diff --git a/pageserver/src/import_datadir.rs b/pageserver/src/import_datadir.rs
index 936de35eb9..9ad0124a80 100644
--- a/pageserver/src/import_datadir.rs
+++ b/pageserver/src/import_datadir.rs
@@ -75,12 +75,12 @@ pub async fn import_timeline_from_postgres_datadir(
             {
                 pg_control = Some(control_file);
             }
-            modification.flush()?;
+            modification.flush().await?;
         }
     }
 
     // We're done importing all the data files.
-    modification.commit()?;
+    modification.commit().await?;
 
     // We expect the Postgres server to be shut down cleanly.
     let pg_control = pg_control.context("pg_control file not found")?;
@@ -359,7 +359,7 @@ pub async fn import_basebackup_from_tar(
                     // We found the pg_control file.
                     pg_control = Some(res);
                 }
-                modification.flush()?;
+                modification.flush().await?;
             }
             tokio_tar::EntryType::Directory => {
                 debug!("directory {:?}", file_path);
@@ -377,7 +377,7 @@ pub async fn import_basebackup_from_tar(
     // sanity check: ensure that pg_control is loaded
     let _pg_control = pg_control.context("pg_control file not found")?;
 
-    modification.commit()?;
+    modification.commit().await?;
     Ok(())
 }
 
@@ -594,7 +594,7 @@ async fn import_file(
         // zenith.signal is not necessarily the last file, that we handle
         // but it is ok to call `finish_write()`, because final `modification.commit()`
         // will update lsn once more to the final one.
-        let writer = modification.tline.writer();
+        let writer = modification.tline.writer().await;
         writer.finish_write(prev_lsn);
 
         debug!("imported zenith signal {}", prev_lsn);
diff --git a/pageserver/src/pgdatadir_mapping.rs b/pageserver/src/pgdatadir_mapping.rs
index 769d02af0b..188b5d15ce 100644
--- a/pageserver/src/pgdatadir_mapping.rs
+++ b/pageserver/src/pgdatadir_mapping.rs
@@ -1108,7 +1108,7 @@ impl<'a> DatadirModification<'a> {
     /// retains all the metadata, but data pages are flushed. That's again OK
     /// for bulk import, where you are just loading data pages and won't try to
     /// modify the same pages twice.
-    pub fn flush(&mut self) -> anyhow::Result<()> {
+    pub async fn flush(&mut self) -> anyhow::Result<()> {
         // Unless we have accumulated a decent amount of changes, it's not worth it
         // to scan through the pending_updates list.
         let pending_nblocks = self.pending_nblocks;
@@ -1116,7 +1116,7 @@ impl<'a> DatadirModification<'a> {
             return Ok(());
         }
 
-        let writer = self.tline.writer();
+        let writer = self.tline.writer().await;
 
         let mut layer_map = self.tline.layers.write().unwrap();
 
@@ -1145,8 +1145,8 @@ impl<'a> DatadirModification<'a> {
     /// underlying timeline.
     /// All the modifications in this atomic update are stamped by the specified LSN.
     ///
-    pub fn commit(&mut self) -> anyhow::Result<()> {
-        let writer = self.tline.writer();
+    pub async fn commit(&mut self) -> anyhow::Result<()> {
+        let writer = self.tline.writer().await;
         let lsn = self.lsn;
         let pending_nblocks = self.pending_nblocks;
         self.pending_nblocks = 0;
@@ -1596,7 +1596,7 @@ fn is_slru_block_key(key: Key) -> bool {
 }
 
 #[cfg(test)]
-pub fn create_test_timeline(
+pub async fn create_test_timeline(
     tenant: &crate::tenant::Tenant,
     timeline_id: utils::id::TimelineId,
     pg_version: u32,
@@ -1605,7 +1605,7 @@ pub fn create_test_timeline(
     let tline = tenant.create_test_timeline(timeline_id, Lsn(8), pg_version, ctx)?;
     let mut m = tline.begin_modification(Lsn(8));
     m.init_empty()?;
-    m.commit()?;
+    m.commit().await?;
     Ok(tline)
 }
 
diff --git a/pageserver/src/tenant.rs b/pageserver/src/tenant.rs
index c5d9cbf03d..8aac7d869a 100644
--- a/pageserver/src/tenant.rs
+++ b/pageserver/src/tenant.rs
@@ -3326,12 +3326,12 @@ mod tests {
         let (tenant, ctx) = TenantHarness::create("test_basic")?.load().await;
         let tline = tenant.create_test_timeline(TIMELINE_ID, Lsn(0), DEFAULT_PG_VERSION, &ctx)?;
 
