diff options
| -rw-r--r-- | block/backup.c | 60 |
1 files changed, 23 insertions, 37 deletions
diff --git a/block/backup.c b/block/backup.c index 98a2d2b070..78f1b79354 100644 --- a/block/backup.c +++ b/block/backup.c @@ -368,6 +368,22 @@ static bool coroutine_fn yield_and_check(BackupBlockJob *job) return false; } +static bool bdrv_is_unallocated_range(BlockDriverState *bs, + int64_t offset, int64_t bytes) +{ + int64_t end = offset + bytes; + + while (offset < end && !bdrv_is_allocated(bs, offset, bytes, &bytes)) { + if (bytes == 0) { + return true; + } + offset += bytes; + bytes = end - offset; + } + + return offset >= end; +} + static int coroutine_fn backup_run_incremental(BackupBlockJob *job) { int ret; @@ -453,49 +469,19 @@ static int coroutine_fn backup_run(Job *job, Error **errp) for (offset = 0; offset < s->len; offset += s->cluster_size) { bool error_is_read; - int alloced = 0; if (yield_and_check(s)) { break; } - if (s->sync_mode == MIRROR_SYNC_MODE_TOP) { - int i; - int64_t n; - - /* Check to see if these blocks are already in the - * backing file. */ - - for (i = 0; i < s->cluster_size;) { - /* bdrv_is_allocated() only returns true/false based - * on the first set of sectors it comes across that - * are are all in the same state. - * For that reason we must verify each sector in the - * backup cluster length. We end up copying more than - * needed but at some point that is always the case. */ - alloced = - bdrv_is_allocated(bs, offset + i, - s->cluster_size - i, &n); - i += n; - - if (alloced || n == 0) { - break; - } - } - - /* If the above loop never found any sectors that are in - * the topmost image, skip this backup. */ - if (alloced == 0) { - continue; - } - } - /* FULL sync mode we copy the whole drive. */ - if (alloced < 0) { - ret = alloced; - } else { - ret = backup_do_cow(s, offset, s->cluster_size, - &error_is_read, false); + if (s->sync_mode == MIRROR_SYNC_MODE_TOP && + bdrv_is_unallocated_range(bs, offset, s->cluster_size)) + { + continue; } + + ret = backup_do_cow(s, offset, s->cluster_size, + &error_is_read, false); if (ret < 0) { /* Depending on error action, fail now or retry cluster */ BlockErrorAction action = |