From a6f15d9a756571babbb2b2cd4fdd1b64a5de232b Mon Sep 17 00:00:00 2001 From: Miklos Szeredi Date: Mon, 22 Jun 2015 13:53:48 +0200 Subject: ovl: don't traverse automount points NFS and other distributed filesystems may place automount points in the tree. Previoulsy overlayfs refused to mount such filesystems types (based on the existence of the .d_automount callback), even if the actual export didn't have any automount points. It cannot be determined in advance whether the filesystem has automount points or not. The solution is to allow fs with .d_automount but refuse to traverse any automount points encountered. Signed-off-by: Miklos Szeredi --- fs/overlayfs/super.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c index bf8537c7f455..de9d2ee68ccf 100644 --- a/fs/overlayfs/super.c +++ b/fs/overlayfs/super.c @@ -303,6 +303,10 @@ static inline struct dentry *ovl_lookup_real(struct dentry *dir, } else if (!dentry->d_inode) { dput(dentry); dentry = NULL; + } else if (dentry->d_flags & DCACHE_MANAGED_DENTRY) { + dput(dentry); + /* Don't support traversing automounts */ + dentry = ERR_PTR(-EREMOTE); } return dentry; } @@ -700,12 +704,12 @@ static bool ovl_is_allowed_fs_type(struct dentry *root) /* * We don't support: - * - automount filesystems + * - autofs * - filesystems with revalidate (FIXME for lower layer) * - filesystems with case insensitive names */ if (dop && - (dop->d_manage || dop->d_automount || + (dop->d_manage || dop->d_revalidate || dop->d_weak_revalidate || dop->d_compare || dop->d_hash)) { return false; -- cgit v1.2.1