We must have some way of letting a storage device driver know what
encryption context it should use for en/decrypting a request. However,
it's the upper layers (like the filesystem/fscrypt) that know about and
manages encryption contexts. As such, when the upper layer submits a bio
to the block layer, and this bio eventually reaches a device driver with
support for inline encryption, the device driver will need to have been
told the encryption context for that bio.
We want to communicate the encryption context from the upper layer to the
storage device along with the bio, when the bio is submitted to the block
layer. To do this, we add a struct bio_crypt_ctx to struct bio, which can
represent an encryption context (note that we can't use the bi_private
field in struct bio to do this because that field does not function to pass
information across layers in the storage stack). We also introduce various
functions to manipulate the bio_crypt_ctx and make the bio/request merging
logic aware of the bio_crypt_ctx.
We also make changes to blk-mq to make it handle bios with encryption
contexts. blk-mq can merge many bios into the same request. These bios need
to have contiguous data unit numbers (the necessary changes to blk-merge
are also made to ensure this) - as such, it suffices to keep the data unit
number of just the first bio, since that's all a storage driver needs to
infer the data unit number to use for each data block in each bio in a
request. blk-mq keeps track of the encryption context to be used for all
the bios in a request with the request's rq_crypt_ctx. When the first bio
is added to an empty request, blk-mq will program the encryption context
of that bio into the request_queue's keyslot manager, and store the
returned keyslot in the request's rq_crypt_ctx. All the functions to
operate on encryption contexts are in blk-crypto.c.
Upper layers only need to call bio_crypt_set_ctx with the encryption key,
algorithm and data_unit_num; they don't have to worry about getting a
keyslot for each encryption context, as blk-mq/blk-crypto handles that.
Blk-crypto also makes it possible for request-based layered devices like
dm-rq to make use of inline encryption hardware by cloning the
rq_crypt_ctx and programming a keyslot in the new request_queue when
necessary.
Note that any user of the block layer can submit bios with an
encryption context, such as filesystems, device-mapper targets, etc.
Signed-off-by: Satya Tangirala <satyat@google.com>
Reviewed-by: Eric Biggers <ebiggers@google.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Call blk_mq_make_request when no ->make_request_fn is set. This is
safe now that blk_alloc_queue always sets up the pointer for make_request
based drivers. This avoids an indirect call in the blk-mq driver I/O
fast path, which is rather expensive due to spectre mitigations.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
- Add support for region alignment configuration and enforcement to
fix compatibility across architectures and PowerPC page size
configurations.
- Introduce 'zero_page_range' as a dax operation. This facilitates
filesystem-dax operation without a block-device.
- Introduce phys_to_target_node() to facilitate drivers that want to
know resulting numa node if a given reserved address range was
onlined.
- Advertise a persistence-domain for of_pmem and papr_scm. The
persistence domain indicates where cpu-store cycles need to reach in
the platform-memory subsystem before the platform will consider them
power-fail protected.
- Promote numa_map_to_online_node() to a cross-kernel generic facility.
- Save x86 numa information to allow for node-id lookups for reserved
memory ranges, deploy that capability for the e820-pmem driver.
- Pick up some miscellaneous minor fixes, that missed v5.6-final,
including a some smatch reports in the ioctl path and some unit test
compilation fixups.
- Fixup some flexible-array declarations.
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Merge tag 'libnvdimm-for-5.7' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm
Pull libnvdimm and dax updates from Dan Williams:
"There were multiple touches outside of drivers/nvdimm/ this round to
add cross arch compatibility to the devm_memremap_pages() interface,
enhance numa information for persistent memory ranges, and add a
zero_page_range() dax operation.
This cycle I switched from the patchwork api to Konstantin's b4 script
for collecting tags (from x86, PowerPC, filesystem, and device-mapper
folks), and everything looks to have gone ok there. This has all
appeared in -next with no reported issues.
Summary:
- Add support for region alignment configuration and enforcement to
fix compatibility across architectures and PowerPC page size
configurations.
- Introduce 'zero_page_range' as a dax operation. This facilitates
filesystem-dax operation without a block-device.
- Introduce phys_to_target_node() to facilitate drivers that want to
know resulting numa node if a given reserved address range was
onlined.
- Advertise a persistence-domain for of_pmem and papr_scm. The
persistence domain indicates where cpu-store cycles need to reach
in the platform-memory subsystem before the platform will consider
them power-fail protected.
- Promote numa_map_to_online_node() to a cross-kernel generic
facility.
- Save x86 numa information to allow for node-id lookups for reserved
memory ranges, deploy that capability for the e820-pmem driver.
- Pick up some miscellaneous minor fixes, that missed v5.6-final,
including a some smatch reports in the ioctl path and some unit
test compilation fixups.
- Fixup some flexible-array declarations"
* tag 'libnvdimm-for-5.7' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm: (29 commits)
dax: Move mandatory ->zero_page_range() check in alloc_dax()
dax,iomap: Add helper dax_iomap_zero() to zero a range
dax: Use new dax zero page method for zeroing a page
dm,dax: Add dax zero_page_range operation
s390,dcssblk,dax: Add dax zero_page_range operation to dcssblk driver
dax, pmem: Add a dax operation zero_page_range
pmem: Add functions for reading/writing page to/from pmem
libnvdimm: Update persistence domain value for of_pmem and papr_scm device
tools/test/nvdimm: Fix out of tree build
libnvdimm/region: Fix build error
libnvdimm/region: Replace zero-length array with flexible-array member
libnvdimm/label: Replace zero-length array with flexible-array member
ACPI: NFIT: Replace zero-length array with flexible-array member
libnvdimm/region: Introduce an 'align' attribute
libnvdimm/region: Introduce NDD_LABELING
libnvdimm/namespace: Enforce memremap_compat_align()
libnvdimm/pfn: Prevent raw mode fallback if pfn-infoblock valid
libnvdimm: Out of bounds read in __nd_ioctl()
acpi/nfit: improve bounds checking for 'func'
mm/memremap_pages: Introduce memremap_compat_align()
...
This reverts commit effd58c95f.
blk_queue_split() is causing excessive IO splitting -- because
blk_max_size_offset() depends on 'chunk_sectors' limit being set and
if it isn't (as is the case for DM targets!) it falls back to
splitting on a 'max_sectors' boundary regardless of offset.
"Fix" this by reverting back to _not_ using blk_queue_split() in
dm_process_bio() for normal IO (reads and writes). Long-term fix is
still TBD but it should focus on training blk_max_size_offset() to
call into a DM provided hook (to call DM's max_io_len()).
Test results from simple misaligned IO test on 4-way dm-striped device
with chunksize of 128K and stripesize of 512K:
xfs_io -d -c 'pread -b 2m 224s 4072s' /dev/mapper/stripe_dev
before this revert:
253,0 21 1 0.000000000 2206 Q R 224 + 4072 [xfs_io]
253,0 21 2 0.000008267 2206 X R 224 / 480 [xfs_io]
253,0 21 3 0.000010530 2206 X R 224 / 256 [xfs_io]
253,0 21 4 0.000027022 2206 X R 480 / 736 [xfs_io]
253,0 21 5 0.000028751 2206 X R 480 / 512 [xfs_io]
253,0 21 6 0.000033323 2206 X R 736 / 992 [xfs_io]
253,0 21 7 0.000035130 2206 X R 736 / 768 [xfs_io]
253,0 21 8 0.000039146 2206 X R 992 / 1248 [xfs_io]
253,0 21 9 0.000040734 2206 X R 992 / 1024 [xfs_io]
253,0 21 10 0.000044694 2206 X R 1248 / 1504 [xfs_io]
253,0 21 11 0.000046422 2206 X R 1248 / 1280 [xfs_io]
253,0 21 12 0.000050376 2206 X R 1504 / 1760 [xfs_io]
253,0 21 13 0.000051974 2206 X R 1504 / 1536 [xfs_io]
253,0 21 14 0.000055881 2206 X R 1760 / 2016 [xfs_io]
253,0 21 15 0.000057462 2206 X R 1760 / 1792 [xfs_io]
253,0 21 16 0.000060999 2206 X R 2016 / 2272 [xfs_io]
253,0 21 17 0.000062489 2206 X R 2016 / 2048 [xfs_io]
253,0 21 18 0.000066133 2206 X R 2272 / 2528 [xfs_io]
253,0 21 19 0.000067507 2206 X R 2272 / 2304 [xfs_io]
253,0 21 20 0.000071136 2206 X R 2528 / 2784 [xfs_io]
253,0 21 21 0.000072764 2206 X R 2528 / 2560 [xfs_io]
253,0 21 22 0.000076185 2206 X R 2784 / 3040 [xfs_io]
253,0 21 23 0.000077486 2206 X R 2784 / 2816 [xfs_io]
253,0 21 24 0.000080885 2206 X R 3040 / 3296 [xfs_io]
253,0 21 25 0.000082316 2206 X R 3040 / 3072 [xfs_io]
253,0 21 26 0.000085788 2206 X R 3296 / 3552 [xfs_io]
253,0 21 27 0.000087096 2206 X R 3296 / 3328 [xfs_io]
253,0 21 28 0.000093469 2206 X R 3552 / 3808 [xfs_io]
253,0 21 29 0.000095186 2206 X R 3552 / 3584 [xfs_io]
253,0 21 30 0.000099228 2206 X R 3808 / 4064 [xfs_io]
253,0 21 31 0.000101062 2206 X R 3808 / 3840 [xfs_io]
253,0 21 32 0.000104956 2206 X R 4064 / 4096 [xfs_io]
253,0 21 33 0.001138823 0 C R 4096 + 200 [0]
after this revert:
253,0 18 1 0.000000000 4430 Q R 224 + 3896 [xfs_io]
253,0 18 2 0.000018359 4430 X R 224 / 256 [xfs_io]
253,0 18 3 0.000028898 4430 X R 256 / 512 [xfs_io]
253,0 18 4 0.000033535 4430 X R 512 / 768 [xfs_io]
253,0 18 5 0.000065684 4430 X R 768 / 1024 [xfs_io]
253,0 18 6 0.000091695 4430 X R 1024 / 1280 [xfs_io]
253,0 18 7 0.000098494 4430 X R 1280 / 1536 [xfs_io]
253,0 18 8 0.000114069 4430 X R 1536 / 1792 [xfs_io]
253,0 18 9 0.000129483 4430 X R 1792 / 2048 [xfs_io]
253,0 18 10 0.000136759 4430 X R 2048 / 2304 [xfs_io]
253,0 18 11 0.000152412 4430 X R 2304 / 2560 [xfs_io]
253,0 18 12 0.000160758 4430 X R 2560 / 2816 [xfs_io]
253,0 18 13 0.000183385 4430 X R 2816 / 3072 [xfs_io]
253,0 18 14 0.000190797 4430 X R 3072 / 3328 [xfs_io]
253,0 18 15 0.000197667 4430 X R 3328 / 3584 [xfs_io]
253,0 18 16 0.000218751 4430 X R 3584 / 3840 [xfs_io]
253,0 18 17 0.000226005 4430 X R 3840 / 4096 [xfs_io]
253,0 18 18 0.000250404 4430 Q R 4120 + 176 [xfs_io]
253,0 18 19 0.000847708 0 C R 4096 + 24 [0]
253,0 18 20 0.000855783 0 C R 4120 + 176 [0]
Fixes: effd58c95f ("dm: always call blk_queue_split() in dm_process_bio()")
Cc: stable@vger.kernel.org
Reported-by: Andreas Gruenbacher <agruenba@redhat.com>
Tested-by: Barry Marson <bmarson@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
zero_page_range() dax operation is mandatory for dax devices. Right now
that check happens in dax_zero_page_range() function. Dan thinks that's
too late and its better to do the check earlier in alloc_dax().
I also modified alloc_dax() to return pointer with error code in it in
case of failure. Right now it returns NULL and caller assumes failure
happened due to -ENOMEM. But with this ->zero_page_range() check, I
need to return -EINVAL instead.
Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Link: https://lore.kernel.org/r/20200401161125.GB9398@redhat.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
This patch adds support for dax zero_page_range operation to dm targets.
Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Acked-by: Mike Snitzer <snitzer@redhat.com>
Link: https://lore.kernel.org/r/20200228163456.1587-5-vgoyal@redhat.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Current make_request based drivers use either blk_alloc_queue_node or
blk_alloc_queue to allocate a queue, and then set up the make_request_fn
function pointer and a few parameters using the blk_queue_make_request
helper. Simplify this by passing the make_request pointer to
blk_alloc_queue, and while at it merge the _node variant into the main
helper by always passing a node_id, and remove the superfluous gfp_mask
parameter. A lower-level __blk_alloc_queue is kept for the blk-mq case.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
These macros are just used by a few files. Move them out of genhd.h,
which is included everywhere into a new standalone header.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
We neither assign congested_fn for requested-based blk-mq device nor
implement it correctly. So fix both.
Also, remove incorrect comment from dm_init_normal_md_queue and rename
it to dm_init_congested_fn.
Fixes: 4aa9c692e0 ("bdi: separate out congested state into a separate struct")
Cc: stable@vger.kernel.org
Signed-off-by: Hou Tao <houtao1@huawei.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
The function dm_suspended returns true if the target is suspended.
However, when the target is being suspended during unload, it returns
false.
An example where this is a problem: the test "!dm_suspended(wc->ti)" in
writecache_writeback is not sufficient, because dm_suspended returns
zero while writecache_suspend is in progress. As is, without an
enhanced dm_suspended, simply switching from flush_workqueue to
drain_workqueue still emits warnings:
workqueue writecache-writeback: drain_workqueue() isn't complete after 10 tries
workqueue writecache-writeback: drain_workqueue() isn't complete after 100 tries
workqueue writecache-writeback: drain_workqueue() isn't complete after 200 tries
workqueue writecache-writeback: drain_workqueue() isn't complete after 300 tries
workqueue writecache-writeback: drain_workqueue() isn't complete after 400 tries
writecache_suspend calls flush_workqueue(wc->writeback_wq) - this function
flushes the current work. However, the workqueue may re-queue itself and
flush_workqueue doesn't wait for re-queued works to finish. Because of
this - the function writecache_writeback continues execution after the
device was suspended and then concurrently with writecache_dtr, causing
a crash in writecache_writeback.
We must use drain_workqueue - that waits until the work and all re-queued
works finish.
As a prereq for switching to drain_workqueue, this commit fixes
dm_suspended to return true after the presuspend hook and before the
postsuspend hook - just like during a normal suspend. It allows
simplifying the dm-integrity and dm-writecache targets so that they
don't have to maintain suspended flags on their own.
With this change use of drain_workqueue() can be used effectively. This
change was tested with the lvm2 testsuite and cryptsetup testsuite and
the are no regressions.
Fixes: 48debafe4f ("dm: add writecache target")
Cc: stable@vger.kernel.org # 4.18+
Reported-by: Corey Marthaler <cmarthal@redhat.com>
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Move blk_queue_make_request() to dm.c:alloc_dev() so that
q->make_request_fn is never NULL during the lifetime of a DM device
(even one that is created without a DM table).
Otherwise generic_make_request() will crash simply by doing:
dmsetup create -n test
mount /dev/dm-N /mnt
While at it, move ->congested_data initialization out of
dm.c:alloc_dev() and into the bio-based specific init method.
Reported-by: Stefan Bader <stefan.bader@canonical.com>
BugLink: https://bugs.launchpad.net/bugs/1860231
Fixes: ff36ab3458 ("dm: remove request-based logic from make_request_fn wrapper")
Depends-on: c12c9a3c38 ("dm: various cleanups to md->queue initialization code")
Cc: stable@vger.kernel.org
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Avoid the need to allocate a potentially large array of struct blk_zone
in the block layer by switching the ->report_zones method interface to
a callback model. Now the caller simply supplies a callback that is
executed on each reported zone, and private data for it.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Shin'ichiro Kawasaki <shinichiro.kawasaki@wdc.com>
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
No known partitioning tool supports zoned block devices, especially the
host managed flavor with strong sequential write constraints.
Furthermore, there are also no known user nor use cases for partitioned
zoned block devices.
This patch removes partition device creation for zoned block devices,
which allows simplifying the processing of zone commands for zoned
block devices. A warning is added if a partition table is found on the
device.
