linux/fs/cifs/TODO
<<
>>
Prefs
   1Version 1.52 January 3, 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) ms-dfs and ms-dfs host name resolution cleanup
  24
  25f) fix NTLMv2 signing when two mounts with different users to same
  26server.
  27
  28g) Directory entry caching relies on a 1 second timer, rather than 
  29using FindNotify or equivalent.  - (started)
  30
  31h) quota support (needs minor kernel change since quota calls
  32to make it to network filesystems or deviceless filesystems)
  33
  34i) investigate sync behavior (including syncpage) and check  
  35for proper behavior of intr/nointr
  36
  37j) hook lower into the sockets api (as NFS/SunRPC does) to avoid the
  38extra copy in/out of the socket buffers in some cases.
  39
  40k) Better optimize open (and pathbased setfilesize) to reduce the
  41oplock breaks coming from windows srv.  Piggyback identical file
  42opens on top of each other by incrementing reference count rather
  43than resending (helps reduce server resource utilization and avoid
  44spurious oplock breaks).
  45
  46l) Improve performance of readpages by sending more than one read
  47at a time when 8 pages or more are requested. In conjuntion
  48add support for async_cifs_readpages.
  49
  50m) Add support for storing symlink info to Windows servers 
  51in the Extended Attribute format their SFU clients would recognize.
  52
  53n) Finish fcntl D_NOTIFY support so kde and gnome file list windows
  54will autorefresh (partially complete by Asser). Needs minor kernel
  55vfs change to support removing D_NOTIFY on a file.   
  56
  57o) Add GUI tool to configure /proc/fs/cifs settings and for display of
  58the CIFS statistics (started)
  59
  60p) implement support for security and trusted categories of xattrs
  61(requires minor protocol extension) to enable better support for SELINUX
  62
  63q) Implement O_DIRECT flag on open (already supported on mount)
  64
  65r) Create UID mapping facility so server UIDs can be mapped on a per
  66mount or a per server basis to client UIDs or nobody if no mapping
  67exists.  This is helpful when Unix extensions are negotiated to
  68allow better permission checking when UIDs differ on the server
  69and client.  Add new protocol request to the CIFS protocol 
  70standard for asking the server for the corresponding name of a
  71particular uid.
  72
  73s) Add support for CIFS Unix and also the newer POSIX extensions to the
  74server side for Samba 4.
  75
  76t) In support for OS/2 (LANMAN 1.2 and LANMAN2.1 based SMB servers) 
  77need to add ability to set time to server (utimes command)
  78
  79u) DOS attrs - returned as pseudo-xattr in Samba format (check VFAT and NTFS for this too)
  80
  81v) mount check for unmatched uids
  82
  83w) Add support for new vfs entry points for setlease and fallocate 
  84
  85x) Fix Samba 3 server to handle Linux kernel aio so dbench with lots of 
  86processes can proceed better in parallel (on the server)
  87
  88y) Fix Samba 3 to handle reads/writes over 127K (and remove the cifs mount
  89restriction of wsize max being 127K) 
  90
  91KNOWN BUGS (updated April 24, 2007)
  92====================================
  93See http://bugzilla.samba.org - search on product "CifsVFS" for
  94current bug list.
  95
  961) existing symbolic links (Windows reparse points) are recognized but
  97can not be created remotely. They are implemented for Samba and those that
  98support the CIFS Unix extensions, although earlier versions of Samba
  99overly restrict the pathnames.
 1002) follow_link and readdir code does not follow dfs junctions
 101but recognizes them
 1023) create of new files to FAT partitions on Windows servers can
 103succeed but still return access denied (appears to be Windows 
 104server not cifs client problem) and has not been reproduced recently.
 105NTFS partitions do not have this problem.
 1064) Unix/POSIX capabilities are reset after reconnection, and affect
 107a few fields in the tree connection but we do do not know which
 108superblocks to apply these changes to.  We should probably walk
 109the list of superblocks to set these.  Also need to check the
 110flags on the second mount to the same share, and see if we
 111can do the same trick that NFS does to remount duplicate shares.
 112
 113Misc testing to do
 114==================
 1151) check out max path names and max path name components against various server
 116types. Try nested symlinks (8 deep). Return max path name in stat -f information
 117
 1182) Modify file portion of ltp so it can run against a mounted network
 119share and run it against cifs vfs in automated fashion.
 120
 1213) Additional performance testing and optimization using iozone and similar - 
 122there are some easy changes that can be done to parallelize sequential writes,
 123and when signing is disabled to request larger read sizes (larger than 
 124negotiated size) and send larger write sizes to modern servers.
 125
 1264) More exhaustively test against less common servers.  More testing
 127against Windows 9x, Windows ME servers.
 128
 129
lxr.linux.no kindly hosted by Redpill Linpro AS, provider of Linux consulting and operations services since 1995.