9e029689e1
The align_offset() function is equivalent to the ROUND_UP() macro so there's no need to use the former. The ROUND_UP() name is also a bit more explicit. This patch uses ROUND_UP() instead of the slower QEMU_ALIGN_UP() because align_offset() already requires that the second parameter is a power of two. Signed-off-by: Alberto Garcia <berto@igalia.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org> Message-id: 20180215131008.5153-1-berto@igalia.com Signed-off-by: Max Reitz <mreitz@redhat.com>
739 lines
21 KiB
C
739 lines
21 KiB
C
/*
|
|
* Block driver for the QCOW version 2 format
|
|
*
|
|
* Copyright (c) 2004-2006 Fabrice Bellard
|
|
*
|
|
* Permission is hereby granted, free of charge, to any person obtaining a copy
|
|
* of this software and associated documentation files (the "Software"), to deal
|
|
* in the Software without restriction, including without limitation the rights
|
|
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
|
|
* copies of the Software, and to permit persons to whom the Software is
|
|
* furnished to do so, subject to the following conditions:
|
|
*
|
|
* The above copyright notice and this permission notice shall be included in
|
|
* all copies or substantial portions of the Software.
|
|
*
|
|
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
|
|
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
|
|
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
|
|
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
|
|
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
|
|
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
|
|
* THE SOFTWARE.
|
|
*/
|
|
|
|
#include "qemu/osdep.h"
|
|
#include "qapi/error.h"
|
|
#include "block/block_int.h"
|
|
#include "block/qcow2.h"
|
|
#include "qemu/bswap.h"
|
|
#include "qemu/error-report.h"
|
|
#include "qemu/cutils.h"
|
|
|
|
void qcow2_free_snapshots(BlockDriverState *bs)
|
|
{
|
|
BDRVQcow2State *s = bs->opaque;
|
|
int i;
|
|
|
|
for(i = 0; i < s->nb_snapshots; i++) {
|
|
g_free(s->snapshots[i].name);
|
|
g_free(s->snapshots[i].id_str);
|
|
}
|
|
g_free(s->snapshots);
|
|
s->snapshots = NULL;
|
|
s->nb_snapshots = 0;
|
|
}
|
|
|
|
int qcow2_read_snapshots(BlockDriverState *bs)
|
|
{
|
|
BDRVQcow2State *s = bs->opaque;
|
|
QCowSnapshotHeader h;
|
|
QCowSnapshotExtraData extra;
|
|
QCowSnapshot *sn;
|
|
int i, id_str_size, name_size;
|
|
int64_t offset;
|
|
uint32_t extra_data_size;
|
|
int ret;
|
|
|
|
if (!s->nb_snapshots) {
|
|
s->snapshots = NULL;
|
|
s->snapshots_size = 0;
|
|
return 0;
|
|
}
|
|
|
|
offset = s->snapshots_offset;
|
|
