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/*
* 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/nfs_fs_sb.h>
#include <linux/sunrpc/auth.h>
#include <linux/nfs_xdr.h>
#include <asm/atomic.h>
/*
* Valid flags for a dirty buffer
*/
#define PG_BUSY 0
#define PG_NEED_COMMIT 1
#define PG_NEED_RESCHED 2
struct nfs_page {
struct list_head wb_list, /* Defines state of page: */
*wb_list_head; /* read/write/commit */
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 */
unsigned long 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 */
atomic_t wb_count; /* reference count */
unsigned long wb_flags;
struct nfs_writeverf wb_verf; /* Commit cookie */
};
#define NFS_WBACK_BUSY(req) (test_bit(PG_BUSY,&(req)->wb_flags))
#define NFS_NEED_COMMIT(req) (test_bit(PG_NEED_COMMIT,&(req)->wb_flags))
#define NFS_NEED_RESCHED(req) (test_bit(PG_NEED_RESCHED,&(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 void nfs_list_add_request(struct nfs_page *, struct list_head *);
extern int nfs_scan_list(struct list_head *, struct list_head *,
unsigned long, unsigned int);
extern int nfs_coalesce_requests(struct list_head *, struct list_head *,
unsigned int);
extern int nfs_wait_on_request(struct nfs_page *);
extern void nfs_unlock_request(struct nfs_page *req);
/*
* Lock the page of an asynchronous request without incrementing the wb_count
*/
static inline int
nfs_lock_request_dontget(struct nfs_page *req)
{
if (test_and_set_bit(PG_BUSY, &req->wb_flags))
return 0;
return 1;
}
/*
* Lock the page of an asynchronous request
*/
static inline int
nfs_lock_request(struct nfs_page *req)
{
if (test_and_set_bit(PG_BUSY, &req->wb_flags))
return 0;
atomic_inc(&req->wb_count);
return 1;
}
/**
* 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;
if (!NFS_WBACK_BUSY(req)) {
printk(KERN_ERR "NFS: unlocked request attempted removed from list!\n");
BUG();
}
list_del_init(&req->wb_list);
req->wb_list_head = NULL;
}
static inline int
nfs_defer_commit(struct nfs_page *req)
{
if (test_and_set_bit(PG_NEED_COMMIT, &req->wb_flags))
return 0;
return 1;
}
static inline void
nfs_clear_commit(struct nfs_page *req)
{
smp_mb__before_clear_bit();
clear_bit(PG_NEED_COMMIT, &req->wb_flags);
smp_mb__after_clear_bit();
}
static inline int
nfs_defer_reschedule(struct nfs_page *req)
{
if (test_and_set_bit(PG_NEED_RESCHED, &req->wb_flags))
return 0;
return 1;
}
static inline void
nfs_clear_reschedule(struct nfs_page *req)
{
smp_mb__before_clear_bit();
clear_bit(PG_NEED_RESCHED, &req->wb_flags);
smp_mb__after_clear_bit();
}
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 */
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