procfs: switch /proc/self away from proc_dir_entry

Just have it pinned in dcache all along and let procfs ->kill_sb()
drop it before kill_anon_super().

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 12 insertions, 4 deletions

diff --git a/fs/proc/base.c b/fs/proc/base.c
index 69078c7cef1f..593e7c5ddb49 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -2794,7 +2794,7 @@ retry:
         return iter;
 }
 
-#define TGID_OFFSET (FIRST_PROCESS_ENTRY)
+#define TGID_OFFSET (FIRST_PROCESS_ENTRY + 1)
 
 static int proc_pid_fill_cache(struct file *filp, void *dirent, filldir_t filldir,
         struct tgid_iter iter)
@@ -2817,13 +2817,21 @@ int proc_pid_readdir(struct file * filp, void * dirent, filldir_t filldir)
         struct tgid_iter iter;
         struct pid_namespace *ns;
         filldir_t __filldir;
+        loff_t pos = filp->f_pos;
 
-        if (filp->f_pos >= PID_MAX_LIMIT + TGID_OFFSET)
+        if (pos >= PID_MAX_LIMIT + TGID_OFFSET)
                 goto out;
 
-        ns = filp->f_dentry->d_sb->s_fs_info;
+        if (pos == TGID_OFFSET - 1) {
+                if (proc_fill_cache(filp, dirent, filldir, "self", 4,
+                                        NULL, NULL, NULL) < 0)
+                        goto out;
+                iter.tgid = 0;
+        } else {
+                iter.tgid = pos - TGID_OFFSET;
+        }
         iter.task = NULL;
-        iter.tgid = filp->f_pos - TGID_OFFSET;
+        ns = filp->f_dentry->d_sb->s_fs_info;
         for (iter = next_tgid(ns, iter);
              iter.task;
              iter.tgid += 1, iter = next_tgid(ns, iter)) {