xs_tcp_close() is now just a call to xs_tcp_shutdown(), so remove it,
and replace the entry in xs_tcp_ops.
Suggested-by: Anna Schumaker <anna.schumaker@netapp.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Now that the linger code is gone, the xs_tcp_fin_timeout variable has
no real function. Keep it for now, since it is part of the /proc
interface, but only define it if that /proc interface is enabled.
Suggested-by: Anna Schumaker <Anna.Schumaker@netapp.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
If the connection reset is due to an active call on our side, then
the state change is sometimes not reported. Catch those instances
using xs_error_report() instead.
Also remove the xs_tcp_shutdown() call in xs_tcp_send_request() as
the change in behaviour makes it redundant.
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Use of socket shutdown() means that we monitor the shutdown process
through the xs_tcp_state_change() callback, so it is preferable to
a full close in all cases unless we're destroying the transport.
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
The previous behaviour left the connection half-open in order to try
to scrape the last replies from the socket. Now that we have more reliable
reconnection, change the behaviour to close down the socket faster.
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Now that we no longer use the partial shutdown code when closing the
socket, we no longer need to worry about the TCP linger2 state.
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Instead we rely on SO_REUSEPORT to provide the reconnection semantics
that we need for NFSv2/v3.
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
It is not safe to call xs_reset_transport() from inside xs_udp_setup_socket()
or xs_tcp_setup_socket(), since they do not own the correct locks. Instead,
do it in xs_connect().
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
The socket lock is currently held by the task that is requesting the
connection be established. While that is efficient in the case where
the connection happens quickly, it is racy in the case where it doesn't.
What we really want is for the connect helper to be able to block access
to the socket while it is being set up.
This patch does so by arranging to transfer the socket lock from the
task that is requesting the connect attempt, and then releasing that
lock once everything is done.
This scheme also gives us automatic protection against collisions with
the RPC close code, so we can kill the cancel_delayed_work_sync()
call in xs_close().
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Now that we can reuse bound ports after a close, we never really want to
clear the transport's source port after it has been set. Doing so really
messes up the NFSv3 DRC on the server.
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Now that we're setting SO_REUSEPORT, we still need to handle the
case where a connect() is attempted, but the old socket is still
lingering.
Essentially, all we want to do here is handle the error by waiting
a few seconds and then retrying.
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
When using TCP, we need the ability to reuse port numbers after
a disconnection, so that the NFSv3 server knows that we're the same
client. Currently we use a hack to work around the TCP socket's
TIME_WAIT: we send an RST instead of closing, which doesn't
always work...
The SO_REUSEPORT option added in Linux 3.9 allows us to bind multiple
TCP connections to the same source address+port combination, and thus
to use ordinary TCP close() instead of the current hack.
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
It's always set to whatever CONFIG_SUNRPC_DEBUG is, so just use that.
Signed-off-by: Jeff Layton <jlayton@primarydata.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Add tracepoints inside the main loop on xs_tcp_data_recv that allow
us to keep an eye on what's happening during each phase of it.
Signed-off-by: Jeff Layton <jlayton@primarydata.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
...so we can keep track of when calls are sent and replies received.
Signed-off-by: Jeff Layton <jlayton@primarydata.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Now that nfs_release_page() doesn't block indefinitely, other deadlock
avoidance mechanisms aren't needed.
- it doesn't hurt for kswapd to block occasionally. If it doesn't
want to block it would clear __GFP_WAIT. The current_is_kswapd()
was only added to avoid deadlocks and we have a new approach for
that.
- memory allocation in the SUNRPC layer can very rarely try to
->releasepage() a page it is trying to handle. The deadlock
is removed as nfs_release_page() doesn't block indefinitely.
So we don't need to set PF_FSTRANS for sunrpc network operations any
more.
