diff --git a/src/cli/args.rs b/src/cli/args.rs
index 12a8649..680dabe 100644
--- a/src/cli/args.rs
+++ b/src/cli/args.rs
@@ -85,24 +85,24 @@ pub struct Cli {
     /// Include removable devices (e.g., USB sticks) during discovery (default: false)
     #[arg(long = "allow-removable", default_value_t = false)]
     pub allow_removable: bool,
- 
+
     /// Attempt to mount existing filesystems based on on-disk headers; no partitioning or mkfs.
     /// Non-destructive mounting flow; uses UUID= sources and policy from config.
     #[arg(long = "mount-existing", default_value_t = false)]
     pub mount_existing: bool,
- 
+
     /// Report current initialized filesystems and mounts without performing changes.
     #[arg(long = "report-current", default_value_t = false)]
     pub report_current: bool,
- 
+
     /// Print detection and planning summary as JSON to stdout (non-default)
     #[arg(long = "show", default_value_t = false)]
     pub show: bool,
- 
+
     /// Write detection/planning JSON report to the given path
     #[arg(long = "report")]
     pub report: Option<String>,
- 
+
     /// Execute destructive actions (apply mode). When false, runs preview-only.
     #[arg(long = "apply", default_value_t = false)]
     pub apply: bool,
@@ -111,4 +111,4 @@ pub struct Cli {
 /// Parse CLI arguments (non-interactive; suitable for initramfs).
 pub fn from_args() -> Cli {
     Cli::parse()
-}
\ No newline at end of file
+}
diff --git a/src/cli/mod.rs b/src/cli/mod.rs
index 70013f6..0d5e60b 100644
--- a/src/cli/mod.rs
+++ b/src/cli/mod.rs
@@ -10,4 +10,4 @@
 
 pub mod args;
 
-pub use args::*;
\ No newline at end of file
+pub use args::*;
diff --git a/src/config/loader.rs b/src/config/loader.rs
index 3168da2..005e8e5 100644
--- a/src/config/loader.rs
+++ b/src/config/loader.rs
@@ -42,8 +42,8 @@
 
 use std::fs;
 
-use crate::{cli::Cli, Error, Result};
 use crate::types::*;
+use crate::{Error, Result, cli::Cli};
 use serde_json::{Map, Value, json};
 use tracing::warn;
 
@@ -77,17 +77,17 @@ pub fn load_and_merge(cli: &Cli) -> Result<Config> {
     let cli_overlay = cli_overlay_value(cli);
     merge_value(&mut merged, cli_overlay);
 
-   // 5) Kernel cmdline topology override only when CLI did not provide topology
-   if cli.topology.is_none() {
-       if let Some(topo) = kernel_cmdline_topology() {
-           merge_value(&mut merged, json!({"topology": topo.to_string()}));
-       }
-   }
+    // 5) Kernel cmdline topology override only when CLI did not provide topology
+    if cli.topology.is_none() {
+        if let Some(topo) = kernel_cmdline_topology() {
+            merge_value(&mut merged, json!({"topology": topo.to_string()}));
+        }
+    }
 
-   // Finalize
-   let cfg: Config = serde_json::from_value(merged).map_err(|e| Error::Other(e.into()))?;
-   validate(&cfg)?;
-   Ok(cfg)
+    // Finalize
+    let cfg: Config = serde_json::from_value(merged).map_err(|e| Error::Other(e.into()))?;
+    validate(&cfg)?;
+    Ok(cfg)
 }
 
 /// Validate semantic correctness of the configuration.
@@ -181,7 +181,9 @@ pub fn validate(cfg: &Config) -> Result<()> {
         Topology::Bcachefs2Copy => {}
         Topology::BtrfsRaid1 => {
             // No enforced requirement here beyond presence of two disks at runtime.
-            if cfg.filesystem.btrfs.raid_profile != "raid1" && cfg.filesystem.btrfs.raid_profile != "none" {
+            if cfg.filesystem.btrfs.raid_profile != "raid1"
+                && cfg.filesystem.btrfs.raid_profile != "none"
+            {
                 return Err(Error::Validation(
                     "filesystem.btrfs.raid_profile must be 'none' or 'raid1'".into(),
                 ));
@@ -203,7 +205,6 @@ fn to_value<T: serde::Serialize>(t: T) -> Result<Value> {
     serde_json::to_value(t).map_err(|e| Error::Other(e.into()))
 }
 
-
 /// Merge b into a in-place:
 /// - Objects are merged key-by-key (recursively)
 /// - Arrays and scalars replace
@@ -254,7 +255,7 @@ fn cli_overlay_value(cli: &Cli) -> Value {
     if let Some(t) = cli.topology.as_ref() {
         root.insert("topology".into(), Value::String(t.to_string()));
     }
- 
+
     Value::Object(root)
 }
 
@@ -270,7 +271,9 @@ pub fn kernel_cmdline_topology() -> Option<Topology> {
             val_opt = Some(v);
         }
         if let Some(mut val) = val_opt {
-            if (val.starts_with('"') && val.ends_with('"')) || (val.starts_with('\'') && val.ends_with('\'')) {
+            if (val.starts_with('"') && val.ends_with('"'))
+                || (val.starts_with('\'') && val.ends_with('\''))
+            {
                 val = &val[1..val.len() - 1];
             }
             let val_norm = val.trim();
@@ -365,4 +368,4 @@ fn default_config() -> Config {
             path: "/run/zosstorage/state.json".into(),
         },
     }
-}
\ No newline at end of file
+}
diff --git a/src/config/mod.rs b/src/config/mod.rs
index 90617f9..13338e3 100644
--- a/src/config/mod.rs
+++ b/src/config/mod.rs
@@ -11,5 +11,5 @@
 
 pub mod loader;
 
-pub use loader::{load_and_merge, validate};
 pub use crate::types::*;
+pub use loader::{load_and_merge, validate};
diff --git a/src/device/discovery.rs b/src/device/discovery.rs
index ed482f7..9466a2e 100644
--- a/src/device/discovery.rs
+++ b/src/device/discovery.rs
@@ -186,7 +186,10 @@ pub fn discover(filter: &DeviceFilter) -> Result<Vec<Disk>> {
     discover_with_provider(&provider, filter)
 }
 
-fn discover_with_provider<P: DeviceProvider>(provider: &P, filter: &DeviceFilter) -> Result<Vec<Disk>> {
+fn discover_with_provider<P: DeviceProvider>(
+    provider: &P,
+    filter: &DeviceFilter,
+) -> Result<Vec<Disk>> {
     let mut candidates = provider.list_block_devices()?;
     // Probe properties if provider needs to enrich
     for d in &mut candidates {
@@ -210,10 +213,15 @@ fn discover_with_provider<P: DeviceProvider>(provider: &P, filter: &DeviceFilter
         .collect();
 
     if filtered.is_empty() {
-        return Err(Error::Device("no eligible disks found after applying filters".to_string()));
+        return Err(Error::Device(
+            "no eligible disks found after applying filters".to_string(),
+        ));
     }
 
-    debug!("eligible disks: {:?}", filtered.iter().map(|d| &d.path).collect::<Vec<_>>());
+    debug!(
+        "eligible disks: {:?}",
+        filtered.iter().map(|d| &d.path).collect::<Vec<_>>()
+    );
     Ok(filtered)
 }
 
@@ -259,9 +267,10 @@ fn read_disk_size_bytes(name: &str) -> Result<u64> {
     let p = sys_block_path(name).join("size");
     let sectors = fs::read_to_string(&p)
         .map_err(|e| Error::Device(format!("read {} failed: {}", p.display(), e)))?;
-    let sectors: u64 = sectors.trim().parse().map_err(|e| {
-        Error::Device(format!("parse sectors for {} failed: {}", name, e))
-    })?;
+    let sectors: u64 = sectors
+        .trim()
+        .parse()
+        .map_err(|e| Error::Device(format!("parse sectors for {} failed: {}", name, e)))?;
     Ok(sectors.saturating_mul(512))
 }
 
