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 BDC0135975; Tue, 15 Jul 2025 05:28:12 +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=1752557292; cv=none; b=AFg9m4sOcZYxrmQH/9sAKrbQcPfZbbwiqZQZgMR+ZU8xnAGKswDM8kJ+rXE5xZzaZP2Tlc5VAEI5DoxdMntdZtUhdEFf/zZS/42KLEA7RyFKIIlQrPnmwAIseVRD29RVDWCOOOiyKc8Z3vtYBwFSdnNp2KTFeI7S6l4FDrKXlI8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1752557292; c=relaxed/simple; bh=Fg4QHr5nbV2aZx8L9EV+fyurQsVPPodPUNC6K6KJdww=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=fsLC5r1o5DlXf+e3m+O/dV3NOHTsFdk+fGd99BO11wlGkmL1phoOX+YaKzUsNuAb4d4l57I7lC1L7n8oGBcjcJbqo47hMqe6xLaRqSsk5KGa/OMkQLcQ660EpoWL7Hb0IEkNdLZzDDQVDbXHYheLb9xVNJKOZAopY06RYc095UY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=iD8TyC3g; 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="iD8TyC3g" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5DDC4C4CEE3; Tue, 15 Jul 2025 05:28:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1752557292; bh=Fg4QHr5nbV2aZx8L9EV+fyurQsVPPodPUNC6K6KJdww=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=iD8TyC3gHnSdkmAy9IfybIXXI0dow7Pq8ChIFnatGKhnh/uzI26ZfpMiz+Ga9dRYo 6rDLSQb9lXESjWAg/nI7u0b+eddc1yI5EVAjEmqsjwuQZvYYaYTs9uOs97ggyAoiPd kjvXx+HAt0mX275WGu4XsUjZq50BZco/FoZqpy7pCbTxCBvs9iYh3KeEXZY0dGMcr3 Xe7sZkD5RmJpz9Q0yJBBw+TBRUt1Se2wj8WUt2+1uN8If7El01mjTq5YB6uXhnCiby o97ZgmgYiJMaDtPHPCrPEXTSZJqeexmGYKSwq+JSvo04riK0WcQuadp10+MjUQiZ/V sWQ7VEptyZFZw== Date: Mon, 14 Jul 2025 22:28:11 -0700 From: "Darrick J. Wong" To: Brian Foster Cc: linux-fsdevel@vger.kernel.org, linux-xfs@vger.kernel.org, linux-mm@kvack.org, hch@infradead.org, willy@infradead.org Subject: Re: [PATCH v3 5/7] xfs: fill dirty folios on zero range of unwritten mappings Message-ID: <20250715052811.GQ2672049@frogsfrogsfrogs> References: <20250714204122.349582-1-bfoster@redhat.com> <20250714204122.349582-6-bfoster@redhat.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: <20250714204122.349582-6-bfoster@redhat.com> On Mon, Jul 14, 2025 at 04:41:20PM -0400, Brian Foster wrote: > Use the iomap folio batch mechanism to select folios to zero on zero > range of unwritten mappings. Trim the resulting mapping if the batch > is filled (unlikely for current use cases) to distinguish between a > range to skip and one that requires another iteration due to a full > batch. > > Signed-off-by: Brian Foster > Reviewed-by: Christoph Hellwig > --- > fs/xfs/xfs_iomap.c | 23 +++++++++++++++++++++++ > 1 file changed, 23 insertions(+) > > diff --git a/fs/xfs/xfs_iomap.c b/fs/xfs/xfs_iomap.c > index b5cf5bc6308d..63054f7ead0e 100644 > --- a/fs/xfs/xfs_iomap.c > +++ b/fs/xfs/xfs_iomap.c > @@ -1691,6 +1691,8 @@ xfs_buffered_write_iomap_begin( > struct iomap *iomap, > struct iomap *srcmap) > { > + struct iomap_iter *iter = container_of(iomap, struct iomap_iter, > + iomap); > struct xfs_inode *ip = XFS_I(inode); > struct xfs_mount *mp = ip->i_mount; > xfs_fileoff_t offset_fsb = XFS_B_TO_FSBT(mp, offset); > @@ -1762,6 +1764,7 @@ xfs_buffered_write_iomap_begin( > */ > if (flags & IOMAP_ZERO) { > xfs_fileoff_t eof_fsb = XFS_B_TO_FSB(mp, XFS_ISIZE(ip)); > + u64 end; > > if (isnullstartblock(imap.br_startblock) && > offset_fsb >= eof_fsb) > @@ -1769,6 +1772,26 @@ xfs_buffered_write_iomap_begin( > if (offset_fsb < eof_fsb && end_fsb > eof_fsb) > end_fsb = eof_fsb; > > + /* > + * Look up dirty folios for unwritten mappings within EOF. > + * Providing this bypasses the flush iomap uses to trigger > + * extent conversion when unwritten mappings have dirty > + * pagecache in need of zeroing. > + * > + * Trim the mapping to the end pos of the lookup, which in turn > + * was trimmed to the end of the batch if it became full before > + * the end of the mapping. > + */ > + if (imap.br_state == XFS_EXT_UNWRITTEN && > + offset_fsb < eof_fsb) { > + loff_t len = min(count, > + XFS_FSB_TO_B(mp, imap.br_blockcount)); > + > + end = iomap_fill_dirty_folios(iter, offset, len); > + end_fsb = min_t(xfs_fileoff_t, end_fsb, > + XFS_B_TO_FSB(mp, end)); Hrmm. XFS_B_TO_FSB and not _FSBT? Can the rounding up behavior result in a missed byte range? I think the answer is no because @end should be aligned to a folio boundary, and folios can't be smaller than an fsblock. If the answer to the second question is indeed "no" then I think this is ok and Reviewed-by: "Darrick J. Wong" --D > + } > + > xfs_trim_extent(&imap, offset_fsb, end_fsb - offset_fsb); > } > > -- > 2.50.0 > >