Re: [PATCH 01/17] NFS: Introduce new-style XDR encoding functions for NFSv2

[Chuck Lever <chuck.lever@oracle.com>]

Hi Boaz-

On Nov 18, 2010, at 7:50 AM, Boaz Harrosh wrote:

> On 11/17/2010 07:43 PM, Chuck Lever wrote:
>> We're interested in taking advantage of the safety benefits of
>> xdr_streams.  These data structures allow more careful checking for
>> buffer overflow while encoding.  More careful type checking is also
>> introduced in the new functions.
>> 
>> For efficiency, we also eventually want to be able to pass xdr_streams
>> from call_encode() to all XDR encoding functions, rather than building
>> an xdr_stream in every XDR encoding function in the kernel.  To do
>> this means all encoders must be ready to handle a passed-in
>> xdr_stream.
>> 
>> We follow the modern paradigm for encoders of BUGging on error and
>> always returning a zero status code.
>> 
>> Static helper functions are left without the "inline" directive.  This
>> allows the compiler to choose automatically how to optimize these for
>> size or speed.
>> 
>> Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
>> Tested-by: J. Bruce Fields <bfields@redhat.com>
>> ---
>> 
>> fs/nfs/nfs2xdr.c |  406 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
>> 1 files changed, 403 insertions(+), 3 deletions(-)
>> 
>> diff --git a/fs/nfs/nfs2xdr.c b/fs/nfs/nfs2xdr.c
>> index e6bf457..77a3eb9 100644
>> --- a/fs/nfs/nfs2xdr.c
>> +++ b/fs/nfs/nfs2xdr.c
>> @@ -61,6 +61,23 @@
>> #define NFS_readdirres_sz	(1)
>> #define NFS_statfsres_sz	(1+NFS_info_sz)
>> 
>> +
>> +/*
>> + * While encoding arguments, set up the reply buffer in advance to
>> + * receive reply data directly into the page cache.
>> + */
>> +static void prepare_reply_buffer(struct rpc_rqst *req, struct page **pages,
>> +				 unsigned int base, unsigned int len,
>> +				 unsigned int bufsize)
>> +{
>> +	struct rpc_auth	*auth = req->rq_cred->cr_auth;
>> +	unsigned int replen;
>> +
>> +	replen = RPC_REPHDRSIZE + auth->au_rslack + bufsize;
>> +	xdr_inline_pages(&req->rq_rcv_buf, replen << 2, pages, base, len);
>> +}
>> +
>> +
>> /*
>>  * Common NFS XDR functions as inlines
>>  */
>> @@ -81,7 +98,7 @@ xdr_decode_fhandle(__be32 *p, struct nfs_fh *fhandle)
>> }
>> 
>> static inline __be32*
>> -xdr_encode_time(__be32 *p, struct timespec *timep)
>> +xdr_encode_time(__be32 *p, const struct timespec *timep)
>> {
>> 	*p++ = htonl(timep->tv_sec);
> 
> Please use cpu_to_beXX like below?

That's almost certainly updated in a later patch in this series.  Probably [03/17]?

> Boaz
> 
>> 	/* Convert nanoseconds into microseconds */
>> @@ -90,7 +107,7 @@ xdr_encode_time(__be32 *p, struct timespec *timep)
>> }
>> 
>> static inline __be32*
>> -xdr_encode_current_server_time(__be32 *p, struct timespec *timep)
>> +xdr_encode_current_server_time(__be32 *p, const struct timespec *timep)
>> {
>> 	/*
>> 	 * Passing the invalid value useconds=1000000 is a
>> @@ -174,6 +191,136 @@ xdr_encode_sattr(__be32 *p, struct iattr *attr)
>> }
>> 
>> /*
>> + * Encode/decode NFSv2 basic data types
>> + *
>> + * Basic NFSv2 data types are defined in section 2.3 of RFC 1094:
>> + * "NFS: Network File System Protocol Specification".
>> + *
>> + * Not all basic data types have their own encoding and decoding
>> + * functions.  For run-time efficiency, some data types are encoded
>> + * or decoded inline.
>> + */
>> +
>> +/*
>> + * 2.3.3.  fhandle
>> + *
>> + *	typedef opaque fhandle[FHSIZE];
>> + */
>> +static void encode_fhandle(struct xdr_stream *xdr, const struct nfs_fh *fh)
>> +{
>> +	__be32 *p;
>> +
>> +	BUG_ON(fh->size != NFS2_FHSIZE);
>> +	p = xdr_reserve_space(xdr, NFS2_FHSIZE);
>> +	memcpy(p, fh->data, NFS2_FHSIZE);
>> +}
>> +
>> +/*
>> + * 2.3.6.  sattr
>> + *
>> + *	struct sattr {
>> + *		unsigned int	mode;
>> + *		unsigned int	uid;
>> + *		unsigned int	gid;
>> + *		unsigned int	size;
>> + *		timeval		atime;
>> + *		timeval		mtime;
>> + *	};
>> + */
>> +
>> +#define NFS2_SATTR_NOT_SET	(0xffffffff)
>> +
>> +static __be32 *xdr_time_not_set(__be32 *p)
>> +{
>> +	*p++ = cpu_to_be32(NFS2_SATTR_NOT_SET);
>> +	*p++ = cpu_to_be32(NFS2_SATTR_NOT_SET);
>> +	return p;
>> +}
>> +
>> +static void encode_sattr(struct xdr_stream *xdr, const struct iattr *attr)
>> +{
>> +	__be32 *p;
>> +
>> +	p = xdr_reserve_space(xdr, NFS_sattr_sz << 2);
>> +
>> +	if (attr->ia_valid & ATTR_MODE)
>> +		*p++ = cpu_to_be32(attr->ia_mode);
>> +	else
>> +		*p++ = cpu_to_be32(NFS2_SATTR_NOT_SET);
>> +	if (attr->ia_valid & ATTR_UID)
>> +		*p++ = cpu_to_be32(attr->ia_uid);
>> +	else
>> +		*p++ = cpu_to_be32(NFS2_SATTR_NOT_SET);
>> +	if (attr->ia_valid & ATTR_GID)
>> +		*p++ = cpu_to_be32(attr->ia_gid);
>> +	else
>> +		*p++ = cpu_to_be32(NFS2_SATTR_NOT_SET);
>> +	if (attr->ia_valid & ATTR_SIZE)
>> +		*p++ = cpu_to_be32((u32)attr->ia_size);
>> +	else
>> +		*p++ = cpu_to_be32(NFS2_SATTR_NOT_SET);
>> +
>> +	if (attr->ia_valid & ATTR_ATIME_SET)
>> +		p = xdr_encode_time(p, &attr->ia_atime);
>> +	else if (attr->ia_valid & ATTR_ATIME)
>> +		p = xdr_encode_current_server_time(p, &attr->ia_atime);
>> +	else
>> +		p = xdr_time_not_set(p);
>> +	if (attr->ia_valid & ATTR_MTIME_SET)
>> +		xdr_encode_time(p, &attr->ia_mtime);
>> +	else if (attr->ia_valid & ATTR_MTIME)
>> +		xdr_encode_current_server_time(p, &attr->ia_mtime);
>> +	else
>> +		xdr_time_not_set(p);
>> +}
>> +
>> +/*
>> + * 2.3.7.  filename
>> + *
>> + *	typedef string filename<MAXNAMLEN>;
>> + */
>> +static void encode_filename(struct xdr_stream *xdr,
>> +			    const char *name, u32 length)
>> +{
>> +	__be32 *p;
>> +
>> +	BUG_ON(length > NFS2_MAXNAMLEN);
>> +	p = xdr_reserve_space(xdr, 4 + length);
>> +	xdr_encode_opaque(p, name, length);
>> +}
>> +
>> +/*
>> + * 2.3.8.  path
>> + *
>> + *	typedef string path<MAXPATHLEN>;
>> + */
>> +static void encode_path(struct xdr_stream *xdr, struct page **pages, u32 length)
>> +{
>> +	__be32 *p;
>> +
>> +	BUG_ON(length > NFS2_MAXPATHLEN);
>> +	p = xdr_reserve_space(xdr, 4);
>> +	*p = cpu_to_be32(length);
>> +	xdr_write_pages(xdr, pages, 0, length);
>> +}
>> +
>> +/*
>> + * 2.3.10.  diropargs
>> + *
>> + *	struct diropargs {
>> + *		fhandle  dir;
>> + *		filename name;
>> + *	};
>> + */
>> +static void encode_diropargs(struct xdr_stream *xdr, const struct nfs_fh *fh,
>> +			     const char *name, u32 length)
>> +{
>> +	encode_fhandle(xdr, fh);
>> +	encode_filename(xdr, name, length);
>> +}
>> +
>> +
>> +/*
>>  * NFS encode functions
>>  */
>> /*
