root / block / qcow2-refcount.c @ 93913dfd
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/*
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* Block driver for the QCOW version 2 format
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*
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* Copyright (c) 2004-2006 Fabrice Bellard
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
|
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* of this software and associated documentation files (the "Software"), to deal
|
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* in the Software without restriction, including without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
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* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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* THE SOFTWARE.
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*/
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#include "qemu-common.h" |
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#include "block_int.h" |
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#include "block/qcow2.h" |
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|
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static int64_t alloc_clusters_noref(BlockDriverState *bs, int64_t size);
|
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static int QEMU_WARN_UNUSED_RESULT update_refcount(BlockDriverState *bs, |
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int64_t offset, int64_t length, |
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int addend);
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|
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|
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/*********************************************************/
|
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/* refcount handling */
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|
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int qcow2_refcount_init(BlockDriverState *bs)
|
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{
|
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BDRVQcowState *s = bs->opaque; |
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int ret, refcount_table_size2, i;
|
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|
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refcount_table_size2 = s->refcount_table_size * sizeof(uint64_t);
|
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s->refcount_table = qemu_malloc(refcount_table_size2); |
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if (s->refcount_table_size > 0) { |
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BLKDBG_EVENT(bs->file, BLKDBG_REFTABLE_LOAD); |
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ret = bdrv_pread(bs->file, s->refcount_table_offset, |
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s->refcount_table, refcount_table_size2); |
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if (ret != refcount_table_size2)
|
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goto fail;
|
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for(i = 0; i < s->refcount_table_size; i++) |
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be64_to_cpus(&s->refcount_table[i]); |
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} |
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return 0; |
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fail:
|
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return -ENOMEM;
|
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} |
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|
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void qcow2_refcount_close(BlockDriverState *bs)
|
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{
|
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BDRVQcowState *s = bs->opaque; |
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qemu_free(s->refcount_table); |
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} |
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|
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|
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static int load_refcount_block(BlockDriverState *bs, |
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int64_t refcount_block_offset, |
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void **refcount_block)
|
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{
|
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BDRVQcowState *s = bs->opaque; |
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int ret;
|
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|
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BLKDBG_EVENT(bs->file, BLKDBG_REFBLOCK_LOAD); |
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ret = qcow2_cache_get(bs, s->refcount_block_cache, refcount_block_offset, |
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refcount_block); |
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|
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return ret;
|
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} |
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|
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/*
|
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* Returns the refcount of the cluster given by its index. Any non-negative
|
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* return value is the refcount of the cluster, negative values are -errno
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* and indicate an error.
|
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*/
|
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static int get_refcount(BlockDriverState *bs, int64_t cluster_index) |
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{
|
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BDRVQcowState *s = bs->opaque; |
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int refcount_table_index, block_index;
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int64_t refcount_block_offset; |
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int ret;
|
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uint16_t *refcount_block; |
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uint16_t refcount; |
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|
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refcount_table_index = cluster_index >> (s->cluster_bits - REFCOUNT_SHIFT); |
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if (refcount_table_index >= s->refcount_table_size)
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return 0; |
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refcount_block_offset = s->refcount_table[refcount_table_index]; |
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if (!refcount_block_offset)
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return 0; |
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|
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ret = qcow2_cache_get(bs, s->refcount_block_cache, refcount_block_offset, |
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(void**) &refcount_block);
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if (ret < 0) { |
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return ret;
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} |
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|
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block_index = cluster_index & |
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((1 << (s->cluster_bits - REFCOUNT_SHIFT)) - 1); |
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refcount = be16_to_cpu(refcount_block[block_index]); |
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|
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ret = qcow2_cache_put(bs, s->refcount_block_cache, |
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(void**) &refcount_block);
|
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if (ret < 0) { |
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return ret;
|
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} |
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|
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return refcount;
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} |
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|
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/*
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* Rounds the refcount table size up to avoid growing the table for each single
|
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* refcount block that is allocated.
|
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*/
|
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static unsigned int next_refcount_table_size(BDRVQcowState *s, |
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unsigned int min_size) |
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{
|
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unsigned int min_clusters = (min_size >> (s->cluster_bits - 3)) + 1; |
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unsigned int refcount_table_clusters = |
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MAX(1, s->refcount_table_size >> (s->cluster_bits - 3)); |
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|
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while (min_clusters > refcount_table_clusters) {
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refcount_table_clusters = (refcount_table_clusters * 3 + 1) / 2; |
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} |
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|
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return refcount_table_clusters << (s->cluster_bits - 3); |
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} |
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|
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|
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/* Checks if two offsets are described by the same refcount block */
|
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static int in_same_refcount_block(BDRVQcowState *s, uint64_t offset_a, |
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uint64_t offset_b) |
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{
|
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uint64_t block_a = offset_a >> (2 * s->cluster_bits - REFCOUNT_SHIFT);
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uint64_t block_b = offset_b >> (2 * s->cluster_bits - REFCOUNT_SHIFT);
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|
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return (block_a == block_b);
|
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} |
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|
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/*
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* Loads a refcount block. If it doesn't exist yet, it is allocated first
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* (including growing the refcount table if needed).
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*
|
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* Returns 0 on success or -errno in error case
|
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*/
|
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static int alloc_refcount_block(BlockDriverState *bs, |
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int64_t cluster_index, uint16_t **refcount_block) |
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{
|
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BDRVQcowState *s = bs->opaque; |
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unsigned int refcount_table_index; |
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int ret;
|
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|
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BLKDBG_EVENT(bs->file, BLKDBG_REFBLOCK_ALLOC); |
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|
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/* Find the refcount block for the given cluster */
|
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refcount_table_index = cluster_index >> (s->cluster_bits - REFCOUNT_SHIFT); |
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|
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if (refcount_table_index < s->refcount_table_size) {
|
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|
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uint64_t refcount_block_offset = |
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s->refcount_table[refcount_table_index]; |
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|
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/* If it's already there, we're done */
|
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if (refcount_block_offset) {
|
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return load_refcount_block(bs, refcount_block_offset,
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(void**) refcount_block);
|
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} |
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} |
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|
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/*
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* If we came here, we need to allocate something. Something is at least
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* a cluster for the new refcount block. It may also include a new refcount
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* table if the old refcount table is too small.
|
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*
|
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* Note that allocating clusters here needs some special care:
|
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*
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* - We can't use the normal qcow2_alloc_clusters(), it would try to
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* increase the refcount and very likely we would end up with an endless
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* recursion. Instead we must place the refcount blocks in a way that
|
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* they can describe them themselves.
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*
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* - We need to consider that at this point we are inside update_refcounts
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* and doing the initial refcount increase. This means that some clusters
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* have already been allocated by the caller, but their refcount isn't
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* accurate yet. free_cluster_index tells us where this allocation ends
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* as long as we don't overwrite it by freeing clusters.
