If an RPC call is interrupted, assume that the server hasn't processed
the RPC call so that the next time we use the slot, we know that if we
get a NFS4ERR_SEQ_MISORDERED or NFS4ERR_SEQ_FALSE_RETRY, we just have
to bump the sequence number.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Shave a few bytes off the slot table size by moving the RPC timestamp
into the sequence results.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
If the server returns NFS4ERR_SEQ_MISORDERED, it could be a sign
that the slot was retired at some point. Retry the attempt after
reinitialising the slot sequence number to 1.
Also add a handler for NFS4ERR_SEQ_FALSE_RETRY. Just bump the slot
sequence number and retry...
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>
Most (all) NFS4ERR_BADSLOT errors are due to the client failing to
respect the server's sr_highest_slotid limit. This mainly happens
due to reordered RPC requests.
The way to handle it is simply to drop the slot that we're using,
and retry using the new highest_slotid limits.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Commit 1f1ea6c "NFSv4: Fix buffer overflow checking in
__nfs4_get_acl_uncached" accidently dropped the checking for too small
result buffer length.
If someone uses getxattr on "system.nfs4_acl" on an NFSv4 mount
supporting ACLs, the ACL has not been cached and the buffer suplied is
too short, we still copy the complete ACL, resulting in kernel and user
space memory corruption.
Signed-off-by: Sven Wegener <sven.wegener@stealer.net>
Cc: stable@kernel.org
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>
We want to preserve the rpc_task priority for things like writebacks,
that may have differing levels of urgency.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
All it does is pass its arguments through to another function. Let's
cut out the middleman...
Signed-off-by: Bryan Schumaker <bjschuma@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Privileged rpc calls are those that are run by the state recovery thread,
in cases where we're trying to recover the system after a server reboot
or a network partition. In those cases, we want to fence off all other
rpc calls (see nfs4_begin_drain_session()) so that they don't end up
using stateids or clientids that are in the process of being recovered.
Prior to this patch, we had to set up special callback functions in
order to declare an rpc call as being privileged.
By adding a new field to the sequence arguments, this patch simplifies
things considerably, and allows us to declare the rpc call as privileged
before it is run.
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>
We shouldn't need to pass the 'cache_reply' parameter if we
initialise the sequence_args/sequence_res in the caller.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Nobody calls nfs4_setup_sequence or nfs41_setup_sequence without
also calling rpc_call_start() on success. This commit therefore
folds the rpc_call_start call into nfs41_setup_sequence().
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
There is no point in using nfs4_setup_sequence or nfs4_sequence_done
in pure NFSv4.1 functions. We already know that those have sessions...
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>
If the NFSv4.1 session slot allocation fails due to an ENOMEM condition,
then set the task->tk_timeout to 1/4 second to ensure that we do retry
the slot allocation more quickly.
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>
Ensure that the NFSv4.1 CB_RECALL_SLOT callback updates the slot table
target max slotid safely.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
When the server tells us that it is dynamically resizing the session
replay cache, we should reset the sequence number for those slots
that have been deallocated.
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>
Change the argument to take the pointer to the slot, instead of
just the slotid.
We know that the new value of highest_used_slot must be less than
the current value. No need to scan the whole table.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Clean up the NFSv4.1 slot allocation by replacing nfs_find_slot() with
a function nfs_alloc_slot() that returns a pointer to the nfs4_slot
instead of an offset into the slot table.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Instead of doing slot table pointer gymnastics every time we want to
know which slot we're using.
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 must always bump the clientid sequence number after a successful
call to CREATE_SESSION on the server. The result of
nfs4_verify_channel_attrs() is irrelevant to that requirement.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
If we're mounting a new filesystem, ensure that the session has negotiated
large enough request and reply sizes to match the wsize and rsize mount
arguments.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Don't store the target request and response sizes in the same
variables used to store the server's replies to those targets.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
If I mount an NFS v4.1 server to a single client multiple times and then
run xfstests over each mountpoint I usually get the client into a state
where recovery deadlocks. The server informs the client of a
cb_path_down sequence error, the client then does a
bind_connection_to_session and checks the status of the lease.
I found that bind_connection_to_session sets the NFS4_SESSION_DRAINING
flag on the client, but this flag is never unset before
nfs4_check_lease() reaches nfs4_proc_sequence(). This causes the client
to deadlock, halting all NFS activity to the server. nfs4_proc_sequence()
is only called by the state manager, so I can change it to run in privileged
mode to bypass the NFS4_SESSION_DRAINING check and avoid the deadlock.
Signed-off-by: Bryan Schumaker <bjschuma@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Cc: stable@vger.kernel.org
Return errno - not an NFS4ERR_. This worked because NFS4ERR_ACCESS == EACCES.
Signed-off-by: Weston Andros Adamson <dros@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Use nfs_sb_deactive_async instead of nfs_sb_deactive when in a workqueue
context. This avoids a deadlock where rpc_shutdown_client loops forever
in a workqueue kworker context, trying to kill all RPC tasks associated with
the client, while one or more of these tasks have already been assigned to the
same kworker (and will never run rpc_exit_task).
This approach is needed because RPC tasks that have already been assigned
to a kworker by queue_work cannot be canceled, as explained in the comment
for workqueue.c:insert_wq_barrier.
Signed-off-by: Weston Andros Adamson <dros@netapp.com>
[Trond: add module_get/put.]
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
If the state recovery machinery is triggered by the call to
nfs4_async_handle_error() then we can deadlock.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Cc: stable@vger.kernel.org
If we do not release the sequence id in cases where we fail to get a
session slot, then we can deadlock if we hit a recovery scenario.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Cc: stable@vger.kernel.org
Currently, we will schedule session recovery and then return to the
caller of nfs4_handle_exception. This works for most cases, but causes
a hang on the following test case:
Client Server
------ ------
Open file over NFS v4.1
Write to file
Expire client
Try to lock file
The server will return NFS4ERR_BADSESSION, prompting the client to
schedule recovery. However, the client will continue placing lock
attempts and the open recovery never seems to be scheduled. The
simplest solution is to wait for session recovery to run before retrying
the lock.
Signed-off-by: Bryan Schumaker <bjschuma@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Cc: stable@vger.kernel.org
nfs4_open_recover_helper zeros the nfs4_opendata result structures, removing
the result access_request information which leads to an XDR decode error.
Move the setting of the result access_request field to nfs4_init_opendata_res
which sets all the other required nfs4_opendata result fields and is shared
between the open and recover open paths.
Signed-off-by: Andy Adamson <andros@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
We currently make no distinction in attribute requests between normal OPENs
and OPEN with CLAIM_PREVIOUS. This offers more possibility of failures in
the GETATTR response which foils OPEN reclaim attempts.
Reduce the requested attributes to the bare minimum needed to update the
reclaim open stateid and split nfs4_opendata_to_nfs4_state processing
accordingly.
Signed-off-by: Andy Adamson <andros@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Trond Myklebust