If we attempt a direct issue to a SCSI device, and it returns BUSY, then
we queue the request up normally. However, the SCSI layer may have
already setup SG tables etc for this particular command. If we later
merge with this request, then the old tables are no longer valid. Once
we issue the IO, we only read/write the original part of the request,
not the new state of it.

This causes data corruption, and is most often noticed with the file
system complaining about the just read data being invalid:

[ 235.934465] EXT4-fs error (device sda1): ext4_iget:4831: inode #7142: comm dpkg-query: bad extra_isize 24937 (inode size 256)

because most of it is garbage...

This doesn't happen from the normal issue path, as we will simply defer
the request to the hardware queue dispatch list if we fail. Once it's on
the dispatch list, we never merge with it.

Fix this from the direct issue path by flagging the request as
REQ_NOMERGE so we don't change the size of it before issue.

See also:
https://bugzilla.kernel.org/show_bug.cgi?id=201685

Tested-by: Guenter Roeck <linux@roeck-us.net>
Fixes: 6ce3dd6eec1 ("blk-mq: issue directly if hw queue isn't busy in case of 'none'")
Cc: stable@vger.kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>

These devices support read zero after trim (RZAT), as they advertise to
the OS. However, the OS doesn't believe the SSDs unless they are
explicitly whitelisted.

Acked-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Juha-Matti Tilli <juha-matti.tilli@iki.fi>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Pull NVMe fixes from Christoph:

"Various fixlets all over."

* 'nvme-4.20' of git://git.infradead.org/nvme:
nvme-rdma: fix double freeing of async event data
nvme: flush namespace scanning work just before removing namespaces
nvme: warn when finding multi-port subsystems without multipathing enabled
nvme-pci: fix surprise removal
nvme-fc: initialize nvme_req(rq)->ctrl after calling __nvme_fc_init_request()
nvme: Free ctrl device name on init failure

There are actually two kinds of discard merge:

- one is the normal discard merge, just like normal read/write request,
and call it single-range discard

- another is the multi-range discard, queue_max_discard_segments(rq->q) > 1

For the former case, queue_max_discard_segments(rq->q) is 1, and we
should handle this kind of discard merge like the normal read/write
request.

This patch fixes the following kernel panic issue[1], which is caused by
not removing the single-range discard request from elevator queue.

Guangwu has one raid discard test case, in which this issue is a bit
easier to trigger, and I verified that this patch can fix the kernel
panic issue in Guangwu's test case.

[1] kernel panic log from Jens's report

BUG: unable to handle kernel NULL pointer dereference at 0000000000000148
PGD 0 P4D 0.
Oops: 0000 [#1] SMP PTI
CPU: 37 PID: 763 Comm: kworker/37:1H Not tainted \
4.20.0-rc3-00649-ge64d9a554a91-dirty #14 Hardware name: Wiwynn \
Leopard-Orv2/Leopard-DDR BW, BIOS LBM08 03/03/2017 Workqueue: kblockd \
blk_mq_run_work_fn RIP: \
0010:blk_mq_get_driver_tag+0x81/0x120 Code: 24 \
10 48 89 7c 24 20 74 21 83 fa ff 0f 95 c0 48 8b 4c 24 28 65 48 33 0c 25 28 00 00 00 \
0f 85 96 00 00 00 48 83 c4 30 5b 5d c3 <48> 8b 87 48 01 00 00 8b 40 04 39 43 20 72 37 \
f6 87 b0 00 00 00 02 RSP: 0018:ffffc90004aabd30 EFLAGS: 00010246 \
RAX: 0000000000000003 RBX: ffff888465ea1300 RCX: ffffc90004aabde8
RDX: 00000000ffffffff RSI: ffffc90004aabde8 RDI: 0000000000000000
RBP: 0000000000000000 R08: ffff888465ea1348 R09: 0000000000000000
R10: 0000000000001000 R11: 00000000ffffffff R12: ffff888465ea1300
R13: 0000000000000000 R14: ffff888465ea1348 R15: ffff888465d10000
FS: 0000000000000000(0000) GS:ffff88846f9c0000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000148 CR3: 000000000220a003 CR4: 00000000003606e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
blk_mq_dispatch_rq_list+0xec/0x480
? elv_rb_del+0x11/0x30
blk_mq_do_dispatch_sched+0x6e/0xf0
blk_mq_sched_dispatch_requests+0xfa/0x170
__blk_mq_run_hw_queue+0x5f/0xe0
process_one_work+0x154/0x350
worker_thread+0x46/0x3c0
kthread+0xf5/0x130
? process_one_work+0x350/0x350
? kthread_destroy_worker+0x50/0x50
ret_from_fork+0x1f/0x30
Modules linked in: sb_edac x86_pkg_temp_thermal intel_powerclamp coretemp kvm_intel \
kvm switchtec irqbypass iTCO_wdt iTCO_vendor_support efivars cdc_ether usbnet mii \
cdc_acm i2c_i801 lpc_ich mfd_core ipmi_si ipmi_devintf ipmi_msghandler acpi_cpufreq \
button sch_fq_codel nfsd nfs_acl lockd grace auth_rpcgss oid_registry sunrpc nvme \
nvme_core fuse sg loop efivarfs autofs4 CR2: 0000000000000148 \

