[CRIU] [PATCH 10/17] fsnotify: Add fanotify restore

[Pavel Emelyanov]

On 12/24/2012 06:02 PM, Cyrill Gorcunov wrote:
> On Mon, Dec 24, 2012 at 05:56:11PM +0400, Pavel Emelyanov wrote:
>> On 12/24/2012 05:50 PM, Cyrill Gorcunov wrote:
>>> On Mon, Dec 24, 2012 at 05:32:12PM +0400, Pavel Emelyanov wrote:
>>>> On 12/11/2012 01:34 AM, Cyrill Gorcunov wrote:
>>>>>
>>>>> The idea is the same as for inotify -- just open
>>>>> notification descriptor and hook paths on.
>>>>>
>>>>> Signed-off-by: Cyrill Gorcunov <gorcunov at openvz.org>
>>>>> ---
>>>>>  fsnotify.c | 91 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++--
>>>>>  1 file changed, 89 insertions(+), 2 deletions(-)
>>>>>
>>>>> +	/*
>>>>> +	 * Note we use OR'ed iwe->wd here, since for fanotify it
>>>>> +	 * provides additional flags for the mark.
>>>>> +	 */
>>>>> +	flags |= iwe->wd;
>>>>
>>>> I don't understand this. Kernel denies putting any flags but known into
>>>> sys_fanotify_mark.
>>>
>>> wd consist of additional flags associated with mark, ie "mflags" field
>>
>> WHAT?! How did this happen, I have missed this from the set.
> 
> This comes from parsing procfs
> 
> 					entry.fsy.type = FSNOTIFY_TYPE__FANOTIFY;
> 					ret = sscanf(&str[13],
> 						     "%lx sdev:%x "
> 						     "mflags:%x mask:%x ignored_mask:%x "
> 						     "fhandle-bytes:%x fhandle-type:%x "
> 						     "f_handle: %n",
> 						     &entry.fsy.i_ino, &entry.fsy.s_dev,
> -->						     &entry.fsy.wd, &entry.fsy.mask, &entry.fsy.ignored_mask,

:\ OK... Don't put _mask_ into _wd_ field. Add another one.

> 						     &entry.fsy.f_handle->bytes, &entry.fsy.f_handle->type,
> 						     &hoff);
> 
> which is because
> 
> commit e6dbcafb744ab94a94142a6e721e16330397fad8
> Author: Cyrill Gorcunov <gorcunov at openvz.org>
> Date:   Mon Dec 17 16:05:16 2012 -0800
> 
>     fs, fanotify: add @mflags field to fanotify output
>     
>     The kernel keeps FAN_MARK_IGNORED_SURV_MODIFY bit separately from
>     fsnotify_mark::mask|ignored_mask thus put it in @mflags (mark flags)
>     field so the user-space reader will be able to detect if such bit were
>     used on mark creation procedure.
>     
>      | pos:     0
>      | flags:   04002
>      | fanotify flags:10 event-flags:0
>      | fanotify mnt_id:12 mflags:40 mask:38 ignored_mask:40000003
>      | fanotify ino:4f969 sdev:800013 mflags:0 mask:3b ignored_mask:40000000 fhandle-bytes:8 fhandle-type:1 f_handle:69f90400c275b5b4
> 
> 	Cyrill
> .
>