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Diffstat (limited to 'Documentation/admin-guide')
27 files changed, 2260 insertions, 79 deletions
diff --git a/Documentation/admin-guide/auxdisplay/cfag12864b.rst b/Documentation/admin-guide/auxdisplay/cfag12864b.rst new file mode 100644 index 000000000000..18c2865bd322 --- /dev/null +++ b/Documentation/admin-guide/auxdisplay/cfag12864b.rst @@ -0,0 +1,98 @@ +=================================== +cfag12864b LCD Driver Documentation +=================================== + +:License: GPLv2 +:Author & Maintainer: Miguel Ojeda Sandonis +:Date: 2006-10-27 + + + +.. INDEX + + 1. DRIVER INFORMATION + 2. DEVICE INFORMATION + 3. WIRING + 4. USERSPACE PROGRAMMING + +1. Driver Information +--------------------- + +This driver supports a cfag12864b LCD. + + +2. Device Information +--------------------- + +:Manufacturer: Crystalfontz +:Device Name: Crystalfontz 12864b LCD Series +:Device Code: cfag12864b +:Webpage: http://www.crystalfontz.com +:Device Webpage: http://www.crystalfontz.com/products/12864b/ +:Type: LCD (Liquid Crystal Display) +:Width: 128 +:Height: 64 +:Colors: 2 (B/N) +:Controller: ks0108 +:Controllers: 2 +:Pages: 8 each controller +:Addresses: 64 each page +:Data size: 1 byte each address +:Memory size: 2 * 8 * 64 * 1 = 1024 bytes = 1 Kbyte + + +3. Wiring +--------- + +The cfag12864b LCD Series don't have official wiring. + +The common wiring is done to the parallel port as shown:: + + Parallel Port cfag12864b + + Name Pin# Pin# Name + + Strobe ( 1)------------------------------(17) Enable + Data 0 ( 2)------------------------------( 4) Data 0 + Data 1 ( 3)------------------------------( 5) Data 1 + Data 2 ( 4)------------------------------( 6) Data 2 + Data 3 ( 5)------------------------------( 7) Data 3 + Data 4 ( 6)------------------------------( 8) Data 4 + Data 5 ( 7)------------------------------( 9) Data 5 + Data 6 ( 8)------------------------------(10) Data 6 + Data 7 ( 9)------------------------------(11) Data 7 + (10) [+5v]---( 1) Vdd + (11) [GND]---( 2) Ground + (12) [+5v]---(14) Reset + (13) [GND]---(15) Read / Write + Line (14)------------------------------(13) Controller Select 1 + (15) + Init (16)------------------------------(12) Controller Select 2 + Select (17)------------------------------(16) Data / Instruction + Ground (18)---[GND] [+5v]---(19) LED + + Ground (19)---[GND] + Ground (20)---[GND] E A Values: + Ground (21)---[GND] [GND]---[P1]---(18) Vee - R = Resistor = 22 ohm + Ground (22)---[GND] | - P1 = Preset = 10 Kohm + Ground (23)---[GND] ---- S ------( 3) V0 - P2 = Preset = 1 Kohm + Ground (24)---[GND] | | + Ground (25)---[GND] [GND]---[P2]---[R]---(20) LED - + + +4. Userspace Programming +------------------------ + +The cfag12864bfb describes a framebuffer device (/dev/fbX). + +It has a size of 1024 bytes = 1 Kbyte. +Each bit represents one pixel. If the bit is high, the pixel will +turn on. If the pixel is low, the pixel will turn off. + +You can use the framebuffer as a file: fopen, fwrite, fclose... +Although the LCD won't get updated until the next refresh time arrives. + +Also, you can mmap the framebuffer: open & mmap, munmap & close... +which is the best option for most uses. + +Check samples/auxdisplay/cfag12864b-example.c +for a real working userspace complete program with usage examples. diff --git a/Documentation/admin-guide/auxdisplay/index.rst b/Documentation/admin-guide/auxdisplay/index.rst new file mode 100644 index 000000000000..e466f0595248 --- /dev/null +++ b/Documentation/admin-guide/auxdisplay/index.rst @@ -0,0 +1,16 @@ +========================= +Auxiliary Display Support +========================= + +.. toctree:: + :maxdepth: 1 + + ks0108.rst + cfag12864b.rst + +.. only:: subproject and html + + Indices + ======= + + * :ref:`genindex` diff --git a/Documentation/admin-guide/auxdisplay/ks0108.rst b/Documentation/admin-guide/auxdisplay/ks0108.rst new file mode 100644 index 000000000000..c0b7faf73136 --- /dev/null +++ b/Documentation/admin-guide/auxdisplay/ks0108.rst @@ -0,0 +1,50 @@ +========================================== +ks0108 LCD Controller Driver Documentation +========================================== + +:License: GPLv2 +:Author & Maintainer: Miguel Ojeda Sandonis +:Date: 2006-10-27 + + + +.. INDEX + + 1. DRIVER INFORMATION + 2. DEVICE INFORMATION + 3. WIRING + + +1. Driver Information +--------------------- + +This driver supports the ks0108 LCD controller. + + +2. Device Information +--------------------- + +:Manufacturer: Samsung +:Device Name: KS0108 LCD Controller +:Device Code: ks0108 +:Webpage: - +:Device Webpage: - +:Type: LCD Controller (Liquid Crystal Display Controller) +:Width: 64 +:Height: 64 +:Colors: 2 (B/N) +:Pages: 8 +:Addresses: 64 each page +:Data size: 1 byte each address +:Memory size: 8 * 64 * 1 = 512 bytes + + +3. Wiring +--------- + +The driver supports data parallel port wiring. + +If you aren't building LCD related hardware, you should check +your LCD specific wiring information in the same folder. + +For example, check Documentation/admin-guide/auxdisplay/cfag12864b.rst diff --git a/Documentation/admin-guide/cgroup-v1/blkio-controller.rst b/Documentation/admin-guide/cgroup-v1/blkio-controller.rst index 1d7d962933be..36d43ae7dc13 100644 --- a/Documentation/admin-guide/cgroup-v1/blkio-controller.rst +++ b/Documentation/admin-guide/cgroup-v1/blkio-controller.rst @@ -130,12 +130,6 @@ Proportional weight policy files dev weight 8:16 300 -- blkio.leaf_weight[_device] - - Equivalents of blkio.weight[_device] for the purpose of - deciding how much weight tasks in the given cgroup has while - competing with the cgroup's child cgroups. For details, - please refer to Documentation/block/cfq-iosched.txt. - - blkio.time - disk time allocated to cgroup per device in milliseconds. First two fields specify the major and minor number of the device and diff --git a/Documentation/admin-guide/cgroup-v2.rst b/Documentation/admin-guide/cgroup-v2.rst index 3b29005aa981..0fa8c0e615c2 100644 --- a/Documentation/admin-guide/cgroup-v2.rst +++ b/Documentation/admin-guide/cgroup-v2.rst @@ -951,6 +951,13 @@ controller implements weight and absolute bandwidth limit models for normal scheduling policy and absolute bandwidth allocation model for realtime scheduling policy. +In all the above models, cycles distribution is defined only on a temporal +base and it does not account for the frequency at which tasks are executed. +The (optional) utilization clamping support allows to hint the schedutil +cpufreq governor about the minimum desired frequency which should always be +provided by a CPU, as well as the maximum desired frequency, which should not +be exceeded by a CPU. + WARNING: cgroup2 doesn't yet support control of realtime processes and the cpu controller can only be enabled when all RT processes are in the root cgroup. Be aware that system management software may already @@ -1016,6 +1023,33 @@ All time durations are in microseconds. Shows pressure stall information for CPU. See Documentation/accounting/psi.rst for details. + cpu.uclamp.min + A read-write single value file which exists on non-root cgroups. + The default is "0", i.e. no utilization boosting. + + The requested minimum utilization (protection) as a percentage + rational number, e.g. 12.34 for 12.34%. + + This interface allows reading and setting minimum utilization clamp + values similar to the sched_setattr(2). This minimum utilization + value is used to clamp the task specific minimum utilization clamp. + + The requested minimum utilization (protection) is always capped by + the current value for the maximum utilization (limit), i.e. + `cpu.uclamp.max`. + + cpu.uclamp.max + A read-write single value file which exists on non-root cgroups. + The default is "max". i.e. no utilization capping + + The requested maximum utilization (limit) as a percentage rational + number, e.g. 98.76 for 98.76%. + + This interface allows reading and setting maximum utilization clamp + values similar to the sched_setattr(2). This maximum utilization + value is used to clamp the task specific maximum utilization clamp. + + Memory ------ @@ -1435,6 +1469,103 @@ IO Interface Files 8:16 rbytes=1459200 wbytes=314773504 rios=192 wios=353 dbytes=0 dios=0 8:0 rbytes=90430464 wbytes=299008000 rios=8950 wios=1252 dbytes=50331648 dios=3021 + io.cost.qos + A read-write nested-keyed file with exists only on the root + cgroup. + + This file configures the Quality of Service of the IO cost + model based controller (CONFIG_BLK_CGROUP_IOCOST) which + currently implements "io.weight" proportional control. Lines + are keyed by $MAJ:$MIN device numbers and not ordered. The + line for a given device is populated on the first write for + the device on "io.cost.qos" or "io.cost.model". The following + nested keys are defined. + + ====== ===================================== + enable Weight-based control enable + ctrl "auto" or "user" + rpct Read latency percentile [0, 100] + rlat Read latency threshold + wpct Write latency percentile [0, 100] + wlat Write latency threshold + min Minimum scaling percentage [1, 10000] + max Maximum scaling percentage [1, 10000] + ====== ===================================== + + The controller is disabled by default and can be enabled by + setting "enable" to 1. "rpct" and "wpct" parameters default + to zero and the controller uses internal device saturation + state to adjust the overall IO rate between "min" and "max". + + When a better control quality is needed, latency QoS + parameters can be configured. For example:: + + 8:16 enable=1 ctrl=auto rpct=95.00 rlat=75000 wpct=95.00 wlat=150000 min=50.00 max=150.0 + + shows that on sdb, the controller is enabled, will consider + the device saturated if the 95th percentile of read completion + latencies is above 75ms or write 150ms, and adjust the overall + IO issue rate between 50% and 150% accordingly. + + The lower the saturation point, the better the latency QoS at + the cost of aggregate bandwidth. The narrower the allowed + adjustment range between "min" and "max", the more conformant + to the cost model the IO behavior. Note that the IO issue + base rate may be far off from 100% and setting "min" and "max" + blindly can lead to a significant loss of device capacity or + control quality. "min" and "max" are useful for regulating + devices which show wide temporary behavior changes - e.g. a + ssd which accepts writes at the line speed for a while and + then completely stalls for multiple seconds. + + When "ctrl" is "auto", the parameters are controlled by the + kernel and may change automatically. Setting "ctrl" to "user" + or setting any of the percentile and latency parameters puts + it into "user" mode and disables the automatic changes. The + automatic mode can be restored by setting "ctrl" to "auto". + + io.cost.model + A read-write nested-keyed file with exists only on the root + cgroup. + + This file configures the cost model of the IO cost model based + controller (CONFIG_BLK_CGROUP_IOCOST) which currently + implements "io.weight" proportional control. Lines are keyed + by $MAJ:$MIN device numbers and not ordered. The line for a + given device is populated on the first write for the device on + "io.cost.qos" or "io.cost.model". The following nested keys + are defined. + + ===== ================================ + ctrl "auto" or "user" + model The cost model in use - "linear" + ===== ================================ + + When "ctrl" is "auto", the kernel may change all parameters + dynamically. When "ctrl" is set to "user" or any other + parameters are written to, "ctrl" become "user" and the + automatic changes are disabled. + + When "model" is "linear", the following model parameters are + defined. + + ============= ======================================== + [r|w]bps The maximum sequential IO throughput + [r|w]seqiops The maximum 4k sequential IOs per second + [r|w]randiops The maximum 4k random IOs per second + ============= ======================================== + + From the above, the builtin linear model determines the base + costs of a sequential and random IO and the cost coefficient + for the IO size. While simple, this model can cover most + common device classes acceptably. + + The IO cost model isn't expected to be accurate in absolute + sense and is scaled to the device behavior dynamically. + + If needed, tools/cgroup/iocost_coef_gen.py can be used to + generate device-specific coefficients. + io.weight A read-write flat-keyed file which exists on non-root cgroups. The default is "default 100". diff --git a/Documentation/admin-guide/cifs/authors.rst b/Documentation/admin-guide/cifs/authors.rst new file mode 100644 index 000000000000..b02d6dd6c070 --- /dev/null +++ b/Documentation/admin-guide/cifs/authors.rst @@ -0,0 +1,69 @@ +======= +Authors +======= + +Original Author +--------------- + +Steve French (sfrench@samba.org) + +The author wishes to express his appreciation and thanks to: +Andrew Tridgell (Samba team) for his early suggestions about smb/cifs VFS +improvements. Thanks to IBM for allowing me time and test resources to pursue +this project, to Jim McDonough from IBM (and the Samba Team) for his help, to +the IBM Linux JFS team for explaining many esoteric Linux filesystem features. +Jeremy Allison of the Samba team has done invaluable work in adding the server +side of the original CIFS Unix extensions and reviewing and implementing +portions of the newer CIFS POSIX extensions into the Samba 3 file server. Thank +Dave Boutcher of IBM Rochester (author of the OS/400 smb/cifs filesystem client) +for proving years ago that very good smb/cifs clients could be done on Unix-like +operating systems. Volker Lendecke, Andrew Tridgell, Urban