diff --git a/kmod/src/counters.h b/kmod/src/counters.h
index b8432d56..6d26c4f7 100644
--- a/kmod/src/counters.h
+++ b/kmod/src/counters.h
@@ -56,6 +56,7 @@
 	EXPAND_COUNTER(extent_delete)				\
 	EXPAND_COUNTER(extent_insert)				\
 	EXPAND_COUNTER(extent_next)				\
+	EXPAND_COUNTER(extent_prev)				\
 	EXPAND_COUNTER(extent_remove)				\
 	EXPAND_COUNTER(item_alloc)				\
 	EXPAND_COUNTER(item_batch_duplicate)			\
diff --git a/kmod/src/data.c b/kmod/src/data.c
index d2600cbe..50196f37 100644
--- a/kmod/src/data.c
+++ b/kmod/src/data.c
@@ -139,6 +139,7 @@ static int data_extent_io(struct super_block *sb, int op,
 {
 	struct scoutfs_lock *lock = data;
 	struct scoutfs_file_extent fex;
+	struct scoutfs_key first;
 	struct scoutfs_key last;
 	struct scoutfs_key key;
 	struct kvec val;
@@ -164,6 +165,7 @@ static int data_extent_io(struct super_block *sb, int op,
 	if (ext->type == SCOUTFS_FILE_EXTENT_TYPE) {
 		init_file_extent_key(&key, ext->owner,
 				     ext->start + ext->len - 1);
+		init_file_extent_key(&first, ext->owner, 0);
 		init_file_extent_key(&last, ext->owner, U64_MAX);
 		fex.blkno = cpu_to_le64(ext->map);
 		fex.len = cpu_to_le64(ext->len);
@@ -174,14 +176,20 @@ static int data_extent_io(struct super_block *sb, int op,
 				     ext->start + ext->len - 1, ext->len);
 		if (ext->type == SCOUTFS_FREE_EXTENT_BLOCKS_TYPE)
 			swap(key.sknf_major, key.sknf_minor);
+		init_free_extent_key(&first, ext->type, ext->owner,
+				     0, 0);
 		init_free_extent_key(&last, ext->type, ext->owner,
 				     U64_MAX, U64_MAX);
 		kvec_init(&val, NULL, 0);
 	}
 
-	if (op == SEI_NEXT) {
+	if (op == SEI_NEXT || op == SEI_PREV) {
 		expected = val.iov_len;
-		ret = scoutfs_item_next(sb, &key, &last, &val, lock);
+
+		if (op == SEI_NEXT)
+			ret = scoutfs_item_next(sb, &key, &last, &val, lock);
+		else
+			ret = scoutfs_item_prev(sb, &key, &first, &val, lock);
 		if (ret >= 0 && ret != expected)
 			ret = -EIO;
 		if (ret == expected)
diff --git a/kmod/src/extents.c b/kmod/src/extents.c
index bbb18c71..c5bacdfd 100644
--- a/kmod/src/extents.c
+++ b/kmod/src/extents.c
@@ -153,6 +153,19 @@ int scoutfs_extent_next(struct super_block *sb, scoutfs_extent_io_t iof,
 	return ret;
 }
 
+int scoutfs_extent_prev(struct super_block *sb, scoutfs_extent_io_t iof,
+			struct scoutfs_extent *ext, void *data)
+{
+	int ret;
+
+	scoutfs_inc_counter(sb, extent_prev);
+	trace_scoutfs_extent_prev_input(sb, ext);
+	ret = iof(sb, SEI_PREV, ext, data);
+	if (ret == 0)
+		trace_scoutfs_extent_prev_output(sb, ext);
+	return ret;
+}
+
 /*
  * Search for a next extent and see if we can merge it with the caller's
  * extent.  The caller has initialized next for us to search from.  If
diff --git a/kmod/src/extents.h b/kmod/src/extents.h
index d97f1f32..2cba23ab 100644
--- a/kmod/src/extents.h
+++ b/kmod/src/extents.h
@@ -20,6 +20,7 @@ struct scoutfs_extent {
 
 enum {
 	SEI_NEXT,
+	SEI_PREV,
 	SEI_INSERT,
 	SEI_DELETE,
 };
@@ -33,6 +34,8 @@ bool scoutfs_extent_intersection(struct scoutfs_extent *a,
 
 int scoutfs_extent_next(struct super_block *sb, scoutfs_extent_io_t iof,
 			struct scoutfs_extent *ext, void *data);
+int scoutfs_extent_prev(struct super_block *sb, scoutfs_extent_io_t iof,
+			struct scoutfs_extent *ext, void *data);
 int scoutfs_extent_add(struct super_block *sb, scoutfs_extent_io_t iof,
 		       struct scoutfs_extent *add, void *data);
 int scoutfs_extent_remove(struct super_block *sb, scoutfs_extent_io_t iof,
diff --git a/kmod/src/scoutfs_trace.h b/kmod/src/scoutfs_trace.h
index b665dbab..87495177 100644
--- a/kmod/src/scoutfs_trace.h
+++ b/kmod/src/scoutfs_trace.h
@@ -2222,6 +2222,14 @@ DEFINE_EVENT(scoutfs_extent_class, scoutfs_extent_next_output,
 	TP_PROTO(struct super_block *sb, struct scoutfs_extent *ext),
 	TP_ARGS(sb, ext)
 );
+DEFINE_EVENT(scoutfs_extent_class, scoutfs_extent_prev_input,
+	TP_PROTO(struct super_block *sb, struct scoutfs_extent *ext),
+	TP_ARGS(sb, ext)
+);
+DEFINE_EVENT(scoutfs_extent_class, scoutfs_extent_prev_output,
+	TP_PROTO(struct super_block *sb, struct scoutfs_extent *ext),
+	TP_ARGS(sb, ext)
+);
 DEFINE_EVENT(scoutfs_extent_class, scoutfs_extent_add,
 	TP_PROTO(struct super_block *sb, struct scoutfs_extent *ext),
 	TP_ARGS(sb, ext)
diff --git a/kmod/src/server.c b/kmod/src/server.c
index 1290f75b..d830d53e 100644
--- a/kmod/src/server.c
+++ b/kmod/src/server.c
@@ -164,9 +164,13 @@ static int server_extent_io(struct super_block *sb, int op,
 	if (ext->type == SCOUTFS_FREE_EXTENT_BLOCKS_TYPE)
 		swap(ebk.major, ebk.minor);
 
-	if (op == SEI_NEXT) {
-		ret = scoutfs_btree_next(sb, &super->alloc_root,
-					 &ebk, sizeof(ebk), &iref);
+	if (op == SEI_NEXT || op == SEI_PREV) {
+		if (op == SEI_NEXT)
+			ret = scoutfs_btree_next(sb, &super->alloc_root,
+						 &ebk, sizeof(ebk), &iref);
+		else
+			ret = scoutfs_btree_prev(sb, &super->alloc_root,
+						 &ebk, sizeof(ebk), &iref);
 		if (ret == 0) {
 			ret = init_extent_from_btree_key(ext, ext->type,
 							 iref.key,