[GFS2] The core of GFS2
[linux-2.6] / fs / gfs2 / ops_vm.c
1 /*
2  * Copyright (C) Sistina Software, Inc.  1997-2003 All rights reserved.
3  * Copyright (C) 2004-2005 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 v.2.
8  */
9
10 #include <linux/sched.h>
11 #include <linux/slab.h>
12 #include <linux/spinlock.h>
13 #include <linux/completion.h>
14 #include <linux/buffer_head.h>
15 #include <linux/mm.h>
16 #include <linux/pagemap.h>
17 #include <asm/semaphore.h>
18
19 #include "gfs2.h"
20 #include "bmap.h"
21 #include "glock.h"
22 #include "inode.h"
23 #include "ops_vm.h"
24 #include "page.h"
25 #include "quota.h"
26 #include "rgrp.h"
27 #include "trans.h"
28
29 static void pfault_be_greedy(struct gfs2_inode *ip)
30 {
31         unsigned int time;
32
33         spin_lock(&ip->i_spin);
34         time = ip->i_greedy;
35         ip->i_last_pfault = jiffies;
36         spin_unlock(&ip->i_spin);
37
38         gfs2_inode_hold(ip);
39         if (gfs2_glock_be_greedy(ip->i_gl, time))
40                 gfs2_inode_put(ip);
41 }
42
43 static struct page *gfs2_private_nopage(struct vm_area_struct *area,
44                                         unsigned long address, int *type)
45 {
46         struct gfs2_inode *ip = get_v2ip(area->vm_file->f_mapping->host);
47         struct gfs2_holder i_gh;
48         struct page *result;
49         int error;
50
51         atomic_inc(&ip->i_sbd->sd_ops_vm);
52
53         error = gfs2_glock_nq_init(ip->i_gl, LM_ST_SHARED, 0, &i_gh);
54         if (error)
55                 return NULL;
56
57         set_bit(GIF_PAGED, &ip->i_flags);
58
59         result = filemap_nopage(area, address, type);
60
61         if (result && result != NOPAGE_OOM)
62                 pfault_be_greedy(ip);
63
64         gfs2_glock_dq_uninit(&i_gh);
65
66         return result;
67 }
68
69 static int alloc_page_backing(struct gfs2_inode *ip, struct page *page)
70 {
71         struct gfs2_sbd *sdp = ip->i_sbd;
72         unsigned long index = page->index;
73         uint64_t lblock = index << (PAGE_CACHE_SHIFT - sdp->sd_sb.sb_bsize_shift);
74         unsigned int blocks = PAGE_CACHE_SIZE >> sdp->sd_sb.sb_bsize_shift;
75         struct gfs2_alloc *al;
76         unsigned int data_blocks, ind_blocks;
77         unsigned int x;
78         int error;
79
80         al = gfs2_alloc_get(ip);
81
82         error = gfs2_quota_lock(ip, NO_QUOTA_CHANGE, NO_QUOTA_CHANGE);
83         if (error)
84                 goto out;
85
86         error = gfs2_quota_check(ip, ip->i_di.di_uid, ip->i_di.di_gid);
87         if (error)
88                 goto out_gunlock_q;
89
90         gfs2_write_calc_reserv(ip, PAGE_CACHE_SIZE,
91                               &data_blocks, &ind_blocks);
92
93         al->al_requested = data_blocks + ind_blocks;
94
95         error = gfs2_inplace_reserve(ip);
96         if (error)
97                 goto out_gunlock_q;
98
99         error = gfs2_trans_begin(sdp,
100                                  al->al_rgd->rd_ri.ri_length +
101                                  ind_blocks + RES_DINODE +
102                                  RES_STATFS + RES_QUOTA, 0);
103         if (error)
104                 goto out_ipres;
105
106         if (gfs2_is_stuffed(ip)) {
107                 error = gfs2_unstuff_dinode(ip, gfs2_unstuffer_page, NULL);
108                 if (error)
109                         goto out_trans;
110         }
111
112         for (x = 0; x < blocks; ) {
113                 uint64_t dblock;
114                 unsigned int extlen;
115                 int new = 1;
116
117                 error = gfs2_block_map(ip, lblock, &new, &dblock, &extlen);
118                 if (error)
119                         goto out_trans;
120
121                 lblock += extlen;
122                 x += extlen;
123         }
124
125         gfs2_assert_warn(sdp, al->al_alloced);
126
127  out_trans:
128         gfs2_trans_end(sdp);
129
130  out_ipres:
131         gfs2_inplace_release(ip);
132
133  out_gunlock_q:
134         gfs2_quota_unlock(ip);
135
136  out:
137         gfs2_alloc_put(ip);
138
139         return error;
140 }
141
142 static struct page *gfs2_sharewrite_nopage(struct vm_area_struct *area,
143                                            unsigned long address, int *type)
144 {
145         struct gfs2_inode *ip = get_v2ip(area->vm_file->f_mapping->host);
146         struct gfs2_holder i_gh;
147         struct page *result = NULL;
148         unsigned long index = ((address - area->vm_start) >> PAGE_CACHE_SHIFT) + area->vm_pgoff;
149         int alloc_required;
150         int error;
151
152         atomic_inc(&ip->i_sbd->sd_ops_vm);
153
154         error = gfs2_glock_nq_init(ip->i_gl, LM_ST_EXCLUSIVE, 0, &i_gh);
155         if (error)
156                 return NULL;
157
158         if (gfs2_is_jdata(ip))
159                 goto out;
160
161         set_bit(GIF_PAGED, &ip->i_flags);
162         set_bit(GIF_SW_PAGED, &ip->i_flags);
163
164         error = gfs2_write_alloc_required(ip,
165                                           (uint64_t)index << PAGE_CACHE_SHIFT,
166                                           PAGE_CACHE_SIZE, &alloc_required);
167         if (error)
168                 goto out;
169
170         result = filemap_nopage(area, address, type);
171         if (!result || result == NOPAGE_OOM)
172                 goto out;
173
174         if (alloc_required) {
175                 error = alloc_page_backing(ip, result);
176                 if (error) {
177                         page_cache_release(result);
178                         result = NULL;
179                         goto out;
180                 }
181                 set_page_dirty(result);
182         }
183
184         pfault_be_greedy(ip);
185
186  out:
187         gfs2_glock_dq_uninit(&i_gh);
188
189         return result;
190 }
191
192 struct vm_operations_struct gfs2_vm_ops_private = {
193         .nopage = gfs2_private_nopage,
194 };
195
196 struct vm_operations_struct gfs2_vm_ops_sharewrite = {
197         .nopage = gfs2_sharewrite_nopage,
198 };
199