kernel/linux.git/block/bdev.c, branch v6.12.80

block: fix race between set_blocksize and read paths

2025-05-29T09:02:01+00:00

[ Upstream commit c0e473a0d226479e8e925d5ba93f751d8df628e9 ] With the new large sector size support, it's now the case that set_blocksize can change i_blksize and the folio order in a manner that conflicts with a concurrent reader and causes a kernel crash. Specifically, let's say that udev-worker calls libblkid to detect the labels on a block device. The read call can create an order-0 folio to read the first 4096 bytes from the disk. But then udev is preempted. Next, someone tries to mount an 8k-sectorsize filesystem from the same block device. The filesystem calls set_blksize, which sets i_blksize to 8192 and the minimum folio order to 1. Now udev resumes, still holding the order-0 folio it allocated. It then tries to schedule a read bio and do_mpage_readahead tries to create bufferheads for the folio. Unfortunately, blocks_per_folio == 0 because the page size is 4096 but the blocksize is 8192 so no bufferheads are attached and the bh walk never sets bdev. We then submit the bio with a NULL block device and crash. Therefore, truncate the page cache after flushing but before updating i_blksize. However, that's not enough -- we also need to lock out file IO and page faults during the update. Take both the i_rwsem and the invalidate_lock in exclusive mode for invalidations, and in shared mode for read/write operations. I don't know if this is the correct fix, but xfs/259 found it. Signed-off-by: Darrick J. Wong Reviewed-by: Christoph Hellwig Reviewed-by: Luis Chamberlain Tested-by: Shin'ichiro Kawasaki Link: https://lore.kernel.org/r/174543795699.4139148.2086129139322431423.stgit@frogsfrogsfrogs Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin

Merge tag 'for-6.12/block-20240925' of git://git.kernel.dk/linux

2024-09-25T21:56:40+00:00

Pull more block updates from Jens Axboe: - Improve blk-integrity segment counting and merging (Keith) - NVMe pull request via Keith: - Multipath fixes (Hannes) - Sysfs attribute list NULL terminate fix (Shin'ichiro) - Remove problematic read-back (Keith) - Fix for a regression with the IO scheduler switching freezing from 6.11 (Damien) - Use a raw spinlock for sbitmap, as it may get called from preempt disabled context (Ming) - Cleanup for bd_claiming waiting, using var_waitqueue() rather than the bit waitqueues, as that more accurately describes that it does (Neil) - Various cleanups (Kanchan, Qiu-ji, David) * tag 'for-6.12/block-20240925' of git://git.kernel.dk/linux: nvme: remove CC register read-back during enabling nvme: null terminate nvme_tls_attrs nvme-multipath: avoid hang on inaccessible namespaces nvme-multipath: system fails to create generic nvme device lib/sbitmap: define swap_lock as raw_spinlock_t block: Remove unused blk_limits_io_{min,opt} drbd: Fix atomicity violation in drbd_uuid_set_bm() block: Fix elv_iosched_local_module handling of "none" scheduler block: remove bogus union block: change wait on bd_claiming to use a var_waitqueue blk-integrity: improved sg segment mapping block: unexport blk_rq_count_integrity_sg nvme-rdma: use request to get integrity segments scsi: use request to get integrity segments block: provide a request helper for user integrity segments blk-integrity: consider entire bio list for merging blk-integrity: properly account for segments blk-mq: set the nr_integrity_segments from bio blk-mq: unconditional nr_integrity_segments

block: change wait on bd_claiming to use a var_waitqueue

2024-09-17T03:12:33+00:00

bd_prepare_to_claim() waits for a var to change, not for a bit to be cleared. Change from bit_waitqueue() to __var_waitqueue() and correspondingly use wake_up_var(). This will allow a future patch which change the "bit" function to expect an "unsigned long *" instead of "void *". Signed-off-by: NeilBrown Link: https://lore.kernel.org/r/20240826063659.15327-2-neilb@suse.de Signed-off-by: Jens Axboe

