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 <linux/string.h>
  10 #include "hpfs_fn.h"
  11
  12 int hpfs_open(struct inode *i, struct file *f)
  13 {
  14         hpfs_lock_inode(i);
  15         hpfs_unlock_inode(i); /* make sure nobody is deleting the file */
  16         if (!i->i_nlink) return -ENOENT;
  17         return 0;
  18 }
  19
  20 int hpfs_file_release(struct inode *inode, struct file *file)
  21 {
  22         hpfs_write_if_changed(inode);
  23         return 0;
  24 }
  25
  26 int hpfs_file_fsync(struct file *file, struct dentry *dentry)
  27 {
  28         /*return file_fsync(file, dentry);*/
  29         return 0; /* Don't fsync :-) */
  30 }
  31
  32 /*
  33  * generic_file_read often calls bmap with non-existing sector,
  34  * so we must ignore such errors.
  35  */
  36
  37 secno hpfs_bmap(struct inode *inode, unsigned file_secno)
  38 {
  39         unsigned n, disk_secno;
  40         struct fnode *fnode;
  41         struct buffer_head *bh;
  42         if (((inode->i_size + 511) >> 9) <= file_secno) return 0;
  43         n = file_secno - inode->i_hpfs_file_sec;
  44         if (n < inode->i_hpfs_n_secs) return inode->i_hpfs_disk_sec + n;
  45         if (!(fnode = hpfs_map_fnode(inode->i_sb, inode->i_ino, &bh))) return 0;
  46         disk_secno = hpfs_bplus_lookup(inode->i_sb, inode, &fnode->btree, file_secno, bh);
  47         if (disk_secno == -1) return 0;
  48         if (hpfs_chk_sectors(inode->i_sb, disk_secno, 1, "bmap")) return 0;
  49         return disk_secno;
  50 }
  51
  52 void hpfs_truncate(struct inode *i)
  53 {
  54         if (IS_IMMUTABLE(i)) return /*-EPERM*/;
  55         i->i_hpfs_n_secs = 0;
  56         i->i_blocks = 1 + ((i->i_size + 511) >> 9);
  57         i->u.hpfs_i.mmu_private = i->i_size;
  58         hpfs_truncate_btree(i->i_sb, i->i_ino, 1, ((i->i_size + 511) >> 9));
  59         hpfs_write_inode(i);
  60 }
  61
  62 int hpfs_get_block(struct inode *inode, long iblock, struct buffer_head *bh_result, int create)
  63 {
  64         secno s;
  65         s = hpfs_bmap(inode, iblock);
  66         if (s) {
  67                 bh_result->b_dev = inode->i_dev;
  68                 bh_result->b_blocknr = s;
  69                 bh_result->b_state |= (1UL << BH_Mapped);
  70                 return 0;
  71         }
  72         if (!create) return 0;
  73         if (iblock<<9 != inode->u.hpfs_i.mmu_private) {
  74                 BUG();
  75                 return -EIO;
  76         }
  77         if ((s = hpfs_add_sector_to_btree(inode->i_sb, inode->i_ino, 1, inode->i_blocks - 1)) == -1) {
  78                 hpfs_truncate_btree(inode->i_sb, inode->i_ino, 1, inode->i_blocks - 1);
  79                 return -ENOSPC;
  80         }
  81         inode->i_blocks++;
  82         inode->u.hpfs_i.mmu_private += 512;
  83         bh_result->b_dev = inode->i_dev;
  84         bh_result->b_blocknr = s;
  85         bh_result->b_state |= (1UL << BH_Mapped) | (1UL << BH_New);
  86         return 0;
  87 }
  88
  89 static int hpfs_writepage(struct file *file, struct page *page)
  90 {
  91         return block_write_full_page(page,hpfs_get_block);
  92 }
  93 static int hpfs_readpage(struct file *file, struct page *page)
  94 {
  95         return block_read_full_page(page,hpfs_get_block);
  96 }
  97 static int hpfs_prepare_write(struct file *file, struct page *page, unsigned from, unsigned to)
  98 {
  99         return cont_prepare_write(page,from,to,hpfs_get_block,
 100                 &((struct inode*)page->mapping->host)->u.hpfs_i.mmu_private);
 101 }
 102 static int _hpfs_bmap(struct address_space *mapping, long block)
 103 {
 104         return generic_block_bmap(mapping,block,hpfs_get_block);
 105 }
 106 struct address_space_operations hpfs_aops = {
 107         readpage: hpfs_readpage,
 108         writepage: hpfs_writepage,
 109         sync_page: block_sync_page,
 110         prepare_write: hpfs_prepare_write,
 111         commit_write: generic_commit_write,
 112         bmap: _hpfs_bmap
 113 };
 114
 115 ssize_t hpfs_file_write(struct file *file, const char *buf, size_t count, loff_t *ppos)
 116 {
 117         ssize_t retval;
 118
 119         retval = generic_file_write(file, buf, count, ppos);
 120         if (retval > 0) {
 121                 struct inode *inode = file->f_dentry->d_inode;
 122                 inode->i_mtime = CURRENT_TIME;
 123                 inode->i_hpfs_dirty = 1;
 124         }
 125         return retval;
 126 }
 127