root/include/linux/nfs_page.h

INCLUDED FROM

DEFINITIONS

1. nfs_lock_request_dontget
2. nfs_list_add_request
3. nfs_list_remove_request
4. nfs_list_entry
5. req_offset

/*
 * linux/include/linux/nfs_page.h
 *
 * Copyright (C) 2000 Trond Myklebust
 *
 * NFS page cache wrapper.
 */

#ifndef _LINUX_NFS_PAGE_H
#define _LINUX_NFS_PAGE_H


#include <linux/list.h>
#include <linux/pagemap.h>
#include <linux/wait.h>
#include <linux/sunrpc/auth.h>
#include <linux/nfs_xdr.h>

#include <linux/kref.h>

/*
 * Valid flags for the radix tree
 */
#define NFS_PAGE_TAG_LOCKED     0
#define NFS_PAGE_TAG_COMMIT     1

/*
 * Valid flags for a dirty buffer
 */
enum {
        PG_BUSY = 0,
        PG_CLEAN,
        PG_NEED_COMMIT,
        PG_NEED_RESCHED,
};

struct nfs_inode;
struct nfs_page {
        struct list_head        wb_list;        /* Defines state of page: */
        struct page             *wb_page;       /* page to read in/write out */
        struct nfs_open_context *wb_context;    /* File state context info */
        atomic_t                wb_complete;    /* i/os we're waiting for */
        pgoff_t                 wb_index;       /* Offset >> PAGE_CACHE_SHIFT */
        unsigned int            wb_offset,      /* Offset & ~PAGE_CACHE_MASK */
                                wb_pgbase,      /* Start of page data */
                                wb_bytes;       /* Length of request */
        struct kref             wb_kref;        /* reference count */
        unsigned long           wb_flags;
        struct nfs_writeverf    wb_verf;        /* Commit cookie */
};

struct nfs_pageio_descriptor {
        struct list_head        pg_list;
        unsigned long           pg_bytes_written;
        size_t                  pg_count;
        size_t                  pg_bsize;
        unsigned int            pg_base;

        struct inode            *pg_inode;
        int                     (*pg_doio)(struct inode *, struct list_head *, unsigned int, size_t, int);
        int                     pg_ioflags;
        int                     pg_error;
};

#define NFS_WBACK_BUSY(req)     (test_bit(PG_BUSY,&(req)->wb_flags))

extern  struct nfs_page *nfs_create_request(struct nfs_open_context *ctx,
                                            struct inode *inode,
                                            struct page *page,
                                            unsigned int offset,
                                            unsigned int count);
extern  void nfs_clear_request(struct nfs_page *req);
extern  void nfs_release_request(struct nfs_page *req);


extern  int nfs_scan_list(struct nfs_inode *nfsi, struct list_head *dst,
                          pgoff_t idx_start, unsigned int npages, int tag);
extern  void nfs_pageio_init(struct nfs_pageio_descriptor *desc,
                             struct inode *inode,
                             int (*doio)(struct inode *, struct list_head *, unsigned int, size_t, int),
                             size_t bsize,
                             int how);
extern  int nfs_pageio_add_request(struct nfs_pageio_descriptor *,
                                   struct nfs_page *);
extern  void nfs_pageio_complete(struct nfs_pageio_descriptor *desc);
extern  void nfs_pageio_cond_complete(struct nfs_pageio_descriptor *, pgoff_t);
extern  int nfs_wait_on_request(struct nfs_page *);
extern  void nfs_unlock_request(struct nfs_page *req);
extern  int nfs_set_page_tag_locked(struct nfs_page *req);
extern  void nfs_clear_page_tag_locked(struct nfs_page *req);


/*
 * Lock the page of an asynchronous request without getting a new reference
 */
static inline int
nfs_lock_request_dontget(struct nfs_page *req)
{
        return !test_and_set_bit(PG_BUSY, &req->wb_flags);
}

/**
 * nfs_list_add_request - Insert a request into a list
 * @req: request
 * @head: head of list into which to insert the request.
 */
static inline void
nfs_list_add_request(struct nfs_page *req, struct list_head *head)
{
        list_add_tail(&req->wb_list, head);
}


/**
 * nfs_list_remove_request - Remove a request from its wb_list
 * @req: request
 */
static inline void
nfs_list_remove_request(struct nfs_page *req)
{
        if (list_empty(&req->wb_list))
                return;
        list_del_init(&req->wb_list);
}

static inline struct nfs_page *
nfs_list_entry(struct list_head *head)
{
        return list_entry(head, struct nfs_page, wb_list);
}

static inline
loff_t req_offset(struct nfs_page *req)
{
        return (((loff_t)req->wb_index) << PAGE_CACHE_SHIFT) + req->wb_offset;
}

#endif /* _LINUX_NFS_PAGE_H */