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From: Marc Dionne <marc.c.dionne@gmail.com>
To: David Howells <dhowells@redhat.com>
Cc: linux-fsdevel@vger.kernel.org, linux-mm@kvack.org,
	linux-cifs@vger.kernel.org,
	Alexander Viro <viro@zeniv.linux.org.uk>,
	Mike Marshall <hubcap@omnibond.com>,
	linux-afs@lists.infradead.org,
	v9fs-developer@lists.sourceforge.net,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Christoph Hellwig <hch@lst.de>, Jeff Layton <jlayton@redhat.com>,
	linux-nfs@vger.kernel.org, linux-cachefs@redhat.com,
	ceph-devel@vger.kernel.org,
	"Matthew Wilcox (Oracle)" <willy@infradead.org>,
	Trond Myklebust <trond.myklebust@hammerspace.com>,
	Anna Schumaker <anna.schumaker@netapp.com>,
	Steve French <sfrench@samba.org>,
	Dominique Martinet <asmadeus@codewreck.org>,
	David Wysochanski <dwysocha@redhat.com>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v6 00/30] Network fs helper library & fscache kiocb API
Date: Tue, 13 Apr 2021 13:21:52 -0300	[thread overview]
Message-ID: <CAB9dFdug7J0ygzW8-yq8EpYv6OG2zAmTeptHzQfZfnu5cwrqiQ@mail.gmail.com> (raw)
In-Reply-To: <161789062190.6155.12711584466338493050.stgit@warthog.procyon.org.uk>

On Thu, Apr 8, 2021 at 11:04 AM David Howells <dhowells@redhat.com> wrote:
>
>
> Here's a set of patches to do two things:
>
>  (1) Add a helper library to handle the new VM readahead interface.  This
>      is intended to be used unconditionally by the filesystem (whether or
>      not caching is enabled) and provides a common framework for doing
>      caching, transparent huge pages and, in the future, possibly fscrypt
>      and read bandwidth maximisation.  It also allows the netfs and the
>      cache to align, expand and slice up a read request from the VM in
>      various ways; the netfs need only provide a function to read a stretch
>      of data to the pagecache and the helper takes care of the rest.
>
>  (2) Add an alternative fscache/cachfiles I/O API that uses the kiocb
>      facility to do async DIO to transfer data to/from the netfs's pages,
>      rather than using readpage with wait queue snooping on one side and
>      vfs_write() on the other.  It also uses less memory, since it doesn't
>      do buffered I/O on the backing file.
>
>      Note that this uses SEEK_HOLE/SEEK_DATA to locate the data available
>      to be read from the cache.  Whilst this is an improvement from the
>      bmap interface, it still has a problem with regard to a modern
>      extent-based filesystem inserting or removing bridging blocks of
>      zeros.  Fixing that requires a much greater overhaul.
>
> This is a step towards overhauling the fscache API.  The change is opt-in
> on the part of the network filesystem.  A netfs should not try to mix the
> old and the new API because of conflicting ways of handling pages and the
> PG_fscache page flag and because it would be mixing DIO with buffered I/O.
> Further, the helper library can't be used with the old API.
>
> This does not change any of the fscache cookie handling APIs or the way
> invalidation is done.
>
> In the near term, I intend to deprecate and remove the old I/O API
> (fscache_allocate_page{,s}(), fscache_read_or_alloc_page{,s}(),
> fscache_write_page() and fscache_uncache_page()) and eventually replace
> most of fscache/cachefiles with something simpler and easier to follow.
>
> The patchset contains the following parts:
>
>  (1) Some helper patches, including provision of an ITER_XARRAY iov
>      iterator and a function to do readahead expansion.
>
>  (2) Patches to add the netfs helper library.
>
>  (3) A patch to add the fscache/cachefiles kiocb API.
>
>  (4) Patches to add support in AFS for this.
>
> Jeff Layton has patches to add support in Ceph for this.
>
> With this, AFS without a cache passes all expected xfstests; with a cache,
> there's an extra failure, but that's also there before these patches.
> Fixing that probably requires a greater overhaul.  Ceph also passes the
> expected tests.
>
> The netfs lib and fscache/cachefiles patches can be found also on:
>
>         https://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs.git/log/?h=netfs-lib
>
> The afs patches can be found on:
>
>         https://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs.git/log/?h=afs-netfs-lib
>
>
> Changes
> =======
>
> ver #6:
>       Merged in some fixes and added an additional tracepoint[8], including
>       fixing the amalgamation of contiguous subrequests that are to be
>       written to the cache.
