/*
 *  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 <linux/config.h>
#include <linux/in.h>
#include <linux/mm.h>
#include <linux/pagemap.h>
#include <linux/wait.h>

#include <linux/nfs_fs_sb.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/nfs_xdr.h>

/*
 * Enable debugging support for nfs client.
 * Requires RPC_DEBUG.
 */
#ifdef RPC_DEBUG
# define NFS_DEBUG
#endif

/*
 * NFS_MAX_DIRCACHE controls the number of simultaneously cached
 * directory chunks. Each chunk holds the list of nfs_entry's returned
 * in a single readdir call in a memory region of size PAGE_SIZE.
 *
 * Note that at most server->rsize bytes of the cache memory are used.
 */
#define NFS_MAX_DIRCACHE		16

#define NFS_MAX_FILE_IO_BUFFER_SIZE	32768
#define NFS_DEF_FILE_IO_BUFFER_SIZE	4096

/*
 * The upper limit on timeouts for the exponential backoff algorithm.
 */
#define NFS_MAX_RPC_TIMEOUT		(6*HZ)
#define NFS_READ_DELAY			(2*HZ)
#define NFS_WRITEBACK_DELAY		(5*HZ)
#define NFS_WRITEBACK_LOCKDELAY		(60*HZ)
#define NFS_COMMIT_DELAY		(5*HZ)

/*
 * Size of the lookup cache in units of number of entries cached.
 * It is better not to make this too large although the optimum
 * depends on a usage and environment.
 */
#define NFS_LOOKUP_CACHE_SIZE		64

/*
 * superblock magic number for NFS
 */
#define NFS_SUPER_MAGIC			0x6969

/*
 * These are the default flags for swap requests
 */
#define NFS_RPC_SWAPFLAGS		(RPC_TASK_SWAPPER|RPC_TASK_ROOTCREDS)

/* Flags in the RPC client structure */
#define NFS_CLNTF_BUFSIZE	0x0001	/* readdir buffer in longwords */

#define NFS_RW_SYNC		0x0001	/* O_SYNC handling */
#define NFS_RW_SWAP		0x0002	/* This is a swap request */

/*
 * When flushing a cluster of dirty pages, there can be different
 * strategies:
 */
#define FLUSH_AGING		0	/* only flush old buffers */
#define FLUSH_SYNC		1	/* file being synced, or contention */
#define FLUSH_WAIT		2	/* wait for completion */
#define FLUSH_STABLE		4	/* commit to stable storage */

#ifdef __KERNEL__

/*
 * 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 short		flags;

	/*
	 * read_cache_jiffies is when we started read-caching this inode,
	 * and read_cache_mtime is the mtime of the inode at that time.
	 * 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
	 *
	 * and invalidate any cached data/flush out any dirty pages if
	 * we find that
	 *
	 *	mtime != read_cache_mtime
	 */
	unsigned long		read_cache_jiffies;
	__u64			read_cache_ctime;
	__u64			read_cache_mtime;
	__u64			read_cache_isize;
	unsigned long		attrtimeo;
	unsigned long		attrtimeo_timestamp;

	/*
	 * Timestamp that dates the change made to read_cache_mtime.
	 * This is of use for dentry revalidation
	 */
	unsigned long		cache_mtime_jiffies;

	/*
	 * This is the cookie verifier used for NFSv3 readdir
	 * operations
	 */
	__u32			cookieverf[2];

	/*
	 * This is the list of dirty unwritten pages.
	 */
	struct list_head	read;
	struct list_head	dirty;
	struct list_head	commit;
	struct list_head	writeback;

	unsigned int		nread,
				ndirty,
				ncommit,
				npages;

	/* Credentials for shared mmap */
	struct rpc_cred		*mm_cred;

	wait_queue_head_t	nfs_i_wait;

	struct inode		vfs_inode;
};

/*
 * Legal inode flag values
 */
#define NFS_INO_STALE		0x0001		/* possible stale inode */
#define NFS_INO_ADVISE_RDPLUS   0x0002          /* advise readdirplus */
#define NFS_INO_REVALIDATING	0x0004		/* revalidating attrs */
#define NFS_IS_SNAPSHOT		0x0010		/* a snapshot file */
#define NFS_INO_FLUSH		0x0020		/* inode is due for flushing */

static inline struct nfs_inode *NFS_I(struct inode *inode)
{
	return list_entry(inode, struct nfs_inode, vfs_inode);
}
#define NFS_SB(s)		((struct nfs_server *)(s->u.generic_sbp))

