/* -*- 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 smfs_iget_args *sargs = (struct smfs_iget_args*)opaque;
        struct inode *cache_inode = NULL;
        
        if (sargs)
                cache_inode = iget(S2CSB(inode->i_sb), sargs->s_ino);
        else 
                cache_inode = iget(S2CSB(inode->i_sb), inode->i_ino); 
                 
        OBD_ALLOC(I2SMI(inode), sizeof(struct smfs_inode_info));
        LASSERT(I2SMI(inode));
        I2CI(inode) = cache_inode;
        CDEBUG(D_INODE, "cache_inode i_count ino %lu i_count %d\n",
               cache_inode->i_ino, atomic_read(&cache_inode->i_count));
        post_smfs_inode(inode, cache_inode);
        sm_set_inode_ops(cache_inode, inode);
        if (sargs) { 
                struct inode *dir = sargs->s_inode; 
                if (dir)
                        I2SMI(inode)->smi_flags = I2SMI(dir)->smi_flags;
        }
}

static void smfs_clear_inode_info(struct inode *inode)
{
        if (I2SMI(inode)) {
                struct inode *cache_inode = I2CI(inode);
                LASSERTF(((atomic_read(&cache_inode->i_count) == 1) || 
                           cache_inode == cache_inode->i_sb->s_root->d_inode),  
                         "inode %p cache inode %p %lu i_count %d != 0 \n", 
                          inode, cache_inode, cache_inode->i_ino, 
                          atomic_read(&cache_inode->i_count));
                if (cache_inode != cache_inode->i_sb->s_root->d_inode)
                        iput(cache_inode);
                OBD_FREE(I2SMI(inode), sizeof(struct smfs_inode_info));
                I2SMI(inode) = NULL;
        }
}

static void smfs_read_inode2(struct inode *inode, void *opaque)
{
        ENTRY;

        if (!inode)
                return;
        
        CDEBUG(D_INODE, "read_inode ino %lu\n", inode->i_ino);
        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;
        return;
}

#if (LINUX_VERSION_CODE < KERNEL_VERSION(2,5,0))
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;

        LASSERT(sargs);
        if (!sargs)
                return 1;

        if (inode->i_ino != sargs->s_ino)
                return 0; 
#ifdef CONFIG_SNAPFS        
        if (SMFS_DO_COW(S2SMI(inode->i_sb)) && 
            !smfs_snap_test_inode(inode, opaque))
                return 0;  
#endif  
        if (I2SMI(inode)) {
                struct inode *cache_inode = I2CI(inode);
        
                LASSERTF(cache_inode->i_ino == inode->i_ino, 
                         "inode ino %lu != cache ino %lu",
                         cache_inode->i_ino, inode->i_ino); 
        }
        if (!I2SMI(inode))
                smfs_init_inode_info(inode, opaque); 
        return 1;
}

#if (LINUX_VERSION_CODE >= KERNEL_VERSION(2,5,0))
int smfs_set_inode(struct inode *inode, void *opaque)
{
        smfs_read_inode2(inode, opaque);
        return 0;
}

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)
                        unlock_new_inode(inode);
                CDEBUG(D_VFSTRACE, "inode: %lu/%u(%p) index %d ino %lu \n", 
                       inode->i_ino, inode->i_generation, inode, sargs->s_index, 
                       sargs->s_ino);
                inode->i_ino = hash;
        }
        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);

                LASSERTF((inode->i_ino == cache_inode->i_ino), 
                         "inode %p ino %lu != cache inode %p ino %lu",
                          inode, inode->i_ino, cache_inode, cache_inode->i_ino); 
                CDEBUG(D_VFSTRACE, "inode: %lu/%u(%p)\n", inode->i_ino,
                       inode->i_generation, inode);
        }
        return inode;
}
#endif
struct inode *smfs_get_inode (struct super_block *sb, ino_t hash,
                              struct inode *dir, int index)
{
        struct inode *inode;
        struct smfs_iget_args sargs; 
        ENTRY;
       
        sargs.s_index = index;
        sargs.s_inode = dir; 
        sargs.s_ino = hash; 
        inode = smfs_iget(sb, hash, &sargs);
        
        RETURN(inode);
}
 
static void smfs_delete_inode(struct inode *inode)
{
        struct inode *cache_inode;

        ENTRY;
        if (I2SMI(inode)) {
                cache_inode = I2CI(inode);
                if (!cache_inode || !S2CSB(inode->i_sb))
                        return;
                post_smfs_inode(inode, cache_inode);
                smfs_clear_inode_info(inode);
        }
        inode->i_state = I_CLEAR;
        return;
}

static void smfs_write_inode(struct inode *inode, int wait)
{
        struct inode *cache_inode;

        ENTRY;
        cache_inode = I2CI(inode);

        if (!cache_inode) {
                CWARN("cache inode null\n");
                return;
        }
        pre_smfs_inode(inode, cache_inode);
        if (S2CSB(inode->i_sb)->s_op->write_inode)
                S2CSB(inode->i_sb)->s_op->write_inode(cache_inode, wait);
        
        post_smfs_inode(inode, cache_inode);
        EXIT;
}

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

        ENTRY;
        cache_inode = I2CI(inode);

        if (!cache_inode || !S2CSB(inode->i_sb))
                return;

        pre_smfs_inode(inode, cache_inode);
        if (S2CSB(inode->i_sb)->s_op->dirty_inode)
                S2CSB(inode->i_sb)->s_op->dirty_inode(cache_inode);

        post_smfs_inode(inode, cache_inode);
        EXIT;
}

static void smfs_put_inode(struct inode *inode)
{
        struct inode *cache_inode;

        ENTRY;
        cache_inode = I2CI(inode);

        if (!cache_inode) {
                CWARN("cache inode null\n");
                return;
        }
        
        if (atomic_read(&cache_inode->i_count) > 1) {
                iput(cache_inode);
        }
        
        if (S2CSB(inode->i_sb)->s_op->put_inode)
                S2CSB(inode->i_sb)->s_op->put_inode(cache_inode);
        
        if (atomic_read(&inode->i_count) == 0 &&
            cache_inode->i_sb->s_root->d_inode != cache_inode)
                smfs_clear_inode_info(inode);
        
        EXIT;
}

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

        if (!S2CSB(sb))
                return;

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

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

        if (!inode) return;
        
        cache_inode = I2CI(inode);

        smfs_clear_inode_info(inode);
        
        EXIT;
        return;
}

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

        cache_sb = S2CSB(sb);
        if (!cache_sb)
                return;

        if (cache_sb->s_op->write_super_lockfs)
                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;
        ENTRY;

        cache_sb = S2CSB(sb);
        if (!cache_sb)
                return;

        if (cache_sb->s_op->unlockfs)
                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;
        int rc = 0;
        ENTRY;

        cache_sb = S2CSB(sb);
        if (!cache_sb)
                RETURN(-EINVAL);

        if (cache_sb->s_op->statfs)
                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;
        int rc = 0;
        ENTRY;

        cache_sb = S2CSB(sb);

        if (!cache_sb)
                RETURN(-EINVAL);

        if (cache_sb->s_op->remount_fs)
                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. */
        .put_inode          = smfs_put_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 */
};

int is_smfs_sb(struct super_block *sb)
{
        return (sb->s_op->put_super == smfs_super_ops.put_super);
}
EXPORT_SYMBOL(is_smfs_sb);