xref: /openbmc/linux/include/linux/nfs_fs.h (revision 87c2ce3b)
1 /*
2  *  linux/include/linux/nfs_fs.h
3  *
4  *  Copyright (C) 1992  Rick Sladkey
5  *
6  *  OS-specific nfs filesystem definitions and declarations
7  */
8 
9 #ifndef _LINUX_NFS_FS_H
10 #define _LINUX_NFS_FS_H
11 
12 #include <linux/config.h>
13 #include <linux/in.h>
14 #include <linux/mm.h>
15 #include <linux/pagemap.h>
16 #include <linux/rwsem.h>
17 #include <linux/wait.h>
18 
19 #include <linux/nfs_fs_sb.h>
20 
21 #include <linux/sunrpc/debug.h>
22 #include <linux/sunrpc/auth.h>
23 #include <linux/sunrpc/clnt.h>
24 
25 #include <linux/nfs.h>
26 #include <linux/nfs2.h>
27 #include <linux/nfs3.h>
28 #include <linux/nfs4.h>
29 #include <linux/nfs_xdr.h>
30 #include <linux/rwsem.h>
31 #include <linux/mempool.h>
32 
33 /*
34  * Enable debugging support for nfs client.
35  * Requires RPC_DEBUG.
36  */
37 #ifdef RPC_DEBUG
38 # define NFS_DEBUG
39 #endif
40 
41 /* Default timeout values */
42 #define NFS_MAX_UDP_TIMEOUT	(60*HZ)
43 #define NFS_MAX_TCP_TIMEOUT	(600*HZ)
44 
45 /*
46  * superblock magic number for NFS
47  */
48 #define NFS_SUPER_MAGIC			0x6969
49 
50 /*
51  * These are the default flags for swap requests
52  */
53 #define NFS_RPC_SWAPFLAGS		(RPC_TASK_SWAPPER|RPC_TASK_ROOTCREDS)
54 
55 /*
56  * When flushing a cluster of dirty pages, there can be different
57  * strategies:
58  */
59 #define FLUSH_AGING		0	/* only flush old buffers */
60 #define FLUSH_SYNC		1	/* file being synced, or contention */
61 #define FLUSH_WAIT		2	/* wait for completion */
62 #define FLUSH_STABLE		4	/* commit to stable storage */
63 #define FLUSH_LOWPRI		8	/* low priority background flush */
64 #define FLUSH_HIGHPRI		16	/* high priority memory reclaim flush */
65 #define FLUSH_NOCOMMIT		32	/* Don't send the NFSv3/v4 COMMIT */
66 
67 #ifdef __KERNEL__
68 
69 /*
70  * NFSv3/v4 Access mode cache entry
71  */
72 struct nfs_access_entry {
73 	unsigned long		jiffies;
74 	struct rpc_cred *	cred;
75 	int			mask;
76 };
77 
78 struct nfs4_state;
79 struct nfs_open_context {
80 	atomic_t count;
81 	struct dentry *dentry;
82 	struct rpc_cred *cred;
83 	struct nfs4_state *state;
84 	fl_owner_t lockowner;
85 	int mode;
86 	int error;
87 
88 	struct list_head list;
89 
90 	__u64 dir_cookie;
91 };
92 
93 /*
94  * NFSv4 delegation
95  */
96 struct nfs_delegation;
97 
98 struct posix_acl;
99 
100 /*
101  * nfs fs inode data in memory
102  */
103 struct nfs_inode {
104 	/*
105 	 * The 64bit 'inode number'
106 	 */
107 	__u64 fileid;
108 
109 	/*
110 	 * NFS file handle
111 	 */
112 	struct nfs_fh		fh;
113 
114 	/*
115 	 * Various flags
116 	 */
117 	unsigned long		flags;			/* atomic bit ops */
118 	unsigned long		cache_validity;		/* bit mask */
119 
120 	/*
121 	 * read_cache_jiffies is when we started read-caching this inode,
122 	 * and read_cache_mtime is the mtime of the inode at that time.
123 	 * attrtimeo is for how long the cached information is assumed
124 	 * to be valid. A successful attribute revalidation doubles
125 	 * attrtimeo (up to acregmax/acdirmax), a failure resets it to
126 	 * acregmin/acdirmin.
