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-rw-r--r--fs/ecryptfs/mmap.c788
1 files changed, 788 insertions, 0 deletions
diff --git a/fs/ecryptfs/mmap.c b/fs/ecryptfs/mmap.c
new file mode 100644
index 000000000000..924dd90a4cf5
--- /dev/null
+++ b/fs/ecryptfs/mmap.c
@@ -0,0 +1,788 @@
1/**
2 * eCryptfs: Linux filesystem encryption layer
3 * This is where eCryptfs coordinates the symmetric encryption and
4 * decryption of the file data as it passes between the lower
5 * encrypted file and the upper decrypted file.
6 *
7 * Copyright (C) 1997-2003 Erez Zadok
8 * Copyright (C) 2001-2003 Stony Brook University
9 * Copyright (C) 2004-2006 International Business Machines Corp.
10 * Author(s): Michael A. Halcrow <mahalcro@us.ibm.com>
11 *
12 * This program is free software; you can redistribute it and/or
13 * modify it under the terms of the GNU General Public License as
14 * published by the Free Software Foundation; either version 2 of the
15 * License, or (at your option) any later version.
16 *
17 * This program is distributed in the hope that it will be useful, but
18 * WITHOUT ANY WARRANTY; without even the implied warranty of
19 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
20 * General Public License for more details.
21 *
22 * You should have received a copy of the GNU General Public License
23 * along with this program; if not, write to the Free Software
24 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
25 * 02111-1307, USA.
26 */
27
28#include <linux/pagemap.h>
29#include <linux/writeback.h>
30#include <linux/page-flags.h>
31#include <linux/mount.h>
32#include <linux/file.h>
33#include <linux/crypto.h>
34#include <linux/scatterlist.h>
35#include "ecryptfs_kernel.h"
36
37struct kmem_cache *ecryptfs_lower_page_cache;
38
39/**
40 * ecryptfs_get1page
41 *
42 * Get one page from cache or lower f/s, return error otherwise.
43 *
44 * Returns unlocked and up-to-date page (if ok), with increased
45 * refcnt.
46 */
47static struct page *ecryptfs_get1page(struct file *file, int index)
48{
49 struct page *page;
50 struct dentry *dentry;
51 struct inode *inode;
52 struct address_space *mapping;
53
54 dentry = file->f_dentry;
55 inode = dentry->d_inode;
56 mapping = inode->i_mapping;
57 page = read_cache_page(mapping, index,
58 (filler_t *)mapping->a_ops->readpage,
59 (void *)file);
60 if (IS_ERR(page))
61 goto out;
62 wait_on_page_locked(page);
63out:
64 return page;
65}
66
67static
68int write_zeros(struct file *file, pgoff_t index, int start, int num_zeros);
69
70/**
71 * ecryptfs_fill_zeros
72 * @file: The ecryptfs file
73 * @new_length: The new length of the data in the underlying file;
74 * everything between the prior end of the file and the
75 * new end of the file will be filled with zero's.
76 * new_length must be greater than current length
77 *
78 * Function for handling lseek-ing past the end of the file.
79 *
80 * This function does not support shrinking, only growing a file.
81 *
82 * Returns zero on success; non-zero otherwise.
