From: Josef Bacik <josef@toxicpanda.com>
Date: Thu, 22 Aug 2019 15:10:58 -0400
Subject: btrfs: refactor the ticket wakeup code
Git-commit: 18fa2284aac3f1071f51a897dc5585178cae458f
Patch-mainline: v5.4-rc1
References: bsc#1165949

Now that btrfs_space_info_add_old_bytes simply checks if we can make the
reservation and updates bytes_may_use, there's no reason to have both
helpers in place.

Factor out the ticket wakeup logic into it's own helper, make
btrfs_space_info_add_old_bytes() update bytes_may_use and then call the
wakeup helper, and replace all calls to btrfs_space_info_add_new_bytes()
with the wakeup helper.

Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Acked-by: Nikolay Borisov <nborisov@suse.com>
---
 fs/btrfs/extent-tree.c |    4 +--
 fs/btrfs/space-info.c  |   52 ++++---------------------------------------------
 fs/btrfs/space-info.h  |   19 ++++++++++++-----
 3 files changed, 20 insertions(+), 55 deletions(-)

--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -3076,8 +3076,8 @@ static int unpin_extent_range(struct btr
 			spin_unlock(&global_rsv->lock);
 			/* Add to any tickets we may have */
 			if (len)
-				btrfs_space_info_add_new_bytes(fs_info,
-						space_info, len);
+				btrfs_try_granting_tickets(fs_info,
+							   space_info);
 		}
 		spin_unlock(&space_info->lock);
 	}
--- a/fs/btrfs/space-info.c
+++ b/fs/btrfs/space-info.c
@@ -153,9 +153,7 @@ void btrfs_update_space_info(struct btrf
 	found->bytes_readonly += bytes_readonly;
 	if (total_bytes > 0)
 		found->full = 0;
-	btrfs_space_info_add_new_bytes(info, found,
-				       total_bytes - bytes_used -
-				       bytes_readonly);
+	btrfs_try_granting_tickets(info, found);
 	spin_unlock(&found->lock);
 	*space_info = found;
 }
@@ -253,17 +251,15 @@ static int can_overcommit(struct btrfs_r
  * This is for space we already have accounted in space_info->bytes_may_use, so
  * basically when we're returning space from block_rsv's.
  */
-void btrfs_space_info_add_old_bytes(struct btrfs_fs_info *fs_info,
-				    struct btrfs_space_info *space_info,
-				    u64 num_bytes)
+void btrfs_try_granting_tickets(struct btrfs_fs_info *fs_info,
+				struct btrfs_space_info *space_info)
 {
 	struct list_head *head;
 	enum btrfs_reserve_flush_enum flush = BTRFS_RESERVE_NO_FLUSH;
 
-	spin_lock(&space_info->lock);
-	head = &space_info->priority_tickets;
-	btrfs_space_info_update_bytes_may_use(fs_info, space_info, -num_bytes);
+	lockdep_assert_held(&space_info->lock);
 
+	head = &space_info->priority_tickets;
 again:
 	while (!list_empty(head)) {
 		struct reserve_ticket *ticket;
@@ -293,44 +289,6 @@ again:
 		flush = BTRFS_RESERVE_FLUSH_ALL;
 		goto again;
 	}
-	spin_unlock(&space_info->lock);
-}
-/*
- * This is for newly allocated space that isn't accounted in
- * space_info->bytes_may_use yet.  So if we allocate a chunk or unpin an extent
- * we use this helper.
- */
-void btrfs_space_info_add_new_bytes(struct btrfs_fs_info *fs_info,
-				    struct btrfs_space_info *space_info,
-				    u64 num_bytes)
-{
-	struct reserve_ticket *ticket;
-	struct list_head *head = &space_info->priority_tickets;
-
-again:
-	while (!list_empty(head) && num_bytes) {
-		ticket = list_first_entry(head, struct reserve_ticket,
-					  list);
-		if (num_bytes >= ticket->bytes) {
-			list_del_init(&ticket->list);
-			num_bytes -= ticket->bytes;
-			btrfs_space_info_update_bytes_may_use(fs_info,
-					space_info, ticket->bytes);
-			ticket->bytes = 0;
-			space_info->tickets_id++;
-			wake_up(&ticket->wait);
-		} else {
-			btrfs_space_info_update_bytes_may_use(fs_info,
-					space_info, num_bytes);
-			ticket->bytes -= num_bytes;
-			num_bytes = 0;
-		}
-	}
-
-	if (num_bytes && head == &space_info->priority_tickets) {
-		head = &space_info->tickets;
-		goto again;
-	}
 }
 
 #define DUMP_BLOCK_RSV(fs_info, rsv_name)				\
--- a/fs/btrfs/space-info.h
+++ b/fs/btrfs/space-info.h
@@ -110,12 +110,6 @@ btrfs_space_info_update_##name(struct bt
 DECLARE_SPACE_INFO_UPDATE(bytes_may_use, "space_info");
 DECLARE_SPACE_INFO_UPDATE(bytes_pinned, "pinned");
 
-void btrfs_space_info_add_new_bytes(struct btrfs_fs_info *fs_info,
-				    struct btrfs_space_info *space_info,
-				    u64 num_bytes);
-void btrfs_space_info_add_old_bytes(struct btrfs_fs_info *fs_info,
-				    struct btrfs_space_info *space_info,
-				    u64 num_bytes);
 int btrfs_init_space_info(struct btrfs_fs_info *fs_info);
 void btrfs_update_space_info(struct btrfs_fs_info *info, u64 flags,
 			     u64 total_bytes, u64 bytes_used,
@@ -133,5 +127,18 @@ int btrfs_reserve_metadata_bytes(struct
 				 struct btrfs_block_rsv *block_rsv,
 				 u64 orig_bytes,
 				 enum btrfs_reserve_flush_enum flush);
+void btrfs_try_granting_tickets(struct btrfs_fs_info *fs_info,
+				struct btrfs_space_info *space_info);
+
+static inline void btrfs_space_info_add_old_bytes(
+				struct btrfs_fs_info *fs_info,
+				struct btrfs_space_info *space_info,
+				u64 num_bytes)
+{
+	spin_lock(&space_info->lock);
+	btrfs_space_info_update_bytes_may_use(fs_info, space_info, -num_bytes);
+	btrfs_try_granting_tickets(fs_info, space_info);
+	spin_unlock(&space_info->lock);
+}
 
 #endif /* BTRFS_SPACE_INFO_H */