1 | /* $NetBSD: ufs_lookup.c,v 1.145 2016/04/29 02:38:19 christos Exp $ */ |
2 | |
3 | /* |
4 | * Copyright (c) 1989, 1993 |
5 | * The Regents of the University of California. All rights reserved. |
6 | * (c) UNIX System Laboratories, Inc. |
7 | * All or some portions of this file are derived from material licensed |
8 | * to the University of California by American Telephone and Telegraph |
9 | * Co. or Unix System Laboratories, Inc. and are reproduced herein with |
10 | * the permission of UNIX System Laboratories, Inc. |
11 | * |
12 | * Redistribution and use in source and binary forms, with or without |
13 | * modification, are permitted provided that the following conditions |
14 | * are met: |
15 | * 1. Redistributions of source code must retain the above copyright |
16 | * notice, this list of conditions and the following disclaimer. |
17 | * 2. Redistributions in binary form must reproduce the above copyright |
18 | * notice, this list of conditions and the following disclaimer in the |
19 | * documentation and/or other materials provided with the distribution. |
20 | * 3. Neither the name of the University nor the names of its contributors |
21 | * may be used to endorse or promote products derived from this software |
22 | * without specific prior written permission. |
23 | * |
24 | * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND |
25 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
26 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
27 | * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE |
28 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
29 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS |
30 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
31 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
32 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY |
33 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
34 | * SUCH DAMAGE. |
35 | * |
36 | * @(#)ufs_lookup.c 8.9 (Berkeley) 8/11/94 |
37 | */ |
38 | |
39 | #include <sys/cdefs.h> |
40 | __KERNEL_RCSID(0, "$NetBSD: ufs_lookup.c,v 1.145 2016/04/29 02:38:19 christos Exp $" ); |
41 | |
42 | #ifdef _KERNEL_OPT |
43 | #include "opt_ffs.h" |
44 | #endif |
45 | |
46 | #include <sys/param.h> |
47 | #include <sys/systm.h> |
48 | #include <sys/namei.h> |
49 | #include <sys/buf.h> |
50 | #include <sys/file.h> |
51 | #include <sys/stat.h> |
52 | #include <sys/mount.h> |
53 | #include <sys/vnode.h> |
54 | #include <sys/kernel.h> |
55 | #include <sys/kauth.h> |
56 | #include <sys/wapbl.h> |
57 | #include <sys/fstrans.h> |
58 | #include <sys/proc.h> |
59 | #include <sys/kmem.h> |
60 | |
61 | #include <ufs/ufs/inode.h> |
62 | #include <ufs/ufs/dir.h> |
63 | #ifdef UFS_DIRHASH |
64 | #include <ufs/ufs/dirhash.h> |
65 | #endif |
66 | #include <ufs/ufs/ufsmount.h> |
67 | #include <ufs/ufs/ufs_extern.h> |
68 | #include <ufs/ufs/ufs_bswap.h> |
69 | #include <ufs/ufs/ufs_wapbl.h> |
70 | |
71 | #include <miscfs/genfs/genfs.h> |
72 | |
73 | #ifdef DIAGNOSTIC |
74 | int dirchk = 1; |
75 | #else |
76 | int dirchk = 0; |
77 | #endif |
78 | |
79 | #if BYTE_ORDER == LITTLE_ENDIAN |
80 | # define ENDIANSWAP(needswap) ((needswap) == 0) |
81 | #else |
82 | # define ENDIANSWAP(needswap) ((needswap) != 0) |
83 | #endif |
84 | |
85 | #define NAMLEN(fsfmt, needswap, dp) \ |
86 | ((fsfmt) && ENDIANSWAP(needswap) ? (dp)->d_type : (dp)->d_namlen) |
87 | |
88 | static void |
89 | ufs_dirswap(struct direct *dirp) |
90 | { |
91 | uint8_t tmp = dirp->d_namlen; |
92 | dirp->d_namlen = dirp->d_type; |
93 | dirp->d_type = tmp; |
94 | } |
95 | |
96 | struct slotinfo { |
97 | enum { |
98 | NONE, /* need to search a slot for our new entry */ |
99 | COMPACT, /* a compaction can make a slot in the current |
100 | DIRBLKSIZ block */ |
101 | FOUND, /* found a slot (or no need to search) */ |
102 | } status; |
103 | doff_t offset; /* offset of area with free space. |
104 | a special value -1 for invalid */ |
105 | int size; /* size of area at slotoffset */ |
106 | int freespace; /* accumulated amount of space free in |
107 | the current DIRBLKSIZ block */ |
108 | int needed; /* size of the entry we're seeking */ |
109 | }; |
110 | |
111 | static void |
112 | calc_count(struct ufs_lookup_results *results, int dirblksiz, doff_t prevoff) |
113 | { |
114 | if ((results->ulr_offset & (dirblksiz - 1)) == 0) |
115 | results->ulr_count = 0; |
116 | else |
117 | results->ulr_count = results->ulr_offset - prevoff; |
118 | } |
119 | |
120 | static void |
121 | slot_init(struct slotinfo *slot) |
122 | { |
123 | slot->status = FOUND; |
124 | slot->offset = -1; |
125 | slot->freespace = slot->size = slot->needed = 0; |
126 | } |
127 | |
128 | #ifdef UFS_DIRHASH |
129 | static doff_t |
130 | slot_findfree(struct slotinfo *slot, struct inode *dp) |
131 | { |
132 | if (slot->status == FOUND) |
133 | return dp->i_size; |
134 | |
135 | slot->offset = ufsdirhash_findfree(dp, slot->needed, &slot->size); |
136 | if (slot->offset < 0) |
137 | return dp->i_size; |
138 | |
139 | slot->status = COMPACT; |
140 | doff_t enduseful = ufsdirhash_enduseful(dp); |
141 | if (enduseful < 0) |
142 | return dp->i_size; |
143 | return enduseful; |
144 | } |
145 | #endif |
146 | |
147 | static void |
148 | slot_white(struct slotinfo *slot, uint16_t reclen, |
149 | struct ufs_lookup_results *results) |
150 | { |
151 | slot->status = FOUND; |
152 | slot->offset = results->ulr_offset; |
153 | slot->size = reclen; |
154 | results->ulr_reclen = slot->size; |
155 | } |
156 | |
157 | static void |
158 | slot_update(struct slotinfo *slot, int size, uint16_t reclen, doff_t offset) |
159 | { |
160 | if (size >= slot->needed) { |
161 | slot->status = FOUND; |
162 | slot->offset = offset; |
163 | slot->size = reclen; |
164 | } else if (slot->status == NONE) { |
165 | slot->freespace += size; |
166 | if (slot->offset == -1) |
167 | slot->offset = offset; |
168 | if (slot->freespace >= slot->needed) { |
169 | slot->status = COMPACT; |
170 | slot->size = offset + reclen - slot->offset; |
171 | } |
172 | } |
173 | } |
174 | |
175 | /* |
176 | * Return an indication of where the new directory entry should be put. |
177 | * If we didn't find a slot, then set results->ulr_count to 0 indicating |
