linux/fs/ecryptfs/mmap.c
Michael Halcrow d4c5cdb3e0 zero out last page for llseek/write
When one llseek's past the end of the file and then writes, every page past
the previous end of the file should be cleared.  Trevor found that the code,
as is, does not assure that the very last page is always cleared.  This patch
takes care of that.

Signed-off-by: Michael Halcrow <mhalcrow@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-06-28 11:34:53 -07:00

852 lines
24 KiB
C

/**
* eCryptfs: Linux filesystem encryption layer
* This is where eCryptfs coordinates the symmetric encryption and
* decryption of the file data as it passes between the lower
* encrypted file and the upper decrypted file.
*
* Copyright (C) 1997-2003 Erez Zadok
* Copyright (C) 2001-2003 Stony Brook University
* Copyright (C) 2004-2007 International Business Machines Corp.
* Author(s): Michael A. Halcrow <mahalcro@us.ibm.com>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation; either version 2 of the
* License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
* 02111-1307, USA.
*/
#include <linux/pagemap.h>
#include <linux/writeback.h>
#include <linux/page-flags.h>
#include <linux/mount.h>
#include <linux/file.h>
#include <linux/crypto.h>
#include <linux/scatterlist.h>
#include "ecryptfs_kernel.h"
struct kmem_cache *ecryptfs_lower_page_cache;
/**
* ecryptfs_get1page
*
* Get one page from cache or lower f/s, return error otherwise.
*
* Returns unlocked and up-to-date page (if ok), with increased
* refcnt.
*/
static struct page *ecryptfs_get1page(struct file *file, int index)
{
struct dentry *dentry;
struct inode *inode;
struct address_space *mapping;
dentry = file->f_path.dentry;
inode = dentry->d_inode;
mapping = inode->i_mapping;
return read_mapping_page(mapping, index, (void *)file);
}
/**
* ecryptfs_fill_zeros
* @file: The ecryptfs file
* @new_length: The new length of the data in the underlying file;
* everything between the prior end of the file and the
* new end of the file will be filled with zero's.
* new_length must be greater than current length
*
* Function for handling lseek-ing past the end of the file.
*
* This function does not support shrinking, only growing a file.
*
* Returns zero on success; non-zero otherwise.
*/
int ecryptfs_fill_zeros(struct file *file, loff_t new_length)
{
int rc = 0;
struct dentry *dentry = file->f_path.dentry;
struct inode *inode = dentry->d_inode;
pgoff_t old_end_page_index = 0;
pgoff_t index = old_end_page_index;
int old_end_pos_in_page = -1;
pgoff_t new_end_page_index;
int new_end_pos_in_page;
loff_t cur_length = i_size_read(inode);
if (cur_length != 0) {
index = old_end_page_index =
((cur_length - 1) >> PAGE_CACHE_SHIFT);
old_end_pos_in_page = ((cur_length - 1) & ~PAGE_CACHE_MASK);
}
new_end_page_index = ((new_length - 1) >> PAGE_CACHE_SHIFT);
new_end_pos_in_page = ((new_length - 1) & ~PAGE_CACHE_MASK);
ecryptfs_printk(KERN_DEBUG, "old_end_page_index = [0x%.16x]; "
"old_end_pos_in_page = [%d]; "
"new_end_page_index = [0x%.16x]; "
"new_end_pos_in_page = [%d]\n",
old_end_page_index, old_end_pos_in_page,
new_end_page_index, new_end_pos_in_page);
if (old_end_page_index == new_end_page_index) {
/* Start and end are in the same page; we just need to
* set a portion of the existing page to zero's */
rc = ecryptfs_write_zeros(file, index,
(old_end_pos_in_page + 1),
(new_end_pos_in_page
- old_end_pos_in_page));
if (rc)
ecryptfs_printk(KERN_ERR, "ecryptfs_write_zeros("
"file=[%p], "
"index=[0x%.16x], "
"old_end_pos_in_page=[d], "
"(PAGE_CACHE_SIZE - new_end_pos_in_page"
"=[%d]"
")=[d]) returned [%d]\n", file, index,
old_end_pos_in_page,
new_end_pos_in_page,
