root / block / qcow2-snapshot.c @ 737e150e
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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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|
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typedef struct QEMU_PACKED QCowSnapshotHeader { |
30 |
/* header is 8 byte aligned */
|
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uint64_t l1_table_offset; |
32 |
|
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uint32_t l1_size; |
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uint16_t id_str_size; |
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uint16_t name_size; |
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|
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uint32_t date_sec; |
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uint32_t date_nsec; |
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|
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uint64_t vm_clock_nsec; |
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|
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uint32_t vm_state_size; |
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uint32_t extra_data_size; /* for extension */
|
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/* extra data follows */
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/* id_str follows */
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/* name follows */
|
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} QCowSnapshotHeader; |
48 |
|
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typedef struct QEMU_PACKED QCowSnapshotExtraData { |
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uint64_t vm_state_size_large; |
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uint64_t disk_size; |
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} QCowSnapshotExtraData; |
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|
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void qcow2_free_snapshots(BlockDriverState *bs)
|
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{ |
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BDRVQcowState *s = bs->opaque; |
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int i;
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|
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for(i = 0; i < s->nb_snapshots; i++) { |
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g_free(s->snapshots[i].name); |
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g_free(s->snapshots[i].id_str); |
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} |
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g_free(s->snapshots); |
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s->snapshots = NULL;
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s->nb_snapshots = 0;
|
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} |
67 |
|
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int qcow2_read_snapshots(BlockDriverState *bs)
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{ |
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BDRVQcowState *s = bs->opaque; |
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QCowSnapshotHeader h; |
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QCowSnapshotExtraData extra; |
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QCowSnapshot *sn; |
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int i, id_str_size, name_size;
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int64_t offset; |
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uint32_t extra_data_size; |
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int ret;
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|
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if (!s->nb_snapshots) {
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s->snapshots = NULL;
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s->snapshots_size = 0;
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return 0; |
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} |
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|
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offset = s->snapshots_offset; |
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s->snapshots = g_malloc0(s->nb_snapshots * sizeof(QCowSnapshot));
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|
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for(i = 0; i < s->nb_snapshots; i++) { |
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/* Read statically sized part of the snapshot header */
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offset = align_offset(offset, 8);
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ret = bdrv_pread(bs->file, offset, &h, sizeof(h));
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if (ret < 0) { |
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goto fail;
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} |
95 |
|
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offset += sizeof(h);
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sn = s->snapshots + i; |
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sn->l1_table_offset = be64_to_cpu(h.l1_table_offset); |
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sn->l1_size = be32_to_cpu(h.l1_size); |
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sn->vm_state_size = be32_to_cpu(h.vm_state_size); |
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sn->date_sec = be32_to_cpu(h.date_sec); |
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sn->date_nsec = be32_to_cpu(h.date_nsec); |
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sn->vm_clock_nsec = be64_to_cpu(h.vm_clock_nsec); |
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extra_data_size = be32_to_cpu(h.extra_data_size); |
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|
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id_str_size = be16_to_cpu(h.id_str_size); |
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name_size = be16_to_cpu(h.name_size); |
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|
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/* Read extra data */
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ret = bdrv_pread(bs->file, offset, &extra, |
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MIN(sizeof(extra), extra_data_size));
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if (ret < 0) { |
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goto fail;
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} |
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offset += extra_data_size; |
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|
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if (extra_data_size >= 8) { |
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sn->vm_state_size = be64_to_cpu(extra.vm_state_size_large); |
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} |
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|
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if (extra_data_size >= 16) { |
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sn->disk_size = be64_to_cpu(extra.disk_size); |
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} else {
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sn->disk_size = bs->total_sectors * BDRV_SECTOR_SIZE; |
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} |
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|
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/* Read snapshot ID */