block,lsm: add LSM blob and new LSM hooks for block devices

2024-08-20T18:02:33+00:00

This patch introduces a new LSM blob to the block_device structure, enabling the security subsystem to store security-sensitive data related to block devices. Currently, for a device mapper's mapped device containing a dm-verity target, critical security information such as the roothash and its signing state are not readily accessible. Specifically, while the dm-verity volume creation process passes the dm-verity roothash and its signature from userspace to the kernel, the roothash is stored privately within the dm-verity target, and its signature is discarded post-verification. This makes it extremely hard for the security subsystem to utilize these data. With the addition of the LSM blob to the block_device structure, the security subsystem can now retain and manage important security metadata such as the roothash and the signing state of a dm-verity by storing them inside the blob. Access decisions can then be based on these stored data. The implementation follows the same approach used for security blobs in other structures like struct file, struct inode, and struct superblock. The initialization of the security blob occurs after the creation of the struct block_device, performed by the security subsystem. Similarly, the security blob is freed by the security subsystem before the struct block_device is deallocated or freed. This patch also introduces a new hook security_bdev_setintegrity() to save block device's integrity data to the new LSM blob. For example, for dm-verity, it can use this hook to expose its roothash and signing state to LSMs, then LSMs can save these data into the LSM blob. Please note that the new hook should be invoked every time the security information is updated to keep these data current. For example, in dm-verity, if the mapping table is reloaded and configured to use a different dm-verity target with a new roothash and signing information, the previously stored data in the LSM blob will become obsolete. It is crucial to re-invoke the hook to refresh these data and ensure they are up to date. This necessity arises from the design of device-mapper, where a device-mapper device is first created, and then targets are subsequently loaded into it. These targets can be modified multiple times during the device's lifetime. Therefore, while the LSM blob is allocated during the creation of the block device, its actual contents are not initialized at this stage and can change substantially over time. This includes alterations from data that the LSM 'trusts' to those it does not, making it essential to handle these changes correctly. Failure to address this dynamic aspect could potentially allow for bypassing LSM checks. Signed-off-by: Deven Bowers Signed-off-by: Fan Wu [PM: merge fuzz, subject line tweaks] Signed-off-by: Paul Moore

Merge tag 'for-6.11/block-20240710' of git://git.kernel.dk/linux

2024-07-15T21:20:22+00:00

Pull block updates from Jens Axboe: - NVMe updates via Keith: - Device initialization memory leak fixes (Keith) - More constants defined (Weiwen) - Target debugfs support (Hannes) - PCIe subsystem reset enhancements (Keith) - Queue-depth multipath policy (Redhat and PureStorage) - Implement get_unique_id (Christoph) - Authentication error fixes (Gaosheng) - MD updates via Song - sync_action fix and refactoring (Yu Kuai) - Various small fixes (Christoph Hellwig, Li Nan, and Ofir Gal, Yu Kuai, Benjamin Marzinski, Christophe JAILLET, Yang Li) - Fix loop detach/open race (Gulam) - Fix lower control limit for blk-throttle (Yu) - Add module descriptions to various drivers (Jeff) - Add support for atomic writes for block devices, and statx reporting for same. Includes SCSI and NVMe (John, Prasad, Alan) - Add IO priority information to block trace points (Dongliang) - Various zone improvements and tweaks (Damien) - mq-deadline tag reservation improvements (Bart) - Ignore direct reclaim swap writes in writeback throttling (Baokun) - Block integrity improvements and fixes (Anuj) - Add basic support for rust based block drivers. Has a dummy null_blk variant for now (Andreas) - Series converting driver settings to queue limits, and cleanups and fixes related to that (Christoph) - Cleanup for poking too deeply into the bvec internals, in preparation for DMA mapping API changes (Christoph) - Various minor tweaks and fixes (Jiapeng, John, Kanchan, Mikulas, Ming, Zhu, Damien, Christophe, Chaitanya) * tag 'for-6.11/block-20240710' of git://git.kernel.dk/linux: (206 commits) floppy: add missing MODULE_DESCRIPTION() macro loop: add missing MODULE_DESCRIPTION() macro ublk_drv: add missing MODULE_DESCRIPTION() macro xen/blkback: add missing MODULE_DESCRIPTION() macro block/rnbd: Constify struct kobj_type block: take offset into account in blk_bvec_map_sg again block: fix get_max_segment_size() warning loop: Don't bother validating blocksize virtio_blk: Don't bother validating blocksize null_blk: Don't bother validating blocksize block: Validate logical block size in blk_validate_limits() virtio_blk: Fix default logical block size fallback nvmet-auth: fix nvmet_auth hash error handling nvme: implement ->get_unique_id block: pass a phys_addr_t to get_max_segment_size block: add a bvec_phys helper blk-lib: check for kill signal in ioctl BLKZEROOUT block: limit the Write Zeroes to manually writing zeroes fallback block: refacto blkdev_issue_zeroout block: move read-only and supported checks into (__)blkdev_issue_zeroout ...

block: Add atomic write support for statx

2024-06-20T21:19:17+00:00

Extend statx system call to return additional info for atomic write support support if the specified file is a block device. Reviewed-by: Martin K. Petersen Signed-off-by: Prasad Singamsetty Signed-off-by: John Garry Reviewed-by: Keith Busch Acked-by: Darrick J. Wong Reviewed-by: Darrick J. Wong Reviewed-by: Luis Chamberlain Link: https://lore.kernel.org/r/20240620125359.2684798-7-john.g.garry@oracle.com Signed-off-by: Jens Axboe

bdev: make blockdev_mnt static

2024-06-16T21:29:55+00:00

The blockdev_mnt are not used outside the file bdev.c, so the modification is defined as static. block/bdev.c:377:17: warning: symbol 'blockdev_mnt' was not declared. Should it be static? Reported-by: Abaci Robot jpg: Remove closes bugzilla link Reviewed-by: Christoph Hellwig Signed-off-by: Jiapeng Chong Signed-off-by: John Garry Reviewed-by: Bart Van Assche Fixes: 8f3a608827d1 ("bdev: open block device as files") Tested-by: John Garry Link: https://lore.kernel.org/r/20240614090345.655716-2-john.g.garry@oracle.com Signed-off-by: Jens Axboe

Merge tag 'pull-bd_flags-2' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

2024-05-21T20:02:56+00:00

Pull bdev flags update from Al Viro: "Compactifying bdev flags. We can easily have up to 24 flags with sane atomicity, _without_ pushing anything out of the first cacheline of struct block_device" * tag 'pull-bd_flags-2' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: bdev: move ->bd_make_it_fail to ->__bd_flags bdev: move ->bd_ro_warned to ->__bd_flags bdev: move ->bd_has_subit_bio to ->__bd_flags bdev: move ->bd_write_holder into ->__bd_flags bdev: move ->bd_read_only to ->__bd_flags bdev: infrastructure for flags wrapper for access to ->bd_partno Use bdev_is_paritition() instead of open-coding it

Merge tag 'pull-bd_inode-1' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

2024-05-21T16:51:42+00:00

Pull bdev bd_inode updates from Al Viro: "Replacement of bdev->bd_inode with sane(r) set of primitives by me and Yu Kuai" * tag 'pull-bd_inode-1' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: RIP ->bd_inode dasd_format(): killing the last remaining user of ->bd_inode nilfs_attach_log_writer(): use ->bd_mapping->host instead of ->bd_inode block/bdev.c: use the knowledge of inode/bdev coallocation gfs2: more obvious initializations of mapping->host fs/buffer.c: massage the remaining users of ->bd_inode to ->bd_mapping blk_ioctl_{discard,zeroout}(): we only want ->bd_inode->i_mapping here... grow_dev_folio(): we only want ->bd_inode->i_mapping there use ->bd_mapping instead of ->bd_inode->i_mapping block_device: add a pointer to struct address_space (page cache of bdev) missing helpers: bdev_unhash(), bdev_drop() block: move two helpers into bdev.c block2mtd: prevent direct access of bd_inode dm-vdo: use bdev_nr_bytes(bdev) instead of i_size_read(bdev->bd_inode) blkdev_write_iter(): saner way to get inode and bdev bcachefs: remove dead function bdev_sectors() ext4: remove block_device_ejected() erofs_buf: store address_space instead of inode erofs: switch erofs_bread() to passing offset instead of block number

Merge tag 'pull-set_blocksize' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

2024-05-21T15:34:51+00:00

Pull vfs blocksize updates from Al Viro: "This gets rid of bogus set_blocksize() uses, switches it over to be based on a 'struct file *' and verifies that the caller has the device opened exclusively" * tag 'pull-set_blocksize' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: make set_blocksize() fail unless block device is opened exclusive set_blocksize(): switch to passing struct file * btrfs_get_bdev_and_sb(): call set_blocksize() only for exclusive opens swsusp: don't bother with setting block size zram: don't bother with reopening - just use O_EXCL for open swapon(2): open swap with O_EXCL swapon(2)/swapoff(2): don't bother with block size pktcdvd: sort set_blocksize() calls out bcache_register(): don't bother with set_blocksize()