1 | /* $NetBSD: ulfs_lookup.c,v 1.39 2016/06/20 02:25:03 dholland Exp $ */ |
2 | /* from NetBSD: ufs_lookup.c,v 1.135 2015/07/11 11:04:48 mlelstv */ |
3 | |
4 | /* |
5 | * Copyright (c) 1989, 1993 |
6 | * The Regents of the University of California. All rights reserved. |
7 | * (c) UNIX System Laboratories, Inc. |
8 | * All or some portions of this file are derived from material licensed |
9 | * to the University of California by American Telephone and Telegraph |
10 | * Co. or Unix System Laboratories, Inc. and are reproduced herein with |
11 | * the permission of UNIX System Laboratories, Inc. |
12 | * |
13 | * Redistribution and use in source and binary forms, with or without |
14 | * modification, are permitted provided that the following conditions |
15 | * are met: |
16 | * 1. Redistributions of source code must retain the above copyright |
17 | * notice, this list of conditions and the following disclaimer. |
18 | * 2. Redistributions in binary form must reproduce the above copyright |
19 | * notice, this list of conditions and the following disclaimer in the |
20 | * documentation and/or other materials provided with the distribution. |
21 | * 3. Neither the name of the University nor the names of its contributors |
22 | * may be used to endorse or promote products derived from this software |
23 | * without specific prior written permission. |
24 | * |
25 | * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND |
26 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
27 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
28 | * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE |
29 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
30 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS |
31 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
32 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
33 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY |
34 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
35 | * SUCH DAMAGE. |
36 | * |
37 | * @(#)ufs_lookup.c 8.9 (Berkeley) 8/11/94 |
38 | */ |
39 | |
40 | #include <sys/cdefs.h> |
41 | __KERNEL_RCSID(0, "$NetBSD: ulfs_lookup.c,v 1.39 2016/06/20 02:25:03 dholland Exp $" ); |
42 | |
43 | #ifdef _KERNEL_OPT |
44 | #include "opt_lfs.h" |
45 | #endif |
46 | |
47 | #include <sys/param.h> |
48 | #include <sys/systm.h> |
49 | #include <sys/namei.h> |
50 | #include <sys/buf.h> |
51 | #include <sys/file.h> |
52 | #include <sys/stat.h> |
53 | #include <sys/mount.h> |
54 | #include <sys/vnode.h> |
55 | #include <sys/kernel.h> |
56 | #include <sys/kauth.h> |
57 | #include <sys/fstrans.h> |
58 | #include <sys/proc.h> |
59 | #include <sys/kmem.h> |
60 | |
61 | #include <ufs/lfs/lfs.h> |
62 | #include <ufs/lfs/lfs_accessors.h> |
63 | #include <ufs/lfs/lfs_extern.h> |
64 | |
65 | #include <ufs/lfs/ulfs_inode.h> |
66 | #ifdef LFS_DIRHASH |
67 | #include <ufs/lfs/ulfs_dirhash.h> |
68 | #endif |
69 | #include <ufs/lfs/ulfsmount.h> |
70 | #include <ufs/lfs/ulfs_extern.h> |
71 | #include <ufs/lfs/ulfs_bswap.h> |
72 | |
73 | #include <miscfs/genfs/genfs.h> |
74 | |
75 | #ifdef DIAGNOSTIC |
76 | int lfs_dirchk = 1; |
77 | #else |
78 | int lfs_dirchk = 0; |
79 | #endif |
80 | |
81 | /* |
82 | * Convert a component of a pathname into a pointer to a locked inode. |
83 | * This is a very central and rather complicated routine. |
84 | * If the file system is not maintained in a strict tree hierarchy, |
85 | * this can result in a deadlock situation (see comments in code below). |
86 | * |
87 | * The cnp->cn_nameiop argument is LOOKUP, CREATE, RENAME, or DELETE depending |
88 | * on whether the name is to be looked up, created, renamed, or deleted. |
89 | * When CREATE, RENAME, or DELETE is specified, information usable in |
90 | * creating, renaming, or deleting a directory entry may be calculated. |
91 | * If flag has LOCKPARENT or'ed into it and the target of the pathname |
92 | * exists, lookup returns both the target and its parent directory locked. |
93 | * When creating or renaming and LOCKPARENT is specified, the target may |
94 | * not be ".". When deleting and LOCKPARENT is specified, the target may |
95 | * be "."., but the caller must check to ensure it does an vrele and vput |
96 | * instead of two vputs. |
97 | * |
98 | * Overall outline of ulfs_lookup: |
99 | * |
100 | * check accessibility of directory |
101 | * look for name in cache, if found, then if at end of path |
102 | * and deleting or creating, drop it, else return name |
103 | * search for name in directory, to found or notfound |
104 | * notfound: |
105 | * if creating, return locked directory, leaving info on available slots |
106 | * else return error |
107 | * found: |
108 | * if at end of path and deleting, return information to allow delete |
109 | * if at end of path and rewriting (RENAME and LOCKPARENT), lock target |
110 | * inode and return info to allow rewrite |
111 | * if not at end, add name to cache; if at end and neither creating |
112 | * nor deleting, add name to cache |
113 | */ |
114 | int |
115 | ulfs_lookup(void *v) |
116 | { |
117 | struct vop_lookup_v2_args /* { |
118 | struct vnode *a_dvp; |
119 | struct vnode **a_vpp; |
120 | struct componentname *a_cnp; |
121 | } */ *ap = v; |
122 | struct vnode *vdp = ap->a_dvp; /* vnode for directory being searched */ |
123 | struct inode *dp = VTOI(vdp); /* inode for directory being searched */ |
124 | struct buf *bp; /* a buffer of directory entries */ |
125 | LFS_DIRHEADER *ep; /* the current directory entry */ |
126 | int entryoffsetinblock; /* offset of ep in bp's buffer */ |
127 | enum { |
128 | NONE, /* need to search a slot for our new entry */ |
129 | COMPACT, /* a compaction can make a slot in the current |
130 | DIRBLKSIZ block */ |
