From afb43b1641d0f4f218cfd76b2e2970b9dc60c95f Mon Sep 17 00:00:00 2001
From: Samuel Just <sjust@redhat.com>
Date: Thu, 4 Mar 2021 01:04:22 -0800
Subject: [PATCH] crimson/os/seastore/transaction_manager: expose find_hole

Signed-off-by: Samuel Just <sjust@redhat.com>
---
 src/crimson/os/seastore/lba_manager.h         | 12 +++++++++++
 .../lba_manager/btree/btree_lba_manager.cc    | 20 +++++++++++++++++++
 .../lba_manager/btree/btree_lba_manager.h     |  5 +++++
 src/crimson/os/seastore/transaction_manager.h | 12 +++++++++++
 4 files changed, 49 insertions(+)

diff --git a/src/crimson/os/seastore/lba_manager.h b/src/crimson/os/seastore/lba_manager.h
index 26646ff0546bd..864637df1980e 100644
--- a/src/crimson/os/seastore/lba_manager.h
+++ b/src/crimson/os/seastore/lba_manager.h
@@ -59,6 +59,18 @@ public:
     Transaction &t,
     laddr_list_t &&extent_lisk) = 0;
 
+  /**
+   * Finds unmapped laddr extent of len len
+   */
+  using find_hole_ertr = base_ertr;
+  using find_hole_ret = find_hole_ertr::future<
+    std::pair<laddr_t, extent_len_t>
+    >;
+  virtual find_hole_ret find_hole(
+    Transaction &t,
+    laddr_t hint,
+    extent_len_t) = 0;
+
   /**
    * Allocates a new mapping referenced by LBARef
    *
diff --git a/src/crimson/os/seastore/lba_manager/btree/btree_lba_manager.cc b/src/crimson/os/seastore/lba_manager/btree/btree_lba_manager.cc
index aa9fea07904dd..bbbf0a90f1c89 100644
--- a/src/crimson/os/seastore/lba_manager/btree/btree_lba_manager.cc
+++ b/src/crimson/os/seastore/lba_manager/btree/btree_lba_manager.cc
@@ -102,6 +102,26 @@ BtreeLBAManager::get_mappings(
     });
 }
 
+BtreeLBAManager::find_hole_ret
+BtreeLBAManager::find_hole(
+  Transaction &t,
+  laddr_t hint,
+  extent_len_t len)
+{
+  return get_root(t
+  ).safe_then([this, hint, len, &t](auto extent) {
+    return extent->find_hole(
+      get_context(t),
+      hint,
+      L_ADDR_MAX,
+      len);
+  }).safe_then([len](auto addr) {
+    return seastar::make_ready_future<std::pair<laddr_t, extent_len_t>>(
+      addr, len);
+  });
+
+}
+
 BtreeLBAManager::alloc_extent_ret
 BtreeLBAManager::alloc_extent(
   Transaction &t,
diff --git a/src/crimson/os/seastore/lba_manager/btree/btree_lba_manager.h b/src/crimson/os/seastore/lba_manager/btree/btree_lba_manager.h
index 76fa2d1944812..34fa328095736 100644
--- a/src/crimson/os/seastore/lba_manager/btree/btree_lba_manager.h
+++ b/src/crimson/os/seastore/lba_manager/btree/btree_lba_manager.h
@@ -58,6 +58,11 @@ public:
     Transaction &t,
     laddr_list_t &&list) final;
 
+  find_hole_ret find_hole(
+    Transaction &t,
+    laddr_t hint,
+    extent_len_t) final;
+
   alloc_extent_ret alloc_extent(
     Transaction &t,
     laddr_t hint,
diff --git a/src/crimson/os/seastore/transaction_manager.h b/src/crimson/os/seastore/transaction_manager.h
index cc62376116265..d8c31a924d6e5 100644
--- a/src/crimson/os/seastore/transaction_manager.h
+++ b/src/crimson/os/seastore/transaction_manager.h
@@ -267,6 +267,18 @@ public:
     });
   }
 
+  using find_hole_ertr = LBAManager::find_hole_ertr;
+  using find_hole_ret = LBAManager::find_hole_ret;
+  find_hole_ret find_hole(
+    Transaction &t,
+    laddr_t hint,
+    extent_len_t len) {
+    return lba_manager->find_hole(
+      t,
+      hint,
+      len);
+  }
+
   /* alloc_extents
    *
    * allocates more than one new blocks of type T.
-- 
2.39.5