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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-27 10:05:51 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-27 10:05:51 +0000
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+====
+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 https://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).