kernel/linux.git/drivers/md/dm-thin.c, branch v6.12.80

dm thin: make get_first_thin use rcu-safe list first function

2025-01-17T12:40:45+00:00

commit 80f130bfad1dab93b95683fc39b87235682b8f72 upstream. The documentation in rculist.h explains the absence of list_empty_rcu() and cautions programmers against relying on a list_empty() -> list_first() sequence in RCU safe code. This is because each of these functions performs its own READ_ONCE() of the list head. This can lead to a situation where the list_empty() sees a valid list entry, but the subsequent list_first() sees a different view of list head state after a modification. In the case of dm-thin, this author had a production box crash from a GP fault in the process_deferred_bios path. This function saw a valid list head in get_first_thin() but when it subsequently dereferenced that and turned it into a thin_c, it got the inside of the struct pool, since the list was now empty and referring to itself. The kernel on which this occurred printed both a warning about a refcount_t being saturated, and a UBSAN error for an out-of-bounds cpuid access in the queued spinlock, prior to the fault itself. When the resulting kdump was examined, it was possible to see another thread patiently waiting in thin_dtr's synchronize_rcu. The thin_dtr call managed to pull the thin_c out of the active thins list (and have it be the last entry in the active_thins list) at just the wrong moment which lead to this crash. Fortunately, the fix here is straight forward. Switch get_first_thin() function to use list_first_or_null_rcu() which performs just a single READ_ONCE() and returns NULL if the list is already empty. This was run against the devicemapper test suite's thin-provisioning suites for delete and suspend and no regressions were observed. Signed-off-by: Krister Johansen Fixes: b10ebd34ccca ("dm thin: fix rcu_read_lock being held in code that can sleep") Cc: stable@vger.kernel.org Acked-by: Ming-Hung Tsai Signed-off-by: Mikulas Patocka Signed-off-by: Greg Kroah-Hartman

dm thin: Add missing destroy_work_on_stack()

2024-12-09T09:41:08+00:00

commit e74fa2447bf9ed03d085b6d91f0256cc1b53f1a8 upstream. This commit add missed destroy_work_on_stack() operations for pw->worker in pool_work_wait(). Fixes: e7a3e871d895 ("dm thin: cleanup noflush_work to use a proper completion") Cc: stable@vger.kernel.org Signed-off-by: Yuan Can Signed-off-by: Mikulas Patocka Signed-off-by: Greg Kroah-Hartman

dm: Convert to use ERR_CAST()

2024-09-02T09:41:11+00:00

Use ERR_CAST() as it is designed for casting an error pointer to another type. This macro utilizes the __force and __must_check modifiers, which instruct the compiler to verify for errors at the locations where it is employed. Signed-off-by: Yuesong Li Signed-off-by: Mikulas Patocka

dm: stop using blk_limits_io_{min,opt}

2024-07-10T11:10:06+00:00

Remove use of the blk_limits_io_{min,opt} and assign the values directly to the queue_limits structure. For the io_opt this is a completely mechanical change, for io_min it removes flooring the limit to the physical and logical block size in the particular caller. But as blk_validate_limits will do the same later when actually applying the limits, there still is no change in overall behavior. Signed-off-by: Christoph Hellwig Signed-off-by: Mikulas Patocka

Merge tag 'for-6.10/dm-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm

2024-05-21T18:43:11+00:00

Pull device mapper fixes from Mike Snitzer: - Fix DM discard regressions due to DM core switching over to using queue_limits_set() without DM core and targets first being updated to set (and stack) discard limits in terms of max_hw_discard_sectors and not max_discard_sectors - Fix stable@ DM integrity discard support to set device's discard_granularity limit to the device's logical block size * tag 'for-6.10/dm-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm: dm: always manage discard support in terms of max_hw_discard_sectors dm-integrity: set discard_granularity to logical block size

