Previously it would check 4, 3, 2, 1 lists. In practice by the time it is getting called all lists have some elements and consequently this does not result in new evictions. Nonetheless, the code is clearer. Tested by: pho
2838 lines
70 KiB
C
2838 lines
70 KiB
C
/*-
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* SPDX-License-Identifier: BSD-3-Clause
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*
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* Copyright (c) 1989, 1993, 1995
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* The Regents of the University of California. All rights reserved.
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*
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* This code is derived from software contributed to Berkeley by
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* Poul-Henning Kamp of the FreeBSD Project.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. 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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*
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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
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* 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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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include "opt_ddb.h"
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#include "opt_ktrace.h"
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/capsicum.h>
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#include <sys/counter.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/ktr.h>
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#include <sys/lock.h>
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#include <sys/malloc.h>
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#include <sys/fcntl.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/sdt.h>
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#include <sys/smr.h>
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#include <sys/smp.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/vnode.h>
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#include <ck_queue.h>
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#ifdef KTRACE
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#include <sys/ktrace.h>
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#endif
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#ifdef DDB
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#include <ddb/ddb.h>
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#endif
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#include <vm/uma.h>
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SDT_PROVIDER_DECLARE(vfs);
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SDT_PROBE_DEFINE3(vfs, namecache, enter, done, "struct vnode *", "char *",
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"struct vnode *");
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SDT_PROBE_DEFINE2(vfs, namecache, enter_negative, done, "struct vnode *",
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"char *");
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SDT_PROBE_DEFINE1(vfs, namecache, fullpath, entry, "struct vnode *");
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SDT_PROBE_DEFINE3(vfs, namecache, fullpath, hit, "struct vnode *",
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"char *", "struct vnode *");
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SDT_PROBE_DEFINE1(vfs, namecache, fullpath, miss, "struct vnode *");
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SDT_PROBE_DEFINE3(vfs, namecache, fullpath, return, "int",
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"struct vnode *", "char *");
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SDT_PROBE_DEFINE3(vfs, namecache, lookup, hit, "struct vnode *", "char *",
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"struct vnode *");
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SDT_PROBE_DEFINE2(vfs, namecache, lookup, hit__negative,
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"struct vnode *", "char *");
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SDT_PROBE_DEFINE2(vfs, namecache, lookup, miss, "struct vnode *",
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"char *");
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SDT_PROBE_DEFINE1(vfs, namecache, purge, done, "struct vnode *");
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SDT_PROBE_DEFINE1(vfs, namecache, purge_negative, done, "struct vnode *");
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SDT_PROBE_DEFINE1(vfs, namecache, purgevfs, done, "struct mount *");
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SDT_PROBE_DEFINE3(vfs, namecache, zap, done, "struct vnode *", "char *",
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"struct vnode *");
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SDT_PROBE_DEFINE2(vfs, namecache, zap_negative, done, "struct vnode *",
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"char *");
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SDT_PROBE_DEFINE2(vfs, namecache, shrink_negative, done, "struct vnode *",
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"char *");
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/*
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* This structure describes the elements in the cache of recent
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* names looked up by namei.
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*/
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struct negstate {
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u_char neg_flag;
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};
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_Static_assert(sizeof(struct negstate) <= sizeof(struct vnode *),
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"the state must fit in a union with a pointer without growing it");
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struct namecache {
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CK_LIST_ENTRY(namecache) nc_hash;/* hash chain */
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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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union {
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struct vnode *nu_vp; /* vnode the name refers to */
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struct negstate nu_neg;/* negative entry state */
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} n_un;
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u_char nc_flag; /* flag bits */
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u_char nc_nlen; /* length of name */
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char nc_name[0]; /* segment name + nul */
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};
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/*
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* struct namecache_ts repeats struct namecache layout up to the
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* nc_nlen member.
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* struct namecache_ts is used in place of struct namecache when time(s) need
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* to be stored. The nc_dotdottime field is used when a cache entry is mapping
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* both a non-dotdot directory name plus dotdot for the directory's
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* parent.
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*/
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struct namecache_ts {
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struct timespec nc_time; /* timespec provided by fs */
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struct timespec nc_dotdottime; /* dotdot timespec provided by fs */
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int nc_ticks; /* ticks value when entry was added */
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struct namecache nc_nc;
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};
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#define nc_vp n_un.nu_vp
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#define nc_neg n_un.nu_neg
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/*
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* Flags in namecache.nc_flag
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*/
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#define NCF_WHITE 0x01
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#define NCF_ISDOTDOT 0x02
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#define NCF_TS 0x04
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#define NCF_DTS 0x08
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#define NCF_DVDROP 0x10
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#define NCF_NEGATIVE 0x20
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#define NCF_INVALID 0x40
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/*
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* Flags in negstate.neg_flag
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*/
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#define NEG_HOT 0x01
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/*
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* Mark an entry as invalid.
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*
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* This is called before it starts getting deconstructed.
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*/
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static void
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cache_ncp_invalidate(struct namecache *ncp)
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{
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KASSERT((ncp->nc_flag & NCF_INVALID) == 0,
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("%s: entry %p already invalid", __func__, ncp));
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ncp->nc_flag |= NCF_INVALID;
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atomic_thread_fence_rel();
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}
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/*
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* Verify validity of an entry.
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*
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* All places which elide locks are supposed to call this after they are
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* done with reading from an entry.
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*/
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static bool
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cache_ncp_invalid(struct namecache *ncp)
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{
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atomic_thread_fence_acq();
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return ((ncp->nc_flag & NCF_INVALID) != 0);
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}
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/*
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* Name caching works as follows:
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*
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* Names found by directory scans are retained in a cache
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* for future reference. It is managed LRU, so frequently
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* used names will hang around. Cache is indexed by hash value
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* obtained from (dvp, name) where dvp refers to the directory
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* containing name.
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*
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* If it is a "negative" entry, (i.e. for a name that is known NOT to
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* exist) the vnode pointer will be NULL.
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*
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* Upon reaching the last segment of a path, if the reference
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* is for DELETE, or NOCACHE is set (rewrite), and the
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* name is located in the cache, it will be dropped.
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*
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* These locks are used (in the order in which they can be taken):
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* NAME TYPE ROLE
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* vnodelock mtx vnode lists and v_cache_dd field protection
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* bucketlock rwlock for access to given set of hash buckets
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* neglist mtx negative entry LRU management
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*
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* Additionally, ncneg_shrink_lock mtx is used to have at most one thread
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* shrinking the LRU list.
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*
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* It is legal to take multiple vnodelock and bucketlock locks. The locking
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* order is lower address first. Both are recursive.
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*
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* "." lookups are lockless.
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*
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* ".." and vnode -> name lookups require vnodelock.
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*
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* name -> vnode lookup requires the relevant bucketlock to be held for reading.
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*
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* Insertions and removals of entries require involved vnodes and bucketlocks
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* to be write-locked to prevent other threads from seeing the entry.
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*
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* Some lookups result in removal of the found entry (e.g. getting rid of a
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* negative entry with the intent to create a positive one), which poses a
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* problem when multiple threads reach the state. Similarly, two different
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* threads can purge two different vnodes and try to remove the same name.
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*
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* If the already held vnode lock is lower than the second required lock, we
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* can just take the other lock. However, in the opposite case, this could
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* deadlock. As such, this is resolved by trylocking and if that fails unlocking
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* the first node, locking everything in order and revalidating the state.
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*/
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VFS_SMR_DECLARE;
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/*
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* Structures associated with name caching.
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*/
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#define NCHHASH(hash) \
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(&nchashtbl[(hash) & nchash])
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static __read_mostly CK_LIST_HEAD(nchashhead, namecache) *nchashtbl;/* Hash Table */
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static u_long __read_mostly nchash; /* size of hash table */
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SYSCTL_ULONG(_debug, OID_AUTO, nchash, CTLFLAG_RD, &nchash, 0,
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"Size of namecache hash table");
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static u_long __read_mostly ncnegfactor = 5; /* ratio of negative entries */
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SYSCTL_ULONG(_vfs, OID_AUTO, ncnegfactor, CTLFLAG_RW, &ncnegfactor, 0,
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"Ratio of negative namecache entries");
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static u_long __exclusive_cache_line numneg; /* number of negative entries allocated */
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static u_long __exclusive_cache_line numcache;/* number of cache entries allocated */
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u_int ncsizefactor = 2;
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SYSCTL_UINT(_vfs, OID_AUTO, ncsizefactor, CTLFLAG_RW, &ncsizefactor, 0,
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"Size factor for namecache");
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static u_int __read_mostly ncpurgeminvnodes;
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SYSCTL_UINT(_vfs, OID_AUTO, ncpurgeminvnodes, CTLFLAG_RW, &ncpurgeminvnodes, 0,
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"Number of vnodes below which purgevfs ignores the request");
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static u_int __read_mostly ncsize; /* the size as computed on creation or resizing */
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struct nchstats nchstats; /* cache effectiveness statistics */
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static struct mtx __exclusive_cache_line ncneg_shrink_lock;
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struct neglist {
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struct mtx nl_lock;
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TAILQ_HEAD(, namecache) nl_list;
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} __aligned(CACHE_LINE_SIZE);
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static struct neglist __read_mostly *neglists;
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static struct neglist ncneg_hot;
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static u_long numhotneg;
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#define numneglists (ncneghash + 1)
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static u_int __read_mostly ncneghash;
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static inline struct neglist *
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NCP2NEGLIST(struct namecache *ncp)
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{
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return (&neglists[(((uintptr_t)(ncp) >> 8) & ncneghash)]);
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}
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static inline struct negstate *
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NCP2NEGSTATE(struct namecache *ncp)
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{
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MPASS(ncp->nc_flag & NCF_NEGATIVE);
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return (&ncp->nc_neg);
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}
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#define numbucketlocks (ncbuckethash + 1)
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static u_int __read_mostly ncbuckethash;
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static struct rwlock_padalign __read_mostly *bucketlocks;
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#define HASH2BUCKETLOCK(hash) \
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((struct rwlock *)(&bucketlocks[((hash) & ncbuckethash)]))
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#define numvnodelocks (ncvnodehash + 1)
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static u_int __read_mostly ncvnodehash;
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static struct mtx __read_mostly *vnodelocks;
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static inline struct mtx *
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VP2VNODELOCK(struct vnode *vp)
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{
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return (&vnodelocks[(((uintptr_t)(vp) >> 8) & ncvnodehash)]);
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}
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|
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/*
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* UMA zones for the VFS cache.
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*
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* The small cache is used for entries with short names, which are the
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* most common. The large cache is used for entries which are too big to
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* fit in the small cache.