178 | * that the new slot belongs at the end of the directory. If we found a slot, |
179 | * then the new entry can be put in the range from results->ulr_offset to |
180 | * results->ulr_offset + results->ulr_count. |
181 | */ |
182 | static int |
183 | slot_estimate(const struct slotinfo *slot, int dirblksiz, int nameiop, |
184 | doff_t prevoff, doff_t enduseful, const struct inode *ip, |
185 | struct ufs_lookup_results *results) |
186 | { |
187 | if (slot->status == NONE) { |
188 | results->ulr_offset = roundup(ip->i_size, dirblksiz); |
189 | results->ulr_count = 0; |
190 | enduseful = results->ulr_offset; |
191 | } else if (nameiop == DELETE) { |
192 | results->ulr_offset = slot->offset; |
193 | calc_count(results, dirblksiz, prevoff); |
194 | } else { |
195 | results->ulr_offset = slot->offset; |
196 | results->ulr_count = slot->size; |
197 | if (enduseful < slot->offset + slot->size) |
198 | enduseful = slot->offset + slot->size; |
199 | } |
200 | results->ulr_endoff = roundup(enduseful, dirblksiz); |
201 | #if 0 /* commented out by dbj. none of the on disk fields changed */ |
202 | ip->i_flag |= IN_CHANGE | IN_UPDATE; |
203 | #endif |
204 | return EJUSTRETURN; |
205 | } |
206 | |
207 | /* |
208 | * Check if we can delete inode tdp in directory vdp with inode ip and creds. |
209 | */ |
210 | static int |
211 | ufs_can_delete(struct vnode *tdp, struct vnode *vdp, struct inode *ip, |
212 | kauth_cred_t cred) |
213 | { |
214 | int error; |
215 | /* |
216 | * Write access to directory required to delete files. |
217 | */ |
218 | error = VOP_ACCESS(vdp, VWRITE, cred); |
219 | if (error) |
220 | goto out; |
221 | |
222 | if (!(ip->i_mode & ISVTX)) |
223 | return 0; |
224 | |
225 | /* |
226 | * If directory is "sticky", then user must own |
227 | * the directory, or the file in it, else she |
228 | * may not delete it (unless she's root). This |
229 | * implements append-only directories. |
230 | */ |
231 | error = kauth_authorize_vnode(cred, KAUTH_VNODE_DELETE, tdp, vdp, |
232 | genfs_can_sticky(cred, ip->i_uid, VTOI(tdp)->i_uid)); |
233 | if (error) { |
234 | error = EPERM; // Why override? |
235 | goto out; |
236 | } |
237 | return 0; |
238 | out: |
239 | vrele(tdp); |
240 | return error; |
241 | } |
242 | |
243 | static int |
244 | ufs_getino(struct vnode *vdp, struct inode *ip, ino_t foundino, |
245 | struct vnode **tdp, bool same) |
246 | { |
247 | if (ip->i_number == foundino) { |
248 | if (same) |
249 | return EISDIR; |
250 | vref(vdp); |
251 | *tdp = vdp; |
252 | return 0; |
253 | } |
254 | return vcache_get(vdp->v_mount, &foundino, sizeof(foundino), tdp); |
255 | } |
256 | |
257 | |
258 | /* |
259 | * Convert a component of a pathname into a pointer to a locked inode. |
260 | * This is a very central and rather complicated routine. |
261 | * If the file system is not maintained in a strict tree hierarchy, |
262 | * this can result in a deadlock situation (see comments in code below). |
263 | * |
264 | * The cnp->cn_nameiop argument is LOOKUP, CREATE, RENAME, or DELETE depending |
265 | * on whether the name is to be looked up, created, renamed, or deleted. |
266 | * When CREATE, RENAME, or DELETE is specified, information usable in |
267 | * creating, renaming, or deleting a directory entry may be calculated. |
268 | * If flag has LOCKPARENT or'ed into it and the target of the pathname |
269 | * exists, lookup returns both the target and its parent directory locked. |
270 | * When creating or renaming and LOCKPARENT is specified, the target may |
271 | * not be ".". When deleting and LOCKPARENT is specified, the target may |
272 | * be "."., but the caller must check to ensure it does an vrele and vput |
273 | * instead of two vputs. |
274 | * |
275 | * Overall outline of ufs_lookup: |
276 | * |
277 | * check accessibility of directory |
278 | * look for name in cache, if found, then if at end of path |
279 | * and deleting or creating, drop it, else return name |
280 | * search for name in directory, to found or notfound |
281 | * notfound: |
282 | * if creating, return locked directory, leaving info on available slots |
283 | * else return error |
284 | * found: |
285 | * if at end of path and deleting, return information to allow delete |
286 | * if at end of path and rewriting (RENAME and LOCKPARENT), lock target |
287 | * inode and return info to allow rewrite |
288 | * if not at end, add name to cache; if at end and neither creating |
289 | * nor deleting, add name to cache |
290 | */ |
291 | int |
292 | ufs_lookup(void *v) |
293 | { |
294 | struct vop_lookup_v2_args /* { |
295 | struct vnode *a_dvp; |
296 | struct vnode **a_vpp; |
297 | struct componentname *a_cnp; |
298 | } */ *ap = v; |
299 | struct vnode *vdp = ap->a_dvp; /* vnode for directory being searched */ |
300 | struct inode *dp = VTOI(vdp); /* inode for directory being searched */ |
301 | struct buf *bp; /* a buffer of directory entries */ |
302 | struct direct *ep; /* the current directory entry */ |
303 | int entryoffsetinblock; /* offset of ep in bp's buffer */ |
304 | struct slotinfo slot; |
305 | int numdirpasses; /* strategy for directory search */ |
306 | doff_t endsearch; /* offset to end directory search */ |
307 | doff_t prevoff; /* previous value of ulr_offset */ |
308 | struct vnode *tdp; /* returned by vcache_get */ |
309 | doff_t enduseful; /* pointer past last used dir slot. |
310 | used for directory truncation. */ |
311 | u_long bmask; /* block offset mask */ |
312 | int error; |
313 | struct vnode **vpp = ap->a_vpp; |
314 | struct componentname *cnp = ap->a_cnp; |
315 | kauth_cred_t cred = cnp->cn_cred; |
316 | int flags; |
317 | int nameiop = cnp->cn_nameiop; |
318 | struct ufsmount *ump = dp->i_ump; |
319 | const int needswap = UFS_MPNEEDSWAP(ump); |
320 | int dirblksiz = ump->um_dirblksiz; |
321 | ino_t foundino; |
322 | struct ufs_lookup_results *results; |
323 | int iswhiteout; /* temp result from cache_lookup() */ |
324 | const int fsfmt = FSFMT(vdp); |
325 | uint16_t reclen; |
326 | |
327 | flags = cnp->cn_flags; |
328 | |
329 | bp = NULL; |
330 | *vpp = NULL; |
331 | endsearch = 0; /* silence compiler warning */ |
332 | |
333 | /* |
334 | * Produce the auxiliary lookup results into i_crap. Increment |
335 | * its serial number so elsewhere we can tell if we're using |
