Pull NFS client bugfixes from Trond Myklebust:
"Highlights include:
Bugfix:
- Fix build issues on architectures that don't provide 64-bit cmpxchg
Cleanups:
- Fix a spelling mistake"
* tag 'nfs-for-4.20-2' of git://git.linux-nfs.org/projects/trondmy/linux-nfs:
NFS: fix spelling mistake, EACCESS -> EACCES
SUNRPC: Use atomic(64)_t for seq_send(64)
The seq_send & seq_send64 fields in struct krb5_ctx are used as
atomically incrementing counters. This is implemented using cmpxchg() &
cmpxchg64() to implement what amount to custom versions of
atomic_fetch_inc() & atomic64_fetch_inc().
Besides the duplication, using cmpxchg64() has another major drawback in
that some 32 bit architectures don't provide it. As such commit
571ed1fd23 ("SUNRPC: Replace krb5_seq_lock with a lockless scheme")
resulted in build failures for some architectures.
Change seq_send to be an atomic_t and seq_send64 to be an atomic64_t,
then use atomic(64)_* functions to manipulate the values. The atomic64_t
type & associated functions are provided even on architectures which
lack real 64 bit atomic memory access via CONFIG_GENERIC_ATOMIC64 which
uses spinlocks to serialize access. This fixes the build failures for
architectures lacking cmpxchg64().
A potential alternative that was raised would be to provide cmpxchg64()
on the 32 bit architectures that currently lack it, using spinlocks.
However this would provide a version of cmpxchg64() with semantics a
little different to the implementations on architectures with real 64
bit atomics - the spinlock-based implementation would only work if all
access to the memory used with cmpxchg64() is *always* performed using
cmpxchg64(). That is not currently a requirement for users of
cmpxchg64(), and making it one seems questionable. As such avoiding
cmpxchg64() outside of architecture-specific code seems best,
particularly in cases where atomic64_t seems like a better fit anyway.
The CONFIG_GENERIC_ATOMIC64 implementation of atomic64_* functions will
use spinlocks & so faces the same issue, but with the key difference
that the memory backing an atomic64_t ought to always be accessed via
the atomic64_* functions anyway making the issue moot.
Signed-off-by: Paul Burton <paul.burton@mips.com>
Fixes: 571ed1fd23 ("SUNRPC: Replace krb5_seq_lock with a lockless scheme")
Cc: Trond Myklebust <trond.myklebust@hammerspace.com>
Cc: Anna Schumaker <anna.schumaker@netapp.com>
Cc: J. Bruce Fields <bfields@fieldses.org>
Cc: Jeff Layton <jlayton@kernel.org>
Cc: David S. Miller <davem@davemloft.net>
Cc: linux-nfs@vger.kernel.org
Cc: netdev@vger.kernel.org
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Pull nfsd updates from Bruce Fields:
"Olga added support for the NFSv4.2 asynchronous copy protocol. We
already supported COPY, by copying a limited amount of data and then
returning a short result, letting the client resend. The asynchronous
protocol should offer better performance at the expense of some
complexity.
The other highlight is Trond's work to convert the duplicate reply
cache to a red-black tree, and to move it and some other server caches
to RCU. (Previously these have meant taking global spinlocks on every
RPC)
Otherwise, some RDMA work and miscellaneous bugfixes"
* tag 'nfsd-4.20' of git://linux-nfs.org/~bfields/linux: (30 commits)
lockd: fix access beyond unterminated strings in prints
nfsd: Fix an Oops in free_session()
nfsd: correctly decrement odstate refcount in error path
svcrdma: Increase the default connection credit limit
svcrdma: Remove try_module_get from backchannel
svcrdma: Remove ->release_rqst call in bc reply handler
svcrdma: Reduce max_send_sges
nfsd: fix fall-through annotations
knfsd: Improve lookup performance in the duplicate reply cache using an rbtree
knfsd: Further simplify the cache lookup
knfsd: Simplify NFS duplicate replay cache
knfsd: Remove dead code from nfsd_cache_lookup
SUNRPC: Simplify TCP receive code
SUNRPC: Replace the cache_detail->hash_lock with a regular spinlock
SUNRPC: Remove non-RCU protected lookup
NFS: Fix up a typo in nfs_dns_ent_put
NFS: Lockless DNS lookups
knfsd: Lockless lookup of NFSv4 identities.
SUNRPC: Lockless server RPCSEC_GSS context lookup
knfsd: Allow lockless lookups of the exports
...
Reduce queuing on clients by allowing more credits by default.
64 is the default NFSv4.1 slot table size on Linux clients. This
size prevents the credit limit from putting RPC requests to sleep
again after they have already slept waiting for a session slot.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Now that the reader functions are all RCU protected, use a regular
spinlock rather than a reader/writer lock.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Instead of the reader/writer spinlock, allow cache lookups to use RCU
for looking up entries. This is more efficient since modifications can
occur while other entries are being looked up.
