xref: /openbmc/linux/include/linux/nfs_fs.h (revision 2f0754f2)
1 /* SPDX-License-Identifier: GPL-2.0 */
2 /*
3  *  linux/include/linux/nfs_fs.h
4  *
5  *  Copyright (C) 1992  Rick Sladkey
6  *
7  *  OS-specific nfs filesystem definitions and declarations
8  */
9 #ifndef _LINUX_NFS_FS_H
10 #define _LINUX_NFS_FS_H
11 
12 #include <uapi/linux/nfs_fs.h>
13 
14 
15 /*
16  * Enable dprintk() debugging support for nfs client.
17  */
18 #ifdef CONFIG_NFS_DEBUG
19 # define NFS_DEBUG
20 #endif
21 
22 #include <linux/in.h>
23 #include <linux/mm.h>
24 #include <linux/pagemap.h>
25 #include <linux/rbtree.h>
26 #include <linux/refcount.h>
27 #include <linux/rwsem.h>
28 #include <linux/wait.h>
29 
30 #include <linux/sunrpc/debug.h>
31 #include <linux/sunrpc/auth.h>
32 #include <linux/sunrpc/clnt.h>
33 
34 #include <linux/nfs.h>
35 #include <linux/nfs2.h>
36 #include <linux/nfs3.h>
37 #include <linux/nfs4.h>
38 #include <linux/nfs_xdr.h>
39 #include <linux/nfs_fs_sb.h>
40 
41 #include <linux/mempool.h>
42 
43 /*
44  * These are the default for number of transports to different server IPs
45  */
46 #define NFS_MAX_TRANSPORTS 16
47 
48 /*
49  * These are the default flags for swap requests
50  */
51 #define NFS_RPC_SWAPFLAGS		(RPC_TASK_SWAPPER|RPC_TASK_ROOTCREDS)
52 
53 /*
54  * Size of the NFS directory verifier
55  */
56 #define NFS_DIR_VERIFIER_SIZE		2
57 
58 /*
59  * NFSv3/v4 Access mode cache entry
60  */
61 struct nfs_access_entry {
62 	struct rb_node		rb_node;
63 	struct list_head	lru;
64 	const struct cred *	cred;
65 	__u32			mask;
66 	struct rcu_head		rcu_head;
67 };
68 
69 struct nfs_lock_context {
70 	refcount_t count;
71 	struct list_head list;
72 	struct nfs_open_context *open_context;
73 	fl_owner_t lockowner;
74 	atomic_t io_count;
75 	struct rcu_head	rcu_head;
76 };
77 
78 struct nfs4_state;
79 struct nfs_open_context {
80 	struct nfs_lock_context lock_context;
81 	fl_owner_t flock_owner;
82 	struct dentry *dentry;
83 	const struct cred *cred;
84 	struct rpc_cred __rcu *ll_cred;	/* low-level cred - use to check for expiry */
85 	struct nfs4_state *state;
86 	fmode_t mode;
87 
88 	unsigned long flags;
89 #define NFS_CONTEXT_RESEND_WRITES	(1)
90 #define NFS_CONTEXT_BAD			(2)
91 #define NFS_CONTEXT_UNLOCK	(3)
92 #define NFS_CONTEXT_FILE_OPEN		(4)
93 	int error;
94 
95 	struct list_head list;
96 	struct nfs4_threshold	*mdsthreshold;
97 	struct rcu_head	rcu_head;
98 };
99 
100 struct nfs_open_dir_context {
101 	struct list_head list;
102 	unsigned long attr_gencount;
103 	__be32	verf[NFS_DIR_VERIFIER_SIZE];
104 	__u64 dir_cookie;
105 	__u64 dup_cookie;
106 	pgoff_t page_index;
107 	signed char duped;
108 };
109 
110 /*
111  * NFSv4 delegation
112  */
113 struct nfs_delegation;
114 
115 struct posix_acl;
116 
117 struct nfs4_xattr_cache;
118 
119 /*
120  * nfs fs inode data in memory
121  */
122 struct nfs_inode {
123 	/*
124 	 * The 64bit 'inode number'
125 	 */
126 	__u64 fileid;
127 
128 	/*
129 	 * NFS file handle
130 	 */
131 	struct nfs_fh		fh;
132 
133 	/*
134 	 * Various flags
135 	 */
136 	unsigned long		flags;			/* atomic bit ops */
137 	unsigned long		cache_validity;		/* bit mask */
138 
139 	/*
140 	 * read_cache_jiffies is when we started read-caching this inode.
