Commit 51ef6727 authored by edison's avatar edison Committed by Kevin Wolf

Copy snapshots out of QCOW2 disk

In order to backup snapshots, created from QCOW2 iamge, we want to copy snapshots out of QCOW2 disk to a seperate storage.
The following patch adds a new option in "qemu-img": qemu-img convert -f qcow2 -O qcow2 -s snapshot_name src_img bck_img.
Right now, it only supports to copy the full snapshot, delta snapshot is on the way.

Changes from V1: all the comments from Kevin are addressed:
Add read-only checking
Fix coding style
Change the name from bdrv_snapshot_load to bdrv_snapshot_load_tmp
Signed-off-by: default avatarDisheng Su <edison@cloud.com>
Signed-off-by: default avatarKevin Wolf <kwolf@redhat.com>
parent a58b8d54
......@@ -1899,6 +1899,22 @@ int bdrv_snapshot_list(BlockDriverState *bs,
return -ENOTSUP;
}
int bdrv_snapshot_load_tmp(BlockDriverState *bs,
const char *snapshot_name)
{
BlockDriver *drv = bs->drv;
if (!drv) {
return -ENOMEDIUM;
}
if (!bs->read_only) {
return -EINVAL;
}
if (drv->bdrv_snapshot_load_tmp) {
return drv->bdrv_snapshot_load_tmp(bs, snapshot_name);
}
return -ENOTSUP;
}
#define NB_SUFFIXES 4
char *get_human_readable_size(char *buf, int buf_size, int64_t size)
......
......@@ -211,6 +211,8 @@ int bdrv_snapshot_goto(BlockDriverState *bs,
int bdrv_snapshot_delete(BlockDriverState *bs, const char *snapshot_id);
int bdrv_snapshot_list(BlockDriverState *bs,
QEMUSnapshotInfo **psn_info);
int bdrv_snapshot_load_tmp(BlockDriverState *bs,
const char *snapshot_name);
char *bdrv_snapshot_dump(char *buf, int buf_size, QEMUSnapshotInfo *sn);
char *get_human_readable_size(char *buf, int buf_size, int64_t size);
......
......@@ -418,3 +418,34 @@ int qcow2_snapshot_list(BlockDriverState *bs, QEMUSnapshotInfo **psn_tab)
return s->nb_snapshots;
}
int qcow2_snapshot_load_tmp(BlockDriverState *bs, const char *snapshot_name)
{
int i, snapshot_index, l1_size2;
BDRVQcowState *s = bs->opaque;
QCowSnapshot *sn;
snapshot_index = find_snapshot_by_id_or_name(bs, snapshot_name);
if (snapshot_index < 0) {
return -ENOENT;
}
sn = &s->snapshots[snapshot_index];
s->l1_size = sn->l1_size;
l1_size2 = s->l1_size * sizeof(uint64_t);
if (s->l1_table != NULL) {
qemu_free(s->l1_table);
}
s->l1_table_offset = sn->l1_table_offset;
s->l1_table = qemu_mallocz(align_offset(l1_size2, 512));
if (bdrv_pread(bs->file, sn->l1_table_offset,
s->l1_table, l1_size2) != l1_size2) {
return -1;
}
for(i = 0;i < s->l1_size; i++) {
be64_to_cpus(&s->l1_table[i]);
}
return 0;
}
......@@ -1286,6 +1286,7 @@ static BlockDriver bdrv_qcow2 = {
.bdrv_snapshot_goto = qcow2_snapshot_goto,
.bdrv_snapshot_delete = qcow2_snapshot_delete,
.bdrv_snapshot_list = qcow2_snapshot_list,
.bdrv_snapshot_load_tmp = qcow2_snapshot_load_tmp,
.bdrv_get_info = qcow_get_info,
.bdrv_save_vmstate = qcow_save_vmstate,
......
......@@ -211,6 +211,7 @@ int qcow2_snapshot_create(BlockDriverState *bs, QEMUSnapshotInfo *sn_info);
int qcow2_snapshot_goto(BlockDriverState *bs, const char *snapshot_id);
int qcow2_snapshot_delete(BlockDriverState *bs, const char *snapshot_id);
