[patch 5/7] vfs: mountinfo: allow using process root

Allow /proc/<pid>/mountinfo to use the root of <pid> to calculate
mountpoints.

 - move definition of 'struct proc_mounts' to <linux/mnt_namespace.h>
 - add the process's namespace and root to this structure
 - pass a pointer to 'struct proc_mounts' into seq_operations

In addition the following cleanups are made:

 - use a common open function for /proc/<pid>/{mounts,mountstat}
 - surround namespace.c part of these proc files with #ifdef CONFIG_PROC_FS
 - make the seq_operations structures const

Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 11 insertions, 0 deletions

diff --git a/include/linux/mnt_namespace.h b/include/linux/mnt_namespace.h
index 8eed44f8ca73..c078aacc8116 100644
--- a/include/linux/mnt_namespace.h
+++ b/include/linux/mnt_namespace.h
@@ -5,6 +5,7 @@
 #include <linux/mount.h>
 #include <linux/sched.h>
 #include <linux/nsproxy.h>
+#include <linux/seq_file.h>
 
 struct mnt_namespace {
         atomic_t                count;
@@ -14,6 +15,13 @@ struct mnt_namespace {
         int event;
 };
 
+struct proc_mounts {
+        struct seq_file m; /* must be the first element */
+        struct mnt_namespace *ns;
+        struct path root;
+        int event;
+};
+
 extern struct mnt_namespace *copy_mnt_ns(unsigned long, struct mnt_namespace *,
                 struct fs_struct *);
 extern void __put_mnt_ns(struct mnt_namespace *ns);
@@ -37,5 +45,8 @@ static inline void get_mnt_ns(struct mnt_namespace *ns)
         atomic_inc(&ns->count);
 }
 
+extern const struct seq_operations mounts_op;
+extern const struct seq_operations mountstats_op;
+
 #endif
 #endif