83 */
84int ecryptfs_fill_zeros(struct file *file, loff_t new_length)
85{
86 int rc = 0;
87 struct dentry *dentry = file->f_dentry;
88 struct inode *inode = dentry->d_inode;
89 pgoff_t old_end_page_index = 0;
90 pgoff_t index = old_end_page_index;
91 int old_end_pos_in_page = -1;
92 pgoff_t new_end_page_index;
93 int new_end_pos_in_page;
94 loff_t cur_length = i_size_read(inode);
95
96 if (cur_length != 0) {
97 index = old_end_page_index =
98 ((cur_length - 1) >> PAGE_CACHE_SHIFT);
99 old_end_pos_in_page = ((cur_length - 1) & ~PAGE_CACHE_MASK);
100 }
101 new_end_page_index = ((new_length - 1) >> PAGE_CACHE_SHIFT);
102 new_end_pos_in_page = ((new_length - 1) & ~PAGE_CACHE_MASK);
103 ecryptfs_printk(KERN_DEBUG, "old_end_page_index = [0x%.16x]; "
104 "old_end_pos_in_page = [%d]; "
105 "new_end_page_index = [0x%.16x]; "
106 "new_end_pos_in_page = [%d]\n",
107 old_end_page_index, old_end_pos_in_page,
108 new_end_page_index, new_end_pos_in_page);
109 if (old_end_page_index == new_end_page_index) {
110 /* Start and end are in the same page; we just need to
111 * set a portion of the existing page to zero's */
112 rc = write_zeros(file, index, (old_end_pos_in_page + 1),
113 (new_end_pos_in_page - old_end_pos_in_page));
114 if (rc)
115 ecryptfs_printk(KERN_ERR, "write_zeros(file=[%p], "
116 "index=[0x%.16x], "
117 "old_end_pos_in_page=[d], "
118 "(PAGE_CACHE_SIZE - new_end_pos_in_page"
119 "=[%d]"
120 ")=[d]) returned [%d]\n", file, index,
121 old_end_pos_in_page,
122 new_end_pos_in_page,
123 (PAGE_CACHE_SIZE - new_end_pos_in_page),
124 rc);
125 goto out;
126 }
127 /* Fill the remainder of the previous last page with zeros */
128 rc = write_zeros(file, index, (old_end_pos_in_page + 1),
129 ((PAGE_CACHE_SIZE - 1) - old_end_pos_in_page));
130 if (rc) {
131 ecryptfs_printk(KERN_ERR, "write_zeros(file=[%p], "
132 "index=[0x%.16x], old_end_pos_in_page=[d], "
133 "(PAGE_CACHE_SIZE - old_end_pos_in_page)=[d]) "
134 "returned [%d]\n", file, index,
135 old_end_pos_in_page,
136 (PAGE_CACHE_SIZE - old_end_pos_in_page), rc);
137 goto out;
138 }
139 index++;
140 while (index < new_end_page_index) {
141 /* Fill all intermediate pages with zeros */
142 rc = write_zeros(file, index, 0, PAGE_CACHE_SIZE);
143 if (rc) {
144 ecryptfs_printk(KERN_ERR, "write_zeros(file=[%p], "
145 "index=[0x%.16x], "
146 "old_end_pos_in_page=[d], "
147 "(PAGE_CACHE_SIZE - new_end_pos_in_page"
148 "=[%d]"
149 ")=[d]) returned [%d]\n", file, index,
150 old_end_pos_in_page,
151 new_end_pos_in_page,
152 (PAGE_CACHE_SIZE - new_end_pos_in_page),
153 rc);
154 goto out;
155 }
156 index++;
157 }
158 /* Fill the portion at the beginning of the last new page with
159 * zero's */
160 rc = write_zeros(file, index, 0, (new_end_pos_in_page + 1));
161 if (rc) {
162 ecryptfs_printk(KERN_ERR, "write_zeros(file="
163 "[%p], index=[0x%.16x], 0, "
164 "new_end_pos_in_page=[%d]"
165 "returned [%d]\n", file, index,
166 new_end_pos_in_page, rc);
167 goto out;
168 }
169out:
170 return rc;
171}
172
173/**
174 * ecryptfs_writepage
175 * @page: Page that is locked before this call is made
176 *
177 * Returns zero on success; non-zero otherwise
178 */
179static int ecryptfs_writepage(struct page *page, struct writeback_control *wbc)
180{
181 struct ecryptfs_page_crypt_context ctx;
182 int rc;
183
184 ctx.page = page;
185 ctx.mode = ECRYPTFS_WRITEPAGE_MODE;
186 ctx.param.wbc = wbc;
187 rc = ecryptfs_encrypt_page(&ctx);
188 if (rc) {
189 ecryptfs_printk(KERN_WARNING, "Error encrypting "
190 "page (upper index [0x%.16x])\n", page->index);
191 ClearPageUptodate(page);
192 goto out;
193 }
194 SetPageUptodate(page);
195 unlock_page(page);
196out:
197 return rc;
198}
199
200/**
201 * Reads the data from the lower file file at index lower_page_index
202 * and copies that data into page.