141 	 * attrtimeo is for how long the cached information is assumed
142 	 * to be valid. A successful attribute revalidation doubles
143 	 * attrtimeo (up to acregmax/acdirmax), a failure resets it to
144 	 * acregmin/acdirmin.
145 	 *
146 	 * We need to revalidate the cached attrs for this inode if
147 	 *
148 	 *	jiffies - read_cache_jiffies >= attrtimeo
149 	 *
150 	 * Please note the comparison is greater than or equal
151 	 * so that zero timeout values can be specified.
152 	 */
153 	unsigned long		read_cache_jiffies;
154 	unsigned long		attrtimeo;
155 	unsigned long		attrtimeo_timestamp;
156 
157 	unsigned long		attr_gencount;
158 
159 	struct rb_root		access_cache;
160 	struct list_head	access_cache_entry_lru;
161 	struct list_head	access_cache_inode_lru;
162 
163 	union {
164 		/* Directory */
165 		struct {
166 			/* "Generation counter" for the attribute cache.
167 			 * This is bumped whenever we update the metadata
168 			 * on the server.
169 			 */
170 			unsigned long	cache_change_attribute;
171 			/*
172 			 * This is the cookie verifier used for NFSv3 readdir
173 			 * operations
174 			 */
175 			__be32		cookieverf[NFS_DIR_VERIFIER_SIZE];
176 			/* Readers: in-flight sillydelete RPC calls */
177 			/* Writers: rmdir */
178 			struct rw_semaphore	rmdir_sem;
179 		};
180 		/* Regular file */
181 		struct {
182 			atomic_long_t	nrequests;
183 			struct nfs_mds_commit_info commit_info;
184 			struct mutex	commit_mutex;
185 		};
186 	};
187 
188 	/* Open contexts for shared mmap writes */
189 	struct list_head	open_files;
190 
191 #if IS_ENABLED(CONFIG_NFS_V4)
192 	struct nfs4_cached_acl	*nfs4_acl;
193         /* NFSv4 state */
194 	struct list_head	open_states;
195 	struct nfs_delegation __rcu *delegation;
196 	struct rw_semaphore	rwsem;
197 
198 	/* pNFS layout information */
199 	struct pnfs_layout_hdr *layout;
200 #endif /* CONFIG_NFS_V4*/
201 	/* how many bytes have been written/read and how many bytes queued up */
202 	__u64 write_io;
203 	__u64 read_io;
204 #ifdef CONFIG_NFS_FSCACHE
205 	struct fscache_cookie	*fscache;
206 #endif
207 	struct inode		vfs_inode;
208 
209 #ifdef CONFIG_NFS_V4_2
210 	struct nfs4_xattr_cache *xattr_cache;
211 #endif
212 };
213 
214 struct nfs4_copy_state {
215 	struct list_head	copies;
216 	struct list_head	src_copies;
217 	nfs4_stateid		stateid;
218 	struct completion	completion;
219 	uint64_t		count;
220 	struct nfs_writeverf	verf;
221 	int			error;
222 	int			flags;
223 	struct nfs4_state	*parent_src_state;
224 	struct nfs4_state	*parent_dst_state;
225 };
226 
227 /*
228  * Access bit flags
229  */
230 #define NFS_ACCESS_READ        0x0001
