[PATCH v6 00/19] nfsd: open file caching

From: Jeff Layton <jlayton-vpEMnDpepFuMZCB2o+C8xQ@public.gmane.org>
To: bfields-uC3wQj2KruNg9hUCZPvPmw@public.gmane.org
Cc: linux-nfs-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	linux-fsdevel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	Al Viro <viro-3bDd1+5oDREiFSDQTTA3OLVCufUGDwFn@public.gmane.org>
Subject: [PATCH v6 00/19] nfsd: open file caching
Date: Tue, 20 Oct 2015 13:33:33 -0400	[thread overview]
Message-ID: <1445362432-18869-1-git-send-email-jeff.layton@primarydata.com> (raw)

v6:
- rename delayed_fput infrastructure to global_fput
- drop list_lru_rotate patch, rework LRU list code to use LRU_ROTATE
  and a new NFSD_FILE_REFERENCED flag
- rework fsnotify_mark handling to be done with separate allocation
- bugfixes

v5:
- switch to using flush_delayed_fput instead of __fput_sync
- hash on inode->i_ino instead of inode pointer
- add /proc/fs/nfsd/file_cache_stats file to track stats on the hash
- eliminate extra fh_verify in nfsd_file_acquire

v4:
- squash some of the patches down into one patch to reduce churn
- close cached open files after unlink instead of before
- don't just close files after nfsd does an unlink, must do it
  after any vfs-layer unlink. Use fsnotify to handle that.
- use a SRCU notifier chain for setlease
- add patch to allow non-kthreads to do a fput_sync

v3:
- open files are now hashed on inode pointer instead of fh
- eliminate the recurring workqueue job in favor of shrinker/LRU and
  notifier from lease setting code
- have nfsv4 use the cache as well
- removal of raparms cache

v2:
- changelog cleanups and clarifications
- allow COMMIT to use cached open files
- tracepoints for nfsd_file cache
- proactively close open files prior to REMOVE, or a RENAME over a
  positive dentry

This is the sixth posting of this patchset. For those just tuning in
now, the basic idea here is to allow nfsd to keep a cache of open
file descriptions, primarily to help NFSv3 workloads but also to clean
up some nastiness in the NFSv4 file handling.

Of course, we can't keep files open indefinitely, so much of the new
infrastructure is geared toward allowing the files to be closed on
demand, in the following cases:

- nfsd_files are released whenever the inode's link count goes to zero
- they are released when userspace wants to set a lease on the inode
- when a shrinker callback occurs for the nfsd_file cache
- when filesystems are unexported or nfsd is shut down, we clean
  out the cache

This allows nfsd to keep the file open basically indefinitely. The
tricky part is the setlease case. To handle that properly we have to
allow userland processes to queue the fputs involved to a workqueue.
This means allowing non-kthreads to queue fputs to the delayed_fput
infrastructure.

Al, can you look and weigh in? Do the delayed_fput/global_fput
changes look reasonable?

Jeff Layton (19):
  nfsd: move include of state.h from trace.c to trace.h
  fs: have flush_delayed_fput flush the workqueue job
  fs: add a kerneldoc header to fput
  fs: rename "delayed_fput" infrastructure to "fput_global"
  fs: add fput_global
  fsnotify: export several symbols
  locks: create a new notifier chain for lease attempts
  sunrpc: add a new cache_detail operation for when a cache is flushed
  nfsd: add a new struct file caching facility to nfsd
  nfsd: keep some rudimentary stats on nfsd_file cache
  nfsd: allow filecache open to skip fh_verify check
  nfsd: hook up nfsd_write to the new nfsd_file cache
  nfsd: hook up nfsd_read to the nfsd_file cache
  nfsd: hook nfsd_commit up to the nfsd_file cache
  nfsd: convert nfs4_file->fi_fds array to use nfsd_files
  nfsd: have nfsd_test_lock use the nfsd_file cache
  nfsd: convert fi_deleg_file and ls_file fields to nfsd_file
  nfsd: hook up nfs4_preprocess_stateid_op to the nfsd_file cache
  nfsd: rip out the raparms cache

 fs/file_table.c              |  94 ++++--
 fs/locks.c                   |  37 +++
 fs/nfsd/Kconfig              |   2 +
 fs/nfsd/Makefile             |   3 +-
 fs/nfsd/export.c             |  14 +
 fs/nfsd/filecache.c          | 712 +++++++++++++++++++++++++++++++++++++++++++
 fs/nfsd/filecache.h          |  44 +++
 fs/nfsd/nfs3proc.c           |   2 +-
 fs/nfsd/nfs4layouts.c        |  12 +-
 fs/nfsd/nfs4proc.c           |  32 +-
 fs/nfsd/nfs4state.c          | 174 +++++------
 fs/nfsd/nfs4xdr.c            |  16 +-
 fs/nfsd/nfsctl.c             |  10 +
 fs/nfsd/nfsproc.c            |   2 +-
 fs/nfsd/nfssvc.c             |  16 +-
 fs/nfsd/state.h              |  10 +-
 fs/nfsd/trace.c              |   2 -
 fs/nfsd/trace.h              | 137 +++++++++
 fs/nfsd/vfs.c                | 269 ++++------------
 fs/nfsd/vfs.h                |  11 +-
 fs/nfsd/xdr4.h               |  15 +-
 fs/notify/group.c            |   2 +
 fs/notify/inode_mark.c       |   1 +
 fs/notify/mark.c             |   4 +
 include/linux/file.h         |   3 +-
 include/linux/fs.h           |   1 +
 include/linux/sunrpc/cache.h |   1 +
 init/main.c                  |   2 +-
 net/sunrpc/cache.c           |   3 +
 29 files changed, 1249 insertions(+), 382 deletions(-)
 create mode 100644 fs/nfsd/filecache.c
 create mode 100644 fs/nfsd/filecache.h

-- 
2.4.3

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