127 	 *
128 	 * We need to revalidate the cached attrs for this inode if
129 	 *
130 	 *	jiffies - read_cache_jiffies > attrtimeo
131 	 *
132 	 * and invalidate any cached data/flush out any dirty pages if
133 	 * we find that
134 	 *
135 	 *	mtime != read_cache_mtime
136 	 */
137 	unsigned long		read_cache_jiffies;
138 	unsigned long		attrtimeo;
139 	unsigned long		attrtimeo_timestamp;
140 	__u64			change_attr;		/* v4 only */
141 
142 	unsigned long		last_updated;
143 	/* "Generation counter" for the attribute cache. This is
144 	 * bumped whenever we update the metadata on the
145 	 * server.
146 	 */
147 	unsigned long		cache_change_attribute;
148 	/*
149 	 * Counter indicating the number of outstanding requests that
150 	 * will cause a file data update.
151 	 */
152 	atomic_t		data_updates;
153 
154 	struct nfs_access_entry	cache_access;
155 #ifdef CONFIG_NFS_V3_ACL
156 	struct posix_acl	*acl_access;
157 	struct posix_acl	*acl_default;
158 #endif
159 
160 	/*
161 	 * This is the cookie verifier used for NFSv3 readdir
162 	 * operations
163 	 */
164 	__u32			cookieverf[2];
165 
166 	/*
167 	 * This is the list of dirty unwritten pages.
168 	 */
169 	spinlock_t		req_lock;
170 	struct list_head	dirty;
171 	struct list_head	commit;
172 	struct radix_tree_root	nfs_page_tree;
173 
174 	unsigned int		ndirty,
175 				ncommit,
176 				npages;
177 
178 	/* Open contexts for shared mmap writes */
179 	struct list_head	open_files;
180 
181 #ifdef CONFIG_NFS_V4
182 	struct nfs4_cached_acl	*nfs4_acl;
183         /* NFSv4 state */
184 	struct list_head	open_states;
185 	struct nfs_delegation	*delegation;
186 	int			 delegation_state;
187 	struct rw_semaphore	rwsem;
188 #endif /* CONFIG_NFS_V4*/
189 	struct inode		vfs_inode;
190 };
191 
192 /*
193  * Cache validity bit flags
194  */
195 #define NFS_INO_INVALID_ATTR	0x0001		/* cached attrs are invalid */
196 #define NFS_INO_INVALID_DATA	0x0002		/* cached data is invalid */
197 #define NFS_INO_INVALID_ATIME	0x0004		/* cached atime is invalid */
198 #define NFS_INO_INVALID_ACCESS	0x0008		/* cached access cred invalid */
199 #define NFS_INO_INVALID_ACL	0x0010		/* cached acls are invalid */
200 #define NFS_INO_REVAL_PAGECACHE	0x0020		/* must revalidate pagecache */
201 
202 /*
203  * Bit offsets in flags field
204  */
205 #define NFS_INO_REVALIDATING	(0)		/* revalidating attrs */
206 #define NFS_INO_ADVISE_RDPLUS	(1)		/* advise readdirplus */
207 #define NFS_INO_STALE		(2)		/* possible stale inode */
208 
209 static inline struct nfs_inode *NFS_I(struct inode *inode)
210 {
211 	return container_of(inode, struct nfs_inode, vfs_inode);
212 }
213 #define NFS_SB(s)		((struct nfs_server *)(s->s_fs_info))
214 
215 #define NFS_FH(inode)			(&NFS_I(inode)->fh)
216 #define NFS_SERVER(inode)		(NFS_SB(inode->i_sb))
217 #define NFS_CLIENT(inode)		(NFS_SERVER(inode)->client)
218 #define NFS_PROTO(inode)		(NFS_SERVER(inode)->rpc_ops)
219 #define NFS_ADDR(inode)			(RPC_PEERADDR(NFS_CLIENT(inode)))
220 #define NFS_COOKIEVERF(inode)		(NFS_I(inode)->cookieverf)
221 #define NFS_READTIME(inode)		(NFS_I(inode)->read_cache_jiffies)
222 #define NFS_CHANGE_ATTR(inode)		(NFS_I(inode)->change_attr)
223 #define NFS_ATTRTIMEO(inode)		(NFS_I(inode)->attrtimeo)
224 #define NFS_MINATTRTIMEO(inode) \
225 	(S_ISDIR(inode->i_mode)? NFS_SERVER(inode)->acdirmin \
226 			       : NFS_SERVER(inode)->acregmin)
227 #define NFS_MAXATTRTIMEO(inode) \
228 	(S_ISDIR(inode->i_mode)? NFS_SERVER(inode)->acdirmax \
229 			       : NFS_SERVER(inode)->acregmax)
230 #define NFS_ATTRTIMEO_UPDATE(inode)	(NFS_I(inode)->attrtimeo_timestamp)
231 
232 #define NFS_FLAGS(inode)		(NFS_I(inode)->flags)
233 #define NFS_STALE(inode)		(test_bit(NFS_INO_STALE, &NFS_FLAGS(inode)))
