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eCryptfs: set up and destroy persistent lower file 

This patch sets up and destroys the persistent lower file for each eCryptfs
inode.

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 2007-10-16 01:28:09 -07:00 committed by Linus Torvalds
parent 0216f7f792
commit 4981e081cf
3 changed files with 103 additions and 7 deletions
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23
fs/ecryptfs/inode.c
View File

@ -119,10 +119,23 @@ ecryptfs_do_create(struct inode *directory_inode,
}
rc = ecryptfs_create_underlying_file(lower_dir_dentry->d_inode,
ecryptfs_dentry, mode, nd);
if (unlikely(rc)) {
ecryptfs_printk(KERN_ERR,
"Failure to create underlying file\n");
goto out_lock;
if (rc) {
struct inode *ecryptfs_inode = ecryptfs_dentry->d_inode;
struct ecryptfs_inode_info *inode_info =
ecryptfs_inode_to_private(ecryptfs_inode);
printk(KERN_WARNING "%s: Error creating underlying file; "
"rc = [%d]; checking for existing\n", __FUNCTION__, rc);
if (inode_info) {
mutex_lock(&inode_info->lower_file_mutex);
if (!inode_info->lower_file) {
mutex_unlock(&inode_info->lower_file_mutex);
printk(KERN_ERR "%s: Failure to set underlying "
"file; rc = [%d]\n", __FUNCTION__, rc);
goto out_lock;
}
mutex_unlock(&inode_info->lower_file_mutex);
}
}
rc = ecryptfs_interpose(lower_dentry, ecryptfs_dentry,
directory_inode->i_sb, 0);
@ -252,6 +265,8 @@ ecryptfs_create(struct inode *directory_inode, struct dentry *ecryptfs_dentry,
{
int rc;
/* ecryptfs_do_create() calls ecryptfs_interpose(), which opens
* the crypt_stat->lower_file (persistent file) */
rc = ecryptfs_do_create(directory_inode, ecryptfs_dentry, mode, nd);
if (unlikely(rc)) {
ecryptfs_printk(KERN_WARNING, "Failed to create file in"

65
fs/ecryptfs/main.c
View File

@ -98,6 +98,64 @@ void __ecryptfs_printk(const char *fmt, ...)
va_end(args);
}
/**
* ecryptfs_init_persistent_file
* @ecryptfs_dentry: Fully initialized eCryptfs dentry object, with
* the lower dentry and the lower mount set
*
* eCryptfs only ever keeps a single open file for every lower
* inode. All I/O operations to the lower inode occur through that
* file. When the first eCryptfs dentry that interposes with the first
* lower dentry for that inode is created, this function creates the
* persistent file struct and associates it with the eCryptfs
* inode. When the eCryptfs inode is destroyed, the file is closed.
*
* The persistent file will be opened with read/write permissions, if
* possible. Otherwise, it is opened read-only.
*
* This function does nothing if a lower persistent file is already
* associated with the eCryptfs inode.
*
* Returns zero on success; non-zero otherwise
*/
int ecryptfs_init_persistent_file(struct dentry *ecryptfs_dentry)
{
struct ecryptfs_inode_info *inode_info =
ecryptfs_inode_to_private(ecryptfs_dentry->d_inode);
int rc = 0;
mutex_lock(&inode_info->lower_file_mutex);
if (!inode_info->lower_file) {
struct dentry *lower_dentry;
struct vfsmount *lower_mnt =
ecryptfs_dentry_to_lower_mnt(ecryptfs_dentry);
lower_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry);
/* Corresponding dput() and mntput() are done when the
* persistent file is fput() when the eCryptfs inode
* is destroyed. */
dget(lower_dentry);
mntget(lower_mnt);
inode_info->lower_file = dentry_open(lower_dentry,
lower_mnt,
(O_RDWR | O_LARGEFILE));
if (IS_ERR(inode_info->lower_file))
inode_info->lower_file = dentry_open(lower_dentry,
lower_mnt,
(O_RDONLY
| O_LARGEFILE));
if (IS_ERR(inode_info->lower_file)) {
printk(KERN_ERR "Error opening lower persistent file "
"for lower_dentry [0x%p] and lower_mnt [0x%p]\n",
lower_dentry, lower_mnt);
rc = PTR_ERR(inode_info->lower_file);
inode_info->lower_file = NULL;
}
}
mutex_unlock(&inode_info->lower_file_mutex);
return rc;
}
/**
* ecryptfs_interpose
* @lower_dentry: Existing dentry in the lower filesystem
@ -155,6 +213,13 @@ int ecryptfs_interpose(struct dentry *lower_dentry, struct dentry *dentry,
/* This size will be overwritten for real files w/ headers and
* other metadata */
fsstack_copy_inode_size(inode, lower_inode);
rc = ecryptfs_init_persistent_file(dentry);
if (rc) {
printk(KERN_ERR "%s: Error attempting to initialize the "
"persistent file for the dentry with name [%s]; "
"rc = [%d]\n", __FUNCTION__, dentry->d_name.name, rc);
goto out;
}
out:
return rc;
}

22
fs/ecryptfs/super.c
View File

@ -27,6 +27,7 @@
#include <linux/mount.h>
#include <linux/key.h>
#include <linux/seq_file.h>
#include <linux/file.h>
#include <linux/crypto.h>
#include "ecryptfs_kernel.h"
@ -63,9 +64,10 @@ out:
* ecryptfs_destroy_inode
* @inode: The ecryptfs inode
*
* This is used during the final destruction of the inode.
* All allocation of memory related to the inode, including allocated
* memory in the crypt_stat struct, will be released here.
* This is used during the final destruction of the inode. All
* allocation of memory related to the inode, including allocated
* memory in the crypt_stat struct, will be released here. This
* function also fput()'s the persistent file for the lower inode.
* There should be no chance that this deallocation will be missed.
*/
static void ecryptfs_destroy_inode(struct inode *inode)
@ -73,6 +75,20 @@ static void ecryptfs_destroy_inode(struct inode *inode)
struct ecryptfs_inode_info *inode_info;
inode_info = ecryptfs_inode_to_private(inode);
mutex_lock(&inode_info->lower_file_mutex);
if (inode_info->lower_file) {
struct dentry *lower_dentry =
inode_info->lower_file->f_dentry;
BUG_ON(!lower_dentry);
if (lower_dentry->d_inode) {
fput(inode_info->lower_file);
inode_info->lower_file = NULL;
d_drop(lower_dentry);
d_delete(lower_dentry);
}
}
mutex_unlock(&inode_info->lower_file_mutex);
ecryptfs_destroy_crypt_stat(&inode_info->crypt_stat);
kmem_cache_free(ecryptfs_inode_info_cache, inode_info);
}