/* -*- mode: c; c-basic-offset: 8; indent-tabs-mode: nil; -*-
 * vim:expandtab:shiftwidth=8:tabstop=8:
 *
 *  Copyright (c) 2003 Cluster File Systems, Inc.
 *
 *   This file is part of Lustre, http://www.lustre.org.
 *
 *   Lustre is free software; you can redistribute it and/or
 *   modify it under the terms of version 2 of the GNU General Public
 *   License as published by the Free Software Foundation.
 *
 *   Lustre is distributed in the hope that it will be useful,
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *   GNU General Public License for more details.
 *
 *   You should have received a copy of the GNU General Public License
 *   along with Lustre; if not, write to the Free Software
 *   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 *
 */

#ifndef _COMPAT25_H
#define _COMPAT25_H

#ifdef __KERNEL__

#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,5,0) && LINUX_VERSION_CODE < KERNEL_VERSION(2,5,69)
#error sorry, lustre requires at least 2.5.69
#endif

#include <linux/portals_compat25.h>

/*
 * groups_info related staff
 */
#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,4)

#define NGROUPS_SMALL           NGROUPS
#define NGROUPS_PER_BLOCK       ((int)(EXEC_PAGESIZE / sizeof(gid_t)))
struct group_info {
        int        ngroups;
        atomic_t   usage;
        gid_t      small_block[NGROUPS_SMALL];
        int        nblocks;
        gid_t     *blocks[0];
};
#define current_ngroups current->ngroups
                                                                           
struct group_info *groups_alloc(int gidsetsize);
void groups_free(struct group_info *ginfo);
int groups_search(struct group_info *ginfo, gid_t grp);

#define get_group_info(group_info)                              \
        do {                                                    \
                atomic_inc(&(group_info)->usage);               \
        } while (0)

#define put_group_info(group_info)                              \
        do {                                                    \
                if (atomic_dec_and_test(&(group_info)->usage))  \
                        groups_free(group_info);                \
        } while (0)

#define groups_sort(gi) do {} while (0)

#define GROUP_AT(gi, i) ((gi)->small_block[(i)])

static inline int cleanup_group_info(void)
{
        /* Get rid of unneeded supplementary groups */
        current->ngroups = 0;
        memset(current->groups, 0, sizeof(current->groups));
        return 0;
}

#else /* >= 2.6.4 */

#define current_ngroups current->group_info->ngroups

void groups_sort(struct group_info *ginfo);
int groups_search(struct group_info *ginfo, gid_t grp);

static inline int cleanup_group_info(void)
{
        struct group_info *ginfo;

        ginfo = groups_alloc(0);
        if (!ginfo)
                return -ENOMEM;

        set_current_groups(ginfo);
        put_group_info(ginfo);

        return 0;
}
#endif /* end of groups_info stuff */


#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,5,0)

/*
 * OBD need working random driver, thus all our
 * initialization routines must be called after device
 * driver initialization
 */
#ifndef MODULE
#undef module_init
#define module_init(a)     late_initcall(a)
#endif

/* XXX our code should be using the 2.6 calls, not the other way around */
#define TryLockPage(page)                TestSetPageLocked(page)
#define filemap_fdatasync(mapping)       filemap_fdatawrite(mapping)
#define Page_Uptodate(page)              PageUptodate(page)

#define KDEVT_INIT(val)                 (val)

#define LTIME_S(time)                   (time.tv_sec)
#define ll_path_lookup                  path_lookup
#define ll_permission(inode,mask,nd)    permission(inode,mask,nd)

#define ll_pgcache_lock(mapping)          spin_lock(&mapping->page_lock)
#define ll_pgcache_unlock(mapping)        spin_unlock(&mapping->page_lock)
#define ll_call_writepage(inode, page)  \
                                (inode)->i_mapping->a_ops->writepage(page, NULL)
#define ll_invalidate_inode_pages(inode) \
                                invalidate_inode_pages((inode)->i_mapping)
#define ll_truncate_complete_page(page) \
                                truncate_complete_page(page->mapping, page)

#define ll_vfs_create(a,b,c,d)              vfs_create(a,b,c,d)