>> @@ -188,6 +335,16 @@ nfs_xdr_fhandle(struct rpc_rqst *req, __be32 *p, struct nfs_fh *fh)
>> 	return 0;
>> }
>> 
>> +static int nfs2_xdr_enc_fhandle(struct rpc_rqst *req, __be32 *p,
>> +				const struct nfs_fh *fh)
>> +{
>> +	struct xdr_stream xdr;
>> +
>> +	xdr_init_encode(&xdr, &req->rq_snd_buf, p);
>> +	encode_fhandle(&xdr, fh);
>> +	return 0;
>> +}
>> +
>> /*
>>  * Encode SETATTR arguments
>>  */
>> @@ -201,6 +358,25 @@ nfs_xdr_sattrargs(struct rpc_rqst *req, __be32 *p, struct nfs_sattrargs *args)
>> }
>> 
>> /*
>> + * 2.2.3.  sattrargs
>> + *
>> + *	struct sattrargs {
>> + *		fhandle file;
>> + *		sattr attributes;
>> + *	};
>> + */
>> +static int nfs2_xdr_enc_sattrargs(struct rpc_rqst *req, __be32 *p,
>> +				  const struct nfs_sattrargs *args)
>> +{
>> +	struct xdr_stream xdr;
>> +
>> +	xdr_init_encode(&xdr, &req->rq_snd_buf, p);
>> +	encode_fhandle(&xdr, args->fh);
>> +	encode_sattr(&xdr, args->sattr);
>> +	return 0;
>> +}
>> +
>> +/*
>>  * Encode directory ops argument
>>  * LOOKUP, RMDIR
>>  */
>> @@ -213,6 +389,16 @@ nfs_xdr_diropargs(struct rpc_rqst *req, __be32 *p, struct nfs_diropargs *args)
>> 	return 0;
>> }
>> 
>> +static int nfs2_xdr_enc_diropargs(struct rpc_rqst *req, __be32 *p,
>> +				  const struct nfs_diropargs *args)
>> +{
>> +	struct xdr_stream xdr;
>> +
>> +	xdr_init_encode(&xdr, &req->rq_snd_buf, p);
>> +	encode_diropargs(&xdr, args->fh, args->name, args->len);
>> +	return 0;
>> +}
>> +
>> /*
>>  * Encode REMOVE argument
>>  */
>> @@ -225,6 +411,18 @@ nfs_xdr_removeargs(struct rpc_rqst *req, __be32 *p, const struct nfs_removeargs
>> 	return 0;
>> }
>> 
>> +static int nfs2_xdr_enc_readlinkargs(struct rpc_rqst *req, __be32 *p,
>> +				     const struct nfs_readlinkargs *args)
>> +{
>> +	struct xdr_stream xdr;
>> +
>> +	xdr_init_encode(&xdr, &req->rq_snd_buf, p);
>> +	encode_fhandle(&xdr, args->fh);
>> +	prepare_reply_buffer(req, args->pages, args->pgbase,
>> +					args->pglen, NFS_readlinkres_sz);
>> +	return 0;
>> +}
>> +
>> /*
>>  * Arguments to a READ call. Since we read data directly into the page
>>  * cache, we also set up the reply iovec here so that iov[1] points
>> @@ -253,6 +451,44 @@ nfs_xdr_readargs(struct rpc_rqst *req, __be32 *p, struct nfs_readargs *args)
>> }
>> 
>> /*
>> + * 2.2.7.  readargs
>> + *
>> + *	struct readargs {
>> + *		fhandle file;
>> + *		unsigned offset;
>> + *		unsigned count;
>> + *		unsigned totalcount;
>> + *	};
>> + */
>> +static void encode_readargs(struct xdr_stream *xdr,
>> +			    const struct nfs_readargs *args)
>> +{
>> +	u32 offset = args->offset;
>> +	u32 count = args->count;
>> +	__be32 *p;
>> +
>> +	encode_fhandle(xdr, args->fh);
>> +
>> +	p = xdr_reserve_space(xdr, 4 + 4 + 4);
>> +	*p++ = cpu_to_be32(offset);
>> +	*p++ = cpu_to_be32(count);
>> +	*p = cpu_to_be32(count);
>> +}
>> +
>> +static int nfs2_xdr_enc_readargs(struct rpc_rqst *req, __be32 *p,
>> +				 const struct nfs_readargs *args)
>> +{
>> +	struct xdr_stream xdr;
>> +
>> +	xdr_init_encode(&xdr, &req->rq_snd_buf, p);
>> +	encode_readargs(&xdr, args);
>> +	prepare_reply_buffer(req, args->pages, args->pgbase,
>> +					args->count, NFS_readres_sz);
