If we reach the limit of modprobe_limit threads running the next
request_module() call will fail.  The original reason for adding a kill
was to do away with possible issues with in old circumstances which would
create a recursive series of request_module() calls.

We can do better than just be super aggressive and reject calls once we've
reached the limit by simply making pending callers wait until the
threshold has been reduced, and then throttling them in, one by one.

This throttling enables requests over the kmod concurrent limit to be
processed once a pending request completes.  Only the first item queued up
to wait is woken up.  The assumption here is once a task is woken it will
have no other option to also kick the queue to check if there are more
pending tasks -- regardless of whether or not it was successful.

By throttling and processing only max kmod concurrent tasks we ensure we
avoid unexpected fatal request_module() calls, and we keep memory
consumption on module loading to a minimum.

With x86_64 qemu, with 4 cores, 4 GiB of RAM it takes the following run
time to run both tests:

time ./kmod.sh -t 0008
real    0m16.366s
user    0m0.883s
sys     0m8.916s

time ./kmod.sh -t 0009
real    0m50.803s
user    0m0.791s
sys     0m9.852s

Link: http://lkml.kernel.org/r/20170628223155.26472-4-mcgrof@kernel.orgSigned-off-by: NLuis R. Rodriguez <mcgrof@kernel.org>
Reviewed-by: NPetr Mladek <pmladek@suse.com>
Cc: Jessica Yu <jeyu@redhat.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Michal Marek <mmarek@suse.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This adds a new stress test driver for kmod: the kernel module loader.
The new stress test driver, test_kmod, is only enabled as a module right
now.  It should be possible to load this as built-in and load tests
early (refer to the force_init_test module parameter), however since a
lot of test can get a system out of memory fast we leave this disabled
for now.

Using a system with 1024 MiB of RAM can *easily* get your kernel OOM
fast with this test driver.

The test_kmod driver exposes API knobs for us to fine tune simple
request_module() and get_fs_type() calls.  Since these API calls only
allow each one parameter a test driver for these is rather simple.
Other factors that can help out test driver though are the number of
calls we issue and knowing current limitations of each.  This exposes
configuration as much as possible through userspace to be able to build
tests directly from userspace.

Since it allows multiple misc devices its will eventually (once we add a
knob to let us create new devices at will) also be possible to perform
more tests in parallel, provided you have enough memory.

We only enable tests we know work as of right now.

Demo screenshots:

 # tools/testing/selftests/kmod/kmod.sh
kmod_test_0001_driver: OK! - loading kmod test
kmod_test_0001_driver: OK! - Return value: 256 (MODULE_NOT_FOUND), expected MODULE_NOT_FOUND
kmod_test_0001_fs: OK! - loading kmod test
kmod_test_0001_fs: OK! - Return value: -22 (-EINVAL), expected -EINVAL
kmod_test_0002_driver: OK! - loading kmod test
kmod_test_0002_driver: OK! - Return value: 256 (MODULE_NOT_FOUND), expected MODULE_NOT_FOUND
kmod_test_0002_fs: OK! - loading kmod test
kmod_test_0002_fs: OK! - Return value: -22 (-EINVAL), expected -EINVAL
kmod_test_0003: OK! - loading kmod test
kmod_test_0003: OK! - Return value: 0 (SUCCESS), expected SUCCESS
kmod_test_0004: OK! - loading kmod test
kmod_test_0004: OK! - Return value: 0 (SUCCESS), expected SUCCESS
kmod_test_0005: OK! - loading kmod test
kmod_test_0005: OK! - Return value: 0 (SUCCESS), expected SUCCESS
kmod_test_0006: OK! - loading kmod test
kmod_test_0006: OK! - Return value: 0 (SUCCESS), expected SUCCESS
kmod_test_0005: OK! - loading kmod test
kmod_test_0005: OK! - Return value: 0 (SUCCESS), expected SUCCESS
kmod_test_0006: OK! - loading kmod test
kmod_test_0006: OK! - Return value: 0 (SUCCESS), expected SUCCESS
XXX: add test restult for 0007
Test completed

You can also request for specific tests:

 # tools/testing/selftests/kmod/kmod.sh -t 0001
kmod_test_0001_driver: OK! - loading kmod test
kmod_test_0001_driver: OK! - Return value: 256 (MODULE_NOT_FOUND), expected MODULE_NOT_FOUND
kmod_test_0001_fs: OK! - loading kmod test
kmod_test_0001_fs: OK! - Return value: -22 (-EINVAL), expected -EINVAL
Test completed

Lastly, the current available number of tests:

 # tools/testing/selftests/kmod/kmod.sh --help
Usage: tools/testing/selftests/kmod/kmod.sh [ -t <4-number-digit> ]
Valid tests: 0001-0009

