According to commit bbf2f098838a ("nfsd: Reset the boot verifier on
all write I/O errors"), the Linux NFS server forces all clients to
resend pending unstable writes if any server-side write or commit
operation encounters an error (say, ENOSPC). This is a rare and
quite exceptional event that could require administrative recovery
action, so it should be made trace-able. Example trace event:
nfsd-938 [002] 7174.945558: nfsd_writeverf_reset: boot_time= 61cc920d xid=0xdcd62036 error=-28 new verifier=0x08aecc6142515904
Signed-off-by: Chuck Lever <chuck.lever@xxxxxxxxxx>
---
fs/nfsd/trace.h | 28 ++++++++++++++++++++++++++++
fs/nfsd/vfs.c | 13 ++++++++++---
2 files changed, 38 insertions(+), 3 deletions(-)
diff --git a/fs/nfsd/trace.h b/fs/nfsd/trace.h
index 54a84b5f7e35..b6b25f0f67a5 100644
--- a/fs/nfsd/trace.h
+++ b/fs/nfsd/trace.h
@@ -564,6 +564,34 @@ DEFINE_EVENT(nfsd_net_class, nfsd_##name, \
DEFINE_NET_EVENT(grace_start);
DEFINE_NET_EVENT(grace_complete);
+TRACE_EVENT(nfsd_writeverf_reset,
+ TP_PROTO(
+ const struct nfsd_net *nn,
+ const struct svc_rqst *rqstp,
+ int error
+ ),
+ TP_ARGS(nn, rqstp, error),
+ TP_STRUCT__entry(
+ __field(unsigned long long, boot_time)
+ __field(u32, xid)
+ __field(int, error)
+ __array(unsigned char, verifier, NFS4_VERIFIER_SIZE)
+ ),
+ TP_fast_assign(
+ __entry->boot_time = nn->boot_time;
+ __entry->xid = be32_to_cpu(rqstp->rq_xid);
+ __entry->error = error;
+
+ /* avoid seqlock inside TP_fast_assign */
+ memcpy(__entry->verifier, nn->writeverf,
+ NFS4_VERIFIER_SIZE);
+ ),
+ TP_printk("boot_time=%16llx xid=0x%08x error=%d new verifier=0x%s",
+ __entry->boot_time, __entry->xid, __entry->error,
+ __print_hex_str(__entry->verifier, NFS4_VERIFIER_SIZE)
+ )
+);
+
TRACE_EVENT(nfsd_clid_cred_mismatch,
TP_PROTO(
const struct nfs4_client *clp,
diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c
index 49564457bd3d..e4e59e1660e1 100644
--- a/fs/nfsd/vfs.c
+++ b/fs/nfsd/vfs.c
@@ -553,14 +553,17 @@ __be32 nfsd4_clone_file_range(struct svc_rqst *rqstp,
if (!status)
status = commit_inode_metadata(file_inode(src));
if (status < 0) {
+ struct nfsd_net *nn = net_generic(nf_dst->nf_net,
+ nfsd_net_id);
+
trace_nfsd_clone_file_range_err(rqstp,
&nfsd4_get_cstate(rqstp)->save_fh,
src_pos,
&nfsd4_get_cstate(rqstp)->current_fh,
dst_pos,
count, status);
- nfsd_reset_write_verifier(net_generic(nf_dst->nf_net,
- nfsd_net_id));
+ nfsd_reset_write_verifier(nn);
+ trace_nfsd_writeverf_reset(nn, rqstp, status);
ret = nfserrno(status);
}
}
@@ -1017,6 +1020,7 @@ nfsd_vfs_write(struct svc_rqst *rqstp, struct svc_fh *fhp, struct nfsd_file *nf,
host_err = vfs_iter_write(file, &iter, &pos, flags);
if (host_err < 0) {
nfsd_reset_write_verifier(nn);
+ trace_nfsd_writeverf_reset(nn, rqstp, host_err);
goto out_nfserr;
}
*cnt = host_err;
@@ -1028,8 +1032,10 @@ nfsd_vfs_write(struct svc_rqst *rqstp, struct svc_fh *fhp, struct nfsd_file *nf,
if (stable && use_wgather) {
host_err = wait_for_concurrent_writes(file);
- if (host_err < 0)
+ if (host_err < 0) {
nfsd_reset_write_verifier(nn);
+ trace_nfsd_writeverf_reset(nn, rqstp, host_err);
+ }
}
out_nfserr:
@@ -1151,6 +1157,7 @@ nfsd_commit(struct svc_rqst *rqstp, struct svc_fh *fhp,
break;
default:
nfsd_reset_write_verifier(nn);
+ trace_nfsd_writeverf_reset(nn, rqstp, err2);
}
err = nfserrno(err2);
} else
