fs/hpfs/file.c

   1 /*
   2  *  linux/fs/hpfs/file.c
   3  *
   4  *  Mikulas Patocka (mikulas@artax.karlin.mff.cuni.cz), 1998-1999
   5  *
   6  *  file VFS functions
   7  */
   8
   9 #include "hpfs_fn.h"
  10 #include <linux/mpage.h>
  11
  12 #define BLOCKS(size) (((size) + 511) >> 9)
  13
  14 static int hpfs_file_release(struct inode *inode, struct file *file)
  15 {
  16         hpfs_lock(inode->i_sb);
  17         hpfs_write_if_changed(inode);
  18         hpfs_unlock(inode->i_sb);
  19         return 0;
  20 }
  21
  22 int hpfs_file_fsync(struct file *file, loff_t start, loff_t end, int datasync)
  23 {
  24         struct inode *inode = file->f_mapping->host;
  25         int ret;
  26
  27         ret = filemap_write_and_wait_range(file->f_mapping, start, end);
  28         if (ret)
  29                 return ret;
  30         return sync_blockdev(inode->i_sb->s_bdev);
  31 }
  32
  33 /*
  34  * generic_file_read often calls bmap with non-existing sector,
  35  * so we must ignore such errors.
  36  */
  37
  38 static secno hpfs_bmap(struct inode *inode, unsigned file_secno, unsigned *n_secs)
  39 {
  40         struct hpfs_inode_info *hpfs_inode = hpfs_i(inode);
  41         unsigned n, disk_secno;
  42         struct fnode *fnode;
  43         struct buffer_head *bh;
  44         if (BLOCKS(hpfs_i(inode)->mmu_private) <= file_secno) return 0;
  45         n = file_secno - hpfs_inode->i_file_sec;
  46         if (n < hpfs_inode->i_n_secs) {
  47                 *n_secs = hpfs_inode->i_n_secs - n;
  48                 return hpfs_inode->i_disk_sec + n;
  49         }
  50         if (!(fnode = hpfs_map_fnode(inode->i_sb, inode->i_ino, &bh))) return 0;
  51         disk_secno = hpfs_bplus_lookup(inode->i_sb, inode, &fnode->btree, file_secno, bh);
  52         if (disk_secno == -1) return 0;
  53         if (hpfs_chk_sectors(inode->i_sb, disk_secno, 1, "bmap")) return 0;
  54         n = file_secno - hpfs_inode->i_file_sec;
  55         if (n < hpfs_inode->i_n_secs) {
  56                 *n_secs = hpfs_inode->i_n_secs - n;
  57                 return hpfs_inode->i_disk_sec + n;
  58         }
  59         *n_secs = 1;
  60         return disk_secno;
  61 }
  62
  63 void hpfs_truncate(struct inode *i)
  64 {
  65         if (IS_IMMUTABLE(i)) return /*-EPERM*/;
  66         hpfs_lock_assert(i->i_sb);
  67
  68         hpfs_i(i)->i_n_secs = 0;
  69         i->i_blocks = 1 + ((i->i_size + 511) >> 9);
  70         hpfs_i(i)->mmu_private = i->i_size;
  71         hpfs_truncate_btree(i->i_sb, i->i_ino, 1, ((i->i_size + 511) >> 9));
  72         hpfs_write_inode(i);
  73         hpfs_i(i)->i_n_secs = 0;
  74 }
  75
  76 static int hpfs_get_block(struct inode *inode, sector_t iblock, struct buffer_head *bh_result, int create)
  77 {
  78         int r;
  79         secno s;
  80         unsigned n_secs;
  81         hpfs_lock(inode->i_sb);
  82         s = hpfs_bmap(inode, iblock, &n_secs);
  83         if (s) {
  84                 if (bh_result->b_size >> 9 < n_secs)
  85                         n_secs = bh_result->b_size >> 9;
  86                 map_bh(bh_result, inode->i_sb, s);
  87                 bh_result->b_size = n_secs << 9;
  88                 goto ret_0;
  89         }
  90         if (!create) goto ret_0;
  91         if (iblock<<9 != hpfs_i(inode)->mmu_private) {
  92                 BUG();
  93                 r = -EIO;
  94                 goto ret_r;
  95         }
  96         if ((s = hpfs_add_sector_to_btree(inode->i_sb, inode->i_ino, 1, inode->i_blocks - 1)) == -1) {
  97                 hpfs_truncate_btree(inode->i_sb, inode->i_ino, 1, inode->i_blocks - 1);
  98                 r = -ENOSPC;
  99                 goto ret_r;
 100         }
 101         inode->i_blocks++;
 102         hpfs_i(inode)->mmu_private += 512;
 103         set_buffer_new(bh_result);
