/*-
* Copyright (c) 2002, Jeffrey Roberson <jeff@freebsd.org>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice unmodified, this list of conditions, and the following
* disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include "opt_mac.h"
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/kthread.h>
#include <sys/lock.h>
#include <sys/mac.h>
#include <sys/mutex.h>
#include <sys/namei.h>
#include <sys/proc.h>
#include <sys/vnode.h>
#include <sys/alq.h>
#include <sys/malloc.h>
#include <sys/unistd.h>
#include <sys/fcntl.h>
#include <sys/eventhandler.h>
/* Async. Logging Queue */
struct alq {
int aq_entmax; /* Max entries */
int aq_entlen; /* Entry length */
char *aq_entbuf; /* Buffer for stored entries */
int aq_flags; /* Queue flags */
struct mtx aq_mtx; /* Queue lock */
struct vnode *aq_vp; /* Open vnode handle */
struct ucred *aq_cred; /* Credentials of the opening thread */
struct ale *aq_first; /* First ent */
struct ale *aq_entfree; /* First free ent */
struct ale *aq_entvalid; /* First ent valid for writing */
LIST_ENTRY(alq) aq_act; /* List of active queues */
LIST_ENTRY(alq) aq_link; /* List of all queues */
};
#define AQ_WANTED 0x0001 /* Wakeup sleeper when io is done */
#define AQ_ACTIVE 0x0002 /* on the active list */
#define AQ_FLUSHING 0x0004 /* doing IO */
#define AQ_SHUTDOWN 0x0008 /* Queue no longer valid */
#define ALQ_LOCK(alq) mtx_lock_spin(&(alq)->aq_mtx)
#define ALQ_UNLOCK(alq) mtx_unlock_spin(&(alq)->aq_mtx)
static MALLOC_DEFINE(M_ALD, "ALD", "ALD");
/*
* The ald_mtx protects the ald_queues list and the ald_active list.
*/
static struct mtx ald_mtx;
static LIST_HEAD(, alq) ald_queues;
static LIST_HEAD(, alq) ald_active;
static int ald_shutingdown = 0;
struct thread *ald_thread;
static struct proc *ald_proc;
#define ALD_LOCK() mtx_lock(&ald_mtx)
#define ALD_UNLOCK() mtx_unlock(&ald_mtx)
/* Daemon functions */
static int ald_add(struct alq *);
static int ald_rem(struct alq *);
static void ald_startup(void *);
static void ald_daemon(void);
static void ald_shutdown(void *, int);
static void ald_activate(struct alq *);
static void ald_deactivate(struct alq *);
/* Internal queue functions */
static void alq_shutdown(struct alq *);
static int alq_doio(struct alq *);
/*
* Add a new queue to the global list. Fail if we're shutting down.
*/
static int
ald_add(struct alq *alq)
{
int error;
error = 0;
ALD_LOCK();
if (ald_shutingdown) {
error = EBUSY;
goto done;
}
LIST_INSERT_HEAD(&ald_queues, alq, aq_link);
done:
ALD_UNLOCK();
return (error);
}
/*
* Remove a queue from the global list unless we're shutting down. If so,
* the ald will take care of cleaning up it's resources.
*/
static int
ald_rem(struct alq *alq)
{
int error;
error = 0;
ALD_LOCK();
if (ald_shutingdown) {
error = EBUSY;
goto done;
}
LIST_REMOVE(alq, aq_link);
done:
ALD_UNLOCK();
return (error);
}
/*
* Put a queue on the active list. This will schedule it for writing.