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sn->id_str = g_malloc(id_str_size + 1);
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ret = bdrv_pread(bs->file, offset, sn->id_str, id_str_size); |
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if (ret < 0) { |
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goto fail;
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} |
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offset += id_str_size; |
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sn->id_str[id_str_size] = '\0';
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|
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/* Read snapshot name */
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sn->name = g_malloc(name_size + 1);
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ret = bdrv_pread(bs->file, offset, sn->name, name_size); |
139 |
if (ret < 0) { |
140 |
goto fail;
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} |
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offset += name_size; |
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sn->name[name_size] = '\0';
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} |
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s->snapshots_size = offset - s->snapshots_offset; |
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return 0; |
148 |
|
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fail:
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qcow2_free_snapshots(bs); |
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return ret;
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} |
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|
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/* add at the end of the file a new list of snapshots */
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static int qcow2_write_snapshots(BlockDriverState *bs) |
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{ |
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BDRVQcowState *s = bs->opaque; |
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QCowSnapshot *sn; |
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QCowSnapshotHeader h; |
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QCowSnapshotExtraData extra; |
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int i, name_size, id_str_size, snapshots_size;
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struct {
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uint32_t nb_snapshots; |
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uint64_t snapshots_offset; |
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} QEMU_PACKED header_data; |
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int64_t offset, snapshots_offset; |
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int ret;
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|
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/* compute the size of the snapshots */
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offset = 0;
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for(i = 0; i < s->nb_snapshots; i++) { |
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sn = s->snapshots + i; |
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offset = align_offset(offset, 8);
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offset += sizeof(h);
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offset += sizeof(extra);
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offset += strlen(sn->id_str); |
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offset += strlen(sn->name); |
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} |
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snapshots_size = offset; |
180 |
|
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/* Allocate space for the new snapshot list */
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snapshots_offset = qcow2_alloc_clusters(bs, snapshots_size); |
183 |
bdrv_flush(bs->file); |
184 |
offset = snapshots_offset; |
185 |
if (offset < 0) { |
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return offset;
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} |
188 |
|
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/* Write all snapshots to the new list */
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for(i = 0; i < s->nb_snapshots; i++) { |
191 |
sn = s->snapshots + i; |
192 |
memset(&h, 0, sizeof(h)); |
193 |
h.l1_table_offset = cpu_to_be64(sn->l1_table_offset); |
194 |
h.l1_size = cpu_to_be32(sn->l1_size); |
195 |
/* If it doesn't fit in 32 bit, older implementations should treat it
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* as a disk-only snapshot rather than truncate the VM state */
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if (sn->vm_state_size <= 0xffffffff) { |
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h.vm_state_size = cpu_to_be32(sn->vm_state_size); |
199 |
} |
200 |
h.date_sec = cpu_to_be32(sn->date_sec); |
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h.date_nsec = cpu_to_be32(sn->date_nsec); |
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h.vm_clock_nsec = cpu_to_be64(sn->vm_clock_nsec); |
203 |
h.extra_data_size = cpu_to_be32(sizeof(extra));
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|
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memset(&extra, 0, sizeof(extra)); |
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extra.vm_state_size_large = cpu_to_be64(sn->vm_state_size); |
207 |
extra.disk_size = cpu_to_be64(sn->disk_size); |
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|
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id_str_size = strlen(sn->id_str); |
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name_size = strlen(sn->name); |
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h.id_str_size = cpu_to_be16(id_str_size); |
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h.name_size = cpu_to_be16(name_size); |
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offset = align_offset(offset, 8);
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ret = bdrv_pwrite(bs->file, offset, &h, sizeof(h));
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216 |
if (ret < 0) { |
217 |
goto fail;
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} |
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offset += sizeof(h);
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220 |
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ret = bdrv_pwrite(bs->file, offset, &extra, sizeof(extra));
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if (ret < 0) { |
223 |
goto fail;
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} |
225 |
offset += sizeof(extra);
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226 |
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ret = bdrv_pwrite(bs->file, offset, sn->id_str, id_str_size); |
228 |
if (ret < 0) { |
229 |
goto fail;
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230 |
} |
231 |
offset += id_str_size; |
232 |
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ret = bdrv_pwrite(bs->file, offset, sn->name, name_size); |
234 |
if (ret < 0) { |
235 |
goto fail;
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236 |
} |
237 |
offset += name_size; |
238 |
} |
239 |
|
240 |
/*
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241 |
* Update the header to point to the new snapshot table. This requires the
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* new table and its refcounts to be stable on disk.
