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>

diff --git a/fs/ubifs/orphan.c b/fs/ubifs/orphan.c
index 769701ccb5c9bf5809a3f09b17ade8397a4dbfb2..8534d9c6492f064d4579b3854fa1352cb0dd8eb0 100644 (file)
--- a/fs/ubifs/orphan.c
+++ b/fs/ubifs/orphan.c
@@ -132,7 +132,7 @@ void ubifs_delete_orphan(struct ubifs_info *c, ino_t inum)
                                        (unsigned long)inum);
                                return;
                        }
-                       if (o->cnext) {
+                       if (o->cmt) {
                                o->dnext = c->orph_dnext;
                                c->orph_dnext = o;
                                spin_unlock(&c->orphan_lock);
@@ -172,7 +172,9 @@ int ubifs_orphan_start_commit(struct ubifs_info *c)
        last = &c->orph_cnext;
        list_for_each_entry(orphan, &c->orph_new, new_list) {
                ubifs_assert(orphan->new);
+               ubifs_assert(!orphan->cmt);
                orphan->new = 0;
+               orphan->cmt = 1;
                *last = orphan;
                last = &orphan->cnext;
        }
@@ -299,7 +301,9 @@ static int write_orph_node(struct ubifs_info *c, int atomic)
        cnext = c->orph_cnext;
        for (i = 0; i < cnt; i++) {
                orphan = cnext;
+               ubifs_assert(orphan->cmt);
                orph->inos[i] = cpu_to_le64(orphan->inum);
+               orphan->cmt = 0;
                cnext = orphan->cnext;
                orphan->cnext = NULL;
        }
@@ -378,6 +382,7 @@ static int consolidate(struct ubifs_info *c)
                list_for_each_entry(orphan, &c->orph_list, list) {
                        if (orphan->new)
                                continue;
+                       orphan->cmt = 1;
                        *last = orphan;
                        last = &orphan->cnext;
                        cnt += 1;

diff --git a/fs/ubifs/ubifs.h b/fs/ubifs/ubifs.h
index d133c276fe05d526c647756c704ef37a8438612e..c16fff7271d3788376b5aef7215920eba32c58ff 100644 (file)
--- 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;
 };
 
 /**