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zfs/module/zfs/zio.c

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/*
* 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 2009 Sun Microsystems, Inc. All rights reserved.
* Use is subject to license terms.
*/
#include <sys/zfs_context.h>
#include <sys/fm/fs/zfs.h>
#include <sys/spa.h>
#include <sys/txg.h>
#include <sys/spa_impl.h>
#include <sys/vdev_impl.h>
#include <sys/zio_impl.h>
#include <sys/zio_compress.h>
#include <sys/zio_checksum.h>
/*
* ==========================================================================
* I/O priority table
* ==========================================================================
*/
uint8_t zio_priority_table[ZIO_PRIORITY_TABLE_SIZE] = {
0, /* ZIO_PRIORITY_NOW */
0, /* ZIO_PRIORITY_SYNC_READ */
0, /* ZIO_PRIORITY_SYNC_WRITE */
6, /* ZIO_PRIORITY_ASYNC_READ */
4, /* ZIO_PRIORITY_ASYNC_WRITE */
4, /* ZIO_PRIORITY_FREE */
0, /* ZIO_PRIORITY_CACHE_FILL */
0, /* ZIO_PRIORITY_LOG_WRITE */
10, /* ZIO_PRIORITY_RESILVER */
20, /* ZIO_PRIORITY_SCRUB */
};
/*
* ==========================================================================
* I/O type descriptions
* ==========================================================================
*/
char *zio_type_name[ZIO_TYPES] = {
"null", "read", "write", "free", "claim", "ioctl" };
#define SYNC_PASS_DEFERRED_FREE 1 /* defer frees after this pass */
#define SYNC_PASS_DONT_COMPRESS 4 /* don't compress after this pass */
#define SYNC_PASS_REWRITE 1 /* rewrite new bps after this pass */
/*
* ==========================================================================
* I/O kmem caches
* ==========================================================================
*/
kmem_cache_t *zio_cache;
kmem_cache_t *zio_link_cache;
kmem_cache_t *zio_buf_cache[SPA_MAXBLOCKSIZE >> SPA_MINBLOCKSHIFT];
kmem_cache_t *zio_data_buf_cache[SPA_MAXBLOCKSIZE >> SPA_MINBLOCKSHIFT];
int zio_bulk_flags = 0;
#ifdef _KERNEL
extern vmem_t *zio_alloc_arena;
#endif
/*
* An allocating zio is one that either currently has the DVA allocate
* stage set or will have it later in its lifetime.
*/
#define IO_IS_ALLOCATING(zio) \
((zio)->io_orig_pipeline & (1U << ZIO_STAGE_DVA_ALLOCATE))
void
zio_init(void)
{
size_t c;
vmem_t *data_alloc_arena = NULL;
#ifdef _KERNEL
data_alloc_arena = zio_alloc_arena;
#endif
zio_cache = kmem_cache_create("zio_cache",
sizeof (zio_t), 0, NULL, NULL, NULL, NULL, NULL, 0);
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;
while (p2 & (p2 - 1))
p2 &= p2 - 1;
if (size <= 4 * SPA_MINBLOCKSIZE) {
align = SPA_MINBLOCKSIZE;
} else if (P2PHASE(size, PAGESIZE) == 0) {
align = PAGESIZE;
} else if (P2PHASE(size, p2 >> 2) == 0) {
align = p2 >> 2;
}
if (align != 0) {
char name[36];
(void) sprintf(name, "zio_buf_%lu", (ulong_t)size);
zio_buf_cache[c] = kmem_cache_create(name, size,
align, NULL, NULL, NULL, NULL, NULL,
KMC_NODEBUG | zio_bulk_flags);
(void) sprintf(name, "zio_data_buf_%lu", (ulong_t)size);
zio_data_buf_cache[c] = kmem_cache_create(name, size,
align, NULL, NULL, NULL, NULL, data_alloc_arena,
KMC_NODEBUG | zio_bulk_flags);
}
}
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);
zio_buf_free(zio->io_data, zt->zt_bufsize);
zio->io_data = zt->zt_orig_data;
zio->io_size = zt->zt_orig_size;
zio->io_transform_stack = zt->zt_next;
kmem_free(zt, sizeof (zio_transform_t));
}
}
/*
* ==========================================================================
* I/O transform callbacks for subblocks and decompression
* ==========================================================================
*/
static void
zio_subblock(zio_t *zio, void *data, uint64_t size)
{
ASSERT(zio->io_size > size);
if (zio->io_type == ZIO_TYPE_READ)
bcopy(zio->io_data, data, size);
}
static void
zio_decompress(zio_t *zio, void *data, uint64_t size)
{
if (zio->io_error == 0 &&
zio_decompress_data(BP_GET_COMPRESS(zio->io_bp),
zio->io_data, zio->io_size, data, size) != 0)
zio->io_error = EIO;
}
/*
* ==========================================================================
* I/O parent/child relationships and pipeline interlocks
* ==========================================================================
*/
/*
* 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);
int w;
/*
* 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 (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);
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);
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--;
zio->io_stall = countp;
waiting = B_TRUE;
}
mutex_exit(&zio->io_lock);
return (waiting);
}
static void
zio_notify_parent(zio_t *pio, zio_t *zio, enum zio_wait_type wait)
{
uint64_t *countp = &pio->io_children[zio->io_child_type][wait];
int *errorp = &pio->io_child_error[zio->io_child_type];
mutex_enter(&pio->io_lock);
if (zio->io_error && !(zio->io_flags & ZIO_FLAG_DONT_PROPAGATE))
*errorp = zio_worst_error(*errorp, zio->io_error);
