vdev_file.c revision 1f7ad2e1275fff503991bf4b43bc5cf1d815669f
/*
* 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 2007 Sun Microsystems, Inc. All rights reserved.
* Use is subject to license terms.
*/
#pragma ident "%Z%%M% %I% %E% SMI"
#include <sys/zfs_context.h>
#include <sys/spa.h>
#include <sys/vdev_file.h>
#include <sys/vdev_impl.h>
#include <sys/zio.h>
#include <sys/fs/zfs.h>
/*
* Virtual device vector for files.
*/
static int
vdev_file_open_common(vdev_t *vd)
{
vdev_file_t *vf;
vnode_t *vp;
int error;
/*
* 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 (EINVAL);
}
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 | 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 (ENODEV);
}
#endif
return (0);
}
static int
vdev_file_open(vdev_t *vd, uint64_t *psize, uint64_t *ashift)
{
vdev_file_t *vf;
vattr_t vattr;
int error;
if ((error = vdev_file_open_common(vd)) != 0)
return (error);
vf = vd->vdev_tsd;
/*
* 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);
}
*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 (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, 1, 0, kcred, NULL);
VN_RELE(vf->vf_vnode);
}
kmem_free(vf, sizeof (vdev_file_t));
vd->vdev_tsd = NULL;
}
static int
vdev_file_probe_io(vdev_t *vd, caddr_t data, size_t size, uint64_t offset,
enum uio_rw rw)
{
vdev_file_t *vf = vd->vdev_tsd;
ssize_t resid;
int error = 0;
if (vd == NULL || vf == NULL || vf->vf_vnode == NULL)
return (EINVAL);
ASSERT(rw == UIO_READ || rw == UIO_WRITE);
error = vn_rdwr(rw, vf->vf_vnode, data, size, offset, UIO_SYSSPACE,
0, RLIM64_INFINITY, kcred, &resid);
if (error || resid != 0)
return (EIO);
return (0);
}
/*
* Determine if the underlying device is accessible by reading and writing
* to a known location. We must be able to do this during syncing context
* and thus we cannot set the vdev state directly.
*/
static int
vdev_file_probe(vdev_t *vd)
{
vdev_t *nvd;
char *vl_boot;
uint64_t offset;
int l, error = 0, retries = 0;
if (vd == NULL)
return (EINVAL);
/* Hijack the current vdev */
nvd = vd;
/*
* Pick a random label to rewrite.
*/
l = spa_get_random(VDEV_LABELS);
ASSERT(l < VDEV_LABELS);
offset = vdev_label_offset(vd->vdev_psize, l,
offsetof(vdev_label_t, vl_boot_header));
vl_boot = kmem_alloc(VDEV_BOOT_HEADER_SIZE, KM_SLEEP);
while ((error = vdev_file_probe_io(nvd, vl_boot, VDEV_BOOT_HEADER_SIZE,
offset, UIO_READ)) != 0 && retries == 0) {
/*
* If we failed with the vdev that was passed in then
* try allocating a new one and try again.
*/
nvd = kmem_zalloc(sizeof (vdev_t), KM_SLEEP);
if (vd->vdev_path)
nvd->vdev_path = spa_strdup(vd->vdev_path);
retries++;
error = vdev_file_open_common(nvd);
if (error)
break;
}
if ((spa_mode & FWRITE) && !error) {
error = vdev_file_probe_io(nvd, vl_boot, VDEV_BOOT_HEADER_SIZE,
offset, UIO_WRITE);
}
if (retries) {
vdev_file_close(nvd);
if (nvd->vdev_path)
spa_strfree(nvd->vdev_path);
kmem_free(nvd, sizeof (vdev_t));
}
kmem_free(vl_boot, VDEV_BOOT_HEADER_SIZE);
if (!error)
vd->vdev_is_failing = B_FALSE;
return (error);
}
static void
vdev_file_io_start(zio_t *zio)
{
vdev_t *vd = zio->io_vd;
vdev_file_t *vf = vd->vdev_tsd;
ssize_t resid;
int error;
if (zio->io_type == ZIO_TYPE_IOCTL) {
zio_vdev_io_bypass(zio);
/* XXPOLICY */
if (!vdev_readable(vd)) {
zio->io_error = ENXIO;
zio_next_stage_async(zio);
return;
}
switch (zio->io_cmd) {
case DKIOCFLUSHWRITECACHE:
zio->io_error = VOP_FSYNC(vf->vf_vnode, FSYNC | FDSYNC,
kcred, NULL);
dprintf("fsync(%s) = %d\n", vdev_description(vd),
zio->io_error);
break;
default:
zio->io_error = ENOTSUP;
}
zio_next_stage_async(zio);
return;
}
/*
* In the kernel, don't bother double-caching, but in userland,
* we want to test the vdev_cache code.
*/
#ifndef _KERNEL
if (zio->io_type == ZIO_TYPE_READ && vdev_cache_read(zio) == 0)
return;
#endif
if ((zio = vdev_queue_io(zio)) == NULL)
return;
/* XXPOLICY */
if (zio->io_type == ZIO_TYPE_WRITE)
error = vdev_writeable(vd) ? vdev_error_inject(vd, zio) : ENXIO;
else
error = vdev_readable(vd) ? vdev_error_inject(vd, zio) : ENXIO;
error = (vd->vdev_remove_wanted || vd->vdev_is_failing) ? ENXIO : error;
if (error) {
zio->io_error = error;
zio_next_stage_async(zio);
return;
}
zio->io_error = vn_rdwr(zio->io_type == ZIO_TYPE_READ ?
UIO_READ : UIO_WRITE, vf->vf_vnode, zio->io_data,
zio->io_size, zio->io_offset, UIO_SYSSPACE,
0, RLIM64_INFINITY, kcred, &resid);
if (resid != 0 && zio->io_error == 0)
zio->io_error = ENOSPC;
zio_next_stage_async(zio);
}
static void
vdev_file_io_done(zio_t *zio)
{
if (zio_injection_enabled && zio->io_error == 0)
zio->io_error = zio_handle_device_injection(zio->io_vd, EIO);
/*
* If an error has been encountered then attempt to probe the device
* to determine if it's still accessible.
*/
if (zio->io_error == EIO) {
vdev_t *vd = zio->io_vd;
if (vdev_probe(vd) != 0)
vd->vdev_is_failing = B_TRUE;
}
vdev_queue_io_done(zio);
#ifndef _KERNEL
if (zio->io_type == ZIO_TYPE_WRITE)
vdev_cache_write(zio);
#endif
zio_next_stage(zio);
}
vdev_ops_t vdev_file_ops = {
vdev_file_open,
vdev_file_close,
vdev_file_probe,
vdev_default_asize,
vdev_file_io_start,
vdev_file_io_done,
NULL,
VDEV_TYPE_FILE, /* name of this vdev type */
B_TRUE /* leaf vdev */
};
/*
* From userland we access disks just like files.
*/
#ifndef _KERNEL
vdev_ops_t vdev_disk_ops = {
vdev_file_open,
vdev_file_close,
vdev_file_probe,
vdev_default_asize,
vdev_file_io_start,
vdev_file_io_done,
NULL,
VDEV_TYPE_DISK, /* name of this vdev type */
B_TRUE /* leaf vdev */
};
#endif