mirror of
https://github.com/qemu/qemu.git
synced 2024-12-11 12:43:55 +08:00
8b3b720620
Use bdrv_(p)write_sync to ensure metadata integrity in case of a crash. Signed-off-by: Kevin Wolf <kwolf@redhat.com>
419 lines
12 KiB
C
419 lines
12 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-common.h"
|
|
#include "block_int.h"
|
|
#include "block/qcow2.h"
|
|
|
|
typedef struct __attribute__((packed)) QCowSnapshotHeader {
|
|
/* header is 8 byte aligned */
|
|
uint64_t l1_table_offset;
|
|
|
|
uint32_t l1_size;
|
|
uint16_t id_str_size;
|
|
uint16_t name_size;
|
|
|
|
uint32_t date_sec;
|
|
uint32_t date_nsec;
|
|
|
|
uint64_t vm_clock_nsec;
|
|
|
|
uint32_t vm_state_size;
|
|
uint32_t extra_data_size; /* for extension */
|
|
/* extra data follows */
|
|
/* id_str follows */
|
|
/* name follows */
|
|
} QCowSnapshotHeader;
|
|
|
|
void qcow2_free_snapshots(BlockDriverState *bs)
|
|
{
|
|
BDRVQcowState *s = bs->opaque;
|
|
int i;
|
|
|
|
for(i = 0; i < s->nb_snapshots; i++) {
|
|
qemu_free(s->snapshots[i].name);
|
|
qemu_free(s->snapshots[i].id_str);
|
|
}
|
|
qemu_free(s->snapshots);
|
|
s->snapshots = NULL;
|
|
s->nb_snapshots = 0;
|
|
}
|
|
|
|
int qcow2_read_snapshots(BlockDriverState *bs)
|
|
{
|
|
BDRVQcowState *s = bs->opaque;
|
|
QCowSnapshotHeader h;
|
|
QCowSnapshot *sn;
|
|
int i, id_str_size, name_size;
|
|
int64_t offset;
|
|
uint32_t extra_data_size;
|
|
|
|
if (!s->nb_snapshots) {
|
|
s->snapshots = NULL;
|
|
s->snapshots_size = 0;
|
|
return 0;
|
|
}
|
|
|
|
offset = s->snapshots_offset;
|
|
s->snapshots = qemu_mallocz(s->nb_snapshots * sizeof(QCowSnapshot));
|
|
for(i = 0; i < s->nb_snapshots; i++) {
|
|
offset = align_offset(offset, 8);
|
|
if (bdrv_pread(bs->file, offset, &h, sizeof(h)) != sizeof(h))
|
|
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);
|
|
|
|
offset += extra_data_size;
|
|
|
|
sn->id_str = qemu_malloc(id_str_size + 1);
|
|
if (bdrv_pread(bs->file, offset, sn->id_str, id_str_size) != id_str_size)
|
|
goto fail;
|
|
offset += id_str_size;
|
|
sn->id_str[id_str_size] = '\0';
|
|
|
|
sn->name = qemu_malloc(name_size + 1);
|
|
if (bdrv_pread(bs->file, offset, sn->name, name_size) != name_size)
|
|
goto fail;
|
|
offset += name_size;
|
|
sn->name[name_size] = '\0';
|
|
}
|
|
s->snapshots_size = offset - s->snapshots_offset;
|
|
return 0;
|
|
fail:
|
|
qcow2_free_snapshots(bs);
|
|
return -1;
|
|
}
|
|
|
|
/* add at the end of the file a new list of snapshots */
|
|
static int qcow_write_snapshots(BlockDriverState *bs)
|
|
{
|
|
BDRVQcowState *s = bs->opaque;
|
|
QCowSnapshot *sn;
|
|
QCowSnapshotHeader h;
|
|
int i, name_size, id_str_size, snapshots_size;
|
|
uint64_t data64;
|
|
uint32_t data32;
|
|
int64_t offset, snapshots_offset;
|
|
|
|
/* compute the size of the snapshots */
|
|
offset = 0;
|
|
for(i = 0; i < s->nb_snapshots; i++) {
|
|
sn = s->snapshots + i;
|
|
offset = align_offset(offset, 8);
|
|
offset += sizeof(h);
|
|
offset += strlen(sn->id_str);
|
|
offset += strlen(sn->name);
|
|
}
|
|
snapshots_size = offset;
|
|
|
|
snapshots_offset = qcow2_alloc_clusters(bs, snapshots_size);
|
|
offset = snapshots_offset;
|
|
if (offset < 0) {
|
|
return offset;
|
|
}
|
|
|
|
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);
|
|
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);
