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 <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
diff --git a/fs/nfsd/nfsxdr.c b/fs/nfsd/nfsxdr.c
index db24ae8..a43e826 100644
--- a/fs/nfsd/nfsxdr.c
+++ b/fs/nfsd/nfsxdr.c
@@ -71,22 +71,6 @@ decode_filename(__be32 *p, char **namp, unsigned int *lenp)
}
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)
{
u32 tmp, tmp1;
@@ -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