(PAGE_CACHE_SIZE - new_end_pos_in_page),
rc);
goto out;
}
/* Fill the remainder of the previous last page with zeros */
rc = ecryptfs_write_zeros(file, index, (old_end_pos_in_page + 1),
((PAGE_CACHE_SIZE - 1) - old_end_pos_in_page));
if (rc) {
ecryptfs_printk(KERN_ERR, "ecryptfs_write_zeros(file=[%p], "
"index=[0x%.16x], old_end_pos_in_page=[d], "
"(PAGE_CACHE_SIZE - old_end_pos_in_page)=[d]) "
"returned [%d]\n", file, index,
old_end_pos_in_page,
(PAGE_CACHE_SIZE - old_end_pos_in_page), rc);
goto out;
}
index++;
while (index < new_end_page_index) {
/* Fill all intermediate pages with zeros */
rc = ecryptfs_write_zeros(file, index, 0, PAGE_CACHE_SIZE);
if (rc) {
ecryptfs_printk(KERN_ERR, "ecryptfs_write_zeros("
"file=[%p], "
"index=[0x%.16x], "
"old_end_pos_in_page=[d], "
"(PAGE_CACHE_SIZE - new_end_pos_in_page"
"=[%d]"
")=[d]) returned [%d]\n", file, index,
old_end_pos_in_page,
new_end_pos_in_page,
(PAGE_CACHE_SIZE - new_end_pos_in_page),
rc);
goto out;
}
index++;
}
/* Fill the portion at the beginning of the last new page with
* zero's */
rc = ecryptfs_write_zeros(file, index, 0, (new_end_pos_in_page + 1));
if (rc) {
ecryptfs_printk(KERN_ERR, "ecryptfs_write_zeros(file="
"[%p], index=[0x%.16x], 0, "
"new_end_pos_in_page=[%d]"
"returned [%d]\n", file, index,
new_end_pos_in_page, rc);
goto out;
}
out:
return rc;
}
/**
* ecryptfs_writepage
* @page: Page that is locked before this call is made
*
* Returns zero on success; non-zero otherwise
*/
static int ecryptfs_writepage(struct page *page, struct writeback_control *wbc)
{
struct ecryptfs_page_crypt_context ctx;
int rc;
ctx.page = page;
ctx.mode = ECRYPTFS_WRITEPAGE_MODE;
ctx.param.wbc = wbc;
rc = ecryptfs_encrypt_page(&ctx);
if (rc) {
ecryptfs_printk(KERN_WARNING, "Error encrypting "
"page (upper index [0x%.16x])\n", page->index);
ClearPageUptodate(page);
goto out;
}
SetPageUptodate(page);
unlock_page(page);
out:
return rc;
}
/**
* Reads the data from the lower file file at index lower_page_index
* and copies that data into page.
*
* @param page Page to fill
* @param lower_page_index Index of the page in the lower file to get
*/
int ecryptfs_do_readpage(struct file *file, struct page *page,
pgoff_t lower_page_index)
{
int rc;
struct dentry *dentry;
struct file *lower_file;
struct dentry *lower_dentry;
struct inode *inode;
struct inode *lower_inode;
char *page_data;
struct page *lower_page = NULL;
char *lower_page_data;
const struct address_space_operations *lower_a_ops;
dentry = file->f_path.dentry;
lower_file = ecryptfs_file_to_lower(file);
lower_dentry = ecryptfs_dentry_to_lower(dentry);
inode = dentry->d_inode;
lower_inode = ecryptfs_inode_to_lower(inode);
lower_a_ops = lower_inode->i_mapping->a_ops;
lower_page = read_cache_page(lower_inode->i_mapping, lower_page_index,
(filler_t *)lower_a_ops->readpage,
(void *)lower_file);
if (IS_ERR(lower_page)) {
rc = PTR_ERR(lower_page);
lower_page = NULL;
ecryptfs_printk(KERN_ERR, "Error reading from page cache\n");
goto out;
}
page_data = kmap_atomic(page, KM_USER0);
lower_page_data = kmap_atomic(lower_page, KM_USER1);
memcpy(page_data, lower_page_data, PAGE_CACHE_SIZE);
kunmap_atomic(lower_page_data, KM_USER1);
kunmap_atomic(page_data, KM_USER0);
flush_dcache_page(page);
rc = 0;
out:
if (likely(lower_page))
page_cache_release(lower_page);
if (rc == 0)
SetPageUptodate(page);
else
ClearPageUptodate(page);
return rc;
}
/**
* Header Extent:
* Octets 0-7: Unencrypted file size (big-endian)
* Octets 8-15: eCryptfs special marker
* Octets 16-19: Flags
* Octet 16: File format version number (between 0 and 255)
* Octets 17-18: Reserved
* Octet 19: Bit 1 (lsb): Reserved
* Bit 2: Encrypted?
* Bits 3-8: Reserved
* Octets 20-23: Header extent size (big-endian)
* Octets 24-25: Number of header extents at front of file
* (big-endian)
* Octet 26: Begin RFC 2440 authentication token packet set
*/
static void set_header_info(char *page_virt,
struct ecryptfs_crypt_stat *crypt_stat)
{
size_t written;
int save_num_header_extents_at_front =
crypt_stat->num_header_extents_at_front;
crypt_stat->num_header_extents_at_front = 1;
ecryptfs_write_header_metadata(page_virt + 20, crypt_stat, &written);
crypt_stat->num_header_extents_at_front =
save_num_header_extents_at_front;
}
/**
* ecryptfs_readpage
* @file: This is an ecryptfs file
* @page: ecryptfs associated page to stick the read data into
*
* Read in a page, decrypting if necessary.
*
* Returns zero on success; non-zero on error.
*/
static int ecryptfs_readpage(struct file *file, struct page *page)
{
int rc = 0;
struct ecryptfs_crypt_stat *crypt_stat;
BUG_ON(!(file && file->f_path.dentry && file->f_path.dentry->d_inode));
crypt_stat = &ecryptfs_inode_to_private(file->f_path.dentry->d_inode)
->crypt_stat;
if (!crypt_stat
|| !(crypt_stat->flags & ECRYPTFS_ENCRYPTED)
|| (crypt_stat->flags & ECRYPTFS_NEW_FILE)) {
ecryptfs_printk(KERN_DEBUG,
"Passing through unencrypted page\n");
rc = ecryptfs_do_readpage(file, page, page->index);
if (rc) {
ecryptfs_printk(KERN_ERR, "Error reading page; rc = "
"[%d]\n", rc);
goto out;
}
} else if (crypt_stat->flags & ECRYPTFS_VIEW_AS_ENCRYPTED) {
if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR) {
int num_pages_in_header_region =
(crypt_stat->header_extent_size
/ PAGE_CACHE_SIZE);
if (page->index < num_pages_in_header_region) {
char *page_virt;
page_virt = kmap_atomic(page, KM_USER0);
memset(page_virt, 0, PAGE_CACHE_SIZE);
if (page->index == 0) {
rc = ecryptfs_read_xattr_region(
page_virt, file->f_path.dentry);
set_header_info(page_virt, crypt_stat);
}
kunmap_atomic(page_virt, KM_USER0);
flush_dcache_page(page);
if (rc) {
printk(KERN_ERR "Error reading xattr "
"region\n");
goto out;
}
} else {
rc = ecryptfs_do_readpage(
file, page,
(page->index
- num_pages_in_header_region));
if (rc) {
printk(KERN_ERR "Error reading page; "
"rc = [%d]\n", rc);
goto out;
}
}
} else {
rc = ecryptfs_do_readpage(file, page, page->index);
if (rc) {
printk(KERN_ERR "Error reading page; rc = "
"[%d]\n", rc);
goto out;
}
}
} else {
rc = ecryptfs_decrypt_page(file, page);
if (rc) {
ecryptfs_printk(KERN_ERR, "Error decrypting page; "
"rc = [%d]\n", rc);
goto out;
}
}
SetPageUptodate(page);
out:
if (rc)
ClearPageUptodate(page);
ecryptfs_printk(KERN_DEBUG, "Unlocking page with index = [0x%.16x]\n",
page->index);
unlock_page(page);
return rc;
}
/**
* Called with lower inode mutex held.
