os/bluestore: implement BlueRocksEnv::AreFilesSame()

it is used by the "repair" feature to dedup the files to be searched for
MANIFEST-* files. the default implementation is the POSIX one, which
tries to look at the local fs, but we should be looking for the files in
the bluefs. in this very use case, wal and db do not share the same device,
so we can just compare the paths. actually, it should aways return
"false". as the files being compared are always "db" and "db.wal".

Fixes: http://tracker.ceph.com/issues/21842
Signed-off-by: Kefu Chai <kchai@redhat.com>

diff --git a/src/os/bluestore/BlueRocksEnv.cc b/src/os/bluestore/BlueRocksEnv.cc
index bf67b982fcdfdd85ca3e5a89291a810466ba58a0..2813b8c23f49b956e25d4decfa6cf1504d36956c 100644 (file)
--- a/src/os/bluestore/BlueRocksEnv.cc
+++ b/src/os/bluestore/BlueRocksEnv.cc
@@ -499,6 +499,29 @@ rocksdb::Status BlueRocksEnv::LinkFile(
   ceph_abort();
 }
 
+rocksdb::Status BlueRocksEnv::AreFilesSame(
+  const std::string& first,
+  const std::string& second, bool* res)
+{
+  for (auto& path : {first, second}) {
+    if (fs->dir_exists(path)) {
+      continue;
+    }
+    std::string dir, file;
+    split(path, &dir, &file);
+    int r = fs->stat(dir, file, nullptr, nullptr);
+    if (!r) {
+      continue;
+    } else if (r == -ENOENT) {
+      return rocksdb::Status::NotFound("AreFilesSame", path);
+    } else {
+      return err_to_status(r);
+    }
+  }
+  *res = (first == second);
+  return rocksdb::Status::OK();
+}
+
 rocksdb::Status BlueRocksEnv::LockFile(
   const std::string& fname,
   rocksdb::FileLock** lock)

diff --git a/src/os/bluestore/BlueRocksEnv.h b/src/os/bluestore/BlueRocksEnv.h
index 555c6964f5c54a4c2a4b296b241122a67220d7bb..909e1b1c174ae1fb185d38ce52a4abafabfc8a59 100644 (file)
--- a/src/os/bluestore/BlueRocksEnv.h
+++ b/src/os/bluestore/BlueRocksEnv.h
@@ -114,6 +114,10 @@ public:
   // Hard Link file src to target.
   rocksdb::Status LinkFile(const std::string& src, const std::string& target) override;
 
+  // Tell if two files are identical
+  rocksdb::Status AreFilesSame(const std::string& first,
+                              const std::string& second, bool* res) override;
+
   // Lock the specified file.  Used to prevent concurrent access to
   // the same db by multiple processes.  On failure, stores nullptr in
   // *lock and returns non-OK.