*/
static void
ald_activate(struct alq *alq)
{
LIST_INSERT_HEAD(&ald_active, alq, aq_act);
wakeup(&ald_active);
}
static void
ald_deactivate(struct alq *alq)
{
LIST_REMOVE(alq, aq_act);
alq->aq_flags &= ~AQ_ACTIVE;
}
static void
ald_startup(void *unused)
{
mtx_init(&ald_mtx, "ALDmtx", NULL, MTX_DEF|MTX_QUIET);
LIST_INIT(&ald_queues);
LIST_INIT(&ald_active);
}
static void
ald_daemon(void)
{
int needwakeup;
struct alq *alq;
mtx_lock(&Giant);
ald_thread = FIRST_THREAD_IN_PROC(ald_proc);
EVENTHANDLER_REGISTER(shutdown_pre_sync, ald_shutdown, NULL,
SHUTDOWN_PRI_FIRST);
ALD_LOCK();
for (;;) {
while ((alq = LIST_FIRST(&ald_active)) == NULL)
msleep(&ald_active, &ald_mtx, PWAIT, "aldslp", 0);
ALQ_LOCK(alq);
ald_deactivate(alq);
ALD_UNLOCK();
needwakeup = alq_doio(alq);
ALQ_UNLOCK(alq);
if (needwakeup)
wakeup(alq);
ALD_LOCK();
}
}
static void
ald_shutdown(void *arg, int howto)
{
struct alq *alq;
ALD_LOCK();
ald_shutingdown = 1;
while ((alq = LIST_FIRST(&ald_queues)) != NULL) {
LIST_REMOVE(alq, aq_link);
ALD_UNLOCK();
alq_shutdown(alq);
ALD_LOCK();
}
ALD_UNLOCK();
}
static void
alq_shutdown(struct alq *alq)
{
ALQ_LOCK(alq);
/* Stop any new writers. */
alq->aq_flags |= AQ_SHUTDOWN;
/* Drain IO */
while (alq->aq_flags & (AQ_FLUSHING|AQ_ACTIVE)) {
alq->aq_flags |= AQ_WANTED;
ALQ_UNLOCK(alq);
tsleep(alq, PWAIT, "aldclose", 0);
ALQ_LOCK(alq);
}
ALQ_UNLOCK(alq);
vn_close(alq->aq_vp, FWRITE, alq->aq_cred,
curthread);
crfree(alq->aq_cred);
}
/*
* Flush all pending data to disk. This operation will block.
*/
static int
alq_doio(struct alq *alq)
{
struct thread *td;
struct mount *mp;
struct vnode *vp;
struct uio auio;
struct iovec aiov[2];
struct ale *ale;
struct ale *alstart;
int totlen;
int iov;
vp = alq->aq_vp;
td = curthread;
totlen = 0;
iov = 0;
alstart = ale = alq->aq_entvalid;
alq->aq_entvalid = NULL;
bzero(&aiov, sizeof(aiov));
bzero(&auio, sizeof(auio));
do {
if (aiov[iov].iov_base == NULL)
aiov[iov].iov_base = ale->ae_data;
aiov[iov].iov_len += alq->aq_entlen;
totlen += alq->aq_entlen;
/* Check to see if we're wrapping the buffer */
if (ale->ae_data + alq->aq_entlen != ale->ae_next->ae_data)
iov++;
ale->ae_flags &= ~AE_VALID;
ale = ale->ae_next;
} while (ale->ae_flags & AE_VALID);
alq->aq_flags |= AQ_FLUSHING;
ALQ_UNLOCK(alq);
if (iov == 2 || aiov[iov].iov_base == NULL)
iov--;
auio.uio_iov = &aiov[0];
auio.uio_offset = 0;
auio.uio_segflg = UIO_SYSSPACE;
auio.uio_rw = UIO_WRITE;
auio.uio_iovcnt = iov + 1;
auio.uio_resid = totlen;
auio.uio_td = td;
/*
* Do all of the junk required to write now.
*/
vn_start_write(vp, &mp, V_WAIT);
vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, td);
VOP_LEASE(vp, td, alq->aq_cred, LEASE_WRITE);
/*
* XXX: VOP_WRITE error checks are ignored.
*/
#ifdef MAC
if (mac_check_vnode_write(alq->aq_cred, NOCRED, vp) == 0)
#endif
VOP_WRITE(vp, &auio, IO_UNIT | IO_APPEND, alq->aq_cred);
VOP_UNLOCK(vp, 0, td);
vn_finished_write(mp);
ALQ_LOCK(alq);
alq->aq_flags &= ~AQ_FLUSHING;
if (alq->aq_entfree == NULL)
alq->aq_entfree = alstart;
if (alq->aq_flags & AQ_WANTED) {
alq->aq_flags &= ~AQ_WANTED;
return (1);
}
return(0);
}
static struct kproc_desc ald_kp = {
"ALQ Daemon",
ald_daemon,
&ald_proc
};
SYSINIT(aldthread, SI_SUB_KTHREAD_IDLE, SI_ORDER_ANY, kproc_start, &ald_kp)
SYSINIT(ald, SI_SUB_LOCK, SI_ORDER_ANY, ald_startup, NULL)
/* User visible queue functions */
/*
* Create the queue data structure, allocate the buffer, and open the file.
