Currently, io_ticks is accounted based on sampling, specifically
update_io_ticks() will always account io_ticks by 1 jiffies from
bdev_start_io_acct()/blk_account_io_start(), and the result can be
inaccurate, for example(HZ is 250):
Test script:
fio -filename=/dev/sda -bs=4k -rw=write -direct=1 -name=test -thinktime=4ms
Test result: util is about 90%, while the disk is really idle.
This behaviour is introduced by commit 5b18b5a737 ("block: delete
part_round_stats and switch to less precise counting"), however, there
was a key point that is missed that this patch also improve performance
a lot:
Before the commit:
part_round_stats:
if (part->stamp != now)
stats |= 1;
part_in_flight()
-> there can be lots of task here in 1 jiffies.
part_round_stats_single()
__part_stat_add()
part->stamp = now;
After the commit:
update_io_ticks:
stamp = part->bd_stamp;
if (time_after(now, stamp))
if (try_cmpxchg())
__part_stat_add()
-> only one task can reach here in 1 jiffies.
Hence in order to account io_ticks precisely, we only need to know if
there are IO inflight at most once in one jiffies. Noted that for
rq-based device, iterating tags should not be used here because
'tags->lock' is grabbed in blk_mq_find_and_get_req(), hence
part_stat_lock_inc/dec() and part_in_flight() is used to trace inflight.
The additional overhead is quite little:
- per cpu add/dec for each IO for rq-based device;
- per cpu sum for each jiffies;
And it's verified by null-blk that there are no performance degration
under heavy IO pressure.
Fixes: 5b18b5a737 ("block: delete part_round_stats and switch to less precise counting")
Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Link: https://lore.kernel.org/r/20240509123717.3223892-2-yukuai1@huaweicloud.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
So that if caller didn't use plug, for example, __blkdev_direct_IO_simple()
and __blkdev_direct_IO_async(), block layer can still benefit from caching
nsec time in the plug.
Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Link: https://lore.kernel.org/r/20240509123825.3225207-1-yukuai1@huaweicloud.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
btree_iter is used in two ways: either allocated on the stack with a
fixed size MAX_BSETS, or from a mempool with a dynamic size based on the
specific cache set. Previously, the struct had a fixed-length array of
size MAX_BSETS which was indexed out-of-bounds for the dynamically-sized
iterators, which causes UBSAN to complain.
This patch uses the same approach as in bcachefs's sort_iter and splits
the iterator into a btree_iter with a flexible array member and a
btree_iter_stack which embeds a btree_iter as well as a fixed-length
data array.
Cc: stable@vger.kernel.org
Closes: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/2039368
Signed-off-by: Matthew Mirvish <matthew@mm12.xyz>
Signed-off-by: Coly Li <colyli@suse.de>
Link: https://lore.kernel.org/r/20240509011117.2697-3-colyli@suse.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
ida_alloc() and ida_free() should be preferred to the deprecated
ida_simple_get() and ida_simple_remove().
Note that the upper limit of ida_simple_get() is exclusive, but the one of
ida_alloc_max() is inclusive. So a -1 has been added when needed.
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Signed-off-by: Coly Li <colyli@suse.de>
Link: https://lore.kernel.org/r/20240509011117.2697-2-colyli@suse.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This reverts commit 3f9f231236.
Using 64bit for 'sync_io' is unnecessary from the gendisk side. This
overflow will not cause any functional impact, except for a UBSAN
warning. Solving this overflow requires introducing additional
calculations and checks which are not necessary. So just keep using
32bit for 'sync_io'.
Signed-off-by: Li Nan <linan122@huawei.com>
Link: https://lore.kernel.org/r/20240507023103.781816-1-linan666@huaweicloud.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Discards can access a significant capacity and take longer than the user
expected. A user may change their mind about wanting to run that command
and attempt to kill the process and do something else with their device.
But since the task is uninterruptable, they have to wait for it to
finish, which could be many hours.
Open code blkdev_issue_discard in the BLKDISCARD ioctl handler and check
for a fatal signal at each iteration so the user doesn't have to wait
for their regretted operation to complete naturally.
Heavily based on an earlier patch from Keith Busch.
Reported-by: Conrad Meyer <conradmeyer@meta.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20240506042027.2289826-7-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Add a helper to wait for an entire chain of bios to complete.
