DLPX-81523 test_repeated_reboots failed with core.zcachedb (openzfs#477)

Signed-off-by: Paul Dagnelie <pcd@delphix.com>

cmd/zfs_object_agent/zettacache/src/checkpoint.rs

@@ -1,5 +1,6 @@
 use std::time::Instant;
 
+use anyhow::Result;
 use futures::future;
 use futures::stream::FuturesOrdered;
 use futures::stream::StreamExt;
@@ -48,7 +49,7 @@ pub struct CheckpointPhys {
 }
 
 impl CheckpointPhys {
-    pub async fn read(block_access: &BlockAccess, extents: &[Extent]) -> Self {
+    pub async fn read(block_access: &BlockAccess, extents: &[Extent]) -> Result<Self> {
         let raw = extents
             .iter()
             .map(|&extent| block_access.read_raw(extent, DiskIoType::MaintenanceRead))
@@ -58,9 +59,9 @@ impl CheckpointPhys {
                 future::ready(vec)
             })
             .await;
-        let (this, _): (Self, usize) = block_access.chunk_from_raw(&raw).unwrap();
+        let (this, _) = block_access.chunk_from_raw(&raw)?;
         debug!("got {:#?}", this);
-        this
+        Ok(this)
     }
 
     pub async fn write(

cmd/zfs_object_agent/zettacache/src/zettacache/mod.rs

@@ -551,8 +551,7 @@ impl Inner {
         let (mut primary, primary_disk, guid, extra_disks) =
             PrimaryPhys::read(&block_access).await.unwrap();
 
-        // XXX proper error handling
-        let mut checkpoint = CheckpointPhys::read(&block_access, &primary.checkpoint).await;
+        let mut checkpoint = CheckpointPhys::read(&block_access, &primary.checkpoint).await?;
         assert_eq!(checkpoint.id, primary.checkpoint_id);
 
         let mut size_changed = false;

cmd/zfs_object_agent/zettacache/src/zettacache/zcdb.rs

@@ -54,7 +54,7 @@ impl ZCacheDBHandle {
         let block_access = Arc::new(BlockAccess::new(disks, true));
 
         let (primary, primary_disk, guid, _extra_disks) = PrimaryPhys::read(&block_access).await?;
-        let checkpoint = Arc::new(CheckpointPhys::read(&block_access, &primary.checkpoint).await);
+        let checkpoint = Arc::new(CheckpointPhys::read(&block_access, &primary.checkpoint).await?);
 
         let mut slab_builder = SlabAllocatorBuilder::new(checkpoint.slab_allocator.clone());
         // We should be able to get away without claiming the metadata space,