[PATCH 1/1] fix d_revalidate oopsen on NFS exports

[Chris Dunlop]

can't blindly check nd->flags in ->d_revalidate()

Has been previously done for various other file systems:

git blame -L 1768,+1 fs/proc/base.c
34286d66 (Nick Piggin 2011-01-07 17:49:57 +1100 1768) 	if (nd && nd->flags & LOOKUP_RCU)
git blame -L 645,+1 fs/cifs/dir.c
3ca30d40 (Pavel Shilovsky 2011-07-25 17:59:10 +0400 645) 	if (nd && (nd->flags & LOOKUP_RCU))
git blame -L 46,+1 fs/fat/namei_vfat.c
9177ada9 (Al Viro 2011-03-10 03:45:49 -0500 46) 	if (nd && nd->flags & LOOKUP_RCU)
git blame -L 57,+1 fs/fat/namei_vfat.c
9177ada9 (Al Viro 2011-03-10 03:45:49 -0500 57) 	if (nd && nd->flags & LOOKUP_RCU)
git blame -L 177,+1 fs/fuse/dir.c
d2433905 (Miklos Szeredi 2011-05-10 17:35:58 +0200 177) 		if (nd && (nd->flags & LOOKUP_RCU))
git blame -L 1036,+1 fs/ceph/dir.c
0eb980e3 (Al Viro 2011-03-10 03:44:05 -0500 1036) 	if (nd && nd->flags & LOOKUP_RCU)
git blame -L 47,+1 fs/gfs2/dentry.c
53fe9241 (Al Viro 2011-03-10 03:44:48 -0500 47) 	if (nd && nd->flags & LOOKUP_RCU)
git blame -L 53,+1 fs/ecryptfs/dentry.c
70b89021 (Tyler Hicks 2011-02-17 17:35:20 -0600 53) 	if (nd && nd->flags & LOOKUP_RCU)
git blame -L 59,+1 fs/ocfs2/dcache.c
4714e637 (Al Viro 2011-03-10 03:45:07 -0500 59) 	if (nd && nd->flags & LOOKUP_RCU)

Signed-off-by: Chris Dunlop <chris at onthe.net.au>
---
 fs/9p/vfs_dentry.c    |    2 +-
 fs/afs/dir.c          |    2 +-
 fs/coda/dir.c         |    2 +-
 fs/hfs/sysdep.c       |    2 +-
 fs/jfs/namei.c        |    3 +++
 fs/ncpfs/dir.c        |    2 +-
 fs/nfs/dir.c          |    2 +-
 fs/proc/proc_sysctl.c |    2 +-
 fs/sysfs/dir.c        |    2 +-
 9 files changed, 11 insertions(+), 8 deletions(-)

diff --git a/fs/9p/vfs_dentry.c b/fs/9p/vfs_dentry.c
index e022890..2be4b91 100644
--- a/fs/9p/vfs_dentry.c
+++ b/fs/9p/vfs_dentry.c
@@ -106,7 +106,7 @@ static int v9fs_lookup_revalidate(struct dentry *dentry, struct nameidata *nd)
 	struct inode *inode;
 	struct v9fs_inode *v9inode;
 
-	if (nd->flags & LOOKUP_RCU)
+	if (nd && nd->flags & LOOKUP_RCU)
 		return -ECHILD;
 
 	inode = dentry->d_inode;
diff --git a/fs/afs/dir.c b/fs/afs/dir.c
index 1b0b195..4112d68 100644
--- a/fs/afs/dir.c
+++ b/fs/afs/dir.c
@@ -607,7 +607,7 @@ static int afs_d_revalidate(struct dentry *dentry, struct nameidata *nd)
 	void *dir_version;
 	int ret;
 
-	if (nd->flags & LOOKUP_RCU)
+	if (nd && nd->flags & LOOKUP_RCU)
 		return -ECHILD;
 
 	vnode = AFS_FS_I(dentry->d_inode);
diff --git a/fs/coda/dir.c b/fs/coda/dir.c
index 28e7e13..0cf4a68 100644
--- a/fs/coda/dir.c
+++ b/fs/coda/dir.c
@@ -544,7 +544,7 @@ static int coda_dentry_revalidate(struct dentry *de, struct nameidata *nd)
 	struct inode *inode;
 	struct coda_inode_info *cii;
 
