Hello,

I'm testing UFS with SU+J. But it seems sometimes broken journal data has 
written.

In softdep_process_journal (ffs_softdep.c), there is a while code to build 
jsegrec and each entry.
But by my test, sometimes there is no entry then break this while code without 
building jsegrec.
If this happens, bp->b_data is not initialized but this bp is written, I think.

I checked this behavior by following patch.
============================================================================================
diff --git a/sys/ufs/ffs/ffs_softdep.c b/sys/ufs/ffs/ffs_softdep.c
index 585af50..2d4939c 100644
--- a/sys/ufs/ffs/ffs_softdep.c
+++ b/sys/ufs/ffs/ffs_softdep.c
@@ -3421,6 +3421,15 @@ softdep_process_journal(mp, needwk, flags)
                        data = bp->b_data + off;
                        cnt--;
                }
+
+#if 1
+               if (off == 0) {
+                       struct jsegrec *tmp = (struct jsegrec*)bp->b_data;
+                       if (tmp->jsr_seq != jseg->js_seq) {
+                               panic("test test");
+                       }
+               }
+#endif
                /*
                 * Write this one buffer and continue.
                 */
============================================================================================

If uninitialized data is "valid" by fsck suj, this may result filesystem 
corruption, I think.
I think it's better to clear b_data before using it.

_______________________________________________
freebsd-current@freebsd.org mailing list
http://lists.freebsd.org/mailman/listinfo/freebsd-current
To unsubscribe, send any mail to "freebsd-current-unsubscr...@freebsd.org"

Reply via email to