fs/cifs/TODO - kernel/msm - Gitiles

 Version 1.39 November 30, 2005

 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
 SecurityDescriptors

 c) Better pam/winbind integration (e.g. to handle uid mapping
 better)

 d) Kerberos/SPNEGO session setup support - (started)

 e) NTLMv2 authentication (mostly implemented)

 f) MD5-HMAC signing SMB PDUs when SPNEGO style SessionSetup
 used (Kerberos or NTLMSSP). Signing alreadyimplemented for NTLM
 and raw NTLMSSP already. This is important when enabling
 extended security and mounting to Windows 2003 Servers

 f) Directory entry caching relies on a 1 second timer, rather than
 using FindNotify or equivalent.  - (started)

 g) A few byte range testcases fail due to POSIX vs. Windows/CIFS
 style byte range lock differences.  Save byte range locks so
 reconnect can replay them.

 h) Support unlock all (unlock 0,MAX_OFFSET)
 by unlocking all known byte range locks that we locked on the file.

 i) quota support (needs minor kernel change since quota calls
 to make it to network filesystems or deviceless filesystems)

 j) investigate sync behavior (including syncpage) and check
 for proper behavior of intr/nointr

 k) hook lower into the sockets api (as NFS/SunRPC does) to avoid the
 extra copy in/out of the socket buffers in some cases.

 l) finish support for IPv6.  This is mostly complete but
 needs a simple conversion of ipv6 to sin6_addr from the
 address in string representation.

 m) 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).

 o) 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.

 p) Add support for storing symlink info to Windows servers
 in the Extended Attribute format their SFU clients would recognize.

 q) 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.

 r) Add GUI tool to configure /proc/fs/cifs settings and for display of
 the CIFS statistics (started)

 s) implement support for security and trusted categories of xattrs
 (requires minor protocol extension) to enable better support for SELINUX

 t) Implement O_DIRECT flag on open (already supported on mount)

 u) 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
 particular uid.

 v) Add support for CIFS Unix and also the newer POSIX extensions to the
 server side for Samba 4.

 w) Finish up the dos time conversion routines needed to return old server
 time to the client (default time, of now or time 0 is used now for these
 very old servers)

 x) Add support for OS/2 (LANMAN 1.2 and LANMAN2.1 based SMB servers)

 y) Finish testing of Windows 9x/Windows ME server support (started).

 KNOWN BUGS (updated April 29, 2005)
 ====================================
 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) debug connectathon lock test case 10 which fails against
 Samba (may be unmappable due to POSIX to Windows lock model
 differences but worth investigating).  Also debug Samba to
 see why lock test case 7 takes longer to complete to Samba
 than to Windows.

 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.

 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.

 DOS attrs - returned as pseudo-xattr in Samba format (check VFAT and NTFS for this too)

 mount check for unmatched uids - and uid override

 Add mount option for Linux extension disable per mount, and partial disable per mount (uid off, symlink/fifo/mknod on but what about posix acls?)

 Free threads at umount --force that are stuck on the sesSem
	Version 1.39 November 30, 2005

	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
	SecurityDescriptors

	c) Better pam/winbind integration (e.g. to handle uid mapping
	better)

	d) Kerberos/SPNEGO session setup support - (started)

	e) NTLMv2 authentication (mostly implemented)

	f) MD5-HMAC signing SMB PDUs when SPNEGO style SessionSetup
	used (Kerberos or NTLMSSP). Signing alreadyimplemented for NTLM
	and raw NTLMSSP already. This is important when enabling
	extended security and mounting to Windows 2003 Servers

	f) Directory entry caching relies on a 1 second timer, rather than
	using FindNotify or equivalent. - (started)

	g) A few byte range testcases fail due to POSIX vs. Windows/CIFS
	style byte range lock differences. Save byte range locks so
	reconnect can replay them.

	h) Support unlock all (unlock 0,MAX_OFFSET)
	by unlocking all known byte range locks that we locked on the file.

	i) quota support (needs minor kernel change since quota calls
	to make it to network filesystems or deviceless filesystems)

	j) investigate sync behavior (including syncpage) and check
	for proper behavior of intr/nointr

	k) hook lower into the sockets api (as NFS/SunRPC does) to avoid the
	extra copy in/out of the socket buffers in some cases.

	l) finish support for IPv6. This is mostly complete but
	needs a simple conversion of ipv6 to sin6_addr from the
	address in string representation.

	m) 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).

	o) 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.

	p) Add support for storing symlink info to Windows servers
	in the Extended Attribute format their SFU clients would recognize.

	q) 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.

	r) Add GUI tool to configure /proc/fs/cifs settings and for display of
	the CIFS statistics (started)

	s) implement support for security and trusted categories of xattrs
	(requires minor protocol extension) to enable better support for SELINUX

	t) Implement O_DIRECT flag on open (already supported on mount)

	u) 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
	particular uid.

	v) Add support for CIFS Unix and also the newer POSIX extensions to the
	server side for Samba 4.

	w) Finish up the dos time conversion routines needed to return old server
	time to the client (default time, of now or time 0 is used now for these
	very old servers)

	x) Add support for OS/2 (LANMAN 1.2 and LANMAN2.1 based SMB servers)

	y) Finish testing of Windows 9x/Windows ME server support (started).

	KNOWN BUGS (updated April 29, 2005)
	====================================
	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) debug connectathon lock test case 10 which fails against
	Samba (may be unmappable due to POSIX to Windows lock model
	differences but worth investigating). Also debug Samba to
	see why lock test case 7 takes longer to complete to Samba
	than to Windows.

	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.

	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.

	DOS attrs - returned as pseudo-xattr in Samba format (check VFAT and NTFS for this too)

	mount check for unmatched uids - and uid override

	Add mount option for Linux extension disable per mount, and partial disable per mount (uid off, symlink/fifo/mknod on but what about posix acls?)

	Free threads at umount --force that are stuck on the sesSem