root / block / qcow2-refcount.c @ afa50193
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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/block_int.h" |
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#include "block/qcow2.h" |
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#include "qemu/range.h" |
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#include "qapi/qmp/types.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, enum qcow2_discard_type type); |
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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 = g_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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} |
60 |
|
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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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g_free(s->refcount_table); |
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} |
66 |
|
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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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} |
81 |
|
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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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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]; |
100 |
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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} |
108 |
|
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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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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)); |
132 |
|
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while (min_clusters > refcount_table_clusters) {
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refcount_table_clusters = (refcount_table_clusters * 3 + 1) / 2; |
135 |
} |
136 |
|
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return refcount_table_clusters << (s->cluster_bits - 3); |
138 |
} |
139 |
|
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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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/*
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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, |
158 |
int64_t cluster_index, uint16_t **refcount_block) |
159 |
{ |
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BDRVQcowState *s = bs->opaque; |
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unsigned int refcount_table_index; |
162 |
int ret;
|
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|
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BLKDBG_EVENT(bs->file, BLKDBG_REFBLOCK_ALLOC); |
165 |
|
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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); |
168 |
|
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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] & REFT_OFFSET_MASK; |
173 |
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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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} |
179 |
} |
180 |
|
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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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202 |
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*refcount_block = NULL;
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/* We write to the refcount table, so we might depend on L2 tables */
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ret = qcow2_cache_flush(bs, s->l2_table_cache); |
207 |
if (ret < 0) { |
208 |
return ret;
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209 |
} |
210 |
|
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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); |
213 |
if (new_block < 0) { |
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return new_block;
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} |
216 |
|
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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); |
221 |
#endif
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222 |
|
223 |
if (in_same_refcount_block(s, new_block, cluster_index << s->cluster_bits)) {
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224 |
/* Zero the new refcount block before updating it */
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225 |
ret = qcow2_cache_get_empty(bs, s->refcount_block_cache, new_block, |
226 |
(void**) refcount_block);
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227 |
if (ret < 0) { |
228 |
goto fail_block;
|
229 |
} |
230 |
|
231 |
memset(*refcount_block, 0, s->cluster_size);
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232 |
|
233 |
/* 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); |
236 |
(*refcount_block)[block_index] = cpu_to_be16(1);
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} else {
|
238 |
/* 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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240 |
ret = update_refcount(bs, new_block, s->cluster_size, 1,
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QCOW2_DISCARD_NEVER); |
242 |
if (ret < 0) { |
243 |
goto fail_block;
|
244 |
} |
245 |
|
246 |
ret = qcow2_cache_flush(bs, s->refcount_block_cache); |
247 |
if (ret < 0) { |
248 |
goto fail_block;
|
249 |
} |
250 |
|
251 |
/* Initialize the new refcount block only after updating its refcount,
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252 |
* update_refcount uses the refcount cache itself */
|
253 |
ret = qcow2_cache_get_empty(bs, s->refcount_block_cache, new_block, |
254 |
(void**) refcount_block);
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255 |
if (ret < 0) { |
256 |
goto fail_block;
|
257 |
} |
258 |
|
259 |
memset(*refcount_block, 0, s->cluster_size);
|
260 |
} |
261 |
|
262 |
/* Now the new refcount block needs to be written to disk */
|
263 |
BLKDBG_EVENT(bs->file, BLKDBG_REFBLOCK_ALLOC_WRITE); |
264 |
qcow2_cache_entry_mark_dirty(s->refcount_block_cache, *refcount_block); |
265 |
ret = qcow2_cache_flush(bs, s->refcount_block_cache); |
266 |
if (ret < 0) { |
267 |
goto fail_block;
|
268 |
} |
269 |
|
270 |
/* If the refcount table is big enough, just hook the block up there */
|
271 |
if (refcount_table_index < s->refcount_table_size) {
|
272 |
uint64_t data64 = cpu_to_be64(new_block); |
273 |
BLKDBG_EVENT(bs->file, BLKDBG_REFBLOCK_ALLOC_HOOKUP); |
274 |
ret = bdrv_pwrite_sync(bs->file, |
275 |
s->refcount_table_offset + refcount_table_index * sizeof(uint64_t),
|
276 |
&data64, sizeof(data64));
|
277 |
if (ret < 0) { |
278 |
goto fail_block;
|
279 |
} |
280 |
|
281 |
s->refcount_table[refcount_table_index] = new_block; |
282 |
return 0; |
283 |
} |
284 |
|
285 |
ret = qcow2_cache_put(bs, s->refcount_block_cache, (void**) refcount_block);
|
286 |
if (ret < 0) { |
287 |
goto fail_block;
|
288 |
} |
289 |
|
290 |
/*
|
291 |
* If we come here, we need to grow the refcount table. Again, a new
|
292 |
* refcount table needs some space and we can't simply allocate to avoid
|
293 |
* endless recursion.
|
294 |
*
|
295 |
* Therefore let's grab new refcount blocks at the end of the image, which
|
296 |
* will describe themselves and the new refcount table. This way we can
|
297 |
* reference them only in the new table and do the switch to the new
|
298 |
* refcount table at once without producing an inconsistent state in
|
299 |
* between.
|
300 |
*/
|
301 |
BLKDBG_EVENT(bs->file, BLKDBG_REFTABLE_GROW); |
302 |
|
303 |
/* Calculate the number of refcount blocks needed so far */
|
304 |
uint64_t refcount_block_clusters = 1 << (s->cluster_bits - REFCOUNT_SHIFT);
|
305 |
uint64_t blocks_used = (s->free_cluster_index + |
306 |
refcount_block_clusters - 1) / refcount_block_clusters;
|
307 |
|
308 |
/* And now we need at least one block more for the new metadata */
|
309 |
uint64_t table_size = next_refcount_table_size(s, blocks_used + 1);
|
310 |
uint64_t last_table_size; |
311 |
uint64_t blocks_clusters; |
312 |
do {
|
313 |
uint64_t table_clusters = |
314 |
size_to_clusters(s, table_size * sizeof(uint64_t));
|
315 |
blocks_clusters = 1 +
|
316 |
((table_clusters + refcount_block_clusters - 1)
|
317 |
/ refcount_block_clusters); |
318 |
uint64_t meta_clusters = table_clusters + blocks_clusters; |
319 |
|
320 |
last_table_size = table_size; |
321 |
table_size = next_refcount_table_size(s, blocks_used + |
322 |
((meta_clusters + refcount_block_clusters - 1)
|
323 |
/ refcount_block_clusters)); |
324 |
|
325 |
} while (last_table_size != table_size);
|
326 |
|
327 |
#ifdef DEBUG_ALLOC2
|
328 |
fprintf(stderr, "qcow2: Grow refcount table %" PRId32 " => %" PRId64 "\n", |
329 |
s->refcount_table_size, table_size); |
330 |
#endif
|
331 |
|
332 |
/* Create the new refcount table and blocks */