Note that for now, we keep the reader/writer spinlock until all users
have been converted to use RCU-safe freeing of their cache entries.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Pull NFS client updates from Trond Myklebust:
"Highlights include:
Stable fixes:
- Fix the NFSv4.1 r/wsize sanity checking
- Reset the RPC/RDMA credit grant properly after a disconnect
- Fix a missed page unlock after pg_doio()
Features and optimisations:
- Overhaul of the RPC client socket code to eliminate a locking
bottleneck and reduce the latency when transmitting lots of
requests in parallel.
- Allow parallelisation of the RPCSEC_GSS encoding of an RPC request.
- Convert the RPC client socket receive code to use iovec_iter() for
improved efficiency.
- Convert several NFS and RPC lookup operations to use RCU instead of
taking global locks.
- Avoid the need for BH-safe locks in the RPC/RDMA back channel.
Bugfixes and cleanups:
- Fix lock recovery during NFSv4 delegation recalls
- Fix the NFSv4 + NFSv4.1 "lookup revalidate + open file" case.
- Fixes for the RPC connection metrics
- Various RPC client layer cleanups to consolidate stream based
sockets
- RPC/RDMA connection cleanups
- Simplify the RPC/RDMA cleanup after memory operation failures
- Clean ups for NFS v4.2 copy completion and NFSv4 open state
reclaim"
* tag 'nfs-for-4.20-1' of git://git.linux-nfs.org/projects/trondmy/linux-nfs: (97 commits)
SUNRPC: Convert the auth cred cache to use refcount_t
SUNRPC: Convert auth creds to use refcount_t
SUNRPC: Simplify lookup code
SUNRPC: Clean up the AUTH cache code
NFS: change sign of nfs_fh length
sunrpc: safely reallow resvport min/max inversion
nfs: remove redundant call to nfs_context_set_write_error()
nfs: Fix a missed page unlock after pg_doio()
SUNRPC: Fix a compile warning for cmpxchg64()
NFSv4.x: fix lock recovery during delegation recall
SUNRPC: use cmpxchg64() in gss_seq_send64_fetch_and_inc()
xprtrdma: Squelch a sparse warning
xprtrdma: Clean up xprt_rdma_disconnect_inject
xprtrdma: Add documenting comments
xprtrdma: Report when there were zero posted Receives
xprtrdma: Move rb_flags initialization
xprtrdma: Don't disable BH's in backchannel server
xprtrdma: Remove memory address of "ep" from an error message
xprtrdma: Rename rpcrdma_qp_async_error_upcall
xprtrdma: Simplify RPC wake-ups on connect
...
We no longer need to worry about whether or not the entry is hashed in
order to figure out if the contents are valid. We only care whether or
not the refcount is non-zero.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Avoid taking the global auth_domain_lock in most lookups of the auth domain
by adding an RCU protected lookup.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Add a bvec array to struct xdr_buf, and have the client allocate it
when we need to receive data into pages.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
If the RPC call relies on the receive call allocating pages as buffers,
then let's label it so that we
a) Don't leak memory by allocating pages for requests that do not expect
this behaviour
b) Can optimise for the common case where calls do not require allocation.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Fix up the priority queue to not batch by owner, but by queue, so that
we allow '1 << priority' elements to be dequeued before switching to
the next priority queue.
The owner field is still used to wake up requests in round robin order
by owner to avoid single processes hogging the RPC layer by loading the
queues.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
If the server is slow, we can find ourselves with quite a lot of entries
on the receive queue. Converting the search from an O(n) to O(log(n))
can make a significant difference, particularly since we have to hold
a number of locks while searching.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Treat socket write space handling in the same way we now treat transport
congestion: by denying the XPRT_LOCK until the transport signals that it
has free buffer space.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
The theory was that we would need to grab the socket lock anyway, so we
might as well use it to gate the allocation of RPC slots for a TCP
socket.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Both RDMA and UDP transports require the request to get a "congestion control"
credit before they can be transmitted. Right now, this is done when
the request locks the socket. We'd like it to happen when a request attempts
to be transmitted for the first time.
In order to support retransmission of requests that already hold such
credits, we also want to ensure that they get queued first, so that we
don't deadlock with requests that have yet to obtain a credit.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
One of the intentions with the priority queues was to ensure that no
single process can hog the transport. The field task->tk_owner therefore
identifies the RPC call's origin, and is intended to allow the RPC layer
to organise queues for fairness.
This commit therefore modifies the transmit queue to group requests
by task->tk_owner, and ensures that we round robin among those groups.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
