linux/drivers/md
Heinz Mauelshagen 63c32ed4af dm raid: add raid4/5/6 journaling support
Add md raid4/5/6 journaling support (upstream commit bac624f3f8 started
the implementation) which closes the write hole (i.e. non-atomic updates
to stripes) using a dedicated journal device.

Background:
raid4/5/6 stripes hold N data payloads per stripe plus one parity raid4/5
or two raid6 P/Q syndrome payloads in an in-memory stripe cache.
Parity or P/Q syndromes used to recover any data payloads in case of a disk
failure are calculated from the N data payloads and need to be updated on the
different component devices of the raid device.  Those are non-atomic,
persistent updates.  Hence a crash can cause failure to update all stripe
payloads persistently and thus cause data loss during stripe recovery.
This problem gets addressed by writing whole stripe cache entries (together with
journal metadata) to a persistent journal entry on a dedicated journal device.
Only if that journal entry is written successfully, the stripe cache entry is
updated on the component devices of the raid device (i.e. writethrough type).
In case of a crash, the entry can be recovered from the journal and be written
again thus ensuring consistent stripe payload suitable to data recovery.

Future dependencies:
once writeback caching being worked on to compensate for the throughput
implictions involved with writethrough overhead is supported with journaling
in upstream, an additional patch based on this one will support it in dm-raid.

Journal resilience related remarks:
because stripes are recovered from the journal in case of a crash, the
journal device better be resilient.  Resilience becomes mandatory with
future writeback support, because loosing the working set in the log
means data loss as oposed to writethrough, were the loss of the
journal device 'only' reintroduces the write hole.

Fix comment on data offsets in parse_dev_params() and initialize
new_data_offset as well.

Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2017-01-25 12:49:06 +01:00
..
bcache bcache: partition support: add 16 minors per bcacheN device 2016-12-17 13:02:00 -07:00
persistent-data dm space map: always set ev if sm_ll_mutate() succeeds 2016-12-08 14:13:15 -05:00
bitmap.c md: separate flags for superblock changes 2016-12-08 22:01:47 -08:00
bitmap.h md-cluster: sync bitmap when node received RESYNCING msg 2016-05-04 12:39:35 -07:00
dm-bio-prison.c block: add a bi_error field to struct bio 2015-07-29 08:55:15 -06:00
dm-bio-prison.h dm bio prison: add dm_cell_promote_or_release() 2015-05-29 14:19:06 -04:00
dm-bio-record.h
dm-bufio.c . various fixes and improvements to request-based DM and DM multipath 2016-12-14 11:01:00 -08:00
dm-bufio.h
dm-builtin.c dm: move request-based code out to dm-rq.[hc] 2016-06-10 15:15:44 -04:00
dm-cache-block-types.h linux: drop __bitwise__ everywhere 2016-12-16 00:13:41 +02:00
dm-cache-metadata.c dm cache metadata: remove an extra newline in DMERR and code 2016-11-21 09:52:02 -05:00
dm-cache-metadata.h dm cache: make sure every metadata function checks fail_io 2016-03-10 17:12:12 -05:00
dm-cache-policy-cleaner.c dm cache: speed up writing of the hint array 2016-09-22 11:15:02 -04:00
dm-cache-policy-internal.h dm cache: speed up writing of the hint array 2016-09-22 11:15:02 -04:00
dm-cache-policy-smq.c dm cache policy smq: use hash_32() instead of hash_32_generic() 2016-12-08 19:42:37 -05:00
dm-cache-policy.c
dm-cache-policy.h dm cache: speed up writing of the hint array 2016-09-22 11:15:02 -04:00
dm-cache-target.c dm cache: add missing cache device name to DMERR in set_cache_mode() 2016-11-21 09:52:03 -05:00
dm-core.h dm: move request-based code out to dm-rq.[hc] 2016-06-10 15:15:44 -04:00
dm-crypt.c . various fixes and improvements to request-based DM and DM multipath 2016-12-14 11:01:00 -08:00
dm-delay.c dm: rename target's per_bio_data_size to per_io_data_size 2016-02-22 22:34:37 -05:00
dm-era-target.c block: rename bio bi_rw to bi_opf 2016-08-07 14:41:02 -06:00
dm-exception-store.c - Revert a dm-multipath change that caused a regression for unprivledged 2015-11-04 21:19:53 -08:00
dm-exception-store.h dm snapshot: fix hung bios when copy error occurs 2016-01-08 20:03:05 -05:00
dm-flakey.c dm flakey: introduce "error_writes" feature 2016-12-13 15:01:31 -05:00
dm-io.c dm io: use bvec iterator helpers to implement .get_page and .next_page 2016-11-21 09:51:57 -05:00
dm-ioctl.c Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
dm-kcopyd.c dm: move request-based code out to dm-rq.[hc] 2016-06-10 15:15:44 -04:00
dm-linear.c libnvdimm for 4.8 2016-07-28 17:38:16 -07:00
dm-log-userspace-base.c dm: drop NULL test before kmem_cache_destroy() and mempool_destroy() 2015-10-31 19:06:00 -04:00
dm-log-userspace-transfer.c dm log userspace transfer: match wait_for_completion_timeout return type 2015-04-15 12:10:20 -04:00
dm-log-userspace-transfer.h
dm-log-writes.c Merge branch 'for-4.9/block' of git://git.kernel.dk/linux-block 2016-10-07 14:42:05 -07:00
dm-log.c block,fs: use REQ_* flags directly 2016-11-01 09:43:26 -06:00
dm-mpath.c dm mpath: use hw_handler_params if attached hw_handler is same as requested 2016-12-08 14:13:10 -05:00
dm-mpath.h
dm-path-selector.c
dm-path-selector.h dm path selector: remove 'repeat_count' return from .select_path hook 2016-02-22 22:34:42 -05:00
dm-queue-length.c dm path selector: remove 'repeat_count' return from .select_path hook 2016-02-22 22:34:42 -05:00
dm-raid1.c Merge branch 'for-4.10/block' of git://git.kernel.dk/linux-block 2016-12-13 10:19:16 -08:00
dm-raid.c dm raid: add raid4/5/6 journaling support 2017-01-25 12:49:06 +01:00
dm-region-hash.c block: rename bio bi_rw to bi_opf 2016-08-07 14:41:02 -06:00
dm-round-robin.c dm round robin: do not use this_cpu_ptr() without having preemption disabled 2016-08-15 09:23:14 -04:00
dm-rq.c . various fixes and improvements to request-based DM and DM multipath 2016-12-14 11:01:00 -08:00
dm-rq.h dm rq: introduce dm_mq_kick_requeue_list() 2016-09-15 11:16:05 -04:00
dm-service-time.c dm path selector: remove 'repeat_count' return from .select_path hook 2016-02-22 22:34:42 -05:00
dm-snap-persistent.c block,fs: use REQ_* flags directly 2016-11-01 09:43:26 -06:00
dm-snap-transient.c dm snapshot: fix hung bios when copy error occurs 2016-01-08 20:03:05 -05:00
dm-snap.c block: rename bio bi_rw to bi_opf 2016-08-07 14:41:02 -06:00
dm-stats.c dm: move request-based code out to dm-rq.[hc] 2016-06-10 15:15:44 -04:00
dm-stats.h dm stats: support precise timestamps 2015-06-17 12:40:40 -04:00
dm-stripe.c block: rename bio bi_rw to bi_opf 2016-08-07 14:41:02 -06:00
dm-switch.c dm switch: simplify conditional in alloc_region_table() 2015-10-31 19:06:06 -04:00
dm-sysfs.c dm: move request-based code out to dm-rq.[hc] 2016-06-10 15:15:44 -04:00
dm-table.c dm table: simplify dm_table_determine_type() 2016-12-08 14:13:03 -05:00
dm-target.c libnvdimm for 4.8 2016-07-28 17:38:16 -07:00
dm-thin-metadata.c dm thin: fix a race condition between discarding and provisioning a block 2016-07-20 12:43:35 -04:00
dm-thin-metadata.h dm thin: fix a race condition between discarding and provisioning a block 2016-07-20 12:43:35 -04:00
dm-thin.c block: rename bio bi_rw to bi_opf 2016-08-07 14:41:02 -06:00
dm-uevent.c
dm-uevent.h
dm-verity-fec.c dm verity fec: fix block calculation 2016-07-01 23:29:08 -04:00
dm-verity-fec.h dm verity: add support for forward error correction 2015-12-10 10:39:03 -05:00
dm-verity-target.c dm verity: fix incorrect error message 2016-11-21 09:52:01 -05:00
dm-verity.h dm verity: add ignore_zero_blocks feature 2015-12-10 10:39:03 -05:00
dm-zero.c block: rename bio bi_rw to bi_opf 2016-08-07 14:41:02 -06:00
dm.c . various fixes and improvements to request-based DM and DM multipath 2016-12-14 11:01:00 -08:00
dm.h dm: add infrastructure for DAX support 2016-07-20 23:49:49 -04:00
faulty.c MD: rename some functions 2016-01-20 13:52:20 -08:00
Kconfig dm block manager: make block locking optional 2016-11-14 15:17:47 -05:00
linear.c md: add block tracing for bio_remapping 2016-11-18 09:32:50 -08:00
linear.h
Makefile dm: move request-based code out to dm-rq.[hc] 2016-06-10 15:15:44 -04:00
md-cluster.c md-cluster: make resync lock also could be interruptted 2016-09-21 09:09:44 -07:00
md-cluster.h md-cluster: gather resync infos and enable recv_thread after bitmap is ready 2016-05-09 09:24:03 -07:00
md.c Merge branch 'md-next' into md-linus 2016-12-13 12:40:15 -08:00
md.h md: cleanup mddev flag clear for takeover 2017-01-05 11:45:18 -08:00
multipath.c Merge branch 'md-next' into md-linus 2016-12-13 12:40:15 -08:00
multipath.h
raid0.c md: cleanup mddev flag clear for takeover 2017-01-05 11:45:18 -08:00
raid0.h block: kill merge_bvec_fn() completely 2015-08-13 12:31:57 -06:00
raid1.c md: cleanup mddev flag clear for takeover 2017-01-05 11:45:18 -08:00
raid1.h md/raid1: add failfast handling for reads. 2016-11-22 09:13:18 -08:00
raid5-cache.c md/r5cache: fix spelling mistake on "recoverying" 2017-01-05 11:44:39 -08:00
raid5.c md/raid5: Use correct IS_ERR() variation on pointer check 2017-01-09 13:58:10 -08:00
raid5.h md/r5cache: handle alloc_page failure 2016-11-27 21:35:38 -08:00
raid10.c md/raid10: Refactor raid10_make_request 2017-01-03 08:56:52 -08:00
raid10.h md/raid10: add failfast handling for reads. 2016-11-22 09:14:28 -08:00