336 | * stale results. This should not be done this way. XXX. |
337 | */ |
338 | results = &dp->i_crap; |
339 | dp->i_crapcounter++; |
340 | |
341 | /* |
342 | * Check accessiblity of directory. |
343 | */ |
344 | if ((error = VOP_ACCESS(vdp, VEXEC, cred)) != 0) |
345 | return (error); |
346 | |
347 | if ((flags & ISLASTCN) && (vdp->v_mount->mnt_flag & MNT_RDONLY) && |
348 | (nameiop == DELETE || nameiop == RENAME)) |
349 | return (EROFS); |
350 | |
351 | /* |
352 | * We now have a segment name to search for, and a directory to search. |
353 | * |
354 | * Before tediously performing a linear scan of the directory, |
355 | * check the name cache to see if the directory/name pair |
356 | * we are looking for is known already. |
357 | */ |
358 | if (cache_lookup(vdp, cnp->cn_nameptr, cnp->cn_namelen, |
359 | cnp->cn_nameiop, cnp->cn_flags, &iswhiteout, vpp)) { |
360 | if (iswhiteout) { |
361 | cnp->cn_flags |= ISWHITEOUT; |
362 | } |
363 | return *vpp == NULLVP ? ENOENT : 0; |
364 | } |
365 | if (iswhiteout) { |
366 | /* |
367 | * The namecache set iswhiteout without finding a |
368 | * cache entry. As of this writing (20121014), this |
369 | * can happen if there was a whiteout entry that has |
370 | * been invalidated by the lookup. It is not clear if |
371 | * it is correct to set ISWHITEOUT in this case or |
372 | * not; however, doing so retains the prior behavior, |
373 | * so we'll go with that until some clearer answer |
374 | * appears. XXX |
375 | */ |
376 | cnp->cn_flags |= ISWHITEOUT; |
377 | } |
378 | |
379 | fstrans_start(vdp->v_mount, FSTRANS_SHARED); |
380 | |
381 | /* |
382 | * Suppress search for slots unless creating |
383 | * file and at end of pathname, in which case |
384 | * we watch for a place to put the new file in |
385 | * case it doesn't already exist. |
386 | */ |
387 | slot_init(&slot); |
388 | |
389 | if ((nameiop == CREATE || nameiop == RENAME) && (flags & ISLASTCN)) { |
390 | slot.status = NONE; |
391 | slot.needed = UFS_DIRECTSIZ(cnp->cn_namelen); |
392 | } |
393 | |
394 | /* |
395 | * If there is cached information on a previous search of |
396 | * this directory, pick up where we last left off. |
397 | * We cache only lookups as these are the most common |
398 | * and have the greatest payoff. Caching CREATE has little |
399 | * benefit as it usually must search the entire directory |
400 | * to determine that the entry does not exist. Caching the |
401 | * location of the last DELETE or RENAME has not reduced |
402 | * profiling time and hence has been removed in the interest |
403 | * of simplicity. |
404 | */ |
405 | bmask = vdp->v_mount->mnt_stat.f_iosize - 1; |
406 | |
407 | #ifdef UFS_DIRHASH |
408 | /* |
409 | * Use dirhash for fast operations on large directories. The logic |
410 | * to determine whether to hash the directory is contained within |
411 | * ufsdirhash_build(); a zero return means that it decided to hash |
412 | * this directory and it successfully built up the hash table. |
413 | */ |
414 | if (ufsdirhash_build(dp) == 0) { |
415 | /* Look for a free slot if needed. */ |
416 | enduseful = slot_findfree(&slot, dp); |
417 | /* Look up the component. */ |
418 | numdirpasses = 1; |
419 | entryoffsetinblock = 0; /* silence compiler warning */ |
420 | switch (ufsdirhash_lookup(dp, cnp->cn_nameptr, cnp->cn_namelen, |
421 | &results->ulr_offset, &bp, |
422 | nameiop == DELETE ? &prevoff : NULL)) { |
423 | case 0: |
424 | ep = (void *)((char *)bp->b_data + |
425 | (results->ulr_offset & bmask)); |
426 | reclen = ufs_rw16(ep->d_reclen, needswap); |
427 | goto foundentry; |
428 | case ENOENT: |
429 | results->ulr_offset = roundup(dp->i_size, dirblksiz); |
430 | goto notfound; |
431 | default: |
432 | /* Something failed; just do a linear search. */ |
433 | break; |
434 | } |
435 | } |
436 | #endif /* UFS_DIRHASH */ |
437 | |
438 | if (nameiop != LOOKUP || results->ulr_diroff == 0 || |
439 | results->ulr_diroff >= dp->i_size) { |
440 | entryoffsetinblock = 0; |
441 | results->ulr_offset = 0; |
442 | numdirpasses = 1; |
443 | } else { |
444 | results->ulr_offset = results->ulr_diroff; |
445 | entryoffsetinblock = results->ulr_offset & bmask; |
446 | if (entryoffsetinblock != 0 && |
447 | (error = ufs_blkatoff(vdp, (off_t)results->ulr_offset, |
448 | NULL, &bp, false))) |
449 | goto out; |
450 | numdirpasses = 2; |
451 | namecache_count_2passes(); |
452 | } |
453 | prevoff = results->ulr_offset; |
454 | endsearch = roundup(dp->i_size, dirblksiz); |
455 | enduseful = 0; |
456 | |
457 | searchloop: |
458 | while (results->ulr_offset < endsearch) { |
459 | if (curcpu()->ci_schedstate.spc_flags & SPCF_SHOULDYIELD) |
460 | preempt(); |
461 | /* |
462 | * If necessary, get the next directory block. |
463 | */ |
464 | if ((results->ulr_offset & bmask) == 0) { |
465 | if (bp != NULL) |
466 | brelse(bp, 0); |
467 | error = ufs_blkatoff(vdp, (off_t)results->ulr_offset, |
468 | NULL, &bp, false); |
469 | if (error) |
470 | goto out; |
471 | entryoffsetinblock = 0; |
472 | } |
473 | /* |
474 | * If still looking for a slot, and at a DIRBLKSIZ |
475 | * boundary, have to start looking for free space again. |
476 | */ |
477 | if (slot.status == NONE && |
478 | (entryoffsetinblock & (dirblksiz - 1)) == 0) { |
479 | slot.offset = -1; |
480 | slot.freespace = 0; |
481 | } |
482 | /* |
483 | * Get pointer to next entry. |
484 | * Full validation checks are slow, so we only check |
485 | * enough to insure forward progress through the |
486 | * directory. Complete checks can be run by patching |
487 | * "dirchk" to be true. |
488 | */ |
489 | KASSERT(bp != NULL); |
490 | ep = (void *)((char *)bp->b_data + entryoffsetinblock); |
491 | const char *msg; |
492 | reclen = ufs_rw16(ep->d_reclen, needswap); |
493 | if ((reclen == 0 && (msg = "null entry" )) || (dirchk && |
494 | (msg = ufs_dirbadentry(vdp, ep, entryoffsetinblock)))) { |
495 | ufs_dirbad(dp, results->ulr_offset, msg); |
496 | reclen = dirblksiz - |
497 | (entryoffsetinblock & (dirblksiz - 1)); |
498 | goto next; |
499 | } |
500 | |
501 | /* |
502 | * If an appropriate sized slot has not yet been found, |
503 | * check to see if one is available. Also accumulate space |
504 | * in the current block so that we can determine if |
