in directory vnodes. Allow namecache dotdot entry to be created pointing from child vnode to parent vnode if no existing links in opposite direction exist. Use direct link from parent to child for dotdot lookups otherwise. This restores more efficient dotdot caching in NFS filesystems which was lost when vnodes stoppped being type stable. Reviewed by: kib
1118 lines
28 KiB
C
1118 lines
28 KiB
C
/*-
|
|
* Copyright (c) 1989, 1993, 1995
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* The Regents of the University of California. All rights reserved.
|
|
*
|
|
* This code is derived from software contributed to Berkeley by
|
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* Poul-Henning Kamp of the FreeBSD Project.
|
|
*
|
|
* Redistribution and use in source and binary forms, with or without
|
|
* modification, are permitted provided that the following conditions
|
|
* are met:
|
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* 1. Redistributions of source code must retain the above copyright
|
|
* notice, this list of conditions and the following disclaimer.
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|
* 2. Redistributions in binary form must reproduce the above copyright
|
|
* notice, this list of conditions and the following disclaimer in the
|
|
* documentation and/or other materials provided with the distribution.
|
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* 4. Neither the name of the University nor the names of its contributors
|
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* may be used to endorse or promote products derived from this software
|
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* without specific prior written permission.
|
|
*
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|
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
|
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
|
|
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
|
|
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
|
|
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
|
|
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
|
|
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
|
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
|
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* SUCH DAMAGE.
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*
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* @(#)vfs_cache.c 8.5 (Berkeley) 3/22/95
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|
*/
|
|
|
|
#include <sys/cdefs.h>
|
|
__FBSDID("$FreeBSD$");
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|
|
|
#include "opt_ktrace.h"
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|
|
|
#include <sys/param.h>
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|
#include <sys/filedesc.h>
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|
#include <sys/fnv_hash.h>
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|
#include <sys/kernel.h>
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|
#include <sys/lock.h>
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|
#include <sys/malloc.h>
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|
#include <sys/mount.h>
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|
#include <sys/namei.h>
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|
#include <sys/proc.h>
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|
#include <sys/rwlock.h>
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|
#include <sys/syscallsubr.h>
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|
#include <sys/sysctl.h>
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|
#include <sys/sysproto.h>
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|
#include <sys/systm.h>
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|
#include <sys/vnode.h>
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|
#ifdef KTRACE
|
|
#include <sys/ktrace.h>
|
|
#endif
|
|
|
|
#include <vm/uma.h>
|
|
|
|
/*
|
|
* This structure describes the elements in the cache of recent
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|
* names looked up by namei.
|
|
*/
|
|
|
|
struct namecache {
|
|
LIST_ENTRY(namecache) nc_hash; /* hash chain */
|
|
LIST_ENTRY(namecache) nc_src; /* source vnode list */
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|
TAILQ_ENTRY(namecache) nc_dst; /* destination vnode list */
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|
struct vnode *nc_dvp; /* vnode of parent of name */
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|
struct vnode *nc_vp; /* vnode the name refers to */
|
|
u_char nc_flag; /* flag bits */
|
|
u_char nc_nlen; /* length of name */
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|
char nc_name[0]; /* segment name */
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|
};
|
|
|
|
/*
|
|
* Name caching works as follows:
|
|
*
|
|
* Names found by directory scans are retained in a cache
|
|
* for future reference. It is managed LRU, so frequently
|
|
* used names will hang around. Cache is indexed by hash value
|
|
* obtained from (vp, name) where vp refers to the directory
|
|
* containing name.
|
|
*
|
|
* If it is a "negative" entry, (i.e. for a name that is known NOT to
|
|
* exist) the vnode pointer will be NULL.
|
|
*
|
|
* Upon reaching the last segment of a path, if the reference
|
|
* is for DELETE, or NOCACHE is set (rewrite), and the
|
|
* name is located in the cache, it will be dropped.
|
|
*/
|
|
|
|
/*
|
|
* Structures associated with name cacheing.
|
|
*/
|
|
#define NCHHASH(hash) \
|
|
(&nchashtbl[(hash) & nchash])
|
|
static LIST_HEAD(nchashhead, namecache) *nchashtbl; /* Hash Table */
|
|
static TAILQ_HEAD(, namecache) ncneg; /* Hash Table */
|
|
static u_long nchash; /* size of hash table */
|
|
SYSCTL_ULONG(_debug, OID_AUTO, nchash, CTLFLAG_RD, &nchash, 0, "");
|
|
static u_long ncnegfactor = 16; /* ratio of negative entries */
|
|
SYSCTL_ULONG(_debug, OID_AUTO, ncnegfactor, CTLFLAG_RW, &ncnegfactor, 0, "");
|
|
static u_long numneg; /* number of cache entries allocated */
|
|
SYSCTL_ULONG(_debug, OID_AUTO, numneg, CTLFLAG_RD, &numneg, 0, "");
|
|
static u_long numcache; /* number of cache entries allocated */
|
|
SYSCTL_ULONG(_debug, OID_AUTO, numcache, CTLFLAG_RD, &numcache, 0, "");
|
|
static u_long numcachehv; /* number of cache entries with vnodes held */
|
|
SYSCTL_ULONG(_debug, OID_AUTO, numcachehv, CTLFLAG_RD, &numcachehv, 0, "");
|
|
#if 0
|
|
static u_long numcachepl; /* number of cache purge for leaf entries */
|
|
SYSCTL_ULONG(_debug, OID_AUTO, numcachepl, CTLFLAG_RD, &numcachepl, 0, "");
|
|
#endif
|
|
struct nchstats nchstats; /* cache effectiveness statistics */
|
|
|
|
static struct rwlock cache_lock;
|
|
RW_SYSINIT(vfscache, &cache_lock, "Name Cache");
|
|
|
|
#define CACHE_UPGRADE_LOCK() rw_try_upgrade(&cache_lock)
|
|
#define CACHE_RLOCK() rw_rlock(&cache_lock)
|
|
#define CACHE_RUNLOCK() rw_runlock(&cache_lock)
|
|
#define CACHE_WLOCK() rw_wlock(&cache_lock)
|
|
#define CACHE_WUNLOCK() rw_wunlock(&cache_lock)
|
|
|
|
/*
|
|
* UMA zones for the VFS cache.
