NFS4ERR_DELAY is a legal reply when we call DESTROY_SESSION. It
usually means that the server is busy handling an unfinished RPC
request. Just sleep for a second and then retry.
We also need to be able to handle the NFS4ERR_BACK_CHAN_BUSY return
value. If the NFS server has outstanding callbacks, we just want to
similarly sleep & retry.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Cc: stable@vger.kernel.org
If walking the list in nfs4[01]_walk_client_list fails, then the most
likely explanation is that the server dropped the clientid before we
actually managed to confirm it. As long as our nfs_client is the very
last one in the list to be tested, the caller can be assured that this
is the case when the final return value is NFS4ERR_STALE_CLIENTID.
Reported-by: Ben Greear <greearb@candelatech.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Cc: Chuck Lever <chuck.lever@oracle.com>
Cc: stable@vger.kernel.org [>=3.7]
Tested-by: Ben Greear <greearb@candelatech.com>
This list was designed to store struct nfs4_client in the client side.
But nfs4_client was obsolete and has been removed from the source code.
So remove the unused list.
Signed-off-by: Yanchuan Nian <ycnian@gmail.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Currently, when an RPCSEC_GSS context has expired or is non-existent
and the users (Kerberos) credentials have also expired or are non-existent,
the client receives the -EKEYEXPIRED error and tries to refresh the context
forever. If an application is performing I/O, or other work against the share,
the application hangs, and the user is not prompted to refresh/establish their
credentials. This can result in a denial of service for other users.
Users are expected to manage their Kerberos credential lifetimes to mitigate
this issue.
Move the -EKEYEXPIRED handling into the RPC layer. Try tk_cred_retry number
of times to refresh the gss_context, and then return -EACCES to the application.
Signed-off-by: Andy Adamson <andros@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Currently, we see a lot of bouncing for the value of highest_used_slotid
due to the fact that slots are getting freed, instead of getting instantly
transmitted to the next waiting task.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
It is more important to preserve the task priority behaviour, which ensures
that things like reclaim writes take precedence over background and kupdate
writes.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
If the server requests a lower target_highest_slotid, then ensure
that we ping it with at least one RPC call containing an
appropriate SEQUENCE op. This ensures that the server won't need to
send a recall callback in order to shrink the slot table.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
nfs4_wait_clnt_recover and nfs4_client_recover_expired_lease are both
generic state related functions. As such, they belong in nfs4state.c,
and not nfs4proc.c
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Coalesce nfs4_check_drain_bc_complete and nfs4_check_drain_fc_complete
into a single function that can be called when the slot table is known
to be empty, then change nfs4_callback_free_slot() and nfs4_free_slot()
to use it.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
RFC5661 requires us to make sure that the server knows we've updated
our slot table size by sending at least one SEQUENCE op containing the
new 'highest_slotid' value.
We can do so using the 'CHECK_LEASE' functionality of the state
manager.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
The state manager no longer needs any special machinery to stop the
session flow and resize the slot table. It is all done on the fly by
the SEQUENCE op code now.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Instead of an array of slots, use a singly linked list of slots that
can be dynamically appended to or shrunk.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Allow the server to control the size of the session slot table
by adjusting the value of sr_target_max_slots in the reply to the
SEQUENCE operation.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Dynamic slot allocation in NFSv4.1 depends on the client being able to
track the server's target value for the highest slotid in the
slot table. See the reference in Section 2.10.6.1 of RFC5661.
To avoid ordering problems in the case where 2 SEQUENCE replies contain
conflicting updates to this target value, we also introduce a generation
counter, to track whether or not an RPC containing a SEQUENCE operation
was launched before or after the last update.
Also rename the nfs4_slot_table target_max_slots field to
'target_highest_slotid' to avoid confusion with a slot
table size or number of slots.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Move the session pointer into the slot table, then have struct nfs4_slot
point to that slot table.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
We can't send a SEQUENCE op unless the session is OK, so it is pointless
to handle the CHECK_LEASE state before we've dealt with SESSION_RESET
and BIND_CONN_TO_SESSION.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Since the addition of NFSv4 server trunking detection the mount context
calls nfs4_proc_exchange_id then schedules the state manager, which also
calls nfs4_proc_exchange_id. Setting the NFS4CLNT_LEASE_CONFIRM bit
makes the state manager skip the unneeded EXCHANGE_ID and continue on
with session creation.
Reported-by: Jorge Mora <mora@netapp.com>
Signed-off-by: Weston Andros Adamson <dros@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
We should reclaim reboot state when the clientid is stale.
Signed-off-by: Andy Adamson <andros@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
"Server trunking" is a fancy named for a multi-homed NFS server.
Trunking might occur if a client sends NFS requests for a single
workload to multiple network interfaces on the same server. There
are some implications for NFSv4 state management that make it useful
for a client to know if a single NFSv4 server instance is
multi-homed. (Note this is only a consideration for NFSv4, not for
legacy versions of NFS, which are stateless).
If a client cares about server trunking, no NFSv4 operations can
proceed until that client determines who it is talking to. Thus
server IP trunking discovery must be done when the client first
encounters an unfamiliar server IP address.