505 | * compaction is viable. |
506 | */ |
507 | if (slot.status != FOUND) { |
508 | int size = reclen; |
509 | if (ep->d_ino != 0) |
510 | size -= UFS_DIRSIZ(fsfmt, ep, needswap); |
511 | if (size > 0) |
512 | slot_update(&slot, size, reclen, |
513 | results->ulr_offset); |
514 | } |
515 | |
516 | if (ep->d_ino == 0) |
517 | goto next; |
518 | |
519 | /* |
520 | * Check for a name match. |
521 | */ |
522 | const uint16_t namlen = NAMLEN(fsfmt, needswap, ep); |
523 | if (namlen != cnp->cn_namelen || |
524 | memcmp(cnp->cn_nameptr, ep->d_name, (size_t)namlen)) |
525 | goto next; |
526 | |
527 | #ifdef UFS_DIRHASH |
528 | foundentry: |
529 | #endif |
530 | /* |
531 | * Save directory entry's inode number and |
532 | * reclen, and release directory buffer. |
533 | */ |
534 | if (!fsfmt && ep->d_type == DT_WHT) { |
535 | slot_white(&slot, reclen, results); |
536 | /* |
537 | * This is used to set results->ulr_endoff, which may |
538 | * be used by ufs_direnter() as a length to truncate |
539 | * the directory to. Therefore, it must point past the |
540 | * end of the last non-empty directory entry. We don't |
541 | * know where that is in this case, so we effectively |
542 | * disable shrinking by using the existing size of the |
543 | * directory. |
544 | * |
545 | * Note that we wouldn't expect to shrink the |
546 | * directory while rewriting an existing entry anyway. |
547 | */ |
548 | enduseful = endsearch; |
549 | cnp->cn_flags |= ISWHITEOUT; |
550 | numdirpasses--; |
551 | goto notfound; |
552 | } |
553 | foundino = ufs_rw32(ep->d_ino, needswap); |
554 | results->ulr_reclen = reclen; |
555 | goto found; |
556 | next: |
557 | prevoff = results->ulr_offset; |
558 | results->ulr_offset += reclen; |
559 | entryoffsetinblock += reclen; |
560 | if (ep->d_ino) |
561 | enduseful = results->ulr_offset; |
562 | } |
563 | notfound: |
564 | /* |
565 | * If we started in the middle of the directory and failed |
566 | * to find our target, we must check the beginning as well. |
567 | */ |
568 | if (numdirpasses == 2) { |
569 | numdirpasses--; |
570 | results->ulr_offset = 0; |
571 | endsearch = results->ulr_diroff; |
572 | goto searchloop; |
573 | } |
574 | if (bp != NULL) |
575 | brelse(bp, 0); |
576 | /* |
577 | * If creating, and at end of pathname and current |
578 | * directory has not been removed, then can consider |
579 | * allowing file to be created. |
580 | */ |
581 | if ((nameiop == CREATE || nameiop == RENAME || |
582 | (nameiop == DELETE && |
583 | (cnp->cn_flags & DOWHITEOUT) && |
584 | (cnp->cn_flags & ISWHITEOUT))) && |
585 | (flags & ISLASTCN) && dp->i_nlink != 0) { |
586 | /* |
587 | * Access for write is interpreted as allowing |
588 | * creation of files in the directory. |
589 | */ |
590 | error = VOP_ACCESS(vdp, VWRITE, cred); |
591 | if (error) |
592 | goto out; |
593 | error = slot_estimate(&slot, dirblksiz, nameiop, |
594 | prevoff, enduseful, dp, results); |
595 | /* |
596 | * We return with the directory locked, so that |
597 | * the parameters we set up above will still be |
598 | * valid if we actually decide to do a direnter(). |
599 | * We return ni_vp == NULL to indicate that the entry |
600 | * does not currently exist; we leave a pointer to |
601 | * the (locked) directory inode in ndp->ni_dvp. |
602 | * |
603 | * NB - if the directory is unlocked, then this |
604 | * information cannot be used. |
605 | */ |
606 | goto out; |
607 | } |
608 | /* |
609 | * Insert name into cache (as non-existent) if appropriate. |
610 | */ |
611 | if (nameiop != CREATE) { |
612 | cache_enter(vdp, *vpp, cnp->cn_nameptr, cnp->cn_namelen, |
613 | cnp->cn_flags); |
614 | } |
615 | error = ENOENT; |
616 | goto out; |
617 | |
618 | found: |
619 | if (numdirpasses == 2) |
620 | namecache_count_pass2(); |
621 | /* |
622 | * Check that directory length properly reflects presence |
623 | * of this entry. |
624 | */ |
625 | const uint64_t newisize = |
626 | results->ulr_offset + UFS_DIRSIZ(fsfmt, ep, needswap); |
627 | if (newisize > dp->i_size) { |
628 | ufs_dirbad(dp, results->ulr_offset, "i_size too small" ); |
629 | dp->i_size = newisize; |
630 | DIP_ASSIGN(dp, size, dp->i_size); |
631 | dp->i_flag |= IN_CHANGE | IN_UPDATE; |
632 | UFS_WAPBL_UPDATE(vdp, NULL, NULL, UPDATE_DIROP); |
633 | } |
634 | brelse(bp, 0); |
635 | |
636 | /* |
637 | * Found component in pathname. |
638 | * If the final component of path name, save information |
639 | * in the cache as to where the entry was found. |
640 | */ |
641 | if ((flags & ISLASTCN) && nameiop == LOOKUP) |
642 | results->ulr_diroff = results->ulr_offset & ~(dirblksiz - 1); |
643 | |
644 | /* |
645 | * If deleting, and at end of pathname, return |
646 | * parameters which can be used to remove file. |
647 | * Lock the inode, being careful with ".". |
648 | */ |
649 | if (nameiop == DELETE && (flags & ISLASTCN)) { |
650 | /* |
651 | * Return pointer to current entry in results->ulr_offset, |
652 | * and distance past previous entry (if there |
653 | * is a previous entry in this block) in results->ulr_count. |
654 | * Save directory inode pointer in ndp->ni_dvp for dirremove(). |
655 | */ |
656 | calc_count(results, dirblksiz, prevoff); |
657 | |
658 | if ((error = ufs_getino(vdp, dp, foundino, &tdp, false)) != 0) |
659 | goto out; |
660 | |
661 | if ((error = ufs_can_delete(tdp, vdp, dp, cred)) != 0) |
662 | goto out; |
663 | |
664 | *vpp = tdp; |
665 | goto out; |
666 | } |
667 | |
668 | /* |
669 | * If rewriting (RENAME), return the inode and the |
670 | * information required to rewrite the present directory |
671 | * Must get inode of directory entry to verify it's a |
672 | * regular file, or empty directory. |
673 | */ |
674 | if (nameiop == RENAME && (flags & ISLASTCN)) { |
675 | if ((error = VOP_ACCESS(vdp, VWRITE, cred)) != 0) |
676 | goto out; |
677 | /* |
678 | * Careful about locking second inode. |
679 | * This can only occur if the target is ".". |
680 | */ |
681 | if ((error = ufs_getino(vdp, dp, foundino, &tdp, true)) != 0) |
682 | goto out; |
683 | *vpp = tdp; |
684 | goto out; |
685 | } |
686 | |
687 | if ((error = ufs_getino(vdp, dp, foundino, &tdp, false)) != 0) |
688 | goto out; |
689 | |
690 | *vpp = tdp; |
691 | /* |
692 | * Insert name into cache if appropriate. |
