[PATCH v2 31/31] nfsd: convert dprintks in check_export() to tracepoints

Jeff Layton
2026-01-19T16:31:03Z

Get rid of the dprintk messages in check_export(). Instead add new
tracepoints that show the terminal inode and the flags.

Signed-off-by: Jeff Layton <jlayton@kernel.org>
---
fs/nfsd/export.c | 11 ++++++-----
fs/nfsd/trace.h | 52 ++++++++++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 58 insertions(+), 5 deletions(-)

diff --git a/fs/nfsd/export.c b/fs/nfsd/export.c
index bc703cf58bfa210c7c57d49f22f15bc10d7cfc91..3cc336b953b38573966c43000f31cd341380837b 100644
--- a/fs/nfsd/export.c
+++ b/fs/nfsd/export.c
@@ -435,31 +435,32 @@ static int check_export(const struct path *path, int *flags, unsigned char *uuid
if (!(inode->i_sb->s_type->fs_flags & FS_REQUIRES_DEV) &&
!(*flags & NFSEXP_FSID) &&
uuid == NULL) {
- dprintk("exp_export: export of non-dev fs without fsid\n");
+ trace_nfsd_check_export_need_fsid(inode, *flags);
return -EINVAL;
}

if (!exportfs_can_decode_fh(inode->i_sb->s_export_op)) {
- dprintk("exp_export: export of invalid fs type.\n");
+ trace_nfsd_check_export_invalid_fstype(inode, *flags);
return -EINVAL;
}

if (!(inode->i_sb->s_export_op->flags & EXPORT_OP_STABLE_HANDLES)) {
- dprintk("%s: fs does not provide stable filehandles!\n", __func__);
+ trace_nfsd_check_export_no_stable_fh(inode, *flags);
return -EINVAL;
}

if (is_idmapped_mnt(path->mnt)) {
dprintk("exp_export: export of idmapped mounts not yet supported.\n");
+ trace_nfsd_check_export_idmapped(inode, *flags);
return -EINVAL;
}

if (inode->i_sb->s_export_op->flags & EXPORT_OP_NOSUBTREECHK &&
!(*flags & NFSEXP_NOSUBTREECHECK)) {
- dprintk("%s: %s does not support subtree checking!\n",
- __func__, inode->i_sb->s_type->name);
+ trace_nfsd_check_export_subtree(inode, *flags);
return -EINVAL;
}
+ trace_nfsd_check_export_success(inode, *flags);
return 0;
}

diff --git a/fs/nfsd/trace.h b/fs/nfsd/trace.h
index 5ae2a611e57f4b4e51a4d9eb6e0fccb66ad8d288..e3f5fe1181b605b34cb70d53f32739c3ef9b82f6 100644
--- a/fs/nfsd/trace.h
+++ b/fs/nfsd/trace.h
@@ -339,6 +339,58 @@ DEFINE_EVENT_CONDITION(nfsd_fh_err_class, nfsd_##name, \
DEFINE_NFSD_FH_ERR_EVENT(set_fh_dentry_badexport);
DEFINE_NFSD_FH_ERR_EVENT(set_fh_dentry_badhandle);

+#define show_export_flags(val) \
+ __print_flags(val, "|", \
+ { NFSEXP_READONLY, "READONLY" }, \
+ { NFSEXP_INSECURE_PORT, "INSECURE" }, \
+ { NFSEXP_ROOTSQUASH, "ROOTSQUASH" }, \
+ { NFSEXP_ALLSQUASH, "ALLSQUASH" }, \
+ { NFSEXP_ASYNC, "ASYNC" }, \
+ { NFSEXP_GATHERED_WRITES, "GATHERED_WRITES" }, \
+ { NFSEXP_NOREADDIRPLUS, "NOREADDIRPLUS" }, \
+ { NFSEXP_SECURITY_LABEL, "SECURITY_LABEL" }, \
+ { NFSEXP_NOHIDE, "NOHIDE" }, \
+ { NFSEXP_NOSUBTREECHECK, "NOSUBTREECHECK" }, \
+ { NFSEXP_NOAUTHNLM, "NOAUTHNLM" }, \
+ { NFSEXP_MSNFS, "MSNFS" }, \
+ { NFSEXP_FSID, "FSID" }, \
+ { NFSEXP_CROSSMOUNT, "CROSSMOUNT" }, \
+ { NFSEXP_NOACL, "NOACL" }, \
+ { NFSEXP_V4ROOT, "V4ROOT" }, \
+ { NFSEXP_PNFS, "PNFS" })
+
+DECLARE_EVENT_CLASS(nfsd_check_export_class,
+ TP_PROTO(const struct inode *inode,
+ int flags),
+ TP_ARGS(inode, flags),
+ TP_STRUCT__entry(
+ __field(dev_t, dev)
+ __field(ino_t, ino)
+ __field(int, flags)
+ ),
+ TP_fast_assign(
+ __entry->dev = inode->i_sb->s_dev;
+ __entry->ino = inode->i_ino;
+ __entry->flags = flags;
+ ),
+ TP_printk("dev=%u:%u:%lu flags=%s",
+ MAJOR(__entry->dev), MINOR(__entry->dev),
+ __entry->ino, show_export_flags(__entry->flags))
+)
+
+#define DEFINE_NFSD_CHECK_EXPORT_EVENT(name) \
+DEFINE_EVENT(nfsd_check_export_class, nfsd_check_export_##name, \
+ TP_PROTO(const struct inode *inode, \
+ int flags), \
+ TP_ARGS(inode, flags))
+
+DEFINE_NFSD_CHECK_EXPORT_EVENT(need_fsid);
+DEFINE_NFSD_CHECK_EXPORT_EVENT(invalid_fstype);
+DEFINE_NFSD_CHECK_EXPORT_EVENT(no_stable_fh);
+DEFINE_NFSD_CHECK_EXPORT_EVENT(idmapped);
+DEFINE_NFSD_CHECK_EXPORT_EVENT(subtree);
+DEFINE_NFSD_CHECK_EXPORT_EVENT(success);
+
TRACE_EVENT(nfsd_exp_find_key,
TP_PROTO(const struct svc_expkey *key,
int status),

--
2.52.0