Move pathfs_frontend to internal/fusefrontend

"git status" for reference:

renamed:    pathfs_frontend/args.go -> internal/fusefrontend/args.go
renamed:    pathfs_frontend/compat_darwin.go -> internal/fusefrontend/compat_darwin.go
renamed:    pathfs_frontend/compat_linux.go -> internal/fusefrontend/compat_linux.go
renamed:    pathfs_frontend/file.go -> internal/fusefrontend/file.go
renamed:    pathfs_frontend/file_holes.go -> internal/fusefrontend/file_holes.go
renamed:    pathfs_frontend/fs.go -> internal/fusefrontend/fs.go
renamed:    pathfs_frontend/fs_dir.go -> internal/fusefrontend/fs_dir.go
renamed:    pathfs_frontend/names.go -> internal/fusefrontend/names.go
renamed:    pathfs_frontend/write_lock.go -> internal/fusefrontend/write_lock.go
modified:   main.go

1 files changed, 18 insertions, 0 deletions

diff --git a/internal/fusefrontend/compat_linux.go b/internal/fusefrontend/compat_linux.go
new file mode 100644
index 0000000..4108792
--- /dev/null
+++ b/internal/fusefrontend/compat_linux.go
@@ -0,0 +1,18 @@
+package fusefrontend
+
+import "syscall"
+
+// 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
+		}
+		return err
+	}
+}