*/
int
alq_open(struct alq **alqp, const char *file, struct ucred *cred, int cmode,
int size, int count)
{
struct thread *td;
struct nameidata nd;
struct ale *ale;
struct ale *alp;
struct alq *alq;
char *bufp;
int flags;
int error;
int i;
*alqp = NULL;
td = curthread;
NDINIT(&nd, LOOKUP, NOFOLLOW, UIO_SYSSPACE, file, td);
flags = FWRITE | O_NOFOLLOW | O_CREAT;
error = vn_open_cred(&nd, &flags, cmode, cred, -1);
if (error)
return (error);
NDFREE(&nd, NDF_ONLY_PNBUF);
/* We just unlock so we hold a reference */
VOP_UNLOCK(nd.ni_vp, 0, td);
alq = malloc(sizeof(*alq), M_ALD, M_WAITOK|M_ZERO);
alq->aq_entbuf = malloc(count * size, M_ALD, M_WAITOK|M_ZERO);
alq->aq_first = malloc(sizeof(*ale) * count, M_ALD, M_WAITOK|M_ZERO);
alq->aq_vp = nd.ni_vp;
alq->aq_cred = crhold(cred);
alq->aq_entmax = count;
alq->aq_entlen = size;
alq->aq_entfree = alq->aq_first;
mtx_init(&alq->aq_mtx, "ALD Queue", NULL, MTX_SPIN|MTX_QUIET);
bufp = alq->aq_entbuf;
ale = alq->aq_first;
alp = NULL;
/* Match up entries with buffers */
for (i = 0; i < count; i++) {
if (alp)
alp->ae_next = ale;
ale->ae_data = bufp;
alp = ale;
ale++;
bufp += size;
}
alp->ae_next = alq->aq_first;
if ((error = ald_add(alq)) != 0)
return (error);
*alqp = alq;
return (0);
}
/*
* Copy a new entry into the queue. If the operation would block either
* wait or return an error depending on the value of waitok.
*/
int
alq_write(struct alq *alq, void *data, int waitok)
{
struct ale *ale;
if ((ale = alq_get(alq, waitok)) == NULL)
return (EWOULDBLOCK);
bcopy(data, ale->ae_data, alq->aq_entlen);
alq_post(alq, ale);
return (0);
}
struct ale *
alq_get(struct alq *alq, int waitok)
{
struct ale *ale;
struct ale *aln;
ale = NULL;
ALQ_LOCK(alq);
/* Loop until we get an entry or we're shutting down */
while ((alq->aq_flags & AQ_SHUTDOWN) == 0 &&
(ale = alq->aq_entfree) == NULL &&
(waitok & ALQ_WAITOK)) {
alq->aq_flags |= AQ_WANTED;
ALQ_UNLOCK(alq);
tsleep(alq, PWAIT, "alqget", 0);
ALQ_LOCK(alq);
}
if (ale != NULL) {
aln = ale->ae_next;
if ((aln->ae_flags & AE_VALID) == 0)
alq->aq_entfree = aln;
else
alq->aq_entfree = NULL;
} else
ALQ_UNLOCK(alq);
return (ale);
}
void
alq_post(struct alq *alq, struct ale *ale)
{
int activate;
ale->ae_flags |= AE_VALID;
if (alq->aq_entvalid == NULL)
alq->aq_entvalid = ale;
if ((alq->aq_flags & AQ_ACTIVE) == 0) {
alq->aq_flags |= AQ_ACTIVE;
activate = 1;
} else
activate = 0;
ALQ_UNLOCK(alq);
if (activate) {
ALD_LOCK();
ald_activate(alq);
ALD_UNLOCK();
}
}
void
alq_flush(struct alq *alq)
{
int needwakeup = 0;
ALD_LOCK();
ALQ_LOCK(alq);
if (alq->aq_flags & AQ_ACTIVE) {
ald_deactivate(alq);
ALD_UNLOCK();
needwakeup = alq_doio(alq);
} else
ALD_UNLOCK();
ALQ_UNLOCK(alq);
if (needwakeup)
wakeup(alq);
}
/*
* Flush remaining data, close the file and free all resources.
*/
void
alq_close(struct alq *alq)
{
/*
* If we're already shuting down someone else will flush and close
* the vnode.
*/
if (ald_rem(alq) != 0)
return;
/*
* Drain all pending IO.
*/
alq_shutdown(alq);
mtx_destroy(&alq->aq_mtx);
free(alq->aq_first, M_ALD);
free(alq->aq_entbuf, M_ALD);
free(alq, M_ALD);
}
