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author | Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru> | 2024-03-13 18:28:21 +0300 |
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committer | Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru> | 2024-05-28 15:52:15 +0300 |
commit | 0fd05c8d807dc7cd25b2f9bf32dd4135c94acb7a (patch) | |
tree | 3a77f8f16cedb241024faafc1819f1b0a1784110 /block | |
parent | 006e845b5a4cbb1f93a2e8ed22fa648b9d7e4182 (diff) | |
download | qemu-0fd05c8d807dc7cd25b2f9bf32dd4135c94acb7a.zip qemu-0fd05c8d807dc7cd25b2f9bf32dd4135c94acb7a.tar.gz qemu-0fd05c8d807dc7cd25b2f9bf32dd4135c94acb7a.tar.bz2 |
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 'block')
-rw-r--r-- | block/backup.c | 5 | ||||
-rw-r--r-- | block/block-copy.c | 9 | ||||
-rw-r--r-- | block/copy-before-write.c | 15 | ||||
-rw-r--r-- | block/copy-before-write.h | 1 | ||||
-rw-r--r-- | block/replication.c | 4 |
5 files changed, 28 insertions, 6 deletions
diff --git a/block/backup.c b/block/backup.c index ec29d6b..3dd2e22 100644 --- a/block/backup.c +++ b/block/backup.c @@ -356,7 +356,7 @@ 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, @@ -457,7 +457,8 @@ 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 8fca2c3..7e3b378 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; /* @@ -353,6 +354,7 @@ 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(); @@ -418,6 +420,7 @@ 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); @@ -589,6 +592,12 @@ 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 ed2c228..cd65524 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 @@ cbw_child_perm(BlockDriverState *bs, BdrvChild *c, BdrvChildRole role, 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 @@ cbw_child_perm(BlockDriverState *bs, BdrvChild *c, BdrvChildRole role, * start */ *nperm = *nperm | BLK_PERM_CONSISTENT_READ; + if (s->discard_source) { + *nperm = *nperm | BLK_PERM_WRITE; + } + *nshared &= ~(BLK_PERM_WRITE | BLK_PERM_RESIZE); } } @@ -468,7 +475,9 @@ 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: "); return -EINVAL; @@ -535,12 +544,14 @@ static 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(); @@ -553,7 +564,7 @@ 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 6e72bb2..01af0cd 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 ca6bd0a..0415a5e 100644 --- a/block/replication.c +++ b/block/replication.c @@ -582,8 +582,8 @@ 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); |