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Message-ID: <20070917215016.GP13679@halcrow.austin.ibm.com>
Date: Mon, 17 Sep 2007 16:50:16 -0500
From: Michael Halcrow <mhalcrow@...ibm.com>
To: akpm@...ux-foundation.org
Cc: linux-kernel@...r.kernel.org, linux-fsdevel@...r.kernel.org,
ecryptfs-devel@...ts.sourceforge.net
Subject: [PATCH 8/11] eCryptfs: Convert mmap functions to use persistent file
Convert readpage, prepare_write, and commit_write to use read_write.c
routines. Remove sync_page; I cannot think of a good reason for
implementing that in eCryptfs.
Signed-off-by: Michael Halcrow <mhalcrow@...ibm.com>
---
fs/ecryptfs/mmap.c | 199 +++++++++++++++++++++++++++-------------------------
1 files changed, 103 insertions(+), 96 deletions(-)
diff --git a/fs/ecryptfs/mmap.c b/fs/ecryptfs/mmap.c
index 60e635e..dd68dd3 100644
--- a/fs/ecryptfs/mmap.c
+++ b/fs/ecryptfs/mmap.c
@@ -267,9 +267,78 @@ static void set_header_info(char *page_virt,
}
/**
+ * ecryptfs_copy_up_encrypted_with_header
+ * @page: Sort of a ``virtual'' representation of the encrypted lower
+ * file. The actual lower file does not have the metadata in
+ * the header.
+ * @crypt_stat: The eCryptfs inode's cryptographic context
+ *
+ * The ``view'' is the version of the file that userspace winds up
+ * seeing, with the header information inserted.
+ */
+static int
+ecryptfs_copy_up_encrypted_with_header(struct page *page,
+ struct ecryptfs_crypt_stat *crypt_stat)
+{
+ loff_t extent_num_in_page = 0;
+ loff_t num_extents_per_page = (PAGE_CACHE_SIZE
+ / crypt_stat->extent_size);
+ int rc = 0;
+
+ while (extent_num_in_page < num_extents_per_page) {
+ loff_t view_extent_num = ((page->index * num_extents_per_page)
+ + extent_num_in_page);
+
+ if (view_extent_num < crypt_stat->num_header_extents_at_front) {
+ /* This is a header extent */
+ char *page_virt;
+
+ page_virt = kmap_atomic(page, KM_USER0);
+ memset(page_virt, 0, PAGE_CACHE_SIZE);
+ /* TODO: Support more than one header extent */
+ if (view_extent_num == 0) {
+ rc = ecryptfs_read_xattr_region(
+ page_virt, page->mapping->host);
+ set_header_info(page_virt, crypt_stat);
+ }
+ kunmap_atomic(page_virt, KM_USER0);
+ flush_dcache_page(page);
+ if (rc) {
+ ClearPageUptodate(page);
+ printk(KERN_ERR "%s: Error reading xattr "
+ "region; rc = [%d]\n", __FUNCTION__, rc);
+ goto out;
+ }
+ SetPageUptodate(page);
+ } else {
+ /* This is an encrypted data extent */
+ loff_t lower_offset =
+ ((view_extent_num -
+ crypt_stat->num_header_extents_at_front)
+ * crypt_stat->extent_size);
+
+ rc = ecryptfs_read_lower_page_segment(
+ page, (lower_offset >> PAGE_CACHE_SHIFT),
+ (lower_offset & ~PAGE_CACHE_MASK),
+ crypt_stat->extent_size, page->mapping->host);
+ if (rc) {
+ printk(KERN_ERR "%s: Error attempting to read "
+ "extent at offset [%lld] in the lower "
+ "file; rc = [%d]\n", __FUNCTION__,
+ lower_offset, rc);
+ goto out;
+ }
+ }
+ extent_num_in_page++;
+ }
+out:
+ return rc;
+}
+
+/**
* ecryptfs_readpage
- * @file: This is an ecryptfs file
- * @page: ecryptfs associated page to stick the read data into
+ * @file: An eCryptfs file
+ * @page: Page from eCryptfs inode mapping into which to stick the read data
*
* Read in a page, decrypting if necessary.
