Commit e83dd680 authored by Kevin Wolf's avatar Kevin Wolf
Browse files

mirror: Make sure that source and target size match 



If the target is shorter than the source, mirror would copy data until
it reaches the end of the target and then fail with an I/O error when
trying to write past the end.

If the target is longer than the source, the mirror job would complete
successfully, but the target wouldn't actually be an accurate copy of
the source image (it would contain some additional garbage at the end).

Fix this by checking that both images have the same size when the job
starts.

Signed-off-by: default avatarKevin Wolf <kwolf@redhat.com>
Reviewed-by: default avatarEric Blake <eblake@redhat.com>
Message-Id: <20200511135825.219437-4-kwolf@redhat.com>
Reviewed-by: default avatarMax Reitz <mreitz@redhat.com>
Reviewed-by: default avatarVladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Signed-off-by: default avatarKevin Wolf <kwolf@redhat.com>
parent d89ac3cf

block/mirror.c

+12 −9
Original line number Diff line number Diff line
@@ -872,6 +872,7 @@ static int coroutine_fn mirror_run(Job *job, Error **errp) 
    BlockDriverState *target_bs = blk_bs(s->target);

    bool need_drain = true;

    int64_t length;

    int64_t target_length;

    BlockDriverInfo bdi;

    char backing_filename[2]; /* we only need 2 characters because we are only

                                 checking for a NULL string */
@@ -887,24 +888,26 @@ static int coroutine_fn mirror_run(Job *job, Error **errp) 
        goto immediate_exit;

    }



    /* Active commit must resize the base image if its size differs from the

     * active layer. */

    if (s->base == blk_bs(s->target)) {

        int64_t base_length;



        base_length = blk_getlength(s->target);

        if (base_length < 0) {

            ret = base_length;

    target_length = blk_getlength(s->target);

    if (target_length < 0) {

        ret = target_length;

        goto immediate_exit;

    }



        if (s->bdev_length > base_length) {

    /* Active commit must resize the base image if its size differs from the

     * active layer. */

    if (s->base == blk_bs(s->target)) {

        if (s->bdev_length > target_length) {

            ret = blk_truncate(s->target, s->bdev_length, false,

                               PREALLOC_MODE_OFF, 0, NULL);

            if (ret < 0) {

                goto immediate_exit;

            }

        }

    } else if (s->bdev_length != target_length) {

        error_setg(errp, "Source and target image have different sizes");

        ret = -EINVAL;

        goto immediate_exit;

    }



    if (s->bdev_length == 0) {