|
333 |
uint64_t meta_offset = (blocks_used * refcount_block_clusters) * |
334 |
s->cluster_size; |
335 |
uint64_t table_offset = meta_offset + blocks_clusters * s->cluster_size; |
336 |
uint16_t *new_blocks = g_malloc0(blocks_clusters * s->cluster_size); |
337 |
uint64_t *new_table = g_malloc0(table_size * sizeof(uint64_t));
|
338 |
|
339 |
assert(meta_offset >= (s->free_cluster_index * s->cluster_size)); |
340 |
|
341 |
/* Fill the new refcount table */
|
342 |
memcpy(new_table, s->refcount_table, |
343 |
s->refcount_table_size * sizeof(uint64_t));
|
344 |
new_table[refcount_table_index] = new_block; |
345 |
|
346 |
int i;
|
347 |
for (i = 0; i < blocks_clusters; i++) { |
348 |
new_table[blocks_used + i] = meta_offset + (i * s->cluster_size); |
349 |
} |
350 |
|
351 |
/* Fill the refcount blocks */
|
352 |
uint64_t table_clusters = size_to_clusters(s, table_size * sizeof(uint64_t));
|
353 |
int block = 0; |
354 |
for (i = 0; i < table_clusters + blocks_clusters; i++) { |
355 |
new_blocks[block++] = cpu_to_be16(1);
|
356 |
} |
357 |
|
358 |
/* Write refcount blocks to disk */
|
359 |
BLKDBG_EVENT(bs->file, BLKDBG_REFBLOCK_ALLOC_WRITE_BLOCKS); |
360 |
ret = bdrv_pwrite_sync(bs->file, meta_offset, new_blocks, |
361 |
blocks_clusters * s->cluster_size); |
362 |
g_free(new_blocks); |
363 |
if (ret < 0) { |
364 |
goto fail_table;
|
365 |
} |
366 |
|
367 |
/* Write refcount table to disk */
|
368 |
for(i = 0; i < table_size; i++) { |
369 |
cpu_to_be64s(&new_table[i]); |
370 |
} |
371 |
|
372 |
BLKDBG_EVENT(bs->file, BLKDBG_REFBLOCK_ALLOC_WRITE_TABLE); |
373 |
ret = bdrv_pwrite_sync(bs->file, table_offset, new_table, |
374 |
table_size * sizeof(uint64_t));
|
375 |
if (ret < 0) { |
376 |
goto fail_table;
|
377 |
} |
378 |
|
379 |
for(i = 0; i < table_size; i++) { |
380 |
be64_to_cpus(&new_table[i]); |
381 |
} |
382 |
|
383 |
/* Hook up the new refcount table in the qcow2 header */
|
384 |
uint8_t data[12];
|
385 |
cpu_to_be64w((uint64_t*)data, table_offset); |
386 |
cpu_to_be32w((uint32_t*)(data + 8), table_clusters);
|
387 |
BLKDBG_EVENT(bs->file, BLKDBG_REFBLOCK_ALLOC_SWITCH_TABLE); |
388 |
ret = bdrv_pwrite_sync(bs->file, offsetof(QCowHeader, refcount_table_offset), |
389 |
data, sizeof(data));
|
390 |
if (ret < 0) { |
391 |
goto fail_table;
|
392 |
} |
393 |
|
394 |
/* And switch it in memory */
|
395 |
uint64_t old_table_offset = s->refcount_table_offset; |
396 |
uint64_t old_table_size = s->refcount_table_size; |
397 |
|
398 |
g_free(s->refcount_table); |
399 |
s->refcount_table = new_table; |
400 |
s->refcount_table_size = table_size; |
401 |
s->refcount_table_offset = table_offset; |
402 |
|
403 |
/* Free old table. Remember, we must not change free_cluster_index */
|
404 |
uint64_t old_free_cluster_index = s->free_cluster_index; |
405 |
qcow2_free_clusters(bs, old_table_offset, old_table_size * sizeof(uint64_t),
|
406 |
QCOW2_DISCARD_OTHER); |
407 |
s->free_cluster_index = old_free_cluster_index; |
408 |
|
409 |
ret = load_refcount_block(bs, new_block, (void**) refcount_block);
|
410 |
if (ret < 0) { |
411 |
return ret;
|
412 |
} |
413 |
|
414 |
return 0; |
415 |
|
416 |
fail_table:
|
417 |
g_free(new_table); |
418 |
fail_block:
|
419 |
if (*refcount_block != NULL) { |
420 |
qcow2_cache_put(bs, s->refcount_block_cache, (void**) refcount_block);
|
421 |
} |
422 |
return ret;
|
423 |
} |
424 |
|
425 |
void qcow2_process_discards(BlockDriverState *bs, int ret) |
426 |
{ |
427 |
BDRVQcowState *s = bs->opaque; |
428 |
Qcow2DiscardRegion *d, *next; |
429 |
|
430 |
QTAILQ_FOREACH_SAFE(d, &s->discards, next, next) { |
431 |
QTAILQ_REMOVE(&s->discards, d, next); |
432 |
|
433 |
/* Discard is optional, ignore the return value */
|
434 |
if (ret >= 0) { |
435 |
bdrv_discard(bs->file, |
436 |
d->offset >> BDRV_SECTOR_BITS, |
437 |
d->bytes >> BDRV_SECTOR_BITS); |
438 |
} |
439 |
|
440 |
g_free(d); |
441 |
} |
442 |
} |
443 |
|
444 |
static void update_refcount_discard(BlockDriverState *bs, |
445 |
uint64_t offset, uint64_t length) |
446 |
{ |
447 |
BDRVQcowState *s = bs->opaque; |
448 |
Qcow2DiscardRegion *d, *p, *next; |
449 |
|
450 |
QTAILQ_FOREACH(d, &s->discards, next) { |
451 |
uint64_t new_start = MIN(offset, d->offset); |
452 |
uint64_t new_end = MAX(offset + length, d->offset + d->bytes); |
453 |
|
454 |
if (new_end - new_start <= length + d->bytes) {
|
455 |
/* There can't be any overlap, areas ending up here have no
|
456 |
* references any more and therefore shouldn't get freed another
|
457 |
* time. */
|
458 |
assert(d->bytes + length == new_end - new_start); |
459 |
d->offset = new_start; |
460 |
d->bytes = new_end - new_start; |
461 |
goto found;
|
462 |
} |
463 |
} |
464 |
|
465 |
d = g_malloc(sizeof(*d));
|
466 |
*d = (Qcow2DiscardRegion) { |
467 |
.bs = bs, |
468 |
.offset = offset, |
469 |
.bytes = length, |
470 |
}; |
471 |
QTAILQ_INSERT_TAIL(&s->discards, d, next); |
472 |
|
473 |
found:
|
474 |
/* Merge discard requests if they are adjacent now */
|
475 |
QTAILQ_FOREACH_SAFE(p, &s->discards, next, next) { |
476 |
if (p == d
|
477 |
|| p->offset > d->offset + d->bytes |
478 |
|| d->offset > p->offset + p->bytes) |
479 |
{ |
480 |
continue;
|
481 |
} |
482 |
|
483 |
/* Still no overlap possible */
|
484 |
assert(p->offset == d->offset + d->bytes |
485 |
|| d->offset == p->offset + p->bytes); |
486 |
|
487 |
QTAILQ_REMOVE(&s->discards, p, next); |
488 |
d->offset = MIN(d->offset, p->offset); |
489 |
d->bytes += p->bytes; |
490 |
} |
491 |
} |
492 |
|
493 |
/* XXX: cache several refcount block clusters ? */
|
494 |
static int QEMU_WARN_UNUSED_RESULT update_refcount(BlockDriverState *bs, |
495 |
int64_t offset, int64_t length, int addend, enum qcow2_discard_type type) |
496 |
{ |
497 |
BDRVQcowState *s = bs->opaque; |
498 |
int64_t start, last, cluster_offset; |
499 |
uint16_t *refcount_block = NULL;
|
500 |
int64_t old_table_index = -1;
|
501 |
int ret;
|
502 |
|
503 |
#ifdef DEBUG_ALLOC2
|
504 |
fprintf(stderr, "update_refcount: offset=%" PRId64 " size=%" PRId64 " addend=%d\n", |
505 |
offset, length, addend); |
506 |
#endif
|
507 |
if (length < 0) { |
508 |
return -EINVAL;
|
509 |
} else if (length == 0) { |
510 |
return 0; |
511 |
} |
512 |
|
513 |
if (addend < 0) { |
514 |
qcow2_cache_set_dependency(bs, s->refcount_block_cache, |
515 |
s->l2_table_cache); |
516 |
} |
517 |
|
518 |
start = offset & ~(s->cluster_size - 1);
|
519 |
last = (offset + length - 1) & ~(s->cluster_size - 1); |
520 |
for(cluster_offset = start; cluster_offset <= last;
|
521 |
cluster_offset += s->cluster_size) |
522 |
{ |
523 |
int block_index, refcount;
|
524 |
int64_t cluster_index = cluster_offset >> s->cluster_bits; |
525 |
int64_t table_index = |
526 |
cluster_index >> (s->cluster_bits - REFCOUNT_SHIFT); |
527 |
|
528 |
/* Load the refcount block and allocate it if needed */
|
529 |
if (table_index != old_table_index) {
|
530 |
if (refcount_block) {
|
531 |
ret = qcow2_cache_put(bs, s->refcount_block_cache, |
532 |
(void**) &refcount_block);
|
533 |
if (ret < 0) { |
534 |
goto fail;
|
535 |
} |
536 |
} |
537 |
|
538 |
ret = alloc_refcount_block(bs, cluster_index, &refcount_block); |
539 |
if (ret < 0) { |
540 |
goto fail;
|
541 |
} |
542 |
} |
543 |
old_table_index = table_index; |
544 |
|
545 |
qcow2_cache_entry_mark_dirty(s->refcount_block_cache, refcount_block); |
546 |
|
547 |
/* we can update the count and save it */
|
548 |
block_index = cluster_index & |
549 |
((1 << (s->cluster_bits - REFCOUNT_SHIFT)) - 1); |
550 |
|
551 |
refcount = be16_to_cpu(refcount_block[block_index]); |
552 |
refcount += addend; |
553 |
if (refcount < 0 || refcount > 0xffff) { |
554 |
ret = -EINVAL; |
555 |
goto fail;
|
556 |
} |
557 |
if (refcount == 0 && cluster_index < s->free_cluster_index) { |
558 |
s->free_cluster_index = cluster_index; |
559 |
} |
560 |
refcount_block[block_index] = cpu_to_be16(refcount); |
561 |
|
562 |
if (refcount == 0 && s->discard_passthrough[type]) { |
563 |
update_refcount_discard(bs, cluster_offset, s->cluster_size); |
564 |
} |
565 |
} |
566 |
|
567 |
ret = 0;
|
568 |
fail:
|
569 |
if (!s->cache_discards) {
|
570 |
qcow2_process_discards(bs, ret); |
571 |
} |
572 |
|
573 |
/* Write last changed block to disk */
|
574 |
if (refcount_block) {
|
575 |
int wret;
|
576 |
wret = qcow2_cache_put(bs, s->refcount_block_cache, |
577 |
(void**) &refcount_block);
|
578 |
if (wret < 0) { |
579 |
return ret < 0 ? ret : wret; |
580 |
} |
581 |
} |
582 |
|
583 |
/*
|
584 |
* Try do undo any updates if an error is returned (This may succeed in
|
585 |
* some cases like ENOSPC for allocating a new refcount block)
|
586 |
*/
|
587 |
if (ret < 0) { |
588 |
int dummy;
|
589 |
dummy = update_refcount(bs, offset, cluster_offset - offset, -addend, |
590 |
QCOW2_DISCARD_NEVER); |
591 |
(void)dummy;
|
592 |
} |
593 |
|
594 |
return ret;
|
595 |
} |
596 |
|
597 |
/*
|
598 |
* Increases or decreases the refcount of a given cluster by one.
|
599 |
* addend must be 1 or -1.
