--- /dev/null
+/*
+ * Block layer I/O functions
+ *
+ * Copyright (c) 2003 Fabrice Bellard
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#include "trace.h"
+#include "block/blockjob.h"
+#include "block/block_int.h"
+#include "block/throttle-groups.h"
+#include "qemu/error-report.h"
+
+#define NOT_DONE 0x7fffffff /* used while emulated sync operation in progress */
+
+static BlockAIOCB *bdrv_aio_readv_em(BlockDriverState *bs,
+ int64_t sector_num, QEMUIOVector *qiov, int nb_sectors,
+ BlockCompletionFunc *cb, void *opaque);
+static BlockAIOCB *bdrv_aio_writev_em(BlockDriverState *bs,
+ int64_t sector_num, QEMUIOVector *qiov, int nb_sectors,
+ BlockCompletionFunc *cb, void *opaque);
+static int coroutine_fn bdrv_co_readv_em(BlockDriverState *bs,
+ int64_t sector_num, int nb_sectors,
+ QEMUIOVector *iov);
+static int coroutine_fn bdrv_co_writev_em(BlockDriverState *bs,
+ int64_t sector_num, int nb_sectors,
+ QEMUIOVector *iov);
+static int coroutine_fn bdrv_co_do_preadv(BlockDriverState *bs,
+ int64_t offset, unsigned int bytes, QEMUIOVector *qiov,
+ BdrvRequestFlags flags);
+static int coroutine_fn bdrv_co_do_pwritev(BlockDriverState *bs,
+ int64_t offset, unsigned int bytes, QEMUIOVector *qiov,
+ BdrvRequestFlags flags);
+static BlockAIOCB *bdrv_co_aio_rw_vector(BlockDriverState *bs,
+ int64_t sector_num,
+ QEMUIOVector *qiov,
+ int nb_sectors,
+ BdrvRequestFlags flags,
+ BlockCompletionFunc *cb,
+ void *opaque,
+ bool is_write);
+static void coroutine_fn bdrv_co_do_rw(void *opaque);
+static int coroutine_fn bdrv_co_do_write_zeroes(BlockDriverState *bs,
+ int64_t sector_num, int nb_sectors, BdrvRequestFlags flags);
+
+/* throttling disk I/O limits */
+void bdrv_set_io_limits(BlockDriverState *bs,
+ ThrottleConfig *cfg)
+{
+ int i;
+
+ throttle_group_config(bs, cfg);
+
+ for (i = 0; i < 2; i++) {
+ qemu_co_enter_next(&bs->throttled_reqs[i]);
+ }
+}
+
+/* this function drain all the throttled IOs */
+static bool bdrv_start_throttled_reqs(BlockDriverState *bs)
+{
+ bool drained = false;
+ bool enabled = bs->io_limits_enabled;
+ int i;
+
+ bs->io_limits_enabled = false;
+
+ for (i = 0; i < 2; i++) {
+ while (qemu_co_enter_next(&bs->throttled_reqs[i])) {
+ drained = true;
+ }
+ }
+
+ bs->io_limits_enabled = enabled;
+
+ return drained;
+}
+
+void bdrv_io_limits_disable(BlockDriverState *bs)
+{
+ bs->io_limits_enabled = false;
+ bdrv_start_throttled_reqs(bs);
+ throttle_group_unregister_bs(bs);
+}
+
+/* should be called before bdrv_set_io_limits if a limit is set */
+void bdrv_io_limits_enable(BlockDriverState *bs, const char *group)
+{
+ assert(!bs->io_limits_enabled);
+ throttle_group_register_bs(bs, group);
+ bs->io_limits_enabled = true;
+}
+
+void bdrv_io_limits_update_group(BlockDriverState *bs, const char *group)
+{
+ /* this bs is not part of any group */
+ if (!bs->throttle_state) {
+ return;
+ }
+
+ /* this bs is a part of the same group than the one we want */
+ if (!g_strcmp0(throttle_group_get_name(bs), group)) {
+ return;
+ }
+
+ /* need to change the group this bs belong to */
+ bdrv_io_limits_disable(bs);
+ bdrv_io_limits_enable(bs, group);
+}
+
+void bdrv_setup_io_funcs(BlockDriver *bdrv)
+{
+ /* Block drivers without coroutine functions need emulation */
+ if (!bdrv->bdrv_co_readv) {
+ bdrv->bdrv_co_readv = bdrv_co_readv_em;
+ bdrv->bdrv_co_writev = bdrv_co_writev_em;
+
+ /* bdrv_co_readv_em()/brdv_co_writev_em() work in terms of aio, so if
+ * the block driver lacks aio we need to emulate that too.
+ */
+ if (!bdrv->bdrv_aio_readv) {
+ /* add AIO emulation layer */
+ bdrv->bdrv_aio_readv = bdrv_aio_readv_em;
+ bdrv->bdrv_aio_writev = bdrv_aio_writev_em;
+ }
+ }
+}
+
+void bdrv_refresh_limits(BlockDriverState *bs, Error **errp)
+{
+ BlockDriver *drv = bs->drv;
+ Error *local_err = NULL;
+
+ memset(&bs->bl, 0, sizeof(bs->bl));
+
+ if (!drv) {
+ return;
+ }
+
+ /* Take some limits from the children as a default */
+ if (bs->file) {
+ bdrv_refresh_limits(bs->file, &local_err);
+ if (local_err) {
+ error_propagate(errp, local_err);
+ return;
+ }
+ bs->bl.opt_transfer_length = bs->file->bl.opt_transfer_length;
+ bs->bl.max_transfer_length = bs->file->bl.max_transfer_length;
+ bs->bl.min_mem_alignment = bs->file->bl.min_mem_alignment;
+ bs->bl.opt_mem_alignment = bs->file->bl.opt_mem_alignment;
+ } else {
+ bs->bl.min_mem_alignment = 512;
+ bs->bl.opt_mem_alignment = getpagesize();
+ }
+
+ if (bs->backing_hd) {
+ bdrv_refresh_limits(bs->backing_hd, &local_err);
+ if (local_err) {
+ error_propagate(errp, local_err);
+ return;
+ }
+ bs->bl.opt_transfer_length =
+ MAX(bs->bl.opt_transfer_length,
+ bs->backing_hd->bl.opt_transfer_length);
+ bs->bl.max_transfer_length =
+ MIN_NON_ZERO(bs->bl.max_transfer_length,
+ bs->backing_hd->bl.max_transfer_length);
+ bs->bl.opt_mem_alignment =
+ MAX(bs->bl.opt_mem_alignment,
+ bs->backing_hd->bl.opt_mem_alignment);
+ bs->bl.min_mem_alignment =
+ MAX(bs->bl.min_mem_alignment,
+ bs->backing_hd->bl.min_mem_alignment);
+ }
+
+ /* Then let the driver override it */
+ if (drv->bdrv_refresh_limits) {
+ drv->bdrv_refresh_limits(bs, errp);
+ }
+}
+
+/**
+ * The copy-on-read flag is actually a reference count so multiple users may
+ * use the feature without worrying about clobbering its previous state.
+ * Copy-on-read stays enabled until all users have called to disable it.
+ */
+void bdrv_enable_copy_on_read(BlockDriverState *bs)
+{
+ bs->copy_on_read++;
+}
+
+void bdrv_disable_copy_on_read(BlockDriverState *bs)
+{
+ assert(bs->copy_on_read > 0);
+ bs->copy_on_read--;
+}
+
+/* Check if any requests are in-flight (including throttled requests) */
+static bool bdrv_requests_pending(BlockDriverState *bs)
+{
+ if (!QLIST_EMPTY(&bs->tracked_requests)) {
+ return true;
+ }
+ if (!qemu_co_queue_empty(&bs->throttled_reqs[0])) {
+ return true;
+ }
+ if (!qemu_co_queue_empty(&bs->throttled_reqs[1])) {
+ return true;
+ }
+ if (bs->file && bdrv_requests_pending(bs->file)) {
+ return true;
+ }
+ if (bs->backing_hd && bdrv_requests_pending(bs->backing_hd)) {
+ return true;
+ }
+ return false;
+}
+
+/*
+ * Wait for pending requests to complete on a single BlockDriverState subtree
+ *
+ * Note that unlike bdrv_drain_all(), the caller must hold the BlockDriverState
+ * AioContext.
+ *
+ * Only this BlockDriverState's AioContext is run, so in-flight requests must
+ * not depend on events in other AioContexts. In that case, use
+ * bdrv_drain_all() instead.
+ */
+void bdrv_drain(BlockDriverState *bs)
+{
+ bool busy = true;
+
+ while (busy) {
+ /* Keep iterating */
+ bdrv_flush_io_queue(bs);
+ busy = bdrv_requests_pending(bs);
+ busy |= aio_poll(bdrv_get_aio_context(bs), busy);
+ }
+}
+
+/*
+ * 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.
