xref: /openbmc/linux/include/linux/nfs_fs.h (revision 6b342707)
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 	kuid_t			fsuid;
65 	kgid_t			fsgid;
66 	struct group_info	*group_info;
67 	__u32			mask;
68 	struct rcu_head		rcu_head;
69 };
70 
71 struct nfs_lock_context {
72 	refcount_t count;
73 	struct list_head list;
74 	struct nfs_open_context *open_context;
75 	fl_owner_t lockowner;
76 	atomic_t io_count;
77 	struct rcu_head	rcu_head;
78 };
79 
80 struct nfs4_state;
81 struct nfs_open_context {
82 	struct nfs_lock_context lock_context;
83 	fl_owner_t flock_owner;
84 	struct dentry *dentry;
85 	const struct cred *cred;
86 	struct rpc_cred __rcu *ll_cred;	/* low-level cred - use to check for expiry */
87 	struct nfs4_state *state;
88 	fmode_t mode;
89 
90 	unsigned long flags;
91 #define NFS_CONTEXT_RESEND_WRITES	(1)
92 #define NFS_CONTEXT_BAD			(2)
93 #define NFS_CONTEXT_UNLOCK	(3)
94 #define NFS_CONTEXT_FILE_OPEN		(4)
95 	int error;
96 
97 	struct list_head list;
98 	struct nfs4_threshold	*mdsthreshold;
99 	struct rcu_head	rcu_head;
100 };
101 
102 struct nfs_open_dir_context {
103 	struct list_head list;
104 	unsigned long attr_gencount;
105 	__be32	verf[NFS_DIR_VERIFIER_SIZE];
106 	__u64 dir_cookie;
107 	__u64 dup_cookie;
108 	pgoff_t page_index;
109 	signed char duped;
110 	bool eof;
111 };
112 
113 /*
114  * NFSv4 delegation
115  */
116 struct nfs_delegation;
117 
118 struct posix_acl;
119 
120 struct nfs4_xattr_cache;
121 
122 /*
123  * nfs fs inode data in memory
124  */
125 struct nfs_inode {
126 	/*
127 	 * The 64bit 'inode number'
128 	 */
129 	__u64 fileid;
130 
131 	/*
132 	 * NFS file handle
133 	 */
134 	struct nfs_fh		fh;
135 
136 	/*
137 	 * Various flags
138 	 */
139 	unsigned long		flags;			/* atomic bit ops */
140 	unsigned long		cache_validity;		/* bit mask */
141 
142 	/*
143 	 * read_cache_jiffies is when we started read-caching this inode.
144 	 * attrtimeo is for how long the cached information is assumed
145 	 * to be valid. A successful attribute revalidation doubles
146 	 * attrtimeo (up to acregmax/acdirmax), a failure resets it to
147 	 * acregmin/acdirmin.
148 	 *
149 	 * We need to revalidate the cached attrs for this inode if
150 	 *
151 	 *	jiffies - read_cache_jiffies >= attrtimeo
152 	 *
153 	 * Please note the comparison is greater than or equal
154 	 * so that zero timeout values can be specified.
155 	 */
156 	unsigned long		read_cache_jiffies;
157 	unsigned long		attrtimeo;
158 	unsigned long		attrtimeo_timestamp;
159 
160 	unsigned long		attr_gencount;
161 
162 	struct rb_root		access_cache;
163 	struct list_head	access_cache_entry_lru;
164 	struct list_head	access_cache_inode_lru;
165 
166 	union {
167 		/* Directory */
168 		struct {
169 			/* "Generation counter" for the attribute cache.
170 			 * This is bumped whenever we update the metadata
171 			 * on the server.
