Patch "ext4 crypto: use dget_parent() in ext4_d_revalidate()" has been added to the 4.4-stable tree

This is a note to let you know that I've just added the patch titled

ext4 crypto: use dget_parent() in ext4_d_revalidate()

to the 4.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
ext4-crypto-use-dget_parent-in-ext4_d_revalidate.patch
and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Theodore Ts'o <[email protected]>
Date: Sat, 26 Mar 2016 16:15:42 -0400
Subject: ext4 crypto: use dget_parent() in ext4_d_revalidate()

From: Theodore Ts'o <[email protected]>

commit 3d43bcfef5f0548845a425365011c499875491b0 upstream.

This avoids potential problems caused by a race where the inode gets renamed out from its parent directory and the parent directory is deleted while ext4_d_revalidate() is running.

---
 fs/ext4/crypto.c |   11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

@@ -477,16 +477,21 @@ uint32_t ext4_validate_encryption_key_si
  */
 static int ext4_d_revalidate(struct dentry *dentry, unsigned int flags)
 {
-	struct inode *dir = d_inode(dentry->d_parent);
-	struct ext4_crypt_info *ci = EXT4_I(dir)->i_crypt_info;
+	struct dentry *dir;
+	struct ext4_crypt_info *ci;
 	int dir_has_key, cached_with_key;
 
-	if (!ext4_encrypted_inode(dir))
+	dir = dget_parent(dentry);
+	if (!ext4_encrypted_inode(d_inode(dir))) {
+		dput(dir);
 		return 0;
+	}
+	ci = EXT4_I(d_inode(dir))->i_crypt_info;
 
 	/* this should eventually be an flag in d_flags */
 	cached_with_key = dentry->d_fsdata != NULL;
 	dir_has_key = (ci != NULL);
+	dput(dir);
 
 	/*
 	 * If the dentry was cached without the key, and it is a

Patches currently in stable-queue which might be from [email protected] are

queue-4.4/ext4-fscrypto-avoid-rcu-lookup-in-d_revalidate.patch queue-4.4/ext4-crypto-revalidate-dentry-after-adding-or-removing-the-key.patch queue-4.4/ext4-crypto-use-dget_parent-in-ext4_d_revalidate.patch queue-4.4/ext4-require-encryption-feature-for-ext4_ioc_set_encryption_policy.patch