iQEcBAABAgAGBQJZbNpiAAoJEJykq7OBq3PIKcIIAMEJpEiWQonSJZVV4fxqcbOF dXJSVxHqrrVUrcM8NY2zGXIwcGS8RBNZG+Yx/SEZgIljoYH4NFmbvKXWS2zgHSyr LUH0M6gYlQ/1vQTXwQrkJdtmgfc3xNVrQbanbynK3+aB1S5Y6pRGauDo8SqCBWu0 uLWkhcSQbG+OHD8Go5X1kZUSdpP8yOqKrxcNLe980ghi4HPMUydL3lbs4SwNlnRt NJIpMTGzJrL+CqyakIL+/PT9RBGCo4hllPD0CgX6HETEkuojxxXaqJIG+Tzj2FeU fXkoK1YQHEHLdVXnPkpModoPylhRqIQcPXoXt+aMvoLSM+bLooYXMYryMPoPDGI= =VgCF -----END PGP SIGNATURE----- Merge remote-tracking branch 'remotes/stefanha/tags/block-pull-request' into staging # gpg: Signature made Mon 17 Jul 2017 16:40:18 BST # gpg: using RSA key 0x9CA4ABB381AB73C8 # gpg: Good signature from "Stefan Hajnoczi <stefanha@redhat.com>" # gpg: aka "Stefan Hajnoczi <stefanha@gmail.com>" # Primary key fingerprint: 8695 A8BF D3F9 7CDA AC35 775A 9CA4 ABB3 81AB 73C8 * remotes/stefanha/tags/block-pull-request: block: fix shadowed variable in bdrv_co_pdiscard util/aio-win32: Only select on what we are actually waiting for Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
2565 lines
75 KiB
C
2565 lines
75 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/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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#define NOT_DONE 0x7fffffff /* used while emulated sync operation in progress */
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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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void bdrv_parent_drained_begin(BlockDriverState *bs)
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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->role->drained_begin) {
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c->role->drained_begin(c);
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}
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}
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}
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void bdrv_parent_drained_end(BlockDriverState *bs)
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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->role->drained_end) {
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c->role->drained_end(c);
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}
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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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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 ? 1 : 512;
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/* Take some limits from the children as a default */
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if (bs->file) {
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bdrv_refresh_limits(bs->file->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, &bs->file->bs->bl);
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} else {
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bs->bl.min_mem_alignment = 512;
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bs->bl.opt_mem_alignment = getpagesize();
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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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if (bs->backing) {
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bdrv_refresh_limits(bs->backing->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, &bs->backing->bs->bl);
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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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atomic_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 = atomic_fetch_dec(&bs->copy_on_read);
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assert(old >= 1);
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}
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/* Check if any requests are in-flight (including throttled requests) */
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bool bdrv_requests_pending(BlockDriverState *bs)
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{
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BdrvChild *child;
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if (atomic_read(&bs->in_flight)) {
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return true;
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}
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QLIST_FOREACH(child, &bs->children, next) {
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if (bdrv_requests_pending(child->bs)) {
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return true;
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}
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}
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return false;
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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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} 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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bs->drv->bdrv_co_drain(bs);
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/* Set data->done before reading bs->wakeup. */
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atomic_mb_set(&data->done, true);
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bdrv_wakeup(bs);
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}
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static void bdrv_drain_invoke(BlockDriverState *bs)
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{
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BdrvCoDrainData data = { .bs = bs, .done = false };
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if (!bs->drv || !bs->drv->bdrv_co_drain) {
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return;
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}
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data.co = qemu_coroutine_create(bdrv_drain_invoke_entry, &data);
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bdrv_coroutine_enter(bs, data.co);
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BDRV_POLL_WHILE(bs, !data.done);
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}
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static bool bdrv_drain_recurse(BlockDriverState *bs)
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{
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BdrvChild *child, *tmp;
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bool waited;
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waited = BDRV_POLL_WHILE(bs, atomic_read(&bs->in_flight) > 0);
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/* Ensure any pending metadata writes are submitted to bs->file. */
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bdrv_drain_invoke(bs);
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QLIST_FOREACH_SAFE(child, &bs->children, next, tmp) {
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BlockDriverState *bs = child->bs;
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bool in_main_loop =
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qemu_get_current_aio_context() == qemu_get_aio_context();
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assert(bs->refcnt > 0);
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if (in_main_loop) {
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/* In case the recursive bdrv_drain_recurse processes a
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* block_job_defer_to_main_loop BH and modifies the graph,
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* let's hold a reference to bs until we are done.
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*
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* IOThread doesn't have such a BH, and it is not safe to call
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* bdrv_unref without BQL, so skip doing it there.
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*/
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bdrv_ref(bs);
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}
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waited |= bdrv_drain_recurse(bs);
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if (in_main_loop) {
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bdrv_unref(bs);
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}
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}
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return waited;
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}
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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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bdrv_dec_in_flight(bs);
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bdrv_drained_begin(bs);
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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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{
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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 from
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* qemu_co_queue_run_restart(). */
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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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};
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bdrv_inc_in_flight(bs);
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aio_bh_schedule_oneshot(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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void bdrv_drained_begin(BlockDriverState *bs)
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{
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if (qemu_in_coroutine()) {
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bdrv_co_yield_to_drain(bs);
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return;
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}
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if (atomic_fetch_inc(&bs->quiesce_counter) == 0) {
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aio_disable_external(bdrv_get_aio_context(bs));
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bdrv_parent_drained_begin(bs);
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}
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bdrv_drain_recurse(bs);
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}
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void bdrv_drained_end(BlockDriverState *bs)
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{
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assert(bs->quiesce_counter > 0);
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if (atomic_fetch_dec(&bs->quiesce_counter) > 1) {
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return;
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}
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bdrv_parent_drained_end(bs);
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aio_enable_external(bdrv_get_aio_context(bs));
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}
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/*
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* Wait for pending requests to complete on a single BlockDriverState subtree,
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* and suspend block driver's internal I/O until next request arrives.
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*
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* Note that unlike bdrv_drain_all(), the caller must hold the BlockDriverState
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* AioContext.
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*
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* Only this BlockDriverState's AioContext is run, so in-flight requests must
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* not depend on events in other AioContexts. In that case, use
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* bdrv_drain_all() instead.
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*/
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void coroutine_fn bdrv_co_drain(BlockDriverState *bs)
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{
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assert(qemu_in_coroutine());
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bdrv_drained_begin(bs);
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bdrv_drained_end(bs);
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}
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void bdrv_drain(BlockDriverState *bs)
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{
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bdrv_drained_begin(bs);
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bdrv_drained_end(bs);
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}
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/*
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* Wait for pending requests to complete across all BlockDriverStates
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*
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* This function does not flush data to disk, use bdrv_flush_all() for that
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* after calling this function.
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*
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* This pauses all block jobs and disables external clients. It must
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* be paired with bdrv_drain_all_end().
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*
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* NOTE: no new block jobs or BlockDriverStates can be created between
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* the bdrv_drain_all_begin() and bdrv_drain_all_end() calls.
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*/
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void bdrv_drain_all_begin(void)
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{
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/* Always run first iteration so any pending completion BHs run */
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bool waited = true;
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BlockDriverState *bs;
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BdrvNextIterator it;
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GSList *aio_ctxs = NULL, *ctx;
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block_job_pause_all();
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for (bs = bdrv_first(&it); bs; bs = bdrv_next(&it)) {
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AioContext *aio_context = bdrv_get_aio_context(bs);
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aio_context_acquire(aio_context);
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bdrv_parent_drained_begin(bs);
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aio_disable_external(aio_context);
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aio_context_release(aio_context);
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if (!g_slist_find(aio_ctxs, aio_context)) {
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aio_ctxs = g_slist_prepend(aio_ctxs, aio_context);
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}
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}
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/* Note that completion of an asynchronous I/O operation can trigger any
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* number of other I/O operations on other devices---for example a
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* coroutine can submit an I/O request to another device in response to
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* request completion. Therefore we must keep looping until there was no
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* more activity rather than simply draining each device independently.
