linux/fs/udf/file.c
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   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
  41static 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
  60static 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
  69static 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
  89static 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
 108static 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
 114static 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
 128const 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
 136static 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);
 170out:
 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
 181long 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
 227static 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
 245const 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
 257static int udf_setattr(struct dentry *dentry, struct iattr *attr)
 258{
 259        struct inode *inode = d_inode(dentry);
 260        int error;
 261
 262        error = setattr_prepare(dentry, attr);
 263        if (error)
 264                return error;
 265
 266        if ((attr->ia_valid & ATTR_SIZE) &&
 267            attr->ia_size != i_size_read(inode)) {
 268                error = udf_setsize(inode, attr->ia_size);
 269                if (error)
 270                        return error;
 271        }
 272
 273        setattr_copy(inode, attr);
 274        mark_inode_dirty(inode);
 275        return 0;
 276}
 277
 278const struct inode_operations udf_file_inode_operations = {
 279        .setattr                = udf_setattr,
 280};
 281