203 *
204 * @param page Page to fill
205 * @param lower_page_index Index of the page in the lower file to get
206 */
207int ecryptfs_do_readpage(struct file *file, struct page *page,
208 pgoff_t lower_page_index)
209{
210 int rc;
211 struct dentry *dentry;
212 struct file *lower_file;
213 struct dentry *lower_dentry;
214 struct inode *inode;
215 struct inode *lower_inode;
216 char *page_data;
217 struct page *lower_page = NULL;
218 char *lower_page_data;
219 const struct address_space_operations *lower_a_ops;
220
221 dentry = file->f_dentry;
222 lower_file = ecryptfs_file_to_lower(file);
223 lower_dentry = ecryptfs_dentry_to_lower(dentry);
224 inode = dentry->d_inode;
225 lower_inode = ecryptfs_inode_to_lower(inode);
226 lower_a_ops = lower_inode->i_mapping->a_ops;
227 lower_page = read_cache_page(lower_inode->i_mapping, lower_page_index,
228 (filler_t *)lower_a_ops->readpage,
229 (void *)lower_file);
230 if (IS_ERR(lower_page)) {
231 rc = PTR_ERR(lower_page);
232 lower_page = NULL;
233 ecryptfs_printk(KERN_ERR, "Error reading from page cache\n");
234 goto out;
235 }
236 wait_on_page_locked(lower_page);
237 page_data = (char *)kmap(page);
238 if (!page_data) {
239 rc = -ENOMEM;
240 ecryptfs_printk(KERN_ERR, "Error mapping page\n");
241 goto out;
242 }
243 lower_page_data = (char *)kmap(lower_page);
244 if (!lower_page_data) {
245 rc = -ENOMEM;
246 ecryptfs_printk(KERN_ERR, "Error mapping page\n");
247 kunmap(page);
248 goto out;
249 }
250 memcpy(page_data, lower_page_data, PAGE_CACHE_SIZE);
251 kunmap(lower_page);
252 kunmap(page);
253 rc = 0;
254out:
255 if (likely(lower_page))
256 page_cache_release(lower_page);
257 if (rc == 0)
258 SetPageUptodate(page);
259 else
260 ClearPageUptodate(page);
261 return rc;
262}
263
264/**
265 * ecryptfs_readpage
266 * @file: This is an ecryptfs file
267 * @page: ecryptfs associated page to stick the read data into
268 *
269 * Read in a page, decrypting if necessary.
270 *
271 * Returns zero on success; non-zero on error.
272 */
273static int ecryptfs_readpage(struct file *file, struct page *page)
274{
275 int rc = 0;
276 struct ecryptfs_crypt_stat *crypt_stat;
277
278 BUG_ON(!(file && file->f_dentry && file->f_dentry->d_inode));
279 crypt_stat =
280 &ecryptfs_inode_to_private(file->f_dentry->d_inode)->crypt_stat;
281 if (!crypt_stat
282 || !ECRYPTFS_CHECK_FLAG(crypt_stat->flags, ECRYPTFS_ENCRYPTED)
283 || ECRYPTFS_CHECK_FLAG(crypt_stat->flags, ECRYPTFS_NEW_FILE)) {
284 ecryptfs_printk(KERN_DEBUG,
285 "Passing through unencrypted page\n");
286 rc = ecryptfs_do_readpage(file, page, page->index);
287 if (rc) {
288 ecryptfs_printk(KERN_ERR, "Error reading page; rc = "
289 "[%d]\n", rc);
290 goto out;
291 }
292 } else {
293 rc = ecryptfs_decrypt_page(file, page);
294 if (rc) {
295
296 ecryptfs_printk(KERN_ERR, "Error decrypting page; "
297 "rc = [%d]\n", rc);
298 goto out;
299 }
300 }
301 SetPageUptodate(page);
302out:
303 if (rc)
304 ClearPageUptodate(page);
305 ecryptfs_printk(KERN_DEBUG, "Unlocking page with index = [0x%.16x]\n",
306 page->index);
307 unlock_page(page);
308 return rc;
309}
310
311static int fill_zeros_to_end_of_page(struct page *page, unsigned int to)
312{
313 struct inode *inode = page->mapping->host;
314 int end_byte_in_page;
315 int rc = 0;
316 char *page_virt;
317
318 if ((i_size_read(inode) / PAGE_CACHE_SIZE) == page->index) {
319 end_byte_in_page = i_size_read(inode) % PAGE_CACHE_SIZE;
320 if (to > end_byte_in_page)
321 end_byte_in_page = to;
322 page_virt = kmap(page);
323 if (!page_virt) {
324 rc = -ENOMEM;
325 ecryptfs_printk(KERN_WARNING,
326 "Could not map page\n");
327 goto out;
328 }
329 memset((page_virt + end_byte_in_page), 0,
330 (PAGE_CACHE_SIZE - end_byte_in_page));
