[PULL,27/42] blockdev-backup: added support for data compression

Commit Message

Kevin Wolf Sept. 5, 2016, 6:13 p.m. UTC

From: Pavel Butsykin <[e-mail]>

The idea is simple - backup is "written-once" data. It is written block
by block and it is large enough. It would be nice to save storage
space and compress it.

Signed-off-by: Pavel Butsykin <[e-mail]>
Reviewed-by: Stefan Hajnoczi <[e-mail]>
Signed-off-by: Denis V. Lunev <[e-mail]>
CC: Jeff Cody <[e-mail]>
CC: Markus Armbruster <[e-mail]>
CC: Eric Blake <[e-mail]>
CC: John Snow <[e-mail]>
CC: Stefan Hajnoczi <[e-mail]>
CC: Kevin Wolf <[e-mail]>
Signed-off-by: Kevin Wolf <[e-mail]>
---
 blockdev.c           | 7 +++++--
 qapi/block-core.json | 4 ++++
 qmp-commands.hx      | 4 +++-
 3 files changed, 12 insertions(+), 3 deletions(-)

Comments

Eric Blake Sept. 16, 2016, 3:15 p.m. UTC | #1

On 09/05/2016 01:13 PM, Kevin Wolf wrote:
> From: Pavel Butsykin <[e-mail]>
> 
> The idea is simple - backup is "written-once" data. It is written block
> by block and it is large enough. It would be nice to save storage
> space and compress it.
> 

> +++ b/qapi/block-core.json
> @@ -939,6 +939,9 @@
>  # @speed: #optional the maximum speed, in bytes per second. The default is 0,
>  #         for unlimited.
>  #
> +# @compress: #optional true to compress data, if the target format supports it.
> +#            (default: false) (since 2.7)

Again, 2.8.

Patch

diff --git a/blockdev.c b/blockdev.c
index f5857d0..97062e3 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -3254,6 +3254,9 @@  void do_blockdev_backup(BlockdevBackup *backup, BlockJobTxn *txn, Error **errp)
     if (!backup->has_job_id) {
         backup->job_id = NULL;
     }
+    if (!backup->has_compress) {
+        backup->compress = false;
+    }
 
     bs = qmp_get_root_bs(backup->device, errp);
     if (!bs) {
@@ -3280,8 +3283,8 @@  void do_blockdev_backup(BlockdevBackup *backup, BlockJobTxn *txn, Error **errp)
         }
     }
     backup_start(backup->job_id, bs, target_bs, backup->speed, backup->sync,
-                 NULL, false, backup->on_source_error, backup->on_target_error,
-                 block_job_cb, bs, txn, &local_err);
+                 NULL, backup->compress, backup->on_source_error,
+                 backup->on_target_error, block_job_cb, bs, txn, &local_err);
     if (local_err != NULL) {
         error_propagate(errp, local_err);
     }
diff --git a/qapi/block-core.json b/qapi/block-core.json
index 300a68b..31f9990 100644
--- a/qapi/block-core.json
+++ b/qapi/block-core.json
@@ -939,6 +939,9 @@ 
 # @speed: #optional the maximum speed, in bytes per second. The default is 0,
 #         for unlimited.
 #
+# @compress: #optional true to compress data, if the target format supports it.
+#            (default: false) (since 2.7)
+#
 # @on-source-error: #optional the action to take on an error on the source,
 #                   default 'report'.  'stop' and 'enospc' can only be used
 #                   if the block device supports io-status (see BlockInfo).
@@ -957,6 +960,7 @@ 
   'data': { '*job-id': 'str', 'device': 'str', 'target': 'str',
             'sync': 'MirrorSyncMode',
             '*speed': 'int',
+            '*compress': 'bool',
             '*on-source-error': 'BlockdevOnError',
             '*on-target-error': 'BlockdevOnError' } }
 
diff --git a/qmp-commands.hx b/qmp-commands.hx
index d1593c9..ba2a916 100644
--- a/qmp-commands.hx
+++ b/qmp-commands.hx
@@ -1275,7 +1275,7 @@  EQMP
 
     {
         .name       = "blockdev-backup",
-        .args_type  = "job-id:s?,sync:s,device:B,target:B,speed:i?,"
+        .args_type  = "job-id:s?,sync:s,device:B,target:B,speed:i?,compress:b?,"
                       "on-source-error:s?,on-target-error:s?",
         .mhandler.cmd_new = qmp_marshal_blockdev_backup,
     },
@@ -1299,6 +1299,8 @@  Arguments:
           sectors allocated in the topmost image, or "none" to only replicate
           new I/O (MirrorSyncMode).
 - "speed": the maximum speed, in bytes per second (json-int, optional)
+- "compress": true to compress data, if the target format supports it.
+              (json-bool, optional, default false)
 - "on-source-error": the action to take on an error on the source, default
                      'report'.  'stop' and 'enospc' can only be used
                      if the block device supports io-status.