--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/usr/src/uts/common/fs/zfs/zio.c Mon Oct 31 11:33:35 2005 -0800
@@ -0,0 +1,1698 @@
+/*
+ * CDDL HEADER START
+ *
+ * The contents of this file are subject to the terms of the
+ * Common Development and Distribution License, Version 1.0 only
+ * (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 2005 Sun Microsystems, Inc. All rights reserved.
+ * Use is subject to license terms.
+ */
+
+#pragma ident "%Z%%M% %I% %E% SMI"
+
+#include <sys/zfs_context.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>
+
+static void zio_vdev_io_enter(zio_t *zio);
+static void zio_vdev_io_exit(zio_t *zio);
+
+/*
+ * ==========================================================================
+ * 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" };
+
+/* At or above this size, force gang blocking - for testing */
+uint64_t zio_gang_bang = SPA_MAXBLOCKSIZE + 1;
+
+typedef struct zio_sync_pass {
+ int zp_defer_free; /* defer frees after this pass */
+ int zp_dontcompress; /* don't compress after this pass */
+ int zp_rewrite; /* rewrite new bps after this pass */
+} zio_sync_pass_t;
+
+zio_sync_pass_t zio_sync_pass = {
+ 1, /* zp_defer_free */
+ 4, /* zp_dontcompress */
+ 1, /* zp_rewrite */
+};
+
+/*
+ * ==========================================================================
+ * I/O kmem caches
+ * ==========================================================================
+ */
+kmem_cache_t *zio_buf_cache[SPA_MAXBLOCKSIZE >> SPA_MINBLOCKSHIFT];
+
+void
+zio_init(void)
+{
+ size_t c;
+
+ /*
+ * 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[30];
+ (void) sprintf(name, "zio_buf_%lu", size);
+ zio_buf_cache[c] = kmem_cache_create(name, size,
+ align, NULL, NULL, NULL, NULL, NULL, 0);
+ dprintf("creating cache for size %5lx align %5lx\n",
+ size, align);
+ }
+ }
+
+ 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];
+ }
+}
+
+void
+zio_fini(void)
+{
+ size_t c;
+ kmem_cache_t *last_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;
+ }
+}
+
+/*
+ * ==========================================================================
+ * Allocate and free I/O buffers
+ * ==========================================================================
+ */
+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_SLEEP));
+}
+
+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);
+}
+
+/*
+ * ==========================================================================
+ * 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_t *zt = kmem_alloc(sizeof (zio_transform_t), KM_SLEEP);
+
+ zt->zt_data = data;
+ zt->zt_size = size;
+ zt->zt_bufsize = bufsize;
+
+ zt->zt_next = zio->io_transform_stack;
+ zio->io_transform_stack = zt;
+
+ zio->io_data = data;
+ zio->io_size = size;
+}
+
+static void
+zio_pop_transform(zio_t *zio, void **data, uint64_t *size, uint64_t *bufsize)
+{
+ zio_transform_t *zt = zio->io_transform_stack;
+
+ *data = zt->zt_data;
+ *size = zt->zt_size;
+ *bufsize = zt->zt_bufsize;
+
+ zio->io_transform_stack = zt->zt_next;
+ kmem_free(zt, sizeof (zio_transform_t));
+
+ if ((zt = zio->io_transform_stack) != NULL) {
+ zio->io_data = zt->zt_data;
+ zio->io_size = zt->zt_size;
+ }
+}
+
+static void
+zio_clear_transform_stack(zio_t *zio)
+{
+ void *data;
+ uint64_t size, bufsize;
+
+ ASSERT(zio->io_transform_stack != NULL);
+
+ zio_pop_transform(zio, &data, &size, &bufsize);
+ while (zio->io_transform_stack != NULL) {
+ zio_buf_free(data, bufsize);
+ zio_pop_transform(zio, &data, &size, &bufsize);
+ }
+}
+
+/*
+ * ==========================================================================
+ * Create the various types of I/O (read, write, free)
+ * ==========================================================================
+ */
+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, uint8_t stage, uint32_t pipeline)
+{
+ zio_t *zio;
+
+ ASSERT3U(size, <=, SPA_MAXBLOCKSIZE);
+ ASSERT(P2PHASE(size, SPA_MINBLOCKSIZE) == 0);
+
+ zio = kmem_zalloc(sizeof (zio_t), KM_SLEEP);
+ zio->io_parent = pio;
+ zio->io_spa = spa;
+ zio->io_txg = txg;
+ if (bp != NULL) {
+ zio->io_bp = bp;
+ zio->io_bp_copy = *bp;
+ zio->io_bp_orig = *bp;
+ /* XXBP - Need to inherit this when it matters */
+ zio->io_dva_index = 0;
+ }
+ zio->io_done = done;
+ zio->io_private = private;
+ zio->io_type = type;
+ zio->io_priority = priority;
+ zio->io_stage = stage;
+ zio->io_pipeline = pipeline;
+ zio->io_async_stages = ZIO_ASYNC_PIPELINE_STAGES;
+ zio->io_timestamp = lbolt64;
+ zio->io_flags = flags;
+ zio_push_transform(zio, data, size, size);
+
+ if (pio == NULL) {
+ if (!(flags & ZIO_FLAG_CONFIG_HELD))
+ spa_config_enter(zio->io_spa, RW_READER);
+ zio->io_root = zio;
+ } else {
+ zio->io_root = pio->io_root;
+
+ mutex_enter(&pio->io_lock);
+ if (stage < ZIO_STAGE_READY)
+ pio->io_children_notready++;
+ pio->io_children_notdone++;
+ zio->io_sibling_next = pio->io_child;
+ zio->io_sibling_prev = NULL;
+ if (pio->io_child != NULL)
+ pio->io_child->io_sibling_prev = zio;
+ pio->io_child = zio;
+ mutex_exit(&pio->io_lock);
+ }
+
+ return (zio);
+}
+
+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, ZIO_STAGE_OPEN,
+ ZIO_WAIT_FOR_CHILDREN_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, blkptr_t *bp, void *data,
+ uint64_t size, zio_done_func_t *done, void *private,
+ int priority, int flags)
+{
+ zio_t *zio;
+ dva_t *dva;
+
+ ASSERT3U(size, ==, BP_GET_LSIZE(bp));
+
+ zio = zio_create(pio, spa, bp->blk_birth, bp, data, size, done, private,
+ ZIO_TYPE_READ, priority, flags, ZIO_STAGE_OPEN, ZIO_READ_PIPELINE);
+
+ /*
+ * Work off our copy of the bp so the caller can free it.
