30fd5d085d
fixes a problem where we would overwrite old data if we ran out of free entries. Submitted by: sam Approved by: re (scottl)
506 lines
11 KiB
C
506 lines
11 KiB
C
/*
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* Copyright (c) 2002, Jeffrey Roberson <jeff@freebsd.org>
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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 unmodified, this list of conditions, and the following
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* 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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* $FreeBSD$
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*
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*/
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/kernel.h>
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#include <sys/kthread.h>
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#include <sys/lock.h>
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#include <sys/mutex.h>
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#include <sys/namei.h>
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#include <sys/proc.h>
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#include <sys/vnode.h>
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#include <sys/alq.h>
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#include <sys/malloc.h>
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#include <sys/unistd.h>
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#include <sys/fcntl.h>
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#include <sys/eventhandler.h>
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/* Async. Logging Queue */
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struct alq {
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int aq_entmax; /* Max entries */
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int aq_entlen; /* Entry length */
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char *aq_entbuf; /* Buffer for stored entries */
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int aq_flags; /* Queue flags */
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struct mtx aq_mtx; /* Queue lock */
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struct vnode *aq_vp; /* Open vnode handle */
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struct ucred *aq_cred; /* Credentials of the opening thread */
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struct ale *aq_first; /* First ent */
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struct ale *aq_entfree; /* First free ent */
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struct ale *aq_entvalid; /* First ent valid for writing */
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LIST_ENTRY(alq) aq_act; /* List of active queues */
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LIST_ENTRY(alq) aq_link; /* List of all queues */
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};
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#define AQ_WANTED 0x0001 /* Wakeup sleeper when io is done */
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#define AQ_ACTIVE 0x0002 /* on the active list */
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#define AQ_FLUSHING 0x0004 /* doing IO */
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#define AQ_SHUTDOWN 0x0008 /* Queue no longer valid */
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#define ALQ_LOCK(alq) mtx_lock_spin(&(alq)->aq_mtx)
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#define ALQ_UNLOCK(alq) mtx_unlock_spin(&(alq)->aq_mtx)
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static MALLOC_DEFINE(M_ALD, "ALD", "ALD");
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/*
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* The ald_mtx protects the ald_queues list and the ald_active list.
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*/
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static struct mtx ald_mtx;
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static LIST_HEAD(, alq) ald_queues;
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static LIST_HEAD(, alq) ald_active;
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static int ald_shutingdown = 0;
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struct thread *ald_thread;
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static struct proc *ald_proc;
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#define ALD_LOCK() mtx_lock(&ald_mtx)
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#define ALD_UNLOCK() mtx_unlock(&ald_mtx)
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/* Daemon functions */
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static int ald_add(struct alq *);
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static int ald_rem(struct alq *);
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static void ald_startup(void *);
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static void ald_daemon(void);
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static void ald_shutdown(void *, int);
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static void ald_activate(struct alq *);
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static void ald_deactivate(struct alq *);
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/* Internal queue functions */
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static void alq_shutdown(struct alq *);
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static int alq_doio(struct alq *);
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/*
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* Add a new queue to the global list. Fail if we're shutting down.
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*/
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static int
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ald_add(struct alq *alq)
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{
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int error;
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error = 0;
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ALD_LOCK();
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if (ald_shutingdown) {
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error = EBUSY;
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goto done;
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}
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LIST_INSERT_HEAD(&ald_queues, alq, aq_link);
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done:
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ALD_UNLOCK();
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return (error);
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}
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/*
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* Remove a queue from the global list unless we're shutting down. If so,
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* the ald will take care of cleaning up it's resources.
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*/
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static int
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ald_rem(struct alq *alq)
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{
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int error;
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error = 0;
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ALD_LOCK();
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if (ald_shutingdown) {
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error = EBUSY;
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goto done;
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}
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LIST_REMOVE(alq, aq_link);
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done:
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ALD_UNLOCK();
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return (error);
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}
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/*
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* Put a queue on the active list. This will schedule it for writing.