+ */
+void bdrv_drain_all(void)
+{
+ /* Always run first iteration so any pending completion BHs run */
+ bool busy = true;
+ BlockDriverState *bs = NULL;
+ GSList *aio_ctxs = NULL, *ctx;
+
+ while ((bs = bdrv_next(bs))) {
+ AioContext *aio_context = bdrv_get_aio_context(bs);
+
+ aio_context_acquire(aio_context);
+ if (bs->job) {
+ block_job_pause(bs->job);
+ }
+ aio_context_release(aio_context);
+
+ if (!g_slist_find(aio_ctxs, aio_context)) {
+ aio_ctxs = g_slist_prepend(aio_ctxs, aio_context);
+ }
+ }
+
+ /* Note that completion of an asynchronous I/O operation can trigger any
+ * number of other I/O operations on other devices---for example a
+ * coroutine can submit an I/O request to another device in response to
+ * request completion. Therefore we must keep looping until there was no
+ * more activity rather than simply draining each device independently.
+ */
+ while (busy) {
+ busy = false;
+
+ for (ctx = aio_ctxs; ctx != NULL; ctx = ctx->next) {
+ AioContext *aio_context = ctx->data;
+ bs = NULL;
+
+ aio_context_acquire(aio_context);
+ while ((bs = bdrv_next(bs))) {
+ if (aio_context == bdrv_get_aio_context(bs)) {
+ bdrv_flush_io_queue(bs);
+ if (bdrv_requests_pending(bs)) {
+ busy = true;
+ aio_poll(aio_context, busy);
+ }
+ }
+ }
+ busy |= aio_poll(aio_context, false);
+ aio_context_release(aio_context);
+ }
+ }
+
+ bs = NULL;
+ while ((bs = bdrv_next(bs))) {
+ AioContext *aio_context = bdrv_get_aio_context(bs);
+
+ aio_context_acquire(aio_context);
+ if (bs->job) {
+ block_job_resume(bs->job);
+ }
+ aio_context_release(aio_context);
+ }
+ g_slist_free(aio_ctxs);
+}
+
+/**
+ * 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) {
+ req->bs->serialising_in_flight--;
+ }
+
+ QLIST_REMOVE(req, list);
+ qemu_co_queue_restart_all(&req->wait_queue);
+}
+
+/**
+ * Add an active request to the tracked requests list
+ */
+static void tracked_request_begin(BdrvTrackedRequest *req,
+ BlockDriverState *bs,
+ int64_t offset,
+ unsigned int bytes, bool is_write)
+{
+ *req = (BdrvTrackedRequest){
+ .bs = bs,
+ .offset = offset,
+ .bytes = bytes,
+ .is_write = is_write,
+ .co = qemu_coroutine_self(),
+ .serialising = false,
+ .overlap_offset = offset,
+ .overlap_bytes = bytes,
+ };
+
+ qemu_co_queue_init(&req->wait_queue);
+
+ QLIST_INSERT_HEAD(&bs->tracked_requests, req, list);
+}
+
+static void mark_request_serialising(BdrvTrackedRequest *req, uint64_t align)
+{
+ int64_t overlap_offset = req->offset & ~(align - 1);
+ unsigned int overlap_bytes = ROUND_UP(req->offset + req->bytes, align)
+ - overlap_offset;
+
+ if (!req->serialising) {
+ 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,
+ int64_t sector_num, int nb_sectors,
+ int64_t *cluster_sector_num,
+ int *cluster_nb_sectors)
+{
+ BlockDriverInfo bdi;
+
+ if (bdrv_get_info(bs, &bdi) < 0 || bdi.cluster_size == 0) {
+ *cluster_sector_num = sector_num;
+ *cluster_nb_sectors = nb_sectors;
+ } else {
+ int64_t c = bdi.cluster_size / BDRV_SECTOR_SIZE;
+ *cluster_sector_num = QEMU_ALIGN_DOWN(sector_num, c);
+ *cluster_nb_sectors = QEMU_ALIGN_UP(sector_num - *cluster_sector_num +
+ nb_sectors, 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->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;
+}
+
+static bool coroutine_fn wait_serialising_requests(BdrvTrackedRequest *self)
+{
+ BlockDriverState *bs = self->bs;
+ BdrvTrackedRequest *req;
+ bool retry;
+ bool waited = false;
+
+ if (!bs->serialising_in_flight) {
+ return 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);
+ self->waiting_for = NULL;
+ retry = true;
+ waited = true;
+ break;
+ }
+ }
+ }
+ } 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;
+}
+
+static int bdrv_check_request(BlockDriverState *bs, int64_t sector_num,
+ int nb_sectors)
+{
+ if (nb_sectors < 0 || nb_sectors > BDRV_REQUEST_MAX_SECTORS) {
+ return -EIO;
+ }
+
+ return bdrv_check_byte_request(bs, sector_num * BDRV_SECTOR_SIZE,
+ nb_sectors * BDRV_SECTOR_SIZE);
+}
+
+typedef struct RwCo {
+ BlockDriverState *bs;
+ 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_do_preadv(rwco->bs, rwco->offset,
+ rwco->qiov->size, rwco->qiov,
+ rwco->flags);
+ } else {
+ rwco->ret = bdrv_co_do_pwritev(rwco->bs, rwco->offset,
+ rwco->qiov->size, rwco->qiov,
+ rwco->flags);
+ }
+}
+
+/*
+ * Process a vectored synchronous request using coroutines
+ */
+static int bdrv_prwv_co(BlockDriverState *bs, int64_t offset,
+ QEMUIOVector *qiov, bool is_write,
+ BdrvRequestFlags flags)
+{
+ Coroutine *co;
+ RwCo rwco = {
+ .bs = bs,
+ .offset = offset,
+ .qiov = qiov,
+ .is_write = is_write,
+ .ret = NOT_DONE,
+ .flags = flags,
+ };
+
+ /**
+ * In sync call context, when the vcpu is blocked, this throttling timer
+ * will not fire; so the I/O throttling function has to be disabled here
+ * if it has been enabled.
+ */
+ if (bs->io_limits_enabled) {
+ fprintf(stderr, "Disabling I/O throttling on '%s' due "
+ "to synchronous I/O.\n", bdrv_get_device_name(bs));
+ bdrv_io_limits_disable(bs);
+ }
+
+ if (qemu_in_coroutine()) {
+ /* Fast-path if already in coroutine context */
+ bdrv_rw_co_entry(&rwco);
+ } else {
+ AioContext *aio_context = bdrv_get_aio_context(bs);
+
+ co = qemu_coroutine_create(bdrv_rw_co_entry);
+ qemu_coroutine_enter(co, &rwco);
+ while (rwco.ret == NOT_DONE) {
+ aio_poll(aio_context, true);
+ }
+ }
+ return rwco.ret;
+}
+
+/*
+ * Process a synchronous request using coroutines
+ */
+static int bdrv_rw_co(BlockDriverState *bs, 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(bs, sector_num << BDRV_SECTOR_BITS,
+ &qiov, is_write, flags);
+}
+
+/* return < 0 if error. See bdrv_write() for the return codes */
+int bdrv_read(BlockDriverState *bs, int64_t sector_num,
+ uint8_t *buf, int nb_sectors)
+{
+ return bdrv_rw_co(bs, sector_num, buf, nb_sectors, false, 0);
+}
+
+/* Just like bdrv_read(), but with I/O throttling temporarily disabled */
+int bdrv_read_unthrottled(BlockDriverState *bs, int64_t sector_num,
+ uint8_t *buf, int nb_sectors)
+{
+ bool enabled;
+ int ret;
+
+ enabled = bs->io_limits_enabled;
+ bs->io_limits_enabled = false;
+ ret = bdrv_read(bs, sector_num, buf, nb_sectors);
+ bs->io_limits_enabled = enabled;
+ return ret;
+}
+
+/* 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(BlockDriverState *bs, int64_t sector_num,
+ const uint8_t *buf, int nb_sectors)
+{
+ return bdrv_rw_co(bs, sector_num, (uint8_t *)buf, nb_sectors, true, 0);
+}
+
+int bdrv_write_zeroes(BlockDriverState *bs, int64_t sector_num,
+ int nb_sectors, BdrvRequestFlags flags)
+{
+ return bdrv_rw_co(bs, sector_num, NULL, nb_sectors, true,
+ BDRV_REQ_ZERO_WRITE | flags);
+}
+
+/*
+ * Completely zero out a block device with the help of bdrv_write_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_write_zeroes (e.g. BDRV_REQ_MAY_UNMAP).