@@ -287,11 +296,7 @@ fn read_optional_string(p: PathBuf) -> Option<String> {
             while s.ends_with('\n') || s.ends_with('\r') {
                 s.pop();
             }
-            if s.is_empty() {
-                None
-            } else {
-                Some(s)
-            }
+            if s.is_empty() { None } else { Some(s) }
         }
         Err(_) => None,
     }
@@ -324,9 +329,27 @@ mod tests {
     fn filter_by_size_and_include_exclude() {
         let provider = MockProvider {
             disks: vec![
-                Disk { path: "/dev/sda".into(), size_bytes: 500 * 1024 * 1024 * 1024, rotational: true, model: None, serial: None }, // 500 GiB
-                Disk { path: "/dev/nvme0n1".into(), size_bytes: 128 * 1024 * 1024 * 1024, rotational: false, model: None, serial: None }, // 128 GiB
-                Disk { path: "/dev/loop0".into(), size_bytes: 8 * 1024 * 1024 * 1024, rotational: false, model: None, serial: None }, // 8 GiB pseudo (but mock provider supplies it)
+                Disk {
+                    path: "/dev/sda".into(),
+                    size_bytes: 500 * 1024 * 1024 * 1024,
+                    rotational: true,
+                    model: None,
+                    serial: None,
+                }, // 500 GiB
+                Disk {
+                    path: "/dev/nvme0n1".into(),
+                    size_bytes: 128 * 1024 * 1024 * 1024,
+                    rotational: false,
+                    model: None,
+                    serial: None,
+                }, // 128 GiB
+                Disk {
+                    path: "/dev/loop0".into(),
+                    size_bytes: 8 * 1024 * 1024 * 1024,
+                    rotational: false,
+                    model: None,
+                    serial: None,
+                }, // 8 GiB pseudo (but mock provider supplies it)
             ],
         };
 
@@ -346,7 +369,13 @@ mod tests {
     fn no_match_returns_error() {
         let provider = MockProvider {
             disks: vec![
-                Disk { path: "/dev/sdb".into(), size_bytes: 50 * 1024 * 1024 * 1024, rotational: true, model: None, serial: None }, // 50 GiB
+                Disk {
+                    path: "/dev/sdb".into(),
+                    size_bytes: 50 * 1024 * 1024 * 1024,
+                    rotational: true,
+                    model: None,
+                    serial: None,
+                }, // 50 GiB
             ],
         };
 
@@ -363,4 +392,4 @@ mod tests {
             other => panic!("unexpected error: {:?}", other),
         }
     }
-}
\ No newline at end of file
+}
diff --git a/src/device/mod.rs b/src/device/mod.rs
index da575e3..e9a8baa 100644
--- a/src/device/mod.rs
+++ b/src/device/mod.rs
@@ -9,4 +9,4 @@
 
 pub mod discovery;
 
-pub use discovery::*;
\ No newline at end of file
+pub use discovery::*;
diff --git a/src/errors.rs b/src/errors.rs
index 07d50ed..fb90683 100644
--- a/src/errors.rs
+++ b/src/errors.rs
@@ -53,4 +53,4 @@ pub enum Error {
 }
 
 /// Crate-wide result alias.
-pub type Result<T> = std::result::Result<T, Error>;
\ No newline at end of file
+pub type Result<T> = std::result::Result<T, Error>;
diff --git a/src/fs/mod.rs b/src/fs/mod.rs
index 03726e1..c3c526b 100644
--- a/src/fs/mod.rs
+++ b/src/fs/mod.rs
@@ -9,4 +9,4 @@
 
 pub mod plan;
 
-pub use plan::*;
\ No newline at end of file
+pub use plan::*;
diff --git a/src/fs/plan.rs b/src/fs/plan.rs
index 80e6b16..4b67e28 100644
--- a/src/fs/plan.rs
+++ b/src/fs/plan.rs
@@ -18,21 +18,21 @@
 // ext: dry-run mode to emit mkfs commands without executing (future).
 // REGION: EXTENSION_POINTS-END
 //
- // REGION: SAFETY
- // safety: must not run mkfs on non-empty or unexpected partitions; assume prior validation enforced.
- // safety: ensure labels follow reserved semantics (ZOSBOOT for ESP, ZOSDATA for all data FS).
- // safety: mkfs.btrfs uses -f in apply path immediately after partitioning to handle leftover signatures.
- // REGION: SAFETY-END
+// REGION: SAFETY
+// safety: must not run mkfs on non-empty or unexpected partitions; assume prior validation enforced.
+// safety: ensure labels follow reserved semantics (ZOSBOOT for ESP, ZOSDATA for all data FS).
+// safety: mkfs.btrfs uses -f in apply path immediately after partitioning to handle leftover signatures.
+// REGION: SAFETY-END
 //
 // REGION: ERROR_MAPPING
 // errmap: external mkfs/blkid failures -> crate::Error::Tool with captured stderr.
 // errmap: planning mismatches -> crate::Error::Filesystem with context.
 // REGION: ERROR_MAPPING-END
 //
- // REGION: TODO
- // todo: bcachefs tuning flags mapping from config (compression/checksum/cache_mode) deferred
- // todo: add UUID consistency checks across multi-device filesystems
- // REGION: TODO-END
+// REGION: TODO
+// todo: bcachefs tuning flags mapping from config (compression/checksum/cache_mode) deferred
+// todo: add UUID consistency checks across multi-device filesystems
+// REGION: TODO-END
 //! Filesystem planning and creation for zosstorage.
 //!
 //! Maps partition results to concrete filesystems (vfat, btrfs, bcachefs)
@@ -42,14 +42,13 @@
 //! [fn make_filesystems](plan.rs:1).
 
 use crate::{
-    Result,
+    Error, Result,
+    partition::{PartRole, PartitionResult},
     types::{Config, Topology},
-    partition::{PartitionResult, PartRole},
     util::{run_cmd, run_cmd_capture, which_tool},
-    Error,
 };
-use tracing::{debug, warn};
 use std::fs;
+use tracing::{debug, warn};
 
 /// Filesystem kinds supported by zosstorage.
 #[derive(Debug, Clone, Copy)]
@@ -97,17 +96,14 @@ pub struct FsResult {
     pub label: String,
 }
 
-    /// Determine which partitions get which filesystem based on topology.
-    ///
-    /// Rules:
-    /// - ESP partitions => Vfat with label from cfg.filesystem.vfat.label (reserved "ZOSBOOT")
-    /// - Data partitions => Btrfs with label cfg.filesystem.btrfs.label ("ZOSDATA"), unless topology SsdHddBcachefs
-    /// - SsdHddBcachefs => pair one Cache partition (SSD) with one Data partition (HDD) into one Bcachefs FsSpec with devices [cache, data] and label cfg.filesystem.bcachefs.label ("ZOSDATA")
-    /// - DualIndependent/BtrfsRaid1 => map each Data partition to its own Btrfs FsSpec (raid profile concerns are handled later during mkfs)
-pub fn plan_filesystems(
-    parts: &[PartitionResult],
-    cfg: &Config,
-) -> Result<FsPlan> {
+/// Determine which partitions get which filesystem based on topology.
+///
+/// Rules:
+/// - ESP partitions => Vfat with label from cfg.filesystem.vfat.label (reserved "ZOSBOOT")
+/// - Data partitions => Btrfs with label cfg.filesystem.btrfs.label ("ZOSDATA"), unless topology SsdHddBcachefs
+/// - SsdHddBcachefs => pair one Cache partition (SSD) with one Data partition (HDD) into one Bcachefs FsSpec with devices [cache, data] and label cfg.filesystem.bcachefs.label ("ZOSDATA")
+/// - DualIndependent/BtrfsRaid1 => map each Data partition to its own Btrfs FsSpec (raid profile concerns are handled later during mkfs)
+pub fn plan_filesystems(parts: &[PartitionResult], cfg: &Config) -> Result<FsPlan> {
     let mut specs: Vec<FsSpec> = Vec::new();
 
