[Gluster-devel] empty xlator

[Lluís Pàmies i Juárez]

Hello,

As a proof of concept I'm trying to write a xlator that does nothing, I call it "nop". The code for "nop.c" is simply:

#include "config.h"

#include "call-stub.h"

struct xlator_fops fops = {};

struct xlator_cbks cbks = {};

struct xlator_dumpops dumpops = {};

struct volume_options options[] = {{.key={NULL}},};

int32_t init (xlator_t *this){return 0;}

int fini (xlator_t *this){return 0;}

And I compile it with:

$ gcc -fPIC -D_FILE_OFFSET_BITS=64 -D_GNU_SOURCE -DGF_LINUX_HOST_OS -shared -nostartfiles -lglusterfs -lpthread -I${GFS} -I${GFS}/libglusterfs/src -I${GFS}/contrib/uuid nop.c -o nop.so

Then, if I try a test.vol file like that:

volume test-posix

    type storage/posix

    option directory /home/llpamies/Projects/gluster/test-split/node0-data

end-volume

volume test-nop

    type features/nop

    subvolumes test-posix

end-volume

volume test-cache

  type performance/io-cache

  subvolumes test-nop

end-volume

and mount it with:

$ glusterfs --debug -f test.vol /mount/point

It seems to work fine, doing nothing. However, when used together with the stripe xlator as follows:

volume test-posix0

    type storage/posix

    option directory /home/llpamies/Projects/gluster/test-split/node0-data

end-volume

volume test-posix1

    type storage/posix

    option directory /home/llpamies/Projects/gluster/test-split/node1-data

end-volume

volume test-nop0

    type features/nop

    subvolumes test-posix0

end-volume

volume test-nop1

    type features/nop

    subvolumes test-posix1

end-volume

volume test-stripe

    type cluster/stripe

    subvolumes test-nop0 test-nop1

end-volume

Glusterfs hangs during the first fuse lookup for ".Trash", and /mount/point looks unmounted with ???? permissions etc.

Does it look like some bug in the stripe xlator or is there something fundamentally wrong with the nop xlator?

Thank you,

 

--
Lluís