Btrfs: remove no longer used stuff for tracking pending ordered extents

Tracking pending ordered extents per transaction was introduced in commit
50d9aa99 ("Btrfs: make sure logged extents complete in the current
transaction V3") and later updated in commit 161c3549 ("Btrfs: change
how we wait for pending ordered extents").

However now that on fsync we always wait for ordered extents to complete
before logging, done in commit 5636cf7d ("btrfs: remove the logged
extents infrastructure"), we no longer need the stuff to track for pending
ordered extents, which was not completely removed in the mentioned commit.
So remove the remaining of the pending ordered extents infrastructure.
Reviewed-by: Liu Bo <bo.liu@linux.alibaba.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

fs/btrfs/ordered-data.c

@@ -460,7 +460,6 @@ void btrfs_remove_ordered_extent(struct inode *inode,
 	struct btrfs_inode *btrfs_inode = BTRFS_I(inode);
 	struct btrfs_root *root = btrfs_inode->root;
 	struct rb_node *node;
-	bool dec_pending_ordered = false;
 
 	/* This is paired with btrfs_add_ordered_extent. */
 	spin_lock(&btrfs_inode->lock);
@@ -477,37 +476,8 @@ void btrfs_remove_ordered_extent(struct inode *inode,
 	if (tree->last == node)
 		tree->last = NULL;
 	set_bit(BTRFS_ORDERED_COMPLETE, &entry->flags);
-	if (test_and_clear_bit(BTRFS_ORDERED_PENDING, &entry->flags))
-		dec_pending_ordered = true;
 	spin_unlock_irq(&tree->lock);
 
-	/*
-	 * The current running transaction is waiting on us, we need to let it
-	 * know that we're complete and wake it up.
-	 */
-	if (dec_pending_ordered) {
-		struct btrfs_transaction *trans;
-
-		/*
-		 * The checks for trans are just a formality, it should be set,
-		 * but if it isn't we don't want to deref/assert under the spin
-		 * lock, so be nice and check if trans is set, but ASSERT() so
-		 * if it isn't set a developer will notice.
-		 */
-		spin_lock(&fs_info->trans_lock);
-		trans = fs_info->running_transaction;
-		if (trans)
-			refcount_inc(&trans->use_count);
-		spin_unlock(&fs_info->trans_lock);
-
-		ASSERT(trans);
-		if (trans) {
-			if (atomic_dec_and_test(&trans->pending_ordered))
-				wake_up(&trans->pending_wait);
-			btrfs_put_transaction(trans);
-		}
-	}
-
 	spin_lock(&root->ordered_extent_lock);
 	list_del_init(&entry->root_extent_list);
 	root->nr_ordered_extents--;

fs/btrfs/ordered-data.h

@@ -56,8 +56,6 @@ struct btrfs_ordered_sum {
 				       * the isize. */
 #define BTRFS_ORDERED_TRUNCATED 8 /* Set when we have to truncate an extent */
 
-#define BTRFS_ORDERED_PENDING 9 /* We are waiting for this ordered extent to
-				  * complete in the current transaction. */
 #define BTRFS_ORDERED_REGULAR 10 /* Regular IO for COW */
 
 struct btrfs_ordered_extent {

fs/btrfs/transaction.c

@@ -233,14 +233,12 @@ static noinline int join_transaction(struct btrfs_fs_info *fs_info,
 	extwriter_counter_init(cur_trans, type);
 	init_waitqueue_head(&cur_trans->writer_wait);
 	init_waitqueue_head(&cur_trans->commit_wait);
-	init_waitqueue_head(&cur_trans->pending_wait);
 	cur_trans->state = TRANS_STATE_RUNNING;
 	/*
 	 * One for this trans handle, one so it will live on until we
 	 * commit the transaction.
 	 */
 	refcount_set(&cur_trans->use_count, 2);
-	atomic_set(&cur_trans->pending_ordered, 0);
 	cur_trans->flags = 0;
 	cur_trans->start_time = ktime_get_seconds();
 
@@ -1911,13 +1909,6 @@ static inline void btrfs_wait_delalloc_flush(struct btrfs_fs_info *fs_info)
 		btrfs_wait_ordered_roots(fs_info, U64_MAX, 0, (u64)-1);
 }
 
-static inline void
-btrfs_wait_pending_ordered(struct btrfs_transaction *cur_trans)
-{
-	wait_event(cur_trans->pending_wait,
-		   atomic_read(&cur_trans->pending_ordered) == 0);
-}
-
 int btrfs_commit_transaction(struct btrfs_trans_handle *trans)
 {
 	struct btrfs_fs_info *fs_info = trans->fs_info;
@@ -2052,8 +2043,6 @@ int btrfs_commit_transaction(struct btrfs_trans_handle *trans)
 
 	btrfs_wait_delalloc_flush(fs_info);
 
-	btrfs_wait_pending_ordered(cur_trans);
-
 	btrfs_scrub_pause(fs_info);
 	/*
 	 * Ok now we need to make sure to block out any other joins while we

fs/btrfs/transaction.h

@@ -39,7 +39,6 @@ struct btrfs_transaction {
 	 */
 	atomic_t num_writers;
 	refcount_t use_count;
-	atomic_t pending_ordered;
 
 	unsigned long flags;
 
@@ -51,7 +50,6 @@ struct btrfs_transaction {
 	time64_t start_time;
 	wait_queue_head_t writer_wait;
 	wait_queue_head_t commit_wait;
-	wait_queue_head_t pending_wait;
 	struct list_head pending_snapshots;
 	struct list_head pending_chunks;
 	struct list_head switch_commits;