| /* |
| * 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 "qemu/osdep.h" |
| #include "trace.h" |
| #include "sysemu/block-backend.h" |
| #include "block/blockjob.h" |
| #include "block/block_int.h" |
| #include "qemu/cutils.h" |
| #include "qapi/error.h" |
| #include "qemu/error-report.h" |
| |
| #define NOT_DONE 0x7fffffff /* used while emulated sync operation in progress */ |
| |
| static BlockAIOCB *bdrv_co_aio_prw_vector(BdrvChild *child, |
| int64_t offset, |
| QEMUIOVector *qiov, |
| 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_pwrite_zeroes(BlockDriverState *bs, |
| int64_t offset, int count, BdrvRequestFlags flags); |
| |
| void bdrv_parent_drained_begin(BlockDriverState *bs) |
| { |
| BdrvChild *c; |
| |
| QLIST_FOREACH(c, &bs->parents, next_parent) { |
| if (c->role->drained_begin) { |
| c->role->drained_begin(c); |
| } |
| } |
| } |
| |
| void bdrv_parent_drained_end(BlockDriverState *bs) |
| { |
| BdrvChild *c; |
| |
| QLIST_FOREACH(c, &bs->parents, next_parent) { |
| if (c->role->drained_end) { |
| c->role->drained_end(c); |
| } |
| } |
| } |
| |
| static void bdrv_merge_limits(BlockLimits *dst, const BlockLimits *src) |
| { |
| dst->opt_transfer = MAX(dst->opt_transfer, src->opt_transfer); |
| dst->max_transfer = MIN_NON_ZERO(dst->max_transfer, src->max_transfer); |
| dst->opt_mem_alignment = MAX(dst->opt_mem_alignment, |
| src->opt_mem_alignment); |
| dst->min_mem_alignment = MAX(dst->min_mem_alignment, |
| src->min_mem_alignment); |
| dst->max_iov = MIN_NON_ZERO(dst->max_iov, src->max_iov); |
| } |
| |
| 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; |
| } |
| |
| /* Default alignment based on whether driver has byte interface */ |
| bs->bl.request_alignment = drv->bdrv_co_preadv ? 1 : 512; |
| |
| /* Take some limits from the children as a default */ |
| if (bs->file) { |
| bdrv_refresh_limits(bs->file->bs, &local_err); |
| if (local_err) { |
| error_propagate(errp, local_err); |
| return; |
| } |
| bdrv_merge_limits(&bs->bl, &bs->file->bs->bl); |
| } else { |
| bs->bl.min_mem_alignment = 512; |
| bs->bl.opt_mem_alignment = getpagesize(); |
| |
| /* Safe default since most protocols use readv()/writev()/etc */ |
| bs->bl.max_iov = IOV_MAX; |
| } |
| |
| if (bs->backing) { |
| bdrv_refresh_limits(bs->backing->bs, &local_err); |
| if (local_err) { |
| error_propagate(errp, local_err); |
| return; |
| } |
| bdrv_merge_limits(&bs->bl, &bs->backing->bs->bl); |
| } |
| |
| /* 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) */ |
| bool bdrv_requests_pending(BlockDriverState *bs) |
| { |
| BdrvChild *child; |
| |
| if (atomic_read(&bs->in_flight)) { |
| return true; |
| } |
| |
| QLIST_FOREACH(child, &bs->children, next) { |
| if (bdrv_requests_pending(child->bs)) { |
| return true; |
| } |
| } |
| |
| return false; |
| } |
| |
| static bool bdrv_drain_recurse(BlockDriverState *bs) |
| { |
| BdrvChild *child, *tmp; |
| bool waited; |
| |
| waited = BDRV_POLL_WHILE(bs, atomic_read(&bs->in_flight) > 0); |
| |
| if (bs->drv && bs->drv->bdrv_drain) { |
| bs->drv->bdrv_drain(bs); |
| } |
| |
| QLIST_FOREACH_SAFE(child, &bs->children, next, tmp) { |
| BlockDriverState *bs = child->bs; |
| bool in_main_loop = |
| qemu_get_current_aio_context() == qemu_get_aio_context(); |
| assert(bs->refcnt > 0); |
| if (in_main_loop) { |
| /* In case the recursive bdrv_drain_recurse processes a |
| * block_job_defer_to_main_loop BH and modifies the graph, |
| * let's hold a reference to bs until we are done. |
| * |
| * IOThread doesn't have such a BH, and it is not safe to call |
| * bdrv_unref without BQL, so skip doing it there. |
| */ |
| bdrv_ref(bs); |
| } |
| waited |= bdrv_drain_recurse(bs); |
| if (in_main_loop) { |
| bdrv_unref(bs); |
| } |
| } |
| |
| return waited; |
| } |
| |
| typedef struct { |
