Make ->d_sb assign-once and always non-NULL

New helper (non-exported, fs/internal.h-only): __d_alloc(sb, name).
Allocates dentry, sets its ->d_sb to given superblock and sets
->d_op accordingly.  Old d_alloc(NULL, name) callers are converted
to that (all of them know what superblock they want).  d_alloc()
itself is left only for parent != NULl case; uses __d_alloc(),
inserts result into the list of parent's children.

Note that now ->d_sb is assign-once and never NULL *and*
->d_parent is never NULL either.

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

1 files changed, 3 insertions, 3 deletions

diff --git a/fs/libfs.c b/fs/libfs.c
index 275ca4749a2e..bd50b11f92da 100644
--- a/fs/libfs.c
+++ b/fs/libfs.c
@@ -16,6 +16,8 @@
 
 #include <asm/uaccess.h>
 
+#include "internal.h"
+
 static inline int simple_positive(struct dentry *dentry)
 {
         return dentry->d_inode && !d_unhashed(dentry);
@@ -246,13 +248,11 @@ struct dentry *mount_pseudo(struct file_system_type *fs_type, char *name,
         root->i_ino = 1;
         root->i_mode = S_IFDIR | S_IRUSR | S_IWUSR;
         root->i_atime = root->i_mtime = root->i_ctime = CURRENT_TIME;
-        dentry = d_alloc(NULL, &d_name);
+        dentry = __d_alloc(s, &d_name);
         if (!dentry) {
                 iput(root);
                 goto Enomem;
         }
-        dentry->d_sb = s;
-        dentry->d_parent = dentry;
         d_instantiate(dentry, root);
         s->s_root = dentry;
         s->s_d_op = dops;