0001 - Simple test - 1 thread  for empty string
0002 - Simple test - 1 thread  for modules/filesystems that do not exist
0003 - Simple test - 1 thread  for get_fs_type() only
0004 - Simple test - 2 threads for get_fs_type() only
0005 - multithreaded tests with default setup - request_module() only
0006 - multithreaded tests with default setup - get_fs_type() only
0007 - multithreaded tests with default setup test request_module() and get_fs_type()
0008 - multithreaded - push kmod_concurrent over max_modprobes for request_module()
0009 - multithreaded - push kmod_concurrent over max_modprobes for get_fs_type()

The following test cases currently fail, as such they are not currently
enabled by default:

 # tools/testing/selftests/kmod/kmod.sh -t 0008
 # tools/testing/selftests/kmod/kmod.sh -t 0009

To be sure to run them as intended please unload both of the modules:

  o test_module
  o xfs

And ensure they are not loaded on your system prior to testing them.  If
you use these paritions for your rootfs you can change the default test
driver used for get_fs_type() by exporting it into your environment.  For
example of other test defaults you can override refer to kmod.sh
allow_user_defaults().

Behind the scenes this is how we fine tune at a test case prior to
hitting a trigger to run it:

cat /sys/devices/virtual/misc/test_kmod0/config
echo -n "2" > /sys/devices/virtual/misc/test_kmod0/config_test_case
echo -n "ext4" > /sys/devices/virtual/misc/test_kmod0/config_test_fs
echo -n "80" > /sys/devices/virtual/misc/test_kmod0/config_num_threads
cat /sys/devices/virtual/misc/test_kmod0/config
echo -n "1" > /sys/devices/virtual/misc/test_kmod0/config_num_threads

Finally to trigger:

echo -n "1" > /sys/devices/virtual/misc/test_kmod0/trigger_config

The kmod.sh script uses the above constructs to build different test cases.

A bit of interpretation of the current failures follows, first two
premises:

a) When request_module() is used userspace figures out an optimized
   version of module order for us.  Once it finds the modules it needs, as
   per depmod symbol dep map, it will finit_module() the respective
   modules which are needed for the original request_module() request.

b) We have an optimization in place whereby if a kernel uses
   request_module() on a module already loaded we never bother userspace
   as the module already is loaded.  This is all handled by kernel/kmod.c.

A few things to consider to help identify root causes of issues:

0) kmod 19 has a broken heuristic for modules being assumed to be
   built-in to your kernel and will return 0 even though request_module()
   failed.  Upgrade to a newer version of kmod.

1) A get_fs_type() call for "xfs" will request_module() for "fs-xfs",
   not for "xfs".  The optimization in kernel described in b) fails to
   catch if we have a lot of consecutive get_fs_type() calls.  The reason
   is the optimization in place does not look for aliases.  This means two
   consecutive get_fs_type() calls will bump kmod_concurrent, whereas
   request_module() will not.

This one explanation why test case 0009 fails at least once for
get_fs_type().

2) If a module fails to load --- for whatever reason (kmod_concurrent
   limit reached, file not yet present due to rootfs switch, out of
   memory) we have a period of time during which module request for the
   same name either with request_module() or get_fs_type() will *also*
   fail to load even if the file for the module is ready.

This explains why *multiple* NULLs are possible on test 0009.

3) finit_module() consumes quite a bit of memory.

4) Filesystems typically also have more dependent modules than other
   modules, its important to note though that even though a get_fs_type()
   call does not incur additional kmod_concurrent bumps, since userspace
   loads dependencies it finds it needs via finit_module_fd(), it *will*
   take much more memory to load a module with a lot of dependencies.

Because of 3) and 4) we will easily run into out of memory failures with
certain tests.  For instance test 0006 fails on qemu with 1024 MiB of RAM.
It panics a box after reaping all userspace processes and still not
having enough memory to reap.

[arnd@arndb.de: add dependencies for test module]
  Link: http://lkml.kernel.org/r/20170630154834.3689272-1-arnd@arndb.de
Link: http://lkml.kernel.org/r/20170628223155.26472-3-mcgrof@kernel.orgSigned-off-by: NLuis R. Rodriguez <mcgrof@kernel.org>
Cc: Jessica Yu <jeyu@redhat.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Michal Marek <mmarek@suse.com>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

As suggested by Jessica, I've been actively working on kmod, so might as
well reflect its maintained status.

Changes are expected to go through akpm's tree.

Link: http://lkml.kernel.org/r/20170628223155.26472-2-mcgrof@kernel.orgSigned-off-by: NLuis R. Rodriguez <mcgrof@kernel.org>
Suggested-by: NJessica Yu <jeyu@redhat.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Michal Marek <mmarek@suse.com>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The arch uses a verbatim copy of the asm-generic version and does not
add any own implementations to the header, so use asm-generic/fb.h
instead of duplicating code.

