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 setattr_copy(inode, attr);
284 mark_inode_dirty(inode);
285 return 0;
286 }
287
288 const struct inode_operations udf_file_inode_operations = {
289 .setattr = udf_setattr,
290 };
291
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