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path: root/fs/nfs/nfs4proc.c
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2019-11-18NFSv4: add declaration of current_stateidBen Dooks1-3/+3
The current_stateid is exported from nfs4state.c but not declared in any of the headers. Add to nfs4_fs.h to remove the following warning: fs/nfs/nfs4state.c:80:20: warning: symbol 'current_stateid' was not declared. Should it be static? Signed-off-by: Ben Dooks <ben.dooks@codethink.co.uk> Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2019-11-13NFSv4.x: Drop the slot if nfs4_delegreturn_prepare waits for layoutreturnTrond Myklebust1-1/+3
If nfs4_delegreturn_prepare needs to wait for a layoutreturn to complete then make sure we drop the sequence slot if we hold it. Fixes: 1c5bd76d17cc ("pNFS: Enable layoutreturn operation for return-on-close") Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2019-11-13NFSv4.x: Handle bad/dead sessions correctly in nfs41_sequence_process()Trond Myklebust1-9/+25
If the server returns a bad or dead session error, the we don't want to update the session slot number, but just immediately schedule recovery and allow it to proceed. We can/should then remove handling in other places Fixes: 3453d5708b33 ("NFSv4.1: Avoid false retries when RPC calls are interrupted") Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2019-11-06Merge branch 'linux-ssc-for-5.5'Trond Myklebust1-3/+4
2019-11-03NFSv4: Don't retry the GETATTR on old stateid in nfs4_delegreturn_done()Trond Myklebust1-0/+4
If the server returns NFS4ERR_OLD_STATEID, then just skip retrying the GETATTR when replaying the delegreturn compound. We know nothing will have changed on the server. Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2019-11-03NFSv4: Handle NFS4ERR_OLD_STATEID in delegreturnTrond Myklebust1-4/+3
If the server returns NFS4ERR_OLD_STATEID in response to our delegreturn, we want to sync to the most recent seqid for the delegation stateid. However if we are already at the most recent, we have two possibilities: - an OPEN reply is still outstanding and will return a new seqid - an earlier OPEN reply was dropped on the floor due to a timeout. In the latter case, we may end up unable to complete the delegreturn, so we want to bump the seqid to a value greater than the cached value. While this may cause us to lose the delegation in the former case, it should now be safe to assume that the client will replay the OPEN if necessary in order to get a new valid stateid. Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2019-11-03NFSv4: nfs4_return_incompatible_delegation() should check delegation validityTrond Myklebust1-1/+1
Ensure that we check that the delegation is valid in nfs4_return_incompatible_delegation() before we try to return it. Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2019-11-03NFSv4: Revoke the delegation on success in nfs4_delegreturn_done()Trond Myklebust1-0/+1
If the delegation was successfully returned, then mark it as revoked. Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2019-11-03NFSv4: Fix delegation handling in update_open_stateid()Trond Myklebust1-2/+2
If the delegation is marked as being revoked, then don't use it in the open state structure. Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2019-11-01NFSv4: Don't allow a cached open with a revoked delegationTrond Myklebust1-5/+2
If the delegation is marked as being revoked, we must not use it for cached opens. Fixes: 869f9dfa4d6d ("NFSv4: Fix races between nfs_remove_bad_delegation() and delegation return") Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com> Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2019-10-10NFSv4: Fix leak of clp->cl_acceptor stringChuck Lever1-0/+1
