Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/btrfs...

* 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/btrfs-unstable:
  Btrfs: always pin metadata in discard mode
  Btrfs: enable discard support
  Btrfs: add -o discard option
  Btrfs: properly wait log writers during log sync
  Btrfs: fix possible ENOSPC problems with truncate
  Btrfs: fix btrfs acl #ifdef checks
  Btrfs: streamline tree-log btree block writeout
  Btrfs: avoid tree log commit when there are no changes
  Btrfs: only write one super copy during fsync

diff --cc fs/btrfs/ctree.h
Simple merge

diff --cc fs/btrfs/disk-io.c
Simple merge

diff --cc fs/btrfs/extent-tree.c
index d0c4d584efadd9cf92050bf0da946e364da2dc8a,c56f91639dc13562dbe107dcd5d2d0f0e72683eb..e238a0cdac677c06b1774018bf549b03399da4c8
--- 1/fs/btrfs/extent-tree.c
--- 2/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@@ -1571,11 -1571,8 +1571,9 @@@ static int remove_extent_backref(struc
  static void btrfs_issue_discard(struct block_device *bdev,
                                u64 start, u64 len)
  {
 -      blkdev_issue_discard(bdev, start >> 9, len >> 9, GFP_KERNEL);
 +      blkdev_issue_discard(bdev, start >> 9, len >> 9, GFP_KERNEL,
 +                           DISCARD_FL_BARRIER);
  }
- #endif
  
  static int btrfs_discard_extent(struct btrfs_root *root, u64 bytenr,
                                u64 num_bytes)

diff --cc fs/btrfs/file.c
Simple merge

diff --cc fs/btrfs/inode.c
Simple merge

diff --cc fs/btrfs/super.c
Simple merge

diff --cc fs/btrfs/tree-log.c
Simple merge