linux-stable/include/linux/nfs_fs.h
Greg Kroah-Hartman b24413180f License cleanup: add SPDX GPL-2.0 license identifier to files with no license
Many source files in the tree are missing licensing information, which
makes it harder for compliance tools to determine the correct license.

By default all files without license information are under the default
license of the kernel, which is GPL version 2.

Update the files which contain no license information with the 'GPL-2.0'
SPDX license identifier.  The SPDX identifier is a legally binding
shorthand, which can be used instead of the full boiler plate text.

This patch is based on work done by Thomas Gleixner and Kate Stewart and
Philippe Ombredanne.

How this work was done:

Patches were generated and checked against linux-4.14-rc6 for a subset of
the use cases:
 - file had no licensing information it it.
 - file was a */uapi/* one with no licensing information in it,
 - file was a */uapi/* one with existing licensing information,

Further patches will be generated in subsequent months to fix up cases
where non-standard license headers were used, and references to license
had to be inferred by heuristics based on keywords.

The analysis to determine which SPDX License Identifier to be applied to
a file was done in a spreadsheet of side by side results from of the
output of two independent scanners (ScanCode & Windriver) producing SPDX
tag:value files created by Philippe Ombredanne.  Philippe prepared the
base worksheet, and did an initial spot review of a few 1000 files.

The 4.13 kernel was the starting point of the analysis with 60,537 files
assessed.  Kate Stewart did a file by file comparison of the scanner
results in the spreadsheet to determine which SPDX license identifier(s)
to be applied to the file. She confirmed any determination that was not
immediately clear with lawyers working with the Linux Foundation.

Criteria used to select files for SPDX license identifier tagging was:
 - Files considered eligible had to be source code files.
 - Make and config files were included as candidates if they contained >5
   lines of source
 - File already had some variant of a license header in it (even if <5
   lines).

All documentation files were explicitly excluded.

The following heuristics were used to determine which SPDX license
identifiers to apply.

 - when both scanners couldn't find any license traces, file was
   considered to have no license information in it, and the top level
   COPYING file license applied.

   For non */uapi/* files that summary was:

   SPDX license identifier                            # files
   ---------------------------------------------------|-------
   GPL-2.0                                              11139

   and resulted in the first patch in this series.

   If that file was a */uapi/* path one, it was "GPL-2.0 WITH
   Linux-syscall-note" otherwise it was "GPL-2.0".  Results of that was:

   SPDX license identifier                            # files
   ---------------------------------------------------|-------
   GPL-2.0 WITH Linux-syscall-note                        930

   and resulted in the second patch in this series.

 - if a file had some form of licensing information in it, and was one
   of the */uapi/* ones, it was denoted with the Linux-syscall-note if
   any GPL family license was found in the file or had no licensing in
   it (per prior point).  Results summary:

   SPDX license identifier                            # files
   ---------------------------------------------------|------
   GPL-2.0 WITH Linux-syscall-note                       270
   GPL-2.0+ WITH Linux-syscall-note                      169
   ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause)    21
   ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause)    17
   LGPL-2.1+ WITH Linux-syscall-note                      15
   GPL-1.0+ WITH Linux-syscall-note                       14
   ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause)    5
   LGPL-2.0+ WITH Linux-syscall-note                       4
   LGPL-2.1 WITH Linux-syscall-note                        3
   ((GPL-2.0 WITH Linux-syscall-note) OR MIT)              3
   ((GPL-2.0 WITH Linux-syscall-note) AND MIT)             1

   and that resulted in the third patch in this series.

 - when the two scanners agreed on the detected license(s), that became
   the concluded license(s).

 - when there was disagreement between the two scanners (one detected a
   license but the other didn't, or they both detected different
   licenses) a manual inspection of the file occurred.

 - In most cases a manual inspection of the information in the file
   resulted in a clear resolution of the license that should apply (and
   which scanner probably needed to revisit its heuristics).

 - When it was not immediately clear, the license identifier was
   confirmed with lawyers working with the Linux Foundation.

 - If there was any question as to the appropriate license identifier,
   the file was flagged for further research and to be revisited later
   in time.

In total, over 70 hours of logged manual review was done on the
spreadsheet to determine the SPDX license identifiers to apply to the
source files by Kate, Philippe, Thomas and, in some cases, confirmation
by lawyers working with the Linux Foundation.

