5458 lines
134 KiB
C
5458 lines
134 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/jail.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/seqc.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 INVARIANTS
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#include <machine/_inttypes.h>
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#endif
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#include <sys/capsicum.h>
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#include <security/audit/audit.h>
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#include <security/mac/mac_framework.h>
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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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static SYSCTL_NODE(_vfs, OID_AUTO, cache, CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
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"Name cache");
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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_DEFINE3(vfs, namecache, enter, duplicate, "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_DEFINE2(vfs, namecache, fullpath_smr, hit, "struct vnode *",
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"const char *");
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SDT_PROBE_DEFINE4(vfs, namecache, fullpath_smr, miss, "struct vnode *",
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"struct namecache *", "int", "int");
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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_DEFINE2(vfs, namecache, removecnp, hit, "struct vnode *",
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"struct componentname *");
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SDT_PROBE_DEFINE2(vfs, namecache, removecnp, miss, "struct vnode *",
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"struct componentname *");
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SDT_PROBE_DEFINE1(vfs, namecache, purge, done, "struct vnode *");
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SDT_PROBE_DEFINE1(vfs, namecache, purge, batch, "int");
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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, evict_negative, done, "struct vnode *",
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"char *");
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SDT_PROBE_DEFINE3(vfs, fplookup, lookup, done, "struct nameidata", "int", "bool");
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SDT_PROBE_DECLARE(vfs, namei, lookup, entry);
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SDT_PROBE_DECLARE(vfs, namei, lookup, return);
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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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u_char neg_hit;
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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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LIST_ENTRY(namecache) nc_src; /* source vnode list */
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TAILQ_ENTRY(namecache) nc_dst; /* destination vnode list */
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CK_SLIST_ENTRY(namecache) nc_hash;/* hash chain */
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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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* See below for alignment requirement.
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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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int nc_pad;
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struct namecache nc_nc;
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};
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TAILQ_HEAD(cache_freebatch, namecache);
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/*
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* At least mips n32 performs 64-bit accesses to timespec as found
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* in namecache_ts and requires them to be aligned. Since others
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* may be in the same spot suffer a little bit and enforce the
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* alignment for everyone. Note this is a nop for 64-bit platforms.
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*/
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#define CACHE_ZONE_ALIGNMENT UMA_ALIGNOF(time_t)
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/*
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* TODO: the initial value of CACHE_PATH_CUTOFF was inherited from the
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* 4.4 BSD codebase. Later on struct namecache was tweaked to become
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* smaller and the value was bumped to retain the total size, but it
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* was never re-evaluated for suitability. A simple test counting
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* lengths during package building shows that the value of 45 covers
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* about 86% of all added entries, reaching 99% at 65.
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*
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* Regardless of the above, use of dedicated zones instead of malloc may be
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* inducing additional waste. This may be hard to address as said zones are
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* tied to VFS SMR. Even if retaining them, the current split should be
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* re-evaluated.
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*/
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#ifdef __LP64__
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#define CACHE_PATH_CUTOFF 45
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#define CACHE_LARGE_PAD 6
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#else
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#define CACHE_PATH_CUTOFF 41
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#define CACHE_LARGE_PAD 2
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#endif
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#define CACHE_ZONE_SMALL_SIZE (offsetof(struct namecache, nc_name) + CACHE_PATH_CUTOFF + 1)
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#define CACHE_ZONE_SMALL_TS_SIZE (offsetof(struct namecache_ts, nc_nc) + CACHE_ZONE_SMALL_SIZE)
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#define CACHE_ZONE_LARGE_SIZE (offsetof(struct namecache, nc_name) + NAME_MAX + 1 + CACHE_LARGE_PAD)
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#define CACHE_ZONE_LARGE_TS_SIZE (offsetof(struct namecache_ts, nc_nc) + CACHE_ZONE_LARGE_SIZE)
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_Static_assert((CACHE_ZONE_SMALL_SIZE % (CACHE_ZONE_ALIGNMENT + 1)) == 0, "bad zone size");
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_Static_assert((CACHE_ZONE_SMALL_TS_SIZE % (CACHE_ZONE_ALIGNMENT + 1)) == 0, "bad zone size");
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_Static_assert((CACHE_ZONE_LARGE_SIZE % (CACHE_ZONE_ALIGNMENT + 1)) == 0, "bad zone size");
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_Static_assert((CACHE_ZONE_LARGE_TS_SIZE % (CACHE_ZONE_ALIGNMENT + 1)) == 0, "bad zone size");
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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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#define NCF_WIP 0x80
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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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static bool cache_neg_evict_cond(u_long lnumcache);
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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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atomic_store_char(&ncp->nc_flag, 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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* Check whether the entry can be safely used.
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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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#define cache_ncp_canuse(ncp) ({ \
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struct namecache *_ncp = (ncp); \
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u_char _nc_flag; \
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\
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atomic_thread_fence_acq(); \
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_nc_flag = atomic_load_char(&_ncp->nc_flag); \
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__predict_true((_nc_flag & (NCF_INVALID | NCF_WIP)) == 0); \
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})
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/*
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* Like the above but also checks NCF_WHITE.
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*/
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#define cache_fpl_neg_ncp_canuse(ncp) ({ \
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struct namecache *_ncp = (ncp); \
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u_char _nc_flag; \
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\
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atomic_thread_fence_acq(); \
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_nc_flag = atomic_load_char(&_ncp->nc_flag); \
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__predict_true((_nc_flag & (NCF_INVALID | NCF_WIP | NCF_WHITE)) == 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 mtx 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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* 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 locked to provide safe operation against other threads modifying the
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* cache.
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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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static SYSCTL_NODE(_vfs_cache, OID_AUTO, param, CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
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"Name cache parameters");
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static u_int __read_mostly ncsize; /* the size as computed on creation or resizing */
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SYSCTL_UINT(_vfs_cache_param, OID_AUTO, size, CTLFLAG_RW, &ncsize, 0,
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"Total namecache capacity");
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u_int ncsizefactor = 2;
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SYSCTL_UINT(_vfs_cache_param, OID_AUTO, sizefactor, CTLFLAG_RW, &ncsizefactor, 0,
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"Size factor for namecache");
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static u_long __read_mostly ncnegfactor = 5; /* ratio of negative entries */
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SYSCTL_ULONG(_vfs_cache_param, OID_AUTO, negfactor, CTLFLAG_RW, &ncnegfactor, 0,
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"Ratio of negative namecache entries");
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/*
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* Negative entry % of namecache capacity above which automatic eviction is allowed.
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*
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* Check cache_neg_evict_cond for details.
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*/
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static u_int ncnegminpct = 3;
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static u_int __read_mostly neg_min; /* the above recomputed against ncsize */
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SYSCTL_UINT(_vfs_cache_param, OID_AUTO, negmin, CTLFLAG_RD, &neg_min, 0,
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"Negative entry count above which automatic eviction is allowed");
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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_SLIST_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 __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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struct nchstats nchstats; /* cache effectiveness statistics */
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static bool __read_frequently cache_fast_revlookup = true;
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SYSCTL_BOOL(_vfs, OID_AUTO, cache_fast_revlookup, CTLFLAG_RW,
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&cache_fast_revlookup, 0, "");
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static u_int __exclusive_cache_line neg_cycle;
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#define ncneghash 3
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#define numneglists (ncneghash + 1)
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struct neglist {
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struct mtx nl_evict_lock;
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struct mtx nl_lock __aligned(CACHE_LINE_SIZE);
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TAILQ_HEAD(, namecache) nl_list;
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TAILQ_HEAD(, namecache) nl_hotlist;
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u_long nl_hotnum;
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} __aligned(CACHE_LINE_SIZE);
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static struct neglist neglists[numneglists];
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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 mtx_padalign __read_mostly *bucketlocks;
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#define HASH2BUCKETLOCK(hash) \
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((struct mtx *)(&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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static void
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cache_out_ts(struct namecache *ncp, struct timespec *tsp, int *ticksp)
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{
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struct namecache_ts *ncp_ts;
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KASSERT((ncp->nc_flag & NCF_TS) != 0 ||
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(tsp == NULL && ticksp == NULL),
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("No NCF_TS"));
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if (tsp == NULL)
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return;
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ncp_ts = __containerof(ncp, struct namecache_ts, nc_nc);
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*tsp = ncp_ts->nc_time;
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*ticksp = ncp_ts->nc_ticks;
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}
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#ifdef DEBUG_CACHE
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static int __read_mostly doingcache = 1; /* 1 => enable the cache */
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SYSCTL_INT(_debug, OID_AUTO, vfscache, CTLFLAG_RW, &doingcache, 0,
|
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"VFS namecache enabled");
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#endif
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|
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/* Export size information to userland */
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|
SYSCTL_INT(_debug_sizeof, OID_AUTO, namecache, CTLFLAG_RD, SYSCTL_NULL_INT_PTR,
|
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sizeof(struct namecache), "sizeof(struct namecache)");
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/*
|
|
* The new name cache statistics
|
|
*/
|
|
static SYSCTL_NODE(_vfs_cache, OID_AUTO, stats, CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
|
|
"Name cache statistics");
|
|
|
|
#define STATNODE_ULONG(name, varname, descr) \
|
|
SYSCTL_ULONG(_vfs_cache_stats, OID_AUTO, name, CTLFLAG_RD, &varname, 0, descr);
|
|
#define STATNODE_COUNTER(name, varname, descr) \
|
|
static COUNTER_U64_DEFINE_EARLY(varname); \
|
|
SYSCTL_COUNTER_U64(_vfs_cache_stats, OID_AUTO, name, CTLFLAG_RD, &varname, \
|
|
descr);
|
|
STATNODE_ULONG(neg, numneg, "Number of negative cache entries");
|
|
STATNODE_ULONG(count, numcache, "Number of cache entries");
|
|
STATNODE_COUNTER(heldvnodes, numcachehv, "Number of namecache entries with vnodes held");
|
|
STATNODE_COUNTER(drops, numdrops, "Number of dropped entries due to reaching the limit");
|
|
STATNODE_COUNTER(dothits, dothits, "Number of '.' hits");
|
|
STATNODE_COUNTER(dotdothis, dotdothits, "Number of '..' hits");
|
|
STATNODE_COUNTER(miss, nummiss, "Number of cache misses");
|
|
STATNODE_COUNTER(misszap, nummisszap, "Number of cache misses we do not want to cache");
|
|
STATNODE_COUNTER(posszaps, numposzaps,
|
|
"Number of cache hits (positive) we do not want to cache");
|
|
STATNODE_COUNTER(poshits, numposhits, "Number of cache hits (positive)");
|
|
STATNODE_COUNTER(negzaps, numnegzaps,
|
|
"Number of cache hits (negative) we do not want to cache");
|
|
STATNODE_COUNTER(neghits, numneghits, "Number of cache hits (negative)");
|
|
/* These count for vn_getcwd(), too. */
|
|
STATNODE_COUNTER(fullpathcalls, numfullpathcalls, "Number of fullpath search calls");
|
|
STATNODE_COUNTER(fullpathfail1, numfullpathfail1, "Number of fullpath search errors (ENOTDIR)");
|
|
STATNODE_COUNTER(fullpathfail2, numfullpathfail2,
|
|
"Number of fullpath search errors (VOP_VPTOCNP failures)");
|
|
STATNODE_COUNTER(fullpathfail4, numfullpathfail4, "Number of fullpath search errors (ENOMEM)");
|
|
STATNODE_COUNTER(fullpathfound, numfullpathfound, "Number of successful fullpath calls");
|
|
|
|
/*
|
|
* Debug or developer statistics.
|
|
*/
|
|
static SYSCTL_NODE(_vfs_cache, OID_AUTO, debug, CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
|
|
"Name cache debugging");
|
|
#define DEBUGNODE_ULONG(name, varname, descr) \
|
|
SYSCTL_ULONG(_vfs_cache_debug, OID_AUTO, name, CTLFLAG_RD, &varname, 0, descr);
|
|
#define DEBUGNODE_COUNTER(name, varname, descr) \
|
|
static COUNTER_U64_DEFINE_EARLY(varname); \
|
|
SYSCTL_COUNTER_U64(_vfs_cache_debug, OID_AUTO, name, CTLFLAG_RD, &varname, \
|
|
descr);
|
|
DEBUGNODE_COUNTER(zap_bucket_relock_success, zap_bucket_relock_success,
|
|
"Number of successful removals after relocking");
|
|
static long zap_bucket_fail;
|
|
DEBUGNODE_ULONG(zap_bucket_fail, zap_bucket_fail, "");
|
|
static long zap_bucket_fail2;
|
|
DEBUGNODE_ULONG(zap_bucket_fail2, zap_bucket_fail2, "");
|
|
static long cache_lock_vnodes_cel_3_failures;
|
|
DEBUGNODE_ULONG(vnodes_cel_3_failures, cache_lock_vnodes_cel_3_failures,
|
|
"Number of times 3-way vnode locking failed");
|
|
|
|
static void cache_zap_locked(struct namecache *ncp);
|
|
static int vn_fullpath_hardlink(struct nameidata *ndp, char **retbuf,
|
|
char **freebuf, size_t *buflen);
|
|
static int vn_fullpath_any_smr(struct vnode *vp, struct vnode *rdir, char *buf,
|
|
char **retbuf, size_t *buflen, size_t addend);
|
|
static int vn_fullpath_any(struct vnode *vp, struct vnode *rdir, char *buf,
|
|
char **retbuf, size_t *buflen);
|
|
static int vn_fullpath_dir(struct vnode *vp, struct vnode *rdir, char *buf,
|
|
char **retbuf, size_t *len, size_t addend);
|
|
|
|
static MALLOC_DEFINE(M_VFSCACHE, "vfscache", "VFS name cache entries");
|
|
|
|
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);
|
|
}
|
|
|
|
/*
|
|
* Directory vnodes with entries are held for two reasons:
|
|
* 1. make them less of a target for reclamation in vnlru
|
|
* 2. suffer smaller performance penalty in locked lookup as requeieing is avoided
|
|
*
|
|
* It will be feasible to stop doing it altogether if all filesystems start
|
|
* supporting lockless lookup.
|
|
*/
|
|
static void
|
|
cache_hold_vnode(struct vnode *vp)
|
|
{
|
|
|
|
cache_assert_vnode_locked(vp);
|
|
VNPASS(LIST_EMPTY(&vp->v_cache_src), vp);
|
|
vhold(vp);
|
|
counter_u64_add(numcachehv, 1);
|
|
}
|
|
|
|
static void
|
|
cache_drop_vnode(struct vnode *vp)
|
|
{
|
|
|
|
/*
|
|
* Called after all locks are dropped, meaning we can't assert
|
|
* on the state of v_cache_src.
|
|
*/
|
|
vdrop(vp);
|
|
counter_u64_add(numcachehv, -1);
|
|
}
|
|
|
|
/*
|
|
* UMA zones.
|
|
*/
|
|
static uma_zone_t __read_mostly cache_zone_small;
|
|
static uma_zone_t __read_mostly cache_zone_small_ts;
|
|
static uma_zone_t __read_mostly cache_zone_large;
|
|
static uma_zone_t __read_mostly cache_zone_large_ts;
|
|
|
|
static struct namecache *
|
|
cache_alloc_uma(int len, bool ts)
|
|
{
|
|
struct namecache_ts *ncp_ts;
|
|
struct namecache *ncp;
|
|
|
|
if (__predict_false(ts)) {
|
|
if (len <= CACHE_PATH_CUTOFF)
|
|
ncp_ts = uma_zalloc_smr(cache_zone_small_ts, M_WAITOK);
|
|
else
|
|
ncp_ts = uma_zalloc_smr(cache_zone_large_ts, M_WAITOK);
|
|
ncp = &ncp_ts->nc_nc;
|
|
} else {
|
|
if (len <= CACHE_PATH_CUTOFF)
|
|
ncp = uma_zalloc_smr(cache_zone_small, M_WAITOK);
|
|
else
|
|
ncp = uma_zalloc_smr(cache_zone_large, M_WAITOK);
|
|
}
|
|
return (ncp);
|
|
}
|
|
|
|
static void
|
|
cache_free_uma(struct namecache *ncp)
|
|
{
|
|
struct namecache_ts *ncp_ts;
|
|
|
|
if (__predict_false(ncp->nc_flag & NCF_TS)) {
|
|
ncp_ts = __containerof(ncp, struct namecache_ts, nc_nc);
|
|
if (ncp->nc_nlen <= CACHE_PATH_CUTOFF)
|
|
uma_zfree_smr(cache_zone_small_ts, ncp_ts);
|
|
else
|
|
uma_zfree_smr(cache_zone_large_ts, ncp_ts);
|
|
} else {
|
|
if (ncp->nc_nlen <= CACHE_PATH_CUTOFF)
|
|
uma_zfree_smr(cache_zone_small, ncp);
|
|
else
|
|
uma_zfree_smr(cache_zone_large, ncp);
|
|
}
|
|
}
|
|
|
|
static struct namecache *
|
|
cache_alloc(int len, bool ts)
|
|
{
|
|
u_long lnumcache;
|
|
|
|
/*
|
|
* Avoid blowout in namecache entries.
|
|
*
|
|
* Bugs:
|
|
* 1. filesystems may end up trying to add an already existing entry
|
|
* (for example this can happen after a cache miss during concurrent
|
|
* lookup), in which case we will call cache_neg_evict despite not
|
|
* adding anything.
|
|
* 2. the routine may fail to free anything and no provisions are made
|
|
* to make it try harder (see the inside for failure modes)
|
|
* 3. it only ever looks at negative entries.
|
|
*/
|
|
lnumcache = atomic_fetchadd_long(&numcache, 1) + 1;
|
|
if (cache_neg_evict_cond(lnumcache)) {
|
|
lnumcache = atomic_load_long(&numcache);
|
|
}
|
|
if (__predict_false(lnumcache >= ncsize)) {
|
|
atomic_subtract_long(&numcache, 1);
|
|
counter_u64_add(numdrops, 1);
|
|
return (NULL);
|
|
}
|
|
return (cache_alloc_uma(len, ts));
|
|
}
|
|
|
|
static void
|
|
cache_free(struct namecache *ncp)
|
|
{
|
|
|
|
MPASS(ncp != NULL);
|
|
if ((ncp->nc_flag & NCF_DVDROP) != 0) {
|
|
cache_drop_vnode(ncp->nc_dvp);
|
|
}
|
|
cache_free_uma(ncp);
|
|
atomic_subtract_long(&numcache, 1);
|
|
}
|
|
|
|
static void
|
|
cache_free_batch(struct cache_freebatch *batch)
|
|
{
|
|
struct namecache *ncp, *nnp;
|
|
int i;
|
|
|
|
i = 0;
|
|
if (TAILQ_EMPTY(batch))
|
|
goto out;
|
|
TAILQ_FOREACH_SAFE(ncp, batch, nc_dst, nnp) {
|
|
if ((ncp->nc_flag & NCF_DVDROP) != 0) {
|
|
cache_drop_vnode(ncp->nc_dvp);
|
|
}
|
|
cache_free_uma(ncp);
|
|
i++;
|
|
}
|
|
atomic_subtract_long(&numcache, i);
|
|
out:
|
|
SDT_PROBE1(vfs, namecache, purge, batch, i);
|
|
}
|
|
|
|
/*
|
|
* TODO: With the value stored we can do better than computing the hash based
|
|
* on the address. The choice of FNV should also be revisited.