-        let writer = tline.writer();
+        let writer = tline.writer().await;
         writer.put(*TEST_KEY, Lsn(0x10), &Value::Image(TEST_IMG("foo at 0x10")))?;
         writer.finish_write(Lsn(0x10));
         drop(writer);
 
-        let writer = tline.writer();
+        let writer = tline.writer().await;
         writer.put(*TEST_KEY, Lsn(0x20), &Value::Image(TEST_IMG("foo at 0x20")))?;
         writer.finish_write(Lsn(0x20));
         drop(writer);
@@ -3389,7 +3389,7 @@ mod tests {
 
         let (tenant, ctx) = TenantHarness::create("test_branch")?.load().await;
         let tline = tenant.create_test_timeline(TIMELINE_ID, Lsn(0), DEFAULT_PG_VERSION, &ctx)?;
-        let writer = tline.writer();
+        let writer = tline.writer().await;
 
         #[allow(non_snake_case)]
         let TEST_KEY_A: Key = Key::from_hex("112222222233333333444444445500000001").unwrap();
@@ -3415,7 +3415,7 @@ mod tests {
         let newtline = tenant
             .get_timeline(NEW_TIMELINE_ID, true)
             .expect("Should have a local timeline");
-        let new_writer = newtline.writer();
+        let new_writer = newtline.writer().await;
         new_writer.put(TEST_KEY_A, Lsn(0x40), &test_value("bar at 0x40"))?;
         new_writer.finish_write(Lsn(0x40));
 
@@ -3442,7 +3442,7 @@ mod tests {
         let mut lsn = start_lsn;
         #[allow(non_snake_case)]
         {
-            let writer = tline.writer();
+            let writer = tline.writer().await;
             // Create a relation on the timeline
             writer.put(
                 *TEST_KEY,
@@ -3461,7 +3461,7 @@ mod tests {
         }
         tline.freeze_and_flush().await?;
         {
-            let writer = tline.writer();
+            let writer = tline.writer().await;
             writer.put(
                 *TEST_KEY,
                 lsn,
@@ -3773,7 +3773,7 @@ mod tests {
         let (tenant, ctx) = TenantHarness::create("test_images")?.load().await;
         let tline = tenant.create_test_timeline(TIMELINE_ID, Lsn(0), DEFAULT_PG_VERSION, &ctx)?;
 
-        let writer = tline.writer();
+        let writer = tline.writer().await;
         writer.put(*TEST_KEY, Lsn(0x10), &Value::Image(TEST_IMG("foo at 0x10")))?;
         writer.finish_write(Lsn(0x10));
         drop(writer);
@@ -3781,7 +3781,7 @@ mod tests {
         tline.freeze_and_flush().await?;
         tline.compact(&ctx).await?;
 
-        let writer = tline.writer();
+        let writer = tline.writer().await;
         writer.put(*TEST_KEY, Lsn(0x20), &Value::Image(TEST_IMG("foo at 0x20")))?;
         writer.finish_write(Lsn(0x20));
         drop(writer);
@@ -3789,7 +3789,7 @@ mod tests {
         tline.freeze_and_flush().await?;
         tline.compact(&ctx).await?;
 
-        let writer = tline.writer();
+        let writer = tline.writer().await;
         writer.put(*TEST_KEY, Lsn(0x30), &Value::Image(TEST_IMG("foo at 0x30")))?;
         writer.finish_write(Lsn(0x30));
         drop(writer);
@@ -3797,7 +3797,7 @@ mod tests {
         tline.freeze_and_flush().await?;
         tline.compact(&ctx).await?;
 