231 #define NFS_ACCESS_LOOKUP      0x0002
232 #define NFS_ACCESS_MODIFY      0x0004
233 #define NFS_ACCESS_EXTEND      0x0008
234 #define NFS_ACCESS_DELETE      0x0010
235 #define NFS_ACCESS_EXECUTE     0x0020
236 #define NFS_ACCESS_XAREAD      0x0040
237 #define NFS_ACCESS_XAWRITE     0x0080
238 #define NFS_ACCESS_XALIST      0x0100
239 
240 /*
241  * Cache validity bit flags
242  */
243 #define NFS_INO_INVALID_DATA	BIT(1)		/* cached data is invalid */
244 #define NFS_INO_INVALID_ATIME	BIT(2)		/* cached atime is invalid */
245 #define NFS_INO_INVALID_ACCESS	BIT(3)		/* cached access cred invalid */
246 #define NFS_INO_INVALID_ACL	BIT(4)		/* cached acls are invalid */
247 #define NFS_INO_REVAL_PAGECACHE	BIT(5)		/* must revalidate pagecache */
248 #define NFS_INO_REVAL_FORCED	BIT(6)		/* force revalidation ignoring a delegation */
249 #define NFS_INO_INVALID_LABEL	BIT(7)		/* cached label is invalid */
250 #define NFS_INO_INVALID_CHANGE	BIT(8)		/* cached change is invalid */
251 #define NFS_INO_INVALID_CTIME	BIT(9)		/* cached ctime is invalid */
252 #define NFS_INO_INVALID_MTIME	BIT(10)		/* cached mtime is invalid */
253 #define NFS_INO_INVALID_SIZE	BIT(11)		/* cached size is invalid */
254 #define NFS_INO_INVALID_OTHER	BIT(12)		/* other attrs are invalid */
255 #define NFS_INO_DATA_INVAL_DEFER	\
256 				BIT(13)		/* Deferred cache invalidation */
257 #define NFS_INO_INVALID_BLOCKS	BIT(14)         /* cached blocks are invalid */
258 #define NFS_INO_INVALID_XATTR	BIT(15)		/* xattrs are invalid */
259 #define NFS_INO_INVALID_NLINK	BIT(16)		/* cached nlinks is invalid */
260 #define NFS_INO_INVALID_MODE	BIT(17)		/* cached mode is invalid */
261 
262 #define NFS_INO_INVALID_ATTR	(NFS_INO_INVALID_CHANGE \
263 		| NFS_INO_INVALID_CTIME \
264 		| NFS_INO_INVALID_MTIME \
265 		| NFS_INO_INVALID_SIZE \
266 		| NFS_INO_INVALID_NLINK \
267 		| NFS_INO_INVALID_MODE \
268 		| NFS_INO_INVALID_OTHER)	/* inode metadata is invalid */
269 
270 /*
271  * Bit offsets in flags field
272  */
273 #define NFS_INO_ADVISE_RDPLUS	(0)		/* advise readdirplus */
274 #define NFS_INO_STALE		(1)		/* possible stale inode */
275 #define NFS_INO_ACL_LRU_SET	(2)		/* Inode is on the LRU list */
276 #define NFS_INO_INVALIDATING	(3)		/* inode is being invalidated */
277 #define NFS_INO_FSCACHE		(5)		/* inode can be cached by FS-Cache */
278 #define NFS_INO_FORCE_READDIR	(7)		/* force readdirplus */
279 #define NFS_INO_LAYOUTCOMMIT	(9)		/* layoutcommit required */
280 #define NFS_INO_LAYOUTCOMMITTING (10)		/* layoutcommit inflight */
281 #define NFS_INO_LAYOUTSTATS	(11)		/* layoutstats inflight */
282 #define NFS_INO_ODIRECT		(12)		/* I/O setting is O_DIRECT */
283 