---[ end trace 340a1fb996df1b9b ]---
RIP: 0010:blk_mq_get_driver_tag+0x81/0x120
Code: 24 10 48 89 7c 24 20 74 21 83 fa ff 0f 95 c0 48 8b 4c 24 28 65 48 33 0c 25 28 \
00 00 00 0f 85 96 00 00 00 48 83 c4 30 5b 5d c3 <48> 8b 87 48 01 00 00 8b 40 04 39 43 \
20 72 37 f6 87 b0 00 00 00 02

Fixes: 445251d0f4d329a ("blk-mq: fix discard merge with scheduler attached")
Reported-by: Jens Axboe <axboe@kernel.dk>
Cc: Guangwu Zhang <guazhang@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Jianchao Wang <jianchao.w.wang@oracle.com>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Some error paths in configuration of admin queue free data buffer
associated with async request SQE without resetting the data buffer
pointer to NULL, This buffer is also freed up again if the controller
is shutdown or reset.

Signed-off-by: Prabhath Sajeepa <psajeepa@purestorage.com>
Reviewed-by: Roland Dreier <roland@purestorage.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

commit e259221763a40403d5bb232209998e8c45804ab8 ("fs: simplify the
generic_write_sync prototype") reworked callers of generic_write_sync(),
and ended up dropping the error return for the directio path. Prior to
that commit, in dio_complete(), an error would be bubbled up the stack,
but after that commit, errors passed on to dio_complete were eaten up.

This was reported on the list earlier, and a fix was proposed in
https://lore.kernel.org/lkml/20160921141539.GA17898@infradead.org/, but
never followed up with. We recently hit this bug in our testing where
fencing io errors, which were previously erroring out with EIO, were
being returned as success operations after this commit.

The fix proposed on the list earlier was a little short -- it would have
still called generic_write_sync() in case `ret` already contained an
error. This fix ensures generic_write_sync() is only called when there's
no pending error in the write. Additionally, transferred is replaced
with ret to bring this code in line with other callers.

Fixes: e259221763a4 ("fs: simplify the generic_write_sync prototype")
Reported-by: Ravi Nankani <rnankani@amazon.com>
Signed-off-by: Maximilian Heyne <mheyne@amazon.de>
Reviewed-by: Christoph Hellwig <hch@lst.de>
CC: Torsten Mehlan <tomeh@amazon.de>
CC: Uwe Dannowski <uwed@amazon.de>
CC: Amit Shah <aams@amazon.de>
CC: David Woodhouse <dwmw@amazon.co.uk>
CC: stable@vger.kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>

nvme_stop_ctrl can be called also for reset flow and there is no need to
flush the scan_work as namespaces are not being removed. This can cause
deadlock in rdma, fc and loop drivers since nvme_stop_ctrl barriers
before controller teardown (and specifically I/O cancellation of the
scan_work itself) takes place, but the scan_work will be blocked anyways
so there is no need to flush it.

Instead, move scan_work flush to nvme_remove_namespaces() where it really
needs to flush.

