Add a CoMutex to protect concurrent access of block-copy data structures. This mutex also protects .copy_bitmap, because its thread-safe API does not prevent it from assigning two tasks to the same bitmap region.
.finished, .cancelled and reads to .ret and .error_is_read will be protected in the following patch, because are used also outside coroutines. Also set block_copy_task_create as coroutine_fn because: 1) it is static and only invoked by coroutine functions 2) this patch introduces and uses a CoMutex lock there Signed-off-by: Emanuele Giuseppe Esposito <eespo...@redhat.com> --- block/block-copy.c | 82 ++++++++++++++++++++++++++++++---------------- 1 file changed, 54 insertions(+), 28 deletions(-) diff --git a/block/block-copy.c b/block/block-copy.c index e2adb5b2ea..56f62913e4 100644 --- a/block/block-copy.c +++ b/block/block-copy.c @@ -61,6 +61,7 @@ typedef struct BlockCopyCallState { /* OUT parameters */ bool cancelled; + /* Fields protected by lock in BlockCopyState */ bool error_is_read; int ret; } BlockCopyCallState; @@ -78,7 +79,7 @@ typedef struct BlockCopyTask { int64_t bytes; /* only re-set in task_shrink, before running the task */ BlockCopyMethod method; /* initialized in block_copy_dirty_clusters() */ - /* State */ + /* State. Protected by lock in BlockCopyState */ CoQueue wait_queue; /* coroutines blocked on this task */ /* To reference all call states from BlockCopyState */ @@ -99,7 +100,8 @@ typedef struct BlockCopyState { BdrvChild *source; BdrvChild *target; - /* State */ + /* State. Protected by lock */ + CoMutex lock; int64_t in_flight_bytes; BlockCopyMethod method; QLIST_HEAD(, BlockCopyTask) tasks; /* All tasks from all block-copy calls */ @@ -139,8 +141,10 @@ typedef struct BlockCopyState { bool skip_unallocated; } BlockCopyState; -static BlockCopyTask *find_conflicting_task(BlockCopyState *s, - int64_t offset, int64_t bytes) +/* Called with lock held */ +static BlockCopyTask *find_conflicting_task_locked(BlockCopyState *s, + int64_t offset, + int64_t bytes) { BlockCopyTask *t; @@ -160,18 +164,22 @@ static BlockCopyTask *find_conflicting_task(BlockCopyState *s, static bool coroutine_fn block_copy_wait_one(BlockCopyState *s, int64_t offset, int64_t bytes) { - BlockCopyTask *task = find_conflicting_task(s, offset, bytes); + BlockCopyTask *task; + + QEMU_LOCK_GUARD(&s->lock); + task = find_conflicting_task_locked(s, offset, bytes); if (!task) { return false; } - qemu_co_queue_wait(&task->wait_queue, NULL); + qemu_co_queue_wait(&task->wait_queue, &s->lock); return true; } -static int64_t block_copy_chunk_size(BlockCopyState *s) +/* Called with lock held */ +static int64_t block_copy_chunk_size_locked(BlockCopyState *s) { switch (s->method) { case COPY_READ_WRITE_CLUSTER: @@ -193,14 +201,16 @@ static int64_t block_copy_chunk_size(BlockCopyState *s) * Search for the first dirty area in offset/bytes range and create task at * the beginning of it. */ -static BlockCopyTask *block_copy_task_create(BlockCopyState *s, - BlockCopyCallState *call_state, - int64_t offset, int64_t bytes) +static coroutine_fn BlockCopyTask *block_copy_task_create(BlockCopyState *s, + BlockCopyCallState *call_state, + int64_t offset, int64_t bytes) { BlockCopyTask *task; - int64_t max_chunk = block_copy_chunk_size(s); + int64_t max_chunk; - max_chunk = MIN_NON_ZERO(max_chunk, call_state->max_chunk); + QEMU_LOCK_GUARD(&s->lock); + max_chunk = MIN_NON_ZERO(block_copy_chunk_size_locked(s), + call_state->max_chunk); if (!bdrv_dirty_bitmap_next_dirty_area(s->copy_bitmap, offset, offset + bytes, max_chunk, &offset, &bytes)) @@ -212,7 +222,7 @@ static BlockCopyTask *block_copy_task_create(BlockCopyState *s, bytes = QEMU_ALIGN_UP(bytes, s->cluster_size); /* region is dirty, so no existent tasks possible in it */ - assert(!find_conflicting_task(s, offset, bytes)); + assert(!find_conflicting_task_locked(s, offset, bytes)); bdrv_reset_dirty_bitmap(s->copy_bitmap, offset, bytes); s->in_flight_bytes += bytes; @@ -248,16 +258,19 @@ static void coroutine_fn block_copy_task_shrink(BlockCopyTask *task, assert(new_bytes > 0 && new_bytes < task->bytes); - task->s->in_flight_bytes -= task->bytes - new_bytes; - bdrv_set_dirty_bitmap(task->s->copy_bitmap, - task->offset + new_bytes, task->bytes - new_bytes); - - task->bytes = new_bytes; - qemu_co_queue_restart_all(&task->wait_queue); + WITH_QEMU_LOCK_GUARD(&task->s->lock) { + task->s->in_flight_bytes -= task->bytes - new_bytes; + bdrv_set_dirty_bitmap(task->s->copy_bitmap, + task->offset + new_bytes, + task->bytes - new_bytes); + task->bytes = new_bytes; + qemu_co_queue_restart_all(&task->wait_queue); + } } static void coroutine_fn block_copy_task_end(BlockCopyTask *task, int ret) { + QEMU_LOCK_GUARD(&task->s->lock); task->s->in_flight_bytes -= task->bytes; if (ret < 0) { bdrv_set_dirty_bitmap(task->s->copy_bitmap, task->offset, task->bytes); @@ -335,6 +348,7 @@ BlockCopyState *block_copy_state_new(BdrvChild *source, BdrvChild *target, } ratelimit_init(&s->rate_limit); + qemu_co_mutex_init(&s->lock); QLIST_INIT(&s->tasks); QLIST_INIT(&s->calls); @@ -390,6 +404,8 @@ static coroutine_fn int block_copy_task_run(AioTaskPool *pool, * a full-size buffer or disabled if the copy_range attempt fails. The output * value of @method should be used for subsequent tasks. * Returns 0 on success. + * + * Called with lock held. */ static int coroutine_fn block_copy_do_copy(BlockCopyState *s, int64_t offset, int64_t bytes, @@ -476,16 +492,20 @@ static coroutine_fn int block_copy_task_entry(AioTask *task) int ret; ret = block_copy_do_copy(s, t->offset, t->bytes, &method, &error_is_read); - if (s->method == t->method) { - s->method = method; - } - if (ret < 0) { - if (!t->call_state->ret) { - t->call_state->ret = ret; - t->call_state->error_is_read = error_is_read; + + WITH_QEMU_LOCK_GUARD(&t->s->lock) { + if (s->method == t->method) { + s->method = method; + } + + if (ret < 0) { + if (!t->call_state->ret) { + t->call_state->ret = ret; + t->call_state->error_is_read = error_is_read; + } + } else { + progress_work_done(t->s->progress, t->bytes); } - } else { - progress_work_done(t->s->progress, t->bytes); } co_put_to_shres(t->s->mem, t->bytes); block_copy_task_end(t, ret); @@ -587,10 +607,12 @@ int64_t block_copy_reset_unallocated(BlockCopyState *s, bytes = clusters * s->cluster_size; if (!ret) { + qemu_co_mutex_lock(&s->lock); bdrv_reset_dirty_bitmap(s->copy_bitmap, offset, bytes); progress_set_remaining(s->progress, bdrv_get_dirty_count(s->copy_bitmap) + s->in_flight_bytes); + qemu_co_mutex_unlock(&s->lock); } *count = bytes; @@ -729,7 +751,9 @@ static int coroutine_fn block_copy_common(BlockCopyCallState *call_state) { int ret; + qemu_co_mutex_lock(&call_state->s->lock); QLIST_INSERT_HEAD(&call_state->s->calls, call_state, list); + qemu_co_mutex_unlock(&call_state->s->lock); do { ret = block_copy_dirty_clusters(call_state); @@ -756,7 +780,9 @@ static int coroutine_fn block_copy_common(BlockCopyCallState *call_state) call_state->cb(call_state->cb_opaque); } + qemu_co_mutex_lock(&call_state->s->lock); QLIST_REMOVE(call_state, list); + qemu_co_mutex_unlock(&call_state->s->lock); return ret; } -- 2.30.2