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*/
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ret = bdrv_flush(bs); |
245 |
if (ret < 0) { |
246 |
goto fail;
|
247 |
} |
248 |
|
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QEMU_BUILD_BUG_ON(offsetof(QCowHeader, snapshots_offset) != |
250 |
offsetof(QCowHeader, nb_snapshots) + sizeof(header_data.nb_snapshots));
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|
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header_data.nb_snapshots = cpu_to_be32(s->nb_snapshots); |
253 |
header_data.snapshots_offset = cpu_to_be64(snapshots_offset); |
254 |
|
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ret = bdrv_pwrite_sync(bs->file, offsetof(QCowHeader, nb_snapshots), |
256 |
&header_data, sizeof(header_data));
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257 |
if (ret < 0) { |
258 |
goto fail;
|
259 |
} |
260 |
|
261 |
/* free the old snapshot table */
|
262 |
qcow2_free_clusters(bs, s->snapshots_offset, s->snapshots_size); |
263 |
s->snapshots_offset = snapshots_offset; |
264 |
s->snapshots_size = snapshots_size; |
265 |
return 0; |
266 |
|
267 |
fail:
|
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return ret;
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} |
270 |
|
271 |
static void find_new_snapshot_id(BlockDriverState *bs, |
272 |
char *id_str, int id_str_size) |
273 |
{ |
274 |
BDRVQcowState *s = bs->opaque; |
275 |
QCowSnapshot *sn; |
276 |
int i, id, id_max = 0; |
277 |
|
278 |
for(i = 0; i < s->nb_snapshots; i++) { |
279 |
sn = s->snapshots + i; |
280 |
id = strtoul(sn->id_str, NULL, 10); |
281 |
if (id > id_max)
|
282 |
id_max = id; |
283 |
} |
284 |
snprintf(id_str, id_str_size, "%d", id_max + 1); |
285 |
} |
286 |
|
287 |
static int find_snapshot_by_id(BlockDriverState *bs, const char *id_str) |
288 |
{ |
289 |
BDRVQcowState *s = bs->opaque; |
290 |
int i;
|
291 |
|
292 |
for(i = 0; i < s->nb_snapshots; i++) { |
293 |
if (!strcmp(s->snapshots[i].id_str, id_str))
|
294 |
return i;
|
295 |
} |
296 |
return -1; |
297 |
} |
298 |
|
299 |
static int find_snapshot_by_id_or_name(BlockDriverState *bs, const char *name) |
300 |
{ |
301 |
BDRVQcowState *s = bs->opaque; |
302 |
int i, ret;
|
303 |
|
304 |
ret = find_snapshot_by_id(bs, name); |
305 |
if (ret >= 0) |
306 |
return ret;
|
307 |
for(i = 0; i < s->nb_snapshots; i++) { |
308 |
if (!strcmp(s->snapshots[i].name, name))
|
309 |
return i;
|
310 |
} |
311 |
return -1; |
312 |
} |
313 |
|
314 |
/* if no id is provided, a new one is constructed */
|
315 |
int qcow2_snapshot_create(BlockDriverState *bs, QEMUSnapshotInfo *sn_info)
|
316 |
{ |
317 |
BDRVQcowState *s = bs->opaque; |
318 |
QCowSnapshot *new_snapshot_list = NULL;
|
319 |
QCowSnapshot *old_snapshot_list = NULL;
|
320 |
QCowSnapshot sn1, *sn = &sn1; |
321 |
int i, ret;
|
322 |
uint64_t *l1_table = NULL;
|
323 |
int64_t l1_table_offset; |
324 |
|
325 |
memset(sn, 0, sizeof(*sn)); |
326 |
|
327 |
/* Generate an ID if it wasn't passed */
|
328 |
if (sn_info->id_str[0] == '\0') { |
329 |
find_new_snapshot_id(bs, sn_info->id_str, sizeof(sn_info->id_str));
|
330 |
} |
331 |
|
332 |
/* Check that the ID is unique */
|
333 |
if (find_snapshot_by_id(bs, sn_info->id_str) >= 0) { |
334 |
return -EEXIST;
|
335 |
} |
336 |
|
337 |
/* Populate sn with passed data */
|
338 |
sn->id_str = g_strdup(sn_info->id_str); |
339 |
sn->name = g_strdup(sn_info->name); |
340 |
|
341 |
sn->disk_size = bs->total_sectors * BDRV_SECTOR_SIZE; |
342 |
sn->vm_state_size = sn_info->vm_state_size; |
343 |
sn->date_sec = sn_info->date_sec; |
344 |
sn->date_nsec = sn_info->date_nsec; |
345 |
sn->vm_clock_nsec = sn_info->vm_clock_nsec; |
346 |
|
347 |
/* Allocate the L1 table of the snapshot and copy the current one there. */
|
348 |
l1_table_offset = qcow2_alloc_clusters(bs, s->l1_size * sizeof(uint64_t));
|
349 |
if (l1_table_offset < 0) { |
350 |
ret = l1_table_offset; |
351 |
goto fail;
|
352 |
} |
353 |
|
354 |
sn->l1_table_offset = l1_table_offset; |
355 |
sn->l1_size = s->l1_size; |
356 |
|
357 |
l1_table = g_malloc(s->l1_size * sizeof(uint64_t));
|
358 |
for(i = 0; i < s->l1_size; i++) { |
359 |
l1_table[i] = cpu_to_be64(s->l1_table[i]); |
360 |
} |
361 |
|
362 |
ret = bdrv_pwrite(bs->file, sn->l1_table_offset, l1_table, |
363 |
s->l1_size * sizeof(uint64_t));
|
364 |
if (ret < 0) { |
365 |
goto fail;
|
366 |
} |
367 |
|
368 |
g_free(l1_table); |
369 |
l1_table = NULL;
|
370 |
|
371 |
/*
|
372 |
* Increase the refcounts of all clusters and make sure everything is
|
373 |
* stable on disk before updating the snapshot table to contain a pointer
|
374 |
* to the new L1 table.
