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Diffstat (limited to 'module/zfs/zio.c')
| -rw-r--r-- | module/zfs/zio.c | 2273 |
1 files changed, 2273 insertions, 0 deletions
diff --git a/module/zfs/zio.c b/module/zfs/zio.c new file mode 100644 index 000000000..d347920ea --- /dev/null +++ b/module/zfs/zio.c @@ -0,0 +1,2273 @@ +/* + * 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/fm/fs/zfs.h> +#include <sys/spa.h> +#include <sys/txg.h> +#include <sys/spa_impl.h> +#include <sys/vdev_impl.h> +#include <sys/zio_impl.h> +#include <sys/zio_compress.h> +#include <sys/zio_checksum.h> + +/* + * ========================================================================== + * I/O priority table + * ========================================================================== + */ +uint8_t zio_priority_table[ZIO_PRIORITY_TABLE_SIZE] = { + 0, /* ZIO_PRIORITY_NOW */ + 0, /* ZIO_PRIORITY_SYNC_READ */ + 0, /* ZIO_PRIORITY_SYNC_WRITE */ + 6, /* ZIO_PRIORITY_ASYNC_READ */ + 4, /* ZIO_PRIORITY_ASYNC_WRITE */ + 4, /* ZIO_PRIORITY_FREE */ + 0, /* ZIO_PRIORITY_CACHE_FILL */ + 0, /* ZIO_PRIORITY_LOG_WRITE */ + 10, /* ZIO_PRIORITY_RESILVER */ + 20, /* ZIO_PRIORITY_SCRUB */ +}; + +/* + * ========================================================================== + * I/O type descriptions + * ========================================================================== + */ +char *zio_type_name[ZIO_TYPES] = { + "null", "read", "write", "free", "claim", "ioctl" }; + +#define SYNC_PASS_DEFERRED_FREE 1 /* defer frees after this pass */ +#define SYNC_PASS_DONT_COMPRESS 4 /* don't compress after this pass */ +#define SYNC_PASS_REWRITE 1 /* rewrite new bps after this pass */ + +/* + * ========================================================================== + * I/O kmem caches + * ========================================================================== + */ +kmem_cache_t *zio_cache; +kmem_cache_t *zio_buf_cache[SPA_MAXBLOCKSIZE >> SPA_MINBLOCKSHIFT]; +kmem_cache_t *zio_data_buf_cache[SPA_MAXBLOCKSIZE >> SPA_MINBLOCKSHIFT]; + +#ifdef _KERNEL +extern vmem_t *zio_alloc_arena; +#endif + +/* + * An allocating zio is one that either currently has the DVA allocate + * stage set or will have it later in its lifetime. + */ +#define IO_IS_ALLOCATING(zio) \ + ((zio)->io_orig_pipeline & (1U << ZIO_STAGE_DVA_ALLOCATE)) + +void +zio_init(void) +{ + size_t c; + vmem_t *data_alloc_arena = NULL; + +#ifdef _KERNEL + data_alloc_arena = zio_alloc_arena; +#endif + zio_cache = kmem_cache_create("zio_cache", sizeof (zio_t), 0, + NULL, NULL, NULL, NULL, NULL, 0); + + /* + * For small buffers, we want a cache for each multiple of + * SPA_MINBLOCKSIZE. For medium-size buffers, we want a cache + * for each quarter-power of 2. For large buffers, we want + * a cache for each multiple of PAGESIZE. + */ + for (c = 0; c < SPA_MAXBLOCKSIZE >> SPA_MINBLOCKSHIFT; c++) { + size_t size = (c + 1) << SPA_MINBLOCKSHIFT; + size_t p2 = size; + size_t align = 0; + + while (p2 & (p2 - 1)) + p2 &= p2 - 1; + + if (size <= 4 * SPA_MINBLOCKSIZE) { + align = SPA_MINBLOCKSIZE; + } else if (P2PHASE(size, PAGESIZE) == 0) { + align = PAGESIZE; + } else if (P2PHASE(size, p2 >> 2) == 0) { + align = p2 >> 2; + } + + if (align != 0) { + char name[36]; + (void) sprintf(name, "zio_buf_%lu", (ulong_t)size); + zio_buf_cache[c] = kmem_cache_create(name, size, + align, NULL, NULL, NULL, NULL, NULL, KMC_NODEBUG); + + (void) sprintf(name, "zio_data_buf_%lu", (ulong_t)size); + zio_data_buf_cache[c] = kmem_cache_create(name, size, + align, NULL, NULL, NULL, NULL, data_alloc_arena, + KMC_NODEBUG); + } + } + + while (--c != 0) { + ASSERT(zio_buf_cache[c] != NULL); + if (zio_buf_cache[c - 1] == NULL) + zio_buf_cache[c - 1] = zio_buf_cache[c]; + + ASSERT(zio_data_buf_cache[c] != NULL); + if (zio_data_buf_cache[c - 1] == NULL) + zio_data_buf_cache[c - 1] = zio_data_buf_cache[c]; + } + + zio_inject_init(); +} + +void +zio_fini(void) +{ + size_t c; + kmem_cache_t *last_cache = NULL; + kmem_cache_t *last_data_cache = NULL; + + for (c = 0; c < SPA_MAXBLOCKSIZE >> SPA_MINBLOCKSHIFT; c++) { + if (zio_buf_cache[c] != last_cache) { + last_cache = zio_buf_cache[c]; + kmem_cache_destroy(zio_buf_cache[c]); + } + zio_buf_cache[c] = NULL; + + if (zio_data_buf_cache[c] != last_data_cache) { + last_data_cache = zio_data_buf_cache[c]; + kmem_cache_destroy(zio_data_buf_cache[c]); + } + zio_data_buf_cache[c] = NULL; + } + + kmem_cache_destroy(zio_cache); + + zio_inject_fini(); +} + +/* + * ========================================================================== + * Allocate and free I/O buffers + * ========================================================================== + */ + +/* + * Use zio_buf_alloc to allocate ZFS metadata. This data will appear in a + * crashdump if the kernel panics, so use it judiciously. Obviously, it's + * useful to inspect ZFS metadata, but if possible, we should avoid keeping + * excess / transient data in-core during a crashdump. + */ +void * +zio_buf_alloc(size_t size) +{ + size_t c = (size - 1) >> SPA_MINBLOCKSHIFT; + + ASSERT(c < SPA_MAXBLOCKSIZE >> SPA_MINBLOCKSHIFT); + + return (kmem_cache_alloc(zio_buf_cache[c], KM_PUSHPAGE)); +} + +/* + * Use zio_data_buf_alloc to allocate data. The data will not appear in a + * crashdump if the kernel panics. This exists so that we will limit the amount + * of ZFS data that shows up in a kernel crashdump. (Thus reducing the amount + * of kernel heap dumped to disk when the kernel panics) + */ +void * +zio_data_buf_alloc(size_t size) +{ + size_t c = (size - 1) >> SPA_MINBLOCKSHIFT; + + ASSERT(c < SPA_MAXBLOCKSIZE >> SPA_MINBLOCKSHIFT); + + return (kmem_cache_alloc(zio_data_buf_cache[c], KM_PUSHPAGE)); +} + +void +zio_buf_free(void *buf, size_t size) +{ + size_t c = (size - 1) >> SPA_MINBLOCKSHIFT; + + ASSERT(c < SPA_MAXBLOCKSIZE >> SPA_MINBLOCKSHIFT); + + kmem_cache_free(zio_buf_cache[c], buf); +} + +void +zio_data_buf_free(void *buf, size_t size) +{ + size_t c = (size - 1) >> SPA_MINBLOCKSHIFT; + + ASSERT(c < SPA_MAXBLOCKSIZE >> SPA_MINBLOCKSHIFT); + + kmem_cache_free(zio_data_buf_cache[c], buf); +} + +/* + * ========================================================================== + * Push and pop I/O transform buffers + * ========================================================================== + */ +static void +zio_push_transform(zio_t *zio, void *data, uint64_t size, uint64_t bufsize, + zio_transform_func_t *transform) +{ + zio_transform_t *zt = kmem_alloc(sizeof (zio_transform_t), KM_SLEEP); + + zt->zt_orig_data = zio->io_data; + zt->zt_orig_size = zio->io_size; + zt->zt_bufsize = bufsize; + zt->zt_transform = transform; + + zt->zt_next = zio->io_transform_stack; + zio->io_transform_stack = zt; + + zio->io_data = data; + zio->io_size = size; +} + +static void +zio_pop_transforms(zio_t *zio) +{ + zio_transform_t *zt; + + while ((zt = zio->io_transform_stack) != NULL) { + if (zt->zt_transform != NULL) + zt->zt_transform(zio, + zt->zt_orig_data, zt->zt_orig_size); + + zio_buf_free(zio->io_data, zt->zt_bufsize); + + zio->io_data = zt->zt_orig_data; + zio->io_size = zt->zt_orig_size; + zio->io_transform_stack = zt->zt_next; + + kmem_free(zt, sizeof (zio_transform_t)); + } +} + +/* + * ========================================================================== + * I/O transform callbacks for subblocks and decompression + * ========================================================================== + */ +static void +zio_subblock(zio_t *zio, void *data, uint64_t size) +{ + ASSERT(zio->io_size > size); + + if (zio->io_type == ZIO_TYPE_READ) + bcopy(zio->io_data, data, size); +} + +static void +zio_decompress(zio_t *zio, void *data, uint64_t size) +{ + if (zio->io_error == 0 && + zio_decompress_data(BP_GET_COMPRESS(zio->io_bp), + zio->io_data, zio->io_size, data, size) != 0) + zio->io_error = EIO; +} + +/* + * ========================================================================== + * I/O