ceph: add get_parent() NFS export callback

The callback uses LOOKUPPARENT MDS request to find parent.

Signed-off-by: Yan, Zheng <zheng.z.yan@intel.com>
Reviewed-by: Sage Weil <sage@inktank.com>
ceph: fix ceph_fh_to_parent()

ceph_fh_to_parent() returns dentry that corresponds to the 'ino' field
of struct ceph_nfs_confh. This is wrong, it should return dentry that
corresponds to the 'parent_ino' field.

Signed-off-by: Yan, Zheng <zheng.z.yan@intel.com>
Reviewed-by: Sage Weil <sage@inktank.com>
ceph: add get_name() NFS export callback

Use the newly introduced LOOKUPNAME MDS request to connect child
inode to its parent directory.

Signed-off-by: Yan, Zheng <zheng.z.yan@intel.com>
Reviewed-by: Sage Weil <sage@inktank.com>
ceph: print inode number for LOOKUPINO request

Signed-off-by: Yan, Zheng <zheng.z.yan@intel.com>
Reviewed-by: Sage Weil <sage@inktank.com>
vfs: Make __d_materialise_dentry() set the materialised dentry name correctly

Make __d_materialise_dentry() set the materialised dentry name correctly by
flipping the arguments to switch_names().

switch_names() is lazy: if both names are internal to their dentries, it'll
overwrite that of the first dentry with that of the second, and won't update
that of the second.

In the case of __d_materialise_dentry(), the second is an already extant
anonymous dentry that we want to insert into the tree in place of the dentry we
just looked up[*].  However, the dentry we just looked up carries the name we
actually want to use.

[*] This is used by NFS to join a mount of a subtree into a mount of a tree
nearer the root when the two meet, where both mounts share a superblock and
thus a set of dentries.

Signed-off-by: David Howells <dhowells@redhat.com>
ceph: make sure write caps are registered with auth MDS

Only auth MDS can issue write caps to clients, so don't consider
write caps registered with non-auth MDS as valid.

Signed-off-by: Yan, Zheng <zheng.z.yan@intel.com>
ceph: update i_max_size even if inode version does not change

handle following sequence of events:
 - client releases a inode with i_max_size > 0. The release message
   is queued. (is not sent to the auth MDS)
 - a 'lookup' request reply from non-auth MDS returns the same inode.
 - client opens the inode in write mode. The version of inode trace
   in 'open' request reply is equal to the cached inode's version.
 - client requests new max size. The MDS ignores the request because
   it does not affect client's write range

Signed-off-by: Yan, Zheng <zheng.z.yan@intel.com>
Reviewed-by: Sage Weil <sage@inktank.com>
ceph: use fl->fl_type to decide flock operation

VFS does not directly pass flock's operation code to filesystem's
flock callback. It translates the operation code to the form how
posix lock's parameters are presented.

Signed-off-by: Yan, Zheng <zheng.z.yan@intel.com>
ceph: forbid mandatory file lock

Signed-off-by: Yan, Zheng <zheng.z.yan@intel.com>
ceph: use fl->fl_file as owner identifier of flock and posix lock

flock and posix lock should use fl->fl_file instead of process ID
as owner identifier. (posix lock uses fl->fl_owner. fl->fl_owner
is usually equal to fl->fl_file, but it also can be a customized
value). The process ID of who holds the lock is just for F_GETLK
fcntl(2).

The fix is rename the 'pid' fields of struct ceph_mds_request_args
and struct ceph_filelock to 'owner', rename 'pid_namespace' fields
to 'pid'. Assign fl->fl_file to the 'owner' field of lock messages.
We also set the most significant bit of the 'owner' field. MDS can
use that bit to distinguish between old and new clients.

The MDS counterpart of this patch modifies the flock code to not
take the 'pid_namespace' into consideration when checking conflict
locks.

Signed-off-by: Yan, Zheng <zheng.z.yan@intel.com>