2 * SPDX-License-Identifier: BSD-3-Clause
4 * Copyright (c) 1989, 1993, 1995
5 * The Regents of the University of California. All rights reserved.
7 * This code is derived from software contributed to Berkeley by
8 * Poul-Henning Kamp of the FreeBSD Project.
10 * Redistribution and use in source and binary forms, with or without
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.
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. Neither the name of the University nor the names of its contributors
19 * may be used to endorse or promote products derived from this software
20 * without specific prior written permission.
22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34 * @(#)vfs_cache.c 8.5 (Berkeley) 3/22/95
37 #include <sys/cdefs.h>
38 __FBSDID("$FreeBSD$");
41 #include "opt_ktrace.h"
43 #include <sys/param.h>
44 #include <sys/systm.h>
45 #include <sys/counter.h>
46 #include <sys/filedesc.h>
47 #include <sys/fnv_hash.h>
48 #include <sys/kernel.h>
51 #include <sys/malloc.h>
52 #include <sys/fcntl.h>
53 #include <sys/mount.h>
54 #include <sys/namei.h>
56 #include <sys/rwlock.h>
59 #include <sys/syscallsubr.h>
60 #include <sys/sysctl.h>
61 #include <sys/sysproto.h>
62 #include <sys/vnode.h>
64 #include <sys/ktrace.h>
73 SDT_PROVIDER_DECLARE(vfs);
74 SDT_PROBE_DEFINE3(vfs, namecache, enter, done, "struct vnode *", "char *",
76 SDT_PROBE_DEFINE2(vfs, namecache, enter_negative, done, "struct vnode *",
78 SDT_PROBE_DEFINE1(vfs, namecache, fullpath, entry, "struct vnode *");
79 SDT_PROBE_DEFINE3(vfs, namecache, fullpath, hit, "struct vnode *",
80 "char *", "struct vnode *");
81 SDT_PROBE_DEFINE1(vfs, namecache, fullpath, miss, "struct vnode *");
82 SDT_PROBE_DEFINE3(vfs, namecache, fullpath, return, "int",
83 "struct vnode *", "char *");
84 SDT_PROBE_DEFINE3(vfs, namecache, lookup, hit, "struct vnode *", "char *",
86 SDT_PROBE_DEFINE2(vfs, namecache, lookup, hit__negative,
87 "struct vnode *", "char *");
88 SDT_PROBE_DEFINE2(vfs, namecache, lookup, miss, "struct vnode *",
90 SDT_PROBE_DEFINE1(vfs, namecache, purge, done, "struct vnode *");
91 SDT_PROBE_DEFINE1(vfs, namecache, purge_negative, done, "struct vnode *");
92 SDT_PROBE_DEFINE1(vfs, namecache, purgevfs, done, "struct mount *");
93 SDT_PROBE_DEFINE3(vfs, namecache, zap, done, "struct vnode *", "char *",
95 SDT_PROBE_DEFINE3(vfs, namecache, zap_negative, done, "struct vnode *",
97 SDT_PROBE_DEFINE3(vfs, namecache, shrink_negative, done, "struct vnode *",
101 * This structure describes the elements in the cache of recent
102 * names looked up by namei.
106 LIST_ENTRY(namecache) nc_hash; /* hash chain */
107 LIST_ENTRY(namecache) nc_src; /* source vnode list */
108 TAILQ_ENTRY(namecache) nc_dst; /* destination vnode list */
109 struct vnode *nc_dvp; /* vnode of parent of name */
111 struct vnode *nu_vp; /* vnode the name refers to */
112 u_int nu_neghits; /* negative entry hits */
114 u_char nc_flag; /* flag bits */
115 u_char nc_nlen; /* length of name */
116 char nc_name[0]; /* segment name + nul */
120 * struct namecache_ts repeats struct namecache layout up to the
122 * struct namecache_ts is used in place of struct namecache when time(s) need
123 * to be stored. The nc_dotdottime field is used when a cache entry is mapping
124 * both a non-dotdot directory name plus dotdot for the directory's
127 struct namecache_ts {
128 struct timespec nc_time; /* timespec provided by fs */
129 struct timespec nc_dotdottime; /* dotdot timespec provided by fs */
130 int nc_ticks; /* ticks value when entry was added */
131 struct namecache nc_nc;
134 #define nc_vp n_un.nu_vp
135 #define nc_neghits n_un.nu_neghits
138 * Flags in namecache.nc_flag
140 #define NCF_WHITE 0x01
141 #define NCF_ISDOTDOT 0x02
144 #define NCF_DVDROP 0x10
145 #define NCF_NEGATIVE 0x20
146 #define NCF_HOTNEGATIVE 0x40
149 * Name caching works as follows:
151 * Names found by directory scans are retained in a cache
152 * for future reference. It is managed LRU, so frequently
153 * used names will hang around. Cache is indexed by hash value
154 * obtained from (dvp, name) where dvp refers to the directory
157 * If it is a "negative" entry, (i.e. for a name that is known NOT to
158 * exist) the vnode pointer will be NULL.
160 * Upon reaching the last segment of a path, if the reference
161 * is for DELETE, or NOCACHE is set (rewrite), and the
162 * name is located in the cache, it will be dropped.
164 * These locks are used (in the order in which they can be taken):
166 * vnodelock mtx vnode lists and v_cache_dd field protection
167 * bucketlock rwlock for access to given set of hash buckets
168 * neglist mtx negative entry LRU management
170 * Additionally, ncneg_shrink_lock mtx is used to have at most one thread
171 * shrinking the LRU list.
173 * It is legal to take multiple vnodelock and bucketlock locks. The locking
174 * order is lower address first. Both are recursive.
176 * "." lookups are lockless.
178 * ".." and vnode -> name lookups require vnodelock.
180 * name -> vnode lookup requires the relevant bucketlock to be held for reading.
182 * Insertions and removals of entries require involved vnodes and bucketlocks
183 * to be write-locked to prevent other threads from seeing the entry.
185 * Some lookups result in removal of the found entry (e.g. getting rid of a
186 * negative entry with the intent to create a positive one), which poses a
187 * problem when multiple threads reach the state. Similarly, two different
188 * threads can purge two different vnodes and try to remove the same name.
190 * If the already held vnode lock is lower than the second required lock, we
191 * can just take the other lock. However, in the opposite case, this could
192 * deadlock. As such, this is resolved by trylocking and if that fails unlocking
193 * the first node, locking everything in order and revalidating the state.
197 * Structures associated with name caching.
199 #define NCHHASH(hash) \
200 (&nchashtbl[(hash) & nchash])
201 static __read_mostly LIST_HEAD(nchashhead, namecache) *nchashtbl;/* Hash Table */
202 static u_long __read_mostly nchash; /* size of hash table */
203 SYSCTL_ULONG(_debug, OID_AUTO, nchash, CTLFLAG_RD, &nchash, 0,
204 "Size of namecache hash table");
205 static u_long __read_mostly ncnegfactor = 12; /* ratio of negative entries */
206 SYSCTL_ULONG(_vfs, OID_AUTO, ncnegfactor, CTLFLAG_RW, &ncnegfactor, 0,
207 "Ratio of negative namecache entries");
208 static u_long __exclusive_cache_line numneg; /* number of negative entries allocated */
209 SYSCTL_ULONG(_debug, OID_AUTO, numneg, CTLFLAG_RD, &numneg, 0,
210 "Number of negative entries in namecache");
211 static u_long __exclusive_cache_line numcache;/* number of cache entries allocated */
212 SYSCTL_ULONG(_debug, OID_AUTO, numcache, CTLFLAG_RD, &numcache, 0,
213 "Number of namecache entries");
214 static u_long __exclusive_cache_line numcachehv;/* number of cache entries with vnodes held */
215 SYSCTL_ULONG(_debug, OID_AUTO, numcachehv, CTLFLAG_RD, &numcachehv, 0,
216 "Number of namecache entries with vnodes held");
217 u_int __read_mostly ncsizefactor = 2;
218 SYSCTL_UINT(_vfs, OID_AUTO, ncsizefactor, CTLFLAG_RW, &ncsizefactor, 0,
219 "Size factor for namecache");
220 static u_int __read_mostly ncpurgeminvnodes;
221 SYSCTL_UINT(_vfs, OID_AUTO, ncpurgeminvnodes, CTLFLAG_RW, &ncpurgeminvnodes, 0,
222 "Number of vnodes below which purgevfs ignores the request");
223 static u_int __read_mostly ncneghitsrequeue = 8;
224 SYSCTL_UINT(_vfs, OID_AUTO, ncneghitsrequeue, CTLFLAG_RW, &ncneghitsrequeue, 0,
225 "Number of hits to requeue a negative entry in the LRU list");
227 struct nchstats nchstats; /* cache effectiveness statistics */
229 static struct mtx ncneg_shrink_lock;
230 static int shrink_list_turn;
234 TAILQ_HEAD(, namecache) nl_list;
235 } __aligned(CACHE_LINE_SIZE);
237 static struct neglist __read_mostly *neglists;
238 static struct neglist ncneg_hot;
240 #define numneglists (ncneghash + 1)
241 static u_int __read_mostly ncneghash;
242 static inline struct neglist *
243 NCP2NEGLIST(struct namecache *ncp)
246 return (&neglists[(((uintptr_t)(ncp) >> 8) & ncneghash)]);
249 #define numbucketlocks (ncbuckethash + 1)
250 static u_int __read_mostly ncbuckethash;
251 static struct rwlock_padalign __read_mostly *bucketlocks;
252 #define HASH2BUCKETLOCK(hash) \
253 ((struct rwlock *)(&bucketlocks[((hash) & ncbuckethash)]))
255 #define numvnodelocks (ncvnodehash + 1)
256 static u_int __read_mostly ncvnodehash;
257 static struct mtx __read_mostly *vnodelocks;
258 static inline struct mtx *
259 VP2VNODELOCK(struct vnode *vp)
262 return (&vnodelocks[(((uintptr_t)(vp) >> 8) & ncvnodehash)]);
266 * UMA zones for the VFS cache.
268 * The small cache is used for entries with short names, which are the
269 * most common. The large cache is used for entries which are too big to
270 * fit in the small cache.