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*/
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static uma_zone_t __read_mostly cache_zone_small;
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static uma_zone_t __read_mostly cache_zone_small_ts;
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static uma_zone_t __read_mostly cache_zone_large;
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static uma_zone_t __read_mostly cache_zone_large_ts;
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#define CACHE_PATH_CUTOFF 35
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static struct namecache *
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cache_alloc(int len, int ts)
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{
|
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struct namecache_ts *ncp_ts;
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struct namecache *ncp;
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if (__predict_false(ts)) {
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if (len <= CACHE_PATH_CUTOFF)
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ncp_ts = uma_zalloc_smr(cache_zone_small_ts, M_WAITOK);
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else
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ncp_ts = uma_zalloc_smr(cache_zone_large_ts, M_WAITOK);
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ncp = &ncp_ts->nc_nc;
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} else {
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if (len <= CACHE_PATH_CUTOFF)
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ncp = uma_zalloc_smr(cache_zone_small, M_WAITOK);
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else
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ncp = uma_zalloc_smr(cache_zone_large, M_WAITOK);
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}
|
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return (ncp);
|
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}
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|
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static void
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cache_free(struct namecache *ncp)
|
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{
|
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struct namecache_ts *ncp_ts;
|
|
|
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if (ncp == NULL)
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return;
|
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if ((ncp->nc_flag & NCF_DVDROP) != 0)
|
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vdrop(ncp->nc_dvp);
|
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if (__predict_false(ncp->nc_flag & NCF_TS)) {
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ncp_ts = __containerof(ncp, struct namecache_ts, nc_nc);
|
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if (ncp->nc_nlen <= CACHE_PATH_CUTOFF)
|
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uma_zfree_smr(cache_zone_small_ts, ncp_ts);
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else
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uma_zfree_smr(cache_zone_large_ts, ncp_ts);
|
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} else {
|
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if (ncp->nc_nlen <= CACHE_PATH_CUTOFF)
|
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uma_zfree_smr(cache_zone_small, ncp);
|
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else
|
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uma_zfree_smr(cache_zone_large, ncp);
|
|
}
|
|
}
|
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|
|
static void
|
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cache_out_ts(struct namecache *ncp, struct timespec *tsp, int *ticksp)
|
|
{
|
|
struct namecache_ts *ncp_ts;
|
|
|
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KASSERT((ncp->nc_flag & NCF_TS) != 0 ||
|
|
(tsp == NULL && ticksp == NULL),
|
|
("No NCF_TS"));
|
|
|
|
if (tsp == NULL && ticksp == NULL)
|
|
return;
|
|
|
|
ncp_ts = __containerof(ncp, struct namecache_ts, nc_nc);
|
|
if (tsp != NULL)
|
|
*tsp = ncp_ts->nc_time;
|
|
if (ticksp != NULL)
|
|
*ticksp = ncp_ts->nc_ticks;
|
|
}
|
|
|
|
#ifdef DEBUG_CACHE
|
|
static int __read_mostly doingcache = 1; /* 1 => enable the cache */
|
|
SYSCTL_INT(_debug, OID_AUTO, vfscache, CTLFLAG_RW, &doingcache, 0,
|
|
"VFS namecache enabled");
|
|
#endif
|
|
|
|
/* Export size information to userland */
|
|
SYSCTL_INT(_debug_sizeof, OID_AUTO, namecache, CTLFLAG_RD, SYSCTL_NULL_INT_PTR,
|
|
sizeof(struct namecache), "sizeof(struct namecache)");
|
|
|
|
/*
|
|
* The new name cache statistics
|
|
*/
|
|
static SYSCTL_NODE(_vfs, OID_AUTO, cache, CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
|
|
"Name cache statistics");
|
|
#define STATNODE_ULONG(name, descr) \
|
|
SYSCTL_ULONG(_vfs_cache, OID_AUTO, name, CTLFLAG_RD, &name, 0, descr);
|
|
#define STATNODE_COUNTER(name, descr) \
|
|
static COUNTER_U64_DEFINE_EARLY(name); \
|
|
SYSCTL_COUNTER_U64(_vfs_cache, OID_AUTO, name, CTLFLAG_RD, &name, \
|
|
descr);
|
|
STATNODE_ULONG(numneg, "Number of negative cache entries");
|
|
STATNODE_ULONG(numcache, "Number of cache entries");
|
|
STATNODE_COUNTER(numcachehv, "Number of namecache entries with vnodes held");
|
|
STATNODE_COUNTER(numdrops, "Number of dropped entries due to reaching the limit");
|
|
STATNODE_COUNTER(dothits, "Number of '.' hits");
|
|
STATNODE_COUNTER(dotdothits, "Number of '..' hits");
|
|
STATNODE_COUNTER(numchecks, "Number of checks in lookup");
|
|
STATNODE_COUNTER(nummiss, "Number of cache misses");
|
|
STATNODE_COUNTER(nummisszap, "Number of cache misses we do not want to cache");
|
|
STATNODE_COUNTER(numposzaps,
|
|
"Number of cache hits (positive) we do not want to cache");
|
|
STATNODE_COUNTER(numposhits, "Number of cache hits (positive)");
|
|
STATNODE_COUNTER(numnegzaps,
|
|
"Number of cache hits (negative) we do not want to cache");
|
|
STATNODE_COUNTER(numneghits, "Number of cache hits (negative)");
|
|
/* These count for vn_getcwd(), too. */
|
|
STATNODE_COUNTER(numfullpathcalls, "Number of fullpath search calls");
|
|
STATNODE_COUNTER(numfullpathfail1, "Number of fullpath search errors (ENOTDIR)");
|
|
STATNODE_COUNTER(numfullpathfail2,
|
|
"Number of fullpath search errors (VOP_VPTOCNP failures)");
|
|
STATNODE_COUNTER(numfullpathfail4, "Number of fullpath search errors (ENOMEM)");
|
|
STATNODE_COUNTER(numfullpathfound, "Number of successful fullpath calls");
|
|
STATNODE_COUNTER(zap_and_exit_bucket_relock_success,
|
|
"Number of successful removals after relocking");
|
|
static long zap_and_exit_bucket_fail; STATNODE_ULONG(zap_and_exit_bucket_fail,
|
|
"Number of times zap_and_exit failed to lock");
|
|
static long zap_and_exit_bucket_fail2; STATNODE_ULONG(zap_and_exit_bucket_fail2,
|
|
"Number of times zap_and_exit failed to lock");
|
|
static long cache_lock_vnodes_cel_3_failures;
|
|
STATNODE_ULONG(cache_lock_vnodes_cel_3_failures,
|
|
"Number of times 3-way vnode locking failed");
|
|
STATNODE_ULONG(numhotneg, "Number of hot negative entries");
|
|
STATNODE_COUNTER(numneg_evicted,
|
|
"Number of negative entries evicted when adding a new entry");
|
|
STATNODE_COUNTER(shrinking_skipped,
|
|
"Number of times shrinking was already in progress");
|
|
|
|
static void cache_zap_locked(struct namecache *ncp);
|
|
static int vn_fullpath_hardlink(struct thread *td, struct nameidata *ndp, char **retbuf,
|
|
char **freebuf, size_t *buflen);
|
|
static int vn_fullpath_any(struct thread *td, struct vnode *vp, struct vnode *rdir,
|
|
char *buf, char **retbuf, size_t *buflen);
|
|
static int vn_fullpath_dir(struct thread *td, struct vnode *vp, struct vnode *rdir,
|
|
char *buf, char **retbuf, size_t *len, bool slash_prefixed, size_t addend);
|
|
|
|
static MALLOC_DEFINE(M_VFSCACHE, "vfscache", "VFS name cache entries");
|
|
|
|
static int cache_yield;
|
|
SYSCTL_INT(_vfs_cache, OID_AUTO, yield, CTLFLAG_RD, &cache_yield, 0,
|
|
"Number of times cache called yield");
|
|
|
|
static void __noinline
|
|
cache_maybe_yield(void)
|
|
{
|
|
|
|
if (should_yield()) {
|
|
cache_yield++;
|
|
kern_yield(PRI_USER);
|
|
}
|
|
}
|
|
|
|
static inline void
|
|
cache_assert_vlp_locked(struct mtx *vlp)
|
|
{
|
|
|
|
if (vlp != NULL)
|
|
mtx_assert(vlp, MA_OWNED);
|
|
}
|
|
|
|
static inline void
|
|
cache_assert_vnode_locked(struct vnode *vp)
|
|
{
|
|
struct mtx *vlp;
|
|
|
|
vlp = VP2VNODELOCK(vp);
|
|
cache_assert_vlp_locked(vlp);
|
|
}
|
|
|
|
static uint32_t
|
|
cache_get_hash(char *name, u_char len, struct vnode *dvp)
|
|
{
|
|
uint32_t hash;
|
|
|
|
hash = fnv_32_buf(name, len, FNV1_32_INIT);
|
|
hash = fnv_32_buf(&dvp, sizeof(dvp), hash);
|
|
return (hash);
|
|
}
|
|
|
|
static inline struct rwlock *
|
|
NCP2BUCKETLOCK(struct namecache *ncp)
|
|
{
|
|
uint32_t hash;
|
|
|
|
hash = cache_get_hash(ncp->nc_name, ncp->nc_nlen, ncp->nc_dvp);
|
|
return (HASH2BUCKETLOCK(hash));
|
|
}
|
|
|
|
#ifdef INVARIANTS
|
|
static void
|
|
cache_assert_bucket_locked(struct namecache *ncp, int mode)
|
|
{
|
|
struct rwlock *blp;
|
|
|
|
blp = NCP2BUCKETLOCK(ncp);
|
|
rw_assert(blp, mode);
|
|
}
|
|
#else
|
|
#define cache_assert_bucket_locked(x, y) do { } while (0)
|
|
#endif
|
|
|
|
#define cache_sort_vnodes(x, y) _cache_sort_vnodes((void **)(x), (void **)(y))
|
|
static void
|
|
_cache_sort_vnodes(void **p1, void **p2)
|
|
{
|
|
void *tmp;
|
|
|
|
MPASS(*p1 != NULL || *p2 != NULL);
|
|
|
|
if (*p1 > *p2) {
|
|
tmp = *p2;
|
|
*p2 = *p1;
|
|
*p1 = tmp;
|
|
}
|
|
}
|
|
|
|
static void
|
|
cache_lock_all_buckets(void)
|
|
{
|
|
u_int i;
|
|
|
|
for (i = 0; i < numbucketlocks; i++)
|
|
rw_wlock(&bucketlocks[i]);
|
|
}
|
|
|
|
static void
|
|
cache_unlock_all_buckets(void)
|
|
{
|
|
u_int i;
|
|
|
|
for (i = 0; i < numbucketlocks; i++)
|
|
rw_wunlock(&bucketlocks[i]);
|
|
}
|
|
|
|
static void
|
|
cache_lock_all_vnodes(void)
|
|
{
|
|
u_int i;
|
|
|
|
for (i = 0; i < numvnodelocks; i++)
|
|
mtx_lock(&vnodelocks[i]);
|
|
}
|
|
|
|
static void
|
|
cache_unlock_all_vnodes(void)
|
|
{
|
|
u_int i;
|
|
|
|
for (i = 0; i < numvnodelocks; i++)
|
|
mtx_unlock(&vnodelocks[i]);
|
|
}
|
|
|
|
static int
|
|
cache_trylock_vnodes(struct mtx *vlp1, struct mtx *vlp2)
|
|
{
|
|
|
|
cache_sort_vnodes(&vlp1, &vlp2);
|
|
|
|
if (vlp1 != NULL) {
|
|
if (!mtx_trylock(vlp1))
|
|
return (EAGAIN);
|
|
}
|
|
if (!mtx_trylock(vlp2)) {
|
|
if (vlp1 != NULL)
|
|
mtx_unlock(vlp1);
|
|
return (EAGAIN);
|
|
}
|
|
|
|
return (0);
|
|
}
|
|
|
|
static void
|
|
cache_lock_vnodes(struct mtx *vlp1, struct mtx *vlp2)
|
|
{
|
|
|
|
MPASS(vlp1 != NULL || vlp2 != NULL);
|
|
MPASS(vlp1 <= vlp2);
|
|
|
|
if (vlp1 != NULL)
|
|
mtx_lock(vlp1);
|
|
if (vlp2 != NULL)
|
|
mtx_lock(vlp2);
|
|
}
|
|
|
|
static void
|
|
cache_unlock_vnodes(struct mtx *vlp1, struct mtx *vlp2)
|
|
{
|
|
|
|
MPASS(vlp1 != NULL || vlp2 != NULL);
|
|
|
|
if (vlp1 != NULL)
|
|
mtx_unlock(vlp1);
|
|
if (vlp2 != NULL)
|
|
mtx_unlock(vlp2);
|
|
}
|
|
|
|
static int
|
|
sysctl_nchstats(SYSCTL_HANDLER_ARGS)
|
|
{
|
|
struct nchstats snap;
|
|
|
|
if (req->oldptr == NULL)
|
|
return (SYSCTL_OUT(req, 0, sizeof(snap)));
|
|
|
|
snap = nchstats;
|
|
snap.ncs_goodhits = counter_u64_fetch(numposhits);
|
|
snap.ncs_neghits = counter_u64_fetch(numneghits);
|
|
snap.ncs_badhits = counter_u64_fetch(numposzaps) +
|
|
counter_u64_fetch(numnegzaps);
|
|
snap.ncs_miss = counter_u64_fetch(nummisszap) +
|
|
counter_u64_fetch(nummiss);
|
|
|
|
return (SYSCTL_OUT(req, &snap, sizeof(snap)));
|
|
}
|
|
SYSCTL_PROC(_vfs_cache, OID_AUTO, nchstats, CTLTYPE_OPAQUE | CTLFLAG_RD |
|
|
CTLFLAG_MPSAFE, 0, 0, sysctl_nchstats, "LU",
|
|
"VFS cache effectiveness statistics");
|
|
|
|
#ifdef DIAGNOSTIC
|
|
/*
|
|
* Grab an atomic snapshot of the name cache hash chain lengths
|
|
*/
|
|
static SYSCTL_NODE(_debug, OID_AUTO, hashstat,
|
|
CTLFLAG_RW | CTLFLAG_MPSAFE, NULL,
|
|
"hash table stats");
|
|
|
|
static int
|
|
sysctl_debug_hashstat_rawnchash(SYSCTL_HANDLER_ARGS)
|
|
{
|
|
struct nchashhead *ncpp;
|
|
struct namecache *ncp;
|
|
int i, error, n_nchash, *cntbuf;
|
|
|
|
retry:
|
|
n_nchash = nchash + 1; /* nchash is max index, not count */
|
|
if (req->oldptr == NULL)
|
|
return SYSCTL_OUT(req, 0, n_nchash * sizeof(int));
|
|
cntbuf = malloc(n_nchash * sizeof(int), M_TEMP, M_ZERO | M_WAITOK);
|
|
cache_lock_all_buckets();
|
|
if (n_nchash != nchash + 1) {
|
|
cache_unlock_all_buckets();
|
|
free(cntbuf, M_TEMP);
|
|
goto retry;
|
|
}
|
|
/* Scan hash tables counting entries */
|
|
for (ncpp = nchashtbl, i = 0; i < n_nchash; ncpp++, i++)
|
|
CK_LIST_FOREACH(ncp, ncpp, nc_hash)
|
|
cntbuf[i]++;
|
|
cache_unlock_all_buckets();
|
|
for (error = 0, i = 0; i < n_nchash; i++)
|
|
if ((error = SYSCTL_OUT(req, &cntbuf[i], sizeof(int))) != 0)
|
|
break;
|
|
free(cntbuf, M_TEMP);
|
|
return (error);
|
|
}
|
|
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));
|
|
|
|
cache_lock_all_buckets();
|
|
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;
|
|
CK_LIST_FOREACH(ncp, ncpp, nc_hash) {
|
|
count++;
|
|
}
|
|
if (count)
|
|
used++;
|
|
if (maxlength < count)
|
|
maxlength = count;
|
|
}
|
|
n_nchash = nchash + 1;
|
|
cache_unlock_all_buckets();
|
|
pct = (used * 100) / (n_nchash / 100);
|
|
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 statistics (number of total/used buckets, maximum chain length, usage percentage)");
|
|
#endif
|
|
|
|
/*
|
|
* Negative entries management
|
|
*
|
|
* A variation of LRU scheme is used. New entries are hashed into one of
|
|
* numneglists cold lists. Entries get promoted to the hot list on first hit.
|
|
*
|
|
* The shrinker will demote hot list head and evict from the cold list in a
|
|
* round-robin manner.
