fec4bb5bba
UDF. Future users could be msdosfs, ufs, nilfs2 (when ready), cd9660 etc. Note that its not the same as UFS's DIRHASH support; UFS would need a good cleanup/splitout of directory operations to adopt to this new directory hashing support since most directory operations are interweaved with the vnops itself. This is a TODO.
488 lines
12 KiB
C
488 lines
12 KiB
C
/* $NetBSD: vfs_dirhash.c,v 1.1 2008/09/27 13:01:07 reinoud Exp $ */
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/*
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* Copyright (c) 2008 Reinoud Zandijk
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* All rights reserved.
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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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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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*/
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#include <sys/cdefs.h>
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#ifndef lint
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__KERNEL_RCSID(0, "$NetBSD: vfs_dirhash.c,v 1.1 2008/09/27 13:01:07 reinoud Exp $");
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#endif /* not lint */
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#if 1
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# define DPRINTF(a) ;
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#else
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# define DPRINTF(a) printf(a);
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#endif
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/* CLEAN UP! */
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#include <sys/sysctl.h>
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/sysctl.h>
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#include <sys/namei.h>
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#include <sys/proc.h>
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#include <sys/kernel.h>
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#include <sys/vnode.h>
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#include <sys/mount.h>
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#include <sys/buf.h>
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#include <sys/file.h>
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#include <sys/device.h>
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#include <sys/disklabel.h>
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#include <sys/ioctl.h>
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#include <sys/malloc.h>
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#include <sys/dirent.h>
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#include <sys/stat.h>
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#include <sys/conf.h>
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#include <sys/kauth.h>
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#include <dev/clock_subr.h>
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#include <sys/dirhash.h>
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static struct sysctllog *sysctl_log;
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struct pool dirhash_pool;
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struct pool dirhash_entry_pool;
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kmutex_t dirhashmutex;
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uint32_t maxdirhashsize = DIRHASH_SIZE;
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uint32_t dirhashsize = 0;
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TAILQ_HEAD(_dirhash, dirhash) dirhash_queue;
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#define CURDIRHASHSIZE_SYSCTLOPT 1
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#define MAXDIRHASHSIZE_SYSCTLOPT 2
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void
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dirhash_init(void)
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{
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size_t size;
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uint32_t max_entries;
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/* initialise dirhash queue */
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TAILQ_INIT(&dirhash_queue);
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/* init dirhash pools */
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size = sizeof(struct dirhash);
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pool_init(&dirhash_pool, size, 0, 0, 0,
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"dirhash_pool", NULL, IPL_NONE);
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size = sizeof(struct dirhash_entry);
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pool_init(&dirhash_entry_pool, size, 0, 0, 0,
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"dirhash_entry_pool", NULL, IPL_NONE);
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mutex_init(&dirhashmutex, MUTEX_DEFAULT, IPL_NONE);
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max_entries = maxdirhashsize / size;
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pool_sethiwat(&dirhash_entry_pool, max_entries);
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dirhashsize = 0;
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/* create sysctl knobs and dials */
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sysctl_log = NULL;
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#if 0
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sysctl_createv(&sysctl_log, 0, NULL, &node,
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CTLFLAG_PERMANENT,
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CTLTYPE_NODE, "vfs", NULL,
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NULL, 0, NULL, 0,
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CTL_VFS, CTL_EOL);
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sysctl_createv(&sysctl_log, 0, NULL, &node,
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CTLFLAG_PERMANENT,
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CTLTYPE_INT, "curdirhashsize",
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SYSCTL_DESCR("Current memory to be used by dirhash"),
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NULL, 0, &dirhashsize, 0,
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CTL_VFS, 0, CURDIRHASHSIZE_SYSCTLOPT, CTL_EOL);
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sysctl_createv(&sysctl_log, 0, NULL, &node,
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CTLFLAG_PERMANENT | CTLFLAG_READWRITE,
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CTLTYPE_INT, "maxdirhashsize",
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SYSCTL_DESCR("Max memory to be used by dirhash"),
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NULL, 0, &maxdirhashsize, 0,
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CTL_VFS, 0, MAXDIRHASHSIZE_SYSCTLOPT, CTL_EOL);
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#endif
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}
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#if 0
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void
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dirhash_finish(void)
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{
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pool_destroy(&dirhash_pool);
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pool_destroy(&dirhash_entry_pool);
