linux-stable-rt/fs/nfs/callback.h

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/*
* linux/fs/nfs/callback.h
*
* Copyright (C) 2004 Trond Myklebust
*
* NFSv4 callback definitions
*/
#ifndef __LINUX_FS_NFS_CALLBACK_H
#define __LINUX_FS_NFS_CALLBACK_H
#define NFS4_CALLBACK 0x40000000
#define NFS4_CALLBACK_XDRSIZE 2048
#define NFS4_CALLBACK_BUFSIZE (1024 + NFS4_CALLBACK_XDRSIZE)
enum nfs4_callback_procnum {
CB_NULL = 0,
CB_COMPOUND = 1,
};
enum nfs4_callback_opnum {
OP_CB_GETATTR = 3,
OP_CB_RECALL = 4,
OP_CB_ILLEGAL = 10044,
};
struct cb_compound_hdr_arg {
unsigned int taglen;
const char *tag;
unsigned int callback_ident;
unsigned nops;
};
struct cb_compound_hdr_res {
__be32 *status;
unsigned int taglen;
const char *tag;
__be32 *nops;
};
struct cb_getattrargs {
struct sockaddr *addr;
struct nfs_fh fh;
uint32_t bitmap[2];
};
struct cb_getattrres {
__be32 status;
uint32_t bitmap[2];
uint64_t size;
uint64_t change_attr;
struct timespec ctime;
struct timespec mtime;
};
struct cb_recallargs {
struct sockaddr *addr;
struct nfs_fh fh;
nfs4_stateid stateid;
uint32_t truncate;
};
extern __be32 nfs4_callback_getattr(struct cb_getattrargs *args, struct cb_getattrres *res);
extern __be32 nfs4_callback_recall(struct cb_recallargs *args, void *dummy);
#ifdef CONFIG_NFS_V4
extern int nfs_callback_up(u32 minorversion, struct rpc_xprt *xprt);
extern void nfs_callback_down(void);
#else
#define nfs_callback_up() (0)
#define nfs_callback_down() do {} while(0)
#endif
nfs41: Implement NFSv4.1 callback service process. nfs41_callback_up() initializes the necessary queues and creates the new nfs41_callback_svc thread. This thread executes the callback service which waits for requests to arrive on the svc_serv->sv_cb_list. NFS41_BC_MIN_CALLBACKS is set to 1 because we expect callbacks to not cause substantial latency. The actual processing of the callback will be implemented as a separate patch. There is only one NFSv4.1 callback service. The first caller of nfs4_callback_up() creates the service, subsequent callers increment a reference count on the service. The service is destroyed when the last caller invokes nfs_callback_down(). The transport needs to hold a reference to the callback service in order to invoke it during callback processing. Currently this reference is only obtained when the service is first created. This is incorrect, since subsequent registrations for other transports will leave the xprt->serv pointer uninitialized, leading to an oops when a callback arrives on the "unreferenced" transport. This patch fixes the problem by ensuring that a reference to the service is saved in xprt->serv, either because the service is created by this invocation to nfs4_callback_up() or by a prior invocation. Signed-off-by: Ricardo Labiaga <Ricardo.Labiaga@netapp.com> Signed-off-by: Benny Halevy <bhalevy@panasas.com> [nfs41: Add a reference to svc_serv during callback service bring up] Signed-off-by: Ricardo Labiaga <Ricardo.Labiaga@netapp.com> Signed-off-by: Benny Halevy <bhalevy@panasas.com> [Type check arguments of nfs_callback_up] Signed-off-by: Ricardo Labiaga <Ricardo.Labiaga@netapp.com> Signed-off-by: Benny Halevy <bhalevy@panasas.com> [nfs41: save svc_serv in nfs_callback_info] Signed-off-by: Benny Halevy <bhalevy@panasas.com> [Removal of ugly #ifdefs] [nfs41: Update to removal of ugly #ifdefs] Signed-off-by: Ricardo Labiaga <Ricardo.Labiaga@netapp.com> Signed-off-by: Benny Halevy <bhalevy@panasas.com>
2009-04-01 21:23:08 +08:00
/*
* nfs41: Callbacks are expected to not cause substantial latency,
* so we limit their concurrency to 1 by setting up the maximum number
* of slots for the backchannel.
*/
#define NFS41_BC_MIN_CALLBACKS 1
extern unsigned int nfs_callback_set_tcpport;
extern unsigned short nfs_callback_tcpport;
extern unsigned short nfs_callback_tcpport6;
#endif /* __LINUX_FS_NFS_CALLBACK_H */