linux-stable.git/drivers/md/dm.c, branch linux-6.2.y

dm: fix improper splitting for abnormal bios

2023-04-13T15:02:34+00:00

[ Upstream commit f7b58a69fad9d2c4c90cab0247811155dd0d48e7 ]

"Abnormal" bios include discards, write zeroes and secure erase. By no
longer passing the calculated 'len' pointer, commit 7dd06a2548b2 ("dm:
allow dm_accept_partial_bio() for dm_io without duplicate bios") took a
senseless approach to disallowing dm_accept_partial_bio() from working
for duplicate bios processed using __send_duplicate_bios().

It inadvertently and incorrectly stopped the use of 'len' when
initializing a target's io (in alloc_tio). As such the resulting tio
could address more area of a device than it should.

For example, when discarding an entire DM striped device with the
following DM table:
 vg-lvol0: 0 159744 striped 2 128 7:0 2048 7:1 2048
 vg-lvol0: 159744 45056 striped 2 128 7:2 2048 7:3 2048

Before this fix:

 device-mapper: striped: target_stripe=0, bdev=7:0, start=2048 len=102400
 blkdiscard: attempt to access beyond end of device
 loop0: rw=2051, sector=2048, nr_sectors = 102400 limit=81920

 device-mapper: striped: target_stripe=1, bdev=7:1, start=2048 len=102400
 blkdiscard: attempt to access beyond end of device
 loop1: rw=2051, sector=2048, nr_sectors = 102400 limit=81920

After this fix;

 device-mapper: striped: target_stripe=0, bdev=7:0, start=2048 len=79872
 device-mapper: striped: target_stripe=1, bdev=7:1, start=2048 len=79872

Fixes: 7dd06a2548b2 ("dm: allow dm_accept_partial_bio() for dm_io without duplicate bios")
Cc: stable@vger.kernel.org
Reported-by: Orange Kao 
Signed-off-by: Mike Snitzer 
Signed-off-by: Sasha Levin

dm: change "unsigned" to "unsigned int"

2023-04-13T15:02:34+00:00

[ Upstream commit 86a3238c7b9b759cb864f4f768ab2e24687dc0e6 ]

Signed-off-by: Heinz Mauelshagen 
Signed-off-by: Mike Snitzer 
Stable-dep-of: f7b58a69fad9 ("dm: fix improper splitting for abnormal bios")
Signed-off-by: Sasha Levin

dm: fix __send_duplicate_bios() to always allow for splitting IO

2023-04-06T10:12:42+00:00

commit 666eed46769d929c3e13636134ecfc67d75ef548 upstream.

Commit 7dd76d1feec70 ("dm: improve bio splitting and associated IO
accounting") only called setup_split_accounting() from
__send_duplicate_bios() if a single bio were being issued. But the case
where duplicate bios are issued must call it too.

Otherwise the bio won't be split and resubmitted (via recursion through
block core back to DM) to submit the later portions of a bio (which may
map to an entirely different target).

For example, when discarding an entire DM striped device with the
following DM table:
 vg-lvol0: 0 159744 striped 2 128 7:0 2048 7:1 2048
 vg-lvol0: 159744 45056 striped 2 128 7:2 2048 7:3 2048

Before (broken, discards the first striped target's devices twice):
 device-mapper: striped: target_stripe=0, bdev=7:0, start=2048 len=79872
 device-mapper: striped: target_stripe=1, bdev=7:1, start=2048 len=79872
 device-mapper: striped: target_stripe=0, bdev=7:0, start=2049 len=22528
 device-mapper: striped: target_stripe=1, bdev=7:1, start=2048 len=22528

After (works as expected):
 device-mapper: striped: target_stripe=0, bdev=7:0, start=2048 len=79872
 device-mapper: striped: target_stripe=1, bdev=7:1, start=2048 len=79872
 device-mapper: striped: target_stripe=0, bdev=7:2, start=2048 len=22528
 device-mapper: striped: target_stripe=1, bdev=7:3, start=2048 len=22528

Fixes: 7dd76d1feec70 ("dm: improve bio splitting and associated IO accounting")
Cc: stable@vger.kernel.org
Reported-by: Orange Kao 
Signed-off-by: Mike Snitzer 
Signed-off-by: Greg Kroah-Hartman

dm stats: check for and propagate alloc_percpu failure

2023-03-30T10:51:42+00:00

commit d3aa3e060c4a80827eb801fc448debc9daa7c46b upstream.

Check alloc_precpu()'s return value and return an error from
dm_stats_init() if it fails. Update alloc_dev() to fail if
dm_stats_init() does.

Otherwise, a NULL pointer dereference will occur in dm_stats_cleanup()
even if dm-stats isn't being actively used.

