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[PATCH] pass MAY_OPEN to vfs_permission() explicitly
[deliverable/linux.git] / fs / xfs / xfs_dir2_data.c
1 /*
2 * Copyright (c) 2000-2002,2005 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 #include "xfs.h"
19 #include "xfs_fs.h"
20 #include "xfs_types.h"
21 #include "xfs_log.h"
22 #include "xfs_inum.h"
23 #include "xfs_trans.h"
24 #include "xfs_sb.h"
25 #include "xfs_ag.h"
26 #include "xfs_dir2.h"
27 #include "xfs_dmapi.h"
28 #include "xfs_mount.h"
29 #include "xfs_da_btree.h"
30 #include "xfs_bmap_btree.h"
31 #include "xfs_dir2_sf.h"
32 #include "xfs_attr_sf.h"
33 #include "xfs_dinode.h"
34 #include "xfs_inode.h"
35 #include "xfs_dir2_data.h"
36 #include "xfs_dir2_leaf.h"
37 #include "xfs_dir2_block.h"
38 #include "xfs_error.h"
39
40 #ifdef DEBUG
41 /*
42 * Check the consistency of the data block.
43 * The input can also be a block-format directory.
44 * Pop an assert if we find anything bad.
45 */
46 void
47 xfs_dir2_data_check(
48 xfs_inode_t *dp, /* incore inode pointer */
49 xfs_dabuf_t *bp) /* data block's buffer */
50 {
51 xfs_dir2_dataptr_t addr; /* addr for leaf lookup */
52 xfs_dir2_data_free_t *bf; /* bestfree table */
53 xfs_dir2_block_tail_t *btp=NULL; /* block tail */
54 int count; /* count of entries found */
55 xfs_dir2_data_t *d; /* data block pointer */
56 xfs_dir2_data_entry_t *dep; /* data entry */
57 xfs_dir2_data_free_t *dfp; /* bestfree entry */
58 xfs_dir2_data_unused_t *dup; /* unused entry */
59 char *endp; /* end of useful data */
60 int freeseen; /* mask of bestfrees seen */
61 xfs_dahash_t hash; /* hash of current name */
62 int i; /* leaf index */
63 int lastfree; /* last entry was unused */
64 xfs_dir2_leaf_entry_t *lep=NULL; /* block leaf entries */
65 xfs_mount_t *mp; /* filesystem mount point */
66 char *p; /* current data position */
67 int stale; /* count of stale leaves */
68
69 mp = dp->i_mount;
70 d = bp->data;
71 ASSERT(be32_to_cpu(d->hdr.magic) == XFS_DIR2_DATA_MAGIC ||
72 be32_to_cpu(d->hdr.magic) == XFS_DIR2_BLOCK_MAGIC);
73 bf = d->hdr.bestfree;
74 p = (char *)d->u;
75 if (be32_to_cpu(d->hdr.magic) == XFS_DIR2_BLOCK_MAGIC) {
76 btp = xfs_dir2_block_tail_p(mp, (xfs_dir2_block_t *)d);
77 lep = xfs_dir2_block_leaf_p(btp);
78 endp = (char *)lep;
79 } else
80 endp = (char *)d + mp->m_dirblksize;
81 count = lastfree = freeseen = 0;
82 /*
83 * Account for zero bestfree entries.
84 */
85 if (!bf[0].length) {
86 ASSERT(!bf[0].offset);
87 freeseen |= 1 << 0;
88 }
89 if (!bf[1].length) {
90 ASSERT(!bf[1].offset);
91 freeseen |= 1 << 1;
92 }
93 if (!bf[2].length) {
94 ASSERT(!bf[2].offset);
95 freeseen |= 1 << 2;
96 }
97 ASSERT(be16_to_cpu(bf[0].length) >= be16_to_cpu(bf[1].length));
98 ASSERT(be16_to_cpu(bf[1].length) >= be16_to_cpu(bf[2].length));
99 /*
100 * Loop over the data/unused entries.
101 */
102 while (p < endp) {
103 dup = (xfs_dir2_data_unused_t *)p;
104 /*
105 * If it's unused, look for the space in the bestfree table.
106 * If we find it, account for that, else make sure it
107 * doesn't need to be there.
