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
  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
  55static 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
  64static 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
  83static 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))
  98                __udf_adinicb_readpage(page);
  99        return 0;
 100}
 101
 102static 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
 108static int udf_adinicb_write_end(struct file *file, struct address_space *mapping,
 109                                 loff_t pos, unsigned len, unsigned copied,
 110                                 struct page *page, void *fsdata)
 111{
 112        struct inode *inode = page->mapping->host;
 113        loff_t last_pos = pos + copied;
 114        if (last_pos > inode->i_size)
 115                i_size_write(inode, last_pos);
 116        set_page_dirty(page);
 117        unlock_page(page);
 118        put_page(page);
 119        return copied;
 120}
 121
 122const struct address_space_operations udf_adinicb_aops = {
 123        .readpage       = udf_adinicb_readpage,
 124        .writepage      = udf_adinicb_writepage,
 125        .write_begin    = udf_adinicb_write_begin,
 126        .write_end      = udf_adinicb_write_end,
 127        .direct_IO      = udf_adinicb_direct_IO,
 128};
 129
 130static ssize_t udf_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
 131{
 132        ssize_t retval;
 133        struct file *file = iocb->ki_filp;
 134        struct inode *inode = file_inode(file);
 135        struct udf_inode_info *iinfo = UDF_I(inode);
 136        int err;
 137
 138        inode_lock(inode);
 139
 140        retval = generic_write_checks(iocb, from);
 141        if (retval <= 0)
 142                goto out;
 143
 144        down_write(&iinfo->i_data_sem);
 145        if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_IN_ICB) {
 146                loff_t end = iocb->ki_pos + iov_iter_count(from);
 147
 148                if (inode->i_sb->s_blocksize <
 149                                (udf_file_entry_alloc_offset(inode) + end)) {
 150                        err = udf_expand_file_adinicb(inode);
 151                        if (err) {
 152                                inode_unlock(inode);
 153                                udf_debug("udf_expand_adinicb: err=%d\n", err);
 154                                return err;
 155                        }
 156                } else {
 157                        iinfo->i_lenAlloc = max(end, inode->i_size);
 158                        up_write(&iinfo->i_data_sem);
 159                }
 160        } else
 161                up_write(&iinfo->i_data_sem);
 162
 163        retval = __generic_file_write_iter(iocb, from);
 164out:
 165        inode_unlock(inode);
 166
 167        if (retval > 0) {
 168                mark_inode_dirty(inode);
 169                retval = generic_write_sync(iocb, retval);
 170        }
 171
 172        return retval;
 173}
 174
 175long udf_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 176{
 177        struct inode *inode = file_inode(filp);
 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 = -EPERM;
 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
 225out:
 226        return result;
 227}
 228
 229static int udf_release_file(struct inode *inode, struct file *filp)
 230{
 231        if (filp->f_mode & FMODE_WRITE &&
 232            atomic_read(&inode->i_writecount) == 1) {
 233                /*
 234                 * Grab i_mutex to avoid races with writes changing i_size
 235                 * while we are running.
 236                 */
 237                inode_lock(inode);
 238                down_write(&UDF_I(inode)->i_data_sem);
 239                udf_discard_prealloc(inode);
 240                udf_truncate_tail_extent(inode);
 241                up_write(&UDF_I(inode)->i_data_sem);
 242                inode_unlock(inode);
 243        }
 244        return 0;
 245}
 246
 247const struct file_operations udf_file_operations = {
 248        .read_iter              = generic_file_read_iter,
 249        .unlocked_ioctl         = udf_ioctl,
 250        .open                   = generic_file_open,
 251        .mmap                   = generic_file_mmap,
 252        .write_iter             = udf_file_write_iter,
 253        .release                = udf_release_file,
 254        .fsync                  = generic_file_fsync,
 255        .splice_read            = generic_file_splice_read,
 256        .llseek                 = generic_file_llseek,
 257};
 258
 259static int udf_setattr(struct dentry *dentry, struct iattr *attr)
 260{
 261        struct inode *inode = d_inode(dentry);
 262        int error;
 263
 264        error = setattr_prepare(dentry, attr);
 265        if (error)
 266                return error;
 267
 268        if ((attr->ia_valid & ATTR_SIZE) &&
 269            attr->ia_size != i_size_read(inode)) {
 270                error = udf_setsize(inode, attr->ia_size);
 271                if (error)
 272                        return error;
 273        }
 274
 275        setattr_copy(inode, attr);
 276        mark_inode_dirty(inode);
 277        return 0;
 278}
 279
 280const struct inode_operations udf_file_inode_operations = {
 281        .setattr                = udf_setattr,
 282};
 283