DOCSLIB.ORG

UBI - Unsorted Block Images

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
UBI - Unsorted Block Images UBI - Unsorted Block Images Thomas Gleixner Frank Haverkamp Artem Bityutskiy UBI - Unsorted Block Images by Thomas Gleixner, Frank Haverkamp, and Artem Bityutskiy Copyright © 2006 International Business Machines Corp. Revision History Revision v1.0.0 2006-06-09 Revised by: haver Release Version. Table of Contents 1. Document conventions...........................................................................................................................1 2. Introduction............................................................................................................................................2 UBI Volumes......................................................................................................................................2 Static Volumes ..........................................................................................................................2 Dynamic Volumes.....................................................................................................................3 3. MTD integration ....................................................................................................................................4 Simple partitioning.............................................................................................................................4 Complex partitioning .........................................................................................................................5 4. UBI design ..............................................................................................................................................6 Eraseblock assignement .....................................................................................................................6 Enhancements...........................................................................................................................6 Eraseblock headers.............................................................................................................................7 General Header format .............................................................................................................8 Erase counter format.................................................................................................................8 Volume identifier format...........................................................................................................9 Erase counter update atomicity ..............................................................................................10 Volumes............................................................................................................................................10 The layout volume..................................................................................................................11 Robustness ....................................................................................................................11 FLASH space requirements .............................................................................................................12 Spare erase blocks ..................................................................................................................12 Bad block parameter .....................................................................................................12 Robustness ....................................................................................................................12 Space calculation....................................................................................................................13 Volume management........................................................................................................................13 Volume creation......................................................................................................................14 Volume deletion......................................................................................................................14 Volume resizing ......................................................................................................................14 Logical blocks ..................................................................................................................................14 Block management...........................................................................................................................15 Block allocation......................................................................................................................15 Block erasure..........................................................................................................................15 Block content movement........................................................................................................15 Static volumes...............................................................................................................16 Dynamic volumes .........................................................................................................16 Scrubbing ......................................................................................................................17 UBI Initialization .............................................................................................................................18 Future enhancements..............................................................................................................18 Background operation ......................................................................................................................18 Wear leveling....................................................................................................................................18 Enhancements.........................................................................................................................19 Volume update..................................................................................................................................19 Volume readout ................................................................................................................................20 iii 5. Programming Interfaces .....................................................................................................................21 Kernel Space ....................................................................................................................................21 read .........................................................................................................................................21 write........................................................................................................................................22 erase........................................................................................................................................22 get_volume .............................................................................................................................23 put_volume .............................................................................................................................23 Enhanced: move_update.........................................................................................................23 Userspace Interface UBI ..................................................................................................................24 sysfs interface .........................................................................................................................24 Deviceinfo (sysfs) .........................................................................................................24 Volumeinfo (sysfs) ........................................................................................................25 Examples.......................................................................................................................25 UBI device I/O functions........................................................................................................25 create_volume ...............................................................................................................26 delete_volume ...............................................................................................................26 resize_volume ...............................................................................................................26 UBI volume I/O functions ......................................................................................................27 start_update ioctl...........................................................................................................27 open...............................................................................................................................28 llseek .............................................................................................................................28 read................................................................................................................................28 write ..............................................................................................................................28 Volume update write mode..................................................................................28 Enhancement: Dynamic volume write mode ......................................................29
Load more

Recommended publications
  • Development of a Verified Flash File System ⋆
    Development of a Verified Flash File System ? Gerhard Schellhorn, Gidon Ernst, J¨orgPf¨ahler,Dominik Haneberg, and Wolfgang Reif Institute for Software & Systems Engineering University of Augsburg, Germany fschellhorn,ernst,joerg.pfaehler,haneberg,reifg @informatik.uni-augsburg.de Abstract. This paper gives an overview over the development of a for- mally verified file system for flash memory. We describe our approach that is based on Abstract State Machines and incremental modular re- finement. Some of the important intermediate levels and the features they introduce are given. We report on the verification challenges addressed so far, and point to open problems and future work. We furthermore draw preliminary conclusions on the methodology and the required tool support. 1 Introduction Flaws in the design and implementation of file systems already lead to serious problems in mission-critical systems. A prominent example is the Mars Explo- ration Rover Spirit [34] that got stuck in a reset cycle. In 2013, the Mars Rover Curiosity also had a bug in its file system implementation, that triggered an au- tomatic switch to safe mode. The first incident prompted a proposal to formally verify a file system for flash memory [24,18] as a pilot project for Hoare's Grand Challenge [22]. We are developing a verified flash file system (FFS). This paper reports on our progress and discusses some of the aspects of the project. We describe parts of the design, the formal models, and proofs, pointing out challenges and solutions. The main characteristic of flash memory that guides the design is that data cannot be overwritten in place, instead space can only be reused by erasing whole blocks.