|
600 |
*
|
601 |
* If the return value is non-negative, it is the new refcount of the cluster.
|
602 |
* If it is negative, it is -errno and indicates an error.
|
603 |
*/
|
604 |
static int update_cluster_refcount(BlockDriverState *bs, |
605 |
int64_t cluster_index, |
606 |
int addend,
|
607 |
enum qcow2_discard_type type)
|
608 |
{ |
609 |
BDRVQcowState *s = bs->opaque; |
610 |
int ret;
|
611 |
|
612 |
ret = update_refcount(bs, cluster_index << s->cluster_bits, 1, addend,
|
613 |
type); |
614 |
if (ret < 0) { |
615 |
return ret;
|
616 |
} |
617 |
|
618 |
return get_refcount(bs, cluster_index);
|
619 |
} |
620 |
|
621 |
|
622 |
|
623 |
/*********************************************************/
|
624 |
/* cluster allocation functions */
|
625 |
|
626 |
|
627 |
|
628 |
/* return < 0 if error */
|
629 |
static int64_t alloc_clusters_noref(BlockDriverState *bs, int64_t size)
|
630 |
{ |
631 |
BDRVQcowState *s = bs->opaque; |
632 |
int i, nb_clusters, refcount;
|
633 |
|
634 |
nb_clusters = size_to_clusters(s, size); |
635 |
retry:
|
636 |
for(i = 0; i < nb_clusters; i++) { |
637 |
int64_t next_cluster_index = s->free_cluster_index++; |
638 |
refcount = get_refcount(bs, next_cluster_index); |
639 |
|
640 |
if (refcount < 0) { |
641 |
return refcount;
|
642 |
} else if (refcount != 0) { |
643 |
goto retry;
|
644 |
} |
645 |
} |
646 |
#ifdef DEBUG_ALLOC2
|
647 |
fprintf(stderr, "alloc_clusters: size=%" PRId64 " -> %" PRId64 "\n", |
648 |
size, |
649 |
(s->free_cluster_index - nb_clusters) << s->cluster_bits); |
650 |
#endif
|
651 |
return (s->free_cluster_index - nb_clusters) << s->cluster_bits;
|
652 |
} |
653 |
|
654 |
int64_t qcow2_alloc_clusters(BlockDriverState *bs, int64_t size) |
655 |
{ |
656 |
int64_t offset; |
657 |
int ret;
|
658 |
|
659 |
BLKDBG_EVENT(bs->file, BLKDBG_CLUSTER_ALLOC); |
660 |
offset = alloc_clusters_noref(bs, size); |
661 |
if (offset < 0) { |
662 |
return offset;
|
663 |
} |
664 |
|
665 |
ret = update_refcount(bs, offset, size, 1, QCOW2_DISCARD_NEVER);
|
666 |
if (ret < 0) { |
667 |
return ret;
|
668 |
} |
669 |
|
670 |
return offset;
|
671 |
} |
672 |
|
673 |
int qcow2_alloc_clusters_at(BlockDriverState *bs, uint64_t offset,
|
674 |
int nb_clusters)
|
675 |
{ |
676 |
BDRVQcowState *s = bs->opaque; |
677 |
uint64_t cluster_index; |
678 |
uint64_t old_free_cluster_index; |
679 |
int i, refcount, ret;
|
680 |
|
681 |
/* Check how many clusters there are free */
|
682 |
cluster_index = offset >> s->cluster_bits; |
683 |
for(i = 0; i < nb_clusters; i++) { |
684 |
refcount = get_refcount(bs, cluster_index++); |
685 |
|
686 |
if (refcount < 0) { |
687 |
return refcount;
|
688 |
} else if (refcount != 0) { |
689 |
break;
|
690 |
} |
691 |
} |
692 |
|
693 |
/* And then allocate them */
|
694 |
old_free_cluster_index = s->free_cluster_index; |
695 |
s->free_cluster_index = cluster_index + i; |
696 |
|
697 |
ret = update_refcount(bs, offset, i << s->cluster_bits, 1,
|
698 |
QCOW2_DISCARD_NEVER); |
699 |
if (ret < 0) { |
700 |
return ret;
|
701 |
} |
702 |
|
703 |
s->free_cluster_index = old_free_cluster_index; |
704 |
|
705 |
return i;
|
706 |
} |
707 |
|
708 |
/* only used to allocate compressed sectors. We try to allocate
|
709 |
contiguous sectors. size must be <= cluster_size */
|
710 |
int64_t qcow2_alloc_bytes(BlockDriverState *bs, int size)
|
711 |
{ |
712 |
BDRVQcowState *s = bs->opaque; |
713 |
int64_t offset, cluster_offset; |
714 |
int free_in_cluster;
|
715 |
|
716 |
BLKDBG_EVENT(bs->file, BLKDBG_CLUSTER_ALLOC_BYTES); |
717 |
assert(size > 0 && size <= s->cluster_size);
|
718 |
if (s->free_byte_offset == 0) { |
719 |
offset = qcow2_alloc_clusters(bs, s->cluster_size); |
720 |
if (offset < 0) { |
721 |
return offset;
|
722 |
} |
723 |
s->free_byte_offset = offset; |
724 |
} |
725 |
redo:
|
726 |
free_in_cluster = s->cluster_size - |
727 |
(s->free_byte_offset & (s->cluster_size - 1));
|
728 |
if (size <= free_in_cluster) {
|
729 |
/* enough space in current cluster */
|
730 |
offset = s->free_byte_offset; |
731 |
s->free_byte_offset += size; |
732 |
free_in_cluster -= size; |
733 |
if (free_in_cluster == 0) |
734 |
s->free_byte_offset = 0;
|
735 |
if ((offset & (s->cluster_size - 1)) != 0) |
736 |
update_cluster_refcount(bs, offset >> s->cluster_bits, 1,
|
737 |
QCOW2_DISCARD_NEVER); |
738 |
} else {
|
739 |
offset = qcow2_alloc_clusters(bs, s->cluster_size); |
740 |
if (offset < 0) { |
741 |
return offset;
|
742 |
} |
743 |
cluster_offset = s->free_byte_offset & ~(s->cluster_size - 1);
|
744 |
if ((cluster_offset + s->cluster_size) == offset) {
|
745 |
/* we are lucky: contiguous data */
|
746 |
offset = s->free_byte_offset; |
747 |
update_cluster_refcount(bs, offset >> s->cluster_bits, 1,
|
748 |
QCOW2_DISCARD_NEVER); |
749 |
s->free_byte_offset += size; |
750 |
} else {
|
751 |
s->free_byte_offset = offset; |
752 |
goto redo;
|
753 |
} |
754 |
} |
755 |
|
756 |
/* The cluster refcount was incremented, either by qcow2_alloc_clusters()
|
757 |
* or explicitly by update_cluster_refcount(). Refcount blocks must be
|
758 |
* flushed before the caller's L2 table updates.
|
759 |
*/
|
760 |
qcow2_cache_set_dependency(bs, s->l2_table_cache, s->refcount_block_cache); |
761 |
return offset;
|
762 |
} |
763 |
|
764 |
void qcow2_free_clusters(BlockDriverState *bs,
|
765 |
int64_t offset, int64_t size, |
766 |
enum qcow2_discard_type type)
|
767 |
{ |
768 |
int ret;
|
769 |
|
770 |
BLKDBG_EVENT(bs->file, BLKDBG_CLUSTER_FREE); |
771 |
ret = update_refcount(bs, offset, size, -1, type);
|
772 |
if (ret < 0) { |
773 |
fprintf(stderr, "qcow2_free_clusters failed: %s\n", strerror(-ret));
|
774 |
/* TODO Remember the clusters to free them later and avoid leaking */
|
775 |
} |
776 |
} |
777 |
|
778 |
/*
|
779 |
* Free a cluster using its L2 entry (handles clusters of all types, e.g.
|
780 |
* normal cluster, compressed cluster, etc.)
