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  1. 25 Jul, 2022 2 commits
  3. 23 Jul, 2022 1 commit
  5. 07 Jun, 2022 1 commit
    • Scott Mayhew's avatar
      sunrpc: set cl_max_connect when cloning an rpc_clnt · 30479125
      Scott Mayhew authored 
      
If the initial attempt at trunking detection using the krb5i auth flavor
fails with -EACCES, -NFS4ERR_CLID_INUSE, or -NFS4ERR_WRONGSEC, then the
NFS client tries again using auth_sys, cloning the rpc_clnt in the
process.  If this second attempt at trunking detection succeeds, then
the resulting nfs_client->cl_rpcclient winds up having cl_max_connect=0
and subsequent attempts to add additional transport connections to the
rpc_clnt will fail with a message similar to the following being logged:

[502044.312640] SUNRPC: reached max allowed number (0) did not add
transport to server: 192.168.122.3
Signed-off-by: default avatarScott Mayhew <smayhew@redhat.com>
Fixes: dc48e0ab

 ("SUNRPC enforce creation of no more than max_connect xprts")
Signed-off-by: default avatarAnna Schumaker <Anna.Schumaker@Netapp.com>
      30479125
  7. 07 May, 2022 2 commits
  9. 29 Apr, 2022 1 commit
  11. 22 Apr, 2022 1 commit
  13. 07 Apr, 2022 3 commits
  15. 30 Mar, 2022 1 commit
    • NeilBrown's avatar
      SUNRPC: handle malloc failure in ->request_prepare · eb07d5a4
      NeilBrown authored 
      
If ->request_prepare() detects an error, it sets ->rq_task->tk_status.
This is easy for callers to ignore.
The only caller is xprt_request_enqueue_receive() and it does ignore the
error, as does call_encode() which calls it.  This can result in a
request being queued to receive a reply without an allocated receive buffer.

So instead of setting rq_task->tk_status, return an error, and store in
->tk_status only in call_encode();

The call to xprt_request_enqueue_receive() is now earlier in
call_encode(), where the error can still be handled.
Signed-off-by: default avatarNeilBrown <neilb@suse.de>
Signed-off-by: default avatarTrond Myklebust <trond.myklebust@hammerspace.com>
      eb07d5a4
  17. 24 Mar, 2022 1 commit
  19. 13 Mar, 2022 3 commits
    • NeilBrown's avatar
      NFSv4: keep state manager thread active if swap is enabled · 4dc73c67
      NeilBrown authored 
      
If we are swapping over NFSv4, we may not be able to allocate memory to
start the state-manager thread at the time when we need it.
So keep it always running when swap is enabled, and just signal it to
start.

This requires updating and testing the cl_swapper count on the root
rpc_clnt after following all ->cl_parent links.
Signed-off-by: default avatarNeilBrown <neilb@suse.de>
Signed-off-by: default avatarTrond Myklebust <trond.myklebust@hammerspace.com>
      4dc73c67
    • NeilBrown's avatar
      SUNRPC: improve 'swap' handling: scheduling and PF_MEMALLOC · 8db55a03
      NeilBrown authored 
      
rpc tasks can be marked as RPC_TASK_SWAPPER.  This causes GFP_MEMALLOC
to be used for some allocations.  This is needed in some cases, but not
in all where it is currently provided, and in some where it isn't
provided.

Currently *all* tasks associated with a rpc_client on which swap is
enabled get the flag and hence some GFP_MEMALLOC support.

GFP_MEMALLOC is provided for ->buf_alloc() but only swap-writes need it.
However xdr_alloc_bvec does not get GFP_MEMALLOC - though it often does
need it.

xdr_alloc_bvec is called while the XPRT_LOCK is held.  If this blocks,
then it blocks all other queued tasks.  So this allocation needs
GFP_MEMALLOC for *all* requests, not just writes, when the xprt is used
for any swap writes.

Similarly, if the transport is not connected, that will block all
requests including swap writes, so memory allocations should get
GFP_MEMALLOC if swap writes are possible.

So with this patch:
 1/ we ONLY set RPC_TASK_SWAPPER for swap writes.
 2/ __rpc_execute() sets PF_MEMALLOC while handling any task
    with RPC_TASK_SWAPPER set, or when handling any task that
    holds the XPRT_LOCKED lock on an xprt used for swap.
    This removes the need for the RPC_IS_SWAPPER() test
    in ->buf_alloc handlers.
 3/ xprt_prepare_transmit() sets PF_MEMALLOC after locking
    any task to a swapper xprt.  __rpc_execute() will clear it.
 3/ PF_MEMALLOC is set for all the connect workers.

Reviewed-by: Chuck Lever <chuck.lever@oracle.com> (for xprtrdma parts)
Signed-off-by: default avatarNeilBrown <neilb@suse.de>
Signed-off-by: default avatarTrond Myklebust <trond.myklebust@hammerspace.com>
      8db55a03
    • NeilBrown's avatar
      SUNRPC/auth: async tasks mustn't block waiting for memory · a41b05ed
      NeilBrown authored 
      
When memory is short, new worker threads cannot be created and we depend
on the minimum one rpciod thread to be able to handle everything.  So it
must not block waiting for memory.

mempools are particularly a problem as memory can only be released back
to the mempool by an async rpc task running.  If all available workqueue
threads are waiting on the mempool, no thread is available to return
anything.

