mount: Add inspect_filesystem_by_uuid

This patch adds a new function that identifies a filesystem by
partition UUID.

Signed-off-by: Yohei Ueda <yohei@jp.ibm.com>

lib/src/install.rs

@@ -1683,7 +1683,9 @@ fn test_gather_root_args() {
     // A basic filesystem using a UUID
     let inspect = Filesystem {
         source: "/dev/vda4".into(),
+        target: "/".into(),
         fstype: "xfs".into(),
+        maj_min: "252:4".into(),
         options: "rw".into(),
         uuid: Some("965eb3c7-5a3f-470d-aaa2-1bcf04334bc6".into()),
     };

lib/src/mount.rs

@@ -12,6 +12,9 @@ use crate::task::Task;
 pub(crate) struct Filesystem {
     // Note if you add an entry to this list, you need to change the --output invocation below too
     pub(crate) source: String,
+    pub(crate) target: String,
+    #[serde(rename = "maj:min")]
+    pub(crate) maj_min: String,
     pub(crate) fstype: String,
     pub(crate) options: String,
     pub(crate) uuid: Option<String>,
@@ -29,7 +32,7 @@ fn run_findmnt(args: &[&str], path: &str) -> Result<Filesystem> {
             "-J",
             "-v",
             // If you change this you probably also want to change the Filesystem struct above
-            "--output=SOURCE,FSTYPE,OPTIONS,UUID",
+            "--output=SOURCE,TARGET,MAJ:MIN,FSTYPE,OPTIONS,UUID",
         ])
         .args(args)
         .arg(path)
@@ -49,6 +52,12 @@ pub(crate) fn inspect_filesystem(path: &Utf8Path) -> Result<Filesystem> {
     run_findmnt(&["--mountpoint"], path.as_str())
 }
 
+#[context("Inspecting filesystem by UUID {uuid}")]
+/// Inspect a filesystem by partition UUID
+pub(crate) fn inspect_filesystem_by_uuid(uuid: &str) -> Result<Filesystem> {
+    run_findmnt(&["--source"], &(format!("UUID={uuid}")))
+}
+
 /// Mount a device to the target path.
 pub(crate) fn mount(dev: &str, target: &Utf8Path) -> Result<()> {
     Task::new_and_run(