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blockdev: n-ary bitmap merge 

Especially outside of transactions, it is helpful to provide
all-or-nothing semantics for bitmap merges. This facilitates
the coalescing of multiple bitmaps into a single target for
the "checkpoint" interpretation when assembling bitmaps that
represent arbitrary points in time from component bitmaps.

This is an incompatible change from the preliminary version
of the API.

Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-Id: <20181221093529.23855-4-jsnow@redhat.com>
Signed-off-by: Eric Blake <eblake@redhat.com>
This commit is contained in:
John Snow 2018-12-21 04:35:21 -05:00 committed by Eric Blake
parent 07d5a8df6a
commit 360d4e4e9a
2 changed files with 62 additions and 35 deletions
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75
blockdev.c
View File

@ -2119,33 +2119,28 @@ static void block_dirty_bitmap_disable_abort(BlkActionState *common)
}
}
static BdrvDirtyBitmap *do_block_dirty_bitmap_merge(const char *node,
const char *target,
strList *bitmaps,
HBitmap **backup,
Error **errp);
static void block_dirty_bitmap_merge_prepare(BlkActionState *common,
Error **errp)
{
BlockDirtyBitmapMerge *action;
BlockDirtyBitmapState *state = DO_UPCAST(BlockDirtyBitmapState,
common, common);
BdrvDirtyBitmap *merge_source;
if (action_check_completion_mode(common, errp) < 0) {
return;
}
action = common->action->u.x_block_dirty_bitmap_merge.data;
state->bitmap = block_dirty_bitmap_lookup(action->node,
action->dst_name,
&state->bs,
errp);
if (!state->bitmap) {
return;
}
merge_source = bdrv_find_dirty_bitmap(state->bs, action->src_name);
if (!merge_source) {
return;
}
bdrv_merge_dirty_bitmap(state->bitmap, merge_source, &state->backup, errp);
state->bitmap = do_block_dirty_bitmap_merge(action->node, action->target,
action->bitmaps, &state->backup,
errp);
}
static void abort_prepare(BlkActionState *common, Error **errp)
@ -2977,24 +2972,56 @@ void qmp_x_block_dirty_bitmap_disable(const char *node, const char *name,
bdrv_disable_dirty_bitmap(bitmap);
}
void qmp_x_block_dirty_bitmap_merge(const char *node, const char *dst_name,
const char *src_name, Error **errp)
static BdrvDirtyBitmap *do_block_dirty_bitmap_merge(const char *node,
const char *target,
strList *bitmaps,
HBitmap **backup,
Error **errp)
{
BlockDriverState *bs;
BdrvDirtyBitmap *dst, *src;
BdrvDirtyBitmap *dst, *src, *anon;
strList *lst;
Error *local_err = NULL;
dst = block_dirty_bitmap_lookup(node, dst_name, &bs, errp);
dst = block_dirty_bitmap_lookup(node, target, &bs, errp);
if (!dst) {
return;
return NULL;
}
src = bdrv_find_dirty_bitmap(bs, src_name);
if (!src) {
error_setg(errp, "Dirty bitmap '%s' not found", src_name);
return;
anon = bdrv_create_dirty_bitmap(bs, bdrv_dirty_bitmap_granularity(dst),
NULL, errp);
if (!anon) {
return NULL;
}
bdrv_merge_dirty_bitmap(dst, src, NULL, errp);
for (lst = bitmaps; lst; lst = lst->next) {
src = bdrv_find_dirty_bitmap(bs, lst->value);
if (!src) {
error_setg(errp, "Dirty bitmap '%s' not found", lst->value);
dst = NULL;
goto out;
}
bdrv_merge_dirty_bitmap(anon, src, NULL, &local_err);
if (local_err) {
error_propagate(errp, local_err);
dst = NULL;
goto out;
}
}
/* Merge into dst; dst is unchanged on failure. */
bdrv_merge_dirty_bitmap(dst, anon, backup, errp);
out:
bdrv_release_dirty_bitmap(bs, anon);
return dst;
}
void qmp_x_block_dirty_bitmap_merge(const char *node, const char *target,
strList *bitmaps, Error **errp)
{
do_block_dirty_bitmap_merge(node, target, bitmaps, NULL, errp);
}
BlockDirtyBitmapSha256 *qmp_x_debug_block_dirty_bitmap_sha256(const char *node,

22
qapi/block-core.json
View File

@ -1821,14 +1821,14 @@
#
# @node: name of device/node which the bitmap is tracking
#
# @dst_name: name of the destination dirty bitmap
# @target: name of the destination dirty bitmap
#
# @src_name: name of the source dirty bitmap
# @bitmaps: name(s) of the source dirty bitmap(s)
#
# Since: 3.0
##
{ 'struct': 'BlockDirtyBitmapMerge',
'data': { 'node': 'str', 'dst_name': 'str', 'src_name': 'str' } }
'data': { 'node': 'str', 'target': 'str', 'bitmaps': ['str'] } }
##
# @block-dirty-bitmap-add:
@ -1943,23 +1943,23 @@
##
# @x-block-dirty-bitmap-merge:
#
# FIXME: Rename @src_name and @dst_name to src-name and dst-name.
#
# Merge @src_name dirty bitmap to @dst_name dirty bitmap. @src_name dirty
# bitmap is unchanged. On error, @dst_name is unchanged.
# Merge dirty bitmaps listed in @bitmaps to the @target dirty bitmap.
# The @bitmaps dirty bitmaps are unchanged.
# On error, @target is unchanged.
#
# Returns: nothing on success
# If @node is not a valid block device, DeviceNotFound
# If @dst_name or @src_name is not found, GenericError
# If bitmaps has different sizes or granularities, GenericError
# If any bitmap in @bitmaps or @target is not found, GenericError
# If any of the bitmaps have different sizes or granularities,
# GenericError
#
# Since: 3.0
#
# Example:
#
# -> { "execute": "x-block-dirty-bitmap-merge",
# "arguments": { "node": "drive0", "dst_name": "bitmap0",
# "src_name": "bitmap1" } }
# "arguments": { "node": "drive0", "target": "bitmap0",
# "bitmaps": ["bitmap1"] } }
# <- { "return": {} }
#
##