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 vm_fault_t udf_page_mkwrite(struct vm_fault *vmf)
  42 {
  43         struct vm_area_struct *vma = vmf->vma;
  44         struct inode *inode = file_inode(vma->vm_file);
  45         struct address_space *mapping = inode->i_mapping;
  46         struct page *page = vmf->page;
  47         loff_t size;
  48         unsigned int end;
  49         vm_fault_t ret = VM_FAULT_LOCKED;
  50         int err;
  51
  52         sb_start_pagefault(inode->i_sb);
  53         file_update_time(vma->vm_file);
  54         filemap_invalidate_lock_shared(mapping);
  55         lock_page(page);
  56         size = i_size_read(inode);
  57         if (page->mapping != inode->i_mapping || page_offset(page) >= size) {
  58                 unlock_page(page);
  59                 ret = VM_FAULT_NOPAGE;
  60                 goto out_unlock;
  61         }
  62         /* Space is already allocated for in-ICB file */
  63         if (UDF_I(inode)->i_alloc_type == ICBTAG_FLAG_AD_IN_ICB)
  64                 goto out_dirty;
  65         if (page->index == size >> PAGE_SHIFT)
  66                 end = size & ~PAGE_MASK;
  67         else
  68                 end = PAGE_SIZE;
  69         err = __block_write_begin(page, 0, end, udf_get_block);
  70         if (!err)
  71                 err = block_commit_write(page, 0, end);
  72         if (err < 0) {
  73                 unlock_page(page);
  74                 ret = block_page_mkwrite_return(err);
  75                 goto out_unlock;
  76         }
  77 out_dirty:
  78         set_page_dirty(page);
  79         wait_for_stable_page(page);
  80 out_unlock:
  81         filemap_invalidate_unlock_shared(mapping);
  82         sb_end_pagefault(inode->i_sb);
  83         return ret;
  84 }
  85
  86 static const struct vm_operations_struct udf_file_vm_ops = {
  87         .fault          = filemap_fault,
  88         .map_pages      = filemap_map_pages,
  89         .page_mkwrite   = udf_page_mkwrite,
  90 };
  91
  92 static ssize_t udf_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
  93 {
  94         ssize_t retval;
  95         struct file *file = iocb->ki_filp;
  96         struct inode *inode = file_inode(file);
  97         struct udf_inode_info *iinfo = UDF_I(inode);
  98
  99         inode_lock(inode);
 100
 101         retval = generic_write_checks(iocb, from);
 102         if (retval <= 0)
 103                 goto out;
 104
 105         if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_IN_ICB &&
 106             inode->i_sb->s_blocksize < (udf_file_entry_alloc_offset(inode) +
 107                                  iocb->ki_pos + iov_iter_count(from))) {
 108                 filemap_invalidate_lock(inode->i_mapping);
 109                 retval = udf_expand_file_adinicb(inode);
 110                 filemap_invalidate_unlock(inode->i_mapping);
 111                 if (retval)
 112                         goto out;
 113         }
 114
 115         retval = __generic_file_write_iter(iocb, from);
 116 out:
 117         if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_IN_ICB && retval > 0) {
 118                 down_write(&iinfo->i_data_sem);
 119                 iinfo->i_lenAlloc = inode->i_size;
 120                 up_write(&iinfo->i_data_sem);
 121         }
 122         inode_unlock(inode);
 123
 124         if (retval > 0) {
 125                 mark_inode_dirty(inode);
 126                 retval = generic_write_sync(iocb, retval);
 127         }
 128
 129         return retval;
 130 }
 131
 132 long udf_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 133 {
 134         struct inode *inode = file_inode(filp);
 135         long old_block, new_block;
 136         int result;
 137
 138         if (file_permission(filp, MAY_READ) != 0) {
 139                 udf_debug("no permission to access inode %lu\n", inode->i_ino);
 140                 return -EPERM;
 141         }
 142
 143         if (!arg && ((cmd == UDF_GETVOLIDENT) || (cmd == UDF_GETEASIZE) ||
 144                      (cmd == UDF_RELOCATE_BLOCKS) || (cmd == UDF_GETEABLOCK))) {
 145                 udf_debug("invalid argument to udf_ioctl\n");
 146                 return -EINVAL;
 147         }
 148
 149         switch (cmd) {
