kernel/linux.git/include/linux/dm-bufio.h, branch v6.12.80

dm bufio: Support IO priority

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

Some IO will dispatch from kworker with different io_context settings than the submitting task, we may need to specify a priority to avoid losing priority. Add dm_bufio_read_with_ioprio() and dm_bufio_prefetch_with_ioprio() for use by bufio users to pass an ioprio other than IOPRIO_DEFAULT. Co-developed-by: Yibin Ding Signed-off-by: Yibin Ding Signed-off-by: Hongyu Jin Reviewed-by: Eric Biggers Reviewed-by: Mikulas Patocka [snitzer: introduced _with_ioprio() wrappers to reduce churn] Signed-off-by: Mike Snitzer

dm thin metadata: Fix ABBA deadlock by resetting dm_bufio_client

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

As described in commit 8111964f1b85 ("dm thin: Fix ABBA deadlock between shrink_slab and dm_pool_abort_metadata"), ABBA deadlocks will be triggered because shrinker_rwsem currently needs to held by dm_pool_abort_metadata() as a side-effect of thin-pool metadata operation failure. The following three problem scenarios have been noticed: 1) Described by commit 8111964f1b85 ("dm thin: Fix ABBA deadlock between shrink_slab and dm_pool_abort_metadata") 2) shrinker_rwsem and throttle->lock P1(drop cache) P2(kworker) drop_caches_sysctl_handler drop_slab shrink_slab down_read(&shrinker_rwsem) - LOCK A do_shrink_slab super_cache_scan prune_icache_sb dispose_list evict ext4_evict_inode ext4_clear_inode ext4_discard_preallocations ext4_mb_load_buddy_gfp ext4_mb_init_cache ext4_wait_block_bitmap __ext4_error ext4_handle_error ext4_commit_super ... dm_submit_bio do_worker throttle_work_update down_write(&t->lock) -- LOCK B process_deferred_bios commit metadata_operation_failed dm_pool_abort_metadata dm_block_manager_create dm_bufio_client_create register_shrinker down_write(&shrinker_rwsem) -- LOCK A thin_map thin_bio_map thin_defer_bio_with_throttle throttle_lock down_read(&t->lock) - LOCK B 3) shrinker_rwsem and wait_on_buffer P1(drop cache) P2(kworker) drop_caches_sysctl_handler drop_slab shrink_slab down_read(&shrinker_rwsem) - LOCK A do_shrink_slab ... ext4_wait_block_bitmap __ext4_error ext4_handle_error jbd2_journal_abort jbd2_journal_update_sb_errno jbd2_write_superblock submit_bh // LOCK B // RELEASE B do_worker throttle_work_update down_write(&t->lock) - LOCK B process_deferred_bios process_bio commit metadata_operation_failed dm_pool_abort_metadata dm_block_manager_create dm_bufio_client_create register_shrinker register_shrinker_prepared down_write(&shrinker_rwsem) - LOCK A bio_endio wait_on_buffer __wait_on_buffer Fix these by resetting dm_bufio_client without holding shrinker_rwsem. Fixes: 8111964f1b85 ("dm thin: Fix ABBA deadlock between shrink_slab and dm_pool_abort_metadata") Cc: stable@vger.kernel.org Signed-off-by: Li Lingfeng Signed-off-by: Mike Snitzer

dm bufio: remove unused dm_bufio_release_move interface

2023-03-30T19:57:50+00:00

Was used by multi-snapshot DM target that never went upstream. Signed-off-by: Joe Thornber Acked-by: Mikulas Patocka Signed-off-by: Mike Snitzer

dm: change "unsigned" to "unsigned int"

2023-02-14T19:23:06+00:00

Signed-off-by: Heinz Mauelshagen Signed-off-by: Mike Snitzer

dm: add missing SPDX-License-Indentifiers

2023-02-14T19:23:06+00:00

'GPL-2.0-only' is used instead of 'GPL-2.0' because SPDX has deprecated its use. Suggested-by: John Wiele Signed-off-by: Heinz Mauelshagen Signed-off-by: Mike Snitzer

dm bufio: Add DM_BUFIO_CLIENT_NO_SLEEP flag

2022-07-28T21:46:14+00:00

Add an optional flag that ensures dm_bufio_client does not sleep (primary focus is to service dm_bufio_get without sleeping). This allows the dm-bufio cache to be queried from interrupt context. To ensure that dm-bufio does not sleep, dm-bufio must use a spinlock instead of a mutex. Additionally, to avoid deadlocks, special care must be taken so that dm-bufio does not sleep while holding the spinlock. But again: the scope of this no_sleep is initially confined to dm_bufio_get, so __alloc_buffer_wait_no_callback is _not_ changed to avoid sleeping because __bufio_new avoids allocation for NF_GET. Signed-off-by: Nathan Huckleberry Signed-off-by: Mike Snitzer

dm bufio: Add flags argument to dm_bufio_client_create

2022-07-28T21:46:14+00:00

Add a flags argument to dm_bufio_client_create and update all the callers. This is in preparation to add the DM_BUFIO_NO_SLEEP flag. Signed-off-by: Nathan Huckleberry Signed-off-by: Mike Snitzer

dm integrity: fix flush with external metadata device

2021-01-08T20:57:29+00:00

With external metadata device, flush requests are not passed down to the data device. Fix this by submitting the flush request in dm_integrity_flush_buffers. In order to not degrade performance, we overlap the data device flush with the metadata device flush. Reported-by: Lukas Straub Signed-off-by: Mikulas Patocka Cc: stable@vger.kernel.org Signed-off-by: Mike Snitzer

dm bufio: introduce forget_buffer_locked

2020-06-05T18:59:41+00:00

Introduce a function forget_buffer_locked that forgets a range of buffers. It is more efficient than calling forget_buffer in a loop. Signed-off-by: Mikulas Patocka Signed-off-by: Mike Snitzer

dm bufio: delete unused and inefficient dm_bufio_discard_buffers

2020-06-05T00:57:38+00:00

There is no user for this interface. If in future it is needed it can be reimplemented to walk the rbtree of buffers instead of doing block-by-block lookups. Signed-off-by: Mikulas Patocka Signed-off-by: Mike Snitzer