Our client can issue multiple SETCLIENTID operations to the same server in some circumstances. Ensure that calls to nfs4_proc_setclientid() after the first one do not overwrite the previously allocated cl_acceptor string. unreferenced object 0xffff888461031800 (size 32): comm "mount.nfs", pid 2227, jiffies 4294822467 (age 1407.749s) hex dump (first 32 bytes): 6e 66 73 40 6b 6c 69 6d 74 2e 69 62 2e 31 30 31 nfs@klimt.ib.101 35 67 72 61 6e 67 65 72 2e 6e 65 74 00 00 00 00 5granger.net.... backtrace: [<00000000ab820188>] __kmalloc+0x128/0x176 [<00000000eeaf4ec8>] gss_stringify_acceptor+0xbd/0x1a7 [auth_rpcgss] [<00000000e85e3382>] nfs4_proc_setclientid+0x34e/0x46c [nfsv4] [<000000003d9cf1fa>] nfs40_discover_server_trunking+0x7a/0xed [nfsv4] [<00000000b81c3787>] nfs4_discover_server_trunking+0x81/0x244 [nfsv4] [<000000000801b55f>] nfs4_init_client+0x1b0/0x238 [nfsv4] [<00000000977daf7f>] nfs4_set_client+0xfe/0x14d [nfsv4] [<0000000053a68a2a>] nfs4_create_server+0x107/0x1db [nfsv4] [<0000000088262019>] nfs4_remote_mount+0x2c/0x59 [nfsv4] [<00000000e84a2fd0>] legacy_get_tree+0x2d/0x4c [<00000000797e947c>] vfs_get_tree+0x20/0xc7 [<00000000ecabaaa8>] fc_mount+0xe/0x36 [<00000000f15fafc2>] vfs_kern_mount+0x74/0x8d [<00000000a3ff4e26>] nfs_do_root_mount+0x8a/0xa3 [nfsv4] [<00000000d1c2b337>] nfs4_try_mount+0x58/0xad [nfsv4] [<000000004c9bddee>] nfs_fs_mount+0x820/0x869 [nfs] Fixes: f11b2a1cfbf5 ("nfs4: copy acceptor name from context ... ") Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2019-10-09NFS handle NFS4ERR_PARTNER_NO_AUTH errorOlga Kornievskaia1-0/+1
When a destination server sends a READ to the source server it can get a NFS4ERR_PARTNER_NO_AUTH, which means a copy needs to be restarted. Signed-off-by: Olga Kornievskaia <kolga@netapp.com>
2019-10-09NFS: inter ssc openOlga Kornievskaia1-3/+2
NFSv4.2 inter server to server copy requires the destination server to READ the data from the source server using the provided stateid and file handle. Given an NFSv4 stateid and filehandle from the COPY operaion, provide the destination server with an NFS client function to create a struct file suitable for the destiniation server to READ the data to be copied. Signed-off-by: Olga Kornievskaia <kolga@netapp.com> Signed-off-by: Andy Adamson <andros@netapp.com>
2019-10-09NFS: add COPY_NOTIFY operationOlga Kornievskaia1-0/+1
Try using the delegation stateid, then the open stateid. Only NL4_NETATTR, No support for NL4_NAME and NL4_URL. Allow only one source server address to be returned for now. To distinguish between same server copy offload ("intra") and a copy between different server ("inter"), do a check of server owner identity and also make sure server is capable of doing a copy offload. Signed-off-by: Andy Adamson <andros@netapp.com> Signed-off-by: Olga Kornievskaia <kolga@netapp.com>
2019-09-20NFSv4: Handle NFS4ERR_OLD_STATEID in LOCKUTrond Myklebust1-5/+48
If a LOCKU request receives a NFS4ERR_OLD_STATEID, then bump the seqid before resending. Ensure we only bump the seqid by 1. Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com> Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2019-09-20NFSv4: Handle NFS4ERR_OLD_STATEID in CLOSE/OPEN_DOWNGRADETrond Myklebust1-3/+72
If a CLOSE or OPEN_DOWNGRADE operation receives a NFS4ERR_OLD_STATEID then bump the seqid before resending. Ensure we only bump the seqid by 1. Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com> Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2019-09-20NFSv4: Fix OPEN_DOWNGRADE error handlingTrond Myklebust1-1/+3
If OPEN_DOWNGRADE returns a state error, then we want to initiate state recovery in addition to marking the stateid as closed. Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com> Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2019-09-20pNFS: Handle NFS4ERR_OLD_STATEID on layoutreturn by bumping the state seqidTrond Myklebust1-1/+1
If a LAYOUTRETURN receives a reply of NFS4ERR_OLD_STATEID then assume we've missed an update, and just bump the stateid. Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com> Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2019-09-20NFSv4: Handle RPC level errors in LAYOUTRETURNTrond Myklebust1-0/+9
Handle RPC level errors by assuming that the RPC call was successful. Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com> Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2019-09-20NFSv4: Clean up pNFS return-on-close error handlingTrond Myklebust1-56/+10
Both close and delegreturn have identical code to handle pNFS return-on-close. This patch refactors that code and places it in pnfs.c Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com> Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2019-08-22NFS: Have nfs4_proc_get_lease_time() call nfs4_call_sync_custom()Anna Schumaker1-10/+1
This removes some code duplication, since both functions were doing the same thing. Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2019-08-22NFS: Have nfs41_proc_secinfo_no_name() call nfs4_call_sync_custom()Anna Schumaker1-2/+16
