xref: /openbmc/linux/include/linux/nfs_fs.h (revision 3e5f1ff7e4f297b928fb579fa1e8ec65a400162e)
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 };
111 
112 /*
113  * NFSv4 delegation
114  */
115 struct nfs_delegation;
116 
117 struct posix_acl;
118 
119 struct nfs4_xattr_cache;
120 
121 /*
122  * nfs fs inode data in memory
123  */
124 struct nfs_inode {
125 	/*
126 	 * The 64bit 'inode number'
127 	 */
128 	__u64 fileid;
129 
130 	/*
131 	 * NFS file handle
132 	 */
133 	struct nfs_fh		fh;
134 
135 	/*
136 	 * Various flags
137 	 */
138 	unsigned long		flags;			/* atomic bit ops */
139 	unsigned long		cache_validity;		/* bit mask */
140 
141 	/*
142 	 * read_cache_jiffies is when we started read-caching this inode.
143 	 * attrtimeo is for how long the cached information is assumed
144 	 * to be valid. A successful attribute revalidation doubles
145 	 * attrtimeo (up to acregmax/acdirmax), a failure resets it to
146 	 * acregmin/acdirmin.
147 	 *
148 	 * We need to revalidate the cached attrs for this inode if
149 	 *
150 	 *	jiffies - read_cache_jiffies >= attrtimeo
151 	 *
152 	 * Please note the comparison is greater than or equal
153 	 * so that zero timeout values can be specified.
154 	 */
155 	unsigned long		read_cache_jiffies;
156 	unsigned long		attrtimeo;
157 	unsigned long		attrtimeo_timestamp;
158 
159 	unsigned long		attr_gencount;
160 
161 	struct rb_root		access_cache;
162 	struct list_head	access_cache_entry_lru;
163 	struct list_head	access_cache_inode_lru;
164 
165 	union {
166 		/* Directory */
167 		struct {
168 			/* "Generation counter" for the attribute cache.
169 			 * This is bumped whenever we update the metadata
170 			 * on the server.
171 			 */
172 			unsigned long	cache_change_attribute;
173 			/*
174 			 * This is the cookie verifier used for NFSv3 readdir
175 			 * operations
176 			 */
177 			__be32		cookieverf[NFS_DIR_VERIFIER_SIZE];
178 			/* Readers: in-flight sillydelete RPC calls */
179 			/* Writers: rmdir */
180 			struct rw_semaphore	rmdir_sem;
181 		};
182 		/* Regular file */
183 		struct {
184 			atomic_long_t	nrequests;
185 			struct nfs_mds_commit_info commit_info;
186 			struct mutex	commit_mutex;
187 		};
188 	};
189 
190 	/* Open contexts for shared mmap writes */
191 	struct list_head	open_files;
192 
193 #if IS_ENABLED(CONFIG_NFS_V4)
194 	struct nfs4_cached_acl	*nfs4_acl;
195         /* NFSv4 state */
196 	struct list_head	open_states;
197 	struct nfs_delegation __rcu *delegation;
198 	struct rw_semaphore	rwsem;
199 
200 	/* pNFS layout information */
201 	struct pnfs_layout_hdr *layout;
202 #endif /* CONFIG_NFS_V4*/
203 	/* how many bytes have been written/read and how many bytes queued up */
204 	__u64 write_io;
205 	__u64 read_io;
206 #ifdef CONFIG_NFS_FSCACHE
207 	struct fscache_cookie	*fscache;
208 #endif
209 	struct inode		vfs_inode;
210 
211 #ifdef CONFIG_NFS_V4_2
