2 * Copyright (c) 1989, 1993, 1994
3 * The Regents of the University of California. All rights reserved.
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).
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11 * modification, are permitted provided that the following conditions
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
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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.
26 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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35 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
38 * from: @(#)ufs_lookup.c 7.33 (Berkeley) 5/19/91
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 $
42 * $DragonFly: src/sys/vfs/isofs/cd9660/cd9660_lookup.c,v 1.12 2004/04/24 04:32:04 drhodus Exp $
45 #include <sys/param.h>
46 #include <sys/systm.h>
48 #include <sys/namei.h>
50 #include <sys/vnode.h>
51 #include <sys/mount.h>
54 #include "cd9660_node.h"
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).
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.
74 * Overall outline of ufs_lookup:
76 * search for name in directory, to found or notfound
78 * if creating, return locked directory, leaving info on available slots
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
87 * NOTE: (LOOKUP | LOCKPARENT) currently returns the parent inode unlocked.
89 * cd9660_lookup(struct vnode *a_dvp, struct vnode **a_vpp,
90 * struct componentname *a_cnp)
93 cd9660_lookup(struct vop_cachedlookup_args *ap)
95 struct vnode *vdp; /* vnode for directory being searched */
96 globaldata_t gd = mycpu;
97 struct iso_node *dp; /* inode for directory being searched */
98 struct iso_mnt *imp; /* file system that directory is in */
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 */
115 char altname[NAME_MAX];
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;
123 struct thread *td = cnp->cn_td;
130 lockparent = flags & CNP_LOCKPARENT;
131 wantparent = flags & (CNP_LOCKPARENT | CNP_WANTPARENT);
132 cnp->cn_flags &= ~CNP_PDIRUNLOCK;
135 * We now have a segment name to search for, and a directory to search.
138 len = cnp->cn_namelen;
139 name = cnp->cn_nameptr;
141 * A leading `=' means, we are looking for an associated file
143 if ((assoc = (imp->iso_ftype != ISO_FTYPE_RRIP && *name == ASSOCCHAR)))
150 * If there is cached information on a previous search of
151 * this directory, pick up where we last left off.
152 * We cache only lookups as these are the most common
153 * and have the greatest payoff. Caching CREATE has little
154 * benefit as it usually must search the entire directory
155 * to determine that the entry does not exist. Caching the
156 * location of the last DELETE or RENAME has not reduced
157 * profiling time and hence has been removed in the interest
160 bmask = imp->im_bmask;
161 if (nameiop != NAMEI_LOOKUP || dp->i_diroff == 0 ||
162 dp->i_diroff > dp->i_size) {
163 entryoffsetinblock = 0;
167 dp->i_offset = dp->i_diroff;
168 if ((entryoffsetinblock = dp->i_offset & bmask) &&
169 (error = cd9660_blkatoff(vdp, (off_t)dp->i_offset, NULL, &bp)))
172 gd->gd_nchstats->ncs_2passes++;
174 endsearch = dp->i_size;
177 while (dp->i_offset < endsearch) {
179 * If offset is on a block boundary,
180 * read the next directory block.
181 * Release previous if it exists.
183 if ((dp->i_offset & bmask) == 0) {
187 cd9660_blkatoff(vdp, (off_t)dp->i_offset, NULL, &bp)) != 0)
189 entryoffsetinblock = 0;
192 * Get pointer to next entry.
194 ep = (struct iso_directory_record *)
195 ((char *)bp->b_data + entryoffsetinblock);
197 reclen = isonum_711(ep->length);
199 /* skip to next block, if any */
201 (dp->i_offset & ~bmask) + imp->logical_block_size;
205 if (reclen < ISO_DIRECTORY_RECORD_SIZE)
206 /* illegal entry, stop */
209 if (entryoffsetinblock + reclen > imp->logical_block_size)
210 /* entries are not allowed to cross boundaries */
213 namelen = isonum_711(ep->name_len);
214 isoflags = isonum_711(imp->iso_ftype == ISO_FTYPE_HIGH_SIERRA?
215 &ep->date[6]: ep->flags);
217 if (reclen < ISO_DIRECTORY_RECORD_SIZE + namelen)
218 /* illegal entry, stop */
222 * Check for a name match.
224 switch (imp->iso_ftype) {
226 if (!(isoflags & 4) == !assoc) {
229 || (flags & CNP_ISDOTDOT)) {
231 && ep->name[0] == ((flags & CNP_ISDOTDOT) ? 1 : 0)) {
233 * Save directory entry's inode number and
234 * release directory buffer.
