21 Mar, 2020
1 commit
-
[ Upstream commit 01e99aeca3979600302913cef3f89076786f32c8 ]
For some reason, device may be in one situation which can't handle
FS request, so STS_RESOURCE is always returned and the FS request
will be added to hctx->dispatch. However passthrough request may
be required at that time for fixing the problem. If passthrough
request is added to scheduler queue, there isn't any chance for
blk-mq to dispatch it given we prioritize requests in hctx->dispatch.
Then the FS IO request may never be completed, and IO hang is caused.So passthrough request has to be added to hctx->dispatch directly
for fixing the IO hang.Fix this issue by inserting passthrough request into hctx->dispatch
directly together withing adding FS request to the tail of
hctx->dispatch in blk_mq_dispatch_rq_list(). Actually we add FS request
to tail of hctx->dispatch at default, see blk_mq_request_bypass_insert().Then it becomes consistent with original legacy IO request
path, in which passthrough request is always added to q->queue_head.Cc: Dongli Zhang
Cc: Christoph Hellwig
Cc: Ewan D. Milne
Signed-off-by: Ming Lei
Signed-off-by: Jens Axboe
Signed-off-by: Sasha Levin
12 Jan, 2020
1 commit
-
[ Upstream commit b3c6a59975415bde29cfd76ff1ab008edbf614a9 ]
Avoid that running test nvme/012 from the blktests suite triggers the
following false positive lockdep complaint:============================================
WARNING: possible recursive locking detected
5.0.0-rc3-xfstests-00015-g1236f7d60242 #841 Not tainted
--------------------------------------------
ksoftirqd/1/16 is trying to acquire lock:
000000000282032e (&(&fq->mq_flush_lock)->rlock){..-.}, at: flush_end_io+0x4e/0x1d0but task is already holding lock:
00000000cbadcbc2 (&(&fq->mq_flush_lock)->rlock){..-.}, at: flush_end_io+0x4e/0x1d0other info that might help us debug this:
Possible unsafe locking scenario:CPU0
----
lock(&(&fq->mq_flush_lock)->rlock);
lock(&(&fq->mq_flush_lock)->rlock);*** DEADLOCK ***
May be due to missing lock nesting notation
1 lock held by ksoftirqd/1/16:
#0: 00000000cbadcbc2 (&(&fq->mq_flush_lock)->rlock){..-.}, at: flush_end_io+0x4e/0x1d0stack backtrace:
CPU: 1 PID: 16 Comm: ksoftirqd/1 Not tainted 5.0.0-rc3-xfstests-00015-g1236f7d60242 #841
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
dump_stack+0x67/0x90
__lock_acquire.cold.45+0x2b4/0x313
lock_acquire+0x98/0x160
_raw_spin_lock_irqsave+0x3b/0x80
flush_end_io+0x4e/0x1d0
blk_mq_complete_request+0x76/0x110
nvmet_req_complete+0x15/0x110 [nvmet]
nvmet_bio_done+0x27/0x50 [nvmet]
blk_update_request+0xd7/0x2d0
blk_mq_end_request+0x1a/0x100
blk_flush_complete_seq+0xe5/0x350
flush_end_io+0x12f/0x1d0
blk_done_softirq+0x9f/0xd0
__do_softirq+0xca/0x440
run_ksoftirqd+0x24/0x50
smpboot_thread_fn+0x113/0x1e0
kthread+0x121/0x140
ret_from_fork+0x3a/0x50Cc: Christoph Hellwig
Cc: Ming Lei
Cc: Hannes Reinecke
Signed-off-by: Bart Van Assche
Signed-off-by: Jens Axboe
Signed-off-by: Sasha Levin
27 Sep, 2019
1 commit
-
We got a null pointer deference BUG_ON in blk_mq_rq_timed_out()
as following:[ 108.825472] BUG: kernel NULL pointer dereference, address: 0000000000000040
[ 108.827059] PGD 0 P4D 0
[ 108.827313] Oops: 0000 [#1] SMP PTI
[ 108.827657] CPU: 6 PID: 198 Comm: kworker/6:1H Not tainted 5.3.0-rc8+ #431
[ 108.829503] Workqueue: kblockd blk_mq_timeout_work
[ 108.829913] RIP: 0010:blk_mq_check_expired+0x258/0x330
[ 108.838191] Call Trace:
[ 108.838406] bt_iter+0x74/0x80
[ 108.838665] blk_mq_queue_tag_busy_iter+0x204/0x450
