From a6e098462ba6d8585a6f21729b406ab51a70eb03 Mon Sep 17 00:00:00 2001 From: Vladimir Sementsov-Ogievskiy Date: Tue, 14 Sep 2021 15:24:47 +0300 Subject: [PATCH] qcow2: introduce qcow2_parse_compressed_l2_entry() helper Add helper to parse compressed l2_entry and use it everywhere instead of open-coding. Note, that in most places we move to precise coffset/csize instead of sector-aligned. Still it should work good enough for updating refcounts. Signed-off-by: Vladimir Sementsov-Ogievskiy Reviewed-by: Eric Blake Reviewed-by: Hanna Reitz Message-Id: <20210914122454.141075-4-vsementsov@virtuozzo.com> Signed-off-by: Hanna Reitz --- block/qcow2-cluster.c | 15 +++++++++++++++ block/qcow2-refcount.c | 36 +++++++++++++++++------------------- block/qcow2.c | 9 ++------- block/qcow2.h | 3 ++- 4 files changed, 36 insertions(+), 27 deletions(-) diff --git a/block/qcow2-cluster.c b/block/qcow2-cluster.c index 3d53657c26..4ebb49a087 100644 --- a/block/qcow2-cluster.c +++ b/block/qcow2-cluster.c @@ -2480,3 +2480,18 @@ fail: g_free(l1_table); return ret; } + +void qcow2_parse_compressed_l2_entry(BlockDriverState *bs, uint64_t l2_entry, + uint64_t *coffset, int *csize) +{ + BDRVQcow2State *s = bs->opaque; + int nb_csectors; + + assert(qcow2_get_cluster_type(bs, l2_entry) == QCOW2_CLUSTER_COMPRESSED); + + *coffset = l2_entry & s->cluster_offset_mask; + + nb_csectors = ((l2_entry >> s->csize_shift) & s->csize_mask) + 1; + *csize = nb_csectors * QCOW2_COMPRESSED_SECTOR_SIZE - + (*coffset & (QCOW2_COMPRESSED_SECTOR_SIZE - 1)); +} diff --git a/block/qcow2-refcount.c b/block/qcow2-refcount.c index 2734338625..66cbb94ef9 100644 --- a/block/qcow2-refcount.c +++ b/block/qcow2-refcount.c @@ -1177,11 +1177,11 @@ void qcow2_free_any_cluster(BlockDriverState *bs, uint64_t l2_entry, switch (ctype) { case QCOW2_CLUSTER_COMPRESSED: { - int64_t offset = (l2_entry & s->cluster_offset_mask) - & QCOW2_COMPRESSED_SECTOR_MASK; - int size = QCOW2_COMPRESSED_SECTOR_SIZE * - (((l2_entry >> s->csize_shift) & s->csize_mask) + 1); - qcow2_free_clusters(bs, offset, size, type); + uint64_t coffset; + int csize; + + qcow2_parse_compressed_l2_entry(bs, l2_entry, &coffset, &csize); + qcow2_free_clusters(bs, coffset, csize, type); } break; case QCOW2_CLUSTER_NORMAL: @@ -1247,7 +1247,7 @@ int qcow2_update_snapshot_refcount(BlockDriverState *bs, bool l1_allocated = false; int64_t old_entry, old_l2_offset; unsigned slice, slice_size2, n_slices; - int i, j, l1_modified = 0, nb_csectors; + int i, j, l1_modified = 0; int ret; assert(addend >= -1 && addend <= 1); @@ -1318,14 +1318,14 @@ int qcow2_update_snapshot_refcount(BlockDriverState *bs, switch (qcow2_get_cluster_type(bs, entry)) { case QCOW2_CLUSTER_COMPRESSED: - nb_csectors = ((entry >> s->csize_shift) & - s->csize_mask) + 1; if (addend != 0) { - uint64_t coffset = (entry & s->cluster_offset_mask) - & QCOW2_COMPRESSED_SECTOR_MASK; + uint64_t coffset; + int csize; + + qcow2_parse_compressed_l2_entry(bs, entry, + &coffset, &csize); ret = update_refcount( - bs, coffset, - nb_csectors * QCOW2_COMPRESSED_SECTOR_SIZE, + bs, coffset, csize, abs(addend), addend < 0, QCOW2_DISCARD_SNAPSHOT); if (ret < 0) { @@ -1603,7 +1603,7 @@ static int check_refcounts_l2(BlockDriverState *bs, BdrvCheckResult *res, BDRVQcow2State *s = bs->opaque; uint64_t l2_entry; uint64_t next_contiguous_offset = 0; - int i, nb_csectors, ret; + int i, ret; size_t l2_size_bytes = s->l2_size * l2_entry_size(s); g_autofree uint64_t *l2_table = g_malloc(l2_size_bytes); @@ -1617,6 +1617,8 @@ static int check_refcounts_l2(BlockDriverState *bs, BdrvCheckResult *res, /* Do the actual checks */ for (i = 0; i < s->l2_size; i++) { + uint64_t coffset; + int csize; l2_entry = get_l2_entry(s, l2_table, i); switch (qcow2_get_cluster_type(bs, l2_entry)) { @@ -1638,13 +1640,9 @@ static int check_refcounts_l2(BlockDriverState *bs, BdrvCheckResult *res, } /* Mark cluster as used */ - nb_csectors = ((l2_entry >> s->csize_shift) & - s->csize_mask) + 1; - l2_entry &= s->cluster_offset_mask; + qcow2_parse_compressed_l2_entry(bs, l2_entry, &coffset, &csize); ret = qcow2_inc_refcounts_imrt( - bs, res, refcount_table, refcount_table_size, - l2_entry & QCOW2_COMPRESSED_SECTOR_MASK, - nb_csectors * QCOW2_COMPRESSED_SECTOR_SIZE); + bs, res, refcount_table, refcount_table_size, coffset, csize); if (ret < 0) { return ret; } diff --git a/block/qcow2.c b/block/qcow2.c index e5d8ab679e..02f9f3e636 100644 --- a/block/qcow2.c +++ b/block/qcow2.c @@ -4700,17 +4700,12 @@ qcow2_co_preadv_compressed(BlockDriverState *bs, size_t qiov_offset) { BDRVQcow2State *s = bs->opaque; - int ret = 0, csize, nb_csectors; + int ret = 0, csize; uint64_t coffset; uint8_t *buf, *out_buf; int offset_in_cluster = offset_into_cluster(s, offset); - assert(qcow2_get_cluster_type(bs, l2_entry) == QCOW2_CLUSTER_COMPRESSED); - - coffset = l2_entry & s->cluster_offset_mask; - nb_csectors = ((l2_entry >> s->csize_shift) & s->csize_mask) + 1; - csize = nb_csectors * QCOW2_COMPRESSED_SECTOR_SIZE - - (coffset & ~QCOW2_COMPRESSED_SECTOR_MASK); + qcow2_parse_compressed_l2_entry(bs, l2_entry, &coffset, &csize); buf = g_try_malloc(csize); if (!buf) { diff --git a/block/qcow2.h b/block/qcow2.h index 42a0058ab7..c0e1e83796 100644 --- a/block/qcow2.h +++ b/block/qcow2.h @@ -110,7 +110,6 @@ /* Defined in the qcow2 spec (compressed cluster descriptor) */ #define QCOW2_COMPRESSED_SECTOR_SIZE 512U -#define QCOW2_COMPRESSED_SECTOR_MASK (~(QCOW2_COMPRESSED_SECTOR_SIZE - 1ULL)) /* Must be at least 2 to cover COW */ #define MIN_L2_CACHE_SIZE 2 /* cache entries */ @@ -913,6 +912,8 @@ int qcow2_alloc_compressed_cluster_offset(BlockDriverState *bs, uint64_t offset, int compressed_size, uint64_t *host_offset); +void qcow2_parse_compressed_l2_entry(BlockDriverState *bs, uint64_t l2_entry, + uint64_t *coffset, int *csize); int qcow2_alloc_cluster_link_l2(BlockDriverState *bs, QCowL2Meta *m); void qcow2_alloc_cluster_abort(BlockDriverState *bs, QCowL2Meta *m);