convert pstore

object creation by d_alloc_name()+d_add() in pstore_mkfile(), removal -
via normal VFS codepaths (with ->unlink() using simple_unlink()) or
in pstore_put_backend_records() via locked_recursive_removal()

Replace d_add() with d_make_persistent()+dput() - that's what really
happens there.  The reference that goes into record->dentry is valid
only until the unlink (and explicitly cleared by pstore_unlink()).

Reviewed-by: Kees Cook <kees@kernel.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

diff --git a/fs/pstore/inode.c b/fs/pstore/inode.c
index b4e55c90f8dc236362da829613709c40938497d5..71deffcc33567e23b014f2ec44591b6200864d9b 100644 (file)
--- a/fs/pstore/inode.c
+++ b/fs/pstore/inode.c
@@ -373,7 +373,7 @@ int pstore_mkfile(struct dentry *root, struct pstore_record *record)
        if (!dentry)
                return -ENOMEM;
 
-       private->dentry = dentry;
+       private->dentry = dentry; // borrowed
        private->record = record;
        inode->i_size = private->total_size = size;
        inode->i_private = private;
@@ -382,7 +382,8 @@ int pstore_mkfile(struct dentry *root, struct pstore_record *record)
                inode_set_mtime_to_ts(inode,
                                      inode_set_ctime_to_ts(inode, record->time));
 
-       d_add(dentry, no_free_ptr(inode));
+       d_make_persistent(dentry, no_free_ptr(inode));
+       dput(dentry);
 
        list_add(&(no_free_ptr(private))->list, &records_list);
 
@@ -465,7 +466,7 @@ static void pstore_kill_sb(struct super_block *sb)
        guard(mutex)(&pstore_sb_lock);
        WARN_ON(pstore_sb && pstore_sb != sb);
 
-       kill_litter_super(sb);
+       kill_anon_super(sb);
        pstore_sb = NULL;
 
        guard(mutex)(&records_list_lock);