pio->io_reexecute |= zio->io_reexecute;
ASSERT3U(*countp, >, 0);
if (--*countp == 0 && pio->io_stall == countp) {
pio->io_stall = NULL;
mutex_exit(&pio->io_lock);
zio_execute(pio);
} else {
mutex_exit(&pio->io_lock);
}
}
static void
zio_inherit_child_errors(zio_t *zio, enum zio_child c)
{
if (zio->io_child_error[c] != 0 && zio->io_error == 0)
zio->io_error = zio->io_child_error[c];
}
/*
* ==========================================================================
* Create the various types of I/O (read, write, free, etc)
* ==========================================================================
*/
static zio_t *
zio_create(zio_t *pio, spa_t *spa, uint64_t txg, blkptr_t *bp,
void *data, uint64_t size, zio_done_func_t *done, void *private,
zio_type_t type, int priority, int flags, vdev_t *vd, uint64_t offset,
const zbookmark_t *zb, uint8_t stage, uint32_t pipeline)
{
zio_t *zio;
ASSERT3U(size, <=, SPA_MAXBLOCKSIZE);
ASSERT(P2PHASE(size, SPA_MINBLOCKSIZE) == 0);
ASSERT(P2PHASE(offset, SPA_MINBLOCKSIZE) == 0);
ASSERT(!vd || spa_config_held(spa, SCL_STATE_ALL, RW_READER));
ASSERT(!bp || !(flags & ZIO_FLAG_CONFIG_WRITER));
ASSERT(vd || stage == ZIO_STAGE_OPEN);
zio = kmem_cache_alloc(zio_cache, KM_SLEEP);
bzero(zio, sizeof (zio_t));
mutex_init(&zio->io_lock, NULL, MUTEX_DEFAULT, NULL);
cv_init(&zio->io_cv, NULL, CV_DEFAULT, NULL);
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
zio->io_child_type = ZIO_CHILD_LOGICAL;
if (bp != NULL) {
zio->io_bp = bp;
zio->io_bp_copy = *bp;
zio->io_bp_orig = *bp;
if (type != ZIO_TYPE_WRITE)
zio->io_bp = &zio->io_bp_copy; /* so caller can free */
if (zio->io_child_type == ZIO_CHILD_LOGICAL)
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_data = data;
zio->io_size = size;
zio->io_done = done;
zio->io_private = private;
zio->io_type = type;
zio->io_priority = priority;
zio->io_vd = vd;
zio->io_offset = offset;
zio->io_orig_flags = zio->io_flags = flags;
zio->io_orig_stage = zio->io_stage = stage;
zio->io_orig_pipeline = zio->io_pipeline = pipeline;
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, int 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, int 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, int flags, const zbookmark_t *zb)
{
zio_t *zio;
zio = zio_create(pio, spa, bp->blk_birth, (blkptr_t *)bp,
data, size, done, private,
ZIO_TYPE_READ, priority, flags, NULL, 0, zb,
ZIO_STAGE_OPEN, ZIO_READ_PIPELINE);
return (zio);
}
void
zio_skip_write(zio_t *zio)
{
ASSERT(zio->io_type == ZIO_TYPE_WRITE);
ASSERT(zio->io_stage == ZIO_STAGE_READY);
ASSERT(!BP_IS_GANG(zio->io_bp));
zio->io_pipeline &= ~ZIO_VDEV_IO_STAGES;
}
zio_t *
zio_write(zio_t *pio, spa_t *spa, uint64_t txg, blkptr_t *bp,
void *data, uint64_t size, zio_prop_t *zp,
zio_done_func_t *ready, zio_done_func_t *done, void *private,
int priority, int flags, const zbookmark_t *zb)
{
zio_t *zio;
ASSERT(zp->zp_checksum >= ZIO_CHECKSUM_OFF &&
zp->zp_checksum < ZIO_CHECKSUM_FUNCTIONS &&
zp->zp_compress >= ZIO_COMPRESS_OFF &&
zp->zp_compress < ZIO_COMPRESS_FUNCTIONS &&
zp->zp_type < DMU_OT_NUMTYPES &&
zp->zp_level < 32 &&
zp->zp_ndvas > 0 &&
zp->zp_ndvas <= spa_max_replication(spa));
ASSERT(ready != NULL);
zio = zio_create(pio, spa, txg, bp, data, size, done, private,
ZIO_TYPE_WRITE, priority, flags, NULL, 0, zb,
ZIO_STAGE_OPEN, ZIO_WRITE_PIPELINE);
zio->io_ready = ready;
zio->io_prop = *zp;
return (zio);
}
zio_t *
zio_rewrite(zio_t *pio, spa_t *spa, uint64_t txg, blkptr_t *bp, void *data,
uint64_t size, zio_done_func_t *done, void *private, int priority,
int flags, zbookmark_t *zb)
{
zio_t *zio;
zio = zio_create(pio, spa, txg, bp, data, size, done, private,
ZIO_TYPE_WRITE, priority, flags, NULL, 0, zb,
ZIO_STAGE_OPEN, ZIO_REWRITE_PIPELINE);
return (zio);
}
zio_t *
zio_free(zio_t *pio, spa_t *spa, uint64_t txg, blkptr_t *bp,
zio_done_func_t *done, void *private, int flags)
{
zio_t *zio;
ASSERT(!BP_IS_HOLE(bp));
if (bp->blk_fill == BLK_FILL_ALREADY_FREED)
return (zio_null(pio, spa, NULL, NULL, NULL, flags));
if (txg == spa->spa_syncing_txg &&
spa_sync_pass(spa) > SYNC_PASS_DEFERRED_FREE) {
bplist_enqueue_deferred(&spa->spa_sync_bplist, bp);
return (zio_null(pio, spa, NULL, NULL, NULL, flags));
}
zio = zio_create(pio, spa, txg, bp, NULL, BP_GET_PSIZE(bp),
done, private, ZIO_TYPE_FREE, ZIO_PRIORITY_FREE, flags,
NULL, 0, NULL, ZIO_STAGE_OPEN, ZIO_FREE_PIPELINE);
return (zio);
}
zio_t *
zio_claim(zio_t *pio, spa_t *spa, uint64_t txg, blkptr_t *bp,
zio_done_func_t *done, void *private, int flags)
{
zio_t *zio;
/*
* A claim is an allocation of a specific block. Claims are needed
* to support immediate writes in the intent log. The issue is that
* immediate writes contain committed data, but in a txg that was
* *not* committed. Upon opening the pool after an unclean shutdown,
* the intent log claims all blocks that contain immediate write data
* so that the SPA knows they're in use.