108 */
109 if (be16_to_cpu(dup->freetag) == XFS_DIR2_DATA_FREE_TAG) {
110 ASSERT(lastfree == 0);
111 ASSERT(be16_to_cpu(*xfs_dir2_data_unused_tag_p(dup)) ==
112 (char *)dup - (char *)d);
113 dfp = xfs_dir2_data_freefind(d, dup);
114 if (dfp) {
115 i = (int)(dfp - bf);
116 ASSERT((freeseen & (1 << i)) == 0);
117 freeseen |= 1 << i;
118 } else {
119 ASSERT(be16_to_cpu(dup->length) <=
120 be16_to_cpu(bf[2].length));
121 }
122 p += be16_to_cpu(dup->length);
123 lastfree = 1;
124 continue;
125 }
126 /*
127 * It's a real entry. Validate the fields.
128 * If this is a block directory then make sure it's
129 * in the leaf section of the block.
130 * The linear search is crude but this is DEBUG code.
131 */
132 dep = (xfs_dir2_data_entry_t *)p;
133 ASSERT(dep->namelen != 0);
134 ASSERT(xfs_dir_ino_validate(mp, be64_to_cpu(dep->inumber)) == 0);
135 ASSERT(be16_to_cpu(*xfs_dir2_data_entry_tag_p(dep)) ==
136 (char *)dep - (char *)d);
137 count++;
138 lastfree = 0;
139 if (be32_to_cpu(d->hdr.magic) == XFS_DIR2_BLOCK_MAGIC) {
140 addr = xfs_dir2_db_off_to_dataptr(mp, mp->m_dirdatablk,
141 (xfs_dir2_data_aoff_t)
142 ((char *)dep - (char *)d));
143 hash = xfs_da_hashname((char *)dep->name, dep->namelen);
144 for (i = 0; i < be32_to_cpu(btp->count); i++) {
145 if (be32_to_cpu(lep[i].address) == addr &&
146 be32_to_cpu(lep[i].hashval) == hash)
147 break;
148 }
149 ASSERT(i < be32_to_cpu(btp->count));
150 }
151 p += xfs_dir2_data_entsize(dep->namelen);
152 }
153 /*
154 * Need to have seen all the entries and all the bestfree slots.
155 */
156 ASSERT(freeseen == 7);
157 if (be32_to_cpu(d->hdr.magic) == XFS_DIR2_BLOCK_MAGIC) {
158 for (i = stale = 0; i < be32_to_cpu(btp->count); i++) {
159 if (be32_to_cpu(lep[i].address) == XFS_DIR2_NULL_DATAPTR)
160 stale++;
161 if (i > 0)
162 ASSERT(be32_to_cpu(lep[i].hashval) >= be32_to_cpu(lep[i - 1].hashval));
163 }
164 ASSERT(count == be32_to_cpu(btp->count) - be32_to_cpu(btp->stale));
165 ASSERT(stale == be32_to_cpu(btp->stale));
166 }
167 }
168 #endif
169
170 /*
171 * Given a data block and an unused entry from that block,
172 * return the bestfree entry if any that corresponds to it.
173 */
174 xfs_dir2_data_free_t *
175 xfs_dir2_data_freefind(
176 xfs_dir2_data_t *d, /* data block */
177 xfs_dir2_data_unused_t *dup) /* data unused entry */
178 {
179 xfs_dir2_data_free_t *dfp; /* bestfree entry */
180 xfs_dir2_data_aoff_t off; /* offset value needed */
181 #if defined(DEBUG) && defined(__KERNEL__)
182 int matched; /* matched the value */
183 int seenzero; /* saw a 0 bestfree entry */
184 #endif
185
186 off = (xfs_dir2_data_aoff_t)((char *)dup - (char *)d);
187 #if defined(DEBUG) && defined(__KERNEL__)
188 /*
189 * Validate some consistency in the bestfree table.
190 * Check order, non-overlapping entries, and if we find the
191 * one we're looking for it has to be exact.
192 */
193 ASSERT(be32_to_cpu(d->hdr.magic) == XFS_DIR2_DATA_MAGIC ||
194 be32_to_cpu(d->hdr.magic) == XFS_DIR2_BLOCK_MAGIC);
195 for (dfp = &d->hdr.bestfree[0], seenzero = matched = 0;
196 dfp < &d->hdr.bestfree[XFS_DIR2_DATA_FD_COUNT];
197 dfp++) {
198 if (!dfp->offset) {
199 ASSERT(!dfp->length);
200 seenzero = 1;
201 continue;
202 }
203 ASSERT(seenzero == 0);
204 if (be16_to_cpu(dfp->offset) == off) {
205 matched = 1;
206 ASSERT(dfp->length == dup->length);
207 } else if (off < be16_to_cpu(dfp->offset))
208 ASSERT(off + be16_to_cpu(dup->length) <= be16_to_cpu(dfp->offset));
209 else
210 ASSERT(be16_to_cpu(dfp->offset) + be16_to_cpu(dfp->length) <= off);
211 ASSERT(matched || be16_to_cpu(dfp->length) >= be16_to_cpu(dup->length));
212 if (dfp > &d->hdr.bestfree[0])
213 ASSERT(be16_to_cpu(dfp[-1].length) >= be16_to_cpu(dfp[0].length));
214 }
215 #endif
216 /*
217 * If this is smaller than the smallest bestfree entry,
218 * it can't be there since they're sorted.
