Commit Graph

170 Commits

Author SHA1 Message Date
Ming-Hung Tsai
00586b78ee dm cache: prevent BUG_ON by blocking retries on failed device resumes
[ Upstream commit 5da692e226 ]

A cache device failing to resume due to mapping errors should not be
retried, as the failure leaves a partially initialized policy object.
Repeating the resume operation risks triggering BUG_ON when reloading
cache mappings into the incomplete policy object.

Reproduce steps:

1. create a cache metadata consisting of 512 or more cache blocks,
   with some mappings stored in the first array block of the mapping
   array. Here we use cache_restore v1.0 to build the metadata.

cat <<EOF >> cmeta.xml
<superblock uuid="" block_size="128" nr_cache_blocks="512" \
policy="smq" hint_width="4">
  <mappings>
    <mapping cache_block="0" origin_block="0" dirty="false"/>
  </mappings>
</superblock>
EOF
dmsetup create cmeta --table "0 8192 linear /dev/sdc 0"
cache_restore -i cmeta.xml -o /dev/mapper/cmeta --metadata-version=2
dmsetup remove cmeta

2. wipe the second array block of the mapping array to simulate
   data degradations.

mapping_root=$(dd if=/dev/sdc bs=1c count=8 skip=192 \
2>/dev/null | hexdump -e '1/8 "%u\n"')
ablock=$(dd if=/dev/sdc bs=1c count=8 skip=$((4096*mapping_root+2056)) \
2>/dev/null | hexdump -e '1/8 "%u\n"')
dd if=/dev/zero of=/dev/sdc bs=4k count=1 seek=$ablock

3. try bringing up the cache device. The resume is expected to fail
   due to the broken array block.

dmsetup create cmeta --table "0 8192 linear /dev/sdc 0"
dmsetup create cdata --table "0 65536 linear /dev/sdc 8192"
dmsetup create corig --table "0 524288 linear /dev/sdc 262144"
dmsetup create cache --notable
dmsetup load cache --table "0 524288 cache /dev/mapper/cmeta \
/dev/mapper/cdata /dev/mapper/corig 128 2 metadata2 writethrough smq 0"
dmsetup resume cache

4. try resuming the cache again. An unexpected BUG_ON is triggered
   while loading cache mappings.

dmsetup resume cache

Kernel logs:

(snip)
------------[ cut here ]------------
kernel BUG at drivers/md/dm-cache-policy-smq.c:752!
Oops: invalid opcode: 0000 [#1] PREEMPT SMP KASAN NOPTI
CPU: 0 UID: 0 PID: 332 Comm: dmsetup Not tainted 6.13.4 #3
RIP: 0010:smq_load_mapping+0x3e5/0x570

Fix by disallowing resume operations for devices that failed the
initial attempt.

Signed-off-by: Ming-Hung Tsai <mtsai@redhat.com>
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-06-04 14:40:08 +02:00
Ming-Hung Tsai
c52ec00cb2 dm cache: fix potential out-of-bounds access on the first resume
commit c0ade5d989 upstream.

Out-of-bounds access occurs if the fast device is expanded unexpectedly
before the first-time resume of the cache table. This happens because
expanding the fast device requires reloading the cache table for
cache_create to allocate new in-core data structures that fit the new
size, and the check in cache_preresume is not performed during the
first resume, leading to the issue.

Reproduce steps:

1. prepare component devices:

dmsetup create cmeta --table "0 8192 linear /dev/sdc 0"
dmsetup create cdata --table "0 65536 linear /dev/sdc 8192"
dmsetup create corig --table "0 524288 linear /dev/sdc 262144"
dd if=/dev/zero of=/dev/mapper/cmeta bs=4k count=1 oflag=direct

2. load a cache table of 512 cache blocks, and deliberately expand the
   fast device before resuming the cache, making the in-core data
   structures inadequate.

dmsetup create cache --notable
dmsetup reload cache --table "0 524288 cache /dev/mapper/cmeta \
/dev/mapper/cdata /dev/mapper/corig 128 2 metadata2 writethrough smq 0"
dmsetup reload cdata --table "0 131072 linear /dev/sdc 8192"
dmsetup resume cdata
dmsetup resume cache

3. suspend the cache to write out the in-core dirty bitset and hint
   array, leading to out-of-bounds access to the dirty bitset at offset
   0x40:

dmsetup suspend cache

KASAN reports:

  BUG: KASAN: vmalloc-out-of-bounds in is_dirty_callback+0x2b/0x80
  Read of size 8 at addr ffffc90000085040 by task dmsetup/90

  (...snip...)
  The buggy address belongs to the virtual mapping at
   [ffffc90000085000, ffffc90000087000) created by:
   cache_ctr+0x176a/0x35f0

  (...snip...)
  Memory state around the buggy address:
   ffffc90000084f00: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
   ffffc90000084f80: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
  >ffffc90000085000: 00 00 00 00 00 00 00 00 f8 f8 f8 f8 f8 f8 f8 f8
                                             ^
   ffffc90000085080: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
   ffffc90000085100: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8

Fix by checking the size change on the first resume.

