conn_try_disconnect() could potentialy hit the BUG_ON()
in _conn_set_state() where it iterates over _drbd_set_state()
and "asserts" via BUG_ON() that the latter was successful.

If the STATE_SENT bit was not yet visible to conn_is_valid_transition()
early in _conn_request_state(), but became visible before conn_set_state()
later in that call path, we could hit the BUG_ON() after _drbd_set_state(),
because it returned SS_IN_TRANSIENT_STATE.

To avoid that race, we better protect set_bit(SENT_STATE) with the spinlock.
Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: NLars Ellenberg <lars.ellenberg@linbit.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

When requesting a detach, we first suspend IO, and also inhibit meta-data IO
by means of drbd_md_get_buffer(), because we don't want to "fail" the disk
while there is IO in-flight: the transition into D_FAILED for detach purposes
may get misinterpreted as actual IO error in a confused endio function.

We wrap it all into wait_event(), to retry in case the drbd_req_state()
returns SS_IN_TRANSIENT_STATE, as it does for example during an ongoing
connection handshake.

In that example, the receiver thread may need to grab drbd_md_get_buffer()
during the handshake to make progress.  To avoid potential deadlock with
detach, detach needs to grab and release the meta data buffer inside of
that wait_event retry loop. To avoid lock inversion between
mutex_lock(&device->state_mutex) and drbd_md_get_buffer(device),
introduce a new enum chg_state_flag CS_INHIBIT_MD_IO, and move the
call to drbd_md_get_buffer() inside the state_mutex grabbed in
drbd_req_state().
Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: NLars Ellenberg <lars.ellenberg@linbit.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

Thus use the corresponding function "seq_putc".

This issue was detected by using the Coccinelle software.
Signed-off-by: NMarkus Elfring <elfring@users.sourceforge.net>
Signed-off-by: NRoland Kammerer <roland.kammerer@linbit.com>
Signed-off-by: NLars Ellenberg <lars.ellenberg@linbit.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

If there are still resources defined, but "empty", no more volumes
or connections configured, they don't hold module reference counts,
so rmmod is possible.

To avoid DRBD leftovers in debugfs, we need to call our global
drbd_debugfs_cleanup() only after all resources have been cleaned up.
Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: NLars Ellenberg <lars.ellenberg@linbit.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

Signed-off-by: NGeliang Tang <geliangtang@gmail.com>
Signed-off-by: NRoland Kammerer <roland.kammerer@linbit.com>
Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

Race:

drbd_adm_attach()               | async drbd_md_endio()
                                |
device->ldev is still NULL.     |
                                |
drbd_md_read(                   |
 .endio = drbd_md_endio;        |
 submit;                        |
 ....                           |
 wait for done == 1;            |       done = 1;
);                              |       wake_up();
.. lot of other stuff,          |
.. includeing taking and        |
...giving up locks,             |
.. doing further IO,            |
.. stuff that takes "some time" |
                                | while in this context,
                                | this is the next statement.
                                | which means this context was scheduled
.. only then, finally,          | away for "some time".
device->ldev = nbc;             |
                                |       if (device->ldev)
                                |               put_ldev()

Unlikely, but possible. I was able to provoke it "reliably"
by adding an mdelay(500); after the wake_up().
Fixed by moving the if (!NULL) put_ldev() before done = 1;

Impact of the bug was that the resulting refcount imbalance
could lead to premature destruction of the object, potentially
causing a NULL pointer dereference during a subsequent detach.
Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: NLars Ellenberg <lars.ellenberg@linbit.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

Some backend devices claim to support write-same,
but would fail actual write-same requests.

Allow to set (or toggle) whether or not DRBD tries to support write-same.
Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: NLars Ellenberg <lars.ellenberg@linbit.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

The conn_higest_role() (a terribly misnamed function) returns
the role of the resource. It returned R_UNKNOWN as long as the
resource has not a single device.

Resources without devices are short living objects.

But it matters for the NOTIFY_CREATE netwlink message. It makes
a lot more sense to report R_SECONDARY for the newly created
resource than R_UNKNOWN.