284 static inline struct nfs_inode *NFS_I(const struct inode *inode)
285 {
286 	return container_of(inode, struct nfs_inode, vfs_inode);
287 }
288 
289 static inline struct nfs_server *NFS_SB(const struct super_block *s)
290 {
291 	return (struct nfs_server *)(s->s_fs_info);
292 }
293 
294 static inline struct nfs_fh *NFS_FH(const struct inode *inode)
295 {
296 	return &NFS_I(inode)->fh;
297 }
298 
299 static inline struct nfs_server *NFS_SERVER(const struct inode *inode)
300 {
301 	return NFS_SB(inode->i_sb);
302 }
303 
304 static inline struct rpc_clnt *NFS_CLIENT(const struct inode *inode)
305 {
306 	return NFS_SERVER(inode)->client;
307 }
308 
309 static inline const struct nfs_rpc_ops *NFS_PROTO(const struct inode *inode)
310 {
311 	return NFS_SERVER(inode)->nfs_client->rpc_ops;
312 }
313 
314 static inline unsigned NFS_MINATTRTIMEO(const struct inode *inode)
315 {
316 	struct nfs_server *nfss = NFS_SERVER(inode);
317 	return S_ISDIR(inode->i_mode) ? nfss->acdirmin : nfss->acregmin;
318 }
319 
320 static inline unsigned NFS_MAXATTRTIMEO(const struct inode *inode)
321 {
322 	struct nfs_server *nfss = NFS_SERVER(inode);
323 	return S_ISDIR(inode->i_mode) ? nfss->acdirmax : nfss->acregmax;
324 }
325 
326 static inline int NFS_STALE(const struct inode *inode)
327 {
328 	return test_bit(NFS_INO_STALE, &NFS_I(inode)->flags);
329 }
330 
331 static inline struct fscache_cookie *nfs_i_fscache(struct inode *inode)
332 {
333 #ifdef CONFIG_NFS_FSCACHE
334 	return NFS_I(inode)->fscache;
335 #else
336 	return NULL;
337 #endif
338 }
339 
340 static inline __u64 NFS_FILEID(const struct inode *inode)
341 {
342 	return NFS_I(inode)->fileid;
343 }
344 
345 static inline void set_nfs_fileid(struct inode *inode, __u64 fileid)
346 {
347 	NFS_I(inode)->fileid = fileid;
348 }
349 
350 static inline void nfs_mark_for_revalidate(struct inode *inode)
351 {
352 	struct nfs_inode *nfsi = NFS_I(inode);
353 
354 	spin_lock(&inode->i_lock);
355 	nfsi->cache_validity |= NFS_INO_REVAL_PAGECACHE
356 		| NFS_INO_INVALID_ACCESS
357 		| NFS_INO_INVALID_ACL
358 		| NFS_INO_INVALID_CHANGE
359 		| NFS_INO_INVALID_CTIME;
360 	if (S_ISDIR(inode->i_mode))
361 		nfsi->cache_validity |= NFS_INO_INVALID_DATA;
362 	spin_unlock(&inode->i_lock);
363 }
364 
365 static inline int nfs_server_capable(struct inode *inode, int cap)
366 {
367 	return NFS_SERVER(inode)->caps & cap;
368 }
369 
370 /**
371  * nfs_save_change_attribute - Returns the inode attribute change cookie
372  * @dir - pointer to parent directory inode
373  * The "cache change attribute" is updated when we need to revalidate
374  * our dentry cache after a directory was seen to change on the server.
