vdev_file.c

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/*
 * 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) 2012 by Delphix. All rights reserved.
 */

#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>

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;

        /*
         * 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);
        }

        /*
         * 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;
                vp = vf->vf_vnode;
                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;
                kmem_free(vd->vdev_tsd, sizeof (vdev_file_t));
                vd->vdev_tsd = NULL;
                return (error);
        }

        vf->vf_vnode = vp;

#ifdef _KERNEL
        /*
         * Make sure it's a regular file.
         */
        if (vp->v_type != VREG) {
                (void) VOP_CLOSE(vp, spa_mode(vd->vdev_spa), 1, 0, kcred, NULL);
                vd->vdev_stat.vs_aux = VDEV_AUX_OPEN_FAILED;
                kmem_free(vd->vdev_tsd, sizeof (vdev_file_t));
                vd->vdev_tsd = NULL;
                return (ENODEV);
        }
#endif

skip_open:
        /*
         * Determine the physical size of the file.
         */
        vattr.va_mask = AT_SIZE;
        vn_lock(vp, LK_SHARED | LK_RETRY);
        error = VOP_GETATTR(vp, &vattr, kcred);
        VOP_UNLOCK(vp, 0);
        if (error) {
                (void) VOP_CLOSE(vp, spa_mode(vd->vdev_spa), 1, 0, kcred, NULL);
                vd->vdev_stat.vs_aux = VDEV_AUX_OPEN_FAILED;
                kmem_free(vd->vdev_tsd, sizeof (vdev_file_t));
                vd->vdev_tsd = NULL;
                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_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 int
vdev_file_io_start(zio_t *zio)
{
        vdev_t *vd = zio->io_vd;
        vdev_file_t *vf;
        vnode_t *vp;
        ssize_t resid;

        if (!vdev_readable(vd)) {
                zio->io_error = ENXIO;
                return (ZIO_PIPELINE_CONTINUE);
        }

        vf = vd->vdev_tsd;
        vp = vf->vf_vnode;

        if (zio->io_type == ZIO_TYPE_IOCTL) {
                switch (zio->io_cmd) {
                case DKIOCFLUSHWRITECACHE:
                        zio->io_error = VOP_FSYNC(vp, 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, vp, 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_file_hold,
        vdev_file_rele,
        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_file_hold,
        vdev_file_rele,
        VDEV_TYPE_DISK,         /* name of this vdev type */
        B_TRUE                  /* leaf vdev */
};

#endif