Commit c1346a12 authored by Chuck Lever's avatar Chuck Lever
Browse files

NFSD: Replace the internals of the READ_BUF() macro 



Convert the READ_BUF macro in nfs4xdr.c from open code to instead
use the new xdr_stream-style decoders already in use by the encode
side (and by the in-kernel NFS client implementation). Once this
conversion is done, each individual NFSv4 argument decoder can be
independently cleaned up to replace these macros with C code.

Signed-off-by: default avatarChuck Lever <chuck.lever@oracle.com>
parent 08281341

fs/nfsd/nfs4proc.c

+2 −2
Original line number Diff line number Diff line
@@ -1023,8 +1023,8 @@ nfsd4_write(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate, 


	write->wr_how_written = write->wr_stable_how;



	nvecs = svc_fill_write_vector(rqstp, write->wr_pagelist,

				      &write->wr_head, write->wr_buflen);

	nvecs = svc_fill_write_vector(rqstp, write->wr_payload.pages,

				      write->wr_payload.head, write->wr_buflen);

	WARN_ON_ONCE(nvecs > ARRAY_SIZE(rqstp->rq_vec));



	status = nfsd_vfs_write(rqstp, &cstate->current_fh, nf,

fs/nfsd/nfs4xdr.c

+26 −155
Original line number Diff line number Diff line
@@ -131,91 +131,14 @@ xdr_error: \ 
	memcpy((x), p, nbytes);			\

	p += XDR_QUADLEN(nbytes);		\

} while (0)



/* READ_BUF, read_buf(): nbytes must be <= PAGE_SIZE */

#define READ_BUF(nbytes)  do {			\

	if (nbytes <= (u32)((char *)argp->end - (char *)argp->p)) {	\

		p = argp->p;			\

		argp->p += XDR_QUADLEN(nbytes);	\

	} else if (!(p = read_buf(argp, nbytes))) { \

		dprintk("NFSD: xdr error (%s:%d)\n", \

				__FILE__, __LINE__); \

#define READ_BUF(nbytes)			\

	do {					\

		p = xdr_inline_decode(argp->xdr,\

				      nbytes);	\

		if (!p)				\

			goto xdr_error;		\

	}					\

	} while (0)



static void next_decode_page(struct nfsd4_compoundargs *argp)

{

	argp->p = page_address(argp->pagelist[0]);

	argp->pagelist++;

	if (argp->pagelen < PAGE_SIZE) {

		argp->end = argp->p + XDR_QUADLEN(argp->pagelen);

		argp->pagelen = 0;

	} else {

		argp->end = argp->p + (PAGE_SIZE>>2);

		argp->pagelen -= PAGE_SIZE;

	}

}



static __be32 *read_buf(struct nfsd4_compoundargs *argp, u32 nbytes)

{

	/* We want more bytes than seem to be available.

	 * Maybe we need a new page, maybe we have just run out

	 */

	unsigned int avail = (char *)argp->end - (char *)argp->p;

	__be32 *p;



	if (argp->pagelen == 0) {

		struct kvec *vec = &argp->rqstp->rq_arg.tail[0];



		if (!argp->tail) {

			argp->tail = true;

			avail = vec->iov_len;

			argp->p = vec->iov_base;

			argp->end = vec->iov_base + avail;

		}



		if (avail < nbytes)

			return NULL;



		p = argp->p;

		argp->p += XDR_QUADLEN(nbytes);

		return p;

	}



	if (avail + argp->pagelen < nbytes)

		return NULL;

	if (avail + PAGE_SIZE < nbytes) /* need more than a page !! */

		return NULL;

	/* ok, we can do it with the current plus the next page */

	if (nbytes <= sizeof(argp->tmp))

		p = argp->tmp;

	else {

		kfree(argp->tmpp);

		p = argp->tmpp = kmalloc(nbytes, GFP_KERNEL);

		if (!p)

			return NULL;

		

	}

	/*

	 * The following memcpy is safe because read_buf is always

	 * called with nbytes > avail, and the two cases above both

	 * guarantee p points to at least nbytes bytes.

	 */

	memcpy(p, argp->p, avail);

	next_decode_page(argp);

	memcpy(((char*)p)+avail, argp->p, (nbytes - avail));

	argp->p += XDR_QUADLEN(nbytes - avail);

	return p;

}



static unsigned int compoundargs_bytes_left(struct nfsd4_compoundargs *argp)

{

	unsigned int this = (char *)argp->end - (char *)argp->p;



	return this + argp->pagelen;

}



static int zero_clientid(clientid_t *clid)

{

	return (clid->cl_boot == 0) && (clid->cl_id == 0);
@@ -261,44 +184,6 @@ svcxdr_dupstr(struct nfsd4_compoundargs *argp, void *buf, u32 len) 
	return p;

}



static __be32

svcxdr_construct_vector(struct nfsd4_compoundargs *argp, struct kvec *head,

			struct page ***pagelist, u32 buflen)