|
|
*/
|
|
static void
|
|
cache_negative_init(struct namecache *ncp)
|
|
{
|
|
struct negstate *negstate;
|
|
|
|
ncp->nc_flag |= NCF_NEGATIVE;
|
|
negstate = NCP2NEGSTATE(ncp);
|
|
negstate->neg_flag = 0;
|
|
}
|
|
|
|
static void
|
|
cache_negative_hit(struct namecache *ncp)
|
|
{
|
|
struct neglist *neglist;
|
|
struct negstate *negstate;
|
|
|
|
negstate = NCP2NEGSTATE(ncp);
|
|
if ((negstate->neg_flag & NEG_HOT) != 0)
|
|
return;
|
|
neglist = NCP2NEGLIST(ncp);
|
|
mtx_lock(&ncneg_hot.nl_lock);
|
|
mtx_lock(&neglist->nl_lock);
|
|
if ((negstate->neg_flag & NEG_HOT) == 0) {
|
|
numhotneg++;
|
|
TAILQ_REMOVE(&neglist->nl_list, ncp, nc_dst);
|
|
TAILQ_INSERT_TAIL(&ncneg_hot.nl_list, ncp, nc_dst);
|
|
negstate->neg_flag |= NEG_HOT;
|
|
}
|
|
mtx_unlock(&neglist->nl_lock);
|
|
mtx_unlock(&ncneg_hot.nl_lock);
|
|
}
|
|
|
|
static void
|
|
cache_negative_insert(struct namecache *ncp)
|
|
{
|
|
struct neglist *neglist;
|
|
|
|
MPASS(ncp->nc_flag & NCF_NEGATIVE);
|
|
cache_assert_bucket_locked(ncp, RA_WLOCKED);
|
|
neglist = NCP2NEGLIST(ncp);
|
|
mtx_lock(&neglist->nl_lock);
|
|
TAILQ_INSERT_TAIL(&neglist->nl_list, ncp, nc_dst);
|
|
mtx_unlock(&neglist->nl_lock);
|
|
atomic_add_rel_long(&numneg, 1);
|
|
}
|
|
|
|
static void
|
|
cache_negative_remove(struct namecache *ncp)
|
|
{
|
|
struct neglist *neglist;
|
|
struct negstate *negstate;
|
|
bool hot_locked = false;
|
|
bool list_locked = false;
|
|
|
|
cache_assert_bucket_locked(ncp, RA_WLOCKED);
|
|
neglist = NCP2NEGLIST(ncp);
|
|
negstate = NCP2NEGSTATE(ncp);
|
|
if ((negstate->neg_flag & NEG_HOT) != 0) {
|
|
hot_locked = true;
|
|
mtx_lock(&ncneg_hot.nl_lock);
|
|
if ((negstate->neg_flag & NEG_HOT) == 0) {
|
|
list_locked = true;
|
|
mtx_lock(&neglist->nl_lock);
|
|
}
|
|
} else {
|
|
list_locked = true;
|
|
mtx_lock(&neglist->nl_lock);
|
|
}
|
|
if ((negstate->neg_flag & NEG_HOT) != 0) {
|
|
mtx_assert(&ncneg_hot.nl_lock, MA_OWNED);
|
|
TAILQ_REMOVE(&ncneg_hot.nl_list, ncp, nc_dst);
|
|
numhotneg--;
|
|
} else {
|
|
mtx_assert(&neglist->nl_lock, MA_OWNED);
|
|
TAILQ_REMOVE(&neglist->nl_list, ncp, nc_dst);
|
|
}
|
|
if (list_locked)
|
|
mtx_unlock(&neglist->nl_lock);
|
|
if (hot_locked)
|
|
mtx_unlock(&ncneg_hot.nl_lock);
|
|
atomic_subtract_rel_long(&numneg, 1);
|
|
}
|
|
|
|
static void
|
|
cache_negative_shrink_select(struct namecache **ncpp,
|
|
struct neglist **neglistpp)
|
|
{
|
|
struct neglist *neglist;
|
|
struct namecache *ncp;
|
|
static u_int cycle;
|
|
u_int i;
|
|
|
|
*ncpp = ncp = NULL;
|
|
|
|
for (i = 0; i < numneglists; i++) {
|
|
neglist = &neglists[(cycle + i) % numneglists];
|
|
if (TAILQ_FIRST(&neglist->nl_list) == NULL)
|
|
continue;
|
|
mtx_lock(&neglist->nl_lock);
|
|
ncp = TAILQ_FIRST(&neglist->nl_list);
|
|
if (ncp != NULL)
|
|
break;
|
|
mtx_unlock(&neglist->nl_lock);
|
|
}
|
|
|
|
*neglistpp = neglist;
|
|
*ncpp = ncp;
|
|
cycle++;
|
|
}
|
|
|
|
static void
|
|
cache_negative_zap_one(void)
|
|
{
|
|
struct namecache *ncp, *ncp2;
|
|
struct neglist *neglist;
|
|
struct negstate *negstate;
|
|
struct mtx *dvlp;
|
|
struct rwlock *blp;
|
|
|
|
if (mtx_owner(&ncneg_shrink_lock) != NULL ||
|
|
!mtx_trylock(&ncneg_shrink_lock)) {
|
|
counter_u64_add(shrinking_skipped, 1);
|
|
return;
|
|
}
|
|
|
|
mtx_lock(&ncneg_hot.nl_lock);
|
|
ncp = TAILQ_FIRST(&ncneg_hot.nl_list);
|
|
if (ncp != NULL) {
|
|
neglist = NCP2NEGLIST(ncp);
|
|
negstate = NCP2NEGSTATE(ncp);
|
|
mtx_lock(&neglist->nl_lock);
|
|
MPASS((negstate->neg_flag & NEG_HOT) != 0);
|
|
TAILQ_REMOVE(&ncneg_hot.nl_list, ncp, nc_dst);
|
|
TAILQ_INSERT_TAIL(&neglist->nl_list, ncp, nc_dst);
|
|
negstate->neg_flag &= ~NEG_HOT;
|
|
numhotneg--;
|
|
mtx_unlock(&neglist->nl_lock);
|
|
}
|
|
mtx_unlock(&ncneg_hot.nl_lock);
|
|
|
|
cache_negative_shrink_select(&ncp, &neglist);
|
|
|
|
mtx_unlock(&ncneg_shrink_lock);
|
|
if (ncp == NULL)
|
|
return;
|
|
|
|
MPASS(ncp->nc_flag & NCF_NEGATIVE);
|
|
dvlp = VP2VNODELOCK(ncp->nc_dvp);
|
|
blp = NCP2BUCKETLOCK(ncp);
|
|
mtx_unlock(&neglist->nl_lock);
|
|
mtx_lock(dvlp);
|
|
rw_wlock(blp);
|
|
/*
|
|
* Enter SMR to safely check the negative list.
|
|
* Even if the found pointer matches, the entry may now be reallocated
|
|
* and used by a different vnode.
|
|
*/
|
|
vfs_smr_enter();
|
|
ncp2 = TAILQ_FIRST(&neglist->nl_list);
|
|
if (ncp != ncp2 || dvlp != VP2VNODELOCK(ncp2->nc_dvp) ||
|
|
blp != NCP2BUCKETLOCK(ncp2)) {
|
|
vfs_smr_exit();
|
|
ncp = NULL;
|
|
} else {
|
|
vfs_smr_exit();
|
|
SDT_PROBE2(vfs, namecache, shrink_negative, done, ncp->nc_dvp,
|
|
ncp->nc_name);
|
|
cache_zap_locked(ncp);
|
|
counter_u64_add(numneg_evicted, 1);
|
|
}
|
|
rw_wunlock(blp);
|
|
mtx_unlock(dvlp);
|
|
cache_free(ncp);
|
|
}
|
|
|
|
/*
|
|
* cache_zap_locked():
|
|
*
|
|
* 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_locked(struct namecache *ncp)
|
|
{
|
|
|
|
if (!(ncp->nc_flag & NCF_NEGATIVE))
|
|
cache_assert_vnode_locked(ncp->nc_vp);
|
|
cache_assert_vnode_locked(ncp->nc_dvp);
|
|
cache_assert_bucket_locked(ncp, RA_WLOCKED);
|
|
|
|
CTR2(KTR_VFS, "cache_zap(%p) vp %p", ncp,
|
|
(ncp->nc_flag & NCF_NEGATIVE) ? NULL : ncp->nc_vp);
|
|
|
|
cache_ncp_invalidate(ncp);
|
|
|
|
CK_LIST_REMOVE(ncp, nc_hash);
|
|
if (!(ncp->nc_flag & NCF_NEGATIVE)) {
|
|
SDT_PROBE3(vfs, namecache, zap, done, ncp->nc_dvp,
|
|
ncp->nc_name, 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 {
|
|
SDT_PROBE2(vfs, namecache, zap_negative, done, ncp->nc_dvp,
|
|
ncp->nc_name);
|
|
cache_negative_remove(ncp);
|
|
}
|
|
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)) {
|
|
ncp->nc_flag |= NCF_DVDROP;
|
|
counter_u64_add(numcachehv, -1);
|
|
}
|
|
}
|
|
atomic_subtract_rel_long(&numcache, 1);
|
|
}
|
|
|
|
static void
|
|
cache_zap_negative_locked_vnode_kl(struct namecache *ncp, struct vnode *vp)
|
|
{
|
|
struct rwlock *blp;
|
|
|
|
MPASS(ncp->nc_dvp == vp);
|
|
MPASS(ncp->nc_flag & NCF_NEGATIVE);
|
|
cache_assert_vnode_locked(vp);
|
|
|
|
blp = NCP2BUCKETLOCK(ncp);
|
|
rw_wlock(blp);
|
|
cache_zap_locked(ncp);
|
|
rw_wunlock(blp);
|
|
}
|
|
|
|
static bool
|
|
cache_zap_locked_vnode_kl2(struct namecache *ncp, struct vnode *vp,
|
|
struct mtx **vlpp)
|
|
{
|
|
struct mtx *pvlp, *vlp1, *vlp2, *to_unlock;
|
|
struct rwlock *blp;
|
|
|
|
MPASS(vp == ncp->nc_dvp || vp == ncp->nc_vp);
|
|
cache_assert_vnode_locked(vp);
|
|
|
|
if (ncp->nc_flag & NCF_NEGATIVE) {
|
|
if (*vlpp != NULL) {
|
|
mtx_unlock(*vlpp);
|
|
*vlpp = NULL;
|
|
}
|
|
cache_zap_negative_locked_vnode_kl(ncp, vp);
|
|
return (true);
|
|
}
|
|
|
|
pvlp = VP2VNODELOCK(vp);
|
|
blp = NCP2BUCKETLOCK(ncp);
|
|
vlp1 = VP2VNODELOCK(ncp->nc_dvp);
|
|
vlp2 = VP2VNODELOCK(ncp->nc_vp);
|
|
|
|
if (*vlpp == vlp1 || *vlpp == vlp2) {
|
|
to_unlock = *vlpp;
|
|
*vlpp = NULL;
|
|
} else {
|
|
if (*vlpp != NULL) {
|
|
mtx_unlock(*vlpp);
|
|
*vlpp = NULL;
|
|
}
|
|
cache_sort_vnodes(&vlp1, &vlp2);
|
|
if (vlp1 == pvlp) {
|
|
mtx_lock(vlp2);
|
|
to_unlock = vlp2;
|
|
} else {
|
|
if (!mtx_trylock(vlp1))
|
|
goto out_relock;
|
|
to_unlock = vlp1;
|
|
}
|
|
}
|
|
rw_wlock(blp);
|
|
cache_zap_locked(ncp);
|
|
rw_wunlock(blp);
|
|
if (to_unlock != NULL)
|
|
mtx_unlock(to_unlock);
|
|
return (true);
|
|
|
|
out_relock:
|
|
mtx_unlock(vlp2);
|
|
mtx_lock(vlp1);
|
|
mtx_lock(vlp2);
|
|
MPASS(*vlpp == NULL);
|
|
*vlpp = vlp1;
|
|
return (false);
|
|
}
|
|
|
|
static int __noinline
|
|
cache_zap_locked_vnode(struct namecache *ncp, struct vnode *vp)
|
|
{
|
|
struct mtx *pvlp, *vlp1, *vlp2, *to_unlock;
|
|
struct rwlock *blp;
|
|
int error = 0;
|
|
|
|
MPASS(vp == ncp->nc_dvp || vp == ncp->nc_vp);
|
|
cache_assert_vnode_locked(vp);
|
|
|
|
pvlp = VP2VNODELOCK(vp);
|
|
if (ncp->nc_flag & NCF_NEGATIVE) {
|
|
cache_zap_negative_locked_vnode_kl(ncp, vp);
|
|
goto out;
|
|
}
|
|
|
|
blp = NCP2BUCKETLOCK(ncp);
|
|
vlp1 = VP2VNODELOCK(ncp->nc_dvp);
|
|
vlp2 = VP2VNODELOCK(ncp->nc_vp);
|
|
cache_sort_vnodes(&vlp1, &vlp2);
|
|
if (vlp1 == pvlp) {
|
|
mtx_lock(vlp2);
|
|
to_unlock = vlp2;
|
|
} else {
|
|
if (!mtx_trylock(vlp1)) {
|
|
error = EAGAIN;
|
|
goto out;
|
|
}
|
|
to_unlock = vlp1;
|
|
}
|
|
rw_wlock(blp);
|
|
cache_zap_locked(ncp);
|
|
rw_wunlock(blp);
|
|
mtx_unlock(to_unlock);
|
|
out:
|
|
mtx_unlock(pvlp);
|
|
return (error);
|
|
}
|
|
|
|
/*
|
|
* If trylocking failed we can get here. We know enough to take all needed locks
|
|
* in the right order and re-lookup the entry.
