This distinguishes between harmless leaks and real corruption. Hopefully users better understand what qemu-img check wants to tell them. Signed-off-by: Kevin Wolf <kwolf@redhat.com>
1203 lines
39 KiB
C
1203 lines
39 KiB
C
/*
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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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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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static int cache_refcount_updates = 0;
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static int write_refcount_block(BlockDriverState *bs)
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{
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BDRVQcowState *s = bs->opaque;
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size_t size = s->cluster_size;
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if (s->refcount_block_cache_offset == 0) {
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return 0;
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}
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BLKDBG_EVENT(bs->file, BLKDBG_REFBLOCK_UPDATE);
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if (bdrv_pwrite_sync(bs->file, s->refcount_block_cache_offset,
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s->refcount_block_cache, size) < 0)
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{
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return -EIO;
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}
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return 0;
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}
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/*********************************************************/
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/* refcount handling */
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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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s->refcount_block_cache = qemu_malloc(s->cluster_size);
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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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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_block_cache);
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qemu_free(s->refcount_table);
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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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{
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BDRVQcowState *s = bs->opaque;
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int ret;
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if (cache_refcount_updates) {
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ret = write_refcount_block(bs);
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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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BLKDBG_EVENT(bs->file, BLKDBG_REFBLOCK_LOAD);
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ret = bdrv_pread(bs->file, refcount_block_offset, s->refcount_block_cache,
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s->cluster_size);
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if (ret < 0) {
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return ret;
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}
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s->refcount_block_cache_offset = refcount_block_offset;
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return 0;
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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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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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if (refcount_block_offset != s->refcount_block_cache_offset) {
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/* better than nothing: return allocated if read error */
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ret = load_refcount_block(bs, refcount_block_offset);
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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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return be16_to_cpu(s->refcount_block_cache[block_index]);
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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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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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return refcount_table_clusters << (s->cluster_bits - 3);
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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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return (block_a == block_b);
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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 the offset of the refcount block on success or -errno in error case
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*/
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static int64_t alloc_refcount_block(BlockDriverState *bs, int64_t cluster_index)
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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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BLKDBG_EVENT(bs->file, BLKDBG_REFBLOCK_ALLOC);
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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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if (refcount_table_index < s->refcount_table_size) {
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uint64_t refcount_block_offset =
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s->refcount_table[refcount_table_index];
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/* If it's already there, we're done */
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if (refcount_block_offset) {
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if (refcount_block_offset != s->refcount_block_cache_offset) {
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ret = load_refcount_block(bs, refcount_block_offset);
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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_block_offset;
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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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if (cache_refcount_updates) {
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ret = write_refcount_block(bs);
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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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/* 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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#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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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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memset(s->refcount_block_cache, 0, s->cluster_size);
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s->refcount_block_cache_offset = new_block;
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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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s->refcount_block_cache[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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}
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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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memset(s->refcount_block_cache, 0, s->cluster_size);
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s->refcount_block_cache_offset = new_block;
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}
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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);
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ret = bdrv_pwrite_sync(bs->file, new_block, s->refcount_block_cache,
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s->cluster_size);
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if (ret < 0) {
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goto fail_block;
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}
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/* If the refcount table is big enough, just hook the block up there */
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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);
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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));
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if (ret < 0) {
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goto fail_block;
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}
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s->refcount_table[refcount_table_index] = new_block;
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return new_block;
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}
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/*
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* If we come here, we need to grow the refcount table. Again, a new
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* refcount table needs some space and we can't simply allocate to avoid
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* endless recursion.
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*
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* Therefore let's grab new refcount blocks at the end of the image, which
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* will describe themselves and the new refcount table. This way we can
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* reference them only in the new table and do the switch to the new
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* refcount table at once without producing an inconsistent state in
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* between.