Signed-off-by: NeilBrown <neilb@suse.de>
Acked-by: Jeff Layton <jlayton@primarydata.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
If an iptables drop rule is added for an nfs server, the client can end up in
a softlockup. Because of the way that xs_sendpages() is structured, the -EPERM
is ignored since the prior bits of the packet may have been successfully queued
and thus xs_sendpages() returns a non-zero value. Then, xs_udp_send_request()
thinks that because some bits were queued it should return -EAGAIN. We then try
the request again and again, resulting in cpu spinning. Reproducer:
1) open a file on the nfs server '/nfs/foo' (mounted using udp)
2) iptables -A OUTPUT -d <nfs server ip> -j DROP
3) write to /nfs/foo
4) close /nfs/foo
5) iptables -D OUTPUT -d <nfs server ip> -j DROP
The softlockup occurs in step 4 above.
The previous patch, allows xs_sendpages() to return both a sent count and
any error values that may have occurred. Thus, if we get an -EPERM, return
that to the higher level code.
With this patch in place we can successfully abort the above sequence and
avoid the softlockup.
I also tried the above test case on an nfs mount on tcp and although the system
does not softlockup, I still ended up with the 'hung_task' firing after 120
seconds, due to the i/o being stuck. The tcp case appears a bit harder to fix,
since -EPERM appears to get ignored much lower down in the stack and does not
propogate up to xs_sendpages(). This case is not quite as insidious as the
softlockup and it is not addressed here.
Reported-by: Yigong Lou <ylou@akamai.com>
Signed-off-by: Jason Baron <jbaron@akamai.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
If an error is returned after the first bits of a packet have already been
successfully queued, xs_sendpages() will return a positive 'int' value
indicating success. Callers seem to treat this as -EAGAIN.
However, there are cases where its not a question of waiting for the write
queue to drain. For example, when there is an iptables rule dropping packets
to the destination, the lower level code can return -EPERM only after parts
of the packet have been successfully queued. In this case, we can end up
continuously retrying resulting in a kernel softlockup.
This patch is intended to make no changes in behavior but is in preparation for
subsequent patches that can make decisions based on both on the number of bytes
sent by xs_sendpages() and any errors that may have be returned.
Signed-off-by: Jason Baron <jbaron@akamai.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
When aborting a connection to preserve source ports, don't wake the task in
xs_error_report. This allows tasks with RPC_TASK_SOFTCONN to succeed if the
connection needs to be re-established since it preserves the task's status
instead of setting it to the status of the aborting kernel_connect().
This may also avoid a potential conflict on the socket's lock.
Signed-off-by: Benjamin Coddington <bcodding@redhat.com>
Cc: stable@vger.kernel.org # 3.14+
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
When attempting to establish a local ephemeral endpoint for a TCP or UDP
socket, do not explicitly call bind, instead let it happen implicilty when the
socket is first used.
The main motivating factor for this change is when TCP runs out of unique
ephemeral ports (i.e. cannot find any ephemeral ports which are not a part of
*any* TCP connection). In this situation if you explicitly call bind, then the
call will fail with EADDRINUSE. However, if you allow the allocation of an
ephemeral port to happen implicitly as part of connect (or other functions),
then ephemeral ports can be reused, so long as the combination of (local_ip,
local_port, remote_ip, remote_port) is unique for TCP sockets on the system.
This doesn't matter for UDP sockets, but it seemed easiest to treat TCP and UDP
sockets the same.
This can allow mount.nfs(8) to continue to function successfully, even in the
face of misbehaving applications which are creating a large number of TCP
connections.
Signed-off-by: Chris Perl <chris.perl@gmail.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Currently, an ENOBUFS error will result in a fatal error for the RPC
call. Normally, we will just want to wait and then retry.
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Pull networking updates from David Miller:
1) Seccomp BPF filters can now be JIT'd, from Alexei Starovoitov.
2) Multiqueue support in xen-netback and xen-netfront, from Andrew J
Benniston.
3) Allow tweaking of aggregation settings in cdc_ncm driver, from Bjørn
Mork.
4) BPF now has a "random" opcode, from Chema Gonzalez.
5) Add more BPF documentation and improve test framework, from Daniel
Borkmann.
