[pbs-devel] [PATCH v2 proxmox-backup 01/15] tools: add disks utility functions

[Hannes Laimer <h.laimer@proxmox.com>]

adds:
 - get_fs_uuid_by_disk_path: taken out of the already existing
    get_fs_uuid function
 - get_mount_point_by_uuid: returns the mount-point of a disk by a given
    uuid, fails if the disk is not mounted
 - get_fs_uuid_by_path: finds the uuid of the disk that the given path
    is on, can fail if there is no uuid for the disk
 - mount_by_uuid: mounts a disk identified by uuid to a given path
 - unmount_by_mount_point: basically linux 'umount -l', justification
    for the lazy option in code
---
 src/tools/disks/mod.rs | 53 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 53 insertions(+)

diff --git a/src/tools/disks/mod.rs b/src/tools/disks/mod.rs
index af7f7fe1..ec4d8742 100644
--- a/src/tools/disks/mod.rs
+++ b/src/tools/disks/mod.rs
@@ -1009,6 +1009,22 @@ pub fn get_fs_uuid(disk: &Disk) -> Result<String, Error> {
         None => bail!("disk {:?} has no node in /dev", disk.syspath()),
     };
 
+    get_fs_uuid_by_disk_path(&disk_path)
+}
+
+/// Get the FS UUID of the disk that the given path is on.
+pub fn get_fs_uuid_by_path(path: &Path) -> Result<String, Error> {
+    let mut command = std::process::Command::new("df");
+    command.args(&["--output=source"]);
+    command.arg(path);
+
+    let output = crate::tools::run_command(command, None)?;
+
+    get_fs_uuid_by_disk_path(Path::new(output.lines().skip(1).next().unwrap()))
+}
+
+/// Get the FS UUID of a disk with a given disk path.
+pub fn get_fs_uuid_by_disk_path(disk_path: &Path) -> Result<String, Error> {
     let mut command = std::process::Command::new("blkid");
     command.args(&["-o", "export"]);
     command.arg(disk_path);
@@ -1023,3 +1039,40 @@ pub fn get_fs_uuid(disk: &Disk) -> Result<String, Error> {
 
     bail!("get_fs_uuid failed - missing UUID");
 }
+
+/// Get mount point by UUID
+pub fn get_mount_point_by_uuid(uuid: &str) -> Result<String, Error> {
+    let mut command = std::process::Command::new("findmnt");
+    command.args(&["-rn", "-oTARGET", "-S"]);
+    command.arg(&format!("UUID={}", uuid));
+
+    let output = crate::tools::run_command(command, None)?;
+
+    if !output.is_empty() {
+        return Ok(String::from(output.trim()));
+    }
+
+    bail!("get_mount_point_by_uuid failed - device with uuid: {} is not mounted", uuid);
+}
+
+/// Mount a disk by its UUID and the mount point.
+pub fn mount_by_uuid(uuid: &str, mount_point: &Path) -> Result<(), Error> {
+    let mut command = std::process::Command::new("mount");
+    command.args(&[&format!("UUID={}", uuid)]);
+    command.arg(mount_point);
+
+    crate::tools::run_command(command, None)?;
+    Ok(())
+}
+
+/// Unmount a disk by its mount point.
+pub fn unmount_by_mount_point(mount_point: &Path) -> Result<(), Error> {
+    let mut command = std::process::Command::new("umount");
+    // Datastores are only unmounted after a check for running jobs, '-l' needed due to some weird
+    // bug where some tokio-threads keep the .lock-file open (sometimes)
+    command.args(&["-l"]);
+    command.arg(mount_point);
+
+    crate::tools::run_command(command, None)?;
+    Ok(())
+}
-- 
2.30.2