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70431bfd82
Change the cifs filesystem to take account of the changes to fscache's
indexing rewrite and reenable caching in cifs.
The following changes have been made:
(1) The fscache_netfs struct is no more, and there's no need to register
the filesystem as a whole.
(2) The session cookie is now an fscache_volume cookie, allocated with
fscache_acquire_volume(). That takes three parameters: a string
representing the "volume" in the index, a string naming the cache to
use (or NULL) and a u64 that conveys coherency metadata for the
volume.
For cifs, I've made it render the volume name string as:
"cifs,<ipaddress>,<sharename>"
where the sharename has '/' characters replaced with ';'.
This probably needs rethinking a bit as the total name could exceed
the maximum filename component length.
Further, the coherency data is currently just set to 0. It needs
something else doing with it - I wonder if it would suffice simply to
sum the resource_id, vol_create_time and vol_serial_number or maybe
hash them.
(3) The fscache_cookie_def is no more and needed information is passed
directly to fscache_acquire_cookie(). The cache no longer calls back
into the filesystem, but rather metadata changes are indicated at
other times.
fscache_acquire_cookie() is passed the same keying and coherency
information as before.
(4) The functions to set/reset cookies are removed and
fscache_use_cookie() and fscache_unuse_cookie() are used instead.
fscache_use_cookie() is passed a flag to indicate if the cookie is
opened for writing. fscache_unuse_cookie() is passed updates for the
metadata if we changed it (ie. if the file was opened for writing).
These are called when the file is opened or closed.
(5) cifs_setattr_*() are made to call fscache_resize() to change the size
of the cache object.
(6) The functions to read and write data are stubbed out pending a
conversion to use netfslib.
Changes
=======
ver #8:
- Abstract cache invalidation into a helper function.
- Fix some checkpatch warnings[3].
ver #7:
- Removed the accidentally added-back call to get the super cookie in
cifs_root_iget().
- Fixed the right call to cifs_fscache_get_super_cookie() to take account
of the "-o fsc" mount flag.
ver #6:
- Moved the change of gfpflags_allow_blocking() to current_is_kswapd() for
cifs here.
- Fixed one of the error paths in cifs_atomic_open() to jump around the
call to use the cookie.
- Fixed an additional successful return in the middle of cifs_open() to
use the cookie on the way out.
- Only get a volume cookie (and thus inode cookies) when "-o fsc" is
supplied to mount.
ver #5:
- Fixed a couple of bits of cookie handling[2]:
- The cookie should be released in cifs_evict_inode(), not
cifsFileInfo_put_final(). The cookie needs to persist beyond file
closure so that writepages will be able to write to it.
- fscache_use_cookie() needs to be called in cifs_atomic_open() as it is
for cifs_open().
ver #4:
- Fixed the use of sizeof with memset.
- tcon->vol_create_time is __le64 so doesn't need cpu_to_le64().
ver #3:
- Canonicalise the cifs coherency data to make the cache portable.
- Set volume coherency data.
ver #2:
- Use gfpflags_allow_blocking() rather than using flag directly.
- Upgraded to -rc4 to allow for upstream changes[1].
- fscache_acquire_volume() now returns errors.