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mutex_destroy(&dirhashmutex);
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/* sysctl_teardown(&sysctl_log); */
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}
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#endif
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/*
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* generic dirhash implementation
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*/
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static uint32_t
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dirhash_hash(const char *str, int namelen)
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{
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uint32_t hash = 5381;
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int i, c;
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for (i = 0; i < namelen; i++) {
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c = *str++;
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hash = ((hash << 5) + hash) + c; /* hash * 33 + c */
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}
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return hash;
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}
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void
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dirhash_purge_entries(struct dirhash *dirh)
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{
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struct dirhash_entry *dirh_e;
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uint32_t hashline;
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if (dirh == NULL)
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return;
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if (dirh->size == 0)
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return;
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for (hashline = 0; hashline < DIRHASH_HASHSIZE; hashline++) {
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dirh_e = LIST_FIRST(&dirh->entries[hashline]);
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while (dirh_e) {
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LIST_REMOVE(dirh_e, next);
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pool_put(&dirhash_entry_pool, dirh_e);
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dirh_e = LIST_FIRST(&dirh->entries[hashline]);
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}
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}
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dirh_e = LIST_FIRST(&dirh->free_entries);
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while (dirh_e) {
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LIST_REMOVE(dirh_e, next);
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pool_put(&dirhash_entry_pool, dirh_e);
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dirh_e = LIST_FIRST(&dirh->entries[hashline]);
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}
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dirh->flags &= ~DIRH_COMPLETE;
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dirh->flags |= DIRH_PURGED;
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dirhashsize -= dirh->size;
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dirh->size = 0;
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}
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void
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dirhash_purge(struct dirhash **dirhp)
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{
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struct dirhash *dirh = *dirhp;
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if (dirh == NULL)
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return;
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mutex_enter(&dirhashmutex);
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dirhash_purge_entries(dirh);
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TAILQ_REMOVE(&dirhash_queue, dirh, next);
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pool_put(&dirhash_pool, dirh);
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*dirhp = NULL;
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mutex_exit(&dirhashmutex);
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}
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void
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dirhash_get(struct dirhash **dirhp)
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{
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struct dirhash *dirh;
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uint32_t hashline;
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mutex_enter(&dirhashmutex);
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dirh = *dirhp;
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if (*dirhp == NULL) {
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dirh = pool_get(&dirhash_pool, PR_WAITOK);
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*dirhp = dirh;
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memset(dirh, 0, sizeof(struct dirhash));
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for (hashline = 0; hashline < DIRHASH_HASHSIZE; hashline++)
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LIST_INIT(&dirh->entries[hashline]);
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dirh->size = 0;
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dirh->refcnt = 0;
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dirh->flags = 0;
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} else {
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TAILQ_REMOVE(&dirhash_queue, dirh, next);
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}
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dirh->refcnt++;
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TAILQ_INSERT_HEAD(&dirhash_queue, dirh, next);
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mutex_exit(&dirhashmutex);
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}
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void
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dirhash_put(struct dirhash *dirh)
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{
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mutex_enter(&dirhashmutex);
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dirh->refcnt--;
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mutex_exit(&dirhashmutex);
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}
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void
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dirhash_enter(struct dirhash *dirh,
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struct dirent *dirent, uint64_t offset, uint32_t entry_size, int new)
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{
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struct dirhash *del_dirh, *prev_dirh;
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struct dirhash_entry *dirh_e;
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uint32_t hashvalue, hashline;
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int entrysize;
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/* make sure we have a dirhash to work on */
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KASSERT(dirh);
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KASSERT(dirh->refcnt > 0);
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/* are we trying to re-enter an entry? */