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*/
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BLKDBG_EVENT(bs->file, BLKDBG_REFTABLE_GROW);
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/* Calculate the number of refcount blocks needed so far */
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uint64_t refcount_block_clusters = 1 << (s->cluster_bits - REFCOUNT_SHIFT);
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uint64_t blocks_used = (s->free_cluster_index +
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refcount_block_clusters - 1) / refcount_block_clusters;
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/* And now we need at least one block more for the new metadata */
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uint64_t table_size = next_refcount_table_size(s, blocks_used + 1);
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uint64_t last_table_size;
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uint64_t blocks_clusters;
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do {
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uint64_t table_clusters = size_to_clusters(s, table_size);
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blocks_clusters = 1 +
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((table_clusters + refcount_block_clusters - 1)
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/ refcount_block_clusters);
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uint64_t meta_clusters = table_clusters + blocks_clusters;
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last_table_size = table_size;
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table_size = next_refcount_table_size(s, blocks_used +
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((meta_clusters + refcount_block_clusters - 1)
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/ refcount_block_clusters));
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} while (last_table_size != table_size);
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#ifdef DEBUG_ALLOC2
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fprintf(stderr, "qcow2: Grow refcount table %" PRId32 " => %" PRId64 "\n",
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s->refcount_table_size, table_size);
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#endif
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/* Create the new refcount table and blocks */
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uint64_t meta_offset = (blocks_used * refcount_block_clusters) *
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s->cluster_size;
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uint64_t table_offset = meta_offset + blocks_clusters * s->cluster_size;
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uint16_t *new_blocks = qemu_mallocz(blocks_clusters * s->cluster_size);
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uint64_t *new_table = qemu_mallocz(table_size * sizeof(uint64_t));
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assert(meta_offset >= (s->free_cluster_index * s->cluster_size));
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/* Fill the new refcount table */
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memcpy(new_table, s->refcount_table,
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s->refcount_table_size * sizeof(uint64_t));
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new_table[refcount_table_index] = new_block;
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int i;
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for (i = 0; i < blocks_clusters; i++) {
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new_table[blocks_used + i] = meta_offset + (i * s->cluster_size);
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}
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/* Fill the refcount blocks */
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uint64_t table_clusters = size_to_clusters(s, table_size * sizeof(uint64_t));
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int block = 0;
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for (i = 0; i < table_clusters + blocks_clusters; i++) {
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new_blocks[block++] = cpu_to_be16(1);
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}
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/* Write refcount blocks to disk */
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BLKDBG_EVENT(bs->file, BLKDBG_REFBLOCK_ALLOC_WRITE_BLOCKS);
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ret = bdrv_pwrite_sync(bs->file, meta_offset, new_blocks,
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blocks_clusters * s->cluster_size);
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qemu_free(new_blocks);
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if (ret < 0) {
