invariants: don't complain about directories with some NULL lower objects

Directories can have NULL lower objects in between start/end, but NOT if at
the start/end range.  We cannot verify that this dentry is a type=DIR,
because it may already be a negative dentry.  But if dbstart is greater than
dbend, we know that this couldn't have been a regular file: it had to have
been a directory.  In that case, don't complain about NULL lower objects in
in between start/end.

Signed-off-by: Erez Zadok <ezk@cs.sunysb.edu>

diff --git a/fs/unionfs/union.h b/fs/unionfs/union.h
index bb8d2b85f8c95c1f660844d5e0d17fec1bdae783..36a6faa458897b22a5d75910924aec75fb29ddae 100644 (file)
--- a/fs/unionfs/union.h
+++ b/fs/unionfs/union.h
@@ -510,9 +510,19 @@ static inline void unionfs_mntput(struct dentry *dentry, int bindex)
                        return;
                if (!mnt && bindex >= 0) {
 #ifdef UNIONFS_DEBUG
-                       printk(KERN_DEBUG
-                              "unionfs_mntput: mnt=%p bindex=%d\n",
-                              mnt, bindex);
+                       /*
+                        * Directories can have NULL lower objects in
+                        * between start/end, but NOT if at the start/end
+                        * range.  We cannot verify that this dentry is a
+                        * type=DIR, because it may already be a negative
+                        * dentry.  But if dbstart is greater than dbend, we
+                        * know that this couldn't have been a regular file:
+                        * it had to have been a directory.
+                        */
+                       if (!(bindex > dbstart(dentry) && bindex < dbend(dentry)))
+                               printk(KERN_WARNING
+                                      "unionfs_mntput: mnt=%p bindex=%d\n",
+                                      mnt, bindex);
 #endif /* UNIONFS_DEBUG */
                        return;
                }