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/pagemap.h>
  36 #include <linux/buffer_head.h>
  37 #include <linux/aio.h>
  38
  39 #include "udf_i.h"
  40 #include "udf_sb.h"
  41
  42 static void __udf_adinicb_readpage(struct page *page)
  43 {
  44         struct inode *inode = page->mapping->host;
  45         char *kaddr;
  46         struct udf_inode_info *iinfo = UDF_I(inode);
  47
  48         kaddr = kmap(page);
  49         memcpy(kaddr, iinfo->i_ext.i_data + iinfo->i_lenEAttr, inode->i_size);
  50         memset(kaddr + inode->i_size, 0, PAGE_CACHE_SIZE - inode->i_size);
  51         flush_dcache_page(page);
  52         SetPageUptodate(page);
  53         kunmap(page);
  54 }
  55
  56 static int udf_adinicb_readpage(struct file *file, struct page *page)
  57 {
  58         BUG_ON(!PageLocked(page));
  59         __udf_adinicb_readpage(page);
  60         unlock_page(page);
  61
  62         return 0;
  63 }
  64
  65 static int udf_adinicb_writepage(struct page *page,
  66                                  struct writeback_control *wbc)
  67 {
  68         struct inode *inode = page->mapping->host;
  69         char *kaddr;
  70         struct udf_inode_info *iinfo = UDF_I(inode);
  71
  72         BUG_ON(!PageLocked(page));
  73
  74         kaddr = kmap(page);
  75         memcpy(iinfo->i_ext.i_data + iinfo->i_lenEAttr, kaddr, inode->i_size);
  76         mark_inode_dirty(inode);
  77         SetPageUptodate(page);
  78         kunmap(page);
  79         unlock_page(page);
  80
  81         return 0;
  82 }
  83
  84 static int udf_adinicb_write_begin(struct file *file,
  85                         struct address_space *mapping, loff_t pos,
  86                         unsigned len, unsigned flags, struct page **pagep,
  87                         void **fsdata)
  88 {
  89         struct page *page;
  90
  91         if (WARN_ON_ONCE(pos >= PAGE_CACHE_SIZE))
  92                 return -EIO;
  93         page = grab_cache_page_write_begin(mapping, 0, flags);
  94         if (!page)
  95                 return -ENOMEM;
  96         *pagep = page;
  97
  98         if (!PageUptodate(page) && len != PAGE_CACHE_SIZE)
  99                 __udf_adinicb_readpage(page);
 100         return 0;
 101 }
 102
 103 static int udf_adinicb_write_end(struct file *file,
 104                         struct address_space *mapping,
 105                         loff_t pos, unsigned len, unsigned copied,
 106                         struct page *page, void *fsdata)
 107 {
 108         struct inode *inode = mapping->host;
 109         unsigned offset = pos & (PAGE_CACHE_SIZE - 1);
 110         char *kaddr;
 111         struct udf_inode_info *iinfo = UDF_I(inode);
 112
 113         kaddr = kmap_atomic(page);
 114         memcpy(iinfo->i_ext.i_data + iinfo->i_lenEAttr + offset,
 115                 kaddr + offset, copied);
 116         kunmap_atomic(kaddr);
 117
 118         return simple_write_end(file, mapping, pos, len, copied, page, fsdata);
 119 }
 120
 121 static ssize_t udf_adinicb_direct_IO(int rw, struct kiocb *iocb,
 122                                      const struct iovec *iov,
 123                                      loff_t offset, unsigned long nr_segs)
 124 {
 125         /* Fallback to buffered I/O. */
 126         return 0;
 127 }
 128
 129 const struct address_space_operations udf_adinicb_aops = {
 130         .readpage       = udf_adinicb_readpage,
 131         .writepage      = udf_adinicb_writepage,
 132         .write_begin    = udf_adinicb_write_begin,
 133         .write_end      = udf_adinicb_write_end,
 134         .direct_IO      = udf_adinicb_direct_IO,
 135 };
 136
 137 static ssize_t udf_file_aio_write(struct kiocb *iocb, const struct iovec *iov,
 138                                   unsigned long nr_segs, loff_t ppos)
 139 {
 140         ssize_t retval;
 141         struct file *file = iocb->ki_filp;
 142         struct inode *inode = file->f_path.dentry->d_inode;
 143         int err, pos;
 144         size_t count = iocb->ki_left;
 145         struct udf_inode_info *iinfo = UDF_I(inode);
 146
 147         down_write(&iinfo->i_data_sem);
 148         if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_IN_ICB) {
 149                 if (file->f_flags & O_APPEND)
 150                         pos = inode->i_size;
 151                 else
 152                         pos = ppos;
 153
 154                 if (inode->i_sb->s_blocksize <
 155                                 (udf_file_entry_alloc_offset(inode) +
 156                                                 pos + count)) {
 157                         err = udf_expand_file_adinicb(inode);
 158                         if (err) {
 159                                 udf_debug("udf_expand_adinicb: err=%d\n", err);
