cifs: fix cifsFileInfo leak on kmalloc failure in deferred close drain paths

In cifs_close_deferred_file(), cifs_close_all_deferred_files(), and
cifs_close_deferred_file_under_dentry(), when a pending deferred close
is cancelled via cancel_delayed_work(), the subsequent kmalloc_obj() to
add the file to the local processing list may fail under memory pressure.
The loop breaks immediately, but the cancelled work is no longer pending
(it would have called _cifsFileInfo_put()), and the cfile is never added
to file_head for processing.  The cifsFileInfo reference and the open
server handle both leak.

Fix by saving the cfile that failed allocation in a local variable,
breaking as before, and calling _cifsFileInfo_put() on it after
releasing the lock.  Any files later in the iteration are unaffected
since their deferred work is still pending and will fire normally.

Fixes: e3fc065682eb ("cifs: Deferred close performance improvements")
Signed-off-by: Frank Sorenson <sorenson@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>

0 files changed, 0 insertions, 0 deletions