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Commit 0c0be98bbe67 ("md/raid10: prevent unnecessary calls to wake_up()
in fast path") missed one place, for example, with:
fio -direct=1 -rw=write/randwrite -iodepth=1 ...
Plug and unplug are called for each io, then wake_up() from raid10_unplug()
will cause lock contention as well.
Avoid this contention by using wake_up_barrier() instead of wake_up(),
where spin_lock is not held if waitqueue is empty.
Fio test script:
[global]
name=random reads and writes
ioengine=libaio
direct=1
readwrite=randrw
rwmixread=70
iodepth=64
buffered=0
filename=/dev/md0
size=1G
runtime=30
time_based
randrepeat=0
norandommap
refill_buffers
ramp_time=10
bs=4k
numjobs=400
group_reporting=1
[job1]
Test result with ramdisk raid10(By Ali):
Before this patch With this patch
READ IOPS=2033k IOPS=3642k
WRITE IOPS=871k IOPS=1561K
By the way, in this scenario, blk_plug_cb() will be allocated and freed
for each io, this seems need to be optimized as well.
Reported-and-tested-by: Ali Gholami Rudi <aligrudi@gmail.com>
Closes: https://lore.kernel.org/all/20231606122233@laper.mirepesht/
Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Signed-off-by: Song Liu <song@kernel.org>
Link: https://lore.kernel.org/r/20230621105728.1268542-1-yukuai1@huaweicloud.com
Commit 3ce94ce5d05a ("md: fix duplicate filename for rdev") introduce a
new lock 'delete_mutex', and trigger a new deadlock:
t1: remove rdev t2: sysfs writer
rdev_attr_store rdev_attr_store
mddev_lock
state_store
md_kick_rdev_from_array
lock delete_mutex
list_add mddev->deleting
unlock delete_mutex
mddev_unlock
mddev_lock
...
lock delete_mutex
kobject_del
// wait for sysfs writers to be done
mddev_unlock
lock delete_mutex
// wait for delete_mutex, deadlock
'delete_mutex' is used to protect the list 'mddev->deleting', turns out
that this list can be protected by 'reconfig_mutex' directly, and this
lock can be removed.
Fix this problem by removing the lock, and use 'reconfig_mutex' to
protect the list. mddev_unlock() will move this list to a local list to
be handled after 'reconfig_mutex' is dropped.
Fixes: 3ce94ce5d05a ("md: fix duplicate filename for rdev")
Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Signed-off-by: Song Liu <song@kernel.org>
Link: https://lore.kernel.org/r/20230621142933.1395629-1-yukuai1@huaweicloud.com
Following build error triggered while build with clang version 17.0.0
with W=1(this can't be reporduced with gcc 13.1.0):
drivers/md/raid1-10.c:117:25: error: casting from randomized structure
pointer type 'struct block_device *' to 'struct md_rdev *'
117 | struct md_rdev *rdev = (struct md_rdev *)bio->bi_bdev;
| ^
Fix this by casting 'bio->bi_bdev' to 'void *', as it used to be.
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202306142042.fmjfmTF8-lkp@intel.com/
Fixes: 8295efbe68c0 ("md/raid1-10: factor out a helper to submit normal write")
Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Signed-off-by: Song Liu <song@kernel.org>
Link: https://lore.kernel.org/r/20230616012136.3047071-1-yukuai1@huaweicloud.com
/sys/block/[device]/queue/iostats is used to control whether to count io
stat. Write 0 to it will clear queue_flags QUEUE_FLAG_IO_STAT which means
iostats is disabled. If we disable iostats and later endable it, the io
issued during this period will be counted incorrectly, inflight will be
decreased to -1.
//T1 set iostats
echo 0 > /sys/block/md0/queue/iostats
clear QUEUE_FLAG_IO_STAT
//T2 issue io
if (QUEUE_FLAG_IO_STAT) -> false
bio_start_io_acct
inflight++
echo 1 > /sys/block/md0/queue/iostats
set QUEUE_FLAG_IO_STAT
//T3 io end
if (QUEUE_FLAG_IO_STAT) -> true
bio_end_io_acct
inflight-- -> -1
Also, if iostats is enabled while issuing io but disabled while io end,
inflight will never be decreased.