     // Always map ESP partitions
@@ -122,10 +118,22 @@ pub fn plan_filesystems(
     match cfg.topology {
         Topology::SsdHddBcachefs => {
             // Expect exactly one cache (SSD) and at least one data (HDD). Use the first data for pairing.
-            let cache = parts.iter().find(|p| matches!(p.role, PartRole::Cache))
-                .ok_or_else(|| Error::Filesystem("expected a Cache partition for SsdHddBcachefs topology".to_string()))?;
-            let data = parts.iter().find(|p| matches!(p.role, PartRole::Data))
-                .ok_or_else(|| Error::Filesystem("expected a Data partition for SsdHddBcachefs topology".to_string()))?;
+            let cache = parts
+                .iter()
+                .find(|p| matches!(p.role, PartRole::Cache))
+                .ok_or_else(|| {
+                    Error::Filesystem(
+                        "expected a Cache partition for SsdHddBcachefs topology".to_string(),
+                    )
+                })?;
+            let data = parts
+                .iter()
+                .find(|p| matches!(p.role, PartRole::Data))
+                .ok_or_else(|| {
+                    Error::Filesystem(
+                        "expected a Data partition for SsdHddBcachefs topology".to_string(),
+                    )
+                })?;
 
             specs.push(FsSpec {
                 kind: FsKind::Bcachefs,
@@ -173,8 +181,14 @@ pub fn plan_filesystems(
         }
         Topology::BcachefsSingle => {
             // Single-device bcachefs on the sole Data partition.
-            let data = parts.iter().find(|p| matches!(p.role, PartRole::Data))
-                .ok_or_else(|| Error::Filesystem("expected a Data partition for BcachefsSingle topology".to_string()))?;
+            let data = parts
+                .iter()
+                .find(|p| matches!(p.role, PartRole::Data))
+                .ok_or_else(|| {
+                    Error::Filesystem(
+                        "expected a Data partition for BcachefsSingle topology".to_string(),
+                    )
+                })?;
             specs.push(FsSpec {
                 kind: FsKind::Bcachefs,
                 devices: vec![data.device_path.clone()],
@@ -194,7 +208,9 @@ pub fn plan_filesystems(
     }
 
     if specs.is_empty() {
-        return Err(Error::Filesystem("no filesystems to create from provided partitions".to_string()));
+        return Err(Error::Filesystem(
+            "no filesystems to create from provided partitions".to_string(),
+        ));
     }
 
     Ok(FsPlan { specs })
@@ -215,7 +231,9 @@ pub fn make_filesystems(plan: &FsPlan, cfg: &Config) -> Result<Vec<FsResult>> {
     let blkid_tool = which_tool("blkid")?;
 
     if blkid_tool.is_none() {
-        return Err(Error::Filesystem("blkid not found in PATH; cannot capture filesystem UUIDs".into()));
+        return Err(Error::Filesystem(
+            "blkid not found in PATH; cannot capture filesystem UUIDs".into(),
+        ));
     }
     let blkid = blkid_tool.unwrap();
 
@@ -248,7 +266,9 @@ pub fn make_filesystems(plan: &FsPlan, cfg: &Config) -> Result<Vec<FsResult>> {
                     return Err(Error::Filesystem("mkfs.btrfs not found in PATH".into()));
                 };
                 if spec.devices.is_empty() {
-                    return Err(Error::Filesystem("btrfs requires at least one device".into()));
+                    return Err(Error::Filesystem(
+                        "btrfs requires at least one device".into(),
+                    ));
                 }
                 // mkfs.btrfs -L LABEL [ -m raid1 -d raid1 (when multi-device/raid1) ] dev1 [dev2 ...]
                 let mut args: Vec<String> = vec![mkfs.clone(), "-L".into(), spec.label.clone()];
@@ -288,11 +308,18 @@ pub fn make_filesystems(plan: &FsPlan, cfg: &Config) -> Result<Vec<FsResult>> {
                     return Err(Error::Filesystem("bcachefs not found in PATH".into()));
                 };
                 if spec.devices.is_empty() {
-                    return Err(Error::Filesystem("bcachefs requires at least one device".into()));
+                    return Err(Error::Filesystem(
+                        "bcachefs requires at least one device".into(),
+                    ));
                 }
                 // bcachefs format --label LABEL [--replicas=2] dev1 [dev2 ...]
                 // Apply replicas policy for Bcachefs2Copy topology (data+metadata replicas = 2)
-                let mut args: Vec<String> = vec![mkfs.clone(), "format".into(), "--label".into(), spec.label.clone()];
+                let mut args: Vec<String> = vec![
+                    mkfs.clone(),
+                    "format".into(),
+                    "--label".into(),
+                    spec.label.clone(),
+                ];
                 if matches!(cfg.topology, Topology::Bcachefs2Copy) {
                     args.push("--replicas=2".into());
                 }
@@ -318,29 +345,32 @@ pub fn make_filesystems(plan: &FsPlan, cfg: &Config) -> Result<Vec<FsResult>> {
 }
 
 fn capture_uuid(blkid: &str, dev: &str) -> Result<String> {
-   // blkid -o export /dev/...
-   let out = run_cmd_capture(&[blkid, "-o", "export", dev])?;
-   let map = parse_blkid_export(&out.stdout);
-   // Prefer ID_FS_UUID if present, fall back to UUID
-   if let Some(u) = map.get("ID_FS_UUID") {
-       return Ok(u.clone());
-   }
-   if let Some(u) = map.get("UUID") {
-       return Ok(u.clone());
-   }
-   warn!("blkid did not report UUID for {}", dev);
-   Err(Error::Filesystem(format!("missing UUID in blkid output for {}", dev)))
+    // blkid -o export /dev/...
+    let out = run_cmd_capture(&[blkid, "-o", "export", dev])?;
+    let map = parse_blkid_export(&out.stdout);
+    // Prefer ID_FS_UUID if present, fall back to UUID
+    if let Some(u) = map.get("ID_FS_UUID") {
+        return Ok(u.clone());
+    }
+    if let Some(u) = map.get("UUID") {
+        return Ok(u.clone());
+    }
+    warn!("blkid did not report UUID for {}", dev);
+    Err(Error::Filesystem(format!(
+        "missing UUID in blkid output for {}",
+        dev
+    )))
 }
 
 /// Minimal parser for blkid -o export KEY=VAL lines.
 fn parse_blkid_export(s: &str) -> std::collections::HashMap<String, String> {
-   let mut map = std::collections::HashMap::new();
-   for line in s.lines() {
-       if let Some((k, v)) = line.split_once('=') {
-           map.insert(k.trim().to_string(), v.trim().to_string());
-       }
-   }
-   map
+    let mut map = std::collections::HashMap::new();
+    for line in s.lines() {
+        if let Some((k, v)) = line.split_once('=') {
+            map.insert(k.trim().to_string(), v.trim().to_string());
+        }
+    }
+    map
 }
 
 /// Probe existing filesystems on the system and return their identities (kind, uuid, label).
@@ -354,13 +384,16 @@ fn parse_blkid_export(s: &str) -> std::collections::HashMap<String, String> {
 /// - Vec<FsResult> with at most one entry per filesystem UUID.
 pub fn probe_existing_filesystems() -> Result<Vec<FsResult>> {
     let Some(blkid) = which_tool("blkid")? else {
-        return Err(Error::Filesystem("blkid not found in PATH; cannot probe existing filesystems".into()));
+        return Err(Error::Filesystem(
+            "blkid not found in PATH; cannot probe existing filesystems".into(),
+        ));
     };
 
     let content = fs::read_to_string("/proc/partitions")
         .map_err(|e| Error::Filesystem(format!("/proc/partitions read error: {}", e)))?;
 
-    let mut results_by_uuid: std::collections::HashMap<String, FsResult> = std::collections::HashMap::new();
+    let mut results_by_uuid: std::collections::HashMap<String, FsResult> =
+        std::collections::HashMap::new();
 
     for line in content.lines() {
         let line = line.trim();
@@ -399,11 +432,13 @@ pub fn probe_existing_filesystems() -> Result<Vec<FsResult>> {
         let map = parse_blkid_export(&out.stdout);
         let ty = map.get("TYPE").cloned().unwrap_or_default();
         let label = map
-            .get("ID_FS_LABEL").cloned()
+            .get("ID_FS_LABEL")
+            .cloned()
             .or_else(|| map.get("LABEL").cloned())
             .unwrap_or_default();
         let uuid = map
-            .get("ID_FS_UUID").cloned()
+            .get("ID_FS_UUID")
+            .cloned()
             .or_else(|| map.get("UUID").cloned());
 
         let (kind_opt, expected_label) = match ty.as_str() {
@@ -434,13 +469,13 @@ pub fn probe_existing_filesystems() -> Result<Vec<FsResult>> {
 