234 
235 #define NFS_FILEID(inode)		(NFS_I(inode)->fileid)
236 
237 static inline int nfs_caches_unstable(struct inode *inode)
238 {
239 	return atomic_read(&NFS_I(inode)->data_updates) != 0;
240 }
241 
242 static inline void nfs_mark_for_revalidate(struct inode *inode)
243 {
244 	spin_lock(&inode->i_lock);
245 	NFS_I(inode)->cache_validity |= NFS_INO_INVALID_ATTR | NFS_INO_INVALID_ACCESS;
246 	spin_unlock(&inode->i_lock);
247 }
248 
249 static inline void NFS_CACHEINV(struct inode *inode)
250 {
251 	if (!nfs_caches_unstable(inode))
252 		nfs_mark_for_revalidate(inode);
253 }
254 
255 static inline int nfs_server_capable(struct inode *inode, int cap)
256 {
257 	return NFS_SERVER(inode)->caps & cap;
258 }
259 
260 static inline int NFS_USE_READDIRPLUS(struct inode *inode)
261 {
262 	return test_bit(NFS_INO_ADVISE_RDPLUS, &NFS_FLAGS(inode));
263 }
264 
265 /**
266  * nfs_save_change_attribute - Returns the inode attribute change cookie
267  * @inode - pointer to inode
268  * The "change attribute" is updated every time we finish an operation
269  * that will result in a metadata change on the server.
270  */
271 static inline long nfs_save_change_attribute(struct inode *inode)
272 {
273 	return NFS_I(inode)->cache_change_attribute;
274 }
275 
276 /**
277  * nfs_verify_change_attribute - Detects NFS inode cache updates
278  * @inode - pointer to inode
279  * @chattr - previously saved change attribute
280  * Return "false" if metadata has been updated (or is in the process of
281  * being updated) since the change attribute was saved.
282  */
283 static inline int nfs_verify_change_attribute(struct inode *inode, unsigned long chattr)
284 {
285 	return !nfs_caches_unstable(inode)
286 		&& time_after_eq(chattr, NFS_I(inode)->cache_change_attribute);
287 }
288 
289 /*
290  * linux/fs/nfs/inode.c
291  */
292 extern int nfs_sync_mapping(struct address_space *mapping);
293 extern void nfs_zap_caches(struct inode *);
294 extern struct inode *nfs_fhget(struct super_block *, struct nfs_fh *,
295 				struct nfs_fattr *);
296 extern int nfs_refresh_inode(struct inode *, struct nfs_fattr *);
297 extern int nfs_post_op_update_inode(struct inode *inode, struct nfs_fattr *fattr);
298 extern int nfs_getattr(struct vfsmount *, struct dentry *, struct kstat *);
299 extern int nfs_permission(struct inode *, int, struct nameidata *);
300 extern int nfs_access_get_cached(struct inode *, struct rpc_cred *, struct nfs_access_entry *);
301 extern void nfs_access_add_cache(struct inode *, struct nfs_access_entry *);
302 extern int nfs_open(struct inode *, struct file *);
303 extern int nfs_release(struct inode *, struct file *);
304 extern int nfs_attribute_timeout(struct inode *inode);
305 extern int nfs_revalidate_inode(struct nfs_server *server, struct inode *inode);
306 extern int __nfs_revalidate_inode(struct nfs_server *, struct inode *);
307 extern void nfs_revalidate_mapping(struct inode *inode, struct address_space *mapping);
308 extern int nfs_setattr(struct dentry *, struct iattr *);
309 extern void nfs_setattr_update_inode(struct inode *inode, struct iattr *attr);
310 extern void nfs_begin_attr_update(struct inode *);
311 extern void nfs_end_attr_update(struct inode *);
312 extern void nfs_begin_data_update(struct inode *);
313 extern void nfs_end_data_update(struct inode *);
314 extern struct nfs_open_context *alloc_nfs_open_context(struct dentry *dentry, struct rpc_cred *cred);
315 extern struct nfs_open_context *get_nfs_open_context(struct nfs_open_context *ctx);
316 extern void put_nfs_open_context(struct nfs_open_context *ctx);
317 extern void nfs_file_set_open_context(struct file *filp, struct nfs_open_context *ctx);
