root / block / qcow2-refcount.c @ 5d757b56
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/*
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|---|---|
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* Block driver for the QCOW version 2 format
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*
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* Copyright (c) 2004-2006 Fabrice Bellard
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
|
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* of this software and associated documentation files (the "Software"), to deal
|
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* in the Software without restriction, including without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
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* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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* THE SOFTWARE.
|
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*/
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#include "qemu-common.h" |
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#include "block_int.h" |
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#include "block/qcow2.h" |
| 28 |
|
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static int64_t alloc_clusters_noref(BlockDriverState *bs, int64_t size);
|
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static int update_refcount(BlockDriverState *bs, |
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int64_t offset, int64_t length, |
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int addend);
|
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|
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|
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static int cache_refcount_updates = 0; |
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|
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static int write_refcount_block(BDRVQcowState *s) |
| 38 |
{
|
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size_t size = s->cluster_size; |
| 40 |
|
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if (s->refcount_block_cache_offset == 0) { |
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return 0; |
| 43 |
} |
| 44 |
|
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if (bdrv_pwrite(s->hd, s->refcount_block_cache_offset,
|
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s->refcount_block_cache, size) != size) |
| 47 |
{
|
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return -EIO;
|
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} |
| 50 |
|
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return 0; |
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} |
| 53 |
|
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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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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); |
| 65 |
if (s->refcount_table_size > 0) { |
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ret = bdrv_pread(s->hd, s->refcount_table_offset, |
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s->refcount_table, refcount_table_size2); |
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if (ret != refcount_table_size2)
|
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goto fail;
|
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for(i = 0; i < s->refcount_table_size; i++) |
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be64_to_cpus(&s->refcount_table[i]); |
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} |
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return 0; |
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fail:
|
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return -ENOMEM;
|
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} |
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|
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void qcow2_refcount_close(BlockDriverState *bs)
|
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{
|
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BDRVQcowState *s = bs->opaque; |
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qemu_free(s->refcount_block_cache); |
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qemu_free(s->refcount_table); |
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} |
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|
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|
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static int load_refcount_block(BlockDriverState *bs, |
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int64_t refcount_block_offset) |
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{
|
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BDRVQcowState *s = bs->opaque; |
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int ret;
|
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|
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if (cache_refcount_updates) {
|
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write_refcount_block(s); |
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} |
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|
