tree 2d6963451a068915f818c72e85db55337bdf7b06
parent d2d33839b71df3907be6ad6c45db0464409d828d
author Jeff Layton <jlayton@kernel.org> 1645875183 -0500
committer Jeff Layton <jlayton@kernel.org> 1647886853 -0400

ceph: add new mount option to enable sparse reads

Add a new mount option that has the client issue sparse reads instead of
normal ones. The callers now preallocate an sparse extent buffer that
the libceph receive code can populate and hand back after the operation
completes.

After a successful sparse read, we can't use the req->r_result value to
determine the amount of data "read", so instead we set the received
length to be from the end of the last extent in the buffer. Any
interstitial holes will have been filled by the receive code.

Signed-off-by: Jeff Layton <jlayton@kernel.org>