219 */
220 if (be16_to_cpu(dup->length) <
221 be16_to_cpu(d->hdr.bestfree[XFS_DIR2_DATA_FD_COUNT - 1].length))
222 return NULL;
223 /*
224 * Look at the three bestfree entries for our guy.
225 */
226 for (dfp = &d->hdr.bestfree[0];
227 dfp < &d->hdr.bestfree[XFS_DIR2_DATA_FD_COUNT];
228 dfp++) {
229 if (!dfp->offset)
230 return NULL;
231 if (be16_to_cpu(dfp->offset) == off)
232 return dfp;
233 }
234 /*
235 * Didn't find it. This only happens if there are duplicate lengths.
236 */
237 return NULL;
238 }
239
240 /*
241 * Insert an unused-space entry into the bestfree table.
242 */
243 xfs_dir2_data_free_t * /* entry inserted */
244 xfs_dir2_data_freeinsert(
245 xfs_dir2_data_t *d, /* data block pointer */
246 xfs_dir2_data_unused_t *dup, /* unused space */
247 int *loghead) /* log the data header (out) */
248 {
249 xfs_dir2_data_free_t *dfp; /* bestfree table pointer */
250 xfs_dir2_data_free_t new; /* new bestfree entry */
251
252 #ifdef __KERNEL__
253 ASSERT(be32_to_cpu(d->hdr.magic) == XFS_DIR2_DATA_MAGIC ||
254 be32_to_cpu(d->hdr.magic) == XFS_DIR2_BLOCK_MAGIC);
255 #endif
256 dfp = d->hdr.bestfree;
257 new.length = dup->length;
258 new.offset = cpu_to_be16((char *)dup - (char *)d);
259 /*
260 * Insert at position 0, 1, or 2; or not at all.
261 */
262 if (be16_to_cpu(new.length) > be16_to_cpu(dfp[0].length)) {
263 dfp[2] = dfp[1];
264 dfp[1] = dfp[0];
265 dfp[0] = new;
266 *loghead = 1;
267 return &dfp[0];
268 }
269 if (be16_to_cpu(new.length) > be16_to_cpu(dfp[1].length)) {
270 dfp[2] = dfp[1];
271 dfp[1] = new;
272 *loghead = 1;
273 return &dfp[1];
274 }
275 if (be16_to_cpu(new.length) > be16_to_cpu(dfp[2].length)) {
276 dfp[2] = new;
277 *loghead = 1;
278 return &dfp[2];
279 }
280 return NULL;
281 }
282
283 /*
284 * Remove a bestfree entry from the table.
285 */
286 STATIC void
287 xfs_dir2_data_freeremove(
288 xfs_dir2_data_t *d, /* data block pointer */
289 xfs_dir2_data_free_t *dfp, /* bestfree entry pointer */
290 int *loghead) /* out: log data header */
291 {
292 #ifdef __KERNEL__
293 ASSERT(be32_to_cpu(d->hdr.magic) == XFS_DIR2_DATA_MAGIC ||
294 be32_to_cpu(d->hdr.magic) == XFS_DIR2_BLOCK_MAGIC);
295 #endif
296 /*
297 * It's the first entry, slide the next 2 up.
298 */
299 if (dfp == &d->hdr.bestfree[0]) {
300 d->hdr.bestfree[0] = d->hdr.bestfree[1];
301 d->hdr.bestfree[1] = d->hdr.bestfree[2];
302 }
303 /*
304 * It's the second entry, slide the 3rd entry up.
305 */
306 else if (dfp == &d->hdr.bestfree[1])
307 d->hdr.bestfree[1] = d->hdr.bestfree[2];
308 /*
309 * Must be the last entry.
310 */
311 else
312 ASSERT(dfp == &d->hdr.bestfree[2]);
313 /*
314 * Clear the 3rd entry, must be zero now.