We need to use the custom rpc_task_setup here to set the RPC_TASK_NO_ROUND_ROBIN flag on the RPC call. Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2019-08-22NFS: Have nfs41_proc_reclaim_complete() call nfs4_call_sync_custom()Anna Schumaker1-11/+2
An async call followed by an rpc_wait_for_completion() is basically the same as a synchronous call, so we can use nfs4_call_sync_custom() to keep our custom callback ops and the RPC_TASK_NO_ROUND_ROBIN flag. Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2019-08-22NFS: Have _nfs4_proc_secinfo() call nfs4_call_sync_custom()Anna Schumaker1-8/+21
We do this to set the RPC_TASK_NO_ROUND_ROBIN flag in the task_setup structure Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2019-08-22NFS: Have nfs4_proc_setclientid() call nfs4_call_sync_custom()Anna Schumaker1-8/+2
Rather than running the task manually Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2019-08-22NFS: Add an nfs4_call_sync_custom() functionAnna Schumaker1-10/+15
There are a few cases where we need to manually configure the rpc_task_setup structure to get the behavior we want. Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2019-08-07NFSv4: Ensure state recovery handles ETIMEDOUT correctlyTrond Myklebust1-0/+2
Ensure that the state recovery code handles ETIMEDOUT correctly, and also that we set RPC_TASK_TIMEOUT when recovering open state. Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2019-08-04NFSv4: Fix an Oops in nfs4_do_setattrTrond Myklebust1-1/+1
If the user specifies an open mode of 3, then we don't have a NFSv4 state attached to the context, and so we Oops when we try to dereference it. Reported-by: Olga Kornievskaia <aglo@umich.edu> Fixes: 29b59f9416937 ("NFSv4: change nfs4_do_setattr to take...") Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com> Cc: stable@vger.kernel.org # v4.10: 991eedb1371dc: NFSv4: Only pass the... Cc: stable@vger.kernel.org # v4.10+
2019-08-04NFSv4: Check the return value of update_open_stateid()Trond Myklebust1-4/+8
Ensure that we always check the return value of update_open_stateid() so that we can retry if the update of local state failed. This fixes infinite looping on state recovery. Fixes: e23008ec81ef3 ("NFSv4 reduce attribute requests for open reclaim") Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com> Cc: stable@vger.kernel.org # v3.7+
2019-08-04NFSv4.1: Fix open stateid recoveryTrond Myklebust1-27/+38
The logic for checking in nfs41_check_open_stateid() whether the state is supported by a delegation is inverted. In addition, it makes more sense to perform that check before we check for expired locks. Fixes: 8a64c4ef106d1 ("NFSv4.1: Even if the stateid is OK,...") Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2019-08-04NFSv4: Fix delegation state recoveryTrond Myklebust1-13/+12
Once we clear the NFS_DELEGATED_STATE flag, we're telling nfs_delegation_claim_opens() that we're done recovering all open state for that stateid, so we really need to ensure that we test for all open modes that are currently cached and recover them before exiting nfs4_open_delegation_recall(). Fixes: 24311f884189d ("NFSv4: Recovery of recalled read delegations...") Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com> Cc: stable@vger.kernel.org # v4.3+
2019-08-04NFSv4: Fix a credential refcount leak in nfs41_check_delegation_stateidTrond Myklebust1-2/+1
It is unsafe to dereference delegation outside the rcu lock, and in any case, the refcount is guaranteed held if cred is non-zero. Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2019-07-18SUNRPC: Fix up backchannel slot table accountingTrond Myklebust1-0/+3
Add a per-transport maximum limit in the socket case, and add helpers to allow the NFSv4 code to discover that limit. Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2019-07-15NFSv4: Validate the stateid before applying it to state recoveryTrond Myklebust1-2/+19
If the stateid is the zero or invalid stateid, then it is pointless to attempt to use it for recovery. In that case, try to fall back to using the open state stateid, or just doing a general recovery of all state on a given inode. Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2019-07-13nfs4: Make nfs4_proc_get_lease_time available for nfs4.0Donald Buczek1-1/+5
Compile nfs4_proc_get_lease_time, enc_get_lease_time and dec_get_lease_time for nfs4.0. Use nfs4_sequence_done instead of nfs41_sequence_done in nfs4_proc_get_lease_time, Signed-off-by: Donald Buczek <buczek@molgen.mpg.de> Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2019-07-06NFS: send state management on a single connection.NeilBrown1-9/+13
With NFSv4.1, different network connections need to be explicitly bound to a session. During session startup, this is not possible so only a single connection must be used for session startup. So add a task flag to disable the default round-robin choice of connections (when nconnect > 1) and force the use of a single connection. Then use that flag on all requests for session management - for consistence, include NFSv4.0 management (SETCLIENTID) and session destruction Reported-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: NeilBrown <neilb@suse.com> Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2019-07-06NFSv4: Handle open for execute correctlyTrond Myklebust1-8/+20
When mapping the NFSv4 context to an open mode and access mode, we need to treat the FMODE_EXEC flag differently. For the open mode, FMODE_EXEC means we need read share access. For the access mode checking, we need to verify that the user actually has execute access. Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2019-06-21NFS4: Only set creation opendata if O_CREATBenjamin Coddington1-9/+11
We can end up in nfs4_opendata_alloc during task exit, in which case current->fs has already been cleaned up. This leads to a crash in current_umask(). Fix this by only setting creation opendata if we are actually doing an open with O_CREAT. We can drop the check for NULL nfs4_open_createattrs, since O_CREAT will never be set for the recovery path. Suggested-by: Trond Myklebust <trondmy@hammerspace.com> Signed-off-by: Benjamin Coddington <bcodding@redhat.com> Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2019-05-30NFSv4.1: Fix bug only first CB_NOTIFY_LOCK is handledYihao Wu1-3/+5
When a waiter is waked by CB_NOTIFY_LOCK, it will retry nfs4_proc_setlk(). The waiter may fail to nfs4_proc_setlk() and sleep again. However, the waiter is already removed from clp->cl_lock_waitq when handling CB_NOTIFY_LOCK in nfs4_wake_lock_waiter(). So any subsequent CB_NOTIFY_LOCK won't wake this waiter anymore. We should put the waiter back to clp->cl_lock_waitq before retrying. Cc: stable@vger.kernel.org #4.9+ Signed-off-by: Yihao Wu <wuyihao@linux.alibaba.com> Reviewed-by: Jeff Layton <jlayton@kernel.org> Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2019-05-30NFSv4.1: Again fix a race where CB_NOTIFY_LOCK fails to wake a waiterYihao Wu1-17/+7
Commit b7dbcc0e433f "NFSv4.1: Fix a race where CB_NOTIFY_LOCK fails to wake a waiter" found this bug. However it didn't fix it. This commit replaces schedule_timeout() with wait_woken() and default_wake_function() with woken_wake_function() in function nfs4_retry_setlk() and nfs4_wake_lock_waiter(). wait_woken() uses memory barriers in its implementation to avoid potential race condition when putting a process into sleeping state and then waking it up. Fixes: a1d617d8f134 ("nfs: allow blocking locks to be awoken by lock callbacks") Cc: stable@vger.kernel.org #4.9+ Signed-off-by: Yihao Wu <wuyihao@linux.alibaba.com> Reviewed-by: Jeff Layton <jlayton@kernel.org> Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2019-04-25NFS: Allow signal interruption of NFS4ERR_DELAYed operationsTrond Myklebust1-34/+105
If the server is unable to immediately execute an RPC call, and returns an NFS4ERR_DELAY then we can assume it is safe to interrupt the operation in order to handle ordinary signals. This allows the application to service timer interrupts that would otherwise have to wait until the server is again able to respond. Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com> Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2019-04-25SUNRPC: Add function rpc_sleep_on_timeout()Trond Myklebust1-6/+12
Clean up the RPC task sleep interfaces by replacing the task->tk_timeout 'hidden parameter' to rpc_sleep_on() with a new function that takes an absolute timeout. Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com> Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2019-04-25SUNRPC: Remove unused argument 'action' from rpc_sleep_on_priority()Trond Myklebust1-1/+1
None of the callers set the 'action' argument, so let's just remove it. Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com> Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2019-03-19NFSv4.1 don't free interrupted slot on openOlga Kornievskaia1-1/+2