*
* All claims *must* be resolved in the first txg -- before the SPA
* starts allocating blocks -- so that nothing is allocated twice.
*/
ASSERT3U(spa->spa_uberblock.ub_rootbp.blk_birth, <, spa_first_txg(spa));
ASSERT3U(spa_first_txg(spa), <=, txg);
zio = zio_create(pio, spa, txg, bp, NULL, BP_GET_PSIZE(bp),
done, private, ZIO_TYPE_CLAIM, ZIO_PRIORITY_NOW, flags,
NULL, 0, NULL, ZIO_STAGE_OPEN, ZIO_CLAIM_PIPELINE);
return (zio);
}
zio_t *
zio_ioctl(zio_t *pio, spa_t *spa, vdev_t *vd, int cmd,
zio_done_func_t *done, void *private, int priority, int flags)
{
zio_t *zio;
int c;
if (vd->vdev_children == 0) {
zio = zio_create(pio, spa, 0, NULL, NULL, 0, done, private,
ZIO_TYPE_IOCTL, priority, flags, vd, 0, NULL,
ZIO_STAGE_OPEN, ZIO_IOCTL_PIPELINE);
zio->io_cmd = cmd;
} else {
zio = zio_null(pio, spa, NULL, NULL, NULL, flags);
for (c = 0; c < vd->vdev_children; c++)
zio_nowait(zio_ioctl(zio, spa, vd->vdev_child[c], cmd,
done, private, priority, flags));
}
return (zio);
}
zio_t *
zio_read_phys(zio_t *pio, vdev_t *vd, uint64_t offset, uint64_t size,
void *data, int checksum, zio_done_func_t *done, void *private,
int priority, int flags, boolean_t labels)
{
zio_t *zio;
ASSERT(vd->vdev_children == 0);
ASSERT(!labels || offset + size <= VDEV_LABEL_START_SIZE ||
offset >= vd->vdev_psize - VDEV_LABEL_END_SIZE);
ASSERT3U(offset + size, <=, vd->vdev_psize);
zio = zio_create(pio, vd->vdev_spa, 0, NULL, data, size, done, private,
ZIO_TYPE_READ, priority, flags, vd, offset, NULL,
ZIO_STAGE_OPEN, ZIO_READ_PHYS_PIPELINE);
zio->io_prop.zp_checksum = checksum;
return (zio);
}
zio_t *
zio_write_phys(zio_t *pio, vdev_t *vd, uint64_t offset, uint64_t size,
void *data, int checksum, zio_done_func_t *done, void *private,
int priority, int flags, boolean_t labels)
{
zio_t *zio;
ASSERT(vd->vdev_children == 0);
ASSERT(!labels || offset + size <= VDEV_LABEL_START_SIZE ||
offset >= vd->vdev_psize - VDEV_LABEL_END_SIZE);
ASSERT3U(offset + size, <=, vd->vdev_psize);
zio = zio_create(pio, vd->vdev_spa, 0, NULL, data, size, done, private,
ZIO_TYPE_WRITE, priority, flags, vd, offset, NULL,
ZIO_STAGE_OPEN, ZIO_WRITE_PHYS_PIPELINE);
zio->io_prop.zp_checksum = checksum;
if (zio_checksum_table[checksum].ci_zbt) {
/*
* zbt checksums are necessarily destructive -- they modify
* the end of the write buffer to hold the verifier/checksum.
* Therefore, we must make a local copy in case the data is
* being written to multiple places in parallel.
*/
void *wbuf = zio_buf_alloc(size);
bcopy(data, wbuf, size);
zio_push_transform(zio, wbuf, size, size, NULL);
}
return (zio);
}
/*
* Create a child I/O to do some work for us.
*/
zio_t *
zio_vdev_child_io(zio_t *pio, blkptr_t *bp, vdev_t *vd, uint64_t offset,
void *data, uint64_t size, int type, int priority, int flags,
zio_done_func_t *done, void *private)
{
uint32_t pipeline = ZIO_VDEV_CHILD_PIPELINE;
zio_t *zio;
ASSERT(vd->vdev_parent ==
(pio->io_vd ? pio->io_vd : pio->io_spa->spa_root_vdev));
if (type == ZIO_TYPE_READ && bp != NULL) {
/*
* If we have the bp, then the child should perform the
* checksum and the parent need not. This pushes error
* detection as close to the leaves as possible and
* eliminates redundant checksums in the interior nodes.
*/
pipeline |= 1U << ZIO_STAGE_CHECKSUM_VERIFY;
pio->io_pipeline &= ~(1U << ZIO_STAGE_CHECKSUM_VERIFY);
}
if (vd->vdev_children == 0)
offset += VDEV_LABEL_START_SIZE;
zio = zio_create(pio, pio->io_spa, pio->io_txg, bp, data, size,
done, private, type, priority,
(pio->io_flags & ZIO_FLAG_VDEV_INHERIT) |
ZIO_FLAG_CANFAIL | ZIO_FLAG_DONT_PROPAGATE | flags,
vd, offset, &pio->io_bookmark,
ZIO_STAGE_VDEV_IO_START - 1, pipeline);
return (zio);
}
zio_t *
zio_vdev_delegated_io(vdev_t *vd, uint64_t offset, void *data, uint64_t size,
int type, int priority, int flags, zio_done_func_t *done, void *private)
{
zio_t *zio;
ASSERT(vd->vdev_ops->vdev_op_leaf);
zio = zio_create(NULL, vd->vdev_spa, 0, NULL,
data, size, done, private, type, priority,
flags | ZIO_FLAG_CANFAIL | ZIO_FLAG_DONT_RETRY,
vd, offset, NULL,
ZIO_STAGE_VDEV_IO_START - 1, ZIO_VDEV_CHILD_PIPELINE);
return (zio);
}
void
zio_flush(zio_t *zio, vdev_t *vd)
{
zio_nowait(zio_ioctl(zio, zio->io_spa, vd, DKIOCFLUSHWRITECACHE,
NULL, NULL, ZIO_PRIORITY_NOW,
ZIO_FLAG_CANFAIL | ZIO_FLAG_DONT_PROPAGATE | ZIO_FLAG_DONT_RETRY));
}
/*
* ==========================================================================
* Prepare to read and write logical blocks
* ==========================================================================
*/
static int
zio_read_bp_init(zio_t *zio)
{
blkptr_t *bp = zio->io_bp;
if (BP_GET_COMPRESS(bp) != ZIO_COMPRESS_OFF &&
zio->io_child_type == ZIO_CHILD_LOGICAL &&
!(zio->io_flags & ZIO_FLAG_RAW)) {
uint64_t csize = BP_GET_PSIZE(bp);
void *cbuf = zio_buf_alloc(csize);
zio_push_transform(zio, cbuf, csize, csize, zio_decompress);
}
if (!dmu_ot[BP_GET_TYPE(bp)].ot_metadata && BP_GET_LEVEL(bp) == 0)
zio->io_flags |= ZIO_FLAG_DONT_CACHE;
return (ZIO_PIPELINE_CONTINUE);
}
static int
zio_write_bp_init(zio_t *zio)
{
zio_prop_t *zp = &zio->io_prop;
int compress = zp->zp_compress;
blkptr_t *bp = zio->io_bp;
void *cbuf;
uint64_t lsize = zio->io_size;
uint64_t csize = lsize;
uint64_t cbufsize = 0;
int pass = 1;
/*
* If our children haven't all reached the ready stage,
* wait for them and then repeat this pipeline stage.