>
>       Added/merged some patches from Matthew Wilcox to make
>       readahead_expand() appropriately adjust the trigger for the next
>       readahead[9].  Also included is a patch to kerneldocify the
>       file_ra_state struct.
>
>       Altered netfs_write_begin() to use DEFINE_READAHEAD()[10].
>
>       Split the afs patches out into their own branch.
>
> ver #5:
>       Fixed some review comments from Matthew Wilcox:
>
>       - Put a comment into netfs_readahead() to indicate why there's a loop
>         that puts, but doesn't unlock, "unconsumed" pages at the end when
>         it could just return said pages to the caller to dispose of[6].
>         (This is because where those pages are marked consumed).
>
>       - Use the page_file_mapping() and page_index() helper functions
>         rather than accessing the page struct directly[6].
>
>       - Better names for wrangling functions for PG_private_2 and
>         PG_fscache wrangling functions[7].  Came up with
>         {set,end,wait_for}_page_private_2() and aliased these for fscache.
>
>       Moved the taking of/dropping a page ref for the PG_private_2 flag
>       into the set and end functions.
>
> ver #4:
>       Fixed some review comments from Christoph Hellwig, including dropping
>       the export of rw_verify_area()[3] and some minor stuff[4].
>
>       Moved the declaration of readahead_expand() to a better location[5].
>
>       Rebased to v5.12-rc2 and added a bunch of references into individual
>       commits.
>
>       Dropped Ceph support - that will go through the maintainer's tree.
>
>       Added interface documentation for the netfs helper library.
>
> ver #3:
>       Rolled in the bug fixes.
>
>       Adjusted the functions that unlock and wait for PG_fscache according
>       to Linus's suggestion[1].
>
>       Hold a ref on a page when PG_fscache is set as per Linus's
>       suggestion[2].
>
>       Dropped NFS support and added Ceph support.
>
> ver #2:
>       Fixed some bugs and added NFS support.
>
> Link: https://lore.kernel.org/r/CAHk-=wh+2gbF7XEjYc=HV9w_2uVzVf7vs60BPz0gFA=+pUm3ww@mail.gmail.com/ [1]
> Link: https://lore.kernel.org/r/CAHk-=wjgA-74ddehziVk=XAEMTKswPu1Yw4uaro1R3ibs27ztw@mail.gmail.com/ [2]
> Link: https://lore.kernel.org/r/20210216102614.GA27555@lst.de/ [3]
> Link: https://lore.kernel.org/r/20210216084230.GA23669@lst.de/ [4]
> Link: https://lore.kernel.org/r/20210217161358.GM2858050@casper.infradead.org/ [5]
> Link: https://lore.kernel.org/r/20210321014202.GF3420@casper.infradead.org/ [6]
> Link: https://lore.kernel.org/r/20210321105309.GG3420@casper.infradead.org/ [7]
> Link: https://lore.kernel.org/r/161781041339.463527.18139104281901492882.stgit@warthog.procyon.org.uk/ [8]
> Link: https://lore.kernel.org/r/20210407201857.3582797-1-willy@infradead.org/ [9]
> Link: https://lore.kernel.org/r/1234933.1617886271@warthog.procyon.org.uk/ [10]
>
> References
> ==========
>
> These patches have been published for review before, firstly as part of a
> larger set:
>
> Link: https://lore.kernel.org/r/158861203563.340223.7585359869938129395.stgit@warthog.procyon.org.uk/
>
> Link: https://lore.kernel.org/r/159465766378.1376105.11619976251039287525.stgit@warthog.procyon.org.uk/
> Link: https://lore.kernel.org/r/159465784033.1376674.18106463693989811037.stgit@warthog.procyon.org.uk/
> Link: https://lore.kernel.org/r/159465821598.1377938.2046362270225008168.stgit@warthog.procyon.org.uk/
>
> Link: https://lore.kernel.org/r/160588455242.3465195.3214733858273019178.stgit@warthog.procyon.org.uk/
>
> Then as a cut-down set:
>
> Link: https://lore.kernel.org/r/161118128472.1232039.11746799833066425131.stgit@warthog.procyon.org.uk/ # v1
>
> Link: https://lore.kernel.org/r/161161025063.2537118.2009249444682241405.stgit@warthog.procyon.org.uk/ # v2
