1 files changed, 50 insertions, 1 deletions

diff --git a/fs/proc/root.c b/fs/proc/root.c
index f4b1a9d2eca6..fe4f64b3250b 100644
--- a/fs/proc/root.c
+++ b/fs/proc/root.c
@@ -23,6 +23,7 @@
 #include <linux/pid_namespace.h>
 #include <linux/parser.h>
 #include <linux/cred.h>
+#include <linux/magic.h>
 
 #include "internal.h"
 
@@ -36,7 +37,7 @@ static const match_table_t tokens = {
         {Opt_err, NULL},
 };
 
-int proc_parse_options(char *options, struct pid_namespace *pid)
+static int proc_parse_options(char *options, struct pid_namespace *pid)
 {
         char *p;
         substring_t args[MAX_OPT_ARGS];
@@ -78,6 +79,54 @@ int proc_parse_options(char *options, struct pid_namespace *pid)
         return 1;
 }
 
+static int proc_fill_super(struct super_block *s, void *data, int silent)
+{
+        struct pid_namespace *ns = get_pid_ns(s->s_fs_info);
+        struct inode *root_inode;
+        int ret;
+
+        if (!proc_parse_options(data, ns))
+                return -EINVAL;
+
+        /* User space would break if executables or devices appear on proc */
+        s->s_iflags |= SB_I_USERNS_VISIBLE | SB_I_NOEXEC | SB_I_NODEV;
+        s->s_flags |= SB_NODIRATIME | SB_NOSUID | SB_NOEXEC;
+        s->s_blocksize = 1024;
+        s->s_blocksize_bits = 10;
+        s->s_magic = PROC_SUPER_MAGIC;
+        s->s_op = &proc_sops;
+        s->s_time_gran = 1;
+
+        /*
+         * procfs isn't actually a stacking filesystem; however, there is
+         * too much magic going on inside it to permit stacking things on
+         * top of it
+         */
+        s->s_stack_depth = FILESYSTEM_MAX_STACK_DEPTH;
+        
+        /* procfs dentries and inodes don't require IO to create */
+        s->s_shrink.seeks = 0;
+
+        pde_get(&proc_root);
+        root_inode = proc_get_inode(s, &proc_root);
+        if (!root_inode) {
+                pr_err("proc_fill_super: get root inode failed\n");
+                return -ENOMEM;
+        }
+
+        s->s_root = d_make_root(root_inode);
+        if (!s->s_root) {
+                pr_err("proc_fill_super: allocate dentry failed\n");
+                return -ENOMEM;
+        }
+
+        ret = proc_setup_self(s);
+        if (ret) {
+                return ret;
+        }
+        return proc_setup_thread_self(s);
+}
+
 int proc_remount(struct super_block *sb, int *flags, char *data)
 {
         struct pid_namespace *pid = sb->s_fs_info;