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ret = bdrv_pread(s->hd, refcount_block_offset, s->refcount_block_cache, |
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s->cluster_size); |
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if (ret != s->cluster_size)
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return -EIO;
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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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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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|
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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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if (load_refcount_block(bs, refcount_block_offset) < 0) |
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return 1; |
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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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static int grow_refcount_table(BlockDriverState *bs, int min_size) |
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{
|
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BDRVQcowState *s = bs->opaque; |
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int new_table_size, new_table_size2, refcount_table_clusters, i, ret;
|
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uint64_t *new_table; |
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int64_t table_offset; |
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uint8_t data[12];
|
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int old_table_size;
|
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int64_t old_table_offset; |
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|
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if (min_size <= s->refcount_table_size)
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return 0; |
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/* compute new table size */
|
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refcount_table_clusters = s->refcount_table_size >> (s->cluster_bits - 3);
|
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for(;;) {
|
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if (refcount_table_clusters == 0) { |
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refcount_table_clusters = 1;
|
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} else {
|
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refcount_table_clusters = (refcount_table_clusters * 3 + 1) / 2; |
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} |
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new_table_size = refcount_table_clusters << (s->cluster_bits - 3);
|
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if (min_size <= new_table_size)
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break;
|
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} |
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#ifdef DEBUG_ALLOC2
|
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printf("grow_refcount_table from %d to %d\n",
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s->refcount_table_size, |
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new_table_size); |
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#endif
|
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new_table_size2 = new_table_size * sizeof(uint64_t);
|
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new_table = qemu_mallocz(new_table_size2); |
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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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for(i = 0; i < s->refcount_table_size; i++) |
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cpu_to_be64s(&new_table[i]); |
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/* Note: we cannot update the refcount now to avoid recursion */
|
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table_offset = alloc_clusters_noref(bs, new_table_size2); |
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ret = bdrv_pwrite(s->hd, table_offset, new_table, new_table_size2); |
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if (ret != new_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(&new_table[i]); |
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|
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cpu_to_be64w((uint64_t*)data, table_offset); |
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cpu_to_be32w((uint32_t*)(data + 8), refcount_table_clusters);
|
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ret = bdrv_pwrite(s->hd, offsetof(QCowHeader, refcount_table_offset), |
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data, sizeof(data));
|
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if (ret != sizeof(data)) { |
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goto fail;
|
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} |
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|
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qemu_free(s->refcount_table); |
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old_table_offset = s->refcount_table_offset; |