|
|
|
|
id_str_size = strlen(sn->id_str);
|
|
name_size = strlen(sn->name);
|
|
h.id_str_size = cpu_to_be16(id_str_size);
|
|
h.name_size = cpu_to_be16(name_size);
|
|
offset = align_offset(offset, 8);
|
|
if (bdrv_pwrite_sync(bs->file, offset, &h, sizeof(h)) < 0)
|
|
goto fail;
|
|
offset += sizeof(h);
|
|
if (bdrv_pwrite_sync(bs->file, offset, sn->id_str, id_str_size) < 0)
|
|
goto fail;
|
|
offset += id_str_size;
|
|
if (bdrv_pwrite_sync(bs->file, offset, sn->name, name_size) < 0)
|
|
goto fail;
|
|
offset += name_size;
|
|
}
|
|
|
|
/* update the various header fields */
|
|
data64 = cpu_to_be64(snapshots_offset);
|
|
if (bdrv_pwrite_sync(bs->file, offsetof(QCowHeader, snapshots_offset),
|
|
&data64, sizeof(data64)) < 0)
|
|
goto fail;
|
|
data32 = cpu_to_be32(s->nb_snapshots);
|
|
if (bdrv_pwrite_sync(bs->file, offsetof(QCowHeader, nb_snapshots),
|
|
&data32, sizeof(data32)) < 0)
|
|
goto fail;
|
|
|
|
/* free the old snapshot table */
|
|
qcow2_free_clusters(bs, s->snapshots_offset, s->snapshots_size);
|
|
s->snapshots_offset = snapshots_offset;
|
|
s->snapshots_size = snapshots_size;
|
|
return 0;
|
|
fail:
|
|
return -1;
|
|
}
|
|
|
|
static void find_new_snapshot_id(BlockDriverState *bs,
|
|
char *id_str, int id_str_size)
|
|
{
|
|
BDRVQcowState *s = bs->opaque;
|
|
QCowSnapshot *sn;
|
|
int i, 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, "%d", id_max + 1);
|
|
}
|
|
|
|
static int find_snapshot_by_id(BlockDriverState *bs, const char *id_str)
|
|
{
|
|
BDRVQcowState *s = bs->opaque;
|
|
int i;
|
|
|
|
for(i = 0; i < s->nb_snapshots; i++) {
|
|
if (!strcmp(s->snapshots[i].id_str, id_str))
|
|
return i;
|
|
}
|
|
return -1;
|
|
}
|
|
|
|
static int find_snapshot_by_id_or_name(BlockDriverState *bs, const char *name)
|
|
{
|
|
BDRVQcowState *s = bs->opaque;
|
|
int i, ret;
|
|
|
|
ret = find_snapshot_by_id(bs, name);
|
|
if (ret >= 0)
|
|
return ret;
|
|
for(i = 0; i < s->nb_snapshots; i++) {
|
|
if (!strcmp(s->snapshots[i].name, name))
|
|
return i;
|
|
}
|
|
return -1;
|
|
}
|
|
|
|
/* if no id is provided, a new one is constructed */
|
|
int qcow2_snapshot_create(BlockDriverState *bs, QEMUSnapshotInfo *sn_info)
|
|
{
|
|
BDRVQcowState *s = bs->opaque;
|
|
QCowSnapshot *snapshots1, sn1, *sn = &sn1;
|
|
int i, ret;
|
|
uint64_t *l1_table = NULL;
|
|
int64_t l1_table_offset;
|
|
|
|
memset(sn, 0, sizeof(*sn));
|
|
|
|
if (sn_info->id_str[0] == '\0') {
|
|
/* compute a new 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(bs, sn_info->id_str) >= 0)
|
|
return -ENOENT;
|
|
|
|
sn->id_str = qemu_strdup(sn_info->id_str);
|
|
if (!sn->id_str)
|
|
goto fail;
|
|
sn->name = qemu_strdup(sn_info->name);
|
|
if (!sn->name)
|
|
goto fail;
|
|
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;
|
|
|
|
ret = qcow2_update_snapshot_refcount(bs, s->l1_table_offset, s->l1_size, 1);
|
|
if (ret < 0)
|
|
goto fail;
|
|
|
|
/* create the L1 table of the snapshot */
|
|
l1_table_offset = qcow2_alloc_clusters(bs, s->l1_size * sizeof(uint64_t));
|
|
if (l1_table_offset < 0) {
|
|
goto fail;
|
|
}
|
|
|
|
sn->l1_table_offset = l1_table_offset;
|
|
sn->l1_size = s->l1_size;
|
|
|
|
if (s->l1_size != 0) {
|
|
l1_table = qemu_malloc(s->l1_size * sizeof(uint64_t));
|
|
} else {
|
|
l1_table = NULL;
