tools: persist trimmed_pos in journal dump

...rather than inferring something from expire_pos
that could leave trash behind in the range between
the original trimmed_pos and expire_pos.

Be backward compatible with old journal dumps
so that if someone is updating for other reasons
like getting better tools, they can still import
their journal.

Signed-off-by: John Spray <john.spray@redhat.com>

diff --git a/src/tools/cephfs/Dumper.cc b/src/tools/cephfs/Dumper.cc
index 8ee3cdc0b4358a371bbed8b9410c5c2577d0a832..af3e19c57b35b9e1045b4f04702985cbed5cf0de 100644 (file)
--- a/src/tools/cephfs/Dumper.cc
+++ b/src/tools/cephfs/Dumper.cc
@@ -102,12 +102,13 @@ void Dumper::dump(const char *dump_file)
     // include an informative header
     char buf[200];
     memset(buf, 0, sizeof(buf));
-    sprintf(buf, "Ceph mds%d journal dump\n start offset %llu (0x%llx)\n       length %llu (0x%llx)\n    write_pos %llu (0x%llx)\n    format %llu\n%c",
+    sprintf(buf, "Ceph mds%d journal dump\n start offset %llu (0x%llx)\n       length %llu (0x%llx)\n    write_pos %llu (0x%llx)\n    format %llu\n    trimmed_pos %llu (0x%llx)\n%c",
            rank, 
            (unsigned long long)start, (unsigned long long)start,
            (unsigned long long)bl.length(), (unsigned long long)bl.length(),
            (unsigned long long)journaler.last_committed.write_pos, (unsigned long long)journaler.last_committed.write_pos,
            (unsigned long long)journaler.last_committed.stream_format,
+           (unsigned long long)journaler.last_committed.trimmed_pos, (unsigned long long)journaler.last_committed.trimmed_pos,
            4);
     int r = safe_write(fd, buf, sizeof(buf));
     if (r)
@@ -150,16 +151,24 @@ void Dumper::undump(const char *dump_file)
     return;
   }
 
-  long long unsigned start, len, write_pos, format;
+  long long unsigned start, len, write_pos, format, trimmed_pos;
   sscanf(strstr(buf, "start offset"), "start offset %llu", &start);
   sscanf(strstr(buf, "length"), "length %llu", &len);
   sscanf(strstr(buf, "write_pos"), "write_pos %llu", &write_pos);
   sscanf(strstr(buf, "format"), "format %llu", &format);
+  if (strstr(buf, "trimmed_pos")) {
+    sscanf(strstr(buf, "trimmed_pos"), "trimmed_pos %llu", &trimmed_pos);
+  } else {
+    // Old format dump, any untrimmed objects before expire_pos will
+    // be discarded as trash.
+    trimmed_pos = start - (start % g_default_file_layout.fl_object_size);
+  }
+
 
   cout << "start " << start << " len " << len << std::endl;
   
   Journaler::Header h;
-  h.trimmed_pos = start - (start % g_default_file_layout.fl_object_size);
+  h.trimmed_pos = trimmed_pos;
   h.expire_pos = start;
   h.write_pos = write_pos;
   h.stream_format = format;