212 	struct nfs4_xattr_cache *xattr_cache;
213 #endif
214 };
215 
216 struct nfs4_copy_state {
217 	struct list_head	copies;
218 	struct list_head	src_copies;
219 	nfs4_stateid		stateid;
220 	struct completion	completion;
221 	uint64_t		count;
222 	struct nfs_writeverf	verf;
223 	int			error;
224 	int			flags;
225 	struct nfs4_state	*parent_src_state;
226 	struct nfs4_state	*parent_dst_state;
227 };
228 
229 /*
230  * Access bit flags
231  */
232 #define NFS_ACCESS_READ        0x0001
233 #define NFS_ACCESS_LOOKUP      0x0002
234 #define NFS_ACCESS_MODIFY      0x0004
235 #define NFS_ACCESS_EXTEND      0x0008
236 #define NFS_ACCESS_DELETE      0x0010
237 #define NFS_ACCESS_EXECUTE     0x0020
238 #define NFS_ACCESS_XAREAD      0x0040
239 #define NFS_ACCESS_XAWRITE     0x0080
240 #define NFS_ACCESS_XALIST      0x0100
241 
242 /*
243  * Cache validity bit flags
244  */
245 #define NFS_INO_INVALID_DATA	BIT(1)		/* cached data is invalid */
246 #define NFS_INO_INVALID_ATIME	BIT(2)		/* cached atime is invalid */
247 #define NFS_INO_INVALID_ACCESS	BIT(3)		/* cached access cred invalid */
248 #define NFS_INO_INVALID_ACL	BIT(4)		/* cached acls are invalid */
249 #define NFS_INO_REVAL_PAGECACHE	BIT(5)		/* must revalidate pagecache */
250 #define NFS_INO_REVAL_FORCED	BIT(6)		/* force revalidation ignoring a delegation */
251 #define NFS_INO_INVALID_LABEL	BIT(7)		/* cached label is invalid */
252 #define NFS_INO_INVALID_CHANGE	BIT(8)		/* cached change is invalid */
253 #define NFS_INO_INVALID_CTIME	BIT(9)		/* cached ctime is invalid */
254 #define NFS_INO_INVALID_MTIME	BIT(10)		/* cached mtime is invalid */
255 #define NFS_INO_INVALID_SIZE	BIT(11)		/* cached size is invalid */
256 #define NFS_INO_INVALID_OTHER	BIT(12)		/* other attrs are invalid */
257 #define NFS_INO_DATA_INVAL_DEFER	\
258 				BIT(13)		/* Deferred cache invalidation */
259 #define NFS_INO_INVALID_BLOCKS	BIT(14)         /* cached blocks are invalid */
260 #define NFS_INO_INVALID_XATTR	BIT(15)		/* xattrs are invalid */
261 #define NFS_INO_INVALID_NLINK	BIT(16)		/* cached nlinks is invalid */
262 #define NFS_INO_INVALID_MODE	BIT(17)		/* cached mode is invalid */
263 
264 #define NFS_INO_INVALID_ATTR	(NFS_INO_INVALID_CHANGE \
265 		| NFS_INO_INVALID_CTIME \
266 		| NFS_INO_INVALID_MTIME \
267 		| NFS_INO_INVALID_SIZE \
268 		| NFS_INO_INVALID_NLINK \
269 		| NFS_INO_INVALID_MODE \
270 		| NFS_INO_INVALID_OTHER)	/* inode metadata is invalid */
271 
272 /*
273  * Bit offsets in flags field
274  */
275 #define NFS_INO_ADVISE_RDPLUS	(0)		/* advise readdirplus */
276 #define NFS_INO_STALE		(1)		/* possible stale inode */
277 #define NFS_INO_ACL_LRU_SET	(2)		/* Inode is on the LRU list */
278 #define NFS_INO_INVALIDATING	(3)		/* inode is being invalidated */
279 #define NFS_INO_FSCACHE		(5)		/* inode can be cached by FS-Cache */
280 #define NFS_INO_FORCE_READDIR	(7)		/* force readdirplus */
281 #define NFS_INO_LAYOUTCOMMIT	(9)		/* layoutcommit required */