Signed-off-by: Ming-Hung Tsai <mtsai@redhat.com>
Fixes: f494a9c6b1 ("dm cache: cache shrinking support")
Cc: stable@vger.kernel.org
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Acked-by: Joe Thornber <thornber@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-11-14 13:15:15 +01:00
Ming-Hung Tsai
011450c2f9 dm cache: optimize dirty bit checking with find_next_bit when resizing
commit f484697e61 upstream.

When shrinking the fast device, dm-cache iteratively searches for a
dirty bit among the cache blocks to be dropped, which is less efficient.
Use find_next_bit instead, as it is twice as fast as the iterative
approach with test_bit.

Signed-off-by: Ming-Hung Tsai <mtsai@redhat.com>
Fixes: f494a9c6b1 ("dm cache: cache shrinking support")
Cc: stable@vger.kernel.org
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Acked-by: Joe Thornber <thornber@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-11-14 13:15:15 +01:00
Ming-Hung Tsai
56507203e1 dm cache: fix out-of-bounds access to the dirty bitset when resizing
commit 7922277197 upstream.

dm-cache checks the dirty bits of the cache blocks to be dropped when
shrinking the fast device, but an index bug in bitset iteration causes
out-of-bounds access.

Reproduce steps:

1. create a cache device of 1024 cache blocks (128 bytes dirty bitset)

dmsetup create cmeta --table "0 8192 linear /dev/sdc 0"
dmsetup create cdata --table "0 131072 linear /dev/sdc 8192"
dmsetup create corig --table "0 524288 linear /dev/sdc 262144"
dd if=/dev/zero of=/dev/mapper/cmeta bs=4k count=1 oflag=direct
dmsetup create cache --table "0 524288 cache /dev/mapper/cmeta \
/dev/mapper/cdata /dev/mapper/corig 128 2 metadata2 writethrough smq 0"

2. shrink the fast device to 512 cache blocks, triggering out-of-bounds
   access to the dirty bitset (offset 0x80)

dmsetup suspend cache
dmsetup reload cdata --table "0 65536 linear /dev/sdc 8192"
dmsetup resume cdata
dmsetup resume cache

KASAN reports:

  BUG: KASAN: vmalloc-out-of-bounds in cache_preresume+0x269/0x7b0
  Read of size 8 at addr ffffc900000f3080 by task dmsetup/131

  (...snip...)
  The buggy address belongs to the virtual mapping at
   [ffffc900000f3000, ffffc900000f5000) created by:
   cache_ctr+0x176a/0x35f0

  (...snip...)
  Memory state around the buggy address:
   ffffc900000f2f80: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
   ffffc900000f3000: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  >ffffc900000f3080: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
                     ^
   ffffc900000f3100: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
   ffffc900000f3180: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8

Fix by making the index post-incremented.

Signed-off-by: Ming-Hung Tsai <mtsai@redhat.com>
Fixes: f494a9c6b1 ("dm cache: cache shrinking support")
Cc: stable@vger.kernel.org
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Acked-by: Joe Thornber <thornber@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-11-14 13:15:15 +01:00
Ming-Hung Tsai
5a754d3c77 dm cache: fix flushing uninitialized delayed_work on cache_ctr error
commit 135496c208 upstream.

An unexpected WARN_ON from flush_work() may occur when cache creation
fails, caused by destroying the uninitialized delayed_work waker in the
error path of cache_create(). For example, the warning appears on the
superblock checksum error.

Reproduce steps:

dmsetup create cmeta --table "0 8192 linear /dev/sdc 0"
dmsetup create cdata --table "0 65536 linear /dev/sdc 8192"
dmsetup create corig --table "0 524288 linear /dev/sdc 262144"
dd if=/dev/urandom of=/dev/mapper/cmeta bs=4k count=1 oflag=direct
dmsetup create cache --table "0 524288 cache /dev/mapper/cmeta \
/dev/mapper/cdata /dev/mapper/corig 128 2 metadata2 writethrough smq 0"

Kernel logs:

(snip)
WARNING: CPU: 0 PID: 84 at kernel/workqueue.c:4178 __flush_work+0x5d4/0x890

Fix by pulling out the cancel_delayed_work_sync() from the constructor's
error path. This patch doesn't affect the use-after-free fix for
concurrent dm_resume and dm_destroy (commit 6a459d8edb ("dm cache: Fix
UAF in destroy()")) as cache_dtr is not changed.

