On Thu, 2020-12-03 at 17:47 +0000, Frank van der Linden wrote:
> On Thu, Dec 03, 2020 at 05:13:26PM +0000, Trond Myklebust wrote:
> [...]
> > You probably need this one in addition to the first patch.
> > 8<----------------------------------------------------
> > From fec77469f373fbccb292c2d522f2ebee3b9011a8 Mon Sep 17 00:00:00
> > 2001
> > From: Trond Myklebust <trond.myklebust@xxxxxxxxxxxxxxx>
> > Date: Thu, 3 Dec 2020 12:04:51 -0500
> > Subject: [PATCH] NFSv4.2: Fix up the get/listxattr calls to
> > rpc_prepare_reply_pages()
> >
> > Ensure that both getxattr and listxattr page array are correctly
> > aligned, and that getxattr correctly accounts for the page padding
> > word.
> >
> > Signed-off-by: Trond Myklebust <trond.myklebust@xxxxxxxxxxxxxxx>
> > ---
> > fs/nfs/nfs42xdr.c | 12 +++++++-----
> > 1 file changed, 7 insertions(+), 5 deletions(-)
> >
> > diff --git a/fs/nfs/nfs42xdr.c b/fs/nfs/nfs42xdr.c
> > index 8432bd6b95f0..103978ff76c9 100644
> > --- a/fs/nfs/nfs42xdr.c
> > +++ b/fs/nfs/nfs42xdr.c
> > @@ -191,7 +191,7 @@
> >
> > #define encode_getxattr_maxsz (op_encode_hdr_maxsz + 1 + \
> > nfs4_xattr_name_maxsz)
> > -#define decode_getxattr_maxsz (op_decode_hdr_maxsz + 1 + 1)
> > +#define decode_getxattr_maxsz (op_decode_hdr_maxsz + 1 +
> > pagepad_maxsz)
> > #define encode_setxattr_maxsz (op_encode_hdr_maxsz + \
> > 1 + nfs4_xattr_name_maxsz + 1)
> > #define decode_setxattr_maxsz (op_decode_hdr_maxsz +
> > decode_change_info_maxsz)
> > @@ -1476,17 +1476,18 @@ static void nfs4_xdr_enc_getxattr(struct
> > rpc_rqst *req, struct xdr_stream *xdr,
> > struct compound_hdr hdr = {
> > .minorversion = nfs4_xdr_minorversion(&args-
> > > seq_args),
> > };
> > + uint32_t replen;
> > size_t plen;
> >
> > encode_compound_hdr(xdr, req, &hdr);
> > encode_sequence(xdr, &args->seq_args, &hdr);
> > encode_putfh(xdr, args->fh, &hdr);
> > + replen = hdr.replen + op_decode_hdr_maxsz + 1;
> > encode_getxattr(xdr, args->xattr_name, &hdr);
> >
> > plen = args->xattr_len ? args->xattr_len : XATTR_SIZE_MAX;
> >
> > - rpc_prepare_reply_pages(req, args->xattr_pages, 0, plen,
> > - hdr.replen);
> > + rpc_prepare_reply_pages(req, args->xattr_pages, 0, plen,
> > replen);
> > req->rq_rcv_buf.flags |= XDRBUF_SPARSE_PAGES;
> >
> > encode_nops(&hdr);
> > @@ -1520,14 +1521,15 @@ static void nfs4_xdr_enc_listxattrs(struct
> > rpc_rqst *req,
> > struct compound_hdr hdr = {
> > .minorversion = nfs4_xdr_minorversion(&args-
> > > seq_args),
> > };
> > + uint32_t replen;
> >
> > encode_compound_hdr(xdr, req, &hdr);
> > encode_sequence(xdr, &args->seq_args, &hdr);
> > encode_putfh(xdr, args->fh, &hdr);
> > + replen = hdr.replen + op_decode_hdr_maxsz + 2 + 1;
> > encode_listxattrs(xdr, args, &hdr);
> >
> > - rpc_prepare_reply_pages(req, args->xattr_pages, 0, args-
> > > count,
> > - hdr.replen);
> > + rpc_prepare_reply_pages(req, args->xattr_pages, 0, args-
> > > count, replen);
> >
> > encode_nops(&hdr);
> > }
> > --
> > 2.28.0
>
> Hm.. that doesn't seem to match other, similar functionality.
> Why is the additional padding and op_decode_hdr_maxsz needed?
>
It isn't extra padding. It is the same padding, but after the cleanup
that removes the confusing behaviour of rpc_prepare_reply_pages(), the
caller is supposed to supply the actual offset for the beginning of the
page data instead of adding the padding to that offset:
https://git.linux-nfs.org/?p=trondmy/linux-nfs.git;a=commitdiff;h=9ed5af268e88f6e5b65376be98d652b37cb20d7b
--
Trond Myklebust
Linux NFS client maintainer, Hammerspace
trond.myklebust@xxxxxxxxxxxxxxx
