Commit 4d945011 authored by Filipe Manana's avatar Filipe Manana Committed by David Sterba
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btrfs: document what the spinlock unused_bgs_lock protects 



Add some comments to struct btrfs_fs_info to explicitly document which
members are protected by the spinlock unused_bgs_lock. It is currently
used to protect two linked lists, the reclaim_bgs and unused_bgs lists.

So add an explicit comment on top of each list to mention its protected
by unused_bgs_lock, as well as comment on top of unused_bgs_lock to
mention the lists it protects.

Reviewed-by: default avatarJohannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: default avatarJosef Bacik <josef@toxicpanda.com>
Reviewed-by: default avatarBoris Burkov <boris@bur.io>
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 91701bdf

fs/btrfs/fs.h

+3 −0
Original line number Diff line number Diff line
@@ -731,10 +731,13 @@ struct btrfs_fs_info { 


	/* Reclaim partially filled block groups in the background */

	struct work_struct reclaim_bgs_work;

	/* Protected by unused_bgs_lock. */

	struct list_head reclaim_bgs;

	int bg_reclaim_threshold;



	/* Protects the lists unused_bgs and reclaim_bgs. */

	spinlock_t unused_bgs_lock;

	/* Protected by unused_bgs_lock. */

	struct list_head unused_bgs;

	struct mutex unused_bg_unpin_mutex;

	/* Protect block groups that are going to be deleted */