|
|
*/
|
|
static void
|
|
cache_prehash(struct vnode *vp)
|
|
{
|
|
|
|
vp->v_nchash = fnv_32_buf(&vp, sizeof(vp), FNV1_32_INIT);
|
|
}
|
|
|
|
static uint32_t
|
|
cache_get_hash(char *name, u_char len, struct vnode *dvp)
|
|
{
|
|
|
|
return (fnv_32_buf(name, len, dvp->v_nchash));
|
|
}
|
|
|
|
static inline struct nchashhead *
|
|
NCP2BUCKET(struct namecache *ncp)
|
|
{
|
|
uint32_t hash;
|
|
|
|
hash = cache_get_hash(ncp->nc_name, ncp->nc_nlen, ncp->nc_dvp);
|
|
return (NCHHASH(hash));
|
|
}
|
|
|
|
static inline struct mtx *
|
|
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)
|
|
{
|
|
struct mtx *blp;
|
|
|
|
blp = NCP2BUCKETLOCK(ncp);
|
|
mtx_assert(blp, MA_OWNED);
|
|
}
|
|
|
|
static void
|
|
cache_assert_bucket_unlocked(struct namecache *ncp)
|
|
{
|
|
struct mtx *blp;
|
|
|
|
blp = NCP2BUCKETLOCK(ncp);
|
|
mtx_assert(blp, MA_NOTOWNED);
|
|
}
|
|
#else
|
|
#define cache_assert_bucket_locked(x) do { } while (0)
|
|
#define cache_assert_bucket_unlocked(x) 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++)
|
|
mtx_lock(&bucketlocks[i]);
|
|
}
|
|
|
|
static void
|
|
cache_unlock_all_buckets(void)
|
|
{
|
|
u_int i;
|
|
|
|
for (i = 0; i < numbucketlocks; i++)
|
|
mtx_unlock(&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");
|
|
|
|
static void
|
|
cache_recalc_neg_min(u_int val)
|
|
{
|
|
|
|
neg_min = (ncsize * val) / 100;
|
|
}
|
|
|
|
static int
|
|
sysctl_negminpct(SYSCTL_HANDLER_ARGS)
|
|
{
|
|
u_int val;
|
|
int error;
|
|
|
|
val = ncnegminpct;
|
|
error = sysctl_handle_int(oidp, &val, 0, req);
|
|
if (error != 0 || req->newptr == NULL)
|
|
return (error);
|
|
|
|
if (val == ncnegminpct)
|
|
return (0);
|
|
if (val < 0 || val > 99)
|
|
return (EINVAL);
|
|
ncnegminpct = val;
|
|
cache_recalc_neg_min(val);
|
|
return (0);
|
|
}
|
|
|
|
SYSCTL_PROC(_vfs_cache_param, OID_AUTO, negminpct,
|
|
CTLTYPE_INT | CTLFLAG_MPSAFE | CTLFLAG_RW, NULL, 0, sysctl_negminpct,
|
|
"I", "Negative entry \% of namecache capacity above which automatic eviction is allowed");
|
|
|
|
#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_SLIST_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_SLIST_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
|
|
*
|
|
* Various workloads create plenty of negative entries and barely use them
|
|
* afterwards. Moreover malicious users can keep performing bogus lookups
|
|
* adding even more entries. For example "make tinderbox" as of writing this
|
|
* comment ends up with 2.6M namecache entries in total, 1.2M of which are
|
|
* negative.
|
|
*
|
|
* As such, a rather aggressive eviction method is needed. The currently
|
|
* employed method is a placeholder.
|
|
*
|
|
* Entries are split over numneglists separate lists, each of which is further
|
|
* split into hot and cold entries. Entries get promoted after getting a hit.
|
|
* Eviction happens on addition of new entry.
|
|
*/
|
|
static SYSCTL_NODE(_vfs_cache, OID_AUTO, neg, CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
|
|
"Name cache negative entry statistics");
|
|
|
|
SYSCTL_ULONG(_vfs_cache_neg, OID_AUTO, count, CTLFLAG_RD, &numneg, 0,
|
|
"Number of negative cache entries");
|
|
|
|
static COUNTER_U64_DEFINE_EARLY(neg_created);
|
|
SYSCTL_COUNTER_U64(_vfs_cache_neg, OID_AUTO, created, CTLFLAG_RD, &neg_created,
|
|
"Number of created negative entries");
|
|
|
|
static COUNTER_U64_DEFINE_EARLY(neg_evicted);
|
|
SYSCTL_COUNTER_U64(_vfs_cache_neg, OID_AUTO, evicted, CTLFLAG_RD, &neg_evicted,
|
|
"Number of evicted negative entries");
|
|
|
|
static COUNTER_U64_DEFINE_EARLY(neg_evict_skipped_empty);
|
|
SYSCTL_COUNTER_U64(_vfs_cache_neg, OID_AUTO, evict_skipped_empty, CTLFLAG_RD,
|
|
&neg_evict_skipped_empty,
|
|
"Number of times evicting failed due to lack of entries");
|
|
|
|
static COUNTER_U64_DEFINE_EARLY(neg_evict_skipped_missed);
|
|
SYSCTL_COUNTER_U64(_vfs_cache_neg, OID_AUTO, evict_skipped_missed, CTLFLAG_RD,
|
|
&neg_evict_skipped_missed,
|
|
"Number of times evicting failed due to target entry disappearing");
|
|
|
|
static COUNTER_U64_DEFINE_EARLY(neg_evict_skipped_contended);
|
|
SYSCTL_COUNTER_U64(_vfs_cache_neg, OID_AUTO, evict_skipped_contended, CTLFLAG_RD,
|
|
&neg_evict_skipped_contended,
|
|
"Number of times evicting failed due to contention");
|
|
|
|
SYSCTL_COUNTER_U64(_vfs_cache_neg, OID_AUTO, hits, CTLFLAG_RD, &numneghits,
|
|
"Number of cache hits (negative)");
|
|
|
|
static int
|
|
sysctl_neg_hot(SYSCTL_HANDLER_ARGS)
|
|
{
|
|
int i, out;
|
|
|
|
out = 0;
|
|
for (i = 0; i < numneglists; i++)
|
|
out += neglists[i].nl_hotnum;
|
|
|
|
return (SYSCTL_OUT(req, &out, sizeof(out)));
|
|
}
|
|
SYSCTL_PROC(_vfs_cache_neg, OID_AUTO, hot, CTLTYPE_INT | CTLFLAG_RD |
|
|
CTLFLAG_MPSAFE, 0, 0, sysctl_neg_hot, "I",
|
|
"Number of hot negative entries");
|
|
|
|
static void
|
|
cache_neg_init(struct namecache *ncp)
|
|
{
|
|
struct negstate *ns;
|
|
|
|
ncp->nc_flag |= NCF_NEGATIVE;
|
|
ns = NCP2NEGSTATE(ncp);
|
|
ns->neg_flag = 0;
|
|
ns->neg_hit = 0;
|
|
counter_u64_add(neg_created, 1);
|
|
}
|
|
|
|
#define CACHE_NEG_PROMOTION_THRESH 2
|
|
|
|
static bool
|
|
cache_neg_hit_prep(struct namecache *ncp)
|
|
{
|
|
struct negstate *ns;
|
|
u_char n;
|
|
|
|
ns = NCP2NEGSTATE(ncp);
|
|
n = atomic_load_char(&ns->neg_hit);
|
|
for (;;) {
|
|
if (n >= CACHE_NEG_PROMOTION_THRESH)
|
|
return (false);
|
|
if (atomic_fcmpset_8(&ns->neg_hit, &n, n + 1))
|
|
break;
|
|
}
|
|
return (n + 1 == CACHE_NEG_PROMOTION_THRESH);
|
|
}
|
|
|
|
/*
|
|
* Nothing to do here but it is provided for completeness as some
|
|
* cache_neg_hit_prep callers may end up returning without even
|
|
* trying to promote.
|
|
*/
|
|
#define cache_neg_hit_abort(ncp) do { } while (0)
|
|
|
|
static void
|
|
cache_neg_hit_finish(struct namecache *ncp)
|
|
{
|
|
|
|
SDT_PROBE2(vfs, namecache, lookup, hit__negative, ncp->nc_dvp, ncp->nc_name);
|
|
counter_u64_add(numneghits, 1);
|
|
}
|
|
|
|
/*
|
|
* Move a negative entry to the hot list.
|
|
*/
|
|
static void
|
|
cache_neg_promote_locked(struct namecache *ncp)
|
|
{
|
|
struct neglist *nl;
|
|
struct negstate *ns;
|
|
|
|
ns = NCP2NEGSTATE(ncp);
|
|
nl = NCP2NEGLIST(ncp);
|
|
mtx_assert(&nl->nl_lock, MA_OWNED);
|
|
if ((ns->neg_flag & NEG_HOT) == 0) {
|
|
TAILQ_REMOVE(&nl->nl_list, ncp, nc_dst);
|
|
TAILQ_INSERT_TAIL(&nl->nl_hotlist, ncp, nc_dst);
|
|
nl->nl_hotnum++;
|
|
ns->neg_flag |= NEG_HOT;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Move a hot negative entry to the cold list.
|
|
*/
|
|
static void
|
|
cache_neg_demote_locked(struct namecache *ncp)
|
|
{
|
|
struct neglist *nl;
|
|
struct negstate *ns;
|
|
|
|
ns = NCP2NEGSTATE(ncp);
|
|
nl = NCP2NEGLIST(ncp);
|
|
mtx_assert(&nl->nl_lock, MA_OWNED);
|
|
MPASS(ns->neg_flag & NEG_HOT);
|
|
TAILQ_REMOVE(&nl->nl_hotlist, ncp, nc_dst);
|
|
TAILQ_INSERT_TAIL(&nl->nl_list, ncp, nc_dst);
|
|
nl->nl_hotnum--;
|
|
ns->neg_flag &= ~NEG_HOT;
|
|
atomic_store_char(&ns->neg_hit, 0);
|
|
}
|
|
|
|
/*
|
|
* Move a negative entry to the hot list if it matches the lookup.
|
|
*
|
|
* We have to take locks, but they may be contended and in the worst
|
|
* case we may need to go off CPU. We don't want to spin within the
|
|
* smr section and we can't block with it. Exiting the section means
|
|
* the found entry could have been evicted. We are going to look it
|
|
* up again.
|
|
*/
|
|
static bool
|
|
cache_neg_promote_cond(struct vnode *dvp, struct componentname *cnp,
|
|
struct namecache *oncp, uint32_t hash)
|
|
{
|
|
struct namecache *ncp;
|
|
struct neglist *nl;
|
|
u_char nc_flag;
|
|
|
|
nl = NCP2NEGLIST(oncp);
|
|
|
|
mtx_lock(&nl->nl_lock);
|
|
/*
|
|
* For hash iteration.
|
|
*/
|
|
vfs_smr_enter();
|
|
|
|
/*
|
|
* Avoid all surprises by only succeeding if we got the same entry and
|
|
* bailing completely otherwise.
|
|
* XXX There are no provisions to keep the vnode around, meaning we may
|
|
* end up promoting a negative entry for a *new* vnode and returning
|
|
* ENOENT on its account. This is the error we want to return anyway
|
|
* and promotion is harmless.
|
|
*
|
|
* In particular at this point there can be a new ncp which matches the
|
|
* search but hashes to a different neglist.
|
|
*/
|
|
CK_SLIST_FOREACH(ncp, (NCHHASH(hash)), nc_hash) {
|
|
if (ncp == oncp)
|
|
break;
|
|
}
|
|
|
|
/*
|
|
* No match to begin with.
|
|
*/
|
|
if (__predict_false(ncp == NULL)) {
|
|
goto out_abort;
|
|
}
|
|
|
|
/*
|
|
* The newly found entry may be something different...
|
|
*/
|
|
if (!(ncp->nc_dvp == dvp && ncp->nc_nlen == cnp->cn_namelen &&
|
|
!bcmp(ncp->nc_name, cnp->cn_nameptr, ncp->nc_nlen))) {
|
|
goto out_abort;
|
|
}
|
|
|
|
/*
|
|
* ... and not even negative.
|
|
*/
|
|
nc_flag = atomic_load_char(&ncp->nc_flag);
|
|
if ((nc_flag & NCF_NEGATIVE) == 0) {
|
|
goto out_abort;
|
|
}
|
|
|
|
if (!cache_ncp_canuse(ncp)) {
|
|
goto out_abort;
|
|
}
|
|
|
|
cache_neg_promote_locked(ncp);
|
|
cache_neg_hit_finish(ncp);
|
|
vfs_smr_exit();
|
|
mtx_unlock(&nl->nl_lock);
|
|
return (true);
|
|
out_abort:
|
|
vfs_smr_exit();
|
|
mtx_unlock(&nl->nl_lock);
|
|
return (false);
|
|
}
|
|
|
|
static void
|
|
cache_neg_promote(struct namecache *ncp)
|
|
{
|
|
struct neglist *nl;
|
|
|
|
nl = NCP2NEGLIST(ncp);
|
|
mtx_lock(&nl->nl_lock);
|
|
cache_neg_promote_locked(ncp);
|
|
mtx_unlock(&nl->nl_lock);
|
|
}
|
|
|
|
static void
|
|
cache_neg_insert(struct namecache *ncp)
|
|
{
|
|
struct neglist *nl;
|
|
|
|
MPASS(ncp->nc_flag & NCF_NEGATIVE);
|
|
cache_assert_bucket_locked(ncp);
|
|
nl = NCP2NEGLIST(ncp);
|
|
mtx_lock(&nl->nl_lock);
|
|
TAILQ_INSERT_TAIL(&nl->nl_list, ncp, nc_dst);
|
|
mtx_unlock(&nl->nl_lock);
|
|
atomic_add_long(&numneg, 1);
|
|
}
|
|
|
|
static void
|
|
cache_neg_remove(struct namecache *ncp)
|
|
{
|
|
struct neglist *nl;
|
|
struct negstate *ns;
|
|
|
|
cache_assert_bucket_locked(ncp);
|
|
nl = NCP2NEGLIST(ncp);
|
|
ns = NCP2NEGSTATE(ncp);
|
|
mtx_lock(&nl->nl_lock);
|
|
if ((ns->neg_flag & NEG_HOT) != 0) {
|
|
TAILQ_REMOVE(&nl->nl_hotlist, ncp, nc_dst);
|
|
nl->nl_hotnum--;
|
|
} else {
|
|
TAILQ_REMOVE(&nl->nl_list, ncp, nc_dst);
|
|
}
|
|
mtx_unlock(&nl->nl_lock);
|
|
atomic_subtract_long(&numneg, 1);
|
|
}
|
|
|
|
static struct neglist *
|
|
cache_neg_evict_select_list(void)
|
|
{
|
|
struct neglist *nl;
|
|
u_int c;
|
|
|
|
c = atomic_fetchadd_int(&neg_cycle, 1) + 1;
|
|
nl = &neglists[c % numneglists];
|
|
if (!mtx_trylock(&nl->nl_evict_lock)) {
|
|
counter_u64_add(neg_evict_skipped_contended, 1);
|
|
return (NULL);
|
|
}
|
|
return (nl);
|
|
}
|
|
|
|
static struct namecache *
|
|
cache_neg_evict_select_entry(struct neglist *nl)
|
|
{
|
|
struct namecache *ncp, *lncp;
|
|
struct negstate *ns, *lns;
|
|
int i;
|
|
|
|
mtx_assert(&nl->nl_evict_lock, MA_OWNED);
|
|
mtx_assert(&nl->nl_lock, MA_OWNED);
|
|
ncp = TAILQ_FIRST(&nl->nl_list);
|
|
if (ncp == NULL)
|
|
return (NULL);
|
|
lncp = ncp;
|
|
lns = NCP2NEGSTATE(lncp);
|
|
for (i = 1; i < 4; i++) {
|
|
ncp = TAILQ_NEXT(ncp, nc_dst);
|
|
if (ncp == NULL)
|
|
break;
|
|
ns = NCP2NEGSTATE(ncp);
|
|
if (ns->neg_hit < lns->neg_hit) {
|
|
lncp = ncp;
|
|
lns = ns;
|
|
}
|
|
}
|
|
return (lncp);
|
|
}
|
|
|
|
static bool
|
|
cache_neg_evict(void)
|
|
{
|
|
struct namecache *ncp, *ncp2;
|
|
struct neglist *nl;
|
|
struct vnode *dvp;
|
|
struct mtx *dvlp;
|
|
struct mtx *blp;
|
|
uint32_t hash;
|
|
u_char nlen;
|
|
bool evicted;
|
|
|
|
nl = cache_neg_evict_select_list();
|
|
if (nl == NULL) {
|
|
return (false);
|
|
}
|
|
|
|
mtx_lock(&nl->nl_lock);
|
|
ncp = TAILQ_FIRST(&nl->nl_hotlist);
|
|
if (ncp != NULL) {
|
|
cache_neg_demote_locked(ncp);
|
|
}
|
|
ncp = cache_neg_evict_select_entry(nl);
|
|
if (ncp == NULL) {
|
|
counter_u64_add(neg_evict_skipped_empty, 1);
|
|
mtx_unlock(&nl->nl_lock);
|
|
mtx_unlock(&nl->nl_evict_lock);
|
|
return (false);
|
|
}
|
|
nlen = ncp->nc_nlen;
|
|
dvp = ncp->nc_dvp;
|
|
hash = cache_get_hash(ncp->nc_name, nlen, dvp);
|
|
dvlp = VP2VNODELOCK(dvp);
|
|
blp = HASH2BUCKETLOCK(hash);
|
|
mtx_unlock(&nl->nl_lock);
|
|
mtx_unlock(&nl->nl_evict_lock);
|
|
mtx_lock(dvlp);
|
|
mtx_lock(blp);
|
|
/*
|
|
* Note that since all locks were dropped above, the entry may be
|
|
* gone or reallocated to be something else.
|
|
*/
|
|
CK_SLIST_FOREACH(ncp2, (NCHHASH(hash)), nc_hash) {
|
|
if (ncp2 == ncp && ncp2->nc_dvp == dvp &&
|
|
ncp2->nc_nlen == nlen && (ncp2->nc_flag & NCF_NEGATIVE) != 0)
|
|
break;
|
|
}
|
|
if (ncp2 == NULL) {
|
|
counter_u64_add(neg_evict_skipped_missed, 1);
|
|
ncp = NULL;
|
|
evicted = false;
|
|
} else {
|
|
MPASS(dvlp == VP2VNODELOCK(ncp->nc_dvp));
|
|
MPASS(blp == NCP2BUCKETLOCK(ncp));
|
|
SDT_PROBE2(vfs, namecache, evict_negative, done, ncp->nc_dvp,
|
|
ncp->nc_name);
|
|
cache_zap_locked(ncp);
|
|
counter_u64_add(neg_evicted, 1);
|
|
evicted = true;
|
|
}
|
|
mtx_unlock(blp);
|
|
mtx_unlock(dvlp);
|
|
if (ncp != NULL)
|
|
cache_free(ncp);
|
|
return (evicted);
|
|
}
|
|
|
|
/*
|
|
* Maybe evict a negative entry to create more room.
|
|
*
|
|
* The ncnegfactor parameter limits what fraction of the total count
|
|
* can comprise of negative entries. However, if the cache is just
|
|
* warming up this leads to excessive evictions. As such, ncnegminpct
|
|
* (recomputed to neg_min) dictates whether the above should be
|
|
* applied.
|
|
*
|
|
* Try evicting if the cache is close to full capacity regardless of
|
|
* other considerations.