Link: http://lkml.kernel.org/r/20170517083545.2115-1-tklauser@distanz.chSigned-off-by: NTobias Klauser <tklauser@distanz.ch>
Acked-by: NMax Filippov <jcmvbkbc@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

fail-nth interface is only created in /proc/self/task/<current-tid>/.
This change also adds it in /proc/<pid>/.

This makes shell based tool a bit simpler.

	$ bash -c "builtin echo 100 > /proc/self/fail-nth && exec ls /"

Link: http://lkml.kernel.org/r/1491490561-10485-6-git-send-email-akinobu.mita@gmail.comSigned-off-by: NAkinobu Mita <akinobu.mita@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The fail-nth file is created with 0666 and the access is permitted if
and only if the task is current.

This file is owned by the currnet user.  So we can create it with 0644
and allow the owner to write it.  This enables to watch the status of
task->fail_nth from another processes.

[akinobu.mita@gmail.com: don't convert unsigned type value as signed int]
  Link: http://lkml.kernel.org/r/1492444483-9239-1-git-send-email-akinobu.mita@gmail.com
[akinobu.mita@gmail.com: avoid unwanted data race to task->fail_nth]
  Link: http://lkml.kernel.org/r/1499962492-8931-1-git-send-email-akinobu.mita@gmail.com
Link: http://lkml.kernel.org/r/1491490561-10485-5-git-send-email-akinobu.mita@gmail.comSigned-off-by: NAkinobu Mita <akinobu.mita@gmail.com>
Acked-by: NDmitry Vyukov <dvyukov@google.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The read interface for fail-nth looks a bit odd.  Read from this file
returns "NYYYY..." or "YYYYY..." (this makes me surprise when cat this
file).  Because there is no EOF condition.  The first character
indicates current->fail_nth is zero or not, and then current->fail_nth
is reset to zero.

Just returning task->fail_nth value is more natural to understand.

Link: http://lkml.kernel.org/r/1491490561-10485-4-git-send-email-akinobu.mita@gmail.comSigned-off-by: NAkinobu Mita <akinobu.mita@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The value written to fail-nth file is parsed as 0-based.  Parsing as
one-based is more natural to understand and it enables to cancel the
previous setup by simply writing '0'.

This change also converts task->fail_nth from signed to unsigned int.

Link: http://lkml.kernel.org/r/1491490561-10485-3-git-send-email-akinobu.mita@gmail.comSigned-off-by: NAkinobu Mita <akinobu.mita@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Automatically detect the number base to use when writing to fail-nth
file instead of always parsing as a decimal number.

Link: http://lkml.kernel.org/r/1491490561-10485-2-git-send-email-akinobu.mita@gmail.comSigned-off-by: NAkinobu Mita <akinobu.mita@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

After commit 73ce0511 ("kernel/watchdog.c: move hardlockup
detector to separate file"), 'NMI watchdog' is inappropriate in
kernel/watchdog.c, using 'watchdog' only.

Link: http://lkml.kernel.org/r/1499928642-48983-1-git-send-email-wangkefeng.wang@huawei.comSigned-off-by: NKefeng Wang <wangkefeng.wang@huawei.com>
Cc: Babu Moger <babu.moger@oracle.com>
Cc: Ingo Molnar <mingo@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Update the location of the befs git tree and my email address.

Link: http://lkml.kernel.org/r/20170709110012.2991-1-luisbg@kernel.orgSigned-off-by: NLuis de Bethencourt <luisbg@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

atomic64_inc_not_zero() returns a "truth value" which in C is
traditionally an int.  That means callers are likely to expect the
result will fit in an int.

If an implementation returns a "true" value which does not fit in an
int, then there's a possibility that callers will truncate it when they
store it in an int.

In fact this happened in practice, see commit 966d2b04
("percpu-refcount: fix reference leak during percpu-atomic transition").

So add a test that the result fits in an int, even when the input
doesn't.  This catches the case where an implementation just passes the
non-zero input value out as the result.

Link: http://lkml.kernel.org/r/1499775133-1231-1-git-send-email-mpe@ellerman.id.auSigned-off-by: NMichael Ellerman <mpe@ellerman.id.au>
Cc: Douglas Miller <dougmill@linux.vnet.ibm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Jörn Engel noticed that the expand_upwards() function might not return
-ENOMEM in case the requested address is (unsigned long)-PAGE_SIZE and
if the architecture didn't defined TASK_SIZE as multiple of PAGE_SIZE.