Fixes: fd2ed4d25270 ("dm: add statistics support")
Cc: stable@vger.kernel.org
Signed-off-by: Jiasheng Jiang 
Signed-off-by: Mike Snitzer 
Signed-off-by: Greg Kroah-Hartman

block: count 'ios' and 'sectors' when io is done for bio-based device

2023-03-22T12:37:50+00:00

[ Upstream commit 5f27571382ca42daa3e3d40d1b252bf18c2b61d2 ]

While using iostat for raid, I observed very strange 'await'
occasionally, and turns out it's due to that 'ios' and 'sectors' is
counted in bdev_start_io_acct(), while 'nsecs' is counted in
bdev_end_io_acct(). I'm not sure why they are ccounted like that
but I think this behaviour is obviously wrong because user will get
wrong disk stats.

Fix the problem by counting 'ios' and 'sectors' when io is done, like
what rq-based device does.

Fixes: 394ffa503bc4 ("blk: introduce generic io stat accounting help function")
Signed-off-by: Yu Kuai 
Reviewed-by: Christoph Hellwig 
Link: https://lore.kernel.org/r/20230223091226.1135678-1-yukuai1@huaweicloud.com
Signed-off-by: Jens Axboe 
Signed-off-by: Sasha Levin

dm: add cond_resched() to dm_wq_requeue_work()

2023-03-10T08:29:43+00:00

commit f77692d65d54665d81815349cc727baa85e8b71d upstream.

Otherwise the while() loop in dm_wq_requeue_work() can result in a
"dead loop" on systems that have preemption disabled. This is
particularly problematic on single cpu systems.

Fixes: 8b211aaccb915 ("dm: add two stage requeue mechanism")
Cc: stable@vger.kernel.org
Signed-off-by: Mike Snitzer 
Signed-off-by: Greg Kroah-Hartman

dm: add cond_resched() to dm_wq_work()

2023-03-10T08:29:43+00:00

commit 0ca44fcef241768fd25ee763b3d203b9852f269b upstream.

Otherwise the while() loop in dm_wq_work() can result in a "dead
loop" on systems that have preemption disabled. This is particularly
problematic on single cpu systems.

Cc: stable@vger.kernel.org
Signed-off-by: Pingfan Liu 
Acked-by: Ming Lei 
Signed-off-by: Mike Snitzer 
Signed-off-by: Greg Kroah-Hartman

dm: send just one event on resize, not two

2023-03-10T08:29:43+00:00

commit 7533afa1d27ba1234146d31d2402c195cf195962 upstream.

Device mapper sends an uevent when the device is suspended, using the
function set_capacity_and_notify. However, this causes a race condition
with udev.

Udev skips scanning dm devices that are suspended. If we send an uevent
while we are suspended, udev will be racing with device mapper resume
code. If the device mapper resume code wins the race, udev will process
the uevent after the device is resumed and it will properly scan the
device.

However, if udev wins the race, it will receive the uevent, find out that
the dm device is suspended and skip scanning the device. This causes bugs
such as systemd unmounting the device - see
https://bugzilla.redhat.com/show_bug.cgi?id=2158628

This commit fixes this race.

We replace the function set_capacity_and_notify with set_capacity, so that
the uevent is not sent at this point. In do_resume, we detect if the
capacity has changed and we pass a boolean variable need_resize_uevent to
dm_kobject_uevent. dm_kobject_uevent adds "RESIZE=1" to the uevent if
need_resize_uevent is set.

Signed-off-by: Mikulas Patocka 
Tested-by: Peter Rajnoha 
Cc: stable@vger.kernel.org
Signed-off-by: Mike Snitzer 
Signed-off-by: Greg Kroah-Hartman

dm: remove flush_scheduled_work() during local_exit()

2023-03-10T08:28:39+00:00

[ Upstream commit 0b22ff5360f5c4e11050b89206370fdf7dc0a226 ]

Commit acfe0ad74d2e1 ("dm: allocate a special workqueue for deferred
device removal") switched from using system workqueue to a single
workqueue local to DM.  But it didn't eliminate the call to
flush_scheduled_work() that was introduced purely for the benefit of
deferred device removal with commit 2c140a246dc ("dm: allow remove to
be deferred").

Since DM core uses its own workqueue (and queue_work) there is no need
to call flush_scheduled_work() from local_exit().  local_exit()'s
destroy_workqueue(deferred_remove_workqueue) handles flushing work
started with queue_work().

Fixes: acfe0ad74d2e1 ("dm: allocate a special workqueue for deferred device removal")
Signed-off-by: Mike Snitzer 
Signed-off-by: Sasha Levin

block: handle bio_split_to_limits() NULL return

2023-01-04T16:05:23+00:00

This can't happen right now, but in preparation for allowing
bio_split_to_limits() returning NULL if it ended the bio, check for it
in all the callers.

Signed-off-by: Jens Axboe