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There is nice kernel helper to escape a given strings by provided rules. Let's
use it instead of custom approach.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
[bfields@redhat.com: fix length calculation]
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
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...move the WARN_ON_ONCE inside the following if block since they use
the same condition.
Signed-off-by: Jeff Layton <jlayton@primarydata.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
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These were useful when I was tracking down a race condition between
svc_xprt_do_enqueue and svc_get_next_xprt.
Signed-off-by: Jeff Layton <jlayton@primarydata.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
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Testing has shown that the pool->sp_lock can be a bottleneck on a busy
server. Every time data is received on a socket, the server must take
that lock in order to dequeue a thread from the sp_threads list.
Address this problem by eliminating the sp_threads list (which contains
threads that are currently idle) and replacing it with a RQ_BUSY flag in
svc_rqst. This allows us to walk the sp_all_threads list under the
rcu_read_lock and find a suitable thread for the xprt by doing a
test_and_set_bit.
Note that we do still have a potential atomicity problem however with
this approach. We don't want svc_xprt_do_enqueue to set the
rqst->rq_xprt pointer unless a test_and_set_bit of RQ_BUSY returned
zero (which indicates that the thread was idle). But, by the time we
check that, the bit could be flipped by a waking thread.
To address this, we acquire a new per-rqst spinlock (rq_lock) and take
that before doing the test_and_set_bit. If that returns false, then we
can set rq_xprt and drop the spinlock. Then, when the thread wakes up,
it must set the bit under the same spinlock and can trust that if it was
already set then the rq_xprt is also properly set.
With this scheme, the case where we have an idle thread no longer needs
to take the highly contended pool->sp_lock at all, and that removes the
bottleneck.
That still leaves one issue: What of the case where we walk the whole
sp_all_threads list and don't find an idle thread? Because the search is
lockess, it's possible for the queueing to race with a thread that is
going to sleep. To address that, we queue the xprt and then search again.
If we find an idle thread at that point, we can't attach the xprt to it
directly since that might race with a different thread waking up and
finding it. All we can do is wake the idle thread back up and let it
attempt to find the now-queued xprt.
Signed-off-by: Jeff Layton <jlayton@primarydata.com>
Tested-by: Chris Worley <chris.worley@primarydata.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
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In a later patch, we'll be removing some spinlocking around the socket
and thread queueing code in order to fix some contention problems. At
that point, the stats counters will no longer be protected by the
sp_lock.
Change the counters to atomic_long_t fields, except for the
"sockets_queued" counter which will still be manipulated under a
spinlock.
Signed-off-by: Jeff Layton <jlayton@primarydata.com>
Tested-by: Chris Worley <chris.worley@primarydata.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
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...also make the manipulation of sp_all_threads list use RCU-friendly
functions.
Signed-off-by: Jeff Layton <jlayton@primarydata.com>
Tested-by: Chris Worley <chris.worley@primarydata.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
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Currently all svc_create callers pass in NULL for the shutdown parm,
which then gets fixed up to be svc_rpcb_cleanup if the service uses
rpcbind.
Simplify this by instead having the the only caller that requires it
(lockd) pass in svc_rpcb_cleanup and get rid of the special casing.
Signed-off-by: Jeff Layton <jlayton@primarydata.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
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The way that svc_wake_up works is a bit inefficient. It walks all of the
available pools for a service and either wakes up a task in each one or
sets the SP_TASK_PENDING flag in each one.
When svc_wake_up is called, there is no need to wake up more than one
thread to do this work. In practice, only lockd currently uses this
function and it's single threaded anyway. Thus, this just boils down to
doing a wake up of a thread in pool 0 or setting a single flag.
Eliminate the for loop in this function and change it to just operate on
pool 0. Also update the comments that sit above it and get rid of some
code that has been commented out for years now.
Signed-off-by: Jeff Layton <jlayton@primarydata.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
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In a later patch, we'll want to be able to handle this flag without
holding the sp_lock. Change this field to an unsigned long flags
field, and declare a new flag in it that can be managed with atomic
bitops.