    [Show full text]
  • Userland Tools and Techniques for Board Bring up and Systems Integration
    Userland Tools and Techniques for Board Bring Up and Systems Integration ELC 2012 HY Research LLC http://www.hy-research.com/ Feb 5, 2012 (C) 2012 HY Research LLC Agenda * Introduction * What? * Why bother with userland? * Common SoC interfaces * Typical Scenario * Kernel setup * GPIO/UART/I2C/SPI/Other * Questions HY Research LLC http://www.hy-research.com/ Feb 5, 2012 (C) 2012 HY Research LLC Introduction * SoC offer a lot of integrated functionality * System designs differ by outside parts * Most mobile systems are SoC * "CPU boards" for SoCs * Available BSP for starting * Vendor or other sources * Common Unique components * Memory (RAM) * Storage ("flash") * IO * Displays HY Research LLC * Power supplies http://www.hy-research.com/ Feb 5, 2012 (C) 2012 HY Research LLC What? * IO related items * I2C * SPI * UART * GPIO * USB HY Research LLC http://www.hy-research.com/ Feb 5, 2012 (C) 2012 HY Research LLC Why userland? * Easier for non kernel savy * Quicker turn around time * Easier to debug * Often times available already Sample userland from BSP/LSP vendor * Kernel driver is not ready HY Research LLC http://www.hy-research.com/ Feb 5, 2012 (C) 2012 HY Research LLC Common SoC interfaces Most SoC have these and more: * Pinmux * UART * GPIO * I2C * SPI * USB * Not discussed: Audio/Displays HY Research LLC http://www.hy-research.com/ Feb 5, 2012 (C) 2012 HY Research LLC Typical Scenario Custom board: * Load code/Bring up memory * Setup memory controller for part used * Load Linux * Toggle lines on board to verify Prototype based on demo/eval board: * Start with board at a shell prompt * Get newly attached hw to work HY Research LLC http://www.hy-research.com/ Feb 5, 2012 (C) 2012 HY Research LLC Kernel Setup Additions to typical configs: * Enable UART support (typically done already) * Enable I2C support along with drivers for the SoC * (CONFIG_I2C + other) * Enable SPIdev * (CONFIG_SPI + CONFIG_SPI_SPIDEV) * Add SPIDEV to board file * Enable GPIO sysfs * (CONFIG_GPIO + other + CONFIG_GPIO_SYSFS) * Enable USB * Depends on OTG vs normal, etc.
