From: Jan Kara <jack@suse.cz>
Date: Fri, 9 Aug 2019 14:42:31 +0200
Subject: jbd2: Don't call __bforget() unnecessarily
Patch-mainline: v5.5-rc1
Git-commit: 2e710ff03fc4599059eeda68c8de2383e65af825
References: bsc#1162702

jbd2_journal_forget() jumps to 'not_jbd' branch which calls __bforget()
in cases where the buffer is clean which is pointless. In case of failed
assertion, it can be even argued that it is safer not to touch buffer's
dirty bits. Also logically it makes more sense to just jump to 'drop'
and that will make logic also simpler when we switch bh_state_lock to a
spinlock.

Signed-off-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20190809124233.13277-6-jack@suse.cz
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Acked-by: Daniel Wagner <dwagner@suse.de>
---
 fs/jbd2/transaction.c |    9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)

--- a/fs/jbd2/transaction.c
+++ b/fs/jbd2/transaction.c
@@ -1547,7 +1547,7 @@ int jbd2_journal_forget (handle_t *handl
 	if (!J_EXPECT_JH(jh, !jh->b_committed_data,
 			 "inconsistent data on disk")) {
 		err = -EIO;
-		goto not_jbd;
+		goto drop;
 	}
 
 	/* keep track of whether or not this transaction modified us */
@@ -1637,7 +1637,7 @@ int jbd2_journal_forget (handle_t *handl
 		if (!jh->b_cp_transaction) {
 			JBUFFER_TRACE(jh, "belongs to none transaction");
 			spin_unlock(&journal->j_list_lock);
-			goto not_jbd;
+			goto drop;
 		}
 
 		/*
@@ -1647,7 +1647,7 @@ int jbd2_journal_forget (handle_t *handl
 		if (!buffer_dirty(bh)) {
 			__jbd2_journal_remove_checkpoint(jh);
 			spin_unlock(&journal->j_list_lock);
-			goto not_jbd;
+			goto drop;
 		}
 
 		/*
@@ -1660,10 +1660,9 @@ int jbd2_journal_forget (handle_t *handl
 		__jbd2_journal_file_buffer(jh, transaction, BJ_Forget);
 		spin_unlock(&journal->j_list_lock);
 	}
-
+drop:
 	jbd_unlock_bh_state(bh);
 	__brelse(bh);
-drop:
 	if (drop_reserve) {
 		/* no need to reserve log space for this block -bzzz */
 		handle->h_buffer_credits++;