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_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 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, unsigned flags, 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, flags); 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 .readpage = udf_adinicb_readpage, 129 .writepage = udf_adinicb_writepage, 130 .write_begin = udf_adinicb_write_begin, 131 .write_end = udf_adinicb_write_end, 132 .direct_IO = udf_adinicb_direct_IO, 133 }; 134 135 static ssize_t udf_file_write_iter(struct kiocb *iocb, struct iov_iter *from) 136 { 137 ssize_t retval; 138 struct file *file = iocb->ki_filp; 139 struct inode *inode = file_inode(file); 140 struct udf_inode_info *iinfo = UDF_I(inode); 141 int err; 142 143 inode_lock(inode); 144 145 retval = generic_write_checks(iocb, from); 146 if (retval <= 0) 147 goto out; 148 149 down_write(&iinfo->i_data_sem); 150 if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_IN_ICB) { 151 loff_t end = iocb->ki_pos + iov_iter_count(from); 152 153 if (inode->i_sb->s_blocksize < 154 (udf_file_entry_alloc_offset(inode) + end)) { 155 err = udf_expand_file_adinicb(inode); 156 if (err) { 157 inode_unlock(inode); 158 udf_debug("udf_expand_adinicb: err=%d\n", err); 159 return err; 160 } 161 } else { 162 iinfo->i_lenAlloc = max(end, inode->i_size); 163 up_write(&iinfo->i_data_sem); 164 } 165 } else 166 up_write(&iinfo->i_data_sem); 167 168 retval = __generic_file_write_iter(iocb, from); 169 out: 170 inode_unlock(inode); 171 172 if (retval > 0) { 173 mark_inode_dirty(inode); 174 retval = generic_write_sync(iocb, retval); 175 } 176 177 return retval; 178 } 179 180 long udf_ioctl(struct file *filp, unsigned int cmd, unsigned long arg) 181 { 182 struct inode *inode = file_inode(filp); 183 long old_block, new_block; 184 int result; 185 186 if (file_permission(filp, MAY_READ) != 0) { 187 udf_debug("no permission to access inode %lu\n", inode->i_ino); 188 return -EPERM; 189 } 190 191 if (!arg && ((cmd == UDF_GETVOLIDENT) || (cmd == UDF_GETEASIZE) || 192 (cmd == UDF_RELOCATE_BLOCKS) || (cmd == UDF_GETEABLOCK))) { 193 udf_debug("invalid argument to udf_ioctl\n"); 194 return -EINVAL; 195 } 196 197 switch (cmd) { 198 case UDF_GETVOLIDENT: 199 if (copy_to_user((char __user *)arg, 200 UDF_SB(inode->i_sb)->s_volume_ident, 32)) 201 return -EFAULT; 202 return 0; 203 case UDF_RELOCATE_BLOCKS: 204 if (!capable(CAP_SYS_ADMIN)) 205 return -EPERM; 206 if (get_user(old_block, (long __user *)arg)) 207 return -EFAULT; 208 result = udf_relocate_blocks(inode->i_sb, 209 old_block, &new_block); 210 if (result == 0) 211 result = put_user(new_block, (long __user *)arg); 212 return result; 213 case UDF_GETEASIZE: 214 return put_user(UDF_I(inode)->i_lenEAttr, (int __user *)arg); 215 case UDF_GETEABLOCK: 216 return copy_to_user((char __user *)arg, 217 UDF_I(inode)->i_data, 218 UDF_I(inode)->i_lenEAttr) ? -EFAULT : 0; 219 default: 220 return -ENOIOCTLCMD; 221 } 222 223 return 0; 224 } 225 226 static int udf_release_file(struct inode *inode, struct file *filp) 227 { 228 if (filp->f_mode & FMODE_WRITE && 229 atomic_read(&inode->i_writecount) == 1) { 230 /* 231 * Grab i_mutex to avoid races with writes changing i_size 232 * while we are running. 233 */ 234 inode_lock(inode); 235 down_write(&UDF_I(inode)->i_data_sem); 236 udf_discard_prealloc(inode); 237 udf_truncate_tail_extent(inode); 238 up_write(&UDF_I(inode)->i_data_sem); 239 inode_unlock(inode); 240 } 241 return 0; 242 } 243 244 const struct file_operations udf_file_operations = { 245 .read_iter = generic_file_read_iter, 246 .unlocked_ioctl = udf_ioctl, 247 .open = generic_file_open, 248 .mmap = generic_file_mmap, 249 .write_iter = udf_file_write_iter, 250 .release = udf_release_file, 251 .fsync = generic_file_fsync, 252 .splice_read = generic_file_splice_read, 253 .llseek = generic_file_llseek, 254 }; 255 256 static int udf_setattr(struct user_namespace *mnt_userns, struct dentry *dentry, 257 struct iattr *attr) 258 { 259 struct inode *inode = d_inode(dentry); 260 struct super_block *sb = inode->i_sb; 261 int error; 262 263 error = setattr_prepare(&init_user_ns, dentry, attr); 264 if (error) 265 return error; 266 267 if ((attr->ia_valid & ATTR_UID) && 268 UDF_QUERY_FLAG(sb, UDF_FLAG_UID_SET) && 269 !uid_eq(attr->ia_uid, UDF_SB(sb)->s_uid)) 270 return -EPERM; 271 if ((attr->ia_valid & ATTR_GID) && 272 UDF_QUERY_FLAG(sb, UDF_FLAG_GID_SET) && 273 !gid_eq(attr->ia_gid, UDF_SB(sb)->s_gid)) 274 return -EPERM; 275 276 if ((attr->ia_valid & ATTR_SIZE) && 277 attr->ia_size != i_size_read(inode)) { 278 error = udf_setsize(inode, attr->ia_size); 279 if (error) 280 return error; 281 } 282 283 if (attr->ia_valid & ATTR_MODE) 284 udf_update_extra_perms(inode, attr->ia_mode); 285 286 setattr_copy(&init_user_ns, inode, attr); 287 mark_inode_dirty(inode); 288 return 0; 289 } 290 291 const struct inode_operations udf_file_inode_operations = { 292 .setattr = udf_setattr, 293 }; 294