 #[cfg(test)]
 mod tests_parse {
-   use super::parse_blkid_export;
+    use super::parse_blkid_export;
 
-   #[test]
-   fn parse_export_ok() {
-       let s = "ID_FS_UUID=abcd-1234\nUUID=abcd-1234\nTYPE=btrfs\n";
-       let m = parse_blkid_export(s);
-       assert_eq!(m.get("ID_FS_UUID").unwrap(), "abcd-1234");
-       assert_eq!(m.get("TYPE").unwrap(), "btrfs");
-   }
-}
\ No newline at end of file
+    #[test]
+    fn parse_export_ok() {
+        let s = "ID_FS_UUID=abcd-1234\nUUID=abcd-1234\nTYPE=btrfs\n";
+        let m = parse_blkid_export(s);
+        assert_eq!(m.get("ID_FS_UUID").unwrap(), "abcd-1234");
+        assert_eq!(m.get("TYPE").unwrap(), "btrfs");
+    }
+}
diff --git a/src/idempotency/mod.rs b/src/idempotency/mod.rs
index 7696e9c..7dabea2 100644
--- a/src/idempotency/mod.rs
+++ b/src/idempotency/mod.rs
@@ -28,14 +28,14 @@
 //! disks are empty before making any destructive changes.
 
 use crate::{
-    device::Disk,
-    report::{StateReport, REPORT_VERSION},
-    util::{run_cmd_capture, which_tool},
     Error, Result,
+    device::Disk,
+    report::{REPORT_VERSION, StateReport},
+    util::{run_cmd_capture, which_tool},
 };
+use humantime::format_rfc3339;
 use serde_json::json;
 use std::{collections::HashMap, fs, path::Path};
-use humantime::format_rfc3339;
 use tracing::{debug, warn};
 
 /// Return existing state if system is already provisioned; otherwise None.
@@ -155,7 +155,10 @@ pub fn is_empty_disk(disk: &Disk) -> Result<bool> {
 
     // Probe with blkid -p
     let Some(blkid) = which_tool("blkid")? else {
-        warn!("blkid not found; conservatively treating {} as not empty", disk.path);
+        warn!(
+            "blkid not found; conservatively treating {} as not empty",
+            disk.path
+        );
         return Ok(false);
     };
 
@@ -237,7 +240,11 @@ fn is_partition_of(base: &str, name: &str) -> bool {
     if name == base {
         return false;
     }
-    let ends_with_digit = base.chars().last().map(|c| c.is_ascii_digit()).unwrap_or(false);
+    let ends_with_digit = base
+        .chars()
+        .last()
+        .map(|c| c.is_ascii_digit())
+        .unwrap_or(false);
     if ends_with_digit {
         // nvme0n1 -> nvme0n1p1
         if name.starts_with(base) {
@@ -281,4 +288,4 @@ mod tests {
         assert!(!is_partition_of("nvme0n1", "nvme0n1"));
         assert!(!is_partition_of("nvme0n1", "nvme0n2p1"));
     }
-}
\ No newline at end of file
+}
diff --git a/src/lib.rs b/src/lib.rs
index 654552d..e27de18 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -1,20 +1,20 @@
 //! Crate root for zosstorage: one-shot disk provisioning utility for initramfs.
 
 pub mod cli;
-pub mod logging;
 pub mod config;
 pub mod device;
-pub mod partition;
-pub mod fs;
-pub mod mount;
-pub mod report;
-pub mod orchestrator;
-pub mod idempotency;
-pub mod util;
 pub mod errors;
-pub mod types; // top-level types (moved from config/types.rs for visibility)
+pub mod fs;
+pub mod idempotency;
+pub mod logging;
+pub mod mount;
+pub mod orchestrator;
+pub mod partition;
+pub mod report;
+pub mod types;
+pub mod util; // top-level types (moved from config/types.rs for visibility)
 
 pub use errors::{Error, Result};
 
 /// Crate version string from Cargo.
-pub const VERSION: &str = env!("CARGO_PKG_VERSION");
\ No newline at end of file
+pub const VERSION: &str = env!("CARGO_PKG_VERSION");
diff --git a/src/logging/mod.rs b/src/logging/mod.rs
index 8b031bf..1b7a5d6 100644
--- a/src/logging/mod.rs
+++ b/src/logging/mod.rs
@@ -36,10 +36,10 @@ use std::fs::OpenOptions;
 use std::io::{self};
 use std::sync::OnceLock;
 use tracing::Level;
+use tracing_subscriber::filter::LevelFilter;
 use tracing_subscriber::fmt;
 use tracing_subscriber::prelude::*;
 use tracing_subscriber::registry::Registry;
-use tracing_subscriber::filter::LevelFilter;
 use tracing_subscriber::util::SubscriberInitExt;
 
 /// Logging options resolved from CLI and/or config.
@@ -116,21 +116,27 @@ pub fn init_logging(opts: &LogOptions) -> Result<()> {
                 .with(stderr_layer)
                 .with(file_layer)
                 .try_init()
-                .map_err(|e| crate::Error::Other(anyhow::anyhow!("failed to set global logger: {}", e)))?;
+                .map_err(|e| {
+                    crate::Error::Other(anyhow::anyhow!("failed to set global logger: {}", e))
+                })?;
         } else {
             // Fall back to stderr-only if file cannot be opened
             Registry::default()
                 .with(stderr_layer)
                 .try_init()
-                .map_err(|e| crate::Error::Other(anyhow::anyhow!("failed to set global logger: {}", e)))?;
+                .map_err(|e| {
+                    crate::Error::Other(anyhow::anyhow!("failed to set global logger: {}", e))
+                })?;
         }
     } else {
         Registry::default()
             .with(stderr_layer)
             .try_init()
-            .map_err(|e| crate::Error::Other(anyhow::anyhow!("failed to set global logger: {}", e)))?;
+            .map_err(|e| {
+                crate::Error::Other(anyhow::anyhow!("failed to set global logger: {}", e))
+            })?;
     }
 
     let _ = INIT_GUARD.set(());
     Ok(())
-}
\ No newline at end of file
+}
diff --git a/src/main.rs b/src/main.rs
index 82dd4c7..23bb279 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -56,6 +56,8 @@ fn real_main() -> Result<()> {
         .with_report_current(cli.report_current)
         .with_report_path(cli.report.clone())
         .with_topology_from_cli(cli.topology.is_some())
-        .with_topology_from_cmdline(config::loader::kernel_cmdline_topology().is_some() && cli.topology.is_none());
+        .with_topology_from_cmdline(
+            config::loader::kernel_cmdline_topology().is_some() && cli.topology.is_none(),
+        );
     orchestrator::run(&ctx)
 }
diff --git a/src/mount/mod.rs b/src/mount/mod.rs
index 7447a54..935ea06 100644
--- a/src/mount/mod.rs
+++ b/src/mount/mod.rs
@@ -9,4 +9,4 @@
 
 pub mod ops;
 
-pub use ops::*;
\ No newline at end of file
+pub use ops::*;
diff --git a/src/mount/ops.rs b/src/mount/ops.rs
index ff9c926..6f3c691 100644
--- a/src/mount/ops.rs
+++ b/src/mount/ops.rs
@@ -36,13 +36,13 @@
 #![allow(dead_code)]
 
 use crate::{
+    Error, Result,
     fs::{FsKind, FsResult},
     types::Config,
     util::{run_cmd, run_cmd_capture, which_tool},
-    Error, Result,
 };
 use std::collections::HashMap;
-use std::fs::{create_dir_all, File};
+use std::fs::{File, create_dir_all};
 use std::io::Write;
 use std::path::Path;
 use tracing::info;
@@ -120,21 +120,39 @@ fn source_matches_uuid(existing_source: &str, uuid: &str) -> bool {
     false
 }
 
