libgocryptfs/internal/fusefrontend/compat_linux.go

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package fusefrontend
import (
"sync"
"syscall"
)
import "github.com/rfjakob/gocryptfs/internal/tlog"
var preallocWarn sync.Once
// prealloc - preallocate space without changing the file size. This prevents
// us from running out of space in the middle of an operation.
func prealloc(fd int, off int64, len int64) (err error) {
for {
err = syscall.Fallocate(fd, FALLOC_FL_KEEP_SIZE, off, len)
if err == syscall.EINTR {
// fallocate, like many syscalls, can return EINTR. This is not an
// error and just signifies that the operation was interrupted by a
// signal and we should try again.
continue
}
if err == syscall.EOPNOTSUPP {
// ZFS does not support fallocate which caused gocryptfs to abort
// every write operation: https://github.com/rfjakob/gocryptfs/issues/22
preallocWarn.Do(func() {
tlog.Warn.Printf("Warning: The underlying filesystem " +
"does not support fallocate(2). gocryptfs will continue working " +
"but is no longer resistant against out-of-space errors.\n")
})
return nil
}
return err
}
}