linux-stable.git/drivers/block/loop.c, branch v6.14.8

loop: Add sanity check for read/write_iter

2025-05-18T06:26:07+00:00

[ Upstream commit f5c84eff634ba003326aa034c414e2a9dcb7c6a7 ]

Some file systems do not support read_iter/write_iter, such as selinuxfs
in this issue.
So before calling them, first confirm that the interface is supported and
then call it.

It is releavant in that vfs_iter_read/write have the check, and removal
of their used caused szybot to be able to hit this issue.

Fixes: f2fed441c69b ("loop: stop using vfs_iter__{read,write} for buffered I/O")
Reported-by: syzbot+6af973a3b8dfd2faefdc@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=6af973a3b8dfd2faefdc
Signed-off-by: Lizhi Xu 
Reviewed-by: Christoph Hellwig 
Link: https://lore.kernel.org/r/20250428143626.3318717-1-lizhi.xu@windriver.com
Signed-off-by: Jens Axboe 
Signed-off-by: Sasha Levin

loop: factor out a loop_assign_backing_file helper

2025-05-18T06:26:07+00:00

[ Upstream commit d278164832618bf2775c6a89e6434e2633de1eed ]

Split the code for setting up a backing file into a helper in preparation
of adding more code to this path.

Signed-off-by: Christoph Hellwig 
Reviewed-by: Damien Le Moal 
Link: https://lore.kernel.org/r/20250131120120.1315125-2-hch@lst.de
Signed-off-by: Jens Axboe 
Stable-dep-of: f5c84eff634b ("loop: Add sanity check for read/write_iter")
Signed-off-by: Sasha Levin

loop: LOOP_SET_FD: send uevents for partitions

2025-04-25T08:51:05+00:00

commit 0dba7a05b9e47d8b546399117b0ddf2426dc6042 upstream.

Remove the suppression of the uevents before scanning for partitions.
The partitions inherit their suppression settings from their parent device,
which lead to the uevents being dropped.

This is similar to the same changes for LOOP_CONFIGURE done in
commit bb430b694226 ("loop: LOOP_CONFIGURE: send uevents for partitions").

Fixes: 498ef5c777d9 ("loop: suppress uevents while reconfiguring the device")
Cc: stable@vger.kernel.org
Signed-off-by: Thomas Weißschuh 
Reviewed-by: Jan Kara 
Link: https://lore.kernel.org/r/20250415-loop-uevent-changed-v3-1-60ff69ac6088@linutronix.de
Signed-off-by: Jens Axboe 
Signed-off-by: Greg Kroah-Hartman

loop: properly send KOBJ_CHANGED uevent for disk device

2025-04-25T08:51:05+00:00

commit e7bc0010ceb403d025100698586c8e760921d471 upstream.

The original commit message and the wording "uncork" in the code comment
indicate that it is expected that the suppressed event instances are
automatically sent after unsuppressing.
This is not the case, instead they are discarded.
In effect this means that no "changed" events are emitted on the device
itself by default.
While each discovered partition does trigger a changed event on the
device, devices without partitions don't have any event emitted.

This makes udev miss the device creation and prompted workarounds in
userspace. See the linked util-linux/losetup bug.

Explicitly emit the events and drop the confusingly worded comments.

Link: https://github.com/util-linux/util-linux/issues/2434
Fixes: 498ef5c777d9 ("loop: suppress uevents while reconfiguring the device")
Cc: stable@vger.kernel.org
Signed-off-by: Thomas Weißschuh 
Link: https://lore.kernel.org/r/20250415-loop-uevent-changed-v2-1-0c4e6a923b2a@linutronix.de
Signed-off-by: Jens Axboe 
Signed-off-by: Greg Kroah-Hartman

loop: stop using vfs_iter_{read,write} for buffered I/O

2025-04-25T08:50:54+00:00

[ Upstream commit f2fed441c69b9237760840a45a004730ff324faf ]

vfs_iter_{read,write} always perform direct I/O when the file has the
O_DIRECT flag set, which breaks disabling direct I/O using the
LOOP_SET_STATUS / LOOP_SET_STATUS64 ioctls.

