wired new locations into gui, fuse acceptance with new permission based mounts

README.md

@@ -9,6 +9,7 @@ A fast, unofficial Proton Drive client for Linux. This client features an advanc
 - **Non-Blocking GTK4 Desktop App**: Browse files, manage pins, configure options, and monitor active transfers through a modern, native GUI with a fully non-blocking asynchronous main loop.
 - **Shared Links & Invites**: Browse files shared with you by other users, and view/manage your own public shared links directly in the GUI.
 - **Local Backup (Computers)**: Sync and back up local directories (like Downloads, Documents, Pictures, etc.) directly to your Proton Drive account.
+- **Locations**: One page (and `pdfs locations`) listing every place Proton Drive occupies on this machine — the main mount plus each backed-up folder — with its mode, sync state, and whether it is read-only. Switching a folder between a full local copy and on-demand happens here.
 - **System Tray Integration**: Background indicator for status monitoring, quick actions, and fast sync controls.
 - **Unified Search Launcher (HUD)**: A resident Google Drive-style launcher (`pdfs-prompt`) that searches Proton Drive and local files together, ranks the best matches, tolerates abbreviations and typos, and is ideal for a system-wide hotkey.
 - **Secure Credential Storage**: Integrates with the system Secret Service (GNOME Keyring, KWallet, etc.) with smart in-memory credential caching to avoid UI thread blockages.

crates/pdfs-cli/src/main.rs

@@ -905,7 +905,15 @@ fn cmd_shared_with_me(uid: Option<String>) -> Result<()> {
         CtlResponse::Entries { entries } => {
             for e in entries {
                 let kind = if e.is_dir { "d" } else { "-" };
-                println!("{kind} {:>12}  {}  [{}]", e.size, e.name, e.uid);
+                // My role decides whether this is writable at all, so it is
+                // printed whenever the API reported one; an empty role prints
+                // nothing rather than a guess.
+                let role = if e.role.is_empty() {
+                    String::new()
+                } else {
+                    format!("  ({})", e.role)
+                };
+                println!("{kind} {:>12}  {}{role}  [{}]", e.size, e.name, e.uid);
             }
         }
         CtlResponse::Error { message, kind } => bail!("{}", cli_error(kind, &message)),

crates/pdfs-core/src/control.rs

@@ -706,6 +706,12 @@ pub struct DirEntry {
     /// browser.
     #[serde(default)]
     pub path: String,
+    /// My role on this node when it is reached through a share I accepted —
+    /// `"viewer"`, `"editor"`, `"admin"`, or empty for content I own (where the
+    /// question does not arise) and for a share whose role the API did not
+    /// report. Defaulted for wire-compat with clients/daemons predating it.
+    #[serde(default)]
+    pub role: String,
 }
 
 /// One hit in a [`Request::Search`] result. Like [`DirEntry`] but carries the

crates/pdfs-fuse/src/lib.rs

@@ -2956,6 +2956,9 @@ impl Core {
                 // Listing entries live in the requested dir; the caller derives
                 // the path from its name. Left empty.
                 path: String::new(),
+                // My own tree: a role only means something under a share, and
+                // this listing never crosses into one.
+                role: String::new(),
             })
             .collect())
     }
@@ -3415,6 +3418,7 @@ impl Core {
                 cached: false,
                 uid: item.uid,
                 path: String::new(),
+                role: String::new(),
             })
             .collect())
     }

crates/pdfs-fuse/src/sharing.rs

@@ -19,10 +19,15 @@ use proton_drive_rs::Node;
 
 use super::{Core, ROOT_INO, node_size, parse_uid, public_link_info, role_from_str, role_to_str};
 
-/// A node from a *shared* listing as a [`DirEntry`]. Shared nodes live outside
-/// the mount, so the entry is uid-addressed: `path` is empty, and the local-state
-/// flags (`pinned`, `cached`) are false — they describe my own tree, not this one.
-fn shared_entry(n: Node) -> DirEntry {
+/// A node from a *shared* listing as a [`DirEntry`].
+///
+/// Still uid-addressed — that is the only handle a foreign-volume node is
+/// guaranteed to have — but `path` is filled in when the node is resident under
+/// the synthetic `Shared with me/` directory, which is what lets a front-end
+/// offer path-keyed actions on it. The local-state flags (`pinned`, `cached`)
+/// stay false: they describe content this account owns a local copy policy for,
+/// which a share on someone else's volume is not.
+fn shared_entry_of(core: &Core, n: Node) -> DirEntry {
     let is_dir = n.is_folder();
     let size = match &n.kind {
         NodeKind::File {
@@ -32,6 +37,13 @@ fn shared_entry(n: Node) -> DirEntry {
         } => claimed_size.unwrap_or(*total_size_on_storage).max(0) as u64,
         NodeKind::Folder => 0,
     };
+    let role = n
+        .membership
+        .as_ref()
+        .and_then(|m| m.role_exact())
+        .map(role_to_str)
+        .unwrap_or_default()
+        .to_string();
     DirEntry {
         name: n.name,
         is_dir,
@@ -39,8 +51,9 @@ fn shared_entry(n: Node) -> DirEntry {
         modified: n.modification_time,
         pinned: false,
         cached: false,
+        path: core.rel_path_for_uid(&n.uid).unwrap_or_default(),
         uid: n.uid.to_string(),
-        path: String::new(),
+        role,
     }
 }
 
@@ -371,7 +384,10 @@ impl Core {
             .rt
             .block_on(self.client.enumerate_nodes(&uids))
             .map_err(|e| CoreError::from_api(&e, "enumerate nodes"))?;
-        Ok(nodes.into_iter().map(shared_entry).collect())
+        Ok(nodes
+            .into_iter()
+            .map(|node| shared_entry_of(self, node))
+            .collect())
     }
 
     /// List the children of a folder shared with me, addressed by uid.
@@ -393,7 +409,10 @@ impl Core {
             .rt
             .block_on(self.client.enumerate_nodes(&child_uids))
             .map_err(|e| CoreError::from_api(&e, "enumerate nodes"))?;
-        Ok(nodes.into_iter().map(shared_entry).collect())
+        Ok(nodes
+            .into_iter()
+            .map(|node| shared_entry_of(self, node))
+            .collect())
     }
 
     /// Download a file shared with me into the content cache, returning its

crates/pdfs-gui/src/app/main.rs

@@ -6,6 +6,7 @@ pub(crate) mod widgets;
 use pages::activity::*;
 use pages::browser::*;
 use pages::devices::*;
+use pages::locations::*;
 use pages::login::*;
 use pages::photo_viewer::*;
 use pages::photos::*;
@@ -49,6 +50,8 @@ use pdfs_core::control::{
     send,
 };
 
+use pdfs_core::mounts::{MountAccess, MountKind, MountMode, MountSpec};
+
 use pdfs_core::service;
 
 const APP_ID: &str = "io.narl.proton-drive-linux";
@@ -113,6 +116,7 @@ struct Ui {
     pub(crate) shared: SharedState,
     pub(crate) shared_by_me: SharedByMeState,
     pub(crate) devices: DevicesState,
+    pub(crate) locations: LocationsState,
     pub(crate) activity: ActivityState,
 }
 
@@ -333,6 +337,7 @@ fn build_window(app: &adw::Application) {
     let (shared_page, shared_widgets) = build_shared_page();
     let (shared_by_me_page, shared_by_me_widgets) = build_shared_by_me_page();
     let (devices_page, devices_widgets) = build_devices_page();
+    let (locations_page, locations_widgets) = build_locations_page();
     let (activity_page, activity_widgets) = build_activity_page();
     let (trash_page, trash_widgets) = build_trash_page();
     stack.add_named(&login_page, Some("login"));
@@ -342,6 +347,7 @@ fn build_window(app: &adw::Application) {
     stack.add_named(&shared_by_me_page, Some("sharedbyme"));
     stack.add_named(&shared_page, Some("shared"));
     stack.add_named(&devices_page, Some("devices"));
+    stack.add_named(&locations_page, Some("locations"));
     stack.add_named(&activity_page, Some("activity"));
     stack.add_named(&trash_page, Some("trash"));
 
@@ -513,6 +519,15 @@ fn build_window(app: &adw::Application) {
             inflight: Cell::new(false),
             loaded_at: Cell::new(None),
         },
+        locations: LocationsState {
+            content: locations_widgets.content.clone(),
+            status: locations_widgets.status.clone(),
+            retry: locations_widgets.retry.clone(),
+            group: locations_widgets.group.clone(),
+            rows: RefCell::new(Vec::new()),
+            inflight: Cell::new(false),
+            loaded_at: Cell::new(None),
+        },
         activity: ActivityState {
             content: activity_widgets.content.clone(),
             status: activity_widgets.status.clone(),
@@ -546,12 +561,8 @@ fn build_window(app: &adw::Application) {
     wire_trash(&ui, &trash_widgets.list, &trash_widgets.empty);
     wire_shared(&ui, &shared_widgets.retry, &shared_widgets.add_bookmark);
     wire_shared_by_me(&ui, &shared_by_me_widgets.retry);
-    wire_devices(
-        &ui,
-        &devices_widgets.retry,
-        &devices_widgets.add_folder,
-        &devices_widgets.restore,
-    );
+    wire_devices(&ui, &devices_widgets.retry, &devices_widgets.restore);
+    wire_locations(&ui, &locations_widgets.retry, &locations_widgets.add_folder);
     wire_activity(&ui, &activity_widgets.retry);
     wire_refresh(
         &ui,
@@ -562,6 +573,7 @@ fn build_window(app: &adw::Application) {
             &shared_widgets.refresh,
             &shared_by_me_widgets.refresh,
             &devices_widgets.refresh,
+            &locations_widgets.refresh,
             &activity_widgets.refresh,
         ],
     );
@@ -584,6 +596,8 @@ fn build_window(app: &adw::Application) {
             Some("shared") => load_shared(&ui_nav),
             Some("devices") if page_fresh(&ui_nav.devices.loaded_at) => {}
             Some("devices") => load_devices(&ui_nav),
+            Some("locations") if page_fresh(&ui_nav.locations.loaded_at) => {}
+            Some("locations") => load_locations(&ui_nav),
             // Activity is intentionally not TTL-cached: it changes out from under
             // the page as background uploads and edits complete, so it reloads on
             // every visit to stay live.
@@ -626,10 +640,11 @@ fn build_window(app: &adw::Application) {
 
