linux/block, branch v4.19

block: don't deal with discard limit in blkdev_issue_discard()

2018-10-18T13:23:40Z

blk_queue_split() does respect this limit via bio splitting, so no need to do that in blkdev_issue_discard(), then we can align to normal bio submit(bio_add_page() & submit_bio()). More importantly, this patch fixes one issue introduced in a22c4d7e34402cc ("block: re-add discard_granularity and alignment checks"), in which zero discard bio may be generated in case of zero alignment. Fixes: a22c4d7e34402ccdf3 ("block: re-add discard_granularity and alignment checks") Cc: stable@vger.kernel.org Cc: Ming Lin Cc: Mike Snitzer Cc: Christoph Hellwig Cc: Xiao Ni Tested-by: Mariusz Dabrowski Signed-off-by: Ming Lei Signed-off-by: Jens Axboe

blk-wbt: wake up all when we scale up, not down

2018-10-11T19:31:28Z

Tetsuo brought to my attention that I screwed up the scale_up/scale_down helpers when I factored out the rq-qos code. We need to wake up all the waiters when we add slots for requests to make, not when we shrink the slots. Otherwise we'll end up things waiting forever. This was a mistake and simply puts everything back the way it was. cc: stable@vger.kernel.org Fixes: a79050434b45 ("blk-rq-qos: refactor out common elements of blk-wbt") eported-by: Tetsuo Handa Signed-off-by: Josef Bacik Signed-off-by: Jens Axboe

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

2018-09-27T19:12:44Z

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

block: fix deadline elevator drain for zoned block devices

2018-09-27T01:57:24Z

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

blk-mq: Allow blocking queue tag iter callbacks

2018-09-26T02:17:59Z

A recent commit runs tag iterator callbacks under the rcu read lock, but existing callbacks do not satisfy the non-blocking requirement. The commit intended to prevent an iterator from accessing a queue that's being modified. This patch fixes the original issue by taking a queue reference instead of reading it, which allows callbacks to make blocking calls. Fixes: f5bbbbe4d6357 ("blk-mq: sync the update nr_hw_queues with blk_mq_queue_tag_busy_iter") Acked-by: Jianchao Wang Signed-off-by: Keith Busch Signed-off-by: Jens Axboe

block: use nanosecond resolution for iostat

2018-09-22T02:26:59Z

Klaus Kusche reported that the I/O busy time in /proc/diskstats was not updating properly on 4.18. This is because we started using ktime to track elapsed time, and we convert nanoseconds to jiffies when we update the partition counter. However, this gets rounded down, so any I/Os that take less than a jiffy are not accounted for. Previously in this case, the value of jiffies would sometimes increment while we were doing I/O, so at least some I/Os were accounted for. Let's convert the stats to use nanoseconds internally. We still report milliseconds as before, now more accurately than ever. The value is still truncated to 32 bits for backwards compatibility. Fixes: 522a777566f5 ("block: consolidate struct request timestamp fields") Cc: stable@vger.kernel.org Reported-by: Klaus Kusche Signed-off-by: Omar Sandoval Signed-off-by: Jens Axboe

blk-cgroup: increase number of supported policies

2018-09-11T16:59:53Z

After merging the iolatency policy, we potentially now have 4 policies being registered, but only support 3. This causes one of them to fail loading. Takashi reports that BFQ no longer works for him, because it fails to load due to policy registration failure. Bump to 5 policies, and also add a warning for when we have exceeded the global amount. If we have to touch this again, we should switch to a dynamic scheme instead. Reported-by: Takashi Iwai Reviewed-by: Jeff Moyer Tested-by: Takashi Iwai Signed-off-by: Jens Axboe

block: bfq: swap puts in bfqg_and_blkg_put

2018-09-06T17:32:58Z

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

block: don't warn when doing fsync on read-only devices

2018-09-05T22:14:36Z

It is possible to call fsync on a read-only handle (for example, fsck.ext2 does it when doing read-only check), and this call results in kernel warning. The patch b089cfd95d32 ("block: don't warn for flush on read-only device") attempted to disable the warning, but it is buggy and it doesn't (op_is_flush tests flags, but bio_op strips off the flags). Signed-off-by: Mikulas Patocka Fixes: 721c7fc701c7 ("block: fail op_is_write() requests to read-only partitions") Cc: stable@vger.kernel.org # 4.18 Signed-off-by: Jens Axboe

blkcg: use tryget logic when associating a blkg with a bio

2018-08-31T20:48:58Z

There is a very small change a bio gets caught up in a really unfortunate race between a task migration, cgroup exiting, and itself trying to associate with a blkg. This is due to css offlining being performed after the css->refcnt is killed which triggers removal of blkgs that reach their blkg->refcnt of 0. To avoid this, association with a blkg should use tryget and fallback to using the root_blkg. Fixes: 08e18eab0c579 ("block: add bi_blkg to the bio for cgroups") Reviewed-by: Josef Bacik Signed-off-by: Dennis Zhou Cc: Jiufei Xue Cc: Joseph Qi Cc: Tejun Heo Cc: Josef Bacik Cc: Jens Axboe Signed-off-by: Jens Axboe