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 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
  30 static int gfs2_private_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
  31 {
  32         struct gfs2_inode *ip = GFS2_I(vma->vm_file->f_mapping->host);
  33
  34         set_bit(GIF_PAGED, &ip->i_flags);
  35         return filemap_fault(vma, vmf);
  36 }
  37
  38 static int alloc_page_backing(struct gfs2_inode *ip, struct page *page)
  39 {
  40         struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
  41         unsigned long index = page->index;
  42         u64 lblock = index << (PAGE_CACHE_SHIFT -
  43                                     sdp->sd_sb.sb_bsize_shift);
  44         unsigned int blocks = PAGE_CACHE_SIZE >> sdp->sd_sb.sb_bsize_shift;
  45         struct gfs2_alloc *al;
  46         unsigned int data_blocks, ind_blocks;
  47         unsigned int x;
  48         int error;
  49
  50         al = gfs2_alloc_get(ip);
  51
  52         error = gfs2_quota_lock(ip, NO_QUOTA_CHANGE, NO_QUOTA_CHANGE);
  53         if (error)
  54                 goto out;
  55
  56         error = gfs2_quota_check(ip, ip->i_inode.i_uid, ip->i_inode.i_gid);
  57         if (error)
  58                 goto out_gunlock_q;
  59
  60         gfs2_write_calc_reserv(ip, PAGE_CACHE_SIZE, &data_blocks, &ind_blocks);
  61
  62         al->al_requested = data_blocks + ind_blocks;
  63
  64         error = gfs2_inplace_reserve(ip);
  65         if (error)
  66                 goto out_gunlock_q;
  67
  68         error = gfs2_trans_begin(sdp, al->al_rgd->rd_length +
  69                                  ind_blocks + RES_DINODE +
  70                                  RES_STATFS + RES_QUOTA, 0);
  71         if (error)
  72                 goto out_ipres;
  73
  74         if (gfs2_is_stuffed(ip)) {
  75                 error = gfs2_unstuff_dinode(ip, NULL);
  76                 if (error)
  77                         goto out_trans;
  78         }
  79
  80         for (x = 0; x < blocks; ) {
  81                 u64 dblock;
  82                 unsigned int extlen;
  83                 int new = 1;
  84
  85                 error = gfs2_extent_map(&ip->i_inode, lblock, &new, &dblock, &extlen);
  86                 if (error)
  87                         goto out_trans;
  88
  89                 lblock += extlen;
  90                 x += extlen;
  91         }
  92
  93         gfs2_assert_warn(sdp, al->al_alloced);
  94
  95 out_trans:
  96         gfs2_trans_end(sdp);
  97 out_ipres:
  98         gfs2_inplace_release(ip);
  99 out_gunlock_q:
 100         gfs2_quota_unlock(ip);
 101 out:
 102         gfs2_alloc_put(ip);
 103         return error;
 104 }
 105
 106 static int gfs2_sharewrite_fault(struct vm_area_struct *vma,
 107                                                 struct vm_fault *vmf)
 108 {
 109         struct file *file = vma->vm_file;
 110         struct gfs2_file *gf = file->private_data;
 111         struct gfs2_inode *ip = GFS2_I(file->f_mapping->host);
 112         struct gfs2_holder i_gh;
 113         int alloc_required;
 114         int error;
 115         int ret = 0;
 116
 117         error = gfs2_glock_nq_init(ip->i_gl, LM_ST_EXCLUSIVE, 0, &i_gh);
 118         if (error)
 119                 goto out;
 120
 121         set_bit(GIF_PAGED, &ip->i_flags);
 122         set_bit(GIF_SW_PAGED, &ip->i_flags);
 123
 124         error = gfs2_write_alloc_required(ip,
 125                                         (u64)vmf->pgoff << PAGE_CACHE_SHIFT,
 126                                         PAGE_CACHE_SIZE, &alloc_required);
 127         if (error) {
 128                 ret = VM_FAULT_OOM; /* XXX: are these right? */
 129                 goto out_unlock;
 130         }
 131
 132         set_bit(GFF_EXLOCK, &gf->f_flags);
 133         ret = filemap_fault(vma, vmf);
 134         clear_bit(GFF_EXLOCK, &gf->f_flags);
 135         if (ret & VM_FAULT_ERROR)
 136                 goto out_unlock;
 137
 138         if (alloc_required) {
 139                 /* XXX: do we need to drop page lock around alloc_page_backing?*/
 140                 error = alloc_page_backing(ip, vmf->page);
 141                 if (error) {
 142                         /*
 143                          * VM_FAULT_LOCKED should always be the case for
 144                          * filemap_fault, but it may not be in a future
 145                          * implementation.
 146                          */
 147                         if (ret & VM_FAULT_LOCKED)
 148                                 unlock_page(vmf->page);
 149                         page_cache_release(vmf->page);
 150                         ret = VM_FAULT_OOM;
 151                         goto out_unlock;
 152                 }
 153                 set_page_dirty(vmf->page);
 154         }
 155
 156 out_unlock:
 157         gfs2_glock_dq_uninit(&i_gh);
 158 out:
 159         return ret;
 160 }
 161
 162 struct vm_operations_struct gfs2_vm_ops_private = {
 163         .fault = gfs2_private_fault,
 164 };
 165
 166 struct vm_operations_struct gfs2_vm_ops_sharewrite = {
 167         .fault = gfs2_sharewrite_fault,
 168 };
 169