 /// The sidebar destinations, in order: the row index is the index into this table,
 /// and each entry is `(stack page name, label, icon)`.
-const DESTINATIONS: [(&str, &str, &str); 8] = [
+const DESTINATIONS: [(&str, &str, &str); 9] = [
     ("browser", "My files", "folder-symbolic"),
     ("sharedbyme", "Shared", "emblem-shared-symbolic"),
     ("shared", "Shared with me", "system-users-symbolic"),
+    ("locations", "Locations", "drive-harddisk-symbolic"),
     ("devices", "Computers", "computer-symbolic"),
     ("gallery", "Photos", "image-x-generic-symbolic"),
     ("activity", "Activity", "document-open-recent-symbolic"),
@@ -748,6 +763,10 @@ fn reload_current_page(ui: &Rc<Ui>) {
             ui.devices.loaded_at.set(None);
             load_devices(ui);
         }
+        Some("locations") => {
+            ui.locations.loaded_at.set(None);
+            load_locations(ui);
+        }
         Some("activity") => load_activity(ui),
         _ => {}
     }

crates/pdfs-gui/src/app/pages/browser.rs

@@ -1442,6 +1442,7 @@ pub(crate) fn repaint_search(ui: &Rc<Ui>, hits: &[SearchHit]) {
             cached: false,
             uid: h.uid.clone(),
             path: h.path.clone(),
+            role: String::new(),
         })
         .collect();
     entries.sort_by(|a, b| {

crates/pdfs-gui/src/app/pages/devices.rs

@@ -9,6 +9,8 @@ pub(crate) struct DevicesState {
     pub(crate) group: adw::PreferencesGroup,
     pub(crate) rows: RefCell<Vec<gtk4::Widget>>,
     pub(crate) sync_group: adw::PreferencesGroup,
+    /// The single "This computer" summary row. The per-folder rows moved to the
+    /// Locations page, which owns every local path.
     pub(crate) sync_rows: RefCell<Vec<gtk4::Widget>>,
     /// "Rename" action in the "This computer" header. Insensitive until the
     /// device list identifies this machine's own device.
@@ -25,7 +27,8 @@ pub(crate) struct DevicesState {
 pub(crate) struct DevicesWidgets {
     pub(crate) content: gtk4::Stack,
     pub(crate) status: adw::StatusPage,
-    /// "This computer" — the local folders synced to this machine's device.
+    /// "This computer" — this machine's device identity and a pointer to its
+    /// folders on the Locations page.
     pub(crate) sync_group: adw::PreferencesGroup,
     /// "Rename" in the "This computer" header — renames this machine's device.
     pub(crate) rename_this: gtk4::Button,
@@ -33,7 +36,6 @@ pub(crate) struct DevicesWidgets {
     /// machine's own device is deliberately not among them; see
     /// [`repaint_devices`].
     pub(crate) group: adw::PreferencesGroup,
-    pub(crate) add_folder: gtk4::Button,
     /// "Restore Folders" — re-attach this device's remote folders to local
     /// directories after adopting it on a new machine.
     pub(crate) restore: gtk4::Button,
@@ -54,11 +56,6 @@ pub(crate) fn build_devices_page() -> (gtk4::Widget, DevicesWidgets) {
     titles.set_hexpand(true);
     titles.append(&title);
 
-    let add_folder = gtk4::Button::builder()
-        .label("Add Folder")
-        .valign(gtk4::Align::Center)
-        .build();
-    add_folder.add_css_class("flat");
     let restore = gtk4::Button::builder()
         .label("Restore Folders")
         .tooltip_text("Sync this computer's Drive folders back to local directories")
@@ -71,18 +68,14 @@ pub(crate) fn build_devices_page() -> (gtk4::Widget, DevicesWidgets) {
     header.append(&titles);
     header.append(&refresh);
     header.append(&restore);
-    header.append(&add_folder);
 
-    // The description spells out what the per-row On-demand switch does to the
-    // local copy, because the switch itself can't: turning it on *deletes* the
-    // files from this disk, which is not something to discover afterwards.
+    // This page is about device *identity* — which computer this is, which other
+    // computers back up to the account, and how to adopt one. The folders
+    // themselves are local paths, so they live on the Locations page; keeping a
+    // second copy of that list here would be two places to change the same mode.
     let sync_group = adw::PreferencesGroup::builder()
         .title("This computer")
-        .description(
-            "Local folders backed up to this device. Synced folders keep a full copy on \
-             this disk; on-demand folders keep the files in Proton Drive only and fetch \
-             them as you open them.",
-        )
+        .description("The device this machine backs up to.")
         .build();
     // Rename control for *this* machine's device, in the section header. The
     // current device is filtered out of "Other computers", so this is the only
@@ -145,7 +138,6 @@ pub(crate) fn build_devices_page() -> (gtk4::Widget, DevicesWidgets) {
             sync_group,
             rename_this,
             group,
-            add_folder,
             restore,
             retry,
             refresh,
@@ -153,20 +145,13 @@ pub(crate) fn build_devices_page() -> (gtk4::Widget, DevicesWidgets) {
     )
 }
 
-/// Install the Devices page's retry button and the "Add Folder" action.
-pub(crate) fn wire_devices(
-    ui: &Rc<Ui>,
-    retry: &gtk4::Button,
-    add_folder: &gtk4::Button,
-    restore: &gtk4::Button,
-) {
+/// Install the Devices page's retry button and the "Restore Folders" action.
+pub(crate) fn wire_devices(ui: &Rc<Ui>, retry: &gtk4::Button, restore: &gtk4::Button) {
     let ui_retry = ui.clone();
     retry.connect_clicked(move |_| {
         service::restart();
         load_devices(&ui_retry);
     });
-    let ui_add = ui.clone();
-    add_folder.connect_clicked(move |_| prompt_add_sync_folder(&ui_add));
     let ui_restore = ui.clone();
     restore.connect_clicked(move |_| prompt_restore_folders(&ui_restore));
     let ui_ren = ui.clone();
@@ -224,9 +209,9 @@ pub(crate) fn load_devices(ui: &Rc<Ui>) {
                 return;
             }
         };
-        // Daemon reachable: show the list and paint the synced-folders section.
+        // Daemon reachable: show the list and paint the "This computer" section.
         ui.devices.content.set_visible_child_name("list");
-        repaint_sync_folders(&ui, &folders);
+        repaint_this_computer(&ui, &folders);
 
         let devices = match devices_reply {
             Ok(Ok(Response::Devices { items })) => items,
@@ -239,35 +224,6 @@ pub(crate) fn load_devices(ui: &Rc<Ui>) {
     });
 }
 
-/// Refresh just the synced-folders section, with no status flash, no spinner and
-/// no devices round-trip. Driven by the periodic tick while the Devices page is
-/// on screen: a folder's sync progress is only live if something re-reads it.
-///
-/// A hiccup leaves the page as it is — the next tick tries again, and a real
-/// outage is reported by [`load_devices`] on the next visit.
-pub(crate) fn refresh_sync_folders(ui: &Rc<Ui>) {
-    if ui.devices.inflight.get() {
-        return;
-    }
-    ui.devices.inflight.set(true);
-    let rx = spawn_request(ui.dirs.control_socket(), Request::ListSyncFolders);
-    let ui = ui.clone();
-    glib::spawn_future_local(async move {
-        let result = rx.recv().await;
-        ui.devices.inflight.set(false);
-        let Ok(Ok(Response::SyncFolders { items })) = result else {
-            return;
-        };
-        // The page may have been navigated away from, or collapsed to a status
-        // view, while the request was in flight.
-        if ui.stack.visible_child_name().as_deref() == Some("devices")
-            && ui.devices.content.visible_child_name().as_deref() == Some("list")
-        {
-            repaint_sync_folders(&ui, &items);
-        }
-    });
-}
-
 /// The daemon didn't answer the Devices page.
 pub(crate) fn devices_unreachable(ui: &Rc<Ui>) {
     if service::is_failed() || !service::is_active() {
@@ -398,137 +354,53 @@ pub(crate) fn device_subtitle(dev: &DeviceInfo) -> String {
     }
 }
 