318 extern struct nfs_open_context *nfs_find_open_context(struct inode *inode, struct rpc_cred *cred, int mode);
319 extern void nfs_file_clear_open_context(struct file *filp);
320 
321 /* linux/net/ipv4/ipconfig.c: trims ip addr off front of name, too. */
322 extern u32 root_nfs_parse_addr(char *name); /*__init*/
323 
324 static inline void nfs_fattr_init(struct nfs_fattr *fattr)
325 {
326 	fattr->valid = 0;
327 	fattr->time_start = jiffies;
328 }
329 
330 /*
331  * linux/fs/nfs/file.c
332  */
333 extern struct inode_operations nfs_file_inode_operations;
334 #ifdef CONFIG_NFS_V3
335 extern struct inode_operations nfs3_file_inode_operations;
336 #endif /* CONFIG_NFS_V3 */
337 extern struct file_operations nfs_file_operations;
338 extern struct address_space_operations nfs_file_aops;
339 
340 static inline struct rpc_cred *nfs_file_cred(struct file *file)
341 {
342 	if (file != NULL) {
343 		struct nfs_open_context *ctx;
344 
345 		ctx = (struct nfs_open_context*)file->private_data;
346 		return ctx->cred;
347 	}
348 	return NULL;
349 }
350 
351 /*
352  * linux/fs/nfs/xattr.c
353  */
354 #ifdef CONFIG_NFS_V3_ACL
355 extern ssize_t nfs3_listxattr(struct dentry *, char *, size_t);
356 extern ssize_t nfs3_getxattr(struct dentry *, const char *, void *, size_t);
357 extern int nfs3_setxattr(struct dentry *, const char *,
358 			const void *, size_t, int);
359 extern int nfs3_removexattr (struct dentry *, const char *name);
360 #else
361 # define nfs3_listxattr NULL
362 # define nfs3_getxattr NULL
363 # define nfs3_setxattr NULL
364 # define nfs3_removexattr NULL
365 #endif
366 
367 /*
368  * linux/fs/nfs/direct.c
369  */
370 extern ssize_t nfs_direct_IO(int, struct kiocb *, const struct iovec *, loff_t,
371 			unsigned long);
372 extern ssize_t nfs_file_direct_read(struct kiocb *iocb, char __user *buf,
373 			size_t count, loff_t pos);
374 extern ssize_t nfs_file_direct_write(struct kiocb *iocb, const char __user *buf,
375 			size_t count, loff_t pos);
376 
377 /*
378  * linux/fs/nfs/dir.c
379  */
380 extern struct inode_operations nfs_dir_inode_operations;
381 #ifdef CONFIG_NFS_V3
382 extern struct inode_operations nfs3_dir_inode_operations;
383 #endif /* CONFIG_NFS_V3 */
384 extern struct file_operations nfs_dir_operations;
385 extern struct dentry_operations nfs_dentry_operations;
386 
387 extern int nfs_instantiate(struct dentry *dentry, struct nfs_fh *fh, struct nfs_fattr *fattr);
388 
389 /*
390  * linux/fs/nfs/symlink.c
391  */
392 extern struct inode_operations nfs_symlink_inode_operations;
393 
394 /*
395  * linux/fs/nfs/sysctl.c
396  */
397 #ifdef CONFIG_SYSCTL
398 extern int nfs_register_sysctl(void);
399 extern void nfs_unregister_sysctl(void);
400 #else
401 #define nfs_register_sysctl() do { } while(0)
402 #define nfs_unregister_sysctl() do { } while(0)
403 #endif
404 
405 /*
406  * linux/fs/nfs/unlink.c
407  */
408 extern int  nfs_async_unlink(struct dentry *);
409 extern void nfs_complete_unlink(struct dentry *);
410 
411 /*
412  * linux/fs/nfs/write.c
413  */
414 extern int  nfs_writepage(struct page *page, struct writeback_control *wbc);
415 extern int  nfs_writepages(struct address_space *, struct writeback_control *);
416 extern int  nfs_flush_incompatible(struct file *file, struct page *page);
417 extern int  nfs_updatepage(struct file *, struct page *, unsigned int, unsigned int);
418 extern void nfs_writeback_done(struct rpc_task *task, void *data);
419 extern void nfs_writedata_release(void *data);
420 
421 #if defined(CONFIG_NFS_V3) || defined(CONFIG_NFS_V4)
422 extern void nfs_commit_done(struct rpc_task *, void *data);
423 extern void nfs_commit_release(void *data);
424 #endif
425 
426 /*
427  * Try to write back everything synchronously (but check the
428  * return value!)
