linux.git/drivers/block/drbd/drbd_main.c, branch for-next

drbd: Remove unused conn_lowest_minor

2024-10-11T13:11:44+00:00

conn_lowest_minor() last use was removed by 2011 commit
69a227731a37 ("drbd: Pass a peer device to a number of fuctions")

Remove it.

Signed-off-by: Dr. David Alan Gilbert 
Link: https://lore.kernel.org/r/20241010204426.277535-1-linux@treblig.org
Reviewed-by: Christoph Hellwig 
Signed-off-by: Jens Axboe

drbd: Fix atomicity violation in drbd_uuid_set_bm()

2024-09-18T10:16:23+00:00

The violation of atomicity occurs when the drbd_uuid_set_bm function is
executed simultaneously with modifying the value of
device->ldev->md.uuid[UI_BITMAP]. Consider a scenario where, while
device->ldev->md.uuid[UI_BITMAP] passes the validity check when its
value is not zero, the value of device->ldev->md.uuid[UI_BITMAP] is
written to zero. In this case, the check in drbd_uuid_set_bm might refer
to the old value of device->ldev->md.uuid[UI_BITMAP] (before locking),
which allows an invalid value to pass the validity check, resulting in
inconsistency.

To address this issue, it is recommended to include the data validity
check within the locked section of the function. This modification
ensures that the value of device->ldev->md.uuid[UI_BITMAP] does not
change during the validation process, thereby maintaining its integrity.

This possible bug is found by an experimental static analysis tool
developed by our team. This tool analyzes the locking APIs to extract
function pairs that can be concurrently executed, and then analyzes the
instructions in the paired functions to identify possible concurrency
bugs including data races and atomicity violations.

Fixes: 9f2247bb9b75 ("drbd: Protect accesses to the uuid set with a spinlock")
Cc: stable@vger.kernel.org
Signed-off-by: Qiu-ji Chen 
Reviewed-by: Philipp Reisner 
Link: https://lore.kernel.org/r/20240913083504.10549-1-chenqiuji666@gmail.com
Signed-off-by: Jens Axboe

drbd: use sendpages_ok() instead of sendpage_ok()

2024-07-28T22:47:52+00:00

Currently _drbd_send_page() use sendpage_ok() in order to enable
MSG_SPLICE_PAGES, it check the first page of the iterator, the iterator
may represent contiguous pages.

MSG_SPLICE_PAGES enables skb_splice_from_iter() which checks all the
pages it sends with sendpage_ok().

When _drbd_send_page() sends an iterator that the first page is
sendable, but one of the other pages isn't skb_splice_from_iter() warns
and aborts the data transfer.

Using the new helper sendpages_ok() in order to enable MSG_SPLICE_PAGES
solves the issue.

Acked-by: Christoph Böhmwalder 
Signed-off-by: Ofir Gal 
Link: https://lore.kernel.org/r/20240718084515.3833733-4-ofir.gal@volumez.com
Signed-off-by: Jens Axboe

drbd: Add peer_device to Kernel doc

2024-07-23T13:31:38+00:00

Add missing documentation of peer_device parameter to Kernel doc.

These parameters were added in commit 8164dd6c8ae1 ("drbd: Add peer
device parameter to whole-bitmap I/O handlers")

Flagged by W=1 builds.

Signed-off-by: Simon Horman 
Link: https://lore.kernel.org/r/20240723-drbd-doc-v1-1-a04d9b7a9688@kernel.org
Signed-off-by: Jens Axboe

block: move the stable_writes flag to queue_limits

2024-06-19T13:58:28+00:00

Move the stable_writes flag into the queue_limits feature field so that
it can be set atomically with the queue frozen.

The flag is now inherited by blk_stack_limits, which greatly simplifies
the code in dm, and fixed md which previously did not pass on the flag
set on lower devices.

Signed-off-by: Christoph Hellwig 
Reviewed-by: Damien Le Moal 
Reviewed-by: Hannes Reinecke 
Link: https://lore.kernel.org/r/20240617060532.127975-18-hch@lst.de
Signed-off-by: Jens Axboe

block: move the nonrot flag to queue_limits

2024-06-19T13:58:28+00:00

Move the nonrot flag into the queue_limits feature field so that it can
be set atomically with the queue frozen.