131 | FOUND, /* found a slot (or no need to search) */ |
132 | } slotstatus; |
133 | doff_t slotoffset; /* offset of area with free space. |
134 | a special value -1 for invalid */ |
135 | int slotsize; /* size of area at slotoffset */ |
136 | int slotfreespace; /* accumulated amount of space free in |
137 | the current DIRBLKSIZ block */ |
138 | int slotneeded; /* size of the entry we're seeking */ |
139 | int numdirpasses; /* strategy for directory search */ |
140 | doff_t endsearch; /* offset to end directory search */ |
141 | doff_t prevoff; /* previous value of ulr_offset */ |
142 | struct vnode *tdp; /* returned by vcache_get */ |
143 | doff_t enduseful; /* pointer past last used dir slot. |
144 | used for directory truncation. */ |
145 | u_long bmask; /* block offset mask */ |
146 | int error; |
147 | struct vnode **vpp = ap->a_vpp; |
148 | struct componentname *cnp = ap->a_cnp; |
149 | kauth_cred_t cred = cnp->cn_cred; |
150 | int flags; |
151 | int nameiop = cnp->cn_nameiop; |
152 | struct lfs *fs = dp->i_lfs; |
153 | int dirblksiz = fs->um_dirblksiz; |
154 | ino_t foundino; |
155 | struct ulfs_lookup_results *results; |
156 | int iswhiteout; /* temp result from cache_lookup() */ |
157 | |
158 | flags = cnp->cn_flags; |
159 | |
160 | bp = NULL; |
161 | slotoffset = -1; |
162 | *vpp = NULL; |
163 | endsearch = 0; /* silence compiler warning */ |
164 | |
165 | /* |
166 | * Produce the auxiliary lookup results into i_crap. Increment |
167 | * its serial number so elsewhere we can tell if we're using |
168 | * stale results. This should not be done this way. XXX. |
169 | */ |
170 | results = &dp->i_crap; |
171 | dp->i_crapcounter++; |
172 | |
173 | /* |
174 | * Check accessiblity of directory. |
175 | */ |
176 | if ((error = VOP_ACCESS(vdp, VEXEC, cred)) != 0) |
177 | return (error); |
178 | |
179 | if ((flags & ISLASTCN) && (vdp->v_mount->mnt_flag & MNT_RDONLY) && |
180 | (nameiop == DELETE || nameiop == RENAME)) |
181 | return (EROFS); |
182 | |
183 | /* |
184 | * We now have a segment name to search for, and a directory to search. |
185 | * |
186 | * Before tediously performing a linear scan of the directory, |
187 | * check the name cache to see if the directory/name pair |
188 | * we are looking for is known already. |
189 | */ |
190 | if (cache_lookup(vdp, cnp->cn_nameptr, cnp->cn_namelen, |
191 | cnp->cn_nameiop, cnp->cn_flags, &iswhiteout, vpp)) { |
192 | if (iswhiteout) { |
193 | cnp->cn_flags |= ISWHITEOUT; |
194 | } |
195 | return *vpp == NULLVP ? ENOENT : 0; |
196 | } |
197 | if (iswhiteout) { |
198 | /* |
199 | * The namecache set iswhiteout without finding a |
200 | * cache entry. As of this writing (20121014), this |
201 | * can happen if there was a whiteout entry that has |
202 | * been invalidated by the lookup. It is not clear if |
203 | * it is correct to set ISWHITEOUT in this case or |
204 | * not; however, doing so retains the prior behavior, |
205 | * so we'll go with that until some clearer answer |
206 | * appears. XXX |
207 | */ |
208 | cnp->cn_flags |= ISWHITEOUT; |
209 | } |
210 | |
211 | fstrans_start(vdp->v_mount, FSTRANS_SHARED); |
212 | |
213 | /* |
214 | * Suppress search for slots unless creating |
215 | * file and at end of pathname, in which case |
216 | * we watch for a place to put the new file in |
217 | * case it doesn't already exist. |
218 | */ |
219 | slotstatus = FOUND; |
220 | slotfreespace = slotsize = slotneeded = 0; |
221 | if ((nameiop == CREATE || nameiop == RENAME) && (flags & ISLASTCN)) { |
222 | slotstatus = NONE; |
223 | slotneeded = LFS_DIRECTSIZ(fs, cnp->cn_namelen); |
224 | } |
225 | |
226 | /* |
227 | * If there is cached information on a previous search of |
228 | * this directory, pick up where we last left off. |
229 | * We cache only lookups as these are the most common |
230 | * and have the greatest payoff. Caching CREATE has little |
231 | * benefit as it usually must search the entire directory |
232 | * to determine that the entry does not exist. Caching the |
233 | * location of the last DELETE or RENAME has not reduced |
234 | * profiling time and hence has been removed in the interest |
235 | * of simplicity. |
236 | */ |
237 | bmask = vdp->v_mount->mnt_stat.f_iosize - 1; |
238 | |
239 | #ifdef LFS_DIRHASH |
240 | /* |
241 | * Use dirhash for fast operations on large directories. The logic |
242 | * to determine whether to hash the directory is contained within |
243 | * ulfsdirhash_build(); a zero return means that it decided to hash |
244 | * this directory and it successfully built up the hash table. |
245 | */ |
246 | if (ulfsdirhash_build(dp) == 0) { |
247 | /* Look for a free slot if needed. */ |
248 | enduseful = dp->i_size; |
249 | if (slotstatus != FOUND) { |
250 | slotoffset = ulfsdirhash_findfree(dp, slotneeded, |
251 | &slotsize); |
252 | if (slotoffset >= 0) { |
253 | slotstatus = COMPACT; |
254 | enduseful = ulfsdirhash_enduseful(dp); |
255 | if (enduseful < 0) |
256 | enduseful = dp->i_size; |
257 | } |
258 | } |
259 | /* Look up the component. */ |
260 | numdirpasses = 1; |
261 | entryoffsetinblock = 0; /* silence compiler warning */ |
262 | switch (ulfsdirhash_lookup(dp, cnp->cn_nameptr, cnp->cn_namelen, |
263 | &results->ulr_offset, &bp, nameiop == DELETE ? &prevoff : NULL)) { |
264 | case 0: |
265 | ep = (LFS_DIRHEADER *)((char *)bp->b_data + |
266 | (results->ulr_offset & bmask)); |
267 | goto foundentry; |
268 | case ENOENT: |
269 | results->ulr_offset = roundup(dp->i_size, dirblksiz); |
270 | goto notfound; |
271 | default: |
272 | /* Something failed; just do a linear search. */ |
273 | break; |
274 | } |
275 | } |
276 | #endif /* LFS_DIRHASH */ |
277 | |
278 | if (nameiop != LOOKUP || results->ulr_diroff == 0 || |
279 | results->ulr_diroff >= dp->i_size) { |
280 | entryoffsetinblock = 0; |
281 | results->ulr_offset = 0; |
282 | numdirpasses = 1; |
283 | } else { |
284 | results->ulr_offset = results->ulr_diroff; |
285 | if ((entryoffsetinblock = results->ulr_offset & bmask) && |
286 | (error = ulfs_blkatoff(vdp, (off_t)results->ulr_offset, |
287 | NULL, &bp, false))) |
288 | goto out; |
289 | numdirpasses = 2; |
290 | namecache_count_2passes(); |
291 | } |
292 | prevoff = results->ulr_offset; |
293 | endsearch = roundup(dp->i_size, dirblksiz); |
294 | enduseful = 0; |
295 | |
296 | searchloop: |
297 | while (results->ulr_offset < endsearch) { |
298 | if (curcpu()->ci_schedstate.spc_flags & SPCF_SHOULDYIELD) |
299 | preempt(); |
300 | /* |
301 | * If necessary, get the next directory block. |
302 | */ |
303 | if ((results->ulr_offset & bmask) == 0) { |
304 | if (bp != NULL) |
305 | brelse(bp, 0); |
306 | error = ulfs_blkatoff(vdp, (off_t)results->ulr_offset, |
307 | NULL, &bp, false); |
308 | if (error) |
309 | goto out; |
310 | entryoffsetinblock = 0; |
311 | } |
312 | /* |
313 | * If still looking for a slot, and at a DIRBLKSIZ |
314 | * boundary, have to start looking for free space again. |
315 | */ |
316 | if (slotstatus == NONE && |
317 | (entryoffsetinblock & (dirblksiz - 1)) == 0) { |
318 | slotoffset = -1; |
319 | slotfreespace = 0; |
320 | } |
321 | /* |
322 | * Get pointer to next entry. |
323 | * Full validation checks are slow, so we only check |
324 | * enough to insure forward progress through the |
325 | * directory. Complete checks can be run by patching |
326 | * "lfs_dirchk" to be true. |
327 | */ |
328 | KASSERT(bp != NULL); |
329 | ep = (LFS_DIRHEADER *)((char *)bp->b_data + entryoffsetinblock); |
330 | if (lfs_dir_getreclen(fs, ep) == 0 || |
331 | (lfs_dirchk && ulfs_dirbadentry(vdp, ep, entryoffsetinblock))) { |
332 | int i; |
333 | |
334 | ulfs_dirbad(dp, results->ulr_offset, "mangled entry" ); |
335 | i = dirblksiz - (entryoffsetinblock & (dirblksiz - 1)); |
336 | results->ulr_offset += i; |
337 | entryoffsetinblock += i; |
338 | continue; |
339 | } |
340 | |
341 | /* |
342 | * If an appropriate sized slot has not yet been found, |
343 | * check to see if one is available. Also accumulate space |
344 | * in the current block so that we can determine if |
345 | * compaction is viable. |
346 | */ |
347 | if (slotstatus != FOUND) { |
348 | int size = lfs_dir_getreclen(fs, ep); |
349 | |
350 | if (lfs_dir_getino(fs, ep) != 0) |
351 | size -= LFS_DIRSIZ(fs, ep); |
352 | if (size > 0) { |
353 | if (size >= slotneeded) { |
354 | slotstatus = FOUND; |
355 | slotoffset = results->ulr_offset; |
356 | slotsize = lfs_dir_getreclen(fs, ep); |
357 | } else if (slotstatus == NONE) { |
358 | slotfreespace += size; |
359 | if (slotoffset == -1) |
360 | slotoffset = results->ulr_offset; |
361 | if (slotfreespace >= slotneeded) { |
362 | slotstatus = COMPACT; |
363 | slotsize = results->ulr_offset + |
364 | lfs_dir_getreclen(fs, ep) - |
365 | slotoffset; |
366 | } |
367 | } |
368 | } |
369 | } |
370 | |
371 | /* |
372 | * Check for a name match. |
373 | */ |
374 | if (lfs_dir_getino(fs, ep)) { |
375 | int namlen; |
376 | |
377 | namlen = lfs_dir_getnamlen(fs, ep); |
378 | if (namlen == cnp->cn_namelen && |
379 | !memcmp(cnp->cn_nameptr, lfs_dir_nameptr(fs, ep), |
380 | (unsigned)namlen)) { |
381 | #ifdef LFS_DIRHASH |
382 | foundentry: |
383 | #endif |
384 | /* |
385 | * Save directory entry's inode number and |
386 | * reclen, and release directory buffer. |
387 | */ |
388 | if (!FSFMT(vdp) && lfs_dir_gettype(fs, ep) == LFS_DT_WHT) { |
389 | slotstatus = FOUND; |
390 | slotoffset = results->ulr_offset; |
391 | slotsize = lfs_dir_getreclen(fs, ep); |
392 | results->ulr_reclen = slotsize; |
393 | /* |
394 | * This is used to set |
395 | * results->ulr_endoff, |
396 | * which may be used by ulfs_direnter() |
397 | * as a length to truncate the |
398 | * directory to. Therefore, it must |
399 | * point past the end of the last |
400 | * non-empty directory entry. We don't |
401 | * know where that is in this case, so |
402 | * we effectively disable shrinking by |
403 | * using the existing size of the |
404 | * directory. |
405 | * |
406 | * Note that we wouldn't expect to |
407 | * shrink the directory while rewriting |
408 | * an existing entry anyway. |
409 | */ |
410 | enduseful = endsearch; |
411 | cnp->cn_flags |= ISWHITEOUT; |
412 | numdirpasses--; |
413 | goto notfound; |
414 | } |
415 | foundino = lfs_dir_getino(fs, ep); |
416 | results->ulr_reclen = lfs_dir_getreclen(fs, ep); |
417 | goto found; |
418 | } |
419 | } |
420 | prevoff = results->ulr_offset; |
421 | results->ulr_offset += lfs_dir_getreclen(fs, ep); |
422 | entryoffsetinblock += lfs_dir_getreclen(fs, ep); |
423 | if (lfs_dir_getino(fs, ep)) |
424 | enduseful = results->ulr_offset; |
425 | } |
426 | notfound: |
427 | /* |
428 | * If we started in the middle of the directory and failed |
429 | * to find our target, we must check the beginning as well. |
430 | */ |
431 | if (numdirpasses == 2) { |
432 | numdirpasses--; |
433 | results->ulr_offset = 0; |
434 | endsearch = results->ulr_diroff; |
435 | goto searchloop; |
436 | } |
437 | if (bp != NULL) |
438 | brelse(bp, 0); |
439 | /* |
440 | * If creating, and at end of pathname and current |
441 | * directory has not been removed, then can consider |
442 | * allowing file to be created. |
443 | */ |
444 | if ((nameiop == CREATE || nameiop == RENAME || |
445 | (nameiop == DELETE && |
446 | (cnp->cn_flags & DOWHITEOUT) && |
447 | (cnp->cn_flags & ISWHITEOUT))) && |
448 | (flags & ISLASTCN) && dp->i_nlink != 0) { |
449 | /* |
450 | * Access for write is interpreted as allowing |
451 | * creation of files in the directory. |
