fs/zfs/vdev_file.c

	vdev_file.c revision 97e81309571898df9fdd94aab1216dfcf23e060b
/*
 * 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>

/*
 * Virtual device vector for files.
 */

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 (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);
        VN_RELE(vf->vf_vnode);
    }

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

/*
 * Implements the interrupt side for file vdev types. This routine will be
 * called when the I/O completes allowing us to transfer the I/O to the
 * interrupt taskqs. For consistency, the code structure mimics disk vdev
 * types.
 */
static void
vdev_file_io_intr(buf_t *bp)
{
    vdev_buf_t *vb = (vdev_buf_t *)bp;
    zio_t *zio = vb->vb_io;

    zio->io_error = (geterror(bp) != 0 ? EIO : 0);
    if (zio->io_error == 0 && bp->b_resid != 0)
        zio->io_error = SET_ERROR(ENOSPC);

    kmem_free(vb, sizeof (vdev_buf_t));
    zio_delay_interrupt(zio);
}

static void
vdev_file_io_strategy(void *arg)
{
    buf_t *bp = arg;
    vnode_t *vp = bp->b_private;
    ssize_t resid;
    int error;

    error = vn_rdwr((bp->b_flags & B_READ) ? UIO_READ : UIO_WRITE,
        vp, bp->b_un.b_addr, bp->b_bcount, ldbtob(bp->b_lblkno),
        UIO_SYSSPACE, 0, RLIM64_INFINITY, kcred, &resid);

    if (error == 0) {
        bp->b_resid = resid;
        biodone(bp);
    } else {
        bioerror(bp, error);
        biodone(bp);
    }
}

static void
vdev_file_io_start(zio_t *zio)
{
    vdev_t *vd = zio->io_vd;
    vdev_file_t *vf = vd->vdev_tsd;
    vdev_buf_t *vb;
    buf_t *bp;

    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:
            zio->io_error = VOP_FSYNC(vf->vf_vnode, FSYNC | FDSYNC,
                kcred, NULL);
            break;
        default:
            zio->io_error = SET_ERROR(ENOTSUP);
        }

        zio_execute(zio);
        return;
    }

    ASSERT(zio->io_type == ZIO_TYPE_READ || zio->io_type == ZIO_TYPE_WRITE);
    zio->io_target_timestamp = zio_handle_io_delay(zio);

    vb = kmem_alloc(sizeof (vdev_buf_t), KM_SLEEP);

    vb->vb_io = zio;
    bp = &vb->vb_buf;

    bioinit(bp);
    bp->b_flags = (zio->io_type == ZIO_TYPE_READ ? B_READ : B_WRITE);
    bp->b_bcount = zio->io_size;
    bp->b_un.b_addr = zio->io_data;
    bp->b_lblkno = lbtodb(zio->io_offset);
    bp->b_bufsize = zio->io_size;
    bp->b_private = vf->vf_vnode;
    bp->b_iodone = (int (*)())vdev_file_io_intr;

    VERIFY3U(taskq_dispatch(system_taskq, vdev_file_io_strategy, bp,
        TQ_SLEEP), !=, 0);
}

/* 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