+ */
+ zio->io_bp = &zio->io_bp_copy;
+
+ bp = zio->io_bp;
+ dva = ZIO_GET_DVA(zio);
+
+ if (BP_GET_COMPRESS(bp) != ZIO_COMPRESS_OFF) {
+ uint64_t csize = BP_GET_PSIZE(bp);
+ void *cbuf = zio_buf_alloc(csize);
+
+ zio_push_transform(zio, cbuf, csize, csize);
+ zio->io_pipeline |= 1U << ZIO_STAGE_READ_DECOMPRESS;
+ }
+
+ if (DVA_GET_GANG(dva)) {
+ uint64_t gsize = SPA_GANGBLOCKSIZE;
+ void *gbuf = zio_buf_alloc(gsize);
+
+ zio_push_transform(zio, gbuf, gsize, gsize);
+ zio->io_pipeline |= 1U << ZIO_STAGE_READ_GANG_MEMBERS;
+ }
+
+ return (zio);
+}
+
+zio_t *
+zio_write(zio_t *pio, spa_t *spa, int checksum, int compress,
+ uint64_t txg, blkptr_t *bp, void *data, uint64_t size,
+ zio_done_func_t *done, void *private, int priority, int flags)
+{
+ zio_t *zio;
+
+ ASSERT(checksum >= ZIO_CHECKSUM_OFF &&
+ checksum < ZIO_CHECKSUM_FUNCTIONS);
+
+ ASSERT(compress >= ZIO_COMPRESS_OFF &&
+ compress < ZIO_COMPRESS_FUNCTIONS);
+
+ zio = zio_create(pio, spa, txg, bp, data, size, done, private,
+ ZIO_TYPE_WRITE, priority, flags,
+ ZIO_STAGE_OPEN, ZIO_WRITE_PIPELINE);
+
+ zio->io_checksum = checksum;
+ zio->io_compress = compress;
+
+ if (compress != ZIO_COMPRESS_OFF)
+ zio->io_async_stages |= 1U << ZIO_STAGE_WRITE_COMPRESS;
+
+ if (bp->blk_birth != txg) {
+ /* XXX the bp usually (always?) gets re-zeroed later */
+ BP_ZERO(bp);
+ BP_SET_LSIZE(bp, size);
+ BP_SET_PSIZE(bp, size);
+ }
+
+ return (zio);
+}
+
+zio_t *
+zio_rewrite(zio_t *pio, spa_t *spa, int checksum,
+ uint64_t txg, blkptr_t *bp, void *data, uint64_t size,
+ zio_done_func_t *done, void *private, int priority, int flags)
+{
+ zio_t *zio;
+
+ /* XXBP - We need to re-evaluate when to insert pipeline stages */
+ zio = zio_create(pio, spa, txg, bp, data, size, done, private,
+ ZIO_TYPE_WRITE, priority, flags,
+ ZIO_STAGE_OPEN, ZIO_REWRITE_PIPELINE);
+
+ zio->io_checksum = checksum;
+ zio->io_compress = ZIO_COMPRESS_OFF;
+
+ return (zio);
+}
+
+static zio_t *
+zio_write_allocate(zio_t *pio, spa_t *spa, int checksum,
+ uint64_t txg, blkptr_t *bp, void *data, uint64_t size,
+ zio_done_func_t *done, void *private, int priority, int flags)
+{
+ zio_t *zio;
+
+ BP_ZERO(bp);
+ BP_SET_LSIZE(bp, size);
+ BP_SET_PSIZE(bp, size);
+ BP_SET_COMPRESS(bp, ZIO_COMPRESS_OFF);
+
+ zio = zio_create(pio, spa, txg, bp, data, size, done, private,
+ ZIO_TYPE_WRITE, priority, flags,
+ ZIO_STAGE_OPEN, ZIO_WRITE_ALLOCATE_PIPELINE);
+
+ zio->io_checksum = checksum;
+ zio->io_compress = ZIO_COMPRESS_OFF;
+
+ 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)
+{
+ zio_t *zio;
+
+ ASSERT(!BP_IS_HOLE(bp));
+
+ if (txg == spa->spa_syncing_txg &&
+ spa->spa_sync_pass > zio_sync_pass.zp_defer_free) {
+ bplist_enqueue_deferred(&spa->spa_sync_bplist, bp);
+ return (zio_null(pio, spa, NULL, NULL, 0));
+ }
+
+ /* XXBP - We need to re-evaluate when to insert pipeline stages */
+ zio = zio_create(pio, spa, txg, bp, NULL, 0, done, private,
+ ZIO_TYPE_FREE, ZIO_PRIORITY_FREE, 0,
+ ZIO_STAGE_OPEN, ZIO_FREE_PIPELINE);
+
+ zio->io_bp = &zio->io_bp_copy;
+
+ 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)
+{
+ 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);
+
+ /* XXBP - We need to re-evaluate when to insert pipeline stages */
+ zio = zio_create(pio, spa, txg, bp, NULL, 0, done, private,
+ ZIO_TYPE_CLAIM, ZIO_PRIORITY_NOW, 0,
+ ZIO_STAGE_OPEN, ZIO_CLAIM_PIPELINE);
+
+ zio->io_bp = &zio->io_bp_copy;
+
+ 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,
+ ZIO_STAGE_OPEN, ZIO_IOCTL_PIPELINE);
+
+ zio->io_vd = vd;
+ 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);
+}
+
+static void
+zio_phys_bp_init(vdev_t *vd, blkptr_t *bp, uint64_t offset, uint64_t size,
+ int checksum)
+{
+ ASSERT(vd->vdev_children == 0);
+
+ ASSERT(size <= SPA_MAXBLOCKSIZE);
+ ASSERT(P2PHASE(size, SPA_MINBLOCKSIZE) == 0);
+ ASSERT(P2PHASE(offset, SPA_MINBLOCKSIZE) == 0);
+
+ ASSERT(offset + size <= VDEV_LABEL_START_SIZE ||
+ offset >= vd->vdev_psize - VDEV_LABEL_END_SIZE);
+ ASSERT3U(offset + size, <=, vd->vdev_psize);
+
+ BP_ZERO(bp);
+
+ BP_SET_LSIZE(bp, size);
+ BP_SET_PSIZE(bp, size);
+
+ BP_SET_CHECKSUM(bp, checksum);
+ BP_SET_COMPRESS(bp, ZIO_COMPRESS_OFF);
+ BP_SET_BYTEORDER(bp, ZFS_HOST_BYTEORDER);
+
+ if (checksum != ZIO_CHECKSUM_OFF)
+ ZIO_SET_CHECKSUM(&bp->blk_cksum, offset, 0, 0, 0);
+}
+
+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)
+{
+ zio_t *zio;
+ blkptr_t blk;
+
+ zio_phys_bp_init(vd, &blk, offset, size, checksum);
+
+ zio = zio_create(pio, vd->vdev_spa, 0, &blk, data, size, done, private,
+ ZIO_TYPE_READ, priority, flags | ZIO_FLAG_PHYSICAL,
+ ZIO_STAGE_OPEN, ZIO_READ_PHYS_PIPELINE);
+
+ zio->io_vd = vd;
+ zio->io_offset = offset;
+
+ /*
+ * Work off our copy of the bp so the caller can free it.
+ */
+ zio->io_bp = &zio->io_bp_copy;
+
+ 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)
+{
+ zio_block_tail_t *zbt;
+ void *wbuf;
+ zio_t *zio;
+ blkptr_t blk;
+
+ zio_phys_bp_init(vd, &blk, offset, size, checksum);
+
+ zio = zio_create(pio, vd->vdev_spa, 0, &blk, data, size, done, private,
+ ZIO_TYPE_WRITE, priority, flags | ZIO_FLAG_PHYSICAL,
+ ZIO_STAGE_OPEN, ZIO_WRITE_PHYS_PIPELINE);
+
+ zio->io_vd = vd;
+ zio->io_offset = offset;
+
+ zio->io_bp = &zio->io_bp_copy;
+ zio->io_checksum = checksum;
+
+ if (zio_checksum_table[checksum].ci_zbt) {
+ /*
+ * zbt checksums are necessarily destructive -- they modify
+ * one word 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.
+ */
+ wbuf = zio_buf_alloc(size);
+ bcopy(data, wbuf, size);
+ zio_push_transform(zio, wbuf, size, size);
+
+ zbt = (zio_block_tail_t *)((char *)wbuf + size) - 1;
+ zbt->zbt_cksum = blk.blk_cksum;
+ }
+
+ return (zio);
+}
+
+/*
+ * Create a child I/O to do some work for us. It has no associated bp.
+ */
+zio_t *
+zio_vdev_child_io(zio_t *zio, 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 *cio;
+
+ 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;
+ zio->io_pipeline &= ~(1U << ZIO_STAGE_CHECKSUM_VERIFY);
+ }
+
+ cio = zio_create(zio, zio->io_spa, zio->io_txg, bp, data, size,
+ done, private, type, priority,
+ (zio->io_flags & ZIO_FLAG_VDEV_INHERIT) | ZIO_FLAG_CANFAIL | flags,
+ ZIO_STAGE_VDEV_IO_SETUP - 1, pipeline);
+
+ cio->io_vd = vd;
+ cio->io_offset = offset;
+
+ return (cio);
+}
+
+/*
+ * ==========================================================================
+ * Initiate I/O, either sync or async
+ * ==========================================================================
+ */
+int
+zio_wait(zio_t *zio)
+{
+ int error;
+
+ ASSERT(zio->io_stage == ZIO_STAGE_OPEN);
+
+ zio->io_waiter = curthread;
+
+ zio_next_stage_async(zio);
+
+ mutex_enter(&zio->io_lock);
+ while (zio->io_stalled != ZIO_STAGE_DONE)
+ cv_wait(&zio->io_cv, &zio->io_lock);
+ mutex_exit(&zio->io_lock);
+
+ error = zio->io_error;
+
+ kmem_free(zio, sizeof (zio_t));
+
+ return (error);
+}
+
+void
+zio_nowait(zio_t *zio)
+{
+ zio_next_stage_async(zio);
+}
+
+/*
+ * ==========================================================================
+ * I/O pipeline interlocks: parent/child dependency scoreboarding
+ * ==========================================================================
+ */
+static void
+zio_wait_for_children(zio_t *zio, uint32_t stage, uint64_t *countp)
+{
+ mutex_enter(&zio->io_lock);
+ if (*countp == 0) {
+ ASSERT(zio->io_stalled == 0);
+ mutex_exit(&zio->io_lock);
+ zio_next_stage(zio);
+ } else {
+ if (zio->io_stage == ZIO_STAGE_VDEV_IO_START)
+ zio_vdev_io_exit(zio);
+ zio->io_stalled = stage;
+ mutex_exit(&zio->io_lock);
+ }
+}
+
+static void
+zio_notify_parent(zio_t *zio, uint32_t stage, uint64_t *countp)
+{
+ zio_t *pio = zio->io_parent;
+
+ mutex_enter(&pio->io_lock);
+ if (pio->io_error == 0 && !(zio->io_flags & ZIO_FLAG_DONT_PROPAGATE))
+ pio->io_error = zio->io_error;
+ if (--*countp == 0 && pio->io_stalled == stage) {
+ if (pio->io_stage == ZIO_STAGE_VDEV_IO_START)
+ zio_vdev_io_enter(pio);
+ pio->io_stalled = 0;
+ mutex_exit(&pio->io_lock);
+ zio_next_stage_async(pio);
+ } else {
+ mutex_exit(&pio->io_lock);
+ }
+}
+
+static void
+zio_wait_children_ready(zio_t *zio)
+{
+ zio_wait_for_children(zio, ZIO_STAGE_WAIT_CHILDREN_READY,
+ &zio->io_children_notready);
+}
+
+void
+zio_wait_children_done(zio_t *zio)
+{
+ zio_wait_for_children(zio, ZIO_STAGE_WAIT_CHILDREN_DONE,
+ &zio->io_children_notdone);
+}
+
+static void
+zio_ready(zio_t *zio)
+{
+ zio_t *pio = zio->io_parent;
+
+ if (pio != NULL)
+ zio_notify_parent(zio, ZIO_STAGE_WAIT_CHILDREN_READY,
+ &pio->io_children_notready);
+
+ if (zio->io_bp)
+ zio->io_bp_copy = *zio->io_bp;
+
+ zio_next_stage(zio);
+}
+
+static void
+zio_done(zio_t *zio)
+{
+ zio_t *pio = zio->io_parent;
+ spa_t *spa = zio->io_spa;
+ blkptr_t *bp = zio->io_bp;
+ vdev_t *vd = zio->io_vd;
+ char blkbuf[300];
+
+ ASSERT(zio->io_children_notready == 0);
+ ASSERT(zio->io_children_notdone == 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);