|
|
*/
|
|
static bool
|
|
cache_neg_evict_cond(u_long lnumcache)
|
|
{
|
|
u_long lnumneg;
|
|
|
|
if (ncsize - 1000 < lnumcache)
|
|
goto out_evict;
|
|
lnumneg = atomic_load_long(&numneg);
|
|
if (lnumneg < neg_min)
|
|
return (false);
|
|
if (lnumneg * ncnegfactor < lnumcache)
|
|
return (false);
|
|
out_evict:
|
|
return (cache_neg_evict());
|
|
}
|
|
|
|
/*
|
|
* 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)
|
|
{
|
|
struct nchashhead *ncpp;
|
|
|
|
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);
|
|
|
|
cache_ncp_invalidate(ncp);
|
|
|
|
ncpp = NCP2BUCKET(ncp);
|
|
CK_SLIST_REMOVE(ncpp, ncp, namecache, 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) {
|
|
vn_seqc_write_begin_unheld(ncp->nc_vp);
|
|
ncp->nc_vp->v_cache_dd = NULL;
|
|
vn_seqc_write_end(ncp->nc_vp);
|
|
}
|
|
} else {
|
|
SDT_PROBE2(vfs, namecache, zap_negative, done, ncp->nc_dvp,
|
|
ncp->nc_name);
|
|
cache_neg_remove(ncp);
|
|
}
|
|
if (ncp->nc_flag & NCF_ISDOTDOT) {
|
|
if (ncp == ncp->nc_dvp->v_cache_dd) {
|
|
vn_seqc_write_begin_unheld(ncp->nc_dvp);
|
|
ncp->nc_dvp->v_cache_dd = NULL;
|
|
vn_seqc_write_end(ncp->nc_dvp);
|
|
}
|
|
} else {
|
|
LIST_REMOVE(ncp, nc_src);
|
|
if (LIST_EMPTY(&ncp->nc_dvp->v_cache_src)) {
|
|
ncp->nc_flag |= NCF_DVDROP;
|
|
}
|
|
}
|
|
}
|
|
|
|
static void
|
|
cache_zap_negative_locked_vnode_kl(struct namecache *ncp, struct vnode *vp)
|
|
{
|
|
struct mtx *blp;
|
|
|
|
MPASS(ncp->nc_dvp == vp);
|
|
MPASS(ncp->nc_flag & NCF_NEGATIVE);
|
|
cache_assert_vnode_locked(vp);
|
|
|
|
blp = NCP2BUCKETLOCK(ncp);
|
|
mtx_lock(blp);
|
|
cache_zap_locked(ncp);
|
|
mtx_unlock(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 mtx *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;
|
|
}
|
|
}
|
|
mtx_lock(blp);
|
|
cache_zap_locked(ncp);
|
|
mtx_unlock(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);
|
|
}
|
|
|
|
/*
|
|
* 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 mtx *blp)
|
|
{
|
|
struct namecache *rncp;
|
|
|
|
cache_assert_bucket_unlocked(ncp);
|
|
|
|
cache_sort_vnodes(&dvlp, &vlp);
|
|
cache_lock_vnodes(dvlp, vlp);
|
|
mtx_lock(blp);
|
|
CK_SLIST_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);
|
|
mtx_unlock(blp);
|
|
cache_unlock_vnodes(dvlp, vlp);
|
|
counter_u64_add(zap_bucket_relock_success, 1);
|
|
return (0);
|
|
}
|
|
|
|
mtx_unlock(blp);
|
|
cache_unlock_vnodes(dvlp, vlp);
|
|
return (EAGAIN);
|
|
}
|
|
|
|
static int __noinline
|
|
cache_zap_locked_bucket(struct namecache *ncp, struct componentname *cnp,
|
|
uint32_t hash, struct mtx *blp)
|
|
{
|
|
struct mtx *dvlp, *vlp;
|
|
struct vnode *dvp;
|
|
|
|
cache_assert_bucket_locked(ncp);
|
|
|
|
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);
|
|
mtx_unlock(blp);
|
|
cache_unlock_vnodes(dvlp, vlp);
|
|
return (0);
|
|
}
|
|
|
|
dvp = ncp->nc_dvp;
|
|
mtx_unlock(blp);
|
|
return (cache_zap_unlocked_bucket(ncp, cnp, dvp, dvlp, vlp, hash, blp));
|
|
}
|
|
|
|
static __noinline int
|
|
cache_remove_cnp(struct vnode *dvp, struct componentname *cnp)
|
|
{
|
|
struct namecache *ncp;
|
|
struct mtx *blp;
|
|
struct mtx *dvlp, *dvlp2;
|
|
uint32_t hash;
|
|
int error;
|
|
|
|
if (cnp->cn_namelen == 2 &&
|
|
cnp->cn_nameptr[0] == '.' && cnp->cn_nameptr[1] == '.') {
|
|
dvlp = VP2VNODELOCK(dvp);
|
|
dvlp2 = NULL;
|
|
mtx_lock(dvlp);
|
|
retry_dotdot:
|
|
ncp = dvp->v_cache_dd;
|
|
if (ncp == NULL) {
|
|
mtx_unlock(dvlp);
|
|
if (dvlp2 != NULL)
|
|
mtx_unlock(dvlp2);
|
|
SDT_PROBE2(vfs, namecache, removecnp, miss, dvp, cnp);
|
|
return (0);
|
|
}
|
|
if ((ncp->nc_flag & NCF_ISDOTDOT) != 0) {
|
|
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 {
|
|
vn_seqc_write_begin(dvp);
|
|
dvp->v_cache_dd = NULL;
|
|
vn_seqc_write_end(dvp);
|
|
mtx_unlock(dvlp);
|
|
if (dvlp2 != NULL)
|
|
mtx_unlock(dvlp2);
|
|
}
|
|
SDT_PROBE2(vfs, namecache, removecnp, hit, dvp, cnp);
|
|
return (1);
|
|
}
|
|
|
|
hash = cache_get_hash(cnp->cn_nameptr, cnp->cn_namelen, dvp);
|
|
blp = HASH2BUCKETLOCK(hash);
|
|
retry:
|
|
if (CK_SLIST_EMPTY(NCHHASH(hash)))
|
|
goto out_no_entry;
|
|
|
|
mtx_lock(blp);
|
|
|
|
CK_SLIST_FOREACH(ncp, (NCHHASH(hash)), nc_hash) {
|
|
if (ncp->nc_dvp == dvp && ncp->nc_nlen == cnp->cn_namelen &&
|
|
!bcmp(ncp->nc_name, cnp->cn_nameptr, ncp->nc_nlen))
|
|
break;
|
|
}
|
|
|
|
if (ncp == NULL) {
|
|
mtx_unlock(blp);
|
|
goto out_no_entry;
|
|
}
|
|
|
|
error = cache_zap_locked_bucket(ncp, cnp, hash, blp);
|
|
if (__predict_false(error != 0)) {
|
|
zap_bucket_fail++;
|
|
goto retry;
|
|
}
|
|
counter_u64_add(numposzaps, 1);
|
|
SDT_PROBE2(vfs, namecache, removecnp, hit, dvp, cnp);
|
|
cache_free(ncp);
|
|
return (1);
|
|
out_no_entry:
|
|
counter_u64_add(nummisszap, 1);
|
|
SDT_PROBE2(vfs, namecache, removecnp, miss, dvp, cnp);
|
|
return (0);
|
|
}
|
|
|
|
static int __noinline
|
|
cache_lookup_dot(struct vnode *dvp, struct vnode **vpp, struct componentname *cnp,
|
|
struct timespec *tsp, int *ticksp)
|
|
{
|
|
int ltype;
|
|
|
|
*vpp = dvp;
|
|
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 int __noinline
|
|
cache_lookup_dotdot(struct vnode *dvp, struct vnode **vpp, struct componentname *cnp,
|
|
struct timespec *tsp, int *ticksp)
|
|
{
|
|
struct namecache_ts *ncp_ts;
|
|
struct namecache *ncp;
|
|
struct mtx *dvlp;
|
|
enum vgetstate vs;
|
|
int error, ltype;
|
|
bool whiteout;
|
|
|
|
MPASS((cnp->cn_flags & ISDOTDOT) != 0);
|
|
|
|
if ((cnp->cn_flags & MAKEENTRY) == 0) {
|
|
cache_remove_cnp(dvp, cnp);
|
|
return (0);
|
|
}
|
|
|
|
counter_u64_add(dotdothits, 1);
|
|
retry:
|
|
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;
|
|
if (*vpp == NULL)
|
|
goto negative_success;
|
|
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;
|
|
}
|
|
|
|
MPASS(dvp != *vpp);
|
|
ltype = VOP_ISLOCKED(dvp);
|
|
VOP_UNLOCK(dvp);
|
|
vs = vget_prep(*vpp);
|
|
mtx_unlock(dvlp);
|
|
error = vget_finish(*vpp, cnp->cn_lkflags, vs);
|
|
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;
|
|
}
|
|
return (-1);
|
|
negative_success:
|
|
if (__predict_false(cnp->cn_nameiop == CREATE)) {
|
|
if (cnp->cn_flags & ISLASTCN) {
|
|
counter_u64_add(numnegzaps, 1);
|
|
cache_zap_negative_locked_vnode_kl(ncp, dvp);
|
|
mtx_unlock(dvlp);
|
|
cache_free(ncp);
|
|
return (0);
|
|
}
|
|
}
|
|
|
|
whiteout = (ncp->nc_flag & NCF_WHITE);
|
|
cache_out_ts(ncp, tsp, ticksp);
|
|
if (cache_neg_hit_prep(ncp))
|
|
cache_neg_promote(ncp);
|
|
else
|
|
cache_neg_hit_finish(ncp);
|
|
mtx_unlock(dvlp);
|
|
if (whiteout)
|
|
cnp->cn_flags |= ISWHITEOUT;
|
|
return (ENOENT);
|
|
}
|
|
|
|
/**
|
|
* 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 ".".
|
|
*
|
|
* Either both tsp and ticks have to be provided or neither of them.
|
|
*
|
|
* # 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.
|
|
*/
|
|
static int __noinline
|
|
cache_lookup_fallback(struct vnode *dvp, struct vnode **vpp, struct componentname *cnp,
|
|
struct timespec *tsp, int *ticksp)
|
|
{
|
|
struct namecache *ncp;
|
|
struct mtx *blp;
|
|
uint32_t hash;
|
|
enum vgetstate vs;
|
|
int error;
|
|
bool whiteout;
|
|
|
|
MPASS((cnp->cn_flags & ISDOTDOT) == 0);
|
|
MPASS((cnp->cn_flags & (MAKEENTRY | NC_KEEPPOSENTRY)) != 0);
|
|
|
|
retry:
|
|
hash = cache_get_hash(cnp->cn_nameptr, cnp->cn_namelen, dvp);
|
|
blp = HASH2BUCKETLOCK(hash);
|
|
mtx_lock(blp);
|
|
|
|
CK_SLIST_FOREACH(ncp, (NCHHASH(hash)), nc_hash) {
|
|
if (ncp->nc_dvp == dvp && ncp->nc_nlen == cnp->cn_namelen &&
|
|
!bcmp(ncp->nc_name, cnp->cn_nameptr, ncp->nc_nlen))
|
|
break;
|
|
}
|
|
|
|
if (__predict_false(ncp == NULL)) {
|
|
mtx_unlock(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;
|
|
|
|
counter_u64_add(numposhits, 1);
|
|
*vpp = ncp->nc_vp;
|
|
SDT_PROBE3(vfs, namecache, lookup, hit, dvp, ncp->nc_name, *vpp);
|
|
cache_out_ts(ncp, tsp, ticksp);
|
|
MPASS(dvp != *vpp);
|
|
vs = vget_prep(*vpp);
|
|
mtx_unlock(blp);
|
|
error = vget_finish(*vpp, cnp->cn_lkflags, vs);
|
|
if (error) {
|
|
*vpp = NULL;
|
|
goto retry;
|
|
}
|
|
return (-1);
|
|
negative_success:
|
|
/*
|
|
* We don't get here with regular lookup apart from corner cases.
|
|
*/
|
|
if (__predict_true(cnp->cn_nameiop == CREATE)) {
|
|
if (cnp->cn_flags & ISLASTCN) {
|
|
counter_u64_add(numnegzaps, 1);
|
|
error = cache_zap_locked_bucket(ncp, cnp, hash, blp);
|
|
if (__predict_false(error != 0)) {
|
|
zap_bucket_fail2++;
|
|
goto retry;
|
|
}
|
|
cache_free(ncp);
|
|
return (0);
|
|
}
|
|
}
|
|
|
|
whiteout = (ncp->nc_flag & NCF_WHITE);
|
|
cache_out_ts(ncp, tsp, ticksp);
|
|
if (cache_neg_hit_prep(ncp))
|
|
cache_neg_promote(ncp);
|
|
else
|
|
cache_neg_hit_finish(ncp);
|
|
mtx_unlock(blp);
|
|
if (whiteout)
|
|
cnp->cn_flags |= ISWHITEOUT;
|
|
return (ENOENT);
|
|
}
|
|
|
|
int
|
|
cache_lookup(struct vnode *dvp, struct vnode **vpp, struct componentname *cnp,
|
|
struct timespec *tsp, int *ticksp)
|
|
{
|
|
struct namecache *ncp;
|
|
uint32_t hash;
|
|
enum vgetstate vs;
|
|
int error;
|
|
bool whiteout, neg_promote;
|
|
u_short nc_flag;
|
|
|
|
MPASS((tsp == NULL && ticksp == NULL) || (tsp != NULL && ticksp != NULL));
|
|
|
|
#ifdef DEBUG_CACHE
|
|
if (__predict_false(!doingcache)) {
|
|
cnp->cn_flags &= ~MAKEENTRY;
|
|
return (0);
|
|
}
|
|
#endif
|
|
|
|
if (__predict_false(cnp->cn_nameptr[0] == '.')) {
|
|
if (cnp->cn_namelen == 1)
|
|
return (cache_lookup_dot(dvp, vpp, cnp, tsp, ticksp));
|
|
if (cnp->cn_namelen == 2 && cnp->cn_nameptr[1] == '.')
|
|
return (cache_lookup_dotdot(dvp, vpp, cnp, tsp, ticksp));
|
|
}
|
|
|
|
MPASS((cnp->cn_flags & ISDOTDOT) == 0);
|
|
|
|
if ((cnp->cn_flags & (MAKEENTRY | NC_KEEPPOSENTRY)) == 0) {
|
|
cache_remove_cnp(dvp, cnp);
|
|
return (0);
|
|
}
|
|
|
|
hash = cache_get_hash(cnp->cn_nameptr, cnp->cn_namelen, dvp);
|
|
vfs_smr_enter();
|
|
|
|
CK_SLIST_FOREACH(ncp, (NCHHASH(hash)), nc_hash) {
|
|
if (ncp->nc_dvp == dvp && ncp->nc_nlen == cnp->cn_namelen &&
|
|
!bcmp(ncp->nc_name, cnp->cn_nameptr, ncp->nc_nlen))
|
|
break;
|
|
}
|
|
|
|
if (__predict_false(ncp == NULL)) {
|
|
vfs_smr_exit();
|
|
SDT_PROBE3(vfs, namecache, lookup, miss, dvp, cnp->cn_nameptr,
|
|
NULL);
|
|
counter_u64_add(nummiss, 1);
|
|
return (0);
|
|
}
|
|
|
|
nc_flag = atomic_load_char(&ncp->nc_flag);
|
|
if (nc_flag & NCF_NEGATIVE)
|
|
goto negative_success;
|
|
|
|
counter_u64_add(numposhits, 1);
|
|
*vpp = ncp->nc_vp;
|
|
SDT_PROBE3(vfs, namecache, lookup, hit, dvp, ncp->nc_name, *vpp);
|
|
cache_out_ts(ncp, tsp, ticksp);
|
|
MPASS(dvp != *vpp);
|
|
if (!cache_ncp_canuse(ncp)) {
|
|
vfs_smr_exit();
|
|
*vpp = NULL;
|
|
goto out_fallback;
|
|
}
|
|
vs = vget_prep_smr(*vpp);
|
|
vfs_smr_exit();
|
|
if (__predict_false(vs == VGET_NONE)) {
|
|
*vpp = NULL;
|
|
goto out_fallback;
|
|
}
|
|
error = vget_finish(*vpp, cnp->cn_lkflags, vs);
|
|
if (error) {
|
|
*vpp = NULL;
|
|
goto out_fallback;
|
|
}
|
|
return (-1);
|
|
negative_success:
|
|
if (cnp->cn_nameiop == CREATE) {
|
|
if (cnp->cn_flags & ISLASTCN) {
|
|
vfs_smr_exit();
|
|
goto out_fallback;
|
|
}
|
|
}
|
|
|
|
cache_out_ts(ncp, tsp, ticksp);
|
|
whiteout = (ncp->nc_flag & NCF_WHITE);
|
|
neg_promote = cache_neg_hit_prep(ncp);
|
|
if (!cache_ncp_canuse(ncp)) {
|
|
cache_neg_hit_abort(ncp);
|
|
vfs_smr_exit();
|
|
goto out_fallback;
|
|
}
|
|
if (neg_promote) {
|
|
vfs_smr_exit();
|
|
if (!cache_neg_promote_cond(dvp, cnp, ncp, hash))
|
|
goto out_fallback;
|
|
} else {
|
|
cache_neg_hit_finish(ncp);
|
|
vfs_smr_exit();
|
|
}
|
|
if (whiteout)
|
|
cnp->cn_flags |= ISWHITEOUT;
|
|
return (ENOENT);
|
|
out_fallback:
|
|
return (cache_lookup_fallback(dvp, vpp, cnp, tsp, ticksp));
|
|
}
|
|
|
|
struct celockstate {
|
|
struct mtx *vlp[3];
|
|
struct mtx *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 mtx *blp1,
|
|
struct mtx *blp2)
|
|
{
|
|
|
|
MPASS(cel->blp[0] == NULL);
|
|
MPASS(cel->blp[1] == NULL);
|
|
|
|
cache_sort_vnodes(&blp1, &blp2);
|
|
|
|
if (blp1 != NULL) {
|
|
mtx_lock(blp1);
|
|
cel->blp[0] = blp1;
|
|
}
|
|
mtx_lock(blp2);
|
|
cel->blp[1] = blp2;
|
|
}
|
|
|
|
static void
|
|
cache_unlock_buckets_cel(struct celockstate *cel)
|
|
{
|
|
|
|
if (cel->blp[0] != NULL)
|
|
mtx_unlock(cel->blp[0]);
|
|
mtx_unlock(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.
|
|
*
|
|
* 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 mtx *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 mtx *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);
|
|
vn_seqc_write_begin(dvp);
|
|
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;
|
|
vn_seqc_write_end(dvp);
|
|
cache_enter_unlock(&cel);
|
|
if (ncp != NULL)
|
|
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;
|
|
struct nchashhead *ncpp;
|
|
uint32_t hash;
|
|
int flag;
|
|
int len;
|
|
|
|
KASSERT(cnp->cn_namelen <= NAME_MAX,
|
|
("%s: passed len %ld exceeds NAME_MAX (%d)", __func__, cnp->cn_namelen,
|
|
NAME_MAX));
|
|
VNPASS(dvp != vp, dvp);
|
|
VNPASS(!VN_IS_DOOMED(dvp), dvp);
|
|
VNPASS(dvp->v_type != VNON, dvp);
|
|
if (vp != NULL) {
|
|
VNPASS(!VN_IS_DOOMED(vp), vp);
|
|
VNPASS(vp->v_type != VNON, vp);
|
|
}
|
|
|
|
#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;
|
|
}
|
|
}
|
|
|
|
ncp = cache_alloc(cnp->cn_namelen, tsp != NULL);
|
|
if (ncp == NULL)
|
|
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->nc_flag = flag | NCF_WIP;
|
|
ncp->nc_vp = vp;
|
|
if (vp == NULL)
|
|
cache_neg_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);
|
|
memcpy(ncp->nc_name, cnp->cn_nameptr, len);
|
|
ncp->nc_name[len] = '\0';
|
|
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_SLIST_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)) {
|
|
MPASS(cache_ncp_canuse(n2));
|
|
if ((n2->nc_flag & NCF_NEGATIVE) != 0)
|
|
KASSERT(vp == NULL,
|
|
("%s: found entry pointing to a different vnode (%p != %p)",
|
|
__func__, NULL, vp));
|
|
else
|
|
KASSERT(n2->nc_vp == vp,
|
|
("%s: found entry pointing to a different vnode (%p != %p)",
|
|
__func__, n2->nc_vp, vp));
|
|
/*
|
|
* Entries are supposed to be immutable unless in the
|
|
* process of getting destroyed. Accommodating for
|
|
* changing timestamps is possible but not worth it.
|
|
* This should be harmless in terms of correctness, in
|
|
* the worst case resulting in an earlier expiration.
|
|
* Alternatively, the found entry can be replaced
|
|
* altogether.
|
|
*/
|
|
MPASS((n2->nc_flag & (NCF_TS | NCF_DTS)) == (ncp->nc_flag & (NCF_TS | NCF_DTS)));
|
|
#if 0
|
|
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;
|
|
}
|
|
}
|
|
#endif
|
|
SDT_PROBE3(vfs, namecache, enter, duplicate, dvp, ncp->nc_name,
|
|
vp);
|
|
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));
|
|
vn_seqc_write_begin(dvp);
|
|
dvp->v_cache_dd = ncp;
|
|
vn_seqc_write_end(dvp);
|
|
}
|
|
|
|
if (vp != NULL) {
|
|
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.
|
|
*/
|
|
vn_seqc_write_begin(vp);
|
|
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;
|
|
vn_seqc_write_end(vp);
|
|
} else if (vp->v_type != VDIR) {
|
|
if (vp->v_cache_dd != NULL) {
|
|
vn_seqc_write_begin(vp);
|
|
vp->v_cache_dd = NULL;
|
|
vn_seqc_write_end(vp);
|
|
}
|
|
}
|
|
}
|
|
|
|
if (flag != NCF_ISDOTDOT) {
|
|
if (LIST_EMPTY(&dvp->v_cache_src)) {
|
|
cache_hold_vnode(dvp);
|
|
}
|
|
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_neg_insert(ncp);
|
|
SDT_PROBE2(vfs, namecache, enter_negative, done, dvp,
|
|
ncp->nc_name);
|
|
}
|
|
|
|
/*
|
|
* Insert the new namecache entry into the appropriate chain
|
|
* within the cache entries table.