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*/
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while (waited) {
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waited = false;
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for (ctx = aio_ctxs; ctx != NULL; ctx = ctx->next) {
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AioContext *aio_context = ctx->data;
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aio_context_acquire(aio_context);
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for (bs = bdrv_first(&it); bs; bs = bdrv_next(&it)) {
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if (aio_context == bdrv_get_aio_context(bs)) {
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waited |= bdrv_drain_recurse(bs);
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}
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}
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aio_context_release(aio_context);
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}
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}
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g_slist_free(aio_ctxs);
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}
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void bdrv_drain_all_end(void)
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{
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BlockDriverState *bs;
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BdrvNextIterator it;
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for (bs = bdrv_first(&it); bs; bs = bdrv_next(&it)) {
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AioContext *aio_context = bdrv_get_aio_context(bs);
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aio_context_acquire(aio_context);
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aio_enable_external(aio_context);
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bdrv_parent_drained_end(bs);
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aio_context_release(aio_context);
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}
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block_job_resume_all();
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}
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void bdrv_drain_all(void)
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{
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bdrv_drain_all_begin();
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bdrv_drain_all_end();
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}
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|
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/**
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* Remove an active request from the tracked requests list
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*
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* This function should be called when a tracked request is completing.
|
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*/
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static void tracked_request_end(BdrvTrackedRequest *req)
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{
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if (req->serialising) {
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atomic_dec(&req->bs->serialising_in_flight);
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}
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qemu_co_mutex_lock(&req->bs->reqs_lock);
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QLIST_REMOVE(req, list);
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qemu_co_queue_restart_all(&req->wait_queue);
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qemu_co_mutex_unlock(&req->bs->reqs_lock);
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}
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/**
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* Add an active request to the tracked requests list
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*/
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static void tracked_request_begin(BdrvTrackedRequest *req,
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BlockDriverState *bs,
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int64_t offset,
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unsigned int bytes,
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enum BdrvTrackedRequestType type)
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{
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*req = (BdrvTrackedRequest){
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.bs = bs,
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.offset = offset,
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.bytes = bytes,
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.type = type,
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.co = qemu_coroutine_self(),
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.serialising = false,
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.overlap_offset = offset,
|
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.overlap_bytes = bytes,
|
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};
|
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|
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qemu_co_queue_init(&req->wait_queue);
|
|
|
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qemu_co_mutex_lock(&bs->reqs_lock);
|
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QLIST_INSERT_HEAD(&bs->tracked_requests, req, list);
|
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qemu_co_mutex_unlock(&bs->reqs_lock);
|
|
}
|
|
|
|
static void mark_request_serialising(BdrvTrackedRequest *req, uint64_t align)
|
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{
|
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int64_t overlap_offset = req->offset & ~(align - 1);
|
|
unsigned int overlap_bytes = ROUND_UP(req->offset + req->bytes, align)
|
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- overlap_offset;
|
|
|
|
if (!req->serialising) {
|
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atomic_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);
|
|
}
|
|
|
|
/**
|
|
* Round a region to cluster boundaries
|
|
*/
|
|
void bdrv_round_to_clusters(BlockDriverState *bs,
|
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int64_t offset, unsigned int bytes,
|
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int64_t *cluster_offset,
|
|
unsigned int *cluster_bytes)
|
|
{
|
|
BlockDriverInfo bdi;
|
|
|
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if (bdrv_get_info(bs, &bdi) < 0 || bdi.cluster_size == 0) {
|
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*cluster_offset = offset;
|
|
*cluster_bytes = bytes;
|
|
} else {
|
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int64_t c = bdi.cluster_size;
|
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*cluster_offset = QEMU_ALIGN_DOWN(offset, c);
|
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*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;
|
|
}
|
|
}
|
|
|
|
static bool tracked_request_overlaps(BdrvTrackedRequest *req,
|
|
int64_t offset, unsigned int 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;
|
|
}
|
|
|
|
void bdrv_inc_in_flight(BlockDriverState *bs)
|
|
{
|
|
atomic_inc(&bs->in_flight);
|
|
}
|
|
|
|
static void dummy_bh_cb(void *opaque)
|
|
{
|
|
}
|
|
|
|
void bdrv_wakeup(BlockDriverState *bs)
|
|
{
|
|
/* The barrier (or an atomic op) is in the caller. */
|
|
if (atomic_read(&bs->wakeup)) {
|
|
aio_bh_schedule_oneshot(qemu_get_aio_context(), dummy_bh_cb, NULL);
|
|
}
|
|
}
|
|
|
|
void bdrv_dec_in_flight(BlockDriverState *bs)
|
|
{
|
|
atomic_dec(&bs->in_flight);
|
|
bdrv_wakeup(bs);
|
|
}
|
|
|
|
static bool coroutine_fn wait_serialising_requests(BdrvTrackedRequest *self)
|
|
{
|
|
BlockDriverState *bs = self->bs;
|
|
BdrvTrackedRequest *req;
|
|
bool retry;
|
|
bool waited = false;
|
|
|
|
if (!atomic_read(&bs->serialising_in_flight)) {
|
|
return false;
|
|
}
|
|
|
|
do {
|
|
retry = false;
|
|
qemu_co_mutex_lock(&bs->reqs_lock);
|
|
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;
|
|
}
|
|
}
|
|
}
|
|
qemu_co_mutex_unlock(&bs->reqs_lock);
|
|
} while (retry);
|
|
|
|
return waited;
|
|
}
|
|
|
|
static int bdrv_check_byte_request(BlockDriverState *bs, int64_t offset,
|
|
size_t size)
|
|
{
|
|
if (size > BDRV_REQUEST_MAX_SECTORS << BDRV_SECTOR_BITS) {
|
|
return -EIO;
|
|
}
|
|
|
|
if (!bdrv_is_inserted(bs)) {
|
|
return -ENOMEDIUM;
|
|
}
|
|
|
|
if (offset < 0) {
|
|
return -EIO;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
typedef struct RwCo {
|
|
BdrvChild *child;
|
|
int64_t offset;
|
|
QEMUIOVector *qiov;
|
|
bool is_write;
|
|
int ret;
|
|
BdrvRequestFlags flags;
|
|
} RwCo;
|
|
|
|
static void coroutine_fn bdrv_rw_co_entry(void *opaque)
|
|
{
|
|
RwCo *rwco = opaque;
|
|
|
|
if (!rwco->is_write) {
|
|
rwco->ret = bdrv_co_preadv(rwco->child, rwco->offset,
|
|
rwco->qiov->size, rwco->qiov,
|
|
rwco->flags);
|
|
} else {
|
|
rwco->ret = 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)
|
|
{
|
|
Coroutine *co;
|
|
RwCo rwco = {
|
|
.child = child,
|
|
.offset = offset,
|
|
.qiov = qiov,
|
|
.is_write = is_write,
|
|
.ret = NOT_DONE,
|
|
.flags = flags,
|
|
};
|
|
|
|
if (qemu_in_coroutine()) {
|
|
/* Fast-path if already in coroutine context */
|
|
bdrv_rw_co_entry(&rwco);
|
|
} else {
|
|
co = qemu_coroutine_create(bdrv_rw_co_entry, &rwco);
|
|
bdrv_coroutine_enter(child->bs, co);
|
|
BDRV_POLL_WHILE(child->bs, rwco.ret == NOT_DONE);
|
|
}
|
|
return rwco.ret;
|
|
}
|
|
|
|
/*
|
|
* Process a synchronous request using coroutines
|
|
*/
|
|
static int bdrv_rw_co(BdrvChild *child, int64_t sector_num, uint8_t *buf,
|
|
int nb_sectors, bool is_write, BdrvRequestFlags flags)
|
|
{
|
|
QEMUIOVector qiov;
|
|
struct iovec iov = {
|
|
.iov_base = (void *)buf,
|
|
.iov_len = nb_sectors * BDRV_SECTOR_SIZE,
|
|
};
|
|
|
|
if (nb_sectors < 0 || nb_sectors > BDRV_REQUEST_MAX_SECTORS) {
|
|
return -EINVAL;
|
|
}
|
|
|
|
qemu_iovec_init_external(&qiov, &iov, 1);
|
|
return bdrv_prwv_co(child, sector_num << BDRV_SECTOR_BITS,
|
|
&qiov, is_write, flags);
|
|
}
|
|
|
|
/* return < 0 if error. See bdrv_write() for the return codes */
|
|
int bdrv_read(BdrvChild *child, int64_t sector_num,
|
|
uint8_t *buf, int nb_sectors)
|
|
{
|
|
return bdrv_rw_co(child, sector_num, buf, nb_sectors, false, 0);
|
|
}
|
|
|
|
/* Return < 0 if error. Important errors are:
|
|
-EIO generic I/O error (may happen for all errors)
|
|
-ENOMEDIUM No media inserted.