Signed-off-by: Ming-Hung Tsai <mtsai@redhat.com>
Fixes: 6a459d8edb ("dm cache: Fix UAF in destroy()")
Cc: stable@vger.kernel.org
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Acked-by: Joe Thornber <thornber@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-11-14 13:15:15 +01:00
Ming-Hung Tsai
ffaf0f6eab dm cache: correct the number of origin blocks to match the target length
commit 235d2e739f upstream.

When creating a cache device, the actual size of the cache origin might
be greater than the specified cache target length. In such case, the
number of origin blocks should match the cache target length, not the
full size of the origin device, since access beyond the cache target is
not possible. This issue occurs when reducing the origin device size
using lvm, as lvreduce preloads the new cache table before resuming the
cache origin, which can result in incorrect sizes for the discard bitset
and smq hotspot blocks.

Reproduce steps:

1. create a cache device consists of 4096 origin blocks

dmsetup create cmeta --table "0 8192 linear /dev/sdc 0"
dmsetup create cdata --table "0 65536 linear /dev/sdc 8192"
dmsetup create corig --table "0 524288 linear /dev/sdc 262144"
dd if=/dev/zero of=/dev/mapper/cmeta bs=4k count=1 oflag=direct
dmsetup create cache --table "0 524288 cache /dev/mapper/cmeta \
/dev/mapper/cdata /dev/mapper/corig 128 2 metadata2 writethrough smq 0"

2. reduce the cache origin to 2048 oblocks, in lvreduce's approach

dmsetup reload corig --table "0 262144 linear /dev/sdc 262144"
dmsetup reload cache --table "0 262144 cache /dev/mapper/cmeta \
/dev/mapper/cdata /dev/mapper/corig 128 2 metadata2 writethrough smq 0"
dmsetup suspend cache
dmsetup suspend corig
dmsetup suspend cdata
dmsetup suspend cmeta
dmsetup resume corig
dmsetup resume cdata
dmsetup resume cmeta
dmsetup resume cache

3. shutdown the cache, and check the number of discard blocks in
   superblock. The value is expected to be 2048, but actually is 4096.

dmsetup remove cache corig cdata cmeta
dd if=/dev/sdc bs=1c count=8 skip=224 2>/dev/null | hexdump -e '1/8 "%u\n"'

Fix by correcting the origin_blocks initialization in cache_create and
removing the unused origin_sectors from struct cache_args accordingly.

Signed-off-by: Ming-Hung Tsai <mtsai@redhat.com>
Fixes: c6b4fcbad0 ("dm: add cache target")
Cc: stable@vger.kernel.org
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Acked-by: Joe Thornber <thornber@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-11-14 13:15:15 +01:00
Heinz Mauelshagen
83ee6b2729 dm: change "unsigned" to "unsigned int"
[ Upstream commit 86a3238c7b ]

Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
Stable-dep-of: f7b58a69fa ("dm: fix improper splitting for abnormal bios")
Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-04-13 16:55:17 +02:00
Mike Snitzer
3033f2e3cf dm cache: add cond_resched() to various workqueue loops
[ Upstream commit 76227f6dc8 ]

Otherwise on resource constrained systems these workqueues may be too
greedy.

Signed-off-by: Mike Snitzer <snitzer@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-03-10 09:34:01 +01:00
Mike Snitzer
a7e060c3ea dm cache: set needs_check flag after aborting metadata
commit 6b9973861c upstream.

Otherwise the commit that will be aborted will be associated with the
metadata objects that will be torn down.  Must write needs_check flag
to metadata with a reset block manager.

Found through code-inspection (and compared against dm-thin.c).

Cc: stable@vger.kernel.org
Fixes: 028ae9f76f ("dm cache: add fail io mode and needs_check flag")
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-01-07 11:11:46 +01:00
Luo Meng
6a3e412c2a dm cache: Fix UAF in destroy()
commit 6a459d8edb upstream.

Dm_cache also has the same UAF problem when dm_resume()
and dm_destroy() are concurrent.

Therefore, cancelling timer again in destroy().

