/* * 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, 2015 by Delphix. All rights reserved. */ #include #include #include #include #include #include /* * Vdev mirror kstats */ static kstat_t *mirror_ksp = NULL; typedef struct mirror_stats { kstat_named_t vdev_mirror_stat_rotating_linear; kstat_named_t vdev_mirror_stat_rotating_offset; kstat_named_t vdev_mirror_stat_rotating_seek; kstat_named_t vdev_mirror_stat_non_rotating_linear; kstat_named_t vdev_mirror_stat_non_rotating_seek; kstat_named_t vdev_mirror_stat_preferred_found; kstat_named_t vdev_mirror_stat_preferred_not_found; } mirror_stats_t; static mirror_stats_t mirror_stats = { /* New I/O follows directly the last I/O */ { "rotating_linear", KSTAT_DATA_UINT64 }, /* New I/O is within zfs_vdev_mirror_rotating_seek_offset of the last */ { "rotating_offset", KSTAT_DATA_UINT64 }, /* New I/O requires random seek */ { "rotating_seek", KSTAT_DATA_UINT64 }, /* New I/O follows directly the last I/O (nonrot) */ { "non_rotating_linear", KSTAT_DATA_UINT64 }, /* New I/O requires random seek (nonrot) */ { "non_rotating_seek", KSTAT_DATA_UINT64 }, /* Preferred child vdev found */ { "preferred_found", KSTAT_DATA_UINT64 }, /* Preferred child vdev not found or equal load */ { "preferred_not_found", KSTAT_DATA_UINT64 }, }; #define MIRROR_STAT(stat) (mirror_stats.stat.value.ui64) #define MIRROR_INCR(stat, val) atomic_add_64(&MIRROR_STAT(stat), val) #define MIRROR_BUMP(stat) MIRROR_INCR(stat, 1) void vdev_mirror_stat_init(void) { mirror_ksp = kstat_create("zfs", 0, "vdev_mirror_stats", "misc", KSTAT_TYPE_NAMED, sizeof (mirror_stats) / sizeof (kstat_named_t), KSTAT_FLAG_VIRTUAL); if (mirror_ksp != NULL) { mirror_ksp->ks_data = &mirror_stats; kstat_install(mirror_ksp); } } void vdev_mirror_stat_fini(void) { if (mirror_ksp != NULL) { kstat_delete(mirror_ksp); mirror_ksp = NULL; } } /* * Virtual device vector for mirroring. */ typedef struct mirror_child { vdev_t *mc_vd; uint64_t mc_offset; int mc_error; int mc_load; uint8_t mc_tried; uint8_t mc_skipped; uint8_t mc_speculative; } mirror_child_t; typedef struct mirror_map { int *mm_preferred; int mm_preferred_cnt; int mm_children; boolean_t mm_replacing; boolean_t mm_root; mirror_child_t mm_child[]; } mirror_map_t; static int vdev_mirror_shift = 21; /* * The load configuration settings below are tuned by default for * the case where all devices are of the same rotational type. * * If there is a mixture of rotating and non-rotating media, setting * zfs_vdev_mirror_non_rotating_seek_inc to 0 may well provide better results * as it will direct more reads to the non-rotating vdevs which are more likely * to have a higher performance. */ /* Rotating media load calculation configuration. */ static int zfs_vdev_mirror_rotating_inc = 0; static int zfs_vdev_mirror_rotating_seek_inc = 5; static int zfs_vdev_mirror_rotating_seek_offset = 1 * 1024 * 1024; /* Non-rotating media load calculation configuration. */ static int zfs_vdev_mirror_non_rotating_inc = 0; static int zfs_vdev_mirror_non_rotating_seek_inc = 1; static inline size_t vdev_mirror_map_size(int children) { return (offsetof(mirror_map_t, mm_child[children]) + sizeof (int) * children); } static inline mirror_map_t * vdev_mirror_map_alloc(int children, boolean_t replacing, boolean_t root) { mirror_map_t *mm; mm = kmem_zalloc(vdev_mirror_map_size(children), KM_SLEEP); mm->mm_children = children; mm->mm_replacing = replacing; mm->mm_root = root; mm->mm_preferred = (int *)((uintptr_t)mm + offsetof(mirror_map_t, mm_child[children])); return (mm); } static void vdev_mirror_map_free(zio_t *zio) { mirror_map_t *mm = zio->io_vsd; kmem_free(mm, vdev_mirror_map_size(mm->mm_children)); } static const zio_vsd_ops_t vdev_mirror_vsd_ops = { .vsd_free = vdev_mirror_map_free, .vsd_cksum_report = zio_vsd_default_cksum_report }; static int vdev_mirror_load(mirror_map_t *mm, vdev_t *vd, uint64_t zio_offset) { uint64_t last_offset; int64_t offset_diff; int load; /* All DVAs have equal weight at the root. */ if (mm->mm_root) return (INT_MAX); /* * We don't return INT_MAX if the device is resilvering i.e. * vdev_resilver_txg != 0 as when tested performance was slightly * worse overall when resilvering with compared to without. */ /* Fix zio_offset for leaf vdevs */ if (vd->vdev_ops->vdev_op_leaf) zio_offset += VDEV_LABEL_START_SIZE; /* Standard load based on pending queue length. */ load = vdev_queue_length(vd); last_offset = vdev_queue_last_offset(vd); if (vd->vdev_nonrot) { /* Non-rotating media. */ if (last_offset == zio_offset) { MIRROR_BUMP(vdev_mirror_stat_non_rotating_linear); return (load + zfs_vdev_mirror_non_rotating_inc); } /* * Apply a seek penalty even for non-rotating devices as * sequential I/O's can be aggregated into fewer operations on * the device, thus avoiding unnecessary per-command overhead * and boosting performance. */ MIRROR_BUMP(vdev_mirror_stat_non_rotating_seek); return (load + zfs_vdev_mirror_non_rotating_seek_inc); } /* Rotating media I/O's which directly follow the last I/O. */ if (last_offset == zio_offset) { MIRROR_BUMP(vdev_mirror_stat_rotating_linear); return (load + zfs_vdev_mirror_rotating_inc); } /* * Apply half the seek increment to I/O's within seek offset * of the last I/O issued to this vdev as they should incur less * of a seek increment. */ offset_diff = (int64_t)(last_offset - zio_offset); if (ABS(offset_diff) < zfs_vdev_mirror_rotating_seek_offset) { MIRROR_BUMP(vdev_mirror_stat_rotating_offset); return (load + (zfs_vdev_mirror_rotating_seek_inc / 2)); } /* Apply the full seek increment to all other I/O's. */ MIRROR_BUMP(vdev_mirror_stat_rotating_seek); return (load + zfs_vdev_mirror_rotating_seek_inc); } /* * Avoid inlining the function to keep vdev_mirror_io_start(), which * is this functions only caller, as small as possible on the stack. */ noinline static mirror_map_t * vdev_mirror_map_init(zio_t *zio) { mirror_map_t *mm = NULL; mirror_child_t *mc; vdev_t *vd = zio->io_vd; int c; if (vd == NULL) { dva_t *dva = zio->io_bp->blk_dva; spa_t *spa = zio->io_spa; mm = vdev_mirror_map_alloc(BP_GET_NDVAS(zio->io_bp), B_FALSE, B_TRUE); 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 { mm = vdev_mirror_map_alloc(vd->vdev_children, (vd->vdev_ops == &vdev_replacing_ops || vd->vdev_ops == &vdev_spare_ops), 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) { 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; } /* * 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. */ static int vdev_mirror_dva_select(zio_t *zio, int p) { dva_t *dva = zio->io_bp->blk_dva; mirror_map_t *mm = zio->io_vsd; int preferred; int c; preferred = mm->mm_preferred[p]; for (p--; p >= 0; p--) { c = mm->mm_preferred[p]; if (DVA_GET_VDEV(&dva[c]) == DVA_GET_VDEV(&dva[preferred])) preferred = c; } return (preferred); } static int vdev_mirror_preferred_child_randomize(zio_t *zio) { mirror_map_t *mm = zio->io_vsd; int p; if (mm->mm_root) { p = spa_get_random(mm->mm_preferred_cnt); return (vdev_mirror_dva_select(zio, p)); } /* * To ensure we don't always favour the first matching vdev, * which could lead to wear leveling issues on SSD's, we * use the I/O offset as a pseudo random seed into the vdevs * which have the lowest load. */ p = (zio->io_offset >> vdev_mirror_shift) % mm->mm_preferred_cnt; return (mm->mm_preferred[p]); } /* * Try to find a vdev whose DTL doesn't contain the block we want to read * prefering vdevs based on determined load. * * 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; uint64_t txg = zio->io_txg; int c, lowest_load; ASSERT(zio->io_bp == NULL || BP_PHYSICAL_BIRTH(zio->io_bp) == txg); lowest_load = INT_MAX; mm->mm_preferred_cnt = 0; for (c = 0; c < mm->mm_children; c++) { mirror_child_t *mc; mc = &mm->mm_child[c]; if (mc->mc_tried || mc->mc_skipped) continue; if (mc->mc_vd == NULL || !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)) { mc->mc_error = SET_ERROR(ESTALE); mc->mc_skipped = 1; mc->mc_speculative = 1; continue; } mc->mc_load = vdev_mirror_load(mm, mc->mc_vd, mc->mc_offset); if (mc->mc_load > lowest_load) continue; if (mc->mc_load < lowest_load) { lowest_load = mc->mc_load; mm->mm_preferred_cnt = 0; } mm->mm_preferred[mm->mm_preferred_cnt] = c; mm->mm_preferred_cnt++; } if (mm->mm_preferred_cnt == 1) { MIRROR_BUMP(vdev_mirror_stat_preferred_found); return (mm->mm_preferred[0]); } if (mm->mm_preferred_cnt > 1) { MIRROR_BUMP(vdev_mirror_stat_preferred_not_found); return (vdev_mirror_preferred_child_randomize(zio)); } /* * 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_init(zio); if (zio->io_type == ZIO_TYPE_READ) { if (zio->io_bp != NULL && (zio->io_flags & ZIO_FLAG_SCRUB) && !mm->mm_replacing) { /* * 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; 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_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; /* * 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) 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, 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, 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, NULL, NULL, VDEV_TYPE_SPARE, /* name of this vdev type */ B_FALSE /* not a leaf vdev */ }; #if defined(_KERNEL) && defined(HAVE_SPL) /* BEGIN CSTYLED */ module_param(zfs_vdev_mirror_rotating_inc, int, 0644); MODULE_PARM_DESC(zfs_vdev_mirror_rotating_inc, "Rotating media load increment for non-seeking I/O's"); module_param(zfs_vdev_mirror_rotating_seek_inc, int, 0644); MODULE_PARM_DESC(zfs_vdev_mirror_rotating_seek_inc, "Rotating media load increment for seeking I/O's"); module_param(zfs_vdev_mirror_rotating_seek_offset, int, 0644); MODULE_PARM_DESC(zfs_vdev_mirror_rotating_seek_offset, "Offset in bytes from the last I/O which " "triggers a reduced rotating media seek increment"); module_param(zfs_vdev_mirror_non_rotating_inc, int, 0644); MODULE_PARM_DESC(zfs_vdev_mirror_non_rotating_inc, "Non-rotating media load increment for non-seeking I/O's"); module_param(zfs_vdev_mirror_non_rotating_seek_inc, int, 0644); MODULE_PARM_DESC(zfs_vdev_mirror_non_rotating_seek_inc, "Non-rotating media load increment for seeking I/O's"); /* END CSTYLED */ #endif