[PATCH v1 proxmox 2/2] fix #7690: proxmox-sys: close fd before rename/unlink in replace_file

[Robert Obkircher <r.obkircher@proxmox.com>]

Fix the rename operation on WORM file systems and allow FUSE file
systems to unlink without creating temporary .fuse_hidden files.

Closing the fd earlier shouldn't have any noticeable effects on normal
file systems, because the path-based rename and unlink operations are
completely separate from the content.

Link: https://bugzilla.proxmox.com/show_bug.cgi?id=7690
Signed-off-by: Robert Obkircher <r.obkircher@proxmox.com>
---
 proxmox-sys/src/fs/file.rs | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/proxmox-sys/src/fs/file.rs b/proxmox-sys/src/fs/file.rs
index 533e0896..03223e5a 100644
--- a/proxmox-sys/src/fs/file.rs
+++ b/proxmox-sys/src/fs/file.rs
@@ -180,6 +180,7 @@ pub fn replace_file<P: AsRef<Path>>(
     let (mut file, tmp_path) = make_tmp_file(&path, options)?;
 
     if let Err(err) = file.write_all(data) {
+        drop(file);
         let _ = unistd::unlink(&tmp_path);
         bail!("write failed: {}", err);
     }
@@ -187,11 +188,16 @@ pub fn replace_file<P: AsRef<Path>>(
     if fsync {
         // make sure data is on disk
         if let Err(err) = nix::unistd::fsync(file.as_raw_fd()) {
+            drop(file);
             let _ = unistd::unlink(&tmp_path);
             bail!("fsync failed: {}", err);
         }
     }
 
+    // Allow WORM file systems to commit the contents before the rename
+    // and prevent temporary .fuse_hidden* files created by unlink.
+    drop(file);
+
     if let Err(err) = std::fs::rename(&tmp_path, &path) {
         let _ = unistd::unlink(&tmp_path);
         bail!(
-- 
2.47.3