|
|
*
|
|
* The small cache is used for entries with short names, which are the
|
|
* most common. The large cache is used for entries which are too big to
|
|
* fit in the small cache.
|
|
*/
|
|
static uma_zone_t cache_zone_small;
|
|
static uma_zone_t cache_zone_large;
|
|
|
|
#define CACHE_PATH_CUTOFF 32
|
|
#define CACHE_ZONE_SMALL (sizeof(struct namecache) + CACHE_PATH_CUTOFF)
|
|
#define CACHE_ZONE_LARGE (sizeof(struct namecache) + NAME_MAX)
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|
|
|
#define cache_alloc(len) uma_zalloc(((len) <= CACHE_PATH_CUTOFF) ? \
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|
cache_zone_small : cache_zone_large, M_WAITOK)
|
|
#define cache_free(ncp) do { \
|
|
if (ncp != NULL) \
|
|
uma_zfree(((ncp)->nc_nlen <= CACHE_PATH_CUTOFF) ? \
|
|
cache_zone_small : cache_zone_large, (ncp)); \
|
|
} while (0)
|
|
|
|
static int doingcache = 1; /* 1 => enable the cache */
|
|
SYSCTL_INT(_debug, OID_AUTO, vfscache, CTLFLAG_RW, &doingcache, 0, "");
|
|
|
|
/* Export size information to userland */
|
|
SYSCTL_INT(_debug_sizeof, OID_AUTO, namecache, CTLFLAG_RD, 0,
|
|
sizeof(struct namecache), "");
|
|
|
|
/*
|
|
* The new name cache statistics
|
|
*/
|
|
static SYSCTL_NODE(_vfs, OID_AUTO, cache, CTLFLAG_RW, 0, "Name cache statistics");
|
|
#define STATNODE(mode, name, var) \
|
|
SYSCTL_ULONG(_vfs_cache, OID_AUTO, name, mode, var, 0, "");
|
|
STATNODE(CTLFLAG_RD, numneg, &numneg);
|
|
STATNODE(CTLFLAG_RD, numcache, &numcache);
|
|
static u_long numcalls; STATNODE(CTLFLAG_RD, numcalls, &numcalls);
|
|
static u_long dothits; STATNODE(CTLFLAG_RD, dothits, &dothits);
|
|
static u_long dotdothits; STATNODE(CTLFLAG_RD, dotdothits, &dotdothits);
|
|
static u_long numchecks; STATNODE(CTLFLAG_RD, numchecks, &numchecks);
|
|
static u_long nummiss; STATNODE(CTLFLAG_RD, nummiss, &nummiss);
|
|
static u_long nummisszap; STATNODE(CTLFLAG_RD, nummisszap, &nummisszap);
|
|
static u_long numposzaps; STATNODE(CTLFLAG_RD, numposzaps, &numposzaps);
|
|
static u_long numposhits; STATNODE(CTLFLAG_RD, numposhits, &numposhits);
|
|
static u_long numnegzaps; STATNODE(CTLFLAG_RD, numnegzaps, &numnegzaps);
|
|
static u_long numneghits; STATNODE(CTLFLAG_RD, numneghits, &numneghits);
|
|
static u_long numupgrades; STATNODE(CTLFLAG_RD, numupgrades, &numupgrades);
|
|
|
|
SYSCTL_OPAQUE(_vfs_cache, OID_AUTO, nchstats, CTLFLAG_RD | CTLFLAG_MPSAFE,
|
|
&nchstats, sizeof(nchstats), "LU", "VFS cache effectiveness statistics");
|
|
|
|
|
|
|
|
static void cache_zap(struct namecache *ncp);
|
|
static int vn_vptocnp(struct vnode **vp, char **bp, char *buf, u_int *buflen);
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static int vn_fullpath1(struct thread *td, struct vnode *vp, struct vnode *rdir,
|
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char *buf, char **retbuf, u_int buflen);
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|
|
|
static MALLOC_DEFINE(M_VFSCACHE, "vfscache", "VFS name cache entries");
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|
|
|
/*
|
|
* Flags in namecache.nc_flag
|
|
*/
|
|
#define NCF_WHITE 0x01
|
|
#define NCF_ISDOTDOT 0x02
|
|
|
|
#ifdef DIAGNOSTIC
|
|
/*
|
|
* Grab an atomic snapshot of the name cache hash chain lengths
|
|
*/
|
|
SYSCTL_NODE(_debug, OID_AUTO, hashstat, CTLFLAG_RW, NULL, "hash table stats");
|
|
|
|
static int
|
|
sysctl_debug_hashstat_rawnchash(SYSCTL_HANDLER_ARGS)
|
|
{
|
|
int error;
|
|
struct nchashhead *ncpp;
|
|
struct namecache *ncp;
|
|
int n_nchash;
|
|
int count;
|
|
|
|
n_nchash = nchash + 1; /* nchash is max index, not count */
|
|
if (!req->oldptr)
|
|