Reported-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by: Keith Busch <keith.busch@intel.com>
Reviewed by: James Smart <jsmart2021@gmail.com>
Tested-by: Ewan D. Milne <emilne@redhat.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

Pull NVMe fix from Christoph.

* 'nvme-4.20' of git://git.infradead.org/nvme:
nvme-fc: resolve io failures during connect

Without CONFIG_NVME_MULTIPATH enabled a multi-port subsystem might
show up as invididual devices and cause problems, warn about it.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>

c2856ae2f315d ("blk-mq: quiesce queue before freeing queue") has
already fixed this race, however the implied synchronize_rcu()
in blk_mq_quiesce_queue() can slow down LUN probe a lot, so caused
performance regression.

Then 1311326cf4755c7 ("blk-mq: avoid to synchronize rcu inside blk_cleanup_queue()")
tried to quiesce queue for avoiding unnecessary synchronize_rcu()
only when queue initialization is done, because it is usual to see
lots of inexistent LUNs which need to be probed.

However, turns out it isn't safe to quiesce queue only when queue
initialization is done. Because when one SCSI command is completed,
the user of sending command can be waken up immediately, then the
scsi device may be removed, meantime the run queue in scsi_end_request()
is still in-progress, so kernel panic can be caused.

In Red Hat QE lab, there are several reports about this kind of kernel
panic triggered during kernel booting.

This patch tries to address the issue by grabing one queue usage
counter during freeing one request and the following run queue.

Fixes: 1311326cf4755c7 ("blk-mq: avoid to synchronize rcu inside blk_cleanup_queue()")
Cc: Andrew Jones <drjones@redhat.com>
Cc: Bart Van Assche <bart.vanassche@wdc.com>
Cc: linux-scsi@vger.kernel.org
Cc: Martin K. Petersen <martin.petersen@oracle.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: James E.J. Bottomley <jejb@linux.vnet.ibm.com>
Cc: stable <stable@vger.kernel.org>
Cc: jianchao.wang <jianchao.w.wang@oracle.com>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

If an io error occurs on an io issued while connecting, recovery
of the io falls flat as the state checking ends up nooping the error
handler.

Create an err_work work item that is scheduled upon an io error while
connecting. The work thread terminates all io on all queues and marks
the queues as not connected. The termination of the io will return
back to the callee, which will then back out of the connection attempt
and will reschedule, if possible, the connection attempt.

The changes:
- in case there are several commands hitting the error handler, a
state flag is kept so that the error work is only scheduled once,
on the first error. The subsequent errors can be ignored.
- The calling sequence to stop keep alive and terminate the queues
and their io is lifted from the reset routine. Made a small
service routine used by both reset and err_work.
- During debugging, found that the teardown path can reference
an uninitialized pointer, resulting in a NULL pointer oops.
The aen_ops weren't initialized yet. Add validation on their
initialization before calling the teardown routine.

Signed-off-by: James Smart <jsmart2021@gmail.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

When a PCIe NVMe device is not present, nvme_dev_remove_admin() calls
blk_cleanup_queue() on the admin queue, which frees the hctx for that
queue. Moments later, on the same path nvme_kill_queues() calls
blk_mq_unquiesce_queue() on admin queue and tries to access hctx of it,
which leads to following OOPS:

Oops: 0000 [#1] SMP PTI
RIP: 0010:sbitmap_any_bit_set+0xb/0x40
Call Trace:
blk_mq_run_hw_queue+0xd5/0x150
blk_mq_run_hw_queues+0x3a/0x50
nvme_kill_queues+0x26/0x50
nvme_remove_namespaces+0xb2/0xc0
nvme_remove+0x60/0x140
pci_device_remove+0x3b/0xb0

Fixes: cb4bfda62afa2 ("nvme-pci: fix hot removal during error handling")
Signed-off-by: Igor Konopko <igor.j.konopko@intel.com>
Reviewed-by: Keith Busch <keith.busch@intel.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

A discard cleanup merged into 4.20-rc2 causes fstests xfs/259 to
fall into an endless loop in the discard code. The test is creating
a device that is exactly 2^32 sectors in size to test mkfs boundary
conditions around the 32 bit sector overflow region.

mkfs issues a discard for the entire device size by default, and
hence this throws a sector count of 2^32 into
blkdev_issue_discard(). It takes the number of sectors to discard as
a sector_t - a 64 bit value.

