/* -*- mode: c; c-basic-offset: 8; indent-tabs-mode: nil; -*-
 * vim:expandtab:shiftwidth=8:tabstop=8:
 *
 *  lustre/smfs/inode.c
 *  Lustre filesystem abstraction routines
 *
 *  Copyright (C) 2004 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.
 */

#define DEBUG_SUBSYSTEM S_SM

#include <linux/kmod.h>
#include <linux/init.h>
#include <linux/fs.h>
#include <linux/slab.h>
#include <linux/string.h>
#include <linux/obd_class.h>
#include <linux/obd_support.h>
#include <linux/lustre_lib.h>
#include <linux/lustre_idl.h>
#include <linux/lustre_fsfilt.h>
#include <linux/lustre_smfs.h>
#include "smfs_internal.h"

static void smfs_init_inode_info(struct inode *inode, void *opaque)
{
        
        struct inode *cache_inode = NULL;
        struct smfs_iget_args *sargs = opaque;
        
        LASSERTF((!I2SMI(inode)), "Inode %lu already has smfs_inode_info %p \n",
                 inode->i_ino, I2SMI(inode));
        
        /* getting backing fs inode. */
        LASSERT(sargs);
        
        cache_inode = igrab(sargs->s_inode); 
        LASSERT(cache_inode);
        
        OBD_ALLOC(inode->u.generic_ip, sizeof(struct smfs_inode_info));

        LASSERT(inode->u.generic_ip);
              
        I2CI(inode) = cache_inode;
        CDEBUG(D_INODE,"Init inode #%lu (%p) icount %u, i_nlink %u\n",
                        inode->i_ino, inode, 
                        atomic_read(&cache_inode->i_count),
                        cache_inode->i_nlink);
        
        post_smfs_inode(inode, cache_inode);
        inode->i_nlink = cache_inode->i_nlink;
        sm_set_inode_ops(inode);

        //inherit parent inode flags
        if (sargs->s_info) { 
                I2SMI(inode)->smi_flags = sargs->s_info->smi_flags;
                CDEBUG(D_INODE, "set inode %lu flags 0x%.8x\n", inode->i_ino,
                      I2SMI(inode)->smi_flags);
        } 
}

static void smfs_clear_inode_info(struct inode *inode)
{
        struct inode *cache_inode = I2CI(inode);
        struct smfs_inode_info * info = I2SMI(inode);
        
        CDEBUG(D_INODE, "Clear_info: inode %lu (%p)\n", inode->i_ino, inode);

        inode->u.generic_ip = NULL;      
        iput(cache_inode);
        OBD_FREE(info, sizeof(*info));
}

#if (LINUX_VERSION_CODE < KERNEL_VERSION(2,5,0))
static void smfs_read_inode2(struct inode *inode, void *opaque)
{
        ENTRY;

        if (!inode) {
                EXIT;
                return;
        }
        
        smfs_init_inode_info(inode, opaque);
        CDEBUG(D_INODE, "read_inode ino %lu icount %d \n",
               inode->i_ino, atomic_read(&inode->i_count));
        EXIT;
}

static int smfs_test_inode(struct inode *inode, unsigned long ino, 
                           void *opaque)
#else
static int smfs_test_inode(struct inode *inode, void *opaque)
#endif
{
        struct smfs_iget_args *sargs = (struct smfs_iget_args*)opaque;

        if (!sargs || (inode->i_ino != sargs->s_inode->i_ino))
                return 0;
        
#ifdef CONFIG_SNAPFS
        if (SMFS_DO_COW(S2SMI(inode->i_sb)) && 
            !smfs_snap_test_inode(inode, opaque))
                return 0;  
#endif
                
        return 1;
}

#if (LINUX_VERSION_CODE >= KERNEL_VERSION(2,5,0))
int smfs_set_inode(struct inode *inode, void *opaque)
{
        struct smfs_iget_args *sargs = opaque;
        
        inode->i_ino = sargs->s_inode->i_ino;
        
        return 0;
}

static struct inode *smfs_iget(struct super_block *sb, ino_t hash,
                        struct smfs_iget_args *sargs)
{
        struct inode *inode;
        LASSERT(hash != 0);

        inode = iget5_locked(sb, hash, smfs_test_inode,
                             smfs_set_inode, sargs);
        if (inode) {
                if (inode->i_state & I_NEW) {
                        smfs_init_inode_info(inode, (void*)sargs);
                        unlock_new_inode(inode);
                }
                
                CDEBUG(D_INODE, "inode: %lu/%u(%p) index %d\n",
                                inode->i_ino, inode->i_generation,
                                inode, sargs->s_index);
                
        }
        return inode;
}
#else
struct inode *smfs_iget(struct super_block *sb, ino_t hash,
                        struct smfs_iget_args *sargs)
{
        struct inode *inode;
        LASSERT(hash != 0);

        inode = iget4(sb, hash, smfs_test_inode, sargs);
        if (inode) {
                struct inode *cache_inode = I2CI(inode);
                
