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-rw-r--r--uts/common/fs/zfs/zio.c2952
1 files changed, 2952 insertions, 0 deletions
diff --git a/uts/common/fs/zfs/zio.c b/uts/common/fs/zfs/zio.c
new file mode 100644
index 000000000000..eb509c5911f7
--- /dev/null
+++ b/uts/common/fs/zfs/zio.c
@@ -0,0 +1,2952 @@
+/*
+ * 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 (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
+ */
+
+#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>
+#include <sys/dmu_objset.h>
+#include <sys/arc.h>
+#include <sys/ddt.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 */
+ 0, /* ZIO_PRIORITY_LOG_WRITE */
+ 1, /* ZIO_PRIORITY_CACHE_FILL */
+ 1, /* ZIO_PRIORITY_AGG */
+ 4, /* ZIO_PRIORITY_FREE */
+ 4, /* ZIO_PRIORITY_ASYNC_WRITE */
+ 6, /* ZIO_PRIORITY_ASYNC_READ */
+ 10, /* ZIO_PRIORITY_RESILVER */
+ 20, /* ZIO_PRIORITY_SCRUB */
+ 2, /* ZIO_PRIORITY_DDT_PREFETCH */
+};
+
+/*
+ * ==========================================================================
+ * I/O type descriptions
+ * ==========================================================================
+ */
+char *zio_type_name[ZIO_TYPES] = {
+ "zio_null", "zio_read", "zio_write", "zio_free", "zio_claim",
+ "zio_ioctl"
+};
+
+/*
+ * ==========================================================================
+ * I/O kmem caches
+ * ==========================================================================
+ */
+kmem_cache_t *zio_cache;
+kmem_cache_t *zio_link_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 & ZIO_STAGE_DVA_ALLOCATE)
+
+boolean_t zio_requeue_io_start_cut_in_line = B_TRUE;
+
+#ifdef ZFS_DEBUG
+int zio_buf_debug_limit = 16384;
+#else
+int zio_buf_debug_limit = 0;
+#endif
+
+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);
+ zio_link_cache = kmem_cache_create("zio_link_cache",
+ sizeof (zio_link_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;
+ size_t cflags = (size > zio_buf_debug_limit) ? KMC_NODEBUG : 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, cflags);
+
+ /*
+ * Since zio_data bufs do not appear in crash dumps, we
+ * pass KMC_NOTOUCH so that no allocator metadata is
+ * stored with the buffers.
+ */
+ (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,
+ cflags | KMC_NOTOUCH);
+ }
+ }
+
+ 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_link_cache);
+ 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);
+
+ if (zt->zt_bufsize != 0)
+ 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, data, zio->io_size, size) != 0)
+ zio->io_error = EIO;
+}
+
+/*
+ * ==========================================================================
+ * I/O parent/child relationships and pipeline interlocks
+ * ==========================================================================
+ */
+/*
+ * NOTE - Callers to zio_walk_parents() and zio_walk_children must
+ * continue calling these functions until they return NULL.
+ * Otherwise, the next caller will pick up the list walk in
+ * some indeterminate state. (Otherwise every caller would
+ * have to pass in a cookie to keep the state represented by
+ * io_walk_link, which gets annoying.)
+ */
+zio_t *
+zio_walk_parents(zio_t *cio)
+{
+ zio_link_t *zl = cio->io_walk_link;
+ list_t *pl = &cio->io_parent_list;
+
+ zl = (zl == NULL) ? list_head(pl) : list_next(pl, zl);
+ cio->io_walk_link = zl;
+
+ if (zl == NULL)
+ return (NULL);
+
+ ASSERT(zl->zl_child == cio);
+ return (zl->zl_parent);
+}
+
+zio_t *
+zio_walk_children(zio_t *pio)
+{
+ zio_link_t *zl = pio->io_walk_link;
+ list_t *cl = &pio->io_child_list;
+
+ zl = (zl == NULL) ? list_head(cl) : list_next(cl, zl);
+ pio->io_walk_link = zl;
+
+ if (zl == NULL)
+ return (NULL);
+
+ ASSERT(zl->zl_parent == pio);
+ return (zl->zl_child);
+}
+
+zio_t *
+zio_unique_parent(zio_t *cio)
+{
+ zio_t *pio = zio_walk_parents(cio);
+
+ VERIFY(zio_walk_parents(cio) == NULL);
+ return (pio);
+}
+
+void
+zio_add_child(zio_t *pio, zio_t *cio)
+{
+ zio_link_t *zl = kmem_cache_alloc(zio_link_cache, KM_SLEEP);
+
+ /*
+ * 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(cio->io_child_type <= pio->io_child_type);
+
+ zl->zl_parent = pio;
+ zl->zl_child = cio;
+
+ mutex_enter(&cio->io_lock);
+ mutex_enter(&pio->io_lock);
+
+ ASSERT(pio->io_state[ZIO_WAIT_DONE] == 0);
+
+ for (int w = 0; w < ZIO_WAIT_TYPES; w++)
+ pio->io_children[cio->io_child_type][w] += !cio->io_state[w];
+
+ list_insert_head(&pio->io_child_list, zl);
+ list_insert_head(&cio->io_parent_list, zl);
+
+ pio->io_child_count++;
+ cio->io_parent_count++;
+
+ mutex_exit(&pio->io_lock);
+ mutex_exit(&cio->io_lock);
+}
+
+static void
+zio_remove_child(zio_t *pio, zio_t *cio, zio_link_t *zl)
+{
+ ASSERT(zl->zl_parent == pio);
+ ASSERT(zl->zl_child == cio);
+
+ mutex_enter(&cio->io_lock);
+ mutex_enter(&pio->io_lock);
+
+ list_remove(&pio->io_child_list, zl);
+ list_remove(&cio->io_parent_list, zl);
+
+ pio->io_child_count--;
+ cio->io_parent_count--;
+
+ mutex_exit(&pio->io_lock);
+ mutex_exit(&cio->io_lock);
+
+ kmem_cache_free(zio_link_cache, zl);
+}
+
+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 >>= 1;
+ 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, const blkptr_t *bp,
+ void *data, uint64_t size, zio_done_func_t *done, void *private,
+ zio_type_t type, int priority, enum zio_flag flags,
+ vdev_t *vd, uint64_t offset, const zbookmark_t *zb,
+ enum zio_stage stage, enum zio_stage 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);
+
+ list_create(&zio->io_parent_list, sizeof (zio_link_t),
+ offsetof(zio_link_t, zl_parent_node));
+ list_create(&zio->io_child_list, sizeof (zio_link_t),
+ offsetof(zio_link_t, zl_child_node));
+
+ 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 if (flags & ZIO_FLAG_DDT_CHILD)
+ zio->io_child_type = ZIO_CHILD_DDT;
