raw_open() expects the caller always passing in the right actual @options parameter. But when trying to applying snapshot on a RBD image, bdrv_snapshot_goto() calls raw_open() (by calling the bdrv_open callback on the BlockDriver) with a NULL @options, and that will result in a Segmentation fault. For the other non-raw format drivers, it also makes sense to passing in the actual options, althought they don't trigger the problem so far. Let's prepare a @options by adding the "file" key-value pair to a copy of the actual options that were given for the node (i.e. bs->options), and pass it to the callback. BlockDriver.bdrv_open() expects bs->file to be NULL and just overwrites it with the result from bdrv_open_child(). That means we should actually make sure it's NULL because otherwise the child BDS will have a reference count that is 1 too high. So we unconditionally invoke bdrv_unref_child() before calling BlockDriver.bdrv_open(), and we wrap everything in bdrv_ref()/bdrv_unref() so the BDS isn't deleted in the meantime. Suggested-by: Max Reitz <mreitz@redhat.com> Signed-off-by: Dong Jia Shi <bjsdjshi@linux.vnet.ibm.com> Message-id: 20170405091909.36357-2-bjsdjshi@linux.vnet.ibm.com Signed-off-by: Max Reitz <mreitz@redhat.com>
542 lines
15 KiB
C
542 lines
15 KiB
C
/*
|
|
* Block layer snapshot related functions
|
|
*
|
|
* Copyright (c) 2003-2008 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 "block/snapshot.h"
|
|
#include "block/block_int.h"
|
|
#include "qapi/error.h"
|
|
#include "qapi/qmp/qerror.h"
|
|
#include "qapi/qmp/qstring.h"
|
|
|
|
QemuOptsList internal_snapshot_opts = {
|
|
.name = "snapshot",
|
|
.head = QTAILQ_HEAD_INITIALIZER(internal_snapshot_opts.head),
|
|
.desc = {
|
|
{
|
|
.name = SNAPSHOT_OPT_ID,
|
|
.type = QEMU_OPT_STRING,
|
|
.help = "snapshot id"
|
|
},{
|
|
.name = SNAPSHOT_OPT_NAME,
|
|
.type = QEMU_OPT_STRING,
|
|
.help = "snapshot name"
|
|
},{
|
|
/* end of list */
|
|
}
|
|
},
|
|
};
|
|
|
|
int bdrv_snapshot_find(BlockDriverState *bs, QEMUSnapshotInfo *sn_info,
|
|
const char *name)
|
|
{
|
|
QEMUSnapshotInfo *sn_tab, *sn;
|
|
int nb_sns, i, ret;
|
|
|
|
ret = -ENOENT;
|
|
nb_sns = bdrv_snapshot_list(bs, &sn_tab);
|
|
if (nb_sns < 0) {
|
|
return ret;
|
|
}
|
|
for (i = 0; i < nb_sns; i++) {
|
|
sn = &sn_tab[i];
|
|
if (!strcmp(sn->id_str, name) || !strcmp(sn->name, name)) {
|
|
*sn_info = *sn;
|
|
ret = 0;
|
|
break;
|
|
}
|
|
}
|
|
g_free(sn_tab);
|
|
return ret;
|
|
}
|
|
|
|
/**
|
|
* Look up an internal snapshot by @id and @name.
|
|
* @bs: block device to search
|
|
* @id: unique snapshot ID, or NULL
|
|
* @name: snapshot name, or NULL
|
|
* @sn_info: location to store information on the snapshot found
|
|
* @errp: location to store error, will be set only for exception
|
|
*
|
|
* This function will traverse snapshot list in @bs to search the matching
|
|
* one, @id and @name are the matching condition:
|
|
* If both @id and @name are specified, find the first one with id @id and
|
|
* name @name.
|
|
* If only @id is specified, find the first one with id @id.
|
|
* If only @name is specified, find the first one with name @name.
|
|
* if none is specified, abort().
|
|
*
|
|
* Returns: true when a snapshot is found and @sn_info will be filled, false
|
|
* when error or not found. If all operation succeed but no matching one is
|
|
* found, @errp will NOT be set.
