If the journal has aborted due to a checkpointing failure, we have to
keep the contents of the journal space.  Otherwise, the filesystem will
lose uncheckpointed metadata completely and become inconsistent.  To
avoid this, we need to keep needs_recovery flag if checkpoint has
failed.

With this patch, ext3_put_super() detects a checkpointing failure from
the return value of journal_destroy(), then it invokes ext3_abort() to
make the filesystem read only and keep needs_recovery flag.  Errors
from journal_flush() are also handled by this patch in some places.
Signed-off-by: Hidehiro Kawai <hidehiro.kawai.ez@hitachi.com>
Cc: Jan Kara <jack@ucw.cz>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: <linux-ext4@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>