eCryptfs: do not try to open device files on mknod

When creating device nodes, eCryptfs needs to delay actually opening the lower
persistent file until an application tries to open.  Device handles may not be
backed by anything when they first come into existence.

[Valdis.Kletnieks@vt.edu: build fix]
Signed-off-by: Michael Halcrow <mhalcrow@us.ibm.com>
Cc: <Valdis.Kletnieks@vt.edu}
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 14 insertions, 0 deletions

diff --git a/fs/ecryptfs/file.c b/fs/ecryptfs/file.c
index f0be29051528..2c2d60df3f60 100644
--- a/fs/ecryptfs/file.c
+++ b/fs/ecryptfs/file.c
@@ -199,6 +199,20 @@ static int ecryptfs_open(struct inode *inode, struct file *file)
                        "file must hence be opened RO\n", __func__);
                 goto out;
         }
+        if (!ecryptfs_inode_to_private(inode)->lower_file) {
+                BUG_ON(!(crypt_stat->flags & ECRYPTFS_DELAY_PERSISTENT));
+                mutex_lock(&crypt_stat->cs_mutex);
+                crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
+                mutex_unlock(&crypt_stat->cs_mutex);
+                rc = ecryptfs_init_persistent_file(ecryptfs_dentry);
+                if (rc) {
+                        printk(KERN_ERR "%s: Error attempting to initialize "
+                               "the persistent file for the dentry with name "
+                               "[%s]; rc = [%d]\n", __func__,
+                               ecryptfs_dentry->d_name.name, rc);
+                        goto out;
+                }
+        }
         ecryptfs_set_file_lower(
                 file, ecryptfs_inode_to_private(inode)->lower_file);
         if (S_ISDIR(ecryptfs_dentry->d_inode->i_mode)) {