|
|
*/
|
|
bool bdrv_snapshot_find_by_id_and_name(BlockDriverState *bs,
|
|
const char *id,
|
|
const char *name,
|
|
QEMUSnapshotInfo *sn_info,
|
|
Error **errp)
|
|
{
|
|
QEMUSnapshotInfo *sn_tab, *sn;
|
|
int nb_sns, i;
|
|
bool ret = false;
|
|
|
|
assert(id || name);
|
|
|
|
nb_sns = bdrv_snapshot_list(bs, &sn_tab);
|
|
if (nb_sns < 0) {
|
|
error_setg_errno(errp, -nb_sns, "Failed to get a snapshot list");
|
|
return false;
|
|
} else if (nb_sns == 0) {
|
|
return false;
|
|
}
|
|
|
|
if (id && name) {
|
|
for (i = 0; i < nb_sns; i++) {
|
|
sn = &sn_tab[i];
|
|
if (!strcmp(sn->id_str, id) && !strcmp(sn->name, name)) {
|
|
*sn_info = *sn;
|
|
ret = true;
|
|
break;
|
|
}
|
|
}
|
|
} else if (id) {
|
|
for (i = 0; i < nb_sns; i++) {
|
|
sn = &sn_tab[i];
|
|
if (!strcmp(sn->id_str, id)) {
|
|
*sn_info = *sn;
|
|
ret = true;
|
|
break;
|
|
}
|
|
}
|
|
} else if (name) {
|
|
for (i = 0; i < nb_sns; i++) {
|
|
sn = &sn_tab[i];
|
|
if (!strcmp(sn->name, name)) {
|
|
*sn_info = *sn;
|
|
ret = true;
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
|
|
g_free(sn_tab);
|
|
return ret;
|
|
}
|
|
|
|
int bdrv_can_snapshot(BlockDriverState *bs)
|
|
{
|
|
BlockDriver *drv = bs->drv;
|
|
if (!drv || !bdrv_is_inserted(bs) || bdrv_is_read_only(bs)) {
|
|
return 0;
|
|
}
|
|
|
|
if (!drv->bdrv_snapshot_create) {
|
|
if (bs->file != NULL) {
|
|
return bdrv_can_snapshot(bs->file->bs);
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
return 1;
|
|
}
|
|
|
|
int bdrv_snapshot_create(BlockDriverState *bs,
|
|
QEMUSnapshotInfo *sn_info)
|
|
{
|
|
BlockDriver *drv = bs->drv;
|
|
if (!drv) {
|
|
return -ENOMEDIUM;
|
|
}
|
|
if (drv->bdrv_snapshot_create) {
|
|
return drv->bdrv_snapshot_create(bs, sn_info);
|
|
}
|
|
if (bs->file) {
|
|
return bdrv_snapshot_create(bs->file->bs, sn_info);
|
|
}
|
|
return -ENOTSUP;
|
|
}
|
|
|
|
int bdrv_snapshot_goto(BlockDriverState *bs,
|
|
const char *snapshot_id)
|
|
{
|
|
BlockDriver *drv = bs->drv;
|
|
int ret, open_ret;
|
|
|
|
if (!drv) {
|
|
return -ENOMEDIUM;
|
|
}
|
|
if (drv->bdrv_snapshot_goto) {
|
|
return drv->bdrv_snapshot_goto(bs, snapshot_id);
|
|
}
|
|
|
|
if (bs->file) {
|
|
BlockDriverState *file;
|
|
QDict *options = qdict_clone_shallow(bs->options);
|
|
QDict *file_options;
|
|
|
|
file = bs->file->bs;
|
|
/* Prevent it from getting deleted when detached from bs */
|
|
bdrv_ref(file);
|
|
|
|
qdict_extract_subqdict(options, &file_options, "file.");
|
|
QDECREF(file_options);
|
|
qdict_put(options, "file", qstring_from_str(bdrv_get_node_name(file)));
|
|
|
|
drv->bdrv_close(bs);
|
|
bdrv_unref_child(bs, bs->file);
|
|
bs->file = NULL;
|
|
|
|
ret = bdrv_snapshot_goto(file, snapshot_id);
|
|
open_ret = drv->bdrv_open(bs, options, bs->open_flags, NULL);
|
|
QDECREF(options);
|
|
if (open_ret < 0) {
|
|
bdrv_unref(file);
|
|
bs->drv = NULL;
|
|
return open_ret;
|
|
}
|
|
|
|
assert(bs->file->bs == file);
|
|
bdrv_unref(file);
|
|
return ret;
|
|
}
|
|
|
|
return -ENOTSUP;
|
|
}
|
|
|
|
/**
|
|
* Delete an internal snapshot by @snapshot_id and @name.
