Commit a61e147e authored by Mike Snitzer's avatar Mike Snitzer Committed by Anna Schumaker
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nfs_common: prepare for the NFS client to use nfsd_file for LOCALIO 



The next commit will introduce nfsd_open_local_fh() which returns an
nfsd_file structure.  This commit exposes LOCALIO's required NFSD
symbols to the NFS client:

- Make nfsd_open_local_fh() symbol and other required NFSD symbols
  available to NFS in a global 'nfs_to' nfsd_localio_operations
  struct (global access suggested by Trond, nfsd_localio_operations
  suggested by NeilBrown).  The next commit will also introduce
  nfsd_localio_ops_init() that init_nfsd() will call to initialize
  'nfs_to'.

- Introduce nfsd_file_file() that provides access to nfsd_file's
  backing file.  Keeps nfsd_file structure opaque to NFS client (as
  suggested by Jeff Layton).

- Introduce nfsd_file_put_local() that will put the reference to the
  nfsd_file's associated nn->nfsd_serv and then put the reference to
  the nfsd_file (as suggested by NeilBrown).

Suggested-by: Trond Myklebust <trond.myklebust@hammerspace.com> # nfs_to
Suggested-by: NeilBrown <neilb@suse.de> # nfsd_localio_operations
Suggested-by: Jeff Layton <jlayton@kernel.org> # nfsd_file_file
Signed-off-by: default avatarMike Snitzer <snitzer@kernel.org>
Reviewed-by: default avatarNeilBrown <neilb@suse.de>
Reviewed-by: default avatarJeff Layton <jlayton@kernel.org>
Signed-off-by: default avatarAnna Schumaker <anna.schumaker@oracle.com>
parent 2a33a85b

fs/nfs_common/nfslocalio.c

+24 −1
Original line number Diff line number Diff line
@@ -72,7 +72,7 @@ void nfs_uuid_is_local(const uuid_t *uuid, struct list_head *list, 
		 * invalidated.

		 */

		list_move(&nfs_uuid->list, list);

		nfs_uuid->net = net;

		rcu_assign_pointer(nfs_uuid->net, net);



		__module_get(mod);

		nfsd_mod = mod;
@@ -114,3 +114,26 @@ void nfs_uuid_invalidate_one_client(nfs_uuid_t *nfs_uuid) 
	}

}

EXPORT_SYMBOL_GPL(nfs_uuid_invalidate_one_client);



/*

 * The NFS LOCALIO code needs to call into NFSD using various symbols,

 * but cannot be statically linked, because that will make the NFS

 * module always depend on the NFSD module.

 *

 * 'nfs_to' provides NFS access to NFSD functions needed for LOCALIO,

 * its lifetime is tightly coupled to the NFSD module and will always

 * be available to NFS LOCALIO because any successful client<->server

 * LOCALIO handshake results in a reference on the NFSD module (above),

 * so NFS implicitly holds a reference to the NFSD module and its

 * functions in the 'nfs_to' nfsd_localio_operations cannot disappear.

 *

 * If the last NFS client using LOCALIO disconnects (and its reference

 * on NFSD dropped) then NFSD could be unloaded, resulting in 'nfs_to'

 * functions being invalid pointers. But if NFSD isn't loaded then NFS

 * will not be able to handshake with NFSD and will have no cause to

 * try to call 'nfs_to' function pointers. If/when NFSD is reloaded it

 * will reinitialize the 'nfs_to' function pointers and make LOCALIO

 * possible.

 */

const struct nfsd_localio_operations *nfs_to;

EXPORT_SYMBOL_GPL(nfs_to);

fs/nfsd/filecache.c

+28 −0
Original line number Diff line number Diff line
@@ -390,6 +390,34 @@ nfsd_file_put(struct nfsd_file *nf) 
		nfsd_file_free(nf);

}



/**

 * nfsd_file_put_local - put the reference to nfsd_file and local nfsd_serv

 * @nf: nfsd_file of which to put the references

 *

 * First put the reference of the nfsd_file and then put the

 * reference to the associated nn->nfsd_serv.

