From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id D752BC7618A for ; Mon, 20 Mar 2023 16:20:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232290AbjCTQUn (ORCPT ); Mon, 20 Mar 2023 12:20:43 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55384 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233178AbjCTQT6 (ORCPT ); Mon, 20 Mar 2023 12:19:58 -0400 Received: from mail-pj1-x1030.google.com (mail-pj1-x1030.google.com [IPv6:2607:f8b0:4864:20::1030]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5B140298D4 for ; Mon, 20 Mar 2023 09:11:46 -0700 (PDT) Received: by mail-pj1-x1030.google.com with SMTP id j13so12640432pjd.1 for ; Mon, 20 Mar 2023 09:11:46 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; t=1679328705; h=in-reply-to:subject:cc:to:from:message-id:date:from:to:cc:subject :date:message-id:reply-to; bh=Xs85zXA0FLZRHe7v0i3MbFeGMJjNZb7cHoH6pL8h2Mw=; b=SlBkrd3a3KCNec2FChzCjhI2tTU0iEFcypholsUZMEpr+wkTW6G8dDqensjYH71yN9 +nEGpSejWUsG7g3PStzPn2ILLZmit6pCEHp4XAvZyrElhb+txeNFn2om4e0uVU1dXbZ/ I6uE4us4ZDZudqCTU7aDhZP98SZl3GbLMSeqibw7WRCHT4HAhDYo3RVd0USSw/jDTkMu K80tse3mAE8pIueXNAY4jRAiicsAAdJXNKRS8W3laSG0WRpJ3tsYqXbeCKaiihYhLV+a gC+rPZ5huWWM1oBBMDj/Zr38fh4bBgwzRCknWP+LyKXfoy/PxZKZOWEpBlFYN4sZfwYE ZhVA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; t=1679328705; h=in-reply-to:subject:cc:to:from:message-id:date:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=Xs85zXA0FLZRHe7v0i3MbFeGMJjNZb7cHoH6pL8h2Mw=; b=YO6Z0xXSdhqmJh0Y4z6ZwkzK08m9R/1RHd4eRipTTwjGCFLY5dd3oO54bbL5RlHBcA AM/+PreBWj10lQrKOP4mhG9+uHPxTMP6I4H839bXi7ToDwv4Him9pwFebBtKzHkGjd0c mwNuiowzNq+N08dS/LBekTd0eqMV442vT2oUqYndIc7Pi4GgjDrgLXBXtCrW1aLIJGuR nGSPVHO0LFiIN6iMlARTe9RQ+Q+WLEb+fCE5lBbwK8cblYVFtTv8JOFyEzBBoGyzn1Ao +FYTx3BVT35svkoCvwWgE6F2A6ig0wKdGCwSzjIVPnjf+kxEt9QIj38ZyRzH9u61X9Ml B5Pg== X-Gm-Message-State: AO0yUKURrAkbBz4NJiUEHDvKomP24zjwscFyGxHUE4Oo/ADF/4J0hevo ptljgErrYKLSnO0MR16XF/Yr3+GpWINKxw== X-Google-Smtp-Source: AK7set/dk11fvFG53i/glaHTQimV/h1JnY1DP0NCrQOqfwxYSVLnqtWnVbHY4fVYSHjCxB5gZkCpAw== X-Received: by 2002:a17:902:f243:b0:1a1:a5d9:146d with SMTP id j3-20020a170902f24300b001a1a5d9146dmr11509080plc.65.1679328704886; Mon, 20 Mar 2023 09:11:44 -0700 (PDT) Received: from rh-tp ([2406:7400:63:469f:1474:7c59:3a57:aab6]) by smtp.gmail.com with ESMTPSA id x13-20020a1709027c0d00b001a06677948dsm6891969pll.293.2023.03.20.09.11.42 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 20 Mar 2023 09:11:44 -0700 (PDT) Date: Mon, 20 Mar 2023 21:41:25 +0530 Message-Id: <87ttyfz9le.fsf@doe.com> From: Ritesh Harjani (IBM) To: "Darrick J. Wong" Cc: Jan Kara , linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, lsf-pc@lists.linux-foundation.org Subject: Re: [RFCv1][WIP] ext2: Move direct-io to use iomap In-Reply-To: <20230316154143.GA11351@frogsfrogsfrogs> Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org "Darrick J. Wong" writes: > On Thu, Mar 16, 2023 at 08:10:29PM +0530, Ritesh Harjani (IBM) wrote: >> [DO NOT MERGE] [WORK-IN-PROGRESS] >> >> Hello Jan, >> >> This is an initial version of the patch set which I wanted to share >> before today's call. This is still work in progress but atleast passes >> the set of test cases which I had kept for dio testing (except 1 from my >> list). >> >> Looks like there won't be much/any changes required from iomap side to >> support ext2 moving to iomap apis. >> >> I will be doing some more testing specifically test generic/083 which is >> occassionally failing in my testing. >> Also once this is stabilized, I can do some performance testing too if you >> feel so. Last I remembered we saw some performance regressions when ext4 >> moved to iomap for dio. >> >> PS: Please ignore if there are some silly mistakes. As I said, I wanted >> to get this out before today's discussion. :) >> >> Thanks for your help!! >> >> Signed-off-by: Ritesh Harjani (IBM) >> --- >> fs/ext2/ext2.h | 1 + >> fs/ext2/file.c | 114 ++++++++++++++++++++++++++++++++++++++++++++++++ >> fs/ext2/inode.c | 20 +-------- >> 3 files changed, 117 insertions(+), 18 deletions(-) >> >> diff --git a/fs/ext2/ext2.h b/fs/ext2/ext2.h >> index cb78d7dcfb95..cb5e309fe040 100644 >> --- a/fs/ext2/ext2.h >> +++ b/fs/ext2/ext2.h >> @@ -753,6 +753,7 @@ extern unsigned long ext2_count_free (struct buffer_head *, unsigned); >> extern struct inode *ext2_iget (struct super_block *, unsigned long); >> extern int ext2_write_inode (struct inode *, struct writeback_control *); >> extern void ext2_evict_inode(struct inode *); >> +extern void ext2_write_failed(struct address_space *mapping, loff_t to); >> extern int ext2_get_block(struct inode *, sector_t, struct buffer_head *, int); >> extern int ext2_setattr (struct mnt_idmap *, struct dentry *, struct iattr *); >> extern int ext2_getattr (struct mnt_idmap *, const struct path *, >> diff --git a/fs/ext2/file.c b/fs/ext2/file.c >> index 6b4bebe982ca..7a8561304559 100644 >> --- a/fs/ext2/file.c >> +++ b/fs/ext2/file.c >> @@ -161,12 +161,123 @@ int ext2_fsync(struct file *file, loff_t start, loff_t end, int datasync) >> return ret; >> } >> >> +static ssize_t ext2_dio_read_iter(struct kiocb *iocb, struct iov_iter *to) >> +{ >> + struct file *file = iocb->ki_filp; >> + struct inode *inode = file->f_mapping->host; >> + ssize_t ret; >> + >> + inode_lock_shared(inode); >> + ret = iomap_dio_rw(iocb, to, &ext2_iomap_ops, NULL, 0, NULL, 0); >> + inode_unlock_shared(inode); >> + >> + return ret; >> +} >> + >> +static int ext2_dio_write_end_io(struct kiocb *iocb, ssize_t size, >> + int error, unsigned int flags) >> +{ >> + loff_t pos = iocb->ki_pos; >> + struct inode *inode = file_inode(iocb->ki_filp); >> + >> + if (error) >> + return error; >> + >> + pos += size; >> + if (pos > i_size_read(inode)) >> + i_size_write(inode, pos); >> + >> + return 0; >> +} >> + >> +static const struct iomap_dio_ops ext2_dio_write_ops = { >> + .end_io = ext2_dio_write_end_io, >> +}; >> + >> +static ssize_t ext2_dio_write_iter(struct kiocb *iocb, struct iov_iter *from) >> +{ >> + struct file *file = iocb->ki_filp; >> + struct inode *inode = file->f_mapping->host; >> + ssize_t ret; >> + unsigned int flags; >> + unsigned long blocksize = inode->i_sb->s_blocksize; >> + loff_t offset = iocb->ki_pos; >> + loff_t count = iov_iter_count(from); >> + >> + >> + inode_lock(inode); >> + ret = generic_write_checks(iocb, from); >> + if (ret <= 0) >> + goto out_unlock; >> + ret = file_remove_privs(file); >> + if (ret) >> + goto out_unlock; >> + ret = file_update_time(file); >> + if (ret) >> + goto out_unlock; > > kiocb_modified() instead of calling file_remove_privs? Yes, looks likle it is a replacement for file_remove_privs and file_update_time(). >> + >> + /* >> + * We pass IOMAP_DIO_NOSYNC because otherwise iomap_dio_rw() >> + * calls for generic_write_sync in iomap_dio_complete(). >> + * Since ext2_fsync nmust be called w/o inode lock, >> + * hence we pass IOMAP_DIO_NOSYNC and handle generic_write_sync() >> + * ourselves. >> + */ >> + flags = IOMAP_DIO_NOSYNC; >> + >> + /* use IOMAP_DIO_FORCE_WAIT for unaligned of extending writes */ >> + if (iocb->ki_pos + iov_iter_count(from) > i_size_read(inode) || >> + (!IS_ALIGNED(iocb->ki_pos | iov_iter_alignment(from), blocksize))) >> + flags |= IOMAP_DIO_FORCE_WAIT; >> + >> + ret = iomap_dio_rw(iocb, from, &ext2_iomap_ops, &ext2_dio_write_ops, >> + flags, NULL, 0); >> + >> + if (ret == -ENOTBLK) >> + ret = 0; >> + >> + if (ret < 0 && ret != -EIOCBQUEUED) >> + ext2_write_failed(inode->i_mapping, offset + count); >> + >> + /* handle case for partial write or fallback to buffered write */ >> + if (ret >= 0 && iov_iter_count(from)) { >> + loff_t pos, endbyte; >> + ssize_t status; >> + ssize_t ret2; >> + >> + pos = iocb->ki_pos; >> + status = generic_perform_write(iocb, from); >> + if (unlikely(status < 0)) { >> + ret = status; >> + goto out_unlock; >> + } >> + endbyte = pos + status - 1; >> + ret2 = filemap_write_and_wait_range(inode->i_mapping, pos, >> + endbyte); >> + if (ret2 == 0) { >> + iocb->ki_pos = endbyte + 1; >> + ret += status; >> + invalidate_mapping_pages(inode->i_mapping, >> + pos >> PAGE_SHIFT, >> + endbyte >> PAGE_SHIFT); >> + } >> + } > > (Why not fall back to the actual buffered write path?) > Because then we can handle everything related to DIO in ext4_dio_file_write() itself e.g. As per the semantics of DIO we should ensure that page-cache pages are written to disk and invalidated before returning (filemap_write_and_wait_range() and invalidate_mapping_pages()) > Otherwise this looks like a reasonable first start. Thanks! -ritesh