*/
static int fill_zeros_to_end_of_page(struct page *page, unsigned int to)
{
struct inode *inode = page->mapping->host;
int end_byte_in_page;
if ((i_size_read(inode) / PAGE_CACHE_SIZE) != page->index)
goto out;
end_byte_in_page = i_size_read(inode) % PAGE_CACHE_SIZE;
if (to > end_byte_in_page)
end_byte_in_page = to;
zero_user_page(page, end_byte_in_page,
PAGE_CACHE_SIZE - end_byte_in_page, KM_USER0);
out:
return 0;
}
/**
* eCryptfs does not currently support holes. When writing after a
* seek past the end of the file, eCryptfs fills in 0's through to the
* current location. The code to fill in the 0's to all the
* intermediate pages calls ecryptfs_prepare_write_no_truncate().
*/
static int
ecryptfs_prepare_write_no_truncate(struct file *file, struct page *page,
unsigned from, unsigned to)
{
int rc = 0;
if (from == 0 && to == PAGE_CACHE_SIZE)
goto out; /* If we are writing a full page, it will be
up to date. */
if (!PageUptodate(page))
rc = ecryptfs_do_readpage(file, page, page->index);
out:
return rc;
}
static int ecryptfs_prepare_write(struct file *file, struct page *page,
unsigned from, unsigned to)
{
int rc = 0;
if (from == 0 && to == PAGE_CACHE_SIZE)
goto out; /* If we are writing a full page, it will be
up to date. */
if (!PageUptodate(page))
rc = ecryptfs_do_readpage(file, page, page->index);
if (page->index != 0) {
loff_t end_of_prev_pg_pos =
(((loff_t)page->index << PAGE_CACHE_SHIFT) - 1);
if (end_of_prev_pg_pos > i_size_read(page->mapping->host)) {
rc = ecryptfs_truncate(file->f_path.dentry,
end_of_prev_pg_pos);
if (rc) {
printk(KERN_ERR "Error on attempt to "
"truncate to (higher) offset [%lld];"
" rc = [%d]\n", end_of_prev_pg_pos, rc);
goto out;
}
}
if (end_of_prev_pg_pos + 1 > i_size_read(page->mapping->host))
zero_user_page(page, 0, PAGE_CACHE_SIZE, KM_USER0);
}
out:
return rc;
}
int ecryptfs_writepage_and_release_lower_page(struct page *lower_page,
struct inode *lower_inode,
struct writeback_control *wbc)
{
int rc = 0;
rc = lower_inode->i_mapping->a_ops->writepage(lower_page, wbc);
if (rc) {
ecryptfs_printk(KERN_ERR, "Error calling lower writepage(); "
"rc = [%d]\n", rc);
goto out;
}
lower_inode->i_mtime = lower_inode->i_ctime = CURRENT_TIME;
page_cache_release(lower_page);
out:
return rc;
}
static
void ecryptfs_release_lower_page(struct page *lower_page, int page_locked)
{
if (page_locked)
unlock_page(lower_page);
page_cache_release(lower_page);
}
/**
* ecryptfs_write_inode_size_to_header
*
* Writes the lower file size to the first 8 bytes of the header.
*
* Returns zero on success; non-zero on error.
