Commit fbd2a05f authored by Anna Schumaker's avatar Anna Schumaker
Browse files

NFSv4.2: Rework scratch handling for READ_PLUS 



Instead of using a tiny, static scratch buffer, we should use a kmalloc()-ed
buffer that is allocated when checking for read plus usage. This lets us
use the buffer before decoding any part of the READ_PLUS operation
instead of setting it right before segment decoding, meaning it should
be a little more robust.

Signed-off-by: default avatarAnna Schumaker <Anna.Schumaker@Netapp.com>
parent e025f0a7

fs/nfs/nfs42xdr.c

+2 −2
Original line number Diff line number Diff line
@@ -1122,7 +1122,6 @@ static int decode_read_plus(struct xdr_stream *xdr, struct nfs_pgio_res *res) 
	uint32_t segments;

	struct read_plus_segment *segs;

	int status, i;

	char scratch_buf[16];

	__be32 *p;



	status = decode_op_hdr(xdr, OP_READ_PLUS);
@@ -1143,7 +1142,6 @@ static int decode_read_plus(struct xdr_stream *xdr, struct nfs_pgio_res *res) 
	if (!segs)

		return -ENOMEM;



	xdr_set_scratch_buffer(xdr, &scratch_buf, sizeof(scratch_buf));

	status = -EIO;

	for (i = 0; i < segments; i++) {

		status = decode_read_plus_segment(xdr, &segs[i]);
@@ -1348,6 +1346,8 @@ static int nfs4_xdr_dec_read_plus(struct rpc_rqst *rqstp, 
	struct compound_hdr hdr;

	int status;



	xdr_set_scratch_buffer(xdr, res->scratch, sizeof(res->scratch));



	status = decode_compound_hdr(xdr, &hdr);

	if (status)

		goto out;

fs/nfs/nfs4proc.c

+12 −5
Original line number Diff line number Diff line
@@ -5439,6 +5439,8 @@ static bool nfs4_read_plus_not_supported(struct rpc_task *task, 


static int nfs4_read_done(struct rpc_task *task, struct nfs_pgio_header *hdr)

{

	if (hdr->res.scratch)

		kfree(hdr->res.scratch);

	if (!nfs4_sequence_done(task, &hdr->res.seq_res))

		return -EAGAIN;

	if (nfs4_read_stateid_changed(task, &hdr->args))
@@ -5452,17 +5454,22 @@ static int nfs4_read_done(struct rpc_task *task, struct nfs_pgio_header *hdr) 
}



#if defined CONFIG_NFS_V4_2 && defined CONFIG_NFS_V4_2_READ_PLUS

static void nfs42_read_plus_support(struct nfs_pgio_header *hdr,

static bool nfs42_read_plus_support(struct nfs_pgio_header *hdr,

				    struct rpc_message *msg)

{

	/* Note: We don't use READ_PLUS with pNFS yet */

	if (nfs_server_capable(hdr->inode, NFS_CAP_READ_PLUS) && !hdr->ds_clp)

	if (nfs_server_capable(hdr->inode, NFS_CAP_READ_PLUS) && !hdr->ds_clp) {

		msg->rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_READ_PLUS];

		hdr->res.scratch = kmalloc(32, GFP_KERNEL);

		return hdr->res.scratch != NULL;

	}

	return false;

}

#else

static void nfs42_read_plus_support(struct nfs_pgio_header *hdr,

static bool nfs42_read_plus_support(struct nfs_pgio_header *hdr,

				    struct rpc_message *msg)

{

	return false;

}

#endif /* CONFIG_NFS_V4_2 */
@@ -5472,8 +5479,8 @@ static void nfs4_proc_read_setup(struct nfs_pgio_header *hdr, 
	hdr->timestamp   = jiffies;

	if (!hdr->pgio_done_cb)

		hdr->pgio_done_cb = nfs4_read_done_cb;

	if (!nfs42_read_plus_support(hdr, msg))

		msg->rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_READ];

	nfs42_read_plus_support(hdr, msg);

	nfs4_init_sequence(&hdr->args.seq_args, &hdr->res.seq_res, 0, 0);

}

include/linux/nfs_xdr.h

+1 −0
Original line number Diff line number Diff line
@@ -670,6 +670,7 @@ struct nfs_pgio_res { 
		struct {

			unsigned int		replen;		/* used by read */

			int			eof;		/* used by read */

			void *			scratch;	/* used by read */

		};

		struct {

			struct nfs_writeverf *	verf;		/* used by write */