Btrfs: O_DIRECT writes via buffered writes + invaldiate

This reworks the btrfs O_DIRECT write code a bit.  It had always fallen
back to buffered IO and done an invalidate, but needed to be updated
for the data=ordered code.  The invalidate wasn't actually removing pages
because they were still inside an ordered extent.

This also combines the O_DIRECT/O_SYNC paths where possible, and kicks
off IO in the main btrfs_file_write loop to keep the pipe down the the
disk full as we process long writes.

Signed-off-by: Chris Mason <chris.mason@oracle.com>

1 files changed, 2 insertions, 1 deletions

diff --git a/fs/btrfs/ordered-data.c b/fs/btrfs/ordered-data.c
index dcc1730dd837..2eb6caba57c2 100644
--- a/fs/btrfs/ordered-data.c
+++ b/fs/btrfs/ordered-data.c
@@ -397,7 +397,7 @@ void btrfs_start_ordered_extent(struct inode *inode,
 /*
  * Used to wait on ordered extents across a large range of bytes.
  */
-void btrfs_wait_ordered_range(struct inode *inode, u64 start, u64 len)
+int btrfs_wait_ordered_range(struct inode *inode, u64 start, u64 len)
 {
         u64 end;
         u64 orig_end;
@@ -451,6 +451,7 @@ again:
                        (unsigned long long)orig_end);
                 goto again;
         }
+        return 0;
 }
 
 /*