Use the chance to switch to defaulting to non-rotational and require
the driver to opt into rotational, which matches the polarity of the
sysfs interface.

For the z2ram, ps3vram, 2x memstick, ubiblock and dcssblk the new
rotational flag is not set as they clearly are not rotational despite
this being a behavior change.  There are some other drivers that
unconditionally set the rotational flag to keep the existing behavior
as they arguably can be used on rotational devices even if that is
probably not their main use today (e.g. virtio_blk and drbd).

The flag is automatically inherited in blk_stack_limits matching the
existing behavior in dm and md.

Signed-off-by: Christoph Hellwig 
Reviewed-by: Damien Le Moal 
Reviewed-by: Hannes Reinecke 
Link: https://lore.kernel.org/r/20240617060532.127975-15-hch@lst.de
Signed-off-by: Jens Axboe

block: move cache control settings out of queue->flags

2024-06-19T13:58:28+00:00

Move the cache control settings into the queue_limits so that the flags
can be set atomically with the device queue frozen.

Add new features and flags field for the driver set flags, and internal
(usually sysfs-controlled) flags in the block layer.  Note that we'll
eventually remove enough field from queue_limits to bring it back to the
previous size.

The disable flag is inverted compared to the previous meaning, which
means it now survives a rescan, similar to the max_sectors and
max_discard_sectors user limits.

The FLUSH and FUA flags are now inherited by blk_stack_limits, which
simplified the code in dm a lot, but also causes a slight behavior
change in that dm-switch and dm-unstripe now advertise a write cache
despite setting num_flush_bios to 0.  The I/O path will handle this
gracefully, but as far as I can tell the lack of num_flush_bios
and thus flush support is a pre-existing data integrity bug in those
targets that really needs fixing, after which a non-zero num_flush_bios
should be required in dm for targets that map to underlying devices.

Signed-off-by: Christoph Hellwig 
Acked-by: Ulf Hansson 
Reviewed-by: Damien Le Moal 
Reviewed-by: Hannes Reinecke 
Link: https://lore.kernel.org/r/20240617060532.127975-14-hch@lst.de
Signed-off-by: Jens Axboe

drbd: pass the max_hw_sectors limit to blk_alloc_disk

2024-03-06T15:30:34+00:00

Pass a queue_limits structure with the max_hw_sectors limit to
blk_alloc_disk instead of updating the limit on the allocated gendisk.

Signed-off-by: Christoph Hellwig 
Link: https://lore.kernel.org/r/20240305134041.137006-2-hch@lst.de
Signed-off-by: Jens Axboe

block: pass a queue_limits argument to blk_alloc_disk

2024-02-19T23:58:23+00:00

Pass a queue_limits to blk_alloc_disk and apply it if non-NULL.  This
will allow allocating queues with valid queue limits instead of setting
the values one at a time later.

Also change blk_alloc_disk to return an ERR_PTR instead of just NULL
which can't distinguish errors.

Signed-off-by: Christoph Hellwig 
Reviewed-by: Dan Williams 
Reviewed-by: Himanshu Madhani 
Link: https://lore.kernel.org/r/20240215071055.2201424-2-hch@lst.de
Signed-off-by: Jens Axboe

drbd: swap bvec_set_page len and offset

2023-09-06T13:33:03+00:00

bvec_set_page has the following signature:

static inline void bvec_set_page(struct bio_vec *bv, struct page *page,
		unsigned int len, unsigned int offset)

However, the usage in DRBD swaps the len and offset parameters. This
leads to a bvec with length=0 instead of the intended length=4096, which
causes sock_sendmsg to return -EIO.

This leaves DRBD unable to transmit any pages and thus completely
broken.

Swapping the parameters fixes the regression.

Fixes: eeac7405c735 ("drbd: Use sendmsg(MSG_SPLICE_PAGES) rather than sendpage()")
Reported-by: Serguei Ivantsov 
Link: https://lore.kernel.org/regressions/CAKH+VT3YLmAn0Y8=q37UTDShqxDLsqPcQ4hBMzY7HPn7zNx+RQ@mail.gmail.com/
Cc: stable@vger.kernel.org
Signed-off-by: Christoph Böhmwalder 
Link: https://lore.kernel.org/r/20230906133034.948817-1-christoph.boehmwalder@linbit.com
Signed-off-by: Jens Axboe