freebsd-dev/module/zfs/vdev_file.c
Chunwei Chen da8f51e16a Use a dedicated taskq for vdev_file
The introduction of parallel zvol prefetch causes deadlock when using
vdev_file.

spa_async->(spa_namespace_lock)->txg_wait_synced->(wait for txg_sync)
txg_sync->zio_wait->(wait for vdev_file_io_fsync on system_taskq)
zvol_prefetch_minors_impl (on system_taskq)->spa_open_common->(wait for spa_namespace_lock)

We fix this by using dedicated taskq for vdev_file.  This same change
was originally made in commit bc25c93 but reverted in commit aa9af22
when dynamic taskqs were added.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Chunwei Chen <tuxoko@gmail.com>
Closes #5506 
Closes #5495
2016-12-21 10:47:15 -08:00

293 lines
6.5 KiB
C

/*
* CDDL HEADER START
*
* The contents of this file are subject to the terms of the
* Common Development and Distribution License (the "License").
* You may not use this file except in compliance with the License.
*
* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
* or http://www.opensolaris.org/os/licensing.
* See the License for the specific language governing permissions
* and limitations under the License.
*
* When distributing Covered Code, include this CDDL HEADER in each
* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
* If applicable, add the following below this CDDL HEADER, with the
* fields enclosed by brackets "[]" replaced with your own identifying
* information: Portions Copyright [yyyy] [name of copyright owner]
*
* CDDL HEADER END
*/
/*
* Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 2011, 2015 by Delphix. All rights reserved.
*/
#include <sys/zfs_context.h>
#include <sys/spa.h>
#include <sys/spa_impl.h>
#include <sys/vdev_file.h>
#include <sys/vdev_impl.h>
#include <sys/zio.h>
#include <sys/fs/zfs.h>
#include <sys/fm/fs/zfs.h>
#include <sys/abd.h>
/*
* Virtual device vector for files.
*/
static taskq_t *vdev_file_taskq;
static void
vdev_file_hold(vdev_t *vd)
{
ASSERT(vd->vdev_path != NULL);
}
static void
vdev_file_rele(vdev_t *vd)
{
ASSERT(vd->vdev_path != NULL);
}
static int
vdev_file_open(vdev_t *vd, uint64_t *psize, uint64_t *max_psize,
uint64_t *ashift)
{
vdev_file_t *vf;
vnode_t *vp;
vattr_t vattr;
int error;
/* Rotational optimizations only make sense on block devices */
vd->vdev_nonrot = B_TRUE;
/*
* We must have a pathname, and it must be absolute.
*/
if (vd->vdev_path == NULL || vd->vdev_path[0] != '/') {
vd->vdev_stat.vs_aux = VDEV_AUX_BAD_LABEL;
return (SET_ERROR(EINVAL));
}
/*
* Reopen the device if it's not currently open. Otherwise,
* just update the physical size of the device.
*/
if (vd->vdev_tsd != NULL) {
ASSERT(vd->vdev_reopening);
vf = vd->vdev_tsd;
goto skip_open;
}
vf = vd->vdev_tsd = kmem_zalloc(sizeof (vdev_file_t), KM_SLEEP);
/*
* We always open the files from the root of the global zone, even if
* we're in a local zone. If the user has gotten to this point, the
* administrator has already decided that the pool should be available
* to local zone users, so the underlying devices should be as well.
*/
ASSERT(vd->vdev_path != NULL && vd->vdev_path[0] == '/');
error = vn_openat(vd->vdev_path + 1, UIO_SYSSPACE,
spa_mode(vd->vdev_spa) | FOFFMAX, 0, &vp, 0, 0, rootdir, -1);
if (error) {
vd->vdev_stat.vs_aux = VDEV_AUX_OPEN_FAILED;
return (error);
}
vf->vf_vnode = vp;
#ifdef _KERNEL
/*
* Make sure it's a regular file.
*/
if (vp->v_type != VREG) {
vd->vdev_stat.vs_aux = VDEV_AUX_OPEN_FAILED;
return (SET_ERROR(ENODEV));
}
#endif
