From: edison <edi...@cloud.com>
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.
Signed-off-by: Disheng Su <edi...@cloud.com>
---
block.c | 11 +++++++++++
block.h | 2 ++
block/qcow2-snapshot.c | 26 ++++++++++++++++++++++++++
block/qcow2.c | 1 +
block/qcow2.h | 1 +
block_int.h | 2 ++
qemu-img-cmds.hx | 4 ++--
qemu-img.c | 19 ++++++++++++++++++-
8 files changed, 63 insertions(+), 3 deletions(-)
diff --git a/block.c b/block.c
index ebbc376..eaf78f6 100644
--- a/block.c
+++ b/block.c
@@ -1899,6 +1899,17 @@ int bdrv_snapshot_list(BlockDriverState *bs,
return -ENOTSUP;
}
+int bdrv_snapshot_load(BlockDriverState *bs,
+ const char *snapshot_name)
+{
+ BlockDriver *drv = bs->drv;
+ if (!drv)
+ return -ENOMEDIUM;
+ if (drv->bdrv_snapshot_load)
+ return drv->bdrv_snapshot_load(bs, snapshot_name);
+ return -ENOTSUP;
+}
+
#define NB_SUFFIXES 4
char *get_human_readable_size(char *buf, int buf_size, int64_t size)
diff --git a/block.h b/block.h
index 5f64380..9ec6219 100644
--- a/block.h
+++ b/block.h
@@ -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(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);
diff --git a/block/qcow2-snapshot.c b/block/qcow2-snapshot.c
index 6228612..e663e8b 100644
--- a/block/qcow2-snapshot.c
+++ b/block/qcow2-snapshot.c
@@ -416,3 +416,29 @@ int qcow2_snapshot_list(BlockDriverState *bs,
QEMUSnapshotInfo **psn_tab)
return s->nb_snapshots;
}
+int qcow2_snapshot_load(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));
+ /* 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) {
+ return -1;
+ }
+ for(i = 0;i < s->l1_size; i++) {
+ be64_to_cpus(&s->l1_table[i]);
+ }
+ return 0;
+}
diff --git a/block/qcow2.c b/block/qcow2.c
index a53014d..da98a01 100644
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -1352,6 +1352,7 @@ 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 = qcow2_snapshot_load,
.bdrv_get_info = qcow_get_info,
.bdrv_save_vmstate = qcow_save_vmstate,
diff --git a/block/qcow2.h b/block/qcow2.h
index 3ff162e..cbbba48 100644
--- a/block/qcow2.h
+++ b/block/qcow2.h
@@ -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(BlockDriverState *bs, const char *snapshot_name);
void qcow2_free_snapshots(BlockDriverState *bs);
int qcow2_read_snapshots(BlockDriverState *bs);
diff --git a/block_int.h b/block_int.h
index e8e7156..93d5a1b 100644
--- a/block_int.h
+++ b/block_int.h
@@ -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)(BlockDriverState *bs,
+ const char *snapshot_name);
int (*bdrv_get_info)(BlockDriverState *bs, BlockDriverInfo *bdi);
int (*bdrv_save_vmstate)(BlockDriverState *bs, const uint8_t *buf,
diff --git a/qemu-img-cmds.hx b/qemu-img-cmds.hx
index 6d3e5f8..6c7176f 100644
--- a/qemu-img-cmds.hx
+++ b/qemu-img-cmds.hx
@@ -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,
diff --git a/qemu-img.c b/qemu-img.c
index 4e035e4..7ff015d 100644
--- a/qemu-img.c
+++ b/qemu-img.c
@@ -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(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) {
--
1.7.2.2