 150         case UDF_GETVOLIDENT:
 151                 if (copy_to_user((char __user *)arg,
 152                                  UDF_SB(inode->i_sb)->s_volume_ident, 32))
 153                         return -EFAULT;
 154                 return 0;
 155         case UDF_RELOCATE_BLOCKS:
 156                 if (!capable(CAP_SYS_ADMIN))
 157                         return -EPERM;
 158                 if (get_user(old_block, (long __user *)arg))
 159                         return -EFAULT;
 160                 result = udf_relocate_blocks(inode->i_sb,
 161                                                 old_block, &new_block);
 162                 if (result == 0)
 163                         result = put_user(new_block, (long __user *)arg);
 164                 return result;
 165         case UDF_GETEASIZE:
 166                 return put_user(UDF_I(inode)->i_lenEAttr, (int __user *)arg);
 167         case UDF_GETEABLOCK:
 168                 return copy_to_user((char __user *)arg,
 169                                     UDF_I(inode)->i_data,
 170                                     UDF_I(inode)->i_lenEAttr) ? -EFAULT : 0;
 171         default:
 172                 return -ENOIOCTLCMD;
 173         }
 174
 175         return 0;
 176 }
 177
 178 static int udf_release_file(struct inode *inode, struct file *filp)
 179 {
 180         if (filp->f_mode & FMODE_WRITE &&
 181             atomic_read(&inode->i_writecount) == 1) {
 182                 /*
 183                  * Grab i_mutex to avoid races with writes changing i_size
 184                  * while we are running.
 185                  */
 186                 inode_lock(inode);
 187                 down_write(&UDF_I(inode)->i_data_sem);
 188                 udf_discard_prealloc(inode);
 189                 udf_truncate_tail_extent(inode);
 190                 up_write(&UDF_I(inode)->i_data_sem);
 191                 inode_unlock(inode);
 192         }
 193         return 0;
 194 }
 195
 196 static int udf_file_mmap(struct file *file, struct vm_area_struct *vma)
 197 {
 198         file_accessed(file);
 199         vma->vm_ops = &udf_file_vm_ops;
 200
 201         return 0;
 202 }
 203
 204 const struct file_operations udf_file_operations = {
 205         .read_iter              = generic_file_read_iter,
 206         .unlocked_ioctl         = udf_ioctl,
 207         .open                   = generic_file_open,
 208         .mmap                   = udf_file_mmap,
 209         .write_iter             = udf_file_write_iter,
 210         .release                = udf_release_file,
 211         .fsync                  = generic_file_fsync,
 212         .splice_read            = generic_file_splice_read,
 213         .splice_write           = iter_file_splice_write,
 214         .llseek                 = generic_file_llseek,
 215 };
 216
 217 static int udf_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
 218                        struct iattr *attr)
 219 {
 220         struct inode *inode = d_inode(dentry);
 221         struct super_block *sb = inode->i_sb;
 222         int error;
 223
 224         error = setattr_prepare(&nop_mnt_idmap, dentry, attr);
 225         if (error)
 226                 return error;
 227
 228         if ((attr->ia_valid & ATTR_UID) &&
 229             UDF_QUERY_FLAG(sb, UDF_FLAG_UID_SET) &&
 230             !uid_eq(attr->ia_uid, UDF_SB(sb)->s_uid))
 231                 return -EPERM;
 232         if ((attr->ia_valid & ATTR_GID) &&
 233             UDF_QUERY_FLAG(sb, UDF_FLAG_GID_SET) &&
 234             !gid_eq(attr->ia_gid, UDF_SB(sb)->s_gid))
 235                 return -EPERM;
 236
 237         if ((attr->ia_valid & ATTR_SIZE) &&
 238             attr->ia_size != i_size_read(inode)) {
 239                 error = udf_setsize(inode, attr->ia_size);
 240                 if (error)
 241                         return error;
 242         }
 243
 244         if (attr->ia_valid & ATTR_MODE)
 245                 udf_update_extra_perms(inode, attr->ia_mode);
 246
 247         setattr_copy(&nop_mnt_idmap, inode, attr);
 248         mark_inode_dirty(inode);
 249         return 0;
 250 }
 251
 252 const struct inode_operations udf_file_inode_operations = {
 253         .setattr                = udf_setattr,
 254 };