|
|
-EINVAL Invalid sector number or nb_sectors
|
|
-EACCES Trying to write a read-only device
|
|
*/
|
|
int bdrv_write(BdrvChild *child, int64_t sector_num,
|
|
const uint8_t *buf, int nb_sectors)
|
|
{
|
|
return bdrv_rw_co(child, sector_num, (uint8_t *)buf, nb_sectors, true, 0);
|
|
}
|
|
|
|
int bdrv_pwrite_zeroes(BdrvChild *child, int64_t offset,
|
|
int bytes, BdrvRequestFlags flags)
|
|
{
|
|
QEMUIOVector qiov;
|
|
struct iovec iov = {
|
|
.iov_base = NULL,
|
|
.iov_len = bytes,
|
|
};
|
|
|
|
qemu_iovec_init_external(&qiov, &iov, 1);
|
|
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_write().
|
|
*/
|
|
int bdrv_make_zero(BdrvChild *child, BdrvRequestFlags flags)
|
|
{
|
|
int64_t target_sectors, ret, nb_sectors, sector_num = 0;
|
|
BlockDriverState *bs = child->bs;
|
|
BlockDriverState *file;
|
|
int n;
|
|
|
|
target_sectors = bdrv_nb_sectors(bs);
|
|
if (target_sectors < 0) {
|
|
return target_sectors;
|
|
}
|
|
|
|
for (;;) {
|
|
nb_sectors = MIN(target_sectors - sector_num, BDRV_REQUEST_MAX_SECTORS);
|
|
if (nb_sectors <= 0) {
|
|
return 0;
|
|
}
|
|
ret = bdrv_get_block_status(bs, sector_num, nb_sectors, &n, &file);
|
|
if (ret < 0) {
|
|
error_report("error getting block status at sector %" PRId64 ": %s",
|
|
sector_num, strerror(-ret));
|
|
return ret;
|
|
}
|
|
if (ret & BDRV_BLOCK_ZERO) {
|
|
sector_num += n;
|
|
continue;
|
|
}
|
|
ret = bdrv_pwrite_zeroes(child, sector_num << BDRV_SECTOR_BITS,
|
|
n << BDRV_SECTOR_BITS, flags);
|
|
if (ret < 0) {
|
|
error_report("error writing zeroes at sector %" PRId64 ": %s",
|
|
sector_num, strerror(-ret));
|
|
return ret;
|
|
}
|
|
sector_num += n;
|
|
}
|
|
}
|
|
|
|
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;
|
|
}
|
|
|
|
int bdrv_pread(BdrvChild *child, int64_t offset, void *buf, int bytes)
|
|
{
|
|
QEMUIOVector qiov;
|
|
struct iovec iov = {
|
|
.iov_base = (void *)buf,
|
|
.iov_len = bytes,
|
|
};
|
|
|
|
if (bytes < 0) {
|
|
return -EINVAL;
|
|
}
|
|
|
|
qemu_iovec_init_external(&qiov, &iov, 1);
|
|
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;
|
|
}
|
|
|
|
int bdrv_pwrite(BdrvChild *child, int64_t offset, const void *buf, int bytes)
|
|
{
|
|
QEMUIOVector qiov;
|
|
struct iovec iov = {
|
|
.iov_base = (void *) buf,
|
|
.iov_len = bytes,
|
|
};
|
|
|
|
if (bytes < 0) {
|
|
return -EINVAL;
|
|
}
|
|
|
|
qemu_iovec_init_external(&qiov, &iov, 1);
|
|
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, int flags)
|
|
{
|
|
BlockDriver *drv = bs->drv;
|
|
int64_t sector_num;
|
|
unsigned int nb_sectors;
|
|
|
|
assert(!(flags & ~BDRV_REQ_MASK));
|
|
|
|
if (drv->bdrv_co_preadv) {
|
|
return drv->bdrv_co_preadv(bs, offset, bytes, qiov, flags);
|
|
}
|
|
|
|
sector_num = offset >> BDRV_SECTOR_BITS;
|
|
nb_sectors = bytes >> BDRV_SECTOR_BITS;
|
|
|
|
assert((offset & (BDRV_SECTOR_SIZE - 1)) == 0);
|
|
assert((bytes & (BDRV_SECTOR_SIZE - 1)) == 0);
|
|
assert((bytes >> BDRV_SECTOR_BITS) <= BDRV_REQUEST_MAX_SECTORS);
|
|
|
|
if (drv->bdrv_co_readv) {
|
|
return drv->bdrv_co_readv(bs, sector_num, nb_sectors, qiov);
|
|
} else {
|
|
BlockAIOCB *acb;
|
|
CoroutineIOCompletion co = {
|
|
.coroutine = qemu_coroutine_self(),
|
|
};
|
|
|
|
acb = bs->drv->bdrv_aio_readv(bs, sector_num, qiov, nb_sectors,
|
|
bdrv_co_io_em_complete, &co);
|
|
if (acb == NULL) {
|
|
return -EIO;
|
|
} else {
|
|
qemu_coroutine_yield();
|
|
return co.ret;
|
|
}
|
|
}
|
|
}
|
|
|
|
static int coroutine_fn bdrv_driver_pwritev(BlockDriverState *bs,
|
|
uint64_t offset, uint64_t bytes,
|
|
QEMUIOVector *qiov, int flags)
|
|
{
|
|
BlockDriver *drv = bs->drv;
|
|
int64_t sector_num;
|
|
unsigned int nb_sectors;
|
|
int ret;
|
|
|
|
assert(!(flags & ~BDRV_REQ_MASK));
|
|
|
|
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;
|
|
}
|
|
|
|
sector_num = offset >> BDRV_SECTOR_BITS;
|
|
nb_sectors = bytes >> BDRV_SECTOR_BITS;
|
|
|
|
assert((offset & (BDRV_SECTOR_SIZE - 1)) == 0);
|
|
assert((bytes & (BDRV_SECTOR_SIZE - 1)) == 0);
|
|
assert((bytes >> BDRV_SECTOR_BITS) <= BDRV_REQUEST_MAX_SECTORS);
|
|
|
|
if (drv->bdrv_co_writev_flags) {
|
|
ret = drv->bdrv_co_writev_flags(bs, sector_num, nb_sectors, qiov,
|
|
flags & bs->supported_write_flags);
|
|
flags &= ~bs->supported_write_flags;
|
|
} else if (drv->bdrv_co_writev) {
|
|
assert(!bs->supported_write_flags);
|
|
ret = drv->bdrv_co_writev(bs, sector_num, nb_sectors, qiov);
|
|
} else {
|
|
BlockAIOCB *acb;
|
|
CoroutineIOCompletion co = {
|
|
.coroutine = qemu_coroutine_self(),
|
|
};
|
|
|
|
acb = bs->drv->bdrv_aio_writev(bs, sector_num, qiov, nb_sectors,
|
|
bdrv_co_io_em_complete, &co);
|
|
if (acb == NULL) {
|
|
ret = -EIO;
|
|
} else {
|
|
qemu_coroutine_yield();
|
|
ret = co.ret;
|
|
}
|
|
}
|
|
|
|
emulate_flags:
|
|
if (ret == 0 && (flags & BDRV_REQ_FUA)) {
|
|
ret = bdrv_co_flush(bs);
|
|
}
|
|
|
|
return ret;
|
|
}
|
|
|
|
static int coroutine_fn
|
|
bdrv_driver_pwritev_compressed(BlockDriverState *bs, uint64_t offset,
|
|
uint64_t bytes, QEMUIOVector *qiov)
|
|
{
|
|
BlockDriver *drv = bs->drv;
|
|
|
|
if (!drv->bdrv_co_pwritev_compressed) {
|
|
return -ENOTSUP;
|
|
}
|
|
|
|
return drv->bdrv_co_pwritev_compressed(bs, offset, bytes, qiov);
|
|
}
|
|
|
|
static int coroutine_fn bdrv_co_do_copy_on_readv(BdrvChild *child,
|
|
int64_t offset, unsigned int bytes, QEMUIOVector *qiov)
|
|
{
|
|
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;
|
|
|
|
BlockDriver *drv = bs->drv;
|
|
struct iovec iov;
|
|
QEMUIOVector bounce_qiov;
|
|
int64_t cluster_offset;
|
|
unsigned int cluster_bytes;
|
|
size_t skip_bytes;
|
|
int ret;
|
|
|
|
/* 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 separat 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.
|
|
*/
|
|
bdrv_round_to_clusters(bs, offset, bytes, &cluster_offset, &cluster_bytes);
|
|
|
|
trace_bdrv_co_do_copy_on_readv(bs, offset, bytes,
|
|
cluster_offset, cluster_bytes);
|
|
|
|
iov.iov_len = cluster_bytes;
|
|
iov.iov_base = bounce_buffer = qemu_try_blockalign(bs, iov.iov_len);
|
|
if (bounce_buffer == NULL) {
|
|
ret = -ENOMEM;
|
|
goto err;
|
|
}
|
|
|
|
qemu_iovec_init_external(&bounce_qiov, &iov, 1);
|
|
|
|
ret = bdrv_driver_preadv(bs, cluster_offset, cluster_bytes,
|
|
&bounce_qiov, 0);
|
|
if (ret < 0) {
|
|
goto err;
|
|
}
|
|
|
|
if (drv->bdrv_co_pwrite_zeroes &&
|
|
buffer_is_zero(bounce_buffer, iov.iov_len)) {
|
|
/* 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, cluster_bytes, 0);
|
|
} 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, cluster_bytes,
|
|
&bounce_qiov, 0);
|
|
}
|
|
|
|
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;
|
|
}
|
|
|
|
skip_bytes = offset - cluster_offset;
|
|
qemu_iovec_from_buf(qiov, 0, bounce_buffer + skip_bytes, bytes);
|
|
|
|
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, 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(!qiov || bytes == qiov->size);
|
|
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_NO_SERIALISING | BDRV_REQ_COPY_ON_READ)));
|
|
|
|
/* 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. */
|
|
mark_request_serialising(req, bdrv_get_cluster_size(bs));
|
|
}
|
|
|
|
if (!(flags & BDRV_REQ_NO_SERIALISING)) {
|
|
wait_serialising_requests(req);
|
|
}
|
|
|
|
if (flags & BDRV_REQ_COPY_ON_READ) {
|
|
/* TODO: Simplify further once bdrv_is_allocated no longer
|
|
* requires sector alignment */
|
|
int64_t start = QEMU_ALIGN_DOWN(offset, BDRV_SECTOR_SIZE);
|
|
int64_t end = QEMU_ALIGN_UP(offset + bytes, BDRV_SECTOR_SIZE);
|
|
int64_t pnum;
|
|
|
|
ret = bdrv_is_allocated(bs, start, end - start, &pnum);
|
|
if (ret < 0) {
|
|
goto out;
|
|
}
|
|
|
|
if (!ret || pnum != end - start) {
|
|
ret = bdrv_co_do_copy_on_readv(child, offset, bytes, qiov);
|
|
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, 0);
|
|
goto out;
|
|
}
|
|
|
|
while (bytes_remaining) {
|
|
int num;
|
|
|
|
if (max_bytes) {
|
|
QEMUIOVector local_qiov;
|
|
|
|
num = MIN(bytes_remaining, MIN(max_bytes, max_transfer));
|
|
assert(num);
|
|
qemu_iovec_init(&local_qiov, qiov->niov);
|
|
qemu_iovec_concat(&local_qiov, qiov, bytes - bytes_remaining, num);
|
|
|
|
ret = bdrv_driver_preadv(bs, offset + bytes - bytes_remaining,
|
|
num, &local_qiov, 0);
|
|
max_bytes -= num;
|
|
qemu_iovec_destroy(&local_qiov);
|
|
} else {
|
|
num = bytes_remaining;
|
|
ret = qemu_iovec_memset(qiov, bytes - bytes_remaining, 0,
|
|
bytes_remaining);
|
|
}
|
|
if (ret < 0) {
|
|
goto out;
|
|
}
|
|
bytes_remaining -= num;
|
|
}
|
|
|
|
out:
|
|
return ret < 0 ? ret : 0;
|
|
}
|
|
|
|
/*
|
|
* Handle a read request in coroutine context
|
|
*/
|
|
int coroutine_fn bdrv_co_preadv(BdrvChild *child,
|
|
int64_t offset, unsigned int bytes, QEMUIOVector *qiov,
|
|
BdrvRequestFlags flags)
|
|
{
|
|
BlockDriverState *bs = child->bs;
|
|
BlockDriver *drv = bs->drv;
|
|
BdrvTrackedRequest req;
|
|
|
|
uint64_t align = bs->bl.request_alignment;
|
|
uint8_t *head_buf = NULL;
|
|
uint8_t *tail_buf = NULL;
|
|
QEMUIOVector local_qiov;
|
|
bool use_local_qiov = false;
|
|
int ret;
|
|
|
|
if (!drv) {
|
|
return -ENOMEDIUM;
|
|
}
|
|
|
|
ret = bdrv_check_byte_request(bs, offset, bytes);
|
|
if (ret < 0) {
|
|
return ret;
|
|
}
|
|
|
|
bdrv_inc_in_flight(bs);
|
|
|
|
/* Don't do copy-on-read if we read data before write operation */
|
|
if (atomic_read(&bs->copy_on_read) && !(flags & BDRV_REQ_NO_SERIALISING)) {
|
|
flags |= BDRV_REQ_COPY_ON_READ;
|
|
}
|
|
|
|
/* Align read if necessary by padding qiov */
|
|
if (offset & (align - 1)) {
|
|
head_buf = qemu_blockalign(bs, align);
|
|
qemu_iovec_init(&local_qiov, qiov->niov + 2);
|
|
qemu_iovec_add(&local_qiov, head_buf, offset & (align - 1));
|
|
qemu_iovec_concat(&local_qiov, qiov, 0, qiov->size);
|
|
use_local_qiov = true;
|
|
|
|
bytes += offset & (align - 1);
|
|
offset = offset & ~(align - 1);
|
|
}
|
|
|
|
if ((offset + bytes) & (align - 1)) {
|
|
if (!use_local_qiov) {
|
|
qemu_iovec_init(&local_qiov, qiov->niov + 1);
|
|
qemu_iovec_concat(&local_qiov, qiov, 0, qiov->size);
|
|
use_local_qiov = true;
|
|
}
|
|
tail_buf = qemu_blockalign(bs, align);
|
|
qemu_iovec_add(&local_qiov, tail_buf,
|
|
align - ((offset + bytes) & (align - 1)));
|
|
|
|
bytes = ROUND_UP(bytes, align);
|
|
}
|
|
|
|
tracked_request_begin(&req, bs, offset, bytes, BDRV_TRACKED_READ);
|
|
ret = bdrv_aligned_preadv(child, &req, offset, bytes, align,
|
|
use_local_qiov ? &local_qiov : qiov,
|
|
flags);
|
|
tracked_request_end(&req);
|
|
bdrv_dec_in_flight(bs);
|
|
|
|
if (use_local_qiov) {
|
|
qemu_iovec_destroy(&local_qiov);
|
|
qemu_vfree(head_buf);
|
|
qemu_vfree(tail_buf);
|
|
}
|
|
|
|
return ret;
|
|
}
|
|
|
|
static int coroutine_fn bdrv_co_do_readv(BdrvChild *child,
|
|
int64_t sector_num, int nb_sectors, QEMUIOVector *qiov,
|
|
BdrvRequestFlags flags)
|
|
{
|
|
if (nb_sectors < 0 || nb_sectors > BDRV_REQUEST_MAX_SECTORS) {
|
|
return -EINVAL;
|
|
}
|
|
|
|
return bdrv_co_preadv(child, sector_num << BDRV_SECTOR_BITS,
|
|
nb_sectors << BDRV_SECTOR_BITS, qiov, flags);
|
|
}
|
|
|
|
int coroutine_fn bdrv_co_readv(BdrvChild *child, int64_t sector_num,
