linux/drivers/md/dm-writecache.c, branch v5.15

dm: update target status functions to support IMA measurement

2021-08-10T17:34:23Z

For device mapper targets to take advantage of IMA's measurement capabilities, the status functions for the individual targets need to be updated to handle the status_type_t case for value STATUSTYPE_IMA. Update status functions for the following target types, to log their respective attributes to be measured using IMA. 01. cache 02. crypt 03. integrity 04. linear 05. mirror 06. multipath 07. raid 08. snapshot 09. striped 10. verity For rest of the targets, handle the STATUSTYPE_IMA case by setting the measurement buffer to NULL. For IMA to measure the data on a given system, the IMA policy on the system needs to be updated to have the following line, and the system needs to be restarted for the measurements to take effect. /etc/ima/ima-policy measure func=CRITICAL_DATA label=device-mapper template=ima-buf The measurements will be reflected in the IMA logs, which are located at: /sys/kernel/security/integrity/ima/ascii_runtime_measurements /sys/kernel/security/integrity/ima/binary_runtime_measurements These IMA logs can later be consumed by various attestation clients running on the system, and send them to external services for attesting the system. The DM target data measured by IMA subsystem can alternatively be queried from userspace by setting DM_IMA_MEASUREMENT_FLAG with DM_TABLE_STATUS_CMD. Signed-off-by: Tushar Sugandhi Signed-off-by: Mike Snitzer

dm writecache: add event counters

2021-08-10T17:27:49Z

Add 10 counters for various events (hit, miss, etc) and export them in the status line (accessed from userspace with "dmsetup status"). Also add a message "clear_stats" that resets these counters. Signed-off-by: Mikulas Patocka Signed-off-by: Mike Snitzer

dm writecache: report invalid return from writecache_map helpers

2021-08-10T17:27:48Z

If some "writecache_map_*" function returns invalid state, it is a bug. So, we should report it and not fail silently. Signed-off-by: Mikulas Patocka Signed-off-by: Mike Snitzer

dm writecache: further writecache_map() cleanup

2021-08-10T17:27:48Z

Factor out writecache_map_flush() and writecache_map_discard() from writecache_map(). Also eliminate the various goto labels in writecache_map(). Signed-off-by: Mike Snitzer

dm writecache: factor out writecache_map_remap_origin()

2021-08-10T17:27:48Z

Signed-off-by: Mike Snitzer

dm writecache: split up writecache_map() to improve code readability

2021-08-10T17:27:48Z

writecache_map() has grown too large and can be confusing to read given all the goto statements. Signed-off-by: Mike Snitzer

dm-writecache: use bvec_kmap_local instead of bvec_kmap_irq

2021-08-02T19:37:27Z

There is no need to disable interrupts in bio_copy_block, and the local only mappings helps to avoid any sort of problems with stray writes into the bio data. Signed-off-by: Christoph Hellwig Reviewed-by: Martin K. Petersen Reviewed-by: Ira Weiny Link: https://lore.kernel.org/r/20210727055646.118787-8-hch@lst.de Signed-off-by: Jens Axboe

dm writecache: make writeback pause configurable

2021-06-28T20:30:13Z

Commit 95b88f4d71cb953e02206be3c757083601391a0f ("dm writecache: pause writeback if cache full and origin being written directly") introduced a code that pauses cache flushing if we are issuing writes directly to the origin. Improve that initial commit by making the timeout code configurable (via the option "pause_writeback"). Also change the default from 1s to 3s because it performed better. Signed-off-by: Mikulas Patocka Signed-off-by: Mike Snitzer

dm writecache: pause writeback if cache full and origin being written directly

2021-06-25T20:04:01Z

Implementation reuses dm_io_tracker, that until now was only used by dm-cache, to track if any writes were issued directly to the origin (due to cache being full) within the last second. If so writeback is paused for a second. This change improves performance for when the cache is full and IO is issued directly to the origin device (rather than through the cache). Depends-on: d53f1fafec9d ("dm writecache: do direct write if the cache is full") Suggested-by: Joe Thornber Signed-off-by: Mikulas Patocka Signed-off-by: Mike Snitzer

dm writecache: add optional "metadata_only" parameter

2021-06-25T19:25:21Z

Add a "metadata_only" parameter that when present: only metadata is promoted to the cache. This option improves performance for heavier REQ_META workloads (e.g. device-mapper-test-suite's "git clone and checkout" benchmark improves from 341s to 312s). Signed-off-by: Mikulas Patocka Signed-off-by: Mike Snitzer