693 | */ |
694 | cache_enter(vdp, *vpp, cnp->cn_nameptr, cnp->cn_namelen, cnp->cn_flags); |
695 | error = 0; |
696 | |
697 | out: |
698 | fstrans_done(vdp->v_mount); |
699 | return error; |
700 | } |
701 | |
702 | void |
703 | ufs_dirbad(struct inode *ip, doff_t offset, const char *how) |
704 | { |
705 | struct mount *mp = ITOV(ip)->v_mount; |
706 | void (*p)(const char *, ...) __printflike(1, 2) = |
707 | (mp->mnt_flag & MNT_RDONLY) == 0 ? panic : printf; |
708 | |
709 | (*p)("%s: bad dir ino %ju at offset %d: %s\n" , |
710 | mp->mnt_stat.f_mntonname, (uintmax_t)ip->i_number, |
711 | offset, how); |
712 | } |
713 | |
714 | /* |
715 | * Do consistency checking on a directory entry: |
716 | * record length must be multiple of 4 |
717 | * entry must fit in rest of its DIRBLKSIZ block |
718 | * record must be large enough to contain entry |
719 | * name is not longer than FFS_MAXNAMLEN |
720 | * name must be as long as advertised, and null terminated |
721 | */ |
722 | const char * |
723 | ufs_dirbadentry(const struct vnode *dp, const struct direct *ep, |
724 | int entryoffsetinblock) |
725 | { |
726 | const struct ufsmount *ump = VFSTOUFS(dp->v_mount); |
727 | const int needswap = UFS_MPNEEDSWAP(ump); |
728 | const int dirblksiz = ump->um_dirblksiz; |
729 | const int maxsize = dirblksiz - (entryoffsetinblock & (dirblksiz - 1)); |
730 | const int fsfmt = FSFMT(dp); |
731 | const uint8_t namlen = NAMLEN(fsfmt, needswap, ep); |
732 | const uint16_t reclen = ufs_rw16(ep->d_reclen, needswap); |
733 | const int dirsiz = (int)UFS_DIRSIZ(fsfmt, ep, needswap); |
734 | const char *name = ep->d_name; |
735 | const char *str; |
736 | #ifdef DIAGNOSTIC |
737 | static char buf[512]; |
738 | #endif |
739 | |
740 | if ((reclen & 0x3) != 0) |
741 | str = "not rounded" ; |
742 | else if (reclen > maxsize) |
743 | str = "too big" ; |
744 | else if (reclen < dirsiz) |
745 | str = "too small" ; |
746 | #if FFS_MAXNAMLEN < 255 |
747 | else if (namlen > FFS_MAXNAMLEN) |
748 | str = "long name" ; |
749 | #endif |
750 | else |
751 | str = NULL; |
752 | |
753 | if (str) { |
754 | #ifdef DIAGNOSTIC |
755 | snprintf(buf, sizeof(buf), "Bad dir (%s), reclen=%#x, " |
756 | "namlen=%d, dirsiz=%d <= reclen=%d <= maxsize=%d, " |
757 | "flags=%#x, entryoffsetinblock=%d, dirblksiz=%d" , |
758 | str, reclen, namlen, dirsiz, reclen, maxsize, |
759 | dp->v_mount->mnt_flag, entryoffsetinblock, dirblksiz); |
760 | str = buf; |
761 | #endif |
762 | return str; |
763 | } |
764 | |
765 | if (ep->d_ino == 0) |
766 | return NULL; |
767 | |
768 | for (uint8_t i = 0; i < namlen; i++) |
769 | if (name[i] == '\0') { |
770 | str = "NUL in name" ; |
771 | #ifdef DIAGNOSTIC |
772 | snprintf(buf, sizeof(buf), "%s [%s] i=%d, namlen=%d" , |
773 | str, name, i, namlen); |
774 | str = buf; |
775 | #endif |
776 | return str; |
777 | } |
778 | |
779 | if (name[namlen]) { |
780 | str = "missing NUL in name" ; |
781 | #ifdef DIAGNOSTIC |
782 | snprintf(buf, sizeof(buf), "%s [%*.*s] namlen=%d" , str, |
783 | namlen, namlen, name, namlen); |
784 | str = buf; |
785 | #endif |
786 | return str; |
787 | } |
788 | return NULL; |
789 | } |
790 | |
791 | /* |
792 | * Construct a new directory entry after a call to namei, using the |
793 | * name in the componentname argument cnp. The argument ip is the |
794 | * inode to which the new directory entry will refer. |
795 | */ |
796 | void |
797 | ufs_makedirentry(struct inode *ip, struct componentname *cnp, |
798 | struct direct *newdirp) |
799 | { |
800 | newdirp->d_ino = ip->i_number; |
801 | newdirp->d_namlen = cnp->cn_namelen; |
802 | memcpy(newdirp->d_name, cnp->cn_nameptr, (size_t)cnp->cn_namelen); |
803 | newdirp->d_name[cnp->cn_namelen] = '\0'; |
804 | if (FSFMT(ITOV(ip))) |
805 | newdirp->d_type = 0; |
806 | else |
807 | newdirp->d_type = IFTODT(ip->i_mode); |
808 | } |
809 | |
810 | |
811 | static int |
812 | ufs_dirgrow(struct vnode *dvp, const struct ufs_lookup_results *ulr, |
813 | struct vnode *tvp, struct direct *dirp, |
814 | struct componentname *cnp, struct buf *newdirbp) |
815 | { |
816 | const kauth_cred_t cr = cnp->cn_cred; |
817 | const struct ufsmount *ump = VFSTOUFS(dvp->v_mount); |
818 | const int needswap = UFS_MPNEEDSWAP(ump); |
819 | const int dirblksiz = ump->um_dirblksiz; |
820 | const int fsfmt = FSFMT(dvp); |
821 | const u_int newentrysize = UFS_DIRSIZ(0, dirp, 0); |
822 | struct inode *dp = VTOI(dvp); |
823 | int error, ret, blkoff; |
824 | struct timespec ts; |
825 | struct buf *bp; |
826 | |
827 | /* |
828 | * If ulr_count is 0, then namei could find no |
829 | * space in the directory. Here, ulr_offset will |
830 | * be on a directory block boundary and we will write the |
831 | * new entry into a fresh block. |
832 | */ |
833 | if (ulr->ulr_offset & (dirblksiz - 1)) |
834 | panic("%s: newblk" , __func__); |
835 | if ((error = UFS_BALLOC(dvp, (off_t)ulr->ulr_offset, dirblksiz, |
836 | cr, B_CLRBUF | B_SYNC, &bp)) != 0) { |
837 | return error; |
838 | } |
839 | |
840 | dp->i_size = ulr->ulr_offset + dirblksiz; |
841 | DIP_ASSIGN(dp, size, dp->i_size); |
842 | dp->i_flag |= IN_CHANGE | IN_UPDATE; |
843 | uvm_vnp_setsize(dvp, dp->i_size); |
844 | dirp->d_reclen = ufs_rw16(dirblksiz, needswap); |
845 | dirp->d_ino = ufs_rw32(dirp->d_ino, needswap); |
846 | if (fsfmt && ENDIANSWAP(needswap)) |
847 | ufs_dirswap(dirp); |
848 | blkoff = ulr->ulr_offset & (ump->um_mountp->mnt_stat.f_iosize - 1); |
849 | memcpy((char *)bp->b_data + blkoff, dirp, newentrysize); |
850 | #ifdef UFS_DIRHASH |
851 | if (dp->i_dirhash != NULL) { |
852 | ufsdirhash_newblk(dp, ulr->ulr_offset); |
853 | ufsdirhash_add(dp, dirp, ulr->ulr_offset); |
854 | ufsdirhash_checkblock(dp, (char *)bp->b_data + blkoff, |
855 | ulr->ulr_offset); |
856 | } |
857 | #endif |
858 | error = VOP_BWRITE(bp->b_vp, bp); |
859 | vfs_timestamp(&ts); |
860 | ret = UFS_UPDATE(dvp, &ts, &ts, UPDATE_DIROP); |
861 | if (error == 0) |
862 | return ret; |
863 | return error; |
864 | } |
865 | |
866 | static int |
867 | #if __GNUC_PREREQ__(5, 3) |
868 | /* This gets miscompiled by gcc 5.3 PR/51094 */ |
869 | __attribute__((__optimize__("no-tree-vrp" ))) |
870 | #endif |
871 | ufs_dircompact(struct vnode *dvp, const struct ufs_lookup_results *ulr, |