>> +	req->rq_rcv_buf.flags |= XDRBUF_READ;
>> +	return 0;
>> +}
>> +
>> +/*
>>  * Decode READ reply
>>  */
>> static int
>> @@ -318,6 +554,47 @@ nfs_xdr_writeargs(struct rpc_rqst *req, __be32 *p, struct nfs_writeargs *args)
>> }
>> 
>> /*
>> + * 2.2.9.  writeargs
>> + *
>> + *	struct writeargs {
>> + *		fhandle file;
>> + *		unsigned beginoffset;
>> + *		unsigned offset;
>> + *		unsigned totalcount;
>> + *		nfsdata data;
>> + *	};
>> + */
>> +static void encode_writeargs(struct xdr_stream *xdr,
>> +			     const struct nfs_writeargs *args)
>> +{
>> +	u32 offset = args->offset;
>> +	u32 count = args->count;
>> +	__be32 *p;
>> +
>> +	encode_fhandle(xdr, args->fh);
>> +
>> +	p = xdr_reserve_space(xdr, 4 + 4 + 4 + 4);
>> +	*p++ = cpu_to_be32(offset);
>> +	*p++ = cpu_to_be32(offset);
>> +	*p++ = cpu_to_be32(count);
>> +
>> +	/* nfsdata */
>> +	*p = cpu_to_be32(count);
>> +	xdr_write_pages(xdr, args->pages, args->pgbase, count);
>> +}
>> +
>> +static int nfs2_xdr_enc_writeargs(struct rpc_rqst *req, __be32 *p,
>> +				  const struct nfs_writeargs *args)
>> +{
>> +	struct xdr_stream xdr;
>> +
>> +	xdr_init_encode(&xdr, &req->rq_snd_buf, p);
>> +	encode_writeargs(&xdr, args);
>> +	xdr.buf->flags |= XDRBUF_WRITE;
>> +	return 0;
>> +}
>> +
>> +/*
>>  * Encode create arguments
>>  * CREATE, MKDIR
>>  */
>> @@ -332,6 +609,35 @@ nfs_xdr_createargs(struct rpc_rqst *req, __be32 *p, struct nfs_createargs *args)
>> }
>> 
>> /*
>> + * 2.2.10.  createargs
>> + *
>> + *	struct createargs {
>> + *		diropargs where;
>> + *		sattr attributes;
>> + *	};
>> + */
>> +static int nfs2_xdr_enc_createargs(struct rpc_rqst *req, __be32 *p,
>> +				   const struct nfs_createargs *args)
>> +{
>> +	struct xdr_stream xdr;
>> +
>> +	xdr_init_encode(&xdr, &req->rq_snd_buf, p);
>> +	encode_diropargs(&xdr, args->fh, args->name, args->len);
>> +	encode_sattr(&xdr, args->sattr);
>> +	return 0;
>> +}
>> +
>> +static int nfs2_xdr_enc_removeargs(struct rpc_rqst *req, __be32 *p,
>> +				   const struct nfs_removeargs *args)
>> +{
>> +	struct xdr_stream xdr;
>> +
>> +	xdr_init_encode(&xdr, &req->rq_snd_buf, p);
>> +	encode_diropargs(&xdr, args->fh, args->name.name, args->name.len);
>> +	return 0;
>> +}
>> +
>> +/*
>>  * Encode RENAME arguments
>>  */
>> static int
>> @@ -346,6 +652,27 @@ nfs_xdr_renameargs(struct rpc_rqst *req, __be32 *p, struct nfs_renameargs *args)
>> }
>> 
>> /*
>> + * 2.2.12.  renameargs
>> + *
>> + *	struct renameargs {
>> + *		diropargs from;
>> + *		diropargs to;
>> + *	};
>> + */
>> +static int nfs2_xdr_enc_renameargs(struct rpc_rqst *req, __be32 *p,
>> +				   const struct nfs_renameargs *args)
>> +{
>> +	const struct qstr *old = args->old_name;
>> +	const struct qstr *new = args->new_name;
>> +	struct xdr_stream xdr;
>> +
>> +	xdr_init_encode(&xdr, &req->rq_snd_buf, p);
>> +	encode_diropargs(&xdr, args->old_dir, old->name, old->len);
>> +	encode_diropargs(&xdr, args->new_dir, new->name, new->len);
>> +	return 0;
>> +}
>> +
>> +/*
>>  * Encode LINK arguments
>>  */
>> static int
>> @@ -359,6 +686,25 @@ nfs_xdr_linkargs(struct rpc_rqst *req, __be32 *p, struct nfs_linkargs *args)