+ else
+ zio->io_child_type = ZIO_CHILD_LOGICAL;
+
+ if (bp != NULL) {
+ zio->io_bp = (blkptr_t *)bp;
+ zio->io_bp_copy = *bp;
+ zio->io_bp_orig = *bp;
+ if (type != ZIO_TYPE_WRITE ||
+ zio->io_child_type == ZIO_CHILD_DDT)
+ zio->io_bp = &zio->io_bp_copy; /* so caller can free */
+ if (zio->io_child_type == ZIO_CHILD_LOGICAL)
+ zio->io_logical = zio;
+ if (zio->io_child_type > ZIO_CHILD_GANG && BP_IS_GANG(bp))
+ pipeline |= ZIO_GANG_STAGES;
+ }
+
+ zio->io_spa = spa;
+ zio->io_txg = txg;
+ 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_data = zio->io_data = data;
+ zio->io_orig_size = zio->io_size = size;
+ zio->io_orig_flags = zio->io_flags = flags;
+ zio->io_orig_stage = zio->io_stage = stage;
+ zio->io_orig_pipeline = zio->io_pipeline = pipeline;
+
+ zio->io_state[ZIO_WAIT_READY] = (stage >= ZIO_STAGE_READY);
+ zio->io_state[ZIO_WAIT_DONE] = (stage >= ZIO_STAGE_DONE);
+
+ if (zb != NULL)
+ zio->io_bookmark = *zb;
+
+ if (pio != NULL) {
+ if (zio->io_logical == NULL)
+ zio->io_logical = pio->io_logical;
+ if (zio->io_child_type == ZIO_CHILD_GANG)
+ zio->io_gang_leader = pio->io_gang_leader;
+ zio_add_child(pio, zio);
+ }
+
+ return (zio);
+}
+
+static void
+zio_destroy(zio_t *zio)
+{
+ list_destroy(&zio->io_parent_list);
+ list_destroy(&zio->io_child_list);
+ mutex_destroy(&zio->io_lock);
+ cv_destroy(&zio->io_cv);
+ kmem_cache_free(zio_cache, zio);
+}
+
+zio_t *
+zio_null(zio_t *pio, spa_t *spa, vdev_t *vd, zio_done_func_t *done,
+ void *private, enum zio_flag flags)
+{
+ zio_t *zio;
+
+ zio = zio_create(pio, spa, 0, NULL, NULL, 0, done, private,
+ ZIO_TYPE_NULL, ZIO_PRIORITY_NOW, flags, vd, 0, NULL,
+ ZIO_STAGE_OPEN, ZIO_INTERLOCK_PIPELINE);
+
+ return (zio);
+}
+
+zio_t *
+zio_root(spa_t *spa, zio_done_func_t *done, void *private, enum zio_flag flags)
+{
+ return (zio_null(NULL, spa, NULL, 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, enum zio_flag flags, const zbookmark_t *zb)
+{
+ zio_t *zio;
+
+ zio = zio_create(pio, spa, BP_PHYSICAL_BIRTH(bp), bp,
+ data, size, done, private,
+ ZIO_TYPE_READ, priority, flags, NULL, 0, zb,
+ ZIO_STAGE_OPEN, (flags & ZIO_FLAG_DDT_CHILD) ?
+ ZIO_DDT_CHILD_READ_PIPELINE : ZIO_READ_PIPELINE);
+
+ return (zio);
+}
+
+zio_t *
+zio_write(zio_t *pio, spa_t *spa, uint64_t txg, blkptr_t *bp,
+ void *data, uint64_t size, const zio_prop_t *zp,
+ zio_done_func_t *ready, zio_done_func_t *done, void *private,
+ int priority, enum zio_flag 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_copies > 0 &&
+ zp->zp_copies <= spa_max_replication(spa) &&
+ zp->zp_dedup <= 1 &&
+ zp->zp_dedup_verify <= 1);
+
+ zio = zio_create(pio, spa, txg, bp, data, size, done, private,
+ ZIO_TYPE_WRITE, priority, flags, NULL, 0, zb,
+ ZIO_STAGE_OPEN, (flags & ZIO_FLAG_DDT_CHILD) ?
+ ZIO_DDT_CHILD_WRITE_PIPELINE : 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,
+ enum zio_flag 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);
+}
+
+void
+zio_write_override(zio_t *zio, blkptr_t *bp, int copies)
+{
+ ASSERT(zio->io_type == ZIO_TYPE_WRITE);
+ ASSERT(zio->io_child_type == ZIO_CHILD_LOGICAL);
+ ASSERT(zio->io_stage == ZIO_STAGE_OPEN);
+ ASSERT(zio->io_txg == spa_syncing_txg(zio->io_spa));
+
+ zio->io_prop.zp_copies = copies;
+ zio->io_bp_override = bp;
+}
+
+void
+zio_free(spa_t *spa, uint64_t txg, const blkptr_t *bp)
+{
+ bplist_append(&spa->spa_free_bplist[txg & TXG_MASK], bp);
+}
+
+zio_t *
+zio_free_sync(zio_t *pio, spa_t *spa, uint64_t txg, const blkptr_t *bp,
+ enum zio_flag flags)
+{
+ zio_t *zio;
+
+ dprintf_bp(bp, "freeing in txg %llu, pass %u",
+ (longlong_t)txg, spa->spa_sync_pass);
+
+ ASSERT(!BP_IS_HOLE(bp));
+ ASSERT(spa_syncing_txg(spa) == txg);
+ ASSERT(spa_sync_pass(spa) <= SYNC_PASS_DEFERRED_FREE);
+
+ zio = zio_create(pio, spa, txg, bp, NULL, BP_GET_PSIZE(bp),
+ NULL, NULL, 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, const blkptr_t *bp,
+ zio_done_func_t *done, void *private, enum zio_flag 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.
+ * If txg == 0 we just verify that the block is claimable.
+ */
+ ASSERT3U(spa->spa_uberblock.ub_rootbp.blk_birth, <, spa_first_txg(spa));
+ ASSERT(txg == spa_first_txg(spa) || txg == 0);
+ ASSERT(!BP_GET_DEDUP(bp) || !spa_writeable(spa)); /* zdb(1M) */
+
+ 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, enum zio_flag 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, 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, enum zio_flag 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, enum zio_flag 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_eck) {
+ /*
+ * zec 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, enum zio_flag flags,
+ zio_done_func_t *done, void *private)
+{
+ enum zio_stage 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 |= ZIO_STAGE_CHECKSUM_VERIFY;
+ pio->io_pipeline &= ~ZIO_STAGE_CHECKSUM_VERIFY;
+ }
+
+ if (vd->vdev_children == 0)
+ offset += VDEV_LABEL_START_SIZE;
+
+ flags |= ZIO_VDEV_CHILD_FLAGS(pio) | ZIO_FLAG_DONT_PROPAGATE;
+
+ /*
+ * If we've decided to do a repair, the write is not speculative --
+ * even if the original read was.
+ */
+ if (flags & ZIO_FLAG_IO_REPAIR)
+ flags &= ~ZIO_FLAG_SPECULATIVE;
+
+ zio = zio_create(pio, pio->io_spa, pio->io_txg, bp, data, size,
+ done, private, type, priority, 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, enum zio_flag 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));
+}
+
+void
+zio_shrink(zio_t *zio, uint64_t size)
+{
+ ASSERT(zio->io_executor == NULL);
+ ASSERT(zio->io_orig_size == zio->io_size);
+ ASSERT(size <= zio->io_size);
+
+ /*
+ * We don't shrink for raidz because of problems with the
+ * reconstruction when reading back less than the block size.
+ * Note, BP_IS_RAIDZ() assumes no compression.
+ */
+ ASSERT(BP_GET_COMPRESS(zio->io_bp) == ZIO_COMPRESS_OFF);
+ if (!BP_IS_RAIDZ(zio->io_bp))
+ zio->io_orig_size = zio->io_size = size;
+}
+
+/*
+ * ==========================================================================
+ * 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_child_type == ZIO_CHILD_LOGICAL &&
+ !(zio->io_flags & ZIO_FLAG_RAW)) {
+ uint64_t psize = BP_GET_PSIZE(bp);
+ void *cbuf = zio_buf_alloc(psize);
+
+ zio_push_transform(zio, cbuf, psize, psize, zio_decompress);
+ }
+
+ if (!dmu_ot[BP_GET_TYPE(bp)].ot_metadata && BP_GET_LEVEL(bp) == 0)
+ zio->io_flags |= ZIO_FLAG_DONT_CACHE;
+
+ if (BP_GET_TYPE(bp) == DMU_OT_DDT_ZAP)
+ zio->io_flags |= ZIO_FLAG_DONT_CACHE;
+
+ if (BP_GET_DEDUP(bp) && zio->io_child_type == ZIO_CHILD_LOGICAL)
+ zio->io_pipeline = ZIO_DDT_READ_PIPELINE;
+
+ return (ZIO_PIPELINE_CONTINUE);
+}
+
+static int
+zio_write_bp_init(zio_t *zio)
+{
+ spa_t *spa = zio->io_spa;
+ zio_prop_t *zp = &zio->io_prop;
+ enum zio_compress compress = zp->zp_compress;
+ blkptr_t *bp = zio->io_bp;
+ uint64_t lsize = zio->io_size;
+ uint64_t psize = lsize;
+ 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(zio->io_child_type != ZIO_CHILD_DDT);
+
+ if (zio->io_bp_override) {
+ ASSERT(bp->blk_birth != zio->io_txg);
+ ASSERT(BP_GET_DEDUP(zio->io_bp_override) == 0);
+
+ *bp = *zio->io_bp_override;
+ zio->io_pipeline = ZIO_INTERLOCK_PIPELINE;
+
+ if (BP_IS_HOLE(bp) || !zp->zp_dedup)
+ return (ZIO_PIPELINE_CONTINUE);
+
+ ASSERT(zio_checksum_table[zp->zp_checksum].ci_dedup ||
+ zp->zp_dedup_verify);
+
+ if (BP_GET_CHECKSUM(bp) == zp->zp_checksum) {
+ BP_SET_DEDUP(bp, 1);
+ zio->io_pipeline |= ZIO_STAGE_DDT_WRITE;
+ return (ZIO_PIPELINE_CONTINUE);
+ }
+ zio->io_bp_override = NULL;
+ BP_ZERO(bp);
+ }
+
+ 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(spa);
+
+ ASSERT(zio->io_txg == spa_syncing_txg(spa));
+ ASSERT(zio->io_child_type == ZIO_CHILD_LOGICAL);
+ ASSERT(!BP_GET_DEDUP(bp));
+
+ if (pass > SYNC_PASS_DONT_COMPRESS)
+ compress = ZIO_COMPRESS_OFF;
+
+ /* Make sure someone doesn't change their mind on overwrites */
+ ASSERT(MIN(zp->zp_copies + BP_IS_GANG(bp),
+ spa_max_replication(spa)) == BP_GET_NDVAS(bp));
+ }
+
+ if (compress != ZIO_COMPRESS_OFF) {
+ void *cbuf = zio_buf_alloc(lsize);
+ psize = zio_compress_data(compress, zio->io_data, cbuf, lsize);
+ if (psize == 0 || psize == lsize) {
+ compress = ZIO_COMPRESS_OFF;
+ zio_buf_free(cbuf, lsize);
+ } else {
+ ASSERT(psize < lsize);
+ zio_push_transform(zio, cbuf, psize, lsize, 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) == psize &&
+ pass > SYNC_PASS_REWRITE) {
+ ASSERT(psize != 0);
+ enum zio_stage 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 (psize == 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, psize);
+ 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_DEDUP(bp, zp->zp_dedup);
+ BP_SET_BYTEORDER(bp, ZFS_HOST_BYTEORDER);
+ if (zp->zp_dedup) {
+ ASSERT(zio->io_child_type == ZIO_CHILD_LOGICAL);
+ ASSERT(!(zio->io_flags & ZIO_FLAG_IO_REWRITE));
+ zio->io_pipeline = ZIO_DDT_WRITE_PIPELINE;
+ }
+ }
+
+ return (ZIO_PIPELINE_CONTINUE);
+}
+
+static int
+zio_free_bp_init(zio_t *zio)
+{
+ blkptr_t *bp = zio->io_bp;
+
+ if (zio->io_child_type == ZIO_CHILD_LOGICAL) {
+ if (BP_GET_DEDUP(bp))
+ zio->io_pipeline = ZIO_DDT_FREE_PIPELINE;
+ }
+
+ return (ZIO_PIPELINE_CONTINUE);
+}
+
+/*
+ * ==========================================================================
+ * Execute the I/O pipeline
+ * ==========================================================================
+ */
+
+static void
+zio_taskq_dispatch(zio_t *zio, enum zio_taskq_type q, boolean_t cutinline)
+{
+ spa_t *spa = zio->io_spa;
+ zio_type_t t = zio->io_type;
+ int flags = TQ_SLEEP | (cutinline ? TQ_FRONT : 0);
+
+ /*
+ * If we're a config writer or a probe, 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 | ZIO_FLAG_PROBE))
+ 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;
+
+ /*
+ * If this is a high priority I/O, then use the high priority taskq.
+ */
+ if (zio->io_priority == ZIO_PRIORITY_NOW &&
+ spa->spa_zio_taskq[t][q + 1] != NULL)
+ q++;
+
+ ASSERT3U(q, <, ZIO_TASKQ_TYPES);
+ (void) taskq_dispatch(spa->spa_zio_taskq[t][q],
+ (task_func_t *)zio_execute, zio, flags);
+}
+
+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, B_FALSE);
+
+ return (ZIO_PIPELINE_STOP);
+}
+
+void
+zio_interrupt(zio_t *zio)
+{
+ zio_taskq_dispatch(zio, ZIO_TASKQ_INTERRUPT, B_FALSE);
+}
+
+/*
+ * 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[];
+
+void
+zio_execute(zio_t *zio)
+{
+ zio->io_executor = curthread;
+
+ while (zio->io_stage < ZIO_STAGE_DONE) {
+ enum zio_stage pipeline = zio->io_pipeline;
+ enum zio_stage stage = zio->io_stage;
+ int rv;
+
+ ASSERT(!MUTEX_HELD(&zio->io_lock));
+ ASSERT(ISP2(stage));
+ ASSERT(zio->io_stall == NULL);
+
+ do {
+ stage <<= 1;
+ } while ((stage & pipeline) == 0);
+
+ ASSERT(stage <= ZIO_STAGE_DONE);
+
+ /*
+ * If we are in interrupt context and this pipeline stage
+ * will grab a config lock that is held across I/O,
+ * or may wait for an I/O that needs an interrupt thread
+ * to complete, issue async to avoid deadlock.
+ *
+ * For VDEV_IO_START, we cut in line so that the io will
+ * be sent to disk promptly.
+ */
+ if ((stage & ZIO_BLOCKING_STAGES) && zio->io_vd == NULL &&
+ zio_taskq_member(zio, ZIO_TASKQ_INTERRUPT)) {
+ boolean_t cut = (stage == ZIO_STAGE_VDEV_IO_START) ?
+ zio_requeue_io_start_cut_in_line : B_FALSE;
+ zio_taskq_dispatch(zio, ZIO_TASKQ_ISSUE, cut);
+ return;
+ }
+
+ zio->io_stage = stage;
+ rv = zio_pipeline[highbit(stage) - 1](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_child_type == ZIO_CHILD_LOGICAL &&
+ zio_unique_parent(zio) == NULL) {
+ /*
+ * This is a logical async I/O with no parent to wait for it.
+ * We add it to the spa_async_root_zio "Godfather" I/O which
+ * will ensure they complete prior to unloading the pool.