+fn disk_of_device(dev: &str) -> Option<String> {
+    let path = Path::new(dev);
+    let name = path.file_name()?.to_str()?;
+    let mut cutoff = name.len();
+    while cutoff > 0 && name.as_bytes()[cutoff - 1].is_ascii_digit() {
+        cutoff -= 1;
+    }
+    if cutoff == name.len() {
+        return Some(dev.to_string());
+    }
+    let mut disk = name[..cutoff].to_string();
+    if disk.ends_with('p') {
+        disk.pop();
+    }
+    let parent = path.parent()?.to_str().unwrap_or("/dev");
+    Some(format!("{}/{}", parent, disk))
+}
+
 #[derive(Debug, Clone)]
 pub struct PlannedMount {
-    pub uuid: String,     // UUID string without prefix
-    pub target: String,   // absolute path
-    pub fstype: String,   // "btrfs" | "bcachefs"
-    pub options: String,  // e.g., "rw,noatime,subvolid=5"
+    pub uuid: String,    // UUID string without prefix
+    pub target: String,  // absolute path
+    pub fstype: String,  // "btrfs" | "bcachefs"
+    pub options: String, // e.g., "rw,noatime,subvolid=5"
 }
 
 #[derive(Debug, Clone)]
 pub struct PlannedSubvolMount {
-    pub uuid: String,     // UUID of primary FS
-    pub name: String,     // subvol name (system/etc/modules/vm-meta)
-    pub target: String,   // absolute final target
-    pub fstype: String,   // "btrfs" | "bcachefs"
-    pub options: String,  // e.g., "rw,noatime,subvol=system"
+    pub uuid: String,    // UUID of primary FS
+    pub name: String,    // subvol name (system/etc/modules/vm-meta)
+    pub target: String,  // absolute final target
+    pub fstype: String,  // "btrfs" | "bcachefs"
+    pub options: String, // e.g., "rw,noatime,subvol=system"
 }
 
 /// Mount plan per policy.
@@ -202,11 +220,27 @@ pub fn plan_mounts(fs_results: &[FsResult], _cfg: &Config) -> Result<MountPlan>
         });
     }
 
-    // Determine primary UUID
-    let primary_uuid = Some(data[0].uuid.clone());
+    let primary = data[0];
+    let primary_uuid = Some(primary.uuid.clone());
+    let primary_disk = primary.devices.first().and_then(|dev| disk_of_device(dev));
 
-    // Optional ESP (VFAT) mount at /boot
-    if let Some(esp) = fs_results.iter().find(|r| matches!(r.kind, FsKind::Vfat)) {
+    let mut chosen_esp: Option<&FsResult> = None;
+    let mut fallback_esp: Option<&FsResult> = None;
+    for esp in fs_results.iter().filter(|r| matches!(r.kind, FsKind::Vfat)) {
+        if fallback_esp.is_none() {
+            fallback_esp = Some(esp);
+        }
+        if let (Some(ref disk), Some(esp_disk)) = (
+            primary_disk.as_ref(),
+            esp.devices.first().and_then(|dev| disk_of_device(dev)),
+        ) {
+            if esp_disk == **disk {
+                chosen_esp = Some(esp);
+                break;
+            }
+        }
+    }
+    if let Some(esp) = chosen_esp.or(fallback_esp) {
         root_mounts.push(PlannedMount {
             uuid: esp.uuid.clone(),
             target: BOOT_TARGET.to_string(),
@@ -216,7 +250,6 @@ pub fn plan_mounts(fs_results: &[FsResult], _cfg: &Config) -> Result<MountPlan>
     }
 
     // Subvol mounts only from primary FS
-    let primary = data[0];
     let mut subvol_mounts: Vec<PlannedSubvolMount> = Vec::new();
     let fstype = fstype_str(primary.kind).to_string();
     // Option key differs per filesystem: btrfs uses subvol=, bcachefs uses X-mount.subdir=
@@ -360,14 +393,18 @@ pub fn apply_mounts(plan: &MountPlan) -> Result<Vec<MountResult>> {
                 if !exists {
                     // Create subvolume
                     let subvol_path = format!("{}/{}", root, sm.name);
-                    let args = [btrfs_tool.as_str(), "subvolume", "create", subvol_path.as_str()];
+                    let args = [
+                        btrfs_tool.as_str(),
+                        "subvolume",
+                        "create",
+                        subvol_path.as_str(),
+                    ];
                     run_cmd(&args)?;
                 }
             }
         } else if primary_kind == "bcachefs" {
-            let bcachefs_tool = which_tool("bcachefs")?.ok_or_else(|| {
-                Error::Mount("required tool 'bcachefs' not found in PATH".into())
-            })?;
+            let bcachefs_tool = which_tool("bcachefs")?
+                .ok_or_else(|| Error::Mount("required tool 'bcachefs' not found in PATH".into()))?;
             for sm in &plan.subvol_mounts {
                 if &sm.uuid != primary_uuid {
                     continue;
@@ -479,10 +516,7 @@ pub fn maybe_write_fstab(mounts: &[MountResult], cfg: &Config) -> Result<()> {
     let mut lines: Vec<String> = Vec::new();
     for m in root_entries.into_iter().chain(subvol_entries.into_iter()) {
         // m.source already "UUID=..."
-        let line = format!(
-            "{} {} {} {} 0 0",
-            m.source, m.target, m.fstype, m.options
-        );
+        let line = format!("{} {} {} {} 0 0", m.source, m.target, m.fstype, m.options);
         lines.push(line);
     }
 
@@ -511,4 +545,4 @@ pub fn maybe_write_fstab(mounts: &[MountResult], cfg: &Config) -> Result<()> {
     })?;
 
     Ok(())
-}
\ No newline at end of file
+}
diff --git a/src/orchestrator/mod.rs b/src/orchestrator/mod.rs
index e6d7209..e58670f 100644
--- a/src/orchestrator/mod.rs
+++ b/src/orchestrator/mod.rs
@@ -3,4 +3,4 @@
 //! Re-exports the concrete implementation from run.rs to avoid duplicating types/functions.
 
 pub mod run;
-pub use run::*;
\ No newline at end of file
+pub use run::*;
diff --git a/src/orchestrator/run.rs b/src/orchestrator/run.rs
index 59f0a9f..2505113 100644
--- a/src/orchestrator/run.rs
+++ b/src/orchestrator/run.rs
@@ -43,14 +43,13 @@
 //! - Report generation and write
 
 use crate::{
-    types::{Config, Topology},
+    Error, Result,
+    device::{DeviceFilter, Disk, discover},
+    fs as zfs, idempotency,
     logging::LogOptions,
-    device::{discover, DeviceFilter, Disk},
-    idempotency,
     partition,
     report::StateReport,
-    fs as zfs,
-    Error, Result,
+    types::{Config, Topology},
 };
 use humantime::format_rfc3339;
 use regex::Regex;
@@ -191,9 +190,7 @@ pub fn run(ctx: &Context) -> Result<()> {
     info!("orchestrator: starting run()");
 
     let selected_modes =
-        (ctx.mount_existing as u8) +
-        (ctx.report_current as u8) +
-        (ctx.apply as u8);
+        (ctx.mount_existing as u8) + (ctx.report_current as u8) + (ctx.apply as u8);
     if selected_modes > 1 {
         return Err(Error::Validation(
             "choose only one mode: --mount-existing | --report-current | --apply".into(),
@@ -242,7 +239,11 @@ fn auto_select_mode(ctx: &Context) -> Result<AutoSelection> {
         info!("orchestrator: provisioned state detected; attempting mount-existing flow");
         return Ok(AutoSelection {
             decision: AutoDecision::MountExisting,
-            fs_results: if fs_results.is_empty() { None } else { Some(fs_results) },
+            fs_results: if fs_results.is_empty() {
+                None
+            } else {
+                Some(fs_results)
+            },
             state: Some(state),
         });
     }
@@ -330,9 +331,8 @@ fn run_report_current(ctx: &Context) -> Result<()> {
 
     println!("{}", summary);
     if let Some(path) = &ctx.report_path_override {
-        fs::write(path, summary.to_string()).map_err(|e| {
-            Error::Report(format!("failed to write report to {}: {}", path, e))
-        })?;
+        fs::write(path, summary.to_string())
+            .map_err(|e| Error::Report(format!("failed to write report to {}: {}", path, e)))?;
         info!("orchestrator: wrote report-current to {}", path);
     }
     Ok(())
@@ -409,9 +409,8 @@ fn run_mount_existing(
             println!("{}", summary);
         }
         if let Some(path) = &ctx.report_path_override {
-            fs::write(path, summary.to_string()).map_err(|e| {
-                Error::Report(format!("failed to write report to {}: {}", path, e))
-            })?;
+            fs::write(path, summary.to_string())
+                .map_err(|e| Error::Report(format!("failed to write report to {}: {}", path, e)))?;
             info!("orchestrator: wrote mount-existing report to {}", path);
         }
     }
@@ -445,7 +444,9 @@ fn run_provisioning(
             enforce_empty_disks(&disks)?;
             info!("orchestrator: all target disks verified empty");
         } else {
-            warn!("orchestrator: preview mode detected (--show/--report); skipping empty-disk enforcement");
+            warn!(
+                "orchestrator: preview mode detected (--show/--report); skipping empty-disk enforcement"
+            );
         }
     } else if matches!(mode, ProvisioningMode::Apply) {
         warn!("orchestrator: require_empty_disks=false; proceeding without emptiness enforcement");
@@ -506,7 +507,9 @@ fn run_provisioning(
         return Ok(());
     }
 