272 static uma_zone_t __read_mostly cache_zone_small;
273 static uma_zone_t __read_mostly cache_zone_small_ts;
274 static uma_zone_t __read_mostly cache_zone_large;
275 static uma_zone_t __read_mostly cache_zone_large_ts;
277 #define CACHE_PATH_CUTOFF 35
279 static struct namecache *
280 cache_alloc(int len, int ts)
282 struct namecache_ts *ncp_ts;
283 struct namecache *ncp;
285 if (__predict_false(ts)) {
286 if (len <= CACHE_PATH_CUTOFF)
287 ncp_ts = uma_zalloc(cache_zone_small_ts, M_WAITOK);
289 ncp_ts = uma_zalloc(cache_zone_large_ts, M_WAITOK);
290 ncp = &ncp_ts->nc_nc;
292 if (len <= CACHE_PATH_CUTOFF)
293 ncp = uma_zalloc(cache_zone_small, M_WAITOK);
295 ncp = uma_zalloc(cache_zone_large, M_WAITOK);
301 cache_free(struct namecache *ncp)
303 struct namecache_ts *ncp_ts;
307 if ((ncp->nc_flag & NCF_DVDROP) != 0)
309 if (__predict_false(ncp->nc_flag & NCF_TS)) {
310 ncp_ts = __containerof(ncp, struct namecache_ts, nc_nc);
311 if (ncp->nc_nlen <= CACHE_PATH_CUTOFF)
312 uma_zfree(cache_zone_small_ts, ncp_ts);
314 uma_zfree(cache_zone_large_ts, ncp_ts);
316 if (ncp->nc_nlen <= CACHE_PATH_CUTOFF)
317 uma_zfree(cache_zone_small, ncp);
319 uma_zfree(cache_zone_large, ncp);
324 cache_out_ts(struct namecache *ncp, struct timespec *tsp, int *ticksp)
326 struct namecache_ts *ncp_ts;
328 KASSERT((ncp->nc_flag & NCF_TS) != 0 ||
329 (tsp == NULL && ticksp == NULL),
332 if (tsp == NULL && ticksp == NULL)
335 ncp_ts = __containerof(ncp, struct namecache_ts, nc_nc);
337 *tsp = ncp_ts->nc_time;
339 *ticksp = ncp_ts->nc_ticks;
342 static int __read_mostly doingcache = 1; /* 1 => enable the cache */
343 SYSCTL_INT(_debug, OID_AUTO, vfscache, CTLFLAG_RW, &doingcache, 0,
344 "VFS namecache enabled");
346 /* Export size information to userland */
347 SYSCTL_INT(_debug_sizeof, OID_AUTO, namecache, CTLFLAG_RD, SYSCTL_NULL_INT_PTR,
348 sizeof(struct namecache), "sizeof(struct namecache)");
351 * The new name cache statistics
353 static SYSCTL_NODE(_vfs, OID_AUTO, cache, CTLFLAG_RW, 0,
354 "Name cache statistics");
355 #define STATNODE_ULONG(name, descr) \
356 SYSCTL_ULONG(_vfs_cache, OID_AUTO, name, CTLFLAG_RD, &name, 0, descr);
357 #define STATNODE_COUNTER(name, descr) \
358 static counter_u64_t __read_mostly name; \
359 SYSCTL_COUNTER_U64(_vfs_cache, OID_AUTO, name, CTLFLAG_RD, &name, descr);
360 STATNODE_ULONG(numneg, "Number of negative cache entries");
361 STATNODE_ULONG(numcache, "Number of cache entries");
362 STATNODE_COUNTER(numcalls, "Number of cache lookups");
363 STATNODE_COUNTER(dothits, "Number of '.' hits");
364 STATNODE_COUNTER(dotdothits, "Number of '..' hits");
365 STATNODE_COUNTER(numchecks, "Number of checks in lookup");
366 STATNODE_COUNTER(nummiss, "Number of cache misses");
367 STATNODE_COUNTER(nummisszap, "Number of cache misses we do not want to cache");
368 STATNODE_COUNTER(numposzaps,
369 "Number of cache hits (positive) we do not want to cache");
370 STATNODE_COUNTER(numposhits, "Number of cache hits (positive)");
371 STATNODE_COUNTER(numnegzaps,
372 "Number of cache hits (negative) we do not want to cache");
373 STATNODE_COUNTER(numneghits, "Number of cache hits (negative)");
374 /* These count for kern___getcwd(), too. */
375 STATNODE_COUNTER(numfullpathcalls, "Number of fullpath search calls");
376 STATNODE_COUNTER(numfullpathfail1, "Number of fullpath search errors (ENOTDIR)");
377 STATNODE_COUNTER(numfullpathfail2,
378 "Number of fullpath search errors (VOP_VPTOCNP failures)");
379 STATNODE_COUNTER(numfullpathfail4, "Number of fullpath search errors (ENOMEM)");
380 STATNODE_COUNTER(numfullpathfound, "Number of successful fullpath calls");
381 STATNODE_COUNTER(zap_and_exit_bucket_relock_success,
382 "Number of successful removals after relocking");
383 static long zap_and_exit_bucket_fail; STATNODE_ULONG(zap_and_exit_bucket_fail,
384 "Number of times zap_and_exit failed to lock");
385 static long zap_and_exit_bucket_fail2; STATNODE_ULONG(zap_and_exit_bucket_fail2,
386 "Number of times zap_and_exit failed to lock");
387 static long cache_lock_vnodes_cel_3_failures;
388 STATNODE_ULONG(cache_lock_vnodes_cel_3_failures,
389 "Number of times 3-way vnode locking failed");
391 static void cache_zap_locked(struct namecache *ncp, bool neg_locked);
392 static int vn_fullpath1(struct thread *td, struct vnode *vp, struct vnode *rdir,
393 char *buf, char **retbuf, u_int buflen);
395 static MALLOC_DEFINE(M_VFSCACHE, "vfscache", "VFS name cache entries");
397 static int cache_yield;
398 SYSCTL_INT(_vfs_cache, OID_AUTO, yield, CTLFLAG_RD, &cache_yield, 0,
399 "Number of times cache called yield");
401 static void __noinline
402 cache_maybe_yield(void)
405 if (should_yield()) {
407 kern_yield(PRI_USER);
412 cache_assert_vlp_locked(struct mtx *vlp)
416 mtx_assert(vlp, MA_OWNED);
420 cache_assert_vnode_locked(struct vnode *vp)
424 vlp = VP2VNODELOCK(vp);
425 cache_assert_vlp_locked(vlp);
429 cache_get_hash(char *name, u_char len, struct vnode *dvp)
433 hash = fnv_32_buf(name, len, FNV1_32_INIT);
434 hash = fnv_32_buf(&dvp, sizeof(dvp), hash);
438 static inline struct rwlock *
439 NCP2BUCKETLOCK(struct namecache *ncp)
443 hash = cache_get_hash(ncp->nc_name, ncp->nc_nlen, ncp->nc_dvp);
444 return (HASH2BUCKETLOCK(hash));
449 cache_assert_bucket_locked(struct namecache *ncp, int mode)
453 blp = NCP2BUCKETLOCK(ncp);
454 rw_assert(blp, mode);
457 #define cache_assert_bucket_locked(x, y) do { } while (0)
460 #define cache_sort_vnodes(x, y) _cache_sort_vnodes((void **)(x), (void **)(y))
462 _cache_sort_vnodes(void **p1, void **p2)
466 MPASS(*p1 != NULL || *p2 != NULL);
476 cache_lock_all_buckets(void)
480 for (i = 0; i < numbucketlocks; i++)
481 rw_wlock(&bucketlocks[i]);
485 cache_unlock_all_buckets(void)
489 for (i = 0; i < numbucketlocks; i++)
490 rw_wunlock(&bucketlocks[i]);
494 cache_lock_all_vnodes(void)
498 for (i = 0; i < numvnodelocks; i++)
499 mtx_lock(&vnodelocks[i]);
503 cache_unlock_all_vnodes(void)
507 for (i = 0; i < numvnodelocks; i++)
508 mtx_unlock(&vnodelocks[i]);
512 cache_trylock_vnodes(struct mtx *vlp1, struct mtx *vlp2)
515 cache_sort_vnodes(&vlp1, &vlp2);
518 if (!mtx_trylock(vlp1))
521 if (!mtx_trylock(vlp2)) {
531 cache_lock_vnodes(struct mtx *vlp1, struct mtx *vlp2)
534 MPASS(vlp1 != NULL || vlp2 != NULL);
544 cache_unlock_vnodes(struct mtx *vlp1, struct mtx *vlp2)
547 MPASS(vlp1 != NULL || vlp2 != NULL);
556 sysctl_nchstats(SYSCTL_HANDLER_ARGS)
558 struct nchstats snap;
560 if (req->oldptr == NULL)
561 return (SYSCTL_OUT(req, 0, sizeof(snap)));
564 snap.ncs_goodhits = counter_u64_fetch(numposhits);
565 snap.ncs_neghits = counter_u64_fetch(numneghits);
566 snap.ncs_badhits = counter_u64_fetch(numposzaps) +
567 counter_u64_fetch(numnegzaps);
568 snap.ncs_miss = counter_u64_fetch(nummisszap) +
569 counter_u64_fetch(nummiss);
571 return (SYSCTL_OUT(req, &snap, sizeof(snap)));
573 SYSCTL_PROC(_vfs_cache, OID_AUTO, nchstats, CTLTYPE_OPAQUE | CTLFLAG_RD |
574 CTLFLAG_MPSAFE, 0, 0, sysctl_nchstats, "LU",
575 "VFS cache effectiveness statistics");
579 * Grab an atomic snapshot of the name cache hash chain lengths
581 static SYSCTL_NODE(_debug, OID_AUTO, hashstat, CTLFLAG_RW, NULL,
585 sysctl_debug_hashstat_rawnchash(SYSCTL_HANDLER_ARGS)
587 struct nchashhead *ncpp;
588 struct namecache *ncp;
589 int i, error, n_nchash, *cntbuf;
592 n_nchash = nchash + 1; /* nchash is max index, not count */
593 if (req->oldptr == NULL)
594 return SYSCTL_OUT(req, 0, n_nchash * sizeof(int));
595 cntbuf = malloc(n_nchash * sizeof(int), M_TEMP, M_ZERO | M_WAITOK);
596 cache_lock_all_buckets();
597 if (n_nchash != nchash + 1) {
598 cache_unlock_all_buckets();
599 free(cntbuf, M_TEMP);
602 /* Scan hash tables counting entries */
603 for (ncpp = nchashtbl, i = 0; i < n_nchash; ncpp++, i++)
604 LIST_FOREACH(ncp, ncpp, nc_hash)
606 cache_unlock_all_buckets();
607 for (error = 0, i = 0; i < n_nchash; i++)
608 if ((error = SYSCTL_OUT(req, &cntbuf[i], sizeof(int))) != 0)
610 free(cntbuf, M_TEMP);
613 SYSCTL_PROC(_debug_hashstat, OID_AUTO, rawnchash, CTLTYPE_INT|CTLFLAG_RD|
614 CTLFLAG_MPSAFE, 0, 0, sysctl_debug_hashstat_rawnchash, "S,int",
615 "nchash chain lengths");
618 sysctl_debug_hashstat_nchash(SYSCTL_HANDLER_ARGS)
621 struct nchashhead *ncpp;
622 struct namecache *ncp;
624 int count, maxlength, used, pct;
627 return SYSCTL_OUT(req, 0, 4 * sizeof(int));
629 cache_lock_all_buckets();
630 n_nchash = nchash + 1; /* nchash is max index, not count */
634 /* Scan hash tables for applicable entries */
635 for (ncpp = nchashtbl; n_nchash > 0; n_nchash--, ncpp++) {
637 LIST_FOREACH(ncp, ncpp, nc_hash) {
642 if (maxlength < count)
645 n_nchash = nchash + 1;
646 cache_unlock_all_buckets();
647 pct = (used * 100) / (n_nchash / 100);
648 error = SYSCTL_OUT(req, &n_nchash, sizeof(n_nchash));
651 error = SYSCTL_OUT(req, &used, sizeof(used));
654 error = SYSCTL_OUT(req, &maxlength, sizeof(maxlength));
657 error = SYSCTL_OUT(req, &pct, sizeof(pct));
662 SYSCTL_PROC(_debug_hashstat, OID_AUTO, nchash, CTLTYPE_INT|CTLFLAG_RD|
663 CTLFLAG_MPSAFE, 0, 0, sysctl_debug_hashstat_nchash, "I",
664 "nchash statistics (number of total/used buckets, maximum chain length, usage percentage)");
668 * Negative entries management
670 * A variation of LRU scheme is used. New entries are hashed into one of
671 * numneglists cold lists. Entries get promoted to the hot list on first hit.
