nfsd4: use xdr_truncate_encode

Now that lengths are reliable, we can use xdr_truncate instead of
open-coding it everywhere.

Signed-off-by: J. Bruce Fields <bfields@redhat.com>

1 files changed, 16 insertions, 20 deletions

diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c
index 57f60810b745..c2815f4849bf 100644
--- a/fs/nfsd/nfs4xdr.c
+++ b/fs/nfsd/nfs4xdr.c
@@ -2053,7 +2053,7 @@ nfsd4_encode_fattr(struct xdr_stream *xdr, struct svc_fh *fhp,
         struct svc_fh *tempfh = NULL;
         struct kstatfs statfs;
         __be32 *p;
-        __be32 *start = xdr->p;
+        int starting_len = xdr->buf->len;
         __be32 *attrlenp;
         u32 dummy;
         u64 dummy64;
@@ -2547,13 +2547,8 @@ out:
                 fh_put(tempfh);
                 kfree(tempfh);
         }
-        if (status) {
-                int nbytes = (char *)xdr->p - (char *)start;
-                /* open code what *should* be xdr_truncate(xdr, len); */
-                xdr->iov->iov_len -= nbytes;
-                xdr->buf->len -= nbytes;
-                xdr->p = start;
-        }
+        if (status)
+                xdr_truncate_encode(xdr, starting_len);
         return status;
 out_nfserr:
         status = nfserrno(err);
@@ -3008,6 +3003,7 @@ nfsd4_encode_read(struct nfsd4_compoundres *resp, __be32 nfserr,
         struct page *page;
         unsigned long maxcount; 
         struct xdr_stream *xdr = &resp->xdr;
+        int starting_len = xdr->buf->len;
         long len;
         __be32 *p;
 
@@ -3044,9 +3040,13 @@ nfsd4_encode_read(struct nfsd4_compoundres *resp, __be32 nfserr,
                         &maxcount);
 
         if (nfserr) {
-                xdr->p -= 2;
-                xdr->iov->iov_len -= 8;
-                xdr->buf->len -= 8;
+                /*
+                 * nfsd_splice_actor may have already messed with the
+                 * page length; reset it so as not to confuse
+                 * xdr_truncate_encode:
+                 */
+                xdr->buf->page_len = 0;
+                xdr_truncate_encode(xdr, starting_len);
                 return nfserr;
         }
         eof = (read->rd_offset + maxcount >=
@@ -3079,6 +3079,7 @@ nfsd4_encode_readlink(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd
         int maxcount;
         struct xdr_stream *xdr = &resp->xdr;
         char *page;
+        int length_offset = xdr->buf->len;
         __be32 *p;
 
         if (nfserr)
@@ -3103,9 +3104,7 @@ nfsd4_encode_readlink(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd
         if (nfserr == nfserr_isdir)
                 nfserr = nfserr_inval;
         if (nfserr) {
-                xdr->p--;
-                xdr->iov->iov_len -= 4;
-                xdr->buf->len -= 4;
+                xdr_truncate_encode(xdr, length_offset);
                 return nfserr;
         }
 
@@ -3134,7 +3133,8 @@ nfsd4_encode_readdir(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4
         int maxcount;
         loff_t offset;
         struct xdr_stream *xdr = &resp->xdr;
-        __be32 *page, *savep, *tailbase;
+        int starting_len = xdr->buf->len;
+        __be32 *page, *tailbase;
         __be32 *p;
 
         if (nfserr)
@@ -3145,7 +3145,6 @@ nfsd4_encode_readdir(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4
                 return nfserr_resource;
 
         RESERVE_SPACE(NFS4_VERIFIER_SIZE);
-        savep = p;
 
         /* XXX: Following NFSv3, we ignore the READDIR verifier for now. */
         WRITE32(0);
@@ -3207,10 +3206,7 @@ nfsd4_encode_readdir(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4
 
         return 0;
 err_no_verf:
-        xdr->p = savep;
-        xdr->iov->iov_len = ((char *)resp->xdr.p)
-                                - (char *)resp->xdr.buf->head[0].iov_base;
-        xdr->buf->len = xdr->iov->iov_len;
+        xdr_truncate_encode(xdr, starting_len);
         return nfserr;
 }