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 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_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 60 static int udf_adinicb_read_folio(struct file *file, struct folio *folio) 61 { 62 BUG_ON(!folio_test_locked(folio)); 63 __udf_adinicb_readpage(&folio->page); 64 folio_unlock(folio); 65 66 return 0; 67 } 68 69 static 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_data + iinfo->i_lenEAttr, kaddr, i_size_read(inode)); 80 SetPageUptodate(page); 81 kunmap_atomic(kaddr); 82 mark_inode_dirty(inode); 83 unlock_page(page); 84 85 return 0; 86 } 87 88 static int udf_adinicb_write_begin(struct file *file, 89 struct address_space *mapping, loff_t pos, 90 unsigned len, struct page **pagep, 91 void **fsdata) 92 { 93 struct page *page; 94 95 if (WARN_ON_ONCE(pos >= PAGE_SIZE)) 96 return -EIO; 97 page = grab_cache_page_write_begin(mapping, 0); 98 if (!page) 99 return -ENOMEM; 100 *pagep = page; 101 102 if (!PageUptodate(page)) 103 __udf_adinicb_readpage(page); 104 return 0; 105 } 106 107 static ssize_t udf_adinicb_direct_IO(struct kiocb *iocb, struct iov_iter *iter) 108 { 109 /* Fallback to buffered I/O. */ 110 return 0; 111 } 112 113 static int udf_adinicb_write_end(struct file *file, struct address_space *mapping, 114 loff_t pos, unsigned len, unsigned copied, 115 struct page *page, void *fsdata) 116 { 117 struct inode *inode = page->mapping->host; 118 loff_t last_pos = pos + copied; 119 if (last_pos > inode->i_size) 120 i_size_write(inode, last_pos); 121 set_page_dirty(page); 122 unlock_page(page); 123 put_page(page); 124 return copied; 125 } 126 127 const struct address_space_operations udf_adinicb_aops = { 128 .dirty_folio = block_dirty_folio, 129 .invalidate_folio = block_invalidate_folio, 130 .read_folio = udf_adinicb_read_folio, 131 .writepage = udf_adinicb_writepage, 132 .write_begin = udf_adinicb_write_begin, 133 .write_end = udf_adinicb_write_end, 134 .direct_IO = udf_adinicb_direct_IO, 135 }; 136 137 static ssize_t udf_file_write_iter(struct kiocb *iocb, struct iov_iter *from) 138 { 139 ssize_t retval; 140 struct file *file = iocb->ki_filp; 141 struct inode *inode = file_inode(file); 142 struct udf_inode_info *iinfo = UDF_I(inode); 143 int err; 144 145 inode_lock(inode); 146 147 retval = generic_write_checks(iocb, from); 148 if (retval <= 0) 149 goto out; 150 151 down_write(&iinfo->i_data_sem); 152 if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_IN_ICB) { 153 loff_t end = iocb->ki_pos + iov_iter_count(from); 154 155 if (inode->i_sb->s_blocksize < 156 (udf_file_entry_alloc_offset(inode) + end)) { 157 err = udf_expand_file_adinicb(inode); 158 if (err) { 159 inode_unlock(inode); 160 udf_debug("udf_expand_adinicb: err=%d\n", err); 161 return err; 162 } 163 } else { 164 iinfo->i_lenAlloc = max(end, inode->i_size); 165 up_write(&iinfo->i_data_sem); 166 } 167 } else 168 up_write(&iinfo->i_data_sem); 169 170 retval = __generic_file_write_iter(iocb, from); 171 out: 172 inode_unlock(inode); 173 174 if (retval > 0) { 175 mark_inode_dirty(inode); 176 retval = generic_write_sync(iocb, retval); 177 } 178 179 return retval; 180 } 181 182 long udf_ioctl(struct