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bf51c52a1f
nfsd_cache_csum() currently assumes that the server's RPC layer has been advancing rq_arg.head[0].iov_base as it decodes an incoming request, because that's the way it used to work. On entry, it expects that buf->head[0].iov_base points to the start of the NFS header, and excludes the already-decoded RPC header. These days however, head[0].iov_base now points to the start of the RPC header during all processing. It no longer points at the NFS Call header when execution arrives at nfsd_cache_csum(). In a retransmitted RPC the XID and the NFS header are supposed to be the same as the original message, but the contents of the retransmitted RPC header can be different. For example, for krb5, the GSS sequence number will be different between the two. Thus if the RPC header is always included in the DRC checksum computation, the checksum of the retransmitted message might not match the checksum of the original message, even though the NFS part of these messages is identical. The result is that, even if a matching XID is found in the DRC, the checksum mismatch causes the server to execute the retransmitted RPC transaction again. Reviewed-by: Jeff Layton <jlayton@kernel.org> Tested-by: Jeff Layton <jlayton@kernel.org> Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
94 lines
2.2 KiB
C
94 lines
2.2 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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/*
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* Request reply cache. This was heavily inspired by the
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* implementation in 4.3BSD/4.4BSD.
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*
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* Copyright (C) 1995, 1996 Olaf Kirch <okir@monad.swb.de>
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*/
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#ifndef NFSCACHE_H
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#define NFSCACHE_H
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#include <linux/sunrpc/svc.h>
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#include "netns.h"
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/*
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* Representation of a reply cache entry.
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*
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* Note that we use a sockaddr_in6 to hold the address instead of the more
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* typical sockaddr_storage. This is for space reasons, since sockaddr_storage
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* is much larger than a sockaddr_in6.
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*/
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struct nfsd_cacherep {
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struct {
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/* Keep often-read xid, csum in the same cache line: */
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__be32 k_xid;
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__wsum k_csum;
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u32 k_proc;
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u32 k_prot;
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u32 k_vers;
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unsigned int k_len;
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struct sockaddr_in6 k_addr;
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} c_key;
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struct rb_node c_node;
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struct list_head c_lru;
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unsigned char c_state, /* unused, inprog, done */
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c_type, /* status, buffer */
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c_secure : 1; /* req came from port < 1024 */
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unsigned long c_timestamp;
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union {
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struct kvec u_vec;
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__be32 u_status;
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} c_u;
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};
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#define c_replvec c_u.u_vec
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#define c_replstat c_u.u_status
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/* cache entry states */
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enum {
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RC_UNUSED,
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RC_INPROG,
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RC_DONE
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};
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/* return values */
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enum {
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RC_DROPIT,
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RC_REPLY,
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RC_DOIT
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};
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/*
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* Cache types.
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* We may want to add more types one day, e.g. for diropres and
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* attrstat replies. Using cache entries with fixed length instead
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* of buffer pointers may be more efficient.
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*/
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enum {
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RC_NOCACHE,
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RC_REPLSTAT,
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RC_REPLBUFF,
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};
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/* Cache entries expire after this time period */
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#define RC_EXPIRE (120 * HZ)
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/* Checksum this amount of the request */
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#define RC_CSUMLEN (256U)
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int nfsd_drc_slab_create(void);
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void nfsd_drc_slab_free(void);
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int nfsd_net_reply_cache_init(struct nfsd_net *nn);
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void nfsd_net_reply_cache_destroy(struct nfsd_net *nn);
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int nfsd_reply_cache_init(struct nfsd_net *);
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void nfsd_reply_cache_shutdown(struct nfsd_net *);
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int nfsd_cache_lookup(struct svc_rqst *rqstp, unsigned int start,
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unsigned int len, struct nfsd_cacherep **cacherep);
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void nfsd_cache_update(struct svc_rqst *rqstp, struct nfsd_cacherep *rp,
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int cachetype, __be32 *statp);
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int nfsd_reply_cache_stats_show(struct seq_file *m, void *v);
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#endif /* NFSCACHE_H */
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