872 | struct vnode *tvp, struct direct *dirp, |
873 | struct componentname *cnp, struct buf *newdirbp) |
874 | { |
875 | const struct ufsmount *ump = VFSTOUFS(dvp->v_mount); |
876 | const int needswap = UFS_MPNEEDSWAP(ump); |
877 | const int fsfmt = FSFMT(dvp); |
878 | const u_int newentrysize = UFS_DIRSIZ(0, dirp, 0); |
879 | struct inode *dp = VTOI(dvp); |
880 | struct buf *bp; |
881 | u_int dsize; |
882 | struct direct *ep, *nep; |
883 | int error, loc, spacefree; |
884 | char *dirbuf; |
885 | uint16_t reclen; |
886 | |
887 | UFS_WAPBL_JLOCK_ASSERT(dvp->v_mount); |
888 | |
889 | /* |
890 | * If ulr_count is non-zero, then namei found space for the new |
891 | * entry in the range ulr_offset to ulr_offset + ulr_count |
892 | * in the directory. To use this space, we may have to compact |
893 | * the entries located there, by copying them together towards the |
894 | * beginning of the block, leaving the free space in one usable |
895 | * chunk at the end. |
896 | */ |
897 | |
898 | /* |
899 | * Increase size of directory if entry eats into new space. |
900 | * This should never push the size past a new multiple of |
901 | * DIRBLKSIZ. |
902 | * |
903 | * N.B. - THIS IS AN ARTIFACT OF 4.2 AND SHOULD NEVER HAPPEN. |
904 | */ |
905 | if (ulr->ulr_offset + ulr->ulr_count > dp->i_size) { |
906 | #ifdef DIAGNOSTIC |
907 | printf("%s: reached 4.2-only block, not supposed to happen\n" , |
908 | __func__); |
909 | #endif |
910 | dp->i_size = ulr->ulr_offset + ulr->ulr_count; |
911 | DIP_ASSIGN(dp, size, dp->i_size); |
912 | dp->i_flag |= IN_CHANGE | IN_UPDATE; |
913 | UFS_WAPBL_UPDATE(dvp, NULL, NULL, UPDATE_DIROP); |
914 | } |
915 | /* |
916 | * Get the block containing the space for the new directory entry. |
917 | */ |
918 | error = ufs_blkatoff(dvp, (off_t)ulr->ulr_offset, &dirbuf, &bp, true); |
919 | if (error) |
920 | return error; |
921 | |
922 | /* |
923 | * Find space for the new entry. In the simple case, the entry at |
924 | * offset base will have the space. If it does not, then namei |
925 | * arranged that compacting the region ulr_offset to |
926 | * ulr_offset + ulr_count would yield the space. |
927 | */ |
928 | ep = (void *)dirbuf; |
929 | dsize = (ep->d_ino != 0) ? UFS_DIRSIZ(fsfmt, ep, needswap) : 0; |
930 | reclen = ufs_rw16(ep->d_reclen, needswap); |
931 | spacefree = reclen - dsize; |
932 | for (loc = reclen; loc < ulr->ulr_count; ) { |
933 | nep = (void *)(dirbuf + loc); |
934 | |
935 | /* Trim the existing slot (NB: dsize may be zero). */ |
936 | ep->d_reclen = ufs_rw16(dsize, needswap); |
937 | ep = (void *)((char *)ep + dsize); |
938 | |
939 | reclen = ufs_rw16(nep->d_reclen, needswap); |
940 | loc += reclen; |
941 | if (nep->d_ino == 0) { |
942 | /* |
943 | * A mid-block unused entry. Such entries are |
944 | * never created by the kernel, but fsck_ffs |
945 | * can create them (and it doesn't fix them). |
946 | * |
947 | * Add up the free space, and initialise the |
948 | * relocated entry since we don't memcpy it. |
949 | */ |
950 | spacefree += reclen; |
951 | ep->d_ino = 0; |
952 | dsize = 0; |
953 | continue; |
954 | } |
955 | dsize = UFS_DIRSIZ(fsfmt, nep, needswap); |
956 | spacefree += reclen - dsize; |
957 | #ifdef UFS_DIRHASH |
958 | if (dp->i_dirhash != NULL) |
959 | ufsdirhash_move(dp, nep, |
960 | ulr->ulr_offset + ((char *)nep - dirbuf), |
961 | ulr->ulr_offset + ((char *)ep - dirbuf)); |
962 | #endif |
963 | memcpy(ep, nep, dsize); |
964 | } |
965 | /* |
966 | * Here, `ep' points to a directory entry containing `dsize' in-use |
967 | * bytes followed by `spacefree' unused bytes. If ep->d_ino == 0, |
968 | * then the entry is completely unused (dsize == 0). The value |
969 | * of ep->d_reclen is always indeterminate. |
970 | * |
971 | * Update the pointer fields in the previous entry (if any), |
972 | * copy in the new entry, and write out the block. |
973 | */ |
974 | if (ep->d_ino == 0 || |
975 | (ufs_rw32(ep->d_ino, needswap) == UFS_WINO && |
976 | memcmp(ep->d_name, dirp->d_name, dirp->d_namlen) == 0)) { |
977 | if (spacefree + dsize < newentrysize) |
978 | panic("%s: too big" , __func__); |
979 | dirp->d_reclen = spacefree + dsize; |
980 | } else { |
981 | if (spacefree < newentrysize) |
982 | panic("%s: nospace" , __func__); |
983 | dirp->d_reclen = spacefree; |
984 | ep->d_reclen = ufs_rw16(dsize, needswap); |
985 | ep = (void *)((char *)ep + dsize); |
986 | } |
987 | |
988 | dirp->d_reclen = ufs_rw16(dirp->d_reclen, needswap); |
989 | dirp->d_ino = ufs_rw32(dirp->d_ino, needswap); |
990 | if (fsfmt && ENDIANSWAP(needswap)) |
991 | ufs_dirswap(dirp); |
992 | #ifdef UFS_DIRHASH |
993 | if (dp->i_dirhash != NULL && (ep->d_ino == 0 || |
994 | dirp->d_reclen == spacefree)) |
995 | ufsdirhash_add(dp, dirp, ulr->ulr_offset + ((char *)ep - dirbuf)); |
996 | #endif |
997 | memcpy(ep, dirp, newentrysize); |
998 | #ifdef UFS_DIRHASH |
999 | if (dp->i_dirhash != NULL) { |
1000 | const int dirblkmsk = ump->um_dirblksiz - 1; |
1001 | ufsdirhash_checkblock(dp, dirbuf - |
1002 | (ulr->ulr_offset & dirblkmsk), |
1003 | ulr->ulr_offset & ~dirblkmsk); |
1004 | } |
1005 | #endif |
1006 | error = VOP_BWRITE(bp->b_vp, bp); |
1007 | dp->i_flag |= IN_CHANGE | IN_UPDATE; |
1008 | /* |
1009 | * If all went well, and the directory can be shortened, proceed |
1010 | * with the truncation. Note that we have to unlock the inode for |
1011 | * the entry that we just entered, as the truncation may need to |
1012 | * lock other inodes which can lead to deadlock if we also hold a |
1013 | * lock on the newly entered node. |
1014 | */ |
1015 | if (error == 0 && ulr->ulr_endoff && ulr->ulr_endoff < dp->i_size) { |
1016 | const kauth_cred_t cr = cnp->cn_cred; |
1017 | #ifdef UFS_DIRHASH |
1018 | if (dp->i_dirhash != NULL) |
1019 | ufsdirhash_dirtrunc(dp, ulr->ulr_endoff); |
1020 | #endif |
1021 | (void) UFS_TRUNCATE(dvp, (off_t)ulr->ulr_endoff, IO_SYNC, cr); |
1022 | } |
1023 | UFS_WAPBL_UPDATE(dvp, NULL, NULL, UPDATE_DIROP); |
1024 | return error; |
1025 | } |
1026 | |
1027 | /* |
1028 | * Write a directory entry after a call to namei, using the parameters |
1029 | * that ufs_lookup left in nameidata and in the ufs_lookup_results. |
1030 | * |
1031 | * DVP is the directory to be updated. It must be locked. |
