From c8cc5b3e3fa154446eae9aa461aeb97bc5a07c09 Mon Sep 17 00:00:00 2001
From: Kent Overstreet <kent.overstreet@gmail.com>
Date: Tue, 26 Feb 2019 17:13:46 -0500
Subject: [PATCH] bcachefs: Don't get journal reservation until after we know
 insert will succeed

Checking if we can do the insert after getting the journal reservation
means potentially wasting space in the journal, which will break the new
pre reservation mechanism

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
---
 fs/bcachefs/btree_update_leaf.c | 88 +++++++++++++++++++--------------
 fs/bcachefs/journal.c           |  3 +-
 2 files changed, 52 insertions(+), 39 deletions(-)

diff --git a/fs/bcachefs/btree_update_leaf.c b/fs/bcachefs/btree_update_leaf.c
index 5555c6e1c7cf7..7043201ac6a3b 100644
--- a/fs/bcachefs/btree_update_leaf.c
+++ b/fs/bcachefs/btree_update_leaf.c
@@ -416,6 +416,25 @@ static inline int btree_trans_cmp(struct btree_insert_entry l,
 		btree_iter_cmp(l.iter, r.iter);
 }
 
+static bool btree_trans_relock(struct btree_insert *trans)
+{
+	struct btree_insert_entry *i;
+
+	trans_for_each_iter(trans, i)
+		return bch2_btree_iter_relock(i->iter);
+	return true;
+}
+
+static void btree_trans_unlock(struct btree_insert *trans)
+{
+	struct btree_insert_entry *i;
+
+	trans_for_each_iter(trans, i) {
+		bch2_btree_iter_unlock(i->iter);
+		break;
+	}
+}
+
 /* Normal update interface: */
 
 static enum btree_insert_ret
@@ -467,49 +486,12 @@ static inline int do_btree_insert_at(struct btree_insert *trans,
 	struct btree_iter *linked;
 	unsigned u64s;
 	int ret;
-
+retry:
 	trans_for_each_iter(trans, i)
 		BUG_ON(i->iter->uptodate >= BTREE_ITER_NEED_RELOCK);
 
-	/* reserve space for deferred updates */
-	__trans_for_each_entry(trans, i, i->deferred) {
-
-	}
-
 	memset(&trans->journal_res, 0, sizeof(trans->journal_res));
 
-	if (likely(!(trans->flags & BTREE_INSERT_JOURNAL_REPLAY))) {
-		u64s = 0;
-		trans_for_each_entry(trans, i)
-			u64s += jset_u64s(i->k->k.u64s);
-
-		while ((ret = bch2_journal_res_get(&c->journal,
-					&trans->journal_res, u64s,
-					JOURNAL_RES_GET_NONBLOCK)) == -EAGAIN) {
-			struct btree_iter *iter = NULL;
-
-			trans_for_each_iter(trans, i)
-				iter = i->iter;
-
-			if (iter)
-				bch2_btree_iter_unlock(iter);
-
-			ret = bch2_journal_res_get(&c->journal,
-					&trans->journal_res, u64s,
-					JOURNAL_RES_GET_CHECK);
-			if (ret)
-				return ret;
-
-			if (iter && !bch2_btree_iter_relock(iter)) {
-				trans_restart(" (iter relock after journal res get blocked)");
-				return -EINTR;
-			}
-		}
-
-		if (ret)
-			return ret;
-	}
-
 	multi_lock_write(c, trans);
 
 	if (race_fault()) {
@@ -537,6 +519,36 @@ static inline int do_btree_insert_at(struct btree_insert *trans,
 		}
 	}
 
+	if (likely(!(trans->flags & BTREE_INSERT_JOURNAL_REPLAY))) {
+		u64s = 0;
+		trans_for_each_entry(trans, i)
+			u64s += jset_u64s(i->k->k.u64s);
+
+		ret = bch2_journal_res_get(&c->journal,
+				&trans->journal_res, u64s,
+				JOURNAL_RES_GET_NONBLOCK);
+		if (likely(!ret))
+			goto got_journal_res;
+		if (ret != -EAGAIN)
+			goto out;
+
+		multi_unlock_write(trans);
+		btree_trans_unlock(trans);
+
+		ret = bch2_journal_res_get(&c->journal,
+				&trans->journal_res, u64s,
+				JOURNAL_RES_GET_CHECK);
+		if (ret)
+			return ret;
+
+		if (!btree_trans_relock(trans)) {
+			trans_restart(" (iter relock after journal res get blocked)");
+			return -EINTR;
+		}
+
+		goto retry;
+	}
+got_journal_res:
 	if (!(trans->flags & BTREE_INSERT_JOURNAL_REPLAY)) {
 		if (journal_seq_verify(c))
 			trans_for_each_entry(trans, i)
diff --git a/fs/bcachefs/journal.c b/fs/bcachefs/journal.c
index 3a60402440640..21e611cdaa06f 100644
--- a/fs/bcachefs/journal.c
+++ b/fs/bcachefs/journal.c
@@ -388,7 +388,8 @@ retry:
 		 * freezing:
 		 */
 		trace_journal_full(c);
-		bch2_journal_reclaim_work(&j->reclaim_work.work);
+		if (!(flags & JOURNAL_RES_GET_NONBLOCK))
+			bch2_journal_reclaim_work(&j->reclaim_work.work);
 		ret = -EAGAIN;
 	}
 
-- 
2.30.2