On Thu, 2010-07-22 at 15:36 +0800, Wu Fengguang wrote: > Hi Trond, > > May I ask you an NFS question? I got a bit puzzled by this call trace. It > happens after stopping the nfsd at server side when the client side is > doing cp over NFSv3: > > [49388.040091] cp D 0000000000000082 2968 2782 28204 0x00000000 > [49388.040097] ffff8800b8587778 0000000000000002 ffff8800b85877f8 00000000001d4e40 > [49388.040103] ffff8800b8587fd8 00000000001d4e40 ffff8800b8587fd8 ffff8800b8ec4700 > [49388.040110] 00000000001d4e40 ffff8800b8587fd8 00000000001d4e40 00000000001d4e40 > [49388.040116] Call Trace: > [49388.040121] [<ffffffff810de503>] ? prepare_to_wait+0x73/0xc0 > [49388.040127] [<ffffffff81b32750>] ? rpc_wait_bit_killable+0x0/0x60 > [49388.040132] [<ffffffff81b3277f>] rpc_wait_bit_killable+0x2f/0x60 > [49388.040136] [<ffffffff81babded>] __wait_on_bit+0x8d/0xe0 > [49388.040140] [<ffffffff81b32750>] ? rpc_wait_bit_killable+0x0/0x60 > [49388.040144] [<ffffffff81babec6>] out_of_line_wait_on_bit+0x86/0xa0 > [49388.040149] [<ffffffff810de170>] ? wake_bit_function+0x0/0x70 > [49388.040154] [<ffffffff81b333bf>] __rpc_execute+0x16f/0x3f0 > [49388.040158] [<ffffffff81b3367b>] rpc_execute+0x3b/0x50 > [49388.040162] [<ffffffff81b28d31>] rpc_run_task+0x51/0xc0 > [49388.040167] [<ffffffff81366ad6>] nfs_commit_list+0x1f6/0x3e0 > [49388.040172] [<ffffffff81366de9>] nfs_commit_inode+0x129/0x170 > [49388.040176] [<ffffffff813677fa>] nfs_write_inode+0x7a/0xf0 > [49388.040180] [<ffffffff81239a8b>] writeback_single_inode+0x28b/0x3f0 > [49388.040186] [<ffffffff8123ac08>] writeback_inodes_wb+0x318/0x650 > [49388.040191] [<ffffffff8123b1d2>] writeback_inodes_wbc+0x22/0x30 > [49388.040196] [<ffffffff811a5a00>] balance_dirty_pages_ratelimited_nr+0x400/0x5d0 > [49388.040202] [<ffffffff81196306>] ? iov_iter_copy_from_user_atomic+0xa6/0x1c0 > [49388.040207] [<ffffffff81196898>] generic_file_buffered_write+0x258/0x370 > [49388.040213] [<ffffffff81199b7a>] __generic_file_aio_write+0x2ea/0x5f0 > [49388.040218] [<ffffffff81bad374>] ? mutex_lock_nested+0x394/0x530 > [49388.040223] [<ffffffff81199edf>] ? generic_file_aio_write+0x5f/0x100 > [49388.040229] [<ffffffff81199ef9>] generic_file_aio_write+0x79/0x100 > [49388.040235] [<ffffffff81353f00>] nfs_file_write+0xe0/0x2a0 > [49388.040240] [<ffffffff8120a138>] do_sync_write+0xe8/0x140 > [49388.040246] [<ffffffff811bd7b6>] ? might_fault+0xd6/0xf0 > [49388.040251] [<ffffffff8120b156>] vfs_write+0xb6/0x220 > [49388.040255] [<ffffffff8120b406>] sys_write+0x66/0xb0 > [49388.040260] [<ffffffff8104ab72>] system_call_fastpath+0x16/0x1b > > >From simple code review I cannot explain why out_of_line_wait_on_bit() > is called inside __rpc_execute() for a commit request. > > nfs_commit_rpcsetup() sets RPC_TASK_ASYNC for task_setup_data.flags, > which is transferred to task->tk_flags in rpc_init_task(). > __rpc_execute() should then return on task_is_async=1 and skip the > out_of_line_wait_on_bit() call. However the trace shows that > out_of_line_wait_on_bit() is called. I'm a bit puzzled. I must have > missed something. Is this the expected behavior? Hi Fengguang, Are you sure this trace is from a recent kernel? In all kernels prior to 2.6.34-rc3, COMMIT was a synchronous RPC call, which would explain the above trace. Cheers Trond -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
