linux-stable.git/block, branch v4.18.17

blk-mq: I/O and timer unplugs are inverted in blktrace

2018-10-13T07:33:09+00:00

commit 587562d0c7cd6861f4f90a2eb811cccb1a376f5f upstream.

trace_block_unplug() takes true for explicit unplugs and false for
implicit unplugs.  schedule() unplugs are implicit and should be
reported as timer unplugs.  While correct in the legacy code, this has
been inverted in blk-mq since 4.11.

Cc: stable@vger.kernel.org
Fixes: bd166ef183c2 ("blk-mq-sched: add framework for MQ capable IO schedulers")
Reviewed-by: Omar Sandoval 
Signed-off-by: Ilya Dryomov 
Signed-off-by: Jens Axboe 
Signed-off-by: Greg Kroah-Hartman

Revert "blk-throttle: fix race between blkcg_bio_issue_check() and cgroup_rmdir()"

2018-10-10T06:55:54+00:00

[ Upstream commit 6b06546206868f723f2061d703a3c3c378dcbf4c ]

This reverts commit 4c6994806f708559c2812b73501406e21ae5dcd0.

Destroying blkgs is tricky because of the nature of the relationship. A
blkg should go away when either a blkcg or a request_queue goes away.
However, blkg's pin the blkcg to ensure they remain valid. To break this
cycle, when a blkcg is offlined, blkgs put back their css ref. This
eventually lets css_free() get called which frees the blkcg.

The above commit (4c6994806f70) breaks this order of events by trying to
destroy blkgs in css_free(). As the blkgs still hold references to the
blkcg, css_free() is never called.

The race between blkcg_bio_issue_check() and cgroup_rmdir() will be
addressed in the following patch by delaying destruction of a blkg until
all writeback associated with the blkcg has been finished.

Fixes: 4c6994806f70 ("blk-throttle: fix race between blkcg_bio_issue_check() and cgroup_rmdir()")
Reviewed-by: Josef Bacik 
Signed-off-by: Dennis Zhou 
Cc: Jiufei Xue 
Cc: Joseph Qi 
Cc: Tejun Heo 
Cc: Jens Axboe 
Signed-off-by: Jens Axboe 
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

block: fix deadline elevator drain for zoned block devices

2018-10-03T23:59:17+00:00

commit 854f31ccdd7964c9c2e68da234a3a8aedb51cf6b upstream.

When the deadline scheduler is used with a zoned block device, writes
to a zone will be dispatched one at a time. This causes the warning
message:

deadline: forced dispatching is broken (nr_sorted=X), please report this

to be displayed when switching to another elevator with the legacy I/O
path while write requests to a zone are being retained in the scheduler
queue.

Prevent this message from being displayed when executing
elv_drain_elevator() for a zoned block device. __blk_drain_queue() will
loop until all writes are dispatched and completed, resulting in the
desired elevator queue drain without extensive modifications to the
deadline code itself to handle forced-dispatch calls.

Signed-off-by: Damien Le Moal 
Fixes: 8dc8146f9c92 ("deadline-iosched: Introduce zone locking support")
Cc: stable@vger.kernel.org
Signed-off-by: Jens Axboe 
Signed-off-by: Greg Kroah-Hartman

blk-mq: avoid to synchronize rcu inside blk_cleanup_queue()

2018-09-26T06:39:43+00:00

[ Upstream commit 1311326cf4755c7ffefd20f576144ecf46d9906b ]

SCSI probing may synchronously create and destroy a lot of request_queues
for non-existent devices. Any synchronize_rcu() in queue creation or
destroy path may introduce long latency during booting, see detailed
description in comment of blk_register_queue().

This patch removes one synchronize_rcu() inside blk_cleanup_queue()
for this case, commit c2856ae2f315d75(blk-mq: quiesce queue before freeing queue)
needs synchronize_rcu() for implementing blk_mq_quiesce_queue(), but
when queue isn't initialized, it isn't necessary to do that since
only pass-through requests are involved, no original issue in
scsi_execute() at all.

Without this patch and previous one, it may take more 20+ seconds for
virtio-scsi to complete disk probe. With the two patches, the time becomes
less than 100ms.

Fixes: c2856ae2f315d75 ("blk-mq: quiesce queue before freeing queue")
Reported-by: Andrew Jones 
Cc: Omar Sandoval 
Cc: Bart Van Assche 
Cc: linux-scsi@vger.kernel.org
Cc: "Martin K. Petersen" 
Cc: Christoph Hellwig 
Tested-by: Andrew Jones 
Signed-off-by: Ming Lei 
Signed-off-by: Jens Axboe 
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

blk-mq: only attempt to merge bio if there is rq in sw queue

2018-09-26T06:39:43+00:00

[ Upstream commit b04f50ab8a74129b3041a2836c33c916be3c6667 ]

Only attempt to merge bio iff the ctx->rq_list isn't empty, because:

1) for high-performance SSD, most of times dispatch may succeed, then
there may be nothing left in ctx->rq_list, so don't try to merge over
sw queue if it is empty, then we can save one acquiring of ctx->lock

2) we can't expect good merge performance on per-cpu sw queue, and missing
one merge on sw queue won't be a big deal since tasks can be scheduled from
one CPU to another.