|
|
}
|
|
|
|
for(i = 0; i < s->l1_size; i++) {
|
|
l1_table[i] = cpu_to_be64(s->l1_table[i]);
|
|
}
|
|
if (bdrv_pwrite_sync(bs->file, sn->l1_table_offset,
|
|
l1_table, s->l1_size * sizeof(uint64_t)) < 0)
|
|
goto fail;
|
|
qemu_free(l1_table);
|
|
l1_table = NULL;
|
|
|
|
snapshots1 = qemu_malloc((s->nb_snapshots + 1) * sizeof(QCowSnapshot));
|
|
if (s->snapshots) {
|
|
memcpy(snapshots1, s->snapshots, s->nb_snapshots * sizeof(QCowSnapshot));
|
|
qemu_free(s->snapshots);
|
|
}
|
|
s->snapshots = snapshots1;
|
|
s->snapshots[s->nb_snapshots++] = *sn;
|
|
|
|
if (qcow_write_snapshots(bs) < 0)
|
|
goto fail;
|
|
#ifdef DEBUG_ALLOC
|
|
qcow2_check_refcounts(bs);
|
|
#endif
|
|
return 0;
|
|
fail:
|
|
qemu_free(sn->name);
|
|
qemu_free(l1_table);
|
|
return -1;
|
|
}
|
|
|
|
/* copy the snapshot 'snapshot_name' into the current disk image */
|
|
int qcow2_snapshot_goto(BlockDriverState *bs, const char *snapshot_id)
|
|
{
|
|
BDRVQcowState *s = bs->opaque;
|
|
QCowSnapshot *sn;
|
|
int i, snapshot_index, l1_size2;
|
|
|
|
snapshot_index = find_snapshot_by_id_or_name(bs, snapshot_id);
|
|
if (snapshot_index < 0)
|
|
return -ENOENT;
|
|
sn = &s->snapshots[snapshot_index];
|
|
|
|
if (qcow2_update_snapshot_refcount(bs, s->l1_table_offset, s->l1_size, -1) < 0)
|
|
goto fail;
|
|
|
|
if (qcow2_grow_l1_table(bs, sn->l1_size) < 0)
|
|
goto fail;
|
|
|
|
s->l1_size = sn->l1_size;
|
|
l1_size2 = s->l1_size * sizeof(uint64_t);
|
|
/* copy the snapshot l1 table to the current l1 table */
|
|
if (bdrv_pread(bs->file, sn->l1_table_offset,
|
|
s->l1_table, l1_size2) != l1_size2)
|
|
goto fail;
|
|
if (bdrv_pwrite_sync(bs->file, s->l1_table_offset,
|
|
s->l1_table, l1_size2) < 0)
|
|
goto fail;
|
|
for(i = 0;i < s->l1_size; i++) {
|
|
be64_to_cpus(&s->l1_table[i]);
|
|
}
|
|
|
|
if (qcow2_update_snapshot_refcount(bs, s->l1_table_offset, s->l1_size, 1) < 0)
|
|
goto fail;
|
|
|
|
#ifdef DEBUG_ALLOC
|
|
qcow2_check_refcounts(bs);
|
|
#endif
|
|
return 0;
|
|
fail:
|
|
return -EIO;
|
|
}
|
|
|
|
int qcow2_snapshot_delete(BlockDriverState *bs, const char *snapshot_id)
|
|
{
|
|
BDRVQcowState *s = bs->opaque;
|
|
QCowSnapshot *sn;
|
|
int snapshot_index, ret;
|
|
|
|
snapshot_index = find_snapshot_by_id_or_name(bs, snapshot_id);
|
|
if (snapshot_index < 0)
|
|
return -ENOENT;
|
|
sn = &s->snapshots[snapshot_index];
|
|
|
|
ret = qcow2_update_snapshot_refcount(bs, sn->l1_table_offset, sn->l1_size, -1);
|
|
if (ret < 0)
|
|
return ret;
|
|
/* 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)
|
|
return ret;
|
|
qcow2_free_clusters(bs, sn->l1_table_offset, sn->l1_size * sizeof(uint64_t));
|
|
|
|
qemu_free(sn->id_str);
|
|
qemu_free(sn->name);
|
|
memmove(sn, sn + 1, (s->nb_snapshots - snapshot_index - 1) * sizeof(*sn));
|
|
s->nb_snapshots--;
|
|
ret = qcow_write_snapshots(bs);
|
|
if (ret < 0) {
|
|
/* XXX: restore snapshot if error ? */
|
|
return ret;
|
|
}
|
|
#ifdef DEBUG_ALLOC
|
|
qcow2_check_refcounts(bs);
|
|
#endif
|
|
return 0;
|
|
}
|
|
|
|
int qcow2_snapshot_list(BlockDriverState *bs, QEMUSnapshotInfo **psn_tab)
|
|
{
|
|
BDRVQcowState *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 = qemu_mallocz(s->nb_snapshots * sizeof(QEMUSnapshotInfo));
|
|
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;
|
|
}
|
|
|