|
781 |
*/
|
782 |
void qcow2_free_any_clusters(BlockDriverState *bs, uint64_t l2_entry,
|
783 |
int nb_clusters, enum qcow2_discard_type type) |
784 |
{ |
785 |
BDRVQcowState *s = bs->opaque; |
786 |
|
787 |
switch (qcow2_get_cluster_type(l2_entry)) {
|
788 |
case QCOW2_CLUSTER_COMPRESSED:
|
789 |
{ |
790 |
int nb_csectors;
|
791 |
nb_csectors = ((l2_entry >> s->csize_shift) & |
792 |
s->csize_mask) + 1;
|
793 |
qcow2_free_clusters(bs, |
794 |
(l2_entry & s->cluster_offset_mask) & ~511,
|
795 |
nb_csectors * 512, type);
|
796 |
} |
797 |
break;
|
798 |
case QCOW2_CLUSTER_NORMAL:
|
799 |
qcow2_free_clusters(bs, l2_entry & L2E_OFFSET_MASK, |
800 |
nb_clusters << s->cluster_bits, type); |
801 |
break;
|
802 |
case QCOW2_CLUSTER_UNALLOCATED:
|
803 |
case QCOW2_CLUSTER_ZERO:
|
804 |
break;
|
805 |
default:
|
806 |
abort(); |
807 |
} |
808 |
} |
809 |
|
810 |
|
811 |
|
812 |
/*********************************************************/
|
813 |
/* snapshots and image creation */
|
814 |
|
815 |
|
816 |
|
817 |
/* update the refcounts of snapshots and the copied flag */
|
818 |
int qcow2_update_snapshot_refcount(BlockDriverState *bs,
|
819 |
int64_t l1_table_offset, int l1_size, int addend) |
820 |
{ |
821 |
BDRVQcowState *s = bs->opaque; |
822 |
uint64_t *l1_table, *l2_table, l2_offset, offset, l1_size2, l1_allocated; |
823 |
int64_t old_offset, old_l2_offset; |
824 |
int i, j, l1_modified = 0, nb_csectors, refcount; |
825 |
int ret;
|
826 |
|
827 |
l2_table = NULL;
|
828 |
l1_table = NULL;
|
829 |
l1_size2 = l1_size * sizeof(uint64_t);
|
830 |
|
831 |
s->cache_discards = true;
|
832 |
|
833 |
/* WARNING: qcow2_snapshot_goto relies on this function not using the
|
834 |
* l1_table_offset when it is the current s->l1_table_offset! Be careful
|
835 |
* when changing this! */
|
836 |
if (l1_table_offset != s->l1_table_offset) {
|
837 |
l1_table = g_malloc0(align_offset(l1_size2, 512));
|
838 |
l1_allocated = 1;
|
839 |
|
840 |
ret = bdrv_pread(bs->file, l1_table_offset, l1_table, l1_size2); |
841 |
if (ret < 0) { |
842 |
goto fail;
|
843 |
} |
844 |
|
845 |
for(i = 0;i < l1_size; i++) |
846 |
be64_to_cpus(&l1_table[i]); |
847 |
} else {
|
848 |
assert(l1_size == s->l1_size); |
849 |
l1_table = s->l1_table; |
850 |
l1_allocated = 0;
|
851 |
} |
852 |
|
853 |
for(i = 0; i < l1_size; i++) { |
854 |
l2_offset = l1_table[i]; |
855 |
if (l2_offset) {
|
856 |
old_l2_offset = l2_offset; |
857 |
l2_offset &= L1E_OFFSET_MASK; |
858 |
|
859 |
ret = qcow2_cache_get(bs, s->l2_table_cache, l2_offset, |
860 |
(void**) &l2_table);
|
861 |
if (ret < 0) { |
862 |
goto fail;
|
863 |
} |
864 |
|
865 |
for(j = 0; j < s->l2_size; j++) { |
866 |
uint64_t cluster_index; |
867 |
|
868 |
offset = be64_to_cpu(l2_table[j]); |
869 |
old_offset = offset; |
870 |
offset &= ~QCOW_OFLAG_COPIED; |
871 |
|
872 |
switch (qcow2_get_cluster_type(offset)) {
|
873 |
case QCOW2_CLUSTER_COMPRESSED:
|
874 |
nb_csectors = ((offset >> s->csize_shift) & |
875 |
s->csize_mask) + 1;
|
876 |
if (addend != 0) { |
877 |
int ret;
|
878 |
ret = update_refcount(bs, |
879 |
(offset & s->cluster_offset_mask) & ~511,
|
880 |
nb_csectors * 512, addend,
|
881 |
QCOW2_DISCARD_SNAPSHOT); |
882 |
if (ret < 0) { |
883 |
goto fail;
|
884 |
} |
885 |
} |
886 |
/* compressed clusters are never modified */
|
887 |
refcount = 2;
|
888 |
break;
|
889 |
|
890 |
case QCOW2_CLUSTER_NORMAL:
|
891 |
case QCOW2_CLUSTER_ZERO:
|
892 |
cluster_index = (offset & L2E_OFFSET_MASK) >> s->cluster_bits; |
893 |
if (!cluster_index) {
|
894 |
/* unallocated */
|
895 |
refcount = 0;
|
896 |
break;
|
897 |
} |
898 |
if (addend != 0) { |
899 |
refcount = update_cluster_refcount(bs, cluster_index, addend, |
900 |
QCOW2_DISCARD_SNAPSHOT); |
901 |
} else {
|
902 |
refcount = get_refcount(bs, cluster_index); |
903 |
} |
904 |
|
905 |
if (refcount < 0) { |
906 |
ret = refcount; |
907 |
goto fail;
|
908 |
} |
909 |
break;
|
910 |
|
911 |
case QCOW2_CLUSTER_UNALLOCATED:
|
912 |
refcount = 0;
|
913 |
break;
|
914 |
|
915 |
default:
|
916 |
abort(); |
917 |
} |
918 |
|
919 |
if (refcount == 1) { |
920 |
offset |= QCOW_OFLAG_COPIED; |
921 |
} |
922 |
if (offset != old_offset) {
|
923 |
if (addend > 0) { |
924 |
qcow2_cache_set_dependency(bs, s->l2_table_cache, |
925 |
s->refcount_block_cache); |
926 |
} |
927 |
l2_table[j] = cpu_to_be64(offset); |
928 |
qcow2_cache_entry_mark_dirty(s->l2_table_cache, l2_table); |
929 |
} |
930 |
} |
931 |
|
932 |
ret = qcow2_cache_put(bs, s->l2_table_cache, (void**) &l2_table);
|
933 |
if (ret < 0) { |
934 |
goto fail;
|
935 |
} |
936 |
|
937 |
|
938 |
if (addend != 0) { |
939 |
refcount = update_cluster_refcount(bs, l2_offset >> s->cluster_bits, addend, |
940 |
QCOW2_DISCARD_SNAPSHOT); |
941 |
} else {
|
942 |
refcount = get_refcount(bs, l2_offset >> s->cluster_bits); |
943 |
} |
944 |
if (refcount < 0) { |
945 |
ret = refcount; |
946 |
goto fail;
|
947 |
} else if (refcount == 1) { |
948 |
l2_offset |= QCOW_OFLAG_COPIED; |
949 |
} |
950 |
if (l2_offset != old_l2_offset) {
|
951 |
l1_table[i] = l2_offset; |
952 |
l1_modified = 1;
|
953 |
} |
954 |
} |
955 |
} |
956 |
|
957 |
ret = bdrv_flush(bs); |
958 |
fail:
|
959 |
if (l2_table) {
|
960 |
qcow2_cache_put(bs, s->l2_table_cache, (void**) &l2_table);
|
961 |
} |
962 |
|
963 |
s->cache_discards = false;
|
964 |
qcow2_process_discards(bs, ret); |
965 |
|
966 |
/* Update L1 only if it isn't deleted anyway (addend = -1) */
|
967 |
if (ret == 0 && addend >= 0 && l1_modified) { |
968 |
for (i = 0; i < l1_size; i++) { |
969 |
cpu_to_be64s(&l1_table[i]); |
970 |
} |
971 |
|
972 |
ret = bdrv_pwrite_sync(bs->file, l1_table_offset, l1_table, l1_size2); |
973 |
|
974 |
for (i = 0; i < l1_size; i++) { |
975 |
be64_to_cpus(&l1_table[i]); |
976 |
} |
977 |
} |
978 |
if (l1_allocated)
|
979 |
g_free(l1_table); |
980 |
return ret;
|
981 |
} |
982 |
|
983 |
|
984 |
|
985 |
|
986 |
/*********************************************************/
|
987 |
/* refcount checking functions */
|
988 |
|
989 |
|
990 |
|
991 |
/*
|
992 |
* Increases the refcount for a range of clusters in a given refcount table.
|
993 |
* This is used to construct a temporary refcount table out of L1 and L2 tables
|
994 |
* which can be compared the the refcount table saved in the image.
|
995 |
*
|
996 |
* Modifies the number of errors in res.
|
997 |
*/
|
998 |
static void inc_refcounts(BlockDriverState *bs, |
999 |
BdrvCheckResult *res, |
1000 |
uint16_t *refcount_table, |
1001 |
int refcount_table_size,
|
1002 |
int64_t offset, int64_t size) |
1003 |
{ |
1004 |
BDRVQcowState *s = bs->opaque; |
1005 |
int64_t start, last, cluster_offset; |
1006 |
int k;
|
1007 |
|
1008 |
if (size <= 0) |
1009 |
return;
|
1010 |
|
1011 |
start = offset & ~(s->cluster_size - 1);
|
1012 |
last = (offset + size - 1) & ~(s->cluster_size - 1); |
1013 |
for(cluster_offset = start; cluster_offset <= last;
|
1014 |
cluster_offset += s->cluster_size) { |
1015 |
k = cluster_offset >> s->cluster_bits; |
1016 |
if (k < 0) { |
1017 |
fprintf(stderr, "ERROR: invalid cluster offset=0x%" PRIx64 "\n", |
1018 |
cluster_offset); |
1019 |
res->corruptions++; |
1020 |
} else if (k >= refcount_table_size) { |
1021 |
fprintf(stderr, "Warning: cluster offset=0x%" PRIx64 " is after " |
1022 |
"the end of the image file, can't properly check refcounts.\n",
|
1023 |
cluster_offset); |
1024 |
res->check_errors++; |
1025 |
} else {
|
1026 |
if (++refcount_table[k] == 0) { |
1027 |
fprintf(stderr, "ERROR: overflow cluster offset=0x%" PRIx64
|
1028 |
"\n", cluster_offset);
|
1029 |
res->corruptions++; |
1030 |
} |
1031 |
} |
1032 |
} |
1033 |
} |
1034 |
|
1035 |
/* Flags for check_refcounts_l1() and check_refcounts_l2() */
|
1036 |
enum {
|
1037 |
CHECK_OFLAG_COPIED = 0x1, /* check QCOW_OFLAG_COPIED matches refcount */ |
1038 |
CHECK_FRAG_INFO = 0x2, /* update BlockFragInfo counters */ |
1039 |
}; |
1040 |
|
1041 |
/*
|
1042 |
* Increases the refcount in the given refcount table for the all clusters
|
1043 |
* referenced in the L2 table. While doing so, performs some checks on L2
|
1044 |
* entries.