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*
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* - alloc_clusters_noref and qcow2_free_clusters may load a different
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* refcount block into the cache
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*/
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|
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*refcount_block = NULL;
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|
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/* We write to the refcount table, so we might depend on L2 tables */
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qcow2_cache_flush(bs, s->l2_table_cache); |
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|
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/* Allocate the refcount block itself and mark it as used */
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int64_t new_block = alloc_clusters_noref(bs, s->cluster_size); |
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if (new_block < 0) { |
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return new_block;
|
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} |
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|
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#ifdef DEBUG_ALLOC2
|
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fprintf(stderr, "qcow2: Allocate refcount block %d for %" PRIx64
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" at %" PRIx64 "\n", |
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refcount_table_index, cluster_index << s->cluster_bits, new_block); |
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#endif
|
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|
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if (in_same_refcount_block(s, new_block, cluster_index << s->cluster_bits)) {
|
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/* Zero the new refcount block before updating it */
|
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ret = qcow2_cache_get_empty(bs, s->refcount_block_cache, new_block, |
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(void**) refcount_block);
|
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if (ret < 0) { |
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goto fail_block;
|
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} |
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|
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memset(*refcount_block, 0, s->cluster_size);
|
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|
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/* The block describes itself, need to update the cache */
|
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int block_index = (new_block >> s->cluster_bits) &
|
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((1 << (s->cluster_bits - REFCOUNT_SHIFT)) - 1); |
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(*refcount_block)[block_index] = cpu_to_be16(1);
|
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} else {
|
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/* Described somewhere else. This can recurse at most twice before we
|
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* arrive at a block that describes itself. */
|
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ret = update_refcount(bs, new_block, s->cluster_size, 1);
|
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if (ret < 0) { |
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goto fail_block;
|
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} |
| 239 |
|
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bdrv_flush(bs->file); |
| 241 |
|
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/* Initialize the new refcount block only after updating its refcount,
|
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* update_refcount uses the refcount cache itself */
|
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ret = qcow2_cache_get_empty(bs, s->refcount_block_cache, new_block, |
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(void**) refcount_block);
|
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if (ret < 0) { |
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goto fail_block;
|
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} |
| 249 |
|
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memset(*refcount_block, 0, s->cluster_size);
|
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} |
| 252 |
|
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/* Now the new refcount block needs to be written to disk */
|
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BLKDBG_EVENT(bs->file, BLKDBG_REFBLOCK_ALLOC_WRITE); |
| 255 |
qcow2_cache_entry_mark_dirty(s->refcount_block_cache, *refcount_block); |
| 256 |
ret = qcow2_cache_flush(bs, s->refcount_block_cache); |
| 257 |
if (ret < 0) { |
| 258 |
goto fail_block;
|
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} |
| 260 |
|
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/* If the refcount table is big enough, just hook the block up there */
|
| 262 |
if (refcount_table_index < s->refcount_table_size) {
|
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uint64_t data64 = cpu_to_be64(new_block); |
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BLKDBG_EVENT(bs->file, BLKDBG_REFBLOCK_ALLOC_HOOKUP); |
| 265 |
ret = bdrv_pwrite_sync(bs->file, |
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s->refcount_table_offset + refcount_table_index * sizeof(uint64_t),
|
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&data64, sizeof(data64));
|
| 268 |
if (ret < 0) { |
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goto fail_block;
|
| 270 |
} |
| 271 |
|
| 272 |
s->refcount_table[refcount_table_index] = new_block; |
| 273 |
return 0; |
| 274 |
} |
| 275 |
|
| 276 |
ret = qcow2_cache_put(bs, s->refcount_block_cache, (void**) refcount_block);
|
| 277 |
if (ret < 0) { |
| 278 |
goto fail_block;
|
| 279 |
} |
| 280 |
|
| 281 |
/*
|
| 282 |
* If we come here, we need to grow the refcount table. Again, a new
|
| 283 |
* refcount table needs some space and we can't simply allocate to avoid
|
| 284 |
* endless recursion.
|
| 285 |
*
|
| 286 |
* Therefore let's grab new refcount blocks at the end of the image, which
|
| 287 |
* will describe themselves and the new refcount table. This way we can
|
| 288 |
* reference them only in the new table and do the switch to the new
|
| 289 |
* refcount table at once without producing an inconsistent state in
|
| 290 |
* between.
|
| 291 |
*/
|
| 292 |
BLKDBG_EVENT(bs->file, BLKDBG_REFTABLE_GROW); |
| 293 |
|
| 294 |
/* Calculate the number of refcount blocks needed so far */
|
| 295 |
uint64_t refcount_block_clusters = 1 << (s->cluster_bits - REFCOUNT_SHIFT);
|
| 296 |
uint64_t blocks_used = (s->free_cluster_index + |
| 297 |
refcount_block_clusters - 1) / refcount_block_clusters;
|
| 298 |
|
| 299 |
/* And now we need at least one block more for the new metadata */
|
| 300 |
uint64_t table_size = next_refcount_table_size(s, blocks_used + 1);
|
| 301 |
uint64_t last_table_size; |
| 302 |
uint64_t blocks_clusters; |
| 303 |
do {
|
| 304 |
uint64_t table_clusters = size_to_clusters(s, table_size); |
| 305 |
blocks_clusters = 1 +
|
| 306 |
((table_clusters + refcount_block_clusters - 1)
|
| 307 |
/ refcount_block_clusters); |
