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MIPS: Yosemite, Emma: Fix off-by-two in arcs_cmdline buffer size check
[linux-2.6/linux-mips.git] / fs / xfs / xfs_dir2_data.c
blob5bbe2a8a023fdf91a90fba711375d5c2b747c2ce
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_mount.h"
27 #include "xfs_da_btree.h"
28 #include "xfs_bmap_btree.h"
29 #include "xfs_dinode.h"
30 #include "xfs_inode.h"
31 #include "xfs_dir2_format.h"
32 #include "xfs_dir2_priv.h"
33 #include "xfs_error.h"
34
35 STATIC xfs_dir2_data_free_t *
36 xfs_dir2_data_freefind(xfs_dir2_data_hdr_t *hdr, xfs_dir2_data_unused_t *dup);
37
38 #ifdef DEBUG
39 /*
40 * Check the consistency of the data block.
41 * The input can also be a block-format directory.
42 * Pop an assert if we find anything bad.
43 */
44 void
45 xfs_dir2_data_check(
46 xfs_inode_t *dp, /* incore inode pointer */
47 xfs_dabuf_t *bp) /* data block's buffer */
48 {
49 xfs_dir2_dataptr_t addr; /* addr for leaf lookup */
50 xfs_dir2_data_free_t *bf; /* bestfree table */
51 xfs_dir2_block_tail_t *btp=NULL; /* block tail */
52 int count; /* count of entries found */
53 xfs_dir2_data_hdr_t *hdr; /* data block header */
54 xfs_dir2_data_entry_t *dep; /* data entry */
55 xfs_dir2_data_free_t *dfp; /* bestfree entry */
56 xfs_dir2_data_unused_t *dup; /* unused entry */
57 char *endp; /* end of useful data */
58 int freeseen; /* mask of bestfrees seen */
59 xfs_dahash_t hash; /* hash of current name */
60 int i; /* leaf index */
61 int lastfree; /* last entry was unused */
62 xfs_dir2_leaf_entry_t *lep=NULL; /* block leaf entries */
63 xfs_mount_t *mp; /* filesystem mount point */
64 char *p; /* current data position */
65 int stale; /* count of stale leaves */
66 struct xfs_name name;
67
68 mp = dp->i_mount;
69 hdr = bp->data;
70 bf = hdr->bestfree;
71 p = (char *)(hdr + 1);
72
73 if (hdr->magic == cpu_to_be32(XFS_DIR2_BLOCK_MAGIC)) {
74 btp = xfs_dir2_block_tail_p(mp, hdr);
75 lep = xfs_dir2_block_leaf_p(btp);
76 endp = (char *)lep;
77 } else {
78 ASSERT(hdr->magic == cpu_to_be32(XFS_DIR2_DATA_MAGIC));
79 endp = (char *)hdr + mp->m_dirblksize;
80 }
81
82 count = lastfree = freeseen = 0;
83 /*
84 * Account for zero bestfree entries.
85 */
86 if (!bf[0].length) {
87 ASSERT(!bf[0].offset);
88 freeseen |= 1 << 0;
89 }
90 if (!bf[1].length) {
91 ASSERT(!bf[1].offset);
92 freeseen |= 1 << 1;
93 }
94 if (!bf[2].length) {
95 ASSERT(!bf[2].offset);
96 freeseen |= 1 << 2;
97 }
98 ASSERT(be16_to_cpu(bf[0].length) >= be16_to_cpu(bf[1].length));
99 ASSERT(be16_to_cpu(bf[1].length) >= be16_to_cpu(bf[2].length));
100 /*
101 * Loop over the data/unused entries.
102 */
103 while (p < endp) {
104 dup = (xfs_dir2_data_unused_t *)p;
105 /*
106 * If it's unused, look for the space in the bestfree table.
107 * If we find it, account for that, else make sure it
108 * doesn't need to be there.
109 */
110 if (be16_to_cpu(dup->freetag) == XFS_DIR2_DATA_FREE_TAG) {
111 ASSERT(lastfree == 0);
112 ASSERT(be16_to_cpu(*xfs_dir2_data_unused_tag_p(dup)) ==
113 (char *)dup - (char *)hdr);
114 dfp = xfs_dir2_data_freefind(hdr, dup);
115 if (dfp) {
116 i = (int)(dfp - bf);
117 ASSERT((freeseen & (1 << i)) == 0);
118 freeseen |= 1 << i;
119 } else {
120 ASSERT(be16_to_cpu(dup->length) <=
121 be16_to_cpu(bf[2].length));
122 }
123 p += be16_to_cpu(dup->length);
124 lastfree = 1;
125 continue;
126 }
127 /*
128 * It's a real entry. Validate the fields.
