Commit ae6b12fa authored by Vladimir Sementsov-Ogievskiy's avatar Vladimir Sementsov-Ogievskiy Committed by Max Reitz
Browse files

block/backup: refactor: split out backup_calculate_cluster_size 



Split out cluster_size calculation. Move copy-bitmap creation above
block-job creation, as we are going to share it with upcoming
backup-top filter, which also should be created before actual block job
creation.

Signed-off-by: default avatarVladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-id: 20190429090842.57910-6-vsementsov@virtuozzo.com
[mreitz: Dropped a paragraph from the commit message that was left over
         from a previous version]
Signed-off-by: default avatarMax Reitz <mreitz@redhat.com>
parent c334e897

block/backup.c

+52 −30
Original line number Diff line number Diff line
@@ -497,6 +497,42 @@ static const BlockJobDriver backup_job_driver = { 
    .drain                  = backup_drain,

};



static int64_t backup_calculate_cluster_size(BlockDriverState *target,

                                             Error **errp)

{

    int ret;

    BlockDriverInfo bdi;



    /*

     * If there is no backing file on the target, we cannot rely on COW if our

     * backup cluster size is smaller than the target cluster size. Even for

     * targets with a backing file, try to avoid COW if possible.

     */

    ret = bdrv_get_info(target, &bdi);

    if (ret == -ENOTSUP && !target->backing) {

        /* Cluster size is not defined */

        warn_report("The target block device doesn't provide "

                    "information about the block size and it doesn't have a "

                    "backing file. The default block size of %u bytes is "

                    "used. If the actual block size of the target exceeds "

                    "this default, the backup may be unusable",

                    BACKUP_CLUSTER_SIZE_DEFAULT);

        return BACKUP_CLUSTER_SIZE_DEFAULT;

    } else if (ret < 0 && !target->backing) {

        error_setg_errno(errp, -ret,

            "Couldn't determine the cluster size of the target image, "

            "which has no backing file");

        error_append_hint(errp,

            "Aborting, since this may create an unusable destination image\n");

        return ret;

    } else if (ret < 0 && target->backing) {

        /* Not fatal; just trudge on ahead. */

        return BACKUP_CLUSTER_SIZE_DEFAULT;

    }



    return MAX(BACKUP_CLUSTER_SIZE_DEFAULT, bdi.cluster_size);

}



BlockJob *backup_job_create(const char *job_id, BlockDriverState *bs,

                  BlockDriverState *target, int64_t speed,

                  MirrorSyncMode sync_mode, BdrvDirtyBitmap *sync_bitmap,
@@ -508,9 +544,10 @@ BlockJob *backup_job_create(const char *job_id, BlockDriverState *bs, 
                  JobTxn *txn, Error **errp)

{

    int64_t len;

    BlockDriverInfo bdi;

    BackupBlockJob *job = NULL;

    int ret;

    int64_t cluster_size;

    HBitmap *copy_bitmap = NULL;



    assert(bs);

    assert(target);
@@ -572,6 +609,13 @@ BlockJob *backup_job_create(const char *job_id, BlockDriverState *bs, 
        goto error;

    }



    cluster_size = backup_calculate_cluster_size(target, errp);

    if (cluster_size < 0) {

        goto error;

    }



    copy_bitmap = hbitmap_alloc(len, ctz32(cluster_size));



    /* job->len is fixed, so we can't allow resize */

    job = block_job_create(job_id, &backup_job_driver, txn, bs,

                           BLK_PERM_CONSISTENT_READ,
@@ -600,35 +644,9 @@ BlockJob *backup_job_create(const char *job_id, BlockDriverState *bs, 


    /* Detect image-fleecing (and similar) schemes */

    job->serialize_target_writes = bdrv_chain_contains(target, bs);



    /* If there is no backing file on the target, we cannot rely on COW if our

     * backup cluster size is smaller than the target cluster size. Even for

     * targets with a backing file, try to avoid COW if possible. */

    ret = bdrv_get_info(target, &bdi);

    if (ret == -ENOTSUP && !target->backing) {

        /* Cluster size is not defined */

        warn_report("The target block device doesn't provide "

                    "information about the block size and it doesn't have a "

                    "backing file. The default block size of %u bytes is "

                    "used. If the actual block size of the target exceeds "

                    "this default, the backup may be unusable",

                    BACKUP_CLUSTER_SIZE_DEFAULT);

        job->cluster_size = BACKUP_CLUSTER_SIZE_DEFAULT;

    } else if (ret < 0 && !target->backing) {

        error_setg_errno(errp, -ret,

            "Couldn't determine the cluster size of the target image, "

            "which has no backing file");

        error_append_hint(errp,

            "Aborting, since this may create an unusable destination image\n");

        goto error;

    } else if (ret < 0 && target->backing) {

        /* Not fatal; just trudge on ahead. */

        job->cluster_size = BACKUP_CLUSTER_SIZE_DEFAULT;

    } else {

        job->cluster_size = MAX(BACKUP_CLUSTER_SIZE_DEFAULT, bdi.cluster_size);

    }



    job->copy_bitmap = hbitmap_alloc(len, ctz32(job->cluster_size));

    job->cluster_size = cluster_size;

    job->copy_bitmap = copy_bitmap;

    copy_bitmap = NULL;

    job->use_copy_range = true;

    job->copy_range_size = MIN_NON_ZERO(blk_get_max_transfer(job->common.blk),

                                        blk_get_max_transfer(job->target));
@@ -644,6 +662,10 @@ BlockJob *backup_job_create(const char *job_id, BlockDriverState *bs, 
    return &job->common;



 error:

    if (copy_bitmap) {

        assert(!job || !job->copy_bitmap);

        hbitmap_free(copy_bitmap);

    }

    if (sync_bitmap) {

        bdrv_reclaim_dirty_bitmap(bs, sync_bitmap, NULL);

    }