[PATCH 10/13: eCryptfs] Mmap operations

Phillip Hellewell
2006-05-13T03:47:11Z

This is the 10th patch in a series of 13 constituting the kernel
components of the eCryptfs cryptographic filesystem.

eCryptfs mmap operations. Page read/write code works closely with
encryption/decryption routines in crypto.c.

Signed-off-by: Phillip Hellewell <phillip@hellewell.homeip.net>
Signed-off-by: Michael Halcrow <mhalcrow@us.ibm.com>

---

mmap.c | 796 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
1 files changed, 796 insertions(+)

Index: linux-2.6.17-rc3-mm1-ecryptfs/fs/ecryptfs/mmap.c
===================================================================
--- /dev/null 1970-01-01 00:00:00.000000000 +0000
+++ linux-2.6.17-rc3-mm1-ecryptfs/fs/ecryptfs/mmap.c 2006-05-12 20:00:29.000000000 -0600
@@ -0,0 +1,796 @@
+/**
+ * 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) 2004-2006 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 <asm/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 page *page;
+ struct dentry *dentry;
+ struct inode *inode;
+ struct address_space *mapping;
+
+ dentry = file->f_dentry;
+ inode = dentry->d_inode;
+ mapping = inode->i_mapping;
+ page = read_cache_page(mapping, index,
+ (filler_t *)mapping->a_ops->readpage,
+ (void *)file);
+ if (IS_ERR(page))
+ goto out;
+ wait_on_page_locked(page);
+out:
+ return page;
+}
+
+static
+int write_zeros(struct file *file, pgoff_t index, int start, int num_zeros);
+
+/**
+ * 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_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 = 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, "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 = 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, "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 = write_zeros(file, index, 0, PAGE_CACHE_SIZE);
+ if (rc) {
+ ecryptfs_printk(KERN_ERR, "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 = write_zeros(file, index, 0, (new_end_pos_in_page + 1));
+ if (rc) {
+ ecryptfs_printk(KERN_ERR, "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;
+ struct address_space_operations *lower_a_ops;
+
+ dentry = file->f_dentry;
+ if (!ecryptfs_file_to_private(file)) {
+ rc = -ENOENT;
+ ecryptfs_printk(KERN_ERR, "No lower file info\n");
+ goto out;
+ }
+ 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;
+ }
+ wait_on_page_locked(lower_page);
+ page_data = (char *)kmap(page);
+ if (!page_data) {
+ rc = -ENOMEM;
+ ecryptfs_printk(KERN_ERR, "Error mapping page\n");
+ goto out;
+ }
+ lower_page_data = (char *)kmap(lower_page);
+ if (!lower_page_data) {
+ rc = -ENOMEM;
+ ecryptfs_printk(KERN_ERR, "Error mapping page\n");
+ kunmap(page);
+ goto out;
+ }
+ memcpy(page_data, lower_page_data, PAGE_CACHE_SIZE);
+ kunmap(lower_page);
+ kunmap(page);
+ rc = 0;
+out:
+ if (likely(lower_page))
+ page_cache_release(lower_page);
+ if (rc == 0)
+ SetPageUptodate(page);
+ else
+ ClearPageUptodate(page);
+ return rc;
+}
+
+/**
+ * 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;
+
+ ASSERT(file && file->f_dentry && file->f_dentry->d_inode);
+ crypt_stat =
+ &ecryptfs_inode_to_private(file->f_dentry->d_inode)->crypt_stat;
+ if (!crypt_stat
+ || !ECRYPTFS_CHECK_FLAG(crypt_stat->flags, ECRYPTFS_ENCRYPTED)
+ || ECRYPTFS_CHECK_FLAG(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 {
+ 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;
+}
+
+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;
+ int rc = 0;
+ char *page_virt;
+
+ if ((i_size_read(inode) / PAGE_CACHE_SIZE) == page->index) {
+ end_byte_in_page = i_size_read(inode) % PAGE_CACHE_SIZE;
+ if (to > end_byte_in_page)
