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![Steve French](/assets/img/avatar_default.png)
Caused by unneeded reopen during reconnect while spinlock held. Fixes kernel bugzilla bug #7903 Thanks to Lin Feng Shen for testing this, and Amit Arora for some nice problem determination to narrow this down. Acked-by: Dave Kleikamp <shaggy@us.ibm.com> Signed-off-by: Steve French <sfrench@us.ibm.com>
130 lines
5.3 KiB
Text
130 lines
5.3 KiB
Text
Version 1.49 April 26, 2007
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A Partial List of Missing Features
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==================================
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Contributions are welcome. There are plenty of opportunities
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for visible, important contributions to this module. Here
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is a partial list of the known problems and missing features:
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a) Support for SecurityDescriptors(Windows/CIFS ACLs) for chmod/chgrp/chown
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so that these operations can be supported to Windows servers
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b) Mapping POSIX ACLs (and eventually NFSv4 ACLs) to CIFS
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SecurityDescriptors
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c) Better pam/winbind integration (e.g. to handle uid mapping
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better)
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d) Kerberos/SPNEGO session setup support - (started)
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e) Cleanup now unneeded SessSetup code in
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fs/cifs/connect.c and add back in NTLMSSP code if any servers
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need it
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f) MD5-HMAC signing SMB PDUs when SPNEGO style SessionSetup
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used (Kerberos or NTLMSSP). Signing alreadyimplemented for NTLM
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and raw NTLMSSP already. This is important when enabling
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extended security and mounting to Windows 2003 Servers
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g) Directory entry caching relies on a 1 second timer, rather than
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using FindNotify or equivalent. - (started)
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h) quota support (needs minor kernel change since quota calls
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to make it to network filesystems or deviceless filesystems)
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i) investigate sync behavior (including syncpage) and check
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for proper behavior of intr/nointr
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j) hook lower into the sockets api (as NFS/SunRPC does) to avoid the
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extra copy in/out of the socket buffers in some cases.
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k) Better optimize open (and pathbased setfilesize) to reduce the
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oplock breaks coming from windows srv. Piggyback identical file
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opens on top of each other by incrementing reference count rather
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than resending (helps reduce server resource utilization and avoid
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spurious oplock breaks).
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l) Improve performance of readpages by sending more than one read
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at a time when 8 pages or more are requested. In conjuntion
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add support for async_cifs_readpages.
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m) Add support for storing symlink info to Windows servers
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in the Extended Attribute format their SFU clients would recognize.
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n) Finish fcntl D_NOTIFY support so kde and gnome file list windows
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will autorefresh (partially complete by Asser). Needs minor kernel
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vfs change to support removing D_NOTIFY on a file.
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o) Add GUI tool to configure /proc/fs/cifs settings and for display of
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the CIFS statistics (started)
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p) implement support for security and trusted categories of xattrs
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(requires minor protocol extension) to enable better support for SELINUX
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q) Implement O_DIRECT flag on open (already supported on mount)
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r) Create UID mapping facility so server UIDs can be mapped on a per
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mount or a per server basis to client UIDs or nobody if no mapping
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exists. This is helpful when Unix extensions are negotiated to
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allow better permission checking when UIDs differ on the server
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and client. Add new protocol request to the CIFS protocol
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standard for asking the server for the corresponding name of a
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particular uid.
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s) Add support for CIFS Unix and also the newer POSIX extensions to the
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server side for Samba 4.
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t) In support for OS/2 (LANMAN 1.2 and LANMAN2.1 based SMB servers)
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need to add ability to set time to server (utimes command)
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u) DOS attrs - returned as pseudo-xattr in Samba format (check VFAT and NTFS for this too)
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v) mount check for unmatched uids
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w) Add support for new vfs entry points for setlease and fallocate
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x) Fix Samba 3 server to handle Linux kernel aio so dbench with lots of
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processes can proceed better in parallel (on the server)
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y) Fix Samba 3 to handle reads/writes over 127K (and remove the cifs mount
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restriction of wsize max being 127K)
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KNOWN BUGS (updated April 24, 2007)
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====================================
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See http://bugzilla.samba.org - search on product "CifsVFS" for
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current bug list.
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1) existing symbolic links (Windows reparse points) are recognized but
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can not be created remotely. They are implemented for Samba and those that
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support the CIFS Unix extensions, although earlier versions of Samba
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overly restrict the pathnames.
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2) follow_link and readdir code does not follow dfs junctions
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but recognizes them
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3) create of new files to FAT partitions on Windows servers can
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succeed but still return access denied (appears to be Windows
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server not cifs client problem) and has not been reproduced recently.
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NTFS partitions do not have this problem.
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4) Unix/POSIX capabilities are reset after reconnection, and affect
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a few fields in the tree connection but we do do not know which
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superblocks to apply these changes to. We should probably walk
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the list of superblocks to set these. Also need to check the
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flags on the second mount to the same share, and see if we
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can do the same trick that NFS does to remount duplicate shares.
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Misc testing to do
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==================
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1) check out max path names and max path name components against various server
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types. Try nested symlinks (8 deep). Return max path name in stat -f information
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2) Modify file portion of ltp so it can run against a mounted network
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share and run it against cifs vfs in automated fashion.
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3) Additional performance testing and optimization using iozone and similar -
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there are some easy changes that can be done to parallelize sequential writes,
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and when signing is disabled to request larger read sizes (larger than
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negotiated size) and send larger write sizes to modern servers.
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4) More exhaustively test against less common servers. More testing
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against Windows 9x, Windows ME servers.
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