375  */
376 static inline unsigned long nfs_save_change_attribute(struct inode *dir)
377 {
378 	return NFS_I(dir)->cache_change_attribute;
379 }
380 
381 /*
382  * linux/fs/nfs/inode.c
383  */
384 extern int nfs_sync_mapping(struct address_space *mapping);
385 extern void nfs_zap_mapping(struct inode *inode, struct address_space *mapping);
386 extern void nfs_zap_caches(struct inode *);
387 extern void nfs_set_inode_stale(struct inode *inode);
388 extern void nfs_invalidate_atime(struct inode *);
389 extern struct inode *nfs_fhget(struct super_block *, struct nfs_fh *,
390 				struct nfs_fattr *);
391 struct inode *nfs_ilookup(struct super_block *sb, struct nfs_fattr *, struct nfs_fh *);
392 extern int nfs_refresh_inode(struct inode *, struct nfs_fattr *);
393 extern int nfs_post_op_update_inode(struct inode *inode, struct nfs_fattr *fattr);
394 extern int nfs_post_op_update_inode_force_wcc(struct inode *inode, struct nfs_fattr *fattr);
395 extern int nfs_post_op_update_inode_force_wcc_locked(struct inode *inode, struct nfs_fattr *fattr);
396 extern int nfs_getattr(struct user_namespace *, const struct path *,
397 		       struct kstat *, u32, unsigned int);
398 extern void nfs_access_add_cache(struct inode *, struct nfs_access_entry *);
399 extern void nfs_access_set_mask(struct nfs_access_entry *, u32);
400 extern int nfs_permission(struct user_namespace *, struct inode *, int);
401 extern int nfs_open(struct inode *, struct file *);
402 extern int nfs_attribute_cache_expired(struct inode *inode);
403 extern int nfs_revalidate_inode(struct inode *inode, unsigned long flags);
404 extern int __nfs_revalidate_inode(struct nfs_server *, struct inode *);
405 extern int nfs_clear_invalid_mapping(struct address_space *mapping);
406 extern bool nfs_mapping_need_revalidate_inode(struct inode *inode);
407 extern int nfs_revalidate_mapping(struct inode *inode, struct address_space *mapping);
408 extern int nfs_revalidate_mapping_rcu(struct inode *inode);
409 extern int nfs_setattr(struct user_namespace *, struct dentry *, struct iattr *);
410 extern void nfs_setattr_update_inode(struct inode *inode, struct iattr *attr, struct nfs_fattr *);
411 extern void nfs_setsecurity(struct inode *inode, struct nfs_fattr *fattr);
412 extern struct nfs_open_context *get_nfs_open_context(struct nfs_open_context *ctx);
413 extern void put_nfs_open_context(struct nfs_open_context *ctx);
414 extern struct nfs_open_context *nfs_find_open_context(struct inode *inode, const struct cred *cred, fmode_t mode);
415 extern struct nfs_open_context *alloc_nfs_open_context(struct dentry *dentry, fmode_t f_mode, struct file *filp);
416 extern void nfs_inode_attach_open_context(struct nfs_open_context *ctx);
417 extern void nfs_file_set_open_context(struct file *filp, struct nfs_open_context *ctx);
418 extern void nfs_file_clear_open_context(struct file *flip);
419 extern struct nfs_lock_context *nfs_get_lock_context(struct nfs_open_context *ctx);
420 extern void nfs_put_lock_context(struct nfs_lock_context *l_ctx);
421 extern u64 nfs_compat_user_ino64(u64 fileid);
422 extern void nfs_fattr_init(struct nfs_fattr *fattr);
423 extern void nfs_fattr_set_barrier(struct nfs_fattr *fattr);
424 extern unsigned long nfs_inc_attr_generation_counter(void);
425 