+ end_byte_in_page = to;
+ page_virt = kmap(page);
+ if (!page_virt) {
+ rc = -ENOMEM;
+ ecryptfs_printk(KERN_WARNING,
+ "Could not map page\n");
+ goto out;
+ }
+ memset((page_virt + end_byte_in_page), 0,
+ (PAGE_CACHE_SIZE - end_byte_in_page));
+ kunmap(page);
+ }
+out:
+ return rc;
+}
+
+static int ecryptfs_prepare_write(struct file *file, struct page *page,
+ unsigned from, unsigned to)
+{
+ int rc = 0;
+
+ kmap(page);
+ 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;
+}
+
+int ecryptfs_grab_and_map_lower_page(struct page **lower_page,
+ char **lower_virt,
+ struct inode *lower_inode,
+ unsigned long lower_page_index)
+{
+ int rc = 0;
+
+ (*lower_page) = grab_cache_page(lower_inode->i_mapping,
+ lower_page_index);
+ if (!(*lower_page)) {
+ ecryptfs_printk(KERN_ERR, "grab_cache_page for "
+ "lower_page_index = [0x%.16x] failed\n",
+ lower_page_index);
+ rc = -EINVAL;
+ goto out;
+ }
+ if (lower_virt)
+ (*lower_virt) = kmap((*lower_page));
+ else
+ kmap((*lower_page));
+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;
+}
+
+void ecryptfs_unmap_and_release_lower_page(struct page *lower_page)
+{
+ kunmap(lower_page);
+ ecryptfs_printk(KERN_DEBUG, "Unlocking lower page with index = "
+ "[0x%.16x]\n", lower_page->index);
+ 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.
+ */
+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;
+ struct address_space_operations *lower_a_ops;
+ u64 file_size;
+
+ rc = ecryptfs_grab_and_map_lower_page(&header_page, &header_virt,
+ lower_inode, 0);
+ if (rc) {
+ ecryptfs_printk(KERN_ERR, "grab_cache_page for header page "
+ "failed\n");
+ goto out;
+ }
+ lower_a_ops = lower_inode->i_mapping->a_ops;
+ rc = lower_a_ops->prepare_write(lower_file, header_page, 0, 8);
+ 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);
+ memcpy(header_virt, &file_size, sizeof(u64));
+ 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");
+ ecryptfs_unmap_and_release_lower_page(header_page);
+ lower_inode->i_mtime = lower_inode->i_ctime = CURRENT_TIME;
+ mark_inode_dirty_sync(inode);
+out:
+ return rc;
+}
+
+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;
+
+ rc = ecryptfs_grab_and_map_lower_page(lower_page, NULL, lower_inode,
+ lower_page_index);
+ if (rc) {
+ ecryptfs_printk(KERN_ERR, "Error attempting to grab and map "
+ "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) {
+ ecryptfs_printk(KERN_ERR, "prepare_write for "
+ "lower_page_index = [0x%.16x] failed; rc = "
+ "[%d]\n", lower_page_index, rc);
+ }
+out:
+ if (rc && (*lower_page)) {
+ ecryptfs_unmap_and_release_lower_page(*lower_page);
+ (*lower_page) = NULL;
+ }
+ 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 rc = 0;
+
+ rc = lower_inode->i_mapping->a_ops->commit_write(
+ lower_file, lower_page, byte_offset, region_size);
+ if (rc < 0) {
+ ecryptfs_printk(KERN_ERR,
+ "Error committing write; rc = [%d]\n", rc);
+ } else
+ rc = 0;
+ ecryptfs_unmap_and_release_lower_page(lower_page);
+ 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;
+}
+
+static int
+process_new_file(struct ecryptfs_crypt_stat *crypt_stat,
+ struct file *file, struct inode *inode)
+{
+ struct page *header_page;
+ struct address_space_operations *lower_a_ops;
+ struct inode *lower_inode;
+ struct file *lower_file;
+ char *header_virt;
+ int rc = 0;
+ int current_header_page = 0;
+ int header_pages;
+ int more_header_data_to_be_written = 1;
+
+ lower_inode = ecryptfs_inode_to_lower(inode);
+ lower_file = ecryptfs_file_to_lower(file);
+ lower_a_ops = lower_inode->i_mapping->a_ops;
+ header_pages = ((crypt_stat->header_extent_size
+ * crypt_stat->num_header_extents_at_front)