|
|
int nb_sectors, QEMUIOVector *qiov)
|
|
{
|
|
trace_bdrv_co_readv(child->bs, sector_num, nb_sectors);
|
|
|
|
return bdrv_co_do_readv(child, sector_num, nb_sectors, qiov, 0);
|
|
}
|
|
|
|
/* Maximum buffer for write zeroes fallback, in bytes */
|
|
#define MAX_WRITE_ZEROES_BOUNCE_BUFFER (32768 << BDRV_SECTOR_BITS)
|
|
|
|
static int coroutine_fn bdrv_co_do_pwrite_zeroes(BlockDriverState *bs,
|
|
int64_t offset, int bytes, BdrvRequestFlags flags)
|
|
{
|
|
BlockDriver *drv = bs->drv;
|
|
QEMUIOVector qiov;
|
|
struct iovec iov = {0};
|
|
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_WRITE_ZEROES_BOUNCE_BUFFER);
|
|
|
|
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) {
|
|
/* 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);
|
|
iov.iov_len = num;
|
|
if (iov.iov_base == NULL) {
|
|
iov.iov_base = qemu_try_blockalign(bs, num);
|
|
if (iov.iov_base == NULL) {
|
|
ret = -ENOMEM;
|
|
goto fail;
|
|
}
|
|
memset(iov.iov_base, 0, num);
|
|
}
|
|
qemu_iovec_init_external(&qiov, &iov, 1);
|
|
|
|
ret = bdrv_driver_pwritev(bs, offset, num, &qiov, write_flags);
|
|
|
|
/* Keep bounce buffer around if it is big enough for all
|
|
* all future requests.
|
|
*/
|
|
if (num < max_transfer) {
|
|
qemu_vfree(iov.iov_base);
|
|
iov.iov_base = NULL;
|
|
}
|
|
}
|
|
|
|
offset += num;
|
|
bytes -= num;
|
|
}
|
|
|
|
fail:
|
|
if (ret == 0 && need_flush) {
|
|
ret = bdrv_co_flush(bs);
|
|
}
|
|
qemu_vfree(iov.iov_base);
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* 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, int flags)
|
|
{
|
|
BlockDriverState *bs = child->bs;
|
|
BlockDriver *drv = bs->drv;
|
|
bool waited;
|
|
int ret;
|
|
|
|
int64_t start_sector = offset >> BDRV_SECTOR_BITS;
|
|
int64_t end_sector = DIV_ROUND_UP(offset + bytes, BDRV_SECTOR_SIZE);
|
|
uint64_t bytes_remaining = bytes;
|
|
int max_transfer;
|
|
|
|
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 || bytes == qiov->size);
|
|
assert((bs->open_flags & BDRV_O_NO_IO) == 0);
|
|
assert(!(flags & ~BDRV_REQ_MASK));
|
|
max_transfer = QEMU_ALIGN_DOWN(MIN_NON_ZERO(bs->bl.max_transfer, INT_MAX),
|
|
align);
|
|
|
|
waited = wait_serialising_requests(req);
|
|
assert(!waited || !req->serialising);
|
|
assert(req->overlap_offset <= offset);
|
|
assert(offset + bytes <= req->overlap_offset + req->overlap_bytes);
|
|
assert(child->perm & BLK_PERM_WRITE);
|
|
assert(end_sector <= bs->total_sectors || child->perm & BLK_PERM_RESIZE);
|
|
|
|
ret = notifier_with_return_list_notify(&bs->before_write_notifiers, req);
|
|
|
|
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)) {
|
|
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);
|
|
} else if (bytes <= max_transfer) {
|
|
bdrv_debug_event(bs, BLKDBG_PWRITEV);
|
|
ret = bdrv_driver_pwritev(bs, offset, bytes, qiov, flags);
|
|
} else {
|
|
bdrv_debug_event(bs, BLKDBG_PWRITEV);
|
|
while (bytes_remaining) {
|
|
int num = MIN(bytes_remaining, max_transfer);
|
|
QEMUIOVector local_qiov;
|
|
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;
|
|
}
|
|
qemu_iovec_init(&local_qiov, qiov->niov);
|
|
qemu_iovec_concat(&local_qiov, qiov, bytes - bytes_remaining, num);
|
|
|
|
ret = bdrv_driver_pwritev(bs, offset + bytes - bytes_remaining,
|
|
num, &local_qiov, local_flags);
|
|
qemu_iovec_destroy(&local_qiov);
|
|
if (ret < 0) {
|
|
break;
|
|
}
|
|
bytes_remaining -= num;
|
|
}
|
|
}
|
|
bdrv_debug_event(bs, BLKDBG_PWRITEV_DONE);
|
|
|
|
atomic_inc(&bs->write_gen);
|
|
bdrv_set_dirty(bs, start_sector, end_sector - start_sector);
|
|
|
|
stat64_max(&bs->wr_highest_offset, offset + bytes);
|
|
|
|
if (ret >= 0) {
|
|
bs->total_sectors = MAX(bs->total_sectors, end_sector);
|
|
ret = 0;
|
|
}
|
|
|
|
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;
|
|
uint8_t *buf = NULL;
|
|
QEMUIOVector local_qiov;
|
|
struct iovec iov;
|
|
uint64_t align = bs->bl.request_alignment;
|
|
unsigned int head_padding_bytes, tail_padding_bytes;
|
|
int ret = 0;
|
|
|
|
head_padding_bytes = offset & (align - 1);
|
|
tail_padding_bytes = (align - (offset + bytes)) & (align - 1);
|
|
|
|
|
|
assert(flags & BDRV_REQ_ZERO_WRITE);
|
|
if (head_padding_bytes || tail_padding_bytes) {
|
|
buf = qemu_blockalign(bs, align);
|
|
iov = (struct iovec) {
|
|
.iov_base = buf,
|
|
.iov_len = align,
|
|
};
|
|
qemu_iovec_init_external(&local_qiov, &iov, 1);
|
|
}
|
|
if (head_padding_bytes) {
|
|
uint64_t zero_bytes = MIN(bytes, align - head_padding_bytes);
|
|
|
|
/* RMW the unaligned part before head. */
|
|
mark_request_serialising(req, align);
|
|
wait_serialising_requests(req);
|
|
bdrv_debug_event(bs, BLKDBG_PWRITEV_RMW_HEAD);
|
|
ret = bdrv_aligned_preadv(child, req, offset & ~(align - 1), align,
|
|
align, &local_qiov, 0);
|
|
if (ret < 0) {
|
|
goto fail;
|
|
}
|
|
bdrv_debug_event(bs, BLKDBG_PWRITEV_RMW_AFTER_HEAD);
|
|
|
|
memset(buf + head_padding_bytes, 0, zero_bytes);
|
|
ret = bdrv_aligned_pwritev(child, req, offset & ~(align - 1), align,
|
|
align, &local_qiov,
|
|
flags & ~BDRV_REQ_ZERO_WRITE);
|
|
if (ret < 0) {
|
|
goto fail;
|
|
}
|
|
offset += zero_bytes;
|
|
bytes -= zero_bytes;
|
|
}
|
|
|
|
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, flags);
|
|
if (ret < 0) {
|
|
goto fail;
|
|
}
|
|
bytes -= aligned_bytes;
|
|
offset += aligned_bytes;
|
|
}
|
|
