linux-stable.git/drivers/block/loop.c, branch v5.4.232

loop: Check for overflow while configuring loop

2022-09-05T08:27:43+00:00

commit c490a0b5a4f36da3918181a8acdc6991d967c5f3 upstream.

The userspace can configure a loop using an ioctl call, wherein
a configuration of type loop_config is passed (see lo_ioctl()'s
case on line 1550 of drivers/block/loop.c). This proceeds to call
loop_configure() which in turn calls loop_set_status_from_info()
(see line 1050 of loop.c), passing &config->info which is of type
loop_info64*. This function then sets the appropriate values, like
the offset.

loop_device has lo_offset of type loff_t (see line 52 of loop.c),
which is typdef-chained to long long, whereas loop_info64 has
lo_offset of type __u64 (see line 56 of include/uapi/linux/loop.h).

The function directly copies offset from info to the device as
follows (See line 980 of loop.c):
	lo->lo_offset = info->lo_offset;

This results in an overflow, which triggers a warning in iomap_iter()
due to a call to iomap_iter_done() which has:
	WARN_ON_ONCE(iter->iomap.offset > iter->pos);

Thus, check for negative value during loop_set_status_from_info().

Bug report: https://syzkaller.appspot.com/bug?id=c620fe14aac810396d3c3edc9ad73848bf69a29e

Reported-and-tested-by: syzbot+a8e049cd3abd342936b6@syzkaller.appspotmail.com
Cc: stable@vger.kernel.org
Reviewed-by: Matthew Wilcox (Oracle) 
Signed-off-by: Siddh Raman Pant 
Reviewed-by: Christoph Hellwig 
Link: https://lore.kernel.org/r/20220823160810.181275-1-code@siddh.me
Signed-off-by: Jens Axboe 
Signed-off-by: Greg Kroah-Hartman

loop: use sysfs_emit() in the sysfs xxx show()

2022-04-15T12:18:22+00:00

[ Upstream commit b27824d31f09ea7b4a6ba2c1b18bd328df3e8bed ]

sprintf does not know the PAGE_SIZE maximum of the temporary buffer
used for outputting sysfs content and it's possible to overrun the
PAGE_SIZE buffer length.

Use a generic sysfs_emit function that knows the size of the
temporary buffer and ensures that no overrun is done for offset
attribute in
loop_attr_[offset|sizelimit|autoclear|partscan|dio]_show() callbacks.

Signed-off-by: Chaitanya Kulkarni 
Reviewed-by: Himanshu Madhani 
Link: https://lore.kernel.org/r/20220215213310.7264-2-kch@nvidia.com
Signed-off-by: Jens Axboe 
Signed-off-by: Sasha Levin

block: loop: set discard granularity and alignment for block device backed loop

2020-09-03T09:27:01+00:00

commit bcb21c8cc9947286211327d663ace69f07d37a76 upstream.

In case of block device backend, if the backend supports write zeros, the
loop device will set queue flag of QUEUE_FLAG_DISCARD. However,
limits.discard_granularity isn't setup, and this way is wrong,
see the following description in Documentation/ABI/testing/sysfs-block:

	A discard_granularity of 0 means that the device does not support
	discard functionality.

Especially 9b15d109a6b2 ("block: improve discard bio alignment in
__blkdev_issue_discard()") starts to take q->limits.discard_granularity
for computing max discard sectors. And zero discard granularity may cause
kernel oops, or fail discard request even though the loop queue claims
discard support via QUEUE_FLAG_DISCARD.

Fix the issue by setup discard granularity and alignment.

Fixes: c52abf563049 ("loop: Better discard support for block devices")
Signed-off-by: Ming Lei 
Reviewed-by: Christoph Hellwig 
Acked-by: Coly Li 
Cc: Hannes Reinecke 
Cc: Xiao Ni 
Cc: Martin K. Petersen 
Cc: Evan Green 
Cc: Gwendal Grignou 
Cc: Chaitanya Kulkarni 
Cc: Andrzej Pietrasiewicz 
Cc: Christoph Hellwig 
Cc: 
Signed-off-by: Jens Axboe 
Signed-off-by: Greg Kroah-Hartman

loop: be paranoid on exit and prevent new additions / removals

2020-08-19T06:15:59+00:00

[ Upstream commit 200f93377220504c5e56754823e7adfea6037f1a ]

Be pedantic on removal as well and hold the mutex.
This should prevent uses of addition while we exit.