+ / PAGE_CACHE_SIZE);
+ ASSERT(header_pages >= 1);
+ while (current_header_page < header_pages) {
+ rc = ecryptfs_grab_and_map_lower_page(&header_page,
+ &header_virt,
+ lower_inode,
+ current_header_page);
+ if (rc) {
+ ecryptfs_printk(KERN_ERR, "grab_cache_page for "
+ "header page [%d] failed; rc = [%d]\n",
+ current_header_page, rc);
+ goto out;
+ }
+ rc = lower_a_ops->prepare_write(lower_file, header_page, 0,
+ PAGE_CACHE_SIZE);
+ if (rc) {
+ ecryptfs_printk(KERN_ERR, "Error preparing to write "
+ "header page out; rc = [%d]\n", rc);
+ goto out;
+ }
+ memset(header_virt, 0, PAGE_CACHE_SIZE);
+ if (more_header_data_to_be_written) {
+ rc = ecryptfs_write_headers_virt(header_virt,
+ crypt_stat,
+ file->f_dentry);
+ if (rc) {
+ ecryptfs_printk(KERN_WARNING, "Error "
+ "generating header; rc = "
+ "[%d]\n", rc);
+ rc = -EIO;
+ memset(header_virt, 0, PAGE_CACHE_SIZE);
+ ecryptfs_unmap_and_release_lower_page(
+ header_page);
+ goto out;
+ }
+ if (current_header_page == 0)
+ memset(header_virt, 0, 8);
+ more_header_data_to_be_written = 0;
+ }
+ rc = lower_a_ops->commit_write(lower_file, header_page, 0,
+ PAGE_CACHE_SIZE);
+ ecryptfs_unmap_and_release_lower_page(header_page);
+ if (rc < 0) {
+ ecryptfs_printk(KERN_ERR,
+ "Error commiting header page write; "
+ "rc = [%d]\n", rc);
+ break;
+ }
+ current_header_page++;
+ }
+ if (rc >= 0) {
+ rc = 0;
+ ecryptfs_printk(KERN_DEBUG, "lower_inode->i_blocks = "
+ "[0x%.16x]\n", lower_inode->i_blocks);
+ i_size_write(inode, 0);
+ lower_inode->i_mtime = lower_inode->i_ctime = CURRENT_TIME;
+ mark_inode_dirty_sync(inode);
+ }
+ ecryptfs_printk(KERN_DEBUG, "Clearing ECRYPTFS_NEW_FILE flag in "
+ "crypt_stat at memory location [%p]\n", crypt_stat);
+ ECRYPTFS_CLEAR_FLAG(crypt_stat->flags, ECRYPTFS_NEW_FILE);
+out:
+ return rc;
+}
+
+/**
+ * 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;
+ unsigned bytes = to - from;
+ 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_dentry->d_inode)->crypt_stat;
+ ASSERT(crypt_stat);
+ ASSERT(lower_file);
+ if (ECRYPTFS_CHECK_FLAG(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);
+ rc = process_new_file(crypt_stat, file, inode);
+ if (rc) {
+ ecryptfs_printk(KERN_ERR, "Error processing new "
+ "file; rc = [%d]\n", rc);
+ goto out;
+ }
+ } 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;
+ }
+ rc = bytes;
+ 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));
+ }
+ ecryptfs_write_inode_size_to_header(lower_file, lower_inode, inode);
+ lower_inode->i_mtime = lower_inode->i_ctime = CURRENT_TIME;
+ mark_inode_dirty_sync(inode);
+out:
+ kunmap(page); /* mapped in prior call (prepare_write) */
+ if (rc < 0)
+ ClearPageUptodate(page);
+ else
+ SetPageUptodate(page);
+ mutex_unlock(&lower_inode->i_mutex);
+ return rc;
+}
+
+/**
+ * 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
+ */
+static
+int 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;
+ }
+ kmap(tmp_page);
+ rc = ecryptfs_prepare_write(file, tmp_page, start, start + num_zeros);
+ if (rc) {
+ ecryptfs_printk(KERN_ERR, "Error preparing to write zero's "
+ "to remainder of page at index [0x%.16x]\n",
+ index);
+ kunmap(tmp_page);
+ page_cache_release(tmp_page);
+ goto out;
+ }
+ memset(((char *)page_address(tmp_page) + start), 0, num_zeros);
+ 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);
+ kunmap(tmp_page);
+ page_cache_release(tmp_page);
+ goto out;
+ }
+ rc = 0;
+ kunmap(tmp_page);
+ 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_get_page(lower_inode->i_mapping, page->index);
+ if (!lower_page) {
+ ecryptfs_printk(KERN_DEBUG, "find_get_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,
+};