[ 108.839074] ? __switch_to_asm+0x34/0x70
[ 108.839405] ? blk_mq_stop_hw_queue+0x40/0x40
[ 108.839823] ? blk_mq_stop_hw_queue+0x40/0x40
[ 108.840273] ? syscall_return_via_sysret+0xf/0x7f
[ 108.840732] blk_mq_timeout_work+0x74/0x200
[ 108.841151] process_one_work+0x297/0x680
[ 108.841550] worker_thread+0x29c/0x6f0
[ 108.841926] ? rescuer_thread+0x580/0x580
[ 108.842344] kthread+0x16a/0x1a0
[ 108.842666] ? kthread_flush_work+0x170/0x170
[ 108.843100] ret_from_fork+0x35/0x40The bug is caused by the race between timeout handle and completion for
flush request.When timeout handle function blk_mq_rq_timed_out() try to read
'req->q->mq_ops', the 'req' have completed and reinitiated by next
flush request, which would call blk_rq_init() to clear 'req' as 0.After commit 12f5b93145 ("blk-mq: Remove generation seqeunce"),
normal requests lifetime are protected by refcount. Until 'rq->ref'
drop to zero, the request can really be free. Thus, these requests
cannot been reused before timeout handle finish.However, flush request has defined .end_io and rq->end_io() is still
called even if 'rq->ref' doesn't drop to zero. After that, the 'flush_rq'
can be reused by the next flush request handle, resulting in null
pointer deference BUG ON.We fix this problem by covering flush request with 'rq->ref'.
If the refcount is not zero, flush_end_io() return and wait the
last holder recall it. To record the request status, we add a new
entry 'rq_status', which will be used in flush_end_io().Cc: Christoph Hellwig
Cc: Keith Busch
Cc: Bart Van Assche
Cc: stable@vger.kernel.org # v4.18+
Reviewed-by: Ming Lei
Reviewed-by: Bob Liu
Signed-off-by: Yufen Yu-------
v2:
- move rq_status from struct request to struct blk_flush_queue
v3:
- remove unnecessary '{}' pair.
v4:
- let spinlock to protect 'fq->rq_status'
v5:
- move rq_status after flush_running_idx member of struct blk_flush_queue
Signed-off-by: Jens Axboe
01 May, 2019
1 commit
-
All these files have some form of the usual GPLv2 boilerplate. Switch
them to use SPDX tags instead.Reviewed-by: Chaitanya Kulkarni
Signed-off-by: Christoph Hellwig
Signed-off-by: Jens Axboe
25 Mar, 2019
1 commit
-
Expect arguments, blk_mq_put_driver_tag_hctx() and blk_mq_put_driver_tag()
is same. We can just use argument 'request' to put tag by blk_mq_put_driver_tag().
Then we can remove the unused blk_mq_put_driver_tag_hctx().Signed-off-by: Yufen Yu
Signed-off-by: Jens Axboe
30 Jan, 2019
1 commit
-
Florian reported a io hung issue when fsync(). It should be
triggered by following race condition.data + post flush a flush
blk_flush_complete_seq
case REQ_FSEQ_DATA
blk_flush_queue_rq
issued to driver blk_mq_dispatch_rq_list
try to issue a flush req
failed due to NON-NCQ command
.queue_rq return BLK_STS_DEV_RESOURCErequest completion
req->end_io // doesn't check RESTART
mq_flush_data_end_io
case REQ_FSEQ_POSTFLUSH
blk_kick_flush
do nothing because previous flush
has not been completed
blk_mq_run_hw_queue
insert rq to hctx->dispatch
due to RESTART is still set, do nothingTo fix this, replace the blk_mq_run_hw_queue in mq_flush_data_end_io
with blk_mq_sched_restart to check and clear the RESTART flag.Fixes: bd166ef1 (blk-mq-sched: add framework for MQ capable IO schedulers)
Reported-by: Florian Stecker
Tested-by: Florian Stecker
Signed-off-by: Jianchao Wang
Signed-off-by: Jens Axboe
16 Nov, 2018
2 commits
-
Various spots check for q->mq_ops being non-NULL, but provide
a helper to do this instead.Where the ->mq_ops != NULL check is redundant, remove it.