Widmark, John +Newbigin and others for their work on the Linux smbfs module. Thanks to +the other members of the Storage Network Industry Association CIFS Technical +Workgroup for their work specifying this highly complex protocol and finally +thanks to the Samba team for their technical advice and encouragement. + +Patch Contributors +------------------ + +- Zwane Mwaikambo +- Andi Kleen +- Amrut Joshi +- Shobhit Dayal +- Sergey Vlasov +- Richard Hughes +- Yury Umanets +- Mark Hamzy (for some of the early cifs IPv6 work) +- Domen Puncer +- Jesper Juhl (in particular for lots of whitespace/formatting cleanup) +- Vince Negri and Dave Stahl (for finding an important caching bug) +- Adrian Bunk (kcalloc cleanups) +- Miklos Szeredi +- Kazeon team for various fixes especially for 2.4 version. +- Asser Ferno (Change Notify support) +- Shaggy (Dave Kleikamp) for innumerable small fs suggestions and some good cleanup +- Gunter Kukkukk (testing and suggestions for support of old servers) +- Igor Mammedov (DFS support) +- Jeff Layton (many, many fixes, as well as great work on the cifs Kerberos code) +- Scott Lovenberg +- Pavel Shilovsky (for great work adding SMB2 support, and various SMB3 features) +- Aurelien Aptel (for DFS SMB3 work and some key bug fixes) +- Ronnie Sahlberg (for SMB3 xattr work, bug fixes, and lots of great work on compounding) +- Shirish Pargaonkar (for many ACL patches over the years) +- Sachin Prabhu (many bug fixes, including for reconnect, copy offload and security) +- Paulo Alcantara +- Long Li (some great work on RDMA, SMB Direct) + + +Test case and Bug Report contributors +------------------------------------- +Thanks to those in the community who have submitted detailed bug reports +and debug of problems they have found: Jochen Dolze, David Blaine, +Rene Scharfe, Martin Josefsson, Alexander Wild, Anthony Liguori, +Lars Muller, Urban Widmark, Massimiliano Ferrero, Howard Owen, +Olaf Kirch, Kieron Briggs, Nick Millington and others. Also special +mention to the Stanford Checker (SWAT) which pointed out many minor +bugs in error paths. Valuable suggestions also have come from Al Viro +and Dave Miller. + +And thanks to the IBM LTC and Power test teams and SuSE and Citrix and RedHat testers for finding multiple bugs during excellent stress test runs. diff --git a/Documentation/admin-guide/cifs/changes.rst b/Documentation/admin-guide/cifs/changes.rst new file mode 100644 index 000000000000..71f2ecb62299 --- /dev/null +++ b/Documentation/admin-guide/cifs/changes.rst @@ -0,0 +1,8 @@ +======= +Changes +======= + +See https://wiki.samba.org/index.php/LinuxCIFSKernel for summary +information (that may be easier to read than parsing the output of +"git log fs/cifs") about fixes/improvements to CIFS/SMB2/SMB3 support (changes +to cifs.ko module) by kernel version (and cifs internal module version). diff --git a/Documentation/admin-guide/cifs/index.rst b/Documentation/admin-guide/cifs/index.rst new file mode 100644 index 000000000000..fad5268635f5 --- /dev/null +++ b/Documentation/admin-guide/cifs/index.rst @@ -0,0 +1,21 @@ +.. SPDX-License-Identifier: GPL-2.0 + +==== +CIFS +==== + +.. toctree:: + :maxdepth: 2 + + introduction + usage + todo + changes + authors + +.. only:: subproject and html + + Indices + ======= + + * :ref:`genindex` diff --git a/Documentation/admin-guide/cifs/introduction.rst b/Documentation/admin-guide/cifs/introduction.rst new file mode 100644 index 000000000000..0b98f672d36f --- /dev/null +++ b/Documentation/admin-guide/cifs/introduction.rst @@ -0,0 +1,53 @@ +============ +Introduction +============ + + This is the client VFS module for the SMB3 NAS protocol as well + as for older dialects such as the Common Internet File System (CIFS) + protocol which was the successor to the Server Message Block + (SMB) protocol, the native file sharing mechanism for most early + PC operating systems. New and improved versions of CIFS are now + called SMB2 and SMB3. Use of SMB3 (and later, including SMB3.1.1) + is strongly preferred over using older dialects like CIFS due to + security reaasons. All modern dialects, including the most recent, + SMB3.1.1 are supported by the CIFS VFS module. The SMB3 protocol + is implemented and supported by all major file servers + such as all modern versions of Windows (including Windows 2016 + Server), as well as by Samba (which provides excellent + CIFS/SMB2/SMB3 server support and tools for Linux and many other + operating systems). Apple systems also support SMB3 well, as + do most Network Attached Storage vendors, so this network + filesystem client can mount to a wide variety of systems. + It also supports mounting to the cloud (for example + Microsoft Azure), including the necessary security features. + + The intent of this module is to provide the most advanced network + file system function for SMB3 compliant servers, including advanced + security features, excellent parallelized high performance i/o, better + POSIX compliance, secure per-user session establishment, encryption, + high performance safe distributed caching (leases/oplocks), optional packet + signing, large files, Unicode support and other internationalization + improvements. Since both Samba server and this filesystem client support + the CIFS Unix extensions (and in the future SMB3 POSIX extensions), + the combination can provide a reasonable alternative to other network and + cluster file systems for fileserving in some Linux to Linux environments, + not just in Linux to Windows (or Linux to Mac) environments. + + This filesystem has a mount utility (mount.cifs) and various user space + tools (including smbinfo and setcifsacl) that can be obtained from + + https://git.samba.org/?p=cifs-utils.git + + or + + git://git.samba.org/cifs-utils.git + + mount.cifs should be installed in the directory with the other mount helpers. + + For more information on the module see the project wiki page at + + https://wiki.samba.org/index.php/LinuxCIFS + + and + + https://wiki.samba.org/index.php/LinuxCIFS_utils diff --git a/Documentation/admin-guide/cifs/todo.rst b/Documentation/admin-guide/cifs/todo.rst new file mode 100644 index 000000000000..084c25f92dcb --- /dev/null +++ b/Documentation/admin-guide/cifs/todo.rst @@ -0,0 +1,133 @@ +==== +TODO +==== + +Version 2.14 December 21, 2018 + +A Partial List of Missing Features +================================== + +Contributions are welcome. There are plenty of opportunities +for visible, important contributions to this module. Here +is a partial list of the known problems and missing features: + +a) SMB3 (and SMB3.1.1) missing optional features: + + - multichannel (started), integration with RDMA + - directory leases (improved metadata caching), started (root dir only) + - T10 copy offload ie "ODX" (copy chunk, and "Duplicate Extents" ioctl + currently the only two server side copy mechanisms supported) + +b) improved sparse file support (fiemap and SEEK_HOLE are implemented + but additional features would be supportable by the protocol). + +c) Directory entry caching relies on a 1 second timer, rather than + using Directory Leases, currently only the root file handle is cached longer + +d) quota support (needs minor kernel change since quota calls + to make it to network filesystems or deviceless filesystems) + +e) Additional use cases can be optimized to use "compounding" (e.g. + open/query/close and open/setinfo/close) to reduce the number of + roundtrips to the server and improve performance. Various cases + (stat, statfs, create, unlink, mkdir) already have been improved by + using compounding but more can be done. In addition we could + significantly reduce redundant opens by using deferred close (with + handle caching leases) and better using reference counters on file + handles. + +f) Finish inotify support so kde and gnome file list windows + will autorefresh (partially complete by Asser). Needs minor kernel + vfs change to support removing D_NOTIFY on a file. + +g) Add GUI tool to configure /proc/fs/cifs settings and for display of + the CIFS statistics (started) + +h) implement support for security and trusted categories of xattrs + (requires minor protocol extension) to enable better support for SELINUX + +i) Add support for tree connect contexts (see MS-SMB2) a new SMB3.1.1 protocol + feature (may be especially useful for virtualization). + +j) Create UID mapping facility so server UIDs can be mapped on a per + mount or a per server basis to client UIDs or nobody if no mapping + exists. Also better integration with winbind for resolving SID owners + +k) Add tools to take advantage of more smb3 specific ioctls and features + (passthrough ioctl/fsctl is now implemented in cifs.ko to allow + sending various SMB3 fsctls and query info and set info calls + directly from user space) Add tools to make setting various non-POSIX + metadata attributes easier from tools (e.g. extending what was done + in smb-info tool). + +l) encrypted file support + +m) improved stats gathering tools (perhaps integration with nfsometer?) + to extend and make easier to use what is currently in /proc/fs/cifs/Stats + +n) Add support for claims based ACLs ("DAC") + +o) mount helper GUI (to simplify the various configuration options on mount) + +p) Add support for witness protocol (perhaps ioctl to cifs.ko from user space + tool listening on witness protocol RPC) to allow for notification of share + move, server failover, and server adapter changes. And also improve other + failover scenarios, e.g. when client knows multiple DFS entries point to + different servers, and the server we are connected to has gone down. + +q) Allow mount.cifs to be more verbose in reporting errors with dialect + or unsupported feature errors. + +r) updating cifs documentation, and user guide. + +s) Addressing bugs found by running a broader set of xfstests in standard + file system xfstest suite. + +t) split cifs and smb3 support into separate modules so legacy (and less + secure) CIFS dialect can be disabled in environments that don't need it + and simplify the code. + +v) POSIX Extensions for SMB3.1.1 (started, create and mkdir support added + so far). + +w) Add support for additional strong encryption types, and additional spnego + authentication mechanisms (see MS-SMB2) + +x) Finish support for SMB3.1.1 compression + +Known Bugs +========== + +See http://bugzilla.samba.org - search on product "CifsVFS" for +current bug list. Also check http://bugzilla.kernel.org (Product = File System, Component = CIFS) + +1) existing symbolic links (Windows reparse points) are recognized but + can not be created remotely. They are implemented for Samba and those that + support the CIFS Unix extensions, although earlier versions of Samba + overly restrict the pathnames. +2) follow_link and readdir code does not follow dfs junctions + but recognizes them + +Misc testing to do +================== +1) check out max path names and max path name components against various server + types. Try nested symlinks (8 deep). Return max path name in stat -f information + +2) Improve xfstest's cifs/smb3 enablement and adapt xfstests where needed to test + cifs/smb3 better + +3) Additional performance testing and optimization using iozone and similar - + there are some easy changes that can be done to parallelize sequential writes, + and when signing is disabled to request larger read sizes (larger than + negotiated size) and send larger write sizes to modern servers. + +4) More exhaustively test against less common servers + +5) Continue to extend the smb3 "buildbot" which does automated xfstesting + against Windows, Samba and Azure currently - to add additional tests and + to allow the buildbot to execute the tests faster. The URL for the + buildbot is: http://smb3-test-rhel-75.southcentralus.cloudapp.azure.com + +6) Address various coverity warnings (most are not bugs per-se, but + the more warnings are addressed, the easier it is to spot real + problems that static analyzers will point out in the future). diff --git a/Documentation/admin-guide/cifs/usage.rst b/Documentation/admin-guide/cifs/usage.rst new file mode 100644 index 000000000000..d3fb67b8a976 --- /dev/null +++ b/Documentation/admin-guide/cifs/usage.rst @@ -0,0 +1,869 @@ +===== +Usage +===== + +This module supports the SMB3 family of advanced network protocols (as well +as older dialects, originally called "CIFS" or SMB1). + +The CIFS VFS module for Linux supports many advanced network filesystem +features such as hierarchical DFS like namespace, hardlinks, locking and more. +It was designed to comply with the SNIA CIFS Technical Reference (which +supersedes the 1992 X/Open SMB Standard) as well as to perform best practice +practical interoperability with Windows 2000, Windows XP, Samba and equivalent +servers. This code was developed in participation with the Protocol Freedom +Information Foundation. CIFS and now SMB3 has now become a defacto +standard for interoperating between Macs and Windows and major NAS appliances. + +Please see +MS-SMB2 (for detailed SMB2/SMB3/SMB3.1.1 protocol specification) +http://protocolfreedom.org/ and +http://samba.org/samba/PFIF/ +for more details. + + +For questions or bug reports please contact: + + smfrench@gmail.com + +See the project page at: https://wiki.samba.org/index.php/LinuxCIFS_utils + +Build instructions +================== + +For Linux: + +1) Download the kernel (e.g. from http://www.kernel.org) + and change directory into the top of the kernel directory tree + (e.g. /usr/src/linux-2.5.73) +2) make menuconfig (or make xconfig) +3) select cifs from within the network filesystem choices +4) save and exit +5) make + + +Installation instructions +========================= + +If