The variable error is ssize_t, which is signed and will
cast to unsigned when comapre with variable size, so add
a check to avoid unexpected result in case of negative
value of error.

Signed-off-by: Chengguang Xu <cgxu519@mykernel.net>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

Current behaviour: every time a v3 operation is re-sent to the server
we update (double) the timeout. There is no distinction between whether
or not the previous timer had expired before the re-sent happened.

Here's the scenario:
1. Client sends a v3 operation
2. Server RST-s the connection (prior to the timeout) (eg., connection
is immediately reset)
3. Client re-sends a v3 operation but the timeout is now 120sec.

As a result, an application sees 2mins pause before a retry in case
server again does not reply. Where as if a connection reset didn't
change the timeout value, the client would have re-tried (the 3rd
time) after 60secs.

Signed-off-by: Olga Kornievskaia <kolga@netapp.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

Request completion is already recorded by an "rpc_task_wakeup
queue=xprt_pending" trace record. A subsequent rpc_xdr_recvfrom
trace record shows the number of bytes received.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

Introduce a tracepoint in call_allocate that reports the exact
sizes in the RPC buffer allocation request and the status of the
result. This helps catch problems with XDR buffer provisioning,
and replaces transport-specific debugging instrumentation.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

These instruments don't appear to add any substantial value.

We already have this at the termination of each RPC:

          iozone-2617  [002]   975.713126: rpc_stats_latency:    task:418@5 xid=0x260eab5d nfsv3 LOOKUP backlog=15 rtt=32 execute=58
          iozone-2617  [002]   975.713127: xprt_release_cong:    task:418@5 snd_task:4294967295 cong=256 cwnd=16384
          iozone-2617  [002]   975.713127: xprt_put_cong:        task:418@5 snd_task:4294967295 cong=0 cwnd=16384

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

Replace a dprintk() with a tracepoint. The tracepoint marks the
point where an RPC request is assigned an XID.

Additional clean up: Remove trace_xprt_enq_xmit, which reports much
the same thing. That tracepoint was added for debugging commit
918f3c1 ("SUNRPC: Improve latency for interactive tasks").

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

Generate a trace event when an RPC request is queued without being
sent immediately.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

"no socket space" is an exceptional and infrequent condition
that troubleshooters want to know about.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

Clean up: The rpc_task_run_action tracepoint serves the same
purpose.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

Clean up: The rpc_rpc_request tracepoint serves the same purpose.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

This trace event can be used to audit transport connections from the
client.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

The original purpose of this expensive call is to prevent a long
queue of requests from blocking other work.

The cond_resched() call is unnecessary after just a single send
operation.

For longer queues, instead of invoking the kernel scheduler, simply
release the transport send lock and return to the RPC scheduler.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

For a long while we've wanted a tracepoint that fires when a major
timeout is reported in the system log. Such a tracepoint can be
attached to other actions that can take place when a timeout is
detected (eg, server or connection health assessment).

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

Clean up: Replace dprintk call sites.

Note that rpc_call_rpcerror() already has a trace point, so perhaps
adding trace_rpc_refresh_status() isn't necessary. However, it does
report a particular category of error.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

Clean up.

When enabled, this dprintk adds a line in /var/log/messages after
every RPC that reports the task ID (no connection to on the wire
XID values) and the RPC's result (no connection to the program,
operation, or the arguments and results).

Thus it's value is pretty low. Let's remove it.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

Time to remove dprintk call sites in here.

Regarding the rpc_bind_status tracepoint: It's friendlier to
administrators if they don't have to look up the error code to
figure out what went wrong. Replace trace_rpc_bind_status with a
set of tracepoints that report more specifically what the problem
was, and what RPC program/version was being queried.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

In many cases, tracepoints already report these errors. In others,
the dprintks were mainly useful when this code was less mature.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

Clean up: Other XDR functions no longer have dprintk call sites.
These were added during development and can be removed now that
the code is mature.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

Clean up: These are superfluous now that rpc_create() and friends
have tracepoints to report errors.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

In many cases, tracepoints already report these errors. In others,
the dprintks were mainly useful when this code was less mature.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

Remove several redundant dprintk call sites, and replace a couple of
potentially useful ones with tracepoints.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

Remove redundant call sites or call sites that are already covered
by tracepoints.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

Clean up.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

Change "time time" to "time expiry_time" to match the field name.

Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: "J. Bruce Fields" <bfields@fieldses.org>
Cc: Chuck Lever <chuck.lever@oracle.com>
Cc: Trond Myklebust <trond.myklebust@hammerspace.com>
Cc: Anna Schumaker <anna.schumaker@netapp.com>
Cc: linux-nfs@vger.kernel.org
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

Rationale:
Reduces attack surface on kernel devs opening the links for MITM
as HTTPS traffic is much harder to manipulate.

Deterministic algorithm:
For each file:
  If not .svg:
    For each line:
      If doesn't contain `\bxmlns\b`:
        For each link, `\bhttp://[^# \t\r\n]*(?:\w|/)`:
          If both the HTTP and HTTPS versions
          return 200 OK and serve the same content:
            Replace HTTP with HTTPS.

Signed-off-by: Alexander A. Klimov <grandmaster@al2klimov.de>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

The following oops is seen during xfstest/565 when the 'test'
(source of the copy) is NFS4.0 and 'scratch' (destination) is NFS4.2
[   59.692458] run fstests generic/565 at 2020-08-01 05:50:35
[   60.613588] BUG: kernel NULL pointer dereference, address: 0000000000000008
[   60.624970] #PF: supervisor read access in kernel mode
[   60.627671] #PF: error_code(0x0000) - not-present page
[   60.630347] PGD 0 P4D 0
[   60.631853] Oops: 0000 [#1] SMP PTI
[   60.634086] CPU: 6 PID: 2828 Comm: xfs_io Kdump: loaded Not tainted 5.8.0-rc3 #1
[   60.637676] Hardware name: Red Hat KVM, BIOS 0.5.1 01/01/2011
[   60.639901] RIP: 0010:nfs4_check_serverowner_major_id+0x5/0x30 [nfsv4]
[   60.642719] Code: 89 ff e8 3e b3 b8 e1 e9 71 fe ff ff 41 bc da d8 ff ff e9 c3 fe ff ff e8 e9 9d 08 e2 66 0f 1f 84 00 00 00 00 00 66 66 66 66 90 <8b> 57 08 31 c0 3b 56 08 75 12 48 83 c6 0c 48 83 c7 0c e8 c4 97 bb
[   60.652629] RSP: 0018:ffffc265417f7e10 EFLAGS: 00010287
[   60.655379] RAX: ffffa0664b066400 RBX: 0000000000000000 RCX: 0000000000000001
[   60.658754] RDX: ffffa066725fb000 RSI: ffffa066725fd000 RDI: 0000000000000000
[   60.662292] RBP: 0000000000020000 R08: 0000000000020000 R09: 0000000000000000
[   60.666189] R10: 0000000000000003 R11: 0000000000000000 R12: ffffa06648258d00
[   60.669914] R13: 0000000000000000 R14: 0000000000000000 R15: ffffa06648258100
[   60.673645] FS:  00007faa9fb35800(0000) GS:ffffa06677d80000(0000) knlGS:0000000000000000
[   60.677698] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   60.680773] CR2: 0000000000000008 CR3: 0000000203f14000 CR4: 00000000000406e0
[   60.684476] Call Trace:
[   60.685809]  nfs4_copy_file_range+0xfc/0x230 [nfsv4]
[   60.688704]  vfs_copy_file_range+0x2ee/0x310
[   60.691104]  __x64_sys_copy_file_range+0xd6/0x210
[   60.693527]  do_syscall_64+0x4d/0x90
[   60.695512]  entry_SYSCALL_64_after_hwframe+0x44/0xa9
[   60.698006] RIP: 0033:0x7faa9febc1bd

Signed-off-by: Dave Wysochanski <dwysocha@redhat.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

Convert the uses of fallthrough comments to fallthrough macro. Please see
commit 294f69e ("compiler_attributes.h: Add 'fallthrough' pseudo
keyword for switch/case use") for detail.

