Commit 7f87fc2d authored by Chuck Lever's avatar Chuck Lever
Browse files

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: default avatarChuck Lever <chuck.lever@oracle.com>
parent e4ccfe30

fs/nfsd/nfs3proc.c

+21 −14
Original line number Diff line number Diff line
@@ -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);

fs/nfsd/nfs3xdr.c

+154 −12
Original line number Diff line number Diff line
@@ -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 @@ static __be32 *encode_entryplus_baggage(struct nfsd3_readdirres *cd, __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_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)

fs/nfsd/xdr3.h

+10 −4
Original line number Diff line number Diff line
@@ -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);