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  1. 27 Sep, 2016 22 commits
  3. 23 Sep, 2016 3 commits
    • Daniel Wagner's avatar
      xprtrdma: use complete() instead complete_all() · 5690a22d
      Daniel Wagner authored 
      There is only one waiter for the completion, therefore there
is no need to use complete_all(). Let's make that clear by
using complete() instead of complete_all().

The usage pattern of the completion is:

waiter context                          waker context

frwr_op_unmap_sync()
  reinit_completion()
  ib_post_send()
  wait_for_completion()

					frwr_wc_localinv_wake()
					  complete()
Signed-off-by: default avatarDaniel Wagner <daniel.wagner@bmw-carit.de>
Cc: Anna Schumaker <Anna.Schumaker@Netapp.com>
Cc: Trond Myklebust <trond.myklebust@primarydata.com>
Cc: Chuck Lever <chuck.lever@oracle.com>
Cc: linux-nfs@vger.kernel.org
Cc: netdev@vger.kernel.org
Signed-off-by: default avatarAnna Schumaker <Anna.Schumaker@Netapp.com>
      5690a22d
    • Daniel Wagner's avatar
      NFS: cache_lib: use complete() instead of complete_all() · 2a446a5d
      Daniel Wagner authored 
      There is only one waiter for the completion, therefore there
is no need to use complete_all(). Let's make that clear by
using complete() instead of complete_all().

The generic caching code from sunrpc is calling revisit() only once.

The usage pattern of the completion is:

waiter context                          waker context

do_cache_lookup_wait()
  nfs_cache_defer_req_alloc()
    init_completion()
  do_cache_lookup()
  nfs_cache_wait_for_upcall()
    wait_for_completion_timeout()

					nfs_dns_cache_revisit()
					  complete()

  nfs_cache_defer_req_put()
Signed-off-by: default avatarDaniel Wagner <daniel.wagner@bmw-carit.de>
Signed-off-by: default avatarAnna Schumaker <Anna.Schumaker@Netapp.com>
      2a446a5d
    • Daniel Wagner's avatar
      NFS: direct: use complete() instead of complete_all() · 024de8f1
      Daniel Wagner authored 
      There is only one waiter for the completion, therefore there
is no need to use complete_all(). Let's make that clear by
using complete() instead of complete_all().

nfs_file_direct_write() or nfs_file_direct_read() allocated a request
object via nfs_direct_req_alloc(), which initializes the
completion. The request object then is freed later in the exit path.
Between the initialization and the release either
nfs_direct_write_schedule_iovec() resp
nfs_direct_read_schedule_iovec() are called which will asynchronously
process the request. The calling function waits via nfs_direct_wait()
till the async work has been done. Thus there is only one waiter on
the completion.

nfs_direct_pgio_init() and nfs_direct_read_completion() are passed via
function pointers to nfs pageio. The first function does a ref
counting (get_dreq() and put_dreq()) which ensures that
nfs_direct_read_completion() and nfs_direct_read_schedule_iovec() only
call the completion path once.

The usage pattern of the completion is:

waiter context                          waker context

nfs_file_direct_write()
  dreq = nfs_direct_req_alloc()
    init_completion()
  nfs_direct_write_schedule_iovec()
  nfs_direct_wait()
    wait_for_completion_killable()

                                        nfs_direct_write_schedule_work()
                                          nfs_direct_complete()
                                            complete()

nfs_file_direct_read()
  dreq = nfs_direct_req_all()
    init_completion()
  nfs_direct_read_schedule_iovec()
  nfs_direct_wait()
    wait_for_completion_killable()
                                        nfs_direct_read_schedule_iovec()
                                          nfs_direct_complete()
                                            complete()

                                        nfs_direct_read_completion()
                                          nfs_direct_complete()
                                            complete()
Signed-off-by: default avatarDaniel Wagner <daniel.wagner@bmw-carit.de>
Signed-off-by: default avatarAnna Schumaker <Anna.Schumaker@Netapp.com>
      024de8f1
  5. 22 Sep, 2016 12 commits
  7. 20 Sep, 2016 1 commit
  9. 19 Sep, 2016 2 commits
    • David Vrabel's avatar
      sunrpc: fix write space race causing stalls · d48f9ce7
      David Vrabel authored 
      Write space becoming available may race with putting the task to sleep
in xprt_wait_for_buffer_space().  The existing mechanism to avoid the
race does not work.

This (edited) partial trace illustrates the problem:

   [1] rpc_task_run_action: task:43546@5 ... action=call_transmit
   [2] xs_write_space <-xs_tcp_write_space
   [3] xprt_write_space <-xs_write_space
   [4] rpc_task_sleep: task:43546@5 ...
   [5] xs_write_space <-xs_tcp_write_space

[1] Task 43546 runs but is out of write space.

[2] Space becomes available, xs_write_space() clears the
    SOCKWQ_ASYNC_NOSPACE bit.

[3] xprt_write_space() attemts to wake xprt->snd_task (== 43546), but
    this has not yet been queued and the wake up is lost.

[4] xs_nospace() is called which calls xprt_wait_for_buffer_space()
    which queues task 43546.

[5] The call to sk->sk_write_space() at the end of xs_nospace() (which
    is supposed to handle the above race) does not call
    xprt_write_space() as the SOCKWQ_ASYNC_NOSPACE bit is clear and
    thus the task is not woken.

Fix the race by resetting the SOCKWQ_ASYNC_NOSPACE bit in xs_nospace()
so the second call to sk->sk_write_space() calls xprt_write_space().
Suggested-by: default avatarTrond Myklebust <trondmy@primarydata.com>
Signed-off-by: default avatarDavid Vrabel <david.vrabel@citrix.com>
cc: stable@vger.kernel.org # 4.4
Signed-off-by: default avatarAnna Schumaker <Anna.Schumaker@Netapp.com>
      d48f9ce7
    • Jeff Layton's avatar
      pnfs: add a new mechanism to select a layout driver according to an ordered list · ca440c38
      Jeff Layton authored 
      Currently, the layout driver selection code always chooses the first one
from the list. That's not really ideal however, as the server can send
the list of layout types in any order that it likes. It's up to the
client to select the best one for its needs.

This patch adds an ordered list of preferred driver types and has the
selection code sort the list of available layout drivers according to it.
Any unrecognized layout type is sorted to the end of the list.

For now, the order of preference is hardcoded, but it should be possible
to make this configurable in the future.
Signed-off-by: default avatarJeff Layton <jlayton@redhat.com>
Reviewed-by: default avatarJ. Bruce Fields <bfields@fieldses.org>
Signed-off-by: default avatarAnna Schumaker <Anna.Schumaker@Netapp.com>
      ca440c38
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