Re: [Qemu-block] [PATCH v5 15/21] block: Resize bitmaps on bdrv_truncate
On 09.04.2015 00:19, John Snow wrote:
Signed-off-by: John Snow js...@redhat.com
---
block.c| 18 ++
include/qemu/hbitmap.h | 10 ++
util/hbitmap.c | 48
3 files changed, 76 insertions(+)
diff --git a/block.c b/block.c
index 16209a2..42839a0 100644
--- a/block.c
+++ b/block.c
@@ -113,6 +113,7 @@ static void bdrv_set_dirty(BlockDriverState *bs, int64_t
cur_sector,
int nr_sectors);
static void bdrv_reset_dirty(BlockDriverState *bs, int64_t cur_sector,
int nr_sectors);
+static void bdrv_dirty_bitmap_truncate(BlockDriverState *bs);
/* If non-zero, use only whitelisted block drivers */
static int use_bdrv_whitelist;
@@ -3583,6 +3584,7 @@ int bdrv_truncate(BlockDriverState *bs, int64_t offset)
ret = drv-bdrv_truncate(bs, offset);
if (ret == 0) {
ret = refresh_total_sectors(bs, offset BDRV_SECTOR_BITS);
+bdrv_dirty_bitmap_truncate(bs);
if (bs-blk) {
blk_dev_resize_cb(bs-blk);
}
@@ -5593,6 +5595,22 @@ BdrvDirtyBitmap
*bdrv_reclaim_dirty_bitmap(BlockDriverState *bs,
return parent;
}
+/**
+ * Truncates _all_ bitmaps attached to a BDS.
+ */
+static void bdrv_dirty_bitmap_truncate(BlockDriverState *bs)
+{
+BdrvDirtyBitmap *bitmap;
+uint64_t size = bdrv_nb_sectors(bs);
+
+QLIST_FOREACH(bitmap, bs-dirty_bitmaps, list) {
+if (bdrv_dirty_bitmap_frozen(bitmap)) {
+continue;
+}
+hbitmap_truncate(bitmap-bitmap, size);
+}
+}
+
void bdrv_release_dirty_bitmap(BlockDriverState *bs, BdrvDirtyBitmap *bitmap)
{
BdrvDirtyBitmap *bm, *next;
diff --git a/include/qemu/hbitmap.h b/include/qemu/hbitmap.h
index c19c1cb..a75157e 100644
--- a/include/qemu/hbitmap.h
+++ b/include/qemu/hbitmap.h
@@ -65,6 +65,16 @@ struct HBitmapIter {
HBitmap *hbitmap_alloc(uint64_t size, int granularity);
/**
+ * hbitmap_truncate:
+ * @hb: The bitmap to change the size of.
+ * @size: The number of elements to change the bitmap to accommodate.
+ *
+ * truncate or grow an existing bitmap to accommodate a new number of elements.
+ * This may invalidate existing HBitmapIterators.
+ */
+void hbitmap_truncate(HBitmap *hb, uint64_t size);
+
+/**
* hbitmap_merge:
* @a: The bitmap to store the result in.
* @b: The bitmap to merge into @a.
diff --git a/util/hbitmap.c b/util/hbitmap.c
index ba11fd3..1ad3bf3 100644
--- a/util/hbitmap.c
+++ b/util/hbitmap.c
@@ -400,6 +400,54 @@ HBitmap *hbitmap_alloc(uint64_t size, int granularity)
return hb;
}
+void hbitmap_truncate(HBitmap *hb, uint64_t size)
+{
+bool shrink;
+unsigned i;
+uint64_t num_elements = size;
+uint64_t old;
+
+/* Size comes in as logical elements, adjust for granularity. */
+size = (size + (1ULL hb-granularity) - 1) hb-granularity;
+assert(size = ((uint64_t)1 HBITMAP_LOG_MAX_SIZE));
+shrink = size hb-size;
+
+/* bit sizes are identical; nothing to do. */
+if (size == hb-size) {
+return;
+}
+
+/* If we're losing bits, let's clear those bits before we invalidate all of
+ * our invariants. This helps keep the bitcount consistent, and will
prevent
+ * us from carrying around garbage bits beyond the end of the map.
+ */
+if (shrink) {
+/* Don't clear partial granularity groups;
+ * start at the first full one. */
+uint64_t start = QEMU_ALIGN_UP(num_elements, 1 hb-granularity);
+uint64_t fix_count = (hb-size hb-granularity) - num_elements;
Shouldn't this be s/num_elements/start/?
Max
+
+assert(fix_count);
+hbitmap_reset(hb, start, fix_count);
+}
+
+hb-size = size;
+for (i = HBITMAP_LEVELS; i-- 0; ) {
+size = MAX(BITS_TO_LONGS(size), 1);
+if (hb-sizes[i] == size) {
+break;
+}
+old = hb-sizes[i];
+hb-sizes[i] = size;
+hb-levels[i] = g_realloc(hb-levels[i], size * sizeof(unsigned long));
+if (!shrink) {
+memset(hb-levels[i][old], 0x00,
+ (size - old) * sizeof(*hb-levels[i]));
+}
+}
+}
+
+
/**
* Given HBitmaps A and B, let A := A (BITOR) B.
