From: Trond Myklebust <trondmy@hammerspace.com>
To: "chucklever@gmail.com" <chucklever@gmail.com>
Cc: "linux-nfs@vger.kernel.org" <linux-nfs@vger.kernel.org>
Subject: Re: [PATCH 15/16] nfsd: Fixes for nfsd4_encode_read_plus_data()
Date: Wed, 9 Dec 2020 17:01:03 +0000 [thread overview]
Message-ID: <2f9659232d159e2992960ec5000bca4275412fe2.camel@hammerspace.com> (raw)
In-Reply-To: <DF972250-F1EA-4996-8CEB-18171BD346C2@gmail.com>
On Wed, 2020-12-09 at 11:57 -0500, Chuck Lever wrote:
>
>
> > On Dec 9, 2020, at 11:39 AM, Trond Myklebust <
> > trondmy@hammerspace.com> wrote:
> >
> > On Wed, 2020-12-09 at 11:16 -0500, Chuck Lever wrote:
> > > Hey-
> > >
> > > > On Dec 9, 2020, at 9:48 AM, trondmy@kernel.org wrote:
> > > >
> > > > From: Trond Myklebust <trond.myklebust@hammerspace.com>
> > > >
> > > > Ensure that we encode the data payload + padding, and that we
> > > > truncate
> > > > the preallocated buffer to the actual read size.
> > >
> > > Did you intend to merge 15/16 and 16/16 through your tree?
> >
> > No. They can go through the nfsd tree. I included them here because
> > they are necessary in order to pass the xfstests.
>
> Would it be OK if they went in 5.11-rc? I've got the initial
> merge tag prepared already. If they can't wait, let me know.
I'm fine with that.
>
>
> > > Can the patch descriptions say a little more about why these
> > > changes are necessary? If they fix a misbehavior, describe
> > > the problem.
> >
> > It's the same problem and solution that exists in the READ code.
> >
> > nfsd_readv() doesn't necessarily return the same number of bytes
> > that
> > we requested and preallocated buffer space for. So to deal with
> > that,
> > we have to truncate the preallocated buffer.
>
> Huh. I thought it was doing that already? Oh, that's just for
> the cases where the server returns an error status. The
> READ_PLUS encoder incorrectly does not do that truncation for
> short READs... got it.
>
>
> > Finally, we have to write zeros into the padding bytes after the
> > read
> > buffer.
>
> Right. Then the problem statement is that the server's READ_PLUS
> XDR encoder isn't padding the read buffer properly.
>
> Quibble: perhaps these are two separate issues that each deserve
> their own patches with Fixes: tags (and if you re-post these,
> please add a Fixes: tag to 16/16 too).
I'm not planning on reposting.
--
Trond Myklebust
Linux NFS client maintainer, Hammerspace
trond.myklebust@hammerspace.com
prev parent reply other threads:[~2020-12-09 17:01 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-09 14:47 [PATCH 00/16] Fixes for the NFSv4.2 READ_PLUS operation trondmy
2020-12-09 14:47 ` [PATCH 01/16] SUNRPC: _shift_data_left/right_pages should check the shift length trondmy
2020-12-09 14:47 ` [PATCH 02/16] SUNRPC: Fixes for xdr_align_data() trondmy
2020-12-09 14:47 ` [PATCH 03/16] SUNRPC: Fix xdr_expand_hole() trondmy
2020-12-09 14:47 ` [PATCH 04/16] SUNRPC: Cleanup xdr_shrink_bufhead() trondmy
2020-12-09 14:47 ` [PATCH 05/16] SUNRPC: _copy_to/from_pages() now check for zero length trondmy
2020-12-09 14:47 ` [PATCH 06/16] SUNRPC: Clean up open coded setting of the xdr_stream 'nwords' field trondmy
2020-12-09 14:47 ` [PATCH 07/16] SUNRPC: Cleanup - constify a number of xdr_buf helpers trondmy
2020-12-09 14:47 ` [PATCH 08/16] SUNRPC: Avoid unnecessary copies in xdr_buf_pages_copy_left/right() trondmy
2020-12-09 14:47 ` [PATCH 09/16] NFSv4.2: Ensure we always reset the result->count in decode_read_plus() trondmy
2020-12-09 14:47 ` [PATCH 10/16] NFSv4.2: decode_read_plus_data() must skip padding after data segment trondmy
2020-12-09 14:47 ` [PATCH 11/16] NFSv4.2: decode_read_plus_hole() needs to check the extent offset trondmy
2020-12-09 14:47 ` [PATCH 12/16] NFSv4.2: Handle hole lengths that exceed the READ_PLUS read buffer trondmy
2020-12-09 14:47 ` [PATCH 13/16] NFSv4.2: Don't error when exiting early on a READ_PLUS buffer overflow trondmy
2020-12-09 14:47 ` [PATCH 14/16] NFSv4.2: Deal with potential READ_PLUS data extent " trondmy
2020-12-09 14:48 ` [PATCH 15/16] nfsd: Fixes for nfsd4_encode_read_plus_data() trondmy
2020-12-09 14:48 ` [PATCH 16/16] nfsd: Don't set eof on a truncated READ_PLUS trondmy
2020-12-09 16:16 ` [PATCH 15/16] nfsd: Fixes for nfsd4_encode_read_plus_data() Chuck Lever
2020-12-09 16:39 ` Trond Myklebust
2020-12-09 16:57 ` Chuck Lever
2020-12-09 17:01 ` Trond Myklebust [this message]
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