I reviewd all call sites of conn_highest_role(), that change
does not matter for the other call sites.
Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: NLars Ellenberg <lars.ellenberg@linbit.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

We get a few warnings when building kernel with W=1:
drbd/drbd_receiver.c:1224:6: warning: no previous prototype for 'one_flush_endio' [-Wmissing-prototypes]
drbd/drbd_req.c:1450:6: warning: no previous prototype for 'send_and_submit_pending' [-Wmissing-prototypes]
drbd/drbd_main.c:924:6: warning: no previous prototype for 'assign_p_sizes_qlim' [-Wmissing-prototypes]
....

In fact, these functions are only used in the file in which they are
declared and don't need a declaration, but can be made static.
So this patch marks these functions with 'static'.
Signed-off-by: NBaoyou Xie <baoyou.xie@linaro.org>
Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: NLars Ellenberg <lars.ellenberg@linbit.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

In protocol != C, we forgot to send the P_NEG_ACK for failing writes.

Once we no longer submit to local disk, because we already "detached",
due to the typical "on-io-error detach;" config setting,
we already send the neg acks right away.

Only those requests that have been submitted,
and have been error-completed by the local disk,
would forget to send the neg-ack,
and only in asynchronous replication (protocol != C).
Unless this happened during resync,
where we already always send acks, regardless of protocol.

The primary side needs the P_NEG_ACK in order to mark
the affected block(s) for resync in its out-of-sync bitmap.

If the blocks in question are not re-written again,
we may miss to resync them later, causing data inconsistencies.

This patch will always send the neg-acks, and also at least try to
persist the out-of-sync status on the local node already.
Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: NLars Ellenberg <lars.ellenberg@linbit.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

When submitting batches of requests which had been queued on the
submitter thread, typically because they needed to wait for an
activity log transactions, use explicit plugging to help potential
merging of requests in the backend io-scheduler.
Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: NLars Ellenberg <lars.ellenberg@linbit.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

Two instances of list_for_each_safe can drop their tmp element, they
really just peel off each element in turn from the start of the list.
Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: NLars Ellenberg <lars.ellenberg@linbit.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

Recently, drbd_recv_header() was changed to potentially
implicitly "unplug" the backend device(s), in case there
is currently nothing to receive.

Be more explicit about it: re-introduce the original drbd_recv_header(),
and introduce a new drbd_recv_header_maybe_unplug() for use by the
receiver "main loop".

Using explicit plugging via blk_start_plug(); blk_finish_plug();
really helps the io-scheduler of the backend with merging requests.

Wrap the receiver "main loop" with such a plug.
Also catch unplug events on the Primary,
and try to propagate.

This is performance relevant.  Without this, if the receiving side does
not merge requests, number of IOPS on the peer can me significantly
higher than IOPS on the Primary, and can easily become the bottleneck.

Together, both changes should help to reduce the number of IOPS
as seen on the backend of the receiving side, by increasing
the chance of merging mergable requests, without trading latency
for more throughput.
Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: NLars Ellenberg <lars.ellenberg@linbit.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

The block core requests modules with the "-iosched" name suffix, but
mq-deadline does not have that suffix.  Add an alias.

Fixes: 945ffb60 ("mq-deadline: add blk-mq adaptation of the deadline ...")
Reviewed-by: NMing Lei <ming.lei@redhat.com>
Signed-off-by: NBen Hutchings <ben@decadent.org.uk>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

The block core requests modules with the "-iosched" name suffix, but
bfq no longer has that suffix.  Add an alias.

Fixes: ea25da48 ("block, bfq: split bfq-iosched.c into multiple ...")
Reviewed-by: NMing Lei <ming.lei@redhat.com>
Signed-off-by: NBen Hutchings <ben@decadent.org.uk>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

The only caller of this function is blk_start_request() in the same
file. Fix blk_start_request() description accordingly.
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NBart Van Assche <bart.vanassche@wdc.com>
Signed-off-by: NDamien Le Moal <damien.lemoal@wdc.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

Since blk_mq_init_queue() initializes .nr_requests to the tag set
size and since that value is a good default for the skd driver, do
not overwrite the value set by blk_mq_init_queue(). This change
doubles the default value of .nr_requests.
Signed-off-by: NBart Van Assche <bart.vanassche@wdc.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Hannes Reinecke <hare@suse.de>
Cc: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

Since sTec s1120 devices support 64-bit DMA it is not necessary
to request data buffer bouncing. Hence remove the
blk_queue_bounce_limit() call.
Suggested-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NBart Van Assche <bart.vanassche@wdc.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Hannes Reinecke <hare@suse.de>
Cc: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

