Neils,
Thanks a lot. Will use this for extracting GFID.
Ram
-----Original Message-----
From: Niels de Vos [mailto:[email protected]]
Sent: Tuesday, January 10, 2017 4:26 AM
To: Ankireddypalle Reddy
Cc: Gluster Devel ([email protected]); [email protected]
Subject: Re: [Gluster-devel] Get GFID for a file through libgfapi
On Mon, Jan 09, 2017 at 08:58:07PM +0000, Ankireddypalle Reddy wrote:
> Neils,
> Thanks for pointing to the sample code. The use case is to use
> GFID as a unique key for maintaining indexing information about a file when
> it is being backed up from GlusterFS storage. Extending GFAPI to extract
> GFID for a file would be great.
> As per the example If I need to find GFID for a path
> p1/p2/p3/p4 on a glusterfs volume then should I do a look up for every level?
> LOOKUP (/)->LOOKUP(p1)-> LOOKUP(p2)-> LOOKUP(p3)->
> LOOKUP(p4)
No, that is not required. You can use glfs_h_lookupat() with the full path.
Note that glfs_h_extract_handle() just does a memcpy() of the GFID into the
given (unsigned char*), the format is of 'uuid_t'.
Attached is the modified test that shows the UUID without the need for a lookup
of each component of the directory (a LOOKUP will be done by gfapi if needed).
$ make CFLAGS="-lgfapi -luuid" resolve
cc -lgfapi -luuid resolve.c -o resolve
$ ./resolve storage.example.com media resolve.log
Starting libgfapi_fini
glfs_set_volfile_server : returned 0
glfs_set_logging : returned 0
glfs_init : returned 0
glfs_set_volfile_server : returned 0
glfs_set_logging : returned 0
glfs_init : returned 0
glfs_h_extract_handle : returned 0
UUID of /installation/CentOS-7-x86_64-Everything-1503-01.iso:
b1b20352-c71c-4579-b678-a7a38b0e9a84
glfs_fini : returned 0
End of libgfapi_fini
$ getfattr -n glusterfs.gfid -ehex
/lan/storage.example.com/media/installation/CentOS-7-x86_64-Everything-1503-01.iso
getfattr: Removing leading '/' from absolute path names
# file:
lan/storage.example.com/media/installation/CentOS-7-x86_64-Everything-1503-01.iso
glusterfs.gfid=0xb1b20352c71c4579b678a7a38b0e9a84
HTH,
Niels
>
> Thanks and Regards,
> Ram
>
>
> -----Original Message-----
> From: Niels de Vos [mailto:[email protected]]
> Sent: Monday, January 09, 2017 3:39 PM
> To: Ankireddypalle Reddy
> Cc: Gluster Devel ([email protected]); [email protected]
> Subject: Re: [Gluster-devel] Get GFID for a file through libgfapi
>
> On Mon, Jan 09, 2017 at 05:53:03PM +0000, Ankireddypalle Reddy wrote:
> > Hi,
> > I am trying to extract the GFID for a file through libgfapi
> > interface. When I try to extract the value of extended attribute
> > glusterfs.gfid through libgfapi I get the errorno: 95. This works for FUSE
> > though. Is there a way to extract the GFID for a file through libgfapi.
>
> It seems that this is a case where FUSE handles the xatts special. The
> glusterfs.gfid and glusterfs.gfid.string (VIRTUAL_GFID_XATTR_KEY and
> VIRTUAL_GFID_XATTR_KEY_STR) are specifically handled in
> xlators/mount/fuse/src/fuse-bridge.c.
>
> There is a way to get the GFID, but it probably is rather a cumbersome
> workaround for you. The handle-API is used heavily by NFS-Ganesha
> (because NFS uses filehandles more than filenames), and extracts the
> GFID from the 'struct glfs_object' with glfs_h_extract_handle(). A
> basic example of how to obtain and extract the handle is in
> https://github.com/gluster/glusterfs/blob/master/tests/basic/gfapi/bug
> 1291259.c
>
> Could you explain the need for knowing the GFID in the application? We can
> extend gfapi with fetching the GFID if that would help you.
>
> Niels
>
>
> PS: we have a new [email protected] where external projects can ask
> gfapi related questions. The gluster-devel list tends to be a little heavy on
> traffic for non-Gluster developers.
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