Allow the async rpc task for finish and update the open state if needed, then free the slot. Otherwise, the async rpc unable to decode the reply. Signed-off-by: Olga Kornievskaia <kolga@netapp.com> Fixes: ae55e59da0e4 ("pnfs: Don't release the sequence slot...") Cc: stable@vger.kernel.org # v4.18+ Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2019-03-18NFS: Fix nfs4_lock_state refcounting in nfs4_alloc_{lock,unlock}data()Catalin Marinas1-2/+0
Commit 7b587e1a5a6c ("NFS: use locks_copy_lock() to copy locks.") changed the lock copying from memcpy() to the dedicated locks_copy_lock() function. The latter correctly increments the nfs4_lock_state.ls_count via nfs4_fl_copy_lock(), however, this refcount has already been incremented in the nfs4_alloc_{lock,unlock}data(). Kmemleak subsequently reports an unreferenced nfs4_lock_state object as below (arm64 platform): unreferenced object 0xffff8000fce0b000 (size 256): comm "systemd-sysuser", pid 1608, jiffies 4294892825 (age 32.348s) hex dump (first 32 bytes): 20 57 4c fb 00 80 ff ff 20 57 4c fb 00 80 ff ff WL..... WL..... 00 57 4c fb 00 80 ff ff 01 00 00 00 00 00 00 00 .WL............. backtrace: [<000000000d15010d>] kmem_cache_alloc+0x178/0x208 [<00000000d7c1d264>] nfs4_set_lock_state+0x124/0x1f0 [<000000009c867628>] nfs4_proc_lock+0x90/0x478 [<000000001686bd74>] do_setlk+0x64/0xe8 [<00000000e01500d4>] nfs_lock+0xe8/0x1f0 [<000000004f387d8d>] vfs_lock_file+0x18/0x40 [<00000000656ab79b>] do_lock_file_wait+0x68/0xf8 [<00000000f17c4a4b>] fcntl_setlk+0x224/0x280 [<0000000052a242c6>] do_fcntl+0x418/0x730 [<000000004f47291a>] __arm64_sys_fcntl+0x84/0xd0 [<00000000d6856e01>] el0_svc_common+0x80/0xf0 [<000000009c4bd1df>] el0_svc_handler+0x2c/0x80 [<00000000b1a0d479>] el0_svc+0x8/0xc [<0000000056c62a0f>] 0xffffffffffffffff This patch removes the original refcount_inc(&lsp->ls_count) that was paired with the memcpy() lock copying. Fixes: 7b587e1a5a6c ("NFS: use locks_copy_lock() to copy locks.") Cc: <stable@vger.kernel.org> # 5.0.x- Cc: NeilBrown <neilb@suse.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2019-03-01NFSv4: Handle early exit in layoutget by returning an errorTrond Myklebust1-2/+4
If the LAYOUTGET rpc call exits early without an error, convert it to EAGAIN. Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2019-03-01NFSv4.2: Add client support for the generic 'layouterror' RPC callTrond Myklebust1-1/+2
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2019-03-01NFSv4.1: Don't process the sequence op more than once.Trond Myklebust1-1/+1
Ensure that if we call nfs41_sequence_process() a second time for the same rpc_task, then we only process the results once. Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2019-03-01NFSv4.1: Reinitialise sequence results before retransmitting a requestTrond Myklebust1-4/+8
If we have to retransmit a request, we should ensure that we reinitialise the sequence results structure, since in the event of a signal we need to treat the request as if it had not been sent. Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com> Cc: stable@vger.kernel.org
2019-02-21NFSv4.1: Avoid false retries when RPC calls are interruptedTrond Myklebust1-57/+48
A 'false retry' in NFSv4.1 occurs when the client attempts to transmit a new RPC call using a slot+sequence number combination that references an already cached one. Currently, the Linux NFS client will do this if a user process interrupts an RPC call that is in progress. The problem with doing so is that we defeat the main mechanism used by the server to differentiate between a new call and a replayed one. Even if the server is able to perfectly cache the arguments of the old call, it cannot know if the client intended to replay or send a new call. The obvious fix is to bump the sequence number pre-emptively if an RPC call is interrupted, but in order to deal with the corner cases where the interrupted call is not actually received and processed by the server, we need to interpret the error NFS4ERR_SEQ_MISORDERED as a sign that we need to either wait or locate a correct sequence number that lies between the value we sent, and the last value that was acked by a SEQUENCE call on that slot. Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com> Tested-by: Jason Tibbitts <tibbs@math.uh.edu>