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 <evgreen@chromium.org>
Reviewed-by: Gwendal Grignou <gwendal@chromium.org>
Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
[used updated version of Evan's comment in loop_config_discard()]
[moved backingq to local scope, removed redundant braces]
Signed-off-by: Andrzej Pietrasiewicz <andrzej.p@collabora.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Properly plumb out EOPNOTSUPP from loop driver operations, which may
get returned when for instance a discard operation is attempted but not
supported by the underlying block device. Before this change, everything
was reported in the log as an I/O error, which is scary and not
helpful in debugging.
Signed-off-by: Evan Green <evgreen@chromium.org>
Reviewed-by: Gwendal Grignou <gwendal@chromium.org>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Andrzej Pietrasiewicz <andrzej.p@collabora.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
__loop_update_dio() can be called as a part of loop_set_fd(), when the
block queue is not yet up and running; avoid freezing the block queue in
that case, since that is an expensive operation.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Signed-off-by: Martijn Coenen <maco@android.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Return early in loop_set_block_size() if the requested block size is
identical to the one we already have; this avoids expensive calls to
freeze the block queue.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Martijn Coenen <maco@android.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
In general drivers should never mess with partition tables directly.
Unfortunately s390 and loop do for somewhat historic reasons, but they
can use bdev_disk_changed directly instead when we export it as they
satisfy the sanity checks we have in __blkdev_reread_part.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Stefan Haberland <sth@linux.ibm.com> [dasd]
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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: 19372e2769 ("loop: implement REQ_OP_WRITE_ZEROES")
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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 <hch@lst.de>
Signed-off-by: Martijn Coenen <maco@android.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Merge tag 'for-5.4/block-2019-09-16' of git://git.kernel.dk/linux-block
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
...
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 <axboe@kernel.dk>
Signed-off-by: Alessio Balsini <balsini@android.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
A deadlock with this stacktrace was observed.
The loop thread does a GFP_KERNEL allocation, it calls into dm-bufio
shrinker and the shrinker depends on I/O completion in the dm-bufio
subsystem.
In order to fix the deadlock (and other similar ones), we set the flag
PF_MEMALLOC_NOIO at loop thread entry.
PID: 474 TASK: ffff8813e11f4600 CPU: 10 COMMAND: "kswapd0"
#0 [ffff8813dedfb938] __schedule at ffffffff8173f405
#1 [ffff8813dedfb990] schedule at ffffffff8173fa27
#2 [ffff8813dedfb9b0] schedule_timeout at ffffffff81742fec
#3 [ffff8813dedfba60] io_schedule_timeout at ffffffff8173f186
#4 [ffff8813dedfbaa0] bit_wait_io at ffffffff8174034f
#5 [ffff8813dedfbac0] __wait_on_bit at ffffffff8173fec8
#6 [ffff8813dedfbb10] out_of_line_wait_on_bit at ffffffff8173ff81
#7 [ffff8813dedfbb90] __make_buffer_clean at ffffffffa038736f [dm_bufio]
#8 [ffff8813dedfbbb0] __try_evict_buffer at ffffffffa0387bb8 [dm_bufio]
#9 [ffff8813dedfbbd0] dm_bufio_shrink_scan at ffffffffa0387cc3 [dm_bufio]
#10 [ffff8813dedfbc40] shrink_slab at ffffffff811a87ce
#11 [ffff8813dedfbd30] shrink_zone at ffffffff811ad778
#12 [ffff8813dedfbdc0] kswapd at ffffffff811ae92f
#13 [ffff8813dedfbec0] kthread at ffffffff810a8428
#14 [ffff8813dedfbf50] ret_from_fork at ffffffff81745242
