From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx2.suse.de ([195.135.220.15]:46512 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753279AbeDUXTb (ORCPT ); Sat, 21 Apr 2018 19:19:31 -0400 Date: Sat, 21 Apr 2018 15:03:09 +0200 From: Jan Kara To: Dave Chinner Cc: linux-xfs@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-block@vger.kernel.org, hch@lst.de, rdorr@microsoft.com Subject: Re: [PATCH 2/4] iomap: iomap_dio_rw() handles all sync writes Message-ID: <20180421130309.efivmjo5ald2jchv@quack2.suse.cz> References: <20180418040828.18165-1-david@fromorbit.com> <20180418040828.18165-3-david@fromorbit.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180418040828.18165-3-david@fromorbit.com> Sender: linux-fsdevel-owner@vger.kernel.org List-ID: On Wed 18-04-18 14:08:26, Dave Chinner wrote: > From: Dave Chinner > > Currently iomap_dio_rw() only handles (data)sync write completions > for AIO. This means we can't optimised non-AIO IO to minimise device > flushes as we can't tell the caller whether a flush is required or > not. > > To solve this problem and enable further optimisations, make > iomap_dio_rw responsible for data sync behaviour for all IO, not > just AIO. > > In doing so, the sync operation is now accounted as part of the DIO > IO by inode_dio_end(), hence post-IO data stability updates will no > long race against operations that serialise via inode_dio_wait() > such as truncate or hole punch. > > Signed-Off-By: Dave Chinner > Reviewed-by: Christoph Hellwig Looks good to me. You can add: Reviewed-by: Jan Kara Honza > --- > fs/iomap.c | 22 +++++++++++++++------- > fs/xfs/xfs_file.c | 5 ----- > 2 files changed, 15 insertions(+), 12 deletions(-) > > diff --git a/fs/iomap.c b/fs/iomap.c > index afd163586aa0..1f59c2d9ade6 100644 > --- a/fs/iomap.c > +++ b/fs/iomap.c > @@ -685,6 +685,7 @@ EXPORT_SYMBOL_GPL(iomap_seek_data); > * Private flags for iomap_dio, must not overlap with the public ones in > * iomap.h: > */ > +#define IOMAP_DIO_NEED_SYNC (1 << 29) > #define IOMAP_DIO_WRITE (1 << 30) > #define IOMAP_DIO_DIRTY (1 << 31) > > @@ -759,6 +760,13 @@ static ssize_t iomap_dio_complete(struct iomap_dio *dio) > dio_warn_stale_pagecache(iocb->ki_filp); > } > > + /* > + * If this is a DSYNC write, make sure we push it to stable storage now > + * that we've written data. > + */ > + if (ret > 0 && (dio->flags & IOMAP_DIO_NEED_SYNC)) > + ret = generic_write_sync(iocb, ret); > + > inode_dio_end(file_inode(iocb->ki_filp)); > kfree(dio); > > @@ -768,14 +776,8 @@ static ssize_t iomap_dio_complete(struct iomap_dio *dio) > static void iomap_dio_complete_work(struct work_struct *work) > { > struct iomap_dio *dio = container_of(work, struct iomap_dio, aio.work); > - struct kiocb *iocb = dio->iocb; > - bool is_write = (dio->flags & IOMAP_DIO_WRITE); > - ssize_t ret; > > - ret = iomap_dio_complete(dio); > - if (is_write && ret > 0) > - ret = generic_write_sync(iocb, ret); > - iocb->ki_complete(iocb, ret, 0); > + dio->iocb->ki_complete(dio->iocb, iomap_dio_complete(dio), 0); > } > > /* > @@ -961,6 +963,10 @@ iomap_dio_actor(struct inode *inode, loff_t pos, loff_t length, > return copied; > } > > +/* > + * iomap_dio_rw() always completes O_[D]SYNC writes regardless of whether the IO > + * is being issued as AIO or not. > + */ > ssize_t > iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter, > const struct iomap_ops *ops, iomap_dio_end_io_t end_io) > @@ -1006,6 +1012,8 @@ iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter, > dio->flags |= IOMAP_DIO_DIRTY; > } else { > dio->flags |= IOMAP_DIO_WRITE; > + if (iocb->ki_flags & IOCB_DSYNC) > + dio->flags |= IOMAP_DIO_NEED_SYNC; > flags |= IOMAP_WRITE; > } > > diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c > index 6f15027661b6..0c4b8313d544 100644 > --- a/fs/xfs/xfs_file.c > +++ b/fs/xfs/xfs_file.c > @@ -570,11 +570,6 @@ xfs_file_dio_aio_write( > * complete fully or fail. > */ > ASSERT(ret < 0 || ret == count); > - > - if (ret > 0) { > - /* Handle various SYNC-type writes */ > - ret = generic_write_sync(iocb, ret); > - } > return ret; > } > > -- > 2.16.1 > -- Jan Kara SUSE Labs, CR