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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 2010 Sun Microsystems, Inc. All rights reserved.
* Use is subject to license terms.
*/
/*
* Copyright (c) 2012, 2018 by Delphix. All rights reserved.
*/
#include <sys/zfs_context.h>
#include <sys/spa.h>
#include <sys/spa_impl.h>
#include <sys/dsl_pool.h>
#include <sys/dsl_scan.h>
#include <sys/vdev_impl.h>
#include <sys/zio.h>
#include <sys/abd.h>
#include <sys/fs/zfs.h>
/*
* Virtual device vector for mirroring.
*/
typedef struct mirror_child {
vdev_t *mc_vd;
uint64_t mc_offset;
int mc_error;
uint8_t mc_tried;
uint8_t mc_skipped;
uint8_t mc_speculative;
} mirror_child_t;
typedef struct mirror_map {
int mm_children;
int mm_resilvering;
int mm_preferred;
int mm_root;
mirror_child_t mm_child[1];
} mirror_map_t;
int vdev_mirror_shift = 21;
static void
vdev_mirror_map_free(zio_t *zio)
{
mirror_map_t *mm = zio->io_vsd;
kmem_free(mm, offsetof(mirror_map_t, mm_child[mm->mm_children]));
}
static const zio_vsd_ops_t vdev_mirror_vsd_ops = {
vdev_mirror_map_free,
zio_vsd_default_cksum_report
};
static mirror_map_t *
vdev_mirror_map_alloc(zio_t *zio)
{
mirror_map_t *mm = NULL;
mirror_child_t *mc;
vdev_t *vd = zio->io_vd;
int c, d;
if (vd == NULL) {
dva_t *dva = zio->io_bp->blk_dva;
spa_t *spa = zio->io_spa;
dva_t dva_copy[SPA_DVAS_PER_BP];
c = BP_GET_NDVAS(zio->io_bp);
/*
* If we do not trust the pool config, some DVAs might be
* invalid or point to vdevs that do not exist. We skip them.
*/
if (!spa_trust_config(spa)) {
ASSERT3U(zio->io_type, ==, ZIO_TYPE_READ);
int j = 0;
for (int i = 0; i < c; i++) {
if (zfs_dva_valid(spa, &dva[i], zio->io_bp))
dva_copy[j++] = dva[i];
}
if (j == 0) {
zio->io_vsd = NULL;
zio->io_error = ENXIO;
return (NULL);
}
if (j < c) {
dva = dva_copy;
c = j;
}
}
mm = kmem_zalloc(offsetof(mirror_map_t, mm_child[c]), KM_SLEEP);
mm->mm_children = c;
mm->mm_resilvering = B_FALSE;
mm->mm_preferred = spa_get_random(c);
mm->mm_root = B_TRUE;
/*
* Check the other, lower-index DVAs to see if they're on
* the same vdev as the child we picked. If they are, use
* them since they are likely to have been allocated from
* the primary metaslab in use at the time, and hence are
* more likely to have locality with single-copy data.
*/
for (c = mm->mm_preferred, d = c - 1; d >= 0; d--) {
if (DVA_GET_VDEV(&dva[d]) == DVA_GET_VDEV(&dva[c]))
mm->mm_preferred = d;
}
for (c = 0; c < mm->mm_children; c++) {
mc = &mm->mm_child[c];
mc->mc_vd = vdev_lookup_top(spa, DVA_GET_VDEV(&dva[c]));
mc->mc_offset = DVA_GET_OFFSET(&dva[c]);
}
} else {
int replacing;
c = vd->vdev_children;
mm = kmem_zalloc(offsetof(mirror_map_t, mm_child[c]), KM_SLEEP);
mm->mm_children = c;
/*
* If we are resilvering, then we should handle scrub reads
* differently; we shouldn't issue them to the resilvering
* device because it might not have those blocks.
*
* We are resilvering iff:
* 1) We are a replacing vdev (ie our name is "replacing-1" or
* "spare-1" or something like that), and
* 2) The pool is currently being resilvered.
*
* We cannot simply check vd->vdev_resilver_txg, because it's
* not set in this path.
*
* Nor can we just check our vdev_ops; there are cases (such as
* when a user types "zpool replace pool odev spare_dev" and
* spare_dev is in the spare list, or when a spare device is
* automatically used to replace a DEGRADED device) when
* resilvering is complete but both the original vdev and the
* spare vdev remain in the pool. That behavior is intentional.
* It helps implement the policy that a spare should be
* automatically removed from the pool after the user replaces
* the device that originally failed.