+ if (zio->io_type == ZIO_TYPE_WRITE && !BP_IS_HOLE(bp) &&
+ !(zio->io_flags & ZIO_FLAG_IO_REPAIR))
+ ASSERT(!BP_SHOULD_BYTESWAP(bp));
+ }
+
+ if (vd != NULL)
+ vdev_stat_update(zio);
+
+ if (zio->io_error) {
+ sprintf_blkptr(blkbuf, bp ? bp : &zio->io_bp_copy);
+ dprintf("ZFS: %s (%s on %s off %llx: zio %p %s): error %d\n",
+ zio->io_error == ECKSUM ? "bad checksum" : "I/O failure",
+ zio_type_name[zio->io_type],
+ vdev_description(vd),
+ (u_longlong_t)zio->io_offset,
+ zio, blkbuf, zio->io_error);
+ }
+
+ if (zio->io_numerrors != 0 && zio->io_type == ZIO_TYPE_WRITE) {
+ sprintf_blkptr(blkbuf, bp ? bp : &zio->io_bp_copy);
+ dprintf("ZFS: %s (%s on %s off %llx: zio %p %s): %d errors\n",
+ "partial write",
+ zio_type_name[zio->io_type],
+ vdev_description(vd),
+ (u_longlong_t)zio->io_offset,
+ zio, blkbuf, zio->io_numerrors);
+ }
+
+ if (zio->io_error && !(zio->io_flags & ZIO_FLAG_CANFAIL)) {
+ sprintf_blkptr(blkbuf, bp ? bp : &zio->io_bp_copy);
+ panic("ZFS: %s (%s on %s off %llx: zio %p %s): error %d",
+ zio->io_error == ECKSUM ? "bad checksum" : "I/O failure",
+ zio_type_name[zio->io_type],
+ vdev_description(vd),
+ (u_longlong_t)zio->io_offset,
+ zio, blkbuf, zio->io_error);
+ }
+
+ zio_clear_transform_stack(zio);
+
+ if (zio->io_done)
+ zio->io_done(zio);
+
+ ASSERT(zio->io_delegate_list == NULL);
+ ASSERT(zio->io_delegate_next == NULL);
+
+ if (pio != NULL) {
+ zio_t *next, *prev;
+
+ 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);
+
+ zio_notify_parent(zio, ZIO_STAGE_WAIT_CHILDREN_DONE,
+ &pio->io_children_notdone);
+ }
+
+ if (pio == NULL && !(zio->io_flags & ZIO_FLAG_CONFIG_HELD))
+ spa_config_exit(spa);
+
+ if (zio->io_waiter != NULL) {
+ mutex_enter(&zio->io_lock);
+ ASSERT(zio->io_stage == ZIO_STAGE_DONE);
+ zio->io_stalled = zio->io_stage;
+ cv_broadcast(&zio->io_cv);
+ mutex_exit(&zio->io_lock);
+ } else {
+ kmem_free(zio, sizeof (zio_t));
+ }
+}
+
+/*
+ * ==========================================================================
+ * Compression support
+ * ==========================================================================
+ */
+static void
+zio_write_compress(zio_t *zio)
+{
+ int compress = zio->io_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;
+
+ 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);
+ if (pass > zio_sync_pass.zp_dontcompress)
+ compress = ZIO_COMPRESS_OFF;
+ } else {
+ ASSERT(BP_IS_HOLE(bp));
+ pass = 1;
+ }
+
+ if (compress != ZIO_COMPRESS_OFF)
+ if (!zio_compress_data(compress, zio->io_data, zio->io_size,
+ &cbuf, &csize, &cbufsize))
+ compress = ZIO_COMPRESS_OFF;
+
+ if (compress != ZIO_COMPRESS_OFF && csize != 0)
+ zio_push_transform(zio, cbuf, csize, cbufsize);
+
+ /*
+ * 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 reallocate 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 > zio_sync_pass.zp_rewrite) {
+ ASSERT(csize != 0);
+ ASSERT3U(BP_GET_COMPRESS(bp), ==, compress);
+ ASSERT3U(BP_GET_LSIZE(bp), ==, lsize);
+
+ zio->io_pipeline = ZIO_REWRITE_PIPELINE;
+ } else {
+ if (bp->blk_birth == zio->io_txg) {
+ ASSERT3U(BP_GET_LSIZE(bp), ==, lsize);
+ bzero(bp, sizeof (blkptr_t));
+ }
+ if (csize == 0) {
+ BP_ZERO(bp);
+ zio->io_pipeline = ZIO_WAIT_FOR_CHILDREN_PIPELINE;
+ } else {
+ BP_SET_LSIZE(bp, lsize);
+ BP_SET_PSIZE(bp, csize);
+ BP_SET_COMPRESS(bp, compress);
+ zio->io_pipeline = ZIO_WRITE_ALLOCATE_PIPELINE;
+ }
+ }
+
+ zio_next_stage(zio);
+}
+
+static void
+zio_read_decompress(zio_t *zio)
+{
+ blkptr_t *bp = zio->io_bp;
+ void *data;
+ uint64_t size;
+ uint64_t bufsize;
+ int compress = BP_GET_COMPRESS(bp);
+
+ ASSERT(compress != ZIO_COMPRESS_OFF);
+
+ zio_pop_transform(zio, &data, &size, &bufsize);
+
+ if (zio_decompress_data(compress, data, size,
+ zio->io_data, zio->io_size))
+ zio->io_error = EIO;
+
+ zio_buf_free(data, bufsize);
+
+ zio_next_stage(zio);
+}
+
+/*
+ * ==========================================================================
+ * Gang block support
+ * ==========================================================================
+ */
+static void
+zio_gang_pipeline(zio_t *zio)
+{
+ /*
+ * By default, the pipeline assumes that we're dealing with a gang
+ * block. If we're not, strip out any gang-specific stages.