|
|
*/
|
|
CK_SLIST_INSERT_HEAD(ncpp, ncp, nc_hash);
|
|
|
|
atomic_thread_fence_rel();
|
|
/*
|
|
* Mark the entry as fully constructed.
|
|
* It is immutable past this point until its removal.
|
|
*/
|
|
atomic_store_char(&ncp->nc_flag, ncp->nc_flag & ~NCF_WIP);
|
|
|
|
cache_enter_unlock(&cel);
|
|
if (ndd != NULL)
|
|
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);
|
|
}
|
|
|
|
static struct nchashhead *
|
|
nchinittbl(u_long elements, u_long *hashmask)
|
|
{
|
|
struct nchashhead *hashtbl;
|
|
u_long hashsize, i;
|
|
|
|
hashsize = cache_roundup_2(elements) / 2;
|
|
|
|
hashtbl = malloc((u_long)hashsize * sizeof(*hashtbl), M_VFSCACHE, M_WAITOK);
|
|
for (i = 0; i < hashsize; i++)
|
|
CK_SLIST_INIT(&hashtbl[i]);
|
|
*hashmask = hashsize - 1;
|
|
return (hashtbl);
|
|
}
|
|
|
|
static void
|
|
ncfreetbl(struct nchashhead *hashtbl)
|
|
{
|
|
|
|
free(hashtbl, M_VFSCACHE);
|
|
}
|
|
|
|
/*
|
|
* 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", CACHE_ZONE_SMALL_SIZE,
|
|
NULL, NULL, NULL, NULL, CACHE_ZONE_ALIGNMENT, UMA_ZONE_ZINIT);
|
|
cache_zone_small_ts = uma_zcreate("STS VFS Cache", CACHE_ZONE_SMALL_TS_SIZE,
|
|
NULL, NULL, NULL, NULL, CACHE_ZONE_ALIGNMENT, UMA_ZONE_ZINIT);
|
|
cache_zone_large = uma_zcreate("L VFS Cache", CACHE_ZONE_LARGE_SIZE,
|
|
NULL, NULL, NULL, NULL, CACHE_ZONE_ALIGNMENT, UMA_ZONE_ZINIT);
|
|
cache_zone_large_ts = uma_zcreate("LTS VFS Cache", CACHE_ZONE_LARGE_TS_SIZE,
|
|
NULL, NULL, NULL, NULL, CACHE_ZONE_ALIGNMENT, 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;
|
|
cache_recalc_neg_min(ncnegminpct);
|
|
nchashtbl = nchinittbl(desiredvnodes * 2, &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++)
|
|
mtx_init(&bucketlocks[i], "ncbuc", NULL, MTX_DUPOK | MTX_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);
|
|
|
|
for (i = 0; i < numneglists; i++) {
|
|
mtx_init(&neglists[i].nl_evict_lock, "ncnege", NULL, MTX_DEF);
|
|
mtx_init(&neglists[i].nl_lock, "ncnegl", NULL, MTX_DEF);
|
|
TAILQ_INIT(&neglists[i].nl_list);
|
|
TAILQ_INIT(&neglists[i].nl_hotlist);
|
|
}
|
|
}
|
|
SYSINIT(vfs, SI_SUB_VFS, SI_ORDER_SECOND, nchinit, NULL);
|
|
|
|
void
|
|
cache_vnode_init(struct vnode *vp)
|
|
{
|
|
|
|
LIST_INIT(&vp->v_cache_src);
|
|
TAILQ_INIT(&vp->v_cache_dst);
|
|
vp->v_cache_dd = NULL;
|
|
cache_prehash(vp);
|
|
}
|
|
|
|
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 = nchinittbl(newmaxvnodes, &new_nchash);
|
|
/* If same hash table size, nothing to do */
|
|
if (nchash == new_nchash) {
|
|
ncfreetbl(new_nchashtbl);
|
|
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_SLIST_FIRST(&old_nchashtbl[i])) != NULL) {
|
|
hash = cache_get_hash(ncp->nc_name, ncp->nc_nlen,
|
|
ncp->nc_dvp);
|
|
CK_SLIST_REMOVE(&old_nchashtbl[i], ncp, namecache, nc_hash);
|
|
CK_SLIST_INSERT_HEAD(NCHHASH(hash), ncp, nc_hash);
|
|
}
|
|
}
|
|
ncsize = newncsize;
|
|
cache_recalc_neg_min(ncnegminpct);
|
|
cache_unlock_all_buckets();
|
|
cache_unlock_all_vnodes();
|
|
ncfreetbl(old_nchashtbl);
|
|
}
|
|
|
|
/*
|
|
* Invalidate all entries from and to a particular vnode.
|
|
*/
|
|
static void
|
|
cache_purge_impl(struct vnode *vp)
|
|
{
|
|
struct cache_freebatch batch;
|
|
struct namecache *ncp;
|
|
struct mtx *vlp, *vlp2;
|
|
|
|
TAILQ_INIT(&batch);
|
|
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(&batch, 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(&batch, 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(&batch, ncp, nc_dst);
|
|
}
|
|
KASSERT(vp->v_cache_dd == NULL, ("incomplete purge"));
|
|
mtx_unlock(vlp);
|
|
if (vlp2 != NULL)
|
|
mtx_unlock(vlp2);
|
|
cache_free_batch(&batch);
|
|
}
|
|
|
|
/*
|
|
* Opportunistic check to see if there is anything to do.
|
|
*/
|
|
static bool
|
|
cache_has_entries(struct vnode *vp)
|
|
{
|
|
|
|
if (LIST_EMPTY(&vp->v_cache_src) && TAILQ_EMPTY(&vp->v_cache_dst) &&
|
|
vp->v_cache_dd == NULL)
|
|
return (false);
|
|
return (true);
|
|
}
|
|
|
|
void
|
|
cache_purge(struct vnode *vp)
|
|
{
|
|
|
|
SDT_PROBE1(vfs, namecache, purge, done, vp);
|
|
if (!cache_has_entries(vp))
|
|
return;
|
|
cache_purge_impl(vp);
|
|
}
|
|
|
|
/*
|
|
* Only to be used by vgone.
|
|
*/
|
|
void
|
|
cache_purge_vgone(struct vnode *vp)
|
|
{
|
|
struct mtx *vlp;
|
|
|
|
VNPASS(VN_IS_DOOMED(vp), vp);
|
|
if (cache_has_entries(vp)) {
|
|
cache_purge_impl(vp);
|
|
return;
|
|
}
|
|
|
|
/*
|
|
* Serialize against a potential thread doing cache_purge.
|
|
*/
|
|
vlp = VP2VNODELOCK(vp);
|
|
mtx_wait_unlocked(vlp);
|
|
if (cache_has_entries(vp)) {
|
|
cache_purge_impl(vp);
|
|
return;
|
|
}
|
|
return;
|
|
}
|
|
|
|
/*
|
|
* Invalidate all negative entries for a particular directory vnode.
|
|
*/
|
|
void
|
|
cache_purge_negative(struct vnode *vp)
|
|
{
|
|
struct cache_freebatch batch;
|
|
struct namecache *ncp, *nnp;
|
|
struct mtx *vlp;
|
|
|
|
SDT_PROBE1(vfs, namecache, purge_negative, done, vp);
|
|
if (LIST_EMPTY(&vp->v_cache_src))
|
|
return;
|
|
TAILQ_INIT(&batch);
|
|
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(&batch, ncp, nc_dst);
|
|
}
|
|
mtx_unlock(vlp);
|
|
cache_free_batch(&batch);
|
|
}
|
|
|
|
/*
|
|
* Entry points for modifying VOP operations.
|
|
*/
|
|
void
|
|
cache_vop_rename(struct vnode *fdvp, struct vnode *fvp, struct vnode *tdvp,
|
|
struct vnode *tvp, struct componentname *fcnp, struct componentname *tcnp)
|
|
{
|
|
|
|
ASSERT_VOP_IN_SEQC(fdvp);
|
|
ASSERT_VOP_IN_SEQC(fvp);
|
|
ASSERT_VOP_IN_SEQC(tdvp);
|
|
if (tvp != NULL)
|
|
ASSERT_VOP_IN_SEQC(tvp);
|
|
|
|
cache_purge(fvp);
|
|
if (tvp != NULL) {
|
|
cache_purge(tvp);
|
|
KASSERT(!cache_remove_cnp(tdvp, tcnp),
|
|
("%s: lingering negative entry", __func__));
|
|
} else {
|
|
cache_remove_cnp(tdvp, tcnp);
|
|
}
|
|
}
|
|
|
|
void
|
|
cache_vop_rmdir(struct vnode *dvp, struct vnode *vp)
|
|
{
|
|
|
|
ASSERT_VOP_IN_SEQC(dvp);
|
|
ASSERT_VOP_IN_SEQC(vp);
|
|
cache_purge(vp);
|
|
}
|
|
|
|
#ifdef INVARIANTS
|
|
/*
|
|
* Validate that if an entry exists it matches.
|
|
*/
|
|
void
|
|
cache_validate(struct vnode *dvp, struct vnode *vp, struct componentname *cnp)
|
|
{
|
|
struct namecache *ncp;
|
|
struct mtx *blp;
|
|
uint32_t hash;
|
|
|
|
hash = cache_get_hash(cnp->cn_nameptr, cnp->cn_namelen, dvp);
|
|
if (CK_SLIST_EMPTY(NCHHASH(hash)))
|
|
return;
|
|
blp = HASH2BUCKETLOCK(hash);
|
|
mtx_lock(blp);
|
|
CK_SLIST_FOREACH(ncp, (NCHHASH(hash)), nc_hash) {
|
|
if (ncp->nc_dvp == dvp && ncp->nc_nlen == cnp->cn_namelen &&
|
|
!bcmp(ncp->nc_name, cnp->cn_nameptr, ncp->nc_nlen)) {
|
|
if (ncp->nc_vp != vp)
|
|
panic("%s: mismatch (%p != %p); ncp %p [%s] dvp %p vp %p\n",
|
|
__func__, vp, ncp->nc_vp, ncp, ncp->nc_name, ncp->nc_dvp,
|
|
ncp->nc_vp);
|
|
}
|
|
}
|
|
mtx_unlock(blp);
|
|
}
|
|
#endif
|
|
|
|
/*
|
|
* Flush all entries referencing a particular filesystem.
|
|
*/
|
|
void
|
|
cache_purgevfs(struct mount *mp)
|
|
{
|
|
struct vnode *vp, *mvp;
|
|
|
|
SDT_PROBE1(vfs, namecache, purgevfs, done, mp);
|
|
/*
|
|
* Somewhat wasteful iteration over all vnodes. Would be better to
|
|
* support filtering and avoid the interlock to begin with.
|
|
*/
|
|
MNT_VNODE_FOREACH_ALL(vp, mp, mvp) {
|
|
if (!cache_has_entries(vp)) {
|
|
VI_UNLOCK(vp);
|
|
continue;
|
|
}
|
|
vholdl(vp);
|
|
VI_UNLOCK(vp);
|
|
cache_purge(vp);
|
|
vdrop(vp);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* 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 = uma_zalloc(namei_zone, M_WAITOK);
|
|
error = vn_getcwd(buf, &retbuf, &buflen);
|
|
if (error == 0)
|
|
error = copyout(retbuf, uap->buf, buflen);
|
|
uma_zfree(namei_zone, buf);
|
|
return (error);
|
|
}
|
|
|
|
int
|
|
vn_getcwd(char *buf, char **retbuf, size_t *buflen)
|
|
{
|
|
struct pwd *pwd;
|
|
int error;
|
|
|
|
vfs_smr_enter();
|
|
pwd = pwd_get_smr();
|
|
error = vn_fullpath_any_smr(pwd->pwd_cdir, pwd->pwd_rdir, buf, retbuf,
|
|
buflen, 0);
|
|
VFS_SMR_ASSERT_NOT_ENTERED();
|
|
if (error < 0) {
|
|
pwd = pwd_hold(curthread);
|
|
error = vn_fullpath_any(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(&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 vnode *vp, char **retbuf, char **freebuf)
|
|
{
|
|
struct pwd *pwd;
|
|
char *buf;
|
|
size_t buflen;
|
|
int error;
|
|
|
|
if (__predict_false(vp == NULL))
|
|
return (EINVAL);
|
|
|
|
buflen = MAXPATHLEN;
|
|
buf = malloc(buflen, M_TEMP, M_WAITOK);
|
|
vfs_smr_enter();
|
|
pwd = pwd_get_smr();
|
|
error = vn_fullpath_any_smr(vp, pwd->pwd_rdir, buf, retbuf, &buflen, 0);
|
|
VFS_SMR_ASSERT_NOT_ENTERED();
|
|
if (error < 0) {
|
|
pwd = pwd_hold(curthread);
|
|
error = vn_fullpath_any(vp, pwd->pwd_rdir, buf, retbuf, &buflen);
|
|
pwd_drop(pwd);
|
|
}
|
|
if (error == 0)
|
|
*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 vnode *vp, char **retbuf, char **freebuf)
|
|
{
|
|
char *buf;
|
|
size_t buflen;
|
|
int error;
|
|
|
|
if (__predict_false(vp == NULL))
|
|
return (EINVAL);
|
|
buflen = MAXPATHLEN;
|
|
buf = malloc(buflen, M_TEMP, M_WAITOK);
|
|
vfs_smr_enter();
|
|
error = vn_fullpath_any_smr(vp, rootvnode, buf, retbuf, &buflen, 0);
|
|
VFS_SMR_ASSERT_NOT_ENTERED();
|
|
if (error < 0) {
|
|
error = vn_fullpath_any(vp, rootvnode, buf, retbuf, &buflen);
|
|
}
|
|
if (error == 0)
|
|
*freebuf = buf;
|
|
else
|
|
free(buf, M_TEMP);
|
|
return (error);
|
|
}
|
|
|
|
static struct namecache *
|
|
vn_dd_from_dst(struct vnode *vp)
|
|
{
|
|
struct namecache *ncp;
|
|
|
|
cache_assert_vnode_locked(vp);
|
|
TAILQ_FOREACH(ncp, &vp->v_cache_dst, nc_dst) {
|
|
if ((ncp->nc_flag & NCF_ISDOTDOT) == 0)
|
|
return (ncp);
|
|
}
|
|
return (NULL);
|
|
}
|
|
|
|
int
|
|
vn_vptocnp(struct vnode **vp, char *buf, size_t *buflen)
|
|
{
|
|
struct vnode *dvp;
|
|
struct namecache *ncp;
|
|
struct mtx *vlp;
|
|
int error;
|
|
|
|
vlp = VP2VNODELOCK(*vp);
|
|
mtx_lock(vlp);
|
|
ncp = (*vp)->v_cache_dd;
|
|
if (ncp != NULL && (ncp->nc_flag & NCF_ISDOTDOT) == 0) {
|
|
KASSERT(ncp == vn_dd_from_dst(*vp),
|
|
("%s: mismatch for dd entry (%p != %p)", __func__,
|
|
ncp, vn_dd_from_dst(*vp)));
|
|
} else {
|
|
ncp = vn_dd_from_dst(*vp);
|
|
}
|
|
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, 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 vnode *vp, struct vnode *rdir, char *buf, char **retbuf,
|
|
size_t *len, size_t addend)
|
|
{
|
|
#ifdef KDTRACE_HOOKS
|
|
struct vnode *startvp = vp;
|
|
#endif
|
|
struct vnode *vp1;
|
|
size_t buflen;
|
|
int error;
|
|
bool slash_prefixed;
|
|
|
|
VNPASS(vp->v_type == VDIR || VN_IS_DOOMED(vp), vp);
|
|
VNPASS(vp->v_usecount > 0, vp);
|
|
|
|
buflen = *len;
|
|
|
|
slash_prefixed = true;
|
|
if (addend == 0) {
|
|
MPASS(*len >= 2);
|
|
buflen--;
|
|
buf[buflen] = '\0';
|
|
slash_prefixed = false;
|
|
}
|
|
|
|
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, 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 void __inline
|
|
cache_rev_failed_impl(int *reason, int line)
|
|
{
|
|
|
|
*reason = line;
|
|
}
|
|
#define cache_rev_failed(var) cache_rev_failed_impl((var), __LINE__)
|
|
|
|
static int
|
|
vn_fullpath_any_smr(struct vnode *vp, struct vnode *rdir, char *buf,
|
|
char **retbuf, size_t *buflen, size_t addend)
|
|
{
|
|
#ifdef KDTRACE_HOOKS
|
|
struct vnode *startvp = vp;
|
|
#endif
|
|
struct vnode *tvp;
|
|
struct mount *mp;
|
|
struct namecache *ncp;
|
|
size_t orig_buflen;
|
|
int reason;
|
|
int error;
|
|
#ifdef KDTRACE_HOOKS
|
|
int i;
|
|
#endif
|
|
seqc_t vp_seqc, tvp_seqc;
|
|
u_char nc_flag;
|
|
|
|
VFS_SMR_ASSERT_ENTERED();
|
|
|
|
if (!cache_fast_revlookup) {
|
|
vfs_smr_exit();
|
|
return (-1);
|
|
}
|
|
|
|
orig_buflen = *buflen;
|
|
|
|
if (addend == 0) {
|
|
MPASS(*buflen >= 2);
|
|
*buflen -= 1;
|
|
buf[*buflen] = '\0';
|
|
}
|
|
|
|
if (vp == rdir || vp == rootvnode) {
|
|
if (addend == 0) {
|
|
*buflen -= 1;
|
|
buf[*buflen] = '/';
|
|
}
|
|
goto out_ok;
|
|
}
|
|
|
|
#ifdef KDTRACE_HOOKS
|
|
i = 0;
|
|
#endif
|
|
error = -1;
|
|
ncp = NULL; /* for sdt probe down below */
|
|
vp_seqc = vn_seqc_read_any(vp);
|
|
if (seqc_in_modify(vp_seqc)) {
|
|
cache_rev_failed(&reason);
|
|
goto out_abort;
|
|
}
|
|
|
|
for (;;) {
|
|
#ifdef KDTRACE_HOOKS
|
|
i++;
|
|
#endif
|
|
if ((vp->v_vflag & VV_ROOT) != 0) {
|
|
mp = atomic_load_ptr(&vp->v_mount);
|
|
if (mp == NULL) {
|
|
cache_rev_failed(&reason);
|
|
goto out_abort;
|
|
}
|
|
tvp = atomic_load_ptr(&mp->mnt_vnodecovered);
|
|
tvp_seqc = vn_seqc_read_any(tvp);
|
|
if (seqc_in_modify(tvp_seqc)) {
|
|
cache_rev_failed(&reason);
|
|
goto out_abort;
|
|
}
|
|
if (!vn_seqc_consistent(vp, vp_seqc)) {
|
|
cache_rev_failed(&reason);
|
|
goto out_abort;
|
|
}
|
|
vp = tvp;
|
|
vp_seqc = tvp_seqc;
|
|
continue;
|
|
}
|
|
ncp = atomic_load_ptr(&vp->v_cache_dd);
|
|
if (ncp == NULL) {
|
|
cache_rev_failed(&reason);
|
|
goto out_abort;
|
|
}
|
|
nc_flag = atomic_load_char(&ncp->nc_flag);
|
|
if ((nc_flag & NCF_ISDOTDOT) != 0) {
|
|
cache_rev_failed(&reason);
|
|
goto out_abort;
|
|
}
|
|
if (!cache_ncp_canuse(ncp)) {
|
|
cache_rev_failed(&reason);
|
|
goto out_abort;
|
|
}
|
|
if (ncp->nc_nlen >= *buflen) {
|
|
cache_rev_failed(&reason);
|
|
error = ENOMEM;
|
|
goto out_abort;
|
|
}
|
|
*buflen -= ncp->nc_nlen;
|
|
memcpy(buf + *buflen, ncp->nc_name, ncp->nc_nlen);
|
|
*buflen -= 1;
|
|
buf[*buflen] = '/';
|
|
tvp = ncp->nc_dvp;
|
|
tvp_seqc = vn_seqc_read_any(tvp);
|
|
if (seqc_in_modify(tvp_seqc)) {
|
|
cache_rev_failed(&reason);
|
|
goto out_abort;
|
|
}
|
|
if (!vn_seqc_consistent(vp, vp_seqc)) {
|
|
cache_rev_failed(&reason);
|
|
goto out_abort;
|
|
}
|
|
vp = tvp;
|
|
vp_seqc = tvp_seqc;
|
|
if (vp == rdir || vp == rootvnode)
|
|
break;
|
|
}
|
|
out_ok:
|
|
vfs_smr_exit();
|
|
*retbuf = buf + *buflen;
|
|
*buflen = orig_buflen - *buflen + addend;
|
|
SDT_PROBE2(vfs, namecache, fullpath_smr, hit, startvp, *retbuf);
|
|
return (0);
|
|
|
|
out_abort:
|
|
*buflen = orig_buflen;
|
|
SDT_PROBE4(vfs, namecache, fullpath_smr, miss, startvp, ncp, reason, i);
|
|
vfs_smr_exit();
|
|
return (error);
|
|
}
|
|
|
|
static int
|
|
vn_fullpath_any(struct vnode *vp, struct vnode *rdir, char *buf, char **retbuf,
|
|
size_t *buflen)
|
|
{
|
|
size_t orig_buflen, addend;
|
|
int error;
|
|
|
|
if (*buflen < 2)
|
|
return (EINVAL);
|
|
|
|
orig_buflen = *buflen;
|
|
|
|
vref(vp);
|
|
addend = 0;
|
|
if (vp->v_type != VDIR) {
|
|
*buflen -= 1;
|
|
buf[*buflen] = '\0';
|
|
error = vn_vptocnp(&vp, buf, buflen);
|
|
if (error)
|
|
return (error);
|
|
if (*buflen == 0) {
|
|
vrele(vp);
|
|
return (ENOMEM);
|
|
}
|
|
*buflen -= 1;
|
|
buf[*buflen] = '/';
|
|
addend = orig_buflen - *buflen;
|
|
}
|
|
|
|
return (vn_fullpath_dir(vp, rdir, buf, retbuf, buflen, addend));
|
|
}
|
|
|
|
/*
|
|
* Resolve an arbitrary vnode to a pathname (taking care of hardlinks).
