smb request is blocked after calling close function when network is lost

My application was writing data to a cifs filesystem, when the file was written completely, it called close, at this time, the network is lost. the close calling was blocked. this is log in dmesg:

[  +0.006721] INFO: task filesync:4190 blocked for more than 120 seconds.
[  +0.007361] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables 
this message.
[  +0.008557] filesync        D ffff880211d07da0     0  4190      1 0x00000000
[  +0.007803]  ffff880211d07c40 0000000000000082 ffff880211bfdc00 ffff880211d07fd8
[  +0.008247]  ffff880211d07fd8 ffff880211d07fd8 ffff880211bfdc00 ffff88021f294780
[  +0.008190]  0000000000000000 7fffffffffffffff ffffffff811688b0 ffff880211d07da0
[  +0.008169] Call Trace:
[  +0.003108]  [<ffffffff811688b0>] ? wait_on_page_read+0x60/0x60
[  +0.006617]  [<ffffffff8163a909>] schedule+0x29/0x70
[  +0.005668]  [<ffffffff816385f9>] schedule_timeout+0x209/0x2d0
[  +0.006535]  [<ffffffff8150f751>] ? kernel_setsockopt+0x31/0x50
[  +0.006601]  [<ffffffffa0672c9d>] ? smb_send_rqst+0x17d/0x2a0 [cifs]
[  +0.007023]  [<ffffffff8101c829>] ? read_tsc+0x9/0x10
[  +0.005687]  [<ffffffff811688b0>] ? wait_on_page_read+0x60/0x60
[  +0.006588]  [<ffffffff81639f3e>] io_schedule_timeout+0xae/0x130
[  +0.006678]  [<ffffffff81639fd8>] io_schedule+0x18/0x20
[  +0.005892]  [<ffffffff811688be>] sleep_on_page+0xe/0x20
[  +0.005952]  [<ffffffff81638780>] __wait_on_bit+0x60/0x90
[  +0.006014]  [<ffffffff81168646>] wait_on_page_bit+0x86/0xb0
[  +0.006278]  [<ffffffff810a6b60>] ? wake_atomic_t_function+0x40/0x40
[  +0.007080]  [<ffffffff81168781>] filemap_fdatawait_range+0x111/0x1b0
[  +0.007073]  [<ffffffff811758fe>] ? do_writepages+0x1e/0x40
[  +0.006202]  [<ffffffff8116a685>] ? __filemap_fdatawrite_range+0x65/0x80
[  +0.007325]  [<ffffffff81168847>] filemap_fdatawait+0x27/0x30
[  +0.006369]  [<ffffffff8116a70b>] filemap_write_and_wait+0x3b/0x60
[  +0.006798]  [<ffffffffa0669ad1>] cifs_flush+0x41/0x70 [cifs]
[  +0.006358]  [<ffffffff811dc254>] filp_close+0x34/0x80
[  +0.005769]  [<ffffffff811fcb98>] __close_fd+0x78/0xa0
[  +0.005758]  [<ffffffff811dd963>] SyS_close+0x23/0x50
[  +0.005666]  [<ffffffff81645909>] system_call_fastpath+0x16/0x1b

After this message, the system can't work normally. in the log, smb request is blocked, how to avoid it?