*/
if (zio_wait_for_children(zio, ZIO_CHILD_GANG, ZIO_WAIT_READY) ||
zio_wait_for_children(zio, ZIO_CHILD_LOGICAL, ZIO_WAIT_READY))
return (ZIO_PIPELINE_STOP);
if (!IO_IS_ALLOCATING(zio))
return (ZIO_PIPELINE_CONTINUE);
ASSERT(compress != ZIO_COMPRESS_INHERIT);
if (bp->blk_birth == zio->io_txg) {
/*
* We're rewriting an existing block, which means we're
* working on behalf of spa_sync(). For spa_sync() to
* converge, it must eventually be the case that we don't
* have to allocate new blocks. But compression changes
* the blocksize, which forces a reallocate, and makes
* convergence take longer. Therefore, after the first
* few passes, stop compressing to ensure convergence.
*/
pass = spa_sync_pass(zio->io_spa);
if (pass > SYNC_PASS_DONT_COMPRESS)
compress = ZIO_COMPRESS_OFF;
/* Make sure someone doesn't change their mind on overwrites */
ASSERT(MIN(zp->zp_ndvas + BP_IS_GANG(bp),
spa_max_replication(zio->io_spa)) == BP_GET_NDVAS(bp));
}
if (compress != ZIO_COMPRESS_OFF) {
if (!zio_compress_data(compress, zio->io_data, zio->io_size,
&cbuf, &csize, &cbufsize)) {
compress = ZIO_COMPRESS_OFF;
} else if (csize != 0) {
zio_push_transform(zio, cbuf, csize, cbufsize, NULL);
}
}
/*
* The final pass of spa_sync() must be all rewrites, but the first
* few passes offer a trade-off: allocating blocks defers convergence,
* but newly allocated blocks are sequential, so they can be written
* to disk faster. Therefore, we allow the first few passes of
* spa_sync() to allocate new blocks, but force rewrites after that.
* There should only be a handful of blocks after pass 1 in any case.
*/
if (bp->blk_birth == zio->io_txg && BP_GET_PSIZE(bp) == csize &&
pass > SYNC_PASS_REWRITE) {
uint32_t gang_stages = zio->io_pipeline & ZIO_GANG_STAGES;
ASSERT(csize != 0);
zio->io_pipeline = ZIO_REWRITE_PIPELINE | gang_stages;
zio->io_flags |= ZIO_FLAG_IO_REWRITE;
} else {
BP_ZERO(bp);
zio->io_pipeline = ZIO_WRITE_PIPELINE;
}
if (csize == 0) {
zio->io_pipeline = ZIO_INTERLOCK_PIPELINE;
} else {
ASSERT(zp->zp_checksum != ZIO_CHECKSUM_GANG_HEADER);
BP_SET_LSIZE(bp, lsize);
BP_SET_PSIZE(bp, csize);
BP_SET_COMPRESS(bp, compress);
BP_SET_CHECKSUM(bp, zp->zp_checksum);
BP_SET_TYPE(bp, zp->zp_type);
BP_SET_LEVEL(bp, zp->zp_level);
BP_SET_BYTEORDER(bp, ZFS_HOST_BYTEORDER);
}
return (ZIO_PIPELINE_CONTINUE);
}
/*
* ==========================================================================
* Execute the I/O pipeline
* ==========================================================================
*/
static void
zio_taskq_dispatch(zio_t *zio, enum zio_taskq_type q)
{
zio_type_t t = zio->io_type;
/*
* If we're a config writer 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;
(void) taskq_dispatch(zio->io_spa->spa_zio_taskq[t][q],
(task_func_t *)zio_execute, zio, TQ_NOSLEEP);
}
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;
zio_type_t t;
for (t = 0; t < ZIO_TYPES; t++)
if (taskq_member(spa->spa_zio_taskq[t][q], executor))
return (B_TRUE);
return (B_FALSE);
}
static int
zio_issue_async(zio_t *zio)
{
zio_taskq_dispatch(zio, ZIO_TASKQ_ISSUE);
return (ZIO_PIPELINE_STOP);
}
void
zio_interrupt(zio_t *zio)
{
zio_taskq_dispatch(zio, ZIO_TASKQ_INTERRUPT);
}
/*
* Execute the I/O pipeline until one of the following occurs:
* (1) the I/O completes; (2) the pipeline stalls waiting for
* dependent child I/Os; (3) the I/O issues, so we're waiting
* for an I/O completion interrupt; (4) the I/O is delegated by
* vdev-level caching or aggregation; (5) the I/O is deferred
* due to vdev-level queueing; (6) the I/O is handed off to
* another thread. In all cases, the pipeline stops whenever
* there's no CPU work; it never burns a thread in cv_wait().
