diff options
| -rw-r--r-- | block-qcow2.c | 162 |
1 files changed, 73 insertions, 89 deletions
diff --git a/block-qcow2.c b/block-qcow2.c index a65a10d69b..98c66f192d 100644 --- a/block-qcow2.c +++ b/block-qcow2.c @@ -601,6 +601,34 @@ static uint64_t *l2_allocate(BlockDriverState *bs, int l1_index) return l2_table; } +static int size_to_clusters(BDRVQcowState *s, int64_t size) +{ + return (size + (s->cluster_size - 1)) >> s->cluster_bits; +} + +static int count_contiguous_clusters(uint64_t nb_clusters, int cluster_size, + uint64_t *l2_table, uint64_t mask) +{ + int i; + uint64_t offset = be64_to_cpu(l2_table[0]) & ~mask; + + for (i = 0; i < nb_clusters; i++) + if (offset + i * cluster_size != (be64_to_cpu(l2_table[i]) & ~mask)) + break; + + return i; +} + +static int count_contiguous_free_clusters(uint64_t nb_clusters, uint64_t *l2_table) +{ + int i = 0; + + while(nb_clusters-- && l2_table[i] == 0) + i++; + + return i; +} + /* * get_cluster_offset * @@ -622,9 +650,9 @@ static uint64_t get_cluster_offset(BlockDriverState *bs, { BDRVQcowState *s = bs->opaque; int l1_index, l2_index; - uint64_t l2_offset, *l2_table, cluster_offset, next; - int l1_bits; - int index_in_cluster, nb_available, nb_needed; + uint64_t l2_offset, *l2_table, cluster_offset; + int l1_bits, c; + int index_in_cluster, nb_available, nb_needed, nb_clusters; index_in_cluster = (offset >> 9) & (s->cluster_sectors - 1); nb_needed = *num + index_in_cluster; @@ -632,7 +660,7 @@ static uint64_t get_cluster_offset(BlockDriverState *bs, l1_bits = s->l2_bits + s->cluster_bits; /* compute how many bytes there are between the offset and - * and the end of the l1 entry + * the end of the l1 entry */ nb_available = (1 << l1_bits) - (offset & ((1 << l1_bits) - 1)); @@ -667,38 +695,25 @@ static uint64_t get_cluster_offset(BlockDriverState *bs, l2_index = (offset >> s->cluster_bits) & (s->l2_size - 1); cluster_offset = be64_to_cpu(l2_table[l2_index]); - nb_available = s->cluster_sectors; - l2_index++; + nb_clusters = size_to_clusters(s, nb_needed << 9); if (!cluster_offset) { - - /* how many empty clusters ? */ - - while (nb_available < nb_needed && !l2_table[l2_index]) { - l2_index++; - nb_available += s->cluster_sectors; - } + /* how many empty clusters ? */ + c = count_contiguous_free_clusters(nb_clusters, &l2_table[l2_index]); } else { + /* how many allocated clusters ? */ + c = count_contiguous_clusters(nb_clusters, s->cluster_size, + &l2_table[l2_index], QCOW_OFLAG_COPIED); + } - /* how many allocated clusters ? */ - - cluster_offset &= ~QCOW_OFLAG_COPIED; - while (nb_available < nb_needed) { - next = be64_to_cpu(l2_table[l2_index]) & ~QCOW_OFLAG_COPIED; - if (next != cluster_offset + (nb_available << 9)) - break; - l2_index++; - nb_available += 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; - return cluster_offset; + return cluster_offset & ~QCOW_OFLAG_COPIED; } /* @@ -862,15 +877,15 @@ static uint64_t alloc_cluster_offset(BlockDriverState *bs, BDRVQcowState *s = bs->opaque; int l2_index, ret; uint64_t l2_offset, *l2_table, cluster_offset; - int nb_available, nb_clusters, i, j; - uint64_t start_sect, current; + int nb_available, nb_clusters, i = 0; + uint64_t start_sect; ret = get_cluster_table(bs, offset, &l2_table, &l2_offset, &l2_index); if (ret == 0) return 0; - nb_clusters = ((n_end << 9) + s->cluster_size - 1) >> - s->cluster_bits; + nb_clusters = size_to_clusters(s, n_end << 9); + if (nb_clusters > s->l2_size - l2_index) nb_clusters = s->l2_size - l2_index; @@ -879,13 +894,8 @@ static uint64_t alloc_cluster_offset(BlockDriverState *bs, /* We keep all QCOW_OFLAG_COPIED clusters */ if (cluster_offset & QCOW_OFLAG_COPIED) { - - for (i = 1; i < nb_clusters; i++) { - current = be64_to_cpu(l2_table[l2_index + i]); - if (cluster_offset + (i << s->cluster_bits) != current) - break; - } - nb_clusters = i; + nb_clusters = count_contiguous_clusters(nb_clusters, s->cluster_size, + &l2_table[l2_index], 0); nb_available = nb_clusters << (s->cluster_bits - 9); if (nb_available > n_end) @@ -903,46 +913,27 @@ static uint64_t alloc_cluster_offset(BlockDriverState *bs, /* how many available clusters ? */ - i = 0; while (i < nb_clusters) { + int j; + i += count_contiguous_free_clusters(nb_clusters - i, + &l2_table[l2_index + i]); - i++; - - if (!cluster_offset) { - - /* how many free clusters ? */ - - while (i < nb_clusters) { - cluster_offset = be64_to_cpu(l2_table[l2_index + i]); - if (cluster_offset != 0) - break; - i++; - } + cluster_offset = be64_to_cpu(l2_table[l2_index + i]); - if ((cluster_offset & QCOW_OFLAG_COPIED) || + if ((cluster_offset & QCOW_OFLAG_COPIED) || (cluster_offset & QCOW_OFLAG_COMPRESSED)) - break; - - } else { + break; - /* how many contiguous clusters ? */ + j = count_contiguous_clusters(nb_clusters - i, s->cluster_size, + &l2_table[l2_index + i], 0); - j = 1; - current = 0; - while (i < nb_clusters) { - current = be64_to_cpu(l2_table[l2_index + i]); - if (cluster_offset + (j << s->cluster_bits) != current) - break; + if (j) + free_any_clusters(bs, cluster_offset, j); - i++; - j++; - } + i += j; - free_any_clusters(bs, cluster_offset, j); - if (current) - break; - cluster_offset = current; - } + if(be64_to_cpu(l2_table[l2_index + i])) + break; } nb_clusters = i; @@ -2194,26 +2185,19 @@ static int64_t alloc_clusters_noref(BlockDriverState *bs, int64_t size) BDRVQcowState *s = bs->opaque; int i, nb_clusters; - nb_clusters = (size + s->cluster_size - 1) >> s->cluster_bits; - for(;;) { - if (get_refcount(bs, s->free_cluster_index) == 0) { - s->free_cluster_index++; - for(i = 1; i < nb_clusters; i++) { - if (get_refcount(bs, s->free_cluster_index) != 0) - goto not_found; - s->free_cluster_index++; - } + nb_clusters = size_to_clusters(s, size); +retry: + for(i = 0; i < nb_clusters; i++) { + int64_t i = s->free_cluster_index++; + if (get_refcount(bs, i) != 0) + goto retry; + } #ifdef DEBUG_ALLOC2 - printf("alloc_clusters: size=%lld -> %lld\n", - size, - (s->free_cluster_index - nb_clusters) << s->cluster_bits); + printf("alloc_clusters: size=%lld -> %lld\n", + size, + (s->free_cluster_index - nb_clusters) << s->cluster_bits); #endif - return (s->free_cluster_index - nb_clusters) << s->cluster_bits; - } else { - not_found: - s->free_cluster_index++; - } - } + return (s->free_cluster_index - nb_clusters) << s->cluster_bits; } static int64_t alloc_clusters(BlockDriverState *bs, int64_t size) @@ -2548,7 +2532,7 @@ static void check_refcounts(BlockDriverState *bs) uint16_t *refcount_table; size = bdrv_getlength(s->hd); - nb_clusters = (size + s->cluster_size - 1) >> s->cluster_bits; + nb_clusters = size_to_clusters(s, size); refcount_table = qemu_mallocz(nb_clusters * sizeof(uint16_t)); /* header */ @@ -2600,7 +2584,7 @@ static void dump_refcounts(BlockDriverState *bs) int refcount; size = bdrv_getlength(s->hd); - nb_clusters = (size + s->cluster_size - 1) >> s->cluster_bits; + nb_clusters = size_to_clusters(s, size); for(k = 0; k < nb_clusters;) { k1 = k; refcount = get_refcount(bs, k); |