Affected architectures are arm, frv, m68k, blackfin, h8300 and xtensa
which all define TASK_SIZE as 0xffffffff, but since none of those have
an upwards-growing stack we currently have no actual issue.

Nevertheless let's fix this just in case any of the architectures with
an upward-growing stack (currently parisc, metag and partly ia64) define
TASK_SIZE similar.

Link: http://lkml.kernel.org/r/20170702192452.GA11868@p100.box
Fixes: bd726c90 ("Allow stack to grow up to address space limit")
Signed-off-by: NHelge Deller <deller@gmx.de>
Reported-by: NJörn Engel <joern@purestorage.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Pull NFS client updates from Anna Schumaker:
 "Stable bugfixes:
   - Fix -EACCESS on commit to DS handling
   - Fix initialization of nfs_page_array->npages
   - Only invalidate dentries that are actually invalid

  Features:
   - Enable NFSoRDMA transparent state migration
   - Add support for lookup-by-filehandle
   - Add support for nfs re-exporting

  Other bugfixes and cleanups:
   - Christoph cleaned up the way we declare NFS operations
   - Clean up various internal structures
   - Various cleanups to commits
   - Various improvements to error handling
   - Set the dt_type of . and .. entries in NFS v4
   - Make slot allocation more reliable
   - Fix fscache stat printing
   - Fix uninitialized variable warnings
   - Fix potential list overrun in nfs_atomic_open()
   - Fix a race in NFSoRDMA RPC reply handler
   - Fix return size for nfs42_proc_copy()
   - Fix against MAC forgery timing attacks"

* tag 'nfs-for-4.13-1' of git://git.linux-nfs.org/projects/anna/linux-nfs: (68 commits)
  NFS: Don't run wake_up_bit() when nobody is waiting...
  nfs: add export operations
  nfs4: add NFSv4 LOOKUPP handlers
  nfs: add a nfs_ilookup helper
  nfs: replace d_add with d_splice_alias in atomic_open
  sunrpc: use constant time memory comparison for mac
  NFSv4.2 fix size storage for nfs42_proc_copy
  xprtrdma: Fix documenting comments in frwr_ops.c
  xprtrdma: Replace PAGE_MASK with offset_in_page()
  xprtrdma: FMR does not need list_del_init()
  xprtrdma: Demote "connect" log messages
  NFSv4.1: Use seqid returned by EXCHANGE_ID after state migration
  NFSv4.1: Handle EXCHGID4_FLAG_CONFIRMED_R during NFSv4.1 migration
  xprtrdma: Don't defer MR recovery if ro_map fails
  xprtrdma: Fix FRWR invalidation error recovery
  xprtrdma: Fix client lock-up after application signal fires
  xprtrdma: Rename rpcrdma_req::rl_free
  xprtrdma: Pass only the list of registered MRs to ro_unmap_sync
  xprtrdma: Pre-mark remotely invalidated MRs
  xprtrdma: On invalidation failure, remove MWs from rl_registered
  ...

Pull SCSI target updates from Nicholas Bellinger:
 "It's been usually busy for summer, with most of the efforts centered
  around TCMU developments and various target-core + fabric driver bug
  fixing activities. Not particularly large in terms of LoC, but lots of
  smaller patches from many different folks.

  The highlights include:

   - ibmvscsis logical partition manager support (Michael Cyr + Bryant
     Ly)

   - Convert target/iblock WRITE_SAME to blkdev_issue_zeroout (hch +
     nab)

   - Add support for TMR percpu LUN reference counting (nab)

   - Fix a potential deadlock between EXTENDED_COPY and iscsi shutdown
     (Bart)

   - Fix COMPARE_AND_WRITE caw_sem leak during se_cmd quiesce (Jiang Yi)

   - Fix TMCU module removal (Xiubo Li)

   - Fix iser-target OOPs during login failure (Andrea Righi + Sagi)

   - Breakup target-core free_device backend driver callback (mnc)

   - Perform TCMU add/delete/reconfig synchronously (mnc)

   - Fix TCMU multiple UIO open/close sequences (mnc)

   - Fix TCMU CHECK_CONDITION sense handling (mnc)

   - Fix target-core SAM_STAT_BUSY + TASK_SET_FULL handling (mnc + nab)

   - Introduce TYPE_ZBC support in PSCSI (Damien Le Moal)

   - Fix possible TCMU memory leak + OOPs when recalculating cmd base
     size (Xiubo Li + Bryant Ly + Damien Le Moal + mnc)

   - Add login_keys_workaround attribute for non RFC initiators (Robert
     LeBlanc + Arun Easi + nab)"