This was recenly reported as a regression, but as far as I can tell
was only uncovered by better checking for block sizes and has been
around since the direct I/O support was added.

Fix this by using the existing aio code that calls the raw read/write
iter methods instead.  Note that despite the comments there is no need
for block drivers to ever call flush_dcache_page themselves, and the
call is a left-over from prehistoric times.

Fixes: ab1cb278bc70 ("block: loop: introduce ioctl command of LOOP_SET_DIRECT_IO")
Reported-by: Darrick J. Wong 
Signed-off-by: Christoph Hellwig 
Reviewed-by: Ming Lei 
Tested-by: Darrick J. Wong 
Link: https://lore.kernel.org/r/20250409130940.3685677-1-hch@lst.de
Signed-off-by: Jens Axboe 
Signed-off-by: Sasha Levin

loop: aio inherit the ioprio of original request

2025-04-25T08:50:54+00:00

[ Upstream commit 1fdb8188c3d505452b40cdb365b1bb32be533a8e ]

Set cmd->iocb.ki_ioprio to the ioprio of loop device's request.
The purpose is to inherit the original request ioprio in the aio
flow.

Signed-off-by: Yunlong Xing 
Signed-off-by: Zhiguo Niu 
Reviewed-by: Christoph Hellwig 
Link: https://lore.kernel.org/r/20250414030159.501180-1-yunlong.xing@unisoc.com
Signed-off-by: Jens Axboe 
Stable-dep-of: f2fed441c69b ("loop: stop using vfs_iter_{read,write} for buffered I/O")
Signed-off-by: Sasha Levin

block: force noio scope in blk_mq_freeze_queue

2025-01-31T14:20:08+00:00

When block drivers or the core block code perform allocations with a
frozen queue, this could try to recurse into the block device to
reclaim memory and deadlock.  Thus all allocations done by a process
that froze a queue need to be done without __GFP_IO and __GFP_FS.
Instead of tying to track all of them down, force a noio scope as
part of freezing the queue.

Note that nvme is a bit of a mess here due to the non-owner freezes,
and they will be addressed separately.

Signed-off-by: Christoph Hellwig 
Link: https://lore.kernel.org/r/20250131120352.1315351-2-hch@lst.de
Signed-off-by: Jens Axboe

loop: don't clear LO_FLAGS_PARTSCAN on LOOP_SET_STATUS{,64}

2025-01-27T16:06:26+00:00

LOOP_SET_STATUS{,64} can set a lot more flags than it is supposed to
clear (the LOOP_SET_STATUS_CLEARABLE_FLAGS vs
LOOP_SET_STATUS_SETTABLE_FLAGS defines should have been a hint..).

Fix this by only clearing the bits in LOOP_SET_STATUS_CLEARABLE_FLAGS.

Fixes: ae074d07a0e5 ("loop: move updating lo_flag s out of loop_set_status_from_info")
Reported-by: kernel test robot 
Signed-off-by: Christoph Hellwig 
Link: https://lore.kernel.org/r/20250127143045.538279-1-hch@lst.de
Signed-off-by: Jens Axboe

loop: remove the use_dio field in struct loop_device

2025-01-10T14:31:50+00:00

This field duplicate the LO_FLAGS_DIRECT_IO flag in lo_flags.  Remove it
to have a single source of truth about using direct I/O.

Signed-off-by: Christoph Hellwig 
Link: https://lore.kernel.org/r/20250110073750.1582447-9-hch@lst.de
Signed-off-by: Jens Axboe

loop: don't freeze the queue in loop_update_dio

2025-01-10T14:31:50+00:00

All callers of loop_update_dio except for loop_configure already have the
queue frozen, and loop_configure works on an unbound device.  Remove the
superfluous recursive freezing in loop_update_dio and add asserts for the
locking and freezing state instead.

Signed-off-by: Christoph Hellwig 
Link: https://lore.kernel.org/r/20250110073750.1582447-8-hch@lst.de
Signed-off-by: Jens Axboe