129 * If this is a block directory then make sure it's
130 * in the leaf section of the block.
131 * The linear search is crude but this is DEBUG code.
132 */
133 dep = (xfs_dir2_data_entry_t *)p;
134 ASSERT(dep->namelen != 0);
135 ASSERT(xfs_dir_ino_validate(mp, be64_to_cpu(dep->inumber)) == 0);
136 ASSERT(be16_to_cpu(*xfs_dir2_data_entry_tag_p(dep)) ==
137 (char *)dep - (char *)hdr);
138 count++;
139 lastfree = 0;
140 if (hdr->magic == cpu_to_be32(XFS_DIR2_BLOCK_MAGIC)) {
141 addr = xfs_dir2_db_off_to_dataptr(mp, mp->m_dirdatablk,
142 (xfs_dir2_data_aoff_t)
143 ((char *)dep - (char *)hdr));
144 name.name = dep->name;
145 name.len = dep->namelen;
146 hash = mp->m_dirnameops->hashname(&name);
147 for (i = 0; i < be32_to_cpu(btp->count); i++) {
148 if (be32_to_cpu(lep[i].address) == addr &&
149 be32_to_cpu(lep[i].hashval) == hash)
150 break;
151 }
152 ASSERT(i < be32_to_cpu(btp->count));
153 }
154 p += xfs_dir2_data_entsize(dep->namelen);
155 }
156 /*
157 * Need to have seen all the entries and all the bestfree slots.
158 */
159 ASSERT(freeseen == 7);
160 if (hdr->magic == cpu_to_be32(XFS_DIR2_BLOCK_MAGIC)) {
161 for (i = stale = 0; i < be32_to_cpu(btp->count); i++) {
162 if (lep[i].address ==
163 cpu_to_be32(XFS_DIR2_NULL_DATAPTR))
164 stale++;
165 if (i > 0)
166 ASSERT(be32_to_cpu(lep[i].hashval) >= be32_to_cpu(lep[i - 1].hashval));
167 }
168 ASSERT(count == be32_to_cpu(btp->count) - be32_to_cpu(btp->stale));
169 ASSERT(stale == be32_to_cpu(btp->stale));
170 }
171 }
172 #endif
173
174 /*
175 * Given a data block and an unused entry from that block,
176 * return the bestfree entry if any that corresponds to it.
177 */
178 STATIC xfs_dir2_data_free_t *
179 xfs_dir2_data_freefind(
180 xfs_dir2_data_hdr_t *hdr, /* data block */
181 xfs_dir2_data_unused_t *dup) /* data unused entry */
182 {
183 xfs_dir2_data_free_t *dfp; /* bestfree entry */
184 xfs_dir2_data_aoff_t off; /* offset value needed */
185 #if defined(DEBUG) && defined(__KERNEL__)
186 int matched; /* matched the value */
187 int seenzero; /* saw a 0 bestfree entry */
188 #endif
189
190 off = (xfs_dir2_data_aoff_t)((char *)dup - (char *)hdr);
191 #if defined(DEBUG) && defined(__KERNEL__)
192 /*
193 * Validate some consistency in the bestfree table.
194 * Check order, non-overlapping entries, and if we find the
195 * one we're looking for it has to be exact.
196 */
197 ASSERT(hdr->magic == cpu_to_be32(XFS_DIR2_DATA_MAGIC) ||
198 hdr->magic == cpu_to_be32(XFS_DIR2_BLOCK_MAGIC));
199 for (dfp = &hdr->bestfree[0], seenzero = matched = 0;
200 dfp < &hdr->bestfree[XFS_DIR2_DATA_FD_COUNT];
201 dfp++) {
202 if (!dfp->offset) {
203 ASSERT(!dfp->length);
204 seenzero = 1;
205 continue;
206 }
207 ASSERT(seenzero == 0);
208 if (be16_to_cpu(dfp->offset) == off) {
209 matched = 1;
210 ASSERT(dfp->length == dup->length);
211 } else if (off < be16_to_cpu(dfp->offset))
212 ASSERT(off + be16_to_cpu(dup->length) <= be16_to_cpu(dfp->offset));
213 else
214 ASSERT(be16_to_cpu(dfp->offset) + be16_to_cpu(dfp->length) <= off);
215 ASSERT(matched || be16_to_cpu(dfp->length) >= be16_to_cpu(dup->length));
216 if (dfp > &hdr->bestfree[0])
217 ASSERT(be16_to_cpu(dfp[-1].length) >= be16_to_cpu(dfp[0].length));
218 }
219 #endif
220 /*
221 * If this is smaller than the smallest bestfree entry,
222 * it can't be there since they're sorted.