Fix it by checking start_time when io end. If start_time is not 0, call
bio_end_io_acct().
Fixes: 528bc2cf2fcc ("md/raid10: enable io accounting")
Signed-off-by: Li Nan <linan122@huawei.com>
Signed-off-by: Song Liu <song@kernel.org>
Link: https://lore.kernel.org/r/20230609094320.2397604-1-linan666@huaweicloud.com
We get a kernel crash about "list_add corruption. next->prev should be
prev (ffff9c801bc01210), but was ffff9c77b688237c.
(next=ffffae586d8afe68)."
crash> struct list_head 0xffff9c801bc01210
struct list_head {
next = 0xffffae586d8afe68,
prev = 0xffffae586d8afe68
}
crash> struct list_head 0xffff9c77b688237c
struct list_head {
next = 0x0,
prev = 0x0
}
crash> struct list_head 0xffffae586d8afe68
struct list_head struct: invalid kernel virtual address: ffffae586d8afe68 type: "gdb_readmem_callback"
Cannot access memory at address 0xffffae586d8afe68
[230469.019492] Call Trace:
[230469.032041] prepare_to_wait+0x8a/0xb0
[230469.044363] ? bch_btree_keys_free+0x6c/0xc0 [escache]
[230469.056533] mca_cannibalize_lock+0x72/0x90 [escache]
[230469.068788] mca_alloc+0x2ae/0x450 [escache]
[230469.080790] bch_btree_node_get+0x136/0x2d0 [escache]
[230469.092681] bch_btree_check_thread+0x1e1/0x260 [escache]
[230469.104382] ? finish_wait+0x80/0x80
[230469.115884] ? bch_btree_check_recurse+0x1a0/0x1a0 [escache]
[230469.127259] kthread+0x112/0x130
[230469.138448] ? kthread_flush_work_fn+0x10/0x10
[230469.149477] ret_from_fork+0x35/0x40
bch_btree_check_thread() and bch_dirty_init_thread() may call
mca_cannibalize() to cannibalize other cached btree nodes. Only one thread
can do it at a time, so the op of other threads will be added to the
btree_cache_wait list.
We must call finish_wait() to remove op from btree_cache_wait before free
it's memory address. Otherwise, the list will be damaged. Also should call
bch_cannibalize_unlock() to release the btree_cache_alloc_lock and wake_up
other waiters.
Fixes: 8e7102273f59 ("bcache: make bch_btree_check() to be multithreaded")
Fixes: b144e45fc576 ("bcache: make bch_sectors_dirty_init() to be multithreaded")
Cc: stable@vger.kernel.org
Signed-off-by: Mingzhe Zou <mingzhe.zou@easystack.cn>
Signed-off-by: Coly Li <colyli@suse.de>
Link: https://lore.kernel.org/r/20230615121223.22502-7-colyli@suse.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
In some specific situations, the return value of __bch_btree_node_alloc
may be NULL. This may lead to a potential NULL pointer dereference in
caller function like a calling chain :
btree_split->bch_btree_node_alloc->__bch_btree_node_alloc.
Fix it by initializing the return value in __bch_btree_node_alloc.
Fixes: cafe56359144 ("bcache: A block layer cache")
Cc: stable@vger.kernel.org
Signed-off-by: Zheng Wang <zyytlz.wz@163.com>
Signed-off-by: Coly Li <colyli@suse.de>
Link: https://lore.kernel.org/r/20230615121223.22502-6-colyli@suse.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Due to the previous fix of __bch_btree_node_alloc, the return value will
never be a NULL pointer. So IS_ERR is enough to handle the failure
situation. Fix it by replacing IS_ERR_OR_NULL check by an IS_ERR check.
Fixes: cafe56359144 ("bcache: A block layer cache")
Cc: stable@vger.kernel.org
Signed-off-by: Zheng Wang <zyytlz.wz@163.com>
Signed-off-by: Coly Li <colyli@suse.de>
Link: https://lore.kernel.org/r/20230615121223.22502-5-colyli@suse.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
The cache_readaheads stat counter is not used anymore and should be
removed.
Signed-off-by: Andrea Tomassetti <andrea.tomassetti-opensource@devo.com>
Signed-off-by: Coly Li <colyli@suse.de>
Link: https://lore.kernel.org/r/20230615121223.22502-4-colyli@suse.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Since commit ee6d3dd4ed48 ("driver core: make kobj_type constant.")
the driver core allows the usage of const struct kobj_type.