s->snapshots = g_new0(QCowSnapshot, s->nb_snapshots);
|
|
|
|
for(i = 0; i < s->nb_snapshots; i++) {
|
|
/* Read statically sized part of the snapshot header */
|
|
offset = ROUND_UP(offset, 8);
|
|
ret = bdrv_pread(bs->file, offset, &h, sizeof(h));
|
|
if (ret < 0) {
|
|
goto fail;
|
|
}
|
|
|
|
offset += sizeof(h);
|
|
sn = s->snapshots + i;
|
|
sn->l1_table_offset = be64_to_cpu(h.l1_table_offset);
|
|
sn->l1_size = be32_to_cpu(h.l1_size);
|
|
sn->vm_state_size = be32_to_cpu(h.vm_state_size);
|
|
sn->date_sec = be32_to_cpu(h.date_sec);
|
|
sn->date_nsec = be32_to_cpu(h.date_nsec);
|
|
sn->vm_clock_nsec = be64_to_cpu(h.vm_clock_nsec);
|
|
extra_data_size = be32_to_cpu(h.extra_data_size);
|
|
|
|
id_str_size = be16_to_cpu(h.id_str_size);
|
|
name_size = be16_to_cpu(h.name_size);
|
|
|
|
/* Read extra data */
|
|
ret = bdrv_pread(bs->file, offset, &extra,
|
|
MIN(sizeof(extra), extra_data_size));
|
|
if (ret < 0) {
|
|
goto fail;
|
|
}
|
|
offset += extra_data_size;
|
|
|
|
if (extra_data_size >= 8) {
|
|
sn->vm_state_size = be64_to_cpu(extra.vm_state_size_large);
|
|
}
|
|
|
|
if (extra_data_size >= 16) {
|
|
sn->disk_size = be64_to_cpu(extra.disk_size);
|
|
} else {
|
|
sn->disk_size = bs->total_sectors * BDRV_SECTOR_SIZE;
|
|
}
|
|
|
|
/* Read snapshot ID */
|
|
sn->id_str = g_malloc(id_str_size + 1);
|
|
ret = bdrv_pread(bs->file, offset, sn->id_str, id_str_size);
|
|
if (ret < 0) {
|
|
goto fail;
|
|
}
|
|
offset += id_str_size;
|
|
sn->id_str[id_str_size] = '\0';
|
|
|
|
/* Read snapshot name */
|
|
sn->name = g_malloc(name_size + 1);
|
|
ret = bdrv_pread(bs->file, offset, sn->name, name_size);
|
|
if (ret < 0) {
|
|
goto fail;
|
|
}
|
|
offset += name_size;
|
|
sn->name[name_size] = '\0';
|
|
|
|
if (offset - s->snapshots_offset > QCOW_MAX_SNAPSHOTS_SIZE) {
|
|
ret = -EFBIG;
|
|
goto fail;
|
|
}
|
|
}
|
|
|
|
assert(offset - s->snapshots_offset <= INT_MAX);
|
|
s->snapshots_size = offset - s->snapshots_offset;
|
|
return 0;
|
|
|
|
fail:
|
|
qcow2_free_snapshots(bs);
|
|
return ret;
|
|
}
|
|
|
|
/* add at the end of the file a new list of snapshots */
|
|
static int qcow2_write_snapshots(BlockDriverState *bs)
|
|
{
|
|
BDRVQcow2State *s = bs->opaque;
|
|
QCowSnapshot *sn;
|
|
QCowSnapshotHeader h;
|
|
QCowSnapshotExtraData extra;
|
|
int i, name_size, id_str_size, snapshots_size;
|
|
struct {
|
|
uint32_t nb_snapshots;
|
|
uint64_t snapshots_offset;
|
|
} QEMU_PACKED header_data;
|
|
int64_t offset, snapshots_offset = 0;
|
|
int ret;
|
|
|
|
/* compute the size of the snapshots */
|
|
offset = 0;
|
|
for(i = 0; i < s->nb_snapshots; i++) {
|
|
sn = s->snapshots + i;
|
|
