[PATCH] ReiserFS: Add I/O error handling to journal operations

[PATCH] ReiserFS: Add I/O error handling to journal operations

This patch allows ReiserFS to handle I/O errors in the journal (or journal
flush) where it would have previously panicked.  The new behavior is to
mark the filesystem read-only, disallow new transactions to be started, and
to allow existing transactions to complete (though not to commit).  The
resultant filesystem can be safely umounted, and checked via normal
mechanisms.  As it is a journaling filesystem, the filesystem itself will
be in a similar state to the power being cut to the machine, once umounted.

Signed-off-by: Jeff Mahoney <jeffm@novell.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>