ceph: remove request from unsafe list if it is canceled/timed out

ceph: remove request from unsafe list if it is canceled/timed out

This fixes the list corruption warning like this:

------------[ cut here ]------------
WARNING: at lib/list_debug.c:30 __list_add+0x68/0x81()
Hardware name: X8DTU
list_add corruption. prev->next should be next (ffff880618931250), but was (null). (prev=ffff880c188b9130).
Modules linked in: nfsd lockd nfs_acl auth_rpcgss exportfs ceph libceph libcrc32c sunrpc ipv6 fuse igb i2c_i801 ioatdma i2c_core iTCO_wdt iTCO_vendor_support joydev dca serio_raw usb_storage [last unloaded: scsi_wait_scan]
Pid: 10977, comm: smbd Tainted: G        W  2.6.32.23-170.Elaster.xendom0.fc12.x86_64 #1
Call Trace:
[<ffffffff8105753c>] warn_slowpath_common+0x7c/0x94
[<ffffffff810575ab>] warn_slowpath_fmt+0x41/0x43
[<ffffffff812351a3>] __list_add+0x68/0x81
[<ffffffffa014799d>] ceph_aio_write+0x614/0x8a2 [ceph]
[<ffffffff8111d2a0>] do_sync_write+0xe8/0x125
[<ffffffff81075a1f>] ? autoremove_wake_function+0x0/0x39
[<ffffffff811f21ec>] ? selinux_file_permission+0x5c/0xb3
[<ffffffff811e8521>] ? security_file_permission+0x16/0x18
[<ffffffff8111d864>] vfs_write+0xae/0x10b
[<ffffffff8111d91b>] sys_pwrite64+0x5a/0x76
[<ffffffff81012d32>] system_call_fastpath+0x16/0x1b
---[ end trace 08573eb9f07ff6f4 ]---

Signed-off-by: Henry C Chang <henry_c_chang@tcloudcomputing.com>
Signed-off-by: Sage Weil <sage@newdream.net>