diff options
| -rw-r--r-- | block/qcow2-cluster.c | 3 | ||||
| -rw-r--r-- | block/qcow2-refcount.c | 65 | ||||
| -rw-r--r-- | block/qcow2.h | 8 |
3 files changed, 52 insertions, 24 deletions
diff --git a/block/qcow2-cluster.c b/block/qcow2-cluster.c index ee50500a07..405329adb5 100644 --- a/block/qcow2-cluster.c +++ b/block/qcow2-cluster.c @@ -1707,7 +1707,8 @@ static int expand_zero_clusters_in_l1(BlockDriverState *bs, uint64_t *l1_table, /* For shared L2 tables, set the refcount accordingly (it is * already 1 and needs to be l2_refcount) */ ret = qcow2_update_cluster_refcount(bs, - offset >> s->cluster_bits, l2_refcount - 1, + offset >> s->cluster_bits, + refcount_diff(1, l2_refcount), false, QCOW2_DISCARD_OTHER); if (ret < 0) { qcow2_free_clusters(bs, offset, s->cluster_size, diff --git a/block/qcow2-refcount.c b/block/qcow2-refcount.c index d8534903c3..354a355acf 100644 --- a/block/qcow2-refcount.c +++ b/block/qcow2-refcount.c @@ -29,8 +29,8 @@ static int64_t alloc_clusters_noref(BlockDriverState *bs, uint64_t size); static int QEMU_WARN_UNUSED_RESULT update_refcount(BlockDriverState *bs, - int64_t offset, int64_t length, - int addend, enum qcow2_discard_type type); + int64_t offset, int64_t length, uint16_t addend, + bool decrease, enum qcow2_discard_type type); /*********************************************************/ @@ -263,7 +263,7 @@ static int alloc_refcount_block(BlockDriverState *bs, } else { /* Described somewhere else. This can recurse at most twice before we * arrive at a block that describes itself. */ - ret = update_refcount(bs, new_block, s->cluster_size, 1, + ret = update_refcount(bs, new_block, s->cluster_size, 1, false, QCOW2_DISCARD_NEVER); if (ret < 0) { goto fail_block; @@ -530,8 +530,14 @@ found: } /* XXX: cache several refcount block clusters ? */ +/* @addend is the absolute value of the addend; if @decrease is set, @addend + * will be subtracted from the current refcount, otherwise it will be added */ static int QEMU_WARN_UNUSED_RESULT update_refcount(BlockDriverState *bs, - int64_t offset, int64_t length, int addend, enum qcow2_discard_type type) + int64_t offset, + int64_t length, + uint16_t addend, + bool decrease, + enum qcow2_discard_type type) { BDRVQcowState *s = bs->opaque; int64_t start, last, cluster_offset; @@ -540,8 +546,9 @@ static int QEMU_WARN_UNUSED_RESULT update_refcount(BlockDriverState *bs, int ret; #ifdef DEBUG_ALLOC2 - fprintf(stderr, "update_refcount: offset=%" PRId64 " size=%" PRId64 " addend=%d\n", - offset, length, addend); + fprintf(stderr, "update_refcount: offset=%" PRId64 " size=%" PRId64 + " addend=%s%" PRIu16 "\n", offset, length, decrease ? "-" : "", + addend); #endif if (length < 0) { return -EINVAL; @@ -549,7 +556,7 @@ static int QEMU_WARN_UNUSED_RESULT update_refcount(BlockDriverState *bs, return 0; } - if (addend < 0) { + if (decrease) { qcow2_cache_set_dependency(bs, s->refcount_block_cache, s->l2_table_cache); } @@ -559,7 +566,8 @@ static int QEMU_WARN_UNUSED_RESULT update_refcount(BlockDriverState *bs, for(cluster_offset = start; cluster_offset <= last; cluster_offset += s->cluster_size) { - int block_index, refcount; + int block_index; + uint16_t refcount; int64_t cluster_index = cluster_offset >> s->cluster_bits; int64_t table_index = cluster_index >> s->refcount_block_bits; @@ -586,11 +594,18 @@ static int QEMU_WARN_UNUSED_RESULT update_refcount(BlockDriverState *bs, block_index = cluster_index & (s->refcount_block_size - 1); refcount = be16_to_cpu(refcount_block[block_index]); - refcount += addend; - if (refcount < 0 || refcount > s->refcount_max) { + if (decrease ? ((uint16_t)(refcount - addend) > refcount) + : ((uint16_t)(refcount + addend) < refcount || + (uint16_t)(refcount + addend) > s->refcount_max)) + { ret = -EINVAL; goto fail; } + if (decrease) { + refcount -= addend; + } else { + refcount += addend; + } if (refcount == 0 && cluster_index < s->free_cluster_index) { s->free_cluster_index = cluster_index; } @@ -623,8 +638,8 @@ fail: */ if (ret < 0) { int dummy; - dummy = update_refcount(bs, offset, cluster_offset - offset, -addend, - QCOW2_DISCARD_NEVER); + dummy = update_refcount(bs, offset, cluster_offset - offset, addend, + !decrease, QCOW2_DISCARD_NEVER); (void)dummy; } @@ -634,18 +649,21 @@ fail: /* * Increases or decreases the refcount of a given cluster. * + * @addend is the absolute value of the addend; if @decrease is set, @addend + * will be subtracted from the current refcount, otherwise it will be added. + * * On success 0 is returned; on failure -errno is returned. */ int qcow2_update_cluster_refcount(BlockDriverState *bs, int64_t cluster_index, - int addend, + uint16_t addend, bool decrease, enum qcow2_discard_type type) { BDRVQcowState *s = bs->opaque; int ret; ret = update_refcount(bs, cluster_index << s->cluster_bits, 1, addend, - type); + decrease, type); if (ret < 0) { return ret; } @@ -709,7 +727,7 @@ int64_t qcow2_alloc_clusters(BlockDriverState *bs, uint64_t size) return offset; } - ret = update_refcount(bs, offset, size, 1, QCOW2_DISCARD_NEVER); + ret = update_refcount(bs, offset, size, 1, false, QCOW2_DISCARD_NEVER); } while (ret == -EAGAIN); if (ret < 0) { @@ -746,7 +764,7 @@ int qcow2_alloc_clusters_at(BlockDriverState *bs, uint64_t offset, } /* And then allocate them */ - ret = update_refcount(bs, offset, i << s->cluster_bits, 1, + ret = update_refcount(bs, offset, i << s->cluster_bits, 1, false, QCOW2_DISCARD_NEVER); } while (ret == -EAGAIN); @@ -797,7 +815,7 @@ int64_t qcow2_alloc_bytes(BlockDriverState *bs, int size) } assert(offset); - ret = update_refcount(bs, offset, size, 1, QCOW2_DISCARD_NEVER); + ret = update_refcount(bs, offset, size, 1, false, QCOW2_DISCARD_NEVER); if (ret < 0) { return ret; } @@ -821,7 +839,7 @@ void qcow2_free_clusters(BlockDriverState *bs, int ret; BLKDBG_EVENT(bs->file, BLKDBG_CLUSTER_FREE); - ret = update_refcount(bs, offset, size, -1, type); + ret = update_refcount(bs, offset, size, 1, true, type); if (ret < 0) { fprintf(stderr, "qcow2_free_clusters failed: %s\n", strerror(-ret)); /* TODO Remember the clusters to free them later and avoid leaking */ @@ -887,6 +905,8 @@ int qcow2_update_snapshot_refcount(BlockDriverState *bs, uint16_t refcount; int ret; + assert(addend >= -1 && addend <= 1); + l2_table = NULL; l1_table = NULL; l1_size2 = l1_size * sizeof(uint64_t); @@ -951,7 +971,7 @@ int qcow2_update_snapshot_refcount(BlockDriverState *bs, if (addend != 0) { ret = update_refcount(bs, (offset & s->cluster_offset_mask) & ~511, - nb_csectors * 512, addend, + nb_csectors * 512, abs(addend), addend < 0, QCOW2_DISCARD_SNAPSHOT); if (ret < 0) { goto fail; @@ -982,7 +1002,7 @@ int qcow2_update_snapshot_refcount(BlockDriverState *bs, } if (addend != 0) { ret = qcow2_update_cluster_refcount(bs, - cluster_index, addend, + cluster_index, abs(addend), addend < 0, QCOW2_DISCARD_SNAPSHOT); if (ret < 0) { goto fail; @@ -1025,7 +1045,7 @@ int qcow2_update_snapshot_refcount(BlockDriverState *bs, if (addend != 0) { ret = qcow2_update_cluster_refcount(bs, l2_offset >> s->cluster_bits, - addend, + abs(addend), addend < 0, QCOW2_DISCARD_SNAPSHOT); if (ret < 0) { goto fail; @@ -1678,7 +1698,8 @@ static void compare_refcounts(BlockDriverState *bs, BdrvCheckResult *res, if (num_fixed) { ret = update_refcount(bs, i << s->cluster_bits, 1, - (int)refcount2 - (int)refcount1, + refcount_diff(refcount1, refcount2), + refcount1 > refcount2, QCOW2_DISCARD_ALWAYS); if (ret >= 0) { (*num_fixed)++; diff --git a/block/qcow2.h b/block/qcow2.h index a33431f05a..40910d817d 100644 --- a/block/qcow2.h +++ b/block/qcow2.h @@ -459,6 +459,11 @@ static inline uint64_t l2meta_cow_end(QCowL2Meta *m) + (m->cow_end.nb_sectors << BDRV_SECTOR_BITS); } +static inline uint16_t refcount_diff(uint16_t r1, uint16_t r2) +{ + return r1 > r2 ? r1 - r2 : r2 - r1; +} + // FIXME Need qcow2_ prefix to global functions /* qcow2.c functions */ @@ -482,7 +487,8 @@ int qcow2_get_refcount(BlockDriverState *bs, int64_t cluster_index, uint16_t *refcount); int qcow2_update_cluster_refcount(BlockDriverState *bs, int64_t cluster_index, - int addend, enum qcow2_discard_type type); + uint16_t addend, bool decrease, + enum qcow2_discard_type type); int64_t qcow2_alloc_clusters(BlockDriverState *bs, uint64_t size); int qcow2_alloc_clusters_at(BlockDriverState *bs, uint64_t offset, |