+ *
+ * Returns < 0 on error, 0 on success. For error codes see bdrv_write().
+ */
+int bdrv_make_zero(BlockDriverState *bs, BdrvRequestFlags flags)
+{
+ int64_t target_sectors, ret, nb_sectors, sector_num = 0;
+ 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);
+ 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_write_zeroes(bs, sector_num, n, flags);
+ if (ret < 0) {
+ error_report("error writing zeroes at sector %" PRId64 ": %s",
+ sector_num, strerror(-ret));
+ return ret;
+ }
+ sector_num += n;
+ }
+}
+
+int bdrv_pread(BlockDriverState *bs, int64_t offset, void *buf, int bytes)
+{
+ QEMUIOVector qiov;
+ struct iovec iov = {
+ .iov_base = (void *)buf,
+ .iov_len = bytes,
+ };
+ int ret;
+
+ if (bytes < 0) {
+ return -EINVAL;
+ }
+
+ qemu_iovec_init_external(&qiov, &iov, 1);
+ ret = bdrv_prwv_co(bs, offset, &qiov, false, 0);
+ if (ret < 0) {
+ return ret;
+ }
+
+ return bytes;
+}
+
+int bdrv_pwritev(BlockDriverState *bs, int64_t offset, QEMUIOVector *qiov)
+{
+ int ret;
+
+ ret = bdrv_prwv_co(bs, offset, qiov, true, 0);
+ if (ret < 0) {
+ return ret;
+ }
+
+ return qiov->size;
+}
+
+int bdrv_pwrite(BlockDriverState *bs, 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(bs, 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(BlockDriverState *bs, int64_t offset,
+ const void *buf, int count)
+{
+ int ret;
+
+ ret = bdrv_pwrite(bs, offset, buf, count);
+ if (ret < 0) {
+ return ret;
+ }
+
+ /* No flush needed for cache modes that already do it */
+ if (bs->enable_write_cache) {
+ bdrv_flush(bs);
+ }
+
+ return 0;
+}
+
+static int coroutine_fn bdrv_co_do_copy_on_readv(BlockDriverState *bs,
+ int64_t sector_num, int nb_sectors, QEMUIOVector *qiov)
+{
+ /* 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_sector_num;
+ int cluster_nb_sectors;
+ size_t skip_bytes;
+ int ret;
+
+ /* Cover entire cluster so no additional backing file I/O is required when
+ * allocating cluster in the image file.
+ */
+ bdrv_round_to_clusters(bs, sector_num, nb_sectors,
+ &cluster_sector_num, &cluster_nb_sectors);
+
+ trace_bdrv_co_do_copy_on_readv(bs, sector_num, nb_sectors,
+ cluster_sector_num, cluster_nb_sectors);
+
+ iov.iov_len = cluster_nb_sectors * BDRV_SECTOR_SIZE;
+ 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 = drv->bdrv_co_readv(bs, cluster_sector_num, cluster_nb_sectors,
+ &bounce_qiov);
+ if (ret < 0) {
+ goto err;
+ }
+
+ if (drv->bdrv_co_write_zeroes &&
+ buffer_is_zero(bounce_buffer, iov.iov_len)) {
+ ret = bdrv_co_do_write_zeroes(bs, cluster_sector_num,
+ cluster_nb_sectors, 0);
+ } else {
+ /* This does not change the data on the disk, it is not necessary
+ * to flush even in cache=writethrough mode.
+ */
+ ret = drv->bdrv_co_writev(bs, cluster_sector_num, cluster_nb_sectors,
+ &bounce_qiov);
+ }
+
+ 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 = (sector_num - cluster_sector_num) * BDRV_SECTOR_SIZE;
+ qemu_iovec_from_buf(qiov, 0, bounce_buffer + skip_bytes,
+ nb_sectors * BDRV_SECTOR_SIZE);
+
+err:
+ qemu_vfree(bounce_buffer);
+ return ret;
+}
+
+/*
+ * Forwards an already correctly aligned request to the BlockDriver. This
+ * handles copy on read and zeroing after EOF; any other features must be
+ * implemented by the caller.
+ */
+static int coroutine_fn bdrv_aligned_preadv(BlockDriverState *bs,
+ BdrvTrackedRequest *req, int64_t offset, unsigned int bytes,
+ int64_t align, QEMUIOVector *qiov, int flags)
+{
+ BlockDriver *drv = bs->drv;
+ int ret;
+
+ int64_t sector_num = offset >> BDRV_SECTOR_BITS;
+ unsigned int nb_sectors = bytes >> BDRV_SECTOR_BITS;
+
+ assert((offset & (BDRV_SECTOR_SIZE - 1)) == 0);
+ assert((bytes & (BDRV_SECTOR_SIZE - 1)) == 0);
+ assert(!qiov || bytes == qiov->size);
+
+ /* 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));
+ }
+
+ wait_serialising_requests(req);
+
+ if (flags & BDRV_REQ_COPY_ON_READ) {
+ int pnum;
+
+ ret = bdrv_is_allocated(bs, sector_num, nb_sectors, &pnum);
+ if (ret < 0) {
+ goto out;
+ }
+
+ if (!ret || pnum != nb_sectors) {
+ ret = bdrv_co_do_copy_on_readv(bs, sector_num, nb_sectors, qiov);
+ goto out;
+ }
+ }
+
+ /* Forward the request to the BlockDriver */
+ if (!bs->zero_beyond_eof) {
+ ret = drv->bdrv_co_readv(bs, sector_num, nb_sectors, qiov);
+ } else {
+ /* Read zeros after EOF */
+ int64_t total_sectors, max_nb_sectors;
+
+ total_sectors = bdrv_nb_sectors(bs);
+ if (total_sectors < 0) {
+ ret = total_sectors;
+ goto out;
+ }
+
+ max_nb_sectors = ROUND_UP(MAX(0, total_sectors - sector_num),
+ align >> BDRV_SECTOR_BITS);
+ if (nb_sectors < max_nb_sectors) {
+ ret = drv->bdrv_co_readv(bs, sector_num, nb_sectors, qiov);
+ } else if (max_nb_sectors > 0) {
+ QEMUIOVector local_qiov;
+
+ qemu_iovec_init(&local_qiov, qiov->niov);
+ qemu_iovec_concat(&local_qiov, qiov, 0,
+ max_nb_sectors * BDRV_SECTOR_SIZE);
+
+ ret = drv->bdrv_co_readv(bs, sector_num, max_nb_sectors,
+ &local_qiov);
+
+ qemu_iovec_destroy(&local_qiov);
+ } else {
+ ret = 0;
+ }
+
+ /* Reading beyond end of file is supposed to produce zeroes */
+ if (ret == 0 && total_sectors < sector_num + nb_sectors) {
+ uint64_t offset = MAX(0, total_sectors - sector_num);
+ uint64_t bytes = (sector_num + nb_sectors - offset) *
+ BDRV_SECTOR_SIZE;
+ qemu_iovec_memset(qiov, offset * BDRV_SECTOR_SIZE, 0, bytes);
+ }
+ }
+
+out:
+ return ret;
+}
+
+/*
+ * Handle a read request in coroutine context
+ */
+static int coroutine_fn bdrv_co_do_preadv(BlockDriverState *bs,
+ int64_t offset, unsigned int bytes, QEMUIOVector *qiov,
+ BdrvRequestFlags flags)
+{
+ BlockDriver *drv = bs->drv;
+ BdrvTrackedRequest req;
+
+ /* TODO Lift BDRV_SECTOR_SIZE restriction in BlockDriver interface */
+ uint64_t align = MAX(BDRV_SECTOR_SIZE, bs->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;
+ }
+
+ if (bs->copy_on_read) {
+ flags |= BDRV_REQ_COPY_ON_READ;
+ }
+
+ /* throttling disk I/O */
+ if (bs->io_limits_enabled) {
+ throttle_group_co_io_limits_intercept(bs, bytes, false);
+ }
+
+ /* 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, false);
+ ret = bdrv_aligned_preadv(bs, &req, offset, bytes, align,
+ use_local_qiov ? &local_qiov : qiov,
+ flags);
+ tracked_request_end(&req);
+
+ 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(BlockDriverState *bs,
+ 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_do_preadv(bs, sector_num << BDRV_SECTOR_BITS,
+ nb_sectors << BDRV_SECTOR_BITS, qiov, flags);
+}
+
+int coroutine_fn bdrv_co_readv(BlockDriverState *bs, int64_t sector_num,
+ int nb_sectors, QEMUIOVector *qiov)
+{
+ trace_bdrv_co_readv(bs, sector_num, nb_sectors);
+
+ return bdrv_co_do_readv(bs, sector_num, nb_sectors, qiov, 0);
+}
+
+int coroutine_fn bdrv_co_copy_on_readv(BlockDriverState *bs,
+ int64_t sector_num, int nb_sectors, QEMUIOVector *qiov)
+{
+ trace_bdrv_co_copy_on_readv(bs, sector_num, nb_sectors);
+
+ return bdrv_co_do_readv(bs, sector_num, nb_sectors, qiov,
+ BDRV_REQ_COPY_ON_READ);
+}
+
+#define MAX_WRITE_ZEROES_BOUNCE_BUFFER 32768
+
+static int coroutine_fn bdrv_co_do_write_zeroes(BlockDriverState *bs,
+ int64_t sector_num, int nb_sectors, BdrvRequestFlags flags)
+{
+ BlockDriver *drv = bs->drv;
+ QEMUIOVector qiov;
+ struct iovec iov = {0};
+ int ret = 0;
+
+ int max_write_zeroes = MIN_NON_ZERO(bs->bl.max_write_zeroes,
+ BDRV_REQUEST_MAX_SECTORS);
+
+ while (nb_sectors > 0 && !ret) {
+ int num = nb_sectors;
+
+ /* Align request. Block drivers can expect the "bulk" of the request
+ * to be aligned.