|
375 |
*/
|
376 |
ret = qcow2_update_snapshot_refcount(bs, s->l1_table_offset, s->l1_size, 1);
|
377 |
if (ret < 0) { |
378 |
goto fail;
|
379 |
} |
380 |
|
381 |
ret = bdrv_flush(bs); |
382 |
if (ret < 0) { |
383 |
goto fail;
|
384 |
} |
385 |
|
386 |
/* Append the new snapshot to the snapshot list */
|
387 |
new_snapshot_list = g_malloc((s->nb_snapshots + 1) * sizeof(QCowSnapshot)); |
388 |
if (s->snapshots) {
|
389 |
memcpy(new_snapshot_list, s->snapshots, |
390 |
s->nb_snapshots * sizeof(QCowSnapshot));
|
391 |
old_snapshot_list = s->snapshots; |
392 |
} |
393 |
s->snapshots = new_snapshot_list; |
394 |
s->snapshots[s->nb_snapshots++] = *sn; |
395 |
|
396 |
ret = qcow2_write_snapshots(bs); |
397 |
if (ret < 0) { |
398 |
g_free(s->snapshots); |
399 |
s->snapshots = old_snapshot_list; |
400 |
goto fail;
|
401 |
} |
402 |
|
403 |
g_free(old_snapshot_list); |
404 |
|
405 |
#ifdef DEBUG_ALLOC
|
406 |
{ |
407 |
BdrvCheckResult result = {0};
|
408 |
qcow2_check_refcounts(bs, &result, 0);
|
409 |
} |
410 |
#endif
|
411 |
return 0; |
412 |
|
413 |
fail:
|
414 |
g_free(sn->id_str); |
415 |
g_free(sn->name); |
416 |
g_free(l1_table); |
417 |
|
418 |
return ret;
|
419 |
} |
420 |
|
421 |
/* copy the snapshot 'snapshot_name' into the current disk image */
|
422 |
int qcow2_snapshot_goto(BlockDriverState *bs, const char *snapshot_id) |
423 |
{ |
424 |
BDRVQcowState *s = bs->opaque; |
425 |
QCowSnapshot *sn; |
426 |
int i, snapshot_index;
|
427 |
int cur_l1_bytes, sn_l1_bytes;
|
428 |
int ret;
|
429 |
uint64_t *sn_l1_table = NULL;
|
430 |
|
431 |
/* Search the snapshot */
|
432 |
snapshot_index = find_snapshot_by_id_or_name(bs, snapshot_id); |
433 |
if (snapshot_index < 0) { |
434 |
return -ENOENT;
|
435 |
} |
436 |
sn = &s->snapshots[snapshot_index]; |
437 |
|
438 |
if (sn->disk_size != bs->total_sectors * BDRV_SECTOR_SIZE) {
|
439 |
error_report("qcow2: Loading snapshots with different disk "
|
440 |
"size is not implemented");
|
441 |
ret = -ENOTSUP; |
442 |
goto fail;
|
443 |
} |
444 |
|
445 |
/*
|
446 |
* Make sure that the current L1 table is big enough to contain the whole
|
447 |
* L1 table of the snapshot. If the snapshot L1 table is smaller, the
|
448 |
* current one must be padded with zeros.
|
449 |
*/
|
450 |
ret = qcow2_grow_l1_table(bs, sn->l1_size, true);
|
451 |
if (ret < 0) { |
452 |
goto fail;
|
453 |
} |
454 |
|
455 |
cur_l1_bytes = s->l1_size * sizeof(uint64_t);
|
456 |
sn_l1_bytes = sn->l1_size * sizeof(uint64_t);
|
457 |
|
458 |
/*
|
459 |
* Copy the snapshot L1 table to the current L1 table.
