qemu-block
[Top][All Lists]
Advanced

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [PATCH v5 4/5] qemu-img: Add convert --bitmaps option


From: Nir Soffer
Subject: Re: [PATCH v5 4/5] qemu-img: Add convert --bitmaps option
Date: Thu, 21 May 2020 18:11:07 +0300

On Thu, May 21, 2020 at 1:01 AM Eric Blake <address@hidden> wrote:
>
> 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 QMP commands.
>
> Note that this command will fail in the same scenarios where 'qemu-img
> measure --bitmaps' fails, when either the source or the destanation
> lacks persistent bitmap support altogether.

If we remove --bitmaps option from qemu-img measure, we need to remove
this note.

>
> 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 <address@hidden>
> Message-Id: <address@hidden>
> ---
>  docs/tools/qemu-img.rst |  6 +++-
>  qemu-img.c              | 77 +++++++++++++++++++++++++++++++++++++++--
>  qemu-img-cmds.hx        |  4 +--
>  3 files changed, 81 insertions(+), 6 deletions(-)
>
> diff --git a/docs/tools/qemu-img.rst b/docs/tools/qemu-img.rst
> index 9a8112fc9f58..35050fc51070 100644
> --- a/docs/tools/qemu-img.rst
> +++ b/docs/tools/qemu-img.rst
> @@ -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
> diff --git a/qemu-img.c b/qemu-img.c
> index c1bafb57023a..1494d8f5c409 100644
> --- a/qemu-img.c
> +++ b/qemu-img.c
> @@ -192,6 +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 +2140,39 @@ 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 +2194,8 @@ static int img_convert(int argc, char **argv)
>      int64_t ret = -EINVAL;
>      bool force_share = false;
>      bool explict_min_sparse = false;
> +    bool bitmaps = false;
> +    size_t nbitmaps = 0;
>
>      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 +2564,27 @@ static int img_convert(int argc, char **argv)
>          }
>      }
>
> +    /* Determine how many bitmaps need copying */
> +    if (bitmaps) {
> +        BdrvDirtyBitmap *bm;
> +
> +        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;
> +        }
> +        FOR_EACH_DIRTY_BITMAP(blk_bs(s.src[0]), bm) {
> +            if (bdrv_dirty_bitmap_get_persistence(bm)) {
> +                nbitmaps++;
> +            }
> +        }
> +    }
> +
>      /*
>       * The later open call will need any decryption secrets, and
>       * bdrv_create() will purge "opts", so extract them now before
> @@ -2533,9 +2593,7 @@ 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 +2631,13 @@ static int img_convert(int argc, char **argv)
>      }
>      out_bs = blk_bs(s.target);
>
> +    if (nbitmaps > 0 && !bdrv_supports_persistent_dirty_bitmap(out_bs)) {
> +        error_report("Format driver '%s' does not support bitmaps",
> +                     out_fmt);
> +        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 +2697,12 @@ static int img_convert(int argc, char **argv)
>      }
>
>      ret = convert_do_copy(&s);
> +
> +    /* Now copy the bitmaps */
> +    if (nbitmaps > 0 && ret == 0) {
> +        ret = convert_copy_bitmaps(blk_bs(s.src[0]), out_bs);
> +    }
> +
>  out:
>      if (!ret) {
>          qemu_progress_print(100, 0);
> diff --git a/qemu-img-cmds.hx b/qemu-img-cmds.hx
> index 235cc5fffadc..e9beb15e614e 100644
> --- a/qemu-img-cmds.hx
> +++ b/qemu-img-cmds.hx
> @@ -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,
> --
> 2.26.2
>




reply via email to

[Prev in Thread] Current Thread [Next in Thread]