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_ext.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_ext.i_data + iinfo->i_lenEAttr, kaddr,
  80                 i_size_read(inode));
  81         SetPageUptodate(page);
  82         kunmap_atomic(kaddr);
  83         mark_inode_dirty(inode);
  84         unlock_page(page);
  85
  86         return 0;
  87 }
  88
  89 static int udf_adinicb_write_begin(struct file *file,
  90                         struct address_space *mapping, loff_t pos,
  91                         unsigned len, unsigned flags, struct page **pagep,
  92                         void **fsdata)
  93 {
  94         struct page *page;
  95
  96         if (WARN_ON_ONCE(pos >= PAGE_SIZE))
  97                 return -EIO;
  98         page = grab_cache_page_write_begin(mapping, 0, flags);
  99         if (!page)
 100                 return -ENOMEM;
 101         *pagep = page;
 102
 103         if (!PageUptodate(page))
 104                 __udf_adinicb_readpage(page);
 105         return 0;
 106 }
 107
 108 static ssize_t udf_adinicb_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
 109 {
 110         /* Fallback to buffered I/O. */
 111         return 0;
 112 }
 113
 114 static int udf_adinicb_write_end(struct file *file, struct address_space *mapping,
 115                                  loff_t pos, unsigned len, unsigned copied,
 116                                  struct page *page, void *fsdata)
 117 {
 118         struct inode *inode = page->mapping->host;
 119         loff_t last_pos = pos + copied;
 120         if (last_pos > inode->i_size)
 121                 i_size_write(inode, last_pos);
 122         set_page_dirty(page);
 123         unlock_page(page);
 124         put_page(page);
 125         return copied;
 126 }
 127
 128 const struct address_space_operations udf_adinicb_aops = {
 129         .readpage       = udf_adinicb_readpage,
 130         .writepage      = udf_adinicb_writepage,
 131         .write_begin    = udf_adinicb_write_begin,
 132         .write_end      = udf_adinicb_write_end,
 133         .direct_IO      = udf_adinicb_direct_IO,
 134 };
 135
 136 static ssize_t udf_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
 137 {
 138         ssize_t retval;
 139         struct file *file = iocb->ki_filp;
 140         struct inode *inode = file_inode(file);
 141         struct udf_inode_info *iinfo = UDF_I(inode);
 142         int err;
 143
 144         inode_lock(inode);
 145
 146         retval = generic_write_checks(iocb, from);
 147         if (retval <= 0)
 148                 goto out;
 149
 150         down_write(&iinfo->i_data_sem);
 151         if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_IN_ICB) {
 152                 loff_t end = iocb->ki_pos + iov_iter_count(from);
 153
 154                 if (inode->i_sb->s_blocksize <
 155                                 (udf_file_entry_alloc_offset(inode) + end)) {
 156                         err = udf_expand_file_adinicb(inode);
 157                         if (err) {
 158                                 inode_unlock(inode);
 159                                 udf_debug("udf_expand_adinicb: err=%d\n", err);
 160                                 return err;
 161                         }
 162                 } else {
 163                         iinfo->i_lenAlloc = max(end, inode->i_size);
 164                         up_write(&iinfo->i_data_sem);
 165                 }
 166         } else
 167                 up_write(&iinfo->i_data_sem);
 168
 169         retval = __generic_file_write_iter(iocb, from);
 170 out:
 171         inode_unlock(inode);
 172
 173         if (retval > 0) {
 174                 mark_inode_dirty(inode);
 175                 retval = generic_write_sync(iocb, retval);
 176         }
 177
 178         return retval;
 179 }
 180
 181 long udf_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 182 {
 183         struct inode *inode = file_inode(filp);
 184         long old_block, new_block;
 185         int result;
 186
 187         if (inode_permission(inode, MAY_READ) != 0) {
 188                 udf_debug("no permission to access inode %lu\n", inode->i_ino);
 189                 return -EPERM;
 190         }
 191
 192         if (!arg && ((cmd == UDF_GETVOLIDENT) || (cmd == UDF_GETEASIZE) ||
 193                      (cmd == UDF_RELOCATE_BLOCKS) || (cmd == UDF_GETEABLOCK))) {
 194                 udf_debug("invalid argument to udf_ioctl\n");
 195                 return -EINVAL;
 196         }
 197
 198         switch (cmd) {
 199         case UDF_GETVOLIDENT:
 200                 if (copy_to_user((char __user *)arg,
 201                                  UDF_SB(inode->i_sb)->s_volume_ident, 32))
 202                         return -EFAULT;
 203                 return 0;
 204         case UDF_RELOCATE_BLOCKS:
 205                 if (!capable(CAP_SYS_ADMIN))
 206                         return -EPERM;
 207                 if (get_user(old_block, (long __user *)arg))
 208                         return -EFAULT;
 209                 result = udf_relocate_blocks(inode->i_sb,
 210                                                 old_block, &new_block);
 211                 if (result == 0)
 212                         result = put_user(new_block, (long __user *)arg);
 213                 return result;
 214         case UDF_GETEASIZE:
 215                 return put_user(UDF_I(inode)->i_lenEAttr, (int __user *)arg);
 216         case UDF_GETEABLOCK:
 217                 return copy_to_user((char __user *)arg,
 218                                     UDF_I(inode)->i_ext.i_data,
 219                                     UDF_I(inode)->i_lenEAttr) ? -EFAULT : 0;
 220         default:
 221                 return -ENOIOCTLCMD;
 222         }
 223
 224         return 0;
 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                 inode_lock(inode);
 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                 inode_unlock(inode);
 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 = d_inode(dentry);
 260         struct super_block *sb = inode->i_sb;
 261         int error;
 262
 263         error = setattr_prepare(dentry, attr);
 264         if (error)
 265                 return error;
 266
 267         if ((attr->ia_valid & ATTR_UID) &&
 268             UDF_QUERY_FLAG(sb, UDF_FLAG_UID_SET) &&
 269             !uid_eq(attr->ia_uid, UDF_SB(sb)->s_uid))
 270                 return -EPERM;
 271         if ((attr->ia_valid & ATTR_GID) &&
 272             UDF_QUERY_FLAG(sb, UDF_FLAG_GID_SET) &&
 273             !gid_eq(attr->ia_gid, UDF_SB(sb)->s_gid))
 274                 return -EPERM;
 275
 276         if ((attr->ia_valid & ATTR_SIZE) &&
 277             attr->ia_size != i_size_read(inode)) {
 278                 error = udf_setsize(inode, attr->ia_size);
 279                 if (error)
 280                         return error;
 281         }
 282
 283         if (attr->ia_valid & ATTR_MODE)
 284                 udf_update_extra_perms(inode, attr->ia_mode);
 285
 286         setattr_copy(inode, attr);
 287         mark_inode_dirty(inode);
 288         return 0;
 289 }
 290
 291 const struct inode_operations udf_file_inode_operations = {
 292         .setattr                = udf_setattr,
 293 };