|
460 |
*
|
461 |
* Before overwriting the old current L1 table on disk, make sure to
|
462 |
* increase all refcounts for the clusters referenced by the new one.
|
463 |
* Decrease the refcount referenced by the old one only when the L1
|
464 |
* table is overwritten.
|
465 |
*/
|
466 |
sn_l1_table = g_malloc0(cur_l1_bytes); |
467 |
|
468 |
ret = bdrv_pread(bs->file, sn->l1_table_offset, sn_l1_table, sn_l1_bytes); |
469 |
if (ret < 0) { |
470 |
goto fail;
|
471 |
} |
472 |
|
473 |
ret = qcow2_update_snapshot_refcount(bs, sn->l1_table_offset, |
474 |
sn->l1_size, 1);
|
475 |
if (ret < 0) { |
476 |
goto fail;
|
477 |
} |
478 |
|
479 |
ret = bdrv_pwrite_sync(bs->file, s->l1_table_offset, sn_l1_table, |
480 |
cur_l1_bytes); |
481 |
if (ret < 0) { |
482 |
goto fail;
|
483 |
} |
484 |
|
485 |
/*
|
486 |
* Decrease refcount of clusters of current L1 table.
|
487 |
*
|
488 |
* At this point, the in-memory s->l1_table points to the old L1 table,
|
489 |
* whereas on disk we already have the new one.
|
490 |
*
|
491 |
* qcow2_update_snapshot_refcount special cases the current L1 table to use
|
492 |
* the in-memory data instead of really using the offset to load a new one,
|
493 |
* which is why this works.
|
494 |
*/
|
495 |
ret = qcow2_update_snapshot_refcount(bs, s->l1_table_offset, |
496 |
s->l1_size, -1);
|
497 |
|
498 |
/*
|
499 |
* Now update the in-memory L1 table to be in sync with the on-disk one. We
|
500 |
* need to do this even if updating refcounts failed.
|
501 |
*/
|
502 |
for(i = 0;i < s->l1_size; i++) { |
503 |
s->l1_table[i] = be64_to_cpu(sn_l1_table[i]); |
504 |
} |
505 |
|
506 |
if (ret < 0) { |
507 |
goto fail;
|
508 |
} |
509 |
|
510 |
g_free(sn_l1_table); |
511 |
sn_l1_table = NULL;
|
512 |
|
513 |
/*
|
514 |
* Update QCOW_OFLAG_COPIED in the active L1 table (it may have changed
|
515 |
* when we decreased the refcount of the old snapshot.
|
516 |
*/
|
517 |
ret = qcow2_update_snapshot_refcount(bs, s->l1_table_offset, s->l1_size, 0);
|
518 |
if (ret < 0) { |
519 |
goto fail;
|
520 |
} |
521 |
|
522 |
#ifdef DEBUG_ALLOC
|
523 |
{ |
524 |
BdrvCheckResult result = {0};
|
525 |
qcow2_check_refcounts(bs, &result, 0);
|
526 |
} |
527 |
#endif
|
528 |
return 0; |
529 |
|
530 |
fail:
|
531 |
g_free(sn_l1_table); |
532 |
return ret;
|
533 |
} |
534 |
|
535 |
int qcow2_snapshot_delete(BlockDriverState *bs, const char *snapshot_id) |
536 |
{ |
537 |
BDRVQcowState *s = bs->opaque; |
538 |
QCowSnapshot sn; |
539 |
int snapshot_index, ret;
|
540 |
|
541 |
/* Search the snapshot */
|
542 |
snapshot_index = find_snapshot_by_id_or_name(bs, snapshot_id); |
543 |
if (snapshot_index < 0) { |
544 |
return -ENOENT;
|
545 |
} |
546 |
sn = s->snapshots[snapshot_index]; |
547 |
|
548 |
/* Remove it from the snapshot list */
|
549 |
memmove(s->snapshots + snapshot_index, |
550 |
s->snapshots + snapshot_index + 1,
|
551 |
(s->nb_snapshots - snapshot_index - 1) * sizeof(sn)); |
552 |
s->nb_snapshots--; |
553 |
ret = qcow2_write_snapshots(bs); |
554 |
if (ret < 0) { |
555 |
return ret;
|
556 |
} |
557 |
|
558 |
/*
|
559 |
* The snapshot is now unused, clean up. If we fail after this point, we
|
560 |
* won't recover but just leak clusters.