672 * Partial LRU for the hot list is maintained by requeueing them every
673 * ncneghitsrequeue hits.
675 * The shrinker will demote hot list head and evict from the cold list in a
676 * round-robin manner.
679 cache_negative_hit(struct namecache *ncp)
681 struct neglist *neglist;
684 MPASS(ncp->nc_flag & NCF_NEGATIVE);
685 hits = atomic_fetchadd_int(&ncp->nc_neghits, 1);
686 if (ncp->nc_flag & NCF_HOTNEGATIVE) {
687 if ((hits % ncneghitsrequeue) != 0)
689 mtx_lock(&ncneg_hot.nl_lock);
690 if (ncp->nc_flag & NCF_HOTNEGATIVE) {
691 TAILQ_REMOVE(&ncneg_hot.nl_list, ncp, nc_dst);
692 TAILQ_INSERT_TAIL(&ncneg_hot.nl_list, ncp, nc_dst);
693 mtx_unlock(&ncneg_hot.nl_lock);
697 * The shrinker cleared the flag and removed the entry from
698 * the hot list. Put it back.
701 mtx_lock(&ncneg_hot.nl_lock);
703 neglist = NCP2NEGLIST(ncp);
704 mtx_lock(&neglist->nl_lock);
705 if (!(ncp->nc_flag & NCF_HOTNEGATIVE)) {
706 TAILQ_REMOVE(&neglist->nl_list, ncp, nc_dst);
707 TAILQ_INSERT_TAIL(&ncneg_hot.nl_list, ncp, nc_dst);
708 ncp->nc_flag |= NCF_HOTNEGATIVE;
710 mtx_unlock(&neglist->nl_lock);
711 mtx_unlock(&ncneg_hot.nl_lock);
715 cache_negative_insert(struct namecache *ncp, bool neg_locked)
717 struct neglist *neglist;
719 MPASS(ncp->nc_flag & NCF_NEGATIVE);
720 cache_assert_bucket_locked(ncp, RA_WLOCKED);
721 neglist = NCP2NEGLIST(ncp);
723 mtx_lock(&neglist->nl_lock);
725 mtx_assert(&neglist->nl_lock, MA_OWNED);
727 TAILQ_INSERT_TAIL(&neglist->nl_list, ncp, nc_dst);
729 mtx_unlock(&neglist->nl_lock);
730 atomic_add_rel_long(&numneg, 1);
734 cache_negative_remove(struct namecache *ncp, bool neg_locked)
736 struct neglist *neglist;
737 bool hot_locked = false;
738 bool list_locked = false;
740 MPASS(ncp->nc_flag & NCF_NEGATIVE);
741 cache_assert_bucket_locked(ncp, RA_WLOCKED);
742 neglist = NCP2NEGLIST(ncp);
744 if (ncp->nc_flag & NCF_HOTNEGATIVE) {
746 mtx_lock(&ncneg_hot.nl_lock);
747 if (!(ncp->nc_flag & NCF_HOTNEGATIVE)) {
749 mtx_lock(&neglist->nl_lock);
753 mtx_lock(&neglist->nl_lock);
756 if (ncp->nc_flag & NCF_HOTNEGATIVE) {
757 mtx_assert(&ncneg_hot.nl_lock, MA_OWNED);
758 TAILQ_REMOVE(&ncneg_hot.nl_list, ncp, nc_dst);
760 mtx_assert(&neglist->nl_lock, MA_OWNED);
761 TAILQ_REMOVE(&neglist->nl_list, ncp, nc_dst);
764 mtx_unlock(&neglist->nl_lock);
766 mtx_unlock(&ncneg_hot.nl_lock);
767 atomic_subtract_rel_long(&numneg, 1);
771 cache_negative_shrink_select(int start, struct namecache **ncpp,
772 struct neglist **neglistpp)
774 struct neglist *neglist;
775 struct namecache *ncp;
781 for (i = start; i < numneglists; i++) {
782 neglist = &neglists[i];
783 if (TAILQ_FIRST(&neglist->nl_list) == NULL)
785 mtx_lock(&neglist->nl_lock);
786 ncp = TAILQ_FIRST(&neglist->nl_list);
789 mtx_unlock(&neglist->nl_lock);
792 *neglistpp = neglist;
797 cache_negative_zap_one(void)
799 struct namecache *ncp, *ncp2;
800 struct neglist *neglist;
804 if (!mtx_trylock(&ncneg_shrink_lock))
807 mtx_lock(&ncneg_hot.nl_lock);
808 ncp = TAILQ_FIRST(&ncneg_hot.nl_list);
810 neglist = NCP2NEGLIST(ncp);
811 mtx_lock(&neglist->nl_lock);
812 TAILQ_REMOVE(&ncneg_hot.nl_list, ncp, nc_dst);
813 TAILQ_INSERT_TAIL(&neglist->nl_list, ncp, nc_dst);
814 ncp->nc_flag &= ~NCF_HOTNEGATIVE;
815 mtx_unlock(&neglist->nl_lock);
818 cache_negative_shrink_select(shrink_list_turn, &ncp, &neglist);
820 if (shrink_list_turn == numneglists)
821 shrink_list_turn = 0;
822 if (ncp == NULL && shrink_list_turn == 0)
823 cache_negative_shrink_select(shrink_list_turn, &ncp, &neglist);
825 mtx_unlock(&ncneg_hot.nl_lock);
829 MPASS(ncp->nc_flag & NCF_NEGATIVE);
830 dvlp = VP2VNODELOCK(ncp->nc_dvp);
831 blp = NCP2BUCKETLOCK(ncp);
832 mtx_unlock(&neglist->nl_lock);
833 mtx_unlock(&ncneg_hot.nl_lock);
836 mtx_lock(&neglist->nl_lock);
837 ncp2 = TAILQ_FIRST(&neglist->nl_list);
838 if (ncp != ncp2 || dvlp != VP2VNODELOCK(ncp2->nc_dvp) ||
839 blp != NCP2BUCKETLOCK(ncp2) || !(ncp2->nc_flag & NCF_NEGATIVE)) {
843 SDT_PROBE3(vfs, namecache, shrink_negative, done, ncp->nc_dvp,
844 ncp->nc_name, ncp->nc_neghits);
846 cache_zap_locked(ncp, true);
848 mtx_unlock(&neglist->nl_lock);
852 mtx_unlock(&ncneg_shrink_lock);
857 * cache_zap_locked():
859 * Removes a namecache entry from cache, whether it contains an actual
860 * pointer to a vnode or if it is just a negative cache entry.