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*/
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static void
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ald_activate(struct alq *alq)
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{
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LIST_INSERT_HEAD(&ald_active, alq, aq_act);
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wakeup(&ald_active);
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}
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static void
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ald_deactivate(struct alq *alq)
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{
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LIST_REMOVE(alq, aq_act);
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alq->aq_flags &= ~AQ_ACTIVE;
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}
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static void
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ald_startup(void *unused)
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{
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mtx_init(&ald_mtx, "ALDmtx", NULL, MTX_DEF|MTX_QUIET);
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LIST_INIT(&ald_queues);
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LIST_INIT(&ald_active);
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}
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static void
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ald_daemon(void)
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{
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int needwakeup;
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struct alq *alq;
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mtx_lock(&Giant);
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ald_thread = FIRST_THREAD_IN_PROC(ald_proc);
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EVENTHANDLER_REGISTER(shutdown_pre_sync, ald_shutdown, NULL,
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SHUTDOWN_PRI_FIRST);
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ALD_LOCK();
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for (;;) {
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while ((alq = LIST_FIRST(&ald_active)) == NULL)
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msleep(&ald_active, &ald_mtx, PWAIT, "aldslp", 0);
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ALQ_LOCK(alq);
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ald_deactivate(alq);
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ALD_UNLOCK();
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needwakeup = alq_doio(alq);
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ALQ_UNLOCK(alq);
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if (needwakeup)
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wakeup(alq);
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ALD_LOCK();
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}
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}
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static void
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ald_shutdown(void *arg, int howto)
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{
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struct alq *alq;
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ALD_LOCK();
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ald_shutingdown = 1;
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while ((alq = LIST_FIRST(&ald_queues)) != NULL) {
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LIST_REMOVE(alq, aq_link);
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ALD_UNLOCK();
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alq_shutdown(alq);
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ALD_LOCK();
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}
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ALD_UNLOCK();
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}
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static void
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alq_shutdown(struct alq *alq)
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{
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ALQ_LOCK(alq);
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/* Stop any new writers. */
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alq->aq_flags |= AQ_SHUTDOWN;
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/* Drain IO */
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while (alq->aq_flags & (AQ_FLUSHING|AQ_ACTIVE)) {
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alq->aq_flags |= AQ_WANTED;
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ALQ_UNLOCK(alq);
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tsleep(alq, PWAIT, "aldclose", 0);
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ALQ_LOCK(alq);
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}
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ALQ_UNLOCK(alq);
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vn_close(alq->aq_vp, FWRITE, alq->aq_cred,
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curthread);
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crfree(alq->aq_cred);
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}
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/*
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* Flush all pending data to disk. This operation will block.
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*/
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static int
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alq_doio(struct alq *alq)
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{
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struct thread *td;
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struct mount *mp;
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struct vnode *vp;
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struct uio auio;
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struct iovec aiov[2];
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struct ale *ale;
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struct ale *alstart;
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int totlen;
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int iov;
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vp = alq->aq_vp;
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td = curthread;
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totlen = 0;
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iov = 0;
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alstart = ale = alq->aq_entvalid;
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alq->aq_entvalid = NULL;
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bzero(&aiov, sizeof(aiov));
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bzero(&auio, sizeof(auio));
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do {
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if (aiov[iov].iov_base == NULL)
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aiov[iov].iov_base = ale->ae_data;
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aiov[iov].iov_len += alq->aq_entlen;
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totlen += alq->aq_entlen;
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/* Check to see if we're wrapping the buffer */
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if (ale->ae_data + alq->aq_entlen != ale->ae_next->ae_data)
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iov++;
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ale->ae_flags &= ~AE_VALID;
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ale = ale->ae_next;
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} while (ale->ae_flags & AE_VALID);
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alq->aq_flags |= AQ_FLUSHING;
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ALQ_UNLOCK(alq);
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if (iov == 2 || aiov[iov].iov_base == NULL)
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iov--;
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auio.uio_iov = &aiov[0];
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auio.uio_offset = 0;
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auio.uio_segflg = UIO_SYSSPACE;
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auio.uio_rw = UIO_WRITE;
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auio.uio_iovcnt = iov + 1;
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auio.uio_resid = totlen;
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auio.uio_td = td;
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/*
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* Do all of the junk required to write now.
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*/
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vn_start_write(vp, &mp, V_WAIT);
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vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, td);
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VOP_LEASE(vp, td, alq->aq_cred, LEASE_WRITE);
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/* XXX error ignored */
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VOP_WRITE(vp, &auio, IO_UNIT | IO_APPEND, alq->aq_cred);
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VOP_UNLOCK(vp, 0, td);
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vn_finished_write(mp);
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ALQ_LOCK(alq);
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alq->aq_flags &= ~AQ_FLUSHING;
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if (alq->aq_entfree == NULL)
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alq->aq_entfree = alstart;
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if (alq->aq_flags & AQ_WANTED) {
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alq->aq_flags &= ~AQ_WANTED;
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return (1);
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}
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return(0);
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}
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static struct kproc_desc ald_kp = {
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"ALQ Daemon",
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ald_daemon,
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&ald_proc
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};
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SYSINIT(aldthread, SI_SUB_KTHREAD_IDLE, SI_ORDER_ANY, kproc_start, &ald_kp)
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SYSINIT(ald, SI_SUB_LOCK, SI_ORDER_ANY, ald_startup, NULL)
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/* User visible queue functions */
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/*
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* Create the queue data structure, allocate the buffer, and open the file.