331 kunmap(page);
332 }
333out:
334 return rc;
335}
336
337static int ecryptfs_prepare_write(struct file *file, struct page *page,
338 unsigned from, unsigned to)
339{
340 int rc = 0;
341
342 kmap(page);
343 if (from == 0 && to == PAGE_CACHE_SIZE)
344 goto out; /* If we are writing a full page, it will be
345 up to date. */
346 if (!PageUptodate(page))
347 rc = ecryptfs_do_readpage(file, page, page->index);
348out:
349 return rc;
350}
351
352int ecryptfs_grab_and_map_lower_page(struct page **lower_page,
353 char **lower_virt,
354 struct inode *lower_inode,
355 unsigned long lower_page_index)
356{
357 int rc = 0;
358
359 (*lower_page) = grab_cache_page(lower_inode->i_mapping,
360 lower_page_index);
361 if (!(*lower_page)) {
362 ecryptfs_printk(KERN_ERR, "grab_cache_page for "
363 "lower_page_index = [0x%.16x] failed\n",
364 lower_page_index);
365 rc = -EINVAL;
366 goto out;
367 }
368 if (lower_virt)
369 (*lower_virt) = kmap((*lower_page));
370 else
371 kmap((*lower_page));
372out:
373 return rc;
374}
375
376int ecryptfs_writepage_and_release_lower_page(struct page *lower_page,
377 struct inode *lower_inode,
378 struct writeback_control *wbc)
379{
380 int rc = 0;
381
382 rc = lower_inode->i_mapping->a_ops->writepage(lower_page, wbc);
383 if (rc) {
384 ecryptfs_printk(KERN_ERR, "Error calling lower writepage(); "
385 "rc = [%d]\n", rc);
386 goto out;
387 }
388 lower_inode->i_mtime = lower_inode->i_ctime = CURRENT_TIME;
389 page_cache_release(lower_page);
390out:
391 return rc;
392}
393
394static void ecryptfs_unmap_and_release_lower_page(struct page *lower_page)
395{
396 kunmap(lower_page);
397 ecryptfs_printk(KERN_DEBUG, "Unlocking lower page with index = "
398 "[0x%.16x]\n", lower_page->index);
399 unlock_page(lower_page);
400 page_cache_release(lower_page);
401}
402
403/**
404 * ecryptfs_write_inode_size_to_header
405 *
406 * Writes the lower file size to the first 8 bytes of the header.
407 *
408 * Returns zero on success; non-zero on error.
409 */
410int
411ecryptfs_write_inode_size_to_header(struct file *lower_file,
412 struct inode *lower_inode,
413 struct inode *inode)
414{
415 int rc = 0;
416 struct page *header_page;
417 char *header_virt;
418 const struct address_space_operations *lower_a_ops;
419 u64 file_size;
420
421 rc = ecryptfs_grab_and_map_lower_page(&header_page, &header_virt,
422 lower_inode, 0);
423 if (rc) {
424 ecryptfs_printk(KERN_ERR, "grab_cache_page for header page "
425 "failed\n");
426 goto out;
427 }
428 lower_a_ops = lower_inode->i_mapping->a_ops;
429 rc = lower_a_ops->prepare_write(lower_file, header_page, 0, 8);
430 file_size = (u64)i_size_read(inode);
431 ecryptfs_printk(KERN_DEBUG, "Writing size: [0x%.16x]\n", file_size);
432 file_size = cpu_to_be64(file_size);
433 memcpy(header_virt, &file_size, sizeof(u64));
434 rc = lower_a_ops->commit_write(lower_file, header_page, 0, 8);
435 if (rc < 0)
436 ecryptfs_printk(KERN_ERR, "Error commiting header page "
437 "write\n");
438 ecryptfs_unmap_and_release_lower_page(header_page);
439 lower_inode->i_mtime = lower_inode->i_ctime = CURRENT_TIME;
440 mark_inode_dirty_sync(inode);
441out:
442 return rc;
443}
444
445int ecryptfs_get_lower_page(struct page **lower_page, struct inode *lower_inode,
446 struct file *lower_file,
447 unsigned long lower_page_index, int byte_offset,
448 int region_bytes)
449{
450 int rc = 0;
451
452 rc = ecryptfs_grab_and_map_lower_page(lower_page, NULL, lower_inode,
453 lower_page_index);
454 if (rc) {
455 ecryptfs_printk(KERN_ERR, "Error attempting to grab and map "
456 "lower page with index [0x%.16x]\n",
457 lower_page_index);
458 goto out;
459 }
460 rc = lower_inode->i_mapping->a_ops->prepare_write(lower_file,
