[PATCH net-next 00/12] fscache: Fixes, traces and development

From: David Howells
Date: Wed Apr 04 2018 - 18:06:48 EST



Hi Linus,

Here are some patches that fix some AFS's usage of fscache, two of which
conflict with later patches in this series, so I've included them here:

(1) Need to invalidate the cache if a foreign data change is detected on
the server.

(2) Move the vnode ID uniquifier (equivalent to i_generation) from the
auxiliary data to the index key to prevent a race between file delete
and a subsequent file create seeing the same index key.

(3) Need to retire cookies that correspond to files that we think got
deleted on the server.

There are some patches to fix some things in fscache and cachefiles:

(4) Fix a couple of checker warnings.

(5) Correctly indicate to the end-of-operation callback whether an
operation completed or was cancelled.

(6) Add a check for multiple cookie relinquishment.

(7) Fix a path through the asynchronous write that doesn't wake up a
waiter for a page if the cache decides not to write that page, but
discards it instead.

There a couple of patches to add tracepoints to fscache and cachefiles:

(8) Add tracepoints for cookie operators, object state machine execution,
cachefiles object management and cachefiles VFS operations.

(9) Add tracepoints for fscache operation management and page wrangling.

And then three development patches:

(10) Attach the index key and auxiliary data to the cookie, pass this
information through various fscache-netfs API functions and get rid of
the callbacks to the netfs to get it.

This means that the cache can get at this information, even if the
netfs goes away. It also means that the cache can be lazy in updating
the coherency data.

(11) Pass the object data size through various fscache-netfs API rather
than calling back to the netfs for it, and store the value in the
object.

This makes it easier to correctly resize the object, as the size is
updated on writes to the cache, rather than calling back out to the
netfs.

(12) Maintain a catalogue of allocated cookies. This makes it possible to
catch cookie collision up front rather than down in the bowels of the
cache being run from a service thread from the object state machine.

This will also make it possible in the future to reconnect to a cookie
that's not gone dead yet because it's waiting for finalisation of the
storage and also make it possible to bring cookies online if the cache
is added after the cookie has been obtained.


The patches are tagged here:

git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs.git
tags/fscache-next-20180404

and can also be found on this branch:

http://git.kernel.org/cgit/linux/kernel/git/dhowells/linux-fs.git/log/?h=fscache-next

David
---
David Howells (12):
afs: Invalidate cache on server data change
afs: Use the vnode ID uniquifier in the cache key not the aux data
afs: Be more aggressive in retiring cached vnodes
fscache, cachefiles: Fix checker warnings
fscache: Pass the correct cancelled indications to fscache_op_complete()
fscache: Detect multiple relinquishment of a cookie
fscache: Fix hanging wait on page discarded by writeback
fscache: Add tracepoints
fscache: Add more tracepoints
fscache: Attach the index key and aux data to the cookie
fscache: Pass object size in rather than calling back for it
fscache: Maintain a catalogue of allocated cookies


Documentation/filesystems/caching/netfs-api.txt | 157 +++----
fs/9p/cache.c | 100 +---
fs/afs/cache.c | 150 ------
fs/afs/cell.c | 6
fs/afs/file.c | 6
fs/afs/inode.c | 49 ++
fs/afs/internal.h | 7
fs/afs/volume.c | 6
fs/cachefiles/interface.c | 61 ++-
fs/cachefiles/internal.h | 2
fs/cachefiles/main.c | 1
fs/cachefiles/namei.c | 75 ++-
fs/cachefiles/rdwr.c | 1
fs/cachefiles/xattr.c | 8
fs/ceph/cache.c | 113 +----
fs/cifs/cache.c | 168 -------
fs/cifs/fscache.c | 130 +++++-
fs/cifs/fscache.h | 13 +
fs/fscache/cache.c | 2
fs/fscache/cookie.c | 386 ++++++++++++++---
fs/fscache/fsdef.c | 55 --
fs/fscache/internal.h | 43 ++
fs/fscache/main.c | 1
fs/fscache/netfs.c | 26 -
fs/fscache/object-list.c | 28 +
fs/fscache/object.c | 66 ++-
fs/fscache/operation.c | 26 +
fs/fscache/page.c | 84 +++-
fs/fscache/stats.c | 1
fs/nfs/fscache-index.c | 159 -------
fs/nfs/fscache.c | 89 +++-
fs/nfs/fscache.h | 15 +
include/linux/fscache-cache.h | 26 +
include/linux/fscache.h | 141 ++++--
include/trace/events/cachefiles.h | 325 ++++++++++++++
include/trace/events/fscache.h | 535 +++++++++++++++++++++++
36 files changed, 2012 insertions(+), 1049 deletions(-)
create mode 100644 include/trace/events/cachefiles.h
create mode 100644 include/trace/events/fscache.h