*/
static int ecryptfs_write_inode_size_to_header(struct file *lower_file,
struct inode *lower_inode,
struct inode *inode)
{
int rc = 0;
struct page *header_page;
char *header_virt;
const struct address_space_operations *lower_a_ops;
u64 file_size;
retry:
header_page = grab_cache_page(lower_inode->i_mapping, 0);
if (!header_page) {
ecryptfs_printk(KERN_ERR, "grab_cache_page for "
"lower_page_index 0 failed\n");
rc = -EINVAL;
goto out;
}
lower_a_ops = lower_inode->i_mapping->a_ops;
rc = lower_a_ops->prepare_write(lower_file, header_page, 0, 8);
if (rc) {
if (rc == AOP_TRUNCATED_PAGE) {
ecryptfs_release_lower_page(header_page, 0);
goto retry;
} else
ecryptfs_release_lower_page(header_page, 1);
goto out;
}
file_size = (u64)i_size_read(inode);
ecryptfs_printk(KERN_DEBUG, "Writing size: [0x%.16x]\n", file_size);
file_size = cpu_to_be64(file_size);
header_virt = kmap_atomic(header_page, KM_USER0);
memcpy(header_virt, &file_size, sizeof(u64));
kunmap_atomic(header_virt, KM_USER0);
flush_dcache_page(header_page);
rc = lower_a_ops->commit_write(lower_file, header_page, 0, 8);
if (rc < 0)
ecryptfs_printk(KERN_ERR, "Error commiting header page "
"write\n");
if (rc == AOP_TRUNCATED_PAGE) {
ecryptfs_release_lower_page(header_page, 0);
goto retry;
} else
ecryptfs_release_lower_page(header_page, 1);
lower_inode->i_mtime = lower_inode->i_ctime = CURRENT_TIME;
mark_inode_dirty_sync(inode);
out:
return rc;
}
static int ecryptfs_write_inode_size_to_xattr(struct inode *lower_inode,
struct inode *inode,
struct dentry *ecryptfs_dentry,
int lower_i_mutex_held)
{
ssize_t size;
void *xattr_virt;
struct dentry *lower_dentry;
u64 file_size;
int rc;
xattr_virt = kmem_cache_alloc(ecryptfs_xattr_cache, GFP_KERNEL);
if (!xattr_virt) {
printk(KERN_ERR "Out of memory whilst attempting to write "
"inode size to xattr\n");
rc = -ENOMEM;
goto out;
}
lower_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry);
if (!lower_dentry->d_inode->i_op->getxattr ||
!lower_dentry->d_inode->i_op->setxattr) {
printk(KERN_WARNING
"No support for setting xattr in lower filesystem\n");
rc = -ENOSYS;
kmem_cache_free(ecryptfs_xattr_cache, xattr_virt);
goto out;
}
if (!lower_i_mutex_held)
mutex_lock(&lower_dentry->d_inode->i_mutex);
size = lower_dentry->d_inode->i_op->getxattr(lower_dentry,
ECRYPTFS_XATTR_NAME,
xattr_virt,
PAGE_CACHE_SIZE);
if (!lower_i_mutex_held)
mutex_unlock(&lower_dentry->d_inode->i_mutex);
if (size < 0)
size = 8;
file_size = (u64)i_size_read(inode);
file_size = cpu_to_be64(file_size);
memcpy(xattr_virt, &file_size, sizeof(u64));
if (!lower_i_mutex_held)
mutex_lock(&lower_dentry->d_inode->i_mutex);
rc = lower_dentry->d_inode->i_op->setxattr(lower_dentry,
ECRYPTFS_XATTR_NAME,
xattr_virt, size, 0);
if (!lower_i_mutex_held)
mutex_unlock(&lower_dentry->d_inode->i_mutex);
if (rc)
printk(KERN_ERR "Error whilst attempting to write inode size "
"to lower file xattr; rc = [%d]\n", rc);
kmem_cache_free(ecryptfs_xattr_cache, xattr_virt);
out:
return rc;
}
int
ecryptfs_write_inode_size_to_metadata(struct file *lower_file,
struct inode *lower_inode,
struct inode *inode,
struct dentry *ecryptfs_dentry,
int lower_i_mutex_held)
{
struct ecryptfs_crypt_stat *crypt_stat;
crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat;
if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR)
return ecryptfs_write_inode_size_to_xattr(lower_inode, inode,
ecryptfs_dentry,
lower_i_mutex_held);
else
return ecryptfs_write_inode_size_to_header(lower_file,
lower_inode,
inode);
}
int ecryptfs_get_lower_page(struct page **lower_page, struct inode *lower_inode,
struct file *lower_file,
unsigned long lower_page_index, int byte_offset,
int region_bytes)
{
int rc = 0;
retry:
*lower_page = grab_cache_page(lower_inode->i_mapping, lower_page_index);
if (!(*lower_page)) {
rc = -EINVAL;
ecryptfs_printk(KERN_ERR, "Error attempting to grab "
"lower page with index [0x%.16x]\n",
lower_page_index);
goto out;
}
rc = lower_inode->i_mapping->a_ops->prepare_write(lower_file,
(*lower_page),
byte_offset,
region_bytes);
if (rc) {
if (rc == AOP_TRUNCATED_PAGE) {
ecryptfs_release_lower_page(*lower_page, 0);
goto retry;
} else {
ecryptfs_printk(KERN_ERR, "prepare_write for "
"lower_page_index = [0x%.16x] failed; rc = "
"[%d]\n", lower_page_index, rc);
ecryptfs_release_lower_page(*lower_page, 1);
(*lower_page) = NULL;
}
}
out:
return rc;
}
/**
* ecryptfs_commit_lower_page
*
* Returns zero on success; non-zero on error
*/
int
ecryptfs_commit_lower_page(struct page *lower_page, struct inode *lower_inode,
struct file *lower_file, int byte_offset,
int region_size)
{
int page_locked = 1;
int rc = 0;
rc = lower_inode->i_mapping->a_ops->commit_write(
lower_file, lower_page, byte_offset, region_size);
if (rc == AOP_TRUNCATED_PAGE)
page_locked = 0;
if (rc < 0) {
ecryptfs_printk(KERN_ERR,
"Error committing write; rc = [%d]\n", rc);
} else
rc = 0;
ecryptfs_release_lower_page(lower_page, page_locked);
return rc;
}
/**
* ecryptfs_copy_page_to_lower
*
* Used for plaintext pass-through; no page index interpolation
* required.
