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 * Size of the NFS directory verifier 50 */ 51 #define NFS_DIR_VERIFIER_SIZE 2 52 53 /* 54 * NFSv3/v4 Access mode cache entry 55 */ 56 struct nfs_access_entry { 57 struct rb_node rb_node; 58 struct list_head lru; 59 kuid_t fsuid; 60 kgid_t fsgid; 61 struct group_info *group_info; 62 __u32 mask; 63 struct rcu_head rcu_head; 64 }; 65 66 struct nfs_lock_context { 67 refcount_t count; 68 struct list_head list; 69 struct nfs_open_context *open_context; 70 fl_owner_t lockowner; 71 atomic_t io_count; 72 struct rcu_head rcu_head; 73 }; 74 75 struct nfs4_state; 76 struct nfs_open_context { 77 struct nfs_lock_context lock_context; 78 fl_owner_t flock_owner; 79 struct dentry *dentry; 80 const struct cred *cred; 81 struct rpc_cred __rcu *ll_cred; /* low-level cred - use to check for expiry */ 82 struct nfs4_state *state; 83 fmode_t mode; 84 85 unsigned long flags; 86 #define NFS_CONTEXT_RESEND_WRITES (1) 87 #define NFS_CONTEXT_BAD (2) 88 #define NFS_CONTEXT_UNLOCK (3) 89 #define NFS_CONTEXT_FILE_OPEN (4) 90 int error; 91 92 struct list_head list; 93 struct nfs4_threshold *mdsthreshold; 94 struct rcu_head rcu_head; 95 }; 96 97 struct nfs_open_dir_context { 98 struct list_head list; 99 atomic_t cache_hits; 100 atomic_t cache_misses; 101 unsigned long attr_gencount; 102 __be32 verf[NFS_DIR_VERIFIER_SIZE]; 103 __u64 dir_cookie; 104 __u64 last_cookie; 105 pgoff_t page_index; 106 unsigned int dtsize; 107 bool force_clear; 108 bool eof; 109 struct rcu_head rcu_head; 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_FORCED BIT(6) /* force revalidation ignoring a delegation */ 250 #define NFS_INO_INVALID_LABEL BIT(7) /* cached label is invalid */ 251 #define NFS_INO_INVALID_CHANGE BIT(8) /* cached change is invalid */ 252 #define NFS_INO_INVALID_CTIME BIT(9) /* cached ctime is invalid */ 253 #define NFS_INO_INVALID_MTIME BIT(10) /* cached mtime is invalid */ 254 #define NFS_INO_INVALID_SIZE BIT(11) /* cached size is invalid */ 255 #define NFS_INO_INVALID_OTHER BIT(12) /* other attrs are invalid */ 256 #define NFS_INO_DATA_INVAL_DEFER \ 257 BIT(13) /* Deferred cache invalidation */ 258 #define NFS_INO_INVALID_BLOCKS BIT(14) /* cached blocks are invalid */ 259 #define NFS_INO_INVALID_XATTR BIT(15) /* xattrs are invalid */ 260 #define NFS_INO_INVALID_NLINK BIT(16) /* cached nlinks is invalid */ 261 #define NFS_INO_INVALID_MODE BIT(17) /* cached mode is invalid */ 262 263 #define NFS_INO_INVALID_ATTR (NFS_INO_INVALID_CHANGE \ 264 | NFS_INO_INVALID_CTIME \ 265 | NFS_INO_INVALID_MTIME \ 266 | NFS_INO_INVALID_SIZE \ 267 | NFS_INO_INVALID_NLINK \ 268 | NFS_INO_INVALID_MODE \ 269 | NFS_INO_INVALID_OTHER) /* inode metadata is invalid */ 270 271 /* 272 * Bit offsets in flags field 273 */ 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_PRESERVE_UNLINKED (4) /* preserve file if removed while open */ 278 #define NFS_INO_FSCACHE (5) /* inode can be cached by FS-Cache */ 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_INVALID_ACCESS | NFS_INO_INVALID_ACL | 356 NFS_INO_INVALID_CHANGE | NFS_INO_INVALID_CTIME | 357 NFS_INO_INVALID_SIZE; 358 if (S_ISDIR(inode->i_mode)) 359 nfsi->cache_validity |= NFS_INO_INVALID_DATA; 360 spin_unlock(&inode->i_lock); 361 } 362 363 static inline int nfs_server_capable(const struct inode *inode, int cap) 364 { 365 return NFS_SERVER(inode)->caps & cap; 366 } 367 368 /** 369 * nfs_save_change_attribute - Returns the inode attribute change cookie 370 * @dir - pointer to parent directory inode 371 * The "cache change attribute" is updated when we need to revalidate 372 * our dentry cache after a directory was seen to change on the server. 