eth/protocols/snap: save nodes on right boundary in hash mode

[rjl493456442]

This pull request fixes an issue in hash gentrie.

In hash-mode, no matter the gentrie is complete or not, all the nodes on the right boundary should be flushed into disk if commit is called. As the garbage nodes will be unlinked from the trie by state healer.

Currently, if the right boundary of gentrie is claimed as incomplete, nodes on it are silently discarded. Given that the nodes on incomplete boundary are usually useless, but still the behavior should be aligned in hash gentrie.

[holiman]

LGTM

[rjl493456442]

It panics, need investigation

May 24 10:25:09 bench05.ethdevops.io geth panic: trying to insert into hash
May 24 10:25:09 bench05.ethdevops.io geth   panic: trying to insert into hash
May 24 10:25:09 bench05.ethdevops.io geth goroutine 158811 [running]:
May 24 10:25:09 bench05.ethdevops.io geth github.com/ethereum/go-ethereum/trie.(*StackTrie).insert(0xc000a36d50, 0xc00015d200, {0xc000d9efa0, 0x40, 0x41}, {0xc000d9ef50, 0x4d, 0x4d}, {0x0, 0x0, ...})
May 24 10:25:09 bench05.ethdevops.io geth   github.com/ethereum/go-ethereum/trie/stacktrie.go:284 +0x51d
May 24 10:25:09 bench05.ethdevops.io geth github.com/ethereum/go-ethereum/trie.(*StackTrie).Update(0xc000a36d50, {0xc008b84420, 0x20, 0x715abf?}, {0xc000d9ef50, 0x4d, 0x4d})
May 24 10:25:09 bench05.ethdevops.io geth   github.com/ethereum/go-ethereum/trie/stacktrie.go:77 +0x2fb
May 24 10:25:09 bench05.ethdevops.io geth github.com/ethereum/go-ethereum/eth/protocols/snap.(*hashTrie).update(0xc002c017f0?, {0xc008b84420?, 0xf3822751a1bee7a1?, 0xe9a4d9952dd671fe?}, {0xc000d9ef50?, 0xc007684fa0?, 0xc002c017f0?})
May 24 10:25:09 bench05.ethdevops.io geth   github.com/ethereum/go-ethereum/eth/protocols/snap/gentrie.go:278 +0x25
May 24 10:25:09 bench05.ethdevops.io geth github.com/ethereum/go-ethereum/eth/protocols/snap.(*Syncer).forwardAccountTask(0xc0005d4008, 0xc000280b00)
May 24 10:25:09 bench05.ethdevops.io geth   github.com/ethereum/go-ethereum/eth/protocols/snap/sync.go:2434 +0x3a3
May 24 10:25:09 bench05.ethdevops.io geth github.com/ethereum/go-ethereum/eth/protocols/snap.(*Syncer).Sync.func1()
May 24 10:25:09 bench05.ethdevops.io geth   github.com/ethereum/go-ethereum/eth/protocols/snap/sync.go:630 +0x3e
May 24 10:25:09 bench05.ethdevops.io geth panic({0x176ac00?, 0x1ffbd30?})
May 24 10:25:09 bench05.ethdevops.io geth   runtime/panic.go:770 +0x132
May 24 10:25:09 bench05.ethdevops.io geth github.com/ethereum/go-ethereum/trie.(*StackTrie).insert(0xc000a36c90, 0xc00015d140, {0xc0079d9d60, 0x40, 0x41}, {0xc0079d9d10, 0x46, 0x46}, {0x0, 0x0, ...})
May 24 10:25:09 bench05.ethdevops.io geth   github.com/ethereum/go-ethereum/trie/stacktrie.go:284 +0x51d
May 24 10:25:09 bench05.ethdevops.io geth github.com/ethereum/go-ethereum/trie.(*StackTrie).Update(0xc000a36c90, {0xc0079d31a0, 0x20, 0x715abf?}, {0xc0079d9d10, 0x46, 0x46})
May 24 10:25:09 bench05.ethdevops.io geth   github.com/ethereum/go-ethereum/trie/stacktrie.go:77 +0x2fb
May 24 10:25:09 bench05.ethdevops.io geth github.com/ethereum/go-ethereum/eth/protocols/snap.(*hashTrie).update(0xc0014a3590?, {0xc0079d31a0?, 0x161ac922b365861f?, 0x15ab6be72db7f643?}, {0xc0079d9d10?, 0xc00053a180?, 0xc0014a3590?})
May 24 10:25:09 bench05.ethdevops.io geth   github.com/ethereum/go-ethereum/eth/protocols/snap/gentrie.go:278 +0x25
May 24 10:25:09 bench05.ethdevops.io geth github.com/ethereum/go-ethereum/eth/protocols/snap.(*Syncer).forwardAccountTask(0xc0005d4008, 0xc000280a00)
May 24 10:25:09 bench05.ethdevops.io geth   github.com/ethereum/go-ethereum/eth/protocols/snap/sync.go:2434 +0x3a3
May 24 10:25:09 bench05.ethdevops.io geth github.com/ethereum/go-ethereum/eth/protocols/snap.(*Syncer).processStorageResponse(0xc0005d4008, 0xc007416b80)
May 24 10:25:09 bench05.ethdevops.io geth   github.com/ethereum/go-ethereum/eth/protocols/snap/sync.go:2269 +0x755
May 24 10:25:09 bench05.ethdevops.io geth github.com/ethereum/go-ethereum/eth/protocols/snap.(*Syncer).Sync(0xc0005d4008, {0xa7, 0x8f, 0xf0, 0xee, 0xa5, 0xa8, 0xfb, 0xd7, 0xe8, ...}, ...)
May 24 10:25:09 bench05.ethdevops.io geth   github.com/ethereum/go-ethereum/eth/protocols/snap/sync.go:743 +0xddf
May 24 10:25:09 bench05.ethdevops.io geth github.com/ethereum/go-ethereum/eth/downloader.(*stateSync).run(...)
May 24 10:25:09 bench05.ethdevops.io geth   github.com/ethereum/go-ethereum/eth/downloader/statesync.go:107
May 24 10:25:09 bench05.ethdevops.io geth created by github.com/ethereum/go-ethereum/eth/downloader.(*Downloader).runStateSync in goroutine 33642
May 24 10:25:09 bench05.ethdevops.io geth   github.com/ethereum/go-ethereum/eth/downloader/statesync.go:63 +0x112