We are still using an internal hbitmap that tracks a size in sectors,
with the granularity scaled down accordingly, because it lets us
use a shortcut for our iterators which are currently sector-based.
But there's no reason we can't track the dirty bitmap size in bytes,
since it is (mostly) an internal-only variable (remember, the size
is how many bytes are covered by the bitmap, not how many bytes the
bitmap occupies). Furthermore, we're already reporting bytes for
bdrv_dirty_bitmap_granularity(); mixing bytes and sectors in our
return values is a recipe for confusion. A later cleanup will
convert dirty bitmap internals to be entirely byte-based,
eliminating the intermediate sector rounding added here; and
technically, since bdrv_getlength() already rounds up to sectors,
our use of DIV_ROUND_UP is more for theoretical completeness than
for any actual rounding.
The only external caller in qcow2-bitmap.c is temporarily more verbose
(because it is still using sector-based math), but will later be
switched to track progress by bytes instead of sectors.
Use is_power_of_2() while at it, instead of open-coding that, and
add an assertion where bdrv_getlength() should not fail.
Signed-off-by: Eric Blake <ebl...@redhat.com>
Reviewed-by: John Snow <js...@redhat.com>
---
v6: no change
v5: fix bdrv_dirty_bitmap_truncate [John], drop R-b
v4: retitle from "Track size in bytes", rebase to persistent bitmaps,
round up when converting bytes to sectors
v3: no change
v2: tweak commit message, no code change
---
block/dirty-bitmap.c | 26 +++++++++++++++-----------
block/qcow2-bitmap.c | 14 ++++++++------
2 files changed, 23 insertions(+), 17 deletions(-)
diff --git a/block/dirty-bitmap.c b/block/dirty-bitmap.c
index 42a55e4a4b..e65ec4f7ec 100644
--- a/block/dirty-bitmap.c
+++ b/block/dirty-bitmap.c
@@ -1,7 +1,7 @@
/*
* Block Dirty Bitmap
*
- * Copyright (c) 2016 Red Hat. Inc
+ * Copyright (c) 2016-2017 Red Hat. Inc
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to
deal
@@ -42,7 +42,7 @@ struct BdrvDirtyBitmap {
HBitmap *meta; /* Meta dirty bitmap */
BdrvDirtyBitmap *successor; /* Anonymous child; implies frozen status */
char *name; /* Optional non-empty unique ID */
- int64_t size; /* Size of the bitmap (Number of sectors) */
+ int64_t size; /* Size of the bitmap, in bytes */
bool disabled; /* Bitmap is disabled. It ignores all writes to
the device */
int active_iterators; /* How many iterators are active */
@@ -115,17 +115,14 @@ BdrvDirtyBitmap
*bdrv_create_dirty_bitmap(BlockDriverState *bs,
{
int64_t bitmap_size;
BdrvDirtyBitmap *bitmap;
- uint32_t sector_granularity;
- assert((granularity & (granularity - 1)) == 0);
+ assert(is_power_of_2(granularity) && granularity >= BDRV_SECTOR_SIZE);
if (name && bdrv_find_dirty_bitmap(bs, name)) {
error_setg(errp, "Bitmap already exists: %s", name);
return NULL;
}
- sector_granularity = granularity >> BDRV_SECTOR_BITS;
- assert(sector_granularity);
- bitmap_size = bdrv_nb_sectors(bs);
+ bitmap_size = bdrv_getlength(bs);
if (bitmap_size < 0) {
error_setg_errno(errp, -bitmap_size, "could not get length of device");
errno = -bitmap_size;
@@ -133,7 +130,12 @@ BdrvDirtyBitmap *bdrv_create_dirty_bitmap(BlockDriverState
*bs,
}
bitmap = g_new0(BdrvDirtyBitmap, 1);
bitmap->mutex = &bs->dirty_bitmap_mutex;
- bitmap->bitmap = hbitmap_alloc(bitmap_size, ctz32(sector_granularity));
+ /*
+ * TODO - let hbitmap track full granularity. For now, it is tracking
+ * only sector granularity, as a shortcut for our iterators.