| 308 |
uint64_t meta_clusters = table_clusters + blocks_clusters; |
| 309 |
|
| 310 |
last_table_size = table_size; |
| 311 |
table_size = next_refcount_table_size(s, blocks_used + |
| 312 |
((meta_clusters + refcount_block_clusters - 1)
|
| 313 |
/ refcount_block_clusters)); |
| 314 |
|
| 315 |
} while (last_table_size != table_size);
|
| 316 |
|
| 317 |
#ifdef DEBUG_ALLOC2
|
| 318 |
fprintf(stderr, "qcow2: Grow refcount table %" PRId32 " => %" PRId64 "\n", |
| 319 |
s->refcount_table_size, table_size); |
| 320 |
#endif
|
| 321 |
|
| 322 |
/* Create the new refcount table and blocks */
|
| 323 |
uint64_t meta_offset = (blocks_used * refcount_block_clusters) * |
| 324 |
s->cluster_size; |
| 325 |
uint64_t table_offset = meta_offset + blocks_clusters * s->cluster_size; |
| 326 |
uint16_t *new_blocks = qemu_mallocz(blocks_clusters * s->cluster_size); |
| 327 |
uint64_t *new_table = qemu_mallocz(table_size * sizeof(uint64_t));
|
| 328 |
|
| 329 |
assert(meta_offset >= (s->free_cluster_index * s->cluster_size)); |
| 330 |
|
| 331 |
/* Fill the new refcount table */
|
| 332 |
memcpy(new_table, s->refcount_table, |
| 333 |
s->refcount_table_size * sizeof(uint64_t));
|
| 334 |
new_table[refcount_table_index] = new_block; |
| 335 |
|
| 336 |
int i;
|
| 337 |
for (i = 0; i < blocks_clusters; i++) { |
| 338 |
new_table[blocks_used + i] = meta_offset + (i * s->cluster_size); |
| 339 |
} |
| 340 |
|
| 341 |
/* Fill the refcount blocks */
|
| 342 |
uint64_t table_clusters = size_to_clusters(s, table_size * sizeof(uint64_t));
|
| 343 |
int block = 0; |
| 344 |
for (i = 0; i < table_clusters + blocks_clusters; i++) { |
| 345 |
new_blocks[block++] = cpu_to_be16(1);
|
| 346 |
} |
| 347 |
|
| 348 |
/* Write refcount blocks to disk */
|
| 349 |
BLKDBG_EVENT(bs->file, BLKDBG_REFBLOCK_ALLOC_WRITE_BLOCKS); |
| 350 |
ret = bdrv_pwrite_sync(bs->file, meta_offset, new_blocks, |
| 351 |
blocks_clusters * s->cluster_size); |
| 352 |
qemu_free(new_blocks); |
| 353 |
if (ret < 0) { |
| 354 |
goto fail_table;
|
| 355 |
} |
| 356 |
|
| 357 |
/* Write refcount table to disk */
|
| 358 |
for(i = 0; i < table_size; i++) { |
| 359 |
cpu_to_be64s(&new_table[i]); |
| 360 |
} |
| 361 |
|
| 362 |
BLKDBG_EVENT(bs->file, BLKDBG_REFBLOCK_ALLOC_WRITE_TABLE); |
| 363 |
ret = bdrv_pwrite_sync(bs->file, table_offset, new_table, |
| 364 |
table_size * sizeof(uint64_t));
|
| 365 |
if (ret < 0) { |
| 366 |
goto fail_table;
|
| 367 |
} |
| 368 |
|
| 369 |
for(i = 0; i < table_size; i++) { |
| 370 |
cpu_to_be64s(&new_table[i]); |
| 371 |
} |
| 372 |
|
| 373 |
/* Hook up the new refcount table in the qcow2 header */
|
| 374 |
uint8_t data[12];
|
| 375 |
cpu_to_be64w((uint64_t*)data, table_offset); |
| 376 |
cpu_to_be32w((uint32_t*)(data + 8), table_clusters);
|
| 377 |
BLKDBG_EVENT(bs->file, BLKDBG_REFBLOCK_ALLOC_SWITCH_TABLE); |
| 378 |
ret = bdrv_pwrite_sync(bs->file, offsetof(QCowHeader, refcount_table_offset), |
| 379 |
data, sizeof(data));
|
| 380 |
if (ret < 0) { |
| 381 |
goto fail_table;
|
| 382 |
} |
| 383 |
|
| 384 |
/* And switch it in memory */
|
| 385 |
uint64_t old_table_offset = s->refcount_table_offset; |
| 386 |
uint64_t old_table_size = s->refcount_table_size; |
| 387 |
|
| 388 |
qemu_free(s->refcount_table); |
| 389 |
s->refcount_table = new_table; |
| 390 |
s->refcount_table_size = table_size; |
| 391 |
s->refcount_table_offset = table_offset; |
| 392 |
|
| 393 |
/* Free old table. Remember, we must not change free_cluster_index */
|
| 394 |
uint64_t old_free_cluster_index = s->free_cluster_index; |
| 395 |
qcow2_free_clusters(bs, old_table_offset, old_table_size * sizeof(uint64_t));
|
| 396 |
s->free_cluster_index = old_free_cluster_index; |
| 397 |
|
| 398 |
ret = load_refcount_block(bs, new_block, (void**) refcount_block);
|
| 399 |
if (ret < 0) { |
| 400 |
return ret;
|
| 401 |
} |
| 402 |
|
| 403 |
return new_block;
|
| 404 |
|
| 405 |
fail_table:
|
| 406 |
qemu_free(new_table); |
| 407 |
fail_block:
|
| 408 |
if (*refcount_block != NULL) { |
| 409 |
qcow2_cache_put(bs, s->refcount_block_cache, (void**) refcount_block);
|
| 410 |
} |
| 411 |
return ret;
|
| 412 |
} |
| 413 |
|
| 414 |
/* XXX: cache several refcount block clusters ? */
|
| 415 |
static int QEMU_WARN_UNUSED_RESULT update_refcount(BlockDriverState *bs, |
| 416 |
int64_t offset, int64_t length, int addend)
|
| 417 |
{
|
| 418 |
BDRVQcowState *s = bs->opaque; |
| 419 |
int64_t start, last, cluster_offset; |
| 420 |
uint16_t *refcount_block = NULL;
|
| 421 |
int64_t old_table_index = -1;
|
| 422 |
int ret;
|
| 423 |
|
| 424 |
#ifdef DEBUG_ALLOC2
|
| 425 |
printf("update_refcount: offset=%" PRId64 " size=%" PRId64 " addend=%d\n", |
| 426 |
offset, length, addend); |
| 427 |
#endif
|
| 428 |
if (length < 0) { |
| 429 |
return -EINVAL;
|
| 430 |
} else if (length == 0) { |
| 431 |
return 0; |
| 432 |
} |
| 433 |
|
| 434 |
if (addend < 0) { |
| 435 |
qcow2_cache_set_dependency(bs, s->refcount_block_cache, |
| 436 |
s->l2_table_cache); |
| 437 |
} |
| 438 |
|
| 439 |
start = offset & ~(s->cluster_size - 1);
|
| 440 |
last = (offset + length - 1) & ~(s->cluster_size - 1); |
| 441 |
for(cluster_offset = start; cluster_offset <= last;
|
| 442 |
cluster_offset += s->cluster_size) |
| 443 |
{
|
| 444 |
int block_index, refcount;
|
| 445 |
int64_t cluster_index = cluster_offset >> s->cluster_bits; |
| 446 |
int64_t table_index = |
| 447 |
cluster_index >> (s->cluster_bits - REFCOUNT_SHIFT); |
| 448 |
|
| 449 |
/* Load the refcount block and allocate it if needed */
|
| 450 |
if (table_index != old_table_index) {
|
| 451 |
if (refcount_block) {
|
| 452 |
ret = qcow2_cache_put(bs, s->refcount_block_cache, |
| 453 |
(void**) &refcount_block);
|
| 454 |
if (ret < 0) { |
| 455 |
goto fail;
|
| 456 |
} |
| 457 |
} |
| 458 |
|
| 459 |
ret = alloc_refcount_block(bs, cluster_index, &refcount_block); |
| 460 |
if (ret < 0) { |
| 461 |
goto fail;
|
| 462 |
} |
| 463 |
} |
| 464 |
old_table_index = table_index; |
| 465 |
|
| 466 |
qcow2_cache_entry_mark_dirty(s->refcount_block_cache, refcount_block); |
| 467 |
|
| 468 |
/* we can update the count and save it */
|
| 469 |
block_index = cluster_index & |
| 470 |
((1 << (s->cluster_bits - REFCOUNT_SHIFT)) - 1); |
| 471 |
|
| 472 |
refcount = be16_to_cpu(refcount_block[block_index]); |
| 473 |
refcount += addend; |
| 474 |
if (refcount < 0 || refcount > 0xffff) { |
| 475 |
ret = -EINVAL; |
| 476 |
goto fail;
|
| 477 |
} |
| 478 |
if (refcount == 0 && cluster_index < s->free_cluster_index) { |
| 479 |
s->free_cluster_index = cluster_index; |
| 480 |
} |
| 481 |
refcount_block[block_index] = cpu_to_be16(refcount); |
| 482 |
} |
| 483 |
|
| 484 |
ret = 0;
|
| 485 |
fail:
|
| 486 |
/* Write last changed block to disk */
|
| 487 |
if (refcount_block) {
|
| 488 |
int wret;
|
| 489 |
wret = qcow2_cache_put(bs, s->refcount_block_cache, |
| 490 |
(void**) &refcount_block);
|
| 491 |
if (wret < 0) { |
| 492 |
return ret < 0 ? ret : wret; |
| 493 |
} |
| 494 |
} |
| 495 |
|
| 496 |
/*
|
| 497 |
* Try do undo any updates if an error is returned (This may succeed in
|
| 498 |
* some cases like ENOSPC for allocating a new refcount block)
|
| 499 |
*/
|
| 500 |
if (ret < 0) { |
| 501 |
int dummy;
|
| 502 |
dummy = update_refcount(bs, offset, cluster_offset - offset, -addend); |
| 503 |
(void)dummy;
|
| 504 |
} |
| 505 |
|
| 506 |
return ret;
|
| 507 |
} |
| 508 |
|
| 509 |
/*
|
| 510 |
* Increases or decreases the refcount of a given cluster by one.
