Hi, bug 1093324 has been opened and we have identified the following cause: 1. an NFS-client does a LOOKUP of a directory on a volume 2. the NFS-client receives a filehandle (contains volume-id + GFID) 3. add-brick is executed, but the new brick does not have any directories yet 4. the NFS-client creates a new file in the directory, this request is in the format or <filehandle>/<filename>, <filehandle> was received in step 2 5. the NFS-server does a LOOKUP on the parent directory identified by the filehandle - nameless LOOKUP, only GFID is known 6. the old brick(s) return successfully 7. the new brick returns ESTALE 8. the NFS-server returns ESTALE to the NFS-client In this case, the NFS-client should not receive an ESTALE. There is also no ESTALE error passed to the client when this procedure is done over FUSE or samba/libgfapi. Selfhealing a directory entry based only on a GFID is not always possible. Files do not have a unique filename (hardlinks), so it is not trivial to find a filename for a GFID (expensive operation, and the result could be a list). However, for a directory this is simpler. A directory is not hardlink'd in the .glusterfs directory, directories are maintained as symbolic-links. This makes it possible to find the name of a directory, when only the GFID is known. Currently DHT is not able to selfheal directories on a nameless LOOKUP. I think that it should be possible to change this, and to fix the ESTALE returned by the NFS-server. At least two changes would be needed, and this is where I would like to hear opinions from others about it: - The posix-xlator should be able to return the directory name when a GFID is given. This can be part of the LOOKUP-reply (dict), and that would add a readlink() syscall for each nameless LOOKUP that finds a directory. Or (suggested by Pranith) add a virtual xattr and handle this specific request with an additional FGETXATTR call. - DHT should selfheal the directory when at least one ESTALE is returned by the bricks. When all bricks return ESTALE, the ESTALE is valid and should be passed on to the upper layers (NFS-server -> NFS-client). I've added Venkatesh on CC, his patch http://review.gluster.org/74930 is in the review queue and seems to be a little related to this. Although that change does not address the problem in this email, as Susant (+CC) pointed out earlier today. Thanks, Niels _______________________________________________ Gluster-devel mailing list Gluster-devel@xxxxxxxxxxx http://supercolony.gluster.org/mailman/listinfo/gluster-devel
