d73415a315
clang's C11 atomic_fetch_*() functions only take a C11 atomic type
pointer argument. QEMU uses direct types (int, etc) and this causes a
compiler error when a QEMU code calls these functions in a source file
that also included <stdatomic.h> via a system header file:
$ CC=clang CXX=clang++ ./configure ... && make
../util/async.c:79:17: error: address argument to atomic operation must be a pointer to _Atomic type ('unsigned int *' invalid)
Avoid using atomic_*() names in QEMU's atomic.h since that namespace is
used by <stdatomic.h>. Prefix QEMU's APIs with 'q' so that atomic.h
and <stdatomic.h> can co-exist. I checked /usr/include on my machine and
searched GitHub for existing "qatomic_" users but there seem to be none.
This patch was generated using:
$ git grep -h -o '\<atomic\(64\)\?_[a-z0-9_]\+' include/qemu/atomic.h | \
sort -u >/tmp/changed_identifiers
$ for identifier in $(</tmp/changed_identifiers); do
sed -i "s%\<$identifier\>%q$identifier%g" \
$(git grep -I -l "\<$identifier\>")
done
I manually fixed line-wrap issues and misaligned rST tables.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <20200923105646.47864-1-stefanha@redhat.com>
3455 lines
104 KiB
C
3455 lines
104 KiB
C
/*
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* Block layer I/O functions
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*
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* Copyright (c) 2003 Fabrice Bellard
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to deal
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* in the Software without restriction, including without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
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* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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* THE SOFTWARE.
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*/
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#include "qemu/osdep.h"
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#include "trace.h"
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#include "sysemu/block-backend.h"
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#include "block/aio-wait.h"
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#include "block/blockjob.h"
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#include "block/blockjob_int.h"
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#include "block/block_int.h"
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#include "qemu/cutils.h"
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#include "qapi/error.h"
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#include "qemu/error-report.h"
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#include "qemu/main-loop.h"
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#include "sysemu/replay.h"
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/* Maximum bounce buffer for copy-on-read and write zeroes, in bytes */
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#define MAX_BOUNCE_BUFFER (32768 << BDRV_SECTOR_BITS)
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static void bdrv_parent_cb_resize(BlockDriverState *bs);
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static int coroutine_fn bdrv_co_do_pwrite_zeroes(BlockDriverState *bs,
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int64_t offset, int bytes, BdrvRequestFlags flags);
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static void bdrv_parent_drained_begin(BlockDriverState *bs, BdrvChild *ignore,
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bool ignore_bds_parents)
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{
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BdrvChild *c, *next;
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QLIST_FOREACH_SAFE(c, &bs->parents, next_parent, next) {
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if (c == ignore || (ignore_bds_parents && c->klass->parent_is_bds)) {
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continue;
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}
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bdrv_parent_drained_begin_single(c, false);
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}
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}
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static void bdrv_parent_drained_end_single_no_poll(BdrvChild *c,
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int *drained_end_counter)
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{
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assert(c->parent_quiesce_counter > 0);
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c->parent_quiesce_counter--;
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if (c->klass->drained_end) {
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c->klass->drained_end(c, drained_end_counter);
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}
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}
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void bdrv_parent_drained_end_single(BdrvChild *c)
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{
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int drained_end_counter = 0;
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bdrv_parent_drained_end_single_no_poll(c, &drained_end_counter);
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BDRV_POLL_WHILE(c->bs, qatomic_read(&drained_end_counter) > 0);
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}
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static void bdrv_parent_drained_end(BlockDriverState *bs, BdrvChild *ignore,
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bool ignore_bds_parents,
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int *drained_end_counter)
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{
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BdrvChild *c;
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QLIST_FOREACH(c, &bs->parents, next_parent) {
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if (c == ignore || (ignore_bds_parents && c->klass->parent_is_bds)) {
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continue;
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}
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bdrv_parent_drained_end_single_no_poll(c, drained_end_counter);
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}
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}
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static bool bdrv_parent_drained_poll_single(BdrvChild *c)
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{
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if (c->klass->drained_poll) {
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return c->klass->drained_poll(c);
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}
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return false;
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}
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static bool bdrv_parent_drained_poll(BlockDriverState *bs, BdrvChild *ignore,
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bool ignore_bds_parents)
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{
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BdrvChild *c, *next;
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bool busy = false;
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QLIST_FOREACH_SAFE(c, &bs->parents, next_parent, next) {
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if (c == ignore || (ignore_bds_parents && c->klass->parent_is_bds)) {
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continue;
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}
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busy |= bdrv_parent_drained_poll_single(c);
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}
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return busy;
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}
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void bdrv_parent_drained_begin_single(BdrvChild *c, bool poll)
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{
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c->parent_quiesce_counter++;
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if (c->klass->drained_begin) {
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c->klass->drained_begin(c);
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}
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if (poll) {
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BDRV_POLL_WHILE(c->bs, bdrv_parent_drained_poll_single(c));
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}
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}
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static void bdrv_merge_limits(BlockLimits *dst, const BlockLimits *src)
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{
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dst->opt_transfer = MAX(dst->opt_transfer, src->opt_transfer);
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dst->max_transfer = MIN_NON_ZERO(dst->max_transfer, src->max_transfer);
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dst->opt_mem_alignment = MAX(dst->opt_mem_alignment,
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src->opt_mem_alignment);
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dst->min_mem_alignment = MAX(dst->min_mem_alignment,
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src->min_mem_alignment);
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dst->max_iov = MIN_NON_ZERO(dst->max_iov, src->max_iov);
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}
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void bdrv_refresh_limits(BlockDriverState *bs, Error **errp)
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{
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BlockDriver *drv = bs->drv;
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BdrvChild *c;
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bool have_limits;
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Error *local_err = NULL;
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memset(&bs->bl, 0, sizeof(bs->bl));
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if (!drv) {
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return;
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}
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/* Default alignment based on whether driver has byte interface */
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bs->bl.request_alignment = (drv->bdrv_co_preadv ||
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drv->bdrv_aio_preadv ||
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drv->bdrv_co_preadv_part) ? 1 : 512;
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/* Take some limits from the children as a default */
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have_limits = false;
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QLIST_FOREACH(c, &bs->children, next) {
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if (c->role & (BDRV_CHILD_DATA | BDRV_CHILD_FILTERED | BDRV_CHILD_COW))
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{
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bdrv_refresh_limits(c->bs, &local_err);
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if (local_err) {
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error_propagate(errp, local_err);
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return;
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}
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bdrv_merge_limits(&bs->bl, &c->bs->bl);
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have_limits = true;
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}
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}
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if (!have_limits) {
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bs->bl.min_mem_alignment = 512;
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bs->bl.opt_mem_alignment = qemu_real_host_page_size;
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/* Safe default since most protocols use readv()/writev()/etc */
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bs->bl.max_iov = IOV_MAX;
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}
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/* Then let the driver override it */
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if (drv->bdrv_refresh_limits) {
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drv->bdrv_refresh_limits(bs, errp);
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}
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}
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/**
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* The copy-on-read flag is actually a reference count so multiple users may
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* use the feature without worrying about clobbering its previous state.
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* Copy-on-read stays enabled until all users have called to disable it.
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*/
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void bdrv_enable_copy_on_read(BlockDriverState *bs)
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{
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qatomic_inc(&bs->copy_on_read);
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}
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void bdrv_disable_copy_on_read(BlockDriverState *bs)
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{
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int old = qatomic_fetch_dec(&bs->copy_on_read);
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assert(old >= 1);
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}
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typedef struct {
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Coroutine *co;
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BlockDriverState *bs;
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bool done;
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bool begin;
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bool recursive;
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bool poll;
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BdrvChild *parent;
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bool ignore_bds_parents;
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int *drained_end_counter;
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} BdrvCoDrainData;
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static void coroutine_fn bdrv_drain_invoke_entry(void *opaque)
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{
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BdrvCoDrainData *data = opaque;
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BlockDriverState *bs = data->bs;
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if (data->begin) {
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bs->drv->bdrv_co_drain_begin(bs);
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} else {
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bs->drv->bdrv_co_drain_end(bs);
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}
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/* Set data->done and decrement drained_end_counter before bdrv_wakeup() */
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qatomic_mb_set(&data->done, true);
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if (!data->begin) {
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qatomic_dec(data->drained_end_counter);
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}
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bdrv_dec_in_flight(bs);
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g_free(data);
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}
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/* Recursively call BlockDriver.bdrv_co_drain_begin/end callbacks */
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static void bdrv_drain_invoke(BlockDriverState *bs, bool begin,
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int *drained_end_counter)
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{
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BdrvCoDrainData *data;
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if (!bs->drv || (begin && !bs->drv->bdrv_co_drain_begin) ||
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(!begin && !bs->drv->bdrv_co_drain_end)) {
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return;
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}
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data = g_new(BdrvCoDrainData, 1);
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*data = (BdrvCoDrainData) {
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.bs = bs,
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.done = false,
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.begin = begin,
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.drained_end_counter = drained_end_counter,
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};
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if (!begin) {
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qatomic_inc(drained_end_counter);
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}
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/* Make sure the driver callback completes during the polling phase for
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* drain_begin. */
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bdrv_inc_in_flight(bs);
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data->co = qemu_coroutine_create(bdrv_drain_invoke_entry, data);
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aio_co_schedule(bdrv_get_aio_context(bs), data->co);
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}
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/* Returns true if BDRV_POLL_WHILE() should go into a blocking aio_poll() */
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bool bdrv_drain_poll(BlockDriverState *bs, bool recursive,
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BdrvChild *ignore_parent, bool ignore_bds_parents)
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{
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BdrvChild *child, *next;
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if (bdrv_parent_drained_poll(bs, ignore_parent, ignore_bds_parents)) {
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return true;
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}
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if (qatomic_read(&bs->in_flight)) {
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return true;
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}
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if (recursive) {
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assert(!ignore_bds_parents);
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QLIST_FOREACH_SAFE(child, &bs->children, next, next) {
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if (bdrv_drain_poll(child->bs, recursive, child, false)) {
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return true;
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}
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}
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}
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return false;
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}
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static bool bdrv_drain_poll_top_level(BlockDriverState *bs, bool recursive,
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BdrvChild *ignore_parent)
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{
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return bdrv_drain_poll(bs, recursive, ignore_parent, false);
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}
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static void bdrv_do_drained_begin(BlockDriverState *bs, bool recursive,
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BdrvChild *parent, bool ignore_bds_parents,
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bool poll);
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static void bdrv_do_drained_end(BlockDriverState *bs, bool recursive,
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BdrvChild *parent, bool ignore_bds_parents,
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int *drained_end_counter);
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static void bdrv_co_drain_bh_cb(void *opaque)
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{
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BdrvCoDrainData *data = opaque;
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Coroutine *co = data->co;
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BlockDriverState *bs = data->bs;
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if (bs) {
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AioContext *ctx = bdrv_get_aio_context(bs);
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AioContext *co_ctx = qemu_coroutine_get_aio_context(co);
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/*
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* When the coroutine yielded, the lock for its home context was
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* released, so we need to re-acquire it here. If it explicitly
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* acquired a different context, the lock is still held and we don't
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* want to lock it a second time (or AIO_WAIT_WHILE() would hang).
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*/
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if (ctx == co_ctx) {
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aio_context_acquire(ctx);
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}
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bdrv_dec_in_flight(bs);
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if (data->begin) {
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assert(!data->drained_end_counter);
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bdrv_do_drained_begin(bs, data->recursive, data->parent,
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data->ignore_bds_parents, data->poll);
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} else {
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assert(!data->poll);
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bdrv_do_drained_end(bs, data->recursive, data->parent,
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data->ignore_bds_parents,
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data->drained_end_counter);
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}
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if (ctx == co_ctx) {
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aio_context_release(ctx);
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}
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} else {
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assert(data->begin);
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bdrv_drain_all_begin();
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}
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data->done = true;
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aio_co_wake(co);
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}
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static void coroutine_fn bdrv_co_yield_to_drain(BlockDriverState *bs,
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bool begin, bool recursive,
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BdrvChild *parent,
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bool ignore_bds_parents,
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bool poll,
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int *drained_end_counter)
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{
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BdrvCoDrainData data;
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/* Calling bdrv_drain() from a BH ensures the current coroutine yields and
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* other coroutines run if they were queued by aio_co_enter(). */
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assert(qemu_in_coroutine());
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data = (BdrvCoDrainData) {
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.co = qemu_coroutine_self(),
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.bs = bs,
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.done = false,
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.begin = begin,
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.recursive = recursive,
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.parent = parent,
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.ignore_bds_parents = ignore_bds_parents,
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.poll = poll,
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.drained_end_counter = drained_end_counter,
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};
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if (bs) {
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bdrv_inc_in_flight(bs);
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}
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replay_bh_schedule_oneshot_event(bdrv_get_aio_context(bs),
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bdrv_co_drain_bh_cb, &data);
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qemu_coroutine_yield();
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/* If we are resumed from some other event (such as an aio completion or a
|
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* timer callback), it is a bug in the caller that should be fixed. */
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assert(data.done);
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}
|
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|
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void bdrv_do_drained_begin_quiesce(BlockDriverState *bs,
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BdrvChild *parent, bool ignore_bds_parents)
|
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{
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assert(!qemu_in_coroutine());
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|
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/* Stop things in parent-to-child order */
|
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if (qatomic_fetch_inc(&bs->quiesce_counter) == 0) {
|
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aio_disable_external(bdrv_get_aio_context(bs));
|
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}
|
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|
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bdrv_parent_drained_begin(bs, parent, ignore_bds_parents);
|
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bdrv_drain_invoke(bs, true, NULL);
|
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}
|
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|
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static void bdrv_do_drained_begin(BlockDriverState *bs, bool recursive,
|
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BdrvChild *parent, bool ignore_bds_parents,
|
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bool poll)
|
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{
|
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BdrvChild *child, *next;
|
|
|
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if (qemu_in_coroutine()) {
|
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bdrv_co_yield_to_drain(bs, true, recursive, parent, ignore_bds_parents,
|
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poll, NULL);
|
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return;
|
|
}
|
|
|
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bdrv_do_drained_begin_quiesce(bs, parent, ignore_bds_parents);
|
|
|
|
if (recursive) {
|
|
assert(!ignore_bds_parents);
|
|
bs->recursive_quiesce_counter++;
|
|
QLIST_FOREACH_SAFE(child, &bs->children, next, next) {
|
|
bdrv_do_drained_begin(child->bs, true, child, ignore_bds_parents,
|
|
false);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Wait for drained requests to finish.
|
|
*
|
|
* Calling BDRV_POLL_WHILE() only once for the top-level node is okay: The
|
|
* call is needed so things in this AioContext can make progress even
|
|
* though we don't return to the main AioContext loop - this automatically
|
|
* includes other nodes in the same AioContext and therefore all child
|
|
* nodes.
|
|
*/
|
|
if (poll) {
|
|
assert(!ignore_bds_parents);
|
|
BDRV_POLL_WHILE(bs, bdrv_drain_poll_top_level(bs, recursive, parent));
|
|
}
|
|
}
|
|
|
|
void bdrv_drained_begin(BlockDriverState *bs)
|
|
{
|
|
bdrv_do_drained_begin(bs, false, NULL, false, true);
|
|
}
|
|
|
|
void bdrv_subtree_drained_begin(BlockDriverState *bs)
|
|
{
|
|
bdrv_do_drained_begin(bs, true, NULL, false, true);
|
|
}
|
|
|
|
/**
|
|
* This function does not poll, nor must any of its recursively called
|
|
* functions. The *drained_end_counter pointee will be incremented
|
|
* once for every background operation scheduled, and decremented once
|
|
* the operation settles. Therefore, the pointer must remain valid
|
|
* until the pointee reaches 0. That implies that whoever sets up the
|
|
* pointee has to poll until it is 0.
|
|
*
|
|
* We use atomic operations to access *drained_end_counter, because
|
|
* (1) when called from bdrv_set_aio_context_ignore(), the subgraph of
|
|
* @bs may contain nodes in different AioContexts,
|
|
* (2) bdrv_drain_all_end() uses the same counter for all nodes,
|
|
* regardless of which AioContext they are in.