Signed-off-by: Luis Chamberlain 
Reviewed-by: Ming Lei 
Reviewed-by: Christoph Hellwig 
Signed-off-by: Jens Axboe 
Signed-off-by: Sasha Levin

loop: replace kill_bdev with invalidate_bdev

2020-06-30T19:36:52+00:00

commit f4bd34b139a3fa2808c4205f12714c65e1548c6c upstream.

When a filesystem is mounted on a loop device and on a loop ioctl
LOOP_SET_STATUS64, because of kill_bdev, buffer_head mappings are getting
destroyed.
kill_bdev
  truncate_inode_pages
    truncate_inode_pages_range
      do_invalidatepage
        block_invalidatepage
          discard_buffer  -->clear BH_Mapped flag

sb_bread
  __bread_gfp
  bh = __getblk_gfp
  -->discard_buffer clear BH_Mapped flag
  __bread_slow
    submit_bh
      submit_bh_wbc
        BUG_ON(!buffer_mapped(bh))  --> hit this BUG_ON

Fixes: 5db470e229e2 ("loop: drop caches if offset or block_size are changed")
Signed-off-by: Zheng Bin 
Reviewed-by: Christoph Hellwig 
Reviewed-by: Bart Van Assche 
Signed-off-by: Jens Axboe 
Signed-off-by: Greg Kroah-Hartman

loop: Better discard support for block devices

2020-04-29T14:33:01+00:00

[ Upstream commit c52abf563049e787c1341cdf15c7dbe1bfbc951b ]

If the backing device for a loop device is itself a block device,
then mirror the "write zeroes" capabilities of the underlying
block device into the loop device. Copy this capability into both
max_write_zeroes_sectors and max_discard_sectors of the loop device.

The reason for this is that REQ_OP_DISCARD on a loop device translates
into blkdev_issue_zeroout(), rather than blkdev_issue_discard(). This
presents a consistent interface for loop devices (that discarded data
is zeroed), regardless of the backing device type of the loop device.
There should be no behavior change for loop devices backed by regular
files.

This change fixes blktest block/003, and removes an extraneous
error print in block/013 when testing on a loop device backed
by a block device that does not support discard.

Signed-off-by: Evan Green 
Reviewed-by: Gwendal Grignou 
Reviewed-by: Chaitanya Kulkarni 
[used updated version of Evan's comment in loop_config_discard()]
[moved backingq to local scope, removed redundant braces]
Signed-off-by: Andrzej Pietrasiewicz 
Reviewed-by: Christoph Hellwig 
Signed-off-by: Jens Axboe 
Signed-off-by: Sasha Levin

loop: fix no-unmap write-zeroes request behavior

2019-12-31T15:44:31+00:00

[ Upstream commit efcfec579f6139528c9e6925eca2bc4a36da65c6 ]

Currently, if the loop device receives a WRITE_ZEROES request, it asks
the underlying filesystem to punch out the range.  This behavior is
correct if unmapping is allowed.  However, a NOUNMAP request means that
the caller doesn't want us to free the storage backing the range, so
punching out the range is incorrect behavior.

To satisfy a NOUNMAP | WRITE_ZEROES request, loop should ask the
underlying filesystem to FALLOC_FL_ZERO_RANGE, which is (according to
the fallocate documentation) required to ensure that the entire range is
backed by real storage, which suffices for our purposes.

Fixes: 19372e2769179dd ("loop: implement REQ_OP_WRITE_ZEROES")
Signed-off-by: Darrick J. Wong 
Reviewed-by: Christoph Hellwig 
Signed-off-by: Jens Axboe 
Signed-off-by: Sasha Levin

loop: change queue block size to match when using DIO

2019-10-01T15:36:01+00:00

The loop driver assumes that if the passed in fd is opened with
O_DIRECT, the caller wants to use direct I/O on the loop device.
However, if the underlying block device has a different block size than
the loop block queue, direct I/O can't be enabled. Instead of requiring
userspace to manually change the blocksize and re-enable direct I/O,
just change the queue block sizes to match, as well as the io_min size.

