linux/drivers/md
Andy Grover 63c8ecb626 dm thin: include metadata_low_watermark threshold in pool status
The metadata low watermark threshold is set by the kernel.  But the
kernel depends on userspace to extend the thinpool metadata device when
the threshold is crossed.

Since the metadata low watermark threshold is not visible to userspace,
upon receiving an event, userspace cannot tell that the kernel wants the
metadata device extended, instead of some other eventing condition.
Making it visible (but not settable) enables userspace to affirmatively
know the kernel is asking for a metadata device extension, by comparing
metadata_low_watermark against nr_free_blocks_metadata, also reported in
status.

Current solutions like dmeventd have their own thresholds for extending
the data and metadata devices, and both devices are checked against
their thresholds on each event.  This lessens the value of the kernel-set
threshold, since userspace will either extend the metadata device sooner,
when receiving another event; or will receive the metadata lowater event
and do nothing, if dmeventd's threshold is less than the kernel's.
(This second case is dangerous. The metadata lowater event will not be
re-sent, so no further event will be generated before the metadata
device is out if space, unless some other event causes userspace to
recheck its thresholds.)

Signed-off-by: Andy Grover <agrover@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2018-07-30 11:49:08 -04:00
..
bcache docs: Fix some broken references 2018-06-15 18:10:01 -03:00
persistent-data dm bufio: move dm-bufio.h to include/linux/ 2018-04-03 15:04:23 -04:00
dm-bio-prison-v1.c dm: adjust structure members to improve alignment 2018-06-08 11:53:14 -04:00
dm-bio-prison-v1.h block: switch bios to blk_status_t 2017-06-09 09:27:32 -06:00
dm-bio-prison-v2.c dm: adjust structure members to improve alignment 2018-06-08 11:53:14 -04:00
dm-bio-prison-v2.h
dm-bio-record.h block: replace bi_bdev with a gendisk pointer and partitions index 2017-08-23 12:49:55 -06:00
dm-bufio.c dm bufio: fix buffer alignment 2018-04-30 11:51:39 -04:00
dm-builtin.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
dm-cache-background-tracker.c dm cache background tracker: fix sparse warning 2018-04-30 15:40:40 -04:00
dm-cache-background-tracker.h
dm-cache-block-types.h
dm-cache-metadata.c dm cache: convert dm_cache_metadata.ref_count from atomic_t to refcount_t 2017-10-24 15:09:51 -04:00
dm-cache-metadata.h
dm-cache-policy-internal.h
dm-cache-policy-smq.c treewide: Use array_size() in vzalloc() 2018-06-12 16:19:22 -07:00
dm-cache-policy.c
dm-cache-policy.h
dm-cache-target.c dm cache: only allow a single io_mode cache feature to be requested 2018-07-27 15:24:18 -04:00
dm-core.h dm: adjust structure members to improve alignment 2018-06-08 11:53:14 -04:00
dm-crypt.c dm crypt: convert essiv from ahash to shash 2018-07-27 15:24:28 -04:00
dm-delay.c dm delay: add flush as a third class of IO 2018-07-27 15:24:19 -04:00
dm-era-target.c dm: allow targets to return output from messages they are sent 2018-04-03 15:04:10 -04:00
dm-exception-store.c
dm-exception-store.h
dm-flakey.c dm: remove fmode_t argument from .prepare_ioctl hook 2018-04-04 12:12:39 -04:00
dm-integrity.c dm integrity: recalculate checksums on creation 2018-07-27 15:24:27 -04:00
dm-io.c dm: Use kzalloc for all structs with embedded biosets/mempools 2018-06-05 08:47:43 -06:00
dm-ioctl.c dm: report which conflicting type caused error during table_load() 2018-06-08 09:50:15 -04:00
dm-kcopyd.c dm: adjust structure members to improve alignment 2018-06-08 11:53:14 -04:00
dm-linear.c dax: Introduce a ->copy_to_iter dax operation 2018-05-22 23:18:31 -07:00
dm-log-userspace-base.c dm: convert to bioset_init()/mempool_init() 2018-05-30 15:33:32 -06:00
dm-log-userspace-transfer.c
dm-log-userspace-transfer.h
dm-log-writes.c dax: Introduce a ->copy_to_iter dax operation 2018-05-22 23:18:31 -07:00
dm-log.c
dm-mpath.c block: sanitize blk_get_request calling conventions 2018-05-14 08:55:12 -06:00
dm-mpath.h
dm-path-selector.c
dm-path-selector.h
dm-queue-length.c dm mpath selector: more evenly distribute ties 2018-01-29 13:44:58 -05:00
dm-raid1.c dm mirror: remove VLA usage 2018-05-04 10:35:20 -04:00
dm-raid.c dm raid: don't use 'const' in function return 2018-06-22 14:51:12 -04:00