{

	int avail;

	int len;

	int pages;



	/* Sorry .. no magic macros for this.. *

	 * READ_BUF(write->wr_buflen);

	 * SAVEMEM(write->wr_buf, write->wr_buflen);

	 */

	avail = (char *)argp->end - (char *)argp->p;

	if (avail + argp->pagelen < buflen) {

		dprintk("NFSD: xdr error (%s:%d)\n",

			       __FILE__, __LINE__);

		return nfserr_bad_xdr;

	}

	head->iov_base = argp->p;

	head->iov_len = avail;

	*pagelist = argp->pagelist;



	len = XDR_QUADLEN(buflen) << 2;

	if (len >= avail) {

		len -= avail;



		pages = len >> PAGE_SHIFT;

		argp->pagelist += pages;

		argp->pagelen -= pages * PAGE_SIZE;

		len -= pages * PAGE_SIZE;



		next_decode_page(argp);

	}

	argp->p += XDR_QUADLEN(len);



	return 0;

}



/**

 * savemem - duplicate a chunk of memory for later processing

 * @argp: NFSv4 compound argument structure to be freed with
@@ -398,7 +283,7 @@ nfsd4_decode_fattr(struct nfsd4_compoundargs *argp, u32 *bmval, 
		READ_BUF(4); len += 4;

		nace = be32_to_cpup(p++);



		if (nace > compoundargs_bytes_left(argp)/20)

		if (nace > xdr_stream_remaining(argp->xdr) / sizeof(struct nfs4_ace))

			/*

			 * Even with 4-byte names there wouldn't be

			 * space for that many aces; something fishy is
@@ -929,7 +814,7 @@ static __be32 nfsd4_decode_share_deny(struct nfsd4_compoundargs *argp, u32 *x) 


static __be32 nfsd4_decode_opaque(struct nfsd4_compoundargs *argp, struct xdr_netobj *o)

{

	__be32 *p;

	DECODE_HEAD;



	READ_BUF(4);

	o->len = be32_to_cpup(p++);
@@ -939,9 +824,8 @@ static __be32 nfsd4_decode_opaque(struct nfsd4_compoundargs *argp, struct xdr_ne 


	READ_BUF(o->len);

	SAVEMEM(o->data, o->len);

	return nfs_ok;

xdr_error:

	return nfserr_bad_xdr;



	DECODE_TAIL;

}



static __be32
@@ -1319,10 +1203,8 @@ nfsd4_decode_write(struct nfsd4_compoundargs *argp, struct nfsd4_write *write) 
		goto xdr_error;

	write->wr_buflen = be32_to_cpup(p++);



	status = svcxdr_construct_vector(argp, &write->wr_head,

					 &write->wr_pagelist, write->wr_buflen);

	if (status)

		return status;

	if (!xdr_stream_subsegment(argp->xdr, &write->wr_payload, write->wr_buflen))

		goto xdr_error;



	DECODE_TAIL;

}
@@ -1891,13 +1773,14 @@ nfsd4_decode_seek(struct nfsd4_compoundargs *argp, struct nfsd4_seek *seek) 
 */



/*

 * Decode data into buffer. Uses head and pages constructed by

 * svcxdr_construct_vector.

 * Decode data into buffer.

 */

static __be32

nfsd4_vbuf_from_vector(struct nfsd4_compoundargs *argp, struct kvec *head,

		       struct page **pages, char **bufp, u32 buflen)

nfsd4_vbuf_from_vector(struct nfsd4_compoundargs *argp, struct xdr_buf *xdr,

		       char **bufp, u32 buflen)

{

	struct page **pages = xdr->pages;

	struct kvec *head = xdr->head;

	char *tmp, *dp;

	u32 len;
@@ -2012,8 +1895,6 @@ nfsd4_decode_setxattr(struct nfsd4_compoundargs *argp, 
{

	DECODE_HEAD;

	u32 flags, maxcount, size;

	struct kvec head;

	struct page **pagelist;



	READ_BUF(4);

	flags = be32_to_cpup(p++);
@@ -2036,11 +1917,11 @@ nfsd4_decode_setxattr(struct nfsd4_compoundargs *argp, 


	setxattr->setxa_len = size;

	if (size > 0) {

		status = svcxdr_construct_vector(argp, &head, &pagelist, size);

		if (status)

			return status;

		struct xdr_buf payload;



		status = nfsd4_vbuf_from_vector(argp, &head, pagelist,

		if (!xdr_stream_subsegment(argp->xdr, &payload, size))

			goto xdr_error;

		status = nfsd4_vbuf_from_vector(argp, &payload,

						&setxattr->setxa_buf, size);

	}
@@ -5288,8 +5169,6 @@ void nfsd4_release_compoundargs(struct svc_rqst *rqstp) 
		kfree(args->ops);

		args->ops = args->iops;