429  */
430 extern int  nfs_sync_inode(struct inode *, unsigned long, unsigned int, int);
431 #if defined(CONFIG_NFS_V3) || defined(CONFIG_NFS_V4)
432 extern int  nfs_commit_inode(struct inode *, int);
433 #else
434 static inline int
435 nfs_commit_inode(struct inode *inode, int how)
436 {
437 	return 0;
438 }
439 #endif
440 
441 static inline int
442 nfs_have_writebacks(struct inode *inode)
443 {
444 	return NFS_I(inode)->npages != 0;
445 }
446 
447 static inline int
448 nfs_wb_all(struct inode *inode)
449 {
450 	int error = nfs_sync_inode(inode, 0, 0, FLUSH_WAIT);
451 	return (error < 0) ? error : 0;
452 }
453 
454 /*
455  * Write back all requests on one page - we do this before reading it.
456  */
457 static inline int nfs_wb_page_priority(struct inode *inode, struct page* page, int how)
458 {
459 	int error = nfs_sync_inode(inode, page->index, 1,
460 			how | FLUSH_WAIT | FLUSH_STABLE);
461 	return (error < 0) ? error : 0;
462 }
463 
464 static inline int nfs_wb_page(struct inode *inode, struct page* page)
465 {
466 	return nfs_wb_page_priority(inode, page, 0);
467 }
468 
469 /*
470  * Allocate and free nfs_write_data structures
471  */
472 extern mempool_t *nfs_wdata_mempool;
473 
474 static inline struct nfs_write_data *nfs_writedata_alloc(unsigned int pagecount)
475 {
476 	struct nfs_write_data *p = mempool_alloc(nfs_wdata_mempool, SLAB_NOFS);
477 
478 	if (p) {
479 		memset(p, 0, sizeof(*p));
480 		INIT_LIST_HEAD(&p->pages);
481 		if (pagecount < NFS_PAGEVEC_SIZE)
482 			p->pagevec = &p->page_array[0];
483 		else {
484 			size_t size = ++pagecount * sizeof(struct page *);
485 			p->pagevec = kmalloc(size, GFP_NOFS);
486 			if (p->pagevec) {
487 				memset(p->pagevec, 0, size);
488 			} else {
489 				mempool_free(p, nfs_wdata_mempool);
490 				p = NULL;
491 			}
492 		}
493 	}
494 	return p;
495 }
496 
497 static inline void nfs_writedata_free(struct nfs_write_data *p)
498 {
499 	if (p && (p->pagevec != &p->page_array[0]))
500 		kfree(p->pagevec);
501 	mempool_free(p, nfs_wdata_mempool);
502 }
503 
504 /*
505  * linux/fs/nfs/read.c
506  */
507 extern int  nfs_readpage(struct file *, struct page *);
508 extern int  nfs_readpages(struct file *, struct address_space *,
509 		struct list_head *, unsigned);
510 extern void nfs_readpage_result(struct rpc_task *, void *);
511 extern void  nfs_readdata_release(void *data);
512 
513 
514 /*
515  * Allocate and free nfs_read_data structures
516  */
517 extern mempool_t *nfs_rdata_mempool;
518 
519 static inline struct nfs_read_data *nfs_readdata_alloc(unsigned int pagecount)
520 {
521 	struct nfs_read_data *p = mempool_alloc(nfs_rdata_mempool, SLAB_NOFS);
522 
523 	if (p) {
524 		memset(p, 0, sizeof(*p));
525 		INIT_LIST_HEAD(&p->pages);
526 		if (pagecount < NFS_PAGEVEC_SIZE)
527 			p->pagevec = &p->page_array[0];
528 		else {
529 			size_t size = ++pagecount * sizeof(struct page *);
530 			p->pagevec = kmalloc(size, GFP_NOFS);
