[11/11] cifs: Support fscache indexing rewrite

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 #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/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
---

 fs/cifs/Kconfig    |    2 
 fs/cifs/Makefile   |    2 
 fs/cifs/cache.c    |  105 ----------------
 fs/cifs/cifsfs.c   |   19 ++-
 fs/cifs/cifsglob.h |    5 -
 fs/cifs/connect.c  |   15 --
 fs/cifs/dir.c      |    5 +
 fs/cifs/file.c     |   70 +++++++----
 fs/cifs/fscache.c  |  333 ++++++++++++----------------------------------------
 fs/cifs/fscache.h  |  126 ++++++--------------
 fs/cifs/inode.c    |   19 ++-
 11 files changed, 197 insertions(+), 504 deletions(-)
 delete mode 100644 fs/cifs/cache.c

Message ID	164251411336.3435901.17077059669994001060.stgit@warthog.procyon.org.uk (mailing list archive)
State	New, archived
Headers	show Return-Path: <linux-nfs-owner@kernel.org> Organization: Red Hat UK Ltd. Registered Address: Red Hat UK Ltd, Amberley Place, 107-111 Peascod Street, Windsor, Berkshire, SI4 1TE, United Kingdom. Registered in England and Wales under Company Registration No. 3798903 Subject: [PATCH 11/11] cifs: Support fscache indexing rewrite From: David Howells <dhowells@redhat.com> To: linux-cachefs@redhat.com Cc: Jeff Layton <jlayton@kernel.org>, Steve French <smfrench@gmail.com>, Shyam Prasad N <nspmangalore@gmail.com>, linux-cifs@vger.kernel.org, dhowells@redhat.com, Trond Myklebust <trondmy@hammerspace.com>, Anna Schumaker <anna.schumaker@netapp.com>, Steve French <smfrench@gmail.com>, Dominique Martinet <asmadeus@codewreck.org>, Jeff Layton <jlayton@kernel.org>, Matthew Wilcox <willy@infradead.org>, Alexander Viro <viro@zeniv.linux.org.uk>, Omar Sandoval <osandov@osandov.com>, JeffleXu <jefflexu@linux.alibaba.com>, Linus Torvalds <torvalds@linux-foundation.org>, linux-afs@lists.infradead.org, linux-nfs@vger.kernel.org, linux-cifs@vger.kernel.org, ceph-devel@vger.kernel.org, v9fs-developer@lists.sourceforge.net, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org Date: Tue, 18 Jan 2022 13:55:13 +0000 Message-ID: <164251411336.3435901.17077059669994001060.stgit@warthog.procyon.org.uk> In-Reply-To: <164251396932.3435901.344517748027321142.stgit@warthog.procyon.org.uk> References: <164251396932.3435901.344517748027321142.stgit@warthog.procyon.org.uk> User-Agent: StGit/0.23 MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Precedence: bulk
Series	fscache, cachefiles: Rewrite fixes/updates \| expand [00/11] fscache, cachefiles: Rewrite fixes/updates [01/11] fscache: Fix the volume collision wait condition [02/11] cachefiles: Calculate the blockshift in terms of bytes, not pages [03/11] cachefiles: set default tag name if it's unspecified [04/11] cachefiles: Make some tracepoint adjustments [05/11] cachefiles: Trace active-mark failure [06/11] cachefiles: Explain checks in a comment [07/11] cachefiles: Check that the backing filesystem supports tmpfiles [08/11] fscache: Add a comment explaining how page-release optimisation works [09/11] vfs, fscache: Add an IS_KERNEL_FILE() macro for the S_KERNEL_FILE flag [10/11] netfs: Make ops->init_rreq() optional [11/11] cifs: Support fscache indexing rewrite

[11/11] cifs: Support fscache indexing rewrite

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