offset = ROUND_UP(offset, 8);
|
|
offset += sizeof(h);
|
|
offset += sizeof(extra);
|
|
offset += strlen(sn->id_str);
|
|
offset += strlen(sn->name);
|
|
|
|
if (offset > QCOW_MAX_SNAPSHOTS_SIZE) {
|
|
ret = -EFBIG;
|
|
goto fail;
|
|
}
|
|
}
|
|
|
|
assert(offset <= INT_MAX);
|
|
snapshots_size = offset;
|
|
|
|
/* Allocate space for the new snapshot list */
|
|
snapshots_offset = qcow2_alloc_clusters(bs, snapshots_size);
|
|
offset = snapshots_offset;
|
|
if (offset < 0) {
|
|
ret = offset;
|
|
goto fail;
|
|
}
|
|
ret = bdrv_flush(bs);
|
|
if (ret < 0) {
|
|
goto fail;
|
|
}
|
|
|
|
/* The snapshot list position has not yet been updated, so these clusters
|
|
* must indeed be completely free */
|
|
ret = qcow2_pre_write_overlap_check(bs, 0, offset, snapshots_size);
|
|
if (ret < 0) {
|
|
goto fail;
|
|
}
|
|
|
|
|
|
/* Write all snapshots to the new list */
|
|
for(i = 0; i < s->nb_snapshots; i++) {
|
|
sn = s->snapshots + i;
|
|
memset(&h, 0, sizeof(h));
|
|
h.l1_table_offset = cpu_to_be64(sn->l1_table_offset);
|
|
h.l1_size = cpu_to_be32(sn->l1_size);
|
|
/* If it doesn't fit in 32 bit, older implementations should treat it
|
|
* as a disk-only snapshot rather than truncate the VM state */
|
|
if (sn->vm_state_size <= 0xffffffff) {
|
|
h.vm_state_size = cpu_to_be32(sn->vm_state_size);
|
|
}
|
|
h.date_sec = cpu_to_be32(sn->date_sec);
|
|
h.date_nsec = cpu_to_be32(sn->date_nsec);
|
|
h.vm_clock_nsec = cpu_to_be64(sn->vm_clock_nsec);
|
|
h.extra_data_size = cpu_to_be32(sizeof(extra));
|
|
|
|
memset(&extra, 0, sizeof(extra));
|
|
extra.vm_state_size_large = cpu_to_be64(sn->vm_state_size);
|
|
extra.disk_size = cpu_to_be64(sn->disk_size);
|
|
|
|
id_str_size = strlen(sn->id_str);
|
|
name_size = strlen(sn->name);
|
|
assert(id_str_size <= UINT16_MAX && name_size <= UINT16_MAX);
|
|
h.id_str_size = cpu_to_be16(id_str_size);
|
|
h.name_size = cpu_to_be16(name_size);
|
|
offset = ROUND_UP(offset, 8);
|
|
|
|
ret = bdrv_pwrite(bs->file, offset, &h, sizeof(h));
|
|
if (ret < 0) {
|
|
goto fail;
|
|
}
|
|
offset += sizeof(h);
|
|
|
|
ret = bdrv_pwrite(bs->file, offset, &extra, sizeof(extra));
|
|
if (ret < 0) {
|
|
goto fail;
|
|
}
|
|
offset += sizeof(extra);
|
|
|
|
ret = bdrv_pwrite(bs->file, offset, sn->id_str, id_str_size);
|
|
if (ret < 0) {
|
|
goto fail;
|
|
}
|
|
offset += id_str_size;
|
|
|
|
ret = bdrv_pwrite(bs->file, offset, sn->name, name_size);
|
|
if (ret < 0) {
|
|
goto fail;
|
|
}
|
|
offset += name_size;
|
|
}
|
|
|
|
/*
|
|
* Update the header to point to the new snapshot table. This requires the
|
|
* new table and its refcounts to be stable on disk.
|
|
*/
|
|
ret = bdrv_flush(bs);
|
|
if (ret < 0) {
|
|
goto fail;
|
|
}
|
|
|
|
QEMU_BUILD_BUG_ON(offsetof(QCowHeader, snapshots_offset) !=
|
|
offsetof(QCowHeader, nb_snapshots) + sizeof(header_data.nb_snapshots));
|
|
|
|
header_data.nb_snapshots = cpu_to_be32(s->nb_snapshots);
|
|
header_data.snapshots_offset = cpu_to_be64(snapshots_offset);
|
|
|
|
ret = bdrv_pwrite_sync(bs->file, offsetof(QCowHeader, nb_snapshots),
|
|
&header_data, sizeof(header_data));
|
|
if (ret < 0) {
|
|
goto fail;
|
|
}
|
|
|
|
/* free the old snapshot table */
|
|
qcow2_free_clusters(bs, s->snapshots_offset, s->snapshots_size,
|
|
QCOW2_DISCARD_SNAPSHOT);
|
|
s->snapshots_offset = snapshots_offset;
|
|
s->snapshots_size = snapshots_size;
|
|
return 0;
|
|
|
|
fail:
|
|
if (snapshots_offset > 0) {
|
|
qcow2_free_clusters(bs, snapshots_offset, snapshots_size,
|
|
QCOW2_DISCARD_ALWAYS);
|
|
}
|
|
return ret;
|
|
}
|
|
|
|
static void find_new_snapshot_id(BlockDriverState *bs,
|
|
char *id_str, int id_str_size)
|
|
{
|
|
BDRVQcow2State *s = bs->opaque;
|
|
QCowSnapshot *sn;
|
|
int i;
|
|
unsigned long id, id_max = 0;
|
|
|
|
for(i = 0; i < s->nb_snapshots; i++) {
|
|
sn = s->snapshots + i;
|
|
id = strtoul(sn->id_str, NULL, 10);
|
|
if (id > id_max)
|
|
id_max = id;
|
|
}
|
|
snprintf(id_str, id_str_size, "%lu", id_max + 1);
|
|
}
|
|
|
|
static int find_snapshot_by_id_and_name(BlockDriverState *bs,
|
|
const char *id,
|
|
const char *name)
|
|
{
|
|
BDRVQcow2State *s = bs->opaque;
|
|
int i;
|
|
|
|
if (id && name) {
|
|
for (i = 0; i < s->nb_snapshots; i++) {
|
|
if (!strcmp(s->snapshots[i].id_str, id) &&
|
|
!strcmp(s->snapshots[i].name, name)) {
|
|
return i;
|
|
}
|
|
}
|
|
} else if (id) {
|
|
for (i = 0; i < s->nb_snapshots; i++) {
|
|
if (!strcmp(s->snapshots[i].id_str, id)) {
|
|
return i;
|
|
}
|
|
}
|
|
} else if (name) {
|
|
for (i = 0; i < s->nb_snapshots; i++) {
|
|
if (!strcmp(s->snapshots[i].name, name)) {
|
|
return i;
|
|
}
|
|
}
|
|
}
|
|
|
|
return -1;
|
|
}
|
|
|
|
static int find_snapshot_by_id_or_name(BlockDriverState *bs,
|
|
const char *id_or_name)
|
|
{
|
|
int ret;
|
|
|
|
ret = find_snapshot_by_id_and_name(bs, id_or_name, NULL);
|
|
if (ret >= 0) {
|
|
return ret;
|
|
}
|
|
return find_snapshot_by_id_and_name(bs, NULL, id_or_name);
|
|
}
|
|
|
|
/* if no id is provided, a new one is constructed */
|
|
int qcow2_snapshot_create(BlockDriverState *bs, QEMUSnapshotInfo *sn_info)
|
|
{
|
|
BDRVQcow2State *s = bs->opaque;
|
|
QCowSnapshot *new_snapshot_list = NULL;
|
|
QCowSnapshot *old_snapshot_list = NULL;
|
|
QCowSnapshot sn1, *sn = &sn1;
|
|
int i, ret;
|
|
uint64_t *l1_table = NULL;
|
|
int64_t l1_table_offset;
|
|
|
|
if (s->nb_snapshots >= QCOW_MAX_SNAPSHOTS) {
|
|
return -EFBIG;
|