#define NFS_FH(inode)			(&NFS_I(inode)->fh)
#define NFS_SERVER(inode)		(NFS_SB(inode->i_sb))
#define NFS_CLIENT(inode)		(NFS_SERVER(inode)->client)
#define NFS_PROTO(inode)		(NFS_SERVER(inode)->rpc_ops)
#define NFS_REQUESTLIST(inode)		(NFS_SERVER(inode)->rw_requests)
#define NFS_ADDR(inode)			(RPC_PEERADDR(NFS_CLIENT(inode)))
#define NFS_CONGESTED(inode)		(RPC_CONGESTED(NFS_CLIENT(inode)))
#define NFS_COOKIEVERF(inode)		(NFS_I(inode)->cookieverf)
#define NFS_READTIME(inode)		(NFS_I(inode)->read_cache_jiffies)
#define NFS_MTIME_UPDATE(inode)		(NFS_I(inode)->cache_mtime_jiffies)
#define NFS_CACHE_CTIME(inode)		(NFS_I(inode)->read_cache_ctime)
#define NFS_CACHE_MTIME(inode)		(NFS_I(inode)->read_cache_mtime)
#define NFS_CACHE_ISIZE(inode)		(NFS_I(inode)->read_cache_isize)
#define NFS_NEXTSCAN(inode)		(NFS_I(inode)->nextscan)
#define NFS_CACHEINV(inode) \
do { \
	NFS_READTIME(inode) = jiffies - NFS_MAXATTRTIMEO(inode) - 1; \
} while (0)
#define NFS_ATTRTIMEO(inode)		(NFS_I(inode)->attrtimeo)
#define NFS_MINATTRTIMEO(inode) \
	(S_ISDIR(inode->i_mode)? NFS_SERVER(inode)->acdirmin \
			       : NFS_SERVER(inode)->acregmin)
#define NFS_MAXATTRTIMEO(inode) \
	(S_ISDIR(inode->i_mode)? NFS_SERVER(inode)->acdirmax \
			       : NFS_SERVER(inode)->acregmax)
#define NFS_ATTRTIMEO_UPDATE(inode)	(NFS_I(inode)->attrtimeo_timestamp)

#define NFS_FLAGS(inode)		(NFS_I(inode)->flags)
#define NFS_REVALIDATING(inode)		(NFS_FLAGS(inode) & NFS_INO_REVALIDATING)
#define NFS_STALE(inode)		(NFS_FLAGS(inode) & NFS_INO_STALE)

#define NFS_FILEID(inode)		(NFS_I(inode)->fileid)

/* Inode Flags */
#define NFS_USE_READDIRPLUS(inode)	((NFS_FLAGS(inode) & NFS_INO_ADVISE_RDPLUS) ? 1 : 0)

static inline
loff_t page_offset(struct page *page)
{
	return ((loff_t)page->index) << PAGE_CACHE_SHIFT;
}

static inline
unsigned long page_index(struct page *page)
{
	return page->index;
}

/*
 * linux/fs/nfs/inode.c
 */
extern void nfs_zap_caches(struct inode *);
extern int nfs_inode_is_stale(struct inode *, struct nfs_fh *,
				struct nfs_fattr *);
extern struct inode *nfs_fhget(struct dentry *, struct nfs_fh *,
				struct nfs_fattr *);
extern int __nfs_refresh_inode(struct inode *, struct nfs_fattr *);
extern int nfs_getattr(struct vfsmount *, struct dentry *, struct kstat *);
extern int nfs_permission(struct inode *, int);
extern int nfs_open(struct inode *, struct file *);
extern int nfs_release(struct inode *, struct file *);
extern int __nfs_revalidate_inode(struct nfs_server *, struct inode *);
extern int nfs_setattr(struct dentry *, struct iattr *);

/*
 * linux/fs/nfs/file.c
 */
extern struct inode_operations nfs_file_inode_operations;
extern struct file_operations nfs_file_operations;
extern struct address_space_operations nfs_file_aops;

static __inline__ struct rpc_cred *
nfs_file_cred(struct file *file)
{
	struct rpc_cred *cred = NULL;
	if (file)
		cred = (struct rpc_cred *)file->private_data;
#ifdef RPC_DEBUG
	if (cred && cred->cr_magic != RPCAUTH_CRED_MAGIC)
		BUG();
#endif
	return cred;
}

/*
 * linux/fs/nfs/dir.c
 */
extern struct inode_operations nfs_dir_inode_operations;
extern struct file_operations nfs_dir_operations;
extern struct dentry_operations nfs_dentry_operations;

/*
 * linux/fs/nfs/symlink.c
 */
extern struct inode_operations nfs_symlink_inode_operations;

/*
 * linux/fs/nfs/locks.c
 */
extern int nfs_lock(struct file *, int, struct file_lock *);

/*
 * linux/fs/nfs/unlink.c
 */
extern int  nfs_async_unlink(struct dentry *);
extern void nfs_complete_unlink(struct dentry *);