|
|
*/
|
|
static void bdrv_do_drained_end(BlockDriverState *bs, bool recursive,
|
|
BdrvChild *parent, bool ignore_bds_parents,
|
|
int *drained_end_counter)
|
|
{
|
|
BdrvChild *child;
|
|
int old_quiesce_counter;
|
|
|
|
assert(drained_end_counter != NULL);
|
|
|
|
if (qemu_in_coroutine()) {
|
|
bdrv_co_yield_to_drain(bs, false, recursive, parent, ignore_bds_parents,
|
|
false, drained_end_counter);
|
|
return;
|
|
}
|
|
assert(bs->quiesce_counter > 0);
|
|
|
|
/* Re-enable things in child-to-parent order */
|
|
bdrv_drain_invoke(bs, false, drained_end_counter);
|
|
bdrv_parent_drained_end(bs, parent, ignore_bds_parents,
|
|
drained_end_counter);
|
|
|
|
old_quiesce_counter = qatomic_fetch_dec(&bs->quiesce_counter);
|
|
if (old_quiesce_counter == 1) {
|
|
aio_enable_external(bdrv_get_aio_context(bs));
|
|
}
|
|
|
|
if (recursive) {
|
|
assert(!ignore_bds_parents);
|
|
bs->recursive_quiesce_counter--;
|
|
QLIST_FOREACH(child, &bs->children, next) {
|
|
bdrv_do_drained_end(child->bs, true, child, ignore_bds_parents,
|
|
drained_end_counter);
|
|
}
|
|
}
|
|
}
|
|
|
|
void bdrv_drained_end(BlockDriverState *bs)
|
|
{
|
|
int drained_end_counter = 0;
|
|
bdrv_do_drained_end(bs, false, NULL, false, &drained_end_counter);
|
|
BDRV_POLL_WHILE(bs, qatomic_read(&drained_end_counter) > 0);
|
|
}
|
|
|
|
void bdrv_drained_end_no_poll(BlockDriverState *bs, int *drained_end_counter)
|
|
{
|
|
bdrv_do_drained_end(bs, false, NULL, false, drained_end_counter);
|
|
}
|
|
|
|
void bdrv_subtree_drained_end(BlockDriverState *bs)
|
|
{
|
|
int drained_end_counter = 0;
|
|
bdrv_do_drained_end(bs, true, NULL, false, &drained_end_counter);
|
|
BDRV_POLL_WHILE(bs, qatomic_read(&drained_end_counter) > 0);
|
|
}
|
|
|
|
void bdrv_apply_subtree_drain(BdrvChild *child, BlockDriverState *new_parent)
|
|
{
|
|
int i;
|
|
|
|
for (i = 0; i < new_parent->recursive_quiesce_counter; i++) {
|
|
bdrv_do_drained_begin(child->bs, true, child, false, true);
|
|
}
|
|
}
|
|
|
|
void bdrv_unapply_subtree_drain(BdrvChild *child, BlockDriverState *old_parent)
|
|
{
|
|
int drained_end_counter = 0;
|
|
int i;
|
|
|
|
for (i = 0; i < old_parent->recursive_quiesce_counter; i++) {
|
|
bdrv_do_drained_end(child->bs, true, child, false,
|
|
&drained_end_counter);
|
|
}
|
|
|
|
BDRV_POLL_WHILE(child->bs, qatomic_read(&drained_end_counter) > 0);
|
|
}
|
|
|
|
/*
|
|
* Wait for pending requests to complete on a single BlockDriverState subtree,
|
|
* and suspend block driver's internal I/O until next request arrives.
|
|
*
|
|
* Note that unlike bdrv_drain_all(), the caller must hold the BlockDriverState
|
|
* AioContext.
|
|
*/
|
|
void coroutine_fn bdrv_co_drain(BlockDriverState *bs)
|
|
{
|
|
assert(qemu_in_coroutine());
|
|
bdrv_drained_begin(bs);
|
|
bdrv_drained_end(bs);
|
|
}
|
|
|
|
void bdrv_drain(BlockDriverState *bs)
|
|
{
|
|
bdrv_drained_begin(bs);
|
|
bdrv_drained_end(bs);
|
|
}
|
|
|
|
static void bdrv_drain_assert_idle(BlockDriverState *bs)
|
|
{
|
|
BdrvChild *child, *next;
|
|
|
|
assert(qatomic_read(&bs->in_flight) == 0);
|
|
QLIST_FOREACH_SAFE(child, &bs->children, next, next) {
|
|
bdrv_drain_assert_idle(child->bs);
|
|
}
|
|
}
|
|
|
|
unsigned int bdrv_drain_all_count = 0;
|
|
|
|
static bool bdrv_drain_all_poll(void)
|
|
{
|
|
BlockDriverState *bs = NULL;
|
|
bool result = false;
|
|
|
|
/* bdrv_drain_poll() can't make changes to the graph and we are holding the
|
|
* main AioContext lock, so iterating bdrv_next_all_states() is safe. */
|
|
while ((bs = bdrv_next_all_states(bs))) {
|
|
AioContext *aio_context = bdrv_get_aio_context(bs);
|
|
aio_context_acquire(aio_context);
|
|
result |= bdrv_drain_poll(bs, false, NULL, true);
|
|
aio_context_release(aio_context);
|
|
}
|
|
|
|
return result;
|
|
}
|
|
|
|
/*
|
|
* Wait for pending requests to complete across all BlockDriverStates
|
|
*
|
|
* This function does not flush data to disk, use bdrv_flush_all() for that
|
|
* after calling this function.
|
|
*
|
|
* This pauses all block jobs and disables external clients. It must
|
|
* be paired with bdrv_drain_all_end().
|
|
*
|
|
* NOTE: no new block jobs or BlockDriverStates can be created between
|
|
* the bdrv_drain_all_begin() and bdrv_drain_all_end() calls.
|
|
*/
|
|
void bdrv_drain_all_begin(void)
|
|
{
|
|
BlockDriverState *bs = NULL;
|
|
|
|
if (qemu_in_coroutine()) {
|
|
bdrv_co_yield_to_drain(NULL, true, false, NULL, true, true, NULL);
|
|
return;
|
|
}
|
|
|
|
/*
|
|
* bdrv queue is managed by record/replay,
|
|
* waiting for finishing the I/O requests may
|
|
* be infinite
|
|
*/
|
|
if (replay_events_enabled()) {
|
|
return;
|
|
}
|
|
|
|
/* AIO_WAIT_WHILE() with a NULL context can only be called from the main
|
|
* loop AioContext, so make sure we're in the main context. */
|
|
assert(qemu_get_current_aio_context() == qemu_get_aio_context());
|
|
assert(bdrv_drain_all_count < INT_MAX);
|
|
bdrv_drain_all_count++;
|
|
|
|
/* Quiesce all nodes, without polling in-flight requests yet. The graph
|
|
* cannot change during this loop. */
|
|
while ((bs = bdrv_next_all_states(bs))) {
|
|
AioContext *aio_context = bdrv_get_aio_context(bs);
|
|
|
|
aio_context_acquire(aio_context);
|
|
bdrv_do_drained_begin(bs, false, NULL, true, false);
|
|
aio_context_release(aio_context);
|
|
}
|
|
|
|
/* Now poll the in-flight requests */
|
|
AIO_WAIT_WHILE(NULL, bdrv_drain_all_poll());
|
|
|
|
while ((bs = bdrv_next_all_states(bs))) {
|
|
bdrv_drain_assert_idle(bs);
|
|
}
|
|
}
|
|
|
|
void bdrv_drain_all_end(void)
|
|
{
|
|
BlockDriverState *bs = NULL;
|
|
int drained_end_counter = 0;
|
|
|
|
/*
|
|
* bdrv queue is managed by record/replay,
|
|
* waiting for finishing the I/O requests may
|
|
* be endless
|
|
*/
|
|
if (replay_events_enabled()) {
|
|
return;
|
|
}
|
|
|
|
while ((bs = bdrv_next_all_states(bs))) {
|
|
AioContext *aio_context = bdrv_get_aio_context(bs);
|
|
|
|
aio_context_acquire(aio_context);
|
|
bdrv_do_drained_end(bs, false, NULL, true, &drained_end_counter);
|
|
aio_context_release(aio_context);
|
|
}
|
|
|
|
assert(qemu_get_current_aio_context() == qemu_get_aio_context());
|
|
AIO_WAIT_WHILE(NULL, qatomic_read(&drained_end_counter) > 0);
|
|
|
|
assert(bdrv_drain_all_count > 0);
|
|
bdrv_drain_all_count--;
|
|
}
|
|
|
|
void bdrv_drain_all(void)
|
|
{
|
|
bdrv_drain_all_begin();
|
|
bdrv_drain_all_end();
|
|
}
|
|
|
|
/**
|
|
* Remove an active request from the tracked requests list
|
|
*
|
|
* This function should be called when a tracked request is completing.
|
|
*/
|
|
static void tracked_request_end(BdrvTrackedRequest *req)
|
|
{
|
|
if (req->serialising) {
|
|
qatomic_dec(&req->bs->serialising_in_flight);
|
|
}
|
|
|
|
qemu_co_mutex_lock(&req->bs->reqs_lock);
|
|
QLIST_REMOVE(req, list);
|
|
qemu_co_queue_restart_all(&req->wait_queue);
|
|
qemu_co_mutex_unlock(&req->bs->reqs_lock);
|
|
}
|
|
|
|
/**
|
|
* Add an active request to the tracked requests list
|
|
*/
|
|
static void tracked_request_begin(BdrvTrackedRequest *req,
|
|
BlockDriverState *bs,
|
|
int64_t offset,
|
|
uint64_t bytes,
|
|
enum BdrvTrackedRequestType type)
|
|
{
|
|
assert(bytes <= INT64_MAX && offset <= INT64_MAX - bytes);
|
|
|
|
*req = (BdrvTrackedRequest){
|
|
.bs = bs,
|
|
.offset = offset,
|
|
.bytes = bytes,
|
|
.type = type,
|
|
.co = qemu_coroutine_self(),
|
|
.serialising = false,
|
|
.overlap_offset = offset,
|
|
.overlap_bytes = bytes,
|
|
};
|
|
|
|
qemu_co_queue_init(&req->wait_queue);
|
|
|
|
qemu_co_mutex_lock(&bs->reqs_lock);
|
|
QLIST_INSERT_HEAD(&bs->tracked_requests, req, list);
|
|
qemu_co_mutex_unlock(&bs->reqs_lock);
|
|
}
|
|
|
|
static bool tracked_request_overlaps(BdrvTrackedRequest *req,
|
|
int64_t offset, uint64_t bytes)
|
|
{
|
|
/* aaaa bbbb */
|
|
if (offset >= req->overlap_offset + req->overlap_bytes) {
|
|
return false;
|
|
}
|
|
/* bbbb aaaa */
|
|
if (req->overlap_offset >= offset + bytes) {
|
|
return false;
|
|
}
|
|
return true;
|
|
}
|
|
|
|
static bool coroutine_fn
|
|
bdrv_wait_serialising_requests_locked(BlockDriverState *bs,
|
|
BdrvTrackedRequest *self)
|
|
{
|
|
BdrvTrackedRequest *req;
|
|
bool retry;
|
|
bool waited = false;
|
|
|
|
do {
|
|
retry = false;
|
|
QLIST_FOREACH(req, &bs->tracked_requests, list) {
|
|
if (req == self || (!req->serialising && !self->serialising)) {
|
|
continue;
|
|
}
|
|
if (tracked_request_overlaps(req, self->overlap_offset,
|
|
self->overlap_bytes))
|
|
{
|
|
/* Hitting this means there was a reentrant request, for
|
|
* example, a block driver issuing nested requests. This must
|
|
* never happen since it means deadlock.
|
|
*/
|
|
assert(qemu_coroutine_self() != req->co);
|
|
|
|
/* If the request is already (indirectly) waiting for us, or
|
|
* will wait for us as soon as it wakes up, then just go on
|
|
* (instead of producing a deadlock in the former case). */
|
|
if (!req->waiting_for) {
|
|
self->waiting_for = req;
|
|
qemu_co_queue_wait(&req->wait_queue, &bs->reqs_lock);
|
|
self->waiting_for = NULL;
|
|
retry = true;
|
|
waited = true;
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
} while (retry);
|
|
return waited;
|
|
}
|
|
|
|
bool bdrv_mark_request_serialising(BdrvTrackedRequest *req, uint64_t align)
|
|
{
|
|
BlockDriverState *bs = req->bs;
|
|
int64_t overlap_offset = req->offset & ~(align - 1);
|
|
uint64_t overlap_bytes = ROUND_UP(req->offset + req->bytes, align)
|
|
- overlap_offset;
|
|
bool waited;
|
|
|
|
qemu_co_mutex_lock(&bs->reqs_lock);
|
|
if (!req->serialising) {
|
|
qatomic_inc(&req->bs->serialising_in_flight);
|
|
req->serialising = true;
|
|
}
|
|
|
|
req->overlap_offset = MIN(req->overlap_offset, overlap_offset);
|
|
req->overlap_bytes = MAX(req->overlap_bytes, overlap_bytes);
|
|
waited = bdrv_wait_serialising_requests_locked(bs, req);
|
|
qemu_co_mutex_unlock(&bs->reqs_lock);
|
|
return waited;
|
|
}
|
|
|
|
/**
|
|
* Return the tracked request on @bs for the current coroutine, or
|
|
* NULL if there is none.
|
|
*/
|
|
BdrvTrackedRequest *coroutine_fn bdrv_co_get_self_request(BlockDriverState *bs)
|
|
{
|
|
BdrvTrackedRequest *req;
|
|
Coroutine *self = qemu_coroutine_self();
|
|
|
|
QLIST_FOREACH(req, &bs->tracked_requests, list) {
|
|
if (req->co == self) {
|
|
return req;
|
|
}
|
|
}
|
|
|
|
return NULL;
|
|
}
|
|
|
|
/**
|
|
* Round a region to cluster boundaries
|
|
*/
|
|
void bdrv_round_to_clusters(BlockDriverState *bs,
|
|
int64_t offset, int64_t bytes,
|
|
int64_t *cluster_offset,
|
|
int64_t *cluster_bytes)
|
|
{
|
|
BlockDriverInfo bdi;
|
|
|
|
if (bdrv_get_info(bs, &bdi) < 0 || bdi.cluster_size == 0) {
|
|
*cluster_offset = offset;
|
|
*cluster_bytes = bytes;
|
|
} else {
|
|
int64_t c = bdi.cluster_size;
|
|
*cluster_offset = QEMU_ALIGN_DOWN(offset, c);
|
|
*cluster_bytes = QEMU_ALIGN_UP(offset - *cluster_offset + bytes, c);
|
|
}
|
|
}
|
|
|
|
static int bdrv_get_cluster_size(BlockDriverState *bs)
|
|
{
|
|
BlockDriverInfo bdi;
|
|
int ret;
|
|
|
|
ret = bdrv_get_info(bs, &bdi);
|
|
if (ret < 0 || bdi.cluster_size == 0) {
|
|
return bs->bl.request_alignment;
|
|
} else {
|
|
return bdi.cluster_size;
|
|
}
|
|
}
|
|
|
|
void bdrv_inc_in_flight(BlockDriverState *bs)
|
|
{
|
|
qatomic_inc(&bs->in_flight);
|
|
}
|
|
|
|
void bdrv_wakeup(BlockDriverState *bs)
|
|
{
|
|
aio_wait_kick();
|
|
}
|
|
|
|
void bdrv_dec_in_flight(BlockDriverState *bs)
|
|
{
|
|
qatomic_dec(&bs->in_flight);
|
|
bdrv_wakeup(bs);
|
|
}
|
|
|
|
static bool coroutine_fn bdrv_wait_serialising_requests(BdrvTrackedRequest *self)
|
|
{
|
|
BlockDriverState *bs = self->bs;
|
|
bool waited = false;
|
|
|
|
if (!qatomic_read(&bs->serialising_in_flight)) {
|
|
return false;
|
|
}
|
|
|
|
qemu_co_mutex_lock(&bs->reqs_lock);
|
|
waited = bdrv_wait_serialising_requests_locked(bs, self);
|
|
qemu_co_mutex_unlock(&bs->reqs_lock);
|
|
|
|
return waited;
|
|
}
|
|
|
|
static int bdrv_check_byte_request(BlockDriverState *bs, int64_t offset,
|
|
size_t size)
|
|
{
|
|
if (size > BDRV_REQUEST_MAX_BYTES) {
|
|
return -EIO;
|
|
}
|
|
|
|
if (!bdrv_is_inserted(bs)) {
|
|
return -ENOMEDIUM;
|
|
}
|
|
|
|
if (offset < 0) {
|
|
return -EIO;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
typedef int coroutine_fn BdrvRequestEntry(void *opaque);
|
|
typedef struct BdrvRunCo {
|
|
BdrvRequestEntry *entry;
|
|
void *opaque;
|
|
int ret;
|
|
bool done;
|
|
Coroutine *co; /* Coroutine, running bdrv_run_co_entry, for debugging */
|
|
} BdrvRunCo;
|
|
|
|
static void coroutine_fn bdrv_run_co_entry(void *opaque)
|
|
{
|
|
BdrvRunCo *arg = opaque;
|
|
|
|
arg->ret = arg->entry(arg->opaque);
|
|
arg->done = true;
|
|
aio_wait_kick();
|
|
}
|
|
|
|
static int bdrv_run_co(BlockDriverState *bs, BdrvRequestEntry *entry,
|
|
void *opaque)
|
|
{
|
|
if (qemu_in_coroutine()) {
|
|
/* Fast-path if already in coroutine context */
|
|
return entry(opaque);
|
|
} else {
|
|
BdrvRunCo s = { .entry = entry, .opaque = opaque };
|
|
|
|
s.co = qemu_coroutine_create(bdrv_run_co_entry, &s);
|
|
bdrv_coroutine_enter(bs, s.co);
|
|
|
|
BDRV_POLL_WHILE(bs, !s.done);
|
|
|
|
return s.ret;
|
|
}
|
|
}
|
|
|
|
typedef struct RwCo {
|
|
BdrvChild *child;
|
|
int64_t offset;
|
|
QEMUIOVector *qiov;
|
|
bool is_write;
|
|
BdrvRequestFlags flags;
|
|
} RwCo;
|
|
|
|
static int coroutine_fn bdrv_rw_co_entry(void *opaque)
|
|
{
|
|
RwCo *rwco = opaque;
|
|
|
|
if (!rwco->is_write) {
|
|
return bdrv_co_preadv(rwco->child, rwco->offset,
|
|
rwco->qiov->size, rwco->qiov,
|
|
rwco->flags);
|
|
} else {
|
|
return bdrv_co_pwritev(rwco->child, rwco->offset,
|
|
rwco->qiov->size, rwco->qiov,
|
|
rwco->flags);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Process a vectored synchronous request using coroutines
|
|
*/
|
|
static int bdrv_prwv_co(BdrvChild *child, int64_t offset,
|
|
QEMUIOVector *qiov, bool is_write,
|
|
BdrvRequestFlags flags)
|
|
{
|
|
RwCo rwco = {
|
|
.child = child,
|
|
.offset = offset,
|
|
.qiov = qiov,
|
|
.is_write = is_write,
|
|
.flags = flags,
|
|
};
|
|
|
|
return bdrv_run_co(child->bs, bdrv_rw_co_entry, &rwco);
|
|
}
|
|
|
|
int bdrv_pwrite_zeroes(BdrvChild *child, int64_t offset,
|
|
int bytes, BdrvRequestFlags flags)
|
|
{
|
|
QEMUIOVector qiov = QEMU_IOVEC_INIT_BUF(qiov, NULL, bytes);
|
|
|
|
return bdrv_prwv_co(child, offset, &qiov, true,
|
|
BDRV_REQ_ZERO_WRITE | flags);
|
|
}
|
|
|
|
/*
|
|
* Completely zero out a block device with the help of bdrv_pwrite_zeroes.