Take advantage of this to constify the structure definitions to prevent
modification at runtime.
Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Signed-off-by: Coly Li <colyli@suse.de>
Link: https://lore.kernel.org/r/20230615121223.22502-3-colyli@suse.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Follow the advice of the Documentation/filesystems/sysfs.rst and show()
should only use sysfs_emit() or sysfs_emit_at() when formatting the
value to be returned to user space.
Signed-off-by: ye xingchen <ye.xingchen@zte.com.cn>
Signed-off-by: Coly Li <colyli@suse.de>
Link: https://lore.kernel.org/r/20230615121223.22502-2-colyli@suse.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
bio can be added to plug infinitely, and following writeback test can
trigger huge amount of plugged bio:
Test script:
modprobe brd rd_nr=4 rd_size=10485760
mdadm -CR /dev/md0 -l10 -n4 /dev/ram[0123] --assume-clean --bitmap=internal
echo 0 > /proc/sys/vm/dirty_background_ratio
fio -filename=/dev/md0 -ioengine=libaio -rw=write -bs=4k -numjobs=1 -iodepth=128 -name=test
Test result:
Monitor /sys/block/md0/inflight will found that inflight keep increasing
until fio finish writing, after running for about 2 minutes:
[root@fedora ~]# cat /sys/block/md0/inflight
0 4474191
Fix the problem by limiting the number of plugged bio based on the number
of copies for original bio.
Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Signed-off-by: Song Liu <song@kernel.org>
Link: https://lore.kernel.org/r/20230529131106.2123367-8-yukuai1@huaweicloud.com
current->bio_list will be set under submit_bio() context, in this case
bitmap io will be added to the list and wait for current io submission to
finish, while current io submission must wait for bitmap io to be done.
commit 874807a83139 ("md/raid1{,0}: fix deadlock in bitmap_unplug.") fix
the deadlock by handling plugged bio by daemon thread.
On the one hand, the deadlock won't exist after commit a214b949d8e3
("blk-mq: only flush requests from the plug in blk_mq_submit_bio"). On
the other hand, current solution makes it impossible to flush plugged bio
in raid1/10_make_request(), because this will cause that all the writes
will goto daemon thread.
In order to limit the number of plugged bio, commit 874807a83139
("md/raid1{,0}: fix deadlock in bitmap_unplug.") is reverted, and the
deadlock is fixed by handling bitmap io asynchronously.
Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Signed-off-by: Song Liu <song@kernel.org>
Link: https://lore.kernel.org/r/20230529131106.2123367-7-yukuai1@huaweicloud.com
If bitmap is enabled, bitmap must update before submitting write io, this
is why unplug callback must move these io to 'conf->pending_io_list' if
'current->bio_list' is not empty, which will suffer performance
degradation.
A new helper md_bitmap_unplug_async() is introduced to submit bitmap io
in a kworker, so that submit bitmap io in raid10_unplug() doesn't require
that 'current->bio_list' is empty.
This patch prepare to limit the number of plugged bio.
Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Signed-off-by: Song Liu <song@kernel.org>
Link: https://lore.kernel.org/r/20230529131106.2123367-6-yukuai1@huaweicloud.com
Commit 6cce3b23f6f8 ("[PATCH] md: write intent bitmap support for raid10")
add bitmap support, and it changed that write io is submitted through
daemon thread because bitmap need to be updated before write io. And
later, plug is used to fix performance regression because all the write io
will go to demon thread, which means io can't be issued concurrently.
However, if bitmap is not enabled, the write io should not go to daemon
thread in the first place, and plug is not needed as well.
Fixes: 6cce3b23f6f8 ("[PATCH] md: write intent bitmap support for raid10")
Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Signed-off-by: Song Liu <song@kernel.org>
Link: https://lore.kernel.org/r/20230529131106.2123367-5-yukuai1@huaweicloud.com
There are multiple places to do the same thing, factor out a helper to
prevent redundant code, and the helper will be used in following patch
as well.
Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Signed-off-by: Song Liu <song@kernel.org>
Link: https://lore.kernel.org/r/20230529131106.2123367-4-yukuai1@huaweicloud.com
Currently, there is no limit for raid1/raid10 plugged bio. While flushing
writes, raid1 has cond_resched() while raid10 doesn't, and too many
writes can cause soft lockup.
Follow up soft lockup can be triggered easily with writeback test for
raid10 with ramdisks:
watchdog: BUG: soft lockup - CPU#10 stuck for 27s! [md0_raid10:1293]
Call Trace:
<TASK>
call_rcu+0x16/0x20
put_object+0x41/0x80
__delete_object+0x50/0x90
delete_object_full+0x2b/0x40
kmemleak_free+0x46/0xa0
slab_free_freelist_hook.constprop.0+0xed/0x1a0
kmem_cache_free+0xfd/0x300
mempool_free_slab+0x1f/0x30
mempool_free+0x3a/0x100
bio_free+0x59/0x80
bio_put+0xcf/0x2c0
free_r10bio+0xbf/0xf0
raid_end_bio_io+0x78/0xb0
one_write_done+0x8a/0xa0
raid10_end_write_request+0x1b4/0x430
bio_endio+0x175/0x320
brd_submit_bio+0x3b9/0x9b7 [brd]
__submit_bio+0x69/0xe0
submit_bio_noacct_nocheck+0x1e6/0x5a0
submit_bio_noacct+0x38c/0x7e0
flush_pending_writes+0xf0/0x240
raid10d+0xac/0x1ed0
Fix the problem by adding cond_resched() to raid10 like what raid1 did.
Note that unlimited plugged bio still need to be optimized, for example,
in the case of lots of dirty pages writeback, this will take lots of
memory and io will spend a long time in plug, hence io latency is bad.
Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Signed-off-by: Song Liu <song@kernel.org>
Link: https://lore.kernel.org/r/20230529131106.2123367-2-yukuai1@huaweicloud.com
When removing a disk with replacement, the replacement will be used to
replace rdev. During this process, there is a brief window in which both
rdev and replacement are read as NULL in raid10_write_request(). This
will result in io not being submitted but it should be.
//remove //write
raid10_remove_disk raid10_write_request
mirror->rdev = NULL
read rdev -> NULL
mirror->rdev = mirror->replacement
mirror->replacement = NULL
read replacement -> NULL
Fix it by reading replacement first and rdev later, meanwhile, use smp_mb()
to prevent memory reordering.
Fixes: 475b0321a4df ("md/raid10: writes should get directed to replacement as well as original.")
Signed-off-by: Li Nan <linan122@huawei.com>
Reviewed-by: Yu Kuai <yukuai3@huawei.com>
Signed-off-by: Song Liu <song@kernel.org>
Link: https://lore.kernel.org/r/20230602091839.743798-3-linan666@huaweicloud.com
In raid10_sync_request(), if data cannot be read from any disk for
recovery, it will go to 'giveup' and let 'chunks_skipped' + 1. After
multiple 'giveup', when 'chunks_skipped >= geo.raid_disks', it will
return 'max_sector', indicating that the recovery has been completed.
However, the recovery is just aborted and the data remains inconsistent.
Fix it by setting mirror->recovery_disabled, which will prevent the spare
disk from being added to this mirror. The same issue also exists during
resync, it will be fixed afterwards.
Signed-off-by: Li Nan <linan122@huawei.com>
Signed-off-by: Song Liu <song@kernel.org>
Link: https://lore.kernel.org/r/20230602091839.743798-2-linan666@huaweicloud.com
Commit 1a855a060665 ("md: fix bug with re-adding of partially recovered
device.") only add device which is set to In_sync. But it let devices
without metadata cannot be added when they should be.
Commit bf572541ab44 ("md: fix regression with re-adding devices to arrays
with no metadata") fix the above issue, it set device without metadata to
In_sync when add new disk.
However, after commit f466722ca614 ("md: Change handling of save_raid_disk
and metadata update during recovery.") deletes changes of the first patch,
setting In_sync for devcie without metadata is meanless because the flag
will be cleared soon and will not be used during this period. Clean it up.
