Commit df903e5d authored by Pavel Begunkov's avatar Pavel Begunkov Committed by David Sterba
Browse files

btrfs: don't miss async discards after scheduled work override 



If btrfs_discard_schedule_work() is called with override=true, it sets
delay anew regardless how much time is left until the timer should have
fired. If delays are long (that can happen, for example, with low
kbps_limit), they might get constantly overridden without having a
chance to run the discard work.

Reviewed-by: default avatarJosef Bacik <josef@toxicpanda.com>
Signed-off-by: default avatarPavel Begunkov <asml.silence@gmail.com>
Reviewed-by: default avatarDavid Sterba <dsterba@suse.com>
Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
parent 6e88f116

fs/btrfs/ctree.h

+1 −0
Original line number Diff line number Diff line
@@ -469,6 +469,7 @@ struct btrfs_discard_ctl { 
	struct btrfs_block_group *block_group;

	struct list_head discard_list[BTRFS_NR_DISCARD_LISTS];

	u64 prev_discard;

	u64 prev_discard_time;

	atomic_t discardable_extents;

	atomic64_t discardable_bytes;

	u64 max_discard_size;

fs/btrfs/discard.c

+15 −0
Original line number Diff line number Diff line
@@ -381,6 +381,15 @@ void btrfs_discard_schedule_work(struct btrfs_discard_ctl *discard_ctl, 
			delay = max(delay, bg_timeout);

		}



		if (override && discard_ctl->prev_discard) {

			u64 elapsed = now - discard_ctl->prev_discard_time;



			if (delay > elapsed)

				delay -= elapsed;

			else

				delay = 0;

		}



		mod_delayed_work(discard_ctl->discard_workers,

				 &discard_ctl->work, nsecs_to_jiffies(delay));

	}
@@ -465,7 +474,12 @@ static void btrfs_discard_workfn(struct work_struct *work) 
		discard_ctl->discard_extent_bytes += trimmed;

	}



	/*

	 * Updated without locks as this is inside the workfn and nothing else

	 * is reading the values

	 */

	discard_ctl->prev_discard = trimmed;

	discard_ctl->prev_discard_time = ktime_get_ns();



	/* Determine next steps for a block_group */

	if (block_group->discard_cursor >= btrfs_block_group_end(block_group)) {
@@ -685,6 +699,7 @@ void btrfs_discard_init(struct btrfs_fs_info *fs_info) 
		INIT_LIST_HEAD(&discard_ctl->discard_list[i]);



	discard_ctl->prev_discard = 0;

	discard_ctl->prev_discard_time = 0;

	atomic_set(&discard_ctl->discardable_extents, 0);

	atomic64_set(&discard_ctl->discardable_bytes, 0);

	discard_ctl->max_discard_size = BTRFS_ASYNC_DISCARD_DEFAULT_MAX_SIZE;