From ec04ea81f2e738f91785e63fd878b54bbf43d8de Mon Sep 17 00:00:00 2001
From: Christian Ebner <c.ebner@proxmox.com>
Date: Fri, 6 Sep 2019 11:38:27 +0200
Subject: [PATCH] src/pxar/fuse.rs: Refactor run_in_context and remove
 inode_to_offset and offset_to_inode

as their functionality is used only once so it makes more sense to keep them
inline.

Signed-off-by: Christian Ebner <c.ebner@proxmox.com>
---
 src/pxar/fuse.rs | 75 +++++++++++++++++-------------------------------
 1 file changed, 27 insertions(+), 48 deletions(-)

diff --git a/src/pxar/fuse.rs b/src/pxar/fuse.rs
index 5927a54c..56dbf60d 100644
--- a/src/pxar/fuse.rs
+++ b/src/pxar/fuse.rs
@@ -27,6 +27,7 @@ use super::format_definition::PxarGoodbyeItem;
 /// required.
 const FUSE_ROOT_ID: u64 = 1;
 
+const GOODBYE_ITEM_SIZE: u64 = std::mem::size_of::<PxarGoodbyeItem>() as u64;
 /// Callback function for `super::decoder::Decoder`.
 ///
 /// At the moment, this is only needed to satisfy the `SequentialDecoder`.
@@ -252,47 +253,19 @@ impl Drop for Session {
     }
 }
 
-const GOODBYE_ITEM_SIZE: u64 = std::mem::size_of::<PxarGoodbyeItem>() as u64;
-
-/// Converts the inode to the file offset
-///
-/// Since the inodes are defined as the file offset,
-/// this simply returns the inode value.
-/// The only exception to this is the inode of root,
-/// which is defined as `FUSE_ROOT_ID` by libfuse and therefore mapped
-/// to the roots goodbye table tail.
-fn inode_to_offset(inode: u64, root_end: u64) -> u64 {
-    if inode == FUSE_ROOT_ID {
-        root_end - GOODBYE_ITEM_SIZE
-    } else {
-        inode
-    }
-}
-
-/// Converts the file offset to an inode
-///
-/// Since the inodes are defined as the file offset,
-/// this simply returns the offset value.
-/// The only exception to this is the inode of root,
-/// which is defined as `FUSE_ROOT_ID` by libfuse, so the roots goodbye tail
-/// offset gets mapped to `FUSE_ROOT_ID`.
-pub(crate) fn offset_to_inode(offset: u64, root_end: u64) -> u64 {
-    if offset == root_end - GOODBYE_ITEM_SIZE {
-        FUSE_ROOT_ID
-    } else {
-        offset
-    }
-}
-
 /// Creates a context providing an exclusive mutable reference to the decoder.
 ///
 /// Each callback function needing access to the decoder can easily get an
 /// exclusive handle by running the code inside this context.
 /// Responses with error code can easily be generated by returning with the
 /// error code.
-fn run_in_context<F>(req: Request, code: F)
+/// The error code will be used to reply to libfuse.
+fn run_in_context<F>(req: Request, inode: u64, code: F)
 where
-    F: FnOnce(&mut Decoder<BufReader<File>, fn(&Path) -> Result<(), Error>>) -> Result<(), i32>,
+    F: FnOnce(
+        &mut Decoder<BufReader<File>, fn(&Path) -> Result<(), Error>>,
+        u64,
+    ) -> Result<(), i32>,
 {
     let ptr = unsafe {
         fuse_req_userdata(req)
@@ -301,8 +274,14 @@ where
     let boxed_decoder = unsafe { Box::from_raw(ptr) };
     let result = boxed_decoder
         .lock()
-        .map(|mut decoder| code(&mut decoder))
-        .unwrap_or(Err(libc::ENOENT));
+        .map(|mut decoder| {
+            let ino_offset = match inode {
+                FUSE_ROOT_ID => decoder.root_end_offset() - GOODBYE_ITEM_SIZE,
+                _ => inode,
+            };
+            code(&mut decoder, ino_offset)
+        })
+        .unwrap_or(Err(libc::EIO));
 
     if let Err(err) = result {
         unsafe {
@@ -327,48 +306,48 @@ extern "C" fn destroy(decoder: MutPtr) {
     }
 }
 
-extern "C" fn lookup(req: Request, _parent: u64, _name: StrPtr) {
-    run_in_context(req, |_decoder| {
+extern "C" fn lookup(req: Request, parent: u64, _name: StrPtr) {
+    run_in_context(req, parent, |_decoder, _ino_offset| {
         // code goes here
 
         Err(libc::ENOENT)
     });
 }
 
-extern "C" fn getattr(req: Request, _inode: u64, _fileinfo: MutPtr) {
-    run_in_context(req, |_decoder| {
+extern "C" fn getattr(req: Request, inode: u64, _fileinfo: MutPtr) {
+    run_in_context(req, inode, |_decoder, _ino_offset| {
         // code goes here
 
         Err(libc::ENOENT)
     });
 }
 
-extern "C" fn open(req: Request, _inode: u64, _fileinfo: MutPtr) {
-    run_in_context(req, |_decoder| {
+extern "C" fn open(req: Request, inode: u64, _fileinfo: MutPtr) {
+    run_in_context(req, inode, |_decoder, _ino_offset| {
         // code goes here
 
         Err(libc::ENOENT)
     });
 }
 
-extern "C" fn read(req: Request, _inode: u64, _size: size_t, _offset: c_int, _fileinfo: MutPtr) {
-    run_in_context(req, |_decoder| {
+extern "C" fn read(req: Request, inode: u64, _size: size_t, _offset: c_int, _fileinfo: MutPtr) {
+    run_in_context(req, inode, |_decoder, _ino_offset| {
         // code goes here
 
         Err(libc::ENOENT)
     });
 }
 
-extern "C" fn opendir(req: Request, _inode: u64, _fileinfo: MutPtr) {
-    run_in_context(req, |_decoder| {
+extern "C" fn opendir(req: Request, inode: u64, _fileinfo: MutPtr) {
+    run_in_context(req, inode, |_decoder, _ino_offset| {
         // code goes here
 
         Err(libc::ENOENT)
     });
 }
 
-extern "C" fn readdir(req: Request, _inode: u64, _size: size_t, _offset: c_int, _fileinfo: MutPtr) {
-    run_in_context(req, |_decoder| {
+extern "C" fn readdir(req: Request, inode: u64, _size: size_t, _offset: c_int, _fileinfo: MutPtr) {
+    run_in_context(req, inode, |_decoder, _ino_offset| {
         // code goes here
 
         Err(libc::ENOENT)