|
}
|
|
|
|
memset(sn, 0, sizeof(*sn));
|
|
|
|
/* Generate an ID */
|
|
find_new_snapshot_id(bs, sn_info->id_str, sizeof(sn_info->id_str));
|
|
|
|
/* Check that the ID is unique */
|
|
if (find_snapshot_by_id_and_name(bs, sn_info->id_str, NULL) >= 0) {
|
|
return -EEXIST;
|
|
}
|
|
|
|
/* Populate sn with passed data */
|
|
sn->id_str = g_strdup(sn_info->id_str);
|
|
sn->name = g_strdup(sn_info->name);
|
|
|
|
sn->disk_size = bs->total_sectors * BDRV_SECTOR_SIZE;
|
|
sn->vm_state_size = sn_info->vm_state_size;
|
|
sn->date_sec = sn_info->date_sec;
|
|
sn->date_nsec = sn_info->date_nsec;
|
|
sn->vm_clock_nsec = sn_info->vm_clock_nsec;
|
|
|
|
/* Allocate the L1 table of the snapshot and copy the current one there. */
|
|
l1_table_offset = qcow2_alloc_clusters(bs, s->l1_size * sizeof(uint64_t));
|
|
if (l1_table_offset < 0) {
|
|
ret = l1_table_offset;
|
|
goto fail;
|
|
}
|
|
|
|
sn->l1_table_offset = l1_table_offset;
|
|
sn->l1_size = s->l1_size;
|
|
|
|
l1_table = g_try_new(uint64_t, s->l1_size);
|
|
if (s->l1_size && l1_table == NULL) {
|
|
ret = -ENOMEM;
|
|
goto fail;
|
|
}
|
|
|
|
for(i = 0; i < s->l1_size; i++) {
|
|
l1_table[i] = cpu_to_be64(s->l1_table[i]);
|
|
}
|
|
|
|
ret = qcow2_pre_write_overlap_check(bs, 0, sn->l1_table_offset,
|
|
s->l1_size * sizeof(uint64_t));
|
|
if (ret < 0) {
|
|
goto fail;
|
|
}
|
|
|
|
ret = bdrv_pwrite(bs->file, sn->l1_table_offset, l1_table,
|
|
s->l1_size * sizeof(uint64_t));
|
|
if (ret < 0) {
|
|
goto fail;
|
|
}
|
|
|
|
g_free(l1_table);
|
|
l1_table = NULL;
|
|
|
|
/*
|
|
* Increase the refcounts of all clusters and make sure everything is
|
|
* stable on disk before updating the snapshot table to contain a pointer
|
|
* to the new L1 table.
|
|
*/
|
|
ret = qcow2_update_snapshot_refcount(bs, s->l1_table_offset, s->l1_size, 1);
|
|
if (ret < 0) {
|
|
goto fail;
|
|
}
|
|
|
|
/* Append the new snapshot to the snapshot list */
|
|
new_snapshot_list = g_new(QCowSnapshot, s->nb_snapshots + 1);
|
|
if (s->snapshots) {
|
|
memcpy(new_snapshot_list, s->snapshots,
|
|
s->nb_snapshots * sizeof(QCowSnapshot));
|
|
old_snapshot_list = s->snapshots;
|
|
}
|
|
s->snapshots = new_snapshot_list;
|
|
s->snapshots[s->nb_snapshots++] = *sn;
|
|
|
|
ret = qcow2_write_snapshots(bs);
|
|
if (ret < 0) {
|
|
g_free(s->snapshots);
|
|
s->snapshots = old_snapshot_list;
|
|
s->nb_snapshots--;
|
|
goto fail;
|
|
}
|
|
|
|
g_free(old_snapshot_list);
|
|
|
|
/* The VM state isn't needed any more in the active L1 table; in fact, it
|
|
* hurts by causing expensive COW for the next snapshot. */
|
|
qcow2_cluster_discard(bs, qcow2_vm_state_offset(s),
|
|
ROUND_UP(sn->vm_state_size, s->cluster_size),
|
|
QCOW2_DISCARD_NEVER, false);
|
|
|
|
#ifdef DEBUG_ALLOC
|
|
{
|
|
BdrvCheckResult result = {0};
|
|
qcow2_check_refcounts(bs, &result, 0);
|
|
}
|
|
#endif
|
|
return 0;
|
|
|
|
fail:
|
|
g_free(sn->id_str);
|
|
g_free(sn->name);
|
|
g_free(l1_table);
|
|
|
|
return ret;
|
|
}
|
|
|
|
/* copy the snapshot 'snapshot_name' into the current disk image */
|
|
int qcow2_snapshot_goto(BlockDriverState *bs, const char *snapshot_id)
|
|
{
|
|
BDRVQcow2State *s = bs->opaque;
|
|
QCowSnapshot *sn;
|
|
int i, snapshot_index;
|
|
int cur_l1_bytes, sn_l1_bytes;
|
|
int ret;
|
|
uint64_t *sn_l1_table = NULL;
|
|
|
|
/* Search the snapshot */
|
|
snapshot_index = find_snapshot_by_id_or_name(bs, snapshot_id);
|
|
if (snapshot_index < 0) {
|
|
return -ENOENT;
|
|
}
|
|
sn = &s->snapshots[snapshot_index];
|
|
|
|
if (sn->disk_size != bs->total_sectors * BDRV_SECTOR_SIZE) {
|
|
error_report("qcow2: Loading snapshots with different disk "
|
|
"size is not implemented");
|
|
ret = -ENOTSUP;
|
|
goto fail;
|
|
}
|
|
|
|
/*
|
|
* Make sure that the current L1 table is big enough to contain the whole
|
|
* L1 table of the snapshot. If the snapshot L1 table is smaller, the
|
|
* current one must be padded with zeros.
|
|
*/
|
|
ret = qcow2_grow_l1_table(bs, sn->l1_size, true);
|
|
if (ret < 0) {
|
|
goto fail;
|
|
}
|
|
|
|
cur_l1_bytes = s->l1_size * sizeof(uint64_t);
|
|
sn_l1_bytes = sn->l1_size * sizeof(uint64_t);
|
|
|
|
/*
|
|
* Copy the snapshot L1 table to the current L1 table.
|
|
*
|
|
* Before overwriting the old current L1 table on disk, make sure to
|
|
* increase all refcounts for the clusters referenced by the new one.
|
|
* Decrease the refcount referenced by the old one only when the L1
|
|
* table is overwritten.
|
|
*/
|
|
sn_l1_table = g_try_malloc0(cur_l1_bytes);
|
|
if (cur_l1_bytes && sn_l1_table == NULL) {
|
|
ret = -ENOMEM;
|
|
goto fail;
|
|
}
|
|
|
|
ret = bdrv_pread(bs->file, sn->l1_table_offset,
|
|
sn_l1_table, sn_l1_bytes);
|
|
if (ret < 0) {
|
|
goto fail;
|
|
}
|
|
|
|
ret = qcow2_update_snapshot_refcount(bs, sn->l1_table_offset,
|
|
sn->l1_size, 1);
|
|
if (ret < 0) {
|
|
goto fail;
|
|
}
|
|
|
|
ret = qcow2_pre_write_overlap_check(bs, QCOW2_OL_ACTIVE_L1,
|
|
s->l1_table_offset, cur_l1_bytes);
|
|
if (ret < 0) {
|
|
goto fail;
|
|
}
|
|
|
|
ret = bdrv_pwrite_sync(bs->file, s->l1_table_offset, sn_l1_table,
|
|
cur_l1_bytes);
|
|
if (ret < 0) {
|
|
goto fail;
|
|
}
|
|
|
|
/*
|
|
* Decrease refcount of clusters of current L1 table.
|
|
*
|
|
* At this point, the in-memory s->l1_table points to the old L1 table,
|
|
* whereas on disk we already have the new one.
|
|
*
|
|
* qcow2_update_snapshot_refcount special cases the current L1 table to use
|
|
* the in-memory data instead of really using the offset to load a new one,
|
|
* which is why this works.
