Commit 910ac68a2b80c7de95bc8488734067b1bb15d583
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55a673990e
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NFSv4.1: Return NFS4ERR_BADSESSION to callbacks during session resets
If the client is in the process of resetting the session when it receives a callback, then returning NFS4ERR_DELAY may cause a deadlock with the DESTROY_SESSION call. Basically, if the client returns NFS4ERR_DELAY in response to the CB_SEQUENCE call, then the server is entitled to believe that the client is busy because it is already processing that call. In that case, the server is perfectly entitled to respond with a NFS4ERR_BACK_CHAN_BUSY to any DESTROY_SESSION call. Fix this by having the client reply with a NFS4ERR_BADSESSION in response to the callback if it is resetting the session. Cc: stable@kernel.org [2.6.38+] Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Showing 1 changed file with 5 additions and 0 deletions Side-by-side Diff
fs/nfs/callback_proc.c
| ... | ... | @@ -452,6 +452,11 @@ |
| 452 | 452 | if (test_bit(NFS4_SESSION_DRAINING, &clp->cl_session->session_state)) { |
| 453 | 453 | spin_unlock(&tbl->slot_tbl_lock); |
| 454 | 454 | status = htonl(NFS4ERR_DELAY); |
| 455 | + /* Return NFS4ERR_BADSESSION if we're draining the session | |
| 456 | + * in order to reset it. | |
| 457 | + */ | |
| 458 | + if (test_bit(NFS4CLNT_SESSION_RESET, &clp->cl_state)) | |
| 459 | + status = htonl(NFS4ERR_BADSESSION); | |
| 455 | 460 | goto out; |
| 456 | 461 | } |
| 457 | 462 |