315 */
316 d->hdr.bestfree[2].length = 0;
317 d->hdr.bestfree[2].offset = 0;
318 *loghead = 1;
319 }
320
321 /*
322 * Given a data block, reconstruct its bestfree map.
323 */
324 void
325 xfs_dir2_data_freescan(
326 xfs_mount_t *mp, /* filesystem mount point */
327 xfs_dir2_data_t *d, /* data block pointer */
328 int *loghead) /* out: log data header */
329 {
330 xfs_dir2_block_tail_t *btp; /* block tail */
331 xfs_dir2_data_entry_t *dep; /* active data entry */
332 xfs_dir2_data_unused_t *dup; /* unused data entry */
333 char *endp; /* end of block's data */
334 char *p; /* current entry pointer */
335
336 #ifdef __KERNEL__
337 ASSERT(be32_to_cpu(d->hdr.magic) == XFS_DIR2_DATA_MAGIC ||
338 be32_to_cpu(d->hdr.magic) == XFS_DIR2_BLOCK_MAGIC);
339 #endif
340 /*
341 * Start by clearing the table.
342 */
343 memset(d->hdr.bestfree, 0, sizeof(d->hdr.bestfree));
344 *loghead = 1;
345 /*
346 * Set up pointers.
347 */
348 p = (char *)d->u;
349 if (be32_to_cpu(d->hdr.magic) == XFS_DIR2_BLOCK_MAGIC) {
350 btp = xfs_dir2_block_tail_p(mp, (xfs_dir2_block_t *)d);
351 endp = (char *)xfs_dir2_block_leaf_p(btp);
352 } else
353 endp = (char *)d + mp->m_dirblksize;
354 /*
355 * Loop over the block's entries.
356 */
357 while (p < endp) {
358 dup = (xfs_dir2_data_unused_t *)p;
359 /*
360 * If it's a free entry, insert it.
361 */
362 if (be16_to_cpu(dup->freetag) == XFS_DIR2_DATA_FREE_TAG) {
363 ASSERT((char *)dup - (char *)d ==
364 be16_to_cpu(*xfs_dir2_data_unused_tag_p(dup)));
365 xfs_dir2_data_freeinsert(d, dup, loghead);
366 p += be16_to_cpu(dup->length);
367 }
368 /*
369 * For active entries, check their tags and skip them.
370 */
371 else {
372 dep = (xfs_dir2_data_entry_t *)p;
373 ASSERT((char *)dep - (char *)d ==
374 be16_to_cpu(*xfs_dir2_data_entry_tag_p(dep)));
375 p += xfs_dir2_data_entsize(dep->namelen);
376 }
377 }
378 }
379
380 /*
381 * Initialize a data block at the given block number in the directory.
382 * Give back the buffer for the created block.
383 */
384 int /* error */
385 xfs_dir2_data_init(
386 xfs_da_args_t *args, /* directory operation args */
387 xfs_dir2_db_t blkno, /* logical dir block number */
388 xfs_dabuf_t **bpp) /* output block buffer */
389 {
390 xfs_dabuf_t *bp; /* block buffer */
391 xfs_dir2_data_t *d; /* pointer to block */
392 xfs_inode_t *dp; /* incore directory inode */
393 xfs_dir2_data_unused_t *dup; /* unused entry pointer */
394 int error; /* error return value */
395 int i; /* bestfree index */
396 xfs_mount_t *mp; /* filesystem mount point */
397 xfs_trans_t *tp; /* transaction pointer */
398 int t; /* temp */
399
400 dp = args->dp;
401 mp = dp->i_mount;
402 tp = args->trans;
403 /*
404 * Get the buffer set up for the block.
405 */
406 error = xfs_da_get_buf(tp, dp, xfs_dir2_db_to_da(mp, blkno), -1, &bp,
407 XFS_DATA_FORK);
408 if (error) {
409 return error;
410 }
411 ASSERT(bp != NULL);
412 /*
413 * Initialize the header.
414 */
415 d = bp->data;
416 d->hdr.magic = cpu_to_be32(XFS_DIR2_DATA_MAGIC);
417 d->hdr.bestfree[0].offset = cpu_to_be16(sizeof(d->hdr));
418 for (i = 1; i < XFS_DIR2_DATA_FD_COUNT; i++) {
419 d->hdr.bestfree[i].length = 0;
420 d->hdr.bestfree[i].offset = 0;
421 }
422 /*
423 * Set up an unused entry for the block's body.
