fs/zfs/vdev_disk.c

	vdev_disk.c revision a84224b356ed1e9d5336da9639b65f69263caf62
/*
 * 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_disk.h>
#include <sys/vdev_impl.h>
#include <sys/fs/zfs.h>
#include <sys/zio.h>
#include <sys/sunldi.h>

/*
 * Virtual device vector for disks.
 */

extern ldi_ident_t zfs_li;

typedef struct vdev_disk_buf {
    buf_t   vdb_buf;
    zio_t   *vdb_io;
} vdev_disk_buf_t;

static int
vdev_disk_open(vdev_t *vd, uint64_t *psize, uint64_t *ashift)
{
    vdev_disk_t *dvd;
    struct dk_minfo dkm;
    int error;
    dev_t dev;
    char *physpath, *minorname;
    int otyp;

    /*
     * 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);
    }

    dvd = vd->vdev_tsd = kmem_zalloc(sizeof (vdev_disk_t), KM_SLEEP);

    /*
     * When opening a disk device, we want to preserve the user's original
     * intent.  We always want to open the device by the path the user gave
     * us, even if it is one of multiple paths to the save device.  But we
     * also want to be able to survive disks being removed/recabled.
     * Therefore the sequence of opening devices is:
     *
     * 1. Try opening the device by path.  For legacy pools without the
     *    'whole_disk' property, attempt to fix the path by appending 's0'.
     *
     * 2. If the devid of the device matches the stored value, return
     *    success.
     *
     * 3. Otherwise, the device may have moved.  Try opening the device
     *    by the devid instead.
     *
     */
    if (vd->vdev_devid != NULL) {
        if (ddi_devid_str_decode(vd->vdev_devid, &dvd->vd_devid,
            &dvd->vd_minor) != 0) {
            vd->vdev_stat.vs_aux = VDEV_AUX_BAD_LABEL;
            return (EINVAL);
        }
    }

    error = EINVAL;     /* presume failure */

    if (vd->vdev_path != NULL) {
        ddi_devid_t devid;

        if (vd->vdev_wholedisk == -1ULL) {
            size_t len = strlen(vd->vdev_path) + 3;
            char *buf = kmem_alloc(len, KM_SLEEP);
            ldi_handle_t lh;

            (void) snprintf(buf, len, "%ss0", vd->vdev_path);

            if (ldi_open_by_name(buf, spa_mode, kcred,
                &lh, zfs_li) == 0) {
                spa_strfree(vd->vdev_path);
                vd->vdev_path = buf;
                vd->vdev_wholedisk = 1ULL;
                (void) ldi_close(lh, spa_mode, kcred);
            } else {
                kmem_free(buf, len);
            }
        }

        error = ldi_open_by_name(vd->vdev_path, spa_mode, kcred,
            &dvd->vd_lh, zfs_li);

        /*
         * Compare the devid to the stored value.
         */
        if (error == 0 && vd->vdev_devid != NULL &&
            ldi_get_devid(dvd->vd_lh, &devid) == 0) {
            if (ddi_devid_compare(devid, dvd->vd_devid) != 0) {
                error = EINVAL;
                (void) ldi_close(dvd->vd_lh, spa_mode, kcred);
                dvd->vd_lh = NULL;
            }
            ddi_devid_free(devid);
        }

        /*
         * If we succeeded in opening the device, but 'vdev_wholedisk'
         * is not yet set, then this must be a slice.
         */
        if (error == 0 && vd->vdev_wholedisk == -1ULL)
            vd->vdev_wholedisk = 0;
    }

    /*
     * If we were unable to open by path, or the devid check fails, open by
     * devid instead.
     */
    if (error != 0 && vd->vdev_devid != NULL)
        error = ldi_open_by_devid(dvd->vd_devid, dvd->vd_minor,
            spa_mode, kcred, &dvd->vd_lh, zfs_li);

    /*
     * If all else fails, then try opening by physical path (if available)
     * or the logical path (if we failed due to the devid check).  While not
     * as reliable as the devid, this will give us something, and the higher
     * level vdev validation will prevent us from opening the wrong device.
     */
    if (error) {
        if (vd->vdev_physpath != NULL &&
            (dev = ddi_pathname_to_dev_t(vd->vdev_physpath)) != ENODEV)
            error = ldi_open_by_dev(&dev, OTYP_BLK, spa_mode,
                kcred, &dvd->vd_lh, zfs_li);