[hch: split from a larger patch, moved and changed the name now that it
is non-static]
Signed-off-by: Keith Busch <kbusch@kernel.org>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20240506042027.2289826-6-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Factor out a helper from __blkdev_issue_discard that chews off as much as
possible from a discard range and allocates a bio for it.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20240506042027.2289826-5-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This is basically blk_next_bio just with the bio allocation moved
to the caller to allow for more flexible bio handling in the caller.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20240506042027.2289826-4-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Most bio operations get basic sanity checking in submit_bio and anything
more complicated than that is done in the callers. Discards are a bit
different from that in that a lot of checking is done in
__blkdev_issue_discard, and the specific errnos for that are returned
to userspace. Move the checks that require specific errnos to the ioctl
handler instead, and just leave the basic sanity checking in submit_bio
for the other handlers. This introduces two changes in behavior:
1) the logical block size alignment check of the start and len is lost
for non-ioctl callers.
This matches what is done for other operations including reads and
writes. We should probably verify this for all bios, but for now
make discards match the normal flow.
2) for non-ioctl callers all errors are reported on I/O completion now
instead of synchronously. Callers in general mostly ignore or log
errors so this will actually simplify the code once cleaned up
Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20240506042027.2289826-3-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
We now set a default granularity in the queue limits API, so don't
bother with this extra check.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20240506042027.2289826-2-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Fix the cmdline parsing of the "blkdevparts=" parameter using strsep(),
which makes the code simpler.
Before commit 146afeb235 ("block: use strscpy() to instead of
strncpy()"), we used a strncpy() to copy a block device name and partition
names. The commit simply replaced a strncpy() and NULL termination with
a strscpy(). It did not update calculations of length passed to strscpy().
While the length passed to strncpy() is just a length of valid characters
without NULL termination ('\0'), strscpy() takes it as a length of the
destination buffer, including a NULL termination.
Since the source buffer is not necessarily NULL terminated, the current
code copies "length - 1" characters and puts a NULL character in the
destination buffer. It replaces the last character with NULL and breaks
the parsing.
As an example, that buffer will be passed to parse_parts() and breaks
parsing sub-partitions due to the missing ')' at the end, like the
following.
example (Check Point V-80 & OpenWrt):
- Linux Kernel 6.6
[ 0.000000] Kernel command line: console=ttyS0,115200 earlycon=uart8250,mmio32,0xf0512000 crashkernel=30M mvpp2x.queue_mode=1 blkdevparts=mmcblk1:48M@10M(kernel-1),1M(dtb-1),720M(rootfs-1),48M(kernel-2),1M(dtb-2),720M(rootfs-2),300M(default_sw),650M(logs),1M(preset_cfg),1M(adsl),-(storage) maxcpus=4
...
[ 0.884016] mmc1: new HS200 MMC card at address 0001
[ 0.889951] mmcblk1: mmc1:0001 004GA0 3.69 GiB
[ 0.895043] cmdline partition format is invalid.
[ 0.895704] mmcblk1: p1
[ 0.903447] mmcblk1boot0: mmc1:0001 004GA0 2.00 MiB
[ 0.908667] mmcblk1boot1: mmc1:0001 004GA0 2.00 MiB
[ 0.913765] mmcblk1rpmb: mmc1:0001 004GA0 512 KiB, chardev (248:0)
1. "48M@10M(kernel-1),..." is passed to strscpy() with length=17
from parse_parts()
2. strscpy() returns -E2BIG and the destination buffer has
"48M@10M(kernel-1\0"
3. "48M@10M(kernel-1\0" is passed to parse_subpart()
4. parse_subpart() fails to find ')' when parsing a partition name,
and returns error
- Linux Kernel 6.1
[ 0.000000] Kernel command line: console=ttyS0,115200 earlycon=uart8250,mmio32,0xf0512000 crashkernel=30M mvpp2x.queue_mode=1 blkdevparts=mmcblk1:48M@10M(kernel-1),1M(dtb-1),720M(rootfs-1),48M(kernel-2),1M(dtb-2),720M(rootfs-2),300M(default_sw),650M(logs),1M(preset_cfg),1M(adsl),-(storage) maxcpus=4
...
[ 0.953142] mmc1: new HS200 MMC card at address 0001
[ 0.959114] mmcblk1: mmc1:0001 004GA0 3.69 GiB
[ 0.964259] mmcblk1: p1(kernel-1) p2(dtb-1) p3(rootfs-1) p4(kernel-2) p5(dtb-2) 6(rootfs-2) p7(default_sw) p8(logs) p9(preset_cfg) p10(adsl) p11(storage)
[ 0.979174] mmcblk1boot0: mmc1:0001 004GA0 2.00 MiB
[ 0.984674] mmcblk1boot1: mmc1:0001 004GA0 2.00 MiB
[ 0.989926] mmcblk1rpmb: mmc1:0001 004GA0 512 KiB, chardev (248:0
By the way, strscpy() takes a length of destination buffer and it is
often confusing when copying characters with a specified length. Using
strsep() helps to separate the string by the specified character. Then,
we can use strscpy() naturally with the size of the destination buffer.
Separating the string on the fly is also useful to omit the redundant
string copy, reducing memory usage and improve the code readability.
Fixes: 146afeb235 ("block: use strscpy() to instead of strncpy()")
Suggested-by: Naohiro Aota <naota@elisp.net>
Signed-off-by: INAGAKI Hiroshi <musashino.open@gmail.com>
Reviewed-by: Daniel Golle <daniel@makrotopia.org>
Link: https://lore.kernel.org/r/20240421074005.565-1-musashino.open@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Add a helper to check if partition scanning is enabled instead of
open coding the check in a few places. This now always checks for
the hidden flag even if all but one of the callers are never reachable
for hidden gendisks.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20240502130033.1958492-2-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Is is reported that for dm-raid10, lvextend + lvchange --syncaction will
trigger following softlockup:
kernel:watchdog: BUG: soft lockup - CPU#3 stuck for 26s! [mdX_resync:6976]
CPU: 7 PID: 3588 Comm: mdX_resync Kdump: loaded Not tainted 6.9.0-rc4-next-20240419 #1
RIP: 0010:_raw_spin_unlock_irq+0x13/0x30
Call Trace:
<TASK>
md_bitmap_start_sync+0x6b/0xf0
raid10_sync_request+0x25c/0x1b40 [raid10]
md_do_sync+0x64b/0x1020
md_thread+0xa7/0x170
kthread+0xcf/0x100
ret_from_fork+0x30/0x50
ret_from_fork_asm+0x1a/0x30
And the detailed process is as follows:
md_do_sync
j = mddev->resync_min
while (j < max_sectors)
sectors = raid10_sync_request(mddev, j, &skipped)
if (!md_bitmap_start_sync(..., &sync_blocks))
// md_bitmap_start_sync set sync_blocks to 0
return sync_blocks + sectors_skippe;
// sectors = 0;
j += sectors;
// j never change
Root cause is that commit 301867b1c1 ("md/raid10: check
slab-out-of-bounds in md_bitmap_get_counter") return early from
md_bitmap_get_counter(), without setting returned blocks.
Fix this problem by always set returned blocks from
md_bitmap_get_counter"(), as it used to be.
Noted that this patch just fix the softlockup problem in kernel, the
case that bitmap size doesn't match array size still need to be fixed.
Fixes: 301867b1c1 ("md/raid10: check slab-out-of-bounds in md_bitmap_get_counter")
Reported-and-tested-by: Nigel Croxon <ncroxon@redhat.com>
Closes: https://lore.kernel.org/all/71ba5272-ab07-43ba-8232-d2da642acb4e@redhat.com/
Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Link: https://lore.kernel.org/r/20240422065824.2516-1-yukuai1@huaweicloud.com
Signed-off-by: Song Liu <song@kernel.org>
Define the code for checking conventional and sequential write required
zones suing the functions blk_revalidate_conv_zone() and
blk_revalidate_seq_zone() respectively. This simplifies the zone type
switch-case in blk_revalidate_zone_cb().
No functional changes.
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Link: https://lore.kernel.org/r/20240501110907.96950-15-dlemoal@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
When BIOs plugged in a zone write plug are aborted,
blk_zone_wplug_bio_io_error() clears the BIO BIO_ZONE_WRITE_PLUGGING
flag so that bio_io_error(bio) does not end up calling
blk_zone_write_plug_bio_endio() and we thus need to manually drop the
reference on the zone write plug held by the aborted BIO.
Move the call to disk_put_zone_wplug() that is alwasy following the call
to blk_zone_wplug_bio_io_error() inside that function to simplify the
code.
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20240501110907.96950-14-dlemoal@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
We already have the disk variable obtained from the bio when calling
disk_get_zone_wplug(). So use that variable instead of dereferencing the
bio bdev again for the disk argument of disk_get_zone_wplug().
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20240501110907.96950-13-dlemoal@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
blk_zone_complete_request() must be called to handle the completion of a
zone write request handled with zone write plugging. This function is
called from blk_complete_request(), blk_update_request() and also in
blk_mq_submit_bio() error path. Improve this by moving this function
call into blk_mq_finish_request() as all requests are processed with
this function when they complete as well as when they are freed without
being executed. This also improves blk_update_request() used by scsi
devices as these may repeatedly call this function to handle partial
completions.
To be consistent with this change, blk_zone_complete_request() is
renamed to blk_zone_finish_request() and
blk_zone_write_plug_complete_request() is renamed to
blk_zone_write_plug_finish_request().
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20240501110907.96950-12-dlemoal@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Improve blk_zone_write_plug_bio_merged() to check that we succefully get
a reference on the zone write plug of the merged BIO, as expected since
for a merge we already have at least one request and one BIO referencing
the zone write plug. Comments in this function are also improved to
better explain the references to the BIO zone write plug.
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20240501110907.96950-11-dlemoal@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Zone write plugging ignores empty (no data) flush operations but handles
flush BIOs that have data to ensure that the flush machinery generated
write is processed in order. However, the call to
blk_zone_write_plug_attempt_merge() which sets a request
RQF_ZONE_WRITE_PLUGGING flag is called after blk_insert_flush(), thus
missing indicating that a non empty flush request completion needs
handling by zone write plugging.
Fix this by moving the call to blk_zone_write_plug_attempt_merge()
before blk_insert_flush(). And while at it, rename that function as
blk_zone_write_plug_init_request() to be clear that it is not just about
merging plugged BIOs in the request. While at it, also add a WARN_ONCE()
check that the zone write plug for the request is not NULL.
Fixes: dd291d77cc ("block: Introduce zone write plugging")
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20240501110907.96950-10-dlemoal@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Make sure that a request bio is not NULL before trying to restore the
request start sector.
Reported-by: Yi Zhang <yi.zhang@redhat.com>
Fixes: 6f8fd758de ("block: Restore sector of flush requests")
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20240501110907.96950-9-dlemoal@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Large write BIOs that span a zone boundary are split in
blk_mq_submit_bio() before being passed to blk_zone_plug_bio() for zone
write plugging. Such split BIO will be chained with one fragment
targeting one zone and the remainder of the BIO targeting the next
zone. The two BIOs can be executed in parallel, without a predetermine
order relative to eachother and their completion may be reversed: the
remainder first completing and the first fragment then completing. In
such case, bio_endio() will not immediately execute
blk_zone_write_plug_bio_endio() for the parent BIO (the remainder of the
split BIO) as the BIOs are chained. blk_zone_write_plug_bio_endio() for
the parent BIO will be executed only once the first fragment completes.
In the case of a device with small zones and very large BIOs, uch
completion pattern can lead to disk_should_remove_zone_wplug() to return
true for the zone of the parent BIO when the parent BIO request
completes and blk_zone_write_plug_complete_request() is executed. This
triggers the removal of the zone write plug from the hash table using
disk_remove_zone_wplug(). With the zone write plug of the parent BIO
missing, the call to disk_get_zone_wplug() in
blk_zone_write_plug_bio_endio() returns NULL and triggers a warning.
This patterns can be recreated fairly easily using a scsi_debug device
with small zone and btrfs. E.g.
modprobe scsi_debug delay=0 dev_size_mb=1024 sector_size=4096 \
zbc=host-managed zone_cap_mb=3 zone_nr_conv=0 zone_size_mb=4
mkfs.btrfs -f -O zoned /dev/sda
mount -t btrfs /dev/sda /mnt
fio --name=wrtest --rw=randwrite --direct=1 --ioengine=libaio \
--bs=4k --iodepth=16 --size=1M --directory=/mnt --time_based \
--runtime=10
umount /dev/sda
Will result in the warning:
[ 29.035538] WARNING: CPU: 3 PID: 37 at block/blk-zoned.c:1207 blk_zone_write_plug_bio_endio+0xee/0x1e0
...
[ 29.058682] Call Trace:
[ 29.059095] <TASK>
[ 29.059473] ? __warn+0x80/0x120
[ 29.059983] ? blk_zone_write_plug_bio_endio+0xee/0x1e0
[ 29.060728] ? report_bug+0x160/0x190
[ 29.061283] ? handle_bug+0x36/0x70
[ 29.061830] ? exc_invalid_op+0x17/0x60
[ 29.062399] ? asm_exc_invalid_op+0x1a/0x20
[ 29.063025] ? blk_zone_write_plug_bio_endio+0xee/0x1e0
[ 29.063760] bio_endio+0xb7/0x150
[ 29.064280] btrfs_clone_write_end_io+0x2b/0x60 [btrfs]
[ 29.065049] blk_update_request+0x17c/0x500
[ 29.065666] scsi_end_request+0x27/0x1a0 [scsi_mod]
[ 29.066356] scsi_io_completion+0x5b/0x690 [scsi_mod]
[ 29.067077] blk_complete_reqs+0x3a/0x50
[ 29.067692] __do_softirq+0xcf/0x2b3
[ 29.068248] ? sort_range+0x20/0x20
[ 29.068791] run_ksoftirqd+0x1c/0x30
[ 29.069339] smpboot_thread_fn+0xcc/0x1b0
[ 29.069936] kthread+0xcf/0x100
[ 29.070438] ? kthread_complete_and_exit+0x20/0x20
[ 29.071314] ret_from_fork+0x31/0x50
[ 29.071873] ? kthread_complete_and_exit+0x20/0x20
[ 29.072563] ret_from_fork_asm+0x11/0x20
[ 29.073146] </TASK>
either when fio executes or when unmount is executed.
Fix this by modifying disk_should_remove_zone_wplug() to check that the
reference count to a zone write plug is not larger than 2, that is, that
the only references left on the zone are the caller held reference
(blk_zone_write_plug_complete_request()) and the initial extra reference
for the zone write plug taken when it was initialized (and that is
dropped when the zone write plug is removed from the hash table).
To be consistent with this change, make sure to drop the request or BIO
held reference to the zone write plug before calling
disk_zone_wplug_unplug_bio(). All references are also dropped using
disk_put_zone_wplug() instead of atomic_dec() to ensure that the zone
write plug is freed if it needs to be.
Comments are also improved to clarify zone write plugs reference
handling.
Reported-by: Shin'ichiro Kawasaki <shinichiro.kawasaki@wdc.com>
Fixes: dd291d77cc ("block: Introduce zone write plugging")
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Link: https://lore.kernel.org/r/20240501110907.96950-8-dlemoal@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Fix disk_remove_zone_wplug() to ensure that a zone write plug already
removed from a disk hash table of zone write plugs is not removed
again. Do this by checking the BLK_ZONE_WPLUG_UNHASHED flag of the plug
and calling hlist_del_init_rcu() only if the flag is not set.
Furthermore, since BIO completions can happen at any time, that is,
decrementing of the zone write plug reference count can happen at any
time, make sure to use disk_put_zone_wplug() instead of atomic_dec() to
ensure that the zone write plug is freed when its last reference is
dropped. In order to do this, disk_remove_zone_wplug() is moved after
the definition of disk_put_zone_wplug(). disk_should_remove_zone_wplug()
is moved as well to keep it together with disk_remove_zone_wplug().
To be consistent with this change, add a check in disk_put_zone_wplug()
to ensure that a zone write plug being freed was already removed from
the disk hash table.
Fixes: dd291d77cc ("block: Introduce zone write plugging")
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20240501110907.96950-7-dlemoal@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Since a zone write plug BIO work is a field of struct blk_zone_wplug, we
must ensure that a zone write plug is never freed when its BIO
submission work is queued or running. Do this by holding a reference on
the zone write plug when the submission work is scheduled for execution
with queue_work() and releasing the reference at the end of the
execution of the work function blk_zone_wplug_bio_work().
The helper function disk_zone_wplug_schedule_bio_work() is introduced to
get a reference on a zone write plug and queue its work. This helper is
used in disk_zone_wplug_unplug_bio() and disk_zone_wplug_handle_error().
Fixes: dd291d77cc ("block: Introduce zone write plugging")
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20240501110907.96950-6-dlemoal@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
When zone is reset or finished, disk_zone_wplug_set_wp_offset() is
called to update the zone write plug write pointer offset and to clear
the zone error state (BLK_ZONE_WPLUG_ERROR flag) if it is set.
However, this processing is missing dropping the reference to the zone
write plug that was taken in disk_zone_wplug_set_error() when the error
flag was first set. Furthermore, the error state handling must release
the zone write plug lock to first execute a report zones command. When
the report zone races with a reset or finish operation that clears the
error, we can end up decrementing the zone write plug reference count
twice: once in disk_zone_wplug_set_wp_offset() for the reset/finish
operation and one more time in disk_zone_wplugs_work() once
disk_zone_wplug_handle_error() completes.
Fix this by introducing disk_zone_wplug_clear_error() as the symmetric
function of disk_zone_wplug_set_error(). disk_zone_wplug_clear_error()
decrements the zone write plug reference count obtained in
disk_zone_wplug_set_error() only if the error handling has not started
yet, that is, only if disk_zone_wplugs_work() has not yet taken the zone
write plug off the error list. This ensure that either
disk_zone_wplug_clear_error() or disk_zone_wplugs_work() drop the zone
write plug reference count.
Fixes: dd291d77cc ("block: Introduce zone write plugging")
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20240501110907.96950-5-dlemoal@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
When revalidating the zones of a zoned block device,
blk_revalidate_zone_cb() must allocate a zone write plug for any
sequential write required zone that is not empty nor full. However, the
current code tests the latter case by comparing the zone write pointer
offset to the zone size instead of the zone capacity. Furthermore,
disk_get_and_lock_zone_wplug() is called with a sector argument equal to
the zone start instead of the current zone write pointer position.
This commit fixes both issues by calling disk_get_and_lock_zone_wplug()
for a zone that is not empty and with a write pointer offset lower than
the zone capacity and use the zone capacity sector as the sector
argument for disk_get_and_lock_zone_wplug().
Fixes: dd291d77cc ("block: Introduce zone write plugging")
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20240501110907.96950-4-dlemoal@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
For a device that has no limits for the maximum number of open and
active zones, we default to using the number of zones, limited to
BLK_ZONE_WPLUG_DEFAULT_POOL_SIZE (128), for the maximum number of open
zones indicated to the user. However, for a device that has conventional
zones and less zones than BLK_ZONE_WPLUG_DEFAULT_POOL_SIZE, we should
not account conventional zones and set the limit to the number of
sequential write required zones. Furthermore, for cases where the limit
is equal to the number of sequential write required zones, we can
advertize a limit of 0 to indicate "no limits".
Fix this by moving the zone write plug mempool resizing from
disk_revalidate_zone_resources() to disk_update_zone_resources() where
we can safely compute the number of conventional zones and update the
limits.
Fixes: 843283e96e ("block: Fake max open zones limit when there is no limit")
Reported-by: Shin'ichiro Kawasaki <shinichiro.kawasaki@wdc.com>
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20240501110907.96950-3-dlemoal@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Using targets such as dm-linear, a mapped device can be created to
contain only conventional zones. Such device should not be treated as
zoned as it does not contain any mandatory sequential write required
zone. Since such device can be randomly written, we can modify
dm_set_zones_restrictions() to set the mapped device zoned queue limit
to false to expose it as a regular block device. The function
dm_check_zoned() does this after counting the number of conventional
zones of the mapped device and comparing it to the total number of zones
reported. The special dm_check_zoned_cb() report zones callback function
is used to count conventional zones.
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Benjamin Marzinski <bmarzins@redhat.com>
Link: https://lore.kernel.org/r/20240501110907.96950-2-dlemoal@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
In __sbitmap_queue_get_batch(), map->word is read several times, and
update atomically using atomic_long_try_cmpxchg(). But the first two read
of map->word is not protected.
This patch moves the statement val = READ_ONCE(map->word) forward,
eliminating unprotected accesses to map->word within the function.
It is aimed at reducing the number of benign races reported by KCSAN in
order to focus future debugging effort on harmful races.
Signed-off-by: linke li <lilinke99@qq.com>
Link: https://lore.kernel.org/r/tencent_0B517C25E519D3D002194E8445E86C04AD0A@qq.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
When a mutex lock is not used any more, the function mutex_destroy
should be called to mark the mutex lock uninitialized.
Fixes: f2298c0403 ("null_blk: multi queue aware block test driver")
Signed-off-by: Zhu Yanjun <yanjun.zhu@linux.dev>
Link: https://lore.kernel.org/r/20240425171635.4227-1-yanjun.zhu@linux.dev
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Pull MD fixes from Song:
"These changes contain various fixes by Yu Kuai, Li Nan, and
Florian-Ewald Mueller."
* tag 'md-6.10-20240425' of https://git.kernel.org/pub/scm/linux/kernel/git/song/md:
md: don't account sync_io if iostats of the disk is disabled
md: Fix overflow in is_mddev_idle
md: add check for sleepers in md_wakeup_thread()
md/raid5: fix deadlock that raid5d() wait for itself to clear MD_SB_CHANGE_PENDING
Changhui reported a kernel crash when running this simple shell
reproducer:
# cd /sys/kernel/debug/block && find . -type f -exec grep -aH . {} \;
The above results in a NULL pointer dereference if a device does not have
a zone_wplugs_hash allocated.
To fix this, return early if we don't have a zone_wplugs_hash.
Reported-by: Changhui Zhong <czhong@redhat.com>
Fixes: a98b05b02f ("block: Replace zone_wlock debugfs entry with zone_wplugs entry")
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Link: https://lore.kernel.org/r/e5fec079dfca448cc21c425cfa5d7b291f5faa67.1714046443.git.johannes.thumshirn@wdc.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
A zone write plug BIO work function blk_zone_wplug_bio_work() calls
submit_bio_noacct_nocheck() to execute the next unplugged BIO. This
function may block. So executing zone plugs BIO works using the block
layer global kblockd workqueue can potentially lead to preformance or
latency issues as the number of concurrent work for a workqueue is
limited to WQ_DFL_ACTIVE (256).
1) For a system with a large number of zoned disks, issuing write
requests to otherwise unused zones may be delayed wiating for a work
thread to become available.
2) Requeue operations which use kblockd but are independent of zone
write plugging may alsoi end up being delayed.
To avoid these potential performance issues, create a workqueue per
zoned device to execute zone plugs BIO work. The workqueue max active
parameter is set to the maximum number of zone write plugs allocated
with the zone write plug mempool. This limit is equal to the maximum
number of open zones of the disk and defaults to 128 for disks that do
not have a limit on the number of open zones.
Fixes: dd291d77cc ("block: Introduce zone write plugging")
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20240420075811.1276893-3-dlemoal@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
These functions are defined in the mq-deadline.c file, but not called
elsewhere, so delete these unused functions.
block/mq-deadline.c:134:1: warning: unused function 'deadline_earlier_request'.
block/mq-deadline.c:148:1: warning: unused function 'deadline_latter_request'.
Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Closes: https://bugzilla.openanolis.cn/show_bug.cgi?id=8803
Signed-off-by: Jiapeng Chong <jiapeng.chong@linux.alibaba.com>
Link: https://lore.kernel.org/r/20240419025610.34298-1-jiapeng.chong@linux.alibaba.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
In null_zone_write, we do not need to first check if the target zone
condition is FULL, READONLY or OFFLINE: for theses conditions, the check
of the command sector against the zone write pointer will always result
in the command failing. Remove these checks.
We still however need to check that the target zone write pointer is not
invalid for zone append operations. To do so, add the macro
NULL_ZONE_INVALID_WP and use it in null_set_zone_cond() when changing a
zone to READONLY or OFFLINE condition.
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20240411085502.728558-4-dlemoal@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
For zoned null_blk devices setup without any limit on the maximum number
of open and active zones, there is no need to count the number of zones
that are implicitly open, explicitly open and closed. This is indicated
by the boolean field need_zone_res_mgmt of sturct nullb_device.
Modify the zone management functions null_reset_zone(),
null_finish_zone(), null_open_zone() and null_close_zone() to manage
the zone condition counters only if the device need_zone_res_mgmt field
is true. With this change, the function __null_close_zone() is removed
and integrated into the 2 caller sites directly, with the
null_close_imp_open_zone() call site greatly simplified as this function
closes zones that are known to be in the implicit open condition.
null_zone_write() is modified in a similar manner to do zone condition
accouting only when the device need_zone_res_mgmt field is true.
With these changes, the inline helpers null_lock_zone_res() and
null_unlock_zone_res() are removed and replaced with direct calls to
spin_lock()/spin_unlock().
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Link: https://lore.kernel.org/r/20240411085502.728558-3-dlemoal@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Modify the null_handle_flush() and null_handle_rq() functions to return
a blk_status_t instead of an errno to simplify the call sites of these
functions and to be consistant with other null_handle_xxx() functions.
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Nitesh Shetty <nj.shetty@samsung.com>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20240411085502.728558-2-dlemoal@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
With the block layer zone write plugging being automatically done for
any write operation to a zone of a zoned block device, a regular request
plugging handled through current->plug can only ever see at most a
single write request per zone. In such case, any potential reordering
of the plugged requests will be harmless. We can thus remove the special
casing for write operations to zones and have these requests plugged as
well. This allows removing the function blk_mq_plug and instead directly
using current->plug where needed.