                CDEBUG(D_INODE, "new inode: %lu/%u(%p)\n", inode->i_ino,
                       inode->i_generation, inode);
        }
        return inode;
}
#endif

struct inode *smfs_get_inode(struct super_block *sb, struct inode * cache_inode,
                             struct smfs_inode_info * dir_info, int index)
{
        struct smfs_iget_args sargs;
        struct inode *inode;
        ENTRY;
       
        sargs.s_inode = cache_inode; 
        sargs.s_info = dir_info; 
        sargs.s_index = index;
        
        inode = smfs_iget(sb, cache_inode->i_ino, &sargs);
        LASSERT(inode);
        RETURN(inode);
}
#ifdef FC3_KERNEL 
static int smfs_write_inode(struct inode *inode, int wait)
#else
static void smfs_write_inode(struct inode *inode, int wait)
#endif
{
        struct inode *cache_inode = I2CI(inode);
#ifdef FC3_KERNEL
        int rc = 0;
#endif        
        ENTRY;

        LASSERT(cache_inode);
        
        CDEBUG(D_INODE,"Write inode %lu\n",inode->i_ino);

        pre_smfs_inode(inode, cache_inode);
        
#ifdef FC3_KERNEL
        rc = cache_inode->i_sb->s_op->write_inode(cache_inode, wait);
#else
        cache_inode->i_sb->s_op->write_inode(cache_inode, wait);
#endif
        post_smfs_inode(inode, cache_inode);
        
#ifdef FC3_KERNEL
        RETURN(rc);
#else
        EXIT;
#endif
}

static void smfs_dirty_inode(struct inode *inode)
{
        struct inode *cache_inode;
        ENTRY;

        cache_inode = I2CI(inode);
        LASSERT(cache_inode);
        
        pre_smfs_inode(inode, cache_inode);
    
        S2CSB(inode->i_sb)->s_op->dirty_inode(cache_inode);

        post_smfs_inode(inode, cache_inode);
        EXIT;
}

static void smfs_delete_inode(struct inode *inode)
{
        //struct inode * cache_inode = I2CI(inode);

        //smfs_clear_inode_info(inode);
        clear_inode(inode);
}

static void smfs_clear_inode(struct inode *inode)
{
        smfs_clear_inode_info(inode);
}

static void smfs_write_super(struct super_block *sb)
{
        ENTRY;

        LASSERT(S2CSB(sb));

        S2CSB(sb)->s_op->write_super(S2CSB(sb));
        duplicate_sb(sb, S2CSB(sb));
        EXIT;
}

static void smfs_write_super_lockfs(struct super_block *sb)
{
	struct super_block * cache_sb = S2CSB(sb);
        ENTRY;

        LASSERT(cache_sb);

        cache_sb->s_op->write_super_lockfs(cache_sb);
        duplicate_sb(sb, cache_sb);
        EXIT;
}

static void smfs_unlockfs(struct super_block *sb)
{
	struct super_block * cache_sb = S2CSB(sb);
        ENTRY;

        LASSERT(cache_sb);
        
        cache_sb->s_op->unlockfs(cache_sb);

        duplicate_sb(sb, cache_sb);
        EXIT;
}

#if (LINUX_VERSION_CODE < KERNEL_VERSION(2,5,0))
static int smfs_statfs(struct super_block *sb, struct statfs *buf)
#else
static int smfs_statfs(struct super_block *sb, struct kstatfs *buf)
#endif
{
        struct super_block *cache_sb = S2CSB(sb);
        int rc = 0;
        ENTRY;

        LASSERT(cache_sb);

        rc = cache_sb->s_op->statfs(cache_sb, buf);
        duplicate_sb(sb, cache_sb);

        RETURN(rc);
}

static int smfs_remount(struct super_block *sb, int *flags, char *data)
{
        struct super_block *cache_sb = S2CSB(sb);
        int rc = 0;
        ENTRY;

        LASSERT(cache_sb);

        rc = cache_sb->s_op->remount_fs(cache_sb, flags, data);
        duplicate_sb(sb, cache_sb);

        RETURN(rc);
}

struct super_operations smfs_super_ops = {
#if (LINUX_VERSION_CODE < KERNEL_VERSION(2,5,0))
        .read_inode2        = smfs_read_inode2,
#endif 
        .clear_inode        = smfs_clear_inode,
        .put_super          = smfs_put_super,
        .delete_inode       = smfs_delete_inode,
        .write_inode        = smfs_write_inode,
        .dirty_inode        = smfs_dirty_inode, /* BKL not held. */
        .write_super        = smfs_write_super, /* BKL held */
        .write_super_lockfs = smfs_write_super_lockfs, /* BKL not held. */
        .unlockfs           = smfs_unlockfs,    /* BKL not held. */
        .statfs             = smfs_statfs,      /* BKL held */
        .remount_fs         = smfs_remount,     /* BKL held */
};