[PATCH v2 00/10] server-side support for "inter" SSC copy

Olga Kornievskaia
2018-11-30T20:03:52Z

This patch series adds support for NFSv4.2 copy offload feature
allowing copy between two different NFS servers.

This functionality depends on the VFS ability to support generic
copy_file_range() where a copy is done between an NFS file and
a local file system.

This feature is enabled by the kernel module parameter --
inter_copy_offload_enable -- and by default is disabled. There is
also a kernel compile configuration of NFSD_V4_2_INTER_SSC that
adds dependency on the NFS client side functions called from the
server.

These patches work on top of existing async intra copy offload
patches. For the "inter" SSC, the implementation only supports
asynchronous inter copy.

On the source server, upon receiving a COPY_NOTIFY, it generate a
unique stateid that's kept in the global list. Upon receiving a READ
with a stateid, the code checks the normal list of open stateid and
now additionally, it'll check the copy state list as well before
deciding to either fail with BAD_STATEID or find one that matches.
The stored stateid is only valid to be used for the first time
with a choosen lease period (90s currently). When the source server
received an OFFLOAD_CANCEL, it will remove the stateid from the
global list. Otherwise, the copy stateid is removed upon the removal
of its "parent" stateid (open/lock/delegation stateid).

On the destination server, upon receiving a COPY request, the server
establishes the necessary clientid/session with the source server.
It calls into the NFS client code to establish the necessary
open stateid, filehandle, file description (without doing an NFS open).
Then the server calls into the copy_file_range() to preform the copy
where the source file will issue NFS READs and then do local file
system writes (this depends on the VFS ability to do cross device
copy_file_range().

v2:
-- in on top of 4.20-rc4 + client side inter patch series
-- VFS changes to do enable generic copy_file_range() and then NFS
falls back on generic_copy_file_range() for previous EXDEV/OPNOTSUPP
errors
-- hopefully addressed Bruce's review comments (highlights are):
--- copy_notify patch: addressed naming, sc_cp_list access is
now protected by s2s_cp_lock
--- fillin netloc4 patch: address the size and added WARN_ON
--- add ca_source to COPY: decode only 1 address, dont allocate
memory (the rest into dummy)
--- check stateid against stored: moved the refcount under lock
--- allow stale filehandle: adding a loop to go thru the ops in
the compound, store/manage puttfh if copy is present in the compound
mark the source putfh as "no verify".

All the patches (client inter) and this patch series is available
from git://linux-nfs.org/projects/aglo/linux.git under the "linux-ssc"
branch

Olga Kornievskaia (10):
VFS generic copy_file_range() support
NFS fallback to generic_copy_file_range
NFSD fill-in netloc4 structure
NFSD add ca_source_server<> to COPY
NFSD return nfs4_stid in nfs4_preprocess_stateid_op
NFSD add COPY_NOTIFY operation
NFSD check stateids against copy stateids
NFSD generalize nfsd4_compound_state flag names
NFSD: allow inter server COPY to have a STALE source server fh
NFSD add nfs4 inter ssc to nfsd4_copy

fs/nfs/nfs4file.c | 9 +-
fs/nfsd/Kconfig | 10 ++
fs/nfsd/nfs4proc.c | 406 ++++++++++++++++++++++++++++++++++++++++++++++-----
fs/nfsd/nfs4state.c | 124 ++++++++++++++--
fs/nfsd/nfs4xdr.c | 166 ++++++++++++++++++++-
fs/nfsd/nfsd.h | 32 ++++
fs/nfsd/nfsfh.h | 5 +-
fs/nfsd/nfssvc.c | 6 +
fs/nfsd/state.h | 21 ++-
fs/nfsd/xdr4.h | 37 ++++-
fs/read_write.c | 66 +++++++--
include/linux/fs.h | 7 +
include/linux/nfs4.h | 1 +
mm/filemap.c | 6 +-
14 files changed, 810 insertions(+), 86 deletions(-)

--
1.8.3.1