*
* There's no locking on io_stage because there's no legitimate way
* for multiple threads to be attempting to process the same I/O.
*/
static zio_pipe_stage_t *zio_pipeline[ZIO_STAGES];
void
zio_execute(zio_t *zio)
{
zio->io_executor = curthread;
while (zio->io_stage < ZIO_STAGE_DONE) {
uint32_t pipeline = zio->io_pipeline;
zio_stage_t stage = zio->io_stage;
int rv;
ASSERT(!MUTEX_HELD(&zio->io_lock));
while (((1U << ++stage) & pipeline) == 0)
continue;
ASSERT(stage <= ZIO_STAGE_DONE);
ASSERT(zio->io_stall == NULL);
/*
* If we are in interrupt context and this pipeline stage
* will grab a config lock that is held across I/O,
* issue async to avoid deadlock.
*/
if (((1U << stage) & ZIO_CONFIG_LOCK_BLOCKING_STAGES) &&
zio->io_vd == NULL &&
zio_taskq_member(zio, ZIO_TASKQ_INTERRUPT)) {
zio_taskq_dispatch(zio, ZIO_TASKQ_ISSUE);
return;
}
zio->io_stage = stage;
rv = zio_pipeline[stage](zio);
if (rv == ZIO_PIPELINE_STOP)
return;
ASSERT(rv == ZIO_PIPELINE_CONTINUE);
}
}
/*
* ==========================================================================
* Initiate I/O, either sync or async
* ==========================================================================
*/
int
zio_wait(zio_t *zio)
{
int error;
ASSERT(zio->io_stage == ZIO_STAGE_OPEN);
ASSERT(zio->io_executor == NULL);
zio->io_waiter = curthread;
zio_execute(zio);
mutex_enter(&zio->io_lock);
while (zio->io_executor != NULL)
cv_wait(&zio->io_cv, &zio->io_lock);
mutex_exit(&zio->io_lock);
error = zio->io_error;
zio_destroy(zio);
return (error);
}
void
zio_nowait(zio_t *zio)
{
ASSERT(zio->io_executor == NULL);
if (zio->io_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;
int c, w;
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 (w = 0; w < ZIO_WAIT_TYPES; w++)
pio->io_state[w] = 0;
for (c = 0; c < ZIO_CHILD_TYPES; c++)
pio->io_child_error[c] = 0;
if (IO_IS_ALLOCATING(pio)) {
/*
* Remember the failed bp so that the io_ready() callback
* can update its accounting upon reexecution. The block
* was already freed in zio_done(); we indicate this with
* a fill count of -1 so that zio_free() knows to skip it.
*/
blkptr_t *bp = pio->io_bp;
ASSERT(bp->blk_birth == 0 || bp->blk_birth == pio->io_txg);
bp->blk_fill = BLK_FILL_ALREADY_FREED;
pio->io_bp_orig = *bp;
BP_ZERO(bp);
}
/*
* As we reexecute pio's children, new children could be created.
* New children go to the head of 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 (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));
}
} else {
zio = zio_rewrite(pio, pio->io_spa, pio->io_txg, bp,
data, BP_GET_PSIZE(bp), NULL, NULL, pio->io_priority,
ZIO_GANG_CHILD_FLAGS(pio), &pio->io_bookmark);
}
return (zio);
}
/* ARGSUSED */
zio_t *
zio_free_gang(zio_t *pio, blkptr_t *bp, zio_gang_node_t *gn, void *data)
{
return (zio_free(pio, pio->io_spa, pio->io_txg, bp,
NULL, NULL, ZIO_GANG_CHILD_FLAGS(pio)));
}
/* ARGSUSED */
zio_t *
zio_claim_gang(zio_t *pio, blkptr_t *bp, zio_gang_node_t *gn, void *data)
{
return (zio_claim(pio, pio->io_spa, pio->io_txg, bp,
NULL, NULL, ZIO_GANG_CHILD_FLAGS(pio)));
}
static zio_gang_issue_func_t *zio_gang_issue_func[ZIO_TYPES] = {
NULL,
zio_read_gang,
zio_rewrite_gang,
zio_free_gang,
zio_claim_gang,
NULL
};
static void zio_gang_tree_assemble_done(zio_t *zio);
static zio_gang_node_t *
zio_gang_node_alloc(zio_gang_node_t **gnpp)
{
zio_gang_node_t *gn;
ASSERT(*gnpp == NULL);
gn = kmem_zalloc(sizeof (*gn), KM_SLEEP);
gn->gn_gbh = zio_buf_alloc(SPA_GANGBLOCKSIZE);
*gnpp = gn;
return (gn);
}
static void
zio_gang_node_free(zio_gang_node_t **gnpp)
{
zio_gang_node_t *gn = *gnpp;
int g;
for (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;
int g;
if (gn == NULL)
return;
for (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;
int g;
ASSERT(gio == zio_unique_parent(zio));
ASSERT(zio_walk_children(zio) == NULL);
if (zio->io_error)
return;
if (BP_SHOULD_BYTESWAP(bp))
byteswap_uint64_array(zio->io_data, zio->io_size);
ASSERT(zio->io_data == gn->gn_gbh);
ASSERT(zio->io_size == SPA_GANGBLOCKSIZE);
ASSERT(gn->gn_gbh->zg_tail.zbt_magic == ZBT_MAGIC);
for (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;
int g;
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.zbt_magic == ZBT_MAGIC);
for (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);
ASSERTV(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;
int d;
if (BP_IS_HOLE(zio->io_bp))
return;
ASSERT(BP_IS_HOLE(&zio->io_bp_orig));
ASSERT(zio->io_child_type == ZIO_CHILD_GANG);
ASSERT3U(zio->io_prop.zp_ndvas, ==, gio->io_prop.zp_ndvas);
ASSERT3U(zio->io_prop.zp_ndvas, <=, BP_GET_NDVAS(zio->io_bp));
ASSERT3U(pio->io_prop.zp_ndvas, <=, BP_GET_NDVAS(pio->io_bp));
ASSERT3U(BP_GET_NDVAS(zio->io_bp), <=, BP_GET_NDVAS(pio->io_bp));
mutex_enter(&pio->io_lock);
for (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 ndvas = gio->io_prop.zp_ndvas;
int gbh_ndvas = MIN(ndvas + 1, spa_max_replication(spa));
zio_prop_t zp;
int g, error;
error = metaslab_alloc(spa, spa->spa_normal_class, SPA_GANGBLOCKSIZE,
bp, gbh_ndvas, 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 (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_ndvas = gio->io_prop.zp_ndvas;
zio_nowait(zio_write(zio, spa, txg, &gbh->zg_blkptr[g],
(char *)pio->io_data + (pio->io_size - resid), lsize, &zp,
zio_write_gang_member_ready, NULL, &gn->gn_child[g],
pio->io_priority, ZIO_GANG_CHILD_FLAGS(pio),
&pio->io_bookmark));
}
/*
* Set pio's pipeline to just wait for zio to finish.