Signed-off-by: Hongxiang Lou <louhongxiang@huawei.com>
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

The hash_lock field of the cache structure was a leftover
of a previous iteration of the code. It is now unused,
so remove it.

Signed-off-by: Frank van der Linden <fllinden@amazon.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

RFC 7862 introduced a new flag that either client or server is
allowed to set: EXCHGID4_FLAG_SUPP_FENCE_OPS.

Client needs to update its bitmask to allow for this flag value.

v2: changed minor version argument to unsigned int

Signed-off-by: Olga Kornievskaia <kolga@netapp.com>
CC: <stable@vger.kernel.org>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

An incorrect sizeof() is being used, sizeof(file_data->table) is not
correct, it should be sizeof(*file_data->table).

Fixes: 5398ae6 ("io_uring: clean file_data access in files_register")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Addresses-Coverity: ("Sizeof not portable (SIZEOF_MISMATCH)")
Signed-off-by: Jens Axboe <axboe@kernel.dk>

__io_kill_linked_timeout() sets REQ_F_COMP_LOCKED for a linked timeout
even if it can't cancel it, e.g. it's already running. It not only races
with io_link_timeout_fn() for ->flags field, but also leaves the flag
set and so io_link_timeout_fn() may find it and decide that it holds the
lock. Hopefully, the second problem is potential.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

If a request had REQ_F_LINK_TIMEOUT it would've been cleared in
__io_kill_linked_timeout() by the time of __io_fail_links(), so no need
to care about it.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Move io_put_req() in io_poll_task_handler() from under spinlock. This
eliminates the need to use REQ_F_COMP_LOCKED, at the expense of
potentially having to grab the lock again. That's still a better trade
off than relying on the locked flag.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

io_req_clean_work() checks REQ_F_COMP_LOCK to pass this two layers up.
Move the check up into __io_free_req(), so at least it doesn't looks so
ugly and would facilitate further changes.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

REQ_F_COMP_LOCKED is used and implemented in a buggy way. The problem is
that the flag is set before io_put_req() but not cleared after, and if
that wasn't the final reference, the request will be freed with the flag
set from some other context, which may not hold a spinlock. That means
possible races with removing linked timeouts and unsynchronised
completion (e.g. access to CQ).

Instead of fixing REQ_F_COMP_LOCKED, kill the flag and use
task_work_add() to move such requests to a fresh context to free from
it, as was done with __io_free_req_finish().

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

This reverts commit 738277a.

This change didn't make a lot of sense, and as Linus reports, it actually
fails on clang:

   /tmp/io_uring-dd40c4.s:26476: Warning: ignoring changed section
   attributes for .data..read_mostly

The arrays are already marked const so, by definition, they are not
just read-mostly, they are read-only.

Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

syzbot reports the following crash:

general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
CPU: 1 PID: 8927 Comm: syz-executor.3 Not tainted 5.9.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:io_file_from_index fs/io_uring.c:5963 [inline]
RIP: 0010:io_sqe_files_register fs/io_uring.c:7369 [inline]
RIP: 0010:__io_uring_register fs/io_uring.c:9463 [inline]
RIP: 0010:__do_sys_io_uring_register+0x2fd2/0x3ee0 fs/io_uring.c:9553
Code: ec 03 49 c1 ee 03 49 01 ec 49 01 ee e8 57 61 9c ff 41 80 3c 24 00 0f 85 9b 09 00 00 4d 8b af b8 01 00 00 4c 89 e8 48 c1 e8 03 <80> 3c 28 00 0f 85 76 09 00 00 49 8b 55 00 89 d8 c1 f8 09 48 98 4c
RSP: 0018:ffffc90009137d68 EFLAGS: 00010246
RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffc9000ef2a000
RDX: 0000000000040000 RSI: ffffffff81d81dd9 RDI: 0000000000000005
RBP: dffffc0000000000 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: ffffed1012882a37
R13: 0000000000000000 R14: ffffed1012882a38 R15: ffff888094415000
FS:  00007f4266f3c700(0000) GS:ffff8880ae500000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000000118c000 CR3: 000000008e57d000 CR4: 00000000001506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x45de59
Code: 0d b4 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 db b3 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f4266f3bc78 EFLAGS: 00000246 ORIG_RAX: 00000000000001ab
RAX: ffffffffffffffda RBX: 00000000000083c0 RCX: 000000000045de59
RDX: 0000000020000280 RSI: 0000000000000002 RDI: 0000000000000005
RBP: 000000000118bf68 R08: 0000000000000000 R09: 0000000000000000
R10: 40000000000000a1 R11: 0000000000000246 R12: 000000000118bf2c
R13: 00007fff2fa4f12f R14: 00007f4266f3c9c0 R15: 000000000118bf2c
Modules linked in:
---[ end trace 2a40a195e2d5e6e6 ]---
RIP: 0010:io_file_from_index fs/io_uring.c:5963 [inline]
RIP: 0010:io_sqe_files_register fs/io_uring.c:7369 [inline]
RIP: 0010:__io_uring_register fs/io_uring.c:9463 [inline]
RIP: 0010:__do_sys_io_uring_register+0x2fd2/0x3ee0 fs/io_uring.c:9553
Code: ec 03 49 c1 ee 03 49 01 ec 49 01 ee e8 57 61 9c ff 41 80 3c 24 00 0f 85 9b 09 00 00 4d 8b af b8 01 00 00 4c 89 e8 48 c1 e8 03 <80> 3c 28 00 0f 85 76 09 00 00 49 8b 55 00 89 d8 c1 f8 09 48 98 4c
RSP: 0018:ffffc90009137d68 EFLAGS: 00010246
RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffc9000ef2a000
RDX: 0000000000040000 RSI: ffffffff81d81dd9 RDI: 0000000000000005
RBP: dffffc0000000000 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: ffffed1012882a37
R13: 0000000000000000 R14: ffffed1012882a38 R15: ffff888094415000
FS:  00007f4266f3c700(0000) GS:ffff8880ae400000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000000074a918 CR3: 000000008e57d000 CR4: 00000000001506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400

which is a copy of fget failure condition jumping to cleanup, but the
cleanup requires ctx->file_data to be assigned. Assign it when setup,
and ensure that we clear it again for the error path exit.

Fixes: 5398ae6 ("io_uring: clean file_data access in files_register")
Reported-by: syzbot+f4ebcc98223dafd8991e@syzkaller.appspotmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

There was an assumption that kthread_create_on_node() would properly set
NUMA affinities in terms of CPUs allowed, but it doesn't. Make sure we
do this when creating an io-wq context on NUMA.

Cc: stable@vger.kernel.org
Stefan Metzmacher <metze@samba.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

We have a number of bits that decide what context to inherit. Set up
io-wq flags for these instead. This is in preparation for always having
the various members set, but not always needing them for all requests.

No intended functional changes in this patch.

Signed-off-by: Jens Axboe <axboe@kernel.dk>

We solely rely on work->work_flags now, so use that for proper checking
and clearing/dropping of various identity items.

Signed-off-by: Jens Axboe <axboe@kernel.dk>

io-wq contains a pointer to the identity, which we just hold in io_kiocb
for now. This is in preparation for putting this outside io_kiocb. The
only exception is struct files_struct, which we'll need different rules
for to avoid a circular dependency.

No functional changes in this patch.

Signed-off-by: Jens Axboe <axboe@kernel.dk>

If the io_identity doesn't completely match the task, then create a
copy of it and use that. The existing copy remains valid until the last
user of it has gone away.

This also changes the personality lookup to be indexed by io_identity,
instead of creds directly.

Signed-off-by: Jens Axboe <axboe@kernel.dk>

This is, by definition, a per-task structure. So store it in the
task context, instead of doing carrying it in each io_kiocb. We're being
a bit inefficient if members have changed, as that requires an alloc and
copy of a new io_identity struct. The next patch will fix that up.