you have built the CIFS vfs as module (successfully) simply +type ``make modules_install`` (or if you prefer, manually copy the file to +the modules directory e.g. /lib/modules/2.4.10-4GB/kernel/fs/cifs/cifs.ko). + +If you have built the CIFS vfs into the kernel itself, follow the instructions +for your distribution on how to install a new kernel (usually you +would simply type ``make install``). + +If you do not have the utility mount.cifs (in the Samba 4.x source tree and on +the CIFS VFS web site) copy it to the same directory in which mount helpers +reside (usually /sbin). Although the helper software is not +required, mount.cifs is recommended. Most distros include a ``cifs-utils`` +package that includes this utility so it is recommended to install this. + +Note that running the Winbind pam/nss module (logon service) on all of your +Linux clients is useful in mapping Uids and Gids consistently across the +domain to the proper network user. The mount.cifs mount helper can be +found at cifs-utils.git on git.samba.org + +If cifs is built as a module, then the size and number of network buffers +and maximum number of simultaneous requests to one server can be configured. +Changing these from their defaults is not recommended. By executing modinfo:: + + modinfo kernel/fs/cifs/cifs.ko + +on kernel/fs/cifs/cifs.ko the list of configuration changes that can be made +at module initialization time (by running insmod cifs.ko) can be seen. + +Recommendations +=============== + +To improve security the SMB2.1 dialect or later (usually will get SMB3) is now +the new default. To use old dialects (e.g. to mount Windows XP) use "vers=1.0" +on mount (or vers=2.0 for Windows Vista). Note that the CIFS (vers=1.0) is +much older and less secure than the default dialect SMB3 which includes +many advanced security features such as downgrade attack detection +and encrypted shares and stronger signing and authentication algorithms. +There are additional mount options that may be helpful for SMB3 to get +improved POSIX behavior (NB: can use vers=3.0 to force only SMB3, never 2.1): + + ``mfsymlinks`` and ``cifsacl`` and ``idsfromsid`` + +Allowing User Mounts +==================== + +To permit users to mount and unmount over directories they own is possible +with the cifs vfs. A way to enable such mounting is to mark the mount.cifs +utility as suid (e.g. ``chmod +s /sbin/mount.cifs``). To enable users to +umount shares they mount requires + +1) mount.cifs version 1.4 or later +2) an entry for the share in /etc/fstab indicating that a user may + unmount it e.g.:: + + //server/usersharename /mnt/username cifs user 0 0 + +Note that when the mount.cifs utility is run suid (allowing user mounts), +in order to reduce risks, the ``nosuid`` mount flag is passed in on mount to +disallow execution of an suid program mounted on the remote target. +When mount is executed as root, nosuid is not passed in by default, +and execution of suid programs on the remote target would be enabled +by default. This can be changed, as with nfs and other filesystems, +by simply specifying ``nosuid`` among the mount options. For user mounts +though to be able to pass the suid flag to mount requires rebuilding +mount.cifs with the following flag: CIFS_ALLOW_USR_SUID + +There is a corresponding manual page for cifs mounting in the Samba 3.0 and +later source tree in docs/manpages/mount.cifs.8 + +Allowing User Unmounts +====================== + +To permit users to ummount directories that they have user mounted (see above), +the utility umount.cifs may be used. It may be invoked directly, or if +umount.cifs is placed in /sbin, umount can invoke the cifs umount helper +(at least for most versions of the umount utility) for umount of cifs +mounts, unless umount is invoked with -i (which will avoid invoking a umount +helper). As with mount.cifs, to enable user unmounts umount.cifs must be marked +as suid (e.g. ``chmod +s /sbin/umount.cifs``) or equivalent (some distributions +allow adding entries to a file to the /etc/permissions file to achieve the +equivalent suid effect). For this utility to succeed the target path +must be a cifs mount, and the uid of the current user must match the uid +of the user who mounted the resource. + +Also note that the customary way of allowing user mounts and unmounts is +(instead of using mount.cifs and unmount.cifs as suid) to add a line +to the file /etc/fstab for each //server/share you wish to mount, but +this can become unwieldy when potential mount targets include many +or unpredictable UNC names. + +Samba Considerations +==================== + +Most current servers support SMB2.1 and SMB3 which are more secure, +but there are useful protocol extensions for the older less secure CIFS +dialect, so to get the maximum benefit if mounting using the older dialect +(CIFS/SMB1), we recommend using a server that supports the SNIA CIFS +Unix Extensions standard (e.g. almost any version of Samba ie version +2.2.5 or later) but the CIFS vfs works fine with a wide variety of CIFS servers. +Note that uid, gid and file permissions will display default values if you do +not have a server that supports the Unix extensions for CIFS (such as Samba +2.2.5 or later). To enable the Unix CIFS Extensions in the Samba server, add +the line:: + + unix extensions = yes + +to your smb.conf file on the server. Note that the following smb.conf settings +are also useful (on the Samba server) when the majority of clients are Unix or +Linux:: + + case sensitive = yes + delete readonly = yes + ea support = yes + +Note that server ea support is required for supporting xattrs from the Linux +cifs client, and that EA support is present in later versions of Samba (e.g. +3.0.6 and later (also EA support works in all versions of Windows, at least to +shares on NTFS filesystems). Extended Attribute (xattr) support is an optional +feature of most Linux filesystems which may require enabling via +make menuconfig. Client support for extended attributes (user xattr) can be +disabled on a per-mount basis by specifying ``nouser_xattr`` on mount. + +The CIFS client can get and set POSIX ACLs (getfacl, setfacl) to Samba servers +version 3.10 and later. Setting POSIX ACLs requires enabling both XATTR and +then POSIX support in the CIFS configuration options when building the cifs +module. POSIX ACL support can be disabled on a per mount basic by specifying +``noacl`` on mount. + +Some administrators may want to change Samba's smb.conf ``map archive`` and +``create mask`` parameters from the default. Unless the create mask is changed +newly created files can end up with an unnecessarily restrictive default mode, +which may not be what you want, although if the CIFS Unix extensions are +enabled on the server and client, subsequent setattr calls (e.g. chmod) can +fix the mode. Note that creating special devices (mknod) remotely +may require specifying a mkdev function to Samba if you are not using +Samba 3.0.6 or later. For more information on these see the manual pages +(``man smb.conf``) on the Samba server system. Note that the cifs vfs, +unlike the smbfs vfs, does not read the smb.conf on the client system +(the few optional settings are passed in on mount via -o parameters instead). +Note that Samba 2.2.7 or later includes a fix that allows the CIFS VFS to delete +open files (required for strict POSIX compliance). Windows Servers already +supported this feature. Samba server does not allow symlinks that refer to files +outside of the share, so in Samba versions prior to 3.0.6, most symlinks to +files with absolute paths (ie beginning with slash) such as:: + + ln -s /mnt/foo bar + +would be forbidden. Samba 3.0.6 server or later includes the ability to create +such symlinks safely by converting unsafe symlinks (ie symlinks to server +files that are outside of the share) to a samba specific format on the server +that is ignored by local server applications and non-cifs clients and that will +not be traversed by the Samba server). This is opaque to the Linux client +application using the cifs vfs. Absolute symlinks will work to Samba 3.0.5 or +later, but only for remote clients using the CIFS Unix extensions, and will +be invisbile to Windows clients and typically will not affect local +applications running on the same server as Samba. + +Use instructions +================ + +Once the CIFS VFS support is built into the kernel or installed as a module +(cifs.ko), you can use mount syntax like the following to access Samba or +Mac or Windows servers:: + + mount -t cifs //9.53.216.11/e$ /mnt -o username=myname,password=mypassword + +Before -o the option -v may be specified to make the mount.cifs +mount helper display the mount steps more verbosely. +After -o the following commonly used cifs vfs specific options +are supported:: + + username=<username> + password=<password> + domain=<domain name> + +Other cifs mount options are described below. Use of TCP names (in addition to +ip addresses) is available if the mount helper (mount.cifs) is installed. If +you do not trust the server to which are mounted, or if you do not have +cifs signing enabled (and the physical network is insecure), consider use +of the standard mount options ``noexec`` and ``nosuid`` to reduce the risk of +running an altered binary on your local system (downloaded from a hostile server +or altered by a hostile router). + +Although mounting using format corresponding to the CIFS URL specification is +not possible in mount.cifs yet, it is possible to use an alternate format +for the server and sharename (which is somewhat similar to NFS style mount +syntax) instead of the more widely used UNC format (i.e. \\server\share):: + + mount -t cifs tcp_name_of_server:share_name /mnt -o user=myname,pass=mypasswd + +When using the mount helper mount.cifs, passwords may be specified via alternate +mechanisms, instead of specifying it after -o using the normal ``pass=`` syntax +on the command line: +1) By including it in a credential file. Specify credentials=filename as one +of the mount options. Credential files contain two lines:: + + username=someuser + password=your_password + +2) By specifying the password in the PASSWD environment variable (similarly + the user name can be taken from the USER environment variable). +3) By specifying the password in a file by name via PASSWD_FILE +4) By specifying the password in a file by file descriptor via PASSWD_FD + +If no password is provided, mount.cifs will prompt for password entry + +Restrictions +============ + +Servers must support either "pure-TCP" (port 445 TCP/IP CIFS connections) or RFC +1001/1002 support for "Netbios-Over-TCP/IP." This is not likely to be a +problem as most servers support this. + +Valid filenames differ between Windows and Linux. Windows typically restricts +filenames which contain certain reserved characters (e.g.the character : +which is used to delimit the beginning of a stream name by Windows), while +Linux allows a slightly wider set of valid characters in filenames. Windows +servers can remap such characters when an explicit mapping is specified in +the Server's registry. Samba starting with version 3.10 will allow such +filenames (ie those which contain valid Linux characters, which normally +would be forbidden for Windows/CIFS semantics) as long as the server is +configured for Unix Extensions (and the client has not disabled +/proc/fs/cifs/LinuxExtensionsEnabled). In addition the mount option +``mapposix`` can be used on CIFS (vers=1.0) to force the mapping of +illegal Windows/NTFS/SMB characters to a remap range (this mount parm +is the default for SMB3). This remap (``mapposix``) range is also +compatible with Mac (and "Services for Mac" on some older Windows). + +CIFS VFS Mount Options +====================== +A partial list of the supported mount options follows: + + username + The user name to use when trying to establish + the CIFS session. + password + The user password. If the mount helper is + installed, the user will be prompted for password + if not supplied. + ip + The ip address of the target server + unc + The target server Universal Network Name (export) to + mount. + domain + Set the SMB/CIFS workgroup name prepended to the + username during CIFS session establishment + forceuid + Set the default uid for inodes to the uid + passed in on mount. For mounts to servers + which do support the CIFS Unix extensions, such as a + properly configured Samba server, the server provides + the uid, gid and mode so this parameter should not be + specified unless the server and clients uid and gid + numbering differ. If the server and client are in the + same domain (e.g. running winbind or nss_ldap) and + the server supports the Unix Extensions then the uid + and gid can be retrieved from the server (and uid + and gid would not have to be specified on the mount. + For servers which do not support the CIFS Unix + extensions, the default uid (and gid) returned on lookup + of existing files will be the uid (gid) of the person + who executed the mount (root, except when mount.cifs + is configured setuid for user mounts) unless the ``uid=`` + (gid) mount option is specified. Also note that permission + checks (authorization checks) on accesses to a file occur + at the server, but there are cases in which an administrator + may want to restrict at the client as well. For those + servers which do not report a uid/gid owner + (such as Windows), permissions can also be checked at the + client, and a crude form of client side permission checking + can be enabled by specifying file_mode and dir_mode on + the client. (default) + forcegid + (similar to above but for the groupid instead of uid) (default) + noforceuid + Fill in file owner information (uid) by requesting it from + the server if possible. With this option, the value given in + the uid= option (on mount) will only be used if the server + can not support returning uids on inodes. + noforcegid + (similar to above but for the group owner, gid, instead of uid) + uid + Set the default uid for inodes, and indicate to the + cifs kernel driver which local user mounted. If the server + supports the unix extensions the default uid is + not used to fill in the owner fields of inodes (files) + unless the ``forceuid`` parameter is specified. + gid + Set the default gid for inodes (similar to above). + file_mode + If CIFS Unix extensions are not supported by the server + this overrides the default mode for file inodes. + fsc + Enable local disk caching using FS-Cache (off by default). This + option could be useful to improve performance on a slow link, + heavily loaded server and/or network where reading from the + disk is faster than reading from the server (over the network). + This could also impact scalability positively as the + number of calls to the server are reduced. However, local + caching is not suitable for all workloads for e.g. read-once + type workloads. So, you need to consider carefully your + workload/scenario before using this option. Currently, local + disk caching is functional for CIFS files opened as read-only. + dir_mode + If CIFS Unix extensions are not supported by the server + this overrides the default mode for directory inodes. + port + attempt to contact the server on this tcp port, before + trying the usual ports (port 445, then 139). + iocharset + Codepage used to convert local path names to and from + Unicode. Unicode is used by default for network path + names if the server supports it. If iocharset is + not specified then the nls_default specified + during the local client kernel build will be used. + If server does not support Unicode, this parameter is + unused. + rsize + default read size (usually 16K). The client currently + can not use rsize larger than CIFSMaxBufSize. CIFSMaxBufSize + defaults to 16K and may be changed (from 8K to the maximum + kmalloc size allowed by your kernel) at module install time + for cifs.ko. Setting CIFSMaxBufSize to a very large value + will cause cifs to use more memory and may reduce performance + in some cases. To use rsize greater than 127K (the original + cifs protocol maximum) also requires that the server support + a new Unix Capability flag (for very large read) which some + newer servers (e.g. Samba 3.0.26 or later) do. rsize can be + set from a minimum of 2048 to a maximum of 130048 (127K or + CIFSMaxBufSize, whichever is smaller) + wsize + default write size (default 57344) + maximum wsize currently allowed by CIFS is 57344 (fourteen + 4096 byte pages) + actimeo=n + attribute cache timeout in seconds (default 1 second). + After this timeout, the cifs client requests fresh attribute + information from the server. This option allows to tune the + attribute cache timeout to suit the workload needs. Shorter + timeouts mean better the cache coherency, but increased number + of calls to the server. Longer timeouts mean reduced number + of calls to the server at the expense of less stricter cache + coherency checks (i.e. incorrect attribute cache for a short + period of time). + rw + mount the network share read-write (note that the + server may still consider the share read-only) + ro + mount network share read-only + version + used to distinguish different versions of the + mount helper utility (not typically needed) + sep + if first mount option (after the -o), overrides + the comma as the separator between the mount + parms. e.g.:: + + -o user=myname,password=mypassword,domain=mydom + + could be passed instead with period as the separator by:: + + -o sep=.user=myname.password=mypassword.domain=mydom + + this might be useful when comma is contained within username + or password or domain. This option is less important + when the cifs mount helper cifs.mount (version 1.1 or later) + is used. + nosuid + Do not allow remote executables with the suid bit + program to be executed. This is only meaningful for mounts + to servers such as Samba which support the CIFS Unix Extensions. + If you do not trust the servers in your network (your mount + targets) it is recommended that you specify this option for + greater security. + exec + Permit execution of binaries on the mount. + noexec + Do not permit execution of binaries on the mount. + dev + Recognize block devices on the remote mount. + nodev + Do not recognize devices on the remote mount. + suid + Allow remote files on this mountpoint with suid enabled to + be executed (default for mounts when executed as root, + nosuid is default for user mounts). + credentials + Although ignored by the cifs kernel component, it is used by + the mount helper, mount.cifs. When mount.cifs is installed it + opens and reads the credential file specified in order + to obtain the userid and password arguments which are passed to + the cifs vfs. + guest + Although ignored by the kernel component, the mount.cifs + mount helper will not prompt the user for a password + if guest is specified on the mount options. If no + password is specified a null password will be used. + perm + Client does permission checks (vfs_permission check of uid + and gid of the file against the mode and desired operation), + Note that this is in addition to the normal ACL check on the + target machine done by the server software. + Client permission checking is enabled by default. + noperm + Client does not do permission checks. This can expose + files on this mount to access by other users on the local + client system. It is typically only needed when the server + supports the CIFS Unix Extensions but the UIDs/GIDs on the + client and server system do not match closely enough to allow + access by the user doing the mount, but it may be useful with + non CIFS Unix Extension mounts for cases in which the default + mode is specified on the mount but is not to be enforced on the + client (e.g. perhaps when MultiUserMount is enabled) + Note that this does not affect the normal ACL check on the + target machine done by the server software (of the server + ACL against the user name provided at mount time). + serverino + Use server's inode numbers instead of generating automatically + incrementing inode numbers on the client. Although this will + make it easier to spot hardlinked files (as they will have + the same inode numbers) and inode numbers may be persistent, + note that the server does not guarantee that the inode numbers + are unique if multiple server side mounts are exported under a + single share (since inode numbers on the servers might not + be unique if multiple filesystems are mounted under the same + shared higher level directory). Note that some older + (e.g. pre-Windows 2000) do not support returning UniqueIDs + or the CIFS Unix Extensions equivalent and for those + this mount option will have no effect. Exporting cifs mounts + under nfsd requires this mount option on the cifs mount. + This is now the default if server supports the + required network operation. + noserverino + Client generates inode numbers (rather than using the actual one + from the server). These inode numbers will vary after + unmount or reboot which can confuse some applications, + but not all server filesystems support unique inode + numbers. + setuids + If the CIFS Unix extensions are negotiated with the server + the client will attempt to set the effective uid and gid of + the local process on newly created files, directories, and + devices (create, mkdir, mknod). If the CIFS Unix Extensions + are not negotiated, for newly created files and directories + instead of using the default uid and gid specified on + the mount, cache the new file's uid and gid locally which means + that the uid for the file can change when the inode is + reloaded (or the user remounts the share). + nosetuids + The client will not attempt to set the uid and gid on + on newly created files, directories, and devices (create, + mkdir, mknod) which will result in the server setting the + uid and gid to the default (usually the server uid of the + user who mounted the share). Letting the server (rather than + the client) set the uid and gid is the default. If the CIFS + Unix Extensions are not negotiated then the uid and gid for + new files will appear to be the uid (gid) of the mounter or the + uid (gid) parameter specified on the mount. + netbiosname + When mounting to servers via port 139, specifies the RFC1001 + source name to use to represent the client netbios machine + name when doing the RFC1001 netbios session initialize. + direct + Do not do inode data caching on files opened on this mount. + This precludes mmapping files on this mount. In some cases + with fast networks and little or no caching benefits on the + client (e.g. when the application is doing large sequential + reads bigger than page size without rereading the same data) + this can provide better performance than the default + behavior which caches reads (readahead) and writes + (writebehind) through the local Linux client pagecache + if oplock (caching token) is granted and held. Note that + direct allows write operations larger than page size + to be sent to the server. + strictcache + Use for switching on strict cache mode. In this mode the + client read from the cache all the time it has Oplock Level II, + otherwise - read from the server. All written data are stored + in the cache, but if the client doesn't have Exclusive Oplock, + it writes the data to the server. + rwpidforward + Forward pid of a process who opened a file to any read or write + operation on that file. This prevent applications like WINE + from failing on read and write if we use mandatory brlock style. + acl + Allow setfacl and getfacl to manage posix ACLs if server + supports them. (default) + noacl + Do not allow setfacl and getfacl calls on this mount + user_xattr + Allow getting and setting user xattrs (those attributes whose + name begins with ``user.`` or ``os2.``) as OS/2 EAs (extended + attributes) to the server. This allows support of the + setfattr and getfattr utilities. (default) + nouser_xattr + Do not allow getfattr/setfattr to get/set/list xattrs + mapchars + Translate six of the seven reserved characters (not backslash):: + + *?<>|: + + to the remap range (above 0xF000), which also + allows the CIFS client to recognize files created with + such characters by Windows's POSIX emulation. This can + also be useful when mounting to most versions of Samba + (which also forbids creating and opening files + whose names contain any of these seven characters). + This has no effect if the server does not support + Unicode on the wire. + nomapchars + Do not translate any of these seven characters (default). + nocase + Request case insensitive path name matching (case + sensitive is the default if the server supports it). + (mount option ``ignorecase`` is identical to ``nocase``) + posixpaths + If CIFS Unix extensions are supported, attempt to + negotiate posix path name support which allows certain + characters forbidden in typical CIFS filenames, without + requiring remapping. (default) + noposixpaths + If CIFS Unix extensions are supported, do not request + posix path name support (this may cause servers to + reject creatingfile with certain reserved characters). + nounix + Disable the CIFS Unix Extensions for this mount (tree + connection). This is rarely needed, but it may be useful + in order to turn off multiple settings all at once (ie + posix acls, posix locks, posix paths, symlink support + and retrieving uids/gids/mode from the server) or to + work around a bug in server which implement the Unix + Extensions. + nobrl + Do not send byte range lock requests to the server. + This is necessary for certain applications that break + with cifs style mandatory byte range locks (and most + cifs servers do not yet support requesting advisory + byte range locks). + forcemandatorylock + Even if the server supports posix (advisory) byte range + locking, send only mandatory lock requests. For some + (presumably rare) applications, originally coded for + DOS/Windows, which require Windows style mandatory byte range + locking, they may be able to take advantage of this option, + forcing the cifs client to only send mandatory locks + even if the cifs server would support posix advisory locks. + ``forcemand`` is accepted as a shorter form of this mount + option. + nostrictsync + If this mount option is set, when an application does an + fsync call then the cifs client does not send an SMB Flush + to the server (to force the server to write all dirty data + for this file immediately to disk), although cifs still sends + all dirty (cached) file data to the server and waits for the + server to respond to the write. Since SMB Flush can be + very slow, and some servers may be reliable enough (to risk + delaying slightly flushing the data to disk on the server), + turning on this option may be useful to improve performance for + applications that fsync too much, at a small risk of server + crash. If this mount option is not set, by default cifs will + send an SMB flush request (and wait for a response) on every + fsync call. + nodfs + Disable DFS (global name space support) even if the + server claims to support it. This can help work around + a problem with parsing of DFS paths with Samba server + versions 3.0.24 and 3.0.25. + remount + remount the share (often used to change from ro to rw mounts + or vice versa) + cifsacl + Report mode bits (e.g. on stat) based