This helper simply obtains the l2 table parameters of the cluster which contains the given subclusters range. Right now this info is being obtained and used by zero_l2_subclusters(). As we're about to introduce the subclusters discard operation, this helper would let us avoid code duplication.
Also introduce struct SubClusterRangeInfo, which would contain all the needed params. Signed-off-by: Andrey Drobyshev <[email protected]> --- block/qcow2-cluster.c | 90 +++++++++++++++++++++++++++++-------------- 1 file changed, 62 insertions(+), 28 deletions(-) diff --git a/block/qcow2-cluster.c b/block/qcow2-cluster.c index 904f00d1b3..8801856b93 100644 --- a/block/qcow2-cluster.c +++ b/block/qcow2-cluster.c @@ -32,6 +32,13 @@ #include "qemu/memalign.h" #include "trace.h" +typedef struct SubClusterRangeInfo { + uint64_t *l2_slice; + int l2_index; + uint64_t l2_entry; + uint64_t l2_bitmap; +} SubClusterRangeInfo; + int coroutine_fn qcow2_shrink_l1_table(BlockDriverState *bs, uint64_t exact_size) { @@ -1892,6 +1899,50 @@ again: return 0; } +static int get_sc_range_info(BlockDriverState *bs, uint64_t offset, + unsigned nb_subclusters, + SubClusterRangeInfo *scri) +{ + BDRVQcow2State *s = bs->opaque; + int ret, sc_cleared = 0, sc_index = offset_to_sc_index(s, offset); + QCow2SubclusterType sctype; + + /* Here we only work with the subclusters within single cluster. */ + assert(nb_subclusters > 0 && nb_subclusters < s->subclusters_per_cluster); + assert(sc_index + nb_subclusters <= s->subclusters_per_cluster); + assert(offset_into_subcluster(s, offset) == 0); + + ret = get_cluster_table(bs, offset, &scri->l2_slice, &scri->l2_index); + if (ret < 0) { + return ret; + } + + scri->l2_entry = get_l2_entry(s, scri->l2_slice, scri->l2_index); + scri->l2_bitmap = get_l2_bitmap(s, scri->l2_slice, scri->l2_index); + + do { + qcow2_get_subcluster_range_type(bs, scri->l2_entry, scri->l2_bitmap, + sc_index, &sctype); + if (ret < 0) { + return ret; + } + + switch (sctype) { + case QCOW2_SUBCLUSTER_COMPRESSED: + /* We cannot partially zeroize/discard compressed clusters. */ + return -ENOTSUP; + case QCOW2_SUBCLUSTER_INVALID: + return -EINVAL; + default: + break; + } + + sc_cleared += ret; + } while (sc_cleared < nb_subclusters); + + return 0; +} + /* * This discards as many clusters of nb_clusters as possible at once (i.e. * all clusters in the same L2 slice) and returns the number of discarded @@ -2097,44 +2148,27 @@ zero_l2_subclusters(BlockDriverState *bs, uint64_t offset, unsigned nb_subclusters) { BDRVQcow2State *s = bs->opaque; - uint64_t *l2_slice; - uint64_t old_l2_bitmap, l2_bitmap; - int l2_index, ret, sc = offset_to_sc_index(s, offset); + uint64_t new_l2_bitmap; + int ret, sc = offset_to_sc_index(s, offset); + SubClusterRangeInfo scri = { 0 }; - /* For full clusters use zero_in_l2_slice() instead */ - assert(nb_subclusters > 0 && nb_subclusters < s->subclusters_per_cluster); - assert(sc + nb_subclusters <= s->subclusters_per_cluster); - assert(offset_into_subcluster(s, offset) == 0); - - ret = get_cluster_table(bs, offset, &l2_slice, &l2_index); + ret = get_sc_range_info(bs, offset, nb_subclusters, &scri); if (ret < 0) { - return ret; - } - - switch (qcow2_get_cluster_type(bs, get_l2_entry(s, l2_slice, l2_index))) { - case QCOW2_CLUSTER_COMPRESSED: - ret = -ENOTSUP; /* We cannot partially zeroize compressed clusters */ goto out; - case QCOW2_CLUSTER_NORMAL: - case QCOW2_CLUSTER_UNALLOCATED: - break; - default: - g_assert_not_reached(); } - old_l2_bitmap = l2_bitmap = get_l2_bitmap(s, l2_slice, l2_index); - - l2_bitmap |= QCOW_OFLAG_SUB_ZERO_RANGE(sc, sc + nb_subclusters); - l2_bitmap &= ~QCOW_OFLAG_SUB_ALLOC_RANGE(sc, sc + nb_subclusters); + new_l2_bitmap = scri.l2_bitmap; + new_l2_bitmap |= QCOW_OFLAG_SUB_ZERO_RANGE(sc, sc + nb_subclusters); + new_l2_bitmap &= ~QCOW_OFLAG_SUB_ALLOC_RANGE(sc, sc + nb_subclusters); - if (old_l2_bitmap != l2_bitmap) { - set_l2_bitmap(s, l2_slice, l2_index, l2_bitmap); - qcow2_cache_entry_mark_dirty(s->l2_table_cache, l2_slice); + if (new_l2_bitmap != scri.l2_bitmap) { + set_l2_bitmap(s, scri.l2_slice, scri.l2_index, new_l2_bitmap); + qcow2_cache_entry_mark_dirty(s->l2_table_cache, scri.l2_slice); } ret = 0; out: - qcow2_cache_put(s->l2_table_cache, (void **) &l2_slice); + qcow2_cache_put(s->l2_table_cache, (void **) &scri.l2_slice); return ret; } -- 2.39.3