6) Support TCP fastopen over ipv6, from Daniel Lee.
7) Add software TSO helper functions and use them to support software
TSO in mvneta and mv643xx_eth drivers. From Ezequiel Garcia.
8) Support software TSO in fec driver too, from Nimrod Andy.
9) Add Broadcom SYSTEMPORT driver, from Florian Fainelli.
10) Handle broadcasts more gracefully over macvlan when there are large
numbers of interfaces configured, from Herbert Xu.
11) Allow more control over fwmark used for non-socket based responses,
from Lorenzo Colitti.
12) Do TCP congestion window limiting based upon measurements, from Neal
Cardwell.
13) Support busy polling in SCTP, from Neal Horman.
14) Allow RSS key to be configured via ethtool, from Venkata Duvvuru.
15) Bridge promisc mode handling improvements from Vlad Yasevich.
16) Don't use inetpeer entries to implement ID generation any more, it
performs poorly, from Eric Dumazet.
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next: (1522 commits)
rtnetlink: fix userspace API breakage for iproute2 < v3.9.0
tcp: fixing TLP's FIN recovery
net: fec: Add software TSO support
net: fec: Add Scatter/gather support
net: fec: Increase buffer descriptor entry number
net: fec: Factorize feature setting
net: fec: Enable IP header hardware checksum
net: fec: Factorize the .xmit transmit function
bridge: fix compile error when compiling without IPv6 support
bridge: fix smatch warning / potential null pointer dereference
via-rhine: fix full-duplex with autoneg disable
bnx2x: Enlarge the dorq threshold for VFs
bnx2x: Check for UNDI in uncommon branch
bnx2x: Fix 1G-baseT link
bnx2x: Fix link for KR with swapped polarity lane
sctp: Fix sk_ack_backlog wrap-around problem
net/core: Add VF link state control policy
net/fsl: xgmac_mdio is dependent on OF_MDIO
net/fsl: Make xgmac_mdio read error message useful
net_sched: drr: warn when qdisc is not work conserving
...
Setting sk_no_check to UDP_CSUM_NORCV seems to have no effect.
Signed-off-by: Tom Herbert <therbert@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Pull yet more networking updates from David Miller:
1) Various fixes to the new Redpine Signals wireless driver, from
Fariya Fatima.
2) L2TP PPP connect code takes PMTU from the wrong socket, fix from
Dmitry Petukhov.
3) UFO and TSO packets differ in whether they include the protocol
header in gso_size, account for that in skb_gso_transport_seglen().
From Florian Westphal.
4) If VLAN untagging fails, we double free the SKB in the bridging
output path. From Toshiaki Makita.
5) Several call sites of sk->sk_data_ready() were referencing an SKB
just added to the socket receive queue in order to calculate the
second argument via skb->len. This is dangerous because the moment
the skb is added to the receive queue it can be consumed in another
context and freed up.
It turns out also that none of the sk->sk_data_ready()
implementations even care about this second argument.
So just kill it off and thus fix all these use-after-free bugs as a
side effect.
6) Fix inverted test in tcp_v6_send_response(), from Lorenzo Colitti.
7) pktgen needs to do locking properly for LLTX devices, from Daniel
Borkmann.
8) xen-netfront driver initializes TX array entries in RX loop :-) From
Vincenzo Maffione.
9) After refactoring, some tunnel drivers allow a tunnel to be
configured on top itself. Fix from Nicolas Dichtel.
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (46 commits)
vti: don't allow to add the same tunnel twice
gre: don't allow to add the same tunnel twice
drivers: net: xen-netfront: fix array initialization bug
pktgen: be friendly to LLTX devices
r8152: check RTL8152_UNPLUG
net: sun4i-emac: add promiscuous support
net/apne: replace IS_ERR and PTR_ERR with PTR_ERR_OR_ZERO
net: ipv6: Fix oif in TCP SYN+ACK route lookup.
drivers: net: cpsw: enable interrupts after napi enable and clearing previous interrupts
drivers: net: cpsw: discard all packets received when interface is down
net: Fix use after free by removing length arg from sk_data_ready callbacks.
Drivers: net: hyperv: Address UDP checksum issues
Drivers: net: hyperv: Negotiate suitable ndis version for offload support
Drivers: net: hyperv: Allocate memory for all possible per-pecket information
bridge: Fix double free and memory leak around br_allowed_ingress
bonding: Remove debug_fs files when module init fails
i40evf: program RSS LUT correctly
i40evf: remove open-coded skb_cow_head
ixgb: remove open-coded skb_cow_head
igbvf: remove open-coded skb_cow_head
...
Several spots in the kernel perform a sequence like:
skb_queue_tail(&sk->s_receive_queue, skb);
sk->sk_data_ready(sk, skb->len);
But at the moment we place the SKB onto the socket receive queue it
can be consumed and freed up. So this skb->len access is potentially
to freed up memory.
Furthermore, the skb->len can be modified by the consumer so it is
possible that the value isn't accurate.
And finally, no actual implementation of this callback actually uses
the length argument. And since nobody actually cared about it's
value, lots of call sites pass arbitrary values in such as '0' and
even '1'.
So just remove the length argument from the callback, that way there
is no confusion whatsoever and all of these use-after-free cases get
fixed as a side effect.
Based upon a patch by Eric Dumazet and his suggestion to audit this
issue tree-wide.
Signed-off-by: David S. Miller <davem@davemloft.net>
Pull nfsd updates from Bruce Fields:
"Highlights:
- server-side nfs/rdma fixes from Jeff Layton and Tom Tucker
- xdr fixes (a larger xdr rewrite has been posted but I decided it
would be better to queue it up for 3.16).
- miscellaneous fixes and cleanup from all over (thanks especially to
Kinglong Mee)"
* 'for-3.15' of git://linux-nfs.org/~bfields/linux: (36 commits)
nfsd4: don't create unnecessary mask acl
nfsd: revert v2 half of "nfsd: don't return high mode bits"
nfsd4: fix memory leak in nfsd4_encode_fattr()
nfsd: check passed socket's net matches NFSd superblock's one
SUNRPC: Clear xpt_bc_xprt if xs_setup_bc_tcp failed
NFSD/SUNRPC: Check rpc_xprt out of xs_setup_bc_tcp
SUNRPC: New helper for creating client with rpc_xprt
NFSD: Free backchannel xprt in bc_destroy
NFSD: Clear wcc data between compound ops
nfsd: Don't return NFS4ERR_STALE_STATEID for NFSv4.1+
nfsd4: fix nfs4err_resource in 4.1 case
nfsd4: fix setclientid encode size
nfsd4: remove redundant check from nfsd4_check_resp_size
nfsd4: use more generous NFS4_ACL_MAX
nfsd4: minor nfsd4_replay_cache_entry cleanup
nfsd4: nfsd4_replay_cache_entry should be static
nfsd4: update comments with obsolete function name
rpc: Allow xdr_buf_subsegment to operate in-place
NFSD: Using free_conn free connection
SUNRPC: fix memory leak of peer addresses in XPRT
...
Don't move the assign of args->bc_xprt->xpt_bc_xprt out of xs_setup_bc_tcp,
because rpc_ping (which is in rpc_create) will using it.
Signed-off-by: Kinglong Mee <kinglongmee@gmail.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Besides checking rpc_xprt out of xs_setup_bc_tcp,
increase it's reference (it's important).
Signed-off-by: Kinglong Mee <kinglongmee@gmail.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Backchannel xprt isn't freed right now.
Free it in bc_destroy, and put the reference of THIS_MODULE.
Signed-off-by: Kinglong Mee <kinglongmee@gmail.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Creating xprt failed after xs_format_peer_addresses,
sunrpc must free those memory of peer addresses in xprt.
Signed-off-by: Kinglong Mee <kinglongmee@gmail.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Since TCP is a stream protocol, our callback read code needs to take into
account the fact that RPC callbacks are not always confined to a single
TCP segment.