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Jeff Layton <jlayton@kernel.org>
cc: Steve French <smfrench@gmail.com>
cc: Shyam Prasad N <nspmangalore@gmail.com>
cc: linux-cifs@vger.kernel.org
cc: linux-cachefs@redhat.com
Link: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=23b55d673d7527b093cd97b7c217c82e70cd1af0 [1]
Link: https://lore.kernel.org/r/3419813.1641592362@warthog.procyon.org.uk/ [2]
Link: https://lore.kernel.org/r/CAH2r5muTanw9pJqzAHd01d9A8keeChkzGsCEH6=0rHutVLAF-A@mail.gmail.com/ [3]
Link: https://lore.kernel.org/r/163819671009.215744.11230627184193298714.stgit@warthog.procyon.org.uk/ # v1
Link: https://lore.kernel.org/r/163906982979.143852.10672081929614953210.stgit@warthog.procyon.org.uk/ # v2
Link: https://lore.kernel.org/r/163967187187.1823006.247415138444991444.stgit@warthog.procyon.org.uk/ # v3
Link: https://lore.kernel.org/r/164021579335.640689.2681324337038770579.stgit@warthog.procyon.org.uk/ # v4
Link: https://lore.kernel.org/r/3462849.1641593783@warthog.procyon.org.uk/ # v5
Link: https://lore.kernel.org/r/1318953.1642024578@warthog.procyon.org.uk/ # v6
Signed-off-by: Steve French <stfrench@microsoft.com>
204 lines
7.7 KiB
Plaintext
204 lines
7.7 KiB
Plaintext
# SPDX-License-Identifier: GPL-2.0-only
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config CIFS
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tristate "SMB3 and CIFS support (advanced network filesystem)"
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depends on INET
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select NLS
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select CRYPTO
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select CRYPTO_MD5
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select CRYPTO_SHA256
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select CRYPTO_SHA512
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select CRYPTO_CMAC
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select CRYPTO_HMAC
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select CRYPTO_AEAD2
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select CRYPTO_CCM
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select CRYPTO_GCM
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select CRYPTO_ECB
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select CRYPTO_AES
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select KEYS
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select DNS_RESOLVER
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select ASN1
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select OID_REGISTRY
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help
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This is the client VFS module for the SMB3 family of NAS protocols,
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(including support for the most recent, most secure dialect SMB3.1.1)
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as well as for earlier dialects such as SMB2.1, SMB2 and the older
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Common Internet File System (CIFS) protocol. CIFS was the successor
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to the original dialect, the Server Message Block (SMB) protocol, the
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native file sharing mechanism for most early PC operating systems.
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The SMB3 protocol is supported by most modern operating systems
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and NAS appliances (e.g. Samba, Windows 10, Windows Server 2016,
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MacOS) and even in the cloud (e.g. Microsoft Azure).
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The older CIFS protocol was included in Windows NT4, 2000 and XP (and
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later) as well by Samba (which provides excellent CIFS and SMB3
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server support for Linux and many other operating systems). Use of
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dialects older than SMB2.1 is often discouraged on public networks.
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This module also provides limited support for OS/2 and Windows ME
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and similar very old servers.
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This module provides an advanced network file system client
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for mounting to SMB3 (and CIFS) compliant servers. It includes
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support for DFS (hierarchical name space), secure per-user
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session establishment via Kerberos or NTLM or NTLMv2, RDMA
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(smbdirect), advanced security features, per-share encryption,
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directory leases, safe distributed caching (oplock), optional packet
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signing, Unicode and other internationalization improvements.
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In general, the default dialects, SMB3 and later, enable better
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performance, security and features, than would be possible with CIFS.
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Note that when mounting to Samba, due to the CIFS POSIX extensions,
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CIFS mounts can provide slightly better POSIX compatibility
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than SMB3 mounts. SMB2/SMB3 mount options are also
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slightly simpler (compared to CIFS) due to protocol improvements.
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If you need to mount to Samba, Azure, Macs or Windows from this machine, say Y.
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config CIFS_STATS2
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bool "Extended statistics"
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depends on CIFS
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default y
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help
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Enabling this option will allow more detailed statistics on SMB
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request timing to be displayed in /proc/fs/cifs/DebugData and also
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allow optional logging of slow responses to dmesg (depending on the
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value of /proc/fs/cifs/cifsFYI). See Documentation/admin-guide/cifs/usage.rst
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for more details. These additional statistics may have a minor effect
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on performance and memory utilization.
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If unsure, say Y.
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config CIFS_ALLOW_INSECURE_LEGACY
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bool "Support legacy servers which use less secure dialects"
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depends on CIFS
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default y
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help
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Modern dialects, SMB2.1 and later (including SMB3 and 3.1.1), have
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additional security features, including protection against
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man-in-the-middle attacks and stronger crypto hashes, so the use
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of legacy dialects (SMB1/CIFS and SMB2.0) is discouraged.
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Disabling this option prevents users from using vers=1.0 or vers=2.0
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on mounts with cifs.ko
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If unsure, say Y.
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config CIFS_UPCALL
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bool "Kerberos/SPNEGO advanced session setup"
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depends on CIFS
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help
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Enables an upcall mechanism for CIFS which accesses userspace helper
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utilities to provide SPNEGO packaged (RFC 4178) Kerberos tickets
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which are needed to mount to certain secure servers (for which more
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secure Kerberos authentication is required). If unsure, say Y.