Cc: stable@vger.kernel.org
Fixes: c6b4fcbad0 ("dm: add cache target")
Signed-off-by: Luo Meng <luomeng12@huawei.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-01-07 11:11:45 +01:00
Steven Lung
5c29e78473 dm cache: fix typo in 2 comment blocks
Replace neccessarily with necessarily.

Signed-off-by: Steven Lung <1030steven@gmail.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
2022-07-07 11:49:37 -04:00
Christoph Hellwig
70200574cc block: remove QUEUE_FLAG_DISCARD
Just use a non-zero max_discard_sectors as an indicator for discard
support, similar to what is done for write zeroes.

The only places where needs special attention is the RAID5 driver,
which must clear discard support for security reasons by default,
even if the default stacking rules would allow for it.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Acked-by: Christoph Böhmwalder <christoph.boehmwalder@linbit.com> [drbd]
Acked-by: Jan Höppner <hoeppner@linux.ibm.com> [s390]
Acked-by: Coly Li <colyli@suse.de> [bcache]
Acked-by: David Sterba <dsterba@suse.com> [btrfs]
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Link: https://lore.kernel.org/r/20220415045258.199825-25-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-04-17 19:49:59 -06:00
Mike Snitzer
69596f555b dm cache: use dm_submit_bio_remap
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2022-03-10 13:44:57 -05:00
Christoph Hellwig
385411ffba dm: stop using bdevname
Just use the %pg format specifier instead.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2022-03-02 12:15:54 -05:00
Christoph Hellwig
abfc426d1b block: pass a block_device to bio_clone_fast
Pass a block_device to bio_clone_fast and __bio_clone_fast and give
the functions more suitable names.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Mike Snitzer <snitzer@redhat.com>
Link: https://lore.kernel.org/r/20220202160109.108149-14-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-02-04 07:43:18 -07:00
Christoph Hellwig
3c4b455ef8 dm-cache: remove __remap_to_origin_clear_discard
Fold __remap_to_origin_clear_discard into the two callers to prepare
for bio cloning refactoring.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Mike Snitzer <snitzer@redhat.com>
Link: https://lore.kernel.org/r/20220202160109.108149-10-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-02-04 07:43:18 -07:00
Christoph Hellwig
6dcbb52cdd dm: use bdev_nr_sectors and bdev_nr_bytes instead of open coding them
Use the proper helpers to read the block device size.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Kees Cook <keescook@chromium.org>
Acked-by: Mike Snitzer <snitzer@redhat.com>
Link: https://lore.kernel.org/r/20211018101130.1838532-6-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-10-18 14:43:22 -06:00
Tushar Sugandhi
8ec456629d dm: update target status functions to support IMA measurement
For device mapper targets to take advantage of IMA's measurement
capabilities, the status functions for the individual targets need to be
updated to handle the status_type_t case for value STATUSTYPE_IMA.

Update status functions for the following target types, to log their
respective attributes to be measured using IMA.
 01. cache
 02. crypt
 03. integrity
 04. linear
 05. mirror
 06. multipath
 07. raid
 08. snapshot
 09. striped
 10. verity

For rest of the targets, handle the STATUSTYPE_IMA case by setting the
measurement buffer to NULL.

For IMA to measure the data on a given system, the IMA policy on the
system needs to be updated to have the following line, and the system
needs to be restarted for the measurements to take effect.

/etc/ima/ima-policy
 measure func=CRITICAL_DATA label=device-mapper template=ima-buf

The measurements will be reflected in the IMA logs, which are located at:

/sys/kernel/security/integrity/ima/ascii_runtime_measurements
/sys/kernel/security/integrity/ima/binary_runtime_measurements

These IMA logs can later be consumed by various attestation clients
running on the system, and send them to external services for attesting
the system.

The DM target data measured by IMA subsystem can alternatively
be queried from userspace by setting DM_IMA_MEASUREMENT_FLAG with
DM_TABLE_STATUS_CMD.

Signed-off-by: Tushar Sugandhi <tusharsu@linux.microsoft.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2021-08-10 13:34:23 -04:00
Mike Snitzer
dc4fa29fe4 dm io tracker: factor out IO tracker
Allow other code to use dm_io_tracker.

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2021-06-25 15:28:59 -04:00
Xu Wang
63508e38c1 dm cache: remove needless request_queue NULL pointer checks
Since commit ff9ea32381 ("block, bdi: an active gendisk always has a
request_queue associated with it") the request_queue pointer returned
from bdev_get_queue() shall never be NULL.

Signed-off-by: Xu Wang <vulab@iscas.ac.cn>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2021-03-26 14:53:42 -04:00
Zheng Yongjun
b77709237e dm cache: simplify the return expression of load_mapping()
Simplify the return expression.

