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>
Don't put an ACCESS op in OPEN compound if O_EXCL, because ACCESS
will return permission denied for all bits until close.
Fixes a regression due to commit 6168f62c (NFSv4: Add ACCESS operation to
OPEN compound)
Signed-off-by: Weston Andros Adamson <dros@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Don't check MAY_WRITE as a newly created file may not have write mode bits,
but POSIX allows the creating process to write regardless.
This is ok because NFSv4 OPEN ops handle write permissions correctly -
the ACCESS in the OPEN compound is to differentiate READ v EXEC permissions.
Fixes a regression due to commit 6168f62c (NFSv4: Add ACCESS operation to
OPEN compound)
Signed-off-by: Weston Andros Adamson <dros@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
If the layoutget call returns a stateid error, we want to invalidate the
layout stateid, and/or recover the open stateid.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
After commit e38eb650 (NFS: set_pnfs_layoutdriver() from
nfs4_proc_fsinfo()), set_pnfs_layoutdriver() is called inside
nfs4_proc_fsinfo(), but pnfs_blksize is not set. It causes setting
blocklayoutdriver failure and pnfsblock mount failure.
Cc: stable <stable@vger.kernel.org> [since v3.5]
Signed-off-by: Peng Tao <tao.peng@emc.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
An optional boot parameter is introduced to allow client
administrators to specify a string that the Linux NFS client can
insert into its nfs_client_id4 id string, to make it both more
globally unique, and to ensure that it doesn't change even if the
client's nodename changes.
If this boot parameter is not specified, the client's nodename is
used, as before.
Client installation procedures can create a unique string (typically,
a UUID) which remains unchanged during the lifetime of that client
instance. This works just like creating a UUID for the label of the
system's root and boot volumes.
Signed-off-by: Chuck Lever <chuck.lever@oracle.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>
Currently, when identifying itself to NFS servers, the Linux NFS
client uses a unique nfs_client_id4.id string for each server IP
address it talks with. For example, when client A talks to server X,
the client identifies itself using a string like "AX". The
requirements for these strings are specified in detail by RFC 3530
(and bis).
This form of client identification presents a problem for Transparent
State Migration. When client A's state on server X is migrated to
server Y, it continues to be associated with string "AX." But,
according to the rules of client string construction above, client
A will present string "AY" when communicating with server Y.
Server Y thus has no way to know that client A should be associated
with the state migrated from server X. "AX" is all but abandoned,
interfering with establishing fresh state for client A on server Y.
To support transparent state migration, then, NFSv4.0 clients must
instead use the same nfs_client_id4.id string to identify themselves
to every NFS server; something like "A".
Now a client identifies itself as "A" to server X. When a file
system on server X transitions to server Y, and client A identifies
itself as "A" to server Y, Y will know immediately that the state
associated with "A," whether it is native or migrated, is owned by
the client, and can merge both into a single lease.
As a pre-requisite to adding support for NFSv4 migration to the Linux
NFS client, this patch changes the way Linux identifies itself to NFS
servers via the SETCLIENTID (NFSv4 minor version 0) and EXCHANGE_ID
(NFSv4 minor version 1) operations.
In addition to removing the server's IP address from nfs_client_id4,
the Linux NFS client will also no longer use its own source IP address
as part of the nfs_client_id4 string. On multi-homed clients, the
value of this address depends on the address family and network
routing used to contact the server, thus it can be different for each
server.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
The OPEN operation has no way to differentiate an open for read and an
open for execution - both look like read to the server. This allowed
users to read files that didn't have READ access but did have EXEC access,
which is obviously wrong.
This patch adds an ACCESS call to the OPEN compound to handle the
difference between OPENs for reading and execution. Since we're going
through the trouble of calling ACCESS, we check all possible access bits
and cache the results hopefully avoiding an ACCESS call in the future.
Signed-off-by: Weston Andros Adamson <dros@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
I put the client into an open recovery loop by:
Client: Open file
read half
Server: Expire client (echo 0 > /sys/kernel/debug/nfsd/forget_clients)
Client: Drop vm cache (echo 3 > /proc/sys/vm/drop_caches)
finish reading file
This causes a loop because the client never updates the nfs4_state after
discovering that the delegation is invalid. This means it will keep
trying to read using the bad delegation rather than attempting to re-open
the file.
Signed-off-by: Bryan Schumaker <bjschuma@netapp.com>
CC: stable@vger.kernel.org [3.4+]
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
If we are reading through a delegation, and the delegation is OK then
state->stateid will still point to a delegation stateid and not an open
stateid.
Signed-off-by: Bryan Schumaker <bjschuma@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
