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         loff_t isize = i_size_read(inode);
  47
  48         /*
  49          * We have to be careful here as truncate can change i_size under us.
  50          * So just sample it once and use the same value everywhere.
  51          */
  52         kaddr = kmap_atomic(page);
  53         memcpy(kaddr, iinfo->i_data + iinfo->i_lenEAttr, isize);
  54         memset(kaddr + isize, 0, PAGE_SIZE - isize);
  55         flush_dcache_page(page);
  56         SetPageUptodate(page);
  57         kunmap_atomic(kaddr);
  58 }
  59
  60 static int udf_adinicb_readpage(struct file *file, struct page *page)
  61 {
  62         BUG_ON(!PageLocked(page));
  63         __udf_adinicb_readpage(page);
  64         unlock_page(page);
  65
  66         return 0;
  67 }
  68
  69 static int udf_adinicb_writepage(struct page *page,
  70                                  struct writeback_control *wbc)
  71 {
  72         struct inode *inode = page->mapping->host;
  73         char *kaddr;
  74         struct udf_inode_info *iinfo = UDF_I(inode);
  75
  76         BUG_ON(!PageLocked(page));
  77
  78         kaddr = kmap_atomic(page);
  79         memcpy(iinfo->i_data + iinfo->i_lenEAttr, kaddr, i_size_read(inode));
  80         SetPageUptodate(page);
  81         kunmap_atomic(kaddr);
  82         mark_inode_dirty(inode);
  83         unlock_page(page);
  84
  85         return 0;
  86 }
  87
  88 static int udf_adinicb_write_begin(struct file *file,
  89                         struct address_space *mapping, loff_t pos,
  90                         unsigned len, unsigned flags, struct page **pagep,
  91                         void **fsdata)
  92 {
  93         struct page *page;
  94
  95         if (WARN_ON_ONCE(pos >= PAGE_SIZE))
  96                 return -EIO;
  97         page = grab_cache_page_write_begin(mapping, 0, flags);
  98         if (!page)
  99                 return -ENOMEM;
 100         *pagep = page;
 101
 102         if (!PageUptodate(page))
 103                 __udf_adinicb_readpage(page);
 104         return 0;
 105 }
 106
 107 static ssize_t udf_adinicb_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
 108 {
 109         /* Fallback to buffered I/O. */
 110         return 0;
 111 }
 112
 113 static int udf_adinicb_write_end(struct file *file, struct address_space *mapping,
 114                                  loff_t pos, unsigned len, unsigned copied,
 115                                  struct page *page, void *fsdata)
 116 {
 117         struct inode *inode = page->mapping->host;
 118         loff_t last_pos = pos + copied;
 119         if (last_pos > inode->i_size)
 120                 i_size_write(inode, last_pos);
 121         set_page_dirty(page);
 122         unlock_page(page);
 123         put_page(page);
 124         return copied;
 125 }
 126
 127 const struct address_space_operations udf_adinicb_aops = {
 128         .readpage       = udf_adinicb_readpage,
 129         .writepage      = udf_adinicb_writepage,
 130         .write_begin    = udf_adinicb_write_begin,
 131         .write_end      = udf_adinicb_write_end,
 132         .direct_IO      = udf_adinicb_direct_IO,
 133 };
 134
 135 static ssize_t udf_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
 136 {
 137         ssize_t retval;
 138         struct file *file = iocb->ki_filp;
 139         struct inode *inode = file_inode(file);
 140         struct udf_inode_info *iinfo = UDF_I(inode);
 141         int err;
 142
 143         inode_lock(inode);
 144
 145         retval = generic_write_checks(iocb, from);
 146         if (retval <= 0)
 147                 goto out;
 148
 149         down_write(&iinfo->i_data_sem);
 150         if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_IN_ICB &&
 151             inode->i_sb->s_blocksize < (udf_file_entry_alloc_offset(inode) +
 152                                  iocb->ki_pos + iov_iter_count(from))) {
 153                 err = udf_expand_file_adinicb(inode);
 154                 if (err) {
 155                         inode_unlock(inode);
 156                         udf_debug("udf_expand_adinicb: err=%d\n", err);
 157                         return err;
 158                 }
 159         } else
 160                 up_write(&iinfo->i_data_sem);
 161
 162         retval = __generic_file_write_iter(iocb, from);
 163 out:
 164         down_write(&iinfo->i_data_sem);
 165         if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_IN_ICB && retval > 0)
 166                 iinfo->i_lenAlloc = inode->i_size;
 167         up_write(&iinfo->i_data_sem);
 168         inode_unlock(inode);
 169
 170         if (retval > 0) {
 171                 mark_inode_dirty(inode);