*/
pio->io_pipeline = ZIO_INTERLOCK_PIPELINE;
zio_nowait(zio);
return (ZIO_PIPELINE_CONTINUE);
}
/*
* ==========================================================================
* Allocate and free blocks
* ==========================================================================
*/
static int
zio_dva_allocate(zio_t *zio)
{
spa_t *spa = zio->io_spa;
metaslab_class_t *mc = spa->spa_normal_class;
blkptr_t *bp = zio->io_bp;
int error;
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_ndvas, >, 0);
ASSERT3U(zio->io_prop.zp_ndvas, <=, spa_max_replication(spa));
ASSERT3U(zio->io_size, ==, BP_GET_PSIZE(bp));
error = metaslab_alloc(spa, mc, zio->io_size, bp,
zio->io_prop.zp_ndvas, zio->io_txg, NULL, 0);
if (error) {
if (error == ENOSPC && zio->io_size > SPA_MINBLOCKSIZE)
return (zio_write_gang_block(zio));
zio->io_error = error;
}
return (ZIO_PIPELINE_CONTINUE);
}
static int
zio_dva_free(zio_t *zio)
{
metaslab_free(zio->io_spa, zio->io_bp, zio->io_txg, B_FALSE);
return (ZIO_PIPELINE_CONTINUE);
}
static int
zio_dva_claim(zio_t *zio)
{
int error;
error = metaslab_claim(zio->io_spa, zio->io_bp, zio->io_txg);
if (error)
zio->io_error = error;
return (ZIO_PIPELINE_CONTINUE);
}
/*
* Undo an allocation. This is used by zio_done() when an I/O fails
* and we want to give back the block we just allocated.
* This handles both normal blocks and gang blocks.
*/
static void
zio_dva_unallocate(zio_t *zio, zio_gang_node_t *gn, blkptr_t *bp)
{
spa_t *spa = zio->io_spa;
boolean_t now = !(zio->io_flags & ZIO_FLAG_IO_REWRITE);
int g;
ASSERT(bp->blk_birth == zio->io_txg || BP_IS_HOLE(bp));
if (zio->io_bp == bp && !now) {
/*
* This is a rewrite for sync-to-convergence.
* We can't do a metaslab_free(NOW) because bp wasn't allocated
* during this sync pass, which means that metaslab_sync()
* already committed the allocation.
*/
ASSERT(DVA_EQUAL(BP_IDENTITY(bp),
BP_IDENTITY(&zio->io_bp_orig)));
ASSERT(spa_sync_pass(spa) > 1);
if (BP_IS_GANG(bp) && gn == NULL) {
/*
* This is a gang leader whose gang header(s) we
* couldn't read now, so defer the free until later.
* The block should still be intact because without
* the headers, we'd never even start the rewrite.
*/
bplist_enqueue_deferred(&spa->spa_sync_bplist, bp);
return;
}
}
if (!BP_IS_HOLE(bp))
metaslab_free(spa, bp, bp->blk_birth, now);
if (gn != NULL) {
for (g = 0; g < SPA_GBH_NBLKPTRS; g++) {
zio_dva_unallocate(zio, gn->gn_child[g],
&gn->gn_gbh->zg_blkptr[g]);
}
}
}
/*
* Try to allocate an intent log block. Return 0 on success, errno on failure.
*/
int
zio_alloc_blk(spa_t *spa, uint64_t size, blkptr_t *new_bp, blkptr_t *old_bp,
uint64_t txg)
{
int error;
error = metaslab_alloc(spa, spa->spa_log_class, size,
new_bp, 1, txg, old_bp, METASLAB_HINTBP_AVOID);
if (error)
error = metaslab_alloc(spa, spa->spa_normal_class, size,
new_bp, 1, txg, old_bp, METASLAB_HINTBP_AVOID);
if (error == 0) {
BP_SET_LSIZE(new_bp, size);
BP_SET_PSIZE(new_bp, size);
BP_SET_COMPRESS(new_bp, ZIO_COMPRESS_OFF);
BP_SET_CHECKSUM(new_bp, ZIO_CHECKSUM_ZILOG);
BP_SET_TYPE(new_bp, DMU_OT_INTENT_LOG);
BP_SET_LEVEL(new_bp, 0);
BP_SET_BYTEORDER(new_bp, ZFS_HOST_BYTEORDER);
}
return (error);
}
/*
* Free an intent log block. We know it can't be a gang block, so there's
* nothing to do except metaslab_free() it.
*/
void
zio_free_blk(spa_t *spa, blkptr_t *bp, uint64_t txg)
{
ASSERT(!BP_IS_GANG(bp));
metaslab_free(spa, bp, txg, B_FALSE);
}
/*
* ==========================================================================
* Read and write to physical devices
* ==========================================================================
*/
static int
zio_vdev_io_start(zio_t *zio)
{
vdev_t *vd = zio->io_vd;
uint64_t align;
spa_t *spa = zio->io_spa;
ASSERT(zio->io_error == 0);
ASSERT(zio->io_child_error[ZIO_CHILD_VDEV] == 0);
if (vd == NULL) {
if (!(zio->io_flags & ZIO_FLAG_CONFIG_WRITER))
spa_config_enter(spa, SCL_ZIO, zio, RW_READER);
/*
* The mirror_ops handle multiple DVAs in a single BP.
