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qemu-img: Add convert --bitmaps option 

Make it easier to copy all the persistent bitmaps of (the top layer
of) a source image along with its guest-visible contents, by adding a
boolean flag for use with qemu-img convert.  This is basically
shorthand, as the same effect could be accomplished with a series of
'qemu-img bitmap --add' and 'qemu-img bitmap --merge -b source'
commands, or by their corresponding QMP commands.

Note that this command will fail in the same scenarios where 'qemu-img
measure' omits a 'bitmaps size:' line, namely, when either the source
or the destination lacks persistent bitmap support altogether.

See also https://bugzilla.redhat.com/show_bug.cgi?id=1779893

While touching this, clean up a couple coding issues spotted in the
same function: an extra blank line, and merging back-to-back 'if
(!skip_create)' blocks.

Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <20200521192137.1120211-5-eblake@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
This commit is contained in:
Eric Blake 2020-05-21 14:21:36 -05:00
parent 6c729dd832
commit 15e39ad950
3 changed files with 74 additions and 6 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

6
docs/tools/qemu-img.rst
View File

@ -162,6 +162,10 @@ Parameters to convert subcommand:
.. program:: qemu-img-convert
.. option:: --bitmaps
Additionally copy all persistent bitmaps from the top layer of the source
.. option:: -n
Skip the creation of the target volume
@ -397,7 +401,7 @@ Command description:
4
Error on reading data
.. option:: convert [--object OBJECTDEF] [--image-opts] [--target-image-opts] [--target-is-zero] [-U] [-C] [-c] [-p] [-q] [-n] [-f FMT] [-t CACHE] [-T SRC_CACHE] [-O OUTPUT_FMT] [-B BACKING_FILE] [-o OPTIONS] [-l SNAPSHOT_PARAM] [-S SPARSE_SIZE] [-m NUM_COROUTINES] [-W] FILENAME [FILENAME2 [...]] OUTPUT_FILENAME
.. option:: convert [--object OBJECTDEF] [--image-opts] [--target-image-opts] [--target-is-zero] [--bitmaps] [-U] [-C] [-c] [-p] [-q] [-n] [-f FMT] [-t CACHE] [-T SRC_CACHE] [-O OUTPUT_FMT] [-B BACKING_FILE] [-o OPTIONS] [-l SNAPSHOT_PARAM] [-S SPARSE_SIZE] [-m NUM_COROUTINES] [-W] FILENAME [FILENAME2 [...]] OUTPUT_FILENAME
Convert the disk image *FILENAME* or a snapshot *SNAPSHOT_PARAM*
to disk image *OUTPUT_FILENAME* using format *OUTPUT_FMT*. It can

4
qemu-img-cmds.hx
View File

@ -46,9 +46,9 @@ SRST
ERST
DEF("convert", img_convert,
"convert [--object objectdef] [--image-opts] [--target-image-opts] [--target-is-zero] [-U] [-C] [-c] [-p] [-q] [-n] [-f fmt] [-t cache] [-T src_cache] [-O output_fmt] [-B backing_file] [-o options] [-l snapshot_param] [-S sparse_size] [-m num_coroutines] [-W] [--salvage] filename [filename2 [...]] output_filename")
"convert [--object objectdef] [--image-opts] [--target-image-opts] [--target-is-zero] [--bitmaps] [-U] [-C] [-c] [-p] [-q] [-n] [-f fmt] [-t cache] [-T src_cache] [-O output_fmt] [-B backing_file] [-o options] [-l snapshot_param] [-S sparse_size] [-m num_coroutines] [-W] [--salvage] filename [filename2 [...]] output_filename")
SRST
.. option:: convert [--object OBJECTDEF] [--image-opts] [--target-image-opts] [--target-is-zero] [-U] [-C] [-c] [-p] [-q] [-n] [-f FMT] [-t CACHE] [-T SRC_CACHE] [-O OUTPUT_FMT] [-B BACKING_FILE] [-o OPTIONS] [-l SNAPSHOT_PARAM] [-S SPARSE_SIZE] [-m NUM_COROUTINES] [-W] [--salvage] FILENAME [FILENAME2 [...]] OUTPUT_FILENAME
.. option:: convert [--object OBJECTDEF] [--image-opts] [--target-image-opts] [--target-is-zero] [--bitmaps] [-U] [-C] [-c] [-p] [-q] [-n] [-f FMT] [-t CACHE] [-T SRC_CACHE] [-O OUTPUT_FMT] [-B BACKING_FILE] [-o OPTIONS] [-l SNAPSHOT_PARAM] [-S SPARSE_SIZE] [-m NUM_COROUTINES] [-W] [--salvage] FILENAME [FILENAME2 [...]] OUTPUT_FILENAME
ERST
DEF("create", img_create,