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old_table_size = s->refcount_table_size; |
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s->refcount_table = new_table; |
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s->refcount_table_size = new_table_size; |
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s->refcount_table_offset = table_offset; |
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|
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update_refcount(bs, table_offset, new_table_size2, 1);
|
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qcow2_free_clusters(bs, old_table_offset, old_table_size * sizeof(uint64_t));
|
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return 0; |
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fail:
|
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qemu_free(new_table); |
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return ret < 0 ? ret : -EIO; |
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} |
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|
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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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int64_t offset, refcount_block_offset; |
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unsigned int refcount_table_index; |
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int ret;
|
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uint64_t data64; |
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int cache = cache_refcount_updates;
|
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|
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/* Find L1 index and grow refcount table if needed */
|
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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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ret = grow_refcount_table(bs, refcount_table_index + 1);
|
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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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/* Load or allocate the refcount block */
|
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refcount_block_offset = s->refcount_table[refcount_table_index]; |
| 212 |
if (!refcount_block_offset) {
|
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if (cache_refcount_updates) {
|
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write_refcount_block(s); |
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cache_refcount_updates = 0;
|
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} |
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/* create a new refcount block */
|
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/* Note: we cannot update the refcount now to avoid recursion */
|
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offset = alloc_clusters_noref(bs, s->cluster_size); |
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memset(s->refcount_block_cache, 0, s->cluster_size);
|
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ret = bdrv_pwrite(s->hd, offset, s->refcount_block_cache, s->cluster_size); |
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if (ret != s->cluster_size)
|
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return -EINVAL;
|
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s->refcount_table[refcount_table_index] = offset; |
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data64 = cpu_to_be64(offset); |
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ret = bdrv_pwrite(s->hd, s->refcount_table_offset + |
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refcount_table_index * sizeof(uint64_t),
|
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&data64, sizeof(data64));
|
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if (ret != sizeof(data64)) |
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return -EINVAL;
|
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|
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refcount_block_offset = offset; |
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s->refcount_block_cache_offset = offset; |
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update_refcount(bs, offset, s->cluster_size, 1);
|
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cache_refcount_updates = cache; |
| 236 |
} else {
|
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if (refcount_block_offset != s->refcount_block_cache_offset) {
|
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if (load_refcount_block(bs, refcount_block_offset) < 0) |
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return -EIO;
|
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} |
| 241 |
} |
| 242 |
|
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return refcount_block_offset;
|
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} |
| 245 |
|
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#define REFCOUNTS_PER_SECTOR (512 >> REFCOUNT_SHIFT) |
| 247 |
static int write_refcount_block_entries(BDRVQcowState *s, |
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int64_t refcount_block_offset, int first_index, int last_index) |
