- Avoid calling bread() with different sizes on the same blkno.
Although the buffer cache is designed to handle differing size
buffers, it erroneously tries to write the incorrectly-sized buffer
buffer back to disk before reading the correctly-sized one, even
when it's not dirty. This behaviour caused a panic for read-only
NTFS mounts when INVARIANTS was enabled ("bundirty: buffer x still
on queue y"), reported by NAKAJI Hiroyuki.
- Fix a bug in the code handling holes: a variable was incremented
instead of decremented, which could cause an infinite loop.
a222314fe6