+ */
+ if (bs->bl.write_zeroes_alignment
+ && num > bs->bl.write_zeroes_alignment) {
+ if (sector_num % bs->bl.write_zeroes_alignment != 0) {
+ /* Make a small request up to the first aligned sector. */
+ num = bs->bl.write_zeroes_alignment;
+ num -= sector_num % bs->bl.write_zeroes_alignment;
+ } else if ((sector_num + num) % bs->bl.write_zeroes_alignment != 0) {
+ /* Shorten the request to the last aligned sector. num cannot
+ * underflow because num > bs->bl.write_zeroes_alignment.
+ */
+ num -= (sector_num + num) % bs->bl.write_zeroes_alignment;
+ }
+ }
+
+ /* 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_write_zeroes) {
+ ret = drv->bdrv_co_write_zeroes(bs, sector_num, num, flags);
+ }
+
+ if (ret == -ENOTSUP) {
+ /* Fall back to bounce buffer if write zeroes is unsupported */
+ int max_xfer_len = MIN_NON_ZERO(bs->bl.max_transfer_length,
+ MAX_WRITE_ZEROES_BOUNCE_BUFFER);
+ num = MIN(num, max_xfer_len);
+ iov.iov_len = num * BDRV_SECTOR_SIZE;
+ if (iov.iov_base == NULL) {
+ iov.iov_base = qemu_try_blockalign(bs, num * BDRV_SECTOR_SIZE);
+ if (iov.iov_base == NULL) {
+ ret = -ENOMEM;
+ goto fail;
+ }
+ memset(iov.iov_base, 0, num * BDRV_SECTOR_SIZE);
+ }
+ qemu_iovec_init_external(&qiov, &iov, 1);
+
+ ret = drv->bdrv_co_writev(bs, sector_num, num, &qiov);
+
+ /* Keep bounce buffer around if it is big enough for all
+ * all future requests.
+ */
+ if (num < max_xfer_len) {
+ qemu_vfree(iov.iov_base);
+ iov.iov_base = NULL;
+ }
+ }
+
+ sector_num += num;
+ nb_sectors -= num;
+ }
+
+fail:
+ qemu_vfree(iov.iov_base);
+ return ret;
+}
+
+/*
+ * Forwards an already correctly aligned write request to the BlockDriver.
+ */
+static int coroutine_fn bdrv_aligned_pwritev(BlockDriverState *bs,
+ BdrvTrackedRequest *req, int64_t offset, unsigned int bytes,
+ QEMUIOVector *qiov, int flags)
+{
+ BlockDriver *drv = bs->drv;
+ bool waited;
+ int ret;
+
+ int64_t sector_num = offset >> BDRV_SECTOR_BITS;
+ unsigned int nb_sectors = bytes >> BDRV_SECTOR_BITS;
+
+ assert((offset & (BDRV_SECTOR_SIZE - 1)) == 0);
+ assert((bytes & (BDRV_SECTOR_SIZE - 1)) == 0);
+ assert(!qiov || bytes == qiov->size);
+
+ waited = wait_serialising_requests(req);
+ assert(!waited || !req->serialising);
+ assert(req->overlap_offset <= offset);
+ assert(offset + bytes <= req->overlap_offset + req->overlap_bytes);
+
+ 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_write_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) {
+ BLKDBG_EVENT(bs, BLKDBG_PWRITEV_ZERO);
+ ret = bdrv_co_do_write_zeroes(bs, sector_num, nb_sectors, flags);
+ } else {
+ BLKDBG_EVENT(bs, BLKDBG_PWRITEV);
+ ret = drv->bdrv_co_writev(bs, sector_num, nb_sectors, qiov);
+ }
+ BLKDBG_EVENT(bs, BLKDBG_PWRITEV_DONE);
+
+ if (ret == 0 && !bs->enable_write_cache) {
+ ret = bdrv_co_flush(bs);
+ }
+
+ bdrv_set_dirty(bs, sector_num, nb_sectors);
+
+ block_acct_highest_sector(&bs->stats, sector_num, nb_sectors);
+
+ if (ret >= 0) {
+ bs->total_sectors = MAX(bs->total_sectors, sector_num + nb_sectors);
+ }
+
+ return ret;
+}
+
+static int coroutine_fn bdrv_co_do_zero_pwritev(BlockDriverState *bs,
+ int64_t offset,
+ unsigned int bytes,
+ BdrvRequestFlags flags,
+ BdrvTrackedRequest *req)
+{
+ uint8_t *buf = NULL;
+ QEMUIOVector local_qiov;
+ struct iovec iov;
+ uint64_t align = MAX(BDRV_SECTOR_SIZE, bs->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);
+ BLKDBG_EVENT(bs, BLKDBG_PWRITEV_RMW_HEAD);
+ ret = bdrv_aligned_preadv(bs, req, offset & ~(align - 1), align,
+ align, &local_qiov, 0);
+ if (ret < 0) {
+ goto fail;
+ }
+ BLKDBG_EVENT(bs, BLKDBG_PWRITEV_RMW_AFTER_HEAD);
+
+ memset(buf + head_padding_bytes, 0, zero_bytes);
+ ret = bdrv_aligned_pwritev(bs, req, offset & ~(align - 1), 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(bs, req, offset, aligned_bytes,
+ 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);
+ BLKDBG_EVENT(bs, BLKDBG_PWRITEV_RMW_TAIL);
+ ret = bdrv_aligned_preadv(bs, req, offset, align,
+ align, &local_qiov, 0);
+ if (ret < 0) {
+ goto fail;
+ }
+ BLKDBG_EVENT(bs, BLKDBG_PWRITEV_RMW_AFTER_TAIL);
+
+ memset(buf, 0, bytes);
+ ret = bdrv_aligned_pwritev(bs, req, offset, align,
+ &local_qiov, flags & ~BDRV_REQ_ZERO_WRITE);
+ }
+fail:
+ qemu_vfree(buf);
+ return ret;
+
+}
+
+/*
+ * Handle a write request in coroutine context
+ */
+static int coroutine_fn bdrv_co_do_pwritev(BlockDriverState *bs,
+ int64_t offset, unsigned int bytes, QEMUIOVector *qiov,
+ BdrvRequestFlags flags)
+{
+ BdrvTrackedRequest req;
+ /* TODO Lift BDRV_SECTOR_SIZE restriction in BlockDriver interface */
+ uint64_t align = MAX(BDRV_SECTOR_SIZE, bs->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;
+ }
+
+ ret = bdrv_check_byte_request(bs, offset, bytes);
+ if (ret < 0) {
+ return ret;
+ }
+
+ /* throttling disk I/O */
+ if (bs->io_limits_enabled) {
+ throttle_group_co_io_limits_intercept(bs, bytes, true);
+ }
+
+ /*
+ * 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, true);
+
+ if (!qiov) {
+ ret = bdrv_co_do_zero_pwritev(bs, 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);
+
+ BLKDBG_EVENT(bs, BLKDBG_PWRITEV_RMW_HEAD);
+ ret = bdrv_aligned_preadv(bs, &req, offset & ~(align - 1), align,
+ align, &head_qiov, 0);
+ if (ret < 0) {
+ goto fail;
+ }
+ BLKDBG_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);
+ }
+
+ 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);
+
+ BLKDBG_EVENT(bs, BLKDBG_PWRITEV_RMW_TAIL);
+ ret = bdrv_aligned_preadv(bs, &req, (offset + bytes) & ~(align - 1), align,
+ align, &tail_qiov, 0);
+ if (ret < 0) {
+ goto fail;
+ }
+ BLKDBG_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(bs, &req, offset, bytes,
+ 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);
+ return ret;
+}
+
+static int coroutine_fn bdrv_co_do_writev(BlockDriverState *bs,
+ 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_do_pwritev(bs, sector_num << BDRV_SECTOR_BITS,
+ nb_sectors << BDRV_SECTOR_BITS, qiov, flags);
+}
+
+int coroutine_fn bdrv_co_writev(BlockDriverState *bs, int64_t sector_num,
+ int nb_sectors, QEMUIOVector *qiov)
+{
+ trace_bdrv_co_writev(bs, sector_num, nb_sectors);
+
+ return bdrv_co_do_writev(bs, sector_num, nb_sectors, qiov, 0);
+}
+
+int coroutine_fn bdrv_co_write_zeroes(BlockDriverState *bs,
+ int64_t sector_num, int nb_sectors,
+ BdrvRequestFlags flags)
+{
+ trace_bdrv_co_write_zeroes(bs, sector_num, nb_sectors, flags);
+
+ if (!(bs->open_flags & BDRV_O_UNMAP)) {
+ flags &= ~BDRV_REQ_MAY_UNMAP;
+ }
+
+ return bdrv_co_do_writev(bs, sector_num, nb_sectors, NULL,
+ BDRV_REQ_ZERO_WRITE | flags);
+}
+
+int bdrv_flush_all(void)
+{
+ BlockDriverState *bs = NULL;
+ int result = 0;
+
+ while ((bs = bdrv_next(bs))) {
+ 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;
+ 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 0
+ * 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.