dm-region-hash.c - Error path bug fix for overflow tests (Dan) 2018-06-12 18:28:00 -07:00
dm-round-robin.c
dm-rq.c dm: convert to bioset_init()/mempool_init() 2018-05-30 15:33:32 -06:00
dm-rq.h dm rq: do not update rq partially in each ending bio 2017-08-28 10:23:28 -04:00
dm-service-time.c dm mpath selector: more evenly distribute ties 2018-01-29 13:44:58 -05:00
dm-snap-persistent.c dm bufio: move dm-bufio.h to include/linux/ 2018-04-03 15:04:23 -04:00
dm-snap-transient.c
dm-snap.c treewide: kmalloc() -> kmalloc_array() 2018-06-12 16:19:22 -07:00
dm-stats.c treewide: kmalloc() -> kmalloc_array() 2018-06-12 16:19:22 -07:00
dm-stats.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
dm-stripe.c dax: Introduce a ->copy_to_iter dax operation 2018-05-22 23:18:31 -07:00
dm-switch.c treewide: Use array_size() in vmalloc() 2018-06-12 16:19:22 -07:00
dm-sysfs.c
dm-table.c dm: prevent DAX mounts if not supported 2018-06-28 16:06:14 -04:00
dm-target.c dm: remove unused macro DM_MOD_NAME_SIZE 2018-04-03 15:04:15 -04:00
dm-thin-metadata.c dm thin metadata: remove needless work from __commit_transaction 2018-06-22 14:51:11 -04:00
dm-thin-metadata.h
dm-thin.c dm thin: include metadata_low_watermark threshold in pool status 2018-07-30 11:49:08 -04:00
dm-uevent.c
dm-uevent.h
dm-unstripe.c dm unstripe: remove unnecessary header includes 2018-04-03 15:04:15 -04:00
dm-verity-fec.c Refactors rslib and callers to provide a per-instance allocation area 2018-06-05 10:48:05 -07:00
dm-verity-fec.h dm: convert to bioset_init()/mempool_init() 2018-05-30 15:33:32 -06:00
dm-verity-target.c treewide: kvzalloc() -> kvcalloc() 2018-06-12 16:19:22 -07:00
dm-verity.h dm verity: add 'check_at_most_once' option to only validate hashes once 2018-04-03 15:04:29 -04:00
dm-writecache.c dm writecache: report start_sector in status line 2018-07-27 15:28:58 -04:00
dm-zero.c dm: don't return errnos from ->map 2017-06-09 09:27:32 -06:00
dm-zoned-metadata.c dm: backfill missing calls to mutex_destroy() 2018-01-17 09:16:15 -05:00
dm-zoned-reclaim.c dm zoned: use GFP_NOIO in I/O path 2017-07-26 15:55:43 -04:00
dm-zoned-target.c dm zoned: avoid triggering reclaim from inside dmz_map() 2018-06-22 14:51:12 -04:00
dm-zoned.h dm zoned: drive-managed zoned block device target 2017-06-19 11:05:20 -04:00
dm.c dm: prevent DAX mounts if not supported 2018-06-28 16:06:14 -04:00
dm.h dm: move dm_table_destroy() to same header as dm_table_create() 2018-01-17 09:16:06 -05:00
Kconfig dm: add writecache target 2018-06-08 11:59:51 -04:00
Makefile dm: add writecache target 2018-06-08 11:59:51 -04:00
md-bitmap.c treewide: kzalloc() -> kcalloc() 2018-06-12 16:19:22 -07:00
md-bitmap.h Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/shli/md 2017-11-14 16:07:26 -08:00
md-cluster.c treewide: kzalloc() -> kcalloc() 2018-06-12 16:19:22 -07:00
md-cluster.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
md-faulty.c md: convert to bioset_init()/mempool_init() 2018-05-30 15:33:32 -06:00
md-linear.c md: convert to bioset_init()/mempool_init() 2018-05-30 15:33:32 -06:00
md-linear.h Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/shli/md 2017-11-14 16:07:26 -08:00
md-multipath.c treewide: kzalloc() -> kcalloc() 2018-06-12 16:19:22 -07:00
md-multipath.h md: convert to bioset_init()/mempool_init() 2018-05-30 15:33:32 -06:00
md.c MD: cleanup resources in failure 2018-06-18 09:46:13 -07:00
md.h Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/shli/md 2018-06-09 12:01:36 -07:00
raid0.c treewide: kzalloc() -> kcalloc() 2018-06-12 16:19:22 -07:00
raid0.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
raid1-10.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
raid1.c treewide: kzalloc() -> kcalloc() 2018-06-12 16:19:22 -07:00
raid1.h md: convert to bioset_init()/mempool_init() 2018-05-30 15:33:32 -06:00
raid5-cache.c md: convert to bioset_init()/mempool_init() 2018-05-30 15:33:32 -06:00
raid5-log.h raid5-ppl: fix handling flush requests 2018-02-21 09:40:40 -08:00
raid5-ppl.c md: convert to bioset_init()/mempool_init() 2018-05-30 15:33:32 -06:00
raid5.c treewide: kzalloc() -> kcalloc() 2018-06-12 16:19:22 -07:00
raid5.h Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/shli/md 2018-06-09 12:01:36 -07:00
raid10.c md/raid10: fix that replacement cannot complete recovery after reassemble 2018-06-28 13:04:49 -07:00
raid10.h md: convert to bioset_init()/mempool_init() 2018-05-30 15:33:32 -06:00