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.c b/fs/btrfs/volumes.c
index f2a4cc79da6..1dccce5bc93 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -366,6 +366,14 @@ static noinline int device_list_add(const char *path,
                 }
                 INIT_LIST_HEAD(&device->dev_alloc_list);
 
+                /* init readahead state */
+                spin_lock_init(&device->reada_lock);
+                device->reada_curr_zone = NULL;
+                atomic_set(&device->reada_in_flight, 0);
+                device->reada_next = 0;
+                INIT_RADIX_TREE(&device->reada_zones, GFP_NOFS & ~__GFP_WAIT);
+                INIT_RADIX_TREE(&device->reada_extents, GFP_NOFS & ~__GFP_WAIT);
+
                 mutex_lock(&fs_devices->device_list_mutex);
                 list_add_rcu(&device->dev_list, &fs_devices->devices);
                 mutex_unlock(&fs_devices->device_list_mutex);