+ */
+static int64_t coroutine_fn bdrv_co_get_block_status(BlockDriverState *bs,
+ int64_t sector_num,
+ int nb_sectors, int *pnum)
+{
+ int64_t total_sectors;
+ int64_t n;
+ int64_t ret, ret2;
+
+ total_sectors = bdrv_nb_sectors(bs);
+ if (total_sectors < 0) {
+ return total_sectors;
+ }
+
+ if (sector_num >= total_sectors) {
+ *pnum = 0;
+ return 0;
+ }
+
+ 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 (bs->drv->protocol_name) {
+ ret |= BDRV_BLOCK_OFFSET_VALID | (sector_num * BDRV_SECTOR_SIZE);
+ }
+ return ret;
+ }
+
+ ret = bs->drv->bdrv_co_get_block_status(bs, sector_num, nb_sectors, pnum);
+ if (ret < 0) {
+ *pnum = 0;
+ return ret;
+ }
+
+ if (ret & BDRV_BLOCK_RAW) {
+ assert(ret & BDRV_BLOCK_OFFSET_VALID);
+ return bdrv_get_block_status(bs->file, ret >> BDRV_SECTOR_BITS,
+ *pnum, pnum);
+ }
+
+ 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_hd) {
+ BlockDriverState *bs2 = bs->backing_hd;
+ int64_t nb_sectors2 = bdrv_nb_sectors(bs2);
+ if (nb_sectors2 >= 0 && sector_num >= nb_sectors2) {
+ ret |= BDRV_BLOCK_ZERO;
+ }
+ }
+ }
+
+ if (bs->file &&
+ (ret & BDRV_BLOCK_DATA) && !(ret & BDRV_BLOCK_ZERO) &&
+ (ret & BDRV_BLOCK_OFFSET_VALID)) {
+ int file_pnum;
+
+ ret2 = bdrv_co_get_block_status(bs->file, ret >> BDRV_SECTOR_BITS,
+ *pnum, &file_pnum);
+ if (ret2 >= 0) {
+ /* Ignore errors. This is just providing extra information, it
+ * is useful but not necessary.
+ */
+ if (!file_pnum) {
+ /* !file_pnum indicates an offset at or beyond the EOF; it is
+ * perfectly valid for the format block driver to point to such
+ * offsets, so catch it and mark everything 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);
+ }
+ }
+ }
+
+ 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 *p;
+ int64_t ret = 0;
+
+ assert(bs != base);
+ for (p = bs; p != base; p = p->backing_hd) {
+ ret = bdrv_co_get_block_status(p, sector_num, nb_sectors, pnum);
+ if (ret < 0 || ret & BDRV_BLOCK_ALLOCATED) {
+ 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);
+ }
+ 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->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)
+{
+ Coroutine *co;
+ BdrvCoGetBlockStatusData data = {
+ .bs = bs,
+ .base = base,
+ .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 {
+ AioContext *aio_context = bdrv_get_aio_context(bs);
+
+ co = qemu_coroutine_create(bdrv_get_block_status_above_co_entry);
+ qemu_coroutine_enter(co, &data);
+ while (!data.done) {
+ aio_poll(aio_context, true);
+ }
+ }
+ return data.ret;
+}
+
+int64_t bdrv_get_block_status(BlockDriverState *bs,
+ int64_t sector_num,
+ int nb_sectors, int *pnum)
+{
+ return bdrv_get_block_status_above(bs, bs->backing_hd,
+ sector_num, nb_sectors, pnum);
+}
+
+int coroutine_fn bdrv_is_allocated(BlockDriverState *bs, int64_t sector_num,
+ int nb_sectors, int *pnum)
+{
+ int64_t ret = bdrv_get_block_status(bs, sector_num, nb_sectors, pnum);
+ if (ret < 0) {
+ return ret;
+ }
+ return !!(ret & BDRV_BLOCK_ALLOCATED);
+}
+
+/*
+ * Given an image chain: ... -> [BASE] -> [INTER1] -> [INTER2] -> [TOP]
+ *
+ * Return true if the given sector is allocated in any image between
+ * BASE and TOP (inclusive). BASE can be NULL to check if the given
+ * sector is allocated in any image of the chain. Return false otherwise.
+ *
+ * '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.
+ *
+ */
+int bdrv_is_allocated_above(BlockDriverState *top,
+ BlockDriverState *base,
+ int64_t sector_num,
+ int nb_sectors, int *pnum)
+{
+ BlockDriverState *intermediate;
+ int ret, n = nb_sectors;
+
+ intermediate = top;
+ while (intermediate && intermediate != base) {
+ int pnum_inter;
+ ret = bdrv_is_allocated(intermediate, sector_num, nb_sectors,
+ &pnum_inter);
+ if (ret < 0) {
+ return ret;
+ } else if (ret) {
+ *pnum = pnum_inter;
+ return 1;
+ }
+
+ /*
+ * [sector_num, nb_sectors] is unallocated on top but intermediate
+ * might have
+ *
+ * [sector_num+x, nr_sectors] allocated.