*/
int ecryptfs_copy_page_to_lower(struct page *page, struct inode *lower_inode,
struct file *lower_file)
{
int rc = 0;
struct page *lower_page;
rc = ecryptfs_get_lower_page(&lower_page, lower_inode, lower_file,
page->index, 0, PAGE_CACHE_SIZE);
if (rc) {
ecryptfs_printk(KERN_ERR, "Error attempting to get page "
"at index [0x%.16x]\n", page->index);
goto out;
}
/* TODO: aops */
memcpy((char *)page_address(lower_page), page_address(page),
PAGE_CACHE_SIZE);
rc = ecryptfs_commit_lower_page(lower_page, lower_inode, lower_file,
0, PAGE_CACHE_SIZE);
if (rc)
ecryptfs_printk(KERN_ERR, "Error attempting to commit page "
"at index [0x%.16x]\n", page->index);
out:
return rc;
}
struct kmem_cache *ecryptfs_xattr_cache;
/**
* ecryptfs_commit_write
* @file: The eCryptfs file object
* @page: The eCryptfs page
* @from: Ignored (we rotate the page IV on each write)
* @to: Ignored
*
* This is where we encrypt the data and pass the encrypted data to
* the lower filesystem. In OpenPGP-compatible mode, we operate on
* entire underlying packets.
*/
static int ecryptfs_commit_write(struct file *file, struct page *page,
unsigned from, unsigned to)
{
struct ecryptfs_page_crypt_context ctx;
loff_t pos;
struct inode *inode;
struct inode *lower_inode;
struct file *lower_file;
struct ecryptfs_crypt_stat *crypt_stat;
int rc;
inode = page->mapping->host;
lower_inode = ecryptfs_inode_to_lower(inode);
lower_file = ecryptfs_file_to_lower(file);
mutex_lock(&lower_inode->i_mutex);
crypt_stat = &ecryptfs_inode_to_private(file->f_path.dentry->d_inode)
->crypt_stat;
if (crypt_stat->flags & ECRYPTFS_NEW_FILE) {
ecryptfs_printk(KERN_DEBUG, "ECRYPTFS_NEW_FILE flag set in "
"crypt_stat at memory location [%p]\n", crypt_stat);
crypt_stat->flags &= ~(ECRYPTFS_NEW_FILE);
} else
ecryptfs_printk(KERN_DEBUG, "Not a new file\n");
ecryptfs_printk(KERN_DEBUG, "Calling fill_zeros_to_end_of_page"
"(page w/ index = [0x%.16x], to = [%d])\n", page->index,
to);
rc = fill_zeros_to_end_of_page(page, to);
if (rc) {
ecryptfs_printk(KERN_WARNING, "Error attempting to fill "
"zeros in page with index = [0x%.16x]\n",
page->index);
goto out;
}
ctx.page = page;
ctx.mode = ECRYPTFS_PREPARE_COMMIT_MODE;
ctx.param.lower_file = lower_file;
rc = ecryptfs_encrypt_page(&ctx);
if (rc) {
ecryptfs_printk(KERN_WARNING, "Error encrypting page (upper "
"index [0x%.16x])\n", page->index);
goto out;
}
inode->i_blocks = lower_inode->i_blocks;
pos = (page->index << PAGE_CACHE_SHIFT) + to;
if (pos > i_size_read(inode)) {
i_size_write(inode, pos);
ecryptfs_printk(KERN_DEBUG, "Expanded file size to "
"[0x%.16x]\n", i_size_read(inode));
}
rc = ecryptfs_write_inode_size_to_metadata(lower_file, lower_inode,
inode, file->f_dentry,
ECRYPTFS_LOWER_I_MUTEX_HELD);
if (rc)
