ext4/fscrypto: avoid RCU lookup in d_revalidate

As Al pointed, d_revalidate should return RCU lookup before using d_inode.
This was originally introduced by:
commit 34286d666230 ("fs: rcu-walk aware d_revalidate method").

Reported-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
Cc: Theodore Ts'o <tytso@mit.edu>
Cc: stable <stable@vger.kernel.org>

2 files changed, 8 insertions, 0 deletions

diff --git a/fs/crypto/crypto.c b/fs/crypto/crypto.c
index da70520f3ab4..2fc8c43ce531 100644
--- a/fs/crypto/crypto.c
+++ b/fs/crypto/crypto.c
@@ -26,6 +26,7 @@
 #include <linux/ratelimit.h>
 #include <linux/bio.h>
 #include <linux/dcache.h>
+#include <linux/namei.h>
 #include <linux/fscrypto.h>
 #include <linux/ecryptfs.h>
 
@@ -353,6 +354,9 @@ static int fscrypt_d_revalidate(struct dentry *dentry, unsigned int flags)
         struct fscrypt_info *ci;
         int dir_has_key, cached_with_key;
 
+        if (flags & LOOKUP_RCU)
+                return -ECHILD;
+
         dir = dget_parent(dentry);
         if (!d_inode(dir)->i_sb->s_cop->is_encrypted(d_inode(dir))) {
                 dput(dir);
diff --git a/fs/ext4/crypto.c b/fs/ext4/crypto.c
index db9ae6e18154..6a6c27373b54 100644
--- a/fs/ext4/crypto.c
+++ b/fs/ext4/crypto.c
@@ -32,6 +32,7 @@
 #include <linux/random.h>
 #include <linux/scatterlist.h>
 #include <linux/spinlock_types.h>
+#include <linux/namei.h>
 
 #include "ext4_extents.h"
 #include "xattr.h"
@@ -482,6 +483,9 @@ static int ext4_d_revalidate(struct dentry *dentry, unsigned int flags)
         struct ext4_crypt_info *ci;
         int dir_has_key, cached_with_key;
 
+        if (flags & LOOKUP_RCU)
+                return -ECHILD;
+
         dir = dget_parent(dentry);
         if (!ext4_encrypted_inode(d_inode(dir))) {
                 dput(dir);