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two callback patches

DISCUSSION Jim Rees 3 participants 3 messages Aug 12, 2011 – Aug 14, 2011

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Jim Rees

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#0 lore raw

When you get a chance, could you pull these into pnfs-all-latest? You'll find them on the head of my for-benny branch, and I assume upstream.

commit 3070296f2b3ddc094bda51286c3e9687d59d2a22

Author: Trond Myklebust <[email protected]>
Date:   Tue Aug 2 14:50:40 2011 -0400

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 [email protected] [2.6.38+]
Signed-off-by Trond Myklebust <[email protected]>

commit a8446678ba8b850bcac2286c6ed803c339049096

Author: Trond Myklebust <[email protected]>
Date:   Tue Aug 2 14:50:39 2011 -0400

NFSv4.1: Fix the callback 'highest_used_slotid' behaviour

Currently, there is no guarantee that we will call nfs4_cb_take_slot() even though nfs4_callback_compound() will consistently call nfs4_cb_free_slot() provided the cb_process_state has set the 'clp' field. The result is that we can trigger the BUG_ON() upon the next call to nfs4_cb_take_slot().

This patch fixes the above problem by using the slot id that was taken in the CB_SEQUENCE operation as a flag for whether or not we need to call nfs4_cb_free_slot().
It also fixes an atomicity problem: we need to set tbl->highest_used_slotid atomically with the check for NFS4_SESSION_DRAINING, otherwise we end up racing with the various tests in nfs4_begin_drain_session().

Cc [email protected] [2.6.38+]
Signed-off-by Trond Myklebust <[email protected]>
#1 lore raw
Quoted 3 lines · Jim Rees

When you get a chance, could you pull these into pnfs-all-latest? You'll find them on the head of my for-benny branch, and I assume upstream.

Right and some other bug fixes as well. I find that all of trond/linux-next branch are needed for proper run with v3.1-rc1 stuff. Best is if you can merge in trond/linux-next at the client branch side if the pnfs tree.

Thanks
Boaz

Quoted 47 lines

commit 3070296f2b3ddc094bda51286c3e9687d59d2a22

Author: Trond Myklebust <[email protected]>
Date:   Tue Aug 2 14:50:40 2011 -0400

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 [email protected] [2.6.38+]
Signed-off-by Trond Myklebust <[email protected]>

commit a8446678ba8b850bcac2286c6ed803c339049096

Author: Trond Myklebust <[email protected]>
Date:   Tue Aug 2 14:50:39 2011 -0400

NFSv4.1: Fix the callback 'highest_used_slotid' behaviour

Currently, there is no guarantee that we will call nfs4_cb_take_slot() even though nfs4_callback_compound() will consistently call nfs4_cb_free_slot() provided the cb_process_state has set the 'clp' field. The result is that we can trigger the BUG_ON() upon the next call to nfs4_cb_take_slot().

This patch fixes the above problem by using the slot id that was taken in the CB_SEQUENCE operation as a flag for whether or not we need to call nfs4_cb_free_slot().
It also fixes an atomicity problem: we need to set tbl->highest_used_slotid atomically with the check for NFS4_SESSION_DRAINING, otherwise we end up racing with the various tests in nfs4_begin_drain_session().

Cc [email protected] [2.6.38+]
Signed-off-by Trond Myklebust <[email protected]>

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#2 lore raw
Quoted 8 lines · Boaz Harrosh
Quoted 3 lines · Jim Rees

When you get a chance, could you pull these into pnfs-all-latest? You'll find them on the head of my for-benny branch, and I assume upstream.

Right and some other bug fixes as well. I find that all of trond/linux-next branch are needed for proper run with v3.1-rc1 stuff. Best is if you can merge in trond/linux-next at the client branch side if the pnfs tree.

Yup. I fetched nfs-2.6/bugfixes (same as linux-next as of today) into my nfs-bugfixes branch and released under pnfs-all-3.1-rc1-2011-08-14

Benny

Quoted 56 lines

Thanks
Boaz

Quoted 41 lines

commit 3070296f2b3ddc094bda51286c3e9687d59d2a22

Author: Trond Myklebust <[email protected]>
Date:   Tue Aug 2 14:50:40 2011 -0400

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 [email protected] [2.6.38+]
Signed-off-by Trond Myklebust <[email protected]>

commit a8446678ba8b850bcac2286c6ed803c339049096

Author: Trond Myklebust <[email protected]>
Date:   Tue Aug 2 14:50:39 2011 -0400

NFSv4.1: Fix the callback 'highest_used_slotid' behaviour

Currently, there is no guarantee that we will call nfs4_cb_take_slot() even though nfs4_callback_compound() will consistently call nfs4_cb_free_slot() provided the cb_process_state has set the 'clp' field. The result is that we can trigger the BUG_ON() upon the next call to nfs4_cb_take_slot().

This patch fixes the above problem by using the slot id that was taken in the CB_SEQUENCE operation as a flag for whether or not we need to call nfs4_cb_free_slot().
It also fixes an atomicity problem: we need to set tbl->highest_used_slotid atomically with the check for NFS4_SESSION_DRAINING, otherwise we end up racing with the various tests in nfs4_begin_drain_session().

Quoted 6 lines
Cc [email protected] [2.6.38+]
Signed-off-by Trond Myklebust <[email protected]>

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More majordomo info at http://vger.kernel.org/majordomo-info.html

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