Fixes a regression caused by 21edad32205e97dc7ccb81a85234c77e760364c8

When file name encryption was enabled, ecryptfs_lookup() failed to use
the encrypted and encoded version of the upper, plaintext, file name
when performing a lookup in the lower file system. This made it
impossible to lookup existing encrypted file names and any newly created
files would have plaintext file names in the lower file system.

https://bugs.launchpad.net/ecryptfs/+bug/623087

Signed-off-by: Tyler Hicks <tyhicks@linux.vnet.ibm.com>

Some ecryptfs init functions are not prefixed by __init and thus not
freed after initialization. This patch saved about 1kB in ecryptfs
module.

Signed-off-by: Jerome Marchand <jmarchan@redhat.com>
Signed-off-by: Tyler Hicks <tyhicks@linux.vnet.ibm.com>

In this code, 0 is returned on memory allocation failure, even though other
failures return -ENOMEM or other similar values.

A simplified version of the semantic match that finds this problem is as
follows: (http://coccinelle.lip6.fr/)

// <smpl>
@@
expression ret;
expression x,e1,e2,e3;
@@

ret = 0
... when != ret = e1
*x = \(kmalloc\|kcalloc\|kzalloc\)(...)
... when != ret = e2
if (x == NULL) { ... when != ret = e3
  return ret;
}
// </smpl>

Signed-off-by: Julia Lawall <julia@diku.dk>
Signed-off-by: Tyler Hicks <tyhicks@linux.vnet.ibm.com>

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ecryptfs/ecryptfs-2.6:
  ecryptfs: dont call lookup_one_len to avoid NULL nameidata
  fs/ecryptfs/file.c: introduce missing free
  ecryptfs: release reference to lower mount if interpose fails
  eCryptfs: Handle ioctl calls with unlocked and compat functions
  ecryptfs: Fix warning in ecryptfs_process_response()

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6: (96 commits)
  no need for list_for_each_entry_safe()/resetting with superblock list
  Fix sget() race with failing mount
  vfs: don't hold s_umount over close_bdev_exclusive() call
  sysv: do not mark superblock dirty on remount
  sysv: do not mark superblock dirty on mount
  btrfs: remove junk sb_dirt change
  BFS: clean up the superblock usage
  AFFS: wait for sb synchronization when needed
  AFFS: clean up dirty flag usage
  cifs: truncate fallout
  mbcache: fix shrinker function return value
  mbcache: Remove unused features
  add f_flags to struct statfs(64)
  pass a struct path to vfs_statfs
  update VFS documentation for method changes.
  All filesystems that need invalidate_inode_buffers() are doing that explicitly
  convert remaining ->clear_inode() to ->evict_inode()
  Make ->drop_inode() just return whether inode needs to be dropped
  fs/inode.c:clear_inode() is gone
  fs/inode.c:evict() doesn't care about delete vs. non-delete paths now
  ...

Fix up trivial conflicts in fs/nilfs2/super.c

We'll need the path to implement the flags field for statvfs support.
We do have it available in all callers except:

 - ecryptfs_statfs.  This one doesn't actually need vfs_statfs but just
   needs to do a caller to the lower filesystem statfs method.
 - sys_ustat.  Add a non-exported statfs_by_dentry helper for it which
   doesn't won't be able to fill out the flags field later on.

In addition rename the helpers for statfs vs fstatfs to do_*statfs instead
of the misleading vfs prefix.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

Make sure we check the truncate constraints early on in ->setattr by adding
those checks to inode_change_ok.  Also clean up and document inode_change_ok
to make this obvious.

As a fallout we don't have to call inode_newsize_ok from simple_setsize and
simplify it down to a truncate_setsize which doesn't return an error.  This
simplifies a lot of setattr implementations and means we use truncate_setsize
almost everywhere.  Get rid of fat_setsize now that it's trivial and mark
ext2_setsize static to make the calling convention obvious.

Keep the inode_newsize_ok in vmtruncate for now as all callers need an
audit for its removal anyway.

Note: setattr code in ecryptfs doesn't call inode_change_ok at all and
needs a deeper audit, but that is left for later.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

I have encountered the same problem that Eric Sandeen described in
this post

 http://lkml.org/lkml/fancy/2010/4/23/467

while experimenting with stackable filesystems.

The reason seems to be that ecryptfs calls lookup_one_len() to get the
lower dentry, which in turn calls the lower parent dirs d_revalidate()
with a NULL nameidata object.
If ecryptfs is the underlaying filesystem, the NULL pointer dereference
occurs, since ecryptfs is not prepared to handle a NULL nameidata.

I know that this cant happen any more, since it is no longer allowed to
mount ecryptfs upon itself.

But maybe this patch it useful nevertheless, since the problem would still
apply for an underlaying filesystem that implements d_revalidate() and is
not prepared to handle a NULL nameidata (I dont know if there actually
is such a fs).

With this patch (against 2.6.35-rc5) ecryptfs uses the vfs_lookup_path()
function instead of lookup_one_len() which ensures that the nameidata
passed to the lower filesystems d_revalidate().

Signed-off-by: Lino Sanfilippo <LinoSanfilippo@gmx.de>
Signed-off-by: Tyler Hicks <tyhicks@linux.vnet.ibm.com>

The comments in the code indicate that file_info should be released if the
function fails.  This releasing is done at the label out_free, not out.

The semantic match that finds this problem is as follows:
(http://www.emn.fr/x-info/coccinelle/)

// <smpl>
@r exists@
local idexpression x;
statement S;
expression E;
identifier f,f1,l;
position p1,p2;
expression *ptr != NULL;
@@

x@p1 = kmem_cache_zalloc(...);
...
if (x == NULL) S
<... when != x
     when != if (...) { <+...x...+> }
(
x->f1 = E
|
 (x->f1 == NULL || ...)
|
 f(...,x->f1,...)
)
...>
(
 return <+...x...+>;
|
 return@p2 ...;
)

@script:python@
p1 << r.p1;
p2 << r.p2;
@@

print "* file: %s kmem_cache_zalloc %s" % (p1[0].file,p1[0].line)
// </smpl>

Signed-off-by: Julia Lawall <julia@diku.dk>
Cc: stable@kernel.org
Signed-off-by: Tyler Hicks <tyhicks@linux.vnet.ibm.com>