|
1045 |
*
|
1046 |
* Returns the number of errors found by the checks or -errno if an internal
|
1047 |
* error occurred.
|
1048 |
*/
|
1049 |
static int check_refcounts_l2(BlockDriverState *bs, BdrvCheckResult *res, |
1050 |
uint16_t *refcount_table, int refcount_table_size, int64_t l2_offset,
|
1051 |
int flags)
|
1052 |
{ |
1053 |
BDRVQcowState *s = bs->opaque; |
1054 |
uint64_t *l2_table, l2_entry; |
1055 |
uint64_t next_contiguous_offset = 0;
|
1056 |
int i, l2_size, nb_csectors;
|
1057 |
|
1058 |
/* Read L2 table from disk */
|
1059 |
l2_size = s->l2_size * sizeof(uint64_t);
|
1060 |
l2_table = g_malloc(l2_size); |
1061 |
|
1062 |
if (bdrv_pread(bs->file, l2_offset, l2_table, l2_size) != l2_size)
|
1063 |
goto fail;
|
1064 |
|
1065 |
/* Do the actual checks */
|
1066 |
for(i = 0; i < s->l2_size; i++) { |
1067 |
l2_entry = be64_to_cpu(l2_table[i]); |
1068 |
|
1069 |
switch (qcow2_get_cluster_type(l2_entry)) {
|
1070 |
case QCOW2_CLUSTER_COMPRESSED:
|
1071 |
/* Compressed clusters don't have QCOW_OFLAG_COPIED */
|
1072 |
if (l2_entry & QCOW_OFLAG_COPIED) {
|
1073 |
fprintf(stderr, "ERROR: cluster %" PRId64 ": " |
1074 |
"copied flag must never be set for compressed "
|
1075 |
"clusters\n", l2_entry >> s->cluster_bits);
|
1076 |
l2_entry &= ~QCOW_OFLAG_COPIED; |
1077 |
res->corruptions++; |
1078 |
} |
1079 |
|
1080 |
/* Mark cluster as used */
|
1081 |
nb_csectors = ((l2_entry >> s->csize_shift) & |
1082 |
s->csize_mask) + 1;
|
1083 |
l2_entry &= s->cluster_offset_mask; |
1084 |
inc_refcounts(bs, res, refcount_table, refcount_table_size, |
1085 |
l2_entry & ~511, nb_csectors * 512); |
1086 |
|
1087 |
if (flags & CHECK_FRAG_INFO) {
|
1088 |
res->bfi.allocated_clusters++; |
1089 |
res->bfi.compressed_clusters++; |
1090 |
|
1091 |
/* Compressed clusters are fragmented by nature. Since they
|
1092 |
* take up sub-sector space but we only have sector granularity
|
1093 |
* I/O we need to re-read the same sectors even for adjacent
|
1094 |
* compressed clusters.
|
1095 |
*/
|
1096 |
res->bfi.fragmented_clusters++; |
1097 |
} |
1098 |
break;
|
1099 |
|
1100 |
case QCOW2_CLUSTER_ZERO:
|
1101 |
if ((l2_entry & L2E_OFFSET_MASK) == 0) { |
1102 |
break;
|
1103 |
} |
1104 |
/* fall through */
|
1105 |
|
1106 |
case QCOW2_CLUSTER_NORMAL:
|
1107 |
{ |
1108 |
uint64_t offset = l2_entry & L2E_OFFSET_MASK; |
1109 |
|
1110 |
if (flags & CHECK_FRAG_INFO) {
|
1111 |
res->bfi.allocated_clusters++; |
1112 |
if (next_contiguous_offset &&
|
1113 |
offset != next_contiguous_offset) { |
1114 |
res->bfi.fragmented_clusters++; |
1115 |
} |
1116 |
next_contiguous_offset = offset + s->cluster_size; |
1117 |
} |
1118 |
|
1119 |
/* Mark cluster as used */
|
1120 |
inc_refcounts(bs, res, refcount_table,refcount_table_size, |
1121 |
offset, s->cluster_size); |
1122 |
|
1123 |
/* Correct offsets are cluster aligned */
|
1124 |
if (offset & (s->cluster_size - 1)) { |
1125 |
fprintf(stderr, "ERROR offset=%" PRIx64 ": Cluster is not " |
1126 |
"properly aligned; L2 entry corrupted.\n", offset);
|
1127 |
res->corruptions++; |
1128 |
} |
1129 |
break;
|
1130 |
} |
1131 |
|
1132 |
case QCOW2_CLUSTER_UNALLOCATED:
|
1133 |
break;
|
1134 |
|
1135 |
default:
|
1136 |
abort(); |
1137 |
} |
1138 |
} |
1139 |
|
1140 |
g_free(l2_table); |
1141 |
return 0; |
1142 |
|
1143 |
fail:
|
1144 |
fprintf(stderr, "ERROR: I/O error in check_refcounts_l2\n");
|
1145 |
g_free(l2_table); |
1146 |
return -EIO;
|
1147 |
} |
1148 |
|
1149 |
/*
|
1150 |
* Increases the refcount for the L1 table, its L2 tables and all referenced
|
1151 |
* clusters in the given refcount table. While doing so, performs some checks
|
1152 |
* on L1 and L2 entries.
|
1153 |
*
|
1154 |
* Returns the number of errors found by the checks or -errno if an internal
|
1155 |
* error occurred.
|
1156 |
*/
|
1157 |
static int check_refcounts_l1(BlockDriverState *bs, |
1158 |
BdrvCheckResult *res, |
1159 |
uint16_t *refcount_table, |
1160 |
int refcount_table_size,
|
1161 |
int64_t l1_table_offset, int l1_size,
|
1162 |
int flags)
|
1163 |
{ |
1164 |
BDRVQcowState *s = bs->opaque; |
1165 |
uint64_t *l1_table, l2_offset, l1_size2; |
1166 |
int i, ret;
|
1167 |
|
1168 |
l1_size2 = l1_size * sizeof(uint64_t);
|
1169 |
|
1170 |
/* Mark L1 table as used */
|
1171 |
inc_refcounts(bs, res, refcount_table, refcount_table_size, |
1172 |
l1_table_offset, l1_size2); |
1173 |
|
1174 |
/* Read L1 table entries from disk */
|
1175 |
if (l1_size2 == 0) { |
1176 |
l1_table = NULL;
|
1177 |
} else {
|
1178 |
l1_table = g_malloc(l1_size2); |
1179 |
if (bdrv_pread(bs->file, l1_table_offset,
|
1180 |
l1_table, l1_size2) != l1_size2) |
1181 |
goto fail;
|
1182 |
for(i = 0;i < l1_size; i++) |
1183 |
be64_to_cpus(&l1_table[i]); |
1184 |
} |
1185 |
|
1186 |
/* Do the actual checks */
|
1187 |
for(i = 0; i < l1_size; i++) { |
1188 |
l2_offset = l1_table[i]; |
1189 |
if (l2_offset) {
|
1190 |
/* Mark L2 table as used */
|
1191 |
l2_offset &= L1E_OFFSET_MASK; |
1192 |
inc_refcounts(bs, res, refcount_table, refcount_table_size, |
1193 |
l2_offset, s->cluster_size); |
1194 |
|
1195 |
/* L2 tables are cluster aligned */
|
1196 |
if (l2_offset & (s->cluster_size - 1)) { |
1197 |
fprintf(stderr, "ERROR l2_offset=%" PRIx64 ": Table is not " |
1198 |
"cluster aligned; L1 entry corrupted\n", l2_offset);
|
1199 |
res->corruptions++; |
1200 |
} |
1201 |
|
1202 |
/* Process and check L2 entries */
|
1203 |
ret = check_refcounts_l2(bs, res, refcount_table, |
1204 |
refcount_table_size, l2_offset, flags); |
1205 |
if (ret < 0) { |
1206 |
goto fail;
|
1207 |
} |
1208 |
} |
1209 |
} |
1210 |
g_free(l1_table); |
1211 |
return 0; |
1212 |
|
1213 |
fail:
|
1214 |
fprintf(stderr, "ERROR: I/O error in check_refcounts_l1\n");
|
1215 |
res->check_errors++; |
1216 |
g_free(l1_table); |
1217 |
return -EIO;
|
1218 |
} |
1219 |
|
1220 |
/*
|
1221 |
* Checks the OFLAG_COPIED flag for all L1 and L2 entries.
|
1222 |
*
|
1223 |
* This function does not print an error message nor does it increment
|
1224 |
* check_errors if get_refcount fails (this is because such an error will have
|
1225 |
* been already detected and sufficiently signaled by the calling function
|
1226 |
* (qcow2_check_refcounts) by the time this function is called).