For report zones operations no zone sector information remapping is
necessary anymore, simplifying the code. Of note is that remapping of
zone reports for DM targets is still necessary as done by
dm_remap_zone_report().
Similarly, remaping of a zone reset bio is not necessary anymore.
Testing for the applicability of the zone reset all request also becomes
simpler and only needs to check that the number of sectors of the
requested zone range is equal to the disk capacity.
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
All kernel users of blkdev_report_zones() as well as applications use
through ioctl(BLKZONEREPORT) expect to potentially get less zone
descriptors than requested. As such, the use of the internal report
zones command execution loop implemented by blk_report_zones() is
not necessary and can even be harmful to performance by causing the
execution of inefficient small zones report command to service the
reminder of a requested zone array.
This patch removes blk_report_zones(), simplifying the code. Also
remove a now incorrect comment in dm_blk_report_zones().
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Javier Gonzalez <javier@javigon.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Implement REQ_OP_ZONE_OPEN, REQ_OP_ZONE_CLOSE and REQ_OP_ZONE_FINISH
support to allow explicit control of zone states.
Contains contributions from Matias Bjorling, Hans Holmberg and
Damien Le Moal.
Acked-by: Mike Snitzer <snitzer@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Ajay Joshi <ajay.joshi@wdc.com>
Signed-off-by: Matias Bjorling <matias.bjorling@wdc.com>
Signed-off-by: Hans Holmberg <hans.holmberg@wdc.com>
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Currently, if we pass too high sector number to dm_table_find_target, it
returns zeroed dm_target structure and callers test if the structure is
zeroed with the macro dm_target_is_valid.
However, returning NULL is common practice to indicate errors.
This patch refactors the dm code, so that dm_table_find_target returns
NULL and its callers test the returned value for NULL. The macro
dm_target_is_valid is deleted. In alloc_targets, we no longer allocate an
extra zeroed target.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
persistent memory device that allows a guest VM to use DAX mechanisms to
access a host-file with host-page-cache. It arranges for MAP_SYNC to
be disabled and instead triggers a host fsync() when a 'write-cache
flush' command is sent to the virtual disk device.
- Miscellaneous small fixups.
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Merge tag 'libnvdimm-for-5.3' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm
Pull libnvdimm updates from Dan Williams:
"Primarily just the virtio_pmem driver:
- virtio_pmem
The new virtio_pmem facility introduces a paravirtualized
persistent memory device that allows a guest VM to use DAX
mechanisms to access a host-file with host-page-cache. It arranges
for MAP_SYNC to be disabled and instead triggers a host fsync()
when a 'write-cache flush' command is sent to the virtual disk
device.
- Miscellaneous small fixups"
* tag 'libnvdimm-for-5.3' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm:
virtio_pmem: fix sparse warning
xfs: disable map_sync for async flush
ext4: disable map_sync for async flush
dax: check synchronous mapping is supported
dm: enable synchronous dax
libnvdimm: add dax_dev sync flag
virtio-pmem: Add virtio pmem driver
libnvdimm: nd_region flush callback support
libnvdimm, namespace: Drop uuid_t implementation detail
Only GFP_KERNEL and GFP_NOIO are used with blkdev_report_zones(). In
preparation of using vmalloc() for large report buffer and zone array
allocations used by this function, remove its "gfp_t gfp_mask" argument
and rely on the caller context to use memalloc_noio_save/restore() where
necessary (block layer zone revalidation and dm-zoned I/O error path).
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This patch sets dax device 'DAXDEV_SYNC' flag if all the target
devices of device mapper support synchrononous DAX. If device
mapper consists of both synchronous and asynchronous dax devices,
we don't set 'DAXDEV_SYNC' flag.
'dm_table_supports_dax' is refactored to pass 'iterate_devices_fn'
as argument so that the callers can pass the appropriate functions.
Suggested-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Pankaj Gupta <pagupta@redhat.com>
Reviewed-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
This patch adds 'DAXDEV_SYNC' flag which is set
for nd_region doing synchronous flush. This later
is used to disable MAP_SYNC functionality for
ext4 & xfs filesystem for devices don't support
synchronous flush.
Signed-off-by: Pankaj Gupta <pagupta@redhat.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Commit 61697a6abd ("dm: eliminate 'split_discard_bios' flag from DM
target interface") incorrectly removed code from
__send_changing_extent_only() that is required to impose a per-target IO
boundary on IO that exceeds max_io_len_target_boundary(). Otherwise
"special" IO (e.g. DISCARD, WRITE SAME, WRITE ZEROES) can write beyond
where allowed.
Fix this by restoring the max_io_len_target_boundary() limit in
__send_changing_extent_only()
Fixes: 61697a6abd ("dm: eliminate 'split_discard_bios' flag from DM target interface")
Cc: stable@vger.kernel.org # 5.1+
Signed-off-by: Michael Lass <bevan@bi-co.net>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Pankaj reports that starting with commit ad428cdb52 "dax: Check the
end of the block-device capacity with dax_direct_access()" device-mapper
no longer allows dax operation. This results from the stricter checks in
__bdev_dax_supported() that validate that the start and end of a
block-device map to the same 'pagemap' instance.
Teach the dax-core and device-mapper to validate the 'pagemap' on a
per-target basis. This is accomplished by refactoring the
bdev_dax_supported() internals into generic_fsdax_supported() which
takes a sector range to validate. Consequently generic_fsdax_supported()
is suitable to be used in a device-mapper ->iterate_devices() callback.
A new ->dax_supported() operation is added to allow composite devices to
split and route upper-level bdev_dax_supported() requests.
Fixes: ad428cdb52 ("dax: Check the end of the block-device...")
Cc: <stable@vger.kernel.org>
Cc: Ira Weiny <ira.weiny@intel.com>
Cc: Dave Jiang <dave.jiang@intel.com>
Cc: Keith Busch <keith.busch@intel.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Vishal Verma <vishal.l.verma@intel.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Reported-by: Pankaj Gupta <pagupta@redhat.com>
Reviewed-by: Pankaj Gupta <pagupta@redhat.com>
Tested-by: Pankaj Gupta <pagupta@redhat.com>
Tested-by: Vaibhav Jain <vaibhav@linux.ibm.com>
Reviewed-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
md->dax_dev defaults to NULL and there is no need to initialize it
if CONFIG_DAX_DRIVER is disabled.
Signed-off-by: Peng Wang <rocking@whu.edu.cn>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Storage devices which report supporting discard commands like
WRITE_SAME_16 with unmap, but reject discard commands sent to the
storage device. This is a clear storage firmware bug but it doesn't
change the fact that should a program cause discards to be sent to a
multipath device layered on this buggy storage, all paths can end up
failed at the same time from the discards, causing possible I/O loss.
The first discard to a path will fail with Illegal Request, Invalid
field in cdb, e.g.:
kernel: sd 8:0:8:19: [sdfn] tag#0 FAILED Result: hostbyte=DID_OK driverbyte=DRIVER_SENSE
kernel: sd 8:0:8:19: [sdfn] tag#0 Sense Key : Illegal Request [current]
kernel: sd 8:0:8:19: [sdfn] tag#0 Add. Sense: Invalid field in cdb
kernel: sd 8:0:8:19: [sdfn] tag#0 CDB: Write same(16) 93 08 00 00 00 00 00 a0 08 00 00 00 80 00 00 00
kernel: blk_update_request: critical target error, dev sdfn, sector 10487808
The SCSI layer converts this to the BLK_STS_TARGET error number, the sd
device disables its support for discard on this path, and because of the
BLK_STS_TARGET error multipath fails the discard without failing any
path or retrying down a different path. But subsequent discards can
cause path failures. Any discards sent to the path which already failed
a discard ends up failing with EIO from blk_cloned_rq_check_limits with
an "over max size limit" error since the discard limit was set to 0 by
the sd driver for the path. As the error is EIO, this now fails the
path and multipath tries to send the discard down the next path. This
cycle continues as discards are sent until all paths fail.
Fix this by training DM core to disable DISCARD if the underlying
storage already did so.
Also, fix branching in dm_done() and clone_endio() to reflect the
mutually exclussive nature of the IO operations in question.
Cc: stable@vger.kernel.org
Reported-by: David Jeffery <djeffery@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
The limit was already incorporated to dm-crypt with commit 4e870e948f
("dm crypt: fix error with too large bios"), so we don't need to apply
it globally to all targets. The quantity BIO_MAX_PAGES * PAGE_SIZE is
wrong anyway because the variable ti->max_io_len it is supposed to be in
the units of 512-byte sectors not in bytes.
Reduction of the limit to 1048576 sectors could even cause data
corruption in rare cases - suppose that we have a dm-striped device with
stripe size 768MiB. The target will call dm_set_target_max_io_len with
the value 1572864. The buggy code would reduce it to 1048576. Now, the
dm-core will errorneously split the bios on 1048576-sector boundary
insetad of 1572864-sector boundary and pass these stripe-crossing bios
to the striped target.
Cc: stable@vger.kernel.org # v4.16+
Fixes: 8f50e35815 ("dm: limit the max bio size as BIO_MAX_PAGES * PAGE_SIZE")
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Acked-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Do not just call blk_queue_split() if the bio is_abnormal_io().
Fixes: 568c73a355 ("dm: update dm_process_bio() to split bio if in ->make_request_fn()")
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
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>
Must call blk_queue_split() otherwise queue_limits for abnormal requests
(e.g. discard, writesame, etc) won't be imposed.
In addition, add dm_queue_split() to simplify DM specific splitting that
is needed for targets that impose ti->max_io_len.
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
bio_trim() has an early return, which makes it _not_ idempotent, if the
offset is 0 and the bio's bi_size already matches the requested size.
Prior to DM, all users of bio_trim() were fine with this. But DM has
exposed the fact that bio_trim()'s early return is incompatible with a
cloned bio whose integrity payload must be trimmed via
bio_integrity_trim().
Fix this by reverting DM back to doing the equivalent of bio_trim() but
in an idempotent manner (so bio_integrity_trim is always performed).
Follow-on work is needed to assess what benefit bio_trim()'s early
return is providing to its existing callers.
Reported-by: Milan Broz <gmazyland@gmail.com>
Fixes: 57c36519e4 ("dm: fix clone_bio() to trigger blk_recount_segments()")
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Block core changes to switch bio-based IO accounting to be percpu had a
side-effect of altering DM core to now rely on calling waitqueue_active
(in both bio-based and request-based) to check if another task is in
dm_wait_for_completion().
A memory barrier is needed before calling waitqueue_active(). DM core
doesn't piggyback on a preceding memory barrier so it must explicitly
use its own.
For more details on why using waitqueue_active() without a preceding
barrier is unsafe, please see the comment before the waitqueue_active()
definition in include/linux/wait.h.
Add the missing memory barrier by switching to using wq_has_sleeper().
Fixes: 6f75723190 ("dm: remove the pending IO accounting")
Fixes: c4576aed8d ("dm: fix request-based dm's use of dm_wait_for_completion")
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
The risk of redundant IO accounting was not taken into consideration
when commit 18a25da843 ("dm: ensure bio submission follows a
depth-first tree walk") introduced IO splitting in terms of recursion
via generic_make_request().
Fix this by subtracting the split bio's payload from the IO stats that
were already accounted for by start_io_acct() upon dm_make_request()
entry. This repeat oscillation of the IO accounting, up then down,
isn't ideal but refactoring DM core's IO splitting to pre-split bios
_before_ they are accounted turned out to be an excessive amount of
change that will need a full development cycle to refine and verify.
Before this fix:
/dev/mapper/stripe_dev is a 4-way stripe using a 32k chunksize, so
bios are split on 32k boundaries.
# fio --name=16M --filename=/dev/mapper/stripe_dev --rw=write --bs=64k --size=16M \
--iodepth=1 --ioengine=libaio --direct=1 --refill_buffers
with debugging added:
[103898.310264] device-mapper: core: start_io_acct: dm-2 WRITE bio->bi_iter.bi_sector=0 len=128
[103898.318704] device-mapper: core: __split_and_process_bio: recursing for following split bio:
[103898.329136] device-mapper: core: start_io_acct: dm-2 WRITE bio->bi_iter.bi_sector=64 len=64
...
16M written yet 136M (278528 * 512b) accounted:
# cat /sys/block/dm-2/stat | awk '{ print $7 }'
278528
After this fix:
16M written and 16M (32768 * 512b) accounted:
# cat /sys/block/dm-2/stat | awk '{ print $7 }'
32768
Fixes: 18a25da843 ("dm: ensure bio submission follows a depth-first tree walk")
Cc: stable@vger.kernel.org # 4.16+
Reported-by: Bryan Gurney <bgurney@redhat.com>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
DM's clone_bio() now benefits from using bio_trim() by fixing the fact
that clone_bio() wasn't clearing BIO_SEG_VALID like bio_trim() does;
which triggers blk_recount_segments() via bio_phys_segments().
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
- Fix DM to allow reads that exceed readahead limits by setting io_pages
in the backing_dev_info.
- A couple code cleanups in request-based DM.
- Fix various DM targets to check for device sector overflow if
CONFIG_LBDAF is not set.
- Use u64 instead of sector_t to store iv_offset in DM crypt; sector_t
isn't large enough on 32bit when CONFIG_LBDAF is not set.
- Performance fixes to DM's kcopyd and the snapshot target focused on
limiting memory use and workqueue stalls.
- Fix typos in the integrity and writecache targets.
- Log which algorithm is used for dm-crypt's encryption and
dm-integrity's hashing.
- Fix false -EBUSY errors in DM raid target's handling of check/repair
messages.
- Fix DM flakey target's corrupt_bio_byte feature to reliably corrupt
the Nth byte in a bio's payload.
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Merge tag 'for-4.21/dm-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm
Pull device mapper updates from Mike Snitzer:
- Eliminate a couple indirect calls from bio-based DM core.
- Fix DM to allow reads that exceed readahead limits by setting
io_pages in the backing_dev_info.
- A couple code cleanups in request-based DM.
- Fix various DM targets to check for device sector overflow if
CONFIG_LBDAF is not set.
- Use u64 instead of sector_t to store iv_offset in DM crypt; sector_t
isn't large enough on 32bit when CONFIG_LBDAF is not set.
- Performance fixes to DM's kcopyd and the snapshot target focused on
limiting memory use and workqueue stalls.
- Fix typos in the integrity and writecache targets.
- Log which algorithm is used for dm-crypt's encryption and
dm-integrity's hashing.
- Fix false -EBUSY errors in DM raid target's handling of check/repair
messages.
- Fix DM flakey target's corrupt_bio_byte feature to reliably corrupt
the Nth byte in a bio's payload.
* tag 'for-4.21/dm-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm:
dm: do not allow readahead to limit IO size
dm raid: fix false -EBUSY when handling check/repair message
dm rq: cleanup leftover code from recently removed q->mq_ops branching
dm verity: log the hash algorithm implementation
dm crypt: log the encryption algorithm implementation
dm integrity: fix spelling mistake in workqueue name
dm flakey: Properly corrupt multi-page bios.
dm: Check for device sector overflow if CONFIG_LBDAF is not set
dm crypt: use u64 instead of sector_t to store iv_offset
dm kcopyd: Fix bug causing workqueue stalls
dm snapshot: Fix excessive memory usage and workqueue stalls
dm bufio: update comment in dm-bufio.c
dm writecache: fix typo in error msg for creating writecache_flush_thread
dm: remove indirect calls from __send_changing_extent_only()
dm mpath: only flush workqueue when needed
dm rq: remove unused arguments from rq_completed()
dm: avoid indirect call in __dm_make_request
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Merge tag 'for-4.21/block-20181221' of git://git.kernel.dk/linux-block
Pull block updates from Jens Axboe:
"This is the main pull request for block/storage for 4.21.
Larger than usual, it was a busy round with lots of goodies queued up.
Most notable is the removal of the old IO stack, which has been a long
time coming. No new features for a while, everything coming in this
week has all been fixes for things that were previously merged.
