[PATCH 1/2] btrfs: add necessary comments about tickets_id

[PATCH 1/2] btrfs: add necessary comments about tickets_id

[Wang Xiaoguang]

Tickets_id's name may result in some misunderstandings,  it just indicates
the next ticket will be handled and is not stored per ticket.

Fixes: ce12965 ("btrfs: introduce tickets_id to determine whether
asynchronous metadata reclaim work makes progress")
Signed-off-by: Wang Xiaoguang <wangxg.fnst@cn.fujitsu.com>
---
 fs/btrfs/ctree.h | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 0b8ce2b..9307084 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -429,6 +429,10 @@ struct btrfs_space_info {
 	struct list_head ro_bgs;
 	struct list_head priority_tickets;
 	struct list_head tickets;
+	/*
+	 * tickets_id just indicates the next ticket will be handled, so note
+	 * it's not stored per ticket.
+	 */
 	u64 tickets_id;
 
 	struct rw_semaphore groups_sem;
-- 
2.5.0

[PATCH 2/2] btrfs: increase tickets_id even for failed metadata request

[Wang Xiaoguang]

Not functional change, it just makes codes logic more reasonable, then
at least tickets_id can reflect the number of metadata requests we already
handled.

Signed-off-by: Wang Xiaoguang <wangxg.fnst@cn.fujitsu.com>
---
 fs/btrfs/extent-tree.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 4607af3..d63bf40 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -4949,14 +4949,16 @@ static inline int need_do_async_reclaim(struct btrfs_space_info *space_info,
 			  &root->fs_info->fs_state));
 }
 
-static void wake_all_tickets(struct list_head *head)
+static void wake_all_tickets(struct btrfs_space_info *space_info)
 {
 	struct reserve_ticket *ticket;
+	struct list_head *head = &space_info->tickets;
 
 	while (!list_empty(head)) {
 		ticket = list_first_entry(head, struct reserve_ticket, list);
 		list_del_init(&ticket->list);
 		ticket->error = -ENOSPC;
+		space_info->tickets_id++;
 		wake_up(&ticket->wait);
 	}
 }
@@ -5018,7 +5020,7 @@ static void btrfs_async_reclaim_metadata_space(struct work_struct *work)
 		if (flush_state > COMMIT_TRANS) {
 			commit_cycles++;
 			if (commit_cycles > 2) {
-				wake_all_tickets(&space_info->tickets);
+				wake_all_tickets(space_info);
 				space_info->flush = 0;
 			} else {
 				flush_state = FLUSH_DELAYED_ITEMS_NR;
-- 
2.5.0