|
|
*/
|
|
static int
|
|
cache_zap_unlocked_bucket(struct namecache *ncp, struct componentname *cnp,
|
|
struct vnode *dvp, struct mtx *dvlp, struct mtx *vlp, uint32_t hash,
|
|
struct rwlock *blp)
|
|
{
|
|
struct namecache *rncp;
|
|
|
|
cache_assert_bucket_locked(ncp, RA_UNLOCKED);
|
|
|
|
cache_sort_vnodes(&dvlp, &vlp);
|
|
cache_lock_vnodes(dvlp, vlp);
|
|
rw_wlock(blp);
|
|
CK_LIST_FOREACH(rncp, (NCHHASH(hash)), nc_hash) {
|
|
if (rncp == ncp && rncp->nc_dvp == dvp &&
|
|
rncp->nc_nlen == cnp->cn_namelen &&
|
|
!bcmp(rncp->nc_name, cnp->cn_nameptr, rncp->nc_nlen))
|
|
break;
|
|
}
|
|
if (rncp != NULL) {
|
|
cache_zap_locked(rncp);
|
|
rw_wunlock(blp);
|
|
cache_unlock_vnodes(dvlp, vlp);
|
|
counter_u64_add(zap_and_exit_bucket_relock_success, 1);
|
|
return (0);
|
|
}
|
|
|
|
rw_wunlock(blp);
|
|
cache_unlock_vnodes(dvlp, vlp);
|
|
return (EAGAIN);
|
|
}
|
|
|
|
static int __noinline
|
|
cache_zap_wlocked_bucket(struct namecache *ncp, struct componentname *cnp,
|
|
uint32_t hash, struct rwlock *blp)
|
|
{
|
|
struct mtx *dvlp, *vlp;
|
|
struct vnode *dvp;
|
|
|
|
cache_assert_bucket_locked(ncp, RA_WLOCKED);
|
|
|
|
dvlp = VP2VNODELOCK(ncp->nc_dvp);
|
|
vlp = NULL;
|
|
if (!(ncp->nc_flag & NCF_NEGATIVE))
|
|
vlp = VP2VNODELOCK(ncp->nc_vp);
|
|
if (cache_trylock_vnodes(dvlp, vlp) == 0) {
|
|
cache_zap_locked(ncp);
|
|
rw_wunlock(blp);
|
|
cache_unlock_vnodes(dvlp, vlp);
|
|
return (0);
|
|
}
|
|
|
|
dvp = ncp->nc_dvp;
|
|
rw_wunlock(blp);
|
|
return (cache_zap_unlocked_bucket(ncp, cnp, dvp, dvlp, vlp, hash, blp));
|
|
}
|
|
|
|
static int __noinline
|
|
cache_zap_rlocked_bucket(struct namecache *ncp, struct componentname *cnp,
|
|
uint32_t hash, struct rwlock *blp)
|
|
{
|
|
struct mtx *dvlp, *vlp;
|
|
struct vnode *dvp;
|
|
|
|
cache_assert_bucket_locked(ncp, RA_RLOCKED);
|
|
|
|
dvlp = VP2VNODELOCK(ncp->nc_dvp);
|
|
vlp = NULL;
|
|
if (!(ncp->nc_flag & NCF_NEGATIVE))
|
|
vlp = VP2VNODELOCK(ncp->nc_vp);
|
|
if (cache_trylock_vnodes(dvlp, vlp) == 0) {
|
|
rw_runlock(blp);
|
|
rw_wlock(blp);
|
|
cache_zap_locked(ncp);
|
|
rw_wunlock(blp);
|
|
cache_unlock_vnodes(dvlp, vlp);
|
|
return (0);
|
|
}
|
|
|
|
dvp = ncp->nc_dvp;
|
|
rw_runlock(blp);
|
|
return (cache_zap_unlocked_bucket(ncp, cnp, dvp, dvlp, vlp, hash, blp));
|
|
}
|
|
|
|
static int
|
|
cache_zap_wlocked_bucket_kl(struct namecache *ncp, struct rwlock *blp,
|
|
struct mtx **vlpp1, struct mtx **vlpp2)
|
|
{
|
|
struct mtx *dvlp, *vlp;
|
|
|
|
cache_assert_bucket_locked(ncp, RA_WLOCKED);
|
|
|
|
dvlp = VP2VNODELOCK(ncp->nc_dvp);
|
|
vlp = NULL;
|
|
if (!(ncp->nc_flag & NCF_NEGATIVE))
|
|
vlp = VP2VNODELOCK(ncp->nc_vp);
|
|
cache_sort_vnodes(&dvlp, &vlp);
|
|
|
|
if (*vlpp1 == dvlp && *vlpp2 == vlp) {
|
|
cache_zap_locked(ncp);
|
|
cache_unlock_vnodes(dvlp, vlp);
|
|
*vlpp1 = NULL;
|
|
*vlpp2 = NULL;
|
|
return (0);
|
|
}
|
|
|
|
if (*vlpp1 != NULL)
|
|
mtx_unlock(*vlpp1);
|
|
if (*vlpp2 != NULL)
|
|
mtx_unlock(*vlpp2);
|
|
*vlpp1 = NULL;
|
|
*vlpp2 = NULL;
|
|
|
|
if (cache_trylock_vnodes(dvlp, vlp) == 0) {
|
|
cache_zap_locked(ncp);
|
|
cache_unlock_vnodes(dvlp, vlp);
|
|
return (0);
|
|
}
|
|
|
|
rw_wunlock(blp);
|
|
*vlpp1 = dvlp;
|
|
*vlpp2 = vlp;
|
|
if (*vlpp1 != NULL)
|
|
mtx_lock(*vlpp1);
|
|
mtx_lock(*vlpp2);
|
|
rw_wlock(blp);
|
|
return (EAGAIN);
|
|
}
|
|
|
|
static void
|
|
cache_lookup_unlock(struct rwlock *blp, struct mtx *vlp)
|
|
{
|
|
|
|
if (blp != NULL) {
|
|
rw_runlock(blp);
|
|
} else {
|
|
mtx_unlock(vlp);
|
|
}
|
|
}
|
|
|
|
static int __noinline
|
|
cache_lookup_dot(struct vnode *dvp, struct vnode **vpp, struct componentname *cnp,
|
|
struct timespec *tsp, int *ticksp)
|
|
{
|
|
int ltype;
|
|
|
|
*vpp = dvp;
|
|
CTR2(KTR_VFS, "cache_lookup(%p, %s) found via .",
|
|
dvp, cnp->cn_nameptr);
|
|
counter_u64_add(dothits, 1);
|
|
SDT_PROBE3(vfs, namecache, lookup, hit, dvp, ".", *vpp);
|
|
if (tsp != NULL)
|
|
timespecclear(tsp);
|
|
if (ticksp != NULL)
|
|
*ticksp = ticks;
|
|
vrefact(*vpp);
|
|
/*
|
|
* 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 (VN_IS_DOOMED((*vpp))) {
|
|
/* forced unmount */
|
|
vrele(*vpp);
|
|
*vpp = NULL;
|
|
return (ENOENT);
|
|
}
|
|
} else
|
|
vn_lock(*vpp, LK_DOWNGRADE | LK_RETRY);
|
|
}
|
|
return (-1);
|
|
}
|
|
|
|
static __noinline int
|
|
cache_lookup_nomakeentry(struct vnode *dvp, struct vnode **vpp,
|
|
struct componentname *cnp, struct timespec *tsp, int *ticksp)
|
|
{
|
|
struct namecache *ncp;
|
|
struct rwlock *blp;
|
|
struct mtx *dvlp, *dvlp2;
|
|
uint32_t hash;
|
|
int error;
|
|
|
|
if (cnp->cn_namelen == 2 &&
|
|
cnp->cn_nameptr[0] == '.' && cnp->cn_nameptr[1] == '.') {
|
|
counter_u64_add(dotdothits, 1);
|
|
dvlp = VP2VNODELOCK(dvp);
|
|
dvlp2 = NULL;
|
|
mtx_lock(dvlp);
|
|
retry_dotdot:
|
|
ncp = dvp->v_cache_dd;
|
|
if (ncp == NULL) {
|
|
SDT_PROBE3(vfs, namecache, lookup, miss, dvp,
|
|
"..", NULL);
|
|
mtx_unlock(dvlp);
|
|
if (dvlp2 != NULL)
|
|
mtx_unlock(dvlp2);
|
|
return (0);
|
|
}
|
|
if ((ncp->nc_flag & NCF_ISDOTDOT) != 0) {
|
|
if (ncp->nc_dvp != dvp)
|
|
panic("dvp %p v_cache_dd %p\n", dvp, ncp);
|
|
if (!cache_zap_locked_vnode_kl2(ncp,
|
|
dvp, &dvlp2))
|
|
goto retry_dotdot;
|
|
MPASS(dvp->v_cache_dd == NULL);
|
|
mtx_unlock(dvlp);
|
|
if (dvlp2 != NULL)
|
|
mtx_unlock(dvlp2);
|
|
cache_free(ncp);
|
|
} else {
|
|
dvp->v_cache_dd = NULL;
|
|
mtx_unlock(dvlp);
|
|
if (dvlp2 != NULL)
|
|
mtx_unlock(dvlp2);
|
|
}
|
|
return (0);
|
|
}
|
|
|
|
hash = cache_get_hash(cnp->cn_nameptr, cnp->cn_namelen, dvp);
|
|
blp = HASH2BUCKETLOCK(hash);
|
|
retry:
|
|
if (CK_LIST_EMPTY(NCHHASH(hash)))
|
|
goto out_no_entry;
|
|
|
|
rw_wlock(blp);
|
|
|
|
CK_LIST_FOREACH(ncp, (NCHHASH(hash)), nc_hash) {
|
|
counter_u64_add(numchecks, 1);
|
|
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) {
|
|
rw_wunlock(blp);
|
|
goto out_no_entry;
|
|
}
|
|
|
|
error = cache_zap_wlocked_bucket(ncp, cnp, hash, blp);
|
|
if (__predict_false(error != 0)) {
|
|
zap_and_exit_bucket_fail++;
|
|
cache_maybe_yield();
|
|
goto retry;
|
|
}
|
|
counter_u64_add(numposzaps, 1);
|
|
cache_free(ncp);
|
|
return (0);
|
|
out_no_entry:
|
|
SDT_PROBE3(vfs, namecache, lookup, miss, dvp, cnp->cn_nameptr, NULL);
|
|
counter_u64_add(nummisszap, 1);
|
|
return (0);
|
|
}
|
|
|
|
/**
|
|
* Lookup a name in the name cache
|
|
*
|
|
* # Arguments
|
|
*
|
|
* - dvp: Parent directory in which to search.
|
|
* - vpp: Return argument. Will contain desired vnode on cache hit.
|
|
* - cnp: Parameters of the name search. The most interesting bits of
|
|
* the cn_flags field have the following meanings:
|
|
* - MAKEENTRY: If clear, free an entry from the cache rather than look
|
|
* it up.
|
|
* - ISDOTDOT: Must be set if and only if cn_nameptr == ".."
|
|
* - tsp: Return storage for cache timestamp. On a successful (positive
|
|
* or negative) lookup, tsp will be filled with any timespec that
|
|
* was stored when this cache entry was created. However, it will
|
|
* be clear for "." entries.
|
|
* - ticks: Return storage for alternate cache timestamp. On a successful
|
|
* (positive or negative) lookup, it will contain the ticks value
|
|
* that was current when the cache entry was created, unless cnp
|
|
* was ".".
|
|
*
|
|
* # Returns
|
|
*
|
|
* - -1: A positive cache hit. vpp will contain the desired vnode.
|
|
* - ENOENT: A negative cache hit, or dvp was recycled out from under us due
|
|
* to a forced unmount. vpp will not be modified. If the entry
|
|
* is a whiteout, then the ISWHITEOUT flag will be set in
|
|
* cnp->cn_flags.
|
|
* - 0: A cache miss. vpp will not be modified.
|
|
*
|
|
* # Locking
|
|
*
|
|
* On a cache hit, vpp will be returned locked and ref'd. If we're looking up
|
|
* .., dvp is unlocked. If we're looking up . an extra ref is taken, but the
|
|
* lock is not recursively acquired.
|
|
*/
|
|
int
|
|
cache_lookup(struct vnode *dvp, struct vnode **vpp, struct componentname *cnp,
|
|
struct timespec *tsp, int *ticksp)
|
|
{
|
|
struct namecache_ts *ncp_ts;
|
|
struct namecache *ncp;
|
|
struct negstate *negstate;
|
|
struct rwlock *blp;
|
|
struct mtx *dvlp;
|
|
uint32_t hash;
|
|
enum vgetstate vs;
|
|
int error, ltype;
|
|
bool try_smr, doing_smr, whiteout;
|
|
|
|
#ifdef DEBUG_CACHE
|
|
if (__predict_false(!doingcache)) {
|
|
cnp->cn_flags &= ~MAKEENTRY;
|
|
return (0);
|
|
}
|
|
#endif
|
|
|
|
if (__predict_false(cnp->cn_namelen == 1 && cnp->cn_nameptr[0] == '.'))