Since mq == rq-based now that legacy is gone, get rid of the
queue_is_rq_based() and just use queue_is_mq() everywhere.Reviewed-by: Christoph Hellwig
Signed-off-by: Jens Axboe -
Only the mq locking is left in the flush state machine.
Reviewed-by: Hannes Reinecke
Signed-off-by: Christoph Hellwig
Signed-off-by: Jens Axboe
08 Nov, 2018
4 commits
-
We call blk_mq_map_queue() a lot, at least two times for each
request per IO, sometimes more. Since we now have an indirect
call as well in that function. cache the mapping so we don't
have to re-call blk_mq_map_queue() for the same request
multiple times.Reviewed-by: Keith Busch
Reviewed-by: Sagi Grimberg
Reviewed-by: Hannes Reinecke
Signed-off-by: Jens Axboe -
Prep patch for being able to place request based not just on
CPU location, but also on the type of request.Reviewed-by: Hannes Reinecke
Reviewed-by: Keith Busch
Signed-off-by: Jens Axboe -
Now that blk_flush_queue_rq() always returns false, we can
remove that return value. That bubbles through the stack,
allowing us to remove a bunch of state tracking around it.Tested-by: Ming Lei
Reviewed-by: Omar Sandoval
Signed-off-by: Jens Axboe -
Reviewed-by: Hannes Reinecke
Tested-by: Ming Lei
Reviewed-by: Omar Sandoval
Signed-off-by: Jens Axboe
14 Oct, 2018
1 commit
-
blk_mq_realloc_hw_ctxs could be invoked during update hw queues.
At the momemt, IO is blocked. Change the gfp flags from GFP_KERNEL
to GFP_NOIO to avoid forever hang during memory allocation in
blk_mq_realloc_hw_ctxs.Signed-off-by: Jianchao Wang
Signed-off-by: Jens Axboe
09 Jun, 2018
1 commit
-
A recent commit reused the original request flags for the flush
queue handling. However, for some of the kick flush cases, the
original request was already completed. This caused a use after
free, if blk-mq wasn't used.Fixes: 84fca1b0c461 ("block: pass failfast and driver-specific flags to flush requests")
Reported-by: Dmitry Vyukov
Signed-off-by: Jens Axboe
06 Jun, 2018
1 commit
-
If flush requests are being sent to the device we need to inherit the
failfast and driver-specific flags, too, otherwise I/O will fail.Reviewed-by: Christoph Hellwig
Signed-off-by: Hannes Reinecke
Signed-off-by: Jens Axboe
05 Nov, 2017
3 commits
-
The idea behind it is simple:
1) for none scheduler, driver tag has to be borrowed for flush rq,
otherwise we may run out of tag, and that causes an IO hang. And
get/put driver tag is actually noop for none, so reordering tags
isn't necessary at all.2) for a real I/O scheduler, we need not allocate a driver tag upfront
for flush rq. It works just fine to follow the same approach as
normal requests: allocate driver tag for each rq just before calling
->queue_rq().One driver visible change is that the driver tag isn't shared in the
flush request sequence. That won't be a problem, since we always do that
in legacy path.Then flush rq need not be treated specially wrt. get/put driver tag.