|
|
*
|
|
* Since the namecache does not track hardlinks, 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
|
|
* following 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 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;
|
|
enum vtype type;
|
|
|
|
if (*buflen < 2)
|
|
return (EINVAL);
|
|
if (*buflen > MAXPATHLEN)
|
|
*buflen = MAXPATHLEN;
|
|
|
|
buf = malloc(*buflen, M_TEMP, M_WAITOK);
|
|
|
|
addend = 0;
|
|
vp = ndp->ni_vp;
|
|
/*
|
|
* Check for VBAD to work around the vp_crossmp bug in lookup().
|
|
*
|
|
* For example consider tmpfs on /tmp and realpath /tmp. ni_vp will be
|
|
* set to mount point's root vnode while ni_dvp will be vp_crossmp.
|
|
* If the type is VDIR (like in this very case) we can skip looking
|
|
* at ni_dvp in the first place. However, since vnodes get passed here
|
|
* unlocked the target may transition to doomed state (type == VBAD)
|
|
* before we get to evaluate the condition. If this happens, we will
|
|
* populate part of the buffer and descend to vn_fullpath_dir with
|
|
* vp == vp_crossmp. Prevent the problem by checking for VBAD.
|
|
*
|
|
* This should be atomic_load(&vp->v_type) but it is illegal to take
|
|
* an address of a bit field, even if said field is sized to char.
|
|
* Work around the problem by reading the value into a full-sized enum
|
|
* and then re-reading it with atomic_load which will still prevent
|
|
* the compiler from re-reading down the road.
|
|
*/
|
|
type = vp->v_type;
|
|
type = atomic_load_int(&type);
|
|
if (type == VBAD) {
|
|
error = ENOENT;
|
|
goto out_bad;
|
|
}
|
|
if (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';
|
|
vp = ndp->ni_dvp;
|
|
}
|
|
|
|
vfs_smr_enter();
|
|
pwd = pwd_get_smr();
|
|
error = vn_fullpath_any_smr(vp, pwd->pwd_rdir, buf, retbuf, buflen,
|
|
addend);
|
|
VFS_SMR_ASSERT_NOT_ENTERED();
|
|
if (error < 0) {
|
|
pwd = pwd_hold(curthread);
|
|
vref(vp);
|
|
error = vn_fullpath_dir(vp, pwd->pwd_rdir, buf, retbuf, buflen,
|
|
addend);
|
|
pwd_drop(pwd);
|
|
if (error != 0)
|
|
goto out_bad;
|
|
}
|
|
|
|
*freebuf = buf;
|
|
|
|
return (0);
|
|
out_bad:
|
|
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(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
|
|
|
|
static int cache_fast_lookup = 1;
|
|
static char __read_frequently cache_fast_lookup_enabled = true;
|
|
|
|
#define CACHE_FPL_FAILED -2020
|
|
|
|
void
|
|
cache_fast_lookup_enabled_recalc(void)
|
|
{
|
|
int lookup_flag;
|
|
int mac_on;
|
|
|
|
#ifdef MAC
|
|
mac_on = mac_vnode_check_lookup_enabled();
|
|
#else
|
|
mac_on = 0;
|
|
#endif
|
|
|
|
lookup_flag = atomic_load_int(&cache_fast_lookup);
|
|
if (lookup_flag && !mac_on) {
|
|
atomic_store_char(&cache_fast_lookup_enabled, true);
|
|
} else {
|
|
atomic_store_char(&cache_fast_lookup_enabled, false);
|
|
}
|
|
}
|
|
|
|
static int
|
|
syscal_vfs_cache_fast_lookup(SYSCTL_HANDLER_ARGS)
|
|
{
|
|
int error, old;
|
|
|
|
old = atomic_load_int(&cache_fast_lookup);
|
|
error = sysctl_handle_int(oidp, arg1, arg2, req);
|
|
if (error == 0 && req->newptr && old != atomic_load_int(&cache_fast_lookup))
|
|
cache_fast_lookup_enabled_recalc();
|
|
return (error);
|
|
}
|
|
SYSCTL_PROC(_vfs, OID_AUTO, cache_fast_lookup, CTLTYPE_INT|CTLFLAG_RW|CTLFLAG_MPSAFE,
|
|
&cache_fast_lookup, 0, syscal_vfs_cache_fast_lookup, "IU", "");
|
|
|
|
/*
|
|
* Components of nameidata (or objects it can point to) which may
|
|
* need restoring in case fast path lookup fails.
|
|
*/
|
|
struct nameidata_outer {
|
|
int cn_flags;
|
|
};
|
|
|
|
struct nameidata_saved {
|
|
#ifdef INVARIANTS
|
|
char *cn_nameptr;
|
|
size_t ni_pathlen;
|
|
#endif
|
|
};
|
|
|
|
#ifdef INVARIANTS
|
|
struct cache_fpl_debug {
|
|
size_t ni_pathlen;
|
|
};
|
|
#endif
|
|
|
|
struct cache_fpl {
|
|
struct nameidata *ndp;
|
|
struct componentname *cnp;
|
|
char *nulchar;
|
|
struct pwd **pwd;
|
|
struct vnode *dvp;
|
|
struct vnode *tvp;
|
|
seqc_t dvp_seqc;
|
|
seqc_t tvp_seqc;
|
|
struct nameidata_saved snd;
|
|
struct nameidata_outer snd_outer;
|
|
int line;
|
|
enum cache_fpl_status status:8;
|
|
bool in_smr;
|
|
bool fsearch;
|
|
bool savename;
|
|
#ifdef INVARIANTS
|
|
struct cache_fpl_debug debug;
|
|
#endif
|
|
};
|
|
|
|
static bool cache_fplookup_is_mp(struct cache_fpl *fpl);
|
|
static int cache_fplookup_cross_mount(struct cache_fpl *fpl);
|
|
static int cache_fplookup_partial_setup(struct cache_fpl *fpl);
|
|
static int cache_fplookup_skip_slashes(struct cache_fpl *fpl);
|
|
static void cache_fpl_pathlen_dec(struct cache_fpl *fpl);
|
|
static void cache_fpl_pathlen_inc(struct cache_fpl *fpl);
|
|
static void cache_fpl_pathlen_sub(struct cache_fpl *fpl, size_t n);
|
|
|
|
static void
|
|
cache_fpl_cleanup_cnp(struct componentname *cnp)
|
|
{
|
|
|
|
uma_zfree(namei_zone, cnp->cn_pnbuf);
|
|
#ifdef DIAGNOSTIC
|
|
cnp->cn_pnbuf = NULL;
|
|
cnp->cn_nameptr = NULL;
|
|
#endif
|
|
}
|
|
|
|
static struct vnode *
|
|
cache_fpl_handle_root(struct cache_fpl *fpl)
|
|
{
|
|
struct nameidata *ndp;
|
|
struct componentname *cnp;
|
|
|
|
ndp = fpl->ndp;
|
|
cnp = fpl->cnp;
|
|
|
|
MPASS(*(cnp->cn_nameptr) == '/');
|
|
cnp->cn_nameptr++;
|
|
cache_fpl_pathlen_dec(fpl);
|
|
|
|
if (__predict_false(*(cnp->cn_nameptr) == '/')) {
|
|
do {
|
|
cnp->cn_nameptr++;
|
|
cache_fpl_pathlen_dec(fpl);
|
|
} while (*(cnp->cn_nameptr) == '/');
|
|
}
|
|
|
|
return (ndp->ni_rootdir);
|
|
}
|
|
|
|
static void
|
|
cache_fpl_checkpoint_outer(struct cache_fpl *fpl)
|
|
{
|
|
|
|
fpl->snd_outer.cn_flags = fpl->ndp->ni_cnd.cn_flags;
|
|
}
|
|
|
|
static void
|
|
cache_fpl_checkpoint(struct cache_fpl *fpl)
|
|
{
|
|
|
|
#ifdef INVARIANTS
|
|
fpl->snd.cn_nameptr = fpl->ndp->ni_cnd.cn_nameptr;
|
|
fpl->snd.ni_pathlen = fpl->debug.ni_pathlen;
|
|
#endif
|
|
}
|
|
|
|
static void
|
|
cache_fpl_restore_partial(struct cache_fpl *fpl)
|
|
{
|
|
|
|
fpl->ndp->ni_cnd.cn_flags = fpl->snd_outer.cn_flags;
|
|
#ifdef INVARIANTS
|
|
fpl->debug.ni_pathlen = fpl->snd.ni_pathlen;
|
|
#endif
|
|
}
|
|
|
|
static void
|
|
cache_fpl_restore_abort(struct cache_fpl *fpl)
|
|
{
|
|
|
|
cache_fpl_restore_partial(fpl);
|
|
/*
|
|
* It is 0 on entry by API contract.
|
|
*/
|
|
fpl->ndp->ni_resflags = 0;
|
|
fpl->ndp->ni_cnd.cn_nameptr = fpl->ndp->ni_cnd.cn_pnbuf;
|
|
}
|
|
|
|
#ifdef INVARIANTS
|
|
#define cache_fpl_smr_assert_entered(fpl) ({ \
|
|
struct cache_fpl *_fpl = (fpl); \
|
|
MPASS(_fpl->in_smr == true); \
|
|
VFS_SMR_ASSERT_ENTERED(); \
|
|
})
|
|
#define cache_fpl_smr_assert_not_entered(fpl) ({ \
|
|
struct cache_fpl *_fpl = (fpl); \
|
|
MPASS(_fpl->in_smr == false); \
|
|
VFS_SMR_ASSERT_NOT_ENTERED(); \
|
|
})
|
|
static void
|
|
cache_fpl_assert_status(struct cache_fpl *fpl)
|
|
{
|
|
|
|
switch (fpl->status) {
|
|
case CACHE_FPL_STATUS_UNSET:
|
|
__assert_unreachable();
|
|
break;
|
|
case CACHE_FPL_STATUS_ABORTED:
|
|
case CACHE_FPL_STATUS_PARTIAL:
|
|
case CACHE_FPL_STATUS_HANDLED:
|
|
break;
|
|
}
|
|
}
|
|
#else
|
|
#define cache_fpl_smr_assert_entered(fpl) do { } while (0)
|
|
#define cache_fpl_smr_assert_not_entered(fpl) do { } while (0)
|
|
#define cache_fpl_assert_status(fpl) do { } while (0)
|
|
#endif
|
|
|
|
#define cache_fpl_smr_enter_initial(fpl) ({ \
|
|
struct cache_fpl *_fpl = (fpl); \
|
|
vfs_smr_enter(); \
|
|
_fpl->in_smr = true; \
|
|
})
|
|
|
|
#define cache_fpl_smr_enter(fpl) ({ \
|
|
struct cache_fpl *_fpl = (fpl); \
|
|
MPASS(_fpl->in_smr == false); \
|
|
vfs_smr_enter(); \
|
|
_fpl->in_smr = true; \
|
|
})
|
|
|
|
#define cache_fpl_smr_exit(fpl) ({ \
|
|
struct cache_fpl *_fpl = (fpl); \
|
|
MPASS(_fpl->in_smr == true); \
|
|
vfs_smr_exit(); \
|
|
_fpl->in_smr = false; \
|
|
})
|
|
|
|
static int
|
|
cache_fpl_aborted_early_impl(struct cache_fpl *fpl, int line)
|
|
{
|
|
|
|
if (fpl->status != CACHE_FPL_STATUS_UNSET) {
|
|
KASSERT(fpl->status == CACHE_FPL_STATUS_PARTIAL,
|
|
("%s: converting to abort from %d at %d, set at %d\n",
|
|
__func__, fpl->status, line, fpl->line));
|
|
}
|
|
cache_fpl_smr_assert_not_entered(fpl);
|
|
fpl->status = CACHE_FPL_STATUS_ABORTED;
|
|
fpl->line = line;
|
|
return (CACHE_FPL_FAILED);
|
|
}
|
|
|
|
#define cache_fpl_aborted_early(x) cache_fpl_aborted_early_impl((x), __LINE__)
|
|
|
|
static int __noinline
|
|
cache_fpl_aborted_impl(struct cache_fpl *fpl, int line)
|
|
{
|
|
|
|
if (fpl->status != CACHE_FPL_STATUS_UNSET) {
|
|
KASSERT(fpl->status == CACHE_FPL_STATUS_PARTIAL,
|
|
("%s: converting to abort from %d at %d, set at %d\n",
|
|
__func__, fpl->status, line, fpl->line));
|
|
}
|
|
fpl->status = CACHE_FPL_STATUS_ABORTED;
|
|
fpl->line = line;
|
|
if (fpl->in_smr)
|
|
cache_fpl_smr_exit(fpl);
|
|
cache_fpl_restore_abort(fpl);
|
|
return (CACHE_FPL_FAILED);
|
|
}
|
|
|
|
#define cache_fpl_aborted(x) cache_fpl_aborted_impl((x), __LINE__)
|
|
|
|
static int __noinline
|
|
cache_fpl_partial_impl(struct cache_fpl *fpl, int line)
|
|
{
|
|
|
|
KASSERT(fpl->status == CACHE_FPL_STATUS_UNSET,
|
|
("%s: setting to partial at %d, but already set to %d at %d\n",
|
|
__func__, line, fpl->status, fpl->line));
|
|
cache_fpl_smr_assert_entered(fpl);
|
|
fpl->status = CACHE_FPL_STATUS_PARTIAL;
|
|
fpl->line = line;
|
|
return (cache_fplookup_partial_setup(fpl));
|
|
}
|
|
|
|
#define cache_fpl_partial(x) cache_fpl_partial_impl((x), __LINE__)
|
|
|
|
static int
|
|
cache_fpl_handled_impl(struct cache_fpl *fpl, int line)
|
|
{
|
|
|
|
KASSERT(fpl->status == CACHE_FPL_STATUS_UNSET,
|
|
("%s: setting to handled at %d, but already set to %d at %d\n",
|
|
__func__, line, fpl->status, fpl->line));
|
|
cache_fpl_smr_assert_not_entered(fpl);
|
|
fpl->status = CACHE_FPL_STATUS_HANDLED;
|
|
fpl->line = line;
|
|
return (0);
|
|
}
|
|
|
|
#define cache_fpl_handled(x) cache_fpl_handled_impl((x), __LINE__)
|
|
|
|
static int
|
|
cache_fpl_handled_error_impl(struct cache_fpl *fpl, int error, int line)
|
|
{
|
|
|
|
KASSERT(fpl->status == CACHE_FPL_STATUS_UNSET,
|
|
("%s: setting to handled at %d, but already set to %d at %d\n",
|
|
__func__, line, fpl->status, fpl->line));
|
|
MPASS(error != 0);
|
|
MPASS(error != CACHE_FPL_FAILED);
|
|
cache_fpl_smr_assert_not_entered(fpl);
|
|
fpl->status = CACHE_FPL_STATUS_HANDLED;
|
|
fpl->line = line;
|
|
fpl->dvp = NULL;
|
|
fpl->tvp = NULL;
|
|
fpl->savename = false;
|
|
return (error);
|
|
}
|
|
|
|
#define cache_fpl_handled_error(x, e) cache_fpl_handled_error_impl((x), (e), __LINE__)
|
|
|
|
static bool
|
|
cache_fpl_terminated(struct cache_fpl *fpl)
|
|
{
|
|
|
|
return (fpl->status != CACHE_FPL_STATUS_UNSET);
|
|
}
|
|
|
|
#define CACHE_FPL_SUPPORTED_CN_FLAGS \
|
|
(NC_NOMAKEENTRY | NC_KEEPPOSENTRY | LOCKLEAF | LOCKPARENT | WANTPARENT | \
|
|
FAILIFEXISTS | FOLLOW | LOCKSHARED | SAVENAME | SAVESTART | WILLBEDIR | \
|
|
ISOPEN | NOMACCHECK | AUDITVNODE1 | AUDITVNODE2 | NOCAPCHECK)
|
|
|
|
#define CACHE_FPL_INTERNAL_CN_FLAGS \
|
|
(ISDOTDOT | MAKEENTRY | ISLASTCN)
|
|
|
|
_Static_assert((CACHE_FPL_SUPPORTED_CN_FLAGS & CACHE_FPL_INTERNAL_CN_FLAGS) == 0,
|
|
"supported and internal flags overlap");
|
|
|
|
static bool
|
|
cache_fpl_islastcn(struct nameidata *ndp)
|
|
{
|
|
|
|
return (*ndp->ni_next == 0);
|
|
}
|
|
|
|
static bool
|
|
cache_fpl_isdotdot(struct componentname *cnp)
|
|
{
|
|
|
|
if (cnp->cn_namelen == 2 &&
|
|
cnp->cn_nameptr[1] == '.' && cnp->cn_nameptr[0] == '.')
|
|
return (true);
|
|
return (false);
|
|
}
|
|
|
|
static bool
|
|
cache_can_fplookup(struct cache_fpl *fpl)
|
|
{
|
|
struct nameidata *ndp;
|
|
struct componentname *cnp;
|
|
struct thread *td;
|
|
|
|
ndp = fpl->ndp;
|
|
cnp = fpl->cnp;
|
|
td = cnp->cn_thread;
|
|
|
|
if (!atomic_load_char(&cache_fast_lookup_enabled)) {
|
|
cache_fpl_aborted_early(fpl);
|
|
return (false);
|
|
}
|
|
if ((cnp->cn_flags & ~CACHE_FPL_SUPPORTED_CN_FLAGS) != 0) {
|
|
cache_fpl_aborted_early(fpl);
|
|
return (false);
|
|
}
|
|
if (IN_CAPABILITY_MODE(td)) {
|
|
cache_fpl_aborted_early(fpl);
|
|
return (false);
|
|
}
|
|
if (AUDITING_TD(td)) {
|
|
cache_fpl_aborted_early(fpl);
|
|
return (false);
|
|
}
|
|
if (ndp->ni_startdir != NULL) {
|
|
cache_fpl_aborted_early(fpl);
|
|
return (false);
|
|
}
|
|
return (true);
|
|
}
|
|
|
|
static int
|
|
cache_fplookup_dirfd(struct cache_fpl *fpl, struct vnode **vpp)
|
|
{
|
|
struct nameidata *ndp;
|
|
int error;
|
|
bool fsearch;
|
|
|
|
ndp = fpl->ndp;
|
|
error = fgetvp_lookup_smr(ndp->ni_dirfd, ndp, vpp, &fsearch);
|
|
if (__predict_false(error != 0)) {
|
|
return (cache_fpl_aborted(fpl));
|
|
}
|
|
fpl->fsearch = fsearch;
|
|
return (0);
|
|
}
|
|
|
|
static bool
|
|
cache_fplookup_vnode_supported(struct vnode *vp)
|
|
{
|
|
|
|
return (vp->v_type != VLNK);
|
|
}
|
|
|
|
static int __noinline
|
|
cache_fplookup_negative_promote(struct cache_fpl *fpl, struct namecache *oncp,
|
|
uint32_t hash)
|
|
{
|
|
struct componentname *cnp;
|
|
struct vnode *dvp;
|
|
|
|
cnp = fpl->cnp;
|
|
dvp = fpl->dvp;
|
|
|
|
cache_fpl_smr_exit(fpl);
|
|
if (cache_neg_promote_cond(dvp, cnp, oncp, hash))
|
|
return (cache_fpl_handled_error(fpl, ENOENT));
|
|
else
|
|
return (cache_fpl_aborted(fpl));
|
|
}
|
|
|
|
/*
|
|
* The target vnode is not supported, prepare for the slow path to take over.
