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         loff_t isize = i_size_read(inode);
  48
  49         /*
  50          * We have to be careful here as truncate can change i_size under us.
  51          * So just sample it once and use the same value everywhere.
  52          */
  53         kaddr = kmap(page);
  54         memcpy(kaddr, iinfo->i_ext.i_data + iinfo->i_lenEAttr, isize);
  55         memset(kaddr + isize, 0, PAGE_CACHE_SIZE - isize);
  56         flush_dcache_page(page);
  57         SetPageUptodate(page);
  58         kunmap(page);
  59 }
  60
  61 static int udf_adinicb_readpage(struct file *file, struct page *page)
  62 {
  63         BUG_ON(!PageLocked(page));
  64         __udf_adinicb_readpage(page);
  65         unlock_page(page);
  66
  67         return 0;
  68 }
  69
  70 static int udf_adinicb_writepage(struct page *page,
  71                                  struct writeback_control *wbc)
  72 {
  73         struct inode *inode = page->mapping->host;
  74         char *kaddr;
  75         struct udf_inode_info *iinfo = UDF_I(inode);
  76
  77         BUG_ON(!PageLocked(page));
  78
  79         kaddr = kmap(page);
  80         memcpy(iinfo->i_ext.i_data + iinfo->i_lenEAttr, kaddr, inode->i_size);
  81         mark_inode_dirty(inode);
  82         SetPageUptodate(page);
  83         kunmap(page);
  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_CACHE_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) && len != PAGE_CACHE_SIZE)
 104                 __udf_adinicb_readpage(page);
 105         return 0;
 106 }
 107
 108 static int udf_adinicb_write_end(struct file *file,
 109                         struct address_space *mapping,
 110                         loff_t pos, unsigned len, unsigned copied,
 111                         struct page *page, void *fsdata)
 112 {
 113         struct inode *inode = mapping->host;
 114         unsigned offset = pos & (PAGE_CACHE_SIZE - 1);
 115         char *kaddr;
 116         struct udf_inode_info *iinfo = UDF_I(inode);
 117
 118         kaddr = kmap_atomic(page, KM_USER0);
 119         memcpy(iinfo->i_ext.i_data + iinfo->i_lenEAttr + offset,
 120                 kaddr + offset, copied);
 121         kunmap_atomic(kaddr, KM_USER0);
 122
 123         return simple_write_end(file, mapping, pos, len, copied, page, fsdata);
 124 }
 125
 126 const struct address_space_operations udf_adinicb_aops = {
 127         .readpage       = udf_adinicb_readpage,
 128         .writepage      = udf_adinicb_writepage,
 129         .write_begin    = udf_adinicb_write_begin,
 130         .write_end      = udf_adinicb_write_end,
 131 };
 132
 133 static ssize_t udf_file_aio_write(struct kiocb *iocb, const struct iovec *iov,
 134                                   unsigned long nr_segs, loff_t ppos)
 135 {
 136         ssize_t retval;
 137         struct file *file = iocb->ki_filp;
 138         struct inode *inode = file->f_path.dentry->d_inode;
 139         int err, pos;
 140         size_t count = iocb->ki_left;
 141         struct udf_inode_info *iinfo = UDF_I(inode);
 142
 143         down_write(&iinfo->i_data_sem);
 144         if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_IN_ICB) {
 145                 if (file->f_flags & O_APPEND)
 146                         pos = inode->i_size;
 147                 else
 148                         pos = ppos;
 149
 150                 if (inode->i_sb->s_blocksize <
 151                                 (udf_file_entry_alloc_offset(inode) +
 152                                                 pos + count)) {
 153                         err = udf_expand_file_adinicb(inode);
 154                         if (err) {
 155                                 udf_debug("udf_expand_adinicb: err=%d\n", err);
 156                                 return err;
 157                         }
 158                 } else {
 159                         if (pos + count > inode->i_size)
 160                                 iinfo->i_lenAlloc = pos + count;
 161                         else
 162                                 iinfo->i_lenAlloc = inode->i_size;
