Btrfs: fix oops when btrfs_inherit_iflags called with a NULL dir

This happens during subvol creation.

Signed-off-by: Chris Mason <chris.mason@oracle.com>

diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index 926332a..eff18f5 100644 (file)
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -112,7 +112,12 @@ void btrfs_update_iflags(struct inode *inode)
  */
 void btrfs_inherit_iflags(struct inode *inode, struct inode *dir)
 {
-       unsigned int flags = BTRFS_I(dir)->flags;
+       unsigned int flags;
+
+       if (!dir)
+               return;
+
+       flags = BTRFS_I(dir)->flags;
 
        if (S_ISREG(inode->i_mode))
                flags &= ~BTRFS_INODE_DIRSYNC;