This cleans up the code - for instance, reorder_tags_to_front() can be
removed, and we needn't worry about request ordering in dispatch list
for avoiding I/O deadlock.Also we have to put the driver tag before requeueing.
Signed-off-by: Ming Lei
Signed-off-by: Jens Axboe -
In the following patch, we will use RQF_FLUSH_SEQ to decide:
1) if the flag isn't set, the flush rq need to be inserted via
blk_insert_flush()2) otherwise, the flush rq need to be dispatched directly since
it is in flush machinery now.So we use blk_mq_request_bypass_insert() for requests of bypassing
flush machinery, just like the legacy path did.Signed-off-by: Ming Lei
Signed-off-by: Jens Axboe -
blk_insert_flush() should only insert request since run queue always
follows it.In case of bypassing flush, we don't need to run queue because every
blk_insert_flush() follows one run queue.Signed-off-by: Ming Lei
Signed-off-by: Jens Axboe
26 Aug, 2017
1 commit
-
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: Omar Sandoval
Signed-off-by: Jens Axboe
24 Aug, 2017
1 commit
-
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: Christoph Hellwig
Signed-off-by: Jens Axboe
21 Jun, 2017
1 commit
-
Instead of documenting the locking assumptions of most block layer
functions as a comment, use lockdep_assert_held() to verify locking
assumptions at runtime.Signed-off-by: Bart Van Assche
Reviewed-by: Christoph Hellwig
Cc: Hannes Reinecke
Cc: Omar Sandoval
Cc: Ming Lei
Signed-off-by: Jens Axboe
09 Jun, 2017
1 commit
-
Currently we use nornal Linux errno values in the block layer, and while
we accept any error a few have overloaded magic meanings. This patch
instead introduces a new blk_status_t value that holds block layer specific
status codes and explicitly explains their meaning. Helpers to convert from
and to the previous special meanings are provided for now, but I suspect
we want to get rid of them in the long run - those drivers that have a
errno input (e.g. networking) usually get errnos that don't know about
the special block layer overloads, and similarly returning them to userspace
will usually return somethings that strictly speaking isn't correct
for file system operations, but that's left as an exercise for later.For now the set of errors is a very limited set that closely corresponds
to the previous overloaded errno values, but there is some low hanging
fruite to improve it.blk_status_t (ab)uses the sparse __bitwise annotations to allow for sparse
typechecking, so that we can easily catch places passing the wrong values.Signed-off-by: Christoph Hellwig
Signed-off-by: Jens Axboe
20 Apr, 2017
1 commit
-
blk_insert_flush should be using __blk_end_request to start with.
Signed-off-by: Christoph Hellwig
Signed-off-by: Jens Axboe
25 Mar, 2017
1 commit
-
blkdev_issue_flush() is now always synchronous, and it no longer has a
flags argument. So remove the part of the comment about the WAIT flag.Signed-off-by: Eric Biggers
Signed-off-by: Jens Axboe
18 Feb, 2017
1 commit
-
For blk-mq with scheduling, we can potentially end up with ALL
driver tags assigned and sitting on the flush queues. If we
defer because of an inlfight data request, then we can deadlock
if that data request doesn't already have a tag assigned.This fixes a deadlock with running the xfs/297 xfstest, where
thousands of syncs can cause the drive queue to stall.Signed-off-by: Jens Axboe
Reviewed-by: Omar Sandoval
01 Feb, 2017
1 commit
-
Instead of keeping two levels of indirection for requests types, fold it
all into the operations. The little caveat here is that previously
cmd_type only applied to struct request, while the request and bio op
fields were set to plain REQ_OP_READ/WRITE even for passthrough
operations.Instead this patch adds new REQ_OP_* for SCSI passthrough and driver
private requests, althought it has to add two for each so that we
can communicate the data in/out nature of the request.Signed-off-by: Christoph Hellwig
Signed-off-by: Jens Axboe
28 Jan, 2017
