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