|
|
* The operation is sped up by checking the block status and only writing
|
|
* zeroes to the device if they currently do not return zeroes. Optional
|
|
* flags are passed through to bdrv_pwrite_zeroes (e.g. BDRV_REQ_MAY_UNMAP,
|
|
* BDRV_REQ_FUA).
|
|
*
|
|
* Returns < 0 on error, 0 on success. For error codes see bdrv_pwrite().
|
|
*/
|
|
int bdrv_make_zero(BdrvChild *child, BdrvRequestFlags flags)
|
|
{
|
|
int ret;
|
|
int64_t target_size, bytes, offset = 0;
|
|
BlockDriverState *bs = child->bs;
|
|
|
|
target_size = bdrv_getlength(bs);
|
|
if (target_size < 0) {
|
|
return target_size;
|
|
}
|
|
|
|
for (;;) {
|
|
bytes = MIN(target_size - offset, BDRV_REQUEST_MAX_BYTES);
|
|
if (bytes <= 0) {
|
|
return 0;
|
|
}
|
|
ret = bdrv_block_status(bs, offset, bytes, &bytes, NULL, NULL);
|
|
if (ret < 0) {
|
|
return ret;
|
|
}
|
|
if (ret & BDRV_BLOCK_ZERO) {
|
|
offset += bytes;
|
|
continue;
|
|
}
|
|
ret = bdrv_pwrite_zeroes(child, offset, bytes, flags);
|
|
if (ret < 0) {
|
|
return ret;
|
|
}
|
|
offset += bytes;
|
|
}
|
|
}
|
|
|
|
/* return < 0 if error. See bdrv_pwrite() for the return codes */
|
|
int bdrv_preadv(BdrvChild *child, int64_t offset, QEMUIOVector *qiov)
|
|
{
|
|
int ret;
|
|
|
|
ret = bdrv_prwv_co(child, offset, qiov, false, 0);
|
|
if (ret < 0) {
|
|
return ret;
|
|
}
|
|
|
|
return qiov->size;
|
|
}
|
|
|
|
/* See bdrv_pwrite() for the return codes */
|
|
int bdrv_pread(BdrvChild *child, int64_t offset, void *buf, int bytes)
|
|
{
|
|
QEMUIOVector qiov = QEMU_IOVEC_INIT_BUF(qiov, buf, bytes);
|
|
|
|
if (bytes < 0) {
|
|
return -EINVAL;
|
|
}
|
|
|
|
return bdrv_preadv(child, offset, &qiov);
|
|
}
|
|
|
|
int bdrv_pwritev(BdrvChild *child, int64_t offset, QEMUIOVector *qiov)
|
|
{
|
|
int ret;
|
|
|
|
ret = bdrv_prwv_co(child, offset, qiov, true, 0);
|
|
if (ret < 0) {
|
|
return ret;
|
|
}
|
|
|
|
return qiov->size;
|
|
}
|
|
|
|
/* Return no. of bytes on success or < 0 on error. Important errors are:
|
|
-EIO generic I/O error (may happen for all errors)
|
|
-ENOMEDIUM No media inserted.
|
|
-EINVAL Invalid offset or number of bytes
|
|
-EACCES Trying to write a read-only device
|
|
*/
|
|
int bdrv_pwrite(BdrvChild *child, int64_t offset, const void *buf, int bytes)
|
|
{
|
|
QEMUIOVector qiov = QEMU_IOVEC_INIT_BUF(qiov, buf, bytes);
|
|
|
|
if (bytes < 0) {
|
|
return -EINVAL;
|
|
}
|
|
|
|
return bdrv_pwritev(child, offset, &qiov);
|
|
}
|
|
|
|
/*
|
|
* Writes to the file and ensures that no writes are reordered across this
|
|
* request (acts as a barrier)
|
|
*
|
|
* Returns 0 on success, -errno in error cases.
|
|
*/
|
|
int bdrv_pwrite_sync(BdrvChild *child, int64_t offset,
|
|
const void *buf, int count)
|
|
{
|
|
int ret;
|
|
|
|
ret = bdrv_pwrite(child, offset, buf, count);
|
|
if (ret < 0) {
|
|
return ret;
|
|
}
|
|
|
|
ret = bdrv_flush(child->bs);
|
|
if (ret < 0) {
|
|
return ret;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
typedef struct CoroutineIOCompletion {
|
|
Coroutine *coroutine;
|
|
int ret;
|
|
} CoroutineIOCompletion;
|
|
|
|
static void bdrv_co_io_em_complete(void *opaque, int ret)
|
|
{
|
|
CoroutineIOCompletion *co = opaque;
|
|
|
|
co->ret = ret;
|
|
aio_co_wake(co->coroutine);
|
|
}
|
|
|
|
static int coroutine_fn bdrv_driver_preadv(BlockDriverState *bs,
|
|
uint64_t offset, uint64_t bytes,
|
|
QEMUIOVector *qiov,
|
|
size_t qiov_offset, int flags)
|
|
{
|
|
BlockDriver *drv = bs->drv;
|
|
int64_t sector_num;
|
|
unsigned int nb_sectors;
|
|
QEMUIOVector local_qiov;
|
|
int ret;
|
|
|
|
assert(!(flags & ~BDRV_REQ_MASK));
|
|
assert(!(flags & BDRV_REQ_NO_FALLBACK));
|
|
|
|
if (!drv) {
|
|
return -ENOMEDIUM;
|
|
}
|
|
|
|
if (drv->bdrv_co_preadv_part) {
|
|
return drv->bdrv_co_preadv_part(bs, offset, bytes, qiov, qiov_offset,
|
|
flags);
|
|
}
|
|
|
|
if (qiov_offset > 0 || bytes != qiov->size) {
|
|
qemu_iovec_init_slice(&local_qiov, qiov, qiov_offset, bytes);
|
|
qiov = &local_qiov;
|
|
}
|
|
|
|
if (drv->bdrv_co_preadv) {
|
|
ret = drv->bdrv_co_preadv(bs, offset, bytes, qiov, flags);
|
|
goto out;
|
|
}
|
|
|
|
if (drv->bdrv_aio_preadv) {
|
|
BlockAIOCB *acb;
|
|
CoroutineIOCompletion co = {
|
|
.coroutine = qemu_coroutine_self(),
|
|
};
|
|
|
|
acb = drv->bdrv_aio_preadv(bs, offset, bytes, qiov, flags,
|
|
bdrv_co_io_em_complete, &co);
|
|
if (acb == NULL) {
|
|
ret = -EIO;
|
|
goto out;
|
|
} else {
|
|
qemu_coroutine_yield();
|
|
ret = co.ret;
|
|
goto out;
|
|
}
|
|
}
|
|
|
|
sector_num = offset >> BDRV_SECTOR_BITS;
|
|
nb_sectors = bytes >> BDRV_SECTOR_BITS;
|
|
|
|
assert(QEMU_IS_ALIGNED(offset, BDRV_SECTOR_SIZE));
|
|
assert(QEMU_IS_ALIGNED(bytes, BDRV_SECTOR_SIZE));
|
|
assert(bytes <= BDRV_REQUEST_MAX_BYTES);
|
|
assert(drv->bdrv_co_readv);
|
|
|
|
ret = drv->bdrv_co_readv(bs, sector_num, nb_sectors, qiov);
|
|
|
|
out:
|
|
if (qiov == &local_qiov) {
|
|
qemu_iovec_destroy(&local_qiov);
|
|
}
|
|
|
|
return ret;
|
|
}
|
|
|
|
static int coroutine_fn bdrv_driver_pwritev(BlockDriverState *bs,
|
|
uint64_t offset, uint64_t bytes,
|
|
QEMUIOVector *qiov,
|
|
size_t qiov_offset, int flags)
|
|
{
|
|
BlockDriver *drv = bs->drv;
|
|
int64_t sector_num;
|
|
unsigned int nb_sectors;
|
|
QEMUIOVector local_qiov;
|
|
int ret;
|
|
|
|
assert(!(flags & ~BDRV_REQ_MASK));
|
|
assert(!(flags & BDRV_REQ_NO_FALLBACK));
|
|
|
|
if (!drv) {
|
|
return -ENOMEDIUM;
|
|
}
|
|
|
|
if (drv->bdrv_co_pwritev_part) {
|
|
ret = drv->bdrv_co_pwritev_part(bs, offset, bytes, qiov, qiov_offset,
|
|
flags & bs->supported_write_flags);
|
|
flags &= ~bs->supported_write_flags;
|
|
goto emulate_flags;
|
|
}
|
|
|
|
if (qiov_offset > 0 || bytes != qiov->size) {
|
|
qemu_iovec_init_slice(&local_qiov, qiov, qiov_offset, bytes);
|
|
qiov = &local_qiov;
|
|
}
|
|
|
|
if (drv->bdrv_co_pwritev) {
|
|
ret = drv->bdrv_co_pwritev(bs, offset, bytes, qiov,
|
|
flags & bs->supported_write_flags);
|
|
flags &= ~bs->supported_write_flags;
|
|
goto emulate_flags;
|
|
}
|
|
|
|
if (drv->bdrv_aio_pwritev) {
|
|
BlockAIOCB *acb;
|
|
CoroutineIOCompletion co = {
|
|
.coroutine = qemu_coroutine_self(),
|
|
};
|
|
|
|
acb = drv->bdrv_aio_pwritev(bs, offset, bytes, qiov,
|
|
flags & bs->supported_write_flags,
|
|
bdrv_co_io_em_complete, &co);
|
|
flags &= ~bs->supported_write_flags;
|
|
if (acb == NULL) {
|
|
ret = -EIO;
|
|
} else {
|
|
qemu_coroutine_yield();
|
|
ret = co.ret;
|
|
}
|
|
goto emulate_flags;
|
|
}
|
|
|
|
sector_num = offset >> BDRV_SECTOR_BITS;
|
|
nb_sectors = bytes >> BDRV_SECTOR_BITS;
|
|
|
|
assert(QEMU_IS_ALIGNED(offset, BDRV_SECTOR_SIZE));
|
|
assert(QEMU_IS_ALIGNED(bytes, BDRV_SECTOR_SIZE));
|
|
assert(bytes <= BDRV_REQUEST_MAX_BYTES);
|
|
|
|
assert(drv->bdrv_co_writev);
|
|
ret = drv->bdrv_co_writev(bs, sector_num, nb_sectors, qiov,
|
|
flags & bs->supported_write_flags);
|
|
flags &= ~bs->supported_write_flags;
|
|
|
|
emulate_flags:
|
|
if (ret == 0 && (flags & BDRV_REQ_FUA)) {
|
|
ret = bdrv_co_flush(bs);
|
|
}
|
|
|
|
if (qiov == &local_qiov) {
|
|
qemu_iovec_destroy(&local_qiov);
|
|
}
|
|
|
|
return ret;
|
|
}
|
|
|
|
static int coroutine_fn
|
|
bdrv_driver_pwritev_compressed(BlockDriverState *bs, uint64_t offset,
|
|
uint64_t bytes, QEMUIOVector *qiov,
|
|
size_t qiov_offset)
|
|
{
|
|
BlockDriver *drv = bs->drv;
|
|
QEMUIOVector local_qiov;
|
|
int ret;
|
|
|
|
if (!drv) {
|
|
return -ENOMEDIUM;
|
|
}
|
|
|
|
if (!block_driver_can_compress(drv)) {
|
|
return -ENOTSUP;
|
|
}
|
|
|
|
if (drv->bdrv_co_pwritev_compressed_part) {
|
|
return drv->bdrv_co_pwritev_compressed_part(bs, offset, bytes,
|
|
qiov, qiov_offset);
|
|
}
|
|
|
|
if (qiov_offset == 0) {
|
|
return drv->bdrv_co_pwritev_compressed(bs, offset, bytes, qiov);
|
|
}
|
|
|
|
qemu_iovec_init_slice(&local_qiov, qiov, qiov_offset, bytes);
|
|
ret = drv->bdrv_co_pwritev_compressed(bs, offset, bytes, &local_qiov);
|
|
qemu_iovec_destroy(&local_qiov);
|
|
|
|
return ret;
|
|
}
|
|
|
|
static int coroutine_fn bdrv_co_do_copy_on_readv(BdrvChild *child,
|
|
int64_t offset, unsigned int bytes, QEMUIOVector *qiov,
|
|
size_t qiov_offset, int flags)
|
|
{
|
|
BlockDriverState *bs = child->bs;
|
|
|
|
/* Perform I/O through a temporary buffer so that users who scribble over
|
|
* their read buffer while the operation is in progress do not end up
|
|
* modifying the image file. This is critical for zero-copy guest I/O
|
|
* where anything might happen inside guest memory.
|
|
*/
|
|
void *bounce_buffer = NULL;
|
|
|
|
BlockDriver *drv = bs->drv;
|
|
int64_t cluster_offset;
|
|
int64_t cluster_bytes;
|
|
size_t skip_bytes;
|
|
int ret;
|
|
int max_transfer = MIN_NON_ZERO(bs->bl.max_transfer,
|
|
BDRV_REQUEST_MAX_BYTES);
|
|
unsigned int progress = 0;
|
|
bool skip_write;
|
|
|
|
if (!drv) {
|
|
return -ENOMEDIUM;
|
|
}
|
|
|
|
/*
|
|
* Do not write anything when the BDS is inactive. That is not
|
|
* allowed, and it would not help.
|
|
*/
|
|
skip_write = (bs->open_flags & BDRV_O_INACTIVE);
|
|
|
|
/* FIXME We cannot require callers to have write permissions when all they
|
|
* are doing is a read request. If we did things right, write permissions
|
|
* would be obtained anyway, but internally by the copy-on-read code. As
|
|
* long as it is implemented here rather than in a separate filter driver,
|
|
* the copy-on-read code doesn't have its own BdrvChild, however, for which
|
|
* it could request permissions. Therefore we have to bypass the permission
|
|
* system for the moment. */
|
|
// assert(child->perm & (BLK_PERM_WRITE_UNCHANGED | BLK_PERM_WRITE));
|
|
|
|
/* Cover entire cluster so no additional backing file I/O is required when
|
|
* allocating cluster in the image file. Note that this value may exceed
|
|
* BDRV_REQUEST_MAX_BYTES (even when the original read did not), which
|
|
* is one reason we loop rather than doing it all at once.
|
|
*/
|
|
bdrv_round_to_clusters(bs, offset, bytes, &cluster_offset, &cluster_bytes);
|
|
skip_bytes = offset - cluster_offset;
|
|
|
|
trace_bdrv_co_do_copy_on_readv(bs, offset, bytes,
|
|
cluster_offset, cluster_bytes);
|
|
|
|
while (cluster_bytes) {
|
|
int64_t pnum;
|
|
|
|
if (skip_write) {
|
|
ret = 1; /* "already allocated", so nothing will be copied */
|
|
pnum = MIN(cluster_bytes, max_transfer);
|
|
} else {
|
|
ret = bdrv_is_allocated(bs, cluster_offset,
|
|
MIN(cluster_bytes, max_transfer), &pnum);
|
|
if (ret < 0) {
|
|
/*
|
|
* Safe to treat errors in querying allocation as if
|
|
* unallocated; we'll probably fail again soon on the
|
|
* read, but at least that will set a decent errno.
|
|
*/
|
|
pnum = MIN(cluster_bytes, max_transfer);
|
|
}
|
|
|
|
/* Stop at EOF if the image ends in the middle of the cluster */
|
|
if (ret == 0 && pnum == 0) {
|
|
assert(progress >= bytes);
|
|
break;
|
|
}
|
|
|
|
assert(skip_bytes < pnum);
|
|
}
|
|
|
|
if (ret <= 0) {
|
|
QEMUIOVector local_qiov;
|
|
|
|
/* Must copy-on-read; use the bounce buffer */
|
|
pnum = MIN(pnum, MAX_BOUNCE_BUFFER);
|
|
if (!bounce_buffer) {
|
|
int64_t max_we_need = MAX(pnum, cluster_bytes - pnum);
|
|
int64_t max_allowed = MIN(max_transfer, MAX_BOUNCE_BUFFER);
|
|
int64_t bounce_buffer_len = MIN(max_we_need, max_allowed);
|
|
|
|
bounce_buffer = qemu_try_blockalign(bs, bounce_buffer_len);
|
|
if (!bounce_buffer) {
|
|
ret = -ENOMEM;
|
|
goto err;
|
|
}
|
|
}
|
|
qemu_iovec_init_buf(&local_qiov, bounce_buffer, pnum);
|
|
|
|
ret = bdrv_driver_preadv(bs, cluster_offset, pnum,
|
|
&local_qiov, 0, 0);
|
|
if (ret < 0) {
|
|
goto err;
|
|
}
|
|
|
|
bdrv_debug_event(bs, BLKDBG_COR_WRITE);
|
|
if (drv->bdrv_co_pwrite_zeroes &&
|
|
buffer_is_zero(bounce_buffer, pnum)) {
|
|
/* FIXME: Should we (perhaps conditionally) be setting
|
|
* BDRV_REQ_MAY_UNMAP, if it will allow for a sparser copy
|
|
* that still correctly reads as zero? */
|
|
ret = bdrv_co_do_pwrite_zeroes(bs, cluster_offset, pnum,
|
|
BDRV_REQ_WRITE_UNCHANGED);
|
|
} else {
|
|
/* This does not change the data on the disk, it is not
|
|
* necessary to flush even in cache=writethrough mode.
|
|
*/
|
|
ret = bdrv_driver_pwritev(bs, cluster_offset, pnum,
|
|
&local_qiov, 0,
|
|
BDRV_REQ_WRITE_UNCHANGED);
|
|
}
|
|
|
|
if (ret < 0) {
|
|
/* It might be okay to ignore write errors for guest
|
|
* requests. If this is a deliberate copy-on-read
|
|
* then we don't want to ignore the error. Simply
|
|
* report it in all cases.
|
|
*/
|
|
goto err;
|
|
}
|
|
|
|
if (!(flags & BDRV_REQ_PREFETCH)) {
|
|
qemu_iovec_from_buf(qiov, qiov_offset + progress,
|
|
bounce_buffer + skip_bytes,
|
|
MIN(pnum - skip_bytes, bytes - progress));
|
|
}
|
|
} else if (!(flags & BDRV_REQ_PREFETCH)) {
|
|
/* Read directly into the destination */
|
|
ret = bdrv_driver_preadv(bs, offset + progress,
|
|
MIN(pnum - skip_bytes, bytes - progress),
|
|
qiov, qiov_offset + progress, 0);
|
|
if (ret < 0) {
|
|
goto err;
|
|
}
|
|
}
|
|
|
|
cluster_offset += pnum;
|
|
cluster_bytes -= pnum;
|
|
progress += pnum - skip_bytes;
|
|
skip_bytes = 0;
|
|
}
|
|
ret = 0;
|
|
|
|
err:
|
|
qemu_vfree(bounce_buffer);
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* Forwards an already correctly aligned request to the BlockDriver. This
|
|
* handles copy on read, zeroing after EOF, and fragmentation of large
|
|
* reads; any other features must be implemented by the caller.
|
|
*/
|
|
static int coroutine_fn bdrv_aligned_preadv(BdrvChild *child,
|
|
BdrvTrackedRequest *req, int64_t offset, unsigned int bytes,
|
|
int64_t align, QEMUIOVector *qiov, size_t qiov_offset, int flags)
|
|
{
|
|
BlockDriverState *bs = child->bs;
|
|
int64_t total_bytes, max_bytes;
|
|
int ret = 0;
|
|
uint64_t bytes_remaining = bytes;
|
|
int max_transfer;
|
|
|
|
assert(is_power_of_2(align));
|
|
assert((offset & (align - 1)) == 0);
|
|
assert((bytes & (align - 1)) == 0);
|
|
assert((bs->open_flags & BDRV_O_NO_IO) == 0);
|
|
max_transfer = QEMU_ALIGN_DOWN(MIN_NON_ZERO(bs->bl.max_transfer, INT_MAX),
|
|
align);
|
|
|
|
/* TODO: We would need a per-BDS .supported_read_flags and
|
|
* potential fallback support, if we ever implement any read flags
|
|
* to pass through to drivers. For now, there aren't any
|
|
* passthrough flags. */
|
|
assert(!(flags & ~(BDRV_REQ_COPY_ON_READ | BDRV_REQ_PREFETCH)));
|
|
|
|
/* Handle Copy on Read and associated serialisation */
|
|
if (flags & BDRV_REQ_COPY_ON_READ) {
|
|
/* If we touch the same cluster it counts as an overlap. This
|
|
* guarantees that allocating writes will be serialized and not race
|
|
* with each other for the same cluster. For example, in copy-on-read
|
|
* it ensures that the CoR read and write operations are atomic and
|
|
* guest writes cannot interleave between them. */
|
|
bdrv_mark_request_serialising(req, bdrv_get_cluster_size(bs));
|
|
} else {
|
|
bdrv_wait_serialising_requests(req);
|
|
}
|
|
|
|
if (flags & BDRV_REQ_COPY_ON_READ) {
|
|
int64_t pnum;
|
|
|
|
ret = bdrv_is_allocated(bs, offset, bytes, &pnum);
|
|
if (ret < 0) {
|
|
goto out;
|
|
}
|
|
|
|
if (!ret || pnum != bytes) {
|
|
ret = bdrv_co_do_copy_on_readv(child, offset, bytes,
|
|
qiov, qiov_offset, flags);
|
|
goto out;
|
|
} else if (flags & BDRV_REQ_PREFETCH) {
|
|
goto out;
|
|
}
|
|
}
|
|
|
|
/* Forward the request to the BlockDriver, possibly fragmenting it */
|
|
total_bytes = bdrv_getlength(bs);
|
|
if (total_bytes < 0) {
|
|
ret = total_bytes;
|
|
goto out;
|
|
}
|
|
|
|
max_bytes = ROUND_UP(MAX(0, total_bytes - offset), align);
|
|
if (bytes <= max_bytes && bytes <= max_transfer) {
|
|
ret = bdrv_driver_preadv(bs, offset, bytes, qiov, qiov_offset, 0);
|
|
goto out;
|
|
}
|
|
|
|
while (bytes_remaining) {
|
|
int num;
|
|
|
|
if (max_bytes) {
|
|
num = MIN(bytes_remaining, MIN(max_bytes, max_transfer));
|
|
assert(num);
|
|
|
|
ret = bdrv_driver_preadv(bs, offset + bytes - bytes_remaining,
|
|
num, qiov,
|
|
qiov_offset + bytes - bytes_remaining, 0);
|
|
max_bytes -= num;
|
|
} else {
|
|
num = bytes_remaining;
|
|
ret = qemu_iovec_memset(qiov, qiov_offset + bytes - bytes_remaining,
|
|
0, bytes_remaining);
|
|
}
|
|
if (ret < 0) {
|
|
goto out;
|
|
}
|
|
bytes_remaining -= num;
|
|
}
|
|
|
|
out:
|
|
return ret < 0 ? ret : 0;
|
|
}
|
|
|
|
/*
|
|
* Request padding
|
|
*
|
|
* |<---- align ----->| |<----- align ---->|
|
|
* |<- head ->|<------------- bytes ------------->|<-- tail -->|
|
|
* | | | | | |
|
|
* -*----------$-------*-------- ... --------*-----$------------*---
|
|
* | | | | | |
|
|
* | offset | | end |
|
|
* ALIGN_DOWN(offset) ALIGN_UP(offset) ALIGN_DOWN(end) ALIGN_UP(end)
|
|
* [buf ... ) [tail_buf )
|
|
*
|
|
* @buf is an aligned allocation needed to store @head and @tail paddings. @head
|
|
* is placed at the beginning of @buf and @tail at the @end.
|
|
*
|
|
* @tail_buf is a pointer to sub-buffer, corresponding to align-sized chunk
|
|
* around tail, if tail exists.
|
|
*
|
|
* @merge_reads is true for small requests,
|
|
* if @buf_len == @head + bytes + @tail. In this case it is possible that both
|
|
* head and tail exist but @buf_len == align and @tail_buf == @buf.
|
|
*/
|
|
typedef struct BdrvRequestPadding {
|
|
uint8_t *buf;
|
|
size_t buf_len;
|
|
uint8_t *tail_buf;
|
|
size_t head;
|
|
size_t tail;
|
|
bool merge_reads;
|
|
QEMUIOVector local_qiov;
|
|
} BdrvRequestPadding;
|
|
|
|
static bool bdrv_init_padding(BlockDriverState *bs,
|
|
int64_t offset, int64_t bytes,
|
|
BdrvRequestPadding *pad)
|
|
{
|
|
uint64_t align = bs->bl.request_alignment;
|
|
size_t sum;
|
|
|
|
memset(pad, 0, sizeof(*pad));
|
|
|
|
pad->head = offset & (align - 1);
|
|
pad->tail = ((offset + bytes) & (align - 1));
|
|
if (pad->tail) {
|
|
pad->tail = align - pad->tail;
|
|
}
|
|
|
|
if (!pad->head && !pad->tail) {
|
|
return false;
|
|
}
|
|
|
|
assert(bytes); /* Nothing good in aligning zero-length requests */
|
|
|
|
sum = pad->head + bytes + pad->tail;
|
|
pad->buf_len = (sum > align && pad->head && pad->tail) ? 2 * align : align;
|
|
pad->buf = qemu_blockalign(bs, pad->buf_len);
|
|
pad->merge_reads = sum == pad->buf_len;
|
|
if (pad->tail) {
|
|
pad->tail_buf = pad->buf + pad->buf_len - align;
|
|
}
|
|
|
|
return true;
|
|
}
|
|
|
|
static int bdrv_padding_rmw_read(BdrvChild *child,
|
|
BdrvTrackedRequest *req,
|
|
BdrvRequestPadding *pad,
|
|
bool zero_middle)
|
|
{
|
|
QEMUIOVector local_qiov;
|
|
BlockDriverState *bs = child->bs;
|
|
uint64_t align = bs->bl.request_alignment;
|
|
int ret;
|
|
|
|
assert(req->serialising && pad->buf);
|
|
|
|
if (pad->head || pad->merge_reads) {
|
|
uint64_t bytes = pad->merge_reads ? pad->buf_len : align;
|
|
|
|
qemu_iovec_init_buf(&local_qiov, pad->buf, bytes);
|
|
|
|
if (pad->head) {
|
|
bdrv_debug_event(bs, BLKDBG_PWRITEV_RMW_HEAD);
|
|
}
|
|
if (pad->merge_reads && pad->tail) {
|
|
bdrv_debug_event(bs, BLKDBG_PWRITEV_RMW_TAIL);
|
|
}
|
|
ret = bdrv_aligned_preadv(child, req, req->overlap_offset, bytes,
|
|
align, &local_qiov, 0, 0);
|
|
if (ret < 0) {
|
|
return ret;
|
|
}
|
|
if (pad->head) {
|
|
bdrv_debug_event(bs, BLKDBG_PWRITEV_RMW_AFTER_HEAD);
|
|
}
|
|
if (pad->merge_reads && pad->tail) {
|
|
bdrv_debug_event(bs, BLKDBG_PWRITEV_RMW_AFTER_TAIL);
|
|
}
|
|
|
|
if (pad->merge_reads) {
|
|
goto zero_mem;
|
|
}
|
|
}
|
|
|
|
if (pad->tail) {
|
|
qemu_iovec_init_buf(&local_qiov, pad->tail_buf, align);
|
|
|
|
bdrv_debug_event(bs, BLKDBG_PWRITEV_RMW_TAIL);
|
|
ret = bdrv_aligned_preadv(
|
|
child, req,
|
|
req->overlap_offset + req->overlap_bytes - align,
|
|
align, align, &local_qiov, 0, 0);
|
|
if (ret < 0) {
|
|
return ret;
|
|
}
|
|
bdrv_debug_event(bs, BLKDBG_PWRITEV_RMW_AFTER_TAIL);
|
|
}
|
|
|
|
zero_mem:
|
|
if (zero_middle) {
|
|
memset(pad->buf + pad->head, 0, pad->buf_len - pad->head - pad->tail);
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
static void bdrv_padding_destroy(BdrvRequestPadding *pad)
|
|
{
|
|
if (pad->buf) {
|
|
qemu_vfree(pad->buf);
|
|
qemu_iovec_destroy(&pad->local_qiov);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* bdrv_pad_request
|
|
*
|
|
* Exchange request parameters with padded request if needed. Don't include RMW
|
|
* read of padding, bdrv_padding_rmw_read() should be called separately if
|
|
* needed.
|
|
*
|
|
* All parameters except @bs are in-out: they represent original request at
|
|
* function call and padded (if padding needed) at function finish.
|
|
*
|
|
* Function always succeeds.
|
|
*/
|
|
static bool bdrv_pad_request(BlockDriverState *bs,
|
|
QEMUIOVector **qiov, size_t *qiov_offset,
|
|
int64_t *offset, unsigned int *bytes,
|
|
BdrvRequestPadding *pad)
|
|
{
|
|
if (!bdrv_init_padding(bs, *offset, *bytes, pad)) {
|
|
return false;
|
|
}
|
|
|
|
qemu_iovec_init_extended(&pad->local_qiov, pad->buf, pad->head,
|
|
*qiov, *qiov_offset, *bytes,
|
|
pad->buf + pad->buf_len - pad->tail, pad->tail);
|
|
*bytes += pad->head + pad->tail;
|
|
*offset -= pad->head;
|
|
*qiov = &pad->local_qiov;
|
|
*qiov_offset = 0;
|
|
|
|
return true;
|
|
}
|
|
|
|
int coroutine_fn bdrv_co_preadv(BdrvChild *child,
|
|
int64_t offset, unsigned int bytes, QEMUIOVector *qiov,
|
|
BdrvRequestFlags flags)
|
|
{
|
|
return bdrv_co_preadv_part(child, offset, bytes, qiov, 0, flags);
|
|
}
|
|
|
|
int coroutine_fn bdrv_co_preadv_part(BdrvChild *child,
|
|
int64_t offset, unsigned int bytes,
|
|
QEMUIOVector *qiov, size_t qiov_offset,
|
|
BdrvRequestFlags flags)
|
|
{
|
|
BlockDriverState *bs = child->bs;
|
|
BdrvTrackedRequest req;
|
|
BdrvRequestPadding pad;
|
|
int ret;
|
|
|
|
trace_bdrv_co_preadv(bs, offset, bytes, flags);
|
|
|
|
ret = bdrv_check_byte_request(bs, offset, bytes);
|
|
if (ret < 0) {
|
|
return ret;
|
|
}
|
|
|
|
if (bytes == 0 && !QEMU_IS_ALIGNED(offset, bs->bl.request_alignment)) {
|
|
/*
|
|
* Aligning zero request is nonsense. Even if driver has special meaning
|
|
* of zero-length (like qcow2_co_pwritev_compressed_part), we can't pass
|
|
* it to driver due to request_alignment.
|
|
*
|
|
* Still, no reason to return an error if someone do unaligned
|
|
* zero-length read occasionally.
|
|
*/
|
|
return 0;
|
|
}
|
|
|
|
bdrv_inc_in_flight(bs);
|
|
|
|
/* Don't do copy-on-read if we read data before write operation */
|
|
if (qatomic_read(&bs->copy_on_read)) {
|
|
flags |= BDRV_REQ_COPY_ON_READ;
|
|
}
|
|
|
|
bdrv_pad_request(bs, &qiov, &qiov_offset, &offset, &bytes, &pad);
|
|
|
|
tracked_request_begin(&req, bs, offset, bytes, BDRV_TRACKED_READ);
|
|
ret = bdrv_aligned_preadv(child, &req, offset, bytes,
|
|
bs->bl.request_alignment,
|
|
qiov, qiov_offset, flags);
|
|
tracked_request_end(&req);
|
|
bdrv_dec_in_flight(bs);
|
|
|
|
bdrv_padding_destroy(&pad);
|
|
|
|
return ret;
|
|
}
|
|
|
|
static int coroutine_fn bdrv_co_do_pwrite_zeroes(BlockDriverState *bs,
|
|
int64_t offset, int bytes, BdrvRequestFlags flags)
|
|
{
|
|
BlockDriver *drv = bs->drv;
|
|
QEMUIOVector qiov;
|
|
void *buf = NULL;
|
|
int ret = 0;
|
|
bool need_flush = false;
|
|
int head = 0;
|
|
int tail = 0;
|
|
|
|
int max_write_zeroes = MIN_NON_ZERO(bs->bl.max_pwrite_zeroes, INT_MAX);
|
|
int alignment = MAX(bs->bl.pwrite_zeroes_alignment,
|
|
bs->bl.request_alignment);
|
|
int max_transfer = MIN_NON_ZERO(bs->bl.max_transfer, MAX_BOUNCE_BUFFER);
|
|
|
|
if (!drv) {
|
|
return -ENOMEDIUM;
|
|
}
|
|
|
|
if ((flags & ~bs->supported_zero_flags) & BDRV_REQ_NO_FALLBACK) {
|
|
return -ENOTSUP;
|
|
}
|
|
|
|
assert(alignment % bs->bl.request_alignment == 0);
|
|
head = offset % alignment;
|
|
tail = (offset + bytes) % alignment;
|
|
max_write_zeroes = QEMU_ALIGN_DOWN(max_write_zeroes, alignment);
|
|
assert(max_write_zeroes >= bs->bl.request_alignment);
|
|
|
|
while (bytes > 0 && !ret) {
|
|
int num = bytes;
|
|
|
|
/* Align request. Block drivers can expect the "bulk" of the request
|
|
* to be aligned, and that unaligned requests do not cross cluster
|
|
* boundaries.
|
|
*/
|
|
if (head) {
|
|
/* Make a small request up to the first aligned sector. For
|
|
* convenience, limit this request to max_transfer even if
|
|
* we don't need to fall back to writes. */
|
|
num = MIN(MIN(bytes, max_transfer), alignment - head);
|
|
head = (head + num) % alignment;
|
|
assert(num < max_write_zeroes);
|
|
} else if (tail && num > alignment) {
|
|
/* Shorten the request to the last aligned sector. */
|
|
num -= tail;
|
|
}
|
|
|
|
/* limit request size */
|
|
if (num > max_write_zeroes) {
|
|
num = max_write_zeroes;
|
|
}
|
|
|
|
ret = -ENOTSUP;
|
|
/* First try the efficient write zeroes operation */
|
|
if (drv->bdrv_co_pwrite_zeroes) {
|
|
ret = drv->bdrv_co_pwrite_zeroes(bs, offset, num,
|
|
flags & bs->supported_zero_flags);
|
|
if (ret != -ENOTSUP && (flags & BDRV_REQ_FUA) &&
|
|
!(bs->supported_zero_flags & BDRV_REQ_FUA)) {
|
|
need_flush = true;
|
|
}
|
|
} else {
|
|
assert(!bs->supported_zero_flags);
|
|
}
|
|
|
|
if (ret == -ENOTSUP && !(flags & BDRV_REQ_NO_FALLBACK)) {
|
|
/* Fall back to bounce buffer if write zeroes is unsupported */
|
|
BdrvRequestFlags write_flags = flags & ~BDRV_REQ_ZERO_WRITE;
|
|
|
|
if ((flags & BDRV_REQ_FUA) &&
|
|
!(bs->supported_write_flags & BDRV_REQ_FUA)) {
|
|
/* No need for bdrv_driver_pwrite() to do a fallback
|
|
* flush on each chunk; use just one at the end */
|
|
write_flags &= ~BDRV_REQ_FUA;
|
|
need_flush = true;
|
|
}
|
|
num = MIN(num, max_transfer);
|
|
if (buf == NULL) {
|
|
buf = qemu_try_blockalign0(bs, num);
|
|
if (buf == NULL) {
|
|
ret = -ENOMEM;
|
|
goto fail;
|
|
}
|
|
}
|
|
qemu_iovec_init_buf(&qiov, buf, num);
|
|
|
|
ret = bdrv_driver_pwritev(bs, offset, num, &qiov, 0, write_flags);
|
|
|
|
/* Keep bounce buffer around if it is big enough for all
|
|
* all future requests.
|
|
*/
|
|
if (num < max_transfer) {
|
|
qemu_vfree(buf);
|
|
buf = NULL;
|
|
}
|
|
}
|
|
|
|
offset += num;
|
|
bytes -= num;
|
|
}
|
|
|
|
fail:
|
|
if (ret == 0 && need_flush) {
|
|
ret = bdrv_co_flush(bs);
|
|
}
|
|
qemu_vfree(buf);
|
|
return ret;
|
|
}
|
|
|
|
static inline int coroutine_fn
|
|
bdrv_co_write_req_prepare(BdrvChild *child, int64_t offset, uint64_t bytes,
|
|
BdrvTrackedRequest *req, int flags)
|
|
{
|
|
BlockDriverState *bs = child->bs;
|
|
bool waited;
|
|
int64_t end_sector = DIV_ROUND_UP(offset + bytes, BDRV_SECTOR_SIZE);
|
|
|
|
if (bs->read_only) {
|
|
return -EPERM;
|
|
}
|
|
|
|
assert(!(bs->open_flags & BDRV_O_INACTIVE));
|
|
assert((bs->open_flags & BDRV_O_NO_IO) == 0);
|
|
assert(!(flags & ~BDRV_REQ_MASK));
|
|
|
|
if (flags & BDRV_REQ_SERIALISING) {
|
|
waited = bdrv_mark_request_serialising(req, bdrv_get_cluster_size(bs));
|
|
/*
|
|
* For a misaligned request we should have already waited earlier,
|
|
* because we come after bdrv_padding_rmw_read which must be called
|
|
* with the request already marked as serialising.
|
|
*/
|
|
assert(!waited ||
|
|
(req->offset == req->overlap_offset &&
|
|
req->bytes == req->overlap_bytes));
|
|
} else {
|
|
bdrv_wait_serialising_requests(req);
|
|
}
|
|
|
|
assert(req->overlap_offset <= offset);
|
|
assert(offset + bytes <= req->overlap_offset + req->overlap_bytes);
|
|
assert(end_sector <= bs->total_sectors || child->perm & BLK_PERM_RESIZE);
|
|
|
|
switch (req->type) {
|
|
case BDRV_TRACKED_WRITE:
|
|
case BDRV_TRACKED_DISCARD:
|
|
if (flags & BDRV_REQ_WRITE_UNCHANGED) {
|
|
assert(child->perm & (BLK_PERM_WRITE_UNCHANGED | BLK_PERM_WRITE));
|
|
} else {
|
|
assert(child->perm & BLK_PERM_WRITE);
|
|
}
|
|
return notifier_with_return_list_notify(&bs->before_write_notifiers,
|
|
req);
|
|
case BDRV_TRACKED_TRUNCATE:
|
|
assert(child->perm & BLK_PERM_RESIZE);
|
|
return 0;
|
|
default:
|
|
abort();
|
|
}
|
|
}
|
|
|
|
static inline void coroutine_fn
|
|
bdrv_co_write_req_finish(BdrvChild *child, int64_t offset, uint64_t bytes,
|
|
BdrvTrackedRequest *req, int ret)
|
|
{
|
|
int64_t end_sector = DIV_ROUND_UP(offset + bytes, BDRV_SECTOR_SIZE);
|
|
BlockDriverState *bs = child->bs;
|
|
|
|
qatomic_inc(&bs->write_gen);
|
|
|
|
/*
|
|
* Discard cannot extend the image, but in error handling cases, such as
|
|
* when reverting a qcow2 cluster allocation, the discarded range can pass
|
|
* the end of image file, so we cannot assert about BDRV_TRACKED_DISCARD
|
|
* here. Instead, just skip it, since semantically a discard request
|
|
* beyond EOF cannot expand the image anyway.
|
|
*/
|
|
if (ret == 0 &&
|
|
(req->type == BDRV_TRACKED_TRUNCATE ||
|
|
end_sector > bs->total_sectors) &&
|
|
req->type != BDRV_TRACKED_DISCARD) {
|
|
bs->total_sectors = end_sector;
|
|
bdrv_parent_cb_resize(bs);
|
|
bdrv_dirty_bitmap_truncate(bs, end_sector << BDRV_SECTOR_BITS);
|
|
}
|
|
if (req->bytes) {
|
|
switch (req->type) {
|
|
case BDRV_TRACKED_WRITE:
|
|
stat64_max(&bs->wr_highest_offset, offset + bytes);
|
|
/* fall through, to set dirty bits */
|
|
case BDRV_TRACKED_DISCARD:
|
|
bdrv_set_dirty(bs, offset, bytes);
|
|
break;
|
|
default:
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Forwards an already correctly aligned write request to the BlockDriver,
|
|
* after possibly fragmenting it.
|
|
*/
|
|
static int coroutine_fn bdrv_aligned_pwritev(BdrvChild *child,
|
|
BdrvTrackedRequest *req, int64_t offset, unsigned int bytes,
|
|
int64_t align, QEMUIOVector *qiov, size_t qiov_offset, int flags)
|
|
{
|
|
BlockDriverState *bs = child->bs;
|
|
BlockDriver *drv = bs->drv;
|
|
int ret;
|
|
|
|
uint64_t bytes_remaining = bytes;
|
|
int max_transfer;
|
|
|
|
if (!drv) {
|
|
return -ENOMEDIUM;
|
|
}
|
|
|
|
if (bdrv_has_readonly_bitmaps(bs)) {
|
|
return -EPERM;
|
|
}
|
|
|
|
assert(is_power_of_2(align));
|
|
assert((offset & (align - 1)) == 0);
|
|
assert((bytes & (align - 1)) == 0);
|
|
assert(!qiov || qiov_offset + bytes <= qiov->size);
|
|
max_transfer = QEMU_ALIGN_DOWN(MIN_NON_ZERO(bs->bl.max_transfer, INT_MAX),
|
|
align);
|
|
|
|
ret = bdrv_co_write_req_prepare(child, offset, bytes, req, flags);
|
|
|
|
if (!ret && bs->detect_zeroes != BLOCKDEV_DETECT_ZEROES_OPTIONS_OFF &&
|
|
!(flags & BDRV_REQ_ZERO_WRITE) && drv->bdrv_co_pwrite_zeroes &&
|
|
qemu_iovec_is_zero(qiov, qiov_offset, bytes)) {
|
|
flags |= BDRV_REQ_ZERO_WRITE;
|
|
if (bs->detect_zeroes == BLOCKDEV_DETECT_ZEROES_OPTIONS_UNMAP) {
|
|
flags |= BDRV_REQ_MAY_UNMAP;
|
|
}
|
|
}
|
|
|
|
if (ret < 0) {
|
|
/* Do nothing, write notifier decided to fail this request */
|
|
} else if (flags & BDRV_REQ_ZERO_WRITE) {
|
|
bdrv_debug_event(bs, BLKDBG_PWRITEV_ZERO);
|
|
ret = bdrv_co_do_pwrite_zeroes(bs, offset, bytes, flags);
|
|
} else if (flags & BDRV_REQ_WRITE_COMPRESSED) {
|
|
ret = bdrv_driver_pwritev_compressed(bs, offset, bytes,
|
|
qiov, qiov_offset);
|
|
} else if (bytes <= max_transfer) {
|
|
bdrv_debug_event(bs, BLKDBG_PWRITEV);
|
|
ret = bdrv_driver_pwritev(bs, offset, bytes, qiov, qiov_offset, flags);
|
|
} else {
|
|
bdrv_debug_event(bs, BLKDBG_PWRITEV);
|
|
while (bytes_remaining) {
|
|
int num = MIN(bytes_remaining, max_transfer);
|
|
int local_flags = flags;
|
|
|
|
assert(num);
|
|
if (num < bytes_remaining && (flags & BDRV_REQ_FUA) &&
|
|
!(bs->supported_write_flags & BDRV_REQ_FUA)) {
|
|
/* If FUA is going to be emulated by flush, we only
|
|
* need to flush on the last iteration */
|
|
local_flags &= ~BDRV_REQ_FUA;
|
|
}
|
|
|
|
ret = bdrv_driver_pwritev(bs, offset + bytes - bytes_remaining,
|
|
num, qiov,
|
|
qiov_offset + bytes - bytes_remaining,
|
|
local_flags);
|
|
if (ret < 0) {
|
|
break;
|
|
}
|
|
bytes_remaining -= num;
|
|
}
|
|
}
|
|
bdrv_debug_event(bs, BLKDBG_PWRITEV_DONE);
|
|
|
|
if (ret >= 0) {
|
|
ret = 0;
|
|
}
|
|
bdrv_co_write_req_finish(child, offset, bytes, req, ret);
|
|
|
|
return ret;
|
|
}
|
|
|
|
static int coroutine_fn bdrv_co_do_zero_pwritev(BdrvChild *child,
|
|
int64_t offset,
|
|
unsigned int bytes,
|
|
BdrvRequestFlags flags,
|
|
BdrvTrackedRequest *req)
|
|
{
|
|
BlockDriverState *bs = child->bs;
|
|
QEMUIOVector local_qiov;
|
|
uint64_t align = bs->bl.request_alignment;
|
|
int ret = 0;
|
|
bool padding;
|
|
BdrvRequestPadding pad;
|
|
|
|
padding = bdrv_init_padding(bs, offset, bytes, &pad);
|
|
if (padding) {
|
|
bdrv_mark_request_serialising(req, align);
|
|
|
|
bdrv_padding_rmw_read(child, req, &pad, true);
|
|
|
|
if (pad.head || pad.merge_reads) {
|
|
int64_t aligned_offset = offset & ~(align - 1);
|
|
int64_t write_bytes = pad.merge_reads ? pad.buf_len : align;
|
|
|
|
qemu_iovec_init_buf(&local_qiov, pad.buf, write_bytes);
|
|
ret = bdrv_aligned_pwritev(child, req, aligned_offset, write_bytes,
|
|
align, &local_qiov, 0,
|
|
flags & ~BDRV_REQ_ZERO_WRITE);
|
|
if (ret < 0 || pad.merge_reads) {
|
|
/* Error or all work is done */
|
|
goto out;
|
|
}
|
|
offset += write_bytes - pad.head;
|
|
bytes -= write_bytes - pad.head;
|
|
}
|
|
}
|
|
|
|
assert(!bytes || (offset & (align - 1)) == 0);
|
|
if (bytes >= align) {
|
|
/* Write the aligned part in the middle. */
|
|
uint64_t aligned_bytes = bytes & ~(align - 1);
|
|
ret = bdrv_aligned_pwritev(child, req, offset, aligned_bytes, align,
|
|
NULL, 0, flags);
|
|
if (ret < 0) {
|
|
goto out;
|
|
}
|
|
bytes -= aligned_bytes;
|
|
offset += aligned_bytes;
|
|
}
|
|
|
|
assert(!bytes || (offset & (align - 1)) == 0);
|
|
if (bytes) {
|
|
assert(align == pad.tail + bytes);
|
|
|
|
qemu_iovec_init_buf(&local_qiov, pad.tail_buf, align);
|
|
ret = bdrv_aligned_pwritev(child, req, offset, align, align,
|
|
&local_qiov, 0,
|
|
flags & ~BDRV_REQ_ZERO_WRITE);
|
|
}
|
|
|
|
out:
|
|
bdrv_padding_destroy(&pad);
|
|
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* Handle a write request in coroutine context
|
|
*/
|
|
int coroutine_fn bdrv_co_pwritev(BdrvChild *child,
|
|
int64_t offset, unsigned int bytes, QEMUIOVector *qiov,
|
|
BdrvRequestFlags flags)
|
|
{
|
|
return bdrv_co_pwritev_part(child, offset, bytes, qiov, 0, flags);
|
|
}
|
|
|
|
int coroutine_fn bdrv_co_pwritev_part(BdrvChild *child,
|
|
int64_t offset, unsigned int bytes, QEMUIOVector *qiov, size_t qiov_offset,
|
|
BdrvRequestFlags flags)
|
|
{
|
|
BlockDriverState *bs = child->bs;
|
|
BdrvTrackedRequest req;
|
|
uint64_t align = bs->bl.request_alignment;
|
|
BdrvRequestPadding pad;
|
|
int ret;
|
|
|
|
trace_bdrv_co_pwritev(child->bs, offset, bytes, flags);
|
|
|
|
if (!bs->drv) {
|
|
return -ENOMEDIUM;
|
|
}
|
|
|
|
ret = bdrv_check_byte_request(bs, offset, bytes);
|
|
if (ret < 0) {
|
|
return ret;
|
|
}
|
|
|
|
/* If the request is misaligned then we can't make it efficient */
|
|
if ((flags & BDRV_REQ_NO_FALLBACK) &&
|
|
!QEMU_IS_ALIGNED(offset | bytes, align))
|
|
{
|
|
return -ENOTSUP;
|
|
}
|
|
|
|
if (bytes == 0 && !QEMU_IS_ALIGNED(offset, bs->bl.request_alignment)) {
|
|
/*
|
|
* Aligning zero request is nonsense. Even if driver has special meaning
|
|
* of zero-length (like qcow2_co_pwritev_compressed_part), we can't pass
|
|
* it to driver due to request_alignment.
