On 9/11/2015 2:25 PM, Dongsheng Yang wrote:
> On 09/11/2015 02:18 PM, Sheng Yong wrote:
>> 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.
>
> I mean, if we don't add the code above, what kind of problem
> we would meet?
Then, a new xattr wich length 0 and value NULL, is written to flash, which is useless.
I don't think we should keep this xattr.
>>
>>>> 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.
>
I copied the xattr handler discussion from the other email, so that
we could have it at one place :)
> No, only for POSIX_ACL_DEFAULT|POSIX_ACL_ACCESS currently. Then
> Something like that:
>
> if (type == POSIX_ACL_DEFAULT || type == POSIX_ACL_ACCESS)
> return generic_setxattr(dentry, name, value, size, flags);
Acutally, in my v1 patchset, I did like this. The URL is:
http://lists.infradead.org/pipermail/linux-mtd/2015-March/058451.html
>Security handler is different with acl handler. Please read the
>security_getxattr(), it just return ubifs_getxattr(). That means
>we can use ubifs_getxattr() immediately. So we can remove the
>security_handler for ubifs.
>
>But acl is different, we need to call a special ubifs_get_acl()
>here. Then I found you get the handler by youself in the
>ubifs_get|set_xattr() and call handler->set() by youself.
Right, they are different. I mean using the generic way means
ubifs_[get|set]xattr should be modified.
>
>That's not good idea. Please Just set the handler and call
>generic_setxattr().
But IMO, calling generic_setxattr means we have to add
posix_acl_[access|default]_xattr_handler in ubifs_xattr_handlers, like
const struct xattr_handler *ubifs_xattr_handlers[] = {
&ubifs_xattr_security_handler,
+#ifdef CONFIG_UBIFS_FS_POSIX_ACL
+ &posix_acl_access_xattr_handler,
+ &posix_acl_default_xattr_handler,
+#endif
NULL,
};
then, generic_setxattr() could call posix_acl_***_xattr_handler.set(),
which will call ubifs_set_acl() to do the real setting. Since security
xattr dead code is going to be removed, ubifs_xattr_handlers may go
away too. So I agree with Andreas that if we could add all xattr handlers
in ubifs_xattr_handlers (which means ubifs_[get|set]xattr should be
modified and generic_[get|set]xattr should be set in inode_operations,
e.g ext4, jffs2), it's better to use generic_setxattr. I'm not sure
whether we should convert ubifs to use the xattr handler infrastructure,
like what Andreas said.
thanks,
Sheng
>
> Yang
>>
>> 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)
>>>> {
>>>>
>>>
>>>
>>> .
>>>
>>
>> .
>>
>
>
> .
>
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