223 */
224 if (be16_to_cpu(dup->length) <
225 be16_to_cpu(hdr->bestfree[XFS_DIR2_DATA_FD_COUNT - 1].length))
226 return NULL;
227 /*
228 * Look at the three bestfree entries for our guy.
229 */
230 for (dfp = &hdr->bestfree[0];
231 dfp < &hdr->bestfree[XFS_DIR2_DATA_FD_COUNT];
232 dfp++) {
233 if (!dfp->offset)
234 return NULL;
235 if (be16_to_cpu(dfp->offset) == off)
236 return dfp;
237 }
238 /*
239 * Didn't find it. This only happens if there are duplicate lengths.
240 */
241 return NULL;
242 }
243
244 /*
245 * Insert an unused-space entry into the bestfree table.
246 */
247 xfs_dir2_data_free_t * /* entry inserted */
248 xfs_dir2_data_freeinsert(
249 xfs_dir2_data_hdr_t *hdr, /* data block pointer */
250 xfs_dir2_data_unused_t *dup, /* unused space */
251 int *loghead) /* log the data header (out) */
252 {
253 xfs_dir2_data_free_t *dfp; /* bestfree table pointer */
254 xfs_dir2_data_free_t new; /* new bestfree entry */
255
256 #ifdef __KERNEL__
257 ASSERT(hdr->magic == cpu_to_be32(XFS_DIR2_DATA_MAGIC) ||
258 hdr->magic == cpu_to_be32(XFS_DIR2_BLOCK_MAGIC));
259 #endif
260 dfp = hdr->bestfree;
261 new.length = dup->length;
262 new.offset = cpu_to_be16((char *)dup - (char *)hdr);
263
264 /*
265 * Insert at position 0, 1, or 2; or not at all.
266 */
267 if (be16_to_cpu(new.length) > be16_to_cpu(dfp[0].length)) {
268 dfp[2] = dfp[1];
269 dfp[1] = dfp[0];
270 dfp[0] = new;
271 *loghead = 1;
272 return &dfp[0];
273 }
274 if (be16_to_cpu(new.length) > be16_to_cpu(dfp[1].length)) {
275 dfp[2] = dfp[1];
276 dfp[1] = new;
277 *loghead = 1;
278 return &dfp[1];
279 }
280 if (be16_to_cpu(new.length) > be16_to_cpu(dfp[2].length)) {
281 dfp[2] = new;
282 *loghead = 1;
283 return &dfp[2];
284 }
285 return NULL;
286 }
287
288 /*
289 * Remove a bestfree entry from the table.
290 */
291 STATIC void
292 xfs_dir2_data_freeremove(
293 xfs_dir2_data_hdr_t *hdr, /* data block header */
294 xfs_dir2_data_free_t *dfp, /* bestfree entry pointer */
295 int *loghead) /* out: log data header */
296 {
297 #ifdef __KERNEL__
298 ASSERT(hdr->magic == cpu_to_be32(XFS_DIR2_DATA_MAGIC) ||
299 hdr->magic == cpu_to_be32(XFS_DIR2_BLOCK_MAGIC));
300 #endif
301 /*
302 * It's the first entry, slide the next 2 up.
303 */
304 if (dfp == &hdr->bestfree[0]) {
305 hdr->bestfree[0] = hdr->bestfree[1];
306 hdr->bestfree[1] = hdr->bestfree[2];
307 }
308 /*
309 * It's the second entry, slide the 3rd entry up.
310 */
311 else if (dfp == &hdr->bestfree[1])
312 hdr->bestfree[1] = hdr->bestfree[2];
313 /*
314 * Must be the last entry.
315 */
316 else
317 ASSERT(dfp == &hdr->bestfree[2]);
318 /*
319 * Clear the 3rd entry, must be zero now.
320 */
321 hdr->bestfree[2].length = 0;
322 hdr->bestfree[2].offset = 0;
323 *loghead = 1;
324 }
325
326 /*
327 * Given a data block, reconstruct its bestfree map.
