On Wed, 07/03 16:34, Paolo Bonzini wrote:
> This command dumps the metadata of an entire chain, in either tabular or JSON
> format.
>
> Signed-off-by: Paolo Bonzini <pbonz...@redhat.com>
> ---
> qemu-img-cmds.hx | 6 ++
> qemu-img.c | 186
> +++++++++++++++++++++++++++++++++++++++++++++++++++++++
> 2 files changed, 192 insertions(+)
>
> diff --git a/qemu-img-cmds.hx b/qemu-img-cmds.hx
> index 4ca7e95..acc3a1c 100644
> --- a/qemu-img-cmds.hx
> +++ b/qemu-img-cmds.hx
> @@ -45,6 +45,12 @@ STEXI
> @item info [-f @var{fmt}] [--output=@var{ofmt}] [--backing-chain]
> @var{filename}
> ETEXI
>
> +DEF("map", img_map,
> + "map [-f fmt] [--output=ofmt] filename")
> +STEXI
> +@item map [-f @var{fmt}] [--output=@var{ofmt}] filename
> +ETEXI
> +
> DEF("snapshot", img_snapshot,
> "snapshot [-q] [-l | -a snapshot | -c snapshot | -d snapshot] filename")
> STEXI
> diff --git a/qemu-img.c b/qemu-img.c
> index 6461932..97392a5 100644
> --- a/qemu-img.c
> +++ b/qemu-img.c
> @@ -1768,6 +1768,192 @@ static int img_info(int argc, char **argv)
> return 0;
> }
>
> +
> +typedef struct MapEntry {
> + int flags;
> + int depth;
> + int64_t start;
> + int64_t length;
> + int64_t offset;
> +} MapEntry;
> +
> +static void dump_map_entry(OutputFormat output_format, MapEntry *e,
> + MapEntry *next)
> +{
> + switch (output_format) {
> + case OFORMAT_HUMAN:
> + if ((e->flags & (BDRV_BLOCK_DATA|BDRV_BLOCK_ZERO)) ==
> BDRV_BLOCK_DATA) {
> + printf("%lld %lld %d %lld\n",
> + (long long) e->start, (long long) e->length,
> + e->depth, (long long) e->offset);
> + }
Why %lld and explicit cast, not using PRId64?
Is BDRV_BLOCK_DATA and BDRV_BLOCK_ZERO distinguishable here for the
user? By offset?
> + /* This format ignores the distinction between 0, ZERO and ZERO|DATA.
> + * Modify the flags here to allow more coalescing.
> + */
> + if (next &&
> + (next->flags & (BDRV_BLOCK_DATA|BDRV_BLOCK_ZERO)) !=
> BDRV_BLOCK_DATA) {
> + next->flags &= ~BDRV_BLOCK_DATA;
> + next->flags |= BDRV_BLOCK_ZERO;
> + }
> + break;
> + case OFORMAT_JSON:
> + printf("%s{ 'depth': %d, 'start': %lld, 'length': %lld, "
> + "'zero': %s, 'data': %s",
> + (e->start == 0 ? "[" : ",\n"),
> + e->depth, (long long) e->start, (long long) e->length,
> + (e->flags & BDRV_BLOCK_ZERO) ? "true" : "false",
> + (e->flags & BDRV_BLOCK_DATA) ? "true" : "false");
> + if (e->flags & BDRV_BLOCK_OFFSET_VALID) {
> + printf(", 'offset': %lld", (long long) e->offset);
> + }
> + putchar('}');
No indentation.
> +
> + if (!next) {
> + printf("]\n");
> + }
> + break;
> + }
> +}
> +
> +static int64_t get_block_status(BlockDriverState *bs, int64_t sector_num,
> + int *nb_sectors, int *depth)
> +{
> + int64_t ret;
> +
> + /* As an optimization, we could cache the current range of unallocated
> + * clusters in each file of the chain, and avoid querying the same
> + * range repeatedly.
