118 * Note: many node blocks structures and constants are shared with the attr
119 * code and defined in xfs_da_btree.h.
120 */
121
122 #define XFS_DIR2_BLOCK_MAGIC 0x58443242 /* XD2B: single block dirs */
123 #define XFS_DIR2_DATA_MAGIC 0x58443244 /* XD2D: multiblock dirs */
124 #define XFS_DIR2_FREE_MAGIC 0x58443246 /* XD2F: free index blocks */
125
126 /*
127 * Directory Version 3 With CRCs.
128 *
129 * The tree formats are the same as for version 2 directories. The difference
130 * is in the block header and dirent formats. In many cases the v3 structures
131 * use v2 definitions as they are no different and this makes code sharing much
132 * easier.
133 *
134 * Also, the xfs_dir3_*() functions handle both v2 and v3 formats - if the
135 * format is v2 then they switch to the existing v2 code, or the format is v3
136 * they implement the v3 functionality. This means the existing dir2 is a mix of
137 * xfs_dir2/xfs_dir3 calls and functions. The xfs_dir3 functions are called
138 * where there is a difference in the formats, otherwise the code is unchanged.
139 *
140 * Where it is possible, the code decides what to do based on the magic numbers
141 * in the blocks rather than feature bits in the superblock. This means the code
142 * is as independent of the external XFS code as possible as doesn't require
143 * passing struct xfs_mount pointers into places where it isn't really
144 * necessary.
145 *
146 * Version 3 includes:
147 *
148 * - a larger block header for CRC and identification purposes and so the
149 * offsets of all the structures inside the blocks are different.
150 *
151 * - new magic numbers to be able to detect the v2/v3 types on the fly.
152 */
153
154 #define XFS_DIR3_BLOCK_MAGIC 0x58444233 /* XDB3: single block dirs */
155 #define XFS_DIR3_DATA_MAGIC 0x58444433 /* XDD3: multiblock dirs */
156 #define XFS_DIR3_FREE_MAGIC 0x58444633 /* XDF3: free index blocks */
157
158 /*
159 * Dirents in version 3 directories have a file type field. Additions to this
160 * list are an on-disk format change, requiring feature bits. Valid values
161 * are as follows:
162 */
163 #define XFS_DIR3_FT_UNKNOWN 0
164 #define XFS_DIR3_FT_REG_FILE 1
165 #define XFS_DIR3_FT_DIR 2
166 #define XFS_DIR3_FT_CHRDEV 3
167 #define XFS_DIR3_FT_BLKDEV 4
168 #define XFS_DIR3_FT_FIFO 5
169 #define XFS_DIR3_FT_SOCK 6
170 #define XFS_DIR3_FT_SYMLINK 7
171 #define XFS_DIR3_FT_WHT 8
172
173 #define XFS_DIR3_FT_MAX 9
174
175 /*
176 * Byte offset in data block and shortform entry.
177 */
178 typedef uint16_t xfs_dir2_data_off_t;
179 #define NULLDATAOFF 0xffffU
180 typedef uint xfs_dir2_data_aoff_t; /* argument form */
181
182 /*
183 * Offset in data space of a data entry.
184 */
185 typedef uint32_t xfs_dir2_dataptr_t;
186 #define XFS_DIR2_MAX_DATAPTR ((xfs_dir2_dataptr_t)0xffffffff)
187 #define XFS_DIR2_NULL_DATAPTR ((xfs_dir2_dataptr_t)0)
188
189 /*
190 * Byte offset in a directory.
191 */
192 typedef xfs_off_t xfs_dir2_off_t;
193
194 /*
195 * Directory block number (logical dirblk in file)
196 */
197 typedef uint32_t xfs_dir2_db_t;
198
199 #define XFS_INO32_SIZE 4
200 #define XFS_INO64_SIZE 8
201 #define XFS_INO64_DIFF (XFS_INO64_SIZE - XFS_INO32_SIZE)
202
203 #define XFS_DIR2_MAX_SHORT_INUM ((xfs_ino_t)0xffffffffULL)
204
205 /*
206 * Directory layout when stored internal to an inode.
207 *
208 * Small directories are packed as tightly as possible so as to fit into the
209 * literal area of the inode. These "shortform" directories consist of a
210 * single xfs_dir2_sf_hdr header followed by zero or more xfs_dir2_sf_entry
211 * structures. Due the different inode number storage size and the variable
212 * length name field in the xfs_dir2_sf_entry all these structure are
213 * variable length, and the accessors in this file should be used to iterate
214 * over them.