452 | */ |
453 | error = VOP_ACCESS(vdp, VWRITE, cred); |
454 | if (error) |
455 | goto out; |
456 | /* |
457 | * Return an indication of where the new directory |
458 | * entry should be put. If we didn't find a slot, |
459 | * then set results->ulr_count to 0 indicating |
460 | * that the new slot belongs at the end of the |
461 | * directory. If we found a slot, then the new entry |
462 | * can be put in the range from results->ulr_offset to |
463 | * results->ulr_offset + results->ulr_count. |
464 | */ |
465 | if (slotstatus == NONE) { |
466 | results->ulr_offset = roundup(dp->i_size, dirblksiz); |
467 | results->ulr_count = 0; |
468 | enduseful = results->ulr_offset; |
469 | } else if (nameiop == DELETE) { |
470 | results->ulr_offset = slotoffset; |
471 | if ((results->ulr_offset & (dirblksiz - 1)) == 0) |
472 | results->ulr_count = 0; |
473 | else |
474 | results->ulr_count = |
475 | results->ulr_offset - prevoff; |
476 | } else { |
477 | results->ulr_offset = slotoffset; |
478 | results->ulr_count = slotsize; |
479 | if (enduseful < slotoffset + slotsize) |
480 | enduseful = slotoffset + slotsize; |
481 | } |
482 | results->ulr_endoff = roundup(enduseful, dirblksiz); |
483 | #if 0 /* commented out by dbj. none of the on disk fields changed */ |
484 | dp->i_flag |= IN_CHANGE | IN_UPDATE; |
485 | #endif |
486 | /* |
487 | * We return with the directory locked, so that |
488 | * the parameters we set up above will still be |
489 | * valid if we actually decide to do a direnter(). |
490 | * We return ni_vp == NULL to indicate that the entry |
491 | * does not currently exist; we leave a pointer to |
492 | * the (locked) directory inode in ndp->ni_dvp. |
493 | * |
494 | * NB - if the directory is unlocked, then this |
495 | * information cannot be used. |
496 | */ |
497 | error = EJUSTRETURN; |
498 | goto out; |
499 | } |
500 | /* |
501 | * Insert name into cache (as non-existent) if appropriate. |
502 | */ |
503 | if (nameiop != CREATE) { |
504 | cache_enter(vdp, *vpp, cnp->cn_nameptr, cnp->cn_namelen, |
505 | cnp->cn_flags); |
506 | } |
507 | error = ENOENT; |
508 | goto out; |
509 | |
510 | found: |
511 | if (numdirpasses == 2) |
512 | namecache_count_pass2(); |
513 | /* |
514 | * Check that directory length properly reflects presence |
515 | * of this entry. |
516 | */ |
517 | if (results->ulr_offset + LFS_DIRSIZ(fs, ep) > dp->i_size) { |
518 | ulfs_dirbad(dp, results->ulr_offset, "i_size too small" ); |
519 | dp->i_size = |
520 | results->ulr_offset + LFS_DIRSIZ(fs, ep); |
521 | DIP_ASSIGN(dp, size, dp->i_size); |
522 | dp->i_flag |= IN_CHANGE | IN_UPDATE; |
523 | } |
524 | brelse(bp, 0); |
525 | |
526 | /* |
527 | * Found component in pathname. |
528 | * If the final component of path name, save information |
529 | * in the cache as to where the entry was found. |
530 | */ |
531 | if ((flags & ISLASTCN) && nameiop == LOOKUP) |
532 | results->ulr_diroff = results->ulr_offset &~ (dirblksiz - 1); |
533 | |
534 | /* |
535 | * If deleting, and at end of pathname, return |
536 | * parameters which can be used to remove file. |
537 | * Lock the inode, being careful with ".". |
538 | */ |
539 | if (nameiop == DELETE && (flags & ISLASTCN)) { |
540 | /* |
541 | * Return pointer to current entry in results->ulr_offset, |
542 | * and distance past previous entry (if there |
543 | * is a previous entry in this block) in results->ulr_count. |
544 | * Save directory inode pointer in ndp->ni_dvp for dirremove(). |
545 | */ |
546 | if ((results->ulr_offset & (dirblksiz - 1)) == 0) |
547 | results->ulr_count = 0; |
548 | else |
549 | results->ulr_count = results->ulr_offset - prevoff; |
550 | if (dp->i_number == foundino) { |
551 | vref(vdp); |
552 | tdp = vdp; |
553 | } else { |
554 | error = vcache_get(vdp->v_mount, |
555 | &foundino, sizeof(foundino), &tdp); |
556 | if (error) |
557 | goto out; |
558 | } |
559 | /* |
560 | * Write access to directory required to delete files. |
561 | */ |
562 | error = VOP_ACCESS(vdp, VWRITE, cred); |
563 | if (error) { |
564 | vrele(tdp); |
565 | goto out; |
566 | } |
567 | /* |
568 | * If directory is "sticky", then user must own |
569 | * the directory, or the file in it, else she |
570 | * may not delete it (unless she's root). This |
571 | * implements append-only directories. |
572 | */ |
573 | if (dp->i_mode & ISVTX) { |
574 | error = kauth_authorize_vnode(cred, KAUTH_VNODE_DELETE, |
575 | tdp, vdp, genfs_can_sticky(cred, dp->i_uid, |
576 | VTOI(tdp)->i_uid)); |
577 | if (error) { |
578 | vrele(tdp); |
579 | error = EPERM; |
580 | goto out; |
581 | } |
582 | } |
583 | *vpp = tdp; |
584 | error = 0; |
585 | goto out; |
586 | } |
587 | |
588 | /* |
589 | * If rewriting (RENAME), return the inode and the |
590 | * information required to rewrite the present directory |
591 | * Must get inode of directory entry to verify it's a |
592 | * regular file, or empty directory. |
593 | */ |
594 | if (nameiop == RENAME && (flags & ISLASTCN)) { |
595 | error = VOP_ACCESS(vdp, VWRITE, cred); |
596 | if (error) |
597 | goto out; |
598 | /* |
599 | * Careful about locking second inode. |
600 | * This can only occur if the target is ".". |
601 | */ |
602 | if (dp->i_number == foundino) { |
603 | error = EISDIR; |
604 | goto out; |
605 | } |
606 | error = vcache_get(vdp->v_mount, |
607 | &foundino, sizeof(foundino), &tdp); |
608 | if (error) |
609 | goto out; |
610 | *vpp = tdp; |
611 | error = 0; |
612 | goto out; |
613 | } |
614 | |
615 | if (dp->i_number == foundino) { |
616 | vref(vdp); /* we want ourself, ie "." */ |
617 | *vpp = vdp; |
618 | } else { |
619 | error = vcache_get(vdp->v_mount, |
620 | &foundino, sizeof(foundino), &tdp); |
621 | if (error) |
622 | goto out; |
623 | *vpp = tdp; |
624 | } |