| 249 |
{
|
| 250 |
size_t size; |
| 251 |
|
| 252 |
if (cache_refcount_updates) {
|
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return 0; |
| 254 |
} |
| 255 |
|
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first_index &= ~(REFCOUNTS_PER_SECTOR - 1);
|
| 257 |
last_index = (last_index + REFCOUNTS_PER_SECTOR) |
| 258 |
& ~(REFCOUNTS_PER_SECTOR - 1);
|
| 259 |
|
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size = (last_index - first_index) << REFCOUNT_SHIFT; |
| 261 |
if (bdrv_pwrite(s->hd,
|
| 262 |
refcount_block_offset + (first_index << REFCOUNT_SHIFT), |
| 263 |
&s->refcount_block_cache[first_index], size) != size) |
| 264 |
{
|
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return -EIO;
|
| 266 |
} |
| 267 |
|
| 268 |
return 0; |
| 269 |
} |
| 270 |
|
| 271 |
/* XXX: cache several refcount block clusters ? */
|
| 272 |
static int QEMU_WARN_UNUSED_RESULT update_refcount(BlockDriverState *bs, |
| 273 |
int64_t offset, int64_t length, int addend)
|
| 274 |
{
|
| 275 |
BDRVQcowState *s = bs->opaque; |
| 276 |
int64_t start, last, cluster_offset; |
| 277 |
int64_t refcount_block_offset = 0;
|
| 278 |
int64_t table_index = -1, old_table_index;
|
| 279 |
int first_index = -1, last_index = -1; |
| 280 |
int ret;
|
| 281 |
|
| 282 |
#ifdef DEBUG_ALLOC2
|
| 283 |
printf("update_refcount: offset=%" PRId64 " size=%" PRId64 " addend=%d\n", |
| 284 |
offset, length, addend); |
| 285 |
#endif
|
| 286 |
if (length < 0) { |
| 287 |
return -EINVAL;
|
| 288 |
} else if (length == 0) { |
| 289 |
return 0; |
| 290 |
} |
| 291 |
|
| 292 |
start = offset & ~(s->cluster_size - 1);
|
| 293 |
last = (offset + length - 1) & ~(s->cluster_size - 1); |
| 294 |
for(cluster_offset = start; cluster_offset <= last;
|
| 295 |
cluster_offset += s->cluster_size) |
| 296 |
{
|
| 297 |
int block_index, refcount;
|
| 298 |
int64_t cluster_index = cluster_offset >> s->cluster_bits; |
| 299 |
int64_t new_block; |
| 300 |
|
| 301 |
/* Only write refcount block to disk when we are done with it */
|
| 302 |
old_table_index = table_index; |
| 303 |
table_index = cluster_index >> (s->cluster_bits - REFCOUNT_SHIFT); |
| 304 |
if ((old_table_index >= 0) && (table_index != old_table_index)) { |
| 305 |
|
| 306 |
if (write_refcount_block_entries(s, refcount_block_offset,
|
| 307 |
first_index, last_index) < 0)
|
| 308 |
{
|
| 309 |
return -EIO;
|
| 310 |
} |
| 311 |
|
| 312 |
first_index = -1;
|
| 313 |
last_index = -1;
|
| 314 |
} |
| 315 |
|
| 316 |
/* Load the refcount block and allocate it if needed */
|
| 317 |
new_block = alloc_refcount_block(bs, cluster_index); |
| 318 |
if (new_block < 0) { |
| 319 |
ret = new_block; |
| 320 |
goto fail;
|
| 321 |
} |
| 322 |
refcount_block_offset = new_block; |
| 323 |
|
| 324 |
/* we can update the count and save it */
|
| 325 |
block_index = cluster_index & |
| 326 |
((1 << (s->cluster_bits - REFCOUNT_SHIFT)) - 1); |
| 327 |
if (first_index == -1 || block_index < first_index) { |
| 328 |
first_index = block_index; |
| 329 |
} |
| 330 |
if (block_index > last_index) {
|
| 331 |
last_index = block_index; |
| 332 |
} |
| 333 |
|
| 334 |
refcount = be16_to_cpu(s->refcount_block_cache[block_index]); |
| 335 |
refcount += addend; |
| 336 |
if (refcount < 0 || refcount > 0xffff) { |
| 337 |
ret = -EINVAL; |
| 338 |
goto fail;
|
| 339 |
} |
| 340 |
if (refcount == 0 && cluster_index < s->free_cluster_index) { |
| 341 |
s->free_cluster_index = cluster_index; |
| 342 |
} |
| 343 |
s->refcount_block_cache[block_index] = cpu_to_be16(refcount); |
| 344 |
} |
| 345 |
|
| 346 |
ret = 0;
|
| 347 |
fail:
|
| 348 |
|
| 349 |
/* Write last changed block to disk */
|
| 350 |
if (refcount_block_offset != 0) { |
| 351 |
if (write_refcount_block_entries(s, refcount_block_offset,
|
| 352 |
first_index, last_index) < 0)
|
| 353 |
{
|
| 354 |
return ret < 0 ? ret : -EIO; |
| 355 |
} |
| 356 |
} |
| 357 |
|
| 358 |
/*
|
| 359 |
* Try do undo any updates if an error is returned (This may succeed in
|
| 360 |
* some cases like ENOSPC for allocating a new refcount block)
|
| 361 |
*/
|
| 362 |
if (ret < 0) { |
| 363 |
int dummy;
|
| 364 |
dummy = update_refcount(bs, offset, cluster_offset - offset, -addend); |
| 365 |
} |
| 366 |
|
| 367 |
return ret;
|
| 368 |
} |
| 369 |
|
| 370 |
/* addend must be 1 or -1 */
|
| 371 |
static int update_cluster_refcount(BlockDriverState *bs, |
| 372 |
int64_t cluster_index, |
| 373 |
int addend)
|
| 374 |
{
|
| 375 |
BDRVQcowState *s = bs->opaque; |
| 376 |
int ret;
|
| 377 |
|
| 378 |
ret = update_refcount(bs, cluster_index << s->cluster_bits, 1, addend);
|
| 379 |
if (ret < 0) { |
| 380 |
return ret;
|
| 381 |
} |
| 382 |
|
| 383 |
return get_refcount(bs, cluster_index);
|
| 384 |
} |
| 385 |
|
| 386 |
|
| 387 |
|
| 388 |
/*********************************************************/
|
| 389 |
/* cluster allocation functions */
|
| 390 |
|
| 391 |
|
| 392 |
|
| 393 |
/* return < 0 if error */
|
| 394 |
static int64_t alloc_clusters_noref(BlockDriverState *bs, int64_t size)
|
| 395 |
{
|
| 396 |
BDRVQcowState *s = bs->opaque; |
| 397 |
int i, nb_clusters;
|
| 398 |
|
| 399 |
nb_clusters = size_to_clusters(s, size); |
| 400 |
retry:
|
| 401 |
for(i = 0; i < nb_clusters; i++) { |
| 402 |
int64_t i = s->free_cluster_index++; |
