We recently fixed lease breaking so that a client's actions won't break
its own delegations.

But we still have an unnecessary self-conflict when granting
delegations: a client's own write opens will prevent us from handing out
a read delegation even when no other client has the file open for write.

Fix that by turning off the checks for conflicting opens under
vfs_setlease, and instead performing those checks in the nfsd code.

We don't depend much on locks here: instead we acquire the delegation,
then check for conflicts, and drop the delegation again if we find any.

The check beforehand is an optimization of sorts, just to avoid
acquiring the delegation unnecessarily.  There's a race where the first
check could cause us to deny the delegation when we could have granted
it.  But, that's OK, delegation grants are optional (and probably not
even a good idea in that case).
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

A single character (line break) should be put into a sequence.
Thus use the corresponding function "seq_putc()".
Signed-off-by: Xu Wang <vulab@iscas.ac.cn>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

Re-use the post_rw tracepoint (safely) to trace cc_info lifetime
events, including completion IDs.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

First, refactor: Dereference the svc_rdma_send_ctxt inside
svc_rdma_send() instead of at every call site.

Then, it can be passed into trace_svcrdma_post_send() to get the
proper completion ID.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

Set up a completion ID in each svc_rdma_send_ctxt. The ID is used
to match an incoming Send completion to a transport and to a
previous ib_post_send().
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

When recording a trace event in the Receive path, tie decoding
results and errors to an incoming Receive completion.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

Set up a completion ID in each svc_rdma_recv_ctxt. The ID is used
to match an incoming Receive completion to a transport and to a
previous ib_post_recv().
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

The goal is to replace CQE kernel memory addresses in completion-
related tracepoints.

Each completion ID matches an incoming Send or Receive completion
to a Completion Queue and to a previous ib_post_*(). The ID can
then be displayed in an error message or recorded in a trace
record.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

Clean up: De-duplicate some code.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

Clean up: De-duplicate some code.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

Use these helpers in a few spots to demonstrate their use.

The remaining open-coded discriminator checks in rpcrdma will be
addressed in subsequent patches.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

Pavane pour une infante défunte.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

- Use the _err naming convention instead
- Remove display of kernel memory address of the controlling xprt
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

Final refactor: Replace internals of svc_rdma_send_error() with a
simple call to svc_rdma_send_error_msg().
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

Prepare for svc_rdma_send_error_msg() to be invoked from another
source file.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

Like svc_rdma_send_error(), have svc_rdma_send_error_msg() handle
any error conditions internally, rather than duplicating that
recovery logic at every call site.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

The common "send RDMA_ERR" function should be in svc_rdma_sendto.c,
since that is where the other Send-related functions are located.
So from here, I will beef up svc_rdma_send_error_msg() and deprecate
svc_rdma_send_error().

A generic svc_rdma_send_error_msg() will need to handle both
ERR_CHUNK and ERR_VERS. Copy that logic from svc_rdma_send_error()
to svc_rdma_send_error_msg().
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

Another step towards making svc_rdma_send_error_msg() and
svc_rdma_send_error() similar enough to eliminate one of them.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

Commit 4757d90b ("svcrdma: Report Write/Reply chunk overruns")
made an effort to preserve I/O pages until RDMA Write completion.

In a subsequent patch, I intend to de-duplicate the two functions
that send ERR_CHUNK responses. Pull the save_io_pages() call out of
svc_rdma_send_error_msg() to make it more like
svc_rdma_send_error().
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

Commit 07d0ff3b ("svcrdma: Clean up Read chunk path") moved the
page saver logic so that it gets executed event when an error occurs.
In that case, the I/O is never posted, and those pages are then
leaked. Errors in this path, however, are quite rare.

Fixes: 07d0ff3b ("svcrdma: Clean up Read chunk path")
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

Add similar tracepoints to those that were recently added on the
client side to track failures in the integ and priv unwrap paths.

And, let's collect the seqno-specific tracepoints together with a
common naming convention.

Regarding the gss_check_seq_num() changes: everywhere else treats
the GSS sequence number as an unsigned 32-bit integer. As far back
as 2.6.12, I couldn't find a compelling reason to do things
differently here. As a defensive change it's better to eliminate
needless implicit sign conversions.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

Check if user extended attributes are supported for an inode,
and return the answer when being queried for file attributes.

An exported filesystem can now signal its RFC8276 user extended
attributes capability.
Signed-off-by: Frank van der Linden <fllinden@amazon.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

Implement the main entry points for the *XATTR operations.

Add functions to calculate the reply size for the user extended attribute
operations, and implement the XDR encode / decode logic for these
operations.

Add the user extended attributes operations to nfsd4_ops.
Signed-off-by: Frank van der Linden <fllinden@amazon.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

Add the structures used in extended attribute request / response handling.
Signed-off-by: Frank van der Linden <fllinden@amazon.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

Since the NFSv4.2 extended attributes extension defines 3 new access
bits for xattr operations, take them in to account when validating
what the client is asking for, and when checking permissions.
Signed-off-by: Frank van der Linden <fllinden@amazon.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

This adds the filehandle based functions for the xattr operations
that call in to the vfs layer to do the actual work.
Signed-off-by: Frank van der Linden <fllinden@amazon.com>
[ cel: address checkpatch.pl complaint ]
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

Add defines for server-side extended attribute support. Most have
already been added as part of client support, but these are
the network order error codes for the noxattr and xattr2big errors,
and the addition of the xattr support to the supported file
attributes (if configured).
Signed-off-by: Frank van der Linden <fllinden@amazon.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

nfs4_decode_write has code to parse incoming XDR write data in to
a kvec head, and a list of pages.

Put this code in to a separate function, so that it can be used
later by the xattr code, for setxattr. No functional change.
Signed-off-by: Frank van der Linden <fllinden@amazon.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

Add a function that checks is an extended attribute namespace is
supported for an inode, meaning that a handler must be present
for either the whole namespace, or at least one synthetic
xattr in the namespace.

To be used by the nfs server code when being queried for extended
attributes support.

Cc: linux-fsdevel@vger.kernel.org
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Frank van der Linden <fllinden@amazon.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

set/removexattr on an exported filesystem should break NFS delegations.
This is true in general, but also for the upcoming support for
RFC 8726 (NFSv4 extended attribute support). Make sure that they do.

Additionally, they need to grow a _locked variant, since callers might
call this with i_rwsem held (like the NFS server code).

Cc: stable@vger.kernel.org # v4.9+
Cc: linux-fsdevel@vger.kernel.org
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Frank van der Linden <fllinden@amazon.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

Add definitions for the new operations, errors and flags as defined
in RFC 8276 (File System Extended Attributes in NFSv4).
Signed-off-by: Frank van der Linden <fllinden@amazon.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

Pull Xtensa fixes from Max Filippov:

 - fix __sync_fetch_and_{and,or}_4 declarations to avoid build warning

 - update *pos in cpuinfo_op.next to avoid runtime warning

 - use for_each_set_bit in xtensa_pmu_irq_handler instead of open-coding
   it

* tag 'xtensa-20200712' of git://github.com/jcmvbkbc/linux-xtensa:
  xtensa: simplify xtensa_pmu_irq_handler
  xtensa: update *pos in cpuinfo_op.next
  xtensa: fix __sync_fetch_and_{and,or}_4 declarations

Pull io_uring fixes from Jens Axboe:
 "Two late fixes again:

   - Fix missing msg_name assignment in certain cases (Pavel)

   - Correct a previous fix for full coverage (Pavel)"

* tag 'io_uring-5.8-2020-07-12' of git://git.kernel.dk/linux-block:
  io_uring: fix not initialised work->flags
  io_uring: fix missing msg_name assignment

Pull btrfs fixes from David Sterba:
 "Two refcounting fixes and one prepartory patch for upcoming splice
  cleanup:

   - fix double put of block group with nodatacow

   - fix missing block group put when remounting with discard=async

   - explicitly set splice callback (no functional change), to ease
     integrating splice cleanup patches"

* tag 'for-5.8-rc4-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
  btrfs: wire up iter_file_splice_write
  btrfs: fix double put of block group with nocow
  btrfs: discard: add missing put when grabbing block group from unused list

59960b9d ("io_uring: fix lazy work init") tried to fix missing
io_req_init_async(), but left out work.flags and hash. Do it earlier.

Fixes: 7cdaf587 ("io_uring: avoid whole io_wq_work copy for requests completed inline")
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Ensure to set msg.msg_name for the async portion of send/recvmsg,
as the header copy will copy to/from it.

Cc: stable@vger.kernel.org # v5.5+
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Pull RISC-V fixes from Palmer Dabbelt:
 "I have a few KGDB-related fixes. They're mostly fixes for build
  warnings, but there's also:

   - Support for the qSupported and qXfer packets, which are necessary
     to pass around GDB XML information which we need for the RISC-V GDB
     port to fully function.

   - Users can now select STRICT_KERNEL_RWX instead of forcing it on"

* tag 'riscv-for-linus-5.8-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux:
  riscv: Avoid kgdb.h including gdb_xml.h to solve unused-const-variable warning
  kgdb: Move the extern declaration kgdb_has_hit_break() to generic kgdb.h
  riscv: Fix "no previous prototype" compile warning in kgdb.c file
  riscv: enable the Kconfig prompt of STRICT_KERNEL_RWX
  kgdb: enable arch to support XML packet.

Pull SCSI fixes from James Bottomley:
 "Five small fixes, four in driver and one in the SCSI Parallel
  transport, which fixes an incredibly old bug so I suspect no-one has
  actually used the functionality it fixes"

* tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi:
  scsi: dh: Add Fujitsu device to devinfo and dh lists
  scsi: mpt3sas: Fix error returns in BRM_status_show
  scsi: mpt3sas: Fix unlock imbalance
  scsi: iscsi: Change iSCSI workqueue max_active back to 1
  scsi: scsi_transport_spi: Fix function pointer check

Pull xen fix from Juergen Gross:
 "Just one fix of a recent patch (double free in an error path)"

* tag 'for-linus-5.8b-rc5-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
  xen/xenbus: Fix a double free in xenbus_map_ring_pv()