fs/udf/file.c

   1 /*
   2  * file.c
   3  *
   4  * PURPOSE
   5  *  File handling routines for the OSTA-UDF(tm) filesystem.
   6  *
   7  * COPYRIGHT
   8  *  This file is distributed under the terms of the GNU General Public
   9  *  License (GPL). Copies of the GPL can be obtained from:
  10  *    ftp://prep.ai.mit.edu/pub/gnu/GPL
  11  *  Each contributing author retains all rights to their own work.
  12  *
  13  *  (C) 1998-1999 Dave Boynton
  14  *  (C) 1998-2004 Ben Fennema
  15  *  (C) 1999-2000 Stelias Computing Inc
  16  *
  17  * HISTORY
  18  *
  19  *  10/02/98 dgb  Attempt to integrate into udf.o
  20  *  10/07/98      Switched to using generic_readpage, etc., like isofs
  21  *                And it works!
  22  *  12/06/98 blf  Added udf_file_read. uses generic_file_read for all cases but
  23  *                ICBTAG_FLAG_AD_IN_ICB.
  24  *  04/06/99      64 bit file handling on 32 bit systems taken from ext2 file.c
  25  *  05/12/99      Preliminary file write support
  26  */
  27
  28 #include "udfdecl.h"
  29 #include <linux/fs.h>
  30 #include <asm/uaccess.h>
  31 #include <linux/kernel.h>
  32 #include <linux/string.h> /* memset */
  33 #include <linux/capability.h>
  34 #include <linux/errno.h>
  35 #include <linux/smp_lock.h>
  36 #include <linux/pagemap.h>
  37 #include <linux/buffer_head.h>
  38 #include <linux/aio.h>
  39
  40 #include "udf_i.h"
  41 #include "udf_sb.h"
  42
  43 static void __udf_adinicb_readpage(struct page *page)
  44 {
  45         struct inode *inode = page->mapping->host;
  46         char *kaddr;
  47         struct udf_inode_info *iinfo = UDF_I(inode);
  48
  49         kaddr = kmap(page);
  50         memcpy(kaddr, iinfo->i_ext.i_data + iinfo->i_lenEAttr, inode->i_size);
  51         memset(kaddr + inode->i_size, 0, PAGE_CACHE_SIZE - inode->i_size);
  52         flush_dcache_page(page);
  53         SetPageUptodate(page);
  54         kunmap(page);
  55 }
  56
  57 static int udf_adinicb_readpage(struct file *file, struct page *page)
  58 {
  59         BUG_ON(!PageLocked(page));
  60         __udf_adinicb_readpage(page);
  61         unlock_page(page);
  62
  63         return 0;
  64 }
  65
  66 static int udf_adinicb_writepage(struct page *page,
  67                                  struct writeback_control *wbc)
  68 {
  69         struct inode *inode = page->mapping->host;
  70         char *kaddr;
  71         struct udf_inode_info *iinfo = UDF_I(inode);
  72
  73         BUG_ON(!PageLocked(page));
  74
  75         kaddr = kmap(page);
  76         memcpy(iinfo->i_ext.i_data + iinfo->i_lenEAttr, kaddr, inode->i_size);
  77         mark_inode_dirty(inode);
  78         SetPageUptodate(page);
  79         kunmap(page);
  80         unlock_page(page);
  81
  82         return 0;
  83 }
  84
  85 static int udf_adinicb_write_begin(struct file *file,
  86                         struct address_space *mapping, loff_t pos,
  87                         unsigned len, unsigned flags, struct page **pagep,
  88                         void **fsdata)
  89 {
  90         struct page *page;
  91
  92         if (WARN_ON_ONCE(pos >= PAGE_CACHE_SIZE))
  93                 return -EIO;
  94         page = grab_cache_page_write_begin(mapping, 0, flags);
  95         if (!page)
  96                 return -ENOMEM;
  97         *pagep = page;
  98
  99         if (!PageUptodate(page) && len != PAGE_CACHE_SIZE)
 100                 __udf_adinicb_readpage(page);
 101         return 0;
 102 }
 103
 104 static int udf_adinicb_write_end(struct file *file,
 105                         struct address_space *mapping,
 106                         loff_t pos, unsigned len, unsigned copied,
 107                         struct page *page, void *fsdata)
 108 {
 109         struct inode *inode = mapping->host;
 110         unsigned offset = pos & (PAGE_CACHE_SIZE - 1);
 111         char *kaddr;
 112         struct udf_inode_info *iinfo = UDF_I(inode);
 113
 114         kaddr = kmap_atomic(page, KM_USER0);
 115         memcpy(iinfo->i_ext.i_data + iinfo->i_lenEAttr + offset,
 116                 kaddr + offset, copied);
 117         kunmap_atomic(kaddr, KM_USER0);
 118
 119         return simple_write_end(file, mapping, pos, len, copied, page, fsdata);
 120 }
 121
 122 const struct address_space_operations udf_adinicb_aops = {
 123         .readpage       = udf_adinicb_readpage,
 124         .writepage      = udf_adinicb_writepage,
 125         .sync_page      = block_sync_page,
 126         .write_begin    = udf_adinicb_write_begin,
 127         .write_end      = udf_adinicb_write_end,
 128 };
 129
 130 static ssize_t udf_file_aio_write(struct kiocb *iocb, const struct iovec *iov,
 131                                   unsigned long nr_segs, loff_t ppos)
