linux-stable.git/drivers/block/loop.c, branch v6.12.35

loop: add file_start_write() and file_end_write()

2025-06-19T13:32:14+00:00

[ Upstream commit 39d86db34e41b96bd86f1955cd0ce6cd9c5fca4c ]

file_start_write() and file_end_write() should be added around ->write_iter().

Recently we switch to ->write_iter() from vfs_iter_write(), and the
implied file_start_write() and file_end_write() are lost.

Also we never add them for dio code path, so add them back for covering
both.

Cc: Jeff Moyer 
Fixes: f2fed441c69b ("loop: stop using vfs_iter_{read,write} for buffered I/O")
Fixes: bc07c10a3603 ("block: loop: support DIO & AIO")
Signed-off-by: Ming Lei 
Link: https://lore.kernel.org/r/20250527153405.837216-1-ming.lei@redhat.com
Signed-off-by: Jens Axboe 
Signed-off-by: Sasha Levin

loop: don't require ->write_iter for writable files in loop_configure

2025-05-29T09:03:17+00:00

[ Upstream commit 355341e4359b2d5edf0ed5e117f7e9e7a0a5dac0 ]

Block devices can be opened read-write even if they can't be written to
for historic reasons.  Remove the check requiring file->f_op->write_iter
when the block devices was opened in loop_configure. The call to
loop_check_backing_file just below ensures the ->write_iter is present
for backing files opened for writing, which is the only check that is
actually needed.

Fixes: f5c84eff634b ("loop: Add sanity check for read/write_iter")
Reported-by: Christian Hesse 
Signed-off-by: Christoph Hellwig 
Link: https://lore.kernel.org/r/20250520135420.1177312-1-hch@lst.de
Signed-off-by: Jens Axboe 
Signed-off-by: Sasha Levin

loop: check in LO_FLAGS_DIRECT_IO in loop_default_blocksize

2025-05-29T09:02:39+00:00

[ Upstream commit f6f9e32fe1e454ae8ac0190b2c2bd6074914beec ]

We can't go below the minimum direct I/O size no matter if direct I/O is
enabled by passing in an O_DIRECT file descriptor or due to the explicit
flag.  Now that LO_FLAGS_DIRECT_IO is set earlier after assigning a
backing file, loop_default_blocksize can check it instead of the
O_DIRECT flag to handle both conditions.

Signed-off-by: Christoph Hellwig 
Reviewed-by: Damien Le Moal 
Link: https://lore.kernel.org/r/20250131120120.1315125-4-hch@lst.de
Signed-off-by: Jens Axboe 
Signed-off-by: Sasha Levin

loop: Add sanity check for read/write_iter

2025-05-18T06:24:56+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

2025-05-18T06:24:56+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: refactor queue limits updates

2025-05-18T06:24:56+00:00

[ Upstream commit b38c8be255e89ffcdeb817407222d2de0b573a41 ]

Replace loop_reconfigure_limits with a slightly less encompassing
loop_update_limits that expects the caller to acquire and commit the
queue limits to prepare for sorting out the freeze vs limits lock
ordering.

Signed-off-by: Christoph Hellwig 
Reviewed-by: Ming Lei 
Reviewed-by: Damien Le Moal 
Reviewed-by: Martin K. Petersen 
Reviewed-by: Johannes Thumshirn 
Reviewed-by: Nilay Shroff 
Link: https://lore.kernel.org/r/20250110054726.1499538-11-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: Fix ABBA locking race

2025-05-18T06:24:56+00:00

[ Upstream commit b49125574cae26458d4aa02ce8f4523ba9a2a328 ]

Current loop calls vfs_statfs() while holding the q->limits_lock. If
FS takes some locking in vfs_statfs callback, this may lead to ABBA
locking bug (at least, FAT fs has this issue actually).

So this patch calls vfs_statfs() outside q->limits_locks instead,
because looks like no reason to hold q->limits_locks while getting
discord configs.

Chain exists of:
  &sbi->fat_lock --> &q->q_usage_counter(io)#17 --> &q->limits_lock

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&q->limits_lock);
                               lock(&q->q_usage_counter(io)#17);
                               lock(&q->limits_lock);
  lock(&sbi->fat_lock);

 *** DEADLOCK ***

Reported-by: syzbot+a5d8c609c02f508672cc@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=a5d8c609c02f508672cc
Reviewed-by: Ming Lei 
Signed-off-by: OGAWA Hirofumi 
Signed-off-by: Jens Axboe 
Stable-dep-of: f5c84eff634b ("loop: Add sanity check for read/write_iter")
Signed-off-by: Sasha Levin

loop: Simplify discard granularity calc

2025-05-18T06:24:56+00:00

[ Upstream commit d47de6ac8842327ae1c782670283450159c55d5b ]

A bdev discard granularity is always at least SECTOR_SIZE, so don't check
for a zero value.

Suggested-by: Christoph Hellwig 
Signed-off-by: John Garry 
Link: https://lore.kernel.org/r/20241101092215.422428-1-john.g.garry@oracle.com
Signed-off-by: Jens Axboe 
Stable-dep-of: f5c84eff634b ("loop: Add sanity check for read/write_iter")
Signed-off-by: Sasha Levin

loop: Use bdev limit helpers for configuring discard

2025-05-18T06:24:56+00:00

[ Upstream commit 8d3fd059dd289e6c322e5741ad56794bcce699a2 ]

Instead of directly looking at the request_queue limits, use the bdev
limits helpers, which is preferable.

Signed-off-by: John Garry 
Link: https://lore.kernel.org/r/20241030111900.3981223-1-john.g.garry@oracle.com
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

2025-04-25T08:47:52+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