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* dm mpath: add Historical Service Time Path SelectorKhazhismel Kumykov2020-05-151-0/+1
| | | | | | | | | | | | | | | | | | | 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 <khazhy@google.com> Co-developed-by: Gabriel Krisman Bertazi <krisman@collabora.com> Signed-off-by: Gabriel Krisman Bertazi <krisman@collabora.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
* dm: add emulated block size targetHeinz Mauelshagen2020-05-151-0/+2
| | | | | | | | | | | | | | | 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 <DamienLeMoal@wdc.com> Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com> Signed-off-by: Randy Dunlap <rdunlap@infradead.org> [Kconfig fixes] Signed-off-by: Zheng Bin <zhengbin13@huawei.com> [static fixes] Signed-off-by: Mike Snitzer <snitzer@redhat.com>
* dm: add clone targetNikos Tsironis2019-09-121-0/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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 <vkoukis@arrikto.com> Co-developed-by: Ilias Tsitsimpis <iliastsi@arrikto.com> Signed-off-by: Ilias Tsitsimpis <iliastsi@arrikto.com> Signed-off-by: Nikos Tsironis <ntsironis@arrikto.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
* dm verity: add root hash pkcs#7 signature verificationJaskaran Khurana2019-08-231-0/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | 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 <jaskarankhurana@linux.microsoft.com> Tested-and-Reviewed-by: Milan Broz <gmazyland@gmail.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
* dm: add dust targetBryan Gurney2019-04-301-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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 <bgurney@redhat.com> Co-developed-by: Joe Shimkus <jshimkus@redhat.com> Co-developed-by: John Dorminy <jdorminy@redhat.com> Co-developed-by: John Pittman <jpittman@redhat.com> Co-developed-by: Thomas Jaskiewicz <tjaskiew@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
* dm: add support to directly boot to a mapped deviceHelen Koike2019-03-051-0/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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=<name>,<uuid>,<minor>,<flags>,<table>[,<table>+][;<name>,<uuid>,<minor>,<flags>,<table>[,<table>+]+] Where, <name> ::= The device name. <uuid> ::= xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx | "" <minor> ::= The device minor number | "" <flags> ::= "ro" | "rw" <table> ::= <start_sector> <num_sectors> <target_type> <target_args> <target_type> ::= "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 <wad@chromium.org> Co-developed-by: Kees Cook <keescook@chromium.org> Co-developed-by: Enric Balletbo i Serra <enric.balletbo@collabora.com> Signed-off-by: Helen Koike <helen.koike@collabora.com> Reviewed-by: Kees Cook <keescook@chromium.org> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
* dm: add writecache targetMikulas Patocka2018-06-081-0/+1
| | | | | | | | | | | | | | | | | | | 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 <mpatocka@redhat.com> Signed-off-by: Colin Ian King <colin.king@canonical.com> # fix missing goto Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com> # fix compilation issue with !DAX Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> # use msecs_to_jiffies Acked-by: Dan Williams <dan.j.williams@intel.com> # reworks to unify ARM and x86 flushing Signed-off-by: Mike Snitzer <msnitzer@redhat.com>
* dm: add unstriped targetScott Bauer2018-01-171-0/+1
| | | | | | | | | | | | | | | | | | This device mapper "unstriped" target remaps and unstripes I/O so it is issued solely on a single drive in a HW RAID0 or dm-striped target. In a 4 drive HW RAID0 the striped target exposes 1/4th of the LBA range as a virtual drive. Each I/O to that virtual drive will only be issued to the 1 drive that was selected of the 4 drives in the HW RAID0. This unstriped target is most useful for Intel NVMe drives that have multiple cores but that do not have firmware control to pin separate LBA ranges to each discrete cpu core. Signed-off-by: Scott Bauer <scott.bauer@intel.com> Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com> Acked-by: Keith Busch <keith.busch@intel.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
* Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/shli/mdLinus Torvalds2017-11-141-1/+4
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Pull MD update from Shaohua Li: "This update mostly includes bug fixes: - md-cluster now supports raid10 from Guoqing - raid5 PPL fixes from Artur - badblock regression fix from Bo - suspend hang related fixes from Neil - raid5 reshape fixes from Neil - raid1 freeze deadlock fix from Nate - memleak fixes from Zdenek - bitmap related fixes from Me and Tao - other fixes and cleanups" * 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/shli/md: (33 commits) md: free unused memory after bitmap resize md: release allocated bitset sync_set md/bitmap: clear BITMAP_WRITE_ERROR bit before writing it to sb md: be cautious about using ->curr_resync_completed for ->recovery_offset badblocks: fix wrong return value in badblocks_set if badblocks are disabled md: don't check MD_SB_CHANGE_CLEAN in md_allow_write md-cluster: update document for raid10 md: remove redundant variable q raid1: remove obsolete code in raid1_write_request md-cluster: Use a small window for raid10 resync md-cluster: Suspend writes in RAID10 if within range md-cluster/raid10: set "do_balance = 0" if area is resyncing md: use lockdep_assert_held raid1: prevent freeze_array/wait_all_barriers deadlock md: use TASK_IDLE instead of blocking signals md: remove special meaning of ->quiesce(.., 2) md: allow metadata update while suspending. md: use mddev_suspend/resume instead of ->quiesce() md: move suspend_hi/lo handling into core md code md: don't call bitmap_create() while array is quiesced. ...