Cc: Laurence Oberman 
Cc: Omar Sandoval 
Cc: Bart Van Assche 
Tested-by: Kashyap Desai 
Reported-by: Kashyap Desai 
Reviewed-by: Christoph Hellwig 
Signed-off-by: Ming Lei 
Signed-off-by: Jens Axboe 
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

block: allow max_discard_segments to be stacked

2018-09-26T06:39:23+00:00

[ Upstream commit 42c9cdfe1e11e083dceb0f0c4977b758cf7403b9 ]

Set max_discard_segments to USHRT_MAX in blk_set_stacking_limits() so
that blk_stack_limits() can stack up this limit for stacked devices.

before:

$ cat /sys/block/nvme0n1/queue/max_discard_segments
256
$ cat /sys/block/dm-0/queue/max_discard_segments
1

after:

$ cat /sys/block/nvme0n1/queue/max_discard_segments
256
$ cat /sys/block/dm-0/queue/max_discard_segments
256

Fixes: 1e739730c5b9e ("block: optionally merge discontiguous discard bios into a single request")
Reviewed-by: Christoph Hellwig 
Signed-off-by: Mike Snitzer 
Signed-off-by: Jens Axboe 
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

partitions/aix: fix usage of uninitialized lv_info and lvname structures

2018-09-19T20:41:35+00:00

[ Upstream commit 14cb2c8a6c5dae57ee3e2da10fa3db2b9087e39e ]

The if-block that sets a successful return value in aix_partition()
uses 'lvip[].pps_per_lv' and 'n[].name' potentially uninitialized.

For example, if 'numlvs' is zero or alloc_lvn() fails, neither is
initialized, but are used anyway if alloc_pvd() succeeds after it.

So, make the alloc_pvd() call conditional on their initialization.

This has been hit when attaching an apparently corrupted/stressed
AIX LUN, misleading the kernel to pr_warn() invalid data and hang.

    [...] partition (null) (11 pp's found) is not contiguous
    [...] partition (null) (2 pp's found) is not contiguous
    [...] partition (null) (3 pp's found) is not contiguous
    [...] partition (null) (64 pp's found) is not contiguous

Fixes: 6ceea22bbbc8 ("partitions: add aix lvm partition support files")
Signed-off-by: Mauricio Faria de Oliveira 
Signed-off-by: Jens Axboe 
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

partitions/aix: append null character to print data from disk

2018-09-19T20:41:35+00:00

[ Upstream commit d43fdae7bac2def8c4314b5a49822cb7f08a45f1 ]

Even if properly initialized, the lvname array (i.e., strings)
is read from disk, and might contain corrupt data (e.g., lack
the null terminating character for strings).

So, make sure the partition name string used in pr_warn() has
the null terminating character.

Fixes: 6ceea22bbbc8 ("partitions: add aix lvm partition support files")
Suggested-by: Daniel J. Axtens 
Signed-off-by: Mauricio Faria de Oliveira 
Signed-off-by: Jens Axboe 
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

blk-mq: fix updating tags depth

2018-09-19T20:41:26+00:00

[ Upstream commit 75d6e175fc511e95ae3eb8f708680133bc211ed3 ]

The passed 'nr' from userspace represents the total depth, meantime
inside 'struct blk_mq_tags', 'nr_tags' stores the total tag depth,
and 'nr_reserved_tags' stores the reserved part.

There are two issues in blk_mq_tag_update_depth() now:

1) for growing tags, we should have used the passed 'nr', and keep the
number of reserved tags not changed.

2) the passed 'nr' should have been used for checking against
'tags->nr_tags', instead of number of the normal part.

This patch fixes the above two cases, and avoids kernel crash caused
by wrong resizing sbitmap queue.

Cc: "Ewan D. Milne" 
Cc: Christoph Hellwig 
Cc: Bart Van Assche 
Cc: Omar Sandoval 
Tested by: Marco Patalano 
Signed-off-by: Ming Lei 
Signed-off-by: Jens Axboe 
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

block: bfq: swap puts in bfqg_and_blkg_put

2018-09-19T20:41:20+00:00

commit d5274b3cd6a814ccb2f56d81ee87cbbf51bd4cf7 upstream.

Fix trivial use-after-free. This could be last reference to bfqg.

Fixes: 8f9bebc33dd7 ("block, bfq: access and cache blkg data only when safe")
Acked-by: Paolo Valente 
Signed-off-by: Konstantin Khlebnikov 
Signed-off-by: Jens Axboe 
Signed-off-by: Greg Kroah-Hartman