* 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/nab/target-pending: (68 commits)
  iscsi-target: Add login_keys_workaround attribute for non RFC initiators
  Revert "qla2xxx: Fix incorrect tcm_qla2xxx_free_cmd use during TMR ABORT"
  tcmu: clean up the code and with one small fix
  tcmu: Fix possbile memory leak / OOPs when recalculating cmd base size
  target: export lio pgr/alua support as device attr
  target: Fix return sense reason in target_scsi3_emulate_pr_out
  target: Fix cmd size for PR-OUT in passthrough_parse_cdb
  tcmu: Fix dev_config_store
  target: pscsi: Introduce TYPE_ZBC support
  target: Use macro for WRITE_VERIFY_32 operation codes
  target: fix SAM_STAT_BUSY/TASK_SET_FULL handling
  target: remove transport_complete
  pscsi: finish cmd processing from pscsi_req_done
  tcmu: fix sense handling during completion
  target: add helper to copy sense to se_cmd buffer
  target: do not require a transport_complete for SCF_TRANSPORT_TASK_SENSE
  target: make device_mutex and device_list static
  tcmu: Fix flushing cmd entry dcache page
  tcmu: fix multiple uio open/close sequences
  tcmu: drop configured check in destroy
  ...

"perf lock" shows fairly heavy contention for the bit waitqueue locks
when doing an I/O heavy workload.
Use a bit to tell whether or not there has been contention for a lock
so that we can optimise away the bit waitqueue options in those cases.
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: NAnna Schumaker <Anna.Schumaker@Netapp.com>

This support for opening files on NFS by file handle, both through the
open_by_handle syscall, and for re-exporting NFS (for example using a
different version).  The support is very basic for now, as each open by
handle will have to do an NFSv4 open operation on the wire.  In the
future this will hopefully be mitigated by an open file cache, as well
as various optimizations in NFS for this specific case.
Signed-off-by: NPeng Tao <tao.peng@primarydata.com>
[hch: incorporated various changes, resplit the patches, new changelog]
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NAnna Schumaker <Anna.Schumaker@Netapp.com>

Pull nfsd updates from Bruce Fields:
 "Chuck's RDMA update overhauls the "call receive" side of the
  RPC-over-RDMA transport to use the new rdma_rw API.

  Christoph cleaned the way nfs operations are declared, removing a
  bunch of function-pointer casts and declaring the operation vectors as
  const.

  Christoph's changes touch both client and server, and both client and
  server pulls this time around should be based on the same commits from
  Christoph"

* tag 'nfsd-4.13' of git://linux-nfs.org/~bfields/linux: (53 commits)
  svcrdma: fix an incorrect check on -E2BIG and -EINVAL
  nfsd4: factor ctime into change attribute
  svcrdma: Remove svc_rdma_chunk_ctxt::cc_dir field
  svcrdma: use offset_in_page() macro
  svcrdma: Clean up after converting svc_rdma_recvfrom to rdma_rw API
  svcrdma: Clean-up svc_rdma_unmap_dma
  svcrdma: Remove frmr cache
  svcrdma: Remove unused Read completion handlers
  svcrdma: Properly compute .len and .buflen for received RPC Calls
  svcrdma: Use generic RDMA R/W API in RPC Call path
  svcrdma: Add recvfrom helpers to svc_rdma_rw.c
  sunrpc: Allocate up to RPCSVC_MAXPAGES per svc_rqst
  svcrdma: Don't account for Receive queue "starvation"
  svcrdma: Improve Reply chunk sanity checking
  svcrdma: Improve Write chunk sanity checking
  svcrdma: Improve Read chunk sanity checking
  svcrdma: Remove svc_rdma_marshal.c
  svcrdma: Avoid Send Queue overflow
  svcrdma: Squelch disconnection messages
  sunrpc: Disable splice for krb5i
  ...

Pull ext2, udf, reiserfs fixes from Jan Kara:
 "Several ext2, udf, and reiserfs fixes"

* 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs:
  ext2: Fix memory leak when truncate races ext2_get_blocks
  reiserfs: fix race in prealloc discard
  reiserfs: don't preallocate blocks for extended attributes
  udf: Convert udf_disk_stamp_to_time() to use mktime64()
  udf: Use time64_to_tm for timestamp conversion
  udf: Fix deadlock between writeback and udf_setsize()
  udf: Use i_size_read() in udf_adinicb_writepage()
  udf: Fix races with i_size changes during readpage
  udf: Remove unused UDF_DEFAULT_BLOCKSIZE

Pull documentation fixes from Jonathan Corbet:
 "A set of fixes for various warnings, including the one caused by the
  removal of kernel/rcu/srcu.c. Also correct a stray pointer in
  memory-barriers.txt"

* tag '4.13-fixes' of git://git.lwn.net/linux:
  kokr/memory-barriers.txt: Fix obsolete link to atomic_ops.txt
  memory-barriers.txt: Fix broken link to atomic_ops.txt
  docs: Turn off section numbering for the input docs
  docs: Include uaccess docs from the right file
  docs: Do not include from kernel/rcu/srcu.c

