Re: [RFC PATCH v3 3/5] UBIFS: ACL: handle ACL through xattr

[Sheng Yong <shengyong1@huawei.com>]

Hi, Dongsheng

On 9/11/2015 1:01 PM, Dongsheng Yang wrote:
> On 09/11/2015 05:09 PM, Sheng Yong wrote:
[...]
> 
> Why move it? If you just want to use them before the definitions,
> Just declare them before using.

OK.
>>   int ubifs_do_setxattr(struct inode *host, const char *name,
>>                 const void *value, size_t size, int flags)
>>   {
>> @@ -348,7 +462,19 @@ int ubifs_do_setxattr(struct inode *host, const char *name,
>>           goto out_free;
>>       }
>>
>> +#ifdef CONFIG_UBIFS_FS_POSIX_ACL
>> +    if (size == 0) {
>> +        ubifs_assert(inode->i_nlink == 1);
>> +        clear_nlink(inode);
>> +        err = remove_xattr(c, host, inode, &nm);
>> +        if (err)
>> +            set_nlink(inode, 1);
>> +        iput(inode);
>> +        goto out_free;
>> +    }
>> +#endif
> 
> Is there a testcase for it?

I test `setfacl -b/-k'. I don't know how setfacl is implemented. But for ACL_TYPE_ACCESS,
ubifs_setxattr() is called with size = 0 and value = NULL; while for ACL_TYPE_DEFAULT,
ubifs_removexattr() is called.

>>       err = change_xattr(c, host, inode, value, size);
>> +
>>       iput(inode);
>>
>>   out_free:
>> @@ -359,6 +485,9 @@ out_free:
>>   int ubifs_setxattr(struct dentry *dentry, const char *name,
>>              const void *value, size_t size, int flags)
>>   {
>> +#ifdef CONFIG_UBIFS_FS_POSIX_ACL
>> +    const struct xattr_handler *handler;
>> +#endif
>>       struct qstr nm = QSTR_INIT(name, strlen(name));
>>       int type;
>>
>> @@ -369,6 +498,16 @@ int ubifs_setxattr(struct dentry *dentry, const char *name,
>>       if (type < 0)
>>           return type;
>>
>> +#ifdef CONFIG_UBIFS_FS_POSIX_ACL
>> +    if (type == POSIX_ACL_DEFAULT || type == POSIX_ACL_ACCESS) {
>> +        if (type == POSIX_ACL_DEFAULT)
>> +            handler = &posix_acl_default_xattr_handler;
>> +        if (type == POSIX_ACL_ACCESS)
>> +            handler = &posix_acl_access_xattr_handler;
>> +        return handler->set(dentry, name, value, size, flags,
>> +                    handler->flags);
>> +    }
>> +#endif
> 
> What about setting sb->s_xattr and calling generic_setxattr() here?

I have no idea if we should do this :(
If we do, I think, we should call generic functions for all xattr.