 */

void

nfsd_file_put_local(struct nfsd_file *nf)

{

	struct net *net = nf->nf_net;



	nfsd_file_put(nf);

	nfsd_serv_put(net);

}



/**

 * nfsd_file_file - get the backing file of an nfsd_file

 * @nf: nfsd_file of which to access the backing file.

 *

 * Return backing file for @nf.

 */

struct file *

nfsd_file_file(struct nfsd_file *nf)

{

	return nf->nf_file;

}



static void

nfsd_file_dispose_list(struct list_head *dispose)

{

fs/nfsd/filecache.h

+2 −0
Original line number Diff line number Diff line
@@ -55,7 +55,9 @@ void nfsd_file_cache_shutdown(void); 
int nfsd_file_cache_start_net(struct net *net);

void nfsd_file_cache_shutdown_net(struct net *net);

void nfsd_file_put(struct nfsd_file *nf);

void nfsd_file_put_local(struct nfsd_file *nf);

struct nfsd_file *nfsd_file_get(struct nfsd_file *nf);

struct file *nfsd_file_file(struct nfsd_file *nf);

void nfsd_file_close_inode_sync(struct inode *inode);

void nfsd_file_net_dispose(struct nfsd_net *nn);

bool nfsd_file_is_cached(struct inode *inode);

fs/nfsd/nfssvc.c

+1 −0
Original line number Diff line number Diff line
@@ -19,6 +19,7 @@ 
#include <linux/sunrpc/svc_xprt.h>

#include <linux/lockd/bind.h>

#include <linux/nfsacl.h>

#include <linux/nfslocalio.h>

#include <linux/seq_file.h>

#include <linux/inetdevice.h>

#include <net/addrconf.h>

include/linux/nfslocalio.h

+26 −1
Original line number Diff line number Diff line
@@ -9,6 +9,7 @@ 
#include <linux/module.h>

#include <linux/list.h>

#include <linux/uuid.h>

#include <linux/sunrpc/clnt.h>

#include <linux/sunrpc/svcauth.h>

#include <linux/nfs.h>

#include <net/net_namespace.h>
@@ -22,7 +23,7 @@ 
typedef struct {

	uuid_t uuid;

	struct list_head list;

	struct net *net; /* nfsd's network namespace */

	struct net __rcu *net; /* nfsd's network namespace */

	struct auth_domain *dom; /* auth_domain for localio */

} nfs_uuid_t;
@@ -33,4 +34,28 @@ void nfs_uuid_is_local(const uuid_t *, struct list_head *, 
void nfs_uuid_invalidate_clients(struct list_head *list);

void nfs_uuid_invalidate_one_client(nfs_uuid_t *nfs_uuid);



struct nfsd_file;



/* localio needs to map filehandle -> struct nfsd_file */

extern struct nfsd_file *

nfsd_open_local_fh(struct net *, struct auth_domain *, struct rpc_clnt *,

		   const struct cred *, const struct nfs_fh *,

		   const fmode_t) __must_hold(rcu);



struct nfsd_localio_operations {

	bool (*nfsd_serv_try_get)(struct net *);

	void (*nfsd_serv_put)(struct net *);

	struct nfsd_file *(*nfsd_open_local_fh)(struct net *,

						struct auth_domain *,

						struct rpc_clnt *,

						const struct cred *,

						const struct nfs_fh *,

						const fmode_t);

	void (*nfsd_file_put_local)(struct nfsd_file *);

	struct file *(*nfsd_file_file)(struct nfsd_file *);

} ____cacheline_aligned;



extern void nfsd_localio_ops_init(void);

extern const struct nfsd_localio_operations *nfs_to;



#endif  /* __LINUX_NFSLOCALIO_H */