-        let writer = tline.writer();
+        let writer = tline.writer().await;
         writer.put(*TEST_KEY, Lsn(0x40), &Value::Image(TEST_IMG("foo at 0x40")))?;
         writer.finish_write(Lsn(0x40));
         drop(writer);
@@ -3847,7 +3847,7 @@ mod tests {
         for _ in 0..50 {
             for _ in 0..10000 {
                 test_key.field6 = blknum;
-                let writer = tline.writer();
+                let writer = tline.writer().await;
                 writer.put(
                     test_key,
                     lsn,
@@ -3895,7 +3895,7 @@ mod tests {
         for blknum in 0..NUM_KEYS {
             lsn = Lsn(lsn.0 + 0x10);
             test_key.field6 = blknum as u32;
-            let writer = tline.writer();
+            let writer = tline.writer().await;
             writer.put(
                 test_key,
                 lsn,
@@ -3913,7 +3913,7 @@ mod tests {
                 lsn = Lsn(lsn.0 + 0x10);
                 let blknum = thread_rng().gen_range(0..NUM_KEYS);
                 test_key.field6 = blknum as u32;
-                let writer = tline.writer();
+                let writer = tline.writer().await;
                 writer.put(
                     test_key,
                     lsn,
@@ -3969,7 +3969,7 @@ mod tests {
         for blknum in 0..NUM_KEYS {
             lsn = Lsn(lsn.0 + 0x10);
             test_key.field6 = blknum as u32;
-            let writer = tline.writer();
+            let writer = tline.writer().await;
             writer.put(
                 test_key,
                 lsn,
@@ -3995,7 +3995,7 @@ mod tests {
                 lsn = Lsn(lsn.0 + 0x10);
                 let blknum = thread_rng().gen_range(0..NUM_KEYS);
                 test_key.field6 = blknum as u32;
-                let writer = tline.writer();
+                let writer = tline.writer().await;
                 writer.put(
                     test_key,
                     lsn,
@@ -4060,7 +4060,7 @@ mod tests {
                 lsn = Lsn(lsn.0 + 0x10);
                 let blknum = thread_rng().gen_range(0..NUM_KEYS);
                 test_key.field6 = blknum as u32;
-                let writer = tline.writer();
+                let writer = tline.writer().await;
                 writer.put(
                     test_key,
                     lsn,
diff --git a/pageserver/src/tenant/timeline.rs b/pageserver/src/tenant/timeline.rs
index 763e159849..45ed18aebd 100644
--- a/pageserver/src/tenant/timeline.rs
+++ b/pageserver/src/tenant/timeline.rs
@@ -28,7 +28,7 @@ use std::ops::{Deref, Range};
 use std::path::{Path, PathBuf};
 use std::pin::pin;
 use std::sync::atomic::{AtomicI64, Ordering as AtomicOrdering};
-use std::sync::{Arc, Mutex, MutexGuard, RwLock, Weak};
+use std::sync::{Arc, Mutex, RwLock, Weak};
 use std::time::{Duration, Instant, SystemTime};
 
 use crate::context::{DownloadBehavior, RequestContext};
@@ -179,7 +179,7 @@ pub struct Timeline {
     /// Locked automatically by [`TimelineWriter`] and checkpointer.
     /// Must always be acquired before the layer map/individual layer lock
     /// to avoid deadlock.
-    write_lock: Mutex<()>,
+    write_lock: tokio::sync::Mutex<()>,
 
     /// Used to avoid multiple `flush_loop` tasks running
     flush_loop_state: Mutex<FlushLoopState>,
@@ -666,7 +666,7 @@ impl Timeline {
     /// Flush to disk all data that was written with the put_* functions
     #[instrument(skip(self), fields(tenant_id=%self.tenant_id, timeline_id=%self.timeline_id))]
     pub async fn freeze_and_flush(&self) -> anyhow::Result<()> {
-        self.freeze_inmem_layer(false);
+        self.freeze_inmem_layer(false).await;
         self.flush_frozen_layers_and_wait().await
     }
 
@@ -846,10 +846,10 @@ impl Timeline {
     }
 
     /// Mutate the timeline with a [`TimelineWriter`].
-    pub fn writer(&self) -> TimelineWriter<'_> {
+    pub async fn writer(&self) -> TimelineWriter<'_> {
         TimelineWriter {
             tl: self,
-            _write_guard: self.write_lock.lock().unwrap(),
+            _write_guard: self.write_lock.lock().await,
         }
     }
 
