Simplify vn_lock(), VOP_LOCK(), and VOP_UNLOCK() by removing the thread_t
[dragonfly.git] / sys / vfs / isofs / cd9660 / cd9660_lookup.c
CommitLineData
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1/*-
2 * Copyright (c) 1989, 1993, 1994
3 * The Regents of the University of California. All rights reserved.
4 *
5 * This code is derived from software contributed to Berkeley
6 * by Pace Willisson (pace@blitz.com). The Rock Ridge Extension
7 * Support code is derived from software contributed to Berkeley
8 * by Atsushi Murai (amurai@spec.co.jp).
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
18 * 3. All advertising materials mentioning features or use of this software
19 * must display the following acknowledgement:
20 * This product includes software developed by the University of
21 * California, Berkeley and its contributors.
22 * 4. Neither the name of the University nor the names of its contributors
23 * may be used to endorse or promote products derived from this software
24 * without specific prior written permission.
25 *
26 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
27 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
28 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
29 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
30 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
31 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
32 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
33 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
34 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
35 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
36 * SUCH DAMAGE.
37 *
38 * from: @(#)ufs_lookup.c 7.33 (Berkeley) 5/19/91
39 *
40 * @(#)cd9660_lookup.c 8.2 (Berkeley) 1/23/94
41 * $FreeBSD: src/sys/isofs/cd9660/cd9660_lookup.c,v 1.23.2.2 2001/11/04 06:19:47 dillon Exp $
ca466bae 42 * $DragonFly: src/sys/vfs/isofs/cd9660/cd9660_lookup.c,v 1.22 2006/05/05 21:15:10 dillon Exp $
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43 */
44
45#include <sys/param.h>
46#include <sys/systm.h>
dadab5e9 47#include <sys/proc.h>
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48#include <sys/namei.h>
49#include <sys/buf.h>
50#include <sys/vnode.h>
51#include <sys/mount.h>
52
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53#include "iso.h"
54#include "cd9660_node.h"
55#include "iso_rrip.h"
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56
57/*
58 * Convert a component of a pathname into a pointer to a locked inode.
59 * This is a very central and rather complicated routine.
60 * If the file system is not maintained in a strict tree hierarchy,
61 * this can result in a deadlock situation (see comments in code below).
62 *
63 * The flag argument is LOOKUP, CREATE, RENAME, or DELETE depending on
64 * whether the name is to be looked up, created, renamed, or deleted.
65 * When CREATE, RENAME, or DELETE is specified, information usable in
66 * creating, renaming, or deleting a directory entry may be calculated.
67 * If flag has LOCKPARENT or'ed into it and the target of the pathname
68 * exists, lookup returns both the target and its parent directory locked.
69 * When creating or renaming and LOCKPARENT is specified, the target may
70 * not be ".". When deleting and LOCKPARENT is specified, the target may
71 * be "."., but the caller must check to ensure it does an vrele and iput
72 * instead of two iputs.
73 *
74 * Overall outline of ufs_lookup:
75 *
76 * search for name in directory, to found or notfound
77 * notfound:
78 * if creating, return locked directory, leaving info on available slots
79 * else return error
80 * found:
81 * if at end of path and deleting, return information to allow delete
82 * if at end of path and rewriting (RENAME and LOCKPARENT), lock target
83 * inode and return info to allow rewrite
84 * if not at end, add name to cache; if at end and neither creating
85 * nor deleting, add name to cache
86 *
87 * NOTE: (LOOKUP | LOCKPARENT) currently returns the parent inode unlocked.
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88 *
89 * cd9660_lookup(struct vnode *a_dvp, struct vnode **a_vpp,
90 * struct componentname *a_cnp)
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91 */
92int
e62afb5f 93cd9660_lookup(struct vop_old_lookup_args *ap)
984263bc 94{
3a1b0fdc 95 struct vnode *vdp; /* vnode for directory being searched */
24e51f36 96 globaldata_t gd = mycpu;
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97 struct iso_node *dp; /* inode for directory being searched */
98 struct iso_mnt *imp; /* file system that directory is in */
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99 struct buf *bp; /* a buffer of directory entries */
100 struct iso_directory_record *ep = 0;/* the current directory entry */
101 int entryoffsetinblock; /* offset of ep in bp's buffer */
102 int saveoffset = 0; /* offset of last directory entry in dir */
103 int numdirpasses; /* strategy for directory search */
104 doff_t endsearch; /* offset to end directory search */
105 struct vnode *pdp; /* saved dp during symlink work */
106 struct vnode *tdp; /* returned by cd9660_vget_internal */
107 u_long bmask; /* block offset mask */
108 int lockparent; /* 1 => lockparent flag is set */
109 int wantparent; /* 1 => wantparent or lockparent flag */
110 int error;
111 ino_t ino = 0;
112 int reclen;
113 u_short namelen;
114 int isoflags;
115 char altname[NAME_MAX];
116 int res;
117 int assoc, len;
118 char *name;
119 struct vnode **vpp = ap->a_vpp;
120 struct componentname *cnp = ap->a_cnp;
121 int flags = cnp->cn_flags;
122 int nameiop = cnp->cn_nameiop;
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123
124 bp = NULL;
125 *vpp = NULL;
126 vdp = ap->a_dvp;
127 dp = VTOI(vdp);
128 imp = dp->i_mnt;
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129 lockparent = flags & CNP_LOCKPARENT;
130 wantparent = flags & (CNP_LOCKPARENT | CNP_WANTPARENT);
131 cnp->cn_flags &= ~CNP_PDIRUNLOCK;
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132
133 /*
134 * We now have a segment name to search for, and a directory to search.