373 */ 374 static inline unsigned long nfs_save_change_attribute(struct inode *dir) 375 { 376 return NFS_I(dir)->cache_change_attribute; 377 } 378 379 /* 380 * linux/fs/nfs/inode.c 381 */ 382 extern int nfs_sync_mapping(struct address_space *mapping); 383 extern void nfs_zap_mapping(struct inode *inode, struct address_space *mapping); 384 extern void nfs_zap_caches(struct inode *); 385 extern void nfs_set_inode_stale(struct inode *inode); 386 extern void nfs_invalidate_atime(struct inode *); 387 extern struct inode *nfs_fhget(struct super_block *, struct nfs_fh *, 388 struct nfs_fattr *); 389 struct inode *nfs_ilookup(struct super_block *sb, struct nfs_fattr *, struct nfs_fh *); 390 extern int nfs_refresh_inode(struct inode *, struct nfs_fattr *); 391 extern int nfs_post_op_update_inode(struct inode *inode, struct nfs_fattr *fattr); 392 extern int nfs_post_op_update_inode_force_wcc(struct inode *inode, struct nfs_fattr *fattr); 393 extern int nfs_post_op_update_inode_force_wcc_locked(struct inode *inode, struct nfs_fattr *fattr); 394 extern int nfs_getattr(struct user_namespace *, const struct path *, 395 struct kstat *, u32, unsigned int); 396 extern void nfs_access_add_cache(struct inode *, struct nfs_access_entry *, const struct cred *); 397 extern void nfs_access_set_mask(struct nfs_access_entry *, u32); 398 extern int nfs_permission(struct user_namespace *, struct inode *, int); 399 extern int nfs_open(struct inode *, struct file *); 400 extern int nfs_attribute_cache_expired(struct inode *inode); 401 extern int nfs_revalidate_inode(struct inode *inode, unsigned long flags); 402 extern int __nfs_revalidate_inode(struct nfs_server *, struct inode *); 403 extern int nfs_clear_invalid_mapping(struct address_space *mapping); 404 extern bool nfs_mapping_need_revalidate_inode(struct inode *inode); 405 extern int nfs_revalidate_mapping(struct inode *inode, struct address_space *mapping); 406 extern int nfs_revalidate_mapping_rcu(struct inode *inode); 407 extern int nfs_setattr(struct user_namespace *, struct dentry *, struct iattr *); 408 extern void nfs_setattr_update_inode(struct inode *inode, struct iattr *attr, struct nfs_fattr *); 409 extern void nfs_setsecurity(struct inode *inode, struct nfs_fattr *fattr); 410 extern struct nfs_open_context *get_nfs_open_context(struct nfs_open_context *ctx); 411 extern void put_nfs_open_context(struct nfs_open_context *ctx); 412 extern struct nfs_open_context *nfs_find_open_context(struct inode *inode, const struct cred *cred, fmode_t mode); 413 extern struct nfs_open_context *alloc_nfs_open_context(struct dentry *dentry, fmode_t f_mode, struct file *filp); 414 extern void nfs_inode_attach_open_context(struct nfs_open_context *ctx); 415 extern void nfs_file_set_open_context(struct file *filp, struct nfs_open_context *ctx); 416 extern void nfs_file_clear_open_context(struct file *flip); 417 extern struct nfs_lock_context *nfs_get_lock_context(struct nfs_open_context *ctx); 418 extern void