|
561 |
*/
|
562 |
g_free(sn.id_str); |
563 |
g_free(sn.name); |
564 |
|
565 |
/*
|
566 |
* Now decrease the refcounts of clusters referenced by the snapshot and
|
567 |
* free the L1 table.
|
568 |
*/
|
569 |
ret = qcow2_update_snapshot_refcount(bs, sn.l1_table_offset, |
570 |
sn.l1_size, -1);
|
571 |
if (ret < 0) { |
572 |
return ret;
|
573 |
} |
574 |
qcow2_free_clusters(bs, sn.l1_table_offset, sn.l1_size * sizeof(uint64_t));
|
575 |
|
576 |
/* must update the copied flag on the current cluster offsets */
|
577 |
ret = qcow2_update_snapshot_refcount(bs, s->l1_table_offset, s->l1_size, 0);
|
578 |
if (ret < 0) { |
579 |
return ret;
|
580 |
} |
581 |
|
582 |
#ifdef DEBUG_ALLOC
|
583 |
{ |
584 |
BdrvCheckResult result = {0};
|
585 |
qcow2_check_refcounts(bs, &result, 0);
|
586 |
} |
587 |
#endif
|
588 |
return 0; |
589 |
} |
590 |
|
591 |
int qcow2_snapshot_list(BlockDriverState *bs, QEMUSnapshotInfo **psn_tab)
|
592 |
{ |
593 |
BDRVQcowState *s = bs->opaque; |
594 |
QEMUSnapshotInfo *sn_tab, *sn_info; |
595 |
QCowSnapshot *sn; |
596 |
int i;
|
597 |
|
598 |
if (!s->nb_snapshots) {
|
599 |
*psn_tab = NULL;
|
600 |
return s->nb_snapshots;
|
601 |
} |
602 |
|
603 |
sn_tab = g_malloc0(s->nb_snapshots * sizeof(QEMUSnapshotInfo));
|
604 |
for(i = 0; i < s->nb_snapshots; i++) { |
605 |
sn_info = sn_tab + i; |
606 |
sn = s->snapshots + i; |
607 |
pstrcpy(sn_info->id_str, sizeof(sn_info->id_str),
|
608 |
sn->id_str); |
609 |
pstrcpy(sn_info->name, sizeof(sn_info->name),
|
610 |
sn->name); |
611 |
sn_info->vm_state_size = sn->vm_state_size; |
612 |
sn_info->date_sec = sn->date_sec; |
613 |
sn_info->date_nsec = sn->date_nsec; |
614 |
sn_info->vm_clock_nsec = sn->vm_clock_nsec; |
615 |
} |
616 |
*psn_tab = sn_tab; |
617 |
return s->nb_snapshots;
|
618 |
} |
619 |
|
620 |
int qcow2_snapshot_load_tmp(BlockDriverState *bs, const char *snapshot_name) |
621 |
{ |
622 |
int i, snapshot_index;
|
623 |
BDRVQcowState *s = bs->opaque; |
624 |
QCowSnapshot *sn; |
625 |
uint64_t *new_l1_table; |
626 |
int new_l1_bytes;
|
627 |
int ret;
|
628 |
|
629 |
assert(bs->read_only); |
630 |
|
631 |
/* Search the snapshot */
|
632 |
snapshot_index = find_snapshot_by_id_or_name(bs, snapshot_name); |
633 |
if (snapshot_index < 0) { |
634 |
return -ENOENT;
|
635 |
} |
636 |
sn = &s->snapshots[snapshot_index]; |
637 |
|
638 |
/* Allocate and read in the snapshot's L1 table */
|
639 |
new_l1_bytes = s->l1_size * sizeof(uint64_t);
|
640 |
new_l1_table = g_malloc0(align_offset(new_l1_bytes, 512));
|
641 |
|
642 |
ret = bdrv_pread(bs->file, sn->l1_table_offset, new_l1_table, new_l1_bytes); |
643 |
if (ret < 0) { |
644 |
g_free(new_l1_table); |
645 |
return ret;
|
646 |
} |
647 |
|
648 |
/* Switch the L1 table */
|
649 |
g_free(s->l1_table); |
650 |
|
651 |
s->l1_size = sn->l1_size; |
652 |
s->l1_table_offset = sn->l1_table_offset; |
653 |
s->l1_table = new_l1_table; |
654 |
|
655 |
for(i = 0;i < s->l1_size; i++) { |
656 |
be64_to_cpus(&s->l1_table[i]); |
657 |
} |
658 |
|
659 |
return 0; |
660 |
} |