625 | |
626 | /* |
627 | * Insert name into cache if appropriate. |
628 | */ |
629 | cache_enter(vdp, *vpp, cnp->cn_nameptr, cnp->cn_namelen, cnp->cn_flags); |
630 | error = 0; |
631 | |
632 | out: |
633 | fstrans_done(vdp->v_mount); |
634 | return error; |
635 | } |
636 | |
637 | void |
638 | ulfs_dirbad(struct inode *ip, doff_t offset, const char *how) |
639 | { |
640 | struct mount *mp; |
641 | |
642 | mp = ITOV(ip)->v_mount; |
643 | printf("%s: bad dir ino %llu at offset %d: %s\n" , |
644 | mp->mnt_stat.f_mntonname, (unsigned long long)ip->i_number, |
645 | offset, how); |
646 | if ((mp->mnt_flag & MNT_RDONLY) == 0) |
647 | panic("bad dir" ); |
648 | } |
649 | |
650 | /* |
651 | * Do consistency checking on a directory entry: |
652 | * record length must be multiple of 4 |
653 | * entry must fit in rest of its DIRBLKSIZ block |
654 | * record must be large enough to contain entry |
655 | * name is not longer than LFS_MAXNAMLEN |
656 | * name must be as long as advertised, and null terminated |
657 | */ |
658 | int |
659 | ulfs_dirbadentry(struct vnode *dp, LFS_DIRHEADER *ep, int entryoffsetinblock) |
660 | { |
661 | int i; |
662 | int namlen; |
663 | unsigned reclen; |
664 | struct ulfsmount *ump = VFSTOULFS(dp->v_mount); |
665 | struct lfs *fs = ump->um_lfs; |
666 | int dirblksiz = fs->um_dirblksiz; |
667 | const char *name; |
668 | |
669 | namlen = lfs_dir_getnamlen(fs, ep); |
670 | reclen = lfs_dir_getreclen(fs, ep); |
671 | if ((reclen & 0x3) != 0 || |
672 | reclen > dirblksiz - (entryoffsetinblock & (dirblksiz - 1)) || |
673 | reclen < LFS_DIRSIZ(fs, ep) || namlen > LFS_MAXNAMLEN) { |
674 | /*return (1); */ |
675 | printf("First bad, reclen=%#x, DIRSIZ=%lu, namlen=%d, " |
676 | "flags=%#x, entryoffsetinblock=%d, dirblksiz = %d\n" , |
677 | lfs_dir_getreclen(fs, ep), |
678 | (u_long)LFS_DIRSIZ(fs, ep), |
679 | namlen, dp->v_mount->mnt_flag, entryoffsetinblock, |
680 | dirblksiz); |
681 | goto bad; |
682 | } |
683 | if (lfs_dir_getino(fs, ep) == 0) |
684 | return (0); |
685 | name = lfs_dir_nameptr(fs, ep); |
686 | for (i = 0; i < namlen; i++) |
687 | if (name[i] == '\0') { |
688 | /*return (1); */ |
689 | printf("Second bad\n" ); |
690 | goto bad; |
691 | } |
692 | if (name[i]) |
693 | goto bad; |
694 | return (0); |
695 | bad: |
696 | return (1); |
697 | } |
698 | |
699 | /* |
700 | * Assign the contents of directory entry DIRP, on volume FS. |
701 | * |
702 | * NAME/NAMLEN is the name, which is not necessarily null terminated. |
703 | * INUM is the inode number, and DTYPE is the type code (LFS_DT_*). |
704 | * |
705 | * Note that these values typically come from: |
706 | * cnp->cn_nameptr |
707 | * cnp->cn_namelen |
708 | * ip->i_number |
709 | * LFS_IFTODT(ip->i_mode) |
710 | * |
711 | * Does not set d_reclen. |
712 | */ |
713 | static void |
714 | ulfs_direntry_assign(struct lfs *fs, LFS_DIRHEADER *dirp, |
715 | const char *name, size_t namlen, |
716 | ino_t inum, unsigned dtype) |
717 | { |
718 | lfs_dir_setino(fs, dirp, inum); |
719 | lfs_dir_setnamlen(fs, dirp, namlen); |
720 | lfs_dir_settype(fs, dirp, dtype); |
721 | memcpy(lfs_dir_nameptr(fs, dirp), name, namlen); |
722 | lfs_dir_nameptr(fs, dirp)[namlen] = '\0'; |
723 | } |
724 | |
725 | /* |
726 | * Write a directory entry after a call to namei, using the parameters |
727 | * that ulfs_lookup left in nameidata and in the ulfs_lookup_results. |
728 | * |
729 | * DVP is the directory to be updated. It must be locked. |
730 | * ULR is the ulfs_lookup_results structure from the final lookup step. |
731 | * TVP is not used. (XXX: why is it here? remove it) |
732 | * CNP is the componentname from the final lookup step. |
733 | * INUM is the inode number to insert into the new directory entry. |
734 | * DTYPE is the type code (LFS_DT_*) to insert into the new directory entry. |
735 | * NEWDIRBP is not used and (XXX) should be removed. The previous |
736 | * comment here said it was used by the now-removed softupdates code. |
737 | * |
738 | * The link count of the target inode is *not* incremented; the |
739 | * caller does that. |
740 | * |
741 | * If ulr->ulr_count is 0, ulfs_lookup did not find space to insert the |
742 | * directory entry. ulr_offset, which is the place to put the entry, |
743 | * should be on a block boundary (and should be at the end of the |
744 | * directory AFAIK) and a fresh block is allocated to put the new |
745 | * directory entry in. |
746 | * |
747 | * If ulr->ulr_count is not zero, ulfs_lookup found a slot to insert |
748 | * the entry into. This slot ranges from ulr_offset to ulr_offset + |
749 | * ulr_count. However, this slot may already be partially populated |
750 | * requiring compaction. See notes below. |
751 | * |
752 | * Furthermore, if ulr_count is not zero and ulr_endoff is not the |
753 | * same as i_size, the directory is truncated to size ulr_endoff. |
754 | */ |
755 | int |
756 | ulfs_direnter(struct vnode *dvp, const struct ulfs_lookup_results *ulr, |
757 | struct vnode *tvp, |
758 | struct componentname *cnp, ino_t inum, unsigned dtype, |
759 | struct buf *newdirbp) |
760 | { |
761 | kauth_cred_t cr; |
762 | int newentrysize; |
763 | struct inode *dp; |
764 | struct buf *bp; |
765 | u_int dsize; |
766 | LFS_DIRHEADER *ep, *nep; |
767 | int error, ret, lfs_blkoff, loc, spacefree; |
768 | char *dirbuf; |
769 | struct timespec ts; |
770 | struct ulfsmount *ump = VFSTOULFS(dvp->v_mount); |
771 | struct lfs *fs = ump->um_lfs; |
772 | int dirblksiz = fs->um_dirblksiz; |
773 | const char *name; |
774 | unsigned namlen, reclen; |
775 | #ifdef LFS_DIRHASH |
776 | int dohashadd; |
777 | #endif |
778 | |
779 | error = 0; |
780 | name = cnp->cn_nameptr; /* note: not null-terminated */ |
781 | namlen = cnp->cn_namelen; |
