diff options
| -rw-r--r-- | block/qcow2-cluster.c | 41 | ||||
| -rw-r--r-- | block/qcow2.c | 17 | ||||
| -rw-r--r-- | block/qcow2.h | 21 |
3 files changed, 60 insertions, 19 deletions
diff --git a/block/qcow2-cluster.c b/block/qcow2-cluster.c index dcf70a24d3..c8c85d224a 100644 --- a/block/qcow2-cluster.c +++ b/block/qcow2-cluster.c @@ -367,11 +367,9 @@ out: * * on exit, *num is the number of contiguous sectors we can read. * - * Return 0, if the offset is found - * Return -errno, otherwise. - * + * Returns the cluster type (QCOW2_CLUSTER_*) on success, -errno in error + * cases. */ - int qcow2_get_cluster_offset(BlockDriverState *bs, uint64_t offset, int *num, uint64_t *cluster_offset) { @@ -407,19 +405,19 @@ int qcow2_get_cluster_offset(BlockDriverState *bs, uint64_t offset, /* seek the the l2 offset in the l1 table */ l1_index = offset >> l1_bits; - if (l1_index >= s->l1_size) + if (l1_index >= s->l1_size) { + ret = QCOW2_CLUSTER_UNALLOCATED; goto out; + } - l2_offset = s->l1_table[l1_index]; - - /* seek the l2 table of the given l2 offset */ - - if (!l2_offset) + l2_offset = s->l1_table[l1_index] & L1E_OFFSET_MASK; + if (!l2_offset) { + ret = QCOW2_CLUSTER_UNALLOCATED; goto out; + } /* load the l2 table in memory */ - l2_offset &= ~QCOW_OFLAG_COPIED; ret = l2_load(bs, l2_offset, &l2_table); if (ret < 0) { return ret; @@ -431,26 +429,37 @@ int qcow2_get_cluster_offset(BlockDriverState *bs, uint64_t offset, *cluster_offset = be64_to_cpu(l2_table[l2_index]); nb_clusters = size_to_clusters(s, nb_needed << 9); - if (!*cluster_offset) { + ret = qcow2_get_cluster_type(*cluster_offset); + switch (ret) { + case QCOW2_CLUSTER_COMPRESSED: + /* Compressed clusters can only be processed one by one */ + c = 1; + *cluster_offset &= L2E_COMPRESSED_OFFSET_SIZE_MASK; + break; + case QCOW2_CLUSTER_UNALLOCATED: /* how many empty clusters ? */ c = count_contiguous_free_clusters(nb_clusters, &l2_table[l2_index]); - } else { + *cluster_offset = 0; + break; + case QCOW2_CLUSTER_NORMAL: /* how many allocated clusters ? */ c = count_contiguous_clusters(nb_clusters, s->cluster_size, &l2_table[l2_index], 0, QCOW_OFLAG_COPIED); + *cluster_offset &= L2E_OFFSET_MASK; + break; } qcow2_cache_put(bs, s->l2_table_cache, (void**) &l2_table); - nb_available = (c * s->cluster_sectors); + nb_available = (c * s->cluster_sectors); + out: if (nb_available > nb_needed) nb_available = nb_needed; *num = nb_available - index_in_cluster; - *cluster_offset &=~QCOW_OFLAG_COPIED; - return 0; + return ret; } /* diff --git a/block/qcow2.c b/block/qcow2.c index 70d3141dd1..4c82adc96f 100644 --- a/block/qcow2.c +++ b/block/qcow2.c @@ -449,7 +449,8 @@ static coroutine_fn int qcow2_co_readv(BlockDriverState *bs, int64_t sector_num, qemu_iovec_copy(&hd_qiov, qiov, bytes_done, cur_nr_sectors * 512); - if (!cluster_offset) { + switch (ret) { + case QCOW2_CLUSTER_UNALLOCATED: if (bs->backing_hd) { /* read from the base image */ @@ -469,7 +470,9 @@ static coroutine_fn int qcow2_co_readv(BlockDriverState *bs, int64_t sector_num, /* Note: in this case, no need to wait */ qemu_iovec_memset(&hd_qiov, 0, 512 * cur_nr_sectors); } - } else if (cluster_offset & QCOW_OFLAG_COMPRESSED) { + break; + + case QCOW2_CLUSTER_COMPRESSED: /* add AIO support for compressed blocks ? */ ret = qcow2_decompress_cluster(bs, cluster_offset); if (ret < 0) { @@ -479,7 +482,9 @@ static coroutine_fn int qcow2_co_readv(BlockDriverState *bs, int64_t sector_num, qemu_iovec_from_buffer(&hd_qiov, s->cluster_cache + index_in_cluster * 512, 512 * cur_nr_sectors); - } else { + break; + + case QCOW2_CLUSTER_NORMAL: if ((cluster_offset & 511) != 0) { ret = -EIO; goto fail; @@ -520,6 +525,12 @@ static coroutine_fn int qcow2_co_readv(BlockDriverState *bs, int64_t sector_num, qemu_iovec_from_buffer(&hd_qiov, cluster_data, 512 * cur_nr_sectors); } + break; + + default: + g_assert_not_reached(); + ret = -EIO; + goto fail; } remaining_sectors -= cur_nr_sectors; diff --git a/block/qcow2.h b/block/qcow2.h index ddb976a759..a22d7fafbe 100644 --- a/block/qcow2.h +++ b/block/qcow2.h @@ -165,6 +165,16 @@ typedef struct QCowL2Meta QLIST_ENTRY(QCowL2Meta) next_in_flight; } QCowL2Meta; +enum { + QCOW2_CLUSTER_UNALLOCATED, + QCOW2_CLUSTER_NORMAL, + QCOW2_CLUSTER_COMPRESSED, +}; + +#define L1E_OFFSET_MASK 0x00ffffffffffff00ULL +#define L2E_OFFSET_MASK 0x00ffffffffffff00ULL +#define L2E_COMPRESSED_OFFSET_SIZE_MASK 0x3fffffffffffffffULL + static inline int size_to_clusters(BDRVQcowState *s, int64_t size) { return (size + (s->cluster_size - 1)) >> s->cluster_bits; @@ -182,6 +192,17 @@ static inline int64_t align_offset(int64_t offset, int n) return offset; } +static inline int qcow2_get_cluster_type(uint64_t l2_entry) +{ + if (l2_entry & QCOW_OFLAG_COMPRESSED) { + return QCOW2_CLUSTER_COMPRESSED; + } else if (!(l2_entry & L2E_OFFSET_MASK)) { + return QCOW2_CLUSTER_UNALLOCATED; + } else { + return QCOW2_CLUSTER_NORMAL; + } +} + // FIXME Need qcow2_ prefix to global functions |