1Version 2.11 September 13, 2017
  2
  3A Partial List of Missing Features
  4==================================
  5
  6Contributions are welcome.  There are plenty of opportunities
  7for visible, important contributions to this module.  Here
  8is a partial list of the known problems and missing features:
  9
 10a) SMB3 (and SMB3.02) missing optional features:
 11   - multichannel (started), integration with RDMA
 12   - directory leases (improved metadata caching)
 13   - T10 copy offload (copy chunk, and "Duplicate Extents" ioctl
 14     currently the only two server side copy mechanisms supported)
 15
 16b) improved sparse file support
 
 17
 18c) Directory entry caching relies on a 1 second timer, rather than
 19using Directory Leases
 20
 21d) quota support (needs minor kernel change since quota calls
 
 
 
 
 
 
 
 
 
 
 22to make it to network filesystems or deviceless filesystems)
 23
 24e) Compounding (in progress) to reduce number of roundtrips, and also
 25better optimize open to reduce redundant opens (using reference counts more).
 26
 27f) Finish inotify support so kde and gnome file list windows
 28will autorefresh (partially complete by Asser). Needs minor kernel
 29vfs change to support removing D_NOTIFY on a file.   
 30
 31g) Add GUI tool to configure /proc/fs/cifs settings and for display of
 32the CIFS statistics (started)
 33
 34h) implement support for security and trusted categories of xattrs
 35(requires minor protocol extension) to enable better support for SELINUX
 
 
 
 36
 37i) Add support for tree connect contexts (see MS-SMB2) a new SMB3.1.1 protocol
 38   feature (may be especially useful for virtualization).
 
 39
 40j) Create UID mapping facility so server UIDs can be mapped on a per
 41mount or a per server basis to client UIDs or nobody if no mapping
 42exists. Also better integration with winbind for resolving SID owners
 43
 44k) Add tools to take advantage of more smb3 specific ioctls and features
 
 
 45
 46l) encrypted file support
 
 47
 48m) improved stats gathering, tools (perhaps integration with nfsometer?)
 
 49
 50n) allow setting more NTFS/SMB3 file attributes remotely (currently limited to compressed
 51file attribute via chflags) and improve user space tools for managing and
 52viewing them.
 53
 54o) mount helper GUI (to simplify the various configuration options on mount)
 
 
 
 
 
 
 55
 56p) Add support for witness protocol (perhaps ioctl to cifs.ko from user space
 57   tool listening on witness protocol RPC) to allow for notification of share
 58   move, server failover, and server adapter changes.  And also improve other
 59   failover scenarios, e.g. when client knows multiple DFS entries point to
 60   different servers, and the server we are connected to has gone down.
 61
 62q) Allow mount.cifs to be more verbose in reporting errors with dialect
 63or unsupported feature errors.
 64
 65r) updating cifs documentation, and user guide.
 66
 67s) Addressing bugs found by running a broader set of xfstests in standard
 68file system xfstest suite.
 69
 70t) split cifs and smb3 support into separate modules so legacy (and less
 71secure) CIFS dialect can be disabled in environments that don't need it
 72and simplify the code.
 73
 74u) Finish up SMB3.1.1 dialect support
 
 75
 76v) POSIX Extensions for SMB3.1.1
 
 77
 78KNOWN BUGS
 79====================================
 80See http://bugzilla.samba.org - search on product "CifsVFS" for
 81current bug list.  Also check http://bugzilla.kernel.org (Product = File System, Component = CIFS)
 82
 831) existing symbolic links (Windows reparse points) are recognized but
 84can not be created remotely. They are implemented for Samba and those that
 85support the CIFS Unix extensions, although earlier versions of Samba
 86overly restrict the pathnames.
 872) follow_link and readdir code does not follow dfs junctions
 88but recognizes them
 
 
 
 
 
 
 
 
 
 
 89
 90Misc testing to do
 91==================
 921) check out max path names and max path name components against various server
 93types. Try nested symlinks (8 deep). Return max path name in stat -f information
 94
 952) Improve xfstest's cifs enablement and adapt xfstests where needed to test
 96cifs better
 97
 983) Additional performance testing and optimization using iozone and similar - 
 99there are some easy changes that can be done to parallelize sequential writes,
100and when signing is disabled to request larger read sizes (larger than 
101negotiated size) and send larger write sizes to modern servers.
102
1034) More exhaustively test against less common servers
 
 

  1Version 1.53 May 20, 2008
  2
  3A Partial List of Missing Features
  4==================================
  5
  6Contributions are welcome.  There are plenty of opportunities
  7for visible, important contributions to this module.  Here
  8is a partial list of the known problems and missing features:
  9
 10a) Support for SecurityDescriptors(Windows/CIFS ACLs) for chmod/chgrp/chown
 11so that these operations can be supported to Windows servers
 
 
 