135 */
136
137 len = cnp->cn_namelen;
138 name = cnp->cn_nameptr;
139 /*
140 * A leading `=' means, we are looking for an associated file
141 */
142 if ((assoc = (imp->iso_ftype != ISO_FTYPE_RRIP && *name == ASSOCCHAR)))
143 {
144 len--;
145 name++;
146 }
147
148 /*
149 * If there is cached information on a previous search of
150 * this directory, pick up where we last left off.
151 * We cache only lookups as these are the most common
152 * and have the greatest payoff. Caching CREATE has little
153 * benefit as it usually must search the entire directory
154 * to determine that the entry does not exist. Caching the
155 * location of the last DELETE or RENAME has not reduced
156 * profiling time and hence has been removed in the interest
157 * of simplicity.
158 */
159 bmask = imp->im_bmask;
2b69e610 160 if (nameiop != NAMEI_LOOKUP || dp->i_diroff == 0 ||
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161 dp->i_diroff > dp->i_size) {
162 entryoffsetinblock = 0;
163 dp->i_offset = 0;
164 numdirpasses = 1;
165 } else {
166 dp->i_offset = dp->i_diroff;
167 if ((entryoffsetinblock = dp->i_offset & bmask) &&
899483f5 168 (error = cd9660_devblkatoff(vdp, (off_t)dp->i_offset, NULL, &bp)))
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169 return (error);
170 numdirpasses = 2;
24e51f36 171 gd->gd_nchstats->ncs_2passes++;
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172 }
173 endsearch = dp->i_size;
174
175searchloop:
176 while (dp->i_offset < endsearch) {
177 /*
178 * If offset is on a block boundary,
179 * read the next directory block.
180 * Release previous if it exists.
181 */
182 if ((dp->i_offset & bmask) == 0) {
183 if (bp != NULL)
184 brelse(bp);
185 if ((error =
899483f5 186 cd9660_devblkatoff(vdp, (off_t)dp->i_offset, NULL, &bp)) != 0)
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187 return (error);
188 entryoffsetinblock = 0;
189 }
190 /*
191 * Get pointer to next entry.
192 */
193 ep = (struct iso_directory_record *)
194 ((char *)bp->b_data + entryoffsetinblock);
195
196 reclen = isonum_711(ep->length);
197 if (reclen == 0) {
198 /* skip to next block, if any */
199 dp->i_offset =
200 (dp->i_offset & ~bmask) + imp->logical_block_size;
201 continue;
202 }
203
204 if (reclen < ISO_DIRECTORY_RECORD_SIZE)
205 /* illegal entry, stop */
206 break;
207
208 if (entryoffsetinblock + reclen > imp->logical_block_size)
209 /* entries are not allowed to cross boundaries */
210 break;
211
212 namelen = isonum_711(ep->name_len);
213 isoflags = isonum_711(imp->iso_ftype == ISO_FTYPE_HIGH_SIERRA?
214 &ep->date[6]: ep->flags);
215
216 if (reclen < ISO_DIRECTORY_RECORD_SIZE + namelen)
217 /* illegal entry, stop */
218 break;
219
220 /*
221 * Check for a name match.
222 */
223 switch (imp->iso_ftype) {
224 default:
225 if (!(isoflags & 4) == !assoc) {
226 if ((len == 1
227 && *name == '.')
2b69e610 228 || (flags & CNP_ISDOTDOT)) {
984263bc 229 if (namelen == 1
2b69e610 230 && ep->name[0] == ((flags & CNP_ISDOTDOT) ? 1 : 0)) {
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231 /*
232 * Save directory entry's inode number and
233 * release directory buffer.
