We never allocate the ceph_buffer and buffer separtely, so use a single
constructor.

Disallow put on NULL buffer; make the caller check.
Signed-off-by: NSage Weil <sage@newdream.net>

Signed-off-by: NSage Weil <sage@newdream.net>

We can't fill i_size with rbytes at the fill_file_size stage without
adding additional checks for directories.  Notably, we want st_blocks
to remain 0 on directories so that 'du' still works.

Fill in i_blocks, i_size specially in ceph_getattr instead.
Signed-off-by: NSage Weil <sage@newdream.net>

Inode cache and inode operations.  We also include routines to
incorporate metadata structures returned by the MDS into the client
cache, and some helpers to deal with file capabilities and metadata
leases.  The bulk of that work is done by fill_inode() and
fill_trace().
Signed-off-by: NSage Weil <sage@newdream.net>