This contains:
- Use atomic counters instead of semaphores for mtip32xx (Arnd)
- Cleanup of the mtip32xx request setup (Christoph)
- Fix for circular locking dependency in loop (Jan, Tetsuo)
- bcache (Coly, Guoju, Shenghui)
* Optimizations for writeback caching
* Various fixes and improvements
- nvme (Chaitanya, Christoph, Sagi, Jay, me, Keith)
* host and target support for NVMe over TCP
* Error log page support
* Support for separate read/write/poll queues
* Much improved polling
* discard OOM fallback
* Tracepoint improvements
- lightnvm (Hans, Hua, Igor, Matias, Javier)
* Igor added packed metadata to pblk. Now drives without metadata
per LBA can be used as well.
* Fix from Geert on uninitialized value on chunk metadata reads.
* Fixes from Hans and Javier to pblk recovery and write path.
* Fix from Hua Su to fix a race condition in the pblk recovery
code.
* Scan optimization added to pblk recovery from Zhoujie.
* Small geometry cleanup from me.
- Conversion of the last few drivers that used the legacy path to
blk-mq (me)
- Removal of legacy IO path in SCSI (me, Christoph)
- Removal of legacy IO stack and schedulers (me)
- Support for much better polling, now without interrupts at all.
blk-mq adds support for multiple queue maps, which enables us to
have a map per type. This in turn enables nvme to have separate
completion queues for polling, which can then be interrupt-less.
Also means we're ready for async polled IO, which is hopefully
coming in the next release.
- Killing of (now) unused block exports (Christoph)
- Unification of the blk-rq-qos and blk-wbt wait handling (Josef)
- Support for zoned testing with null_blk (Masato)
- sx8 conversion to per-host tag sets (Christoph)
- IO priority improvements (Damien)
- mq-deadline zoned fix (Damien)
- Ref count blkcg series (Dennis)
- Lots of blk-mq improvements and speedups (me)
- sbitmap scalability improvements (me)
- Make core inflight IO accounting per-cpu (Mikulas)
- Export timeout setting in sysfs (Weiping)
- Cleanup the direct issue path (Jianchao)
- Export blk-wbt internals in block debugfs for easier debugging
(Ming)
- Lots of other fixes and improvements"
* tag 'for-4.21/block-20181221' of git://git.kernel.dk/linux-block: (364 commits)
kyber: use sbitmap add_wait_queue/list_del wait helpers
sbitmap: add helpers for add/del wait queue handling
block: save irq state in blkg_lookup_create()
dm: don't reuse bio for flushes
nvme-pci: trace SQ status on completions
nvme-rdma: implement polling queue map
nvme-fabrics: allow user to pass in nr_poll_queues
nvme-fabrics: allow nvmf_connect_io_queue to poll
nvme-core: optionally poll sync commands
block: make request_to_qc_t public
nvme-tcp: fix spelling mistake "attepmpt" -> "attempt"
nvme-tcp: fix endianess annotations
nvmet-tcp: fix endianess annotations
nvme-pci: refactor nvme_poll_irqdisable to make sparse happy
nvme-pci: only set nr_maps to 2 if poll queues are supported
nvmet: use a macro for default error location
nvmet: fix comparison of a u16 with -1
blk-mq: enable IO poll if .nr_queues of type poll > 0
blk-mq: change blk_mq_queue_busy() to blk_mq_queue_inflight()
blk-mq: skip zero-queue maps in blk_mq_map_swqueue
...
DM currently has a statically allocated bio that it uses to issue empty
flushes. It doesn't submit this bio, it just uses it for maintaining
state while setting up clones. Multiple users can access this bio at the
same time. This wasn't previously an issue, even if it was a bit iffy,
but with the blkg associations it can become one.
We setup the blkg association, then clone bio's and submit, then remove
the blkg assocation again. But since we can have multiple tasks doing
this at the same time, against multiple blkg's, then we can either lose
references to a blkg, or put it twice. The latter causes complaints on
the percpu ref being <= 0 when released, and can cause use-after-free as
well. Ming reports that xfstest generic/475 triggers this:
------------[ cut here ]------------
percpu ref (blkg_release) <= 0 (0) after switching to atomic
WARNING: CPU: 13 PID: 0 at lib/percpu-refcount.c:155 percpu_ref_switch_to_atomic_rcu+0x2c9/0x4a0
Switch to just using an on-stack bio for this, and get rid of the
embedded bio.
Fixes: 5cdf2e3fea ("blkcg: associate blkg when associating a device")
Reported-by: Ming Lei <ming.lei@redhat.com>
Tested-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Indirect calls are inefficient because of retpolines that are used for
spectre workaround. This patch replaces an indirect call with a condition
(that can be predicted by the branch predictor).
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
There's a single user of this function, dm, and dm just wants
to check if IO is inflight, not that it's just allocated.
This fixes a hang with srp/002 in blktests with dm, where it tries
to suspend but waits for inflight IO to finish first. As it checks
for just allocated requests, this fails.
Tested-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
The md->wait waitqueue is used by both bio-based and request-based DM.
Commit dbd3bbd291 ("dm rq: leverage blk_mq_queue_busy() to check for
outstanding IO") lost sight of the requirement that
dm_wait_for_completion() must work with all types of DM devices.
Fix md_in_flight() to call the blk-mq or bio-based method accordingly.
Fixes: dbd3bbd291 ("dm rq: leverage blk_mq_queue_busy() to check for outstanding IO")
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
After switching to percpu inflight counters, the inflight check
is totally buggy. It's perfectly valid for some counters to be
non-zero while having a total inflight IO count of 0, that's how
these kinds of counters work (inc on one CPU, dec on another).
Fix the md_in_flight() check to sum all counters before returning
a false positive, potentially.
While at it, remove the inflight read for IO completion. We don't
need it, just wake anyone that's waiting for the IO count to drop
to zero. The caller needs to re-check that value anyway when woken,
which it does.
Fixes: 6f75723190 ("dm: remove the pending IO accounting")
Acked-by: Mike Snitzer <snitzer@redhat.com>
Reported-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
generic_start_io_acct and generic_end_io_acct already update the variable
in_flight using atomic operations, so we don't have to overwrite them
again.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
The next patch changes the macro bio_set_dev() to associate a bio with a
blkg based on the device set. However, dm creates a static bio to be
used as the basis for cloning empty flush bios on creation. The
bio_set_dev() call in alloc_dev() will cause problems with the next
patch adding association to bio_set_dev() because the call is before the
bdev is associated with a gendisk (bd_disk is %NULL). To get around
this, set the device on the static bio every time and use that to clone
to the other bios.
Signed-off-by: Dennis Zhou <dennis@kernel.org>
Acked-by: Mike Snitzer <snitzer@redhat.com>
Cc: Alasdair Kergon <agk@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Otherwise the incoming bios, of various types, won't be shaped based on
the DM device's advertised limits.
Depends-on: af67c31fba ("blk: remove bio_set arg from blk_queue_split()")
Fixes: 744889b7cb ("block: don't deal with discard limit in blkdev_issue_discard()")
Cc: stable@vger.kernel.org
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
With the legacy request path gone there is no real need to override the
queue_lock.
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
(.request_fn) from request-based DM. Jens has already started
preparing for complete removal of the legacy IO path in 4.21 but this
earlier removal of support from DM has been coordinated with Jens (as
evidenced by the commit being attributed to him). Making
request-based DM exclussively blk-mq only cleans up that portion of DM
core quite nicely.
- Convert the thinp and zoned targets over to using refcount_t where
applicable.
- A couple fixes to the DM zoned target for refcounting and other races
buried in the implementation of metadata block creation and use.
- Small cleanups to remove redundant unlikely() around a couple
WARN_ON_ONCE().
- Simplify how dm-ioctl copies from userspace, eliminating some
potential for a malicious user trying to change the executed ioctl
after its processing has begun.
- Tweaked DM crypt target to use the DM device name when naming the
various workqueues created for a particular DM crypt device (makes the
N workqueues for a DM crypt device more easily understood and enhances
user's accounting capabilities at a glance via "ps")
- Small fixup to remove dead branch in DM writecache's memory_entry().
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Merge tag 'for-4.20/dm-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm
Pull device mapper updates from Mike Snitzer:
- The biggest change this cycle is to remove support for the legacy IO
path (.request_fn) from request-based DM.
Jens has already started preparing for complete removal of the legacy
IO path in 4.21 but this earlier removal of support from DM has been
coordinated with Jens (as evidenced by the commit being attributed to
him).
Making request-based DM exclussively blk-mq only cleans up that
portion of DM core quite nicely.
- Convert the thinp and zoned targets over to using refcount_t where
applicable.
- A couple fixes to the DM zoned target for refcounting and other races
buried in the implementation of metadata block creation and use.
- Small cleanups to remove redundant unlikely() around a couple
WARN_ON_ONCE().
- Simplify how dm-ioctl copies from userspace, eliminating some
potential for a malicious user trying to change the executed ioctl
after its processing has begun.
- Tweaked DM crypt target to use the DM device name when naming the
various workqueues created for a particular DM crypt device (makes
the N workqueues for a DM crypt device more easily understood and
enhances user's accounting capabilities at a glance via "ps")
- Small fixup to remove dead branch in DM writecache's memory_entry().
* tag 'for-4.20/dm-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm:
dm writecache: remove disabled code in memory_entry()
dm zoned: fix various dmz_get_mblock() issues
dm zoned: fix metadata block ref counting
dm raid: avoid bitmap with raid4/5/6 journal device
dm crypt: make workqueue names device-specific
dm: add dm_table_device_name()
dm ioctl: harden copy_params()'s copy_from_user() from malicious users
dm: remove unnecessary unlikely() around WARN_ON_ONCE()
dm zoned: target: use refcount_t for dm zoned reference counters
dm thin: use refcount_t for thin_c reference counting
dm table: require that request-based DM be layered on blk-mq devices
dm: rename DM_TYPE_MQ_REQUEST_BASED to DM_TYPE_REQUEST_BASED
dm: remove legacy request-based IO path
Dispatching a report zones command through the request queue is a major
pain due to the command reply payload rewriting necessary. Given that
blkdev_report_zones() is executing everything synchronously, implement
report zones as a block device file operation instead, allowing major
simplification of the code in many places.
sd, null-blk, dm-linear and dm-flakey being the only block device
drivers supporting exposing zoned block devices, these drivers are
modified to provide the device side implementation of the
report_zones() block device file operation.
For device mappers, a new report_zones() target type operation is
defined so that the upper block layer calls blkdev_report_zones() can
be propagated down to the underlying devices of the dm targets.
Implementation for this new operation is added to the dm-linear and
dm-flakey targets.
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
[Damien]
* Changed method block_device argument to gendisk
* Various bug fixes and improvements
* Added support for null_blk, dm-linear and dm-flakey.
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
WARN_ON() already contains an unlikely(), so it's not necessary to
wrap it into another.
Signed-off-by: Igor Stoppa <igor.stoppa@huawei.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Now that request-based DM is only using blk-mq, there is no need to
differentiate between legacy "rq" and new "mq". We're back to a single
request-based DM -- and there was much rejoicing!
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
dm supports both, and since we're killing off the legacy path in
general, get rid of it in dm.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
If dm-linear or dm-flakey are layered on top of a partition of a zoned
block device, remapping of the start sector and write pointer position
of the zones reported by a report zones BIO must be modified to account
for the target table entry mapping (start offset within the device and
entry mapping with the dm device). If the target's backing device is a
partition of a whole disk, the start sector on the physical device of
the partition must also be accounted for when modifying the zone
information. However, dm_remap_zone_report() was not considering this
last case, resulting in incorrect zone information remapping with
targets using disk partitions.
Fix this by calculating the target backing device start sector using
the position of the completed report zones BIO and the unchanged
position and size of the original report zone BIO. With this value
calculated, the start sector and write pointer position of the target
zones can be correctly remapped.
Fixes: 10999307c1 ("dm: introduce dm_remap_zone_report()")
Cc: stable@vger.kernel.org
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Add and use a new op_stat_group() function for indexing partition stat
fields rather than indexing them by rq_data_dir() or bio_data_dir().
This function works similarly to op_is_sync() in that it takes the
request::cmd_flags or bio::bi_opf flags and determines which stats
should et updated.
In addition, the second parameter to generic_start_io_acct() and
generic_end_io_acct() is now a REQ_OP rather than simply a read or
write bit and it uses op_stat_group() on the parameter to determine
the stat group.
Note that the partition in_flight counts are not part of the per-cpu
statistics and as such are not indexed via this function. It's now
indexed by op_is_write().
tj: Refreshed on top of v4.17. Updated to pass around REQ_OP.
Signed-off-by: Michael Callahan <michaelcallahan@fb.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Joshua Morris <josh.h.morris@us.ibm.com>
Cc: Philipp Reisner <philipp.reisner@linbit.com>
Cc: Matias Bjorling <mb@lightnvm.io>
Cc: Kent Overstreet <kent.overstreet@gmail.com>
Cc: Alasdair Kergon <agk@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Currently device_supports_dax() just checks to see if the QUEUE_FLAG_DAX
flag is set on the device's request queue to decide whether or not the
device supports filesystem DAX. Really we should be using
bdev_dax_supported() like filesystems do at mount time. This performs
other tests like checking to make sure the dax_direct_access() path works.
We also explicitly clear QUEUE_FLAG_DAX on the DM device's request queue if
any of the underlying devices do not support DAX. This makes the handling
of QUEUE_FLAG_DAX consistent with the setting/clearing of most other flags
in dm_table_set_restrictions().
Now that bdev_dax_supported() explicitly checks for QUEUE_FLAG_DAX, this
will ensure that filesystems built upon DM devices will only be able to
mount with DAX if all underlying devices also support DAX.
Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Fixes: commit 545ed20e6d ("dm: add infrastructure for DAX support")
Cc: stable@vger.kernel.org
Acked-by: Dan Williams <dan.j.williams@intel.com>
Reviewed-by: Toshi Kani <toshi.kani@hpe.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Use of bio_clone_bioset() is inefficient if there is no need to clone
the original bio's bio_vec array. Best to use the bio_clone_fast()
variant. Also, just using bio_advance() is only part of what is needed
to properly setup the clone -- it doesn't account for the various
bio_integrity() related work that also needs to be performed (see
bio_split).
Address both of these issues by switching from bio_clone_bioset() to
bio_split().
Fixes: 18a25da8 ("dm: ensure bio submission follows a depth-first tree walk")
Cc: stable@vger.kernel.org # 4.15+, requires removal of '&' before md->queue->bio_split
Reported-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: NeilBrown <neilb@suse.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
* DAX broke a fundamental assumption of truncate of file mapped pages.
The truncate path assumed that it is safe to disconnect a pinned page
from a file and let the filesystem reclaim the physical block. With DAX
the page is equivalent to the filesystem block. Introduce
dax_layout_busy_page() to enable filesystems to wait for pinned DAX
pages to be released. Without this wait a filesystem could allocate
blocks under active device-DMA to a new file.
* DAX arranges for the block layer to be bypassed and uses
dax_direct_access() + copy_to_iter() to satisfy read(2) calls.
However, the memcpy_mcsafe() facility is available through the pmem
block driver. In order to safely handle media errors, via the DAX
block-layer bypass, introduce copy_to_iter_mcsafe().
* Fix cache management policy relative to the ACPI NFIT Platform
Capabilities Structure to properly elide cache flushes when they are not
necessary. The table indicates whether CPU caches are power-fail
protected. Clarify that a deep flush is always performed on
REQ_{FUA,PREFLUSH} requests.
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Merge tag 'libnvdimm-for-4.18' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm
Pull libnvdimm updates from Dan Williams:
"This adds a user for the new 'bytes-remaining' updates to
memcpy_mcsafe() that you already received through Ingo via the
x86-dax- for-linus pull.
Not included here, but still targeting this cycle, is support for
handling memory media errors (poison) consumed via userspace dax
mappings.
Summary:
- DAX broke a fundamental assumption of truncate of file mapped
pages. The truncate path assumed that it is safe to disconnect a
pinned page from a file and let the filesystem reclaim the physical
block. With DAX the page is equivalent to the filesystem block.
Introduce dax_layout_busy_page() to enable filesystems to wait for
pinned DAX pages to be released. Without this wait a filesystem
could allocate blocks under active device-DMA to a new file.
