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update_refcount: Write complete sectors 

When updating the refcount blocks in update_refcount(), write complete sectors
instead of updating single entries.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
This commit is contained in:
Kevin Wolf 2009-06-16 11:31:30 +02:00 committed by Anthony Liguori
parent 4c1612d954
commit 9923e05e1a
1 changed files with 26 additions and 8 deletions
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34
block/qcow2-refcount.c
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@ -209,6 +209,27 @@ static int64_t alloc_refcount_block(BlockDriverState *bs, int64_t cluster_index)
return refcount_block_offset;
}
#define REFCOUNTS_PER_SECTOR (512 >> REFCOUNT_SHIFT)
static int write_refcount_block_entries(BDRVQcowState *s,
int64_t refcount_block_offset, int first_index, int last_index)
{
size_t size;
first_index &= ~(REFCOUNTS_PER_SECTOR - 1);
last_index = (last_index + REFCOUNTS_PER_SECTOR)
& ~(REFCOUNTS_PER_SECTOR - 1);
size = (last_index - first_index) << REFCOUNT_SHIFT;
if (bdrv_pwrite(s->hd,
refcount_block_offset + (first_index << REFCOUNT_SHIFT),
&s->refcount_block_cache[first_index], size) != size)
{
return -EIO;
}
return 0;
}
/* XXX: cache several refcount block clusters ? */
static int update_refcount(BlockDriverState *bs,
int64_t offset, int64_t length,
@ -238,10 +259,9 @@ static int update_refcount(BlockDriverState *bs,
old_table_index = table_index;
table_index = cluster_index >> (s->cluster_bits - REFCOUNT_SHIFT);
if ((old_table_index >= 0) && (table_index != old_table_index)) {
size_t size = (last_index - first_index + 1) << REFCOUNT_SHIFT;
if (bdrv_pwrite(s->hd,
refcount_block_offset + (first_index << REFCOUNT_SHIFT),
&s->refcount_block_cache[first_index], size) != size)
if (write_refcount_block_entries(s, refcount_block_offset,
first_index, last_index) < 0)
{
return -EIO;
}
@ -278,10 +298,8 @@ static int update_refcount(BlockDriverState *bs,
/* Write last changed block to disk */
if (refcount_block_offset != 0) {
size_t size = (last_index - first_index + 1) << REFCOUNT_SHIFT;
if (bdrv_pwrite(s->hd,
refcount_block_offset + (first_index << REFCOUNT_SHIFT),
&s->refcount_block_cache[first_index], size) != size)
if (write_refcount_block_entries(s, refcount_block_offset,
first_index, last_index) < 0)
{
return -EIO;
}