Merge branch 'fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

Pull vfs fixes from Al Viro:
 "A couple of fixes for old crap in ->atomic_open() instances"

* 'fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  cifs_atomic_open(): fix double-put on late allocation failure
  gfs2_atomic_open(): fix O_EXCL|O_CREAT handling on cold dcache

Documentation/filesystems/porting.rst

@@ -850,3 +850,11 @@ business doing so.
 d_alloc_pseudo() is internal-only; uses outside of alloc_file_pseudo() are
 very suspect (and won't work in modules).  Such uses are very likely to
 be misspelled d_alloc_anon().
+
+---
+
+**mandatory**
+
+[should've been added in 2016] stale comment in finish_open() nonwithstanding,
+failure exits in ->atomic_open() instances should *NOT* fput() the file,
+no matter what.  Everything is handled by the caller.

fs/cifs/dir.c

@@ -555,7 +555,6 @@ cifs_atomic_open(struct inode *inode, struct dentry *direntry,
 		if (server->ops->close)
 			server->ops->close(xid, tcon, &fid);
 		cifs_del_pending_open(&open);
-		fput(file);
 		rc = -ENOMEM;
 	}
 

fs/gfs2/inode.c

@@ -1248,7 +1248,7 @@ static int gfs2_atomic_open(struct inode *dir, struct dentry *dentry,
 		if (!(file->f_mode & FMODE_OPENED))
 			return finish_no_open(file, d);
 		dput(d);
-		return 0;
+		return excl && (flags & O_CREAT) ? -EEXIST : 0;
 	}
 
 	BUG_ON(d != NULL);

fs/open.c

@@ -860,9 +860,6 @@ cleanup_file:
  * the return value of d_splice_alias(), then the caller needs to perform dput()
  * on it after finish_open().
  *
- * On successful return @file is a fully instantiated open file.  After this, if
- * an error occurs in ->atomic_open(), it needs to clean up with fput().
- *
  * Returns zero on success or -errno if the open failed.
  */
 int finish_open(struct file *file, struct dentry *dentry,