    [Show full text]
  • Flexible Lustre Management
    Flexible Lustre management Making less work for Admins ORNL is managed by UT-Battelle for the US Department of Energy How do we know Lustre condition today • Polling proc / sysfs files – The knocking on the door model – Parse stats, rpc info, etc for performance deviations. • Constant collection of debug logs – Heavy parsing for common problems. • The death of a node – Have to examine kdumps and /or lustre dump Origins of a new approach • Requirements for Linux kernel integration. – No more proc usage – Migration to sysfs and debugfs – Used to configure your file system. – Started in lustre 2.9 and still on going. • Two ways to configure your file system. – On MGS server run lctl conf_param … • Directly accessed proc seq_files. – On MSG server run lctl set_param –P • Originally used an upcall to lctl for configuration • Introduced in Lustre 2.4 but was broken until lustre 2.12 (LU-7004) – Configuring file system works transparently before and after sysfs migration. Changes introduced with sysfs / debugfs migration • sysfs has a one item per file rule. • Complex proc files moved to debugfs • Moving to debugfs introduced permission problems – Only debugging files should be their. – Both debugfs and procfs have scaling issues. • Moving to sysfs introduced the ability to send uevents – Item of most interest from LUG 2018 Linux Lustre client talk. – Both lctl conf_param and lctl set_param –P use this approach • lctl conf_param can set sysfs attributes without uevents. See class_modify_config() – We get life cycle events for free – udev is now involved. What do we get by using udev ? • Under the hood – uevents are collect by systemd and then processed by udev rules – /etc/udev/rules.d/99-lustre.rules – SUBSYSTEM=="lustre", ACTION=="change", ENV{PARAM}=="?*", RUN+="/usr/sbin/lctl set_param '$env{PARAM}=$env{SETTING}’” • You can create your own udev rule – http://reactivated.net/writing_udev_rules.html – /lib/udev/rules.d/* for examples – Add udev_log="debug” to /etc/udev.conf if you have problems • Using systemd for long task.
    [Show full text]
  • ECE 598 – Advanced Operating Systems Lecture 19
    ECE 598 { Advanced Operating Systems Lecture 19 Vince Weaver http://web.eece.maine.edu/~vweaver [email protected] 7 April 2016 Announcements • Homework #7 was due • Homework #8 will be posted 1 Why use FAT over ext2? • FAT simpler, easy to code • FAT supported on all major OSes • ext2 faster, more robust filename and permissions 2 btrfs • B-tree fs (similar to a binary tree, but with pages full of leaves) • overwrite filesystem (overwite on modify) vs CoW • Copy on write. When write to a file, old data not overwritten. Since old data not over-written, crash recovery better Eventually old data garbage collected • Data in extents 3 • Copy-on-write • Forest of trees: { sub-volumes { extent-allocation { checksum tree { chunk device { reloc • On-line defragmentation • On-line volume growth 4 • Built-in RAID • Transparent compression • Snapshots • Checksums on data and meta-data • De-duplication • Cloning { can make an exact snapshot of file, copy-on- write different than link, different inodles but same blocks 5 Embedded • Designed to be small, simple, read-only? • romfs { 32 byte header (magic, size, checksum,name) { Repeating files (pointer to next [0 if none]), info, size, checksum, file name, file data • cramfs 6 ZFS Advanced OS from Sun/Oracle. Similar in idea to btrfs indirect still, not extent based? 7 ReFS Resilient FS, Microsoft's answer to brtfs and zfs 8 Networked File Systems • Allow a centralized file server to export a filesystem to multiple clients. • Provide file level access, not just raw blocks (NBD) • Clustered filesystems also exist, where multiple servers work in conjunction.
    [Show full text]
  • [13주차] Sysfs and Procfs
    1 7 Computer Core Practice1: Operating System Week13. sysfs and procfs Jhuyeong Jhin and Injung Hwang Embedded Software Lab. Embedded Software Lab. 2 sysfs 7 • A pseudo file system provided by the Linux kernel. • sysfs exports information about various kernel subsystems, HW devices, and associated device drivers to user space through virtual files. • The mount point of sysfs is usually /sys. • sysfs abstrains devices or kernel subsystems as a kobject. Embedded Software Lab. 3 How to create a file in /sys 7 1. Create and add kobject to the sysfs 2. Declare a variable and struct kobj_attribute – When you declare the kobj_attribute, you should implement the functions “show” and “store” for reading and writing from/to the variable. – One variable is one attribute 3. Create a directory in the sysfs – The directory have attributes as files • When the creation of the directory is completed, the directory and files(attributes) appear in /sys. • Reference: ${KERNEL_SRC_DIR}/include/linux/sysfs.h ${KERNEL_SRC_DIR}/fs/sysfs/* • Example : ${KERNEL_SRC_DIR}/kernel/ksysfs.c Embedded Software Lab. 4 procfs 7 • A special filesystem in Unix-like operating systems. • procfs presents information about processes and other system information in a hierarchical file-like structure. • Typically, it is mapped to a mount point named /proc at boot time. • procfs acts as an interface to internal data structures in the kernel. The process IDs of all processes in the system • Kernel provides a set of functions which are designed to make the operations for the file in /proc : “seq_file interface”. – We will create a file in procfs and print some data from data structure by using this interface.