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goto fail_table;
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}
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/* Write refcount table to disk */
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for(i = 0; i < table_size; i++) {
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cpu_to_be64s(&new_table[i]);
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}
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BLKDBG_EVENT(bs->file, BLKDBG_REFBLOCK_ALLOC_WRITE_TABLE);
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ret = bdrv_pwrite_sync(bs->file, table_offset, new_table,
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table_size * sizeof(uint64_t));
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if (ret < 0) {
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goto fail_table;
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}
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for(i = 0; i < table_size; i++) {
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cpu_to_be64s(&new_table[i]);
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}
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/* Hook up the new refcount table in the qcow2 header */
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uint8_t data[12];
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cpu_to_be64w((uint64_t*)data, table_offset);
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cpu_to_be32w((uint32_t*)(data + 8), table_clusters);
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BLKDBG_EVENT(bs->file, BLKDBG_REFBLOCK_ALLOC_SWITCH_TABLE);
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ret = bdrv_pwrite_sync(bs->file, offsetof(QCowHeader, refcount_table_offset),
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data, sizeof(data));
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if (ret < 0) {
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goto fail_table;
|
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}
|
|
|
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/* And switch it in memory */
|
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uint64_t old_table_offset = s->refcount_table_offset;
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uint64_t old_table_size = s->refcount_table_size;
|
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|
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qemu_free(s->refcount_table);
|
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s->refcount_table = new_table;
|
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s->refcount_table_size = table_size;
|
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s->refcount_table_offset = table_offset;
|
|
|
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/* Free old table. Remember, we must not change free_cluster_index */
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uint64_t old_free_cluster_index = s->free_cluster_index;
|
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qcow2_free_clusters(bs, old_table_offset, old_table_size * sizeof(uint64_t));
|
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s->free_cluster_index = old_free_cluster_index;
|
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|
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ret = load_refcount_block(bs, new_block);
|
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if (ret < 0) {
|
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goto fail_block;
|
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}
|
|
|
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return new_block;
|
|
|
|
fail_table:
|
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qemu_free(new_table);
|
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fail_block:
|
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s->refcount_block_cache_offset = 0;
|
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return ret;
|
|
}
|
|
|
|
#define REFCOUNTS_PER_SECTOR (512 >> REFCOUNT_SHIFT)
|
|
static int write_refcount_block_entries(BlockDriverState *bs,
|
|
int64_t refcount_block_offset, int first_index, int last_index)
|
|
{
|
|
BDRVQcowState *s = bs->opaque;
|
|
size_t size;
|
|
int ret;
|
|
|
|
if (cache_refcount_updates) {
|
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return 0;
|
|
}
|
|
|
|
if (first_index < 0) {
|
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return 0;
|
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}
|
|
|
|
first_index &= ~(REFCOUNTS_PER_SECTOR - 1);
|
|
last_index = (last_index + REFCOUNTS_PER_SECTOR)
|
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& ~(REFCOUNTS_PER_SECTOR - 1);
|
|
|
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size = (last_index - first_index) << REFCOUNT_SHIFT;
|
|
|
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BLKDBG_EVENT(bs->file, BLKDBG_REFBLOCK_UPDATE_PART);