782 | cr = cnp->cn_cred; |
783 | |
784 | dp = VTOI(dvp); |
785 | newentrysize = LFS_DIRECTSIZ(fs, namlen); |
786 | |
787 | if (ulr->ulr_count == 0) { |
788 | /* |
789 | * If ulr_count is 0, then namei could find no |
790 | * space in the directory. Here, ulr_offset will |
791 | * be on a directory block boundary and we will write the |
792 | * new entry into a fresh block. |
793 | */ |
794 | if (ulr->ulr_offset & (dirblksiz - 1)) |
795 | panic("ulfs_direnter: newblk" ); |
796 | if ((error = lfs_balloc(dvp, (off_t)ulr->ulr_offset, dirblksiz, |
797 | cr, B_CLRBUF | B_SYNC, &bp)) != 0) { |
798 | return (error); |
799 | } |
800 | dp->i_size = ulr->ulr_offset + dirblksiz; |
801 | DIP_ASSIGN(dp, size, dp->i_size); |
802 | dp->i_flag |= IN_CHANGE | IN_UPDATE; |
803 | uvm_vnp_setsize(dvp, dp->i_size); |
804 | lfs_blkoff = ulr->ulr_offset & (ump->um_mountp->mnt_stat.f_iosize - 1); |
805 | ep = (LFS_DIRHEADER *)((char *)bp->b_data + lfs_blkoff); |
806 | ulfs_direntry_assign(fs, ep, name, namlen, inum, dtype); |
807 | lfs_dir_setreclen(fs, ep, dirblksiz); |
808 | #ifdef LFS_DIRHASH |
809 | if (dp->i_dirhash != NULL) { |
810 | ulfsdirhash_newblk(dp, ulr->ulr_offset); |
811 | ulfsdirhash_add(dp, ep, ulr->ulr_offset); |
812 | ulfsdirhash_checkblock(dp, (char *)bp->b_data + lfs_blkoff, |
813 | ulr->ulr_offset); |
814 | } |
815 | #endif |
816 | error = VOP_BWRITE(bp->b_vp, bp); |
817 | vfs_timestamp(&ts); |
818 | ret = lfs_update(dvp, &ts, &ts, UPDATE_DIROP); |
819 | if (error == 0) |
820 | return (ret); |
821 | return (error); |
822 | } |
823 | |
824 | /* |
825 | * If ulr_count is non-zero, then namei found space for the new |
826 | * entry in the range ulr_offset to ulr_offset + ulr_count |
827 | * in the directory. To use this space, we may have to compact |
828 | * the entries located there, by copying them together towards the |
829 | * beginning of the block, leaving the free space in one usable |
830 | * chunk at the end. |
831 | */ |
832 | |
833 | /* |
834 | * Increase size of directory if entry eats into new space. |
835 | * This should never push the size past a new multiple of |
836 | * DIRBLKSIZ. |
837 | * |
838 | * N.B. - THIS IS AN ARTIFACT OF 4.2 AND SHOULD NEVER HAPPEN. |
839 | */ |
840 | if (ulr->ulr_offset + ulr->ulr_count > dp->i_size) { |
841 | #ifdef DIAGNOSTIC |
842 | printf("ulfs_direnter: reached 4.2-only block, " |
843 | "not supposed to happen\n" ); |
844 | #endif |
845 | dp->i_size = ulr->ulr_offset + ulr->ulr_count; |
846 | DIP_ASSIGN(dp, size, dp->i_size); |
847 | dp->i_flag |= IN_CHANGE | IN_UPDATE; |
848 | } |
849 | /* |
850 | * Get the block containing the space for the new directory entry. |
851 | */ |
852 | error = ulfs_blkatoff(dvp, (off_t)ulr->ulr_offset, &dirbuf, &bp, true); |
853 | if (error) { |
854 | return (error); |
855 | } |
856 | /* |
857 | * Find space for the new entry. In the simple case, the entry at |
858 | * offset base will have the space. If it does not, then namei |
859 | * arranged that compacting the region ulr_offset to |
860 | * ulr_offset + ulr_count would yield the space. |
861 | */ |
862 | ep = (LFS_DIRHEADER *)dirbuf; |
863 | dsize = (lfs_dir_getino(fs, ep) != 0) ? LFS_DIRSIZ(fs, ep) : 0; |
864 | spacefree = lfs_dir_getreclen(fs, ep) - dsize; |
865 | for (loc = lfs_dir_getreclen(fs, ep); loc < ulr->ulr_count; ) { |
866 | nep = (LFS_DIRHEADER *)(dirbuf + loc); |
867 | |
868 | /* Trim the existing slot (NB: dsize may be zero). */ |
869 | lfs_dir_setreclen(fs, ep, dsize); |
870 | ep = LFS_NEXTDIR(fs, ep); |
871 | |
872 | reclen = lfs_dir_getreclen(fs, nep); |
873 | loc += reclen; |
874 | if (lfs_dir_getino(fs, nep) == 0) { |
875 | /* |
876 | * A mid-block unused entry. Such entries are |
877 | * never created by the kernel, but fsck_ffs |
878 | * can create them (and it doesn't fix them). |
879 | * |
880 | * Add up the free space, and initialise the |
881 | * relocated entry since we don't memcpy it. |
882 | */ |
883 | spacefree += reclen; |
884 | lfs_dir_setino(fs, ep, 0); |
885 | dsize = 0; |
886 | continue; |
887 | } |
888 | dsize = LFS_DIRSIZ(fs, nep); |
889 | spacefree += reclen - dsize; |
890 | #ifdef LFS_DIRHASH |
891 | if (dp->i_dirhash != NULL) |
892 | ulfsdirhash_move(dp, nep, |
893 | ulr->ulr_offset + ((char *)nep - dirbuf), |
894 | ulr->ulr_offset + ((char *)ep - dirbuf)); |
895 | #endif |
896 | memcpy((void *)ep, (void *)nep, dsize); |
897 | } |
898 | /* |
899 | * Here, `ep' points to a directory entry containing `dsize' in-use |
900 | * bytes followed by `spacefree' unused bytes. If ep->d_ino == 0, |
901 | * then the entry is completely unused (dsize == 0). The value |
902 | * of ep->d_reclen is always indeterminate. |
903 | * |
904 | * Update the pointer fields in the previous entry (if any), |
905 | * copy in the new entry, and write out the block. |
906 | */ |
907 | if (lfs_dir_getino(fs, ep) == 0 || |
908 | (lfs_dir_getino(fs, ep) == ULFS_WINO && |
909 | memcmp(lfs_dir_nameptr(fs, ep), name, namlen) == 0)) { |
910 | if (spacefree + dsize < newentrysize) |
911 | panic("ulfs_direnter: compact1" ); |
912 | reclen = spacefree + dsize; |
913 | #ifdef LFS_DIRHASH |
914 | dohashadd = (lfs_dir_getino(fs, ep) == 0); |
915 | #endif |
916 | } else { |
917 | if (spacefree < newentrysize) |
918 | panic("ulfs_direnter: compact2" ); |
919 | reclen = spacefree; |
920 | lfs_dir_setreclen(fs, ep, dsize); |
921 | ep = LFS_NEXTDIR(fs, ep); |
922 | #ifdef LFS_DIRHASH |
923 | dohashadd = 1; |
924 | #endif |
925 | } |
926 | |
927 | ulfs_direntry_assign(fs, ep, name, namlen, inum, dtype); |
928 | lfs_dir_setreclen(fs, ep, reclen); |
929 | #ifdef LFS_DIRHASH |
930 | if (dp->i_dirhash != NULL && dohashadd) |
931 | ulfsdirhash_add(dp, ep, ulr->ulr_offset + ((char *)ep - dirbuf)); |