|
| 511 |
* addend must be 1 or -1.
|
| 512 |
*
|
| 513 |
* If the return value is non-negative, it is the new refcount of the cluster.
|
| 514 |
* If it is negative, it is -errno and indicates an error.
|
| 515 |
*/
|
| 516 |
static int update_cluster_refcount(BlockDriverState *bs, |
| 517 |
int64_t cluster_index, |
| 518 |
int addend)
|
| 519 |
{
|
| 520 |
BDRVQcowState *s = bs->opaque; |
| 521 |
int ret;
|
| 522 |
|
| 523 |
ret = update_refcount(bs, cluster_index << s->cluster_bits, 1, addend);
|
| 524 |
if (ret < 0) { |
| 525 |
return ret;
|
| 526 |
} |
| 527 |
|
| 528 |
bdrv_flush(bs->file); |
| 529 |
|
| 530 |
return get_refcount(bs, cluster_index);
|
| 531 |
} |
| 532 |
|
| 533 |
|
| 534 |
|
| 535 |
/*********************************************************/
|
| 536 |
/* cluster allocation functions */
|
| 537 |
|
| 538 |
|
| 539 |
|
| 540 |
/* return < 0 if error */
|
| 541 |
static int64_t alloc_clusters_noref(BlockDriverState *bs, int64_t size)
|
| 542 |
{
|
| 543 |
BDRVQcowState *s = bs->opaque; |
| 544 |
int i, nb_clusters, refcount;
|
| 545 |
|
| 546 |
nb_clusters = size_to_clusters(s, size); |
| 547 |
retry:
|
| 548 |
for(i = 0; i < nb_clusters; i++) { |
| 549 |
int64_t next_cluster_index = s->free_cluster_index++; |
| 550 |
refcount = get_refcount(bs, next_cluster_index); |
| 551 |
|
| 552 |
if (refcount < 0) { |
| 553 |
return refcount;
|
| 554 |
} else if (refcount != 0) { |
| 555 |
goto retry;
|
| 556 |
} |
| 557 |
} |
| 558 |
#ifdef DEBUG_ALLOC2
|
| 559 |
printf("alloc_clusters: size=%" PRId64 " -> %" PRId64 "\n", |
| 560 |
size, |
| 561 |
(s->free_cluster_index - nb_clusters) << s->cluster_bits); |
| 562 |
#endif
|
| 563 |
return (s->free_cluster_index - nb_clusters) << s->cluster_bits;
|
| 564 |
} |
| 565 |
|
| 566 |
int64_t qcow2_alloc_clusters(BlockDriverState *bs, int64_t size) |
| 567 |
{
|
| 568 |
int64_t offset; |
| 569 |
int ret;
|
| 570 |
|
| 571 |
BLKDBG_EVENT(bs->file, BLKDBG_CLUSTER_ALLOC); |
| 572 |
offset = alloc_clusters_noref(bs, size); |
| 573 |
if (offset < 0) { |
| 574 |
return offset;
|
| 575 |
} |
| 576 |
|
| 577 |
ret = update_refcount(bs, offset, size, 1);
|
| 578 |
if (ret < 0) { |
| 579 |
return ret;
|
| 580 |
} |
| 581 |
|
| 582 |
return offset;
|
| 583 |
} |
| 584 |
|
| 585 |
/* only used to allocate compressed sectors. We try to allocate
|
| 586 |
contiguous sectors. size must be <= cluster_size */
|
| 587 |
int64_t qcow2_alloc_bytes(BlockDriverState *bs, int size)
|
| 588 |
{
|
| 589 |
BDRVQcowState *s = bs->opaque; |
| 590 |
int64_t offset, cluster_offset; |
| 591 |
int free_in_cluster;
|
| 592 |
|
| 593 |
BLKDBG_EVENT(bs->file, BLKDBG_CLUSTER_ALLOC_BYTES); |
| 594 |
assert(size > 0 && size <= s->cluster_size);
|
| 595 |
if (s->free_byte_offset == 0) { |
| 596 |
s->free_byte_offset = qcow2_alloc_clusters(bs, s->cluster_size); |
| 597 |
if (s->free_byte_offset < 0) { |
| 598 |
return s->free_byte_offset;
|
| 599 |
} |
| 600 |
} |
| 601 |
redo:
|
| 602 |
free_in_cluster = s->cluster_size - |
| 603 |
(s->free_byte_offset & (s->cluster_size - 1));
|
| 604 |
if (size <= free_in_cluster) {
|
| 605 |
/* enough space in current cluster */
|
| 606 |
offset = s->free_byte_offset; |
| 607 |
s->free_byte_offset += size; |
| 608 |
free_in_cluster -= size; |
| 609 |
if (free_in_cluster == 0) |
| 610 |
s->free_byte_offset = 0;
|
| 611 |
if ((offset & (s->cluster_size - 1)) != 0) |
| 612 |
update_cluster_refcount(bs, offset >> s->cluster_bits, 1);
|
| 613 |
} else {
|
| 614 |
offset = qcow2_alloc_clusters(bs, s->cluster_size); |
| 615 |
if (offset < 0) { |
| 616 |
return offset;
|
| 617 |
} |
| 618 |
cluster_offset = s->free_byte_offset & ~(s->cluster_size - 1);
|
| 619 |
if ((cluster_offset + s->cluster_size) == offset) {
|
| 620 |
/* we are lucky: contiguous data */
|
| 621 |
offset = s->free_byte_offset; |
| 622 |
update_cluster_refcount(bs, offset >> s->cluster_bits, 1);
|
| 623 |
s->free_byte_offset += size; |
| 624 |
} else {
|
| 625 |
s->free_byte_offset = offset; |
| 626 |
goto redo;
|
| 627 |
} |
| 628 |
} |
| 629 |
|
| 630 |
bdrv_flush(bs->file); |
| 631 |
return offset;
|
| 632 |
} |
| 633 |
|
| 634 |
void qcow2_free_clusters(BlockDriverState *bs,
|
| 635 |
int64_t offset, int64_t size) |
| 636 |
{
|
| 637 |
int ret;
|
| 638 |
|
| 639 |
BLKDBG_EVENT(bs->file, BLKDBG_CLUSTER_FREE); |
| 640 |
ret = update_refcount(bs, offset, size, -1);
|
| 641 |
if (ret < 0) { |
| 642 |
fprintf(stderr, "qcow2_free_clusters failed: %s\n", strerror(-ret));
