[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, 8 insertions, 6 deletions

diff --git a/fs/namespace.c b/fs/namespace.c
index cefa1d9939b0..dfdf51e81c1c 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -724,20 +724,21 @@ void save_mount_options(struct super_block *sb, char *options)
 }
 EXPORT_SYMBOL(save_mount_options);
 
+#ifdef CONFIG_PROC_FS
 /* iterator */
 static void *m_start(struct seq_file *m, loff_t *pos)
 {
-        struct mnt_namespace *n = m->private;
+        struct proc_mounts *p = m->private;
 
         down_read(&namespace_sem);
-        return seq_list_start(&n->list, *pos);
+        return seq_list_start(&p->ns->list, *pos);
 }
 
 static void *m_next(struct seq_file *m, void *v, loff_t *pos)
 {
-        struct mnt_namespace *n = m->private;
+        struct proc_mounts *p = m->private;
 
-        return seq_list_next(v, &n->list, pos);
+        return seq_list_next(v, &p->ns->list, pos);
 }
 
 static void m_stop(struct seq_file *m, void *v)
@@ -794,7 +795,7 @@ static int show_vfsmnt(struct seq_file *m, void *v)
         return err;
 }
 
-struct seq_operations mounts_op = {
+const struct seq_operations mounts_op = {
         .start  = m_start,
         .next   = m_next,
         .stop   = m_stop,
@@ -833,12 +834,13 @@ static int show_vfsstat(struct seq_file *m, void *v)
         return err;
 }
 
-struct seq_operations mountstats_op = {
+const struct seq_operations mountstats_op = {
         .start  = m_start,
         .next   = m_next,
         .stop   = m_stop,
         .show   = show_vfsstat,
 };
+#endif  /* CONFIG_PROC_FS */
 
 /**
  * may_umount_tree - check if a mount tree is busy