return SYSCTL_OUT(req, 0, n_nchash * sizeof(int));
|
|
|
|
/* Scan hash tables for applicable entries */
|
|
for (ncpp = nchashtbl; n_nchash > 0; n_nchash--, ncpp++) {
|
|
CACHE_RLOCK();
|
|
count = 0;
|
|
LIST_FOREACH(ncp, ncpp, nc_hash) {
|
|
count++;
|
|
}
|
|
CACHE_RUNLOCK();
|
|
error = SYSCTL_OUT(req, &count, sizeof(count));
|
|
if (error)
|
|
return (error);
|
|
}
|
|
return (0);
|
|
}
|
|
SYSCTL_PROC(_debug_hashstat, OID_AUTO, rawnchash, CTLTYPE_INT|CTLFLAG_RD|
|
|
CTLFLAG_MPSAFE, 0, 0, sysctl_debug_hashstat_rawnchash, "S,int",
|
|
"nchash chain lengths");
|
|
|
|
static int
|
|
sysctl_debug_hashstat_nchash(SYSCTL_HANDLER_ARGS)
|
|
{
|
|
int error;
|
|
struct nchashhead *ncpp;
|
|
struct namecache *ncp;
|
|
int n_nchash;
|
|
int count, maxlength, used, pct;
|
|
|
|
if (!req->oldptr)
|
|
return SYSCTL_OUT(req, 0, 4 * sizeof(int));
|
|
|
|
n_nchash = nchash + 1; /* nchash is max index, not count */
|
|
used = 0;
|
|
maxlength = 0;
|
|
|
|
/* Scan hash tables for applicable entries */
|
|
for (ncpp = nchashtbl; n_nchash > 0; n_nchash--, ncpp++) {
|
|
count = 0;
|
|
CACHE_RLOCK();
|
|
LIST_FOREACH(ncp, ncpp, nc_hash) {
|
|
count++;
|
|
}
|
|
CACHE_RUNLOCK();
|
|
if (count)
|
|
used++;
|
|
if (maxlength < count)
|
|
maxlength = count;
|
|
}
|
|
n_nchash = nchash + 1;
|
|
pct = (used * 100 * 100) / n_nchash;
|
|
error = SYSCTL_OUT(req, &n_nchash, sizeof(n_nchash));
|
|
if (error)
|
|
return (error);
|
|
error = SYSCTL_OUT(req, &used, sizeof(used));
|
|
if (error)
|
|
return (error);
|
|
error = SYSCTL_OUT(req, &maxlength, sizeof(maxlength));
|
|
if (error)
|
|
return (error);
|
|
error = SYSCTL_OUT(req, &pct, sizeof(pct));
|
|
if (error)
|
|
return (error);
|
|
return (0);
|
|
}
|
|
SYSCTL_PROC(_debug_hashstat, OID_AUTO, nchash, CTLTYPE_INT|CTLFLAG_RD|
|
|
CTLFLAG_MPSAFE, 0, 0, sysctl_debug_hashstat_nchash, "I",
|
|
"nchash chain lengths");
|
|
#endif
|
|
|
|
/*
|
|
* cache_zap():
|
|
*
|
|
* Removes a namecache entry from cache, whether it contains an actual
|
|
* pointer to a vnode or if it is just a negative cache entry.
|
|
*/
|
|
static void
|
|
cache_zap(ncp)
|
|
struct namecache *ncp;
|
|
{
|
|
struct vnode *vp;
|
|
|
|
rw_assert(&cache_lock, RA_WLOCKED);
|
|
CTR2(KTR_VFS, "cache_zap(%p) vp %p", ncp, ncp->nc_vp);
|
|
vp = NULL;
|
|
LIST_REMOVE(ncp, nc_hash);
|
|
if (ncp->nc_flag & NCF_ISDOTDOT) {
|
|
if (ncp == ncp->nc_dvp->v_cache_dd)
|
|
ncp->nc_dvp->v_cache_dd = NULL;
|
|
} else {
|
|
LIST_REMOVE(ncp, nc_src);
|
|
if (LIST_EMPTY(&ncp->nc_dvp->v_cache_src)) {
|
|
vp = ncp->nc_dvp;
|
|
numcachehv--;
|
|
}
|
|
}
|
|
if (ncp->nc_vp) {
|
|
TAILQ_REMOVE(&ncp->nc_vp->v_cache_dst, ncp, nc_dst);
|
|
if (ncp == ncp->nc_vp->v_cache_dd)
|
|
ncp->nc_vp->v_cache_dd = NULL;
|
|
} else {
|
|
TAILQ_REMOVE(&ncneg, ncp, nc_dst);
|
|
numneg--;
|
|
}
|
|
numcache--;
|
|
cache_free(ncp);
|
|
if (vp)
|
|
vdrop(vp);
|
|
}
|
|
|
|
/*
|
|
* Lookup an entry in the cache
|
|
*
|
|
* Lookup is called with dvp pointing to the directory to search,
|
|
* cnp pointing to the name of the entry being sought. If the lookup
|
|
* succeeds, the vnode is returned in *vpp, and a status of -1 is
|
|
* returned. If the lookup determines that the name does not exist
|
|
* (negative cacheing), a status of ENOENT is returned. If the lookup
|
|
* fails, a status of zero is returned. If the directory vnode is
|
|
* recycled out from under us due to a forced unmount, a status of
|
|
* ENOENT is returned.
|
|
*
|
|
* vpp is locked and ref'd on return. If we're looking up DOTDOT, dvp is
|
|
* unlocked. If we're looking up . an extra ref is taken, but the lock is
|
|
* not recursively acquired.
