From: Jan Kara <jack@suse.cz>
Date: Wed, 29 Mar 2023 17:49:32 +0200
Subject: [PATCH] jdb2: Don't refuse invalidation of already invalidated
 buffers
References: bsc#1012628
Patch-mainline: 6.3.2
Git-commit: bd159398a2d2234de07d310132865706964aaaa7

[ Upstream commit bd159398a2d2234de07d310132865706964aaaa7 ]

When invalidating buffers under the partial tail page,
jbd2_journal_invalidate_folio() returns -EBUSY if the buffer is part of
the committing transaction as we cannot safely modify buffer state.
However if the buffer is already invalidated (due to previous
invalidation attempts from ext4_wait_for_tail_page_commit()), there's
nothing to do and there's no point in returning -EBUSY. This fixes
occasional warnings from ext4_journalled_invalidate_folio() triggered by
generic/051 fstest when blocksize < pagesize.

Fixes: 53e872681fed ("ext4: fix deadlock in journal_unmap_buffer()")
Signed-off-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20230329154950.19720-1-jack@suse.cz
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
---
 fs/jbd2/transaction.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/fs/jbd2/transaction.c b/fs/jbd2/transaction.c
index 15de1385..18611241 100644
--- a/fs/jbd2/transaction.c
+++ b/fs/jbd2/transaction.c
@@ -2387,6 +2387,9 @@ static int journal_unmap_buffer(journal_t *journal, struct buffer_head *bh,
 			spin_unlock(&jh->b_state_lock);
 			write_unlock(&journal->j_state_lock);
 			jbd2_journal_put_journal_head(jh);
+			/* Already zapped buffer? Nothing to do... */
+			if (!bh->b_bdev)
+				return 0;
 			return -EBUSY;
 		}
 		/*
-- 
2.35.3