>
> Link: https://lore.kernel.org/r/161340385320.1303470.2392622971006879777.stgit@warthog.procyon.org.uk/ # v3
>
> Link: https://lore.kernel.org/r/161539526152.286939.8589700175877370401.stgit@warthog.procyon.org.uk/ # v4
>
> Link: https://lore.kernel.org/r/161653784755.2770958.11820491619308713741.stgit@warthog.procyon.org.uk/ # v5
>
> Proposals/information about the design has been published here:
>
> Link: https://lore.kernel.org/r/24942.1573667720@warthog.procyon.org.uk/
> Link: https://lore.kernel.org/r/2758811.1610621106@warthog.procyon.org.uk/
> Link: https://lore.kernel.org/r/1441311.1598547738@warthog.procyon.org.uk/
> Link: https://lore.kernel.org/r/160655.1611012999@warthog.procyon.org.uk/
>
> And requests for information:
>
> Link: https://lore.kernel.org/r/3326.1579019665@warthog.procyon.org.uk/
> Link: https://lore.kernel.org/r/4467.1579020509@warthog.procyon.org.uk/
> Link: https://lore.kernel.org/r/3577430.1579705075@warthog.procyon.org.uk/
>
> I've posted partial patches to try and help 9p and cifs along:
>
> Link: https://lore.kernel.org/r/1514086.1605697347@warthog.procyon.org.uk/
> Link: https://lore.kernel.org/r/1794123.1605713481@warthog.procyon.org.uk/
> Link: https://lore.kernel.org/r/241017.1612263863@warthog.procyon.org.uk/
> Link: https://lore.kernel.org/r/270998.1612265397@warthog.procyon.org.uk/
>
> David
> ---
> David Howells (28):
>       iov_iter: Add ITER_XARRAY
>       mm: Add set/end/wait functions for PG_private_2
>       mm: Implement readahead_control pageset expansion
>       netfs: Make a netfs helper module
>       netfs: Documentation for helper library
>       netfs, mm: Move PG_fscache helper funcs to linux/netfs.h
>       netfs, mm: Add set/end/wait_on_page_fscache() aliases
>       netfs: Provide readahead and readpage netfs helpers
>       netfs: Add tracepoints
>       netfs: Gather stats
>       netfs: Add write_begin helper
>       netfs: Define an interface to talk to a cache
>       netfs: Add a tracepoint to log failures that would be otherwise unseen
>       fscache, cachefiles: Add alternate API to use kiocb for read/write to cache
>       afs: Disable use of the fscache I/O routines
>       afs: Pass page into dirty region helpers to provide THP size
>       afs: Print the operation debug_id when logging an unexpected data version
>       afs: Move key to afs_read struct
>       afs: Don't truncate iter during data fetch
>       afs: Log remote unmarshalling errors
>       afs: Set up the iov_iter before calling afs_extract_data()
>       afs: Use ITER_XARRAY for writing
>       afs: Wait on PG_fscache before modifying/releasing a page
>       afs: Extract writeback extension into its own function
>       afs: Prepare for use of THPs
>       afs: Use the fs operation ops to handle FetchData completion
>       afs: Use new netfs lib read helper API
>       afs: Use the netfs_write_begin() helper
>
> Matthew Wilcox (Oracle) (2):
>       mm/filemap: Pass the file_ra_state in the ractl
>       fs: Document file_ra_state
>
>
>  Documentation/filesystems/index.rst         |    1 +
>  Documentation/filesystems/netfs_library.rst |  526 ++++++++
>  fs/Kconfig                                  |    1 +
>  fs/Makefile                                 |    1 +
>  fs/afs/Kconfig                              |    1 +
>  fs/afs/dir.c                                |  225 ++--
>  fs/afs/file.c                               |  483 ++------
>  fs/afs/fs_operation.c                       |    4 +-
>  fs/afs/fsclient.c                           |  108 +-
>  fs/afs/inode.c                              |    7 +-
>  fs/afs/internal.h                           |   59 +-
>  fs/afs/rxrpc.c                              |  150 +--
>  fs/afs/write.c                              |  657 +++++-----