+ */
+ if (!DVA_GET_GANG(ZIO_GET_DVA(zio)))
+ zio->io_pipeline &= ~ZIO_GANG_STAGES;
+
+ zio_next_stage(zio);
+}
+
+static void
+zio_gang_byteswap(zio_t *zio)
+{
+ ASSERT(zio->io_size == SPA_GANGBLOCKSIZE);
+
+ if (BP_SHOULD_BYTESWAP(zio->io_bp))
+ byteswap_uint64_array(zio->io_data, zio->io_size);
+}
+
+static void
+zio_get_gang_header(zio_t *zio)
+{
+ blkptr_t *bp = zio->io_bp;
+ uint64_t gsize = SPA_GANGBLOCKSIZE;
+ void *gbuf = zio_buf_alloc(gsize);
+
+ ASSERT(DVA_GET_GANG(ZIO_GET_DVA(zio)));
+
+ zio_push_transform(zio, gbuf, gsize, gsize);
+
+ zio_nowait(zio_create(zio, zio->io_spa, bp->blk_birth, bp, gbuf, gsize,
+ NULL, NULL, ZIO_TYPE_READ, zio->io_priority,
+ zio->io_flags & ZIO_FLAG_GANG_INHERIT,
+ ZIO_STAGE_OPEN, ZIO_READ_PIPELINE));
+
+ zio_wait_children_done(zio);
+}
+
+static void
+zio_read_gang_members(zio_t *zio)
+{
+ zio_gbh_phys_t *gbh;
+ uint64_t gsize, gbufsize, loff, lsize;
+ int i;
+
+ ASSERT(DVA_GET_GANG(ZIO_GET_DVA(zio)));
+
+ zio_gang_byteswap(zio);
+ zio_pop_transform(zio, (void **)&gbh, &gsize, &gbufsize);
+
+ for (loff = 0, i = 0; loff != zio->io_size; loff += lsize, i++) {
+ blkptr_t *gbp = &gbh->zg_blkptr[i];
+ lsize = BP_GET_PSIZE(gbp);
+
+ ASSERT(BP_GET_COMPRESS(gbp) == ZIO_COMPRESS_OFF);
+ ASSERT3U(lsize, ==, BP_GET_LSIZE(gbp));
+ ASSERT3U(loff + lsize, <=, zio->io_size);
+ ASSERT(i < SPA_GBH_NBLKPTRS);
+ ASSERT(!BP_IS_HOLE(gbp));
+
+ zio_nowait(zio_read(zio, zio->io_spa, gbp,
+ (char *)zio->io_data + loff, lsize, NULL, NULL,
+ zio->io_priority, zio->io_flags & ZIO_FLAG_GANG_INHERIT));
+ }
+
+ zio_buf_free(gbh, gbufsize);
+ zio_wait_children_done(zio);
+}
+
+static void
+zio_rewrite_gang_members(zio_t *zio)
+{
+ zio_gbh_phys_t *gbh;
+ uint64_t gsize, gbufsize, loff, lsize;
+ int i;
+
+ ASSERT(DVA_GET_GANG(ZIO_GET_DVA(zio)));
+ ASSERT3U(zio->io_size, ==, SPA_GANGBLOCKSIZE);
+
+ zio_gang_byteswap(zio);
+ zio_pop_transform(zio, (void **)&gbh, &gsize, &gbufsize);
+
+ ASSERT(gsize == gbufsize);
+
+ for (loff = 0, i = 0; loff != zio->io_size; loff += lsize, i++) {
+ blkptr_t *gbp = &gbh->zg_blkptr[i];
+ lsize = BP_GET_PSIZE(gbp);
+
+ ASSERT(BP_GET_COMPRESS(gbp) == ZIO_COMPRESS_OFF);
+ ASSERT3U(lsize, ==, BP_GET_LSIZE(gbp));
+ ASSERT3U(loff + lsize, <=, zio->io_size);
+ ASSERT(i < SPA_GBH_NBLKPTRS);
+ ASSERT(!BP_IS_HOLE(gbp));
+
+ zio_nowait(zio_rewrite(zio, zio->io_spa, zio->io_checksum,
+ zio->io_txg, gbp, (char *)zio->io_data + loff, lsize,
+ NULL, NULL, zio->io_priority, zio->io_flags));
+ }
+
+ zio_push_transform(zio, gbh, gsize, gbufsize);
+ zio_wait_children_ready(zio);
+}
+
+static void
+zio_free_gang_members(zio_t *zio)
+{
+ zio_gbh_phys_t *gbh;
+ uint64_t gsize, gbufsize;
+ int i;
+
+ ASSERT(DVA_GET_GANG(ZIO_GET_DVA(zio)));
+
+ zio_gang_byteswap(zio);
+ zio_pop_transform(zio, (void **)&gbh, &gsize, &gbufsize);
+
+ for (i = 0; i < SPA_GBH_NBLKPTRS; i++) {
+ blkptr_t *gbp = &gbh->zg_blkptr[i];
+
+ if (BP_IS_HOLE(gbp))
+ continue;
+ zio_nowait(zio_free(zio, zio->io_spa, zio->io_txg,
+ gbp, NULL, NULL));
+ }
+
+ zio_buf_free(gbh, gbufsize);
+ zio_next_stage(zio);
+}
+
+static void
+zio_claim_gang_members(zio_t *zio)
+{
+ zio_gbh_phys_t *gbh;
+ uint64_t gsize, gbufsize;
+ int i;
+
+ ASSERT(DVA_GET_GANG(ZIO_GET_DVA(zio)));
+
+ zio_gang_byteswap(zio);
+ zio_pop_transform(zio, (void **)&gbh, &gsize, &gbufsize);
+
+ for (i = 0; i < SPA_GBH_NBLKPTRS; i++) {
+ blkptr_t *gbp = &gbh->zg_blkptr[i];
+ if (BP_IS_HOLE(gbp))
+ continue;
+ zio_nowait(zio_claim(zio, zio->io_spa, zio->io_txg,
+ gbp, NULL, NULL));
+ }
+
+ zio_buf_free(gbh, gbufsize);
+ zio_next_stage(zio);
+}
+
+static void
+zio_write_allocate_gang_member_done(zio_t *zio)
+{
+ zio_t *pio = zio->io_parent;
+ dva_t *cdva = ZIO_GET_DVA(zio);
+ dva_t *pdva = ZIO_GET_DVA(pio);
+ uint64_t asize;
+
+ ASSERT(DVA_GET_GANG(pdva));
+
+ /* XXBP - Need to be careful here with multiple DVAs */
+ mutex_enter(&pio->io_lock);
+ asize = DVA_GET_ASIZE(pdva);
+ asize += DVA_GET_ASIZE(cdva);
+ DVA_SET_ASIZE(pdva, asize);
+ mutex_exit(&pio->io_lock);
+}
+
+static void
+zio_write_allocate_gang_members(zio_t *zio)
+{
+ blkptr_t *bp = zio->io_bp;
+ dva_t *dva = ZIO_GET_DVA(zio);
+ zio_gbh_phys_t *gbh;
+ uint64_t resid = zio->io_size;
+ uint64_t maxalloc = P2ROUNDUP(zio->io_size >> 1, SPA_MINBLOCKSIZE);
+ uint64_t gsize, loff, lsize;
+ uint32_t gbps_left;
+ int error;
+ int i;
+
+ gsize = SPA_GANGBLOCKSIZE;
+ gbps_left = SPA_GBH_NBLKPTRS;
+