/*
 * linux/fs/nfs/write.c
 */
extern int  nfs_writepage(struct page *);
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_file(struct inode *, struct file *, unsigned long, unsigned int, int);
extern int  nfs_flush_file(struct inode *, struct file *, unsigned long, unsigned int, int);
extern int  nfs_flush_list(struct list_head *, int, int);
extern int  nfs_scan_lru_dirty(struct nfs_server *, struct list_head *);
extern int  nfs_scan_lru_dirty_timeout(struct nfs_server *, struct list_head *);
#ifdef CONFIG_NFS_V3
extern int  nfs_commit_file(struct inode *, struct file *, unsigned long, unsigned int, int);
extern int  nfs_commit_list(struct list_head *, int);
extern int  nfs_scan_lru_commit(struct nfs_server *, struct list_head *);
extern int  nfs_scan_lru_commit_timeout(struct nfs_server *, struct list_head *);
#endif

static inline int
nfs_have_read(struct inode *inode)
{
	return !list_empty(&NFS_I(inode)->read);
}

static inline int
nfs_have_writebacks(struct inode *inode)
{
	return !list_empty(&NFS_I(inode)->writeback);
}

static inline int
nfs_wb_all(struct inode *inode)
{
	int error = nfs_sync_file(inode, 0, 0, 0, FLUSH_WAIT);
	return (error < 0) ? error : 0;
}

/*
 * Write back all requests on one page - we do this before reading it.
 */
static inline int
nfs_wb_page(struct inode *inode, struct page* page)
{
	int error = nfs_sync_file(inode, 0, page_index(page), 1, FLUSH_WAIT | FLUSH_STABLE);
	return (error < 0) ? error : 0;
}

/*
 * Write back all pending writes for one user.. 
 */
static inline int
nfs_wb_file(struct inode *inode, struct file *file)
{
	int error = nfs_sync_file(inode, file, 0, 0, FLUSH_WAIT);
	return (error < 0) ? error : 0;
}

/*
 * linux/fs/nfs/read.c
 */
extern int  nfs_readpage(struct file *, struct page *);
extern int  nfs_pagein_inode(struct inode *, unsigned long, unsigned int);
extern int  nfs_pagein_list(struct list_head *, int);
extern int  nfs_scan_lru_read(struct nfs_server *, struct list_head *);
extern int  nfs_scan_lru_read_timeout(struct nfs_server *, struct list_head *);

/*
 * linux/fs/mount_clnt.c
 * (Used only by nfsroot module)
 */
extern int  nfs_mount(struct sockaddr_in *, char *, struct nfs_fh *);
extern int  nfs3_mount(struct sockaddr_in *, char *, struct nfs_fh *);

/*
 * inline functions
 */
static inline int
nfs_revalidate_inode(struct nfs_server *server, struct inode *inode)
{
	if (time_before(jiffies, NFS_READTIME(inode)+NFS_ATTRTIMEO(inode)))
		return NFS_STALE(inode) ? -ESTALE : 0;
	return __nfs_revalidate_inode(server, inode);
}

static inline int
nfs_refresh_inode(struct inode *inode, struct nfs_fattr *fattr)
{
	if ((fattr->valid & NFS_ATTR_FATTR) == 0)
		return 0;
	return __nfs_refresh_inode(inode,fattr);
}

static inline loff_t
nfs_size_to_loff_t(__u64 size)
{
	loff_t maxsz = (((loff_t) ULONG_MAX) << PAGE_CACHE_SHIFT) + PAGE_CACHE_SIZE - 1;
	if (size > maxsz)
		return maxsz;
	return (loff_t) size;
}

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;
}

static inline time_t
nfs_time_to_secs(__u64 time)
{
	return (time_t)(time >> 32);
}

/* NFS root */

extern void * nfs_root_data(void);

#define nfs_wait_event(clnt, wq, condition)				\
({									\
	int __retval = 0;						\
	if (clnt->cl_intr) {						\
		sigset_t oldmask;					\
		rpc_clnt_sigmask(clnt, &oldmask);			\
		__retval = wait_event_interruptible(wq, condition);	\
		rpc_clnt_sigunmask(clnt, &oldmask);			\
	} else								\
		wait_event(wq, condition);				\
	__retval;							\
})

#ifdef CONFIG_NFS_V3

#define NFS_JUKEBOX_RETRY_TIME (5 * HZ)
static inline int
nfs_async_handle_jukebox(struct rpc_task *task)
{
	if (task->tk_status != -EJUKEBOX)
		return 0;
	task->tk_status = 0;
	rpc_restart_call(task);
	rpc_delay(task, NFS_JUKEBOX_RETRY_TIME);
	return 1;
}

#else

static inline int
nfs_async_handle_jukebox(struct rpc_task *task)
{
	return 0;
}
#endif /* CONFIG_NFS_V3 */

#endif /* __KERNEL__ */

/*
 * NFS debug flags
 */
#define NFSDBG_VFS		0x0001
#define NFSDBG_DIRCACHE		0x0002
#define NFSDBG_LOOKUPCACHE	0x0004
#define NFSDBG_PAGECACHE	0x0008
#define NFSDBG_PROC		0x0010
#define NFSDBG_XDR		0x0020
#define NFSDBG_FILE		0x0040
#define NFSDBG_ROOT		0x0080
#define NFSDBG_ALL		0xFFFF

#ifdef __KERNEL__
# undef ifdebug
# ifdef NFS_DEBUG
#  define ifdebug(fac)		if (nfs_debug & NFSDBG_##fac)
# else
#  define ifdebug(fac)		if (0)
# endif
#endif /* __KERNEL */

#endif