btrfs: state information for readahead

Add state information for readahead to btrfs_fs_info and btrfs_device

Changes v2:
 - don't wait in radix_trees
 - add own set of workers for readahead

Reviewed-by: Josef Bacik <josef@redhat.com>
Signed-off-by: Arne Jansen <sensille@gmx.net>

1 files changed, 8 insertions, 0 deletions

diff --git a/fs/btrfs/volumes.h b/fs/btrfs/volumes.h
index 6d866db4e177..2a751246188a 100644
--- a/fs/btrfs/volumes.h
+++ b/fs/btrfs/volumes.h
@@ -92,6 +92,14 @@ struct btrfs_device {
         struct btrfs_work work;
         struct rcu_head rcu;
         struct work_struct rcu_work;
+
+        /* readahead state */
+        spinlock_t reada_lock;
+        atomic_t reada_in_flight;
+        u64 reada_next;
+        struct reada_zone *reada_curr_zone;
+        struct radix_tree_root reada_zones;
+        struct radix_tree_root reada_extents;
 };
 
 struct btrfs_fs_devices {