Commit 15e39ad9 authored by Eric Blake's avatar Eric Blake
Browse files

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: default avatarEric Blake <eblake@redhat.com>
Message-Id: <20200521192137.1120211-5-eblake@redhat.com>
Reviewed-by: default avatarVladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
parent 6c729dd8

docs/tools/qemu-img.rst

+5 −1
Original line number Diff line number Diff line
@@ -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

qemu-img-cmds.hx

+2 −2
Original line number Diff line number Diff line
@@ -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,

qemu-img.c

+67 −3
Original line number Diff line number Diff line
@@ -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);