*/
return (vdev_mirror_ops.vdev_op_io_start(zio));
}
align = 1ULL << vd->vdev_top->vdev_ashift;
if (P2PHASE(zio->io_size, align) != 0) {
uint64_t asize = P2ROUNDUP(zio->io_size, align);
char *abuf = zio_buf_alloc(asize);
ASSERT(vd == vd->vdev_top);
if (zio->io_type == ZIO_TYPE_WRITE) {
bcopy(zio->io_data, abuf, zio->io_size);
bzero(abuf + zio->io_size, asize - zio->io_size);
}
zio_push_transform(zio, abuf, asize, asize, zio_subblock);
}
ASSERT(P2PHASE(zio->io_offset, align) == 0);
ASSERT(P2PHASE(zio->io_size, align) == 0);
ASSERT(zio->io_type != ZIO_TYPE_WRITE || spa_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);
}
static int
zio_vdev_io_assess(zio_t *zio)
{
vdev_t *vd = zio->io_vd;
if (zio_wait_for_children(zio, ZIO_CHILD_VDEV, ZIO_WAIT_DONE))
return (ZIO_PIPELINE_STOP);
if (vd == NULL && !(zio->io_flags & ZIO_FLAG_CONFIG_WRITER))
spa_config_exit(zio->io_spa, SCL_ZIO, zio);
if (zio->io_vsd != NULL) {
zio->io_vsd_free(zio);
zio->io_vsd = NULL;
}
if (zio_injection_enabled && zio->io_error == 0)
zio->io_error = zio_handle_fault_injection(zio, EIO);
/*
* If the I/O failed, determine whether we should attempt to retry it.
*/
if (zio->io_error && vd == NULL &&
!(zio->io_flags & (ZIO_FLAG_DONT_RETRY | ZIO_FLAG_IO_RETRY))) {
ASSERT(!(zio->io_flags & ZIO_FLAG_DONT_QUEUE)); /* not a leaf */
ASSERT(!(zio->io_flags & ZIO_FLAG_IO_BYPASS)); /* not a leaf */
zio->io_error = 0;
zio->io_flags |= ZIO_FLAG_IO_RETRY |
ZIO_FLAG_DONT_CACHE | ZIO_FLAG_DONT_AGGREGATE;
zio->io_stage = ZIO_STAGE_VDEV_IO_START - 1;
zio_taskq_dispatch(zio, ZIO_TASKQ_ISSUE);
return (ZIO_PIPELINE_STOP);
}
/*
* If we got an error on a leaf device, convert it to ENXIO
* if the device is not accessible at all.
*/
if (zio->io_error && vd != NULL && vd->vdev_ops->vdev_op_leaf &&
!vdev_accessible(vd, zio))
zio->io_error = ENXIO;
/*
* If we can't write to an interior vdev (mirror or RAID-Z),
* set vdev_cant_write so that we stop trying to allocate from it.
*/
if (zio->io_error == ENXIO && zio->io_type == ZIO_TYPE_WRITE &&
vd != NULL && !vd->vdev_ops->vdev_op_leaf)
vd->vdev_cant_write = B_TRUE;
if (zio->io_error)
zio->io_pipeline = ZIO_INTERLOCK_PIPELINE;
return (ZIO_PIPELINE_CONTINUE);
}
void
zio_vdev_io_reissue(zio_t *zio)
{
ASSERT(zio->io_stage == ZIO_STAGE_VDEV_IO_START);
ASSERT(zio->io_error == 0);
zio->io_stage--;
}
void
zio_vdev_io_redone(zio_t *zio)
{
ASSERT(zio->io_stage == ZIO_STAGE_VDEV_IO_DONE);
zio->io_stage--;
}
void
zio_vdev_io_bypass(zio_t *zio)
{
ASSERT(zio->io_stage == ZIO_STAGE_VDEV_IO_START);
ASSERT(zio->io_error == 0);
zio->io_flags |= ZIO_FLAG_IO_BYPASS;
zio->io_stage = ZIO_STAGE_VDEV_IO_ASSESS - 1;
}
/*
* ==========================================================================
* Generate and verify checksums
* ==========================================================================
*/
static int
zio_checksum_generate(zio_t *zio)
{
blkptr_t *bp = zio->io_bp;
enum zio_checksum checksum;
if (bp == NULL) {
/*
* This is zio_write_phys().
* We're either generating a label checksum, or none at all.
*/
checksum = zio->io_prop.zp_checksum;
if (checksum == ZIO_CHECKSUM_OFF)
return (ZIO_PIPELINE_CONTINUE);
ASSERT(checksum == ZIO_CHECKSUM_LABEL);
} else {
if (BP_IS_GANG(bp) && zio->io_child_type == ZIO_CHILD_GANG) {
ASSERT(!IO_IS_ALLOCATING(zio));
checksum = ZIO_CHECKSUM_GANG_HEADER;
} else {
checksum = BP_GET_CHECKSUM(bp);
}
}
zio_checksum_compute(zio, checksum, zio->io_data, zio->io_size);
return (ZIO_PIPELINE_CONTINUE);
}
static int
zio_checksum_verify(zio_t *zio)
{
blkptr_t *bp = zio->io_bp;
int error;
if (bp == NULL) {
/*
* This is zio_read_phys().
* We're either verifying a label checksum, or nothing at all.
*/
if (zio->io_prop.zp_checksum == ZIO_CHECKSUM_OFF)
return (ZIO_PIPELINE_CONTINUE);
ASSERT(zio->io_prop.zp_checksum == ZIO_CHECKSUM_LABEL);
}
if ((error = zio_checksum_error(zio)) != 0) {
zio->io_error = error;
if (!(zio->io_flags & ZIO_FLAG_SPECULATIVE)) {
zfs_ereport_post(FM_EREPORT_ZFS_CHECKSUM,
zio->io_spa, zio->io_vd, zio, 0, 0);
}
}
return (ZIO_PIPELINE_CONTINUE);
}
/*
* Called by RAID-Z to ensure we don't compute the checksum twice.
