refactor(#2352): quota show via daemon wire command

hive-c0re/src/bin/hivectl.rs

@@ -20,7 +20,6 @@ use std::path::{Path, PathBuf};
 
 use anyhow::{Context as _, Result, bail};
 use clap::{Args, Parser, Subcommand};
-use hive_c0re::coordinator::Coordinator;
 
 /// Rebuild-queue DAG progress rendering (`wait_for_dags` + the spinner /
 /// plain renderers), split out to keep this file manageable. `#[path]` keeps
@@ -760,7 +759,7 @@ async fn main() -> Result<()> {
         } => choom(&name, resume_session.as_deref()),
         Cmd::Quota { cmd } => match cmd {
             QuotaCmd::Enable => quota_enable(&socket).await,
-            QuotaCmd::Show { name } => quota_show(name.as_deref()).await,
+            QuotaCmd::Show { name } => quota_show(&socket, name.as_deref()).await,
             QuotaCmd::Limit { name, size } => quota_limit(&socket, &name, &size).await,
         },
         Cmd::MarkdownDocs => {
@@ -1046,37 +1045,41 @@ async fn quota_enable(socket: &Path) -> Result<()> {
 }
 
 /// `quota show [name]` — report per-agent disk usage from btrfs qgroups.
-async fn quota_show(name: Option<&str>) -> Result<()> {
-    let agents: Vec<String> = match name {
-        Some(n) => vec![n.to_owned()],
-        None => Coordinator::kept_state_names(),
-    };
-    if agents.is_empty() {
+/// The daemon resolves the agent set + reads each subvolume's usage (it
+/// holds the privileged helper); the client just formats the returned rows.
+async fn quota_show(socket: &Path, name: Option<&str>) -> Result<()> {
+    let resp = hive_c0re::client::request(
+        socket,
+        hive_host_sock::HostRequest::QuotaShow {
+            name: name.map(str::to_owned),
+        },
+    )
+    .await
+    .with_context(|| format!("connect to daemon socket {}", socket.display()))?;
+    if !resp.ok {
+        // Carries the "btrfs quota not enabled — run `hivectl quota enable`
+        // first" hint when qgroups are off.
+        bail!("{}", resp.error.as_deref().unwrap_or("quota show failed"));
+    }
+    let rows = resp.quota.unwrap_or_default();
+    if rows.is_empty() {
         println!("no agents with a state dir found");
         return Ok(());
     }
-    for agent in &agents {
-        match hive_c0re::priv_client::read_subvolume_usage(agent).await {
-            Ok((rfer, excl)) => {
-                println!(
-                    "{agent:<12} referenced {:>10}   exclusive {:>10}",
-                    human_bytes(rfer),
-                    human_bytes(excl)
-                );
-            }
-            Err(e) => {
-                let msg = format!("{e:#}");
-                // btrfs-progs prints "ERROR: ... quota not enabled" to stderr
-                // when qgroups are off; match the stable fragment case-
-                // insensitively rather than an exact line (the surrounding
-                // wording varies across btrfs-progs versions).
-                if msg.to_ascii_lowercase().contains("quota not enabled") {
-                    bail!("btrfs quota not enabled — run `hivectl quota enable` first");
-                }
-                // A plain-dir agent (no subvolume) has no qgroup; report it
-                // inline and keep going rather than aborting the whole sweep.
-                println!("{agent:<12} (no qgroup data — plain dir or: {msg})");
-            }
+    for row in &rows {
+        match (row.referenced, row.exclusive) {
+            (Some(rfer), Some(excl)) => println!(
+                "{:<12} referenced {:>10}   exclusive {:>10}",
+                row.agent,
+                human_bytes(rfer),
+                human_bytes(excl)
+            ),
+            // Plain-dir agent (no qgroup) — the daemon set an explanatory note.
+            _ => println!(
+                "{:<12} ({})",
+                row.agent,
+                row.note.as_deref().unwrap_or("no qgroup data")
+            ),
         }
     }
     Ok(())

hive-c0re/src/server.rs

@@ -201,6 +201,7 @@ async fn dispatch(req: &HostRequest, coord: Arc<Coordinator>) -> HostResponse {
             }
             HostRequest::QuotaEnable => handle_quota_enable().await?,
             HostRequest::QuotaLimit { name, limit } => handle_quota_limit(name, *limit).await?,
+            HostRequest::QuotaShow { name } => handle_quota_show(name.as_deref()).await?,
         })
     }
     .await;
@@ -429,6 +430,45 @@ async fn handle_quota_limit(name: &str, limit: Option<u64>) -> Result<HostRespon
     Ok(HostResponse::success())
 }
 