Signed-off-by: Zheng Yongjun <zhengyongjun3@huawei.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2020-12-22 09:54:48 -05:00
Nick Desaulniers
35d2835d2a Revert "dm cache: fix arm link errors with inline"
This reverts commit 43aeaa2957.

Since commit 0bddd227f3 ("Documentation: update for gcc 4.9 requirement")
the minimum supported version of GCC is gcc-4.9. It's now safe to remove
this code.

Link: https://github.com/ClangBuiltLinux/linux/issues/427
Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
Acked-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2020-12-01 15:43:36 -05:00
Mike Snitzer
d4a512edcc dm: use dm_table_get_device_name() where appropriate in targets
dm_table_get_device_name() avoids calling dm_table_get_md() followed by
dm_device_name() -- saves intermediate dm_table_get_md() call.

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2020-09-29 16:33:08 -04:00
Christoph Hellwig
21cf866145 writeback: remove bdi->congested_fn
Except for pktdvd, the only places setting congested bits are file
systems that allocate their own backing_dev_info structures.  And
pktdvd is a deprecated driver that isn't useful in stack setup
either.  So remove the dead congested_fn stacking infrastructure.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Song Liu <song@kernel.org>
Acked-by: David Sterba <dsterba@suse.com>
[axboe: fixup unused variables in bcache/request.c]
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-07-08 17:20:46 -06:00
Christoph Hellwig
ed00aabd5e block: rename generic_make_request to submit_bio_noacct
generic_make_request has always been very confusingly misnamed, so rename
it to submit_bio_noacct to make it clear that it is submit_bio minus
accounting and a few checks.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-07-01 07:27:24 -06:00
Mike Snitzer
636be4241b dm: bump version of core and various targets
Changes made during the 5.6 cycle warrant bumping the version number
for DM core and the targets modified by this commit.

It should be noted that dm-thin, dm-crypt and dm-raid already had
their target version bumped during the 5.6 merge window.

Signed-off-by; Mike Snitzer <snitzer@redhat.com>
2020-03-03 11:10:21 -05:00
Mikulas Patocka
7cdf6a0aae dm cache: fix a crash due to incorrect work item cancelling
The crash can be reproduced by running the lvm2 testsuite test
lvconvert-thin-external-cache.sh for several minutes, e.g.:
  while :; do make check T=shell/lvconvert-thin-external-cache.sh; done

The crash happens in this call chain:
do_waker -> policy_tick -> smq_tick -> end_hotspot_period -> clear_bitset
-> memset -> __memset -- which accesses an invalid pointer in the vmalloc
area.

The work entry on the workqueue is executed even after the bitmap was
freed. The problem is that cancel_delayed_work doesn't wait for the
running work item to finish, so the work item can continue running and
re-submitting itself even after cache_postsuspend. In order to make sure
that the work item won't be running, we must use cancel_delayed_work_sync.

Also, change flush_workqueue to drain_workqueue, so that if some work item
submits itself or another work item, we are properly waiting for both of
them.

Fixes: c6b4fcbad0 ("dm: add cache target")
Cc: stable@vger.kernel.org # v3.9
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2020-02-27 12:00:52 -05:00
Mikulas Patocka
26b924b93c dm cache: replace spin_lock_irqsave with spin_lock_irq
If we are in a place where it is known that interrupts are enabled,
functions spin_lock_irq/spin_unlock_irq should be used instead of
spin_lock_irqsave/spin_unlock_irqrestore.

spin_lock_irq and spin_unlock_irq are faster because they don't need to
push and pop the flags register.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2019-11-05 14:53:04 -05:00
Mikulas Patocka
13bd677a47 dm cache: fix bugs when a GFP_NOWAIT allocation fails
GFP_NOWAIT allocation can fail anytime - it doesn't wait for memory being
available and it fails if the mempool is exhausted and there is not enough
memory.

If we go down this path:
  map_bio -> mg_start -> alloc_migration -> mempool_alloc(GFP_NOWAIT)
we can see that map_bio() doesn't check the return value of mg_start(),
and the bio is leaked.

If we go down this path:
  map_bio -> mg_start -> mg_lock_writes -> alloc_prison_cell ->
  dm_bio_prison_alloc_cell_v2 -> mempool_alloc(GFP_NOWAIT) ->
  mg_lock_writes -> mg_complete
the bio is ended with an error - it is unacceptable because it could
cause filesystem corruption if the machine ran out of memory
temporarily.