This patch adds support for multiple TCP segments by ensuring that we
only remove the rpc_rqst structure from the 'free backchannel requests'
list once the data has been completely received. We rely on the fact
that TCP data is ordered for the duration of the connection.
Reported-by: shaobingqing <shaobingqing@bwstor.com.cn>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
When a send failure occurs due to the socket being out of buffer space,
we call xs_nospace() in order to have the RPC task wait until the
socket has drained enough to make it worth while trying again.
The current patch fixes a race in which the socket is drained before
we get round to setting up the machinery in xs_nospace(), and which
is reported to cause hangs.
Link: http://lkml.kernel.org/r/20140210170315.33dfc621@notabene.brown
Fixes: a9a6b52ee1 (SUNRPC: Don't start the retransmission timer...)
Reported-by: Neil Brown <neilb@suse.com>
Cc: stable@vger.kernel.org
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Pull nfsd updates from Bruce Fields:
- Handle some loose ends from the vfs read delegation support.
(For example nfsd can stop breaking leases on its own in a
fewer places where it can now depend on the vfs to.)
- Make life a little easier for NFSv4-only configurations
(thanks to Kinglong Mee).
- Fix some gss-proxy problems (thanks Jeff Layton).
- miscellaneous bug fixes and cleanup
* 'for-3.14' of git://linux-nfs.org/~bfields/linux: (38 commits)
nfsd: consider CLAIM_FH when handing out delegation
nfsd4: fix delegation-unlink/rename race
nfsd4: delay setting current_fh in open
nfsd4: minor nfs4_setlease cleanup
gss_krb5: use lcm from kernel lib
nfsd4: decrease nfsd4_encode_fattr stack usage
nfsd: fix encode_entryplus_baggage stack usage
nfsd4: simplify xdr encoding of nfsv4 names
nfsd4: encode_rdattr_error cleanup
nfsd4: nfsd4_encode_fattr cleanup
minor svcauth_gss.c cleanup
nfsd4: better VERIFY comment
nfsd4: break only delegations when appropriate
NFSD: Fix a memory leak in nfsd4_create_session
sunrpc: get rid of use_gssp_lock
sunrpc: fix potential race between setting use_gss_proxy and the upcall rpc_clnt
sunrpc: don't wait for write before allowing reads from use-gss-proxy file
nfsd: get rid of unused function definition
Define op_iattr for nfsd4_open instead using macro
NFSD: fix compile warning without CONFIG_NFSD_V3
...
Highlights include:
- Stable fix for an infinite loop in RPC state machine
- Stable fix for a use after free situation in the NFSv4 trunking discovery
- Stable fix for error handling in the NFSv4 trunking discovery
- Stable fix for the page write update code
- Stable fix for the NFSv4.1 mount time security negotiation
- Stable fix for the NFSv4 open code.
- O_DIRECT locking fixes
- fix an Oops in the pnfs file commit code
- RPC layer needs finer grained handling of connection errors
- More RPC GSS upcall fixes
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Merge tag 'nfs-for-3.14-1' of git://git.linux-nfs.org/projects/trondmy/linux-nfs
Pull NFS client updates from Trond Myklebust:
"Highlights include:
- stable fix for an infinite loop in RPC state machine
- stable fix for a use after free situation in the NFSv4 trunking discovery
- stable fix for error handling in the NFSv4 trunking discovery
- stable fix for the page write update code
- stable fix for the NFSv4.1 mount time security negotiation
- stable fix for the NFSv4 open code.