-    info!("orchestrator: pre-flight complete (idempotency checked, devices discovered, plan computed)");
+    info!(
+        "orchestrator: pre-flight complete (idempotency checked, devices discovered, plan computed)"
+    );
 
     if preview_outputs {
         let summary = build_summary_json(&disks, &plan, &effective_cfg)?;
@@ -514,9 +517,8 @@ fn run_provisioning(
             println!("{}", summary);
         }
         if let Some(path) = &ctx.report_path_override {
-            fs::write(path, summary.to_string()).map_err(|e| {
-                Error::Report(format!("failed to write report to {}: {}", path, e))
-            })?;
+            fs::write(path, summary.to_string())
+                .map_err(|e| Error::Report(format!("failed to write report to {}: {}", path, e)))?;
             info!("orchestrator: wrote summary report to {}", path);
         }
     }
@@ -536,15 +538,13 @@ fn build_device_filter(cfg: &Config) -> Result<DeviceFilter> {
     let mut exclude = Vec::new();
 
     for pat in &cfg.device_selection.include_patterns {
-        let re = Regex::new(pat).map_err(|e| {
-            Error::Validation(format!("invalid include regex '{}': {}", pat, e))
-        })?;
+        let re = Regex::new(pat)
+            .map_err(|e| Error::Validation(format!("invalid include regex '{}': {}", pat, e)))?;
         include.push(re);
     }
     for pat in &cfg.device_selection.exclude_patterns {
-        let re = Regex::new(pat).map_err(|e| {
-            Error::Validation(format!("invalid exclude regex '{}': {}", pat, e))
-        })?;
+        let re = Regex::new(pat)
+            .map_err(|e| Error::Validation(format!("invalid exclude regex '{}': {}", pat, e)))?;
         exclude.push(re);
     }
 
@@ -598,7 +598,11 @@ fn role_str(role: partition::PartRole) -> &'static str {
 /// - mount: scheme summary and target template (e.g., "/var/cache/{UUID}")
 ///
 /// This function is non-destructive and performs no probing beyond the provided inputs.
-fn build_summary_json(disks: &[Disk], plan: &partition::PartitionPlan, cfg: &Config) -> Result<serde_json::Value> {
+fn build_summary_json(
+    disks: &[Disk],
+    plan: &partition::PartitionPlan,
+    cfg: &Config,
+) -> Result<serde_json::Value> {
     // Disks summary
     let disks_json: Vec<serde_json::Value> = disks
         .iter()
@@ -730,4 +734,4 @@ fn build_summary_json(disks: &[Disk], plan: &partition::PartitionPlan, cfg: &Con
     });
 
     Ok(summary)
-}
\ No newline at end of file
+}
diff --git a/src/partition/mod.rs b/src/partition/mod.rs
index 6b081fd..ae2ff56 100644
--- a/src/partition/mod.rs
+++ b/src/partition/mod.rs
@@ -9,4 +9,4 @@
 
 pub mod plan;
 
-pub use plan::*;
\ No newline at end of file
+pub use plan::*;
diff --git a/src/partition/plan.rs b/src/partition/plan.rs
index b48b2c9..7338b7c 100644
--- a/src/partition/plan.rs
+++ b/src/partition/plan.rs
@@ -19,12 +19,12 @@
 // ext: device-specific alignment or reserved areas configurable via cfg in the future.
 // REGION: EXTENSION_POINTS-END
 //
- // REGION: SAFETY
- // safety: must verify require_empty_disks before any modification.
- // safety: when UEFI-booted, suppress creating BIOS boot partition to avoid unnecessary ef02 on UEFI systems.
- // safety: must ensure unique partition GUIDs; identical labels are allowed when expected (e.g., ESP ZOSBOOT).
- // safety: must call udev settle after partition table writes.
- // REGION: SAFETY-END
+// REGION: SAFETY
+// safety: must verify require_empty_disks before any modification.
+// safety: when UEFI-booted, suppress creating BIOS boot partition to avoid unnecessary ef02 on UEFI systems.
+// safety: must ensure unique partition GUIDs; identical labels are allowed when expected (e.g., ESP ZOSBOOT).
+// safety: must call udev settle after partition table writes.
+// REGION: SAFETY-END
 //
 // REGION: ERROR_MAPPING
 // errmap: external tool failure -> crate::Error::Tool { tool, status, stderr }.
@@ -44,11 +44,11 @@
 //! [fn apply_partitions](plan.rs:1).
 
 use crate::{
-    types::{Config, Topology},
-    device::Disk,
-    util::{run_cmd, run_cmd_capture, which_tool, udev_settle, is_efi_boot},
-    idempotency,
     Error, Result,
+    device::Disk,
+    idempotency,
+    types::{Config, Topology},
+    util::{is_efi_boot, run_cmd, run_cmd_capture, udev_settle, which_tool},
 };
 use tracing::{debug, warn};
 
@@ -117,20 +117,20 @@ pub struct PartitionResult {
     pub device_path: String,
 }
 
-    /// Compute GPT-only plan per topology and constraints.
-    ///
-    /// Layout defaults:
-    /// - BIOS boot: cfg.partitioning.bios_boot if enabled (size_mib)
-    /// - ESP: cfg.partitioning.esp.size_mib, GPT name cfg.partitioning.esp.gpt_name (typically "zosboot")
-    /// - Data: remainder, GPT name cfg.partitioning.data.gpt_name ("zosdata")
-    /// - Cache (only for SSD/HDD topology): remainder on SSD after boot/ESP, GPT name cfg.partitioning.cache.gpt_name ("zoscache")
-    ///
-    /// Topology mapping:
-    /// - Single: use first eligible disk; create BIOS (opt) + ESP + Data
-    /// - DualIndependent: need at least 2 disks; disk0: BIOS (opt) + ESP + Data, disk1: Data
-    /// - BtrfsRaid1: need at least 2 disks; disk0: BIOS (opt) + ESP + Data, disk1: Data
-    /// - SsdHddBcachefs: need >=1 SSD (rotational=false) and >=1 HDD (rotational=true);
-    ///     SSD: BIOS (opt) + ESP + Cache; HDD: Data
+/// Compute GPT-only plan per topology and constraints.
+///
+/// Layout defaults:
+/// - BIOS boot: cfg.partitioning.bios_boot if enabled (size_mib)
+/// - ESP: cfg.partitioning.esp.size_mib, GPT name cfg.partitioning.esp.gpt_name (typically "zosboot")
+/// - Data: remainder, GPT name cfg.partitioning.data.gpt_name ("zosdata")
+/// - Cache (only for SSD/HDD topology): remainder on SSD after boot/ESP, GPT name cfg.partitioning.cache.gpt_name ("zoscache")
+///
+/// Topology mapping:
+/// - Single: use first eligible disk; create BIOS (opt) + ESP + Data
+/// - DualIndependent: need at least 2 disks; disk0: BIOS (opt) + ESP + Data, disk1: Data
+/// - BtrfsRaid1: need at least 2 disks; disk0: BIOS (opt) + ESP + Data, disk1: Data
+/// - SsdHddBcachefs: need >=1 SSD (rotational=false) and >=1 HDD (rotational=true);
+///     SSD: BIOS (opt) + ESP + Cache; HDD: Data
 pub fn plan_partitions(disks: &[Disk], cfg: &Config) -> Result<PartitionPlan> {
     let align = cfg.partitioning.alignment_mib;
     let require_empty = cfg.partitioning.require_empty_disks;
@@ -138,7 +138,9 @@ pub fn plan_partitions(disks: &[Disk], cfg: &Config) -> Result<PartitionPlan> {
     let add_bios = cfg.partitioning.bios_boot.enabled && !is_efi_boot();
 
