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_ext.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_ext.i_data + iinfo->i_lenEAttr, kaddr, 80 i_size_read(inode)); 81 SetPageUptodate(page); 82 kunmap_atomic(kaddr); 83 mark_inode_dirty(inode); 84 unlock_page(page); 85 86 return 0; 87 } 88 89 static int udf_adinicb_write_begin(struct file *file, 90 struct address_space *mapping, loff_t pos, 91 unsigned len, unsigned flags, struct page **pagep, 92 void **fsdata) 93 { 94 struct page *page; 95 96 if (WARN_ON_ONCE(pos >= PAGE_SIZE)) 97 return -EIO; 98 page = grab_cache_page_write_begin(mapping, 0, flags); 99 if (!page) 100 return -ENOMEM; 101 *pagep = page; 102 103 if (!PageUptodate(page)) 104 __udf_adinicb_readpage(page); 105 return 0; 106 } 107 108 static ssize_t udf_adinicb_direct_IO(struct kiocb *iocb, struct iov_iter *iter) 109 { 110 /* Fallback to buffered I/O. */ 111 return 0; 112 } 113 114 static int udf_adinicb_write_end(struct file *file, struct address_space *mapping, 115 loff_t pos, unsigned len, unsigned copied, 116 struct page *page, void *fsdata) 117 { 118 struct inode *inode = page->mapping->host; 119 loff_t last_pos = pos + copied; 120 if (last_pos > inode->i_size) 121 i_size_write(inode, last_pos); 122 set_page_dirty(page); 123 unlock_page(page); 124 put_page(page); 125 return copied; 126 } 127 128 const struct address_space_operations udf_adinicb_aops = { 129 .readpage = udf_adinicb_readpage, 130 .writepage = udf_adinicb_writepage, 131 .write_begin = udf_adinicb_write_begin, 132 .write_end = udf_adinicb_write_end, 133 .direct_IO = udf_adinicb_direct_IO, 134 }; 135 136 static ssize_t udf_file_write_iter(struct kiocb *iocb, struct iov_iter *from) 137 { 138 ssize_t retval; 139 struct file *file = iocb->ki_filp; 140 struct inode *inode = file_inode(file); 141 struct udf_inode_info *iinfo = UDF_I(inode); 142 int err; 143 144 inode_lock(inode); 145 146 retval = generic_write_checks(iocb, from); 147 if (retval <= 0) 148 goto out; 149 150 down_write(&iinfo->i_data_sem); 151 if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_IN_ICB) { 152 loff_t end = iocb->ki_pos + iov_iter_count(from); 153 154 if (inode->i_sb->s_blocksize < 155 (udf_file_entry_alloc_offset(inode) + end)) { 156 err = udf_expand_file_adinicb(inode); 157 if (err) { 158 inode_unlock(inode); 159 udf_debug("udf_expand_adinicb: err=%d\n", err); 160 return err; 161 } 162 } else { 163 iinfo->i_lenAlloc = max(end, inode->i_size); 164 up_write(&iinfo->i_data_sem); 165 } 166 } else 167 up_write(&iinfo->i_data_sem); 168 169 retval = __generic_file_write_iter(iocb, from); 170 out: 171 inode_unlock(inode); 172 173 if (retval > 0) { 174 mark_inode_dirty(inode); 175 retval = generic_write_sync(iocb, retval); 176 } 177 178 return retval; 179 } 180 181 long udf_ioctl(struct file *filp, unsigned int cmd, unsigned long arg) 182 { 183 struct inode *inode = file_inode(filp); 184 long old_block, new_block; 185 int result; 186 187 if (inode_permission(inode, MAY_READ) != 0) { 188 udf_debug("no permission to access inode %lu\n", inode->i_ino); 189 return -EPERM; 190 } 191 192 if (!arg && ((cmd == UDF_GETVOLIDENT) || (cmd == UDF_GETEASIZE) || 193 (cmd == UDF_RELOCATE_BLOCKS) || (cmd == UDF_GETEABLOCK))) { 194 udf_debug("invalid argument to udf_ioctl\n"); 195 return -EINVAL; 196 } 197 198 switch (cmd) { 199 case UDF_GETVOLIDENT: 200 if (copy_to_user((char __user *)arg, 201 UDF_SB(inode->i_sb)->s_volume_ident, 32)) 202 return -EFAULT; 203 return 0; 204 case UDF_RELOCATE_BLOCKS: 205 if (!capable(CAP_SYS_ADMIN)) 206 return -EPERM; 207 if (get_user(old_block, (long __user *)arg)) 208 return -EFAULT; 209 result = udf_relocate_blocks(inode->i_sb, 210 old_block, &new_block); 211 if (result == 0) 212 result = put_user(new_block, (long __user *)arg); 213 return result; 214 case UDF_GETEASIZE: 215 return put_user(UDF_I(inode)->i_lenEAttr, (int __user *)arg); 216 case UDF_GETEABLOCK: 217 return copy_to_user((char __user *)arg, 218 UDF_I(inode)->i_ext.i_data, 219 UDF_I(inode)->i_lenEAttr) ? -EFAULT : 0; 220 default: 221 return -ENOIOCTLCMD; 222 } 223 224 return 0; 225 } 226 227 static int udf_release_file(struct inode *inode, struct file *filp) 228 { 229 if (filp->f_mode & FMODE_WRITE && 230 atomic_read(&inode->i_writecount) == 1) { 231 /* 232 * Grab i_mutex to avoid races with writes changing i_size 233 * while we are running. 234 */ 235 inode_lock(inode); 236 down_write(&UDF_I(inode)->i_data_sem); 237 udf_discard_prealloc(inode); 238 udf_truncate_tail_extent(inode); 239 up_write(&UDF_I(inode)->i_data_sem); 240 inode_unlock(inode); 241 } 242 return 0; 243 } 244 245 const struct file_operations udf_file_operations = { 246 .read_iter = generic_file_read_iter, 247 .unlocked_ioctl = udf_ioctl, 248 .open = generic_file_open, 249 .mmap = generic_file_mmap, 250 .write_iter = udf_file_write_iter, 251 .release = udf_release_file, 252 .fsync = generic_file_fsync, 253 .splice_read = generic_file_splice_read, 254 .llseek = generic_file_llseek, 255 }; 256 257 static int udf_setattr(struct dentry *dentry, 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(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(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