*/
replacing = (vd->vdev_ops == &vdev_replacing_ops ||
vd->vdev_ops == &vdev_spare_ops);
/*
* If a spa load is in progress, then spa_dsl_pool may be
* uninitialized. But we shouldn't be resilvering during a spa
* load anyway.
*/
if (replacing &&
(spa_load_state(vd->vdev_spa) == SPA_LOAD_NONE) &&
dsl_scan_resilvering(vd->vdev_spa->spa_dsl_pool)) {
mm->mm_resilvering = B_TRUE;
} else {
mm->mm_resilvering = B_FALSE;
}
mm->mm_preferred = mm->mm_resilvering ? 0 :
(zio->io_offset >> vdev_mirror_shift) % c;
mm->mm_root = B_FALSE;
for (c = 0; c < mm->mm_children; c++) {
mc = &mm->mm_child[c];
mc->mc_vd = vd->vdev_child[c];
mc->mc_offset = zio->io_offset;
}
}
zio->io_vsd = mm;
zio->io_vsd_ops = &vdev_mirror_vsd_ops;
return (mm);
}
static int
vdev_mirror_open(vdev_t *vd, uint64_t *asize, uint64_t *max_asize,
uint64_t *ashift)
{
int numerrors = 0;
int lasterror = 0;
if (vd->vdev_children == 0) {
vd->vdev_stat.vs_aux = VDEV_AUX_BAD_LABEL;
return (SET_ERROR(EINVAL));
}
vdev_open_children(vd);
for (int c = 0; c < vd->vdev_children; c++) {
vdev_t *cvd = vd->vdev_child[c];
if (cvd->vdev_open_error) {
lasterror = cvd->vdev_open_error;
numerrors++;
continue;
}
*asize = MIN(*asize - 1, cvd->vdev_asize - 1) + 1;
*max_asize = MIN(*max_asize - 1, cvd->vdev_max_asize - 1) + 1;
*ashift = MAX(*ashift, cvd->vdev_ashift);
}
if (numerrors == vd->vdev_children) {
if (vdev_children_are_offline(vd))
vd->vdev_stat.vs_aux = VDEV_AUX_CHILDREN_OFFLINE;
else
vd->vdev_stat.vs_aux = VDEV_AUX_NO_REPLICAS;
return (lasterror);
}
return (0);
}
static void
vdev_mirror_close(vdev_t *vd)
{
for (int c = 0; c < vd->vdev_children; c++)
vdev_close(vd->vdev_child[c]);
}
static void
vdev_mirror_child_done(zio_t *zio)
{
mirror_child_t *mc = zio->io_private;
mc->mc_error = zio->io_error;
mc->mc_tried = 1;
mc->mc_skipped = 0;
}
static void
vdev_mirror_scrub_done(zio_t *zio)
{
mirror_child_t *mc = zio->io_private;
if (zio->io_error == 0) {
zio_t *pio;
zio_link_t *zl = NULL;
mutex_enter(&zio->io_lock);
while ((pio = zio_walk_parents(zio, &zl)) != NULL) {
mutex_enter(&pio->io_lock);
ASSERT3U(zio->io_size, >=, pio->io_size);
abd_copy(pio->io_abd, zio->io_abd, pio->io_size);
mutex_exit(&pio->io_lock);
}
mutex_exit(&zio->io_lock);
}
abd_free(zio->io_abd);
mc->mc_error = zio->io_error;
mc->mc_tried = 1;
mc->mc_skipped = 0;
}
/*
* Try to find a child whose DTL doesn't contain the block we want to read.
* If we can't, try the read on any vdev we haven't already tried.
*/
static int
vdev_mirror_child_select(zio_t *zio)
{
mirror_map_t *mm = zio->io_vsd;
mirror_child_t *mc;
uint64_t txg = zio->io_txg;
int i, c;
ASSERT(zio->io_bp == NULL || BP_PHYSICAL_BIRTH(zio->io_bp) == txg);
/*
* Try to find a child whose DTL doesn't contain the block to read.
* If a child is known to be completely inaccessible (indicated by
* vdev_readable() returning B_FALSE), don't even try.
*/
for (i = 0, c = mm->mm_preferred; i < mm->mm_children; i++, c++) {
if (c >= mm->mm_children)
c = 0;
mc = &mm->mm_child[c];
if (mc->mc_tried || mc->mc_skipped)
continue;
if (!vdev_readable(mc->mc_vd)) {
mc->mc_error = SET_ERROR(ENXIO);
mc->mc_tried = 1; /* don't even try */
mc->mc_skipped = 1;
continue;
}
if (!vdev_dtl_contains(mc->mc_vd, DTL_MISSING, txg, 1))
return (c);
mc->mc_error = SET_ERROR(ESTALE);
mc->mc_skipped = 1;
mc->mc_speculative = 1;
}
/*
* Every device is either missing or has this txg in its DTL.
* Look for any child we haven't already tried before giving up.
*/
for (c = 0; c < mm->mm_children; c++)
if (!mm->mm_child[c].mc_tried)
return (c);
/*
* Every child failed. There's no place left to look.
*/
return (-1);
}
static void
vdev_mirror_io_start(zio_t *zio)
{
mirror_map_t *mm;
mirror_child_t *mc;
int c, children;
mm = vdev_mirror_map_alloc(zio);
if (mm == NULL) {
ASSERT(!spa_trust_config(zio->io_spa));
ASSERT(zio->io_type == ZIO_TYPE_READ);
zio_execute(zio);
return;
}
if (zio->io_type == ZIO_TYPE_READ) {
if (zio->io_bp != NULL &&
(zio->io_flags & ZIO_FLAG_SCRUB) && !mm->mm_resilvering) {
/*
* For scrubbing reads (if we can verify the
* checksum here, as indicated by io_bp being
* non-NULL) we need to allocate a read buffer for
* each child and issue reads to all children. If
* any child succeeds, it will copy its data into
* zio->io_data in vdev_mirror_scrub_done.
*/
for (c = 0; c < mm->mm_children; c++) {
mc = &mm->mm_child[c];
zio_nowait(zio_vdev_child_io(zio, zio->io_bp,
mc->mc_vd, mc->mc_offset,
abd_alloc_sametype(zio->io_abd,
zio->io_size), zio->io_size,
zio->io_type, zio->io_priority, 0,
vdev_mirror_scrub_done, mc));
}
zio_execute(zio);
return;
}
/*
* For normal reads just pick one child.
*/
c = vdev_mirror_child_select(zio);
children = (c >= 0);
} else {
ASSERT(zio->io_type == ZIO_TYPE_WRITE);
/*
* Writes go to all children.
*/
c = 0;
children = mm->mm_children;
}
while (children--) {
mc = &mm->mm_child[c];
zio_nowait(zio_vdev_child_io(zio, zio->io_bp,
mc->mc_vd, mc->mc_offset, zio->io_abd, zio->io_size,
zio->io_type, zio->io_priority, 0,
vdev_mirror_child_done, mc));
c++;
}
zio_execute(zio);
}
static int
vdev_mirror_worst_error(mirror_map_t *mm)
{
int error[2] = { 0, 0 };
for (int c = 0; c < mm->mm_children; c++) {
mirror_child_t *mc = &mm->mm_child[c];
int s = mc->mc_speculative;
error[s] = zio_worst_error(error[s], mc->mc_error);
}
return (error[0] ? error[0] : error[1]);
}
static void
vdev_mirror_io_done(zio_t *zio)
{
mirror_map_t *mm = zio->io_vsd;
mirror_child_t *mc;
int c;
int good_copies = 0;
int unexpected_errors = 0;
if (mm == NULL)
return;
for (c = 0; c < mm->mm_children; c++) {
mc = &mm->mm_child[c];
if (mc->mc_error) {
if (!mc->mc_skipped)
unexpected_errors++;
} else if (mc->mc_tried) {
good_copies++;
}
}
if (zio->io_type == ZIO_TYPE_WRITE) {
/*
* XXX -- for now, treat partial writes as success.
*
* Now that we support write reallocation, it would be better
* to treat partial failure as real failure unless there are
* no non-degraded top-level vdevs left, and not update DTLs
* if we intend to reallocate.
*/
/* XXPOLICY */
if (good_copies != mm->mm_children) {
/*
* Always require at least one good copy.
*
* For ditto blocks (io_vd == NULL), require
* all copies to be good.
*
* XXX -- for replacing vdevs, there's no great answer.
* If the old device is really dead, we may not even
* be able to access it -- so we only want to
* require good writes to the new device. But if
* the new device turns out to be flaky, we want
* to be able to detach it -- which requires all
* writes to the old device to have succeeded.
*/
if (good_copies == 0 || zio->io_vd == NULL)
zio->io_error = vdev_mirror_worst_error(mm);
}
return;
}
ASSERT(zio->io_type == ZIO_TYPE_READ);
/*
* If we don't have a good copy yet, keep trying other children.