215 */
216 typedef struct xfs_dir2_sf_hdr {
217 uint8_t count; /* count of entries */
218 uint8_t i8count; /* count of 8-byte inode #s */
219 uint8_t parent[8]; /* parent dir inode number */
220 } __packed xfs_dir2_sf_hdr_t;
221
222 typedef struct xfs_dir2_sf_entry {
223 __u8 namelen; /* actual name length */
224 __u8 offset[2]; /* saved offset */
225 __u8 name[]; /* name, variable size */
226 /*
227 * A single byte containing the file type field follows the inode
228 * number for version 3 directory entries.
229 *
230 * A 64-bit or 32-bit inode number follows here, at a variable offset
231 * after the name.
232 */
233 } xfs_dir2_sf_entry_t;
234
xfs_dir2_sf_hdr_size(int i8count)235 static inline int xfs_dir2_sf_hdr_size(int i8count)
236 {
237 return sizeof(struct xfs_dir2_sf_hdr) -
238 (i8count == 0) * XFS_INO64_DIFF;
239 }
240
241 static inline xfs_dir2_data_aoff_t
xfs_dir2_sf_get_offset(xfs_dir2_sf_entry_t * sfep)242 xfs_dir2_sf_get_offset(xfs_dir2_sf_entry_t *sfep)
243 {
244 return get_unaligned_be16(sfep->offset);
245 }
246
247 static inline void
xfs_dir2_sf_put_offset(xfs_dir2_sf_entry_t * sfep,xfs_dir2_data_aoff_t off)248 xfs_dir2_sf_put_offset(xfs_dir2_sf_entry_t *sfep, xfs_dir2_data_aoff_t off)
249 {
250 put_unaligned_be16(off, sfep->offset);
251 }
252
253 static inline struct xfs_dir2_sf_entry *
xfs_dir2_sf_firstentry(struct xfs_dir2_sf_hdr * hdr)254 xfs_dir2_sf_firstentry(struct xfs_dir2_sf_hdr *hdr)
255 {
256 return (struct xfs_dir2_sf_entry *)
257 ((char *)hdr + xfs_dir2_sf_hdr_size(hdr->i8count));
258 }
259
260 /*
261 * Data block structures.
262 *
263 * A pure data block looks like the following drawing on disk:
264 *
265 * +-------------------------------------------------+
266 * | xfs_dir2_data_hdr_t |
267 * +-------------------------------------------------+
268 * | xfs_dir2_data_entry_t OR xfs_dir2_data_unused_t |
269 * | xfs_dir2_data_entry_t OR xfs_dir2_data_unused_t |
270 * | xfs_dir2_data_entry_t OR xfs_dir2_data_unused_t |
271 * | ... |
272 * +-------------------------------------------------+
273 * | unused space |
274 * +-------------------------------------------------+
275 *
276 * As all the entries are variable size structures the accessors below should
277 * be used to iterate over them.
278 *
279 * In addition to the pure data blocks for the data and node formats,
280 * most structures are also used for the combined data/freespace "block"
281 * format below.
282 */
283
284 #define XFS_DIR2_DATA_ALIGN_LOG 3 /* i.e., 8 bytes */
285 #define XFS_DIR2_DATA_ALIGN (1 << XFS_DIR2_DATA_ALIGN_LOG)
286 #define XFS_DIR2_DATA_FREE_TAG 0xffff
287 #define XFS_DIR2_DATA_FD_COUNT 3
288
289 /*
290 * Directory address space divided into sections,
291 * spaces separated by 32GB.
292 */
293 #define XFS_DIR2_SPACE_SIZE (1ULL << (32 + XFS_DIR2_DATA_ALIGN_LOG))
294 #define XFS_DIR2_DATA_SPACE 0
295 #define XFS_DIR2_DATA_OFFSET (XFS_DIR2_DATA_SPACE * XFS_DIR2_SPACE_SIZE)
296
297 /*
298 * Describe a free area in the data block.
299 *
300 * The freespace will be formatted as a xfs_dir2_data_unused_t.
301 */
302 typedef struct xfs_dir2_data_free {
303 __be16 offset; /* start of freespace */
304 __be16 length; /* length of freespace */
305 } xfs_dir2_data_free_t;
306
307 /*
308 * Header for the data blocks.
