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qcow2: Fix discard

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discard_single_l2() should not implement its own version of
qcow2_get_cluster_type(), but rather rely on this already existing
function. By doing so, it will work for compressed clusters as well
(which it did not so far).

Also, rename "old_offset" to "old_l2_entry", as both are quite different
(and the value is indeed of the latter kind).

Signed-off-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This commit is contained in:
Max Reitz 2014-04-29 16:12:30 +02:00 committed by Kevin Wolf
parent cc8a7e560c
commit c883db0df9
1 changed files with 18 additions and 8 deletions
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26
block/qcow2-cluster.c
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@ -1360,9 +1360,9 @@ static int discard_single_l2(BlockDriverState *bs, uint64_t offset,
nb_clusters = MIN(nb_clusters, s->l2_size - l2_index); nb_clusters = MIN(nb_clusters, s->l2_size - l2_index);
for (i = 0; i < nb_clusters; i++) { for (i = 0; i < nb_clusters; i++) {
uint64_t old_offset; uint64_t old_l2_entry;
old_offset = be64_to_cpu(l2_table[l2_index + i]); old_l2_entry = be64_to_cpu(l2_table[l2_index + i]);
/* /*
* Make sure that a discarded area reads back as zeroes for v3 images * Make sure that a discarded area reads back as zeroes for v3 images
@ -1373,12 +1373,22 @@ static int discard_single_l2(BlockDriverState *bs, uint64_t offset,
* TODO We might want to use bdrv_get_block_status(bs) here, but we're * TODO We might want to use bdrv_get_block_status(bs) here, but we're
* holding s->lock, so that doesn't work today. * holding s->lock, so that doesn't work today.
*/ */
if (old_offset & QCOW_OFLAG_ZERO) { switch (qcow2_get_cluster_type(old_l2_entry)) {
continue; case QCOW2_CLUSTER_UNALLOCATED:
} if (!bs->backing_hd) {
continue;
}
break;
if ((old_offset & L2E_OFFSET_MASK) == 0 && !bs->backing_hd) { case QCOW2_CLUSTER_ZERO:
continue; continue;
case QCOW2_CLUSTER_NORMAL:
case QCOW2_CLUSTER_COMPRESSED:
break;
default:
abort();
} }
/* First remove L2 entries */ /* First remove L2 entries */
@ -1390,7 +1400,7 @@ static int discard_single_l2(BlockDriverState *bs, uint64_t offset,
} }
/* Then decrease the refcount */ /* Then decrease the refcount */
qcow2_free_any_clusters(bs, old_offset, 1, type); qcow2_free_any_clusters(bs, old_l2_entry, 1, type);
} }
ret = qcow2_cache_put(bs, s->l2_table_cache, (void**) &l2_table); ret = qcow2_cache_put(bs, s->l2_table_cache, (void**) &l2_table);