     if disks.is_empty() {
-        return Err(Error::Partition("no disks provided to partition planner".into()));
+        return Err(Error::Partition(
+            "no disks provided to partition planner".into(),
+        ));
     }
 
     let mut plans: Vec<DiskPlan> = Vec::new();
@@ -164,7 +166,10 @@ pub fn plan_partitions(disks: &[Disk], cfg: &Config) -> Result<PartitionPlan> {
                 size_mib: None,
                 gpt_name: cfg.partitioning.data.gpt_name.clone(),
             });
-            plans.push(DiskPlan { disk: d0.clone(), parts });
+            plans.push(DiskPlan {
+                disk: d0.clone(),
+                parts,
+            });
         }
         Topology::BcachefsSingle => {
             let d0 = &disks[0];
@@ -186,11 +191,16 @@ pub fn plan_partitions(disks: &[Disk], cfg: &Config) -> Result<PartitionPlan> {
                 size_mib: None,
                 gpt_name: cfg.partitioning.data.gpt_name.clone(),
             });
-            plans.push(DiskPlan { disk: d0.clone(), parts });
+            plans.push(DiskPlan {
+                disk: d0.clone(),
+                parts,
+            });
         }
         Topology::DualIndependent => {
             if disks.len() < 2 {
-                return Err(Error::Partition("DualIndependent topology requires at least 2 disks".into()));
+                return Err(Error::Partition(
+                    "DualIndependent topology requires at least 2 disks".into(),
+                ));
             }
             let d0 = &disks[0];
             let d1 = &disks[1];
@@ -214,7 +224,10 @@ pub fn plan_partitions(disks: &[Disk], cfg: &Config) -> Result<PartitionPlan> {
                 size_mib: None,
                 gpt_name: cfg.partitioning.data.gpt_name.clone(),
             });
-            plans.push(DiskPlan { disk: d0.clone(), parts: parts0 });
+            plans.push(DiskPlan {
+                disk: d0.clone(),
+                parts: parts0,
+            });
 
             // Disk 1: Data only
             let mut parts1 = Vec::new();
@@ -223,11 +236,16 @@ pub fn plan_partitions(disks: &[Disk], cfg: &Config) -> Result<PartitionPlan> {
                 size_mib: None,
                 gpt_name: cfg.partitioning.data.gpt_name.clone(),
             });
-            plans.push(DiskPlan { disk: d1.clone(), parts: parts1 });
+            plans.push(DiskPlan {
+                disk: d1.clone(),
+                parts: parts1,
+            });
         }
         Topology::BtrfsRaid1 => {
             if disks.len() < 2 {
-                return Err(Error::Partition("BtrfsRaid1 topology requires at least 2 disks".into()));
+                return Err(Error::Partition(
+                    "BtrfsRaid1 topology requires at least 2 disks".into(),
+                ));
             }
             let d0 = &disks[0];
             let d1 = &disks[1];
@@ -251,7 +269,10 @@ pub fn plan_partitions(disks: &[Disk], cfg: &Config) -> Result<PartitionPlan> {
                 size_mib: None,
                 gpt_name: cfg.partitioning.data.gpt_name.clone(),
             });
-            plans.push(DiskPlan { disk: d0.clone(), parts: parts0 });
+            plans.push(DiskPlan {
+                disk: d0.clone(),
+                parts: parts0,
+            });
 
             // Disk 1: Data only (for RAID1)
             let mut parts1 = Vec::new();
@@ -260,11 +281,16 @@ pub fn plan_partitions(disks: &[Disk], cfg: &Config) -> Result<PartitionPlan> {
                 size_mib: None,
                 gpt_name: cfg.partitioning.data.gpt_name.clone(),
             });
-            plans.push(DiskPlan { disk: d1.clone(), parts: parts1 });
+            plans.push(DiskPlan {
+                disk: d1.clone(),
+                parts: parts1,
+            });
         }
         Topology::Bcachefs2Copy => {
             if disks.len() < 2 {
-                return Err(Error::Partition("Bcachefs2Copy topology requires at least 2 disks".into()));
+                return Err(Error::Partition(
+                    "Bcachefs2Copy topology requires at least 2 disks".into(),
+                ));
             }
             let d0 = &disks[0];
             let d1 = &disks[1];
@@ -288,7 +314,10 @@ pub fn plan_partitions(disks: &[Disk], cfg: &Config) -> Result<PartitionPlan> {
                 size_mib: None,
                 gpt_name: cfg.partitioning.data.gpt_name.clone(),
             });
-            plans.push(DiskPlan { disk: d0.clone(), parts: parts0 });
+            plans.push(DiskPlan {
+                disk: d0.clone(),
+                parts: parts0,
+            });
 
             // Disk 1: Data only
             let mut parts1 = Vec::new();
@@ -297,14 +326,19 @@ pub fn plan_partitions(disks: &[Disk], cfg: &Config) -> Result<PartitionPlan> {
                 size_mib: None,
                 gpt_name: cfg.partitioning.data.gpt_name.clone(),
             });
-            plans.push(DiskPlan { disk: d1.clone(), parts: parts1 });
+            plans.push(DiskPlan {
+                disk: d1.clone(),
+                parts: parts1,
+            });
         }
         Topology::SsdHddBcachefs => {
             // Choose SSD (rotational=false) and HDD (rotational=true)
-            let ssd = disks.iter().find(|d| !d.rotational)
-                .ok_or_else(|| Error::Partition("SsdHddBcachefs requires an SSD (non-rotational) disk".into()))?;
-            let hdd = disks.iter().find(|d| d.rotational)
-                .ok_or_else(|| Error::Partition("SsdHddBcachefs requires an HDD (rotational) disk".into()))?;
+            let ssd = disks.iter().find(|d| !d.rotational).ok_or_else(|| {
+                Error::Partition("SsdHddBcachefs requires an SSD (non-rotational) disk".into())
+            })?;
+            let hdd = disks.iter().find(|d| d.rotational).ok_or_else(|| {
+                Error::Partition("SsdHddBcachefs requires an HDD (rotational) disk".into())
+            })?;
 
             // SSD: BIOS (opt) + ESP + Cache remainder
             let mut parts_ssd = Vec::new();
@@ -325,7 +359,10 @@ pub fn plan_partitions(disks: &[Disk], cfg: &Config) -> Result<PartitionPlan> {
                 size_mib: None,
                 gpt_name: cfg.partitioning.cache.gpt_name.clone(),
             });
-            plans.push(DiskPlan { disk: ssd.clone(), parts: parts_ssd });
+            plans.push(DiskPlan {
+                disk: ssd.clone(),
+                parts: parts_ssd,
+            });
 
             // HDD: Data remainder
             let mut parts_hdd = Vec::new();
@@ -334,7 +371,10 @@ pub fn plan_partitions(disks: &[Disk], cfg: &Config) -> Result<PartitionPlan> {
                 size_mib: None,
                 gpt_name: cfg.partitioning.data.gpt_name.clone(),
             });
-            plans.push(DiskPlan { disk: hdd.clone(), parts: parts_hdd });
+            plans.push(DiskPlan {
+                disk: hdd.clone(),
+                parts: parts_hdd,
+            });
         }
     }
 
@@ -389,10 +429,17 @@ pub fn apply_partitions(plan: &PartitionPlan) -> Result<Vec<PartitionResult>> {
         if let Some(blockdev) = which_tool("blockdev")? {
             let out = run_cmd_capture(&[blockdev.as_str(), "--getss", disk_path])?;
             let s = out.stdout.trim();
-            return s.parse::<u64>()
-                .map_err(|e| Error::Partition(format!("failed to parse sector size from blockdev for {}: {}", disk_path, e)));
+            return s.parse::<u64>().map_err(|e| {
+                Error::Partition(format!(
+                    "failed to parse sector size from blockdev for {}: {}",
+                    disk_path, e
+                ))
+            });
         }
-        warn!("blockdev not found; assuming 512-byte sectors for {}", disk_path);
+        warn!(
+            "blockdev not found; assuming 512-byte sectors for {}",
+            disk_path
+        );
         Ok(512)
     }
 
