On Fri, Jul 28, 2023 at 08:44:04PM +0200, Lorenzo Bianconi wrote: > Introduce rpc_status entry in nfsd debug filesystem in order to dump > pending RPC requests debugging information. > > Link: https://bugzilla.linux-nfs.org/show_bug.cgi?id=366 > Signed-off-by: Lorenzo Bianconi <lorenzo@xxxxxxxxxx> > --- > fs/nfsd/nfs4proc.c | 4 +- > fs/nfsd/nfsctl.c | 10 +++ > fs/nfsd/nfsd.h | 2 + > fs/nfsd/nfssvc.c | 122 +++++++++++++++++++++++++++++++++++++ > include/linux/sunrpc/svc.h | 1 + > net/sunrpc/svc.c | 2 +- > 6 files changed, 137 insertions(+), 4 deletions(-) > > diff --git a/fs/nfsd/nfs4proc.c b/fs/nfsd/nfs4proc.c > index f0f318e78630..b7ad3081bc36 100644 > --- a/fs/nfsd/nfs4proc.c > +++ b/fs/nfsd/nfs4proc.c > @@ -2497,8 +2497,6 @@ static inline void nfsd4_increment_op_stats(u32 opnum) > > static const struct nfsd4_operation nfsd4_ops[]; > > -static const char *nfsd4_op_name(unsigned opnum); > - > /* > * Enforce NFSv4.1 COMPOUND ordering rules: > * > @@ -3628,7 +3626,7 @@ void warn_on_nonidempotent_op(struct nfsd4_op *op) > } > } > > -static const char *nfsd4_op_name(unsigned opnum) > +const char *nfsd4_op_name(unsigned opnum) > { > if (opnum < ARRAY_SIZE(nfsd4_ops)) > return nfsd4_ops[opnum].op_name; > diff --git a/fs/nfsd/nfsctl.c b/fs/nfsd/nfsctl.c > index 35d2e2cde1eb..f2e4f4b1e4d1 100644 > --- a/fs/nfsd/nfsctl.c > +++ b/fs/nfsd/nfsctl.c > @@ -57,6 +57,8 @@ enum { > NFSD_RecoveryDir, > NFSD_V4EndGrace, > #endif > + NFSD_Rpc_Status, > + > NFSD_MaxReserved > }; > > @@ -195,6 +197,13 @@ static inline struct net *netns(struct file *file) > return file_inode(file)->i_sb->s_fs_info; > } > > +static const struct file_operations nfsd_rpc_status_operations = { > + .open = nfsd_rpc_status_open, > + .read = seq_read, > + .llseek = seq_lseek, > + .release = nfsd_pool_stats_release, > +}; > + > /* > * write_unlock_ip - Release all locks used by a client > * > @@ -1400,6 +1409,7 @@ static int nfsd_fill_super(struct super_block *sb, struct fs_context *fc) > [NFSD_RecoveryDir] = {"nfsv4recoverydir", &transaction_ops, S_IWUSR|S_IRUSR}, > [NFSD_V4EndGrace] = {"v4_end_grace", &transaction_ops, S_IWUSR|S_IRUGO}, > #endif > + [NFSD_Rpc_Status] = {"rpc_status", &nfsd_rpc_status_operations, S_IRUGO}, > /* last one */ {""} > }; > > diff --git a/fs/nfsd/nfsd.h b/fs/nfsd/nfsd.h > index d88498f8b275..75a3e1d55bc8 100644 > --- a/fs/nfsd/nfsd.h > +++ b/fs/nfsd/nfsd.h > @@ -94,6 +94,7 @@ int nfsd_get_nrthreads(int n, int *, struct net *); > int nfsd_set_nrthreads(int n, int *, struct net *); > int nfsd_pool_stats_open(struct inode *, struct file *); > int nfsd_pool_stats_release(struct inode *, struct file *); > +int nfsd_rpc_status_open(struct inode *inode, struct file *file); > void nfsd_shutdown_threads(struct net *net); > > void nfsd_put(struct net *net); > @@ -506,6 +507,7 @@ extern void nfsd4_ssc_init_umount_work(struct nfsd_net *nn); > > extern void nfsd4_init_leases_net(struct nfsd_net *nn); > > +const char *nfsd4_op_name(unsigned opnum); > #else /* CONFIG_NFSD_V4 */ > static inline int nfsd4_is_junction(struct dentry *dentry) > { > diff --git a/fs/nfsd/nfssvc.c b/fs/nfsd/nfssvc.c > index 97830e28c140..e9e954b5ae47 100644 > --- a/fs/nfsd/nfssvc.c > +++ b/fs/nfsd/nfssvc.c > @@ -1057,6 +1057,8 @@ int nfsd_dispatch(struct svc_rqst *rqstp) > if (!proc->pc_decode(rqstp, &rqstp->rq_arg_stream)) > goto out_decode_err; > > + atomic_inc(&rqstp->rq_status_counter); > + Does this really have to be an atomic_t ? Seems like nfsd_dispatch is the only function updating it. You might need release semantics here and acquire semantics in nfsd_rpc_status_show(). I'd rather avoid a full-on atomic op in nfsd_dispatch() unless it's absolutely needed. Also, do you need to bump the rq_status_counter in the other RPC dispatch routines (lockd and nfs callback) too? > rp = NULL; > switch (nfsd_cache_lookup(rqstp, &rp)) { > case RC_DOIT: > @@ -1074,6 +1076,8 @@ int nfsd_dispatch(struct svc_rqst *rqstp) > if (!proc->pc_encode(rqstp, &rqstp->rq_res_stream)) > goto out_encode_err; > > + atomic_inc(&rqstp->rq_status_counter); > + > nfsd_cache_update(rqstp, rp, rqstp->rq_cachetype, statp + 1); > out_cached_reply: > return 1; > @@ -1149,3 +1153,121 @@ int nfsd_pool_stats_release(struct inode *inode, struct file *file) > mutex_unlock(&nfsd_mutex); > return ret; > } > + > +static int nfsd_rpc_status_show(struct seq_file *m, void *v) > +{ > + struct inode *inode = file_inode(m->file); > + struct nfsd_net *nn = net_generic(inode->i_sb->s_fs_info, nfsd_net_id); > + int i; > + > + rcu_read_lock(); > + > + for (i = 0; i < nn->nfsd_serv->sv_nrpools; i++) { > + struct svc_rqst *rqstp; > + > + list_for_each_entry_rcu(rqstp, > + &nn->nfsd_serv->sv_pools[i].sp_all_threads, > + rq_all) { > + struct nfsd_rpc_status_info { > + struct sockaddr daddr; > + struct sockaddr saddr; > + unsigned long rq_flags; > + __be32 rq_xid; > + u32 rq_prog; > + u32 rq_vers; > + const char *pc_name; > + ktime_t rq_stime; > + u32 opnum[NFSD_MAX_OPS_PER_COMPOUND]; /* NFSv4 compund */ > + } rqstp_info; > + unsigned int status_counter; > + char buf[RPC_MAX_ADDRBUFLEN]; > + int j, opcnt = 0; > + > + if (!test_bit(RQ_BUSY, &rqstp->rq_flags)) > + continue; > + > + status_counter = atomic_read(&rqstp->rq_status_counter); Neil said: > I suggest you add add a counter to the rqstp which is incremented from > even to odd after parsing a request - including he v4 parsing needed to > have a sable ->opcnt - and then incremented from odd to even when the > request is complete. > Then this code samples the counter, skips the rqst if the counter is > even, and resamples the counter after collecting the data. If it has > changed, the drop the record. I don't see a check if the status counter is even. Also, as above, I'm not sure atomic_read() is necessary here. Maybe just READ_ONCE() ? Neil, any thoughts? > + > + rqstp_info.rq_xid = rqstp->rq_xid; > + rqstp_info.rq_flags = rqstp->rq_flags; > + rqstp_info.rq_prog = rqstp->rq_prog; > + rqstp_info.rq_vers = rqstp->rq_vers; > + rqstp_info.pc_name = svc_proc_name(rqstp); > + rqstp_info.rq_stime = rqstp->rq_stime; > + memcpy(&rqstp_info.daddr, svc_daddr(rqstp), > + sizeof(struct sockaddr)); > + memcpy(&rqstp_info.saddr, svc_addr(rqstp), > + sizeof(struct sockaddr)); > + > +#ifdef CONFIG_NFSD_V4 > + if (rqstp->rq_vers == NFS4_VERSION && > + rqstp->rq_proc == NFSPROC4_COMPOUND) { > + /* NFSv4 compund */ > + struct nfsd4_compoundargs *args = rqstp->rq_argp; > + > + opcnt = args->opcnt; > + for (j = 0; j < opcnt; j++) { > + struct nfsd4_op *op = &args->ops[j]; > + > + rqstp_info.opnum[j] = op->opnum; > + } > + } > +#endif /* CONFIG_NFSD_V4 */ > + > + /* In order to detect if the RPC request is pending and > + * RPC info are stable we check if rq_status_counter > + * has been incremented during the handler processing. > + */ > + if (status_counter != atomic_read(&rqstp->rq_status_counter)) > + continue; > + > + seq_printf(m, > + "0x%08x, 0x%08lx, 0x%08x, NFSv%d, %s, %016lld,", > + be32_to_cpu(rqstp_info.rq_xid), > + rqstp_info.rq_flags, > + rqstp_info.rq_prog, > + rqstp_info.rq_vers, > + rqstp_info.pc_name, > + ktime_to_us(rqstp_info.rq_stime)); > + > + seq_printf(m, " %s,", > + __svc_print_addr(&rqstp_info.saddr, buf, > + sizeof(buf), false)); > + seq_printf(m, " %s,", > + __svc_print_addr(&rqstp_info.daddr, buf, > + sizeof(buf), false)); > + for (j = 0; j < opcnt; j++) > + seq_printf(m, " %s%s", > + nfsd4_op_name(rqstp_info.opnum[j]), > + j == opcnt - 1 ? "," : ""); > + seq_puts(m, "\n"); > + } > + } > + > + rcu_read_unlock(); > + > + return 0; > +} > + > +/** > + * nfsd_rpc_status_open - Atomically copy a write verifier The kdoc comment maybe was copied, pasted, and then not updated? > + * @inode: entry inode pointer. > + * @file: entry file pointer. > + * > + * This routine dumps pending RPC requests info queued into nfs server. > + */ > +int nfsd_rpc_status_open(struct inode *inode, struct file *file) > +{ > + struct nfsd_net *nn = net_generic(inode->i_sb->s_fs_info, nfsd_net_id); > + > + mutex_lock(&nfsd_mutex); > + if (!nn->nfsd_serv) { > + mutex_unlock(&nfsd_mutex); > + return -ENODEV; > + } > + > + svc_get(nn->nfsd_serv); > + mutex_unlock(&nfsd_mutex); > + > + return single_open(file, nfsd_rpc_status_show, inode->i_private); > +} > diff --git a/include/linux/sunrpc/svc.h b/include/linux/sunrpc/svc.h > index fe1394cc1371..cb516da9e270 100644 > --- a/include/linux/sunrpc/svc.h > +++ b/include/linux/sunrpc/svc.h > @@ -270,6 +270,7 @@ struct svc_rqst { > * net namespace > */ > void ** rq_lease_breaker; /* The v4 client breaking a lease */ > + atomic_t rq_status_counter; /* RPC processing counter */ > }; > > #define SVC_NET(rqst) (rqst->rq_xprt ? rqst->rq_xprt->xpt_net : rqst->rq_bc_net) > diff --git a/net/sunrpc/svc.c b/net/sunrpc/svc.c > index 587811a002c9..44eac83b35a1 100644 > --- a/net/sunrpc/svc.c > +++ b/net/sunrpc/svc.c > @@ -1629,7 +1629,7 @@ const char *svc_proc_name(const struct svc_rqst *rqstp) > return rqstp->rq_procinfo->pc_name; > return "unknown"; > } > - > +EXPORT_SYMBOL_GPL(svc_proc_name); > > /** > * svc_encode_result_payload - mark a range of bytes as a result payload > -- > 2.41.0 > -- Chuck Lever