on the Windows ACL for + the file. (EXPERIMENTAL) + servern + Specify the server 's netbios name (RFC1001 name) to use + when attempting to setup a session to the server. + This is needed for mounting to some older servers (such + as OS/2 or Windows 98 and Windows ME) since they do not + support a default server name. A server name can be up + to 15 characters long and is usually uppercased. + sfu + When the CIFS Unix Extensions are not negotiated, attempt to + create device files and fifos in a format compatible with + Services for Unix (SFU). In addition retrieve bits 10-12 + of the mode via the SETFILEBITS extended attribute (as + SFU does). In the future the bottom 9 bits of the + mode also will be emulated using queries of the security + descriptor (ACL). + mfsymlinks + Enable support for Minshall+French symlinks + (see http://wiki.samba.org/index.php/UNIX_Extensions#Minshall.2BFrench_symlinks) + This option is ignored when specified together with the + 'sfu' option. Minshall+French symlinks are used even if + the server supports the CIFS Unix Extensions. + sign + Must use packet signing (helps avoid unwanted data modification + by intermediate systems in the route). Note that signing + does not work with lanman or plaintext authentication. + seal + Must seal (encrypt) all data on this mounted share before + sending on the network. Requires support for Unix Extensions. + Note that this differs from the sign mount option in that it + causes encryption of data sent over this mounted share but other + shares mounted to the same server are unaffected. + locallease + This option is rarely needed. Fcntl F_SETLEASE is + used by some applications such as Samba and NFSv4 server to + check to see whether a file is cacheable. CIFS has no way + to explicitly request a lease, but can check whether a file + is cacheable (oplocked). Unfortunately, even if a file + is not oplocked, it could still be cacheable (ie cifs client + could grant fcntl leases if no other local processes are using + the file) for cases for example such as when the server does not + support oplocks and the user is sure that the only updates to + the file will be from this client. Specifying this mount option + will allow the cifs client to check for leases (only) locally + for files which are not oplocked instead of denying leases + in that case. (EXPERIMENTAL) + sec + Security mode. Allowed values are: + + none + attempt to connection as a null user (no name) + krb5 + Use Kerberos version 5 authentication + krb5i + Use Kerberos authentication and packet signing + ntlm + Use NTLM password hashing (default) + ntlmi + Use NTLM password hashing with signing (if + /proc/fs/cifs/PacketSigningEnabled on or if + server requires signing also can be the default) + ntlmv2 + Use NTLMv2 password hashing + ntlmv2i + Use NTLMv2 password hashing with packet signing + lanman + (if configured in kernel config) use older + lanman hash + hard + Retry file operations if server is not responding + soft + Limit retries to unresponsive servers (usually only + one retry) before returning an error. (default) + +The mount.cifs mount helper also accepts a few mount options before -o +including: + +=============== =============================================================== + -S take password from stdin (equivalent to setting the environment + variable ``PASSWD_FD=0`` + -V print mount.cifs version + -? display simple usage information +=============== =============================================================== + +With most 2.6 kernel versions of modutils, the version of the cifs kernel +module can be displayed via modinfo. + +Misc /proc/fs/cifs Flags and Debug Info +======================================= + +Informational pseudo-files: + +======================= ======================================================= +DebugData Displays information about active CIFS sessions and + shares, features enabled as well as the cifs.ko + version. +Stats Lists summary resource usage information as well as per + share statistics. +======================= ======================================================= + +Configuration pseudo-files: + +======================= ======================================================= +SecurityFlags Flags which control security negotiation and + also packet signing. Authentication (may/must) + flags (e.g. for NTLM and/or NTLMv2) may be combined with + the signing flags. Specifying two different password + hashing mechanisms (as "must use") on the other hand + does not make much sense. Default flags are:: + + 0x07007 + + (NTLM, NTLMv2 and packet signing allowed). The maximum + allowable flags if you want to allow mounts to servers + using weaker password hashes is 0x37037 (lanman, + plaintext, ntlm, ntlmv2, signing allowed). Some + SecurityFlags require the corresponding menuconfig + options to be enabled (lanman and plaintext require + CONFIG_CIFS_WEAK_PW_HASH for example). Enabling + plaintext authentication currently requires also + enabling lanman authentication in the security flags + because the cifs module only supports sending + laintext passwords using the older lanman dialect + form of the session setup SMB. (e.g. for authentication + using plain text passwords, set the SecurityFlags + to 0x30030):: + + may use packet signing 0x00001 + must use packet signing 0x01001 + may use NTLM (most common password hash) 0x00002 + must use NTLM 0x02002 + may use NTLMv2 0x00004 + must use NTLMv2 0x04004 + may use Kerberos security 0x00008 + must use Kerberos 0x08008 + may use lanman (weak) password hash 0x00010 + must use lanman password hash 0x10010 + may use plaintext passwords 0x00020 + must use plaintext passwords 0x20020 + (reserved for future packet encryption) 0x00040 + +cifsFYI If set to non-zero value, additional debug information + will be logged to the system error log. This field + contains three flags controlling different classes of + debugging entries. The maximum value it can be set + to is 7 which enables all debugging points (default 0). + Some debugging statements are not compiled into the + cifs kernel unless CONFIG_CIFS_DEBUG2 is enabled in the + kernel configuration. cifsFYI may be set to one or + nore of the following flags (7 sets them all):: + + +-----------------------------------------------+------+ + | log cifs informational messages | 0x01 | + +-----------------------------------------------+------+ + | log return codes from cifs entry points | 0x02 | + +-----------------------------------------------+------+ + | log slow responses | 0x04 | + | (ie which take longer than 1 second) | | + | | | + | CONFIG_CIFS_STATS2 must be enabled in .config | | + +-----------------------------------------------+------+ + +traceSMB If set to one, debug information is logged to the + system error log with the start of smb requests + and responses (default 0) +LookupCacheEnable If set to one, inode information is kept cached + for one second improving performance of lookups + (default 1) +LinuxExtensionsEnabled If set to one then the client will attempt to + use the CIFS "UNIX" extensions which are optional + protocol enhancements that allow CIFS servers + to return accurate UID/GID information as well + as support symbolic links. If you use servers + such as Samba that support the CIFS Unix + extensions but do not want to use symbolic link + support and want to map the uid and gid fields + to values supplied at mount (rather than the + actual values, then set this to zero. (default 1) +======================= ======================================================= + +These experimental features and tracing can be enabled by changing flags in +/proc/fs/cifs (after the cifs module has been installed or built into the +kernel, e.g. insmod cifs). To enable a feature set it to 1 e.g. to enable +tracing to the kernel message log type:: + + echo 7 > /proc/fs/cifs/cifsFYI + +cifsFYI functions as a bit mask. Setting it to 1 enables additional kernel +logging of various informational messages. 2 enables logging of non-zero +SMB return codes while 4 enables logging of requests that take longer +than one second to complete (except for byte range lock requests). +Setting it to 4 requires CONFIG_CIFS_STATS2 to be set in kernel configuration +(.config). Setting it to seven enables all three. Finally, tracing +the start of smb requests and responses can be enabled via:: + + echo 1 > /proc/fs/cifs/traceSMB + +Per share (per client mount) statistics are available in /proc/fs/cifs/Stats. +Additional information is available if CONFIG_CIFS_STATS2 is enabled in the +kernel configuration (.config). The statistics returned include counters which +represent the number of attempted and failed (ie non-zero return code from the +server) SMB3 (or cifs) requests grouped by request type (read, write, close etc.). +Also recorded is the total bytes read and bytes written to the server for +that share. Note that due to client caching effects this can be less than the +number of bytes read and written by the application running on the client. +Statistics can be reset to zero by ``echo 0 > /proc/fs/cifs/Stats`` which may be +useful if comparing performance of two different scenarios. + +Also note that ``cat /proc/fs/cifs/DebugData`` will display information about +the active sessions and the shares that are mounted. + +Enabling Kerberos (extended security) works but requires version 1.2 or later +of the helper program cifs.upcall to be present and to be configured in the +/etc/request-key.conf file. The cifs.upcall helper program is from the Samba +project(http://www.samba.org). NTLM and NTLMv2 and LANMAN support do not +require this helper. Note that NTLMv2 security (which does not require the +cifs.upcall helper program), instead of using Kerberos, is sufficient for +some use cases. + +DFS support allows transparent redirection to shares in an MS-DFS name space. +In addition, DFS support for target shares which are specified as UNC +names which begin with host names (rather than IP addresses) requires +a user space helper (such as cifs.upcall) to be present in order to +translate host names to ip address, and the user space helper must also +be configured in the file /etc/request-key.conf. Samba, Windows servers and +many NAS appliances support DFS as a way of constructing a global name +space to ease network configuration and improve reliability. + +To use cifs Kerberos and DFS support, the Linux keyutils package should be +installed and something like the following lines should be added to the +/etc/request-key.conf file:: + + create cifs.spnego * * /usr/local/sbin/cifs.upcall %k + create dns_resolver * * /usr/local/sbin/cifs.upcall %k + +CIFS kernel module parameters +============================= +These module parameters can be specified or modified either during the time of +module loading or during the runtime by using the interface:: + + /proc/module/cifs/parameters/<param> + +i.e.:: + + echo "value" > /sys/module/cifs/parameters/<param> + +================= ========================================================== +1. enable_oplocks Enable or disable oplocks. Oplocks are enabled by default. + [Y/y/1]. To disable use any of [N/n/0]. +================= ========================================================== diff --git a/Documentation/admin-guide/cifs/winucase_convert.pl b/Documentation/admin-guide/cifs/winucase_convert.pl new file mode 100755 index 000000000000..322a9c833f23 --- /dev/null +++ b/Documentation/admin-guide/cifs/winucase_convert.pl @@ -0,0 +1,62 @@ +#!/usr/bin/perl -w +# +# winucase_convert.pl -- convert "Windows 8 Upper Case Mapping Table.txt" to +# a two-level set of C arrays. +# +# Copyright 2013: Jeff Layton <jlayton@redhat.com> +# +# This program is free software: you can redistribute it and/or modify +# it under the terms of the GNU General Public License as published by +# the Free Software Foundation, either version 3 of the License, or +# (at your option) any later version. +# +# This program is distributed in the hope that it will be useful, +# but WITHOUT ANY WARRANTY; without even the implied warranty of +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +# GNU General Public License for more details. +# +# You should have received a copy of the GNU General Public License +# along with this program. If not, see <http://www.gnu.org/licenses/>. +# + +while(<>) { + next if (!/^0x(..)(..)\t0x(....)\t/); + $firstchar = hex($1); + $secondchar = hex($2); + $uppercase = hex($3); + + $top[$firstchar][$secondchar] = $uppercase; +} + +for ($i = 0; $i < 256; $i++) { + next if (!$top[$i]); + + printf("static const wchar_t t2_%2.2x[256] = {", $i); + for ($j = 0; $j < 256; $j++) { + if (($j % 8) == 0) { + print "\n\t"; + } else { + print " "; + } + printf("0x%4.4x,", $top[$i][$j] ? $top[$i][$j] : 0); + } + print "\n};\n\n"; +} + +printf("static const wchar_t *const toplevel[256] = {", $i); +for ($i = 0; $i < 256; $i++) { + if (($i % 8) == 0) { + print "\n\t"; + } elsif ($top[$i]) { + print " "; + } else { + print " "; + } + + if ($top[$i]) { + printf("t2_%2.2x,", $i); + } else { + print "NULL,"; + } +} +print "\n};\n\n"; diff --git a/Documentation/admin-guide/devices.txt b/Documentation/admin-guide/devices.txt index e56e00655153..1c5d2281efc9 100644 --- a/Documentation/admin-guide/devices.txt +++ b/Documentation/admin-guide/devices.txt @@ -1647,8 +1647,17 @@ 0 = /dev/comedi0 First comedi device 1 = /dev/comedi1 Second comedi device ... + 47 = /dev/comedi47 48th comedi device - See http://stm.lbl.gov/comedi. + Minors 48 to 255 are reserved for comedi subdevices with + pathnames of the form "/dev/comediX_subdY", where "X" is the + minor number of the associated comedi device and "Y" is the + subdevice number. These subdevice minors are assigned + dynamically, so there is no fixed mapping from subdevice + pathnames to minor numbers. + + See http://www.comedi.org/ for information about the Comedi + project. 