Signed-off-by: Jens Axboe <axboe@kernel.dk>

This avoids doing a copy for each new async IO, if some parts of the
io_identity has changed. We avoid reference counting for the normal
fast path of nothing ever changing.

Signed-off-by: Jens Axboe <axboe@kernel.dk>

Even though we place the req_issued and req_complete in separate
cachelines, there's considerable overhead in doing the atomics
particularly on the completion side.

Get rid of having the two counters, and just use a percpu_counter for
this. That's what it was made for, after all. This considerably
reduces the overhead in __io_free_req().

Signed-off-by: Jens Axboe <axboe@kernel.dk>

Make sure the async io-wq workers inherit the loginuid and sessionid from
the original task, and restore them to unset once we're done with the
async work item.

While at it, disable the ability for kernel threads to write to their own
loginuid.

Signed-off-by: Jens Axboe <axboe@kernel.dk>

__io_queue_proc() is used by both, poll reqs and apoll. Don't use
req->poll.events to copy poll mask because for apoll it aliases with
private data of the request.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Once we've copied some data for an iocb that is marked with IOCB_WAITQ,
we should no longer attempt to async lock a new page. Instead make sure
we return the copied amount, and let the caller retry, instead of
returning -EIOCBQUEUED for a new page.

This should only be possible with read-ahead disabled on the below
device, and multiple threads racing on the same file. Haven't been able
to reproduce on anything else.

Cc: stable@vger.kernel.org # v5.9
Fixes: 1a0a785 ("mm: support async buffered reads in generic_file_buffered_read()")
Reported-by: Kent Overstreet <kent.overstreet@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

For the case where read-ahead is disabled on the file, or if the cgroup
is congested, ensure that we can at least do 1 page of read-ahead to
make progress on the read in an async fashion. This could potentially be
larger, but it's not needed in terms of functionality, so let's error on
the side of caution as larger counts of pages may run into reclaim
issues (particularly if we're congested).

This makes sure we're not hitting the potentially sync ->readpage() path
for IO that is marked IOCB_WAITQ, which could cause us to block. It also
means we'll use the same path for IO, regardless of whether or not
read-ahead happens to be disabled on the lower level device.

Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Reported-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reported-by: Hao_Xu <haoxu@linux.alibaba.com>
[axboe: updated for new ractl API]
Signed-off-by: Jens Axboe <axboe@kernel.dk>

commit 021a244 ("block: add QUEUE_FLAG_NOWAIT") adds a new helper
function blk_queue_nowait() to check if the bdev supports handling of
REQ_NOWAIT or not. Since then bio-based dm device can also support
REQ_NOWAIT, and currently only dm-linear supports that since
commit 6abc494 ("dm: add support for REQ_NOWAIT and enable it for
linear target").

Signed-off-by: Jeffle Xu <jefflexu@linux.alibaba.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Pull io_uring updates from Jens Axboe:
 "A mix of fixes and a few stragglers. In detail:

   - Revert the bogus __read_mostly that we discussed for the initial
     pull request.

   - Fix a merge window regression with fixed file registration error
     path handling.

   - Fix io-wq numa node affinities.

   - Series abstracting out an io_identity struct, making it both easier
     to see what the personality items are, and also easier to to adopt
     more. Use this to cover audit logging.

   - Fix for read-ahead disabled block condition in async buffered
     reads, and using single page read-ahead to unify what
     generic_file_buffer_read() path is used.

   - Series for REQ_F_COMP_LOCKED fix and removal of it (Pavel)

   - Poll fix (Pavel)"