parent/child relationships and pipeline interlocks + * ========================================================================== + */ + +static void +zio_add_child(zio_t *pio, zio_t *zio) +{ + mutex_enter(&pio->io_lock); + if (zio->io_stage < ZIO_STAGE_READY) + pio->io_children[zio->io_child_type][ZIO_WAIT_READY]++; + if (zio->io_stage < ZIO_STAGE_DONE) + pio->io_children[zio->io_child_type][ZIO_WAIT_DONE]++; + zio->io_sibling_prev = NULL; + zio->io_sibling_next = pio->io_child; + if (pio->io_child != NULL) + pio->io_child->io_sibling_prev = zio; + pio->io_child = zio; + zio->io_parent = pio; + mutex_exit(&pio->io_lock); +} + +static void +zio_remove_child(zio_t *pio, zio_t *zio) +{ + zio_t *next, *prev; + + ASSERT(zio->io_parent == pio); + + mutex_enter(&pio->io_lock); + next = zio->io_sibling_next; + prev = zio->io_sibling_prev; + if (next != NULL) + next->io_sibling_prev = prev; + if (prev != NULL) + prev->io_sibling_next = next; + if (pio->io_child == zio) + pio->io_child = next; + mutex_exit(&pio->io_lock); +} + +static boolean_t +zio_wait_for_children(zio_t *zio, enum zio_child child, enum zio_wait_type wait) +{ + uint64_t *countp = &zio->io_children[child][wait]; + boolean_t waiting = B_FALSE; + + mutex_enter(&zio->io_lock); + ASSERT(zio->io_stall == NULL); + if (*countp != 0) { + zio->io_stage--; + zio->io_stall = countp; + waiting = B_TRUE; + } + mutex_exit(&zio->io_lock); + + return (waiting); +} + +static void +zio_notify_parent(zio_t *pio, zio_t *zio, enum zio_wait_type wait) +{ + uint64_t *countp = &pio->io_children[zio->io_child_type][wait]; + int *errorp = &pio->io_child_error[zio->io_child_type]; + + mutex_enter(&pio->io_lock); + if (zio->io_error && !(zio->io_flags & ZIO_FLAG_DONT_PROPAGATE)) + *errorp = zio_worst_error(*errorp, zio->io_error); + pio->io_reexecute |= zio->io_reexecute; + ASSERT3U(*countp, >, 0); + if (--*countp == 0 && pio->io_stall == countp) { + pio->io_stall = NULL; + mutex_exit(&pio->io_lock); + zio_execute(pio); + } else { + mutex_exit(&pio->io_lock); + } +} + +static void +zio_inherit_child_errors(zio_t *zio, enum zio_child c) +{ + if (zio->io_child_error[c] != 0 && zio->io_error == 0) + zio->io_error = zio->io_child_error[c]; +} + +/* + * ========================================================================== + * Create the various types of I/O (read, write, free, etc) + * ========================================================================== + */ +static zio_t * +zio_create(zio_t *pio, spa_t *spa, uint64_t txg, blkptr_t *bp, + void *data, uint64_t size, zio_done_func_t *done, void *private, + zio_type_t type, int priority, int flags, vdev_t *vd, uint64_t offset, + const zbookmark_t *zb, uint8_t stage, uint32_t pipeline) +{ + zio_t *zio; + + ASSERT3U(size, <=, SPA_MAXBLOCKSIZE); + ASSERT(P2PHASE(size, SPA_MINBLOCKSIZE) == 0); + ASSERT(P2PHASE(offset, SPA_MINBLOCKSIZE) == 0); + + ASSERT(!vd || spa_config_held(spa, SCL_STATE_ALL, RW_READER)); + ASSERT(!bp || !(flags & ZIO_FLAG_CONFIG_WRITER)); + ASSERT(vd || stage == ZIO_STAGE_OPEN); + + zio = kmem_cache_alloc(zio_cache, KM_SLEEP); + bzero(zio, sizeof (zio_t)); + + mutex_init(&zio->io_lock, NULL, MUTEX_DEFAULT, NULL); + cv_init(&zio->io_cv, NULL, CV_DEFAULT, NULL); + + if (vd != NULL) + zio->io_child_type = ZIO_CHILD_VDEV; + else if (flags & ZIO_FLAG_GANG_CHILD) + zio->io_child_type = ZIO_CHILD_GANG; + else + zio->io_child_type = ZIO_CHILD_LOGICAL; + + if (bp != NULL) { + zio->io_bp = bp; + zio->io_bp_copy = *bp; + zio->io_bp_orig = *bp; + if (type != ZIO_TYPE_WRITE) + zio->io_bp = &zio->io_bp_copy; /* so caller can free */ + if (zio->io_child_type == ZIO_CHILD_LOGICAL) { + if (BP_IS_GANG(bp)) + pipeline |= ZIO_GANG_STAGES; + zio->io_logical = zio; + } + } + + zio->io_spa = spa; + zio->io_txg = txg; + zio->io_data = data; + zio->io_size = size; + zio->io_done = done; + zio->io_private = private; + zio->io_type = type; + zio->io_priority = priority; + zio->io_vd = vd; + zio->io_offset = offset; + zio->io_orig_flags = zio->io_flags = flags; + zio->io_orig_stage = zio->io_stage = stage; + zio->io_orig_pipeline = zio->io_pipeline = pipeline; + + if (zb != NULL) + zio->io_bookmark = *zb; + + if (pio != NULL) { + /* + * Logical I/Os can have logical, gang, or vdev children. + * Gang I/Os can have gang or vdev children. + * Vdev I/Os can only have vdev children. + * The following ASSERT captures all of these constraints. + */ + ASSERT(zio->io_child_type <= pio->io_child_type); + if (zio->io_logical == NULL) + zio->io_logical = pio->io_logical; + zio_add_child(pio, zio); + } + + return (zio); +} + +static void +zio_destroy(zio_t *zio) +{ + spa_t *spa = zio->io_spa; + uint8_t async_root = zio->io_async_root; + + mutex_destroy(&zio->io_lock); + cv_destroy(&zio->io_cv); + kmem_cache_free(zio_cache, zio); + + if (async_root) { + mutex_enter(&spa->spa_async_root_lock); + if (--spa->spa_async_root_count == 0) + cv_broadcast(&spa->spa_async_root_cv); + mutex_exit(&spa->spa_async_root_lock); + } +} + +zio_t * +zio_null(zio_t *pio, spa_t *spa, zio_done_func_t *done, void *private, + int flags) +{ + zio_t *zio; + + zio = zio_create(pio, spa, 0, NULL, NULL, 0, done, private, + ZIO_TYPE_NULL, ZIO_PRIORITY_NOW, flags, NULL, 0, NULL, + ZIO_STAGE_OPEN, ZIO_INTERLOCK_PIPELINE); + + return (zio); +} + +zio_t * +zio_root(spa_t *spa, zio_done_func_t *done, void *private, int flags) +{ + return (zio_null(NULL, spa, done, private, flags)); +} + +zio_t * +zio_read(zio_t *pio, spa_t *spa, const blkptr_t *bp, + void *data, uint64_t size, zio_done_func_t *done, void *private, + int priority, int flags, const zbookmark_t *zb) +{ + zio_t *zio; + + zio = zio_create(pio, spa, bp->blk_birth, (blkptr_t *)bp, + data, size, done, private, + ZIO_TYPE_READ, priority, flags, NULL, 0, zb, + ZIO_STAGE_OPEN, ZIO_READ_PIPELINE); + + return (zio); +} + +void +zio_skip_write(zio_t *zio) +{ + ASSERT(zio->io_type == ZIO_TYPE_WRITE); + ASSERT(zio->io_stage == ZIO_STAGE_READY); + ASSERT(!BP_IS_GANG(zio->io_bp)); + + zio->io_pipeline &= ~ZIO_VDEV_IO_STAGES; +} + +zio_t * +zio_write(zio_t *pio, spa_t *spa, uint64_t txg, blkptr_t *bp, + void *data, uint64_t size, zio_prop_t *zp, + zio_done_func_t *ready, zio_done_func_t *done, void *private, + int priority, int flags, const zbookmark_t *zb) +{ + zio_t *zio; + + ASSERT(zp->zp_checksum >= ZIO_CHECKSUM_OFF && + zp->zp_checksum < ZIO_CHECKSUM_FUNCTIONS && + zp->zp_compress >= ZIO_COMPRESS_OFF && + zp->zp_compress < ZIO_COMPRESS_FUNCTIONS && + zp->zp_type < DMU_OT_NUMTYPES && + zp->zp_level < 32 && + zp->zp_ndvas > 0 && + zp->zp_ndvas <= spa_max_replication(spa)); + ASSERT(ready != NULL); + + zio = zio_create(pio, spa, txg, bp, data, size, done, private, + ZIO_TYPE_WRITE, priority, flags, NULL, 0, zb, + ZIO_STAGE_OPEN, ZIO_WRITE_PIPELINE); + + zio->io_ready = ready; + zio->io_prop = *zp; + + return (zio); +} + +zio_t * +zio_rewrite(zio_t *pio, spa_t *spa, uint64_t txg, blkptr_t *bp, void *data, + uint64_t size, zio_done_func_t *done, void *private, int priority, + int flags, zbookmark_t *zb) +{ + zio_t *zio; + + zio = zio_create(pio, spa, txg, bp, data, size, done, private, + ZIO_TYPE_WRITE, priority, flags, NULL, 0, zb, + ZIO_STAGE_OPEN, ZIO_REWRITE_PIPELINE); + + return (zio); +} + +zio_t * +zio_free(zio_t *pio, spa_t *spa, uint64_t txg, blkptr_t *bp, + zio_done_func_t *done, void *private, int flags) +{ + zio_t *zio; + + ASSERT(!BP_IS_HOLE(bp)); + + if (bp->blk_fill == BLK_FILL_ALREADY_FREED) + return (zio_null(pio, spa, NULL, NULL, flags)); + + if (txg == spa->spa_syncing_txg && + spa_sync_pass(spa) > SYNC_PASS_DEFERRED_FREE) { + bplist_enqueue_deferred(&spa->spa_sync_bplist, bp); + return (zio_null(pio, spa, NULL, NULL, flags)); + } + + zio = zio_create(pio, spa, txg, bp, NULL, BP_GET_PSIZE(bp), + done, private, ZIO_TYPE_FREE, ZIO_PRIORITY_FREE, flags, + NULL, 0, NULL, ZIO_STAGE_OPEN, ZIO_FREE_PIPELINE); + + return (zio); +} + +zio_t * +zio_claim(zio_t *pio, spa_t *spa, uint64_t txg, blkptr_t *bp, + zio_done_func_t *done, void *private, int flags) +{ + zio_t *zio; + + /* + * A claim is an allocation of a specific block. Claims are needed + * to support immediate writes in the intent log. The issue is that + * immediate writes contain committed data, but in a txg that was + * *not* committed. Upon opening the pool after an unclean shutdown, + * the intent log claims all blocks that contain immediate write data + * so that the SPA knows they're in use. + * + * All claims *must* be resolved in the first txg -- before the SPA + * starts allocating blocks -- so that nothing is allocated twice. + */ + ASSERT3U(spa->spa_uberblock.ub_rootbp.blk_birth, <, spa_first_txg(spa)); + ASSERT3U(spa_first_txg(spa), <=, txg); + + zio = zio_create(pio, spa, txg, bp, NULL, BP_GET_PSIZE(bp), + done, private, ZIO_TYPE_CLAIM, ZIO_PRIORITY_NOW, flags, + NULL, 0, NULL, ZIO_STAGE_OPEN, ZIO_CLAIM_PIPELINE); + + return (zio); +} + +zio_t * +zio_ioctl(zio_t *pio, spa_t *spa, vdev_t *vd, int cmd, + zio_done_func_t *done, void *private, int priority, int flags) +{ + zio_t *zio; + int c; + + if (vd->vdev_children == 0) { + zio = zio_create(pio, spa, 0, NULL, NULL, 0, done, private, + ZIO_TYPE_IOCTL, priority, flags, vd, 0, NULL, + ZIO_STAGE_OPEN, ZIO_IOCTL_PIPELINE); + + zio->io_cmd = cmd; + } else { + zio = zio_null(pio, spa, NULL, NULL, flags); + + for (c = 0; c < vd->vdev_children; c++) + zio_nowait(zio_ioctl(zio, spa, vd->vdev_child[c], cmd, + done, private, priority, flags)); + } + + return (zio); +} + +zio_t * +zio_read_phys(zio_t *pio, vdev_t *vd, uint64_t offset, uint64_t size, + void *data, int checksum, zio_done_func_t *done, void *private, + int priority, int flags, boolean_t labels) +{ + zio_t *zio; + + ASSERT(vd->vdev_children == 0); + ASSERT(!labels || offset + size <= VDEV_LABEL_START_SIZE || + offset >= vd->vdev_psize - VDEV_LABEL_END_SIZE); + ASSERT3U(offset + size, <=, vd->vdev_psize); + + zio = zio_create(pio, vd->vdev_spa, 0, NULL, data, size, done, private, + ZIO_TYPE_READ, priority, flags, vd, offset, NULL, + ZIO_STAGE_OPEN, ZIO_READ_PHYS_PIPELINE); + + zio->io_prop.zp_checksum = checksum; + + return (zio); +} + +zio_t * +zio_write_phys(zio_t *pio, vdev_t *vd, uint64_t offset, uint64_t size, + void *data, int checksum, zio_done_func_t *done, void *private, + int priority, int flags, boolean_t labels) +{ + zio_t *zio; + + ASSERT(vd->vdev_children == 0); + ASSERT(!labels || offset + size <= VDEV_LABEL_START_SIZE || + offset >= vd->vdev_psize - VDEV_LABEL_END_SIZE); + ASSERT3U(offset + size, <=, vd->vdev_psize); + + zio = zio_create(pio, vd->vdev_spa, 0, NULL, data, size, done, private, + ZIO_TYPE_WRITE, priority, flags, vd, offset, NULL, + ZIO_STAGE_OPEN, ZIO_WRITE_PHYS_PIPELINE); + + zio->io_prop.zp_checksum = checksum; + + if (zio_checksum_table[checksum].ci_zbt) { + /* + * zbt checksums are necessarily destructive -- they modify + * the end of the write buffer to hold the verifier/checksum. + * Therefore, we must make a local copy in case the data is + * being written to multiple places in parallel. + */ + void *wbuf = zio_buf_alloc(size); + bcopy(data, wbuf, size); + zio_push_transform(zio, wbuf, size, size, NULL); + } + + return (zio); +} + +/* + * Create a child I/O to do some work for us. + */ +zio_t * +zio_vdev_child_io(zio_t *pio, blkptr_t *bp, vdev_t *vd, uint64_t offset, + void *data, uint64_t size, int type, int priority, int flags, + zio_done_func_t *done, void *private) +{ + uint32_t pipeline = ZIO_VDEV_CHILD_PIPELINE; + zio_t *zio; + + ASSERT(vd->vdev_parent == + (pio->io_vd ? pio->io_vd : pio->io_spa->spa_root_vdev)); + + if (type == ZIO_TYPE_READ && bp != NULL) { + /* + * If we have the bp, then the child should perform the + * checksum and the parent need not. This pushes error + * detection as close to the leaves as possible and + * eliminates redundant checksums in the interior nodes. + */ + pipeline |= 1U << ZIO_STAGE_CHECKSUM_VERIFY; + pio->io_pipeline &= ~(1U << ZIO_STAGE_CHECKSUM_VERIFY); + } + + if (vd->vdev_children == 0) + offset += VDEV_LABEL_START_SIZE; + + zio = zio_create(pio, pio->io_spa, pio->io_txg, bp, data, size, + done, private, type, priority, + (pio->io_flags & ZIO_FLAG_VDEV_INHERIT) | + ZIO_FLAG_CANFAIL | ZIO_FLAG_DONT_PROPAGATE | flags, + vd, offset, &pio->io_bookmark, + ZIO_STAGE_VDEV_IO_START - 1, pipeline); + + return (zio); +} + +zio_t * +zio_vdev_delegated_io(vdev_t *vd, uint64_t offset, void *data, uint64_t size, + int type, int priority, int flags, zio_done_func_t *done, void *private) +{ + zio_t *zio; + + ASSERT(vd->vdev_ops->vdev_op_leaf); + + zio = zio_create(NULL, vd->vdev_spa, 0, NULL, + data, size, done, private, type, priority, + flags | ZIO_FLAG_CANFAIL | ZIO_FLAG_DONT_RETRY, + vd, offset, NULL, + ZIO_STAGE_VDEV_IO_START - 1, ZIO_VDEV_CHILD_PIPELINE); + + return (zio); +} + +void +zio_flush(zio_t *zio, vdev_t *vd) +{ + zio_nowait(zio_ioctl(zio, zio->io_spa, vd, DKIOCFLUSHWRITECACHE, + NULL, NULL, ZIO_PRIORITY_NOW, + ZIO_FLAG_CANFAIL | ZIO_FLAG_DONT_PROPAGATE | ZIO_FLAG_DONT_RETRY)); +} + +/* + * ========================================================================== + * Prepare to read and write logical blocks + * ========================================================================== + */ + +static int +zio_read_bp_init(zio_t *zio) +{ + blkptr_t *bp = zio->io_bp; + + if (BP_GET_COMPRESS(bp) != ZIO_COMPRESS_OFF && zio->io_logical == zio) { + uint64_t csize = BP_GET_PSIZE(bp); + void *cbuf = zio_buf_alloc(csize); + + zio_push_transform(zio, cbuf, csize, csize, zio_decompress); + } + + if (!dmu_ot[BP_GET_TYPE(bp)].ot_metadata && BP_GET_LEVEL(bp) == 0) + zio->io_flags |= ZIO_FLAG_DONT_CACHE; + + return (ZIO_PIPELINE_CONTINUE); +} + +static int +zio_write_bp_init(zio_t *zio) +{ + zio_prop_t *zp = &zio->io_prop; + int compress = zp->zp_compress; + blkptr_t *bp = zio->io_bp; + void *cbuf; + uint64_t lsize = zio->io_size; + uint64_t csize = lsize; + uint64_t cbufsize = 0; + int pass = 1; + + /* + * If our children haven't all reached the ready stage, + * wait for them and then repeat this pipeline stage. + */ + if (zio_wait_for_children(zio, ZIO_CHILD_GANG, ZIO_WAIT_READY) || + zio_wait_for_children(zio, ZIO_CHILD_LOGICAL, ZIO_WAIT_READY)) + return (ZIO_PIPELINE_STOP); + + if (!IO_IS_ALLOCATING(zio)) + return (ZIO_PIPELINE_CONTINUE); + + ASSERT(compress != ZIO_COMPRESS_INHERIT); + + if (bp->blk_birth == zio->io_txg) { + /* + * We're rewriting an existing block, which means we're + * working on behalf of spa_sync(). For spa_sync() to + * converge, it must eventually be the case that we don't + * have to allocate new blocks. But compression changes + * the blocksize, which forces a reallocate, and makes + * convergence take longer. Therefore, after the first + * few passes, stop compressing to ensure convergence. + */ + pass = spa_sync_pass(zio->io_spa); + ASSERT(pass > 1); + + if (pass > SYNC_PASS_DONT_COMPRESS) + compress = ZIO_COMPRESS_OFF; + + /* + * Only MOS (objset 0) data should need to be rewritten. + */ + ASSERT(zio->io_logical->io_bookmark.zb_objset == 0); + + /* Make sure someone doesn't change their mind on overwrites */ + ASSERT(MIN(zp->zp_ndvas + BP_IS_GANG(bp), + spa_max_replication(zio->io_spa)) == BP_GET_NDVAS(bp)); + } + + if (compress != ZIO_COMPRESS_OFF) { + if (!zio_compress_data(compress, zio->io_data, zio->io_size, + &cbuf, &csize, &cbufsize)) { + compress = ZIO_COMPRESS_OFF; + } else if (csize != 0) { + zio_push_transform(zio, cbuf, csize, cbufsize, NULL); + } + } + + /* + * The final pass of spa_sync() must be all rewrites, but the first + * few passes offer a trade-off: allocating blocks defers convergence, + * but newly allocated blocks are sequential, so they can be written + * to disk faster. Therefore, we allow the first few passes of + * spa_sync() to allocate new blocks, but force rewrites after that. + * There should only be a handful