@@ -883,7 +883,7 @@ impl Timeline {
     ///
     /// Also flush after a period of time without new data -- it helps
     /// safekeepers to regard pageserver as caught up and suspend activity.
-    pub fn check_checkpoint_distance(self: &Arc<Timeline>) -> anyhow::Result<()> {
+    pub async fn check_checkpoint_distance(self: &Arc<Timeline>) -> anyhow::Result<()> {
         let last_lsn = self.get_last_record_lsn();
         let layers = self.layers.read().unwrap();
         if let Some(open_layer) = &layers.open_layer {
@@ -907,7 +907,7 @@ impl Timeline {
                     last_freeze_ts.elapsed()
                 );
 
-                self.freeze_inmem_layer(true);
+                self.freeze_inmem_layer(true).await;
                 self.last_freeze_at.store(last_lsn);
                 *(self.last_freeze_ts.write().unwrap()) = Instant::now();
 
@@ -1381,7 +1381,7 @@ impl Timeline {
                 layer_flush_start_tx,
                 layer_flush_done_tx,
 
-                write_lock: Mutex::new(()),
+                write_lock: tokio::sync::Mutex::new(()),
                 layer_removal_cs: Default::default(),
 
                 gc_info: std::sync::RwLock::new(GcInfo {
@@ -2627,13 +2627,13 @@ impl Timeline {
         self.last_record_lsn.advance(new_lsn);
     }
 
-    fn freeze_inmem_layer(&self, write_lock_held: bool) {
+    async fn freeze_inmem_layer(&self, write_lock_held: bool) {
         // Freeze the current open in-memory layer. It will be written to disk on next
         // iteration.
         let _write_guard = if write_lock_held {
             None
         } else {
-            Some(self.write_lock.lock().unwrap())
+            Some(self.write_lock.lock().await)
         };
         let mut layers = self.layers.write().unwrap();
         if let Some(open_layer) = &layers.open_layer {
@@ -4434,7 +4434,7 @@ fn layer_traversal_error(msg: String, path: Vec<TraversalPathItem>) -> PageRecon
 // but will cause large code changes.
 pub struct TimelineWriter<'a> {
     tl: &'a Timeline,
-    _write_guard: MutexGuard<'a, ()>,
+    _write_guard: tokio::sync::MutexGuard<'a, ()>,
 }
 
 impl Deref for TimelineWriter<'_> {
diff --git a/pageserver/src/tenant/timeline/walreceiver/walreceiver_connection.rs b/pageserver/src/tenant/timeline/walreceiver/walreceiver_connection.rs
index 1cbed3416c..91ff60603a 100644
--- a/pageserver/src/tenant/timeline/walreceiver/walreceiver_connection.rs
+++ b/pageserver/src/tenant/timeline/walreceiver/walreceiver_connection.rs
@@ -313,12 +313,15 @@ pub(super) async fn handle_walreceiver_connection(
             }
         }
 
-        timeline.check_checkpoint_distance().with_context(|| {
-            format!(
-                "Failed to check checkpoint distance for timeline {}",
-                timeline.timeline_id
-            )
-        })?;
+        timeline
+            .check_checkpoint_distance()
+            .await
+            .with_context(|| {
+                format!(
+                    "Failed to check checkpoint distance for timeline {}",
+                    timeline.timeline_id
+                )
+            })?;
 
         if let Some(last_lsn) = status_update {
             let timeline_remote_consistent_lsn =
diff --git a/pageserver/src/walingest.rs b/pageserver/src/walingest.rs
index 4b8e6aa515..fc0cc5c81e 100644
--- a/pageserver/src/walingest.rs
+++ b/pageserver/src/walingest.rs
@@ -333,7 +333,7 @@ impl<'a> WalIngest<'a> {
 
         // Now that this record has been fully handled, including updating the
         // checkpoint data, let the repository know that it is up-to-date to this LSN
-        modification.commit()?;
+        modification.commit().await?;
 
         Ok(())
     }
@@ -1200,7 +1200,7 @@ mod tests {
         let mut m = tline.begin_modification(Lsn(0x10));
         m.put_checkpoint(ZERO_CHECKPOINT.clone())?;
         m.put_relmap_file(0, 111, Bytes::from(""), ctx).await?; // dummy relmapper file
-        m.commit()?;
+        m.commit().await?;
         let walingest = WalIngest::new(tline, Lsn(0x10), ctx).await?;
 