Signed-off-by: Li Nan <linan122@huawei.com>
Reviewed-by: Yu Kuai <yukuai3@huawei.com>
Signed-off-by: Song Liu <song@kernel.org>
Link: https://lore.kernel.org/r/20230527101851.3266500-2-linan666@huaweicloud.com
When add a new disk to raid10, it will traverse conf->mirror from start
and find one of the following mirror to add:
1. mirror->rdev is set to WantReplacement and it have no replacement,
set new disk to mirror->replacement.
2. no mirror->rdev, set new disk to mirror->rdev.
There is a array as below (sda is set to WantReplacement):
Number Major Minor RaidDevice State
0 8 0 0 active sync set-A /dev/sda
- 0 0 1 removed
2 8 32 2 active sync set-A /dev/sdc
3 8 48 3 active sync set-B /dev/sdd
Use 'mdadm --add' to add a new disk to this array, the new disk will
become sda's replacement instead of add to removed position, which is
confusing for users. Meanwhile, after new disk recovery success, sda
will be set to Faulty.
Prioritize adding disk to 'removed' mirror is a better choice. In the
above scenario, the behavior is the same as before, except sda will not
be deleted. Before other disks are added, continued use sda is more
reliable.
Signed-off-by: Li Nan <linan122@huawei.com>
Signed-off-by: Song Liu <song@kernel.org>
Link: https://lore.kernel.org/r/20230527092007.3008856-1-linan666@huaweicloud.com
'need_recover' and 'mrdev' are equivalent in raid10_sync_request(), and
inc mrdev->nr_pending is unreasonable if don't need recovery. Replace
'need_recover' with 'mrdev', and only inc nr_pending when needed.
Signed-off-by: Li Nan <linan122@huawei.com>
Reviewed-by: Yu Kuai <yukuai3@huawei.com>
Signed-off-by: Song Liu <song@kernel.org>
Link: https://lore.kernel.org/r/20230527072218.2365857-3-linan666@huaweicloud.com
There are two check of 'mreplace' in raid10_sync_request(). In the first
check, 'need_replace' will be set and 'mreplace' will be used later if
no-Faulty 'mreplace' exists, In the second check, 'mreplace' will be
set to NULL if it is Faulty, but 'need_replace' will not be changed
accordingly. null-ptr-deref occurs if Faulty is set between two check.
Fix it by merging two checks into one. And replace 'need_replace' with
'mreplace' because their values are always the same.
Fixes: ee37d7314a32 ("md/raid10: Fix raid10 replace hang when new added disk faulty")
Signed-off-by: Li Nan <linan122@huawei.com>
Reviewed-by: Yu Kuai <yukuai3@huawei.com>
Signed-off-by: Song Liu <song@kernel.org>
Link: https://lore.kernel.org/r/20230527072218.2365857-2-linan666@huaweicloud.com
When recovery is interrupted (reboot, etc.) check for MD_RECOVERY_RUNNING
is not enough to tell recovery is in progress. Also check recovery_cp
before starting reshape.
Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Signed-off-by: Song Liu <song@kernel.org>
Link: https://lore.kernel.org/r/20230529133410.2125914-1-yukuai1@huaweicloud.com
Currently, there are many places that md_thread can be accessed without
protection, following are known scenarios that can cause
null-ptr-dereference or uaf:
1) sync_thread that is allocated and started from md_start_sync()
2) mddev->thread can be accessed directly from timeout_store() and
md_bitmap_daemon_work()
3) md_unregister_thread() from action_store().
Currently, a global spinlock 'pers_lock' is borrowed to protect
'mddev->thread' in some places, this problem can be fixed likewise,
however, use a global lock for all the cases is not good.
Fix this problem by protecting all md_thread with rcu.
Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Signed-off-by: Song Liu <song@kernel.org>
Link: https://lore.kernel.org/r/20230523021017.3048783-6-yukuai1@huaweicloud.com
Register/unregister 'mddev->thread' are both under 'reconfig_mutex',
however, some context didn't hold the mutex to access mddev->thread,
which can cause null-ptr-deference:
1) md_bitmap_daemon_work() can be called from md_check_recovery() where
'reconfig_mutex' is not held, deference 'mddev->thread' might cause
null-ptr-deference, because md_unregister_thread() reset the pointer
before stopping the thread.
2) timeout_store() access 'mddev->thread' multiple times,
null-ptr-deference can be triggered if 'mddev->thread' is reset in the
middle.
