| Message ID | 20240513063203.113911-9-andrey.drobyshev@virtuozzo.com |
|---|---|
| State | New |
| Headers | show |
| Series | qcow2: make subclusters discardable | expand |
On 5/13/24 08:32, Andrey Drobyshev wrote: > When zeroizing the last non-zero subclusters within single cluster, it > makes sense to go zeroize the entire cluster and go down zero_in_l2_slice() > path right away. That way we'd also update the corresponding refcount > table. > > Signed-off-by: Andrey Drobyshev <andrey.drobyshev@virtuozzo.com> > Reviewed-by: Hanna Czenczek <hreitz@redhat.com> > --- > block/qcow2-cluster.c | 17 ++++++++++++++--- > 1 file changed, 14 insertions(+), 3 deletions(-) > > diff --git a/block/qcow2-cluster.c b/block/qcow2-cluster.c > index 475f167035..8d39e2f960 100644 > --- a/block/qcow2-cluster.c > +++ b/block/qcow2-cluster.c > @@ -2221,7 +2221,7 @@ zero_in_l2_slice(BlockDriverState *bs, uint64_t offset, > > static int coroutine_fn GRAPH_RDLOCK > zero_l2_subclusters(BlockDriverState *bs, uint64_t offset, > - unsigned nb_subclusters) > + unsigned nb_subclusters, int flags) > { > BDRVQcow2State *s = bs->opaque; > uint64_t new_l2_bitmap; > @@ -2237,6 +2237,16 @@ zero_l2_subclusters(BlockDriverState *bs, uint64_t offset, > 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 there're no non-zero subclusters left, we might as well zeroize > + * the entire cluster. That way we'd also update the refcount table. > + */ > + if ((new_l2_bitmap & QCOW_L2_BITMAP_ALL_ZEROES) == > + QCOW_L2_BITMAP_ALL_ZEROES) { > + return zero_in_l2_slice(bs, QEMU_ALIGN_DOWN(offset, s->cluster_size), > + 1, flags); > + } > + > 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); > @@ -2293,7 +2303,7 @@ int coroutine_fn qcow2_subcluster_zeroize(BlockDriverState *bs, uint64_t offset, > > if (head) { > ret = zero_l2_subclusters(bs, offset - head, > - size_to_subclusters(s, head)); > + size_to_subclusters(s, head), flags); > if (ret < 0) { > goto fail; > } > @@ -2314,7 +2324,8 @@ int coroutine_fn qcow2_subcluster_zeroize(BlockDriverState *bs, uint64_t offset, > } > > if (tail) { > - ret = zero_l2_subclusters(bs, end_offset, size_to_subclusters(s, tail)); > + ret = zero_l2_subclusters(bs, end_offset, > + size_to_subclusters(s, tail), flags); > if (ret < 0) { > goto fail; > } Reviewed-by: Alexander Ivanov <alexander.ivanov@virtuozzo.com>
diff --git a/block/qcow2-cluster.c b/block/qcow2-cluster.c index 475f167035..8d39e2f960 100644 --- a/block/qcow2-cluster.c +++ b/block/qcow2-cluster.c @@ -2221,7 +2221,7 @@ zero_in_l2_slice(BlockDriverState *bs, uint64_t offset, static int coroutine_fn GRAPH_RDLOCK zero_l2_subclusters(BlockDriverState *bs, uint64_t offset, - unsigned nb_subclusters) + unsigned nb_subclusters, int flags) { BDRVQcow2State *s = bs->opaque; uint64_t new_l2_bitmap; @@ -2237,6 +2237,16 @@ zero_l2_subclusters(BlockDriverState *bs, uint64_t offset, 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 there're no non-zero subclusters left, we might as well zeroize + * the entire cluster. That way we'd also update the refcount table. + */ + if ((new_l2_bitmap & QCOW_L2_BITMAP_ALL_ZEROES) == + QCOW_L2_BITMAP_ALL_ZEROES) { + return zero_in_l2_slice(bs, QEMU_ALIGN_DOWN(offset, s->cluster_size), + 1, flags); + } + 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); @@ -2293,7 +2303,7 @@ int coroutine_fn qcow2_subcluster_zeroize(BlockDriverState *bs, uint64_t offset, if (head) { ret = zero_l2_subclusters(bs, offset - head, - size_to_subclusters(s, head)); + size_to_subclusters(s, head), flags); if (ret < 0) { goto fail; } @@ -2314,7 +2324,8 @@ int coroutine_fn qcow2_subcluster_zeroize(BlockDriverState *bs, uint64_t offset, } if (tail) { - ret = zero_l2_subclusters(bs, end_offset, size_to_subclusters(s, tail)); + ret = zero_l2_subclusters(bs, end_offset, + size_to_subclusters(s, tail), flags); if (ret < 0) { goto fail; }