-/// Rebuild the "This computer" section from a fresh synced-folders listing.
-pub(crate) fn repaint_sync_folders(ui: &Rc<Ui>, folders: &[SyncFolderInfo]) {
+/// Rebuild the "This computer" section: one row naming the device this machine
+/// backs up to, and how many folders it carries.
+///
+/// The per-folder rows (mode switch, sync now, remove) live on the Locations
+/// page. They are local paths, and Locations is the one page that owns those;
+/// two lists of the same folders would be two places to flip the same switch.
+pub(crate) fn repaint_this_computer(ui: &Rc<Ui>, folders: &[SyncFolderInfo]) {
     for row in ui.devices.sync_rows.borrow_mut().drain(..) {
         ui.devices.sync_group.remove(&row);
     }
-    if folders.is_empty() {
     let row = adw::ActionRow::builder()
-            .title("No synced folders")
-            .subtitle("Add a folder to back it up to this device.")
+        .title("This computer")
+        .subtitle(this_computer_subtitle(folders))
         .build();
-        row.add_prefix(&gtk4::Image::from_icon_name("folder-symbolic"));
+    row.add_prefix(&gtk4::Image::from_icon_name("computer-symbolic"));
+    let manage = gtk4::Button::builder()
+        .label("Locations")
+        .tooltip_text("Manage this computer's folders and mountpoint")
+        .valign(gtk4::Align::Center)
+        .build();
+    manage.add_css_class("flat");
+    let ui_go = ui.clone();
+    manage.connect_clicked(move |_| ui_go.stack.set_visible_child_name("locations"));
+    row.add_suffix(&manage);
     ui.devices.sync_group.add(&row);
     *ui.devices.sync_rows.borrow_mut() = vec![row.upcast()];
-        return;
+}
+
+/// How many folders this machine backs up, and whether any of them needs
+/// attention — the one fact worth surfacing away from the folder list itself.
+pub(crate) fn this_computer_subtitle(folders: &[SyncFolderInfo]) -> String {
+    if folders.is_empty() {
+        return "No folders backed up yet — add one under Locations.".to_string();
     }
-    let mut rows: Vec<gtk4::Widget> = Vec::new();
-    for f in folders {
-        // A running pass describes itself ("Uploading photo.jpg — 12 of 40");
-        // otherwise fall back to the folder's resting state.
-        let status = match &f.progress {
-            Some(p) => sync_progress_label(p),
-            None => sync_state_label(&f.state).to_string(),
+    let count = match folders.len() {
+        1 => "1 folder backed up".to_string(),
+        n => format!("{n} folders backed up"),
     };
-        // A queued switch is where the folder is *going*, which is what the user
-        // just asked for and is waiting to see happen — so it leads the subtitle
-        // instead of the mode the folder is still technically in.
-        let subtitle = match (f.pending_mode.as_deref(), f.mode.as_str()) {
-            (Some("ondemand"), _) => format!("Going on-demand · {status}"),
-            (Some(_), _) => format!("Switching to synced · {status}"),
-            (None, "ondemand") => format!("On-demand · {status}"),
-            (None, _) => format!("Synced · {status}"),
-        };
-        let row = adw::ActionRow::builder()
-            .title(&f.local_path)
-            .subtitle(&subtitle)
-            .build();
-        row.add_prefix(&gtk4::Image::from_icon_name("folder-symbolic"));
-        let id = f.id;
-
-        // A pass that knows how far it has got shows it: the subtitle alone
-        // ("syncing photo.jpg — 12 of 40") never conveys that the end is near. This
-        // holds for scanning as much as applying — a big folder spends minutes there
-        // — but a folder syncing for the first time has no estimate to draw against
-        // (`total == 0`), and this row is repainted on the 2s tick, too slow for a
-        // pulse to read as motion. So it stays text-only until real counts exist.
-        if let Some(p) = &f.progress
-            && p.total > 0
-        {
-            let bar = gtk4::ProgressBar::builder()
-                .fraction((p.done as f64 / p.total.max(p.done) as f64).min(1.0))
-                .valign(gtk4::Align::Center)
-                .width_request(120)
-                .build();
-            row.add_suffix(&bar);
+    let attention = folders
+        .iter()
+        .filter(|f| f.state == "error" || f.state == "conflict")
+        .count();
+    match attention {
+        0 => format!("{count} · manage them under Locations"),
+        1 => format!("{count} · 1 needs attention"),
+        n => format!("{count} · {n} need attention"),
     }
-
-        // Sync now — only meaningful for mirror folders (on-demand has no local
-        // copy to reconcile). The engine also syncs on file changes and on a
-        // 120s poll; this is the "don't wait" button.
-        if f.mode != "ondemand" {
-            let sync_now = gtk4::Button::builder()
-                .icon_name("view-refresh-symbolic")
-                .tooltip_text("Sync this folder now")
-                .valign(gtk4::Align::Center)
-                .build();
-            sync_now.add_css_class("flat");
-            let ui_sync = ui.clone();
-            sync_now.connect_clicked(move |_| {
-                let rx = spawn_request(
-                    ui_sync.dirs.control_socket(),
-                    Request::SyncNow { id: Some(id) },
-                );
-                let ui_sync = ui_sync.clone();
-                glib::spawn_future_local(async move {
-                    match rx.recv().await {
-                        Ok(Ok(Response::Ok { .. })) => toast(&ui_sync, "Syncing folder…"),
-                        Ok(Ok(Response::Error { message, kind })) => {
-                            toast_failure(&ui_sync, "Couldn't sync", &message, kind)
-                        }
-                        _ => toast_error(
-                            &ui_sync,
-                            "Couldn't sync",
-                            "The mount service didn't respond.",
-                        ),
-                    }
-                });
-            });
-            row.add_suffix(&sync_now);
-        }
-
-        // On-demand toggle: off = full local copy (mirror), on = FUSE mount that
-        // frees the disk. Set the state before wiring the handler so painting the
-        // current mode doesn't fire a spurious request.
-        //
-        // A queued switch paints as already flipped: the daemon accepted the
-        // request and will act on it, so snapping the switch back to the current
-        // mode would read as "it didn't take" and invite the user to toggle again.
-        let target = f.pending_mode.as_deref().unwrap_or(&f.mode);
-        let ondemand = gtk4::Switch::builder()
-            .tooltip_text(
-                "On-demand: free this disk by keeping the files in Proton Drive only, \
-                 fetching each as you open it. Turn off to download them back and keep a \
-                 full local copy.",
-            )
-            .valign(gtk4::Align::Center)
-            .active(target == "ondemand")
-            .build();
-        let ui_mode = ui.clone();
-        ondemand.connect_state_set(move |_, on| {
-            set_sync_folder_mode(&ui_mode, id, if on { "ondemand" } else { "mirror" });
-            glib::Propagation::Proceed
-        });
-        row.add_suffix(&ondemand);
-
-        let remove = gtk4::Button::builder()
-            .icon_name("user-trash-symbolic")
-            .tooltip_text("Stop syncing this folder")
-            .valign(gtk4::Align::Center)
-            .build();
-        remove.add_css_class("flat");
-        let ui_rm = ui.clone();
-        let path = f.local_path.clone();
-        // The folder's *current* mode, not a queued one: a switch that hasn't
-        // landed yet has not moved the files anywhere.
-        let ondemand = f.mode == "ondemand";
-        remove.connect_clicked(move |_| prompt_remove_sync_folder(&ui_rm, id, &path, ondemand));
-        row.add_suffix(&remove);
-        ui.devices.sync_group.add(&row);
-        rows.push(row.upcast());
-    }
-    *ui.devices.sync_rows.borrow_mut() = rows;
 }
 
 /// Human label for a synced folder's `state` column.
@@ -592,7 +464,7 @@ pub(crate) fn prompt_add_sync_folder(ui: &Rc<Ui>) {
                     // device and creating the remote folder is off-socket network
                     // work. A fixed delay here either fires too early (empty list)
                     // or too late (row flashes in). Instead let the periodic
-                    // `refresh_sync_folders` tick pick the row up whenever it
+                    // `refresh_locations` tick pick the row up whenever it
                     // actually lands, which is what keeps a running pass live too.
                     toast(&ui, "Syncing folder…");
                 }
@@ -942,3 +814,47 @@ pub(crate) fn run_devices_mutation(
         }
     });
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    fn folder(state: &str) -> SyncFolderInfo {
+        SyncFolderInfo {
+            id: 1,
+            local_path: "/home/u/Documents".into(),
+            remote_uid: "vol~link".into(),
+            mode: "mirror".into(),
+            state: state.into(),
+            last_sync: 0,
+            pending_mode: None,
+            progress: None,
+        }
+    }
+
+    #[test]
+    fn a_machine_with_no_folders_is_told_where_to_add_one() {
+        assert_eq!(
+            this_computer_subtitle(&[]),
+            "No folders backed up yet — add one under Locations."
+        );
+    }
+
+    #[test]
+    fn folders_needing_attention_are_counted_not_hidden() {
+        // The per-folder rows moved to Locations, so this row is the only place
+        // the Computers page can surface that something is wrong.
+        assert_eq!(
+            this_computer_subtitle(&[folder("idle"), folder("idle")]),
+            "2 folders backed up · manage them under Locations"
+        );
+        assert_eq!(
+            this_computer_subtitle(&[folder("idle"), folder("error")]),
+            "2 folders backed up · 1 needs attention"
+        );
+        assert_eq!(
+            this_computer_subtitle(&[folder("conflict"), folder("error")]),
+            "2 folders backed up · 2 need attention"
+        );
+    }
+}

crates/pdfs-gui/src/app/pages/locations.rs

@@ -0,0 +1,536 @@
+//! The Locations page: every local place Proton Drive occupies on this machine.
+//!
+//! One row per [`MountSpec`] from [`Request::ListLocations`] — the primary
+//! `~/ProtonDrive` mount, plus each folder this computer backs up, whether it is
+//! a mirrored local directory or an on-demand FUSE session. The page is called
+//! *Locations* rather than *Mounts* because a mirror folder is a plain directory
+//! with no FUSE session behind it (mount-architecture.md §4).
+//!
+//! The device rows drive the same control requests the Computers page used to:
+//! mode switch, sync now, remove. What is new here is that the primary mount is
+//! listed alongside them, with the mountpoint chooser that used to live in
+//! Settings.
+
+use crate::*;
+
+pub(crate) struct LocationsState {
+    pub(crate) content: gtk4::Stack,
+    pub(crate) status: adw::StatusPage,
+    pub(crate) retry: gtk4::Button,
+    pub(crate) group: adw::PreferencesGroup,
+    pub(crate) rows: RefCell<Vec<gtk4::Widget>>,
+    pub(crate) inflight: Cell<bool>,
+    pub(crate) loaded_at: Cell<Option<Instant>>,
+}
+
+/// Widgets the Locations page's load/repaint touch.
+pub(crate) struct LocationsWidgets {
+    pub(crate) content: gtk4::Stack,
+    pub(crate) status: adw::StatusPage,
+    pub(crate) group: adw::PreferencesGroup,
+    pub(crate) retry: gtk4::Button,
+    pub(crate) refresh: gtk4::Button,
+    pub(crate) add_folder: gtk4::Button,
+}
+
+pub(crate) fn build_locations_page() -> (gtk4::Widget, LocationsWidgets) {
+    let title = gtk4::Label::builder()
+        .label("Locations")
+        .halign(gtk4::Align::Start)
+        .build();
+    title.add_css_class("title-2");
+
+    let add_folder = gtk4::Button::builder()
+        .label("Add Folder")
+        .tooltip_text("Back a local folder up to this computer's Proton Drive device")
+        .valign(gtk4::Align::Center)
+        .build();
+    add_folder.add_css_class("flat");
+    let refresh = refresh_button();
+
+    let header = gtk4::Box::new(gtk4::Orientation::Horizontal, 8);
+    let titles = gtk4::Box::new(gtk4::Orientation::Vertical, 2);
+    titles.set_hexpand(true);
+    titles.append(&title);
+    header.append(&titles);
+    header.append(&refresh);
+    header.append(&add_folder);
+    // Clamped to the same width as the rows below, or the page title floats off
+    // to the left of the list it names.
+    let header_clamp = adw::Clamp::builder().child(&header).build();
+
+    // Same warning the Computers page carried, for the same reason: the
+    // on-demand switch removes the local copy, which is not a thing to discover
+    // after the fact.
+    let group = adw::PreferencesGroup::builder()
+        .title("On this computer")
+        .description(
+            "Where Proton Drive lives on this machine. Synced folders keep a full copy on \
+             this disk; on-demand folders keep the files in Proton Drive only and fetch \
+             them as you open them.",
+        )
+        .build();
+
+    let groups = gtk4::Box::new(gtk4::Orientation::Vertical, 18);
+    groups.append(&group);
+    let clamp = adw::Clamp::builder().child(&groups).build();
+    // Never scroll sideways: a location's title is a full path, and letting the
+    // row grow to fit one pushes the controls at its end off screen. Constrained,
+    // the path ellipsizes and the switch/remove/open stay reachable.
+    let scroll = gtk4::ScrolledWindow::builder()
+        .vexpand(true)
+        .hscrollbar_policy(gtk4::PolicyType::Never)
+        .child(&clamp)
+        .build();
+
+    let retry = gtk4::Button::builder()
+        .label("Retry")
+        .halign(gtk4::Align::Center)
+        .build();
+    retry.add_css_class("pill");
+    retry.add_css_class("suggested-action");
+    retry.set_visible(false);
+    let status = adw::StatusPage::builder()
+        .icon_name("drive-harddisk-symbolic")
+        .title("Loading…")
+        .child(&retry)
+        .build();
+    // A bare `StatusPage` asks for more width than a half-screen window has, and
+    // a `Stack` is as wide as its widest child — so an unwrapped status page
+    // silently widens the *list* page too, pushing each row's controls off the
+    // right edge. Scrolling it (never horizontally) caps that demand.
+    let status_scroll = gtk4::ScrolledWindow::builder()
+        .vexpand(true)
+        .hscrollbar_policy(gtk4::PolicyType::Never)
+        .child(&status)
+        .build();
+
+    let content = gtk4::Stack::new();
+    content.add_named(&scroll, Some("list"));
+    content.add_named(&status_scroll, Some("status"));
+
+    let page = gtk4::Box::new(gtk4::Orientation::Vertical, 12);
+    page.set_margin_top(18);
+    page.set_margin_bottom(18);
+    page.set_margin_start(18);
+    page.set_margin_end(18);
+    page.append(&header_clamp);
+    page.append(&content);
+
+    let widgets = LocationsWidgets {
+        content: content.clone(),
+        status: status.clone(),
+        group: group.clone(),
+        retry: retry.clone(),
+        refresh,
+        add_folder,
+    };
+    (page.upcast(), widgets)
+}
+
+pub(crate) fn wire_locations(ui: &Rc<Ui>, retry: &gtk4::Button, add_folder: &gtk4::Button) {
+    let ui_retry = ui.clone();
+    retry.connect_clicked(move |_| {
+        ui_retry.locations.loaded_at.set(None);
+        load_locations(&ui_retry);
+    });
+    let ui_add = ui.clone();
+    add_folder.connect_clicked(move |_| prompt_add_sync_folder(&ui_add));
+}
+
+/// Show a status page in place of the locations list.
+pub(crate) fn locations_status(
+    ui: &Rc<Ui>,
+    icon: &str,
+    title: &str,
+    description: &str,
+    retry: bool,
+) {
+    ui.locations.status.set_icon_name(Some(icon));
+    ui.locations.status.set_title(title);
+    ui.locations.status.set_description(Some(description));
+    ui.locations.retry.set_visible(retry);
+    ui.locations.content.set_visible_child_name("status");
+}
+
+/// Fetch every local location and repaint the list.
+pub(crate) fn load_locations(ui: &Rc<Ui>) {
+    if ui.locations.inflight.get() {
+        return;
+    }
+    ui.locations.inflight.set(true);
+    locations_status(
+        ui,
+        "drive-harddisk-symbolic",
+        "Loading…",
+        "Reading this computer's Proton Drive locations.",
+        false,
+    );
+    ui.busy_begin();
+    let rx = spawn_request(ui.dirs.control_socket(), Request::ListLocations);
+    let ui = ui.clone();
+    glib::spawn_future_local(async move {
+        let result = rx.recv().await;
+        ui.busy_end();
+        ui.locations.inflight.set(false);
+        match result {
+            Ok(Ok(Response::Locations { items })) => {
+                ui.locations.content.set_visible_child_name("list");
+                repaint_locations(&ui, &items);
+                ui.locations.loaded_at.set(Some(Instant::now()));
+            }
+            Ok(Ok(Response::Error { message, .. })) => {
+                ui.locations.loaded_at.set(None);
+                locations_status(
+                    &ui,
+                    "dialog-warning-symbolic",
+                    "Unavailable",
+                    &message,
+                    true,
+                );
+            }
+            _ => {
+                ui.locations.loaded_at.set(None);
+                locations_unreachable(&ui);
+            }
+        }
+    });
+}
+
+/// Refresh the rows with no status flash and no spinner, from the periodic tick:
+/// a sync pass's progress is only live if something re-reads it.
+pub(crate) fn refresh_locations(ui: &Rc<Ui>) {
+    if ui.locations.inflight.get() {
+        return;
+    }
+    ui.locations.inflight.set(true);
+    let rx = spawn_request(ui.dirs.control_socket(), Request::ListLocations);
+    let ui = ui.clone();
+    glib::spawn_future_local(async move {
+        let result = rx.recv().await;
+        ui.locations.inflight.set(false);
+        let Ok(Ok(Response::Locations { items })) = result else {
+            return;
+        };
+        // The page may have been navigated away from, or collapsed to a status
+        // view, while the request was in flight.
+        if ui.stack.visible_child_name().as_deref() == Some("locations")
+            && ui.locations.content.visible_child_name().as_deref() == Some("list")
+        {
+            repaint_locations(&ui, &items);
+        }
+    });
+}
+
+/// The daemon didn't answer the Locations page.
+pub(crate) fn locations_unreachable(ui: &Rc<Ui>) {
+    if service::is_failed() || !service::is_active() {
+        locations_status(
+            ui,
+            "network-offline-symbolic",
+            "Not connected",
+            "The Proton Drive mount service isn't running.",
+            true,
+        );
+        return;
+    }
+    locations_status(
+        ui,
+        "folder-remote-symbolic",
+        "Connecting…",
+        "Waiting for the Proton Drive mount service to come up.",
+        false,
+    );
+    let ui = ui.clone();
+    glib::timeout_add_local_once(CONNECT_RETRY_INTERVAL, move || {
+        if ui.stack.visible_child_name().as_deref() == Some("locations") {
+            load_locations(&ui);
+        }
+    });
+}
+
+pub(crate) fn repaint_locations(ui: &Rc<Ui>, items: &[MountSpec]) {
+    for row in ui.locations.rows.borrow_mut().drain(..) {
+        ui.locations.group.remove(&row);
+    }
+    if items.is_empty() {
+        let row = adw::ActionRow::builder()
+            .title("No locations")
+            .subtitle("The mount service hasn't reported a mountpoint yet.")
+            .build();
+        row.add_prefix(&gtk4::Image::from_icon_name("drive-harddisk-symbolic"));
+        ui.locations.group.add(&row);
+        *ui.locations.rows.borrow_mut() = vec![row.upcast()];
+        return;
+    }
+
+    let mut rows: Vec<gtk4::Widget> = Vec::new();
+    for spec in items {
+        let row = adw::ActionRow::builder()
+            .title(&spec.local_path)
+            .subtitle(location_subtitle(spec))
+            // One line each: a wrapped path would reflow the whole list every
+            // time a sync state changed under it.
+            .title_lines(1)
+            .subtitle_lines(1)
+            .build();
+        row.add_prefix(&gtk4::Image::from_icon_name(location_icon(&spec.kind)));
+
+        // A read-only location cannot be written through even where the files are
+        // visible; saying so on the row is cheaper than letting the user find out
+        // from a save dialog.
+        if spec.access == MountAccess::Ro {
+            let badge = gtk4::Label::new(Some("Read-only"));
+            badge.add_css_class("dim-label");
+            badge.add_css_class("caption");
+            badge.set_valign(gtk4::Align::Center);
+            row.add_suffix(&badge);
+        }
+
+        // Same rule as the Computers page: a first pass has no estimate to draw
+        // against, so the bar appears only once real counts exist.
+        if let Some(p) = &spec.progress
+            && p.total > 0
+        {
+            let bar = gtk4::ProgressBar::builder()
+                .fraction((p.done as f64 / p.total.max(p.done) as f64).min(1.0))
+                .valign(gtk4::Align::Center)
+                .width_request(120)
+                .build();
+            row.add_suffix(&bar);
+        }
+
+        match &spec.kind {
+            MountKind::MyFiles => add_my_files_controls(ui, &row),
+            MountKind::Device { sync_folder_id } => {
+                add_device_controls(ui, &row, spec, *sync_folder_id)
+            }
+            // A standalone shared mount has no local mode to switch and is not
+            // this device's to remove.
+            MountKind::Shared { .. } => {}
+        }
+
+        let open = gtk4::Button::builder()
+            .icon_name("folder-open-symbolic")
+            .tooltip_text("Open this folder")
+            .valign(gtk4::Align::Center)
+            .build();
+        open.add_css_class("flat");
+        let path = spec.local_path.clone();
+        open.connect_clicked(move |_| open_path(&path));
+        row.add_suffix(&open);
+
+        ui.locations.group.add(&row);
+        rows.push(row.upcast());
+    }
+    *ui.locations.rows.borrow_mut() = rows;
+}
+
+/// The primary mount's only control: where it lives. Changing it rewrites config
+/// and offers a service restart, which is why it stays a single prompt shared
+/// with the (now removed) Settings row.
+fn add_my_files_controls(ui: &Rc<Ui>, row: &adw::ActionRow) {
+    let change = gtk4::Button::builder()
+        .label("Change")
+        .tooltip_text("Choose a different folder for the Proton Drive mount")
+        .valign(gtk4::Align::Center)
+        .build();
+    change.add_css_class("flat");
+    let ui_mp = ui.clone();
+    change.connect_clicked(move |_| prompt_mountpoint(&ui_mp));
+    row.add_suffix(&change);
+}
+
+/// Sync now (mirror only), the on-demand switch, and Remove — the same three
+/// controls, and the same handlers, the Computers page used to carry.
+fn add_device_controls(ui: &Rc<Ui>, row: &adw::ActionRow, spec: &MountSpec, id: i64) {
+    if spec.mode != MountMode::OnDemand {
+        let sync_now = gtk4::Button::builder()
+            .icon_name("view-refresh-symbolic")
+            .tooltip_text("Sync this folder now")
+            .valign(gtk4::Align::Center)
+            .build();
+        sync_now.add_css_class("flat");
+        let ui_sync = ui.clone();
+        sync_now.connect_clicked(move |_| sync_folder_now(&ui_sync, id));
+        row.add_suffix(&sync_now);
+    }
+
+    // A queued switch paints as already flipped: the daemon accepted it and will
+    // act on it, so snapping back would read as "it didn't take". The state is
+    // set before the handler is wired so painting the current mode doesn't fire
+    // a spurious request.
+    let target = spec.pending_mode.unwrap_or(spec.mode);
+    let ondemand = gtk4::Switch::builder()
+        .tooltip_text(
+            "On-demand: free this disk by keeping the files in Proton Drive only, \
+             fetching each as you open it. Turn off to download them back and keep a \
+             full local copy.",
+        )
+        .valign(gtk4::Align::Center)
+        .active(target == MountMode::OnDemand)
+        .build();
+    let ui_mode = ui.clone();
+    ondemand.connect_state_set(move |_, on| {
+        set_sync_folder_mode(&ui_mode, id, if on { "ondemand" } else { "mirror" });
+        glib::Propagation::Proceed
+    });
+    row.add_suffix(&ondemand);
+
+    let remove = gtk4::Button::builder()
+        .icon_name("user-trash-symbolic")
+        .tooltip_text("Stop syncing this folder")
+        .valign(gtk4::Align::Center)
+        .build();
+    remove.add_css_class("flat");
+    let ui_rm = ui.clone();
+    let path = spec.local_path.clone();
+    // The folder's *current* mode, not a queued one: a switch that hasn't landed
+    // yet has not moved the files anywhere.
+    let is_ondemand = spec.mode == MountMode::OnDemand;
+    remove.connect_clicked(move |_| prompt_remove_sync_folder(&ui_rm, id, &path, is_ondemand));
+    row.add_suffix(&remove);
+}
+
+/// Ask the daemon for an immediate pass over one folder.
+fn sync_folder_now(ui: &Rc<Ui>, id: i64) {
+    let rx = spawn_request(ui.dirs.control_socket(), Request::SyncNow { id: Some(id) });
+    let ui = ui.clone();
+    glib::spawn_future_local(async move {
+        match rx.recv().await {
+            Ok(Ok(Response::Ok { .. })) => toast(&ui, "Syncing folder…"),
+            Ok(Ok(Response::Error { message, kind })) => {
+                toast_failure(&ui, "Couldn't sync", &message, kind)
+            }
+            _ => toast_error(&ui, "Couldn't sync", "The mount service didn't respond."),
+        }
+    });
+}
+
+pub(crate) fn location_icon(kind: &MountKind) -> &'static str {
+    match kind {
+        MountKind::MyFiles => "folder-remote-symbolic",
+        MountKind::Device { .. } => "folder-symbolic",
+        MountKind::Shared { .. } => "system-users-symbolic",
+    }
+}
+
+/// One line describing what a location *is* and what it is doing.
+///
+/// Ordered by how likely it is to be what the user came to check: a queued mode
+/// switch leads (they just asked for it), then the resting mode, then the sync
+/// state, then — only when it is surprising — the fact that no session owns the
+/// path. A mirror folder is a plain directory with no FUSE session, so "not
+/// mounted" is its normal state and saying it would be noise.
+pub(crate) fn location_subtitle(spec: &MountSpec) -> String {
+    let mut parts: Vec<String> = Vec::new();
+    match &spec.kind {
+        MountKind::MyFiles => parts.push("My files".to_string()),
+        MountKind::Shared { .. } => parts.push("Shared folder".to_string()),
+        MountKind::Device { .. } => match (spec.pending_mode, spec.mode) {
+            (Some(MountMode::OnDemand), _) => parts.push("Going on-demand".to_string()),
+            (Some(MountMode::Mirror), _) => parts.push("Switching to synced".to_string()),
+            (Some(MountMode::Unknown) | None, MountMode::OnDemand) => {
+                parts.push("On-demand".to_string())
+            }
+            (Some(MountMode::Unknown) | None, _) => parts.push("Synced".to_string()),
+        },
+    }
+    if matches!(spec.kind, MountKind::Device { .. }) {
+        parts.push(match &spec.progress {
+            Some(p) => sync_progress_label(p),
+            None => sync_state_label(&spec.state).to_string(),
+        });
+    }
+    // Only the locations that are supposed to have a session report its absence:
+    // a mirror folder never has one.
+    let expects_session = !matches!(spec.kind, MountKind::Device { .. })
+        || spec.mode == MountMode::OnDemand
+        || spec.pending_mode == Some(MountMode::OnDemand);
+    if expects_session && !spec.mounted {
+        parts.push("not mounted".to_string());
+    }
+    parts.join(" · ")
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    fn spec(kind: MountKind, mode: MountMode, mounted: bool) -> MountSpec {
+        MountSpec {
+            id: 1,
+            kind,
+            local_path: "/home/u/ProtonDrive".into(),
+            root_uid: "vol~link".into(),
+            root_share_id: "share".into(),
+            mode,
+            access: MountAccess::Rw,
+            state: "idle".into(),
+            last_sync: 0,
+            pending_mode: None,
+            mounted,
+            progress: None,
+        }
+    }
+
+    #[test]
+    fn a_mirror_folder_is_never_reported_as_unmounted() {
+        // It is a plain local directory: no FUSE session is expected, so saying
+        // "not mounted" would describe every healthy mirror folder as broken.
+        let spec = spec(
+            MountKind::Device { sync_folder_id: 7 },
+            MountMode::Mirror,
+            false,
+        );
+        assert_eq!(location_subtitle(&spec), "Synced · up to date");
+    }
+
+    #[test]
+    fn an_on_demand_folder_without_a_session_says_so() {
+        let spec = spec(
+            MountKind::Device { sync_folder_id: 7 },
+            MountMode::OnDemand,
+            false,
+        );
+        assert_eq!(
+            location_subtitle(&spec),
+            "On-demand · up to date · not mounted"
+        );
+    }
+
+    #[test]
+    fn a_queued_switch_leads_the_subtitle() {
+        let mut spec = spec(
+            MountKind::Device { sync_folder_id: 7 },
+            MountMode::Mirror,
+            true,
+        );
+        spec.pending_mode = Some(MountMode::OnDemand);
+        assert!(location_subtitle(&spec).starts_with("Going on-demand"));
+        spec.mode = MountMode::OnDemand;
+        spec.pending_mode = Some(MountMode::Mirror);
+        assert!(location_subtitle(&spec).starts_with("Switching to synced"));
+    }
+
+    /// An unrecognised persisted mode must not silently read as "Synced" *and*
+    /// must not lose the rest of the line.
+    #[test]
+    fn the_primary_mount_reports_only_its_own_facts() {
+        let mut spec = spec(MountKind::MyFiles, MountMode::OnDemand, true);
+        assert_eq!(location_subtitle(&spec), "My files");
+        spec.mounted = false;
+        assert_eq!(location_subtitle(&spec), "My files · not mounted");
+    }
+
+    #[test]
+    fn sync_state_reaches_the_subtitle() {
+        let mut spec = spec(
+            MountKind::Device { sync_folder_id: 2 },
+            MountMode::Mirror,
+            true,
+        );
+        spec.state = "conflict".into();
+        assert_eq!(location_subtitle(&spec), "Synced · needs attention");
+    }
+}

crates/pdfs-gui/src/app/pages/mod.rs

@@ -1,6 +1,7 @@
 pub(crate) mod activity;
 pub(crate) mod browser;
 pub(crate) mod devices;
+pub(crate) mod locations;
 pub(crate) mod login;
 pub(crate) mod photo_viewer;
 pub(crate) mod photos;

crates/pdfs-gui/src/app/pages/shared.rs

@@ -298,8 +298,15 @@ fn shared_entry_row(ui: &Rc<Ui>, entry: &DirEntry) -> adw::ActionRow {
         .title(&entry.name)
         .activatable(true)
         .build();
-    if !entry.is_dir {
-        row.set_subtitle(&human_bytes(entry.size));
+    let subtitle = shared_row_subtitle(entry);
+    if !subtitle.is_empty() {
+        row.set_subtitle(&subtitle);
+    }
+    // What I am allowed to do with someone else's file is the thing this page
+    // cannot leave implicit: a viewer share is browsable and unwritable, and
+    // that is only visible if it is said.
+    if let Some(badge) = role_badge(&entry.role) {
+        row.add_suffix(&badge);
     }
     row.add_prefix(&gtk4::Image::from_icon_name(if entry.is_dir {
         "folder-symbolic"
@@ -325,6 +332,43 @@ fn shared_entry_row(ui: &Rc<Ui>, entry: &DirEntry) -> adw::ActionRow {
     row
 }
 
+/// A shared row's subtitle: its size (files only), and where it can be reached
+/// in the local mount once the synthetic `Shared with me/` directory has interned
+/// it. An unlisted share has no local path yet, and says nothing rather than
+/// pointing at a directory that is not there.
+pub(crate) fn shared_row_subtitle(entry: &DirEntry) -> String {
+    let mut parts: Vec<String> = Vec::new();
+    if !entry.is_dir {
+        parts.push(human_bytes(entry.size));
+    }
+    if !entry.path.is_empty() {
+        parts.push(format!("in {}", entry.path));
+    }
+    parts.join(" · ")
+}
+
+/// The display name for a wire role, or `None` when there is nothing to show:
+/// owned content carries no role, and a role the API did not report is not
+/// guessed at (the SDK's `from_permissions_exact` returns `None` for an
+/// unrecognised mask rather than degrading it to viewer).
+pub(crate) fn role_label(role: &str) -> Option<&'static str> {
+    match role {
+        "viewer" => Some("Viewer"),
+        "editor" => Some("Editor"),
+        "admin" => Some("Admin"),
+        _ => None,
+    }
+}
+
+/// A dim role pill for a share I did not create.
+pub(crate) fn role_badge(role: &str) -> Option<gtk4::Label> {
+    let badge = gtk4::Label::new(Some(role_label(role)?));
+    badge.add_css_class("dim-label");
+    badge.add_css_class("caption");
+    badge.set_valign(gtk4::Align::Center);
+    Some(badge)
+}
+
 /// Download a file shared with me into the daemon's cache and hand it to the
 /// user's default application — the shared-item twin of the browser's
 /// download-and-open, addressed by uid because the file lives outside the mount.
@@ -663,3 +707,52 @@ pub(crate) fn run_shared_mutation(
         }
     });
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    fn entry(is_dir: bool, path: &str, role: &str) -> DirEntry {
+        DirEntry {
+            name: "Budget.ods".into(),
+            is_dir,
+            size: 2048,
+            modified: 0,
+            pinned: false,
+            cached: false,
+            uid: "vol~link".into(),
+            path: path.into(),
+            role: role.into(),
+        }
+    }
+
+    #[test]
+    fn a_share_with_no_local_path_says_nothing_about_one() {
+        // Before the synthetic directory has been listed, the daemon cannot
+        // resolve a path — pointing at one that isn't there would be worse than
+        // silence.
+        assert_eq!(shared_row_subtitle(&entry(true, "", "viewer")), "");
+        assert_eq!(
+            shared_row_subtitle(&entry(false, "", "viewer")),
+            human_bytes(2048)
+        );
+    }
+
+    #[test]
+    fn a_resident_share_reports_where_it_can_be_reached() {
+        let subtitle = shared_row_subtitle(&entry(true, "Shared with me/Team Budget", "editor"));
+        assert_eq!(subtitle, "in Shared with me/Team Budget");
+    }
+
+    #[test]
+    fn only_a_known_role_becomes_a_badge() {
+        // "" is owned content (no role applies) and an unrecognised mask is
+        // deliberately not guessed at — `from_permissions_exact` returns None
+        // rather than degrading to viewer, and this must not undo that.
+        for role in ["viewer", "editor", "admin"] {
+            assert!(role_label(role).is_some(), "{role} should have a label");
+        }
+        assert!(role_label("").is_none());
+        assert!(role_label("inherited").is_none());
+    }
+}

crates/pdfs-gui/src/app/pages/shared_by_me.rs

@@ -236,9 +236,9 @@ pub(crate) fn repaint_shared_by_me(ui: &Rc<Ui>, items: &[SharedItem]) {
             row.add_suffix(&open);
         }
 
-        // Manage opens the per-node Share dialog — only when the node's path is
-        // known (it has been browsed to this session); the dialog is path-keyed.
-        if !item.path.is_empty() {
+        // Manage opens the per-node Share dialog. It used to be offered only for
+        // an item whose path the daemon could resolve; the dialog now addresses a
+        // pathless node by uid, so every shared item can be managed from here.
         let manage = gtk4::Button::builder()
             .label("Manage")
             .valign(gtk4::Align::Center)
@@ -248,7 +248,6 @@ pub(crate) fn repaint_shared_by_me(ui: &Rc<Ui>, items: &[SharedItem]) {
         let entry = shared_item_as_entry(item);
         manage.connect_clicked(move |_| open_share_dialog(&ui_manage, &entry));
         row.add_suffix(&manage);
-        }
 
         ui.shared_by_me.group.add(&row);
         rows.push(row.upcast());
@@ -295,5 +294,7 @@ pub(crate) fn shared_item_as_entry(item: &SharedItem) -> DirEntry {
         cached: false,
         uid: item.uid.clone(),
         path: item.path.clone(),
+        // Shared *by* me: I own it, so there is no role of mine to report.
+        role: String::new(),
     }
 }

crates/pdfs-gui/src/app/pages/status.rs

@@ -31,8 +31,8 @@ pub(crate) struct StatusState {
     /// Cache-budget editor (GiB). Populated once from config; user edits drive a
     /// `SetCacheBudget` round-trip. Guarded by [`Self::settings_suppress`].
     pub(crate) budget_row: adw::SpinRow,
-    /// Shows the active mountpoint in its subtitle; updated when the user picks a
-    /// new folder.
+    /// Shows where the primary mount lives; the folder itself is managed on the
+    /// Locations page, which owns every local path.
     pub(crate) mountpoint_row: adw::ActionRow,
     /// Set while a settings widget is being populated programmatically, so its
     /// change handler skips the IPC/systemd side effect.
@@ -100,7 +100,8 @@ pub(crate) struct MainWidgets {
     pub(crate) budget_row: adw::SpinRow,
     /// Purges all unpinned cached content.
     pub(crate) purge_button: gtk4::Button,
-    /// Shows the active mountpoint; its suffix button opens a folder chooser.
+    /// Shows the active mountpoint; its suffix button opens the Locations page,
+    /// which is where the folder is changed.
     pub(crate) mountpoint_row: adw::ActionRow,
     pub(crate) mountpoint_button: gtk4::Button,
 }
@@ -215,12 +216,17 @@ pub(crate) fn build_main_page() -> (gtk4::Widget, MainWidgets) {
         .subtitle("Mount Proton Drive automatically when you log in.")
         .build();
     system_group.add(&autostart_row);
+    // The mountpoint is a *location*, and every other local path this client
+    // owns is managed on the Locations page. Keeping a second chooser here would
+    // be a second source of truth for the same setting, so this row reports the
+    // path and hands the change over.
     let mountpoint_row = adw::ActionRow::builder()
         .title("Mountpoint")
         .subtitle("—")
         .build();
     let mountpoint_button = gtk4::Button::builder()
-        .label("Change")
+        .label("Locations")
+        .tooltip_text("Manage this computer's Proton Drive locations")
         .valign(gtk4::Align::Center)
         .build();
     mountpoint_button.add_css_class("flat");
@@ -372,10 +378,10 @@ pub(crate) fn wire_settings(
         }
     });
 
-    // Mountpoint: pick a folder, persist it, and offer to restart the mount so
-    // the change takes effect (the daemon reads the path on mount).
+    // Mountpoint: the chooser lives on the Locations page, next to every other
+    // local path; this button is the way there.
     let ui_mp = ui.clone();
-    mountpoint_button.connect_clicked(move |_| prompt_mountpoint(&ui_mp));
+    mountpoint_button.connect_clicked(move |_| ui_mp.stack.set_visible_child_name("locations"));
 }
 
 /// Run a settings control-socket round-trip (budget / purge) on a worker thread,
@@ -423,6 +429,12 @@ pub(crate) fn prompt_mountpoint(ui: &Rc<Ui>) {
             return;
         }
         ui.status.mountpoint_row.set_subtitle(&path_str);
+        // The Locations page shows the same path as a row title; its cached rows
+        // are now stale whether or not it is the visible page.
+        ui.locations.loaded_at.set(None);
+        if ui.stack.visible_child_name().as_deref() == Some("locations") {
+            load_locations(&ui);
+        }
 
         // The daemon only reads the mountpoint at mount time, so offer a restart.
         let confirm = adw::AlertDialog::builder()
@@ -503,7 +515,7 @@ pub(crate) fn refresh(ui: &Rc<Ui>) {
     // they are on screen. Every other page loads on navigation only.
     match ui.stack.visible_child_name().as_deref() {
         Some("main") => refresh_quota(ui),
-        Some("devices") => refresh_sync_folders(ui),
+        Some("locations") => refresh_locations(ui),
         Some("activity") => refresh_activity(ui),
         _ => {}
     }

crates/pdfs-gui/src/app/widgets/share_dialog.rs

@@ -21,13 +21,117 @@ pub(crate) fn role_wire_to_index(role: &str) -> u32 {
     }
 }
 
+/// How an open Share dialog addresses its node.
+///
+/// A node the browser is showing has a mountpoint-relative path. A node reached
+/// from Shared or Shared-with-me may not: it can live under a device folder's
+/// own inode space, or on someone else's volume, neither of which the primary
+/// mount's path space can name. Those carry a uid instead, and the daemon
+/// resolves it with `Core::resolve_anywhere` (mount-architecture.md P4).
+///
+/// The two are separate request variants rather than one request with an
+/// optional field on purpose: an older daemon that ignored `uid` would resolve
+/// the empty path to the *mount root* and act on the wrong node.
+pub(crate) enum ShareTarget {
+    Path(String),
+    Uid(String),
+}
+
+impl ShareTarget {
+    fn list(&self) -> Request {
+        match self {
+            ShareTarget::Path(path) => Request::ListShare { path: path.clone() },
+            ShareTarget::Uid(uid) => Request::ListShareByUid { uid: uid.clone() },
+        }
+    }
+
+    fn invite(&self, emails: Vec<String>, role: String, message: Option<String>) -> Request {
+        match self {
+            ShareTarget::Path(path) => Request::ShareNode {
+                path: path.clone(),
+                emails,
+                role,
+                message,
+            },
+            ShareTarget::Uid(uid) => Request::ShareNodeByUid {
+                uid: uid.clone(),
+                emails,
+                role,
+                message,
+            },
+        }
+    }
+
+    fn update_role(&self, id: String, kind: ShareEntryKind, role: String) -> Request {
+        match self {
+            ShareTarget::Path(path) => Request::UpdateShareRole {
+                path: path.clone(),
+                id,
+                kind,
+                role,
+            },
+            ShareTarget::Uid(uid) => Request::UpdateShareRoleByUid {
+                uid: uid.clone(),
+                id,
+                kind,
+                role,
+            },
+        }
+    }
+
+    fn remove_entry(&self, id: String, kind: ShareEntryKind) -> Request {
+        match self {
+            ShareTarget::Path(path) => Request::RemoveShareEntry {
+                path: path.clone(),
+                id,
+                kind,
+            },
+            ShareTarget::Uid(uid) => Request::RemoveShareEntryByUid {
+                uid: uid.clone(),
+                id,
+                kind,
+            },
+        }
+    }
+
+    fn create_link(&self, role: String, password: Option<String>) -> Request {
+        match self {
+            ShareTarget::Path(path) => Request::CreatePublicLink {
+                path: path.clone(),
+                role,
+                password,
+                expires: None,
+            },
+            ShareTarget::Uid(uid) => Request::CreatePublicLinkByUid {
+                uid: uid.clone(),
+                role,
+                password,
+                expires: None,
+            },
+        }
+    }
+
+    fn remove_link(&self, id: String) -> Request {
+        match self {
+            ShareTarget::Path(path) => Request::RemovePublicLink {
+                path: path.clone(),
+                id,
+            },
+            ShareTarget::Uid(uid) => Request::RemovePublicLinkByUid {
+                uid: uid.clone(),
+                id,
+            },
+        }
+    }
+}
+
 /// The mutable state behind an open Share dialog, so the invite/role/link
 /// handlers can rebuild the people and link sections after each change without
 /// tearing the whole dialog down.
 pub(crate) struct ShareDialog {
     pub(crate) ui: Rc<Ui>,
-    /// The node's mountpoint-relative path — how every request addresses it.
-    pub(crate) rel: String,
+    /// How every request from this dialog addresses the node.
+    pub(crate) target: ShareTarget,
     pub(crate) people: adw::PreferencesGroup,
     pub(crate) link_group: adw::PreferencesGroup,
     pub(crate) people_rows: RefCell<Vec<gtk4::Widget>>,
@@ -41,7 +145,13 @@ pub(crate) fn open_share_dialog(ui: &Rc<Ui>, entry: &DirEntry) {
         toast_error(ui, "Can't share", "Proton Drive isn't connected.");
         return;
     }
-    let rel = entry_rel(ui, entry);
+    // A node with no path is not a bug here: Shared and Shared-with-me list
+    // nodes that the primary mount never interned. Address those by uid.
+    let target = if entry.path.is_empty() {
+        ShareTarget::Uid(entry.uid.clone())
+    } else {
+        ShareTarget::Path(entry_rel(ui, entry))
+    };
 
     let toolbar = adw::ToolbarView::new();
     let header = adw::HeaderBar::new();
@@ -110,7 +220,7 @@ pub(crate) fn open_share_dialog(ui: &Rc<Ui>, entry: &DirEntry) {
 
     let state = Rc::new(ShareDialog {
         ui: ui.clone(),
-        rel,
+        target,
         people,
         link_group,
         people_rows: RefCell::new(Vec::new()),
@@ -144,12 +254,7 @@ pub(crate) fn open_share_dialog(ui: &Rc<Ui>, entry: &DirEntry) {
         let msg_clear = message_row.clone();
         share_dialog_op(
             &state_inv,
-            Request::ShareNode {
-                path: state_inv.rel.clone(),
-                emails,
-                role,
-                message,
-            },
+            state_inv.target.invite(emails, role, message),
             "Invitations sent",
             "Couldn't send invitations",
             Some(Box::new(move || {
@@ -165,12 +270,7 @@ pub(crate) fn open_share_dialog(ui: &Rc<Ui>, entry: &DirEntry) {
 