2 commits
-
This mirrors the blk-mq capabilities to allocate extra drivers-specific
data behind struct request by setting a cmd_size field, as well as having
a constructor / destructor for it.Signed-off-by: Christoph Hellwig
Reviewed-by: Martin K. Petersen
Reviewed-by: Hannes Reinecke
Signed-off-by: Jens Axboe -
Instead of letting the caller check this and handle the details
of inserting a flush request, put the logic in the scheduler
insertion function. This fixes direct flush insertion outside
of the usual make_request_fn calls, like from dm via
blk_insert_cloned_request().Signed-off-by: Jens Axboe
18 Jan, 2017
1 commit
-
This adds a set of hooks that intercepts the blk-mq path of
allocating/inserting/issuing/completing requests, allowing
us to develop a scheduler within that framework.We reuse the existing elevator scheduler API on the registration
side, but augment that with the scheduler flagging support for
the blk-mq interfce, and with a separate set of ops hooks for MQ
devices.We split driver and scheduler tags, so we can run the scheduling
independently of device queue depth.Signed-off-by: Jens Axboe
Reviewed-by: Bart Van Assche
Reviewed-by: Omar Sandoval
14 Dec, 2016
1 commit
-
Pull block layer updates from Jens Axboe:
"This is the main block pull request this series. Contrary to previous
release, I've kept the core and driver changes in the same branch. We
always ended up having dependencies between the two for obvious
reasons, so makes more sense to keep them together. That said, I'll
probably try and keep more topical branches going forward, especially
for cycles that end up being as busy as this one.The major parts of this pull request is:
- Improved support for O_DIRECT on block devices, with a small
private implementation instead of using the pig that is
fs/direct-io.c. From Christoph.- Request completion tracking in a scalable fashion. This is utilized
by two components in this pull, the new hybrid polling and the
writeback queue throttling code.- Improved support for polling with O_DIRECT, adding a hybrid mode
that combines pure polling with an initial sleep. From me.- Support for automatic throttling of writeback queues on the block
side. This uses feedback from the device completion latencies to
scale the queue on the block side up or down. From me.- Support from SMR drives in the block layer and for SD. From Hannes
and Shaun.- Multi-connection support for nbd. From Josef.
- Cleanup of request and bio flags, so we have a clear split between
which are bio (or rq) private, and which ones are shared. From
Christoph.- A set of patches from Bart, that improve how we handle queue
stopping and starting in blk-mq.- Support for WRITE_ZEROES from Chaitanya.
- Lightnvm updates from Javier/Matias.
- Supoort for FC for the nvme-over-fabrics code. From James Smart.
- A bunch of fixes from a whole slew of people, too many to name
here"* 'for-4.10/block' of git://git.kernel.dk/linux-block: (182 commits)
blk-stat: fix a few cases of missing batch flushing
blk-flush: run the queue when inserting blk-mq flush
elevator: make the rqhash helpers exported
blk-mq: abstract out blk_mq_dispatch_rq_list() helper
blk-mq: add blk_mq_start_stopped_hw_queue()
block: improve handling of the magic discard payload
blk-wbt: don't throttle discard or write zeroes
nbd: use dev_err_ratelimited in io path
nbd: reset the setup task for NBD_CLEAR_SOCK
nvme-fabrics: Add FC LLDD loopback driver to test FC-NVME
nvme-fabrics: Add target support for FC transport
nvme-fabrics: Add host support for FC transport
nvme-fabrics: Add FC transport LLDD api definitions
nvme-fabrics: Add FC transport FC-NVME definitions
nvme-fabrics: Add FC transport error codes to nvme.h
Add type 0x28 NVME type code to scsi fc headers
nvme-fabrics: patch target code in prep for FC transport support
nvme-fabrics: set sqe.command_id in core not transports
parser: add u64 number parser
nvme-rdma: align to generic ib_event logging helper
...