| * md: rename some drivers/md/ files to have an "md-" prefixMike Snitzer2017-10-161-1/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Motivated by the desire to illiminate the imprecise nature of DM-specific patches being unnecessarily sent to both the MD maintainer and mailing-list. Which is born out of the fact that DM files also reside in drivers/md/ Now all MD-specific files in drivers/md/ start with either "raid" or "md-" and the MAINTAINERS file has been updated accordingly. Shaohua: don't change module name Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Shaohua Li <shli@fb.com>
* | License cleanup: add SPDX GPL-2.0 license identifier to files with no licenseGreg Kroah-Hartman2017-11-021-0/+1
|/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Many source files in the tree are missing licensing information, which makes it harder for compliance tools to determine the correct license. By default all files without license information are under the default license of the kernel, which is GPL version 2. Update the files which contain no license information with the 'GPL-2.0' SPDX license identifier. The SPDX identifier is a legally binding shorthand, which can be used instead of the full boiler plate text. This patch is based on work done by Thomas Gleixner and Kate Stewart and Philippe Ombredanne. How this work was done: Patches were generated and checked against linux-4.14-rc6 for a subset of the use cases: - file had no licensing information it it. - file was a */uapi/* one with no licensing information in it, - file was a */uapi/* one with existing licensing information, Further patches will be generated in subsequent months to fix up cases where non-standard license headers were used, and references to license had to be inferred by heuristics based on keywords. The analysis to determine which SPDX License Identifier to be applied to a file was done in a spreadsheet of side by side results from of the output of two independent scanners (ScanCode & Windriver) producing SPDX tag:value files created by Philippe Ombredanne. Philippe prepared the base worksheet, and did an initial spot review of a few 1000 files. The 4.13 kernel was the starting point of the analysis with 60,537 files assessed. Kate Stewart did a file by file comparison of the scanner results in the spreadsheet to determine which SPDX license identifier(s) to be applied to the file. She confirmed any determination that was not immediately clear with lawyers working with the Linux Foundation. Criteria used to select files for SPDX license identifier tagging was: - Files considered eligible had to be source code files. - Make and config files were included as candidates if they contained >5 lines of source - File already had some variant of a license header in it (even if <5 lines). All documentation files were explicitly excluded. The following heuristics were used to determine which SPDX license identifiers to apply. - when both scanners couldn't find any license traces, file was considered to have no license information in it, and the top level COPYING file license applied. For non */uapi/* files that summary was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 11139 and resulted in the first patch in this series. If that file was a */uapi/* path one, it was "GPL-2.0 WITH Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 WITH Linux-syscall-note 930 and resulted in the second patch in this series. - if a file had some form of licensing information in it, and was one of the */uapi/* ones, it was denoted with the Linux-syscall-note if any GPL family license was found in the file or had no licensing in it (per prior point). Results summary: SPDX license identifier # files ---------------------------------------------------|------ GPL-2.0 WITH Linux-syscall-note 270 GPL-2.0+ WITH Linux-syscall-note 169 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17 LGPL-2.1+ WITH Linux-syscall-note 15 GPL-1.0+ WITH Linux-syscall-note 14 ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5 LGPL-2.0+ WITH Linux-syscall-note 4 LGPL-2.1 WITH Linux-syscall-note 3 ((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3 ((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1 and that resulted in the third patch in this series. - when the two scanners agreed on the detected license(s), that became the concluded license(s). - when there was disagreement between the two scanners (one detected a license but the other didn't, or they both detected different licenses) a manual inspection of the file occurred. - In most cases a manual inspection of the information in the file resulted in a clear resolution of the license that should apply (and which scanner probably needed to revisit its heuristics). - When it was not immediately clear, the license identifier was confirmed with lawyers working with the Linux Foundation. - If there was any question as to the appropriate license identifier, the file was flagged for further research and to be revisited later in time. In total, over 70 hours of logged manual review was done on the spreadsheet to determine the SPDX license identifiers to apply to the source files by Kate, Philippe, Thomas and, in some cases, confirmation by lawyers working with the Linux Foundation. Kate also obtained a third independent scan of the 4.13 code base from FOSSology, and compared selected files where the other two scanners disagreed against that SPDX file, to see if there was new insights. The Windriver scanner is based on an older version of FOSSology in part, so they are related. Thomas did random spot checks in about 500 files from the spreadsheets for the uapi headers and agreed with SPDX license identifier in the files he inspected. For the non-uapi files Thomas did random spot checks in about 15000 files. In initial set of patches against 4.14-rc6, 3 files were found to have copy/paste license identifier errors, and have been fixed to reflect the correct identifier. Additionally Philippe spent 10 hours this week doing a detailed manual inspection and review of the 12,461 patched files from the initial patch version early this week with: - a full scancode scan run, collecting the matched texts, detected license ids and scores - reviewing anything where there was a license detected (about 500+ files) to ensure that the applied SPDX license was correct - reviewing anything where there was no detection but the patch license was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied SPDX license was correct This produced a worksheet with 20 files needing minor correction. This worksheet was then exported into 3 different .csv files for the different types of files to be modified. These .csv files were then reviewed by Greg. Thomas wrote a script to parse the csv files and add the proper SPDX tag to the file, in the format that the file expected. This script was further refined by Greg based on the output to detect more types of files automatically and to distinguish between header and source .c files (which need different comment types.) Finally Greg ran the script using the .csv files to generate the patches. Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org> Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* dm zoned: drive-managed zoned block device targetDamien Le Moal2017-06-191-0/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The dm-zoned device mapper target provides transparent write access to zoned block devices (ZBC and ZAC compliant block devices). dm-zoned hides to the device user (a file system or an application doing raw block device accesses) any constraint imposed on write requests by the device, equivalent to a drive-managed zoned block device model. Write requests are processed using a combination of on-disk buffering using the device conventional zones and direct in-place processing for requests aligned to a zone sequential write pointer position. A background reclaim process implemented using dm_kcopyd_copy ensures that conventional zones are always available for executing unaligned write requests. The reclaim process overhead is minimized by managing buffer zones in a least-recently-written order and first targeting the oldest buffer zones. Doing so, blocks under regular write access (such as metadata blocks of a file system) remain stored in conventional zones, resulting in no apparent overhead. dm-zoned implementation focus on simplicity and on minimizing overhead (CPU, memory and storage overhead). For a 14TB host-managed disk with 256 MB zones, dm-zoned memory usage per disk instance is at most about 3 MB and as little as 5 zones will be used internally for storing metadata and performing buffer zone reclaim operations. This is achieved using zone level indirection rather than a full block indirection system for managing block movement between zones. dm-zoned primary target is host-managed zoned block devices but it can also be used with host-aware device models to mitigate potential device-side performance degradation due to excessive random writing. Zoned block devices can be formatted and checked for use with the dm-zoned target using the dmzadm utility available at: https://github.com/hgst/dm-zoned-tools Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com> Reviewed-by: Hannes Reinecke <hare@suse.com> Reviewed-by: Bart Van Assche <bart.vanassche@sandisk.com> [Mike Snitzer partly refactored Damien's original work to cleanup the code] Signed-off-by: Mike Snitzer <snitzer@redhat.com>
* Merge tag 'for-4.12/dm-changes' of ↵Linus Torvalds2017-05-031-3/+4
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm Pull device mapper updates from Mike Snitzer: - A major update for DM cache that reduces the latency for deciding whether blocks should migrate to/from the cache. The bio-prison-v2 interface supports this improvement by enabling direct dispatch of work to workqueues rather than having to delay the actual work dispatch to the DM cache core. So the dm-cache policies are much more nimble by being able to drive IO as they see fit. One immediate benefit from the improved latency is a cache that should be much more adaptive to changing workloads. - Add a new DM integrity target that emulates a block device that has additional per-sector tags that can be used for storing integrity information. - Add a new authenticated encryption feature to the DM crypt target that builds on the capabilities provided by the DM integrity target. - Add MD interface for switching the raid4/5/6 journal mode and update the DM raid target to use it to enable aid4/5/6 journal write-back support. - Switch the DM verity target over to using the asynchronous hash crypto API (this helps work better with architectures that have access to off-CPU algorithm providers, which should reduce CPU utilization). - Various request-based DM and DM multipath fixes and improvements from Bart and Christoph. - A DM thinp target fix for a bio structure leak that occurs for each discard IFF discard passdown is enabled. - A fix for a possible deadlock in DM bufio and a fix to re-check the new buffer allocation watermark in the face of competing admin changes to the 'max_cache_size_bytes' tunable. - A couple DM core cleanups. * tag 'for-4.12/dm-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm: (50 commits) dm bufio: check new buffer allocation watermark every 30 seconds dm bufio: avoid a possible ABBA deadlock dm mpath: make it easier to detect unintended I/O request flushes dm mpath: cleanup QUEUE_IF_NO_PATH bit manipulation by introducing assign_bit() dm mpath: micro-optimize the hot path relative to MPATHF_QUEUE_IF_NO_PATH dm: introduce enum dm_queue_mode to cleanup related code dm mpath: verify __pg_init_all_paths locking assumptions at runtime dm: verify suspend_locking assumptions at runtime dm block manager: remove an unused argument from dm_block_manager_create() dm rq: check blk_mq_register_dev() return value in dm_mq_init_request_queue() dm mpath: delay requeuing while path initialization is in progress dm mpath: avoid that path removal can trigger an infinite loop dm mpath: split and rename activate_path() to prepare for its expanded use dm ioctl: prevent stack leak in dm ioctl call dm integrity: use previously calculated log2 of sectors_per_block dm integrity: use hex2bin instead of open-coded variant dm crypt: replace custom implementation of hex2bin() dm crypt: remove obsolete references to per-CPU state dm verity: switch to using asynchronous hash crypto API dm crypt: use WQ_HIGHPRI for the IO and crypt workqueues ...