|
|
*/
|
|
|
|
int
|
|
cache_lookup(dvp, vpp, cnp)
|
|
struct vnode *dvp;
|
|
struct vnode **vpp;
|
|
struct componentname *cnp;
|
|
{
|
|
struct namecache *ncp;
|
|
u_int32_t hash;
|
|
int error, ltype, wlocked;
|
|
|
|
if (!doingcache) {
|
|
cnp->cn_flags &= ~MAKEENTRY;
|
|
return (0);
|
|
}
|
|
retry:
|
|
CACHE_RLOCK();
|
|
wlocked = 0;
|
|
numcalls++;
|
|
error = 0;
|
|
|
|
retry_wlocked:
|
|
if (cnp->cn_nameptr[0] == '.') {
|
|
if (cnp->cn_namelen == 1) {
|
|
*vpp = dvp;
|
|
CTR2(KTR_VFS, "cache_lookup(%p, %s) found via .",
|
|
dvp, cnp->cn_nameptr);
|
|
dothits++;
|
|
goto success;
|
|
}
|
|
if (cnp->cn_namelen == 2 && cnp->cn_nameptr[1] == '.') {
|
|
dotdothits++;
|
|
if (dvp->v_cache_dd == NULL)
|
|
goto unlock;
|
|
if ((cnp->cn_flags & MAKEENTRY) == 0) {
|
|
if (dvp->v_cache_dd->nc_flag & NCF_ISDOTDOT)
|
|
cache_zap(dvp->v_cache_dd);
|
|
dvp->v_cache_dd = NULL;
|
|
goto unlock;
|
|
}
|
|
if (dvp->v_cache_dd->nc_flag & NCF_ISDOTDOT)
|
|
*vpp = dvp->v_cache_dd->nc_vp;
|
|
else
|
|
*vpp = dvp->v_cache_dd->nc_dvp;
|
|
CTR3(KTR_VFS, "cache_lookup(%p, %s) found %p via ..",
|
|
dvp, cnp->cn_nameptr, *vpp);
|
|
goto success;
|
|
}
|
|
}
|
|
|
|
hash = fnv_32_buf(cnp->cn_nameptr, cnp->cn_namelen, FNV1_32_INIT);
|
|
hash = fnv_32_buf(&dvp, sizeof(dvp), hash);
|
|
LIST_FOREACH(ncp, (NCHHASH(hash)), nc_hash) {
|
|
numchecks++;
|
|
if (ncp->nc_dvp == dvp && ncp->nc_nlen == cnp->cn_namelen &&
|
|
!bcmp(ncp->nc_name, cnp->cn_nameptr, ncp->nc_nlen))
|
|
break;
|
|
}
|
|
|
|
/* We failed to find an entry */
|
|
if (ncp == NULL) {
|
|
if ((cnp->cn_flags & MAKEENTRY) == 0) {
|
|
nummisszap++;
|
|
} else {
|
|
nummiss++;
|
|
}
|
|
nchstats.ncs_miss++;
|
|
goto unlock;
|
|
}
|
|
|
|
/* We don't want to have an entry, so dump it */
|
|
if ((cnp->cn_flags & MAKEENTRY) == 0) {
|
|
numposzaps++;
|
|
nchstats.ncs_badhits++;
|
|
if (!wlocked && !CACHE_UPGRADE_LOCK())
|
|
goto wlock;
|
|
cache_zap(ncp);
|
|
CACHE_WUNLOCK();
|
|
return (0);
|
|
}
|
|
|
|
/* We found a "positive" match, return the vnode */
|
|
if (ncp->nc_vp) {
|
|
numposhits++;
|
|
nchstats.ncs_goodhits++;
|
|
*vpp = ncp->nc_vp;
|
|
CTR4(KTR_VFS, "cache_lookup(%p, %s) found %p via ncp %p",
|
|
dvp, cnp->cn_nameptr, *vpp, ncp);
|
|
goto success;
|
|
}
|
|
|
|
/* We found a negative match, and want to create it, so purge */
|
|
if (cnp->cn_nameiop == CREATE) {
|
|
numnegzaps++;
|
|
nchstats.ncs_badhits++;
|
|
if (!wlocked && !CACHE_UPGRADE_LOCK())
|
|
goto wlock;
|
|
cache_zap(ncp);
|
|
CACHE_WUNLOCK();
|
|
return (0);
|
|
}
|
|
|
|
if (!wlocked && !CACHE_UPGRADE_LOCK())
|
|
goto wlock;
|
|
numneghits++;
|
|
/*
|
|
* We found a "negative" match, so we shift it to the end of
|
|
* the "negative" cache entries queue to satisfy LRU. Also,
|
|
* check to see if the entry is a whiteout; indicate this to
|
|
* the componentname, if so.
|
|
*/
|
|
TAILQ_REMOVE(&ncneg, ncp, nc_dst);
|
|
TAILQ_INSERT_TAIL(&ncneg, ncp, nc_dst);
|
|
nchstats.ncs_neghits++;
|
|
if (ncp->nc_flag & NCF_WHITE)
|
|
cnp->cn_flags |= ISWHITEOUT;
|
|
CACHE_WUNLOCK();
|
|
return (ENOENT);
|
|
|
|
wlock:
|
|
/*
|
|
* We need to update the cache after our lookup, so upgrade to
|
|
* a write lock and retry the operation.
|
|
*/
|
|
CACHE_RUNLOCK();
|
|
CACHE_WLOCK();
|
|
numupgrades++;
|
|
wlocked = 1;
|
|
goto retry_wlocked;
|
|
|
|
success:
|
|
/*
|
|
* On success we return a locked and ref'd vnode as per the lookup
|
|
* protocol.
|
|
*/
|
|
if (dvp == *vpp) { /* lookup on "." */
|
|
VREF(*vpp);
|
|
if (wlocked)
|
|
CACHE_WUNLOCK();
|
|
else
|
|
CACHE_RUNLOCK();
|
|
/*
|
|
* When we lookup "." we still can be asked to lock it
|
|
* differently...
|
|
*/
|
|
ltype = cnp->cn_lkflags & LK_TYPE_MASK;
|
|
if (ltype != VOP_ISLOCKED(*vpp)) {
|
|
if (ltype == LK_EXCLUSIVE) {
|
|
vn_lock(*vpp, LK_UPGRADE | LK_RETRY);
|
|
if ((*vpp)->v_iflag & VI_DOOMED) {
|
|
/* forced unmount */
|
|
vrele(*vpp);
|
|
*vpp = NULL;
|
|
return (ENOENT);
|
|
}
|
|
} else
|
|
vn_lock(*vpp, LK_DOWNGRADE | LK_RETRY);
|
|
}
|
|
return (-1);
|
|
}
|
|
ltype = 0; /* silence gcc warning */
|
|
if (cnp->cn_flags & ISDOTDOT) {
|
|
ltype = VOP_ISLOCKED(dvp);
|
|
VOP_UNLOCK(dvp, 0);
|
|
}
|
|
VI_LOCK(*vpp);
|
|
if (wlocked)
|
|
CACHE_WUNLOCK();
|
|
else
|
|
CACHE_RUNLOCK();
|
|
error = vget(*vpp, cnp->cn_lkflags | LK_INTERLOCK, cnp->cn_thread);
|
|
if (cnp->cn_flags & ISDOTDOT)
|
|
vn_lock(dvp, ltype | LK_RETRY);
|
|
if (error) {
|
|
*vpp = NULL;
|
|
goto retry;
|
|
}
|
|
if ((cnp->cn_flags & ISLASTCN) &&
|
|
(cnp->cn_lkflags & LK_TYPE_MASK) == LK_EXCLUSIVE) {
|
|
ASSERT_VOP_ELOCKED(*vpp, "cache_lookup");
|
|
}
|
|
return (-1);
|
|
|
|
unlock:
|
|
if (wlocked)
|
|
CACHE_WUNLOCK();
|
|
else
|
|
CACHE_RUNLOCK();
|
|
return (0);
|
|
}
|
|
|
|
/*
|
|
* Add an entry to the cache.