328 */
329 void
330 xfs_dir2_data_freescan(
331 xfs_mount_t *mp, /* filesystem mount point */
332 xfs_dir2_data_hdr_t *hdr, /* data block header */
333 int *loghead) /* out: log data header */
334 {
335 xfs_dir2_block_tail_t *btp; /* block tail */
336 xfs_dir2_data_entry_t *dep; /* active data entry */
337 xfs_dir2_data_unused_t *dup; /* unused data entry */
338 char *endp; /* end of block's data */
339 char *p; /* current entry pointer */
340
341 #ifdef __KERNEL__
342 ASSERT(hdr->magic == cpu_to_be32(XFS_DIR2_DATA_MAGIC) ||
343 hdr->magic == cpu_to_be32(XFS_DIR2_BLOCK_MAGIC));
344 #endif
345 /*
346 * Start by clearing the table.
347 */
348 memset(hdr->bestfree, 0, sizeof(hdr->bestfree));
349 *loghead = 1;
350 /*
351 * Set up pointers.
352 */
353 p = (char *)(hdr + 1);
354 if (hdr->magic == cpu_to_be32(XFS_DIR2_BLOCK_MAGIC)) {
355 btp = xfs_dir2_block_tail_p(mp, hdr);
356 endp = (char *)xfs_dir2_block_leaf_p(btp);
357 } else
358 endp = (char *)hdr + mp->m_dirblksize;
359 /*
360 * Loop over the block's entries.
361 */
362 while (p < endp) {
363 dup = (xfs_dir2_data_unused_t *)p;
364 /*
365 * If it's a free entry, insert it.
366 */
367 if (be16_to_cpu(dup->freetag) == XFS_DIR2_DATA_FREE_TAG) {
368 ASSERT((char *)dup - (char *)hdr ==
369 be16_to_cpu(*xfs_dir2_data_unused_tag_p(dup)));
370 xfs_dir2_data_freeinsert(hdr, dup, loghead);
371 p += be16_to_cpu(dup->length);
372 }
373 /*
374 * For active entries, check their tags and skip them.
375 */
376 else {
377 dep = (xfs_dir2_data_entry_t *)p;
378 ASSERT((char *)dep - (char *)hdr ==
379 be16_to_cpu(*xfs_dir2_data_entry_tag_p(dep)));
380 p += xfs_dir2_data_entsize(dep->namelen);
381 }
382 }
383 }
384
385 /*
386 * Initialize a data block at the given block number in the directory.
387 * Give back the buffer for the created block.
388 */
389 int /* error */
390 xfs_dir2_data_init(
391 xfs_da_args_t *args, /* directory operation args */
392 xfs_dir2_db_t blkno, /* logical dir block number */
393 xfs_dabuf_t **bpp) /* output block buffer */
394 {
395 xfs_dabuf_t *bp; /* block buffer */
396 xfs_dir2_data_hdr_t *hdr; /* data block header */
397 xfs_inode_t *dp; /* incore directory inode */
398 xfs_dir2_data_unused_t *dup; /* unused entry pointer */
399 int error; /* error return value */
400 int i; /* bestfree index */
401 xfs_mount_t *mp; /* filesystem mount point */
402 xfs_trans_t *tp; /* transaction pointer */
403 int t; /* temp */
404
405 dp = args->dp;
406 mp = dp->i_mount;
407 tp = args->trans;
408 /*
409 * Get the buffer set up for the block.
410 */
411 error = xfs_da_get_buf(tp, dp, xfs_dir2_db_to_da(mp, blkno), -1, &bp,
412 XFS_DATA_FORK);
413 if (error) {
414 return error;
415 }
416 ASSERT(bp != NULL);
417
418 /*
419 * Initialize the header.
420 */
421 hdr = bp->data;
422 hdr->magic = cpu_to_be32(XFS_DIR2_DATA_MAGIC);
423 hdr->bestfree[0].offset = cpu_to_be16(sizeof(*hdr));
424 for (i = 1; i < XFS_DIR2_DATA_FD_COUNT; i++) {
425 hdr->bestfree[i].length = 0;
426 hdr->bestfree[i].offset = 0;
427 }
428
429 /*
430 * Set up an unused entry for the block's body.
431 */
432 dup = (xfs_dir2_data_unused_t *)(hdr + 1);
433 dup->freetag = cpu_to_be16(XFS_DIR2_DATA_FREE_TAG);
434
435 t = mp->m_dirblksize - (uint)sizeof(*hdr);
436 hdr->bestfree[0].length = cpu_to_be16(t);
437 dup->length = cpu_to_be16(t);
438 *xfs_dir2_data_unused_tag_p(dup) = cpu_to_be16((char *)dup - (char *)hdr);
439 /*
440 * Log it and return it.