98 block User-mode virtual block device 0 = /dev/ubda First user-mode block device diff --git a/Documentation/admin-guide/hw-vuln/spectre.rst b/Documentation/admin-guide/hw-vuln/spectre.rst index 25f3b2532198..e05e581af5cf 100644 --- a/Documentation/admin-guide/hw-vuln/spectre.rst +++ b/Documentation/admin-guide/hw-vuln/spectre.rst @@ -41,10 +41,11 @@ Related CVEs The following CVE entries describe Spectre variants: - ============= ======================= ================= + ============= ======================= ========================== CVE-2017-5753 Bounds check bypass Spectre variant 1 CVE-2017-5715 Branch target injection Spectre variant 2 - ============= ======================= ================= + CVE-2019-1125 Spectre v1 swapgs Spectre variant 1 (swapgs) + ============= ======================= ========================== Problem ------- @@ -78,6 +79,13 @@ There are some extensions of Spectre variant 1 attacks for reading data over the network, see :ref:`[12] <spec_ref12>`. However such attacks are difficult, low bandwidth, fragile, and are considered low risk. +Note that, despite "Bounds Check Bypass" name, Spectre variant 1 is not +only about user-controlled array bounds checks. It can affect any +conditional checks. The kernel entry code interrupt, exception, and NMI +handlers all have conditional swapgs checks. Those may be problematic +in the context of Spectre v1, as kernel code can speculatively run with +a user GS. + Spectre variant 2 (Branch Target Injection) ------------------------------------------- @@ -132,6 +140,9 @@ not cover all possible attack vectors. 1. A user process attacking the kernel ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ +Spectre variant 1 +~~~~~~~~~~~~~~~~~ + The attacker passes a parameter to the kernel via a register or via a known address in memory during a syscall. Such parameter may be used later by the kernel as an index to an array or to derive @@ -144,7 +155,40 @@ not cover all possible attack vectors. potentially be influenced for Spectre attacks, new "nospec" accessor macros are used to prevent speculative loading of data. - Spectre variant 2 attacker can :ref:`poison <poison_btb>` the branch +Spectre variant 1 (swapgs) +~~~~~~~~~~~~~~~~~~~~~~~~~~ + + An attacker can train the branch predictor to speculatively skip the + swapgs path for an interrupt or exception. If they initialize + the GS register to a user-space value, if the swapgs is speculatively + skipped, subsequent GS-related percpu accesses in the speculation + window will be done with the attacker-controlled GS value. This + could cause privileged memory to be accessed and leaked. + + For example: + + :: + + if (coming from user space) + swapgs + mov %gs:<percpu_offset>, %reg + mov (%reg), %reg1 + + When coming from user space, the CPU can speculatively skip the + swapgs, and then do a speculative percpu load using the user GS + value. So the user can speculatively force a read of any kernel + value. If a gadget exists which uses the percpu value as an address + in another load/store, then the contents of the kernel value may + become visible via an L1 side channel attack. + + A similar attack exists when coming from kernel space. The CPU can + speculatively do the swapgs, causing the user GS to get used for the + rest of the speculative window. + +Spectre variant 2 +~~~~~~~~~~~~~~~~~ + + A spectre variant 2 attacker can :ref:`poison <poison_btb>` the branch target buffer (BTB) before issuing syscall to launch an attack. After entering the kernel, the kernel could use the poisoned branch target buffer on indirect jump and jump to gadget code in speculative @@ -280,11 +324,18 @@ The sysfs file showing Spectre variant 1 mitigation status is: The possible values in this file are: - ======================================= ================================= - 'Mitigation: __user pointer sanitation' Protection in kernel on a case by - case base with explicit pointer - sanitation. - ======================================= ================================= + .. list-table:: + + * - 'Not affected' + - The processor is not vulnerable. + * - 'Vulnerable: __user pointer sanitization and usercopy barriers only; no swapgs barriers' + - The swapgs protections are disabled; otherwise it has + protection in the kernel on a case by case base with explicit + pointer sanitation and usercopy LFENCE barriers. + * - 'Mitigation: usercopy/swapgs barriers and __user pointer sanitization' + - Protection in the kernel on a case by case base with explicit + pointer sanitation, usercopy LFENCE barriers, and swapgs LFENCE + barriers. However, the protections are put in place on a case by case basis, and there is no guarantee that all possible attack vectors for Spectre @@ -366,12 +417,27 @@ Turning on mitigation for Spectre variant 1 and Spectre variant 2 1. Kernel mitigation ^^^^^^^^^^^^^^^^^^^^ +Spectre variant 1 +~~~~~~~~~~~~~~~~~ + For the Spectre variant 1, vulnerable kernel code (as determined by code audit or scanning tools) is annotated on a case by case basis to use nospec accessor macros for bounds clipping :ref:`[2] <spec_ref2>` to avoid any usable disclosure gadgets. However, it may not cover all attack vectors for Spectre variant 1. + Copy-from-user code has an LFENCE barrier to prevent the access_ok() + check from being mis-speculated. The barrier is done by the + barrier_nospec() macro. + + For the swapgs variant of Spectre variant 1, LFENCE barriers are + added to interrupt, exception and NMI entry where needed. These + barriers are done by the FENCE_SWAPGS_KERNEL_ENTRY and + FENCE_SWAPGS_USER_ENTRY macros. + +Spectre variant 2 +~~~~~~~~~~~~~~~~~ + For Spectre variant 2 mitigation, the compiler turns indirect calls or jumps in the kernel into equivalent return trampolines (retpolines) :ref:`[3] <spec_ref3>` :ref:`[9] <spec_ref9>` to go to the target @@ -473,6 +539,12 @@ Mitigation control on the kernel command line Spectre variant 2 mitigation can be disabled or force enabled at the kernel command line. + nospectre_v1 + + [X86,PPC] Disable mitigations for Spectre Variant 1 + (bounds check bypass). With this option data leaks are + possible in the system. + nospectre_v2 [X86] Disable all mitigations for the Spectre variant 2 diff --git a/Documentation/admin-guide/index.rst b/Documentation/admin-guide/index.rst index 33feab2f4084..34cc20ee7f3a 100644 --- a/Documentation/admin-guide/index.rst +++ b/Documentation/admin-guide/index.rst @@ -77,7 +77,10 @@ configure specific aspects of kernel behavior to your liking. blockdev/index ext4 binderfs + cifs/index xfs + jfs + ufs pm/index thunderbolt LSM/index @@ -98,6 +101,7 @@ configure specific aspects of kernel behavior to your liking. iostats kernel-per-CPU-kthreads laptops/index + auxdisplay/index lcd-panel-cgram ldm lockup-watchdogs @@ -105,6 +109,7 @@ configure specific aspects of kernel behavior to your liking. pnp rtc svga + wimax/index video-output .. only:: subproject and html diff --git a/Documentation/admin-guide/jfs.rst b/Documentation/admin-guide/jfs.rst new file mode 100644 index 000000000000..9e12d936bc90 --- /dev/null +++ b/Documentation/admin-guide/jfs.rst @@ -0,0 +1,66 @@ +=========================================== +IBM's Journaled File System (JFS) for Linux +=========================================== + +JFS Homepage: http://jfs.sourceforge.net/ + +The following mount options are supported: + +(*) == default + +iocharset=name + Character set to use for converting from Unicode to + ASCII. The default is to do no conversion. Use + iocharset=utf8 for UTF-8 translations. This requires + CONFIG_NLS_UTF8 to be set in the kernel .config file. + iocharset=none specifies the default behavior explicitly. + +resize=value + Resize the volume to <value> blocks. JFS only supports + growing a volume, not shrinking it. This option is only + valid during a remount, when the volume is mounted + read-write. The resize keyword with no value will grow + the volume to the full size of the partition. + +nointegrity + Do not write to the journal. The primary use of this option + is to allow for higher performance when restoring a volume + from backup media. The integrity of the volume is not + guaranteed if the system abnormally abends. + +integrity(*) + Commit metadata changes to the journal. Use this option to + remount a volume where the nointegrity option was + previously specified in order to restore normal behavior. + +errors=continue + Keep going on a filesystem error. +errors=remount-ro(*) + Remount the filesystem read-only on an error. +errors=panic + Panic and halt the machine if an error occurs. + +uid=value + Override on-disk uid with specified value +gid=value + Override on-disk gid with specified value +umask=value + Override on-disk umask with specified octal value. For + directories, the execute bit will be set if the corresponding + read bit is set. + +discard=minlen, discard/nodiscard(*) + This enables/disables the use of discard/TRIM commands. + The discard/TRIM commands are sent to the underlying + block device when blocks are freed. This is useful for SSD + devices and sparse/thinly-provisioned LUNs. The FITRIM ioctl + command is also available together with the nodiscard option. + The value of minlen specifies the minimum blockcount, when + a TRIM command to the block device is considered useful. + When no value is given to the discard option, it defaults to + 64 blocks, which means 256KiB in JFS. + The minlen value of discard overrides the minlen value given + on an FITRIM ioctl(). + +The JFS mailing list can be subscribed to by using the link labeled +"Mail list Subscribe" at our web page http://jfs.sourceforge.net/ diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index 7ccd158b3894..782e9072407b 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -1044,6 +1044,10 @@ specified address. The serial port must already be setup and configured. Options are not yet supported. + sbi + Use RISC-V SBI (Supervisor Binary Interface) for early + console. + smh Use ARM semihosting calls for early console. s3c2410,<addr> @@ -1090,6 +1094,12 @@ the framebuffer, pass the 'ram' option so that it is mapped with the correct attributes. + linflex,<addr> + Use early console provided by Freescale LinFlex UART + serial driver for NXP S32V234 SoCs. A valid base + address must be provided, and the serial port must + already be setup and configured. + earlyprintk= [X86,SH,ARM,M68k,S390] earlyprintk=vga earlyprintk=sclp @@ -1197,12 +1207,6 @@ See comment before function elanfreq_setup() in arch/x86/kernel/cpu/cpufreq/elanfreq.c. - elevator= [IOSCHED] - Format: { "mq-deadline" | "kyber" | "bfq" } - See Documentation/block/deadline-iosched.rst, - Documentation/block/kyber-iosched.rst and - Documentation/block/bfq-iosched.rst for details. - elfcorehdr=[size[KMG]@]offset[KMG] [IA64,PPC,SH,X86,S390] Specifies physical address of start of kernel core image elf header and optionally the size. Generally @@ -1732,6 +1736,11 @@ Note that using this option lowers the security provided by tboot because it makes the system vulnerable to DMA attacks. + nobounce [Default off] + Disable bounce buffer for unstrusted devices such as + the Thunderbolt devices. This will treat the untrusted + devices as the trusted ones, hence might expose security + risks of DMA attacks. intel_idle.max_cstate= [KNL,HW,ACPI,X86] 0 disables intel_idle and fall back on acpi_idle. @@ -1811,7 +1820,7 @@ synchronously. iommu.passthrough= - [ARM64] Configure DMA to bypass the IOMMU by default. + [ARM64, X86] Configure DMA to bypass the IOMMU by default. Format: { "0" | "1" } 0 - Use IOMMU translation for DMA. 1 - Bypass the IOMMU for DMA. @@ -2373,7 +2382,7 @@ machvec= [IA-64] Force the use of a particular machine-vector (machvec) in a generic kernel. - Example: machvec=hpzx1_swiotlb + Example: machvec=hpzx1 machtype= [Loongson] Share the same kernel image file between different yeeloong laptop. @@ -2604,7 +2613,7 @@ expose users to several CPU vulnerabilities. Equivalent to: nopti [X86,PPC] kpti=0 [ARM64] - nospectre_v1 [PPC] + nospectre_v1 [X86,PPC] nobp=0 [S390] nospectre_v2 [X86,PPC,S390,ARM64] spectre_v2_user=off [X86] @@ -2965,9 +2974,9 @@ nosmt=force: Force disable SMT, cannot be undone via the sysfs control file. - nospectre_v1 [PPC] Disable mitigations for Spectre Variant 1 (bounds - check bypass). With this option data leaks are possible - in the system. + nospectre_v1 [X86,PPC] Disable mitigations for Spectre Variant 1 + (bounds check bypass). With this option data leaks are + possible in the system. nospectre_v2 [X86,PPC_FSL_BOOK3E,ARM64] Disable all mitigations for the Spectre variant 2 (indirect branch prediction) @@ -3837,12 +3846,13 @@ RCU_BOOST is not set, valid values are 0-99 and the default is zero (non-realtime operation). - rcutree.rcu_nocb_leader_stride= [KNL] - Set the number of NOCB kthread groups, which - defaults to the square root of the number of - CPUs. Larger numbers reduces the wakeup overhead - on the per-CPU grace-period kthreads, but increases - that same overhead on each group's leader. + rcutree.rcu_nocb_gp_stride= [KNL] + Set the number of NOCB callback kthreads in + each group, which defaults to the square root + of the number of CPUs. Larger numbers reduce + the wakeup overhead on the global grace-period + kthread, but increases that same overhead on + each group's NOCB grace-period kthread. rcutree.qhimark= [KNL] Set threshold of queued RCU callbacks beyond which @@ -4047,6 +4057,10 @@ rcutorture.verbose= [KNL] Enable additional