fs/zfs/vdev_disk.c

	vdev_disk.c revision bf82a41b568b2bd31bf9814587eb25ee2e7b05ff
/*
 * 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.
 */

#pragma ident   "%Z%%M% %I% %E% SMI"

#include <sys/zfs_context.h>
#include <sys/spa.h>
#include <sys/refcount.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_common(vdev_t *vd)
{
    vdev_disk_t *dvd;
    dev_t dev;
    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);
    }

    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 the vdev is part of the root pool, we avoid opening it by path.
     * We do this because there is no /dev path available early in boot,
     * and if we try to open the device by path at a later point, we can
     * deadlock when devfsadm attempts to open the underlying backing store
     * file.
     */
    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 && !spa_is_root(vd->vdev_spa)) {
        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 &&
            !spa_is_root(vd->vdev_spa))
            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);
}

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;
    int otyp;

    error = vdev_disk_open_common(vd);
    if (error)
        return (error);

    dvd = vd->vdev_tsd;
    /*
     * 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) {
        char *physpath, *minorname;

        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;
}

int
vdev_disk_physio(ldi_handle_t vd_lh, caddr_t data, size_t size,
    uint64_t offset, int flags)
{
    buf_t *bp;
    int error = 0;

    if (vd_lh == NULL)
        return (EINVAL);

    ASSERT(flags & B_READ || flags & B_WRITE);

    bp = getrbuf(KM_SLEEP);
    bp->b_flags = flags | B_BUSY | B_NOCACHE | B_FAILFAST;
    bp->b_bcount = size;
    bp->b_un.b_addr = (void *)data;
    bp->b_lblkno = lbtodb(offset);
    bp->b_bufsize = size;

    error = ldi_strategy(vd_lh, bp);
    ASSERT(error == 0);
    if ((error = biowait(bp)) == 0 && bp->b_resid != 0)
        error = EIO;
    freerbuf(bp);

    return (error);
}

static int
vdev_disk_probe_io(vdev_t *vd, caddr_t data, size_t size, uint64_t offset,
    int flags)
{
    int error = 0;
    vdev_disk_t *dvd = vd ? vd->vdev_tsd : NULL;

    if (vd == NULL || dvd == NULL || dvd->vd_lh == NULL)
        return (EINVAL);

    error = vdev_disk_physio(dvd->vd_lh, data, size, offset, flags);

    if (zio_injection_enabled && error == 0)
        error = zio_handle_device_injection(vd, EIO);

    return (error);
}

/*
 * 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_disk_probe(vdev_t *vd)
{
    uint64_t offset;
    vdev_t *nvd;
    int l, error = 0, retries = 0;
    char *vl_pad;

    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_pad));

    vl_pad = kmem_alloc(VDEV_SKIP_SIZE, KM_SLEEP);

    /*
     * Try to read and write to a special location on the
     * label. We use the existing vdev initially and only
     * try to create and reopen it if we encounter a failure.
     */
    while ((error = vdev_disk_probe_io(nvd, vl_pad, VDEV_SKIP_SIZE,
        offset, B_READ)) != 0 && retries == 0) {

        nvd = kmem_zalloc(sizeof (vdev_t), KM_SLEEP);
        if (vd->vdev_path)
            nvd->vdev_path = spa_strdup(vd->vdev_path);
        if (vd->vdev_physpath)
            nvd->vdev_physpath = spa_strdup(vd->vdev_physpath);
        if (vd->vdev_devid)
            nvd->vdev_devid = spa_strdup(vd->vdev_devid);
        nvd->vdev_wholedisk = vd->vdev_wholedisk;
        nvd->vdev_guid = vd->vdev_guid;
        nvd->vdev_spa = vd->vdev_spa;
        retries++;

        error = vdev_disk_open_common(nvd);
        if (error)
            break;
    }

    if (!error) {
        error = vdev_disk_probe_io(nvd, vl_pad, VDEV_SKIP_SIZE,
            offset, B_WRITE);
    }