426 extern struct nfs_fattr *nfs_alloc_fattr(void);
427 extern struct nfs_fattr *nfs_alloc_fattr_with_label(struct nfs_server *server);
428 
429 static inline void nfs4_label_free(struct nfs4_label *label)
430 {
431 #ifdef CONFIG_NFS_V4_SECURITY_LABEL
432 	if (label) {
433 		kfree(label->label);
434 		kfree(label);
435 	}
436 #endif
437 }
438 
439 static inline void nfs_free_fattr(const struct nfs_fattr *fattr)
440 {
441 	if (fattr)
442 		nfs4_label_free(fattr->label);
443 	kfree(fattr);
444 }
445 
446 extern struct nfs_fh *nfs_alloc_fhandle(void);
447 
448 static inline void nfs_free_fhandle(const struct nfs_fh *fh)
449 {
450 	kfree(fh);
451 }
452 
453 #ifdef NFS_DEBUG
454 extern u32 _nfs_display_fhandle_hash(const struct nfs_fh *fh);
455 static inline u32 nfs_display_fhandle_hash(const struct nfs_fh *fh)
456 {
457 	return _nfs_display_fhandle_hash(fh);
458 }
459 extern void _nfs_display_fhandle(const struct nfs_fh *fh, const char *caption);
460 #define nfs_display_fhandle(fh, caption)			\
461 	do {							\
462 		if (unlikely(nfs_debug & NFSDBG_FACILITY))	\
463 			_nfs_display_fhandle(fh, caption);	\
464 	} while (0)
465 #else
466 static inline u32 nfs_display_fhandle_hash(const struct nfs_fh *fh)
467 {
468 	return 0;
469 }
470 static inline void nfs_display_fhandle(const struct nfs_fh *fh,
471 				       const char *caption)
472 {
473 }
474 #endif
475 
476 /*
477  * linux/fs/nfs/nfsroot.c
478  */
479 extern int  nfs_root_data(char **root_device, char **root_data); /*__init*/
480 /* linux/net/ipv4/ipconfig.c: trims ip addr off front of name, too. */
481 extern __be32 root_nfs_parse_addr(char *name); /*__init*/
482 
483 /*
484  * linux/fs/nfs/file.c
485  */
486 extern const struct file_operations nfs_file_operations;
487 #if IS_ENABLED(CONFIG_NFS_V4)
488 extern const struct file_operations nfs4_file_operations;
489 #endif /* CONFIG_NFS_V4 */
490 extern const struct address_space_operations nfs_file_aops;
491 extern const struct address_space_operations nfs_dir_aops;
492 
493 static inline struct nfs_open_context *nfs_file_open_context(struct file *filp)
494 {
495 	return filp->private_data;
496 }
497 
498 static inline const struct cred *nfs_file_cred(struct file *file)
499 {
500 	if (file != NULL) {
501 		struct nfs_open_context *ctx =
502 			nfs_file_open_context(file);
503 		if (ctx)
504 			return ctx->cred;
505 	}
506 	return NULL;
507 }
508 
509 /*
510  * linux/fs/nfs/direct.c
511  */
512 extern ssize_t nfs_direct_IO(struct kiocb *, struct iov_iter *);
513 extern ssize_t nfs_file_direct_read(struct kiocb *iocb,
514 			struct iov_iter *iter);
515 extern ssize_t nfs_file_direct_write(struct kiocb *iocb,
516 			struct iov_iter *iter);
517 
518 /*
519  * linux/fs/nfs/dir.c
520  */
521 extern const struct file_operations nfs_dir_operations;
522 extern const struct dentry_operations nfs_dentry_operations;
523 
524 extern void nfs_force_lookup_revalidate(struct inode *dir);
525 extern void nfs_set_verifier(struct dentry * dentry, unsigned long verf);
526 #if IS_ENABLED(CONFIG_NFS_V4)
527 extern void nfs_clear_verifier_delegated(struct inode *inode);
528 #endif /* IS_ENABLED(CONFIG_NFS_V4) */
529 extern struct dentry *nfs_add_or_obtain(struct dentry *dentry,
530 			struct nfs_fh *fh, struct nfs_fattr *fattr);