|
|
*/
|
|
ret = qcow2_update_snapshot_refcount(bs, s->l1_table_offset,
|
|
s->l1_size, -1);
|
|
|
|
/*
|
|
* Now update the in-memory L1 table to be in sync with the on-disk one. We
|
|
* need to do this even if updating refcounts failed.
|
|
*/
|
|
for(i = 0;i < s->l1_size; i++) {
|
|
s->l1_table[i] = be64_to_cpu(sn_l1_table[i]);
|
|
}
|
|
|
|
if (ret < 0) {
|
|
goto fail;
|
|
}
|
|
|
|
g_free(sn_l1_table);
|
|
sn_l1_table = NULL;
|
|
|
|
/*
|
|
* Update QCOW_OFLAG_COPIED in the active L1 table (it may have changed
|
|
* when we decreased the refcount of the old snapshot.
|
|
*/
|
|
ret = qcow2_update_snapshot_refcount(bs, s->l1_table_offset, s->l1_size, 0);
|
|
if (ret < 0) {
|
|
goto fail;
|
|
}
|
|
|
|
#ifdef DEBUG_ALLOC
|
|
{
|
|
BdrvCheckResult result = {0};
|
|
qcow2_check_refcounts(bs, &result, 0);
|
|
}
|
|
#endif
|
|
return 0;
|
|
|
|
fail:
|
|
g_free(sn_l1_table);
|
|
return ret;
|
|
}
|
|
|
|
int qcow2_snapshot_delete(BlockDriverState *bs,
|
|
const char *snapshot_id,
|
|
const char *name,
|
|
Error **errp)
|
|
{
|
|
BDRVQcow2State *s = bs->opaque;
|
|
QCowSnapshot sn;
|
|
int snapshot_index, ret;
|
|
|
|
/* Search the snapshot */
|
|
snapshot_index = find_snapshot_by_id_and_name(bs, snapshot_id, name);
|
|
if (snapshot_index < 0) {
|
|
error_setg(errp, "Can't find the snapshot");
|
|
return -ENOENT;
|
|
}
|
|
sn = s->snapshots[snapshot_index];
|
|
|
|
/* Remove it from the snapshot list */
|
|
memmove(s->snapshots + snapshot_index,
|
|
s->snapshots + snapshot_index + 1,
|
|
(s->nb_snapshots - snapshot_index - 1) * sizeof(sn));
|
|
s->nb_snapshots--;
|
|
ret = qcow2_write_snapshots(bs);
|
|
if (ret < 0) {
|
|
error_setg_errno(errp, -ret,
|
|
"Failed to remove snapshot from snapshot list");
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* The snapshot is now unused, clean up. If we fail after this point, we
|
|
* won't recover but just leak clusters.
|
|
*/
|
|
g_free(sn.id_str);
|
|
g_free(sn.name);
|
|
|
|
/*
|
|
* Now decrease the refcounts of clusters referenced by the snapshot and
|
|
* free the L1 table.