|
|
* @bs: block device used in the operation
|
|
* @snapshot_id: unique snapshot ID, or NULL
|
|
* @name: snapshot name, or NULL
|
|
* @errp: location to store error
|
|
*
|
|
* If both @snapshot_id and @name are specified, delete the first one with
|
|
* id @snapshot_id and name @name.
|
|
* If only @snapshot_id is specified, delete the first one with id
|
|
* @snapshot_id.
|
|
* If only @name is specified, delete the first one with name @name.
|
|
* if none is specified, return -EINVAL.
|
|
*
|
|
* Returns: 0 on success, -errno on failure. If @bs is not inserted, return
|
|
* -ENOMEDIUM. If @snapshot_id and @name are both NULL, return -EINVAL. If @bs
|
|
* does not support internal snapshot deletion, return -ENOTSUP. If @bs does
|
|
* not support parameter @snapshot_id or @name, or one of them is not correctly
|
|
* specified, return -EINVAL. If @bs can't find one matching @id and @name,
|
|
* return -ENOENT. If @errp != NULL, it will always be filled with error
|
|
* message on failure.
|
|
*/
|
|
int bdrv_snapshot_delete(BlockDriverState *bs,
|
|
const char *snapshot_id,
|
|
const char *name,
|
|
Error **errp)
|
|
{
|
|
BlockDriver *drv = bs->drv;
|
|
int ret;
|
|
|
|
if (!drv) {
|
|
error_setg(errp, QERR_DEVICE_HAS_NO_MEDIUM, bdrv_get_device_name(bs));
|
|
return -ENOMEDIUM;
|
|
}
|
|
if (!snapshot_id && !name) {
|
|
error_setg(errp, "snapshot_id and name are both NULL");
|
|
return -EINVAL;
|
|
}
|
|
|
|
/* drain all pending i/o before deleting snapshot */
|
|
bdrv_drained_begin(bs);
|
|
|
|
if (drv->bdrv_snapshot_delete) {
|
|
ret = drv->bdrv_snapshot_delete(bs, snapshot_id, name, errp);
|
|
} else if (bs->file) {
|
|
ret = bdrv_snapshot_delete(bs->file->bs, snapshot_id, name, errp);
|
|
} else {
|
|
error_setg(errp, "Block format '%s' used by device '%s' "
|
|
"does not support internal snapshot deletion",
|
|
drv->format_name, bdrv_get_device_name(bs));
|
|
ret = -ENOTSUP;
|
|
}
|
|
|
|
bdrv_drained_end(bs);
|
|
return ret;
|
|
}
|
|
|
|
int bdrv_snapshot_delete_by_id_or_name(BlockDriverState *bs,
|
|
const char *id_or_name,
|
|
Error **errp)
|
|
{
|
|
int ret;
|
|
Error *local_err = NULL;
|
|
|
|
ret = bdrv_snapshot_delete(bs, id_or_name, NULL, &local_err);
|
|
if (ret == -ENOENT || ret == -EINVAL) {
|
|
error_free(local_err);
|
|
local_err = NULL;
|
|
ret = bdrv_snapshot_delete(bs, NULL, id_or_name, &local_err);
|
|
}
|
|
|
|
if (ret < 0) {
|
|
error_propagate(errp, local_err);
|
|
}
|
|
return ret;
|
|
}
|
|
|
|
int bdrv_snapshot_list(BlockDriverState *bs,
|
|
QEMUSnapshotInfo **psn_info)
|
|
{
|
|
BlockDriver *drv = bs->drv;
|
|
if (!drv) {
|
|
return -ENOMEDIUM;
|
|
}
|
|
if (drv->bdrv_snapshot_list) {
|
|
return drv->bdrv_snapshot_list(bs, psn_info);
|
|
}
|
|
if (bs->file) {
|
|
return bdrv_snapshot_list(bs->file->bs, psn_info);
|
|
}
|
|
return -ENOTSUP;
|
|
}
|
|
|
|
/**
|
|
* Temporarily load an internal snapshot by @snapshot_id and @name.
