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 <linux/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/uio.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 ssize_t udf_adinicb_direct_IO(struct kiocb *iocb, struct iov_iter *iter,
 104                                      loff_t offset)
 105 {
 106         /* Fallback to buffered I/O. */
 107         return 0;
 108 }
 109
 110 const struct address_space_operations udf_adinicb_aops = {
 111         .readpage       = udf_adinicb_readpage,
 112         .writepage      = udf_adinicb_writepage,
 113         .write_begin    = udf_adinicb_write_begin,
 114         .write_end      = simple_write_end,
 115         .direct_IO      = udf_adinicb_direct_IO,
 116 };
 117
 118 static ssize_t udf_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
 119 {
 120         ssize_t retval;
 121         struct file *file = iocb->ki_filp;
 122         struct inode *inode = file_inode(file);
 123         size_t count = iov_iter_count(from);
 124         struct udf_inode_info *iinfo = UDF_I(inode);
 125         int err;
 126
 127         mutex_lock(&inode->i_mutex);
 128
 129         retval = generic_write_checks(file, &iocb->ki_pos, &count);
 130         if (retval)
 131                 goto out;
 132
 133         if (count == 0)
 134                 goto out;
 135
 136         iov_iter_truncate(from, count);
 137
 138         down_write(&iinfo->i_data_sem);
 139         if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_IN_ICB) {
 140                 loff_t end = iocb->ki_pos + iov_iter_count(from);
 141
 142                 if (inode->i_sb->s_blocksize <
 143                                 (udf_file_entry_alloc_offset(inode) + end)) {
 144                         err = udf_expand_file_adinicb(inode);
 145                         if (err) {
 146                                 mutex_unlock(&inode->i_mutex);
 147                                 udf_debug("udf_expand_adinicb: err=%d\n", err);
 148                                 return err;
 149                         }
 150                 } else {
 151                         iinfo->i_lenAlloc = max(end, inode->i_size);
 152                         up_write(&iinfo->i_data_sem);
 153                 }
 154         } else
 155                 up_write(&iinfo->i_data_sem);
 156
 157         retval = __generic_file_write_iter(iocb, from);
 158 out:
 159         mutex_unlock(&inode->i_mutex);
 160
 161         if (retval > 0) {
 162                 ssize_t err;
 163
 164                 mark_inode_dirty(inode);
 165                 err = generic_write_sync(file, iocb->ki_pos - retval, retval);
 166                 if (err < 0)
 167                         retval = err;
 168         }
 169
 170         return retval;
 171 }
 172
 173 long udf_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 174 {
 175         struct inode *inode = file_inode(filp);
 176         long old_block, new_block;
 177         int result = -EINVAL;
 178
 179         if (inode_permission(inode, MAY_READ) != 0) {
 180                 udf_debug("no permission to access inode %lu\n", inode->i_ino);
 181                 result = -EPERM;
 182                 goto out;
 183         }
 184
 185         if (!arg) {
 186                 udf_debug("invalid argument to udf_ioctl\n");
 187                 result = -EINVAL;
 188                 goto out;
 189         }
 190
 191         switch (cmd) {
 192         case UDF_GETVOLIDENT:
 193                 if (copy_to_user((char __user *)arg,
 194                                  UDF_SB(inode->i_sb)->s_volume_ident, 32))
 195                         result = -EFAULT;
 196                 else
 197                         result = 0;
 198                 goto out;
 199         case UDF_RELOCATE_BLOCKS:
 200                 if (!capable(CAP_SYS_ADMIN)) {
 201                         result = -EPERM;
 202                         goto out;
 203                 }
 204                 if (get_user(old_block, (long __user *)arg)) {
 205                         result = -EFAULT;
 206                         goto out;
 207                 }
 208                 result = udf_relocate_blocks(inode->i_sb,
 209                                                 old_block, &new_block);
 210                 if (result == 0)
 211                         result = put_user(new_block, (long __user *)arg);
 212                 goto out;
 213         case UDF_GETEASIZE:
 214                 result = put_user(UDF_I(inode)->i_lenEAttr, (int __user *)arg);
 215                 goto out;
 216         case UDF_GETEABLOCK:
 217                 result = copy_to_user((char __user *)arg,
 218                                       UDF_I(inode)->i_ext.i_data,
 219                                       UDF_I(inode)->i_lenEAttr) ? -EFAULT : 0;
 220                 goto out;
 221         }
 222
 223 out:
 224         return result;
 225 }
 226
 227 static int udf_release_file(struct inode *inode, struct file *filp)
 228 {
 229         if (filp->f_mode & FMODE_WRITE &&
 230             atomic_read(&inode->i_writecount) == 1) {
 231                 /*
 232                  * Grab i_mutex to avoid races with writes changing i_size
 233                  * while we are running.
 234                  */
 235                 mutex_lock(&inode->i_mutex);
 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                 mutex_unlock(&inode->i_mutex);
 241         }
 242         return 0;
 243 }
 244
 245 const struct file_operations udf_file_operations = {
 246         .read_iter              = generic_file_read_iter,
 247         .unlocked_ioctl         = udf_ioctl,
 248         .open                   = generic_file_open,
 249         .mmap                   = generic_file_mmap,
 250         .write_iter             = udf_file_write_iter,
 251         .release                = udf_release_file,
 252         .fsync                  = generic_file_fsync,
 253         .splice_read            = generic_file_splice_read,
 254         .llseek                 = generic_file_llseek,
 255 };
 256
 257 static int udf_setattr(struct dentry *dentry, struct iattr *attr)
 258 {
 259         struct inode *inode = dentry->d_inode;
 260         int error;
 261
 262         error = inode_change_ok(inode, attr);
 263         if (error)
 264                 return error;
 265
 266         if ((attr->ia_valid & ATTR_SIZE) &&
 267             attr->ia_size != i_size_read(inode)) {
 268                 error = udf_setsize(inode, attr->ia_size);
 269                 if (error)
 270                         return error;
 271         }
 272
 273         setattr_copy(inode, attr);
 274         mark_inode_dirty(inode);
 275         return 0;
 276 }
 277
 278 const struct inode_operations udf_file_inode_operations = {
 279         .setattr                = udf_setattr,
 280 };