 /// Re-fetch the node's share and rebuild the people + public-link sections.
 pub(crate) fn share_dialog_reload(state: &Rc<ShareDialog>) {
-    let rx = spawn_request(
-        state.ui.dirs.control_socket(),
-        Request::ListShare {
-            path: state.rel.clone(),
-        },
-    );
+    let rx = spawn_request(state.ui.dirs.control_socket(), state.target.list());
     let state = state.clone();
     glib::spawn_future_local(async move {
         match rx.recv().await {
@@ -232,12 +332,11 @@ pub(crate) fn repaint_share_people(state: &Rc<ShareDialog>, entries: &[ShareEntr
             drop.connect_selected_notify(move |d| {
                 share_dialog_op(
                     &state_role,
-                    Request::UpdateShareRole {
-                        path: state_role.rel.clone(),
-                        id: id.clone(),
+                    state_role.target.update_role(
+                        id.clone(),
                         kind,
-                        role: role_index_to_wire(d.selected()).to_string(),
-                    },
+                        role_index_to_wire(d.selected()).to_string(),
+                    ),
                     "Role updated",
                     "Couldn't update the role",
                     None,
@@ -265,11 +364,7 @@ pub(crate) fn repaint_share_people(state: &Rc<ShareDialog>, entries: &[ShareEntr
         remove.connect_clicked(move |_| {
             share_dialog_op(
                 &state_rm,
-                Request::RemoveShareEntry {
-                    path: state_rm.rel.clone(),
-                    id: id.clone(),
-                    kind,
-                },
+                state_rm.target.remove_entry(id.clone(), kind),
                 "Access removed",
                 "Couldn't remove access",
                 None,
@@ -332,10 +427,7 @@ pub(crate) fn repaint_share_link(state: &Rc<ShareDialog>, link: Option<&PublicLi
             remove.connect_clicked(move |_| {
                 share_dialog_op(
                     &state_rm,
-                    Request::RemovePublicLink {
-                        path: state_rm.rel.clone(),
-                        id: id.clone(),
-                    },
+                    state_rm.target.remove_link(id.clone()),
                     "Public link removed",
                     "Couldn't remove the link",
                     None,
@@ -407,12 +499,7 @@ pub(crate) fn share_dialog_create_link(
 ) {
     let rx = spawn_request(
         state.ui.dirs.control_socket(),
-        Request::CreatePublicLink {
-            path: state.rel.clone(),
-            role,
-            password,
-            expires: None,
-        },
+        state.target.create_link(role, password),
     );
     let state = state.clone();
     glib::spawn_future_local(async move {

