[bug report] fs/ntfs3: Add file operations and implementation

[Dan Carpenter <dan.carpenter@oracle.com>]

Hello Konstantin Komarov,

This is a semi-automatic email about new static checker warnings.

The patch 4342306f0f0d: "fs/ntfs3: Add file operations and
implementation" from Aug 13, 2021, leads to the following Smatch
complaint:

    fs/ntfs3/namei.c:446 ntfs_rename()
    warn: variable dereferenced before check 'old_inode' (see line 312)

fs/ntfs3/namei.c
   311	
   312		if (ntfs_is_meta_file(sbi, old_inode->i_ino)) {
                                           ^^^^^^^^^^^^^^^^
Dereference

   313			err = -EINVAL;
   314			goto out;
   315		}
   316	
   317		if (new_inode) {
   318			/*target name exists. unlink it*/
   319			dget(new_dentry);
   320			ni_lock_dir(new_dir_ni);
   321			err = ntfs_unlink_inode(new_dir, new_dentry);
   322			ni_unlock(new_dir_ni);
   323			dput(new_dentry);
   324			if (err)
   325				goto out;
   326		}
   327	
   328		/* allocate PATH_MAX bytes */
   329		old_de = __getname();
   330		if (!old_de) {
   331			err = -ENOMEM;
   332			goto out;
   333		}
   334	
   335		err = fill_name_de(sbi, old_de, &old_dentry->d_name, NULL);
   336		if (err < 0)
   337			goto out1;
   338	
   339		old_name = (struct ATTR_FILE_NAME *)(old_de + 1);
   340	
   341		if (is_same) {
   342			new_de = old_de;
   343		} else {
   344			new_de = Add2Ptr(old_de, 1024);
   345			err = fill_name_de(sbi, new_de, &new_dentry->d_name, NULL);
   346			if (err < 0)
   347				goto out1;
   348		}
   349	
   350		ni_lock_dir(old_dir_ni);
   351		ni_lock(old_ni);
   352	
   353		mi_get_ref(&old_dir_ni->mi, &old_name->home);
   354	
   355		/*get pointer to file_name in mft*/
   356		fname = ni_fname_name(old_ni, (struct cpu_str *)&old_name->name_len,
   357				      &old_name->home, &le);
   358		if (!fname) {
   359			err = -EINVAL;
   360			goto out2;
   361		}
   362	
   363		/* Copy fname info from record into new fname */
   364		new_name = (struct ATTR_FILE_NAME *)(new_de + 1);
   365		memcpy(&new_name->dup, &fname->dup, sizeof(fname->dup));
   366	
   367		name_type = paired_name(fname->type);
   368	
   369		/* remove first name from directory */
   370		err = indx_delete_entry(&old_dir_ni->dir, old_dir_ni, old_de + 1,
   371					le16_to_cpu(old_de->key_size), sbi);
   372		if (err)
   373			goto out3;
   374	
   375		/* remove first name from mft */
   376		err = ni_remove_attr_le(old_ni, attr_from_name(fname), le);
   377		if (err)
   378			goto out4;
   379	
   380		le16_add_cpu(&old_ni->mi.mrec->hard_links, -1);
   381		old_ni->mi.dirty = true;
   382	
   383		if (name_type != FILE_NAME_POSIX) {
   384			/* get paired name */
   385			fname = ni_fname_type(old_ni, name_type, &le);
   386			if (fname) {
   387				/* remove second name from directory */
   388				err = indx_delete_entry(&old_dir_ni->dir, old_dir_ni,
   389							fname, fname_full_size(fname),
   390							sbi);
   391				if (err)
   392					goto out5;
   393	
   394				/* remove second name from mft */
   395				err = ni_remove_attr_le(old_ni, attr_from_name(fname),
   396							le);
   397				if (err)
   398					goto out6;
   399	
   400				le16_add_cpu(&old_ni->mi.mrec->hard_links, -1);
   401				old_ni->mi.dirty = true;
   402			}
   403		}
   404	
   405		/* Add new name */
   406		mi_get_ref(&old_ni->mi, &new_de->ref);
   407		mi_get_ref(&ntfs_i(new_dir)->mi, &new_name->home);
   408	
   409		new_de_key_size = le16_to_cpu(new_de->key_size);
   410	
   411		/* insert new name in mft */
   412		err = ni_insert_resident(old_ni, new_de_key_size, ATTR_NAME, NULL, 0,
   413					 &attr, NULL);
   414		if (err)
   415			goto out7;
   416	
   417		attr->res.flags = RESIDENT_FLAG_INDEXED;
   418	
   419		memcpy(Add2Ptr(attr, SIZEOF_RESIDENT), new_name, new_de_key_size);
   420	
   421		le16_add_cpu(&old_ni->mi.mrec->hard_links, 1);
   422		old_ni->mi.dirty = true;
   423	
   424		/* insert new name in directory */
   425		err = indx_insert_entry(&new_dir_ni->dir, new_dir_ni, new_de, sbi,
   426					NULL);
   427		if (err)
   428			goto out8;
   429	
   430		if (IS_DIRSYNC(new_dir))
   431			err = ntfs_sync_inode(old_inode);
   432		else
   433			mark_inode_dirty(old_inode);
   434	
   435		old_dir->i_ctime = old_dir->i_mtime = current_time(old_dir);
   436		if (IS_DIRSYNC(old_dir))
   437			(void)ntfs_sync_inode(old_dir);
   438		else
   439			mark_inode_dirty(old_dir);
   440	
   441		if (old_dir != new_dir) {
   442			new_dir->i_mtime = new_dir->i_ctime = old_dir->i_ctime;
   443			mark_inode_dirty(new_dir);
   444		}
   445	
   446		if (old_inode) {
                    ^^^^^^^^^
If old_inode can be NULL we are toasted.

   447			old_inode->i_ctime = old_dir->i_ctime;
   448			mark_inode_dirty(old_inode);

regards,
dan carpenter