From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1792673296; b=GO7JjGKOsTQPUB+6bibDActV3H/Dq3nJP9Fm9PI7HPD6MWzWIGVE642EOc/hBkBrfYLy n7O1PjbZ9/BNhl7iUI3IkHv9d16HAxQnybSli9iBErcTH76vEbBXu9bQpB8u+z7OscR4M lK8J3rhcKKY0I3LcuyxKh1mo8wACabqO88z9/TktO6EV8uO3mh+lw2SH9nQGpbrfL0HY1 HbXUzM5gish0kNab1nUsOiV3GSq6vdY11EPFbUBX0XloEX3hNRVMo+MdmBcU52bw7MZpn wLYJsiahnjzURRpeJdRi4yJCsM2NqqU6yKn8CNP6s3pOWXnlYN/nN/4lSDFxyeMIufg== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1792673296; h=Received:DKIM-Signature:Message-ID:From:Subject:Reply-To:To:Cc: In-Reply-To:References:Content-Type:Content-Transfer-Encoding:Date; bh=F5mdvUYsVNiOgtQvuxdVe/4OzAYQNK1lfEkEj7AIQdM=; b=bN+kVjkSLUTIdjdfo7W0vBBX2sOHx7arJ7KemVII649R0bVbJJECZTBJIuyRf2PQ/BIZ b+bpDWMzPTeZHdO5M+jr1iWKTm3yfJe27310PCtdHta/5wtjK2fDDw8kVIwC/XMpajxok qMQNzJg5tMoA30G7WXa++fbKJYn8kV4X4gpfI0Ey+IwgiZCoBcoo1xL84X/Dp87llImqv osgbb+62GBlfCE4AGL5DcxfiU5WIDpjf3t5jSj0JL9ji+CYsSPPbBIPyuZX+KQwseJC1Q egrQidg3ALYP36PZVUOBWXhP1PN/rjVKB0z4p/fW49xdXuIx6DyM1ex0WamyLrIIwjQ== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=XVEpoySu; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 1A09D606A319 for ; Thu, 22 Oct 2026 12:48:15 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=XVEpoySu Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7E7E11F000C1; Thu, 22 Oct 2026 12:48:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1792673295; bh=F5mdvUYsVNiOgtQvuxdVe/4OzAYQNK1lfEkEj7AIQdM=; h=From:Subject:Reply-To:To:Cc:In-Reply-To:References:Date; b=XVEpoySuj0oOFhvVguX02V6cfUi4kKoQr3f63/OUDvecKKgmX1oj3QQd/uqmV1uOW RilKuIiX09/7WFPuiwYUQvrk02a/OM3j6UzLQZSAaLg4SqjQLkbEWTGrelCY0pMAcu OA9j1EOAJnp2ftRno+gTwh9tPjYiyU8Lvrz5BeZT8uewS3J1glvq+7NQg7+QNarzjQ O1cpqON8TKhvSSpBW5X+PDIedY6e/0OfSo/AkSKGldA4cVvWqqtgLKUqgLtIKLPkJy ME+jpRflUPZpyXpUN4HidySV7/cxttP/4UhTyXmWrjHefjSUgWtDhbufKG93Y5KOqD EE/vdG9WJmLeA== Message-ID: From: sashiko-bot@kernel.org Subject: Re: [PATCH v2] ext4: skip eof zeroing when the zero range covers the eof block Reply-To: sashiko-reviews@lists.linux.dev To: "Baokun Li" , linux-ext4@vger.kernel.org Cc: tytso@mit.edu In-Reply-To: <20261022122625.1744363-1-libaokun@linux.alibaba.com> References: <20261022122625.1744363-1-libaokun@linux.alibaba.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Date: Thu, 22 Oct 2026 12:48:15 +0000 X-Mailing-List: linux-ext4@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list > ext4_zero_range() drops the page cache of the range before allocating, > to avoid exposing stale cached data. However, the dropped page can be > read back by the eof zeroing: >=20 > fallocate(fd, FALLOC_FL_ZERO_RANGE, 0, 4096) > ext4_zero_range() > ext4_truncate_page_cache_block_range(0, 4096) > truncate_pagecache_range(0, 4095) > truncate_inode_pages_range() > delete_from_page_cache_batch() # drops the page > ext4_alloc_file_blocks(..., 4096) > ext4_block_zero_eof(512, LLONG_MAX) # not block aligned > ext4_load_tail_bh() > __filemap_get_folio(FGP_WRITEBEGIN | FGP_ACCESSED) > # FGP_CREAT reads the dropped page back > [ ... ] >=20 > Fixes: c4602a1d09ec ("ext4: move zero partial block range functions out o= f active handle") > Fixes: f4265b8d32c4 ("ext4: add FALLOC_FL_WRITE_ZEROES support") > Cc: stable@vger.kernel.org > Signed-off-by: Baokun Li Sashiko has reviewed this patch and found no issues. --=20 Sashiko AI review =C2=B7 https://sashiko.dev/#/patchset/20261022122625.1744= 363-1-libaokun@linux.alibaba.com?part=3D1