1032 | * ULR is the ufs_lookup_results structure from the final lookup step. |
1033 | * TVP is not used. (XXX: why is it here? remove it) |
1034 | * DIRP is the new directory entry contents. |
1035 | * CNP is the componentname from the final lookup step. |
1036 | * NEWDIRBP is not used and (XXX) should be removed. The previous |
1037 | * comment here said it was used by the now-removed softupdates code. |
1038 | * |
1039 | * The link count of the target inode is *not* incremented; the |
1040 | * caller does that. |
1041 | * |
1042 | * If ulr->ulr_count is 0, ufs_lookup did not find space to insert the |
1043 | * directory entry. ulr_offset, which is the place to put the entry, |
1044 | * should be on a block boundary (and should be at the end of the |
1045 | * directory AFAIK) and a fresh block is allocated to put the new |
1046 | * directory entry in. |
1047 | * |
1048 | * If ulr->ulr_count is not zero, ufs_lookup found a slot to insert |
1049 | * the entry into. This slot ranges from ulr_offset to ulr_offset + |
1050 | * ulr_count. However, this slot may already be partially populated |
1051 | * requiring compaction. See notes below. |
1052 | * |
1053 | * Furthermore, if ulr_count is not zero and ulr_endoff is not the |
1054 | * same as i_size, the directory is truncated to size ulr_endoff. |
1055 | */ |
1056 | int |
1057 | ufs_direnter(struct vnode *dvp, const struct ufs_lookup_results *ulr, |
1058 | struct vnode *tvp, struct direct *dirp, |
1059 | struct componentname *cnp, struct buf *newdirbp) |
1060 | { |
1061 | if (ulr->ulr_count == 0) |
1062 | return ufs_dirgrow(dvp, ulr, tvp, dirp, cnp, newdirbp); |
1063 | else |
1064 | return ufs_dircompact(dvp, ulr, tvp, dirp, cnp, newdirbp); |
1065 | } |
1066 | |
1067 | /* |
1068 | * Remove a directory entry after a call to namei, using the |
1069 | * parameters that ufs_lookup left in nameidata and in the |
1070 | * ufs_lookup_results. |
1071 | * |
1072 | * DVP is the directory to be updated. It must be locked. |
1073 | * ULR is the ufs_lookup_results structure from the final lookup step. |
1074 | * IP, if not null, is the inode being unlinked. |
1075 | * FLAGS may contain DOWHITEOUT. |
1076 | * ISRMDIR is not used and (XXX) should be removed. |
1077 | * |
1078 | * If FLAGS contains DOWHITEOUT the entry is replaced with a whiteout |
1079 | * instead of being cleared. |
1080 | * |
1081 | * ulr->ulr_offset contains the position of the directory entry |
1082 | * to be removed. |
1083 | * |
1084 | * ulr->ulr_reclen contains the size of the directory entry to be |
1085 | * removed. |
1086 | * |
1087 | * ulr->ulr_count contains the size of the *previous* directory |
1088 | * entry. This allows finding it, for free space management. If |
1089 | * ulr_count is 0, the target entry is at the beginning of the |
1090 | * directory. (Does this ever happen? The first entry should be ".", |
1091 | * which should only be removed at rmdir time. Does rmdir come here |
1092 | * to clear out the "." and ".." entries? Perhaps, but I doubt it.) |
1093 | * |
1094 | * The space is marked free by adding it to the record length (not |
1095 | * name length) of the preceding entry. If the first entry becomes |
1096 | * free, it is marked free by setting the inode number to 0. |
1097 | * |
1098 | * The link count of IP is decremented. Note that this is not the |
1099 | * inverse behavior of ufs_direnter, which does not adjust link |
1100 | * counts. Sigh. |
1101 | */ |
1102 | int |
1103 | ufs_dirremove(struct vnode *dvp, const struct ufs_lookup_results *ulr, |
1104 | struct inode *ip, int flags, int isrmdir) |
1105 | { |
1106 | struct inode *dp = VTOI(dvp); |
1107 | struct direct *ep; |
1108 | struct buf *bp; |
1109 | int error; |
1110 | const int needswap = UFS_MPNEEDSWAP(dp->i_ump); |
1111 | uint16_t reclen; |
1112 | |
1113 | UFS_WAPBL_JLOCK_ASSERT(dvp->v_mount); |
1114 | |
1115 | if (flags & DOWHITEOUT) { |
1116 | /* |
1117 | * Whiteout entry: set d_ino to UFS_WINO. |
1118 | */ |
1119 | error = ufs_blkatoff(dvp, (off_t)ulr->ulr_offset, &ep, |
1120 | &bp, true); |
1121 | if (error) |
1122 | return (error); |
1123 | ep->d_ino = ufs_rw32(UFS_WINO, needswap); |
1124 | ep->d_type = DT_WHT; |
1125 | goto out; |
1126 | } |
1127 | |
1128 | if ((error = ufs_blkatoff(dvp, |
1129 | (off_t)(ulr->ulr_offset - ulr->ulr_count), &ep, &bp, true)) != 0) |
1130 | return (error); |
1131 | |
1132 | reclen = ufs_rw16(ep->d_reclen, needswap); |
1133 | #ifdef UFS_DIRHASH |
1134 | /* |
1135 | * Remove the dirhash entry. This is complicated by the fact |
1136 | * that `ep' is the previous entry when ulr_count != 0. |
1137 | */ |
1138 | if (dp->i_dirhash != NULL) |
1139 | ufsdirhash_remove(dp, (ulr->ulr_count == 0) ? ep : |
1140 | (void *)((char *)ep + reclen), ulr->ulr_offset); |
1141 | #endif |
1142 | |
1143 | if (ulr->ulr_count == 0) { |
1144 | /* |
1145 | * First entry in block: set d_ino to zero. |
1146 | */ |
1147 | ep->d_ino = 0; |
1148 | } else { |
1149 | /* |
1150 | * Collapse new free space into previous entry. |
1151 | */ |
1152 | ep->d_reclen = ufs_rw16(reclen + ulr->ulr_reclen, needswap); |
1153 | } |
1154 | |
1155 | #ifdef UFS_DIRHASH |
1156 | if (dp->i_dirhash != NULL) { |
1157 | int dirblksiz = ip->i_ump->um_dirblksiz; |
1158 | ufsdirhash_checkblock(dp, (char *)ep - |
1159 | ((ulr->ulr_offset - ulr->ulr_count) & (dirblksiz - 1)), |
1160 | ulr->ulr_offset & ~(dirblksiz - 1)); |
1161 | } |
1162 | #endif |
1163 | |
1164 | out: |
1165 | if (ip) { |
1166 | ip->i_nlink--; |
1167 | DIP_ASSIGN(ip, nlink, ip->i_nlink); |
1168 | ip->i_flag |= IN_CHANGE; |
1169 | UFS_WAPBL_UPDATE(ITOV(ip), NULL, NULL, 0); |
1170 | } |
1171 | /* |
1172 | * XXX did it ever occur to anyone that it might be a good |
1173 | * idea to restore ip->i_nlink if this fails? Or something? |
1174 | * Currently on error return from this function the state of |
1175 | * ip->i_nlink depends on what happened, and callers |
1176 | * definitely do not take this into account. |
1177 | */ |
1178 | error = VOP_BWRITE(bp->b_vp, bp); |
1179 | dp->i_flag |= IN_CHANGE | IN_UPDATE; |
1180 | /* |
1181 | * If the last named reference to a snapshot goes away, |
1182 | * drop its snapshot reference so that it will be reclaimed |
1183 | * when last open reference goes away. |
1184 | */ |