    [Show full text]
  • Singularityce User Guide Release 3.8
    SingularityCE User Guide Release 3.8 SingularityCE Project Contributors Aug 16, 2021 CONTENTS 1 Getting Started & Background Information3 1.1 Introduction to SingularityCE......................................3 1.2 Quick Start................................................5 1.3 Security in SingularityCE........................................ 15 2 Building Containers 19 2.1 Build a Container............................................. 19 2.2 Definition Files.............................................. 24 2.3 Build Environment............................................ 35 2.4 Support for Docker and OCI....................................... 39 2.5 Fakeroot feature............................................. 79 3 Signing & Encryption 83 3.1 Signing and Verifying Containers.................................... 83 3.2 Key commands.............................................. 88 3.3 Encrypted Containers.......................................... 90 4 Sharing & Online Services 95 4.1 Remote Endpoints............................................ 95 4.2 Cloud Library.............................................. 103 5 Advanced Usage 109 5.1 Bind Paths and Mounts.......................................... 109 5.2 Persistent Overlays............................................ 115 5.3 Running Services............................................. 118 5.4 Environment and Metadata........................................ 129 5.5 OCI Runtime Support.......................................... 140 5.6 Plugins.................................................
    [Show full text]
  • Recursive Updates in Copy-On-Write File Systems - Modeling and Analysis
    2342 JOURNAL OF COMPUTERS, VOL. 9, NO. 10, OCTOBER 2014 Recursive Updates in Copy-on-write File Systems - Modeling and Analysis Jie Chen*, Jun Wang†, Zhihu Tan*, Changsheng Xie* *School of Computer Science and Technology Huazhong University of Science and Technology, China *Wuhan National Laboratory for Optoelectronics, Wuhan, Hubei 430074, China [email protected], {stan, cs_xie}@hust.edu.cn †Dept. of Electrical Engineering and Computer Science University of Central Florida, Orlando, Florida 32826, USA [email protected] Abstract—Copy-On-Write (COW) is a powerful technique recursive update. Recursive updates can lead to several for data protection in file systems. Unfortunately, it side effects to a storage system, such as write introduces a recursively updating problem, which leads to a amplification (also can be referred as additional writes) side effect of write amplification. Studying the behaviors of [4], I/O pattern alternation [5], and performance write amplification is important for designing, choosing and degradation [6]. This paper focuses on the side effects of optimizing the next generation file systems. However, there are many difficulties for evaluation due to the complexity of write amplification. file systems. To solve this problem, we proposed a typical Studying the behaviors of write amplification is COW file system model based on BTRFS, verified its important for designing, choosing, and optimizing the correctness through carefully designed experiments. By next generation file systems, especially when the file analyzing this model, we found that write amplification is systems uses a flash-memory-based underlying storage greatly affected by the distributions of files being accessed, system under online transaction processing (OLTP) which varies from 1.1x to 4.2x.
