[linux.git] / fs / cifs / TODO

version 1.34 April 29, 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 for chmod/chgrp/chown so
these can be supported for Windows servers

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

c) multi-user mounts - multiplexed sessionsetups over single vc
(ie tcp session) - more testing needed

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

h) quota support

j) finish writepages support (multi-page write behind for improved
performance) and syncpage

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 and fifo 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 (started)

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

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

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

s) Allow remapping of last remaining character (\) to +0xF000 which
(this character is valid for POSIX but not for Windows)

t) 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.

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.
Commit	Line	Data
9ea1f8f5	1	version 1.34 April 29, 2005
1da177e4 LT	2
	3	A Partial List of Missing Features
	4	==================================
	5
	6	Contributions are welcome. There are plenty of opportunities
	7	for visible, important contributions to this module. Here
	8	is a partial list of the known problems and missing features:
	9
	10	a) Support for SecurityDescriptors for chmod/chgrp/chown so
	11	these can be supported for Windows servers
	12
	13	b) Better pam/winbind integration (e.g. to handle uid mapping
	14	better)
	15
	16	c) multi-user mounts - multiplexed sessionsetups over single vc
6a0b4824	17	(ie tcp session) - more testing needed
1da177e4 LT	18
	19	d) Kerberos/SPNEGO session setup support - (started)
	20
	21	e) NTLMv2 authentication (mostly implemented)
	22
	23	f) MD5-HMAC signing SMB PDUs when SPNEGO style SessionSetup
	24	used (Kerberos or NTLMSSP). Signing alreadyimplemented for NTLM
	25	and raw NTLMSSP already. This is important when enabling
	26	extended security and mounting to Windows 2003 Servers
	27
	28	f) Directory entry caching relies on a 1 second timer, rather than
	29	using FindNotify or equivalent. - (started)
	30
	31	g) A few byte range testcases fail due to POSIX vs. Windows/CIFS
	32	style byte range lock differences
	33
	34	h) quota support
	35
	36	j) finish writepages support (multi-page write behind for improved
	37	performance) and syncpage
	38
	39	k) hook lower into the sockets api (as NFS/SunRPC does) to avoid the
	40	extra copy in/out of the socket buffers in some cases.
	41
	42	l) finish support for IPv6. This is mostly complete but
	43	needs a simple conversion of ipv6 to sin6_addr from the
	44	address in string representation.
	45
	46	m) Better optimize open (and pathbased setfilesize) to reduce the
	47	oplock breaks coming from windows srv. Piggyback identical file
	48	opens on top of each other by incrementing reference count rather
	49	than resending (helps reduce server resource utilization and avoid
	50	spurious oplock breaks).
	51
	52	o) Improve performance of readpages by sending more than one read
	53	at a time when 8 pages or more are requested. In conjuntion
	54	add support for async_cifs_readpages.
	55
	56	p) Add support for storing symlink and fifo info to Windows servers
	57	in the Extended Attribute format their SFU clients would recognize.
	58
	59	q) Finish fcntl D_NOTIFY support so kde and gnome file list windows
	60	will autorefresh (started)
	61
	62	r) Add GUI tool to configure /proc/fs/cifs settings and for display of
	63	the CIFS statistics (started)
	64
	65	q) implement support for security and trusted categories of xattrs
	66	(requires minor protocol extension) to enable better support for SELINUX
	67
	68	r) Implement O_DIRECT flag on open (already supported on mount)
	69
737b758c SF	70	s) Allow remapping of last remaining character (\) to +0xF000 which
	71	(this character is valid for POSIX but not for Windows)
	72
9ea1f8f5 SF	73	t) Create UID mapping facility so server UIDs can be mapped on a per
	74	mount or a per server basis to client UIDs or nobody if no mapping
	75	exists. This is helpful when Unix extensions are negotiated to
	76	allow better permission checking when UIDs differ on the server
	77	and client. Add new protocol request to the CIFS protocol
	78	standard for asking the server for the corresponding name of a
	79	particular uid.
	80
	81	KNOWN BUGS (updated April 29, 2005)
1da177e4	82	====================================
6a0b4824 SF	83	See http://bugzilla.samba.org - search on product "CifsVFS" for
	84	current bug list.
	85
1da177e4 LT	86	1) existing symbolic links (Windows reparse points) are recognized but
1da177e4 LT	87	can not be created remotely. They are implemented for Samba and those that
6a0b4824 SF	88	support the CIFS Unix extensions, although earlier versions of Samba
6a0b4824 SF	89	overly restrict the pathnames.
1da177e4 LT	90	2) follow_link and readdir code does not follow dfs junctions
	91	but recognizes them
	92	3) create of new files to FAT partitions on Windows servers can
	93	succeed but still return access denied (appears to be Windows
	94	server not cifs client problem) and has not been reproduced recently.
	95	NTFS partitions do not have this problem.
	96	4) debug connectathon lock test case 10 which fails against
	97	Samba (may be unmappable due to POSIX to Windows lock model
	98	differences but worth investigating). Also debug Samba to
	99	see why lock test case 7 takes longer to complete to Samba
	100	than to Windows.
	101
	102	Misc testing to do
	103	==================
	104	1) check out max path names and max path name components against various server
	105	types. Try nested symlinks (8 deep). Return max path name in stat -f information
	106
	107	2) Modify file portion of ltp so it can run against a mounted network
	108	share and run it against cifs vfs.
	109
	110	3) Additional performance testing and optimization using iozone and similar -
	111	there are some easy changes that can be done to parallelize sequential writes,
	112	and when signing is disabled to request larger read sizes (larger than
	113	negotiated size) and send larger write sizes to modern servers.
	114
6a0b4824 SF	115	4) More exhaustively test against less common servers. More testing
6a0b4824 SF	116	against Windows 9x, Windows ME servers.