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.
7 * Copyright (C) 1997-2003 Erez Zadok
8 * Copyright (C) 2001-2003 Stony Brook University
9 * Copyright (C) 2004-2007 International Business Machines Corp.
10 * Author(s): Michael A. Halcrow <mahalcro@us.ibm.com>
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.
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.
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
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"
37 struct kmem_cache
*ecryptfs_lower_page_cache
;
42 * Get one page from cache or lower f/s, return error otherwise.
44 * Returns unlocked and up-to-date page (if ok), with increased
47 struct page
*ecryptfs_get1page(struct file
*file
, loff_t index
)
49 struct dentry
*dentry
;
51 struct address_space
*mapping
;
53 dentry
= file
->f_path
.dentry
;
54 inode
= dentry
->d_inode
;
55 mapping
= inode
->i_mapping
;
56 return read_mapping_page(mapping
, index
, (void *)file
);
61 * @file: The ecryptfs file
62 * @new_length: The new length of the data in the underlying file;
63 * everything between the prior end of the file and the
64 * new end of the file will be filled with zero's.
65 * new_length must be greater than current length
67 * Function for handling lseek-ing past the end of the file.
69 * This function does not support shrinking, only growing a file.
71 * Returns zero on success; non-zero otherwise.
73 int ecryptfs_fill_zeros(struct file
*file
, loff_t new_length
)
76 struct dentry
*dentry
= file
->f_path
.dentry
;
77 struct inode
*inode
= dentry
->d_inode
;
78 pgoff_t old_end_page_index
= 0;
79 pgoff_t index
= old_end_page_index
;
80 int old_end_pos_in_page
= -1;
81 pgoff_t new_end_page_index
;
82 int new_end_pos_in_page
;
83 loff_t cur_length
= i_size_read(inode
);
85 if (cur_length
!= 0) {
86 index
= old_end_page_index
=
87 ((cur_length
- 1) >> PAGE_CACHE_SHIFT
);
88 old_end_pos_in_page
= ((cur_length
- 1) & ~PAGE_CACHE_MASK
);
90 new_end_page_index
= ((new_length
- 1) >> PAGE_CACHE_SHIFT
);
91 new_end_pos_in_page
= ((new_length
- 1) & ~PAGE_CACHE_MASK
);
92 ecryptfs_printk(KERN_DEBUG
, "old_end_page_index = [0x%.16x]; "
93 "old_end_pos_in_page = [%d]; "
94 "new_end_page_index = [0x%.16x]; "
95 "new_end_pos_in_page = [%d]\n",
96 old_end_page_index
, old_end_pos_in_page
,
97 new_end_page_index
, new_end_pos_in_page
);
98 if (old_end_page_index
== new_end_page_index
) {
99 /* Start and end are in the same page; we just need to
100 * set a portion of the existing page to zero's */
101 rc
= ecryptfs_write_zeros(file
, index
,
102 (old_end_pos_in_page
+ 1),
104 - old_end_pos_in_page
));
106 ecryptfs_printk(KERN_ERR
, "ecryptfs_write_zeros("
109 "old_end_pos_in_page=[d], "
110 "(PAGE_CACHE_SIZE - new_end_pos_in_page"
112 ")=[d]) returned [%d]\n", file
, index
,
115 (PAGE_CACHE_SIZE
- new_end_pos_in_page
),
119 /* Fill the remainder of the previous last page with zeros */
120 rc
= ecryptfs_write_zeros(file
, index
, (old_end_pos_in_page
+ 1),
121 ((PAGE_CACHE_SIZE
- 1) - old_end_pos_in_page
));
123 ecryptfs_printk(KERN_ERR
, "ecryptfs_write_zeros(file=[%p], "
124 "index=[0x%.16x], old_end_pos_in_page=[d], "
125 "(PAGE_CACHE_SIZE - old_end_pos_in_page)=[d]) "
126 "returned [%d]\n", file
, index
,
128 (PAGE_CACHE_SIZE
- old_end_pos_in_page
), rc
);
132 while (index
< new_end_page_index
) {
133 /* Fill all intermediate pages with zeros */
134 rc
= ecryptfs_write_zeros(file
, index
, 0, PAGE_CACHE_SIZE
);
136 ecryptfs_printk(KERN_ERR
, "ecryptfs_write_zeros("
139 "old_end_pos_in_page=[d], "
140 "(PAGE_CACHE_SIZE - new_end_pos_in_page"
142 ")=[d]) returned [%d]\n", file
, index
,
145 (PAGE_CACHE_SIZE
- new_end_pos_in_page
),
151 /* Fill the portion at the beginning of the last new page with
153 rc
= ecryptfs_write_zeros(file
, index
, 0, (new_end_pos_in_page
+ 1));
155 ecryptfs_printk(KERN_ERR
, "ecryptfs_write_zeros(file="
156 "[%p], index=[0x%.16x], 0, "
157 "new_end_pos_in_page=[%d]"
158 "returned [%d]\n", file
, index
,
159 new_end_pos_in_page
, rc
);
168 * @page: Page that is locked before this call is made
170 * Returns zero on success; non-zero otherwise
172 static int ecryptfs_writepage(struct page
*page
, struct writeback_control
*wbc
)
176 rc
= ecryptfs_encrypt_page(page
);
178 ecryptfs_printk(KERN_WARNING
, "Error encrypting "
179 "page (upper index [0x%.16x])\n", page
->index
);
180 ClearPageUptodate(page
);
183 SetPageUptodate(page
);
190 * Reads the data from the lower file file at index lower_page_index
191 * and copies that data into page.
193 * @param page Page to fill
194 * @param lower_page_index Index of the page in the lower file to get
196 int ecryptfs_do_readpage(struct file
*file
, struct page
*page
,
197 pgoff_t lower_page_index
)
200 struct dentry
*dentry
;
201 struct file
*lower_file
;
202 struct dentry
*lower_dentry
;
204 struct inode
*lower_inode
;
206 struct page
*lower_page
= NULL
;
207 char *lower_page_data
;
208 const struct address_space_operations
*lower_a_ops
;
210 dentry
= file
->f_path
.dentry
;
211 lower_file
= ecryptfs_file_to_lower(file
);
212 lower_dentry
= ecryptfs_dentry_to_lower(dentry
);
213 inode
= dentry
->d_inode
;
214 lower_inode
= ecryptfs_inode_to_lower(inode
);
215 lower_a_ops
= lower_inode
->i_mapping
->a_ops
;
216 lower_page
= read_cache_page(lower_inode
->i_mapping
, lower_page_index
,
217 (filler_t
*)lower_a_ops
->readpage
,
219 if (IS_ERR(lower_page
)) {
220 rc
= PTR_ERR(lower_page
);
222 ecryptfs_printk(KERN_ERR
, "Error reading from page cache\n");
225 page_data
= kmap_atomic(page
, KM_USER0
);
226 lower_page_data
= kmap_atomic(lower_page
, KM_USER1
);
227 memcpy(page_data
, lower_page_data
, PAGE_CACHE_SIZE
);
228 kunmap_atomic(lower_page_data
, KM_USER1
);
229 kunmap_atomic(page_data
, KM_USER0
);
230 flush_dcache_page(page
);
233 if (likely(lower_page
))
234 page_cache_release(lower_page
);
236 SetPageUptodate(page
);
238 ClearPageUptodate(page
);
243 * Octets 0-7: Unencrypted file size (big-endian)
244 * Octets 8-15: eCryptfs special marker
245 * Octets 16-19: Flags
246 * Octet 16: File format version number (between 0 and 255)
247 * Octets 17-18: Reserved
248 * Octet 19: Bit 1 (lsb): Reserved
251 * Octets 20-23: Header extent size (big-endian)
252 * Octets 24-25: Number of header extents at front of file
254 * Octet 26: Begin RFC 2440 authentication token packet set
256 static void set_header_info(char *page_virt
,
257 struct ecryptfs_crypt_stat
*crypt_stat
)
260 int save_num_header_extents_at_front
=
261 crypt_stat
->num_header_extents_at_front
;
263 crypt_stat
->num_header_extents_at_front
= 1;
264 ecryptfs_write_header_metadata(page_virt
+ 20, crypt_stat
, &written
);
265 crypt_stat
->num_header_extents_at_front
=
266 save_num_header_extents_at_front
;
270 * ecryptfs_copy_up_encrypted_with_header
271 * @page: Sort of a ``virtual'' representation of the encrypted lower
272 * file. The actual lower file does not have the metadata in
273 * the header. This is locked.
274 * @crypt_stat: The eCryptfs inode's cryptographic context
276 * The ``view'' is the version of the file that userspace winds up
277 * seeing, with the header information inserted.
280 ecryptfs_copy_up_encrypted_with_header(struct page
*page
,
281 struct ecryptfs_crypt_stat
*crypt_stat
)
283 loff_t extent_num_in_page
= 0;
284 loff_t num_extents_per_page
= (PAGE_CACHE_SIZE
285 / crypt_stat
->extent_size
);
288 while (extent_num_in_page
< num_extents_per_page
) {
289 loff_t view_extent_num
= ((page
->index
* num_extents_per_page
)
290 + extent_num_in_page
);
292 if (view_extent_num
< crypt_stat
->num_header_extents_at_front
) {
293 /* This is a header extent */
296 page_virt
= kmap_atomic(page
, KM_USER0
);
297 memset(page_virt
, 0, PAGE_CACHE_SIZE
);
298 /* TODO: Support more than one header extent */
299 if (view_extent_num
== 0) {
300 rc
= ecryptfs_read_xattr_region(
301 page_virt
, page
->mapping
->host
);
302 set_header_info(page_virt
, crypt_stat
);
304 kunmap_atomic(page_virt
, KM_USER0
);
305 flush_dcache_page(page
);
307 ClearPageUptodate(page
);
308 printk(KERN_ERR
"%s: Error reading xattr "
309 "region; rc = [%d]\n", __FUNCTION__
, rc
);
312 SetPageUptodate(page
);
314 /* This is an encrypted data extent */
315 loff_t lower_offset
=
317 crypt_stat
->num_header_extents_at_front
)
318 * crypt_stat
->extent_size
);
320 rc
= ecryptfs_read_lower_page_segment(
321 page
, (lower_offset
>> PAGE_CACHE_SHIFT
),
322 (lower_offset
& ~PAGE_CACHE_MASK
),
323 crypt_stat
->extent_size
, page
->mapping
->host
);
325 printk(KERN_ERR
"%s: Error attempting to read "
326 "extent at offset [%lld] in the lower "
327 "file; rc = [%d]\n", __FUNCTION__
,
332 extent_num_in_page
++;
340 * @file: An eCryptfs file
341 * @page: Page from eCryptfs inode mapping into which to stick the read data
343 * Read in a page, decrypting if necessary.
345 * Returns zero on success; non-zero on error.
347 static int ecryptfs_readpage(struct file
*file
, struct page
*page
)
349 struct ecryptfs_crypt_stat
*crypt_stat
=
350 &ecryptfs_inode_to_private(file
->f_path
.dentry
->d_inode
)->crypt_stat
;
354 || !(crypt_stat
->flags
& ECRYPTFS_ENCRYPTED
)
355 || (crypt_stat
->flags
& ECRYPTFS_NEW_FILE
)) {
356 ecryptfs_printk(KERN_DEBUG
,
357 "Passing through unencrypted page\n");
358 rc
= ecryptfs_read_lower_page_segment(page
, page
->index
, 0,
360 page
->mapping
->host
);
361 } else if (crypt_stat
->flags
& ECRYPTFS_VIEW_AS_ENCRYPTED
) {
362 if (crypt_stat
->flags
& ECRYPTFS_METADATA_IN_XATTR
) {
363 rc
= ecryptfs_copy_up_encrypted_with_header(page
,
366 printk(KERN_ERR
"%s: Error attempting to copy "
367 "the encrypted content from the lower "
368 "file whilst inserting the metadata "
369 "from the xattr into the header; rc = "
370 "[%d]\n", __FUNCTION__
, rc
);
375 rc
= ecryptfs_read_lower_page_segment(
376 page
, page
->index
, 0, PAGE_CACHE_SIZE
,
377 page
->mapping
->host
);
379 printk(KERN_ERR
"Error reading page; rc = "
385 rc
= ecryptfs_decrypt_page(page
);
387 ecryptfs_printk(KERN_ERR
, "Error decrypting page; "
393 ecryptfs_printk(KERN_DEBUG
, "Unlocking page with index = [0x%.16x]\n",
400 * Called with lower inode mutex held.
402 static int fill_zeros_to_end_of_page(struct page
*page
, unsigned int to
)
404 struct inode
*inode
= page
->mapping
->host
;
405 int end_byte_in_page
;
407 if ((i_size_read(inode
) / PAGE_CACHE_SIZE
) != page
->index
)
409 end_byte_in_page
= i_size_read(inode
) % PAGE_CACHE_SIZE
;
410 if (to
> end_byte_in_page
)
411 end_byte_in_page
= to
;
412 zero_user_page(page
, end_byte_in_page
,
413 PAGE_CACHE_SIZE
- end_byte_in_page
, KM_USER0
);
419 * eCryptfs does not currently support holes. When writing after a
420 * seek past the end of the file, eCryptfs fills in 0's through to the
421 * current location. The code to fill in the 0's to all the
422 * intermediate pages calls ecryptfs_prepare_write_no_truncate().
425 ecryptfs_prepare_write_no_truncate(struct file
*file
, struct page
*page
,
426 unsigned from
, unsigned to
)
430 if (from
== 0 && to
== PAGE_CACHE_SIZE
)
431 goto out
; /* If we are writing a full page, it will be
433 if (!PageUptodate(page
))
434 rc
= ecryptfs_do_readpage(file
, page
, page
->index
);
439 static int ecryptfs_prepare_write(struct file
*file
, struct page
*page
,
440 unsigned from
, unsigned to
)
444 if (from
== 0 && to
== PAGE_CACHE_SIZE
)
445 goto out
; /* If we are writing a full page, it will be
447 if (!PageUptodate(page
))
448 rc
= ecryptfs_read_lower_page_segment(page
, page
->index
, 0,
450 page
->mapping
->host
);
451 if (page
->index
!= 0) {
452 loff_t end_of_prev_pg_pos
=
453 (((loff_t
)page
->index
<< PAGE_CACHE_SHIFT
) - 1);
455 if (end_of_prev_pg_pos
> i_size_read(page
->mapping
->host
)) {
456 rc
= ecryptfs_truncate(file
->f_path
.dentry
,
459 printk(KERN_ERR
"Error on attempt to "
460 "truncate to (higher) offset [%lld];"
461 " rc = [%d]\n", end_of_prev_pg_pos
, rc
);
465 if (end_of_prev_pg_pos
+ 1 > i_size_read(page
->mapping
->host
))
466 zero_user_page(page
, 0, PAGE_CACHE_SIZE
, KM_USER0
);
472 int ecryptfs_writepage_and_release_lower_page(struct page
*lower_page
,
473 struct inode
*lower_inode
,
474 struct writeback_control
*wbc
)
478 rc
= lower_inode
->i_mapping
->a_ops
->writepage(lower_page
, wbc
);
480 ecryptfs_printk(KERN_ERR
, "Error calling lower writepage(); "
484 lower_inode
->i_mtime
= lower_inode
->i_ctime
= CURRENT_TIME
;
485 page_cache_release(lower_page
);
490 static void ecryptfs_release_lower_page(struct page
*lower_page
)
492 unlock_page(lower_page
);
493 page_cache_release(lower_page
);
497 * ecryptfs_write_inode_size_to_header
499 * Writes the lower file size to the first 8 bytes of the header.
501 * Returns zero on success; non-zero on error.
503 static int ecryptfs_write_inode_size_to_header(struct inode
*ecryptfs_inode
)
506 char *file_size_virt
;
509 file_size_virt
= kmalloc(sizeof(u64
), GFP_KERNEL
);
510 if (!file_size_virt
) {
514 file_size
= (u64
)i_size_read(ecryptfs_inode
);
515 file_size
= cpu_to_be64(file_size
);
516 memcpy(file_size_virt
, &file_size
, sizeof(u64
));
517 rc
= ecryptfs_write_lower(ecryptfs_inode
, file_size_virt
, 0,
519 kfree(file_size_virt
);
521 printk(KERN_ERR
"%s: Error writing file size to header; "
522 "rc = [%d]\n", __FUNCTION__
, rc
);
527 struct kmem_cache
*ecryptfs_xattr_cache
;
529 static int ecryptfs_write_inode_size_to_xattr(struct inode
*ecryptfs_inode
)
533 struct dentry
*lower_dentry
=
534 ecryptfs_inode_to_private(ecryptfs_inode
)->lower_file
->f_dentry
;
535 struct inode
*lower_inode
= lower_dentry
->d_inode
;
539 if (!lower_inode
->i_op
->getxattr
