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block/copy-before-write: add bitmap open parameter 

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 <vsementsov@virtuozzo.com>
Message-Id: <20220303194349.2304213-5-vsementsov@virtuozzo.com>
Signed-off-by: Hanna Reitz <hreitz@redhat.com>
This commit is contained in:
Vladimir Sementsov-Ogievskiy 2022-03-03 20:43:37 +01:00 committed by Hanna Reitz
parent 1f7252e868
commit 5f3a3cd7f0
2 changed files with 59 additions and 2 deletions
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51
block/copy-before-write.c
View File

@ -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;

10
qapi/block-core.json
View File

@ -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 7.0)
#
# Since: 6.2
##
{ 'struct': 'BlockdevOptionsCbw',
'base': 'BlockdevOptionsGenericFormat',
'data': { 'target': 'BlockdevRef' } }
'data': { 'target': 'BlockdevRef', '*bitmap': 'BlockDirtyBitmap' } }
##
# @BlockdevOptions: