From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from userp1040.oracle.com ([156.151.31.81]:39032 "EHLO userp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755798AbcKWEW3 (ORCPT ); Tue, 22 Nov 2016 23:22:29 -0500 Date: Tue, 22 Nov 2016 20:22:22 -0800 From: "Darrick J. Wong" To: mtk.manpages@gmail.com Cc: linux-fsdevel@vger.kernel.org, linux-api@vger.kernel.org, linux-xfs@vger.kernel.org, linux-btrfs@vger.kernel.org, linux-man@vger.kernel.org Subject: [PATCH] fideduperange.2: fix the discussion of maximum sizes Message-ID: <20161123042222.GA30324@birch.djwong.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: linux-btrfs-owner@vger.kernel.org List-ID: Fix the discussion of the limitations on the dest_count and src_length parameters to the fideduperange ioctl to reflect what's actually in the kernel. Signed-off-by: Darrick J. Wong --- man2/ioctl_fideduperange.2 | 12 +++++++++--- 1 file changed, 9 insertions(+), 3 deletions(-) diff --git a/man2/ioctl_fideduperange.2 b/man2/ioctl_fideduperange.2 index 2112d10..59f0ea9 100644 --- a/man2/ioctl_fideduperange.2 +++ b/man2/ioctl_fideduperange.2 @@ -95,7 +95,7 @@ struct file_dedupe_range_info { .in Each deduplication operation targets -.IR length +.IR src_length bytes in file descriptor .IR dest_fd at offset @@ -108,8 +108,14 @@ During the call, must be open for reading and .IR dest_fd must be open for writing. -For any call to this ioctl, there may not be more than 65,536 -requests attached; each request may not exceed 16MiB. +The combined size of the struct +.IR file_dedupe_range +and the struct +.IR file_dedupe_range_info +array must not exceed the system page size. +The maximum size of +.IR src_length +is filesystem dependent and is typically 16MiB. By convention, the storage used by .IR src_fd is mapped into