|
|
assert(!bytes || (offset & (align - 1)) == 0);
|
|
if (bytes) {
|
|
assert(align == tail_padding_bytes + bytes);
|
|
/* RMW the unaligned part after tail. */
|
|
mark_request_serialising(req, align);
|
|
wait_serialising_requests(req);
|
|
bdrv_debug_event(bs, BLKDBG_PWRITEV_RMW_TAIL);
|
|
ret = bdrv_aligned_preadv(child, req, offset, align,
|
|
align, &local_qiov, 0);
|
|
if (ret < 0) {
|
|
goto fail;
|
|
}
|
|
bdrv_debug_event(bs, BLKDBG_PWRITEV_RMW_AFTER_TAIL);
|
|
|
|
memset(buf, 0, bytes);
|
|
ret = bdrv_aligned_pwritev(child, req, offset, align, align,
|
|
&local_qiov, flags & ~BDRV_REQ_ZERO_WRITE);
|
|
}
|
|
fail:
|
|
qemu_vfree(buf);
|
|
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)
|
|
{
|
|
BlockDriverState *bs = child->bs;
|
|
BdrvTrackedRequest req;
|
|
uint64_t align = bs->bl.request_alignment;
|
|
uint8_t *head_buf = NULL;
|
|
uint8_t *tail_buf = NULL;
|
|
QEMUIOVector local_qiov;
|
|
bool use_local_qiov = false;
|
|
int ret;
|
|
|
|
if (!bs->drv) {
|
|
return -ENOMEDIUM;
|
|
}
|
|
if (bs->read_only) {
|
|
return -EPERM;
|
|
}
|
|
assert(!(bs->open_flags & BDRV_O_INACTIVE));
|
|
|
|
ret = bdrv_check_byte_request(bs, offset, bytes);
|
|
if (ret < 0) {
|
|
return ret;
|
|
}
|
|
|
|
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 (!qiov) {
|
|
ret = bdrv_co_do_zero_pwritev(child, offset, bytes, flags, &req);
|
|
goto out;
|
|
}
|
|
|
|
if (offset & (align - 1)) {
|
|
QEMUIOVector head_qiov;
|
|
struct iovec head_iov;
|
|
|
|
mark_request_serialising(&req, align);
|
|
wait_serialising_requests(&req);
|
|
|
|
head_buf = qemu_blockalign(bs, align);
|
|
head_iov = (struct iovec) {
|
|
.iov_base = head_buf,
|
|
.iov_len = align,
|
|
};
|
|
qemu_iovec_init_external(&head_qiov, &head_iov, 1);
|
|
|
|
bdrv_debug_event(bs, BLKDBG_PWRITEV_RMW_HEAD);
|
|
ret = bdrv_aligned_preadv(child, &req, offset & ~(align - 1), align,
|
|
align, &head_qiov, 0);
|
|
if (ret < 0) {
|
|
goto fail;
|
|
}
|
|
bdrv_debug_event(bs, BLKDBG_PWRITEV_RMW_AFTER_HEAD);
|
|
|
|
qemu_iovec_init(&local_qiov, qiov->niov + 2);
|
|
qemu_iovec_add(&local_qiov, head_buf, offset & (align - 1));
|
|
qemu_iovec_concat(&local_qiov, qiov, 0, qiov->size);
|
|
use_local_qiov = true;
|
|
|
|
bytes += offset & (align - 1);
|
|
offset = offset & ~(align - 1);
|
|
|
|
/* We have read the tail already if the request is smaller
|
|
* than one aligned block.
|
|
*/
|
|
if (bytes < align) {
|
|
qemu_iovec_add(&local_qiov, head_buf + bytes, align - bytes);
|
|
bytes = align;
|
|
}
|
|
}
|
|
|
|
if ((offset + bytes) & (align - 1)) {
|
|
QEMUIOVector tail_qiov;
|
|
struct iovec tail_iov;
|
|
size_t tail_bytes;
|
|
bool waited;
|
|
|
|
mark_request_serialising(&req, align);
|
|
waited = wait_serialising_requests(&req);
|
|
assert(!waited || !use_local_qiov);
|
|
|
|
tail_buf = qemu_blockalign(bs, align);
|
|
tail_iov = (struct iovec) {
|
|
.iov_base = tail_buf,
|
|
.iov_len = align,
|
|
};
|
|
qemu_iovec_init_external(&tail_qiov, &tail_iov, 1);
|
|
|
|
bdrv_debug_event(bs, BLKDBG_PWRITEV_RMW_TAIL);
|
|
ret = bdrv_aligned_preadv(child, &req, (offset + bytes) & ~(align - 1),
|
|
align, align, &tail_qiov, 0);
|
|
if (ret < 0) {
|
|
goto fail;
|
|
}
|
|
bdrv_debug_event(bs, BLKDBG_PWRITEV_RMW_AFTER_TAIL);
|
|
|
|
if (!use_local_qiov) {
|
|
qemu_iovec_init(&local_qiov, qiov->niov + 1);
|
|
qemu_iovec_concat(&local_qiov, qiov, 0, qiov->size);
|
|
use_local_qiov = true;
|
|
}
|
|
|
|
tail_bytes = (offset + bytes) & (align - 1);
|
|
qemu_iovec_add(&local_qiov, tail_buf + tail_bytes, align - tail_bytes);
|
|
|
|
bytes = ROUND_UP(bytes, align);
|
|
}
|
|
|
|
ret = bdrv_aligned_pwritev(child, &req, offset, bytes, align,
|
|
use_local_qiov ? &local_qiov : qiov,
|
|
flags);
|
|
|
|
fail:
|
|
|
|
if (use_local_qiov) {
|
|
qemu_iovec_destroy(&local_qiov);
|
|
}
|
|
qemu_vfree(head_buf);
|
|
qemu_vfree(tail_buf);
|
|
out:
|
|
tracked_request_end(&req);
|
|
bdrv_dec_in_flight(bs);
|
|
return ret;
|
|
}
|
|
|
|
static int coroutine_fn bdrv_co_do_writev(BdrvChild *child,
|
|
int64_t sector_num, int nb_sectors, QEMUIOVector *qiov,
|
|
BdrvRequestFlags flags)
|
|
{
|
|
if (nb_sectors < 0 || nb_sectors > BDRV_REQUEST_MAX_SECTORS) {
|
|
return -EINVAL;
|
|
}
|
|
|
|
return bdrv_co_pwritev(child, sector_num << BDRV_SECTOR_BITS,
|
|
nb_sectors << BDRV_SECTOR_BITS, qiov, flags);
|
|
}
|
|
|
|
int coroutine_fn bdrv_co_writev(BdrvChild *child, int64_t sector_num,
|
|
int nb_sectors, QEMUIOVector *qiov)
|
|
{
|
|
trace_bdrv_co_writev(child->bs, sector_num, nb_sectors);
|
|
|
|
return bdrv_co_do_writev(child, sector_num, nb_sectors, qiov, 0);
|
|
}
|
|
|
|
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;
|
|
|
|
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 BdrvCoGetBlockStatusData {
|
|
BlockDriverState *bs;
|
|
BlockDriverState *base;
|
|
BlockDriverState **file;
|
|
int64_t sector_num;
|
|
int nb_sectors;
|
|
int *pnum;
|
|
int64_t ret;
|
|
bool done;
|
|
} BdrvCoGetBlockStatusData;
|
|
|
|
/*
|
|
* 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 'sector_num' is beyond the end of the disk image the return value is
|
|
* BDRV_BLOCK_EOF and 'pnum' is set to 0.
|
|
*
|
|
* 'pnum' is set to the number of sectors (including and immediately following
|
|
* the specified sector) that are known to be in the same
|
|
* allocated/unallocated state.