 132 {
 133         ssize_t retval;
 134         struct file *file = iocb->ki_filp;
 135         struct inode *inode = file->f_path.dentry->d_inode;
 136         int err, pos;
 137         size_t count = iocb->ki_left;
 138         struct udf_inode_info *iinfo = UDF_I(inode);
 139
 140         if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_IN_ICB) {
 141                 if (file->f_flags & O_APPEND)
 142                         pos = inode->i_size;
 143                 else
 144                         pos = ppos;
 145
 146                 if (inode->i_sb->s_blocksize <
 147                                 (udf_file_entry_alloc_offset(inode) +
 148                                                 pos + count)) {
 149                         udf_expand_file_adinicb(inode, pos + count, &err);
 150                         if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_IN_ICB) {
 151                                 udf_debug("udf_expand_adinicb: err=%d\n", err);
 152                                 return err;
 153                         }
 154                 } else {
 155                         if (pos + count > inode->i_size)
 156                                 iinfo->i_lenAlloc = pos + count;
 157                         else
 158                                 iinfo->i_lenAlloc = inode->i_size;
 159                 }
 160         }
 161
 162         retval = generic_file_aio_write(iocb, iov, nr_segs, ppos);
 163         if (retval > 0)
 164                 mark_inode_dirty(inode);
 165
 166         return retval;
 167 }
 168
 169 int udf_ioctl(struct inode *inode, struct file *filp, unsigned int cmd,
 170               unsigned long arg)
 171 {
 172         long old_block, new_block;
 173         int result = -EINVAL;
 174
 175         if (file_permission(filp, MAY_READ) != 0) {
 176                 udf_debug("no permission to access inode %lu\n",
 177                           inode->i_ino);
 178                 return -EPERM;
 179         }
 180
 181         if (!arg) {
 182                 udf_debug("invalid argument to udf_ioctl\n");
 183                 return -EINVAL;
 184         }
 185
 186         switch (cmd) {
 187         case UDF_GETVOLIDENT:
 188                 if (copy_to_user((char __user *)arg,
 189                                  UDF_SB(inode->i_sb)->s_volume_ident, 32))
 190                         return -EFAULT;
 191                 else
 192                         return 0;
 193         case UDF_RELOCATE_BLOCKS:
 194                 if (!capable(CAP_SYS_ADMIN))
 195                         return -EACCES;
 196                 if (get_user(old_block, (long __user *)arg))
 197                         return -EFAULT;
 198                 result = udf_relocate_blocks(inode->i_sb,
 199                                                 old_block, &new_block);
 200                 if (result == 0)
 201                         result = put_user(new_block, (long __user *)arg);
 202                 return result;
 203         case UDF_GETEASIZE:
 204                 result = put_user(UDF_I(inode)->i_lenEAttr, (int __user *)arg);
 205                 break;
 206         case UDF_GETEABLOCK:
 207                 result = copy_to_user((char __user *)arg,
 208                                       UDF_I(inode)->i_ext.i_data,
 209                                       UDF_I(inode)->i_lenEAttr) ? -EFAULT : 0;
 210                 break;
 211         }
 212
 213         return result;
 214 }
 215
 216 static int udf_release_file(struct inode *inode, struct file *filp)
 217 {
 218         if (filp->f_mode & FMODE_WRITE) {
 219                 mutex_lock(&inode->i_mutex);
 220                 lock_kernel();
 221                 udf_discard_prealloc(inode);
 222                 unlock_kernel();
 223                 mutex_unlock(&inode->i_mutex);
 224         }
 225         return 0;
 226 }
 227
 228 const struct file_operations udf_file_operations = {
 229         .read                   = do_sync_read,
 230         .aio_read               = generic_file_aio_read,
 231         .ioctl                  = udf_ioctl,
 232         .open                   = generic_file_open,
 233         .mmap                   = generic_file_mmap,
 234         .write                  = do_sync_write,
 235         .aio_write              = udf_file_aio_write,
 236         .release                = udf_release_file,
 237         .fsync                  = simple_fsync,
 238         .splice_read            = generic_file_splice_read,
 239         .llseek                 = generic_file_llseek,
 240 };
 241
 242 const struct inode_operations udf_file_inode_operations = {
 243         .truncate = udf_truncate,
 244 };