478 lines
12 KiB
C
478 lines
12 KiB
C
/*
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* CDDL HEADER START
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*
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* The contents of this file are subject to the terms of the
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* Common Development and Distribution License (the "License").
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* You may not use this file except in compliance with the License.
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*
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* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
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* or http://www.opensolaris.org/os/licensing.
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* See the License for the specific language governing permissions
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* and limitations under the License.
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*
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* When distributing Covered Code, include this CDDL HEADER in each
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* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
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* If applicable, add the following below this CDDL HEADER, with the
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* fields enclosed by brackets "[]" replaced with your own identifying
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* information: Portions Copyright [yyyy] [name of copyright owner]
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*
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* CDDL HEADER END
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*/
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/*
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* Copyright 2009 Sun Microsystems, Inc. All rights reserved.
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* Use is subject to license terms.
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*/
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#include <sys/zfs_context.h>
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#include <sys/spa.h>
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#include <sys/vdev_impl.h>
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#include <sys/zio.h>
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#include <sys/fs/zfs.h>
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/*
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* Virtual device vector for mirroring.
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*/
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typedef struct mirror_child {
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vdev_t *mc_vd;
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uint64_t mc_offset;
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int mc_error;
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uint8_t mc_tried;
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uint8_t mc_skipped;
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uint8_t mc_speculative;
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} mirror_child_t;
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typedef struct mirror_map {
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int mm_children;
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int mm_replacing;
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int mm_preferred;
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int mm_root;
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mirror_child_t mm_child[1];
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} mirror_map_t;
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int vdev_mirror_shift = 21;
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static void
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vdev_mirror_map_free(zio_t *zio)
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{
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mirror_map_t *mm = zio->io_vsd;
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kmem_free(mm, offsetof(mirror_map_t, mm_child[mm->mm_children]));
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}
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static mirror_map_t *
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vdev_mirror_map_alloc(zio_t *zio)
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{
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mirror_map_t *mm = NULL;
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mirror_child_t *mc;
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vdev_t *vd = zio->io_vd;
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int c, d;
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if (vd == NULL) {
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dva_t *dva = zio->io_bp->blk_dva;
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spa_t *spa = zio->io_spa;
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c = BP_GET_NDVAS(zio->io_bp);
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mm = kmem_zalloc(offsetof(mirror_map_t, mm_child[c]), KM_SLEEP);
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mm->mm_children = c;
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mm->mm_replacing = B_FALSE;
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mm->mm_preferred = spa_get_random(c);
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mm->mm_root = B_TRUE;
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/*
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* Check the other, lower-index DVAs to see if they're on
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* the same vdev as the child we picked. If they are, use
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* them since they are likely to have been allocated from
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* the primary metaslab in use at the time, and hence are
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* more likely to have locality with single-copy data.