        /*
         * Note that we don't support the legacy auto-wholedisk support
         * as above.  This hasn't been used in a very long time and we
         * don't need to propagate its oddities to this edge condition.
         */
        if (error && vd->vdev_path != NULL)
            error = ldi_open_by_name(vd->vdev_path, spa_mode, kcred,
                &dvd->vd_lh, zfs_li);
    }

    if (error) {
        vd->vdev_stat.vs_aux = VDEV_AUX_OPEN_FAILED;
        return (error);
    }

    /*
     * Once a device is opened, verify that the physical device path (if
     * available) is up to date.
     */
    if (ldi_get_dev(dvd->vd_lh, &dev) == 0 &&
        ldi_get_otyp(dvd->vd_lh, &otyp) == 0) {
        physpath = kmem_alloc(MAXPATHLEN, KM_SLEEP);
        minorname = NULL;
        if (ddi_dev_pathname(dev, otyp, physpath) == 0 &&
            ldi_get_minor_name(dvd->vd_lh, &minorname) == 0 &&
            (vd->vdev_physpath == NULL ||
            strcmp(vd->vdev_physpath, physpath) != 0)) {
            if (vd->vdev_physpath)
                spa_strfree(vd->vdev_physpath);
            (void) strlcat(physpath, ":", MAXPATHLEN);
            (void) strlcat(physpath, minorname, MAXPATHLEN);
            vd->vdev_physpath = spa_strdup(physpath);
        }
        if (minorname)
            kmem_free(minorname, strlen(minorname) + 1);
        kmem_free(physpath, MAXPATHLEN);
    }

    /*
     * Determine the actual size of the device.
     */
    if (ldi_get_size(dvd->vd_lh, psize) != 0) {
        vd->vdev_stat.vs_aux = VDEV_AUX_OPEN_FAILED;
        return (EINVAL);
    }

    /*
     * If we own the whole disk, try to enable disk write caching.
     * We ignore errors because it's OK if we can't do it.
     */
    if (vd->vdev_wholedisk == 1) {
        int wce = 1;
        (void) ldi_ioctl(dvd->vd_lh, DKIOCSETWCE, (intptr_t)&wce,
            FKIOCTL, kcred, NULL);
    }

    /*
     * Determine the device's minimum transfer size.
     * If the ioctl isn't supported, assume DEV_BSIZE.
     */
    if (ldi_ioctl(dvd->vd_lh, DKIOCGMEDIAINFO, (intptr_t)&dkm,
        FKIOCTL, kcred, NULL) != 0)
        dkm.dki_lbsize = DEV_BSIZE;

    *ashift = highbit(MAX(dkm.dki_lbsize, SPA_MINBLOCKSIZE)) - 1;

    /*
     * Clear the nowritecache bit, so that on a vdev_reopen() we will
     * try again.
     */
    vd->vdev_nowritecache = B_FALSE;

    return (0);
}

static void
vdev_disk_close(vdev_t *vd)
{
    vdev_disk_t *dvd = vd->vdev_tsd;

    if (dvd == NULL)
        return;

    if (dvd->vd_minor != NULL)
        ddi_devid_str_free(dvd->vd_minor);

    if (dvd->vd_devid != NULL)
        ddi_devid_free(dvd->vd_devid);

    if (dvd->vd_lh != NULL)
        (void) ldi_close(dvd->vd_lh, spa_mode, kcred);

    kmem_free(dvd, sizeof (vdev_disk_t));
    vd->vdev_tsd = NULL;
}

static void
vdev_disk_io_intr(buf_t *bp)
{
    vdev_disk_buf_t *vdb = (vdev_disk_buf_t *)bp;
    zio_t *zio = vdb->vdb_io;

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

    kmem_free(vdb, sizeof (vdev_disk_buf_t));

    zio_next_stage_async(zio);
}

static void
vdev_disk_ioctl_done(void *zio_arg, int error)
{
    zio_t *zio = zio_arg;

    zio->io_error = error;

    zio_next_stage_async(zio);
}

static void
vdev_disk_io_start(zio_t *zio)
{
    vdev_t *vd = zio->io_vd;
    vdev_disk_t *dvd = vd->vdev_tsd;
    vdev_disk_buf_t *vdb;
    buf_t *bp;
    int flags, error;

    if (zio->io_type == ZIO_TYPE_IOCTL) {
        zio_vdev_io_bypass(zio);

        /* XXPOLICY */
        if (vdev_is_dead(vd)) {
            zio->io_error = ENXIO;
            zio_next_stage_async(zio);
            return;
        }

        switch (zio->io_cmd) {

        case DKIOCFLUSHWRITECACHE:

            if (zfs_nocacheflush)
                break;

            if (vd->vdev_nowritecache) {
                zio->io_error = ENOTSUP;
                break;
            }

            zio->io_dk_callback.dkc_callback = vdev_disk_ioctl_done;
            zio->io_dk_callback.dkc_flag = FLUSH_VOLATILE;
            zio->io_dk_callback.dkc_cookie = zio;

            error = ldi_ioctl(dvd->vd_lh, zio->io_cmd,
                (uintptr_t)&zio->io_dk_callback,
                FKIOCTL, kcred, NULL);

            if (error == 0) {
                /*
                 * The ioctl will be done asychronously,
                 * and will call vdev_disk_ioctl_done()
                 * upon completion.
                 */
                return;
            } else if (error == ENOTSUP || error == ENOTTY) {
                /*
                 * If we get ENOTSUP or ENOTTY, we know that
                 * no future attempts will ever succeed.
                 * In this case we set a persistent bit so
                 * that we don't bother with the ioctl in the
                 * future.
                 */
                vd->vdev_nowritecache = B_TRUE;
            }
            zio->io_error = error;

            break;

        default:
            zio->io_error = ENOTSUP;
        }

        zio_next_stage_async(zio);
        return;
    }

    if (zio->io_type == ZIO_TYPE_READ && vdev_cache_read(zio) == 0)
        return;

    if ((zio = vdev_queue_io(zio)) == NULL)
        return;

    flags = (zio->io_type == ZIO_TYPE_READ ? B_READ : B_WRITE);
    flags |= B_BUSY | B_NOCACHE;
    if (zio->io_flags & ZIO_FLAG_FAILFAST)
        flags |= B_FAILFAST;

    vdb = kmem_alloc(sizeof (vdev_disk_buf_t), KM_SLEEP);

    vdb->vdb_io = zio;
    bp = &vdb->vdb_buf;

    bioinit(bp);
    bp->b_flags = flags;
    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_iodone = (int (*)())vdev_disk_io_intr;

    /* XXPOLICY */
    error = vdev_is_dead(vd) ? ENXIO : vdev_error_inject(vd, zio);
    if (error) {
        zio->io_error = error;
        bioerror(bp, error);
        bp->b_resid = bp->b_bcount;
        bp->b_iodone(bp);
        return;
    }

    error = ldi_strategy(dvd->vd_lh, bp);
    /* ldi_strategy() will return non-zero only on programming errors */
    ASSERT(error == 0);
}

static void
vdev_disk_io_done(zio_t *zio)
{
    vdev_t *vd = zio->io_vd;
    vdev_disk_t *dvd = vd->vdev_tsd;
    int state;

    vdev_queue_io_done(zio);

    if (zio->io_type == ZIO_TYPE_WRITE)
        vdev_cache_write(zio);

    if (zio_injection_enabled && zio->io_error == 0)
        zio->io_error = zio_handle_device_injection(zio->io_vd, EIO);

    /*
     * If the device returned EIO, then attempt a DKIOCSTATE ioctl to see if
     * the device has been removed.  If this is the case, then we trigger an
     * asynchronous removal of the device.
     */
    if (zio->io_error == EIO) {
        state = DKIO_NONE;
        if (ldi_ioctl(dvd->vd_lh, DKIOCSTATE, (intptr_t)&state,
            FKIOCTL, kcred, NULL) == 0 &&
            state != DKIO_INSERTED) {
            vd->vdev_remove_wanted = B_TRUE;
            spa_async_request(zio->io_spa, SPA_ASYNC_REMOVE);
        }
    }

    zio_next_stage(zio);
}

vdev_ops_t vdev_disk_ops = {
    vdev_disk_open,
    vdev_disk_close,
    vdev_default_asize,
    vdev_disk_io_start,
    vdev_disk_io_done,
    NULL,
    VDEV_TYPE_DISK,     /* name of this vdev type */
    B_TRUE          /* leaf vdev */
};