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*/
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int
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alq_open(struct alq **alqp, const char *file, int size, int count)
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{
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struct thread *td;
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struct nameidata nd;
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struct ale *ale;
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struct ale *alp;
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struct alq *alq;
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char *bufp;
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int flags;
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int error;
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int i;
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*alqp = NULL;
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td = curthread;
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NDINIT(&nd, LOOKUP, NOFOLLOW, UIO_SYSSPACE, file, td);
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flags = FWRITE | O_NOFOLLOW | O_CREAT;
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error = vn_open(&nd, &flags, 0);
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if (error)
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return (error);
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NDFREE(&nd, NDF_ONLY_PNBUF);
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/* We just unlock so we hold a reference */
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VOP_UNLOCK(nd.ni_vp, 0, td);
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alq = malloc(sizeof(*alq), M_ALD, M_WAITOK|M_ZERO);
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alq->aq_entbuf = malloc(count * size, M_ALD, M_WAITOK|M_ZERO);
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alq->aq_first = malloc(sizeof(*ale) * count, M_ALD, M_WAITOK|M_ZERO);
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alq->aq_vp = nd.ni_vp;
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alq->aq_cred = crhold(td->td_ucred);
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alq->aq_entmax = count;
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alq->aq_entlen = size;
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alq->aq_entfree = alq->aq_first;
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mtx_init(&alq->aq_mtx, "ALD Queue", NULL, MTX_SPIN|MTX_QUIET);
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bufp = alq->aq_entbuf;
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ale = alq->aq_first;
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alp = NULL;
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/* Match up entries with buffers */
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for (i = 0; i < count; i++) {
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if (alp)
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alp->ae_next = ale;
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ale->ae_data = bufp;
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alp = ale;
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ale++;
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bufp += size;
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}
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alp->ae_next = alq->aq_first;
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if ((error = ald_add(alq)) != 0)
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return (error);
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*alqp = alq;
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return (0);
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}
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/*
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* Copy a new entry into the queue. If the operation would block either
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* wait or return an error depending on the value of waitok.
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*/
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int
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alq_write(struct alq *alq, void *data, int waitok)
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{
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struct ale *ale;
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if ((ale = alq_get(alq, waitok)) == NULL)
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return (EWOULDBLOCK);
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bcopy(data, ale->ae_data, alq->aq_entlen);
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alq_post(alq, ale);
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return (0);
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}
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struct ale *
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alq_get(struct alq *alq, int waitok)
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{
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struct ale *ale;
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struct ale *aln;
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ale = NULL;
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ALQ_LOCK(alq);
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/* Loop until we get an entry or we're shutting down */
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while ((alq->aq_flags & AQ_SHUTDOWN) == 0 &&
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(ale = alq->aq_entfree) == NULL &&
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(waitok & ALQ_WAITOK)) {
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alq->aq_flags |= AQ_WANTED;
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ALQ_UNLOCK(alq);
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tsleep(alq, PWAIT, "alqget", 0);
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ALQ_LOCK(alq);
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}
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if (ale != NULL) {
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aln = ale->ae_next;
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if ((aln->ae_flags & AE_VALID) == 0)
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alq->aq_entfree = aln;
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else
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alq->aq_entfree = NULL;
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} else
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ALQ_UNLOCK(alq);
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return (ale);
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}
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void
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alq_post(struct alq *alq, struct ale *ale)
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{
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int activate;
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ale->ae_flags |= AE_VALID;
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if (alq->aq_entvalid == NULL)
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alq->aq_entvalid = ale;
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if ((alq->aq_flags & AQ_ACTIVE) == 0) {
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alq->aq_flags |= AQ_ACTIVE;
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activate = 1;
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} else
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activate = 0;
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ALQ_UNLOCK(alq);
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if (activate) {
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ALD_LOCK();
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ald_activate(alq);
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ALD_UNLOCK();
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}
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}
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void
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alq_flush(struct alq *alq)
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{
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int needwakeup = 0;
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ALD_LOCK();
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ALQ_LOCK(alq);
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if (alq->aq_flags & AQ_ACTIVE) {
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ald_deactivate(alq);
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ALD_UNLOCK();
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needwakeup = alq_doio(alq);
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} else
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ALD_UNLOCK();
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ALQ_UNLOCK(alq);
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if (needwakeup)
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wakeup(alq);
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}
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/*
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* Flush remaining data, close the file and free all resources.
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*/
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void
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alq_close(struct alq *alq)
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{
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/*
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* If we're already shuting down someone else will flush and close
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* the vnode.
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*/
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if (ald_rem(alq) != 0)
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return;
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/*
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* Drain all pending IO.
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*/
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alq_shutdown(alq);
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mtx_destroy(&alq->aq_mtx);
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free(alq->aq_first, M_ALD);
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free(alq->aq_entbuf, M_ALD);
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free(alq, M_ALD);
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}
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