531 			if (p->pagevec) {
532 				memset(p->pagevec, 0, size);
533 			} else {
534 				mempool_free(p, nfs_rdata_mempool);
535 				p = NULL;
536 			}
537 		}
538 	}
539 	return p;
540 }
541 
542 static inline void nfs_readdata_free(struct nfs_read_data *p)
543 {
544 	if (p && (p->pagevec != &p->page_array[0]))
545 		kfree(p->pagevec);
546 	mempool_free(p, nfs_rdata_mempool);
547 }
548 
549 /*
550  * linux/fs/nfs3proc.c
551  */
552 #ifdef CONFIG_NFS_V3_ACL
553 extern struct posix_acl *nfs3_proc_getacl(struct inode *inode, int type);
554 extern int nfs3_proc_setacl(struct inode *inode, int type,
555 			    struct posix_acl *acl);
556 extern int nfs3_proc_set_default_acl(struct inode *dir, struct inode *inode,
557 		mode_t mode);
558 extern void nfs3_forget_cached_acls(struct inode *inode);
559 #else
560 static inline int nfs3_proc_set_default_acl(struct inode *dir,
561 					    struct inode *inode,
562 					    mode_t mode)
563 {
564 	return 0;
565 }
566 
567 static inline void nfs3_forget_cached_acls(struct inode *inode)
568 {
569 }
570 #endif /* CONFIG_NFS_V3_ACL */
571 
572 /*
573  * linux/fs/mount_clnt.c
574  * (Used only by nfsroot module)
575  */
576 extern int  nfsroot_mount(struct sockaddr_in *, char *, struct nfs_fh *,
577 		int, int);
578 
579 /*
580  * inline functions
581  */
582 
583 static inline loff_t
584 nfs_size_to_loff_t(__u64 size)
585 {
586 	loff_t maxsz = (((loff_t) ULONG_MAX) << PAGE_CACHE_SHIFT) + PAGE_CACHE_SIZE - 1;
587 	if (size > maxsz)
588 		return maxsz;
589 	return (loff_t) size;
590 }
591 
592 static inline ino_t
593 nfs_fileid_to_ino_t(u64 fileid)
594 {
595 	ino_t ino = (ino_t) fileid;
596 	if (sizeof(ino_t) < sizeof(u64))
597 		ino ^= fileid >> (sizeof(u64)-sizeof(ino_t)) * 8;
598 	return ino;
599 }
600 
601 /* NFS root */
602 
603 extern void * nfs_root_data(void);
604 
605 #define nfs_wait_event(clnt, wq, condition)				\
606 ({									\
607 	int __retval = 0;						\
608 	if (clnt->cl_intr) {						\
609 		sigset_t oldmask;					\
610 		rpc_clnt_sigmask(clnt, &oldmask);			\
611 		__retval = wait_event_interruptible(wq, condition);	\
612 		rpc_clnt_sigunmask(clnt, &oldmask);			\
613 	} else								\
614 		wait_event(wq, condition);				\
615 	__retval;							\
616 })
617 
618 #define NFS_JUKEBOX_RETRY_TIME (5 * HZ)
619 
620 #endif /* __KERNEL__ */
621 
622 /*
623  * NFS debug flags
624  */
625 #define NFSDBG_VFS		0x0001
626 #define NFSDBG_DIRCACHE		0x0002
627 #define NFSDBG_LOOKUPCACHE	0x0004
628 #define NFSDBG_PAGECACHE	0x0008
629 #define NFSDBG_PROC		0x0010
630 #define NFSDBG_XDR		0x0020
631 #define NFSDBG_FILE		0x0040
632 #define NFSDBG_ROOT		0x0080
633 #define NFSDBG_CALLBACK		0x0100
634 #define NFSDBG_ALL		0xFFFF
635 
636 #ifdef __KERNEL__
637 # undef ifdebug
638 # ifdef NFS_DEBUG
639 #  define ifdebug(fac)		if (unlikely(nfs_debug & NFSDBG_##fac))
640 # else
641 #  define ifdebug(fac)		if (0)
642 # endif
643 #endif /* __KERNEL */
644 
645 #endif
646