|
|
*/
|
|
static int __noinline
|
|
cache_fplookup_partial_setup(struct cache_fpl *fpl)
|
|
{
|
|
struct nameidata *ndp;
|
|
struct componentname *cnp;
|
|
enum vgetstate dvs;
|
|
struct vnode *dvp;
|
|
struct pwd *pwd;
|
|
seqc_t dvp_seqc;
|
|
|
|
ndp = fpl->ndp;
|
|
cnp = fpl->cnp;
|
|
pwd = *(fpl->pwd);
|
|
dvp = fpl->dvp;
|
|
dvp_seqc = fpl->dvp_seqc;
|
|
|
|
if (!pwd_hold_smr(pwd)) {
|
|
return (cache_fpl_aborted(fpl));
|
|
}
|
|
|
|
/*
|
|
* Note that seqc is checked before the vnode is locked, so by
|
|
* the time regular lookup gets to it it may have moved.
|
|
*
|
|
* Ultimately this does not affect correctness, any lookup errors
|
|
* are userspace racing with itself. It is guaranteed that any
|
|
* path which ultimatley gets found could also have been found
|
|
* by regular lookup going all the way in absence of concurrent
|
|
* modifications.
|
|
*/
|
|
dvs = vget_prep_smr(dvp);
|
|
cache_fpl_smr_exit(fpl);
|
|
if (__predict_false(dvs == VGET_NONE)) {
|
|
pwd_drop(pwd);
|
|
return (cache_fpl_aborted(fpl));
|
|
}
|
|
|
|
vget_finish_ref(dvp, dvs);
|
|
if (!vn_seqc_consistent(dvp, dvp_seqc)) {
|
|
vrele(dvp);
|
|
pwd_drop(pwd);
|
|
return (cache_fpl_aborted(fpl));
|
|
}
|
|
|
|
cache_fpl_restore_partial(fpl);
|
|
#ifdef INVARIANTS
|
|
if (cnp->cn_nameptr != fpl->snd.cn_nameptr) {
|
|
panic("%s: cn_nameptr mismatch (%p != %p) full [%s]\n", __func__,
|
|
cnp->cn_nameptr, fpl->snd.cn_nameptr, cnp->cn_pnbuf);
|
|
}
|
|
#endif
|
|
|
|
ndp->ni_startdir = dvp;
|
|
cnp->cn_flags |= MAKEENTRY;
|
|
if (cache_fpl_islastcn(ndp))
|
|
cnp->cn_flags |= ISLASTCN;
|
|
if (cache_fpl_isdotdot(cnp))
|
|
cnp->cn_flags |= ISDOTDOT;
|
|
|
|
/*
|
|
* Skip potential extra slashes parsing did not take care of.
|
|
* cache_fplookup_skip_slashes explains the mechanism.
|
|
*/
|
|
if (__predict_false(*(cnp->cn_nameptr) == '/')) {
|
|
do {
|
|
cnp->cn_nameptr++;
|
|
cache_fpl_pathlen_dec(fpl);
|
|
} while (*(cnp->cn_nameptr) == '/');
|
|
}
|
|
|
|
ndp->ni_pathlen = fpl->nulchar - cnp->cn_nameptr + 1;
|
|
#ifdef INVARIANTS
|
|
if (ndp->ni_pathlen != fpl->debug.ni_pathlen) {
|
|
panic("%s: mismatch (%zu != %zu) nulchar %p nameptr %p [%s] ; full string [%s]\n",
|
|
__func__, ndp->ni_pathlen, fpl->debug.ni_pathlen, fpl->nulchar,
|
|
cnp->cn_nameptr, cnp->cn_nameptr, cnp->cn_pnbuf);
|
|
}
|
|
#endif
|
|
return (0);
|
|
}
|
|
|
|
static int
|
|
cache_fplookup_final_child(struct cache_fpl *fpl, enum vgetstate tvs)
|
|
{
|
|
struct componentname *cnp;
|
|
struct vnode *tvp;
|
|
seqc_t tvp_seqc;
|
|
int error, lkflags;
|
|
|
|
cnp = fpl->cnp;
|
|
tvp = fpl->tvp;
|
|
tvp_seqc = fpl->tvp_seqc;
|
|
|
|
if ((cnp->cn_flags & LOCKLEAF) != 0) {
|
|
lkflags = LK_SHARED;
|
|
if ((cnp->cn_flags & LOCKSHARED) == 0)
|
|
lkflags = LK_EXCLUSIVE;
|
|
error = vget_finish(tvp, lkflags, tvs);
|
|
if (__predict_false(error != 0)) {
|
|
return (cache_fpl_aborted(fpl));
|
|
}
|
|
} else {
|
|
vget_finish_ref(tvp, tvs);
|
|
}
|
|
|
|
if (!vn_seqc_consistent(tvp, tvp_seqc)) {
|
|
if ((cnp->cn_flags & LOCKLEAF) != 0)
|
|
vput(tvp);
|
|
else
|
|
vrele(tvp);
|
|
return (cache_fpl_aborted(fpl));
|
|
}
|
|
|
|
return (cache_fpl_handled(fpl));
|
|
}
|
|
|
|
/*
|
|
* They want to possibly modify the state of the namecache.
|
|
*/
|
|
static int __noinline
|
|
cache_fplookup_final_modifying(struct cache_fpl *fpl)
|
|
{
|
|
struct nameidata *ndp;
|
|
struct componentname *cnp;
|
|
enum vgetstate dvs;
|
|
struct vnode *dvp, *tvp;
|
|
struct mount *mp;
|
|
seqc_t dvp_seqc;
|
|
int error;
|
|
bool docache;
|
|
|
|
ndp = fpl->ndp;
|
|
cnp = fpl->cnp;
|
|
dvp = fpl->dvp;
|
|
dvp_seqc = fpl->dvp_seqc;
|
|
|
|
MPASS(*(cnp->cn_nameptr) != '/');
|
|
MPASS(cache_fpl_islastcn(ndp));
|
|
if ((cnp->cn_flags & LOCKPARENT) == 0)
|
|
MPASS((cnp->cn_flags & WANTPARENT) != 0);
|
|
MPASS((cnp->cn_flags & TRAILINGSLASH) == 0);
|
|
MPASS(cnp->cn_nameiop == CREATE || cnp->cn_nameiop == DELETE ||
|
|
cnp->cn_nameiop == RENAME);
|
|
MPASS((cnp->cn_flags & MAKEENTRY) == 0);
|
|
MPASS((cnp->cn_flags & ISDOTDOT) == 0);
|
|
|
|
docache = (cnp->cn_flags & NOCACHE) ^ NOCACHE;
|
|
if (cnp->cn_nameiop == DELETE || cnp->cn_nameiop == RENAME)
|
|
docache = false;
|
|
|
|
mp = atomic_load_ptr(&dvp->v_mount);
|
|
if (__predict_false(mp == NULL)) {
|
|
return (cache_fpl_aborted(fpl));
|
|
}
|
|
|
|
if (__predict_false(mp->mnt_flag & MNT_RDONLY)) {
|
|
cache_fpl_smr_exit(fpl);
|
|
/*
|
|
* Original code keeps not checking for CREATE which
|
|
* might be a bug. For now let the old lookup decide.
|
|
*/
|
|
if (cnp->cn_nameiop == CREATE) {
|
|
return (cache_fpl_aborted(fpl));
|
|
}
|
|
return (cache_fpl_handled_error(fpl, EROFS));
|
|
}
|
|
|
|
if (fpl->tvp != NULL && (cnp->cn_flags & FAILIFEXISTS) != 0) {
|
|
cache_fpl_smr_exit(fpl);
|
|
return (cache_fpl_handled_error(fpl, EEXIST));
|
|
}
|
|
|
|
/*
|
|
* Secure access to dvp; check cache_fplookup_partial_setup for
|
|
* reasoning.
|
|
*
|
|
* XXX At least UFS requires its lookup routine to be called for
|
|
* the last path component, which leads to some level of complicaton
|
|
* and inefficiency:
|
|
* - the target routine always locks the target vnode, but our caller
|
|
* may not need it locked
|
|
* - some of the VOP machinery asserts that the parent is locked, which
|
|
* once more may be not required
|
|
*
|
|
* TODO: add a flag for filesystems which don't need this.
|
|
*/
|
|
dvs = vget_prep_smr(dvp);
|
|
cache_fpl_smr_exit(fpl);
|
|
if (__predict_false(dvs == VGET_NONE)) {
|
|
return (cache_fpl_aborted(fpl));
|
|
}
|
|
|
|
vget_finish_ref(dvp, dvs);
|
|
if (!vn_seqc_consistent(dvp, dvp_seqc)) {
|
|
vrele(dvp);
|
|
return (cache_fpl_aborted(fpl));
|
|
}
|
|
|
|
error = vn_lock(dvp, LK_EXCLUSIVE);
|
|
if (__predict_false(error != 0)) {
|
|
vrele(dvp);
|
|
return (cache_fpl_aborted(fpl));
|
|
}
|
|
|
|
tvp = NULL;
|
|
cnp->cn_flags |= ISLASTCN;
|
|
if (docache)
|
|
cnp->cn_flags |= MAKEENTRY;
|
|
if (cache_fpl_isdotdot(cnp))
|
|
cnp->cn_flags |= ISDOTDOT;
|
|
cnp->cn_lkflags = LK_EXCLUSIVE;
|
|
error = VOP_LOOKUP(dvp, &tvp, cnp);
|
|
switch (error) {
|
|
case EJUSTRETURN:
|
|
case 0:
|
|
break;
|
|
case ENOTDIR:
|
|
case ENOENT:
|
|
vput(dvp);
|
|
return (cache_fpl_handled_error(fpl, error));
|
|
default:
|
|
vput(dvp);
|
|
return (cache_fpl_aborted(fpl));
|
|
}
|
|
|
|
fpl->tvp = tvp;
|
|
fpl->savename = (cnp->cn_flags & SAVENAME) != 0;
|
|
|
|
if (tvp == NULL) {
|
|
if ((cnp->cn_flags & SAVESTART) != 0) {
|
|
ndp->ni_startdir = dvp;
|
|
vrefact(ndp->ni_startdir);
|
|
cnp->cn_flags |= SAVENAME;
|
|
fpl->savename = true;
|
|
}
|
|
MPASS(error == EJUSTRETURN);
|
|
if ((cnp->cn_flags & LOCKPARENT) == 0) {
|
|
VOP_UNLOCK(dvp);
|
|
}
|
|
return (cache_fpl_handled(fpl));
|
|
}
|
|
|
|
/*
|
|
* There are very hairy corner cases concerning various flag combinations
|
|
* and locking state. In particular here we only hold one lock instead of
|
|
* two.
|
|
*
|
|
* Skip the complexity as it is of no significance for normal workloads.
|
|
*/
|
|
if (__predict_false(tvp == dvp)) {
|
|
vput(dvp);
|
|
vrele(tvp);
|
|
return (cache_fpl_aborted(fpl));
|
|
}
|
|
|
|
/*
|
|
* Check if the target is either a symlink or a mount point.
|
|
* Since we expect this to be the terminal vnode it should
|
|
* almost never be true.
|
|
*/
|
|
if (__predict_false(!cache_fplookup_vnode_supported(tvp) ||
|
|
cache_fplookup_is_mp(fpl))) {
|
|
vput(dvp);
|
|
vput(tvp);
|
|
return (cache_fpl_aborted(fpl));
|
|
}
|
|
|
|
if ((cnp->cn_flags & FAILIFEXISTS) != 0) {
|
|
vput(dvp);
|
|
vput(tvp);
|
|
return (cache_fpl_handled_error(fpl, EEXIST));
|
|
}
|
|
|
|
if ((cnp->cn_flags & LOCKLEAF) == 0) {
|
|
VOP_UNLOCK(tvp);
|
|
}
|
|
|
|
if ((cnp->cn_flags & LOCKPARENT) == 0) {
|
|
VOP_UNLOCK(dvp);
|
|
}
|
|
|
|
if ((cnp->cn_flags & SAVESTART) != 0) {
|
|
ndp->ni_startdir = dvp;
|
|
vrefact(ndp->ni_startdir);
|
|
cnp->cn_flags |= SAVENAME;
|
|
fpl->savename = true;
|
|
}
|
|
|
|
return (cache_fpl_handled(fpl));
|
|
}
|
|
|
|
static int __noinline
|
|
cache_fplookup_modifying(struct cache_fpl *fpl)
|
|
{
|
|
struct nameidata *ndp;
|
|
|
|
ndp = fpl->ndp;
|
|
|
|
if (!cache_fpl_islastcn(ndp)) {
|
|
return (cache_fpl_partial(fpl));
|
|
}
|
|
return (cache_fplookup_final_modifying(fpl));
|
|
}
|
|
|
|
static int __noinline
|
|
cache_fplookup_final_withparent(struct cache_fpl *fpl)
|
|
{
|
|
struct componentname *cnp;
|
|
enum vgetstate dvs, tvs;
|
|
struct vnode *dvp, *tvp;
|
|
seqc_t dvp_seqc;
|
|
int error;
|
|
|
|
cnp = fpl->cnp;
|
|
dvp = fpl->dvp;
|
|
dvp_seqc = fpl->dvp_seqc;
|
|
tvp = fpl->tvp;
|
|
|
|
MPASS((cnp->cn_flags & (LOCKPARENT|WANTPARENT)) != 0);
|
|
|
|
/*
|
|
* This is less efficient than it can be for simplicity.
|
|
*/
|
|
dvs = vget_prep_smr(dvp);
|
|
if (__predict_false(dvs == VGET_NONE)) {
|
|
return (cache_fpl_aborted(fpl));
|
|
}
|
|
tvs = vget_prep_smr(tvp);
|
|
if (__predict_false(tvs == VGET_NONE)) {
|
|
cache_fpl_smr_exit(fpl);
|
|
vget_abort(dvp, dvs);
|
|
return (cache_fpl_aborted(fpl));
|
|
}
|
|
|
|
cache_fpl_smr_exit(fpl);
|
|
|
|
if ((cnp->cn_flags & LOCKPARENT) != 0) {
|
|
error = vget_finish(dvp, LK_EXCLUSIVE, dvs);
|
|
if (__predict_false(error != 0)) {
|
|
vget_abort(tvp, tvs);
|
|
return (cache_fpl_aborted(fpl));
|
|
}
|
|
} else {
|
|
vget_finish_ref(dvp, dvs);
|
|
}
|
|
|
|
if (!vn_seqc_consistent(dvp, dvp_seqc)) {
|
|
vget_abort(tvp, tvs);
|
|
if ((cnp->cn_flags & LOCKPARENT) != 0)
|
|
vput(dvp);
|
|
else
|
|
vrele(dvp);
|
|
return (cache_fpl_aborted(fpl));
|
|
}
|
|
|
|
error = cache_fplookup_final_child(fpl, tvs);
|
|
if (__predict_false(error != 0)) {
|
|
MPASS(fpl->status == CACHE_FPL_STATUS_ABORTED);
|
|
if ((cnp->cn_flags & LOCKPARENT) != 0)
|
|
vput(dvp);
|
|
else
|
|
vrele(dvp);
|
|
return (error);
|
|
}
|
|
|
|
MPASS(fpl->status == CACHE_FPL_STATUS_HANDLED);
|
|
return (0);
|
|
}
|
|
|
|
static int
|
|
cache_fplookup_final(struct cache_fpl *fpl)
|
|
{
|
|
struct componentname *cnp;
|
|
enum vgetstate tvs;
|
|
struct vnode *dvp, *tvp;
|
|
seqc_t dvp_seqc;
|
|
|
|
cnp = fpl->cnp;
|
|
dvp = fpl->dvp;
|
|
dvp_seqc = fpl->dvp_seqc;
|
|
tvp = fpl->tvp;
|
|
|
|
MPASS(*(cnp->cn_nameptr) != '/');
|
|
|
|
if (cnp->cn_nameiop != LOOKUP) {
|
|
return (cache_fplookup_final_modifying(fpl));
|
|
}
|
|
|
|
if ((cnp->cn_flags & (LOCKPARENT|WANTPARENT)) != 0)
|
|
return (cache_fplookup_final_withparent(fpl));
|
|
|
|
tvs = vget_prep_smr(tvp);
|
|
if (__predict_false(tvs == VGET_NONE)) {
|
|
return (cache_fpl_partial(fpl));
|
|
}
|
|
|
|
if (!vn_seqc_consistent(dvp, dvp_seqc)) {
|
|
cache_fpl_smr_exit(fpl);
|
|
vget_abort(tvp, tvs);
|
|
return (cache_fpl_aborted(fpl));
|
|
}
|
|
|
|
cache_fpl_smr_exit(fpl);
|
|
return (cache_fplookup_final_child(fpl, tvs));
|
|
}
|
|
|
|
/*
|
|
* Comment from locked lookup:
|
|
* Check for degenerate name (e.g. / or "") which is a way of talking about a
|
|
* directory, e.g. like "/." or ".".
|
|
*/
|
|
static int __noinline
|
|
cache_fplookup_degenerate(struct cache_fpl *fpl)
|
|
{
|
|
struct componentname *cnp;
|
|
struct vnode *dvp;
|
|
enum vgetstate dvs;
|
|
int error, lkflags;
|
|
|
|
fpl->tvp = fpl->dvp;
|
|
fpl->tvp_seqc = fpl->dvp_seqc;
|
|
|
|
cnp = fpl->cnp;
|
|
dvp = fpl->dvp;
|
|
|
|
if (__predict_false(cnp->cn_nameiop != LOOKUP)) {
|
|
cache_fpl_smr_exit(fpl);
|
|
return (cache_fpl_handled_error(fpl, EISDIR));
|
|
}
|
|
|
|
MPASS((cnp->cn_flags & SAVESTART) == 0);
|
|
|
|
if ((cnp->cn_flags & (LOCKPARENT|WANTPARENT)) != 0) {
|
|
return (cache_fplookup_final_withparent(fpl));
|
|
}
|
|
|
|
dvs = vget_prep_smr(dvp);
|
|
cache_fpl_smr_exit(fpl);
|
|
if (__predict_false(dvs == VGET_NONE)) {
|
|
return (cache_fpl_aborted(fpl));
|
|
}
|
|
|
|
if ((cnp->cn_flags & LOCKLEAF) != 0) {
|
|
lkflags = LK_SHARED;
|
|
if ((cnp->cn_flags & LOCKSHARED) == 0)
|
|
lkflags = LK_EXCLUSIVE;
|
|
error = vget_finish(dvp, lkflags, dvs);
|
|
if (__predict_false(error != 0)) {
|
|
return (cache_fpl_aborted(fpl));
|
|
}
|
|
} else {
|
|
vget_finish_ref(dvp, dvs);
|
|
}
|
|
return (cache_fpl_handled(fpl));
|
|
}
|
|
|
|
static int __noinline
|
|
cache_fplookup_noentry(struct cache_fpl *fpl)
|
|
{
|
|
struct nameidata *ndp;
|
|
struct componentname *cnp;
|
|
enum vgetstate dvs;
|
|
struct vnode *dvp, *tvp;
|
|
seqc_t dvp_seqc;
|
|
int error;
|
|
bool docache;
|
|
|
|
ndp = fpl->ndp;
|
|
cnp = fpl->cnp;
|
|
dvp = fpl->dvp;
|
|
dvp_seqc = fpl->dvp_seqc;
|
|
|
|
MPASS(*(cnp->cn_nameptr) != '/');
|
|
MPASS((cnp->cn_flags & MAKEENTRY) == 0);
|
|
MPASS((cnp->cn_flags & ISDOTDOT) == 0);
|
|
MPASS(!cache_fpl_isdotdot(cnp));
|
|
|
|
/*
|
|
* Hack: delayed name len checking.
