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block: implement dirty bitmap using HBitmap

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This actually uses the dirty bitmap in the block layer, and converts
mirroring to use an HBitmapIter.

Reviewed-by: Laszlo Ersek <lersek@redhat.com> (except block/mirror.c parts)
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This commit is contained in:
Paolo Bonzini 2013-01-21 17:09:41 +01:00 • committed by Kevin Wolf
parent e7c033c3fa
commit 8f0720ecbc
5 changed files with 33 additions and 86 deletions
Download patch file Download diff file Expand all files Collapse all files

96
block.c
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@ -1286,7 +1286,6 @@ static void bdrv_move_feature_fields(BlockDriverState *bs_dest,
bs_dest->iostatus = bs_src->iostatus;
/* dirty bitmap */
bs_dest->dirty_count = bs_src->dirty_count;
bs_dest->dirty_bitmap = bs_src->dirty_bitmap;
/* job */
@ -2035,36 +2034,6 @@ int bdrv_read_unthrottled(BlockDriverState *bs, int64_t sector_num,
return ret;
}
#define BITS_PER_LONG (sizeof(unsigned long) * 8)
static void set_dirty_bitmap(BlockDriverState *bs, int64_t sector_num,
int nb_sectors, int dirty)
{
int64_t start, end;
unsigned long val, idx, bit;
start = sector_num / BDRV_SECTORS_PER_DIRTY_CHUNK;
end = (sector_num + nb_sectors - 1) / BDRV_SECTORS_PER_DIRTY_CHUNK;
for (; start <= end; start++) {
idx = start / BITS_PER_LONG;
bit = start % BITS_PER_LONG;
val = bs->dirty_bitmap[idx];
if (dirty) {
if (!(val & (1UL << bit))) {
bs->dirty_count++;
val |= 1UL << bit;
}
} else {
if (val & (1UL << bit)) {
bs->dirty_count--;
val &= ~(1UL << bit);
}
}
bs->dirty_bitmap[idx] = val;
}
}
/* Return < 0 if error. Important errors are:
-EIO generic I/O error (may happen for all errors)
-ENOMEDIUM No media inserted.
@ -4173,7 +4142,7 @@ int coroutine_fn bdrv_co_discard(BlockDriverState *bs, int64_t sector_num,
}
if (bs->dirty_bitmap) {
set_dirty_bitmap(bs, sector_num, nb_sectors, 0);
bdrv_reset_dirty(bs, sector_num, nb_sectors);
}
if (bs->drv->bdrv_co_discard) {
@ -4335,18 +4304,15 @@ void bdrv_set_dirty_tracking(BlockDriverState *bs, int enable)
{
int64_t bitmap_size;
bs->dirty_count = 0;
if (enable) {
if (!bs->dirty_bitmap) {
bitmap_size = (bdrv_getlength(bs) >> BDRV_SECTOR_BITS) +
BDRV_SECTORS_PER_DIRTY_CHUNK * BITS_PER_LONG - 1;
bitmap_size /= BDRV_SECTORS_PER_DIRTY_CHUNK * BITS_PER_LONG;
bs->dirty_bitmap = g_new0(unsigned long, bitmap_size);
bitmap_size = (bdrv_getlength(bs) >> BDRV_SECTOR_BITS);
bs->dirty_bitmap = hbitmap_alloc(bitmap_size,
BDRV_LOG_SECTORS_PER_DIRTY_CHUNK);
}
} else {
if (bs->dirty_bitmap) {
g_free(bs->dirty_bitmap);
hbitmap_free(bs->dirty_bitmap);
bs->dirty_bitmap = NULL;
}
}
@ -4354,67 +4320,37 @@ void bdrv_set_dirty_tracking(BlockDriverState *bs, int enable)
int bdrv_get_dirty(BlockDriverState *bs, int64_t sector)
{
int64_t chunk = sector / (int64_t)BDRV_SECTORS_PER_DIRTY_CHUNK;
if (bs->dirty_bitmap &&
(sector << BDRV_SECTOR_BITS) < bdrv_getlength(bs)) {
return !!(bs->dirty_bitmap[chunk / BITS_PER_LONG] &
(1UL << (chunk % BITS_PER_LONG)));
if (bs->dirty_bitmap) {
return hbitmap_get(bs->dirty_bitmap, sector);
} else {
return 0;
}
}
int64_t bdrv_get_next_dirty(BlockDriverState *bs, int64_t sector)
void bdrv_dirty_iter_init(BlockDriverState *bs, HBitmapIter *hbi)
{
int64_t chunk;
int bit, elem;
/* Avoid an infinite loop. */
assert(bs->dirty_count > 0);
sector = (sector | (BDRV_SECTORS_PER_DIRTY_CHUNK - 1)) + 1;
chunk = sector / (int64_t)BDRV_SECTORS_PER_DIRTY_CHUNK;
QEMU_BUILD_BUG_ON(sizeof(bs->dirty_bitmap[0]) * 8 != BITS_PER_LONG);
elem = chunk / BITS_PER_LONG;
bit = chunk % BITS_PER_LONG;
for (;;) {
if (sector >= bs->total_sectors) {
sector = 0;
bit = elem = 0;
}
if (bit == 0 && bs->dirty_bitmap[elem] == 0) {
sector += BDRV_SECTORS_PER_DIRTY_CHUNK * BITS_PER_LONG;
elem++;
} else {
if (bs->dirty_bitmap[elem] & (1UL << bit)) {
return sector;
}
sector += BDRV_SECTORS_PER_DIRTY_CHUNK;
if (++bit == BITS_PER_LONG) {
bit = 0;
elem++;
}
}
}
hbitmap_iter_init(hbi, bs->dirty_bitmap, 0);
}
void bdrv_set_dirty(BlockDriverState *bs, int64_t cur_sector,
int nr_sectors)
{
set_dirty_bitmap(bs, cur_sector, nr_sectors, 1);
hbitmap_set(bs->dirty_bitmap, cur_sector, nr_sectors);
}
void bdrv_reset_dirty(BlockDriverState *bs, int64_t cur_sector,
int nr_sectors)
{
set_dirty_bitmap(bs, cur_sector, nr_sectors, 0);
hbitmap_reset(bs->dirty_bitmap, cur_sector, nr_sectors);
}
int64_t bdrv_get_dirty_count(BlockDriverState *bs)
{
return bs->dirty_count;
if (bs->dirty_bitmap) {
return hbitmap_count(bs->dirty_bitmap) >> BDRV_LOG_SECTORS_PER_DIRTY_CHUNK;
} else {
return 0;
}
}
void bdrv_set_in_use(BlockDriverState *bs, int in_use)