From: Xuehan Xu <xuxuehan@qianxin.com>
Date: Thu, 27 Feb 2025 05:54:49 +0000 (+0800)
Subject: crimson/os/seastore/cache: do `prepare_commit` before retiring extents
X-Git-Tag: v20.3.0~79^2~6
X-Git-Url: http://git.apps.os.sepia.ceph.com/?a=commitdiff_plain;h=20b0d5a9c30bb9c099899d456eafb823234dbd82;p=ceph.git

crimson/os/seastore/cache: do `prepare_commit` before retiring extents

Linked tree nodes in logical trees need to take parents from the prior
instances when being rewritten, which has to be done before the prior
instances are retired.

Signed-off-by: Xuehan Xu <xuxuehan@qianxin.com>
---

diff --git a/src/crimson/os/seastore/cache.cc b/src/crimson/os/seastore/cache.cc
index d94193f8176d9..53b23025cd665 100644
--- a/src/crimson/os/seastore/cache.cc
+++ b/src/crimson/os/seastore/cache.cc
@@ -1340,6 +1340,14 @@ record_t Cache::prepare_record(
     delta_stat.increment(delta_length);
   }
 
+  t.for_each_finalized_fresh_block([](auto &e) {
+    // fresh blocks' `prepare_commit` must be invoked before
+    // retiering extents, this is because logical linked tree
+    // nodes needs to access their prior instances in this
+    // phase if they are rewritten.
+    e->prepare_commit();
+  });
+
   // Transaction is now a go, set up in-memory cache state
   // invalidate now invalid blocks
   io_stat_t retire_stat;
@@ -1403,7 +1411,6 @@ record_t Cache::prepare_record(
 
     bufferlist bl;
     i->prepare_write();
-    i->prepare_commit();
     bl.append(i->get_bptr());
     if (is_root_type(i->get_type())) {
       ceph_assert(0 == "ROOT never gets written as a fresh block");
@@ -1457,7 +1464,6 @@ record_t Cache::prepare_record(
     assert(!i->is_inline());
     get_by_ext(efforts.fresh_ool_by_ext,
                i->get_type()).increment(i->get_length());
-    i->prepare_commit();
     if (is_backref_mapped_type(i->get_type())) {
       laddr_t alloc_laddr;
       if (i->is_logical()) {