api: datastore_status: restore api/gui compatibility

the latest changes to this api call changed/removed some things that
were actually necessary for the gui. Readd those and document them this
time.

The change from u64 to i64 limits us to 8EiB of Datastore sizes (instead if
16EiB) but if we reach that, we must adapt most other parts to use 128bit
sizes anyway

Signed-off-by: Dominik Csapak <d.csapak@proxmox.com>

pbs-api-types/src/datastore.rs

@@ -653,25 +653,30 @@ pub struct DataStoreStatus {
 /// Status of a Datastore
 pub struct DataStoreStatusListItem {
     pub store: String,
-    /// The Size of the underlying storage in bytes.
+    /// The Size of the underlying storage in bytes. (-1 on error)
-    pub total: u64,
+    pub total: i64,
-    /// The used bytes of the underlying storage.
+    /// The used bytes of the underlying storage. (-1 on error)
-    pub used: u64,
+    pub used: i64,
-    /// The available bytes of the underlying storage.
+    /// The available bytes of the underlying storage. (-1 on error)
-    pub avail: u64,
+    pub avail: i64,
     /// A list of usages of the past (last Month).
+    #[serde(skip_serializing_if="Option::is_none")]
     pub history: Option<Vec<Option<f64>>>,
     /// History start time (epoch)
+    #[serde(skip_serializing_if="Option::is_none")]
     pub history_start: Option<u64>,
     /// History resolution (seconds)
+    #[serde(skip_serializing_if="Option::is_none")]
     pub history_delta: Option<u64>,
     /// Estimation of the UNIX epoch when the storage will be full.
     /// This is calculated via a simple Linear Regression (Least
     /// Squares) of RRD data of the last Month. Missing if there are
     /// not enough data points yet. If the estimate lies in the past,
-    /// the usage is decreasing.
+    /// the usage is decreasing or not changing.
+    #[serde(skip_serializing_if="Option::is_none")]
     pub estimated_full_date: Option<i64>,
     /// An error description, for example, when the datastore could not be looked up
+    #[serde(skip_serializing_if="Option::is_none")]
     pub error: Option<String>,
 }
 

src/api2/status.rs

@@ -62,9 +62,9 @@ pub fn datastore_status(
             Err(err) => {
                 list.push(DataStoreStatusListItem {
                     store: store.clone(),
-                    total: 0,
+                    total: -1,
-                    used: 0,
+                    used: -1,
-                    avail: 0,
+                    avail: -1,
                     history: None,
                     history_start: None,
                     history_delta: None,
@@ -78,9 +78,9 @@ pub fn datastore_status(
 
         let mut entry = DataStoreStatusListItem {
             store: store.clone(),
-            total: status.total,
+            total: status.total as i64,
-            used: status.used,
+            used: status.used as i64,
-            avail: status.avail,
+            avail: status.avail as i64,
             history: None,
             history_start: None,
             history_delta: None,
@@ -133,6 +133,7 @@ pub fn datastore_status(
             if usage_list.len() >= 7 {
                 entry.estimated_full_date = match linear_regression(&time_list, &usage_list) {
                     Some((a, b)) if b != 0.0 => Some(((1.0 - a) / b).floor() as i64),
+                    Some((_, b)) if b == 0.0 => Some(0), // infinite estimate, set to past for gui to detect
                     _ => None,
                 };
             }