afs: Calculate i_blocks based on file size

While it's not possible to give an accurate number for the blocks
used on the server, populate i_blocks based on the file size so
that 'du' can give a reasonable estimate.

The value is rounded up to 1K granularity, for consistency with
what other AFS clients report, and the servers' 1K usage quota
unit.  Note that the value calculated by 'du' at the root of a
volume can still be slightly lower than the quota usage on the
server, as 0-length files are charged 1 quota block, but are
reported as occupying 0 blocks.  Again, this is consistent with
other AFS clients.

Signed-off-by: Marc Dionne <marc.dionne@auristor.com>
Signed-off-by: David Howells <dhowells@redhat.com>

fs/afs/inode.c

@@ -111,7 +111,11 @@ static int afs_inode_init_from_status(struct afs_vnode *vnode, struct key *key,
 		return afs_protocol_error(NULL, -EBADMSG, afs_eproto_file_type);
 	}
 
-	inode->i_blocks		= 0;
+	/*
+	 * Estimate 512 bytes  blocks used, rounded up to nearest 1K
+	 * for consistency with other AFS clients.
+	 */
+	inode->i_blocks		= ((i_size_read(inode) + 1023) >> 10) << 1;
 	vnode->invalid_before	= vnode->status.data_version;
 
 	read_sequnlock_excl(&vnode->cb_lock);