+ */
+ bitmap->bitmap = hbitmap_alloc(DIV_ROUND_UP(bitmap_size, BDRV_SECTOR_SIZE),
+ ctz32(granularity) - BDRV_SECTOR_BITS);
bitmap->size = bitmap_size;
bitmap->name = g_strdup(name);
bitmap->disabled = false;
@@ -305,13 +307,14 @@ BdrvDirtyBitmap
*bdrv_reclaim_dirty_bitmap(BlockDriverState *bs,
void bdrv_dirty_bitmap_truncate(BlockDriverState *bs)
{
BdrvDirtyBitmap *bitmap;
- uint64_t size = bdrv_nb_sectors(bs);
+ int64_t size = bdrv_getlength(bs);
+ assert(size >= 0);
bdrv_dirty_bitmaps_lock(bs);
QLIST_FOREACH(bitmap, &bs->dirty_bitmaps, list) {
assert(!bdrv_dirty_bitmap_frozen(bitmap));
assert(!bitmap->active_iterators);
- hbitmap_truncate(bitmap->bitmap, size);
+ hbitmap_truncate(bitmap->bitmap, DIV_ROUND_UP(size, BDRV_SECTOR_SIZE));
bitmap->size = size;
}
bdrv_dirty_bitmaps_unlock(bs);
@@ -549,7 +552,8 @@ void bdrv_clear_dirty_bitmap(BdrvDirtyBitmap *bitmap,
HBitmap **out)
hbitmap_reset_all(bitmap->bitmap);
} else {
HBitmap *backup = bitmap->bitmap;
- bitmap->bitmap = hbitmap_alloc(bitmap->size,
+ bitmap->bitmap = hbitmap_alloc(DIV_ROUND_UP(bitmap->size,
+ BDRV_SECTOR_SIZE),
hbitmap_granularity(backup));
*out = backup;
}
diff --git a/block/qcow2-bitmap.c b/block/qcow2-bitmap.c
index b3ee4c794a..65122e9ae1 100644
--- a/block/qcow2-bitmap.c
+++ b/block/qcow2-bitmap.c
@@ -295,10 +295,11 @@ static int load_bitmap_data(BlockDriverState *bs,
BDRVQcow2State *s = bs->opaque;
uint64_t sector, sbc;
uint64_t bm_size = bdrv_dirty_bitmap_size(bitmap);
+ uint64_t bm_sectors = DIV_ROUND_UP(bm_size, BDRV_SECTOR_SIZE);
uint8_t *buf = NULL;
uint64_t i, tab_size =
size_to_clusters(s,
- bdrv_dirty_bitmap_serialization_size(bitmap, 0, bm_size));
+ bdrv_dirty_bitmap_serialization_size(bitmap, 0, bm_sectors));
if (tab_size != bitmap_table_size || tab_size > BME_MAX_TABLE_SIZE) {
return -EINVAL;
@@ -307,7 +308,7 @@ static int load_bitmap_data(BlockDriverState *bs,
buf = g_malloc(s->cluster_size);
sbc = sectors_covered_by_bitmap_cluster(s, bitmap);
for (i = 0, sector = 0; i < tab_size; ++i, sector += sbc) {
- uint64_t count = MIN(bm_size - sector, sbc);
+ uint64_t count = MIN(bm_sectors - sector, sbc);
uint64_t entry = bitmap_table[i];
uint64_t offset = entry & BME_TABLE_ENTRY_OFFSET_MASK;
@@ -1077,13 +1078,14 @@ static uint64_t *store_bitmap_data(BlockDriverState *bs,
int64_t sector;
uint64_t sbc;
uint64_t bm_size = bdrv_dirty_bitmap_size(bitmap);
+ uint64_t bm_sectors = DIV_ROUND_UP(bm_size, BDRV_SECTOR_SIZE);
const char *bm_name = bdrv_dirty_bitmap_name(bitmap);
uint8_t *buf = NULL;
BdrvDirtyBitmapIter *dbi;
uint64_t *tb;
uint64_t tb_size =
size_to_clusters(s,
- bdrv_dirty_bitmap_serialization_size(bitmap, 0, bm_size));
+ bdrv_dirty_bitmap_serialization_size(bitmap, 0, bm_sectors));
if (tb_size > BME_MAX_TABLE_SIZE ||
tb_size * s->cluster_size > BME_MAX_PHYS_SIZE)
@@ -1101,7 +1103,7 @@ static uint64_t *store_bitmap_data(BlockDriverState *bs,
dbi = bdrv_dirty_iter_new(bitmap, 0);
buf = g_malloc(s->cluster_size);
sbc = sectors_covered_by_bitmap_cluster(s, bitmap);
- assert(DIV_ROUND_UP(bm_size, sbc) == tb_size);
+ assert(DIV_ROUND_UP(bm_sectors, sbc) == tb_size);
while ((sector = bdrv_dirty_iter_next(dbi)) != -1) {
uint64_t cluster = sector / sbc;
@@ -1109,7 +1111,7 @@ static uint64_t *store_bitmap_data(BlockDriverState *bs,
int64_t off;
sector = cluster * sbc;
- end = MIN(bm_size, sector + sbc);
+ end = MIN(bm_sectors, sector + sbc);
write_size =
bdrv_dirty_bitmap_serialization_size(bitmap, sector, end - sector);
assert(write_size <= s->cluster_size);
@@ -1141,7 +1143,7 @@ static uint64_t *store_bitmap_data(BlockDriverState *bs,
goto fail;
}
- if (end >= bm_size) {
+ if (end >= bm_sectors) {
break;
}
--
2.13.5