|
|
return (cache_lookup_dot(dvp, vpp, cnp, tsp, ticksp));
|
|
|
|
if ((cnp->cn_flags & MAKEENTRY) == 0)
|
|
return (cache_lookup_nomakeentry(dvp, vpp, cnp, tsp, ticksp));
|
|
|
|
try_smr = true;
|
|
if (cnp->cn_nameiop == CREATE)
|
|
try_smr = false;
|
|
retry:
|
|
doing_smr = false;
|
|
blp = NULL;
|
|
dvlp = NULL;
|
|
error = 0;
|
|
if (cnp->cn_namelen == 2 &&
|
|
cnp->cn_nameptr[0] == '.' && cnp->cn_nameptr[1] == '.') {
|
|
counter_u64_add(dotdothits, 1);
|
|
dvlp = VP2VNODELOCK(dvp);
|
|
mtx_lock(dvlp);
|
|
ncp = dvp->v_cache_dd;
|
|
if (ncp == NULL) {
|
|
SDT_PROBE3(vfs, namecache, lookup, miss, dvp,
|
|
"..", NULL);
|
|
mtx_unlock(dvlp);
|
|
return (0);
|
|
}
|
|
if ((ncp->nc_flag & NCF_ISDOTDOT) != 0) {
|
|
if (ncp->nc_flag & NCF_NEGATIVE)
|
|
*vpp = NULL;
|
|
else
|
|
*vpp = ncp->nc_vp;
|
|
} else
|
|
*vpp = ncp->nc_dvp;
|
|
/* Return failure if negative entry was found. */
|
|
if (*vpp == NULL)
|
|
goto negative_success;
|
|
CTR3(KTR_VFS, "cache_lookup(%p, %s) found %p via ..",
|
|
dvp, cnp->cn_nameptr, *vpp);
|
|
SDT_PROBE3(vfs, namecache, lookup, hit, dvp, "..",
|
|
*vpp);
|
|
cache_out_ts(ncp, tsp, ticksp);
|
|
if ((ncp->nc_flag & (NCF_ISDOTDOT | NCF_DTS)) ==
|
|
NCF_DTS && tsp != NULL) {
|
|
ncp_ts = __containerof(ncp, struct namecache_ts, nc_nc);
|
|
*tsp = ncp_ts->nc_dotdottime;
|
|
}
|
|
goto success;
|
|
}
|
|
|
|
hash = cache_get_hash(cnp->cn_nameptr, cnp->cn_namelen, dvp);
|
|
retry_hashed:
|
|
if (try_smr) {
|
|
vfs_smr_enter();
|
|
doing_smr = true;
|
|
try_smr = false;
|
|
} else {
|
|
blp = HASH2BUCKETLOCK(hash);
|
|
rw_rlock(blp);
|
|
}
|
|
|
|
CK_LIST_FOREACH(ncp, (NCHHASH(hash)), nc_hash) {
|
|
counter_u64_add(numchecks, 1);
|
|
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 (__predict_false(ncp == NULL)) {
|
|
if (doing_smr)
|
|
vfs_smr_exit();
|
|
else
|
|
rw_runlock(blp);
|
|
SDT_PROBE3(vfs, namecache, lookup, miss, dvp, cnp->cn_nameptr,
|
|
NULL);
|
|
counter_u64_add(nummiss, 1);
|
|
return (0);
|
|
}
|
|
|
|
if (ncp->nc_flag & NCF_NEGATIVE)
|
|
goto negative_success;
|
|
|
|
/* We found a "positive" match, return the vnode */
|
|
counter_u64_add(numposhits, 1);
|
|
*vpp = ncp->nc_vp;
|
|
CTR4(KTR_VFS, "cache_lookup(%p, %s) found %p via ncp %p",
|
|
dvp, cnp->cn_nameptr, *vpp, ncp);
|
|
SDT_PROBE3(vfs, namecache, lookup, hit, dvp, ncp->nc_name,
|
|
*vpp);
|
|
cache_out_ts(ncp, tsp, ticksp);
|
|
success:
|
|
/*
|
|
* On success we return a locked and ref'd vnode as per the lookup
|
|
* protocol.
|
|
*/
|
|
MPASS(dvp != *vpp);
|
|
ltype = 0; /* silence gcc warning */
|
|
if (cnp->cn_flags & ISDOTDOT) {
|
|
ltype = VOP_ISLOCKED(dvp);
|
|
VOP_UNLOCK(dvp);
|
|
}
|
|
if (doing_smr) {
|
|
if (cache_ncp_invalid(ncp)) {
|
|
vfs_smr_exit();
|
|
*vpp = NULL;
|
|
goto retry;
|
|
}
|
|
vs = vget_prep_smr(*vpp);
|
|
vfs_smr_exit();
|
|
if (vs == VGET_NONE) {
|
|
*vpp = NULL;
|
|
goto retry;
|
|
}
|
|
} else {
|
|
vs = vget_prep(*vpp);
|
|
cache_lookup_unlock(blp, dvlp);
|
|
}
|
|
error = vget_finish(*vpp, cnp->cn_lkflags, vs);
|
|
if (cnp->cn_flags & ISDOTDOT) {
|
|
vn_lock(dvp, ltype | LK_RETRY);
|
|
if (VN_IS_DOOMED(dvp)) {
|
|
if (error == 0)
|
|
vput(*vpp);
|
|
*vpp = NULL;
|
|
return (ENOENT);
|
|
}
|
|
}
|
|
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);
|
|
|
|
negative_success:
|
|
/* We found a negative match, and want to create it, so purge */
|
|
if (cnp->cn_nameiop == CREATE) {
|
|
MPASS(!doing_smr);
|
|
counter_u64_add(numnegzaps, 1);
|
|
goto zap_and_exit;
|
|
}
|
|
|
|
SDT_PROBE2(vfs, namecache, lookup, hit__negative, dvp, ncp->nc_name);
|
|
cache_out_ts(ncp, tsp, ticksp);
|
|
counter_u64_add(numneghits, 1);
|
|
whiteout = (ncp->nc_flag & NCF_WHITE);
|
|
|
|
if (doing_smr) {
|
|
/*
|
|
* We need to take locks to promote an entry.
|
|
*/
|
|
negstate = NCP2NEGSTATE(ncp);
|
|
if ((negstate->neg_flag & NEG_HOT) == 0 ||
|
|
cache_ncp_invalid(ncp)) {
|
|
vfs_smr_exit();
|
|
doing_smr = false;
|
|
goto retry_hashed;
|
|
}
|
|
vfs_smr_exit();
|
|
} else {
|
|
cache_negative_hit(ncp);
|
|
cache_lookup_unlock(blp, dvlp);
|
|
}
|
|
if (whiteout)
|
|
cnp->cn_flags |= ISWHITEOUT;
|
|
return (ENOENT);
|
|
|
|
zap_and_exit:
|
|
MPASS(!doing_smr);
|
|
if (blp != NULL)
|
|
error = cache_zap_rlocked_bucket(ncp, cnp, hash, blp);
|
|
else
|
|
error = cache_zap_locked_vnode(ncp, dvp);
|
|
if (__predict_false(error != 0)) {
|
|
zap_and_exit_bucket_fail2++;
|
|
cache_maybe_yield();
|
|
goto retry;
|
|
}
|
|
cache_free(ncp);
|
|
return (0);
|
|
}
|
|
|
|
struct celockstate {
|
|
struct mtx *vlp[3];
|
|
struct rwlock *blp[2];
|
|
};
|
|
CTASSERT((nitems(((struct celockstate *)0)->vlp) == 3));
|
|
CTASSERT((nitems(((struct celockstate *)0)->blp) == 2));
|
|
|
|
static inline void
|
|
cache_celockstate_init(struct celockstate *cel)
|
|
{
|
|
|
|
bzero(cel, sizeof(*cel));
|
|
}
|
|
|
|
static void
|
|
cache_lock_vnodes_cel(struct celockstate *cel, struct vnode *vp,
|
|
struct vnode *dvp)
|
|
{
|
|
struct mtx *vlp1, *vlp2;
|
|
|
|
MPASS(cel->vlp[0] == NULL);
|
|
MPASS(cel->vlp[1] == NULL);
|
|
MPASS(cel->vlp[2] == NULL);
|
|
|
|
MPASS(vp != NULL || dvp != NULL);
|
|
|
|
vlp1 = VP2VNODELOCK(vp);
|
|
vlp2 = VP2VNODELOCK(dvp);
|
|
cache_sort_vnodes(&vlp1, &vlp2);
|
|
|
|
if (vlp1 != NULL) {
|
|
mtx_lock(vlp1);
|
|
cel->vlp[0] = vlp1;
|
|
}
|
|
mtx_lock(vlp2);
|
|
cel->vlp[1] = vlp2;
|
|
}
|
|
|
|
static void
|
|
cache_unlock_vnodes_cel(struct celockstate *cel)
|
|
{
|
|
|
|
MPASS(cel->vlp[0] != NULL || cel->vlp[1] != NULL);
|
|
|
|
if (cel->vlp[0] != NULL)
|
|
mtx_unlock(cel->vlp[0]);
|
|
if (cel->vlp[1] != NULL)
|
|
mtx_unlock(cel->vlp[1]);
|
|
if (cel->vlp[2] != NULL)
|
|
mtx_unlock(cel->vlp[2]);
|
|
}
|
|
|
|
static bool
|
|
cache_lock_vnodes_cel_3(struct celockstate *cel, struct vnode *vp)
|
|
{
|
|
struct mtx *vlp;
|
|
bool ret;
|
|
|
|
cache_assert_vlp_locked(cel->vlp[0]);
|
|
cache_assert_vlp_locked(cel->vlp[1]);
|
|
MPASS(cel->vlp[2] == NULL);
|
|
|
|
MPASS(vp != NULL);
|
|
vlp = VP2VNODELOCK(vp);
|
|
|
|
ret = true;
|
|
if (vlp >= cel->vlp[1]) {
|
|
mtx_lock(vlp);
|
|
} else {
|
|
if (mtx_trylock(vlp))
|
|
goto out;
|
|
cache_lock_vnodes_cel_3_failures++;
|
|
cache_unlock_vnodes_cel(cel);
|
|
if (vlp < cel->vlp[0]) {
|
|
mtx_lock(vlp);
|
|
mtx_lock(cel->vlp[0]);
|
|
mtx_lock(cel->vlp[1]);
|
|
} else {
|
|
if (cel->vlp[0] != NULL)
|
|
mtx_lock(cel->vlp[0]);
|
|
mtx_lock(vlp);
|
|
mtx_lock(cel->vlp[1]);
|
|
}
|
|
ret = false;
|
|
}
|
|
out:
|
|
cel->vlp[2] = vlp;
|
|
return (ret);
|
|
}
|
|
|
|
static void
|
|
cache_lock_buckets_cel(struct celockstate *cel, struct rwlock *blp1,
|
|
struct rwlock *blp2)
|
|
{
|
|
|
|
MPASS(cel->blp[0] == NULL);
|
|
MPASS(cel->blp[1] == NULL);
|
|
|
|
cache_sort_vnodes(&blp1, &blp2);
|
|
|
|
if (blp1 != NULL) {
|
|
rw_wlock(blp1);
|
|
cel->blp[0] = blp1;
|
|
}
|
|
rw_wlock(blp2);
|
|
cel->blp[1] = blp2;
|
|
}
|
|
|
|
static void
|
|
cache_unlock_buckets_cel(struct celockstate *cel)
|
|
{
|
|
|
|
if (cel->blp[0] != NULL)
|
|
rw_wunlock(cel->blp[0]);
|
|
rw_wunlock(cel->blp[1]);
|
|
}
|
|
|
|
/*
|
|
* Lock part of the cache affected by the insertion.
|
|
*
|
|
* This means vnodelocks for dvp, vp and the relevant bucketlock.
|
|
* However, insertion can result in removal of an old entry. In this
|
|
* case we have an additional vnode and bucketlock pair to lock. If the
|
|
* entry is negative, ncelock is locked instead of the vnode.
|
|
*
|
|
* That is, in the worst case we have to lock 3 vnodes and 2 bucketlocks, while
|
|
* preserving the locking order (smaller address first).
|
|
*/
|
|
static void
|
|
cache_enter_lock(struct celockstate *cel, struct vnode *dvp, struct vnode *vp,
|
|
uint32_t hash)
|
|
{
|
|
struct namecache *ncp;
|
|
struct rwlock *blps[2];
|
|
|
|
blps[0] = HASH2BUCKETLOCK(hash);
|
|
for (;;) {
|
|
blps[1] = NULL;
|
|
cache_lock_vnodes_cel(cel, dvp, vp);
|
|
if (vp == NULL || vp->v_type != VDIR)
|
|
break;
|
|
ncp = vp->v_cache_dd;
|
|
if (ncp == NULL)
|
|
break;
|
|
if ((ncp->nc_flag & NCF_ISDOTDOT) == 0)
|
|
break;
|
|
MPASS(ncp->nc_dvp == vp);
|
|
blps[1] = NCP2BUCKETLOCK(ncp);
|
|
if (ncp->nc_flag & NCF_NEGATIVE)
|
|
break;
|
|
if (cache_lock_vnodes_cel_3(cel, ncp->nc_vp))
|
|
break;
|
|
/*
|
|
* All vnodes got re-locked. Re-validate the state and if
|
|
* nothing changed we are done. Otherwise restart.
|
|
*/
|
|
if (ncp == vp->v_cache_dd &&
|
|
(ncp->nc_flag & NCF_ISDOTDOT) != 0 &&
|
|
blps[1] == NCP2BUCKETLOCK(ncp) &&
|
|
VP2VNODELOCK(ncp->nc_vp) == cel->vlp[2])
|
|
break;
|
|
cache_unlock_vnodes_cel(cel);
|
|
cel->vlp[0] = NULL;
|
|
cel->vlp[1] = NULL;
|
|
cel->vlp[2] = NULL;
|
|
}
|
|
cache_lock_buckets_cel(cel, blps[0], blps[1]);
|
|
}
|
|
|
|
static void
|
|
cache_enter_lock_dd(struct celockstate *cel, struct vnode *dvp, struct vnode *vp,
|
|
uint32_t hash)
|
|
{
|
|
struct namecache *ncp;
|
|
struct rwlock *blps[2];
|
|
|
|
blps[0] = HASH2BUCKETLOCK(hash);
|
|
for (;;) {
|
|
blps[1] = NULL;
|
|
cache_lock_vnodes_cel(cel, dvp, vp);
|
|
ncp = dvp->v_cache_dd;
|
|
if (ncp == NULL)
|
|
break;
|
|
if ((ncp->nc_flag & NCF_ISDOTDOT) == 0)
|
|
break;
|
|
MPASS(ncp->nc_dvp == dvp);
|
|
blps[1] = NCP2BUCKETLOCK(ncp);
|
|
if (ncp->nc_flag & NCF_NEGATIVE)
|
|
break;
|
|
if (cache_lock_vnodes_cel_3(cel, ncp->nc_vp))
|
|
break;
|
|
if (ncp == dvp->v_cache_dd &&
|
|
(ncp->nc_flag & NCF_ISDOTDOT) != 0 &&
|
|
blps[1] == NCP2BUCKETLOCK(ncp) &&
|
|
VP2VNODELOCK(ncp->nc_vp) == cel->vlp[2])
|
|
break;
|
|
cache_unlock_vnodes_cel(cel);
|
|
cel->vlp[0] = NULL;
|
|
cel->vlp[1] = NULL;
|
|
cel->vlp[2] = NULL;
|
|
}
|
|
cache_lock_buckets_cel(cel, blps[0], blps[1]);
|
|
}
|
|
|
|
static void
|
|
cache_enter_unlock(struct celockstate *cel)
|
|
{
|
|
|
|
cache_unlock_buckets_cel(cel);
|
|
cache_unlock_vnodes_cel(cel);
|
|
}
|
|
|
|
static void __noinline
|
|
cache_enter_dotdot_prep(struct vnode *dvp, struct vnode *vp,
|
|
struct componentname *cnp)
|
|
{
|
|
struct celockstate cel;
|
|
struct namecache *ncp;
|
|
uint32_t hash;
|
|
int len;
|
|
|
|
if (dvp->v_cache_dd == NULL)
|
|
return;
|
|
len = cnp->cn_namelen;
|
|
cache_celockstate_init(&cel);
|
|
hash = cache_get_hash(cnp->cn_nameptr, len, dvp);
|
|
cache_enter_lock_dd(&cel, dvp, vp, hash);
|
|
ncp = dvp->v_cache_dd;
|
|
if (ncp != NULL && (ncp->nc_flag & NCF_ISDOTDOT)) {
|
|
KASSERT(ncp->nc_dvp == dvp, ("wrong isdotdot parent"));
|
|
cache_zap_locked(ncp);
|
|
} else {
|
|
ncp = NULL;
|
|
}
|
|
dvp->v_cache_dd = NULL;
|
|
cache_enter_unlock(&cel);
|
|
cache_free(ncp);
|
|
}
|
|
|
|
/*
|
|
* Add an entry to the cache.