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*/
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for (c = mm->mm_preferred, d = c - 1; d >= 0; d--) {
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if (DVA_GET_VDEV(&dva[d]) == DVA_GET_VDEV(&dva[c]))
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mm->mm_preferred = d;
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}
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for (c = 0; c < mm->mm_children; c++) {
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mc = &mm->mm_child[c];
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mc->mc_vd = vdev_lookup_top(spa, DVA_GET_VDEV(&dva[c]));
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mc->mc_offset = DVA_GET_OFFSET(&dva[c]);
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}
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} else {
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c = vd->vdev_children;
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mm = kmem_zalloc(offsetof(mirror_map_t, mm_child[c]), KM_SLEEP);
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mm->mm_children = c;
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mm->mm_replacing = (vd->vdev_ops == &vdev_replacing_ops ||
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vd->vdev_ops == &vdev_spare_ops);
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mm->mm_preferred = mm->mm_replacing ? 0 :
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(zio->io_offset >> vdev_mirror_shift) % c;
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mm->mm_root = B_FALSE;
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for (c = 0; c < mm->mm_children; c++) {
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mc = &mm->mm_child[c];
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mc->mc_vd = vd->vdev_child[c];
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mc->mc_offset = zio->io_offset;
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}
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}
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zio->io_vsd = mm;
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zio->io_vsd_free = vdev_mirror_map_free;
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return (mm);
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}
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static int
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vdev_mirror_open(vdev_t *vd, uint64_t *asize, uint64_t *ashift)
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{
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int numerrors = 0;
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int lasterror = 0;
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int c;
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if (vd->vdev_children == 0) {
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vd->vdev_stat.vs_aux = VDEV_AUX_BAD_LABEL;
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return (EINVAL);
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}
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vdev_open_children(vd);
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for (c = 0; c < vd->vdev_children; c++) {
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vdev_t *cvd = vd->vdev_child[c];
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if (cvd->vdev_open_error) {
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lasterror = cvd->vdev_open_error;
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numerrors++;
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continue;
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}
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*asize = MIN(*asize - 1, cvd->vdev_asize - 1) + 1;
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*ashift = MAX(*ashift, cvd->vdev_ashift);
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}
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if (numerrors == vd->vdev_children) {
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vd->vdev_stat.vs_aux = VDEV_AUX_NO_REPLICAS;
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return (lasterror);
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}
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return (0);
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}
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static void
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vdev_mirror_close(vdev_t *vd)
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{
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int c;
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for (c = 0; c < vd->vdev_children; c++)
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vdev_close(vd->vdev_child[c]);
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}
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static void
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vdev_mirror_child_done(zio_t *zio)
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{
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mirror_child_t *mc = zio->io_private;
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mc->mc_error = zio->io_error;
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mc->mc_tried = 1;
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mc->mc_skipped = 0;
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}
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static void
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vdev_mirror_scrub_done(zio_t *zio)
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{
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mirror_child_t *mc = zio->io_private;
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if (zio->io_error == 0) {
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zio_t *pio;
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mutex_enter(&zio->io_lock);
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while ((pio = zio_walk_parents(zio)) != NULL) {
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mutex_enter(&pio->io_lock);
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ASSERT3U(zio->io_size, >=, pio->io_size);
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bcopy(zio->io_data, pio->io_data, pio->io_size);
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mutex_exit(&pio->io_lock);
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}
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mutex_exit(&zio->io_lock);
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}
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zio_buf_free(zio->io_data, zio->io_size);
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mc->mc_error = zio->io_error;
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mc->mc_tried = 1;
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mc->mc_skipped = 0;
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}
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/*
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* Try to find a child whose DTL doesn't contain the block we want to read.
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* If we can't, try the read on any vdev we haven't already tried.
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*/
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static int
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vdev_mirror_child_select(zio_t *zio)
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{
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mirror_map_t *mm = zio->io_vsd;
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mirror_child_t *mc;
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uint64_t txg = zio->io_txg;
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int i, c;
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ASSERT(zio->io_bp == NULL || zio->io_bp->blk_birth == txg);
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/*
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* Try to find a child whose DTL doesn't contain the block to read.
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* If a child is known to be completely inaccessible (indicated by
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* vdev_readable() returning B_FALSE), don't even try.
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*/
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for (i = 0, c = mm->mm_preferred; i < mm->mm_children; i++, c++) {
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if (c >= mm->mm_children)
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c = 0;
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mc = &mm->mm_child[c];
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if (mc->mc_tried || mc->mc_skipped)
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continue;
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if (!vdev_readable(mc->mc_vd)) {
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mc->mc_error = ENXIO;
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mc->mc_tried = 1; /* don't even try */
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mc->mc_skipped = 1;
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continue;
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}
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if (!vdev_dtl_contains(mc->mc_vd, DTL_MISSING, txg, 1))
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return (c);
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mc->mc_error = ESTALE;
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mc->mc_skipped = 1;
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mc->mc_speculative = 1;
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}
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/*
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* Every device is either missing or has this txg in its DTL.
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* Look for any child we haven't already tried before giving up.