1185 | if (ip != 0 && (ip->i_flags & SF_SNAPSHOT) != 0 && |
1186 | ip->i_nlink == 0) |
1187 | UFS_SNAPGONE(ITOV(ip)); |
1188 | UFS_WAPBL_UPDATE(dvp, NULL, NULL, 0); |
1189 | return (error); |
1190 | } |
1191 | |
1192 | /* |
1193 | * Rewrite an existing directory entry to point at the inode supplied. |
1194 | * |
1195 | * DP is the directory to update. |
1196 | * OFFSET is the position of the entry in question. It may come |
1197 | * from ulr_offset of a ufs_lookup_results. |
1198 | * OIP is the old inode the directory previously pointed to. |
1199 | * NEWINUM is the number of the new inode. |
1200 | * NEWTYPE is the new value for the type field of the directory entry. |
1201 | * (This is ignored if the fs doesn't support that.) |
1202 | * ISRMDIR is not used and (XXX) should be removed. |
1203 | * IFLAGS are added to DP's inode flags. |
1204 | * |
1205 | * The link count of OIP is decremented. Note that the link count of |
1206 | * the new inode is *not* incremented. Yay for symmetry. |
1207 | */ |
1208 | int |
1209 | ufs_dirrewrite(struct inode *dp, off_t offset, |
1210 | struct inode *oip, ino_t newinum, int newtype, |
1211 | int isrmdir, int iflags) |
1212 | { |
1213 | struct buf *bp; |
1214 | struct direct *ep; |
1215 | struct vnode *vdp = ITOV(dp); |
1216 | int error; |
1217 | |
1218 | error = ufs_blkatoff(vdp, offset, &ep, &bp, true); |
1219 | if (error) |
1220 | return (error); |
1221 | ep->d_ino = ufs_rw32(newinum, UFS_MPNEEDSWAP(dp->i_ump)); |
1222 | if (!FSFMT(vdp)) |
1223 | ep->d_type = newtype; |
1224 | oip->i_nlink--; |
1225 | DIP_ASSIGN(oip, nlink, oip->i_nlink); |
1226 | oip->i_flag |= IN_CHANGE; |
1227 | UFS_WAPBL_UPDATE(ITOV(oip), NULL, NULL, UPDATE_DIROP); |
1228 | error = VOP_BWRITE(bp->b_vp, bp); |
1229 | dp->i_flag |= iflags; |
1230 | /* |
1231 | * If the last named reference to a snapshot goes away, |
1232 | * drop its snapshot reference so that it will be reclaimed |
1233 | * when last open reference goes away. |
1234 | */ |
1235 | if ((oip->i_flags & SF_SNAPSHOT) != 0 && oip->i_nlink == 0) |
1236 | UFS_SNAPGONE(ITOV(oip)); |
1237 | UFS_WAPBL_UPDATE(vdp, NULL, NULL, UPDATE_DIROP); |
1238 | return (error); |
1239 | } |
1240 | |
1241 | /* |
1242 | * Check if a directory is empty or not. |
1243 | * Inode supplied must be locked. |
1244 | * |
1245 | * Using a struct dirtemplate here is not precisely |
1246 | * what we want, but better than using a struct direct. |
1247 | * |
1248 | * NB: does not handle corrupted directories. |
1249 | */ |
1250 | int |
1251 | ufs_dirempty(struct inode *ip, ino_t parentino, kauth_cred_t cred) |
1252 | { |
1253 | doff_t off; |
1254 | struct dirtemplate dbuf; |
1255 | struct direct *dp = (void *)&dbuf; |
1256 | int error; |
1257 | size_t count; |
1258 | const int needswap = UFS_IPNEEDSWAP(ip); |
1259 | const int fsfmt = FSFMT(ITOV(ip)); |
1260 | #define MINDIRSIZ (sizeof (struct dirtemplate) / 2) |
1261 | |
1262 | for (off = 0; off < ip->i_size; |
1263 | off += ufs_rw16(dp->d_reclen, needswap)) { |
1264 | error = ufs_bufio(UIO_READ, ITOV(ip), dp, MINDIRSIZ, |
1265 | off, IO_NODELOCKED, cred, &count, NULL); |
1266 | /* |
1267 | * Since we read MINDIRSIZ, residual must |
1268 | * be 0 unless we're at end of file. |
1269 | */ |
1270 | if (error || count != 0) |
1271 | return (0); |
1272 | /* avoid infinite loops */ |
1273 | if (dp->d_reclen == 0) |
1274 | return (0); |
1275 | /* skip empty entries */ |
1276 | ino_t ino = ufs_rw32(dp->d_ino, needswap); |
1277 | if (ino == 0 || ino == UFS_WINO) |
1278 | continue; |
1279 | /* accept only "." and ".." */ |
1280 | const uint8_t namlen = NAMLEN(fsfmt, needswap, dp); |
1281 | if (namlen > 2) |
1282 | return (0); |
1283 | if (dp->d_name[0] != '.') |
1284 | return (0); |
1285 | /* |
1286 | * At this point namlen must be 1 or 2. |
1287 | * 1 implies ".", 2 implies ".." if second |
1288 | * char is also "." |
1289 | */ |
1290 | if (namlen == 1 && ino == ip->i_number) |
1291 | continue; |
1292 | if (dp->d_name[1] == '.' && ino == parentino) |
1293 | continue; |
1294 | return (0); |
1295 | } |
1296 | return (1); |
1297 | } |
1298 | |
1299 | #define UFS_DIRRABLKS 0 |
1300 | int ufs_dirrablks = UFS_DIRRABLKS; |
1301 | |
1302 | /* |
1303 | * ufs_blkatoff: Return buffer with the contents of block "offset" from |
1304 | * the beginning of directory "vp". If "res" is non-NULL, fill it in with |
1305 | * a pointer to the remaining space in the directory. If the caller intends |
1306 | * to modify the buffer returned, "modify" must be true. |
1307 | */ |
1308 | |
1309 | int |
1310 | ufs_blkatoff(struct vnode *vp, off_t offset, void *v, struct buf **bpp, |
1311 | bool modify) |
1312 | { |
1313 | char **res = v; |
1314 | struct inode *ip __diagused; |
1315 | struct buf *bp; |
1316 | daddr_t lbn; |
1317 | const int dirrablks = ufs_dirrablks; |
1318 | daddr_t *blks; |
1319 | int *blksizes; |
1320 | int run, error; |
1321 | struct mount *mp = vp->v_mount; |
1322 | const int bshift = mp->mnt_fs_bshift; |
1323 | const int bsize = 1 << bshift; |
1324 | off_t eof; |
1325 | |
1326 | blks = kmem_alloc((1 + dirrablks) * sizeof(daddr_t), KM_SLEEP); |
1327 | blksizes = kmem_alloc((1 + dirrablks) * sizeof(int), KM_SLEEP); |
1328 | ip = VTOI(vp); |
1329 | KASSERT(vp->v_size == ip->i_size); |
1330 | GOP_SIZE(vp, vp->v_size, &eof, 0); |
1331 | lbn = offset >> bshift; |
1332 | |
1333 | for (run = 0; run <= dirrablks;) { |
1334 | const off_t curoff = lbn << bshift; |
1335 | const int size = MIN(eof - curoff, bsize); |
1336 | |
1337 | if (size == 0) { |
1338 | break; |
1339 | } |
1340 | KASSERT(curoff < eof); |
1341 | blks[run] = lbn; |
1342 | blksizes[run] = size; |
1343 | lbn++; |
1344 | run++; |
1345 | if (size != bsize) { |
1346 | break; |
1347 | } |
1348 | } |
1349 | KASSERT(run >= 1); |
1350 | error = breadn(vp, blks[0], blksizes[0], &blks[1], &blksizes[1], |
1351 | run - 1, (modify ? B_MODIFY : 0), &bp); |
1352 | if (error != 0) { |
1353 | *bpp = NULL; |
1354 | goto out; |
1355 | } |
1356 | if (res) { |
1357 | *res = (char *)bp->b_data + (offset & (bsize - 1)); |
1358 | } |
1359 | *bpp = bp; |
1360 | |
1361 | out: |
1362 | kmem_free(blks, (1 + dirrablks) * sizeof(daddr_t)); |
1363 | kmem_free(blksizes, (1 + dirrablks) * sizeof(int)); |
1364 | return error; |
1365 | } |
1366 | |