>  fs/afs/yfsclient.c                          |   82 +-
>  fs/cachefiles/Makefile                      |    1 +
>  fs/cachefiles/interface.c                   |    5 +-
>  fs/cachefiles/internal.h                    |    9 +
>  fs/cachefiles/io.c                          |  420 +++++++
>  fs/ext4/verity.c                            |    2 +-
>  fs/f2fs/file.c                              |    2 +-
>  fs/f2fs/verity.c                            |    2 +-
>  fs/fscache/Kconfig                          |    1 +
>  fs/fscache/Makefile                         |    1 +
>  fs/fscache/internal.h                       |    4 +
>  fs/fscache/io.c                             |  116 ++
>  fs/fscache/page.c                           |    2 +-
>  fs/fscache/stats.c                          |    1 +
>  fs/netfs/Kconfig                            |   23 +
>  fs/netfs/Makefile                           |    5 +
>  fs/netfs/internal.h                         |   97 ++
>  fs/netfs/read_helper.c                      | 1185 +++++++++++++++++++
>  fs/netfs/stats.c                            |   59 +
>  include/linux/fs.h                          |   24 +-
>  include/linux/fscache-cache.h               |    4 +
>  include/linux/fscache.h                     |   50 +-
>  include/linux/netfs.h                       |  234 ++++
>  include/linux/pagemap.h                     |   41 +-
>  include/net/af_rxrpc.h                      |    2 +-
>  include/trace/events/afs.h                  |   74 +-
>  include/trace/events/netfs.h                |  261 ++++
>  mm/filemap.c                                |   63 +-
>  mm/internal.h                               |    7 +-
>  mm/readahead.c                              |   97 +-
>  net/rxrpc/recvmsg.c                         |    9 +-
>  44 files changed, 3998 insertions(+), 1108 deletions(-)
>  create mode 100644 Documentation/filesystems/netfs_library.rst
>  create mode 100644 fs/cachefiles/io.c
>  create mode 100644 fs/fscache/io.c
>  create mode 100644 fs/netfs/Kconfig
>  create mode 100644 fs/netfs/Makefile
>  create mode 100644 fs/netfs/internal.h
>  create mode 100644 fs/netfs/read_helper.c
>  create mode 100644 fs/netfs/stats.c
>  create mode 100644 include/linux/netfs.h
>  create mode 100644 include/trace/events/netfs.h
>
>

You can add:
Tested-By: Marc Dionne <marc.dionne@auristor.com>

for the series, including the afs changes.  Ran it through automated
testing that does kernel builds in an AFS mount, both with and without
cachefilesd running.

Marc

  parent reply	other threads:[~2021-04-13 16:23 UTC|newest]

Thread overview: 68+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-04-08 14:03 David Howells
2021-04-08 14:04 ` [PATCH v6 01/30] iov_iter: Add ITER_XARRAY David Howells
2021-04-09  1:24   ` Al Viro
2021-04-09 18:10     ` [RFC PATCH 1/2] iov_iter: Remove iov_iter_for_each_range() David Howells
2021-04-09 18:11     ` [RFC PATCH 2/2] iov_iter: Drop the X argument from iterate_all_kinds() and use B instead David Howells
2021-04-09  9:09   ` [PATCH v6 01/30] iov_iter: Add ITER_XARRAY David Howells
2021-04-09 11:44     ` Matthew Wilcox
2021-04-22 13:35   ` Jeff Layton
2021-04-22 13:35     ` Jeff Layton
2021-04-22 13:51   ` David Howells
2021-04-22 14:51     ` Jeff Layton
2021-04-22 14:51       ` Jeff Layton
2021-04-08 14:04 ` [PATCH v6 02/30] mm: Add set/end/wait functions for PG_private_2 David Howells
2021-04-08 14:50   ` Matthew Wilcox
2021-04-08 15:25   ` David Howells
2021-04-08 15:57   ` David Howells
2021-04-08 21:15   ` [RFC][PATCH] mm: Split page_has_private() in two to better handle PG_private_2 David Howells
2021-04-08 23:50     ` Linus Torvalds
2021-04-08 23:50       ` Linus Torvalds
2021-04-09 10:59       ` [RFC PATCH 1/3] Make the generic bitops return bool David Howells
2021-04-09 10:59       ` [RFC PATCH 2/3] mm: Return bool from pagebit test functions David Howells
2021-04-09 11:16         ` Matthew Wilcox
2021-04-09 12:00         ` David Howells
2021-04-09 12:35         ` David Howells
2021-04-09 16:03         ` David Howells
2021-04-09 16:03           ` David Howells
2021-04-09 10:59       ` [RFC PATCH 3/3] mm: Split page_has_private() in two to better handle PG_private_2 David Howells
2021-04-09 11:24         ` Matthew Wilcox
2021-04-09  8:14     ` [RFC][PATCH] " David Howells
2021-04-13 15:11   ` [PATCH v7] mm: Add set/end/wait functions for PG_private_2 David Howells
2021-04-13 15:22     ` Matthew Wilcox
2021-04-08 14:04 ` [PATCH v6 03/30] mm/filemap: Pass the file_ra_state in the ractl David Howells
2021-04-08 14:04 ` [PATCH v6 04/30] fs: Document file_ra_state David Howells
2021-04-08 14:04 ` [PATCH v6 05/30] mm: Implement readahead_control pageset expansion David Howells
2021-04-08 14:55   ` Matthew Wilcox
2021-04-08 14:05 ` [PATCH v6 06/30] netfs: Make a netfs helper module David Howells
2021-04-08 14:05 ` [PATCH v6 07/30] netfs: Documentation for helper library David Howells
2021-04-08 14:05 ` [PATCH v6 08/30] netfs, mm: Move PG_fscache helper funcs to linux/netfs.h David Howells
2021-04-08 14:05 ` [PATCH v6 09/30] netfs, mm: Add set/end/wait_on_page_fscache() aliases David Howells
2021-04-08 14:06 ` [PATCH v6 10/30] netfs: Provide readahead and readpage netfs helpers David Howells
2021-04-08 14:06 ` [PATCH v6 11/30] netfs: Add tracepoints David Howells
2021-04-08 14:06 ` [PATCH v6 12/30] netfs: Gather stats David Howells
2021-04-08 14:06 ` [PATCH v6 13/30] netfs: Add write_begin helper David Howells
2021-04-08 14:06 ` [PATCH v6 14/30] netfs: Define an interface to talk to a cache David Howells
2021-04-08 14:07 ` [PATCH v6 15/30] netfs: Add a tracepoint to log failures that would be otherwise unseen David Howells
2021-04-08 14:07 ` [PATCH v6 16/30] fscache, cachefiles: Add alternate API to use kiocb for read/write to cache David Howells
2021-04-08 14:07 ` [PATCH v6 17/30] afs: Disable use of the fscache I/O routines David Howells
2021-04-08 14:07 ` [PATCH v6 18/30] afs: Pass page into dirty region helpers to provide THP size David Howells
2021-04-08 14:08 ` [PATCH v6 19/30] afs: Print the operation debug_id when logging an unexpected data version David Howells
2021-04-08 14:08 ` [PATCH v6 20/30] afs: Move key to afs_read struct David Howells
2021-04-08 14:08 ` [PATCH v6 21/30] afs: Don't truncate iter during data fetch David Howells
2021-04-08 14:08 ` [PATCH v6 22/30] afs: Log remote unmarshalling errors David Howells
2021-04-08 14:08 ` [PATCH v6 23/30] afs: Set up the iov_iter before calling afs_extract_data() David Howells
2021-04-08 14:09 ` [PATCH v6 24/30] afs: Use ITER_XARRAY for writing David Howells
2021-04-08 14:09 ` [PATCH v6 25/30] afs: Wait on PG_fscache before modifying/releasing a page David Howells
2021-04-08 14:09 ` [PATCH v6 26/30] afs: Extract writeback extension into its own function David Howells
2021-04-08 14:09 ` [PATCH v6 27/30] afs: Prepare for use of THPs David Howells
2021-04-08 14:09 ` [PATCH v6 28/30] afs: Use the fs operation ops to handle FetchData completion David Howells
2021-04-08 14:10 ` [PATCH v6 29/30] afs: Use new netfs lib read helper API David Howells
2021-04-08 14:10 ` [PATCH v6 30/30] afs: Use the netfs_write_begin() helper David Howells
2021-04-08 15:40 ` [PATCH v6 00/30] Network fs helper library & fscache kiocb API Jeff Layton
2021-04-08 15:40   ` Jeff Layton
2021-04-09 12:04 ` David Wysochanski
2021-04-09 12:04   ` David Wysochanski
2021-04-13 14:56   ` David Wysochanski
2021-04-13 14:56     ` David Wysochanski
2021-04-13 16:21 ` Marc Dionne [this message]
2021-04-13 16:21   ` Marc Dionne

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