#define ll_dev_t                        dev_t
#define kdev_t                          dev_t
#define to_kdev_t(dev)                  (dev)
#define kdev_t_to_nr(dev)               (dev)
#define val_to_kdev(dev)                (dev)
#define ILOOKUP(sb, ino, test, data)    ilookup5(sb, ino, test, data);

#include <linux/writeback.h>

static inline void lustre_daemonize_helper(void)
{
        LASSERT(current->signal != NULL);
        current->signal->session = 1;
        if (current->group_leader)
                current->group_leader->signal->pgrp = 1;
        else
                CERROR("we aren't group leader\n");
        current->signal->tty = NULL;
}

#define __set_page_ll_data(page, llap) \
        do {       \
                page_cache_get(page); \
                SetPagePrivate(page); \
                page->private = (unsigned long)llap; \
        } while (0)
#define __clear_page_ll_data(page) \
        do {       \
                ClearPagePrivate(page); \
                page_cache_release(page); \
                page->private = 0; \
        } while(0)

#define kiobuf bio

#include <linux/proc_fs.h>

#else /* 2.4.. */

#define ll_vfs_create(a,b,c,d)              vfs_create(a,b,c)
#define ll_permission(inode,mask,nd)        permission(inode,mask)
#define ILOOKUP(sb, ino, test, data)        ilookup4(sb, ino, test, data);
#define DCACHE_DISCONNECTED                 DCACHE_NFSD_DISCONNECTED
#define ll_dev_t                            int

static inline void clear_page_dirty(struct page *page)
{
        if (PageDirty(page))
                ClearPageDirty(page); 
}

/* 2.5 uses hlists for some things, like the d_hash.  we'll treat them
 * as 2.5 and let macros drop back.. */
#ifndef HLIST_HEAD /* until we get a kernel newer than l28 */
#define hlist_entry                     list_entry
#define hlist_head                      list_head
#define hlist_node                      list_head
#define HLIST_HEAD                      LIST_HEAD
#define INIT_HLIST_HEAD                 INIT_LIST_HEAD
#define hlist_del_init                  list_del_init
#define hlist_add_head                  list_add
#define hlist_for_each_safe             list_for_each_safe
#endif
#define KDEVT_INIT(val)                 (val)
#define ext3_xattr_set_handle           ext3_xattr_set
#define extN_xattr_set_handle           extN_xattr_set
#define try_module_get                  __MOD_INC_USE_COUNT
#define module_put                      __MOD_DEC_USE_COUNT
#define LTIME_S(time)                   (time)
#if !defined(CONFIG_RH_2_4_20) && !defined(cpu_online)
#define cpu_online(cpu)                 (cpu_online_map & (1<<cpu))
#endif

static inline int ll_path_lookup(const char *path, unsigned flags,
                                 struct nameidata *nd)
{
        int error = 0;
        if (path_init(path, flags, nd))
                error = path_walk(path, nd);
        return error;
}
#define ll_permission(inode,mask,nd)    permission(inode,mask)
typedef long sector_t;

#define ll_pgcache_lock(mapping)        spin_lock(&pagecache_lock)
#define ll_pgcache_unlock(mapping)      spin_unlock(&pagecache_lock)
#define ll_call_writepage(inode, page)  \
                               (inode)->i_mapping->a_ops->writepage(page)
#define ll_invalidate_inode_pages(inode) invalidate_inode_pages(inode)
#define ll_truncate_complete_page(page) truncate_complete_page(page)

static inline void __d_drop(struct dentry *dentry)
{
	list_del(&dentry->d_hash);
	INIT_LIST_HEAD(&dentry->d_hash);
}

static inline void lustre_daemonize_helper(void)
{
        current->session = 1;
        current->pgrp = 1;
        current->tty = NULL;
}

#ifndef HAVE_COND_RESCHED
static inline void cond_resched(void)
{
        if (unlikely(need_resched())) {
                set_current_state(TASK_RUNNING);
                schedule();
        }
}
#endif

static inline int mapping_mapped(struct address_space *mapping)
{
        return mapping->i_mmap_shared ? 1 : 0;
}

/* to find proc_dir_entry from inode. 2.6 has native one -bzzz */
#ifndef HAVE_PDE
#define PDE(ii)         ((ii)->u.generic_ip)
#endif

#define __set_page_ll_data(page, llap) page->private = (unsigned long)llap
#define __clear_page_ll_data(page) page->private = 0
#define PageWriteback(page) 0
#define end_page_writeback(page)

#ifdef ZAP_PAGE_RANGE_VMA
#define ll_zap_page_range(vma, addr, len)  zap_page_range(vma, addr, len)
#else
#define ll_zap_page_range(vma, addr, len)  zap_page_range(vma->vm_mm, addr, len)
#endif

#endif /* end of 2.4 compat macros */

#ifdef HAVE_PAGE_LIST
static inline int mapping_has_pages(struct address_space *mapping)
{
        int rc = 1;

        ll_pgcache_lock(mapping);
        if (list_empty(&mapping->dirty_pages) &&
            list_empty(&mapping->clean_pages) &&
            list_empty(&mapping->locked_pages)) {
                rc = 0;
        }
        ll_pgcache_unlock(mapping);

        return rc;
}

static inline int clear_page_dirty_for_io(struct page *page)
{
        struct address_space *mapping = page->mapping;

        if (page->mapping && PageDirty(page)) {
                ClearPageDirty(page);
                ll_pgcache_lock(mapping);
                list_del(&page->list);
                list_add(&page->list, &mapping->locked_pages);
                ll_pgcache_unlock(mapping);
                return 1;
        }
        return 0;
}
#else
static inline int mapping_has_pages(struct address_space *mapping)
{
        return mapping->nrpages > 0;
}
#endif

#if (LINUX_VERSION_CODE < KERNEL_VERSION(2,6,7))
#define ll_set_dflags(dentry, flags) do { dentry->d_vfs_flags |= flags; } while(0)
#define ll_vfs_symlink(dir, dentry, path, mode) vfs_symlink(dir, dentry, path)
#else
#define ll_set_dflags(dentry, flags) do { \
                spin_lock(&dentry->d_lock); \
                dentry->d_flags |= flags; \
                spin_unlock(&dentry->d_lock); \
        } while(0)
#define ll_vfs_symlink(dir, dentry, path, mode) vfs_symlink(dir, dentry, path, mode)
#endif

#ifdef HAVE_I_ALLOC_SEM
#define UP_WRITE_I_ALLOC_SEM(i) do { up_write(&(i)->i_alloc_sem); } while (0)
#define DOWN_WRITE_I_ALLOC_SEM(i) do { down_write(&(i)->i_alloc_sem); } while(0)
#define LASSERT_MDS_ORPHAN_WRITE_LOCKED(i) LASSERT(down_read_trylock(&(i)->i_alloc_sem) == 0)

#define UP_READ_I_ALLOC_SEM(i) do { up_read(&(i)->i_alloc_sem); } while (0)
#define DOWN_READ_I_ALLOC_SEM(i) do { down_read(&(i)->i_alloc_sem); } while (0)
#define LASSERT_MDS_ORPHAN_READ_LOCKED(i) LASSERT(down_write_trylock(&(i)->i_alloc_sem) == 0)
#define MDS_PACK_MD_LOCK 1
#else
#define UP_READ_I_ALLOC_SEM(i) do { up(&(i)->i_sem); } while (0)
#define DOWN_READ_I_ALLOC_SEM(i) do { down(&(i)->i_sem); } while (0)
#define LASSERT_MDS_ORPHAN_READ_LOCKED(i) LASSERT(down_trylock(&(i)->i_sem) != 0)

#define UP_WRITE_I_ALLOC_SEM(i) do { up(&(i)->i_sem); } while (0)
#define DOWN_WRITE_I_ALLOC_SEM(i) do { down(&(i)->i_sem); } while (0)
#define LASSERT_MDS_ORPHAN_WRITE_LOCKED(i) LASSERT(down_trylock(&(i)->i_sem) != 0)
#define MDS_PACK_MD_LOCK 0
#endif

#endif /* __KERNEL__ */
#endif /* _COMPAT25_H */