Pull more Kbuild updates from Masahiro Yamada:

 - Move generic-y of exported headers to uapi/asm/Kbuild for complete
   de-coupling of UAPI

 - Clean up scripts/Makefile.headersinst

 - Fix host programs for 32 bit machine with XFS file system

* tag 'kbuild-v4.13-2' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (29 commits)
  kbuild: Enable Large File Support for hostprogs
  kbuild: remove wrapper files handling from Makefile.headersinst
  kbuild: split exported generic header creation into uapi-asm-generic
  kbuild: do not include old-kbuild-file from Makefile.headersinst
  xtensa: move generic-y of exported headers to uapi/asm/Kbuild
  unicore32: move generic-y of exported headers to uapi/asm/Kbuild
  tile: move generic-y of exported headers to uapi/asm/Kbuild
  sparc: move generic-y of exported headers to uapi/asm/Kbuild
  sh: move generic-y of exported headers to uapi/asm/Kbuild
  parisc: move generic-y of exported headers to uapi/asm/Kbuild
  openrisc: move generic-y of exported headers to uapi/asm/Kbuild
  nios2: move generic-y of exported headers to uapi/asm/Kbuild
  nios2: remove unneeded arch/nios2/include/(generated/)asm/signal.h
  microblaze: move generic-y of exported headers to uapi/asm/Kbuild
  metag: move generic-y of exported headers to uapi/asm/Kbuild
  m68k: move generic-y of exported headers to uapi/asm/Kbuild
  m32r: move generic-y of exported headers to uapi/asm/Kbuild
  ia64: remove redundant generic-y += kvm_para.h from asm/Kbuild
  hexagon: move generic-y of exported headers to uapi/asm/Kbuild
  h8300: move generic-y of exported headers to uapi/asm/Kbuild
  ...

Pull more tracing updates from Steven Rostedt:
 "A few more minor updates:

   - Show the tgid mappings for user space trace tools to use

   - Fix and optimize the comm and tgid cache recording

   - Sanitize derived kprobe names

   - Ftrace selftest updates

   - trace file header fix

   - Update of Documentation/trace/ftrace.txt

   - Compiler warning fixes

   - Fix possible uninitialized variable"

* tag 'trace-v4.13-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
  ftrace: Fix uninitialized variable in match_records()
  ftrace: Remove an unneeded NULL check
  ftrace: Hide cached module code for !CONFIG_MODULES
  tracing: Do note expose stack_trace_filter without DYNAMIC_FTRACE
  tracing: Update Documentation/trace/ftrace.txt
  tracing: Fixup trace file header alignment
  selftests/ftrace: Add a testcase for kprobe event naming
  selftests/ftrace: Add a test to probe module functions
  selftests/ftrace: Update multiple kprobes test for powerpc
  trace/kprobes: Sanitize derived event names
  tracing: Attempt to record other information even if some fail
  tracing: Treat recording tgid for idle task as a success
  tracing: Treat recording comm for idle task as a success
  tracing: Add saved_tgids file to show cached pid to tgid mappings

This will be needed in order to implement the get_parent export op
for nfsd.
Signed-off-by: NJeff Layton <jeff.layton@primarydata.com>
Signed-off-by: NAnna Schumaker <Anna.Schumaker@Netapp.com>

This helper will allow to find an existing NFS inode by the file handle
and fattr.
Signed-off-by: NPeng Tao <tao.peng@primarydata.com>
[hch: split from a larger patch]
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NAnna Schumaker <Anna.Schumaker@Netapp.com>

It's a trival change but follows knfsd export document that asks
for d_splice_alias during lookup.
Signed-off-by: NPeng Tao <tao.peng@primarydata.com>
Signed-off-by: NAnna Schumaker <Anna.Schumaker@Netapp.com>

Otherwise, we enable a MAC forgery via timing attack.
Signed-off-by: NJason A. Donenfeld <Jason@zx2c4.com>
Cc: "J. Bruce Fields" <bfields@fieldses.org>
Cc: Jeff Layton <jlayton@poochiereds.net>
Cc: Trond Myklebust <trond.myklebust@primarydata.com>
Cc: Anna Schumaker <anna.schumaker@netapp.com>
Cc: linux-nfs@vger.kernel.org
Cc: stable@vger.kernel.org
Signed-off-by: NAnna Schumaker <Anna.Schumaker@Netapp.com>

Return size of COPY is u64 but it was assigned to an "int" status.
Signed-off-by: NOlga Kornievskaia <kolga@netapp.com>
Signed-off-by: NAnna Schumaker <Anna.Schumaker@Netapp.com>

Clean up.

