Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 496c262c authored by Andy Adamson's avatar Andy Adamson Committed by J. Bruce Fields
Browse files

nfsd41: check encode size for sessions maxresponse cached 



Calculate the space the compound response has taken after encoding the current
operation.

pad: add on 8 bytes for the next operation's op_code and status so that
there is room to cache a failure on the next operation.

Compare this length to the session se_fmaxresp_cached and return
nfserr_rep_too_big_to_cache if the length is too large.

Our se_fmaxresp_cached will always be a multiple of PAGE_SIZE, and so
will be at least a page and will therefore hold the xdr_buf head.

Signed-off-by: default avatarAndy Adamson <andros@netapp.com>
[nfsd41: non-page DRC for solo sequence responses]
[fixed nfsd4_check_drc_limit cosmetics]
Signed-off-by: default avatarBenny Halevy <bhalevy@panasas.com>
[nfsd41: use cstate session in nfsd4_check_drc_limit]
Signed-off-by: default avatarAndy Adamson <andros@netapp.com>
Signed-off-by: default avatarBenny Halevy <bhalevy@panasas.com>
Signed-off-by: default avatarJ. Bruce Fields <bfields@citi.umich.edu>
parent 6668958f

fs/nfsd/nfs4xdr.c

+51 −0
Original line number Diff line number Diff line
@@ -3078,6 +3078,54 @@ static nfsd4_enc nfsd4_enc_ops[] = { 
	[OP_RECLAIM_COMPLETE]	= (nfsd4_enc)nfsd4_encode_noop,

};



/*

 * Calculate the total amount of memory that the compound response has taken

 * after encoding the current operation.

 *

 * pad: add on 8 bytes for the next operation's op_code and status so that

 * there is room to cache a failure on the next operation.

 *

 * Compare this length to the session se_fmaxresp_cached.

 *

 * Our se_fmaxresp_cached will always be a multiple of PAGE_SIZE, and so

 * will be at least a page and will therefore hold the xdr_buf head.

 */

static int nfsd4_check_drc_limit(struct nfsd4_compoundres *resp)

{

	int status = 0;

	struct xdr_buf *xb = &resp->rqstp->rq_res;

	struct nfsd4_compoundargs *args = resp->rqstp->rq_argp;

	struct nfsd4_session *session = NULL;

	struct nfsd4_slot *slot = resp->cstate.slot;

	u32 length, tlen = 0, pad = 8;



	if (!nfsd4_has_session(&resp->cstate))

		return status;



	session = resp->cstate.session;

	if (session == NULL || slot->sl_cache_entry.ce_cachethis == 0)

		return status;



	if (resp->opcnt >= args->opcnt)

		pad = 0; /* this is the last operation */



	if (xb->page_len == 0) {

		length = (char *)resp->p - (char *)xb->head[0].iov_base + pad;

	} else {

		if (xb->tail[0].iov_base && xb->tail[0].iov_len > 0)

			tlen = (char *)resp->p - (char *)xb->tail[0].iov_base;



		length = xb->head[0].iov_len + xb->page_len + tlen + pad;

	}

	dprintk("%s length %u, xb->page_len %u tlen %u pad %u\n", __func__,

		length, xb->page_len, tlen, pad);



	if (length <= session->se_fmaxresp_cached)

		return status;

	else

		return nfserr_rep_too_big_to_cache;

}



void

nfsd4_encode_operation(struct nfsd4_compoundres *resp, struct nfsd4_op *op)

{
@@ -3094,6 +3142,9 @@ nfsd4_encode_operation(struct nfsd4_compoundres *resp, struct nfsd4_op *op) 
	BUG_ON(op->opnum < 0 || op->opnum >= ARRAY_SIZE(nfsd4_enc_ops) ||

	       !nfsd4_enc_ops[op->opnum]);

	op->status = nfsd4_enc_ops[op->opnum](resp, op->status, &op->u);

	/* nfsd4_check_drc_limit guarantees enough room for error status */

	if (!op->status && nfsd4_check_drc_limit(resp))

		op->status = nfserr_rep_too_big_to_cache;

status:

	/*

	 * Note: We write the status directly, instead of using WRITE32(),