>> }
>> 
>> /*
>> + * 2.2.13.  linkargs
>> + *
>> + *	struct linkargs {
>> + *		fhandle from;
>> + *		diropargs to;
>> + *	};
>> + */
>> +static int nfs2_xdr_enc_linkargs(struct rpc_rqst *req, __be32 *p,
>> +				 const struct nfs_linkargs *args)
>> +{
>> +	struct xdr_stream xdr;
>> +
>> +	xdr_init_encode(&xdr, &req->rq_snd_buf, p);
>> +	encode_fhandle(&xdr, args->fromfh);
>> +	encode_diropargs(&xdr, args->tofh, args->toname, args->tolen);
>> +	return 0;
>> +}
>> +
>> +/*
>>  * Encode SYMLINK arguments
>>  */
>> static int
>> @@ -388,6 +734,27 @@ nfs_xdr_symlinkargs(struct rpc_rqst *req, __be32 *p, struct nfs_symlinkargs *arg
>> }
>> 
>> /*
>> + * 2.2.14.  symlinkargs
>> + *
>> + *	struct symlinkargs {
>> + *		diropargs from;
>> + *		path to;
>> + *		sattr attributes;
>> + *	};
>> + */
>> +static int nfs2_xdr_enc_symlinkargs(struct rpc_rqst *req, __be32 *p,
>> +				    const struct nfs_symlinkargs *args)
>> +{
>> +	struct xdr_stream xdr;
>> +
>> +	xdr_init_encode(&xdr, &req->rq_snd_buf, p);
>> +	encode_diropargs(&xdr, args->fromfh, args->fromname, args->fromlen);
>> +	encode_path(&xdr, args->pages, args->pathlen);
>> +	encode_sattr(&xdr, args->sattr);
>> +	return 0;
>> +}
>> +
>> +/*
>>  * Encode arguments to readdir call
>>  */
>> static int
>> @@ -409,6 +776,39 @@ nfs_xdr_readdirargs(struct rpc_rqst *req, __be32 *p, struct nfs_readdirargs *arg
>> }
>> 
>> /*
>> + * 2.2.17.  readdirargs
>> + *
>> + *	struct readdirargs {
>> + *		fhandle dir;
>> + *		nfscookie cookie;
>> + *		unsigned count;
>> + *	};
>> + */
>> +static void encode_readdirargs(struct xdr_stream *xdr,
>> +			       const struct nfs_readdirargs *args)
>> +{
>> +	__be32 *p;
>> +
>> +	encode_fhandle(xdr, args->fh);
>> +
>> +	p = xdr_reserve_space(xdr, 4 + 4);
>> +	*p++ = cpu_to_be32(args->cookie);
>> +	*p = cpu_to_be32(args->count);
>> +}
>> +
>> +static int nfs2_xdr_enc_readdirargs(struct rpc_rqst *req, __be32 *p,
>> +				    const struct nfs_readdirargs *args)
>> +{
>> +	struct xdr_stream xdr;
>> +
>> +	xdr_init_encode(&xdr, &req->rq_snd_buf, p);
>> +	encode_readdirargs(&xdr, args);
>> +	prepare_reply_buffer(req, args->pages, 0,
>> +					args->count, NFS_readdirres_sz);
>> +	return 0;
>> +}
>> +
>> +/*
>>  * Decode the result of a readdir call.
>>  * We're not really decoding anymore, we just leave the buffer untouched
>>  * and only check that it is syntactically correct.
>> @@ -696,7 +1096,7 @@ nfs_stat_to_errno(int stat)
>> #define PROC(proc, argtype, restype, timer)				\
>> [NFSPROC_##proc] = {							\
>> 	.p_proc	    =  NFSPROC_##proc,					\
>> -	.p_encode   =  (kxdrproc_t) nfs_xdr_##argtype,			\
>> +	.p_encode   =  (kxdrproc_t)nfs2_xdr_enc_##argtype,		\
>> 	.p_decode   =  (kxdrproc_t) nfs_xdr_##restype,			\
>> 	.p_arglen   =  NFS_##argtype##_sz,				\
>> 	.p_replen   =  NFS_##restype##_sz,				\
>> 
>> --
>> To unsubscribe from this list: send the line "unsubscribe linux-nfs" in
>> the body of a message to majordomo@vger.kernel.org
>> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>> 
> 

-- 
Chuck Lever
chuck[dot]lever[at]oracle[dot]com