This patch factor out a helper to set timeout, the new helper always
check if 'mddev->thread' is null first, so that problem 1 can be fixed.
Now that this helper only access 'mddev->thread' once, but it's possible
that 'mddev->thread' can be freed while this helper is still in progress,
hence the problem is not fixed yet. Follow up patches will fix this by
protecting md_thread with rcu.
Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Signed-off-by: Song Liu <song@kernel.org>
Link: https://lore.kernel.org/r/20230523021017.3048783-5-yukuai1@huaweicloud.com
md_wakeup_thread() can handle the case that pass in md_thread is NULL,
the only difference is that md_wakeup_thread() will be called when
current timeout is 'MAX_SCHEDULE_TIMEOUT', this should not matter
because timeout_store() is not hot path, and the daemon process is
woke up more than demand from other context already.
Prepare to factor out a helper to set timeout.
Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Signed-off-by: Song Liu <song@kernel.org>
Link: https://lore.kernel.org/r/20230523021017.3048783-4-yukuai1@huaweicloud.com
md_wakeup_thread() can't wakeup md_thread->tsk if md_thread->run is
still in progress, and in some cases md_thread->tsk need to be woke up
directly, like md_set_readonly() and do_md_stop().
Commit 9dfbdafda3b3 ("md: unlock mddev before reap sync_thread in
action_store") introduce a new scenario where unregister sync_thread is
not protected by 'reconfig_mutex', this can cause null-ptr-deference in
theroy:
t1: md_set_readonly t2: action_store
md_unregister_thread
// 'reconfig_mutex' is not held
// 'reconfig_mutex' is held by caller
if (mddev->sync_thread)
thread = *threadp
*threadp = NULL
wake_up_process(mddev->sync_thread->tsk)
// null-ptr-deference
Fix this problem by factoring out a helper to wake up md_thread directly,
so that 'sync_thread' won't be accessed multiple times from the reader
side. This helper also prepare to protect md_thread with rcu.
Noted that later patches is going to fix that unregister sync_thread is
not protected by 'reconfig_mutex' from action_store().
Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Signed-off-by: Song Liu <song@kernel.org>
Link: https://lore.kernel.org/r/20230523021017.3048783-2-yukuai1@huaweicloud.com
Commit 5792a2856a63 ("[PATCH] md: avoid a deadlock when removing a device
from an md array via sysfs") delays the deletion of rdev, however, this
introduces a window that rdev can be added again while the deletion is
not done yet, and sysfs will complain about duplicate filename.
Follow up patches try to fix this problem by flushing workqueue, however,
flush_rdev_wq() is just dead code, the progress in
md_kick_rdev_from_array():
1) list_del_rcu(&rdev->same_set);
2) synchronize_rcu();
3) queue_work(md_rdev_misc_wq, &rdev->del_work);
So in flush_rdev_wq(), if rdev is found in the list, work_pending() can
never pass, in the meantime, if work is queued, then rdev can never be
found in the list.
flush_rdev_wq() can be replaced by flush_workqueue() directly, however,
this approach is not good:
- the workqueue is global, this synchronization for all raid disks is
not necessary.
- flush_workqueue can't be called under 'reconfig_mutex', there is still
a small window between flush_workqueue() and mddev_lock() that other
contexts can queue new work, hence the problem is not solved completely.
sysfs already has apis to support delete itself through writer, and
these apis, specifically sysfs_break/unbreak_active_protection(), is used
to support deleting rdev synchronously. Therefore, the above commit can be
reverted, and sysfs duplicate filename can be avoided.
A new mdadm regression test is proposed as well([1]).
[1] https://lore.kernel.org/linux-raid/20230428062845.1975462-1-yukuai1@huaweicloud.com/
Fixes: 5792a2856a63 ("[PATCH] md: avoid a deadlock when removing a device from an md array via sysfs")
Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Signed-off-by: Song Liu <song@kernel.org>
Link: https://lore.kernel.org/r/20230523012727.3042247-1-yukuai1@huaweicloud.com
There is no input check when echo md/max_read_errors and overflow might
occur. Add check of input number.
Fixes: 1e50915fe0bb ("raid: improve MD/raid10 handling of correctable read errors.")