309 *
310 * The code knows that XFS_DIR2_DATA_FD_COUNT is 3.
311 */
312 typedef struct xfs_dir2_data_hdr {
313 __be32 magic; /* XFS_DIR2_DATA_MAGIC or */
314 /* XFS_DIR2_BLOCK_MAGIC */
315 xfs_dir2_data_free_t bestfree[XFS_DIR2_DATA_FD_COUNT];
316 } xfs_dir2_data_hdr_t;
317
318 /*
319 * define a structure for all the verification fields we are adding to the
320 * directory block structures. This will be used in several structures.
321 * The magic number must be the first entry to align with all the dir2
322 * structures so we determine how to decode them just by the magic number.
323 */
324 struct xfs_dir3_blk_hdr {
325 __be32 magic; /* magic number */
326 __be32 crc; /* CRC of block */
327 __be64 blkno; /* first block of the buffer */
328 __be64 lsn; /* sequence number of last write */
329 uuid_t uuid; /* filesystem we belong to */
330 __be64 owner; /* inode that owns the block */
331 };
332
333 struct xfs_dir3_data_hdr {
334 struct xfs_dir3_blk_hdr hdr;
335 xfs_dir2_data_free_t best_free[XFS_DIR2_DATA_FD_COUNT];
336 __be32 pad; /* 64 bit alignment */
337 };
338
339 #define XFS_DIR3_DATA_CRC_OFF offsetof(struct xfs_dir3_data_hdr, hdr.crc)
340
341 /*
342 * Active entry in a data block.
343 *
344 * Aligned to 8 bytes. After the variable length name field there is a
345 * 2 byte tag field, which can be accessed using xfs_dir3_data_entry_tag_p.
346 *
347 * For dir3 structures, there is file type field between the name and the tag.
348 * This can only be manipulated by helper functions. It is packed hard against
349 * the end of the name so any padding for rounding is between the file type and
350 * the tag.
351 */
352 typedef struct xfs_dir2_data_entry {
353 __be64 inumber; /* inode number */
354 __u8 namelen; /* name length */
355 __u8 name[]; /* name bytes, no null */
356 /* __u8 filetype; */ /* type of inode we point to */
357 /* __be16 tag; */ /* starting offset of us */
358 } xfs_dir2_data_entry_t;
359
360 /*
361 * Unused entry in a data block.
362 *
363 * Aligned to 8 bytes. Tag appears as the last 2 bytes and must be accessed
364 * using xfs_dir2_data_unused_tag_p.
365 */
366 typedef struct xfs_dir2_data_unused {
367 __be16 freetag; /* XFS_DIR2_DATA_FREE_TAG */
368 __be16 length; /* total free length */
369 /* variable offset */
370 __be16 tag; /* starting offset of us */
371 } xfs_dir2_data_unused_t;
372
373 /*
374 * Pointer to a freespace's tag word.
375 */
376 static inline __be16 *
xfs_dir2_data_unused_tag_p(struct xfs_dir2_data_unused * dup)377 xfs_dir2_data_unused_tag_p(struct xfs_dir2_data_unused *dup)
378 {
379 return (__be16 *)((char *)dup +
380 be16_to_cpu(dup->length) - sizeof(__be16));
381 }
382
383 /*
384 * Leaf block structures.
385 *
386 * A pure leaf block looks like the following drawing on disk:
387 *
388 * +---------------------------+
389 * | xfs_dir2_leaf_hdr_t |
390 * +---------------------------+
391 * | xfs_dir2_leaf_entry_t |
392 * | xfs_dir2_leaf_entry_t |
393 * | xfs_dir2_leaf_entry_t |
394 * | xfs_dir2_leaf_entry_t |
395 * | ... |
396 * +---------------------------+
397 * | xfs_dir2_data_off_t |
398 * | xfs_dir2_data_off_t |
399 * | xfs_dir2_data_off_t |
400 * | ... |
401 * +---------------------------+
402 * | xfs_dir2_leaf_tail_t |
403 * +---------------------------+
404 *
405 * The xfs_dir2_data_off_t members (bests) and tail are at the end of the block
406 * for single-leaf (magic = XFS_DIR2_LEAF1_MAGIC) blocks only, but not present
407 * for directories with separate leaf nodes and free space blocks
408 * (magic = XFS_DIR2_LEAFN_MAGIC).
