NFSD: Update NFSv3 READDIR entry encoders to use struct xdr_stream

The benefit of the xdr_stream helpers is that they transparently
handle encoding an XDR data item that crosses page boundaries.
Most of the open-coded logic to do that here can be eliminated.

A sub-buffer and sub-stream are set up as a sink buffer for the
directory entry encoder. As an entry is encoded, it is added to
the end of the content in this buffer/stream. The total length of
the directory list is tracked in the buffer's @len field.

When it comes time to encode the Reply, the sub-buffer is merged
into rq_res's page array at the correct place using
xdr_write_pages().

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

diff --git a/fs/nfsd/nfs3proc.c b/fs/nfsd/nfs3proc.c
index f1096aa0f47cc40dbd8348cc7340a6f138aafc75..bc64e95a168d3f01ae076367a8f55d35488e1db1 100644 (file)
--- a/fs/nfsd/nfs3proc.c
+++ b/fs/nfsd/nfs3proc.c
@@ -441,18 +441,30 @@ static void nfsd3_init_dirlist_pages(struct svc_rqst *rqstp,
                                     struct nfsd3_readdirres *resp,
                                     int count)
 {
+       struct xdr_buf *buf = &resp->dirlist;
+       struct xdr_stream *xdr = &resp->xdr;
+
        count = min_t(u32, count, svc_max_payload(rqstp));
 
-       /* 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->pages = rqstp->rq_next_page;
-       resp->buffer = page_address(*resp->pages);
+       /* Reserve room for the NULL ptr & eof flag (-2 words) */
+       buf->buflen = count - XDR_UNIT * 2;
+       buf->pages = rqstp->rq_next_page;
        while (count > 0) {
                rqstp->rq_next_page++;
                count -= PAGE_SIZE;
        }
+
+       /* 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;
 }
 
 /*
@@ -471,16 +483,13 @@ nfsd3_proc_readdir(struct svc_rqst *rqstp)
 
        nfsd3_init_dirlist_pages(rqstp, resp, argp->count);
 
-       /* Read directory and encode entries on the fly */
        fh_copy(&resp->fh, &argp->fh);
-
-       resp->count = 0;
        resp->common.err = nfs_ok;
+       resp->cookie_offset = 0;
        resp->rqstp = rqstp;
        offset = argp->cookie;
-
        resp->status = nfsd_readdir(rqstp, &resp->fh, &offset,
-                                   &resp->common, nfs3svc_encode_entry);
+                                   &resp->common, nfs3svc_encode_entry3);
        memcpy(resp->verf, argp->verf, 8);
        nfs3svc_encode_cookie3(resp, offset);
 
@@ -504,11 +513,9 @@ nfsd3_proc_readdirplus(struct svc_rqst *rqstp)
 
        nfsd3_init_dirlist_pages(rqstp, resp, argp->count);
 
-       /* Read directory and encode entries on the fly */
        fh_copy(&resp->fh, &argp->fh);
-
-       resp->count = 0;
        resp->common.err = nfs_ok;
+       resp->cookie_offset = 0;
        resp->rqstp = rqstp;
        offset = argp->cookie;
 
@@ -522,7 +529,7 @@ nfsd3_proc_readdirplus(struct svc_rqst *rqstp)
        }
 
        resp->status = nfsd_readdir(rqstp, &resp->fh, &offset,
-                                   &resp->common, nfs3svc_encode_entry_plus);
+                                   &resp->common, nfs3svc_encode_entryplus3);
        memcpy(resp->verf, argp->verf, 8);
        nfs3svc_encode_cookie3(resp, offset);
 

diff --git a/fs/nfsd/nfs3xdr.c b/fs/nfsd/nfs3xdr.c
index 3d076d3c5c7b8bb8f4de6810e33e478d09d7fb9e..f38d845ac8a0f3ef8ca639d6c8d263381cbaed16 100644 (file)
--- a/fs/nfsd/nfs3xdr.c
+++ b/fs/nfsd/nfs3xdr.c
@@ -1139,6 +1139,7 @@ nfs3svc_encode_readdirres(struct svc_rqst *rqstp, __be32 *p)
 {
        struct xdr_stream *xdr = &rqstp->rq_res_stream;
        struct nfsd3_readdirres *resp = rqstp->rq_resp;
+       struct xdr_buf *dirlist = &resp->dirlist;
 
        if (!svcxdr_encode_nfsstat3(xdr, resp->status))
                return 0;
@@ -1148,7 +1149,7 @@ nfs3svc_encode_readdirres(struct svc_rqst *rqstp, __be32 *p)
                        return 0;
                if (!svcxdr_encode_cookieverf3(xdr, resp->verf))
                        return 0;
-               xdr_write_pages(xdr, resp->pages, 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;
@@ -1240,21 +1241,18 @@ out:
  * @resp: readdir result context
  * @offset: offset cookie to encode
  *
+ * The buffer space for the offset cookie has already been reserved
+ * by svcxdr_encode_entry3_common().
  */
 void nfs3svc_encode_cookie3(struct nfsd3_readdirres *resp, u64 offset)
 {
-       if (!resp->offset)
-               return;
+       __be64 cookie = cpu_to_be64(offset);
 
-       if (resp->offset1) {
-               /* we ended up with offset on a page boundary */
-               *resp->offset = cpu_to_be32(offset >> 32);
-               *resp->offset1 = cpu_to_be32(offset & 0xffffffff);
-               resp->offset1 = NULL;
-       } else {
-               xdr_encode_hyper(resp->offset, offset);
-       }
-       resp->offset = NULL;
+       if (!resp->cookie_offset)
+               return;
+       write_bytes_to_xdr_buf(&resp->dirlist, resp->cookie_offset, &cookie,
+                              sizeof(cookie));
+       resp->cookie_offset = 0;
 }
 