+ */
+ if (n > pnum_inter &&
+ (intermediate == top ||
+ sector_num + pnum_inter < intermediate->total_sectors)) {
+ n = pnum_inter;
+ }
+
+ intermediate = intermediate->backing_hd;
+ }
+
+ *pnum = n;
+ return 0;
+}
+
+int bdrv_write_compressed(BlockDriverState *bs, int64_t sector_num,
+ const uint8_t *buf, int nb_sectors)
+{
+ BlockDriver *drv = bs->drv;
+ int ret;
+
+ if (!drv) {
+ return -ENOMEDIUM;
+ }
+ if (!drv->bdrv_write_compressed) {
+ return -ENOTSUP;
+ }
+ ret = bdrv_check_request(bs, sector_num, nb_sectors);
+ if (ret < 0) {
+ return ret;
+ }
+
+ assert(QLIST_EMPTY(&bs->dirty_bitmaps));
+
+ return drv->bdrv_write_compressed(bs, sector_num, buf, nb_sectors);
+}
+
+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,
+ };
+
+ qemu_iovec_init_external(&qiov, &iov, 1);
+ return bdrv_writev_vmstate(bs, &qiov, pos);
+}
+
+int bdrv_writev_vmstate(BlockDriverState *bs, QEMUIOVector *qiov, int64_t pos)
+{
+ BlockDriver *drv = bs->drv;
+
+ if (!drv) {
+ return -ENOMEDIUM;
+ } else if (drv->bdrv_save_vmstate) {
+ return drv->bdrv_save_vmstate(bs, qiov, pos);
+ } else if (bs->file) {
+ return bdrv_writev_vmstate(bs->file, qiov, pos);
+ }
+
+ return -ENOTSUP;
+}
+
+int bdrv_load_vmstate(BlockDriverState *bs, uint8_t *buf,
+ int64_t pos, int size)
+{
+ BlockDriver *drv = bs->drv;
+ if (!drv)
+ return -ENOMEDIUM;
+ if (drv->bdrv_load_vmstate)
+ return drv->bdrv_load_vmstate(bs, buf, pos, size);
+ if (bs->file)
+ return bdrv_load_vmstate(bs->file, buf, pos, size);
+ return -ENOTSUP;
+}
+
+/**************************************************************/
+/* async I/Os */
+
+BlockAIOCB *bdrv_aio_readv(BlockDriverState *bs, int64_t sector_num,
+ QEMUIOVector *qiov, int nb_sectors,
+ BlockCompletionFunc *cb, void *opaque)
+{
+ trace_bdrv_aio_readv(bs, sector_num, nb_sectors, opaque);
+
+ return bdrv_co_aio_rw_vector(bs, sector_num, qiov, nb_sectors, 0,
+ cb, opaque, false);
+}
+
+BlockAIOCB *bdrv_aio_writev(BlockDriverState *bs, int64_t sector_num,
+ QEMUIOVector *qiov, int nb_sectors,
+ BlockCompletionFunc *cb, void *opaque)
+{
+ trace_bdrv_aio_writev(bs, sector_num, nb_sectors, opaque);
+
+ return bdrv_co_aio_rw_vector(bs, sector_num, qiov, nb_sectors, 0,
+ cb, opaque, true);
+}
+
+BlockAIOCB *bdrv_aio_write_zeroes(BlockDriverState *bs,
+ int64_t sector_num, int nb_sectors, BdrvRequestFlags flags,
+ BlockCompletionFunc *cb, void *opaque)
+{
+ trace_bdrv_aio_write_zeroes(bs, sector_num, nb_sectors, flags, opaque);
+
+ return bdrv_co_aio_rw_vector(bs, sector_num, NULL, nb_sectors,
+ BDRV_REQ_ZERO_WRITE | flags,
+ cb, opaque, true);
+}
+
+
+typedef struct MultiwriteCB {
+ int error;
+ int num_requests;
+ int num_callbacks;
+ struct {
+ BlockCompletionFunc *cb;
+ void *opaque;
+ QEMUIOVector *free_qiov;
+ } callbacks[];
+} MultiwriteCB;
+
+static void multiwrite_user_cb(MultiwriteCB *mcb)
+{
+ int i;
+
+ for (i = 0; i < mcb->num_callbacks; i++) {
+ mcb->callbacks[i].cb(mcb->callbacks[i].opaque, mcb->error);
+ if (mcb->callbacks[i].free_qiov) {
+ qemu_iovec_destroy(mcb->callbacks[i].free_qiov);
+ }
+ g_free(mcb->callbacks[i].free_qiov);
+ }
+}
+
+static void multiwrite_cb(void *opaque, int ret)
+{
+ MultiwriteCB *mcb = opaque;
+
+ trace_multiwrite_cb(mcb, ret);
+
+ if (ret < 0 && !mcb->error) {
+ mcb->error = ret;
+ }
+
+ mcb->num_requests--;
+ if (mcb->num_requests == 0) {
+ multiwrite_user_cb(mcb);
+ g_free(mcb);
+ }
+}
+
+static int multiwrite_req_compare(const void *a, const void *b)
+{
+ const BlockRequest *req1 = a, *req2 = b;
+
+ /*
+ * Note that we can't simply subtract req2->sector from req1->sector
+ * here as that could overflow the return value.
+ */
+ if (req1->sector > req2->sector) {
+ return 1;
+ } else if (req1->sector < req2->sector) {
+ return -1;
+ } else {
+ return 0;
+ }
+}
+
+/*
+ * Takes a bunch of requests and tries to merge them. Returns the number of
+ * requests that remain after merging.
+ */
+static int multiwrite_merge(BlockDriverState *bs, BlockRequest *reqs,
+ int num_reqs, MultiwriteCB *mcb)
+{
+ int i, outidx;
+
+ // Sort requests by start sector
+ qsort(reqs, num_reqs, sizeof(*reqs), &multiwrite_req_compare);
+
+ // Check if adjacent requests touch the same clusters. If so, combine them,
+ // filling up gaps with zero sectors.
+ outidx = 0;
+ for (i = 1; i < num_reqs; i++) {
+ int merge = 0;
+ int64_t oldreq_last = reqs[outidx].sector + reqs[outidx].nb_sectors;
+
+ // Handle exactly sequential writes and overlapping writes.
+ if (reqs[i].sector <= oldreq_last) {
+ merge = 1;
+ }
+
+ if (reqs[outidx].qiov->niov + reqs[i].qiov->niov + 1 > IOV_MAX) {
+ merge = 0;
+ }
+
+ if (bs->bl.max_transfer_length && reqs[outidx].nb_sectors +
+ reqs[i].nb_sectors > bs->bl.max_transfer_length) {
+ merge = 0;
+ }
+
+ if (merge) {
+ size_t size;
+ QEMUIOVector *qiov = g_malloc0(sizeof(*qiov));
+ qemu_iovec_init(qiov,
+ reqs[outidx].qiov->niov + reqs[i].qiov->niov + 1);
+
+ // Add the first request to the merged one. If the requests are
+ // overlapping, drop the last sectors of the first request.
+ size = (reqs[i].sector - reqs[outidx].sector) << 9;
+ qemu_iovec_concat(qiov, reqs[outidx].qiov, 0, size);
+
+ // We should need to add any zeros between the two requests
+ assert (reqs[i].sector <= oldreq_last);
+
+ // Add the second request
+ qemu_iovec_concat(qiov, reqs[i].qiov, 0, reqs[i].qiov->size);
+
+ // Add tail of first request, if necessary
+ if (qiov->size < reqs[outidx].qiov->size) {
+ qemu_iovec_concat(qiov, reqs[outidx].qiov, qiov->size,
+ reqs[outidx].qiov->size - qiov->size);
+ }
+
+ reqs[outidx].nb_sectors = qiov->size >> 9;
+ reqs[outidx].qiov = qiov;
+
+ mcb->callbacks[i].free_qiov = reqs[outidx].qiov;
+ } else {
+ outidx++;
+ reqs[outidx].sector = reqs[i].sector;
+ reqs[outidx].nb_sectors = reqs[i].nb_sectors;
+ reqs[outidx].qiov = reqs[i].qiov;
+ }
+ }
+
+ block_acct_merge_done(&bs->stats, BLOCK_ACCT_WRITE, num_reqs - outidx - 1);
+
+ return outidx + 1;
+}
+
+/*
+ * Submit multiple AIO write requests at once.
+ *
+ * On success, the function returns 0 and all requests in the reqs array have
+ * been submitted. In error case this function returns -1, and any of the
+ * requests may or may not be submitted yet. In particular, this means that the
+ * callback will be called for some of the requests, for others it won't. The
+ * caller must check the error field of the BlockRequest to wait for the right
+ * callbacks (if error != 0, no callback will be called).
+ *
+ * The implementation may modify the contents of the reqs array, e.g. to merge
+ * requests. However, the fields opaque and error are left unmodified as they
+ * are used to signal failure for a single request to the caller.