282 #define NFS_INO_LAYOUTCOMMITTING (10)		/* layoutcommit inflight */
283 #define NFS_INO_LAYOUTSTATS	(11)		/* layoutstats inflight */
284 #define NFS_INO_ODIRECT		(12)		/* I/O setting is O_DIRECT */
285 
286 static inline struct nfs_inode *NFS_I(const struct inode *inode)
287 {
288 	return container_of(inode, struct nfs_inode, vfs_inode);
289 }
290 
291 static inline struct nfs_server *NFS_SB(const struct super_block *s)
292 {
293 	return (struct nfs_server *)(s->s_fs_info);
294 }
295 
296 static inline struct nfs_fh *NFS_FH(const struct inode *inode)
297 {
298 	return &NFS_I(inode)->fh;
299 }
300 
301 static inline struct nfs_server *NFS_SERVER(const struct inode *inode)
302 {
303 	return NFS_SB(inode->i_sb);
304 }
305 
306 static inline struct rpc_clnt *NFS_CLIENT(const struct inode *inode)
307 {
308 	return NFS_SERVER(inode)->client;
309 }
310 
311 static inline const struct nfs_rpc_ops *NFS_PROTO(const struct inode *inode)
312 {
313 	return NFS_SERVER(inode)->nfs_client->rpc_ops;
314 }
315 
316 static inline unsigned NFS_MINATTRTIMEO(const struct inode *inode)
317 {
318 	struct nfs_server *nfss = NFS_SERVER(inode);
319 	return S_ISDIR(inode->i_mode) ? nfss->acdirmin : nfss->acregmin;
320 }
321 
322 static inline unsigned NFS_MAXATTRTIMEO(const struct inode *inode)
323 {
324 	struct nfs_server *nfss = NFS_SERVER(inode);
325 	return S_ISDIR(inode->i_mode) ? nfss->acdirmax : nfss->acregmax;
326 }
327 
328 static inline int NFS_STALE(const struct inode *inode)
329 {
330 	return test_bit(NFS_INO_STALE, &NFS_I(inode)->flags);
331 }
332 
333 static inline struct fscache_cookie *nfs_i_fscache(struct inode *inode)
334 {
335 #ifdef CONFIG_NFS_FSCACHE
336 	return NFS_I(inode)->fscache;
337 #else
338 	return NULL;
339 #endif
340 }
341 
342 static inline __u64 NFS_FILEID(const struct inode *inode)
343 {
344 	return NFS_I(inode)->fileid;
345 }
346 
347 static inline void set_nfs_fileid(struct inode *inode, __u64 fileid)
348 {
349 	NFS_I(inode)->fileid = fileid;
350 }
351 
352 static inline void nfs_mark_for_revalidate(struct inode *inode)
353 {
354 	struct nfs_inode *nfsi = NFS_I(inode);
355 
356 	spin_lock(&inode->i_lock);
357 	nfsi->cache_validity |= NFS_INO_REVAL_PAGECACHE
358 		| NFS_INO_INVALID_ACCESS
359 		| NFS_INO_INVALID_ACL
360 		| NFS_INO_INVALID_CHANGE
361 		| NFS_INO_INVALID_CTIME;
362 	if (S_ISDIR(inode->i_mode))
363 		nfsi->cache_validity |= NFS_INO_INVALID_DATA;
364 	spin_unlock(&inode->i_lock);
365 }
366 
367 static inline int nfs_server_capable(struct inode *inode, int cap)
368 {
369 	return NFS_SERVER(inode)->caps & cap;
370 }
371 
372 /**
373  * nfs_save_change_attribute - Returns the inode attribute change cookie
374  * @dir - pointer to parent directory inode
375  * The "cache change attribute" is updated when we need to revalidate
376  * our dentry cache after a directory was seen to change on the server.