|
| 643 |
/* TODO Remember the clusters to free them later and avoid leaking */
|
| 644 |
} |
| 645 |
} |
| 646 |
|
| 647 |
/*
|
| 648 |
* free_any_clusters
|
| 649 |
*
|
| 650 |
* free clusters according to its type: compressed or not
|
| 651 |
*
|
| 652 |
*/
|
| 653 |
|
| 654 |
void qcow2_free_any_clusters(BlockDriverState *bs,
|
| 655 |
uint64_t cluster_offset, int nb_clusters)
|
| 656 |
{
|
| 657 |
BDRVQcowState *s = bs->opaque; |
| 658 |
|
| 659 |
/* free the cluster */
|
| 660 |
|
| 661 |
if (cluster_offset & QCOW_OFLAG_COMPRESSED) {
|
| 662 |
int nb_csectors;
|
| 663 |
nb_csectors = ((cluster_offset >> s->csize_shift) & |
| 664 |
s->csize_mask) + 1;
|
| 665 |
qcow2_free_clusters(bs, |
| 666 |
(cluster_offset & s->cluster_offset_mask) & ~511,
|
| 667 |
nb_csectors * 512);
|
| 668 |
return;
|
| 669 |
} |
| 670 |
|
| 671 |
qcow2_free_clusters(bs, cluster_offset, nb_clusters << s->cluster_bits); |
| 672 |
|
| 673 |
return;
|
| 674 |
} |
| 675 |
|
| 676 |
|
| 677 |
|
| 678 |
/*********************************************************/
|
| 679 |
/* snapshots and image creation */
|
| 680 |
|
| 681 |
|
| 682 |
|
| 683 |
void qcow2_create_refcount_update(QCowCreateState *s, int64_t offset,
|
| 684 |
int64_t size) |
| 685 |
{
|
| 686 |
int refcount;
|
| 687 |
int64_t start, last, cluster_offset; |
| 688 |
uint16_t *p; |
| 689 |
|
| 690 |
start = offset & ~(s->cluster_size - 1);
|
| 691 |
last = (offset + size - 1) & ~(s->cluster_size - 1); |
| 692 |
for(cluster_offset = start; cluster_offset <= last;
|
| 693 |
cluster_offset += s->cluster_size) {
|
| 694 |
p = &s->refcount_block[cluster_offset >> s->cluster_bits]; |
| 695 |
refcount = be16_to_cpu(*p); |
| 696 |
refcount++; |
| 697 |
*p = cpu_to_be16(refcount); |
| 698 |
} |
| 699 |
} |
| 700 |
|
| 701 |
/* update the refcounts of snapshots and the copied flag */
|
| 702 |
int qcow2_update_snapshot_refcount(BlockDriverState *bs,
|
| 703 |
int64_t l1_table_offset, int l1_size, int addend) |
| 704 |
{
|
| 705 |
BDRVQcowState *s = bs->opaque; |
| 706 |
uint64_t *l1_table, *l2_table, l2_offset, offset, l1_size2, l1_allocated; |
| 707 |
int64_t old_offset, old_l2_offset; |
| 708 |
int i, j, l1_modified = 0, nb_csectors, refcount; |
| 709 |
int ret;
|
| 710 |
bool old_l2_writethrough, old_refcount_writethrough;
|
| 711 |
|
| 712 |
/* Switch caches to writeback mode during update */
|
| 713 |
old_l2_writethrough = |
| 714 |
qcow2_cache_set_writethrough(bs, s->l2_table_cache, false);
|
| 715 |
old_refcount_writethrough = |
| 716 |
qcow2_cache_set_writethrough(bs, s->refcount_block_cache, false);
|
| 717 |
|
| 718 |
l2_table = NULL;
|
| 719 |
l1_table = NULL;
|
| 720 |
l1_size2 = l1_size * sizeof(uint64_t);
|
| 721 |
if (l1_table_offset != s->l1_table_offset) {
|
| 722 |
if (l1_size2 != 0) { |
| 723 |
l1_table = qemu_mallocz(align_offset(l1_size2, 512));
|
| 724 |
} else {
|
| 725 |
l1_table = NULL;
|
| 726 |
} |
| 727 |
l1_allocated = 1;
|
| 728 |
if (bdrv_pread(bs->file, l1_table_offset,
|
| 729 |
l1_table, l1_size2) != l1_size2) |
| 730 |
{
|
| 731 |
ret = -EIO; |
| 732 |
goto fail;
|
| 733 |
} |
| 734 |
|
| 735 |
for(i = 0;i < l1_size; i++) |
| 736 |
be64_to_cpus(&l1_table[i]); |
| 737 |
} else {
|
| 738 |
assert(l1_size == s->l1_size); |
| 739 |
l1_table = s->l1_table; |
| 740 |
l1_allocated = 0;
|
| 741 |
} |
| 742 |
|
| 743 |
for(i = 0; i < l1_size; i++) { |
| 744 |
l2_offset = l1_table[i]; |
| 745 |
if (l2_offset) {
|
| 746 |
old_l2_offset = l2_offset; |
| 747 |
l2_offset &= ~QCOW_OFLAG_COPIED; |
| 748 |
|
| 749 |
ret = qcow2_cache_get(bs, s->l2_table_cache, l2_offset, |
| 750 |
(void**) &l2_table);
|
| 751 |
if (ret < 0) { |
| 752 |
goto fail;
|
| 753 |
} |
| 754 |
|
| 755 |
for(j = 0; j < s->l2_size; j++) { |
| 756 |
offset = be64_to_cpu(l2_table[j]); |
| 757 |
if (offset != 0) { |
| 758 |
old_offset = offset; |
| 759 |
offset &= ~QCOW_OFLAG_COPIED; |
| 760 |
if (offset & QCOW_OFLAG_COMPRESSED) {
|
| 761 |
nb_csectors = ((offset >> s->csize_shift) & |
| 762 |
s->csize_mask) + 1;
|
| 763 |
if (addend != 0) { |
| 764 |
int ret;
|
| 765 |
ret = update_refcount(bs, |
| 766 |
(offset & s->cluster_offset_mask) & ~511,
|
| 767 |
nb_csectors * 512, addend);
|
| 768 |
if (ret < 0) { |
| 769 |
goto fail;
|
| 770 |
} |
| 771 |
|
| 772 |
/* TODO Flushing once for the whole function should
|
| 773 |
* be enough */
|
| 774 |
bdrv_flush(bs->file); |
| 775 |
} |
| 776 |
/* compressed clusters are never modified */
|
