ecryptfs: clean up (un)lock_parent

dget(dentry->d_parent) --> dget_parent(dentry)

unlock_parent() is racy and unnecessary.  Replace single caller with
unlock_dir().

There are several other suspect uses of ->d_parent in ecryptfs...

Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Cc: Michael Halcrow <mhalcrow@us.ibm.com>
Cc: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 4 insertions, 9 deletions

diff --git a/fs/ecryptfs/inode.c b/fs/ecryptfs/inode.c
index 0a1397335a8e..c92cc1c00aae 100644
--- a/fs/ecryptfs/inode.c
+++ b/fs/ecryptfs/inode.c
@@ -37,17 +37,11 @@ static struct dentry *lock_parent(struct dentry *dentry)
 {
         struct dentry *dir;
 
-        dir = dget(dentry->d_parent);
+        dir = dget_parent(dentry);
         mutex_lock_nested(&(dir->d_inode->i_mutex), I_MUTEX_PARENT);
         return dir;
 }
 
-static void unlock_parent(struct dentry *dentry)
-{
-        mutex_unlock(&(dentry->d_parent->d_inode->i_mutex));
-        dput(dentry->d_parent);
-}
-
 static void unlock_dir(struct dentry *dir)
 {
         mutex_unlock(&dir->d_inode->i_mutex);
@@ -426,8 +420,9 @@ static int ecryptfs_unlink(struct inode *dir, struct dentry *dentry)
         int rc = 0;
         struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
         struct inode *lower_dir_inode = ecryptfs_inode_to_lower(dir);
+        struct dentry *lower_dir_dentry;
 
-        lock_parent(lower_dentry);
+        lower_dir_dentry = lock_parent(lower_dentry);
         rc = vfs_unlink(lower_dir_inode, lower_dentry);
         if (rc) {
                 printk(KERN_ERR "Error in vfs_unlink; rc = [%d]\n", rc);
@@ -439,7 +434,7 @@ static int ecryptfs_unlink(struct inode *dir, struct dentry *dentry)
         dentry->d_inode->i_ctime = dir->i_ctime;
         d_drop(dentry);
 out_unlock:
-        unlock_parent(lower_dentry);
+        unlock_dir(lower_dir_dentry);
         return rc;
 }