863 cache_zap_locked(struct namecache *ncp, bool neg_locked)
866 if (!(ncp->nc_flag & NCF_NEGATIVE))
867 cache_assert_vnode_locked(ncp->nc_vp);
868 cache_assert_vnode_locked(ncp->nc_dvp);
869 cache_assert_bucket_locked(ncp, RA_WLOCKED);
871 CTR2(KTR_VFS, "cache_zap(%p) vp %p", ncp,
872 (ncp->nc_flag & NCF_NEGATIVE) ? NULL : ncp->nc_vp);
873 LIST_REMOVE(ncp, nc_hash);
874 if (!(ncp->nc_flag & NCF_NEGATIVE)) {
875 SDT_PROBE3(vfs, namecache, zap, done, ncp->nc_dvp,
876 ncp->nc_name, ncp->nc_vp);
877 TAILQ_REMOVE(&ncp->nc_vp->v_cache_dst, ncp, nc_dst);
878 if (ncp == ncp->nc_vp->v_cache_dd)
879 ncp->nc_vp->v_cache_dd = NULL;
881 SDT_PROBE3(vfs, namecache, zap_negative, done, ncp->nc_dvp,
882 ncp->nc_name, ncp->nc_neghits);
883 cache_negative_remove(ncp, neg_locked);
885 if (ncp->nc_flag & NCF_ISDOTDOT) {
886 if (ncp == ncp->nc_dvp->v_cache_dd)
887 ncp->nc_dvp->v_cache_dd = NULL;
889 LIST_REMOVE(ncp, nc_src);
890 if (LIST_EMPTY(&ncp->nc_dvp->v_cache_src)) {
891 ncp->nc_flag |= NCF_DVDROP;
892 atomic_subtract_rel_long(&numcachehv, 1);
895 atomic_subtract_rel_long(&numcache, 1);
899 cache_zap_negative_locked_vnode_kl(struct namecache *ncp, struct vnode *vp)
903 MPASS(ncp->nc_dvp == vp);
904 MPASS(ncp->nc_flag & NCF_NEGATIVE);
905 cache_assert_vnode_locked(vp);
907 blp = NCP2BUCKETLOCK(ncp);
909 cache_zap_locked(ncp, false);
914 cache_zap_locked_vnode_kl2(struct namecache *ncp, struct vnode *vp,
917 struct mtx *pvlp, *vlp1, *vlp2, *to_unlock;
920 MPASS(vp == ncp->nc_dvp || vp == ncp->nc_vp);
921 cache_assert_vnode_locked(vp);
923 if (ncp->nc_flag & NCF_NEGATIVE) {
928 cache_zap_negative_locked_vnode_kl(ncp, vp);
932 pvlp = VP2VNODELOCK(vp);
933 blp = NCP2BUCKETLOCK(ncp);
934 vlp1 = VP2VNODELOCK(ncp->nc_dvp);
935 vlp2 = VP2VNODELOCK(ncp->nc_vp);
937 if (*vlpp == vlp1 || *vlpp == vlp2) {
945 cache_sort_vnodes(&vlp1, &vlp2);
950 if (!mtx_trylock(vlp1))
956 cache_zap_locked(ncp, false);
958 if (to_unlock != NULL)
959 mtx_unlock(to_unlock);
966 MPASS(*vlpp == NULL);
971 static int __noinline
972 cache_zap_locked_vnode(struct namecache *ncp, struct vnode *vp)
974 struct mtx *pvlp, *vlp1, *vlp2, *to_unlock;
978 MPASS(vp == ncp->nc_dvp || vp == ncp->nc_vp);
979 cache_assert_vnode_locked(vp);
981 pvlp = VP2VNODELOCK(vp);
982 if (ncp->nc_flag & NCF_NEGATIVE) {
983 cache_zap_negative_locked_vnode_kl(ncp, vp);
987 blp = NCP2BUCKETLOCK(ncp);
988 vlp1 = VP2VNODELOCK(ncp->nc_dvp);
989 vlp2 = VP2VNODELOCK(ncp->nc_vp);
990 cache_sort_vnodes(&vlp1, &vlp2);
995 if (!mtx_trylock(vlp1)) {
1002 cache_zap_locked(ncp, false);
1004 mtx_unlock(to_unlock);
1011 * If trylocking failed we can get here. We know enough to take all needed locks
1012 * in the right order and re-lookup the entry.
1015 cache_zap_unlocked_bucket(struct namecache *ncp, struct componentname *cnp,
1016 struct vnode *dvp, struct mtx *dvlp, struct mtx *vlp, uint32_t hash,
1019 struct namecache *rncp;
1021 cache_assert_bucket_locked(ncp, RA_UNLOCKED);
1023 cache_sort_vnodes(&dvlp, &vlp);
1024 cache_lock_vnodes(dvlp, vlp);
1026 LIST_FOREACH(rncp, (NCHHASH(hash)), nc_hash) {
1027 if (rncp == ncp && rncp->nc_dvp == dvp &&
1028 rncp->nc_nlen == cnp->cn_namelen &&
1029 !bcmp(rncp->nc_name, cnp->cn_nameptr, rncp->nc_nlen))
1033 cache_zap_locked(rncp, false);
1035 cache_unlock_vnodes(dvlp, vlp);
1036 counter_u64_add(zap_and_exit_bucket_relock_success, 1);
1041 cache_unlock_vnodes(dvlp, vlp);
1045 static int __noinline
1046 cache_zap_wlocked_bucket(struct namecache *ncp, struct componentname *cnp,
1047 uint32_t hash, struct rwlock *blp)
1049 struct mtx *dvlp, *vlp;
1052 cache_assert_bucket_locked(ncp, RA_WLOCKED);
1054 dvlp = VP2VNODELOCK(ncp->nc_dvp);
1056 if (!(ncp->nc_flag & NCF_NEGATIVE))
1057 vlp = VP2VNODELOCK(ncp->nc_vp);
1058 if (cache_trylock_vnodes(dvlp, vlp) == 0) {
1059 cache_zap_locked(ncp, false);
1061 cache_unlock_vnodes(dvlp, vlp);
1067 return (cache_zap_unlocked_bucket(ncp, cnp, dvp, dvlp, vlp, hash, blp));
1070 static int __noinline
1071 cache_zap_rlocked_bucket(struct namecache *ncp, struct componentname *cnp,
1072 uint32_t hash, struct rwlock *blp)
1074 struct mtx *dvlp, *vlp;
1077 cache_assert_bucket_locked(ncp, RA_RLOCKED);
1079 dvlp = VP2VNODELOCK(ncp->nc_dvp);
1081 if (!(ncp->nc_flag & NCF_NEGATIVE))
1082 vlp = VP2VNODELOCK(ncp->nc_vp);
1083 if (cache_trylock_vnodes(dvlp, vlp) == 0) {
1086 cache_zap_locked(ncp, false);
1088 cache_unlock_vnodes(dvlp, vlp);
1094 return (cache_zap_unlocked_bucket(ncp, cnp, dvp, dvlp, vlp, hash, blp));
1098 cache_zap_wlocked_bucket_kl(struct namecache *ncp, struct rwlock *blp,
1099 struct mtx **vlpp1, struct mtx **vlpp2)
1101 struct mtx *dvlp, *vlp;
1103 cache_assert_bucket_locked(ncp, RA_WLOCKED);
1105 dvlp = VP2VNODELOCK(ncp->nc_dvp);
1107 if (!(ncp->nc_flag & NCF_NEGATIVE))
1108 vlp = VP2VNODELOCK(ncp->nc_vp);
1109 cache_sort_vnodes(&dvlp, &vlp);
1111 if (*vlpp1 == dvlp && *vlpp2 == vlp) {
1112 cache_zap_locked(ncp, false);
1113 cache_unlock_vnodes(dvlp, vlp);
1126 if (cache_trylock_vnodes(dvlp, vlp) == 0) {
1127 cache_zap_locked(ncp, false);
1128 cache_unlock_vnodes(dvlp, vlp);
1143 cache_lookup_unlock(struct rwlock *blp, struct mtx *vlp)
1153 static int __noinline
1154 cache_lookup_dot(struct vnode *dvp, struct vnode **vpp, struct componentname *cnp,
1155 struct timespec *tsp, int *ticksp)
1160 CTR2(KTR_VFS, "cache_lookup(%p, %s) found via .",
1161 dvp, cnp->cn_nameptr);
1162 counter_u64_add(dothits, 1);
1163 SDT_PROBE3(vfs, namecache, lookup, hit, dvp, ".", *vpp);
1170 * When we lookup "." we still can be asked to lock it
1173 ltype = cnp->cn_lkflags & LK_TYPE_MASK;
1174 if (ltype != VOP_ISLOCKED(*vpp)) {
1175 if (ltype == LK_EXCLUSIVE) {
1176 vn_lock(*vpp, LK_UPGRADE | LK_RETRY);
1177 if ((*vpp)->v_iflag & VI_DOOMED) {
1178 /* forced unmount */
1184 vn_lock(*vpp, LK_DOWNGRADE | LK_RETRY);
1189 static __noinline int
1190 cache_lookup_nomakeentry(struct vnode *dvp, struct vnode **vpp,
1191 struct componentname *cnp, struct timespec *tsp, int *ticksp)
1193 struct namecache *ncp;
1195 struct mtx *dvlp, *dvlp2;
1199 if (cnp->cn_namelen == 2 &&
1200 cnp->cn_nameptr[0] == '.' && cnp->cn_nameptr[1] == '.') {
1201 counter_u64_add(dotdothits, 1);
1202 dvlp = VP2VNODELOCK(dvp);
1206 ncp = dvp->v_cache_dd;
1208 SDT_PROBE3(vfs, namecache, lookup, miss, dvp,
1215 if ((ncp->nc_flag & NCF_ISDOTDOT) != 0) {
1216 if (ncp->nc_dvp != dvp)
1217 panic("dvp %p v_cache_dd %p\n", dvp, ncp);
1218 if (!cache_zap_locked_vnode_kl2(ncp,
1221 MPASS(dvp->v_cache_dd == NULL);
1227 dvp->v_cache_dd = NULL;
1235 hash = cache_get_hash(cnp->cn_nameptr, cnp->cn_namelen, dvp);
1236 blp = HASH2BUCKETLOCK(hash);
1238 if (LIST_EMPTY(NCHHASH(hash)))
1243 LIST_FOREACH(ncp, (NCHHASH(hash)), nc_hash) {
1244 counter_u64_add(numchecks, 1);
1245 if (ncp->nc_dvp == dvp && ncp->nc_nlen == cnp->cn_namelen &&
1246 !bcmp(ncp->nc_name, cnp->cn_nameptr, ncp->nc_nlen))
1250 /* We failed to find an entry */
1256 error = cache_zap_wlocked_bucket(ncp, cnp, hash, blp);
1257 if (__predict_false(error != 0)) {
1258 zap_and_exit_bucket_fail++;
1259 cache_maybe_yield();
1262 counter_u64_add(numposzaps, 1);
1266 SDT_PROBE3(vfs, namecache, lookup, miss, dvp, cnp->cn_nameptr, NULL);
1267 counter_u64_add(nummisszap, 1);
1272 * Lookup a name in the name cache
1276 * - dvp: Parent directory in which to search.
1277 * - vpp: Return argument. Will contain desired vnode on cache hit.
1278 * - cnp: Parameters of the name search. The most interesting bits of
1279 * the cn_flags field have the following meanings:
1280 * - MAKEENTRY: If clear, free an entry from the cache rather than look
1282 * - ISDOTDOT: Must be set if and only if cn_nameptr == ".."