70
qemu-img.c
View File

@ -78,6 +78,7 @@ enum {
OPTION_ENABLE = 272,
OPTION_DISABLE = 273,
OPTION_MERGE = 274,
OPTION_BITMAPS = 275,
};
typedef enum OutputFormat {
@ -191,6 +192,7 @@ static void QEMU_NORETURN help(void)
" hiding corruption that has already occurred.\n"
"\n"
"Parameters to convert subcommand:\n"
" '--bitmaps' copies all top-level persistent bitmaps to destination\n"
" '-m' specifies how many coroutines work in parallel during the convert\n"
" process (defaults to 8)\n"
" '-W' allow to write to the target out of order rather than sequential\n"
@ -2139,6 +2141,39 @@ static int convert_do_copy(ImgConvertState *s)
return s->ret;
}
static int convert_copy_bitmaps(BlockDriverState *src, BlockDriverState *dst)
{
BdrvDirtyBitmap *bm;
Error *err = NULL;
FOR_EACH_DIRTY_BITMAP(src, bm) {
const char *name;
if (!bdrv_dirty_bitmap_get_persistence(bm)) {
continue;
}
name = bdrv_dirty_bitmap_name(bm);
qmp_block_dirty_bitmap_add(dst->node_name, name,
true, bdrv_dirty_bitmap_granularity(bm),
true, true,
true, !bdrv_dirty_bitmap_enabled(bm),
&err);
if (err) {
error_reportf_err(err, "Failed to create bitmap %s: ", name);
return -1;
}
do_dirty_bitmap_merge(dst->node_name, name, src->node_name, name,
&err);
if (err) {
error_reportf_err(err, "Failed to populate bitmap %s: ", name);
return -1;
}
}
return 0;
}
#define MAX_BUF_SECTORS 32768
static int img_convert(int argc, char **argv)
@ -2160,6 +2195,7 @@ static int img_convert(int argc, char **argv)
int64_t ret = -EINVAL;
bool force_share = false;
bool explict_min_sparse = false;
bool bitmaps = false;
ImgConvertState s = (ImgConvertState) {
/* Need at least 4k of zeros for sparse detection */
@ -2179,6 +2215,7 @@ static int img_convert(int argc, char **argv)
{"target-image-opts", no_argument, 0, OPTION_TARGET_IMAGE_OPTS},
{"salvage", no_argument, 0, OPTION_SALVAGE},
{"target-is-zero", no_argument, 0, OPTION_TARGET_IS_ZERO},
{"bitmaps", no_argument, 0, OPTION_BITMAPS},
{0, 0, 0, 0}
};
c = getopt_long(argc, argv, ":hf:O:B:Cco:l:S:pt:T:qnm:WU",
@ -2304,6 +2341,9 @@ static int img_convert(int argc, char **argv)
*/
s.has_zero_init = true;
break;
case OPTION_BITMAPS:
bitmaps = true;
break;
}
}
@ -2365,7 +2405,6 @@ static int img_convert(int argc, char **argv)
goto fail_getopt;
}
/* ret is still -EINVAL until here */
ret = bdrv_parse_cache_mode(src_cache, &src_flags, &src_writethrough);
if (ret < 0) {
@ -2525,6 +2564,20 @@ static int img_convert(int argc, char **argv)
}
}
/* Determine if bitmaps need copying */
if (bitmaps) {
if (s.src_num > 1) {
error_report("Copying bitmaps only possible with single source");
ret = -1;
goto out;
}
if (!bdrv_supports_persistent_dirty_bitmap(blk_bs(s.src[0]))) {
error_report("Source lacks bitmap support");
ret = -1;
goto out;
}
}
/*
* The later open call will need any decryption secrets, and
* bdrv_create() will purge "opts", so extract them now before
@ -2533,9 +2586,7 @@ static int img_convert(int argc, char **argv)
if (!skip_create) {
open_opts = qdict_new();
qemu_opt_foreach(opts, img_add_key_secrets, open_opts, &error_abort);
}
if (!skip_create) {
/* Create the new image */
ret = bdrv_create(drv, out_filename, opts, &local_err);
if (ret < 0) {
@ -2573,6 +2624,13 @@ static int img_convert(int argc, char **argv)
}
out_bs = blk_bs(s.target);
if (bitmaps && !bdrv_supports_persistent_dirty_bitmap(out_bs)) {
error_report("Format driver '%s' does not support bitmaps",
out_bs->drv->format_name);
ret = -1;
goto out;
}
if (s.compressed && !block_driver_can_compress(out_bs->drv)) {
error_report("Compression not supported for this file format");
ret = -1;
@ -2632,6 +2690,12 @@ static int img_convert(int argc, char **argv)
}
ret = convert_do_copy(&s);
/* Now copy the bitmaps */
if (bitmaps && ret == 0) {
ret = convert_copy_bitmaps(blk_bs(s.src[0]), out_bs);
}
out:
if (!ret) {
qemu_progress_print(100, 0);