+async fn handle_quota_show(name: Option<&str>) -> Result<HostResponse> {
+    let agents: Vec<String> = match name {
+        Some(n) => vec![n.to_owned()],
+        None => Coordinator::kept_state_names(),
+    };
+    let mut rows = Vec::with_capacity(agents.len());
+    for agent in &agents {
+        match crate::priv_client::read_subvolume_usage(agent).await {
+            Ok((referenced, exclusive)) => rows.push(hive_host_sock::QuotaRow {
+                agent: agent.clone(),
+                referenced: Some(referenced),
+                exclusive: Some(exclusive),
+                note: None,
+            }),
+            Err(e) => {
+                let msg = format!("{e:#}");
+                // btrfs-progs prints "ERROR: ... quota not enabled" to stderr
+                // when qgroups are off; short-circuit the whole sweep with the
+                // enable hint (case-insensitive fragment match — the wording
+                // varies across btrfs-progs versions).
+                if msg.to_ascii_lowercase().contains("quota not enabled") {
+                    return Ok(HostResponse::error(
+                        "btrfs quota not enabled — run `hivectl quota enable` first",
+                    ));
+                }
+                // A plain-dir agent (no subvolume) has no qgroup; note it
+                // inline and keep going rather than aborting the whole sweep.
+                rows.push(hive_host_sock::QuotaRow {
+                    agent: agent.clone(),
+                    referenced: None,
+                    exclusive: None,
+                    note: Some(format!("no qgroup data — plain dir or: {msg}")),
+                });
+            }
+        }
+    }
+    Ok(HostResponse::quota(rows))
+}
+
 async fn handle_matrix_sync_admin() -> Result<HostResponse> {
     require_matrix_present().await?;
     let register_token =

hive-host-sock/src/lib.rs

@@ -178,6 +178,35 @@ pub enum HostRequest {
         #[serde(default)]
         limit: Option<u64>,
     },
+    /// Report per-agent btrfs qgroup usage (`hivectl quota show [name]`).
+    /// The daemon resolves the agent set (all kept state dirs when `name`
+    /// is absent) and reads each subvolume's referenced/exclusive usage via
+    /// the privileged helper. Result rows land in [`HostResponse::quota`];
+    /// a "btrfs quota not enabled" error short-circuits the whole sweep as a
+    /// plain [`HostResponse::error`] so the client can print the enable hint.
+    QuotaShow {
+        #[serde(default)]
+        name: Option<String>,
+    },
+}
+
+/// One agent's btrfs qgroup usage row — the [`HostRequest::QuotaShow`]
+/// result unit. `referenced` / `exclusive` are byte counts when the agent
+/// has a live qgroup; both are `None` (with an explanatory `note`) for a
+/// plain-dir agent that has no subvolume to account. The client formats the
+/// byte counts into human-readable columns.
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct QuotaRow {
+    pub agent: String,
+    #[serde(default, skip_serializing_if = "Option::is_none")]
+    pub referenced: Option<u64>,
+    #[serde(default, skip_serializing_if = "Option::is_none")]
+    pub exclusive: Option<u64>,
+    /// Set instead of the byte counts when the agent has no qgroup data
+    /// (plain dir, or a non-"quota not enabled" read error), so the client
+    /// can print an inline explanation and keep going.
+    #[serde(default, skip_serializing_if = "Option::is_none")]
+    pub note: Option<String>,
 }
 
 /// Selects which container classes a hive-wide [`HostRequest::Stop`] /
@@ -280,6 +309,10 @@ pub struct HostResponse {
     /// Empty for requests that produce no such output.
     #[serde(default, skip_serializing_if = "Vec::is_empty")]
     pub messages: Vec<String>,
+    /// `QuotaShow` result — one row per agent with its btrfs qgroup usage.
+    /// `None` for every other request kind.
+    #[serde(default, skip_serializing_if = "Option::is_none")]
+    pub quota: Option<Vec<QuotaRow>>,
 }
 
 impl HostResponse {
@@ -369,4 +402,14 @@ impl HostResponse {
             ..Self::default()
         }
     }
+
+    /// `QuotaShow` result — one usage row per agent.
+    #[must_use]
+    pub fn quota(rows: Vec<QuotaRow>) -> Self {
+        Self {
+            ok: true,
+            quota: Some(rows),
+            ..Self::default()
+        }
+    }
 }