409 *
410 * As all the entries are variable size structures the accessors below should
411 * be used to iterate over them.
412 */
413
414 /*
415 * Offset of the leaf/node space. First block in this space
416 * is the btree root.
417 */
418 #define XFS_DIR2_LEAF_SPACE 1
419 #define XFS_DIR2_LEAF_OFFSET (XFS_DIR2_LEAF_SPACE * XFS_DIR2_SPACE_SIZE)
420
421 /*
422 * Leaf block header.
423 */
424 typedef struct xfs_dir2_leaf_hdr {
425 xfs_da_blkinfo_t info; /* header for da routines */
426 __be16 count; /* count of entries */
427 __be16 stale; /* count of stale entries */
428 } xfs_dir2_leaf_hdr_t;
429
430 struct xfs_dir3_leaf_hdr {
431 struct xfs_da3_blkinfo info; /* header for da routines */
432 __be16 count; /* count of entries */
433 __be16 stale; /* count of stale entries */
434 __be32 pad; /* 64 bit alignment */
435 };
436
437 struct xfs_dir3_icleaf_hdr {
438 uint32_t forw;
439 uint32_t back;
440 uint16_t magic;
441 uint16_t count;
442 uint16_t stale;
443 };
444
445 /*
446 * Leaf block entry.
447 */
448 typedef struct xfs_dir2_leaf_entry {
449 __be32 hashval; /* hash value of name */
450 __be32 address; /* address of data entry */
451 } xfs_dir2_leaf_entry_t;
452
453 /*
454 * Leaf block tail.
455 */
456 typedef struct xfs_dir2_leaf_tail {
457 __be32 bestcount;
458 } xfs_dir2_leaf_tail_t;
459
460 /*
461 * Leaf block.
462 */
463 typedef struct xfs_dir2_leaf {
464 xfs_dir2_leaf_hdr_t hdr; /* leaf header */
465 xfs_dir2_leaf_entry_t __ents[]; /* entries */
466 } xfs_dir2_leaf_t;
467
468 struct xfs_dir3_leaf {
469 struct xfs_dir3_leaf_hdr hdr; /* leaf header */
470 struct xfs_dir2_leaf_entry __ents[]; /* entries */
471 };
472
473 #define XFS_DIR3_LEAF_CRC_OFF offsetof(struct xfs_dir3_leaf_hdr, info.crc)
474
475 /*
476 * Get address of the bests array in the single-leaf block.
477 */
478 static inline __be16 *
xfs_dir2_leaf_bests_p(struct xfs_dir2_leaf_tail * ltp)479 xfs_dir2_leaf_bests_p(struct xfs_dir2_leaf_tail *ltp)
480 {
481 return (__be16 *)ltp - be32_to_cpu(ltp->bestcount);
482 }
483
484 /*
485 * Free space block defintions for the node format.
486 */
487
488 /*
489 * Offset of the freespace index.
490 */
491 #define XFS_DIR2_FREE_SPACE 2
492 #define XFS_DIR2_FREE_OFFSET (XFS_DIR2_FREE_SPACE * XFS_DIR2_SPACE_SIZE)
493
494 typedef struct xfs_dir2_free_hdr {
495 __be32 magic; /* XFS_DIR2_FREE_MAGIC */
496 __be32 firstdb; /* db of first entry */
497 __be32 nvalid; /* count of valid entries */
498 __be32 nused; /* count of used entries */
499 } xfs_dir2_free_hdr_t;
500
501 typedef struct xfs_dir2_free {
502 xfs_dir2_free_hdr_t hdr; /* block header */
503 __be16 bests[]; /* best free counts */
504 /* unused entries are -1 */
505 } xfs_dir2_free_t;
506
507 struct xfs_dir3_free_hdr {
508 struct xfs_dir3_blk_hdr hdr;
509 __be32 firstdb; /* db of first entry */
510 __be32 nvalid; /* count of valid entries */
511 __be32 nused; /* count of used entries */
512 __be32 pad; /* 64 bit alignment */
513 };
514
515 struct xfs_dir3_free {
516 struct xfs_dir3_free_hdr hdr;
517 __be16 bests[]; /* best free counts */
518 /* unused entries are -1 */
519 };
520
521 #define XFS_DIR3_FREE_CRC_OFF offsetof(struct xfs_dir3_free, hdr.hdr.crc)
522
523 /*
524 * In core version of the free block header, abstracted away from on-disk format
525 * differences. Use this in the code, and convert to/from the disk version using
526 * xfs_dir3_free_hdr_from_disk/xfs_dir3_free_hdr_to_disk.
527 */
528 struct xfs_dir3_icfree_hdr {
529 uint32_t magic;
530 uint32_t firstdb;
531 uint32_t nvalid;
532 uint32_t nused;
533
534 };
535
536 /*
537 * Single block format.
538 *
539 * The single block format looks like the following drawing on disk:
540 *
541 * +-------------------------------------------------+
542 * | xfs_dir2_data_hdr_t |
543 * +-------------------------------------------------+
544 * | xfs_dir2_data_entry_t OR xfs_dir2_data_unused_t |
545 * | xfs_dir2_data_entry_t OR xfs_dir2_data_unused_t |
546 * | xfs_dir2_data_entry_t OR xfs_dir2_data_unused_t :
547 * | ... |
548 * +-------------------------------------------------+
549 * | unused space |
550 * +-------------------------------------------------+
551 * | ... |
552 * | xfs_dir2_leaf_entry_t |
553 * | xfs_dir2_leaf_entry_t |
554 * +-------------------------------------------------+
555 * | xfs_dir2_block_tail_t |
556 * +-------------------------------------------------+
557 *
558 * As all the entries are variable size structures the accessors below should
559 * be used to iterate over them.
560 */
561
562 typedef struct xfs_dir2_block_tail {
563 __be32 count; /* count of leaf entries */
564 __be32 stale; /* count of stale lf entries */
565 } xfs_dir2_block_tail_t;
566
567 /*
568 * Pointer to the leaf entries embedded in a data block (1-block format)
569 */
570 static inline struct xfs_dir2_leaf_entry *
xfs_dir2_block_leaf_p(struct xfs_dir2_block_tail * btp)571 xfs_dir2_block_leaf_p(struct xfs_dir2_block_tail *btp)
572 {
573 return ((struct xfs_dir2_leaf_entry *)btp) - be32_to_cpu(btp->count);
574 }
575
576
577 /*
578 * Attribute storage layout
579 *
580 * Attribute lists are structured around Btrees where all the data
581 * elements are in the leaf nodes. Attribute names are hashed into an int,
582 * then that int is used as the index into the Btree. Since the hashval
583 * of an attribute name may not be unique, we may have duplicate keys. The
584 * internal links in the Btree are logical block offsets into the file.
585 *
586 * Struct leaf_entry's are packed from the top. Name/values grow from the
587 * bottom but are not packed. The freemap contains run-length-encoded entries
588 * for the free bytes after the leaf_entry's, but only the N largest such,
589 * smaller runs are dropped. When the freemap doesn't show enough space
590 * for an allocation, we compact the name/value area and try again. If we
591 * still don't have enough space, then we have to split the block. The
592 * name/value structs (both local and remote versions) must be 32bit aligned.
593 *
594 * Since we have duplicate hash keys, for each key that matches, compare
595 * the actual name string. The root and intermediate node search always
596 * takes the first-in-the-block key match found, so we should only have
597 * to work "forw"ard. If none matches, continue with the "forw"ard leaf
598 * nodes until the hash key changes or the attribute name is found.
599 *
600 * We store the fact that an attribute is a ROOT/USER/SECURE attribute in
601 * the leaf_entry. The namespaces are independent only because we also look
602 * at the namespace bit when we are looking for a matching attribute name.
603 *
604 * We also store an "incomplete" bit in the leaf_entry. It shows that an
605 * attribute is in the middle of being created and should not be shown to
606 * the user if we crash during the time that the bit is set. We clear the
607 * bit when we have finished setting up the attribute. We do this because
608 * we cannot create some large attributes inside a single transaction, and we
609 * need some indication that we weren't finished if we crash in the middle.
610 */
611 #define XFS_ATTR_LEAF_MAPSIZE 3 /* how many freespace slots */
612
613 /*
614 * Entries are packed toward the top as tight as possible.
615 */
616 typedef struct xfs_attr_shortform {
617 struct xfs_attr_sf_hdr { /* constant-structure header block */
618 __be16 totsize; /* total bytes in shortform list */
619 __u8 count; /* count of active entries */
620 __u8 padding;
621 } hdr;
622 struct xfs_attr_sf_entry {
623 uint8_t namelen; /* actual length of name (no NULL) */
624 uint8_t valuelen; /* actual length of value (no NULL) */
625 uint8_t flags; /* flags bits (see xfs_attr_leaf.h) */
626 uint8_t nameval[1]; /* name & value bytes concatenated */
627 } list[1]; /* variable sized array */
628 } xfs_attr_shortform_t;
629
630 typedef struct xfs_attr_leaf_map { /* RLE map of free bytes */
631 __be16 base; /* base of free region */
632 __be16 size; /* length of free region */
633 } xfs_attr_leaf_map_t;
634
635 typedef struct xfs_attr_leaf_hdr { /* constant-structure header block */
636 xfs_da_blkinfo_t info; /* block type, links, etc. */
637 __be16 count; /* count of active leaf_entry's */
638 __be16 usedbytes; /* num bytes of names/values stored */
639 __be16 firstused; /* first used byte in name area */
640 __u8 holes; /* != 0 if blk needs compaction */
641 __u8 pad1;
642 xfs_attr_leaf_map_t freemap[XFS_ATTR_LEAF_MAPSIZE];
643 /* N largest free regions */
644 } xfs_attr_leaf_hdr_t;
645
646 typedef struct xfs_attr_leaf_entry { /* sorted on key, not name */
647 __be32 hashval; /* hash value of name */
648 __be16 nameidx; /* index into buffer of name/value */
649 __u8 flags; /* LOCAL/ROOT/SECURE/INCOMPLETE flag */
650 __u8 pad2; /* unused pad byte */
651 } xfs_attr_leaf_entry_t;
652
653 typedef struct xfs_attr_leaf_name_local {
654 __be16 valuelen; /* number of bytes in value */
655 __u8 namelen; /* length of name bytes */
656 __u8 nameval[1]; /* name/value bytes */
657 } xfs_attr_leaf_name_local_t;
658
659 typedef struct xfs_attr_leaf_name_remote {
660 __be32 valueblk; /* block number of value bytes */
661 __be32 valuelen; /* number of bytes in value */
662 __u8 namelen; /* length of name bytes */
663 __u8 name[1]; /* name bytes */
664 } xfs_attr_leaf_name_remote_t;
665
666 typedef struct xfs_attr_leafblock {
667 xfs_attr_leaf_hdr_t hdr; /* constant-structure header block */
668 xfs_attr_leaf_entry_t entries[1]; /* sorted on key, not name */
669 /*
670 * The rest of the block contains the following structures after the
671 * leaf entries, growing from the bottom up. The variables are never
672 * referenced and definining them can actually make gcc optimize away
673 * accesses to the 'entries' array above index 0 so don't do that.
674 *
675 * xfs_attr_leaf_name_local_t namelist;
676 * xfs_attr_leaf_name_remote_t valuelist;
677 */
678 } xfs_attr_leafblock_t;
679
680 /*
681 * CRC enabled leaf structures. Called "version 3" structures to match the
682 * version number of the directory and dablk structures for this feature, and
683 * attr2 is already taken by the variable inode attribute fork size feature.
684 */
685 struct xfs_attr3_leaf_hdr {
686 struct xfs_da3_blkinfo info;
687 __be16 count;
688 __be16 usedbytes;
689 __be16 firstused;
690 __u8 holes;
691 __u8 pad1;
692 struct xfs_attr_leaf_map freemap[XFS_ATTR_LEAF_MAPSIZE];
693 __be32 pad2; /* 64 bit alignment */
694 };
695
696 #define XFS_ATTR3_LEAF_CRC_OFF (offsetof(struct xfs_attr3_leaf_hdr, info.crc))
697
698 struct xfs_attr3_leafblock {
699 struct xfs_attr3_leaf_hdr hdr;
700 struct xfs_attr_leaf_entry entries[1];
701
702 /*
703 * The rest of the block contains the following structures after the
704 * leaf entries, growing from the bottom up. The variables are never
705 * referenced, the locations accessed purely from helper functions.