|
|
*/
|
|
void
|
|
cache_enter_time(struct vnode *dvp, struct vnode *vp, struct componentname *cnp,
|
|
struct timespec *tsp, struct timespec *dtsp)
|
|
{
|
|
struct celockstate cel;
|
|
struct namecache *ncp, *n2, *ndd;
|
|
struct namecache_ts *ncp_ts, *n2_ts;
|
|
struct nchashhead *ncpp;
|
|
uint32_t hash;
|
|
int flag;
|
|
int len;
|
|
u_long lnumcache;
|
|
|
|
CTR3(KTR_VFS, "cache_enter(%p, %p, %s)", dvp, vp, cnp->cn_nameptr);
|
|
VNASSERT(vp == NULL || !VN_IS_DOOMED(vp), vp,
|
|
("cache_enter: Adding a doomed vnode"));
|
|
VNASSERT(dvp == NULL || !VN_IS_DOOMED(dvp), dvp,
|
|
("cache_enter: Doomed vnode used as src"));
|
|
|
|
#ifdef DEBUG_CACHE
|
|
if (__predict_false(!doingcache))
|
|
return;
|
|
#endif
|
|
|
|
flag = 0;
|
|
if (__predict_false(cnp->cn_nameptr[0] == '.')) {
|
|
if (cnp->cn_namelen == 1)
|
|
return;
|
|
if (cnp->cn_namelen == 2 && cnp->cn_nameptr[1] == '.') {
|
|
cache_enter_dotdot_prep(dvp, vp, cnp);
|
|
flag = NCF_ISDOTDOT;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Avoid blowout in namecache entries.
|
|
*/
|
|
lnumcache = atomic_fetchadd_long(&numcache, 1) + 1;
|
|
if (__predict_false(lnumcache >= ncsize)) {
|
|
atomic_add_long(&numcache, -1);
|
|
counter_u64_add(numdrops, 1);
|
|
return;
|
|
}
|
|
|
|
cache_celockstate_init(&cel);
|
|
ndd = NULL;
|
|
ncp_ts = NULL;
|
|
|
|
/*
|
|
* 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, tsp != NULL);
|
|
ncp->nc_flag = flag;
|
|
ncp->nc_vp = vp;
|
|
if (vp == NULL)
|
|
cache_negative_init(ncp);
|
|
ncp->nc_dvp = dvp;
|
|
if (tsp != NULL) {
|
|
ncp_ts = __containerof(ncp, struct namecache_ts, nc_nc);
|
|
ncp_ts->nc_time = *tsp;
|
|
ncp_ts->nc_ticks = ticks;
|
|
ncp_ts->nc_nc.nc_flag |= NCF_TS;
|
|
if (dtsp != NULL) {
|
|
ncp_ts->nc_dotdottime = *dtsp;
|
|
ncp_ts->nc_nc.nc_flag |= NCF_DTS;
|
|
}
|
|
}
|
|
len = ncp->nc_nlen = cnp->cn_namelen;
|
|
hash = cache_get_hash(cnp->cn_nameptr, len, dvp);
|
|
strlcpy(ncp->nc_name, cnp->cn_nameptr, len + 1);
|
|
cache_enter_lock(&cel, dvp, vp, hash);
|
|
|
|
/*
|
|
* 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);
|
|
CK_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)) {
|
|
if (tsp != NULL) {
|
|
KASSERT((n2->nc_flag & NCF_TS) != 0,
|
|
("no NCF_TS"));
|
|
n2_ts = __containerof(n2, struct namecache_ts, nc_nc);
|
|
n2_ts->nc_time = ncp_ts->nc_time;
|
|
n2_ts->nc_ticks = ncp_ts->nc_ticks;
|
|
if (dtsp != NULL) {
|
|
n2_ts->nc_dotdottime = ncp_ts->nc_dotdottime;
|
|
n2_ts->nc_nc.nc_flag |= NCF_DTS;
|
|
}
|
|
}
|
|
goto out_unlock_free;
|
|
}
|
|
}
|
|
|
|
if (flag == NCF_ISDOTDOT) {
|
|
/*
|
|
* See if we are trying to add .. entry, but some other lookup
|
|
* has populated v_cache_dd pointer already.
|
|
*/
|
|
if (dvp->v_cache_dd != NULL)
|
|
goto out_unlock_free;
|
|
KASSERT(vp == NULL || vp->v_type == VDIR,
|
|
("wrong vnode type %p", vp));
|
|
dvp->v_cache_dd = ncp;
|
|
}
|
|
|
|
if (vp != NULL) {
|
|
if (vp->v_type == VDIR) {
|
|
if (flag != NCF_ISDOTDOT) {
|
|
/*
|
|
* For this case, the cache entry maps both the
|
|
* directory name in it and the name ".." for the
|
|
* directory's parent.
|
|
*/
|
|
if ((ndd = vp->v_cache_dd) != NULL) {
|
|
if ((ndd->nc_flag & NCF_ISDOTDOT) != 0)
|
|
cache_zap_locked(ndd);
|
|
else
|
|
ndd = NULL;
|
|
}
|
|
vp->v_cache_dd = ncp;
|
|
}
|
|
} else {
|
|
vp->v_cache_dd = NULL;
|
|
}
|
|
}
|
|
|
|
if (flag != NCF_ISDOTDOT) {
|
|
if (LIST_EMPTY(&dvp->v_cache_src)) {
|
|
vhold(dvp);
|
|
counter_u64_add(numcachehv, 1);
|
|
}
|
|
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 != NULL) {
|
|
TAILQ_INSERT_HEAD(&vp->v_cache_dst, ncp, nc_dst);
|
|
SDT_PROBE3(vfs, namecache, enter, done, dvp, ncp->nc_name,
|
|
vp);
|
|
} else {
|
|
if (cnp->cn_flags & ISWHITEOUT)
|
|
ncp->nc_flag |= NCF_WHITE;
|
|
cache_negative_insert(ncp);
|
|
SDT_PROBE2(vfs, namecache, enter_negative, done, dvp,
|
|
ncp->nc_name);
|
|
}
|
|
|
|
atomic_thread_fence_rel();
|
|
/*
|
|
* Insert the new namecache entry into the appropriate chain
|
|
* within the cache entries table.
|
|
*/
|
|
CK_LIST_INSERT_HEAD(ncpp, ncp, nc_hash);
|
|
|
|
cache_enter_unlock(&cel);
|
|
if (numneg * ncnegfactor > lnumcache)
|
|
cache_negative_zap_one();
|
|
cache_free(ndd);
|
|
return;
|
|
out_unlock_free:
|
|
cache_enter_unlock(&cel);
|
|
cache_free(ncp);
|
|
return;
|
|
}
|
|
|
|
static u_int
|
|
cache_roundup_2(u_int val)
|
|
{
|
|
u_int res;
|
|
|
|
for (res = 1; res <= val; res <<= 1)
|
|
continue;
|
|
|
|
return (res);
|
|
}
|
|
|
|
/*
|
|
* Name cache initialization, from vfs_init() when we are booting
|
|
*/
|
|
static void
|
|
nchinit(void *dummy __unused)
|
|
{
|
|
u_int i;
|
|
|
|
cache_zone_small = uma_zcreate("S VFS Cache",
|
|
sizeof(struct namecache) + CACHE_PATH_CUTOFF + 1,
|
|
NULL, NULL, NULL, NULL, UMA_ALIGNOF(struct namecache),
|
|
UMA_ZONE_ZINIT);
|
|
cache_zone_small_ts = uma_zcreate("STS VFS Cache",
|
|
sizeof(struct namecache_ts) + CACHE_PATH_CUTOFF + 1,
|
|
NULL, NULL, NULL, NULL, UMA_ALIGNOF(struct namecache_ts),
|
|
UMA_ZONE_ZINIT);
|
|
cache_zone_large = uma_zcreate("L VFS Cache",
|
|
sizeof(struct namecache) + NAME_MAX + 1,
|
|
NULL, NULL, NULL, NULL, UMA_ALIGNOF(struct namecache),
|
|
UMA_ZONE_ZINIT);
|
|
cache_zone_large_ts = uma_zcreate("LTS VFS Cache",
|
|
sizeof(struct namecache_ts) + NAME_MAX + 1,
|
|
NULL, NULL, NULL, NULL, UMA_ALIGNOF(struct namecache_ts),
|
|
UMA_ZONE_ZINIT);
|
|
|
|
VFS_SMR_ZONE_SET(cache_zone_small);
|
|
VFS_SMR_ZONE_SET(cache_zone_small_ts);
|
|
VFS_SMR_ZONE_SET(cache_zone_large);
|
|
VFS_SMR_ZONE_SET(cache_zone_large_ts);
|
|
|
|
ncsize = desiredvnodes * ncsizefactor;
|
|
nchashtbl = hashinit(desiredvnodes * 2, M_VFSCACHE, &nchash);
|
|
ncbuckethash = cache_roundup_2(mp_ncpus * mp_ncpus) - 1;
|
|
if (ncbuckethash < 7) /* arbitrarily chosen to avoid having one lock */
|
|
ncbuckethash = 7;
|
|
if (ncbuckethash > nchash)
|
|
ncbuckethash = nchash;
|
|
bucketlocks = malloc(sizeof(*bucketlocks) * numbucketlocks, M_VFSCACHE,
|
|
M_WAITOK | M_ZERO);
|
|
for (i = 0; i < numbucketlocks; i++)
|
|
rw_init_flags(&bucketlocks[i], "ncbuc", RW_DUPOK | RW_RECURSE);
|
|
ncvnodehash = ncbuckethash;
|
|
vnodelocks = malloc(sizeof(*vnodelocks) * numvnodelocks, M_VFSCACHE,
|
|
M_WAITOK | M_ZERO);
|
|
for (i = 0; i < numvnodelocks; i++)
|
|
mtx_init(&vnodelocks[i], "ncvn", NULL, MTX_DUPOK | MTX_RECURSE);
|
|
ncpurgeminvnodes = numbucketlocks * 2;
|
|
|
|
ncneghash = 3;
|
|
neglists = malloc(sizeof(*neglists) * numneglists, M_VFSCACHE,
|
|
M_WAITOK | M_ZERO);
|
|
for (i = 0; i < numneglists; i++) {
|
|
mtx_init(&neglists[i].nl_lock, "ncnegl", NULL, MTX_DEF);
|
|
TAILQ_INIT(&neglists[i].nl_list);
|
|
}
|
|
mtx_init(&ncneg_hot.nl_lock, "ncneglh", NULL, MTX_DEF);
|
|
TAILQ_INIT(&ncneg_hot.nl_list);
|
|
|
|
mtx_init(&ncneg_shrink_lock, "ncnegs", NULL, MTX_DEF);
|
|
}
|
|
SYSINIT(vfs, SI_SUB_VFS, SI_ORDER_SECOND, nchinit, NULL);
|
|
|
|
void
|
|
cache_changesize(u_long newmaxvnodes)
|
|
{
|
|
struct nchashhead *new_nchashtbl, *old_nchashtbl;
|
|
u_long new_nchash, old_nchash;
|
|
struct namecache *ncp;
|
|
uint32_t hash;
|
|
u_long newncsize;
|
|
int i;
|
|
|
|
newncsize = newmaxvnodes * ncsizefactor;
|
|
newmaxvnodes = cache_roundup_2(newmaxvnodes * 2);
|
|
if (newmaxvnodes < numbucketlocks)
|
|
newmaxvnodes = numbucketlocks;
|
|
|
|
new_nchashtbl = hashinit(newmaxvnodes, M_VFSCACHE, &new_nchash);
|
|
/* If same hash table size, nothing to do */
|
|
if (nchash == new_nchash) {
|
|
free(new_nchashtbl, M_VFSCACHE);
|
|
return;
|
|
}
|
|
/*
|
|
* Move everything from the old hash table to the new table.
|
|
* None of the namecache entries in the table can be removed
|
|
* because to do so, they have to be removed from the hash table.
