4 files changed, 12 insertions, 1 deletions

diff --git a/fs/namei.c b/fs/namei.c
index 9d3033dc22e9..dc50bfb2f5d6 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -908,6 +908,12 @@ static int follow_automount(struct path *path, unsigned flags,
         if (!path->dentry->d_op || !path->dentry->d_op->d_automount)
                 return -EREMOTE;
 
+        /* We don't want to mount if someone supplied AT_NO_AUTOMOUNT
+         * and this is the terminal part of the path.
+         */
+        if ((flags & LOOKUP_NO_AUTOMOUNT) && !(flags & LOOKUP_CONTINUE))
+                return -EISDIR; /* we actually want to stop here */
+
         /* We want to mount if someone is trying to open/create a file of any
          * type under the mountpoint, wants to traverse through the mountpoint
          * or wants to open the mounted directory.
diff --git a/fs/stat.c b/fs/stat.c
index 12e90e213900..d5c61cf2b703 100644
--- a/fs/stat.c
+++ b/fs/stat.c
@@ -75,11 +75,13 @@ int vfs_fstatat(int dfd, const char __user *filename, struct kstat *stat,
         int error = -EINVAL;
         int lookup_flags = 0;
 
-        if ((flag & ~AT_SYMLINK_NOFOLLOW) != 0)
+        if ((flag & ~(AT_SYMLINK_NOFOLLOW | AT_NO_AUTOMOUNT)) != 0)
                 goto out;
 
         if (!(flag & AT_SYMLINK_NOFOLLOW))
                 lookup_flags |= LOOKUP_FOLLOW;
+        if (flag & AT_NO_AUTOMOUNT)
+                lookup_flags |= LOOKUP_NO_AUTOMOUNT;
 
         error = user_path_at(dfd, filename, lookup_flags, &path);
         if (error)
diff --git a/include/linux/fcntl.h b/include/linux/fcntl.h
index afc00af3229b..a562fa5fb4e3 100644
--- a/include/linux/fcntl.h
+++ b/include/linux/fcntl.h
@@ -45,6 +45,7 @@
 #define AT_REMOVEDIR            0x200   /* Remove directory instead of
                                            unlinking file.  */
 #define AT_SYMLINK_FOLLOW       0x400   /* Follow symbolic links.  */
+#define AT_NO_AUTOMOUNT         0x800   /* Suppress terminal automount traversal */
 
 #ifdef __KERNEL__
 
diff --git a/include/linux/namei.h b/include/linux/namei.h
index 8ef2c789c2a8..f276d4fa01fc 100644
--- a/include/linux/namei.h
+++ b/include/linux/namei.h
@@ -45,6 +45,7 @@ enum {LAST_NORM, LAST_ROOT, LAST_DOT, LAST_DOTDOT, LAST_BIND};
  *  - ending slashes ok even for nonexistent files
  *  - internal "there are more path components" flag
  *  - dentry cache is untrusted; force a real lookup
+ *  - suppress terminal automount
  */
 #define LOOKUP_FOLLOW           0x0001
 #define LOOKUP_DIRECTORY        0x0002
@@ -53,6 +54,7 @@ enum {LAST_NORM, LAST_ROOT, LAST_DOT, LAST_DOTDOT, LAST_BIND};
 #define LOOKUP_PARENT           0x0010
 #define LOOKUP_REVAL            0x0020
 #define LOOKUP_RCU              0x0040
+#define LOOKUP_NO_AUTOMOUNT     0x0080
 /*
  * Intent data
  */