pxar::decoder: Return the correct symlink target size.

This eliminates also repeated calls to readlink in fuse, which occur when the
preallocated buffer to store the symlink target path is to small.

Signed-off-by: Christian Ebner <c.ebner@proxmox.com>

src/pxar/decoder.rs

@@ -137,13 +137,12 @@ impl Decoder {
         check_ca_header::<PxarEntry>(&head, PXAR_ENTRY)?;
         let entry: PxarEntry = self.inner.read_item()?;
         let (header, xattr) = self.inner.read_attributes()?;
-        let (size, payload_offset) = match header.htype {
-            PXAR_PAYLOAD => (header.size - HEADER_SIZE, Some(self.seek(SeekFrom::Current(0))?)),
-            _ => (0, None),
-        };
-        let target = match header.htype {
-            PXAR_SYMLINK => Some(self.inner.read_link(header.size)?),
-            _ => None,
+        let (size, payload_offset, target) = match header.htype {
+            PXAR_PAYLOAD =>
+                (header.size - HEADER_SIZE, Some(self.seek(SeekFrom::Current(0))?), None),
+            PXAR_SYMLINK =>
+                (header.size - HEADER_SIZE, None, Some(self.inner.read_link(header.size)?)),
+            _ => (0, None, None),
         };
 
         Ok(DirectoryEntry {