Kate also obtained a third independent scan of the 4.13 code base from
FOSSology, and compared selected files where the other two scanners
disagreed against that SPDX file, to see if there was new insights.  The
Windriver scanner is based on an older version of FOSSology in part, so
they are related.

Thomas did random spot checks in about 500 files from the spreadsheets
for the uapi headers and agreed with SPDX license identifier in the
files he inspected. For the non-uapi files Thomas did random spot checks
in about 15000 files.

In initial set of patches against 4.14-rc6, 3 files were found to have
copy/paste license identifier errors, and have been fixed to reflect the
correct identifier.

Additionally Philippe spent 10 hours this week doing a detailed manual
inspection and review of the 12,461 patched files from the initial patch
version early this week with:
 - a full scancode scan run, collecting the matched texts, detected
   license ids and scores
 - reviewing anything where there was a license detected (about 500+
   files) to ensure that the applied SPDX license was correct
 - reviewing anything where there was no detection but the patch license
   was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied
   SPDX license was correct

This produced a worksheet with 20 files needing minor correction.  This
worksheet was then exported into 3 different .csv files for the
different types of files to be modified.

These .csv files were then reviewed by Greg.  Thomas wrote a script to
parse the csv files and add the proper SPDX tag to the file, in the
format that the file expected.  This script was further refined by Greg
based on the output to detect more types of files automatically and to
distinguish between header and source .c files (which need different
comment types.)  Finally Greg ran the script using the .csv files to
generate the patches.

Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-11-02 11:10:55 +01:00

555 lines
16 KiB
C

/* SPDX-License-Identifier: GPL-2.0 */
/*
* linux/include/linux/nfs_fs.h
*
* Copyright (C) 1992 Rick Sladkey
*
* OS-specific nfs filesystem definitions and declarations
*/
#ifndef _LINUX_NFS_FS_H
#define _LINUX_NFS_FS_H
#include <uapi/linux/nfs_fs.h>
/*
* Enable dprintk() debugging support for nfs client.
*/
#ifdef CONFIG_NFS_DEBUG
# define NFS_DEBUG
#endif
#include <linux/in.h>
#include <linux/mm.h>
#include <linux/pagemap.h>
#include <linux/rbtree.h>
#include <linux/rwsem.h>
#include <linux/wait.h>
#include <linux/sunrpc/debug.h>
#include <linux/sunrpc/auth.h>
#include <linux/sunrpc/clnt.h>
#include <linux/nfs.h>
#include <linux/nfs2.h>
#include <linux/nfs3.h>
#include <linux/nfs4.h>
#include <linux/nfs_xdr.h>
#include <linux/nfs_fs_sb.h>
#include <linux/mempool.h>
/*
* These are the default flags for swap requests
*/
#define NFS_RPC_SWAPFLAGS (RPC_TASK_SWAPPER|RPC_TASK_ROOTCREDS)
/*
* NFSv3/v4 Access mode cache entry
*/
struct nfs_access_entry {
struct rb_node rb_node;
struct list_head lru;
struct rpc_cred * cred;
__u32 mask;
struct rcu_head rcu_head;
};
struct nfs_lock_context {
atomic_t count;
struct list_head list;
struct nfs_open_context *open_context;
fl_owner_t lockowner;
atomic_t io_count;
};
struct nfs4_state;
struct nfs_open_context {
struct nfs_lock_context lock_context;
fl_owner_t flock_owner;
struct dentry *dentry;
struct rpc_cred *cred;
struct nfs4_state *state;
fmode_t mode;
unsigned long flags;
#define NFS_CONTEXT_ERROR_WRITE (0)
#define NFS_CONTEXT_RESEND_WRITES (1)
#define NFS_CONTEXT_BAD (2)
#define NFS_CONTEXT_UNLOCK (3)
int error;
struct list_head list;
struct nfs4_threshold *mdsthreshold;
};
struct nfs_open_dir_context {
struct list_head list;
struct rpc_cred *cred;
unsigned long attr_gencount;
__u64 dir_cookie;
__u64 dup_cookie;
signed char duped;
};
/*
* NFSv4 delegation
*/
struct nfs_delegation;
struct posix_acl;
/*
* nfs fs inode data in memory
*/
struct nfs_inode {
/*
* The 64bit 'inode number'
*/
__u64 fileid;
/*
* NFS file handle
*/
struct nfs_fh fh;
/*
* Various flags
*/
unsigned long flags; /* atomic bit ops */
unsigned long cache_validity; /* bit mask */
/*
* read_cache_jiffies is when we started read-caching this inode.
* attrtimeo is for how long the cached information is assumed
* to be valid. A successful attribute revalidation doubles
* attrtimeo (up to acregmax/acdirmax), a failure resets it to
* acregmin/acdirmin.
*
* We need to revalidate the cached attrs for this inode if
*
* jiffies - read_cache_jiffies >= attrtimeo
*
* Please note the comparison is greater than or equal
* so that zero timeout values can be specified.
*/
unsigned long read_cache_jiffies;
unsigned long attrtimeo;
unsigned long attrtimeo_timestamp;
unsigned long attr_gencount;
/* "Generation counter" for the attribute cache. This is
* bumped whenever we update the metadata on the
* server.
*/
unsigned long cache_change_attribute;
struct rb_root access_cache;
struct list_head access_cache_entry_lru;
struct list_head access_cache_inode_lru;
/*
* This is the cookie verifier used for NFSv3 readdir
* operations
*/
__be32 cookieverf[2];
atomic_long_t nrequests;
struct nfs_mds_commit_info commit_info;
/* Open contexts for shared mmap writes */
struct list_head open_files;
/* Readers: in-flight sillydelete RPC calls */
/* Writers: rmdir */
struct rw_semaphore rmdir_sem;
struct mutex commit_mutex;
#if IS_ENABLED(CONFIG_NFS_V4)
struct nfs4_cached_acl *nfs4_acl;
/* NFSv4 state */
struct list_head open_states;
struct nfs_delegation __rcu *delegation;
struct rw_semaphore rwsem;
/* pNFS layout information */
struct pnfs_layout_hdr *layout;
#endif /* CONFIG_NFS_V4*/
/* how many bytes have been written/read and how many bytes queued up */
__u64 write_io;
__u64 read_io;
#ifdef CONFIG_NFS_FSCACHE
struct fscache_cookie *fscache;
#endif
struct inode vfs_inode;
};
/*
* Cache validity bit flags