|
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ret = bdrv_pwrite_sync(bs->file,
|
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refcount_block_offset + (first_index << REFCOUNT_SHIFT),
|
|
&s->refcount_block_cache[first_index], size);
|
|
if (ret < 0) {
|
|
return ret;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
/* XXX: cache several refcount block clusters ? */
|
|
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) {
|
|
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;
|
|
cluster_offset += s->cluster_size)
|
|
{
|
|
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;
|
|
table_index = cluster_index >> (s->cluster_bits - REFCOUNT_SHIFT);
|
|
if ((old_table_index >= 0) && (table_index != old_table_index)) {
|
|
|
|
ret = write_refcount_block_entries(bs, refcount_block_offset,
|
|
first_index, last_index);
|
|
if (ret < 0) {
|
|
return ret;
|
|
}
|
|
|
|
first_index = -1;
|
|
last_index = -1;
|
|
}
|
|
|
|
/* Load the refcount block and allocate it if needed */
|
|
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 &
|
|
((1 << (s->cluster_bits - REFCOUNT_SHIFT)) - 1);
|
|
if (first_index == -1 || block_index < first_index) {
|
|
first_index = block_index;
|
|
}
|
|
if (block_index > last_index) {
|
|
last_index = block_index;
|
|
}
|
|
|
|
refcount = be16_to_cpu(s->refcount_block_cache[block_index]);
|
|
refcount += addend;
|
|
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) {
|
|
int wret;
|
|
wret = write_refcount_block_entries(bs, refcount_block_offset,
|
|
first_index, last_index);
|
|
if (wret < 0) {
|
|
return ret < 0 ? ret : wret;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* 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;
|
|
}
|
|
|
|
/*
|
|
* Increases or decreases the refcount of a given cluster by one.
|
|
* addend must be 1 or -1.
|
|
*
|
|
* If the return value is non-negative, it is the new refcount of the cluster.
|
|
* If it is negative, it is -errno and indicates an error.
|
|
*/
|
|
static int update_cluster_refcount(BlockDriverState *bs,
|
|
int64_t cluster_index,
|
|
int addend)
|
|
{
|
|
BDRVQcowState *s = bs->opaque;
|
|
int ret;
|
|
|
|
ret = update_refcount(bs, cluster_index << s->cluster_bits, 1, addend);
|
|
if (ret < 0) {
|
|
return ret;
|
|
}
|
|
|
|
return get_refcount(bs, cluster_index);
|
|
}
|
|
|
|
|
|
|
|
/*********************************************************/
|
|
/* cluster allocation functions */
|
|
|
|
|
|
|
|
/* return < 0 if error */
|
|
static int64_t alloc_clusters_noref(BlockDriverState *bs, int64_t size)
|
|
{
|
|
BDRVQcowState *s = bs->opaque;
|
|
int i, nb_clusters, refcount;
|
|
|
|
nb_clusters = size_to_clusters(s, size);
|
|
retry:
|
|
for(i = 0; i < nb_clusters; i++) {
|
|
int64_t next_cluster_index = s->free_cluster_index++;
|
|
refcount = get_refcount(bs, next_cluster_index);
|
|
|
|
if (refcount < 0) {
|
|
return refcount;
|
|
} else if (refcount != 0) {
|
|
goto retry;
|
|
}
|
|
}
|
|
#ifdef DEBUG_ALLOC2
|
|
printf("alloc_clusters: size=%" PRId64 " -> %" PRId64 "\n",
|
|
size,
|
|
(s->free_cluster_index - nb_clusters) << s->cluster_bits);
|
|
#endif
|
|
return (s->free_cluster_index - nb_clusters) << s->cluster_bits;
|
|
}
|
|
|
|
int64_t qcow2_alloc_clusters(BlockDriverState *bs, int64_t size)
|
|
{
|
|
int64_t offset;
|
|
int ret;
|
|
|
|
BLKDBG_EVENT(bs->file, BLKDBG_CLUSTER_ALLOC);
|
|
offset = alloc_clusters_noref(bs, size);
|
|
if (offset < 0) {
|
|
return offset;
|
|
}
|
|
|
|
ret = update_refcount(bs, offset, size, 1);
|
|
if (ret < 0) {
|
|
return ret;
|
|
}
|
|
return offset;
|
|
}
|
|
|
|
/* only used to allocate compressed sectors. We try to allocate
|
|
contiguous sectors. size must be <= cluster_size */
|
|
int64_t qcow2_alloc_bytes(BlockDriverState *bs, int size)
|
|
{
|
|
BDRVQcowState *s = bs->opaque;
|
|
int64_t offset, cluster_offset;
|
|
int free_in_cluster;
|
|
|
|
BLKDBG_EVENT(bs->file, BLKDBG_CLUSTER_ALLOC_BYTES);
|
|
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 -
|
|
(s->free_byte_offset & (s->cluster_size - 1));
|
|
if (size <= free_in_cluster) {
|
|
/* enough space in current cluster */
|
|
offset = s->free_byte_offset;
|
|
s->free_byte_offset += size;
|
|
free_in_cluster -= size;
|
|
if (free_in_cluster == 0)
|
|
s->free_byte_offset = 0;
|
|
if ((offset & (s->cluster_size - 1)) != 0)
|
|
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 */
|
|
offset = s->free_byte_offset;
|
|
update_cluster_refcount(bs, offset >> s->cluster_bits, 1);
|
|
s->free_byte_offset += size;
|
|
} else {
|
|
s->free_byte_offset = offset;
|
|
goto redo;
|
|
}
|
|
}
|
|
return offset;
|
|
}
|
|
|
|
void qcow2_free_clusters(BlockDriverState *bs,
|
|
int64_t offset, int64_t size)
|
|
{
|
|
int ret;
|
|
|
|
BLKDBG_EVENT(bs->file, BLKDBG_CLUSTER_FREE);
|
|
ret = update_refcount(bs, offset, size, -1);
|
|
if (ret < 0) {
|
|
