kernel/linux.git/drivers/md/Makefile, branch linux-5.11.y

dm: rename multipath path selector source files to have "dm-ps" prefix

2020-12-04T23:04:35+00:00

Additional prefix helps clarify that these source files implement path selectors. Required updating Makefile to still build modules _without_ the "dm-ps" prefix to preserve dm-multipath's ability to autoload path selector modules. While at it, cleaned up some DM whitespace in Makefile. Signed-off-by: Mike Snitzer

dm mpath: add IO affinity path selector

2020-12-04T23:04:35+00:00

This patch adds a path selector that selects paths based on a CPU to path mapping the user passes in and what CPU we are executing on. The primary user for this PS is where the app is optimized to use specific CPUs so other PSs undo the apps handy work, and the storage and it's transport are not a bottlneck. For these io-affinity PS setups a path's transport/interconnect perf is not going to flucuate a lot and there is no major differences between paths, so QL/HST smarts do not help and RR always messes up what the app is trying to do. On a system with 16 cores, where you have a job per CPU: fio --filename=/dev/dm-0 --direct=1 --rw=randrw --bs=4k \ --ioengine=libaio --iodepth=128 --numjobs=16 and a dm-multipath device setup where each CPU is mapped to one path: // When in mq mode I had to set dm_mq_nr_hw_queues=$NUM_PATHS. // Bio mode also showed similar results. 0 16777216 multipath 0 0 1 1 io-affinity 0 16 1 8:16 1 8:32 2 8:64 4 8:48 8 8:80 10 8:96 20 8:112 40 8:128 80 8:144 100 8:160 200 8:176 400 8:192 800 8:208 1000 8:224 2000 8:240 4000 65:0 8000 we can see a IOPs increase of 25%. The percent increase depends on the device and interconnect. For a slower/medium speed path/device that can do around 180K IOPs a path if you ran that fio command to it directly we saw a 25% increase like above. Slower path'd devices that could do around 90K per path showed maybe around a 2 - 5% increase. If you use something like null_blk or scsi_debug which can multi-million IOPs and hack it up so each device they export shows up as a path then you see 50%+ increases. Signed-off-by: Mike Christie Signed-off-by: Mike Snitzer

md: move the early init autodetect code to drivers/md/

2020-07-16T13:34:47+00:00

Just like the NFS and CIFS root code this better lives with the driver it is tightly integrated with. Signed-off-by: Christoph Hellwig Acked-by: Song Liu Acked-by: Linus Torvalds

dm mpath: add Historical Service Time Path Selector

2020-05-15T14:29:36+00:00

This new selector keeps an exponential moving average of the service time for each path (losely defined as delta between start_io and end_io), and uses this along with the number of inflight requests to estimate future service time for a path. Since we don't have a prober to account for temporally slow paths, re-try "slow" paths every once in a while (num_paths * historical_service_time). To account for fast paths transitioning to slow, if a path has not completed any request within (num_paths * historical_service_time), limit the number of outstanding requests. To account for low volume situations where number of inflight IOs would be zero, the last finish time of each path is factored in. Signed-off-by: Khazhismel Kumykov Co-developed-by: Gabriel Krisman Bertazi Signed-off-by: Gabriel Krisman Bertazi Signed-off-by: Mike Snitzer

dm: add emulated block size target

2020-05-15T14:29:35+00:00

This new target is similar to the linear target except that it emulates a smaller logical block size on a device with a larger logical block size. Its main purpose is to emulate 512 byte sectors on 4K native disks (i.e. 512e). See Documentation/admin-guide/device-mapper/dm-ebs.rst for details. Reviewed-by: Damien Le Moal Signed-off-by: Heinz Mauelshagen Signed-off-by: Randy Dunlap [Kconfig fixes] Signed-off-by: Zheng Bin [static fixes] Signed-off-by: Mike Snitzer

dm: add clone target

2019-09-12T13:32:31+00:00

Add the dm-clone target, which allows cloning of arbitrary block devices. dm-clone produces a one-to-one copy of an existing, read-only source device into a writable destination device: It presents a virtual block device which makes all data appear immediately, and redirects reads and writes accordingly. The main use case of dm-clone is to clone a potentially remote, high-latency, read-only, archival-type block device into a writable, fast, primary-type device for fast, low-latency I/O. The cloned device is visible/mountable immediately and the copy of the source device to the destination device happens in the background, in parallel with user I/O. When the cloning completes, the dm-clone table can be removed altogether and be replaced, e.g., by a linear table, mapping directly to the destination device. For further information and examples of how to use dm-clone, please read Documentation/admin-guide/device-mapper/dm-clone.rst Suggested-by: Vangelis Koukis Co-developed-by: Ilias Tsitsimpis Signed-off-by: Ilias Tsitsimpis Signed-off-by: Nikos Tsironis Signed-off-by: Mike Snitzer

dm verity: add root hash pkcs#7 signature verification

2019-08-23T14:13:14+00:00

The verification is to support cases where the root hash is not secured by Trusted Boot, UEFI Secureboot or similar technologies. One of the use cases for this is for dm-verity volumes mounted after boot, the root hash provided during the creation of the dm-verity volume has to be secure and thus in-kernel validation implemented here will be used before we trust the root hash and allow the block device to be created. The signature being provided for verification must verify the root hash and must be trusted by the builtin keyring for verification to succeed. The hash is added as a key of type "user" and the description is passed to the kernel so it can look it up and use it for verification. Adds CONFIG_DM_VERITY_VERIFY_ROOTHASH_SIG which can be turned on if root hash verification is needed. Kernel commandline dm_verity module parameter 'require_signatures' will indicate whether to force root hash signature verification (for all dm verity volumes). Signed-off-by: Jaskaran Khurana Tested-and-Reviewed-by: Milan Broz Signed-off-by: Mike Snitzer

dm: add dust target

2019-04-30T20:37:19+00:00

Add the dm-dust target, which simulates the behavior of bad sectors at arbitrary locations, and the ability to enable the emulation of the read failures at an arbitrary time. This target behaves similarly to a linear target. At a given time, the user can send a message to the target to start failing read requests on specific blocks. When the failure behavior is enabled, reads of blocks configured "bad" will fail with EIO. Writes of blocks configured "bad" will result in the following: 1. Remove the block from the "bad block list". 2. Successfully complete the write. After this point, the block will successfully contain the written data, and will service reads and writes normally. This emulates the behavior of a "remapped sector" on a hard disk drive. dm-dust provides logging of which blocks have been added or removed to the "bad block list", as well as logging when a block has been removed from the bad block list. These messages can be used alongside the messages from the driver using a dm-dust device to analyze the driver's behavior when a read fails at a given time. (This logging can be reduced via a "quiet" mode, if desired.) NOTE: If the block size is larger than 512 bytes, only the first sector of each "dust block" is detected. Placing a limiting layer above a dust target, to limit the minimum I/O size to the dust block size, will ensure proper emulation of the given large block size. Signed-off-by: Bryan Gurney Co-developed-by: Joe Shimkus Co-developed-by: John Dorminy Co-developed-by: John Pittman Co-developed-by: Thomas Jaskiewicz Signed-off-by: Mike Snitzer

dm: add support to directly boot to a mapped device

2019-03-05T19:53:50+00:00

Add a "create" module parameter, which allows device-mapper targets to be configured at boot time. This enables early use of DM targets in the boot process (as the root device or otherwise) without the need of an initramfs. The syntax used in the boot param is based on the concise format from the dmsetup tool to follow the rule of least surprise: dmsetup table --concise /dev/mapper/lroot Which is: dm-mod.create=,,,,[,

+][;,,,,

+]+] Where, ::= The device name. ::= xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx | "" ::= The device minor number | "" ::= "ro" | "rw"

::= ::= "verity" | "linear" | ... For example, the following could be added in the boot parameters: dm-mod.create="lroot,,,rw, 0 4096 linear 98:16 0, 4096 4096 linear 98:32 0" root=/dev/dm-0 Only the targets that were tested are allowed and the ones that don't change any block device when the device is create as read-only. For example, mirror and cache targets are not allowed. The rationale behind this is that if the user makes a mistake, choosing the wrong device to be the mirror or the cache can corrupt data. The only targets initially allowed are: * crypt * delay * linear * snapshot-origin * striped * verity Co-developed-by: Will Drewry Co-developed-by: Kees Cook Co-developed-by: Enric Balletbo i Serra Signed-off-by: Helen Koike Reviewed-by: Kees Cook Signed-off-by: Mike Snitzer

dm: add writecache target

2018-06-08T15:59:51+00:00

The writecache target caches writes on persistent memory or SSD. It is intended for databases or other programs that need extremely low commit latency. The writecache target doesn't cache reads because reads are supposed to be cached in page cache in normal RAM. If persistent memory isn't available this target can still be used in SSD mode. Signed-off-by: Mikulas Patocka Signed-off-by: Colin Ian King # fix missing goto Signed-off-by: Ross Zwisler # fix compilation issue with !DAX Signed-off-by: Dan Carpenter # use msecs_to_jiffies Acked-by: Dan Williams # reworks to unify ARM and x86 flushing Signed-off-by: Mike Snitzer