docs/ARCHITECTURE.md

@@ -76,6 +76,31 @@ sequenceDiagram
     FUSE-->>User: returns child inode metadata (attributes, TTL)
 ```
 
+### Access Classification and Enforcement
+
+Every `Entry` carries an `Access` (`Owner | Editor | Viewer | Unknown`), inherited from its parent at intern time rather than resolved per node — a child is always interned from its parent's listing, so one edge lookup answers it. A known share root takes its access from the persisted `share_access` table instead, which is also what makes the classification correct offline.
+
+Two rules decide the cases inheritance cannot:
+
+* **Not under a share, no role → `Owner` (fail open).** My Files and device folders are owned content; regressing this denies ordinary writes.
+* **Under a share with no usable role → `Viewer` (fail closed).** An unrecognised permission mask is never degraded into a guess.
+
+A node whose parent is not resident is the awkward case: a device folder's parent is the device root, which is never persisted as a node, so the whole subtree hydrates parentless. It resolves the way the persisted authority (`Db::effective_node_access`) does — a recorded share row above it wins, otherwise fail open on the mount's own volume and closed on a foreign one (`docs/BUGS.md` B79).
+
+Enforcement is three layers, and only the third closes B34:
+
+1. **Mode bits.** `attr()` returns `0o555`/`0o444` for a non-writable entry, and both mount paths set `MountOption::DefaultPermissions`, so the *kernel* refuses `open(O_WRONLY)`, `access(W_OK)` and namespace operations for any non-root process.
+2. **Handler gates.** `EACCES` in `create`/`mkdir`/`unlink`/`rmdir`/`rename` (parent-writable; both parents for a rename) and in `open`-for-write/`write`/`setattr`/`fallocate`. Covers root and stale attribute TTLs.
+3. **Queue guards.** `Core::require_uid_writable` admits a mutation only when the persisted authority *and* every live inode space agree the uid is writable. Nothing reaches `pending_op` otherwise, so the perpetual failing drain that B34 describes cannot occur even if a handler check is missed. The intersection is across mounts because a uid may be resident in more than one inode space.
+
+`EACCES`, not `EROFS`, for a read-only subtree inside a read-write mount: `EROFS` means "read-only filesystem" and misleads the heuristics in `cp`, `rsync` and `git`.
+
+### Local Locations
+
+`mount` is a presentation table: one row per local place this client occupies — the primary My Files session, and each device folder in mirror or on-demand mode. `sync_folder` remains the sync engine's own table (`sync_entry` is FK'd to it) and `MountKind::Device { sync_folder_id }` is the join. `Request::ListLocations` serves the table to `pdfs locations` and the GUI's Locations page.
+
+A mirror folder is a plain local directory with no FUSE session, so a row can legitimately describe a location that is not mounted — which is why the page is called *Locations* rather than *Mounts*. The primary mountpoint stays in `AppConfig`, with its `mount` row written at daemon start as a projection of it, so there are not two sources of truth for that path.
+
 ---
 
 ## 3. Read Path & Block Caching Pipeline

docs/BUGS.md

@@ -66,7 +66,10 @@ device-folder tree to `Viewer` in memory.
 **Tests:** `state::tests::own_volume_nodes_without_a_resident_parent_stay_owned`,
 `foreign_volume_nodes_without_a_resident_parent_fail_closed`,
 `persisted_authority_outranks_the_own_volume_fail_open`. The first fails on the
-pre-fix branch with `left: Unknown, right: Owner`.
+pre-fix branch with `left: Unknown, right: Owner`. The standing live guard is the
+`regression B79` acceptance case, which finds a mounted on-demand device folder
+through `pdfs locations --json` and writes into it (skipping when this machine
+has none).
 
 **Verified live (2026-07-31):** the packaged 1.2.1 daemon denies
 `touch ~/Documents/pdfs-b79-test`, `mkdir`, and `>` redirect while

docs/DEVELOPMENT.md

@@ -58,7 +58,9 @@ Derived from: [`BUGS.md`](BUGS.md)
 * **B56–B60 — fail-closed state and IPC fixes**: Future schemas, event cursor advancement, socket limits, private-directory validation, and atomic config saves are implemented. Malformed-schema, database-full, connection-flood, wrong-owner, and concurrent/faulted-save verification remains.
 * **B61 — credential rotation persistence**: Surface and retry keyring persistence failures so a rotated single-use refresh token cannot be lost on restart.
 * **B62–B65 — release assurance**: Clean-install package verification, complete version/protocol identity, recovery sign-off, advisory/license policy, SBOM, provenance, checksums, and signatures remain.
-* **B66–B68 — lifecycle and recovery**: Add queue flush/shutdown protection, explicit device adoption during fresh-state restore, and move profile backup below a writable remote folder.
+* **B66–B67 — lifecycle and recovery**: Add queue flush/shutdown protection and explicit device adoption during fresh-state restore.
+* **B68/B78 — profile backup**: the destination is fixed and verified live — `profile.json` now lives in `.proton-drive-linux/` under the device root, since the API refuses file creation at the root itself. What remains from B68 is making backup *health* visible (today a failure is a `WARN` in the log and nothing in the UI) and re-running the replacement-machine restore end to end.
+* **B79 — cross-mount permission classification**: fixed and verified live; the standing guard is the `regression B79` acceptance case. The second-account cases it neighbours (`regression B34`) still cannot run — see below.
 
 ---
 
@@ -76,6 +78,7 @@ Derived from: [`TESTING.md`](TESTING.md) and [`RECOVERY.md`](RECOVERY.md)
   3. Wipe the local state directory and SQLite cache.
   4. Restart the daemon.
   5. Run `pdfs sync restore` and assert the recovered filesystem matches the source byte-for-byte.
+* **Second-account sharing run (mount-architecture.md P7)**: The only outstanding verification for the mount/sharing work. One account covers `context_share_id`, the shared-with-me listing, sharing from device folders and the Locations page — all confirmed. A **second account** is required for the shared-tree rendering under a foreign volume, `accept_invitation`, `update_member_role`, the `regression B34` viewer cases (which skip cleanly today), and above all an **editor-role write into a foreign share**, the only thing that validates `membership_address_for`.
 * **Managed live mode matrix**: Before release, run `scripts/fuse-acceptance.sh --managed-live <empty-a> <empty-b>` with `PDFS_ACCEPTANCE_ONLY` unset. It validates on-demand/on-demand, on-demand/mirror, mirror/on-demand, and mirror/mirror transitions.
 * **Crash-consistency matrix**: Inject failure after scratch/sidecar sync, each staging rename, directory sync, pending-op insert/commit, and source deletion; prove that a complete discoverable copy and either the old or new queue record always survives.
 

docs/TESTING.md

@@ -83,6 +83,31 @@ guard, and it was found by exactly this mechanism: the B70 case failed, and
 narrowing it produced a smaller reproduction that has its own case now. Expect a
 red run against a real mount until it is fixed.
 
+**B79** (an on-demand device folder accepts writes) discovers its target from
+`pdfs locations --json` and skips when this machine has no mounted on-demand
+folder. It is the cheap standing guard against a *cross-mount* permission
+regression: the primary mount holds device-folder nodes too, and the queue guard
+intersects what every live inode space says about a uid, so a fail-closed
+classification in one mount denies writes in another.
+
+**B34** (a viewer-role share is read-only) and **B34b** (an editor-role share
+still writes) locate their subject through `pdfs shared-with-me --json`, which
+now carries `role` and a mount-relative `path`. Both skip when the account has no
+accepted share at that role — B34 needs a **second account** to have shared a
+folder read-only, which is the one part of the sharing suite that cannot be
+self-served. B34b degrades gracefully in the other direction: a shared *file*
+gets its mode bits and `W_OK` checked but is never written to, because it is
+someone else's document.
+
+B34's fourth assertion is the load-bearing one: `pending_uploads` and
+`pending_changes` must be **unchanged** across the refused writes. Mode bits
+alone would pass a fix that still admitted the write into `pending_op`, which is
+the actual harm — a background drain failing 403 forever.
+
+**Synthetic `Shared with me/` directory contract** asserts the virtual directory
+enumerates, reports `0555`, and refuses `mkdir`/`rmdir`/`rename`. It skips when
+the directory is absent (an account with no accepted shares).
+
 A regression case asserts against the *remote* outcome, so it must wait for the
 queue to drain before reading. Reading straight back through the mount proves
 nothing: the local attribute and content caches will happily return the bytes
@@ -149,6 +174,10 @@ During development, `PDFS_ACCEPTANCE_ONLY` runs tests whose descriptive name
 contains the supplied text (for example `PDFS_ACCEPTANCE_ONLY=namespace`). A
 release acceptance run must leave it unset so the complete contract executes.
 
+A filter naming a live-only case (every `regression B<n>` is one) selects nothing
+in the account-free reference run, which is not an error — that target simply has
+nothing to do. Only a filter matching *no case at all* fails, as the typo it is.
+
 Passing more paths runs the same filesystem suite independently against each.
 The first path must be the FUSE mount under test; later paths may be another
 FUSE mount or a normal local mirror filesystem:

scripts/fuse-acceptance.py

@@ -1075,6 +1075,208 @@ def test_regression_b74_rename_after_close(ctx: Context) -> None:
     ctx.record("digest", hashlib.sha256(read(final)).hexdigest())
 
 
+SHARED_DIR_NAME = "Shared with me"
+
+
+def _locations(daemon: Daemon) -> list[dict]:
+    """Every local Proton Drive location the daemon reports."""
+    return json.loads(daemon.command("locations", json_output=True)).get("items", [])
+
+
+def _shared_with_me(daemon: Daemon) -> list[dict]:
+    return json.loads(daemon.command("shared-with-me", json_output=True)).get("entries", [])
+
+
+def _shared_root(daemon: Daemon, mount: Path, role: str) -> Path:
+    """The local path of an accepted share held at `role`.
+
+    Skips rather than fails when the account has no such share: the role cases
+    need a *second* account to have shared something at that role, which most
+    runs will not have (mount-architecture.md §7).
+    """
+    entries = [e for e in _shared_with_me(daemon) if e.get("role") == role]
+    if not entries:
+        raise Skip(f"no accepted {role}-role share on this account")
+    for entry in entries:
+        # `path` is mount-relative and filled in only once the synthetic
+        # directory has interned the node, so list it first.
+        with contextlib.suppress(OSError):
+            os.listdir(mount / SHARED_DIR_NAME)
+        relative = entry.get("path") or ""
+        if relative:
+            candidate = mount / relative
+            if candidate.exists():
+                return candidate
+    raise Skip(f"{role}-role share is not resident under {SHARED_DIR_NAME}/")
+
+
+def test_regression_b34_viewer_share_is_read_only(ctx: Context) -> None:
+    """A viewer-role share must be read-only *and* queue nothing (B34).
+
+    The harm B34 names is not the mode bits: it is that a local write into a
+    read-only share was accepted, entered `pending_op`, and then failed 403 in
+    the drain forever. So step 4 — the queue depth being unchanged across the
+    attempts — is the assertion that distinguishes the fix from cosmetics.
+    """
+    daemon = ctx.require_daemon()
+    mount = daemon.enclosing_mount(ctx.root)
+    root = _shared_root(daemon, mount, "viewer")
+
+    before = daemon.status().get("mount") or {}
+    mode = stat.S_IMODE(os.stat(root).st_mode)
+    check(mode == 0o555, f"viewer share is {mode:o}, expected 555")
+    check(not os.access(root, os.W_OK), "viewer share reports itself writable")
+
+    target = root / "b34-should-not-exist"
+    expect_errno({errno.EACCES}, lambda: os.mkdir(target), "mkdir in a viewer share")
+    expect_errno(
+        {errno.EACCES},
+        lambda: os.open(target, os.O_CREAT | os.O_WRONLY, 0o600),
+        "create in a viewer share",
+    )
+    for child in sorted(root.iterdir())[:1]:
+        child_mode = stat.S_IMODE(os.stat(child).st_mode)
+        expected = 0o555 if child.is_dir() else 0o444
+        check(child_mode == expected, f"{child.name} is {child_mode:o}, expected {expected:o}")
+        expect_errno(
+            {errno.EACCES},
+            lambda: os.open(child, os.O_WRONLY),
+            "open-for-write in a viewer share",
+        )
+        expect_errno(
+            {errno.EACCES},
+            lambda: os.rename(child, child.with_name("b34-renamed")),
+            "rename in a viewer share",
+        )
+        expect_errno(
+            {errno.EACCES},
+            lambda: (os.rmdir(child) if child.is_dir() else os.unlink(child)),
+            "remove from a viewer share",
+        )
+
+    after = daemon.status().get("mount") or {}
+    for key in ("pending_uploads", "pending_changes"):
+        check(
+            before.get(key, 0) == after.get(key, 0),
+            f"a refused write changed {key}: {before.get(key)} -> {after.get(key)}",
+        )
+    ctx.record("viewer.mode", f"{mode:o}")
+    ctx.record("viewer.queue_unchanged", True)
+
+
+def test_regression_b34b_editor_share_still_writes(ctx: Context) -> None:
+    """The fail-open half of B34: an editor share stays writable.
+
+    A permission model that denies everything would pass the viewer case and
+    break the feature, so this is the guard that the enforcement is scoped.
+    """
+    daemon = ctx.require_daemon()
+    mount = daemon.enclosing_mount(ctx.root)
+    root = _shared_root(daemon, mount, "editor")
+
+    is_dir = root.is_dir()
+    mode = stat.S_IMODE(os.stat(root).st_mode)
+    expected = 0o755 if is_dir else 0o644
+    check(mode == expected, f"editor share is {mode:o}, expected {expected:o}")
+    check(os.access(root, os.W_OK), "editor share reports itself unwritable")
+    ctx.record("editor.mode", f"{mode:o}")
+
+    # A shared *file* is someone else's document: proving the mode bits and the
+    # kernel's own W_OK answer is as far as this case goes. Only a shared folder
+    # gets a real write, and only into a file this suite created.
+    if not is_dir:
+        ctx.note("editor.write", "skipped: the editor share is a file")
+        return
+
+    payload = b"b34b-editor-write\n" * 64
+    target = root / "b34b-editor-write.bin"
+    write_durable(target, payload)
+    daemon.wait_for_queue()
+    try:
+        check_bytes(read(target), payload, "editor-share write did not read back")
+    finally:
+        with contextlib.suppress(OSError):
+            os.unlink(target)
+        daemon.wait_for_queue()
+
+
+def test_shared_directory_contract(ctx: Context) -> None:
+    """The synthetic `Shared with me/` directory behaves like a real directory.
+
+    It is a real `Node` on a reserved volume rather than a FUSE special case, so
+    it must enumerate, stat and refuse mutation like any other read-only folder —
+    and must not be creatable or removable by the user.
+    """
+    daemon = ctx.require_daemon()
+    mount = daemon.enclosing_mount(ctx.root)
+    shared = mount / SHARED_DIR_NAME
+    if not shared.is_dir():
+        raise Skip(f"{SHARED_DIR_NAME}/ is not present in this mount")
+
+    mode = stat.S_IMODE(os.stat(shared).st_mode)
+    check(mode == 0o555, f"{SHARED_DIR_NAME}/ is {mode:o}, expected 555")
+    # Enumerating must not raise: it is the operation the whole feature exists for.
+    names = sorted(os.listdir(shared))
+    expect_errno(
+        {errno.EACCES},
+        lambda: os.mkdir(shared / "b34-synthetic-child"),
+        f"mkdir inside {SHARED_DIR_NAME}/",
+    )
+    expect_errno(
+        {errno.EACCES, errno.ENOTEMPTY, errno.EBUSY},
+        lambda: os.rmdir(shared),
+        f"rmdir {SHARED_DIR_NAME}/",
+    )
+    expect_errno(
+        {errno.EACCES, errno.EEXIST},
+        lambda: os.rename(shared, mount / "b34-renamed-shared"),
+        f"rename {SHARED_DIR_NAME}/",
+    )
+    ctx.record("shared.mode", f"{mode:o}")
+    ctx.note("shared.entries", len(names))
+
+
+def test_regression_b79_ondemand_location_accepts_writes(ctx: Context) -> None:
+    """An on-demand device folder must accept writes (B79).
+
+    Every mount holds its own inode space, and the queue guard intersects the
+    access each one reports. The primary mount hydrates the device folder's
+    nodes parentless (their device root is never a persisted node), so a
+    fail-closed classification there denied every write in the *secondary*
+    mount while its own state said Owner. The symptom is EACCES on a plain
+    `touch` in `~/Documents` while `~/ProtonDrive` accepts one.
+    """
+    daemon = ctx.require_daemon()
+    locations = [
+        location
+        for location in _locations(daemon)
+        if location.get("kind", {}).get("kind") == "device"
+        and location.get("mode") == "ondemand"
+        and location.get("mounted")
+        and location.get("access") == "rw"
+    ]
+    if not locations:
+        raise Skip("no mounted on-demand device folder on this machine")
+
+    root = Path(locations[0]["local_path"])
+    payload = b"b79-ondemand-write\n" * 128
+    directory = root / "pdfs-b79-acceptance"
+    target = directory / "write.bin"
+    try:
+        os.mkdir(directory)
+        write_durable(target, payload)
+        daemon.wait_for_queue()
+        check_bytes(read(target), payload, "on-demand write did not read back")
+    finally:
+        with contextlib.suppress(OSError):
+            os.unlink(target)
+        with contextlib.suppress(OSError):
+            os.rmdir(directory)
+        with contextlib.suppress(Exception):
+            daemon.wait_for_queue()
+    ctx.record("b79.location", str(root))
+
+
 def _conflict_copies(root: Path) -> list[str]:
     return sorted(name for name in os.listdir(root) if "(sync-conflict" in name)
 
@@ -1132,6 +1334,10 @@ TESTS = [
     Case("regression B69: identical rewrite makes no conflict", test_regression_b69_identical_rewrite, (LIVE,)),
     Case("regression B70: transient download name is not sealed", test_regression_b70_transient_download_name, (LIVE,)),
     Case("regression B74: rename after close keeps its content", test_regression_b74_rename_after_close, (LIVE,)),
+    Case("regression B34: a viewer share is read-only and queues nothing", test_regression_b34_viewer_share_is_read_only, (LIVE,)),
+    Case("regression B34b: an editor share still writes", test_regression_b34b_editor_share_still_writes, (LIVE,)),
+    Case("synthetic Shared-with-me directory contract", test_shared_directory_contract, (LIVE,)),
+    Case("regression B79: an on-demand device folder accepts writes", test_regression_b79_ondemand_location_accepts_writes, (LIVE,)),
     Case("durability across a daemon restart", test_durability_across_restart, (LIVE,)),
 ]
 
@@ -1181,10 +1387,18 @@ REPORT: list[Run] = []
 def select_cases(kind: str) -> list[Case]:
     selected = os.environ.get("PDFS_ACCEPTANCE_ONLY")
     cases = [case for case in TESTS if kind in case.kinds]
-    if selected:
-        cases = [case for case in cases if selected.lower() in case.name.lower()]
-        check(bool(cases), f"PDFS_ACCEPTANCE_ONLY={selected!r} matched no tests for {kind}")
+    if not selected:
         return cases
+    needle = selected.lower()
+    # A filter that names a live-only case (every regression case is one) matches
+    # nothing in the reference run, which is not an error — the reference target
+    # simply has nothing to do. Only a filter that matches *no case at all* is a
+    # typo worth failing on.
+    check(
+        any(needle in case.name.lower() for case in TESTS),
+        f"PDFS_ACCEPTANCE_ONLY={selected!r} matched no tests",
+    )
+    return [case for case in cases if needle in case.name.lower()]
 
 
 def reap_stale_roots(parent: Path, max_age: int) -> None: