kernel/linux.git/block/ioctl.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

block: implement async io_uring discard cmd

2024-09-11T16:45:28+00:00

io_uring allows implementing custom file specific asynchronous operations via the fops->uring_cmd callback, a.k.a. IORING_OP_URING_CMD requests or just io_uring commands. Use it to add support for async discards. Normally, it first tries to queue up bios in a non-blocking context, and if that fails, we'd retry from a blocking context by returning -EAGAIN to the core io_uring. We always get the result from bios asynchronously by setting a custom bi_end_io callback, at which point we drag the request into the task context to either reissue or complete it and post a completion to the user. Unlike ioctl(BLKDISCARD) with stronger guarantees against races, we only do a best effort attempt to invalidate page cache, and it can race with any writes and reads and leave page cache stale. It's the same kind of races we allow to direct writes. Also, apart from cases where discarding is not allowed at all, e.g. discards are not supported or the file/device is read only, the user should assume that the sector range on disk is not valid anymore, even when an error was returned to the user. Suggested-by: Conrad Meyer Signed-off-by: Pavel Begunkov Link: https://lore.kernel.org/r/2b5210443e4fa0257934f73dfafcc18a77cd0e09.1726072086.git.asml.silence@gmail.com Signed-off-by: Jens Axboe

block: introduce blk_validate_byte_range()

2024-09-11T16:45:07+00:00

In preparation to further changes extract a helper function out of blk_ioctl_discard() that validates if we can do IO against the given range of disk byte addresses. Signed-off-by: Pavel Begunkov Link: https://lore.kernel.org/r/19a7779323c71e742a2f511e4cf49efcfd68cfd4.1726072086.git.asml.silence@gmail.com Signed-off-by: Jens Axboe

block: fix integer overflow in BLKSECDISCARD

2024-09-04T14:01:30+00:00

I independently rediscovered commit 22d24a544b0d49bbcbd61c8c0eaf77d3c9297155 block: fix overflow in blk_ioctl_discard() but for secure erase. Same problem: uint64_t r[2] = {512, 18446744073709551104ULL}; ioctl(fd, BLKSECDISCARD, r); will enter near infinite loop inside blkdev_issue_secure_erase(): a.out: attempt to access beyond end of device loop0: rw=5, sector=3399043073, nr_sectors = 1024 limit=2048 bio_check_eod: 3286214 callbacks suppressed Signed-off-by: Alexey Dobriyan Link: https://lore.kernel.org/r/9e64057f-650a-46d1-b9f7-34af391536ef@p183 Signed-off-by: Jens Axboe

blk-lib: check for kill signal in ioctl BLKZEROOUT

2024-07-05T06:53:15+00:00

Zeroout can access a significant capacity and take longer than the user expected. A user may change their mind about wanting to run that command and attempt to kill the process and do something else with their device. But since the task is uninterruptable, they have to wait for it to finish, which could be many hours. Add a new BLKDEV_ZERO_KILLABLE flag for blkdev_issue_zeroout that checks for a fatal signal at each iteration so the user doesn't have to wait for their regretted operation to complete naturally. Heavily based on an earlier patch from Keith Busch. Signed-off-by: Christoph Hellwig Reviewed-by: Martin K. Petersen Link: https://lore.kernel.org/r/20240701165219.1571322-11-hch@lst.de 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()

Merge tag 'for-6.10/block-20240511' of git://git.kernel.dk/linux

2024-05-13T20:03:54+00:00

Pull block updates from Jens Axboe: - Add a partscan attribute in sysfs, fixing an issue with systemd relying on an internal interface that went away. - Attempt #2 at making long running discards interruptible. The previous attempt went into 6.9, but we ended up mostly reverting it as it had issues. - Remove old ida_simple API in bcache - Support for zoned write plugging, greatly improving the performance on zoned devices. - Remove the old throttle low interface, which has been experimental since 2017 and never made it beyond that and isn't being used. - Remove page->index debugging checks in brd, as it hasn't caught anything and prepares us for removing in struct page. - MD pull request from Song - Don't schedule block workers on isolated CPUs * tag 'for-6.10/block-20240511' of git://git.kernel.dk/linux: (84 commits) blk-throttle: delay initialization until configuration blk-throttle: remove CONFIG_BLK_DEV_THROTTLING_LOW block: fix that util can be greater than 100% block: support to account io_ticks precisely block: add plug while submitting IO bcache: fix variable length array abuse in btree_iter bcache: Remove usage of the deprecated ida_simple_xx() API md: Revert "md: Fix overflow in is_mddev_idle" blk-lib: check for kill signal in ioctl BLKDISCARD block: add a bio_await_chain helper block: add a blk_alloc_discard_bio helper block: add a bio_chain_and_submit helper block: move discard checks into the ioctl handler block: remove the discard_granularity check in __blkdev_issue_discard block/ioctl: prefer different overflow check null_blk: Fix the WARNING: modpost: missing MODULE_DESCRIPTION() block: fix and simplify blkdevparts= cmdline parsing block: refine the EOF check in blkdev_iomap_begin block: add a partscan sysfs attribute for disks block: add a disk_has_partscan helper ...

blk-lib: check for kill signal in ioctl BLKDISCARD

2024-05-07T13:29:42+00:00

Discards can access a significant capacity and take longer than the user expected. A user may change their mind about wanting to run that command and attempt to kill the process and do something else with their device. But since the task is uninterruptable, they have to wait for it to finish, which could be many hours. Open code blkdev_issue_discard in the BLKDISCARD ioctl handler and check for a fatal signal at each iteration so the user doesn't have to wait for their regretted operation to complete naturally. Heavily based on an earlier patch from Keith Busch. Reported-by: Conrad Meyer Signed-off-by: Christoph Hellwig Link: https://lore.kernel.org/r/20240506042027.2289826-7-hch@lst.de Signed-off-by: Jens Axboe