|
|
*
|
|
* Still, no reason to return an error if someone do unaligned
|
|
* zero-length write occasionally.
|
|
*/
|
|
return 0;
|
|
}
|
|
|
|
bdrv_inc_in_flight(bs);
|
|
/*
|
|
* Align write if necessary by performing a read-modify-write cycle.
|
|
* Pad qiov with the read parts and be sure to have a tracked request not
|
|
* only for bdrv_aligned_pwritev, but also for the reads of the RMW cycle.
|
|
*/
|
|
tracked_request_begin(&req, bs, offset, bytes, BDRV_TRACKED_WRITE);
|
|
|
|
if (flags & BDRV_REQ_ZERO_WRITE) {
|
|
ret = bdrv_co_do_zero_pwritev(child, offset, bytes, flags, &req);
|
|
goto out;
|
|
}
|
|
|
|
if (bdrv_pad_request(bs, &qiov, &qiov_offset, &offset, &bytes, &pad)) {
|
|
bdrv_mark_request_serialising(&req, align);
|
|
bdrv_padding_rmw_read(child, &req, &pad, false);
|
|
}
|
|
|
|
ret = bdrv_aligned_pwritev(child, &req, offset, bytes, align,
|
|
qiov, qiov_offset, flags);
|
|
|
|
bdrv_padding_destroy(&pad);
|
|
|
|
out:
|
|
tracked_request_end(&req);
|
|
bdrv_dec_in_flight(bs);
|
|
|
|
return ret;
|
|
}
|
|
|
|
int coroutine_fn bdrv_co_pwrite_zeroes(BdrvChild *child, int64_t offset,
|
|
int bytes, BdrvRequestFlags flags)
|
|
{
|
|
trace_bdrv_co_pwrite_zeroes(child->bs, offset, bytes, flags);
|
|
|
|
if (!(child->bs->open_flags & BDRV_O_UNMAP)) {
|
|
flags &= ~BDRV_REQ_MAY_UNMAP;
|
|
}
|
|
|
|
return bdrv_co_pwritev(child, offset, bytes, NULL,
|
|
BDRV_REQ_ZERO_WRITE | flags);
|
|
}
|
|
|
|
/*
|
|
* Flush ALL BDSes regardless of if they are reachable via a BlkBackend or not.
|
|
*/
|
|
int bdrv_flush_all(void)
|
|
{
|
|
BdrvNextIterator it;
|
|
BlockDriverState *bs = NULL;
|
|
int result = 0;
|
|
|
|
/*
|
|
* bdrv queue is managed by record/replay,
|
|
* creating new flush request for stopping
|
|
* the VM may break the determinism
|
|
*/
|
|
if (replay_events_enabled()) {
|
|
return result;
|
|
}
|
|
|
|
for (bs = bdrv_first(&it); bs; bs = bdrv_next(&it)) {
|
|
AioContext *aio_context = bdrv_get_aio_context(bs);
|
|
int ret;
|
|
|
|
aio_context_acquire(aio_context);
|
|
ret = bdrv_flush(bs);
|
|
if (ret < 0 && !result) {
|
|
result = ret;
|
|
}
|
|
aio_context_release(aio_context);
|
|
}
|
|
|
|
return result;
|
|
}
|
|
|
|
|
|
typedef struct BdrvCoBlockStatusData {
|
|
BlockDriverState *bs;
|
|
BlockDriverState *base;
|
|
bool want_zero;
|
|
int64_t offset;
|
|
int64_t bytes;
|
|
int64_t *pnum;
|
|
int64_t *map;
|
|
BlockDriverState **file;
|
|
} BdrvCoBlockStatusData;
|
|
|
|
/*
|
|
* Returns the allocation status of the specified sectors.
|
|
* Drivers not implementing the functionality are assumed to not support
|
|
* backing files, hence all their sectors are reported as allocated.
|
|
*
|
|
* If 'want_zero' is true, the caller is querying for mapping
|
|
* purposes, with a focus on valid BDRV_BLOCK_OFFSET_VALID, _DATA, and
|
|
* _ZERO where possible; otherwise, the result favors larger 'pnum',
|
|
* with a focus on accurate BDRV_BLOCK_ALLOCATED.
|
|
*
|
|
* If 'offset' is beyond the end of the disk image the return value is
|
|
* BDRV_BLOCK_EOF and 'pnum' is set to 0.
|
|
*
|
|
* 'bytes' is the max value 'pnum' should be set to. If bytes goes
|
|
* beyond the end of the disk image it will be clamped; if 'pnum' is set to
|
|
* the end of the image, then the returned value will include BDRV_BLOCK_EOF.
|
|
*
|
|
* 'pnum' is set to the number of bytes (including and immediately
|
|
* following the specified offset) that are easily known to be in the
|
|
* same allocated/unallocated state. Note that a second call starting
|
|
* at the original offset plus returned pnum may have the same status.
|
|
* The returned value is non-zero on success except at end-of-file.
|
|
*
|
|
* Returns negative errno on failure. Otherwise, if the
|
|
* BDRV_BLOCK_OFFSET_VALID bit is set, 'map' and 'file' (if non-NULL) are
|
|
* set to the host mapping and BDS corresponding to the guest offset.
|
|
*/
|
|
static int coroutine_fn bdrv_co_block_status(BlockDriverState *bs,
|
|
bool want_zero,
|
|
int64_t offset, int64_t bytes,
|
|
int64_t *pnum, int64_t *map,
|
|
BlockDriverState **file)
|
|
{
|
|
int64_t total_size;
|
|
int64_t n; /* bytes */
|
|
int ret;
|
|
int64_t local_map = 0;
|
|
BlockDriverState *local_file = NULL;
|
|
int64_t aligned_offset, aligned_bytes;
|
|
uint32_t align;
|
|
bool has_filtered_child;
|
|
|
|
assert(pnum);
|
|
*pnum = 0;
|
|
total_size = bdrv_getlength(bs);
|
|
if (total_size < 0) {
|
|
ret = total_size;
|
|
goto early_out;
|
|
}
|
|
|
|
if (offset >= total_size) {
|
|
ret = BDRV_BLOCK_EOF;
|
|
goto early_out;
|
|
}
|
|
if (!bytes) {
|
|
ret = 0;
|
|
goto early_out;
|
|
}
|
|
|
|
n = total_size - offset;
|
|
if (n < bytes) {
|
|
bytes = n;
|
|
}
|
|
|
|
/* Must be non-NULL or bdrv_getlength() would have failed */
|
|
assert(bs->drv);
|
|
has_filtered_child = bdrv_filter_child(bs);
|
|
if (!bs->drv->bdrv_co_block_status && !has_filtered_child) {
|
|
*pnum = bytes;
|
|
ret = BDRV_BLOCK_DATA | BDRV_BLOCK_ALLOCATED;
|
|
if (offset + bytes == total_size) {
|
|
ret |= BDRV_BLOCK_EOF;
|
|
}
|
|
if (bs->drv->protocol_name) {
|
|
ret |= BDRV_BLOCK_OFFSET_VALID;
|
|
local_map = offset;
|
|
local_file = bs;
|
|
}
|
|
goto early_out;
|
|
}
|
|
|
|
bdrv_inc_in_flight(bs);
|
|
|
|
/* Round out to request_alignment boundaries */
|
|
align = bs->bl.request_alignment;
|
|
aligned_offset = QEMU_ALIGN_DOWN(offset, align);
|
|
aligned_bytes = ROUND_UP(offset + bytes, align) - aligned_offset;
|
|
|
|
if (bs->drv->bdrv_co_block_status) {
|
|
ret = bs->drv->bdrv_co_block_status(bs, want_zero, aligned_offset,
|
|
aligned_bytes, pnum, &local_map,
|
|
&local_file);
|
|
} else {
|
|
/* Default code for filters */
|
|
|
|
local_file = bdrv_filter_bs(bs);
|
|
assert(local_file);
|
|
|
|
*pnum = aligned_bytes;
|
|
local_map = aligned_offset;
|
|
ret = BDRV_BLOCK_RAW | BDRV_BLOCK_OFFSET_VALID;
|
|
}
|
|
if (ret < 0) {
|
|
*pnum = 0;
|
|
goto out;
|
|
}
|
|
|
|
/*
|
|
* The driver's result must be a non-zero multiple of request_alignment.
|
|
* Clamp pnum and adjust map to original request.
|
|
*/
|
|
assert(*pnum && QEMU_IS_ALIGNED(*pnum, align) &&
|
|
align > offset - aligned_offset);
|
|
if (ret & BDRV_BLOCK_RECURSE) {
|
|
assert(ret & BDRV_BLOCK_DATA);
|
|
assert(ret & BDRV_BLOCK_OFFSET_VALID);
|
|
assert(!(ret & BDRV_BLOCK_ZERO));
|
|
}
|
|
|
|
*pnum -= offset - aligned_offset;
|
|
if (*pnum > bytes) {
|
|
*pnum = bytes;
|
|
}
|
|
if (ret & BDRV_BLOCK_OFFSET_VALID) {
|
|
local_map += offset - aligned_offset;
|
|
}
|
|
|
|
if (ret & BDRV_BLOCK_RAW) {
|
|
assert(ret & BDRV_BLOCK_OFFSET_VALID && local_file);
|
|
ret = bdrv_co_block_status(local_file, want_zero, local_map,
|
|
*pnum, pnum, &local_map, &local_file);
|
|
goto out;
|
|
}
|
|
|
|
if (ret & (BDRV_BLOCK_DATA | BDRV_BLOCK_ZERO)) {
|
|
ret |= BDRV_BLOCK_ALLOCATED;
|
|
} else if (want_zero && bs->drv->supports_backing) {
|
|
BlockDriverState *cow_bs = bdrv_cow_bs(bs);
|
|
|
|
if (cow_bs) {
|
|
int64_t size2 = bdrv_getlength(cow_bs);
|
|
|
|
if (size2 >= 0 && offset >= size2) {
|
|
ret |= BDRV_BLOCK_ZERO;
|
|
}
|
|
} else {
|
|
ret |= BDRV_BLOCK_ZERO;
|
|
}
|
|
}
|
|
|
|
if (want_zero && ret & BDRV_BLOCK_RECURSE &&
|
|
local_file && local_file != bs &&
|
|
(ret & BDRV_BLOCK_DATA) && !(ret & BDRV_BLOCK_ZERO) &&
|
|
(ret & BDRV_BLOCK_OFFSET_VALID)) {
|
|
int64_t file_pnum;
|
|
int ret2;
|
|
|
|
ret2 = bdrv_co_block_status(local_file, want_zero, local_map,
|
|
*pnum, &file_pnum, NULL, NULL);
|
|
if (ret2 >= 0) {
|
|
/* Ignore errors. This is just providing extra information, it
|
|
* is useful but not necessary.
|
|
*/
|
|
if (ret2 & BDRV_BLOCK_EOF &&
|
|
(!file_pnum || ret2 & BDRV_BLOCK_ZERO)) {
|
|
/*
|
|
* It is valid for the format block driver to read
|
|
* beyond the end of the underlying file's current
|
|
* size; such areas read as zero.
|
|
*/
|
|
ret |= BDRV_BLOCK_ZERO;
|
|
} else {
|
|
/* Limit request to the range reported by the protocol driver */
|
|
*pnum = file_pnum;
|
|
ret |= (ret2 & BDRV_BLOCK_ZERO);
|
|
}
|
|
}
|
|
}
|
|
|
|
out:
|
|
bdrv_dec_in_flight(bs);
|
|
if (ret >= 0 && offset + *pnum == total_size) {
|
|
ret |= BDRV_BLOCK_EOF;
|
|
}
|
|
early_out:
|
|
if (file) {
|
|
*file = local_file;
|
|
}
|
|
if (map) {
|
|
*map = local_map;
|
|
}
|
|
return ret;
|
|
}
|
|
|
|
static int coroutine_fn bdrv_co_block_status_above(BlockDriverState *bs,
|
|
BlockDriverState *base,
|
|
bool want_zero,
|
|
int64_t offset,
|
|
int64_t bytes,
|
|
int64_t *pnum,
|
|
int64_t *map,
|
|
BlockDriverState **file)
|
|
{
|
|
BlockDriverState *p;
|
|
int ret = 0;
|
|
bool first = true;
|
|
|
|
assert(bs != base);
|
|
for (p = bs; p != base; p = bdrv_filter_or_cow_bs(p)) {
|
|
ret = bdrv_co_block_status(p, want_zero, offset, bytes, pnum, map,
|
|
file);
|
|
if (ret < 0) {
|
|
break;
|
|
}
|
|
if (ret & BDRV_BLOCK_ZERO && ret & BDRV_BLOCK_EOF && !first) {
|
|
/*
|
|
* Reading beyond the end of the file continues to read
|
|
* zeroes, but we can only widen the result to the
|
|
* unallocated length we learned from an earlier
|
|
* iteration.
|
|
*/
|
|
*pnum = bytes;
|
|
}
|
|
if (ret & (BDRV_BLOCK_ZERO | BDRV_BLOCK_DATA)) {
|
|
break;
|
|
}
|
|
/* [offset, pnum] unallocated on this layer, which could be only
|
|
* the first part of [offset, bytes]. */
|
|
bytes = MIN(bytes, *pnum);
|
|
first = false;
|
|
}
|
|
return ret;
|
|
}
|
|
|
|
/* Coroutine wrapper for bdrv_block_status_above() */
|
|
static int coroutine_fn bdrv_block_status_above_co_entry(void *opaque)
|
|
{
|
|
BdrvCoBlockStatusData *data = opaque;
|
|
|
|
return bdrv_co_block_status_above(data->bs, data->base,
|
|
data->want_zero,
|
|
data->offset, data->bytes,
|
|
data->pnum, data->map, data->file);
|
|
}
|
|
|
|
/*
|
|
* Synchronous wrapper around bdrv_co_block_status_above().
|
|
*
|
|
* See bdrv_co_block_status_above() for details.
|
|
*/
|
|
static int bdrv_common_block_status_above(BlockDriverState *bs,
|
|
BlockDriverState *base,
|
|
bool want_zero, int64_t offset,
|
|
int64_t bytes, int64_t *pnum,
|
|
int64_t *map,
|
|
BlockDriverState **file)
|
|
{
|
|
BdrvCoBlockStatusData data = {
|
|
.bs = bs,
|
|
.base = base,
|
|
.want_zero = want_zero,
|
|
.offset = offset,
|
|
.bytes = bytes,
|
|
.pnum = pnum,
|
|
.map = map,
|
|
.file = file,
|
|
};
|
|
|
|
return bdrv_run_co(bs, bdrv_block_status_above_co_entry, &data);
|
|
}
|
|
|
|
int bdrv_block_status_above(BlockDriverState *bs, BlockDriverState *base,
|
|
int64_t offset, int64_t bytes, int64_t *pnum,
|
|
int64_t *map, BlockDriverState **file)
|
|
{
|
|
return bdrv_common_block_status_above(bs, base, true, offset, bytes,
|
|
pnum, map, file);
|
|
}
|
|
|
|
int bdrv_block_status(BlockDriverState *bs, int64_t offset, int64_t bytes,
|
|
int64_t *pnum, int64_t *map, BlockDriverState **file)
|
|
{
|
|
return bdrv_block_status_above(bs, bdrv_filter_or_cow_bs(bs),
|
|
offset, bytes, pnum, map, file);
|
|
}
|
|
|
|
int coroutine_fn bdrv_is_allocated(BlockDriverState *bs, int64_t offset,
|
|
int64_t bytes, int64_t *pnum)
|
|
{
|
|
int ret;
|
|
int64_t dummy;
|
|
|
|
ret = bdrv_common_block_status_above(bs, bdrv_filter_or_cow_bs(bs), false,
|
|
offset, bytes, pnum ? pnum : &dummy,
|
|
NULL, NULL);
|
|
if (ret < 0) {
|
|
return ret;
|
|
}
|
|
return !!(ret & BDRV_BLOCK_ALLOCATED);
|
|
}
|
|
|
|
/*
|
|
* Given an image chain: ... -> [BASE] -> [INTER1] -> [INTER2] -> [TOP]
|
|
*
|
|
* Return 1 if (a prefix of) the given range is allocated in any image
|
|
* between BASE and TOP (BASE is only included if include_base is set).
|
|
* BASE can be NULL to check if the given offset is allocated in any
|
|
* image of the chain. Return 0 otherwise, or negative errno on
|
|
* failure.
|
|
*
|
|
* 'pnum' is set to the number of bytes (including and immediately
|
|
* following the specified offset) that are known to be in the same
|
|
* allocated/unallocated state. Note that a subsequent call starting
|
|
* at 'offset + *pnum' may return the same allocation status (in other
|
|
* words, the result is not necessarily the maximum possible range);
|
|
* but 'pnum' will only be 0 when end of file is reached.
