diff options
| author | Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru> | 2024-03-13 18:28:21 +0300 |
|---|---|---|
| committer | Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru> | 2024-05-28 15:52:15 +0300 |
| commit | 0fd05c8d807dc7cd25b2f9bf32dd4135c94acb7a (patch) | |
| tree | 3a77f8f16cedb241024faafc1819f1b0a1784110 /include/block | |
| parent | 006e845b5a4cbb1f93a2e8ed22fa648b9d7e4182 (diff) | |
qapi: blockdev-backup: add discard-source parameter
Add a parameter that enables discard-after-copy. That is mostly useful
in "push backup with fleecing" scheme, when source is snapshot-access
format driver node, based on copy-before-write filter snapshot-access
API:
[guest] [snapshot-access] ~~ blockdev-backup ~~> [backup target]
| |
| root | file
v v
[copy-before-write]
| |
| file | target
v v
[active disk] [temp.img]
In this case discard-after-copy does two things:
- discard data in temp.img to save disk space
- avoid further copy-before-write operation in discarded area
Note that we have to declare WRITE permission on source in
copy-before-write filter, for discard to work. Still we can't take it
unconditionally, as it will break normal backup from RO source. So, we
have to add a parameter and pass it thorough bdrv_open flags.
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>
Reviewed-by: Fiona Ebner <f.ebner@proxmox.com>
Tested-by: Fiona Ebner <f.ebner@proxmox.com>
Acked-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20240313152822.626493-5-vsementsov@yandex-team.ru>
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>
Diffstat (limited to 'include/block')
| -rw-r--r-- | include/block/block-common.h | 2 | ||||
| -rw-r--r-- | include/block/block-copy.h | 1 | ||||
| -rw-r--r-- | include/block/block_int-global-state.h | 2 |
3 files changed, 4 insertions, 1 deletions
diff --git a/include/block/block-common.h b/include/block/block-common.h index a846023a09..338fe5ff7a 100644 --- a/include/block/block-common.h +++ b/include/block/block-common.h @@ -243,6 +243,8 @@ typedef enum { read-write fails */ #define BDRV_O_IO_URING 0x40000 /* use io_uring instead of the thread pool */ +#define BDRV_O_CBW_DISCARD_SOURCE 0x80000 /* for copy-before-write filter */ + #define BDRV_O_CACHE_MASK (BDRV_O_NOCACHE | BDRV_O_NO_FLUSH) diff --git a/include/block/block-copy.h b/include/block/block-copy.h index 8b41643bfa..bdc703bacd 100644 --- a/include/block/block-copy.h +++ b/include/block/block-copy.h @@ -27,6 +27,7 @@ typedef struct BlockCopyCallState BlockCopyCallState; BlockCopyState *block_copy_state_new(BdrvChild *source, BdrvChild *target, BlockDriverState *copy_bitmap_bs, const BdrvDirtyBitmap *bitmap, + bool discard_source, Error **errp); /* Function should be called prior any actual copy request */ diff --git a/include/block/block_int-global-state.h b/include/block/block_int-global-state.h index d2201e27f4..eb2d92a226 100644 --- a/include/block/block_int-global-state.h +++ b/include/block/block_int-global-state.h @@ -193,7 +193,7 @@ BlockJob *backup_job_create(const char *job_id, BlockDriverState *bs, MirrorSyncMode sync_mode, BdrvDirtyBitmap *sync_bitmap, BitmapSyncMode bitmap_mode, - bool compress, + bool compress, bool discard_source, const char *filter_node_name, BackupPerf *perf, BlockdevOnError on_source_error, |