+ */
+int bdrv_aio_multiwrite(BlockDriverState *bs, BlockRequest *reqs, int num_reqs)
+{
+ MultiwriteCB *mcb;
+ int i;
+
+ /* don't submit writes if we don't have a medium */
+ if (bs->drv == NULL) {
+ for (i = 0; i < num_reqs; i++) {
+ reqs[i].error = -ENOMEDIUM;
+ }
+ return -1;
+ }
+
+ if (num_reqs == 0) {
+ return 0;
+ }
+
+ // Create MultiwriteCB structure
+ mcb = g_malloc0(sizeof(*mcb) + num_reqs * sizeof(*mcb->callbacks));
+ mcb->num_requests = 0;
+ mcb->num_callbacks = num_reqs;
+
+ for (i = 0; i < num_reqs; i++) {
+ mcb->callbacks[i].cb = reqs[i].cb;
+ mcb->callbacks[i].opaque = reqs[i].opaque;
+ }
+
+ // Check for mergable requests
+ num_reqs = multiwrite_merge(bs, reqs, num_reqs, mcb);
+
+ trace_bdrv_aio_multiwrite(mcb, mcb->num_callbacks, num_reqs);
+
+ /* Run the aio requests. */
+ mcb->num_requests = num_reqs;
+ for (i = 0; i < num_reqs; i++) {
+ bdrv_co_aio_rw_vector(bs, reqs[i].sector, reqs[i].qiov,
+ reqs[i].nb_sectors, reqs[i].flags,
+ multiwrite_cb, mcb,
+ true);
+ }
+
+ return 0;
+}
+
+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) {
+ 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);
+ }
+}
+
+/**************************************************************/
+/* async block device emulation */
+
+typedef struct BlockAIOCBSync {
+ BlockAIOCB common;
+ QEMUBH *bh;
+ int ret;
+ /* vector translation state */
+ QEMUIOVector *qiov;
+ uint8_t *bounce;
+ int is_write;
+} BlockAIOCBSync;
+
+static const AIOCBInfo bdrv_em_aiocb_info = {
+ .aiocb_size = sizeof(BlockAIOCBSync),
+};
+
+static void bdrv_aio_bh_cb(void *opaque)
+{
+ BlockAIOCBSync *acb = opaque;
+
+ if (!acb->is_write && acb->ret >= 0) {
+ qemu_iovec_from_buf(acb->qiov, 0, acb->bounce, acb->qiov->size);
+ }
+ qemu_vfree(acb->bounce);
+ acb->common.cb(acb->common.opaque, acb->ret);
+ qemu_bh_delete(acb->bh);
+ acb->bh = NULL;
+ qemu_aio_unref(acb);
+}
+
+static BlockAIOCB *bdrv_aio_rw_vector(BlockDriverState *bs,
+ int64_t sector_num,
+ QEMUIOVector *qiov,
+ int nb_sectors,
+ BlockCompletionFunc *cb,
+ void *opaque,
+ int is_write)
+
+{
+ BlockAIOCBSync *acb;
+
+ acb = qemu_aio_get(&bdrv_em_aiocb_info, bs, cb, opaque);
+ acb->is_write = is_write;
+ acb->qiov = qiov;
+ acb->bounce = qemu_try_blockalign(bs, qiov->size);
+ acb->bh = aio_bh_new(bdrv_get_aio_context(bs), bdrv_aio_bh_cb, acb);
+
+ if (acb->bounce == NULL) {
+ acb->ret = -ENOMEM;
+ } else if (is_write) {
+ qemu_iovec_to_buf(acb->qiov, 0, acb->bounce, qiov->size);
+ acb->ret = bs->drv->bdrv_write(bs, sector_num, acb->bounce, nb_sectors);
+ } else {
+ acb->ret = bs->drv->bdrv_read(bs, sector_num, acb->bounce, nb_sectors);
+ }
+
+ qemu_bh_schedule(acb->bh);
+
+ return &acb->common;
+}
+
+static BlockAIOCB *bdrv_aio_readv_em(BlockDriverState *bs,
+ int64_t sector_num, QEMUIOVector *qiov, int nb_sectors,
+ BlockCompletionFunc *cb, void *opaque)
+{
+ return bdrv_aio_rw_vector(bs, sector_num, qiov, nb_sectors, cb, opaque, 0);
+}
+
+static BlockAIOCB *bdrv_aio_writev_em(BlockDriverState *bs,
+ int64_t sector_num, QEMUIOVector *qiov, int nb_sectors,
+ BlockCompletionFunc *cb, void *opaque)
+{
+ return bdrv_aio_rw_vector(bs, sector_num, qiov, nb_sectors, cb, opaque, 1);
+}
+
+
+typedef struct BlockAIOCBCoroutine {
+ BlockAIOCB common;
+ BlockRequest req;
+ bool is_write;
+ bool need_bh;
+ bool *done;
+ QEMUBH* bh;
+} BlockAIOCBCoroutine;
+
+static const AIOCBInfo bdrv_em_co_aiocb_info = {
+ .aiocb_size = sizeof(BlockAIOCBCoroutine),
+};
+
+static void bdrv_co_complete(BlockAIOCBCoroutine *acb)
+{
+ if (!acb->need_bh) {
+ acb->common.cb(acb->common.opaque, acb->req.error);
+ qemu_aio_unref(acb);
+ }
+}
+
+static void bdrv_co_em_bh(void *opaque)
+{
+ BlockAIOCBCoroutine *acb = opaque;
+
+ assert(!acb->need_bh);
+ qemu_bh_delete(acb->bh);
+ bdrv_co_complete(acb);
+}
+
+static void bdrv_co_maybe_schedule_bh(BlockAIOCBCoroutine *acb)
+{
+ acb->need_bh = false;
+ if (acb->req.error != -EINPROGRESS) {
+ BlockDriverState *bs = acb->common.bs;
+
+ acb->bh = aio_bh_new(bdrv_get_aio_context(bs), bdrv_co_em_bh, acb);
+ qemu_bh_schedule(acb->bh);
+ }
+}
+
+/* Invoke bdrv_co_do_readv/bdrv_co_do_writev */
+static void coroutine_fn bdrv_co_do_rw(void *opaque)
+{
+ BlockAIOCBCoroutine *acb = opaque;
+ BlockDriverState *bs = acb->common.bs;
+
+ if (!acb->is_write) {
+ acb->req.error = bdrv_co_do_readv(bs, acb->req.sector,
+ acb->req.nb_sectors, acb->req.qiov, acb->req.flags);
+ } else {
+ acb->req.error = bdrv_co_do_writev(bs, acb->req.sector,
+ acb->req.nb_sectors, acb->req.qiov, acb->req.flags);
+ }
+
+ bdrv_co_complete(acb);
+}
+
+static BlockAIOCB *bdrv_co_aio_rw_vector(BlockDriverState *bs,
+ int64_t sector_num,
+ QEMUIOVector *qiov,
+ int nb_sectors,
+ BdrvRequestFlags flags,
+ BlockCompletionFunc *cb,
+ void *opaque,
+ bool is_write)
+{
+ Coroutine *co;
+ BlockAIOCBCoroutine *acb;
+
+ acb = qemu_aio_get(&bdrv_em_co_aiocb_info, bs, cb, opaque);
+ acb->need_bh = true;
+ acb->req.error = -EINPROGRESS;
+ acb->req.sector = sector_num;
+ acb->req.nb_sectors = nb_sectors;
+ acb->req.qiov = qiov;
+ acb->req.flags = flags;
+ acb->is_write = is_write;
+
+ co = qemu_coroutine_create(bdrv_co_do_rw);
+ qemu_coroutine_enter(co, acb);
+
+ bdrv_co_maybe_schedule_bh(acb);
+ return &acb->common;
+}
+
+static void coroutine_fn bdrv_aio_flush_co_entry(void *opaque)
+{
+ BlockAIOCBCoroutine *acb = opaque;
+ BlockDriverState *bs = acb->common.bs;
+
+ acb->req.error = bdrv_co_flush(bs);
+ bdrv_co_complete(acb);
+}
+
+BlockAIOCB *bdrv_aio_flush(BlockDriverState *bs,
+ BlockCompletionFunc *cb, void *opaque)
+{
+ trace_bdrv_aio_flush(bs, opaque);
+
+ Coroutine *co;
+ BlockAIOCBCoroutine *acb;
+
+ acb = qemu_aio_get(&bdrv_em_co_aiocb_info, bs, cb, opaque);
+ acb->need_bh = true;
+ acb->req.error = -EINPROGRESS;
+
+ co = qemu_coroutine_create(bdrv_aio_flush_co_entry);
+ qemu_coroutine_enter(co, acb);
+
+ bdrv_co_maybe_schedule_bh(acb);
+ return &acb->common;
+}
+
+static void coroutine_fn bdrv_aio_discard_co_entry(void *opaque)
+{
+ BlockAIOCBCoroutine *acb = opaque;
+ BlockDriverState *bs = acb->common.bs;
+
+ acb->req.error = bdrv_co_discard(bs, acb->req.sector, acb->req.nb_sectors);
+ bdrv_co_complete(acb);
+}
+
+BlockAIOCB *bdrv_aio_discard(BlockDriverState *bs,
+ int64_t sector_num, int nb_sectors,
+ BlockCompletionFunc *cb, void *opaque)
+{
+ Coroutine *co;
+ BlockAIOCBCoroutine *acb;
+
+ trace_bdrv_aio_discard(bs, sector_num, nb_sectors, opaque);
+
+ acb = qemu_aio_get(&bdrv_em_co_aiocb_info, bs, cb, opaque);
+ acb->need_bh = true;
+ acb->req.error = -EINPROGRESS;
+ acb->req.sector = sector_num;
+ acb->req.nb_sectors = nb_sectors;
+ co = qemu_coroutine_create(bdrv_aio_discard_co_entry);