PID: 14127 TASK: ffff881455749c00 CPU: 11 COMMAND: "loop1"
#0 [ffff88272f5af228] __schedule at ffffffff8173f405
#1 [ffff88272f5af280] schedule at ffffffff8173fa27
#2 [ffff88272f5af2a0] schedule_preempt_disabled at ffffffff8173fd5e
#3 [ffff88272f5af2b0] __mutex_lock_slowpath at ffffffff81741fb5
#4 [ffff88272f5af330] mutex_lock at ffffffff81742133
#5 [ffff88272f5af350] dm_bufio_shrink_count at ffffffffa03865f9 [dm_bufio]
#6 [ffff88272f5af380] shrink_slab at ffffffff811a86bd
#7 [ffff88272f5af470] shrink_zone at ffffffff811ad778
#8 [ffff88272f5af500] do_try_to_free_pages at ffffffff811adb34
#9 [ffff88272f5af590] try_to_free_pages at ffffffff811adef8
#10 [ffff88272f5af610] __alloc_pages_nodemask at ffffffff811a09c3
#11 [ffff88272f5af710] alloc_pages_current at ffffffff811e8b71
#12 [ffff88272f5af760] new_slab at ffffffff811f4523
#13 [ffff88272f5af7b0] __slab_alloc at ffffffff8173a1b5
#14 [ffff88272f5af880] kmem_cache_alloc at ffffffff811f484b
#15 [ffff88272f5af8d0] do_blockdev_direct_IO at ffffffff812535b3
#16 [ffff88272f5afb00] __blockdev_direct_IO at ffffffff81255dc3
#17 [ffff88272f5afb30] xfs_vm_direct_IO at ffffffffa01fe3fc [xfs]
#18 [ffff88272f5afb90] generic_file_read_iter at ffffffff81198994
#19 [ffff88272f5afc50] __dta_xfs_file_read_iter_2398 at ffffffffa020c970 [xfs]
#20 [ffff88272f5afcc0] lo_rw_aio at ffffffffa0377042 [loop]
#21 [ffff88272f5afd70] loop_queue_work at ffffffffa0377c3b [loop]
#22 [ffff88272f5afe60] kthread_worker_fn at ffffffff810a8a0c
#23 [ffff88272f5afec0] kthread at ffffffff810a8428
#24 [ffff88272f5aff50] ret_from_fork at ffffffff81745242
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Commit 33ec3e53e7 ("loop: Don't change loop device under exclusive
opener") made LOOP_SET_FD ioctl acquire exclusive block device reference
while it updates loop device binding. However this can make perfectly
valid mount(2) fail with EBUSY due to racing LOOP_SET_FD holding
temporarily the exclusive bdev reference in cases like this:
for i in {a..z}{a..z}; do
dd if=/dev/zero of=$i.image bs=1k count=0 seek=1024
mkfs.ext2 $i.image
mkdir mnt$i
done
echo "Run"
for i in {a..z}{a..z}; do
mount -o loop -t ext2 $i.image mnt$i &
done
Fix the problem by not getting full exclusive bdev reference in
LOOP_SET_FD but instead just mark the bdev as being claimed while we
update the binding information. This just blocks new exclusive openers
instead of failing them with EBUSY thus fixing the problem.
Fixes: 33ec3e53e7 ("loop: Don't change loop device under exclusive opener")
Cc: stable@vger.kernel.org
Tested-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
If we pass pages through an iov_iter we always already have a reference
in the caller. Thus remove the ITER_BVEC_FLAG_NO_REF and don't take
reference to pages by default for bvec backed iov_iters.
Reviewed-by: Minwoo Im <minwoo.im.dev@gmail.com>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Loop module allows calling LOOP_SET_FD while there are other openers of
the loop device. Even exclusive ones. This can lead to weird
consequences such as kernel deadlocks like:
mount_bdev() lo_ioctl()
udf_fill_super()
udf_load_vrs()
sb_set_blocksize() - sets desired block size B
udf_tread()
sb_bread()
__bread_gfp(bdev, block, B)
loop_set_fd()
set_blocksize()
- now __getblk_slow() indefinitely loops because B != bdev
block size
Fix the problem by disallowing LOOP_SET_FD ioctl when there are
exclusive openers of a loop device.
[Deliberately chosen not to CC stable as a user with priviledges to
trigger this race has other means of taking the system down and this
has a potential of breaking some weird userspace setup]
Reported-and-tested-by: syzbot+10007d66ca02b08f0e60@syzkaller.appspotmail.com
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
loop is one block device, for any bio submitted to this device,
the upper layer does guarantee that pages added to loop's bio won't
go away when the bio is in-flight.
So mark loop's bvec as ITER_BVEC_FLAG_NO_REF then get_page/put_page
can be saved for serving loop's IO.
Cc: linux-fsdevel@vger.kernel.org
Cc: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
The loop driver always declares the rotational flag of its device as
rotational, even when the device of the mapped file is nonrotational,
as is the case with SSDs or on tmpfs. This can confuse filesystem tools
which are SSD-aware; in my case I frequently forget to tell mkfs.btrfs
that my loop device on tmpfs is nonrotational, and that I really don't
need any automatic metadata redundancy.
The attached patch fixes this by introspecting the rotational flag of the
mapped file's underlying block device, if it exists. If the mapped file's
filesystem has no associated block device - as is the case on e.g. tmpfs -
we assume nonrotational storage. If there is a better way to identify such
non-devices I'd love to hear them.
Cc: Jens Axboe <axboe@kernel.dk>
Cc: linux-block@vger.kernel.org
Cc: holger@applied-asynchrony.com
Signed-off-by: Holger Hoffstätte <holger.hoffstaette@googlemail.com>
Signed-off-by: Gwendal Grignou <gwendal@chromium.org>
Signed-off-by: Benjamin Gordon <bmgordon@chromium.org>
Reviewed-by: Guenter Roeck <groeck@chromium.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Commit 758a58d0bc ("loop: set GENHD_FL_NO_PART_SCAN after
blkdev_reread_part()") separates "lo->lo_backing_file = NULL" and
"lo->lo_state = Lo_unbound" into different critical regions protected by
loop_ctl_mutex.
However, there is below race that the NULL lo->lo_backing_file would be
accessed when the backend of a loop is another loop device, e.g., loop0's
backend is a file, while loop1's backend is loop0.
loop0's backend is file loop1's backend is loop0
__loop_clr_fd()
mutex_lock(&loop_ctl_mutex);
lo->lo_backing_file = NULL; --> set to NULL
mutex_unlock(&loop_ctl_mutex);
loop_set_fd()
mutex_lock_killable(&loop_ctl_mutex);
loop_validate_file()
f = l->lo_backing_file; --> NULL
access if loop0 is not Lo_unbound
mutex_lock(&loop_ctl_mutex);
lo->lo_state = Lo_unbound;
mutex_unlock(&loop_ctl_mutex);
lo->lo_backing_file should be accessed only when the loop device is
Lo_bound.
In fact, the problem has been introduced already in commit 7ccd0791d9
("loop: Push loop_ctl_mutex down into loop_clr_fd()") after which
loop_validate_file() could see devices in Lo_rundown state with which it
did not count. It was harmless at that point but still.
Fixes: 7ccd0791d9 ("loop: Push loop_ctl_mutex down into loop_clr_fd()")
Reported-by: syzbot+9bdc1adc1c55e7fe765b@syzkaller.appspotmail.com
Signed-off-by: Dongli Zhang <dongli.zhang@oracle.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Commit 0da03cab87
("loop: Fix deadlock when calling blkdev_reread_part()") moves
blkdev_reread_part() out of the loop_ctl_mutex. However,
GENHD_FL_NO_PART_SCAN is set before __blkdev_reread_part(). As a result,
__blkdev_reread_part() will fail the check of GENHD_FL_NO_PART_SCAN and
will not rescan the loop device to delete all partitions.
Below are steps to reproduce the issue:
step1 # dd if=/dev/zero of=tmp.raw bs=1M count=100
step2 # losetup -P /dev/loop0 tmp.raw
step3 # parted /dev/loop0 mklabel gpt
step4 # parted -a none -s /dev/loop0 mkpart primary 64s 1
step5 # losetup -d /dev/loop0
Step5 will not be able to delete /dev/loop0p1 (introduced by step4) and
there is below kernel warning message:
[ 464.414043] __loop_clr_fd: partition scan of loop0 failed (rc=-22)
This patch sets GENHD_FL_NO_PART_SCAN after blkdev_reread_part().
