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
  11 #define BLOCKS(size) (((size) + 511) >> 9)
  12
  13 static int hpfs_file_release(struct inode *inode, struct file *file)
  14 {
  15         hpfs_lock(inode->i_sb);
  16         hpfs_write_if_changed(inode);
  17         hpfs_unlock(inode->i_sb);
  18         return 0;
  19 }
  20
  21 int hpfs_file_fsync(struct file *file, int datasync)
  22 {
  23         /*return file_fsync(file, datasync);*/
  24         return 0; /* Don't fsync :-) */
  25 }
  26
  27 /*
  28  * generic_file_read often calls bmap with non-existing sector,
  29  * so we must ignore such errors.
  30  */
  31
  32 static secno hpfs_bmap(struct inode *inode, unsigned file_secno)
  33 {
  34         struct hpfs_inode_info *hpfs_inode = hpfs_i(inode);
  35         unsigned n, disk_secno;
  36         struct fnode *fnode;
  37         struct buffer_head *bh;
  38         if (BLOCKS(hpfs_i(inode)->mmu_private) <= file_secno) return 0;
  39         n = file_secno - hpfs_inode->i_file_sec;
  40         if (n < hpfs_inode->i_n_secs) return hpfs_inode->i_disk_sec + n;
  41         if (!(fnode = hpfs_map_fnode(inode->i_sb, inode->i_ino, &bh))) return 0;
  42         disk_secno = hpfs_bplus_lookup(inode->i_sb, inode, &fnode->btree, file_secno, bh);
  43         if (disk_secno == -1) return 0;
  44         if (hpfs_chk_sectors(inode->i_sb, disk_secno, 1, "bmap")) return 0;
  45         return disk_secno;
  46 }
  47
  48 static void hpfs_truncate(struct inode *i)
  49 {
  50         if (IS_IMMUTABLE(i)) return /*-EPERM*/;
  51         hpfs_lock(i->i_sb);
  52         hpfs_i(i)->i_n_secs = 0;
  53         i->i_blocks = 1 + ((i->i_size + 511) >> 9);
  54         hpfs_i(i)->mmu_private = i->i_size;
  55         hpfs_truncate_btree(i->i_sb, i->i_ino, 1, ((i->i_size + 511) >> 9));
  56         hpfs_write_inode(i);
  57         hpfs_i(i)->i_n_secs = 0;
  58         hpfs_unlock(i->i_sb);
  59 }
  60
  61 static int hpfs_get_block(struct inode *inode, sector_t iblock, struct buffer_head *bh_result, int create)
  62 {
  63         secno s;
  64         s = hpfs_bmap(inode, iblock);
  65         if (s) {
  66                 map_bh(bh_result, inode->i_sb, s);
  67                 return 0;
  68         }
  69         if (!create) return 0;
  70         if (iblock<<9 != hpfs_i(inode)->mmu_private) {
  71                 BUG();
  72                 return -EIO;
  73         }
  74         if ((s = hpfs_add_sector_to_btree(inode->i_sb, inode->i_ino, 1, inode->i_blocks - 1)) == -1) {
  75                 hpfs_truncate_btree(inode->i_sb, inode->i_ino, 1, inode->i_blocks - 1);
  76                 return -ENOSPC;
  77         }
  78         inode->i_blocks++;
  79         hpfs_i(inode)->mmu_private += 512;
  80         set_buffer_new(bh_result);
  81         map_bh(bh_result, inode->i_sb, s);
  82         return 0;
  83 }
  84
  85 static int hpfs_writepage(struct page *page, struct writeback_control *wbc)
  86 {
  87         return block_write_full_page(page,hpfs_get_block, wbc);
  88 }
  89
  90 static int hpfs_readpage(struct file *file, struct page *page)
  91 {
  92         return block_read_full_page(page,hpfs_get_block);
  93 }
  94
  95 static int hpfs_write_begin(struct file *file, struct address_space *mapping,
  96                         loff_t pos, unsigned len, unsigned flags,
  97                         struct page **pagep, void **fsdata)
  98 {
  99         int ret;
 100
 101         *pagep = NULL;
 102         ret = cont_write_begin(file, mapping, pos, len, flags, pagep, fsdata,
 103                                 hpfs_get_block,
 104                                 &hpfs_i(mapping->host)->mmu_private);
 105         if (unlikely(ret)) {
 106                 loff_t isize = mapping->host->i_size;
 107                 if (pos + len > isize)
 108                         vmtruncate(mapping->host, isize);
 109         }
 110
 111         return ret;
 112 }
 113
 114 static sector_t _hpfs_bmap(struct address_space *mapping, sector_t block)
 115 {
 116         return generic_block_bmap(mapping,block,hpfs_get_block);
 117 }
 118
 119 const struct address_space_operations hpfs_aops = {
 120         .readpage = hpfs_readpage,
 121         .writepage = hpfs_writepage,
 122         .write_begin = hpfs_write_begin,
 123         .write_end = generic_write_end,
 124         .bmap = _hpfs_bmap
 125 };
 126
 127 static ssize_t hpfs_file_write(struct file *file, const char __user *buf,
 128                         size_t count, loff_t *ppos)
 129 {
 130         ssize_t retval;
 131
 132         retval = do_sync_write(file, buf, count, ppos);
 133         if (retval > 0)
 134                 hpfs_i(file->f_path.dentry->d_inode)->i_dirty = 1;
 135         return retval;
 136 }
 137
 138 const struct file_operations hpfs_file_ops =
 139 {
 140         .llseek         = generic_file_llseek,
 141         .read           = do_sync_read,
 142         .aio_read       = generic_file_aio_read,
 143         .write          = hpfs_file_write,
 144         .aio_write      = generic_file_aio_write,
 145         .mmap           = generic_file_mmap,
 146         .release        = hpfs_file_release,
 147         .fsync          = hpfs_file_fsync,
 148         .splice_read    = generic_file_splice_read,
 149 };
 150
 151 const struct inode_operations hpfs_file_iops =
 152 {
 153         .truncate       = hpfs_truncate,
 154         .setattr        = hpfs_setattr,
 155 };