| * dm: add integrity targetMikulas Patocka2017-03-241-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The dm-integrity target emulates a block device that has additional per-sector tags that can be used for storing integrity information. A general problem with storing integrity tags with every sector is that writing the sector and the integrity tag must be atomic - i.e. in case of crash, either both sector and integrity tag or none of them is written. To guarantee write atomicity the dm-integrity target uses a journal. It writes sector data and integrity tags into a journal, commits the journal and then copies the data and integrity tags to their respective location. The dm-integrity target can be used with the dm-crypt target - in this situation the dm-crypt target creates the integrity data and passes them to the dm-integrity target via bio_integrity_payload attached to the bio. In this mode, the dm-crypt and dm-integrity targets provide authenticated disk encryption - if the attacker modifies the encrypted device, an I/O error is returned instead of random data. The dm-integrity target can also be used as a standalone target, in this mode it calculates and verifies the integrity tag internally. In this mode, the dm-integrity target can be used to detect silent data corruption on the disk or in the I/O path. Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Milan Broz <gmazyland@gmail.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
| * dm cache: significant rework to leverage dm-bio-prison-v2Joe Thornber2017-03-071-3/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The cache policy interfaces have been updated to work well with the new bio-prison v2 interface's ability to queue work immediately (promotion, demotion, etc) -- overriding benefit being reduced latency on processing IO through the cache. Previously such work would be left for the DM cache core to queue on various lists and then process in batches later -- this caused a serious delay in latency for IO driven by the cache. The background tracker code was factored out so that all cache policies can make use of it. Also, the "cleaner" policy has been removed and is now a variant of the smq policy that simply disallows migrations. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
| * dm bio prison v2: new interface for the bio prisonJoe Thornber2017-03-071-0/+1
| | | | | | | | | | | | | | | | | | The deferred set is gone and all methods have _v2 appended to the end of their names to allow for continued use of the original bio prison in DM thin-provisioning. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
* | raid5-ppl: Partial Parity Log write logging implementationArtur Paszkiewicz2017-03-161-1/+1
|/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Implement the calculation of partial parity for a stripe and PPL write logging functionality. The description of PPL is added to the documentation. More details can be found in the comments in raid5-ppl.c. Attach a page for holding the partial parity data to stripe_head. Allocate it only if mddev has the MD_HAS_PPL flag set. Partial parity is the xor of not modified data chunks of a stripe and is calculated as follows: - reconstruct-write case: xor data from all not updated disks in a stripe - read-modify-write case: xor old data and parity from all updated disks in a stripe Implement it using the async_tx API and integrate into raid_run_ops(). It must be called when we still have access to old data, so do it when STRIPE_OP_BIODRAIN is set, but before ops_run_prexor5(). The result is stored into sh->ppl_page. Partial parity is not meaningful for full stripe write and is not stored in the log or used for recovery, so don't attempt to calculate it when stripe has STRIPE_FULL_WRITE. Put the PPL metadata structures to md_p.h because userspace tools (mdadm) will also need to read/write PPL. Warn about using PPL with enabled disk volatile write-back cache for now. It can be removed once disk cache flushing before writing PPL is implemented. Signed-off-by: Artur Paszkiewicz <artur.paszkiewicz@intel.com> Signed-off-by: Shaohua Li <shli@fb.com>
* dm: move request-based code out to dm-rq.[hc]Mike Snitzer2016-06-101-1/+2
| | | | | | | | | | | | | | Add some seperation between bio-based and request-based DM core code. 'struct mapped_device' and other DM core only structures and functions have been moved to dm-core.h and all relevant DM core .c files have been updated to include dm-core.h rather than dm.h DM targets should _never_ include dm-core.h! [block core merge conflict resolution from Stephen Rothwell] Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
* dm cache: make the 'mq' policy an alias for 'smq'Joe Thornber2016-03-101-2/+0
| | | | | | | | | | | | 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 <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