531 extern int nfs_instantiate(struct dentry *dentry, struct nfs_fh *fh,
532 			struct nfs_fattr *fattr);
533 extern int nfs_may_open(struct inode *inode, const struct cred *cred, int openflags);
534 extern void nfs_access_zap_cache(struct inode *inode);
535 extern int nfs_access_get_cached(struct inode *inode, const struct cred *cred, struct nfs_access_entry *res,
536 				 bool may_block);
537 
538 /*
539  * linux/fs/nfs/symlink.c
540  */
541 extern const struct inode_operations nfs_symlink_inode_operations;
542 
543 /*
544  * linux/fs/nfs/sysctl.c
545  */
546 #ifdef CONFIG_SYSCTL
547 extern int nfs_register_sysctl(void);
548 extern void nfs_unregister_sysctl(void);
549 #else
550 #define nfs_register_sysctl() 0
551 #define nfs_unregister_sysctl() do { } while(0)
552 #endif
553 
554 /*
555  * linux/fs/nfs/namespace.c
556  */
557 extern const struct inode_operations nfs_mountpoint_inode_operations;
558 extern const struct inode_operations nfs_referral_inode_operations;
559 extern int nfs_mountpoint_expiry_timeout;
560 extern void nfs_release_automount_timer(void);
561 
562 /*
563  * linux/fs/nfs/unlink.c
564  */
565 extern void nfs_complete_unlink(struct dentry *dentry, struct inode *);
566 
567 /*
568  * linux/fs/nfs/write.c
569  */
570 extern int  nfs_congestion_kb;
571 extern int  nfs_writepage(struct page *page, struct writeback_control *wbc);
572 extern int  nfs_writepages(struct address_space *, struct writeback_control *);
573 extern int  nfs_flush_incompatible(struct file *file, struct page *page);
574 extern int  nfs_updatepage(struct file *, struct page *, unsigned int, unsigned int);
575 
576 /*
577  * Try to write back everything synchronously (but check the
578  * return value!)
579  */
580 extern int nfs_sync_inode(struct inode *inode);
581 extern int nfs_wb_all(struct inode *inode);
582 extern int nfs_wb_page(struct inode *inode, struct page *page);
583 extern int nfs_wb_page_cancel(struct inode *inode, struct page* page);
584 extern int  nfs_commit_inode(struct inode *, int);
585 extern struct nfs_commit_data *nfs_commitdata_alloc(bool never_fail);
586 extern void nfs_commit_free(struct nfs_commit_data *data);
587 bool nfs_commit_end(struct nfs_mds_commit_info *cinfo);
588 
589 static inline int
590 nfs_have_writebacks(struct inode *inode)
591 {
592 	if (S_ISREG(inode->i_mode))
593 		return atomic_long_read(&NFS_I(inode)->nrequests) != 0;
594 	return 0;
595 }
596 
597 /*
598  * linux/fs/nfs/read.c
599  */
600 extern int  nfs_readpage(struct file *, struct page *);
601 extern int  nfs_readpages(struct file *, struct address_space *,
602 		struct list_head *, unsigned);
603 
604 /*
605  * inline functions
606  */
607 
608 static inline loff_t nfs_size_to_loff_t(__u64 size)
609 {
610 	return min_t(u64, size, OFFSET_MAX);
611 }
612 
613 static inline ino_t
614 nfs_fileid_to_ino_t(u64 fileid)
615 {
616 	ino_t ino = (ino_t) fileid;
617 	if (sizeof(ino_t) < sizeof(u64))
618 		ino ^= fileid >> (sizeof(u64)-sizeof(ino_t)) * 8;
619 	return ino;
620 }
621 
622 #define NFS_JUKEBOX_RETRY_TIME (5 * HZ)
623 
624 
625 # undef ifdebug
626 # ifdef NFS_DEBUG
627 #  define ifdebug(fac)		if (unlikely(nfs_debug & NFSDBG_##fac))
628 #  define NFS_IFDEBUG(x)	x
629 # else
630 #  define ifdebug(fac)		if (0)
631 #  define NFS_IFDEBUG(x)
632 # endif
633 #endif
634