skip_open:
/*
* Determine the physical size of the file.
*/
vattr.va_mask = AT_SIZE;
error = VOP_GETATTR(vf->vf_vnode, &vattr, 0, kcred, NULL);
if (error) {
vd->vdev_stat.vs_aux = VDEV_AUX_OPEN_FAILED;
return (error);
}
*max_psize = *psize = vattr.va_size;
*ashift = SPA_MINBLOCKSHIFT;
return (0);
}
static void
vdev_file_close(vdev_t *vd)
{
vdev_file_t *vf = vd->vdev_tsd;
if (vd->vdev_reopening || vf == NULL)
return;
if (vf->vf_vnode != NULL) {
(void) VOP_PUTPAGE(vf->vf_vnode, 0, 0, B_INVAL, kcred, NULL);
(void) VOP_CLOSE(vf->vf_vnode, spa_mode(vd->vdev_spa), 1, 0,
kcred, NULL);
}
vd->vdev_delayed_close = B_FALSE;
kmem_free(vf, sizeof (vdev_file_t));
vd->vdev_tsd = NULL;
}
static void
vdev_file_io_strategy(void *arg)
{
zio_t *zio = (zio_t *)arg;
vdev_t *vd = zio->io_vd;
vdev_file_t *vf = vd->vdev_tsd;
ssize_t resid;
void *buf;
if (zio->io_type == ZIO_TYPE_READ)
buf = abd_borrow_buf(zio->io_abd, zio->io_size);
else
buf = abd_borrow_buf_copy(zio->io_abd, zio->io_size);
zio->io_error = vn_rdwr(zio->io_type == ZIO_TYPE_READ ?
UIO_READ : UIO_WRITE, vf->vf_vnode, buf, zio->io_size,
zio->io_offset, UIO_SYSSPACE, 0, RLIM64_INFINITY, kcred, &resid);
if (zio->io_type == ZIO_TYPE_READ)
abd_return_buf_copy(zio->io_abd, buf, zio->io_size);
else
abd_return_buf(zio->io_abd, buf, zio->io_size);
if (resid != 0 && zio->io_error == 0)
zio->io_error = SET_ERROR(ENOSPC);
zio_delay_interrupt(zio);
}
static void
vdev_file_io_fsync(void *arg)
{
zio_t *zio = (zio_t *)arg;
vdev_file_t *vf = zio->io_vd->vdev_tsd;
zio->io_error = VOP_FSYNC(vf->vf_vnode, FSYNC | FDSYNC, kcred, NULL);
zio_interrupt(zio);
}
static void
vdev_file_io_start(zio_t *zio)
{
vdev_t *vd = zio->io_vd;
vdev_file_t *vf = vd->vdev_tsd;
if (zio->io_type == ZIO_TYPE_IOCTL) {
/* XXPOLICY */
if (!vdev_readable(vd)) {
zio->io_error = SET_ERROR(ENXIO);
zio_interrupt(zio);
return;
}
switch (zio->io_cmd) {
case DKIOCFLUSHWRITECACHE:
if (zfs_nocacheflush)
break;
/*
* We cannot safely call vfs_fsync() when PF_FSTRANS
* is set in the current context. Filesystems like
* XFS include sanity checks to verify it is not
* already set, see xfs_vm_writepage(). Therefore
* the sync must be dispatched to a different context.
*/
if (spl_fstrans_check()) {
VERIFY3U(taskq_dispatch(vdev_file_taskq,
vdev_file_io_fsync, zio, TQ_SLEEP), !=,
TASKQID_INVALID);
return;
}
zio->io_error = VOP_FSYNC(vf->vf_vnode, FSYNC | FDSYNC,
kcred, NULL);
break;
default:
zio->io_error = SET_ERROR(ENOTSUP);
}
zio_execute(zio);
return;
}
zio->io_target_timestamp = zio_handle_io_delay(zio);
VERIFY3U(taskq_dispatch(vdev_file_taskq, vdev_file_io_strategy, zio,
TQ_SLEEP), !=, TASKQID_INVALID);
}
/* ARGSUSED */
static void
vdev_file_io_done(zio_t *zio)
{
}
vdev_ops_t vdev_file_ops = {
vdev_file_open,
vdev_file_close,
vdev_default_asize,
vdev_file_io_start,
vdev_file_io_done,
NULL,
vdev_file_hold,
vdev_file_rele,
VDEV_TYPE_FILE, /* name of this vdev type */
B_TRUE /* leaf vdev */
};
void
vdev_file_init(void)
{
vdev_file_taskq = taskq_create("z_vdev_file", MAX(boot_ncpus, 16),
minclsyspri, boot_ncpus, INT_MAX, TASKQ_DYNAMIC);
VERIFY(vdev_file_taskq);
}
void
vdev_file_fini(void)
{
taskq_destroy(vdev_file_taskq);
}
/*
* From userland we access disks just like files.
*/
#ifndef _KERNEL
vdev_ops_t vdev_disk_ops = {
vdev_file_open,
vdev_file_close,
vdev_default_asize,
vdev_file_io_start,
vdev_file_io_done,
NULL,
vdev_file_hold,
vdev_file_rele,
VDEV_TYPE_DISK, /* name of this vdev type */
B_TRUE /* leaf vdev */
};
#endif