|
|
*/
|
|
void
|
|
cache_enter(dvp, vp, cnp)
|
|
struct vnode *dvp;
|
|
struct vnode *vp;
|
|
struct componentname *cnp;
|
|
{
|
|
struct namecache *ncp, *n2;
|
|
struct nchashhead *ncpp;
|
|
u_int32_t hash;
|
|
int flag;
|
|
int hold;
|
|
int zap;
|
|
int len;
|
|
|
|
CTR3(KTR_VFS, "cache_enter(%p, %p, %s)", dvp, vp, cnp->cn_nameptr);
|
|
VNASSERT(vp == NULL || (vp->v_iflag & VI_DOOMED) == 0, vp,
|
|
("cahe_enter: Adding a doomed vnode"));
|
|
|
|
if (!doingcache)
|
|
return;
|
|
|
|
/*
|
|
* Avoid blowout in namecache entries.
|
|
*/
|
|
if (numcache >= desiredvnodes * 2)
|
|
return;
|
|
|
|
flag = 0;
|
|
if (cnp->cn_nameptr[0] == '.') {
|
|
if (cnp->cn_namelen == 1)
|
|
return;
|
|
if (cnp->cn_namelen == 2 && cnp->cn_nameptr[1] == '.') {
|
|
CACHE_WLOCK();
|
|
/*
|
|
* If dotdot entry already exists, just retarget it
|
|
* to new parent vnode, otherwise continue with new
|
|
* namecache entry allocation.
|
|
*/
|
|
if ((ncp = dvp->v_cache_dd) != NULL) {
|
|
if (ncp->nc_flag & NCF_ISDOTDOT) {
|
|
KASSERT(ncp->nc_dvp == dvp,
|
|
("wrong isdotdot parent"));
|
|
TAILQ_REMOVE(&ncp->nc_vp->v_cache_dst,
|
|
ncp, nc_dst);
|
|
TAILQ_INSERT_HEAD(&vp->v_cache_dst,
|
|
ncp, nc_dst);
|
|
ncp->nc_vp = vp;
|
|
CACHE_WUNLOCK();
|
|
return;
|
|
}
|
|
}
|
|
dvp->v_cache_dd = NULL;
|
|
CACHE_WUNLOCK();
|
|
flag = NCF_ISDOTDOT;
|
|
}
|
|
}
|
|
|
|
hold = 0;
|
|
zap = 0;
|
|
|
|
/*
|
|
* Calculate the hash key and setup as much of the new
|
|
* namecache entry as possible before acquiring the lock.
|
|
*/
|
|
ncp = cache_alloc(cnp->cn_namelen);
|
|
ncp->nc_vp = vp;
|
|
ncp->nc_dvp = dvp;
|
|
ncp->nc_flag = flag;
|
|
len = ncp->nc_nlen = cnp->cn_namelen;
|
|
hash = fnv_32_buf(cnp->cn_nameptr, len, FNV1_32_INIT);
|
|
bcopy(cnp->cn_nameptr, ncp->nc_name, len);
|
|
hash = fnv_32_buf(&dvp, sizeof(dvp), hash);
|
|
CACHE_WLOCK();
|
|
|
|
/*
|
|
* See if this vnode or negative entry is already in the cache
|
|
* with this name. This can happen with concurrent lookups of
|
|
* the same path name.
|
|
*/
|
|
ncpp = NCHHASH(hash);
|
|
LIST_FOREACH(n2, ncpp, nc_hash) {
|
|
if (n2->nc_dvp == dvp &&
|
|
n2->nc_nlen == cnp->cn_namelen &&
|
|
!bcmp(n2->nc_name, cnp->cn_nameptr, n2->nc_nlen)) {
|
|
CACHE_WUNLOCK();
|
|
cache_free(ncp);
|
|
return;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* See if we are trying to add .. entry, but some other lookup
|
|
* has populated v_cache_dd pointer already.
|
|
*/
|
|
if (flag == NCF_ISDOTDOT && dvp->v_cache_dd != NULL) {
|
|
CACHE_WUNLOCK();
|
|
cache_free(ncp);
|
|
return;
|
|
}
|
|
|
|
numcache++;
|
|
if (!vp) {
|
|
numneg++;
|
|
if (cnp->cn_flags & ISWHITEOUT)
|
|
ncp->nc_flag |= NCF_WHITE;
|
|
} else if (vp->v_type == VDIR) {
|
|
if (flag == NCF_ISDOTDOT) {
|
|
KASSERT(dvp->v_cache_dd == NULL,
|
|
("dangling v_cache_dd"));
|
|
dvp->v_cache_dd = ncp;
|
|
} else {
|
|
if ((n2 = vp->v_cache_dd) != NULL &&
|
|
(n2->nc_flag & NCF_ISDOTDOT) != 0)
|
|
cache_zap(n2);
|
|
vp->v_cache_dd = ncp;
|
|
}
|
|
} else {
|
|
vp->v_cache_dd = NULL;
|
|
}
|
|
|
|
/*
|
|
* Insert the new namecache entry into the appropriate chain
|
|
* within the cache entries table.
|
|
*/
|
|
LIST_INSERT_HEAD(ncpp, ncp, nc_hash);
|
|
if (flag != NCF_ISDOTDOT) {
|
|
if (LIST_EMPTY(&dvp->v_cache_src)) {
|
|
hold = 1;
|
|
numcachehv++;
|
|
}
|
|
LIST_INSERT_HEAD(&dvp->v_cache_src, ncp, nc_src);
|
|
}
|
|
|
|
/*
|
|
* If the entry is "negative", we place it into the
|
|
* "negative" cache queue, otherwise, we place it into the
|
|
* destination vnode's cache entries queue.