 /*
@@ -1403,6 +1401,150 @@ nfs3svc_encode_entry_plus(void *cd, const char *name,
        return encode_entry(cd, name, namlen, offset, ino, d_type, 1);
 }
 
+static bool
+svcxdr_encode_entry3_common(struct nfsd3_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_u64(xdr, ino) < 0)
+               return false;
+       /* name */
+       if (xdr_stream_encode_opaque(xdr, name, min(namlen, NFS3_MAXNAMLEN)) < 0)
+               return false;
+       /* cookie */
+       resp->cookie_offset = dirlist->len;
+       if (xdr_stream_encode_u64(xdr, NFS_OFFSET_MAX) < 0)
+               return false;
+
+       return true;
+}
+
+/**
+ * nfs3svc_encode_entry3 - encode one NFSv3 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 nfs3svc_encode_entry3(void *data, const char *name, int namlen,
+                         loff_t offset, u64 ino, unsigned int d_type)
+{
+       struct readdir_cd *ccd = data;
+       struct nfsd3_readdirres *resp = container_of(ccd,
+                                                    struct nfsd3_readdirres,
+                                                    common);
+       unsigned int starting_length = resp->dirlist.len;
+
+       /* The offset cookie for the previous entry */
+       nfs3svc_encode_cookie3(resp, offset);
+
+       if (!svcxdr_encode_entry3_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;
+}
+
+static bool
+svcxdr_encode_entry3_plus(struct nfsd3_readdirres *resp, const char *name,
+                         int namlen, u64 ino)
+{
+       struct xdr_stream *xdr = &resp->xdr;
+       struct svc_fh *fhp = &resp->scratch;
+       bool result;
+
+       result = false;
+       fh_init(fhp, NFS3_FHSIZE);
+       if (compose_entry_fh(resp, fhp, name, namlen, ino) != nfs_ok)
+               goto out_noattrs;
+
+       if (!svcxdr_encode_post_op_attr(resp->rqstp, xdr, fhp))
+               goto out;
+       if (!svcxdr_encode_post_op_fh3(xdr, fhp))
+               goto out;
+       result = true;
+
+out:
+       fh_put(fhp);
+       return result;
+
+out_noattrs:
+       if (xdr_stream_encode_item_absent(xdr) < 0)
+               return false;
+       if (xdr_stream_encode_item_absent(xdr) < 0)
+               return false;
+       return true;
+}
+
+/**
+ * nfs3svc_encode_entryplus3 - encode one NFSv3 READDIRPLUS 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 nfs3svc_encode_entryplus3(void *data, const char *name, int namlen,
+                             loff_t offset, u64 ino, unsigned int d_type)
+{
+       struct readdir_cd *ccd = data;
+       struct nfsd3_readdirres *resp = container_of(ccd,
+                                                    struct nfsd3_readdirres,
+                                                    common);
+       unsigned int starting_length = resp->dirlist.len;
+
+       /* The offset cookie for the previous entry */
+       nfs3svc_encode_cookie3(resp, offset);
+
+       if (!svcxdr_encode_entry3_common(resp, name, namlen, offset, ino))
+               goto out_toosmall;
+       if (!svcxdr_encode_entry3_plus(resp, name, namlen, 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;
+}
+
 static bool
 svcxdr_encode_fsstat3resok(struct xdr_stream *xdr,
                           const struct nfsd3_fsstatres *resp)

diff --git a/fs/nfsd/xdr3.h b/fs/nfsd/xdr3.h
index a4cdd8ccb175aa7845dab21dff30ce44ca6a209b..81dea78b0f17efd8a40e359d84e7ce862b336634 100644 (file)
--- a/fs/nfsd/xdr3.h
+++ b/fs/nfsd/xdr3.h
@@ -169,20 +169,22 @@ struct nfsd3_linkres {
 };
 
 struct nfsd3_readdirres {
+       /* Components of the reply */
        __be32                  status;
        struct svc_fh           fh;
-       /* Just to save kmalloc on every readdirplus entry (svc_fh is a
-        * little large for the stack): */
-       struct svc_fh           scratch;
        int                     count;
        __be32                  verf[2];
-       struct page             **pages;
 
+       /* Used to encode the reply's entry list */
+       struct xdr_stream       xdr;
+       struct xdr_buf          dirlist;
+       struct svc_fh           scratch;
        struct readdir_cd       common;
        __be32 *                buffer;
        int                     buflen;
        __be32 *                offset;
        __be32 *                offset1;
+       unsigned int            cookie_offset;
        struct svc_rqst *       rqstp;
 
 };
@@ -309,6 +311,10 @@ int nfs3svc_encode_entry(void *, const char *name,
 int nfs3svc_encode_entry_plus(void *, const char *name,
                                int namlen, loff_t offset, u64 ino,
                                unsigned int);
+int nfs3svc_encode_entry3(void *data, const char *name, int namlen,
+                         loff_t offset, u64 ino, unsigned int d_type);
+int nfs3svc_encode_entryplus3(void *data, const char *name, int namlen,
+                             loff_t offset, u64 ino, unsigned int d_type);
 /* Helper functions for NFSv3 ACL code */
 __be32 *nfs3svc_encode_post_op_attr(struct svc_rqst *rqstp, __be32 *p,
                                struct svc_fh *fhp);