47 lines
1.0 KiB
Go
47 lines
1.0 KiB
Go
//+build linux
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package local
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import (
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"os"
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"sync/atomic"
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"github.com/rclone/rclone/fs"
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"golang.org/x/sys/unix"
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)
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var (
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fallocFlags = [...]uint32{
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unix.FALLOC_FL_KEEP_SIZE, // Default
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unix.FALLOC_FL_KEEP_SIZE | unix.FALLOC_FL_PUNCH_HOLE, // for ZFS #3066
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}
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fallocFlagsIndex int32
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)
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// preAllocate the file for performance reasons
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func preAllocate(size int64, out *os.File) error {
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if size <= 0 {
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return nil
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}
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index := atomic.LoadInt32(&fallocFlagsIndex)
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again:
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if index >= int32(len(fallocFlags)) {
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return nil // Fallocate is disabled
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}
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flags := fallocFlags[index]
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err := unix.Fallocate(int(out.Fd()), flags, 0, size)
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if err == unix.ENOTSUP {
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// Try the next flags combination
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index++
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atomic.StoreInt32(&fallocFlagsIndex, index)
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fs.Debugf(nil, "preAllocate: got error on fallocate, trying combination %d/%d: %v", index, len(fallocFlags), err)
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goto again
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}
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// FIXME could be doing something here
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// if err == unix.ENOSPC {
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// log.Printf("No space")
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// }
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return err
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}
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