| 777 |
refcount = 2;
|
| 778 |
} else {
|
| 779 |
if (addend != 0) { |
| 780 |
refcount = update_cluster_refcount(bs, offset >> s->cluster_bits, addend); |
| 781 |
} else {
|
| 782 |
refcount = get_refcount(bs, offset >> s->cluster_bits); |
| 783 |
} |
| 784 |
|
| 785 |
if (refcount < 0) { |
| 786 |
ret = -EIO; |
| 787 |
goto fail;
|
| 788 |
} |
| 789 |
} |
| 790 |
|
| 791 |
if (refcount == 1) { |
| 792 |
offset |= QCOW_OFLAG_COPIED; |
| 793 |
} |
| 794 |
if (offset != old_offset) {
|
| 795 |
if (addend > 0) { |
| 796 |
qcow2_cache_set_dependency(bs, s->l2_table_cache, |
| 797 |
s->refcount_block_cache); |
| 798 |
} |
| 799 |
l2_table[j] = cpu_to_be64(offset); |
| 800 |
qcow2_cache_entry_mark_dirty(s->l2_table_cache, l2_table); |
| 801 |
} |
| 802 |
} |
| 803 |
} |
| 804 |
|
| 805 |
ret = qcow2_cache_put(bs, s->l2_table_cache, (void**) &l2_table);
|
| 806 |
if (ret < 0) { |
| 807 |
goto fail;
|
| 808 |
} |
| 809 |
|
| 810 |
|
| 811 |
if (addend != 0) { |
| 812 |
refcount = update_cluster_refcount(bs, l2_offset >> s->cluster_bits, addend); |
| 813 |
} else {
|
| 814 |
refcount = get_refcount(bs, l2_offset >> s->cluster_bits); |
| 815 |
} |
| 816 |
if (refcount < 0) { |
| 817 |
ret = -EIO; |
| 818 |
goto fail;
|
| 819 |
} else if (refcount == 1) { |
| 820 |
l2_offset |= QCOW_OFLAG_COPIED; |
| 821 |
} |
| 822 |
if (l2_offset != old_l2_offset) {
|
| 823 |
l1_table[i] = l2_offset; |
| 824 |
l1_modified = 1;
|
| 825 |
} |
| 826 |
} |
| 827 |
} |
| 828 |
|
| 829 |
ret = 0;
|
| 830 |
fail:
|
| 831 |
if (l2_table) {
|
| 832 |
qcow2_cache_put(bs, s->l2_table_cache, (void**) &l2_table);
|
| 833 |
} |
| 834 |
|
| 835 |
/* Enable writethrough cache mode again */
|
| 836 |
qcow2_cache_set_writethrough(bs, s->l2_table_cache, old_l2_writethrough); |
| 837 |
qcow2_cache_set_writethrough(bs, s->refcount_block_cache, |
| 838 |
old_refcount_writethrough); |
| 839 |
|
| 840 |
if (l1_modified) {
|
| 841 |
for(i = 0; i < l1_size; i++) |
| 842 |
cpu_to_be64s(&l1_table[i]); |
| 843 |
if (bdrv_pwrite_sync(bs->file, l1_table_offset, l1_table,
|
| 844 |
l1_size2) < 0)
|
| 845 |
goto fail;
|
| 846 |
for(i = 0; i < l1_size; i++) |
| 847 |
be64_to_cpus(&l1_table[i]); |
| 848 |
} |
| 849 |
if (l1_allocated)
|
| 850 |
qemu_free(l1_table); |
| 851 |
return ret;
|
| 852 |
} |
| 853 |
|
| 854 |
|
| 855 |
|
| 856 |
|
| 857 |
/*********************************************************/
|
| 858 |
/* refcount checking functions */
|
| 859 |
|
| 860 |
|
| 861 |
|
| 862 |
/*
|
| 863 |
* Increases the refcount for a range of clusters in a given refcount table.
|
| 864 |
* This is used to construct a temporary refcount table out of L1 and L2 tables
|
| 865 |
* which can be compared the the refcount table saved in the image.
|
| 866 |
*
|
| 867 |
* Modifies the number of errors in res.
|
| 868 |
*/
|
| 869 |
static void inc_refcounts(BlockDriverState *bs, |
| 870 |
BdrvCheckResult *res, |
| 871 |
uint16_t *refcount_table, |
| 872 |
int refcount_table_size,
|
| 873 |
int64_t offset, int64_t size) |
| 874 |
{
|
| 875 |
BDRVQcowState *s = bs->opaque; |
| 876 |
int64_t start, last, cluster_offset; |
| 877 |
int k;
|
| 878 |
|
| 879 |
if (size <= 0) |
| 880 |
return;
|
| 881 |
|
| 882 |
start = offset & ~(s->cluster_size - 1);
|
| 883 |
last = (offset + size - 1) & ~(s->cluster_size - 1); |
| 884 |
for(cluster_offset = start; cluster_offset <= last;
|
| 885 |
cluster_offset += s->cluster_size) {
|
| 886 |
k = cluster_offset >> s->cluster_bits; |
| 887 |
if (k < 0) { |
| 888 |
fprintf(stderr, "ERROR: invalid cluster offset=0x%" PRIx64 "\n", |
| 889 |
cluster_offset); |
| 890 |
res->corruptions++; |
| 891 |
} else if (k >= refcount_table_size) { |
| 892 |
fprintf(stderr, "Warning: cluster offset=0x%" PRIx64 " is after " |
| 893 |
"the end of the image file, can't properly check refcounts.\n",
|
| 894 |
cluster_offset); |
| 895 |
res->check_errors++; |
| 896 |
} else {
|
| 897 |
if (++refcount_table[k] == 0) { |
| 898 |
fprintf(stderr, "ERROR: overflow cluster offset=0x%" PRIx64
|
| 899 |
"\n", cluster_offset);
|
| 900 |
res->corruptions++; |
| 901 |
} |
| 902 |
} |
| 903 |
} |
| 904 |
} |
| 905 |
|
| 906 |
/*
|
| 907 |
* Increases the refcount in the given refcount table for the all clusters
|
| 908 |
* referenced in the L2 table. While doing so, performs some checks on L2
|
| 909 |
* entries.
|
| 910 |
*
|
| 911 |
* Returns the number of errors found by the checks or -errno if an internal
|
| 912 |
* error occurred.