706 *
707 * struct xfs_attr_leaf_name_local
708 * struct xfs_attr_leaf_name_remote
709 */
710 };
711
712 /*
713 * incore, neutral version of the attribute leaf header
714 */
715 struct xfs_attr3_icleaf_hdr {
716 uint32_t forw;
717 uint32_t back;
718 uint16_t magic;
719 uint16_t count;
720 uint16_t usedbytes;
721 /*
722 * firstused is 32-bit here instead of 16-bit like the on-disk variant
723 * to support maximum fsb size of 64k without overflow issues throughout
724 * the attr code. Instead, the overflow condition is handled on
725 * conversion to/from disk.
726 */
727 uint32_t firstused;
728 __u8 holes;
729 struct {
730 uint16_t base;
731 uint16_t size;
732 } freemap[XFS_ATTR_LEAF_MAPSIZE];
733 };
734
735 /*
736 * Special value to represent fs block size in the leaf header firstused field.
737 * Only used when block size overflows the 2-bytes available on disk.
738 */
739 #define XFS_ATTR3_LEAF_NULLOFF 0
740
741 /*
742 * Flags used in the leaf_entry[i].flags field.
743 * NOTE: the INCOMPLETE bit must not collide with the flags bits specified
744 * on the system call, they are "or"ed together for various operations.
745 */
746 #define XFS_ATTR_LOCAL_BIT 0 /* attr is stored locally */
747 #define XFS_ATTR_ROOT_BIT 1 /* limit access to trusted attrs */
748 #define XFS_ATTR_SECURE_BIT 2 /* limit access to secure attrs */
749 #define XFS_ATTR_INCOMPLETE_BIT 7 /* attr in middle of create/delete */
750 #define XFS_ATTR_LOCAL (1 << XFS_ATTR_LOCAL_BIT)
751 #define XFS_ATTR_ROOT (1 << XFS_ATTR_ROOT_BIT)
752 #define XFS_ATTR_SECURE (1 << XFS_ATTR_SECURE_BIT)
753 #define XFS_ATTR_INCOMPLETE (1 << XFS_ATTR_INCOMPLETE_BIT)
754
755 /*
756 * Conversion macros for converting namespace bits from argument flags
757 * to ondisk flags.
758 */
759 #define XFS_ATTR_NSP_ARGS_MASK (ATTR_ROOT | ATTR_SECURE)
760 #define XFS_ATTR_NSP_ONDISK_MASK (XFS_ATTR_ROOT | XFS_ATTR_SECURE)
761 #define XFS_ATTR_NSP_ONDISK(flags) ((flags) & XFS_ATTR_NSP_ONDISK_MASK)
762 #define XFS_ATTR_NSP_ARGS(flags) ((flags) & XFS_ATTR_NSP_ARGS_MASK)
763 #define XFS_ATTR_NSP_ARGS_TO_ONDISK(x) (((x) & ATTR_ROOT ? XFS_ATTR_ROOT : 0) |\
764 ((x) & ATTR_SECURE ? XFS_ATTR_SECURE : 0))
765 #define XFS_ATTR_NSP_ONDISK_TO_ARGS(x) (((x) & XFS_ATTR_ROOT ? ATTR_ROOT : 0) |\
766 ((x) & XFS_ATTR_SECURE ? ATTR_SECURE : 0))
767
768 /*
769 * Alignment for namelist and valuelist entries (since they are mixed
770 * there can be only one alignment value)
771 */
772 #define XFS_ATTR_LEAF_NAME_ALIGN ((uint)sizeof(xfs_dablk_t))
773
774 static inline int
xfs_attr3_leaf_hdr_size(struct xfs_attr_leafblock * leafp)775 xfs_attr3_leaf_hdr_size(struct xfs_attr_leafblock *leafp)
776 {
777 if (leafp->hdr.info.magic == cpu_to_be16(XFS_ATTR3_LEAF_MAGIC))
778 return sizeof(struct xfs_attr3_leaf_hdr);
779 return sizeof(struct xfs_attr_leaf_hdr);
780 }
781
782 static inline struct xfs_attr_leaf_entry *
xfs_attr3_leaf_entryp(xfs_attr_leafblock_t * leafp)783 xfs_attr3_leaf_entryp(xfs_attr_leafblock_t *leafp)
784 {
785 if (leafp->hdr.info.magic == cpu_to_be16(XFS_ATTR3_LEAF_MAGIC))
786 return &((struct xfs_attr3_leafblock *)leafp)->entries[0];
787 return &leafp->entries[0];
788 }
789
790 /*
791 * Cast typed pointers for "local" and "remote" name/value structs.