172 			 */
173 			unsigned long	cache_change_attribute;
174 			/*
175 			 * This is the cookie verifier used for NFSv3 readdir
176 			 * operations
177 			 */
178 			__be32		cookieverf[NFS_DIR_VERIFIER_SIZE];
179 			/* Readers: in-flight sillydelete RPC calls */
180 			/* Writers: rmdir */
181 			struct rw_semaphore	rmdir_sem;
182 		};
183 		/* Regular file */
184 		struct {
185 			atomic_long_t	nrequests;
186 			struct nfs_mds_commit_info commit_info;
187 			struct mutex	commit_mutex;
188 		};
189 	};
190 
191 	/* Open contexts for shared mmap writes */
192 	struct list_head	open_files;
193 
194 #if IS_ENABLED(CONFIG_NFS_V4)
195 	struct nfs4_cached_acl	*nfs4_acl;
196         /* NFSv4 state */
197 	struct list_head	open_states;
198 	struct nfs_delegation __rcu *delegation;
199 	struct rw_semaphore	rwsem;
200 
201 	/* pNFS layout information */
202 	struct pnfs_layout_hdr *layout;
203 #endif /* CONFIG_NFS_V4*/
204 	/* how many bytes have been written/read and how many bytes queued up */
205 	__u64 write_io;
206 	__u64 read_io;
207 #ifdef CONFIG_NFS_FSCACHE
208 	struct fscache_cookie	*fscache;
209 #endif
210 	struct inode		vfs_inode;
211 
212 #ifdef CONFIG_NFS_V4_2
213 	struct nfs4_xattr_cache *xattr_cache;
214 #endif
215 };
216 
217 struct nfs4_copy_state {
218 	struct list_head	copies;
219 	struct list_head	src_copies;
220 	nfs4_stateid		stateid;
221 	struct completion	completion;
222 	uint64_t		count;
223 	struct nfs_writeverf	verf;
224 	int			error;
225 	int			flags;
226 	struct nfs4_state	*parent_src_state;
227 	struct nfs4_state	*parent_dst_state;
228 };
229 
230 /*
231  * Access bit flags
232  */
233 #define NFS_ACCESS_READ        0x0001
234 #define NFS_ACCESS_LOOKUP      0x0002
235 #define NFS_ACCESS_MODIFY      0x0004
236 #define NFS_ACCESS_EXTEND      0x0008
237 #define NFS_ACCESS_DELETE      0x0010
238 #define NFS_ACCESS_EXECUTE     0x0020
239 #define NFS_ACCESS_XAREAD      0x0040
240 #define NFS_ACCESS_XAWRITE     0x0080
241 #define NFS_ACCESS_XALIST      0x0100
242 
243 /*
244  * Cache validity bit flags
245  */
246 #define NFS_INO_INVALID_DATA	BIT(1)		/* cached data is invalid */
247 #define NFS_INO_INVALID_ATIME	BIT(2)		/* cached atime is invalid */
248 #define NFS_INO_INVALID_ACCESS	BIT(3)		/* cached access cred invalid */
249 #define NFS_INO_INVALID_ACL	BIT(4)		/* cached acls are invalid */
250 #define NFS_INO_REVAL_PAGECACHE	BIT(5)		/* must revalidate pagecache */
251 #define NFS_INO_REVAL_FORCED	BIT(6)		/* force revalidation ignoring a delegation */
252 #define NFS_INO_INVALID_LABEL	BIT(7)		/* cached label is invalid */
253 #define NFS_INO_INVALID_CHANGE	BIT(8)		/* cached change is invalid */
254 #define NFS_INO_INVALID_CTIME	BIT(9)		/* cached ctime is invalid */
255 #define NFS_INO_INVALID_MTIME	BIT(10)		/* cached mtime is invalid */
256 #define NFS_INO_INVALID_SIZE	BIT(11)		/* cached size is invalid */
257 #define NFS_INO_INVALID_OTHER	BIT(12)		/* other attrs are invalid */
258 #define NFS_INO_DATA_INVAL_DEFER	\
259 				BIT(13)		/* Deferred cache invalidation */
260 #define NFS_INO_INVALID_BLOCKS	BIT(14)         /* cached blocks are invalid */
261 #define NFS_INO_INVALID_XATTR	BIT(15)		/* xattrs are invalid */
262 #define NFS_INO_INVALID_NLINK	BIT(16)		/* cached nlinks is invalid */
263 #define NFS_INO_INVALID_MODE	BIT(17)		/* cached mode is invalid */
264 
265 #define NFS_INO_INVALID_ATTR	(NFS_INO_INVALID_CHANGE \
266 		| NFS_INO_INVALID_CTIME \
267 		| NFS_INO_INVALID_MTIME \
268 		| NFS_INO_INVALID_SIZE \