	}

	kfree(args->tmpp);

	args->tmpp = NULL;

	while (args->to_free) {

		struct svcxdr_tmpbuf *tb = args->to_free;

		args->to_free = tb->next;
@@ -5302,19 +5181,11 @@ nfs4svc_decode_compoundargs(struct svc_rqst *rqstp, __be32 *p) 
{

	struct nfsd4_compoundargs *args = rqstp->rq_argp;



	if (rqstp->rq_arg.head[0].iov_len % 4) {

		/* client is nuts */

		dprintk("%s: compound not properly padded! (peeraddr=%pISc xid=0x%x)",

			__func__, svc_addr(rqstp), be32_to_cpu(rqstp->rq_xid));

		return 0;

	}

	args->p = p;

	args->end = rqstp->rq_arg.head[0].iov_base + rqstp->rq_arg.head[0].iov_len;

	args->pagelist = rqstp->rq_arg.pages;

	args->pagelen = rqstp->rq_arg.page_len;

	args->tail = false;

	/* svcxdr_tmp_alloc */

	args->tmpp = NULL;

	args->to_free = NULL;



	args->xdr = &rqstp->rq_arg_stream;

	args->ops = args->iops;

	args->rqstp = rqstp;

fs/nfsd/xdr4.h

+2 −8
Original line number Diff line number Diff line
@@ -419,8 +419,7 @@ struct nfsd4_write { 
	u64		wr_offset;          /* request */

	u32		wr_stable_how;      /* request */

	u32		wr_buflen;          /* request */

	struct kvec	wr_head;

	struct page **	wr_pagelist;        /* request */

	struct xdr_buf	wr_payload;         /* request */



	u32		wr_bytes_written;   /* response */

	u32		wr_how_written;     /* response */
@@ -696,15 +695,10 @@ struct svcxdr_tmpbuf { 


struct nfsd4_compoundargs {

	/* scratch variables for XDR decode */

	__be32 *			p;

	__be32 *			end;

	struct page **			pagelist;

	int				pagelen;

	bool				tail;

	__be32				tmp[8];

	__be32 *			tmpp;

	struct xdr_stream		*xdr;

	struct svcxdr_tmpbuf		*to_free;



	struct svc_rqst			*rqstp;



	u32				taglen;

include/linux/sunrpc/xdr.h

+2 −0
Original line number Diff line number Diff line
@@ -254,6 +254,8 @@ extern void xdr_enter_page(struct xdr_stream *xdr, unsigned int len); 
extern int xdr_process_buf(struct xdr_buf *buf, unsigned int offset, unsigned int len, int (*actor)(struct scatterlist *, void *), void *data);

extern uint64_t xdr_align_data(struct xdr_stream *, uint64_t, uint32_t);

extern uint64_t xdr_expand_hole(struct xdr_stream *, uint64_t, uint64_t);

extern bool xdr_stream_subsegment(struct xdr_stream *xdr, struct xdr_buf *subbuf,

				  unsigned int len);



/**

 * xdr_set_scratch_buffer - Attach a scratch buffer for decoding data.

net/sunrpc/xdr.c

+45 −0
Original line number Diff line number Diff line
@@ -1407,6 +1407,51 @@ int xdr_buf_subsegment(const struct xdr_buf *buf, struct xdr_buf *subbuf, 
}

EXPORT_SYMBOL_GPL(xdr_buf_subsegment);



/**

 * xdr_stream_subsegment - set @subbuf to a portion of @xdr

 * @xdr: an xdr_stream set up for decoding

 * @subbuf: the result buffer

 * @nbytes: length of @xdr to extract, in bytes

 *

 * Sets up @subbuf to represent a portion of @xdr. The portion

 * starts at the current offset in @xdr, and extends for a length

 * of @nbytes. If this is successful, @xdr is advanced to the next

 * position following that portion.

 *

 * Return values:

 *   %true: @subbuf has been initialized, and @xdr has been advanced.

 *   %false: a bounds error has occurred

 */

bool xdr_stream_subsegment(struct xdr_stream *xdr, struct xdr_buf *subbuf,

			   unsigned int nbytes)

{

	unsigned int remaining, offset, len;



	if (xdr_buf_subsegment(xdr->buf, subbuf, xdr_stream_pos(xdr), nbytes))

		return false;



	if (subbuf->head[0].iov_len)

		if (!__xdr_inline_decode(xdr, subbuf->head[0].iov_len))

			return false;



	remaining = subbuf->page_len;

	offset = subbuf->page_base;

	while (remaining) {

		len = min_t(unsigned int, remaining, PAGE_SIZE) - offset;



		if (xdr->p == xdr->end && !xdr_set_next_buffer(xdr))

			return false;

		if (!__xdr_inline_decode(xdr, len))

			return false;



		remaining -= len;

		offset = 0;

	}



	return true;

}

EXPORT_SYMBOL_GPL(xdr_stream_subsegment);



/**

 * xdr_buf_trim - lop at most "len" bytes off the end of "buf"

 * @buf: buf to be trimmed