reiserfs: fix corruption introduced by balance_leaf refactor

Commits f1f007c308e (reiserfs: balance_leaf refactor, pull out
balance_leaf_insert_left) and cf22df182bf (reiserfs: balance_leaf
refactor, pull out balance_leaf_paste_left) missed that the `body'
pointer was getting repositioned. Subsequent users of the pointer
would expect it to be repositioned, and as a result, parts of the
tree would get overwritten. The most common observed corruption
is indirect block pointers being overwritten.

Since the body value isn't actually used anymore in the called routines,
we can pass back the offset it should be shifted. We constify the body
and ih pointers in the balance_leaf as a mostly-free preventative measure.

Cc: <stable@vger.kernel.org> # 3.16
Reported-and-tested-by: Jeff Chua <jeff.chua.linux@gmail.com>
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: Jan Kara <jack@suse.cz>
reiserfs: Fix use after free in journal teardown

If do_journal_release() races with do_journal_end() which requeues
delayed works for transaction flushing, we can leave work items for
flushing outstanding transactions queued while freeing them. That
results in use after free and possible crash in run_timers_softirq().

Fix the problem by not requeueing works if superblock is being shut down
(MS_ACTIVE not set) and using cancel_delayed_work_sync() in
do_journal_release().

CC: stable@vger.kernel.org
Signed-off-by: Jan Kara <jack@suse.cz>
Merge branch 'linux-3.16.0-reiserfs' into linux-3.16.2-plus-v2_01_