|
|
*
|
|
* 'nb_sectors' is the max value 'pnum' should be set to. If nb_sectors 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.
|
|
*
|
|
* If returned value is positive and BDRV_BLOCK_OFFSET_VALID bit is set, 'file'
|
|
* points to the BDS which the sector range is allocated in.
|
|
*/
|
|
static int64_t coroutine_fn bdrv_co_get_block_status(BlockDriverState *bs,
|
|
int64_t sector_num,
|
|
int nb_sectors, int *pnum,
|
|
BlockDriverState **file)
|
|
{
|
|
int64_t total_sectors;
|
|
int64_t n;
|
|
int64_t ret, ret2;
|
|
|
|
*file = NULL;
|
|
total_sectors = bdrv_nb_sectors(bs);
|
|
if (total_sectors < 0) {
|
|
return total_sectors;
|
|
}
|
|
|
|
if (sector_num >= total_sectors) {
|
|
*pnum = 0;
|
|
return BDRV_BLOCK_EOF;
|
|
}
|
|
|
|
n = total_sectors - sector_num;
|
|
if (n < nb_sectors) {
|
|
nb_sectors = n;
|
|
}
|
|
|
|
if (!bs->drv->bdrv_co_get_block_status) {
|
|
*pnum = nb_sectors;
|
|
ret = BDRV_BLOCK_DATA | BDRV_BLOCK_ALLOCATED;
|
|
if (sector_num + nb_sectors == total_sectors) {
|
|
ret |= BDRV_BLOCK_EOF;
|
|
}
|
|
if (bs->drv->protocol_name) {
|
|
ret |= BDRV_BLOCK_OFFSET_VALID | (sector_num * BDRV_SECTOR_SIZE);
|
|
*file = bs;
|
|
}
|
|
return ret;
|
|
}
|
|
|
|
bdrv_inc_in_flight(bs);
|
|
ret = bs->drv->bdrv_co_get_block_status(bs, sector_num, nb_sectors, pnum,
|
|
file);
|
|
if (ret < 0) {
|
|
*pnum = 0;
|
|
goto out;
|
|
}
|
|
|
|
if (ret & BDRV_BLOCK_RAW) {
|
|
assert(ret & BDRV_BLOCK_OFFSET_VALID && *file);
|
|
ret = bdrv_co_get_block_status(*file, ret >> BDRV_SECTOR_BITS,
|
|
*pnum, pnum, file);
|
|
goto out;
|
|
}
|
|
|
|
if (ret & (BDRV_BLOCK_DATA | BDRV_BLOCK_ZERO)) {
|
|
ret |= BDRV_BLOCK_ALLOCATED;
|
|
} else {
|
|
if (bdrv_unallocated_blocks_are_zero(bs)) {
|
|
ret |= BDRV_BLOCK_ZERO;
|
|
} else if (bs->backing) {
|
|
BlockDriverState *bs2 = bs->backing->bs;
|
|
int64_t nb_sectors2 = bdrv_nb_sectors(bs2);
|
|
if (nb_sectors2 >= 0 && sector_num >= nb_sectors2) {
|
|
ret |= BDRV_BLOCK_ZERO;
|
|
}
|
|
}
|
|
}
|
|
|
|
if (*file && *file != bs &&
|
|
(ret & BDRV_BLOCK_DATA) && !(ret & BDRV_BLOCK_ZERO) &&
|
|
(ret & BDRV_BLOCK_OFFSET_VALID)) {
|
|
BlockDriverState *file2;
|
|
int file_pnum;
|
|
|
|
ret2 = bdrv_co_get_block_status(*file, ret >> BDRV_SECTOR_BITS,
|
|
*pnum, &file_pnum, &file2);
|
|
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 && sector_num + *pnum == total_sectors) {
|
|
ret |= BDRV_BLOCK_EOF;
|
|
}
|
|
return ret;
|
|
}
|
|
|
|
static int64_t coroutine_fn bdrv_co_get_block_status_above(BlockDriverState *bs,
|
|
BlockDriverState *base,
|
|
int64_t sector_num,
|
|
int nb_sectors,
|
|
int *pnum,
|
|
BlockDriverState **file)
|
|
{
|
|
BlockDriverState *p;
|
|
int64_t ret = 0;
|
|
bool first = true;
|
|
|
|
assert(bs != base);
|
|
for (p = bs; p != base; p = backing_bs(p)) {
|
|
ret = bdrv_co_get_block_status(p, sector_num, nb_sectors, pnum, 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 = nb_sectors;
|
|
}
|
|
if (ret & (BDRV_BLOCK_ZERO | BDRV_BLOCK_DATA)) {
|
|
break;
|
|
}
|
|
/* [sector_num, pnum] unallocated on this layer, which could be only
|
|
* the first part of [sector_num, nb_sectors]. */
|
|
nb_sectors = MIN(nb_sectors, *pnum);
|
|
first = false;
|
|
}
|
|
return ret;
|
|
}
|
|
|
|
/* Coroutine wrapper for bdrv_get_block_status_above() */
|
|
static void coroutine_fn bdrv_get_block_status_above_co_entry(void *opaque)
|
|
{
|
|
BdrvCoGetBlockStatusData *data = opaque;
|
|
|
|
data->ret = bdrv_co_get_block_status_above(data->bs, data->base,
|
|
data->sector_num,
|
|
data->nb_sectors,
|
|
data->pnum,
|
|
data->file);
|
|
data->done = true;
|
|
}
|
|
|
|
/*
|
|
* Synchronous wrapper around bdrv_co_get_block_status_above().
|
|
*
|
|
* See bdrv_co_get_block_status_above() for details.