- DAX arranges for the block layer to be bypassed and uses
dax_direct_access() + copy_to_iter() to satisfy read(2) calls.
However, the memcpy_mcsafe() facility is available through the pmem
block driver. In order to safely handle media errors, via the DAX
block-layer bypass, introduce copy_to_iter_mcsafe().
- Fix cache management policy relative to the ACPI NFIT Platform
Capabilities Structure to properly elide cache flushes when they
are not necessary. The table indicates whether CPU caches are
power-fail protected. Clarify that a deep flush is always performed
on REQ_{FUA,PREFLUSH} requests"
* tag 'libnvdimm-for-4.18' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm: (21 commits)
dax: Use dax_write_cache* helpers
libnvdimm, pmem: Do not flush power-fail protected CPU caches
libnvdimm, pmem: Unconditionally deep flush on *sync
libnvdimm, pmem: Complete REQ_FLUSH => REQ_PREFLUSH
acpi, nfit: Remove ecc_unit_size
dax: dax_insert_mapping_entry always succeeds
libnvdimm, e820: Register all pmem resources
libnvdimm: Debug probe times
linvdimm, pmem: Preserve read-only setting for pmem devices
x86, nfit_test: Add unit test for memcpy_mcsafe()
pmem: Switch to copy_to_iter_mcsafe()
dax: Report bytes remaining in dax_iomap_actor()
dax: Introduce a ->copy_to_iter dax operation
uio, lib: Fix CONFIG_ARCH_HAS_UACCESS_MCSAFE compilation
xfs, dax: introduce xfs_break_dax_layouts()
xfs: prepare xfs_break_layouts() for another layout type
xfs: prepare xfs_break_layouts() to be called with XFS_MMAPLOCK_EXCL
mm, fs, dax: handle layout changes to pinned dax mappings
mm: fix __gup_device_huge vs unmap
mm: introduce MEMORY_DEVICE_FS_DAX and CONFIG_DEV_PAGEMAP_OPS
...
We can't just copy and clear a bio_set, use the bio helper to
setup a new bio_set with the settings from another one.
Fixes: 6f1c819c21 ("dm: convert to bioset_init()/mempool_init()")
Reported-by: Venkat R.B <vrbagal1@linux.vnet.ibm.com>
Tested-by: Venkat R.B <vrbagal1@linux.vnet.ibm.com>
Tested-by: Li Wang <liwang@redhat.com>
Reviewed-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Merge tag 'for-4.18/block-20180603' of git://git.kernel.dk/linux-block
Pull block updates from Jens Axboe:
- clean up how we pass around gfp_t and
blk_mq_req_flags_t (Christoph)
- prepare us to defer scheduler attach (Christoph)
- clean up drivers handling of bounce buffers (Christoph)
- fix timeout handling corner cases (Christoph/Bart/Keith)
- bcache fixes (Coly)
- prep work for bcachefs and some block layer optimizations (Kent).
- convert users of bio_sets to using embedded structs (Kent).
- fixes for the BFQ io scheduler (Paolo/Davide/Filippo)
- lightnvm fixes and improvements (Matias, with contributions from Hans
and Javier)
- adding discard throttling to blk-wbt (me)
- sbitmap blk-mq-tag handling (me/Omar/Ming).
- remove the sparc jsflash block driver, acked by DaveM.
- Kyber scheduler improvement from Jianchao, making it more friendly
wrt merging.
- conversion of symbolic proc permissions to octal, from Joe Perches.
Previously the block parts were a mix of both.
- nbd fixes (Josef and Kevin Vigor)
- unify how we handle the various kinds of timestamps that the block
core and utility code uses (Omar)
- three NVMe pull requests from Keith and Christoph, bringing AEN to
feature completeness, file backed namespaces, cq/sq lock split, and
various fixes
- various little fixes and improvements all over the map
* tag 'for-4.18/block-20180603' of git://git.kernel.dk/linux-block: (196 commits)
blk-mq: update nr_requests when switching to 'none' scheduler
block: don't use blocking queue entered for recursive bio submits
dm-crypt: fix warning in shutdown path
lightnvm: pblk: take bitmap alloc. out of critical section
lightnvm: pblk: kick writer on new flush points
lightnvm: pblk: only try to recover lines with written smeta
lightnvm: pblk: remove unnecessary bio_get/put
lightnvm: pblk: add possibility to set write buffer size manually
lightnvm: fix partial read error path
lightnvm: proper error handling for pblk_bio_add_pages
lightnvm: pblk: fix smeta write error path
lightnvm: pblk: garbage collect lines with failed writes
lightnvm: pblk: rework write error recovery path
lightnvm: pblk: remove dead function
lightnvm: pass flag on graceful teardown to targets
lightnvm: pblk: check for chunk size before allocating it
lightnvm: pblk: remove unnecessary argument
lightnvm: pblk: remove unnecessary indirection
lightnvm: pblk: return NVM_ error on failed submission
lightnvm: pblk: warn in case of corrupted write buffer
...
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>
Convert the core block functionality to embedded bio sets.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Similar to the ->copy_from_iter() operation, a platform may want to
deploy an architecture or device specific routine for handling reads
from a dax_device like /dev/pmemX. On x86 this routine will point to a
machine check safe version of copy_to_iter(). For now, add the plumbing
to device-mapper and the dax core.
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Mike Snitzer <snitzer@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
* A rework of the filesytem-dax implementation provides for detection of
unmap operations (truncate / hole punch) colliding with in-progress
device-DMA. A fix for these collisions remains a work-in-progress
pending resolution of truncate latency and starvation regressions.
* The of_pmem driver expands the users of libnvdimm outside of x86 and
ACPI to describe an implementation of persistent memory on PowerPC with
Open Firmware / Device tree.
* Address Range Scrub (ARS) handling is completely rewritten to account for
the fact that ARS may run for 100s of seconds and there is no platform
defined way to cancel it. ARS will now no longer block namespace
initialization.
* The NVDIMM Namespace Label implementation is updated to handle label
areas as small as 1K, down from 128K.
* Miscellaneous cleanups and updates to unit test infrastructure.
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Merge tag 'libnvdimm-for-4.17' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm
Pull libnvdimm updates from Dan Williams:
"This cycle was was not something I ever want to repeat as there were
several late changes that have only now just settled.
Half of the branch up to commit d2c997c0f1 ("fs, dax: use
page->mapping to warn...") have been in -next for several releases.
The of_pmem driver and the address range scrub rework were late
arrivals, and the dax work was scaled back at the last moment.
The of_pmem driver missed a previous merge window due to an oversight.
A sense of obligation to rectify that miss is why it is included for
4.17. It has acks from PowerPC folks. Stephen reported a build failure
that only occurs when merging it with your latest tree, for now I have
fixed that up by disabling modular builds of of_pmem. A test merge
with your tree has received a build success report from the 0day robot
over 156 configs.
An initial version of the ARS rework was submitted before the merge
window. It is self contained to libnvdimm, a net code reduction, and
passing all unit tests.
The filesystem-dax changes are based on the wait_var_event()
functionality from tip/sched/core. However, late review feedback
showed that those changes regressed truncate performance to a large
degree. The branch was rewound to drop the truncate behavior change
and now only includes preparation patches and cleanups (with full acks
and reviews). The finalization of this dax-dma-vs-trnucate work will
need to wait for 4.18.
Summary:
- A rework of the filesytem-dax implementation provides for detection
of unmap operations (truncate / hole punch) colliding with
in-progress device-DMA. A fix for these collisions remains a
work-in-progress pending resolution of truncate latency and
starvation regressions.
- The of_pmem driver expands the users of libnvdimm outside of x86
and ACPI to describe an implementation of persistent memory on
PowerPC with Open Firmware / Device tree.
- Address Range Scrub (ARS) handling is completely rewritten to
account for the fact that ARS may run for 100s of seconds and there
is no platform defined way to cancel it. ARS will now no longer
block namespace initialization.
- The NVDIMM Namespace Label implementation is updated to handle
label areas as small as 1K, down from 128K.
- Miscellaneous cleanups and updates to unit test infrastructure"
* tag 'libnvdimm-for-4.17' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm: (39 commits)
libnvdimm, of_pmem: workaround OF_NUMA=n build error
nfit, address-range-scrub: add module option to skip initial ars
nfit, address-range-scrub: rework and simplify ARS state machine
nfit, address-range-scrub: determine one platform max_ars value
powerpc/powernv: Create platform devs for nvdimm buses
doc/devicetree: Persistent memory region bindings
libnvdimm: Add device-tree based driver
libnvdimm: Add of_node to region and bus descriptors
libnvdimm, region: quiet region probe
libnvdimm, namespace: use a safe lookup for dimm device name
libnvdimm, dimm: fix dpa reservation vs uninitialized label area
libnvdimm, testing: update the default smart ctrl_temperature
libnvdimm, testing: Add emulation for smart injection commands
nfit, address-range-scrub: introduce nfit_spa->ars_state
libnvdimm: add an api to cast a 'struct nd_region' to its 'struct device'
nfit, address-range-scrub: fix scrub in-progress reporting
dax, dm: allow device-mapper to operate without dax support
dax: introduce CONFIG_DAX_DRIVER
fs, dax: use page->mapping to warn if truncate collides with a busy page
ext2, dax: introduce ext2_dax_aops
...
that table's block devices, while issuing the ioctl to one of those
block devices.
- DM core passthrough ioctl fix to _not_ override the fmode_t used to
issue the ioctl. Overriding by using the fmode_t that the block
device was originally open with during DM table load is a liability.
- Add DM core support for secure erase forwarding and update the DM
linear and DM striped targets to support them.
- A DM core 4.16 stable fix to allow abnormal IO (e.g. discard, write
same, write zeroes) for targets that make use of the non-splitting IO
variant (as is done for multipath or thinp when layered directly on
NVMe).
- Allow DM targets to return a payload in response to a DM message that
they are sent. This is useful for DM targets that would like to
provide statistics data in response to DM messages.
- Update DM bufio to support non-power-of-2 block sizes. Numerous other
related changes prepare the DM bufio code for this support.
- Fix DM crypt to use a bounded amount of memory across the entire
system. This is to avoid OOM that can otherwise occur in response to
certain pathological IO workloads (e.g. discarding a large DM crypt
device).
- Add a 'check_at_most_once' feature to the DM verity target to allow
verity to be used on mobile devices that have very limited resources.
- Fix the DM integrity target to fail early if a keyed algorithm
(e.g. HMAC) is to be used but the key isn't set.
- Add non-power-of-2 support to the DM unstripe target.
- Eliminate the use of a Variable Length Array in the DM stripe target.
- Update the DM log-writes target to record metadata (REQ_META flag).
- DM raid fixes for its nosync status and some variable range issues.
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Merge tag 'for-4.17/dm-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm
Pull device mapper updates from Mike Snitzer:
- DM core passthrough ioctl fix to retain reference to DM table, and
that table's block devices, while issuing the ioctl to one of those
block devices.
- DM core passthrough ioctl fix to _not_ override the fmode_t used to
issue the ioctl. Overriding by using the fmode_t that the block
device was originally open with during DM table load is a liability.
- Add DM core support for secure erase forwarding and update the DM
linear and DM striped targets to support them.
- A DM core 4.16 stable fix to allow abnormal IO (e.g. discard, write
same, write zeroes) for targets that make use of the non-splitting IO
variant (as is done for multipath or thinp when layered directly on
NVMe).
- Allow DM targets to return a payload in response to a DM message that
they are sent. This is useful for DM targets that would like to
provide statistics data in response to DM messages.
- Update DM bufio to support non-power-of-2 block sizes. Numerous other
related changes prepare the DM bufio code for this support.
- Fix DM crypt to use a bounded amount of memory across the entire
system. This is to avoid OOM that can otherwise occur in response to
certain pathological IO workloads (e.g. discarding a large DM crypt
device).
- Add a 'check_at_most_once' feature to the DM verity target to allow
verity to be used on mobile devices that have very limited resources.
- Fix the DM integrity target to fail early if a keyed algorithm (e.g.
HMAC) is to be used but the key isn't set.
- Add non-power-of-2 support to the DM unstripe target.
- Eliminate the use of a Variable Length Array in the DM stripe target.
- Update the DM log-writes target to record metadata (REQ_META flag).
- DM raid fixes for its nosync status and some variable range issues.
* tag 'for-4.17/dm-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm: (28 commits)
dm: remove fmode_t argument from .prepare_ioctl hook
dm: hold DM table for duration of ioctl rather than use blkdev_get
dm raid: fix parse_raid_params() variable range issue
dm verity: make verity_for_io_block static
dm verity: add 'check_at_most_once' option to only validate hashes once
dm bufio: don't embed a bio in the dm_buffer structure
dm bufio: support non-power-of-two block sizes
dm bufio: use slab cache for dm_buffer structure allocations
dm bufio: reorder fields in dm_buffer structure
dm bufio: relax alignment constraint on slab cache
dm bufio: remove code that merges slab caches
dm bufio: get rid of slab cache name allocations
dm bufio: move dm-bufio.h to include/linux/
dm bufio: delete outdated comment
dm: add support for secure erase forwarding
dm: backfill abnormal IO support to non-splitting IO submission
dm raid: fix nosync status
dm mpath: use DM_MAPIO_SUBMITTED instead of magic number 0 in process_queued_bios()
dm stripe: get rid of a Variable Length Array (VLA)
dm log writes: record metadata flag for better flags record
...
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Merge tag 'for-4.17/block-20180402' of git://git.kernel.dk/linux-block
Pull block layer updates from Jens Axboe:
"It's a pretty quiet round this time, which is nice. This contains:
- series from Bart, cleaning up the way we set/test/clear atomic
queue flags.
- series from Bart, fixing races between gendisk and queue
registration and removal.
- set of bcache fixes and improvements from various folks, by way of
Michael Lyle.
- set of lightnvm updates from Matias, most of it being the 1.2 to
2.0 transition.
- removal of unused DIO flags from Nikolay.
- blk-mq/sbitmap memory ordering fixes from Omar.
- divide-by-zero fix for BFQ from Paolo.
- minor documentation patches from Randy.
- timeout fix from Tejun.
- Alpha "can't write a char atomically" fix from Mikulas.
- set of NVMe fixes by way of Keith.
- bsg and bsg-lib improvements from Christoph.
- a few sed-opal fixes from Jonas.
- cdrom check-disk-change deadlock fix from Maurizio.
- various little fixes, comment fixes, etc from various folks"
* tag 'for-4.17/block-20180402' of git://git.kernel.dk/linux-block: (139 commits)
blk-mq: Directly schedule q->timeout_work when aborting a request
blktrace: fix comment in blktrace_api.h
lightnvm: remove function name in strings
lightnvm: pblk: remove some unnecessary NULL checks
lightnvm: pblk: don't recover unwritten lines
lightnvm: pblk: implement 2.0 support
lightnvm: pblk: implement get log report chunk
lightnvm: pblk: rename ppaf* to addrf*
lightnvm: pblk: check for supported version
lightnvm: implement get log report chunk helpers
lightnvm: make address conversions depend on generic device
lightnvm: add support for 2.0 address format
lightnvm: normalize geometry nomenclature
lightnvm: complete geo structure with maxoc*
lightnvm: add shorten OCSSD version in geo
lightnvm: add minor version to generic geometry
lightnvm: simplify geometry structure
lightnvm: pblk: refactor init/exit sequences
lightnvm: Avoid validation of default op value
lightnvm: centralize permission check for lightnvm ioctl
...
Use the fmode_t that is passed to dm_blk_ioctl() rather than
inconsistently (varies across targets) drop it on the floor by
overriding it with the fmode_t stored in 'struct dm_dev'.
All the persistent reservation functions weren't using the fmode_t they
got back from .prepare_ioctl so remove them.
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Commit 519049afea ("dm: use blkdev_get rather than bdgrab when issuing
pass-through ioctl") inadvertantly introduced a regression relative to
users of device cgroups that issue ioctls (e.g. libvirt). Using
blkdev_get() in DM's passthrough ioctl support implicitly introduced a
cgroup permissions check that would fail unless care were taken to add
all devices in the IO stack to the device cgroup. E.g. rather than just
adding the top-level DM multipath device to the cgroup all the
underlying devices would need to be allowed.
Fix this, to no longer require allowing all underlying devices, by
simply holding the live DM table (which includes the table's original
blkdev_get() reference on the blockdevice that the ioctl will be issued
to) for the duration of the ioctl.
Also, bump the DM ioctl version so a user can know that their device
cgroup allow workaround is no longer needed.
Reported-by: Michal Privoznik <mprivozn@redhat.com>
Suggested-by: Mikulas Patocka <mpatocka@redhat.com>
Fixes: 519049afea ("dm: use blkdev_get rather than bdgrab when issuing pass-through ioctl")
Cc: stable@vger.kernel.org # 4.16
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Set QUEUE_FLAG_SECERASE in DM device's queue_flags if a DM table's
data devices support secure erase.
Also, add support for secure erase to both the linear and striped
targets.
Signed-off-by: Denis Semakin <d.semakin@omprussia.ru>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Otherwise, these abnormal IOs would be sent to the DM target
regardless of whether the target advertised support for them.
Factor out __process_abnormal_io() from __split_and_process_non_flush()
so that discards, write same, etc may be conditionally processed.
Fixes: 978e51ba3 ("dm: optimize bio-based NVMe IO submission")
Cc: stable@vger.kernel.org # 4.16
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Change device-mapper's DAX dependency to require the presence of at
least one DAX_DRIVER. This allows device-mapper to be built without
bringing the DAX core along which is especially wasteful when there are
no DAX drivers, like BLK_DEV_PMEM, configured.
Cc: Alasdair Kergon <agk@redhat.com>
Reported-by: Bart Van Assche <Bart.VanAssche@wdc.com>
Reported-by: kbuild test robot <lkp@intel.com>
Reported-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
dm_get_bdev_for_ioctl()'s return of 0 or 1 must be the result from
prepare_ioctl (1 means the ioctl was issued to a partition, 0 means it
wasn't). Unfortunately commit 519049afea ("dm: use blkdev_get rather
than bdgrab when issuing pass-through ioctl") reused the variable 'r'
to store the return from blkdev_get() that follows prepare_ioctl()
-- whereby dropping prepare_ioctl()'s result on the floor.
This can lead to an ioctl or persistent reservation being issued to a
partition going unnoticed, which implies the extra permission check for
CAP_SYS_RAWIO is skipped.
Fix this by using a different variable to store blkdev_get()'s return.
Fixes: 519049afea ("dm: use blkdev_get rather than bdgrab when issuing pass-through ioctl")
Reported-by: Alasdair G Kergon <agk@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Otherwise an underlying device's teardown (e.g. SCSI) may race with the
DM ioctl or persistent reservation and result in dereferencing driver
memory that gets freed when the underlying device's final blkdev_put()
occurs.
bdgrab() only increases the refcount for the block_device's inode to
ensure the block_device struct itself will not be freed, but does not
guarantee the block_device will remain associated with the gendisk or
its storage.
Cc: stable@vger.kernel.org # 4.8+
Reported-by: David Jeffery <djeffery@redhat.com>
Suggested-by: David Jeffery <djeffery@redhat.com>
Reviewed-by: Ben Marzinski <bmarzins@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
This patch does not change any functionality.
Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com>
Reviewed-by: Joseph Qi <joseph.qi@linux.alibaba.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Philipp Reisner <philipp.reisner@linbit.com>
Cc: Ulf Hansson <ulf.hansson@linaro.org>
Cc: Kees Cook <keescook@chromium.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
dec_pending() is given an error status (possibly 0) to be recorded
against a bio. It can be called several times on the one 'struct
dm_io', and it is careful to only assign a non-zero error to
io->status. However when it then assigned io->status to bio->bi_status,
it is not careful and could overwrite a genuine error status with 0.
This can happen when chained bios are in use. If a bio is chained
beneath the bio that this dm_io is handling, the child bio might
complete and set bio->bi_status before the dm_io completes.
This has been possible since chained bios were introduced in 3.14, and
has become a lot easier to trigger with commit 18a25da843 ("dm: ensure
bio submission follows a depth-first tree walk") as that commit caused
dm to start using chained bios itself.
A particular failure mode is that if a bio spans an 'error' target and a
working target, the 'error' fragment will complete instantly and set the
->bi_status, and the other fragment will normally complete a little
later, and will clear ->bi_status.
The fix is simply to only assign io_error to bio->bi_status when
io_error is not zero.
Reported-and-tested-by: Milan Broz <gmazyland@gmail.com>
Cc: stable@vger.kernel.org (v3.14+)
Signed-off-by: NeilBrown <neilb@suse.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
walk; this is critical to allow forward progress without the need to
use the bioset's BIOSET_NEED_RESCUER.
- Remove DM core's BIOSET_NEED_RESCUER based dm_offload infrastructure.
- DM core cleanups and improvements to make bio-based DM more efficient
(e.g. reduced memory footprint as well leveraging per-bio-data more).
- Introduce new bio-based mode (DM_TYPE_NVME_BIO_BASED) that leverages
the more direct IO submission path in the block layer; this mode is
used by DM multipath and also optimizes targets like DM thin-pool that
stack directly on NVMe data device.
- DM multipath improvements to factor out legacy SCSI-only
(e.g. scsi_dh) code paths to allow for more optimized support for NVMe
multipath.
- A fix for DM multipath path selectors (service-time and queue-length)
to select paths in a more balanced way; largely academic but doesn't
hurt.
- Numerous DM raid target fixes and improvements.
- Add a new DM "unstriped" target that enables Intel to workaround
firmware limitations in some NVMe drives that are striped internally
(this target also works when stacked above the DM "striped" target).
- Various Documentation fixes and improvements.
- Misc. cleanups and fixes across various DM infrastructure and targets
(e.g. bufio, flakey, log-writes, snapshot).
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Merge tag 'for-4.16/dm-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm
Pull device mapper updates from Mike Snitzer:
- DM core fixes to ensure that bio submission follows a depth-first
tree walk; this is critical to allow forward progress without the
need to use the bioset's BIOSET_NEED_RESCUER.
- Remove DM core's BIOSET_NEED_RESCUER based dm_offload infrastructure.
- DM core cleanups and improvements to make bio-based DM more efficient
(e.g. reduced memory footprint as well leveraging per-bio-data more).
- Introduce new bio-based mode (DM_TYPE_NVME_BIO_BASED) that leverages
the more direct IO submission path in the block layer; this mode is
used by DM multipath and also optimizes targets like DM thin-pool
that stack directly on NVMe data device.
- DM multipath improvements to factor out legacy SCSI-only (e.g.
scsi_dh) code paths to allow for more optimized support for NVMe
multipath.
- A fix for DM multipath path selectors (service-time and queue-length)
to select paths in a more balanced way; largely academic but doesn't
hurt.
- Numerous DM raid target fixes and improvements.
- Add a new DM "unstriped" target that enables Intel to workaround
firmware limitations in some NVMe drives that are striped internally
(this target also works when stacked above the DM "striped" target).
- Various Documentation fixes and improvements.
- Misc cleanups and fixes across various DM infrastructure and targets
(e.g. bufio, flakey, log-writes, snapshot).
* tag 'for-4.16/dm-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm: (69 commits)
dm cache: Documentation: update default migration_throttling value
dm mpath selector: more evenly distribute ties
dm unstripe: fix target length versus number of stripes size check
dm thin: fix trailing semicolon in __remap_and_issue_shared_cell
dm table: fix NVMe bio-based dm_table_determine_type() validation
dm: various cleanups to md->queue initialization code
dm mpath: delay the retry of a request if the target responded as busy
dm mpath: return DM_MAPIO_DELAY_REQUEUE if QUEUE_IO or PG_INIT_REQUIRED
dm mpath: return DM_MAPIO_REQUEUE on blk-mq rq allocation failure
dm log writes: fix max length used for kstrndup
dm: backfill missing calls to mutex_destroy()
dm snapshot: use mutex instead of rw_semaphore
dm flakey: check for null arg_name in parse_features()
dm thin: extend thinpool status format string with omitted fields
dm thin: fixes in thin-provisioning.txt
dm thin: document representation of <highest mapped sector> when there is none
dm thin: fix documentation relative to low water mark threshold
dm cache: be consistent in specifying sectors and SI units in cache.txt
dm cache: delete obsoleted paragraph in cache.txt
dm cache: fix grammar in cache-policies.txt
...
DM is no longer prone to having its request_queue be improperly
initialized.
Summary of changes:
- defer DM's blk_register_queue() from add_disk()-time until
dm_setup_md_queue() by using add_disk_no_queue_reg() in alloc_dev().
- dm_setup_md_queue() is updated to fully initialize DM's request_queue
(_after_ all table loads have occurred and the request_queue's type,
features and limits are known).
A very welcome side-effect of these changes is DM no longer needs to:
1) backfill the "mq" sysfs entry (because historically DM didn't
initialize the request_queue to use blk-mq until _after_
blk_register_queue() was called via add_disk()).
2) call elv_register_queue() to get .request_fn request-based DM
device's "iosched" exposed in syfs.
In addition, blk-mq debugfs support is now made available because
request-based DM's blk-mq request_queue is now properly initialized
before dm_setup_md_queue() calls blk_register_queue().
These changes also stave off the need to introduce new DM-specific
workarounds in block core, e.g. this proposal:
https://patchwork.kernel.org/patch/10067961/
In the end DM devices should be less unicorn in nature (relative to
initialization and availability of block core infrastructure provided by
the request_queue).
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Tested-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
For BIO based DM, some targets aren't ready for dealing with bigger
incoming bio than 1Mbyte, such as crypt target.
Cc: Mike Snitzer <snitzer@redhat.com>
Cc:dm-devel@redhat.com
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Upper level bio-based drivers that stack immediately ontop of NVMe can
leverage direct_make_request(). In addition DM's NVMe bio-based
will initially only ever have one NVMe device that it submits IO to at a
time. There is no splitting needed. Enhance DM core so that
DM_TYPE_NVME_BIO_BASED's IO submission takes advantage of both of these
characteristics.
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
If dm_table_determine_type() establishes DM_TYPE_NVME_BIO_BASED then
all devices in the DM table do not support partial completions. Also,
the table has a single immutable target that doesn't require DM core to
split bios.
This will enable adding NVMe optimizations to bio-based DM.
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
No apparent need to generic_start_io_acct() until before the IO is ready
for submission. start_io_acct() is the proper place to do this
accounting -- it is also where DM accounts for pending IO and, if
enabled, starts dm-stats accounting.
Replace start_io_acct()'s part_round_stats() with generic_start_io_acct().
This eliminates needing to take part_stat_lock() multiple times when
starting an IO on bio-based devices.
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Eliminates need for a separate mempool to allocate 'struct dm_io'
objects from. As such, it saves an extra mempool allocation for each
original bio that DM core is issued.
This complicates the per-bio-data accessor functions by needing to
conditonally add extra padding to get to a target's per-bio-data. But
in the end this provides a decent performance improvement for all
bio-based DM devices.
On an NVMe-loop based testbed to a ramdisk (~3100 MB/s): bio-based
DM linear performance improved by 2% (went from 2665 to 2777 MB/s).
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
These CRUD comments have worn out their welcome. The code is what it
is, over time it'll hopefully get better. But these comments serve no
purpose whatsoever.
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
__send_changing_extent_only() must follow the same pattern that was
established with commit "dm: ensure bio submission follows a depth-first
tree walk". That is: submit first bio up to split boundary and then
split the remainder to further submissions.
Suggested-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
alloc_multiple_bios() assumes it can allocate the requested number of
bios but until now there was no gaurantee that the mempools would be
accomodating.
Suggested-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Now that all of DM has been revised and/or verified to no longer require
the use of BIOSET_NEED_RESCUER the dm_offload code may be removed.
Suggested-by: NeilBrown <neilb@suse.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
DM targets can request multiple bios be sent to them by DM core (see:
num_{flush,discard,write_same,write_zeroes}_bios). But until now these
bios were allocated in an unsafe manner than could potentially exhaust
the DM device's bioset -- in the face of multiple threads each trying to
do multiple allocations from the same DM device's bioset.
Fix __send_duplicate_bios() by using the new alloc_multiple_bios(). The
allocation strategy used by alloc_multiple_bios() models that used by
dm-crypt.c:crypt_alloc_buffer().
Neil Brown initially proposed this fix but the implementation has been
revised enough that it inappropriate to attribute the entirety of it to
him.
Suggested-by: NeilBrown <neilb@suse.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
No DM target provides num_write_bios and none has since dm-cache's
brief use in 2013.
Having the possibility of num_write_bios > 1 complicates bio
allocation. So remove the interface and assume there is only one bio
needed.
If a target ever needs more, it must provide a suitable bioset and
allocate itself based on its particular needs.
Signed-off-by: NeilBrown <neilb@suse.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
A dm device can, in general, represent a tree of targets, each of which
handles a sub-range of the range of blocks handled by the parent.
The bio sequencing managed by generic_make_request() requires that bios
are generated and handled in a depth-first manner. Each call to a
make_request_fn() may submit bios to a single member device, and may
submit bios for a reduced region of the same device as the
make_request_fn.
In particular, any bios submitted to member devices must be expected to
be processed in order, so a later one must never wait for an earlier
one.
This ordering is usually achieved by using bio_split() to reduce a bio
to a size that can be completely handled by one target, and resubmitting
the remainder to the originating device. bio_queue_split() shows the
canonical approach.
dm doesn't follow this approach, largely because it has needed to split
bios since long before bio_split() was available. It currently can
submit bios to separate targets within the one dm_make_request() call.
Dependencies between these targets, as can happen with dm-snap, can
cause deadlocks if either bios gets stuck behind the other in the queues
managed by generic_make_request(). This requires the 'rescue'
functionality provided by dm_offload_{start,end}.
Some of this requirement can be removed by changing the order of bio
submission to follow the canonical approach. That is, if dm finds that
it needs to split a bio, the remainder should be sent to
generic_make_request() rather than being handled immediately. This
delays the handling until the first part is completely processed, so the
deadlock problems do not occur.
__split_and_process_bio() can be called both from dm_make_request() and
from dm_wq_work(). When called from dm_wq_work() the current approach
is perfectly satisfactory as each bio will be processed immediately.
When called from dm_make_request(), current->bio_list will be non-NULL,
and in this case it is best to create a separate "clone" bio for the
remainder.
When we use bio_clone_bioset() to split off the front part of a bio
and chain the two together and submit the remainder to
generic_make_request(), it is important that the newly allocated
bio is used as the head to be processed immediately, and the original
bio gets "bio_advance()"d and sent to generic_make_request() as the
remainder. Otherwise, if the newly allocated bio is used as the
remainder, and if it then needs to be split again, then the next
bio_clone_bioset() call will be made while holding a reference a bio
(result of the first clone) from the same bioset. This can potentially
exhaust the bioset mempool and result in a memory allocation deadlock.
Note that there is no race caused by reassigning cio.io->bio after already
calling __map_bio(). This bio will only be dereferenced again after
dec_pending() has found io->io_count to be zero, and this cannot happen
before the dec_pending() call at the end of __split_and_process_bio().
To provide the clone bio when splitting, we use q->bio_split. This
was previously being freed by bio-based dm to avoid having excess
rescuer threads. As bio_split bio sets no longer create rescuer
threads, there is little cost and much gain from restoring the
q->bio_split bio set.
Signed-off-by: NeilBrown <neilb@suse.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Clarify that dm_accept_partial_bio isn't allowed for REQ_OP_ZONE_RESET
bios.
Signed-off-by: NeilBrown <neilb@suse.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
- A DM core fix for a race during device destruction that could result
in a BUG_ON.
- A stable@ fix for a DM cache race condition that could lead to data
corruption when operating in writeback mode (writethrough is default)
- Various DM cache cleanups and improvements
- Add DAX support to the DM log-writes target
- A fix for the DM zoned target's ability to deal with the last zone of
the drive being smaller than all others.
- A stable@ DM crypt and DM integrity fix for a negative check that was
to restrictive (prevented slab debug with XFS ontop of DM crypt from
working).
- A DM raid target fix for a panic that can occur when forcing a raid to
sync.
