A bio segment may have partial interval block data with the rest
continuing into the next segments because direct-io data payloads only
need to align in memory to the device's DMA limits.
At the same time, the protection information may also be split in
multiple segments. The most likely way that may happen is if two
requests merge, or if we're directly using the io_uring user metadata.
The generate/verify, however, only ever accessed the first bip_vec.
Further, it may be possible to unalign the protection fields from the
user space buffer, or if there are odd additional opaque bytes in front
or in back of the protection information metadata region.
Change up the iteration to allow spanning multiple segments. This patch
is mostly a re-write of the protection information handling to allow any
arbitrary alignments, so it's probably easier to review the end result
rather than the diff.
Many controllers are not able to handle interval data composed of
multiple segments when PI is used, so this patch introduces a new
integrity limit that a low level driver can set to notify that it is
capable, default to false. The nvme driver is the first one to enable it
in this patch. Everyone else will force DMA alignment to the logical
block size as before to ensure interval data is always aligned within a
single segment.
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Keith Busch <kbusch@kernel.org>
Link: https://patch.msgid.link/20260313144701.1221652-2-kbusch@meta.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Various code assumes that the integrity interval is at least 1 sector
and evenly divides the logical block size. Add these checks to
blk_validate_integrity_limits(). This guards against block drivers that
report invalid interval_exp values.
Signed-off-by: Caleb Sander Mateos <csander@purestorage.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
The PI tuple must be contained within the metadata value, so validate
that pi_offset + pi_tuple_size <= metadata_size. This guards against
block drivers that report invalid pi_offset values.
Signed-off-by: Caleb Sander Mateos <csander@purestorage.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Pull block updates from Jens Axboe:
- Fix head insertion for mq-deadline, a regression from when priority
support was added
- Series simplifying and improving the ublk user copy code
- Various ublk related cleanups
- Fixup REQ_NOWAIT handling in loop/zloop, clearing NOWAIT when the
request is punted to a thread for handling
- Merge and then later revert loop dio nowait support, as it ended up
causing excessive stack usage for when the inline issue code needs to
dip back into the full file system code
- Improve auto integrity code, making it less deadlock prone
- Speedup polled IO handling, but manually managing the hctx lookups
- Fixes for blk-throttle for SSD devices
- Small series with fixes for the S390 dasd driver
- Add support for caching zones, avoiding unnecessary report zone
queries
- MD pull requests via Yu:
- fix null-ptr-dereference regression for dm-raid0
- fix IO hang for raid5 when array is broken with IO inflight
- remove legacy 1s delay to speed up system shutdown
- change maintainer's email address
- data can be lost if array is created with different lbs devices,
fix this problem and record lbs of the array in metadata
- fix rcu protection for md_thread
- fix mddev kobject lifetime regression
- enable atomic writes for md-linear
- some cleanups
- bcache updates via Coly
- remove useless discard and cache device code
- improve usage of per-cpu workqueues
- Reorganize the IO scheduler switching code, fixing some lockdep
reports as well
- Improve the block layer P2P DMA support
- Add support to the block tracing code for zoned devices
- Segment calculation improves, and memory alignment flexibility
improvements
- Set of prep and cleanups patches for ublk batching support. The
actual batching hasn't been added yet, but helps shrink down the
workload of getting that patchset ready for 6.20
- Fix for how the ps3 block driver handles segments offsets
- Improve how block plugging handles batch tag allocations
- nbd fixes for use-after-free of the configuration on device clear/put
- Set of improvements and fixes for zloop
- Add Damien as maintainer of the block zoned device code handling
- Various other fixes and cleanups
* tag 'for-6.19/block-20251201' of git://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux: (162 commits)
block/rnbd: correct all kernel-doc complaints
blk-mq: use queue_hctx in blk_mq_map_queue_type
md: remove legacy 1s delay in md_notify_reboot
md/raid5: fix IO hang when array is broken with IO inflight
md: warn about updating super block failure
md/raid0: fix NULL pointer dereference in create_strip_zones() for dm-raid
sbitmap: fix all kernel-doc warnings
ublk: add helper of __ublk_fetch()
ublk: pass const pointer to ublk_queue_is_zoned()
ublk: refactor auto buffer register in ublk_dispatch_req()
ublk: add `union ublk_io_buf` with improved naming
ublk: add parameter `struct io_uring_cmd *` to ublk_prep_auto_buf_reg()
kfifo: add kfifo_alloc_node() helper for NUMA awareness
blk-mq: fix potential uaf for 'queue_hw_ctx'
blk-mq: use array manage hctx map instead of xarray
ublk: prevent invalid access with DEBUG
s390/dasd: Use scnprintf() instead of sprintf()
s390/dasd: Move device name formatting into separate function
s390/dasd: Remove unnecessary debugfs_create() return checks
s390/dasd: Fix gendisk parent after copy pair swap
...
The current block layer automatic integrity protection allocates the
actual integrity buffer, which has three problems:
- because it happens at the bottom of the I/O stack and doesn't use a
mempool it can deadlock under load
- because the data size in a bio is almost unbounded when using lage
folios it can relatively easily exceed the maximum kmalloc size
- even when it does not exceed the maximum kmalloc size, it could
exceed the maximum segment size of the device
Fix this by limiting the I/O size so that we can allocate at least a
2MiB integrity buffer, i.e. 128MiB for 8 byte PI and 512 byte integrity
intervals, and create a mempool as a last resort for this maximum size,
mirroring the scheme used for bvecs. As a nice upside none of this
can fail now, so we remove the error handling and open code the
trivial addition of the bip vec.
The new allocation helpers sit outside of bio-integrity-auto.c because
I plan to reuse them for file system based PI in the near future.
Fixes: 7ba1ba12ee ("block: Block layer data integrity support")
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Anuj Gupta <anuj20.g@samsung.com>
Reviewed-by: Kanchan Joshi <joshi.k@samsung.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
The block layer PI generation / verification code expects the bio_vecs
to have at least LBA size (or more correctly integrity internal)
granularity. With the direct I/O alignment relaxation in 2022, user
space can now feed bios with less alignment than that, leading to
scribbling outside the PI buffers. Apparently this wasn't noticed so far
because none of the tests generate such buffers, but since 851c4c96db
("xfs: implement XFS_IOC_DIOINFO in terms of vfs_getattr"), xfstests
generic/013 by default generates such I/O now that the relaxed alignment
is advertised by the XFS_IOC_DIOINFO ioctl.
Fix this by increasing the required alignment when using PI, although
handling arbitrary alignment in the long run would be even nicer.
Fixes: bf8d08532b ("iomap: add support for dma aligned direct-io")
Fixes: b1a000d3b8 ("block: relax direct io memory alignment")
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Keith Busch <kbusch@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Despite its name, the block layer is fine with segments smaller that the
"min_segment_size" limit. The value is an optimization limit indicating
the largest segment that can be used without considering boundary
limits. Smaller segments can take a fast path, so give it a name that
reflects that: max_fast_segment_size.
Signed-off-by: Keith Busch <kbusch@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
blk_validate_atomic_write_limits() ensures that any boundary fits into
and is aligned to any chunk size.
However, it should also be possible to fit the chunk size into any
boundary. That check is already made in
blk_stack_atomic_writes_boundary_head().
Relax the check in blk_validate_atomic_write_limits() by reusing (and
renaming) blk_stack_atomic_writes_boundary_head().
Signed-off-by: John Garry <john.g.garry@oracle.com>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Atomic writes support may not always be possible when stacking devices
which support atomic writes. Such as case is a different atomic write
boundary between stacked devices (which is not supported).
In the case that atomic writes cannot supported, the top device queue HW
limits are set to 0.
However, in blk_stack_atomic_writes_limits(), we detect that we are
stacking the first bottom device by checking the top device
atomic_write_hw_max value == 0. This get confused with the case of atomic
writes not supported, above.
Make the distinction between stacking the first bottom device and no
atomics supported by initializing stacked device atomic_write_hw_max =
UINT_MAX and checking that for stacking the first bottom device.
Fixes: d7f36dc446 ("block: Support atomic writes limits for stacked devices")
Signed-off-by: John Garry <john.g.garry@oracle.com>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
In commit 63d092d1c1 ("block: use chunk_sectors when evaluating stacked
atomic write limits"), it was missed to use a chunk sectors limit check
in blk_stack_atomic_writes_boundary_head(), so update that function to
do the proper check.