+ */
+ spa_t *spa = zio->io_spa;
+
+ zio_add_child(spa->spa_async_zio_root, zio);
+ }
+
+ zio_execute(zio);
+}
+
+/*
+ * ==========================================================================
+ * Reexecute or suspend/resume failed I/O
+ * ==========================================================================
+ */
+
+static void
+zio_reexecute(zio_t *pio)
+{
+ zio_t *cio, *cio_next;
+
+ ASSERT(pio->io_child_type == ZIO_CHILD_LOGICAL);
+ ASSERT(pio->io_orig_stage == ZIO_STAGE_OPEN);
+ ASSERT(pio->io_gang_leader == NULL);
+ ASSERT(pio->io_gang_tree == NULL);
+
+ 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 w = 0; w < ZIO_WAIT_TYPES; w++)
+ pio->io_state[w] = 0;
+ for (int c = 0; c < ZIO_CHILD_TYPES; c++)
+ pio->io_child_error[c] = 0;
+
+ if (IO_IS_ALLOCATING(pio))
+ BP_ZERO(pio->io_bp);
+
+ /*
+ * As we reexecute pio's children, new children could be created.
+ * New children go to the head of pio's io_child_list, however,
+ * so we will (correctly) not reexecute them. The key is that
+ * the remainder of pio's io_child_list, from 'cio_next' onward,
+ * cannot be affected by any side effects of reexecuting 'cio'.
+ */
+ for (cio = zio_walk_children(pio); cio != NULL; cio = cio_next) {
+ cio_next = zio_walk_children(pio);
+ mutex_enter(&pio->io_lock);
+ for (int w = 0; w < ZIO_WAIT_TYPES; w++)
+ pio->io_children[cio->io_child_type][w]++;
+ mutex_exit(&pio->io_lock);
+ zio_reexecute(cio);
+ }
+
+ /*
+ * Now that all children have been reexecuted, execute the parent.
+ * We don't reexecute "The Godfather" I/O here as it's the
+ * responsibility of the caller to wait on him.
+ */
+ if (!(pio->io_flags & ZIO_FLAG_GODFATHER))
+ 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,
+ ZIO_FLAG_CANFAIL | ZIO_FLAG_SPECULATIVE |
+ ZIO_FLAG_GODFATHER);
+
+ spa->spa_suspended = B_TRUE;
+
+ if (zio != NULL) {
+ ASSERT(!(zio->io_flags & ZIO_FLAG_GODFATHER));
+ ASSERT(zio != spa->spa_suspend_zio_root);
+ ASSERT(zio->io_child_type == ZIO_CHILD_LOGICAL);
+ ASSERT(zio_unique_parent(zio) == NULL);
+ ASSERT(zio->io_stage == ZIO_STAGE_DONE);
+ zio_add_child(spa->spa_suspend_zio_root, zio);
+ }
+
+ mutex_exit(&spa->spa_suspend_lock);
+}
+
+int
+zio_resume(spa_t *spa)
+{
+ zio_t *pio;
+
+ /*
+ * 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 (0);
+
+ zio_reexecute(pio);
+ return (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_gang_leader->io_gang_tree) {
+ zio_checksum_compute(zio, BP_GET_CHECKSUM(bp),
+ data, BP_GET_PSIZE(bp));
+ }
+ /*
+ * If we are here to damage data for testing purposes,
+ * leave the GBH alone so that we can detect the damage.
+ */
+ if (pio->io_gang_leader->io_flags & ZIO_FLAG_INDUCE_DAMAGE)
+ zio->io_pipeline &= ~ZIO_VDEV_IO_STAGES;
+ } 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_sync(pio, pio->io_spa, pio->io_txg, bp,
+ 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 *gio, blkptr_t *bp, zio_gang_node_t **gnpp)
+{
+ zio_gang_node_t *gn = zio_gang_node_alloc(gnpp);
+
+ ASSERT(gio->io_gang_leader == gio);
+ ASSERT(BP_IS_GANG(bp));
+
+ zio_nowait(zio_read(gio, gio->io_spa, bp, gn->gn_gbh,
+ SPA_GANGBLOCKSIZE, zio_gang_tree_assemble_done, gn,
+ gio->io_priority, ZIO_GANG_CHILD_FLAGS(gio), &gio->io_bookmark));
+}
+
+static void
+zio_gang_tree_assemble_done(zio_t *zio)
+{
+ zio_t *gio = zio->io_gang_leader;
+ zio_gang_node_t *gn = zio->io_private;
+ blkptr_t *bp = zio->io_bp;
+
+ ASSERT(gio == zio_unique_parent(zio));
+ ASSERT(zio->io_child_count == 0);
+
+ 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.zec_magic == ZEC_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(gio, 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 *gio = pio->io_gang_leader;
+ zio_t *zio;
+
+ ASSERT(BP_IS_GANG(bp) == !!gn);
+ ASSERT(BP_GET_CHECKSUM(bp) == BP_GET_CHECKSUM(gio->io_bp));
+ ASSERT(BP_GET_LSIZE(bp) == BP_GET_PSIZE(bp) || gn == gio->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[gio->io_type](pio, bp, gn, data);
+
+ if (gn != NULL) {
+ ASSERT(gn->gn_gbh->zg_tail.zec_magic == ZEC_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 == gio->io_gang_tree)
+ ASSERT3P((char *)gio->io_data + gio->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->io_gang_leader == NULL);
+ ASSERT(zio->io_child_type > ZIO_CHILD_GANG);
+
+ zio->io_gang_leader = zio;
+
+ zio_gang_tree_assemble(zio, bp, &zio->io_gang_tree);
+
+ return (ZIO_PIPELINE_CONTINUE);
+}
+
+static int
+zio_gang_issue(zio_t *zio)
+{
+ 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->io_gang_leader == zio);
+ ASSERT(zio->io_child_type > ZIO_CHILD_GANG);
+
+ if (zio->io_child_error[ZIO_CHILD_GANG] == 0)
+ zio_gang_tree_issue(zio, zio->io_gang_tree, bp, zio->io_data);
+ else
+ zio_gang_tree_free(&zio->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_unique_parent(zio);
+ zio_t *gio = zio->io_gang_leader;
+ 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_copies, ==, gio->io_prop.zp_copies);
+ ASSERT3U(zio->io_prop.zp_copies, <=, BP_GET_NDVAS(zio->io_bp));
+ ASSERT3U(pio->io_prop.zp_copies, <=, 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 *gio = pio->io_gang_leader;
+ 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 copies = gio->io_prop.zp_copies;
+ int gbh_copies = MIN(copies + 1, spa_max_replication(spa));
+ zio_prop_t zp;
+ int error;
+
+ error = metaslab_alloc(spa, spa_normal_class(spa), SPA_GANGBLOCKSIZE,
+ bp, gbh_copies, txg, pio == gio ? NULL : gio->io_bp,
+ METASLAB_HINTBP_FAVOR | METASLAB_GANG_HEADER);
+ if (error) {
+ pio->io_error = error;
+ return (ZIO_PIPELINE_CONTINUE);
+ }
+
+ if (pio == gio) {
+ gnpp = &gio->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 = gio->io_prop.zp_checksum;