+ qemu_coroutine_enter(co, acb);
+
+ bdrv_co_maybe_schedule_bh(acb);
+ return &acb->common;
+}
+
+void *qemu_aio_get(const AIOCBInfo *aiocb_info, BlockDriverState *bs,
+ BlockCompletionFunc *cb, void *opaque)
+{
+ BlockAIOCB *acb;
+
+ acb = g_slice_alloc(aiocb_info->aiocb_size);
+ acb->aiocb_info = aiocb_info;
+ acb->bs = bs;
+ acb->cb = cb;
+ acb->opaque = opaque;
+ acb->refcnt = 1;
+ return acb;
+}
+
+void qemu_aio_ref(void *p)
+{
+ BlockAIOCB *acb = p;
+ acb->refcnt++;
+}
+
+void qemu_aio_unref(void *p)
+{
+ BlockAIOCB *acb = p;
+ assert(acb->refcnt > 0);
+ if (--acb->refcnt == 0) {
+ g_slice_free1(acb->aiocb_info->aiocb_size, acb);
+ }
+}
+
+/**************************************************************/
+/* Coroutine block device emulation */
+
+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;
+ qemu_coroutine_enter(co->coroutine, NULL);
+}
+
+static int coroutine_fn bdrv_co_io_em(BlockDriverState *bs, int64_t sector_num,
+ int nb_sectors, QEMUIOVector *iov,
+ bool is_write)
+{
+ CoroutineIOCompletion co = {
+ .coroutine = qemu_coroutine_self(),
+ };
+ BlockAIOCB *acb;
+
+ if (is_write) {
+ acb = bs->drv->bdrv_aio_writev(bs, sector_num, iov, nb_sectors,
+ bdrv_co_io_em_complete, &co);
+ } else {
+ acb = bs->drv->bdrv_aio_readv(bs, sector_num, iov, nb_sectors,
+ bdrv_co_io_em_complete, &co);
+ }
+
+ trace_bdrv_co_io_em(bs, sector_num, nb_sectors, is_write, acb);
+ if (!acb) {
+ return -EIO;
+ }
+ qemu_coroutine_yield();
+
+ return co.ret;
+}
+
+static int coroutine_fn bdrv_co_readv_em(BlockDriverState *bs,
+ int64_t sector_num, int nb_sectors,
+ QEMUIOVector *iov)
+{
+ return bdrv_co_io_em(bs, sector_num, nb_sectors, iov, false);
+}
+
+static int coroutine_fn bdrv_co_writev_em(BlockDriverState *bs,
+ int64_t sector_num, int nb_sectors,
+ QEMUIOVector *iov)
+{
+ return bdrv_co_io_em(bs, sector_num, nb_sectors, iov, true);
+}
+
+static void coroutine_fn bdrv_flush_co_entry(void *opaque)
+{
+ RwCo *rwco = opaque;
+
+ rwco->ret = bdrv_co_flush(rwco->bs);
+}
+
+int coroutine_fn bdrv_co_flush(BlockDriverState *bs)
+{
+ int ret;
+
+ if (!bs || !bdrv_is_inserted(bs) || bdrv_is_read_only(bs) ||
+ bdrv_is_sg(bs)) {
+ return 0;
+ }
+
+ /* 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) {
+ return ret;
+ }
+ }
+
+ /* But don't actually force it to the disk with cache=unsafe */
+ if (bs->open_flags & BDRV_O_NO_FLUSH) {
+ 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) {
+ return ret;
+ }
+
+ /* 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:
+ return bdrv_co_flush(bs->file);
+}
+
+int bdrv_flush(BlockDriverState *bs)
+{
+ Coroutine *co;
+ RwCo rwco = {
+ .bs = bs,
+ .ret = NOT_DONE,
+ };
+
+ if (qemu_in_coroutine()) {
+ /* Fast-path if already in coroutine context */
+ bdrv_flush_co_entry(&rwco);
+ } else {
+ AioContext *aio_context = bdrv_get_aio_context(bs);
+
+ co = qemu_coroutine_create(bdrv_flush_co_entry);
+ qemu_coroutine_enter(co, &rwco);
+ while (rwco.ret == NOT_DONE) {
+ aio_poll(aio_context, true);
+ }
+ }
+
+ return rwco.ret;
+}
+
+typedef struct DiscardCo {
+ BlockDriverState *bs;
+ int64_t sector_num;
+ int nb_sectors;
+ int ret;
+} DiscardCo;
+static void coroutine_fn bdrv_discard_co_entry(void *opaque)
+{
+ DiscardCo *rwco = opaque;
+
+ rwco->ret = bdrv_co_discard(rwco->bs, rwco->sector_num, rwco->nb_sectors);
+}
+
+int coroutine_fn bdrv_co_discard(BlockDriverState *bs, int64_t sector_num,
+ int nb_sectors)
+{
+ int max_discard, ret;
+
+ if (!bs->drv) {
+ return -ENOMEDIUM;
+ }
+
+ ret = bdrv_check_request(bs, sector_num, nb_sectors);
+ if (ret < 0) {
+ return ret;
+ } else if (bs->read_only) {
+ return -EPERM;
+ }
+
+ /* Do nothing if disabled. */
+ if (!(bs->open_flags & BDRV_O_UNMAP)) {
+ return 0;
+ }
+
+ if (!bs->drv->bdrv_co_discard && !bs->drv->bdrv_aio_discard) {
+ return 0;
+ }
+
+ bdrv_set_dirty(bs, sector_num, nb_sectors);
+
+ max_discard = MIN_NON_ZERO(bs->bl.max_discard, BDRV_REQUEST_MAX_SECTORS);
+ while (nb_sectors > 0) {
+ int ret;
+ int num = nb_sectors;
+
+ /* align request */
+ if (bs->bl.discard_alignment &&
+ num >= bs->bl.discard_alignment &&
+ sector_num % bs->bl.discard_alignment) {
+ if (num > bs->bl.discard_alignment) {
+ num = bs->bl.discard_alignment;
+ }
+ num -= sector_num % bs->bl.discard_alignment;
+ }
+
+ /* limit request size */
+ if (num > max_discard) {
+ num = max_discard;
+ }
+
+ if (bs->drv->bdrv_co_discard) {
+ ret = bs->drv->bdrv_co_discard(bs, sector_num, num);
+ } else {
+ BlockAIOCB *acb;
+ CoroutineIOCompletion co = {
+ .coroutine = qemu_coroutine_self(),
+ };
+
+ acb = bs->drv->bdrv_aio_discard(bs, sector_num, nb_sectors,
+ bdrv_co_io_em_complete, &co);
+ if (acb == NULL) {
+ return -EIO;
+ } else {
+ qemu_coroutine_yield();
+ ret = co.ret;
+ }
+ }
+ if (ret && ret != -ENOTSUP) {
+ return ret;
+ }
+
+ sector_num += num;
+ nb_sectors -= num;
+ }
+ return 0;
+}
+
+int bdrv_discard(BlockDriverState *bs, int64_t sector_num, int nb_sectors)
+{
+ Coroutine *co;
+ DiscardCo rwco = {
+ .bs = bs,
+ .sector_num = sector_num,
+ .nb_sectors = nb_sectors,
+ .ret = NOT_DONE,
+ };
+
+ if (qemu_in_coroutine()) {
+ /* Fast-path if already in coroutine context */
+ bdrv_discard_co_entry(&rwco);
+ } else {
+ AioContext *aio_context = bdrv_get_aio_context(bs);
+
+ co = qemu_coroutine_create(bdrv_discard_co_entry);
+ qemu_coroutine_enter(co, &rwco);
+ while (rwco.ret == NOT_DONE) {
+ aio_poll(aio_context, true);
+ }
+ }
+
+ return rwco.ret;
+}
+
+/* needed for generic scsi interface */
+
+int bdrv_ioctl(BlockDriverState *bs, unsigned long int req, void *buf)
+{
+ BlockDriver *drv = bs->drv;
+
+ if (drv && drv->bdrv_ioctl)
+ return drv->bdrv_ioctl(bs, req, buf);
+ return -ENOTSUP;
+}
+
+BlockAIOCB *bdrv_aio_ioctl(BlockDriverState *bs,
+ unsigned long int req, void *buf,
+ BlockCompletionFunc *cb, void *opaque)
+{
+ BlockDriver *drv = bs->drv;
+
+ if (drv && drv->bdrv_aio_ioctl)
+ return drv->bdrv_aio_ioctl(bs, req, buf, cb, opaque);
+ return NULL;
+}
+
+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)
+{
+ BlockDriver *drv = bs->drv;
+ if (drv && drv->bdrv_io_plug) {
+ drv->bdrv_io_plug(bs);
+ } else if (bs->file) {
+ bdrv_io_plug(bs->file);
+ }
+}
+
+void bdrv_io_unplug(BlockDriverState *bs)
+{
+ BlockDriver *drv = bs->drv;
+ if (drv && drv->bdrv_io_unplug) {
+ drv->bdrv_io_unplug(bs);
+ } else if (bs->file) {
+ bdrv_io_unplug(bs->file);
+ }
+}
+
+void bdrv_flush_io_queue(BlockDriverState *bs)
+{
+ BlockDriver *drv = bs->drv;
+ if (drv && drv->bdrv_flush_io_queue) {
+ drv->bdrv_flush_io_queue(bs);
+ } else if (bs->file) {
+ bdrv_flush_io_queue(bs->file);
+ }
+ bdrv_start_throttled_reqs(bs);
+}
Code Review / kvmfornfv.git / blobdiff