Based on kernel version 4.2. Page generated on 2015-09-09 12:13 EST.
1 Version 2.03 August 1, 2014 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) SMB3 (and SMB3.02) missing optional features: 11 - RDMA 12 - multichannel (started) 13 - directory leases (improved metadata caching) 14 - T10 copy offload (copy chunk is only mechanism supported) 15 - encrypted shares 16 17 b) improved sparse file support 18 19 c) Directory entry caching relies on a 1 second timer, rather than 20 using FindNotify or equivalent. - (started) 21 22 d) quota support (needs minor kernel change since quota calls 23 to make it to network filesystems or deviceless filesystems) 24 25 e) improve support for very old servers (OS/2 and Win9x for example) 26 Including support for changing the time remotely (utimes command). 27 28 f) hook lower into the sockets api (as NFS/SunRPC does) to avoid the 29 extra copy in/out of the socket buffers in some cases. 30 31 g) Better optimize open (and pathbased setfilesize) to reduce the 32 oplock breaks coming from windows srv. Piggyback identical file 33 opens on top of each other by incrementing reference count rather 34 than resending (helps reduce server resource utilization and avoid 35 spurious oplock breaks). 36 37 h) Add support for storing symlink info to Windows servers 38 in the Extended Attribute format their SFU clients would recognize. 39 40 i) Finish inotify support so kde and gnome file list windows 41 will autorefresh (partially complete by Asser). Needs minor kernel 42 vfs change to support removing D_NOTIFY on a file. 43 44 j) Add GUI tool to configure /proc/fs/cifs settings and for display of 45 the CIFS statistics (started) 46 47 k) implement support for security and trusted categories of xattrs 48 (requires minor protocol extension) to enable better support for SELINUX 49 50 l) Implement O_DIRECT flag on open (already supported on mount) 51 52 m) Create UID mapping facility so server UIDs can be mapped on a per 53 mount or a per server basis to client UIDs or nobody if no mapping 54 exists. This is helpful when Unix extensions are negotiated to 55 allow better permission checking when UIDs differ on the server 56 and client. Add new protocol request to the CIFS protocol 57 standard for asking the server for the corresponding name of a 58 particular uid. 59 60 n) DOS attrs - returned as pseudo-xattr in Samba format (check VFAT and NTFS for this too) 61 62 o) mount check for unmatched uids 63 64 p) Add support for new vfs entry point for fallocate 65 66 q) Add tools to take advantage of cifs/smb3 specific ioctls and features 67 such as "CopyChunk" (fast server side file copy) 68 69 r) encrypted file support 70 71 s) improved stats gathering, tools (perhaps integration with nfsometer?) 72 73 t) allow setting more NTFS/SMB3 file attributes remotely (currently limited to compressed 74 file attribute via chflags) 75 76 u) mount helper GUI (to simplify the various configuration options on mount) 77 78 79 KNOWN BUGS 80 ==================================== 81 See http://bugzilla.samba.org - search on product "CifsVFS" for 82 current bug list. Also check http://bugzilla.kernel.org (Product = File System, Component = CIFS) 83 84 1) existing symbolic links (Windows reparse points) are recognized but 85 can not be created remotely. They are implemented for Samba and those that 86 support the CIFS Unix extensions, although earlier versions of Samba 87 overly restrict the pathnames. 88 2) follow_link and readdir code does not follow dfs junctions 89 but recognizes them 90 91 Misc testing to do 92 ================== 93 1) check out max path names and max path name components against various server 94 types. Try nested symlinks (8 deep). Return max path name in stat -f information 95 96 2) Improve xfstest's cifs enablement and adapt xfstests where needed to test 97 cifs better 98 99 3) Additional performance testing and optimization using iozone and similar - 100 there are some easy changes that can be done to parallelize sequential writes, 101 and when signing is disabled to request larger read sizes (larger than 102 negotiated size) and send larger write sizes to modern servers. 103 104 4) More exhaustively test against less common servers