792 */
793 static inline char *
xfs_attr3_leaf_name(xfs_attr_leafblock_t * leafp,int idx)794 xfs_attr3_leaf_name(xfs_attr_leafblock_t *leafp, int idx)
795 {
796 struct xfs_attr_leaf_entry *entries = xfs_attr3_leaf_entryp(leafp);
797
798 return &((char *)leafp)[be16_to_cpu(entries[idx].nameidx)];
799 }
800
801 static inline xfs_attr_leaf_name_remote_t *
xfs_attr3_leaf_name_remote(xfs_attr_leafblock_t * leafp,int idx)802 xfs_attr3_leaf_name_remote(xfs_attr_leafblock_t *leafp, int idx)
803 {
804 return (xfs_attr_leaf_name_remote_t *)xfs_attr3_leaf_name(leafp, idx);
805 }
806
807 static inline xfs_attr_leaf_name_local_t *
xfs_attr3_leaf_name_local(xfs_attr_leafblock_t * leafp,int idx)808 xfs_attr3_leaf_name_local(xfs_attr_leafblock_t *leafp, int idx)
809 {
810 return (xfs_attr_leaf_name_local_t *)xfs_attr3_leaf_name(leafp, idx);
811 }
812
813 /*
814 * Calculate total bytes used (including trailing pad for alignment) for
815 * a "local" name/value structure, a "remote" name/value structure, and
816 * a pointer which might be either.
817 */
xfs_attr_leaf_entsize_remote(int nlen)818 static inline int xfs_attr_leaf_entsize_remote(int nlen)
819 {
820 return ((uint)sizeof(xfs_attr_leaf_name_remote_t) - 1 + (nlen) + \
821 XFS_ATTR_LEAF_NAME_ALIGN - 1) & ~(XFS_ATTR_LEAF_NAME_ALIGN - 1);
822 }
823
xfs_attr_leaf_entsize_local(int nlen,int vlen)824 static inline int xfs_attr_leaf_entsize_local(int nlen, int vlen)
825 {
826 return ((uint)sizeof(xfs_attr_leaf_name_local_t) - 1 + (nlen) + (vlen) +
827 XFS_ATTR_LEAF_NAME_ALIGN - 1) & ~(XFS_ATTR_LEAF_NAME_ALIGN - 1);
828 }
829
xfs_attr_leaf_entsize_local_max(int bsize)830 static inline int xfs_attr_leaf_entsize_local_max(int bsize)
831 {
832 return (((bsize) >> 1) + ((bsize) >> 2));
833 }
834
835
836
837 /*
838 * Remote attribute block format definition
839 *
840 * There is one of these headers per filesystem block in a remote attribute.
841 * This is done to ensure there is a 1:1 mapping between the attribute value
842 * length and the number of blocks needed to store the attribute. This makes the
843 * verification of a buffer a little more complex, but greatly simplifies the
844 * allocation, reading and writing of these attributes as we don't have to guess
845 * the number of blocks needed to store the attribute data.
846 */
847 #define XFS_ATTR3_RMT_MAGIC 0x5841524d /* XARM */
848
849 struct xfs_attr3_rmt_hdr {
850 __be32 rm_magic;
851 __be32 rm_offset;
852 __be32 rm_bytes;
853 __be32 rm_crc;
854 uuid_t rm_uuid;
855 __be64 rm_owner;
856 __be64 rm_blkno;
857 __be64 rm_lsn;
858 };
859
860 #define XFS_ATTR3_RMT_CRC_OFF offsetof(struct xfs_attr3_rmt_hdr, rm_crc)
861
862 #define XFS_ATTR3_RMT_BUF_SPACE(mp, bufsize) \
863 ((bufsize) - (xfs_sb_version_hascrc(&(mp)->m_sb) ? \
864 sizeof(struct xfs_attr3_rmt_hdr) : 0))
865
866 /* Number of bytes in a directory block. */
xfs_dir2_dirblock_bytes(struct xfs_sb * sbp)867 static inline unsigned int xfs_dir2_dirblock_bytes(struct xfs_sb *sbp)
868 {
869 return 1 << (sbp->sb_blocklog + sbp->sb_dirblklog);
870 }
871
872 #endif /* __XFS_DA_FORMAT_H__ */
873