file *filp, unsigned int cmd, unsigned long arg) 183 { 184 struct inode *inode = file_inode(filp); 185 long old_block, new_block; 186 int result; 187 188 if (file_permission(filp, MAY_READ) != 0) { 189 udf_debug("no permission to access inode %lu\n", inode->i_ino); 190 return -EPERM; 191 } 192 193 if (!arg && ((cmd == UDF_GETVOLIDENT) || (cmd == UDF_GETEASIZE) || 194 (cmd == UDF_RELOCATE_BLOCKS) || (cmd == UDF_GETEABLOCK))) { 195 udf_debug("invalid argument to udf_ioctl\n"); 196 return -EINVAL; 197 } 198 199 switch (cmd) { 200 case UDF_GETVOLIDENT: 201 if (copy_to_user((char __user *)arg, 202 UDF_SB(inode->i_sb)->s_volume_ident, 32)) 203 return -EFAULT; 204 return 0; 205 case UDF_RELOCATE_BLOCKS: 206 if (!capable(CAP_SYS_ADMIN)) 207 return -EPERM; 208 if (get_user(old_block, (long __user *)arg)) 209 return -EFAULT; 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 return result; 215 case UDF_GETEASIZE: 216 return put_user(UDF_I(inode)->i_lenEAttr, (int __user *)arg); 217 case UDF_GETEABLOCK: 218 return copy_to_user((char __user *)arg, 219 UDF_I(inode)->i_data, 220 UDF_I(inode)->i_lenEAttr) ? -EFAULT : 0; 221 default: 222 return -ENOIOCTLCMD; 223 } 224 225 return 0; 226 } 227 228 static int udf_release_file(struct inode *inode, struct file *filp) 229 { 230 if (filp->f_mode & FMODE_WRITE && 231 atomic_read(&inode->i_writecount) == 1) { 232 /* 233 * Grab i_mutex to avoid races with writes changing i_size 234 * while we are running. 235 */ 236 inode_lock(inode); 237 down_write(&UDF_I(inode)->i_data_sem); 238 udf_discard_prealloc(inode); 239 udf_truncate_tail_extent(inode); 240 up_write(&UDF_I(inode)->i_data_sem); 241 inode_unlock(inode); 242 } 243 return 0; 244 } 245 246 const struct file_operations udf_file_operations = { 247 .read_iter = generic_file_read_iter, 248 .unlocked_ioctl = udf_ioctl, 249 .open = generic_file_open, 250 .mmap = generic_file_mmap, 251 .write_iter = udf_file_write_iter, 252 .release = udf_release_file, 253 .fsync = generic_file_fsync, 254 .splice_read = generic_file_splice_read, 255 .llseek = generic_file_llseek, 256 }; 257 258 static int udf_setattr(struct user_namespace *mnt_userns, struct dentry *dentry, 259 struct iattr *attr) 260 { 261 struct inode *inode = d_inode(dentry); 262 struct super_block *sb = inode->i_sb; 263 int error; 264 265 error = setattr_prepare(&init_user_ns, dentry, attr); 266 if (error) 267 return error; 268 269 if ((attr->ia_valid & ATTR_UID) && 270 UDF_QUERY_FLAG(sb, UDF_FLAG_UID_SET) && 271 !uid_eq(attr->ia_uid, UDF_SB(sb)->s_uid)) 272 return -EPERM; 273 if ((attr->ia_valid & ATTR_GID) && 274 UDF_QUERY_FLAG(sb, UDF_FLAG_GID_SET) && 275 !gid_eq(attr->ia_gid, UDF_SB(sb)->s_gid)) 276 return -EPERM; 277 278 if ((attr->ia_valid & ATTR_SIZE) && 279 attr->ia_size != i_size_read(inode)) { 280 error = udf_setsize(inode, attr->ia_size); 281 if (error) 282 return error; 283 } 284 285 if (attr->ia_valid & ATTR_MODE) 286 udf_update_extra_perms(inode, attr->ia_mode); 287 288 setattr_copy(&init_user_ns, inode, attr); 289 mark_inode_dirty(inode); 290 return 0; 291 } 292 293 const struct inode_operations udf_file_inode_operations = { 294 .setattr = udf_setattr, 295 }; 296