Fixes: 63d092d1c1 ("block: use chunk_sectors when evaluating stacked atomic write limits")
Signed-off-by: John Garry <john.g.garry@oracle.com>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Documentation/ABI/stable/sysfs-block states:
What: /sys/block/<disk>/queue/discard_granularity
[...]
A discard_granularity of 0 means that the device does not support
discard functionality.
but this got broken when sorting out the block limits updates. Fix this
by setting the discard_granularity limit to zero when the combined
max_discard_sectors is zero.
Fixes: 3c407dc723 ("block: default the discard granularity to sector size")
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Link: https://lore.kernel.org/r/20250731152228.873923-1-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
For a device that does not advertize an optimal I/O size, the function
blk_apply_bdi_limits() defaults to an initial setting of the ra_pages
field of struct backing_dev_info to VM_READAHEAD_PAGES, that is, 128 KB.
This low I/O size value is far from being optimal for hard-disk devices:
when reading files from multiple contexts using buffered I/Os, the seek
overhead between the small read commands generated to read-ahead
multiple files will significantly limit the performance that can be
achieved.
This fact applies to all ATA devices as ATA does not define an optimal
I/O size and the SCSI SAT specification does not define a default value
to expose to the host.
Modify blk_apply_bdi_limits() to use a device max_sectors limit to
calculate the ra_pages field of struct backing_dev_info, when the device
is a rotational one (BLK_FEAT_ROTATIONAL feature is set). For a SCSI
disk, this defaults to 2560 KB, which significantly improve performance
for buffered reads. Using XFS and sequentially reading randomly selected
(large) files stored on a SATA HDD, the maximum throughput achieved with
8 readers reading files with 1MB buffered I/Os increases from 122 MB/s
to 167 MB/s (+36%). The improvement is even larger when reading files
using 128 KB buffered I/Os, with a throughput increasing from 57 MB/s to
165 MB/s (+189%).
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: John Garry <john.g.garry@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Link: https://lore.kernel.org/r/20250616062856.1629897-1-dlemoal@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Pull block updates from Jens Axboe:
- MD pull request via Yu:
- call del_gendisk synchronously (Xiao)
- cleanup unused variable (John)
- cleanup workqueue flags (Ryo)
- fix faulty rdev can't be removed during resync (Qixing)
- NVMe pull request via Christoph:
- try PCIe function level reset on init failure (Keith Busch)
- log TLS handshake failures at error level (Maurizio Lombardi)
- pci-epf: do not complete commands twice if nvmet_req_init()
fails (Rick Wertenbroek)
- misc cleanups (Alok Tiwari)
- Removal of the pktcdvd driver
This has been more than a decade coming at this point, and some
recently revealed breakages that had it causing issues even for cases
where it isn't required made me re-pull the trigger on this one. It's
known broken and nobody has stepped up to maintain the code
- Series for ublk supporting batch commands, enabling the use of
multishot where appropriate
- Speed up ublk exit handling
- Fix for the two-stage elevator fixing which could leak data
- Convert NVMe to use the new IOVA based API
- Increase default max transfer size to something more reasonable
- Series fixing write operations on zoned DM devices
- Add tracepoints for zoned block device operations
- Prep series working towards improving blk-mq queue management in the
presence of isolated CPUs
- Don't allow updating of the block size of a loop device that is
currently under exclusively ownership/open
- Set chunk sectors from stacked device stripe size and use it for the
atomic write size limit
- Switch to folios in bcache read_super()
- Fix for CD-ROM MRW exit flush handling
- Various tweaks, fixes, and cleanups
* tag 'for-6.17/block-20250728' of git://git.kernel.dk/linux: (94 commits)
block: restore two stage elevator switch while running nr_hw_queue update
cdrom: Call cdrom_mrw_exit from cdrom_release function
sunvdc: Balance device refcount in vdc_port_mpgroup_check
nvme-pci: try function level reset on init failure
dm: split write BIOs on zone boundaries when zone append is not emulated
block: use chunk_sectors when evaluating stacked atomic write limits
dm-stripe: limit chunk_sectors to the stripe size
md/raid10: set chunk_sectors limit
md/raid0: set chunk_sectors limit
block: sanitize chunk_sectors for atomic write limits
ilog2: add max_pow_of_two_factor()
nvmet: pci-epf: Do not complete commands twice if nvmet_req_init() fails
nvme-tcp: log TLS handshake failures at error level
docs: nvme: fix grammar in nvme-pci-endpoint-target.rst
nvme: fix typo in status code constant for self-test in progress
nvmet: remove redundant assignment of error code in nvmet_ns_enable()
nvme: fix incorrect variable in io cqes error message
nvme: fix multiple spelling and grammar issues in host drivers
block: fix blk_zone_append_update_request_bio() kernel-doc
md/raid10: fix set but not used variable in sync_request_write()
...