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*/
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for (c = 0; c < mm->mm_children; c++)
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if (!mm->mm_child[c].mc_tried)
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return (c);
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/*
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* Every child failed. There's no place left to look.
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*/
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return (-1);
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}
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static int
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vdev_mirror_io_start(zio_t *zio)
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{
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mirror_map_t *mm;
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mirror_child_t *mc;
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int c, children;
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mm = vdev_mirror_map_alloc(zio);
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if (zio->io_type == ZIO_TYPE_READ) {
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if ((zio->io_flags & ZIO_FLAG_SCRUB) && !mm->mm_replacing) {
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/*
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* For scrubbing reads we need to allocate a read
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* buffer for each child and issue reads to all
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* children. If any child succeeds, it will copy its
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* data into zio->io_data in vdev_mirror_scrub_done.
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*/
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for (c = 0; c < mm->mm_children; c++) {
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mc = &mm->mm_child[c];
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zio_nowait(zio_vdev_child_io(zio, zio->io_bp,
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mc->mc_vd, mc->mc_offset,
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zio_buf_alloc(zio->io_size), zio->io_size,
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zio->io_type, zio->io_priority, 0,
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vdev_mirror_scrub_done, mc));
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}
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return (ZIO_PIPELINE_CONTINUE);
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}
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/*
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* For normal reads just pick one child.
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*/
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c = vdev_mirror_child_select(zio);
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children = (c >= 0);
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} else {
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ASSERT(zio->io_type == ZIO_TYPE_WRITE);
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/*
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* Writes go to all children.
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*/
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c = 0;
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children = mm->mm_children;
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}
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while (children--) {
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mc = &mm->mm_child[c];
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zio_nowait(zio_vdev_child_io(zio, zio->io_bp,
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mc->mc_vd, mc->mc_offset, zio->io_data, zio->io_size,
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zio->io_type, zio->io_priority, 0,
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vdev_mirror_child_done, mc));
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c++;
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}
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return (ZIO_PIPELINE_CONTINUE);
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}
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static int
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vdev_mirror_worst_error(mirror_map_t *mm)
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{
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int c, error[2] = { 0, 0 };
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for (c = 0; c < mm->mm_children; c++) {
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mirror_child_t *mc = &mm->mm_child[c];
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int s = mc->mc_speculative;
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error[s] = zio_worst_error(error[s], mc->mc_error);
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}
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return (error[0] ? error[0] : error[1]);
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}
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static void
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vdev_mirror_io_done(zio_t *zio)
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{
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mirror_map_t *mm = zio->io_vsd;
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mirror_child_t *mc;
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int c;
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int good_copies = 0;
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int unexpected_errors = 0;
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for (c = 0; c < mm->mm_children; c++) {
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mc = &mm->mm_child[c];
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if (mc->mc_error) {
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if (!mc->mc_skipped)
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unexpected_errors++;
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} else if (mc->mc_tried) {
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good_copies++;
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}
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}
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if (zio->io_type == ZIO_TYPE_WRITE) {
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/*
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* XXX -- for now, treat partial writes as success.
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*
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* Now that we support write reallocation, it would be better
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* to treat partial failure as real failure unless there are
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* no non-degraded top-level vdevs left, and not update DTLs
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* if we intend to reallocate.
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*/
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/* XXPOLICY */
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if (good_copies != mm->mm_children) {
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/*
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* Always require at least one good copy.
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*
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* For ditto blocks (io_vd == NULL), require
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* all copies to be good.
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*
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* XXX -- for replacing vdevs, there's no great answer.
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* If the old device is really dead, we may not even
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* be able to access it -- so we only want to
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* require good writes to the new device. But if
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* the new device turns out to be flaky, we want
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* to be able to detach it -- which requires all
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* writes to the old device to have succeeded.
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*/
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if (good_copies == 0 || zio->io_vd == NULL)
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zio->io_error = vdev_mirror_worst_error(mm);
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}
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return;
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}
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ASSERT(zio->io_type == ZIO_TYPE_READ);
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/*
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* If we don't have a good copy yet, keep trying other children.