-	if (nd->flags & LOOKUP_RCU)
+	if (nd && nd->flags & LOOKUP_RCU)
 		return -ECHILD;
 
 	inode = de->d_inode;
diff --git a/fs/hfs/sysdep.c b/fs/hfs/sysdep.c
index 19cf291..1127ea3 100644
--- a/fs/hfs/sysdep.c
+++ b/fs/hfs/sysdep.c
@@ -18,7 +18,7 @@ static int hfs_revalidate_dentry(struct dentry *dentry, struct nameidata *nd)
 	struct inode *inode;
 	int diff;
 
-	if (nd->flags & LOOKUP_RCU)
+	if (nd && nd->flags & LOOKUP_RCU)
 		return -ECHILD;
 
 	inode = dentry->d_inode;
diff --git a/fs/jfs/namei.c b/fs/jfs/namei.c
index a112ad9..e3b65d6 100644
--- a/fs/jfs/namei.c
+++ b/fs/jfs/namei.c
@@ -1585,6 +1585,9 @@ out:
 
 static int jfs_ci_revalidate(struct dentry *dentry, struct nameidata *nd)
 {
+	if (nd && (nd->flags & LOOKUP_RCU))
+		return -ECHILD;
+
 	/*
 	 * This is not negative dentry. Always valid.
 	 *
diff --git a/fs/ncpfs/dir.c b/fs/ncpfs/dir.c
index 9c51f62..1fb3de3 100644
--- a/fs/ncpfs/dir.c
+++ b/fs/ncpfs/dir.c
@@ -302,7 +302,7 @@ ncp_lookup_validate(struct dentry *dentry, struct nameidata *nd)
 	if (dentry == dentry->d_sb->s_root)
 		return 1;
 
-	if (nd->flags & LOOKUP_RCU)
+	if (nd && nd->flags & LOOKUP_RCU)
 		return -ECHILD;
 
 	parent = dget_parent(dentry);
diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c
index b238d95..88c0f6e 100644
--- a/fs/nfs/dir.c
+++ b/fs/nfs/dir.c
@@ -1103,7 +1103,7 @@ static int nfs_lookup_revalidate(struct dentry *dentry, struct nameidata *nd)
 	struct nfs_fattr *fattr = NULL;
 	int error;
 
-	if (nd->flags & LOOKUP_RCU)
+	if (nd && nd->flags & LOOKUP_RCU)
 		return -ECHILD;
 
 	parent = dget_parent(dentry);
diff --git a/fs/proc/proc_sysctl.c b/fs/proc/proc_sysctl.c
index a6b6217..0437e4a 100644
--- a/fs/proc/proc_sysctl.c
+++ b/fs/proc/proc_sysctl.c
@@ -435,7 +435,7 @@ static const struct inode_operations proc_sys_dir_operations = {
 
 static int proc_sys_revalidate(struct dentry *dentry, struct nameidata *nd)
 {
-	if (nd->flags & LOOKUP_RCU)
+	if (nd && nd->flags & LOOKUP_RCU)
 		return -ECHILD;
 	return !PROC_I(dentry->d_inode)->sysctl->unregistering;
 }
diff --git a/fs/sysfs/dir.c b/fs/sysfs/dir.c
index 7fdf6a7..8f36a13 100644
--- a/fs/sysfs/dir.c
+++ b/fs/sysfs/dir.c
@@ -261,7 +261,7 @@ static int sysfs_dentry_revalidate(struct dentry *dentry, struct nameidata *nd)
 	struct sysfs_dirent *sd;
 	int is_dir;
 
-	if (nd->flags & LOOKUP_RCU)
+	if (nd && nd->flags & LOOKUP_RCU)
 		return -ECHILD;
 
 	sd = dentry->d_fsdata;
-- 
1.7.0.4