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Subject[ 17/77] UBIFS: fix use of freed ubifs_orphan objects
Date
3.8-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Adam Thomas <adamthomas1111@gmail.com>

commit 2928f0d0c5ebd6c9605c0d98207a44376387c298 upstream.

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>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
fs/ubifs/orphan.c | 7 ++++++-
fs/ubifs/ubifs.h | 4 +++-
2 files changed, 9 insertions(+), 2 deletions(-)

--- a/fs/ubifs/orphan.c
+++ b/fs/ubifs/orphan.c
@@ -132,7 +132,7 @@ void ubifs_delete_orphan(struct ubifs_in
(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 ubi
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_
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
list_for_each_entry(orphan, &c->orph_list, list) {
if (orphan->new)
continue;
+ orphan->cmt = 1;
*last = orphan;
last = &orphan->cnext;
cnt += 1;
--- 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;
};

/**



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