From 4a82fd7c4e78a1b7a224f9ae8bb7e1fd95f670e0 Mon Sep 17 00:00:00 2001 From: Andy Adamson Date: Fri, 15 Nov 2013 16:36:16 -0500 Subject: [PATCH] NFSv4 wait on recovery for async session errors When the state manager is processing the NFS4CLNT_DELEGRETURN flag, session draining is off, but DELEGRETURN can still get a session error. The async handler calls nfs4_schedule_session_recovery returns -EAGAIN, and the DELEGRETURN done then restarts the RPC task in the prepare state. With the state manager still processing the NFS4CLNT_DELEGRETURN flag with session draining off, these DELEGRETURNs will cycle with errors filling up the session slots. This prevents OPEN reclaims (from nfs_delegation_claim_opens) required by the NFS4CLNT_DELEGRETURN state manager processing from completing, hanging the state manager in the __rpc_wait_for_completion_task in nfs4_run_open_task as seen in this kernel thread dump: kernel: 4.12.32.53-ma D 0000000000000000 0 3393 2 0x00000000 kernel: ffff88013995fb60 0000000000000046 ffff880138cc5400 ffff88013a9df140 kernel: ffff8800000265c0 ffffffff8116eef0 ffff88013fc10080 0000000300000001 kernel: ffff88013a4ad058 ffff88013995ffd8 000000000000fbc8 ffff88013a4ad058 kernel: Call Trace: kernel: [] ? cache_alloc_refill+0x1c0/0x240 kernel: [] ? rpc_wait_bit_killable+0x0/0xa0 [sunrpc] kernel: [] rpc_wait_bit_killable+0x42/0xa0 [sunrpc] kernel: [] __wait_on_bit+0x5f/0x90 kernel: [] ? rpc_wait_bit_killable+0x0/0xa0 [sunrpc] kernel: [] out_of_line_wait_on_bit+0x78/0x90 kernel: [] ? wake_bit_function+0x0/0x50 kernel: [] __rpc_wait_for_completion_task+0x2d/0x30 [sunrpc] kernel: [] nfs4_run_open_task+0x11c/0x160 [nfs] kernel: [] nfs4_open_recover_helper+0x87/0x120 [nfs] kernel: [] nfs4_open_recover+0xc6/0x150 [nfs] kernel: [] ? nfs4_open_recoverdata_alloc+0x2f/0x60 [nfs] kernel: [] nfs4_open_delegation_recall+0x6a/0xa0 [nfs] kernel: [] nfs_end_delegation_return+0x120/0x2e0 [nfs] kernel: [] ? queue_work+0x1f/0x30 kernel: [] nfs_client_return_marked_delegations+0xd7/0x110 [nfs] kernel: [] nfs4_run_state_manager+0x548/0x620 [nfs] kernel: [] ? nfs4_run_state_manager+0x0/0x620 [nfs] kernel: [] kthread+0x96/0xa0 kernel: [] child_rip+0xa/0x20 kernel: [] ? kthread+0x0/0xa0 kernel: [] ? child_rip+0x0/0x20 The state manager can not therefore process the DELEGRETURN session errors. Change the async handler to wait for recovery on session errors. Signed-off-by: Andy Adamson Cc: stable@vger.kernel.org Signed-off-by: Trond Myklebust --- fs/nfs/nfs4proc.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c index 5ab33c0792df..1f4edfbb4a70 100644 --- a/fs/nfs/nfs4proc.c +++ b/fs/nfs/nfs4proc.c @@ -4803,7 +4803,7 @@ nfs4_async_handle_error(struct rpc_task *task, const struct nfs_server *server, dprintk("%s ERROR %d, Reset session\n", __func__, task->tk_status); nfs4_schedule_session_recovery(clp->cl_session, task->tk_status); - goto restart_call; + goto wait_on_recovery; #endif /* CONFIG_NFS_V4_1 */ case -NFS4ERR_DELAY: nfs_inc_server_stats(server, NFSIOS_DELAY); -- 2.30.2