| Coroutine *co; |
| BlockDriverState *bs; |
| bool done; |
| } BdrvCoDrainData; |
| |
| static void bdrv_co_drain_bh_cb(void *opaque) |
| { |
| BdrvCoDrainData *data = opaque; |
| Coroutine *co = data->co; |
| BlockDriverState *bs = data->bs; |
| |
| bdrv_dec_in_flight(bs); |
| bdrv_drained_begin(bs); |
| data->done = true; |
| aio_co_wake(co); |
| } |
| |
| static void coroutine_fn bdrv_co_yield_to_drain(BlockDriverState *bs) |
| { |
| BdrvCoDrainData data; |
| |
| /* Calling bdrv_drain() from a BH ensures the current coroutine yields and |
| * other coroutines run if they were queued from |
| * qemu_co_queue_run_restart(). */ |
| |
| assert(qemu_in_coroutine()); |
| data = (BdrvCoDrainData) { |
| .co = qemu_coroutine_self(), |
| .bs = bs, |
| .done = false, |
| }; |
| bdrv_inc_in_flight(bs); |
| aio_bh_schedule_oneshot(bdrv_get_aio_context(bs), |
| bdrv_co_drain_bh_cb, &data); |
| |
| qemu_coroutine_yield(); |
| /* If we are resumed from some other event (such as an aio completion or a |
| * timer callback), it is a bug in the caller that should be fixed. */ |
| assert(data.done); |
| } |
| |
| void bdrv_drained_begin(BlockDriverState *bs) |
| { |
| if (qemu_in_coroutine()) { |
| bdrv_co_yield_to_drain(bs); |
| return; |
| } |
| |
| if (!bs->quiesce_counter++) { |
| aio_disable_external(bdrv_get_aio_context(bs)); |
| bdrv_parent_drained_begin(bs); |
| } |
| |
| bdrv_drain_recurse(bs); |
| } |
| |
| void bdrv_drained_end(BlockDriverState *bs) |
| { |
| assert(bs->quiesce_counter > 0); |
| if (--bs->quiesce_counter > 0) { |
| return; |
| } |
| |
| bdrv_parent_drained_end(bs); |
| aio_enable_external(bdrv_get_aio_context(bs)); |
| } |
| |
| /* |
| * Wait for pending requests to complete on a single BlockDriverState subtree, |
| * and suspend block driver's internal I/O until next request arrives. |
| * |
| * Note that unlike bdrv_drain_all(), the caller must hold the BlockDriverState |
| * AioContext. |
| * |
| * 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 coroutine_fn bdrv_co_drain(BlockDriverState *bs) |
| { |
| assert(qemu_in_coroutine()); |
| bdrv_drained_begin(bs); |
| bdrv_drained_end(bs); |
| } |
| |
| void bdrv_drain(BlockDriverState *bs) |
| { |
| bdrv_drained_begin(bs); |
| bdrv_drained_end(bs); |
| } |
| |
| /* |
| * Wait for pending requests to complete across all BlockDriverStates |
| * |
| * This function does not flush data to disk, use bdrv_flush_all() for that |
| * after calling this function. |
| * |
| * This pauses all block jobs and disables external clients. It must |
| * be paired with bdrv_drain_all_end(). |
| * |
| * NOTE: no new block jobs or BlockDriverStates can be created between |
| * the bdrv_drain_all_begin() and bdrv_drain_all_end() calls. |
| */ |
| void bdrv_drain_all_begin(void) |
| { |
| /* Always run first iteration so any pending completion BHs run */ |
| bool waited = true; |
| BlockDriverState *bs; |
| BdrvNextIterator it; |
| BlockJob *job = NULL; |
| GSList *aio_ctxs = NULL, *ctx; |
| |
| while ((job = block_job_next(job))) { |
| AioContext *aio_context = blk_get_aio_context(job->blk); |
| |
| aio_context_acquire(aio_context); |
| block_job_pause(job); |
| aio_context_release(aio_context); |
| } |
| |
| for (bs = bdrv_first(&it); bs; bs = bdrv_next(&it)) { |
| AioContext *aio_context = bdrv_get_aio_context(bs); |
| |
| aio_context_acquire(aio_context); |
| bdrv_parent_drained_begin(bs); |
| aio_disable_external(aio_context); |
| 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 (waited) { |
| waited = false; |
| |
| for (ctx = aio_ctxs; ctx != NULL; ctx = ctx->next) { |
| AioContext *aio_context = ctx->data; |
| |
| aio_context_acquire(aio_context); |
| for (bs = bdrv_first(&it); bs; bs = bdrv_next(&it)) { |
| if (aio_context == bdrv_get_aio_context(bs)) { |
| waited |= bdrv_drain_recurse(bs); |