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config CIFS_XATTR
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bool "CIFS extended attributes"
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depends on CIFS
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help
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Extended attributes are name:value pairs associated with inodes by
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the kernel or by users (see the attr(5) manual page for details).
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CIFS maps the name of extended attributes beginning with the user
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namespace prefix to SMB/CIFS EAs. EAs are stored on Windows
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servers without the user namespace prefix, but their names are
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seen by Linux cifs clients prefaced by the user namespace prefix.
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The system namespace (used by some filesystems to store ACLs) is
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not supported at this time.
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If unsure, say Y.
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config CIFS_POSIX
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bool "CIFS POSIX Extensions"
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depends on CIFS && CIFS_ALLOW_INSECURE_LEGACY && CIFS_XATTR
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help
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Enabling this option will cause the cifs client to attempt to
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negotiate a newer dialect with servers, such as Samba 3.0.5
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or later, that optionally can handle more POSIX like (rather
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than Windows like) file behavior. It also enables
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support for POSIX ACLs (getfacl and setfacl) to servers
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(such as Samba 3.10 and later) which can negotiate
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CIFS POSIX ACL support. If unsure, say N.
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config CIFS_DEBUG
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bool "Enable CIFS debugging routines"
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default y
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depends on CIFS
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help
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Enabling this option adds helpful debugging messages to
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the cifs code which increases the size of the cifs module.
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If unsure, say Y.
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config CIFS_DEBUG2
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bool "Enable additional CIFS debugging routines"
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depends on CIFS_DEBUG
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help
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Enabling this option adds a few more debugging routines
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to the cifs code which slightly increases the size of
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the cifs module and can cause additional logging of debug
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messages in some error paths, slowing performance. This
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option can be turned off unless you are debugging
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cifs problems. If unsure, say N.
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config CIFS_DEBUG_DUMP_KEYS
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bool "Dump encryption keys for offline decryption (Unsafe)"
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depends on CIFS_DEBUG
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help
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Enabling this will dump the encryption and decryption keys
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used to communicate on an encrypted share connection on the
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console. This allows Wireshark to decrypt and dissect
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encrypted network captures. Enable this carefully.
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If unsure, say N.
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config CIFS_DFS_UPCALL
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bool "DFS feature support"
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depends on CIFS
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help
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Distributed File System (DFS) support is used to access shares
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transparently in an enterprise name space, even if the share
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moves to a different server. This feature also enables
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an upcall mechanism for CIFS which contacts userspace helper
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utilities to provide server name resolution (host names to
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IP addresses) which is needed in order to reconnect to
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servers if their addresses change or for implicit mounts of
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DFS junction points. If unsure, say Y.
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config CIFS_SWN_UPCALL
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bool "SWN feature support"
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depends on CIFS
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help
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The Service Witness Protocol (SWN) is used to get notifications
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from a highly available server of resource state changes. This
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feature enables an upcall mechanism for CIFS which contacts a
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userspace daemon to establish the DCE/RPC connection to retrieve
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the cluster available interfaces and resource change notifications.
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If unsure, say Y.
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config CIFS_NFSD_EXPORT
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bool "Allow nfsd to export CIFS file system"
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depends on CIFS && BROKEN
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help
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Allows NFS server to export a CIFS mounted share (nfsd over cifs)
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config CIFS_SMB_DIRECT
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bool "SMB Direct support"
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depends on CIFS=m && INFINIBAND && INFINIBAND_ADDR_TRANS || CIFS=y && INFINIBAND=y && INFINIBAND_ADDR_TRANS=y
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help
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Enables SMB Direct support for SMB 3.0, 3.02 and 3.1.1.
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SMB Direct allows transferring SMB packets over RDMA. If unsure,
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say Y.
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config CIFS_FSCACHE
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bool "Provide CIFS client caching support"
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depends on CIFS=m && FSCACHE || CIFS=y && FSCACHE=y
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help
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Makes CIFS FS-Cache capable. Say Y here if you want your CIFS data
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to be cached locally on disk through the general filesystem cache
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manager. If unsure, say N.
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config CIFS_ROOT
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bool "SMB root file system (Experimental)"
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depends on CIFS=y && IP_PNP
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help
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Enables root file system support over SMB protocol.
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Most people say N here.
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