 172                 retval = generic_write_sync(iocb, retval);
 173         }
 174
 175         return retval;
 176 }
 177
 178 long udf_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 179 {
 180         struct inode *inode = file_inode(filp);
 181         long old_block, new_block;
 182         int result;
 183
 184         if (inode_permission(inode, MAY_READ) != 0) {
 185                 udf_debug("no permission to access inode %lu\n", inode->i_ino);
 186                 return -EPERM;
 187         }
 188
 189         if (!arg && ((cmd == UDF_GETVOLIDENT) || (cmd == UDF_GETEASIZE) ||
 190                      (cmd == UDF_RELOCATE_BLOCKS) || (cmd == UDF_GETEABLOCK))) {
 191                 udf_debug("invalid argument to udf_ioctl\n");
 192                 return -EINVAL;
 193         }
 194
 195         switch (cmd) {
 196         case UDF_GETVOLIDENT:
 197                 if (copy_to_user((char __user *)arg,
 198                                  UDF_SB(inode->i_sb)->s_volume_ident, 32))
 199                         return -EFAULT;
 200                 return 0;
 201         case UDF_RELOCATE_BLOCKS:
 202                 if (!capable(CAP_SYS_ADMIN))
 203                         return -EPERM;
 204                 if (get_user(old_block, (long __user *)arg))
 205                         return -EFAULT;
 206                 result = udf_relocate_blocks(inode->i_sb,
 207                                                 old_block, &new_block);
 208                 if (result == 0)
 209                         result = put_user(new_block, (long __user *)arg);
 210                 return result;
 211         case UDF_GETEASIZE:
 212                 return put_user(UDF_I(inode)->i_lenEAttr, (int __user *)arg);
 213         case UDF_GETEABLOCK:
 214                 return copy_to_user((char __user *)arg,
 215                                     UDF_I(inode)->i_data,
 216                                     UDF_I(inode)->i_lenEAttr) ? -EFAULT : 0;
 217         default:
 218                 return -ENOIOCTLCMD;
 219         }
 220
 221         return 0;
 222 }
 223
 224 static int udf_release_file(struct inode *inode, struct file *filp)
 225 {
 226         if (filp->f_mode & FMODE_WRITE &&
 227             atomic_read(&inode->i_writecount) == 1) {
 228                 /*
 229                  * Grab i_mutex to avoid races with writes changing i_size
 230                  * while we are running.
 231                  */
 232                 inode_lock(inode);
 233                 down_write(&UDF_I(inode)->i_data_sem);
 234                 udf_discard_prealloc(inode);
 235                 udf_truncate_tail_extent(inode);
 236                 up_write(&UDF_I(inode)->i_data_sem);
 237                 inode_unlock(inode);
 238         }
 239         return 0;
 240 }
 241
 242 const struct file_operations udf_file_operations = {
 243         .read_iter              = generic_file_read_iter,
 244         .unlocked_ioctl         = udf_ioctl,
 245         .open                   = generic_file_open,
 246         .mmap                   = generic_file_mmap,
 247         .write_iter             = udf_file_write_iter,
 248         .release                = udf_release_file,
 249         .fsync                  = generic_file_fsync,
 250         .splice_read            = generic_file_splice_read,
 251         .llseek                 = generic_file_llseek,
 252 };
 253
 254 static int udf_setattr(struct dentry *dentry, struct iattr *attr)
 255 {
 256         struct inode *inode = d_inode(dentry);
 257         struct super_block *sb = inode->i_sb;
 258         int error;
 259
 260         error = setattr_prepare(dentry, attr);
 261         if (error)
 262                 return error;
 263
 264         if ((attr->ia_valid & ATTR_UID) &&
 265             UDF_QUERY_FLAG(sb, UDF_FLAG_UID_SET) &&
 266             !uid_eq(attr->ia_uid, UDF_SB(sb)->s_uid))
 267                 return -EPERM;
 268         if ((attr->ia_valid & ATTR_GID) &&
 269             UDF_QUERY_FLAG(sb, UDF_FLAG_GID_SET) &&
 270             !gid_eq(attr->ia_gid, UDF_SB(sb)->s_gid))
 271                 return -EPERM;
 272
 273         if ((attr->ia_valid & ATTR_SIZE) &&
 274             attr->ia_size != i_size_read(inode)) {
 275                 error = udf_setsize(inode, attr->ia_size);
 276                 if (error)
 277                         return error;
 278         }
 279
 280         if (attr->ia_valid & ATTR_MODE)
 281                 udf_update_extra_perms(inode, attr->ia_mode);
 282
 283         setattr_copy(inode, attr);
 284         mark_inode_dirty(inode);
 285         return 0;
 286 }
 287
 288 const struct inode_operations udf_file_inode_operations = {
 289         .setattr                = udf_setattr,
 290 };