 163                         up_write(&iinfo->i_data_sem);
 164                 }
 165         } else
 166                 up_write(&iinfo->i_data_sem);
 167
 168         retval = generic_file_aio_write(iocb, iov, nr_segs, ppos);
 169         if (retval > 0)
 170                 mark_inode_dirty(inode);
 171
 172         return retval;
 173 }
 174
 175 long udf_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 176 {
 177         struct inode *inode = filp->f_dentry->d_inode;
 178         long old_block, new_block;
 179         int result = -EINVAL;
 180
 181         if (inode_permission(inode, MAY_READ) != 0) {
 182                 udf_debug("no permission to access inode %lu\n", inode->i_ino);
 183                 result = -EPERM;
 184                 goto out;
 185         }
 186
 187         if (!arg) {
 188                 udf_debug("invalid argument to udf_ioctl\n");
 189                 result = -EINVAL;
 190                 goto out;
 191         }
 192
 193         switch (cmd) {
 194         case UDF_GETVOLIDENT:
 195                 if (copy_to_user((char __user *)arg,
 196                                  UDF_SB(inode->i_sb)->s_volume_ident, 32))
 197                         result = -EFAULT;
 198                 else
 199                         result = 0;
 200                 goto out;
 201         case UDF_RELOCATE_BLOCKS:
 202                 if (!capable(CAP_SYS_ADMIN)) {
 203                         result = -EACCES;
 204                         goto out;
 205                 }
 206                 if (get_user(old_block, (long __user *)arg)) {
 207                         result = -EFAULT;
 208                         goto out;
 209                 }
 210                 result = udf_relocate_blocks(inode->i_sb,
 211                                                 old_block, &new_block);
 212                 if (result == 0)
 213                         result = put_user(new_block, (long __user *)arg);
 214                 goto out;
 215         case UDF_GETEASIZE:
 216                 result = put_user(UDF_I(inode)->i_lenEAttr, (int __user *)arg);
 217                 goto out;
 218         case UDF_GETEABLOCK:
 219                 result = copy_to_user((char __user *)arg,
 220                                       UDF_I(inode)->i_ext.i_data,
 221                                       UDF_I(inode)->i_lenEAttr) ? -EFAULT : 0;
 222                 goto out;
 223         }
 224
 225 out:
 226         return result;
 227 }
 228
 229 static int udf_release_file(struct inode *inode, struct file *filp)
 230 {
 231         if (filp->f_mode & FMODE_WRITE) {
 232                 down_write(&UDF_I(inode)->i_data_sem);
 233                 udf_discard_prealloc(inode);
 234                 udf_truncate_tail_extent(inode);
 235                 up_write(&UDF_I(inode)->i_data_sem);
 236         }
 237         return 0;
 238 }
 239
 240 const struct file_operations udf_file_operations = {
 241         .read                   = do_sync_read,
 242         .aio_read               = generic_file_aio_read,
 243         .unlocked_ioctl         = udf_ioctl,
 244         .open                   = generic_file_open,
 245         .mmap                   = generic_file_mmap,
 246         .write                  = do_sync_write,
 247         .aio_write              = udf_file_aio_write,
 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 = dentry->d_inode;
 257         int error;
 258
 259         error = setattr_prepare(dentry, attr);
 260         if (error)
 261                 return error;
 262
 263         if ((attr->ia_valid & ATTR_SIZE) &&
 264             attr->ia_size != i_size_read(inode)) {
 265                 error = udf_setsize(inode, attr->ia_size);
 266                 if (error)
 267                         return error;
 268         }
 269
 270         setattr_copy(inode, attr);
 271         mark_inode_dirty(inode);
 272         return 0;
 273 }
 274
 275 const struct inode_operations udf_file_inode_operations = {
 276         .setattr                = udf_setattr,
 277 };