932 | if (dp->i_dirhash != NULL) |
933 | ulfsdirhash_checkblock(dp, dirbuf - |
934 | (ulr->ulr_offset & (dirblksiz - 1)), |
935 | ulr->ulr_offset & ~(dirblksiz - 1)); |
936 | #endif |
937 | error = VOP_BWRITE(bp->b_vp, bp); |
938 | dp->i_flag |= IN_CHANGE | IN_UPDATE; |
939 | /* |
940 | * If all went well, and the directory can be shortened, proceed |
941 | * with the truncation. Note that we have to unlock the inode for |
942 | * the entry that we just entered, as the truncation may need to |
943 | * lock other inodes which can lead to deadlock if we also hold a |
944 | * lock on the newly entered node. |
945 | */ |
946 | if (error == 0 && ulr->ulr_endoff && ulr->ulr_endoff < dp->i_size) { |
947 | #ifdef LFS_DIRHASH |
948 | if (dp->i_dirhash != NULL) |
949 | ulfsdirhash_dirtrunc(dp, ulr->ulr_endoff); |
950 | #endif |
951 | (void) lfs_truncate(dvp, (off_t)ulr->ulr_endoff, IO_SYNC, cr); |
952 | } |
953 | return (error); |
954 | } |
955 | |
956 | /* |
957 | * Remove a directory entry after a call to namei, using the |
958 | * parameters that ulfs_lookup left in nameidata and in the |
959 | * ulfs_lookup_results. |
960 | * |
961 | * DVP is the directory to be updated. It must be locked. |
962 | * ULR is the ulfs_lookup_results structure from the final lookup step. |
963 | * IP, if not null, is the inode being unlinked. |
964 | * FLAGS may contain DOWHITEOUT. |
965 | * ISRMDIR is not used and (XXX) should be removed. |
966 | * |
967 | * If FLAGS contains DOWHITEOUT the entry is replaced with a whiteout |
968 | * instead of being cleared. |
969 | * |
970 | * ulr->ulr_offset contains the position of the directory entry |
971 | * to be removed. |
972 | * |
973 | * ulr->ulr_reclen contains the size of the directory entry to be |
974 | * removed. |
975 | * |
976 | * ulr->ulr_count contains the size of the *previous* directory |
977 | * entry. This allows finding it, for free space management. If |
978 | * ulr_count is 0, the target entry is at the beginning of the |
979 | * directory. (Does this ever happen? The first entry should be ".", |
980 | * which should only be removed at rmdir time. Does rmdir come here |
981 | * to clear out the "." and ".." entries? Perhaps, but I doubt it.) |
982 | * |
983 | * The space is marked free by adding it to the record length (not |
984 | * name length) of the preceding entry. If the first entry becomes |
985 | * free, it is marked free by setting the inode number to 0. |
986 | * |
987 | * The link count of IP is decremented. Note that this is not the |
988 | * inverse behavior of ulfs_direnter, which does not adjust link |
989 | * counts. Sigh. |
990 | */ |
991 | int |
992 | ulfs_dirremove(struct vnode *dvp, const struct ulfs_lookup_results *ulr, |
993 | struct inode *ip, int flags, int isrmdir) |
994 | { |
995 | struct inode *dp = VTOI(dvp); |
996 | struct lfs *fs = dp->i_lfs; |
997 | LFS_DIRHEADER *ep; |
998 | struct buf *bp; |
999 | int error; |
1000 | |
1001 | if (flags & DOWHITEOUT) { |
1002 | /* |
1003 | * Whiteout entry: set d_ino to ULFS_WINO. |
1004 | */ |
1005 | error = ulfs_blkatoff(dvp, (off_t)ulr->ulr_offset, (void *)&ep, |
1006 | &bp, true); |
1007 | if (error) |
1008 | return (error); |
1009 | lfs_dir_setino(fs, ep, ULFS_WINO); |
1010 | lfs_dir_settype(fs, ep, LFS_DT_WHT); |
1011 | goto out; |
1012 | } |
1013 | |
1014 | if ((error = ulfs_blkatoff(dvp, |
1015 | (off_t)(ulr->ulr_offset - ulr->ulr_count), (void *)&ep, &bp, true)) != 0) |
1016 | return (error); |
1017 | |
1018 | #ifdef LFS_DIRHASH |
1019 | /* |
1020 | * Remove the dirhash entry. This is complicated by the fact |
1021 | * that `ep' is the previous entry when ulr_count != 0. |
1022 | */ |
1023 | if (dp->i_dirhash != NULL) |
1024 | ulfsdirhash_remove(dp, (ulr->ulr_count == 0) ? ep : |
1025 | LFS_NEXTDIR(fs, ep), ulr->ulr_offset); |
1026 | #endif |
1027 | |
1028 | if (ulr->ulr_count == 0) { |
1029 | /* |
1030 | * First entry in block: set d_ino to zero. |
1031 | */ |
1032 | lfs_dir_setino(fs, ep, 0); |
1033 | } else { |
1034 | /* |
1035 | * Collapse new free space into previous entry. |
1036 | */ |
1037 | lfs_dir_setreclen(fs, ep, |
1038 | lfs_dir_getreclen(fs, ep) + ulr->ulr_reclen); |
1039 | } |
1040 | |
1041 | #ifdef LFS_DIRHASH |
1042 | if (dp->i_dirhash != NULL) { |
1043 | int dirblksiz = ip->i_lfs->um_dirblksiz; |
1044 | ulfsdirhash_checkblock(dp, (char *)ep - |
1045 | ((ulr->ulr_offset - ulr->ulr_count) & (dirblksiz - 1)), |
1046 | ulr->ulr_offset & ~(dirblksiz - 1)); |
1047 | } |
1048 | #endif |
1049 | |
1050 | out: |
1051 | if (ip) { |
1052 | ip->i_nlink--; |
1053 | DIP_ASSIGN(ip, nlink, ip->i_nlink); |
1054 | ip->i_flag |= IN_CHANGE; |
1055 | } |
1056 | /* |
1057 | * XXX did it ever occur to anyone that it might be a good |
1058 | * idea to restore ip->i_nlink if this fails? Or something? |
1059 | * Currently on error return from this function the state of |
1060 | * ip->i_nlink depends on what happened, and callers |
1061 | * definitely do not take this into account. |
1062 | */ |
1063 | error = VOP_BWRITE(bp->b_vp, bp); |
1064 | dp->i_flag |= IN_CHANGE | IN_UPDATE; |
1065 | /* |
1066 | * If the last named reference to a snapshot goes away, |
1067 | * drop its snapshot reference so that it will be reclaimed |
1068 | * when last open reference goes away. |
1069 | */ |
1070 | if (ip != 0 && (ip->i_flags & SF_SNAPSHOT) != 0 && |
1071 | ip->i_nlink == 0) |
1072 | ulfs_snapgone(ip); |
1073 | return (error); |
1074 | } |
1075 | |
1076 | /* |
1077 | * Rewrite an existing directory entry to point at the inode supplied. |
1078 | * |
1079 | * DP is the directory to update. |
1080 | * OFFSET is the position of the entry in question. It may come |
1081 | * from ulr_offset of a ulfs_lookup_results. |
