fs/udf/file.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * file.c
   4  *
   5  * PURPOSE
   6  *  File handling routines for the OSTA-UDF(tm) filesystem.
   7  *
   8  * COPYRIGHT
   9  *  (C) 1998-1999 Dave Boynton
  10  *  (C) 1998-2004 Ben Fennema
  11  *  (C) 1999-2000 Stelias Computing Inc
  12  *
  13  * HISTORY
  14  *
  15  *  10/02/98 dgb  Attempt to integrate into udf.o
  16  *  10/07/98      Switched to using generic_readpage, etc., like isofs
  17  *                And it works!
  18  *  12/06/98 blf  Added udf_file_read. uses generic_file_read for all cases but
  19  *                ICBTAG_FLAG_AD_IN_ICB.
  20  *  04/06/99      64 bit file handling on 32 bit systems taken from ext2 file.c
  21  *  05/12/99      Preliminary file write support
  22  */
  23
  24 #include "udfdecl.h"
  25 #include <linux/fs.h>
  26 #include <linux/uaccess.h>
  27 #include <linux/kernel.h>
  28 #include <linux/string.h> /* memset */
  29 #include <linux/capability.h>
  30 #include <linux/errno.h>
  31 #include <linux/pagemap.h>
  32 #include <linux/uio.h>
  33
  34 #include "udf_i.h"
  35 #include "udf_sb.h"
  36
  37 static vm_fault_t udf_page_mkwrite(struct vm_fault *vmf)
  38 {
  39         struct vm_area_struct *vma = vmf->vma;
  40         struct inode *inode = file_inode(vma->vm_file);
  41         struct address_space *mapping = inode->i_mapping;
  42         struct folio *folio = page_folio(vmf->page);
  43         loff_t size;
  44         unsigned int end;
  45         vm_fault_t ret = VM_FAULT_LOCKED;
  46         int err;
  47
  48         sb_start_pagefault(inode->i_sb);
  49         file_update_time(vma->vm_file);
  50         filemap_invalidate_lock_shared(mapping);
  51         folio_lock(folio);
  52         size = i_size_read(inode);
  53         if (folio->mapping != inode->i_mapping || folio_pos(folio) >= size) {
  54                 folio_unlock(folio);
  55                 ret = VM_FAULT_NOPAGE;
  56                 goto out_unlock;
  57         }
  58         /* Space is already allocated for in-ICB file */
  59         if (UDF_I(inode)->i_alloc_type == ICBTAG_FLAG_AD_IN_ICB)
  60                 goto out_dirty;
  61         if (folio->index == size >> PAGE_SHIFT)
  62                 end = size & ~PAGE_MASK;
  63         else
  64                 end = PAGE_SIZE;
  65         err = __block_write_begin(&folio->page, 0, end, udf_get_block);
  66         if (err) {
  67                 folio_unlock(folio);
  68                 ret = vmf_fs_error(err);
  69                 goto out_unlock;
  70         }
  71
  72         block_commit_write(&folio->page, 0, end);
  73 out_dirty:
  74         folio_mark_dirty(folio);
  75         folio_wait_stable(folio);
  76 out_unlock:
  77         filemap_invalidate_unlock_shared(mapping);
  78         sb_end_pagefault(inode->i_sb);
  79         return ret;
  80 }
  81
  82 static const struct vm_operations_struct udf_file_vm_ops = {
  83         .fault          = filemap_fault,
  84         .map_pages      = filemap_map_pages,
  85         .page_mkwrite   = udf_page_mkwrite,
  86 };
  87
  88 static ssize_t udf_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
  89 {
  90         ssize_t retval;
  91         struct file *file = iocb->ki_filp;
  92         struct inode *inode = file_inode(file);
  93         struct udf_inode_info *iinfo = UDF_I(inode);
  94
  95         inode_lock(inode);
  96
  97         retval = generic_write_checks(iocb, from);
  98         if (retval <= 0)
  99                 goto out;
 100
 101         if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_IN_ICB &&
 102             inode->i_sb->s_blocksize < (udf_file_entry_alloc_offset(inode) +
 103                                  iocb->ki_pos + iov_iter_count(from))) {
 104                 filemap_invalidate_lock(inode->i_mapping);
 105                 retval = udf_expand_file_adinicb(inode);
 106                 filemap_invalidate_unlock(inode->i_mapping);
 107                 if (retval)
 108                         goto out;
 109         }
 110
 111         retval = __generic_file_write_iter(iocb, from);
 112 out:
 113         if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_IN_ICB && retval > 0) {
 114                 down_write(&iinfo->i_data_sem);
 115                 iinfo->i_lenAlloc = inode->i_size;
 116                 up_write(&iinfo->i_data_sem);
 117         }
 118         inode_unlock(inode);
 119
 120         if (retval > 0) {
 121                 mark_inode_dirty(inode);
 122                 retval = generic_write_sync(iocb, retval);
 123         }
 124
 125         return retval;
 126 }
 127
 128 long udf_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 129 {
 130         struct inode *inode = file_inode(filp);
 131         long old_block, new_block;
