From patchwork Sat Sep 5 05:20:22 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Gabriel Krisman Bertazi X-Patchwork-Id: 11758789 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 07E6E618 for ; Sat, 5 Sep 2020 05:20:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id ED0A42137B for ; Sat, 5 Sep 2020 05:20:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726403AbgIEFUj (ORCPT ); Sat, 5 Sep 2020 01:20:39 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55970 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726366AbgIEFUj (ORCPT ); Sat, 5 Sep 2020 01:20:39 -0400 Received: from bhuna.collabora.co.uk (bhuna.collabora.co.uk [IPv6:2a00:1098:0:82:1000:25:2eeb:e3e3]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 16B20C061244 for ; Fri, 4 Sep 2020 22:20:36 -0700 (PDT) Received: from [127.0.0.1] (localhost [127.0.0.1]) (Authenticated sender: krisman) with ESMTPSA id C987729B717 From: Gabriel Krisman Bertazi To: viro@zeniv.linux.org.uk Cc: linux-fsdevel@vger.kernel.org, jack@suse.cz, khazhy@google.com, Gabriel Krisman Bertazi , kernel@collabora.com Subject: [PATCH v3 2/3] direct-io: don't force writeback for reads beyond EOF Date: Sat, 5 Sep 2020 01:20:22 -0400 Message-Id: <20200905052023.3719585-3-krisman@collabora.com> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20200905052023.3719585-1-krisman@collabora.com> References: <20200905052023.3719585-1-krisman@collabora.com> MIME-Version: 1.0 Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org If a DIO read starts past EOF, the kernel won't attempt it, so we don't need to flush dirty pages before failing the syscall. Suggested-by: Jan Kara Reviewed-by: Jan Kara Signed-off-by: Gabriel Krisman Bertazi --- fs/direct-io.c | 24 +++++++++++------------- 1 file changed, 11 insertions(+), 13 deletions(-) diff --git a/fs/direct-io.c b/fs/direct-io.c index 6c11db1cec27..c17efe58f1c9 100644 --- a/fs/direct-io.c +++ b/fs/direct-io.c @@ -1188,19 +1188,9 @@ do_blockdev_direct_IO(struct kiocb *iocb, struct inode *inode, memset(dio, 0, offsetof(struct dio, pages)); dio->flags = flags; - if (dio->flags & DIO_LOCKING) { - if (iov_iter_rw(iter) == READ) { - struct address_space *mapping = - iocb->ki_filp->f_mapping; - - /* will be released by direct_io_worker */ - inode_lock(inode); - - retval = filemap_write_and_wait_range(mapping, offset, - end - 1); - if (retval) - goto fail_dio; - } + if (dio->flags & DIO_LOCKING && iov_iter_rw(iter) == READ) { + /* will be released by direct_io_worker */ + inode_lock(inode); } /* Once we sampled i_size check for reads beyond EOF */ @@ -1210,6 +1200,14 @@ do_blockdev_direct_IO(struct kiocb *iocb, struct inode *inode, goto fail_dio; } + if (dio->flags & DIO_LOCKING && iov_iter_rw(iter) == READ) { + struct address_space *mapping = iocb->ki_filp->f_mapping; + + retval = filemap_write_and_wait_range(mapping, offset, end - 1); + if (retval) + goto fail_dio; + } + /* * For file extending writes updating i_size before data writeouts * complete can expose uninitialized blocks in dumb filesystems. From patchwork Sat Sep 5 05:20:23 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Gabriel Krisman Bertazi X-Patchwork-Id: 11758791 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 51398618 for ; Sat, 5 Sep 2020 05:20:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3E7F020E65 for ; Sat, 5 Sep 2020 05:20:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726421AbgIEFUk (ORCPT ); Sat, 5 Sep 2020 01:20:40 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55978 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726366AbgIEFUj (ORCPT ); Sat, 5 Sep 2020 01:20:39 -0400 Received: from bhuna.collabora.co.uk (bhuna.collabora.co.uk [IPv6:2a00:1098:0:82:1000:25:2eeb:e3e3]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3DF5DC061245 for ; Fri, 4 Sep 2020 22:20:39 -0700 (PDT) Received: from [127.0.0.1] (localhost [127.0.0.1]) (Authenticated sender: krisman) with ESMTPSA id C388D29B18C From: Gabriel Krisman Bertazi To: viro@zeniv.linux.org.uk Cc: linux-fsdevel@vger.kernel.org, jack@suse.cz, khazhy@google.com, Gabriel Krisman Bertazi , kernel@collabora.com, Jamie Liu Subject: [PATCH v3 3/3] direct-io: defer alignment check until after the EOF check Date: Sat, 5 Sep 2020 01:20:23 -0400 Message-Id: <20200905052023.3719585-4-krisman@collabora.com> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20200905052023.3719585-1-krisman@collabora.com> References: <20200905052023.3719585-1-krisman@collabora.com> MIME-Version: 1.0 Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org Prior to commit 9fe55eea7e4b ("Fix race when checking i_size on direct i/o read"), an unaligned direct read past end of file would trigger EOF, since generic_file_aio_read detected this read-at-EOF condition and skipped the direct IO read entirely, returning 0. After that change, the read now reaches dio_generic, which detects the misalignment and returns EINVAL. This consolidates the generic direct-io to follow the same behavior of filesystems. Apparently, this fix will only affect ocfs2 since other filesystems do this verification before calling do_blockdev_direct_IO, with the exception of f2fs, which has the same bug, but is fixed in the next patch. it can be verified by a read loop on a file that does a partial read before EOF (On file that doesn't end at an aligned address). The following code fails on an unaligned file on filesystems without prior validation without this patch, but not on btrfs, ext4, and xfs. while (done < total) { ssize_t delta = pread(fd, buf + done, total - done, off + done); if (!delta) break; ... } Fix this regression by moving the misalignment check to after the EOF check added by commit 74cedf9b6c60 ("direct-io: Fix negative return from dio read beyond eof"). Based on a patch by Jamie Liu. Reported-by: Jamie Liu Signed-off-by: Gabriel Krisman Bertazi Reviewed-by: Jan Kara --- fs/direct-io.c | 16 ++++++++-------- 1 file changed, 8 insertions(+), 8 deletions(-) diff --git a/fs/direct-io.c b/fs/direct-io.c index c17efe58f1c9..82838cca934b 100644 --- a/fs/direct-io.c +++ b/fs/direct-io.c @@ -1165,14 +1165,6 @@ do_blockdev_direct_IO(struct kiocb *iocb, struct inode *inode, * the early prefetch in the caller enough time. */ - if (align & blocksize_mask) { - if (bdev) - blkbits = blksize_bits(bdev_logical_block_size(bdev)); - blocksize_mask = (1 << blkbits) - 1; - if (align & blocksize_mask) - return -EINVAL; - } - /* watch out for a 0 len io from a tricksy fs */ if (iov_iter_rw(iter) == READ && !count) return 0; @@ -1200,6 +1192,14 @@ do_blockdev_direct_IO(struct kiocb *iocb, struct inode *inode, goto fail_dio; } + if (align & blocksize_mask) { + if (bdev) + blkbits = blksize_bits(bdev_logical_block_size(bdev)); + blocksize_mask = (1 << blkbits) - 1; + if (align & blocksize_mask) + goto fail_dio; + } + if (dio->flags & DIO_LOCKING && iov_iter_rw(iter) == READ) { struct address_space *mapping = iocb->ki_filp->f_mapping;