+ error = metaslab_alloc(zio->io_spa, gsize, dva, zio->io_txg);
+ if (error == ENOSPC)
+ panic("can't allocate gang block header");
+ ASSERT(error == 0);
+
+ DVA_SET_GANG(dva, 1);
+
+ bp->blk_birth = zio->io_txg;
+
+ gbh = zio_buf_alloc(gsize);
+ bzero(gbh, gsize);
+
+ for (loff = 0, i = 0; loff != zio->io_size;
+ loff += lsize, resid -= lsize, gbps_left--, i++) {
+ blkptr_t *gbp = &gbh->zg_blkptr[i];
+ dva = &gbp->blk_dva[0];
+
+ ASSERT(gbps_left != 0);
+ maxalloc = MIN(maxalloc, resid);
+
+ while (resid <= maxalloc * gbps_left) {
+ error = metaslab_alloc(zio->io_spa, maxalloc, dva,
+ zio->io_txg);
+ if (error == 0)
+ break;
+ ASSERT3U(error, ==, ENOSPC);
+ if (maxalloc == SPA_MINBLOCKSIZE)
+ panic("really out of space");
+ maxalloc = P2ROUNDUP(maxalloc >> 1, SPA_MINBLOCKSIZE);
+ }
+
+ if (resid <= maxalloc * gbps_left) {
+ lsize = maxalloc;
+ BP_SET_LSIZE(gbp, lsize);
+ BP_SET_PSIZE(gbp, lsize);
+ BP_SET_COMPRESS(gbp, ZIO_COMPRESS_OFF);
+ gbp->blk_birth = zio->io_txg;
+ zio_nowait(zio_rewrite(zio, zio->io_spa,
+ zio->io_checksum, zio->io_txg, gbp,
+ (char *)zio->io_data + loff, lsize,
+ zio_write_allocate_gang_member_done, NULL,
+ zio->io_priority, zio->io_flags));
+ } else {
+ lsize = P2ROUNDUP(resid / gbps_left, SPA_MINBLOCKSIZE);
+ ASSERT(lsize != SPA_MINBLOCKSIZE);
+ zio_nowait(zio_write_allocate(zio, zio->io_spa,
+ zio->io_checksum, zio->io_txg, gbp,
+ (char *)zio->io_data + loff, lsize,
+ zio_write_allocate_gang_member_done, NULL,
+ zio->io_priority, zio->io_flags));
+ }
+ }
+
+ ASSERT(resid == 0 && loff == zio->io_size);
+
+ zio->io_pipeline |= 1U << ZIO_STAGE_GANG_CHECKSUM_GENERATE;
+
+ zio_push_transform(zio, gbh, gsize, gsize);
+ zio_wait_children_done(zio);
+}
+
+/*
+ * ==========================================================================
+ * Allocate and free blocks
+ * ==========================================================================
+ */
+static void
+zio_dva_allocate(zio_t *zio)
+{
+ blkptr_t *bp = zio->io_bp;
+ dva_t *dva = ZIO_GET_DVA(zio);
+ int error;
+
+ ASSERT(BP_IS_HOLE(bp));
+
+ /* For testing, make some blocks above a certain size be gang blocks */
+ if (zio->io_size >= zio_gang_bang && (lbolt & 0x3) == 0) {
+ zio_write_allocate_gang_members(zio);
+ return;
+ }
+
+ ASSERT3U(zio->io_size, ==, BP_GET_PSIZE(bp));
+
+ error = metaslab_alloc(zio->io_spa, zio->io_size, dva, zio->io_txg);
+
+ if (error == 0) {
+ bp->blk_birth = zio->io_txg;
+ } else if (error == ENOSPC) {
+ if (zio->io_size == SPA_MINBLOCKSIZE)
+ panic("really, truly out of space");
+ zio_write_allocate_gang_members(zio);
+ return;
+ } else {
+ zio->io_error = error;
+ }
+ zio_next_stage(zio);
+}
+
+static void
+zio_dva_free(zio_t *zio)
+{
+ blkptr_t *bp = zio->io_bp;
+ dva_t *dva = ZIO_GET_DVA(zio);
+
+ ASSERT(!BP_IS_HOLE(bp));
+
+ metaslab_free(zio->io_spa, dva, zio->io_txg);
+
+ BP_ZERO(bp);
+
+ zio_next_stage(zio);
+}
+
+static void
+zio_dva_claim(zio_t *zio)
+{
+ blkptr_t *bp = zio->io_bp;
+ dva_t *dva = ZIO_GET_DVA(zio);
+
+ ASSERT(!BP_IS_HOLE(bp));
+
+ zio->io_error = metaslab_claim(zio->io_spa, dva, zio->io_txg);
+
+ zio_next_stage(zio);
+}
+
+static void
+zio_dva_translate(zio_t *zio)
+{
+ spa_t *spa = zio->io_spa;
+ dva_t *dva = ZIO_GET_DVA(zio);
+ uint64_t vdev = DVA_GET_VDEV(dva);
+ uint64_t offset = DVA_GET_OFFSET(dva);
+
+ ASSERT3U(zio->io_size, ==, ZIO_GET_IOSIZE(zio));
+
+ zio->io_offset = offset;
+
+ if ((zio->io_vd = vdev_lookup_top(spa, vdev)) == NULL)
+ zio->io_error = ENXIO;
+ else if (offset + zio->io_size > zio->io_vd->vdev_asize)
+ zio->io_error = EOVERFLOW;
+
+ zio_next_stage(zio);
+}
+
+/*
+ * ==========================================================================
+ * Read and write to physical devices
+ * ==========================================================================
+ */
+static void
+zio_vdev_io_enter(zio_t *zio)
+{
+ vdev_t *tvd = zio->io_vd->vdev_top;
+
+ mutex_enter(&tvd->vdev_io_lock);
+ ASSERT(zio->io_pending.list_next == NULL);
+ list_insert_tail(&tvd->vdev_io_pending, zio);
+ mutex_exit(&tvd->vdev_io_lock);
+}
+
+static void
+zio_vdev_io_exit(zio_t *zio)
+{
+ vdev_t *tvd = zio->io_vd->vdev_top;
+
+ mutex_enter(&tvd->vdev_io_lock);
+ ASSERT(zio->io_pending.list_next != NULL);
+ list_remove(&tvd->vdev_io_pending, zio);
+ if (list_head(&tvd->vdev_io_pending) == NULL)
+ cv_broadcast(&tvd->vdev_io_cv);
+ mutex_exit(&tvd->vdev_io_lock);
+}
+
+static void
+zio_vdev_io_retry(void *vdarg)
+{
+ vdev_t *vd = vdarg;