fprintf(stderr, "qcow2_free_clusters failed: %s\n", strerror(-ret));
|
|
/* TODO Remember the clusters to free them later and avoid leaking */
|
|
}
|
|
}
|
|
|
|
/*
|
|
* free_any_clusters
|
|
*
|
|
* free clusters according to its type: compressed or not
|
|
*
|
|
*/
|
|
|
|
void qcow2_free_any_clusters(BlockDriverState *bs,
|
|
uint64_t cluster_offset, int nb_clusters)
|
|
{
|
|
BDRVQcowState *s = bs->opaque;
|
|
|
|
/* free the cluster */
|
|
|
|
if (cluster_offset & QCOW_OFLAG_COMPRESSED) {
|
|
int nb_csectors;
|
|
nb_csectors = ((cluster_offset >> s->csize_shift) &
|
|
s->csize_mask) + 1;
|
|
qcow2_free_clusters(bs,
|
|
(cluster_offset & s->cluster_offset_mask) & ~511,
|
|
nb_csectors * 512);
|
|
return;
|
|
}
|
|
|
|
qcow2_free_clusters(bs, cluster_offset, nb_clusters << s->cluster_bits);
|
|
|
|
return;
|
|
}
|
|
|
|
|
|
|
|
/*********************************************************/
|
|
/* snapshots and image creation */
|
|
|
|
|
|
|
|
void qcow2_create_refcount_update(QCowCreateState *s, int64_t offset,
|
|
int64_t size)
|
|
{
|
|
int refcount;
|
|
int64_t start, last, cluster_offset;
|
|
uint16_t *p;
|
|
|
|
start = offset & ~(s->cluster_size - 1);
|
|
last = (offset + size - 1) & ~(s->cluster_size - 1);
|
|
for(cluster_offset = start; cluster_offset <= last;
|
|
cluster_offset += s->cluster_size) {
|
|
p = &s->refcount_block[cluster_offset >> s->cluster_bits];
|
|
refcount = be16_to_cpu(*p);
|
|
refcount++;
|
|
*p = cpu_to_be16(refcount);
|
|
}
|
|
}
|
|
|
|
/* update the refcounts of snapshots and the copied flag */
|
|
int qcow2_update_snapshot_refcount(BlockDriverState *bs,
|
|
int64_t l1_table_offset, int l1_size, int addend)
|
|
{
|
|
BDRVQcowState *s = bs->opaque;
|
|
uint64_t *l1_table, *l2_table, l2_offset, offset, l1_size2, l1_allocated;
|
|
int64_t old_offset, old_l2_offset;
|
|
int l2_size, i, j, l1_modified, l2_modified, nb_csectors, refcount;
|
|
|
|
qcow2_l2_cache_reset(bs);
|
|
cache_refcount_updates = 1;
|
|
|
|
l2_table = NULL;
|
|
l1_table = NULL;
|
|
l1_size2 = l1_size * sizeof(uint64_t);
|
|
if (l1_table_offset != s->l1_table_offset) {
|
|
if (l1_size2 != 0) {
|
|
l1_table = qemu_mallocz(align_offset(l1_size2, 512));
|
|
} else {
|
|
l1_table = NULL;
|
|
}
|
|
l1_allocated = 1;
|
|
if (bdrv_pread(bs->file, l1_table_offset,
|
|
l1_table, l1_size2) != l1_size2)
|
|
goto fail;
|
|
for(i = 0;i < l1_size; i++)
|
|
be64_to_cpus(&l1_table[i]);
|
|
} else {
|
|
assert(l1_size == s->l1_size);
|
|
l1_table = s->l1_table;
|
|
l1_allocated = 0;
|
|
}
|
|
|
|
l2_size = s->l2_size * sizeof(uint64_t);
|
|
l2_table = qemu_malloc(l2_size);
|
|
l1_modified = 0;
|
|
for(i = 0; i < l1_size; i++) {
|
|
l2_offset = l1_table[i];
|
|
if (l2_offset) {
|
|
old_l2_offset = l2_offset;
|
|
l2_offset &= ~QCOW_OFLAG_COPIED;
|
|
l2_modified = 0;
|
|
if (bdrv_pread(bs->file, l2_offset, l2_table, l2_size) != l2_size)
|
|
goto fail;
|
|
for(j = 0; j < s->l2_size; j++) {
|
|
offset = be64_to_cpu(l2_table[j]);
|
|
if (offset != 0) {
|
|
old_offset = offset;
|
|
offset &= ~QCOW_OFLAG_COPIED;
|
|
if (offset & QCOW_OFLAG_COMPRESSED) {
|
|
nb_csectors = ((offset >> s->csize_shift) &
|
|
s->csize_mask) + 1;
|
|
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 {
|
|
if (addend != 0) {
|
|
refcount = update_cluster_refcount(bs, offset >> s->cluster_bits, addend);
|
|
} else {
|
|
refcount = get_refcount(bs, offset >> s->cluster_bits);
|
|
}
|
|
|
|
if (refcount < 0) {
|
|
goto fail;
|
|
}
|
|
}
|
|
|
|
if (refcount == 1) {
|
|
offset |= QCOW_OFLAG_COPIED;
|
|
}
|
|
if (offset != old_offset) {
|
|
l2_table[j] = cpu_to_be64(offset);
|
|
l2_modified = 1;
|
|
}
|
|
}
|
|
}
|
|
if (l2_modified) {
|
|
if (bdrv_pwrite_sync(bs->file,
|
|
l2_offset, l2_table, l2_size) < 0)
|
|
goto fail;
|
|
}
|
|
|
|
if (addend != 0) {
|
|
refcount = update_cluster_refcount(bs, l2_offset >> s->cluster_bits, addend);
|
|
} else {
|
|
refcount = get_refcount(bs, l2_offset >> s->cluster_bits);
|
|
}
|
|
if (refcount < 0) {
|
|
goto fail;
|
|
} else if (refcount == 1) {
|
|
l2_offset |= QCOW_OFLAG_COPIED;
|
|
}
|
|
if (l2_offset != old_l2_offset) {
|
|
l1_table[i] = l2_offset;
|
|
l1_modified = 1;
|
|
}
|
|
}
|
|
}
|
|
if (l1_modified) {
|
|
for(i = 0; i < l1_size; i++)
|
|
cpu_to_be64s(&l1_table[i]);
|
|
if (bdrv_pwrite_sync(bs->file, l1_table_offset, l1_table,
|
|
l1_size2) < 0)
|
|
goto fail;
|
|
for(i = 0; i < l1_size; i++)
|
|
be64_to_cpus(&l1_table[i]);
|
|
}
|
|
if (l1_allocated)
|
|
qemu_free(l1_table);
|
|
qemu_free(l2_table);
|
|
cache_refcount_updates = 0;
|
|
write_refcount_block(bs);
|
|
return 0;
|
|
fail:
|
|
if (l1_allocated)
|
|
qemu_free(l1_table);
|
|
qemu_free(l2_table);
|
|
cache_refcount_updates = 0;
|
|
write_refcount_block(bs);
|
|
return -EIO;
|
|
}
|
|
|
|
|
|
|
|
|
|
/*********************************************************/
|
|
/* refcount checking functions */
|
|
|
|
|
|
|
|
/*
|
|
* Increases the refcount for a range of clusters in a given refcount table.
