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[PATCH] eCryptfs: Generalize metadata read/write

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Generalize the metadata reading and writing mechanisms, with two targets for
now: metadata in file header and metadata in the user.ecryptfs xattr of the
lower file.

[akpm@osdl.org: printk warning fix]
[bunk@stusta.de: make some needlessly global code static]
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>
This commit is contained in:
Michael Halcrow
2007-02-12 00:53:46 -08:00
committed by Linus Torvalds
parent 17398957aa
commit dd2a3b7ad9
7 changed files with 348 additions and 146 deletions
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96
fs/ecryptfs/mmap.c
View File

@@ -6,7 +6,7 @@
*
* Copyright (C) 1997-2003 Erez Zadok
* Copyright (C) 2001-2003 Stony Brook University
* Copyright (C) 2004-2006 International Business Machines Corp.
* 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
@@ -308,6 +308,9 @@ out:
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;
@@ -407,10 +410,9 @@ static void ecryptfs_unmap_and_release_lower_page(struct page *lower_page)
*
* 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)
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;
@@ -442,6 +444,80 @@ 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) {
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,
@@ -528,6 +604,8 @@ out:
return rc;
}
struct kmem_cache *ecryptfs_xattr_cache;
/**
* ecryptfs_commit_write
* @file: The eCryptfs file object
@@ -581,7 +659,6 @@ static int ecryptfs_commit_write(struct file *file, struct page *page,
"index [0x%.16x])\n", page->index);
goto out;
}
rc = 0;
inode->i_blocks = lower_inode->i_blocks;
pos = (page->index << PAGE_CACHE_SHIFT) + to;
if (pos > i_size_read(inode)) {
@@ -589,7 +666,12 @@ static int ecryptfs_commit_write(struct file *file, struct page *page,
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);
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: