|| ||Milosz Tanski <email@example.com> |
|| ||firstname.lastname@example.org |
|| ||[PATCH 0/3] ceph: persistent caching with fscache |
|| ||Wed, 7 Aug 2013 19:15:07 -0400|
|| ||email@example.com, firstname.lastname@example.org, email@example.com, firstname.lastname@example.org, email@example.com, firstname.lastname@example.org|
|| ||Article, Thread
This is a new and reworked patchset. I would greatly appreciate another review
Since my last patchset I rethought how implement fscache in Ceph. Originally, I
started taking queues largely from the NFS and CIFS code. The code in those
filesystems as implemented is racy and I ended up wit the same kind of problems.
This was exasperated by how Ceph handles cache caps.
Previously I would create the fscache cookie every time we gained a cache cap
and remove it when we lost it.
The current approach is to create the cache cookie the first time we reference
the inode by a file. After that we don't get rid of the cookie till we dispose
of the inode. I like this approach a lot more then creating and destroying
fscache cookies every time we gain/loose a cache cap. And it avoids the need
for locking everywhere in the read, write, invalidate page code. It's not race
prone and simple. Finally, I don't have to worry about delaying a bunch of
work till later due to having the cap being in the inode spinlock.
The only piece of serialization now if taking out the i_mutex when creating the
cookie to prevent multiple open() race.
The cache is invalidated every time we open the file for write, size changes.
Every time we gain a cache cap we schedule a cookie re-validation to a work
queue (with the exception of the first one, as fscache already invokes
validation). The cache is ignored till the re-validation work runs and changes
the re-validation sequence number (sometimes invalidating it if needed).
In order to use this you need need kenel 3.11 rc3 or greater. 3.11 contains a
big number of core fscache fixes. Otherwise you'll quickly run into oops on a
high concurrent workload.
The first two patches I included were not written by me but were written by
Hongyi Jia. He implemented the cookie re-validation scheme into fscache core.
Hongyi Jia (2):
new cachefiles interface to check cache consistency
new fscache interface to check cache consistency
Milosz Tanski (1):
ceph: use fscache as a local presisent cache
fs/cachefiles/interface.c | 19 +++
fs/cachefiles/internal.h | 1 +
fs/cachefiles/xattr.c | 39 ++++++
fs/ceph/Kconfig | 9 ++
fs/ceph/Makefile | 2 +
fs/ceph/addr.c | 70 +++++++---
fs/ceph/cache.c | 306 ++++++++++++++++++++++++++++++++++++++++++
fs/ceph/cache.h | 117 ++++++++++++++++
fs/ceph/caps.c | 19 ++-
fs/ceph/file.c | 17 +++
fs/ceph/inode.c | 69 +++++++++-
fs/ceph/super.c | 48 ++++++-
fs/ceph/super.h | 17 +++
fs/fscache/cookie.c | 22 +++
include/linux/fscache-cache.h | 4 +
include/linux/fscache.h | 17 +++
16 files changed, 748 insertions(+), 28 deletions(-)
create mode 100644 fs/ceph/cache.c
create mode 100644 fs/ceph/cache.h
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