diff options
| -rw-r--r-- | block/backup.c | 20 |
1 files changed, 14 insertions, 6 deletions
diff --git a/block/backup.c b/block/backup.c index f3e4e814b6..319fc922e8 100644 --- a/block/backup.c +++ b/block/backup.c @@ -47,6 +47,8 @@ typedef struct BackupBlockJob { HBitmap *copy_bitmap; bool use_copy_range; int64_t copy_range_size; + + bool serialize_target_writes; } BackupBlockJob; static const BlockJobDriver backup_job_driver; @@ -102,6 +104,8 @@ static int coroutine_fn backup_cow_with_bounce_buffer(BackupBlockJob *job, QEMUIOVector qiov; BlockBackend *blk = job->common.blk; int nbytes; + int read_flags = is_write_notifier ? BDRV_REQ_NO_SERIALISING : 0; + int write_flags = job->serialize_target_writes ? BDRV_REQ_SERIALISING : 0; hbitmap_reset(job->copy_bitmap, start / job->cluster_size, 1); nbytes = MIN(job->cluster_size, job->len - start); @@ -112,8 +116,7 @@ static int coroutine_fn backup_cow_with_bounce_buffer(BackupBlockJob *job, iov.iov_len = nbytes; qemu_iovec_init_external(&qiov, &iov, 1); - ret = blk_co_preadv(blk, start, qiov.size, &qiov, - is_write_notifier ? BDRV_REQ_NO_SERIALISING : 0); + ret = blk_co_preadv(blk, start, qiov.size, &qiov, read_flags); if (ret < 0) { trace_backup_do_cow_read_fail(job, start, ret); if (error_is_read) { @@ -124,11 +127,11 @@ static int coroutine_fn backup_cow_with_bounce_buffer(BackupBlockJob *job, if (qemu_iovec_is_zero(&qiov)) { ret = blk_co_pwrite_zeroes(job->target, start, - qiov.size, BDRV_REQ_MAY_UNMAP); + qiov.size, write_flags | BDRV_REQ_MAY_UNMAP); } else { ret = blk_co_pwritev(job->target, start, - qiov.size, &qiov, - job->compress ? BDRV_REQ_WRITE_COMPRESSED : 0); + qiov.size, &qiov, write_flags | + (job->compress ? BDRV_REQ_WRITE_COMPRESSED : 0)); } if (ret < 0) { trace_backup_do_cow_write_fail(job, start, ret); @@ -156,6 +159,8 @@ static int coroutine_fn backup_cow_with_offload(BackupBlockJob *job, int nr_clusters; BlockBackend *blk = job->common.blk; int nbytes; + int read_flags = is_write_notifier ? BDRV_REQ_NO_SERIALISING : 0; + int write_flags = job->serialize_target_writes ? BDRV_REQ_SERIALISING : 0; assert(QEMU_IS_ALIGNED(job->copy_range_size, job->cluster_size)); nbytes = MIN(job->copy_range_size, end - start); @@ -163,7 +168,7 @@ static int coroutine_fn backup_cow_with_offload(BackupBlockJob *job, hbitmap_reset(job->copy_bitmap, start / job->cluster_size, nr_clusters); ret = blk_co_copy_range(blk, start, job->target, start, nbytes, - is_write_notifier ? BDRV_REQ_NO_SERIALISING : 0, 0); + read_flags, write_flags); if (ret < 0) { trace_backup_do_cow_copy_range_fail(job, start, ret); hbitmap_set(job->copy_bitmap, start / job->cluster_size, @@ -701,6 +706,9 @@ BlockJob *backup_job_create(const char *job_id, BlockDriverState *bs, sync_bitmap : NULL; job->compress = compress; + /* 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. */ |