From 126d5b2e55dca93e024f5654fed6fae37a012369 Mon Sep 17 00:00:00 2001
From: salmonik <salmonik@tuta.io>
Date: Mon, 17 Aug 2026 19:56:24 +0200
Subject: Terminal-app design (ADR 0005) + disk-write controller

- ADR 0005: persistent home terminal (full-screen, chrome-less,
  bottom-pinned), F1 terminal windows, per-instance vt/tty/shell,
  queue-based input for all terminals, and the disk controller
- Glossary: add the Terminal term; update Task/App for the new model
- Add a re-entrant disk lock (DiskGuard over the preemption-depth
  counter) and wrap all fs/fat mutating operations per-call
---
 rsnix/src/fs.rs | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

(limited to 'rsnix/src/fs.rs')

diff --git a/rsnix/src/fs.rs b/rsnix/src/fs.rs
index 24d8fcd..3585c00 100644
--- a/rsnix/src/fs.rs
+++ b/rsnix/src/fs.rs
@@ -203,6 +203,7 @@ pub fn init() -> (usize, usize) {
 /// its backing info), and tombstone nodes whose volume was unmounted.
 /// Returns (added, removed) node ops.
 pub fn rescan_disks() -> (usize, usize) {
+    let _lock = crate::fat::DiskGuard::acquire();
     let mut added = 0usize;
     let mut removed = 0usize;
     let disk_dir = match lookup(0, "disk") {
@@ -428,6 +429,7 @@ pub fn read(h: usize, buf: &mut [u8], pos: u64) -> Result<usize, ()> {
 }
 
 pub fn write(h: usize, buf: &[u8], pos: u64) -> Result<usize, ()> {
+    let _lock = crate::fat::DiskGuard::acquire();
     match &mut nodes()[h].data {
         NodeData::Regular(v) => {
             let p = pos as usize;
@@ -533,7 +535,10 @@ pub fn write_crash_log(lines: &[&str]) {
     let mut tb = [0u8; 48];
     let tn = {
         let mut w = crate::strbuf::FmtBuf::new(&mut tb);
-        let _ = core::fmt::write(&mut w, core::format_args!("crashlog: vol {} ({})\r\n", vol, label));
+        let _ = core::fmt::write(
+            &mut w,
+            core::format_args!("crashlog: vol {} ({})\r\n", vol, label),
+        );
         w.len()
     };
     crate::serial::write_raw(core::str::from_utf8(&tb[..tn]).unwrap_or("?"));
@@ -555,7 +560,9 @@ pub fn write_crash_log(lines: &[&str]) {
 }
 
 /// Truncate/resize a regular file.
-pub fn set_len(h: usize, len: u64) -> Result<(), ()> {    match &mut nodes()[h].data {
+pub fn set_len(h: usize, len: u64) -> Result<(), ()> {
+    let _lock = crate::fat::DiskGuard::acquire();
+    match &mut nodes()[h].data {
         NodeData::Regular(v) => {
             v.resize(len as usize, 0);
             Ok(())
@@ -567,6 +574,7 @@ pub fn set_len(h: usize, len: u64) -> Result<(), ()> {    match &mut nodes()[h].
 
 /// Create a Regular or Dir child.  Fails if the name exists or is invalid.
 pub fn create(parent: usize, name: &str, kind: FileType) -> Result<usize, ()> {
+    let _lock = crate::fat::DiskGuard::acquire();
     if name.is_empty() || name.contains('/') || kind == FileType::Char {
         return Err(());
     }
@@ -608,6 +616,7 @@ pub fn create(parent: usize, name: &str, kind: FileType) -> Result<usize, ()> {
 
 /// Remove a regular file or an empty directory (tombstone).
 pub fn remove(h: usize) -> Result<(), ()> {
+    let _lock = crate::fat::DiskGuard::acquire();
     // Disk nodes: delete through the FAT volume (dirs must be empty).
     if let NodeData::Disk(i) = &nodes()[h].data {
         if i.name.is_empty() {
-- 
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