* tag 'io_uring-5.10-2020-10-20' of git://git.kernel.dk/linux-block: (21 commits)
  io_uring: use blk_queue_nowait() to check if NOWAIT supported
  mm: use limited read-ahead to satisfy read
  mm: mark async iocb read as NOWAIT once some data has been copied
  io_uring: fix double poll mask init
  io-wq: inherit audit loginuid and sessionid
  io_uring: use percpu counters to track inflight requests
  io_uring: assign new io_identity for task if members have changed
  io_uring: store io_identity in io_uring_task
  io_uring: COW io_identity on mismatch
  io_uring: move io identity items into separate struct
  io_uring: rely solely on work flags to determine personality.
  io_uring: pass required context in as flags
  io-wq: assign NUMA node locality if appropriate
  io_uring: fix error path cleanup in io_sqe_files_register()
  Revert "io_uring: mark io_uring_fops/io_op_defs as __read_mostly"
  io_uring: fix REQ_F_COMP_LOCKED by killing it
  io_uring: dig out COMP_LOCK from deep call chain
  io_uring: don't put a poll req under spinlock
  io_uring: don't unnecessarily clear F_LINK_TIMEOUT
  io_uring: don't set COMP_LOCKED if won't put
  ...

…inux-nfs

Pull NFS client updates from Anna Schumaker:
 "Stable Fixes:
   - Wait for stateid updates after CLOSE/OPEN_DOWNGRADE # v5.4+
   - Fix nfs_path in case of a rename retry
   - Support EXCHID4_FLAG_SUPP_FENCE_OPS v4.2 EXCHANGE_ID flag

  New features and improvements:
   - Replace dprintk() calls with tracepoints
   - Make cache consistency bitmap dynamic
   - Added support for the NFS v4.2 READ_PLUS operation
   - Improvements to net namespace uniquifier

  Other bugfixes and cleanups:
   - Remove redundant clnt pointer
   - Don't update timeout values on connection resets
   - Remove redundant tracepoints
   - Various cleanups to comments
   - Fix oops when trying to use copy_file_range with v4.0 source server
   - Improvements to flexfiles mirrors
   - Add missing 'local_lock=posix' mount option"

* tag 'nfs-for-5.10-1' of git://git.linux-nfs.org/projects/anna/linux-nfs: (55 commits)
  NFSv4.2: support EXCHGID4_FLAG_SUPP_FENCE_OPS 4.2 EXCHANGE_ID flag
  NFSv4: Fix up RCU annotations for struct nfs_netns_client
  NFS: Only reference user namespace from nfs4idmap struct instead of cred
  nfs: add missing "posix" local_lock constant table definition
  NFSv4: Use the net namespace uniquifier if it is set
  NFSv4: Clean up initialisation of uniquified client id strings
  NFS: Decode a full READ_PLUS reply
  SUNRPC: Add an xdr_align_data() function
  NFS: Add READ_PLUS hole segment decoding
  SUNRPC: Add the ability to expand holes in data pages
  SUNRPC: Split out _shift_data_right_tail()
  SUNRPC: Split out xdr_realign_pages() from xdr_align_pages()
  NFS: Add READ_PLUS data segment support
  NFS: Use xdr_page_pos() in NFSv4 decode_getacl()
  SUNRPC: Implement a xdr_page_pos() function
  SUNRPC: Split out a function for setting current page
  NFS: fix nfs_path in case of a rename retry
  fs: nfs: return per memcg count for xattr shrinkers
  NFSv4: Wait for stateid updates after CLOSE/OPEN_DOWNGRADE
  nfs: remove incorrect fallthrough label
  ...

Pull XArray updates from Matthew Wilcox:

 - Fix the test suite after introduction of the local_lock

 - Fix a bug in the IDA spotted by Coverity

 - Change the API that allows the workingset code to delete a node

 - Fix xas_reload() when dealing with entries that occupy multiple
   indices

 - Add a few more tests to the test suite

 - Fix an unsigned int being shifted into an unsigned long

* tag 'xarray-5.9' of git://git.infradead.org/users/willy/xarray:
  XArray: Fix xas_create_range for ranges above 4 billion
  radix-tree: fix the comment of radix_tree_next_slot()
  XArray: Fix xas_reload for multi-index entries
  XArray: Add private interface for workingset node deletion
  XArray: Fix xas_for_each_conflict documentation
  XArray: Test marked multiorder iterations
  XArray: Test two more things about xa_cmpxchg
  ida: Free allocated bitmap in error path
  radix tree test suite: Fix compilation