* Bitmap B will not be modified.
[Qemu-block] [PATCH v5 15/21] block: Resize bitmaps on bdrv_truncate
Signed-off-by: John Snow js...@redhat.com
---
block.c| 18 ++
include/qemu/hbitmap.h | 10 ++
util/hbitmap.c | 48
3 files changed, 76 insertions(+)
diff --git a/block.c b/block.c
index 16209a2..42839a0 100644
--- a/block.c
+++ b/block.c
@@ -113,6 +113,7 @@ static void bdrv_set_dirty(BlockDriverState *bs, int64_t
cur_sector,
int nr_sectors);
static void bdrv_reset_dirty(BlockDriverState *bs, int64_t cur_sector,
int nr_sectors);
+static void bdrv_dirty_bitmap_truncate(BlockDriverState *bs);
/* If non-zero, use only whitelisted block drivers */
static int use_bdrv_whitelist;
@@ -3583,6 +3584,7 @@ int bdrv_truncate(BlockDriverState *bs, int64_t offset)
ret = drv-bdrv_truncate(bs, offset);
if (ret == 0) {
ret = refresh_total_sectors(bs, offset BDRV_SECTOR_BITS);
+bdrv_dirty_bitmap_truncate(bs);
if (bs-blk) {
blk_dev_resize_cb(bs-blk);
}
@@ -5593,6 +5595,22 @@ BdrvDirtyBitmap
*bdrv_reclaim_dirty_bitmap(BlockDriverState *bs,
return parent;
}
+/**
+ * Truncates _all_ bitmaps attached to a BDS.
+ */
+static void bdrv_dirty_bitmap_truncate(BlockDriverState *bs)
+{
+BdrvDirtyBitmap *bitmap;
+uint64_t size = bdrv_nb_sectors(bs);
+
+QLIST_FOREACH(bitmap, bs-dirty_bitmaps, list) {
+if (bdrv_dirty_bitmap_frozen(bitmap)) {
+continue;
+}
+hbitmap_truncate(bitmap-bitmap, size);
+}
+}
+
void bdrv_release_dirty_bitmap(BlockDriverState *bs, BdrvDirtyBitmap *bitmap)
{
BdrvDirtyBitmap *bm, *next;
diff --git a/include/qemu/hbitmap.h b/include/qemu/hbitmap.h
index c19c1cb..a75157e 100644
--- a/include/qemu/hbitmap.h
+++ b/include/qemu/hbitmap.h
@@ -65,6 +65,16 @@ struct HBitmapIter {
HBitmap *hbitmap_alloc(uint64_t size, int granularity);
/**
+ * hbitmap_truncate:
+ * @hb: The bitmap to change the size of.
+ * @size: The number of elements to change the bitmap to accommodate.
+ *
+ * truncate or grow an existing bitmap to accommodate a new number of elements.
+ * This may invalidate existing HBitmapIterators.
+ */
+void hbitmap_truncate(HBitmap *hb, uint64_t size);
+
+/**
* hbitmap_merge:
* @a: The bitmap to store the result in.
* @b: The bitmap to merge into @a.
diff --git a/util/hbitmap.c b/util/hbitmap.c
index ba11fd3..1ad3bf3 100644
--- a/util/hbitmap.c
+++ b/util/hbitmap.c
@@ -400,6 +400,54 @@ HBitmap *hbitmap_alloc(uint64_t size, int granularity)
return hb;
}
+void hbitmap_truncate(HBitmap *hb, uint64_t size)
+{
+bool shrink;
+unsigned i;
+uint64_t num_elements = size;
+uint64_t old;
+
+/* Size comes in as logical elements, adjust for granularity. */
+size = (size + (1ULL hb-granularity) - 1) hb-granularity;
+assert(size = ((uint64_t)1 HBITMAP_LOG_MAX_SIZE));
+shrink = size hb-size;
+
+/* bit sizes are identical; nothing to do. */
+if (size == hb-size) {
+return;
+}
+
+/* If we're losing bits, let's clear those bits before we invalidate all of
+ * our invariants. This helps keep the bitcount consistent, and will
prevent
+ * us from carrying around garbage bits beyond the end of the map.
+ */
+if (shrink) {
+/* Don't clear partial granularity groups;
+ * start at the first full one. */
+uint64_t start = QEMU_ALIGN_UP(num_elements, 1 hb-granularity);
+uint64_t fix_count = (hb-size hb-granularity) - num_elements;
+
+assert(fix_count);
+hbitmap_reset(hb, start, fix_count);
+}
+
+hb-size = size;
+for (i = HBITMAP_LEVELS; i-- 0; ) {
+size = MAX(BITS_TO_LONGS(size), 1);
+if (hb-sizes[i] == size) {
+break;
+}
+old = hb-sizes[i];
+hb-sizes[i] = size;
+hb-levels[i] = g_realloc(hb-levels[i], size * sizeof(unsigned long));
+if (!shrink) {
+memset(hb-levels[i][old], 0x00,
+ (size - old) * sizeof(*hb-levels[i]));
+}
+}
+}
+
+
/**
* Given HBitmaps A and B, let A := A (BITOR) B.
* Bitmap B will not be modified.
--
2.1.0