| } |
| } |
| aio_context_release(aio_context); |
| } |
| } |
| |
| g_slist_free(aio_ctxs); |
| } |
| |
| void bdrv_drain_all_end(void) |
| { |
| BlockDriverState *bs; |
| BdrvNextIterator it; |
| BlockJob *job = NULL; |
| |
| for (bs = bdrv_first(&it); bs; bs = bdrv_next(&it)) { |
| AioContext *aio_context = bdrv_get_aio_context(bs); |
| |
| aio_context_acquire(aio_context); |
| aio_enable_external(aio_context); |
| bdrv_parent_drained_end(bs); |
| aio_context_release(aio_context); |
| } |
| |
| while ((job = block_job_next(job))) { |
| AioContext *aio_context = blk_get_aio_context(job->blk); |
| |
| aio_context_acquire(aio_context); |
| block_job_resume(job); |
| aio_context_release(aio_context); |
| } |
| } |
| |
| void bdrv_drain_all(void) |
| { |
| bdrv_drain_all_begin(); |
| bdrv_drain_all_end(); |
| } |
| |
| /** |
| * Remove an active request from the tracked requests list |
| * |
| * This function should be called when a tracked request is completing. |
| */ |
| static void tracked_request_end(BdrvTrackedRequest *req) |
| { |
| if (req->serialising) { |
| 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, |
| enum BdrvTrackedRequestType type) |
| { |
| *req = (BdrvTrackedRequest){ |
| .bs = bs, |
| .offset = offset, |
| .bytes = bytes, |
| .type = type, |
| .co = qemu_coroutine_self(), |
| .serialising = false, |
| .overlap_offset = offset, |
| .overlap_bytes = bytes, |
| }; |
| |
| qemu_co_queue_init(&req->wait_queue); |
| |
| 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 (sector-based) |
| */ |
| void bdrv_round_sectors_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); |
| } |
| } |
| |
| /** |
| * Round a region to cluster boundaries |
| */ |
| void bdrv_round_to_clusters(BlockDriverState *bs, |
| int64_t offset, unsigned int bytes, |
| int64_t *cluster_offset, |
| unsigned int *cluster_bytes) |
| { |
| BlockDriverInfo bdi; |
| |
| if (bdrv_get_info(bs, &bdi) < 0 || bdi.cluster_size == 0) { |
| *cluster_offset = offset; |
| *cluster_bytes = bytes; |
| } else { |
| int64_t c = bdi.cluster_size; |
| *cluster_offset = QEMU_ALIGN_DOWN(offset, c); |
| *cluster_bytes = QEMU_ALIGN_UP(offset - *cluster_offset + bytes, c); |
| } |
| } |
| |
| static int bdrv_get_cluster_size(BlockDriverState *bs) |
| { |
| BlockDriverInfo bdi; |
| int ret; |
| |
| ret = bdrv_get_info(bs, &bdi); |
| if (ret < 0 || bdi.cluster_size == 0) { |
| return bs->bl.request_alignment; |
| } else { |
| return bdi.cluster_size; |
| } |
| } |
| |
| 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) |
| { |
| if (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 (!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, NULL); |
| 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; |
| } |
| |
| 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 count, BdrvRequestFlags flags) |
| { |
| QEMUIOVector qiov; |
| struct iovec iov = { |
| .iov_base = NULL, |
| .iov_len = count, |
| }; |
| |
| 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) { |
| int64_t start_sector = offset >> BDRV_SECTOR_BITS; |
| int64_t end_sector = DIV_ROUND_UP(offset + bytes, BDRV_SECTOR_SIZE); |
| unsigned int nb_sectors = end_sector - start_sector; |
| int pnum; |
| |
| ret = bdrv_is_allocated(bs, start_sector, nb_sectors, &pnum); |
| if (ret < 0) { |
| goto out; |
| } |
| |
| if (!ret || pnum != nb_sectors) { |
| 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 (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 count, 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 + count) % alignment; |
| max_write_zeroes = QEMU_ALIGN_DOWN(max_write_zeroes, alignment); |
| assert(max_write_zeroes >= bs->bl.request_alignment); |
| |
| while (count > 0 && !ret) { |
| int num = count; |
| |
| /* 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(count, 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; |
| count -= 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; |
| |
| 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); |
| |
| ++bs->write_gen; |
| bdrv_set_dirty(bs, start_sector, end_sector - start_sector); |
| |
| if (bs->wr_highest_offset < offset + bytes) { |
| 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 count, BdrvRequestFlags flags) |
| { |
| trace_bdrv_co_pwrite_zeroes(child->bs, offset, count, flags); |
| |
| if (!(child->bs->open_flags & BDRV_O_UNMAP)) { |
| flags &= ~BDRV_REQ_MAY_UNMAP; |
| } |
| |
| return bdrv_co_pwritev(child, offset, count, 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 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. |
| * |
| * 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; |
| |
| 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; |
| } |
| |
| *file = NULL; |
| 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); |
| ret = bdrv_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 (!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); |
| } |
| } |
| } |
| |
| out: |
| bdrv_dec_in_flight(bs); |
| 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; |
| |
| 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 || 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->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 sector_num, |
| int nb_sectors, int *pnum) |
| { |
| BlockDriverState *file; |
| int64_t ret = bdrv_get_block_status(bs, sector_num, nb_sectors, pnum, |
| &file); |
| 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 = 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; |
| |
| if (!drv) { |
| return -ENOMEDIUM; |
| } else if (drv->bdrv_load_vmstate) { |
| return is_read ? drv->bdrv_load_vmstate(bs, qiov, pos) |
| : drv->bdrv_save_vmstate(bs, qiov, pos); |
| } else if (bs->file) { |
| return bdrv_co_rw_vmstate(bs->file->bs, qiov, pos, is_read); |
| } |
| |
| return -ENOTSUP; |
| } |
| |
| 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); |
| while (data.ret == -EINPROGRESS) { |
| aio_poll(bdrv_get_aio_context(bs), true); |
| } |
| 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 */ |
| |
| BlockAIOCB *bdrv_aio_readv(BdrvChild *child, int64_t sector_num, |
| QEMUIOVector *qiov, int nb_sectors, |
| BlockCompletionFunc *cb, void *opaque) |
| { |
| trace_bdrv_aio_readv(child->bs, sector_num, nb_sectors, opaque); |
| |
| assert(nb_sectors << BDRV_SECTOR_BITS == qiov->size); |
| return bdrv_co_aio_prw_vector(child, sector_num << BDRV_SECTOR_BITS, qiov, |
| 0, cb, opaque, false); |
| } |
| |
| BlockAIOCB *bdrv_aio_writev(BdrvChild *child, int64_t sector_num, |
| QEMUIOVector *qiov, int nb_sectors, |
| BlockCompletionFunc *cb, void *opaque) |
| { |
| trace_bdrv_aio_writev(child->bs, sector_num, nb_sectors, opaque); |
| |
| assert(nb_sectors << BDRV_SECTOR_BITS == qiov->size); |
| return bdrv_co_aio_prw_vector(child, sector_num << BDRV_SECTOR_BITS, qiov, |
| 0, cb, opaque, true); |
| } |
| |
| 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); |
| } |
| } |
| |
| /**************************************************************/ |
| /* async block device emulation */ |
| |
| typedef struct BlockRequest { |
| union { |
| /* Used during read, write, trim */ |
| struct { |
| int64_t offset; |
| int bytes; |
| int flags; |
| QEMUIOVector *qiov; |
| }; |
| /* Used during ioctl */ |
| struct { |
| int req; |
| void *buf; |
| }; |
| }; |
| BlockCompletionFunc *cb; |
| void *opaque; |
| |
| int error; |
| } BlockRequest; |
| |
| typedef struct BlockAIOCBCoroutine { |
| BlockAIOCB common; |
| BdrvChild *child; |
| BlockRequest req; |
| bool is_write; |
| bool need_bh; |
| bool *done; |
| } BlockAIOCBCoroutine; |
| |
| static const AIOCBInfo bdrv_em_co_aiocb_info = { |