|
|
*
|
|
*/
|
|
int bdrv_is_allocated_above(BlockDriverState *top,
|
|
BlockDriverState *base,
|
|
bool include_base, int64_t offset,
|
|
int64_t bytes, int64_t *pnum)
|
|
{
|
|
BlockDriverState *intermediate;
|
|
int ret;
|
|
int64_t n = bytes;
|
|
|
|
assert(base || !include_base);
|
|
|
|
intermediate = top;
|
|
while (include_base || intermediate != base) {
|
|
int64_t pnum_inter;
|
|
int64_t size_inter;
|
|
|
|
assert(intermediate);
|
|
ret = bdrv_is_allocated(intermediate, offset, bytes, &pnum_inter);
|
|
if (ret < 0) {
|
|
return ret;
|
|
}
|
|
if (ret) {
|
|
*pnum = pnum_inter;
|
|
return 1;
|
|
}
|
|
|
|
size_inter = bdrv_getlength(intermediate);
|
|
if (size_inter < 0) {
|
|
return size_inter;
|
|
}
|
|
if (n > pnum_inter &&
|
|
(intermediate == top || offset + pnum_inter < size_inter)) {
|
|
n = pnum_inter;
|
|
}
|
|
|
|
if (intermediate == base) {
|
|
break;
|
|
}
|
|
|
|
intermediate = bdrv_filter_or_cow_bs(intermediate);
|
|
}
|
|
|
|
*pnum = n;
|
|
return 0;
|
|
}
|
|
|
|
typedef struct BdrvVmstateCo {
|
|
BlockDriverState *bs;
|
|
QEMUIOVector *qiov;
|
|
int64_t pos;
|
|
bool is_read;
|
|
} BdrvVmstateCo;
|
|
|
|
static int coroutine_fn
|
|
bdrv_co_rw_vmstate(BlockDriverState *bs, QEMUIOVector *qiov, int64_t pos,
|
|
bool is_read)
|
|
{
|
|
BlockDriver *drv = bs->drv;
|
|
BlockDriverState *child_bs = bdrv_primary_bs(bs);
|
|
int ret = -ENOTSUP;
|
|
|
|
bdrv_inc_in_flight(bs);
|
|
|
|
if (!drv) {
|
|
ret = -ENOMEDIUM;
|
|
} else if (drv->bdrv_load_vmstate) {
|
|
if (is_read) {
|
|
ret = drv->bdrv_load_vmstate(bs, qiov, pos);
|
|
} else {
|
|
ret = drv->bdrv_save_vmstate(bs, qiov, pos);
|
|
}
|
|
} else if (child_bs) {
|
|
ret = bdrv_co_rw_vmstate(child_bs, qiov, pos, is_read);
|
|
}
|
|
|
|
bdrv_dec_in_flight(bs);
|
|
return ret;
|
|
}
|
|
|
|
static int coroutine_fn bdrv_co_rw_vmstate_entry(void *opaque)
|
|
{
|
|
BdrvVmstateCo *co = opaque;
|
|
|
|
return bdrv_co_rw_vmstate(co->bs, co->qiov, co->pos, co->is_read);
|
|
}
|
|
|
|
static inline int
|
|
bdrv_rw_vmstate(BlockDriverState *bs, QEMUIOVector *qiov, int64_t pos,
|
|
bool is_read)
|
|
{
|
|
BdrvVmstateCo data = {
|
|
.bs = bs,
|
|
.qiov = qiov,
|
|
.pos = pos,
|
|
.is_read = is_read,
|
|
};
|
|
|
|
return bdrv_run_co(bs, bdrv_co_rw_vmstate_entry, &data);
|
|
}
|
|
|
|
int bdrv_save_vmstate(BlockDriverState *bs, const uint8_t *buf,
|
|
int64_t pos, int size)
|
|
{
|
|
QEMUIOVector qiov = QEMU_IOVEC_INIT_BUF(qiov, buf, size);
|
|
int ret;
|
|
|
|
ret = bdrv_writev_vmstate(bs, &qiov, pos);
|
|
if (ret < 0) {
|
|
return ret;
|
|
}
|
|
|
|
return size;
|
|
}
|
|
|
|
int bdrv_writev_vmstate(BlockDriverState *bs, QEMUIOVector *qiov, int64_t pos)
|
|
{
|
|
return bdrv_rw_vmstate(bs, qiov, pos, false);
|
|
}
|
|
|
|
int bdrv_load_vmstate(BlockDriverState *bs, uint8_t *buf,
|
|
int64_t pos, int size)
|
|
{
|
|
QEMUIOVector qiov = QEMU_IOVEC_INIT_BUF(qiov, buf, size);
|
|
int ret;
|
|
|
|
ret = bdrv_readv_vmstate(bs, &qiov, pos);
|
|
if (ret < 0) {
|
|
return ret;
|
|
}
|
|
|
|
return size;
|
|
}
|
|
|
|
int bdrv_readv_vmstate(BlockDriverState *bs, QEMUIOVector *qiov, int64_t pos)
|
|
{
|
|
return bdrv_rw_vmstate(bs, qiov, pos, true);
|
|
}
|
|
|
|
/**************************************************************/
|
|
/* async I/Os */
|
|
|
|
void bdrv_aio_cancel(BlockAIOCB *acb)
|
|
{
|
|
qemu_aio_ref(acb);
|
|
bdrv_aio_cancel_async(acb);
|
|
while (acb->refcnt > 1) {
|
|
if (acb->aiocb_info->get_aio_context) {
|
|
aio_poll(acb->aiocb_info->get_aio_context(acb), true);
|
|
} else if (acb->bs) {
|
|
/* qemu_aio_ref and qemu_aio_unref are not thread-safe, so
|
|
* assert that we're not using an I/O thread. Thread-safe
|
|
* code should use bdrv_aio_cancel_async exclusively.
|
|
*/
|
|
assert(bdrv_get_aio_context(acb->bs) == qemu_get_aio_context());
|
|
aio_poll(bdrv_get_aio_context(acb->bs), true);
|
|
} else {
|
|
abort();
|
|
}
|
|
}
|
|
qemu_aio_unref(acb);
|
|
}
|
|
|
|
/* Async version of aio cancel. The caller is not blocked if the acb implements
|
|
* cancel_async, otherwise we do nothing and let the request normally complete.
|
|
* In either case the completion callback must be called. */
|
|
void bdrv_aio_cancel_async(BlockAIOCB *acb)
|
|
{
|
|
if (acb->aiocb_info->cancel_async) {
|
|
acb->aiocb_info->cancel_async(acb);
|
|
}
|
|
}
|
|
|
|
/**************************************************************/
|
|
/* Coroutine block device emulation */
|
|
|
|
static int coroutine_fn bdrv_flush_co_entry(void *opaque)
|
|
{
|
|
return bdrv_co_flush(opaque);
|
|
}
|
|
|
|
int coroutine_fn bdrv_co_flush(BlockDriverState *bs)
|
|
{
|
|
BdrvChild *primary_child = bdrv_primary_child(bs);
|
|
BdrvChild *child;
|
|
int current_gen;
|
|
int ret = 0;
|
|
|
|
bdrv_inc_in_flight(bs);
|
|
|
|
if (!bdrv_is_inserted(bs) || bdrv_is_read_only(bs) ||
|
|
bdrv_is_sg(bs)) {
|
|
goto early_exit;
|
|
}
|
|
|
|
qemu_co_mutex_lock(&bs->reqs_lock);
|
|
current_gen = qatomic_read(&bs->write_gen);
|
|
|
|
/* Wait until any previous flushes are completed */
|
|
while (bs->active_flush_req) {
|
|
qemu_co_queue_wait(&bs->flush_queue, &bs->reqs_lock);
|
|
}
|
|
|
|
/* Flushes reach this point in nondecreasing current_gen order. */
|
|
bs->active_flush_req = true;
|
|
qemu_co_mutex_unlock(&bs->reqs_lock);
|
|
|
|
/* Write back all layers by calling one driver function */
|
|
if (bs->drv->bdrv_co_flush) {
|
|
ret = bs->drv->bdrv_co_flush(bs);
|
|
goto out;
|
|
}
|
|
|
|
/* Write back cached data to the OS even with cache=unsafe */
|
|
BLKDBG_EVENT(primary_child, BLKDBG_FLUSH_TO_OS);
|
|
if (bs->drv->bdrv_co_flush_to_os) {
|
|
ret = bs->drv->bdrv_co_flush_to_os(bs);
|
|
if (ret < 0) {
|
|
goto out;
|
|
}
|
|
}
|
|
|
|
/* But don't actually force it to the disk with cache=unsafe */
|
|
if (bs->open_flags & BDRV_O_NO_FLUSH) {
|
|
goto flush_children;
|
|
}
|
|
|
|
/* Check if we really need to flush anything */
|
|
if (bs->flushed_gen == current_gen) {
|
|
goto flush_children;
|
|
}
|
|
|
|
BLKDBG_EVENT(primary_child, BLKDBG_FLUSH_TO_DISK);
|
|
if (!bs->drv) {
|
|
/* bs->drv->bdrv_co_flush() might have ejected the BDS
|
|
* (even in case of apparent success) */
|
|
ret = -ENOMEDIUM;
|
|
goto out;
|
|
}
|
|
if (bs->drv->bdrv_co_flush_to_disk) {
|
|
ret = bs->drv->bdrv_co_flush_to_disk(bs);
|
|
} else if (bs->drv->bdrv_aio_flush) {
|
|
BlockAIOCB *acb;
|
|
CoroutineIOCompletion co = {
|
|
.coroutine = qemu_coroutine_self(),
|
|
};
|
|
|
|
acb = bs->drv->bdrv_aio_flush(bs, bdrv_co_io_em_complete, &co);
|
|
if (acb == NULL) {
|
|
ret = -EIO;
|
|
} else {
|
|
qemu_coroutine_yield();
|
|
ret = co.ret;
|
|
}
|
|
} else {
|
|
/*
|
|
* Some block drivers always operate in either writethrough or unsafe
|
|
* mode and don't support bdrv_flush therefore. Usually qemu doesn't
|
|
* know how the server works (because the behaviour is hardcoded or
|
|
* depends on server-side configuration), so we can't ensure that
|
|
* everything is safe on disk. Returning an error doesn't work because
|
|
* that would break guests even if the server operates in writethrough
|
|
* mode.
|
|
*
|
|
* Let's hope the user knows what he's doing.
|
|
*/
|
|
ret = 0;
|
|
}
|
|
|
|
if (ret < 0) {
|
|
goto out;
|
|
}
|
|
|
|
/* Now flush the underlying protocol. It will also have BDRV_O_NO_FLUSH
|
|
* in the case of cache=unsafe, so there are no useless flushes.
|
|
*/
|
|
flush_children:
|
|
ret = 0;
|
|
QLIST_FOREACH(child, &bs->children, next) {
|
|
if (child->perm & (BLK_PERM_WRITE | BLK_PERM_WRITE_UNCHANGED)) {
|
|
int this_child_ret = bdrv_co_flush(child->bs);
|
|
if (!ret) {
|
|
ret = this_child_ret;
|
|
}
|
|
}
|
|
}
|
|
|
|
out:
|
|
/* Notify any pending flushes that we have completed */
|
|
if (ret == 0) {
|
|
bs->flushed_gen = current_gen;
|
|
}
|
|
|
|
qemu_co_mutex_lock(&bs->reqs_lock);
|
|
bs->active_flush_req = false;
|
|
/* Return value is ignored - it's ok if wait queue is empty */
|
|
qemu_co_queue_next(&bs->flush_queue);
|
|
qemu_co_mutex_unlock(&bs->reqs_lock);
|
|
|
|
early_exit:
|
|
bdrv_dec_in_flight(bs);
|
|
return ret;
|
|
}
|
|
|
|
int bdrv_flush(BlockDriverState *bs)
|
|
{
|
|
return bdrv_run_co(bs, bdrv_flush_co_entry, bs);
|
|
}
|
|
|
|
typedef struct DiscardCo {
|
|
BdrvChild *child;
|
|
int64_t offset;
|
|
int64_t bytes;
|
|
} DiscardCo;
|
|
|
|
static int coroutine_fn bdrv_pdiscard_co_entry(void *opaque)
|
|
{
|
|
DiscardCo *rwco = opaque;
|
|
|
|
return bdrv_co_pdiscard(rwco->child, rwco->offset, rwco->bytes);
|
|
}
|
|
|
|
int coroutine_fn bdrv_co_pdiscard(BdrvChild *child, int64_t offset,
|
|
int64_t bytes)
|
|
{
|
|
BdrvTrackedRequest req;
|
|
int max_pdiscard, ret;
|
|
int head, tail, align;
|
|
BlockDriverState *bs = child->bs;
|
|
|
|
if (!bs || !bs->drv || !bdrv_is_inserted(bs)) {
|
|
return -ENOMEDIUM;
|
|
}
|
|
|
|
if (bdrv_has_readonly_bitmaps(bs)) {
|
|
return -EPERM;
|
|
}
|
|
|
|
if (offset < 0 || bytes < 0 || bytes > INT64_MAX - offset) {
|
|
return -EIO;
|
|
}
|
|
|
|
/* Do nothing if disabled. */
|
|
if (!(bs->open_flags & BDRV_O_UNMAP)) {
|
|
return 0;
|
|
}
|
|
|
|
if (!bs->drv->bdrv_co_pdiscard && !bs->drv->bdrv_aio_pdiscard) {
|
|
return 0;
|
|
}
|
|
|
|
/* Discard is advisory, but some devices track and coalesce
|
|
* unaligned requests, so we must pass everything down rather than
|
|
* round here. Still, most devices will just silently ignore
|
|
* unaligned requests (by returning -ENOTSUP), so we must fragment
|
|
* the request accordingly. */
|
|
align = MAX(bs->bl.pdiscard_alignment, bs->bl.request_alignment);
|
|
assert(align % bs->bl.request_alignment == 0);
|
|
head = offset % align;
|
|
tail = (offset + bytes) % align;
|
|
|
|
bdrv_inc_in_flight(bs);
|
|
tracked_request_begin(&req, bs, offset, bytes, BDRV_TRACKED_DISCARD);
|
|
|
|
ret = bdrv_co_write_req_prepare(child, offset, bytes, &req, 0);
|
|
if (ret < 0) {
|
|
goto out;
|
|
}
|
|
|
|
max_pdiscard = QEMU_ALIGN_DOWN(MIN_NON_ZERO(bs->bl.max_pdiscard, INT_MAX),
|
|
align);
|
|
assert(max_pdiscard >= bs->bl.request_alignment);
|
|
|
|
while (bytes > 0) {
|
|
int64_t num = bytes;
|
|
|
|
if (head) {
|
|
/* Make small requests to get to alignment boundaries. */
|
|
num = MIN(bytes, align - head);
|
|
if (!QEMU_IS_ALIGNED(num, bs->bl.request_alignment)) {
|
|
num %= bs->bl.request_alignment;
|
|
}
|
|
head = (head + num) % align;
|
|
assert(num < max_pdiscard);
|
|
} else if (tail) {
|
|
if (num > align) {
|
|
/* Shorten the request to the last aligned cluster. */
|
|
num -= tail;
|
|
} else if (!QEMU_IS_ALIGNED(tail, bs->bl.request_alignment) &&
|
|
tail > bs->bl.request_alignment) {
|
|
tail %= bs->bl.request_alignment;
|
|
num -= tail;
|
|
}
|
|
}
|
|
/* limit request size */
|
|
if (num > max_pdiscard) {
|
|
num = max_pdiscard;
|
|
}
|
|
|
|
if (!bs->drv) {
|
|
ret = -ENOMEDIUM;
|
|
goto out;
|
|
}
|
|
if (bs->drv->bdrv_co_pdiscard) {
|
|
ret = bs->drv->bdrv_co_pdiscard(bs, offset, num);
|
|
} else {
|
|
BlockAIOCB *acb;
|
|
CoroutineIOCompletion co = {
|
|
.coroutine = qemu_coroutine_self(),
|
|
};
|
|
|
|
acb = bs->drv->bdrv_aio_pdiscard(bs, offset, num,
|
|
bdrv_co_io_em_complete, &co);
|
|
if (acb == NULL) {
|
|
ret = -EIO;
|
|
goto out;
|
|
} else {
|
|
qemu_coroutine_yield();
|
|
ret = co.ret;
|
|
}
|
|
}
|
|
if (ret && ret != -ENOTSUP) {
|
|
goto out;
|
|
}
|
|
|
|
offset += num;
|
|
bytes -= num;
|
|
}
|
|
ret = 0;
|
|
out:
|
|
bdrv_co_write_req_finish(child, req.offset, req.bytes, &req, ret);
|
|
tracked_request_end(&req);
|
|
bdrv_dec_in_flight(bs);
|
|
return ret;
|
|
}
|
|
|
|
int bdrv_pdiscard(BdrvChild *child, int64_t offset, int64_t bytes)
|
|
{
|
|
DiscardCo rwco = {
|
|
.child = child,
|
|
.offset = offset,
|
|
.bytes = bytes,
|
|
};
|
|
|
|
return bdrv_run_co(child->bs, bdrv_pdiscard_co_entry, &rwco);
|
|
}
|
|
|
|
int bdrv_co_ioctl(BlockDriverState *bs, int req, void *buf)
|
|
{
|
|
BlockDriver *drv = bs->drv;
|
|
CoroutineIOCompletion co = {
|
|
.coroutine = qemu_coroutine_self(),
|
|
};
|
|
BlockAIOCB *acb;
|
|
|
|
bdrv_inc_in_flight(bs);
|
|
if (!drv || (!drv->bdrv_aio_ioctl && !drv->bdrv_co_ioctl)) {
|
|
co.ret = -ENOTSUP;
|
|
goto out;
|
|
}
|
|
|
|
if (drv->bdrv_co_ioctl) {
|
|
co.ret = drv->bdrv_co_ioctl(bs, req, buf);
|
|
} else {
|
|
acb = drv->bdrv_aio_ioctl(bs, req, buf, bdrv_co_io_em_complete, &co);
|
|
if (!acb) {
|
|
co.ret = -ENOTSUP;
|
|
goto out;
|
|
}
|
|
qemu_coroutine_yield();
|
|
}
|
|
out:
|
|
bdrv_dec_in_flight(bs);
|
|
return co.ret;
|
|
}
|
|
|
|
void *qemu_blockalign(BlockDriverState *bs, size_t size)
|
|
{
|
|
return qemu_memalign(bdrv_opt_mem_align(bs), size);
|
|
}
|
|
|
|
void *qemu_blockalign0(BlockDriverState *bs, size_t size)
|
|
{
|
|
return memset(qemu_blockalign(bs, size), 0, size);
|
|
}
|
|
|
|
void *qemu_try_blockalign(BlockDriverState *bs, size_t size)
|
|
{
|
|
size_t align = bdrv_opt_mem_align(bs);
|
|
|
|
/* Ensure that NULL is never returned on success */
|
|
assert(align > 0);
|
|
if (size == 0) {
|
|
size = align;
|
|
}
|
|
|
|
return qemu_try_memalign(align, size);
|
|
}
|
|
|
|
void *qemu_try_blockalign0(BlockDriverState *bs, size_t size)
|
|
{
|
|
void *mem = qemu_try_blockalign(bs, size);
|
|
|
|
if (mem) {
|
|
memset(mem, 0, size);
|
|
}
|
|
|
|
return mem;
|
|
}
|
|
|
|
/*
|
|
* Check if all memory in this vector is sector aligned.