dm: always manage discard support in terms of max_hw_discard_sectors

2024-05-20T19:51:19+00:00

Commit 4f563a64732d ("block: add a max_user_discard_sectors queue limit") changed block core to set max_discard_sectors to: min(lim->max_hw_discard_sectors, lim->max_user_discard_sectors) Since commit 1c0e720228ad ("dm: use queue_limits_set") it was reported dm-thinp was failing in a few fstests (generic/347 and generic/405) with the first WARN_ON_ONCE in dm_cell_key_has_valid_range() being reported, e.g.: WARNING: CPU: 1 PID: 30 at drivers/md/dm-bio-prison-v1.c:128 dm_cell_key_has_valid_range+0x3d/0x50 blk_set_stacking_limits() sets max_user_discard_sectors to UINT_MAX, so given how block core now sets max_discard_sectors (detailed above) it follows that blk_stack_limits() stacks up the underlying device's max_hw_discard_sectors and max_discard_sectors is set to match it. If max_hw_discard_sectors exceeds dm's BIO_PRISON_MAX_RANGE, then dm_cell_key_has_valid_range() will trigger the warning with: WARN_ON_ONCE(key->block_end - key->block_begin > BIO_PRISON_MAX_RANGE) Aside from this warning, the discard will fail. Fix this and other DM issues by governing discard support in terms of max_hw_discard_sectors instead of max_discard_sectors. Reported-by: Theodore Ts'o Fixes: 1c0e720228ad ("dm: use queue_limits_set") Signed-off-by: Mike Snitzer

dm: use bio_list_merge_init

2024-04-01T17:53:37+00:00

Use bio_list_merge_init instead of open coding bio_list_merge and bio_list_init. Signed-off-by: Christoph Hellwig Reviewed-by: Mike Snitzer Reviewed-by: Johannes Thumshirn Reviewed-by: Damien Le Moal Link: https://lore.kernel.org/r/20240328084147.2954434-4-hch@lst.de Signed-off-by: Jens Axboe

dm: update relevant MODULE_AUTHOR entries to latest dm-devel mailing list

2024-02-20T19:22:55+00:00

Signed-off-by: Mike Snitzer

dm thin: add braces around conditional code that spans lines

2024-02-20T18:37:31+00:00

Signed-off-by: Mike Snitzer

Merge tag 'for-6.5/dm-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm

2023-06-30T19:16:00+00:00

Pull device mapper updates from Mike Snitzer: - Update DM crypt to allocate compound pages if possible - Fix DM crypt target's crypt_ctr_cipher_new return value on invalid AEAD cipher - Fix DM flakey testing target's write bio corruption feature to corrupt the data of a cloned bio instead of the original - Add random_read_corrupt and random_write_corrupt features to DM flakey target - Fix ABBA deadlock in DM thin metadata by resetting associated bufio client rather than destroying and recreating it - A couple other small DM thinp cleanups - Update DM core to support disabling block core IO stats accounting and optimize away code that isn't needed if stats are disabled - Other small DM core cleanups - Improve DM integrity target to not require so much memory on 32 bit systems. Also only allocate the recalculate buffer as needed (and increasingly reduce its size on allocation failure) - Update DM integrity to use %*ph for printing hexdump of a small buffer. Also update DM integrity documentation - Various DM core ioctl interface hardening. Now more careful about alignment of structures and processing of input passed to the kernel from userspace. Also disallow the creation of DM devices named "control", "." or ".." - Eliminate GFP_NOIO workarounds for __vmalloc and kvmalloc in DM core's ioctl and bufio code * tag 'for-6.5/dm-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm: (28 commits) dm: get rid of GFP_NOIO workarounds for __vmalloc and kvmalloc dm integrity: scale down the recalculate buffer if memory allocation fails dm integrity: only allocate recalculate buffer when needed dm integrity: reduce vmalloc space footprint on 32-bit architectures dm ioctl: Refuse to create device named "." or ".." dm ioctl: Refuse to create device named "control" dm ioctl: Avoid double-fetch of version dm ioctl: structs and parameter strings must not overlap dm ioctl: Avoid pointer arithmetic overflow dm ioctl: Check dm_target_spec is sufficiently aligned Documentation: dm-integrity: Document an example of how the tunables relate. Documentation: dm-integrity: Document default values. Documentation: dm-integrity: Document the meaning of "buffer". Documentation: dm-integrity: Fix minor grammatical error. dm integrity: Use %*ph for printing hexdump of a small buffer dm thin: disable discards for thin-pool if no_discard_passdown dm: remove stale/redundant dm_internal_{suspend,resume} prototypes in dm.h dm: skip dm-stats work in alloc_io() unless needed dm: avoid needless dm_io access if all IO accounting is disabled dm: support turning off block-core's io stats accounting ...