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Merge tag 'for-4.15/dm' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm
Pull device mapper updates from Mike Snitzer:
- a few conversions from atomic_t to ref_count_t
- a DM core fix for a race during device destruction that could result
in a BUG_ON
- a stable@ fix for a DM cache race condition that could lead to data
corruption when operating in writeback mode (writethrough is default)
- various DM cache cleanups and improvements
- add DAX support to the DM log-writes target
- a fix for the DM zoned target's ability to deal with the last zone of
the drive being smaller than all others
- a stable@ DM crypt and DM integrity fix for a negative check that was
to restrictive (prevented slab debug with XFS ontop of DM crypt from
working)
- a DM raid target fix for a panic that can occur when forcing a raid
to sync
* tag 'for-4.15/dm' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm: (25 commits)
dm cache: lift common migration preparation code to alloc_migration()
dm cache: remove usused deferred_cells member from struct cache
dm cache policy smq: allocate cache blocks in order
dm cache policy smq: change max background work from 10240 to 4096 blocks
dm cache background tracker: limit amount of background work that may be issued at once
dm cache policy smq: take origin idle status into account when queuing writebacks
dm cache policy smq: handle races with queuing background_work
dm raid: fix panic when attempting to force a raid to sync
dm integrity: allow unaligned bv_offset
dm crypt: allow unaligned bv_offset
dm: small cleanup in dm_get_md()
dm: fix race between dm_get_from_kobject() and __dm_destroy()
dm: allocate struct mapped_device with kvzalloc
dm zoned: ignore last smaller runt zone
dm space map metadata: use ARRAY_SIZE
dm log writes: add support for DAX
dm log writes: add support for inline data buffers
dm cache: simplify get_per_bio_data() by removing data_size argument
dm cache: remove all obsolete writethrough-specific code
dm cache: submit writethrough writes in parallel to origin and cache
...
Pull core block layer updates from Jens Axboe:
"This is the main pull request for block storage for 4.15-rc1.
Nothing out of the ordinary in here, and no API changes or anything
like that. Just various new features for drivers, core changes, etc.
In particular, this pull request contains:
- A patch series from Bart, closing the whole on blk/scsi-mq queue
quescing.
- A series from Christoph, building towards hidden gendisks (for
multipath) and ability to move bio chains around.
- NVMe
- Support for native multipath for NVMe (Christoph).
- Userspace notifications for AENs (Keith).
- Command side-effects support (Keith).
- SGL support (Chaitanya Kulkarni)
- FC fixes and improvements (James Smart)
- Lots of fixes and tweaks (Various)
- bcache
- New maintainer (Michael Lyle)
- Writeback control improvements (Michael)
- Various fixes (Coly, Elena, Eric, Liang, et al)
- lightnvm updates, mostly centered around the pblk interface
(Javier, Hans, and Rakesh).
- Removal of unused bio/bvec kmap atomic interfaces (me, Christoph)
- Writeback series that fix the much discussed hundreds of millions
of sync-all units. This goes all the way, as discussed previously
(me).
- Fix for missing wakeup on writeback timer adjustments (Yafang
Shao).
- Fix laptop mode on blk-mq (me).
- {mq,name} tupple lookup for IO schedulers, allowing us to have
alias names. This means you can use 'deadline' on both !mq and on
mq (where it's called mq-deadline). (me).
- blktrace race fix, oopsing on sg load (me).
- blk-mq optimizations (me).
- Obscure waitqueue race fix for kyber (Omar).
- NBD fixes (Josef).
- Disable writeback throttling by default on bfq, like we do on cfq
(Luca Miccio).
- Series from Ming that enable us to treat flush requests on blk-mq
like any other request. This is a really nice cleanup.
- Series from Ming that improves merging on blk-mq with schedulers,
getting us closer to flipping the switch on scsi-mq again.
- BFQ updates (Paolo).
- blk-mq atomic flags memory ordering fixes (Peter Z).
- Loop cgroup support (Shaohua).
- Lots of minor fixes from lots of different folks, both for core and
driver code"
* 'for-4.15/block' of git://git.kernel.dk/linux-block: (294 commits)
nvme: fix visibility of "uuid" ns attribute
blk-mq: fixup some comment typos and lengths
ide: ide-atapi: fix compile error with defining macro DEBUG
blk-mq: improve tag waiting setup for non-shared tags
brd: remove unused brd_mutex
blk-mq: only run the hardware queue if IO is pending
block: avoid null pointer dereference on null disk
fs: guard_bio_eod() needs to consider partitions
xtensa/simdisk: fix compile error
nvme: expose subsys attribute to sysfs
nvme: create 'slaves' and 'holders' entries for hidden controllers
block: create 'slaves' and 'holders' entries for hidden gendisks
nvme: also expose the namespace identification sysfs files for mpath nodes
nvme: implement multipath access to nvme subsystems
nvme: track shared namespaces
nvme: introduce a nvme_ns_ids structure
nvme: track subsystems
block, nvme: Introduce blk_mq_req_flags_t
block, scsi: Make SCSI quiesce and resume work reliably
block: Add the QUEUE_FLAG_PREEMPT_ONLY request queue flag
...
The following BUG_ON was hit when testing repeat creation and removal of
DM devices:
kernel BUG at drivers/md/dm.c:2919!
CPU: 7 PID: 750 Comm: systemd-udevd Not tainted 4.1.44
Call Trace:
[<ffffffff81649e8b>] dm_get_from_kobject+0x34/0x3a
[<ffffffff81650ef1>] dm_attr_show+0x2b/0x5e
[<ffffffff817b46d1>] ? mutex_lock+0x26/0x44
[<ffffffff811df7f5>] sysfs_kf_seq_show+0x83/0xcf
[<ffffffff811de257>] kernfs_seq_show+0x23/0x25
[<ffffffff81199118>] seq_read+0x16f/0x325
[<ffffffff811de994>] kernfs_fop_read+0x3a/0x13f
[<ffffffff8117b625>] __vfs_read+0x26/0x9d
[<ffffffff8130eb59>] ? security_file_permission+0x3c/0x44
[<ffffffff8117bdb8>] ? rw_verify_area+0x83/0xd9
[<ffffffff8117be9d>] vfs_read+0x8f/0xcf
[<ffffffff81193e34>] ? __fdget_pos+0x12/0x41
[<ffffffff8117c686>] SyS_read+0x4b/0x76
[<ffffffff817b606e>] system_call_fastpath+0x12/0x71
The bug can be easily triggered, if an extra delay (e.g. 10ms) is added
between the test of DMF_FREEING & DMF_DELETING and dm_get() in
dm_get_from_kobject().
To fix it, we need to ensure the test of DMF_FREEING & DMF_DELETING and
dm_get() are done in an atomic way, so _minor_lock is used.
The other callers of dm_get() have also been checked to be OK: some
callers invoke dm_get() under _minor_lock, some callers invoke it under
_hash_lock, and dm_start_request() invoke it after increasing
md->open_count.
Cc: stable@vger.kernel.org
Signed-off-by: Hou Tao <houtao1@huawei.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
The structure srcu_struct can be very big, its size is proportional to the
value CONFIG_NR_CPUS. The Fedora kernel has CONFIG_NR_CPUS 8192, the field
io_barrier in the struct mapped_device has 84kB in the debugging kernel
and 50kB in the non-debugging kernel. The large size may result in failure
of the function kzalloc_node.
In order to avoid the allocation failure, we use the function
kvzalloc_node, this function falls back to vmalloc if a large contiguous
chunk of memory is not available. This patch also moves the field
io_barrier to the last position of struct mapped_device - the reason is
that on many processor architectures, short memory offsets result in
smaller code than long memory offsets - on x86-64 it reduces code size by
320 bytes.
Note to stable kernel maintainers - the kernels 4.11 and older don't have
the function kvzalloc_node, you can use the function vzalloc_node instead.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Please do not apply this to mainline directly, instead please re-run the
coccinelle script shown below and apply its output.
For several reasons, it is desirable to use {READ,WRITE}_ONCE() in
preference to ACCESS_ONCE(), and new code is expected to use one of the
former. So far, there's been no reason to change most existing uses of
ACCESS_ONCE(), as these aren't harmful, and changing them results in
churn.
However, for some features, the read/write distinction is critical to
correct operation. To distinguish these cases, separate read/write
accessors must be used. This patch migrates (most) remaining
ACCESS_ONCE() instances to {READ,WRITE}_ONCE(), using the following
coccinelle script:
----
// Convert trivial ACCESS_ONCE() uses to equivalent READ_ONCE() and
// WRITE_ONCE()
// $ make coccicheck COCCI=/home/mark/once.cocci SPFLAGS="--include-headers" MODE=patch
virtual patch
@ depends on patch @
expression E1, E2;
@@
- ACCESS_ONCE(E1) = E2
+ WRITE_ONCE(E1, E2)
@ depends on patch @
expression E;
@@
- ACCESS_ONCE(E)
+ READ_ONCE(E)
----
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: davem@davemloft.net
Cc: linux-arch@vger.kernel.org
Cc: mpe@ellerman.id.au
Cc: shuah@kernel.org
Cc: snitzer@redhat.com
Cc: thor.thayer@linux.intel.com
Cc: tj@kernel.org
Cc: viro@zeniv.linux.org.uk
Cc: will.deacon@arm.com
Link: http://lkml.kernel.org/r/1508792849-3115-19-git-send-email-paulmck@linux.vnet.ibm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
atomic_t variables are currently used to implement reference
counters with the following properties:
- counter is initialized to 1 using atomic_set()
- a resource is freed upon counter reaching zero
- once counter reaches zero, its further
increments aren't allowed
- counter schema uses basic atomic operations
(set, inc, inc_not_zero, dec_and_test, etc.)
Such atomic variables should be converted to a newly provided
refcount_t type and API that prevents accidental counter overflows
and underflows. This is important since overflows and underflows
can lead to use-after-free situation and be exploitable.
The variable table_device.count is used as pure reference counter.
Convert it to refcount_t and fix up the operations.
Suggested-by: Kees Cook <keescook@chromium.org>
Reviewed-by: David Windsor <dwindsor@gmail.com>
Reviewed-by: Hans Liljestrand <ishkamiel@gmail.com>
Signed-off-by: Elena Reshetova <elena.reshetova@intel.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
We already have a queue_is_rq_based helper to check if a request_queue
is request based, so we can remove the flag for it.
Acked-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
The size of struct dm_name_list is different on 32-bit and 64-bit
kernels (so "(nl + 1)" differs between 32-bit and 64-bit kernels).
This mismatch caused some harmless difference in padding when using 32-bit
or 64-bit kernel. Commit 23d70c5e52 ("dm ioctl: report event number in
DM_LIST_DEVICES") added reporting event number in the output of
DM_LIST_DEVICES_CMD. This difference in padding makes it impossible for
userspace to determine the location of the event number (the location
would be different when running on 32-bit and 64-bit kernels).
Fix the padding by using offsetof(struct dm_name_list, name) instead of
sizeof(struct dm_name_list) to determine the location of entries.
Also, the ioctl version number is incremented to 37 so that userspace
can use the version number to determine that the event number is present
and correctly located.
In addition, a global event is now raised when a DM device is created,
removed, renamed or when table is swapped, so that the user can monitor
for device changes.
Reported-by: Eugene Syromiatnikov <esyr@redhat.com>
Fixes: 23d70c5e52 ("dm ioctl: report event number in DM_LIST_DEVICES")
Cc: stable@vger.kernel.org # 4.13
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
- 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
Commit abebfbe2f7 ("dm: add ->flush() dax operation support") is
buggy. A DM device may be composed of multiple underlying devices and
all of them need to be flushed. That commit just routes the flush
request to the first device and ignores the other devices.
It could be fixed by adding more complex logic to the device mapper. But
there is only one implementation of the method pmem_dax_ops->flush - that
is pmem_dax_flush() - and it calls arch_wb_cache_pmem(). Consequently, we
don't need the pmem_dax_ops->flush abstraction at all, we can call
arch_wb_cache_pmem() directly from dax_flush() because dax_dev->ops->flush
can't ever reach anything different from arch_wb_cache_pmem().
It should be also pointed out that for some uses of persistent memory it
is needed to flush only a very small amount of data (such as 1 cacheline),
and it would be overkill if we go through that device mapper machinery for
a single flushed cache line.
Fix this by removing the pmem_dax_ops->flush abstraction and call
arch_wb_cache_pmem() directly from dax_flush(). Also, remove the device
mapper code that forwards the flushes.
Fixes: abebfbe2f7 ("dm: add ->flush() dax operation support")
Cc: stable@vger.kernel.org
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Pull block layer updates from Jens Axboe:
"This is the first pull request for 4.14, containing most of the code
changes. It's a quiet series this round, which I think we needed after
the churn of the last few series. This contains:
- Fix for a registration race in loop, from Anton Volkov.
- Overflow complaint fix from Arnd for DAC960.
- Series of drbd changes from the usual suspects.
- Conversion of the stec/skd driver to blk-mq. From Bart.
- A few BFQ improvements/fixes from Paolo.
- CFQ improvement from Ritesh, allowing idling for group idle.
- A few fixes found by Dan's smatch, courtesy of Dan.
- A warning fixup for a race between changing the IO scheduler and
device remova. From David Jeffery.
- A few nbd fixes from Josef.
- Support for cgroup info in blktrace, from Shaohua.
- Also from Shaohua, new features in the null_blk driver to allow it
to actually hold data, among other things.
- Various corner cases and error handling fixes from Weiping Zhang.
- Improvements to the IO stats tracking for blk-mq from me. Can
drastically improve performance for fast devices and/or big
machines.
- Series from Christoph removing bi_bdev as being needed for IO
submission, in preparation for nvme multipathing code.
- Series from Bart, including various cleanups and fixes for switch
fall through case complaints"
* 'for-4.14/block' of git://git.kernel.dk/linux-block: (162 commits)
kernfs: checking for IS_ERR() instead of NULL
drbd: remove BIOSET_NEED_RESCUER flag from drbd_{md_,}io_bio_set
drbd: Fix allyesconfig build, fix recent commit
drbd: switch from kmalloc() to kmalloc_array()
drbd: abort drbd_start_resync if there is no connection
drbd: move global variables to drbd namespace and make some static
drbd: rename "usermode_helper" to "drbd_usermode_helper"
drbd: fix race between handshake and admin disconnect/down
drbd: fix potential deadlock when trying to detach during handshake
drbd: A single dot should be put into a sequence.
drbd: fix rmmod cleanup, remove _all_ debugfs entries
drbd: Use setup_timer() instead of init_timer() to simplify the code.
drbd: fix potential get_ldev/put_ldev refcount imbalance during attach
drbd: new disk-option disable-write-same
drbd: Fix resource role for newly created resources in events2
drbd: mark symbols static where possible
drbd: Send P_NEG_ACK upon write error in protocol != C
drbd: add explicit plugging when submitting batches
drbd: change list_for_each_safe to while(list_first_entry_or_null)
drbd: introduce drbd_recv_header_maybe_unplug
...
Using the same rate limiting state for different kinds of messages
is wrong because this can cause a high frequency message to suppress
a report of a low frequency message. Hence use a unique rate limiting
state per message type.
Fixes: 71a16736a1 ("dm: use local printk ratelimit")
Cc: stable@vger.kernel.org
Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
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>
No functional change in this patch, just in preparation for
basing the inflight mechanism on the queue in question.
Reviewed-by: Bart Van Assche <bart.vanassche@wdc.com>
Reviewed-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Pull more block updates from Jens Axboe:
"This is a followup for block changes, that didn't make the initial
pull request. It's a bit of a mixed bag, this contains:
- A followup pull request from Sagi for NVMe. Outside of fixups for
NVMe, it also includes a series for ensuring that we properly
quiesce hardware queues when browsing live tags.
- Set of integrity fixes from Dmitry (mostly), fixing various issues
for folks using DIF/DIX.
- Fix for a bug introduced in cciss, with the req init changes. From
Christoph.
- Fix for a bug in BFQ, from Paolo.
- Two followup fixes for lightnvm/pblk from Javier.
- Depth fix from Ming for blk-mq-sched.
