eCryptfs: set up and destroy persistent lower file (4981e081) · Commits · jan.koester / Linux

fs/ecryptfs/inode.c

+19 −4

Original line number	Diff line number	Diff line
		@@ -119,11 +119,24 @@ 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");
		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);
		if (rc) {
		@@ -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"

fs/ecryptfs/main.c

+65 −0

Original line number	Diff line number	Diff line
		@@ -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;
		}

fs/ecryptfs/super.c

+19 −3

Original line number	Diff line number	Diff line
		@@ -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 @@ static struct inode ecryptfs_alloc_inode(struct super_block sb)
		* 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);
		}