|
1227 |
*/
|
1228 |
static int check_oflag_copied(BlockDriverState *bs, BdrvCheckResult *res, |
1229 |
BdrvCheckMode fix) |
1230 |
{ |
1231 |
BDRVQcowState *s = bs->opaque; |
1232 |
uint64_t *l2_table = qemu_blockalign(bs, s->cluster_size); |
1233 |
int ret;
|
1234 |
int refcount;
|
1235 |
int i, j;
|
1236 |
|
1237 |
for (i = 0; i < s->l1_size; i++) { |
1238 |
uint64_t l1_entry = s->l1_table[i]; |
1239 |
uint64_t l2_offset = l1_entry & L1E_OFFSET_MASK; |
1240 |
bool l2_dirty = false; |
1241 |
|
1242 |
if (!l2_offset) {
|
1243 |
continue;
|
1244 |
} |
1245 |
|
1246 |
refcount = get_refcount(bs, l2_offset >> s->cluster_bits); |
1247 |
if (refcount < 0) { |
1248 |
/* don't print message nor increment check_errors */
|
1249 |
continue;
|
1250 |
} |
1251 |
if ((refcount == 1) != ((l1_entry & QCOW_OFLAG_COPIED) != 0)) { |
1252 |
fprintf(stderr, "%s OFLAG_COPIED L2 cluster: l1_index=%d "
|
1253 |
"l1_entry=%" PRIx64 " refcount=%d\n", |
1254 |
fix & BDRV_FIX_ERRORS ? "Repairing" :
|
1255 |
"ERROR",
|
1256 |
i, l1_entry, refcount); |
1257 |
if (fix & BDRV_FIX_ERRORS) {
|
1258 |
s->l1_table[i] = refcount == 1
|
1259 |
? l1_entry | QCOW_OFLAG_COPIED |
1260 |
: l1_entry & ~QCOW_OFLAG_COPIED; |
1261 |
ret = qcow2_write_l1_entry(bs, i); |
1262 |
if (ret < 0) { |
1263 |
res->check_errors++; |
1264 |
goto fail;
|
1265 |
} |
1266 |
res->corruptions_fixed++; |
1267 |
} else {
|
1268 |
res->corruptions++; |
1269 |
} |
1270 |
} |
1271 |
|
1272 |
ret = bdrv_pread(bs->file, l2_offset, l2_table, |
1273 |
s->l2_size * sizeof(uint64_t));
|
1274 |
if (ret < 0) { |
1275 |
fprintf(stderr, "ERROR: Could not read L2 table: %s\n",
|
1276 |
strerror(-ret)); |
1277 |
res->check_errors++; |
1278 |
goto fail;
|
1279 |
} |
1280 |
|
1281 |
for (j = 0; j < s->l2_size; j++) { |
1282 |
uint64_t l2_entry = be64_to_cpu(l2_table[j]); |
1283 |
uint64_t data_offset = l2_entry & L2E_OFFSET_MASK; |
1284 |
int cluster_type = qcow2_get_cluster_type(l2_entry);
|
1285 |
|
1286 |
if ((cluster_type == QCOW2_CLUSTER_NORMAL) ||
|
1287 |
((cluster_type == QCOW2_CLUSTER_ZERO) && (data_offset != 0))) {
|
1288 |
refcount = get_refcount(bs, data_offset >> s->cluster_bits); |
1289 |
if (refcount < 0) { |
1290 |
/* don't print message nor increment check_errors */
|
1291 |
continue;
|
1292 |
} |
1293 |
if ((refcount == 1) != ((l2_entry & QCOW_OFLAG_COPIED) != 0)) { |
1294 |
fprintf(stderr, "%s OFLAG_COPIED data cluster: "
|
1295 |
"l2_entry=%" PRIx64 " refcount=%d\n", |
1296 |
fix & BDRV_FIX_ERRORS ? "Repairing" :
|
1297 |
"ERROR",
|
1298 |
l2_entry, refcount); |
1299 |
if (fix & BDRV_FIX_ERRORS) {
|
1300 |
l2_table[j] = cpu_to_be64(refcount == 1
|
1301 |
? l2_entry | QCOW_OFLAG_COPIED |
1302 |
: l2_entry & ~QCOW_OFLAG_COPIED); |
1303 |
l2_dirty = true;
|
1304 |
res->corruptions_fixed++; |
1305 |
} else {
|
1306 |
res->corruptions++; |
1307 |
} |
1308 |
} |
1309 |
} |
1310 |
} |
1311 |
|
1312 |
if (l2_dirty) {
|
1313 |
ret = qcow2_pre_write_overlap_check(bs, |
1314 |
QCOW2_OL_DEFAULT & ~QCOW2_OL_ACTIVE_L2, l2_offset, |
1315 |
s->cluster_size); |
1316 |
if (ret < 0) { |
1317 |
fprintf(stderr, "ERROR: Could not write L2 table; metadata "
|
1318 |
"overlap check failed: %s\n", strerror(-ret));
|
1319 |
res->check_errors++; |
1320 |
goto fail;
|
1321 |
} |
1322 |
|
1323 |
ret = bdrv_pwrite(bs->file, l2_offset, l2_table, s->cluster_size); |
1324 |
if (ret < 0) { |
1325 |
fprintf(stderr, "ERROR: Could not write L2 table: %s\n",
|
1326 |
strerror(-ret)); |
1327 |
res->check_errors++; |
1328 |
goto fail;
|
1329 |
} |
1330 |
} |
1331 |
} |
1332 |
|
1333 |
ret = 0;
|
1334 |
|
1335 |
fail:
|
1336 |
qemu_vfree(l2_table); |
1337 |
return ret;
|
1338 |
} |
1339 |
|
1340 |
/*
|
1341 |
* Writes one sector of the refcount table to the disk
|
1342 |
*/
|
1343 |
#define RT_ENTRIES_PER_SECTOR (512 / sizeof(uint64_t)) |
1344 |
static int write_reftable_entry(BlockDriverState *bs, int rt_index) |
1345 |
{ |
1346 |
BDRVQcowState *s = bs->opaque; |
1347 |
uint64_t buf[RT_ENTRIES_PER_SECTOR]; |
1348 |
int rt_start_index;
|
1349 |
int i, ret;
|
1350 |
|
1351 |
rt_start_index = rt_index & ~(RT_ENTRIES_PER_SECTOR - 1);
|
1352 |
for (i = 0; i < RT_ENTRIES_PER_SECTOR; i++) { |
1353 |
buf[i] = cpu_to_be64(s->refcount_table[rt_start_index + i]); |
1354 |
} |
1355 |
|
1356 |
ret = qcow2_pre_write_overlap_check(bs, |
1357 |
QCOW2_OL_DEFAULT & ~QCOW2_OL_REFCOUNT_TABLE, |
1358 |
s->refcount_table_offset + rt_start_index * sizeof(uint64_t),
|
1359 |
sizeof(buf));
|
1360 |
if (ret < 0) { |
1361 |
return ret;
|
1362 |
} |
1363 |
|
1364 |
BLKDBG_EVENT(bs->file, BLKDBG_REFTABLE_UPDATE); |
1365 |
ret = bdrv_pwrite_sync(bs->file, s->refcount_table_offset + |
1366 |
rt_start_index * sizeof(uint64_t), buf, sizeof(buf)); |
1367 |
if (ret < 0) { |
1368 |
return ret;
|
1369 |
} |
1370 |
|
1371 |
return 0; |
1372 |
} |
1373 |
|
1374 |
/*
|
1375 |
* Allocates a new cluster for the given refcount block (represented by its
|
1376 |
* offset in the image file) and copies the current content there. This function
|
1377 |
* does _not_ decrement the reference count for the currently occupied cluster.
|
1378 |
*
|
1379 |
* This function prints an informative message to stderr on error (and returns
|
1380 |
* -errno); on success, 0 is returned.
|
1381 |
*/
|
1382 |
static int64_t realloc_refcount_block(BlockDriverState *bs, int reftable_index, |
1383 |
uint64_t offset) |
1384 |
{ |
1385 |
BDRVQcowState *s = bs->opaque; |
1386 |
int64_t new_offset = 0;
|
1387 |
void *refcount_block = NULL; |
1388 |
int ret;
|
1389 |
|
1390 |
/* allocate new refcount block */
|
1391 |
new_offset = qcow2_alloc_clusters(bs, s->cluster_size); |
1392 |
if (new_offset < 0) { |
1393 |
fprintf(stderr, "Could not allocate new cluster: %s\n",
|
1394 |
strerror(-new_offset)); |
1395 |
ret = new_offset; |
1396 |
goto fail;
|
1397 |
} |
1398 |
|
1399 |
/* fetch current refcount block content */
|
1400 |
ret = qcow2_cache_get(bs, s->refcount_block_cache, offset, &refcount_block); |
1401 |
if (ret < 0) { |
1402 |
fprintf(stderr, "Could not fetch refcount block: %s\n", strerror(-ret));
|
1403 |
goto fail;
|
1404 |
} |
1405 |
|
1406 |
/* new block has not yet been entered into refcount table, therefore it is
|
1407 |
* no refcount block yet (regarding this check) */
|
1408 |
ret = qcow2_pre_write_overlap_check(bs, QCOW2_OL_DEFAULT, new_offset, |
1409 |
s->cluster_size); |
1410 |
if (ret < 0) { |
1411 |
fprintf(stderr, "Could not write refcount block; metadata overlap "
|
1412 |
"check failed: %s\n", strerror(-ret));
|
1413 |
/* the image will be marked corrupt, so don't even attempt on freeing
|
1414 |
* the cluster */
|
1415 |
new_offset = 0;
|
1416 |
goto fail;
|
1417 |
} |
1418 |
|
1419 |
/* write to new block */
|
1420 |
ret = bdrv_write(bs->file, new_offset / BDRV_SECTOR_SIZE, refcount_block, |
1421 |
s->cluster_sectors); |
1422 |
if (ret < 0) { |
1423 |
fprintf(stderr, "Could not write refcount block: %s\n", strerror(-ret));
|
1424 |
goto fail;
|
1425 |
} |
1426 |
|
1427 |
/* update refcount table */
|
1428 |
assert(!(new_offset & (s->cluster_size - 1)));
|
1429 |
s->refcount_table[reftable_index] = new_offset; |
1430 |
ret = write_reftable_entry(bs, reftable_index); |
1431 |
if (ret < 0) { |
1432 |
fprintf(stderr, "Could not update refcount table: %s\n",
|
1433 |
strerror(-ret)); |
1434 |
goto fail;
|
1435 |
} |
1436 |
|
1437 |
fail:
|
1438 |
if (new_offset && (ret < 0)) { |
1439 |
qcow2_free_clusters(bs, new_offset, s->cluster_size, |
1440 |
QCOW2_DISCARD_ALWAYS); |
1441 |
} |
1442 |
if (refcount_block) {
|
1443 |
if (ret < 0) { |
1444 |
qcow2_cache_put(bs, s->refcount_block_cache, &refcount_block); |
1445 |
} else {
|
1446 |
ret = qcow2_cache_put(bs, s->refcount_block_cache, &refcount_block); |
1447 |
} |
1448 |
} |
1449 |
if (ret < 0) { |
1450 |
return ret;
|
1451 |
} |
1452 |
return new_offset;
|
1453 |
} |
1454 |
|
1455 |
/*
|
1456 |
* Checks an image for refcount consistency.