|
| 913 |
*/
|
| 914 |
static int check_refcounts_l2(BlockDriverState *bs, BdrvCheckResult *res, |
| 915 |
uint16_t *refcount_table, int refcount_table_size, int64_t l2_offset,
|
| 916 |
int check_copied)
|
| 917 |
{
|
| 918 |
BDRVQcowState *s = bs->opaque; |
| 919 |
uint64_t *l2_table, offset; |
| 920 |
int i, l2_size, nb_csectors, refcount;
|
| 921 |
|
| 922 |
/* Read L2 table from disk */
|
| 923 |
l2_size = s->l2_size * sizeof(uint64_t);
|
| 924 |
l2_table = qemu_malloc(l2_size); |
| 925 |
|
| 926 |
if (bdrv_pread(bs->file, l2_offset, l2_table, l2_size) != l2_size)
|
| 927 |
goto fail;
|
| 928 |
|
| 929 |
/* Do the actual checks */
|
| 930 |
for(i = 0; i < s->l2_size; i++) { |
| 931 |
offset = be64_to_cpu(l2_table[i]); |
| 932 |
if (offset != 0) { |
| 933 |
if (offset & QCOW_OFLAG_COMPRESSED) {
|
| 934 |
/* Compressed clusters don't have QCOW_OFLAG_COPIED */
|
| 935 |
if (offset & QCOW_OFLAG_COPIED) {
|
| 936 |
fprintf(stderr, "ERROR: cluster %" PRId64 ": " |
| 937 |
"copied flag must never be set for compressed "
|
| 938 |
"clusters\n", offset >> s->cluster_bits);
|
| 939 |
offset &= ~QCOW_OFLAG_COPIED; |
| 940 |
res->corruptions++; |
| 941 |
} |
| 942 |
|
| 943 |
/* Mark cluster as used */
|
| 944 |
nb_csectors = ((offset >> s->csize_shift) & |
| 945 |
s->csize_mask) + 1;
|
| 946 |
offset &= s->cluster_offset_mask; |
| 947 |
inc_refcounts(bs, res, refcount_table, refcount_table_size, |
| 948 |
offset & ~511, nb_csectors * 512); |
| 949 |
} else {
|
| 950 |
/* QCOW_OFLAG_COPIED must be set iff refcount == 1 */
|
| 951 |
if (check_copied) {
|
| 952 |
uint64_t entry = offset; |
| 953 |
offset &= ~QCOW_OFLAG_COPIED; |
| 954 |
refcount = get_refcount(bs, offset >> s->cluster_bits); |
| 955 |
if (refcount < 0) { |
| 956 |
fprintf(stderr, "Can't get refcount for offset %"
|
| 957 |
PRIx64 ": %s\n", entry, strerror(-refcount));
|
| 958 |
goto fail;
|
| 959 |
} |
| 960 |
if ((refcount == 1) != ((entry & QCOW_OFLAG_COPIED) != 0)) { |
| 961 |
fprintf(stderr, "ERROR OFLAG_COPIED: offset=%"
|
| 962 |
PRIx64 " refcount=%d\n", entry, refcount);
|
| 963 |
res->corruptions++; |
| 964 |
} |
| 965 |
} |
| 966 |
|
| 967 |
/* Mark cluster as used */
|
| 968 |
offset &= ~QCOW_OFLAG_COPIED; |
| 969 |
inc_refcounts(bs, res, refcount_table,refcount_table_size, |
| 970 |
offset, s->cluster_size); |
| 971 |
|
| 972 |
/* Correct offsets are cluster aligned */
|
| 973 |
if (offset & (s->cluster_size - 1)) { |
| 974 |
fprintf(stderr, "ERROR offset=%" PRIx64 ": Cluster is not " |
| 975 |
"properly aligned; L2 entry corrupted.\n", offset);
|
| 976 |
res->corruptions++; |
| 977 |
} |
| 978 |
} |
| 979 |
} |
| 980 |
} |
| 981 |
|
| 982 |
qemu_free(l2_table); |
| 983 |
return 0; |
| 984 |
|
| 985 |
fail:
|
| 986 |
fprintf(stderr, "ERROR: I/O error in check_refcounts_l2\n");
|
| 987 |
qemu_free(l2_table); |
| 988 |
return -EIO;
|
| 989 |
} |
| 990 |
|
| 991 |
/*
|
| 992 |
* Increases the refcount for the L1 table, its L2 tables and all referenced
|
| 993 |
* clusters in the given refcount table. While doing so, performs some checks
|
| 994 |
* on L1 and L2 entries.
|
| 995 |
*
|
| 996 |
* Returns the number of errors found by the checks or -errno if an internal
|
| 997 |
* error occurred.
|
| 998 |
*/
|
| 999 |
static int check_refcounts_l1(BlockDriverState *bs, |
| 1000 |
BdrvCheckResult *res, |
| 1001 |
uint16_t *refcount_table, |
| 1002 |
int refcount_table_size,
|
| 1003 |
int64_t l1_table_offset, int l1_size,
|
| 1004 |
int check_copied)
|
| 1005 |
{
|
| 1006 |
BDRVQcowState *s = bs->opaque; |
| 1007 |
uint64_t *l1_table, l2_offset, l1_size2; |
| 1008 |
int i, refcount, ret;
|
| 1009 |
|
| 1010 |
l1_size2 = l1_size * sizeof(uint64_t);
|
| 1011 |
|
| 1012 |
/* Mark L1 table as used */
|
| 1013 |
inc_refcounts(bs, res, refcount_table, refcount_table_size, |
| 1014 |
l1_table_offset, l1_size2); |
| 1015 |
|
| 1016 |
/* Read L1 table entries from disk */
|
| 1017 |
if (l1_size2 == 0) { |
| 1018 |
l1_table = NULL;
|
| 1019 |
} else {
|
| 1020 |
l1_table = qemu_malloc(l1_size2); |
| 1021 |
if (bdrv_pread(bs->file, l1_table_offset,
|
| 1022 |
l1_table, l1_size2) != l1_size2) |
| 1023 |
goto fail;
|
| 1024 |
for(i = 0;i < l1_size; i++) |
| 1025 |
be64_to_cpus(&l1_table[i]); |
| 1026 |
} |
| 1027 |
|
| 1028 |
/* Do the actual checks */
|
| 1029 |
for(i = 0; i < l1_size; i++) { |
| 1030 |
l2_offset = l1_table[i]; |
| 1031 |
if (l2_offset) {
|
| 1032 |
/* QCOW_OFLAG_COPIED must be set iff refcount == 1 */
|
| 1033 |
if (check_copied) {
|
| 1034 |
refcount = get_refcount(bs, (l2_offset & ~QCOW_OFLAG_COPIED) |
| 1035 |
>> s->cluster_bits); |
| 1036 |
if (refcount < 0) { |
| 1037 |
fprintf(stderr, "Can't get refcount for l2_offset %"
|
| 1038 |
PRIx64 ": %s\n", l2_offset, strerror(-refcount));
|
| 1039 |
goto fail;
|
| 1040 |
} |
| 1041 |
if ((refcount == 1) != ((l2_offset & QCOW_OFLAG_COPIED) != 0)) { |
| 1042 |
fprintf(stderr, "ERROR OFLAG_COPIED: l2_offset=%" PRIx64
|
| 1043 |
" refcount=%d\n", l2_offset, refcount);
|
| 1044 |
res->corruptions++; |
| 1045 |
} |
| 1046 |
} |
| 1047 |
|
| 1048 |
/* Mark L2 table as used */
|
| 1049 |
l2_offset &= ~QCOW_OFLAG_COPIED; |
| 1050 |
inc_refcounts(bs, res, refcount_table, refcount_table_size, |
| 1051 |
l2_offset, s->cluster_size); |
| 1052 |
|
| 1053 |
/* L2 tables are cluster aligned */
|
| 1054 |
if (l2_offset & (s->cluster_size - 1)) { |
| 1055 |
fprintf(stderr, "ERROR l2_offset=%" PRIx64 ": Table is not " |
| 1056 |
"cluster aligned; L1 entry corrupted\n", l2_offset);
|
| 1057 |
res->corruptions++; |
| 1058 |
} |
| 1059 |
|
| 1060 |
/* Process and check L2 entries */
|
| 1061 |
ret = check_refcounts_l2(bs, res, refcount_table, |
| 1062 |
refcount_table_size, l2_offset, check_copied); |
| 1063 |
if (ret < 0) { |
| 1064 |
goto fail;
|
| 1065 |
} |
| 1066 |
} |
| 1067 |
} |
| 1068 |
qemu_free(l1_table); |
| 1069 |
return 0; |
| 1070 |
|
| 1071 |
fail:
|
| 1072 |
fprintf(stderr, "ERROR: I/O error in check_refcounts_l1\n");
|
| 1073 |
res->check_errors++; |
| 1074 |
qemu_free(l1_table); |
| 1075 |
return -EIO;
|
| 1076 |
} |
| 1077 |
|
| 1078 |
/*
|
| 1079 |
* Checks an image for refcount consistency.
