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NFSv4/pnfs: Dispatch CB_NOTIFY_DEVICEID DELETE to race recovery

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Turn on the RFC 8881 Section 18.40.4 DELETE handling: a DELETE for a
deviceID that no live layout references keeps today's cheap behavior
(drop the cached device, no state-manager wake).  A DELETE for a
deviceID that live layouts still reference is deferred to the state
manager, which TEST_STATEIDs the referring layouts, recovers revoked
ones, and confirms or refutes the delete with GETDEVICEINFO.

The deferred case no longer unhashes the device immediately: if the
recovery concludes the DELETE was erroneous (the deviceID still
exists and a referring layout is still valid), the client keeps
using the cached device.

Re-arm the state manager afterwards, as the delegation return above it
does.  The recovery issues synchronous RPCs, and a manager thread that
starts and exits while it runs clears NFS4CLNT_RUN_MANAGER on its way
out.

Bump the deviceid change epoch for both notification types rather
than only for CHANGE.  A GETDEVICEINFO whose reply is already in
flight can otherwise re-cache a device the notification has just
invalidated; that is as true of a delete as of a change, and Section
18.40.4 opens by describing the race for the delete case.

Assisted-by: Claude:claude-fable-5
Signed-off-by: Benjamin Coddington <bcodding@hammerspace.com>
Signed-off-by: Anna Schumaker <anna.schumaker@hammerspace.com>
This commit is contained in:
Benjamin Coddington 2026-09-15 08:22:22 -04:00 committed by Anna Schumaker
parent 14286f49f0
commit db485e0625
2 changed files with 18 additions and 10 deletions
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24
fs/nfs/callback_proc.c
View File

@ -392,19 +392,25 @@ __be32 nfs4_callback_devicenotify(void *argp, void *resp,
continue;
}
/*
* Unhash the cached device first so re-resolution cannot
* re-pin the stale node, then re-point any references
* pinned under live layouts (RFC 8881 Section 12.2.10).
* The epoch bump lets an in-flight GETDEVICEINFO detect
* that its reply may predate the change.
* Bump the epoch before touching the cache so a
* GETDEVICEINFO already in flight can detect that it
* predates the notification. A referenced DELETE may be
* racing revocation, so defer it to the state manager --
* this thread cannot issue fore-channel RPCs.
*/
if (dev->cbd_notify_type == NOTIFY_DEVICEID4_CHANGE)
nfs4_deviceid_bump_change_epoch(cps->clp);
nfs4_delete_deviceid(ld, cps->clp, &dev->cbd_dev_id);
if (dev->cbd_notify_type == NOTIFY_DEVICEID4_CHANGE)
nfs4_deviceid_bump_change_epoch(cps->clp);
if (dev->cbd_notify_type == NOTIFY_DEVICEID4_CHANGE) {
nfs4_delete_deviceid(ld, cps->clp, &dev->cbd_dev_id);
pnfs_layout_reresolve_deviceid_byclid(cps->clp, ld,
&dev->cbd_dev_id,
dev->cbd_immediate);
} else if (pnfs_layout_deviceid_referenced_byclid(cps->clp,
ld, &dev->cbd_dev_id)) {
pnfs_deviceid_delete_mark(cps->clp, ld,
&dev->cbd_dev_id);
} else {
nfs4_delete_deviceid(ld, cps->clp, &dev->cbd_dev_id);
}
}
pnfs_put_layoutdriver(ld);
out:

4
fs/nfs/nfs4state.c
View File

@ -2670,8 +2670,10 @@ static void nfs4_state_manager(struct nfs_client *clp)
}
nfs4_layoutreturn_any_run(clp);
if (test_and_clear_bit(NFS4CLNT_DEVICEID_DELETE,
&clp->cl_state))
&clp->cl_state)) {
nfs4_deviceid_delete_recover_run(clp);
set_bit(NFS4CLNT_RUN_MANAGER, &clp->cl_state);
}
clear_bit(NFS4CLNT_RECALL_RUNNING, &clp->cl_state);
}