+ zp.zp_compress = ZIO_COMPRESS_OFF;
+ zp.zp_type = DMU_OT_NONE;
+ zp.zp_level = 0;
+ zp.zp_copies = gio->io_prop.zp_copies;
+ zp.zp_dedup = 0;
+ zp.zp_dedup_verify = 0;
+
+ 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);
+}
+
+/*
+ * ==========================================================================
+ * Dedup
+ * ==========================================================================
+ */
+static void
+zio_ddt_child_read_done(zio_t *zio)
+{
+ blkptr_t *bp = zio->io_bp;
+ ddt_entry_t *dde = zio->io_private;
+ ddt_phys_t *ddp;
+ zio_t *pio = zio_unique_parent(zio);
+
+ mutex_enter(&pio->io_lock);
+ ddp = ddt_phys_select(dde, bp);
+ if (zio->io_error == 0)
+ ddt_phys_clear(ddp); /* this ddp doesn't need repair */
+ if (zio->io_error == 0 && dde->dde_repair_data == NULL)
+ dde->dde_repair_data = zio->io_data;
+ else
+ zio_buf_free(zio->io_data, zio->io_size);
+ mutex_exit(&pio->io_lock);
+}
+
+static int
+zio_ddt_read_start(zio_t *zio)
+{
+ blkptr_t *bp = zio->io_bp;
+
+ ASSERT(BP_GET_DEDUP(bp));
+ ASSERT(BP_GET_PSIZE(bp) == zio->io_size);
+ ASSERT(zio->io_child_type == ZIO_CHILD_LOGICAL);
+
+ if (zio->io_child_error[ZIO_CHILD_DDT]) {
+ ddt_t *ddt = ddt_select(zio->io_spa, bp);
+ ddt_entry_t *dde = ddt_repair_start(ddt, bp);
+ ddt_phys_t *ddp = dde->dde_phys;
+ ddt_phys_t *ddp_self = ddt_phys_select(dde, bp);
+ blkptr_t blk;
+
+ ASSERT(zio->io_vsd == NULL);
+ zio->io_vsd = dde;
+
+ if (ddp_self == NULL)
+ return (ZIO_PIPELINE_CONTINUE);
+
+ for (int p = 0; p < DDT_PHYS_TYPES; p++, ddp++) {
+ if (ddp->ddp_phys_birth == 0 || ddp == ddp_self)
+ continue;
+ ddt_bp_create(ddt->ddt_checksum, &dde->dde_key, ddp,
+ &blk);
+ zio_nowait(zio_read(zio, zio->io_spa, &blk,
+ zio_buf_alloc(zio->io_size), zio->io_size,
+ zio_ddt_child_read_done, dde, zio->io_priority,
+ ZIO_DDT_CHILD_FLAGS(zio) | ZIO_FLAG_DONT_PROPAGATE,
+ &zio->io_bookmark));
+ }
+ return (ZIO_PIPELINE_CONTINUE);
+ }
+
+ zio_nowait(zio_read(zio, zio->io_spa, bp,
+ zio->io_data, zio->io_size, NULL, NULL, zio->io_priority,
+ ZIO_DDT_CHILD_FLAGS(zio), &zio->io_bookmark));
+
+ return (ZIO_PIPELINE_CONTINUE);
+}
+
+static int
+zio_ddt_read_done(zio_t *zio)
+{
+ blkptr_t *bp = zio->io_bp;
+
+ if (zio_wait_for_children(zio, ZIO_CHILD_DDT, ZIO_WAIT_DONE))
+ return (ZIO_PIPELINE_STOP);
+
+ ASSERT(BP_GET_DEDUP(bp));
+ ASSERT(BP_GET_PSIZE(bp) == zio->io_size);
+ ASSERT(zio->io_child_type == ZIO_CHILD_LOGICAL);
+
+ if (zio->io_child_error[ZIO_CHILD_DDT]) {
+ ddt_t *ddt = ddt_select(zio->io_spa, bp);
+ ddt_entry_t *dde = zio->io_vsd;
+ if (ddt == NULL) {
+ ASSERT(spa_load_state(zio->io_spa) != SPA_LOAD_NONE);
+ return (ZIO_PIPELINE_CONTINUE);
+ }
+ if (dde == NULL) {
+ zio->io_stage = ZIO_STAGE_DDT_READ_START >> 1;
+ zio_taskq_dispatch(zio, ZIO_TASKQ_ISSUE, B_FALSE);
+ return (ZIO_PIPELINE_STOP);
+ }
+ if (dde->dde_repair_data != NULL) {
+ bcopy(dde->dde_repair_data, zio->io_data, zio->io_size);
+ zio->io_child_error[ZIO_CHILD_DDT] = 0;
+ }
+ ddt_repair_done(ddt, dde);
+ zio->io_vsd = NULL;
+ }
+
+ ASSERT(zio->io_vsd == NULL);
+
+ return (ZIO_PIPELINE_CONTINUE);
+}
+
+static boolean_t
+zio_ddt_collision(zio_t *zio, ddt_t *ddt, ddt_entry_t *dde)
+{
+ spa_t *spa = zio->io_spa;
+
+ /*
+ * Note: we compare the original data, not the transformed data,
+ * because when zio->io_bp is an override bp, we will not have
+ * pushed the I/O transforms. That's an important optimization
+ * because otherwise we'd compress/encrypt all dmu_sync() data twice.
+ */
+ for (int p = DDT_PHYS_SINGLE; p <= DDT_PHYS_TRIPLE; p++) {
+ zio_t *lio = dde->dde_lead_zio[p];
+
+ if (lio != NULL) {
+ return (lio->io_orig_size != zio->io_orig_size ||
+ bcmp(zio->io_orig_data, lio->io_orig_data,
+ zio->io_orig_size) != 0);
+ }
+ }
+
+ for (int p = DDT_PHYS_SINGLE; p <= DDT_PHYS_TRIPLE; p++) {
+ ddt_phys_t *ddp = &dde->dde_phys[p];
+
+ if (ddp->ddp_phys_birth != 0) {
+ arc_buf_t *abuf = NULL;
+ uint32_t aflags = ARC_WAIT;
+ blkptr_t blk = *zio->io_bp;
+ int error;
+
+ ddt_bp_fill(ddp, &blk, ddp->ddp_phys_birth);
+
+ ddt_exit(ddt);
+
+ error = arc_read_nolock(NULL, spa, &blk,
+ arc_getbuf_func, &abuf, ZIO_PRIORITY_SYNC_READ,
+ ZIO_FLAG_CANFAIL | ZIO_FLAG_SPECULATIVE,
+ &aflags, &zio->io_bookmark);
+
+ if (error == 0) {
+ if (arc_buf_size(abuf) != zio->io_orig_size ||
+ bcmp(abuf->b_data, zio->io_orig_data,
+ zio->io_orig_size) != 0)
+ error = EEXIST;
+ VERIFY(arc_buf_remove_ref(abuf, &abuf) == 1);
+ }
+
+ ddt_enter(ddt);
+ return (error != 0);
+ }
+ }
+
+ return (B_FALSE);
+}
+
+static void
+zio_ddt_child_write_ready(zio_t *zio)
+{
+ int p = zio->io_prop.zp_copies;
+ ddt_t *ddt = ddt_select(zio->io_spa, zio->io_bp);
+ ddt_entry_t *dde = zio->io_private;
+ ddt_phys_t *ddp = &dde->dde_phys[p];
+ zio_t *pio;
+
+ if (zio->io_error)
+ return;
+
+ ddt_enter(ddt);
+
+ ASSERT(dde->dde_lead_zio[p] == zio);
+
+ ddt_phys_fill(ddp, zio->io_bp);
+
+ while ((pio = zio_walk_parents(zio)) != NULL)
+ ddt_bp_fill(ddp, pio->io_bp, zio->io_txg);
+
+ ddt_exit(ddt);
+}
+
+static void
+zio_ddt_child_write_done(zio_t *zio)
+{
+ int p = zio->io_prop.zp_copies;
+ ddt_t *ddt = ddt_select(zio->io_spa, zio->io_bp);
+ ddt_entry_t *dde = zio->io_private;
+ ddt_phys_t *ddp = &dde->dde_phys[p];
+
+ ddt_enter(ddt);
+
+ ASSERT(ddp->ddp_refcnt == 0);
+ ASSERT(dde->dde_lead_zio[p] == zio);
+ dde->dde_lead_zio[p] = NULL;
+
+ if (zio->io_error == 0) {
+ while (zio_walk_parents(zio) != NULL)
+ ddt_phys_addref(ddp);
+ } else {
+ ddt_phys_clear(ddp);
+ }
+
+ ddt_exit(ddt);
+}
+
+static void
+zio_ddt_ditto_write_done(zio_t *zio)
+{
+ int p = DDT_PHYS_DITTO;
+ zio_prop_t *zp = &zio->io_prop;
+ blkptr_t *bp = zio->io_bp;