377  */
378 static inline unsigned long nfs_save_change_attribute(struct inode *dir)
379 {
380 	return NFS_I(dir)->cache_change_attribute;
381 }
382 
383 /*
384  * linux/fs/nfs/inode.c
385  */
386 extern int nfs_sync_mapping(struct address_space *mapping);
387 extern void nfs_zap_mapping(struct inode *inode, struct address_space *mapping);
388 extern void nfs_zap_caches(struct inode *);
389 extern void nfs_set_inode_stale(struct inode *inode);
390 extern void nfs_invalidate_atime(struct inode *);
391 extern struct inode *nfs_fhget(struct super_block *, struct nfs_fh *,
392 				struct nfs_fattr *);
393 struct inode *nfs_ilookup(struct super_block *sb, struct nfs_fattr *, struct nfs_fh *);
394 extern int nfs_refresh_inode(struct inode *, struct nfs_fattr *);
395 extern int nfs_post_op_update_inode(struct inode *inode, struct nfs_fattr *fattr);
396 extern int nfs_post_op_update_inode_force_wcc(struct inode *inode, struct nfs_fattr *fattr);
397 extern int nfs_post_op_update_inode_force_wcc_locked(struct inode *inode, struct nfs_fattr *fattr);
398 extern int nfs_getattr(struct user_namespace *, const struct path *,
399 		       struct kstat *, u32, unsigned int);
400 extern void nfs_access_add_cache(struct inode *, struct nfs_access_entry *, const struct cred *);
401 extern void nfs_access_set_mask(struct nfs_access_entry *, u32);
402 extern int nfs_permission(struct user_namespace *, struct inode *, int);
403 extern int nfs_open(struct inode *, struct file *);
404 extern int nfs_attribute_cache_expired(struct inode *inode);
405 extern int nfs_revalidate_inode(struct inode *inode, unsigned long flags);
406 extern int __nfs_revalidate_inode(struct nfs_server *, struct inode *);
407 extern int nfs_clear_invalid_mapping(struct address_space *mapping);
408 extern bool nfs_mapping_need_revalidate_inode(struct inode *inode);
409 extern int nfs_revalidate_mapping(struct inode *inode, struct address_space *mapping);
410 extern int nfs_revalidate_mapping_rcu(struct inode *inode);
411 extern int nfs_setattr(struct user_namespace *, struct dentry *, struct iattr *);
412 extern void nfs_setattr_update_inode(struct inode *inode, struct iattr *attr, struct nfs_fattr *);
413 extern void nfs_setsecurity(struct inode *inode, struct nfs_fattr *fattr);
414 extern struct nfs_open_context *get_nfs_open_context(struct nfs_open_context *ctx);
415 extern void put_nfs_open_context(struct nfs_open_context *ctx);
416 extern struct nfs_open_context *nfs_find_open_context(struct inode *inode, const struct cred *cred, fmode_t mode);
417 extern struct nfs_open_context *alloc_nfs_open_context(struct dentry *dentry, fmode_t f_mode, struct file *filp);
418 extern void nfs_inode_attach_open_context(struct nfs_open_context *ctx);
419 extern void nfs_file_set_open_context(struct file *filp, struct nfs_open_context *ctx);
420 extern void nfs_file_clear_open_context(struct file *flip);
421 extern struct nfs_lock_context *nfs_get_lock_context(struct nfs_open_context *ctx);
422 extern void nfs_put_lock_context(struct nfs_lock_context *l_ctx);
423 extern u64 nfs_compat_user_ino64(u64 fileid);
424 extern void nfs_fattr_init(struct nfs_fattr *fattr);
425 extern void nfs_fattr_set_barrier(struct nfs_fattr *fattr);
426 extern unsigned long nfs_inc_attr_generation_counter(void);