FASTREG and LOCAL_INV WRs are typically not signaled. localinv_wake
is used for the last LOCAL_INV WR in a chain, which is always
signaled. The documenting comments should reflect that.
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Signed-off-by: NAnna Schumaker <Anna.Schumaker@Netapp.com>

Clean up.

Reported by: Geliang Tang <geliangtang@gmail.com>
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Signed-off-by: NAnna Schumaker <Anna.Schumaker@Netapp.com>

Clean up.

Commit 38f1932e ("xprtrdma: Remove FMRs from the unmap list
after unmapping") utilized list_del_init() to try to prevent some
list corruption. The corruption was actually caused by the reply
handler racing with a signal. Now that MR invalidation is properly
serialized, list_del_init() can safely be replaced.
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Signed-off-by: NAnna Schumaker <Anna.Schumaker@Netapp.com>

Some have complained about the log messages generated when xprtrdma
opens or closes a connection to a server. When an NFS mount is
mostly idle these can appear every few minutes as the client idles
out the connection and reconnects.

Connection and disconnection is a normal part of operation, and not
exceptional, so change these to dprintk's for now. At some point
all of these will be converted to tracepoints, but that's for
another day.
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Signed-off-by: NAnna Schumaker <Anna.Schumaker@Netapp.com>

Transparent State Migration copies a client's lease state from the
server where a filesystem used to reside to the server where it now
resides. When an NFSv4.1 client first contacts that destination
server, it uses EXCHANGE_ID to detect trunking relationships.

The lease that was copied there is returned to that client, but the
destination server sets EXCHGID4_FLAG_CONFIRMED_R when replying to
the client. This is because the lease was confirmed on the source
server (before it was copied).

When CONFIRMED_R is set, the client throws away the sequence ID
returned by the server. During a Transparent State Migration, however
there's no other way for the client to know what sequence ID to use
with a lease that's been migrated.

Therefore, the client must save and use the contrived slot sequence
value returned by the destination server even when CONFIRMED_R is
set.

Note that some servers always return a seqid of 1 after a migration.
Reported-by: NXuan Qi <xuan.qi@oracle.com>
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Tested-by: NXuan Qi <xuan.qi@oracle.com>
Signed-off-by: NAnna Schumaker <Anna.Schumaker@Netapp.com>

Transparent State Migration copies a client's lease state from the
server where a filesystem used to reside to the server where it now
resides. When an NFSv4.1 client first contacts that destination
server, it uses EXCHANGE_ID to detect trunking relationships.

The lease that was copied there is returned to that client, but the
destination server sets EXCHGID4_FLAG_CONFIRMED_R when replying to
the client. This is because the lease was confirmed on the source
server (before it was copied).

Normally, when CONFIRMED_R is set, a client purges the lease and
creates a new one. However, that throws away the entire benefit of
Transparent State Migration.

Therefore, the client must not purge that lease when it is possible
that Transparent State Migration has occurred.
Reported-by: NXuan Qi <xuan.qi@oracle.com>
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Tested-by: NXuan Qi <xuan.qi@oracle.com>
Signed-off-by: NAnna Schumaker <Anna.Schumaker@Netapp.com>

Deferred MR recovery does a DMA-unmapping of the MW. However, ro_map
invokes rpcrdma_defer_mr_recovery in some error cases where the MW
has not even been DMA-mapped yet.

Avoid a DMA-unmapping error replacing rpcrdma_defer_mr_recovery.

Also note that if ib_dma_map_sg is asked to map 0 nents, it will
return 0. So the extra "if (i == 0)" check is no longer needed.

Fixes: 42fe28f6 ("xprtrdma: Do not leak an MW during a DMA ...")
Fixes: 505bbe64 ("xprtrdma: Refactor MR recovery work queues")
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Signed-off-by: NAnna Schumaker <Anna.Schumaker@Netapp.com>

When ib_post_send() fails, all LOCAL_INV WRs past @bad_wr have to be
examined, and the MRs reset by hand.

I'm not sure how the existing code can work by comparing R_keys.
Restructure the logic so that instead it walks the chain of WRs,
starting from the first bad one.

Make sure to wait for completion if at least one WR was actually
posted. Otherwise, if the ib_post_send fails, we can end up
DMA-unmapping the MR while LOCAL_INV operations are in flight.

Commit 7a89f9c6 ("xprtrdma: Honor ->send_request API contract")
added the rdma_disconnect() call site. The disconnect actually
causes more problems than it solves, and SQ overruns happen only as
a result of software bugs. So remove it.