Make this const as is is only passed as an argument to the
function device_create_file and device_remove_file and the corresponding
arguments are of type const.
Done using Coccinelle
Signed-off-by: NBhumika Goyal <bhumirks@gmail.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

We already have this pointer, no need to use to_nullb_device()
again.
Signed-off-by: NJens Axboe <axboe@kernel.dk>

Commit 2984c868(nullb: factor disk parameters) has a typo. The
nullb_device allocation/free is done outside of null_add_dev. The commit
accidentally frees the nullb_device in error code path.
Reported-by: NDan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: NShaohua Li <shli@fb.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

There is a race between changing I/O elevator and request_queue removal
which can trigger the warning in kobject_add_internal.  A program can
use sysfs to request a change of elevator at the same time another task
is unregistering the request_queue the elevator would be attached to.
The elevator's kobject will then attempt to be connected to the
request_queue in the object tree when the request_queue has just been
removed from sysfs.  This triggers the warning in kobject_add_internal
as the request_queue no longer has a sysfs directory:

kobject_add_internal failed for iosched (error: -2 parent: queue)
------------[ cut here ]------------
WARNING: CPU: 3 PID: 14075 at lib/kobject.c:244 kobject_add_internal+0x103/0x2d0

To fix this warning, we can check the QUEUE_FLAG_REGISTERED flag when
changing the elevator and use the request_queue's sysfs_lock to
serialize between clearing the flag and the elevator testing the flag.
Signed-off-by: NDavid Jeffery <djeffery@redhat.com>
Tested-by: NMing Lei <ming.lei@redhat.com>
Reviewed-by: NMing Lei <ming.lei@redhat.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

The last parameter "count" never be used in xxx_var_store,
convert these functions to void.
Signed-off-by: Nweiping zhang <zhangweiping@didichuxing.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

The SKD_ID_INCR flag in skd_request_context.id duplicates information
that is already available otherwise, e.g. through the block layer
request state and through skd_request_context.state. Hence remove
the code that manipulates this flag and also the flag itself.
Since skd_isr_completion_posted() only uses the lower bits of
skd_request_context.id as hardware tag, this patch does not change
the behavior of the skd driver. I'm referring to the following code:

    tag = req_id & SKD_ID_SLOT_AND_TABLE_MASK;
Signed-off-by: NBart Van Assche <bart.vanassche@wdc.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Hannes Reinecke <hare@suse.de>
Cc: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

Although it is easy to see that skdev->disk != NULL if skdev->queue
!= NULL, add a test for skdev->disk to avoid that smatch reports the
following warning:

drivers/block/skd_main.c:3080 skd_free_disk()
         error: we previously assumed 'disk' could be null (see line 3074)
Reported-by: NDan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: NBart Van Assche <bart.vanassche@wdc.com>
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Hannes Reinecke <hare@suse.de>
Cc: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

It is not worth to keep the debug statements in skd_end_request().
Without debug statements that function only consists of two
statements. Hence inline skd_end_request().
Suggested-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NBart Van Assche <bart.vanassche@wdc.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Hannes Reinecke <hare@suse.de>
Cc: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

The latter name follows more closely the function names used in
other blk-mq drivers.
Suggested-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NBart Van Assche <bart.vanassche@wdc.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Hannes Reinecke <hare@suse.de>
Cc: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

Dan reported this:

The patch 2984c868: "nullb: factor disk parameters" from Aug 14,
2017, leads to the following Smatch complaint:

drivers/block/null_blk.c:1759 null_init_tag_set()
	 error: we previously assumed 'nullb' could be null (see line
1750)

  1755		set->cmd_size	= sizeof(struct nullb_cmd);
  1756		set->flags = BLK_MQ_F_SHOULD_MERGE;
  1757		set->driver_data = NULL;
  1758
  1759		if (nullb->dev->blocking)
                    ^^^^^^^^^^^^^^^^^^^^
And an unchecked dereference.

nullb could be NULL here.
Reported-by: NDan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: NShaohua Li <shli@fb.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

this patch fix two errors, firstly avoid kfree blk_root, secondly not
free(blkcg) ,if blkcg alloc fail(blkcg == NULL), just unlock that mutex;
Signed-off-by: Nweiping zhang <zhangweiping@didichuxing.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

Update to a working one, the fusionio address hasn't been valid
in 4 years.
Signed-off-by: NJens Axboe <axboe@kernel.dk>