|
1457 |
*
|
1458 |
* Returns 0 if no errors are found, the number of errors in case the image is
|
1459 |
* detected as corrupted, and -errno when an internal error occurred.
|
1460 |
*/
|
1461 |
int qcow2_check_refcounts(BlockDriverState *bs, BdrvCheckResult *res,
|
1462 |
BdrvCheckMode fix) |
1463 |
{ |
1464 |
BDRVQcowState *s = bs->opaque; |
1465 |
int64_t size, i, highest_cluster; |
1466 |
int nb_clusters, refcount1, refcount2;
|
1467 |
QCowSnapshot *sn; |
1468 |
uint16_t *refcount_table; |
1469 |
int ret;
|
1470 |
|
1471 |
size = bdrv_getlength(bs->file); |
1472 |
nb_clusters = size_to_clusters(s, size); |
1473 |
refcount_table = g_malloc0(nb_clusters * sizeof(uint16_t));
|
1474 |
|
1475 |
res->bfi.total_clusters = |
1476 |
size_to_clusters(s, bs->total_sectors * BDRV_SECTOR_SIZE); |
1477 |
|
1478 |
/* header */
|
1479 |
inc_refcounts(bs, res, refcount_table, nb_clusters, |
1480 |
0, s->cluster_size);
|
1481 |
|
1482 |
/* current L1 table */
|
1483 |
ret = check_refcounts_l1(bs, res, refcount_table, nb_clusters, |
1484 |
s->l1_table_offset, s->l1_size, |
1485 |
CHECK_OFLAG_COPIED | CHECK_FRAG_INFO); |
1486 |
if (ret < 0) { |
1487 |
goto fail;
|
1488 |
} |
1489 |
|
1490 |
/* snapshots */
|
1491 |
for(i = 0; i < s->nb_snapshots; i++) { |
1492 |
sn = s->snapshots + i; |
1493 |
ret = check_refcounts_l1(bs, res, refcount_table, nb_clusters, |
1494 |
sn->l1_table_offset, sn->l1_size, 0);
|
1495 |
if (ret < 0) { |
1496 |
goto fail;
|
1497 |
} |
1498 |
} |
1499 |
inc_refcounts(bs, res, refcount_table, nb_clusters, |
1500 |
s->snapshots_offset, s->snapshots_size); |
1501 |
|
1502 |
/* refcount data */
|
1503 |
inc_refcounts(bs, res, refcount_table, nb_clusters, |
1504 |
s->refcount_table_offset, |
1505 |
s->refcount_table_size * sizeof(uint64_t));
|
1506 |
|
1507 |
for(i = 0; i < s->refcount_table_size; i++) { |
1508 |
uint64_t offset, cluster; |
1509 |
offset = s->refcount_table[i]; |
1510 |
cluster = offset >> s->cluster_bits; |
1511 |
|
1512 |
/* Refcount blocks are cluster aligned */
|
1513 |
if (offset & (s->cluster_size - 1)) { |
1514 |
fprintf(stderr, "ERROR refcount block %" PRId64 " is not " |
1515 |
"cluster aligned; refcount table entry corrupted\n", i);
|
1516 |
res->corruptions++; |
1517 |
continue;
|
1518 |
} |
1519 |
|
1520 |
if (cluster >= nb_clusters) {
|
1521 |
fprintf(stderr, "ERROR refcount block %" PRId64
|
1522 |
" is outside image\n", i);
|
1523 |
res->corruptions++; |
1524 |
continue;
|
1525 |
} |
1526 |
|
1527 |
if (offset != 0) { |
1528 |
inc_refcounts(bs, res, refcount_table, nb_clusters, |
1529 |
offset, s->cluster_size); |
1530 |
if (refcount_table[cluster] != 1) { |
1531 |
fprintf(stderr, "%s refcount block %" PRId64
|
1532 |
" refcount=%d\n",
|
1533 |
fix & BDRV_FIX_ERRORS ? "Repairing" :
|
1534 |
"ERROR",
|
1535 |
i, refcount_table[cluster]); |
1536 |
|
1537 |
if (fix & BDRV_FIX_ERRORS) {
|
1538 |
int64_t new_offset; |
1539 |
|
1540 |
new_offset = realloc_refcount_block(bs, i, offset); |
1541 |
if (new_offset < 0) { |
1542 |
res->corruptions++; |
1543 |
continue;
|
1544 |
} |
1545 |
|
1546 |
/* update refcounts */
|
1547 |
if ((new_offset >> s->cluster_bits) >= nb_clusters) {
|
1548 |
/* increase refcount_table size if necessary */
|
1549 |
int old_nb_clusters = nb_clusters;
|
1550 |
nb_clusters = (new_offset >> s->cluster_bits) + 1;
|
1551 |
refcount_table = g_realloc(refcount_table, |
1552 |
nb_clusters * sizeof(uint16_t));
|
1553 |
memset(&refcount_table[old_nb_clusters], 0, (nb_clusters
|
1554 |
- old_nb_clusters) * sizeof(uint16_t));
|
1555 |
} |
1556 |
refcount_table[cluster]--; |
1557 |
inc_refcounts(bs, res, refcount_table, nb_clusters, |
1558 |
new_offset, s->cluster_size); |
1559 |
|
1560 |
res->corruptions_fixed++; |
1561 |
} else {
|
1562 |
res->corruptions++; |
1563 |
} |
1564 |
} |
1565 |
} |
1566 |
} |
1567 |
|
1568 |
/* compare ref counts */
|
1569 |
for (i = 0, highest_cluster = 0; i < nb_clusters; i++) { |
1570 |
refcount1 = get_refcount(bs, i); |
1571 |
if (refcount1 < 0) { |
1572 |
fprintf(stderr, "Can't get refcount for cluster %" PRId64 ": %s\n", |
1573 |
i, strerror(-refcount1)); |
1574 |
res->check_errors++; |
1575 |
continue;
|
1576 |
} |
1577 |
|
1578 |
refcount2 = refcount_table[i]; |
1579 |
|
1580 |
if (refcount1 > 0 || refcount2 > 0) { |
1581 |
highest_cluster = i; |
1582 |
} |
1583 |
|
1584 |
if (refcount1 != refcount2) {
|
1585 |
|
1586 |
/* Check if we're allowed to fix the mismatch */
|
1587 |
int *num_fixed = NULL; |
1588 |
if (refcount1 > refcount2 && (fix & BDRV_FIX_LEAKS)) {
|
1589 |
num_fixed = &res->leaks_fixed; |
1590 |
} else if (refcount1 < refcount2 && (fix & BDRV_FIX_ERRORS)) { |
1591 |
num_fixed = &res->corruptions_fixed; |
1592 |
} |
1593 |
|
1594 |
fprintf(stderr, "%s cluster %" PRId64 " refcount=%d reference=%d\n", |
1595 |
num_fixed != NULL ? "Repairing" : |
1596 |
refcount1 < refcount2 ? "ERROR" :
|
1597 |
"Leaked",
|
1598 |
i, refcount1, refcount2); |
1599 |
|
1600 |
if (num_fixed) {
|
1601 |
ret = update_refcount(bs, i << s->cluster_bits, 1,
|
1602 |
refcount2 - refcount1, |
1603 |
QCOW2_DISCARD_ALWAYS); |
1604 |
if (ret >= 0) { |
1605 |
(*num_fixed)++; |
1606 |
continue;
|
1607 |
} |
1608 |
} |
1609 |
|
1610 |
/* And if we couldn't, print an error */
|
1611 |
if (refcount1 < refcount2) {
|
1612 |
res->corruptions++; |
1613 |
} else {
|
1614 |
res->leaks++; |
1615 |
} |
1616 |
} |
1617 |
} |
1618 |
|
1619 |
/* check OFLAG_COPIED */
|
1620 |
ret = check_oflag_copied(bs, res, fix); |
1621 |
if (ret < 0) { |
1622 |
goto fail;
|
1623 |
} |
1624 |
|
1625 |
res->image_end_offset = (highest_cluster + 1) * s->cluster_size;
|
1626 |
ret = 0;
|
1627 |
|
1628 |
fail:
|
1629 |
g_free(refcount_table); |
1630 |
|
1631 |
return ret;
|
1632 |
} |
1633 |
|
1634 |
#define overlaps_with(ofs, sz) \
|
1635 |
ranges_overlap(offset, size, ofs, sz) |
1636 |
|
1637 |
/*
|
1638 |
* Checks if the given offset into the image file is actually free to use by
|
1639 |
* looking for overlaps with important metadata sections (L1/L2 tables etc.),
|
1640 |
* i.e. a sanity check without relying on the refcount tables.