Fixes: d7a21c1b ("xprtrdma: Reset MRs in frwr_op_unmap_sync()")
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Signed-off-by: NAnna Schumaker <Anna.Schumaker@Netapp.com>

After a signal, the RPC client aborts synchronous RPCs running on
behalf of the signaled application.

The server is still executing those RPCs, and will write the results
back into the client's memory when it's done. By the time the server
writes the results, that memory is likely being used for other
purposes. Therefore xprtrdma has to immediately invalidate all
memory regions used by those aborted RPCs to prevent the server's
writes from clobbering that re-used memory.

With FMR memory registration, invalidation takes a relatively long
time. In fact, the invalidation is often still running when the
server tries to write the results into the memory regions that are
being invalidated.

This sets up a race between two processes:

1.  After the signal, xprt_rdma_free calls ro_unmap_safe.
2.  While ro_unmap_safe is still running, the server replies and
    rpcrdma_reply_handler runs, calling ro_unmap_sync.

Both processes invoke ib_unmap_fmr on the same FMR.

The mlx4 driver allows two ib_unmap_fmr calls on the same FMR at
the same time, but HCAs generally don't tolerate this. Sometimes
this can result in a system crash.

If the HCA happens to survive, rpcrdma_reply_handler continues. It
removes the rpc_rqst from rq_list and releases the transport_lock.
This enables xprt_rdma_free to run in another process, and the
rpc_rqst is released while rpcrdma_reply_handler is still waiting
for the ib_unmap_fmr call to finish.

But further down in rpcrdma_reply_handler, the transport_lock is
taken again, and "rqst" is dereferenced. If "rqst" has already been
released, this triggers a general protection fault. Since bottom-
halves are disabled, the system locks up.

Address both issues by reversing the order of the xprt_lookup_rqst
call and the ro_unmap_sync call. Introduce a separate lookup
mechanism for rpcrdma_req's to enable calling ro_unmap_sync before
xprt_lookup_rqst. Now the handler takes the transport_lock once
and holds it for the XID lookup and RPC completion.

BugLink: https://bugzilla.linux-nfs.org/show_bug.cgi?id=305
Fixes: 68791649 ('xprtrdma: Invalidate in the RPC reply ... ')
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Signed-off-by: NAnna Schumaker <Anna.Schumaker@Netapp.com>

Clean up: I'm about to use the rl_free field for purposes other than
a free list. So use a more generic name.

This is a refactoring change only.

BugLink: https://bugzilla.linux-nfs.org/show_bug.cgi?id=305
Fixes: 68791649 ('xprtrdma: Invalidate in the RPC reply ... ')
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Signed-off-by: NAnna Schumaker <Anna.Schumaker@Netapp.com>

There are rare cases where an rpcrdma_req can be re-used (via
rpcrdma_buffer_put) while the RPC reply handler is still running.
This is due to a signal firing at just the wrong instant.

Since commit 9d6b0409 ("xprtrdma: Place registered MWs on a
per-req list"), rpcrdma_mws are self-contained; ie., they fully
describe an MR and scatterlist, and no part of that information is
stored in struct rpcrdma_req.

As part of closing the above race window, pass only the req's list
of registered MRs to ro_unmap_sync, rather than the rpcrdma_req
itself.

Some extra transport header sanity checking is removed. Since the
client depends on its own recollection of what memory had been
registered, there doesn't seem to be a way to abuse this change.

And, the check was not terribly effective. If the client had sent
Read chunks, the "list_empty" test is negative in both of the
removed cases, which are actually looking for Write or Reply
chunks.

BugLink: https://bugzilla.linux-nfs.org/show_bug.cgi?id=305
Fixes: 68791649 ('xprtrdma: Invalidate in the RPC reply ... ')
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Signed-off-by: NAnna Schumaker <Anna.Schumaker@Netapp.com>

There are rare cases where an rpcrdma_req and its matched
rpcrdma_rep can be re-used, via rpcrdma_buffer_put, while the RPC
reply handler is still using that req. This is typically due to a
signal firing at just the wrong instant.

As part of closing this race window, avoid using the wrong
rpcrdma_rep to detect remotely invalidated MRs. Mark MRs as
invalidated while we are sure the rep is still OK to use.

BugLink: https://bugzilla.linux-nfs.org/show_bug.cgi?id=305
Fixes: 68791649 ('xprtrdma: Invalidate in the RPC reply ... ')
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Signed-off-by: NAnna Schumaker <Anna.Schumaker@Netapp.com>

Callers assume the ro_unmap_sync and ro_unmap_safe methods empty
the list of registered MRs. Ensure that all paths through
fmr_op_unmap_sync() remove MWs from that list.

Fixes: 9d6b0409 ("xprtrdma: Place registered MWs on a ... ")
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Signed-off-by: NAnna Schumaker <Anna.Schumaker@Netapp.com>