424 */
425 dup = &d->u[0].unused;
426 dup->freetag = cpu_to_be16(XFS_DIR2_DATA_FREE_TAG);
427
428 t=mp->m_dirblksize - (uint)sizeof(d->hdr);
429 d->hdr.bestfree[0].length = cpu_to_be16(t);
430 dup->length = cpu_to_be16(t);
431 *xfs_dir2_data_unused_tag_p(dup) = cpu_to_be16((char *)dup - (char *)d);
432 /*
433 * Log it and return it.
434 */
435 xfs_dir2_data_log_header(tp, bp);
436 xfs_dir2_data_log_unused(tp, bp, dup);
437 *bpp = bp;
438 return 0;
439 }
440
441 /*
442 * Log an active data entry from the block.
443 */
444 void
445 xfs_dir2_data_log_entry(
446 xfs_trans_t *tp, /* transaction pointer */
447 xfs_dabuf_t *bp, /* block buffer */
448 xfs_dir2_data_entry_t *dep) /* data entry pointer */
449 {
450 xfs_dir2_data_t *d; /* data block pointer */
451
452 d = bp->data;
453 ASSERT(be32_to_cpu(d->hdr.magic) == XFS_DIR2_DATA_MAGIC ||
454 be32_to_cpu(d->hdr.magic) == XFS_DIR2_BLOCK_MAGIC);
455 xfs_da_log_buf(tp, bp, (uint)((char *)dep - (char *)d),
456 (uint)((char *)(xfs_dir2_data_entry_tag_p(dep) + 1) -
457 (char *)d - 1));
458 }
459
460 /*
461 * Log a data block header.
462 */
463 void
464 xfs_dir2_data_log_header(
465 xfs_trans_t *tp, /* transaction pointer */
466 xfs_dabuf_t *bp) /* block buffer */
467 {
468 xfs_dir2_data_t *d; /* data block pointer */
469
470 d = bp->data;
471 ASSERT(be32_to_cpu(d->hdr.magic) == XFS_DIR2_DATA_MAGIC ||
472 be32_to_cpu(d->hdr.magic) == XFS_DIR2_BLOCK_MAGIC);
473 xfs_da_log_buf(tp, bp, (uint)((char *)&d->hdr - (char *)d),
474 (uint)(sizeof(d->hdr) - 1));
475 }
476
477 /*
478 * Log a data unused entry.
479 */
480 void
481 xfs_dir2_data_log_unused(
482 xfs_trans_t *tp, /* transaction pointer */
483 xfs_dabuf_t *bp, /* block buffer */
484 xfs_dir2_data_unused_t *dup) /* data unused pointer */
485 {
486 xfs_dir2_data_t *d; /* data block pointer */
487
488 d = bp->data;
489 ASSERT(be32_to_cpu(d->hdr.magic) == XFS_DIR2_DATA_MAGIC ||
490 be32_to_cpu(d->hdr.magic) == XFS_DIR2_BLOCK_MAGIC);
491 /*
492 * Log the first part of the unused entry.
493 */
494 xfs_da_log_buf(tp, bp, (uint)((char *)dup - (char *)d),
495 (uint)((char *)&dup->length + sizeof(dup->length) -
496 1 - (char *)d));
497 /*
498 * Log the end (tag) of the unused entry.
499 */
500 xfs_da_log_buf(tp, bp,
501 (uint)((char *)xfs_dir2_data_unused_tag_p(dup) - (char *)d),
502 (uint)((char *)xfs_dir2_data_unused_tag_p(dup) - (char *)d +
503 sizeof(xfs_dir2_data_off_t) - 1));
504 }
505
506 /*
507 * Make a byte range in the data block unused.
508 * Its current contents are unimportant.
509 */
510 void
511 xfs_dir2_data_make_free(
512 xfs_trans_t *tp, /* transaction pointer */
513 xfs_dabuf_t *bp, /* block buffer */
514 xfs_dir2_data_aoff_t offset, /* starting byte offset */
515 xfs_dir2_data_aoff_t len, /* length in bytes */
516 int *needlogp, /* out: log header */
517 int *needscanp) /* out: regen bestfree */
518 {
519 xfs_dir2_data_t *d; /* data block pointer */
520 xfs_dir2_data_free_t *dfp; /* bestfree pointer */
521 char *endptr; /* end of data area */
522 xfs_mount_t *mp; /* filesystem mount point */
523 int needscan; /* need to regen bestfree */
524 xfs_dir2_data_unused_t *newdup; /* new unused entry */
525 xfs_dir2_data_unused_t *postdup; /* unused entry after us */
526 xfs_dir2_data_unused_t *prevdup; /* unused entry before us */
527
528 mp = tp->t_mountp;
529 d = bp->data;
530 /*
531 * Figure out where the end of the data area is.