441 */
442 xfs_dir2_data_log_header(tp, bp);
443 xfs_dir2_data_log_unused(tp, bp, dup);
444 *bpp = bp;
445 return 0;
446 }
447
448 /*
449 * Log an active data entry from the block.
450 */
451 void
452 xfs_dir2_data_log_entry(
453 xfs_trans_t *tp, /* transaction pointer */
454 xfs_dabuf_t *bp, /* block buffer */
455 xfs_dir2_data_entry_t *dep) /* data entry pointer */
456 {
457 xfs_dir2_data_hdr_t *hdr = bp->data;
458
459 ASSERT(hdr->magic == cpu_to_be32(XFS_DIR2_DATA_MAGIC) ||
460 hdr->magic == cpu_to_be32(XFS_DIR2_BLOCK_MAGIC));
461
462 xfs_da_log_buf(tp, bp, (uint)((char *)dep - (char *)hdr),
463 (uint)((char *)(xfs_dir2_data_entry_tag_p(dep) + 1) -
464 (char *)hdr - 1));
465 }
466
467 /*
468 * Log a data block header.
469 */
470 void
471 xfs_dir2_data_log_header(
472 xfs_trans_t *tp, /* transaction pointer */
473 xfs_dabuf_t *bp) /* block buffer */
474 {
475 xfs_dir2_data_hdr_t *hdr = bp->data;
476
477 ASSERT(hdr->magic == cpu_to_be32(XFS_DIR2_DATA_MAGIC) ||
478 hdr->magic == cpu_to_be32(XFS_DIR2_BLOCK_MAGIC));
479
480 xfs_da_log_buf(tp, bp, 0, sizeof(*hdr) - 1);
481 }
482
483 /*
484 * Log a data unused entry.
485 */
486 void
487 xfs_dir2_data_log_unused(
488 xfs_trans_t *tp, /* transaction pointer */
489 xfs_dabuf_t *bp, /* block buffer */
490 xfs_dir2_data_unused_t *dup) /* data unused pointer */
491 {
492 xfs_dir2_data_hdr_t *hdr = bp->data;
493
494 ASSERT(hdr->magic == cpu_to_be32(XFS_DIR2_DATA_MAGIC) ||
495 hdr->magic == cpu_to_be32(XFS_DIR2_BLOCK_MAGIC));
496
497 /*
498 * Log the first part of the unused entry.
499 */
500 xfs_da_log_buf(tp, bp, (uint)((char *)dup - (char *)hdr),
501 (uint)((char *)&dup->length + sizeof(dup->length) -
502 1 - (char *)hdr));
503 /*
504 * Log the end (tag) of the unused entry.
505 */
506 xfs_da_log_buf(tp, bp,
507 (uint)((char *)xfs_dir2_data_unused_tag_p(dup) - (char *)hdr),
508 (uint)((char *)xfs_dir2_data_unused_tag_p(dup) - (char *)hdr +
509 sizeof(xfs_dir2_data_off_t) - 1));
510 }
511
512 /*
513 * Make a byte range in the data block unused.
514 * Its current contents are unimportant.
515 */
516 void
517 xfs_dir2_data_make_free(
518 xfs_trans_t *tp, /* transaction pointer */
519 xfs_dabuf_t *bp, /* block buffer */
520 xfs_dir2_data_aoff_t offset, /* starting byte offset */
521 xfs_dir2_data_aoff_t len, /* length in bytes */
522 int *needlogp, /* out: log header */
523 int *needscanp) /* out: regen bestfree */
524 {
525 xfs_dir2_data_hdr_t *hdr; /* data block pointer */
526 xfs_dir2_data_free_t *dfp; /* bestfree pointer */
527 char *endptr; /* end of data area */
528 xfs_mount_t *mp; /* filesystem mount point */
529 int needscan; /* need to regen bestfree */
530 xfs_dir2_data_unused_t *newdup; /* new unused entry */
531 xfs_dir2_data_unused_t *postdup; /* unused entry after us */
532 xfs_dir2_data_unused_t *prevdup; /* unused entry before us */
533
534 mp = tp->t_mountp;
535 hdr = bp->data;
536
537 /*
538 * Figure out where the end of the data area is.
