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Diffstat (limited to 'Documentation/filesystems/cifs')
| -rw-r--r-- | Documentation/filesystems/cifs/AUTHORS | 63 | ||||
| -rw-r--r-- | Documentation/filesystems/cifs/CHANGES | 4 | ||||
| -rw-r--r-- | Documentation/filesystems/cifs/README | 743 | ||||
| -rw-r--r-- | Documentation/filesystems/cifs/TODO | 104 | ||||
| -rw-r--r-- | Documentation/filesystems/cifs/cifs.txt | 35 | ||||
| -rwxr-xr-x | Documentation/filesystems/cifs/winucase_convert.pl | 62 |
6 files changed, 1011 insertions, 0 deletions
diff --git a/Documentation/filesystems/cifs/AUTHORS b/Documentation/filesystems/cifs/AUTHORS new file mode 100644 index 000000000..75865da2c --- /dev/null +++ b/Documentation/filesystems/cifs/AUTHORS @@ -0,0 +1,63 @@ +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/filesystems/cifs/CHANGES b/Documentation/filesystems/cifs/CHANGES new file mode 100644 index 000000000..1df7f4910 --- /dev/null +++ b/Documentation/filesystems/cifs/CHANGES @@ -0,0 +1,4 @@ +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/filesystems/cifs/README b/Documentation/filesystems/cifs/README new file mode 100644 index 000000000..4a804619c --- /dev/null +++ b/Documentation/filesystems/cifs/README @@ -0,0 +1,743 @@ +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 (ie which take longer than 1 second) + CONFIG_CIFS_STATS2 must be enabled in .config 0x04 + + +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/filesystems/cifs/TODO b/Documentation/filesystems/cifs/TODO new file mode 100644 index 000000000..852499aed --- /dev/null +++ b/Documentation/filesystems/cifs/TODO @@ -0,0 +1,104 @@ +Version 2.11 September 13, 2017 + +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 SMB3.02) 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 + +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) Compounding (in progress) to reduce number of roundtrips, and also +better optimize open to reduce redundant opens (using reference counts more). + +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 for sending various SMB3 fsctls to the server +is in progress) + +l) encrypted file support + +m) improved stats gathering, tools (perhaps integration with nfsometer?) + +n) allow setting more NTFS/SMB3 file attributes remotely (currently limited to compressed +file attribute via chflags) and improve user space tools for managing and +viewing them. + +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). + +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 diff --git a/Documentation/filesystems/cifs/cifs.txt b/Documentation/filesystems/cifs/cifs.txt new file mode 100644 index 000000000..677566072 --- /dev/null +++ b/Documentation/filesystems/cifs/cifs.txt @@ -0,0 +1,35 @@ + This is the client VFS module for the SMB3 NAS protocol as well + 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. These dialects are also supported by the + CIFS VFS module. CIFS is fully supported by network + file servers such as Windows 2000, 2003, 2008, 2012 and 2016 + as well by Samba (which provides excellent CIFS + server support for Linux and many other operating systems), Apple + systems, as well as most Network Attached Storage vendors, so + this network filesystem client can mount to a wide variety of + servers. + + 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 an mount utility (mount.cifs) that can be obtained from + + https://ftp.samba.org/pub/linux-cifs/cifs-utils/ + + It must 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_utils diff --git a/Documentation/filesystems/cifs/winucase_convert.pl b/Documentation/filesystems/cifs/winucase_convert.pl new file mode 100755 index 000000000..322a9c833 --- /dev/null +++ b/Documentation/filesystems/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"; |