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if (!new && (dirh->flags & DIRH_COMPLETE))
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return;
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/* calculate our hash */
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hashvalue = dirhash_hash(dirent->d_name, dirent->d_namlen);
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hashline = hashvalue & DIRHASH_HASHMASK;
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/* lookup and insert entry if not there yet */
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LIST_FOREACH(dirh_e, &dirh->entries[hashline], next) {
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/* check for hash collision */
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if (dirh_e->hashvalue != hashvalue)
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continue;
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if (dirh_e->offset != offset)
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continue;
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/* got it already */
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KASSERT(dirh_e->d_namlen == dirent->d_namlen);
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KASSERT(dirh_e->entry_size == entry_size);
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return;
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}
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DPRINTF(("dirhash enter %"PRIu64", %d, %d for `%*.*s`\n",
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offset, entry_size, dirent->d_namlen,
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dirent->d_namlen, dirent->d_namlen, dirent->d_name));
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/* check if entry is in free space list */
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LIST_FOREACH(dirh_e, &dirh->free_entries, next) {
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if (dirh_e->offset == offset) {
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DPRINTF(("\tremoving free entry\n"));
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LIST_REMOVE(dirh_e, next);
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break;
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}
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}
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/* ensure we are not passing the dirhash limit */
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entrysize = sizeof(struct dirhash_entry);
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if (dirhashsize + entrysize > maxdirhashsize) {
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del_dirh = TAILQ_LAST(&dirhash_queue, _dirhash);
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KASSERT(del_dirh);
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while (dirhashsize + entrysize > maxdirhashsize) {
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/* no use trying to delete myself */
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if (del_dirh == dirh)
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break;
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prev_dirh = TAILQ_PREV(del_dirh, _dirhash, next);
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if (del_dirh->refcnt == 0)
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dirhash_purge_entries(del_dirh);
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del_dirh = prev_dirh;
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}
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}
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/* add to the hashline */
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dirh_e = pool_get(&dirhash_entry_pool, PR_WAITOK);
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memset(dirh_e, 0, sizeof(struct dirhash_entry));
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dirh_e->hashvalue = hashvalue;
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dirh_e->offset = offset;
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dirh_e->d_namlen = dirent->d_namlen;
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dirh_e->entry_size = entry_size;
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dirh->size += sizeof(struct dirhash_entry);
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dirhashsize += sizeof(struct dirhash_entry);
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LIST_INSERT_HEAD(&dirh->entries[hashline], dirh_e, next);
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}
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void
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dirhash_enter_freed(struct dirhash *dirh, uint64_t offset,
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uint32_t entry_size)
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{
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struct dirhash_entry *dirh_e;
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/* make sure we have a dirhash to work on */
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KASSERT(dirh);
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KASSERT(dirh->refcnt > 0);
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#ifdef DEBUG
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/* check for double entry of free space */
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LIST_FOREACH(dirh_e, &dirh->free_entries, next)
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KASSERT(dirh_e->offset != offset);
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#endif
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DPRINTF(("dirhash enter FREED %"PRIu64", %d\n",
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offset, entry_size));
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dirh_e = pool_get(&dirhash_entry_pool, PR_WAITOK);
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memset(dirh_e, 0, sizeof(struct dirhash_entry));
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dirh_e->hashvalue = 0; /* not relevant */
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dirh_e->offset = offset;
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dirh_e->d_namlen = 0; /* not relevant */
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dirh_e->entry_size = entry_size;
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/* XXX it might be preferable to append them at the tail */
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LIST_INSERT_HEAD(&dirh->free_entries, dirh_e, next);
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dirh->size += sizeof(struct dirhash_entry);
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dirhashsize += sizeof(struct dirhash_entry);
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}
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void
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dirhash_remove(struct dirhash *dirh, struct dirent *dirent,
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uint64_t offset, uint32_t entry_size)
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{
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struct dirhash_entry *dirh_e;
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uint32_t hashvalue, hashline;
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DPRINTF(("dirhash remove %"PRIu64", %d for `%*.*s`\n",
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offset, entry_size,
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dirent->d_namlen, dirent->d_namlen, dirent->d_name));
