2007-01-31 14:55:11

by Harry Papaxenopoulos

[permalink] [raw]
Subject: [Resubmit][PATCH 4/5] Secure Deletion and Trash-Bin Support for Ext4

Trash-Bin Functionality for the ext4 filesystem:

Signed-off-by: Harry Papaxenopoulos <[email protected]>
Signed-off-by: Nikolai Joukov <[email protected]>
Signed-off-by: Erez Zadok <[email protected]>

Index: sdfs/src/linux-2.6.20-rc6-trashbin/fs/ext4/super.c
===================================================================
--- sdfs.orig/src/linux-2.6.20-rc6-trashbin/fs/ext4/super.c
+++ sdfs/src/linux-2.6.20-rc6-trashbin/fs/ext4/super.c
@@ -35,6 +35,7 @@
#include <linux/namei.h>
#include <linux/quotaops.h>
#include <linux/seq_file.h>
+#include <linux/trashbin.h>

#include <asm/uaccess.h>

@@ -1846,6 +1847,11 @@ static int ext4_fill_super (struct super
goto failed_mount4;
}

+#ifdef CONFIG_EXT4DEV_FS_TRASHBIN
+ if ((sb->s_flags & MNT_TRASHBIN) && vfs_create_trash_bin(sb))
+ goto failed_mount4;
+#endif
+
ext4_setup_super (sb, es, sb->s_flags & MS_RDONLY);
/*
* akpm: core read_super() calls in here with the superblock locked.
Index: sdfs/src/linux-2.6.20-rc6-trashbin/fs/ext4/namei.c
===================================================================
--- sdfs.orig/src/linux-2.6.20-rc6-trashbin/fs/ext4/namei.c
+++ sdfs/src/linux-2.6.20-rc6-trashbin/fs/ext4/namei.c
@@ -37,6 +37,8 @@
#include <linux/buffer_head.h>
#include <linux/bio.h>
#include <linux/smp_lock.h>
+#include <linux/mount.h>
+#include <linux/trashbin.h>

#include "namei.h"
#include "xattr.h"
@@ -2077,6 +2079,10 @@ static int ext4_unlink(struct inode * di
struct buffer_head * bh;
struct ext4_dir_entry_2 * de;
handle_t *handle;
+ int trashed = 0;
+#ifdef CONFIG_EXT4DEV_FS_TRASHBIN
+ struct dentry *user_dentry = NULL;
+#endif

/* Initialize quotas before so that eventual writes go
* in separate transaction */
@@ -2105,13 +2111,41 @@ static int ext4_unlink(struct inode * di
inode->i_ino, inode->i_nlink);
inode->i_nlink = 1;
}
- retval = ext4_delete_entry(handle, dir, de, bh);
+#ifdef CONFIG_EXT4DEV_FS_TRASHBIN
+ if ((dentry->d_inode->i_sb->s_flags & MNT_TRASHBIN) &&
+ (EXT4_I(dentry->d_inode)->i_flags &
+ (EXT4_UNRM_FL | EXT4_SECRM_FL))) {
+
+ /*
+ * We put this code here to optimize the common case. Since
+ * lookups are expensive, we try to reserve from making any,
+ * unless one of the trash-bin flags are set. The cleanest
+ * way though is to probably move this code outside the
+ * above if statement.
+ */
+ user_dentry = vfs_get_user_dentry(dir, 1);
+ if (IS_ERR(user_dentry)) {
+ retval = PTR_ERR(user_dentry);
+ user_dentry = NULL;
+ goto end_unlink;
+ }
+
+ if (inode->i_nlink == 1 && user_dentry->d_inode &&
+ user_dentry->d_inode->i_ino != dir->i_ino) {
+ retval = vfs_trash_entry(dir, dentry);
+ trashed = 1;
+ }
+ }
+#endif
+ if (!trashed)
+ retval = ext4_delete_entry(handle, dir, de, bh);
if (retval)
goto end_unlink;
dir->i_ctime = dir->i_mtime = CURRENT_TIME_SEC;
ext4_update_dx_flag(dir);
ext4_mark_inode_dirty(handle, dir);
- drop_nlink(inode);
+ if (!trashed)
+ drop_nlink(inode);
if (!inode->i_nlink)
ext4_orphan_add(handle, inode);
inode->i_ctime = dir->i_ctime;
@@ -2121,6 +2155,10 @@ static int ext4_unlink(struct inode * di
end_unlink:
ext4_journal_stop(handle);
brelse (bh);
+#ifdef CONFIG_EXT4DEV_FS_TRASHBIN
+ if (user_dentry)
+ dput(user_dentry);
+#endif
return retval;
}

