Here are some patches to debug and fix FS-Cache problems.
(1) A debugging patch to add a predictable pattern generator with a filesystem
interface. Can be used to generate regular apparent changes on the NFS
server. This was very useful in breaking FS-Cache.
(2) A patch to correctly mark cached netfs pages.
(3) A debugging patch to validate page->mapping on a page for which retrieval
was requested.
(4) A patch to downgrade memory allocation levels in the cache to not try so
hard and to be more willing to abort with ENOMEM. It's a cache - it
doesn't matter if we can't store something.
(5) A debugging patch to check that there are no read operations outstanding
on a cookie when it is relinquished.
(6) A debugging patch to check that the object cookie pointer doesn't get
cleared whilst we're trying to read for it.
(7) A patch to make conditional some debugging prints.
(8) A patch to make cookie relinquishment log a warning and wait for any
outstanding reads.
(9) A patch to fix up operation state handling and accounting.
(10) A patch to provide proper invalidation facilities.
(11) A patch to make a vfs_truncate() for cachefiles's invalidation to call.
Question: CacheFiles uses truncation in a couple of places. It has been
using notify_change() rather than sys_truncate() or something similar.
This means it bypasses a bunch of checks and suchlike that it possibly
should be making (security, file locking, lease breaking, vfsmount write).
Should it be using vfs_truncate() as added by a preceding patch or should
it use notify_write() and assume that anyone poking around in the cache
files on disk gets everything they deserve?
(12) A patch to provide invalidation for cachefiles.
(13) A patch to make NFS use the invalidation call.
David
---
David Howells (13):
NFS: Use FS-Cache invalidation
CacheFiles: Implement invalidation
VFS: Make more complete truncate operation available to CacheFiles
FS-Cache: Provide proper invalidation
FS-Cache: Fix operation state management and accounting
FS-Cache: Make cookie relinquishment wait for outstanding reads
CacheFiles: Make some debugging statements conditional
FS-Cache: Check cookie is still correct in __fscache_read_or_alloc_pages()
FS-Cache: Check that there are no read ops when cookie relinquished
CacheFiles: Downgrade the requirements passed to the allocator
FS-Cache: Validate page mapping pointer value
CacheFiles: Fix the marking of cached pages
Noisefs: A predictable noise producing fs for testing things
Documentation/filesystems/caching/backend-api.txt | 38 ++
Documentation/filesystems/caching/netfs-api.txt | 46 ++-
Documentation/filesystems/caching/object.txt | 23 +
Documentation/filesystems/caching/operations.txt | 2
fs/Kconfig | 1
fs/Makefile | 1
fs/cachefiles/interface.c | 57 +++-
fs/cachefiles/internal.h | 2
fs/cachefiles/key.c | 2
fs/cachefiles/rdwr.c | 118 ++++---
fs/cachefiles/xattr.c | 2
fs/fscache/cookie.c | 78 +++++
fs/fscache/internal.h | 10 +
fs/fscache/object.c | 74 +++++
fs/fscache/operation.c | 135 ++++++---
fs/fscache/page.c | 188 ++++++++++--
fs/fscache/stats.c | 11 +
fs/nfs/fscache.h | 20 +
fs/nfs/inode.c | 20 +
fs/nfs/nfs4proc.c | 2
fs/noisefs/Kconfig | 20 +
fs/noisefs/Makefile | 7
fs/noisefs/file.c | 331 +++++++++++++++++++++
fs/noisefs/inode.c | 171 +++++++++++
fs/noisefs/internal.h | 59 ++++
fs/noisefs/super.c | 302 +++++++++++++++++++
fs/open.c | 50 ++-
include/linux/fs.h | 1
include/linux/fscache-cache.h | 53 +++
include/linux/fscache.h | 50 +++
mm/page-writeback.c | 1
31 files changed, 1696 insertions(+), 179 deletions(-)
create mode 100644 fs/noisefs/Kconfig
create mode 100644 fs/noisefs/Makefile
create mode 100644 fs/noisefs/file.c
create mode 100644 fs/noisefs/inode.c
create mode 100644 fs/noisefs/internal.h
create mode 100644 fs/noisefs/super.c
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