From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 8F2302FFFA4; Mon, 19 Jan 2026 17:45:38 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1768844738; cv=none; b=paF1/pjpEKrRTxHWaJBW1e3aSkeMQ5h35Xthx0Rtw+Z6VWA+2GMEJZmTuMLzv444LUeF3xGc7IKUx9sp6aZXJ44uJHRZF9P2WSRsAm3eYYHhCdJET0P6CNzXalzJCxJV+yt272TdZ7cpxQxcDr881us1BWc1c8SH0X5zY4c9GXE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1768844738; c=relaxed/simple; bh=GPpH+lrbGOkUO+HU9Chxi5Q9b/lVJMf37L9lUr7ORSQ=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=ZAt7XMeyn6XaRzwLVKJoySz9CMWaaF+M0sYjmyeivm6CfZEfQ/ujXe2Pa2pwdcaLbcehCm6iNDjjwjZHdibs2GyPOsrwPiIgwRs+Xabk+k+37MmCxPC+63lstYn5pgjUqY1c+Vn1/M8z47I1VEFRc11trDZd4uT0jF1mR65tX3s= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=C5XRitry; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="C5XRitry" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 264B7C116C6; Mon, 19 Jan 2026 17:45:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1768844738; bh=GPpH+lrbGOkUO+HU9Chxi5Q9b/lVJMf37L9lUr7ORSQ=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=C5XRitryyvB369UvpUUl4ZByVUzZnV/Os70U8sb5qN7qyvUay3fkYqXuMerG1KiaK uiCUCQPF45PW7tt+hEkQzAKhgO2IXjJlJGMPNTIhEbYTIEDRde7TbzUW7Odwa6CiU0 RYgOM/1POMEt5PwTYJmmkKJ2iPsOrShfOjrk4tKwSREc4rPj5kvQv+/m8qkx1xYOoq GfbiOA5x4FLcNJ3KgUtHdwWYiCpSHNMLSQdDRWPLKD2/Pf4n9wXkJhSCG/7GMnVUS8 xboHbYe45dKIdeVZUtIKXcTbU53+OBiVlxyAlKjzZbwJ+7XYrwiro3TzMUuc86s/u6 7JcdUFJL9s1kg== Date: Mon, 19 Jan 2026 09:45:37 -0800 From: "Darrick J. Wong" To: Christoph Hellwig Cc: Jens Axboe , Christian Brauner , Carlos Maiolino , Qu Wenruo , Al Viro , linux-block@vger.kernel.org, linux-xfs@vger.kernel.org, linux-fsdevel@vger.kernel.org Subject: Re: [PATCH 14/14] xfs: use bounce buffering direct I/O when the device requires stable pages Message-ID: <20260119174537.GD15551@frogsfrogsfrogs> References: <20260119074425.4005867-1-hch@lst.de> <20260119074425.4005867-15-hch@lst.de> Precedence: bulk X-Mailing-List: linux-block@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260119074425.4005867-15-hch@lst.de> On Mon, Jan 19, 2026 at 08:44:21AM +0100, Christoph Hellwig wrote: > Fix direct I/O on devices that require stable pages by asking iomap > to bounce buffer. To support this, ioends are used for direct reads > in this case to provide a user context for copying data back from the > bounce buffer. > > This fixes qemu when used on devices using T10 protection information > and probably other cases like iSCSI using data digests. > > Signed-off-by: Christoph Hellwig Ahaha, I forgot in the last round that s_dio_done_wq is not at all the place for doing bio completions. Reviewed-by: "Darrick J. Wong" --D > --- > fs/xfs/xfs_aops.c | 8 ++++++-- > fs/xfs/xfs_file.c | 41 ++++++++++++++++++++++++++++++++++++++--- > 2 files changed, 44 insertions(+), 5 deletions(-) > > diff --git a/fs/xfs/xfs_aops.c b/fs/xfs/xfs_aops.c > index 56a544638491..c3c1e149fff4 100644 > --- a/fs/xfs/xfs_aops.c > +++ b/fs/xfs/xfs_aops.c > @@ -103,7 +103,7 @@ xfs_ioend_put_open_zones( > * IO write completion. > */ > STATIC void > -xfs_end_ioend( > +xfs_end_ioend_write( > struct iomap_ioend *ioend) > { > struct xfs_inode *ip = XFS_I(ioend->io_inode); > @@ -202,7 +202,11 @@ xfs_end_io( > io_list))) { > list_del_init(&ioend->io_list); > iomap_ioend_try_merge(ioend, &tmp); > - xfs_end_ioend(ioend); > + if (bio_op(&ioend->io_bio) == REQ_OP_READ) > + iomap_finish_ioends(ioend, > + blk_status_to_errno(ioend->io_bio.bi_status)); > + else > + xfs_end_ioend_write(ioend); > cond_resched(); > } > } > diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c > index 7874cf745af3..f6cc63dcf961 100644 > --- a/fs/xfs/xfs_file.c > +++ b/fs/xfs/xfs_file.c > @@ -224,12 +224,34 @@ xfs_ilock_iocb_for_write( > return 0; > } > > +/* > + * Bounce buffering dio reads need a user context to copy back the data. > + * Use an ioend to provide that. > + */ > +static void > +xfs_dio_read_bounce_submit_io( > + const struct iomap_iter *iter, > + struct bio *bio, > + loff_t file_offset) > +{ > + iomap_init_ioend(iter->inode, bio, file_offset, IOMAP_IOEND_DIRECT); > + bio->bi_end_io = xfs_end_bio; > + submit_bio(bio); > +} > + > +static const struct iomap_dio_ops xfs_dio_read_bounce_ops = { > + .submit_io = xfs_dio_read_bounce_submit_io, > + .bio_set = &iomap_ioend_bioset, > +}; > + > STATIC ssize_t > xfs_file_dio_read( > struct kiocb *iocb, > struct iov_iter *to) > { > struct xfs_inode *ip = XFS_I(file_inode(iocb->ki_filp)); > + unsigned int dio_flags = 0; > + const struct iomap_dio_ops *dio_ops = NULL; > ssize_t ret; > > trace_xfs_file_direct_read(iocb, to); > @@ -242,7 +264,12 @@ xfs_file_dio_read( > ret = xfs_ilock_iocb(iocb, XFS_IOLOCK_SHARED); > if (ret) > return ret; > - ret = iomap_dio_rw(iocb, to, &xfs_read_iomap_ops, NULL, 0, NULL, 0); > + if (mapping_stable_writes(iocb->ki_filp->f_mapping)) { > + dio_ops = &xfs_dio_read_bounce_ops; > + dio_flags |= IOMAP_DIO_BOUNCE; > + } > + ret = iomap_dio_rw(iocb, to, &xfs_read_iomap_ops, dio_ops, dio_flags, > + NULL, 0); > xfs_iunlock(ip, XFS_IOLOCK_SHARED); > > return ret; > @@ -703,6 +730,8 @@ xfs_file_dio_write_aligned( > xfs_ilock_demote(ip, XFS_IOLOCK_EXCL); > iolock = XFS_IOLOCK_SHARED; > } > + if (mapping_stable_writes(iocb->ki_filp->f_mapping)) > + dio_flags |= IOMAP_DIO_BOUNCE; > trace_xfs_file_direct_write(iocb, from); > ret = iomap_dio_rw(iocb, from, ops, dops, dio_flags, ac, 0); > out_unlock: > @@ -750,6 +779,7 @@ xfs_file_dio_write_atomic( > { > unsigned int iolock = XFS_IOLOCK_SHARED; > ssize_t ret, ocount = iov_iter_count(from); > + unsigned int dio_flags = 0; > const struct iomap_ops *dops; > > /* > @@ -777,8 +807,10 @@ xfs_file_dio_write_atomic( > } > > trace_xfs_file_direct_write(iocb, from); > - ret = iomap_dio_rw(iocb, from, dops, &xfs_dio_write_ops, > - 0, NULL, 0); > + if (mapping_stable_writes(iocb->ki_filp->f_mapping)) > + dio_flags |= IOMAP_DIO_BOUNCE; > + ret = iomap_dio_rw(iocb, from, dops, &xfs_dio_write_ops, dio_flags, > + NULL, 0); > > /* > * The retry mechanism is based on the ->iomap_begin method returning > @@ -867,6 +899,9 @@ xfs_file_dio_write_unaligned( > if (flags & IOMAP_DIO_FORCE_WAIT) > inode_dio_wait(VFS_I(ip)); > > + if (mapping_stable_writes(iocb->ki_filp->f_mapping)) > + flags |= IOMAP_DIO_BOUNCE; > + > trace_xfs_file_direct_write(iocb, from); > ret = iomap_dio_rw(iocb, from, &xfs_direct_write_iomap_ops, > &xfs_dio_write_ops, flags, NULL, 0); > -- > 2.47.3 > >