[PATCH] Allow file systems to differentiate between data and meta reads

We can use this information for making more intelligent priority
decisions, and it will also be useful for blktrace.

Signed-off-by: Jens Axboe <axboe@suse.de>

diff --cc block/ll_rw_blk.c
Simple merge

diff --cc include/linux/bio.h
Simple merge

diff --cc include/linux/blkdev.h
Simple merge

diff --cc include/linux/fs.h
Simple merge