+ ddt_t *ddt = ddt_select(zio->io_spa, bp);
+ ddt_entry_t *dde = zio->io_private;
+ ddt_phys_t *ddp = &dde->dde_phys[p];
+ ddt_key_t *ddk = &dde->dde_key;
+
+ ddt_enter(ddt);
+
+ ASSERT(ddp->ddp_refcnt == 0);
+ ASSERT(dde->dde_lead_zio[p] == zio);
+ dde->dde_lead_zio[p] = NULL;
+
+ if (zio->io_error == 0) {
+ ASSERT(ZIO_CHECKSUM_EQUAL(bp->blk_cksum, ddk->ddk_cksum));
+ ASSERT(zp->zp_copies < SPA_DVAS_PER_BP);
+ ASSERT(zp->zp_copies == BP_GET_NDVAS(bp) - BP_IS_GANG(bp));
+ if (ddp->ddp_phys_birth != 0)
+ ddt_phys_free(ddt, ddk, ddp, zio->io_txg);
+ ddt_phys_fill(ddp, bp);
+ }
+
+ ddt_exit(ddt);
+}
+
+static int
+zio_ddt_write(zio_t *zio)
+{
+ spa_t *spa = zio->io_spa;
+ blkptr_t *bp = zio->io_bp;
+ uint64_t txg = zio->io_txg;
+ zio_prop_t *zp = &zio->io_prop;
+ int p = zp->zp_copies;
+ int ditto_copies;
+ zio_t *cio = NULL;
+ zio_t *dio = NULL;
+ ddt_t *ddt = ddt_select(spa, bp);
+ ddt_entry_t *dde;
+ ddt_phys_t *ddp;
+
+ ASSERT(BP_GET_DEDUP(bp));
+ ASSERT(BP_GET_CHECKSUM(bp) == zp->zp_checksum);
+ ASSERT(BP_IS_HOLE(bp) || zio->io_bp_override);
+
+ ddt_enter(ddt);
+ dde = ddt_lookup(ddt, bp, B_TRUE);
+ ddp = &dde->dde_phys[p];
+
+ if (zp->zp_dedup_verify && zio_ddt_collision(zio, ddt, dde)) {
+ /*
+ * If we're using a weak checksum, upgrade to a strong checksum
+ * and try again. If we're already using a strong checksum,
+ * we can't resolve it, so just convert to an ordinary write.
+ * (And automatically e-mail a paper to Nature?)
+ */
+ if (!zio_checksum_table[zp->zp_checksum].ci_dedup) {
+ zp->zp_checksum = spa_dedup_checksum(spa);
+ zio_pop_transforms(zio);
+ zio->io_stage = ZIO_STAGE_OPEN;
+ BP_ZERO(bp);
+ } else {
+ zp->zp_dedup = 0;
+ }
+ zio->io_pipeline = ZIO_WRITE_PIPELINE;
+ ddt_exit(ddt);
+ return (ZIO_PIPELINE_CONTINUE);
+ }
+
+ ditto_copies = ddt_ditto_copies_needed(ddt, dde, ddp);
+ ASSERT(ditto_copies < SPA_DVAS_PER_BP);
+
+ if (ditto_copies > ddt_ditto_copies_present(dde) &&
+ dde->dde_lead_zio[DDT_PHYS_DITTO] == NULL) {
+ zio_prop_t czp = *zp;
+
+ czp.zp_copies = ditto_copies;
+
+ /*
+ * If we arrived here with an override bp, we won't have run
+ * the transform stack, so we won't have the data we need to
+ * generate a child i/o. So, toss the override bp and restart.
+ * This is safe, because using the override bp is just an
+ * optimization; and it's rare, so the cost doesn't matter.
+ */
+ if (zio->io_bp_override) {
+ zio_pop_transforms(zio);
+ zio->io_stage = ZIO_STAGE_OPEN;
+ zio->io_pipeline = ZIO_WRITE_PIPELINE;
+ zio->io_bp_override = NULL;
+ BP_ZERO(bp);
+ ddt_exit(ddt);
+ return (ZIO_PIPELINE_CONTINUE);
+ }
+
+ dio = zio_write(zio, spa, txg, bp, zio->io_orig_data,
+ zio->io_orig_size, &czp, NULL,
+ zio_ddt_ditto_write_done, dde, zio->io_priority,
+ ZIO_DDT_CHILD_FLAGS(zio), &zio->io_bookmark);
+
+ zio_push_transform(dio, zio->io_data, zio->io_size, 0, NULL);
+ dde->dde_lead_zio[DDT_PHYS_DITTO] = dio;
+ }
+
+ if (ddp->ddp_phys_birth != 0 || dde->dde_lead_zio[p] != NULL) {
+ if (ddp->ddp_phys_birth != 0)
+ ddt_bp_fill(ddp, bp, txg);
+ if (dde->dde_lead_zio[p] != NULL)
+ zio_add_child(zio, dde->dde_lead_zio[p]);
+ else
+ ddt_phys_addref(ddp);
+ } else if (zio->io_bp_override) {
+ ASSERT(bp->blk_birth == txg);
+ ASSERT(BP_EQUAL(bp, zio->io_bp_override));
+ ddt_phys_fill(ddp, bp);
+ ddt_phys_addref(ddp);
+ } else {
+ cio = zio_write(zio, spa, txg, bp, zio->io_orig_data,
+ zio->io_orig_size, zp, zio_ddt_child_write_ready,
+ zio_ddt_child_write_done, dde, zio->io_priority,
+ ZIO_DDT_CHILD_FLAGS(zio), &zio->io_bookmark);
+
+ zio_push_transform(cio, zio->io_data, zio->io_size, 0, NULL);
+ dde->dde_lead_zio[p] = cio;
+ }
+
+ ddt_exit(ddt);
+
+ if (cio)
+ zio_nowait(cio);
+ if (dio)
+ zio_nowait(dio);
+
+ return (ZIO_PIPELINE_CONTINUE);
+}
+
+ddt_entry_t *freedde; /* for debugging */
+
+static int
+zio_ddt_free(zio_t *zio)
+{
+ spa_t *spa = zio->io_spa;
+ blkptr_t *bp = zio->io_bp;
+ ddt_t *ddt = ddt_select(spa, bp);
+ ddt_entry_t *dde;
+ ddt_phys_t *ddp;
+
+ ASSERT(BP_GET_DEDUP(bp));
+ ASSERT(zio->io_child_type == ZIO_CHILD_LOGICAL);
+
+ ddt_enter(ddt);
+ freedde = dde = ddt_lookup(ddt, bp, B_TRUE);
+ ddp = ddt_phys_select(dde, bp);
+ ddt_phys_decref(ddp);
+ ddt_exit(ddt);
+
+ 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_normal_class(spa);
+ blkptr_t *bp = zio->io_bp;
+ int error;
+
+ if (zio->io_gang_leader == NULL) {
+ ASSERT(zio->io_child_type > ZIO_CHILD_GANG);
+ zio->io_gang_leader = zio;
+ }
+
+ ASSERT(BP_IS_HOLE(bp));
+ ASSERT3U(BP_GET_NDVAS(bp), ==, 0);
+ ASSERT3U(zio->io_prop.zp_copies, >, 0);
+ ASSERT3U(zio->io_prop.zp_copies, <=, 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_copies, 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)
+{
+ ASSERT(bp->blk_birth == zio->io_txg || BP_IS_HOLE(bp));
+ ASSERT(zio->io_bp_override == NULL);
+
+ if (!BP_IS_HOLE(bp))
+ metaslab_free(zio->io_spa, bp, bp->blk_birth, B_TRUE);
+
+ 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_zil(spa_t *spa, uint64_t txg, blkptr_t *new_bp, blkptr_t *old_bp,
+ uint64_t size, boolean_t use_slog)
+{
+ int error = 1;
+
+ ASSERT(txg > spa_syncing_txg(spa));
+
+ if (use_slog)
+ error = metaslab_alloc(spa, spa_log_class(spa), size,
+ new_bp, 1, txg, old_bp, METASLAB_HINTBP_AVOID);
+
+ if (error)
+ error = metaslab_alloc(spa, spa_normal_class(spa), 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,
+ spa_version(spa) >= SPA_VERSION_SLIM_ZIL
+ ? ZIO_CHECKSUM_ZILOG2 : ZIO_CHECKSUM_ZILOG);
+ BP_SET_TYPE(new_bp, DMU_OT_INTENT_LOG);
+ BP_SET_LEVEL(new_bp, 0);
+ BP_SET_DEDUP(new_bp, 0);
+ BP_SET_BYTEORDER(new_bp, ZFS_HOST_BYTEORDER);
+ }
+
+ return (error);
+}
+
+/*
+ * Free an intent log block.