Index: sdfs/src/linux-2.6.20-rc6-trashbin/fs/Kconfig
===================================================================
--- sdfs.orig/src/linux-2.6.20-rc6-trashbin/fs/Kconfig
+++ sdfs/src/linux-2.6.20-rc6-trashbin/fs/Kconfig
@@ -227,6 +227,15 @@ config EXT4DEV_FS_SECURITY
If you are not using a security module that requires using
extended attributes for file security labels, say N.

+config EXT4DEV_FS_TRASHBIN
+ bool "Ext4 trashbin functionality"
+ depends on TRASHBIN
+ depends on EXT4DEV_FS
+ help
+ Trashbin functionality for the ext4 filesystem
+
+ If unsure, say N.
+
config JBD
tristate
help


2007-02-01 20:43:11

by Mingming Cao

[permalink] [raw]
Subject: Re: [Resubmit][PATCH 4/5] Secure Deletion and Trash-Bin Support for Ext4

On Wed, 2007-01-31 at 09:55 -0500, Harry Papaxenopoulos wrote:

> @@ -2077,6 +2079,10 @@ static int ext4_unlink(struct inode * di
> struct buffer_head * bh;
> struct ext4_dir_entry_2 * de;
> handle_t *handle;
> + int trashed = 0;
> +#ifdef CONFIG_EXT4DEV_FS_TRASHBIN
> + struct dentry *user_dentry = NULL;
> +#endif
>
> /* Initialize quotas before so that eventual writes go
> * in separate transaction */
> @@ -2105,13 +2111,41 @@ static int ext4_unlink(struct inode * di
> inode->i_ino, inode->i_nlink);
> inode->i_nlink = 1;
> }
> - retval = ext4_delete_entry(handle, dir, de, bh);
> +#ifdef CONFIG_EXT4DEV_FS_TRASHBIN
> + if ((dentry->d_inode->i_sb->s_flags & MNT_TRASHBIN) &&
> + (EXT4_I(dentry->d_inode)->i_flags &
> + (EXT4_UNRM_FL | EXT4_SECRM_FL))) {
> +
> + /*
> + * We put this code here to optimize the common case. Since
> + * lookups are expensive, we try to reserve from making any,
> + * unless one of the trash-bin flags are set. The cleanest
> + * way though is to probably move this code outside the
> + * above if statement.
> + */
> + user_dentry = vfs_get_user_dentry(dir, 1);
> + if (IS_ERR(user_dentry)) {
> + retval = PTR_ERR(user_dentry);
> + user_dentry = NULL;
> + goto end_unlink;
> + }
> +
> + if (inode->i_nlink == 1 && user_dentry->d_inode &&
> + user_dentry->d_inode->i_ino != dir->i_ino) {
> + retval = vfs_trash_entry(dir, dentry);
> + trashed = 1;
> + }
> + }
> +#endif
> + if (!trashed)
> + retval = ext4_delete_entry(handle, dir, de, bh);
> if (retval)
> goto end_unlink;
> dir->i_ctime = dir->i_mtime = CURRENT_TIME_SEC;
> ext4_update_dx_flag(dir);
> ext4_mark_inode_dirty(handle, dir);
> - drop_nlink(inode);
> + if (!trashed)
> + drop_nlink(inode);
> if (!inode->i_nlink)
> ext4_orphan_add(handle, inode);
> inode->i_ctime = dir->i_ctime;
> @@ -2121,6 +2155,10 @@ static int ext4_unlink(struct inode * di
> end_unlink:
> ext4_journal_stop(handle);
> brelse (bh);
> +#ifdef CONFIG_EXT4DEV_FS_TRASHBIN
> + if (user_dentry)
> + dput(user_dentry);
> +#endif
> return retval;
> }

I feel we could move the trash bin feature check at the beginning of
ext4_unlink() call, we don't need to start a journal and find the entry
at all if we are going to move that file to trash bin, that's all
handles by rename.

Mingming