From 61b49e48b379db45f0ea91c93a61c873695549a9 Mon Sep 17 00:00:00 2001 From: Alberto Garcia Date: Fri, 28 Oct 2016 10:08:10 +0300 Subject: [PATCH] block: Support streaming to an intermediate layer This makes sure that the image we are streaming into is open in read-write mode during the operation. Operation blockers are also set in all intermediate nodes, since they will be removed from the chain afterwards. Finally, this also unblocks the stream operation in backing files. Signed-off-by: Alberto Garcia Reviewed-by: Kevin Wolf Signed-off-by: Kevin Wolf --- block.c | 4 +++- block/stream.c | 24 ++++++++++++++++++++++++ 2 files changed, 27 insertions(+), 1 deletion(-) diff --git a/block.c b/block.c index 2c87186ecf..c19c6c6d42 100644 --- a/block.c +++ b/block.c @@ -1428,9 +1428,11 @@ void bdrv_set_backing_hd(BlockDriverState *bs, BlockDriverState *backing_hd) backing_hd->drv ? backing_hd->drv->format_name : ""); bdrv_op_block_all(backing_hd, bs->backing_blocker); - /* Otherwise we won't be able to commit due to check in bdrv_commit */ + /* Otherwise we won't be able to commit or stream */ bdrv_op_unblock(backing_hd, BLOCK_OP_TYPE_COMMIT_TARGET, bs->backing_blocker); + bdrv_op_unblock(backing_hd, BLOCK_OP_TYPE_STREAM, + bs->backing_blocker); /* * We do backup in 3 ways: * 1. drive backup diff --git a/block/stream.c b/block/stream.c index 31874817c2..b8ab89a105 100644 --- a/block/stream.c +++ b/block/stream.c @@ -37,6 +37,7 @@ typedef struct StreamBlockJob { BlockDriverState *base; BlockdevOnError on_error; char *backing_file_str; + int bs_flags; } StreamBlockJob; static int coroutine_fn stream_populate(BlockBackend *blk, @@ -81,6 +82,11 @@ static void stream_complete(BlockJob *job, void *opaque) bdrv_set_backing_hd(bs, base); } + /* Reopen the image back in read-only mode if necessary */ + if (s->bs_flags != bdrv_get_flags(bs)) { + bdrv_reopen(bs, s->bs_flags, NULL); + } + g_free(s->backing_file_str); block_job_completed(&s->common, data->ret); g_free(data); @@ -220,6 +226,8 @@ void stream_start(const char *job_id, BlockDriverState *bs, BlockCompletionFunc *cb, void *opaque, Error **errp) { StreamBlockJob *s; + BlockDriverState *iter; + int orig_bs_flags; s = block_job_create(job_id, &stream_job_driver, bs, speed, cb, opaque, errp); @@ -227,8 +235,24 @@ void stream_start(const char *job_id, BlockDriverState *bs, return; } + /* Make sure that the image is opened in read-write mode */ + orig_bs_flags = bdrv_get_flags(bs); + if (!(orig_bs_flags & BDRV_O_RDWR)) { + if (bdrv_reopen(bs, orig_bs_flags | BDRV_O_RDWR, errp) != 0) { + block_job_unref(&s->common); + return; + } + } + + /* Block all intermediate nodes between bs and base, because they + * will disappear from the chain after this operation */ + for (iter = backing_bs(bs); iter && iter != base; iter = backing_bs(iter)) { + block_job_add_bdrv(&s->common, iter); + } + s->base = base; s->backing_file_str = g_strdup(backing_file_str); + s->bs_flags = orig_bs_flags; s->on_error = on_error; s->common.co = qemu_coroutine_create(stream_run, s); -- 2.30.2