|
|
*/
|
|
if (__predict_false(cnp->cn_namelen > NAME_MAX)) {
|
|
cache_fpl_smr_exit(fpl);
|
|
return (cache_fpl_handled_error(fpl, ENAMETOOLONG));
|
|
}
|
|
|
|
if (cnp->cn_nameiop != LOOKUP) {
|
|
fpl->tvp = NULL;
|
|
return (cache_fplookup_modifying(fpl));
|
|
}
|
|
|
|
MPASS((cnp->cn_flags & SAVESTART) == 0);
|
|
|
|
/*
|
|
* Only try to fill in the component if it is the last one,
|
|
* otherwise not only there may be several to handle but the
|
|
* walk may be complicated.
|
|
*/
|
|
if (!cache_fpl_islastcn(ndp)) {
|
|
return (cache_fpl_partial(fpl));
|
|
}
|
|
|
|
/*
|
|
* Secure access to dvp; check cache_fplookup_partial_setup for
|
|
* reasoning.
|
|
*/
|
|
dvs = vget_prep_smr(dvp);
|
|
cache_fpl_smr_exit(fpl);
|
|
if (__predict_false(dvs == VGET_NONE)) {
|
|
return (cache_fpl_aborted(fpl));
|
|
}
|
|
|
|
vget_finish_ref(dvp, dvs);
|
|
if (!vn_seqc_consistent(dvp, dvp_seqc)) {
|
|
vrele(dvp);
|
|
return (cache_fpl_aborted(fpl));
|
|
}
|
|
|
|
error = vn_lock(dvp, LK_SHARED);
|
|
if (__predict_false(error != 0)) {
|
|
vrele(dvp);
|
|
return (cache_fpl_aborted(fpl));
|
|
}
|
|
|
|
tvp = NULL;
|
|
/*
|
|
* TODO: provide variants which don't require locking either vnode.
|
|
*/
|
|
cnp->cn_flags |= ISLASTCN;
|
|
docache = (cnp->cn_flags & NOCACHE) ^ NOCACHE;
|
|
if (docache)
|
|
cnp->cn_flags |= MAKEENTRY;
|
|
cnp->cn_lkflags = LK_SHARED;
|
|
if ((cnp->cn_flags & LOCKSHARED) == 0) {
|
|
cnp->cn_lkflags = LK_EXCLUSIVE;
|
|
}
|
|
error = VOP_LOOKUP(dvp, &tvp, cnp);
|
|
switch (error) {
|
|
case EJUSTRETURN:
|
|
case 0:
|
|
break;
|
|
case ENOTDIR:
|
|
case ENOENT:
|
|
vput(dvp);
|
|
return (cache_fpl_handled_error(fpl, error));
|
|
default:
|
|
vput(dvp);
|
|
return (cache_fpl_aborted(fpl));
|
|
}
|
|
|
|
fpl->tvp = tvp;
|
|
if (!fpl->savename) {
|
|
MPASS((cnp->cn_flags & SAVENAME) == 0);
|
|
}
|
|
|
|
if (tvp == NULL) {
|
|
MPASS(error == EJUSTRETURN);
|
|
if ((cnp->cn_flags & (WANTPARENT | LOCKPARENT)) == 0) {
|
|
vput(dvp);
|
|
} else if ((cnp->cn_flags & LOCKPARENT) == 0) {
|
|
VOP_UNLOCK(dvp);
|
|
}
|
|
return (cache_fpl_handled(fpl));
|
|
}
|
|
|
|
if (__predict_false(!cache_fplookup_vnode_supported(tvp) ||
|
|
cache_fplookup_is_mp(fpl))) {
|
|
vput(dvp);
|
|
vput(tvp);
|
|
return (cache_fpl_aborted(fpl));
|
|
}
|
|
|
|
if ((cnp->cn_flags & LOCKLEAF) == 0) {
|
|
VOP_UNLOCK(tvp);
|
|
}
|
|
|
|
if ((cnp->cn_flags & (WANTPARENT | LOCKPARENT)) == 0) {
|
|
vput(dvp);
|
|
} else if ((cnp->cn_flags & LOCKPARENT) == 0) {
|
|
VOP_UNLOCK(dvp);
|
|
}
|
|
return (cache_fpl_handled(fpl));
|
|
}
|
|
|
|
static int __noinline
|
|
cache_fplookup_dot(struct cache_fpl *fpl)
|
|
{
|
|
int error;
|
|
|
|
MPASS(!seqc_in_modify(fpl->dvp_seqc));
|
|
/*
|
|
* Just re-assign the value. seqc will be checked later for the first
|
|
* non-dot path component in line and/or before deciding to return the
|
|
* vnode.
|
|
*/
|
|
fpl->tvp = fpl->dvp;
|
|
fpl->tvp_seqc = fpl->dvp_seqc;
|
|
if (cache_fplookup_is_mp(fpl)) {
|
|
error = cache_fplookup_cross_mount(fpl);
|
|
if (__predict_false(error != 0)) {
|
|
return (error);
|
|
}
|
|
}
|
|
|
|
counter_u64_add(dothits, 1);
|
|
SDT_PROBE3(vfs, namecache, lookup, hit, fpl->dvp, ".", fpl->dvp);
|
|
return (0);
|
|
}
|
|
|
|
static int __noinline
|
|
cache_fplookup_dotdot(struct cache_fpl *fpl)
|
|
{
|
|
struct nameidata *ndp;
|
|
struct componentname *cnp;
|
|
struct namecache *ncp;
|
|
struct vnode *dvp;
|
|
struct prison *pr;
|
|
u_char nc_flag;
|
|
|
|
ndp = fpl->ndp;
|
|
cnp = fpl->cnp;
|
|
dvp = fpl->dvp;
|
|
|
|
MPASS(cache_fpl_isdotdot(cnp));
|
|
|
|
/*
|
|
* XXX this is racy the same way regular lookup is
|
|
*/
|
|
for (pr = cnp->cn_cred->cr_prison; pr != NULL;
|
|
pr = pr->pr_parent)
|
|
if (dvp == pr->pr_root)
|
|
break;
|
|
|
|
if (dvp == ndp->ni_rootdir ||
|
|
dvp == ndp->ni_topdir ||
|
|
dvp == rootvnode ||
|
|
pr != NULL) {
|
|
fpl->tvp = dvp;
|
|
fpl->tvp_seqc = vn_seqc_read_any(dvp);
|
|
if (seqc_in_modify(fpl->tvp_seqc)) {
|
|
return (cache_fpl_aborted(fpl));
|
|
}
|
|
return (0);
|
|
}
|
|
|
|
if ((dvp->v_vflag & VV_ROOT) != 0) {
|
|
/*
|
|
* TODO
|
|
* The opposite of climb mount is needed here.
|
|
*/
|
|
return (cache_fpl_aborted(fpl));
|
|
}
|
|
|
|
ncp = atomic_load_ptr(&dvp->v_cache_dd);
|
|
if (ncp == NULL) {
|
|
return (cache_fpl_aborted(fpl));
|
|
}
|
|
|
|
nc_flag = atomic_load_char(&ncp->nc_flag);
|
|
if ((nc_flag & NCF_ISDOTDOT) != 0) {
|
|
if ((nc_flag & NCF_NEGATIVE) != 0)
|
|
return (cache_fpl_aborted(fpl));
|
|
fpl->tvp = ncp->nc_vp;
|
|
} else {
|
|
fpl->tvp = ncp->nc_dvp;
|
|
}
|
|
|
|
if (!cache_ncp_canuse(ncp)) {
|
|
return (cache_fpl_aborted(fpl));
|
|
}
|
|
|
|
fpl->tvp_seqc = vn_seqc_read_any(fpl->tvp);
|
|
if (seqc_in_modify(fpl->tvp_seqc)) {
|
|
return (cache_fpl_partial(fpl));
|
|
}
|
|
|
|
counter_u64_add(dotdothits, 1);
|
|
return (0);
|
|
}
|
|
|
|
static int __noinline
|
|
cache_fplookup_neg(struct cache_fpl *fpl, struct namecache *ncp, uint32_t hash)
|
|
{
|
|
u_char nc_flag;
|
|
bool neg_promote;
|
|
|
|
nc_flag = atomic_load_char(&ncp->nc_flag);
|
|
MPASS((nc_flag & NCF_NEGATIVE) != 0);
|
|
/*
|
|
* If they want to create an entry we need to replace this one.
|
|
*/
|
|
if (__predict_false(fpl->cnp->cn_nameiop != LOOKUP)) {
|
|
fpl->tvp = NULL;
|
|
return (cache_fplookup_modifying(fpl));
|
|
}
|
|
neg_promote = cache_neg_hit_prep(ncp);
|
|
if (!cache_fpl_neg_ncp_canuse(ncp)) {
|
|
cache_neg_hit_abort(ncp);
|
|
return (cache_fpl_partial(fpl));
|
|
}
|
|
if (neg_promote) {
|
|
return (cache_fplookup_negative_promote(fpl, ncp, hash));
|
|
}
|
|
cache_neg_hit_finish(ncp);
|
|
cache_fpl_smr_exit(fpl);
|
|
return (cache_fpl_handled_error(fpl, ENOENT));
|
|
}
|
|
|
|
static int
|
|
cache_fplookup_next(struct cache_fpl *fpl)
|
|
{
|
|
struct componentname *cnp;
|
|
struct namecache *ncp;
|
|
struct vnode *dvp, *tvp;
|
|
u_char nc_flag;
|
|
uint32_t hash;
|
|
int error;
|
|
|
|
cnp = fpl->cnp;
|
|
dvp = fpl->dvp;
|
|
|
|
if (__predict_false(cnp->cn_nameptr[0] == '.')) {
|
|
if (cnp->cn_namelen == 1) {
|
|
return (cache_fplookup_dot(fpl));
|
|
}
|
|
if (cnp->cn_namelen == 2 && cnp->cn_nameptr[1] == '.') {
|
|
return (cache_fplookup_dotdot(fpl));
|
|
}
|
|
}
|
|
|
|
MPASS(!cache_fpl_isdotdot(cnp));
|
|
|
|
hash = cache_get_hash(cnp->cn_nameptr, cnp->cn_namelen, dvp);
|
|
|
|
CK_SLIST_FOREACH(ncp, (NCHHASH(hash)), nc_hash) {
|
|
if (ncp->nc_dvp == dvp && ncp->nc_nlen == cnp->cn_namelen &&
|
|
!bcmp(ncp->nc_name, cnp->cn_nameptr, ncp->nc_nlen))
|
|
break;
|
|
}
|
|
|
|
if (__predict_false(ncp == NULL)) {
|
|
if (cnp->cn_nameptr[0] == '/') {
|
|
return (cache_fplookup_skip_slashes(fpl));
|
|
}
|
|
return (cache_fplookup_noentry(fpl));
|
|
}
|
|
|
|
tvp = atomic_load_ptr(&ncp->nc_vp);
|
|
nc_flag = atomic_load_char(&ncp->nc_flag);
|
|
if ((nc_flag & NCF_NEGATIVE) != 0) {
|
|
return (cache_fplookup_neg(fpl, ncp, hash));
|
|
}
|
|
|
|
if (!cache_ncp_canuse(ncp)) {
|
|
return (cache_fpl_partial(fpl));
|
|
}
|
|
|
|
fpl->tvp = tvp;
|
|
fpl->tvp_seqc = vn_seqc_read_any(tvp);
|
|
if (seqc_in_modify(fpl->tvp_seqc)) {
|
|
return (cache_fpl_partial(fpl));
|
|
}
|
|
|
|
if (!cache_fplookup_vnode_supported(tvp)) {
|
|
return (cache_fpl_partial(fpl));
|
|
}
|
|
|
|
if (cache_fplookup_is_mp(fpl)) {
|
|
error = cache_fplookup_cross_mount(fpl);
|
|
if (__predict_false(error != 0)) {
|
|
return (error);
|
|
}
|
|
}
|
|
|
|
counter_u64_add(numposhits, 1);
|
|
SDT_PROBE3(vfs, namecache, lookup, hit, dvp, ncp->nc_name, tvp);
|
|
return (0);
|
|
}
|
|
|
|
static bool
|
|
cache_fplookup_mp_supported(struct mount *mp)
|
|
{
|
|
|
|
MPASS(mp != NULL);
|
|
if ((mp->mnt_kern_flag & MNTK_FPLOOKUP) == 0)
|
|
return (false);
|
|
return (true);
|
|
}
|
|
|
|
/*
|
|
* Walk up the mount stack (if any).
|
|
*
|
|
* Correctness is provided in the following ways:
|
|
* - all vnodes are protected from freeing with SMR
|
|
* - struct mount objects are type stable making them always safe to access
|
|
* - stability of the particular mount is provided by busying it
|
|
* - relationship between the vnode which is mounted on and the mount is
|
|
* verified with the vnode sequence counter after busying
|
|
* - association between root vnode of the mount and the mount is protected
|
|
* by busy
|
|
*
|
|
* From that point on we can read the sequence counter of the root vnode
|
|
* and get the next mount on the stack (if any) using the same protection.
|
|
*
|
|
* By the end of successful walk we are guaranteed the reached state was
|
|
* indeed present at least at some point which matches the regular lookup.
|
|
*/
|
|
static int __noinline
|
|
cache_fplookup_climb_mount(struct cache_fpl *fpl)
|
|
{
|
|
struct mount *mp, *prev_mp;
|
|
struct mount_pcpu *mpcpu, *prev_mpcpu;
|
|
struct vnode *vp;
|
|
seqc_t vp_seqc;
|
|
|
|
vp = fpl->tvp;
|
|
vp_seqc = fpl->tvp_seqc;
|
|
|
|
VNPASS(vp->v_type == VDIR || vp->v_type == VBAD, vp);
|
|
mp = atomic_load_ptr(&vp->v_mountedhere);
|
|
if (__predict_false(mp == NULL)) {
|
|
return (0);
|
|
}
|
|
|
|
prev_mp = NULL;
|
|
for (;;) {
|
|
if (!vfs_op_thread_enter_crit(mp, mpcpu)) {
|
|
if (prev_mp != NULL)
|
|
vfs_op_thread_exit_crit(prev_mp, prev_mpcpu);
|
|
return (cache_fpl_partial(fpl));
|
|
}
|
|
if (prev_mp != NULL)
|
|
vfs_op_thread_exit_crit(prev_mp, prev_mpcpu);
|
|
if (!vn_seqc_consistent(vp, vp_seqc)) {
|
|
vfs_op_thread_exit_crit(mp, mpcpu);
|
|
return (cache_fpl_partial(fpl));
|
|
}
|
|
if (!cache_fplookup_mp_supported(mp)) {
|
|
vfs_op_thread_exit_crit(mp, mpcpu);
|
|
return (cache_fpl_partial(fpl));
|
|
}
|
|
vp = atomic_load_ptr(&mp->mnt_rootvnode);
|
|
if (vp == NULL) {
|
|
vfs_op_thread_exit_crit(mp, mpcpu);
|
|
return (cache_fpl_partial(fpl));
|
|
}
|
|
vp_seqc = vn_seqc_read_any(vp);
|
|
if (seqc_in_modify(vp_seqc)) {
|
|
vfs_op_thread_exit_crit(mp, mpcpu);
|
|
return (cache_fpl_partial(fpl));
|
|
}
|
|
prev_mp = mp;
|
|
prev_mpcpu = mpcpu;
|
|
mp = atomic_load_ptr(&vp->v_mountedhere);
|
|
if (mp == NULL)
|
|
break;
|
|
}
|
|
|
|
vfs_op_thread_exit_crit(prev_mp, prev_mpcpu);
|
|
fpl->tvp = vp;
|
|
fpl->tvp_seqc = vp_seqc;
|
|
return (0);
|
|
}
|
|
|
|
static int __noinline
|
|
cache_fplookup_cross_mount(struct cache_fpl *fpl)
|
|
{
|
|
struct mount *mp;
|
|
struct mount_pcpu *mpcpu;
|
|
struct vnode *vp;
|
|
seqc_t vp_seqc;
|
|
|
|
vp = fpl->tvp;
|
|
vp_seqc = fpl->tvp_seqc;
|
|
|
|
VNPASS(vp->v_type == VDIR || vp->v_type == VBAD, vp);
|
|
mp = atomic_load_ptr(&vp->v_mountedhere);
|
|
if (__predict_false(mp == NULL)) {
|
|
return (0);
|
|
}
|
|
|
|
if (!vfs_op_thread_enter_crit(mp, mpcpu)) {
|
|
return (cache_fpl_partial(fpl));
|
|
}
|
|
if (!vn_seqc_consistent(vp, vp_seqc)) {
|
|
vfs_op_thread_exit_crit(mp, mpcpu);
|
|
return (cache_fpl_partial(fpl));
|
|
}
|
|
if (!cache_fplookup_mp_supported(mp)) {
|
|
vfs_op_thread_exit_crit(mp, mpcpu);
|
|
return (cache_fpl_partial(fpl));
|
|
}
|
|
vp = atomic_load_ptr(&mp->mnt_rootvnode);
|
|
if (__predict_false(vp == NULL)) {
|
|
vfs_op_thread_exit_crit(mp, mpcpu);
|
|
return (cache_fpl_partial(fpl));
|
|
}
|
|
vp_seqc = vn_seqc_read_any(vp);
|
|
vfs_op_thread_exit_crit(mp, mpcpu);
|
|
if (seqc_in_modify(vp_seqc)) {
|
|
return (cache_fpl_partial(fpl));
|
|
}
|
|
mp = atomic_load_ptr(&vp->v_mountedhere);
|
|
if (__predict_false(mp != NULL)) {
|
|
/*
|
|
* There are possibly more mount points on top.
|
|
* Normally this does not happen so for simplicity just start
|
|
* over.
|
|
*/
|
|
return (cache_fplookup_climb_mount(fpl));
|
|
}
|
|
|
|
fpl->tvp = vp;
|
|
fpl->tvp_seqc = vp_seqc;
|
|
return (0);
|
|
}
|
|
|
|
/*
|
|
* Check if a vnode is mounted on.
|
|
*/
|
|
static bool
|
|
cache_fplookup_is_mp(struct cache_fpl *fpl)
|
|
{
|
|
struct vnode *vp;
|
|
|
|
vp = fpl->tvp;
|
|
return ((vn_irflag_read(vp) & VIRF_MOUNTPOINT) != 0);
|
|
}
|
|
|
|
/*
|
|
* Parse the path.
|
|
*
|
|
* The code was originally copy-pasted from regular lookup and despite
|
|
* clean ups leaves performance on the table. Any modifications here
|
|
* must take into account that in case off fallback the resulting
|
|
* nameidata state has to be compatible with the original.
|
|
*/
|
|
|
|
/*
|
|
* Debug ni_pathlen tracking.
|
|
*/
|
|
#ifdef INVARIANTS
|
|
static void
|
|
cache_fpl_pathlen_dec(struct cache_fpl *fpl)
|
|
{
|
|
|
|
cache_fpl_pathlen_sub(fpl, 1);
|
|
}
|
|
|
|
static void
|
|
cache_fpl_pathlen_inc(struct cache_fpl *fpl)
|
|
{
|
|
|
|
fpl->debug.ni_pathlen++;
|
|
}
|
|
|
|
static void
|
|
cache_fpl_pathlen_sub(struct cache_fpl *fpl, size_t n)
|
|
{
|
|
|
|
fpl->debug.ni_pathlen -= n;
|
|
KASSERT(fpl->debug.ni_pathlen <= PATH_MAX,
|
|
("%s: pathlen underflow to %zd\n", __func__, fpl->debug.ni_pathlen));
|
|
}
|
|
#else
|
|
static void __always_inline
|
|
cache_fpl_pathlen_dec(struct cache_fpl *fpl)
|
|
{
|
|
}
|
|
|
|
static void __always_inline
|
|
cache_fpl_pathlen_inc(struct cache_fpl *fpl)
|
|
{
|
|
}
|
|
|
|
static void
|
|
cache_fpl_pathlen_sub(struct cache_fpl *fpl, size_t n)
|
|
{
|
|
}
|
|
#endif
|
|
|
|
static int
|
|
cache_fplookup_preparse(struct cache_fpl *fpl)
|
|
{
|
|
struct nameidata *ndp;
|
|
struct componentname *cnp;
|
|
|
|
ndp = fpl->ndp;
|
|
cnp = fpl->cnp;
|
|
|
|
if (__predict_false(cnp->cn_nameptr[0] == '\0')) {
|
|
return (cache_fplookup_degenerate(fpl));
|
|
}
|
|
|
|
/*
|
|
* By this point the shortest possible pathname is one character + nul
|
|
* terminator, hence 2.