|
|
* This is used to construct a temporary refcount table out of L1 and L2 tables
|
|
* which can be compared the the refcount table saved in the image.
|
|
*
|
|
* Modifies the number of errors in res.
|
|
*/
|
|
static void inc_refcounts(BlockDriverState *bs,
|
|
BdrvCheckResult *res,
|
|
uint16_t *refcount_table,
|
|
int refcount_table_size,
|
|
int64_t offset, int64_t size)
|
|
{
|
|
BDRVQcowState *s = bs->opaque;
|
|
int64_t start, last, cluster_offset;
|
|
int k;
|
|
|
|
if (size <= 0)
|
|
return;
|
|
|
|
start = offset & ~(s->cluster_size - 1);
|
|
last = (offset + size - 1) & ~(s->cluster_size - 1);
|
|
for(cluster_offset = start; cluster_offset <= last;
|
|
cluster_offset += s->cluster_size) {
|
|
k = cluster_offset >> s->cluster_bits;
|
|
if (k < 0) {
|
|
fprintf(stderr, "ERROR: invalid cluster offset=0x%" PRIx64 "\n",
|
|
cluster_offset);
|
|
res->corruptions++;
|
|
} else if (k >= refcount_table_size) {
|
|
fprintf(stderr, "Warning: cluster offset=0x%" PRIx64 " is after "
|
|
"the end of the image file, can't properly check refcounts.\n",
|
|
cluster_offset);
|
|
res->check_errors++;
|
|
} else {
|
|
if (++refcount_table[k] == 0) {
|
|
fprintf(stderr, "ERROR: overflow cluster offset=0x%" PRIx64
|
|
"\n", cluster_offset);
|
|
res->corruptions++;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Increases the refcount in the given refcount table for the all clusters
|
|
* referenced in the L2 table. While doing so, performs some checks on L2
|
|
* entries.
|
|
*
|
|
* Returns the number of errors found by the checks or -errno if an internal
|
|
* error occurred.
|
|
*/
|
|
static int check_refcounts_l2(BlockDriverState *bs, BdrvCheckResult *res,
|
|
uint16_t *refcount_table, int refcount_table_size, int64_t l2_offset,
|
|
int check_copied)
|
|
{
|
|
BDRVQcowState *s = bs->opaque;
|
|
uint64_t *l2_table, offset;
|
|
int i, l2_size, nb_csectors, refcount;
|
|
|
|
/* Read L2 table from disk */
|
|
l2_size = s->l2_size * sizeof(uint64_t);
|
|
l2_table = qemu_malloc(l2_size);
|
|
|
|
if (bdrv_pread(bs->file, l2_offset, l2_table, l2_size) != l2_size)
|
|
goto fail;
|
|
|
|
/* Do the actual checks */
|
|
for(i = 0; i < s->l2_size; i++) {
|
|
offset = be64_to_cpu(l2_table[i]);
|
|
if (offset != 0) {
|
|
if (offset & QCOW_OFLAG_COMPRESSED) {
|
|
/* Compressed clusters don't have QCOW_OFLAG_COPIED */
|
|
if (offset & QCOW_OFLAG_COPIED) {
|
|
fprintf(stderr, "ERROR: cluster %" PRId64 ": "
|
|
"copied flag must never be set for compressed "
|
|
"clusters\n", offset >> s->cluster_bits);
|
|
offset &= ~QCOW_OFLAG_COPIED;
|
|
res->corruptions++;
|
|
}
|
|
|
|
/* Mark cluster as used */
|
|
nb_csectors = ((offset >> s->csize_shift) &
|
|
s->csize_mask) + 1;
|
|
offset &= s->cluster_offset_mask;
|
|
inc_refcounts(bs, res, refcount_table, refcount_table_size,
|
|
offset & ~511, nb_csectors * 512);
|
|
} else {
|
|
/* QCOW_OFLAG_COPIED must be set iff refcount == 1 */
|
|
if (check_copied) {
|
|
uint64_t entry = offset;
|
|
offset &= ~QCOW_OFLAG_COPIED;
|
|
refcount = get_refcount(bs, offset >> s->cluster_bits);
|
|
if (refcount < 0) {
|
|
fprintf(stderr, "Can't get refcount for offset %"
|
|
PRIx64 ": %s\n", entry, strerror(-refcount));
|
|
goto fail;
|
|
}
|
|
if ((refcount == 1) != ((entry & QCOW_OFLAG_COPIED) != 0)) {
|
|
fprintf(stderr, "ERROR OFLAG_COPIED: offset=%"
|
|
PRIx64 " refcount=%d\n", entry, refcount);
|
|
res->corruptions++;
|
|
}
|
|
}
|
|
|
|
/* Mark cluster as used */
|
|
offset &= ~QCOW_OFLAG_COPIED;
|
|
inc_refcounts(bs, res, refcount_table,refcount_table_size,
|
|
offset, s->cluster_size);
|
|
|
|
/* Correct offsets are cluster aligned */
|
|
if (offset & (s->cluster_size - 1)) {
|
|
fprintf(stderr, "ERROR offset=%" PRIx64 ": Cluster is not "
|
|
"properly aligned; L2 entry corrupted.\n", offset);
|
|
res->corruptions++;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
qemu_free(l2_table);
|
|
return 0;
|
|
|
|
fail:
|
|
fprintf(stderr, "ERROR: I/O error in check_refcounts_l2\n");
|
|
qemu_free(l2_table);
|
|
return -EIO;
|
|
}
|
|
|
|
/*
|
|
* Increases the refcount for the L1 table, its L2 tables and all referenced
|
|
* clusters in the given refcount table. While doing so, performs some checks
|
|
* on L1 and L2 entries.
|
|
*
|
|
* Returns the number of errors found by the checks or -errno if an internal
|
|
* error occurred.
|
|
*/
|
|
static int check_refcounts_l1(BlockDriverState *bs,
|
|
BdrvCheckResult *res,
|
|
uint16_t *refcount_table,
|
|
int refcount_table_size,
|
|
int64_t l1_table_offset, int l1_size,
|
|
int check_copied)
|
|
{
|
|
BDRVQcowState *s = bs->opaque;
|
|
uint64_t *l1_table, l2_offset, l1_size2;
|
|
int i, refcount, ret;
|
|
|
|
l1_size2 = l1_size * sizeof(uint64_t);
|
|
|
|
/* Mark L1 table as used */
|
|
inc_refcounts(bs, res, refcount_table, refcount_table_size,
|
|
l1_table_offset, l1_size2);
|
|
|
|
/* Read L1 table entries from disk */
|
|
if (l1_size2 == 0) {
|
|
l1_table = NULL;
|
|
} else {
|
|
l1_table = qemu_malloc(l1_size2);
|
|
if (bdrv_pread(bs->file, l1_table_offset,
|
|
l1_table, l1_size2) != l1_size2)
|
|
goto fail;
|
|
for(i = 0;i < l1_size; i++)
|
|
be64_to_cpus(&l1_table[i]);
|
|
}
|
|
|
|
/* Do the actual checks */
|
|
for(i = 0; i < l1_size; i++) {
|
|
l2_offset = l1_table[i];
|
|
if (l2_offset) {
|
|
/* QCOW_OFLAG_COPIED must be set iff refcount == 1 */
|
|
if (check_copied) {
|
|
refcount = get_refcount(bs, (l2_offset & ~QCOW_OFLAG_COPIED)
|
|
>> s->cluster_bits);
|
|
if (refcount < 0) {
|
|
fprintf(stderr, "Can't get refcount for l2_offset %"
|
|
PRIx64 ": %s\n", l2_offset, strerror(-refcount));
|
|
goto fail;
|
|
}
|
|
if ((refcount == 1) != ((l2_offset & QCOW_OFLAG_COPIED) != 0)) {
|
|
fprintf(stderr, "ERROR OFLAG_COPIED: l2_offset=%" PRIx64
|
|
" refcount=%d\n", l2_offset, refcount);
|
|
res->corruptions++;
|
|
}
|
|
}
|
|
|
|
/* Mark L2 table as used */
|
|
l2_offset &= ~QCOW_OFLAG_COPIED;
|
|
inc_refcounts(bs, res, refcount_table, refcount_table_size,
|
|
l2_offset, s->cluster_size);
|
|
|
|
/* L2 tables are cluster aligned */
|
|
if (l2_offset & (s->cluster_size - 1)) {
|
|
fprintf(stderr, "ERROR l2_offset=%" PRIx64 ": Table is not "
|
|
"cluster aligned; L1 entry corrupted\n", l2_offset);
|
|
res->corruptions++;
|
|
}
|
|
|
|
/* Process and check L2 entries */
|
|
ret = check_refcounts_l2(bs, res, refcount_table,
|
|
refcount_table_size, l2_offset, check_copied);
|
|
if (ret < 0) {
|
|
goto fail;
|
|
}
|
|
}
|
|
}
|
|
qemu_free(l1_table);
|
|
return 0;
|
|
|
|
fail:
|
|
fprintf(stderr, "ERROR: I/O error in check_refcounts_l1\n");
|
|
res->check_errors++;
|
|
qemu_free(l1_table);
|
|
return -EIO;
|
|
}
|
|
|
|
/*
|
|
* Checks an image for refcount consistency.