| 403 |
if (get_refcount(bs, i) != 0) |
| 404 |
goto retry;
|
| 405 |
} |
| 406 |
#ifdef DEBUG_ALLOC2
|
| 407 |
printf("alloc_clusters: size=%" PRId64 " -> %" PRId64 "\n", |
| 408 |
size, |
| 409 |
(s->free_cluster_index - nb_clusters) << s->cluster_bits); |
| 410 |
#endif
|
| 411 |
return (s->free_cluster_index - nb_clusters) << s->cluster_bits;
|
| 412 |
} |
| 413 |
|
| 414 |
int64_t qcow2_alloc_clusters(BlockDriverState *bs, int64_t size) |
| 415 |
{
|
| 416 |
int64_t offset; |
| 417 |
int ret;
|
| 418 |
|
| 419 |
offset = alloc_clusters_noref(bs, size); |
| 420 |
ret = update_refcount(bs, offset, size, 1);
|
| 421 |
if (ret < 0) { |
| 422 |
return ret;
|
| 423 |
} |
| 424 |
return offset;
|
| 425 |
} |
| 426 |
|
| 427 |
/* only used to allocate compressed sectors. We try to allocate
|
| 428 |
contiguous sectors. size must be <= cluster_size */
|
| 429 |
int64_t qcow2_alloc_bytes(BlockDriverState *bs, int size)
|
| 430 |
{
|
| 431 |
BDRVQcowState *s = bs->opaque; |
| 432 |
int64_t offset, cluster_offset; |
| 433 |
int free_in_cluster;
|
| 434 |
|
| 435 |
assert(size > 0 && size <= s->cluster_size);
|
| 436 |
if (s->free_byte_offset == 0) { |
| 437 |
s->free_byte_offset = qcow2_alloc_clusters(bs, s->cluster_size); |
| 438 |
if (s->free_byte_offset < 0) { |
| 439 |
return s->free_byte_offset;
|
| 440 |
} |
| 441 |
} |
| 442 |
redo:
|
| 443 |
free_in_cluster = s->cluster_size - |
| 444 |
(s->free_byte_offset & (s->cluster_size - 1));
|
| 445 |
if (size <= free_in_cluster) {
|
| 446 |
/* enough space in current cluster */
|
| 447 |
offset = s->free_byte_offset; |
| 448 |
s->free_byte_offset += size; |
| 449 |
free_in_cluster -= size; |
| 450 |
if (free_in_cluster == 0) |
| 451 |
s->free_byte_offset = 0;
|
| 452 |
if ((offset & (s->cluster_size - 1)) != 0) |
| 453 |
update_cluster_refcount(bs, offset >> s->cluster_bits, 1);
|
| 454 |
} else {
|
| 455 |
offset = qcow2_alloc_clusters(bs, s->cluster_size); |
| 456 |
if (offset < 0) { |
| 457 |
return offset;
|
| 458 |
} |
| 459 |
cluster_offset = s->free_byte_offset & ~(s->cluster_size - 1);
|
| 460 |
if ((cluster_offset + s->cluster_size) == offset) {
|
| 461 |
/* we are lucky: contiguous data */
|
| 462 |
offset = s->free_byte_offset; |
| 463 |
update_cluster_refcount(bs, offset >> s->cluster_bits, 1);
|
| 464 |
s->free_byte_offset += size; |
| 465 |
} else {
|
| 466 |
s->free_byte_offset = offset; |
| 467 |
goto redo;
|
| 468 |
} |
| 469 |
} |
| 470 |
return offset;
|
| 471 |
} |
| 472 |
|
| 473 |
void qcow2_free_clusters(BlockDriverState *bs,
|
| 474 |
int64_t offset, int64_t size) |
| 475 |
{
|
| 476 |
int ret;
|
| 477 |
|
| 478 |
ret = update_refcount(bs, offset, size, -1);
|
| 479 |
if (ret < 0) { |
| 480 |
fprintf(stderr, "qcow2_free_clusters failed: %s\n", strerror(-ret));
|
| 481 |
abort(); |
| 482 |
} |
| 483 |
} |
| 484 |
|
| 485 |
/*
|
| 486 |
* free_any_clusters
|
| 487 |
*
|
| 488 |
* free clusters according to its type: compressed or not
|
| 489 |
*
|
| 490 |
*/
|
| 491 |
|
| 492 |
void qcow2_free_any_clusters(BlockDriverState *bs,
|
| 493 |
uint64_t cluster_offset, int nb_clusters)
|
| 494 |
{
|
| 495 |
BDRVQcowState *s = bs->opaque; |
| 496 |
|
| 497 |
/* free the cluster */
|
| 498 |
|
| 499 |
if (cluster_offset & QCOW_OFLAG_COMPRESSED) {
|
| 500 |
int nb_csectors;
|
| 501 |
nb_csectors = ((cluster_offset >> s->csize_shift) & |
| 502 |
s->csize_mask) + 1;
|
| 503 |
qcow2_free_clusters(bs, |
| 504 |
(cluster_offset & s->cluster_offset_mask) & ~511,
|
| 505 |
nb_csectors * 512);
|
| 506 |
return;
|
| 507 |
} |
| 508 |
|
| 509 |
qcow2_free_clusters(bs, cluster_offset, nb_clusters << s->cluster_bits); |
| 510 |
|
| 511 |
return;
|
| 512 |
} |
| 513 |
|
| 514 |
|
| 515 |
|
| 516 |
/*********************************************************/
|
| 517 |
/* snapshots and image creation */
|
| 518 |
|
| 519 |
|
| 520 |
|
| 521 |
void qcow2_create_refcount_update(QCowCreateState *s, int64_t offset,
|
| 522 |
int64_t size) |
| 523 |
{
|
| 524 |
int refcount;
|
| 525 |
int64_t start, last, cluster_offset; |
| 526 |
uint16_t *p; |
| 527 |
|
| 528 |
start = offset & ~(s->cluster_size - 1);
|
| 529 |
last = (offset + size - 1) & ~(s->cluster_size - 1); |
| 530 |
for(cluster_offset = start; cluster_offset <= last;
|
| 531 |
cluster_offset += s->cluster_size) {
|
| 532 |
p = &s->refcount_block[cluster_offset >> s->cluster_bits]; |
| 533 |
refcount = be16_to_cpu(*p); |
| 534 |
refcount++; |
| 535 |
*p = cpu_to_be16(refcount); |
| 536 |
} |
| 537 |
} |
| 538 |
|
| 539 |
/* update the refcounts of snapshots and the copied flag */
|
| 540 |
int qcow2_update_snapshot_refcount(BlockDriverState *bs,
|
| 541 |
int64_t l1_table_offset, int l1_size, int addend) |
| 542 |
{
|
| 543 |
BDRVQcowState *s = bs->opaque; |
| 544 |
uint64_t *l1_table, *l2_table, l2_offset, offset, l1_size2, l1_allocated; |
| 545 |
int64_t old_offset, old_l2_offset; |
| 546 |
int l2_size, i, j, l1_modified, l2_modified, nb_csectors, refcount;
|
| 547 |
|
| 548 |
qcow2_l2_cache_reset(bs); |
| 549 |
cache_refcount_updates = 1;
|
| 550 |
|
| 551 |
l2_table = NULL;
|
| 552 |
l1_table = NULL;
|
| 553 |
l1_size2 = l1_size * sizeof(uint64_t);
|
| 554 |
if (l1_table_offset != s->l1_table_offset) {
|
| 555 |
if (l1_size2 != 0) { |
| 556 |
l1_table = qemu_mallocz(align_offset(l1_size2, 512));