|
|
*/
|
|
KASSERT(fpl->debug.ni_pathlen >= 2, ("%s: pathlen %zu\n", __func__,
|
|
fpl->debug.ni_pathlen));
|
|
KASSERT(&cnp->cn_nameptr[fpl->debug.ni_pathlen - 2] == fpl->nulchar - 1,
|
|
("%s: mismatch on string (%p != %p) [%s]\n", __func__,
|
|
&cnp->cn_nameptr[fpl->debug.ni_pathlen - 2], fpl->nulchar - 1,
|
|
cnp->cn_pnbuf));
|
|
if (__predict_false(*(fpl->nulchar - 1) == '/')) {
|
|
/*
|
|
* TODO
|
|
* Regular lookup performs the following:
|
|
* *ndp->ni_next = '\0';
|
|
* cnp->cn_flags |= TRAILINGSLASH;
|
|
*
|
|
* Which is problematic since it modifies data read
|
|
* from userspace. Then if fast path lookup was to
|
|
* abort we would have to either restore it or convey
|
|
* the flag. Since this is a corner case just ignore
|
|
* it for simplicity.
|
|
*/
|
|
return (cache_fpl_aborted(fpl));
|
|
}
|
|
return (0);
|
|
}
|
|
|
|
static int
|
|
cache_fplookup_parse(struct cache_fpl *fpl)
|
|
{
|
|
struct nameidata *ndp;
|
|
struct componentname *cnp;
|
|
char *cp;
|
|
|
|
ndp = fpl->ndp;
|
|
cnp = fpl->cnp;
|
|
|
|
/*
|
|
* Find the end of this path component, it is either / or nul.
|
|
*
|
|
* Store / as a temporary sentinel so that we only have one character
|
|
* to test for. Pathnames tend to be short so this should not be
|
|
* resulting in cache misses.
|
|
*/
|
|
KASSERT(&cnp->cn_nameptr[fpl->debug.ni_pathlen - 1] == fpl->nulchar,
|
|
("%s: mismatch between pathlen (%zu) and nulchar (%p != %p), string [%s]\n",
|
|
__func__, fpl->debug.ni_pathlen, &cnp->cn_nameptr[fpl->debug.ni_pathlen - 1],
|
|
fpl->nulchar, cnp->cn_pnbuf));
|
|
KASSERT(*fpl->nulchar == '\0',
|
|
("%s: expected nul at %p; string [%s]\n", __func__, fpl->nulchar,
|
|
cnp->cn_pnbuf));
|
|
*fpl->nulchar = '/';
|
|
for (cp = cnp->cn_nameptr; *cp != '/'; cp++) {
|
|
KASSERT(*cp != '\0',
|
|
("%s: encountered unexpected nul; string [%s]\n", __func__,
|
|
cnp->cn_nameptr));
|
|
continue;
|
|
}
|
|
*fpl->nulchar = '\0';
|
|
|
|
cnp->cn_namelen = cp - cnp->cn_nameptr;
|
|
cache_fpl_pathlen_sub(fpl, cnp->cn_namelen);
|
|
/*
|
|
* Hack: we have to check if the found path component's length exceeds
|
|
* NAME_MAX. However, the condition is very rarely true and check can
|
|
* be elided in the common case -- if an entry was found in the cache,
|
|
* then it could not have been too long to begin with.
|
|
*/
|
|
ndp->ni_next = cp;
|
|
|
|
#ifdef INVARIANTS
|
|
/*
|
|
* Code below is only here to assure compatibility with regular lookup.
|
|
* It covers handling of trailing slashles and names like "/", both of
|
|
* which of can be taken care of upfront which lockless lookup does
|
|
* in cache_fplookup_preparse. Regular lookup performs these for each
|
|
* path component.
|
|
*/
|
|
while (*cp == '/' && (cp[1] == '/' || cp[1] == '\0')) {
|
|
cp++;
|
|
if (*cp == '\0') {
|
|
panic("%s: ran into TRAILINGSLASH handling from [%s]\n",
|
|
__func__, cnp->cn_pnbuf);
|
|
}
|
|
}
|
|
|
|
if (cnp->cn_nameptr[0] == '\0') {
|
|
panic("%s: ran into degenerate name from [%s]\n", __func__, cnp->cn_pnbuf);
|
|
}
|
|
#endif
|
|
return (0);
|
|
}
|
|
|
|
static void
|
|
cache_fplookup_parse_advance(struct cache_fpl *fpl)
|
|
{
|
|
struct nameidata *ndp;
|
|
struct componentname *cnp;
|
|
|
|
ndp = fpl->ndp;
|
|
cnp = fpl->cnp;
|
|
|
|
cnp->cn_nameptr = ndp->ni_next;
|
|
KASSERT(*(cnp->cn_nameptr) == '/',
|
|
("%s: should have seen slash at %p ; buf %p [%s]\n", __func__,
|
|
cnp->cn_nameptr, cnp->cn_pnbuf, cnp->cn_pnbuf));
|
|
cnp->cn_nameptr++;
|
|
cache_fpl_pathlen_dec(fpl);
|
|
}
|
|
|
|
/*
|
|
* Skip spurious slashes in a pathname (e.g., "foo///bar") and retry.
|
|
*
|
|
* Lockless lookup tries to elide checking for spurious slashes and should they
|
|
* be present is guaranteed to fail to find an entry. In this case the caller
|
|
* must check if the name starts with a slash and this call routine. It is
|
|
* going to fast forward across the spurious slashes and set the state up for
|
|
* retry.
|
|
*/
|
|
static int __noinline
|
|
cache_fplookup_skip_slashes(struct cache_fpl *fpl)
|
|
{
|
|
struct nameidata *ndp;
|
|
struct componentname *cnp;
|
|
|
|
ndp = fpl->ndp;
|
|
cnp = fpl->cnp;
|
|
|
|
MPASS(*(cnp->cn_nameptr) == '/');
|
|
do {
|
|
cnp->cn_nameptr++;
|
|
cache_fpl_pathlen_dec(fpl);
|
|
} while (*(cnp->cn_nameptr) == '/');
|
|
|
|
/*
|
|
* Go back to one slash so that cache_fplookup_parse_advance has
|
|
* something to skip.
|
|
*/
|
|
cnp->cn_nameptr--;
|
|
cache_fpl_pathlen_inc(fpl);
|
|
|
|
/*
|
|
* cache_fplookup_parse_advance starts from ndp->ni_next
|
|
*/
|
|
ndp->ni_next = cnp->cn_nameptr;
|
|
|
|
/*
|
|
* See cache_fplookup_dot.
|
|
*/
|
|
fpl->tvp = fpl->dvp;
|
|
fpl->tvp_seqc = fpl->dvp_seqc;
|
|
|
|
return (0);
|
|
}
|
|
|
|
/*
|
|
* See the API contract for VOP_FPLOOKUP_VEXEC.
|
|
*/
|
|
static int __noinline
|
|
cache_fplookup_failed_vexec(struct cache_fpl *fpl, int error)
|
|
{
|
|
struct componentname *cnp;
|
|
struct vnode *dvp;
|
|
seqc_t dvp_seqc;
|
|
|
|
cnp = fpl->cnp;
|
|
dvp = fpl->dvp;
|
|
dvp_seqc = fpl->dvp_seqc;
|
|
|
|
/*
|
|
* Hack: delayed name len checking.
|
|
*/
|
|
if (__predict_false(cnp->cn_namelen > NAME_MAX)) {
|
|
cache_fpl_smr_exit(fpl);
|
|
return (cache_fpl_handled_error(fpl, ENAMETOOLONG));
|
|
}
|
|
|
|
/*
|
|
* Hack: they may be looking up foo/bar, where foo is a
|
|
* regular file. In such a case we need to turn ENOTDIR,
|
|
* but we may happen to get here with a different error.
|
|
*/
|
|
if (dvp->v_type != VDIR) {
|
|
/*
|
|
* The check here is predominantly to catch
|
|
* EOPNOTSUPP from dead_vnodeops. If the vnode
|
|
* gets doomed past this point it is going to
|
|
* fail seqc verification.
|
|
*/
|
|
if (VN_IS_DOOMED(dvp)) {
|
|
return (cache_fpl_aborted(fpl));
|
|
}
|
|
error = ENOTDIR;
|
|
}
|
|
|
|
/*
|
|
* Hack: handle O_SEARCH.
|
|
*
|
|
* Open Group Base Specifications Issue 7, 2018 edition states:
|
|
* If the access mode of the open file description associated with the
|
|
* file descriptor is not O_SEARCH, the function shall check whether
|
|
* directory searches are permitted using the current permissions of
|
|
* the directory underlying the file descriptor. If the access mode is
|
|
* O_SEARCH, the function shall not perform the check.
|
|
*
|
|
* Regular lookup tests for the NOEXECCHECK flag for every path
|
|
* component to decide whether to do the permission check. However,
|
|
* since most lookups never have the flag (and when they do it is only
|
|
* present for the first path component), lockless lookup only acts on
|
|
* it if there is a permission problem. Here the flag is represented
|
|
* with a boolean so that we don't have to clear it on the way out.
|
|
*
|
|
* For simplicity this always aborts.
|
|
* TODO: check if this is the first lookup and ignore the permission
|
|
* problem. Note the flag has to survive fallback (if it happens to be
|
|
* performed).
|
|
*/
|
|
if (fpl->fsearch) {
|
|
return (cache_fpl_aborted(fpl));
|
|
}
|
|
|
|
switch (error) {
|
|
case EAGAIN:
|
|
if (!vn_seqc_consistent(dvp, dvp_seqc)) {
|
|
error = cache_fpl_aborted(fpl);
|
|
} else {
|
|
cache_fpl_partial(fpl);
|
|
}
|
|
break;
|
|
default:
|
|
if (!vn_seqc_consistent(dvp, dvp_seqc)) {
|
|
error = cache_fpl_aborted(fpl);
|
|
} else {
|
|
cache_fpl_smr_exit(fpl);
|
|
cache_fpl_handled_error(fpl, error);
|
|
}
|
|
break;
|
|
}
|
|
return (error);
|
|
}
|
|
|
|
static int
|
|
cache_fplookup_impl(struct vnode *dvp, struct cache_fpl *fpl)
|
|
{
|
|
struct nameidata *ndp;
|
|
struct componentname *cnp;
|
|
struct mount *mp;
|
|
int error;
|
|
|
|
ndp = fpl->ndp;
|
|
cnp = fpl->cnp;
|
|
|
|
cache_fpl_checkpoint(fpl);
|
|
|
|
/*
|
|
* The vnode at hand is almost always stable, skip checking for it.
|
|
* Worst case this postpones the check towards the end of the iteration
|
|
* of the main loop.
|
|
*/
|
|
fpl->dvp = dvp;
|
|
fpl->dvp_seqc = vn_seqc_read_notmodify(fpl->dvp);
|
|
|
|
mp = atomic_load_ptr(&dvp->v_mount);
|
|
if (__predict_false(mp == NULL || !cache_fplookup_mp_supported(mp))) {
|
|
return (cache_fpl_aborted(fpl));
|
|
}
|
|
|
|
VNPASS(cache_fplookup_vnode_supported(fpl->dvp), fpl->dvp);
|
|
|
|
error = cache_fplookup_preparse(fpl);
|
|
if (__predict_false(cache_fpl_terminated(fpl))) {
|
|
return (error);
|
|
}
|
|
|
|
for (;;) {
|
|
error = cache_fplookup_parse(fpl);
|
|
if (__predict_false(error != 0)) {
|
|
break;
|
|
}
|
|
|
|
VNPASS(cache_fplookup_vnode_supported(fpl->dvp), fpl->dvp);
|
|
|
|
error = VOP_FPLOOKUP_VEXEC(fpl->dvp, cnp->cn_cred);
|
|
if (__predict_false(error != 0)) {
|
|
error = cache_fplookup_failed_vexec(fpl, error);
|
|
break;
|
|
}
|
|
|
|
error = cache_fplookup_next(fpl);
|
|
if (__predict_false(cache_fpl_terminated(fpl))) {
|
|
break;
|
|
}
|
|
|
|
VNPASS(!seqc_in_modify(fpl->tvp_seqc), fpl->tvp);
|
|
|
|
if (cache_fpl_islastcn(ndp)) {
|
|
error = cache_fplookup_final(fpl);
|
|
break;
|
|
}
|
|
|
|
if (!vn_seqc_consistent(fpl->dvp, fpl->dvp_seqc)) {
|
|
error = cache_fpl_aborted(fpl);
|
|
break;
|
|
}
|
|
|
|
fpl->dvp = fpl->tvp;
|
|
fpl->dvp_seqc = fpl->tvp_seqc;
|
|
|
|
cache_fplookup_parse_advance(fpl);
|
|
cache_fpl_checkpoint(fpl);
|
|
}
|
|
|
|
return (error);
|
|
}
|
|
|
|
/*
|
|
* Fast path lookup protected with SMR and sequence counters.
|
|
*
|
|
* Note: all VOP_FPLOOKUP_VEXEC routines have a comment referencing this one.
|
|
*
|
|
* Filesystems can opt in by setting the MNTK_FPLOOKUP flag and meeting criteria
|
|
* outlined below.
|
|
*
|
|
* Traditional vnode lookup conceptually looks like this:
|
|
*
|
|
* vn_lock(current);
|
|
* for (;;) {
|
|
* next = find();
|
|
* vn_lock(next);
|
|
* vn_unlock(current);
|
|
* current = next;
|
|
* if (last)
|
|
* break;
|
|
* }
|
|
* return (current);
|
|
*
|
|
* Each jump to the next vnode is safe memory-wise and atomic with respect to
|
|
* any modifications thanks to holding respective locks.
|
|
*
|
|
* The same guarantee can be provided with a combination of safe memory
|
|
* reclamation and sequence counters instead. If all operations which affect
|
|
* the relationship between the current vnode and the one we are looking for
|
|
* also modify the counter, we can verify whether all the conditions held as
|
|
* we made the jump. This includes things like permissions, mount points etc.
|
|
* Counter modification is provided by enclosing relevant places in
|
|
* vn_seqc_write_begin()/end() calls.
|
|
*
|
|
* Thus this translates to:
|
|
*
|
|
* vfs_smr_enter();
|
|
* dvp_seqc = seqc_read_any(dvp);
|
|
* if (seqc_in_modify(dvp_seqc)) // someone is altering the vnode
|
|
* abort();
|
|
* for (;;) {
|
|
* tvp = find();
|
|
* tvp_seqc = seqc_read_any(tvp);
|
|
* if (seqc_in_modify(tvp_seqc)) // someone is altering the target vnode
|
|
* abort();
|
|
* if (!seqc_consistent(dvp, dvp_seqc) // someone is altering the vnode
|
|
* abort();
|
|
* dvp = tvp; // we know nothing of importance has changed
|
|
* dvp_seqc = tvp_seqc; // store the counter for the tvp iteration
|
|
* if (last)
|
|
* break;
|
|
* }
|
|
* vget(); // secure the vnode
|
|
* if (!seqc_consistent(tvp, tvp_seqc) // final check
|
|
* abort();
|
|
* // at this point we know nothing has changed for any parent<->child pair
|
|
* // as they were crossed during the lookup, meaning we matched the guarantee
|
|
* // of the locked variant
|
|
* return (tvp);
|
|
*
|
|
* The API contract for VOP_FPLOOKUP_VEXEC routines is as follows:
|
|
* - they are called while within vfs_smr protection which they must never exit
|
|
* - EAGAIN can be returned to denote checking could not be performed, it is
|
|
* always valid to return it
|
|
* - if the sequence counter has not changed the result must be valid
|
|
* - if the sequence counter has changed both false positives and false negatives
|
|
* are permitted (since the result will be rejected later)
|
|
* - for simple cases of unix permission checks vaccess_vexec_smr can be used
|
|
*
|
|
* Caveats to watch out for:
|
|
* - vnodes are passed unlocked and unreferenced with nothing stopping
|
|
* VOP_RECLAIM, in turn meaning that ->v_data can become NULL. It is advised
|
|
* to use atomic_load_ptr to fetch it.
|
|
* - the aforementioned object can also get freed, meaning absent other means it
|
|
* should be protected with vfs_smr
|
|
* - either safely checking permissions as they are modified or guaranteeing
|
|
* their stability is left to the routine
|
|
*/
|
|
int
|
|
cache_fplookup(struct nameidata *ndp, enum cache_fpl_status *status,
|
|
struct pwd **pwdp)
|
|
{
|
|
struct cache_fpl fpl;
|
|
struct pwd *pwd;
|
|
struct vnode *dvp;
|
|
struct componentname *cnp;
|
|
int error;
|
|
|
|
fpl.status = CACHE_FPL_STATUS_UNSET;
|
|
fpl.in_smr = false;
|
|
fpl.ndp = ndp;
|
|
fpl.cnp = cnp = &ndp->ni_cnd;
|
|
MPASS(ndp->ni_lcf == 0);
|
|
MPASS(curthread == cnp->cn_thread);
|
|
KASSERT ((cnp->cn_flags & CACHE_FPL_INTERNAL_CN_FLAGS) == 0,
|
|
("%s: internal flags found in cn_flags %" PRIx64, __func__,
|
|
cnp->cn_flags));
|
|
if ((cnp->cn_flags & SAVESTART) != 0) {
|
|
MPASS(cnp->cn_nameiop != LOOKUP);
|
|
}
|
|
MPASS(cnp->cn_nameptr == cnp->cn_pnbuf);
|
|
|
|
if (__predict_false(!cache_can_fplookup(&fpl))) {
|
|
*status = fpl.status;
|
|
SDT_PROBE3(vfs, fplookup, lookup, done, ndp, fpl.line, fpl.status);
|
|
return (EOPNOTSUPP);
|
|
}
|
|
|
|
cache_fpl_checkpoint_outer(&fpl);
|
|
|
|
cache_fpl_smr_enter_initial(&fpl);
|
|
#ifdef INVARIANTS
|
|
fpl.debug.ni_pathlen = ndp->ni_pathlen;
|
|
#endif
|
|
fpl.nulchar = &cnp->cn_nameptr[ndp->ni_pathlen - 1];
|
|
fpl.fsearch = false;
|
|
fpl.savename = (cnp->cn_flags & SAVENAME) != 0;
|
|
fpl.pwd = pwdp;
|
|
pwd = pwd_get_smr();
|
|
*(fpl.pwd) = pwd;
|
|
ndp->ni_rootdir = pwd->pwd_rdir;
|
|
ndp->ni_topdir = pwd->pwd_jdir;
|
|
|
|
if (cnp->cn_pnbuf[0] == '/') {
|
|
dvp = cache_fpl_handle_root(&fpl);
|
|
ndp->ni_resflags |= NIRES_ABS;
|
|
} else {
|
|
if (ndp->ni_dirfd == AT_FDCWD) {
|
|
dvp = pwd->pwd_cdir;
|
|
} else {
|
|
error = cache_fplookup_dirfd(&fpl, &dvp);
|
|
if (__predict_false(error != 0)) {
|
|
goto out;
|
|
}
|
|
}
|
|
}
|
|
|
|
SDT_PROBE4(vfs, namei, lookup, entry, dvp, cnp->cn_pnbuf, cnp->cn_flags, true);
|
|
error = cache_fplookup_impl(dvp, &fpl);
|
|
out:
|
|
cache_fpl_smr_assert_not_entered(&fpl);
|
|
cache_fpl_assert_status(&fpl);
|
|
*status = fpl.status;
|
|
if (SDT_PROBES_ENABLED()) {
|
|
SDT_PROBE3(vfs, fplookup, lookup, done, ndp, fpl.line, fpl.status);
|
|
if (fpl.status == CACHE_FPL_STATUS_HANDLED)
|
|
SDT_PROBE3(vfs, namei, lookup, return, error, ndp->ni_vp, true);
|
|
}
|
|
|
|
if (__predict_true(fpl.status == CACHE_FPL_STATUS_HANDLED)) {
|
|
MPASS(error != CACHE_FPL_FAILED);
|
|
if (error != 0) {
|
|
MPASS(fpl.dvp == NULL);
|
|
MPASS(fpl.tvp == NULL);
|
|
MPASS(fpl.savename == false);
|
|
}
|
|
ndp->ni_dvp = fpl.dvp;
|
|
ndp->ni_vp = fpl.tvp;
|
|
if (fpl.savename) {
|
|
cnp->cn_flags |= HASBUF;
|
|
} else {
|
|
cache_fpl_cleanup_cnp(cnp);
|
|
}
|
|
}
|
|
return (error);
|
|
}
|