427 
428 extern struct nfs_fattr *nfs_alloc_fattr(void);
429 extern struct nfs_fattr *nfs_alloc_fattr_with_label(struct nfs_server *server);
430 
431 static inline void nfs4_label_free(struct nfs4_label *label)
432 {
433 #ifdef CONFIG_NFS_V4_SECURITY_LABEL
434 	if (label) {
435 		kfree(label->label);
436 		kfree(label);
437 	}
438 #endif
439 }
440 
441 static inline void nfs_free_fattr(const struct nfs_fattr *fattr)
442 {
443 	if (fattr)
444 		nfs4_label_free(fattr->label);
445 	kfree(fattr);
446 }
447 
448 extern struct nfs_fh *nfs_alloc_fhandle(void);
449 
450 static inline void nfs_free_fhandle(const struct nfs_fh *fh)
451 {
452 	kfree(fh);
453 }
454 
455 #ifdef NFS_DEBUG
456 extern u32 _nfs_display_fhandle_hash(const struct nfs_fh *fh);
457 static inline u32 nfs_display_fhandle_hash(const struct nfs_fh *fh)
458 {
459 	return _nfs_display_fhandle_hash(fh);
460 }
461 extern void _nfs_display_fhandle(const struct nfs_fh *fh, const char *caption);
462 #define nfs_display_fhandle(fh, caption)			\
463 	do {							\
464 		if (unlikely(nfs_debug & NFSDBG_FACILITY))	\
465 			_nfs_display_fhandle(fh, caption);	\
466 	} while (0)
467 #else
468 static inline u32 nfs_display_fhandle_hash(const struct nfs_fh *fh)
469 {
470 	return 0;
471 }
472 static inline void nfs_display_fhandle(const struct nfs_fh *fh,
473 				       const char *caption)
474 {
475 }
476 #endif
477 
478 /*
479  * linux/fs/nfs/nfsroot.c
480  */
481 extern int  nfs_root_data(char **root_device, char **root_data); /*__init*/
482 /* linux/net/ipv4/ipconfig.c: trims ip addr off front of name, too. */
483 extern __be32 root_nfs_parse_addr(char *name); /*__init*/
484 
485 /*
486  * linux/fs/nfs/file.c
487  */
488 extern const struct file_operations nfs_file_operations;
489 #if IS_ENABLED(CONFIG_NFS_V4)
490 extern const struct file_operations nfs4_file_operations;
491 #endif /* CONFIG_NFS_V4 */
492 extern const struct address_space_operations nfs_file_aops;
493 extern const struct address_space_operations nfs_dir_aops;
494 
495 static inline struct nfs_open_context *nfs_file_open_context(struct file *filp)
496 {
497 	return filp->private_data;
498 }
499 
500 static inline const struct cred *nfs_file_cred(struct file *file)
501 {
502 	if (file != NULL) {
503 		struct nfs_open_context *ctx =
504 			nfs_file_open_context(file);
505 		if (ctx)
506 			return ctx->cred;
507 	}
508 	return NULL;
509 }
510 
511 /*
512  * linux/fs/nfs/direct.c
513  */
514 extern ssize_t nfs_direct_IO(struct kiocb *, struct iov_iter *);
515 extern ssize_t nfs_file_direct_read(struct kiocb *iocb,
516 			struct iov_iter *iter);
517 extern ssize_t nfs_file_direct_write(struct kiocb *iocb,
518 			struct iov_iter *iter);
519 
520 /*
521  * linux/fs/nfs/dir.c
522  */
523 extern const struct file_operations nfs_dir_operations;
524 extern const struct dentry_operations nfs_dentry_operations;
525 
526 extern void nfs_force_lookup_revalidate(struct inode *dir);
527 extern void nfs_set_verifier(struct dentry * dentry, unsigned long verf);
528 #if IS_ENABLED(CONFIG_NFS_V4)
529 extern void nfs_clear_verifier_delegated(struct inode *inode);
530 #endif /* IS_ENABLED(CONFIG_NFS_V4) */
531 extern struct dentry *nfs_add_or_obtain(struct dentry *dentry,
532 			struct nfs_fh *fh, struct nfs_fattr *fattr);
