fs/zfs/vdev_file.c

	vdev_file.c revision 8ad4d6dd86f5bc65fb3afa566c8133f3bac21648
/*
 * 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 2008 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

#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>
#include <sys/fm/fs/zfs.h>

/*
 * Virtual device vector for files.
 */

static int
vdev_file_open(vdev_t *vd, uint64_t *psize, uint64_t *ashift)
{
    vdev_file_t *vf;
    vnode_t *vp;
    vattr_t vattr;
    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(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 (ENODEV);
    }
#endif
    /*
     * 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(vd->vdev_spa), 1, 0,
            kcred, NULL);
        VN_RELE(vf->vf_vnode);
    }

    kmem_free(vf, sizeof (vdev_file_t));
    vd->vdev_tsd = NULL;
}

static int
vdev_file_io_start(zio_t *zio)
{
    vdev_t *vd = zio->io_vd;
    vdev_file_t *vf = vd->vdev_tsd;
    ssize_t resid;

    if (zio->io_type == ZIO_TYPE_IOCTL) {
        /* XXPOLICY */
        if (!vdev_readable(vd)) {
            zio->io_error = ENXIO;
            return (ZIO_PIPELINE_CONTINUE);
        }

        switch (zio->io_cmd) {
        case DKIOCFLUSHWRITECACHE:
            zio->io_error = VOP_FSYNC(vf->vf_vnode, FSYNC | FDSYNC,
                kcred, NULL);
            break;
        default:
            zio->io_error = ENOTSUP;
        }

        return (ZIO_PIPELINE_CONTINUE);
    }

    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_interrupt(zio);

    return (ZIO_PIPELINE_STOP);
}

/* 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_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_default_asize,
    vdev_file_io_start,
    vdev_file_io_done,
    NULL,
    VDEV_TYPE_DISK,     /* name of this vdev type */
    B_TRUE          /* leaf vdev */
};

#endif