This patch creates a helper for handling requests when null_blk is
memory backed in the null_handle_cmd(). Although the helper is very
simple right now, it makes the code flow consistent with the rest of
code in the null_handle_cmd() and provides a uniform code structure
for future code.
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NChaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

This patch creates a helper for handling badblocks code in the
null_handle_cmd().
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NChaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

This patch creates a helper for handling throttling code in the
null_handle_cmd().
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NChaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

This is a preparation patch which moves the duplicate code for sectors
and nr_sectors calculations for bio vs request mode into their
respective callers (null_queue_bio(), null_qeueue_req()). Now the core
function only deals with the respective actions and commands instead of
having to calculte the bio vs req operations and different sector
related variables. We also move the flush command handling at the top
which significantly simplifies the rest of the code.
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NChaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

Hiding page refcount manipulation inside a low-level bio helper is
somewhat awkward.  Instead return the same page information to the
callers, where it fits in much better.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

Passsthrough bio handling should be the same as normal bio handling,
except that we need to take hardware limitations into account.  Thus
use the common try_merge implementation after checking the hardware
limits.  This changes behavior in that we now also check segment
and dma boundary settings for same page merges, which is a little
more work but has no effect as those need to be larger than the
page size.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

If we can add more data into an existing segment we do not create a gap
per definition, so move the check for a gap after the attempt to merge
into the segment.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NJohannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

This fixes a bug added in 4.10 with commit:

commit 9561a7ad
Author: Josef Bacik <jbacik@fb.com>
Date:   Tue Nov 22 14:04:40 2016 -0500

    nbd: add multi-connection support

that limited the number of devices to 256. Before the patch we could
create 1000s of devices, but the patch switched us from using our
own thread to using a work queue which has a default limit of 256
active works.

The problem is that our recv_work function sits in a loop until
disconnection but only handles IO for one connection. The work is
started when the connection is started/restarted, but if we end up
creating 257 or more connections, the queue_work call just queues
connection257+'s recv_work and that waits for connection 1 - 256's
recv_work to be disconnected and that work instance completing.

Instead of reverting back to kthreads, this has us allocate a
workqueue_struct per device, so we can block in the work.

Cc: stable@vger.kernel.org
Reviewed-by: NJosef Bacik <josef@toxicpanda.com>
Signed-off-by: NMike Christie <mchristi@redhat.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

This fixes a regression added in 4.9 with commit:

commit 0eadf37a
Author: Josef Bacik <jbacik@fb.com>
Date:   Thu Sep 8 12:33:40 2016 -0700

    nbd: allow block mq to deal with timeouts

where before the patch userspace would set the timeout to 0 to disable
it. With the above patch, a zero timeout tells the block layer to use
the default value of 30 seconds. For setups where commands can take a
long time or experience transient issues like network disruptions this
then results in IO errors being sent to the application.

To fix this, the patch still uses the common block layer timeout
framework, but if zero is set, nbd just logs a message and then resets
the timer when it expires.
Reviewed-by: NJosef Bacik <josef@toxicpanda.com>
Signed-off-by: NMike Christie <mchristi@redhat.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

Fix bug added with the patch:

commit 8f3ea359
Author: Josef Bacik <josef@toxicpanda.com>
Date:   Mon Jul 16 12:11:35 2018 -0400

    nbd: handle unexpected replies better

where if the timeout handler runs when the completion path is and we fail
to grab the mutex in the timeout handler we will leave a config reference
and cannot free the config later.
Reviewed-by: NJosef Bacik <josef@toxicpanda.com>
Signed-off-by: NMike Christie <mchristi@redhat.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

This adds a helper function to convert a block req op to a nbd cmd type.
It will be used in the last patch to log the type in the timeout
handler.
Reviewed-by: NJosef Bacik <josef@toxicpanda.com>
Signed-off-by: NMike Christie <mchristi@redhat.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

Add a helper to set the cmd timeout. It does not really do a lot now,
but will be more useful in the next patches.
Reviewed-by: NJosef Bacik <josef@toxicpanda.com>
Signed-off-by: NMike Christie <mchristi@redhat.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