539 */
540 if (hdr->magic == cpu_to_be32(XFS_DIR2_DATA_MAGIC))
541 endptr = (char *)hdr + mp->m_dirblksize;
542 else {
543 xfs_dir2_block_tail_t *btp; /* block tail */
544
545 ASSERT(hdr->magic == cpu_to_be32(XFS_DIR2_BLOCK_MAGIC));
546 btp = xfs_dir2_block_tail_p(mp, hdr);
547 endptr = (char *)xfs_dir2_block_leaf_p(btp);
548 }
549 /*
550 * If this isn't the start of the block, then back up to
551 * the previous entry and see if it's free.
552 */
553 if (offset > sizeof(*hdr)) {
554 __be16 *tagp; /* tag just before us */
555
556 tagp = (__be16 *)((char *)hdr + offset) - 1;
557 prevdup = (xfs_dir2_data_unused_t *)((char *)hdr + be16_to_cpu(*tagp));
558 if (be16_to_cpu(prevdup->freetag) != XFS_DIR2_DATA_FREE_TAG)
559 prevdup = NULL;
560 } else
561 prevdup = NULL;
562 /*
563 * If this isn't the end of the block, see if the entry after
564 * us is free.
565 */
566 if ((char *)hdr + offset + len < endptr) {
567 postdup =
568 (xfs_dir2_data_unused_t *)((char *)hdr + offset + len);
569 if (be16_to_cpu(postdup->freetag) != XFS_DIR2_DATA_FREE_TAG)
570 postdup = NULL;
571 } else
572 postdup = NULL;
573 ASSERT(*needscanp == 0);
574 needscan = 0;
575 /*
576 * Previous and following entries are both free,
577 * merge everything into a single free entry.
578 */
579 if (prevdup && postdup) {
580 xfs_dir2_data_free_t *dfp2; /* another bestfree pointer */
581
582 /*
583 * See if prevdup and/or postdup are in bestfree table.
584 */
585 dfp = xfs_dir2_data_freefind(hdr, prevdup);
586 dfp2 = xfs_dir2_data_freefind(hdr, postdup);
587 /*
588 * We need a rescan unless there are exactly 2 free entries
589 * namely our two. Then we know what's happening, otherwise
590 * since the third bestfree is there, there might be more
591 * entries.
592 */
593 needscan = (hdr->bestfree[2].length != 0);
594 /*
595 * Fix up the new big freespace.
596 */
597 be16_add_cpu(&prevdup->length, len + be16_to_cpu(postdup->length));
598 *xfs_dir2_data_unused_tag_p(prevdup) =
599 cpu_to_be16((char *)prevdup - (char *)hdr);
600 xfs_dir2_data_log_unused(tp, bp, prevdup);
601 if (!needscan) {
602 /*
603 * Has to be the case that entries 0 and 1 are
604 * dfp and dfp2 (don't know which is which), and
605 * entry 2 is empty.
606 * Remove entry 1 first then entry 0.
607 */
608 ASSERT(dfp && dfp2);
609 if (dfp == &hdr->bestfree[1]) {
610 dfp = &hdr->bestfree[0];
611 ASSERT(dfp2 == dfp);
612 dfp2 = &hdr->bestfree[1];
613 }
614 xfs_dir2_data_freeremove(hdr, dfp2, needlogp);
615 xfs_dir2_data_freeremove(hdr, dfp, needlogp);
616 /*
617 * Now insert the new entry.
618 */
619 dfp = xfs_dir2_data_freeinsert(hdr, prevdup, needlogp);
620 ASSERT(dfp == &hdr->bestfree[0]);
621 ASSERT(dfp->length == prevdup->length);
622 ASSERT(!dfp[1].length);
623 ASSERT(!dfp[2].length);
624 }
625 }
626 /*
627 * The entry before us is free, merge with it.
628 */
629 else if (prevdup) {
630 dfp = xfs_dir2_data_freefind(hdr, prevdup);
631 be16_add_cpu(&prevdup->length, len);
632 *xfs_dir2_data_unused_tag_p(prevdup) =
633 cpu_to_be16((char *)prevdup - (char *)hdr);
634 xfs_dir2_data_log_unused(tp, bp, prevdup);
635 /*
636 * If the previous entry was in the table, the new entry
637 * is longer, so it will be in the table too. Remove
638 * the old one and add the new one.
639 */
640 if (dfp) {
641 xfs_dir2_data_freeremove(hdr, dfp, needlogp);
642 xfs_dir2_data_freeinsert(hdr, prevdup, needlogp);
643 }
644 /*
645 * Otherwise we need a scan if the new entry is big enough.
