From mboxrd@z Thu Jan 1 00:00:00 1970 From: Omar Sandoval Subject: Re: [PATCH v2] fideduperange.2: fix the discussion of maximum sizes Date: Tue, 22 Nov 2016 20:49:41 -0800 Message-ID: <20161123044941.GB27107@mew> References: <20161123044816.GG16807@birch.djwong.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <20161123044816.GG16807-PTl6brltDGh4DFYR7WNSRA@public.gmane.org> Sender: linux-api-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: "Darrick J. Wong" Cc: mtk.manpages-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org, linux-fsdevel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-api-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-xfs-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-btrfs-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-man-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: linux-api@vger.kernel.org On Tue, Nov 22, 2016 at 08:48:16PM -0800, Darrick J. Wong wrote: > 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 | 20 +++++++++++++++++--- > 1 file changed, 17 insertions(+), 3 deletions(-) > > diff --git a/man2/ioctl_fideduperange.2 b/man2/ioctl_fideduperange.2 > index 2112d10..057229d 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 +108,15 @@ 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. > +This limit will be enforced silently by the filesystem. > By convention, the storage used by > .IR src_fd > is mapped into > @@ -144,6 +151,13 @@ is set to indicate the error. > .SH ERRORS > Error codes can be one of, but are not limited to, the following: > .TP > +.B ENOMEM > +The kernel was unable to allocate sufficient memory to perform the > +operation or > +.IR dest_count > +is so large that the input argument description spans more than a single > +page of memory. > +.TP > .B EBADF > .IR src_fd > is not open for reading; Reviewed-by: Omar Sandoval -- Omar