|
|
*
|
|
* Returns 0 if no errors are found, the number of errors in case the image is
|
|
* detected as corrupted, and -errno when an internal error occured.
|
|
*/
|
|
int qcow2_check_refcounts(BlockDriverState *bs, BdrvCheckResult *res)
|
|
{
|
|
BDRVQcowState *s = bs->opaque;
|
|
int64_t size;
|
|
int nb_clusters, refcount1, refcount2, i;
|
|
QCowSnapshot *sn;
|
|
uint16_t *refcount_table;
|
|
int ret;
|
|
|
|
size = bdrv_getlength(bs->file);
|
|
nb_clusters = size_to_clusters(s, size);
|
|
refcount_table = qemu_mallocz(nb_clusters * sizeof(uint16_t));
|
|
|
|
/* header */
|
|
inc_refcounts(bs, res, refcount_table, nb_clusters,
|
|
0, s->cluster_size);
|
|
|
|
/* current L1 table */
|
|
ret = check_refcounts_l1(bs, res, refcount_table, nb_clusters,
|
|
s->l1_table_offset, s->l1_size, 1);
|
|
if (ret < 0) {
|
|
return ret;
|
|
}
|
|
|
|
/* snapshots */
|
|
for(i = 0; i < s->nb_snapshots; i++) {
|
|
sn = s->snapshots + i;
|
|
ret = check_refcounts_l1(bs, res, refcount_table, nb_clusters,
|
|
sn->l1_table_offset, sn->l1_size, 0);
|
|
if (ret < 0) {
|
|
return ret;
|
|
}
|
|
}
|
|
inc_refcounts(bs, res, refcount_table, nb_clusters,
|
|
s->snapshots_offset, s->snapshots_size);
|
|
|
|
/* refcount data */
|
|
inc_refcounts(bs, res, refcount_table, nb_clusters,
|
|
s->refcount_table_offset,
|
|
s->refcount_table_size * sizeof(uint64_t));
|
|
|
|
for(i = 0; i < s->refcount_table_size; i++) {
|
|
uint64_t offset, cluster;
|
|
offset = s->refcount_table[i];
|
|
cluster = offset >> s->cluster_bits;
|
|
|
|
/* Refcount blocks are cluster aligned */
|
|
if (offset & (s->cluster_size - 1)) {
|
|
fprintf(stderr, "ERROR refcount block %d is not "
|
|
"cluster aligned; refcount table entry corrupted\n", i);
|
|
res->corruptions++;
|
|
continue;
|
|
}
|
|
|
|
if (cluster >= nb_clusters) {
|
|
fprintf(stderr, "ERROR refcount block %d is outside image\n", i);
|
|
res->corruptions++;
|
|
continue;
|
|
}
|
|
|
|
if (offset != 0) {
|
|
inc_refcounts(bs, res, refcount_table, nb_clusters,
|
|
offset, s->cluster_size);
|
|
if (refcount_table[cluster] != 1) {
|
|
fprintf(stderr, "ERROR refcount block %d refcount=%d\n",
|
|
i, refcount_table[cluster]);
|
|
res->corruptions++;
|
|
}
|
|
}
|
|
}
|
|
|
|
/* compare ref counts */
|
|
for(i = 0; i < nb_clusters; i++) {
|
|
refcount1 = get_refcount(bs, i);
|
|
if (refcount1 < 0) {
|
|
fprintf(stderr, "Can't get refcount for cluster %d: %s\n",
|
|
i, strerror(-refcount1));
|
|
res->check_errors++;
|
|
continue;
|
|
}
|
|
|
|
refcount2 = refcount_table[i];
|
|
if (refcount1 != refcount2) {
|
|
fprintf(stderr, "%s cluster %d refcount=%d reference=%d\n",
|
|
refcount1 < refcount2 ? "ERROR" : "Leaked",
|
|
i, refcount1, refcount2);
|
|
if (refcount1 < refcount2) {
|
|
res->corruptions++;
|
|
} else {
|
|
res->leaks++;
|
|
}
|
|
}
|
|
}
|
|
|
|
qemu_free(refcount_table);
|
|
|
|
return 0;
|
|
}
|
|
|