646 */
647 else {
648 needscan = be16_to_cpu(prevdup->length) >
649 be16_to_cpu(hdr->bestfree[2].length);
650 }
651 }
652 /*
653 * The following entry is free, merge with it.
654 */
655 else if (postdup) {
656 dfp = xfs_dir2_data_freefind(hdr, postdup);
657 newdup = (xfs_dir2_data_unused_t *)((char *)hdr + offset);
658 newdup->freetag = cpu_to_be16(XFS_DIR2_DATA_FREE_TAG);
659 newdup->length = cpu_to_be16(len + be16_to_cpu(postdup->length));
660 *xfs_dir2_data_unused_tag_p(newdup) =
661 cpu_to_be16((char *)newdup - (char *)hdr);
662 xfs_dir2_data_log_unused(tp, bp, newdup);
663 /*
664 * If the following entry was in the table, the new entry
665 * is longer, so it will be in the table too. Remove
666 * the old one and add the new one.
667 */
668 if (dfp) {
669 xfs_dir2_data_freeremove(hdr, dfp, needlogp);
670 xfs_dir2_data_freeinsert(hdr, newdup, needlogp);
671 }
672 /*
673 * Otherwise we need a scan if the new entry is big enough.
674 */
675 else {
676 needscan = be16_to_cpu(newdup->length) >
677 be16_to_cpu(hdr->bestfree[2].length);
678 }
679 }
680 /*
681 * Neither neighbor is free. Make a new entry.
682 */
683 else {
684 newdup = (xfs_dir2_data_unused_t *)((char *)hdr + offset);
685 newdup->freetag = cpu_to_be16(XFS_DIR2_DATA_FREE_TAG);
686 newdup->length = cpu_to_be16(len);
687 *xfs_dir2_data_unused_tag_p(newdup) =
688 cpu_to_be16((char *)newdup - (char *)hdr);
689 xfs_dir2_data_log_unused(tp, bp, newdup);
690 xfs_dir2_data_freeinsert(hdr, newdup, needlogp);
691 }
692 *needscanp = needscan;
693 }
694
695 /*
696 * Take a byte range out of an existing unused space and make it un-free.
697 */
698 void
699 xfs_dir2_data_use_free(
700 xfs_trans_t *tp, /* transaction pointer */
701 xfs_dabuf_t *bp, /* data block buffer */
702 xfs_dir2_data_unused_t *dup, /* unused entry */
703 xfs_dir2_data_aoff_t offset, /* starting offset to use */
704 xfs_dir2_data_aoff_t len, /* length to use */
705 int *needlogp, /* out: need to log header */
706 int *needscanp) /* out: need regen bestfree */
707 {
708 xfs_dir2_data_hdr_t *hdr; /* data block header */
709 xfs_dir2_data_free_t *dfp; /* bestfree pointer */
710 int matchback; /* matches end of freespace */
711 int matchfront; /* matches start of freespace */
712 int needscan; /* need to regen bestfree */
713 xfs_dir2_data_unused_t *newdup; /* new unused entry */
714 xfs_dir2_data_unused_t *newdup2; /* another new unused entry */
715 int oldlen; /* old unused entry's length */
716
717 hdr = bp->data;
718 ASSERT(hdr->magic == cpu_to_be32(XFS_DIR2_DATA_MAGIC) ||
719 hdr->magic == cpu_to_be32(XFS_DIR2_BLOCK_MAGIC));
720 ASSERT(be16_to_cpu(dup->freetag) == XFS_DIR2_DATA_FREE_TAG);
721 ASSERT(offset >= (char *)dup - (char *)hdr);
722 ASSERT(offset + len <= (char *)dup + be16_to_cpu(dup->length) - (char *)hdr);
723 ASSERT((char *)dup - (char *)hdr == be16_to_cpu(*xfs_dir2_data_unused_tag_p(dup)));
724 /*
725 * Look up the entry in the bestfree table.
726 */
727 dfp = xfs_dir2_data_freefind(hdr, dup);
728 oldlen = be16_to_cpu(dup->length);
729 ASSERT(dfp || oldlen <= be16_to_cpu(hdr->bestfree[2].length));
730 /*
731 * Check for alignment with front and back of the entry.
732 */
733 matchfront = (char *)dup - (char *)hdr == offset;
734 matchback = (char *)dup + oldlen - (char *)hdr == offset + len;
735 ASSERT(*needscanp == 0);
736 needscan = 0;
737 /*
738 * If we matched it exactly we just need to get rid of it from
739 * the bestfree table.