int qcow2_snapshot_list(BlockDriverState *bs, QEMUSnapshotInfo **psn_tab);
int qcow2_snapshot_load_tmp(BlockDriverState *bs, const char *snapshot_name);
void qcow2_free_snapshots(BlockDriverState *bs);
int qcow2_read_snapshots(BlockDriverState *bs);
......
......@@ -93,6 +93,8 @@ struct BlockDriver {
int (*bdrv_snapshot_delete)(BlockDriverState *bs, const char *snapshot_id);
int (*bdrv_snapshot_list)(BlockDriverState *bs,
QEMUSnapshotInfo **psn_info);
int (*bdrv_snapshot_load_tmp)(BlockDriverState *bs,
const char *snapshot_name);
int (*bdrv_get_info)(BlockDriverState *bs, BlockDriverInfo *bdi);
int (*bdrv_save_vmstate)(BlockDriverState *bs, const uint8_t *buf,
......
......@@ -28,9 +28,9 @@ STEXI
ETEXI
DEF("convert", img_convert,
"convert [-c] [-f fmt] [-O output_fmt] [-o options] filename [filename2 [...]] output_filename")
"convert [-c] [-f fmt] [-O output_fmt] [-o options] [-s snapshot_name] filename [filename2 [...]] output_filename")
STEXI
@item convert [-c] [-f @var{fmt}] [-O @var{output_fmt}] [-o @var{options}] @var{filename} [@var{filename2} [...]] @var{output_filename}
@item convert [-c] [-f @var{fmt}] [-O @var{output_fmt}] [-o @var{options}] [-s @var{snapshot_name}] @var{filename} [@var{filename2} [...]] @var{output_filename}
ETEXI
DEF("info", img_info,
......
......@@ -646,13 +646,14 @@ static int img_convert(int argc, char **argv)
BlockDriverInfo bdi;
QEMUOptionParameter *param = NULL, *create_options = NULL;
char *options = NULL;
const char *snapshot_name = NULL;
fmt = NULL;
out_fmt = "raw";
out_baseimg = NULL;
flags = 0;
for(;;) {
c = getopt(argc, argv, "f:O:B:hce6o:");
c = getopt(argc, argv, "f:O:B:s:hce6o:");
if (c == -1)
break;
switch(c) {
......@@ -680,6 +681,9 @@ static int img_convert(int argc, char **argv)
case 'o':
options = optarg;
break;
case 's':
snapshot_name = optarg;
break;
}
}
......@@ -711,6 +715,19 @@ static int img_convert(int argc, char **argv)
total_sectors += bs_sectors;
}
if (snapshot_name != NULL) {
if (bs_n > 1) {
error("No support for concatenating multiple snapshot\n");
ret = -1;
goto out;
}
if (bdrv_snapshot_load_tmp(bs[0], snapshot_name) < 0) {
error("Failed to load snapshot\n");
ret = -1;
goto out;
}
}
/* Find driver and parse its options */
drv = bdrv_find_format(out_fmt);
if (!drv) {
......
......@@ -77,9 +77,9 @@ it doesn't need to be specified separately in this case.
Commit the changes recorded in @var{filename} in its base image.
@item convert [-c] [-f @var{fmt}] [-O @var{output_fmt}] [-o @var{options}] @var{filename} [@var{filename2} [...]] @var{output_filename}
@item convert [-c] [-f @var{fmt}] [-O @var{output_fmt}] [-o @var{options}] [-s @var{snapshot_name}] @var{filename} [@var{filename2} [...]] @var{output_filename}
Convert the disk image @var{filename} to disk image @var{output_filename}
Convert the disk image @var{filename} or a snapshot @var{snapshot_name} to disk image @var{output_filename}
using format @var{output_fmt}. It can be optionally compressed (@code{-c}
option) or use any format specific options like encryption (@code{-o} option).
......
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