234 */
235 dp->i_ino = isodirino(ep, imp);
236 goto found;
237 }
238 if (namelen != 1
239 || ep->name[0] != 0)
240 goto notfound;
241 } else if (!(res = isofncmp(name, len, ep->name, namelen, imp->joliet_level))) {
242 if (isoflags & 2)
243 ino = isodirino(ep, imp);
244 else
899483f5 245 ino = bp->b_bio1.bio_offset +
54078292 246 entryoffsetinblock;
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247 saveoffset = dp->i_offset;
248 } else if (ino)
249 goto foundino;
250#ifdef NOSORTBUG /* On some CDs directory entries are not sorted correctly */
251 else if (res < 0)
252 goto notfound;
253 else if (res > 0 && numdirpasses == 2)
254 numdirpasses++;
255#endif
256 }
257 break;
258 case ISO_FTYPE_RRIP:
259 if (isonum_711(ep->flags)&2)
260 ino = isodirino(ep, imp);
261 else
899483f5 262 ino = bp->b_bio1.bio_offset +
54078292 263 entryoffsetinblock;
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264 dp->i_ino = ino;
265 cd9660_rrip_getname(ep,altname,&namelen,&dp->i_ino,imp);
266 if (namelen == cnp->cn_namelen
267 && !bcmp(name,altname,namelen))
268 goto found;
269 ino = 0;
270 break;
271 }
272 dp->i_offset += reclen;
273 entryoffsetinblock += reclen;
274 }
275 if (ino) {
276foundino:
277 dp->i_ino = ino;
278 if (saveoffset != dp->i_offset) {
279 if (lblkno(imp, dp->i_offset) !=
280 lblkno(imp, saveoffset)) {
281 if (bp != NULL)
282 brelse(bp);
899483f5 283 if ((error = cd9660_devblkatoff(vdp,
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284 (off_t)saveoffset, NULL, &bp)) != 0)
285 return (error);
286 }
287 entryoffsetinblock = saveoffset & bmask;
288 ep = (struct iso_directory_record *)
289 ((char *)bp->b_data + entryoffsetinblock);
290 dp->i_offset = saveoffset;
291 }
292 goto found;
293 }
294notfound:
295 /*
296 * If we started in the middle of the directory and failed
297 * to find our target, we must check the beginning as well.
298 */
299 if (numdirpasses == 2) {
300 numdirpasses--;
301 dp->i_offset = 0;
302 endsearch = dp->i_diroff;
303 goto searchloop;
304 }
305 if (bp != NULL)
306 brelse(bp);
307
2b69e610 308 if (nameiop == NAMEI_CREATE || nameiop == NAMEI_RENAME)
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309 return (EROFS);
310 return (ENOENT);
311
312found:
313 if (numdirpasses == 2)
24e51f36 314 gd->gd_nchstats->ncs_pass2++;
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315
316 /*
317 * Found component in pathname.
318 * If the final component of path name, save information
319 * in the cache as to where the entry was found.
320 */
fad57d0e 321 if (nameiop == NAMEI_LOOKUP)
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322 dp->i_diroff = dp->i_offset;
323
324 /*
325 * Step through the translation in the name. We do not `iput' the
326 * directory because we may need it again if a symbolic link
327 * is relative to the current directory. Instead we save it
328 * unlocked as "pdp". We must get the target inode before unlocking
329 * the directory to insure that the inode will not be removed
330 * before we get it. We prevent deadlock by always fetching
331 * inodes from the root, moving down the directory tree. Thus
332 * when following backward pointers ".." we must unlock the
333 * parent directory before getting the requested directory.
334 * There is a potential race condition here if both the current
335 * and parent directories are removed before the `iget' for the
336 * inode associated with ".." returns. We hope that this occurs
337 * infrequently since we cannot avoid this race condition without
338 * implementing a sophisticated deadlock detection algorithm.
339 * Note also that this simple deadlock detection scheme will not
340 * work if the file system has any hard links other than ".."
341 * that point backwards in the directory structure.
342 */
343 pdp = vdp;
344 /*
345 * If ino is different from dp->i_ino,
346 * it's a relocated directory.