269 		| NFS_INO_INVALID_NLINK \
270 		| NFS_INO_INVALID_MODE \
271 		| NFS_INO_INVALID_OTHER)	/* inode metadata is invalid */
272 
273 /*
274  * Bit offsets in flags field
275  */
276 #define NFS_INO_ADVISE_RDPLUS	(0)		/* advise readdirplus */
277 #define NFS_INO_STALE		(1)		/* possible stale inode */
278 #define NFS_INO_ACL_LRU_SET	(2)		/* Inode is on the LRU list */
279 #define NFS_INO_INVALIDATING	(3)		/* inode is being invalidated */
280 #define NFS_INO_FSCACHE		(5)		/* inode can be cached by FS-Cache */
281 #define NFS_INO_FORCE_READDIR	(7)		/* force readdirplus */
282 #define NFS_INO_LAYOUTCOMMIT	(9)		/* layoutcommit required */
283 #define NFS_INO_LAYOUTCOMMITTING (10)		/* layoutcommit inflight */
284 #define NFS_INO_LAYOUTSTATS	(11)		/* layoutstats inflight */
285 #define NFS_INO_ODIRECT		(12)		/* I/O setting is O_DIRECT */
286 
287 static inline struct nfs_inode *NFS_I(const struct inode *inode)
288 {
289 	return container_of(inode, struct nfs_inode, vfs_inode);
290 }
291 
292 static inline struct nfs_server *NFS_SB(const struct super_block *s)
293 {
294 	return (struct nfs_server *)(s->s_fs_info);
295 }
296 
297 static inline struct nfs_fh *NFS_FH(const struct inode *inode)
298 {
299 	return &NFS_I(inode)->fh;
300 }
301 
302 static inline struct nfs_server *NFS_SERVER(const struct inode *inode)
303 {
304 	return NFS_SB(inode->i_sb);
305 }
306 
307 static inline struct rpc_clnt *NFS_CLIENT(const struct inode *inode)
308 {
309 	return NFS_SERVER(inode)->client;
310 }
311 
312 static inline const struct nfs_rpc_ops *NFS_PROTO(const struct inode *inode)
313 {
314 	return NFS_SERVER(inode)->nfs_client->rpc_ops;
315 }
316 
317 static inline unsigned NFS_MINATTRTIMEO(const struct inode *inode)
318 {
319 	struct nfs_server *nfss = NFS_SERVER(inode);
320 	return S_ISDIR(inode->i_mode) ? nfss->acdirmin : nfss->acregmin;
321 }
322 
323 static inline unsigned NFS_MAXATTRTIMEO(const struct inode *inode)
324 {
325 	struct nfs_server *nfss = NFS_SERVER(inode);
326 	return S_ISDIR(inode->i_mode) ? nfss->acdirmax : nfss->acregmax;
327 }
328 
329 static inline int NFS_STALE(const struct inode *inode)
330 {
331 	return test_bit(NFS_INO_STALE, &NFS_I(inode)->flags);
332 }
333 
334 static inline struct fscache_cookie *nfs_i_fscache(struct inode *inode)
335 {
336 #ifdef CONFIG_NFS_FSCACHE
337 	return NFS_I(inode)->fscache;
338 #else
339 	return NULL;
340 #endif
341 }
342 
343 static inline __u64 NFS_FILEID(const struct inode *inode)
344 {
345 	return NFS_I(inode)->fileid;
346 }
347 
348 static inline void set_nfs_fileid(struct inode *inode, __u64 fileid)
349 {
350 	NFS_I(inode)->fileid = fileid;
351 }
352 
353 static inline void nfs_mark_for_revalidate(struct inode *inode)
354 {
355 	struct nfs_inode *nfsi = NFS_I(inode);
356 
357 	spin_lock(&inode->i_lock);
358 	nfsi->cache_validity |= NFS_INO_REVAL_PAGECACHE
359 		| NFS_INO_INVALID_ACCESS
360 		| NFS_INO_INVALID_ACL
361 		| NFS_INO_INVALID_CHANGE
362 		| NFS_INO_INVALID_CTIME;
363 	if (S_ISDIR(inode->i_mode))
364 		nfsi->cache_validity |= NFS_INO_INVALID_DATA;
365 	spin_unlock(&inode->i_lock);
366 }
367 
368 static inline int nfs_server_capable(struct inode *inode, int cap)
369 {
370 	return NFS_SERVER(inode)->caps & cap;
371 }
372 
373 /**
374  * nfs_save_change_attribute - Returns the inode attribute change cookie
375  * @dir - pointer to parent directory inode
376  * The "cache change attribute" is updated when we need to revalidate
377  * our dentry cache after a directory was seen to change on the server.