1283 * - tsp: Return storage for cache timestamp. On a successful (positive
1284 * or negative) lookup, tsp will be filled with any timespec that
1285 * was stored when this cache entry was created. However, it will
1286 * be clear for "." entries.
1287 * - ticks: Return storage for alternate cache timestamp. On a successful
1288 * (positive or negative) lookup, it will contain the ticks value
1289 * that was current when the cache entry was created, unless cnp
1294 * - -1: A positive cache hit. vpp will contain the desired vnode.
1295 * - ENOENT: A negative cache hit, or dvp was recycled out from under us due
1296 * to a forced unmount. vpp will not be modified. If the entry
1297 * is a whiteout, then the ISWHITEOUT flag will be set in
1299 * - 0: A cache miss. vpp will not be modified.
1303 * On a cache hit, vpp will be returned locked and ref'd. If we're looking up
1304 * .., dvp is unlocked. If we're looking up . an extra ref is taken, but the
1305 * lock is not recursively acquired.
1308 cache_lookup(struct vnode *dvp, struct vnode **vpp, struct componentname *cnp,
1309 struct timespec *tsp, int *ticksp)
1311 struct namecache_ts *ncp_ts;
1312 struct namecache *ncp;
1319 if (__predict_false(!doingcache)) {
1320 cnp->cn_flags &= ~MAKEENTRY;
1324 counter_u64_add(numcalls, 1);
1326 if (__predict_false(cnp->cn_namelen == 1 && cnp->cn_nameptr[0] == '.'))
1327 return (cache_lookup_dot(dvp, vpp, cnp, tsp, ticksp));
1329 if ((cnp->cn_flags & MAKEENTRY) == 0)
1330 return (cache_lookup_nomakeentry(dvp, vpp, cnp, tsp, ticksp));
1336 if (cnp->cn_namelen == 2 &&
1337 cnp->cn_nameptr[0] == '.' && cnp->cn_nameptr[1] == '.') {
1338 counter_u64_add(dotdothits, 1);
1339 dvlp = VP2VNODELOCK(dvp);
1341 ncp = dvp->v_cache_dd;
1343 SDT_PROBE3(vfs, namecache, lookup, miss, dvp,
1348 if ((ncp->nc_flag & NCF_ISDOTDOT) != 0) {
1349 if (ncp->nc_flag & NCF_NEGATIVE)
1355 /* Return failure if negative entry was found. */
1357 goto negative_success;
1358 CTR3(KTR_VFS, "cache_lookup(%p, %s) found %p via ..",
1359 dvp, cnp->cn_nameptr, *vpp);
1360 SDT_PROBE3(vfs, namecache, lookup, hit, dvp, "..",
1362 cache_out_ts(ncp, tsp, ticksp);
1363 if ((ncp->nc_flag & (NCF_ISDOTDOT | NCF_DTS)) ==
1364 NCF_DTS && tsp != NULL) {
1365 ncp_ts = __containerof(ncp, struct namecache_ts, nc_nc);
1366 *tsp = ncp_ts->nc_dotdottime;
1371 hash = cache_get_hash(cnp->cn_nameptr, cnp->cn_namelen, dvp);
1372 blp = HASH2BUCKETLOCK(hash);
1375 LIST_FOREACH(ncp, (NCHHASH(hash)), nc_hash) {
1376 counter_u64_add(numchecks, 1);
1377 if (ncp->nc_dvp == dvp && ncp->nc_nlen == cnp->cn_namelen &&
1378 !bcmp(ncp->nc_name, cnp->cn_nameptr, ncp->nc_nlen))
1382 /* We failed to find an entry */
1385 SDT_PROBE3(vfs, namecache, lookup, miss, dvp, cnp->cn_nameptr,
1387 counter_u64_add(nummiss, 1);
1391 /* We found a "positive" match, return the vnode */
1392 if (!(ncp->nc_flag & NCF_NEGATIVE)) {
1393 counter_u64_add(numposhits, 1);
1395 CTR4(KTR_VFS, "cache_lookup(%p, %s) found %p via ncp %p",
1396 dvp, cnp->cn_nameptr, *vpp, ncp);
1397 SDT_PROBE3(vfs, namecache, lookup, hit, dvp, ncp->nc_name,
1399 cache_out_ts(ncp, tsp, ticksp);
1404 /* We found a negative match, and want to create it, so purge */
1405 if (cnp->cn_nameiop == CREATE) {
1406 counter_u64_add(numnegzaps, 1);
1410 counter_u64_add(numneghits, 1);
1411 cache_negative_hit(ncp);
1412 if (ncp->nc_flag & NCF_WHITE)
1413 cnp->cn_flags |= ISWHITEOUT;
1414 SDT_PROBE2(vfs, namecache, lookup, hit__negative, dvp,
1416 cache_out_ts(ncp, tsp, ticksp);
1417 cache_lookup_unlock(blp, dvlp);
1422 * On success we return a locked and ref'd vnode as per the lookup
1426 ltype = 0; /* silence gcc warning */
1427 if (cnp->cn_flags & ISDOTDOT) {
1428 ltype = VOP_ISLOCKED(dvp);
1431 vs = vget_prep(*vpp);
1432 cache_lookup_unlock(blp, dvlp);
1433 error = vget_finish(*vpp, cnp->cn_lkflags, vs);
1434 if (cnp->cn_flags & ISDOTDOT) {
1435 vn_lock(dvp, ltype | LK_RETRY);
1436 if (dvp->v_iflag & VI_DOOMED) {
1447 if ((cnp->cn_flags & ISLASTCN) &&
1448 (cnp->cn_lkflags & LK_TYPE_MASK) == LK_EXCLUSIVE) {
1449 ASSERT_VOP_ELOCKED(*vpp, "cache_lookup");
1455 error = cache_zap_rlocked_bucket(ncp, cnp, hash, blp);
1457 error = cache_zap_locked_vnode(ncp, dvp);
1458 if (__predict_false(error != 0)) {
1459 zap_and_exit_bucket_fail2++;
1460 cache_maybe_yield();
1467 struct celockstate {
1469 struct rwlock *blp[2];
1471 CTASSERT((nitems(((struct celockstate *)0)->vlp) == 3));
1472 CTASSERT((nitems(((struct celockstate *)0)->blp) == 2));
1475 cache_celockstate_init(struct celockstate *cel)
1478 bzero(cel, sizeof(*cel));
1482 cache_lock_vnodes_cel(struct celockstate *cel, struct vnode *vp,
1485 struct mtx *vlp1, *vlp2;
1487 MPASS(cel->vlp[0] == NULL);
1488 MPASS(cel->vlp[1] == NULL);
1489 MPASS(cel->vlp[2] == NULL);
1491 MPASS(vp != NULL || dvp != NULL);
1493 vlp1 = VP2VNODELOCK(vp);
1494 vlp2 = VP2VNODELOCK(dvp);
1495 cache_sort_vnodes(&vlp1, &vlp2);
1506 cache_unlock_vnodes_cel(struct celockstate *cel)
1509 MPASS(cel->vlp[0] != NULL || cel->vlp[1] != NULL);
1511 if (cel->vlp[0] != NULL)
1512 mtx_unlock(cel->vlp[0]);
1513 if (cel->vlp[1] != NULL)
1514 mtx_unlock(cel->vlp[1]);
1515 if (cel->vlp[2] != NULL)
1516 mtx_unlock(cel->vlp[2]);
1520 cache_lock_vnodes_cel_3(struct celockstate *cel, struct vnode *vp)
1525 cache_assert_vlp_locked(cel->vlp[0]);
1526 cache_assert_vlp_locked(cel->vlp[1]);
1527 MPASS(cel->vlp[2] == NULL);
1530 vlp = VP2VNODELOCK(vp);
1533 if (vlp >= cel->vlp[1]) {
1536 if (mtx_trylock(vlp))
1538 cache_lock_vnodes_cel_3_failures++;
1539 cache_unlock_vnodes_cel(cel);
1540 if (vlp < cel->vlp[0]) {
1542 mtx_lock(cel->vlp[0]);
1543 mtx_lock(cel->vlp[1]);
1545 if (cel->vlp[0] != NULL)
1546 mtx_lock(cel->vlp[0]);
1548 mtx_lock(cel->vlp[1]);
1558 cache_lock_buckets_cel(struct celockstate *cel, struct rwlock *blp1,
1559 struct rwlock *blp2)
1562 MPASS(cel->blp[0] == NULL);
1563 MPASS(cel->blp[1] == NULL);
1565 cache_sort_vnodes(&blp1, &blp2);
1576 cache_unlock_buckets_cel(struct celockstate *cel)
1579 if (cel->blp[0] != NULL)
1580 rw_wunlock(cel->blp[0]);
1581 rw_wunlock(cel->blp[1]);
1585 * Lock part of the cache affected by the insertion.
1587 * This means vnodelocks for dvp, vp and the relevant bucketlock.
1588 * However, insertion can result in removal of an old entry. In this
1589 * case we have an additional vnode and bucketlock pair to lock. If the
1590 * entry is negative, ncelock is locked instead of the vnode.
1592 * That is, in the worst case we have to lock 3 vnodes and 2 bucketlocks, while
1593 * preserving the locking order (smaller address first).
1596 cache_enter_lock(struct celockstate *cel, struct vnode *dvp, struct vnode *vp,
1599 struct namecache *ncp;
1600 struct rwlock *blps[2];
1602 blps[0] = HASH2BUCKETLOCK(hash);
1605 cache_lock_vnodes_cel(cel, dvp, vp);
1606 if (vp == NULL || vp->v_type != VDIR)
1608 ncp = vp->v_cache_dd;
1611 if ((ncp->nc_flag & NCF_ISDOTDOT) == 0)
1613 MPASS(ncp->nc_dvp == vp);
1614 blps[1] = NCP2BUCKETLOCK(ncp);
1615 if (ncp->nc_flag & NCF_NEGATIVE)
1617 if (cache_lock_vnodes_cel_3(cel, ncp->nc_vp))
1620 * All vnodes got re-locked. Re-validate the state and if
1621 * nothing changed we are done. Otherwise restart.