Normally I wouldn't bother with this, but in my opinion the comments are
the most important part of this whole file since without them no one
would have any clue how this insanity works.
Signed-off-by: NOmar Sandoval <osandov@fb.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

This patch avoids that sparse reports the following warning messages:

block/compat_ioctl.c:85:11: warning: incorrect type in assignment (different address spaces)
block/compat_ioctl.c:85:11:    expected unsigned long *[noderef] <asn:1>p
block/compat_ioctl.c:85:11:    got void [noderef] <asn:1>*
block/compat_ioctl.c:91:21: warning: incorrect type in argument 1 (different address spaces)
block/compat_ioctl.c:91:21:    expected void const volatile [noderef] <asn:1>*<noident>
block/compat_ioctl.c:91:21:    got unsigned long *[noderef] <asn:1>p
block/compat_ioctl.c:87:53: warning: dereference of noderef expression
block/compat_ioctl.c:91:21: warning: dereference of noderef expression

Fixes: commit d597580d ("generic ...copy_..._user primitives")
Signed-off-by: NBart Van Assche <bart.vanassche@wdc.com>
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

put_device(pdev) will call pdev->type->release finally, and blk_free_devt
has been called in part_release(), so remove it.
Signed-off-by: Nweiping zhang <zhangweiping@didichuxing.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

In dm-integrity target we register integrity profile that have
both generate_fn and verify_fn callbacks set to NULL.

This is used if dm-integrity is stacked under a dm-crypt device
for authenticated encryption (integrity payload contains authentication
tag and IV seed).

In this case the verification is done through own crypto API
processing inside dm-crypt; integrity profile is only holder
of these data. (And memory is owned by dm-crypt as well.)

After the commit (and previous changes)
  Commit 7c20f116
  Author: Christoph Hellwig <hch@lst.de>
  Date:   Mon Jul 3 16:58:43 2017 -0600

    bio-integrity: stop abusing bi_end_io

we get this crash:

: BUG: unable to handle kernel NULL pointer dereference at   (null)
: IP:   (null)
: *pde = 00000000
...
:
: Workqueue: kintegrityd bio_integrity_verify_fn
: task: f48ae180 task.stack: f4b5c000
: EIP:   (null)
: EFLAGS: 00210286 CPU: 0
: EAX: f4b5debc EBX: 00001000 ECX: 00000001 EDX: 00000000
: ESI: 00001000 EDI: ed25f000 EBP: f4b5dee8 ESP: f4b5dea4
:  DS: 007b ES: 007b FS: 00d8 GS: 00e0 SS: 0068
: CR0: 80050033 CR2: 00000000 CR3: 32823000 CR4: 001406d0
: Call Trace:
:  ? bio_integrity_process+0xe3/0x1e0
:  bio_integrity_verify_fn+0xea/0x150
:  process_one_work+0x1c7/0x5c0
:  worker_thread+0x39/0x380
:  kthread+0xd6/0x110
:  ? process_one_work+0x5c0/0x5c0
:  ? kthread_worker_fn+0x100/0x100
:  ? kthread_worker_fn+0x100/0x100
:  ret_from_fork+0x19/0x24
: Code:  Bad EIP value.
: EIP:   (null) SS:ESP: 0068:f4b5dea4
: CR2: 0000000000000000

Patch just skip the whole verify workqueue if verify_fn is set to NULL.

Fixes: 7c20f116 ("bio-integrity: stop abusing bi_end_io")
Signed-off-by: NMilan Broz <gmazyland@gmail.com>
[hch: trivial whitespace fix]
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

if elv_register fail, bfq_pool should be free.
Signed-off-by: Nweiping zhang <zhangweiping@didichuxing.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

This way we don't need a block_device structure to submit I/O.  The
block_device has different life time rules from the gendisk and
request_queue and is usually only available when the block device node
is open.  Other callers need to explicitly create one (e.g. the lightnvm
passthrough code, or the new nvme multipathing code).

For the actual I/O path all that we need is the gendisk, which exists
once per block device.  But given that the block layer also does
partition remapping we additionally need a partition index, which is
used for said remapping in generic_make_request.

Note that all the block drivers generally want request_queue or
sometimes the gendisk, so this removes a layer of indirection all
over the stack.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

This helper allows looking up a partion under RCU protection without
grabbing a reference to it.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJens Axboe <axboe@kernel.dk>