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