 132         int result;
 133
 134         if (file_permission(filp, MAY_READ) != 0) {
 135                 udf_debug("no permission to access inode %lu\n", inode->i_ino);
 136                 return -EPERM;
 137         }
 138
 139         if (!arg && ((cmd == UDF_GETVOLIDENT) || (cmd == UDF_GETEASIZE) ||
 140                      (cmd == UDF_RELOCATE_BLOCKS) || (cmd == UDF_GETEABLOCK))) {
 141                 udf_debug("invalid argument to udf_ioctl\n");
 142                 return -EINVAL;
 143         }
 144
 145         switch (cmd) {
 146         case UDF_GETVOLIDENT:
 147                 if (copy_to_user((char __user *)arg,
 148                                  UDF_SB(inode->i_sb)->s_volume_ident, 32))
 149                         return -EFAULT;
 150                 return 0;
 151         case UDF_RELOCATE_BLOCKS:
 152                 if (!capable(CAP_SYS_ADMIN))
 153                         return -EPERM;
 154                 if (get_user(old_block, (long __user *)arg))
 155                         return -EFAULT;
 156                 result = udf_relocate_blocks(inode->i_sb,
 157                                                 old_block, &new_block);
 158                 if (result == 0)
 159                         result = put_user(new_block, (long __user *)arg);
 160                 return result;
 161         case UDF_GETEASIZE:
 162                 return put_user(UDF_I(inode)->i_lenEAttr, (int __user *)arg);
 163         case UDF_GETEABLOCK:
 164                 return copy_to_user((char __user *)arg,
 165                                     UDF_I(inode)->i_data,
 166                                     UDF_I(inode)->i_lenEAttr) ? -EFAULT : 0;
 167         default:
 168                 return -ENOIOCTLCMD;
 169         }
 170
 171         return 0;
 172 }
 173
 174 static int udf_release_file(struct inode *inode, struct file *filp)
 175 {
 176         if (filp->f_mode & FMODE_WRITE &&
 177             atomic_read(&inode->i_writecount) == 1) {
 178                 /*
 179                  * Grab i_mutex to avoid races with writes changing i_size
 180                  * while we are running.
 181                  */
 182                 inode_lock(inode);
 183                 down_write(&UDF_I(inode)->i_data_sem);
 184                 udf_discard_prealloc(inode);
 185                 udf_truncate_tail_extent(inode);
 186                 up_write(&UDF_I(inode)->i_data_sem);
 187                 inode_unlock(inode);
 188         }
 189         return 0;
 190 }
 191
 192 static int udf_file_mmap(struct file *file, struct vm_area_struct *vma)
 193 {
 194         file_accessed(file);
 195         vma->vm_ops = &udf_file_vm_ops;
 196
 197         return 0;
 198 }
 199
 200 const struct file_operations udf_file_operations = {
 201         .read_iter              = generic_file_read_iter,
 202         .unlocked_ioctl         = udf_ioctl,
 203         .open                   = generic_file_open,
 204         .mmap                   = udf_file_mmap,
 205         .write_iter             = udf_file_write_iter,
 206         .release                = udf_release_file,
 207         .fsync                  = generic_file_fsync,
 208         .splice_read            = filemap_splice_read,
 209         .splice_write           = iter_file_splice_write,
 210         .llseek                 = generic_file_llseek,
 211 };
 212
 213 static int udf_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
 214                        struct iattr *attr)
 215 {
 216         struct inode *inode = d_inode(dentry);
 217         struct super_block *sb = inode->i_sb;
 218         int error;
 219
 220         error = setattr_prepare(&nop_mnt_idmap, dentry, attr);
 221         if (error)
 222                 return error;
 223
 224         if ((attr->ia_valid & ATTR_UID) &&
 225             UDF_QUERY_FLAG(sb, UDF_FLAG_UID_SET) &&
 226             !uid_eq(attr->ia_uid, UDF_SB(sb)->s_uid))
 227                 return -EPERM;
 228         if ((attr->ia_valid & ATTR_GID) &&
 229             UDF_QUERY_FLAG(sb, UDF_FLAG_GID_SET) &&
 230             !gid_eq(attr->ia_gid, UDF_SB(sb)->s_gid))
 231                 return -EPERM;
 232
 233         if ((attr->ia_valid & ATTR_SIZE) &&
 234             attr->ia_size != i_size_read(inode)) {
 235                 error = udf_setsize(inode, attr->ia_size);
 236                 if (error)
 237                         return error;
 238         }
 239
 240         if (attr->ia_valid & ATTR_MODE)
 241                 udf_update_extra_perms(inode, attr->ia_mode);
 242
 243         setattr_copy(&nop_mnt_idmap, inode, attr);
 244         mark_inode_dirty(inode);
 245         return 0;
 246 }
 247
 248 const struct inode_operations udf_file_inode_operations = {
 249         .setattr                = udf_setattr,
 250 };