Reviewed-by: Christoph Hellwig 
Signed-off-by: Martijn Coenen 
Signed-off-by: Jens Axboe

Merge tag 'for-5.4/block-2019-09-16' of git://git.kernel.dk/linux-block

2019-09-17T23:57:47+00:00

Pull block updates from Jens Axboe:

 - Two NVMe pull requests:
     - ana log parse fix from Anton
     - nvme quirks support for Apple devices from Ben
     - fix missing bio completion tracing for multipath stack devices
       from Hannes and Mikhail
     - IP TOS settings for nvme rdma and tcp transports from Israel
     - rq_dma_dir cleanups from Israel
     - tracing for Get LBA Status command from Minwoo
     - Some nvme-tcp cleanups from Minwoo, Potnuri and Myself
     - Some consolidation between the fabrics transports for handling
       the CAP register
     - reset race with ns scanning fix for fabrics (move fabrics
       commands to a dedicated request queue with a different lifetime
       from the admin request queue)."
     - controller reset and namespace scan races fixes
     - nvme discovery log change uevent support
     - naming improvements from Keith
     - multiple discovery controllers reject fix from James
     - some regular cleanups from various people

 - Series fixing (and re-fixing) null_blk debug printing and nr_devices
   checks (André)

 - A few pull requests from Song, with fixes from Andy, Guoqing,
   Guilherme, Neil, Nigel, and Yufen.

 - REQ_OP_ZONE_RESET_ALL support (Chaitanya)

 - Bio merge handling unification (Christoph)

 - Pick default elevator correctly for devices with special needs
   (Damien)

 - Block stats fixes (Hou)

 - Timeout and support devices nbd fixes (Mike)

 - Series fixing races around elevator switching and device add/remove
   (Ming)

 - sed-opal cleanups (Revanth)

 - Per device weight support for BFQ (Fam)

 - Support for blk-iocost, a new model that can properly account cost of
   IO workloads. (Tejun)

 - blk-cgroup writeback fixes (Tejun)

 - paride queue init fixes (zhengbin)

 - blk_set_runtime_active() cleanup (Stanley)

 - Block segment mapping optimizations (Bart)

 - lightnvm fixes (Hans/Minwoo/YueHaibing)

 - Various little fixes and cleanups

* tag 'for-5.4/block-2019-09-16' of git://git.kernel.dk/linux-block: (186 commits)
  null_blk: format pr_* logs with pr_fmt
  null_blk: match the type of parameter nr_devices
  null_blk: do not fail the module load with zero devices
  block: also check RQF_STATS in blk_mq_need_time_stamp()
  block: make rq sector size accessible for block stats
  bfq: Fix bfq linkage error
  raid5: use bio_end_sector in r5_next_bio
  raid5: remove STRIPE_OPS_REQ_PENDING
  md: add feature flag MD_FEATURE_RAID0_LAYOUT
  md/raid0: avoid RAID0 data corruption due to layout confusion.
  raid5: don't set STRIPE_HANDLE to stripe which is in batch list
  raid5: don't increment read_errors on EILSEQ return
  nvmet: fix a wrong error status returned in error log page
  nvme: send discovery log page change events to userspace
  nvme: add uevent variables for controller devices
  nvme: enable aen regardless of the presence of I/O queues
  nvme-fabrics: allow discovery subsystems accept a kato
  nvmet: Use PTR_ERR_OR_ZERO() in nvmet_init_discovery()
  nvme: Remove redundant assignment of cq vector
  nvme: Assign subsys instance from first ctrl
  ...

loop: Add LOOP_SET_DIRECT_IO to compat ioctl

2019-08-09T03:39:02+00:00

Enabling Direct I/O with loop devices helps reducing memory usage by
avoiding double caching.  32 bit applications running on 64 bits systems
are currently not able to request direct I/O because is missing from the
lo_compat_ioctl.

This patch fixes the compatibility issue mentioned above by exporting
LOOP_SET_DIRECT_IO as additional lo_compat_ioctl() entry.
The input argument for this ioctl is a single long converted to a 1-bit
boolean, so compatibility is preserved.

Cc: Jens Axboe 
Signed-off-by: Alessio Balsini 
Signed-off-by: Jens Axboe