1623 if (ncp == vp->v_cache_dd &&
1624 (ncp->nc_flag & NCF_ISDOTDOT) != 0 &&
1625 blps[1] == NCP2BUCKETLOCK(ncp) &&
1626 VP2VNODELOCK(ncp->nc_vp) == cel->vlp[2])
1628 cache_unlock_vnodes_cel(cel);
1633 cache_lock_buckets_cel(cel, blps[0], blps[1]);
1637 cache_enter_lock_dd(struct celockstate *cel, struct vnode *dvp, struct vnode *vp,
1640 struct namecache *ncp;
1641 struct rwlock *blps[2];
1643 blps[0] = HASH2BUCKETLOCK(hash);
1646 cache_lock_vnodes_cel(cel, dvp, vp);
1647 ncp = dvp->v_cache_dd;
1650 if ((ncp->nc_flag & NCF_ISDOTDOT) == 0)
1652 MPASS(ncp->nc_dvp == dvp);
1653 blps[1] = NCP2BUCKETLOCK(ncp);
1654 if (ncp->nc_flag & NCF_NEGATIVE)
1656 if (cache_lock_vnodes_cel_3(cel, ncp->nc_vp))
1658 if (ncp == dvp->v_cache_dd &&
1659 (ncp->nc_flag & NCF_ISDOTDOT) != 0 &&
1660 blps[1] == NCP2BUCKETLOCK(ncp) &&
1661 VP2VNODELOCK(ncp->nc_vp) == cel->vlp[2])
1663 cache_unlock_vnodes_cel(cel);
1668 cache_lock_buckets_cel(cel, blps[0], blps[1]);
1672 cache_enter_unlock(struct celockstate *cel)
1675 cache_unlock_buckets_cel(cel);
1676 cache_unlock_vnodes_cel(cel);
1680 * Add an entry to the cache.
1683 cache_enter_time(struct vnode *dvp, struct vnode *vp, struct componentname *cnp,
1684 struct timespec *tsp, struct timespec *dtsp)
1686 struct celockstate cel;
1687 struct namecache *ncp, *n2, *ndd;
1688 struct namecache_ts *ncp_ts, *n2_ts;
1689 struct nchashhead *ncpp;
1690 struct neglist *neglist;
1697 CTR3(KTR_VFS, "cache_enter(%p, %p, %s)", dvp, vp, cnp->cn_nameptr);
1698 VNASSERT(vp == NULL || (vp->v_iflag & VI_DOOMED) == 0, vp,
1699 ("cache_enter: Adding a doomed vnode"));
1700 VNASSERT(dvp == NULL || (dvp->v_iflag & VI_DOOMED) == 0, dvp,
1701 ("cache_enter: Doomed vnode used as src"));
1703 if (__predict_false(!doingcache))
1707 * Avoid blowout in namecache entries.
1709 lnumcache = atomic_fetchadd_long(&numcache, 1) + 1;
1710 if (__predict_false(lnumcache >= desiredvnodes * ncsizefactor)) {
1711 atomic_add_long(&numcache, -1);
1715 cache_celockstate_init(&cel);
1719 if (cnp->cn_nameptr[0] == '.') {
1720 if (cnp->cn_namelen == 1)
1722 if (cnp->cn_namelen == 2 && cnp->cn_nameptr[1] == '.') {
1723 len = cnp->cn_namelen;
1724 hash = cache_get_hash(cnp->cn_nameptr, len, dvp);
1725 cache_enter_lock_dd(&cel, dvp, vp, hash);
1727 * If dotdot entry already exists, just retarget it
1728 * to new parent vnode, otherwise continue with new
1729 * namecache entry allocation.
1731 if ((ncp = dvp->v_cache_dd) != NULL &&
1732 ncp->nc_flag & NCF_ISDOTDOT) {
1733 KASSERT(ncp->nc_dvp == dvp,
1734 ("wrong isdotdot parent"));
1736 if (ncp->nc_flag & NCF_NEGATIVE || vp == NULL) {
1737 neglist = NCP2NEGLIST(ncp);
1738 mtx_lock(&ncneg_hot.nl_lock);
1739 mtx_lock(&neglist->nl_lock);
1742 if (!(ncp->nc_flag & NCF_NEGATIVE)) {
1743 TAILQ_REMOVE(&ncp->nc_vp->v_cache_dst,
1746 cache_negative_remove(ncp, true);
1749 TAILQ_INSERT_HEAD(&vp->v_cache_dst,
1751 ncp->nc_flag &= ~(NCF_NEGATIVE|NCF_HOTNEGATIVE);
1753 ncp->nc_flag &= ~(NCF_HOTNEGATIVE);
1754 ncp->nc_flag |= NCF_NEGATIVE;
1755 cache_negative_insert(ncp, true);
1758 mtx_unlock(&neglist->nl_lock);
1759 mtx_unlock(&ncneg_hot.nl_lock);
1762 cache_enter_unlock(&cel);
1765 dvp->v_cache_dd = NULL;
1766 cache_enter_unlock(&cel);
1767 cache_celockstate_init(&cel);
1768 SDT_PROBE3(vfs, namecache, enter, done, dvp, "..", vp);
1769 flag = NCF_ISDOTDOT;
1774 * Calculate the hash key and setup as much of the new
1775 * namecache entry as possible before acquiring the lock.
1777 ncp = cache_alloc(cnp->cn_namelen, tsp != NULL);
1778 ncp->nc_flag = flag;
1781 ncp->nc_flag |= NCF_NEGATIVE;
1784 ncp_ts = __containerof(ncp, struct namecache_ts, nc_nc);
1785 ncp_ts->nc_time = *tsp;
1786 ncp_ts->nc_ticks = ticks;
1787 ncp_ts->nc_nc.nc_flag |= NCF_TS;
1789 ncp_ts->nc_dotdottime = *dtsp;
1790 ncp_ts->nc_nc.nc_flag |= NCF_DTS;
1793 len = ncp->nc_nlen = cnp->cn_namelen;
1794 hash = cache_get_hash(cnp->cn_nameptr, len, dvp);
1795 strlcpy(ncp->nc_name, cnp->cn_nameptr, len + 1);
1796 cache_enter_lock(&cel, dvp, vp, hash);
1799 * See if this vnode or negative entry is already in the cache
1800 * with this name. This can happen with concurrent lookups of
1801 * the same path name.
1803 ncpp = NCHHASH(hash);
1804 LIST_FOREACH(n2, ncpp, nc_hash) {
1805 if (n2->nc_dvp == dvp &&
1806 n2->nc_nlen == cnp->cn_namelen &&
1807 !bcmp(n2->nc_name, cnp->cn_nameptr, n2->nc_nlen)) {
1809 KASSERT((n2->nc_flag & NCF_TS) != 0,
1811 n2_ts = __containerof(n2, struct namecache_ts, nc_nc);
1812 n2_ts->nc_time = ncp_ts->nc_time;
1813 n2_ts->nc_ticks = ncp_ts->nc_ticks;
1815 n2_ts->nc_dotdottime = ncp_ts->nc_dotdottime;
1816 if (ncp->nc_flag & NCF_NEGATIVE)
1817 mtx_lock(&ncneg_hot.nl_lock);
1818 n2_ts->nc_nc.nc_flag |= NCF_DTS;
1819 if (ncp->nc_flag & NCF_NEGATIVE)
1820 mtx_unlock(&ncneg_hot.nl_lock);
1823 goto out_unlock_free;
1827 if (flag == NCF_ISDOTDOT) {
1829 * See if we are trying to add .. entry, but some other lookup
1830 * has populated v_cache_dd pointer already.
1832 if (dvp->v_cache_dd != NULL)
1833 goto out_unlock_free;
1834 KASSERT(vp == NULL || vp->v_type == VDIR,
1835 ("wrong vnode type %p", vp));
1836 dvp->v_cache_dd = ncp;
1840 if (vp->v_type == VDIR) {
1841 if (flag != NCF_ISDOTDOT) {
1843 * For this case, the cache entry maps both the
1844 * directory name in it and the name ".." for the
1845 * directory's parent.
1847 if ((ndd = vp->v_cache_dd) != NULL) {
1848 if ((ndd->nc_flag & NCF_ISDOTDOT) != 0)
1849 cache_zap_locked(ndd, false);
1853 vp->v_cache_dd = ncp;
1856 vp->v_cache_dd = NULL;
1860 if (flag != NCF_ISDOTDOT) {
1861 if (LIST_EMPTY(&dvp->v_cache_src)) {
1863 atomic_add_rel_long(&numcachehv, 1);
1865 LIST_INSERT_HEAD(&dvp->v_cache_src, ncp, nc_src);
1869 * Insert the new namecache entry into the appropriate chain
1870 * within the cache entries table.
1872 LIST_INSERT_HEAD(ncpp, ncp, nc_hash);
1875 * If the entry is "negative", we place it into the
1876 * "negative" cache queue, otherwise, we place it into the
1877 * destination vnode's cache entries queue.