- O_DIRECT locking fixes
- fix an Oops in the pnfs file commit code
- RPC layer needs finer grained handling of connection errors
- more RPC GSS upcall fixes"
* tag 'nfs-for-3.14-1' of git://git.linux-nfs.org/projects/trondmy/linux-nfs: (30 commits)
pnfs: Proper delay for NFS4ERR_RECALLCONFLICT in layout_get_done
pnfs: fix BUG in filelayout_recover_commit_reqs
nfs4: fix discover_server_trunking use after free
NFSv4.1: Handle errors correctly in nfs41_walk_client_list
nfs: always make sure page is up-to-date before extending a write to cover the entire page
nfs: page cache invalidation for dio
nfs: take i_mutex during direct I/O reads
nfs: merge nfs_direct_write into nfs_file_direct_write
nfs: merge nfs_direct_read into nfs_file_direct_read
nfs: increment i_dio_count for reads, too
nfs: defer inode_dio_done call until size update is done
nfs: fix size updates for aio writes
nfs4.1: properly handle ENOTSUP in SECINFO_NO_NAME
NFSv4.1: Fix a race in nfs4_write_inode
NFSv4.1: Don't trust attributes if a pNFS LAYOUTCOMMIT is outstanding
point to the right include file in a comment (left over from a9004abc3)
NFS: dprintk() should not print negative fileids and inode numbers
nfs: fix dead code of ipv6_addr_scope
sunrpc: Fix infinite loop in RPC state machine
SUNRPC: Add tracepoint for socket errors
...
This patch removes the net_random and net_srandom macros and replaces
them with direct calls to the prandom ones. As new commits only seem to
use prandom_u32 there is no use to keep them around.
This change makes it easier to grep for users of prandom_u32.
Signed-off-by: Aruna-Hewapathirane <aruna.hewapathirane@gmail.com>
Suggested-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Acked-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
The following scenario can cause silent data corruption when doing
NFS writes. It has mainly been observed when doing database writes
using O_DIRECT.
1) The RPC client uses sendpage() to do zero-copy of the page data.
2) Due to networking issues, the reply from the server is delayed,
and so the RPC client times out.
3) The client issues a second sendpage of the page data as part of
an RPC call retransmission.
4) The reply to the first transmission arrives from the server
_before_ the client hardware has emptied the TCP socket send
buffer.
5) After processing the reply, the RPC state machine rules that
the call to be done, and triggers the completion callbacks.
6) The application notices the RPC call is done, and reuses the
pages to store something else (e.g. a new write).
7) The client NIC drains the TCP socket send buffer. Since the
page data has now changed, it reads a corrupted version of the
initial RPC call, and puts it on the wire.
This patch fixes the problem in the following manner:
The ordering guarantees of TCP ensure that when the server sends a
reply, then we know that the _first_ transmission has completed. Using
zero-copy in that situation is therefore safe.
If a time out occurs, we then send the retransmission using sendmsg()
(i.e. no zero-copy), We then know that the socket contains a full copy of
the data, and so it will retransmit a faithful reproduction even if the
RPC call completes, and the application reuses the O_DIRECT buffer in
the meantime.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Cc: stable@vger.kernel.org
We have one report of a crash in xs_tcp_setup_socket.
The call path to the crash is:
xs_tcp_setup_socket -> inet_stream_connect -> lock_sock_nested.
The 'sock' passed to that last function is NULL.
The only way I can see this happening is a concurrent call to
xs_close:
xs_close -> xs_reset_transport -> sock_release -> inet_release
inet_release sets:
sock->sk = NULL;
inet_stream_connect calls
lock_sock(sock->sk);
which gets NULL.
All calls to xs_close are protected by XPRT_LOCKED as are most
activations of the workqueue which runs xs_tcp_setup_socket.
The exception is xs_tcp_schedule_linger_timeout.
So presumably the timeout queued by the later fires exactly when some
other code runs xs_close().
To protect against this we can move the cancel_delayed_work_sync()
call from xs_destory() to xs_close().
As xs_close is never called from the worker scheduled on
->connect_worker, this can never deadlock.
Signed-off-by: NeilBrown <neilb@suse.de>
[Trond: Make it safe to call cancel_delayed_work_sync() on AF_LOCAL sockets]
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
For NFSv4 we want to avoid retransmitting RPC calls unless the TCP
connection breaks. However we still want to detect TCP connection
breakage as soon as possible. Do this by setting the keepalive option
with the idle timeout and count set to the 'timeo' and 'retrans' mount
options.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Trond Myklebust