|
|
*/
|
|
int64_t bdrv_get_block_status_above(BlockDriverState *bs,
|
|
BlockDriverState *base,
|
|
int64_t sector_num,
|
|
int nb_sectors, int *pnum,
|
|
BlockDriverState **file)
|
|
{
|
|
Coroutine *co;
|
|
BdrvCoGetBlockStatusData data = {
|
|
.bs = bs,
|
|
.base = base,
|
|
.file = file,
|
|
.sector_num = sector_num,
|
|
.nb_sectors = nb_sectors,
|
|
.pnum = pnum,
|
|
.done = false,
|
|
};
|
|
|
|
if (qemu_in_coroutine()) {
|
|
/* Fast-path if already in coroutine context */
|
|
bdrv_get_block_status_above_co_entry(&data);
|
|
} else {
|
|
co = qemu_coroutine_create(bdrv_get_block_status_above_co_entry,
|
|
&data);
|
|
bdrv_coroutine_enter(bs, co);
|
|
BDRV_POLL_WHILE(bs, !data.done);
|
|
}
|
|
return data.ret;
|
|
}
|
|
|
|
int64_t bdrv_get_block_status(BlockDriverState *bs,
|
|
int64_t sector_num,
|
|
int nb_sectors, int *pnum,
|
|
BlockDriverState **file)
|
|
{
|
|
return bdrv_get_block_status_above(bs, backing_bs(bs),
|
|
sector_num, nb_sectors, pnum, file);
|
|
}
|
|
|
|
int coroutine_fn bdrv_is_allocated(BlockDriverState *bs, int64_t offset,
|
|
int64_t bytes, int64_t *pnum)
|
|
{
|
|
BlockDriverState *file;
|
|
int64_t sector_num = offset >> BDRV_SECTOR_BITS;
|
|
int nb_sectors = bytes >> BDRV_SECTOR_BITS;
|
|
int64_t ret;
|
|
int psectors;
|
|
|
|
assert(QEMU_IS_ALIGNED(offset, BDRV_SECTOR_SIZE));
|
|
assert(QEMU_IS_ALIGNED(bytes, BDRV_SECTOR_SIZE) && bytes < INT_MAX);
|
|
ret = bdrv_get_block_status(bs, sector_num, nb_sectors, &psectors,
|
|
&file);
|
|
if (ret < 0) {
|
|
return ret;
|
|
}
|
|
if (pnum) {
|
|
*pnum = psectors * BDRV_SECTOR_SIZE;
|
|
}
|
|
return !!(ret & BDRV_BLOCK_ALLOCATED);
|
|
}
|
|
|
|
/*
|
|
* Given an image chain: ... -> [BASE] -> [INTER1] -> [INTER2] -> [TOP]
|
|
*
|
|
* Return true if (a prefix of) the given range is allocated in any image
|
|
* between BASE and TOP (inclusive). BASE can be NULL to check if the given
|
|
* offset is allocated in any image of the chain. Return false 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,
|
|
int64_t offset, int64_t bytes, int64_t *pnum)
|
|
{
|
|
BlockDriverState *intermediate;
|
|
int ret;
|
|
int64_t n = bytes;
|
|
|
|
intermediate = top;
|
|
while (intermediate && intermediate != base) {
|
|
int64_t pnum_inter;
|
|
int64_t size_inter;
|
|
|
|
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;
|
|
}
|
|
|
|
intermediate = backing_bs(intermediate);
|
|
}
|
|
|
|
*pnum = n;
|
|
return 0;
|
|
}
|
|
|
|
typedef struct BdrvVmstateCo {
|
|
BlockDriverState *bs;
|
|
QEMUIOVector *qiov;
|
|
int64_t pos;
|
|
bool is_read;
|
|
int ret;
|
|
} BdrvVmstateCo;
|
|
|
|
static int coroutine_fn
|
|
bdrv_co_rw_vmstate(BlockDriverState *bs, QEMUIOVector *qiov, int64_t pos,
|
|
bool is_read)
|
|
{
|
|
BlockDriver *drv = bs->drv;
|
|
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 (bs->file) {
|
|
ret = bdrv_co_rw_vmstate(bs->file->bs, qiov, pos, is_read);
|
|
}
|
|
|
|
bdrv_dec_in_flight(bs);
|
|
return ret;
|
|
}
|
|
|
|
static void coroutine_fn bdrv_co_rw_vmstate_entry(void *opaque)
|
|
{
|
|
BdrvVmstateCo *co = opaque;
|
|
co->ret = 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)
|
|
{
|
|
if (qemu_in_coroutine()) {
|
|
return bdrv_co_rw_vmstate(bs, qiov, pos, is_read);
|
|
} else {
|
|
BdrvVmstateCo data = {
|
|
.bs = bs,
|
|
.qiov = qiov,
|
|
.pos = pos,
|
|
.is_read = is_read,
|
|
.ret = -EINPROGRESS,
|
|
};
|
|
Coroutine *co = qemu_coroutine_create(bdrv_co_rw_vmstate_entry, &data);
|
|
|
|
bdrv_coroutine_enter(bs, co);
|
|
BDRV_POLL_WHILE(bs, data.ret == -EINPROGRESS);
|
|
return data.ret;
|
|
}
|
|
}
|
|
|
|
int bdrv_save_vmstate(BlockDriverState *bs, const uint8_t *buf,
|
|
int64_t pos, int size)
|
|
{
|
|
QEMUIOVector qiov;
|
|
struct iovec iov = {
|
|
.iov_base = (void *) buf,
|
|
.iov_len = size,
|
|
};
|
|
int ret;
|
|
|
|
qemu_iovec_init_external(&qiov, &iov, 1);
|
|
|
|
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;
|
|
struct iovec iov = {
|
|
.iov_base = buf,
|
|
.iov_len = size,
|
|
};
|
|
int ret;
|
|
|
|
qemu_iovec_init_external(&qiov, &iov, 1);
|
|
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 */
|
|
|
|
typedef struct FlushCo {
|
|
BlockDriverState *bs;
|
|
int ret;
|
|
} FlushCo;
|
|
|
|
|
|
static void coroutine_fn bdrv_flush_co_entry(void *opaque)
|
|
{
|
|
FlushCo *rwco = opaque;
|
|
|
|
rwco->ret = bdrv_co_flush(rwco->bs);
|
|
}
|
|
|
|
int coroutine_fn bdrv_co_flush(BlockDriverState *bs)
|
|
{
|
|
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 = atomic_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(bs->file, 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_parent;
|
|
}
|
|
|
|
/* Check if we really need to flush anything */
|
|
if (bs->flushed_gen == current_gen) {
|
|
goto flush_parent;
|
|
}
|
|
|
|
BLKDBG_EVENT(bs->file, BLKDBG_FLUSH_TO_DISK);
|
|
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_parent:
|
|
ret = bs->file ? bdrv_co_flush(bs->file->bs) : 0;
|
|
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)
|
|
{
|
|
Coroutine *co;
|
|
FlushCo flush_co = {
|
|
.bs = bs,
|
|
.ret = NOT_DONE,
|
|
};
|
|
|
|
if (qemu_in_coroutine()) {
|
|
/* Fast-path if already in coroutine context */
|
|
bdrv_flush_co_entry(&flush_co);
|
|
} else {
|
|
co = qemu_coroutine_create(bdrv_flush_co_entry, &flush_co);
|
|
bdrv_coroutine_enter(bs, co);
|
|
BDRV_POLL_WHILE(bs, flush_co.ret == NOT_DONE);
|
|
}
|
|
|
|
return flush_co.ret;
|
|
}
|
|
|
|
typedef struct DiscardCo {
|
|
BlockDriverState *bs;
|
|
int64_t offset;
|
|
int bytes;
|
|
int ret;
|
|
} DiscardCo;
|
|
static void coroutine_fn bdrv_pdiscard_co_entry(void *opaque)
|
|
{
|
|
DiscardCo *rwco = opaque;
|
|
|
|
rwco->ret = bdrv_co_pdiscard(rwco->bs, rwco->offset, rwco->bytes);
|
|
}
|
|
|
|
int coroutine_fn bdrv_co_pdiscard(BlockDriverState *bs, int64_t offset,
|
|
int bytes)
|
|
{
|
|
BdrvTrackedRequest req;
|
|
int max_pdiscard, ret;
|
|
int head, tail, align;
|
|
|
|
if (!bs->drv) {
|
|
return -ENOMEDIUM;
|
|
}
|
|
|
|
if (bdrv_has_readonly_bitmaps(bs)) {
|
|
return -EPERM;
|
|
}
|
|
|
|
ret = bdrv_check_byte_request(bs, offset, bytes);
|
|
if (ret < 0) {
|
|
return ret;
|
|
} else if (bs->read_only) {
|
|
return -EPERM;
|
|
}
|
|
assert(!(bs->open_flags & BDRV_O_INACTIVE));
|
|
|
|
/* 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 = notifier_with_return_list_notify(&bs->before_write_notifiers, &req);
|
|
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) {
|
|
int 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->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:
|
|
atomic_inc(&bs->write_gen);
|
|
bdrv_set_dirty(bs, req.offset >> BDRV_SECTOR_BITS,
|
|
req.bytes >> BDRV_SECTOR_BITS);
|
|
tracked_request_end(&req);
|
|
bdrv_dec_in_flight(bs);
|
|
return ret;
|
|
}
|
|
|
|
int bdrv_pdiscard(BlockDriverState *bs, int64_t offset, int bytes)
|
|
{
|
|
Coroutine *co;
|
|
DiscardCo rwco = {
|
|
.bs = bs,
|
|
.offset = offset,
|
|
.bytes = bytes,
|
|
.ret = NOT_DONE,
|
|
};
|
|
|
|
if (qemu_in_coroutine()) {
|
|
/* Fast-path if already in coroutine context */
|
|
bdrv_pdiscard_co_entry(&rwco);
|
|
} else {
|
|
co = qemu_coroutine_create(bdrv_pdiscard_co_entry, &rwco);
|
|
bdrv_coroutine_enter(bs, co);
|
|
BDRV_POLL_WHILE(bs, rwco.ret == NOT_DONE);
|
|
}
|
|
|
|
return rwco.ret;
|
|
}
|
|
|
|
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 (atomic_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 (atomic_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);
|
|
}
|
|
}
|