 104         map_bh(bh_result, inode->i_sb, s);
 105         ret_0:
 106         r = 0;
 107         ret_r:
 108         hpfs_unlock(inode->i_sb);
 109         return r;
 110 }
 111
 112 static int hpfs_readpage(struct file *file, struct page *page)
 113 {
 114         return mpage_readpage(page, hpfs_get_block);
 115 }
 116
 117 static int hpfs_writepage(struct page *page, struct writeback_control *wbc)
 118 {
 119         return block_write_full_page(page, hpfs_get_block, wbc);
 120 }
 121
 122 static int hpfs_readpages(struct file *file, struct address_space *mapping,
 123                           struct list_head *pages, unsigned nr_pages)
 124 {
 125         return mpage_readpages(mapping, pages, nr_pages, hpfs_get_block);
 126 }
 127
 128 static int hpfs_writepages(struct address_space *mapping,
 129                            struct writeback_control *wbc)
 130 {
 131         return mpage_writepages(mapping, wbc, hpfs_get_block);
 132 }
 133
 134 static void hpfs_write_failed(struct address_space *mapping, loff_t to)
 135 {
 136         struct inode *inode = mapping->host;
 137
 138         hpfs_lock(inode->i_sb);
 139
 140         if (to > inode->i_size) {
 141                 truncate_pagecache(inode, inode->i_size);
 142                 hpfs_truncate(inode);
 143         }
 144
 145         hpfs_unlock(inode->i_sb);
 146 }
 147
 148 static int hpfs_write_begin(struct file *file, struct address_space *mapping,
 149                         loff_t pos, unsigned len, unsigned flags,
 150                         struct page **pagep, void **fsdata)
 151 {
 152         int ret;
 153
 154         *pagep = NULL;
 155         ret = cont_write_begin(file, mapping, pos, len, flags, pagep, fsdata,
 156                                 hpfs_get_block,
 157                                 &hpfs_i(mapping->host)->mmu_private);
 158         if (unlikely(ret))
 159                 hpfs_write_failed(mapping, pos + len);
 160
 161         return ret;
 162 }
 163
 164 static int hpfs_write_end(struct file *file, struct address_space *mapping,
 165                         loff_t pos, unsigned len, unsigned copied,
 166                         struct page *pagep, void *fsdata)
 167 {
 168         struct inode *inode = mapping->host;
 169         int err;
 170         err = generic_write_end(file, mapping, pos, len, copied, pagep, fsdata);
 171         if (err < len)
 172                 hpfs_write_failed(mapping, pos + len);
 173         if (!(err < 0)) {
 174                 /* make sure we write it on close, if not earlier */
 175                 hpfs_lock(inode->i_sb);
 176                 hpfs_i(inode)->i_dirty = 1;
 177                 hpfs_unlock(inode->i_sb);
 178         }
 179         return err;
 180 }
 181
 182 static sector_t _hpfs_bmap(struct address_space *mapping, sector_t block)
 183 {
 184         return generic_block_bmap(mapping,block,hpfs_get_block);
 185 }
 186
 187 const struct address_space_operations hpfs_aops = {
 188         .readpage = hpfs_readpage,
 189         .writepage = hpfs_writepage,
 190         .readpages = hpfs_readpages,
 191         .writepages = hpfs_writepages,
 192         .write_begin = hpfs_write_begin,
 193         .write_end = hpfs_write_end,
 194         .bmap = _hpfs_bmap
 195 };
 196
 197 const struct file_operations hpfs_file_ops =
 198 {
 199         .llseek         = generic_file_llseek,
 200         .read_iter      = generic_file_read_iter,
 201         .write_iter     = generic_file_write_iter,
 202         .mmap           = generic_file_mmap,
 203         .release        = hpfs_file_release,
 204         .fsync          = hpfs_file_fsync,
 205         .splice_read    = generic_file_splice_read,
 206 };
 207
 208 const struct inode_operations hpfs_file_iops =
 209 {
 210         .setattr        = hpfs_setattr,
 211 };