Change GFP_NOWAIT to GFP_NOIO, so that the mempool code will properly
wait until memory becomes available. mempool_alloc with GFP_NOIO can't
fail, so remove the code paths that deal with allocation failure.

Cc: stable@vger.kernel.org
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2019-10-17 11:13:50 -04:00
Mike Snitzer
de7180ff90 dm cache: add support for discard passdown to the origin device
DM cache now defaults to passing discards down to the origin device.
User may disable this using the "no_discard_passdown" feature when
creating the cache device.

If the cache's underlying origin device doesn't support discards then
passdown is disabled (with warning).  Similarly, if the underlying
origin device's max_discard_sectors is less than a cache block discard
passdown will be disabled (this is required because sizing of the cache
internal discard bitset depends on it).

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2019-03-05 14:53:52 -05:00
Mike Snitzer
61697a6abd dm: eliminate 'split_discard_bios' flag from DM target interface
There is no need to have DM core split discards on behalf of a DM target
now that blk_queue_split() handles splitting discards based on the
queue_limits.  A DM target just needs to set max_discard_sectors,
discard_granularity, etc, in queue_limits.

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2019-02-20 23:24:55 -05:00
Shenghui Wang
c7cd55504a dm cache: destroy migration_cache if cache target registration failed
Commit 7e6358d244 ("dm: fix various targets to dm_register_target
after module __init resources created") inadvertently introduced this
bug when it moved dm_register_target() after the call to KMEM_CACHE().

Fixes: 7e6358d244 ("dm: fix various targets to dm_register_target after module __init resources created")
Cc: stable@vger.kernel.org
Signed-off-by: Shenghui Wang <shhuiw@foxmail.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2018-10-09 13:53:03 -04:00
Mike Snitzer
5d07384a66 dm cache: fix resize crash if user doesn't reload cache table
A reload of the cache's DM table is needed during resize because
otherwise a crash will occur when attempting to access smq policy
entries associated with the portion of the cache that was recently
extended.

The reason is cache-size based data structures in the policy will not be
resized, the only way to safely extend the cache is to allow for a
proper cache policy initialization that occurs when the cache table is
loaded.  For example the smq policy's space_init(), init_allocator(),
calc_hotspot_params() must be sized based on the extended cache size.

The fix for this is to disallow cache resizes of this pattern:
1) suspend "cache" target's device
2) resize the fast device used for the cache
3) resume "cache" target's device

Instead, the last step must be a full reload of the cache's DM table.

Fixes: 66a636356 ("dm cache: add stochastic-multi-queue (smq) policy")
Cc: stable@vger.kernel.org
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2018-10-04 15:20:52 -04:00
Mike Snitzer
7209049d40 dm kcopyd: return void from dm_kcopyd_copy()
dm_kcopyd_copy() only ever returns 0 so there is no need for callers to
account for possible failure.  Same goes for dm_kcopyd_zero().

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2018-07-31 17:33:21 -04:00
John Pittman
af9313c32c dm cache: only allow a single io_mode cache feature to be requested
More than one io_mode feature can be requested when creating a dm cache
device (as is: last one wins).  The io_mode selections are incompatible
with one another, we should force them to be selected exclusively.  Add
a counter to check for more than one io_mode selection.

Fixes: 629d0a8a1a ("dm cache metadata: add "metadata2" feature")
Signed-off-by: John Pittman <jpittman@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2018-07-27 15:24:18 -04:00
Mike Snitzer
72d711c876 dm: adjust structure members to improve alignment
Eliminate most holes in DM data structures that were modified by
commit 6f1c819c21 ("dm: convert to bioset_init()/mempool_init()").
Also prevent structure members from unnecessarily spanning cache
lines.

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2018-06-08 11:53:14 -04:00
Kent Overstreet
6f1c819c21 dm: convert to bioset_init()/mempool_init()
Convert dm to embedded bio sets.

Acked-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-05-30 15:33:32 -06:00
Mike Snitzer
1eb5fa849f dm: allow targets to return output from messages they are sent
Could be useful for a target to return stats or other information.
If a target does DMEMIT() anything to @result from its .message method
then it must return 1 to the caller.