533 extern int nfs_instantiate(struct dentry *dentry, struct nfs_fh *fh,
534 			struct nfs_fattr *fattr);
535 extern int nfs_may_open(struct inode *inode, const struct cred *cred, int openflags);
536 extern void nfs_access_zap_cache(struct inode *inode);
537 extern int nfs_access_get_cached(struct inode *inode, const struct cred *cred,
538 				 u32 *mask, bool may_block);
539 
540 /*
541  * linux/fs/nfs/symlink.c
542  */
543 extern const struct inode_operations nfs_symlink_inode_operations;
544 
545 /*
546  * linux/fs/nfs/sysctl.c
547  */
548 #ifdef CONFIG_SYSCTL
549 extern int nfs_register_sysctl(void);
550 extern void nfs_unregister_sysctl(void);
551 #else
552 #define nfs_register_sysctl() 0
553 #define nfs_unregister_sysctl() do { } while(0)
554 #endif
555 
556 /*
557  * linux/fs/nfs/namespace.c
558  */
559 extern const struct inode_operations nfs_mountpoint_inode_operations;
560 extern const struct inode_operations nfs_referral_inode_operations;
561 extern int nfs_mountpoint_expiry_timeout;
562 extern void nfs_release_automount_timer(void);
563 
564 /*
565  * linux/fs/nfs/unlink.c
566  */
567 extern void nfs_complete_unlink(struct dentry *dentry, struct inode *);
568 
569 /*
570  * linux/fs/nfs/write.c
571  */
572 extern int  nfs_congestion_kb;
573 extern int  nfs_writepage(struct page *page, struct writeback_control *wbc);
574 extern int  nfs_writepages(struct address_space *, struct writeback_control *);
575 extern int  nfs_flush_incompatible(struct file *file, struct page *page);
576 extern int  nfs_updatepage(struct file *, struct page *, unsigned int, unsigned int);
577 
578 /*
579  * Try to write back everything synchronously (but check the
580  * return value!)
581  */
582 extern int nfs_sync_inode(struct inode *inode);
583 extern int nfs_wb_all(struct inode *inode);
584 extern int nfs_wb_page(struct inode *inode, struct page *page);
585 extern int nfs_wb_page_cancel(struct inode *inode, struct page* page);
586 extern int  nfs_commit_inode(struct inode *, int);
587 extern struct nfs_commit_data *nfs_commitdata_alloc(bool never_fail);
588 extern void nfs_commit_free(struct nfs_commit_data *data);
589 bool nfs_commit_end(struct nfs_mds_commit_info *cinfo);
590 
591 static inline int
592 nfs_have_writebacks(struct inode *inode)
593 {
594 	if (S_ISREG(inode->i_mode))
595 		return atomic_long_read(&NFS_I(inode)->nrequests) != 0;
596 	return 0;
597 }
598 
599 /*
600  * linux/fs/nfs/read.c
601  */
602 extern int  nfs_readpage(struct file *, struct page *);
603 extern int  nfs_readpages(struct file *, struct address_space *,
604 		struct list_head *, unsigned);
605 
606 /*
607  * inline functions
608  */
609 
610 static inline loff_t nfs_size_to_loff_t(__u64 size)
611 {
612 	return min_t(u64, size, OFFSET_MAX);
613 }
614 
615 static inline ino_t
616 nfs_fileid_to_ino_t(u64 fileid)
617 {
618 	ino_t ino = (ino_t) fileid;
619 	if (sizeof(ino_t) < sizeof(u64))
620 		ino ^= fileid >> (sizeof(u64)-sizeof(ino_t)) * 8;
621 	return ino;
622 }
623 
624 #define NFS_JUKEBOX_RETRY_TIME (5 * HZ)
625 
626 
627 # undef ifdebug
628 # ifdef NFS_DEBUG
629 #  define ifdebug(fac)		if (unlikely(nfs_debug & NFSDBG_##fac))
630 #  define NFS_IFDEBUG(x)	x
631 # else
632 #  define ifdebug(fac)		if (0)
633 #  define NFS_IFDEBUG(x)
634 # endif
635 #endif
636