From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (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 8D2891EE013; Thu, 13 Mar 2025 08:18:27 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.137.202.133 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741853909; cv=none; b=ELnfth9Bd0QmRezF6GZPHDJc4oVulhZ/dmEncpJGDATuY9TlfHlodnfC7sw+rQNOPAcRGj1PZpg8KTWPYpByMTGprlKzdv+tYPBxy8yalME8L7Blgiu7g80GzfuV8JLMrvKd55i3V2tKCzwq4I9kn6LN0T/kwIxgBCjKjhE6FoQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741853909; c=relaxed/simple; bh=g4/K6gaP0syt5iLZomYtePZjB7AKXL2MAAMEgNHrpDY=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=lGqrNRnNNmpbocqZXmVidLDHx1/HrPmyUX59ApyRwfbFtuRPk6aK9fCBonx3zDAB5Av0biRbPc74u/pN/5zjdpRw38LFnAQ8Qcz4Nm8hhFsfdVwfNr8zuzFEtTEXUlcstPzb3z+OWvn6+IVRn4ecoyvbxbHtua7FrxNjh/GZS1U= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org; spf=none smtp.mailfrom=bombadil.srs.infradead.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b=1Juq+lrw; arc=none smtp.client-ip=198.137.202.133 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=bombadil.srs.infradead.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="1Juq+lrw" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20210309; h=In-Reply-To:Content-Type:MIME-Version :References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=jrZs9WEq341HFyjMmgmQFBq+D9rAqTMpcEFhmRVau0E=; b=1Juq+lrw4oZNjLrixt7kwDDic8 NVzbIRyJRcEWLgJJgFS5G0UIgWSMXgPtr9k7FeWC3YDfWNYqG8N3K18nnN4GabV4lVqZT9YlQNxiW MOjts7PWj5gjckNu8RdmP8JPg5UIs+J684//tiZYUvKzIB9VtrFrpWJv/gdKsnnsj7e2/CqXxH5Cd Q7w4yvg+WnHKOb56+MaGreClDxvPp9kKEWpGb5sV1rQyegallky4pa7KcYHa6cVRAWjMD8nW4kOwj GK9CN8LH8kajoG6DHWtIbYKRvNeUSFohMTd3WchpG7WP8xh65TZxe5riQWpLcdxiXROVInAD3MR8H DAg8ztWg==; Received: from hch by bombadil.infradead.org with local (Exim 4.98 #2 (Red Hat Linux)) id 1tsdlq-0000000AWY3-3EZm; Thu, 13 Mar 2025 08:18:26 +0000 Date: Thu, 13 Mar 2025 01:18:26 -0700 From: Christoph Hellwig To: John Garry Cc: Christoph Hellwig , Dave Chinner , brauner@kernel.org, djwong@kernel.org, cem@kernel.org, linux-xfs@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, ojaswin@linux.ibm.com, ritesh.list@gmail.com, martin.petersen@oracle.com Subject: Re: [PATCH RFC v5 10/10] iomap: Rename ATOMIC flags again Message-ID: References: <20250310183946.932054-1-john.g.garry@oracle.com> <20250310183946.932054-11-john.g.garry@oracle.com> <85074165-4e56-421d-970b-0963da8de0e2@oracle.com> <3aeb1d0e-6c74-4bfe-914d-22ba4152bc7f@oracle.com> <157f42f1-1bad-4320-b708-2397ab773e34@oracle.com> Precedence: bulk X-Mailing-List: linux-xfs@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: X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html Something like this (untestested): diff --git a/fs/iomap/direct-io.c b/fs/iomap/direct-io.c index 5299f70428ef..3fa21445906a 100644 --- a/fs/iomap/direct-io.c +++ b/fs/iomap/direct-io.c @@ -312,27 +312,20 @@ static int iomap_dio_zero(const struct iomap_iter *iter, struct iomap_dio *dio, } /* - * Figure out the bio's operation flags from the dio request, the - * mapping, and whether or not we want FUA. Note that we can end up - * clearing the WRITE_THROUGH flag in the dio request. + * Use a FUA write if we need datasync semantics and this is a pure data I/O + * that doesn't require any metadata updates (including after I/O completion + * such as unwritten extent conversion) and the underlying device either + * doesn't have a volatile write cache or supports FUA. + * This allows us to avoid cache flushes on I/O completion. */ -static inline blk_opf_t iomap_dio_bio_opflags(struct iomap_dio *dio, - const struct iomap *iomap, bool use_fua, bool atomic_hw) +static inline bool iomap_dio_can_use_fua(const struct iomap *iomap, + struct iomap_dio *dio) { - blk_opf_t opflags = REQ_SYNC | REQ_IDLE; - - if (!(dio->flags & IOMAP_DIO_WRITE)) - return REQ_OP_READ; - - opflags |= REQ_OP_WRITE; - if (use_fua) - opflags |= REQ_FUA; - else - dio->flags &= ~IOMAP_DIO_WRITE_THROUGH; - if (atomic_hw) - opflags |= REQ_ATOMIC; - - return opflags; + if (iomap->flags & (IOMAP_F_SHARED | IOMAP_F_DIRTY)) + return false; + if (!(dio->flags & IOMAP_DIO_WRITE_THROUGH)) + return false; + return !bdev_write_cache(iomap->bdev) || bdev_fua(iomap->bdev); } static int iomap_dio_bio_iter(struct iomap_iter *iter, struct iomap_dio *dio) @@ -343,49 +336,53 @@ static int iomap_dio_bio_iter(struct iomap_iter *iter, struct iomap_dio *dio) bool atomic_hw = iter->flags & IOMAP_ATOMIC_HW; const loff_t length = iomap_length(iter); loff_t pos = iter->pos; - blk_opf_t bio_opf; + blk_opf_t bio_opf = REQ_SYNC | REQ_IDLE; struct bio *bio; bool need_zeroout = false; - bool use_fua = false; int nr_pages, ret = 0; u64 copied = 0; size_t orig_count; - if (atomic_hw && length != iter->len) - return -EINVAL; - if ((pos | length) & (bdev_logical_block_size(iomap->bdev) - 1) || !bdev_iter_is_aligned(iomap->bdev, dio->submit.iter)) return -EINVAL; - if (iomap->type == IOMAP_UNWRITTEN) { - dio->flags |= IOMAP_DIO_UNWRITTEN; - need_zeroout = true; - } + if (dio->flags & IOMAP_DIO_WRITE) { + bio_opf |= REQ_OP_WRITE; + + if (atomic_hw) { + if (length != iter->len) + return -EINVAL; + bio_opf |= REQ_ATOMIC; + } - if (iomap->flags & IOMAP_F_SHARED) - dio->flags |= IOMAP_DIO_COW; + if (iomap->type == IOMAP_UNWRITTEN) { + dio->flags |= IOMAP_DIO_UNWRITTEN; + need_zeroout = true; + } - if (iomap->flags & IOMAP_F_NEW) { - need_zeroout = true; - } else if (iomap->type == IOMAP_MAPPED) { - /* - * Use a FUA write if we need datasync semantics, this is a pure - * data IO that doesn't require any metadata updates (including - * after IO completion such as unwritten extent conversion) and - * the underlying device either supports FUA or doesn't have - * a volatile write cache. This allows us to avoid cache flushes - * on IO completion. If we can't use writethrough and need to - * sync, disable in-task completions as dio completion will - * need to call generic_write_sync() which will do a blocking - * fsync / cache flush call. - */ - if (!(iomap->flags & (IOMAP_F_SHARED|IOMAP_F_DIRTY)) && - (dio->flags & IOMAP_DIO_WRITE_THROUGH) && - (bdev_fua(iomap->bdev) || !bdev_write_cache(iomap->bdev))) - use_fua = true; - else if (dio->flags & IOMAP_DIO_NEED_SYNC) - dio->flags &= ~IOMAP_DIO_CALLER_COMP; + if (iomap->flags & IOMAP_F_SHARED) + dio->flags |= IOMAP_DIO_COW; + + if (iomap->flags & IOMAP_F_NEW) { + need_zeroout = true; + } else if (iomap->type == IOMAP_MAPPED) { + if (iomap_dio_can_use_fua(iomap, dio)) { + bio_opf |= REQ_FUA; + } else { + dio->flags &= ~IOMAP_DIO_WRITE_THROUGH; + /* + * Disable in-task completions if we can't use + * writethrough and need to sync as the I/O + * completion handler has to force a (blocking) + * cache flush. + */ + if (dio->flags & IOMAP_DIO_NEED_SYNC) + dio->flags &= ~IOMAP_DIO_CALLER_COMP; + } + } + } else { + bio_opf |= REQ_OP_READ; } /* @@ -407,7 +404,7 @@ static int iomap_dio_bio_iter(struct iomap_iter *iter, struct iomap_dio *dio) * during completion processing. */ if (need_zeroout || - ((dio->flags & IOMAP_DIO_NEED_SYNC) && !use_fua) || + ((dio->flags & IOMAP_DIO_NEED_SYNC) && !(bio_opf & REQ_FUA)) || ((dio->flags & IOMAP_DIO_WRITE) && pos >= i_size_read(inode))) dio->flags &= ~IOMAP_DIO_CALLER_COMP; @@ -428,8 +425,6 @@ static int iomap_dio_bio_iter(struct iomap_iter *iter, struct iomap_dio *dio) goto out; } - bio_opf = iomap_dio_bio_opflags(dio, iomap, use_fua, atomic_hw); - nr_pages = bio_iov_vecs_to_alloc(dio->submit.iter, BIO_MAX_VECS); do { size_t n;