NFSD: Update the NFSv2 READDIR entry encoder to use struct xdr_stream

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

diff --git a/fs/nfsd/nfsproc.c b/fs/nfsd/nfsproc.c
index 1acff9f..86d438f 100644 (file)
--- a/fs/nfsd/nfsproc.c
+++ b/fs/nfsd/nfsproc.c
@@ -559,14 +559,27 @@ static void nfsd_init_dirlist_pages(struct svc_rqst *rqstp,
                                    struct nfsd_readdirres *resp,
                                    int count)
 {
+       struct xdr_buf *buf = &resp->dirlist;
+       struct xdr_stream *xdr = &resp->xdr;
+
        count = min_t(u32, count, PAGE_SIZE);
 
-       /* Convert byte count to number of words (i.e. >> 2),
-        * and reserve room for the NULL ptr & eof flag (-2 words) */
-       resp->buflen = (count >> 2) - 2;
+       memset(buf, 0, sizeof(*buf));
 
-       resp->buffer = page_address(*rqstp->rq_next_page);
+       /* Reserve room for the NULL ptr & eof flag (-2 words) */
+       buf->buflen = count - sizeof(__be32) * 2;
+       buf->pages = rqstp->rq_next_page;
        rqstp->rq_next_page++;
+
+       /* This is xdr_init_encode(), but it assumes that
+        * the head kvec has already been consumed. */
+       xdr_set_scratch_buffer(xdr, NULL, 0);
+       xdr->buf = buf;
+       xdr->page_ptr = buf->pages;
+       xdr->iov = NULL;
+       xdr->p = page_address(*buf->pages);
+       xdr->end = xdr->p + (PAGE_SIZE >> 2);
+       xdr->rqst = NULL;
 }
 
 /*
@@ -585,12 +598,11 @@ nfsd_proc_readdir(struct svc_rqst *rqstp)
 
        nfsd_init_dirlist_pages(rqstp, resp, argp->count);
 
-       resp->offset = NULL;
        resp->common.err = nfs_ok;
-       /* Read directory and encode entries on the fly */
+       resp->cookie_offset = 0;
        offset = argp->cookie;
        resp->status = nfsd_readdir(rqstp, &argp->fh, &offset,
-                                   &resp->common, nfssvc_encode_entry);
+                                   &resp->common, nfs2svc_encode_entry);
        nfssvc_encode_nfscookie(resp, offset);
 
        fh_put(&argp->fh);

diff --git a/fs/nfsd/nfsxdr.c b/fs/nfsd/nfsxdr.c
index 9522e5c..1102d40 100644 (file)
--- a/fs/nfsd/nfsxdr.c
+++ b/fs/nfsd/nfsxdr.c
@@ -576,12 +576,13 @@ nfssvc_encode_readdirres(struct svc_rqst *rqstp, __be32 *p)
 {
        struct xdr_stream *xdr = &rqstp->rq_res_stream;
        struct nfsd_readdirres *resp = rqstp->rq_resp;
+       struct xdr_buf *dirlist = &resp->dirlist;
 
        if (!svcxdr_encode_stat(xdr, resp->status))
                return 0;
        switch (resp->status) {
        case nfs_ok:
-               xdr_write_pages(xdr, &resp->page, 0, resp->count << 2);
+               xdr_write_pages(xdr, dirlist->pages, 0, dirlist->len);
                /* no more entries */
                if (xdr_stream_encode_item_absent(xdr) < 0)
                        return 0;
@@ -623,14 +624,86 @@ nfssvc_encode_statfsres(struct svc_rqst *rqstp, __be32 *p)
  * @resp: readdir result context
  * @offset: offset cookie to encode
  *
+ * The buffer space for the offset cookie has already been reserved
+ * by svcxdr_encode_entry_common().
  */
 void nfssvc_encode_nfscookie(struct nfsd_readdirres *resp, u32 offset)
 {
-       if (!resp->offset)
+       __be32 cookie = cpu_to_be32(offset);
+
+       if (!resp->cookie_offset)
                return;
 