| .aiocb_size = sizeof(BlockAIOCBCoroutine), |
| }; |
| |
| static void bdrv_co_complete(BlockAIOCBCoroutine *acb) |
| { |
| if (!acb->need_bh) { |
| bdrv_dec_in_flight(acb->common.bs); |
| 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); |
| 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; |
| |
| aio_bh_schedule_oneshot(bdrv_get_aio_context(bs), bdrv_co_em_bh, acb); |
| } |
| } |
| |
| /* Invoke bdrv_co_do_readv/bdrv_co_do_writev */ |
| static void coroutine_fn bdrv_co_do_rw(void *opaque) |
| { |
| BlockAIOCBCoroutine *acb = opaque; |
| |
| if (!acb->is_write) { |
| acb->req.error = bdrv_co_preadv(acb->child, acb->req.offset, |
| acb->req.qiov->size, acb->req.qiov, acb->req.flags); |
| } else { |
| acb->req.error = bdrv_co_pwritev(acb->child, acb->req.offset, |
| acb->req.qiov->size, acb->req.qiov, acb->req.flags); |
| } |
| |
| bdrv_co_complete(acb); |
| } |
| |
| static BlockAIOCB *bdrv_co_aio_prw_vector(BdrvChild *child, |
| int64_t offset, |
| QEMUIOVector *qiov, |
| BdrvRequestFlags flags, |
| BlockCompletionFunc *cb, |
| void *opaque, |
| bool is_write) |
| { |
| Coroutine *co; |
| BlockAIOCBCoroutine *acb; |
| |
| /* Matched by bdrv_co_complete's bdrv_dec_in_flight. */ |
| bdrv_inc_in_flight(child->bs); |
| |
| acb = qemu_aio_get(&bdrv_em_co_aiocb_info, child->bs, cb, opaque); |
| acb->child = child; |
| acb->need_bh = true; |
| acb->req.error = -EINPROGRESS; |
| acb->req.offset = offset; |
| acb->req.qiov = qiov; |
| acb->req.flags = flags; |
| acb->is_write = is_write; |
| |
| co = qemu_coroutine_create(bdrv_co_do_rw, acb); |
| bdrv_coroutine_enter(child->bs, co); |
| |
| 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; |
| |
| /* Matched by bdrv_co_complete's bdrv_dec_in_flight. */ |
| bdrv_inc_in_flight(bs); |
| |
| 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, acb); |
| bdrv_coroutine_enter(bs, co); |
| |
| bdrv_co_maybe_schedule_bh(acb); |
| return &acb->common; |
| } |
| |
| /**************************************************************/ |
| /* 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; |
| } |
| |
| current_gen = bs->write_gen; |
| |
| /* Wait until any previous flushes are completed */ |
| while (bs->active_flush_req) { |
| qemu_co_queue_wait(&bs->flush_queue, NULL); |
| } |
| |
| bs->active_flush_req = true; |
| |
| /* 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; |
| } |
| bs->active_flush_req = false; |
| /* Return value is ignored - it's ok if wait queue is empty */ |
| qemu_co_queue_next(&bs->flush_queue); |
| |
| 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 count; |
| 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->count); |
| } |
| |
| int coroutine_fn bdrv_co_pdiscard(BlockDriverState *bs, int64_t offset, |
| int count) |
| { |
| BdrvTrackedRequest req; |
| int max_pdiscard, ret; |
| int head, tail, align; |
| |
| if (!bs->drv) { |
| return -ENOMEDIUM; |
| } |
| |
| ret = bdrv_check_byte_request(bs, offset, count); |
| 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 + count) % align; |
| |
| bdrv_inc_in_flight(bs); |
| tracked_request_begin(&req, bs, offset, count, 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 (count > 0) { |
| int ret; |
| int num = count; |
| |
| if (head) { |
| /* Make small requests to get to alignment boundaries. */ |
| num = MIN(count, 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; |
| count -= num; |
| } |
| ret = 0; |
| out: |
| ++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 count) |
| { |
| Coroutine *co; |
| DiscardCo rwco = { |
| .bs = bs, |
| .offset = offset, |
| .count = count, |
| .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 (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 (--bs->io_plugged == 0) { |
| 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); |
| } |
| } |