Fixes: 0da03cab87 ("loop: Fix deadlock when calling blkdev_reread_part()")
Signed-off-by: Dongli Zhang <dongli.zhang@oracle.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Do not print warn message when the partition scan returns 0.
Fixes: d57f3374ba ("loop: Move special partition reread handling in loop_clr_fd()")
Signed-off-by: Dongli Zhang <dongli.zhang@oracle.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
QUEUE_FLAG_NO_SG_MERGE has been killed, so kill BLK_MQ_F_SG_MERGE too.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
iov_iter is implemented on bvec itererator helpers, so it is safe to pass
multi-page bvec to it, and this way is much more efficient than passing one
page in each bvec.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
If we don't drop caches used in old offset or block_size, we can get old data
from new offset/block_size, which gives unexpected data to user.
For example, Martijn found a loopback bug in the below scenario.
1) LOOP_SET_FD loads first two pages on loop file
2) LOOP_SET_STATUS64 changes the offset on the loop file
3) mount is failed due to the cached pages having wrong superblock
Cc: Jens Axboe <axboe@kernel.dk>
Cc: linux-block@vger.kernel.org
Reported-by: Martijn Coenen <maco@google.com>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
blk_mq_init_queue() will not return NULL pointer to its caller,
so it's better to replace IS_ERR_OR_NULL using IS_ERR in loop_add().
If in the future things change to check NULL pointer inside loop_add(),
we should return -ENOMEM as return code instead of PTR_ERR(NULL).
Signed-off-by: Chengguang Xu <cgxu519@gmx.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Prior patches ensured that any bio that interacts with a request_queue
is properly associated with a blkg. This makes bio->bi_css unnecessary
as blkg maintains a reference to blkcg already.
This removes the bio field bi_css and transfers corresponding uses to
access via bi_blkg.
Signed-off-by: Dennis Zhou <dennis@kernel.org>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Commit 0a42e99b58 ("loop: Get rid of loop_index_mutex") forgot to
remove mutex_unlock(&loop_ctl_mutex) from loop_control_ioctl() when
replacing loop_index_mutex with loop_ctl_mutex.
Fixes: 0a42e99b58 ("loop: Get rid of loop_index_mutex")
Reported-by: syzbot <syzbot+c0138741c2290fc5e63f@syzkaller.appspotmail.com>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
The nested acquisition of loop_ctl_mutex (->lo_ctl_mutex back then) has
been introduced by commit f028f3b2f9 "loop: fix circular locking in
loop_clr_fd()" to fix lockdep complains about bd_mutex being acquired
after lo_ctl_mutex during partition rereading. Now that these are
properly fixed, let's stop fooling lockdep.
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Code in loop_change_fd() drops reference to the old file (and also the
new file in a failure case) under loop_ctl_mutex. Similarly to a
situation in loop_set_fd() this can create a circular locking dependency
if this was the last reference holding the file open. Delay dropping of
the file reference until we have released loop_ctl_mutex.
Reported-by: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Calling blkdev_reread_part() under loop_ctl_mutex causes lockdep to
complain about circular lock dependency between bdev->bd_mutex and
lo->lo_ctl_mutex. The problem is that on loop device open or close
lo_open() and lo_release() get called with bdev->bd_mutex held and they
need to acquire loop_ctl_mutex. OTOH when loop_reread_partitions() is
called with loop_ctl_mutex held, it will call blkdev_reread_part() which
acquires bdev->bd_mutex. See syzbot report for details [1].
Move call to blkdev_reread_part() in __loop_clr_fd() from under
loop_ctl_mutex to finish fixing of the lockdep warning and the possible
deadlock.
[1] https://syzkaller.appspot.com/bug?id=bf154052f0eea4bc7712499e4569505907d1588
Reported-by: syzbot <syzbot+4684a000d5abdade83fac55b1e7d1f935ef1936e@syzkaller.appspotmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Calling loop_reread_partitions() under loop_ctl_mutex causes lockdep to
complain about circular lock dependency between bdev->bd_mutex and
lo->lo_ctl_mutex. The problem is that on loop device open or close
lo_open() and lo_release() get called with bdev->bd_mutex held and they
need to acquire loop_ctl_mutex. OTOH when loop_reread_partitions() is
called with loop_ctl_mutex held, it will call blkdev_reread_part() which
acquires bdev->bd_mutex. See syzbot report for details [1].