|
| 557 |
} else {
|
| 558 |
l1_table = NULL;
|
| 559 |
} |
| 560 |
l1_allocated = 1;
|
| 561 |
if (bdrv_pread(s->hd, l1_table_offset,
|
| 562 |
l1_table, l1_size2) != l1_size2) |
| 563 |
goto fail;
|
| 564 |
for(i = 0;i < l1_size; i++) |
| 565 |
be64_to_cpus(&l1_table[i]); |
| 566 |
} else {
|
| 567 |
assert(l1_size == s->l1_size); |
| 568 |
l1_table = s->l1_table; |
| 569 |
l1_allocated = 0;
|
| 570 |
} |
| 571 |
|
| 572 |
l2_size = s->l2_size * sizeof(uint64_t);
|
| 573 |
l2_table = qemu_malloc(l2_size); |
| 574 |
l1_modified = 0;
|
| 575 |
for(i = 0; i < l1_size; i++) { |
| 576 |
l2_offset = l1_table[i]; |
| 577 |
if (l2_offset) {
|
| 578 |
old_l2_offset = l2_offset; |
| 579 |
l2_offset &= ~QCOW_OFLAG_COPIED; |
| 580 |
l2_modified = 0;
|
| 581 |
if (bdrv_pread(s->hd, l2_offset, l2_table, l2_size) != l2_size)
|
| 582 |
goto fail;
|
| 583 |
for(j = 0; j < s->l2_size; j++) { |
| 584 |
offset = be64_to_cpu(l2_table[j]); |
| 585 |
if (offset != 0) { |
| 586 |
old_offset = offset; |
| 587 |
offset &= ~QCOW_OFLAG_COPIED; |
| 588 |
if (offset & QCOW_OFLAG_COMPRESSED) {
|
| 589 |
nb_csectors = ((offset >> s->csize_shift) & |
| 590 |
s->csize_mask) + 1;
|
| 591 |
if (addend != 0) { |
| 592 |
int ret;
|
| 593 |
ret = update_refcount(bs, |
| 594 |
(offset & s->cluster_offset_mask) & ~511,
|
| 595 |
nb_csectors * 512, addend);
|
| 596 |
if (ret < 0) { |
| 597 |
goto fail;
|
| 598 |
} |
| 599 |
} |
| 600 |
/* compressed clusters are never modified */
|
| 601 |
refcount = 2;
|
| 602 |
} else {
|
| 603 |
if (addend != 0) { |
| 604 |
refcount = update_cluster_refcount(bs, offset >> s->cluster_bits, addend); |
| 605 |
} else {
|
| 606 |
refcount = get_refcount(bs, offset >> s->cluster_bits); |
| 607 |
} |
| 608 |
} |
| 609 |
|
| 610 |
if (refcount == 1) { |
| 611 |
offset |= QCOW_OFLAG_COPIED; |
| 612 |
} |
| 613 |
if (offset != old_offset) {
|
| 614 |
l2_table[j] = cpu_to_be64(offset); |
| 615 |
l2_modified = 1;
|
| 616 |
} |
| 617 |
} |
| 618 |
} |
| 619 |
if (l2_modified) {
|
| 620 |
if (bdrv_pwrite(s->hd,
|
| 621 |
l2_offset, l2_table, l2_size) != l2_size) |
| 622 |
goto fail;
|
| 623 |
} |
| 624 |
|
| 625 |
if (addend != 0) { |
| 626 |
refcount = update_cluster_refcount(bs, l2_offset >> s->cluster_bits, addend); |
| 627 |
} else {
|
| 628 |
refcount = get_refcount(bs, l2_offset >> s->cluster_bits); |
| 629 |
} |
| 630 |
if (refcount == 1) { |
| 631 |
l2_offset |= QCOW_OFLAG_COPIED; |
| 632 |
} |
| 633 |
if (l2_offset != old_l2_offset) {
|
| 634 |
l1_table[i] = l2_offset; |
| 635 |
l1_modified = 1;
|
| 636 |
} |
| 637 |
} |
| 638 |
} |
| 639 |
if (l1_modified) {
|
| 640 |
for(i = 0; i < l1_size; i++) |
| 641 |
cpu_to_be64s(&l1_table[i]); |
| 642 |
if (bdrv_pwrite(s->hd, l1_table_offset, l1_table,
|
| 643 |
l1_size2) != l1_size2) |
| 644 |
goto fail;
|
| 645 |
for(i = 0; i < l1_size; i++) |
| 646 |
be64_to_cpus(&l1_table[i]); |
| 647 |
} |
| 648 |
if (l1_allocated)
|
| 649 |
qemu_free(l1_table); |
| 650 |
qemu_free(l2_table); |
| 651 |
cache_refcount_updates = 0;
|
| 652 |
write_refcount_block(s); |
| 653 |
return 0; |
| 654 |
fail:
|
| 655 |
if (l1_allocated)
|
| 656 |
qemu_free(l1_table); |
| 657 |
qemu_free(l2_table); |
| 658 |
cache_refcount_updates = 0;
|
| 659 |
write_refcount_block(s); |
| 660 |
return -EIO;
|
| 661 |
} |
| 662 |
|
| 663 |
|
| 664 |
|
| 665 |
|
| 666 |
/*********************************************************/
|
| 667 |
/* refcount checking functions */
|
| 668 |
|
| 669 |
|
| 670 |
|
| 671 |
/*
|
| 672 |
* Increases the refcount for a range of clusters in a given refcount table.
|
| 673 |
* This is used to construct a temporary refcount table out of L1 and L2 tables
|
| 674 |
* which can be compared the the refcount table saved in the image.
|
| 675 |
*
|
| 676 |
* Returns the number of errors in the image that were found
|
| 677 |
*/
|
| 678 |
static int inc_refcounts(BlockDriverState *bs, |
| 679 |
uint16_t *refcount_table, |
| 680 |
int refcount_table_size,
|
| 681 |
int64_t offset, int64_t size) |
| 682 |
{
|
| 683 |
BDRVQcowState *s = bs->opaque; |
| 684 |
int64_t start, last, cluster_offset; |
| 685 |
int k;
|
| 686 |
int errors = 0; |
| 687 |
|
| 688 |
if (size <= 0) |
| 689 |
return 0; |
| 690 |
|
| 691 |
start = offset & ~(s->cluster_size - 1);
|
| 692 |
last = (offset + size - 1) & ~(s->cluster_size - 1); |
| 693 |
for(cluster_offset = start; cluster_offset <= last;
|
| 694 |
cluster_offset += s->cluster_size) {
|
| 695 |
k = cluster_offset >> s->cluster_bits; |
| 696 |
if (k < 0 || k >= refcount_table_size) { |
| 697 |
fprintf(stderr, "ERROR: invalid cluster offset=0x%" PRIx64 "\n", |
| 698 |
cluster_offset); |
| 699 |
errors++; |
| 700 |
} else {
|
| 701 |
if (++refcount_table[k] == 0) { |
| 702 |
fprintf(stderr, "ERROR: overflow cluster offset=0x%" PRIx64
|
| 703 |
"\n", cluster_offset);
|
| 704 |
errors++; |
| 705 |
} |
| 706 |
} |
| 707 |
} |
| 708 |
|
| 709 |
return errors;
|
| 710 |
} |
| 711 |
|
| 712 |
/*
|
| 713 |
* Increases the refcount in the given refcount table for the all clusters
|
| 714 |
* referenced in the L2 table. While doing so, performs some checks on L2
|
| 715 |
* entries.
|
| 716 |
*
|
| 717 |
* Returns the number of errors found by the checks or -errno if an internal
|
| 718 |
* error occurred.