532 */
533 if (be32_to_cpu(d->hdr.magic) == XFS_DIR2_DATA_MAGIC)
534 endptr = (char *)d + mp->m_dirblksize;
535 else {
536 xfs_dir2_block_tail_t *btp; /* block tail */
537
538 ASSERT(be32_to_cpu(d->hdr.magic) == XFS_DIR2_BLOCK_MAGIC);
539 btp = xfs_dir2_block_tail_p(mp, (xfs_dir2_block_t *)d);
540 endptr = (char *)xfs_dir2_block_leaf_p(btp);
541 }
542 /*
543 * If this isn't the start of the block, then back up to
544 * the previous entry and see if it's free.
545 */
546 if (offset > sizeof(d->hdr)) {
547 __be16 *tagp; /* tag just before us */
548
549 tagp = (__be16 *)((char *)d + offset) - 1;
550 prevdup = (xfs_dir2_data_unused_t *)((char *)d + be16_to_cpu(*tagp));
551 if (be16_to_cpu(prevdup->freetag) != XFS_DIR2_DATA_FREE_TAG)
552 prevdup = NULL;
553 } else
554 prevdup = NULL;
555 /*
556 * If this isn't the end of the block, see if the entry after
557 * us is free.
558 */
559 if ((char *)d + offset + len < endptr) {
560 postdup =
561 (xfs_dir2_data_unused_t *)((char *)d + offset + len);
562 if (be16_to_cpu(postdup->freetag) != XFS_DIR2_DATA_FREE_TAG)
563 postdup = NULL;
564 } else
565 postdup = NULL;
566 ASSERT(*needscanp == 0);
567 needscan = 0;
568 /*
569 * Previous and following entries are both free,
570 * merge everything into a single free entry.
571 */
572 if (prevdup && postdup) {
573 xfs_dir2_data_free_t *dfp2; /* another bestfree pointer */
574
575 /*
576 * See if prevdup and/or postdup are in bestfree table.
577 */
578 dfp = xfs_dir2_data_freefind(d, prevdup);
579 dfp2 = xfs_dir2_data_freefind(d, postdup);
580 /*
581 * We need a rescan unless there are exactly 2 free entries
582 * namely our two. Then we know what's happening, otherwise
583 * since the third bestfree is there, there might be more
584 * entries.
585 */
586 needscan = (d->hdr.bestfree[2].length != 0);
587 /*
588 * Fix up the new big freespace.
589 */
590 be16_add_cpu(&prevdup->length, len + be16_to_cpu(postdup->length));
591 *xfs_dir2_data_unused_tag_p(prevdup) =
592 cpu_to_be16((char *)prevdup - (char *)d);
593 xfs_dir2_data_log_unused(tp, bp, prevdup);
594 if (!needscan) {
595 /*
596 * Has to be the case that entries 0 and 1 are
597 * dfp and dfp2 (don't know which is which), and
598 * entry 2 is empty.
599 * Remove entry 1 first then entry 0.
600 */
601 ASSERT(dfp && dfp2);
602 if (dfp == &d->hdr.bestfree[1]) {
603 dfp = &d->hdr.bestfree[0];
604 ASSERT(dfp2 == dfp);
605 dfp2 = &d->hdr.bestfree[1];
606 }
607 xfs_dir2_data_freeremove(d, dfp2, needlogp);
608 xfs_dir2_data_freeremove(d, dfp, needlogp);
609 /*
610 * Now insert the new entry.
611 */
612 dfp = xfs_dir2_data_freeinsert(d, prevdup, needlogp);
613 ASSERT(dfp == &d->hdr.bestfree[0]);
614 ASSERT(dfp->length == prevdup->length);
615 ASSERT(!dfp[1].length);
616 ASSERT(!dfp[2].length);
617 }
618 }
619 /*
620 * The entry before us is free, merge with it.
621 */
622 else if (prevdup) {
623 dfp = xfs_dir2_data_freefind(d, prevdup);
624 be16_add_cpu(&prevdup->length, len);
625 *xfs_dir2_data_unused_tag_p(prevdup) =
626 cpu_to_be16((char *)prevdup - (char *)d);
627 xfs_dir2_data_log_unused(tp, bp, prevdup);
628 /*
629 * If the previous entry was in the table, the new entry
630 * is longer, so it will be in the table too. Remove
631 * the old one and add the new one.