    [Show full text]
  • F2punifycr: a Flash-Friendly Persistent Burst-Buffer File System
    F2PUnifyCR: A Flash-friendly Persistent Burst-Buffer File System ThanOS Department of Computer Science Florida State University Tallahassee, United States I. ABSTRACT manifold depending on the workloads it is handling for With the increased amount of supercomputing power, applications. In order to leverage the capabilities of burst it is now possible to work with large scale data that buffers to the utmost level, it is very important to have a pose a continuous opportunity for exascale computing standardized software interface across systems. It has to that puts immense pressure on underlying persistent data deal with an immense amount of data during the runtime storage. Burst buffers, a distributed array of node-local of the applications. persistent flash storage devices deployed on most of Using node-local burst buffer can achieve scalable the leardership supercomputers, are means to efficiently write bandwidth as it lets each process write to the handling the bursty I/O invoked through cutting-edge local flash drive, but when the files are shared across scientific applications. In order to manage these burst many processes, it puts the management of metadata buffers, many ephemeral user level file system solutions, and object data of the files under huge challenge. In like UnifyCR, are present in the research and industry order to handle all the challenges posed by the bursty arena. Because of the intrinsic nature of the flash devices and random I/O requests by the Scientific Applica- due to background processing overhead, like Garbage tions running on leadership Supercomputing clusters, Collection, peak write bandwidth is hard to get.
    [Show full text]
  • Ubuntu Server Guide Basic Installation Preparing to Install
    Ubuntu Server Guide Welcome to the Ubuntu Server Guide! This site includes information on using Ubuntu Server for the latest LTS release, Ubuntu 20.04 LTS (Focal Fossa). For an offline version as well as versions for previous releases see below. Improving the Documentation If you find any errors or have suggestions for improvements to pages, please use the link at thebottomof each topic titled: “Help improve this document in the forum.” This link will take you to the Server Discourse forum for the specific page you are viewing. There you can share your comments or let us know aboutbugs with any page. PDFs and Previous Releases Below are links to the previous Ubuntu Server release server guides as well as an offline copy of the current version of this site: Ubuntu 20.04 LTS (Focal Fossa): PDF Ubuntu 18.04 LTS (Bionic Beaver): Web and PDF Ubuntu 16.04 LTS (Xenial Xerus): Web and PDF Support There are a couple of different ways that the Ubuntu Server edition is supported: commercial support and community support. The main commercial support (and development funding) is available from Canonical, Ltd. They supply reasonably- priced support contracts on a per desktop or per-server basis. For more information see the Ubuntu Advantage page. Community support is also provided by dedicated individuals and companies that wish to make Ubuntu the best distribution possible. Support is provided through multiple mailing lists, IRC channels, forums, blogs, wikis, etc. The large amount of information available can be overwhelming, but a good search engine query can usually provide an answer to your questions.
    [Show full text]
  • Architecture and Performance of Perlmutter's 35 PB Clusterstor
    Lawrence Berkeley National Laboratory Recent Work Title Architecture and Performance of Perlmutter’s 35 PB ClusterStor E1000 All-Flash File System Permalink https://escholarship.org/uc/item/90r3s04z Authors Lockwood, Glenn K Chiusole, Alberto Gerhardt, Lisa et al. Publication Date 2021-06-18 Peer reviewed eScholarship.org Powered by the California Digital Library University of California Architecture and Performance of Perlmutter’s 35 PB ClusterStor E1000 All-Flash File System Glenn K. Lockwood, Alberto Chiusole, Lisa Gerhardt, Kirill Lozinskiy, David Paul, Nicholas J. Wright Lawrence Berkeley National Laboratory fglock, chiusole, lgerhardt, klozinskiy, dpaul, [email protected] Abstract—NERSC’s newest system, Perlmutter, features a 35 1,536 GPU nodes 16 Lustre MDSes PB all-flash Lustre file system built on HPE Cray ClusterStor 1x AMD Epyc 7763 1x AMD Epyc 7502 4x NVIDIA A100 2x Slingshot NICs E1000. We present its architecture, early performance figures, 4x Slingshot NICs Slingshot Network 24x 15.36 TB NVMe and performance considerations unique to this architecture. We 200 Gb/s demonstrate the performance of E1000 OSSes through low-level 2-level dragonfly 16 Lustre OSSes 3,072 CPU nodes Lustre tests that achieve over 90% of the theoretical bandwidth 1x AMD Epyc 7502 2x AMD Epyc 7763 2x Slingshot NICs of the SSDs at the OST and LNet levels. We also show end-to-end 1x Slingshot NICs performance for both traditional dimensions of I/O performance 24x 15.36 TB NVMe (peak bulk-synchronous bandwidth) and non-optimal workloads endemic to production computing (small, incoherent I/Os at 24 Gateway nodes 2 Arista 7804 routers 2x Slingshot NICs 400 Gb/s/port random offsets) and compare them to NERSC’s previous system, 2x 200G HCAs > 10 Tb/s routing Cori, to illustrate that Perlmutter achieves the performance of a burst buffer and the resilience of a scratch file system.