|
1641 |
*
|
1642 |
* The chk parameter specifies exactly what checks to perform (being a bitmask
|
1643 |
* of QCow2MetadataOverlap values).
|
1644 |
*
|
1645 |
* Returns:
|
1646 |
* - 0 if writing to this offset will not affect the mentioned metadata
|
1647 |
* - a positive QCow2MetadataOverlap value indicating one overlapping section
|
1648 |
* - a negative value (-errno) indicating an error while performing a check,
|
1649 |
* e.g. when bdrv_read failed on QCOW2_OL_INACTIVE_L2
|
1650 |
*/
|
1651 |
int qcow2_check_metadata_overlap(BlockDriverState *bs, int chk, int64_t offset, |
1652 |
int64_t size) |
1653 |
{ |
1654 |
BDRVQcowState *s = bs->opaque; |
1655 |
int i, j;
|
1656 |
|
1657 |
if (!size) {
|
1658 |
return 0; |
1659 |
} |
1660 |
|
1661 |
if (chk & QCOW2_OL_MAIN_HEADER) {
|
1662 |
if (offset < s->cluster_size) {
|
1663 |
return QCOW2_OL_MAIN_HEADER;
|
1664 |
} |
1665 |
} |
1666 |
|
1667 |
/* align range to test to cluster boundaries */
|
1668 |
size = align_offset(offset_into_cluster(s, offset) + size, s->cluster_size); |
1669 |
offset = start_of_cluster(s, offset); |
1670 |
|
1671 |
if ((chk & QCOW2_OL_ACTIVE_L1) && s->l1_size) {
|
1672 |
if (overlaps_with(s->l1_table_offset, s->l1_size * sizeof(uint64_t))) { |
1673 |
return QCOW2_OL_ACTIVE_L1;
|
1674 |
} |
1675 |
} |
1676 |
|
1677 |
if ((chk & QCOW2_OL_REFCOUNT_TABLE) && s->refcount_table_size) {
|
1678 |
if (overlaps_with(s->refcount_table_offset,
|
1679 |
s->refcount_table_size * sizeof(uint64_t))) {
|
1680 |
return QCOW2_OL_REFCOUNT_TABLE;
|
1681 |
} |
1682 |
} |
1683 |
|
1684 |
if ((chk & QCOW2_OL_SNAPSHOT_TABLE) && s->snapshots_size) {
|
1685 |
if (overlaps_with(s->snapshots_offset, s->snapshots_size)) {
|
1686 |
return QCOW2_OL_SNAPSHOT_TABLE;
|
1687 |
} |
1688 |
} |
1689 |
|
1690 |
if ((chk & QCOW2_OL_INACTIVE_L1) && s->snapshots) {
|
1691 |
for (i = 0; i < s->nb_snapshots; i++) { |
1692 |
if (s->snapshots[i].l1_size &&
|
1693 |
overlaps_with(s->snapshots[i].l1_table_offset, |
1694 |
s->snapshots[i].l1_size * sizeof(uint64_t))) {
|
1695 |
return QCOW2_OL_INACTIVE_L1;
|
1696 |
} |
1697 |
} |
1698 |
} |
1699 |
|
1700 |
if ((chk & QCOW2_OL_ACTIVE_L2) && s->l1_table) {
|
1701 |
for (i = 0; i < s->l1_size; i++) { |
1702 |
if ((s->l1_table[i] & L1E_OFFSET_MASK) &&
|
1703 |
overlaps_with(s->l1_table[i] & L1E_OFFSET_MASK, |
1704 |
s->cluster_size)) { |
1705 |
return QCOW2_OL_ACTIVE_L2;
|
1706 |
} |
1707 |
} |
1708 |
} |
1709 |
|
1710 |
if ((chk & QCOW2_OL_REFCOUNT_BLOCK) && s->refcount_table) {
|
1711 |
for (i = 0; i < s->refcount_table_size; i++) { |
1712 |
if ((s->refcount_table[i] & REFT_OFFSET_MASK) &&
|
1713 |
overlaps_with(s->refcount_table[i] & REFT_OFFSET_MASK, |
1714 |
s->cluster_size)) { |
1715 |
return QCOW2_OL_REFCOUNT_BLOCK;
|
1716 |
} |
1717 |
} |
1718 |
} |
1719 |
|
1720 |
if ((chk & QCOW2_OL_INACTIVE_L2) && s->snapshots) {
|
1721 |
for (i = 0; i < s->nb_snapshots; i++) { |
1722 |
uint64_t l1_ofs = s->snapshots[i].l1_table_offset; |
1723 |
uint32_t l1_sz = s->snapshots[i].l1_size; |
1724 |
uint64_t *l1 = g_malloc(l1_sz * sizeof(uint64_t));
|
1725 |
int ret;
|
1726 |
|
1727 |
ret = bdrv_read(bs->file, l1_ofs / BDRV_SECTOR_SIZE, (uint8_t *)l1, |
1728 |
l1_sz * sizeof(uint64_t) / BDRV_SECTOR_SIZE);
|
1729 |
|
1730 |
if (ret < 0) { |
1731 |
g_free(l1); |
1732 |
return ret;
|
1733 |
} |
1734 |
|
1735 |
for (j = 0; j < l1_sz; j++) { |
1736 |
if ((l1[j] & L1E_OFFSET_MASK) &&
|
1737 |
overlaps_with(l1[j] & L1E_OFFSET_MASK, s->cluster_size)) { |
1738 |
g_free(l1); |
1739 |
return QCOW2_OL_INACTIVE_L2;
|
1740 |
} |
1741 |
} |
1742 |
|
1743 |
g_free(l1); |
1744 |
} |
1745 |
} |
1746 |
|
1747 |
return 0; |
1748 |
} |
1749 |
|
1750 |
static const char *metadata_ol_names[] = { |
1751 |
[QCOW2_OL_MAIN_HEADER_BITNR] = "qcow2_header",
|
1752 |
[QCOW2_OL_ACTIVE_L1_BITNR] = "active L1 table",
|
1753 |
[QCOW2_OL_ACTIVE_L2_BITNR] = "active L2 table",
|
1754 |
[QCOW2_OL_REFCOUNT_TABLE_BITNR] = "refcount table",
|
1755 |
[QCOW2_OL_REFCOUNT_BLOCK_BITNR] = "refcount block",
|
1756 |
[QCOW2_OL_SNAPSHOT_TABLE_BITNR] = "snapshot table",
|
1757 |
[QCOW2_OL_INACTIVE_L1_BITNR] = "inactive L1 table",
|
1758 |
[QCOW2_OL_INACTIVE_L2_BITNR] = "inactive L2 table",
|
1759 |
}; |
1760 |
|
1761 |
/*
|
1762 |
* First performs a check for metadata overlaps (through
|
1763 |
* qcow2_check_metadata_overlap); if that fails with a negative value (error
|
1764 |
* while performing a check), that value is returned. If an impending overlap
|
1765 |
* is detected, the BDS will be made unusable, the qcow2 file marked corrupt
|
1766 |
* and -EIO returned.
|
1767 |
*
|
1768 |
* Returns 0 if there were neither overlaps nor errors while checking for
|
1769 |
* overlaps; or a negative value (-errno) on error.
|
1770 |
*/
|
1771 |
int qcow2_pre_write_overlap_check(BlockDriverState *bs, int chk, int64_t offset, |
1772 |
int64_t size) |
1773 |
{ |
1774 |
int ret = qcow2_check_metadata_overlap(bs, chk, offset, size);
|
1775 |
|
1776 |
if (ret < 0) { |
1777 |
return ret;
|
1778 |
} else if (ret > 0) { |
1779 |
int metadata_ol_bitnr = ffs(ret) - 1; |
1780 |
char *message;
|
1781 |
QObject *data; |
1782 |
|
1783 |
assert(metadata_ol_bitnr < QCOW2_OL_MAX_BITNR); |
1784 |
|
1785 |
fprintf(stderr, "qcow2: Preventing invalid write on metadata (overlaps "
|
1786 |
"with %s); image marked as corrupt.\n",
|
1787 |
metadata_ol_names[metadata_ol_bitnr]); |
1788 |
message = g_strdup_printf("Prevented %s overwrite",
|
1789 |
metadata_ol_names[metadata_ol_bitnr]); |
1790 |
data = qobject_from_jsonf("{ 'device': %s, 'msg': %s, 'offset': %"
|
1791 |
PRId64 ", 'size': %" PRId64 " }", bs->device_name, message, |
1792 |
offset, size); |
1793 |
monitor_protocol_event(QEVENT_BLOCK_IMAGE_CORRUPTED, data); |
1794 |
g_free(message); |
1795 |
qobject_decref(data); |
1796 |
|
1797 |
qcow2_mark_corrupt(bs); |
1798 |
bs->drv = NULL; /* make BDS unusable */ |
1799 |
return -EIO;
|
1800 |
} |
1801 |
|
1802 |
return 0; |
1803 |
} |