|Version 1.53 May 20, 2008
|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) Support for SecurityDescriptors(Windows/CIFS ACLs) for chmod/chgrp/chown
|so that these operations can be supported to Windows servers
|b) Mapping POSIX ACLs (and eventually NFSv4 ACLs) to CIFS
|c) Better pam/winbind integration (e.g. to handle uid mapping
|d) Cleanup now unneeded SessSetup code in
|fs/cifs/connect.c and add back in NTLMSSP code if any servers
|e) fix NTLMv2 signing when two mounts with different users to same
|f) Directory entry caching relies on a 1 second timer, rather than
|using FindNotify or equivalent. - (started)
|g) quota support (needs minor kernel change since quota calls
|to make it to network filesystems or deviceless filesystems)
|h) investigate sync behavior (including syncpage) and check
|for proper behavior of intr/nointr
|i) improve support for very old servers (OS/2 and Win9x for example)
|Including support for changing the time remotely (utimes command).
|j) hook lower into the sockets api (as NFS/SunRPC does) to avoid the
|extra copy in/out of the socket buffers in some cases.
|k) Better optimize open (and pathbased setfilesize) to reduce the
|oplock breaks coming from windows srv. Piggyback identical file
|opens on top of each other by incrementing reference count rather
|than resending (helps reduce server resource utilization and avoid
|spurious oplock breaks).
|l) Improve performance of readpages by sending more than one read
|at a time when 8 pages or more are requested. In conjuntion
|add support for async_cifs_readpages.
|m) Add support for storing symlink info to Windows servers
|in the Extended Attribute format their SFU clients would recognize.
|n) Finish fcntl D_NOTIFY 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.
|o) Add GUI tool to configure /proc/fs/cifs settings and for display of
|the CIFS statistics (started)
|p) implement support for security and trusted categories of xattrs
|(requires minor protocol extension) to enable better support for SELINUX
|q) Implement O_DIRECT flag on open (already supported on mount)
|r) 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. This is helpful when Unix extensions are negotiated to
|allow better permission checking when UIDs differ on the server
|and client. Add new protocol request to the CIFS protocol
|standard for asking the server for the corresponding name of a
|s) Add support for CIFS Unix and also the newer POSIX extensions to the
|server side for Samba 4.
|t) In support for OS/2 (LANMAN 1.2 and LANMAN2.1 based SMB servers)
|need to add ability to set time to server (utimes command)
|u) DOS attrs - returned as pseudo-xattr in Samba format (check VFAT and NTFS for this too)
|v) mount check for unmatched uids
|w) Add support for new vfs entry points for setlease and fallocate
|x) Fix Samba 3 server to handle Linux kernel aio so dbench with lots of
|processes can proceed better in parallel (on the server)
|y) Fix Samba 3 to handle reads/writes over 127K (and remove the cifs mount
|restriction of wsize max being 127K)
|KNOWN BUGS (updated April 24, 2007)
|See http://bugzilla.samba.org - search on product "CifsVFS" for
|current bug list.
|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
|3) create of new files to FAT partitions on Windows servers can
|succeed but still return access denied (appears to be Windows
|server not cifs client problem) and has not been reproduced recently.
|NTFS partitions do not have this problem.
|4) Unix/POSIX capabilities are reset after reconnection, and affect
|a few fields in the tree connection but we do do not know which
|superblocks to apply these changes to. We should probably walk
|the list of superblocks to set these. Also need to check the
|flags on the second mount to the same share, and see if we
|can do the same trick that NFS does to remount duplicate shares.
|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) Modify file portion of ltp so it can run against a mounted network
|share and run it against cifs vfs in automated fashion.
|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. More testing
|against Windows 9x, Windows ME servers.