Btrfs: add mount -o auto_defrag

This will detect small random writes into files and
queue the up for an auto defrag process.  It isn't well suited to
database workloads yet, but works for smaller files such as rpm, sqlite
or bdb databases.

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

1 files changed, 1 insertions, 0 deletions

diff --git a/fs/btrfs/btrfs_inode.h b/fs/btrfs/btrfs_inode.h
index d0b0e43a6a8b..93b1aa932014 100644
--- a/fs/btrfs/btrfs_inode.h
+++ b/fs/btrfs/btrfs_inode.h
@@ -153,6 +153,7 @@ struct btrfs_inode {
         unsigned ordered_data_close:1;
         unsigned orphan_meta_reserved:1;
         unsigned dummy_inode:1;
+        unsigned in_defrag:1;
 
         /*
          * always compress this one file