 12
 13b) Mapping POSIX ACLs (and eventually NFSv4 ACLs) to CIFS
 14SecurityDescriptors
 15
 16c) Better pam/winbind integration (e.g. to handle uid mapping
 17better)
 18
 19d) Cleanup now unneeded SessSetup code in
 20fs/cifs/connect.c and add back in NTLMSSP code if any servers
 21need it
 22
 23e) fix NTLMv2 signing when two mounts with different users to same
 24server.
 25
 26f) Directory entry caching relies on a 1 second timer, rather than 
 27using FindNotify or equivalent.  - (started)
 28
 29g) quota support (needs minor kernel change since quota calls
 30to make it to network filesystems or deviceless filesystems)
 31
 32h) investigate sync behavior (including syncpage) and check  
 33for proper behavior of intr/nointr
 34
 35i) improve support for very old servers (OS/2 and Win9x for example)
 36Including support for changing the time remotely (utimes command).
 
 37
 38j) hook lower into the sockets api (as NFS/SunRPC does) to avoid the
 39extra copy in/out of the socket buffers in some cases.
 40
 41k) Better optimize open (and pathbased setfilesize) to reduce the
 42oplock breaks coming from windows srv.  Piggyback identical file
 43opens on top of each other by incrementing reference count rather
 44than resending (helps reduce server resource utilization and avoid
 45spurious oplock breaks).
 46
 47l) Improve performance of readpages by sending more than one read
 48at a time when 8 pages or more are requested. In conjuntion
 49add support for async_cifs_readpages.
 50
 51m) Add support for storing symlink info to Windows servers 
 52in the Extended Attribute format their SFU clients would recognize.
 
 53
 54n) Finish fcntl D_NOTIFY support so kde and gnome file list windows
 55will autorefresh (partially complete by Asser). Needs minor kernel
 56vfs change to support removing D_NOTIFY on a file.   
 57
 58o) Add GUI tool to configure /proc/fs/cifs settings and for display of
 59the CIFS statistics (started)
 60
 61p) implement support for security and trusted categories of xattrs
 62(requires minor protocol extension) to enable better support for SELINUX
 63
 64q) Implement O_DIRECT flag on open (already supported on mount)
 
 
 65
 66r) Create UID mapping facility so server UIDs can be mapped on a per
 67mount or a per server basis to client UIDs or nobody if no mapping
 68exists.  This is helpful when Unix extensions are negotiated to
 69allow better permission checking when UIDs differ on the server
 70and client.  Add new protocol request to the CIFS protocol 
 71standard for asking the server for the corresponding name of a
 72particular uid.
 73
 74s) Add support for CIFS Unix and also the newer POSIX extensions to the
 75server side for Samba 4.
 
 
 
 76
 77t) In support for OS/2 (LANMAN 1.2 and LANMAN2.1 based SMB servers) 
 78need to add ability to set time to server (utimes command)
 79
 80u) DOS attrs - returned as pseudo-xattr in Samba format (check VFAT and NTFS for this too)
 81
 82v) mount check for unmatched uids
 
 83
 84w) Add support for new vfs entry point for fallocate
 
 
 85
 86x) Fix Samba 3 server to handle Linux kernel aio so dbench with lots of 
 87processes can proceed better in parallel (on the server)
 88
 89y) Fix Samba 3 to handle reads/writes over 127K (and remove the cifs mount
 90restriction of wsize max being 127K) 
 91
 92KNOWN BUGS (updated April 24, 2007)
 93====================================
 94See http://bugzilla.samba.org - search on product "CifsVFS" for
 95current bug list.
 96
 971) existing symbolic links (Windows reparse points) are recognized but
 98can not be created remotely. They are implemented for Samba and those that
 99support the CIFS Unix extensions, although earlier versions of Samba
100overly restrict the pathnames.
1012) follow_link and readdir code does not follow dfs junctions
102but recognizes them
1033) create of new files to FAT partitions on Windows servers can
104succeed but still return access denied (appears to be Windows 
105server not cifs client problem) and has not been reproduced recently.
106NTFS partitions do not have this problem.
1074) Unix/POSIX capabilities are reset after reconnection, and affect
108a few fields in the tree connection but we do do not know which
109superblocks to apply these changes to.  We should probably walk
110the list of superblocks to set these.  Also need to check the
111flags on the second mount to the same share, and see if we
112can do the same trick that NFS does to remount duplicate shares.
113
114Misc testing to do
115==================
1161) check out max path names and max path name components against various server
117types. Try nested symlinks (8 deep). Return max path name in stat -f information
118
1192) Modify file portion of ltp so it can run against a mounted network
120share and run it against cifs vfs in automated fashion.
121
1223) Additional performance testing and optimization using iozone and similar - 
123there are some easy changes that can be done to parallelize sequential writes,
124and when signing is disabled to request larger read sizes (larger than 
125negotiated size) and send larger write sizes to modern servers.
126
1274) More exhaustively test against less common servers.  More testing
128against Windows 9x, Windows ME servers.
129