From 38a70315599dedacd9ff3bd1016f9048c9d0ad12 Mon Sep 17 00:00:00 2001 From: Chuck Lever Date: Tue, 27 Mar 2018 10:54:21 -0400 Subject: NFSD: Clean up legacy NFS SYMLINK argument XDR decoders Move common code in NFSD's legacy SYMLINK decoders into a helper. The immediate benefits include: - one fewer data copies on transports that support DDP - consistent error checking across all versions - reduction of code duplication - support for both legal forms of SYMLINK requests on RDMA transports for all versions of NFS (in particular, NFSv2, for completeness) In the long term, this helper is an appropriate spot to perform a per-transport call-out to fill the pathname argument using, say, RDMA Reads. Filling the pathname in the proc function also means that eventually the incoming filehandle can be interpreted so that filesystem- specific memory can be allocated as a sink for the pathname argument, rather than using anonymous pages. Signed-off-by: Chuck Lever Signed-off-by: J. Bruce Fields --- fs/nfsd/nfsxdr.c | 49 +++++++++++++++++++++++++++++-------------------- 1 file changed, 29 insertions(+), 20 deletions(-) (limited to 'fs/nfsd/nfsxdr.c') diff --git a/fs/nfsd/nfsxdr.c b/fs/nfsd/nfsxdr.c index db24ae8b67e0..a43e8260520a 100644 --- a/fs/nfsd/nfsxdr.c +++ b/fs/nfsd/nfsxdr.c @@ -70,22 +70,6 @@ decode_filename(__be32 *p, char **namp, unsigned int *lenp) return p; } -static __be32 * -decode_pathname(__be32 *p, char **namp, unsigned int *lenp) -{ - char *name; - unsigned int i; - - if ((p = xdr_decode_string_inplace(p, namp, lenp, NFS_MAXPATHLEN)) != NULL) { - for (i = 0, name = *namp; i < *lenp; i++, name++) { - if (*name == '\0') - return NULL; - } - } - - return p; -} - static __be32 * decode_sattr(__be32 *p, struct iattr *iap) { @@ -384,14 +368,39 @@ int nfssvc_decode_symlinkargs(struct svc_rqst *rqstp, __be32 *p) { struct nfsd_symlinkargs *args = rqstp->rq_argp; + char *base = (char *)p; + size_t xdrlen; if ( !(p = decode_fh(p, &args->ffh)) - || !(p = decode_filename(p, &args->fname, &args->flen)) - || !(p = decode_pathname(p, &args->tname, &args->tlen))) + || !(p = decode_filename(p, &args->fname, &args->flen))) return 0; - p = decode_sattr(p, &args->attrs); - return xdr_argsize_check(rqstp, p); + args->tlen = ntohl(*p++); + if (args->tlen == 0) + return 0; + + args->first.iov_base = p; + args->first.iov_len = rqstp->rq_arg.head[0].iov_len; + args->first.iov_len -= (char *)p - base; + + /* This request is never larger than a page. Therefore, + * transport will deliver either: + * 1. pathname in the pagelist -> sattr is in the tail. + * 2. everything in the head buffer -> sattr is in the head. + */ + if (rqstp->rq_arg.page_len) { + if (args->tlen != rqstp->rq_arg.page_len) + return 0; + p = rqstp->rq_arg.tail[0].iov_base; + } else { + xdrlen = XDR_QUADLEN(args->tlen); + if (xdrlen > args->first.iov_len - (8 * sizeof(__be32))) + return 0; + p += xdrlen; + } + decode_sattr(p, &args->attrs); + + return 1; } int -- cgit v1.2.3