|
| 719 |
*/
|
| 720 |
static int check_refcounts_l2(BlockDriverState *bs, |
| 721 |
uint16_t *refcount_table, int refcount_table_size, int64_t l2_offset,
|
| 722 |
int check_copied)
|
| 723 |
{
|
| 724 |
BDRVQcowState *s = bs->opaque; |
| 725 |
uint64_t *l2_table, offset; |
| 726 |
int i, l2_size, nb_csectors, refcount;
|
| 727 |
int errors = 0; |
| 728 |
|
| 729 |
/* Read L2 table from disk */
|
| 730 |
l2_size = s->l2_size * sizeof(uint64_t);
|
| 731 |
l2_table = qemu_malloc(l2_size); |
| 732 |
|
| 733 |
if (bdrv_pread(s->hd, l2_offset, l2_table, l2_size) != l2_size)
|
| 734 |
goto fail;
|
| 735 |
|
| 736 |
/* Do the actual checks */
|
| 737 |
for(i = 0; i < s->l2_size; i++) { |
| 738 |
offset = be64_to_cpu(l2_table[i]); |
| 739 |
if (offset != 0) { |
| 740 |
if (offset & QCOW_OFLAG_COMPRESSED) {
|
| 741 |
/* Compressed clusters don't have QCOW_OFLAG_COPIED */
|
| 742 |
if (offset & QCOW_OFLAG_COPIED) {
|
| 743 |
fprintf(stderr, "ERROR: cluster %" PRId64 ": " |
| 744 |
"copied flag must never be set for compressed "
|
| 745 |
"clusters\n", offset >> s->cluster_bits);
|
| 746 |
offset &= ~QCOW_OFLAG_COPIED; |
| 747 |
errors++; |
| 748 |
} |
| 749 |
|
| 750 |
/* Mark cluster as used */
|
| 751 |
nb_csectors = ((offset >> s->csize_shift) & |
| 752 |
s->csize_mask) + 1;
|
| 753 |
offset &= s->cluster_offset_mask; |
| 754 |
errors += inc_refcounts(bs, refcount_table, |
| 755 |
refcount_table_size, |
| 756 |
offset & ~511, nb_csectors * 512); |
| 757 |
} else {
|
| 758 |
/* QCOW_OFLAG_COPIED must be set iff refcount == 1 */
|
| 759 |
if (check_copied) {
|
| 760 |
uint64_t entry = offset; |
| 761 |
offset &= ~QCOW_OFLAG_COPIED; |
| 762 |
refcount = get_refcount(bs, offset >> s->cluster_bits); |
| 763 |
if ((refcount == 1) != ((entry & QCOW_OFLAG_COPIED) != 0)) { |
| 764 |
fprintf(stderr, "ERROR OFLAG_COPIED: offset=%"
|
| 765 |
PRIx64 " refcount=%d\n", entry, refcount);
|
| 766 |
errors++; |
| 767 |
} |
| 768 |
} |
| 769 |
|
| 770 |
/* Mark cluster as used */
|
| 771 |
offset &= ~QCOW_OFLAG_COPIED; |
| 772 |
errors += inc_refcounts(bs, refcount_table, |
| 773 |
refcount_table_size, |
| 774 |
offset, s->cluster_size); |
| 775 |
|
| 776 |
/* Correct offsets are cluster aligned */
|
| 777 |
if (offset & (s->cluster_size - 1)) { |
| 778 |
fprintf(stderr, "ERROR offset=%" PRIx64 ": Cluster is not " |
| 779 |
"properly aligned; L2 entry corrupted.\n", offset);
|
| 780 |
errors++; |
| 781 |
} |
| 782 |
} |
| 783 |
} |
| 784 |
} |
| 785 |
|
| 786 |
qemu_free(l2_table); |
| 787 |
return errors;
|
| 788 |
|
| 789 |
fail:
|
| 790 |
fprintf(stderr, "ERROR: I/O error in check_refcounts_l1\n");
|
| 791 |
qemu_free(l2_table); |
| 792 |
return -EIO;
|
| 793 |
} |
| 794 |
|
| 795 |
/*
|
| 796 |
* Increases the refcount for the L1 table, its L2 tables and all referenced
|
| 797 |
* clusters in the given refcount table. While doing so, performs some checks
|
| 798 |
* on L1 and L2 entries.
|
| 799 |
*
|
| 800 |
* Returns the number of errors found by the checks or -errno if an internal
|
| 801 |
* error occurred.
|
| 802 |
*/
|
| 803 |
static int check_refcounts_l1(BlockDriverState *bs, |
| 804 |
uint16_t *refcount_table, |
| 805 |
int refcount_table_size,
|
| 806 |
int64_t l1_table_offset, int l1_size,
|
| 807 |
int check_copied)
|
| 808 |
{
|
| 809 |
BDRVQcowState *s = bs->opaque; |
| 810 |
uint64_t *l1_table, l2_offset, l1_size2; |
| 811 |
int i, refcount, ret;
|
| 812 |
int errors = 0; |
| 813 |
|
| 814 |
l1_size2 = l1_size * sizeof(uint64_t);
|
| 815 |
|
| 816 |
/* Mark L1 table as used */
|
| 817 |
errors += inc_refcounts(bs, refcount_table, refcount_table_size, |
| 818 |
l1_table_offset, l1_size2); |
| 819 |
|
| 820 |
/* Read L1 table entries from disk */
|
| 821 |
if (l1_size2 == 0) { |
| 822 |
l1_table = NULL;
|
| 823 |
} else {
|
| 824 |
l1_table = qemu_malloc(l1_size2); |
| 825 |
if (bdrv_pread(s->hd, l1_table_offset,
|
| 826 |
l1_table, l1_size2) != l1_size2) |
| 827 |
goto fail;
|
| 828 |
for(i = 0;i < l1_size; i++) |
| 829 |
