+++ /dev/null
-From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
-From: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>
-Date: Thu, 11 Apr 2024 11:29:25 +0200
-Subject: [PATCH] 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>
-Signed-off-by: Fiona Ebner <f.ebner@proxmox.com>
-Signed-off-by: Thomas Lamprecht <t.lamprecht@proxmox.com>
----
- block/backup.c | 5 +++--
- block/block-copy.c | 9 +++++++++
- block/copy-before-write.c | 15 +++++++++++++--
- block/copy-before-write.h | 1 +
- block/replication.c | 4 ++--
- blockdev.c | 2 +-
- include/block/block-common.h | 2 ++
- include/block/block-copy.h | 1 +
- include/block/block_int-global-state.h | 2 +-
- qapi/block-core.json | 4 ++++
- 10 files changed, 37 insertions(+), 8 deletions(-)
-
-diff --git a/block/backup.c b/block/backup.c
-index af87fa6aa9..3dc955f625 100644
---- a/block/backup.c
-+++ b/block/backup.c
-@@ -332,7 +332,7 @@ BlockJob *backup_job_create(const char *job_id, BlockDriverState *bs,
- BlockDriverState *target, int64_t speed,
- 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,
-@@ -429,7 +429,8 @@ BlockJob *backup_job_create(const char *job_id, BlockDriverState *bs,
- goto error;
- }
-
-- cbw = bdrv_cbw_append(bs, target, filter_node_name, &bcs, errp);
-+ cbw = bdrv_cbw_append(bs, target, filter_node_name, discard_source,
-+ &bcs, errp);
- if (!cbw) {
- goto error;
- }
-diff --git a/block/block-copy.c b/block/block-copy.c
-index b61685f1a2..3c61e52bae 100644
---- a/block/block-copy.c
-+++ b/block/block-copy.c
-@@ -137,6 +137,7 @@ typedef struct BlockCopyState {
- CoMutex lock;
- int64_t in_flight_bytes;
- BlockCopyMethod method;
-+ bool discard_source;
- BlockReqList reqs;
- QLIST_HEAD(, BlockCopyCallState) calls;
- /*
-@@ -348,6 +349,7 @@ static int64_t block_copy_calculate_cluster_size(BlockDriverState *target,
- BlockCopyState *block_copy_state_new(BdrvChild *source, BdrvChild *target,
- BlockDriverState *copy_bitmap_bs,
- const BdrvDirtyBitmap *bitmap,
-+ bool discard_source,
- Error **errp)
- {
- ERRP_GUARD();
-@@ -409,6 +411,7 @@ BlockCopyState *block_copy_state_new(BdrvChild *source, BdrvChild *target,
- cluster_size),
- };
-
-+ s->discard_source = discard_source;
- block_copy_set_copy_opts(s, false, false);
-
- ratelimit_init(&s->rate_limit);
-@@ -580,6 +583,12 @@ static coroutine_fn int block_copy_task_entry(AioTask *task)
- co_put_to_shres(s->mem, t->req.bytes);
- block_copy_task_end(t, ret);
-
-+ if (s->discard_source && ret == 0) {
-+ int64_t nbytes =
-+ MIN(t->req.offset + t->req.bytes, s->len) - t->req.offset;
-+ bdrv_co_pdiscard(s->source, t->req.offset, nbytes);
-+ }
-+
- return ret;
- }
-
-diff --git a/block/copy-before-write.c b/block/copy-before-write.c
-index d3b95bd600..3503702d71 100644
---- a/block/copy-before-write.c
-+++ b/block/copy-before-write.c
-@@ -44,6 +44,7 @@ typedef struct BDRVCopyBeforeWriteState {
- BdrvChild *target;
- OnCbwError on_cbw_error;
- uint32_t cbw_timeout_ns;
-+ bool discard_source;
-
- /*
- * @lock: protects access to @access_bitmap, @done_bitmap and
-@@ -357,6 +358,8 @@ static void cbw_child_perm(BlockDriverState *bs, BdrvChild *c,
- uint64_t perm, uint64_t shared,
- uint64_t *nperm, uint64_t *nshared)
- {
-+ BDRVCopyBeforeWriteState *s = bs->opaque;
-+
- if (!(role & BDRV_CHILD_FILTERED)) {
- /*
- * Target child
-@@ -381,6 +384,10 @@ static void cbw_child_perm(BlockDriverState *bs, BdrvChild *c,
- * start
- */
- *nperm = *nperm | BLK_PERM_CONSISTENT_READ;
-+ if (s->discard_source) {
-+ *nperm = *nperm | BLK_PERM_WRITE;
-+ }
-+
- *nshared &= ~(BLK_PERM_WRITE | BLK_PERM_RESIZE);
- }
- }
-@@ -470,7 +477,9 @@ static int cbw_open(BlockDriverState *bs, QDict *options, int flags,
- ((BDRV_REQ_FUA | BDRV_REQ_MAY_UNMAP | BDRV_REQ_NO_FALLBACK) &
- bs->file->bs->supported_zero_flags);
-
