include/linux/nfs_fs.h

   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/magic.h>
  13
  14 /* Default timeout values */
  15 #define NFS_DEF_UDP_TIMEO       (11)
  16 #define NFS_DEF_UDP_RETRANS     (3)
  17 #define NFS_DEF_TCP_TIMEO       (600)
  18 #define NFS_DEF_TCP_RETRANS     (2)
  19
  20 #define NFS_MAX_UDP_TIMEOUT     (60*HZ)
  21 #define NFS_MAX_TCP_TIMEOUT     (600*HZ)
  22
  23 #define NFS_DEF_ACREGMIN        (3)
  24 #define NFS_DEF_ACREGMAX        (60)
  25 #define NFS_DEF_ACDIRMIN        (30)
  26 #define NFS_DEF_ACDIRMAX        (60)
  27
  28 /*
  29  * When flushing a cluster of dirty pages, there can be different
  30  * strategies:
  31  */
  32 #define FLUSH_SYNC              1       /* file being synced, or contention */
  33 #define FLUSH_STABLE            4       /* commit to stable storage */
  34 #define FLUSH_LOWPRI            8       /* low priority background flush */
  35 #define FLUSH_HIGHPRI           16      /* high priority memory reclaim flush */
  36 #define FLUSH_NOCOMMIT          32      /* Don't send the NFSv3/v4 COMMIT */
  37 #define FLUSH_INVALIDATE        64      /* Invalidate the page cache */
  38 #define FLUSH_NOWRITEPAGE       128     /* Don't call writepage() */
  39
  40 #ifdef __KERNEL__
  41
  42 #include <linux/in.h>
  43 #include <linux/kref.h>
  44 #include <linux/mm.h>
  45 #include <linux/pagemap.h>
  46 #include <linux/rbtree.h>
  47 #include <linux/rwsem.h>
  48 #include <linux/wait.h>
  49
  50 #include <linux/sunrpc/debug.h>
  51 #include <linux/sunrpc/auth.h>
  52 #include <linux/sunrpc/clnt.h>
  53
  54 #include <linux/nfs.h>
  55 #include <linux/nfs2.h>
  56 #include <linux/nfs3.h>
  57 #include <linux/nfs4.h>
  58 #include <linux/nfs_xdr.h>
  59 #include <linux/nfs_fs_sb.h>
  60
  61 #include <linux/mempool.h>
  62
  63 /*
  64  * These are the default flags for swap requests
  65  */
  66 #define NFS_RPC_SWAPFLAGS               (RPC_TASK_SWAPPER|RPC_TASK_ROOTCREDS)
  67
  68 /*
  69  * NFSv3/v4 Access mode cache entry
  70  */
  71 struct nfs_access_entry {
  72         struct rb_node          rb_node;
  73         struct list_head        lru;
  74         unsigned long           jiffies;
  75         struct rpc_cred *       cred;
  76         int                     mask;
  77 };
  78
  79 struct nfs4_state;
  80 struct nfs_open_context {
  81         atomic_t count;
  82         struct path path;
  83         struct rpc_cred *cred;
  84         struct nfs4_state *state;
  85         fl_owner_t lockowner;
  86         fmode_t mode;
  87
  88         unsigned long flags;
  89 #define NFS_CONTEXT_ERROR_WRITE         (0)
  90         int error;
  91
  92         struct list_head list;
  93
  94         __u64 dir_cookie;
  95 };
  96
  97 /*
  98  * NFSv4 delegation
  99  */
 100 struct nfs_delegation;
 101
 102 struct posix_acl;
 103
 104 /*
 105  * nfs fs inode data in memory
 106  */
 107 struct nfs_inode {
 108         /*
 109          * The 64bit 'inode number'
 110          */
 111         __u64 fileid;
 112
 113         /*
 114          * NFS file handle
 115          */
 116         struct nfs_fh           fh;
 117
 118         /*
 119          * Various flags
 120          */
 121         unsigned long           flags;                  /* atomic bit ops */
 122         unsigned long           cache_validity;         /* bit mask */
 123
 124         /*
 125          * read_cache_jiffies is when we started read-caching this inode.
 126          * attrtimeo is for how long the cached information is assumed
 127          * to be valid. A successful attribute revalidation doubles
 128          * attrtimeo (up to acregmax/acdirmax), a failure resets it to
 129          * acregmin/acdirmin.