Signed-off-by: Jeff Layton <jlayton@primarydata.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
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Signed-off-by: Jeff Layton <jlayton@primarydata.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
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Signed-off-by: Jeff Layton <jlayton@primarydata.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
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Signed-off-by: Jeff Layton <jlayton@primarydata.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
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Signed-off-by: Jeff Layton <jlayton@primarydata.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
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In a later patch, we're going to need some atomic bit flags. Since that
field will need to be an unsigned long, we mitigate that space
consumption by migrating some other bitflags to the new field. Start
with the rq_secure flag.
Signed-off-by: Jeff Layton <jlayton@primarydata.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
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Mainly what I need is 860a0d9e511f "sunrpc: add some tracepoints in
svc_rqst handling functions", which subsequent server rpc patches from
jlayton depend on. I'm merging this later tag on the assumption that's
more likely to be a tested and stable point.
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Currently, it leaks when the allocation fails.
Signed-off-by: Jeff Layton <jlayton@primarydata.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
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All it does is indicate whether a xprt has already been deleted from
a list or not, which is unnecessary since we use list_del_init and it's
always set and checked under the sv_lock anyway.
Signed-off-by: Jeff Layton <jlayton@primarydata.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
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Add a new directory heirarchy under the debugfs sunrpc/ directory:
sunrpc/
rpc_xprt/
<xprt id>/
Within that directory, we can put files that give info about the
xprts. We do have the (minor) problem that there is no succinct,
unique identifier for rpc_xprts. So we generate them synthetically
with a static atomic_t counter.
For now, this directory just holds an "info" file, but we may add
other files to it in the future.
Signed-off-by: Jeff Layton <jlayton@primarydata.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
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It's possible to get a dump of the RPC task queue by writing a value to
/proc/sys/sunrpc/rpc_debug. If you write any value to that file, you get
a dump of the RPC client task list into the log buffer. This is a rather
inconvenient interface however, and makes it hard to get immediate info
about the task queue.
Add a new directory hierarchy under debugfs:
sunrpc/
rpc_clnt/
<clientid>/
Within each clientid directory we create a new "tasks" file that will
dump info similar to what shows up in the log buffer, but with a few
small differences -- we avoid printing raw kernel addresses in favor of
symbolic names and the XID is also displayed.
Signed-off-by: Jeff Layton <jlayton@primarydata.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
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git://git.linux-nfs.org/projects/anna/nfs-rdma into linux-next
Pull NFS client RDMA changes for 3.19 from Anna Schumaker:
"NFS: Client side changes for RDMA
These patches various bugfixes and cleanups for using NFS over RDMA, including
better error handling and performance improvements by using pad optimization.
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>"
* tag 'nfs-rdma-for-3.19' of git://git.linux-nfs.org/projects/anna/nfs-rdma:
xprtrdma: Display async errors
xprtrdma: Enable pad optimization
xprtrdma: Re-write rpcrdma_flush_cqs()
xprtrdma: Refactor tasklet scheduling
xprtrdma: unmap all FMRs during transport disconnect
xprtrdma: Cap req_cqinit
xprtrdma: Return an errno from rpcrdma_register_external()
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git://git.linux-nfs.org/projects/anna/nfs-rdma into linux-next
Pull pull additional NFS client changes for 3.19 from Anna Schumaker:
"NFS: Generic client side changes from Chuck
These patches fixes for iostats and SETCLIENTID in addition to cleaning
up the nfs4_init_callback() function.
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>"
* tag 'nfs-cel-for-3.19' of git://git.linux-nfs.org/projects/anna/nfs-rdma:
NFS: Clean up nfs4_init_callback()
NFS: SETCLIENTID XDR buffer sizes are incorrect
SUNRPC: serialize iostats updates
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Occasionally mountstats reports a negative retransmission rate.
Ensure that two RPCs completing concurrently don't confuse the sums
in the transport's op_metrics array.
Since pNFS filelayout can invoke rpc_count_iostats() on another
transport from xprt_release(), we can't rely on simply holding the
transport_lock in xprt_release(). There's nothing for it but hard
serialization. One spin lock per RPC operation should make this as
painless as it can be.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
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An async error upcall is a hard error, and should be reported in
the system log.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
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The Linux NFS/RDMA server used to reject NFSv3 WRITE requests when
pad optimization was enabled. That bug was fixed by commit
e560e3b510d2 ("svcrdma: Add zero padding if the client doesn't send
it").
