From fd19ca36fd782b84f71b86525b91a905cda913a4 Mon Sep 17 00:00:00 2001 From: Dai Ngo Date: Thu, 29 Jun 2023 18:52:39 -0700 Subject: NFSD: handle GETATTR conflict with write delegation If the GETATTR request on a file that has write delegation in effect and the request attributes include the change info and size attribute then the write delegation is recalled. If the delegation is returned within 30ms then the GETATTR is serviced as normal otherwise the NFS4ERR_DELAY error is returned for the GETATTR. Add counter for write delegation recall due to conflict GETATTR. This is used to evaluate the need to implement CB_GETATTR to adoid recalling the delegation with conflit GETATTR. Signed-off-by: Dai Ngo Signed-off-by: Chuck Lever --- fs/nfsd/nfs4state.c | 65 +++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 65 insertions(+) (limited to 'fs/nfsd/nfs4state.c') diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c index daf305daa751..b56ea72d4350 100644 --- a/fs/nfsd/nfs4state.c +++ b/fs/nfsd/nfs4state.c @@ -8341,3 +8341,68 @@ nfsd4_get_writestateid(struct nfsd4_compound_state *cstate, { get_stateid(cstate, &u->write.wr_stateid); } + +/** + * nfsd4_deleg_getattr_conflict - Recall if GETATTR causes conflict + * @rqstp: RPC transaction context + * @inode: file to be checked for a conflict + * + * This function is called when there is a conflict between a write + * delegation and a change/size GETATTR from another client. The server + * must either use the CB_GETATTR to get the current values of the + * attributes from the client that holds the delegation or recall the + * delegation before replying to the GETATTR. See RFC 8881 section + * 18.7.4. + * + * The current implementation does not support CB_GETATTR yet. However + * this can avoid recalling the delegation could be added in follow up + * work. + * + * Returns 0 if there is no conflict; otherwise an nfs_stat + * code is returned. + */ +__be32 +nfsd4_deleg_getattr_conflict(struct svc_rqst *rqstp, struct inode *inode) +{ + __be32 status; + struct file_lock_context *ctx; + struct file_lock *fl; + struct nfs4_delegation *dp; + + ctx = locks_inode_context(inode); + if (!ctx) + return 0; + spin_lock(&ctx->flc_lock); + list_for_each_entry(fl, &ctx->flc_lease, fl_list) { + if (fl->fl_flags == FL_LAYOUT) + continue; + if (fl->fl_lmops != &nfsd_lease_mng_ops) { + /* + * non-nfs lease, if it's a lease with F_RDLCK then + * we are done; there isn't any write delegation + * on this inode + */ + if (fl->fl_type == F_RDLCK) + break; + goto break_lease; + } + if (fl->fl_type == F_WRLCK) { + dp = fl->fl_owner; + if (dp->dl_recall.cb_clp == *(rqstp->rq_lease_breaker)) { + spin_unlock(&ctx->flc_lock); + return 0; + } +break_lease: + spin_unlock(&ctx->flc_lock); + nfsd_stats_wdeleg_getattr_inc(); + status = nfserrno(nfsd_open_break_lease(inode, NFSD_MAY_READ)); + if (status != nfserr_jukebox || + !nfsd_wait_for_delegreturn(rqstp, inode)) + return status; + return 0; + } + break; + } + spin_unlock(&ctx->flc_lock); + return 0; +} -- cgit v1.2.3