461 (*lower_page),
462 byte_offset,
463 region_bytes);
464 if (rc) {
465 ecryptfs_printk(KERN_ERR, "prepare_write for "
466 "lower_page_index = [0x%.16x] failed; rc = "
467 "[%d]\n", lower_page_index, rc);
468 }
469out:
470 if (rc && (*lower_page)) {
471 ecryptfs_unmap_and_release_lower_page(*lower_page);
472 (*lower_page) = NULL;
473 }
474 return rc;
475}
476
477/**
478 * ecryptfs_commit_lower_page
479 *
480 * Returns zero on success; non-zero on error
481 */
482int
483ecryptfs_commit_lower_page(struct page *lower_page, struct inode *lower_inode,
484 struct file *lower_file, int byte_offset,
485 int region_size)
486{
487 int rc = 0;
488
489 rc = lower_inode->i_mapping->a_ops->commit_write(
490 lower_file, lower_page, byte_offset, region_size);
491 if (rc < 0) {
492 ecryptfs_printk(KERN_ERR,
493 "Error committing write; rc = [%d]\n", rc);
494 } else
495 rc = 0;
496 ecryptfs_unmap_and_release_lower_page(lower_page);
497 return rc;
498}
499
500/**
501 * ecryptfs_copy_page_to_lower
502 *
503 * Used for plaintext pass-through; no page index interpolation
504 * required.
505 */
506int ecryptfs_copy_page_to_lower(struct page *page, struct inode *lower_inode,
507 struct file *lower_file)
508{
509 int rc = 0;
510 struct page *lower_page;
511
512 rc = ecryptfs_get_lower_page(&lower_page, lower_inode, lower_file,
513 page->index, 0, PAGE_CACHE_SIZE);
514 if (rc) {
515 ecryptfs_printk(KERN_ERR, "Error attempting to get page "
516 "at index [0x%.16x]\n", page->index);
517 goto out;
518 }
519 /* TODO: aops */
520 memcpy((char *)page_address(lower_page), page_address(page),
521 PAGE_CACHE_SIZE);
522 rc = ecryptfs_commit_lower_page(lower_page, lower_inode, lower_file,
523 0, PAGE_CACHE_SIZE);
524 if (rc)
525 ecryptfs_printk(KERN_ERR, "Error attempting to commit page "
526 "at index [0x%.16x]\n", page->index);
527out:
528 return rc;
529}
530
531static int
532process_new_file(struct ecryptfs_crypt_stat *crypt_stat,
533 struct file *file, struct inode *inode)
534{
535 struct page *header_page;
536 const struct address_space_operations *lower_a_ops;
537 struct inode *lower_inode;
538 struct file *lower_file;
539 char *header_virt;
540 int rc = 0;
541 int current_header_page = 0;
542 int header_pages;
543 int more_header_data_to_be_written = 1;
544
545 lower_inode = ecryptfs_inode_to_lower(inode);
546 lower_file = ecryptfs_file_to_lower(file);
547 lower_a_ops = lower_inode->i_mapping->a_ops;
548 header_pages = ((crypt_stat->header_extent_size
549 * crypt_stat->num_header_extents_at_front)
550 / PAGE_CACHE_SIZE);
551 BUG_ON(header_pages < 1);
552 while (current_header_page < header_pages) {
553 rc = ecryptfs_grab_and_map_lower_page(&header_page,
554 &header_virt,
555 lower_inode,
556 current_header_page);
557 if (rc) {
558 ecryptfs_printk(KERN_ERR, "grab_cache_page for "
559 "header page [%d] failed; rc = [%d]\n",
560 current_header_page, rc);
561 goto out;
562 }
563 rc = lower_a_ops->prepare_write(lower_file, header_page, 0,
564 PAGE_CACHE_SIZE);
565 if (rc) {
566 ecryptfs_printk(KERN_ERR, "Error preparing to write "
567 "header page out; rc = [%d]\n", rc);
568 goto out;
569 }
570 memset(header_virt, 0, PAGE_CACHE_SIZE);
571 if (more_header_data_to_be_written) {
572 rc = ecryptfs_write_headers_virt(header_virt,
573 crypt_stat,
574 file->f_dentry);
575 if (rc) {
576 ecryptfs_printk(KERN_WARNING, "Error "
577 "generating header; rc = "
578 "[%d]\n", rc);
579 rc = -EIO;
580 memset(header_virt, 0, PAGE_CACHE_SIZE);
581 ecryptfs_unmap_and_release_lower_page(
582 header_page);
583 goto out;
584 }
585 if (current_header_page == 0)
586 memset(header_virt, 0, 8);
587 more_header_data_to_be_written = 0;
588 }