The nfs_get_client() function walks the nfs_client_list and matches
on server IP address. The outcome of that walk tells us immediately
if we have an unfamiliar server IP address. It invokes
nfs_init_client() in this case. Thus, nfs4_init_client() is a good
spot to perform trunking discovery.
Discovery requires a client to establish a fresh client ID, so our
client will now send SETCLIENTID or EXCHANGE_ID as the first NFS
operation after a successful ping, rather than waiting for an
application to perform an operation that requires NFSv4 state.
The exact process for detecting trunking is different for NFSv4.0 and
NFSv4.1, so a minorversion-specific init_client callout method is
introduced.
CLID_INUSE recovery is important for the trunking discovery process.
CLID_INUSE is a sign the server recognizes the client's nfs_client_id4
id string, but the client is using the wrong principal this time for
the SETCLIENTID operation. The SETCLIENTID must be retried with a
series of different principals until one works, and then the rest of
trunking discovery can proceed.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
If the state manager thread is not actually able to fully recover from
some situation, it wakes up waiters, who kick off a new state manager
thread. Quite often the fresh invocation of the state manager is just
as successful.
This results in a livelock as the client dumps thousands of NFS
requests a second on the network in a vain attempt to recover. Not
very friendly.
To mitigate this situation, add a delay in the state manager after
an unhandled error, so that the client sends just a few requests
every second in this case.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
We want to be able to pass on the information that the page was not
dirtied under a lock. Instead of adding a flag parameter, do this
by passing a pointer to a 'struct nfs_lock_owner' that may be NULL.
Also reuse this structure in struct nfs_lock_context to carry the
fl_owner_t and pid_t.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
For NFSv4 minor version 0, currently the cl_id_uniquifier allows the
Linux client to generate a unique nfs_client_id4 string whenever a
server replies with NFS4ERR_CLID_INUSE.
This implementation seems to be based on a flawed reading of RFC
3530. NFS4ERR_CLID_INUSE actually means that the client has presented
this nfs_client_id4 string with a different principal at some time in
the past, and that lease is still in use on the server.
For a Linux client this might be rather difficult to achieve: the
authentication flavor is named right in the nfs_client_id4.id
string. If we change flavors, we change strings automatically.
So, practically speaking, NFS4ERR_CLID_INUSE means there is some other
client using our string. There is not much that can be done to
recover automatically. Let's make it a permanent error.
Remove the recovery logic in nfs4_proc_setclientid(), and remove the
cl_id_uniquifier field from the nfs_client data structure. And,
remove the authentication flavor from the nfs_client_id4 string.
Keeping the authentication flavor in the nfs_client_id4.id string
means that we could have a separate lease for each authentication
flavor used by mounts on the client. But we want just one lease for
all the mounts on this client.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Handling a slot recall situation should always takes precedence over
state recovery to allow the server to manage its resources.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Both nfs4_reset_session and nfs41_init_clientid need to clear all the
session related state flags on success.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
The results from a call to nfs4_proc_create_session() should always
be fed into nfs4_handle_reclaim_lease_error, so that we can
handle errors such as NFS4ERR_SEQ_MISORDERED correctly.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Let nfs4_schedule_session_recovery() handle the details of choosing
between resetting the session, and other session related recovery.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Ensure that we handle NFS4ERR_DELAY errors separately, and then
let nfs4_recovery_handle_error() handle all other cases.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
In order to avoid races with other RPC calls that end up setting the
NFS4CLNT_BIND_CONN_TO_SESSION flag.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Apparently the patch "NFS: Always use the same SETCLIENTID boot verifier"
is tickling a Linux nfs server bug, and causing a regression: the server
can get into a situation where it keeps replying NFS4ERR_SEQ_MISORDERED
to our CREATE_SESSION request even when we are sending the correct
sequence ID.
Fix this by purging the lease and then retrying.
Reported-by: Bryan Schumaker <bjschuma@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Try to consolidate the error handling for nfs4_reclaim_lease into
a single function instead of doing a bit here, and a bit there...
Also ensure that NFS4CLNT_PURGE_STATE handles errors correctly.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
The state manager can handle SEQ4_STATUS_CB_PATH_DOWN* flags with a
BIND_CONN_TO_SESSION instead of destroying the session and creating a new one.
Signed-off-by: Weston Andros Adamson <dros@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
nfs4_reset_all_state() refreshes the boot verifier a server sees to
trigger that server to wipe this client's state. This function is
invoked when an NFSv4.1 server reports that it has revoked some or
all of a client's NFSv4 state.
To facilitate server trunking discovery, we will eventually want to
move the cl_boot_time field to a more global structure. The Uniform
Client String model (and specifically, server trunking detection)
requires that all servers see the same boot verifier until the client
actually does reboot, and not a fresh verifier every time the client
unmounts and remounts the server.
Without the cl_boot_time field, however, nfs4_reset_all_state() will
have to find some other way to force the server to purge the client's
NFSv4 state.
Because these verifiers are opaque (ie, the server doesn't know or
care that they happen to be timestamps), we can force the server
to wipe NFSv4 state by updating the boot verifier as we do now, then
immediately afterwards establish a fresh client ID using the old boot
verifier again.
Hopefully there are no extra paranoid server implementations that keep
track of the client's boot verifiers and prevent clients from reusing
a previous one.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
