user/sven/linux.git/drivers/md/Kconfig, branch v4.9.2

dm: add missing newline between DM_DEBUG_BLOCK_STACK_TRACING and DM_BUFIO

2016-03-10T22:12:11Z

Signed-off-by: Mike Snitzer

dm cache: make the 'mq' policy an alias for 'smq'

2016-03-10T22:12:08Z

smq seems to be performing better than the old mq policy in all situations, as well as using a quarter of the memory. Make 'mq' an alias for 'smq' when choosing a cache policy. The tunables that were present for the old mq are faked, and have no effect. mq should be considered deprecated now. Signed-off-by: Joe Thornber Signed-off-by: Mike Snitzer

dm verity: add support for forward error correction

2015-12-10T15:39:03Z

Add support for correcting corrupted blocks using Reed-Solomon. This code uses RS(255, N) interleaved across data and hash blocks. Each error-correcting block covers N bytes evenly distributed across the combined total data, so that each byte is a maximum distance away from the others. This makes it possible to recover from several consecutive corrupted blocks with relatively small space overhead. In addition, using verity hashes to locate erasures nearly doubles the effectiveness of error correction. Being able to detect corrupted blocks also improves performance, because only corrupted blocks need to corrected. For a 2 GiB partition, RS(255, 253) (two parity bytes for each 253-byte block) can correct up to 16 MiB of consecutive corrupted blocks if erasures can be located, and 8 MiB if they cannot, with 16 MiB space overhead. Signed-off-by: Sami Tolvanen Signed-off-by: Mike Snitzer

dm bufio: store stacktrace in buffers to help find buffer leaks

2015-12-10T15:38:58Z

The option DM_DEBUG_BLOCK_STACK_TRACING is moved from persistent-data directory to device mapper directory because it will now be used by persistent-data and bufio. When the option is enabled, each bufio buffer stores the stacktrace of the last dm_bufio_get(), dm_bufio_read() or dm_bufio_new() call that increased the hold count to 1. The buffer's stacktrace is printed if the buffer was not released before the bufio client is destroyed. When DM_DEBUG_BLOCK_STACK_TRACING is enabled, any bufio buffer leaks are considered warnings - i.e. the kernel continues afterwards. If not enabled, buffer leaks are considered BUGs and the kernel with crash. Reasoning on this disposition is: if we only ever warned on buffer leaks users would generally ignore them and the problematic code would never get fixed. Successfully used to find source of bufio leaks fixed with commit fce079f63c3 ("dm btree: fix bufio buffer leaks in dm_btree_del() error path"). Signed-off-by: Mikulas Patocka Signed-off-by: Mike Snitzer

raid5-cache: add crc32c Kconfig dependency

2015-11-08T22:09:52Z

The recent change of the raid5-cache code to use crc32c instead of crc32 causes link errors when CONFIG_LIBCRC32C is disabled: drivers/built-in.o: In function crc32c' core.c:(.text+0x1c6060): undefined reference to `crc32c' This adds an explicit 'select' statement like all other users of this function do. Signed-off-by: Arnd Bergmann Fixes: 5cb2fbd6ea0d ("raid5-cache: use crc32c checksum") Signed-off-by: NeilBrown