* dm verity: add support for forward error correctionSami Tolvanen2015-12-101-0/+4
| | | | | | | | | | | | | | | | | | | | | | | | 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 <samitolvanen@google.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
* dm verity: move dm-verity.c to dm-verity-target.cSami Tolvanen2015-12-101-0/+1
| | | | | | | | Prepare for extending dm-verity with an optional object. Follows the naming convention used by other DM targets (e.g. dm-cache and dm-era). Signed-off-by: Sami Tolvanen <samitolvanen@google.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
* raid5: add basic stripe logShaohua Li2015-10-241-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This introduces a simple log for raid5. Data/parity writing to raid array first writes to the log, then write to raid array disks. If crash happens, we can recovery data from the log. This can speed up raid resync and fix write hole issue. The log structure is pretty simple. Data/meta data is stored in block unit, which is 4k generally. It has only one type of meta data block. The meta data block can track 3 types of data, stripe data, stripe parity and flush block. MD superblock will point to the last valid meta data block. Each meta data block has checksum/seq number, so recovery can scan the log correctly. We store a checksum of stripe data/parity to the metadata block, so meta data and stripe data/parity can be written to log disk together. otherwise, meta data write must wait till stripe data/parity is finished. For stripe data, meta data block will record stripe data sector and size. Currently the size is always 4k. This meta data record can be made simpler if we just fix write hole (eg, we can record data of a stripe's different disks together), but this format can be extended to support caching in the future, which must record data address/size. For stripe parity, meta data block will record stripe sector. It's size should be 4k (for raid5) or 8k (for raid6). We always store p parity first. This format should work for caching too. flush block indicates a stripe is in raid array disks. Fixing write hole doesn't need this type of meta data, it's for caching extension. Signed-off-by: Shaohua Li <shli@fb.com> Signed-off-by: NeilBrown <neilb@suse.com>
* dm cache: add stochastic-multi-queue (smq) policyJoe Thornber2015-06-111-0/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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 <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
* Merge tag 'md/4.1' of git://neil.brown.name/mdLinus Torvalds2015-04-241-0/+1
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Pull md updates from Neil Brown: "More updates that usual this time. A few have performance impacts which hould mostly be positive, but RAID5 (in particular) can be very work-load ensitive... We'll have to wait and see. Highlights: - "experimental" code for managing md/raid1 across a cluster using DLM. Code is not ready for general use and triggers a WARNING if used. However it is looking good and mostly done and having in mainline will help co-ordinate development. - RAID5/6 can now batch multiple (4K wide) stripe_heads so as to handle a full (chunk wide) stripe as a single unit. - RAID6 can now perform read-modify-write cycles which should help performance on larger arrays: 6 or more devices. - RAID5/6 stripe cache now grows and shrinks dynamically. The value set is used as a minimum. - Resync is now allowed to go a little faster than the 'mininum' when there is competing IO. How much faster depends on the speed of the devices, so the effective minimum should scale with device speed to some extent" * tag 'md/4.1' of git://neil.brown.name/md: (58 commits) md/raid5: don't do chunk aligned read on degraded array. md/raid5: allow the stripe_cache to grow and shrink. md/raid5: change ->inactive_blocked to a bit-flag. md/raid5: move max_nr_stripes management into grow_one_stripe and drop_one_stripe md/raid5: pass gfp_t arg to grow_one_stripe() md/raid5: introduce configuration option rmw_level md/raid5: activate raid6 rmw feature md/raid6 algorithms: xor_syndrome() for SSE2 md/raid6 algorithms: xor_syndrome() for generic int md/raid6 algorithms: improve test program md/raid6 algorithms: delta syndrome functions raid5: handle expansion/resync case with stripe batching raid5: handle io error of batch list RAID5: batch adjacent full stripe write raid5: track overwrite disk count raid5: add a new flag to track if a stripe can be batched raid5: use flex_array for scribble data md raid0: access mddev->queue (request queue member) conditionally because it is not set when accessed from dm-raid md: allow resync to go faster when there is competing IO. md: remove 'go_faster' option from ->sync_request() ...