589 rc = lower_a_ops->commit_write(lower_file, header_page, 0,
590 PAGE_CACHE_SIZE);
591 ecryptfs_unmap_and_release_lower_page(header_page);
592 if (rc < 0) {
593 ecryptfs_printk(KERN_ERR,
594 "Error commiting header page write; "
595 "rc = [%d]\n", rc);
596 break;
597 }
598 current_header_page++;
599 }
600 if (rc >= 0) {
601 rc = 0;
602 ecryptfs_printk(KERN_DEBUG, "lower_inode->i_blocks = "
603 "[0x%.16x]\n", lower_inode->i_blocks);
604 i_size_write(inode, 0);
605 lower_inode->i_mtime = lower_inode->i_ctime = CURRENT_TIME;
606 mark_inode_dirty_sync(inode);
607 }
608 ecryptfs_printk(KERN_DEBUG, "Clearing ECRYPTFS_NEW_FILE flag in "
609 "crypt_stat at memory location [%p]\n", crypt_stat);
610 ECRYPTFS_CLEAR_FLAG(crypt_stat->flags, ECRYPTFS_NEW_FILE);
611out:
612 return rc;
613}
614
615/**
616 * ecryptfs_commit_write
617 * @file: The eCryptfs file object
618 * @page: The eCryptfs page
619 * @from: Ignored (we rotate the page IV on each write)
620 * @to: Ignored
621 *
622 * This is where we encrypt the data and pass the encrypted data to
623 * the lower filesystem. In OpenPGP-compatible mode, we operate on
624 * entire underlying packets.
625 */
626static int ecryptfs_commit_write(struct file *file, struct page *page,
627 unsigned from, unsigned to)
628{
629 struct ecryptfs_page_crypt_context ctx;
630 loff_t pos;
631 struct inode *inode;
632 struct inode *lower_inode;
633 struct file *lower_file;
634 struct ecryptfs_crypt_stat *crypt_stat;
635 int rc;
636
637 inode = page->mapping->host;
638 lower_inode = ecryptfs_inode_to_lower(inode);
639 lower_file = ecryptfs_file_to_lower(file);
640 mutex_lock(&lower_inode->i_mutex);
641 crypt_stat =
642 &ecryptfs_inode_to_private(file->f_dentry->d_inode)->crypt_stat;
643 if (ECRYPTFS_CHECK_FLAG(crypt_stat->flags, ECRYPTFS_NEW_FILE)) {
644 ecryptfs_printk(KERN_DEBUG, "ECRYPTFS_NEW_FILE flag set in "
645 "crypt_stat at memory location [%p]\n", crypt_stat);
646 rc = process_new_file(crypt_stat, file, inode);
647 if (rc) {
648 ecryptfs_printk(KERN_ERR, "Error processing new "
649 "file; rc = [%d]\n", rc);
650 goto out;
651 }
652 } else
653 ecryptfs_printk(KERN_DEBUG, "Not a new file\n");
654 ecryptfs_printk(KERN_DEBUG, "Calling fill_zeros_to_end_of_page"
655 "(page w/ index = [0x%.16x], to = [%d])\n", page->index,
656 to);
657 rc = fill_zeros_to_end_of_page(page, to);
658 if (rc) {
659 ecryptfs_printk(KERN_WARNING, "Error attempting to fill "
660 "zeros in page with index = [0x%.16x]\n",
661 page->index);
662 goto out;
663 }
664 ctx.page = page;
665 ctx.mode = ECRYPTFS_PREPARE_COMMIT_MODE;
666 ctx.param.lower_file = lower_file;
667 rc = ecryptfs_encrypt_page(&ctx);
668 if (rc) {
669 ecryptfs_printk(KERN_WARNING, "Error encrypting page (upper "
670 "index [0x%.16x])\n", page->index);
671 goto out;
672 }
673 rc = 0;
674 inode->i_blocks = lower_inode->i_blocks;
675 pos = (page->index << PAGE_CACHE_SHIFT) + to;
676 if (pos > i_size_read(inode)) {
677 i_size_write(inode, pos);
678 ecryptfs_printk(KERN_DEBUG, "Expanded file size to "
679 "[0x%.16x]\n", i_size_read(inode));
680 }
681 ecryptfs_write_inode_size_to_header(lower_file, lower_inode, inode);
682 lower_inode->i_mtime = lower_inode->i_ctime = CURRENT_TIME;
683 mark_inode_dirty_sync(inode);
684out:
685 kunmap(page); /* mapped in prior call (prepare_write) */
686 if (rc < 0)
687 ClearPageUptodate(page);
688 else
689 SetPageUptodate(page);
690 mutex_unlock(&lower_inode->i_mutex);
691 return rc;
692}
693
694/**
695 * write_zeros
696 * @file: The ecryptfs file
697 * @index: The index in which we are writing
698 * @start: The position after the last block of data
699 * @num_zeros: The number of zeros to write
700 *
701 * Write a specified number of zero's to a page.