         Ok(walingest)
@@ -1209,7 +1209,7 @@ mod tests {
     #[tokio::test]
     async fn test_relsize() -> Result<()> {
         let (tenant, ctx) = TenantHarness::create("test_relsize")?.load().await;
-        let tline = create_test_timeline(&tenant, TIMELINE_ID, DEFAULT_PG_VERSION, &ctx)?;
+        let tline = create_test_timeline(&tenant, TIMELINE_ID, DEFAULT_PG_VERSION, &ctx).await?;
         let mut walingest = init_walingest_test(&tline, &ctx).await?;
 
         let mut m = tline.begin_modification(Lsn(0x20));
@@ -1217,22 +1217,22 @@ mod tests {
         walingest
             .put_rel_page_image(&mut m, TESTREL_A, 0, TEST_IMG("foo blk 0 at 2"), &ctx)
             .await?;
-        m.commit()?;
+        m.commit().await?;
         let mut m = tline.begin_modification(Lsn(0x30));
         walingest
             .put_rel_page_image(&mut m, TESTREL_A, 0, TEST_IMG("foo blk 0 at 3"), &ctx)
             .await?;
-        m.commit()?;
+        m.commit().await?;
         let mut m = tline.begin_modification(Lsn(0x40));
         walingest
             .put_rel_page_image(&mut m, TESTREL_A, 1, TEST_IMG("foo blk 1 at 4"), &ctx)
             .await?;
-        m.commit()?;
+        m.commit().await?;
         let mut m = tline.begin_modification(Lsn(0x50));
         walingest
             .put_rel_page_image(&mut m, TESTREL_A, 2, TEST_IMG("foo blk 2 at 5"), &ctx)
             .await?;
-        m.commit()?;
+        m.commit().await?;
 
         assert_current_logical_size(&tline, Lsn(0x50));
 
@@ -1318,7 +1318,7 @@ mod tests {
         walingest
             .put_rel_truncation(&mut m, TESTREL_A, 2, &ctx)
             .await?;
-        m.commit()?;
+        m.commit().await?;
         assert_current_logical_size(&tline, Lsn(0x60));
 
         // Check reported size and contents after truncation
@@ -1360,7 +1360,7 @@ mod tests {
         walingest
             .put_rel_truncation(&mut m, TESTREL_A, 0, &ctx)
             .await?;
-        m.commit()?;
+        m.commit().await?;
         assert_eq!(
             tline
                 .get_rel_size(TESTREL_A, Lsn(0x68), false, &ctx)
@@ -1373,7 +1373,7 @@ mod tests {
         walingest
             .put_rel_page_image(&mut m, TESTREL_A, 1, TEST_IMG("foo blk 1"), &ctx)
             .await?;
-        m.commit()?;
+        m.commit().await?;
         assert_eq!(
             tline
                 .get_rel_size(TESTREL_A, Lsn(0x70), false, &ctx)
@@ -1398,7 +1398,7 @@ mod tests {
         walingest
             .put_rel_page_image(&mut m, TESTREL_A, 1500, TEST_IMG("foo blk 1500"), &ctx)
             .await?;
-        m.commit()?;
+        m.commit().await?;
         assert_eq!(
             tline
                 .get_rel_size(TESTREL_A, Lsn(0x80), false, &ctx)
@@ -1428,14 +1428,14 @@ mod tests {
     #[tokio::test]
     async fn test_drop_extend() -> Result<()> {
         let (tenant, ctx) = TenantHarness::create("test_drop_extend")?.load().await;
-        let tline = create_test_timeline(&tenant, TIMELINE_ID, DEFAULT_PG_VERSION, &ctx)?;
+        let tline = create_test_timeline(&tenant, TIMELINE_ID, DEFAULT_PG_VERSION, &ctx).await?;
         let mut walingest = init_walingest_test(&tline, &ctx).await?;
 
         let mut m = tline.begin_modification(Lsn(0x20));
         walingest
             .put_rel_page_image(&mut m, TESTREL_A, 0, TEST_IMG("foo blk 0 at 2"), &ctx)
             .await?;
-        m.commit()?;
+        m.commit().await?;
 