of blocks after pass 1 in any case. + */ + if (bp->blk_birth == zio->io_txg && BP_GET_PSIZE(bp) == csize && + pass > SYNC_PASS_REWRITE) { + ASSERT(csize != 0); + uint32_t gang_stages = zio->io_pipeline & ZIO_GANG_STAGES; + zio->io_pipeline = ZIO_REWRITE_PIPELINE | gang_stages; + zio->io_flags |= ZIO_FLAG_IO_REWRITE; + } else { + BP_ZERO(bp); + zio->io_pipeline = ZIO_WRITE_PIPELINE; + } + + if (csize == 0) { + zio->io_pipeline = ZIO_INTERLOCK_PIPELINE; + } else { + ASSERT(zp->zp_checksum != ZIO_CHECKSUM_GANG_HEADER); + BP_SET_LSIZE(bp, lsize); + BP_SET_PSIZE(bp, csize); + BP_SET_COMPRESS(bp, compress); + BP_SET_CHECKSUM(bp, zp->zp_checksum); + BP_SET_TYPE(bp, zp->zp_type); + BP_SET_LEVEL(bp, zp->zp_level); + BP_SET_BYTEORDER(bp, ZFS_HOST_BYTEORDER); + } + + return (ZIO_PIPELINE_CONTINUE); +} + +/* + * ========================================================================== + * Execute the I/O pipeline + * ========================================================================== + */ + +static void +zio_taskq_dispatch(zio_t *zio, enum zio_taskq_type q) +{ + zio_type_t t = zio->io_type; + + /* + * If we're a config writer, the normal issue and interrupt threads + * may all be blocked waiting for the config lock. In this case, + * select the otherwise-unused taskq for ZIO_TYPE_NULL. + */ + if (zio->io_flags & ZIO_FLAG_CONFIG_WRITER) + t = ZIO_TYPE_NULL; + + /* + * A similar issue exists for the L2ARC write thread until L2ARC 2.0. + */ + if (t == ZIO_TYPE_WRITE && zio->io_vd && zio->io_vd->vdev_aux) + t = ZIO_TYPE_NULL; + + (void) taskq_dispatch(zio->io_spa->spa_zio_taskq[t][q], + (task_func_t *)zio_execute, zio, TQ_SLEEP); +} + +static boolean_t +zio_taskq_member(zio_t *zio, enum zio_taskq_type q) +{ + kthread_t *executor = zio->io_executor; + spa_t *spa = zio->io_spa; + + for (zio_type_t t = 0; t < ZIO_TYPES; t++) + if (taskq_member(spa->spa_zio_taskq[t][q], executor)) + return (B_TRUE); + + return (B_FALSE); +} + +static int +zio_issue_async(zio_t *zio) +{ + zio_taskq_dispatch(zio, ZIO_TASKQ_ISSUE); + + return (ZIO_PIPELINE_STOP); +} + +void +zio_interrupt(zio_t *zio) +{ + zio_taskq_dispatch(zio, ZIO_TASKQ_INTERRUPT); +} + +/* + * Execute the I/O pipeline until one of the following occurs: + * (1) the I/O completes; (2) the pipeline stalls waiting for + * dependent child I/Os; (3) the I/O issues, so we're waiting + * for an I/O completion interrupt; (4) the I/O is delegated by + * vdev-level caching or aggregation; (5) the I/O is deferred + * due to vdev-level queueing; (6) the I/O is handed off to + * another thread. In all cases, the pipeline stops whenever + * there's no CPU work; it never burns a thread in cv_wait(). + * + * There's no locking on io_stage because there's no legitimate way + * for multiple threads to be attempting to process the same I/O. + */ +static zio_pipe_stage_t *zio_pipeline[ZIO_STAGES]; + +void +zio_execute(zio_t *zio) +{ + zio->io_executor = curthread; + + while (zio->io_stage < ZIO_STAGE_DONE) { + uint32_t pipeline = zio->io_pipeline; + zio_stage_t stage = zio->io_stage; + int rv; + + ASSERT(!MUTEX_HELD(&zio->io_lock)); + + while (((1U << ++stage) & pipeline) == 0) + continue; + + ASSERT(stage <= ZIO_STAGE_DONE); + ASSERT(zio->io_stall == NULL); + + /* + * If we are in interrupt context and this pipeline stage + * will grab a config lock that is held across I/O, + * issue async to avoid deadlock. + */ + if (((1U << stage) & ZIO_CONFIG_LOCK_BLOCKING_STAGES) && + zio->io_vd == NULL && + zio_taskq_member(zio, ZIO_TASKQ_INTERRUPT)) { + zio_taskq_dispatch(zio, ZIO_TASKQ_ISSUE); + return; + } + + zio->io_stage = stage; + rv = zio_pipeline[stage](zio); + + if (rv == ZIO_PIPELINE_STOP) + return; + + ASSERT(rv == ZIO_PIPELINE_CONTINUE); + } +} + +/* + * ========================================================================== + * Initiate I/O, either sync or async + * ========================================================================== + */ +int +zio_wait(zio_t *zio) +{ + int error; + + ASSERT(zio->io_stage == ZIO_STAGE_OPEN); + ASSERT(zio->io_executor == NULL); + + zio->io_waiter = curthread; + + zio_execute(zio); + + mutex_enter(&zio->io_lock); + while (zio->io_executor != NULL) + cv_wait(&zio->io_cv, &zio->io_lock); + mutex_exit(&zio->io_lock); + + error = zio->io_error; + zio_destroy(zio); + + return (error); +} + +void +zio_nowait(zio_t *zio) +{ + ASSERT(zio->io_executor == NULL); + + if (zio->io_parent == NULL && zio->io_child_type == ZIO_CHILD_LOGICAL) { + /* + * This is a logical async I/O with no parent to wait for it. + * Attach it to the pool's global async root zio so that + * spa_unload() has a way of waiting for async I/O to finish. + */ + spa_t *spa = zio->io_spa; + zio->io_async_root = B_TRUE; + mutex_enter(&spa->spa_async_root_lock); + spa->spa_async_root_count++; + mutex_exit(&spa->spa_async_root_lock); + } + + zio_execute(zio); +} + +/* + * ========================================================================== + * Reexecute or suspend/resume failed I/O + * ========================================================================== + */ + +static void +zio_reexecute(zio_t *pio) +{ + zio_t *zio, *zio_next; + + pio->io_flags = pio->io_orig_flags; + pio->io_stage = pio->io_orig_stage; + pio->io_pipeline = pio->io_orig_pipeline; + pio->io_reexecute = 0; + pio->io_error = 0; + for (int c = 0; c < ZIO_CHILD_TYPES; c++) + pio->io_child_error[c] = 0; + + if (IO_IS_ALLOCATING(pio)) { + /* + * Remember the failed bp so that the io_ready() callback + * can update its accounting upon reexecution. The block + * was already freed in zio_done(); we indicate this with + * a fill count of -1 so that zio_free() knows to skip it. + */ + blkptr_t *bp = pio->io_bp; + ASSERT(bp->blk_birth == 0 || bp->blk_birth == pio->io_txg); + bp->blk_fill = BLK_FILL_ALREADY_FREED; + pio->io_bp_orig = *bp; + BP_ZERO(bp); + } + + /* + * As we reexecute pio's children, new children could be created. + * New children go to the head of the io_child list, however, + * so we will (correctly) not reexecute them. The key is that + * the remainder of the io_child list, from 'zio_next' onward, + * cannot be affected by any side effects of reexecuting 'zio'. + */ + for (zio = pio->io_child; zio != NULL; zio = zio_next) { + zio_next = zio->io_sibling_next; + mutex_enter(&pio->io_lock); + pio->io_children[zio->io_child_type][ZIO_WAIT_READY]++; + pio->io_children[zio->io_child_type][ZIO_WAIT_DONE]++; + mutex_exit(&pio->io_lock); + zio_reexecute(zio); + } + + /* + * Now that all children have been reexecuted, execute the parent. + */ + zio_execute(pio); +} + +void +zio_suspend(spa_t *spa, zio_t *zio) +{ + if (spa_get_failmode(spa) == ZIO_FAILURE_MODE_PANIC) + fm_panic("Pool '%s' has encountered an uncorrectable I/O " + "failure and the failure mode property for this pool " + "is set to panic.", spa_name(spa)); + + zfs_ereport_post(FM_EREPORT_ZFS_IO_FAILURE, spa, NULL, NULL, 0, 0); + + mutex_enter(&spa->spa_suspend_lock); + + if (spa->spa_suspend_zio_root == NULL) + spa->spa_suspend_zio_root = zio_root(spa, NULL, NULL, 0); + + spa->spa_suspended = B_TRUE; + + if (zio != NULL) { + ASSERT(zio != spa->spa_suspend_zio_root); + ASSERT(zio->io_child_type == ZIO_CHILD_LOGICAL); + ASSERT(zio->io_parent == NULL); + ASSERT(zio->io_stage == ZIO_STAGE_DONE); + zio_add_child(spa->spa_suspend_zio_root, zio); + } + + mutex_exit(&spa->spa_suspend_lock); +} + +void +zio_resume(spa_t *spa) +{ + zio_t *pio, *zio; + + /* + * Reexecute all previously suspended i/o. + */ + mutex_enter(&spa->spa_suspend_lock); + spa->spa_suspended = B_FALSE; + cv_broadcast(&spa->spa_suspend_cv); + pio = spa->spa_suspend_zio_root; + spa->spa_suspend_zio_root = NULL; + mutex_exit(&spa->spa_suspend_lock); + + if (pio == NULL) + return; + + while ((zio = pio->io_child) != NULL) { + zio_remove_child(pio, zio); + zio->io_parent = NULL; + zio_reexecute(zio); + } + + ASSERT(pio->io_children[ZIO_CHILD_LOGICAL][ZIO_WAIT_DONE] == 