Truncate would do an almost limitless amount of work without invoking
the garbage collector in between.  Split it up into more manageable,
though still large, chunks.
Signed-off-by: NJoern Engel <joern@logfs.org>

It would probably be better to just accept NULL pointers in
mempool_destroy().  But for the current -rc series let's keep things
simple.

This patch was lost in the cracks for a while.
Kevin Cernekee <cernekee@gmail.com> had to rediscover the problem and
send a similar patch because of it. :(
Signed-off-by: NJoern Engel <joern@logfs.org>

Removing sufficiently large files would create aliases for a large
number of segments.  This in turn results in a large number of journal
entries and an overflow of s_je_array.

Cheap fix is to add a BUG_ON, turning memory corruption into something
annoying, but less dangerous.  Real fix is to count the number of
affected segments and prevent the problem completely.
Signed-off-by: NJoern Engel <joern@logfs.org>

All callers are long gone.
Signed-off-by: NJoern Engel <joern@logfs.org>

The comment was correct, so make the code match the comment.  As the
new comment indicates, we might be able to do a little less work.  But
for the current -rc series let's keep it simple and just fix the bug.
Signed-off-by: NJoern Engel <joern@logfs.org>

This prevents unnecessary journal writes.  More importantly it prevents
an oops due to a journal write on failed mount.

This is a new flash file system. See
Documentation/filesystems/logfs.txt
Signed-off-by: NJoern Engel <joern@logfs.org>