From eae03e2ac80a3476f0652cb0ee451d7b06d30564 Mon Sep 17 00:00:00 2001 From: Chuck Lever Date: Fri, 18 Aug 2017 11:12:27 -0400 Subject: [PATCH] nfsd: Incoming xdr_bufs may have content in tail buffer Since the beginning, svcsock has built a received RPC Call message by populating the xdr_buf's head, then placing the remaining message bytes in the xdr_buf's page list. The xdr_buf's tail is never populated. This means that an NFSv4 COMPOUND containing an NFS WRITE operation plus trailing operations has a page list that contains the WRITE data payload followed by the trailing operations. NFSv4 XDR decoders will not look in the xdr_buf's tail, ever, because svcsock never put anything there. To support transports that can pass the write payload in the xdr_buf's pagelist and trailing content in the xdr_buf's tail, introduce logic in READ_BUF that switches to the xdr_buf's tail vec when the decoder runs out of content in rq_arg.pages. Signed-off-by: Chuck Lever Signed-off-by: J. Bruce Fields --- fs/nfsd/nfs4xdr.c | 20 ++++++++++++++++++++ fs/nfsd/xdr4.h | 1 + 2 files changed, 21 insertions(+) diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c index 08691fe394b2..2c61c6b8ae09 100644 --- a/fs/nfsd/nfs4xdr.c +++ b/fs/nfsd/nfs4xdr.c @@ -159,6 +159,25 @@ static __be32 *read_buf(struct nfsd4_compoundargs *argp, u32 nbytes) */ unsigned int avail = (char *)argp->end - (char *)argp->p; __be32 *p; + + if (argp->pagelen == 0) { + struct kvec *vec = &argp->rqstp->rq_arg.tail[0]; + + if (!argp->tail) { + argp->tail = true; + avail = vec->iov_len; + argp->p = vec->iov_base; + argp->end = vec->iov_base + avail; + } + + if (avail < nbytes) + return NULL; + + p = argp->p; + argp->p += XDR_QUADLEN(nbytes); + return p; + } + if (avail + argp->pagelen < nbytes) return NULL; if (avail + PAGE_SIZE < nbytes) /* need more than a page !! */ @@ -4471,6 +4490,7 @@ nfs4svc_decode_compoundargs(struct svc_rqst *rqstp, __be32 *p) args->end = rqstp->rq_arg.head[0].iov_base + rqstp->rq_arg.head[0].iov_len; args->pagelist = rqstp->rq_arg.pages; args->pagelen = rqstp->rq_arg.page_len; + args->tail = false; args->tmpp = NULL; args->to_free = NULL; args->ops = args->iops; diff --git a/fs/nfsd/xdr4.h b/fs/nfsd/xdr4.h index f8a0b6549a88..1e4edbf70052 100644 --- a/fs/nfsd/xdr4.h +++ b/fs/nfsd/xdr4.h @@ -615,6 +615,7 @@ struct nfsd4_compoundargs { __be32 * end; struct page ** pagelist; int pagelen; + bool tail; __be32 tmp[8]; __be32 * tmpp; struct svcxdr_tmpbuf *to_free;