|
| 1080 |
*
|
| 1081 |
* Returns 0 if no errors are found, the number of errors in case the image is
|
| 1082 |
* detected as corrupted, and -errno when an internal error occurred.
|
| 1083 |
*/
|
| 1084 |
int qcow2_check_refcounts(BlockDriverState *bs, BdrvCheckResult *res)
|
| 1085 |
{
|
| 1086 |
BDRVQcowState *s = bs->opaque; |
| 1087 |
int64_t size; |
| 1088 |
int nb_clusters, refcount1, refcount2, i;
|
| 1089 |
QCowSnapshot *sn; |
| 1090 |
uint16_t *refcount_table; |
| 1091 |
int ret;
|
| 1092 |
|
| 1093 |
size = bdrv_getlength(bs->file); |
| 1094 |
nb_clusters = size_to_clusters(s, size); |
| 1095 |
refcount_table = qemu_mallocz(nb_clusters * sizeof(uint16_t));
|
| 1096 |
|
| 1097 |
/* header */
|
| 1098 |
inc_refcounts(bs, res, refcount_table, nb_clusters, |
| 1099 |
0, s->cluster_size);
|
| 1100 |
|
| 1101 |
/* current L1 table */
|
| 1102 |
ret = check_refcounts_l1(bs, res, refcount_table, nb_clusters, |
| 1103 |
s->l1_table_offset, s->l1_size, 1);
|
| 1104 |
if (ret < 0) { |
| 1105 |
goto fail;
|
| 1106 |
} |
| 1107 |
|
| 1108 |
/* snapshots */
|
| 1109 |
for(i = 0; i < s->nb_snapshots; i++) { |
| 1110 |
sn = s->snapshots + i; |
| 1111 |
ret = check_refcounts_l1(bs, res, refcount_table, nb_clusters, |
| 1112 |
sn->l1_table_offset, sn->l1_size, 0);
|
| 1113 |
if (ret < 0) { |
| 1114 |
goto fail;
|
| 1115 |
} |
| 1116 |
} |
| 1117 |
inc_refcounts(bs, res, refcount_table, nb_clusters, |
| 1118 |
s->snapshots_offset, s->snapshots_size); |
| 1119 |
|
| 1120 |
/* refcount data */
|
| 1121 |
inc_refcounts(bs, res, refcount_table, nb_clusters, |
| 1122 |
s->refcount_table_offset, |
| 1123 |
s->refcount_table_size * sizeof(uint64_t));
|
| 1124 |
|
| 1125 |
for(i = 0; i < s->refcount_table_size; i++) { |
| 1126 |
uint64_t offset, cluster; |
| 1127 |
offset = s->refcount_table[i]; |
| 1128 |
cluster = offset >> s->cluster_bits; |
| 1129 |
|
| 1130 |
/* Refcount blocks are cluster aligned */
|
| 1131 |
if (offset & (s->cluster_size - 1)) { |
| 1132 |
fprintf(stderr, "ERROR refcount block %d is not "
|
| 1133 |
"cluster aligned; refcount table entry corrupted\n", i);
|
| 1134 |
res->corruptions++; |
| 1135 |
continue;
|
| 1136 |
} |
| 1137 |
|
| 1138 |
if (cluster >= nb_clusters) {
|
| 1139 |
fprintf(stderr, "ERROR refcount block %d is outside image\n", i);
|
| 1140 |
res->corruptions++; |
| 1141 |
continue;
|
| 1142 |
} |
| 1143 |
|
| 1144 |
if (offset != 0) { |
| 1145 |
inc_refcounts(bs, res, refcount_table, nb_clusters, |
| 1146 |
offset, s->cluster_size); |
| 1147 |
if (refcount_table[cluster] != 1) { |
| 1148 |
fprintf(stderr, "ERROR refcount block %d refcount=%d\n",
|
| 1149 |
i, refcount_table[cluster]); |
| 1150 |
res->corruptions++; |
| 1151 |
} |
| 1152 |
} |
| 1153 |
} |
| 1154 |
|
| 1155 |
/* compare ref counts */
|
| 1156 |
for(i = 0; i < nb_clusters; i++) { |
| 1157 |
refcount1 = get_refcount(bs, i); |
| 1158 |
if (refcount1 < 0) { |
| 1159 |
fprintf(stderr, "Can't get refcount for cluster %d: %s\n",
|
| 1160 |
i, strerror(-refcount1)); |
| 1161 |
res->check_errors++; |
| 1162 |
continue;
|
| 1163 |
} |
| 1164 |
|
| 1165 |
refcount2 = refcount_table[i]; |
| 1166 |
if (refcount1 != refcount2) {
|
| 1167 |
fprintf(stderr, "%s cluster %d refcount=%d reference=%d\n",
|
| 1168 |
refcount1 < refcount2 ? "ERROR" : "Leaked", |
| 1169 |
i, refcount1, refcount2); |
| 1170 |
if (refcount1 < refcount2) {
|
| 1171 |
res->corruptions++; |
| 1172 |
} else {
|
| 1173 |
res->leaks++; |
| 1174 |
} |
| 1175 |
} |
| 1176 |
} |
| 1177 |
|
| 1178 |
ret = 0;
|
| 1179 |
|
| 1180 |
fail:
|
| 1181 |
qemu_free(refcount_table); |
| 1182 |
|
| 1183 |
return ret;
|
| 1184 |
} |
| 1185 |
|