1/*
2 * Copyright (C) Sistina Software, Inc.  1997-2003 All rights reserved.
3 * Copyright (C) 2004-2006 Red Hat, Inc.  All rights reserved.
4 *
5 * This copyrighted material is made available to anyone wishing to use,
6 * modify, copy, or redistribute it subject to the terms and conditions
7 * of the GNU General Public License version 2.
8 */
9
10#include <linux/slab.h>
11#include <linux/spinlock.h>
12#include <linux/completion.h>
13#include <linux/buffer_head.h>
14#include <linux/mm.h>
15#include <linux/pagemap.h>
16#include <linux/gfs2_ondisk.h>
17#include <linux/lm_interface.h>
18
19#include "gfs2.h"
20#include "incore.h"
21#include "bmap.h"
22#include "glock.h"
23#include "inode.h"
24#include "ops_vm.h"
25#include "quota.h"
26#include "rgrp.h"
27#include "trans.h"
28#include "util.h"
29
30static struct page *gfs2_private_nopage(struct vm_area_struct *area,
31					unsigned long address, int *type)
32{
33	struct gfs2_inode *ip = GFS2_I(area->vm_file->f_mapping->host);
34
35	set_bit(GIF_PAGED, &ip->i_flags);
36	return filemap_nopage(area, address, type);
37}
38
39static int alloc_page_backing(struct gfs2_inode *ip, struct page *page)
40{
41	struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
42	unsigned long index = page->index;
43	u64 lblock = index << (PAGE_CACHE_SHIFT -
44				    sdp->sd_sb.sb_bsize_shift);
45	unsigned int blocks = PAGE_CACHE_SIZE >> sdp->sd_sb.sb_bsize_shift;
46	struct gfs2_alloc *al;
47	unsigned int data_blocks, ind_blocks;
48	unsigned int x;
49	int error;
50
51	al = gfs2_alloc_get(ip);
52
53	error = gfs2_quota_lock(ip, NO_QUOTA_CHANGE, NO_QUOTA_CHANGE);
54	if (error)
55		goto out;
56
57	error = gfs2_quota_check(ip, ip->i_inode.i_uid, ip->i_inode.i_gid);
58	if (error)
59		goto out_gunlock_q;
60
61	gfs2_write_calc_reserv(ip, PAGE_CACHE_SIZE, &data_blocks, &ind_blocks);
62
63	al->al_requested = data_blocks + ind_blocks;
64
65	error = gfs2_inplace_reserve(ip);
66	if (error)
67		goto out_gunlock_q;
68
69	error = gfs2_trans_begin(sdp, al->al_rgd->rd_ri.ri_length +
70				 ind_blocks + RES_DINODE +
71				 RES_STATFS + RES_QUOTA, 0);
72	if (error)
73		goto out_ipres;
74
75	if (gfs2_is_stuffed(ip)) {
76		error = gfs2_unstuff_dinode(ip, NULL);
77		if (error)
78			goto out_trans;
79	}
80
81	for (x = 0; x < blocks; ) {
82		u64 dblock;
83		unsigned int extlen;
84		int new = 1;
85
86		error = gfs2_extent_map(&ip->i_inode, lblock, &new, &dblock, &extlen);
87		if (error)
88			goto out_trans;
89
90		lblock += extlen;
91		x += extlen;
92	}
93
94	gfs2_assert_warn(sdp, al->al_alloced);
95
96out_trans:
97	gfs2_trans_end(sdp);
98out_ipres:
99	gfs2_inplace_release(ip);
100out_gunlock_q:
101	gfs2_quota_unlock(ip);
102out:
103	gfs2_alloc_put(ip);
104	return error;
105}
106
107static struct page *gfs2_sharewrite_nopage(struct vm_area_struct *area,
108					   unsigned long address, int *type)
109{
110	struct file *file = area->vm_file;
111	struct gfs2_file *gf = file->private_data;
112	struct gfs2_inode *ip = GFS2_I(file->f_mapping->host);
113	struct gfs2_holder i_gh;
114	struct page *result = NULL;
115	unsigned long index = ((address - area->vm_start) >> PAGE_CACHE_SHIFT) +
116			      area->vm_pgoff;
117	int alloc_required;
118	int error;
119
120	error = gfs2_glock_nq_init(ip->i_gl, LM_ST_EXCLUSIVE, 0, &i_gh);
121	if (error)
122		return NULL;
123
124	set_bit(GIF_PAGED, &ip->i_flags);
125	set_bit(GIF_SW_PAGED, &ip->i_flags);
126
127	error = gfs2_write_alloc_required(ip, (u64)index << PAGE_CACHE_SHIFT,
128					  PAGE_CACHE_SIZE, &alloc_required);
129	if (error)
130		goto out;
131
132	set_bit(GFF_EXLOCK, &gf->f_flags);
133	result = filemap_nopage(area, address, type);
134	clear_bit(GFF_EXLOCK, &gf->f_flags);
135	if (!result || result == NOPAGE_OOM)
136		goto out;
137
138	if (alloc_required) {
139		error = alloc_page_backing(ip, result);
140		if (error) {
141			page_cache_release(result);
142			result = NULL;
143			goto out;
144		}
145		set_page_dirty(result);
146	}
147
148out:
149	gfs2_glock_dq_uninit(&i_gh);
150
151	return result;
152}
153
154struct vm_operations_struct gfs2_vm_ops_private = {
155	.nopage = gfs2_private_nopage,
156};
157
158struct vm_operations_struct gfs2_vm_ops_sharewrite = {
159	.nopage = gfs2_sharewrite_nopage,
160};
161