kernel/linux.git/drivers/md/dm-thin.c, branch v6.6.132

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

2025-01-17T12:36:17+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()

2024-12-09T09:33:08+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

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 ...

Merge tag 'for-6.5/block-2023-06-23' of git://git.kernel.dk/linux

2023-06-26T19:47:20+00:00

Pull block updates from Jens Axboe: - NVMe pull request via Keith: - Various cleanups all around (Irvin, Chaitanya, Christophe) - Better struct packing (Christophe JAILLET) - Reduce controller error logs for optional commands (Keith) - Support for >=64KiB block sizes (Daniel Gomez) - Fabrics fixes and code organization (Max, Chaitanya, Daniel Wagner) - bcache updates via Coly: - Fix a race at init time (Mingzhe Zou) - Misc fixes and cleanups (Andrea, Thomas, Zheng, Ye) - use page pinning in the block layer for dio (David) - convert old block dio code to page pinning (David, Christoph) - cleanups for pktcdvd (Andy) - cleanups for rnbd (Guoqing) - use the unchecked __bio_add_page() for the initial single page additions (Johannes) - fix overflows in the Amiga partition handling code (Michael) - improve mq-deadline zoned device support (Bart) - keep passthrough requests out of the IO schedulers (Christoph, Ming) - improve support for flush requests, making them less special to deal with (Christoph) - add bdev holder ops and shutdown methods (Christoph) - fix the name_to_dev_t() situation and use cases (Christoph) - decouple the block open flags from fmode_t (Christoph) - ublk updates and cleanups, including adding user copy support (Ming) - BFQ sanity checking (Bart) - convert brd from radix to xarray (Pankaj) - constify various structures (Thomas, Ivan) - more fine grained persistent reservation ioctl capability checks (Jingbo) - misc fixes and cleanups (Arnd, Azeem, Demi, Ed, Hengqi, Hou, Jan, Jordy, Li, Min, Yu, Zhong, Waiman) * tag 'for-6.5/block-2023-06-23' of git://git.kernel.dk/linux: (266 commits) scsi/sg: don't grab scsi host module reference ext4: Fix warning in blkdev_put() block: don't return -EINVAL for not found names in devt_from_devname cdrom: Fix spectre-v1 gadget block: Improve kernel-doc headers blk-mq: don't insert passthrough request into sw queue bsg: make bsg_class a static const structure ublk: make ublk_chr_class a static const structure aoe: make aoe_class a static const structure block/rnbd: make all 'class' structures const block: fix the exclusive open mask in disk_scan_partitions block: add overflow checks for Amiga partition support block: change all __u32 annotations to __be32 in affs_hardblocks.h block: fix signed int overflow in Amiga partition support block: add capacity validation in bdev_add_partition() block: fine-granular CAP_SYS_ADMIN for Persistent Reservation block: disallow Persistent Reservation on partitions reiserfs: fix blkdev_put() warning from release_journal_dev() block: fix wrong mode for blkdev_get_by_dev() from disk_scan_partitions() block: document the holder argument to blkdev_get_by_path ...

dm thin: disable discards for thin-pool if no_discard_passdown

2023-06-16T22:24:14+00:00

Also rename disable_passdown_if_not_supported to disable_discard_passdown_if_not_supported. And fold passdown_enabled() into only caller. Signed-off-by: Mike Snitzer

dm thin: update .io_hints methods to not require handling discards last

2023-06-16T22:24:13+00:00

Removes assumptions about what might follow the discard setup code (previously the code would return early if discards not enabled). Makes it possible to add more capabilites to the end of each .io_hints method (which is the natural thing to do when adding new features). Signed-off-by: Mike Snitzer

dm thin: remove return code variable in pool_map

2023-06-16T22:24:13+00:00

Always returns DM_MAPIO_REMAPPED so no need for variable. Signed-off-by: Mike Snitzer

dm thin: fix issue_discard to pass GFP_NOIO to __blkdev_issue_discard

2023-06-15T16:46:59+00:00

issue_discard() passes GFP_NOWAIT to __blkdev_issue_discard() despite its code assuming bio_alloc() always succeeds. Commit 3dba53a958a75 ("dm thin: use __blkdev_issue_discard for async discard support") clearly shows where things went bad: Before commit 3dba53a958a75, dm-thin.c's open-coded __blkdev_issue_discard_async() properly handled using GFP_NOWAIT. Unfortunately __blkdev_issue_discard() doesn't and it was missed during review. Cc: stable@vger.kernel.org Signed-off-by: Mike Snitzer

block: replace fmode_t with a block-specific type for block open flags

2023-06-12T14:04:05+00:00

The only overlap between the block open flags mapped into the fmode_t and other uses of fmode_t are FMODE_READ and FMODE_WRITE. Define a new blk_mode_t instead for use in blkdev_get_by_{dev,path}, ->open and ->ioctl and stop abusing fmode_t. Signed-off-by: Christoph Hellwig Acked-by: Jack Wang [rnbd] Reviewed-by: Hannes Reinecke Reviewed-by: Christian Brauner Link: https://lore.kernel.org/r/20230608110258.189493-28-hch@lst.de Signed-off-by: Jens Axboe

dm bio prison v1: add dm_cell_key_has_valid_range

2023-03-30T19:57:51+00:00

Don't have bio_detain() BUG_ON if a dm_cell_key is beyond BIO_PRISON_MAX_RANGE or spans a boundary. Update dm-thin.c:build_key() to use dm_cell_key_has_valid_range() which will do this checking without using BUG_ON. Also update process_discard_bio() to check the discard bio that DM core passes in (having first imposed max_discard_granularity based splitting). dm_cell_key_has_valid_range() will merely WARN_ON_ONCE if it returns false because if it does: it is programmer error that should be caught with proper testing. So relax the BUG_ONs to be WARN_ON_ONCE. Signed-off-by: Mike Snitzer