This patch fixes two related issues:
- If a large (>PIPE_BUF) pipe write is processed partially, only to be
followed by a write error condition, then the process is left in an
incorrect state, possibly causing VFS to crash on a subsequent call.
- If such a partially processed large pipe write ends up resulting in
an EPIPE error, no corresponding SIGPIPE signal is generated.
The corrected behavior is tested in test68.
Change-Id: I5540e61ab6bcc60a31201485eda04bc49ece2ca8
179bddcf5d