Signed-off-by: Li Nan <linan122@huawei.com>
Reviewed-by: Yu Kuai <yukuai3@huawei.com>
Signed-off-by: Song Liu <song@kernel.org>
Link: https://lore.kernel.org/r/20230522072535.1523740-3-linan666@huaweicloud.com
There is no input check when echo md/safe_mode_delay in safe_delay_store().
And msec might also overflow when HZ < 1000 in safe_delay_show(), Fix it by
checking overflow in safe_delay_store() and use unsigned long conversion in
safe_delay_show().
Fixes: 72e02075a33f ("md: factor out parsing of fixed-point numbers")
Signed-off-by: Li Nan <linan122@huawei.com>
Signed-off-by: Song Liu <song@kernel.org>
Link: https://lore.kernel.org/r/20230522072535.1523740-2-linan666@huaweicloud.com
If reshape is in progress and io across reshape_position is issued, such
io will wait for reshape to make progress(see details in the case that
make_stripe_request() return STRIPE_SCHEDULE_AND_RETRY).
It has been reported several times that if system reboot while growing
raid5 to raid6, array assemble will hang infinitely([1, 2]). This is
because following deadlock is triggered:
1) a normal io is waiting for reshape to progress, this io can be from
system-udevd or mdadm.
2) while assemble, mdadm tries to suspend the array, hence
'reconfig_mutex' is held and mddev_suspend() must wait for normal io
to be done.
3) daemon thread can't start reshape because 'reconfig_mutex' can't be
held.
1) and 3) is unbreakable because they're foundation design. In order to
break 2), following is possible solutions that I can think of:
a) Let mddev_suspend() fail is not a good option, because this will
break many scenarios since mddev_suspend() doesn't fail before.
b) Fail the io that is waiting for reshape to make progress from
mddev_suspend().
c) Return false for the io that is waiting for reshape to make
progress from raid5_make_request(), and these io will wait for
suspend to be done in md_handle_request(), where 'active_io' is
not grabbed.
c) sounds better than b), however, b) is used because it's easy and
straightforward, and it's verified that mdadm can assemble in this case.
On the other hand, c) breaks the logic that mddev_suspend() will wait
for submitted io to be completely handled.
Fix the problem by checking reshape in mddev_suspend(), if reshape can't
make progress and there are still some io waiting for reshape, fail
those io.
[1] https://lore.kernel.org/all/CAFig2csUV2QiomUhj_t3dPOgV300dbQ6XtM9ygKPdXJFSH__Nw@mail.gmail.com/
[2] https://lore.kernel.org/all/CAO2ABipzbw6QL5eNa44CQHjiVa-LTvS696Mh9QaTw+qsUKFUCw@mail.gmail.com/
Reported-by: Jove <jovetoo@gmail.com>
Reported-by: David Gilmour <dgilmour76@gmail.com>
Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Signed-off-by: Song Liu <song@kernel.org>
Link: https://lore.kernel.org/r/20230512015610.821290-6-yukuai1@huaweicloud.com
If reshape is interrupted(for example, echo frozen to sync_action), then
rdev replacement can be set. It's safe because reshape is always prior to
resync in md_check_recovery(). However, if system reboots, then kernel will
complain cannot handle concurrent replacement and reshape and this array
is not able to assemble anymore.
Fix this problem by don't allow replacement until reshape is done.
Reported-by: Peter Neuwirth <reddunur@online.de>
Link: https://lore.kernel.org/linux-raid/e2f96772-bfbc-f43b-6da1-f520e5164536@online.de/
Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Signed-off-by: Song Liu <song@kernel.org>
Link: https://lore.kernel.org/r/20230512015610.821290-2-yukuai1@huaweicloud.com
If we write a large number to md/bitmap_set_bits, md_bitmap_checkpage()
will return -EINVAL because 'page >= bitmap->pages', but the return value
was not checked immediately in md_bitmap_get_counter() in order to set
*blocks value and slab-out-of-bounds occurs.
Move check of 'page >= bitmap->pages' to md_bitmap_get_counter() and
return directly if true.
Fixes: ef4256733506 ("md/bitmap: optimise scanning of empty bitmaps.")