236 dp->i_ino = isodirino(ep, imp);
242 } else if (!(res = isofncmp(name, len, ep->name, namelen, imp->joliet_level))) {
244 ino = isodirino(ep, imp);
246 ino = dbtob(bp->b_blkno)
247 + entryoffsetinblock;
248 saveoffset = dp->i_offset;
251 #ifdef NOSORTBUG /* On some CDs directory entries are not sorted correctly */
254 else if (res > 0 && numdirpasses == 2)
260 if (isonum_711(ep->flags)&2)
261 ino = isodirino(ep, imp);
263 ino = dbtob(bp->b_blkno) + entryoffsetinblock;
265 cd9660_rrip_getname(ep,altname,&namelen,&dp->i_ino,imp);
266 if (namelen == cnp->cn_namelen
267 && !bcmp(name,altname,namelen))
272 dp->i_offset += reclen;
273 entryoffsetinblock += reclen;
278 if (saveoffset != dp->i_offset) {
279 if (lblkno(imp, dp->i_offset) !=
280 lblkno(imp, saveoffset)) {
283 if ((error = cd9660_blkatoff(vdp,
284 (off_t)saveoffset, NULL, &bp)) != 0)
287 entryoffsetinblock = saveoffset & bmask;
288 ep = (struct iso_directory_record *)
289 ((char *)bp->b_data + entryoffsetinblock);
290 dp->i_offset = saveoffset;
296 * If we started in the middle of the directory and failed
297 * to find our target, we must check the beginning as well.
299 if (numdirpasses == 2) {
302 endsearch = dp->i_diroff;
309 * Insert name into cache (as non-existent) if appropriate.
311 if (cnp->cn_flags & CNP_MAKEENTRY)
312 cache_enter(vdp, NCPNULL, *vpp, cnp);
313 if (nameiop == NAMEI_CREATE || nameiop == NAMEI_RENAME)
318 if (numdirpasses == 2)
319 gd->gd_nchstats->ncs_pass2++;
322 * Found component in pathname.
323 * If the final component of path name, save information
324 * in the cache as to where the entry was found.
326 if ((flags & CNP_ISLASTCN) && nameiop == NAMEI_LOOKUP)
327 dp->i_diroff = dp->i_offset;
330 * Step through the translation in the name. We do not `iput' the
331 * directory because we may need it again if a symbolic link
332 * is relative to the current directory. Instead we save it
333 * unlocked as "pdp". We must get the target inode before unlocking
334 * the directory to insure that the inode will not be removed
335 * before we get it. We prevent deadlock by always fetching
336 * inodes from the root, moving down the directory tree. Thus
337 * when following backward pointers ".." we must unlock the
338 * parent directory before getting the requested directory.
339 * There is a potential race condition here if both the current
340 * and parent directories are removed before the `iget' for the
341 * inode associated with ".." returns. We hope that this occurs
342 * infrequently since we cannot avoid this race condition without
343 * implementing a sophisticated deadlock detection algorithm.
344 * Note also that this simple deadlock detection scheme will not
345 * work if the file system has any hard links other than ".."
346 * that point backwards in the directory structure.
350 * If ino is different from dp->i_ino,
351 * it's a relocated directory.
353 if (flags & CNP_ISDOTDOT) {
354 VOP_UNLOCK(pdp, NULL, 0, td); /* race to get the inode */
355 error = cd9660_vget_internal(vdp->v_mount, dp->i_ino, &tdp,
356 dp->i_ino != ino, ep);
359 vn_lock(pdp, NULL, LK_EXCLUSIVE | LK_RETRY, td);
362 if (lockparent && (flags & CNP_ISLASTCN)) {
363 if ((error = vn_lock(pdp, NULL, LK_EXCLUSIVE, td)) != 0) {
364 cnp->cn_flags |= CNP_PDIRUNLOCK;
369 cnp->cn_flags |= CNP_PDIRUNLOCK;
371 } else if (dp->i_number == dp->i_ino) {
373 vref(vdp); /* we want ourself, ie "." */
376 error = cd9660_vget_internal(vdp->v_mount, dp->i_ino, &tdp,
377 dp->i_ino != ino, ep);
381 if (!lockparent || !(flags & CNP_ISLASTCN)) {
382 cnp->cn_flags |= CNP_PDIRUNLOCK;
383 VOP_UNLOCK(pdp, NULL, 0, td);
389 * Insert name into cache if appropriate.
391 if (cnp->cn_flags & CNP_MAKEENTRY)
392 cache_enter(vdp, NCPNULL, *vpp, cnp);
397 * Return buffer with the contents of block "offset" from the beginning of
398 * directory "ip". If "res" is non-zero, fill it in with a pointer to the
399 * remaining space in the directory.
402 cd9660_blkatoff(struct vnode *vp, off_t offset, char **res, struct buf **bpp)
412 lbn = lblkno(imp, offset);
413 bsize = blksize(imp, ip, lbn);
415 if ((error = bread(vp, lbn, bsize, &bp)) != 0) {
422 * We must BMAP the buffer because the directory code may use b_blkno
423 * to calculate the inode for certain types of directory entries.
424 * We could get away with not doing it before we VMIO-backed the
425 * directories because the buffers would get freed atomically with
426 * the invalidation of their data. But with VMIO-backed buffers
427 * the buffers may be freed and then later reconstituted - and the
428 * reconstituted buffer will have no knowledge of b_blkno.
430 if (bp->b_blkno == bp->b_lblkno) {
431 error = VOP_BMAP(vp, bp->b_lblkno, NULL,
432 &bp->b_blkno, NULL, NULL);
435 bp->b_flags |= B_ERROR;
443 *res = (char *)bp->b_data + blkoff(imp, offset);