diff --git a/fs/buffer.c b/fs/buffer.c
index 22b43642ba574..dd2bd24126c09 100644
--- a/fs/buffer.c
+++ b/fs/buffer.c
@@ -2211,8 +2211,22 @@ void block_commit_write(struct folio *folio, size_t from, size_t to)
 			if (!buffer_uptodate(bh))
 				partial = true;
 		} else {
+			/*
+			 * Per the contract documented at set_buffer_uptodate()
+			 * in include/linux/buffer_head.h, callers must hold
+			 * BH_Lock to serialize against concurrent clears of
+			 * BH_Uptodate.  Holding only the folio lock is not
+			 * sufficient: a concurrent end_buffer_write_sync() on
+			 * the write-error path clears BH_Uptodate while
+			 * holding BH_Lock; without BH_Lock here the clear can
+			 * land between set_buffer_uptodate() and
+			 * mark_buffer_dirty(), tripping the WARN_ON_ONCE in
+			 * mark_buffer_dirty().
+			 */
+			lock_buffer(bh);
 			set_buffer_uptodate(bh);
 			mark_buffer_dirty(bh);
+			unlock_buffer(bh);
 		}
 		if (buffer_new(bh))
 			clear_buffer_new(bh);