+ */
+void
+zio_free_zil(spa_t *spa, uint64_t txg, blkptr_t *bp)
+{
+ ASSERT(BP_GET_TYPE(bp) == DMU_OT_INTENT_LOG);
+ ASSERT(!BP_IS_GANG(bp));
+
+ zio_free(spa, txg, bp);
+}
+
+/*
+ * ==========================================================================
+ * Read and write to physical devices
+ * ==========================================================================
+ */
+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));
+ }
+
+ /*
+ * We keep track of time-sensitive I/Os so that the scan thread
+ * can quickly react to certain workloads. In particular, we care
+ * about non-scrubbing, top-level reads and writes with the following
+ * characteristics:
+ * - synchronous writes of user data to non-slog devices
+ * - any reads of user data
+ * When these conditions are met, adjust the timestamp of spa_last_io
+ * which allows the scan thread to adjust its workload accordingly.
+ */
+ if (!(zio->io_flags & ZIO_FLAG_SCAN_THREAD) && zio->io_bp != NULL &&
+ vd == vd->vdev_top && !vd->vdev_islog &&
+ zio->io_bookmark.zb_objset != DMU_META_OBJSET &&
+ zio->io_txg != spa_syncing_txg(spa)) {
+ uint64_t old = spa->spa_last_io;
+ uint64_t new = ddi_get_lbolt64();
+ if (old != new)
+ (void) atomic_cas_64(&spa->spa_last_io, old, new);
+ }
+
+ 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);
+ VERIFY(zio->io_type != ZIO_TYPE_WRITE || spa_writeable(spa));
+
+ /*
+ * If this is a repair I/O, and there's no self-healing involved --
+ * that is, we're just resilvering what we expect to resilver --
+ * then don't do the I/O unless zio's txg is actually in vd's DTL.
+ * This prevents spurious resilvering with nested replication.
+ * For example, given a mirror of mirrors, (A+B)+(C+D), if only
+ * A is out of date, we'll read from C+D, then use the data to
+ * resilver A+B -- but we don't actually want to resilver B, just A.
+ * The top-level mirror has no way to know this, so instead we just
+ * discard unnecessary repairs as we work our way down the vdev tree.
+ * The same logic applies to any form of nested replication:
+ * ditto + mirror, RAID-Z + replacing, etc. This covers them all.
+ */
+ if ((zio->io_flags & ZIO_FLAG_IO_REPAIR) &&
+ !(zio->io_flags & ZIO_FLAG_SELF_HEAL) &&
+ zio->io_txg != 0 && /* not a delegated i/o */
+ !vdev_dtl_contains(vd, DTL_PARTIAL, zio->io_txg, 1)) {
+ ASSERT(zio->io_type == ZIO_TYPE_WRITE);
+ zio_vdev_io_bypass(zio);
+ return (ZIO_PIPELINE_CONTINUE);
+ }
+
+ 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_CONTINUE);
+
+ 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,
+ zio, 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)
+ VERIFY(vdev_probe(vd, zio) == NULL);
+
+ return (ZIO_PIPELINE_CONTINUE);
+}
+
+/*
+ * For non-raidz ZIOs, we can just copy aside the bad data read from the
+ * disk, and use that to finish the checksum ereport later.
+ */
+static void
+zio_vsd_default_cksum_finish(zio_cksum_report_t *zcr,
+ const void *good_buf)
+{
+ /* no processing needed */
+ zfs_ereport_finish_checksum(zcr, good_buf, zcr->zcr_cbdata, B_FALSE);
+}
+
+/*ARGSUSED*/
+void
+zio_vsd_default_cksum_report(zio_t *zio, zio_cksum_report_t *zcr, void *ignored)
+{
+ void *buf = zio_buf_alloc(zio->io_size);
+
+ bcopy(zio->io_data, buf, zio->io_size);
+
+ zcr->zcr_cbinfo = zio->io_size;
+ zcr->zcr_cbdata = buf;
+ zcr->zcr_finish = zio_vsd_default_cksum_finish;
+ zcr->zcr_free = zio_buf_free;
+}
+
+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_ops->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.
+ *
+ * On retry, we cut in line in the issue queue, since we don't want
+ * compression/checksumming/etc. work to prevent our (cheap) IO reissue.
+ */
+ 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,
+ zio_requeue_io_start_cut_in_line);
+ 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 >>= 1;
+}
+
+void
+zio_vdev_io_redone(zio_t *zio)
+{
+ ASSERT(zio->io_stage == ZIO_STAGE_VDEV_IO_DONE);
+
+ zio->io_stage >>= 1;
+}
+
+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)
+{
+ zio_bad_cksum_t info;
+ blkptr_t *bp = zio->io_bp;
+ int error;
+
+ ASSERT(zio->io_vd != NULL);
+
+ 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, &info)) != 0) {
+ zio->io_error = error;
+ if (!(zio->io_flags & ZIO_FLAG_SPECULATIVE)) {
+ zfs_ereport_start_checksum(zio->io_spa,
+ zio->io_vd, zio, zio->io_offset,
+ zio->io_size, NULL, &info);
+ }
+ }
+
+ 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 &= ~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, *pio_next;
+
+ if (zio_wait_for_children(zio, ZIO_CHILD_GANG, ZIO_WAIT_READY) ||
+ zio_wait_for_children(zio, ZIO_CHILD_DDT, ZIO_WAIT_READY))
+ return (ZIO_PIPELINE_STOP);
+
+ if (zio->io_ready) {
+ 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;
+
+ mutex_enter(&zio->io_lock);
+ zio->io_state[ZIO_WAIT_READY] = 1;
+ pio = zio_walk_parents(zio);
+ mutex_exit(&zio->io_lock);
+
+ /*
+ * As we notify zio's parents, new parents could be added.
+ * New parents go to the head of zio's io_parent_list, however,
+ * so we will (correctly) not notify them. The remainder of zio's
+ * io_parent_list, from 'pio_next' onward, cannot change because
+ * all parents must wait for us to be done before they can be done.