> + */
> +
> + *depth = 0;
> + for (;;) {
> + int orig_nb_sectors = *nb_sectors;
> +
> + if (bs == NULL) {
> + return 0;
> + }
> + ret = bdrv_get_block_status(bs, sector_num, *nb_sectors, nb_sectors);
> + if (ret < 0) {
> + return ret;
> + }
> +
> + if (ret & (BDRV_BLOCK_ZERO|BDRV_BLOCK_DATA)) {
> + return ret;
> + }
> + if (!*nb_sectors) {
> + /* Beyond the end of this image (while presumably within the
> + * range of the BlockDriverState above this one). The extra
> + * data is read as zeroes.
> + */
> + *nb_sectors = orig_nb_sectors;
> + return BDRV_BLOCK_ZERO;
> + }
> +
> + bs = bs->backing_hd;
> + (*depth)++;
> + }
> +}
> +
> +static int img_map(int argc, char **argv)
> +{
> + int c;
> + OutputFormat output_format = OFORMAT_HUMAN;
> + BlockDriverState *bs;
> + const char *filename, *fmt, *output;
> + int64_t length;
> + MapEntry curr = { .length = 0 }, next;
> +
> + fmt = NULL;
> + output = NULL;
> + for(;;) {
> + int option_index = 0;
> + static const struct option long_options[] = {
> + {"help", no_argument, 0, 'h'},
> + {"format", required_argument, 0, 'f'},
> + {"output", required_argument, 0, OPTION_OUTPUT},
> + {0, 0, 0, 0}
> + };
> + c = getopt_long(argc, argv, "f:h",
> + long_options, &option_index);
> + if (c == -1) {
> + break;
> + }
> + switch(c) {
> + case '?':
> + case 'h':
> + help();
> + break;
> + case 'f':
> + fmt = optarg;
> + break;
> + case OPTION_OUTPUT:
> + output = optarg;
> + break;
> + }
> + }
> + if (optind >= argc) {
> + help();
> + }
> + filename = argv[optind++];
> +
> + if (output && !strcmp(output, "json")) {
> + output_format = OFORMAT_JSON;
> + } else if (output && !strcmp(output, "human")) {
> + output_format = OFORMAT_HUMAN;
> + } else if (output) {
> + error_report("--output must be used with human or json as
> argument.");
> + return 1;
> + }
> +
> + bs = bdrv_new_open(filename, fmt, BDRV_O_FLAGS, true, false);
> + if (!bs) {
> + return 1;
> + }
> +
> + length = bdrv_getlength(bs);
> + while (curr.start + curr.length < length) {
> + int64_t nsectors_left, ret;
> + int64_t sector_num;
> + int n, depth, flags;
> +
> + /* Probe up to 1 G at a time. */
> + sector_num = (curr.start + curr.length) >> BDRV_SECTOR_BITS;
> + nsectors_left = DIV_ROUND_UP(length, BDRV_SECTOR_SIZE) - sector_num;
> + n = MAX(1 << (30 - BDRV_SECTOR_BITS), nsectors_left);
It's MAX or MIN?
> + ret = get_block_status(bs, sector_num, &n, &depth);
> +
> + if (ret < 0) {
> + error_report("Could not read file metadata: %s", strerror(-ret));
> + return 1;
> + }
> + if ((ret & BDRV_BLOCK_DATA) &&
> + !(ret & BDRV_BLOCK_OFFSET_VALID)) {
> + error_report("File contains external or compressed clusters.");
> + return 1;
> + }
> +
> + flags = ret & ~BDRV_BLOCK_OFFSET_MASK;
> + ret &= BDRV_BLOCK_OFFSET_MASK;
> + if (curr.length == 0 || curr.flags != flags || curr.depth != depth ||
> + ((curr.flags & BDRV_BLOCK_OFFSET_VALID) &&
> + curr.offset + curr.length != ret)) {
A hard tab here.
> + next.flags = flags;
> + next.depth = depth;
> + next.start = sector_num << BDRV_SECTOR_BITS;
> + next.offset = ret;
> + next.length = 0;
> + if (curr.length > 0) {
> + dump_map_entry(output_format, &curr, &next);
> + }
> + curr = next;
> + }
> + curr.length += n << BDRV_SECTOR_BITS;
> + }
> +
> + dump_map_entry(output_format, &curr, NULL);
> + return 0;
> +}
> +
> #define SNAPSHOT_LIST 1
> #define SNAPSHOT_CREATE 2
> #define SNAPSHOT_APPLY 3
> --
> 1.8.2.1
>
>
>
--
Fam