632 */
633 if (dfp) {
634 xfs_dir2_data_freeremove(d, dfp, needlogp);
635 (void)xfs_dir2_data_freeinsert(d, prevdup, needlogp);
636 }
637 /*
638 * Otherwise we need a scan if the new entry is big enough.
639 */
640 else {
641 needscan = be16_to_cpu(prevdup->length) >
642 be16_to_cpu(d->hdr.bestfree[2].length);
643 }
644 }
645 /*
646 * The following entry is free, merge with it.
647 */
648 else if (postdup) {
649 dfp = xfs_dir2_data_freefind(d, postdup);
650 newdup = (xfs_dir2_data_unused_t *)((char *)d + offset);
651 newdup->freetag = cpu_to_be16(XFS_DIR2_DATA_FREE_TAG);
652 newdup->length = cpu_to_be16(len + be16_to_cpu(postdup->length));
653 *xfs_dir2_data_unused_tag_p(newdup) =
654 cpu_to_be16((char *)newdup - (char *)d);
655 xfs_dir2_data_log_unused(tp, bp, newdup);
656 /*
657 * If the following entry was in the table, the new entry
658 * is longer, so it will be in the table too. Remove
659 * the old one and add the new one.
660 */
661 if (dfp) {
662 xfs_dir2_data_freeremove(d, dfp, needlogp);
663 (void)xfs_dir2_data_freeinsert(d, newdup, needlogp);
664 }
665 /*
666 * Otherwise we need a scan if the new entry is big enough.
667 */
668 else {
669 needscan = be16_to_cpu(newdup->length) >
670 be16_to_cpu(d->hdr.bestfree[2].length);
671 }
672 }
673 /*
674 * Neither neighbor is free. Make a new entry.
675 */
676 else {
677 newdup = (xfs_dir2_data_unused_t *)((char *)d + offset);
678 newdup->freetag = cpu_to_be16(XFS_DIR2_DATA_FREE_TAG);
679 newdup->length = cpu_to_be16(len);
680 *xfs_dir2_data_unused_tag_p(newdup) =
681 cpu_to_be16((char *)newdup - (char *)d);
682 xfs_dir2_data_log_unused(tp, bp, newdup);
683 (void)xfs_dir2_data_freeinsert(d, newdup, needlogp);
684 }
685 *needscanp = needscan;
686 }
687
688 /*
689 * Take a byte range out of an existing unused space and make it un-free.
690 */
691 void
692 xfs_dir2_data_use_free(
693 xfs_trans_t *tp, /* transaction pointer */
694 xfs_dabuf_t *bp, /* data block buffer */
695 xfs_dir2_data_unused_t *dup, /* unused entry */
696 xfs_dir2_data_aoff_t offset, /* starting offset to use */
697 xfs_dir2_data_aoff_t len, /* length to use */
698 int *needlogp, /* out: need to log header */
699 int *needscanp) /* out: need regen bestfree */
700 {
701 xfs_dir2_data_t *d; /* data block */
702 xfs_dir2_data_free_t *dfp; /* bestfree pointer */
703 int matchback; /* matches end of freespace */
704 int matchfront; /* matches start of freespace */
705 int needscan; /* need to regen bestfree */
706 xfs_dir2_data_unused_t *newdup; /* new unused entry */
707 xfs_dir2_data_unused_t *newdup2; /* another new unused entry */
708 int oldlen; /* old unused entry's length */
709
710 d = bp->data;
711 ASSERT(be32_to_cpu(d->hdr.magic) == XFS_DIR2_DATA_MAGIC ||
712 be32_to_cpu(d->hdr.magic) == XFS_DIR2_BLOCK_MAGIC);
713 ASSERT(be16_to_cpu(dup->freetag) == XFS_DIR2_DATA_FREE_TAG);
714 ASSERT(offset >= (char *)dup - (char *)d);
715 ASSERT(offset + len <= (char *)dup + be16_to_cpu(dup->length) - (char *)d);
716 ASSERT((char *)dup - (char *)d == be16_to_cpu(*xfs_dir2_data_unused_tag_p(dup)));
717 /*
718 * Look up the entry in the bestfree table.
719 */
720 dfp = xfs_dir2_data_freefind(d, dup);
721 oldlen = be16_to_cpu(dup->length);
722 ASSERT(dfp || oldlen <= be16_to_cpu(d->hdr.bestfree[2].length));
723 /*
724 * Check for alignment with front and back of the entry.
725 */
726 matchfront = (char *)dup - (char *)d == offset;
727 matchback = (char *)dup + oldlen - (char *)d == offset + len;
728 ASSERT(*needscanp == 0);
729 needscan = 0;
730 /*
731 * If we matched it exactly we just need to get rid of it from
732 * the bestfree table.