10 Dec, 2016
1 commit
-
Currently we pass in to run the queue async, but don't flag the
queue to be run. We don't need to run it async here, but we should
run it. So fixup the parameters.Signed-off-by: Jens Axboe
Reviewed-by: Hannes Reinecke
09 Nov, 2016
1 commit
-
If we insert a flush request, we clear REQ_PREFLUSH and/or REQ_FUA,
depending on flush settings. Since op_is_sync() factors those flags
in for deciding whether this request is sync or not, we should
set REQ_SYNC to avoid screwing up this accounting.This should be less fragile.
Reported-by: Logan Gunthorpe
Fixes: b685d3d65ac ("block: treat REQ_FUA and REQ_PREFLUSH as synchronous")
Signed-off-by: Jens Axboe
03 Nov, 2016
1 commit
-
Most blk_mq_requeue_request() and blk_mq_add_to_requeue_list() calls
are followed by kicking the requeue list. Hence add an argument to
these two functions that allows to kick the requeue list. This was
proposed by Christoph Hellwig.Signed-off-by: Bart Van Assche
Reviewed-by: Johannes Thumshirn
Reviewed-by: Christoph Hellwig
Cc: Hannes Reinecke
Reviewed-by: Sagi Grimberg
Signed-off-by: Jens Axboe
01 Nov, 2016
1 commit
-
Remove the WRITE_* and READ_SYNC wrappers, and just use the flags
directly. Where applicable this also drops usage of the
bio_set_op_attrs wrapper.Signed-off-by: Christoph Hellwig
Signed-off-by: Jens Axboe
28 Oct, 2016
2 commits
-
Now that we don't need the common flags to overflow outside the range
of a 32-bit type we can encode them the same way for both the bio and
request fields. This in addition allows us to place the operation
first (and make some room for more ops while we're at it) and to
stop having to shift around the operation values.In addition this allows passing around only one value in the block layer
instead of two (and eventuall also in the file systems, but we can do
that later) and thus clean up a lot of code.Last but not least this allows decreasing the size of the cmd_flags
field in struct request to 32-bits. Various functions passing this
value could also be updated, but I'd like to avoid the churn for now.Signed-off-by: Christoph Hellwig
Signed-off-by: Jens Axboe -
A lot of the REQ_* flags are only used on struct requests, and only of
use to the block layer and a few drivers that dig into struct request
internals.This patch adds a new req_flags_t rq_flags field to struct request for
them, and thus dramatically shrinks the number of common requests. It
also removes the unfortunate situation where we have to fit the fields
from the same enum into 32 bits for struct bio and 64 bits for
struct request.Signed-off-by: Christoph Hellwig
Reviewed-by: Shaun Tancheff
Signed-off-by: Jens Axboe
26 Oct, 2016
1 commit
-
This patch fixes one issue reported by Kent, which can
be triggered in bcachefs over sata disk. Actually it
is a generic issue in block flush vs. blk-tag.Cc: Christoph Hellwig
Reported-by: Kent Overstreet
Signed-off-by: Ming Lei
Signed-off-by: Jens Axboe
15 Sep, 2016
1 commit
-
All drivers use the default, so provide an inline version of it. If we
ever need other queue mapping we can add an optional method back,
although supporting will also require major changes to the queue setup
code.This provides better code generation, and better debugability as well.
Signed-off-by: Christoph Hellwig
Reviewed-by: Keith Busch
Signed-off-by: Jens Axboe
08 Jun, 2016
2 commits
-
To avoid confusion between REQ_OP_FLUSH, which is handled by
request_fn drivers, and upper layers requesting the block layer
perform a flush sequence along with possibly a WRITE, this patch
renames REQ_FLUSH to REQ_PREFLUSH.Signed-off-by: Mike Christie
Reviewed-by: Christoph Hellwig
Reviewed-by: Hannes Reinecke
Signed-off-by: Jens Axboe -
This adds a REQ_OP_FLUSH operation that is sent to request_fn
based drivers by the block layer's flush code, instead of
sending requests with the request->cmd_flags REQ_FLUSH bit set.Signed-off-by: Mike Christie
Reviewed-by: Christoph Hellwig
Reviewed-by: Hannes Reinecke
Signed-off-by: Jens Axboe