|
|
* @bs: block device used in the operation
|
|
* @snapshot_id: unique snapshot ID, or NULL
|
|
* @name: snapshot name, or NULL
|
|
* @errp: location to store error
|
|
*
|
|
* If both @snapshot_id and @name are specified, load the first one with
|
|
* id @snapshot_id and name @name.
|
|
* If only @snapshot_id is specified, load the first one with id
|
|
* @snapshot_id.
|
|
* If only @name is specified, load the first one with name @name.
|
|
* if none is specified, return -EINVAL.
|
|
*
|
|
* Returns: 0 on success, -errno on fail. If @bs is not inserted, return
|
|
* -ENOMEDIUM. If @bs is not readonly, return -EINVAL. If @bs did not support
|
|
* internal snapshot, return -ENOTSUP. If qemu can't find a matching @id and
|
|
* @name, return -ENOENT. If @errp != NULL, it will always be filled on
|
|
* failure.
|
|
*/
|
|
int bdrv_snapshot_load_tmp(BlockDriverState *bs,
|
|
const char *snapshot_id,
|
|
const char *name,
|
|
Error **errp)
|
|
{
|
|
BlockDriver *drv = bs->drv;
|
|
|
|
if (!drv) {
|
|
error_setg(errp, QERR_DEVICE_HAS_NO_MEDIUM, bdrv_get_device_name(bs));
|
|
return -ENOMEDIUM;
|
|
}
|
|
if (!snapshot_id && !name) {
|
|
error_setg(errp, "snapshot_id and name are both NULL");
|
|
return -EINVAL;
|
|
}
|
|
if (!bs->read_only) {
|
|
error_setg(errp, "Device is not readonly");
|
|
return -EINVAL;
|
|
}
|
|
if (drv->bdrv_snapshot_load_tmp) {
|
|
return drv->bdrv_snapshot_load_tmp(bs, snapshot_id, name, errp);
|
|
}
|
|
error_setg(errp, "Block format '%s' used by device '%s' "
|
|
"does not support temporarily loading internal snapshots",
|
|
drv->format_name, bdrv_get_device_name(bs));
|
|
return -ENOTSUP;
|
|
}
|
|
|
|
int bdrv_snapshot_load_tmp_by_id_or_name(BlockDriverState *bs,
|
|
const char *id_or_name,
|
|
Error **errp)
|
|
{
|
|
int ret;
|
|
Error *local_err = NULL;
|
|
|
|
ret = bdrv_snapshot_load_tmp(bs, id_or_name, NULL, &local_err);
|
|
if (ret == -ENOENT || ret == -EINVAL) {
|
|
error_free(local_err);
|
|
local_err = NULL;
|
|
ret = bdrv_snapshot_load_tmp(bs, NULL, id_or_name, &local_err);
|
|
}
|
|
|
|
error_propagate(errp, local_err);
|
|
|
|
return ret;
|
|
}
|
|
|
|
|
|
/* Group operations. All block drivers are involved.
|
|
* These functions will properly handle dataplane (take aio_context_acquire
|
|
* when appropriate for appropriate block drivers) */
|
|
|
|
bool bdrv_all_can_snapshot(BlockDriverState **first_bad_bs)
|
|
{
|
|
bool ok = true;
|
|
BlockDriverState *bs;
|
|
BdrvNextIterator it;
|
|
|
|
for (bs = bdrv_first(&it); bs; bs = bdrv_next(&it)) {
|
|
AioContext *ctx = bdrv_get_aio_context(bs);
|
|
|
|
aio_context_acquire(ctx);
|
|
if (bdrv_is_inserted(bs) && !bdrv_is_read_only(bs)) {
|
|
ok = bdrv_can_snapshot(bs);
|
|
}
|
|
aio_context_release(ctx);
|
|
if (!ok) {
|
|
goto fail;
|
|
}
|
|
}
|
|
|
|
fail:
|
|
*first_bad_bs = bs;
|
|
return ok;
|
|
}
|
|
|
|
