Btrfs: don't use highmem for free space cache pages
authorChris Mason <clm@fb.com>
Mon, 6 Apr 2015 14:48:20 +0000 (07:48 -0700)
committerChris Mason <clm@fb.com>
Fri, 10 Apr 2015 21:07:18 +0000 (14:07 -0700)
commit2b108268006e06d57ec9810f4ccf5d99d7e5b598
tree349dd004791477ef08e430d32fcb91be3ed6ebff
parentc9dc4c6578502c2085705347375b82089aad18d0
Btrfs: don't use highmem for free space cache pages

In order to create the free space cache concurrently with FS modifications,
we need to take a few block group locks.

The cache code also does kmap, which would schedule with the locks held.
Instead of going through kmap_atomic, lets just use lowmem for the cache
pages.

Signed-off-by: Chris Mason <clm@fb.com>
fs/btrfs/free-space-cache.c