|
|
*/
|
|
cache_lock_all_vnodes();
|
|
cache_lock_all_buckets();
|
|
old_nchashtbl = nchashtbl;
|
|
old_nchash = nchash;
|
|
nchashtbl = new_nchashtbl;
|
|
nchash = new_nchash;
|
|
for (i = 0; i <= old_nchash; i++) {
|
|
while ((ncp = CK_LIST_FIRST(&old_nchashtbl[i])) != NULL) {
|
|
hash = cache_get_hash(ncp->nc_name, ncp->nc_nlen,
|
|
ncp->nc_dvp);
|
|
CK_LIST_REMOVE(ncp, nc_hash);
|
|
CK_LIST_INSERT_HEAD(NCHHASH(hash), ncp, nc_hash);
|
|
}
|
|
}
|
|
ncsize = newncsize;
|
|
cache_unlock_all_buckets();
|
|
cache_unlock_all_vnodes();
|
|
free(old_nchashtbl, M_VFSCACHE);
|
|
}
|
|
|
|
/*
|
|
* Invalidate all entries from and to a particular vnode.
|
|
*/
|
|
void
|
|
cache_purge(struct vnode *vp)
|
|
{
|
|
TAILQ_HEAD(, namecache) ncps;
|
|
struct namecache *ncp, *nnp;
|
|
struct mtx *vlp, *vlp2;
|
|
|
|
CTR1(KTR_VFS, "cache_purge(%p)", vp);
|
|
SDT_PROBE1(vfs, namecache, purge, done, vp);
|
|
if (LIST_EMPTY(&vp->v_cache_src) && TAILQ_EMPTY(&vp->v_cache_dst) &&
|
|
vp->v_cache_dd == NULL)
|
|
return;
|
|
TAILQ_INIT(&ncps);
|
|
vlp = VP2VNODELOCK(vp);
|
|
vlp2 = NULL;
|
|
mtx_lock(vlp);
|
|
retry:
|
|
while (!LIST_EMPTY(&vp->v_cache_src)) {
|
|
ncp = LIST_FIRST(&vp->v_cache_src);
|
|
if (!cache_zap_locked_vnode_kl2(ncp, vp, &vlp2))
|
|
goto retry;
|
|
TAILQ_INSERT_TAIL(&ncps, ncp, nc_dst);
|
|
}
|
|
while (!TAILQ_EMPTY(&vp->v_cache_dst)) {
|
|
ncp = TAILQ_FIRST(&vp->v_cache_dst);
|
|
if (!cache_zap_locked_vnode_kl2(ncp, vp, &vlp2))
|
|
goto retry;
|
|
TAILQ_INSERT_TAIL(&ncps, ncp, nc_dst);
|
|
}
|
|
ncp = vp->v_cache_dd;
|
|
if (ncp != NULL) {
|
|
KASSERT(ncp->nc_flag & NCF_ISDOTDOT,
|
|
("lost dotdot link"));
|
|
if (!cache_zap_locked_vnode_kl2(ncp, vp, &vlp2))
|
|
goto retry;
|
|
TAILQ_INSERT_TAIL(&ncps, ncp, nc_dst);
|
|
}
|
|
KASSERT(vp->v_cache_dd == NULL, ("incomplete purge"));
|
|
mtx_unlock(vlp);
|
|
if (vlp2 != NULL)
|
|
mtx_unlock(vlp2);
|
|
TAILQ_FOREACH_SAFE(ncp, &ncps, nc_dst, nnp) {
|
|
cache_free(ncp);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Invalidate all negative entries for a particular directory vnode.
|
|
*/
|
|
void
|
|
cache_purge_negative(struct vnode *vp)
|
|
{
|
|
TAILQ_HEAD(, namecache) ncps;
|
|
struct namecache *ncp, *nnp;
|
|
struct mtx *vlp;
|
|
|
|
CTR1(KTR_VFS, "cache_purge_negative(%p)", vp);
|
|
SDT_PROBE1(vfs, namecache, purge_negative, done, vp);
|
|
if (LIST_EMPTY(&vp->v_cache_src))
|
|
return;
|
|
TAILQ_INIT(&ncps);
|
|
vlp = VP2VNODELOCK(vp);
|
|
mtx_lock(vlp);
|
|
LIST_FOREACH_SAFE(ncp, &vp->v_cache_src, nc_src, nnp) {
|
|
if (!(ncp->nc_flag & NCF_NEGATIVE))
|
|
continue;
|
|
cache_zap_negative_locked_vnode_kl(ncp, vp);
|
|
TAILQ_INSERT_TAIL(&ncps, ncp, nc_dst);
|
|
}
|
|
mtx_unlock(vlp);
|
|
TAILQ_FOREACH_SAFE(ncp, &ncps, nc_dst, nnp) {
|
|
cache_free(ncp);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Flush all entries referencing a particular filesystem.
|
|
*/
|
|
void
|
|
cache_purgevfs(struct mount *mp, bool force)
|
|
{
|
|
TAILQ_HEAD(, namecache) ncps;
|
|
struct mtx *vlp1, *vlp2;
|
|
struct rwlock *blp;
|
|
struct nchashhead *bucket;
|
|
struct namecache *ncp, *nnp;
|
|
u_long i, j, n_nchash;
|
|
int error;
|
|
|
|
/* Scan hash tables for applicable entries */
|
|
SDT_PROBE1(vfs, namecache, purgevfs, done, mp);
|
|
if (!force && mp->mnt_nvnodelistsize <= ncpurgeminvnodes)
|
|
return;
|
|
TAILQ_INIT(&ncps);
|
|
n_nchash = nchash + 1;
|
|
vlp1 = vlp2 = NULL;
|
|
for (i = 0; i < numbucketlocks; i++) {
|
|
blp = (struct rwlock *)&bucketlocks[i];
|
|
rw_wlock(blp);
|
|
for (j = i; j < n_nchash; j += numbucketlocks) {
|
|
retry:
|
|
bucket = &nchashtbl[j];
|
|
CK_LIST_FOREACH_SAFE(ncp, bucket, nc_hash, nnp) {
|
|
cache_assert_bucket_locked(ncp, RA_WLOCKED);
|
|
if (ncp->nc_dvp->v_mount != mp)
|
|
continue;
|
|
error = cache_zap_wlocked_bucket_kl(ncp, blp,
|
|
&vlp1, &vlp2);
|
|
if (error != 0)
|
|
goto retry;
|
|
TAILQ_INSERT_HEAD(&ncps, ncp, nc_dst);
|
|
}
|
|
}
|
|
rw_wunlock(blp);
|
|
if (vlp1 == NULL && vlp2 == NULL)
|
|
cache_maybe_yield();
|
|
}
|
|
if (vlp1 != NULL)
|
|
mtx_unlock(vlp1);
|
|
if (vlp2 != NULL)
|
|
mtx_unlock(vlp2);
|
|
|
|
TAILQ_FOREACH_SAFE(ncp, &ncps, nc_dst, nnp) {
|
|
cache_free(ncp);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Perform canonical checks and cache lookup and pass on to filesystem
|
|
* through the vop_cachedlookup only if needed.
|
|
*/
|
|
|
|
int
|
|
vfs_cache_lookup(struct vop_lookup_args *ap)
|
|
{
|
|
struct vnode *dvp;
|
|
int error;
|
|
struct vnode **vpp = ap->a_vpp;
|
|
struct componentname *cnp = ap->a_cnp;
|
|
int flags = cnp->cn_flags;
|
|
|
|
*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 = vn_dir_check_exec(dvp, cnp);
|
|
if (error != 0)
|
|
return (error);
|
|
|
|
error = cache_lookup(dvp, vpp, cnp, NULL, NULL);
|
|
if (error == 0)
|
|
return (VOP_CACHEDLOOKUP(dvp, vpp, cnp));
|
|
if (error == -1)
|
|
return (0);
|
|
return (error);
|
|
}
|
|
|
|
/* Implementation of the getcwd syscall. */
|
|
int
|
|
sys___getcwd(struct thread *td, struct __getcwd_args *uap)
|
|
{
|
|
char *buf, *retbuf;
|
|
size_t buflen;
|
|
int error;
|
|
|
|
buflen = uap->buflen;
|
|
if (__predict_false(buflen < 2))
|
|
return (EINVAL);
|
|
if (buflen > MAXPATHLEN)
|
|
buflen = MAXPATHLEN;
|
|
|
|
buf = malloc(buflen, M_TEMP, M_WAITOK);
|
|
error = vn_getcwd(td, buf, &retbuf, &buflen);
|
|
if (error == 0)
|
|
error = copyout(retbuf, uap->buf, buflen);
|
|
free(buf, M_TEMP);
|
|
return (error);
|
|
}
|
|
|
|
int
|
|
vn_getcwd(struct thread *td, char *buf, char **retbuf, size_t *buflen)
|
|
{
|
|
struct pwd *pwd;
|
|
int error;
|
|
|
|
pwd = pwd_hold(td);
|
|
error = vn_fullpath_any(td, pwd->pwd_cdir, pwd->pwd_rdir, buf, retbuf, buflen);
|
|
pwd_drop(pwd);
|
|
|
|
#ifdef KTRACE
|
|
if (KTRPOINT(curthread, KTR_NAMEI) && error == 0)
|
|
ktrnamei(*retbuf);
|
|
#endif
|
|
return (error);
|
|
}
|
|
|
|
static int
|
|
kern___realpathat(struct thread *td, int fd, const char *path, char *buf,
|
|
size_t size, int flags, enum uio_seg pathseg)
|
|
{
|
|
struct nameidata nd;
|
|
char *retbuf, *freebuf;
|
|
int error;
|
|
|
|
if (flags != 0)
|
|
return (EINVAL);
|
|
NDINIT_ATRIGHTS(&nd, LOOKUP, FOLLOW | SAVENAME | WANTPARENT | AUDITVNODE1,
|
|
pathseg, path, fd, &cap_fstat_rights, td);
|
|
if ((error = namei(&nd)) != 0)
|
|
return (error);
|
|
error = vn_fullpath_hardlink(td, &nd, &retbuf, &freebuf, &size);
|
|
if (error == 0) {
|
|
error = copyout(retbuf, buf, size);
|
|
free(freebuf, M_TEMP);
|
|
}
|
|
NDFREE(&nd, 0);
|
|
return (error);
|
|
}
|
|
|
|
int
|
|
sys___realpathat(struct thread *td, struct __realpathat_args *uap)
|
|
{
|
|
|
|
return (kern___realpathat(td, uap->fd, uap->path, uap->buf, uap->size,
|
|
uap->flags, UIO_USERSPACE));
|
|
}
|
|
|
|
/*
|
|
* 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)
|
|
{
|
|
struct pwd *pwd;
|
|
char *buf;
|
|
size_t buflen;
|
|
int error;
|
|
|
|
if (__predict_false(vn == NULL))
|
|
return (EINVAL);
|
|
|
|
buflen = MAXPATHLEN;
|
|
buf = malloc(buflen, M_TEMP, M_WAITOK);
|
|
pwd = pwd_hold(td);
|
|
error = vn_fullpath_any(td, vn, pwd->pwd_rdir, buf, retbuf, &buflen);
|
|
pwd_drop(pwd);
|
|
|
|
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;
|
|
size_t buflen;
|
|
int error;
|
|
|
|
if (__predict_false(vn == NULL))
|
|
return (EINVAL);
|
|
buflen = MAXPATHLEN;
|
|
buf = malloc(buflen, M_TEMP, M_WAITOK);
|
|
error = vn_fullpath_any(td, vn, rootvnode, buf, retbuf, &buflen);
|
|
if (!error)
|
|
*freebuf = buf;
|
|
else
|
|
free(buf, M_TEMP);
|
|
return (error);
|
|
}
|
|
|
|
int
|
|
vn_vptocnp(struct vnode **vp, struct ucred *cred, char *buf, size_t *buflen)
|
|
{
|
|
struct vnode *dvp;
|
|
struct namecache *ncp;
|
|
struct mtx *vlp;
|
|
int error;
|
|
|
|
vlp = VP2VNODELOCK(*vp);
|
|
mtx_lock(vlp);
|
|
TAILQ_FOREACH(ncp, &((*vp)->v_cache_dst), nc_dst) {
|
|
if ((ncp->nc_flag & NCF_ISDOTDOT) == 0)
|
|
break;
|
|
}
|
|
if (ncp != NULL) {
|
|
if (*buflen < ncp->nc_nlen) {
|
|
mtx_unlock(vlp);
|
|
vrele(*vp);
|
|
counter_u64_add(numfullpathfail4, 1);
|
|
error = ENOMEM;
|
|
SDT_PROBE3(vfs, namecache, fullpath, return, error,
|
|
vp, NULL);
|
|
return (error);
|
|
}
|
|
*buflen -= ncp->nc_nlen;
|
|
memcpy(buf + *buflen, ncp->nc_name, ncp->nc_nlen);
|
|
SDT_PROBE3(vfs, namecache, fullpath, hit, ncp->nc_dvp,
|
|
ncp->nc_name, vp);
|
|
dvp = *vp;
|
|
*vp = ncp->nc_dvp;
|
|
vref(*vp);
|
|
mtx_unlock(vlp);
|
|
vrele(dvp);
|
|
return (0);
|
|
}
|
|
SDT_PROBE1(vfs, namecache, fullpath, miss, vp);
|
|
|
|
mtx_unlock(vlp);
|
|
vn_lock(*vp, LK_SHARED | LK_RETRY);
|
|
error = VOP_VPTOCNP(*vp, &dvp, cred, buf, buflen);
|
|
vput(*vp);
|
|
if (error) {
|
|
counter_u64_add(numfullpathfail2, 1);
|
|
SDT_PROBE3(vfs, namecache, fullpath, return, error, vp, NULL);
|
|
return (error);
|
|
}
|
|
|
|
*vp = dvp;
|
|
if (VN_IS_DOOMED(dvp)) {
|
|
/* forced unmount */
|
|
vrele(dvp);
|
|
error = ENOENT;
|
|
SDT_PROBE3(vfs, namecache, fullpath, return, error, vp, NULL);
|
|
return (error);
|
|
}
|
|
/*
|
|
* *vp has its use count incremented still.
|
|
*/
|
|
|
|
return (0);
|
|
}
|
|
|
|
/*
|
|
* Resolve a directory to a pathname.
|
|
*
|
|
* The name of the directory can always be found in the namecache or fetched
|
|
* from the filesystem. There is also guaranteed to be only one parent, meaning
|
|
* we can just follow vnodes up until we find the root.