| * Create a separate module for clustering supportGoldwyn Rodrigues2015-02-231-0/+1
| | | | | | | | | | | | Tagged as EXPERIMENTAL for now. Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
* | dm: add log writes targetJosef Bacik2015-04-151-0/+1
|/ | | | | | | | | | | | | Introduce a new target that is meant for file system developers to test file system integrity at particular points in the life of a file system. We capture all write requests and associated data and log them to a separate device for later replay. There is a userspace utility to do this replay. The idea behind this is to give file system developers a tool to verify that the file system is always consistent. Signed-off-by: Josef Bacik <jbacik@fb.com> Reviewed-by: Zach Brown <zab@zabbo.net> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
* dm: add era targetJoe Thornber2014-03-271-0/+2
| | | | | | | | | | | | | | | | | dm-era is a target that behaves similar to the linear target. In addition it keeps track of which blocks were written within a user defined period of time called an 'era'. Each era target instance maintains the current era as a monotonically increasing 32-bit counter. Use cases include tracking changed blocks for backup software, and partially invalidating the contents of a cache to restore cache coherency after rolling back a vendor snapshot. dm-era is primarily expected to be paired with the dm-cache target. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
* dm sysfs: fix a module unload raceMikulas Patocka2014-01-141-0/+1
| | | | | | | | | | | | | | | | | | | | | | | This reverts commit be35f48610 ("dm: wait until embedded kobject is released before destroying a device") and provides an improved fix. The kobject release code that calls the completion must be placed in a non-module file, otherwise there is a module unload race (if the process calling dm_kobject_release is preempted and the DM module unloaded after the completion is triggered, but before dm_kobject_release returns). To fix this race, this patch moves the completion code to dm-builtin.c which is always compiled directly into the kernel if BLK_DEV_DM is selected. The patch introduces a new dm_kobject_holder structure, its purpose is to keep the completion and kobject in one place, so that it can be accessed from non-module code without the need to export the layout of struct mapped_device to that code. Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Cc: stable@vger.kernel.org
* dm: add statistics supportMikulas Patocka2013-09-051-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | Support the collection of I/O statistics on user-defined regions of a DM device. If no regions are defined no statistics are collected so there isn't any performance impact. Only bio-based DM devices are currently supported. Each user-defined region specifies a starting sector, length and step. Individual statistics will be collected for each step-sized area within the range specified. The I/O statistics counters for each step-sized area of a region are in the same format as /sys/block/*/stat or /proc/diskstats but extra counters (12 and 13) are provided: total time spent reading and writing in milliseconds. All these counters may be accessed by sending the @stats_print message to the appropriate DM device via dmsetup. The creation of DM statistics will allocate memory via kmalloc or fallback to using vmalloc space. At most, 1/4 of the overall system memory may be allocated by DM statistics. The admin can see how much memory is used by reading /sys/module/dm_mod/parameters/stats_current_allocated_bytes See Documentation/device-mapper/statistics.txt for more details. Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
* dm: add switch targetJim Ramsay2013-07-101-0/+1
| | | | | | | | | | | | | | | | | dm-switch is a new target that maps IO to underlying block devices efficiently when there is a large number of fixed-sized address regions but there is no simple pattern to allow for a compact mapping representation such as dm-stripe. Though we have developed this target for a specific storage device, Dell EqualLogic, we have made an effort to keep it as general purpose as possible in the hope that others may benefit. Originally developed by Jim Ramsay. Simplified by Mikulas Patocka. Signed-off-by: Jim Ramsay <jim_ramsay@dell.com> Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
* bcache: A block layer cacheKent Overstreet2013-03-231-0/+1
| | | | | | | | | Does writethrough and writeback caching, handles unclean shutdown, and has a bunch of other nifty features motivated by real world usage. See the wiki at http://bcache.evilpiepirate.org for more. Signed-off-by: Kent Overstreet <koverstreet@google.com>
* dm cache: add cleaner policyHeinz Mauelshagen2013-03-011-0/+2
| | | | | | | | | | A simple cache policy that writes back all data to the origin. This is used to decommission a dm cache by emptying it. Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
* dm cache: add mq policyJoe Thornber2013-03-011-0/+2
| | | | | | | | | | A cache policy that uses a multiqueue ordered by recent hit count to select which blocks should be promoted and demoted. This is meant to be a general purpose policy. It prioritises reads over writes. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
* dm: add cache targetJoe Thornber2013-03-011-0/+2
| | | | | | | | | | | | | | | | Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
* dm thin: move bio_prison code to separate moduleMike Snitzer2012-10-121-0/+1
| | | | | | | | | The bio prison code will be useful to other future DM targets so move it to a separate module. Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
* dm: add verity targetMikulas Patocka2012-03-281-0/+1