    [Show full text]
  • How to Avoid Writing Kernel Drivers
    How to avoid writing kernel drivers Chris Simmonds Embedded Linux Conference Europe 2018 How to avoid writing kernel drivers1 Copyright © 2011-2018, 2net Ltd License These slides are available under a Creative Commons Attribution-ShareAlike 3.0 license. You can read the full text of the license here http://creativecommons.org/licenses/by-sa/3.0/legalcode You are free to • copy, distribute, display, and perform the work • make derivative works • make commercial use of the work Under the following conditions • Attribution: you must give the original author credit • Share Alike: if you alter, transform, or build upon this work, you may distribute the resulting work only under a license identical to this one (i.e. include this page exactly as it is) • For any reuse or distribution, you must make clear to others the license terms of this work How to avoid writing kernel drivers2 Copyright © 2011-2018, 2net Ltd About Chris Simmonds • Consultant and trainer • Author of Mastering Embedded Linux Programming • Working with embedded Linux since 1999 • Android since 2009 • Speaker at many conferences and workshops "Looking after the Inner Penguin" blog at http://2net.co.uk/ @2net_software https://uk.linkedin.com/in/chrisdsimmonds/ How to avoid writing kernel drivers3 Copyright © 2011-2018, 2net Ltd Agenda • Device drivers in kernel space • Device drivers in user space • Some examples: • GPIO • PWM • I2C How to avoid writing kernel drivers4 Copyright © 2011-2018, 2net Ltd Conventional device driver model Application User space C library System call handler Linux Generic services kernel Device drivers interrupts Hardware How to avoid writing kernel drivers5 Copyright © 2011-2018, 2net Ltd How applications interact device drivers • In Linux, everything is a file 1 • Applications interact with drivers via POSIX functions open(2), read(2), write(2), ioctl(2), etc • Two main types of interface: 1.
    [Show full text]
  • Get to Grips with /Proc and /Sysfs
    /proc and /sysfs /proc and /sysfs Get to grips with /proc and /sysfs Did you think that ‘everything is a file’ was ancient Unix gibberish? Think again: Juliet Kemp delves into the virtual files that keep your box going. he /proc directory (short for process working in kernel space at all), and for pootling around with to filesystem), is fundamentally a myth: it doesn’t satisfy your own interest in what’s going on under the hood of really exist anywhere at all. Instead, it’s a your system. T virtual filesystem, generated at boot and In older Unices (such as BSD and Solaris), /proc is strictly updated thereafter through interacting with the kernel. process-related, but in Linux it’s extended to non-process It doesn’t use any disk space (because it doesn’t really data as well, making it even more useful. This also means that exist!), and it uses only a small amount of memory. in some cases you can use it to make changes as well as to When you ask to read a read data. This is discussed file, information is retrieved later on in this article: you can by /proc talking to the “The /proc directory is make changes in /proc files that kernel, and then the change system settings on the information is handed back fundamentally a myth: it fly, but you can’t change to you as though it were a doesn’t really exist.” process data by editing files or file. This makes it great both directories in /proc. Which is for communication between different parts of the system (it’s probably for the best, as it could have interesting results! Do used by various utilities, including the GNU version of ps, with be aware when messing around with the bits of /proc that the major security advantage that such utilities can operate are editable that you’re making changes to your system on entirely in userspace, just interacting with /proc rather than the fly and that it’s possible to screw things up… 56 LXF126 Christmas 2009 www.linuxformat.com LXF126.proc 56 22/10/09 4:24:46 pm /proc and /sysfs /proc and /sysfs /proc and processes here are two main sections to /proc: process data and system data.
    [Show full text]