thanks,
Sheng

>>       return ubifs_do_setxattr(d_inode(dentry), name, value, size, flags);
>>   }
>>
>> @@ -428,6 +567,9 @@ out_unlock:
>>   ssize_t ubifs_getxattr(struct dentry *dentry, const char *name,
>>                  void *value, size_t size)
>>   {
>> +#ifdef CONFIG_UBIFS_FS_POSIX_ACL
>> +    const struct xattr_handler *handler;
>> +#endif
>>       struct qstr nm = QSTR_INIT(name, strlen(name));
>>       int type;
>>
>> @@ -438,6 +580,16 @@ ssize_t ubifs_getxattr(struct dentry *dentry, const char *name,
>>       if (type < 0)
>>           return type;
>>
>> +#ifdef CONFIG_UBIFS_FS_POSIX_ACL
>> +    if (type == POSIX_ACL_DEFAULT || type == POSIX_ACL_ACCESS) {
>> +        if (type == POSIX_ACL_DEFAULT)
>> +            handler = &posix_acl_default_xattr_handler;
>> +        if (type == POSIX_ACL_ACCESS)
>> +            handler = &posix_acl_access_xattr_handler;
>> +        return handler->get(dentry, name, value, size,
>> +                    handler->flags);
>> +    }
>> +#endif
> 
> Ditto
> 
> Thanx
> Yang
>>       return ubifs_do_getxattr(d_inode(dentry), name, value, size);
>>   }
>>
>> @@ -505,95 +657,6 @@ ssize_t ubifs_listxattr(struct dentry *dentry, char *buffer, size_t size)
>>       return written;
>>   }
>>
>> -static int remove_xattr(struct ubifs_info *c, struct inode *host,
>> -            struct inode *inode, const struct qstr *nm)
>> -{
>> -    int err;
>> -    struct ubifs_inode *host_ui = ubifs_inode(host);
>> -    struct ubifs_inode *ui = ubifs_inode(inode);
>> -    struct ubifs_budget_req req = { .dirtied_ino = 2, .mod_dent = 1,
>> -                .dirtied_ino_d = ALIGN(host_ui->data_len, 8) };
>> -
>> -    ubifs_assert(ui->data_len == inode->i_size);
>> -
>> -    err = ubifs_budget_space(c, &req);
>> -    if (err)
>> -        return err;
>> -
>> -    mutex_lock(&host_ui->ui_mutex);
>> -    host->i_ctime = ubifs_current_time(host);
>> -    host_ui->xattr_cnt -= 1;
>> -    host_ui->xattr_size -= CALC_DENT_SIZE(nm->len);
>> -    host_ui->xattr_size -= CALC_XATTR_BYTES(ui->data_len);
>> -    host_ui->xattr_names -= nm->len;
>> -
>> -    err = ubifs_jnl_delete_xattr(c, host, inode, nm);
>> -    if (err)
>> -        goto out_cancel;
>> -    mutex_unlock(&host_ui->ui_mutex);
>> -
>> -    ubifs_release_budget(c, &req);
>> -    return 0;
>> -
>> -out_cancel:
>> -    host_ui->xattr_cnt += 1;
>> -    host_ui->xattr_size += CALC_DENT_SIZE(nm->len);
>> -    host_ui->xattr_size += CALC_XATTR_BYTES(ui->data_len);
>> -    mutex_unlock(&host_ui->ui_mutex);
>> -    ubifs_release_budget(c, &req);
>> -    make_bad_inode(inode);
>> -    return err;
>> -}
>> -
>> -int ubifs_removexattr(struct dentry *dentry, const char *name)
>> -{
>> -    struct inode *inode, *host = d_inode(dentry);
>> -    struct ubifs_info *c = host->i_sb->s_fs_info;
>> -    struct qstr nm = QSTR_INIT(name, strlen(name));
>> -    struct ubifs_dent_node *xent;
>> -    union ubifs_key key;
>> -    int err;
>> -
>> -    dbg_gen("xattr '%s', ino %lu ('%pd')", name,
>> -        host->i_ino, dentry);
>> -    ubifs_assert(mutex_is_locked(&host->i_mutex));
>> -
>> -    err = check_namespace(&nm);
>> -    if (err < 0)
>> -        return err;
>> -
>> -    xent = kmalloc(UBIFS_MAX_XENT_NODE_SZ, GFP_NOFS);
>> -    if (!xent)
>> -        return -ENOMEM;
>> -
>> -    xent_key_init(c, &key, host->i_ino, &nm);
>> -    err = ubifs_tnc_lookup_nm(c, &key, xent, &nm);
>> -    if (err) {
>> -        if (err == -ENOENT)
>> -            err = -ENODATA;
>> -        goto out_free;
>> -    }
>> -
>> -    inode = iget_xattr(c, le64_to_cpu(xent->inum));
>> -    if (IS_ERR(inode)) {
>> -        err = PTR_ERR(inode);
>> -        goto out_free;
>> -    }
>> -
>> -    ubifs_assert(inode->i_nlink == 1);
>> -    clear_nlink(inode);
>> -    err = remove_xattr(c, host, inode, &nm);
>> -    if (err)
>> -        set_nlink(inode, 1);
>> -
>> -    /* If @i_nlink is 0, 'iput()' will delete the inode */
>> -    iput(inode);
>> -
>> -out_free:
>> -    kfree(xent);
>> -    return err;
>> -}
>> -
>>   static size_t security_listxattr(struct dentry *d, char *list, size_t list_size,
>>                    const char *name, size_t name_len, int flags)
>>   {
>>
> 
> 
> .
>