| | | | | | | | | | | | | | | | | | | | This device-mapper target creates a read-only device that transparently validates the data on one underlying device against a pre-generated tree of cryptographic checksums stored on a second device. Two checksum device formats are supported: version 0 which is already shipping in Chromium OS and version 1 which incorporates some improvements. Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Mandeep Singh Baines <msb@chromium.org> Signed-off-by: Will Drewry <wad@chromium.org> Signed-off-by: Elly Jones <ellyjones@chromium.org> Cc: Milan Broz <mbroz@redhat.com> Cc: Olof Johansson <olofj@chromium.org> Cc: Steffen Klassert <steffen.klassert@secunet.com> Cc: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
* dm: add thin provisioning targetJoe Thornber2011-10-311-0/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | Initial EXPERIMENTAL implementation of device-mapper thin provisioning with snapshot support. The 'thin' target is used to create instances of the virtual devices that are hosted in the 'thin-pool' target. The thin-pool target provides data sharing among devices. This sharing is made possible using the persistent-data library in the previous patch. The main highlight of this implementation, compared to the previous implementation of snapshots, is that it allows many virtual devices to be stored on the same data volume, simplifying administration and allowing sharing of data between volumes (thus reducing disk usage). Another big feature is support for arbitrary depth of recursive snapshots (snapshots of snapshots of snapshots ...). The previous implementation of snapshots did this by chaining together lookup tables, and so performance was O(depth). This new implementation uses a single data structure so we don't get this degradation with depth. For further information and examples of how to use this, please read Documentation/device-mapper/thin-provisioning.txt Signed-off-by: Joe Thornber <thornber@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
* dm: add bufioMikulas Patocka2011-10-311-0/+1
| | | | | | | | | | | | | | | | | | The dm-bufio interface allows you to do cached I/O on devices, holding recently-read blocks in memory and performing delayed writes. We don't use buffer cache or page cache already present in the kernel, because: * we need to handle block sizes larger than a page * we can't allocate memory to perform reads or we'd have deadlocks Currently, when a cache is required, we limit its size to a fraction of available memory. Usage can be viewed and changed in /sys/module/dm_bufio/parameters/ . The first user is thin provisioning, but more dm users are planned. Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
* dm: add flakey targetJosef Bacik2011-03-241-0/+1
| | | | | | | | | | | | This target is the same as the linear target except that it returns I/O errors periodically. It's been found useful in simulating failing devices for testing purposes. I needed a dm target to do some failure testing on btrfs's raid code, and Mike pointed me at this. Signed-off-by: Josef Bacik <josef@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
* dm: raid456 basic supportNeilBrown2011-01-131-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch is the skeleton for the DM target that will be the bridge from DM to MD (initially RAID456 and later RAID1). It provides a way to use device-mapper interfaces to the MD RAID456 drivers. As with all device-mapper targets, the nominal public interfaces are the constructor (CTR) tables and the status outputs (both STATUSTYPE_INFO and STATUSTYPE_TABLE). The CTR table looks like the following: 1: <s> <l> raid \ 2: <raid_type> <#raid_params> <raid_params> \ 3: <#raid_devs> <meta_dev1> <dev1> .. <meta_devN> <devN> Line 1 contains the standard first three arguments to any device-mapper target - the start, length, and target type fields. The target type in this case is "raid". Line 2 contains the arguments that define the particular raid type/personality/level, the required arguments for that raid type, and any optional arguments. Possible raid types include: raid4, raid5_la, raid5_ls, raid5_rs, raid6_zr, raid6_nr, and raid6_nc. (again, raid1 is planned for the future.) The list of required and optional parameters is the same for all the current raid types. The required parameters are positional, while the optional parameters are given as key/value pairs. The possible parameters are as follows: <chunk_size> Chunk size in sectors. [[no]sync] Force/Prevent RAID initialization [rebuild <idx>] Rebuild the drive indicated by the index [daemon_sleep <ms>] Time between bitmap daemon work to clear bits [min_recovery_rate <kB/sec/disk>] Throttle RAID initialization [max_recovery_rate <kB/sec/disk>] Throttle RAID initialization [max_write_behind <value>] See '-write-behind=' (man mdadm) [stripe_cache <sectors>] Stripe cache size for higher RAIDs Line 3 contains the list of devices that compose the array in metadata/data device pairs. If the metadata is stored separately, a '-' is given for the metadata device position. If a drive has failed or is missing at creation time, a '-' can be given for both the metadata and data drives for a given position. Examples: # RAID4 - 4 data drives, 1 parity # No metadata devices specified to hold superblock/bitmap info # Chunk size of 1MiB # (Lines separated for easy reading) 0 1960893648 raid \ raid4 1 2048 \ 5 - 8:17 - 8:33 - 8:49 - 8:65 - 8:81 # RAID4 - 4 data drives, 1 parity (no metadata devices) # Chunk size of 1MiB, force RAID initialization, # min recovery rate at 20 kiB/sec/disk 0 1960893648 raid \ raid4 4 2048 min_recovery_rate 20 sync\ 5 - 8:17 - 8:33 - 8:49 - 8:65 - 8:81 Performing a 'dmsetup table' should display the CTR table used to construct the mapping (with possible reordering of optional parameters). Performing a 'dmsetup status' will yield information on the state and health of the array. The output is as follows: 1: <s> <l> raid \ 2: <raid_type> <#devices> <1 health char for each dev> <resync_ratio> Line 1 is standard DM output. Line 2 is best shown by example: 0 1960893648 raid raid4 5 AAAAA 2/490221568 Here we can see the RAID type is raid4, there are 5 devices - all of which are 'A'live, and the array is 2/490221568 complete with recovery. Cc: linux-raid@vger.kernel.org Signed-off-by: NeilBrown <neilb@suse.de> Signed-off-by: Jonathan Brassow <jbrassow@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
