[PATCH v4 2/2] NFSD: add rpc_status entry in nfsd debug filesystem

Lorenzo Bianconi
2023-07-28T18:44:35Z

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@kernel.org>
---
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);
+
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);
+
+ 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
+ * @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