We can now enable pad optimization on the client, which helps
performance and is supported now by both Linux and Solaris servers.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
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Currently rpcrdma_flush_cqs() attempts to avoid code duplication,
and simply invokes rpcrdma_recvcq_upcall and rpcrdma_sendcq_upcall.
1. rpcrdma_flush_cqs() can run concurrently with provider upcalls.
Both flush_cqs() and the upcalls were invoking ib_poll_cq() in
different threads using the same wc buffers (ep->rep_recv_wcs
and ep->rep_send_wcs), added by commit 1c00dd077654 ("xprtrmda:
Reduce calls to ib_poll_cq() in completion handlers").
During transport disconnect processing, this sometimes resulted
in the same reply getting added to the rpcrdma_tasklets_g list
more than once, which corrupted the list.
2. The upcall functions drain only a limited number of CQEs,
thanks to the poll budget added by commit 8301a2c047cc
("xprtrdma: Limit work done by completion handler").
Fixes: a7bc211ac926 ("xprtrdma: On disconnect, don't ignore ... ")
BugLink: https://bugzilla.linux-nfs.org/show_bug.cgi?id=276
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
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Restore the separate function that schedules the reply handling
tasklet. I need to call it from two different paths.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
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When using RPCRDMA_MTHCAFMR memory registration, after a few
transport disconnect / reconnect cycles, ib_map_phys_fmr() starts to
return EINVAL because the provider has exhausted its map pool.
Make sure that all FMRs are unmapped during transport disconnect,
and that ->send_request remarshals them during an RPC retransmit.
This resets the transport's MRs to ensure that none are leaked
during a disconnect.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
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Recent work made FRMR registration and invalidation completions
unsignaled. This greatly reduces the adapter interrupt rate.
Every so often, however, a posted send Work Request is allowed to
signal. Otherwise, the provider's Work Queue will wrap and the
workload will hang.
The number of Work Requests that are allowed to remain unsignaled is
determined by the value of req_cqinit. Currently, this is set to the
size of the send Work Queue divided by two, minus 1.
For FRMR, the send Work Queue is the maximum number of concurrent
RPCs (currently 32) times the maximum number of Work Requests an
RPC might use (currently 7, though some adapters may need more).
For mlx4, this is 224 entries. This leaves completion signaling
disabled for 111 send Work Requests.
Some providers hold back dispatching Work Requests until a CQE is
generated. If completions are disabled, then no CQEs are generated
for quite some time, and that can stall the Work Queue.
I've seen this occur running xfstests generic/113 over NFSv4, where
eventually, posting a FAST_REG_MR Work Request fails with -ENOMEM
because the Work Queue has overflowed. The connection is dropped
and re-established.
Cap the rep_cqinit setting so completions are not left turned off
for too long.
BugLink: https://bugzilla.linux-nfs.org/show_bug.cgi?id=269
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
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The RPC/RDMA send_request method and the chunk registration code
expects an errno from the registration function. This allows
the upper layers to distinguish between a recoverable failure
(for example, temporary memory exhaustion) and a hard failure
(for example, a bug in the registration logic).
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
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It's always set to the same value as CONFIG_TRACEPOINTS, so we can just
use that instead.
Signed-off-by: Jeff Layton <jlayton@primarydata.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
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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>
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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>
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...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>
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...just around svc_send, svc_recv and svc_process for now.
Signed-off-by: Jeff Layton <jlayton@primarydata.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
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In addition to nfsd bugfixes, there are some fixes in -rc5 for client
bugs that can interfere with my testing.
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Both xprt_lookup_rqst() and xprt_complete_rqst() require that you
take the transport lock in order to avoid races with xprt_transmit().