|
|
*/
|
|
bool bdrv_qiov_is_aligned(BlockDriverState *bs, QEMUIOVector *qiov)
|
|
{
|
|
int i;
|
|
size_t alignment = bdrv_min_mem_align(bs);
|
|
|
|
for (i = 0; i < qiov->niov; i++) {
|
|
if ((uintptr_t) qiov->iov[i].iov_base % alignment) {
|
|
return false;
|
|
}
|
|
if (qiov->iov[i].iov_len % alignment) {
|
|
return false;
|
|
}
|
|
}
|
|
|
|
return true;
|
|
}
|
|
|
|
void bdrv_add_before_write_notifier(BlockDriverState *bs,
|
|
NotifierWithReturn *notifier)
|
|
{
|
|
notifier_with_return_list_add(&bs->before_write_notifiers, notifier);
|
|
}
|
|
|
|
void bdrv_io_plug(BlockDriverState *bs)
|
|
{
|
|
BdrvChild *child;
|
|
|
|
QLIST_FOREACH(child, &bs->children, next) {
|
|
bdrv_io_plug(child->bs);
|
|
}
|
|
|
|
if (qatomic_fetch_inc(&bs->io_plugged) == 0) {
|
|
BlockDriver *drv = bs->drv;
|
|
if (drv && drv->bdrv_io_plug) {
|
|
drv->bdrv_io_plug(bs);
|
|
}
|
|
}
|
|
}
|
|
|
|
void bdrv_io_unplug(BlockDriverState *bs)
|
|
{
|
|
BdrvChild *child;
|
|
|
|
assert(bs->io_plugged);
|
|
if (qatomic_fetch_dec(&bs->io_plugged) == 1) {
|
|
BlockDriver *drv = bs->drv;
|
|
if (drv && drv->bdrv_io_unplug) {
|
|
drv->bdrv_io_unplug(bs);
|
|
}
|
|
}
|
|
|
|
QLIST_FOREACH(child, &bs->children, next) {
|
|
bdrv_io_unplug(child->bs);
|
|
}
|
|
}
|
|
|
|
void bdrv_register_buf(BlockDriverState *bs, void *host, size_t size)
|
|
{
|
|
BdrvChild *child;
|
|
|
|
if (bs->drv && bs->drv->bdrv_register_buf) {
|
|
bs->drv->bdrv_register_buf(bs, host, size);
|
|
}
|
|
QLIST_FOREACH(child, &bs->children, next) {
|
|
bdrv_register_buf(child->bs, host, size);
|
|
}
|
|
}
|
|
|
|
void bdrv_unregister_buf(BlockDriverState *bs, void *host)
|
|
{
|
|
BdrvChild *child;
|
|
|
|
if (bs->drv && bs->drv->bdrv_unregister_buf) {
|
|
bs->drv->bdrv_unregister_buf(bs, host);
|
|
}
|
|
QLIST_FOREACH(child, &bs->children, next) {
|
|
bdrv_unregister_buf(child->bs, host);
|
|
}
|
|
}
|
|
|
|
static int coroutine_fn bdrv_co_copy_range_internal(
|
|
BdrvChild *src, uint64_t src_offset, BdrvChild *dst,
|
|
uint64_t dst_offset, uint64_t bytes,
|
|
BdrvRequestFlags read_flags, BdrvRequestFlags write_flags,
|
|
bool recurse_src)
|
|
{
|
|
BdrvTrackedRequest req;
|
|
int ret;
|
|
|
|
/* TODO We can support BDRV_REQ_NO_FALLBACK here */
|
|
assert(!(read_flags & BDRV_REQ_NO_FALLBACK));
|
|
assert(!(write_flags & BDRV_REQ_NO_FALLBACK));
|
|
|
|
if (!dst || !dst->bs) {
|
|
return -ENOMEDIUM;
|
|
}
|
|
ret = bdrv_check_byte_request(dst->bs, dst_offset, bytes);
|
|
if (ret) {
|
|
return ret;
|
|
}
|
|
if (write_flags & BDRV_REQ_ZERO_WRITE) {
|
|
return bdrv_co_pwrite_zeroes(dst, dst_offset, bytes, write_flags);
|
|
}
|
|
|
|
if (!src || !src->bs) {
|
|
return -ENOMEDIUM;
|
|
}
|
|
ret = bdrv_check_byte_request(src->bs, src_offset, bytes);
|
|
if (ret) {
|
|
return ret;
|
|
}
|
|
|
|
if (!src->bs->drv->bdrv_co_copy_range_from
|
|
|| !dst->bs->drv->bdrv_co_copy_range_to
|
|
|| src->bs->encrypted || dst->bs->encrypted) {
|
|
return -ENOTSUP;
|
|
}
|
|
|
|
if (recurse_src) {
|
|
bdrv_inc_in_flight(src->bs);
|
|
tracked_request_begin(&req, src->bs, src_offset, bytes,
|
|
BDRV_TRACKED_READ);
|
|
|
|
/* BDRV_REQ_SERIALISING is only for write operation */
|
|
assert(!(read_flags & BDRV_REQ_SERIALISING));
|
|
bdrv_wait_serialising_requests(&req);
|
|
|
|
ret = src->bs->drv->bdrv_co_copy_range_from(src->bs,
|
|
src, src_offset,
|
|
dst, dst_offset,
|
|
bytes,
|
|
read_flags, write_flags);
|
|
|
|
tracked_request_end(&req);
|
|
bdrv_dec_in_flight(src->bs);
|
|
} else {
|
|
bdrv_inc_in_flight(dst->bs);
|
|
tracked_request_begin(&req, dst->bs, dst_offset, bytes,
|
|
BDRV_TRACKED_WRITE);
|
|
ret = bdrv_co_write_req_prepare(dst, dst_offset, bytes, &req,
|
|
write_flags);
|
|
if (!ret) {
|
|
ret = dst->bs->drv->bdrv_co_copy_range_to(dst->bs,
|
|
src, src_offset,
|
|
dst, dst_offset,
|
|
bytes,
|
|
read_flags, write_flags);
|
|
}
|
|
bdrv_co_write_req_finish(dst, dst_offset, bytes, &req, ret);
|
|
tracked_request_end(&req);
|
|
bdrv_dec_in_flight(dst->bs);
|
|
}
|
|
|
|
return ret;
|
|
}
|
|
|
|
/* Copy range from @src to @dst.
|
|
*
|
|
* See the comment of bdrv_co_copy_range for the parameter and return value
|
|
* semantics. */
|
|
int coroutine_fn bdrv_co_copy_range_from(BdrvChild *src, uint64_t src_offset,
|
|
BdrvChild *dst, uint64_t dst_offset,
|
|
uint64_t bytes,
|
|
BdrvRequestFlags read_flags,
|
|
BdrvRequestFlags write_flags)
|
|
{
|
|
trace_bdrv_co_copy_range_from(src, src_offset, dst, dst_offset, bytes,
|
|
read_flags, write_flags);
|
|
return bdrv_co_copy_range_internal(src, src_offset, dst, dst_offset,
|
|
bytes, read_flags, write_flags, true);
|
|
}
|
|
|
|
/* Copy range from @src to @dst.
|
|
*
|
|
* See the comment of bdrv_co_copy_range for the parameter and return value
|
|
* semantics. */
|
|
int coroutine_fn bdrv_co_copy_range_to(BdrvChild *src, uint64_t src_offset,
|
|
BdrvChild *dst, uint64_t dst_offset,
|
|
uint64_t bytes,
|
|
BdrvRequestFlags read_flags,
|
|
BdrvRequestFlags write_flags)
|
|
{
|
|
trace_bdrv_co_copy_range_to(src, src_offset, dst, dst_offset, bytes,
|
|
read_flags, write_flags);
|
|
return bdrv_co_copy_range_internal(src, src_offset, dst, dst_offset,
|
|
bytes, read_flags, write_flags, false);
|
|
}
|
|
|
|
int coroutine_fn bdrv_co_copy_range(BdrvChild *src, uint64_t src_offset,
|
|
BdrvChild *dst, uint64_t dst_offset,
|
|
uint64_t bytes, BdrvRequestFlags read_flags,
|
|
BdrvRequestFlags write_flags)
|
|
{
|
|
return bdrv_co_copy_range_from(src, src_offset,
|
|
dst, dst_offset,
|
|
bytes, read_flags, write_flags);
|
|
}
|
|
|
|
static void bdrv_parent_cb_resize(BlockDriverState *bs)
|
|
{
|
|
BdrvChild *c;
|
|
QLIST_FOREACH(c, &bs->parents, next_parent) {
|
|
if (c->klass->resize) {
|
|
c->klass->resize(c);
|
|
}
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Truncate file to 'offset' bytes (needed only for file protocols)
|
|
*
|
|
* If 'exact' is true, the file must be resized to exactly the given
|
|
* 'offset'. Otherwise, it is sufficient for the node to be at least
|
|
* 'offset' bytes in length.
|
|
*/
|
|
int coroutine_fn bdrv_co_truncate(BdrvChild *child, int64_t offset, bool exact,
|
|
PreallocMode prealloc, BdrvRequestFlags flags,
|
|
Error **errp)
|
|
{
|
|
BlockDriverState *bs = child->bs;
|
|
BdrvChild *filtered, *backing;
|
|
BlockDriver *drv = bs->drv;
|
|
BdrvTrackedRequest req;
|
|
int64_t old_size, new_bytes;
|
|
int ret;
|
|
|
|
|
|
/* if bs->drv == NULL, bs is closed, so there's nothing to do here */
|
|
if (!drv) {
|
|
error_setg(errp, "No medium inserted");
|
|
return -ENOMEDIUM;
|
|
}
|
|
if (offset < 0) {
|
|
error_setg(errp, "Image size cannot be negative");
|
|
return -EINVAL;
|
|
}
|
|
|
|
old_size = bdrv_getlength(bs);
|
|
if (old_size < 0) {
|
|
error_setg_errno(errp, -old_size, "Failed to get old image size");
|
|
return old_size;
|
|
}
|
|
|
|
if (offset > old_size) {
|
|
new_bytes = offset - old_size;
|
|
} else {
|
|
new_bytes = 0;
|
|
}
|
|
|
|
bdrv_inc_in_flight(bs);
|
|
tracked_request_begin(&req, bs, offset - new_bytes, new_bytes,
|
|
BDRV_TRACKED_TRUNCATE);
|
|
|
|
/* If we are growing the image and potentially using preallocation for the
|
|
* new area, we need to make sure that no write requests are made to it
|
|
* concurrently or they might be overwritten by preallocation. */
|
|
if (new_bytes) {
|
|
bdrv_mark_request_serialising(&req, 1);
|
|
}
|
|
if (bs->read_only) {
|
|
error_setg(errp, "Image is read-only");
|
|
ret = -EACCES;
|
|
goto out;
|
|
}
|
|
ret = bdrv_co_write_req_prepare(child, offset - new_bytes, new_bytes, &req,
|
|
0);
|
|
if (ret < 0) {
|
|
error_setg_errno(errp, -ret,
|
|
"Failed to prepare request for truncation");
|
|
goto out;
|
|
}
|
|
|
|
filtered = bdrv_filter_child(bs);
|
|
backing = bdrv_cow_child(bs);
|
|
|
|
/*
|
|
* If the image has a backing file that is large enough that it would
|
|
* provide data for the new area, we cannot leave it unallocated because
|
|
* then the backing file content would become visible. Instead, zero-fill
|
|
* the new area.
|
|
*
|
|
* Note that if the image has a backing file, but was opened without the
|
|
* backing file, taking care of keeping things consistent with that backing
|
|
* file is the user's responsibility.
|
|
*/
|
|
if (new_bytes && backing) {
|
|
int64_t backing_len;
|
|
|
|
backing_len = bdrv_getlength(backing->bs);
|
|
if (backing_len < 0) {
|
|
ret = backing_len;
|
|
error_setg_errno(errp, -ret, "Could not get backing file size");
|
|
goto out;
|
|
}
|
|
|
|
if (backing_len > old_size) {
|
|
flags |= BDRV_REQ_ZERO_WRITE;
|
|
}
|
|
}
|
|
|
|
if (drv->bdrv_co_truncate) {
|
|
if (flags & ~bs->supported_truncate_flags) {
|
|
error_setg(errp, "Block driver does not support requested flags");
|
|
ret = -ENOTSUP;
|
|
goto out;
|
|
}
|
|
ret = drv->bdrv_co_truncate(bs, offset, exact, prealloc, flags, errp);
|
|
} else if (filtered) {
|
|
ret = bdrv_co_truncate(filtered, offset, exact, prealloc, flags, errp);
|
|
} else {
|
|
error_setg(errp, "Image format driver does not support resize");
|
|
ret = -ENOTSUP;
|
|
goto out;
|
|
}
|
|
if (ret < 0) {
|
|
goto out;
|
|
}
|
|
|
|
ret = refresh_total_sectors(bs, offset >> BDRV_SECTOR_BITS);
|
|
if (ret < 0) {
|
|
error_setg_errno(errp, -ret, "Could not refresh total sector count");
|
|
} else {
|
|
offset = bs->total_sectors * BDRV_SECTOR_SIZE;
|
|
}
|
|
/* It's possible that truncation succeeded but refresh_total_sectors
|
|
* failed, but the latter doesn't affect how we should finish the request.
|
|
* Pass 0 as the last parameter so that dirty bitmaps etc. are handled. */
|
|
bdrv_co_write_req_finish(child, offset - new_bytes, new_bytes, &req, 0);
|
|
|
|
out:
|
|
tracked_request_end(&req);
|
|
bdrv_dec_in_flight(bs);
|
|
|
|
return ret;
|
|
}
|
|
|
|
typedef struct TruncateCo {
|
|
BdrvChild *child;
|
|
int64_t offset;
|
|
bool exact;
|
|
PreallocMode prealloc;
|
|
BdrvRequestFlags flags;
|
|
Error **errp;
|
|
} TruncateCo;
|
|
|
|
static int coroutine_fn bdrv_truncate_co_entry(void *opaque)
|
|
{
|
|
TruncateCo *tco = opaque;
|
|
|
|
return bdrv_co_truncate(tco->child, tco->offset, tco->exact,
|
|
tco->prealloc, tco->flags, tco->errp);
|
|
}
|
|
|
|
int bdrv_truncate(BdrvChild *child, int64_t offset, bool exact,
|
|
PreallocMode prealloc, BdrvRequestFlags flags, Error **errp)
|
|
{
|
|
TruncateCo tco = {
|
|
.child = child,
|
|
.offset = offset,
|
|
.exact = exact,
|
|
.prealloc = prealloc,
|
|
.flags = flags,
|
|
.errp = errp,
|
|
};
|
|
|
|
return bdrv_run_co(child->bs, bdrv_truncate_co_entry, &tco);
|
|
}
|