136 lines
5.8 KiB
ReStructuredText
136 lines
5.8 KiB
ReStructuredText
====
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TODO
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====
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Version 2.14 December 21, 2018
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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) SMB3 (and SMB3.1.1) missing optional features:
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- multichannel (partially integrated), integration of multichannel with RDMA
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- directory leases (improved metadata caching). Currently only implemented for root dir
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- T10 copy offload ie "ODX" (copy chunk, and "Duplicate Extents" ioctl
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currently the only two server side copy mechanisms supported)
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b) improved sparse file support (fiemap and SEEK_HOLE are implemented
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but additional features would be supportable by the protocol such
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as FALLOC_FL_COLLAPSE_RANGE and FALLOC_FL_INSERT_RANGE)
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c) Directory entry caching relies on a 1 second timer, rather than
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using Directory Leases, currently only the root file handle is cached longer
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by leveraging Directory Leases
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d) quota support (needs minor kernel change since quota calls otherwise
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won't make it to network filesystems or deviceless filesystems).
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e) Additional use cases can be optimized to use "compounding" (e.g.
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open/query/close and open/setinfo/close) to reduce the number of
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roundtrips to the server and improve performance. Various cases
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(stat, statfs, create, unlink, mkdir, xattrs) already have been improved by
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using compounding but more can be done. In addition we could
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significantly reduce redundant opens by using deferred close (with
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handle caching leases) and better using reference counters on file
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handles.
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f) Finish inotify 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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g) 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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h) 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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i) Add support for tree connect contexts (see MS-SMB2) a new SMB3.1.1 protocol
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feature (may be especially useful for virtualization).
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j) 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. Also better integration with winbind for resolving SID owners
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k) Add tools to take advantage of more smb3 specific ioctls and features
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(passthrough ioctl/fsctl is now implemented in cifs.ko to allow
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sending various SMB3 fsctls and query info and set info calls
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directly from user space) Add tools to make setting various non-POSIX
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metadata attributes easier from tools (e.g. extending what was done
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in smb-info tool).
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l) encrypted file support (currently the attribute showing the file is
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encrypted on the server is reported, but changing the attribute is not
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supported).
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m) improved stats gathering tools (perhaps integration with nfsometer?)
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to extend and make easier to use what is currently in /proc/fs/cifs/Stats
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n) Add support for claims based ACLs ("DAC")
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o) mount helper GUI (to simplify the various configuration options on mount)
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p) Expand support for witness protocol to allow for notification of share
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move, and server network adapter changes. Currently only notifications by
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the witness protocol for server move is supported by the Linux client.
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q) Allow mount.cifs to be more verbose in reporting errors with dialect
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or unsupported feature errors. This would now be easier due to the
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implementation of the new mount API.
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r) updating cifs documentation, and user guide.
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s) Addressing bugs found by running a broader set of xfstests in standard
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file system xfstest suite.
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t) split cifs and smb3 support into separate modules so legacy (and less
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secure) CIFS dialect can be disabled in environments that don't need it
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and simplify the code.
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v) Additional testing of POSIX Extensions for SMB3.1.1
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w) Add support for additional strong encryption types, and additional spnego
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authentication mechanisms (see MS-SMB2). GCM-256 is now partially implemented.
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x) Finish support for SMB3.1.1 compression
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Known Bugs
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==========
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See https://bugzilla.samba.org - search on product "CifsVFS" for
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current bug list. Also check http://bugzilla.kernel.org (Product = File System, Component = CIFS)
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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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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) Improve xfstest's cifs/smb3 enablement and adapt xfstests where needed to test
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cifs/smb3 better
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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
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5) Continue to extend the smb3 "buildbot" which does automated xfstesting
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against Windows, Samba and Azure currently - to add additional tests and
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to allow the buildbot to execute the tests faster. The URL for the
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buildbot is: http://smb3-test-rhel-75.southcentralus.cloudapp.azure.com
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6) Address various coverity warnings (most are not bugs per-se, but
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the more warnings are addressed, the easier it is to spot real
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problems that static analyzers will point out in the future).
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