proc: Update proc_flush_task_mnt to use d_invalidate

Now that d_invalidate always succeeds and flushes mount points use
it in stead of a combination of shrink_dcache_parent and d_drop
in proc_flush_task_mnt.  This removes the danger of a mount point
under /proc/<pid>/... becoming unreachable after the d_drop.

Reviewed-by: Miklos Szeredi <miklos@szeredi.hu>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 2 insertions, 4 deletions

diff --git a/fs/proc/base.c b/fs/proc/base.c
index b4fe0ee08942..00cd85f18bcc 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -2639,8 +2639,7 @@ static void proc_flush_task_mnt(struct vfsmount *mnt, pid_t pid, pid_t tgid)
         /* no ->d_hash() rejects on procfs */
         dentry = d_hash_and_lookup(mnt->mnt_root, &name);
         if (dentry) {
-                shrink_dcache_parent(dentry);
-                d_drop(dentry);
+                d_invalidate(dentry);
                 dput(dentry);
         }
 
@@ -2660,8 +2659,7 @@ static void proc_flush_task_mnt(struct vfsmount *mnt, pid_t pid, pid_t tgid)
         name.len = snprintf(buf, sizeof(buf), "%d", pid);
         dentry = d_hash_and_lookup(dir, &name);
         if (dentry) {
-                shrink_dcache_parent(dentry);
-                d_drop(dentry);
+                d_invalidate(dentry);
                 dput(dentry);
         }