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![Johannes Weiner](/assets/img/avatar_default.png)
Reclaim will be leaving shadow entries in the page cache radix tree upon evicting the real page. As those pages are found from the LRU, an iput() can lead to the inode being freed concurrently. At this point, reclaim must no longer install shadow pages because the inode freeing code needs to ensure the page tree is really empty. Add an address_space flag, AS_EXITING, that the inode freeing code sets under the tree lock before doing the final truncate. Reclaim will check for this flag before installing shadow pages. Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Reviewed-by: Rik van Riel <riel@redhat.com> Reviewed-by: Minchan Kim <minchan@kernel.org> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Bob Liu <bob.liu@oracle.com> Cc: Christoph Hellwig <hch@infradead.org> Cc: Dave Chinner <david@fromorbit.com> Cc: Greg Thelen <gthelen@google.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jan Kara <jack@suse.cz> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Luigi Semenzato <semenzato@google.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Metin Doslu <metin@citusdata.com> Cc: Michel Lespinasse <walken@google.com> Cc: Ozgun Erdogan <ozgun@citusdata.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Roman Gushchin <klamm@yandex-team.ru> Cc: Ryan Mallon <rmallon@gmail.com> Cc: Tejun Heo <tj@kernel.org> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
191 lines
6 KiB
C
191 lines
6 KiB
C
/**
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* eCryptfs: Linux filesystem encryption layer
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*
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* Copyright (C) 1997-2003 Erez Zadok
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* Copyright (C) 2001-2003 Stony Brook University
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* Copyright (C) 2004-2006 International Business Machines Corp.
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* Author(s): Michael A. Halcrow <mahalcro@us.ibm.com>
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* Michael C. Thompson <mcthomps@us.ibm.com>
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation; either version 2 of the
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* License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
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* 02111-1307, USA.
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*/
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#include <linux/fs.h>
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#include <linux/mount.h>
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#include <linux/key.h>
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#include <linux/slab.h>
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#include <linux/seq_file.h>
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#include <linux/file.h>
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#include <linux/crypto.h>
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#include <linux/statfs.h>
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#include <linux/magic.h>
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#include "ecryptfs_kernel.h"
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struct kmem_cache *ecryptfs_inode_info_cache;
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/**
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* ecryptfs_alloc_inode - allocate an ecryptfs inode
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* @sb: Pointer to the ecryptfs super block
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*
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* Called to bring an inode into existence.
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*
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* Only handle allocation, setting up structures should be done in
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* ecryptfs_read_inode. This is because the kernel, between now and
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* then, will 0 out the private data pointer.
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*
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* Returns a pointer to a newly allocated inode, NULL otherwise
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*/
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static struct inode *ecryptfs_alloc_inode(struct super_block *sb)
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{
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struct ecryptfs_inode_info *inode_info;
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struct inode *inode = NULL;
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inode_info = kmem_cache_alloc(ecryptfs_inode_info_cache, GFP_KERNEL);
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if (unlikely(!inode_info))
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goto out;
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ecryptfs_init_crypt_stat(&inode_info->crypt_stat);
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mutex_init(&inode_info->lower_file_mutex);
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atomic_set(&inode_info->lower_file_count, 0);
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inode_info->lower_file = NULL;
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inode = &inode_info->vfs_inode;
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out:
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return inode;
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}
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static void ecryptfs_i_callback(struct rcu_head *head)
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{
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struct inode *inode = container_of(head, struct inode, i_rcu);
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struct ecryptfs_inode_info *inode_info;
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inode_info = ecryptfs_inode_to_private(inode);
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kmem_cache_free(ecryptfs_inode_info_cache, inode_info);
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}
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/**
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* ecryptfs_destroy_inode
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* @inode: The ecryptfs inode
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*
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* This is used during the final destruction of the inode. All
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* allocation of memory related to the inode, including allocated
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* memory in the crypt_stat struct, will be released here.
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* There should be no chance that this deallocation will be missed.
