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/*

 * Copyright (C) Sistina Software, Inc.  1997-2003 All rights reserved.

 * Copyright (C) 2004-2006 Red Hat, Inc.  All rights reserved.

 *

 * This copyrighted material is made available to anyone wishing to use,

 * modify, copy, or redistribute it subject to the terms and conditions

 * of the GNU General Public License version 2.

 */

#include <linux/slab.h>

#include <linux/spinlock.h>

#include <linux/completion.h>

#include <linux/buffer_head.h>

#include <linux/mm.h>

#include <linux/pagemap.h>

#include <linux/gfs2_ondisk.h>

#include <linux/lm_interface.h>

#include "gfs2.h"

#include "incore.h"

#include "bmap.h"

#include "glock.h"

#include "inode.h"

#include "ops_vm.h"

#include "quota.h"

#include "rgrp.h"

#include "trans.h"

#include "util.h"

static int gfs2_private_fault(struct vm_area_struct *vma, struct vm_fault *vmf)

{

        struct gfs2_inode *ip = GFS2_I(vma->vm_file->f_mapping->host);

        set_bit(GIF_PAGED, &ip->i_flags);

        return filemap_fault(vma, vmf);

}

static int alloc_page_backing(struct gfs2_inode *ip, struct page *page)

{

        struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);

        unsigned long index = page->index;

        u64 lblock = index << (PAGE_CACHE_SHIFT -

                                    sdp->sd_sb.sb_bsize_shift);

        unsigned int blocks = PAGE_CACHE_SIZE >> sdp->sd_sb.sb_bsize_shift;

        struct gfs2_alloc *al;

        unsigned int data_blocks, ind_blocks;

        unsigned int x;

        int error;

        al = gfs2_alloc_get(ip);

        error = gfs2_quota_lock(ip, NO_QUOTA_CHANGE, NO_QUOTA_CHANGE);

        if (error)

                goto out;

        error = gfs2_quota_check(ip, ip->i_inode.i_uid, ip->i_inode.i_gid);

        if (error)

                goto out_gunlock_q;

        gfs2_write_calc_reserv(ip, PAGE_CACHE_SIZE, &data_blocks, &ind_blocks);

        al->al_requested = data_blocks + ind_blocks;

        error = gfs2_inplace_reserve(ip);

        if (error)

                goto out_gunlock_q;

        error = gfs2_trans_begin(sdp, al->al_rgd->rd_length +

                                 ind_blocks + RES_DINODE +

                                 RES_STATFS + RES_QUOTA, 0);

        if (error)

                goto out_ipres;

        if (gfs2_is_stuffed(ip)) {

                error = gfs2_unstuff_dinode(ip, NULL);

                if (error)

                        goto out_trans;

        }

        for (x = 0; x < blocks; ) {

                u64 dblock;

                unsigned int extlen;

                int new = 1;

                error = gfs2_extent_map(&ip->i_inode, lblock, &new, &dblock, &extlen);

                if (error)

                        goto out_trans;

                lblock += extlen;

                x += extlen;

        }

        gfs2_assert_warn(sdp, al->al_alloced);

out_trans:

        gfs2_trans_end(sdp);

out_ipres:

        gfs2_inplace_release(ip);

out_gunlock_q:

        gfs2_quota_unlock(ip);

out:

        gfs2_alloc_put(ip);

        return error;

}

static int gfs2_sharewrite_fault(struct vm_area_struct *vma,

                                                struct vm_fault *vmf)

{

        struct file *file = vma->vm_file;

        struct gfs2_file *gf = file->private_data;

        struct gfs2_inode *ip = GFS2_I(file->f_mapping->host);

        struct gfs2_holder i_gh;

        int alloc_required;

        int error;

        int ret = 0;

        error = gfs2_glock_nq_init(ip->i_gl, LM_ST_EXCLUSIVE, 0, &i_gh);

        if (error)

                goto out;

        set_bit(GIF_PAGED, &ip->i_flags);

        set_bit(GIF_SW_PAGED, &ip->i_flags);

        error = gfs2_write_alloc_required(ip,

                                        (u64)vmf->pgoff << PAGE_CACHE_SHIFT,

                                        PAGE_CACHE_SIZE, &alloc_required);

        if (error) {

                ret = VM_FAULT_OOM; /* XXX: are these right? */

                goto out_unlock;

        }

        set_bit(GFF_EXLOCK, &gf->f_flags);

        ret = filemap_fault(vma, vmf);

        clear_bit(GFF_EXLOCK, &gf->f_flags);

        if (ret & VM_FAULT_ERROR)

                goto out_unlock;

        if (alloc_required) {

                /* XXX: do we need to drop page lock around alloc_page_backing?*/

                error = alloc_page_backing(ip, vmf->page);

                if (error) {

                        /*

                         * VM_FAULT_LOCKED should always be the case for

                         * filemap_fault, but it may not be in a future

                         * implementation.

                         */

                        if (ret & VM_FAULT_LOCKED)

                                unlock_page(vmf->page);

                        page_cache_release(vmf->page);

                        ret = VM_FAULT_OOM;

                        goto out_unlock;

                }

                set_page_dirty(vmf->page);

        }

out_unlock:

        gfs2_glock_dq_uninit(&i_gh);

out:

        return ret;

}

struct vm_operations_struct gfs2_vm_ops_private = {

        .fault = gfs2_private_fault,

};

struct vm_operations_struct gfs2_vm_ops_sharewrite = {

        .fault = gfs2_sharewrite_fault,

};