commit 18f2c4fc upstream.

If the file system has been shut down or is read-only, then
ext4_write_inode() needs to bail out early.

Also use jbd2_complete_transaction() instead of ext4_force_commit() so
we only force a commit if it is needed.
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>