From c035362eb935fe9381d9d1cc453bc2a37460e24c Mon Sep 17 00:00:00 2001 From: Chuck Lever Date: Thu, 8 Sep 2022 18:14:00 -0400 Subject: NFSD: Add a mechanism to wait for a DELEGRETURN Subsequent patches will use this mechanism to wake up an operation that is waiting for a client to return a delegation. The new tracepoint records whether the wait timed out or was properly awoken by the expected DELEGRETURN: nfsd-1155 [002] 83799.493199: nfsd_delegret_wakeup: xid=0x14b7d6ef fh_hash=0xf6826792 (timed out) Suggested-by: Jeff Layton Signed-off-by: Chuck Lever Reviewed-by: Jeff Layton --- fs/nfsd/nfs4state.c | 30 ++++++++++++++++++++++++++++++ 1 file changed, 30 insertions(+) (limited to 'fs/nfsd/nfs4state.c') diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c index 561f3556b1d2..54bc70427ce3 100644 --- a/fs/nfsd/nfs4state.c +++ b/fs/nfsd/nfs4state.c @@ -4717,6 +4717,35 @@ nfs4_share_conflict(struct svc_fh *current_fh, unsigned int deny_type) return ret; } +static bool nfsd4_deleg_present(const struct inode *inode) +{ + struct file_lock_context *ctx = smp_load_acquire(&inode->i_flctx); + + return ctx && !list_empty_careful(&ctx->flc_lease); +} + +/** + * nfsd_wait_for_delegreturn - wait for delegations to be returned + * @rqstp: the RPC transaction being executed + * @inode: in-core inode of the file being waited for + * + * The timeout prevents deadlock if all nfsd threads happen to be + * tied up waiting for returning delegations. + * + * Return values: + * %true: delegation was returned + * %false: timed out waiting for delegreturn + */ +bool nfsd_wait_for_delegreturn(struct svc_rqst *rqstp, struct inode *inode) +{ + long __maybe_unused timeo; + + timeo = wait_var_event_timeout(inode, !nfsd4_deleg_present(inode), + NFSD_DELEGRETURN_TIMEOUT); + trace_nfsd_delegret_wakeup(rqstp, inode, timeo); + return timeo > 0; +} + static void nfsd4_cb_recall_prepare(struct nfsd4_callback *cb) { struct nfs4_delegation *dp = cb_to_delegation(cb); @@ -6779,6 +6808,7 @@ nfsd4_delegreturn(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate, if (status) goto put_stateid; + wake_up_var(d_inode(cstate->current_fh.fh_dentry)); destroy_delegation(dp); put_stateid: nfs4_put_stid(&dp->dl_stid); -- cgit