*/
void
zio_checksum_verified(zio_t *zio)
{
zio->io_pipeline &= ~(1U << ZIO_STAGE_CHECKSUM_VERIFY);
}
/*
* ==========================================================================
* Error rank. Error are ranked in the order 0, ENXIO, ECKSUM, EIO, other.
* An error of 0 indictes success. ENXIO indicates whole-device failure,
* which may be transient (e.g. unplugged) or permament. ECKSUM and EIO
* indicate errors that are specific to one I/O, and most likely permanent.
* Any other error is presumed to be worse because we weren't expecting it.
* ==========================================================================
*/
int
zio_worst_error(int e1, int e2)
{
static int zio_error_rank[] = { 0, ENXIO, ECKSUM, EIO };
int r1, r2;
for (r1 = 0; r1 < sizeof (zio_error_rank) / sizeof (int); r1++)
if (e1 == zio_error_rank[r1])
break;
for (r2 = 0; r2 < sizeof (zio_error_rank) / sizeof (int); r2++)
if (e2 == zio_error_rank[r2])
break;
return (r1 > r2 ? e1 : e2);
}
/*
* ==========================================================================
* I/O completion
* ==========================================================================
*/
static int
zio_ready(zio_t *zio)
{
blkptr_t *bp = zio->io_bp;
zio_t *pio, *pio_next;
if (zio_wait_for_children(zio, ZIO_CHILD_GANG, 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);
}
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;
int c, w;
/*
* 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_LOGICAL, ZIO_WAIT_DONE))
return (ZIO_PIPELINE_STOP);
for (c = 0; c < ZIO_CHILD_TYPES; c++)
for (w = 0; w < ZIO_WAIT_TYPES; w++)
ASSERT(zio->io_children[c][w] == 0);
if (bp != NULL) {
ASSERT(bp->blk_pad[0] == 0);
ASSERT(bp->blk_pad[1] == 0);
ASSERT(bp->blk_pad[2] == 0);
ASSERT(bcmp(bp, &zio->io_bp_copy, sizeof (blkptr_t)) == 0 ||
(bp == zio_unique_parent(zio)->io_bp));
if (zio->io_type == ZIO_TYPE_WRITE && !BP_IS_HOLE(bp) &&
!(zio->io_flags & ZIO_FLAG_IO_REPAIR)) {
ASSERT(!BP_SHOULD_BYTESWAP(bp));
ASSERT3U(zio->io_prop.zp_ndvas, <=, BP_GET_NDVAS(bp));
ASSERT(BP_COUNT_GANG(bp) == 0 ||
(BP_COUNT_GANG(bp) == BP_GET_NDVAS(bp)));
}
}
/*
* If there were child vdev or gang errors, they apply to us now.
*/
zio_inherit_child_errors(zio, ZIO_CHILD_VDEV);
zio_inherit_child_errors(zio, ZIO_CHILD_GANG);
zio_pop_transforms(zio); /* note: may set zio->io_error */
vdev_stat_update(zio, psize);
if (zio->io_error) {
/*
* If this I/O is attached to a particular vdev,
* generate an error message describing the I/O failure
* at the block level. We ignore these errors if the
* device is currently unavailable.
*/
if (zio->io_error != ECKSUM && vd != NULL && !vdev_is_dead(vd))
zfs_ereport_post(FM_EREPORT_ZFS_IO, spa, vd, zio, 0, 0);
if ((zio->io_error == EIO ||
!(zio->io_flags & ZIO_FLAG_SPECULATIVE)) && zio == lio) {
/*
* For logical I/O requests, tell the SPA to log the
* error and generate a logical data ereport.
*/
spa_log_error(spa, zio);
zfs_ereport_post(FM_EREPORT_ZFS_DATA, spa, NULL, zio,
0, 0);
}
}
if (zio->io_error && zio == lio) {
/*
* Determine whether zio should be reexecuted. This will
* propagate all the way to the root via zio_notify_parent().
*/
ASSERT(vd == NULL && bp != NULL);
if (IO_IS_ALLOCATING(zio)) {
if (zio->io_error != ENOSPC)
zio->io_reexecute |= ZIO_REEXECUTE_NOW;
else
zio->io_reexecute |= ZIO_REEXECUTE_SUSPEND;
}
if ((zio->io_type == ZIO_TYPE_READ ||
zio->io_type == ZIO_TYPE_FREE) &&
zio->io_error == ENXIO &&
spa->spa_load_state == 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;
}
/*
* 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_child_type == ZIO_CHILD_LOGICAL) {
ASSERT(zio->io_child_type != ZIO_CHILD_GANG);
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_walk_children(zio) == NULL);
ASSERT(zio->io_reexecute == 0);
ASSERT(zio->io_error == 0 || (zio->io_flags & ZIO_FLAG_CANFAIL));
/*
* 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[ZIO_STAGES] = {
NULL,
zio_issue_async,
zio_read_bp_init,
zio_write_bp_init,
zio_checksum_generate,
zio_gang_assemble,
zio_gang_issue,
zio_dva_allocate,
zio_dva_free,
zio_dva_claim,
zio_ready,
zio_vdev_io_start,
zio_vdev_io_done,
zio_vdev_io_assess,
zio_checksum_verify,
zio_done
};
#if defined(_KERNEL) && defined(HAVE_SPL)
/* Fault injection */
EXPORT_SYMBOL(zio_injection_enabled);
EXPORT_SYMBOL(zio_inject_fault);
EXPORT_SYMBOL(zio_inject_list_next);
EXPORT_SYMBOL(zio_clear_fault);
EXPORT_SYMBOL(zio_handle_fault_injection);
EXPORT_SYMBOL(zio_handle_device_injection);
EXPORT_SYMBOL(zio_handle_label_injection);
EXPORT_SYMBOL(zio_priority_table);
EXPORT_SYMBOL(zio_type_name);
module_param(zio_bulk_flags, int, 0644);
MODULE_PARM_DESC(zio_bulk_flags, "Additional flags to pass to bulk buffers");
#endif
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