Commit d3aaeea7 authored by Filipe Manana's avatar Filipe Manana Committed by David Sterba
Browse files

btrfs: add comments regarding locking to struct btrfs_delayed_ref_root 



Add some comments to struct btrfs_delayed_ref_root's fields to mention
what its spinlock protects.

Reviewed-by: default avatarBoris Burkov <boris@bur.io>
Reviewed-by: default avatarQu Wenruo <wqu@suse.com>
Signed-off-by: default avatarFilipe Manana <fdmanana@suse.com>
Reviewed-by: default avatarDavid Sterba <dsterba@suse.com>
Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
parent a8985ac6

fs/btrfs/delayed-ref.h

+17 −3
Original line number Diff line number Diff line
@@ -213,19 +213,33 @@ struct btrfs_delayed_ref_root { 
	 */

	struct xarray dirty_extents;



	/* this spin lock protects the rbtree and the entries inside */

	/*

	 * Protects the rbtree href_root, its entries and the following fields:

	 * num_heads, num_heads_ready, pending_csums and run_delayed_start.

	 */

	spinlock_t lock;



	/* total number of head nodes in tree */

	/* Total number of head refs, protected by the spinlock 'lock'. */

	unsigned long num_heads;



	/* total number of head nodes ready for processing */

	/*

	 * Total number of head refs ready for processing, protected by the

	 * spinlock 'lock'.

	 */

	unsigned long num_heads_ready;



	/*

	 * Track space reserved for deleting csums of data extents.

	 * Protected by the spinlock 'lock'.

	 */

	u64 pending_csums;



	unsigned long flags;



	/*

	 * Track from which bytenr to start searching ref heads.

	 * Protected by the spinlock 'lock'.

	 */

	u64 run_delayed_start;



	/*