*
@@ -277,59 +346,35 @@ static void set_header_info(char *page_virt,
*/
static int ecryptfs_readpage(struct file *file, struct page *page)
{
+ struct ecryptfs_crypt_stat *crypt_stat =
+ &ecryptfs_inode_to_private(file->f_path.dentry->d_inode)->crypt_stat;
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;
- }
+ rc = ecryptfs_read_lower_page_segment(page, page->index, 0,
+ PAGE_CACHE_SIZE,
+ page->mapping->host);
} 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->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, page->mapping->host);
- 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;
- }
+ rc = ecryptfs_copy_up_encrypted_with_header(page,
+ crypt_stat);
+ if (rc) {
+ printk(KERN_ERR "%s: Error attempting to copy "
+ "the encrypted content from the lower "
+ "file whilst inserting the metadata "
+ "from the xattr into the header; rc = "
+ "[%d]\n", __FUNCTION__, rc);
+ goto out;
}
+
} else {
- rc = ecryptfs_do_readpage(file, page, page->index);
+ rc = ecryptfs_read_lower_page_segment(
+ page, page->index, 0, PAGE_CACHE_SIZE,
+ page->mapping->host);
if (rc) {
printk(KERN_ERR "Error reading page; rc = "
"[%d]\n", rc);
@@ -344,10 +389,7 @@ static int ecryptfs_readpage(struct file *file, struct page *page)
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);
@@ -403,9 +445,12 @@ static int ecryptfs_prepare_write(struct file *file, struct page *page,
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);
+ rc = ecryptfs_read_lower_page_segment(page, page->index, 0,
+ PAGE_CACHE_SIZE,
+ page->mapping->host);
if (page->index != 0) {
- loff_t end_of_prev_pg_pos = page_offset(page) - 1;
+ 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,
@@ -633,18 +678,11 @@ static int ecryptfs_commit_write(struct file *file, struct page *page,
unsigned from, unsigned to)
{
loff_t pos;
- struct inode *inode;
- struct inode *lower_inode;
- struct file *lower_file;
- struct ecryptfs_crypt_stat *crypt_stat;
+ struct inode *ecryptfs_inode = page->mapping->host;
+ struct ecryptfs_crypt_stat *crypt_stat =
+ &ecryptfs_inode_to_private(file->f_path.dentry->d_inode)->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);
@@ -654,6 +692,7 @@ static int ecryptfs_commit_write(struct file *file, struct page *page,
ecryptfs_printk(KERN_DEBUG, "Calling fill_zeros_to_end_of_page"
"(page w/ index = [0x%.16x], to = [%d])\n", page->index,
to);
+ /* Fills in zeros if 'to' goes beyond inode size */
rc = fill_zeros_to_end_of_page(page, to);
if (rc) {
ecryptfs_printk(KERN_WARNING, "Error attempting to fill "
@@ -667,25 +706,17 @@ static int ecryptfs_commit_write(struct file *file, struct page *page,
"index [0x%.16x])\n", page->index);
goto out;
}
- inode->i_blocks = lower_inode->i_blocks;
- pos = page_offset(page) + to;
- if (pos > i_size_read(inode)) {
- i_size_write(inode, pos);
+ pos = (page->index << PAGE_CACHE_SHIFT) + to;
+ if (pos > i_size_read(ecryptfs_inode)) {
+ i_size_write(ecryptfs_inode, pos);
ecryptfs_printk(KERN_DEBUG, "Expanded file size to "
- "[0x%.16x]\n", i_size_read(inode));
+ "[0x%.16x]\n", i_size_read(ecryptfs_inode));
}
- rc = ecryptfs_write_inode_size_to_metadata(inode);
+ rc = ecryptfs_write_inode_size_to_metadata(ecryptfs_inode);
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;
}
@@ -751,34 +782,10 @@ static sector_t ecryptfs_bmap(struct address_space *mapping, sector_t 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;
- }
- if (lower_page->mapping->a_ops->sync_page)
- 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,
};
--
1.5.1.6
-
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