[PATCH] eCryptfs: Generalize metadata read/write
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>
diff --git a/fs/ecryptfs/mmap.c b/fs/ecryptfs/mmap.c
index 0af3aa3..ba3650d 100644
--- a/fs/ecryptfs/mmap.c
+++ b/fs/ecryptfs/mmap.c
@@ -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 @@
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 @@
*
* 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 @@
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 @@
return rc;
}
+struct kmem_cache *ecryptfs_xattr_cache;
+
/**
* ecryptfs_commit_write
* @file: The eCryptfs file object
@@ -581,7 +659,6 @@
"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 @@
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: