Commit Graph

169155 Commits

Author SHA1 Message Date
Ricardo Labiaga 9dfdf404c9 nfs41: Don't clear DRAINING flag on NFS4ERR_STALE_CLIENTID
If CREATE_SESSION fails with NFS4ERR_STALE_CLIENTID, don't clear the
NFS4CLNT_SESSION_DRAINING flag and don't wake RPCs waiting for the
session to be reestablished.  We don't have a session yet, so there
is no reason to wake other RPCs.

This avoids sending spurious compounds with bogus sequenceID during
session and state recovery.

Signed-off-by: Ricardo Labiaga <Ricardo.Labiaga@netapp.com>
[Trond.Myklebust@netapp.com: cleaned up patch by adding the
                             nfs41_begin/end_drain_session() helpers]
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2009-12-06 12:57:34 -05:00
Ricardo Labiaga 9430fb6b53 nfs41: nfs41_setup_state_renewal
Move call to get the lease time and the setup of the state
renewal out of nfs4_create_session so that it can be called
after clearing the DRAINING flag.  We use the getattr RPC
to obtain the lease time, which requires a sequence slot.

Signed-off-by: Ricardo Labiaga <Ricardo.Labiaga@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2009-12-06 12:23:46 -05:00
Trond Myklebust bcb56164ce NFSv41: More cleanups
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2009-12-05 19:32:19 -05:00
Trond Myklebust 35dc1d74a8 NFSv41: Fix up some bugs in the NFS4CLNT_SESSION_DRAINING code
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2009-12-05 19:32:19 -05:00
Trond Myklebust d61e612a72 NFSv41: Clean up slot table management
We no longer need to maintain a distinction between nfs41_sequence_done and
nfs41_sequence_free_slot.

This fixes a number of slot table leakages in the NFSv4.1 code.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2009-12-05 19:32:19 -05:00
Trond Myklebust f26468fb93 NFSv41: Fix nfs4_proc_create_session
We should not assume that nfs41_init_clientid() will always want to
initialise the session. If it is being called due to a server reboot, then
we just want to reset the session after re-establishing the clientid.

Fix this by getting rid of the 'reset' parameter in
nfs4_proc_create_session(), and instead relying on whether or not the
session slot table pointer is non-NULL.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2009-12-05 19:32:11 -05:00
Ricardo Labiaga da6ebfe34a nfs41: Invoke RECLAIM_COMPLETE
This patch invokes RECLAIM_COMPLETE after the client is done
reclaiming state.

There are interpretations of the spec that suggest that
RECLAIM_COMPLETE should also be issued after a new clientid
has been obtained from the server and even if there is no
state to reclaim.  This tells the server that the client
has no state to reclaim even if the client isn't aware the
server may have rebooted.

Signed-off-by: Ricardo Labiaga <Ricardo.Labiaga@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2009-12-05 16:08:41 -05:00
Ricardo Labiaga fce5c838e1 nfs41: RECLAIM_COMPLETE functionality
Implements RECLAIM_COMPLETE as an asynchronous RPC.
NFS4ERR_DELAY is retried, NFS4ERR_DEADSESSION invokes the error handling
but does not result in a retry, since we don't want to have a lingering
RECLAIM_COMPLETE call sent in the middle of a possible new state recovery
cycle.  If a session reset occurs, a new wave of reclaim operations will
follow, containing their own RECLAIM_COMPLETE call.  We don't want a
retry to get on the way of recovery by incorrectly indicating to the
server that we're done reclaiming state.

A subsequent patch invokes the functionality.

Signed-off-by: Ricardo Labiaga <Ricardo.Labiaga@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2009-12-05 16:08:41 -05:00
Ricardo Labiaga 180197536b nfs41: RECLAIM_COMPLETE XDR functionality
XDR encoding and decoding for RECLAIM_COMPLETE.  Implements the necessary
encoding to indicate reclaim complete for the entire client.  In the future,
it can be extended to provide reclaim complete functionality for a single
file system after migration.

Signed-off-by: Ricardo Labiaga <Ricardo.Labiaga@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2009-12-05 16:08:40 -05:00
Ricardo Labiaga 8b173218bd Cleanup some NFSv4 XDR decode comments
Signed-off-by: Ricardo Labiaga <Ricardo.Labiaga@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2009-12-05 16:08:39 -05:00
Trond Myklebust 0556d1a695 NFSv41: nfs4_reset_session must always set NFS4CLNT_SESSION_DRAINING
Otherwise we have no guarantees that other processes won't start another
RPC call while we're resetting the session.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2009-12-05 15:03:20 -05:00
Alexandros Batsakis 2597641dea nfs41: v2 fix cb_recall bug
in NFSv4.1 the seqid part of a stateid in CB_RECALL must be 0

Signed-off-by: Alexandros Batsakis <batsakis@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2009-12-05 13:48:55 -05:00
Alexandros Batsakis 0629e370dd nfs41: check SEQUENCE status flag
the server can indicate a number of error conditions by setting the
appropriate bits in the SEQUENCE operation. The client re-establishes
state with the server when it receives one of those, with the action
depending on the specific case.

Signed-off-by: Alexandros Batsakis <batsakis@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2009-12-05 13:46:14 -05:00
Alexandros Batsakis 2449ea2e19 nfs41: V2 adjust max_rqst_sz, max_resp_sz w.r.t to rsize, wsize
The v4.1 client should take into account the desired rsize, wsize when
negotiating the max size in CREATE_SESSION. Accordingly, it should use
rsize, wsize that are smaller than the session negotiated values.

Signed-off-by: Alexandros Batsakis <batsakis@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2009-12-05 13:36:55 -05:00
Alexandros Batsakis 7b183d0d43 nfs41: remove server-only EXCHGID4_FLAG_CONFIRMED_R flag from exchange_id
Signed-off-by: Alexandros Batsakis <batsakis@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2009-12-05 13:33:25 -05:00
Alexandros Batsakis 4882ef72cd nfs41: add support for the exclusive create flags
In v4.1 the client MUST/SHOULD use the EXCLUSIVE4_1 flag instead of
EXCLUSIVE4, and GUARDED when the server supports persistent sessions.
For now (and until we support suppattr_exclcreat), we don't send any
attributes with EXCLUSIVE4_1 relying in the subsequent SETATTR as in v4.0

Signed-off-by: Alexandros Batsakis <batsakis@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2009-12-05 13:30:21 -05:00
Alexandros Batsakis d8cb1a7ce3 nfs41: check if session exists and if it is persistent
Signed-off-by: Alexandros Batsakis <batsakis@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2009-12-05 13:29:53 -05:00
Alexandros Batsakis 31f0960778 nfs41: V2 initial support for CB_RECALL_ANY
For now the clients returns _all_ the delegations of the specificed type
it holds

Signed-off-by: Alexandros Batsakis <batsakis@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2009-12-05 13:27:02 -05:00
Alexandros Batsakis c79571a508 nfs4: V2 return/expire delegations depending on their type
Signed-off-by: Alexandros Batsakis <batsakis@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2009-12-05 13:20:52 -05:00
Alexandros Batsakis b4a6f4966e nfs4: minor delegation cleaning
Signed-off-by: Alexandros Batsakis <batsakis@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2009-12-05 13:19:11 -05:00
Alexandros Batsakis 07bccc2dd4 nfs41: add support for callback with RPC version number 4
The NFSv4.1 spec-29 (18.36.3) says that the server MUST use an ONC RPC
(program) version number equal to 4 in callbacks sent to the client.
For now we allow both versions 1 and 4.

Signed-off-by: Alexandros Batsakis <batsakis@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2009-12-05 13:19:01 -05:00
Andy Adamson 0b9e2d41f1 nfs41: only state manager sets NFS4CLNT_SESSION_SETUP
Replace sync and async handlers setting of the NFS4CLNT_SESSION_SETUP bit with
setting NFS4CLNT_CHECK_LEASE, and let the state manager decide to reset the session.

Signed-off-by: Andy Adamson <andros@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2009-12-04 16:02:14 -05:00
Andy Adamson 691daf3b0c nfs41: drain session cleanup
Do not wake up the next slot_tbl_waitq task in nfs4_free_slot because we
may be draining the slot. Either signal the state manager that the session
is drained (the state manager wakes up tasks) OR wake up the next task.

In nfs41_sequence_done, the slot dereference is only needed in the sequence
operation success case.

Signed-off-by: Andy Adamson <andros@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2009-12-04 15:55:39 -05:00
Andy Adamson ea028ac925 nfs41: nfs41: fix state manager deadlock in session reset
If the session is reset during state recovery, the state manager thread can
sleep on the slot_tbl_waitq causing a deadlock.

Add a completion framework to the session.  Have the state manager thread set
a new session state (NFS4CLNT_SESSION_DRAINING) and wait for the session slot
table to drain.

Signal the state manager thread in nfs41_sequence_free_slot when the
NFS4CLNT_SESSION_DRAINING bit is set and the session is drained.

Reported-by: Trond Myklebust <trond@netapp.com>
Signed-off-by: Andy Adamson <andros@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2009-12-04 15:55:38 -05:00
Andy Adamson 05f0d23647 nfs41: remove nfs4_recover_session
nfs4_recover_session can put rpciod to sleep. Just use nfs4_schedule_recovery.

Reported-by: Trond Myklebust <trond.myklebust@netapp.com>
Signed-off-by: Andy Adamson <andros@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2009-12-04 15:55:37 -05:00
Andy Adamson 2628eddff1 nfs41: don't clear tk_action on success
Signed-off-by: Andy Adamson <andros@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2009-12-04 15:55:35 -05:00
Andy Adamson 8ba9bf8e51 nfs41: fix switch in nfs4_recovery_handle_error
Do not fall through and set NFS4CLNT_SESSION_RESET bit on NFS4ERR_EXPIRED

Signed-off-by: Andy Adamson <andros@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2009-12-04 15:55:34 -05:00
Andy Adamson b9179237e2 nfs41: fix switch in nfs4_handle_exception
Do not fall through and call nfs4_delay on session error handling.

Signed-off-by: Andy Adamson <andros@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2009-12-04 15:55:32 -05:00
Andy Adamson 36bbe34239 nfs41: free the slot on unhandled read errors
nfs4_read_done returns zero on unhandled errors. nfs_readpage_result will
return on a negative tk_status without freeing the slot.
Call nfs4_sequence_free_slot on unhandled errors in nfs4_read_done.

Signed-off-by: Andy Adamson <andros@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2009-12-04 15:55:30 -05:00
Andy Adamson e608e79f1b nfs41: call free slot from nfs4_restart_rpc
nfs41_sequence_free_slot can be called multiple times on SEQUENCE operation
errors.
No reason to inline nfs4_restart_rpc

Reported-by: Trond Myklebust <trond.myklebust@netapp.com>

nfs_writeback_done and nfs_readpage_retry call nfs4_restart_rpc outside the
error handler, and the slot is not freed prior to restarting in the rpc_prepare
state during session reset.

Fix this by moving the call to nfs41_sequence_free_slot from the error
path of nfs41_sequence_done into nfs4_restart_rpc, and by removing the test
for NFS4CLNT_SESSION_SETUP.
Always free slot and goto the rpc prepare state on async errors.

Signed-off-by: Andy Adamson <andros@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2009-12-04 15:55:29 -05:00
Andy Adamson 1d9ddde94a nfs41: nfs4_get_lease_time will never session reset
Make this clear by calling rpc_restart-call.
Prepare for nfs4_restart_rpc() to free slots.

Signed-off-by: Andy Adamson <andros@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2009-12-04 15:55:27 -05:00
Andy Adamson 6df08189ff nfs41: rename cl_state session SETUP bit to RESET
The bit is no longer used for session setup, only for session reset.

Signed-off-by: Andy Adamson <andros@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2009-12-04 15:55:05 -05:00
Andy Adamson 4d643d1dfa nfs41: add create session into establish_clid
Reported-by: Trond Myklebust <trond.myklebust@netapp.com>

Resetting the clientid from the state manager could result in not confirming
the clientid due to create session not being called.

Move the create session call from the NFS4CLNT_SESSION_SETUP state manager
initialize session case into the NFS4CLNT_LEASE_EXPIRED case establish_clid
call.

Signed-off-by: Andy Adamson <andros@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2009-12-04 15:52:24 -05:00
Trond Myklebust 7285f2d2ff Merge branch 'devel' into linux-next 2009-12-03 21:27:36 -05:00
NeilBrown 44ed3556ba NFS4ERR_FILE_OPEN handling in Linux/NFS
NFS4ERR_FILE_OPEN is return by the server when an operation cannot be
performed because the file is currently open and local (to the server)
semantics prohibit the operation while the file is open.
A typical case is a RENAME operation on an MS-Windows platform, which
prevents rename while the file is open.

While it is possible that such a condition is transitory, it is also
very possible that the file will be held open for an extended period
of time thus preventing the operation.

The current behaviour of Linux/NFS is to retry the operation
indefinitely.  This is not appropriate - we do not expect a rename to
take an arbitrary amount of time to complete.

Rather, and error should be returned.  The most obvious error code
would be EBUSY, which is a legal at least for 'rename' and 'unlink',
and accurately captures the reason for the error.

This patch allows a few retries until about 2 seconds have elapsed,
then returns EBUSY.

Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2009-12-03 21:26:36 -05:00
Trond Myklebust 0b08b07507 Merge branch 'bugfixes' into nfs-for-next 2009-12-03 16:01:51 -05:00
Miklos Szeredi 24e93025ee nfs: clean up sillyrenaming in nfs_rename()
The d_instantiate(new_dentry, NULL) is superfluous, the dentry is
already negative.  Rehashing this dummy dentry isn't needed either,
d_move() works fine on an unhashed target.

The re-checking for busy after a failed nfs_sillyrename() is bogus
too: new_dentry->d_count < 2 would be a bug here.

Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2009-12-03 15:58:56 -05:00
Miklos Szeredi 27226104e6 nfs: dont unhash target if renaming a directory
Move unhashing the target to after the check for existence and being a
non-directory.

If renaming a directory then the VFS already unhashes the target if it
is not busy.  If it's busy then acquiring more references during the
rename makes no difference.

Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2009-12-03 15:58:56 -05:00
Miklos Szeredi 28f79a1a69 nfs: fix comments in nfs_rename()
Comments are wrong or out of date.  In particular d_drop() doesn't
free the inode it just unhashes the dentry.  And if target is a
directory then it is not checked for being busy.

Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2009-12-03 15:58:56 -05:00
Miklos Szeredi e48de5ec25 nfs: remove unnecessary check from nfs_rename()
VFS already checks if both source and target are directories.

Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2009-12-03 15:58:56 -05:00
Trond Myklebust 9c4c761a62 NFSv4.1: Handle NFSv4.1 session errors in the lock recovery code
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2009-12-03 15:58:56 -05:00
Chuck Lever 3a28becc35 SUNRPC: soft connect semantics for UDP
Introduce soft connect behavior for UDP transports.  In this case, a
major timeout returns ETIMEDOUT instead of EIO.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2009-12-03 15:58:56 -05:00
Chuck Lever caabea8a56 SUNRPC: Use soft connect semantics when performing RPC ping
Currently, if a remote RPC service is unreachable, an RPC ping will
hang until the underlying transport connect attempt times out.  A more
desirable behavior might be to have the ping fail immediately so upper
layers can recover appropriately.

In the case of an NFS mount, for instance, this would mean the
mount(2) system call could fail immediately if the server isn't
listening, rather than hanging uninterruptibly for more than 3
minutes.

Change rpc_ping() so that it fails immediately for connection-oriented
transports.  rpc_create() will then fail immediately for such
transports if an RPC ping was requested.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2009-12-03 15:58:56 -05:00
Chuck Lever 012da158f6 SUNRPC: Use soft connects for autobinding over TCP
Autobinding is handled by the rpciod process, not in user processes
that are generating regular RPC requests.  Thus autobinding is usually
not affected by signals targetting user processes, such as KILL or
timer expiration events.

In addition, an RPC request generated by a user process that has
RPC_TASK_SOFTCONN set and needs to perform an autobind will hang if
the remote rpcbind service is not available.

For rpcbind queries on connection-oriented transports, let's use the
new soft connect semantic to return control to the user's process
quickly, if the kernel's rpcbind client can't connect to the remote
rpcbind service.

Logic is introduced in call_bind_status() to handle connection errors
that occurred during an asynchronous rpcbind query.  The logic
abandons the rpcbind query if the RPC request has SOFTCONN set, and
retries after a few seconds in the normal case.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2009-12-03 15:58:56 -05:00
Chuck Lever 2a76b3bfa2 SUNRPC: Use TCP for local rpcbind upcalls
Use TCP with the soft connect semantic for local rpcbind upcalls so
the kernel can detect immediately if the local rpcbind daemon is not
running.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2009-12-03 15:58:56 -05:00
Chuck Lever c526611dd6 SUNRPC: Use a cached RPC client and transport for rpcbind upcalls
The kernel's rpcbind client creates and deletes an rpc_clnt and its
underlying transport socket for every upcall to the local rpcbind
daemon.

When starting a typical NFS server on IPv4 and IPv6, the NFS service
itself does three upcalls (one per version) times two upcalls (one
per transport) times two upcalls (one per address family), making 12,
plus another one for the initial call to unregister previous NFS
services.  Starting the NLM service adds an additional 13 upcalls,
for similar reasons.

(Currently the NFS service doesn't start IPv6 listeners, but it will
soon enough).

Instead, let's create an rpc_clnt for rpcbind upcalls during the
first local rpcbind query, and cache it.  This saves the overhead of
creating and destroying an rpc_clnt and a socket for every upcall.

The new logic also prevents the kernel from attempting an RPCB_SET or
RPCB_UNSET if it knows from the start that the local portmapper does
not support rpcbind protocol version 4.  This will cut down on the
number of rpcbind upcalls in legacy environments.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2009-12-03 15:58:56 -05:00
Chuck Lever 5a46211540 SUNRPC: Simplify synopsis of rpcb_local_clnt()
Clean up: At one point, rpcb_local_clnt() handled IPv6 loopback
addresses too, but it doesn't any more; only IPv4 loopback is used
now.  Get rid of the @addr and @addrlen arguments to
rpcb_local_clnt().

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2009-12-03 15:58:56 -05:00
Chuck Lever 09a21c4102 SUNRPC: Allow RPCs to fail quickly if the server is unreachable
The kernel sometimes makes RPC calls to services that aren't running.
Because the kernel's RPC client always assumes the hard retry semantic
when reconnecting a connection-oriented RPC transport, the underlying
reconnect logic takes a long while to time out, even though the remote
may have responded immediately with ECONNREFUSED.

In certain cases, like upcalls to our local rpcbind daemon, or for NFS
mount requests, we'd like the kernel to fail immediately if the remote
service isn't reachable.  This allows another transport to be tried
immediately, or the pending request can be abandoned quickly.

Introduce a per-request flag which controls how call_transmit_status()
behaves when request transmission fails because the server cannot be
reached.

We don't want soft connection semantics to apply to other errors.  The
default case of the switch statement in call_transmit_status() no
longer falls through; the fall through code is copied to the default
case, and a "break;" is added.

The transport's connection re-establishment timeout is also ignored for
such requests.  We want the request to fail immediately, so the
reconnect delay is skipped.  Additionally, we don't want a connect
failure here to further increase the reconnect timeout value, since
this request will not be retried.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2009-12-03 15:58:56 -05:00
Chuck Lever 206a134b4d SUNRPC: Check explicitly for tk_status == 0 in call_transmit_status()
The success case, where task->tk_status == 0, is by far the most
frequent case in call_transmit_status().

The default: arm of the switch statement in call_transmit_status()
handles the 0 case.  default: was moved close to the top of the switch
statement in call_transmit_status() under the theory that the compiler
places object code for the earliest arms of a switch statement first,
making the CPU do less work.

The default: arm of a switch statement, however, is executed only
after all the other cases have been checked.  Even if the compiler
rearranges the object code, the default: arm is the "last resort",
meaning all of the other cases have been explicitly exhausted.  That
makes the current arrangement about as inefficient as it gets for the
common case.

To fix this, add an explicit check for zero before the switch
statement.  That forces the compiler to do the zero check first, no
matter what optimizations it might try to do to the switch statement.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2009-12-03 15:58:56 -05:00
Chuck Lever dd47f96c07 NFS: Revert default r/wsize behavior
When the "rsize=" or "wsize=" mount options are not specified,
text-based mounts have slightly different behavior than legacy binary
mounts.  Text-based mounts use the smaller of the server's maximum
and the client's maximum, but binary mounts use the smaller of the
server's _preferred_ size and the client's maximum.

This difference is actually pretty subtle.  Most servers advertise
the same value as their maximum and their preferred transfer size, so
the end result is the same in most cases.

The reason for this difference is that for text-based mounts, if
r/wsize are not specified, they are set to the largest value supported
by the client.  For legacy mounts, the values are set to zero if these
options are not specified.

nfs_server_set_fsinfo() can negotiate the transfer size defaults
correctly in any case.  There's no need to specify any particular
value as default in the text-based option parsing logic.

Note that nfs4 doesn't use nfs_server_set_fsinfo(), but the mount.nfs4
command does set rsize and wsize to 0 if the user didn't specify these
options.  So, make the same change for text-based NFSv4 mounts.

Thanks to James Pearson <james-p@moving-picture.com> for reporting and
diagnosing the problem.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2009-12-03 15:58:56 -05:00