*/
/* XXPOLICY */
if (good_copies == 0 && (c = vdev_mirror_child_select(zio)) != -1) {
ASSERT(c >= 0 && c < mm->mm_children);
mc = &mm->mm_child[c];
zio_vdev_io_redone(zio);
zio_nowait(zio_vdev_child_io(zio, zio->io_bp,
mc->mc_vd, mc->mc_offset, zio->io_abd, zio->io_size,
ZIO_TYPE_READ, zio->io_priority, 0,
vdev_mirror_child_done, mc));
return;
}
/* XXPOLICY */
if (good_copies == 0) {
zio->io_error = vdev_mirror_worst_error(mm);
ASSERT(zio->io_error != 0);
}
if (good_copies && spa_writeable(zio->io_spa) &&
(unexpected_errors ||
(zio->io_flags & ZIO_FLAG_RESILVER) ||
((zio->io_flags & ZIO_FLAG_SCRUB) && mm->mm_resilvering))) {
/*
* Use the good data we have in hand to repair damaged children.
*/
for (c = 0; c < mm->mm_children; c++) {
/*
* Don't rewrite known good children.
* Not only is it unnecessary, it could
* actually be harmful: if the system lost
* power while rewriting the only good copy,
* there would be no good copies left!
*/
mc = &mm->mm_child[c];
if (mc->mc_error == 0) {
if (mc->mc_tried)
continue;
/*
* We didn't try this child. We need to
* repair it if:
* 1. it's a scrub (in which case we have
* tried everything that was healthy)
* - or -
* 2. it's an indirect vdev (in which case
* it could point to any other vdev, which
* might have a bad DTL)
* - or -
* 3. the DTL indicates that this data is
* missing from this vdev
*/
if (!(zio->io_flags & ZIO_FLAG_SCRUB) &&
mc->mc_vd->vdev_ops != &vdev_indirect_ops &&
!vdev_dtl_contains(mc->mc_vd, DTL_PARTIAL,
zio->io_txg, 1))
continue;
mc->mc_error = SET_ERROR(ESTALE);
}
zio_nowait(zio_vdev_child_io(zio, zio->io_bp,
mc->mc_vd, mc->mc_offset,
zio->io_abd, zio->io_size,
ZIO_TYPE_WRITE, ZIO_PRIORITY_ASYNC_WRITE,
ZIO_FLAG_IO_REPAIR | (unexpected_errors ?
ZIO_FLAG_SELF_HEAL : 0), NULL, NULL));
}
}
}
static void
vdev_mirror_state_change(vdev_t *vd, int faulted, int degraded)
{
if (faulted == vd->vdev_children) {
if (vdev_children_are_offline(vd)) {
vdev_set_state(vd, B_FALSE, VDEV_STATE_OFFLINE,
VDEV_AUX_CHILDREN_OFFLINE);
} else {
vdev_set_state(vd, B_FALSE, VDEV_STATE_CANT_OPEN,
VDEV_AUX_NO_REPLICAS);
}
} else if (degraded + faulted != 0) {
vdev_set_state(vd, B_FALSE, VDEV_STATE_DEGRADED, VDEV_AUX_NONE);
} else {
vdev_set_state(vd, B_FALSE, VDEV_STATE_HEALTHY, VDEV_AUX_NONE);
}
}
vdev_ops_t vdev_mirror_ops = {
vdev_mirror_open,
vdev_mirror_close,
vdev_default_asize,
vdev_mirror_io_start,
vdev_mirror_io_done,
vdev_mirror_state_change,
NULL,
NULL,
NULL,
vdev_default_xlate,
VDEV_TYPE_MIRROR, /* name of this vdev type */
B_FALSE /* not a leaf vdev */
};
vdev_ops_t vdev_replacing_ops = {
vdev_mirror_open,
vdev_mirror_close,
vdev_default_asize,
vdev_mirror_io_start,
vdev_mirror_io_done,
vdev_mirror_state_change,
NULL,
NULL,
NULL,
vdev_default_xlate,
VDEV_TYPE_REPLACING, /* name of this vdev type */
B_FALSE /* not a leaf vdev */
};
vdev_ops_t vdev_spare_ops = {
vdev_mirror_open,
vdev_mirror_close,
vdev_default_asize,
vdev_mirror_io_start,
vdev_mirror_io_done,
vdev_mirror_state_change,
NULL,
NULL,
NULL,
vdev_default_xlate,
VDEV_TYPE_SPARE, /* name of this vdev type */
B_FALSE /* not a leaf vdev */
};