|
|
*/
|
|
if (vp) {
|
|
TAILQ_INSERT_HEAD(&vp->v_cache_dst, ncp, nc_dst);
|
|
} else {
|
|
TAILQ_INSERT_TAIL(&ncneg, ncp, nc_dst);
|
|
}
|
|
if (numneg * ncnegfactor > numcache) {
|
|
ncp = TAILQ_FIRST(&ncneg);
|
|
zap = 1;
|
|
}
|
|
if (hold)
|
|
vhold(dvp);
|
|
if (zap)
|
|
cache_zap(ncp);
|
|
CACHE_WUNLOCK();
|
|
}
|
|
|
|
/*
|
|
* Name cache initialization, from vfs_init() when we are booting
|
|
*/
|
|
static void
|
|
nchinit(void *dummy __unused)
|
|
{
|
|
|
|
TAILQ_INIT(&ncneg);
|
|
|
|
cache_zone_small = uma_zcreate("S VFS Cache", CACHE_ZONE_SMALL, NULL,
|
|
NULL, NULL, NULL, UMA_ALIGN_PTR, UMA_ZONE_ZINIT);
|
|
cache_zone_large = uma_zcreate("L VFS Cache", CACHE_ZONE_LARGE, NULL,
|
|
NULL, NULL, NULL, UMA_ALIGN_PTR, UMA_ZONE_ZINIT);
|
|
|
|
nchashtbl = hashinit(desiredvnodes * 2, M_VFSCACHE, &nchash);
|
|
}
|
|
SYSINIT(vfs, SI_SUB_VFS, SI_ORDER_SECOND, nchinit, NULL);
|
|
|
|
|
|
/*
|
|
* Invalidate all entries to a particular vnode.
|
|
*/
|
|
void
|
|
cache_purge(vp)
|
|
struct vnode *vp;
|
|
{
|
|
|
|
CTR1(KTR_VFS, "cache_purge(%p)", vp);
|
|
CACHE_WLOCK();
|
|
while (!LIST_EMPTY(&vp->v_cache_src))
|
|
cache_zap(LIST_FIRST(&vp->v_cache_src));
|
|
while (!TAILQ_EMPTY(&vp->v_cache_dst))
|
|
cache_zap(TAILQ_FIRST(&vp->v_cache_dst));
|
|
if (vp->v_cache_dd != NULL) {
|
|
KASSERT(vp->v_cache_dd->nc_flag & NCF_ISDOTDOT,
|
|
("lost dotdot link"));
|
|
cache_zap(vp->v_cache_dd);
|
|
}
|
|
KASSERT(vp->v_cache_dd == NULL, ("incomplete purge"));
|
|
CACHE_WUNLOCK();
|
|
}
|
|
|
|
/*
|
|
* Invalidate all negative entries for a particular directory vnode.
|
|
*/
|
|
void
|
|
cache_purge_negative(vp)
|
|
struct vnode *vp;
|
|
{
|
|
struct namecache *cp, *ncp;
|
|
|
|
CTR1(KTR_VFS, "cache_purge_negative(%p)", vp);
|
|
CACHE_WLOCK();
|
|
LIST_FOREACH_SAFE(cp, &vp->v_cache_src, nc_src, ncp) {
|
|
if (cp->nc_vp == NULL)
|
|
cache_zap(cp);
|
|
}
|
|
CACHE_WUNLOCK();
|
|
}
|
|
|
|
/*
|
|
* Flush all entries referencing a particular filesystem.
|
|
*/
|
|
void
|
|
cache_purgevfs(mp)
|
|
struct mount *mp;
|
|
{
|
|
struct nchashhead *ncpp;
|
|
struct namecache *ncp, *nnp;
|
|
|
|
/* Scan hash tables for applicable entries */
|
|
CACHE_WLOCK();
|
|
for (ncpp = &nchashtbl[nchash]; ncpp >= nchashtbl; ncpp--) {
|
|
LIST_FOREACH_SAFE(ncp, ncpp, nc_hash, nnp) {
|
|
if (ncp->nc_dvp->v_mount == mp)
|
|
cache_zap(ncp);
|
|
}
|
|
}
|
|
CACHE_WUNLOCK();
|
|
}
|
|
|
|
/*
|
|
* Perform canonical checks and cache lookup and pass on to filesystem
|
|
* through the vop_cachedlookup only if needed.
|
|
*/
|
|
|
|
int
|
|
vfs_cache_lookup(ap)
|
|
struct vop_lookup_args /* {
|
|
struct vnode *a_dvp;
|
|
struct vnode **a_vpp;
|
|
struct componentname *a_cnp;
|
|
} */ *ap;
|
|
{
|
|
struct vnode *dvp;
|
|
int error;
|
|
struct vnode **vpp = ap->a_vpp;
|
|
struct componentname *cnp = ap->a_cnp;
|
|
struct ucred *cred = cnp->cn_cred;
|
|
int flags = cnp->cn_flags;
|
|
struct thread *td = cnp->cn_thread;
|
|
|
|
*vpp = NULL;
|
|
dvp = ap->a_dvp;
|
|
|
|
if (dvp->v_type != VDIR)
|
|
return (ENOTDIR);
|
|
|
|
if ((flags & ISLASTCN) && (dvp->v_mount->mnt_flag & MNT_RDONLY) &&
|
|
(cnp->cn_nameiop == DELETE || cnp->cn_nameiop == RENAME))
|
|
return (EROFS);
|
|
|
|
error = VOP_ACCESS(dvp, VEXEC, cred, td);
|
|
if (error)
|
|
return (error);
|
|
|
|
error = cache_lookup(dvp, vpp, cnp);
|
|
if (error == 0)
|
|
return (VOP_CACHEDLOOKUP(dvp, vpp, cnp));
|
|
if (error == -1)
|
|
return (0);
|
|
return (error);
|
|
}
|
|
|
|
|
|
#ifndef _SYS_SYSPROTO_H_
|
|
struct __getcwd_args {
|
|
u_char *buf;
|
|
u_int buflen;
|
|
};
|
|
#endif
|
|
|
|
/*
|
|
* XXX All of these sysctls would probably be more productive dead.