 160                                 return err;
 161                         }
 162                 } else {
 163                         if (pos + count > inode->i_size)
 164                                 iinfo->i_lenAlloc = pos + count;
 165                         else
 166                                 iinfo->i_lenAlloc = inode->i_size;
 167                         up_write(&iinfo->i_data_sem);
 168                 }
 169         } else
 170                 up_write(&iinfo->i_data_sem);
 171
 172         retval = generic_file_aio_write(iocb, iov, nr_segs, ppos);
 173         if (retval > 0)
 174                 mark_inode_dirty(inode);
 175
 176         return retval;
 177 }
 178
 179 long udf_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 180 {
 181         struct inode *inode = filp->f_dentry->d_inode;
 182         long old_block, new_block;
 183         int result = -EINVAL;
 184
 185         if (inode_permission(inode, MAY_READ) != 0) {
 186                 udf_debug("no permission to access inode %lu\n", inode->i_ino);
 187                 result = -EPERM;
 188                 goto out;
 189         }
 190
 191         if (!arg) {
 192                 udf_debug("invalid argument to udf_ioctl\n");
 193                 result = -EINVAL;
 194                 goto out;
 195         }
 196
 197         switch (cmd) {
 198         case UDF_GETVOLIDENT:
 199                 if (copy_to_user((char __user *)arg,
 200                                  UDF_SB(inode->i_sb)->s_volume_ident, 32))
 201                         result = -EFAULT;
 202                 else
 203                         result = 0;
 204                 goto out;
 205         case UDF_RELOCATE_BLOCKS:
 206                 if (!capable(CAP_SYS_ADMIN)) {
 207                         result = -EACCES;
 208                         goto out;
 209                 }
 210                 if (get_user(old_block, (long __user *)arg)) {
 211                         result = -EFAULT;
 212                         goto out;
 213                 }
 214                 result = udf_relocate_blocks(inode->i_sb,
 215                                                 old_block, &new_block);
 216                 if (result == 0)
 217                         result = put_user(new_block, (long __user *)arg);
 218                 goto out;
 219         case UDF_GETEASIZE:
 220                 result = put_user(UDF_I(inode)->i_lenEAttr, (int __user *)arg);
 221                 goto out;
 222         case UDF_GETEABLOCK:
 223                 result = copy_to_user((char __user *)arg,
 224                                       UDF_I(inode)->i_ext.i_data,
 225                                       UDF_I(inode)->i_lenEAttr) ? -EFAULT : 0;
 226                 goto out;
 227         }
 228
 229 out:
 230         return result;
 231 }
 232
 233 static int udf_release_file(struct inode *inode, struct file *filp)
 234 {
 235         if (filp->f_mode & FMODE_WRITE) {
 236                 down_write(&UDF_I(inode)->i_data_sem);
 237                 udf_discard_prealloc(inode);
 238                 udf_truncate_tail_extent(inode);
 239                 up_write(&UDF_I(inode)->i_data_sem);
 240         }
 241         return 0;
 242 }
 243
 244 const struct file_operations udf_file_operations = {
 245         .read                   = do_sync_read,
 246         .aio_read               = generic_file_aio_read,
 247         .unlocked_ioctl         = udf_ioctl,
 248         .open                   = generic_file_open,
 249         .mmap                   = generic_file_mmap,
 250         .write                  = do_sync_write,
 251         .aio_write              = udf_file_aio_write,
 252         .release                = udf_release_file,
 253         .fsync                  = generic_file_fsync,
 254         .splice_read            = generic_file_splice_read,
 255         .llseek                 = generic_file_llseek,
 256 };
 257
 258 static int udf_setattr(struct dentry *dentry, struct iattr *attr)
 259 {
 260         struct inode *inode = dentry->d_inode;
 261         int error;
 262
 263         error = inode_change_ok(inode, attr);
 264         if (error)
 265                 return error;
 266
 267         if ((attr->ia_valid & ATTR_SIZE) &&
 268             attr->ia_size != i_size_read(inode)) {
 269                 error = udf_setsize(inode, attr->ia_size);
 270                 if (error)
 271                         return error;
 272         }
 273
 274         setattr_copy(inode, attr);
 275         mark_inode_dirty(inode);
 276         return 0;
 277 }
 278
 279 const struct inode_operations udf_file_inode_operations = {
 280         .setattr                = udf_setattr,
 281 };