|| !lower_inode
->i_op
->setxattr
) {
541 "No support for setting xattr in lower filesystem\n");
545 xattr_virt
= kmem_cache_alloc(ecryptfs_xattr_cache
, GFP_KERNEL
);
547 printk(KERN_ERR
"Out of memory whilst attempting to write "
548 "inode size to xattr\n");
552 mutex_lock(&lower_inode
->i_mutex
);
553 size
= lower_inode
->i_op
->getxattr(lower_dentry
, ECRYPTFS_XATTR_NAME
,
554 xattr_virt
, PAGE_CACHE_SIZE
);
557 file_size
= (u64
)i_size_read(ecryptfs_inode
);
558 file_size
= cpu_to_be64(file_size
);
559 memcpy(xattr_virt
, &file_size
, sizeof(u64
));
560 rc
= lower_inode
->i_op
->setxattr(lower_dentry
, ECRYPTFS_XATTR_NAME
,
561 xattr_virt
, size
, 0);
562 mutex_unlock(&lower_inode
->i_mutex
);
564 printk(KERN_ERR
"Error whilst attempting to write inode size "
565 "to lower file xattr; rc = [%d]\n", rc
);
566 kmem_cache_free(ecryptfs_xattr_cache
, xattr_virt
);
571 int ecryptfs_write_inode_size_to_metadata(struct inode
*ecryptfs_inode
)
573 struct ecryptfs_crypt_stat
*crypt_stat
;
575 crypt_stat
= &ecryptfs_inode_to_private(ecryptfs_inode
)->crypt_stat
;
576 if (crypt_stat
->flags
& ECRYPTFS_METADATA_IN_XATTR
)
577 return ecryptfs_write_inode_size_to_xattr(ecryptfs_inode
);
579 return ecryptfs_write_inode_size_to_header(ecryptfs_inode
);
582 int ecryptfs_get_lower_page(struct page
**lower_page
, struct inode
*lower_inode
,
583 struct file
*lower_file
,
584 unsigned long lower_page_index
, int byte_offset
,
589 *lower_page
= grab_cache_page(lower_inode
->i_mapping
, lower_page_index
);
590 if (!(*lower_page
)) {
592 ecryptfs_printk(KERN_ERR
, "Error attempting to grab "
593 "lower page with index [0x%.16x]\n",
597 rc
= lower_inode
->i_mapping
->a_ops
->prepare_write(lower_file
,
602 ecryptfs_printk(KERN_ERR
, "prepare_write for "
603 "lower_page_index = [0x%.16x] failed; rc = "
604 "[%d]\n", lower_page_index
, rc
);
605 ecryptfs_release_lower_page(*lower_page
);
606 (*lower_page
) = NULL
;
613 * ecryptfs_commit_lower_page
615 * Returns zero on success; non-zero on error
618 ecryptfs_commit_lower_page(struct page
*lower_page
, struct inode
*lower_inode
,
619 struct file
*lower_file
, int byte_offset
,
624 rc
= lower_inode
->i_mapping
->a_ops
->commit_write(
625 lower_file
, lower_page
, byte_offset
, region_size
);
627 ecryptfs_printk(KERN_ERR
,
628 "Error committing write; rc = [%d]\n", rc
);
631 ecryptfs_release_lower_page(lower_page
);
636 * ecryptfs_copy_page_to_lower
638 * Used for plaintext pass-through; no page index interpolation
641 int ecryptfs_copy_page_to_lower(struct page
*page
, struct inode
*lower_inode
,
642 struct file
*lower_file
)
645 struct page
*lower_page
;
647 rc
= ecryptfs_get_lower_page(&lower_page
, lower_inode
, lower_file
,
648 page
->index
, 0, PAGE_CACHE_SIZE
);
650 ecryptfs_printk(KERN_ERR
, "Error attempting to get page "
651 "at index [0x%.16x]\n", page
->index
);
655 memcpy((char *)page_address(lower_page
), page_address(page
),
657 rc
= ecryptfs_commit_lower_page(lower_page
, lower_inode
, lower_file
,
660 ecryptfs_printk(KERN_ERR
, "Error attempting to commit page "
661 "at index [0x%.16x]\n", page
->index
);
667 * ecryptfs_commit_write
668 * @file: The eCryptfs file object
669 * @page: The eCryptfs page
670 * @from: Ignored (we rotate the page IV on each write)
673 * This is where we encrypt the data and pass the encrypted data to
674 * the lower filesystem. In OpenPGP-compatible mode, we operate on
675 * entire underlying packets.
