Merge pull request #996 from karalabe/fix-potential-crosscheck-race

eth/downloader: circumvent download race between crosscheck and hashes
This commit is contained in:
Jeffrey Wilcke 2015-05-15 11:23:44 -07:00
commit 82c0780f81

View File

@ -284,12 +284,14 @@ func (d *Downloader) fetchHashes(p *peer, h common.Hash) error {
} }
if !done { if !done {
// Try and fetch a random block to verify the hash batch // Try and fetch a random block to verify the hash batch
cross := inserts[rand.Intn(len(inserts))] // Skip the last hash as the cross check races with the next hash fetch
glog.V(logger.Detail).Infof("Cross checking (%s) with %x", active.id, cross) if len(inserts) > 1 {
cross := inserts[rand.Intn(len(inserts)-1)]
d.checks[cross] = time.Now().Add(blockTTL) glog.V(logger.Detail).Infof("Cross checking (%s) with %x", active.id, cross)
active.getBlocks([]common.Hash{cross})
d.checks[cross] = time.Now().Add(blockTTL)
active.getBlocks([]common.Hash{cross})
}
// Also fetch a fresh // Also fetch a fresh
active.getHashes(head) active.getHashes(head)
continue continue