|
|
*/
|
|
static int disablecwd;
|
|
SYSCTL_INT(_debug, OID_AUTO, disablecwd, CTLFLAG_RW, &disablecwd, 0,
|
|
"Disable the getcwd syscall");
|
|
|
|
/* Implementation of the getcwd syscall. */
|
|
int
|
|
__getcwd(td, uap)
|
|
struct thread *td;
|
|
struct __getcwd_args *uap;
|
|
{
|
|
|
|
return (kern___getcwd(td, uap->buf, UIO_USERSPACE, uap->buflen));
|
|
}
|
|
|
|
int
|
|
kern___getcwd(struct thread *td, u_char *buf, enum uio_seg bufseg, u_int buflen)
|
|
{
|
|
char *bp, *tmpbuf;
|
|
struct filedesc *fdp;
|
|
struct vnode *cdir, *rdir;
|
|
int error, vfslocked;
|
|
|
|
if (disablecwd)
|
|
return (ENODEV);
|
|
if (buflen < 2)
|
|
return (EINVAL);
|
|
if (buflen > MAXPATHLEN)
|
|
buflen = MAXPATHLEN;
|
|
|
|
tmpbuf = malloc(buflen, M_TEMP, M_WAITOK);
|
|
fdp = td->td_proc->p_fd;
|
|
FILEDESC_SLOCK(fdp);
|
|
cdir = fdp->fd_cdir;
|
|
VREF(cdir);
|
|
rdir = fdp->fd_rdir;
|
|
VREF(rdir);
|
|
FILEDESC_SUNLOCK(fdp);
|
|
error = vn_fullpath1(td, cdir, rdir, tmpbuf, &bp, buflen);
|
|
vfslocked = VFS_LOCK_GIANT(rdir->v_mount);
|
|
vrele(rdir);
|
|
VFS_UNLOCK_GIANT(vfslocked);
|
|
vfslocked = VFS_LOCK_GIANT(cdir->v_mount);
|
|
vrele(cdir);
|
|
VFS_UNLOCK_GIANT(vfslocked);
|
|
|
|
if (!error) {
|
|
if (bufseg == UIO_SYSSPACE)
|
|
bcopy(bp, buf, strlen(bp) + 1);
|
|
else
|
|
error = copyout(bp, buf, strlen(bp) + 1);
|
|
#ifdef KTRACE
|
|
if (KTRPOINT(curthread, KTR_NAMEI))
|
|
ktrnamei(bp);
|
|
#endif
|
|
}
|
|
free(tmpbuf, M_TEMP);
|
|
return (error);
|
|
}
|
|
|
|
/*
|
|
* Thus begins the fullpath magic.
|
|
*/
|
|
|
|
#undef STATNODE
|
|
#define STATNODE(name) \
|
|
static u_int name; \
|
|
SYSCTL_UINT(_vfs_cache, OID_AUTO, name, CTLFLAG_RD, &name, 0, "")
|
|
|
|
static int disablefullpath;
|
|
SYSCTL_INT(_debug, OID_AUTO, disablefullpath, CTLFLAG_RW, &disablefullpath, 0,
|
|
"Disable the vn_fullpath function");
|
|
|
|
/* These count for kern___getcwd(), too. */
|
|
STATNODE(numfullpathcalls);
|
|
STATNODE(numfullpathfail1);
|
|
STATNODE(numfullpathfail2);
|
|
STATNODE(numfullpathfail4);
|
|
STATNODE(numfullpathfound);
|
|
|
|
/*
|
|
* Retrieve the full filesystem path that correspond to a vnode from the name
|
|
* cache (if available)
|
|
*/
|
|
int
|
|
vn_fullpath(struct thread *td, struct vnode *vn, char **retbuf, char **freebuf)
|
|
{
|
|
char *buf;
|
|
struct filedesc *fdp;
|
|
struct vnode *rdir;
|
|
int error, vfslocked;
|
|
|
|
if (disablefullpath)
|
|
return (ENODEV);
|
|
if (vn == NULL)
|
|
return (EINVAL);
|
|
|
|
buf = malloc(MAXPATHLEN, M_TEMP, M_WAITOK);
|
|
fdp = td->td_proc->p_fd;
|
|
FILEDESC_SLOCK(fdp);
|
|
rdir = fdp->fd_rdir;
|
|
VREF(rdir);
|
|
FILEDESC_SUNLOCK(fdp);
|
|
error = vn_fullpath1(td, vn, rdir, buf, retbuf, MAXPATHLEN);
|
|
vfslocked = VFS_LOCK_GIANT(rdir->v_mount);
|
|
vrele(rdir);
|
|
VFS_UNLOCK_GIANT(vfslocked);
|
|
|
|
if (!error)
|
|
*freebuf = buf;
|
|
else
|
|
free(buf, M_TEMP);
|
|
return (error);
|
|
}
|
|
|
|
/*
|
|
* This function is similar to vn_fullpath, but it attempts to lookup the
|
|
* pathname relative to the global root mount point. This is required for the
|
|
* auditing sub-system, as audited pathnames must be absolute, relative to the
|
|
* global root mount point.