1880 TAILQ_INSERT_HEAD(&vp->v_cache_dst, ncp, nc_dst);
1881 SDT_PROBE3(vfs, namecache, enter, done, dvp, ncp->nc_name,
1884 if (cnp->cn_flags & ISWHITEOUT)
1885 ncp->nc_flag |= NCF_WHITE;
1886 cache_negative_insert(ncp, false);
1887 SDT_PROBE2(vfs, namecache, enter_negative, done, dvp,
1890 cache_enter_unlock(&cel);
1891 if (numneg * ncnegfactor > lnumcache)
1892 cache_negative_zap_one();
1896 cache_enter_unlock(&cel);
1902 cache_roundup_2(u_int val)
1906 for (res = 1; res <= val; res <<= 1)
1913 * Name cache initialization, from vfs_init() when we are booting
1916 nchinit(void *dummy __unused)
1920 cache_zone_small = uma_zcreate("S VFS Cache",
1921 sizeof(struct namecache) + CACHE_PATH_CUTOFF + 1,
1922 NULL, NULL, NULL, NULL, UMA_ALIGNOF(struct namecache),
1924 cache_zone_small_ts = uma_zcreate("STS VFS Cache",
1925 sizeof(struct namecache_ts) + CACHE_PATH_CUTOFF + 1,
1926 NULL, NULL, NULL, NULL, UMA_ALIGNOF(struct namecache_ts),
1928 cache_zone_large = uma_zcreate("L VFS Cache",
1929 sizeof(struct namecache) + NAME_MAX + 1,
1930 NULL, NULL, NULL, NULL, UMA_ALIGNOF(struct namecache),
1932 cache_zone_large_ts = uma_zcreate("LTS VFS Cache",
1933 sizeof(struct namecache_ts) + NAME_MAX + 1,
1934 NULL, NULL, NULL, NULL, UMA_ALIGNOF(struct namecache_ts),
1937 nchashtbl = hashinit(desiredvnodes * 2, M_VFSCACHE, &nchash);
1938 ncbuckethash = cache_roundup_2(mp_ncpus * mp_ncpus) - 1;
1939 if (ncbuckethash < 7) /* arbitrarily chosen to avoid having one lock */
1941 if (ncbuckethash > nchash)
1942 ncbuckethash = nchash;
1943 bucketlocks = malloc(sizeof(*bucketlocks) * numbucketlocks, M_VFSCACHE,
1945 for (i = 0; i < numbucketlocks; i++)
1946 rw_init_flags(&bucketlocks[i], "ncbuc", RW_DUPOK | RW_RECURSE);
1947 ncvnodehash = ncbuckethash;
1948 vnodelocks = malloc(sizeof(*vnodelocks) * numvnodelocks, M_VFSCACHE,
1950 for (i = 0; i < numvnodelocks; i++)
1951 mtx_init(&vnodelocks[i], "ncvn", NULL, MTX_DUPOK | MTX_RECURSE);
1952 ncpurgeminvnodes = numbucketlocks * 2;
1955 neglists = malloc(sizeof(*neglists) * numneglists, M_VFSCACHE,
1957 for (i = 0; i < numneglists; i++) {
1958 mtx_init(&neglists[i].nl_lock, "ncnegl", NULL, MTX_DEF);
1959 TAILQ_INIT(&neglists[i].nl_list);
1961 mtx_init(&ncneg_hot.nl_lock, "ncneglh", NULL, MTX_DEF);
1962 TAILQ_INIT(&ncneg_hot.nl_list);
1964 mtx_init(&ncneg_shrink_lock, "ncnegs", NULL, MTX_DEF);
1966 numcalls = counter_u64_alloc(M_WAITOK);
1967 dothits = counter_u64_alloc(M_WAITOK);
1968 dotdothits = counter_u64_alloc(M_WAITOK);
1969 numchecks = counter_u64_alloc(M_WAITOK);
1970 nummiss = counter_u64_alloc(M_WAITOK);
1971 nummisszap = counter_u64_alloc(M_WAITOK);
1972 numposzaps = counter_u64_alloc(M_WAITOK);
1973 numposhits = counter_u64_alloc(M_WAITOK);
1974 numnegzaps = counter_u64_alloc(M_WAITOK);
1975 numneghits = counter_u64_alloc(M_WAITOK);
1976 numfullpathcalls = counter_u64_alloc(M_WAITOK);
1977 numfullpathfail1 = counter_u64_alloc(M_WAITOK);
1978 numfullpathfail2 = counter_u64_alloc(M_WAITOK);
1979 numfullpathfail4 = counter_u64_alloc(M_WAITOK);
1980 numfullpathfound = counter_u64_alloc(M_WAITOK);
1981 zap_and_exit_bucket_relock_success = counter_u64_alloc(M_WAITOK);
1983 SYSINIT(vfs, SI_SUB_VFS, SI_ORDER_SECOND, nchinit, NULL);
1986 cache_changesize(int newmaxvnodes)
1988 struct nchashhead *new_nchashtbl, *old_nchashtbl;
1989 u_long new_nchash, old_nchash;
1990 struct namecache *ncp;
1994 newmaxvnodes = cache_roundup_2(newmaxvnodes * 2);
1995 if (newmaxvnodes < numbucketlocks)
1996 newmaxvnodes = numbucketlocks;
1998 new_nchashtbl = hashinit(newmaxvnodes, M_VFSCACHE, &new_nchash);
1999 /* If same hash table size, nothing to do */
2000 if (nchash == new_nchash) {
2001 free(new_nchashtbl, M_VFSCACHE);
2005 * Move everything from the old hash table to the new table.
2006 * None of the namecache entries in the table can be removed
2007 * because to do so, they have to be removed from the hash table.
2009 cache_lock_all_vnodes();
2010 cache_lock_all_buckets();
2011 old_nchashtbl = nchashtbl;
2012 old_nchash = nchash;
2013 nchashtbl = new_nchashtbl;
2014 nchash = new_nchash;
2015 for (i = 0; i <= old_nchash; i++) {
2016 while ((ncp = LIST_FIRST(&old_nchashtbl[i])) != NULL) {
2017 hash = cache_get_hash(ncp->nc_name, ncp->nc_nlen,
2019 LIST_REMOVE(ncp, nc_hash);
2020 LIST_INSERT_HEAD(NCHHASH(hash), ncp, nc_hash);
2023 cache_unlock_all_buckets();
2024 cache_unlock_all_vnodes();
2025 free(old_nchashtbl, M_VFSCACHE);
2029 * Invalidate all entries from and to a particular vnode.
2032 cache_purge(struct vnode *vp)
2034 TAILQ_HEAD(, namecache) ncps;
2035 struct namecache *ncp, *nnp;
2036 struct mtx *vlp, *vlp2;
2038 CTR1(KTR_VFS, "cache_purge(%p)", vp);
2039 SDT_PROBE1(vfs, namecache, purge, done, vp);
2040 if (LIST_EMPTY(&vp->v_cache_src) && TAILQ_EMPTY(&vp->v_cache_dst) &&
2041 vp->v_cache_dd == NULL)
2044 vlp = VP2VNODELOCK(vp);
2048 while (!LIST_EMPTY(&vp->v_cache_src)) {
2049 ncp = LIST_FIRST(&vp->v_cache_src);
2050 if (!cache_zap_locked_vnode_kl2(ncp, vp, &vlp2))
2052 TAILQ_INSERT_TAIL(&ncps, ncp, nc_dst);
2054 while (!TAILQ_EMPTY(&vp->v_cache_dst)) {
2055 ncp = TAILQ_FIRST(&vp->v_cache_dst);
2056 if (!cache_zap_locked_vnode_kl2(ncp, vp, &vlp2))
2058 TAILQ_INSERT_TAIL(&ncps, ncp, nc_dst);
2060 ncp = vp->v_cache_dd;
2062 KASSERT(ncp->nc_flag & NCF_ISDOTDOT,
2063 ("lost dotdot link"));
2064 if (!cache_zap_locked_vnode_kl2(ncp, vp, &vlp2))
2066 TAILQ_INSERT_TAIL(&ncps, ncp, nc_dst);
2068 KASSERT(vp->v_cache_dd == NULL, ("incomplete purge"));
2072 TAILQ_FOREACH_SAFE(ncp, &ncps, nc_dst, nnp) {
2078 * Invalidate all negative entries for a particular directory vnode.
2081 cache_purge_negative(struct vnode *vp)
2083 TAILQ_HEAD(, namecache) ncps;
2084 struct namecache *ncp, *nnp;
2087 CTR1(KTR_VFS, "cache_purge_negative(%p)", vp);
2088 SDT_PROBE1(vfs, namecache, purge_negative, done, vp);
2089 if (LIST_EMPTY(&vp->v_cache_src))
2092 vlp = VP2VNODELOCK(vp);
2094 LIST_FOREACH_SAFE(ncp, &vp->v_cache_src, nc_src, nnp) {
2095 if (!(ncp->nc_flag & NCF_NEGATIVE))
2097 cache_zap_negative_locked_vnode_kl(ncp, vp);
2098 TAILQ_INSERT_TAIL(&ncps, ncp, nc_dst);
2101 TAILQ_FOREACH_SAFE(ncp, &ncps, nc_dst, nnp) {
2107 * Flush all entries referencing a particular filesystem.
2110 cache_purgevfs(struct mount *mp, bool force)
2112 TAILQ_HEAD(, namecache) ncps;
2113 struct mtx *vlp1, *vlp2;
2115 struct nchashhead *bucket;
2116 struct namecache *ncp, *nnp;
2117 u_long i, j, n_nchash;
2120 /* Scan hash tables for applicable entries */
2121 SDT_PROBE1(vfs, namecache, purgevfs, done, mp);
2122 if (!force && mp->mnt_nvnodelistsize <= ncpurgeminvnodes)
2125 n_nchash = nchash + 1;
2127 for (i = 0; i < numbucketlocks; i++) {
2128 blp = (struct rwlock *)&bucketlocks[i];
2130 for (j = i; j < n_nchash; j += numbucketlocks) {
2132 bucket = &nchashtbl[j];
2133 LIST_FOREACH_SAFE(ncp, bucket, nc_hash, nnp) {
2134 cache_assert_bucket_locked(ncp, RA_WLOCKED);
2135 if (ncp->nc_dvp->v_mount != mp)
2137 error = cache_zap_wlocked_bucket_kl(ncp, blp,
2141 TAILQ_INSERT_HEAD(&ncps, ncp, nc_dst);
2145 if (vlp1 == NULL && vlp2 == NULL)
2146 cache_maybe_yield();
2153 TAILQ_FOREACH_SAFE(ncp, &ncps, nc_dst, nnp) {
2159 * Perform canonical checks and cache lookup and pass on to filesystem
2160 * through the vop_cachedlookup only if needed.
2164 vfs_cache_lookup(struct vop_lookup_args *ap)
2168 struct vnode **vpp = ap->a_vpp;
2169 struct componentname *cnp = ap->a_cnp;
2170 struct ucred *cred = cnp->cn_cred;
2171 int flags = cnp->cn_flags;
2172 struct thread *td = cnp->cn_thread;
2177 if (dvp->v_type != VDIR)
2180 if ((flags & ISLASTCN) && (dvp->v_mount->mnt_flag & MNT_RDONLY) &&
2181 (cnp->cn_nameiop == DELETE || cnp->cn_nameiop == RENAME))
2184 error = VOP_ACCESS(dvp, VEXEC, cred, td);
2188 error = cache_lookup(dvp, vpp, cnp, NULL, NULL);
2190 return (VOP_CACHEDLOOKUP(dvp, vpp, cnp));
2197 * XXX All of these sysctls would probably be more productive dead.
