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