- Also from Ming, performance fix for mtip32xx that was introduced
with the dynamic initialization of commands"
* 'for-linus' of git://git.kernel.dk/linux-block: (44 commits)
block: call bio_uninit in bio_endio
nvmet: avoid unneeded assignment of submit_bio return value
nvme-pci: add module parameter for io queue depth
nvme-pci: compile warnings in nvme_alloc_host_mem()
nvmet_fc: Accept variable pad lengths on Create Association LS
nvme_fc/nvmet_fc: revise Create Association descriptor length
lightnvm: pblk: remove unnecessary checks
lightnvm: pblk: control I/O flow also on tear down
cciss: initialize struct scsi_req
null_blk: fix error flow for shared tags during module_init
block: Fix __blkdev_issue_zeroout loop
nvme-rdma: unconditionally recycle the request mr
nvme: split nvme_uninit_ctrl into stop and uninit
virtio_blk: quiesce/unquiesce live IO when entering PM states
mtip32xx: quiesce request queues to make sure no submissions are inflight
nbd: quiesce request queues to make sure no submissions are inflight
nvme: kick requeue list when requeueing a request instead of when starting the queues
nvme-pci: quiesce/unquiesce admin_q instead of start/stop its hw queues
nvme-loop: quiesce/unquiesce admin_q instead of start/stop its hw queues
nvme-fc: quiesce/unquiesce admin_q instead of start/stop its hw queues
...
* Introduce the _flushcache() family of memory copy helpers and use them
for persistent memory write operations on x86. The _flushcache()
semantic indicates that the cache is either bypassed for the copy
operation (movnt) or any lines dirtied by the copy operation are
written back (clwb, clflushopt, or clflush).
* Extend dax_operations with ->copy_from_iter() and ->flush()
operations. These operations and other infrastructure updates allow
all persistent memory specific dax functionality to be pushed into
libnvdimm and the pmem driver directly. It also allows dax-specific
sysfs attributes to be linked to a host device, for example:
/sys/block/pmem0/dax/write_cache
* Add support for the new NVDIMM platform/firmware mechanisms introduced
in ACPI 6.2 and UEFI 2.7. This support includes the v1.2 namespace
label format, extensions to the address-range-scrub command set, new
error injection commands, and a new BTT (block-translation-table)
layout. These updates support inter-OS and pre-OS compatibility.
* Fix a longstanding memory corruption bug in nfit_test.
* Make the pmem and nvdimm-region 'badblocks' sysfs files poll(2)
capable.
* Miscellaneous fixes and small updates across libnvdimm and the nfit
driver.
Acknowledgements that came after the branch was pushed:
commit 6aa734a2f3 "libnvdimm, region, pmem: fix 'badblocks'
sysfs_get_dirent() reference lifetime"
Reviewed-by: Toshi Kani <toshi.kani@hpe.com>
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Merge tag 'libnvdimm-for-4.13' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm
Pull libnvdimm updates from Dan Williams:
"libnvdimm updates for the latest ACPI and UEFI specifications. This
pull request also includes new 'struct dax_operations' enabling to
undo the abuse of copy_user_nocache() for copy operations to pmem.
The dax work originally missed 4.12 to address concerns raised by Al.
Summary:
- Introduce the _flushcache() family of memory copy helpers and use
them for persistent memory write operations on x86. The
_flushcache() semantic indicates that the cache is either bypassed
for the copy operation (movnt) or any lines dirtied by the copy
operation are written back (clwb, clflushopt, or clflush).
- Extend dax_operations with ->copy_from_iter() and ->flush()
operations. These operations and other infrastructure updates allow
all persistent memory specific dax functionality to be pushed into
libnvdimm and the pmem driver directly. It also allows dax-specific
sysfs attributes to be linked to a host device, for example:
/sys/block/pmem0/dax/write_cache
- Add support for the new NVDIMM platform/firmware mechanisms
introduced in ACPI 6.2 and UEFI 2.7. This support includes the v1.2
namespace label format, extensions to the address-range-scrub
command set, new error injection commands, and a new BTT
(block-translation-table) layout. These updates support inter-OS
and pre-OS compatibility.
- Fix a longstanding memory corruption bug in nfit_test.
- Make the pmem and nvdimm-region 'badblocks' sysfs files poll(2)
capable.
- Miscellaneous fixes and small updates across libnvdimm and the nfit
driver.
Acknowledgements that came after the branch was pushed: commit
6aa734a2f3 ("libnvdimm, region, pmem: fix 'badblocks'
sysfs_get_dirent() reference lifetime") was reviewed by Toshi Kani
<toshi.kani@hpe.com>"
* tag 'libnvdimm-for-4.13' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm: (42 commits)
libnvdimm, namespace: record 'lbasize' for pmem namespaces
acpi/nfit: Issue Start ARS to retrieve existing records
libnvdimm: New ACPI 6.2 DSM functions
acpi, nfit: Show bus_dsm_mask in sysfs
libnvdimm, acpi, nfit: Add bus level dsm mask for pass thru.
acpi, nfit: Enable DSM pass thru for root functions.
libnvdimm: passthru functions clear to send
libnvdimm, btt: convert some info messages to warn/err
libnvdimm, region, pmem: fix 'badblocks' sysfs_get_dirent() reference lifetime
libnvdimm: fix the clear-error check in nsio_rw_bytes
libnvdimm, btt: fix btt_rw_page not returning errors
acpi, nfit: quiet invalid block-aperture-region warnings
libnvdimm, btt: BTT updates for UEFI 2.7 format
acpi, nfit: constify *_attribute_group
libnvdimm, pmem: disable dax flushing when pmem is fronting a volatile region
libnvdimm, pmem, dax: export a cache control attribute
dax: convert to bitmask for flags
dax: remove default copy_from_iter fallback
libnvdimm, nfit: enable support for volatile ranges
libnvdimm, pmem: fix persistence warning
...
events from multiple DM devices.
- Convert DM's printk macros over to using pr_<level> macros.
- Add a big-endian variant of plain64 IV to dm-crypt.
- Add support for zoned (aka SMR) devices to DM core. DM kcopyd was
also improved to provide a sequential write feature needed by zoned
devices.
- Introduce DM zoned target that provides support for host-managed zoned
devices, the result dm-zoned device acts as a drive-managed interface
to the underlying host-managed device.
- A DM raid fix to avoid using BUG() for error handling.
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Merge tag 'for-4.13/dm-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm
Pull device mapper updates from Mike Snitzer:
- Add the ability to use select or poll /dev/mapper/control to wait for
events from multiple DM devices.
- Convert DM's printk macros over to using pr_<level> macros.
- Add a big-endian variant of plain64 IV to dm-crypt.
- Add support for zoned (aka SMR) devices to DM core. DM kcopyd was
also improved to provide a sequential write feature needed by zoned
devices.
- Introduce DM zoned target that provides support for host-managed
zoned devices, the result dm-zoned device acts as a drive-managed
interface to the underlying host-managed device.
- A DM raid fix to avoid using BUG() for error handling.
* tag 'for-4.13/dm-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm:
dm zoned: fix overflow when converting zone ID to sectors
dm raid: stop using BUG() in __rdev_sectors()
dm zoned: drive-managed zoned block device target
dm kcopyd: add sequential write feature
dm linear: add support for zoned block devices
dm flakey: add support for zoned block devices
dm: introduce dm_remap_zone_report()
dm: fix REQ_OP_ZONE_REPORT bio handling
dm: fix REQ_OP_ZONE_RESET bio handling
dm table: add zoned block devices validation
dm: convert DM printk macros to pr_<level> macros
dm crypt: add big-endian variant of plain64 IV
dm bio prison: use rb_entry() rather than container_of()
dm ioctl: report event number in DM_LIST_DEVICES
dm ioctl: add a new DM_DEV_ARM_POLL ioctl
dm: add basic support for using the select or poll function
bio_integrity_trim inherent it's interface from bio_trim and accept
offset and size, but this API is error prone because data offset
must always be insync with bio's data offset. That is why we have
integrity update hook in bio_advance()
So only meaningful values are: offset == 0, sectors == bio_sectors(bio)
Let's just remove them completely.
Reviewed-by: Hannes Reinecke <hare@suse.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Now all queues allocators come without abounce limit by default,
dm doesn't have to override this anymore.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
A target driver support zoned block devices and exposing it as such may
receive REQ_OP_ZONE_REPORT request for the user to determine the mapped
device zone configuration. To process properly such request, the target
driver may need to remap the zone descriptors provided in the report
reply. The helper function dm_remap_zone_report() does this generically
using only the target start offset and length and the start offset
within the target device.
dm_remap_zone_report() will remap the start sector of all zones
reported. If the report includes sequential zones, the write pointer
position of these zones will also be remapped.
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Reviewed-by: Bart Van Assche <bart.vanassche@sandisk.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
A REQ_OP_ZONE_REPORT bio is not a medium access command. Its number of
sectors indicates the maximum size allowed for the report reply size and
not an amount of sectors accessed from the device. REQ_OP_ZONE_REPORT
bios should thus not be split depending on the target device maximum I/O
length but passed as-is. Note that it is the responsability of the
target to remap and format the report reply.
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Reviewed-by: Bart Van Assche <bart.vanassche@sandisk.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
The REQ_OP_ZONE_RESET bio has no payload and zero sectors. Its position
is the only information used to indicate the zone to reset on the
device. Due to its zero length, this bio is not cloned and sent to the
target through the non-flush case in __split_and_process_bio(). Add an
additional case in that function to call __split_and_process_non_flush()
without checking the clone info size.
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Reviewed-by: Bart Van Assche <bart.vanassche@sandisk.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Add the ability to poll on the /dev/mapper/control device. The select
or poll function waits until any event happens on any dm device since
opening the /dev/mapper/control device. When select or poll returns the
device as readable, we must close and reopen the device to wait for new
dm events.
Usage:
1. open the /dev/mapper/control device
2. scan the event numbers of all devices we are interested in and process
them
3. call select, poll or epoll on the handle (it waits until some new event
happens since opening the device)
4. close the /dev/mapper/control handle
5. go to step 1
The next commit allows to re-arm the polling without closing and
reopening the device.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Andy Grover <agrover@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
This patch converts bioset_create() to not create a workqueue by
default, so alloctions will never trigger punt_bios_to_rescuer(). It
also introduces a new flag BIOSET_NEED_RESCUER which tells
bioset_create() to preserve the old behavior.
All callers of bioset_create() that are inside block device drivers,
are given the BIOSET_NEED_RESCUER flag.
biosets used by filesystems or other top-level users do not
need rescuing as the bio can never be queued behind other
bios. This includes fs_bio_set, blkdev_dio_pool,
btrfs_bioset, xfs_ioend_bioset, and one allocated by
target_core_iblock.c.
biosets used by md/raid do not need rescuing as
their usage was recently audited and revised to never
risk deadlock.
It is hoped that most, if not all, of the remaining biosets
can end up being the non-rescued version.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Credit-to: Ming Lei <ming.lei@redhat.com> (minor fixes)
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: NeilBrown <neilb@suse.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
"flags" arguments are often seen as good API design as they allow
easy extensibility.
bioset_create_nobvec() is implemented internally as a variation in
flags passed to __bioset_create().
To support future extension, make the internal structure part of the
API.
i.e. add a 'flags' argument to bioset_create() and discard
bioset_create_nobvec().
Note that the bio_split allocations in drivers/md/raid* do not need
the bvec mempool - they should have used bioset_create_nobvec().
Suggested-by: Christoph Hellwig <hch@infradead.org>
Reviewed-by: Christoph Hellwig <hch@infradead.org>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: NeilBrown <neilb@suse.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Allow device-mapper to route flush operations to the
per-target implementation. In order for the device stacking to work we
need a dax_dev and a pgoff relative to that device. This gives each
layer of the stack the information it needs to look up the operation
pointer for the next level.
This conceptually allows for an array of mixed device drivers with
varying flush implementations.
Reviewed-by: Toshi Kani <toshi.kani@hpe.com>
Reviewed-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
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Merge tag 'v4.12-rc5' into for-4.13/block
We've already got a few conflicts and upcoming work depends on some of the
changes that have gone into mainline as regression fixes for this series.
Pull in 4.12-rc5 to resolve these conflicts and make it easier on down stream
trees to continue working on 4.13 changes.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Allow device-mapper to route copy_from_iter operations to the
per-target implementation. In order for the device stacking to work we
need a dax_dev and a pgoff relative to that device. This gives each
layer of the stack the information it needs to look up the operation
pointer for the next level.
This conceptually allows for an array of mixed device drivers with
varying copy_from_iter implementations.
Reviewed-by: Toshi Kani <toshi.kani@hpe.com>
Reviewed-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
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>
Turn the error paramter into a pointer so that target drivers can change
the value, and make sure only DM_ENDIO_* values are returned from the
methods.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Instead use the special DM_MAPIO_KILL return value to return -EIO just
like we do for the request based path. Note that dm-log-writes returned
-ENOMEM in a few places, which now becomes -EIO instead. No consumer
treats -ENOMEM special so this shouldn't be an issue (and it should
use a mempool to start with to make guaranteed progress).
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Commit b685d3d65a ("block: treat REQ_FUA and REQ_PREFLUSH as
synchronous") removed REQ_SYNC flag from WRITE_{FUA|PREFLUSH|...}
definitions. generic_make_request_checks() however strips REQ_FUA and
REQ_PREFLUSH flags from a bio when the storage doesn't report volatile
write cache and thus write effectively becomes asynchronous which can
lead to performance regressions.
Fix the problem by making sure all bios which are synchronous are
properly marked with REQ_SYNC.
Fixes: b685d3d65a ("block: treat REQ_FUA and REQ_PREFLUSH as synchronous")
Cc: stable@vger.kernel.org
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
* Region media error reporting: A libnvdimm region device is the parent
to one or more namespaces. To date, media errors have been reported via
the "badblocks" attribute attached to pmem block devices for namespaces
in "raw" or "memory" mode. Given that namespaces can be in "device-dax"
or "btt-sector" mode this new interface reports media errors
generically, i.e. independent of namespace modes or state. This
subsequently allows userspace tooling to craft "ACPI 6.1 Section
9.20.7.6 Function Index 4 - Clear Uncorrectable Error" requests and
submit them via the ioctl path for NVDIMM root bus devices.
* Introduce 'struct dax_device' and 'struct dax_operations': Prompted by
a request from Linus and feedback from Christoph this allows for dax
capable drivers to publish their own custom dax operations. This fixes
the broken assumption that all dax operations are related to a
persistent memory device, and makes it easier for other architectures
and platforms to add customized persistent memory support.
* 'libnvdimm' core updates: A new "deep_flush" sysfs attribute is
available for storage appliance applications to manually trigger memory
controllers to drain write-pending buffers that would otherwise be
flushed automatically by the platform ADR (asynchronous-DRAM-refresh)
mechanism at a power loss event. Support for "locked" DIMMs is included
to prevent namespaces from surfacing when the namespace label data area
is locked. Finally, fixes for various reported deadlocks and crashes,
also tagged for -stable.
* ACPI / nfit driver updates: General updates of the nfit driver to add
DSM command overrides, ACPI 6.1 health state flags support, DSM payload
debug available by default, and various fixes.
Acknowledgements that came after the branch was pushed:
commmit 565851c972 "device-dax: fix sysfs attribute deadlock"
Tested-by: Yi Zhang <yizhan@redhat.com>
commit 23f4984483 "libnvdimm: rework region badblocks clearing"
Tested-by: Toshi Kani <toshi.kani@hpe.com>
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Merge tag 'libnvdimm-for-4.12' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm
Pull libnvdimm updates from Dan Williams:
"The bulk of this has been in multiple -next releases. There were a few
late breaking fixes and small features that got added in the last
couple days, but the whole set has received a build success
notification from the kbuild robot.
Change summary:
- Region media error reporting: A libnvdimm region device is the
parent to one or more namespaces. To date, media errors have been
reported via the "badblocks" attribute attached to pmem block
devices for namespaces in "raw" or "memory" mode. Given that
namespaces can be in "device-dax" or "btt-sector" mode this new
interface reports media errors generically, i.e. independent of
namespace modes or state.
This subsequently allows userspace tooling to craft "ACPI 6.1
Section 9.20.7.6 Function Index 4 - Clear Uncorrectable Error"
requests and submit them via the ioctl path for NVDIMM root bus
devices.