Signed-off-By: Mike Snitzer <snitzer@redhat.com>
2018-04-03 15:04:10 -04:00
monty_pavel@sina.com
7e6358d244 dm: fix various targets to dm_register_target after module __init resources created
A NULL pointer is seen if two concurrent "vgchange -ay -K <vg name>"
processes race to load the dm-thin-pool module:

 PID: 25992 TASK: ffff883cd7d23500 CPU: 4 COMMAND: "vgchange"
  #0 [ffff883cd743d600] machine_kexec at ffffffff81038fa9
  0000001 [ffff883cd743d660] crash_kexec at ffffffff810c5992
  0000002 [ffff883cd743d730] oops_end at ffffffff81515c90
  0000003 [ffff883cd743d760] no_context at ffffffff81049f1b
  0000004 [ffff883cd743d7b0] __bad_area_nosemaphore at ffffffff8104a1a5
  0000005 [ffff883cd743d800] bad_area at ffffffff8104a2ce
  0000006 [ffff883cd743d830] __do_page_fault at ffffffff8104aa6f
  0000007 [ffff883cd743d950] do_page_fault at ffffffff81517bae
  0000008 [ffff883cd743d980] page_fault at ffffffff81514f95
     [exception RIP: kmem_cache_alloc+108]
     RIP: ffffffff8116ef3c RSP: ffff883cd743da38 RFLAGS: 00010046
     RAX: 0000000000000004 RBX: ffffffff81121b90 RCX: ffff881bf1e78cc0
     RDX: 0000000000000000 RSI: 00000000000000d0 RDI: 0000000000000000
     RBP: ffff883cd743da68 R8: ffff881bf1a4eb00 R9: 0000000080042000
     R10: 0000000000002000 R11: 0000000000000000 R12: 00000000000000d0
     R13: 0000000000000000 R14: 00000000000000d0 R15: 0000000000000246
     ORIG_RAX: ffffffffffffffff CS: 0010 SS: 0018
  0000009 [ffff883cd743da70] mempool_alloc_slab at ffffffff81121ba5
 0000010 [ffff883cd743da80] mempool_create_node at ffffffff81122083
 0000011 [ffff883cd743dad0] mempool_create at ffffffff811220f4
 0000012 [ffff883cd743dae0] pool_ctr at ffffffffa08de049 [dm_thin_pool]
 0000013 [ffff883cd743dbd0] dm_table_add_target at ffffffffa0005f2f [dm_mod]
 0000014 [ffff883cd743dc30] table_load at ffffffffa0008ba9 [dm_mod]
 0000015 [ffff883cd743dc90] ctl_ioctl at ffffffffa0009dc4 [dm_mod]

The race results in a NULL pointer because:

Process A (vgchange -ay -K):
 	a. send DM_LIST_VERSIONS_CMD ioctl;
 	b. pool_target not registered;
 	c. modprobe dm_thin_pool and wait until end.

Process B (vgchange -ay -K):
 	a. send DM_LIST_VERSIONS_CMD ioctl;
 	b. pool_target registered;
 	c. table_load->dm_table_add_target->pool_ctr;
 	d. _new_mapping_cache is NULL and panic.
Note:
 	1. process A and process B are two concurrent processes.
 	2. pool_target can be detected by process B but
 	_new_mapping_cache initialization has not ended.

To fix dm-thin-pool, and other targets (cache, multipath, and snapshot)
with the same problem, simply dm_register_target() after all resources
created during module init (as labelled with __init) are finished.

Cc: stable@vger.kernel.org
Signed-off-by: monty <monty_pavel@sina.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2017-12-04 10:23:10 -05:00
Mike Snitzer
ef7afb3656 dm cache: lift common migration preparation code to alloc_migration()
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2017-11-10 15:45:07 -05:00
Joe Thornber
ede6507d67 dm cache: remove usused deferred_cells member from struct cache
Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2017-11-10 15:45:06 -05:00
Mike Snitzer
693b960ea8 dm cache: simplify get_per_bio_data() by removing data_size argument
There is only one per_bio_data size now that writethrough-specific data
was removed from the per_bio_data structure.

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2017-11-10 15:44:49 -05:00
Mike Snitzer
9958f1d9a0 dm cache: remove all obsolete writethrough-specific code
Now that the writethrough code is much simpler there is no need to track
so much state or cascade bio submission (as was done, via
writethrough_endio(), to issue origin then cache IO in series).

As such the obsolete writethrough list and workqueue is also removed.

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2017-11-10 15:44:48 -05:00
Mike Snitzer
2df3bae9a6 dm cache: submit writethrough writes in parallel to origin and cache
Discontinue issuing writethrough write IO in series to the origin and
then cache.

Use bio_clone_fast() to create a new origin clone bio that will be
mapped to the origin device and then bio_chain() it to the bio that gets
remapped to the cache device.  The origin clone bio does _not_ have a
copy of the per_bio_data -- as such check_if_tick_bio_needed() will not
be called.

The cache bio (parent bio) will not complete until the origin bio has
completed -- this fulfills bio_clone_fast()'s requirements as well as
the requirement to not complete the original IO until the write IO has
completed to both the origin and cache device.

