Sent to stable: eCryptfs: Add getattr function

[Tim Gardner]

The following changes since commit 4b876bd4ad82fb8866fcf8724514c80ebc158f1d:
  Andy Whitcroft (1):
        UBUNTU: ensure we build the source package contents when enabled

are available in the git repository at:

  git://kernel.ubuntu.com/rtg/ubuntu-lucid.git lp390833

Tyler Hicks (1):
      eCryptfs: Add getattr function

 fs/ecryptfs/inode.c |   16 ++++++++++++++++
 1 files changed, 16 insertions(+), 0 deletions(-)

>From 546d6ff6604d15ae3997969ff2b35dc72b2b44e4 Mon Sep 17 00:00:00 2001
From: Tyler Hicks <tyhicks at linux.vnet.ibm.com>
Date: Wed, 4 Nov 2009 02:48:01 -0600
Subject: [PATCH] eCryptfs: Add getattr function
MIME-Version: 1.0
Content-Type: text/plain; charset=utf-8
Content-Transfer-Encoding: 8bit

The i_blocks field of an eCryptfs inode cannot be trusted, but
generic_fillattr() uses it to instantiate the blocks field of a stat()
syscall when a filesystem doesn't implement its own getattr().  Users
have noticed that the output of du is incorrect on newly created files.

This patch creates ecryptfs_getattr() which calls into the lower
filesystem's getattr() so that eCryptfs can use its kstat.blocks value
after calling generic_fillattr().  It is important to note that the
block count includes the eCryptfs metadata stored in the beginning of
the lower file plus any padding used to fill an extent before
encryption.

BugLink: http://bugs.launchpad.net/bugs/390833

Reported-by: Dominic Sacré <dominic.sacre at gmx.de>
Signed-off-by: Tyler Hicks <tyhicks at linux.vnet.ibm.com>
(cherry picked from commit f8f484d1b6677dd5cd5e7e605db747e8c30bbd47)

Signed-off-by: Tim Gardner <tim.gardner at canonical.com>
---
 fs/ecryptfs/inode.c |   16 ++++++++++++++++
 1 files changed, 16 insertions(+), 0 deletions(-)

diff --git a/fs/ecryptfs/inode.c b/fs/ecryptfs/inode.c
index 056fed6..728f07e 100644
--- a/fs/ecryptfs/inode.c
+++ b/fs/ecryptfs/inode.c
@@ -971,6 +971,21 @@ out:
 	return rc;
 }
 
+int ecryptfs_getattr(struct vfsmount *mnt, struct dentry *dentry,
+		     struct kstat *stat)
+{
+	struct kstat lower_stat;
+	int rc;
+
+	rc = vfs_getattr(ecryptfs_dentry_to_lower_mnt(dentry),
+			 ecryptfs_dentry_to_lower(dentry), &lower_stat);
+	if (!rc) {
+		generic_fillattr(dentry->d_inode, stat);
+		stat->blocks = lower_stat.blocks;
+	}
+	return rc;
+}
+
 int
 ecryptfs_setxattr(struct dentry *dentry, const char *name, const void *value,
 		  size_t size, int flags)
@@ -1100,6 +1115,7 @@ const struct inode_operations ecryptfs_dir_iops = {
 const struct inode_operations ecryptfs_main_iops = {
 	.permission = ecryptfs_permission,
 	.setattr = ecryptfs_setattr,
+	.getattr = ecryptfs_getattr,
 	.setxattr = ecryptfs_setxattr,
 	.getxattr = ecryptfs_getxattr,
 	.listxattr = ecryptfs_listxattr,
-- 
1.6.2.4