[07/10] blockdev-backup: added support for data compression

Commit Message

Denis V. Lunev May 14, 2016, 12:45 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]>
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]>
---
 blockdev.c           | 10 +++++++++-
 qapi/block-core.json |  1 +
 qmp-commands.hx      |  3 ++-
 3 files changed, 12 insertions(+), 2 deletions(-)

Comments

Eric Blake May 16, 2016, 5 p.m. UTC | #1

On 05/14/2016 06:45 AM, Denis V. Lunev 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
> @@ -941,6 +941,7 @@
>    'data': { 'device': 'str', 'target': 'str',
>              'sync': 'MirrorSyncMode',
>              '*speed': 'int',
> +            '*compress': 'bool',

Missing documentation.

>              '*on-source-error': 'BlockdevOnError',
>              '*on-target-error': 'BlockdevOnError' } }
>  
> diff --git a/qmp-commands.hx b/qmp-commands.hx
> index 8915a0b..6eb5b43 100644
> --- a/qmp-commands.hx
> +++ b/qmp-commands.hx
> @@ -1241,7 +1241,7 @@ EQMP
>  
>      {
>          .name       = "blockdev-backup",
> -        .args_type  = "sync:s,device:B,target:B,speed:i?,"
> +        .args_type  = "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,
>      },
> @@ -1263,6 +1263,7 @@ 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": compress data blocks (if the target format supports it).

Missing mention that it is 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.
>

Stefan Hajnoczi May 27, 2016, 5:57 p.m. UTC | #2

On Sat, May 14, 2016 at 03:45:55PM +0300, Denis V. Lunev 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.
> 
> Signed-off-by: Pavel Butsykin <[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]>
> ---
>  blockdev.c           | 10 +++++++++-
>  qapi/block-core.json |  1 +
>  qmp-commands.hx      |  3 ++-
>  3 files changed, 12 insertions(+), 2 deletions(-)

Aside from the API doc issues that Eric mentioned:

Reviewed-by: Stefan Hajnoczi <[e-mail]>

Patch

diff --git a/blockdev.c b/blockdev.c
index 1ef9e31..ed7df2e 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -1940,6 +1940,7 @@  typedef struct BlockdevBackupState {
 static void do_blockdev_backup(const char *device, const char *target,
                                enum MirrorSyncMode sync,
                                bool has_speed, int64_t speed,
+                               bool has_compress, bool compress,
                                bool has_on_source_error,
                                BlockdevOnError on_source_error,
                                bool has_on_target_error,
@@ -1987,6 +1988,7 @@  static void blockdev_backup_prepare(BlkActionState *common, Error **errp)
     do_blockdev_backup(backup->device, backup->target,
                        backup->sync,
                        backup->has_speed, backup->speed,
+                       backup->has_compress, backup->compress,
                        backup->has_on_source_error, backup->on_source_error,
                        backup->has_on_target_error, backup->on_target_error,
                        common->block_job_txn, &local_err);
@@ -3335,6 +3337,7 @@  BlockDeviceInfoList *qmp_query_named_block_nodes(Error **errp)
 void do_blockdev_backup(const char *device, const char *target,
                          enum MirrorSyncMode sync,
                          bool has_speed, int64_t speed,
+                         bool has_compress, bool compress,
                          bool has_on_source_error,
                          BlockdevOnError on_source_error,
                          bool has_on_target_error,
@@ -3356,6 +3359,9 @@  void do_blockdev_backup(const char *device, const char *target,
     if (!has_on_target_error) {
         on_target_error = BLOCKDEV_ON_ERROR_REPORT;
     }
+    if (!has_compress) {
+        compress = false;
+    }
 
     blk = blk_by_name(device);
     if (!blk) {
@@ -3386,7 +3392,7 @@  void do_blockdev_backup(const char *device, const char *target,
 
     bdrv_ref(target_bs);
     bdrv_set_aio_context(target_bs, aio_context);
-    backup_start(bs, target_bs, speed, sync, NULL, false, on_source_error,
+    backup_start(bs, target_bs, speed, sync, NULL, compress, on_source_error,
                  on_target_error, block_job_cb, bs, txn, &local_err);
     if (local_err != NULL) {
         bdrv_unref(target_bs);
@@ -3399,6 +3405,7 @@  out:
 void qmp_blockdev_backup(const char *device, const char *target,
                          enum MirrorSyncMode sync,
                          bool has_speed, int64_t speed,
+                         bool has_compress, bool compress,
                          bool has_on_source_error,
                          BlockdevOnError on_source_error,
                          bool has_on_target_error,
@@ -3406,6 +3413,7 @@  void qmp_blockdev_backup(const char *device, const char *target,
                          Error **errp)
 {
     do_blockdev_backup(device, target, sync, has_speed, speed,
+                       has_compress, compress,
                        has_on_source_error, on_source_error,
                        has_on_target_error, on_target_error,
                        NULL, errp);
diff --git a/qapi/block-core.json b/qapi/block-core.json
index 85e5950..ceb23d9 100644
--- a/qapi/block-core.json
+++ b/qapi/block-core.json
@@ -941,6 +941,7 @@ 
   'data': { '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 8915a0b..6eb5b43 100644
--- a/qmp-commands.hx
+++ b/qmp-commands.hx
@@ -1241,7 +1241,7 @@  EQMP
 
     {
         .name       = "blockdev-backup",
-        .args_type  = "sync:s,device:B,target:B,speed:i?,"
+        .args_type  = "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,
     },
@@ -1263,6 +1263,7 @@  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": compress data blocks (if the target format supports it).
 - "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.