- Introduce 'struct dax_device' and 'struct dax_operations': Prompted
by a request from Linus and feedback from Christoph this allows for
dax capable drivers to publish their own custom dax operations.
This fixes the broken assumption that all dax operations are
related to a persistent memory device, and makes it easier for
other architectures and platforms to add customized persistent
memory support.
- 'libnvdimm' core updates: A new "deep_flush" sysfs attribute is
available for storage appliance applications to manually trigger
memory controllers to drain write-pending buffers that would
otherwise be flushed automatically by the platform ADR
(asynchronous-DRAM-refresh) mechanism at a power loss event.
Support for "locked" DIMMs is included to prevent namespaces from
surfacing when the namespace label data area is locked. Finally,
fixes for various reported deadlocks and crashes, also tagged for
-stable.
- ACPI / nfit driver updates: General updates of the nfit driver to
add DSM command overrides, ACPI 6.1 health state flags support, DSM
payload debug available by default, and various fixes.
Acknowledgements that came after the branch was pushed:
- commmit 565851c972 "device-dax: fix sysfs attribute deadlock":
Tested-by: Yi Zhang <yizhan@redhat.com>
- commit 23f4984483 "libnvdimm: rework region badblocks clearing"
Tested-by: Toshi Kani <toshi.kani@hpe.com>"
* tag 'libnvdimm-for-4.12' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm: (52 commits)
libnvdimm, pfn: fix 'npfns' vs section alignment
libnvdimm: handle locked label storage areas
libnvdimm: convert NDD_ flags to use bitops, introduce NDD_LOCKED
brd: fix uninitialized use of brd->dax_dev
block, dax: use correct format string in bdev_dax_supported
device-dax: fix sysfs attribute deadlock
libnvdimm: restore "libnvdimm: band aid btt vs clear poison locking"
libnvdimm: fix nvdimm_bus_lock() vs device_lock() ordering
libnvdimm: rework region badblocks clearing
acpi, nfit: kill ACPI_NFIT_DEBUG
libnvdimm: fix clear length of nvdimm_forget_poison()
libnvdimm, pmem: fix a NULL pointer BUG in nd_pmem_notify
libnvdimm, region: sysfs trigger for nvdimm_flush()
libnvdimm: fix phys_addr for nvdimm_clear_poison
x86, dax, pmem: remove indirection around memcpy_from_pmem()
block: remove block_device_operations ->direct_access()
block, dax: convert bdev_dax_supported() to dax_direct_access()
filesystem-dax: convert to dax_direct_access()
Revert "block: use DAX for partition table reads"
ext2, ext4, xfs: retrieve dax_device for iomap operations
...
whether blocks should migrate to/from the cache. The bio-prison-v2
interface supports this improvement by enabling direct dispatch of
work to workqueues rather than having to delay the actual work
dispatch to the DM cache core. So the dm-cache policies are much more
nimble by being able to drive IO as they see fit. One immediate
benefit from the improved latency is a cache that should be much more
adaptive to changing workloads.
- Add a new DM integrity target that emulates a block device that has
additional per-sector tags that can be used for storing integrity
information.
- Add a new authenticated encryption feature to the DM crypt target that
builds on the capabilities provided by the DM integrity target.
- Add MD interface for switching the raid4/5/6 journal mode and update
the DM raid target to use it to enable aid4/5/6 journal write-back
support.
- Switch the DM verity target over to using the asynchronous hash crypto
API (this helps work better with architectures that have access to
off-CPU algorithm providers, which should reduce CPU utilization).
- Various request-based DM and DM multipath fixes and improvements from
Bart and Christoph.
- A DM thinp target fix for a bio structure leak that occurs for each
discard IFF discard passdown is enabled.
- A fix for a possible deadlock in DM bufio and a fix to re-check the
new buffer allocation watermark in the face of competing admin changes
to the 'max_cache_size_bytes' tunable.
- A couple DM core cleanups.
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Merge tag 'for-4.12/dm-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm
Pull device mapper updates from Mike Snitzer:
- A major update for DM cache that reduces the latency for deciding
whether blocks should migrate to/from the cache. The bio-prison-v2
interface supports this improvement by enabling direct dispatch of
work to workqueues rather than having to delay the actual work
dispatch to the DM cache core. So the dm-cache policies are much more
nimble by being able to drive IO as they see fit. One immediate
benefit from the improved latency is a cache that should be much more
adaptive to changing workloads.
- Add a new DM integrity target that emulates a block device that has
additional per-sector tags that can be used for storing integrity
information.
- Add a new authenticated encryption feature to the DM crypt target
that builds on the capabilities provided by the DM integrity target.
- Add MD interface for switching the raid4/5/6 journal mode and update
the DM raid target to use it to enable aid4/5/6 journal write-back
support.
- Switch the DM verity target over to using the asynchronous hash
crypto API (this helps work better with architectures that have
access to off-CPU algorithm providers, which should reduce CPU
utilization).
- Various request-based DM and DM multipath fixes and improvements from
Bart and Christoph.
- A DM thinp target fix for a bio structure leak that occurs for each
discard IFF discard passdown is enabled.
- A fix for a possible deadlock in DM bufio and a fix to re-check the
new buffer allocation watermark in the face of competing admin
changes to the 'max_cache_size_bytes' tunable.
- A couple DM core cleanups.
* tag 'for-4.12/dm-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm: (50 commits)
dm bufio: check new buffer allocation watermark every 30 seconds
dm bufio: avoid a possible ABBA deadlock
dm mpath: make it easier to detect unintended I/O request flushes
dm mpath: cleanup QUEUE_IF_NO_PATH bit manipulation by introducing assign_bit()
dm mpath: micro-optimize the hot path relative to MPATHF_QUEUE_IF_NO_PATH
dm: introduce enum dm_queue_mode to cleanup related code
dm mpath: verify __pg_init_all_paths locking assumptions at runtime
dm: verify suspend_locking assumptions at runtime
dm block manager: remove an unused argument from dm_block_manager_create()
dm rq: check blk_mq_register_dev() return value in dm_mq_init_request_queue()
dm mpath: delay requeuing while path initialization is in progress
dm mpath: avoid that path removal can trigger an infinite loop
dm mpath: split and rename activate_path() to prepare for its expanded use
dm ioctl: prevent stack leak in dm ioctl call
dm integrity: use previously calculated log2 of sectors_per_block
dm integrity: use hex2bin instead of open-coded variant
dm crypt: replace custom implementation of hex2bin()
dm crypt: remove obsolete references to per-CPU state
dm verity: switch to using asynchronous hash crypto API
dm crypt: use WQ_HIGHPRI for the IO and crypt workqueues
...
I/O errors triggered by multipathd incorrectly not enabling the no-flush
flag for DM_DEVICE_SUSPEND or DM_DEVICE_RESUME are hard to debug. Add
more logging to make it easier to debug this.
Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Introduce an enumeration type for the queue mode. This patch does
not change any functionality but makes the DM code easier to read.
Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Ensure that the assumptions about the caller holding suspend_lock
are checked at runtime if lockdep is enabled.
Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Now that all the producers and consumers of dax interfaces have been
converted to using dax_operations on a dax_device, remove the block
device direct_access enabling.
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Arrange for dm to lookup the dax services available from member devices.
Update the dax-capable targets, linear and stripe, to route dax
operations to the underlying device. Changes the target-internal
->direct_access() method to more closely align with the dax_operations
->direct_access() calling convention.
Cc: Toshi Kani <toshi.kani@hpe.com>
Reviewed-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
A dm-crypt on dm-integrity device incorrectly advertises an integrity
profile on the DM crypt device. It can be seen in the files
"/sys/block/dm-*/integrity/*" that both dm-integrity and dm-crypt target
advertise the integrity profile. That is incorrect, only the
dm-integrity target should advertise the integrity profile.
A general problem in DM is that if we have a DM device that depends on
another device with an integrity profile, the upper device will always
advertise the integrity profile, even when the target driver doesn't
support handling integrity data.
Most targets don't support integrity data, so we provide a whitelist of
targets that support it (linear, delay and striped). The targets that
support passing integrity data to the lower device are marked with the
flag DM_TARGET_PASSES_INTEGRITY. The DM core will now advertise
integrity data on a DM device only if all the targets support the
integrity data.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Allocate a dax_device to represent the capacity of a device-mapper
instance. Provide a ->direct_access() method via the new dax_operations
indirection that mirrors the functionality of the current direct_access
support via block_device_operations. Once fs/dax.c has been converted
to use dax_operations the old dm_blk_direct_access() will be removed.
A new helper dm_dax_get_live_target() is introduced to separate some of
the dm-specifics from the direct_access implementation.
This enabling is only for the top-level dm representation to upper
layers. Converting target direct_access implementations is deferred to a
separate patch.
Cc: Toshi Kani <toshi.kani@hpe.com>
Reviewed-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Copy & paste from the REQ_OP_WRITE_SAME code.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Currently only dm and md/raid5 bios trigger
trace_block_bio_complete(). Now that we have bio_chain() and
bio_inc_remaining(), it is not possible, in general, for a driver to
know when the bio is really complete. Only bio_endio() knows that.
So move the trace_block_bio_complete() call to bio_endio().
Now trace_block_bio_complete() pairs with trace_block_bio_queue().
Any bio for which a 'queue' event is traced, will subsequently
generate a 'complete' event.
There are a few cases where completion tracing is not wanted.
1/ If blk_update_request() has already generated a completion
trace event at the 'request' level, there is no point generating
one at the bio level too. In this case the bi_sector and bi_size
will have changed, so the bio level event would be wrong
2/ If the bio hasn't actually been queued yet, but is being aborted
early, then a trace event could be confusing. Some filesystems
call bio_endio() but do not want tracing.
3/ The bio_integrity code interposes itself by replacing bi_end_io,
then restoring it and calling bio_endio() again. This would produce
two identical trace events if left like that.
To handle these, we introduce a flag BIO_TRACE_COMPLETION and only
produce the trace event when this is set.
We address point 1 above by clearing the flag in blk_update_request().
We address point 2 above by only setting the flag when
generic_make_request() is called.
We address point 3 above by clearing the flag after generating a
completion event.
When bio_split() is used on a bio, particularly in blk_queue_split(),
there is an extra complication. A new bio is split off the front, and
may be handle directly without going through generic_make_request().
The old bio, which has been advanced, is passed to
generic_make_request(), so it will trigger a trace event a second
time.
Probably the best result when a split happens is to see a single
'queue' event for the whole bio, then multiple 'complete' events - one
for each component. To achieve this was can:
- copy the BIO_TRACE_COMPLETION flag to the new bio in bio_split()
- avoid generating a 'queue' event if BIO_TRACE_COMPLETION is already set.
This way, the split-off bio won't create a queue event, the original
won't either even if it re-submitted to generic_make_request(),
but both will produce completion events, each for their own range.
So if generic_make_request() is called (which generates a QUEUED
event), then bi_endio() will create a single COMPLETE event for each
range that the bio is split into, unless the driver has explicitly
requested it not to.
Signed-off-by: NeilBrown <neilb@suse.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Commit 79bd99596b ("blk: improve order of bio handling in generic_make_request()")
changed current->bio_list so that it did not contain *all* of the
queued bios, but only those submitted by the currently running
make_request_fn.
There are two places which walk the list and requeue selected bios,
and others that check if the list is empty. These are no longer
correct.
So redefine current->bio_list to point to an array of two lists, which
contain all queued bios, and adjust various code to test or walk both
lists.
Signed-off-by: NeilBrown <neilb@suse.com>
Fixes: 79bd99596b ("blk: improve order of bio handling in generic_make_request()")
Signed-off-by: Jens Axboe <axboe@fb.com>
Fix up affected files that include this signal functionality via sched.h.
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
tweaks.
- Add journal support to the DM raid target to close the 'write hole' on
raid 4/5/6.
- Fix dm-cache corruption, due to rounding bug, when cache exceeds 2TB.
- Add 'metadata2' feature to dm-cache to separate the dirty bitset out
from other cache metadata. This improves speed of shutting down
a large cache device (which implies writing out dirty bits).
- Fix a memory leak during dm-stats data structure destruction.
- Fix a DM multipath round-robin path selector performance regression
that was caused by less precise balancing across all paths.
- Lastly, introduce a DM core fix for a long-standing DM snapshot
deadlock that is rooted in the complexity of the device stack used in
conjunction with block core maintaining bios on current->bio_list to
manage recursion in generic_make_request(). A more comprehensive fix
to block core (and its hook in the cpu scheduler) would be wonderful
but this DM-specific fix is pragmatic considering how difficult it has
been to make progress on a generic fix.
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Merge tag 'dm-4.11-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm
Pull device mapper updates from Mike Snitzer:
- Fix dm-raid transient device failure processing and other smaller
tweaks.
- Add journal support to the DM raid target to close the 'write hole'
on raid 4/5/6.
- Fix dm-cache corruption, due to rounding bug, when cache exceeds 2TB.
- Add 'metadata2' feature to dm-cache to separate the dirty bitset out
from other cache metadata. This improves speed of shutting down a
large cache device (which implies writing out dirty bits).
- Fix a memory leak during dm-stats data structure destruction.
- Fix a DM multipath round-robin path selector performance regression
that was caused by less precise balancing across all paths.
- Lastly, introduce a DM core fix for a long-standing DM snapshot
deadlock that is rooted in the complexity of the device stack used in
conjunction with block core maintaining bios on current->bio_list to
manage recursion in generic_make_request(). A more comprehensive fix
to block core (and its hook in the cpu scheduler) would be wonderful
but this DM-specific fix is pragmatic considering how difficult it
has been to make progress on a generic fix.
* tag 'dm-4.11-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm: (22 commits)
dm: flush queued bios when process blocks to avoid deadlock
dm round robin: revert "use percpu 'repeat_count' and 'current_path'"
dm stats: fix a leaked s->histogram_boundaries array
dm space map metadata: constify dm_space_map structures
dm cache metadata: use cursor api in blocks_are_clean_separate_dirty()
dm persistent data: add cursor skip functions to the cursor APIs
dm cache metadata: use dm_bitset_new() to create the dirty bitset in format 2
dm bitset: add dm_bitset_new()
dm cache metadata: name the cache block that couldn't be loaded
dm cache metadata: add "metadata2" feature
dm cache metadata: use bitset cursor api to load discard bitset
dm bitset: introduce cursor api
dm btree: use GFP_NOFS in dm_btree_del()
dm space map common: memcpy the disk root to ensure it's arch aligned
dm block manager: add unlikely() annotations on dm_bufio error paths
dm cache: fix corruption seen when using cache > 2TB
dm raid: cleanup awkward branching in raid_message() option processing
dm raid: use mddev rather than rdev->mddev
dm raid: use read_disk_sb() throughout
dm raid: add raid4/5/6 journaling support
...
Commit df2cb6daa4 ("block: Avoid deadlocks with bio allocation by
stacking drivers") created a workqueue for every bio set and code
in bio_alloc_bioset() that tries to resolve some low-memory deadlocks
by redirecting bios queued on current->bio_list to the workqueue if the
system is low on memory. However other deadlocks (see below **) may
happen, without any low memory condition, because generic_make_request
is queuing bios to current->bio_list (rather than submitting them).
** the related dm-snapshot deadlock is detailed here:
https://www.redhat.com/archives/dm-devel/2016-July/msg00065.html
Fix this deadlock by redirecting any bios on current->bio_list to the
bio_set's rescue workqueue on every schedule() call. Consequently,
when the process blocks on a mutex, the bios queued on
current->bio_list are dispatched to independent workqueus and they can
complete without waiting for the mutex to be available.
The structure blk_plug contains an entry cb_list and this list can contain
arbitrary callback functions that are called when the process blocks.
To implement this fix DM (ab)uses the onstack plug's cb_list interface
to get its flush_current_bio_list() called at schedule() time.
This fixes the snapshot deadlock - if the map method blocks,
flush_current_bio_list() will be called and it redirects bios waiting
on current->bio_list to appropriate workqueues.
Fixes: https://bugzilla.redhat.com/show_bug.cgi?id=1267650
Depends-on: df2cb6daa4 ("block: Avoid deadlocks with bio allocation by stacking drivers")
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
