fs/gfs2/ops_vm.c

   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 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 <linux/gfs2_ondisk.h>
  18
  19 #include "gfs2.h"
  20 #include "lm_interface.h"
  21 #include "incore.h"
  22 #include "bmap.h"
  23 #include "glock.h"
  24 #include "inode.h"
  25 #include "ops_vm.h"
  26 #include "page.h"
  27 #include "quota.h"
  28 #include "rgrp.h"
  29 #include "trans.h"
  30 #include "util.h"
  31
  32 static void pfault_be_greedy(struct gfs2_inode *ip)
  33 {
  34         unsigned int time;
  35
  36         spin_lock(&ip->i_spin);
  37         time = ip->i_greedy;
  38         ip->i_last_pfault = jiffies;
  39         spin_unlock(&ip->i_spin);
  40
  41         igrab(&ip->i_inode);
  42         if (gfs2_glock_be_greedy(ip->i_gl, time))
  43                 iput(&ip->i_inode);
  44 }
  45
  46 static struct page *gfs2_private_nopage(struct vm_area_struct *area,
  47                                         unsigned long address, int *type)
  48 {
  49         struct gfs2_inode *ip = GFS2_I(area->vm_file->f_mapping->host);
  50         struct gfs2_holder i_gh;
  51         struct page *result;
  52         int error;
  53
  54         error = gfs2_glock_nq_init(ip->i_gl, LM_ST_SHARED, 0, &i_gh);
  55         if (error)
  56                 return NULL;
  57
  58         set_bit(GIF_PAGED, &ip->i_flags);
  59
  60         result = filemap_nopage(area, address, type);
  61
  62         if (result && result != NOPAGE_OOM)
  63                 pfault_be_greedy(ip);
  64
  65         gfs2_glock_dq_uninit(&i_gh);
  66
  67         return result;
  68 }
  69
  70 static int alloc_page_backing(struct gfs2_inode *ip, struct page *page)
  71 {
  72         struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
  73         unsigned long index = page->index;
  74         uint64_t lblock = index << (PAGE_CACHE_SHIFT -
  75                                     sdp->sd_sb.sb_bsize_shift);
  76         unsigned int blocks = PAGE_CACHE_SIZE >> sdp->sd_sb.sb_bsize_shift;
  77         struct gfs2_alloc *al;
  78         unsigned int data_blocks, ind_blocks;
  79         unsigned int x;
  80         int error;
  81
  82         al = gfs2_alloc_get(ip);
  83
  84         error = gfs2_quota_lock(ip, NO_QUOTA_CHANGE, NO_QUOTA_CHANGE);
  85         if (error)
  86                 goto out;
  87
  88         error = gfs2_quota_check(ip, ip->i_di.di_uid, ip->i_di.di_gid);
  89         if (error)
  90                 goto out_gunlock_q;
  91
  92         gfs2_write_calc_reserv(ip, PAGE_CACHE_SIZE, &data_blocks, &ind_blocks);
  93
  94         al->al_requested = data_blocks + ind_blocks;
  95
  96         error = gfs2_inplace_reserve(ip);
  97         if (error)
  98                 goto out_gunlock_q;
  99
 100         error = gfs2_trans_begin(sdp, 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_extent_map(&ip->i_inode, 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 = GFS2_I(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) +
 149                               area->vm_pgoff;
 150         int alloc_required;
 151         int error;
 152
 153         error = gfs2_glock_nq_init(ip->i_gl, LM_ST_EXCLUSIVE, 0, &i_gh);
 154         if (error)
 155                 return NULL;
 156
 157         set_bit(GIF_PAGED, &ip->i_flags);
 158         set_bit(GIF_SW_PAGED, &ip->i_flags);
 159
 160         error = gfs2_write_alloc_required(ip,
 161                                           (uint64_t)index << PAGE_CACHE_SHIFT,
 162                                           PAGE_CACHE_SIZE, &alloc_required);
 163         if (error)
 164                 goto out;
 165
 166         result = filemap_nopage(area, address, type);
 167         if (!result || result == NOPAGE_OOM)
 168                 goto out;
 169
 170         if (alloc_required) {
 171                 error = alloc_page_backing(ip, result);
 172                 if (error) {
 173                         page_cache_release(result);
 174                         result = NULL;
 175                         goto out;
 176                 }
 177                 set_page_dirty(result);
 178         }
 179
 180         pfault_be_greedy(ip);
 181
 182  out:
 183         gfs2_glock_dq_uninit(&i_gh);
 184
 185         return result;
 186 }
 187
 188 struct vm_operations_struct gfs2_vm_ops_private = {
 189         .nopage = gfs2_private_nopage,
 190 };
 191
 192 struct vm_operations_struct gfs2_vm_ops_sharewrite = {
 193         .nopage = gfs2_sharewrite_nopage,
 194 };
 195