         // Check that rel exists and size is correct
         assert_eq!(
@@ -1454,7 +1454,7 @@ mod tests {
         // Drop rel
         let mut m = tline.begin_modification(Lsn(0x30));
         walingest.put_rel_drop(&mut m, TESTREL_A, &ctx).await?;
-        m.commit()?;
+        m.commit().await?;
 
         // Check that rel is not visible anymore
         assert_eq!(
@@ -1472,7 +1472,7 @@ mod tests {
         walingest
             .put_rel_page_image(&mut m, TESTREL_A, 0, TEST_IMG("foo blk 0 at 4"), &ctx)
             .await?;
-        m.commit()?;
+        m.commit().await?;
 
         // Check that rel exists and size is correct
         assert_eq!(
@@ -1497,7 +1497,7 @@ mod tests {
     #[tokio::test]
     async fn test_truncate_extend() -> Result<()> {
         let (tenant, ctx) = TenantHarness::create("test_truncate_extend")?.load().await;
-        let tline = create_test_timeline(&tenant, TIMELINE_ID, DEFAULT_PG_VERSION, &ctx)?;
+        let tline = create_test_timeline(&tenant, TIMELINE_ID, DEFAULT_PG_VERSION, &ctx).await?;
         let mut walingest = init_walingest_test(&tline, &ctx).await?;
 
         // Create a 20 MB relation (the size is arbitrary)
@@ -1509,7 +1509,7 @@ mod tests {
                 .put_rel_page_image(&mut m, TESTREL_A, blkno, TEST_IMG(&data), &ctx)
                 .await?;
         }
-        m.commit()?;
+        m.commit().await?;
 
         // The relation was created at LSN 20, not visible at LSN 1 yet.
         assert_eq!(
@@ -1554,7 +1554,7 @@ mod tests {
         walingest
             .put_rel_truncation(&mut m, TESTREL_A, 1, &ctx)
             .await?;
-        m.commit()?;
+        m.commit().await?;
 
         // Check reported size and contents after truncation
         assert_eq!(
@@ -1603,7 +1603,7 @@ mod tests {
                 .put_rel_page_image(&mut m, TESTREL_A, blkno, TEST_IMG(&data), &ctx)
                 .await?;
         }
-        m.commit()?;
+        m.commit().await?;
 
         assert_eq!(
             tline
@@ -1637,7 +1637,7 @@ mod tests {
     #[tokio::test]
     async fn test_large_rel() -> Result<()> {
         let (tenant, ctx) = TenantHarness::create("test_large_rel")?.load().await;
-        let tline = create_test_timeline(&tenant, TIMELINE_ID, DEFAULT_PG_VERSION, &ctx)?;
+        let tline = create_test_timeline(&tenant, TIMELINE_ID, DEFAULT_PG_VERSION, &ctx).await?;
         let mut walingest = init_walingest_test(&tline, &ctx).await?;
 
         let mut lsn = 0x10;
@@ -1648,7 +1648,7 @@ mod tests {
             walingest
                 .put_rel_page_image(&mut m, TESTREL_A, blknum as BlockNumber, img, &ctx)
                 .await?;
-            m.commit()?;
+            m.commit().await?;
         }
 
         assert_current_logical_size(&tline, Lsn(lsn));
@@ -1664,7 +1664,7 @@ mod tests {
         walingest
             .put_rel_truncation(&mut m, TESTREL_A, RELSEG_SIZE, &ctx)
             .await?;
-        m.commit()?;
+        m.commit().await?;
         assert_eq!(
             tline.get_rel_size(TESTREL_A, Lsn(lsn), false, &ctx).await?,
             RELSEG_SIZE
@@ -1677,7 +1677,7 @@ mod tests {
         walingest
             .put_rel_truncation(&mut m, TESTREL_A, RELSEG_SIZE - 1, &ctx)
             .await?;
-        m.commit()?;
+        m.commit().await?;
         assert_eq!(
             tline.get_rel_size(TESTREL_A, Lsn(lsn), false, &ctx).await?,
             RELSEG_SIZE - 1
@@ -1693,7 +1693,7 @@ mod tests {
             walingest
                 .put_rel_truncation(&mut m, TESTREL_A, size as BlockNumber, &ctx)
                 .await?;
-            m.commit()?;
+            m.commit().await?;
             assert_eq!(
                 tline.get_rel_size(TESTREL_A, Lsn(lsn), false, &ctx).await?,
                 size as BlockNumber