0); + + (void) zio_wait(pio); +} + +void +zio_resume_wait(spa_t *spa) +{ + mutex_enter(&spa->spa_suspend_lock); + while (spa_suspended(spa)) + cv_wait(&spa->spa_suspend_cv, &spa->spa_suspend_lock); + mutex_exit(&spa->spa_suspend_lock); +} + +/* + * ========================================================================== + * Gang blocks. + * + * A gang block is a collection of small blocks that looks to the DMU + * like one large block. When zio_dva_allocate() cannot find a block + * of the requested size, due to either severe fragmentation or the pool + * being nearly full, it calls zio_write_gang_block() to construct the + * block from smaller fragments. + * + * A gang block consists of a gang header (zio_gbh_phys_t) and up to + * three (SPA_GBH_NBLKPTRS) gang members. The gang header is just like + * an indirect block: it's an array of block pointers. It consumes + * only one sector and hence is allocatable regardless of fragmentation. + * The gang header's bps point to its gang members, which hold the data. + * + * Gang blocks are self-checksumming, using the bp's <vdev, offset, txg> + * as the verifier to ensure uniqueness of the SHA256 checksum. + * Critically, the gang block bp's blk_cksum is the checksum of the data, + * not the gang header. This ensures that data block signatures (needed for + * deduplication) are independent of how the block is physically stored. + * + * Gang blocks can be nested: a gang member may itself be a gang block. + * Thus every gang block is a tree in which root and all interior nodes are + * gang headers, and the leaves are normal blocks that contain user data. + * The root of the gang tree is called the gang leader. + * + * To perform any operation (read, rewrite, free, claim) on a gang block, + * zio_gang_assemble() first assembles the gang tree (minus data leaves) + * in the io_gang_tree field of the original logical i/o by recursively + * reading the gang leader and all gang headers below it. This yields + * an in-core tree containing the contents of every gang header and the + * bps for every constituent of the gang block. + * + * With the gang tree now assembled, zio_gang_issue() just walks the gang tree + * and invokes a callback on each bp. To free a gang block, zio_gang_issue() + * calls zio_free_gang() -- a trivial wrapper around zio_free() -- for each bp. + * zio_claim_gang() provides a similarly trivial wrapper for zio_claim(). + * zio_read_gang() is a wrapper around zio_read() that omits reading gang + * headers, since we already have those in io_gang_tree. zio_rewrite_gang() + * performs a zio_rewrite() of the data or, for gang headers, a zio_rewrite() + * of the gang header plus zio_checksum_compute() of the data to update the + * gang header's blk_cksum as described above. + * + * The two-phase assemble/issue model solves the problem of partial failure -- + * what if you'd freed part of a gang block but then couldn't read the + * gang header for another part? Assembling the entire gang tree first + * ensures that all the necessary gang header I/O has succeeded before + * starting the actual work of free, claim, or write. Once the gang tree + * is assembled, free and claim are in-memory operations that cannot fail. + * + * In the event that a gang write fails, zio_dva_unallocate() walks the + * gang tree to immediately free (i.e. insert back into the space map) + * everything we've allocated. This ensures that we don't get ENOSPC + * errors during repeated suspend/resume cycles due to a flaky device. + * + * Gang rewrites only happen during sync-to-convergence. If we can't assemble + * the gang tree, we won't modify the block, so we can safely defer the free + * (knowing that the block is still intact). If we *can* assemble the gang + * tree, then even if some of the rewrites fail, zio_dva_unallocate() will free + * each constituent bp and we can allocate a new block on the next sync pass. + * + * In all cases, the gang tree allows complete recovery from partial failure. + * ========================================================================== + */ + +static zio_t * +zio_read_gang(zio_t *pio, blkptr_t *bp, zio_gang_node_t *gn, void *data) +{ + if (gn != NULL) + return (pio); + + return (zio_read(pio, pio->io_spa, bp, data, BP_GET_PSIZE(bp), + NULL, NULL, pio->io_priority, ZIO_GANG_CHILD_FLAGS(pio), + &pio->io_bookmark)); +} + +zio_t * +zio_rewrite_gang(zio_t *pio, blkptr_t *bp, zio_gang_node_t *gn, void *data) +{ + zio_t *zio; + + if (gn != NULL) { + zio = zio_rewrite(pio, pio->io_spa, pio->io_txg, bp, + gn->gn_gbh, SPA_GANGBLOCKSIZE, NULL, NULL, pio->io_priority, + ZIO_GANG_CHILD_FLAGS(pio), &pio->io_bookmark); + /* + * As we rewrite each gang header, the pipeline will compute + * a new gang block header checksum for it; but no one will + * compute a new data checksum, so we do that here. The one + * exception is the gang leader: the pipeline already computed + * its data checksum because that stage precedes gang assembly. + * (Presently, nothing actually uses interior data checksums; + * this is just good hygiene.) + */ + if (gn != pio->io_logical->io_gang_tree) { + zio_checksum_compute(zio, BP_GET_CHECKSUM(bp), + data, BP_GET_PSIZE(bp)); + } + } else { + zio = zio_rewrite(pio, pio->io_spa, pio->io_txg, bp, + data, BP_GET_PSIZE(bp), NULL, NULL, pio->io_priority, + ZIO_GANG_CHILD_FLAGS(pio), &pio->io_bookmark); + } + + return (zio); +} + +/* ARGSUSED */ +zio_t * +zio_free_gang(zio_t *pio, blkptr_t *bp, zio_gang_node_t *gn, void *data) +{ + return (zio_free(pio, pio->io_spa, pio->io_txg, bp, + NULL, NULL, ZIO_GANG_CHILD_FLAGS(pio))); +} + +/* ARGSUSED */ +zio_t * +zio_claim_gang(zio_t *pio, blkptr_t *bp, zio_gang_node_t *gn, void *data) +{ + return (zio_claim(pio, pio->io_spa, pio->io_txg, bp, + NULL, NULL, ZIO_GANG_CHILD_FLAGS(pio))); +} + +static zio_gang_issue_func_t *zio_gang_issue_func[ZIO_TYPES] = { + NULL, + zio_read_gang, + zio_rewrite_gang, + zio_free_gang, + zio_claim_gang, + NULL +}; + +static void zio_gang_tree_assemble_done(zio_t *zio); + +static zio_gang_node_t * +zio_gang_node_alloc(zio_gang_node_t **gnpp) +{ + zio_gang_node_t *gn; + + ASSERT(*gnpp == NULL); + + gn = kmem_zalloc(sizeof (*gn), KM_SLEEP); + gn->gn_gbh = zio_buf_alloc(SPA_GANGBLOCKSIZE); + *gnpp = gn; + + return (gn); +} + +static void +zio_gang_node_free(zio_gang_node_t **gnpp) +{ + zio_gang_node_t *gn = *gnpp; + + for (int g = 0; g < SPA_GBH_NBLKPTRS; g++) + ASSERT(gn->gn_child[g] == NULL); + + zio_buf_free(gn->gn_gbh, SPA_GANGBLOCKSIZE); + kmem_free(gn, sizeof (*gn)); + *gnpp = NULL; +} + +static void +zio_gang_tree_free(zio_gang_node_t **gnpp) +{ + zio_gang_node_t *gn = *gnpp; + + if (gn == NULL) + return; + + for (int g = 0; g < SPA_GBH_NBLKPTRS; g++) + zio_gang_tree_free(&gn->gn_child[g]); + + zio_gang_node_free(gnpp); +} + +static void +zio_gang_tree_assemble(zio_t *lio, blkptr_t *bp, zio_gang_node_t **gnpp) +{ + zio_gang_node_t *gn = zio_gang_node_alloc(gnpp); + + ASSERT(lio->io_logical == lio); + ASSERT(BP_IS_GANG(bp)); + + zio_nowait(zio_read(lio, lio->io_spa, bp, gn->gn_gbh, + SPA_GANGBLOCKSIZE, zio_gang_tree_assemble_done, gn, + lio->io_priority, ZIO_GANG_CHILD_FLAGS(lio), &lio->io_bookmark)); +} + +static void +zio_gang_tree_assemble_done(zio_t *zio) +{ + zio_t *lio = zio->io_logical; + zio_gang_node_t *gn = zio->io_private; + blkptr_t *bp = zio->io_bp; + + ASSERT(zio->io_parent == lio); + ASSERT(zio->io_child == NULL); + + if (zio->io_error) + return; + + if (BP_SHOULD_BYTESWAP(bp)) + byteswap_uint64_array(zio->io_data, zio->io_size); + + ASSERT(zio->io_data == gn->gn_gbh); + ASSERT(zio->io_size == SPA_GANGBLOCKSIZE); + ASSERT(gn->gn_gbh->zg_tail.zbt_magic == ZBT_MAGIC); + + for (int g = 0; g < SPA_GBH_NBLKPTRS; g++) { + blkptr_t *gbp = &gn->gn_gbh->zg_blkptr[g]; + if (!BP_IS_GANG(gbp)) + continue; + zio_gang_tree_assemble(lio, gbp, &gn->gn_child[g]); + } +} + +static void +zio_gang_tree_issue(zio_t *pio, zio_gang_node_t *gn, blkptr_t *bp, void *data) +{ + zio_t *lio = pio->io_logical; + zio_t *zio; + + ASSERT(BP_IS_GANG(bp) == !!gn); + ASSERT(BP_GET_CHECKSUM(bp) == BP_GET_CHECKSUM(lio->io_bp)); + ASSERT(BP_GET_LSIZE(bp) == BP_GET_PSIZE(bp) || gn == lio->io_gang_tree); + + /* + * If you're a gang header, your data is in gn->gn_gbh. + * If you're a gang member, your data is in 'data' and gn == NULL. + */ + zio = zio_gang_issue_func[lio->io_type](pio, bp, gn, data); + + if (gn != NULL) { + ASSERT(gn->gn_gbh->zg_tail.zbt_magic == ZBT_MAGIC); + + for (int g = 0; g < SPA_GBH_NBLKPTRS; g++) { + blkptr_t *gbp = &gn->gn_gbh->zg_blkptr[g]; + if (BP_IS_HOLE(gbp)) + continue; + zio_gang_tree_issue(zio, gn->gn_child[g], gbp, data); + data = (char *)data + BP_GET_PSIZE(gbp); + } + } + + if (gn == lio->io_gang_tree) + ASSERT3P((char *)lio->io_data + lio->io_size, ==, data); + + if (zio != pio) + zio_nowait(zio); +} + +static int +zio_gang_assemble(zio_t *zio) +{ + blkptr_t *bp = zio->io_bp; + + ASSERT(BP_IS_GANG(bp) && zio == zio->io_logical); + + zio_gang_tree_assemble(zio, bp, &zio->io_gang_tree); + + return (ZIO_PIPELINE_CONTINUE); +} + +static int +zio_gang_issue(zio_t *zio) +{ + zio_t *lio = zio->io_logical; + blkptr_t *bp = zio->io_bp; + + if (zio_wait_for_children(zio, ZIO_CHILD_GANG, ZIO_WAIT_DONE)) + return (ZIO_PIPELINE_STOP); + + ASSERT(BP_IS_GANG(bp) && zio == lio); + + if (zio->io_child_error[ZIO_CHILD_GANG] == 0) + zio_gang_tree_issue(lio, lio->io_gang_tree, bp, lio->io_data); + else + zio_gang_tree_free(&lio->io_gang_tree); + + zio->io_pipeline = ZIO_INTERLOCK_PIPELINE; + + return (ZIO_PIPELINE_CONTINUE); +} + +static void +zio_write_gang_member_ready(zio_t *zio) +{ + zio_t *pio = zio->io_parent; + zio_t *lio = zio->io_logical; + dva_t *cdva = zio->io_bp->blk_dva; + dva_t *pdva = pio->io_bp->blk_dva; + uint64_t asize; + + if (BP_IS_HOLE(zio->io_bp)) + return; + + ASSERT(BP_IS_HOLE(&zio->io_bp_orig)); + + ASSERT(zio->io_child_type == ZIO_CHILD_GANG); + ASSERT3U(zio->io_prop.zp_ndvas, ==, lio->io_prop.zp_ndvas); + ASSERT3U(zio->io_prop.zp_ndvas, <=, BP_GET_NDVAS(zio->io_bp)); + ASSERT3U(pio->io_prop.zp_ndvas, <=, BP_GET_NDVAS(pio->io_bp)); + ASSERT3U(BP_GET_NDVAS(zio->io_bp), <=, BP_GET_NDVAS(pio->io_bp)); + + mutex_enter(&pio->io_lock); + for (int d = 0; d < BP_GET_NDVAS(zio->io_bp); d++) { + ASSERT(DVA_GET_GANG(&pdva[d])); + asize = DVA_GET_ASIZE(&pdva[d]); + asize += DVA_GET_ASIZE(&cdva[d]); + DVA_SET_ASIZE(&pdva[d], asize); + } + mutex_exit(&pio->io_lock); +} + +static int +zio_write_gang_block(zio_t *pio) +{ + spa_t *spa = pio->io_spa; + blkptr_t *bp = pio->io_bp; + zio_t *lio = pio->io_logical; + zio_t *zio; + zio_gang_node_t *gn, **gnpp; + zio_gbh_phys_t *gbh; + uint64_t txg = pio->io_txg; + uint64_t resid = pio->io_size; + uint64_t lsize; + int ndvas = lio->io_prop.zp_ndvas; + int gbh_ndvas = MIN(ndvas + 1, spa_max_replication(spa)); + zio_prop_t zp; + int error; + + error = metaslab_alloc(spa, spa->spa_normal_class, SPA_GANGBLOCKSIZE, + bp, gbh_ndvas, txg, pio == lio ? NULL : lio->io_bp, + METASLAB_HINTBP_FAVOR | METASLAB_GANG_HEADER); + if (error) { + pio->io_error = error; + return (ZIO_PIPELINE_CONTINUE); + } + + if (pio == lio) { + gnpp = &lio->io_gang_tree; + } else { + gnpp = pio->io_private; + ASSERT(pio->io_ready == zio_write_gang_member_ready); + } + + gn = zio_gang_node_alloc(gnpp); + gbh = gn->gn_gbh; + bzero(gbh, SPA_GANGBLOCKSIZE); + + /* + * Create the gang header. + */ + zio = zio_rewrite(pio, spa, txg, bp, gbh, SPA_GANGBLOCKSIZE, NULL, NULL, + pio->io_priority, ZIO_GANG_CHILD_FLAGS(pio), &pio->io_bookmark); + + /* + * Create and nowait the gang children. + */ + for (int g = 0; resid != 0; resid -= lsize, g++) { + lsize = P2ROUNDUP(resid / (SPA_GBH_NBLKPTRS - g), + SPA_MINBLOCKSIZE); + ASSERT(lsize >= SPA_MINBLOCKSIZE && lsize <= resid); + + zp.zp_checksum = lio->io_prop.zp_checksum; + zp.zp_compress = ZIO_COMPRESS_OFF; + zp.zp_type = DMU_OT_NONE; + zp.zp_level = 0; + zp.zp_ndvas = lio->io_prop.zp_ndvas; + + zio_nowait(zio_write(zio, spa, txg, &gbh->zg_blkptr[g], + (char *)pio->io_data + (pio->io_size - resid), lsize, &zp, + zio_write_gang_member_ready, NULL, &gn->gn_child[g], + pio->io_priority, ZIO_GANG_CHILD_FLAGS(pio), + &pio->io_bookmark)); + } + + /* + * Set pio's pipeline to just wait for zio to finish. + */ + pio->io_pipeline = ZIO_INTERLOCK_PIPELINE; + + zio_nowait(zio); + + return (ZIO_PIPELINE_CONTINUE); +} + +/* + * ========================================================================== + * Allocate and free blocks + * ========================================================================== + */ + +static int +zio_dva_allocate(zio_t *zio) +{ + spa_t *spa = zio->io_spa; + metaslab_class_t *mc = spa->spa_normal_class; + blkptr_t *bp = zio->io_bp; + int error; + + ASSERT(BP_IS_HOLE(bp)); + ASSERT3U(BP_GET_NDVAS(bp), ==, 0); + ASSERT3U(zio->io_prop.zp_ndvas, >, 0); + ASSERT3U(zio->io_prop.zp_ndvas, <=, spa_max_replication(spa)); + ASSERT3U(zio->io_size, ==, BP_GET_PSIZE(bp)); + + error = metaslab_alloc(spa, mc, zio->io_size, bp, + zio->io_prop.zp_ndvas, zio->io_txg, NULL, 0); + + if (error) { + if (error == ENOSPC && zio->io_size > SPA_MINBLOCKSIZE) + return (zio_write_gang_block(zio)); + zio->io_error = error; + } + + return (ZIO_PIPELINE_CONTINUE); +} + +static int +zio_dva_free(zio_t *zio) +{ + metaslab_free(zio->io_spa, zio->io_bp, zio->io_txg, B_FALSE); + + return (ZIO_PIPELINE_CONTINUE); +} + +static int +zio_dva_claim(zio_t *zio) +{ + int error; + + error = metaslab_claim(zio->io_spa, zio->io_bp, zio->io_txg); + if (error) + zio->io_error = error; + + return (ZIO_PIPELINE_CONTINUE); +} + +/* + * Undo an allocation. This is used by zio_done() when an I/O fails + * and we want to give back the block we just allocated. + * This handles both normal blocks and gang blocks. + */ +static void +zio_dva_unallocate(zio_t *zio, zio_gang_node_t *gn, blkptr_t *bp) +{ + spa_t *spa = zio->io_spa; + boolean_t now = !(zio->io_flags & ZIO_FLAG_IO_REWRITE); + + ASSERT(bp->blk_birth == zio->io_txg || BP_IS_HOLE(bp)); + + if (zio->io_bp == bp && !now) { + /* + * This is a rewrite for sync-to-convergence. + * We can't do a metaslab_free(NOW) because bp wasn't allocated + * during this sync pass, which means that metaslab_sync() + * already committed the allocation. + */ + ASSERT(DVA_EQUAL(BP_IDENTITY(bp), + BP_IDENTITY(&zio->io_bp_orig))); + ASSERT(spa_sync_pass(spa) > 1); + + if (BP_IS_GANG(bp) && gn == NULL) { + /* + * This is a gang leader whose gang header(s) we + * couldn't read now, so defer the free until later. + * The block should still be intact because without + * the headers, we'd never even start the rewrite. + */ + bplist_enqueue_deferred(&spa->spa_sync_bplist, bp); + return; + } + } + + if (!BP_IS_HOLE(bp)) + metaslab_free(spa, bp, bp->blk_birth, now); + + if (gn != NULL) { + for (int g = 0; g < SPA_GBH_NBLKPTRS; g++) { + zio_dva_unallocate(zio, gn->gn_child[g], + &gn->gn_gbh->zg_blkptr[g]); + } + } +} + +/* + * Try to allocate an intent log block. Return 0 on success, errno on failure. + */ +int +zio_alloc_blk(spa_t *spa, uint64_t size, blkptr_t *new_bp, blkptr_t *old_bp, + uint64_t txg) +{ + int error; + + error = metaslab_alloc(spa, spa->spa_log_class, size, + new_bp, 1, txg, old_bp, METASLAB_HINTBP_AVOID); + + if (error) + error = metaslab_alloc(spa, spa->spa_normal_class, size, + new_bp, 1, txg, old_bp, METASLAB_HINTBP_AVOID); + + if (error == 0) { + BP_SET_LSIZE(new_bp, size); + BP_SET_PSIZE(new_bp, size); + BP_SET_COMPRESS(new_bp, ZIO_COMPRESS_OFF); + BP_SET_CHECKSUM(new_bp, ZIO_CHECKSUM_ZILOG); + BP_SET_TYPE(new_bp, DMU_OT_INTENT_LOG); + BP_SET_LEVEL(new_bp, 0); + BP_SET_BYTEORDER(new_bp, ZFS_HOST_BYTEORDER); + } + + return (error); +} + +/* + * Free an intent log block. We know it can't be a gang block, so there's + * nothing to do except metaslab_free() it. + */ +void +zio_free_blk(spa_t *spa, blkptr_t *bp, uint64_t txg) +{ + ASSERT(!BP_IS_GANG(bp)); + + metaslab_free(spa, bp, txg, B_FALSE); +} + +/* + * ========================================================================== + * Read and write to physical devices + * ========================================================================== + */ + +static void +zio_vdev_io_probe_done(zio_t *zio) +{ + zio_t *dio; + vdev_t *vd = zio->io_private; + + mutex_enter(&vd->vdev_probe_lock); + ASSERT(vd->vdev_probe_zio == zio); + vd->vdev_probe_zio = NULL; + mutex_exit(&vd->vdev_probe_lock); + + while ((dio = zio->io_delegate_list) != NULL) { + zio->io_delegate_list = dio->io_delegate_next; + dio->io_delegate_next = NULL; + if (!vdev_accessible(vd, dio)) + dio->io_error = ENXIO; + zio_execute(dio); + } +} + +/* + * Probe the device to determine whether I/O failure is specific to this + * zio (e.g. a bad sector) or affects the entire vdev (e.g. unplugged). + */ +static int +zio_vdev_io_probe(zio_t *zio) +{ + vdev_t *vd = zio->io_vd; + zio_t *pio = NULL; + boolean_t created_pio = B_FALSE; + + /* + * Don't probe the probe. + */ + if (zio->io_flags & ZIO_FLAG_PROBE) + return (ZIO_PIPELINE_CONTINUE); + + /* + * To prevent 'probe storms' when a device fails, we create + * just one probe i/o at a time. All zios that want to probe + * this vdev will join the probe zio's io_delegate_list. + */ + mutex_enter(&vd->vdev_probe_lock); + + if ((pio = vd->vdev_probe_zio) == NULL) { + vd->vdev_probe_zio = pio = zio_root(zio->io_spa, + zio_vdev_io_probe_done, vd, ZIO_FLAG_CANFAIL); + created_pio = B_TRUE; + vd->vdev_probe_wanted = B_TRUE; + spa_async_request(zio->io_spa, SPA_ASYNC_PROBE); + } + + zio->io_delegate_next = pio->io_delegate_list; + pio->io_delegate_list = zio; + + mutex_exit(&vd->vdev_probe_lock); + + if (created_pio) { + zio_nowait(vdev_probe(vd, pio)); + zio_nowait(pio); + } + + return (ZIO_PIPELINE_STOP); +} + +static int +zio_vdev_io_start(zio_t *zio) +{ + vdev_t *vd = zio->io_vd; + uint64_t align; + spa_t *spa = zio->io_spa; + + ASSERT(zio->io_error == 0); + ASSERT(zio->io_child_error[ZIO_CHILD_VDEV] == 0); + + if (vd == NULL) { + if (!(zio->io_flags & ZIO_FLAG_CONFIG_WRITER)) + spa_config_enter(spa, SCL_ZIO, zio, RW_READER); + + /* + * The mirror_ops handle multiple DVAs in a single BP. + */ + return (vdev_mirror_ops.vdev_op_io_start(zio)); + } + + align = 1ULL << vd->vdev_top->vdev_ashift; + + if (P2PHASE(zio->io_size, align) != 0) { + uint64_t asize = P2ROUNDUP(zio->io_size, align); + char *abuf = zio_buf_alloc(asize); + ASSERT(vd == vd->vdev_top); + if (zio->io_type == ZIO_TYPE_WRITE) { + bcopy(zio->io_data, abuf, zio->io_size); + bzero(abuf + zio->io_size, asize - zio->io_size); + } + zio_push_transform(zio, abuf, asize, asize, zio_subblock); + } + + ASSERT(P2PHASE(zio->io_offset, align) == 0); + ASSERT(P2PHASE(zio->io_size, align) == 0); + ASSERT(zio->io_type != ZIO_TYPE_WRITE || (spa_mode & FWRITE)); + + if (vd->vdev_ops->vdev_op_leaf && + (zio->io_type == ZIO_TYPE_READ || zio->io_type == ZIO_TYPE_WRITE)) { + + if (zio->io_type == ZIO_TYPE_READ && vdev_cache_read(zio) == 0) + return (ZIO_PIPELINE_STOP); + + if ((zio = vdev_queue_io(zio)) == NULL) + return (ZIO_PIPELINE_STOP); + + if (!vdev_accessible(vd, zio)) { + zio->io_error = ENXIO; + zio_interrupt(zio); + return (ZIO_PIPELINE_STOP); + } + + } + + return (vd->vdev_ops->vdev_op_io_start(zio)); +} + +static int +zio_vdev_io_done(zio_t *zio) +{ + vdev_t *vd = zio->io_vd; + vdev_ops_t *ops = vd ? vd->vdev_ops : &vdev_mirror_ops; + boolean_t unexpected_error = B_FALSE; + + if (zio_wait_for_children(zio, ZIO_CHILD_VDEV, ZIO_WAIT_DONE)) + return (ZIO_PIPELINE_STOP); + + ASSERT(zio->io_type == ZIO_TYPE_READ || zio->io_type == ZIO_TYPE_WRITE); + + if (vd != NULL && vd->vdev_ops->vdev_op_leaf) { + + vdev_queue_io_done(zio); + + if (zio->io_type == ZIO_TYPE_WRITE) + vdev_cache_write(zio); + + if (zio_injection_enabled && zio->io_error == 0) + zio->io_error = zio_handle_device_injection(vd, EIO); + + if (zio_injection_enabled && zio->io_error == 0) + zio->io_error = zio_handle_label_injection(zio, EIO); + + if (zio->io_error) { + if (!vdev_accessible(vd, zio)) { + zio->io_error = ENXIO; + } else { + unexpected_error = B_TRUE; + } + } + } + + ops->vdev_op_io_done(zio); + + if (unexpected_error) + return (zio_vdev_io_probe(zio)); + + return (ZIO_PIPELINE_CONTINUE); +} + +static int +zio_vdev_io_assess(zio_t *zio) +{ + vdev_t *vd = zio->io_vd; + + if (zio_wait_for_children(zio, ZIO_CHILD_VDEV, ZIO_WAIT_DONE)) + return (ZIO_PIPELINE_STOP); + + if (vd == NULL && !(zio->io_flags & ZIO_FLAG_CONFIG_WRITER)) + spa_config_exit(zio->io_spa, SCL_ZIO, zio); + + if (zio->io_vsd != NULL) { + zio->io_vsd_free(zio); + zio->io_vsd = NULL; + } + + if (zio_injection_enabled && zio->io_error == 0) + zio->io_error = zio_handle_fault_injection(zio, EIO); + + /* + * If the I/O failed, determine whether we should attempt to retry it. + */ + if (zio->io_error && vd == NULL && + !(zio->io_flags & (ZIO_FLAG_DONT_RETRY | ZIO_FLAG_IO_RETRY))) { + ASSERT(!(zio->io_flags & ZIO_FLAG_DONT_QUEUE)); /* not a leaf */ + ASSERT(!(zio->io_flags & ZIO_FLAG_IO_BYPASS)); /* not a leaf */ + zio->io_error = 0; + zio->io_flags |= ZIO_FLAG_IO_RETRY | + ZIO_FLAG_DONT_CACHE | ZIO_FLAG_DONT_AGGREGATE; + zio->io_stage = ZIO_STAGE_VDEV_IO_START - 1; + zio_taskq_dispatch(zio, ZIO_TASKQ_ISSUE); + return (ZIO_PIPELINE_STOP); + } + + /* + * If we got an error on a leaf device, convert it to ENXIO + * if the device is not accessible at all. + */ + if (zio->io_error && vd != NULL && vd->vdev_ops->vdev_op_leaf && + !vdev_accessible(vd, zio)) + zio->io_error = ENXIO; + + /* + * If we can't write to an interior vdev (mirror or RAID-Z), + * set vdev_cant_write so that we stop trying to allocate from it. + */ + if (zio->io_error == ENXIO && zio->io_type == ZIO_TYPE_WRITE && + vd != NULL && !vd->vdev_ops->vdev_op_leaf) + vd->vdev_cant_write = B_TRUE; + + if (zio->io_error) + zio->io_pipeline = ZIO_INTERLOCK_PIPELINE; + + return (ZIO_PIPELINE_CONTINUE); +} + +void +zio_vdev_io_reissue(zio_t *zio) +{ + ASSERT(zio->io_stage == ZIO_STAGE_VDEV_IO_START); + ASSERT(zio->io_error == 0); + + zio->io_stage--; +} + +void +zio_vdev_io_redone(zio_t *zio) +{ + ASSERT(zio->io_stage == ZIO_STAGE_VDEV_IO_DONE); + + zio->io_stage--; +} + +void +zio_vdev_io_bypass(zio_t *zio) +{ + ASSERT(zio->io_stage == ZIO_STAGE_VDEV_IO_START); + ASSERT(zio->io_error == 0); + + zio->io_flags |= ZIO_FLAG_IO_BYPASS; + zio->io_stage = ZIO_STAGE_VDEV_IO_ASSESS - 1; +} + +/* + * ========================================================================== + * Generate and verify checksums + * ========================================================================== + */ +static int +zio_checksum_generate(zio_t *zio) +{ + blkptr_t *bp = zio->io_bp; + enum zio_checksum checksum; + + if (bp == NULL) { + /* + * This is zio_write_phys(). + * We're either generating a label checksum, or none at all. + */ + checksum = zio->io_prop.zp_checksum; + + if (checksum == ZIO_CHECKSUM_OFF) + return (ZIO_PIPELINE_CONTINUE); + + ASSERT(checksum == ZIO_CHECKSUM_LABEL); + } else { + if (BP_IS_GANG(bp) && zio->io_child_type == ZIO_CHILD_GANG) { + ASSERT(!IO_IS_ALLOCATING(zio)); + checksum = ZIO_CHECKSUM_GANG_HEADER; + } else { + checksum = BP_GET_CHECKSUM(bp); + } + } + + zio_checksum_compute(zio, checksum, zio->io_data, zio->io_size); + + return (ZIO_PIPELINE_CONTINUE); +} + +static int +zio_checksum_verify(zio_t *zio) +{ + blkptr_t *bp = zio->io_bp; + int error; + + if (bp == NULL) { + /* + * This is zio_read_phys(). + * We're either verifying a label checksum, or nothing at all. + */ + if (zio->io_prop.zp_checksum == ZIO_CHECKSUM_OFF) + return (ZIO_PIPELINE_CONTINUE); + + ASSERT(zio->io_prop.zp_checksum == ZIO_CHECKSUM_LABEL); + } + + if ((error = zio_checksum_error(zio)) != 0) { + zio->io_error = error; + if (!(zio->io_flags & ZIO_FLAG_SPECULATIVE)) { + zfs_ereport_post(FM_EREPORT_ZFS_CHECKSUM, + zio->io_spa, zio->io_vd, zio, 0, 0); + } + } + + return (ZIO_PIPELINE_CONTINUE); +} + +/* + * Called by RAID-Z to ensure we don't compute the checksum twice. + */ +void +zio_checksum_verified(zio_t *zio) +{ + zio->io_pipeline &= ~(1U << ZIO_STAGE_CHECKSUM_VERIFY); +} + +/* + * ========================================================================== + * Error rank. Error are ranked in the order 0, ENXIO, ECKSUM, EIO, other. + * An error of 0 indictes success. ENXIO indicates whole-device failure, + * which may be transient (e.g. unplugged) or permament. ECKSUM and EIO + * indicate errors that are specific to one I/O, and most likely permanent. + * Any other error is presumed to be worse because we weren't expecting it. + * ========================================================================== + */ +int +zio_worst_error(int e1, int e2) +{ + static int zio_error_rank[] = { 0, ENXIO, ECKSUM, EIO }; + int r1, r2; + + for (r1 = 0; r1 < sizeof (zio_error_rank) / sizeof (int); r1++) + if (e1 == zio_error_rank[r1]) + break; + + for (r2 = 0; r2 < sizeof (zio_error_rank) / sizeof (int); r2++) + if (e2 == zio_error_rank[r2]) + break; + + return (r1 > r2 ? e1 : e2); +} + +/* + * ========================================================================== + * I/O completion + * ========================================================================== + */ +static int +zio_ready(zio_t *zio) +{ + blkptr_t *bp = zio->io_bp; + zio_t *pio = zio->io_parent; + + if (zio->io_ready) { + if (BP_IS_GANG(bp) && + zio_wait_for_children(zio, ZIO_CHILD_GANG, ZIO_WAIT_READY)) + return (ZIO_PIPELINE_STOP); + + ASSERT(IO_IS_ALLOCATING(zio)); + ASSERT(bp->blk_birth == zio->io_txg || BP_IS_HOLE(bp)); + ASSERT(zio->io_children[ZIO_CHILD_GANG][ZIO_WAIT_READY] == 0); + + zio->io_ready(zio); + } + + if (bp != NULL && bp != &zio->io_bp_copy) + zio->io_bp_copy = *bp; + + if (zio->io_error) + zio->io_pipeline = ZIO_INTERLOCK_PIPELINE; + + if (pio != NULL) + zio_notify_parent(pio, zio, ZIO_WAIT_READY); + + return (ZIO_PIPELINE_CONTINUE); +} + +static int +zio_done(zio_t *zio) +{ + spa_t *spa = zio->io_spa; + zio_t *pio = zio->io_parent; + zio_t *lio = zio->io_logical; + blkptr_t *bp = zio->io_bp; + vdev_t *vd = zio->io_vd; + uint64_t psize = zio->io_size; + + /* + * If our of children haven't all completed, + * wait for them and then repeat this pipeline stage. + */ + if (zio_wait_for_children(zio, ZIO_CHILD_VDEV, ZIO_WAIT_DONE) || + zio_wait_for_children(zio, ZIO_CHILD_GANG, ZIO_WAIT_DONE) || + zio_wait_for_children(zio, ZIO_CHILD_LOGICAL, ZIO_WAIT_DONE)) + return (ZIO_PIPELINE_STOP); + + for (int c = 0; c < ZIO_CHILD_TYPES; c++) + for (int w = 0; w < ZIO_WAIT_TYPES; w++) + ASSERT(zio->io_children[c][w] == 0); + + if (bp != NULL) { + ASSERT(bp->blk_pad[0] == 0); + ASSERT(bp->blk_pad[1] == 0); + ASSERT(bp->blk_pad[2] == 0); + ASSERT(bcmp(bp, &zio->io_bp_copy, sizeof (blkptr_t)) == 0 || + (pio != NULL && bp == pio->io_bp)); + if (zio->io_type == ZIO_TYPE_WRITE && !BP_IS_HOLE(bp) && + !(zio->io_flags & ZIO_FLAG_IO_REPAIR)) { + ASSERT(!BP_SHOULD_BYTESWAP(bp)); + ASSERT3U(zio->io_prop.zp_ndvas, <=, BP_GET_NDVAS(bp)); + ASSERT(BP_COUNT_GANG(bp) == 0 || + (BP_COUNT_GANG(bp) == BP_GET_NDVAS(bp))); + } + } + + /* + * If there were child vdev or gang errors, they apply to us now. + */ + zio_inherit_child_errors(zio, ZIO_CHILD_VDEV); + zio_inherit_child_errors(zio, ZIO_CHILD_GANG); + + zio_pop_transforms(zio); /* note: may set zio->io_error */ + + vdev_stat_update(zio, psize); + + if (zio->io_error) { + /* + * If this I/O is attached to a particular vdev, + * generate an error message describing the I/O failure + * at the block level. We ignore these errors if the + * device is currently unavailable. + */ + if (zio->io_error != ECKSUM && vd != NULL && !vdev_is_dead(vd)) + zfs_ereport_post(FM_EREPORT_ZFS_IO, spa, vd, zio, 0, 0); + + if ((zio->io_error == EIO || + !(zio->io_flags & ZIO_FLAG_SPECULATIVE)) && zio == lio) { + /* + * For logical I/O requests, tell the SPA to log the + * error and generate a logical data ereport. + */ + spa_log_error(spa, zio); + zfs_ereport_post(FM_EREPORT_ZFS_DATA, spa, NULL, zio, + 0, 0); + } + } + + if (zio->io_error && zio == lio) { + /* + * Determine whether zio should be reexecuted. This will + * propagate all the way to the root via zio_notify_parent(). + */ + ASSERT(vd == NULL && bp != NULL); + + if (IO_IS_ALLOCATING(zio)) + if (zio->io_error != ENOSPC) + zio->io_reexecute |= ZIO_REEXECUTE_NOW; + else + zio->io_reexecute |= ZIO_REEXECUTE_SUSPEND; + + if ((zio->io_type == ZIO_TYPE_READ || + zio->io_type == ZIO_TYPE_FREE) && + zio->io_error == ENXIO && + spa_get_failmode(spa) != ZIO_FAILURE_MODE_CONTINUE) + zio->io_reexecute |= ZIO_REEXECUTE_SUSPEND; + + if (!(zio->io_flags & ZIO_FLAG_CANFAIL) && !zio->io_reexecute) + zio->io_reexecute |= ZIO_REEXECUTE_SUSPEND; + } + + /* + * If there were logical child errors, they apply to us now. + * We defer this until now to avoid conflating logical child + * errors with errors that happened to the zio itself when + * updating vdev stats and reporting FMA events above. + */ + zio_inherit_child_errors(zio, ZIO_CHILD_LOGICAL); + + if (zio->io_reexecute) { + /* + * This is a logical I/O that wants to reexecute. + * + * Reexecute is top-down. When an i/o fails, if it's not + * the root, it simply notifies its parent and sticks around. + * The parent, seeing that it still has children in zio_done(), + * does the same. This percolates all the way up to the root. + * The root i/o will reexecute or suspend the entire tree. + * + * This approach ensures that zio_reexecute() honors + * all the original i/o dependency relationships, e.g. + * parents not executing until children are ready. + */ + ASSERT(zio->io_child_type == ZIO_CHILD_LOGICAL); + + if (IO_IS_ALLOCATING(zio)) + zio_dva_unallocate(zio, zio->io_gang_tree, bp); + + zio_gang_tree_free(&zio->io_gang_tree); + + if (pio != NULL) { + /* + * We're not a root i/o, so there's nothing to do + * but notify our parent. Don't propagate errors + * upward since we haven't permanently failed yet. + */ + zio->io_flags |= ZIO_FLAG_DONT_PROPAGATE; + zio_notify_parent(pio, zio, ZIO_WAIT_DONE); + } else if (zio->io_reexecute & ZIO_REEXECUTE_SUSPEND) { + /* + * We'd fail again if we reexecuted now, so suspend + * until conditions improve (e.g. device comes online). + */ + zio_suspend(spa, zio); + } else { + /* + * Reexecution is potentially a huge amount of work. + * Hand it off to the otherwise-unused claim taskq. + */ + (void) taskq_dispatch( + spa->spa_zio_taskq[ZIO_TYPE_CLAIM][ZIO_TASKQ_ISSUE], + (task_func_t *)zio_reexecute, zio, TQ_SLEEP); + } + return (ZIO_PIPELINE_STOP); + } + + ASSERT(zio->io_child == NULL); + ASSERT(zio->io_reexecute == 0); + ASSERT(zio->io_error == 0 || (zio->io_flags & ZIO_FLAG_CANFAIL)); + + if (zio->io_done) + zio->io_done(zio); + + zio_gang_tree_free(&zio->io_gang_tree); + + ASSERT(zio->io_delegate_list == NULL); + ASSERT(zio->io_delegate_next == NULL); + + if (pio != NULL) { + zio_remove_child(pio, zio); + zio_notify_parent(pio, zio, ZIO_WAIT_DONE); + } + + if (zio->io_waiter != NULL) { + mutex_enter(&zio->io_lock); + zio->io_executor = NULL; + cv_broadcast(&zio->io_cv); + mutex_exit(&zio->io_lock); + } else { + zio_destroy(zio); + } + + return (ZIO_PIPELINE_STOP); +} + +/* + * ========================================================================== + * I/O pipeline definition + * ========================================================================== + */ +static zio_pipe_stage_t *zio_pipeline[ZIO_STAGES] = { + NULL, + zio_issue_async, + zio_read_bp_init, + zio_write_bp_init, + zio_checksum_generate, + zio_gang_assemble, + zio_gang_issue, + zio_dva_allocate, + zio_dva_free, + zio_dva_claim, + zio_ready, + zio_vdev_io_start, + zio_vdev_io_done, + zio_vdev_io_assess, + zio_checksum_verify, + zio_done +}; |