block: simplify handling of try to merge different sized bitmaps

We have too much logic to simply check that bitmaps are of the same
size. Let's just define that hbitmap_merge() and
bdrv_dirty_bitmap_merge_internal() require their argument bitmaps be of
same size, this simplifies things.

Let's look through the callers:

For backup_init_bcs_bitmap() we already assert that merge can't fail.

In bdrv_reclaim_dirty_bitmap_locked() we gracefully handle the error
that can't happen: successor always has same size as its parent, drop
this logic.

In bdrv_merge_dirty_bitmap() we already has assertion and separate
check. Make the check explicit and improve error message.

Signed-off-by: Vladimir Sementsov-Ogievskiy <v.sementsov-og@mail.ru>
Reviewed-by: Nikita Lapshin <nikita.lapshin@virtuozzo.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Message-Id: <20220517111206.23585-4-v.sementsov-og@mail.ru>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This commit is contained in:
Vladimir Sementsov-Ogievskiy 2022-05-17 14:12:06 +03:00 committed by Kevin Wolf
parent 58cbfbdf73
commit 618af89e55
5 changed files with 23 additions and 51 deletions

View File

@ -228,15 +228,13 @@ out:
static void backup_init_bcs_bitmap(BackupBlockJob *job)
{
bool ret;
uint64_t estimate;
BdrvDirtyBitmap *bcs_bitmap = block_copy_dirty_bitmap(job->bcs);
if (job->sync_mode == MIRROR_SYNC_MODE_BITMAP) {
bdrv_clear_dirty_bitmap(bcs_bitmap, NULL);
ret = bdrv_dirty_bitmap_merge_internal(bcs_bitmap, job->sync_bitmap,
NULL, true);
assert(ret);
bdrv_dirty_bitmap_merge_internal(bcs_bitmap, job->sync_bitmap, NULL,
true);
} else if (job->sync_mode == MIRROR_SYNC_MODE_TOP) {
/*
* We can't hog the coroutine to initialize this thoroughly.

View File

@ -309,10 +309,7 @@ BdrvDirtyBitmap *bdrv_reclaim_dirty_bitmap_locked(BdrvDirtyBitmap *parent,
return NULL;
}
if (!hbitmap_merge(parent->bitmap, successor->bitmap, parent->bitmap)) {
error_setg(errp, "Merging of parent and successor bitmap failed");
return NULL;
}
hbitmap_merge(parent->bitmap, successor->bitmap, parent->bitmap);
parent->disabled = successor->disabled;
parent->busy = false;
@ -912,13 +909,15 @@ bool bdrv_merge_dirty_bitmap(BdrvDirtyBitmap *dest, const BdrvDirtyBitmap *src,
goto out;
}
if (!hbitmap_can_merge(dest->bitmap, src->bitmap)) {
error_setg(errp, "Bitmaps are incompatible and can't be merged");
if (bdrv_dirty_bitmap_size(src) != bdrv_dirty_bitmap_size(dest)) {
error_setg(errp, "Bitmaps are of different sizes (destination size is %"
PRId64 ", source size is %" PRId64 ") and can't be merged",
bdrv_dirty_bitmap_size(dest), bdrv_dirty_bitmap_size(src));
goto out;
}
ret = bdrv_dirty_bitmap_merge_internal(dest, src, backup, false);
assert(ret);
bdrv_dirty_bitmap_merge_internal(dest, src, backup, false);
ret = true;
out:
bdrv_dirty_bitmaps_unlock(dest->bs);
@ -932,17 +931,16 @@ out:
/**
* bdrv_dirty_bitmap_merge_internal: merge src into dest.
* Does NOT check bitmap permissions; not suitable for use as public API.
* @dest, @src and @backup (if not NULL) must have same size.
*
* @backup: If provided, make a copy of dest here prior to merge.
* @lock: If true, lock and unlock bitmaps on the way in/out.
* returns true if the merge succeeded; false if unattempted.
*/
bool bdrv_dirty_bitmap_merge_internal(BdrvDirtyBitmap *dest,
void bdrv_dirty_bitmap_merge_internal(BdrvDirtyBitmap *dest,
const BdrvDirtyBitmap *src,
HBitmap **backup,
bool lock)
{
bool ret;
IO_CODE();
assert(!bdrv_dirty_bitmap_readonly(dest));
@ -959,9 +957,9 @@ bool bdrv_dirty_bitmap_merge_internal(BdrvDirtyBitmap *dest,
if (backup) {
*backup = dest->bitmap;
dest->bitmap = hbitmap_alloc(dest->size, hbitmap_granularity(*backup));
ret = hbitmap_merge(*backup, src->bitmap, dest->bitmap);
hbitmap_merge(*backup, src->bitmap, dest->bitmap);
} else {
ret = hbitmap_merge(dest->bitmap, src->bitmap, dest->bitmap);
hbitmap_merge(dest->bitmap, src->bitmap, dest->bitmap);
}
if (lock) {
@ -970,6 +968,4 @@ bool bdrv_dirty_bitmap_merge_internal(BdrvDirtyBitmap *dest,
bdrv_dirty_bitmaps_unlock(src->bs);
}
}
return ret;
}

View File

@ -102,7 +102,7 @@ bool blk_dev_is_tray_open(BlockBackend *blk);
void bdrv_set_dirty(BlockDriverState *bs, int64_t offset, int64_t bytes);
void bdrv_clear_dirty_bitmap(BdrvDirtyBitmap *bitmap, HBitmap **out);
bool bdrv_dirty_bitmap_merge_internal(BdrvDirtyBitmap *dest,
void bdrv_dirty_bitmap_merge_internal(BdrvDirtyBitmap *dest,
const BdrvDirtyBitmap *src,
HBitmap **backup, bool lock);

View File

@ -76,20 +76,9 @@ void hbitmap_truncate(HBitmap *hb, uint64_t size);
*
* Store result of merging @a and @b into @result.
* @result is allowed to be equal to @a or @b.
*
* Return true if the merge was successful,
* false if it was not attempted.
* All bitmaps must have same size.
*/
bool hbitmap_merge(const HBitmap *a, const HBitmap *b, HBitmap *result);
/**
* hbitmap_can_merge:
*
* hbitmap_can_merge(a, b) && hbitmap_can_merge(a, result) is sufficient and
* necessary for hbitmap_merge will not fail.
*
*/
bool hbitmap_can_merge(const HBitmap *a, const HBitmap *b);
void hbitmap_merge(const HBitmap *a, const HBitmap *b, HBitmap *result);
/**
* hbitmap_empty:

View File

@ -873,11 +873,6 @@ void hbitmap_truncate(HBitmap *hb, uint64_t size)
}
}
bool hbitmap_can_merge(const HBitmap *a, const HBitmap *b)
{
return (a->orig_size == b->orig_size);
}
/**
* hbitmap_sparse_merge: performs dst = dst | src
* works with differing granularities.
@ -901,28 +896,24 @@ static void hbitmap_sparse_merge(HBitmap *dst, const HBitmap *src)
* Given HBitmaps A and B, let R := A (BITOR) B.
* Bitmaps A and B will not be modified,
* except when bitmap R is an alias of A or B.
*
* @return true if the merge was successful,
* false if it was not attempted.
* Bitmaps must have same size.
*/
bool hbitmap_merge(const HBitmap *a, const HBitmap *b, HBitmap *result)
void hbitmap_merge(const HBitmap *a, const HBitmap *b, HBitmap *result)
{
int i;
uint64_t j;
if (!hbitmap_can_merge(a, b) || !hbitmap_can_merge(a, result)) {
return false;
}
assert(hbitmap_can_merge(b, result));
assert(a->orig_size == result->orig_size);
assert(b->orig_size == result->orig_size);
if ((!hbitmap_count(a) && result == b) ||
(!hbitmap_count(b) && result == a)) {
return true;
return;
}
if (!hbitmap_count(a) && !hbitmap_count(b)) {
hbitmap_reset_all(result);
return true;
return;
}
if (a->granularity != b->granularity) {
@ -935,7 +926,7 @@ bool hbitmap_merge(const HBitmap *a, const HBitmap *b, HBitmap *result)
if (b != result) {
hbitmap_sparse_merge(result, b);
}
return true;
return;
}
/* This merge is O(size), as BITS_PER_LONG and HBITMAP_LEVELS are constant.
@ -951,8 +942,6 @@ bool hbitmap_merge(const HBitmap *a, const HBitmap *b, HBitmap *result)
/* Recompute the dirty count */
result->count = hb_count_between(result, 0, result->size - 1);
return true;
}
char *hbitmap_sha256(const HBitmap *bitmap, Error **errp)