This patchset aims to make soft mounts a viable option for NFSv4 clients
by minimising the risk of false positive timeouts, while allowing for
faster failover of reads and writes once a timeout is actually observed.
The patches rely on the NFS server correctly implementing the contract
specified in RFC7530 section 3.1.1 with respect to not dropping requests
while the transport connection is up. When this is the case, the client
can safely assume that if the request has not received a reply after
transmitting a RPC request, it is not because the request was dropped,
but rather is due to congestion, or slow processing on the server.
IOW: as long as the connection remains up, there is no need for requests
to time out.
The patches break down roughly as follows:
- A set of patches to clean up the RPC engine timeouts, and ensure they
are accurate.
- A set of patches to change the 'soft' mount semantics for NFSv4.x.
- A set of patches to add a new 'softerr' mount option that works like
soft, but explicitly signals timeouts using the ETIMEDOUT error code
rather than using EIO. This allows applications to tune their
behaviour (e.g. by failing over to a different server) if a timeout
occurs.
- A set of patches to change the NFS error reporting so that it matches
that of local filesystems w.r.t. guarantees that filesystem errors are
seen once and once only.
- A patch to ensure the safe interruption of NFS4ERR_DELAYed operations
- A patch to ensure that pNFS operations can be forced to break out
of layout error cycles after a certain number of retries.
- A few cleanups...
-------
Changes since v1:
- Change NFSv4 soft timeout condition to prevent all requests from
timing out when the connection is still up, instead of just the
ones that have been sent.
- RPC queue timer cleanups
- Ratelimit the "server not responding" messages
Changes since v2:
- Fix potential NULL dereference issues pointed out by Dan Carpenter
- Ensure lock contexts keeps a reference to the open context
Trond Myklebust (29):
SUNRPC: Fix up task signalling
SUNRPC: Refactor rpc_restart_call/rpc_restart_call_prepare
SUNRPC: Refactor xprt_request_wait_receive()
SUNRPC: Refactor rpc_sleep_on()
SUNRPC: Remove unused argument 'action' from rpc_sleep_on_priority()
SUNRPC: Add function rpc_sleep_on_timeout()
SUNRPC: Fix up tracking of timeouts
SUNRPC: Simplify queue timeouts using timer_reduce()
SUNRPC: Declare RPC timers as TIMER_DEFERRABLE
SUNRPC: Ensure that the transport layer respect major timeouts
SUNRPC: Add tracking of RPC level errors
SUNRPC: Make "no retrans timeout" soft tasks behave like softconn for
timeouts
SUNRPC: Start the first major timeout calculation at task creation
SUNRPC: Ensure to ratelimit the "server not responding" syslog
messages
SUNRPC: Add the 'softerr' rpc_client flag
NFS: Consider ETIMEDOUT to be a fatal error
NFS: Move internal constants out of uapi/linux/nfs_mount.h
NFS: Add a mount option "softerr" to allow clients to see ETIMEDOUT
errors
NFS: Don't interrupt file writeout due to fatal errors
NFS: Don't call generic_error_remove_page() while holding locks
NFS: Don't inadvertently clear writeback errors
NFS: Replace custom error reporting mechanism with generic one
NFS: Fix up NFS I/O subrequest creation
NFS: Remove unused argument from nfs_create_request()
pNFS: Add tracking to limit the number of pNFS retries
NFS: Allow signal interruption of NFS4ERR_DELAYed operations
NFS: Ensure that all nfs lock contexts have a valid open context
NFS: Add a helper to return a pointer to the open context of a struct
nfs_page
NFS: Remove redundant open context from nfs_page
fs/lockd/clntproc.c | 4 +-
fs/nfs/client.c | 2 +
fs/nfs/direct.c | 11 +-
fs/nfs/file.c | 31 +---
fs/nfs/filelayout/filelayout.c | 4 +-
fs/nfs/flexfilelayout/flexfilelayout.c | 14 +-
fs/nfs/inode.c | 13 +-
fs/nfs/internal.h | 7 +-
fs/nfs/nfs4_fs.h | 1 +
fs/nfs/nfs4file.c | 2 +-
fs/nfs/nfs4proc.c | 159 +++++++++++++++------
fs/nfs/pagelist.c | 123 +++++++++-------
fs/nfs/pnfs.c | 4 +-
fs/nfs/pnfs.h | 4 +-
fs/nfs/read.c | 6 +-
fs/nfs/super.c | 15 +-
fs/nfs/write.c | 70 +++++----
fs/nfsd/nfs4callback.c | 4 +-
include/linux/nfs_fs.h | 1 -
include/linux/nfs_fs_sb.h | 10 ++
include/linux/nfs_page.h | 12 +-
include/linux/sunrpc/clnt.h | 2 +
include/linux/sunrpc/sched.h | 20 ++-
include/linux/sunrpc/xprt.h | 6 +-
include/trace/events/sunrpc.h | 8 +-
include/uapi/linux/nfs_mount.h | 9 --
net/sunrpc/auth_gss/auth_gss.c | 5 +-
net/sunrpc/clnt.c | 116 +++++++++------
net/sunrpc/debugfs.c | 2 +-
net/sunrpc/rpcb_clnt.c | 3 +-
net/sunrpc/sched.c | 158 +++++++++++++++-----
net/sunrpc/xprt.c | 150 ++++++++++++-------
net/sunrpc/xprtrdma/svc_rdma_backchannel.c | 2 +-
net/sunrpc/xprtrdma/transport.c | 2 +-
net/sunrpc/xprtsock.c | 9 +-
35 files changed, 643 insertions(+), 346 deletions(-)
--
2.20.1