733 */
734 if (matchfront && matchback) {
735 if (dfp) {
736 needscan = (d->hdr.bestfree[2].offset != 0);
737 if (!needscan)
738 xfs_dir2_data_freeremove(d, dfp, needlogp);
739 }
740 }
741 /*
742 * We match the first part of the entry.
743 * Make a new entry with the remaining freespace.
744 */
745 else if (matchfront) {
746 newdup = (xfs_dir2_data_unused_t *)((char *)d + offset + len);
747 newdup->freetag = cpu_to_be16(XFS_DIR2_DATA_FREE_TAG);
748 newdup->length = cpu_to_be16(oldlen - len);
749 *xfs_dir2_data_unused_tag_p(newdup) =
750 cpu_to_be16((char *)newdup - (char *)d);
751 xfs_dir2_data_log_unused(tp, bp, newdup);
752 /*
753 * If it was in the table, remove it and add the new one.
754 */
755 if (dfp) {
756 xfs_dir2_data_freeremove(d, dfp, needlogp);
757 dfp = xfs_dir2_data_freeinsert(d, newdup, needlogp);
758 ASSERT(dfp != NULL);
759 ASSERT(dfp->length == newdup->length);
760 ASSERT(be16_to_cpu(dfp->offset) == (char *)newdup - (char *)d);
761 /*
762 * If we got inserted at the last slot,
763 * that means we don't know if there was a better
764 * choice for the last slot, or not. Rescan.
765 */
766 needscan = dfp == &d->hdr.bestfree[2];
767 }
768 }
769 /*
770 * We match the last part of the entry.
771 * Trim the allocated space off the tail of the entry.
772 */
773 else if (matchback) {
774 newdup = dup;
775 newdup->length = cpu_to_be16(((char *)d + offset) - (char *)newdup);
776 *xfs_dir2_data_unused_tag_p(newdup) =
777 cpu_to_be16((char *)newdup - (char *)d);
778 xfs_dir2_data_log_unused(tp, bp, newdup);
779 /*
780 * If it was in the table, remove it and add the new one.
781 */
782 if (dfp) {
783 xfs_dir2_data_freeremove(d, dfp, needlogp);
784 dfp = xfs_dir2_data_freeinsert(d, newdup, needlogp);
785 ASSERT(dfp != NULL);
786 ASSERT(dfp->length == newdup->length);
787 ASSERT(be16_to_cpu(dfp->offset) == (char *)newdup - (char *)d);
788 /*
789 * If we got inserted at the last slot,
790 * that means we don't know if there was a better
791 * choice for the last slot, or not. Rescan.
792 */
793 needscan = dfp == &d->hdr.bestfree[2];
794 }
795 }
796 /*
797 * Poking out the middle of an entry.
798 * Make two new entries.
799 */
800 else {
801 newdup = dup;
802 newdup->length = cpu_to_be16(((char *)d + offset) - (char *)newdup);
803 *xfs_dir2_data_unused_tag_p(newdup) =
804 cpu_to_be16((char *)newdup - (char *)d);
805 xfs_dir2_data_log_unused(tp, bp, newdup);
806 newdup2 = (xfs_dir2_data_unused_t *)((char *)d + offset + len);
807 newdup2->freetag = cpu_to_be16(XFS_DIR2_DATA_FREE_TAG);
808 newdup2->length = cpu_to_be16(oldlen - len - be16_to_cpu(newdup->length));
809 *xfs_dir2_data_unused_tag_p(newdup2) =
810 cpu_to_be16((char *)newdup2 - (char *)d);
811 xfs_dir2_data_log_unused(tp, bp, newdup2);
812 /*
813 * If the old entry was in the table, we need to scan
814 * if the 3rd entry was valid, since these entries
815 * are smaller than the old one.
816 * If we don't need to scan that means there were 1 or 2
817 * entries in the table, and removing the old and adding
818 * the 2 new will work.
819 */
820 if (dfp) {
821 needscan = (d->hdr.bestfree[2].length != 0);
822 if (!needscan) {
823 xfs_dir2_data_freeremove(d, dfp, needlogp);
824 (void)xfs_dir2_data_freeinsert(d, newdup,
825 needlogp);
826 (void)xfs_dir2_data_freeinsert(d, newdup2,
827 needlogp);
828 }
829 }
830 }
831 *needscanp = needscan;
832 }
Linux kernel - Deliverables
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