|
|
*/
|
|
int
|
|
vn_fullpath_global(struct thread *td, struct vnode *vn,
|
|
char **retbuf, char **freebuf)
|
|
{
|
|
char *buf;
|
|
int error;
|
|
|
|
if (disablefullpath)
|
|
return (ENODEV);
|
|
if (vn == NULL)
|
|
return (EINVAL);
|
|
buf = malloc(MAXPATHLEN, M_TEMP, M_WAITOK);
|
|
error = vn_fullpath1(td, vn, rootvnode, buf, retbuf, MAXPATHLEN);
|
|
if (!error)
|
|
*freebuf = buf;
|
|
else
|
|
free(buf, M_TEMP);
|
|
return (error);
|
|
}
|
|
|
|
static int
|
|
vn_vptocnp(struct vnode **vp, char **bp, char *buf, u_int *buflen)
|
|
{
|
|
struct vnode *dvp;
|
|
int error, vfslocked;
|
|
|
|
vhold(*vp);
|
|
CACHE_RUNLOCK();
|
|
vfslocked = VFS_LOCK_GIANT((*vp)->v_mount);
|
|
vn_lock(*vp, LK_SHARED | LK_RETRY);
|
|
error = VOP_VPTOCNP(*vp, &dvp, buf, buflen);
|
|
VOP_UNLOCK(*vp, 0);
|
|
vdrop(*vp);
|
|
VFS_UNLOCK_GIANT(vfslocked);
|
|
if (error) {
|
|
numfullpathfail2++;
|
|
return (error);
|
|
}
|
|
*bp = buf + *buflen;
|
|
*vp = dvp;
|
|
CACHE_RLOCK();
|
|
if ((*vp)->v_iflag & VI_DOOMED) {
|
|
/* forced unmount */
|
|
CACHE_RUNLOCK();
|
|
vdrop(*vp);
|
|
return (ENOENT);
|
|
}
|
|
vdrop(*vp);
|
|
|
|
return (0);
|
|
}
|
|
|
|
/*
|
|
* The magic behind kern___getcwd() and vn_fullpath().
|
|
*/
|
|
static int
|
|
vn_fullpath1(struct thread *td, struct vnode *vp, struct vnode *rdir,
|
|
char *buf, char **retbuf, u_int buflen)
|
|
{
|
|
char *bp;
|
|
int error, i, slash_prefixed;
|
|
struct namecache *ncp;
|
|
|
|
buflen--;
|
|
bp = buf + buflen;
|
|
*bp = '\0';
|
|
error = 0;
|
|
slash_prefixed = 0;
|
|
|
|
CACHE_RLOCK();
|
|
numfullpathcalls++;
|
|
if (vp->v_type != VDIR) {
|
|
ncp = TAILQ_FIRST(&vp->v_cache_dst);
|
|
if (ncp != NULL) {
|
|
buflen -= ncp->nc_nlen;
|
|
for (i = ncp->nc_nlen - 1; i >= 0 && bp != buf; i--)
|
|
*--bp = ncp->nc_name[i];
|
|
if (bp == buf) {
|
|
numfullpathfail4++;
|
|
CACHE_RUNLOCK();
|
|
return (ENOMEM);
|
|
}
|
|
vp = ncp->nc_dvp;
|
|
} else {
|
|
error = vn_vptocnp(&vp, &bp, buf, &buflen);
|
|
if (error)
|
|
return (error);
|
|
}
|
|
if (buflen <= 0) {
|
|
numfullpathfail4++;
|
|
CACHE_RUNLOCK();
|
|
return (ENOMEM);
|
|
}
|
|
*--bp = '/';
|
|
buflen--;
|
|
slash_prefixed = 1;
|
|
}
|
|
while (vp != rdir && vp != rootvnode) {
|
|
if (vp->v_vflag & VV_ROOT) {
|
|
if (vp->v_iflag & VI_DOOMED) { /* forced unmount */
|
|
CACHE_RUNLOCK();
|
|
error = ENOENT;
|
|
break;
|
|
}
|
|
vp = vp->v_mount->mnt_vnodecovered;
|
|
continue;
|
|
}
|
|
if (vp->v_type != VDIR) {
|
|
numfullpathfail1++;
|
|
CACHE_RUNLOCK();
|
|
error = ENOTDIR;
|
|
break;
|
|
}
|
|
TAILQ_FOREACH(ncp, &vp->v_cache_dst, nc_dst)
|
|
if ((ncp->nc_flag & NCF_ISDOTDOT) == 0)
|
|
break;
|
|
if (ncp != NULL) {
|
|
buflen -= ncp->nc_nlen;
|
|
for (i = ncp->nc_nlen - 1; i >= 0 && bp != buf; i--)
|
|
*--bp = ncp->nc_name[i];
|
|
if (bp == buf) {
|
|
numfullpathfail4++;
|
|
CACHE_RUNLOCK();
|
|
error = ENOMEM;
|
|
break;
|
|
}
|
|
vp = ncp->nc_dvp;
|
|
} else {
|
|
error = vn_vptocnp(&vp, &bp, buf, &buflen);
|
|
if (error)
|
|
break;
|
|
}
|
|
if (buflen <= 0) {
|
|
numfullpathfail4++;
|
|
CACHE_RUNLOCK();
|
|
error = ENOMEM;
|
|
break;
|
|
}
|
|
*--bp = '/';
|
|
buflen--;
|
|
slash_prefixed = 1;
|
|
}
|
|
if (error)
|
|
return (error);
|
|
if (!slash_prefixed) {
|
|
if (bp == buf) {
|
|
numfullpathfail4++;
|
|
CACHE_RUNLOCK();
|
|
return (ENOMEM);
|
|
} else
|
|
*--bp = '/';
|
|
}
|
|
numfullpathfound++;
|
|
CACHE_RUNLOCK();
|
|
|
|
*retbuf = bp;
|
|
return (0);
|
|
}
|
|
|
|
int
|
|
vn_commname(struct vnode *vp, char *buf, u_int buflen)
|
|
{
|
|
struct namecache *ncp;
|
|
int l;
|
|
|
|
CACHE_RLOCK();
|
|
TAILQ_FOREACH(ncp, &vp->v_cache_dst, nc_dst)
|
|
if ((ncp->nc_flag & NCF_ISDOTDOT) == 0)
|
|
break;
|
|
if (ncp == NULL) {
|
|
CACHE_RUNLOCK();
|
|
return (ENOENT);
|
|
}
|
|
l = min(ncp->nc_nlen, buflen - 1);
|
|
memcpy(buf, ncp->nc_name, l);
|
|
CACHE_RUNLOCK();
|
|
buf[l] = '\0';
|
|
return (0);
|
|
}
|