*/
#define NFS_INO_INVALID_ATTR 0x0001 /* cached attrs are invalid */
#define NFS_INO_INVALID_DATA 0x0002 /* cached data is invalid */
#define NFS_INO_INVALID_ATIME 0x0004 /* cached atime is invalid */
#define NFS_INO_INVALID_ACCESS 0x0008 /* cached access cred invalid */
#define NFS_INO_INVALID_ACL 0x0010 /* cached acls are invalid */
#define NFS_INO_REVAL_PAGECACHE 0x0020 /* must revalidate pagecache */
#define NFS_INO_REVAL_FORCED 0x0040 /* force revalidation ignoring a delegation */
#define NFS_INO_INVALID_LABEL 0x0080 /* cached label is invalid */
/*
* Bit offsets in flags field
*/
#define NFS_INO_ADVISE_RDPLUS (0) /* advise readdirplus */
#define NFS_INO_STALE (1) /* possible stale inode */
#define NFS_INO_ACL_LRU_SET (2) /* Inode is on the LRU list */
#define NFS_INO_INVALIDATING (3) /* inode is being invalidated */
#define NFS_INO_FSCACHE (5) /* inode can be cached by FS-Cache */
#define NFS_INO_FSCACHE_LOCK (6) /* FS-Cache cookie management lock */
#define NFS_INO_LAYOUTCOMMIT (9) /* layoutcommit required */
#define NFS_INO_LAYOUTCOMMITTING (10) /* layoutcommit inflight */
#define NFS_INO_LAYOUTSTATS (11) /* layoutstats inflight */
#define NFS_INO_ODIRECT (12) /* I/O setting is O_DIRECT */
static inline struct nfs_inode *NFS_I(const struct inode *inode)
{
return container_of(inode, struct nfs_inode, vfs_inode);
}
static inline struct nfs_server *NFS_SB(const struct super_block *s)
{
return (struct nfs_server *)(s->s_fs_info);
}
static inline struct nfs_fh *NFS_FH(const struct inode *inode)
{
return &NFS_I(inode)->fh;
}
static inline struct nfs_server *NFS_SERVER(const struct inode *inode)
{
return NFS_SB(inode->i_sb);
}
static inline struct rpc_clnt *NFS_CLIENT(const struct inode *inode)
{
return NFS_SERVER(inode)->client;
}
static inline const struct nfs_rpc_ops *NFS_PROTO(const struct inode *inode)
{
return NFS_SERVER(inode)->nfs_client->rpc_ops;
}
static inline unsigned NFS_MINATTRTIMEO(const struct inode *inode)
{
struct nfs_server *nfss = NFS_SERVER(inode);
return S_ISDIR(inode->i_mode) ? nfss->acdirmin : nfss->acregmin;
}
static inline unsigned NFS_MAXATTRTIMEO(const struct inode *inode)
{
struct nfs_server *nfss = NFS_SERVER(inode);
return S_ISDIR(inode->i_mode) ? nfss->acdirmax : nfss->acregmax;
}
static inline int NFS_STALE(const struct inode *inode)
{
return test_bit(NFS_INO_STALE, &NFS_I(inode)->flags);
}
static inline struct fscache_cookie *nfs_i_fscache(struct inode *inode)
{
#ifdef CONFIG_NFS_FSCACHE
return NFS_I(inode)->fscache;
#else
return NULL;
#endif
}
static inline __u64 NFS_FILEID(const struct inode *inode)
{
return NFS_I(inode)->fileid;
}
static inline void set_nfs_fileid(struct inode *inode, __u64 fileid)
{
NFS_I(inode)->fileid = fileid;
}
static inline void nfs_mark_for_revalidate(struct inode *inode)
{
struct nfs_inode *nfsi = NFS_I(inode);
spin_lock(&inode->i_lock);
nfsi->cache_validity |= NFS_INO_INVALID_ATTR |
NFS_INO_REVAL_PAGECACHE |
NFS_INO_INVALID_ACCESS |
NFS_INO_INVALID_ACL;
if (S_ISDIR(inode->i_mode))
nfsi->cache_validity |= NFS_INO_INVALID_DATA;
spin_unlock(&inode->i_lock);
}
static inline int nfs_server_capable(struct inode *inode, int cap)
{
return NFS_SERVER(inode)->caps & cap;
}
static inline void nfs_set_verifier(struct dentry * dentry, unsigned long verf)
{
dentry->d_time = verf;
}
/**
* nfs_save_change_attribute - Returns the inode attribute change cookie
* @dir - pointer to parent directory inode
* The "change attribute" is updated every time we finish an operation
* that will result in a metadata change on the server.
*/
static inline unsigned long nfs_save_change_attribute(struct inode *dir)
{
return NFS_I(dir)->cache_change_attribute;
}
/**
* nfs_verify_change_attribute - Detects NFS remote directory changes
* @dir - pointer to parent directory inode
* @chattr - previously saved change attribute
* Return "false" if the verifiers doesn't match the change attribute.
* This would usually indicate that the directory contents have changed on
* the server, and that any dentries need revalidating.
*/
static inline int nfs_verify_change_attribute(struct inode *dir, unsigned long chattr)
{
return chattr == NFS_I(dir)->cache_change_attribute;
}
/*
* linux/fs/nfs/inode.c
*/
extern int nfs_sync_mapping(struct address_space *mapping);
extern void nfs_zap_mapping(struct inode *inode, struct address_space *mapping);
extern void nfs_zap_caches(struct inode *);
extern void nfs_invalidate_atime(struct inode *);
extern struct inode *nfs_fhget(struct super_block *, struct nfs_fh *,
struct nfs_fattr *, struct nfs4_label *);
struct inode *nfs_ilookup(struct super_block *sb, struct nfs_fattr *, struct nfs_fh *);
extern int nfs_refresh_inode(struct inode *, struct nfs_fattr *);
extern int nfs_post_op_update_inode(struct inode *inode, struct nfs_fattr *fattr);
extern int nfs_post_op_update_inode_force_wcc(struct inode *inode, struct nfs_fattr *fattr);
extern int nfs_post_op_update_inode_force_wcc_locked(struct inode *inode, struct nfs_fattr *fattr);
extern int nfs_getattr(const struct path *, struct kstat *, u32, unsigned int);
extern void nfs_access_add_cache(struct inode *, struct nfs_access_entry *);
extern void nfs_access_set_mask(struct nfs_access_entry *, u32);
extern int nfs_permission(struct inode *, int);
extern int nfs_open(struct inode *, struct file *);
extern int nfs_attribute_cache_expired(struct inode *inode);
extern int nfs_revalidate_inode(struct nfs_server *server, struct inode *inode);
extern int __nfs_revalidate_inode(struct nfs_server *, struct inode *);
extern bool nfs_mapping_need_revalidate_inode(struct inode *inode);
extern int nfs_revalidate_mapping(struct inode *inode, struct address_space *mapping);
extern int nfs_revalidate_mapping_rcu(struct inode *inode);
extern int nfs_setattr(struct dentry *, struct iattr *);
extern void nfs_setattr_update_inode(struct inode *inode, struct iattr *attr, struct nfs_fattr *);
extern void nfs_setsecurity(struct inode *inode, struct nfs_fattr *fattr,
struct nfs4_label *label);
extern struct nfs_open_context *get_nfs_open_context(struct nfs_open_context *ctx);
extern void put_nfs_open_context(struct nfs_open_context *ctx);
extern struct nfs_open_context *nfs_find_open_context(struct inode *inode, struct rpc_cred *cred, fmode_t mode);
extern struct nfs_open_context *alloc_nfs_open_context(struct dentry *dentry, fmode_t f_mode, struct file *filp);
extern void nfs_inode_attach_open_context(struct nfs_open_context *ctx);
extern void nfs_file_set_open_context(struct file *filp, struct nfs_open_context *ctx);
extern void nfs_file_clear_open_context(struct file *flip);
extern struct nfs_lock_context *nfs_get_lock_context(struct nfs_open_context *ctx);
extern void nfs_put_lock_context(struct nfs_lock_context *l_ctx);
extern u64 nfs_compat_user_ino64(u64 fileid);
extern void nfs_fattr_init(struct nfs_fattr *fattr);
extern void nfs_fattr_set_barrier(struct nfs_fattr *fattr);
extern unsigned long nfs_inc_attr_generation_counter(void);
extern struct nfs_fattr *nfs_alloc_fattr(void);
static inline void nfs_free_fattr(const struct nfs_fattr *fattr)
{
kfree(fattr);
}
extern struct nfs_fh *nfs_alloc_fhandle(void);
static inline void nfs_free_fhandle(const struct nfs_fh *fh)
{
kfree(fh);
}
#ifdef NFS_DEBUG
extern u32 _nfs_display_fhandle_hash(const struct nfs_fh *fh);
static inline u32 nfs_display_fhandle_hash(const struct nfs_fh *fh)
{
return _nfs_display_fhandle_hash(fh);
}
extern void _nfs_display_fhandle(const struct nfs_fh *fh, const char *caption);
#define nfs_display_fhandle(fh, caption) \
do { \
if (unlikely(nfs_debug & NFSDBG_FACILITY)) \
_nfs_display_fhandle(fh, caption); \
} while (0)
#else
static inline u32 nfs_display_fhandle_hash(const struct nfs_fh *fh)
{
return 0;
}
static inline void nfs_display_fhandle(const struct nfs_fh *fh,
const char *caption)
{
}
#endif
/*
* linux/fs/nfs/nfsroot.c
*/
extern int nfs_root_data(char **root_device, char **root_data); /*__init*/
/* linux/net/ipv4/ipconfig.c: trims ip addr off front of name, too. */
extern __be32 root_nfs_parse_addr(char *name); /*__init*/
/*
* linux/fs/nfs/file.c
*/
extern const struct file_operations nfs_file_operations;
#if IS_ENABLED(CONFIG_NFS_V4)
extern const struct file_operations nfs4_file_operations;
#endif /* CONFIG_NFS_V4 */
extern const struct address_space_operations nfs_file_aops;
extern const struct address_space_operations nfs_dir_aops;
static inline struct nfs_open_context *nfs_file_open_context(struct file *filp)
{
return filp->private_data;
}
static inline struct rpc_cred *nfs_file_cred(struct file *file)
{
if (file != NULL) {
struct nfs_open_context *ctx =
nfs_file_open_context(file);
if (ctx)
return ctx->cred;
}
return NULL;
}
/*
* linux/fs/nfs/direct.c
*/
extern ssize_t nfs_direct_IO(struct kiocb *, struct iov_iter *);
extern ssize_t nfs_file_direct_read(struct kiocb *iocb,
struct iov_iter *iter);
extern ssize_t nfs_file_direct_write(struct kiocb *iocb,
struct iov_iter *iter);
/*
* linux/fs/nfs/dir.c
*/
extern const struct file_operations nfs_dir_operations;
extern const struct dentry_operations nfs_dentry_operations;
extern void nfs_force_lookup_revalidate(struct inode *dir);
extern int nfs_instantiate(struct dentry *dentry, struct nfs_fh *fh,
struct nfs_fattr *fattr, struct nfs4_label *label);
extern int nfs_may_open(struct inode *inode, struct rpc_cred *cred, int openflags);
extern void nfs_access_zap_cache(struct inode *inode);
/*
* linux/fs/nfs/symlink.c
*/
extern const struct inode_operations nfs_symlink_inode_operations;
/*
* linux/fs/nfs/sysctl.c
*/
#ifdef CONFIG_SYSCTL
extern int nfs_register_sysctl(void);
extern void nfs_unregister_sysctl(void);
#else
#define nfs_register_sysctl() 0
#define nfs_unregister_sysctl() do { } while(0)
#endif
/*
* linux/fs/nfs/namespace.c
*/
extern const struct inode_operations nfs_mountpoint_inode_operations;
extern const struct inode_operations nfs_referral_inode_operations;
extern int nfs_mountpoint_expiry_timeout;
extern void nfs_release_automount_timer(void);
/*
* linux/fs/nfs/unlink.c
*/
extern void nfs_complete_unlink(struct dentry *dentry, struct inode *);
/*
* linux/fs/nfs/write.c
*/
extern int nfs_congestion_kb;
extern int nfs_writepage(struct page *page, struct writeback_control *wbc);
extern int nfs_writepages(struct address_space *, struct writeback_control *);
extern int nfs_flush_incompatible(struct file *file, struct page *page);
extern int nfs_updatepage(struct file *, struct page *, unsigned int, unsigned int);
/*
* Try to write back everything synchronously (but check the
* return value!)
*/
extern int nfs_sync_inode(struct inode *inode);
extern int nfs_wb_all(struct inode *inode);
extern int nfs_wb_page(struct inode *inode, struct page *page);
extern int nfs_wb_page_cancel(struct inode *inode, struct page* page);
extern int nfs_commit_inode(struct inode *, int);
extern struct nfs_commit_data *nfs_commitdata_alloc(bool never_fail);
extern void nfs_commit_free(struct nfs_commit_data *data);
static inline int
nfs_have_writebacks(struct inode *inode)
{
return atomic_long_read(&NFS_I(inode)->nrequests) != 0;
}
/*
* linux/fs/nfs/read.c
*/
extern int nfs_readpage(struct file *, struct page *);
extern int nfs_readpages(struct file *, struct address_space *,
struct list_head *, unsigned);
extern int nfs_readpage_async(struct nfs_open_context *, struct inode *,
struct page *);
/*
* inline functions
*/
static inline loff_t nfs_size_to_loff_t(__u64 size)
{
return min_t(u64, size, OFFSET_MAX);
}
static inline ino_t
nfs_fileid_to_ino_t(u64 fileid)
{
ino_t ino = (ino_t) fileid;
if (sizeof(ino_t) < sizeof(u64))
ino ^= fileid >> (sizeof(u64)-sizeof(ino_t)) * 8;
return ino;
}
#define NFS_JUKEBOX_RETRY_TIME (5 * HZ)
# undef ifdebug
# ifdef NFS_DEBUG
# define ifdebug(fac) if (unlikely(nfs_debug & NFSDBG_##fac))
# define NFS_IFDEBUG(x) x
# else
# define ifdebug(fac) if (0)
# define NFS_IFDEBUG(x)
# endif
#endif