/*

 * 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/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>

#include <sys/fm/fs/zfs.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;

	/*

	 * The rest of the zio stack only deals with EIO, ECKSUM, and ENXIO.

	 * Rather than teach the rest of the stack about other error

	 * possibilities (EFAULT, etc), we normalize the error value here.

	 */

	zio->io_error = (geterror(bp) != 0 ? EIO : 0);

	if (zio->io_error == 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)