diff options
Diffstat (limited to 'block/qcow2-refcount.c')
| -rw-r--r-- | block/qcow2-refcount.c | 84 |
1 files changed, 65 insertions, 19 deletions
diff --git a/block/qcow2-refcount.c b/block/qcow2-refcount.c index 54b19f86d..c2a5c0471 100644 --- a/block/qcow2-refcount.c +++ b/block/qcow2-refcount.c @@ -168,9 +168,12 @@ static int grow_refcount_table(BlockDriverState *bs, int min_size) cpu_to_be64w((uint64_t*)data, table_offset); cpu_to_be32w((uint32_t*)(data + 8), refcount_table_clusters); - if (bdrv_pwrite(s->hd, offsetof(QCowHeader, refcount_table_offset), - data, sizeof(data)) != sizeof(data)) + ret = bdrv_pwrite(s->hd, offsetof(QCowHeader, refcount_table_offset), + data, sizeof(data)); + if (ret != sizeof(data)) { goto fail; + } + qemu_free(s->refcount_table); old_table_offset = s->refcount_table_offset; old_table_size = s->refcount_table_size; @@ -183,7 +186,7 @@ static int grow_refcount_table(BlockDriverState *bs, int min_size) return 0; fail: qemu_free(new_table); - return -EIO; + return ret < 0 ? ret : -EIO; } @@ -266,22 +269,26 @@ static int write_refcount_block_entries(BDRVQcowState *s, } /* XXX: cache several refcount block clusters ? */ -static int update_refcount(BlockDriverState *bs, - int64_t offset, int64_t length, - int addend) +static int QEMU_WARN_UNUSED_RESULT update_refcount(BlockDriverState *bs, + int64_t offset, int64_t length, int addend) { BDRVQcowState *s = bs->opaque; int64_t start, last, cluster_offset; int64_t refcount_block_offset = 0; int64_t table_index = -1, old_table_index; int first_index = -1, last_index = -1; + int ret; #ifdef DEBUG_ALLOC2 printf("update_refcount: offset=%" PRId64 " size=%" PRId64 " addend=%d\n", offset, length, addend); #endif - if (length <= 0) + if (length < 0) { return -EINVAL; + } else if (length == 0) { + return 0; + } + start = offset & ~(s->cluster_size - 1); last = (offset + length - 1) & ~(s->cluster_size - 1); for(cluster_offset = start; cluster_offset <= last; @@ -289,6 +296,7 @@ static int update_refcount(BlockDriverState *bs, { int block_index, refcount; int64_t cluster_index = cluster_offset >> s->cluster_bits; + int64_t new_block; /* Only write refcount block to disk when we are done with it */ old_table_index = table_index; @@ -306,10 +314,12 @@ static int update_refcount(BlockDriverState *bs, } /* Load the refcount block and allocate it if needed */ - refcount_block_offset = alloc_refcount_block(bs, cluster_index); - if (refcount_block_offset < 0) { - return refcount_block_offset; + new_block = alloc_refcount_block(bs, cluster_index); + if (new_block < 0) { + ret = new_block; + goto fail; } + refcount_block_offset = new_block; /* we can update the count and save it */ block_index = cluster_index & @@ -323,24 +333,38 @@ static int update_refcount(BlockDriverState *bs, refcount = be16_to_cpu(s->refcount_block_cache[block_index]); refcount += addend; - if (refcount < 0 || refcount > 0xffff) - return -EINVAL; + if (refcount < 0 || refcount > 0xffff) { + ret = -EINVAL; + goto fail; + } if (refcount == 0 && cluster_index < s->free_cluster_index) { s->free_cluster_index = cluster_index; } s->refcount_block_cache[block_index] = cpu_to_be16(refcount); } + ret = 0; +fail: + /* Write last changed block to disk */ if (refcount_block_offset != 0) { if (write_refcount_block_entries(s, refcount_block_offset, first_index, last_index) < 0) { - return -EIO; + return ret < 0 ? ret : -EIO; } } - return 0; + /* + * Try do undo any updates if an error is returned (This may succeed in + * some cases like ENOSPC for allocating a new refcount block) + */ + if (ret < 0) { + int dummy; + dummy = update_refcount(bs, offset, cluster_offset - offset, -addend); + } + + return ret; } /* addend must be 1 or -1 */ @@ -390,9 +414,13 @@ retry: int64_t qcow2_alloc_clusters(BlockDriverState *bs, int64_t size) { int64_t offset; + int ret; offset = alloc_clusters_noref(bs, size); - update_refcount(bs, offset, size, 1); + ret = update_refcount(bs, offset, size, 1); + if (ret < 0) { + return ret; + } return offset; } @@ -407,6 +435,9 @@ int64_t qcow2_alloc_bytes(BlockDriverState *bs, int size) assert(size > 0 && size <= s->cluster_size); if (s->free_byte_offset == 0) { s->free_byte_offset = qcow2_alloc_clusters(bs, s->cluster_size); + if (s->free_byte_offset < 0) { + return s->free_byte_offset; + } } redo: free_in_cluster = s->cluster_size - @@ -422,6 +453,9 @@ int64_t qcow2_alloc_bytes(BlockDriverState *bs, int size) update_cluster_refcount(bs, offset >> s->cluster_bits, 1); } else { offset = qcow2_alloc_clusters(bs, s->cluster_size); + if (offset < 0) { + return offset; + } cluster_offset = s->free_byte_offset & ~(s->cluster_size - 1); if ((cluster_offset + s->cluster_size) == offset) { /* we are lucky: contiguous data */ @@ -439,7 +473,13 @@ int64_t qcow2_alloc_bytes(BlockDriverState *bs, int size) void qcow2_free_clusters(BlockDriverState *bs, int64_t offset, int64_t size) { - update_refcount(bs, offset, size, -1); + int ret; + + ret = update_refcount(bs, offset, size, -1); + if (ret < 0) { + fprintf(stderr, "qcow2_free_clusters failed: %s\n", strerror(-ret)); + abort(); + } } /* @@ -549,9 +589,15 @@ int qcow2_update_snapshot_refcount(BlockDriverState *bs, if (offset & QCOW_OFLAG_COMPRESSED) { nb_csectors = ((offset >> s->csize_shift) & s->csize_mask) + 1; - if (addend != 0) - update_refcount(bs, (offset & s->cluster_offset_mask) & ~511, - nb_csectors * 512, addend); + if (addend != 0) { + int ret; + ret = update_refcount(bs, + (offset & s->cluster_offset_mask) & ~511, + nb_csectors * 512, addend); + if (ret < 0) { + goto fail; + } + } /* compressed clusters are never modified */ refcount = 2; } else { |