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*/
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static void ecryptfs_destroy_inode(struct inode *inode)
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{
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struct ecryptfs_inode_info *inode_info;
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inode_info = ecryptfs_inode_to_private(inode);
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BUG_ON(inode_info->lower_file);
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ecryptfs_destroy_crypt_stat(&inode_info->crypt_stat);
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call_rcu(&inode->i_rcu, ecryptfs_i_callback);
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}
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/**
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* ecryptfs_statfs
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* @sb: The ecryptfs super block
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* @buf: The struct kstatfs to fill in with stats
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*
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* Get the filesystem statistics. Currently, we let this pass right through
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* to the lower filesystem and take no action ourselves.
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*/
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static int ecryptfs_statfs(struct dentry *dentry, struct kstatfs *buf)
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{
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struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
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int rc;
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if (!lower_dentry->d_sb->s_op->statfs)
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return -ENOSYS;
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rc = lower_dentry->d_sb->s_op->statfs(lower_dentry, buf);
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if (rc)
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return rc;
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buf->f_type = ECRYPTFS_SUPER_MAGIC;
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rc = ecryptfs_set_f_namelen(&buf->f_namelen, buf->f_namelen,
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&ecryptfs_superblock_to_private(dentry->d_sb)->mount_crypt_stat);
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return rc;
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}
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/**
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* ecryptfs_evict_inode
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* @inode - The ecryptfs inode
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*
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* Called by iput() when the inode reference count reached zero
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* and the inode is not hashed anywhere. Used to clear anything
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* that needs to be, before the inode is completely destroyed and put
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* on the inode free list. We use this to drop out reference to the
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* lower inode.
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*/
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static void ecryptfs_evict_inode(struct inode *inode)
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{
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truncate_inode_pages_final(&inode->i_data);
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clear_inode(inode);
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iput(ecryptfs_inode_to_lower(inode));
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}
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/**
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* ecryptfs_show_options
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*
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* Prints the mount options for a given superblock.
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* Returns zero; does not fail.
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*/
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static int ecryptfs_show_options(struct seq_file *m, struct dentry *root)
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{
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struct super_block *sb = root->d_sb;
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struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
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&ecryptfs_superblock_to_private(sb)->mount_crypt_stat;
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struct ecryptfs_global_auth_tok *walker;
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mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex);
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list_for_each_entry(walker,
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&mount_crypt_stat->global_auth_tok_list,
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mount_crypt_stat_list) {
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if (walker->flags & ECRYPTFS_AUTH_TOK_FNEK)
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seq_printf(m, ",ecryptfs_fnek_sig=%s", walker->sig);
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else
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seq_printf(m, ",ecryptfs_sig=%s", walker->sig);
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}
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mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex);
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seq_printf(m, ",ecryptfs_cipher=%s",
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mount_crypt_stat->global_default_cipher_name);
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if (mount_crypt_stat->global_default_cipher_key_size)
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seq_printf(m, ",ecryptfs_key_bytes=%zd",
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mount_crypt_stat->global_default_cipher_key_size);
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if (mount_crypt_stat->flags & ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED)
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seq_printf(m, ",ecryptfs_passthrough");
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if (mount_crypt_stat->flags & ECRYPTFS_XATTR_METADATA_ENABLED)
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seq_printf(m, ",ecryptfs_xattr_metadata");
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if (mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED)
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seq_printf(m, ",ecryptfs_encrypted_view");
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if (mount_crypt_stat->flags & ECRYPTFS_UNLINK_SIGS)
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seq_printf(m, ",ecryptfs_unlink_sigs");
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if (mount_crypt_stat->flags & ECRYPTFS_GLOBAL_MOUNT_AUTH_TOK_ONLY)
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seq_printf(m, ",ecryptfs_mount_auth_tok_only");
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return 0;
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}
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const struct super_operations ecryptfs_sops = {
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.alloc_inode = ecryptfs_alloc_inode,
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.destroy_inode = ecryptfs_destroy_inode,
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.statfs = ecryptfs_statfs,
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.remount_fs = NULL,
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.evict_inode = ecryptfs_evict_inode,
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.show_options = ecryptfs_show_options
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};
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