    /* Clean up if we allocated a new vdev */
    if (retries) {
        vdev_disk_close(nvd);
        if (nvd->vdev_path)
            spa_strfree(nvd->vdev_path);
        if (nvd->vdev_physpath)
            spa_strfree(nvd->vdev_physpath);
        if (nvd->vdev_devid)
            spa_strfree(nvd->vdev_devid);
        kmem_free(nvd, sizeof (vdev_t));
    }
    kmem_free(vl_pad, VDEV_SKIP_SIZE);

    /* Reset the failing flag */
    if (!error)
        vd->vdev_is_failing = B_FALSE;

    return (error);
}

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_interrupt(zio);
}

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

    zio->io_error = error;

    zio_interrupt(zio);
}

static int
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_readable(vd)) {
            zio->io_error = ENXIO;
            return (ZIO_PIPELINE_CONTINUE);
        }

        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 (ZIO_PIPELINE_STOP);
            }

            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;
        }

        return (ZIO_PIPELINE_CONTINUE);
    }

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

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

    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_interrupt(zio);
        return (ZIO_PIPELINE_STOP);
    }

    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;

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

    return (ZIO_PIPELINE_STOP);
}

static int
vdev_disk_io_done(zio_t *zio)
{
    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. Otherwise, probe the device and
     * make sure it's still accessible.
     */
    if (zio->io_error == EIO) {
        vdev_t *vd = zio->io_vd;
        vdev_disk_t *dvd = vd->vdev_tsd;
        int state;

        state = DKIO_NONE;
        if (dvd && 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);
        } else if (vdev_probe(vd) != 0) {
            ASSERT(vd->vdev_ops->vdev_op_leaf);
            vd->vdev_is_failing = B_TRUE;
        }
    }

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

    return (ZIO_PIPELINE_CONTINUE);
}

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

/*
 * Given the root disk device pathname, read the label from the device,
 * and construct a configuration nvlist.
 */
nvlist_t *
vdev_disk_read_rootlabel(char *devpath)
{
    nvlist_t *config = NULL;
    ldi_handle_t vd_lh;
    vdev_label_t *label;
    uint64_t s, size;
    int l;

    /*
     * Read the device label and build the nvlist.
     */
    if (ldi_open_by_name(devpath, FREAD, kcred, &vd_lh, zfs_li))
        return (NULL);

    if (ldi_get_size(vd_lh, &s)) {
        (void) ldi_close(vd_lh, FREAD, kcred);
        return (NULL);
    }

    size = P2ALIGN_TYPED(s, sizeof (vdev_label_t), uint64_t);
    label = kmem_alloc(sizeof (vdev_label_t), KM_SLEEP);

    for (l = 0; l < VDEV_LABELS; l++) {
        uint64_t offset, state, txg = 0;

        /* read vdev label */
        offset = vdev_label_offset(size, l, 0);
        if (vdev_disk_physio(vd_lh, (caddr_t)label,
            VDEV_SKIP_SIZE + VDEV_BOOT_HEADER_SIZE +
            VDEV_PHYS_SIZE, offset, B_READ) != 0)
            continue;

        if (nvlist_unpack(label->vl_vdev_phys.vp_nvlist,
            sizeof (label->vl_vdev_phys.vp_nvlist), &config, 0) != 0) {
            config = NULL;
            continue;
        }

        if (nvlist_lookup_uint64(config, ZPOOL_CONFIG_POOL_STATE,
            &state) != 0 || state >= POOL_STATE_DESTROYED) {
            nvlist_free(config);
            config = NULL;
            continue;
        }

        if (nvlist_lookup_uint64(config, ZPOOL_CONFIG_POOL_TXG,
            &txg) != 0 || txg == 0) {
            nvlist_free(config);
            config = NULL;
            continue;
        }

        break;
    }

    kmem_free(label, sizeof (vdev_label_t));
    (void) ldi_close(vd_lh, FREAD, kcred);

    return (config);
}