+ zio_t *zio, *zq;
+
+ ASSERT(vd == vd->vdev_top);
+
+ /* XXPOLICY */
+ delay(hz);
+
+ vdev_reopen(vd, &zq);
+
+ while ((zio = zq) != NULL) {
+ zq = zio->io_retry_next;
+ zio->io_retry_next = NULL;
+ dprintf("async retry #%d for I/O to %s offset %llx\n",
+ zio->io_retries, vdev_description(vd), zio->io_offset);
+ zio_next_stage_async(zio);
+ }
+}
+
+static void
+zio_vdev_io_setup(zio_t *zio)
+{
+ vdev_t *vd = zio->io_vd;
+
+ /* XXPOLICY */
+ if (zio->io_retries == 0 && vd == vd->vdev_top)
+ zio->io_flags |= ZIO_FLAG_FAILFAST;
+
+ if (!(zio->io_flags & ZIO_FLAG_PHYSICAL) && vd->vdev_children == 0) {
+ zio->io_flags |= ZIO_FLAG_PHYSICAL;
+ zio->io_offset += VDEV_LABEL_START_SIZE;
+ }
+
+ zio_vdev_io_enter(zio);
+
+ zio_next_stage(zio);
+}
+
+static void
+zio_vdev_io_start(zio_t *zio)
+{
+ blkptr_t *bp = zio->io_bp;
+
+ ASSERT(P2PHASE(zio->io_offset, 1ULL << zio->io_vd->vdev_ashift) == 0);
+ ASSERT(P2PHASE(zio->io_size, 1ULL << zio->io_vd->vdev_ashift) == 0);
+ ASSERT(bp == NULL || ZIO_GET_IOSIZE(zio) == zio->io_size);
+ ASSERT(zio->io_type != ZIO_TYPE_WRITE || (spa_mode & FWRITE));
+
+ vdev_io_start(zio);
+
+ /* zio_next_stage_async() gets called from io completion interrupt */
+}
+
+static void
+zio_vdev_io_done(zio_t *zio)
+{
+ vdev_io_done(zio);
+}
+
+/* XXPOLICY */
+static boolean_t
+zio_should_retry(zio_t *zio)
+{
+ vdev_t *vd = zio->io_vd;
+
+ if (zio->io_error == 0)
+ return (B_FALSE);
+ if (zio->io_delegate_list != NULL)
+ return (B_FALSE);
+ if (vd != vd->vdev_top)
+ return (B_FALSE);
+ if (zio->io_flags & ZIO_FLAG_DONT_RETRY)
+ return (B_FALSE);
+ if (zio->io_retries > 300 &&
+ (zio->io_flags & (ZIO_FLAG_SPECULATIVE | ZIO_FLAG_CANFAIL)))
+ return (B_FALSE);
+ if (zio->io_retries > 1 &&
+ (zio->io_error == ECKSUM || zio->io_error == ENXIO))
+ return (B_FALSE);
+
+ return (B_TRUE);
+}
+
+static void
+zio_vdev_io_assess(zio_t *zio)
+{
+ vdev_t *vd = zio->io_vd;
+ vdev_t *tvd = vd->vdev_top;
+
+ zio_vdev_io_exit(zio);
+
+ ASSERT(zio->io_vsd == NULL);
+
+ /*
+ * If the I/O failed, determine whether we should attempt to retry it.
+ */
+ /* XXPOLICY */
+ if (zio_should_retry(zio)) {
+ zio_t *zq;
+
+ ASSERT(tvd == vd);
+ ASSERT(!(zio->io_flags & ZIO_FLAG_DONT_PROPAGATE));
+
+ zio->io_retries++;
+ zio->io_error = 0;
+ zio->io_flags &= ZIO_FLAG_VDEV_INHERIT;
+ /* XXPOLICY */
+ zio->io_flags &= ~ZIO_FLAG_FAILFAST;
+ zio->io_flags |= ZIO_FLAG_DONT_CACHE;
+ zio->io_stage = ZIO_STAGE_VDEV_IO_SETUP - 1;
+
+ dprintf("retry #%d for %s to %s offset %llx\n",
+ zio->io_retries, zio_type_name[zio->io_type],
+ vdev_description(vd), zio->io_offset);
+
+ /*
+ * If this is the first retry, do it immediately.
+ */
+ /* XXPOLICY */
+ if (zio->io_retries == 1) {
+ zio_next_stage_async(zio);
+ return;
+ }
+
+ /*
+ * This was not the first retry, so go through the
+ * longer enqueue/delay/vdev_reopen() process.
+ */
+ mutex_enter(&tvd->vdev_io_lock);
+ ASSERT(zio->io_retry_next == NULL);
+ zio->io_retry_next = zq = tvd->vdev_io_retry;
+ tvd->vdev_io_retry = zio;
+ mutex_exit(&tvd->vdev_io_lock);
+ if (zq == NULL)
+ (void) taskq_dispatch(
+ tvd->vdev_spa->spa_vdev_retry_taskq,
+ zio_vdev_io_retry, tvd, TQ_SLEEP);
+ return;
+ }
+
+ zio_next_stage(zio);
+}
+
+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 void
+zio_checksum_generate(zio_t *zio)
+{
+ int checksum = zio->io_checksum;
+ blkptr_t *bp = zio->io_bp;
+
+ ASSERT3U(zio->io_size, ==, BP_GET_PSIZE(bp));
+
+ BP_SET_CHECKSUM(bp, checksum);
+ BP_SET_BYTEORDER(bp, ZFS_HOST_BYTEORDER);
+
+ zio_checksum(checksum, &bp->blk_cksum, zio->io_data, zio->io_size);
+
+ zio_next_stage(zio);
+}
+
+static void
+zio_gang_checksum_generate(zio_t *zio)
+{
+ zio_cksum_t zc;
+ zio_gbh_phys_t *gbh = zio->io_data;
+
+ ASSERT3U(zio->io_size, ==, SPA_GANGBLOCKSIZE);
+ ASSERT(DVA_GET_GANG(ZIO_GET_DVA(zio)));
+
+ zio_set_gang_verifier(zio, &gbh->zg_tail.zbt_cksum);
+
+ zio_checksum(ZIO_CHECKSUM_GANG_HEADER, &zc, zio->io_data, zio->io_size);
+
+ zio_next_stage(zio);
+}
+
+static void
+zio_checksum_verify(zio_t *zio)
+{
+ if (zio->io_bp != NULL) {
+ zio->io_error = zio_checksum_error(zio);
+ if (zio->io_error) {
+ dprintf("bad checksum on vdev %s\n",
+ vdev_description(zio->io_vd));
+ }
+ }
+
+ zio_next_stage(zio);
+}
+
+/*
+ * 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);
+}
+
+/*
+ * Set the external verifier for a gang block based on stuff in the bp
+ */
+void
+zio_set_gang_verifier(zio_t *zio, zio_cksum_t *zcp)