be64_to_cpus(&l1_table[i]); |
| 830 |
} |
| 831 |
|
| 832 |
/* Do the actual checks */
|
| 833 |
for(i = 0; i < l1_size; i++) { |
| 834 |
l2_offset = l1_table[i]; |
| 835 |
if (l2_offset) {
|
| 836 |
/* QCOW_OFLAG_COPIED must be set iff refcount == 1 */
|
| 837 |
if (check_copied) {
|
| 838 |
refcount = get_refcount(bs, (l2_offset & ~QCOW_OFLAG_COPIED) |
| 839 |
>> s->cluster_bits); |
| 840 |
if ((refcount == 1) != ((l2_offset & QCOW_OFLAG_COPIED) != 0)) { |
| 841 |
fprintf(stderr, "ERROR OFLAG_COPIED: l2_offset=%" PRIx64
|
| 842 |
" refcount=%d\n", l2_offset, refcount);
|
| 843 |
errors++; |
| 844 |
} |
| 845 |
} |
| 846 |
|
| 847 |
/* Mark L2 table as used */
|
| 848 |
l2_offset &= ~QCOW_OFLAG_COPIED; |
| 849 |
errors += inc_refcounts(bs, refcount_table, |
| 850 |
refcount_table_size, |
| 851 |
l2_offset, |
| 852 |
s->cluster_size); |
| 853 |
|
| 854 |
/* L2 tables are cluster aligned */
|
| 855 |
if (l2_offset & (s->cluster_size - 1)) { |
| 856 |
fprintf(stderr, "ERROR l2_offset=%" PRIx64 ": Table is not " |
| 857 |
"cluster aligned; L1 entry corrupted\n", l2_offset);
|
| 858 |
errors++; |
| 859 |
} |
| 860 |
|
| 861 |
/* Process and check L2 entries */
|
| 862 |
ret = check_refcounts_l2(bs, refcount_table, refcount_table_size, |
| 863 |
l2_offset, check_copied); |
| 864 |
if (ret < 0) { |
| 865 |
goto fail;
|
| 866 |
} |
| 867 |
errors += ret; |
| 868 |
} |
| 869 |
} |
| 870 |
qemu_free(l1_table); |
| 871 |
return errors;
|
| 872 |
|
| 873 |
fail:
|
| 874 |
fprintf(stderr, "ERROR: I/O error in check_refcounts_l1\n");
|
| 875 |
qemu_free(l1_table); |
| 876 |
return -EIO;
|
| 877 |
} |
| 878 |
|
| 879 |
/*
|
| 880 |
* Checks an image for refcount consistency.
|
| 881 |
*
|
| 882 |
* Returns 0 if no errors are found, the number of errors in case the image is
|
| 883 |
* detected as corrupted, and -errno when an internal error occured.
|
| 884 |
*/
|
| 885 |
int qcow2_check_refcounts(BlockDriverState *bs)
|
| 886 |
{
|
| 887 |
BDRVQcowState *s = bs->opaque; |
| 888 |
int64_t size; |
| 889 |
int nb_clusters, refcount1, refcount2, i;
|
| 890 |
QCowSnapshot *sn; |
| 891 |
uint16_t *refcount_table; |
| 892 |
int ret, errors = 0; |
| 893 |
|
| 894 |
size = bdrv_getlength(s->hd); |
| 895 |
nb_clusters = size_to_clusters(s, size); |
| 896 |
refcount_table = qemu_mallocz(nb_clusters * sizeof(uint16_t));
|
| 897 |
|
| 898 |
/* header */
|
| 899 |
errors += inc_refcounts(bs, refcount_table, nb_clusters, |
| 900 |
0, s->cluster_size);
|
| 901 |
|
| 902 |
/* current L1 table */
|
| 903 |
ret = check_refcounts_l1(bs, refcount_table, nb_clusters, |
| 904 |
s->l1_table_offset, s->l1_size, 1);
|
| 905 |
if (ret < 0) { |
| 906 |
return ret;
|
| 907 |
} |
| 908 |
errors += ret; |
| 909 |
|
| 910 |
/* snapshots */
|
| 911 |
for(i = 0; i < s->nb_snapshots; i++) { |
| 912 |
sn = s->snapshots + i; |
| 913 |
check_refcounts_l1(bs, refcount_table, nb_clusters, |
| 914 |
sn->l1_table_offset, sn->l1_size, 0);
|
| 915 |
} |
| 916 |
errors += inc_refcounts(bs, refcount_table, nb_clusters, |
| 917 |
s->snapshots_offset, s->snapshots_size); |
| 918 |
|
| 919 |
/* refcount data */
|
| 920 |
errors += inc_refcounts(bs, refcount_table, nb_clusters, |
| 921 |
s->refcount_table_offset, |
| 922 |
s->refcount_table_size * sizeof(uint64_t));
|
| 923 |
for(i = 0; i < s->refcount_table_size; i++) { |
| 924 |
int64_t offset; |
| 925 |
offset = s->refcount_table[i]; |
| 926 |
if (offset != 0) { |
| 927 |
errors += inc_refcounts(bs, refcount_table, nb_clusters, |
| 928 |
offset, s->cluster_size); |
| 929 |
} |
| 930 |
} |
| 931 |
|
| 932 |
/* compare ref counts */
|
| 933 |
for(i = 0; i < nb_clusters; i++) { |
| 934 |
refcount1 = get_refcount(bs, i); |
| 935 |
refcount2 = refcount_table[i]; |
| 936 |
if (refcount1 != refcount2) {
|
| 937 |
fprintf(stderr, "ERROR cluster %d refcount=%d reference=%d\n",
|
| 938 |
i, refcount1, refcount2); |
| 939 |
errors++; |
| 940 |
} |
| 941 |
} |
| 942 |
|
| 943 |
qemu_free(refcount_table); |
| 944 |
|
| 945 |
return errors;
|
| 946 |
} |
| 947 |
|