1082 | * OIP is the old inode the directory previously pointed to. |
1083 | * NEWINUM is the number of the new inode. |
1084 | * NEWTYPE is the new value for the type field of the directory entry. |
1085 | * (This is ignored if the fs doesn't support that.) |
1086 | * ISRMDIR is not used and (XXX) should be removed. |
1087 | * IFLAGS are added to DP's inode flags. |
1088 | * |
1089 | * The link count of OIP is decremented. Note that the link count of |
1090 | * the new inode is *not* incremented. Yay for symmetry. |
1091 | */ |
1092 | int |
1093 | ulfs_dirrewrite(struct inode *dp, off_t offset, |
1094 | struct inode *oip, ino_t newinum, int newtype, |
1095 | int isrmdir, int iflags) |
1096 | { |
1097 | struct lfs *fs = dp->i_lfs; |
1098 | struct buf *bp; |
1099 | LFS_DIRHEADER *ep; |
1100 | struct vnode *vdp = ITOV(dp); |
1101 | int error; |
1102 | |
1103 | error = ulfs_blkatoff(vdp, offset, (void *)&ep, &bp, true); |
1104 | if (error) |
1105 | return (error); |
1106 | lfs_dir_setino(fs, ep, newinum); |
1107 | lfs_dir_settype(fs, ep, newtype); |
1108 | oip->i_nlink--; |
1109 | DIP_ASSIGN(oip, nlink, oip->i_nlink); |
1110 | oip->i_flag |= IN_CHANGE; |
1111 | error = VOP_BWRITE(bp->b_vp, bp); |
1112 | dp->i_flag |= iflags; |
1113 | /* |
1114 | * If the last named reference to a snapshot goes away, |
1115 | * drop its snapshot reference so that it will be reclaimed |
1116 | * when last open reference goes away. |
1117 | */ |
1118 | if ((oip->i_flags & SF_SNAPSHOT) != 0 && oip->i_nlink == 0) |
1119 | ulfs_snapgone(oip); |
1120 | return (error); |
1121 | } |
1122 | |
1123 | /* |
1124 | * Check if a directory is empty or not. |
1125 | * Inode supplied must be locked. |
1126 | * |
1127 | * Using a struct lfs_dirtemplate here is not precisely |
1128 | * what we want, but better than using a struct lfs_direct. |
1129 | * |
1130 | * NB: does not handle corrupted directories. |
1131 | */ |
1132 | int |
1133 | ulfs_dirempty(struct inode *ip, ino_t parentino, kauth_cred_t cred) |
1134 | { |
1135 | struct lfs *fs = ip->i_lfs; |
1136 | doff_t off; |
1137 | union lfs_dirtemplate dbuf; |
1138 | LFS_DIRHEADER *dp = (LFS_DIRHEADER *)&dbuf; |
1139 | int error, namlen; |
1140 | const char *name; |
1141 | size_t count; |
1142 | /* XXX this should probably use LFS_DIRECTSIZ(fs, 2) */ |
1143 | #define MINDIRSIZ (sizeof (struct lfs_dirtemplate64) / 2) |
1144 | |
1145 | for (off = 0; off < ip->i_size; off += lfs_dir_getreclen(fs, dp)) { |
1146 | error = ulfs_bufio(UIO_READ, ITOV(ip), (void *)dp, MINDIRSIZ, |
1147 | off, IO_NODELOCKED, cred, &count, NULL); |
1148 | /* |
1149 | * Since we read MINDIRSIZ, residual must |
1150 | * be 0 unless we're at end of file. |
1151 | */ |
1152 | if (error || count != 0) |
1153 | return (0); |
1154 | /* avoid infinite loops */ |
1155 | if (lfs_dir_getreclen(fs, dp) == 0) |
1156 | return (0); |
1157 | /* skip empty entries */ |
1158 | if (lfs_dir_getino(fs, dp) == 0 || |
1159 | lfs_dir_getino(fs, dp) == ULFS_WINO) |
1160 | continue; |
1161 | /* accept only "." and ".." */ |
1162 | namlen = lfs_dir_getnamlen(fs, dp); |
1163 | name = lfs_dir_nameptr(fs, dp); |
1164 | if (namlen > 2) |
1165 | return (0); |
1166 | if (name[0] != '.') |
1167 | return (0); |
1168 | /* |
1169 | * At this point namlen must be 1 or 2. |
1170 | * 1 implies ".", 2 implies ".." if second |
1171 | * char is also "." |
1172 | */ |
1173 | if (namlen == 1 && lfs_dir_getino(fs, dp) == ip->i_number) |
1174 | continue; |
1175 | if (name[1] == '.' && lfs_dir_getino(fs, dp) == parentino) |
1176 | continue; |
1177 | return (0); |
1178 | } |
1179 | return (1); |
1180 | } |
1181 | |
1182 | #define ULFS_DIRRABLKS 0 |
1183 | int ulfs_dirrablks = ULFS_DIRRABLKS; |
1184 | |
1185 | /* |
1186 | * ulfs_blkatoff: Return buffer with the contents of block "offset" from |
1187 | * the beginning of directory "vp". If "res" is non-NULL, fill it in with |
1188 | * a pointer to the remaining space in the directory. If the caller intends |
1189 | * to modify the buffer returned, "modify" must be true. |
1190 | */ |
1191 | |
1192 | int |
1193 | ulfs_blkatoff(struct vnode *vp, off_t offset, char **res, struct buf **bpp, |
1194 | bool modify) |
1195 | { |
1196 | struct inode *ip __diagused; |
1197 | struct buf *bp; |
1198 | daddr_t lbn; |
1199 | const int dirrablks = ulfs_dirrablks; |
1200 | daddr_t *blks; |
1201 | int *blksizes; |
1202 | int run, error; |
1203 | struct mount *mp = vp->v_mount; |
1204 | const int bshift = mp->mnt_fs_bshift; |
1205 | const int bsize = 1 << bshift; |
1206 | off_t eof; |
1207 | |
1208 | blks = kmem_alloc((1 + dirrablks) * sizeof(daddr_t), KM_SLEEP); |
1209 | blksizes = kmem_alloc((1 + dirrablks) * sizeof(int), KM_SLEEP); |
1210 | ip = VTOI(vp); |
1211 | KASSERT(vp->v_size == ip->i_size); |
1212 | GOP_SIZE(vp, vp->v_size, &eof, 0); |
1213 | lbn = offset >> bshift; |
1214 | |
1215 | for (run = 0; run <= dirrablks;) { |
1216 | const off_t curoff = lbn << bshift; |
1217 | const int size = MIN(eof - curoff, bsize); |
1218 | |
1219 | if (size == 0) { |
1220 | break; |
1221 | } |
1222 | KASSERT(curoff < eof); |
1223 | blks[run] = lbn; |
1224 | blksizes[run] = size; |
1225 | lbn++; |
1226 | run++; |
1227 | if (size != bsize) { |
1228 | break; |
1229 | } |
1230 | } |
1231 | KASSERT(run >= 1); |
1232 | error = breadn(vp, blks[0], blksizes[0], &blks[1], &blksizes[1], |
1233 | run - 1, (modify ? B_MODIFY : 0), &bp); |
1234 | if (error != 0) { |
1235 | *bpp = NULL; |
1236 | goto out; |
1237 | } |
1238 | if (res) { |
1239 | *res = (char *)bp->b_data + (offset & (bsize - 1)); |
1240 | } |
1241 | *bpp = bp; |
1242 | |
1243 | out: |
1244 | kmem_free(blks, (1 + dirrablks) * sizeof(daddr_t)); |
1245 | kmem_free(blksizes, (1 + dirrablks) * sizeof(int)); |
1246 | return error; |
1247 | } |
1248 | |