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Tested-by: Hans Holmberg <hans.holmberg@wdc.com>
Tested-by: Dennis Maisenbacher <dennis.maisenbacher@wdc.com>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Link: https://lore.kernel.org/r/20240408014128.205141-29-dlemoal@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Now that zone block device write ordering control does not depend
anymore on mq-deadline and zone write locking, there is no need to force
select the mq-deadline scheduler when CONFIG_BLK_DEV_ZONED is enabled.
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Tested-by: Hans Holmberg <hans.holmberg@wdc.com>
Tested-by: Dennis Maisenbacher <dennis.maisenbacher@wdc.com>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Link: https://lore.kernel.org/r/20240408014128.205141-28-dlemoal@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Zone write locking is now unused and replaced with zone write plugging.
Remove all code that was implementing zone write locking, that is, the
various helper functions controlling request zone write locking and
the gendisk attached zone bitmaps.
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Tested-by: Hans Holmberg <hans.holmberg@wdc.com>
Tested-by: Dennis Maisenbacher <dennis.maisenbacher@wdc.com>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Link: https://lore.kernel.org/r/20240408014128.205141-27-dlemoal@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
In preparation to completely remove zone write locking, replace the
"zone_wlock" mq-debugfs entry that was listing zones that are
write-locked with the zone_wplugs entry which lists the zones that
currently have a write plug allocated.
The write plug information provided is: the zone number, the zone write
plug flags, the zone write plug write pointer offset and the number of
BIOs currently waiting for execution in the zone write plug BIO list.
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Tested-by: Hans Holmberg <hans.holmberg@wdc.com>
Tested-by: Dennis Maisenbacher <dennis.maisenbacher@wdc.com>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Link: https://lore.kernel.org/r/20240408014128.205141-26-dlemoal@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
block/blk-mq-debugfs-zone.c contains a single debugfs attribute
function. Defining this outside of block/blk-zoned.c does not really
help in any way, so move this zone related debugfs attribute to
block/blk-zoned.c and delete block/blk-mq-debugfs-zone.c.
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Tested-by: Hans Holmberg <hans.holmberg@wdc.com>
Tested-by: Dennis Maisenbacher <dennis.maisenbacher@wdc.com>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Link: https://lore.kernel.org/r/20240408014128.205141-25-dlemoal@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Zone append operations are only allowed to target sequential write
required zones. blk_check_zone_append() uses bio_zone_is_seq() to check
this. However, this check is not necessary because:
1) For NVMe ZNS namespace devices, only sequential write required zones
exist, making the zone type check useless.
2) For null_blk, the driver will fail the request anyway, thus notifying
the user that a conventional zone was targeted.
3) For all other zoned devices, zone append is now emulated using zone
write plugging, which checks that a zone append operation does not
target a conventional zone.
In preparation for the removal of zone write locking and its
conventional zone bitmap (used by bio_zone_is_seq()), remove the
bio_zone_is_seq() call from blk_check_zone_append().
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Tested-by: Hans Holmberg <hans.holmberg@wdc.com>
Tested-by: Dennis Maisenbacher <dennis.maisenbacher@wdc.com>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Link: https://lore.kernel.org/r/20240408014128.205141-24-dlemoal@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
The only elevator feature ever implemented is ELEVATOR_F_ZBD_SEQ_WRITE
for signaling that a scheduler implements zone write locking to tightly
control the dispatching order of write operations to zoned block
devices. With the removal of zone write locking support in mq-deadline
and the reliance of all block device drivers on the block layer zone
write plugging to control ordering of write operations to zones, the
elevator feature ELEVATOR_F_ZBD_SEQ_WRITE is completely unused.
Remove it, and also remove the now unused code for filtering the
possible schedulers for a block device based on required features.
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Tested-by: Hans Holmberg <hans.holmberg@wdc.com>
Tested-by: Dennis Maisenbacher <dennis.maisenbacher@wdc.com>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Link: https://lore.kernel.org/r/20240408014128.205141-23-dlemoal@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
With the block layer generic plugging of write operations for zoned
block devices, mq-deadline, or any other scheduler, can only ever
see at most one write operation per zone at any time. There is thus no
sequentiality requirements for these writes and thus no need to tightly
control the dispatching of write requests using zone write locking.
Remove all the code that implement this control in the mq-deadline
scheduler and remove advertizing support for the
ELEVATOR_F_ZBD_SEQ_WRITE elevator feature.
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Tested-by: Hans Holmberg <hans.holmberg@wdc.com>
Tested-by: Dennis Maisenbacher <dennis.maisenbacher@wdc.com>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Link: https://lore.kernel.org/r/20240408014128.205141-22-dlemoal@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