The original commit adding the sed-opal library by mistake added two
definitions of OPAL_METHOD_LENGTH, remove one of them.
Signed-off-by: NRevanth Rajashekar <revanth.rajashekar@intel.com>
Reviewed-by: NScott Bauer <sbauer@plzdonthack.me>
Reviewed-by: NJon Derrick <jonathan.derrick@intel.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

In the function 'response_parse', num_entries will never be 0 as
slen is checked for 0. Hence, the condition 'if (num_entries == 0)'
can never be true.
Signed-off-by: NRevanth Rajashekar <revanth.rajashekar@intel.com>
Reviewed-by: NScott Bauer <sbauer@plzdonthack.me>
Reviewed-by: NJon Derrick <jonathan.derrick@intel.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

Signed-off-by: NRevanth Rajashekar <revanth.rajashekar@intel.com>
Reviewed-by: NScott Bauer <sbauer@plzdonthack.me>
Reviewed-by: NJon Derrick <jonathan.derrick@intel.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

The dispatch list is not used any more, as the legacy block IO stack
has been removed.
Reviewed-by: NBart Van Assche <bvanassche@acm.org>
Reviewed-by: NMing Lei <ming.lei@redhat.com>
Signed-off-by: NJunxiao Bi <junxiao.bi@oracle.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

As inode wb switching may make sync(2) miss some inodes, they're
synchronized using wb_switch_rwsem so that no wb switching happens
while sync(2) is in progress.  In addition to synchronizing the actual
switching, the rwsem is also used to prevent queueing new switch
attempts while sync(2) is in progress.  This is to avoid queueing too
many instances while the rwsem is held by sync(2).  Unfortunately,
this is too agressive and can block wb switching for a long time if
sync(2) is frequent.

The goal is avoiding expolding the number of scheduled switches, not
avoiding scheduling anything.  Let's use wb_switch_rwsem only for
synchronizing the actual switching and sync(2) and use
isw_nr_in_flight instead for limiting the maximum number of scheduled
switches.  The limit is set to 1024 which should be more than enough
while still avoiding extreme situations.
Reviewed-by: NJan Kara <jack@suse.cz>
Signed-off-by: NTejun Heo <tj@kernel.org>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

WB_FRN_TIME_CUT_DIV is used to tell the foreign inode detection logic
to ignore short writeback rounds to prevent getting confused by a
burst of short writebacks.  The parameter is currently 2 meaning that
anything smaller than half of the running average writback duration
will be ignored.

This is unnecessarily aggressive.  The detection logic uses 16 history
slots and is already reasonably protected against some short bursts
confusing it and the current parameter can lead to tens of seconds of
missed detection depending on the writeback pattern.

Let's change the parameter to 8, so that it only ignores writeback
with are smaller than 12.5% of the current running average.

v2: Add comment explaining what's going on with the foreign detection
    parameters.
Reviewed-by: NJan Kara <jack@suse.cz>
Signed-off-by: NTejun Heo <tj@kernel.org>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

psi tracks the time tasks wait for refaulting pages to become
uptodate, but it does not track the time spent submitting the IO. The
submission part can be significant if backing storage is contended or
when cgroup throttling (io.latency) is in effect - a lot of time is
spent in submit_bio(). In that case, we underreport memory pressure.

Annotate submit_bio() to account submission time as memory stall when
the bio is reading userspace workingset pages.
Tested-by: NSuren Baghdasaryan <surenb@google.com>
Signed-off-by: NJohannes Weiner <hannes@cmpxchg.org>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

If blk_mq_init_allocated_queue->elevator_init_mq fails, need to release
the previously requested resources.

Fixes: d3484991 ("blk-mq-sched: allow setting of default IO scheduler")
Signed-off-by: Nzhengbin <zhengbin13@huawei.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

As sparse points out, these two copy_from_user() should actually be
copy_to_user().

Fixes: 229b53c9 ("take floppy compat ioctls to sodding floppy.c")
Cc: stable@vger.kernel.org
Acked-by: NAlexander Popov <alex.popov@linux.com>
Reviewed-by: NMukesh Ojha <mojha@codeaurora.org>
Signed-off-by: NJann Horn <jannh@google.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

A previous commit correctly removed set-but-not-read variables, but
this left two new variables now unused. Kill them.