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Cc: stable@vger.kernel.org
Reviewed-by: Jeff Layton <jlayton@primarydata.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
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Bruce reported that he was seeing the following BUG pop:
BUG: sleeping function called from invalid context at mm/slab.c:2846
in_atomic(): 0, irqs_disabled(): 0, pid: 4539, name: mount.nfs
2 locks held by mount.nfs/4539:
#0: (nfs_clid_init_mutex){+.+.+.}, at: [<ffffffffa01c0a9a>] nfs4_discover_server_trunking+0x4a/0x2f0 [nfsv4]
#1: (rcu_read_lock){......}, at: [<ffffffffa00e3185>] gss_stringify_acceptor+0x5/0xb0 [auth_rpcgss]
Preemption disabled at:[<ffffffff81a4f082>] printk+0x4d/0x4f
CPU: 3 PID: 4539 Comm: mount.nfs Not tainted 3.18.0-rc1-00013-g5b095e9 #3393
Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
ffff880021499390 ffff8800381476a8 ffffffff81a534cf 0000000000000001
0000000000000000 ffff8800381476c8 ffffffff81097854 00000000000000d0
0000000000000018 ffff880038147718 ffffffff8118e4f3 0000000020479f00
Call Trace:
[<ffffffff81a534cf>] dump_stack+0x4f/0x7c
[<ffffffff81097854>] __might_sleep+0x114/0x180
[<ffffffff8118e4f3>] __kmalloc+0x1a3/0x280
[<ffffffffa00e31d8>] gss_stringify_acceptor+0x58/0xb0 [auth_rpcgss]
[<ffffffffa00e3185>] ? gss_stringify_acceptor+0x5/0xb0 [auth_rpcgss]
[<ffffffffa006b438>] rpcauth_stringify_acceptor+0x18/0x30 [sunrpc]
[<ffffffffa01b0469>] nfs4_proc_setclientid+0x199/0x380 [nfsv4]
[<ffffffffa01b04d0>] ? nfs4_proc_setclientid+0x200/0x380 [nfsv4]
[<ffffffffa01bdf1a>] nfs40_discover_server_trunking+0xda/0x150 [nfsv4]
[<ffffffffa01bde45>] ? nfs40_discover_server_trunking+0x5/0x150 [nfsv4]
[<ffffffffa01c0acf>] nfs4_discover_server_trunking+0x7f/0x2f0 [nfsv4]
[<ffffffffa01c8e24>] nfs4_init_client+0x104/0x2f0 [nfsv4]
[<ffffffffa01539b4>] nfs_get_client+0x314/0x3f0 [nfs]
[<ffffffffa0153780>] ? nfs_get_client+0xe0/0x3f0 [nfs]
[<ffffffffa01c83aa>] nfs4_set_client+0x8a/0x110 [nfsv4]
[<ffffffffa0069708>] ? __rpc_init_priority_wait_queue+0xa8/0xf0 [sunrpc]
[<ffffffffa01c9b2f>] nfs4_create_server+0x12f/0x390 [nfsv4]
[<ffffffffa01c1472>] nfs4_remote_mount+0x32/0x60 [nfsv4]
[<ffffffff81196489>] mount_fs+0x39/0x1b0
[<ffffffff81166145>] ? __alloc_percpu+0x15/0x20
[<ffffffff811b276b>] vfs_kern_mount+0x6b/0x150
[<ffffffffa01c1396>] nfs_do_root_mount+0x86/0xc0 [nfsv4]
[<ffffffffa01c1784>] nfs4_try_mount+0x44/0xc0 [nfsv4]
[<ffffffffa01549b7>] ? get_nfs_version+0x27/0x90 [nfs]
[<ffffffffa0161a2d>] nfs_fs_mount+0x47d/0xd60 [nfs]
[<ffffffff81a59c5e>] ? mutex_unlock+0xe/0x10
[<ffffffffa01606a0>] ? nfs_remount+0x430/0x430 [nfs]
[<ffffffffa01609c0>] ? nfs_clone_super+0x140/0x140 [nfs]
[<ffffffff81196489>] mount_fs+0x39/0x1b0
[<ffffffff81166145>] ? __alloc_percpu+0x15/0x20
[<ffffffff811b276b>] vfs_kern_mount+0x6b/0x150
[<ffffffff811b5830>] do_mount+0x210/0xbe0
[<ffffffff811b54ca>] ? copy_mount_options+0x3a/0x160
[<ffffffff811b651f>] SyS_mount+0x6f/0xb0
[<ffffffff81a5c852>] system_call_fastpath+0x12/0x17
Sleeping under the rcu_read_lock is bad. This patch fixes it by dropping
the rcu_read_lock before doing the allocation and then reacquiring it
and redoing the dereference before doing the copy. If we find that the
string has somehow grown in the meantime, we'll reallocate and try again.
