ecryptfs: switch ecryptfs_decode_and_decrypt_filename() from dentry to sb

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

diff --cc fs/ecryptfs/crypto.c
Simple merge

diff --cc fs/ecryptfs/ecryptfs_kernel.h
Simple merge

diff --cc fs/ecryptfs/file.c
Simple merge

diff --cc fs/ecryptfs/inode.c
Simple merge