lookup_cred() can block on a mempool or kmalloc - and this can cause
deadlocks.  So add a new RPCAUTH_LOOKUP flag for async lookups and don't
block on memory.  If the -ENOMEM gets back to call_refreshresult(), wait
a short while and try again.  HZ>>4 is chosen as it is used elsewhere
for -ENOMEM retries.
Signed-off-by: default avatarNeilBrown <neilb@suse.de>
Signed-off-by: default avatarTrond Myklebust <trond.myklebust@hammerspace.com>
      a41b05ed
  21. 25 Feb, 2022 1 commit
  23. 13 Jan, 2022 1 commit
  25. 20 Oct, 2021 1 commit
  27. 27 Aug, 2021 2 commits
  29. 09 Aug, 2021 3 commits
  31. 08 Jul, 2021 4 commits
  33. 20 May, 2021 1 commit
    • NeilBrown's avatar
      SUNRPC in case of backlog, hand free slots directly to waiting task · e877a88d
      NeilBrown authored 
      If sunrpc.tcp_max_slot_table_entries is small and there are tasks
on the backlog queue, then when a request completes it is freed and the
first task on the queue is woken.  The expectation is that it will wake
and claim that request.  However if it was a sync task and the waiting
process was killed at just that moment, it will wake and NOT claim the
request.

As long as TASK_CONGESTED remains set, requests can only be claimed by
tasks woken from the backlog, and they are woken only as requests are
freed, so when a task doesn't claim a request, no other task can ever
get that request until TASK_CONGESTED is cleared.  Each time this
happens the number of available requests is decreased by one.

With a sufficiently high workload and sufficiently low setting of
max_slot (16 in the case where this was seen), TASK_CONGESTED can remain
set for an extended period, and the above scenario (of a process being
killed just as its task was woken) can repeat until no requests can be
allocated.  Then traffic stops.

This patch addresses the problem by introducing a positive handover of a
request from a completing task to a backlog task - the request is never
freed when there is a backlog.

When a task is woken it might not already have a request attached in
which case it is *not* freed (as with current code) but is initialised
(if needed) and used.  If it isn't used it will eventually be freed by
rpc_exit_task().  xprt_release() is enhanced to be able to correctly
release an uninitialised request.

Fixes: ba60eb25

 ("SUNRPC: Fix a livelock problem in the xprt->backlog queue")
Signed-off-by: default avatarNeilBrown <neilb@suse.de>
Signed-off-by: default avatarTrond Myklebust <trond.myklebust@hammerspace.com>
      e877a88d
  35. 01 May, 2021 1 commit
    • Baptiste Lepers's avatar
      sunrpc: Fix misplaced barrier in call_decode · f8f7e0fb
      Baptiste Lepers authored 
      Fix a misplaced barrier in call_decode. The struct rpc_rqst is modified
as follows by xprt_complete_rqst:

req->rq_private_buf.len = copied;
/* Ensure all writes are done before we update */
/* req->rq_reply_bytes_recvd */
smp_wmb();
req->rq_reply_bytes_recvd = copied;

And currently read as follows by call_decode:

smp_rmb(); // misplaced
if (!req->rq_reply_bytes_recvd)
   goto out;
req->rq_rcv_buf.len = req->rq_private_buf.len;

This patch places the smp_rmb after the if to ensure that
rq_reply_bytes_recvd and rq_private_buf.len are read in order.

Fixes: 9ba82886

 ("SUNRPC: Don't try to parse incomplete RPC messages")
Signed-off-by: default avatarBaptiste Lepers <baptiste.lepers@gmail.com>
Signed-off-by: default avatarTrond Myklebust <trond.myklebust@hammerspace.com>
      f8f7e0fb
  37. 14 Apr, 2021 1 commit
    • Chuck Lever's avatar
      SUNRPC: Move fault injection call sites · 7638e0bf
      Chuck Lever authored 
      I've hit some crashes that occur in the xprt_rdma_inject_disconnect
path. It appears that, for some provides, rdma_disconnect() can
take so long that the transport can disconnect and release its
hardware resources while rdma_disconnect() is still running,
resulting in a UAF in the provider.

The transport's fault injection method may depend on the stability
of transport data structures. That means it needs to be invoked
only from contexts that hold the transport write lock.

Fixes: 4a068258

 ("SUNRPC: Transport fault injection")
Signed-off-by: default avatarChuck Lever <chuck.lever@oracle.com>
Signed-off-by: default avatarTrond Myklebust <trond.myklebust@hammerspace.com>
      7638e0bf
  39. 02 Dec, 2020 1 commit
    • Trond Myklebust's avatar
      SUNRPC: Clean up the handling of page padding in rpc_prepare_reply_pages() · 9ed5af26
      Trond Myklebust authored 
      rpc_prepare_reply_pages() currently expects the 'hdrsize' argument to
contain the length of the data that we expect to want placed in the head
kvec plus a count of 1 word of padding that is placed after the page data.
This is very confusing when trying to read the code, and sometimes leads
to callers adding an arbitrary value of '1' just in order to satisfy the
requirement (whether or not the page data actually needs such padding).

This patch aims to clarify the code by changing the 'hdrsize' argument
to remove that 1 word of padding. This means we need to subtract the
padding from all the existing callers.

Fixes: 02ef04e4

 ("NFS: Account for XDR pad of buf->pages")
Signed-off-by: default avatarTrond Myklebust <trond.myklebust@hammerspace.com>
      9ed5af26
  41. 21 Sep, 2020 8 commits
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