+{
+ zcp->zc_word[0] = DVA_GET_VDEV(ZIO_GET_DVA(zio));
+ zcp->zc_word[1] = DVA_GET_OFFSET(ZIO_GET_DVA(zio));
+ zcp->zc_word[2] = zio->io_bp->blk_birth;
+ zcp->zc_word[3] = 0;
+}
+
+/*
+ * ==========================================================================
+ * Define the pipeline
+ * ==========================================================================
+ */
+typedef void zio_pipe_stage_t(zio_t *zio);
+
+static void
+zio_badop(zio_t *zio)
+{
+ panic("Invalid I/O pipeline stage %u for zio %p", zio->io_stage, zio);
+}
+
+zio_pipe_stage_t *zio_pipeline[ZIO_STAGE_DONE + 2] = {
+ zio_badop,
+ zio_wait_children_ready,
+ zio_write_compress,
+ zio_checksum_generate,
+ zio_gang_pipeline,
+ zio_get_gang_header,
+ zio_rewrite_gang_members,
+ zio_free_gang_members,
+ zio_claim_gang_members,
+ zio_dva_allocate,
+ zio_dva_free,
+ zio_dva_claim,
+ zio_gang_checksum_generate,
+ zio_ready,
+ zio_dva_translate,
+ zio_vdev_io_setup,
+ zio_vdev_io_start,
+ zio_vdev_io_done,
+ zio_vdev_io_assess,
+ zio_wait_children_done,
+ zio_checksum_verify,
+ zio_read_gang_members,
+ zio_read_decompress,
+ zio_done,
+ zio_badop
+};
+
+/*
+ * Move an I/O to the next stage of the pipeline and execute that stage.
+ * 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.
+ */
+void
+zio_next_stage(zio_t *zio)
+{
+ uint32_t pipeline = zio->io_pipeline;
+
+ ASSERT(!MUTEX_HELD(&zio->io_lock));
+
+ if (zio->io_error) {
+ dprintf("zio %p vdev %s offset %llx stage %d error %d\n",
+ zio, vdev_description(zio->io_vd),
+ zio->io_offset, zio->io_stage, zio->io_error);
+ if (((1U << zio->io_stage) & ZIO_VDEV_IO_PIPELINE) == 0)
+ pipeline &= ZIO_ERROR_PIPELINE_MASK;
+ }
+
+ while (((1U << ++zio->io_stage) & pipeline) == 0)
+ continue;
+
+ ASSERT(zio->io_stage <= ZIO_STAGE_DONE);
+ ASSERT(zio->io_stalled == 0);
+
+ zio_pipeline[zio->io_stage](zio);
+}
+
+void
+zio_next_stage_async(zio_t *zio)
+{
+ taskq_t *tq;
+ uint32_t pipeline = zio->io_pipeline;
+
+ ASSERT(!MUTEX_HELD(&zio->io_lock));
+
+ if (zio->io_error) {
+ dprintf("zio %p vdev %s offset %llx stage %d error %d\n",
+ zio, vdev_description(zio->io_vd),
+ zio->io_offset, zio->io_stage, zio->io_error);
+ if (((1U << zio->io_stage) & ZIO_VDEV_IO_PIPELINE) == 0)
+ pipeline &= ZIO_ERROR_PIPELINE_MASK;
+ }
+
+ while (((1U << ++zio->io_stage) & pipeline) == 0)
+ continue;
+
+ ASSERT(zio->io_stage <= ZIO_STAGE_DONE);
+ ASSERT(zio->io_stalled == 0);
+
+ /*
+ * For performance, we'll probably want two sets of task queues:
+ * per-CPU issue taskqs and per-CPU completion taskqs. The per-CPU
+ * part is for read performance: since we have to make a pass over
+ * the data to checksum it anyway, we want to do this on the same CPU
+ * that issued the read, because (assuming CPU scheduling affinity)
+ * that thread is probably still there. Getting this optimization
+ * right avoids performance-hostile cache-to-cache transfers.
+ *
+ * Note that having two sets of task queues is also necessary for
+ * correctness: if all of the issue threads get bogged down waiting
+ * for dependent reads (e.g. metaslab freelist) to complete, then
+ * there won't be any threads available to service I/O completion
+ * interrupts.
+ */
+ if ((1U << zio->io_stage) & zio->io_async_stages) {
+ if (zio->io_stage < ZIO_STAGE_VDEV_IO_DONE)
+ tq = zio->io_spa->spa_zio_issue_taskq[zio->io_type];
+ else
+ tq = zio->io_spa->spa_zio_intr_taskq[zio->io_type];
+ (void) taskq_dispatch(tq,
+ (task_func_t *)zio_pipeline[zio->io_stage], zio, TQ_SLEEP);
+ } else {
+ zio_pipeline[zio->io_stage](zio);
+ }
+}
+
+/*
+ * Try to allocate an intent log block. Return 0 on success, errno on failure.
+ */
+int
+zio_alloc_blk(spa_t *spa, int checksum, uint64_t size, blkptr_t *bp,
+ uint64_t txg)
+{
+ int error;
+
+ spa_config_enter(spa, RW_READER);
+
+ BP_ZERO(bp);
+
+ error = metaslab_alloc(spa, size, BP_IDENTITY(bp), txg);
+
+ if (error == 0) {
+ BP_SET_CHECKSUM(bp, checksum);
+ BP_SET_LSIZE(bp, size);
+ BP_SET_PSIZE(bp, size);
+ BP_SET_COMPRESS(bp, ZIO_COMPRESS_OFF);
+ BP_SET_TYPE(bp, DMU_OT_INTENT_LOG);
+ BP_SET_LEVEL(bp, 0);
+ BP_SET_BYTEORDER(bp, ZFS_HOST_BYTEORDER);
+ bp->blk_birth = txg;
+ }
+
+ spa_config_exit(spa);
+
+ 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(DVA_GET_GANG(BP_IDENTITY(bp)) == 0);
+
+ dprintf_bp(bp, "txg %llu: ", txg);
+
+ spa_config_enter(spa, RW_READER);
+
+ metaslab_free(spa, BP_IDENTITY(bp), txg);
+
+ spa_config_exit(spa);
+}