178debe435
When we map a file for generating the DAG, we do a simple truncate to e.g. 1Gb. This is fine, even if we have nowhere near 1Gb disk available, as the actual file doesn't take up the full 1Gb, merely a few bytes. When we start generating into it, however, it eventually crashes with a unexpected fault address . This change fixes it (on linux systems) by using the Fallocate syscall, which preallocates suffcient space on disk to avoid that situation. Co-authored-by: Felix Lange <fjl@twurst.com>
36 lines
1.3 KiB
Go
36 lines
1.3 KiB
Go
// Copyright 2021 The go-ethereum Authors
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// This file is part of the go-ethereum library.
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//
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// The go-ethereum library is free software: you can redistribute it and/or modify
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// it under the terms of the GNU Lesser General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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//
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// The go-ethereum library is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU Lesser General Public License for more details.
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//
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// You should have received a copy of the GNU Lesser General Public License
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// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
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//go:build linux
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// +build linux
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package ethash
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import (
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"os"
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"golang.org/x/sys/unix"
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)
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// ensureSize expands the file to the given size. This is to prevent runtime
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// errors later on, if the underlying file expands beyond the disk capacity,
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// even though it ostensibly is already expanded, but due to being sparse
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// does not actually occupy the full declared size on disk.
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func ensureSize(f *os.File, size int64) error {
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// Docs: https://www.man7.org/linux/man-pages/man2/fallocate.2.html
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return unix.Fallocate(int(f.Fd()), 0, 0, size)
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}
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