kill d_instantiate_no_diralias()

The only user is fuse_create_new_entry(), and there it's used to
mitigate the same mkdir/open-by-handle race as in nfs_mkdir().
The same solution applies - unhash the mkdir argument, then
call d_splice_alias() and if that returns a reference to preexisting
alias, dput() and report success.  ->mkdir() argument left unhashed
negative with the preexisting alias moved in the right place is just
fine from the ->mkdir() callers point of view.

Cc: Miklos Szeredi <miklos@szeredi.hu>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 11 insertions, 4 deletions

diff --git a/fs/fuse/dir.c b/fs/fuse/dir.c
index 56231b31f806..4bbae6ac75c3 100644
--- a/fs/fuse/dir.c
+++ b/fs/fuse/dir.c
@@ -539,6 +539,7 @@ static int create_new_entry(struct fuse_conn *fc, struct fuse_args *args,
 {
         struct fuse_entry_out outarg;
         struct inode *inode;
+        struct dentry *d;
         int err;
         struct fuse_forget_link *forget;
 
@@ -570,11 +571,17 @@ static int create_new_entry(struct fuse_conn *fc, struct fuse_args *args,
         }
         kfree(forget);
 
-        err = d_instantiate_no_diralias(entry, inode);
-        if (err)
-                return err;
+        d_drop(entry);
+        d = d_splice_alias(inode, entry);
+        if (IS_ERR(d))
+                return PTR_ERR(d);
 
-        fuse_change_entry_timeout(entry, &outarg);
+        if (d) {
+                fuse_change_entry_timeout(d, &outarg);
+                dput(d);
+        } else {
+                fuse_change_entry_timeout(entry, &outarg);
+        }
         fuse_invalidate_attr(dir);
         return 0;