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*/
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/* XXPOLICY */
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if (good_copies == 0 && (c = vdev_mirror_child_select(zio)) != -1) {
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ASSERT(c >= 0 && c < mm->mm_children);
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mc = &mm->mm_child[c];
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zio_vdev_io_redone(zio);
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zio_nowait(zio_vdev_child_io(zio, zio->io_bp,
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mc->mc_vd, mc->mc_offset, zio->io_data, zio->io_size,
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ZIO_TYPE_READ, zio->io_priority, 0,
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vdev_mirror_child_done, mc));
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return;
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}
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/* XXPOLICY */
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if (good_copies == 0) {
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zio->io_error = vdev_mirror_worst_error(mm);
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ASSERT(zio->io_error != 0);
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}
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if (good_copies && spa_writeable(zio->io_spa) &&
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(unexpected_errors ||
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(zio->io_flags & ZIO_FLAG_RESILVER) ||
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((zio->io_flags & ZIO_FLAG_SCRUB) && mm->mm_replacing))) {
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/*
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* Use the good data we have in hand to repair damaged children.
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*/
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for (c = 0; c < mm->mm_children; c++) {
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/*
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* Don't rewrite known good children.
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* Not only is it unnecessary, it could
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* actually be harmful: if the system lost
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* power while rewriting the only good copy,
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* there would be no good copies left!
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*/
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mc = &mm->mm_child[c];
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if (mc->mc_error == 0) {
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if (mc->mc_tried)
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continue;
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if (!(zio->io_flags & ZIO_FLAG_SCRUB) &&
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!vdev_dtl_contains(mc->mc_vd, DTL_PARTIAL,
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zio->io_txg, 1))
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continue;
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mc->mc_error = ESTALE;
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}
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zio_nowait(zio_vdev_child_io(zio, zio->io_bp,
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mc->mc_vd, mc->mc_offset,
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zio->io_data, zio->io_size,
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ZIO_TYPE_WRITE, zio->io_priority,
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ZIO_FLAG_IO_REPAIR | (unexpected_errors ?
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ZIO_FLAG_SELF_HEAL : 0), NULL, NULL));
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}
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}
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}
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static void
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vdev_mirror_state_change(vdev_t *vd, int faulted, int degraded)
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{
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if (faulted == vd->vdev_children)
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vdev_set_state(vd, B_FALSE, VDEV_STATE_CANT_OPEN,
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VDEV_AUX_NO_REPLICAS);
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else if (degraded + faulted != 0)
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vdev_set_state(vd, B_FALSE, VDEV_STATE_DEGRADED, VDEV_AUX_NONE);
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else
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vdev_set_state(vd, B_FALSE, VDEV_STATE_HEALTHY, VDEV_AUX_NONE);
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}
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vdev_ops_t vdev_mirror_ops = {
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vdev_mirror_open,
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vdev_mirror_close,
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vdev_default_asize,
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vdev_mirror_io_start,
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vdev_mirror_io_done,
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vdev_mirror_state_change,
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VDEV_TYPE_MIRROR, /* name of this vdev type */
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B_FALSE /* not a leaf vdev */
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};
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vdev_ops_t vdev_replacing_ops = {
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vdev_mirror_open,
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vdev_mirror_close,
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vdev_default_asize,
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vdev_mirror_io_start,
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vdev_mirror_io_done,
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vdev_mirror_state_change,
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VDEV_TYPE_REPLACING, /* name of this vdev type */
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B_FALSE /* not a leaf vdev */
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};
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vdev_ops_t vdev_spare_ops = {
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vdev_mirror_open,
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vdev_mirror_close,
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vdev_default_asize,
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vdev_mirror_io_start,
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vdev_mirror_io_done,
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vdev_mirror_state_change,
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VDEV_TYPE_SPARE, /* name of this vdev type */
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B_FALSE /* not a leaf vdev */
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};
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