From patchwork Tue Aug 27 05:09:48 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Christoph Hellwig X-Patchwork-Id: 13778850 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id B724671B3A; Tue, 27 Aug 2024 05:10:33 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.137.202.133 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1724735435; cv=none; b=tzBE1d/p6agnFgZpBvZ9CAr1+E7vQ9W2bqT3Ao5rqnOqi5XVnrgio3h3enaFaKCvnP1hZB86+NNd49iEQAuiKH5ZytEZF8jdAoRvLtCW9oatnwKutTfgZjtZIxub6lIu4QVWCpazf7Jb7l+TnHtD1/V+3CElEcYtxsC3OCQPGRI= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1724735435; c=relaxed/simple; bh=S4t0YJTaUsVaXaw2toaWNEboaIubRMWMnQ8nWtOZio4=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=PnrkzLzw2mJ3MuLYoMsXJdMVjmJPx3qDZwM2BhaBeUJbp20uXfPM29AHiX22asp1e3b1dw9+Ansihk0bIYVnBgw40vf3JOAeNvtTsJyeRD51EYj+lcqKBNy3vSpas8XV85d7eIq8bYFQVbCdLg7T39BL6LEUymF0MwHqUH8gBnE= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=lst.de; spf=none smtp.mailfrom=bombadil.srs.infradead.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b=Oqh43pau; arc=none smtp.client-ip=198.137.202.133 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=lst.de Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=bombadil.srs.infradead.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="Oqh43pau" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20210309; h=Content-Transfer-Encoding: MIME-Version:References:In-Reply-To:Message-ID:Date:Subject:Cc:To:From:Sender :Reply-To:Content-Type:Content-ID:Content-Description; bh=gaLvMRbUaWGWc7eCBYjA9sjU57Va5YYkXOlLMnWX0pk=; b=Oqh43pauk3NkAmTm96dahQtRGR hDfALRqBZgH9rjyccbuVhjvttLY6i0uuTNn425m7DhxHec09u6GagJ3UTkv7CjVlLVCYwCio8lTAF TWd2girRs+9pyrvyDAH8bs2ZqjKvBIUO7SKahkHIjm1b3MwPdiWxSFgo3YLvCO0lKqfPWn0ISY2MD BPBOfBSAUyoomiPFEOpztzRJFPmSw8e2+Jcg+DnXKgsKXcL/e/QbctRhFbv1rRt2onWsvwibJBWeQ 038nyv70tg6e+Dhf1dy83fr+KZKDS/U7xDpMIaeeDUzRG6YiHPbpbhRgJ65WG2hIJAXoZMfkp0/67 JQ8J7OXA==; Received: from 2a02-8389-2341-5b80-0483-5781-2c2b-8fb4.cable.dynamic.v6.surfer.at ([2a02:8389:2341:5b80:483:5781:2c2b:8fb4] helo=localhost) by bombadil.infradead.org with esmtpsa (Exim 4.97.1 #2 (Red Hat Linux)) id 1sioTQ-00000009oqB-3GIT; Tue, 27 Aug 2024 05:10:33 +0000 From: Christoph Hellwig To: Chandan Babu R , Christian Brauner , "Darrick J. Wong" Cc: linux-xfs@vger.kernel.org, linux-fsdevel@vger.kernel.org Subject: [PATCH 01/10] iomap: handle a post-direct I/O invalidate race in iomap_write_delalloc_release Date: Tue, 27 Aug 2024 07:09:48 +0200 Message-ID: <20240827051028.1751933-2-hch@lst.de> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20240827051028.1751933-1-hch@lst.de> References: <20240827051028.1751933-1-hch@lst.de> Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html When direct I/O completions invalidates the page cache it holds neither the i_rwsem nor the invalidate_lock so it can be racing with iomap_write_delalloc_release. If the search for the end of the region that contains data returns the start offset we hit such a race and just need to look for the end of the newly created hole instead. Signed-off-by: Christoph Hellwig Reviewed-by: Darrick J. Wong Reviewed-by: Darrick J. Wong --- fs/iomap/buffered-io.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c index f420c53d86acc5..69a931de1979b9 100644 --- a/fs/iomap/buffered-io.c +++ b/fs/iomap/buffered-io.c @@ -1241,7 +1241,15 @@ static int iomap_write_delalloc_release(struct inode *inode, error = data_end; goto out_unlock; } - WARN_ON_ONCE(data_end <= start_byte); + + /* + * If we race with post-direct I/O invalidation of the page cache, + * there might be no data left at start_byte. + */ + if (data_end == start_byte) + continue; + + WARN_ON_ONCE(data_end < start_byte); WARN_ON_ONCE(data_end > scan_end_byte); error = iomap_write_delalloc_scan(inode, &punch_start_byte,