Cc: <stable@vger.kernel.org> # v3.17+
Reported-by: "J. Bruce Fields" <bfields@fieldses.org>
Signed-off-by: Jeff Layton <jlayton@primarydata.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
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The m->pool_to[] array has "maxpools" number of elements. It's
allocated in svc_pool_map_alloc_arrays() which we called earlier in the
function. This test should be >= instead of >.
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
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Reported-by: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
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Thanks to Andrea Arcangeli for pointing out these checks are
obviously unnecessary given the preceding calculations.
Reported-by: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
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Pull nfsd updates from Bruce Fields:
"Highlights:
- support the NFSv4.2 SEEK operation (allowing clients to support
SEEK_HOLE/SEEK_DATA), thanks to Anna.
- end the grace period early in a number of cases, mitigating a
long-standing annoyance, thanks to Jeff
- improve SMP scalability, thanks to Trond"
* 'for-3.18' of git://linux-nfs.org/~bfields/linux: (55 commits)
nfsd: eliminate "to_delegation" define
NFSD: Implement SEEK
NFSD: Add generic v4.2 infrastructure
svcrdma: advertise the correct max payload
nfsd: introduce nfsd4_callback_ops
nfsd: split nfsd4_callback initialization and use
nfsd: introduce a generic nfsd4_cb
nfsd: remove nfsd4_callback.cb_op
nfsd: do not clear rpc_resp in nfsd4_cb_done_sequence
nfsd: fix nfsd4_cb_recall_done error handling
nfsd4: clarify how grace period ends
nfsd4: stop grace_time update at end of grace period
nfsd: skip subsequent UMH "create" operations after the first one for v4.0 clients
nfsd: set and test NFSD4_CLIENT_STABLE bit to reduce nfsdcltrack upcalls
nfsd: serialize nfsdcltrack upcalls for a particular client
nfsd: pass extra info in env vars to upcalls to allow for early grace period end
nfsd: add a v4_end_grace file to /proc/fs/nfsd
lockd: add a /proc/fs/lockd/nlm_end_grace file
nfsd: reject reclaim request when client has already sent RECLAIM_COMPLETE
nfsd: remove redundant boot_time parm from grace_done client tracking op
...
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* bugfixes:
NFSv4.1: Fix an NFSv4.1 state renewal regression
NFSv4: fix open/lock state recovery error handling
NFSv4: Fix lock recovery when CREATE_SESSION/SETCLIENTID_CONFIRM fails
NFS: Fabricate fscache server index key correctly
SUNRPC: Add missing support for RPC_CLNT_CREATE_NO_RETRANS_TIMEOUT
nfs: fix duplicate proc entries
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Svcrdma currently advertises 1MB, which is too large. The correct value
is the minimum of RPCSVC_MAXPAYLOAD and the max scatter-gather allowed
in an NFSRDMA IO chunk * the host page size. This bug is usually benign
because the Linux X64 NFSRDMA client correctly limits the payload size to
the correct value (64*4096 = 256KB). But if the Linux client is PPC64
with a 64KB page size, then the client will indeed use a payload size
that will overflow the server.
Signed-off-by: Steve Wise <swise@opengridcomputing.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
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The flag RPC_CLNT_CREATE_NO_RETRANS_TIMEOUT was intended introduced in
order to allow NFSv4 clients to disable resend timeouts. Since those
cause the RPC layer to break the connection, they mess up the duplicate
reply caches that remain indexed on the port number in NFSv4..
This patch includes the code that was missing in the original to
set the appropriate flag in struct rpc_clnt, when the caller of
rpc_create() sets RPC_CLNT_CREATE_NO_RETRANS_TIMEOUT.
Fixes: 8a19a0b6cb2e (SUNRPC: Add RPC task and client level options to...)
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
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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>
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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>
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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>
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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>
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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>
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xprt_lookup_rqst() and bc_send_request() display a byte-swapped XID,
but receive_cb_reply() does not.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
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