* Merge branch 'async' of macbook:git/btrfs-unstableDavid Woodhouse2010-08-091-77/+0
|\ | | | | | | | | | | Conflicts: drivers/md/Makefile lib/raid6/unroll.pl
| * md: Factor out RAID6 algorithms into lib/David Woodhouse2009-10-291-76/+0
| | | | | | | | | | | | We'll want to use these in btrfs too. Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
* | md: drivers/md/unroll.pl replaced with awk analogVladimir Dronnikov2009-10-161-11/+11
|/ | | | | | | | drivers/md/unroll.pl replaced by awk script to drop build-time dependency on perl Signed-off-by: Vladimir Dronnikov <dronnikov@gmail.com> Signed-off-by: NeilBrown <neilb@suse.de>
* dm raid1: add userspace logJonthan Brassow2009-06-221-0/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch contains a device-mapper mirror log module that forwards requests to userspace for processing. The structures used for communication between kernel and userspace are located in include/linux/dm-log-userspace.h. Due to the frequency, diversity, and 2-way communication nature of the exchanges between kernel and userspace, 'connector' was chosen as the interface for communication. The first log implementations written in userspace - "clustered-disk" and "clustered-core" - support clustered shared storage. A userspace daemon (in the LVM2 source code repository) uses openAIS/corosync to process requests in an ordered fashion with the rest of the nodes in the cluster so as to prevent log state corruption. Other implementations with no association to LVM or openAIS/corosync, are certainly possible. (Imagine if two machines are writing to the same region of a mirror. They would both mark the region dirty, but you need a cluster-aware entity that can handle properly marking the region clean when they are done. Otherwise, you might clear the region when the first machine is done, not the second.) Signed-off-by: Jonathan Brassow <jbrassow@redhat.com> Cc: Evgeniy Polyakov <johnpol@2ka.mipt.ru> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
* dm mpath: add service time load balancerKiyoshi Ueda2009-06-221-0/+1
| | | | | | | | | | | | | | | | This patch adds a service time oriented dynamic load balancer, dm-service-time, which selects the path with the shortest estimated service time for the incoming I/O. The service time is estimated by dividing the in-flight I/O size by a performance value of each path. The performance value can be given as a table argument at the table loading time. If no performance value is given, all paths are considered equal. Signed-off-by: Kiyoshi Ueda <k-ueda@ct.jp.nec.com> Signed-off-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
* dm mpath: add queue length load balancerKiyoshi Ueda2009-06-221-0/+1
| | | | | | | | | | | | | This patch adds a dynamic load balancer, dm-queue-length, which balances the number of in-flight I/Os across the paths. The code is based on the patch posted by Stefan Bader: https://www.redhat.com/archives/dm-devel/2005-October/msg00050.html Signed-off-by: Stefan Bader <stefan.bader@canonical.com> Signed-off-by: Kiyoshi Ueda <k-ueda@ct.jp.nec.com> Signed-off-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
* md/raid6: move raid6 data processing to raid6_pq.koDan Williams2009-03-311-1/+3
| | | | | | | | | | | | | | | | | Move the raid6 data processing routines into a standalone module (raid6_pq) to prepare them to be called from async_tx wrappers and other non-md drivers/modules. This precludes a circular dependency of raid456 needing the async modules for data processing while those modules in turn depend on raid456 for the base level synchronous raid6 routines. To support this move: 1/ The exportable definitions in raid6.h move to include/linux/raid/pq.h 2/ The raid6_call, recovery calls, and table symbols are exported 3/ Extra #ifdef __KERNEL__ statements to enable the userspace raid6test to compile Signed-off-by: Dan Williams <dan.j.williams@intel.com> Signed-off-by: NeilBrown <neilb@suse.de>
* cleanup drivers/md/MakefileChristoph Hellwig2009-03-311-7/+7
| | | | | | | | | | Use the -y variables instead of the old -objs so we can easily add conditional objects to the modules. Also always use += to add subobjects to avoid problems when placing additional objects in some place in the file. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: NeilBrown <neilb@suse.de>
* dm snapshot: split out exception store implementationsAlasdair G Kergon2009-01-061-1/+2
| | | | | | | | Move the existing snapshot exception store implementations out into separate files. Later patches will place these behind a new interface in preparation for alternative implementations. Signed-off-by: Alasdair G Kergon <agk@redhat.com>
* dm: add name and uuid to sysfsMilan Broz2009-01-061-1/+1
| | | | | | | | | | | | | | | | | | | | | Implement simple read-only sysfs entry for device-mapper block device. This patch adds a simple sysfs directory named "dm" under block device properties and implements - name attribute (string containing mapped device name) - uuid attribute (string containing UUID, or empty string if not set) The kobject is embedded in mapped_device struct, so no additional memory allocation is needed for initializing sysfs entry. During the processing of sysfs attribute we need to lock mapped device which is done by a new function dm_get_from_kobj, which returns the md associated with kobject and increases the usage count. Each 'show attribute' function is responsible for its own locking. Signed-off-by: Milan Broz <mbroz@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
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