+ */
+ for (; pio != NULL; pio = pio_next) {
+ pio_next = zio_walk_parents(zio);
+ zio_notify_parent(pio, zio, ZIO_WAIT_READY);
+ }
+
+ if (zio->io_flags & ZIO_FLAG_NODATA) {
+ if (BP_IS_GANG(bp)) {
+ zio->io_flags &= ~ZIO_FLAG_NODATA;
+ } else {
+ ASSERT((uintptr_t)zio->io_data < SPA_MAXBLOCKSIZE);
+ zio->io_pipeline &= ~ZIO_VDEV_IO_STAGES;
+ }
+ }
+
+ if (zio_injection_enabled &&
+ zio->io_spa->spa_syncing_txg == zio->io_txg)
+ zio_handle_ignored_writes(zio);
+
+ return (ZIO_PIPELINE_CONTINUE);
+}
+
+static int
+zio_done(zio_t *zio)
+{
+ spa_t *spa = zio->io_spa;
+ zio_t *lio = zio->io_logical;
+ blkptr_t *bp = zio->io_bp;
+ vdev_t *vd = zio->io_vd;
+ uint64_t psize = zio->io_size;
+ zio_t *pio, *pio_next;
+
+ /*
+ * If our 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_DDT, 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(bcmp(bp, &zio->io_bp_copy, sizeof (blkptr_t)) == 0 ||
+ (bp == zio_unique_parent(zio)->io_bp));
+ if (zio->io_type == ZIO_TYPE_WRITE && !BP_IS_HOLE(bp) &&
+ zio->io_bp_override == NULL &&
+ !(zio->io_flags & ZIO_FLAG_IO_REPAIR)) {
+ ASSERT(!BP_SHOULD_BYTESWAP(bp));
+ ASSERT3U(zio->io_prop.zp_copies, <=, BP_GET_NDVAS(bp));
+ ASSERT(BP_COUNT_GANG(bp) == 0 ||
+ (BP_COUNT_GANG(bp) == BP_GET_NDVAS(bp)));
+ }
+ }
+
+ /*
+ * If there were child vdev/gang/ddt errors, they apply to us now.
+ */
+ zio_inherit_child_errors(zio, ZIO_CHILD_VDEV);
+ zio_inherit_child_errors(zio, ZIO_CHILD_GANG);
+ zio_inherit_child_errors(zio, ZIO_CHILD_DDT);
+
+ /*
+ * If the I/O on the transformed data was successful, generate any
+ * checksum reports now while we still have the transformed data.
+ */
+ if (zio->io_error == 0) {
+ while (zio->io_cksum_report != NULL) {
+ zio_cksum_report_t *zcr = zio->io_cksum_report;
+ uint64_t align = zcr->zcr_align;
+ uint64_t asize = P2ROUNDUP(psize, align);
+ char *abuf = zio->io_data;
+
+ if (asize != psize) {
+ abuf = zio_buf_alloc(asize);
+ bcopy(zio->io_data, abuf, psize);
+ bzero(abuf + psize, asize - psize);
+ }
+
+ zio->io_cksum_report = zcr->zcr_next;
+ zcr->zcr_next = NULL;
+ zcr->zcr_finish(zcr, abuf);
+ zfs_ereport_free_checksum(zcr);
+
+ if (asize != psize)
+ zio_buf_free(abuf, asize);
+ }
+ }
+
+ 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_FLAG_DONT_PROPAGATE))) &&
+ 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);
+ ASSERT(zio->io_child_type == ZIO_CHILD_LOGICAL);
+
+ if (IO_IS_ALLOCATING(zio) &&
+ !(zio->io_flags & ZIO_FLAG_CANFAIL)) {
+ 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_flags & ZIO_FLAG_SCAN_THREAD) &&
+ zio->io_error == ENXIO &&
+ spa_load_state(spa) == SPA_LOAD_NONE &&
+ 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;
+
+ /*
+ * Here is a possibly good place to attempt to do
+ * either combinatorial reconstruction or error correction
+ * based on checksums. It also might be a good place
+ * to send out preliminary ereports before we suspend
+ * processing.
+ */
+ }
+
+ /*
+ * 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_error || zio->io_reexecute) &&
+ IO_IS_ALLOCATING(zio) && zio->io_gang_leader == zio &&
+ !(zio->io_flags & ZIO_FLAG_IO_REWRITE))
+ zio_dva_unallocate(zio, zio->io_gang_tree, bp);
+
+ zio_gang_tree_free(&zio->io_gang_tree);
+
+ /*
+ * Godfather I/Os should never suspend.
+ */
+ if ((zio->io_flags & ZIO_FLAG_GODFATHER) &&
+ (zio->io_reexecute & ZIO_REEXECUTE_SUSPEND))
+ zio->io_reexecute = 0;
+
+ 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);
+
+ zio->io_gang_leader = NULL;
+
+ mutex_enter(&zio->io_lock);
+ zio->io_state[ZIO_WAIT_DONE] = 1;
+ mutex_exit(&zio->io_lock);
+
+ /*
+ * "The Godfather" I/O monitors its children but is
+ * not a true parent to them. It will track them through
+ * the pipeline but severs its ties whenever they get into
+ * trouble (e.g. suspended). This allows "The Godfather"
+ * I/O to return status without blocking.
+ */
+ for (pio = zio_walk_parents(zio); pio != NULL; pio = pio_next) {
+ zio_link_t *zl = zio->io_walk_link;
+ pio_next = zio_walk_parents(zio);
+
+ if ((pio->io_flags & ZIO_FLAG_GODFATHER) &&
+ (zio->io_reexecute & ZIO_REEXECUTE_SUSPEND)) {
+ zio_remove_child(pio, zio, zl);
+ zio_notify_parent(pio, zio, ZIO_WAIT_DONE);
+ }
+ }
+
+ if ((pio = zio_unique_parent(zio)) != 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.
+ */
+ ASSERT(!(zio->io_flags & ZIO_FLAG_GODFATHER));
+ 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_count == 0);
+ ASSERT(zio->io_reexecute == 0);
+ ASSERT(zio->io_error == 0 || (zio->io_flags & ZIO_FLAG_CANFAIL));
+
+ /*
+ * Report any checksum errors, since the I/O is complete.
+ */
+ while (zio->io_cksum_report != NULL) {
+ zio_cksum_report_t *zcr = zio->io_cksum_report;
+ zio->io_cksum_report = zcr->zcr_next;
+ zcr->zcr_next = NULL;
+ zcr->zcr_finish(zcr, NULL);
+ zfs_ereport_free_checksum(zcr);
+ }
+
+ /*
+ * It is the responsibility of the done callback to ensure that this
+ * particular zio is no longer discoverable for adoption, and as
+ * such, cannot acquire any new parents.
+ */
+ if (zio->io_done)
+ zio->io_done(zio);
+
+ mutex_enter(&zio->io_lock);
+ zio->io_state[ZIO_WAIT_DONE] = 1;
+ mutex_exit(&zio->io_lock);
+
+ for (pio = zio_walk_parents(zio); pio != NULL; pio = pio_next) {
+ zio_link_t *zl = zio->io_walk_link;
+ pio_next = zio_walk_parents(zio);
+ zio_remove_child(pio, zio, zl);
+ 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[] = {
+ NULL,
+ zio_read_bp_init,
+ zio_free_bp_init,
+ zio_issue_async,
+ zio_write_bp_init,
+ zio_checksum_generate,
+ zio_ddt_read_start,
+ zio_ddt_read_done,
+ zio_ddt_write,
+ zio_ddt_free,
+ 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
+};