Move all calls of loop_rescan_partitions() out of loop_ctl_mutex to
avoid lockdep warning and fix deadlock possibility.
[1] https://syzkaller.appspot.com/bug?id=bf154052f0eea4bc7712499e4569505907d1588
Reported-by: syzbot <syzbot+4684a000d5abdade83fac55b1e7d1f935ef1936e@syzkaller.appspotmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
The call of __blkdev_reread_part() from loop_reread_partition() happens
only when we need to invalidate partitions from loop_release(). Thus
move a detection for this into loop_clr_fd() and simplify
loop_reread_partition().
This makes loop_reread_partition() safe to use without loop_ctl_mutex
because we use only lo->lo_number and lo->lo_file_name in case of error
for reporting purposes (thus possibly reporting outdate information is
not a big deal) and we are safe from 'lo' going away under us by
elevated lo->lo_refcnt.
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Push loop_ctl_mutex down to loop_change_fd(). We will need this to be
able to call loop_reread_partitions() without loop_ctl_mutex.
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Push lo_ctl_mutex down to loop_set_fd(). We will need this to be able to
call loop_reread_partitions() without lo_ctl_mutex.
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Push loop_ctl_mutex down to loop_set_status(). We will need this to be
able to call loop_reread_partitions() without loop_ctl_mutex.
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Push loop_ctl_mutex down to loop_get_status() to avoid the unusual
convention that the function gets called with loop_ctl_mutex held and
releases it.
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
loop_clr_fd() has a weird locking convention that is expects
loop_ctl_mutex held, releases it on success and keeps it on failure.
Untangle the mess by moving locking of loop_ctl_mutex into
loop_clr_fd().
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Move setting of lo_state to Lo_rundown out into the callers. That will
allow us to unlock loop_ctl_mutex while the loop device is protected
from other changes by its special state.
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Push acquisition of lo_ctl_mutex down into individual ioctl handling
branches. This is a preparatory step for pushing the lock down into
individual ioctl handling functions so that they can release the lock as
they need it. We also factor out some simple ioctl handlers that will
not need any special handling to reduce unnecessary code duplication.
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Now that loop_ctl_mutex is global, just get rid of loop_index_mutex as
there is no good reason to keep these two separate and it just
complicates the locking.
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
__loop_release() has a single call site. Fold it there. This is
currently not a huge win but it will make following replacement of
loop_index_mutex more obvious.
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
syzbot is reporting NULL pointer dereference [1] which is caused by
race condition between ioctl(loop_fd, LOOP_CLR_FD, 0) versus
ioctl(other_loop_fd, LOOP_SET_FD, loop_fd) due to traversing other
loop devices at loop_validate_file() without holding corresponding
lo->lo_ctl_mutex locks.
Since ioctl() request on loop devices is not frequent operation, we don't
need fine grained locking. Let's use global lock in order to allow safe
traversal at loop_validate_file().
Note that syzbot is also reporting circular locking dependency between
bdev->bd_mutex and lo->lo_ctl_mutex [2] which is caused by calling
blkdev_reread_part() with lock held. This patch does not address it.
[1] https://syzkaller.appspot.com/bug?id=f3cfe26e785d85f9ee259f385515291d21bd80a3
[2] https://syzkaller.appspot.com/bug?id=bf154052f0eea4bc7712499e4569505907d15889
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Reported-by: syzbot <syzbot+bf89c128e05dd6c62523@syzkaller.appspotmail.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
vfs_getattr() needs "struct path" rather than "struct file".
Let's use path_get()/path_put() rather than get_file()/fput().
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Merge tag 'for-linus-20181102' of git://git.kernel.dk/linux-block
Pull block layer fixes from Jens Axboe:
"The biggest part of this pull request is the revert of the blkcg
cleanup series. It had one fix earlier for a stacked device issue, but
another one was reported. Rather than play whack-a-mole with this,
revert the entire series and try again for the next kernel release.
