The attached patch set lp897421-patches.tar.gz has been determined to resolve the problem. This set applies to linux 3.2-rc3 (or Ubuntu-3.2.0-2.5) and has been submitted to upstream lists as "Subject: [PATCH 0/5] fix s_umount thaw/write and journal deadlock".
An ubuntu-precise kernel with this patch set applied is available:
The patch set is comprised of:
Surbhi Palande (2):
Adding support to freeze and unfreeze a journal
Thaw the journal when you unfreeze the fs.
Valerie Aurora (3):
VFS: Fix s_umount thaw/write deadlock
VFS: Rename vfs_check_frozen() to
Documentation: Correct s_umount state for