378  */
379 static inline unsigned long nfs_save_change_attribute(struct inode *dir)
380 {
381 	return NFS_I(dir)->cache_change_attribute;
382 }
383 
384 /*
385  * linux/fs/nfs/inode.c
386  */
387 extern int nfs_sync_mapping(struct address_space *mapping);
388 extern void nfs_zap_mapping(struct inode *inode, struct address_space *mapping);
389 extern void nfs_zap_caches(struct inode *);
390 extern void nfs_set_inode_stale(struct inode *inode);
391 extern void nfs_invalidate_atime(struct inode *);
392 extern struct inode *nfs_fhget(struct super_block *, struct nfs_fh *,
393 				struct nfs_fattr *);
394 struct inode *nfs_ilookup(struct super_block *sb, struct nfs_fattr *, struct nfs_fh *);
395 extern int nfs_refresh_inode(struct inode *, struct nfs_fattr *);
396 extern int nfs_post_op_update_inode(struct inode *inode, struct nfs_fattr *fattr);
397 extern int nfs_post_op_update_inode_force_wcc(struct inode *inode, struct nfs_fattr *fattr);
398 extern int nfs_post_op_update_inode_force_wcc_locked(struct inode *inode, struct nfs_fattr *fattr);
399 extern int nfs_getattr(struct user_namespace *, const struct path *,
400 		       struct kstat *, u32, unsigned int);
401 extern void nfs_access_add_cache(struct inode *, struct nfs_access_entry *, const struct cred *);
402 extern void nfs_access_set_mask(struct nfs_access_entry *, u32);
403 extern int nfs_permission(struct user_namespace *, struct inode *, int);
404 extern int nfs_open(struct inode *, struct file *);
405 extern int nfs_attribute_cache_expired(struct inode *inode);
406 extern int nfs_revalidate_inode(struct inode *inode, unsigned long flags);
407 extern int __nfs_revalidate_inode(struct nfs_server *, struct inode *);
408 extern int nfs_clear_invalid_mapping(struct address_space *mapping);
409 extern bool nfs_mapping_need_revalidate_inode(struct inode *inode);
410 extern int nfs_revalidate_mapping(struct inode *inode, struct address_space *mapping);
411 extern int nfs_revalidate_mapping_rcu(struct inode *inode);
412 extern int nfs_setattr(struct user_namespace *, struct dentry *, struct iattr *);
413 extern void nfs_setattr_update_inode(struct inode *inode, struct iattr *attr, struct nfs_fattr *);
414 extern void nfs_setsecurity(struct inode *inode, struct nfs_fattr *fattr);
415 extern struct nfs_open_context *get_nfs_open_context(struct nfs_open_context *ctx);
416 extern void put_nfs_open_context(struct nfs_open_context *ctx);
417 extern struct nfs_open_context *nfs_find_open_context(struct inode *inode, const struct cred *cred, fmode_t mode);
418 extern struct nfs_open_context *alloc_nfs_open_context(struct dentry *dentry, fmode_t f_mode, struct file *filp);
419 extern void nfs_inode_attach_open_context(struct nfs_open_context *ctx);
420 extern void nfs_file_set_open_context(struct file *filp, struct nfs_open_context *ctx);
421 extern void nfs_file_clear_open_context(struct file *flip);
422 extern struct nfs_lock_context *nfs_get_lock_context(struct nfs_open_context *ctx);
423 extern void nfs_put_lock_context(struct nfs_lock_context *l_ctx);
424 extern u64 nfs_compat_user_ino64(u64 fileid);
425 extern void nfs_fattr_init(struct nfs_fattr *fattr);
426 extern void nfs_fattr_set_barrier(struct nfs_fattr *fattr);
427 extern unsigned long nfs_inc_attr_generation_counter(void);
