[lustre-discuss] llapi_layout_file_comp_del

[John Bauer]

Andreas,

Thanks for the info.  A related question:  I am using the 
O_LOV_DELAY_CREATE open flag mechanism to open a file and then set the 
composite layout with llapi_layout_file_open().  I was kind of surprised 
this worked.  This ends up opening the file twice and I simply close the 
fd returned from llapi_layout_file_open().  It would seem there should 
be an llapi function such as llapi_layout_set_by_fd() to match the 
llapi_layout_get_by_fd().  I need to use this mechanism to set striping 
for files where the pathname is not necessarily known before the open, 
such as the mkstemps() family of opens.  It also makes it easier to 
handle setting striping for files opened with openat().  It seems it 
would be more straight forward for llapi to work with an fd than a 
pathname if a valid fd already exists. Am I missing an easier way to do 
this?

Thanks,

John

On 7/27/22 16:25, Andreas Dilger wrote:
> The HLD document was written before the feature was implemented, and 
> is outdated.  The lustreapi.h and llapi_layout_file_comp_del.3 man 
> page are correct.  Feel free to update the wiki to use the correct 
> argument list.
>
> I believe that it is possible to delete multiple components that match 
> the <flags> argument (e.g. LCME_FL_NEG|LCME_FL_INIT), but I haven't 
> tested that.
>
>> On Jul 26, 2022, at 14:35, John Bauer <bauerj at iodoctors.com> wrote:
>>
>> Hi all,
>>
>> I would like to use the llapi_layout_file_comp_del() function.  I 
>> have found 2 prototypes in different places.  One has the 3rd 
>> argument, uint32_t flags, and the other doesn't.  I suspect the High 
>> Level Design document is incorrect.  The one line of documentation in 
>> lustreapi.h indicates I could delete multiple components with one 
>> call.  How does one do that? What are the applicable flags?
>>
>> From version 2.12.8 lustreapi.h
>>
>> /**
>> * Delete component(s) by the specified component id or flags.
>> */
>> int  llapi_layout_file_comp_del(const  char  *path, uint32_t  id, 
>> uint32_t  flags);
>>
>>
>> From https://wiki.lustre.org/PFL2_High_Level_Design
>>
>> A new interface llapi_layout_file_comp_del(3) to delete component(s) 
>> by the specified component id (accepting LCME_ID_* wildcards also) 
>> from an existing file:
>>
>> int llapi_layout_file_comp_del(const char *path, uint32_t id);
>>
>> John
>>
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>> lustre-discuss at lists.lustre.org
>> http://lists.lustre.org/listinfo.cgi/lustre-discuss-lustre.org
>
> Cheers, Andreas
> --
> Andreas Dilger
> Lustre Principal Architect
> Whamcloud
>
>
>
>
>
>
>
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