-- s->bcs = block_copy_state_new(bs->file, s->target, bs, bitmap, errp);
-+ s->discard_source = flags & BDRV_O_CBW_DISCARD_SOURCE;
-+ s->bcs = block_copy_state_new(bs->file, s->target, bs, bitmap,
-+ flags & BDRV_O_CBW_DISCARD_SOURCE, errp);
- if (!s->bcs) {
- error_prepend(errp, "Cannot create block-copy-state: ");
- ret = -EINVAL;
-@@ -544,12 +553,14 @@ BlockDriver bdrv_cbw_filter = {
- BlockDriverState *bdrv_cbw_append(BlockDriverState *source,
- BlockDriverState *target,
- const char *filter_node_name,
-+ bool discard_source,
- BlockCopyState **bcs,
- Error **errp)
- {
- BDRVCopyBeforeWriteState *state;
- BlockDriverState *top;
- QDict *opts;
-+ int flags = BDRV_O_RDWR | (discard_source ? BDRV_O_CBW_DISCARD_SOURCE : 0);
-
- assert(source->total_sectors == target->total_sectors);
- GLOBAL_STATE_CODE();
-@@ -562,7 +573,7 @@ BlockDriverState *bdrv_cbw_append(BlockDriverState *source,
- qdict_put_str(opts, "file", bdrv_get_node_name(source));
- qdict_put_str(opts, "target", bdrv_get_node_name(target));
-
-- top = bdrv_insert_node(source, opts, BDRV_O_RDWR, errp);
-+ top = bdrv_insert_node(source, opts, flags, errp);
- if (!top) {
- return NULL;
- }
-diff --git a/block/copy-before-write.h b/block/copy-before-write.h
-index 6e72bb25e9..01af0cd3c4 100644
---- a/block/copy-before-write.h
-+++ b/block/copy-before-write.h
-@@ -39,6 +39,7 @@
- BlockDriverState *bdrv_cbw_append(BlockDriverState *source,
- BlockDriverState *target,
- const char *filter_node_name,
-+ bool discard_source,
- BlockCopyState **bcs,
- Error **errp);
- void bdrv_cbw_drop(BlockDriverState *bs);
-diff --git a/block/replication.c b/block/replication.c
-index ea4bf1aa80..39ad78cf98 100644
---- a/block/replication.c
-+++ b/block/replication.c
-@@ -579,8 +579,8 @@ static void replication_start(ReplicationState *rs, ReplicationMode mode,
-
- s->backup_job = backup_job_create(
- NULL, s->secondary_disk->bs, s->hidden_disk->bs,
-- 0, MIRROR_SYNC_MODE_NONE, NULL, 0, false, NULL,
-- &perf,
-+ 0, MIRROR_SYNC_MODE_NONE, NULL, 0, false, false,
-+ NULL, &perf,
- BLOCKDEV_ON_ERROR_REPORT,
- BLOCKDEV_ON_ERROR_REPORT, JOB_INTERNAL,
- backup_job_completed, bs, NULL, &local_err);
-diff --git a/blockdev.c b/blockdev.c
-index 7793143d76..ce3fef924c 100644
---- a/blockdev.c
-+++ b/blockdev.c
-@@ -2802,7 +2802,7 @@ static BlockJob *do_backup_common(BackupCommon *backup,
-
- job = backup_job_create(backup->job_id, bs, target_bs, backup->speed,
- backup->sync, bmap, backup->bitmap_mode,
-- backup->compress,
-+ backup->compress, backup->discard_source,
- backup->filter_node_name,
- &perf,
- backup->on_source_error,
-diff --git a/include/block/block-common.h b/include/block/block-common.h
-index e15395f2cb..913a8b259c 100644
---- a/include/block/block-common.h
-+++ b/include/block/block-common.h
-@@ -234,6 +234,8 @@ 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 32f0f9858a..546f2b5532 100644
---- a/include/block/block_int-global-state.h
-+++ b/include/block/block_int-global-state.h
-@@ -189,7 +189,7 @@ 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,
-diff --git a/qapi/block-core.json b/qapi/block-core.json
-index 09de550c95..4297e5beda 100644
---- a/qapi/block-core.json
-+++ b/qapi/block-core.json
-@@ -1816,6 +1816,9 @@
- # node specified by @drive. If this option is not given, a node
- # name is autogenerated. (Since: 4.2)
- #
-+# @discard-source: Discard blocks on source which are already copied
-+# to the target. (Since 9.0)
-+#
- # @x-perf: Performance options. (Since 6.0)
- #
- # Features:
-@@ -1837,6 +1840,7 @@
- '*on-target-error': 'BlockdevOnError',
- '*auto-finalize': 'bool', '*auto-dismiss': 'bool',
- '*filter-node-name': 'str',
-+ '*discard-source': 'bool',
- '*x-perf': { 'type': 'BackupPerf',
- 'features': [ 'unstable' ] } } }
-
projects / pve-qemu.git / blobdiff