UBIFS: fix use of freed ubifs_orphan objects

The last orphan in the cnext list has its cnext set to NULL. Because
of that, ubifs_delete_orphan assumes that it is not on the cnext list
and frees it immediately instead of adding it to the dnext list. The
freed orphan is later modified by write_orph_node.

This can cause various inconsistencies including directory entries
that cannot be removed and this error:

UBIFS error (pid 20685): layout_cnodes: LPT out of space at LEB 14:129009 needing 17, done_ltab 1, done_lsave 1

This is a regression introduced by
"7074e5eb UBIFS: remove invalid reference to list iterator variable".

This change adds an explicit flag to ubifs_orphan indicating whether
it is pending commit.

Signed-off-by: Adam Thomas <adamthomas1111@gmail.com>
Reviewed-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: stable@vger.kernel.org # v3.6+
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>

1 files changed, 3 insertions, 1 deletions

diff --git a/fs/ubifs/ubifs.h b/fs/ubifs/ubifs.h
index d133c276fe05..c16fff7271d3 100644
--- a/fs/ubifs/ubifs.h
+++ b/fs/ubifs/ubifs.h
@@ -904,6 +904,7 @@ struct ubifs_budget_req {
  * @dnext: next orphan to delete
  * @inum: inode number
  * @new: %1 => added since the last commit, otherwise %0
+ * @cmt: %1 => commit pending, otherwise %0
  */
 struct ubifs_orphan {
         struct rb_node rb;
@@ -912,7 +913,8 @@ struct ubifs_orphan {
         struct ubifs_orphan *cnext;
         struct ubifs_orphan *dnext;
         ino_t inum;
-        int new;
+        unsigned new:1;
+        unsigned cmt:1;
 };
 
 /**