Merge tag 'scsi-misc' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi

2015-09-12T01:15:18Z

Pull second round of SCSI updates from James Bottomley: "There's one late arriving patch here (added today), fixing a build issue which the scsi_dh patch set in here uncovered. Other than that, everything has been incubated in -next and the checkers for a week. The major pieces of this patch are a set patches facilitating better integration between scsi and scsi_dh (the device handling layer used by multi-path; all the dm parts are acked by Mike Snitzer). This also includes driver updates for mp3sas, scsi_debug and an assortment of bug fixes" * tag 'scsi-misc' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi: (50 commits) scsi_dh: fix randconfig build error scsi: fix scsi_error_handler vs. scsi_host_dev_release race fcoe: Convert use of __constant_htons to htons mpt2sas: setpci reset kernel oops fix pm80xx: Don't override ts->stat on IO_OPEN_CNX_ERROR_HW_RESOURCE_BUSY lpfc: Fix possible use-after-free and double free in lpfc_mbx_cmpl_rdp_page_a2() bfa: Fix incorrect de-reference of pointer bfa: Fix indentation scsi_transport_sas: Remove check for SAS expander when querying bay/enclosure IDs. scsi_debug: resp_request: remove unused variable scsi_debug: fix REPORT LUNS Well Known LU scsi_debug: schedule_resp fix input variable check scsi_debug: make dump_sector static scsi_debug: vfree is null safe so drop the check scsi_debug: use SCSI_W_LUN_REPORT_LUNS instead of SAM2_WLUN_REPORT_LUNS; scsi_debug: define pr_fmt() for consistent logging mpt2sas: Refcount fw_events and fix unsafe list usage mpt2sas: Refcount sas_device objects and fix unsafe list usage scsi_dh: return SCSI_DH_NOTCONN in scsi_dh_activate() scsi_dh: don't allow to detach device handlers at runtime ...

scsi_dh: fix randconfig build error

2015-09-11T18:54:37Z

It looks like the Kconfig check that was meant to fix this (commit fe9233fb6914a0eb20166c967e3020f7f0fba2c9 [SCSI] scsi_dh: fix kconfig related build errors) was actually reversed, but no-one noticed until the new set of patches which separated DM and SCSI_DH). Fixes: fe9233fb6914a0eb20166c967e3020f7f0fba2c9 Signed-off-by: Christoph Hellwig Tested-by: Mike Snitzer Signed-off-by: James Bottomley

dm: Spelling s/consitent/consistent/

2015-08-07T12:36:43Z

Signed-off-by: Geert Uytterhoeven Signed-off-by: Jiri Kosina

dm crypt: update wiki page URL

2015-07-27T11:58:16Z

Cryptsetup moved to gitlab. This is a leftover from commit e44f23b32dc7 (dm crypt: update URLs to new cryptsetup project page, 2015-04-05). Signed-off-by: Baruch Siach Signed-off-by: Mike Snitzer

dm cache: add stochastic-multi-queue (smq) policy

2015-06-11T21:12:59Z

The stochastic-multi-queue (smq) policy addresses some of the problems with the current multiqueue (mq) policy. Memory usage ------------ The mq policy uses a lot of memory; 88 bytes per cache block on a 64 bit machine. SMQ uses 28bit indexes to implement it's data structures rather than pointers. It avoids storing an explicit hit count for each block. It has a 'hotspot' queue rather than a pre cache which uses a quarter of the entries (each hotspot block covers a larger area than a single cache block). All these mean smq uses ~25bytes per cache block. Still a lot of memory, but a substantial improvement nontheless. Level balancing --------------- MQ places entries in different levels of the multiqueue structures based on their hit count (~ln(hit count)). This means the bottom levels generally have the most entries, and the top ones have very few. Having unbalanced levels like this reduces the efficacy of the multiqueue. SMQ does not maintain a hit count, instead it swaps hit entries with the least recently used entry from the level above. The over all ordering being a side effect of this stochastic process. With this scheme we can decide how many entries occupy each multiqueue level, resulting in better promotion/demotion decisions. Adaptability ------------ The MQ policy maintains a hit count for each cache block. For a different block to get promoted to the cache it's hit count has to exceed the lowest currently in the cache. This means it can take a long time for the cache to adapt between varying IO patterns. Periodically degrading the hit counts could help with this, but I haven't found a nice general solution. SMQ doesn't maintain hit counts, so a lot of this problem just goes away. In addition it tracks performance of the hotspot queue, which is used to decide which blocks to promote. If the hotspot queue is performing badly then it starts moving entries more quickly between levels. This lets it adapt to new IO patterns very quickly. Performance ----------- In my tests SMQ shows substantially better performance than MQ. Once this matures a bit more I'm sure it'll become the default policy. Signed-off-by: Joe Thornber Signed-off-by: Mike Snitzer