347 */
2b69e610 348 if (flags & CNP_ISDOTDOT) {
ca466bae 349 VOP_UNLOCK(pdp, 0); /* race to get the inode */
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350 error = cd9660_vget_internal(vdp->v_mount, dp->i_ino, &tdp,
351 dp->i_ino != ino, ep);
352 brelse(bp);
353 if (error) {
ca466bae 354 vn_lock(pdp, LK_EXCLUSIVE | LK_RETRY);
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355 return (error);
356 }
fad57d0e 357 if (lockparent) {
ca466bae 358 if ((error = vn_lock(pdp, LK_EXCLUSIVE)) != 0) {
2b69e610 359 cnp->cn_flags |= CNP_PDIRUNLOCK;
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360 vput(tdp);
361 return (error);
362 }
363 } else
2b69e610 364 cnp->cn_flags |= CNP_PDIRUNLOCK;
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365 *vpp = tdp;
366 } else if (dp->i_number == dp->i_ino) {
367 brelse(bp);
597aea93 368 vref(vdp); /* we want ourself, ie "." */
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369 *vpp = vdp;
370 } else {
371 error = cd9660_vget_internal(vdp->v_mount, dp->i_ino, &tdp,
372 dp->i_ino != ino, ep);
373 brelse(bp);
374 if (error)
375 return (error);
fad57d0e 376 if (!lockparent) {
2b69e610 377 cnp->cn_flags |= CNP_PDIRUNLOCK;
ca466bae 378 VOP_UNLOCK(pdp, 0);
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379 }
380 *vpp = tdp;
381 }
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382 return (0);
383}
384
385/*
899483f5 386 * Return a buffer with the contents of block "offset" from the beginning of
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387 * directory "ip". If "res" is non-zero, fill it in with a pointer to the
388 * remaining space in the directory.
389 */
390int
3fa8192b 391cd9660_blkatoff(struct vnode *vp, off_t offset, char **res, struct buf **bpp)
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392{
393 struct iso_node *ip;
3a1b0fdc 394 struct iso_mnt *imp;
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395 struct buf *bp;
396 daddr_t lbn;
397 int bsize, error;
398
399 ip = VTOI(vp);
400 imp = ip->i_mnt;
401 lbn = lblkno(imp, offset);
402 bsize = blksize(imp, ip, lbn);
403
54078292 404 if ((error = bread(vp, lblktooff(imp, lbn), bsize, &bp)) != 0) {
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405 brelse(bp);
406 *bpp = NULL;
407 return (error);
408 }
409
410 /*
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411 * We must BMAP the buffer because the directory code may use
412 * bio_offset to calculate the inode for certain types of directory
413 * entries. We could get away with not doing it before we
414 * VMIO-backed the directories because the buffers would get freed
415 * atomically with the invalidation of their data. But with
416 * VMIO-backed buffers the buffers may be freed and then later
417 * reconstituted - and the reconstituted buffer will have no
418 * knowledge of bio_offset.
984263bc 419 */
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420 if (bp->b_bio2.bio_offset == NOOFFSET) {
421 error = VOP_BMAP(vp, bp->b_bio1.bio_offset, NULL,
422 &bp->b_bio2.bio_offset, NULL, NULL);
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423 if (error) {
424 bp->b_error = error;
425 bp->b_flags |= B_ERROR;
426 brelse(bp);
427 *bpp = NULL;
428 return (error);
429 }
430 }
431
432 if (res)
433 *res = (char *)bp->b_data + blkoff(imp, offset);
434 *bpp = bp;
435 return (0);
436}
81b5c339 437
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438
439/*
440 * Return a buffer with the contents of block "offset" from the beginning of
441 * directory "ip". If "res" is non-zero, fill it in with a pointer to the
442 * remaining space in the directory.
443 *
444 * Use the underlying device vnode rather then the passed vnode for the
445 * buffer cache operation. This allows us to access meta-data conveniently
446 * without having to instantiate a VM object for the vnode.
447 *
448 * WARNING! Callers of this routine need to be careful when accessing
449 * the bio_offset. Since this is a device buffer, the device offset will
450 * be in bio1.bio_offset, not bio2.bio_offset.
451 */
452int
453cd9660_devblkatoff(struct vnode *vp, off_t offset, char **res, struct buf **bpp)
454{
455 struct iso_node *ip;
456 struct iso_mnt *imp;
457 struct buf *bp;
458 daddr_t lbn;
459 off_t doffset;
460 int bsize, error;
461
462 ip = VTOI(vp);
463 imp = ip->i_mnt;
464 lbn = lblkno(imp, offset);
465 bsize = blksize(imp, ip, lbn);
466
467 error = VOP_BMAP(vp, lblktooff(imp, lbn), NULL, &doffset, NULL, NULL);
468 if (error)
469 return (error);
470
471 if ((error = bread(imp->im_devvp, doffset, bsize, &bp)) != 0) {
472 brelse(bp);
473 *bpp = NULL;
474 return (error);
475 }
476 if (res)
477 *res = (char *)bp->b_data + blkoff(imp, offset);
478 *bpp = bp;
479 return (0);
480}
481