702 *
703 * (start + num_zeros) must be less than or equal to PAGE_CACHE_SIZE
704 */
705static
706int write_zeros(struct file *file, pgoff_t index, int start, int num_zeros)
707{
708 int rc = 0;
709 struct page *tmp_page;
710
711 tmp_page = ecryptfs_get1page(file, index);
712 if (IS_ERR(tmp_page)) {
713 ecryptfs_printk(KERN_ERR, "Error getting page at index "
714 "[0x%.16x]\n", index);
715 rc = PTR_ERR(tmp_page);
716 goto out;
717 }
718 kmap(tmp_page);
719 rc = ecryptfs_prepare_write(file, tmp_page, start, start + num_zeros);
720 if (rc) {
721 ecryptfs_printk(KERN_ERR, "Error preparing to write zero's "
722 "to remainder of page at index [0x%.16x]\n",
723 index);
724 kunmap(tmp_page);
725 page_cache_release(tmp_page);
726 goto out;
727 }
728 memset(((char *)page_address(tmp_page) + start), 0, num_zeros);
729 rc = ecryptfs_commit_write(file, tmp_page, start, start + num_zeros);
730 if (rc < 0) {
731 ecryptfs_printk(KERN_ERR, "Error attempting to write zero's "
732 "to remainder of page at index [0x%.16x]\n",
733 index);
734 kunmap(tmp_page);
735 page_cache_release(tmp_page);
736 goto out;
737 }
738 rc = 0;
739 kunmap(tmp_page);
740 page_cache_release(tmp_page);
741out:
742 return rc;
743}
744
745static sector_t ecryptfs_bmap(struct address_space *mapping, sector_t block)
746{
747 int rc = 0;
748 struct inode *inode;
749 struct inode *lower_inode;
750
751 inode = (struct inode *)mapping->host;
752 lower_inode = ecryptfs_inode_to_lower(inode);
753 if (lower_inode->i_mapping->a_ops->bmap)
754 rc = lower_inode->i_mapping->a_ops->bmap(lower_inode->i_mapping,
755 block);
756 return rc;
757}
758
759static void ecryptfs_sync_page(struct page *page)
760{
761 struct inode *inode;
762 struct inode *lower_inode;
763 struct page *lower_page;
764
765 inode = page->mapping->host;
766 lower_inode = ecryptfs_inode_to_lower(inode);
767 /* NOTE: Recently swapped with grab_cache_page(), since
768 * sync_page() just makes sure that pending I/O gets done. */
769 lower_page = find_lock_page(lower_inode->i_mapping, page->index);
770 if (!lower_page) {
771 ecryptfs_printk(KERN_DEBUG, "find_lock_page failed\n");
772 return;
773 }
774 lower_page->mapping->a_ops->sync_page(lower_page);
775 ecryptfs_printk(KERN_DEBUG, "Unlocking page with index = [0x%.16x]\n",
776 lower_page->index);
777 unlock_page(lower_page);
778 page_cache_release(lower_page);
779}
780
781struct address_space_operations ecryptfs_aops = {
782 .writepage = ecryptfs_writepage,
783 .readpage = ecryptfs_readpage,
784 .prepare_write = ecryptfs_prepare_write,
785 .commit_write = ecryptfs_commit_write,
786 .bmap = ecryptfs_bmap,
787 .sync_page = ecryptfs_sync_page,
788};
generated by cgit v1.2.2 (git 2.25.0) at 2024-11-28 07:34:17 -0500