Apart from that, only small fixes/changes.
Summary:
- Indentation fixup for mtip32xx (Colin Ian King)
- The blkcg cleanup series revert (Dennis Zhou)
- Two NVMe fixes. One fixing a regression in the nvme request
initialization in this merge window, causing nvme-fc to not work.
The other is a suspend/resume p2p resource issue (James, Keith)
- Fix sg discard merge, allowing us to merge in cases where we didn't
before (Jianchao Wang)
- Call rq_qos_exit() after the queue is frozen, preventing a hang
(Ming)
- Fix brd queue setup, fixing an oops if we fail setting up all
devices (Ming)"
* tag 'for-linus-20181102' of git://git.kernel.dk/linux-block:
nvme-pci: fix conflicting p2p resource adds
nvme-fc: fix request private initialization
blkcg: revert blkcg cleanups series
block: brd: associate with queue until adding disk
block: call rq_qos_exit() after queue is frozen
mtip32xx: clean an indentation issue, remove extraneous tabs
block: fix the DISCARD request merge
Pull AFS updates from Al Viro:
"AFS series, with some iov_iter bits included"
* 'work.afs' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (26 commits)
missing bits of "iov_iter: Separate type from direction and use accessor functions"
afs: Probe multiple fileservers simultaneously
afs: Fix callback handling
afs: Eliminate the address pointer from the address list cursor
afs: Allow dumping of server cursor on operation failure
afs: Implement YFS support in the fs client
afs: Expand data structure fields to support YFS
afs: Get the target vnode in afs_rmdir() and get a callback on it
afs: Calc callback expiry in op reply delivery
afs: Fix FS.FetchStatus delivery from updating wrong vnode
afs: Implement the YFS cache manager service
afs: Remove callback details from afs_callback_break struct
afs: Commit the status on a new file/dir/symlink
afs: Increase to 64-bit volume ID and 96-bit vnode ID for YFS
afs: Don't invoke the server to read data beyond EOF
afs: Add a couple of tracepoints to log I/O errors
afs: Handle EIO from delivery function
afs: Fix TTL on VL server and address lists
afs: Implement VL server rotation
afs: Improve FS server rotation error handling
...
In the iov_iter struct, separate the iterator type from the iterator
direction and use accessor functions to access them in most places.
Convert a bunch of places to use switch-statements to access them rather
then chains of bitwise-AND statements. This makes it easier to add further
iterator types. Also, this can be more efficient as to implement a switch
of small contiguous integers, the compiler can use ~50% fewer compare
instructions than it has to use bitwise-and instructions.
Further, cease passing the iterator type into the iterator setup function.
The iterator function can set that itself. Only the direction is required.
Signed-off-by: David Howells <dhowells@redhat.com>
Prior patches ensured that all bios are now associated with some blkg.
This now makes bio->bi_css unnecessary as blkg maintains a reference to
the blkcg already.
This patch removes the field bi_css and transfers corresponding uses to
access via bi_blkg.
Signed-off-by: Dennis Zhou <dennisszhou@gmail.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
In preparation to enabling -Wimplicit-fallthrough, mark switch cases
where we are expecting to fall through.
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Pointer inode is being assigned but is never used hence it is redundant
and can be removed.
Cleans up clang warning:
warning: variable 'inode' set but not used [-Wunused-but-set-variable]
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This change adds LOOP_SET_BLOCK_SIZE as one of the supported ioctls
in lo_compat_ioctl. It only takes an unsigned long argument, and
in practice a 32-bit value works fine.
Reviewed-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: Evan Green <evgreen@chromium.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Evan Green
Martijn Coenen
Christoph Hellwig
Darrick J. Wong
Linus Torvalds
Alessio Balsini
Mikulas Patocka
Jan Kara
Ming Lei
Holger Hoffstätte
Dongli Zhang
Jaegeuk Kim
Chengguang Xu
Dennis Zhou
Tetsuo Handa
David Howells
Dennis Zhou (Facebook)
Gustavo A. R. Silva
Colin Ian King