printk() statements. + rcupdate.rcu_cpu_stall_ftrace_dump= [KNL] + Dump ftrace buffer after reporting RCU CPU + stall warning. + rcupdate.rcu_cpu_stall_suppress= [KNL] Suppress RCU CPU stall warning messages. @@ -4090,6 +4104,13 @@ Run specified binary instead of /init from the ramdisk, used for early userspace startup. See initrd. + rdrand= [X86] + force - Override the decision by the kernel to hide the + advertisement of RDRAND support (this affects + certain AMD processors because of buggy BIOS + support, specifically around the suspend/resume + path). + rdt= [HW,X86,RDT] Turn on/off individual RDT features. List is: cmt, mbmtotal, mbmlocal, l3cat, l3cdp, l2cat, l2cdp, diff --git a/Documentation/admin-guide/kernel-per-CPU-kthreads.rst b/Documentation/admin-guide/kernel-per-CPU-kthreads.rst index 4f18456dd3b1..baeeba8762ae 100644 --- a/Documentation/admin-guide/kernel-per-CPU-kthreads.rst +++ b/Documentation/admin-guide/kernel-per-CPU-kthreads.rst @@ -274,9 +274,7 @@ To reduce its OS jitter, do any of the following: (based on an earlier one from Gilad Ben-Yossef) that reduces or even eliminates vmstat overhead for some workloads at https://lkml.org/lkml/2013/9/4/379. - e. Boot with "elevator=noop" to avoid workqueue use by - the block layer. - f. If running on high-end powerpc servers, build with + e. If running on high-end powerpc servers, build with CONFIG_PPC_RTAS_DAEMON=n. This prevents the RTAS daemon from running on each CPU every second or so. (This will require editing Kconfig files and will defeat @@ -284,12 +282,12 @@ To reduce its OS jitter, do any of the following: due to the rtas_event_scan() function. WARNING: Please check your CPU specifications to make sure that this is safe on your particular system. - g. If running on Cell Processor, build your kernel with + f. If running on Cell Processor, build your kernel with CBE_CPUFREQ_SPU_GOVERNOR=n to avoid OS jitter from spu_gov_work(). WARNING: Please check your CPU specifications to make sure that this is safe on your particular system. - h. If running on PowerMAC, build your kernel with + g. If running on PowerMAC, build your kernel with CONFIG_PMAC_RACKMETER=n to disable the CPU-meter, avoiding OS jitter from rackmeter_do_timer(). diff --git a/Documentation/admin-guide/laptops/thinkpad-acpi.rst b/Documentation/admin-guide/laptops/thinkpad-acpi.rst index adea0bf2acc5..822907dcc845 100644 --- a/Documentation/admin-guide/laptops/thinkpad-acpi.rst +++ b/Documentation/admin-guide/laptops/thinkpad-acpi.rst @@ -49,6 +49,7 @@ detailed description): - Fan control and monitoring: fan speed, fan enable/disable - WAN enable and disable - UWB enable and disable + - LCD Shadow (PrivacyGuard) enable and disable A compatibility table by model and feature is maintained on the web site, http://ibm-acpi.sf.net/. I appreciate any success or failure @@ -1409,6 +1410,28 @@ Sysfs notes Documentation/driver-api/rfkill.rst for details. +LCD Shadow control +------------------ + +procfs: /proc/acpi/ibm/lcdshadow + +Some newer T480s and T490s ThinkPads provide a feature called +PrivacyGuard. By turning this feature on, the usable vertical and +horizontal viewing angles of the LCD can be limited (as if some privacy +screen was applied manually in front of the display). + +procfs notes +^^^^^^^^^^^^ + +The available commands are:: + + echo '0' >/proc/acpi/ibm/lcdshadow + echo '1' >/proc/acpi/ibm/lcdshadow + +The first command ensures the best viewing angle and the latter one turns +on the feature, restricting the viewing angles. + + EXPERIMENTAL: UWB ----------------- diff --git a/Documentation/admin-guide/perf/imx-ddr.rst b/Documentation/admin-guide/perf/imx-ddr.rst new file mode 100644 index 000000000000..517a205abad6 --- /dev/null +++ b/Documentation/admin-guide/perf/imx-ddr.rst @@ -0,0 +1,52 @@ +===================================================== +Freescale i.MX8 DDR Performance Monitoring Unit (PMU) +===================================================== + +There are no performance counters inside the DRAM controller, so performance +signals are brought out to the edge of the controller where a set of 4 x 32 bit +counters is implemented. This is controlled by the CSV modes programed in counter +control register which causes a large number of PERF signals to be generated. + +Selection of the value for each counter is done via the config registers. There +is one register for each counter. Counter 0 is special in that it always counts +“time” and when expired causes a lock on itself and the other counters and an +interrupt is raised. If any other counter overflows, it continues counting, and +no interrupt is raised. + +The "format" directory describes format of the config (event ID) and config1 +(AXI filtering) fields of the perf_event_attr structure, see /sys/bus/event_source/ +devices/imx8_ddr0/format/. The "events" directory describes the events types +hardware supported that can be used with perf tool, see /sys/bus/event_source/ +devices/imx8_ddr0/events/. + e.g.:: + perf stat -a -e imx8_ddr0/cycles/ cmd + perf stat -a -e imx8_ddr0/read/,imx8_ddr0/write/ cmd + +AXI filtering is only used by CSV modes 0x41 (axid-read) and 0x42 (axid-write) +to count reading or writing matches filter setting. Filter setting is various +from different DRAM controller implementations, which is distinguished by quirks +in the driver. + +* With DDR_CAP_AXI_ID_FILTER quirk. + Filter is defined with two configuration parts: + --AXI_ID defines AxID matching value. + --AXI_MASKING defines which bits of AxID are meaningful for the matching. + 0：corresponding bit is masked. + 1: corresponding bit is not masked, i.e. used to do the matching. + + AXI_ID and AXI_MASKING are mapped on DPCR1 register in performance counter. + When non-masked bits are matching corresponding AXI_ID bits then counter is + incremented. Perf counter is incremented if + AxID && AXI_MASKING == AXI_ID && AXI_MASKING + + This filter doesn't support filter different AXI ID for axid-read and axid-write + event at the same time as this filter is shared between counters. + e.g.:: + perf stat -a -e imx8_ddr0/axid-read,axi_mask=0xMMMM,axi_id=0xDDDD/ cmd + perf stat -a -e imx8_ddr0/axid-write,axi_mask=0xMMMM,axi_id=0xDDDD/ cmd + + NOTE: axi_mask is inverted in userspace(i.e. set bits are bits to mask), and + it will be reverted in driver automatically. so that the user can just specify + axi_id to monitor a specific id, rather than having to specify axi_mask. + e.g.:: + perf stat -a -e imx8_ddr0/axid-read,axi_id=0x12/ cmd, which will monitor ARID=0x12 diff --git a/Documentation/admin-guide/sysctl/net.rst b/Documentation/admin-guide/sysctl/net.rst index a7d44e71019d..287b98708a40 100644 --- a/Documentation/admin-guide/sysctl/net.rst +++ b/Documentation/admin-guide/sysctl/net.rst @@ -39,7 +39,6 @@ Table : Subdirectories in /proc/sys/net 802 E802 protocol ax25 AX25 ethernet Ethernet protocol rose X.25 PLP layer ipv4 IP version 4 x25 X.25 protocol - ipx IPX token-ring IBM token ring bridge Bridging decnet DEC net ipv6 IP version 6 tipc TIPC ========= =================== = ========== ================== @@ -401,33 +400,7 @@ interface. (network) that the route leads to, the router (may be directly connected), the route flags, and the device the route is using. - -5. IPX ------- - -The IPX protocol has no tunable values in proc/sys/net. - -The IPX protocol does, however, provide proc/net/ipx. This lists each IPX -socket giving the local and remote addresses in Novell format (that is -network:node:port). In accordance with the strange Novell tradition, -everything but the port is in hex. Not_Connected is displayed for sockets that -are not tied to a specific remote address. The Tx and Rx queue sizes indicate -the number of bytes pending for transmission and reception. The state -indicates the state the socket is in and the uid is the owning uid of the -socket. - -The /proc/net/ipx_interface file lists all IPX interfaces. For each interface -it gives the network number, the node number, and indicates if the network is -the primary network. It also indicates which device it is bound to (or -Internal for internal networks) and the Frame Type if appropriate. Linux -supports 802.3, 802.2, 802.2 SNAP and DIX (Blue Book) ethernet framing for -IPX. - -The /proc/net/ipx_route table holds a list of IPX routes. For each route it -gives the destination network, the router node (or Directly) and the network -address of the router (or Connected) for internal networks. - -6. TIPC +5. TIPC ------- tipc_rmem diff --git a/Documentation/admin-guide/sysrq.rst b/Documentation/admin-guide/sysrq.rst index 7b9035c01a2e..72b2cfb066f4 100644 --- a/Documentation/admin-guide/sysrq.rst +++ b/Documentation/admin-guide/sysrq.rst @@ -171,22 +171,20 @@ It seems others find it useful as (System Attention Key) which is useful when you want to exit a program that will not let you switch consoles. (For example, X or a svgalib program.) -``reboot(b)`` is good when you're unable to shut down. But you should also -``sync(s)`` and ``umount(u)`` first. +``reboot(b)`` is good when you're unable to shut down, it is an equivalent +of pressing the "reset" button. ``crash(c)`` can be used to manually trigger a crashdump when the system is hung. Note that this just triggers a crash if there is no dump mechanism available. -``sync(s)`` is great when your system is locked up, it allows you to sync your -disks and will certainly lessen the chance of data loss and fscking. Note -that the sync hasn't taken place until you see the "OK" and "Done" appear -on the screen. (If the kernel is really in strife, you may not ever get the -OK or Done message...) +``sync(s)`` is handy before yanking removable medium or after using a rescue +shell that provides no graceful shutdown -- it will ensure your data is +safely written to the disk. Note that the sync hasn't taken place until you see +the "OK" and "Done" appear on the screen. -``umount(u)`` is basically useful in the same ways as ``sync(s)``. I generally -``sync(s)``, ``umount(u)``, then ``reboot(b)`` when my system locks. It's saved -me many a fsck. Again, the unmount (remount read-only) hasn't taken place until -you see the "OK" and "Done" message appear on the screen. +``umount(u)`` can be used to mark filesystems as properly unmounted. From the +running system's point of view, they will be remounted read-only. The remount +isn't complete until you see the "OK" and "Done" message appear on the screen. The loglevels ``0``-``9`` are useful when your console is being flooded with kernel messages you do not want to see. Selecting ``0`` will prevent all but diff --git a/Documentation/admin-guide/ufs.rst b/Documentation/admin-guide/ufs.rst new file mode 100644 index 000000000000..55d15297f8d7 --- /dev/null +++ b/Documentation/admin-guide/ufs.rst @@ -0,0 +1,68 @@ +========= +Using UFS +========= + +mount -t ufs -o ufstype=type_of_ufs device dir + + +UFS Options +=========== + +ufstype=type_of_ufs + UFS is a file system widely used in different operating systems. + The problem are differences among implementations. Features of + some implementations are undocumented, so its hard to recognize + type of ufs automatically. That's why user must specify type of + ufs manually by mount option ufstype. Possible values are: + + old + old format of ufs + default value, supported as read-only + + 44bsd + used in FreeBSD, NetBSD, OpenBSD + supported as read-write + + ufs2 + used in FreeBSD 5.x + supported as read-write + + 5xbsd + synonym for ufs2 + + sun + used in SunOS (Solaris) + supported as read-write + + sunx86 + used in SunOS for Intel (Solarisx86) + supported as read-write + + hp + used in HP-UX + supported as read-only + + nextstep + used in NextStep + supported as read-only + + nextstep-cd + used for NextStep CDROMs (block_size == 2048) + supported as read-only + + openstep + used in OpenStep + supported as read-only + + +Possible Problems +----------------- + +See next section, if you have any. + + +Bug Reports +----------- + +Any ufs bug report you can send to daniel.pirkl@email.cz or +to dushistov@mail.ru (do not send partition tables bug reports). diff --git a/Documentation/admin-guide/wimax/i2400m.rst b/Documentation/admin-guide/wimax/i2400m.rst new file mode 100644 index 000000000000..194388c0c351 --- /dev/null +++ b/Documentation/admin-guide/wimax/i2400m.rst @@ -0,0 +1,283 @@ +.. include:: <isonum.txt> + +==================================================== +Driver for the Intel Wireless Wimax Connection 2400m +==================================================== + +:Copyright: |copy| 2008 Intel Corporation < linux-wimax@intel.com > + + This provides a driver for the Intel Wireless WiMAX Connection 2400m + and a basic Linux kernel WiMAX stack. + +1. Requirements +=============== + + * Linux installation with Linux kernel 2.6.22 or newer (if building + from a separate tree) + * Intel i2400m Echo Peak or Baxter Peak; this includes the Intel + Wireless WiMAX/WiFi Link 5x50 series. + * build tools: + + + Linux kernel development package for the target kernel; to + build against your currently running kernel, you need to have + the kernel development package corresponding to the running + image installed (usually if your kernel is named + linux-VERSION, the development package is called + linux-dev-VERSION or linux-headers-VERSION). + + GNU C Compiler, make + +2. Compilation and installation +=============================== + +2.1. Compilation of the drivers included in the kernel +------------------------------------------------------ + + Configure the kernel; to enable the WiMAX drivers select Drivers > + Networking Drivers > WiMAX device support. Enable all of them as + modules (easier). + + If USB or SDIO are not