|
|
*/
|
|
ret = qcow2_update_snapshot_refcount(bs, sn.l1_table_offset,
|
|
sn.l1_size, -1);
|
|
if (ret < 0) {
|
|
error_setg_errno(errp, -ret, "Failed to free the cluster and L1 table");
|
|
return ret;
|
|
}
|
|
qcow2_free_clusters(bs, sn.l1_table_offset, sn.l1_size * sizeof(uint64_t),
|
|
QCOW2_DISCARD_SNAPSHOT);
|
|
|
|
/* must update the copied flag on the current cluster offsets */
|
|
ret = qcow2_update_snapshot_refcount(bs, s->l1_table_offset, s->l1_size, 0);
|
|
if (ret < 0) {
|
|
error_setg_errno(errp, -ret,
|
|
"Failed to update snapshot status in disk");
|
|
return ret;
|
|
}
|
|
|
|
#ifdef DEBUG_ALLOC
|
|
{
|
|
BdrvCheckResult result = {0};
|
|
qcow2_check_refcounts(bs, &result, 0);
|
|
}
|
|
#endif
|
|
return 0;
|
|
}
|
|
|
|
int qcow2_snapshot_list(BlockDriverState *bs, QEMUSnapshotInfo **psn_tab)
|
|
{
|
|
BDRVQcow2State *s = bs->opaque;
|
|
QEMUSnapshotInfo *sn_tab, *sn_info;
|
|
QCowSnapshot *sn;
|
|
int i;
|
|
|
|
if (!s->nb_snapshots) {
|
|
*psn_tab = NULL;
|
|
return s->nb_snapshots;
|
|
}
|
|
|
|
sn_tab = g_new0(QEMUSnapshotInfo, s->nb_snapshots);
|
|
for(i = 0; i < s->nb_snapshots; i++) {
|
|
sn_info = sn_tab + i;
|
|
sn = s->snapshots + i;
|
|
pstrcpy(sn_info->id_str, sizeof(sn_info->id_str),
|
|
sn->id_str);
|
|
pstrcpy(sn_info->name, sizeof(sn_info->name),
|
|
sn->name);
|
|
sn_info->vm_state_size = sn->vm_state_size;
|
|
sn_info->date_sec = sn->date_sec;
|
|
sn_info->date_nsec = sn->date_nsec;
|
|
sn_info->vm_clock_nsec = sn->vm_clock_nsec;
|
|
}
|
|
*psn_tab = sn_tab;
|
|
return s->nb_snapshots;
|
|
}
|
|
|
|
int qcow2_snapshot_load_tmp(BlockDriverState *bs,
|
|
const char *snapshot_id,
|
|
const char *name,
|
|
Error **errp)
|
|
{
|
|
int i, snapshot_index;
|
|
BDRVQcow2State *s = bs->opaque;
|
|
QCowSnapshot *sn;
|
|
uint64_t *new_l1_table;
|
|
int new_l1_bytes;
|
|
int ret;
|
|
|
|
assert(bs->read_only);
|
|
|
|
/* Search the snapshot */
|
|
snapshot_index = find_snapshot_by_id_and_name(bs, snapshot_id, name);
|
|
if (snapshot_index < 0) {
|
|
error_setg(errp,
|
|
"Can't find snapshot");
|
|
return -ENOENT;
|
|
}
|
|
sn = &s->snapshots[snapshot_index];
|
|
|
|
/* Allocate and read in the snapshot's L1 table */
|
|
if (sn->l1_size > QCOW_MAX_L1_SIZE / sizeof(uint64_t)) {
|
|
error_setg(errp, "Snapshot L1 table too large");
|
|
return -EFBIG;
|
|
}
|
|
new_l1_bytes = sn->l1_size * sizeof(uint64_t);
|
|
new_l1_table = qemu_try_blockalign(bs->file->bs,
|
|
ROUND_UP(new_l1_bytes, 512));
|
|
if (new_l1_table == NULL) {
|
|
return -ENOMEM;
|
|
}
|
|
|
|
ret = bdrv_pread(bs->file, sn->l1_table_offset,
|
|
new_l1_table, new_l1_bytes);
|
|
if (ret < 0) {
|
|
error_setg(errp, "Failed to read l1 table for snapshot");
|
|
qemu_vfree(new_l1_table);
|
|
return ret;
|
|
}
|
|
|
|
/* Switch the L1 table */
|
|
qemu_vfree(s->l1_table);
|
|
|
|
s->l1_size = sn->l1_size;
|
|
s->l1_table_offset = sn->l1_table_offset;
|
|
s->l1_table = new_l1_table;
|
|
|
|
for(i = 0;i < s->l1_size; i++) {
|
|
be64_to_cpus(&s->l1_table[i]);
|
|
}
|
|
|
|
return 0;
|
|
}
|