Pull vfs 'protection info' updates from Christian Brauner:
"This adds the new FS_IOC_GETLBMD_CAP ioctl() to query metadata and
protection info (PI) capabilities. This ioctl returns information
about the files integrity profile. This is useful for userspace
applications to understand a files end-to-end data protection support
and configure the I/O accordingly.
For now this interface is only supported by block devices. However the
design and placement of this ioctl in generic FS ioctl space allows us
to extend it to work over files as well. This maybe useful when
filesystems start supporting PI-aware layouts.
A new structure struct logical_block_metadata_cap is introduced, which
contains the following fields:
- lbmd_flags:
bitmask of logical block metadata capability flags
- lbmd_interval:
the amount of data described by each unit of logical block metadata
- lbmd_size:
size in bytes of the logical block metadata associated with each
interval
- lbmd_opaque_size:
size in bytes of the opaque block tag associated with each interval
- lbmd_opaque_offset:
offset in bytes of the opaque block tag within the logical block
metadata
- lbmd_pi_size:
size in bytes of the T10 PI tuple associated with each interval
- lbmd_pi_offset:
offset in bytes of T10 PI tuple within the logical block metadata
- lbmd_pi_guard_tag_type:
T10 PI guard tag type
- lbmd_pi_app_tag_size:
size in bytes of the T10 PI application tag
- lbmd_pi_ref_tag_size:
size in bytes of the T10 PI reference tag
- lbmd_pi_storage_tag_size:
size in bytes of the T10 PI storage tag
The internal logic to fetch the capability is encapsulated in a helper
function blk_get_meta_cap(), which uses the blk_integrity profile
associated with the device. The ioctl returns -EOPNOTSUPP, if
CONFIG_BLK_DEV_INTEGRITY is not enabled"
* tag 'vfs-6.17-rc1.integrity' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
block: fix lbmd_guard_tag_type assignment in FS_IOC_GETLBMD_CAP
block: fix FS_IOC_GETLBMD_CAP parsing in blkdev_common_ioctl()
fs: add ioctl to query metadata and protection info capabilities
nvme: set pi_offset only when checksum type is not BLK_INTEGRITY_CSUM_NONE
block: introduce pi_tuple_size field in blk_integrity
block: rename tuple_size field in blk_integrity to metadata_size
Currently we just ensure that a non-zero value in chunk_sectors aligns
with any atomic write boundary, as the blk boundary functionality uses
both these values.
However it is also improper to have atomic write unit max > chunk_sectors
(for non-zero chunk_sectors), as this would lead to splitting of atomic
write bios (which is disallowed).
Sanitize atomic write unit max against chunk_sectors to avoid any
potential problems.
Fixes: d00eea91de ("block: Add extra checks in blk_validate_atomic_write_limits()")
Reviewed-by: Nilay Shroff <nilay@linux.ibm.com>
Signed-off-by: John Garry <john.g.garry@oracle.com>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Link: https://lore.kernel.org/r/20250711105258.3135198-3-john.g.garry@oracle.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Introduce a new pi_tuple_size field in struct blk_integrity to
explicitly represent the size (in bytes) of the protection information
(PI) tuple. This is a prep patch.
Add validation in blk_validate_integrity_limits() to ensure that
pi size matches the expected size for known checksum types and never
exceeds the pi_tuple_size.
Suggested-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Anuj Gupta <anuj20.g@samsung.com>
Link: https://lore.kernel.org/20250630090548.3317-3-anuj20.g@samsung.com
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>