enabled in the kernel configuration, the options + to build the i2400m USB or SDIO drivers will not show. Enable said + subsystems and go back to the WiMAX menu to enable the drivers. + + Compile and install your kernel as usual. + +2.2. Compilation of the drivers distributed as an standalone module +------------------------------------------------------------------- + + To compile:: + + $ cd source/directory + $ make + + Once built you can load and unload using the provided load.sh script; + load.sh will load the modules, load.sh u will unload them. + + To install in the default kernel directories (and enable auto loading + when the device is plugged):: + + $ make install + $ depmod -a + + If your kernel development files are located in a non standard + directory or if you want to build for a kernel that is not the + currently running one, set KDIR to the right location:: + + $ make KDIR=/path/to/kernel/dev/tree + + For more information, please contact linux-wimax@intel.com. + +3. Installing the firmware +-------------------------- + + The firmware can be obtained from http://linuxwimax.org or might have + been supplied with your hardware. + + It has to be installed in the target system:: + + $ cp FIRMWAREFILE.sbcf /lib/firmware/i2400m-fw-BUSTYPE-1.3.sbcf + + * NOTE: if your firmware came in an .rpm or .deb file, just install + it as normal, with the rpm (rpm -i FIRMWARE.rpm) or dpkg + (dpkg -i FIRMWARE.deb) commands. No further action is needed. + * BUSTYPE will be usb or sdio, depending on the hardware you have. + Each hardware type comes with its own firmware and will not work + with other types. + +4. Design +========= + + This package contains two major parts: a WiMAX kernel stack and a + driver for the Intel i2400m. + + The WiMAX stack is designed to provide for common WiMAX control + services to current and future WiMAX devices from any vendor; please + see README.wimax for details. + + The i2400m kernel driver is broken up in two main parts: the bus + generic driver and the bus-specific drivers. The bus generic driver + forms the drivercore and contain no knowledge of the actual method we + use to connect to the device. The bus specific drivers are just the + glue to connect the bus-generic driver and the device. Currently only + USB and SDIO are supported. See drivers/net/wimax/i2400m/i2400m.h for + more information. + + The bus generic driver is logically broken up in two parts: OS-glue and + hardware-glue. The OS-glue interfaces with Linux. The hardware-glue + interfaces with the device on using an interface provided by the + bus-specific driver. The reason for this breakup is to be able to + easily reuse the hardware-glue to write drivers for other OSes; note + the hardware glue part is written as a native Linux driver; no + abstraction layers are used, so to port to another OS, the Linux kernel + API calls should be replaced with the target OS's. + +5. Usage +======== + + To load the driver, follow the instructions in the install section; + once the driver is loaded, plug in the device (unless it is permanently + plugged in). The driver will enumerate the device, upload the firmware + and output messages in the kernel log (dmesg, /var/log/messages or + /var/log/kern.log) such as:: + + ... + i2400m_usb 5-4:1.0: firmware interface version 8.0.0 + i2400m_usb 5-4:1.0: WiMAX interface wmx0 (00:1d:e1:01:94:2c) ready + + At this point the device is ready to work. + + Current versions require the Intel WiMAX Network Service in userspace + to make things work. See the network service's README for instructions + on how to scan, connect and disconnect. + +5.1. Module parameters +---------------------- + + Module parameters can be set at kernel or module load time or by + echoing values:: + + $ echo VALUE > /sys/module/MODULENAME/parameters/PARAMETERNAME + + To make changes permanent, for example, for the i2400m module, you can + also create a file named /etc/modprobe.d/i2400m containing:: + + options i2400m idle_mode_disabled=1 + + To find which parameters are supported by a module, run:: + + $ modinfo path/to/module.ko + + During kernel bootup (if the driver is linked in the kernel), specify + the following to the kernel command line:: + + i2400m.PARAMETER=VALUE + +5.1.1. i2400m: idle_mode_disabled +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + + The i2400m module supports a parameter to disable idle mode. This + parameter, once set, will take effect only when the device is + reinitialized by the driver (eg: following a reset or a reconnect). + +5.2. Debug operations: debugfs entries +-------------------------------------- + + The driver will register debugfs entries that allow the user to tweak + debug settings. There are three main container directories where + entries are placed, which correspond to the three blocks a i2400m WiMAX + driver has: + + * /sys/kernel/debug/wimax:DEVNAME/ for the generic WiMAX stack + controls + * /sys/kernel/debug/wimax:DEVNAME/i2400m for the i2400m generic + driver controls + * /sys/kernel/debug/wimax:DEVNAME/i2400m-usb (or -sdio) for the + bus-specific i2400m-usb or i2400m-sdio controls). + + Of course, if debugfs is mounted in a directory other than + /sys/kernel/debug, those paths will change. + +5.2.1. Increasing debug output +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + + The files named *dl_* indicate knobs for controlling the debug output + of different submodules:: + + # find /sys/kernel/debug/wimax\:wmx0 -name \*dl_\* + /sys/kernel/debug/wimax:wmx0/i2400m-usb/dl_tx + /sys/kernel/debug/wimax:wmx0/i2400m-usb/dl_rx + /sys/kernel/debug/wimax:wmx0/i2400m-usb/dl_notif + /sys/kernel/debug/wimax:wmx0/i2400m-usb/dl_fw + /sys/kernel/debug/wimax:wmx0/i2400m-usb/dl_usb + /sys/kernel/debug/wimax:wmx0/i2400m/dl_tx + /sys/kernel/debug/wimax:wmx0/i2400m/dl_rx + /sys/kernel/debug/wimax:wmx0/i2400m/dl_rfkill + /sys/kernel/debug/wimax:wmx0/i2400m/dl_netdev + /sys/kernel/debug/wimax:wmx0/i2400m/dl_fw + /sys/kernel/debug/wimax:wmx0/i2400m/dl_debugfs + /sys/kernel/debug/wimax:wmx0/i2400m/dl_driver + /sys/kernel/debug/wimax:wmx0/i2400m/dl_control + /sys/kernel/debug/wimax:wmx0/wimax_dl_stack + /sys/kernel/debug/wimax:wmx0/wimax_dl_op_rfkill + /sys/kernel/debug/wimax:wmx0/wimax_dl_op_reset + /sys/kernel/debug/wimax:wmx0/wimax_dl_op_msg + /sys/kernel/debug/wimax:wmx0/wimax_dl_id_table + /sys/kernel/debug/wimax:wmx0/wimax_dl_debugfs + + By reading the file you can obtain the current value of said debug + level; by writing to it, you can set it. + + To increase the debug level of, for example, the i2400m's generic TX + engine, just write:: + + $ echo 3 > /sys/kernel/debug/wimax:wmx0/i2400m/dl_tx + + Increasing numbers yield increasing debug information; for details of + what is printed and the available levels, check the source. The code + uses 0 for disabled and increasing values until 8. + +5.2.2. RX and TX statistics +^^^^^^^^^^^^^^^^^^^^^^^^^^^ + + The i2400m/rx_stats and i2400m/tx_stats provide statistics about the + data reception/delivery from the device:: + + $ cat /sys/kernel/debug/wimax:wmx0/i2400m/rx_stats + 45 1 3 34 3104 48 480 + + The numbers reported are: + + * packets/RX-buffer: total, min, max + * RX-buffers: total RX buffers received, accumulated RX buffer size + in bytes, min size received, max size received + + Thus, to find the average buffer size received, divide accumulated + RX-buffer / total RX-buffers. + + To clear the statistics back to 0, write anything to the rx_stats file:: + + $ echo 1 > /sys/kernel/debug/wimax:wmx0/i2400m_rx_stats + + Likewise for TX. + + Note the packets this debug file refers to are not network packet, but + packets in the sense of the device-specific protocol for communication + to the host. See drivers/net/wimax/i2400m/tx.c. + +5.2.3. Tracing messages received from user space +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + + To echo messages received from user space into the trace pipe that the + i2400m driver creates, set the debug file i2400m/trace_msg_from_user to + 1:: + + $ echo 1 > /sys/kernel/debug/wimax:wmx0/i2400m/trace_msg_from_user + +5.2.4. Performing a device reset +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + + By writing a 0, a 1 or a 2 to the file + /sys/kernel/debug/wimax:wmx0/reset, the driver performs a warm (without + disconnecting from the bus), cold (disconnecting from the bus) or bus + (bus specific) reset on the device. + +5.2.5. Asking the device to enter power saving mode +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + + By writing any value to the /sys/kernel/debug/wimax:wmx0 file, the + device will attempt to enter power saving mode. + +6. Troubleshooting +================== + +6.1. Driver complains about ``i2400m-fw-usb-1.2.sbcf: request failed`` +---------------------------------------------------------------------- + + If upon connecting the device, the following is output in the kernel + log:: + + i2400m_usb 5-4:1.0: fw i2400m-fw-usb-1.3.sbcf: request failed: -2 + + This means that the driver cannot locate the firmware file named + /lib/firmware/i2400m-fw-usb-1.2.sbcf. Check that the file is present in + the right location. diff --git a/Documentation/admin-guide/wimax/index.rst b/Documentation/admin-guide/wimax/index.rst new file mode 100644 index 000000000000..fdf7c1f99ff5 --- /dev/null +++ b/Documentation/admin-guide/wimax/index.rst @@ -0,0 +1,19 @@ +.. SPDX-License-Identifier: GPL-2.0 + +=============== +WiMAX subsystem +=============== + +.. toctree:: + :maxdepth: 2 + + wimax + + i2400m + +.. only:: subproject and html + + Indices + ======= + + * :ref:`genindex` diff --git a/Documentation/admin-guide/wimax/wimax.rst b/Documentation/admin-guide/wimax/wimax.rst new file mode 100644 index 000000000000..817ee8ba2732 --- /dev/null +++ b/Documentation/admin-guide/wimax/wimax.rst @@ -0,0 +1,89 @@ +.. include:: <isonum.txt> + +======================== +Linux kernel WiMAX stack +======================== + +:Copyright: |copy| 2008 Intel Corporation < linux-wimax@intel.com > + + This provides a basic Linux kernel WiMAX stack to provide a common + control API for WiMAX devices, usable from kernel and user space. + +1. Design +========= + + The WiMAX stack is designed to provide for common WiMAX control + services to current and future WiMAX devices from any vendor. + + Because currently there is only one and we don't know what would be the + common services, the APIs it currently provides are very minimal. + However, it is done in such a way that it is easily extensible to + accommodate future requirements. + + The stack works by embedding a struct wimax_dev in your device's + control structures. This provides a set of callbacks that the WiMAX + stack will call in order to implement control operations requested by + the user. As well, the stack provides API functions that the driver + calls to notify about changes of state in the device. + + The stack exports the API calls needed to control the device to user + space using generic netlink as a marshalling mechanism. You can access + them using your own code or use the wrappers provided for your + convenience in libwimax (in the wimax-tools package). + + For detailed information on the stack, please see + include/linux/wimax.h. + +2. Usage +======== + + For usage in a driver (registration, API, etc) please refer to the + instructions in the header file include/linux/wimax.h. + + When a device is registered with the WiMAX stack, a set of debugfs + files will appear in /sys/kernel/debug/wimax:wmxX can tweak for + control. + +2.1. Obtaining debug information: debugfs entries +------------------------------------------------- + + The WiMAX stack is compiled, by default, with debug messages that can + be used to diagnose issues. By default, said messages are disabled. + + The drivers will register debugfs entries that allow the user to tweak + debug settings. + + Each driver, when registering with the stack, will cause a debugfs + directory named wimax:DEVICENAME to be created; optionally, it might + create more subentries below it. + +2.1.1. Increasing debug output +------------------------------ + + The files named *dl_* indicate knobs for controlling the debug output + of different submodules of the WiMAX stack:: + + # find /sys/kernel/debug/wimax\:wmx0 -name \*dl_\* + /sys/kernel/debug/wimax:wmx0/wimax_dl_stack + /sys/kernel/debug/wimax:wmx0/wimax_dl_op_rfkill + /sys/kernel/debug/wimax:wmx0/wimax_dl_op_reset + /sys/kernel/debug/wimax:wmx0/wimax_dl_op_msg + /sys/kernel/debug/wimax:wmx0/wimax_dl_id_table + /sys/kernel/debug/wimax:wmx0/wimax_dl_debugfs + /sys/kernel/debug/wimax:wmx0/.... # other driver specific files + + NOTE: + Of course, if debugfs is mounted in a directory other than + /sys/kernel/debug, those paths will change. + + By reading the file you can obtain the current value of said debug + level; by writing to it, you can set it. + + To increase the debug level of, for example, the id-table submodule, + just write: + + $ echo 3 > /sys/kernel/debug/wimax:wmx0/wimax_dl_id_table + + Increasing numbers yield increasing debug information; for details of + what is printed and the available levels, check the source. The code + uses 0 for disabled and increasing values until 8. diff --git a/Documentation/admin-guide/xfs.rst b/Documentation/admin-guide/xfs.rst index e76665a8f2f2..fb5b39f73059 100644 --- a/Documentation/admin-guide/xfs.rst +++ b/Documentation/admin-guide/xfs.rst @@ -337,11 +337,12 @@ None at present. Removed Sysctls =============== +============================= ======= Name Removed - ---- ------- +============================= ======= fs.xfs.xfsbufd_centisec v4.0 fs.xfs.age_buffer_centisecs v4.0 - +============================= ======= Error handling ============== |