Signed-off-by: Li Nan <linan122@huawei.com>
Reviewed-by: Yu Kuai <yukuai3@huawei.com>
Signed-off-by: Song Liu <song@kernel.org>
Link: https://lore.kernel.org/r/20230515134808.3936750-2-linan666@huaweicloud.com
The only overlap between the block open flags mapped into the fmode_t and
other uses of fmode_t are FMODE_READ and FMODE_WRITE. Define a new
blk_mode_t instead for use in blkdev_get_by_{dev,path}, ->open and
->ioctl and stop abusing fmode_t.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Jack Wang <jinpu.wang@ionos.com> [rnbd]
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Christian Brauner <brauner@kernel.org>
Link: https://lore.kernel.org/r/20230608110258.189493-28-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
The current interface for exclusive opens is rather confusing as it
requires both the FMODE_EXCL flag and a holder. Remove the need to pass
FMODE_EXCL and just key off the exclusive open off a non-NULL holder.
For blkdev_put this requires adding the holder argument, which provides
better debug checking that only the holder actually releases the hold,
but at the same time allows removing the now superfluous mode argument.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Acked-by: Christian Brauner <brauner@kernel.org>
Acked-by: David Sterba <dsterba@suse.com> [btrfs]
Acked-by: Jack Wang <jinpu.wang@ionos.com> [rnbd]
Link: https://lore.kernel.org/r/20230608110258.189493-16-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
sb is just an on-stack pointer that can easily be reused by other calls.
Switch to use the bcache-wide bcache_kobj instead as there is no need to
claim per-bcache device anyway.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Link: https://lore.kernel.org/r/20230608110258.189493-13-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
The mode argument to the ->release block_device_operation is never used,
so remove it.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Acked-by: Christian Brauner <brauner@kernel.org>
Acked-by: Jack Wang <jinpu.wang@ionos.com> [rnbd]
Link: https://lore.kernel.org/r/20230608110258.189493-10-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
->open is only called on the whole device. Make that explicit by
passing a gendisk instead of the block_device.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Acked-by: Christian Brauner <brauner@kernel.org>
Acked-by: Jack Wang <jinpu.wang@ionos.com> [rnbd]
Link: https://lore.kernel.org/r/20230608110258.189493-9-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
bdev_check_media_change should only ever be called for the whole device.
Pass a gendisk to make that explicit and rename the function to
disk_check_media_change.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Acked-by: Christian Brauner <brauner@kernel.org>
Link: https://lore.kernel.org/r/20230608110258.189493-8-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
early_lookup_bdev is supposed to only be called from the early boot
code, but dm_get_device calls it as a general fallback when lookup_bdev
fails, which is problematic because early_lookup_bdev bypasses all normal
path based permission checking, and might cause problems with certain
container environments renaming devices.
Switch to only call early_lookup_bdev when dm is built-in and the system
state in not running yet. This means it is still available when tables
are constructed by dm-init.c from the kernel command line, but not
otherwise.
Note that this strictly speaking changes the kernel ABI as the PARTUUID=
and PARTLABEL= style syntax is now not available during a running
systems. They never were intended for that, but this breaks things
we'll have to figure out a way to make them available again. But if
avoidable in any way I'd rather avoid that.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Mike Snitzer <snitzer@kernel.org>
Link: https://lore.kernel.org/r/20230531125535.676098-21-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Open code dm_get_dev_t in the only remaining caller, and propagate the
exact error code from lookup_bdev and early_lookup_bdev.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20230531125535.676098-20-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
dm_init_init is called from early boot code, and thus lookup_bdev
will never succeed. Just open code that call to early_lookup_bdev
instead.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Mike Snitzer <snitzer@kernel.org>
Link: https://lore.kernel.org/r/20230531125535.676098-19-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Use the block_device acquired in dm_get_device for the check instead
of doing an extra lookup.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Mike Snitzer <snitzer@kernel.org>
Link: https://lore.kernel.org/r/20230531125535.676098-18-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
name_to_dev_t has a very misleading name, that doesn't make clear
it should only be used by the early init code, and also has a bad
calling convention that doesn't allow returning different kinds of
errors. Rename it to early_lookup_bdev to make the use case clear,
and return an errno, where -EINVAL means the string could not be
parsed, and -ENODEV means it the string was valid, but there was
no device found for it.
Also stub out the whole call for !CONFIG_BLOCK as all the non-block
root cases are always covered in the caller.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20230531125535.676098-14-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