nfs_put_lock_context(struct nfs_lock_context *l_ctx); 419 extern u64 nfs_compat_user_ino64(u64 fileid); 420 extern void nfs_fattr_init(struct nfs_fattr *fattr); 421 extern void nfs_fattr_set_barrier(struct nfs_fattr *fattr); 422 extern unsigned long nfs_inc_attr_generation_counter(void); 423 424 extern struct nfs_fattr *nfs_alloc_fattr(void); 425 extern struct nfs_fattr *nfs_alloc_fattr_with_label(struct nfs_server *server); 426 427 static inline void nfs4_label_free(struct nfs4_label *label) 428 { 429 #ifdef CONFIG_NFS_V4_SECURITY_LABEL 430 if (label) { 431 kfree(label->label); 432 kfree(label); 433 } 434 #endif 435 } 436 437 static inline void nfs_free_fattr(const struct nfs_fattr *fattr) 438 { 439 if (fattr) 440 nfs4_label_free(fattr->label); 441 kfree(fattr); 442 } 443 444 extern struct nfs_fh *nfs_alloc_fhandle(void); 445 446 static inline void nfs_free_fhandle(const struct nfs_fh *fh) 447 { 448 kfree(fh); 449 } 450 451 #ifdef NFS_DEBUG 452 extern u32 _nfs_display_fhandle_hash(const struct nfs_fh *fh); 453 static inline u32 nfs_display_fhandle_hash(const struct nfs_fh *fh) 454 { 455 return _nfs_display_fhandle_hash(fh); 456 } 457 extern void _nfs_display_fhandle(const struct nfs_fh *fh, const char *caption); 458 #define nfs_display_fhandle(fh, caption) \ 459 do { \ 460 if (unlikely(nfs_debug & NFSDBG_FACILITY)) \ 461 _nfs_display_fhandle(fh, caption); \ 462 } while (0) 463 #else 464 static inline u32 nfs_display_fhandle_hash(const struct nfs_fh *fh) 465 { 466 return 0; 467 } 468 static inline void nfs_display_fhandle(const struct nfs_fh *fh, 469 const char *caption) 470 { 471 } 472 #endif 473 474 /* 475 * linux/fs/nfs/nfsroot.c 476 */ 477 extern int nfs_root_data(char **root_device, char **root_data); /*__init*/ 478 /* linux/net/ipv4/ipconfig.c: trims ip addr off front of name, too. */ 479 extern __be32 root_nfs_parse_addr(char *name); /*__init*/ 480 481 /* 482 * linux/fs/nfs/file.c 483 */ 484 extern const struct file_operations nfs_file_operations; 485 #if IS_ENABLED(CONFIG_NFS_V4) 486 extern const struct file_operations nfs4_file_operations; 487 #endif /* CONFIG_NFS_V4 */ 488 extern const struct address_space_operations nfs_file_aops; 489 extern const struct address_space_operations nfs_dir_aops; 490 491 static inline struct nfs_open_context *nfs_file_open_context(struct file *filp) 492 { 493 return filp->private_data; 494 } 495 496 static inline const struct cred *nfs_file_cred(struct file *file) 497 { 498 if (file != NULL) { 499 struct nfs_open_context *ctx = 500 nfs_file_open_context(file); 501 if (ctx) 502 return ctx->cred; 503 } 504 return NULL; 505 } 506 507 /* 508 * linux/fs/nfs/direct.c 509 */ 510 extern ssize_t nfs_direct_IO(struct kiocb *, struct iov_iter *); 511 ssize_t nfs_file_direct_read(struct kiocb *iocb, 512 struct iov_iter *iter, bool swap); 513 ssize_t nfs_file_direct_write(struct kiocb *iocb, 514 struct iov_iter *iter, bool swap); 515 516 /* 517 * linux/fs/nfs/dir.c 518 */ 519 extern const struct file_operations nfs_dir_operations; 520 extern const struct dentry_operations nfs_dentry_operations; 521 522 extern void nfs_force_lookup_revalidate(struct inode *dir); 523 extern void nfs_set_verifier(struct dentry * dentry, unsigned long verf); 524 #if IS_ENABLED(CONFIG_NFS_V4) 525 extern void nfs_clear_verifier_delegated(struct inode *inode); 526 #endif /* IS_ENABLED(CONFIG_NFS_V4) */ 527 extern struct dentry *nfs_add_or_obtain(struct dentry *dentry, 528 struct nfs_fh *fh, struct nfs_fattr *fattr); 529 extern int nfs_instantiate(struct dentry *dentry, struct nfs_fh *fh, 530 struct nfs_fattr *fattr); 531 extern int nfs_may_open(struct inode *inode, const struct cred *cred, int openflags); 532 extern void nfs_access_zap_cache(struct inode *inode); 533 extern int nfs_access_get_cached(struct inode *inode, const struct cred *cred, 534 u32 *mask, bool may_block); 535 536 /* 537 * linux/fs/nfs/symlink.c 538 */ 539 extern const struct inode_operations nfs_symlink_inode_operations; 540 541 /* 542 * linux/fs/nfs/sysctl.c 543 */ 544 #ifdef CONFIG_SYSCTL 545 extern int nfs_register_sysctl(void); 546 extern void nfs_unregister_sysctl(void); 547 #else 548 #define nfs_register_sysctl() 0 549 #define nfs_unregister_sysctl() do { } while(0) 550 #endif 551 552 /* 553 * linux/fs/nfs/namespace.c 554 */ 555 extern const struct inode_operations nfs_mountpoint_inode_operations; 556 extern const struct inode_operations nfs_referral_inode_operations; 557 extern int nfs_mountpoint_expiry_timeout; 558 extern void nfs_release_automount_timer(void); 559 560 /* 561 * linux/fs/nfs/unlink.c 562 */ 563 extern void nfs_complete_unlink(struct dentry *dentry, struct inode *); 564 565 /* 566 * linux/fs/nfs/write.c 567 */ 568 extern int nfs_congestion_kb; 569 extern int nfs_writepage(struct page *page, struct writeback_control *wbc); 570 extern int nfs_writepages(struct address_space *, struct writeback_control *); 571 extern int nfs_flush_incompatible(struct file *file, struct page *page); 572 extern int nfs_updatepage(struct file *, struct page *, unsigned int, unsigned int); 573 574 /* 575 * Try to write back everything synchronously (but check the 576 * return value!) 577 */ 578 extern int nfs_sync_inode(struct inode *inode); 579 extern int nfs_wb_all(struct inode *inode); 580 extern int nfs_wb_page(struct inode *inode, struct page *page); 581 int nfs_wb_folio_cancel(struct inode *inode, struct folio *folio); 582 extern int nfs_commit_inode(struct inode *, int); 583 extern struct nfs_commit_data *nfs_commitdata_alloc(void); 584 extern void nfs_commit_free(struct nfs_commit_data *data); 585 bool nfs_commit_end(struct nfs_mds_commit_info *cinfo); 586 587 static inline bool nfs_have_writebacks(const struct inode *inode) 588 { 589 if (S_ISREG(inode->i_mode)) 590 return atomic_long_read(&NFS_I(inode)->nrequests) != 0; 591 return false; 592 } 593 594 /* 595 * linux/fs/nfs/read.c 596 */ 597 extern int nfs_readpage(struct file *, struct page *); 598 void nfs_readahead(struct readahead_control *); 599 600 /* 601 * inline functions 602 */ 603 604 static inline loff_t nfs_size_to_loff_t(__u64 size) 605 { 606 return min_t(u64, size, OFFSET_MAX); 607 } 608 609 static inline ino_t 610 nfs_fileid_to_ino_t(u64 fileid) 611 { 612 ino_t ino = (ino_t) fileid; 613 if (sizeof(ino_t) < sizeof(u64)) 614 ino ^= fileid >> (sizeof(u64)-sizeof(ino_t)) * 8; 615 return ino; 616 } 617 618 #define NFS_JUKEBOX_RETRY_TIME (5 * HZ) 619 620 621 # undef ifdebug 622 # ifdef NFS_DEBUG 623 # define ifdebug(fac) if (unlikely(nfs_debug & NFSDBG_##fac)) 624 # define NFS_IFDEBUG(x) x 625 # else 626 # define ifdebug(fac) if (0) 627 # define NFS_IFDEBUG(x) 628 # endif 629 #endif 630