 130          *
 131          * We need to revalidate the cached attrs for this inode if
 132          *
 133          *      jiffies - read_cache_jiffies >= attrtimeo
 134          *
 135          * Please note the comparison is greater than or equal
 136          * so that zero timeout values can be specified.
 137          */
 138         unsigned long           read_cache_jiffies;
 139         unsigned long           attrtimeo;
 140         unsigned long           attrtimeo_timestamp;
 141         __u64                   change_attr;            /* v4 only */
 142
 143         unsigned long           attr_gencount;
 144         /* "Generation counter" for the attribute cache. This is
 145          * bumped whenever we update the metadata on the
 146          * server.
 147          */
 148         unsigned long           cache_change_attribute;
 149
 150         struct rb_root          access_cache;
 151         struct list_head        access_cache_entry_lru;
 152         struct list_head        access_cache_inode_lru;
 153 #ifdef CONFIG_NFS_V3_ACL
 154         struct posix_acl        *acl_access;
 155         struct posix_acl        *acl_default;
 156 #endif
 157
 158         /*
 159          * This is the cookie verifier used for NFSv3 readdir
 160          * operations
 161          */
 162         __be32                  cookieverf[2];
 163
 164         /*
 165          * This is the list of dirty unwritten pages.
 166          */
 167         struct radix_tree_root  nfs_page_tree;
 168
 169         unsigned long           npages;
 170
 171         /* Open contexts for shared mmap writes */
 172         struct list_head        open_files;
 173
 174         /* Number of in-flight sillydelete RPC calls */
 175         atomic_t                silly_count;
 176         /* List of deferred sillydelete requests */
 177         struct hlist_head       silly_list;
 178         wait_queue_head_t       waitqueue;
 179
 180 #ifdef CONFIG_NFS_V4
 181         struct nfs4_cached_acl  *nfs4_acl;
 182         /* NFSv4 state */
 183         struct list_head        open_states;
 184         struct nfs_delegation   *delegation;
 185         fmode_t                  delegation_state;
 186         struct rw_semaphore     rwsem;
 187 #endif /* CONFIG_NFS_V4*/
 188 #ifdef CONFIG_NFS_FSCACHE
 189         struct fscache_cookie   *fscache;
 190 #endif
 191         struct inode            vfs_inode;
 192 };
 193
 194 /*
 195  * Cache validity bit flags
 196  */
 197 #define NFS_INO_INVALID_ATTR    0x0001          /* cached attrs are invalid */
 198 #define NFS_INO_INVALID_DATA    0x0002          /* cached data is invalid */
 199 #define NFS_INO_INVALID_ATIME   0x0004          /* cached atime is invalid */
 200 #define NFS_INO_INVALID_ACCESS  0x0008          /* cached access cred invalid */
 201 #define NFS_INO_INVALID_ACL     0x0010          /* cached acls are invalid */
 202 #define NFS_INO_REVAL_PAGECACHE 0x0020          /* must revalidate pagecache */
 203 #define NFS_INO_REVAL_FORCED    0x0040          /* force revalidation ignoring a delegation */
 204
 205 /*
 206  * Bit offsets in flags field
 207  */
 208 #define NFS_INO_ADVISE_RDPLUS   (0)             /* advise readdirplus */
 209 #define NFS_INO_STALE           (1)             /* possible stale inode */
 210 #define NFS_INO_ACL_LRU_SET     (2)             /* Inode is on the LRU list */
 211 #define NFS_INO_MOUNTPOINT      (3)             /* inode is remote mountpoint */
 212 #define NFS_INO_FLUSHING        (4)             /* inode is flushing out data */
 213 #define NFS_INO_FSCACHE         (5)             /* inode can be cached by FS-Cache */
 214 #define NFS_INO_FSCACHE_LOCK    (6)             /* FS-Cache cookie management lock */
 215
 216 static inline struct nfs_inode *NFS_I(const struct inode *inode)
 217 {
 218         return container_of(inode, struct nfs_inode, vfs_inode);
 219 }
 220
 221 static inline struct nfs_server *NFS_SB(const struct super_block *s)
 222 {
 223         return (struct nfs_server *)(s->s_fs_info);
 224 }
 225
 226 static inline struct nfs_fh *NFS_FH(const struct inode *inode)
 227 {
 228         return &NFS_I(inode)->fh;
 229 }
 230
 231 static inline struct nfs_server *NFS_SERVER(const struct inode *inode)
 232 {
 233         return NFS_SB(inode->i_sb);
 234 }
 235
 236 static inline struct rpc_clnt *NFS_CLIENT(const struct inode *inode)
 237 {
 238         return NFS_SERVER(inode)->client;
 239 }
 240
 241 static inline const struct nfs_rpc_ops *NFS_PROTO(const struct inode *inode)
 242 {
 243         return NFS_SERVER(inode)->nfs_client->rpc_ops;
 244 }
 245
 246 static inline __be32 *NFS_COOKIEVERF(const struct inode *inode)
 247 {
 248         return NFS_I(inode)->cookieverf;
 249 }
 250
 251 static inline unsigned NFS_MINATTRTIMEO(const struct inode *inode)
 252 {
 253         struct nfs_server *nfss = NFS_SERVER(inode);
 254         return S_ISDIR(inode->i_mode) ? nfss->acdirmin : nfss->acregmin;
 255 }
 256
 257 static inline unsigned NFS_MAXATTRTIMEO(const struct inode *inode)
 258 {
 259         struct nfs_server *nfss = NFS_SERVER(inode);
 260         return S_ISDIR(inode->i_mode) ? nfss->acdirmax : nfss->acregmax;
 261 }
 262
 263 static inline int NFS_STALE(const struct inode *inode)
 264 {
 265         return test_bit(NFS_INO_STALE, &NFS_I(inode)->flags);
 266 }
 267
 268 static inline int NFS_FSCACHE(const struct inode *inode)
 269 {
 270         return test_bit(NFS_INO_FSCACHE, &NFS_I(inode)->flags);
 271 }
 272
 273 static inline __u64 NFS_FILEID(const struct inode *inode)
 274 {
 275         return NFS_I(inode)->fileid;
 276 }
 277
 278 static inline void set_nfs_fileid(struct inode *inode, __u64 fileid)
 279 {
 280         NFS_I(inode)->fileid = fileid;
 281 }
 282
 283 static inline void nfs_mark_for_revalidate(struct inode *inode)
 284 {
 285         struct nfs_inode *nfsi = NFS_I(inode);
 286
 287         spin_lock(&inode->i_lock);
 288         nfsi->cache_validity |= NFS_INO_INVALID_ATTR|NFS_INO_INVALID_ACCESS;
 289         if (S_ISDIR(inode->i_mode))
 290                 nfsi->cache_validity |= NFS_INO_REVAL_PAGECACHE|NFS_INO_INVALID_DATA;
 291         spin_unlock(&inode->i_lock);
 292 }
 293
 294 static inline int nfs_server_capable(struct inode *inode, int cap)
 295 {
 296         return NFS_SERVER(inode)->caps & cap;
 297 }
 298
 299 static inline int NFS_USE_READDIRPLUS(struct inode *inode)
 300 {
 301         return test_bit(NFS_INO_ADVISE_RDPLUS, &NFS_I(inode)->flags);
 302 }
 303
 304 static inline void nfs_set_verifier(struct dentry * dentry, unsigned long verf)
 305 {
 306         dentry->d_time = verf;
 307 }
 308
 309 /**
 310  * nfs_save_change_attribute - Returns the inode attribute change cookie
 311  * @dir - pointer to parent directory inode
 312  * The "change attribute" is updated every time we finish an operation
 313  * that will result in a metadata change on the server.
 314  */
 315 static inline unsigned long nfs_save_change_attribute(struct inode *dir)
 316 {
 317         return NFS_I(dir)->cache_change_attribute;
 318 }
 319
 320 /**
 321  * nfs_verify_change_attribute - Detects NFS remote directory changes
 322  * @dir - pointer to parent directory inode
 323  * @chattr - previously saved change attribute
 324  * Return "false" if the verifiers doesn't match the change attribute.
 325  * This would usually indicate that the directory contents have changed on
 326  * the server, and that any dentries need revalidating.
 327  */
 328 static inline int nfs_verify_change_attribute(struct inode *dir, unsigned long chattr)
 329 {
 330         return chattr == NFS_I(dir)->cache_change_attribute;
 331 }
 332
 333 /*
 334  * linux/fs/nfs/inode.c
 335  */
 336 extern int nfs_sync_mapping(struct address_space *mapping);
 337 extern void nfs_zap_mapping(struct inode *inode, struct address_space *mapping);
 338 extern void nfs_zap_caches(struct inode *);
 339 extern void nfs_invalidate_atime(struct inode *);
 340 extern struct inode *nfs_fhget(struct super_block *, struct nfs_fh *,
 341                                 struct nfs_fattr *);
 342 extern int nfs_refresh_inode(struct inode *, struct nfs_fattr *);
 343 extern int nfs_post_op_update_inode(struct inode *inode, struct nfs_fattr *fattr);
 344 extern int nfs_post_op_update_inode_force_wcc(struct inode *inode, struct nfs_fattr *fattr);
 345 extern int nfs_getattr(struct vfsmount *, struct dentry *, struct kstat *);
 346 extern int nfs_permission(struct inode *, int);
 347 extern int nfs_open(struct inode *, struct file *);
 348 extern int nfs_release(struct inode *, struct file *);
 349 extern int nfs_attribute_timeout(struct inode *inode);
 350 extern int nfs_revalidate_inode(struct nfs_server *server, struct inode *inode);
 351 extern int __nfs_revalidate_inode(struct nfs_server *, struct inode *);
 352 extern int nfs_revalidate_mapping(struct inode *inode, struct address_space *mapping);
 353 extern int nfs_revalidate_mapping_nolock(struct inode *inode, struct address_space *mapping);
 354 extern int nfs_setattr(struct dentry *, struct iattr *);
 355 extern void nfs_setattr_update_inode(struct inode *inode, struct iattr *attr);
 356 extern struct nfs_open_context *get_nfs_open_context(struct nfs_open_context *ctx);
 357 extern void put_nfs_open_context(struct nfs_open_context *ctx);
 358 extern struct nfs_open_context *nfs_find_open_context(struct inode *inode, struct rpc_cred *cred, fmode_t mode);
 359 extern u64 nfs_compat_user_ino64(u64 fileid);
 360 extern void nfs_fattr_init(struct nfs_fattr *fattr);
 361
 362 /* linux/net/ipv4/ipconfig.c: trims ip addr off front of name, too. */
 363 extern __be32 root_nfs_parse_addr(char *name); /*__init*/
 364 extern unsigned long nfs_inc_attr_generation_counter(void);
 365
 366 /*
 367  * linux/fs/nfs/file.c
 368  */
 369 extern const struct inode_operations nfs_file_inode_operations;
 370 #ifdef CONFIG_NFS_V3
 371 extern const struct inode_operations nfs3_file_inode_operations;
 372 #endif /* CONFIG_NFS_V3 */
 373 extern const struct file_operations nfs_file_operations;
 374 extern const struct address_space_operations nfs_file_aops;
 375
 376 static inline struct nfs_open_context *nfs_file_open_context(struct file *filp)
 377 {
 378         return filp->private_data;
 379 }
 380
 381 static inline struct rpc_cred *nfs_file_cred(struct file *file)
 382 {
 383         if (file != NULL) {
 384                 struct nfs_open_context *ctx =
 385                         nfs_file_open_context(file);
 386                 if (ctx)
 387                         return ctx->cred;
 388         }
 389         return NULL;
 390 }
 391
 392 /*
 393  * linux/fs/nfs/xattr.c
 394  */
 395 #ifdef CONFIG_NFS_V3_ACL
 396 extern ssize_t nfs3_listxattr(struct dentry *, char *, size_t);
 397 extern ssize_t nfs3_getxattr(struct dentry *, const char *, void *, size_t);
 398 extern int nfs3_setxattr(struct dentry *, const char *,
 399                         const void *, size_t, int);
 400 extern int nfs3_removexattr (struct dentry *, const char *name);
 401 #else
 402 # define nfs3_listxattr NULL
 403 # define nfs3_getxattr NULL
 404 # define nfs3_setxattr NULL
 405 # define nfs3_removexattr NULL
 406 #endif
 407
 408 /*
 409  * linux/fs/nfs/direct.c
 410  */
 411 extern ssize_t nfs_direct_IO(int, struct kiocb *, const struct iovec *, loff_t,
 412                         unsigned long);
 413 extern ssize_t nfs_file_direct_read(struct kiocb *iocb,
 414                         const struct iovec *iov, unsigned long nr_segs,
 415                         loff_t pos);
 416 extern ssize_t nfs_file_direct_write(struct kiocb *iocb,
 417                         const struct iovec *iov, unsigned long nr_segs,
 418                         loff_t pos);
 419
 420 /*
 421  * linux/fs/nfs/dir.c
 422  */
 423 extern const struct inode_operations nfs_dir_inode_operations;
 424 #ifdef CONFIG_NFS_V3
 425 extern const struct inode_operations nfs3_dir_inode_operations;
 426 #endif /* CONFIG_NFS_V3 */
 427 extern const struct file_operations nfs_dir_operations;
 428 extern const struct dentry_operations nfs_dentry_operations;
 429
 430 extern void nfs_force_lookup_revalidate(struct inode *dir);
 431 extern int nfs_instantiate(struct dentry *dentry, struct nfs_fh *fh, struct nfs_fattr *fattr);
 432 extern int nfs_may_open(struct inode *inode, struct rpc_cred *cred, int openflags);
 433 extern void nfs_access_zap_cache(struct inode *inode);
 434
 435 /*
 436  * linux/fs/nfs/symlink.c
 437  */
 438 extern const struct inode_operations nfs_symlink_inode_operations;
 439
 440 /*
 441  * linux/fs/nfs/sysctl.c
 442  */
 443 #ifdef CONFIG_SYSCTL
 444 extern int nfs_register_sysctl(void);
 445 extern void nfs_unregister_sysctl(void);
 446 #else
 447 #define nfs_register_sysctl() 0
 448 #define nfs_unregister_sysctl() do { } while(0)
 449 #endif
 450
 451 /*
 452  * linux/fs/nfs/namespace.c
 453  */
 454 extern const struct inode_operations nfs_mountpoint_inode_operations;
 455 extern const struct inode_operations nfs_referral_inode_operations;
 456 extern int nfs_mountpoint_expiry_timeout;
 457 extern void nfs_release_automount_timer(void);
 458
 459 /*
 460  * linux/fs/nfs/unlink.c
 461  */
 462 extern int  nfs_async_unlink(struct inode *dir, struct dentry *dentry);
 463 extern void nfs_complete_unlink(struct dentry *dentry, struct inode *);
 464 extern void nfs_block_sillyrename(struct dentry *dentry);
 465 extern void nfs_unblock_sillyrename(struct dentry *dentry);
 466
 467 /*
 468  * linux/fs/nfs/write.c
 469  */
 470 extern int  nfs_congestion_kb;
 471 extern int  nfs_writepage(struct page *page, struct writeback_control *wbc);
 472 extern int  nfs_writepages(struct address_space *, struct writeback_control *);
 473 extern int  nfs_flush_incompatible(struct file *file, struct page *page);
 474 extern int  nfs_updatepage(struct file *, struct page *, unsigned int, unsigned int);
 475 extern int nfs_writeback_done(struct rpc_task *, struct nfs_write_data *);
 476
 477 /*
 478  * Try to write back everything synchronously (but check the
 479  * return value!)
 480  */
 481 extern long nfs_sync_mapping_wait(struct address_space *, struct writeback_control *, int);
 482 extern int nfs_wb_all(struct inode *inode);
 483 extern int nfs_wb_nocommit(struct inode *inode);
 484 extern int nfs_wb_page(struct inode *inode, struct page* page);
 485 extern int nfs_wb_page_cancel(struct inode *inode, struct page* page);
 486 #if defined(CONFIG_NFS_V3) || defined(CONFIG_NFS_V4)
 487 extern int  nfs_commit_inode(struct inode *, int);
 488 extern struct nfs_write_data *nfs_commitdata_alloc(void);
 489 extern void nfs_commit_free(struct nfs_write_data *wdata);
 490 #else
 491 static inline int
 492 nfs_commit_inode(struct inode *inode, int how)
 493 {
 494         return 0;
 495 }
 496 #endif
 497
 498 static inline int
 499 nfs_have_writebacks(struct inode *inode)
 500 {
 501         return NFS_I(inode)->npages != 0;
 502 }
 503
 504 /*
 505  * Allocate nfs_write_data structures
 506  */
 507 extern struct nfs_write_data *nfs_writedata_alloc(unsigned int npages);
 508 extern void nfs_writedata_free(struct nfs_write_data *);
 509
 510 /*
 511  * linux/fs/nfs/read.c
 512  */
 513 extern int  nfs_readpage(struct file *, struct page *);
 514 extern int  nfs_readpages(struct file *, struct address_space *,
 515                 struct list_head *, unsigned);
 516 extern int  nfs_readpage_result(struct rpc_task *, struct nfs_read_data *);
 517 extern int  nfs_readpage_async(struct nfs_open_context *, struct inode *,
 518                                struct page *);
 519
 520 /*
 521  * Allocate nfs_read_data structures
 522  */
 523 extern struct nfs_read_data *nfs_readdata_alloc(unsigned int npages);
 524 extern void nfs_readdata_free(struct nfs_read_data *);
 525
 526 /*
 527  * linux/fs/nfs3proc.c
 528  */
 529 #ifdef CONFIG_NFS_V3_ACL
 530 extern struct posix_acl *nfs3_proc_getacl(struct inode *inode, int type);
 531 extern int nfs3_proc_setacl(struct inode *inode, int type,
 532                             struct posix_acl *acl);
 533 extern int nfs3_proc_set_default_acl(struct inode *dir, struct inode *inode,
 534                 mode_t mode);
 535 extern void nfs3_forget_cached_acls(struct inode *inode);
 536 #else
 537 static inline int nfs3_proc_set_default_acl(struct inode *dir,
 538                                             struct inode *inode,
 539                                             mode_t mode)
 540 {
 541         return 0;
 542 }
 543
 544 static inline void nfs3_forget_cached_acls(struct inode *inode)
 545 {
 546 }
 547 #endif /* CONFIG_NFS_V3_ACL */
 548
 549 /*
 550  * inline functions
 551  */
 552
 553 static inline loff_t nfs_size_to_loff_t(__u64 size)
 554 {
 555         if (size > (__u64) OFFSET_MAX - 1)
 556                 return OFFSET_MAX - 1;
 557         return (loff_t) size;
 558 }
 559
 560 static inline ino_t
 561 nfs_fileid_to_ino_t(u64 fileid)
 562 {
 563         ino_t ino = (ino_t) fileid;
 564         if (sizeof(ino_t) < sizeof(u64))
 565                 ino ^= fileid >> (sizeof(u64)-sizeof(ino_t)) * 8;
 566         return ino;
 567 }
 568
 569 /* NFS root */
 570
 571 extern void * nfs_root_data(void);
 572
 573 #define nfs_wait_event(clnt, wq, condition)                             \
 574 ({                                                                      \
 575         int __retval = wait_event_killable(wq, condition);              \
 576         __retval;                                                       \
 577 })
 578
 579 #define NFS_JUKEBOX_RETRY_TIME (5 * HZ)
 580
 581 #endif /* __KERNEL__ */
 582
 583 /*
 584  * NFS debug flags
 585  */
 586 #define NFSDBG_VFS              0x0001
 587 #define NFSDBG_DIRCACHE         0x0002
 588 #define NFSDBG_LOOKUPCACHE      0x0004
 589 #define NFSDBG_PAGECACHE        0x0008
 590 #define NFSDBG_PROC             0x0010
 591 #define NFSDBG_XDR              0x0020
 592 #define NFSDBG_FILE             0x0040
 593 #define NFSDBG_ROOT             0x0080
 594 #define NFSDBG_CALLBACK         0x0100
 595 #define NFSDBG_CLIENT           0x0200
 596 #define NFSDBG_MOUNT            0x0400
 597 #define NFSDBG_FSCACHE          0x0800
 598 #define NFSDBG_ALL              0xFFFF
 599
 600 #ifdef __KERNEL__
 601
 602 /*
 603  * Enable debugging support for nfs client.
 604  * Requires RPC_DEBUG.
 605  */
 606 #ifdef RPC_DEBUG
 607 # define NFS_DEBUG
 608 #endif
 609
 610 # undef ifdebug
 611 # ifdef NFS_DEBUG
 612 #  define ifdebug(fac)          if (unlikely(nfs_debug & NFSDBG_##fac))
 613 # else
 614 #  define ifdebug(fac)          if (0)
 615 # endif
 616 #endif /* __KERNEL */
 617
 618 #endif