printk(KERN_ERR "Error writing inode size to metadata; "
"rc = [%d]\n", rc);
lower_inode->i_mtime = lower_inode->i_ctime = CURRENT_TIME;
mark_inode_dirty_sync(inode);
out:
if (rc < 0)
ClearPageUptodate(page);
else
SetPageUptodate(page);
mutex_unlock(&lower_inode->i_mutex);
return rc;
}
/**
* ecryptfs_write_zeros
* @file: The ecryptfs file
* @index: The index in which we are writing
* @start: The position after the last block of data
* @num_zeros: The number of zeros to write
*
* Write a specified number of zero's to a page.
*
* (start + num_zeros) must be less than or equal to PAGE_CACHE_SIZE
*/
int
ecryptfs_write_zeros(struct file *file, pgoff_t index, int start, int num_zeros)
{
int rc = 0;
struct page *tmp_page;
tmp_page = ecryptfs_get1page(file, index);
if (IS_ERR(tmp_page)) {
ecryptfs_printk(KERN_ERR, "Error getting page at index "
"[0x%.16x]\n", index);
rc = PTR_ERR(tmp_page);
goto out;
}
if ((rc = ecryptfs_prepare_write_no_truncate(file, tmp_page, start,
(start + num_zeros)))) {
ecryptfs_printk(KERN_ERR, "Error preparing to write zero's "
"to page at index [0x%.16x]\n",
index);
page_cache_release(tmp_page);
goto out;
}
zero_user_page(tmp_page, start, num_zeros, KM_USER0);
rc = ecryptfs_commit_write(file, tmp_page, start, start + num_zeros);
if (rc < 0) {
ecryptfs_printk(KERN_ERR, "Error attempting to write zero's "
"to remainder of page at index [0x%.16x]\n",
index);
page_cache_release(tmp_page);
goto out;
}
rc = 0;
page_cache_release(tmp_page);
out:
return rc;
}
static sector_t ecryptfs_bmap(struct address_space *mapping, sector_t block)
{
int rc = 0;
struct inode *inode;
struct inode *lower_inode;
inode = (struct inode *)mapping->host;
lower_inode = ecryptfs_inode_to_lower(inode);
if (lower_inode->i_mapping->a_ops->bmap)
rc = lower_inode->i_mapping->a_ops->bmap(lower_inode->i_mapping,
block);
return rc;
}
static void ecryptfs_sync_page(struct page *page)
{
struct inode *inode;
struct inode *lower_inode;
struct page *lower_page;
inode = page->mapping->host;
lower_inode = ecryptfs_inode_to_lower(inode);
/* NOTE: Recently swapped with grab_cache_page(), since
* sync_page() just makes sure that pending I/O gets done. */
lower_page = find_lock_page(lower_inode->i_mapping, page->index);
if (!lower_page) {
ecryptfs_printk(KERN_DEBUG, "find_lock_page failed\n");
return;
}
lower_page->mapping->a_ops->sync_page(lower_page);
ecryptfs_printk(KERN_DEBUG, "Unlocking page with index = [0x%.16x]\n",
lower_page->index);
unlock_page(lower_page);
page_cache_release(lower_page);
}
struct address_space_operations ecryptfs_aops = {
.writepage = ecryptfs_writepage,
.readpage = ecryptfs_readpage,
.prepare_write = ecryptfs_prepare_write,
.commit_write = ecryptfs_commit_write,
.bmap = ecryptfs_bmap,
.sync_page = ecryptfs_sync_page,
};