[RFC PATCH 0/6] vfs: Make icache searchable under RCU

From: David Howells
Date: Thu Apr 18 2019 - 10:06:04 EST

Hi Al

Here are some patches that make the icache searchable under RCU. This
benefits ext4 (which can use it to find an inode to update the timestamps on)
and afs (which can use it to find a vnode to invalidate the callback promise

It might also benefit NTFS, if its use ilookup5_nowait() can be substituted
for. I'm not sure whether it actually needs to wait for inodes that are
undergoing deletion.

The first patch in the series attempts to fix the non-use of locking in Coda
when it moves an inode between buckets because it needs to update the search

David Howells (6):
vfs, coda: Fix the lack of locking in FID replacement inode rehashing
vfs: Change inode_hash_lock to a seqlock
vfs: Allow searching of the icache under RCU conditions
afs: Use RCU inode cache search for callback resolution
ext4: Search for an inode to update under the RCU lock if we can
vfs: Delete find_inode_nowait()

fs/afs/callback.c | 12 ++
fs/coda/cnode.c | 11 ++
fs/ext4/inode.c | 41 ++++---
fs/inode.c | 309 ++++++++++++++++++++++++++++++++++++----------------
include/linux/fs.h | 11 +-
5 files changed, 260 insertions(+), 124 deletions(-)