crimson/os/seastore/async_cleaner: make backref retrieval trans non-weak

backref retrieval transactions may conflict with others on RootBlock

Signed-off-by: Xuehan Xu <xxhdx1985126@gmail.com>

diff --git a/src/crimson/os/seastore/async_cleaner.cc b/src/crimson/os/seastore/async_cleaner.cc
index 1564698526b4d033e558589caa539509bc3cd8b8..7d73adcbe20ada9ae5dae324ca26bf5c054ecebb 100644 (file)
--- a/src/crimson/os/seastore/async_cleaner.cc
+++ b/src/crimson/os/seastore/async_cleaner.cc
@@ -1160,31 +1160,41 @@ SegmentCleaner::clean_space_ret SegmentCleaner::clean_space()
   // Backref-tree doesn't support tree-read during tree-updates with parallel
   // transactions.  So, concurrent transactions between trim and reclaim are
   // not allowed right now.
-  return extent_callback->with_transaction_weak(
-      "retrieve_from_backref_tree",
-      [this](auto &t) {
-    return backref_manager.get_mappings(
-      t,
-      reclaim_state->start_pos,
-      reclaim_state->end_pos
-    ).si_then([this, &t](auto pin_list) {
-      if (!pin_list.empty()) {
-       auto it = pin_list.begin();
-       auto &first_pin = *it;
-       if (first_pin->get_key() < reclaim_state->start_pos) {
-         // BackrefManager::get_mappings may include a entry before
-         // reclaim_state->start_pos, which is semantically inconsistent
-         // with the requirements of the cleaner
-         pin_list.erase(it);
-       }
-      }
-      return backref_manager.retrieve_backref_extents_in_range(
-        t,
-        reclaim_state->start_pos,
-        reclaim_state->end_pos
-      ).si_then([pin_list=std::move(pin_list)](auto extents) mutable {
-        return std::make_pair(std::move(extents), std::move(pin_list));
+  return seastar::do_with(
+    std::pair<std::vector<CachedExtentRef>, backref_pin_list_t>(),
+    [this](auto &weak_read_ret) {
+    return repeat_eagain([this, &weak_read_ret] {
+      return extent_callback->with_transaction_intr(
+         Transaction::src_t::READ,
+         "retrieve_from_backref_tree",
+         [this, &weak_read_ret](auto &t) {
+       return backref_manager.get_mappings(
+         t,
+         reclaim_state->start_pos,
+         reclaim_state->end_pos
+       ).si_then([this, &t, &weak_read_ret](auto pin_list) {
+         if (!pin_list.empty()) {
+           auto it = pin_list.begin();
+           auto &first_pin = *it;
+           if (first_pin->get_key() < reclaim_state->start_pos) {
+             // BackrefManager::get_mappings may include a entry before
+             // reclaim_state->start_pos, which is semantically inconsistent
+             // with the requirements of the cleaner
+             pin_list.erase(it);
+           }
+         }
+         return backref_manager.retrieve_backref_extents_in_range(
+           t,
+           reclaim_state->start_pos,
+           reclaim_state->end_pos
+         ).si_then([pin_list=std::move(pin_list),
+                   &weak_read_ret](auto extents) mutable {
+           weak_read_ret = std::make_pair(std::move(extents), std::move(pin_list));
+         });
+       });
       });
+    }).safe_then([&weak_read_ret] {
+      return std::move(weak_read_ret);
     });
   }).safe_then([this, FNAME, pavail_ratio, start](auto weak_read_ret) {
     return seastar::do_with(