@@ -410,20 +457,29 @@ pub fn apply_partitions(plan: &PartitionPlan) -> Result<Vec<PartitionResult>> {
                 // Format: "First sector: 2048 (at 1024.0 KiB)"
                 let val = rest.trim().split_whitespace().next().unwrap_or("");
                 if !val.is_empty() {
-                    first = Some(val.parse::<u64>().map_err(|e| Error::Partition(format!("parse first sector: {}", e)))?);
+                    first = Some(
+                        val.parse::<u64>()
+                            .map_err(|e| Error::Partition(format!("parse first sector: {}", e)))?,
+                    );
                 }
             } else if let Some(rest) = line.strip_prefix("Last sector:") {
                 let val = rest.trim().split_whitespace().next().unwrap_or("");
                 if !val.is_empty() {
-                    last = Some(val.parse::<u64>().map_err(|e| Error::Partition(format!("parse last sector: {}", e)))?);
+                    last = Some(
+                        val.parse::<u64>()
+                            .map_err(|e| Error::Partition(format!("parse last sector: {}", e)))?,
+                    );
                 }
             }
         }
 
-        let first = first.ok_or_else(|| Error::Partition("sgdisk -i missing First sector".into()))?;
+        let first =
+            first.ok_or_else(|| Error::Partition("sgdisk -i missing First sector".into()))?;
         let last = last.ok_or_else(|| Error::Partition("sgdisk -i missing Last sector".into()))?;
         if guid.is_empty() {
-            return Err(Error::Partition("sgdisk -i missing Partition unique GUID".into()));
+            return Err(Error::Partition(
+                "sgdisk -i missing Partition unique GUID".into(),
+            ));
         }
         Ok((guid, first, last))
     }
@@ -467,9 +523,12 @@ pub fn apply_partitions(plan: &PartitionPlan) -> Result<Vec<PartitionResult>> {
 
             run_cmd(&[
                 sgdisk.as_str(),
-                "-n", n_arg.as_str(),
-                "-t", t_arg.as_str(),
-                "-c", c_arg.as_str(),
+                "-n",
+                n_arg.as_str(),
+                "-t",
+                t_arg.as_str(),
+                "-c",
+                c_arg.as_str(),
                 disk_path,
             ])?;
         }
@@ -486,11 +545,7 @@ pub fn apply_partitions(plan: &PartitionPlan) -> Result<Vec<PartitionResult>> {
 
             // Query sgdisk for partition info
             let i_arg = format!("{}", part_num);
-            let info_out = run_cmd_capture(&[
-                sgdisk.as_str(),
-                "-i", i_arg.as_str(),
-                disk_path,
-            ])?;
+            let info_out = run_cmd_capture(&[sgdisk.as_str(), "-i", i_arg.as_str(), disk_path])?;
 
             let (unique_guid, first_sector, last_sector) = parse_sgdisk_info(&info_out.stdout)?;
             let sectors = if last_sector >= first_sector {
@@ -516,6 +571,9 @@ pub fn apply_partitions(plan: &PartitionPlan) -> Result<Vec<PartitionResult>> {
         }
     }
 
-    debug!("apply_partitions: created {} partition entries", results.len());
+    debug!(
+        "apply_partitions: created {} partition entries",
+        results.len()
+    );
     Ok(results)
-}
\ No newline at end of file
+}
diff --git a/src/report/mod.rs b/src/report/mod.rs
index 3d12ef3..a99a943 100644
--- a/src/report/mod.rs
+++ b/src/report/mod.rs
@@ -9,4 +9,4 @@
 
 pub mod state;
 
-pub use state::*;
\ No newline at end of file
+pub use state::*;
diff --git a/src/report/state.rs b/src/report/state.rs
index b60012b..854208f 100644
--- a/src/report/state.rs
+++ b/src/report/state.rs
@@ -77,4 +77,4 @@ pub fn build_report(
 /// Write the state report JSON to disk (default path in config: /run/zosstorage/state.json).
 pub fn write_report(_report: &StateReport, _path: &str) -> Result<()> {
     todo!("serialize to JSON and persist atomically via tempfile and rename")
-}
\ No newline at end of file
+}
diff --git a/src/types.rs b/src/types.rs
index c8f3d28..d01632e 100644
--- a/src/types.rs
+++ b/src/types.rs
@@ -15,15 +15,15 @@
 // - Keep field names and enums stable; update docs/SCHEMA.md when public surface changes.
 // REGION: RESPONSIBILITIES-END
 
-use serde::{Deserialize, Serialize};
 use clap::ValueEnum;
+use serde::{Deserialize, Serialize};
 
 #[derive(Debug, Clone, Serialize, Deserialize)]
 pub struct LoggingConfig {
     /// Log level: "error" | "warn" | "info" | "debug"
-    pub level: String,     // default "info"
+    pub level: String, // default "info"
     /// When true, also log to /run/zosstorage/zosstorage.log
-    pub to_file: bool,     // default false
+    pub to_file: bool, // default false
 }
 
 #[derive(Debug, Clone, Serialize, Deserialize)]
@@ -55,7 +55,11 @@ pub enum Topology {
     #[value(alias = "ssd-hdd-bcachefs")]
     SsdHddBcachefs,
     /// Multi-device bcachefs with two replicas (data+metadata).
-    #[value(alias = "bcachefs2-copy", alias = "bcachefs-2copy", alias = "bcachefs-2-copy")]
+    #[value(
+        alias = "bcachefs2-copy",
+        alias = "bcachefs-2copy",
+        alias = "bcachefs-2-copy"
+    )]
     Bcachefs2Copy,
     /// Optional mirrored btrfs across two disks when explicitly requested.
     #[value(alias = "btrfs-raid1")]
@@ -205,4 +209,4 @@ pub struct Config {
     pub mount: MountScheme,
     /// Report output configuration.
     pub report: ReportOptions,
-}
\ No newline at end of file
+}
diff --git a/src/util/mod.rs b/src/util/mod.rs
index 3fc0eb4..a05068c 100644
--- a/src/util/mod.rs
+++ b/src/util/mod.rs
@@ -40,8 +40,8 @@
 //! and consistent error handling.
 
 use crate::{Error, Result};
-use std::process::Command;
 use std::path::Path;
+use std::process::Command;
 use tracing::{debug, warn};
 
 /// Captured output from an external tool invocation.
@@ -77,9 +77,10 @@ pub fn run_cmd(args: &[&str]) -> Result<()> {
         )));
     }
     debug!(target: "util.run_cmd", "exec: {:?}", args);
-    let output = Command::new(args[0]).args(&args[1..]).output().map_err(|e| {
-        Error::Other(anyhow::anyhow!("failed to spawn {:?}: {}", args, e))
-    })?;
+    let output = Command::new(args[0])
+        .args(&args[1..])
+        .output()
+        .map_err(|e| Error::Other(anyhow::anyhow!("failed to spawn {:?}: {}", args, e)))?;
 
     let status_code = output.status.code().unwrap_or(-1);
     if !output.status.success() {
@@ -103,9 +104,10 @@ pub fn run_cmd_capture(args: &[&str]) -> Result<CmdOutput> {
         )));
     }
     debug!(target: "util.run_cmd_capture", "exec: {:?}", args);
-    let output = Command::new(args[0]).args(&args[1..]).output().map_err(|e| {
-        Error::Other(anyhow::anyhow!("failed to spawn {:?}: {}", args, e))
-    })?;
+    let output = Command::new(args[0])
+        .args(&args[1..])
+        .output()
+        .map_err(|e| Error::Other(anyhow::anyhow!("failed to spawn {:?}: {}", args, e)))?;
     let status_code = output.status.code().unwrap_or(-1);
     let stdout = String::from_utf8_lossy(&output.stdout).to_string();
     let stderr = String::from_utf8_lossy(&output.stderr).to_string();
@@ -205,4 +207,4 @@ mod tests {
         // Should never fail even if udevadm is missing.
         udev_settle(1000).expect("udev_settle should be non-fatal");
     }
-}
\ No newline at end of file
+}