-       *resp->offset = cpu_to_be32(offset);
-       resp->offset = NULL;
+       write_bytes_to_xdr_buf(&resp->dirlist, resp->cookie_offset, &cookie,
+                              sizeof(cookie));
+       resp->cookie_offset = 0;
+}
+
+static bool
+svcxdr_encode_entry_common(struct nfsd_readdirres *resp, const char *name,
+                          int namlen, loff_t offset, u64 ino)
+{
+       struct xdr_buf *dirlist = &resp->dirlist;
+       struct xdr_stream *xdr = &resp->xdr;
+
+       if (xdr_stream_encode_item_present(xdr) < 0)
+               return false;
+       /* fileid */
+       if (xdr_stream_encode_u32(xdr, (u32)ino) < 0)
+               return false;
+       /* name */
+       if (xdr_stream_encode_opaque(xdr, name, min(namlen, NFS2_MAXNAMLEN)) < 0)
+               return false;
+       /* cookie */
+       resp->cookie_offset = dirlist->len;
+       if (xdr_stream_encode_u32(xdr, ~0U) < 0)
+               return false;
+
+       return true;
+}
+
+/**
+ * nfs2svc_encode_entry - encode one NFSv2 READDIR entry
+ * @data: directory context
+ * @name: name of the object to be encoded
+ * @namlen: length of that name, in bytes
+ * @offset: the offset of the previous entry
+ * @ino: the fileid of this entry
+ * @d_type: unused
+ *
+ * Return values:
+ *   %0: Entry was successfully encoded.
+ *   %-EINVAL: An encoding problem occured, secondary status code in resp->common.err
+ *
+ * On exit, the following fields are updated:
+ *   - resp->xdr
+ *   - resp->common.err
+ *   - resp->cookie_offset
+ */
+int nfs2svc_encode_entry(void *data, const char *name, int namlen,
+                        loff_t offset, u64 ino, unsigned int d_type)
+{
+       struct readdir_cd *ccd = data;
+       struct nfsd_readdirres *resp = container_of(ccd,
+                                                   struct nfsd_readdirres,
+                                                   common);
+       unsigned int starting_length = resp->dirlist.len;
+
+       /* The offset cookie for the previous entry */
+       nfssvc_encode_nfscookie(resp, offset);
+
+       if (!svcxdr_encode_entry_common(resp, name, namlen, offset, ino))
+               goto out_toosmall;
+
+       xdr_commit_encode(&resp->xdr);
+       resp->common.err = nfs_ok;
+       return 0;
+
+out_toosmall:
+       resp->cookie_offset = 0;
+       resp->common.err = nfserr_toosmall;
+       resp->dirlist.len = starting_length;
+       return -EINVAL;
 }
 
 int

diff --git a/fs/nfsd/xdr.h b/fs/nfsd/xdr.h
index 69a6efc..082f262 100644 (file)
--- a/fs/nfsd/xdr.h
+++ b/fs/nfsd/xdr.h
@@ -106,15 +106,20 @@ struct nfsd_readres {
 };
 
 struct nfsd_readdirres {
+       /* Components of the reply */
        __be32                  status;
 
        int                     count;
 
+       /* Used to encode the reply's entry list */
+       struct xdr_stream       xdr;
+       struct xdr_buf          dirlist;
        struct readdir_cd       common;
        __be32 *                buffer;
        int                     buflen;
        __be32 *                offset;
        struct page             *page;
+       unsigned int            cookie_offset;
 };
 
 struct nfsd_statfsres {
@@ -159,6 +164,8 @@ int nfssvc_encode_statfsres(struct svc_rqst *, __be32 *);
 int nfssvc_encode_readdirres(struct svc_rqst *, __be32 *);
 
 void nfssvc_encode_nfscookie(struct nfsd_readdirres *resp, u32 offset);
+int nfs2svc_encode_entry(void *data, const char *name, int namlen,
+                        loff_t offset, u64 ino, unsigned int d_type);
 int nfssvc_encode_entry(void *, const char *name,
                        int namlen, loff_t offset, u64 ino, unsigned int);