From: Theodore Ts'o <tytso@xxxxxxx> commit 3d43bcfef5f0548845a425365011c499875491b0 upstream. Please apply to 4.4-stable. 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. Fixes: 28b4c263961c Reported-by: Al Viro <viro@xxxxxxxxxxxxxxxxxx> Signed-off-by: Theodore Ts'o <tytso@xxxxxxx> Cc: stable@xxxxxxxxxxxxxxx Signed-off-by: Eric Biggers <ebiggers@xxxxxxxxxx> --- fs/ext4/crypto.c | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-) diff --git a/fs/ext4/crypto.c b/fs/ext4/crypto.c index 13a69e0fb90d..1259ade2f10a 100644 --- a/fs/ext4/crypto.c +++ b/fs/ext4/crypto.c @@ -477,16 +477,21 @@ uint32_t ext4_validate_encryption_key_size(uint32_t mode, uint32_t size) */ 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 -- 2.13.0.rc1.294.g07d810a77f-goog