Skip to content

cloud-kernel
cloud-kernel

openanolis / cloud-kernel
1 年多 前同步成功

通知 165
Star 36
Fork 7
cloud-kernel
cloud-kernel
切换分支/标签
  1. 11 3月, 2011 1 次提交
    • T
      SUNRPC: Close a race in __rpc_wait_for_completion_task() · bf294b41
      由 Trond Myklebust 提交于 
      Although they run as rpciod background tasks, under normal operation
(i.e. no SIGKILL), functions like nfs_sillyrename(), nfs4_proc_unlck()
and nfs4_do_close() want to be fully synchronous. This means that when we
exit, we want all references to the rpc_task to be gone, and we want
any dentry references etc. held by that task to be released.

For this reason these functions call __rpc_wait_for_completion_task(),
followed by rpc_put_task() in the expectation that the latter will be
releasing the last reference to the rpc_task, and thus ensuring that the
callback_ops->rpc_release() has been called synchronously.

This patch fixes a race which exists due to the fact that
rpciod calls rpc_complete_task() (in order to wake up the callers of
__rpc_wait_for_completion_task()) and then subsequently calls
rpc_put_task() without ensuring that these two steps are done atomically.

In order to avoid adding new spin locks, the patch uses the existing
waitqueue spin lock to order the rpc_task reference count releases between
the waiting process and rpciod.
The common case where nobody is waiting for completion is optimised for by
checking if the RPC_TASK_ASYNC flag is cleared and/or if the rpc_task
reference count is 1: in those cases we drop trying to grab the spin lock,
and immediately free up the rpc_task.

Those few processes that need to put the rpc_task from inside an
asynchronous context and that do not care about ordering are given a new
helper: rpc_put_task_async().
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>
      bf294b41
  3. 26 1月, 2011 1 次提交
  5. 12 1月, 2011 2 次提交
  7. 11 1月, 2011 2 次提交
  9. 07 1月, 2011 5 次提交
  11. 05 1月, 2011 2 次提交
  13. 18 12月, 2010 1 次提交
    • N
      sunrpc: remove xpt_pool · 7c96aef7
      由 NeilBrown 提交于 
      The xpt_pool field is only used for reporting BUGs.
And it isn't used correctly.

In particular, when it is cleared in svc_xprt_received before
XPT_BUSY is cleared, there is no guarantee that either the
compiler or the CPU might not re-order to two assignments, just
setting xpt_pool to NULL after XPT_BUSY is cleared.

If a different cpu were running svc_xprt_enqueue at this moment,
it might see XPT_BUSY clear and then xpt_pool non-NULL, and
so BUG.

This could be fixed by calling
  smp_mb__before_clear_bit()
before the clear_bit.  However as xpt_pool isn't really used,
it seems safest to simply remove xpt_pool.

Another alternate would be to change the clear_bit to
clear_bit_unlock, and the test_and_set_bit to test_and_set_bit_lock.
Signed-off-by: NNeilBrown <neilb@suse.de>
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>
      7c96aef7
  15. 17 12月, 2010 2 次提交
  17. 03 11月, 2010 1 次提交
  19. 25 10月, 2010 1 次提交
  21. 24 10月, 2010 1 次提交
  23. 02 10月, 2010 9 次提交
  25. 30 9月, 2010 1 次提交
    • S
      sunrpc: fix up rpcauth_remove_module section mismatch · c135e84a
      由 Stephen Rothwell 提交于 
      On Wed, 29 Sep 2010 14:02:38 +1000 Stephen Rothwell <sfr@canb.auug.org.au> wrote:
>
> After merging the final tree, today's linux-next build (powerpc
> ppc44x_defconfig) produced tis warning:
>
> WARNING: net/sunrpc/sunrpc.o(.init.text+0x110): Section mismatch in reference from the function init_sunrpc() to the function .exit.text:rpcauth_remove_module()
> The function __init init_sunrpc() references
> a function __exit rpcauth_remove_module().
> This is often seen when error handling in the init function
> uses functionality in the exit path.
> The fix is often to remove the __exit annotation of
> rpcauth_remove_module() so it may be used outside an exit section.
>
> Probably caused by commit 2f72c9b7
> ("sunrpc: The per-net skeleton").

This actually causes a build failure on a sparc32 defconfig build:

`rpcauth_remove_module' referenced in section `.init.text' of net/built-in.o: defined in discarded section `.exit.text' of net/built-in.o

I applied the following patch for today:

Fixes:

`rpcauth_remove_module' referenced in section `.init.text' of net/built-in.o: defined in discarded section `.exit.text' of net/built-in.o
Signed-off-by: NStephen Rothwell <sfr@canb.auug.org.au>
Acked-by: NPavel Emelyanov <xemul@openvz.org>
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>
      c135e84a
  27. 27 9月, 2010 5 次提交
  29. 22 9月, 2010 3 次提交
  31. 17 9月, 2010 1 次提交
  33. 13 9月, 2010 1 次提交
  35. 08 9月, 2010 1 次提交
    • N
      sunrpc/cache: allow threads to block while waiting for cache update. · f16b6e8d
      由 NeilBrown 提交于 
      The current practice of waiting for cache updates by queueing the
whole request to be retried has (at least) two problems.

1/ With NFSv4, requests can be quite complex and re-trying a whole
  request when a later part fails should only be a last-resort, not a
  normal practice.

2/ Large requests, and in particular any 'write' request, will not be
  queued by the current code and doing so would be undesirable.

In many cases only a very sort wait is needed before the cache gets
valid data.

So, providing the underlying transport permits it by setting
 ->thread_wait,
arrange to wait briefly for an upcall to be completed (as reflected in
the clearing of CACHE_PENDING).
If the short wait was not long enough and CACHE_PENDING is still set,
fall back on the old approach.

The 'thread_wait' value is set to 5 seconds when there are spare
threads, and 1 second when there are no spare threads.

These values are probably much higher than needed, but will ensure
some forward progress.

Note that as we only request an update for a non-valid item, and as
non-valid items are updated in place it is extremely unlikely that
cache_check will return -ETIMEDOUT.  Normally cache_defer_req will
sleep for a short while and then find that the item is_valid.
Signed-off-by: NNeilBrown <neilb@suse.de>
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>
      f16b6e8d