740 */
741 if (matchfront && matchback) {
742 if (dfp) {
743 needscan = (hdr->bestfree[2].offset != 0);
744 if (!needscan)
745 xfs_dir2_data_freeremove(hdr, dfp, needlogp);
746 }
747 }
748 /*
749 * We match the first part of the entry.
750 * Make a new entry with the remaining freespace.
751 */
752 else if (matchfront) {
753 newdup = (xfs_dir2_data_unused_t *)((char *)hdr + offset + len);
754 newdup->freetag = cpu_to_be16(XFS_DIR2_DATA_FREE_TAG);
755 newdup->length = cpu_to_be16(oldlen - len);
756 *xfs_dir2_data_unused_tag_p(newdup) =
757 cpu_to_be16((char *)newdup - (char *)hdr);
758 xfs_dir2_data_log_unused(tp, bp, newdup);
759 /*
760 * If it was in the table, remove it and add the new one.
761 */
762 if (dfp) {
763 xfs_dir2_data_freeremove(hdr, dfp, needlogp);
764 dfp = xfs_dir2_data_freeinsert(hdr, newdup, needlogp);
765 ASSERT(dfp != NULL);
766 ASSERT(dfp->length == newdup->length);
767 ASSERT(be16_to_cpu(dfp->offset) == (char *)newdup - (char *)hdr);
768 /*
769 * If we got inserted at the last slot,
770 * that means we don't know if there was a better
771 * choice for the last slot, or not. Rescan.
772 */
773 needscan = dfp == &hdr->bestfree[2];
774 }
775 }
776 /*
777 * We match the last part of the entry.
778 * Trim the allocated space off the tail of the entry.
779 */
780 else if (matchback) {
781 newdup = dup;
782 newdup->length = cpu_to_be16(((char *)hdr + offset) - (char *)newdup);
783 *xfs_dir2_data_unused_tag_p(newdup) =
784 cpu_to_be16((char *)newdup - (char *)hdr);
785 xfs_dir2_data_log_unused(tp, bp, newdup);
786 /*
787 * If it was in the table, remove it and add the new one.
788 */
789 if (dfp) {
790 xfs_dir2_data_freeremove(hdr, dfp, needlogp);
791 dfp = xfs_dir2_data_freeinsert(hdr, newdup, needlogp);
792 ASSERT(dfp != NULL);
793 ASSERT(dfp->length == newdup->length);
794 ASSERT(be16_to_cpu(dfp->offset) == (char *)newdup - (char *)hdr);
795 /*
796 * If we got inserted at the last slot,
797 * that means we don't know if there was a better
798 * choice for the last slot, or not. Rescan.
799 */
800 needscan = dfp == &hdr->bestfree[2];
801 }
802 }
803 /*
804 * Poking out the middle of an entry.
805 * Make two new entries.
806 */
807 else {
808 newdup = dup;
809 newdup->length = cpu_to_be16(((char *)hdr + offset) - (char *)newdup);
810 *xfs_dir2_data_unused_tag_p(newdup) =
811 cpu_to_be16((char *)newdup - (char *)hdr);
812 xfs_dir2_data_log_unused(tp, bp, newdup);
813 newdup2 = (xfs_dir2_data_unused_t *)((char *)hdr + offset + len);
814 newdup2->freetag = cpu_to_be16(XFS_DIR2_DATA_FREE_TAG);
815 newdup2->length = cpu_to_be16(oldlen - len - be16_to_cpu(newdup->length));
816 *xfs_dir2_data_unused_tag_p(newdup2) =
817 cpu_to_be16((char *)newdup2 - (char *)hdr);
818 xfs_dir2_data_log_unused(tp, bp, newdup2);
819 /*
820 * If the old entry was in the table, we need to scan
821 * if the 3rd entry was valid, since these entries
822 * are smaller than the old one.
823 * If we don't need to scan that means there were 1 or 2
824 * entries in the table, and removing the old and adding
825 * the 2 new will work.
826 */
827 if (dfp) {
828 needscan = (hdr->bestfree[2].length != 0);
829 if (!needscan) {
830 xfs_dir2_data_freeremove(hdr, dfp, needlogp);
831 xfs_dir2_data_freeinsert(hdr, newdup, needlogp);
832 xfs_dir2_data_freeinsert(hdr, newdup2,
833 needlogp);
834 }
835 }
836 }
837 *needscanp = needscan;
838 }
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