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2017-11-10 15:44:47 -05:00
Mike Snitzer
8e3c382777 dm cache: pass cache structure to mode functions
No functional changes, just a bit cleaner than passing cache_features
structure.

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2017-11-10 15:44:42 -05:00
Joe Thornber
d1260e2a3f dm cache: fix race condition in the writeback mode overwrite_bio optimisation
When a DM cache in writeback mode moves data between the slow and fast
device it can often avoid a copy if the triggering bio either:

i) covers the whole block (no point copying if we're about to overwrite it)
ii) the migration is a promotion and the origin block is currently discarded

Prior to this fix there was a race with case (ii).  The discard status
was checked with a shared lock held (rather than exclusive).  This meant
another bio could run in parallel and write data to the origin, removing
the discard state.  After the promotion the parallel write would have
been lost.

With this fix the discard status is re-checked once the exclusive lock
has been aquired.  If the block is no longer discarded it falls back to
the slower full copy path.

Fixes: b29d4986d ("dm cache: significant rework to leverage dm-bio-prison-v2")
Cc: stable@vger.kernel.org # v4.12+
Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2017-11-10 15:43:39 -05:00
Linus Torvalds
dff4d1f6fe - Some request-based DM core and DM multipath fixes and cleanups
- Constify a few variables in DM core and DM integrity
 
 - Add bufio optimization and checksum failure accounting to DM integrity
 
 - Fix DM integrity to avoid checking integrity of failed reads
 
 - Fix DM integrity to use init_completion
 
 - A couple DM log-writes target fixes
 
 - Simplify DAX flushing by eliminating the unnecessary flush abstraction
   that was stood up for DM's use.
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Merge tag 'for-4.14/dm-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm

Pull device mapper updates from Mike Snitzer:

 - Some request-based DM core and DM multipath fixes and cleanups

 - Constify a few variables in DM core and DM integrity

 - Add bufio optimization and checksum failure accounting to DM
   integrity

 - Fix DM integrity to avoid checking integrity of failed reads

 - Fix DM integrity to use init_completion

 - A couple DM log-writes target fixes

 - Simplify DAX flushing by eliminating the unnecessary flush
   abstraction that was stood up for DM's use.

* tag 'for-4.14/dm-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm:
  dax: remove the pmem_dax_ops->flush abstraction
  dm integrity: use init_completion instead of COMPLETION_INITIALIZER_ONSTACK
  dm integrity: make blk_integrity_profile structure const
  dm integrity: do not check integrity for failed read operations
  dm log writes: fix >512b sectorsize support
  dm log writes: don't use all the cpu while waiting to log blocks
  dm ioctl: constify ioctl lookup table
  dm: constify argument arrays
  dm integrity: count and display checksum failures
  dm integrity: optimize writing dm-bufio buffers that are partially changed
  dm rq: do not update rq partially in each ending bio
  dm rq: make dm-sq requeuing behavior consistent with dm-mq behavior
  dm mpath: complain about unsupported __multipath_map_bio() return values
  dm mpath: avoid that building with W=1 causes gcc 7 to complain about fall-through
2017-09-14 13:43:16 -07:00
Eric Biggers
5916a22b83 dm: constify argument arrays
The arrays of 'struct dm_arg' are never modified by the device-mapper
core, so constify them so that they are placed in .rodata.

(Exception: the args array in dm-raid cannot be constified because it is
allocated on the stack and modified.)

Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2017-08-28 11:47:18 -04:00
Christoph Hellwig
74d46992e0 block: replace bi_bdev with a gendisk pointer and partitions index
This way we don't need a block_device structure to submit I/O.  The
block_device has different life time rules from the gendisk and
request_queue and is usually only available when the block device node
is open.  Other callers need to explicitly create one (e.g. the lightnvm
passthrough code, or the new nvme multipathing code).

For the actual I/O path all that we need is the gendisk, which exists
once per block device.  But given that the block layer also does
partition remapping we additionally need a partition index, which is
used for said remapping in generic_make_request.

Note that all the block drivers generally want request_queue or
sometimes the gendisk, so this removes a layer of indirection all
over the stack.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2017-08-23 12:49:55 -06:00
Christoph Hellwig
4e4cbee93d block: switch bios to blk_status_t
Replace bi_error with a new bi_status to allow for a clear conversion.
Note that device mapper overloaded bi_error with a private value, which
we'll have to keep arround at least for now and thus propagate to a
proper blk_status_t value.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
2017-06-09 09:27:32 -06:00