do_logfs_journal_wl_pass() must call freeseg(), thereby clear
PagePrivate on all pages of the current journal segment.
Signed-off-by: Joern Engel <joern@logfs.org>
A comment in the old code read:
/* The math in this function can surely use some love */
And indeed it did. In the case that area->a_used_bytes is exactly
4096 bytes below segment size it fell apart. pad_wbuf is now split
into two helpers that are significantly less complicated.
Signed-off-by: Joern Engel <joern@logfs.org>
Erases for block devices were always just emulated by writing 0xff.
Some time back the write was removed and only the page cache was
changed to 0xff. Superficialy a good idea with two problems:
1. Touching the page cache isn't necessary either.
2. However, writing out 0xff _is_ necessary for the journal. As the
journal is scanned linearly, an old non-overwritten commit entry
can be used on next mount and cause havoc.
This should fix both aspects.
