This brings "incremental" mode to copy-before-write filter: user can specify bitmap so that filter will copy only "dirty" areas.
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsement...@virtuozzo.com> --- qapi/block-core.json | 10 +++++++- block/copy-before-write.c | 51 ++++++++++++++++++++++++++++++++++++++- 2 files changed, 59 insertions(+), 2 deletions(-) diff --git a/qapi/block-core.json b/qapi/block-core.json index 9a5a3641d0..3bab597506 100644 --- a/qapi/block-core.json +++ b/qapi/block-core.json @@ -4171,11 +4171,19 @@ # # @target: The target for copy-before-write operations. # +# @bitmap: If specified, copy-before-write filter will do +# copy-before-write operations only for dirty regions of the +# bitmap. Bitmap size must be equal to length of file and +# target child of the filter. Note also, that bitmap is used +# only to initialize internal bitmap of the process, so further +# modifications (or removing) of specified bitmap doesn't +# influence the filter. +# # Since: 6.2 ## { 'struct': 'BlockdevOptionsCbw', 'base': 'BlockdevOptionsGenericFormat', - 'data': { 'target': 'BlockdevRef' } } + 'data': { 'target': 'BlockdevRef', '*bitmap': 'BlockDirtyBitmap' } } ## # @BlockdevOptions: diff --git a/block/copy-before-write.c b/block/copy-before-write.c index 799223e3fb..91a2288b66 100644 --- a/block/copy-before-write.c +++ b/block/copy-before-write.c @@ -34,6 +34,8 @@ #include "block/copy-before-write.h" +#include "qapi/qapi-visit-block-core.h" + typedef struct BDRVCopyBeforeWriteState { BlockCopyState *bcs; BdrvChild *target; @@ -145,10 +147,53 @@ static void cbw_child_perm(BlockDriverState *bs, BdrvChild *c, } } +static bool cbw_parse_bitmap_option(QDict *options, BdrvDirtyBitmap **bitmap, + Error **errp) +{ + QDict *bitmap_qdict = NULL; + BlockDirtyBitmap *bmp_param = NULL; + Visitor *v = NULL; + bool ret = false; + + *bitmap = NULL; + + qdict_extract_subqdict(options, &bitmap_qdict, "bitmap."); + if (!qdict_size(bitmap_qdict)) { + ret = true; + goto out; + } + + v = qobject_input_visitor_new_flat_confused(bitmap_qdict, errp); + if (!v) { + goto out; + } + + visit_type_BlockDirtyBitmap(v, NULL, &bmp_param, errp); + if (!bmp_param) { + goto out; + } + + *bitmap = block_dirty_bitmap_lookup(bmp_param->node, bmp_param->name, NULL, + errp); + if (!*bitmap) { + goto out; + } + + ret = true; + +out: + qapi_free_BlockDirtyBitmap(bmp_param); + visit_free(v); + qobject_unref(bitmap_qdict); + + return ret; +} + static int cbw_open(BlockDriverState *bs, QDict *options, int flags, Error **errp) { BDRVCopyBeforeWriteState *s = bs->opaque; + BdrvDirtyBitmap *bitmap = NULL; bs->file = bdrv_open_child(NULL, options, "file", bs, &child_of_bds, BDRV_CHILD_FILTERED | BDRV_CHILD_PRIMARY, @@ -163,6 +208,10 @@ static int cbw_open(BlockDriverState *bs, QDict *options, int flags, return -EINVAL; } + if (!cbw_parse_bitmap_option(options, &bitmap, errp)) { + return -EINVAL; + } + bs->total_sectors = bs->file->bs->total_sectors; bs->supported_write_flags = BDRV_REQ_WRITE_UNCHANGED | (BDRV_REQ_FUA & bs->file->bs->supported_write_flags); @@ -170,7 +219,7 @@ 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, NULL, errp); + s->bcs = block_copy_state_new(bs->file, s->target, bitmap, errp); if (!s->bcs) { error_prepend(errp, "Cannot create block-copy-state: "); return -EINVAL; -- 2.31.1