int bdrv_all_delete_snapshot(const char *name, BlockDriverState **first_bad_bs,
|
|
Error **err)
|
|
{
|
|
int ret = 0;
|
|
BlockDriverState *bs;
|
|
BdrvNextIterator it;
|
|
QEMUSnapshotInfo sn1, *snapshot = &sn1;
|
|
|
|
for (bs = bdrv_first(&it); bs; bs = bdrv_next(&it)) {
|
|
AioContext *ctx = bdrv_get_aio_context(bs);
|
|
|
|
aio_context_acquire(ctx);
|
|
if (bdrv_can_snapshot(bs) &&
|
|
bdrv_snapshot_find(bs, snapshot, name) >= 0) {
|
|
ret = bdrv_snapshot_delete_by_id_or_name(bs, name, err);
|
|
}
|
|
aio_context_release(ctx);
|
|
if (ret < 0) {
|
|
goto fail;
|
|
}
|
|
}
|
|
|
|
fail:
|
|
*first_bad_bs = bs;
|
|
return ret;
|
|
}
|
|
|
|
|
|
int bdrv_all_goto_snapshot(const char *name, BlockDriverState **first_bad_bs)
|
|
{
|
|
int err = 0;
|
|
BlockDriverState *bs;
|
|
BdrvNextIterator it;
|
|
|
|
for (bs = bdrv_first(&it); bs; bs = bdrv_next(&it)) {
|
|
AioContext *ctx = bdrv_get_aio_context(bs);
|
|
|
|
aio_context_acquire(ctx);
|
|
if (bdrv_can_snapshot(bs)) {
|
|
err = bdrv_snapshot_goto(bs, name);
|
|
}
|
|
aio_context_release(ctx);
|
|
if (err < 0) {
|
|
goto fail;
|
|
}
|
|
}
|
|
|
|
fail:
|
|
*first_bad_bs = bs;
|
|
return err;
|
|
}
|
|
|
|
int bdrv_all_find_snapshot(const char *name, BlockDriverState **first_bad_bs)
|
|
{
|
|
QEMUSnapshotInfo sn;
|
|
int err = 0;
|
|
BlockDriverState *bs;
|
|
BdrvNextIterator it;
|
|
|
|
for (bs = bdrv_first(&it); bs; bs = bdrv_next(&it)) {
|
|
AioContext *ctx = bdrv_get_aio_context(bs);
|
|
|
|
aio_context_acquire(ctx);
|
|
if (bdrv_can_snapshot(bs)) {
|
|
err = bdrv_snapshot_find(bs, &sn, name);
|
|
}
|
|
aio_context_release(ctx);
|
|
if (err < 0) {
|
|
goto fail;
|
|
}
|
|
}
|
|
|
|
fail:
|
|
*first_bad_bs = bs;
|
|
return err;
|
|
}
|
|
|
|
int bdrv_all_create_snapshot(QEMUSnapshotInfo *sn,
|
|
BlockDriverState *vm_state_bs,
|
|
uint64_t vm_state_size,
|
|
BlockDriverState **first_bad_bs)
|
|
{
|
|
int err = 0;
|
|
BlockDriverState *bs;
|
|
BdrvNextIterator it;
|
|
|
|
for (bs = bdrv_first(&it); bs; bs = bdrv_next(&it)) {
|
|
AioContext *ctx = bdrv_get_aio_context(bs);
|
|
|
|
aio_context_acquire(ctx);
|
|
if (bs == vm_state_bs) {
|
|
sn->vm_state_size = vm_state_size;
|
|
err = bdrv_snapshot_create(bs, sn);
|
|
} else if (bdrv_can_snapshot(bs)) {
|
|
sn->vm_state_size = 0;
|
|
err = bdrv_snapshot_create(bs, sn);
|
|
}
|
|
aio_context_release(ctx);
|
|
if (err < 0) {
|
|
goto fail;
|
|
}
|
|
}
|
|
|
|
fail:
|
|
*first_bad_bs = bs;
|
|
return err;
|
|
}
|
|
|
|
BlockDriverState *bdrv_all_find_vmstate_bs(void)
|
|
{
|
|
BlockDriverState *bs;
|
|
BdrvNextIterator it;
|
|
|
|
for (bs = bdrv_first(&it); bs; bs = bdrv_next(&it)) {
|
|
AioContext *ctx = bdrv_get_aio_context(bs);
|
|
bool found;
|
|
|
|
aio_context_acquire(ctx);
|
|
found = bdrv_can_snapshot(bs);
|
|
aio_context_release(ctx);
|
|
|
|
if (found) {
|
|
break;
|
|
}
|
|
}
|
|
return bs;
|
|
}
|