The commit ba5d73851e71 ("block: cleanup __blkdev_issue_discard")
takes this sector count and casts it to a 32 bit value before
comapring it against the maximum allowed discard size the device
has. This truncates away the upper 32 bits, and so if the lower 32
bits of the sector count is zero, it starts issuing discards of
length 0. This causes the code to fall into an endless loop, issuing
a zero length discards over and over again on the same sector.

Fixes: ba5d73851e71 ("block: cleanup __blkdev_issue_discard")
Tested-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Dave Chinner <dchinner@redhat.com>

Killed pointless WARN_ON().

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

__nvme_fc_init_request() invokes memset() on the nvme_fcp_op_w_sgl structure, which
NULLed-out the nvme_req(req)->ctrl field previously set by nvme_fc_init_request().
This apparently was not referenced until commit faf4a44fff ("nvme: support traffic
based keep-alive") which now results in a crash in nvme_complete_rq():

[ 8386.897130] RIP: 0010:panic+0x220/0x26c
[ 8386.901406] Code: 83 3d 6f ee 72 01 00 74 05 e8 e8 54 02 00 48 c7 c6 40 fd 5b b4 48 c7 c7 d8 8d c6 b3 31e
[ 8386.922359] RSP: 0018:ffff99650019fc40 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13
[ 8386.930804] RAX: 0000000000000046 RBX: 0000000000000000 RCX: 0000000000000006
[ 8386.938764] RDX: 0000000000000000 RSI: 0000000000000082 RDI: ffff8e325f8168b0
[ 8386.946725] RBP: ffff99650019fcb0 R08: 0000000000000000 R09: 00000000000004f8
[ 8386.954687] R10: 0000000000000000 R11: ffff99650019f9b8 R12: ffffffffb3c55f3c
[ 8386.962648] R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000001
[ 8386.970613] oops_end+0xd1/0xe0
[ 8386.974116] no_context+0x1b2/0x3c0
[ 8386.978006] do_page_fault+0x32/0x140
[ 8386.982090] page_fault+0x1e/0x30
[ 8386.985786] RIP: 0010:nvme_complete_rq+0x65/0x1d0 [nvme_core]
[ 8386.992195] Code: 41 bc 03 00 00 00 74 16 0f 86 c3 00 00 00 66 3d 83 00 41 bc 06 00 00 00 0f 85 e7 00 000
[ 8387.013147] RSP: 0018:ffff99650019fe18 EFLAGS: 00010246
[ 8387.018973] RAX: 0000000000000000 RBX: ffff8e322ae51280 RCX: 0000000000000001
[ 8387.026935] RDX: 0000000000000400 RSI: 0000000000000001 RDI: ffff8e322ae51280
[ 8387.034897] RBP: ffff8e322ae51280 R08: 0000000000000000 R09: ffffffffb2f0b890
[ 8387.042859] R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000000
[ 8387.050821] R13: 0000000000000100 R14: 0000000000000004 R15: ffff8e2b0446d990
[ 8387.058782] ? swiotlb_unmap_page+0x40/0x40
[ 8387.063448] nvme_fc_complete_rq+0x2d/0x70 [nvme_fc]
[ 8387.068986] blk_done_softirq+0xa1/0xd0
[ 8387.073264] __do_softirq+0xd6/0x2a9
[ 8387.077251] run_ksoftirqd+0x26/0x40
[ 8387.081238] smpboot_thread_fn+0x10e/0x160
[ 8387.085807] kthread+0xf8/0x130
[ 8387.089309] ? sort_range+0x20/0x20
[ 8387.093198] ? kthread_stop+0x110/0x110
[ 8387.097475] ret_from_fork+0x35/0x40
[ 8387.101462] ---[ end trace 7106b0adf5e422f8 ]---

Fixes: faf4a44fff ("nvme: support traffic based keep-alive")
Signed-off-by: Ewan D. Milne <emilne@redhat.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>