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/* make sure we have a dirhash to work on */
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KASSERT(dirh);
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KASSERT(dirh->refcnt > 0);
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/* calculate our hash */
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hashvalue = dirhash_hash(dirent->d_name, dirent->d_namlen);
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hashline = hashvalue & DIRHASH_HASHMASK;
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/* lookup entry */
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LIST_FOREACH(dirh_e, &dirh->entries[hashline], next) {
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/* check for hash collision */
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if (dirh_e->hashvalue != hashvalue)
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continue;
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if (dirh_e->offset != offset)
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continue;
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/* got it! */
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KASSERT(dirh_e->d_namlen == dirent->d_namlen);
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KASSERT(dirh_e->entry_size == entry_size);
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LIST_REMOVE(dirh_e, next);
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dirh->size -= sizeof(struct dirhash_entry);
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dirhashsize -= sizeof(struct dirhash_entry);
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dirhash_enter_freed(dirh, offset, entry_size);
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return;
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}
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/* not found! */
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panic("dirhash_remove couldn't find entry in hash table\n");
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}
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/* BUGALERT: don't use result longer than needed, never past the node lock */
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/* call with NULL *result initially and it will return nonzero if again */
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int
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dirhash_lookup(struct dirhash *dirh, const char *d_name, int d_namlen,
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struct dirhash_entry **result)
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{
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struct dirhash_entry *dirh_e;
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uint32_t hashvalue, hashline;
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/* vnode should be locked */
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//KASSERT(VOP_ISLOCKED(dirh->vnode));
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/* make sure we have a dirhash to work on */
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KASSERT(dirh);
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KASSERT(dirh->refcnt > 0);
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/* start where we were */
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if (*result) {
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dirh_e = *result;
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/* retrieve information to avoid recalculation and advance */
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hashvalue = dirh_e->hashvalue;
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dirh_e = LIST_NEXT(*result, next);
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} else {
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/* calculate our hash and lookup all entries in hashline */
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hashvalue = dirhash_hash(d_name, d_namlen);
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hashline = hashvalue & DIRHASH_HASHMASK;
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dirh_e = LIST_FIRST(&dirh->entries[hashline]);
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}
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for (; dirh_e; dirh_e = LIST_NEXT(dirh_e, next)) {
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/* check for hash collision */
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if (dirh_e->hashvalue != hashvalue)
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continue;
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if (dirh_e->d_namlen != d_namlen)
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continue;
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/* might have an entry in the cache */
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*result = dirh_e;
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return 1;
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}
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*result = NULL;
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return 0;
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}
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/* BUGALERT: don't use result longer than needed, never past the node lock */
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/* call with NULL *result initially and it will return nonzero if again */
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int
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dirhash_lookup_freed(struct dirhash *dirh, uint32_t min_entrysize,
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struct dirhash_entry **result)
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{
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struct dirhash_entry *dirh_e;
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//KASSERT(VOP_ISLOCKED(dirh->vnode));
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/* make sure we have a dirhash to work on */
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KASSERT(dirh);
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KASSERT(dirh->refcnt > 0);
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/* start where we were */
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if (*result) {
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dirh_e = LIST_NEXT(*result, next);
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} else {
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/* lookup all entries that match */
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dirh_e = LIST_FIRST(&dirh->free_entries);
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}
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for (; dirh_e; dirh_e = LIST_NEXT(dirh_e, next)) {
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/* check for minimum size */
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if (dirh_e->entry_size < min_entrysize)
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continue;
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/* might be a candidate */
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*result = dirh_e;
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return 1;
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}
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*result = NULL;
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return 0;
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}
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