Fixes: ba6f7da9 ("lightnvm: remove set but not used variables 'data_len' and 'rq_len'")
Reported-by: NStephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

Enabling Direct I/O with loop devices helps reducing memory usage by
avoiding double caching.  32 bit applications running on 64 bits systems
are currently not able to request direct I/O because is missing from the
lo_compat_ioctl.

This patch fixes the compatibility issue mentioned above by exporting
LOOP_SET_DIRECT_IO as additional lo_compat_ioctl() entry.
The input argument for this ioctl is a single long converted to a 1-bit
boolean, so compatibility is preserved.

Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: NAlessio Balsini <balsini@android.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

In function sg_split, the second sg_calculate_split will return -EINVAL
when in_mapped_nents is 0.

Indeed there is no need to do second sg_calculate_split and sg_split_mapped
when in_mapped_nents is 0, as in_mapped_nents indicates no mapped entry in
original sgl.
Signed-off-by: NZhou Wang <wangzhou1@hisilicon.com>
Acked-by: NRobert Jarzmik <robert.jarzmik@free.fr>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

drivers/lightnvm/pblk-read.c: In function pblk_submit_read_gc:
drivers/lightnvm/pblk-read.c:423:6: warning: variable data_len set but not used [-Wunused-but-set-variable]
drivers/lightnvm/pblk-recovery.c: In function pblk_recov_scan_oob:
drivers/lightnvm/pblk-recovery.c:368:15: warning: variable rq_len set but not used [-Wunused-but-set-variable]

They are not used since commit 48e5da72 ("lightnvm:
move metadata mapping to lower level driver")
Reported-by: NHulk Robot <hulkci@huawei.com>
Signed-off-by: NYueHaibing <yuehaibing@huawei.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

Pull MD changes from Song.

* 'md-next' of https://github.com/liu-song-6/linux:
  raid1: factor out a common routine to handle the completion of sync write
  md: don't call spare_active in md_reap_sync_thread if all member devices can't work
  md: don't set In_sync if array is frozen
  md: allow last device to be forcibly removed from RAID1/RAID10.
  md: Convert to use int_pow()
  md/raid10: end bio when the device faulty
  md/raid1: end bio when the device faulty
  md/raid6: Set R5_ReadError when there is read failure on parity disk
  raid1: use an int as the return value of raise_barrier()

It's just code clean-up.
Signed-off-by: NHou Tao <houtao1@huawei.com>
Signed-off-by: NSong Liu <songliubraving@fb.com>

When add one disk to array, the md_reap_sync_thread is responsible
to activate the spare and set In_sync flag for the new member in
spare_active().

But if raid1 has one member disk A, and disk B is added to the array.
Then we offline A before all the datas are synchronized from A to B,
obviously B doesn't have the latest data as A, but B is still marked
with In_sync flag.

So let's not call spare_active under the condition, otherwise B is
still showed with 'U' state which is not correct.
Signed-off-by: NGuoqing Jiang <guoqing.jiang@cloud.ionos.com>
Signed-off-by: NSong Liu <songliubraving@fb.com>

When a disk is added to array, the following path is called in mdadm.

Manage_subdevs -> sysfs_freeze_array
               -> Manage_add
               -> sysfs_set_str(&info, NULL, "sync_action","idle")

Then from kernel side, Manage_add invokes the path (add_new_disk ->
validate_super = super_1_validate) to set In_sync flag.

Since In_sync means "device is in_sync with rest of array", and the new
added disk need to resync thread to help the synchronization of data.
And md_reap_sync_thread would call spare_active to set In_sync for the
new added disk finally. So don't set In_sync if array is in frozen.
Signed-off-by: NGuoqing Jiang <guoqing.jiang@cloud.ionos.com>
Signed-off-by: NSong Liu <songliubraving@fb.com>

When the 'last' device in a RAID1 or RAID10 reports an error,
we do not mark it as failed.  This would serve little purpose
as there is no risk of losing data beyond that which is obviously
lost (as there is with RAID5), and there could be other sectors
on the device which are readable, and only readable from this device.
This in general this maximises access to data.

However the current implementation also stops an admin from removing
the last device by direct action.  This is rarely useful, but in many
case is not harmful and can make automation easier by removing special
cases.

Also, if an attempt to write metadata fails the device must be marked
as faulty, else an infinite loop will result, attempting to update
the metadata on all non-faulty devices.

So add 'fail_last_dev' member to 'struct mddev', then we can bypasses
the 'last disk' checks for RAID1 and RAID10, and control the behavior
per array by change sysfs node.
Signed-off-by: NNeilBrown <neilb@suse.de>
[add sysfs node for fail_last_dev by Guoqing]
Signed-off-by: NGuoqing Jiang <guoqing.jiang@cloud.ionos.com>
Signed-off-by: NSong Liu <songliubraving@fb.com>

Instead of linear approach to calculate power of 10, use generic int_pow()
which does it better.
Signed-off-by: NAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: NSong Liu <songliubraving@fb.com>

Just like raid1, we do not queue write error bio to retry write
and acknowlege badblocks, when the device is faulty.
Signed-off-by: NYufen Yu <yuyufen@huawei.com>
Signed-off-by: NSong Liu <songliubraving@fb.com>

When write bio return error, it would be added to conf->retry_list
and wait for raid1d thread to retry write and acknowledge badblocks.

In narrow_write_error(), the error bio will be split in the unit of
badblock shift (such as one sector) and raid1d thread issues them
one by one. Until all of the splited bio has finished, raid1d thread
can go on processing other things, which is time consuming.

But, there is a scene for error handling that is not necessary.
When the device has been set faulty, flush_bio_list() may end
bios in pending_bio_list with error status. Since these bios
has not been issued to the device actually, error handlding to
retry write and acknowledge badblocks make no sense.

Even without that scene, when the device is faulty, badblocks info
can not be written out to the device. Thus, we also no need to
handle the error IO.
Signed-off-by: NYufen Yu <yuyufen@huawei.com>
Signed-off-by: NSong Liu <songliubraving@fb.com>

7471fb77 ("md/raid6: Fix anomily when recovering a single device in
RAID6.") avoids rereading P when it can be computed from other members.
However, this misses the chance to re-write the right data to P. This
patch sets R5_ReadError if the re-read fails.

Also, when re-read is skipped, we also missed the chance to reset
rdev->read_errors to 0. It can fail the disk when there are many read
errors on P member disk (other disks don't have read error)

V2: upper layer read request don't read parity/Q data. So there is no
need to consider such situation.

This is Reported-by: kbuild test robot <lkp@intel.com>

Fixes: 7471fb77 ("md/raid6: Fix anomily when recovering a single device in RAID6.")
Cc: <stable@vger.kernel.org> #4.4+
Signed-off-by: NXiao Ni <xni@redhat.com>
Signed-off-by: NSong Liu <songliubraving@fb.com>

Using a sector_t as the return value is misleading, because
raise_barrier() only return 0 or -EINTR.

Also add comments for the return values of raise_barrier().
Signed-off-by: NHou Tao <houtao1@huawei.com>
Signed-off-by: NSong Liu <songliubraving@fb.com>

Now that there no module users left of bio_map_kern, stop exporting the
symbol.
Reviewed-by: NJavier González <javier@javigon.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NHans Holmberg <hans@owltronix.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

There is no reason now not to use kvmalloc, so replace the internal
metadata allocation scheme.
Reviewed-by: NJavier González <javier@javigon.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NHans Holmberg <hans@owltronix.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

Now that blk_rq_map_kern can map both kmem and vmem, move internal
metadata mapping down to the lower level driver.
Reviewed-by: NJavier González <javier@javigon.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NHans Holmberg <hans@owltronix.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

Move the redundant sync handling interface and wait for a completion in
the lightnvm core instead.
Reviewed-by: NJavier González <javier@javigon.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NHans Holmberg <hans@owltronix.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

Spread queues among present CPUs first, then building mapping on other
non-present CPUs.

So we can minimize count of dead queues which are mapped by un-present
CPUs only. Then bad IO performance can be avoided by unbalanced mapping
between present CPUs and queues.

The similar policy has been applied on Managed IRQ affinity.

Cc: Yi Zhang <yi.zhang@redhat.com>
Reported-by: NYi Zhang <yi.zhang@redhat.com>
Reviewed-by: NBob Liu <bob.liu@oracle.com>
Signed-off-by: NMing Lei <ming.lei@redhat.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>