[PATCH v3 4/5] block-stream: add compress option

[Andrey Shinkevich <andrey.shinkevich@virtuozzo.com>]

Allow data compression during block-stream job for backup backing chain.

Signed-off-by: Andrey Shinkevich <andrey.shinkevich@virtuozzo.com>
---
 block/stream.c | 10 ++++++++--
 blockdev.c     | 12 +++++++++++-
 2 files changed, 19 insertions(+), 3 deletions(-)

diff --git a/block/stream.c b/block/stream.c
index 5562ccb..25f9324 100644
--- a/block/stream.c
+++ b/block/stream.c
@@ -41,10 +41,16 @@ typedef struct StreamBlockJob {
 static int coroutine_fn stream_populate(BlockBackend *blk,
                                         int64_t offset, uint64_t bytes)
 {
+    BlockDriverState *bs = blk_bs(blk);
+    int flags = BDRV_REQ_COPY_ON_READ | BDRV_REQ_PREFETCH;
+
+    if (bs->all_write_compressed) {
+        flags |= BDRV_REQ_WRITE_COMPRESSED;
+    }
+
     assert(bytes < SIZE_MAX);
 
-    return blk_co_preadv(blk, offset, bytes, NULL,
-                         BDRV_REQ_COPY_ON_READ | BDRV_REQ_PREFETCH);
+    return blk_co_preadv(blk, offset, bytes, NULL, flags);
 }
 
 static void stream_abort(Job *job)
diff --git a/blockdev.c b/blockdev.c
index 2103730..fd824da 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -471,7 +471,7 @@ static BlockBackend *blockdev_init(const char *file, QDict *bs_opts,
     int bdrv_flags = 0;
     int on_read_error, on_write_error;
     bool account_invalid, account_failed;
-    bool writethrough, read_only;
+    bool writethrough, read_only, compress;
     BlockBackend *blk;
     BlockDriverState *bs;
     ThrottleConfig cfg;
@@ -570,6 +570,7 @@ static BlockBackend *blockdev_init(const char *file, QDict *bs_opts,
     }
 
     read_only = qemu_opt_get_bool(opts, BDRV_OPT_READ_ONLY, false);
+    compress = qemu_opt_get_bool(opts, BDRV_OPT_COMPRESS, false);
 
     /* init */
     if ((!file || !*file) && !qdict_size(bs_opts)) {
@@ -595,6 +596,8 @@ static BlockBackend *blockdev_init(const char *file, QDict *bs_opts,
         qdict_set_default_str(bs_opts, BDRV_OPT_READ_ONLY,
                               read_only ? "on" : "off");
         qdict_set_default_str(bs_opts, BDRV_OPT_AUTO_READ_ONLY, "on");
+        qdict_set_default_str(bs_opts, BDRV_OPT_COMPRESS,
+                              compress ? "on" : "off");
         assert((bdrv_flags & BDRV_O_CACHE_MASK) == 0);
 
         if (runstate_check(RUN_STATE_INMIGRATE)) {
@@ -3308,6 +3311,13 @@ void qmp_block_stream(bool has_job_id, const char *job_id, const char *device,
         goto out;
     }
 
+    if (bs->all_write_compressed &&
+        bs->drv->bdrv_co_pwritev_compressed_part == NULL) {
+        error_setg(errp, "Compression is not supported for this drive %s",
+                   bdrv_get_device_name(bs));
+        goto out;
+    }
+
     /* backing_file string overrides base bs filename */
     base_name = has_backing_file ? backing_file : base_name;
 
-- 
1.8.3.1