|
|
*
|
|
* The vnode must be referenced.
|
|
*/
|
|
static int
|
|
vn_fullpath_dir(struct thread *td, struct vnode *vp, struct vnode *rdir,
|
|
char *buf, char **retbuf, size_t *len, bool slash_prefixed, size_t addend)
|
|
{
|
|
#ifdef KDTRACE_HOOKS
|
|
struct vnode *startvp = vp;
|
|
#endif
|
|
struct vnode *vp1;
|
|
size_t buflen;
|
|
int error;
|
|
|
|
VNPASS(vp->v_type == VDIR || VN_IS_DOOMED(vp), vp);
|
|
VNPASS(vp->v_usecount > 0, vp);
|
|
|
|
buflen = *len;
|
|
|
|
if (!slash_prefixed) {
|
|
MPASS(*len >= 2);
|
|
buflen--;
|
|
buf[buflen] = '\0';
|
|
}
|
|
|
|
error = 0;
|
|
|
|
SDT_PROBE1(vfs, namecache, fullpath, entry, vp);
|
|
counter_u64_add(numfullpathcalls, 1);
|
|
while (vp != rdir && vp != rootvnode) {
|
|
/*
|
|
* The vp vnode must be already fully constructed,
|
|
* since it is either found in namecache or obtained
|
|
* from VOP_VPTOCNP(). We may test for VV_ROOT safely
|
|
* without obtaining the vnode lock.
|
|
*/
|
|
if ((vp->v_vflag & VV_ROOT) != 0) {
|
|
vn_lock(vp, LK_RETRY | LK_SHARED);
|
|
|
|
/*
|
|
* With the vnode locked, check for races with
|
|
* unmount, forced or not. Note that we
|
|
* already verified that vp is not equal to
|
|
* the root vnode, which means that
|
|
* mnt_vnodecovered can be NULL only for the
|
|
* case of unmount.
|
|
*/
|
|
if (VN_IS_DOOMED(vp) ||
|
|
(vp1 = vp->v_mount->mnt_vnodecovered) == NULL ||
|
|
vp1->v_mountedhere != vp->v_mount) {
|
|
vput(vp);
|
|
error = ENOENT;
|
|
SDT_PROBE3(vfs, namecache, fullpath, return,
|
|
error, vp, NULL);
|
|
break;
|
|
}
|
|
|
|
vref(vp1);
|
|
vput(vp);
|
|
vp = vp1;
|
|
continue;
|
|
}
|
|
if (vp->v_type != VDIR) {
|
|
vrele(vp);
|
|
counter_u64_add(numfullpathfail1, 1);
|
|
error = ENOTDIR;
|
|
SDT_PROBE3(vfs, namecache, fullpath, return,
|
|
error, vp, NULL);
|
|
break;
|
|
}
|
|
error = vn_vptocnp(&vp, td->td_ucred, buf, &buflen);
|
|
if (error)
|
|
break;
|
|
if (buflen == 0) {
|
|
vrele(vp);
|
|
error = ENOMEM;
|
|
SDT_PROBE3(vfs, namecache, fullpath, return, error,
|
|
startvp, NULL);
|
|
break;
|
|
}
|
|
buf[--buflen] = '/';
|
|
slash_prefixed = true;
|
|
}
|
|
if (error)
|
|
return (error);
|
|
if (!slash_prefixed) {
|
|
if (buflen == 0) {
|
|
vrele(vp);
|
|
counter_u64_add(numfullpathfail4, 1);
|
|
SDT_PROBE3(vfs, namecache, fullpath, return, ENOMEM,
|
|
startvp, NULL);
|
|
return (ENOMEM);
|
|
}
|
|
buf[--buflen] = '/';
|
|
}
|
|
counter_u64_add(numfullpathfound, 1);
|
|
vrele(vp);
|
|
|
|
*retbuf = buf + buflen;
|
|
SDT_PROBE3(vfs, namecache, fullpath, return, 0, startvp, *retbuf);
|
|
*len -= buflen;
|
|
*len += addend;
|
|
return (0);
|
|
}
|
|
|
|
/*
|
|
* Resolve an arbitrary vnode to a pathname.
|
|
*
|
|
* Note 2 caveats:
|
|
* - hardlinks are not tracked, thus if the vnode is not a directory this can
|
|
* resolve to a different path than the one used to find it
|
|
* - namecache is not mandatory, meaning names are not guaranteed to be added
|
|
* (in which case resolving fails)
|
|
*/
|
|
static int
|
|
vn_fullpath_any(struct thread *td, struct vnode *vp, struct vnode *rdir,
|
|
char *buf, char **retbuf, size_t *buflen)
|
|
{
|
|
size_t orig_buflen;
|
|
bool slash_prefixed;
|
|
int error;
|
|
|
|
if (*buflen < 2)
|
|
return (EINVAL);
|
|
|
|
orig_buflen = *buflen;
|
|
|
|
vref(vp);
|
|
slash_prefixed = false;
|
|
if (vp->v_type != VDIR) {
|
|
*buflen -= 1;
|
|
buf[*buflen] = '\0';
|
|
error = vn_vptocnp(&vp, td->td_ucred, buf, buflen);
|
|
if (error)
|
|
return (error);
|
|
if (*buflen == 0) {
|
|
vrele(vp);
|
|
return (ENOMEM);
|
|
}
|
|
*buflen -= 1;
|
|
buf[*buflen] = '/';
|
|
slash_prefixed = true;
|
|
}
|
|
|
|
return (vn_fullpath_dir(td, vp, rdir, buf, retbuf, buflen, slash_prefixed,
|
|
orig_buflen - *buflen));
|
|
}
|
|
|
|
/*
|
|
* Resolve an arbitrary vnode to a pathname (taking care of hardlinks).
|
|
*
|
|
* Since the namecache does not track handlings, the caller is expected to first
|
|
* look up the target vnode with SAVENAME | WANTPARENT flags passed to namei.
|
|
*
|
|
* Then we have 2 cases:
|
|
* - if the found vnode is a directory, the path can be constructed just by
|
|
* fullowing names up the chain
|
|
* - otherwise we populate the buffer with the saved name and start resolving
|
|
* from the parent
|
|
*/
|
|
static int
|
|
vn_fullpath_hardlink(struct thread *td, struct nameidata *ndp, char **retbuf,
|
|
char **freebuf, size_t *buflen)
|
|
{
|
|
char *buf, *tmpbuf;
|
|
struct pwd *pwd;
|
|
struct componentname *cnp;
|
|
struct vnode *vp;
|
|
size_t addend;
|
|
int error;
|
|
bool slash_prefixed;
|
|
|
|
if (*buflen < 2)
|
|
return (EINVAL);
|
|
if (*buflen > MAXPATHLEN)
|
|
*buflen = MAXPATHLEN;
|
|
|
|
slash_prefixed = false;
|
|
|
|
buf = malloc(*buflen, M_TEMP, M_WAITOK);
|
|
pwd = pwd_hold(td);
|
|
|
|
addend = 0;
|
|
vp = ndp->ni_vp;
|
|
if (vp->v_type != VDIR) {
|
|
cnp = &ndp->ni_cnd;
|
|
addend = cnp->cn_namelen + 2;
|
|
if (*buflen < addend) {
|
|
error = ENOMEM;
|
|
goto out_bad;
|
|
}
|
|
*buflen -= addend;
|
|
tmpbuf = buf + *buflen;
|
|
tmpbuf[0] = '/';
|
|
memcpy(&tmpbuf[1], cnp->cn_nameptr, cnp->cn_namelen);
|
|
tmpbuf[addend - 1] = '\0';
|
|
slash_prefixed = true;
|
|
vp = ndp->ni_dvp;
|
|
}
|
|
|
|
vref(vp);
|
|
error = vn_fullpath_dir(td, vp, pwd->pwd_rdir, buf, retbuf, buflen,
|
|
slash_prefixed, addend);
|
|
if (error != 0)
|
|
goto out_bad;
|
|
|
|
pwd_drop(pwd);
|
|
*freebuf = buf;
|
|
|
|
return (0);
|
|
out_bad:
|
|
pwd_drop(pwd);
|
|
free(buf, M_TEMP);
|
|
return (error);
|
|
}
|
|
|
|
struct vnode *
|
|
vn_dir_dd_ino(struct vnode *vp)
|
|
{
|
|
struct namecache *ncp;
|
|
struct vnode *ddvp;
|
|
struct mtx *vlp;
|
|
enum vgetstate vs;
|
|
|
|
ASSERT_VOP_LOCKED(vp, "vn_dir_dd_ino");
|
|
vlp = VP2VNODELOCK(vp);
|
|
mtx_lock(vlp);
|
|
TAILQ_FOREACH(ncp, &(vp->v_cache_dst), nc_dst) {
|
|
if ((ncp->nc_flag & NCF_ISDOTDOT) != 0)
|
|
continue;
|
|
ddvp = ncp->nc_dvp;
|
|
vs = vget_prep(ddvp);
|
|
mtx_unlock(vlp);
|
|
if (vget_finish(ddvp, LK_SHARED | LK_NOWAIT, vs))
|
|
return (NULL);
|
|
return (ddvp);
|
|
}
|
|
mtx_unlock(vlp);
|
|
return (NULL);
|
|
}
|
|
|
|
int
|
|
vn_commname(struct vnode *vp, char *buf, u_int buflen)
|
|
{
|
|
struct namecache *ncp;
|
|
struct mtx *vlp;
|
|
int l;
|
|
|
|
vlp = VP2VNODELOCK(vp);
|
|
mtx_lock(vlp);
|
|
TAILQ_FOREACH(ncp, &vp->v_cache_dst, nc_dst)
|
|
if ((ncp->nc_flag & NCF_ISDOTDOT) == 0)
|
|
break;
|
|
if (ncp == NULL) {
|
|
mtx_unlock(vlp);
|
|
return (ENOENT);
|
|
}
|
|
l = min(ncp->nc_nlen, buflen - 1);
|
|
memcpy(buf, ncp->nc_name, l);
|
|
mtx_unlock(vlp);
|
|
buf[l] = '\0';
|
|
return (0);
|
|
}
|
|
|
|
/*
|
|
* This function updates path string to vnode's full global path
|
|
* and checks the size of the new path string against the pathlen argument.
|
|
*
|
|
* Requires a locked, referenced vnode.
|
|
* Vnode is re-locked on success or ENODEV, otherwise unlocked.
|
|
*
|
|
* If vp is a directory, the call to vn_fullpath_global() always succeeds
|
|
* because it falls back to the ".." lookup if the namecache lookup fails.
|
|
*/
|
|
int
|
|
vn_path_to_global_path(struct thread *td, struct vnode *vp, char *path,
|
|
u_int pathlen)
|
|
{
|
|
struct nameidata nd;
|
|
struct vnode *vp1;
|
|
char *rpath, *fbuf;
|
|
int error;
|
|
|
|
ASSERT_VOP_ELOCKED(vp, __func__);
|
|
|
|
/* Construct global filesystem path from vp. */
|
|
VOP_UNLOCK(vp);
|
|
error = vn_fullpath_global(td, vp, &rpath, &fbuf);
|
|
|
|
if (error != 0) {
|
|
vrele(vp);
|
|
return (error);
|
|
}
|
|
|
|
if (strlen(rpath) >= pathlen) {
|
|
vrele(vp);
|
|
error = ENAMETOOLONG;
|
|
goto out;
|
|
}
|
|
|
|
/*
|
|
* Re-lookup the vnode by path to detect a possible rename.
|
|
* As a side effect, the vnode is relocked.
|
|
* If vnode was renamed, return ENOENT.
|
|
*/
|
|
NDINIT(&nd, LOOKUP, FOLLOW | LOCKLEAF | AUDITVNODE1,
|
|
UIO_SYSSPACE, path, td);
|
|
error = namei(&nd);
|
|
if (error != 0) {
|
|
vrele(vp);
|
|
goto out;
|
|
}
|
|
NDFREE(&nd, NDF_ONLY_PNBUF);
|
|
vp1 = nd.ni_vp;
|
|
vrele(vp);
|
|
if (vp1 == vp)
|
|
strcpy(path, rpath);
|
|
else {
|
|
vput(vp1);
|
|
error = ENOENT;
|
|
}
|
|
|
|
out:
|
|
free(fbuf, M_TEMP);
|
|
return (error);
|
|
}
|
|
|
|
#ifdef DDB
|
|
static void
|
|
db_print_vpath(struct vnode *vp)
|
|
{
|
|
|
|
while (vp != NULL) {
|
|
db_printf("%p: ", vp);
|
|
if (vp == rootvnode) {
|
|
db_printf("/");
|
|
vp = NULL;
|
|
} else {
|
|
if (vp->v_vflag & VV_ROOT) {
|
|
db_printf("<mount point>");
|
|
vp = vp->v_mount->mnt_vnodecovered;
|
|
} else {
|
|
struct namecache *ncp;
|
|
char *ncn;
|
|
int i;
|
|
|
|
ncp = TAILQ_FIRST(&vp->v_cache_dst);
|
|
if (ncp != NULL) {
|
|
ncn = ncp->nc_name;
|
|
for (i = 0; i < ncp->nc_nlen; i++)
|
|
db_printf("%c", *ncn++);
|
|
vp = ncp->nc_dvp;
|
|
} else {
|
|
vp = NULL;
|
|
}
|
|
}
|
|
}
|
|
db_printf("\n");
|
|
}
|
|
|
|
return;
|
|
}
|
|
|
|
DB_SHOW_COMMAND(vpath, db_show_vpath)
|
|
{
|
|
struct vnode *vp;
|
|
|
|
if (!have_addr) {
|
|
db_printf("usage: show vpath <struct vnode *>\n");
|
|
return;
|
|
}
|
|
|
|
vp = (struct vnode *)addr;
|
|
db_print_vpath(vp);
|
|
}
|
|
|
|
#endif
|