428 
429 extern struct nfs_fattr *nfs_alloc_fattr(void);
430 extern struct nfs_fattr *nfs_alloc_fattr_with_label(struct nfs_server *server);
431 
432 static inline void nfs4_label_free(struct nfs4_label *label)
433 {
434 #ifdef CONFIG_NFS_V4_SECURITY_LABEL
435 	if (label) {
436 		kfree(label->label);
437 		kfree(label);
438 	}
439 #endif
440 }
441 
442 static inline void nfs_free_fattr(const struct nfs_fattr *fattr)
443 {
444 	if (fattr)
445 		nfs4_label_free(fattr->label);
446 	kfree(fattr);
447 }
448 
449 extern struct nfs_fh *nfs_alloc_fhandle(void);
450 
451 static inline void nfs_free_fhandle(const struct nfs_fh *fh)
452 {
453 	kfree(fh);
454 }
455 
456 #ifdef NFS_DEBUG
457 extern u32 _nfs_display_fhandle_hash(const struct nfs_fh *fh);
458 static inline u32 nfs_display_fhandle_hash(const struct nfs_fh *fh)
459 {
460 	return _nfs_display_fhandle_hash(fh);
461 }
462 extern void _nfs_display_fhandle(const struct nfs_fh *fh, const char *caption);
463 #define nfs_display_fhandle(fh, caption)			\
464 	do {							\
465 		if (unlikely(nfs_debug & NFSDBG_FACILITY))	\
466 			_nfs_display_fhandle(fh, caption);	\
467 	} while (0)
468 #else
469 static inline u32 nfs_display_fhandle_hash(const struct nfs_fh *fh)
470 {
471 	return 0;
472 }
473 static inline void nfs_display_fhandle(const struct nfs_fh *fh,
474 				       const char *caption)
475 {
476 }
477 #endif
478 
479 /*
480  * linux/fs/nfs/nfsroot.c
481  */
482 extern int  nfs_root_data(char **root_device, char **root_data); /*__init*/
483 /* linux/net/ipv4/ipconfig.c: trims ip addr off front of name, too. */
484 extern __be32 root_nfs_parse_addr(char *name); /*__init*/
485 
486 /*
487  * linux/fs/nfs/file.c
488  */
489 extern const struct file_operations nfs_file_operations;
490 #if IS_ENABLED(CONFIG_NFS_V4)
491 extern const struct file_operations nfs4_file_operations;
492 #endif /* CONFIG_NFS_V4 */
493 extern const struct address_space_operations nfs_file_aops;
494 extern const struct address_space_operations nfs_dir_aops;
495 
496 static inline struct nfs_open_context *nfs_file_open_context(struct file *filp)
497 {
498 	return filp->private_data;
499 }
500 
501 static inline const struct cred *nfs_file_cred(struct file *file)
502 {
503 	if (file != NULL) {
504 		struct nfs_open_context *ctx =
505 			nfs_file_open_context(file);
506 		if (ctx)
507 			return ctx->cred;
508 	}
509 	return NULL;
510 }
511 
512 /*
513  * linux/fs/nfs/direct.c
514  */
515 extern ssize_t nfs_direct_IO(struct kiocb *, struct iov_iter *);
516 extern ssize_t nfs_file_direct_read(struct kiocb *iocb,
517 			struct iov_iter *iter);
518 extern ssize_t nfs_file_direct_write(struct kiocb *iocb,
519 			struct iov_iter *iter);
520 
521 /*
522  * linux/fs/nfs/dir.c
523  */
524 extern const struct file_operations nfs_dir_operations;
525 extern const struct dentry_operations nfs_dentry_operations;
526 
527 extern void nfs_force_lookup_revalidate(struct inode *dir);
528 extern void nfs_set_verifier(struct dentry * dentry, unsigned long verf);
529 #if IS_ENABLED(CONFIG_NFS_V4)
530 extern void nfs_clear_verifier_delegated(struct inode *inode);
531 #endif /* IS_ENABLED(CONFIG_NFS_V4) */
532 extern struct dentry *nfs_add_or_obtain(struct dentry *dentry,
533 			struct nfs_fh *fh, struct nfs_fattr *fattr);