2199 static int __read_mostly disablecwd;
2200 SYSCTL_INT(_debug, OID_AUTO, disablecwd, CTLFLAG_RW, &disablecwd, 0,
2201 "Disable the getcwd syscall");
2203 /* Implementation of the getcwd syscall. */
2205 sys___getcwd(struct thread *td, struct __getcwd_args *uap)
2208 return (kern___getcwd(td, uap->buf, UIO_USERSPACE, uap->buflen,
2213 kern___getcwd(struct thread *td, char *buf, enum uio_seg bufseg, size_t buflen,
2217 struct filedesc *fdp;
2218 struct vnode *cdir, *rdir;
2221 if (__predict_false(disablecwd))
2223 if (__predict_false(buflen < 2))
2225 if (buflen > path_max)
2228 tmpbuf = malloc(buflen, M_TEMP, M_WAITOK);
2229 fdp = td->td_proc->p_fd;
2230 FILEDESC_SLOCK(fdp);
2231 cdir = fdp->fd_cdir;
2233 rdir = fdp->fd_rdir;
2235 FILEDESC_SUNLOCK(fdp);
2236 error = vn_fullpath1(td, cdir, rdir, tmpbuf, &bp, buflen);
2241 if (bufseg == UIO_SYSSPACE)
2242 bcopy(bp, buf, strlen(bp) + 1);
2244 error = copyout(bp, buf, strlen(bp) + 1);
2246 if (KTRPOINT(curthread, KTR_NAMEI))
2250 free(tmpbuf, M_TEMP);
2255 * Thus begins the fullpath magic.
2258 static int __read_mostly disablefullpath;
2259 SYSCTL_INT(_debug, OID_AUTO, disablefullpath, CTLFLAG_RW, &disablefullpath, 0,
2260 "Disable the vn_fullpath function");
2263 * Retrieve the full filesystem path that correspond to a vnode from the name
2264 * cache (if available)
2267 vn_fullpath(struct thread *td, struct vnode *vn, char **retbuf, char **freebuf)
2270 struct filedesc *fdp;
2274 if (__predict_false(disablefullpath))
2276 if (__predict_false(vn == NULL))
2279 buf = malloc(MAXPATHLEN, M_TEMP, M_WAITOK);
2280 fdp = td->td_proc->p_fd;
2281 FILEDESC_SLOCK(fdp);
2282 rdir = fdp->fd_rdir;
2284 FILEDESC_SUNLOCK(fdp);
2285 error = vn_fullpath1(td, vn, rdir, buf, retbuf, MAXPATHLEN);
2296 * This function is similar to vn_fullpath, but it attempts to lookup the
2297 * pathname relative to the global root mount point. This is required for the
2298 * auditing sub-system, as audited pathnames must be absolute, relative to the
2299 * global root mount point.
2302 vn_fullpath_global(struct thread *td, struct vnode *vn,
2303 char **retbuf, char **freebuf)
2308 if (__predict_false(disablefullpath))
2310 if (__predict_false(vn == NULL))
2312 buf = malloc(MAXPATHLEN, M_TEMP, M_WAITOK);
2313 error = vn_fullpath1(td, vn, rootvnode, buf, retbuf, MAXPATHLEN);
2322 vn_vptocnp(struct vnode **vp, struct ucred *cred, char *buf, u_int *buflen)
2325 struct namecache *ncp;
2329 vlp = VP2VNODELOCK(*vp);
2331 TAILQ_FOREACH(ncp, &((*vp)->v_cache_dst), nc_dst) {
2332 if ((ncp->nc_flag & NCF_ISDOTDOT) == 0)
2336 if (*buflen < ncp->nc_nlen) {
2339 counter_u64_add(numfullpathfail4, 1);
2341 SDT_PROBE3(vfs, namecache, fullpath, return, error,
2345 *buflen -= ncp->nc_nlen;
2346 memcpy(buf + *buflen, ncp->nc_name, ncp->nc_nlen);
2347 SDT_PROBE3(vfs, namecache, fullpath, hit, ncp->nc_dvp,
2356 SDT_PROBE1(vfs, namecache, fullpath, miss, vp);
2359 vn_lock(*vp, LK_SHARED | LK_RETRY);
2360 error = VOP_VPTOCNP(*vp, &dvp, cred, buf, buflen);
2363 counter_u64_add(numfullpathfail2, 1);
2364 SDT_PROBE3(vfs, namecache, fullpath, return, error, vp, NULL);
2369 if (dvp->v_iflag & VI_DOOMED) {
2370 /* forced unmount */
2373 SDT_PROBE3(vfs, namecache, fullpath, return, error, vp, NULL);
2377 * *vp has its use count incremented still.
2384 * The magic behind kern___getcwd() and vn_fullpath().
2387 vn_fullpath1(struct thread *td, struct vnode *vp, struct vnode *rdir,
2388 char *buf, char **retbuf, u_int buflen)
2390 int error, slash_prefixed;
2391 #ifdef KDTRACE_HOOKS
2392 struct vnode *startvp = vp;
2401 SDT_PROBE1(vfs, namecache, fullpath, entry, vp);
2402 counter_u64_add(numfullpathcalls, 1);
2404 if (vp->v_type != VDIR) {
2405 error = vn_vptocnp(&vp, td->td_ucred, buf, &buflen);
2412 buf[--buflen] = '/';
2415 while (vp != rdir && vp != rootvnode) {
2417 * The vp vnode must be already fully constructed,
2418 * since it is either found in namecache or obtained
2419 * from VOP_VPTOCNP(). We may test for VV_ROOT safely
2420 * without obtaining the vnode lock.
2422 if ((vp->v_vflag & VV_ROOT) != 0) {
2423 vn_lock(vp, LK_RETRY | LK_SHARED);
2426 * With the vnode locked, check for races with
2427 * unmount, forced or not. Note that we
2428 * already verified that vp is not equal to
2429 * the root vnode, which means that
2430 * mnt_vnodecovered can be NULL only for the
2433 if ((vp->v_iflag & VI_DOOMED) != 0 ||
2434 (vp1 = vp->v_mount->mnt_vnodecovered) == NULL ||
2435 vp1->v_mountedhere != vp->v_mount) {
2438 SDT_PROBE3(vfs, namecache, fullpath, return,
2448 if (vp->v_type != VDIR) {
2450 counter_u64_add(numfullpathfail1, 1);
2452 SDT_PROBE3(vfs, namecache, fullpath, return,
2456 error = vn_vptocnp(&vp, td->td_ucred, buf, &buflen);
2462 SDT_PROBE3(vfs, namecache, fullpath, return, error,
2466 buf[--buflen] = '/';
2471 if (!slash_prefixed) {
2474 counter_u64_add(numfullpathfail4, 1);
2475 SDT_PROBE3(vfs, namecache, fullpath, return, ENOMEM,
2479 buf[--buflen] = '/';
2481 counter_u64_add(numfullpathfound, 1);
2484 SDT_PROBE3(vfs, namecache, fullpath, return, 0, startvp, buf + buflen);
2485 *retbuf = buf + buflen;
2490 vn_dir_dd_ino(struct vnode *vp)
2492 struct namecache *ncp;
2497 ASSERT_VOP_LOCKED(vp, "vn_dir_dd_ino");
2498 vlp = VP2VNODELOCK(vp);
2500 TAILQ_FOREACH(ncp, &(vp->v_cache_dst), nc_dst) {
2501 if ((ncp->nc_flag & NCF_ISDOTDOT) != 0)
2504 vs = vget_prep(ddvp);
2506 if (vget_finish(ddvp, LK_SHARED | LK_NOWAIT, vs))
2515 vn_commname(struct vnode *vp, char *buf, u_int buflen)
2517 struct namecache *ncp;
2521 vlp = VP2VNODELOCK(vp);
2523 TAILQ_FOREACH(ncp, &vp->v_cache_dst, nc_dst)
2524 if ((ncp->nc_flag & NCF_ISDOTDOT) == 0)
2530 l = min(ncp->nc_nlen, buflen - 1);
2531 memcpy(buf, ncp->nc_name, l);
2538 * This function updates path string to vnode's full global path
2539 * and checks the size of the new path string against the pathlen argument.
2541 * Requires a locked, referenced vnode.
2542 * Vnode is re-locked on success or ENODEV, otherwise unlocked.
2544 * If sysctl debug.disablefullpath is set, ENODEV is returned,
2545 * vnode is left locked and path remain untouched.
2547 * If vp is a directory, the call to vn_fullpath_global() always succeeds
2548 * because it falls back to the ".." lookup if the namecache lookup fails.
2551 vn_path_to_global_path(struct thread *td, struct vnode *vp, char *path,
2554 struct nameidata nd;
2559 ASSERT_VOP_ELOCKED(vp, __func__);
2561 /* Return ENODEV if sysctl debug.disablefullpath==1 */
2562 if (__predict_false(disablefullpath))
2565 /* Construct global filesystem path from vp. */
2567 error = vn_fullpath_global(td, vp, &rpath, &fbuf);
2574 if (strlen(rpath) >= pathlen) {
2576 error = ENAMETOOLONG;
2581 * Re-lookup the vnode by path to detect a possible rename.
2582 * As a side effect, the vnode is relocked.
2583 * If vnode was renamed, return ENOENT.
2585 NDINIT(&nd, LOOKUP, FOLLOW | LOCKLEAF | AUDITVNODE1,
2586 UIO_SYSSPACE, path, td);
2592 NDFREE(&nd, NDF_ONLY_PNBUF);
2596 strcpy(path, rpath);
2609 db_print_vpath(struct vnode *vp)
2612 while (vp != NULL) {
2613 db_printf("%p: ", vp);
2614 if (vp == rootvnode) {
2618 if (vp->v_vflag & VV_ROOT) {
2619 db_printf("<mount point>");
2620 vp = vp->v_mount->mnt_vnodecovered;
2622 struct namecache *ncp;
2626 ncp = TAILQ_FIRST(&vp->v_cache_dst);
2629 for (i = 0; i < ncp->nc_nlen; i++)
2630 db_printf("%c", *ncn++);
2643 DB_SHOW_COMMAND(vpath, db_show_vpath)
2648 db_printf("usage: show vpath <struct vnode *>\n");
2652 vp = (struct vnode *)addr;