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-rw-r--r--uts/common/fs/zfs/vdev_mirror.c485
1 files changed, 485 insertions, 0 deletions
diff --git a/uts/common/fs/zfs/vdev_mirror.c b/uts/common/fs/zfs/vdev_mirror.c
new file mode 100644
index 000000000000..698c0275d34e
--- /dev/null
+++ b/uts/common/fs/zfs/vdev_mirror.c
@@ -0,0 +1,485 @@
+/*
+ * 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.
+ */
+
+#include <sys/zfs_context.h>
+#include <sys/spa.h>
+#include <sys/vdev_impl.h>
+#include <sys/zio.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_replacing;
+ 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;
+
+ c = BP_GET_NDVAS(zio->io_bp);
+
+ mm = kmem_zalloc(offsetof(mirror_map_t, mm_child[c]), KM_SLEEP);
+ mm->mm_children = c;
+ mm->mm_replacing = 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 {
+ c = vd->vdev_children;
+
+ mm = kmem_zalloc(offsetof(mirror_map_t, mm_child[c]), KM_SLEEP);
+ mm->mm_children = c;
+ mm->mm_replacing = (vd->vdev_ops == &vdev_replacing_ops ||
+ vd->vdev_ops == &vdev_spare_ops);
+ mm->mm_preferred = mm->mm_replacing ? 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 *ashift)
+{
+ int numerrors = 0;
+ int lasterror = 0;
+
+ if (vd->vdev_children == 0) {
+ vd->vdev_stat.vs_aux = VDEV_AUX_BAD_LABEL;
+ return (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;
+ *ashift = MAX(*ashift, cvd->vdev_ashift);
+ }
+
+ if (numerrors == vd->vdev_children) {
+ 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;
+
+ mutex_enter(&zio->io_lock);
+ while ((pio = zio_walk_parents(zio)) != NULL) {
+ mutex_enter(&pio->io_lock);
+ ASSERT3U(zio->io_size, >=, pio->io_size);
+ bcopy(zio->io_data, pio->io_data, pio->io_size);
+ mutex_exit(&pio->io_lock);
+ }
+ mutex_exit(&zio->io_lock);
+ }
+
+ zio_buf_free(zio->io_data, zio->io_size);
+
+ 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 = 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 = 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 int
+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 (zio->io_type == ZIO_TYPE_READ) {
+ if ((zio->io_flags & ZIO_FLAG_SCRUB) && !mm->mm_replacing) {
+ /*
+ * For scrubbing reads 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,
+ zio_buf_alloc(zio->io_size), zio->io_size,
+ zio->io_type, zio->io_priority, 0,
+ vdev_mirror_scrub_done, mc));
+ }
+ return (ZIO_PIPELINE_CONTINUE);
+ }
+ /*
+ * 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_data, zio->io_size,
+ zio->io_type, zio->io_priority, 0,
+ vdev_mirror_child_done, mc));
+ c++;
+ }
+
+ return (ZIO_PIPELINE_CONTINUE);
+}
+
+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;
+
+ 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_data, 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_replacing))) {
+ /*
+ * 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;
+ if (!(zio->io_flags & ZIO_FLAG_SCRUB) &&
+ !vdev_dtl_contains(mc->mc_vd, DTL_PARTIAL,
+ zio->io_txg, 1))
+ continue;
+ mc->mc_error = ESTALE;
+ }
+
+ zio_nowait(zio_vdev_child_io(zio, zio->io_bp,
+ mc->mc_vd, mc->mc_offset,
+ zio->io_data, zio->io_size,
+ ZIO_TYPE_WRITE, zio->io_priority,
+ 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)
+ 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,
+ 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,
+ 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,
+ VDEV_TYPE_SPARE, /* name of this vdev type */
+ B_FALSE /* not a leaf vdev */
+};