534 extern int nfs_instantiate(struct dentry *dentry, struct nfs_fh *fh,
535 			struct nfs_fattr *fattr);
536 extern int nfs_may_open(struct inode *inode, const struct cred *cred, int openflags);
537 extern void nfs_access_zap_cache(struct inode *inode);
538 extern int nfs_access_get_cached(struct inode *inode, const struct cred *cred,
539 				 u32 *mask, bool may_block);
540 
541 /*
542  * linux/fs/nfs/symlink.c
543  */
544 extern const struct inode_operations nfs_symlink_inode_operations;
545 
546 /*
547  * linux/fs/nfs/sysctl.c
548  */
549 #ifdef CONFIG_SYSCTL
550 extern int nfs_register_sysctl(void);
551 extern void nfs_unregister_sysctl(void);
552 #else
553 #define nfs_register_sysctl() 0
554 #define nfs_unregister_sysctl() do { } while(0)
555 #endif
556 
557 /*
558  * linux/fs/nfs/namespace.c
559  */
560 extern const struct inode_operations nfs_mountpoint_inode_operations;
561 extern const struct inode_operations nfs_referral_inode_operations;
562 extern int nfs_mountpoint_expiry_timeout;
563 extern void nfs_release_automount_timer(void);
564 
565 /*
566  * linux/fs/nfs/unlink.c
567  */
568 extern void nfs_complete_unlink(struct dentry *dentry, struct inode *);
569 
570 /*
571  * linux/fs/nfs/write.c
572  */
573 extern int  nfs_congestion_kb;
574 extern int  nfs_writepage(struct page *page, struct writeback_control *wbc);
575 extern int  nfs_writepages(struct address_space *, struct writeback_control *);
576 extern int  nfs_flush_incompatible(struct file *file, struct page *page);
577 extern int  nfs_updatepage(struct file *, struct page *, unsigned int, unsigned int);
578 
579 /*
580  * Try to write back everything synchronously (but check the
581  * return value!)
582  */
583 extern int nfs_sync_inode(struct inode *inode);
584 extern int nfs_wb_all(struct inode *inode);
585 extern int nfs_wb_page(struct inode *inode, struct page *page);
586 extern int nfs_wb_page_cancel(struct inode *inode, struct page* page);
587 extern int  nfs_commit_inode(struct inode *, int);
588 extern struct nfs_commit_data *nfs_commitdata_alloc(bool never_fail);
589 extern void nfs_commit_free(struct nfs_commit_data *data);
590 bool nfs_commit_end(struct nfs_mds_commit_info *cinfo);
591 
592 static inline int
593 nfs_have_writebacks(struct inode *inode)
594 {
595 	if (S_ISREG(inode->i_mode))
596 		return atomic_long_read(&NFS_I(inode)->nrequests) != 0;
597 	return 0;
598 }
599 
600 /*
601  * linux/fs/nfs/read.c
602  */
603 extern int  nfs_readpage(struct file *, struct page *);
604 extern int  nfs_readpages(struct file *, struct address_space *,
605 		struct list_head *, unsigned);
606 
607 /*
608  * inline functions
609  */
610 
611 static inline loff_t nfs_size_to_loff_t(__u64 size)
612 {
613 	return min_t(u64, size, OFFSET_MAX);
614 }
615 
616 static inline ino_t
617 nfs_fileid_to_ino_t(u64 fileid)
618 {
619 	ino_t ino = (ino_t) fileid;
620 	if (sizeof(ino_t) < sizeof(u64))
621 		ino ^= fileid >> (sizeof(u64)-sizeof(ino_t)) * 8;
622 	return ino;
623 }
624 
625 #define NFS_JUKEBOX_RETRY_TIME (5 * HZ)
626 
627 
628 # undef ifdebug
629 # ifdef NFS_DEBUG
630 #  define ifdebug(fac)		if (unlikely(nfs_debug & NFSDBG_##fac))
631 #  define NFS_IFDEBUG(x)	x
632 # else
633 #  define ifdebug(fac)		if (0)
634 #  define NFS_IFDEBUG(x)
635 # endif
636 #endif
637