677 static int ecryptfs_commit_write(struct file
*file
, struct page
*page
,
678 unsigned from
, unsigned to
)
681 struct inode
*ecryptfs_inode
= page
->mapping
->host
;
682 struct ecryptfs_crypt_stat
*crypt_stat
=
683 &ecryptfs_inode_to_private(file
->f_path
.dentry
->d_inode
)->crypt_stat
;
686 if (crypt_stat
->flags
& ECRYPTFS_NEW_FILE
) {
687 ecryptfs_printk(KERN_DEBUG
, "ECRYPTFS_NEW_FILE flag set in "
688 "crypt_stat at memory location [%p]\n", crypt_stat
);
689 crypt_stat
->flags
&= ~(ECRYPTFS_NEW_FILE
);
691 ecryptfs_printk(KERN_DEBUG
, "Not a new file\n");
692 ecryptfs_printk(KERN_DEBUG
, "Calling fill_zeros_to_end_of_page"
693 "(page w/ index = [0x%.16x], to = [%d])\n", page
->index
,
695 /* Fills in zeros if 'to' goes beyond inode size */
696 rc
= fill_zeros_to_end_of_page(page
, to
);
698 ecryptfs_printk(KERN_WARNING
, "Error attempting to fill "
699 "zeros in page with index = [0x%.16x]\n",
703 rc
= ecryptfs_encrypt_page(page
);
705 ecryptfs_printk(KERN_WARNING
, "Error encrypting page (upper "
706 "index [0x%.16x])\n", page
->index
);
709 pos
= (page
->index
<< PAGE_CACHE_SHIFT
) + to
;
710 if (pos
> i_size_read(ecryptfs_inode
)) {
711 i_size_write(ecryptfs_inode
, pos
);
712 ecryptfs_printk(KERN_DEBUG
, "Expanded file size to "
713 "[0x%.16x]\n", i_size_read(ecryptfs_inode
));
715 rc
= ecryptfs_write_inode_size_to_metadata(ecryptfs_inode
);
717 printk(KERN_ERR
"Error writing inode size to metadata; "
724 * ecryptfs_write_zeros
725 * @file: The ecryptfs file
726 * @index: The index in which we are writing
727 * @start: The position after the last block of data
728 * @num_zeros: The number of zeros to write
730 * Write a specified number of zero's to a page.
732 * (start + num_zeros) must be less than or equal to PAGE_CACHE_SIZE
735 ecryptfs_write_zeros(struct file
*file
, pgoff_t index
, int start
, int num_zeros
)
738 struct page
*tmp_page
;
740 tmp_page
= ecryptfs_get1page(file
, index
);
741 if (IS_ERR(tmp_page
)) {
742 ecryptfs_printk(KERN_ERR
, "Error getting page at index "
743 "[0x%.16x]\n", index
);
744 rc
= PTR_ERR(tmp_page
);
747 rc
= ecryptfs_prepare_write_no_truncate(file
, tmp_page
, start
,
748 (start
+ num_zeros
));
750 ecryptfs_printk(KERN_ERR
, "Error preparing to write zero's "
751 "to page at index [0x%.16x]\n",
753 page_cache_release(tmp_page
);
756 zero_user_page(tmp_page
, start
, num_zeros
, KM_USER0
);
757 rc
= ecryptfs_commit_write(file
, tmp_page
, start
, start
+ num_zeros
);
759 ecryptfs_printk(KERN_ERR
, "Error attempting to write zero's "
760 "to remainder of page at index [0x%.16x]\n",
762 page_cache_release(tmp_page
);
766 page_cache_release(tmp_page
);
771 static sector_t
ecryptfs_bmap(struct address_space
*mapping
, sector_t block
)
775 struct inode
*lower_inode
;
777 inode
= (struct inode
*)mapping
->host
;
778 lower_inode
= ecryptfs_inode_to_lower(inode
);
779 if (lower_inode
->i_mapping
->a_ops
->bmap
)
780 rc
= lower_inode
->i_mapping
->a_ops
->bmap(lower_inode
->i_mapping
,
785 struct address_space_operations ecryptfs_aops
= {
786 .writepage
= ecryptfs_writepage
,
787 .readpage
= ecryptfs_readpage
,
788 .prepare_write
= ecryptfs_prepare_write
,
789 .commit_write
= ecryptfs_commit_write
,
790 .bmap
= ecryptfs_bmap
,