[for-6.16-final PATCH 5/9] Revert "nfs_localio: simplify interface to nfsd for getting nfsd_file"

Mike Snitzer
2025-07-14T03:14:08Z

This reverts commit aa79c438fda263372c63df2170bc4e4030bb68de.

Really nasty revert due to original series not being bisect safe.

Signed-off-by: Mike Snitzer <snitzer@kernel.org>
---
fs/nfs/localio.c | 31 +++++++++++++++++++++++++------
fs/nfs_common/nfslocalio.c | 3 +--
fs/nfsd/localio.c | 37 ++++---------------------------------
include/linux/nfslocalio.h | 6 ++++--
4 files changed, 34 insertions(+), 43 deletions(-)

diff --git a/fs/nfs/localio.c b/fs/nfs/localio.c
index ef12dd279539..86df8d2cd22e 100644
--- a/fs/nfs/localio.c
+++ b/fs/nfs/localio.c
@@ -209,6 +209,11 @@ void nfs_local_probe_async(struct nfs_client *clp)
}
EXPORT_SYMBOL_GPL(nfs_local_probe_async);

+static inline struct nfsd_file *nfs_local_file_get(struct nfsd_file *nf)
+{
+ return nfs_to->nfsd_file_get_local(nf);
+}
+
static inline void nfs_local_file_put(struct nfsd_file *nf)
{
nfs_to_nfsd_file_put_local(nf);
@@ -223,13 +228,12 @@ static inline void nfs_local_file_put(struct nfsd_file *nf)
static struct nfsd_file *
__nfs_local_open_fh(struct nfs_client *clp, const struct cred *cred,
struct nfs_fh *fh, struct nfs_file_localio *nfl,
- struct nfsd_file __rcu **pnf,
const fmode_t mode)
{
struct nfsd_file *localio;

localio = nfs_open_local_fh(&clp->cl_uuid, clp->cl_rpcclient,
- cred, fh, nfl, pnf, mode);
+ cred, fh, nfl, mode);
if (IS_ERR(localio)) {
int status = PTR_ERR(localio);
trace_nfs_local_open_fh(fh, mode, status);
@@ -256,7 +260,7 @@ nfs_local_open_fh(struct nfs_client *clp, const struct cred *cred,
struct nfs_fh *fh, struct nfs_file_localio *nfl,
const fmode_t mode)
{
- struct nfsd_file *nf, __rcu **pnf;
+ struct nfsd_file *nf, *new, __rcu **pnf;

if (!nfs_server_is_local(clp))
return NULL;
@@ -268,9 +272,24 @@ nfs_local_open_fh(struct nfs_client *clp, const struct cred *cred,
else
pnf = &nfl->ro_file;

- nf = __nfs_local_open_fh(clp, cred, fh, nfl, pnf, mode);
- if (IS_ERR(nf))
- return NULL;
+ new = NULL;
+ rcu_read_lock();
+ nf = rcu_dereference(*pnf);
+ if (!nf) {
+ rcu_read_unlock();
+ new = __nfs_local_open_fh(clp, cred, fh, nfl, mode);
+ if (IS_ERR(new))
+ return NULL;
+ rcu_read_lock();
+ /* try to swap in the pointer */
+ nf = unrcu_pointer(cmpxchg(pnf, NULL, RCU_INITIALIZER(new)));
+ if (!nf)
+ swap(nf, new);
+ }
+ nf = nfs_local_file_get(nf);
+ rcu_read_unlock();
+ if (new)
+ nfs_to_nfsd_file_put_local(new);
return nf;
}
EXPORT_SYMBOL_GPL(nfs_local_open_fh);
diff --git a/fs/nfs_common/nfslocalio.c b/fs/nfs_common/nfslocalio.c
index 503f85f64b76..f6821b2c87a2 100644
--- a/fs/nfs_common/nfslocalio.c
+++ b/fs/nfs_common/nfslocalio.c
@@ -237,7 +237,6 @@ static void nfs_uuid_add_file(nfs_uuid_t *nfs_uuid, struct nfs_file_localio *nfl
struct nfsd_file *nfs_open_local_fh(nfs_uuid_t *uuid,
struct rpc_clnt *rpc_clnt, const struct cred *cred,
const struct nfs_fh *nfs_fh, struct nfs_file_localio *nfl,
- struct nfsd_file __rcu **pnf,
const fmode_t fmode)
{
struct net *net;
@@ -262,7 +261,7 @@ struct nfsd_file *nfs_open_local_fh(nfs_uuid_t *uuid,
rcu_read_unlock();
/* We have an implied reference to net thanks to nfsd_net_try_get */
localio = nfs_to->nfsd_open_local_fh(net, uuid->dom, rpc_clnt,
- cred, nfs_fh, pnf, fmode);
+ cred, nfs_fh, fmode);
nfs_to_nfsd_net_put(net);
if (!IS_ERR(localio))
nfs_uuid_add_file(uuid, nfl);
diff --git a/fs/nfsd/localio.c b/fs/nfsd/localio.c
index 80d9ff6608a7..40998283b858 100644
--- a/fs/nfsd/localio.c
+++ b/fs/nfsd/localio.c
@@ -32,7 +32,6 @@
* @rpc_clnt: rpc_clnt that the client established
* @cred: cred that the client established
* @nfs_fh: filehandle to lookup
- * @nfp: place to find the nfsd_file, or store it if it was non-NULL
* @fmode: fmode_t to use for open
*
* This function maps a local fh to a path on a local filesystem.
@@ -43,11 +42,10 @@
* set. Caller (NFS client) is responsible for calling nfsd_net_put and
* nfsd_file_put (via nfs_to_nfsd_file_put_local).
*/
-static struct nfsd_file *
+struct nfsd_file *
nfsd_open_local_fh(struct net *net, struct auth_domain *dom,
struct rpc_clnt *rpc_clnt, const struct cred *cred,
- const struct nfs_fh *nfs_fh, struct nfsd_file __rcu **pnf,
- const fmode_t fmode)
+ const struct nfs_fh *nfs_fh, const fmode_t fmode)
{
int mayflags = NFSD_MAY_LOCALIO;
struct svc_cred rq_cred;
@@ -61,12 +59,6 @@ nfsd_open_local_fh(struct net *net, struct auth_domain *dom,
if (!nfsd_net_try_get(net))
return ERR_PTR(-ENXIO);

- rcu_read_lock();
- localio = nfsd_file_get(rcu_dereference(*pnf));
- rcu_read_unlock();
- if (localio)
- return localio;
-
/* nfs_fh -> svc_fh */
fh_init(&fh, NFS4_FHSIZE);
fh.fh_handle.fh_size = nfs_fh->size;
@@ -88,33 +80,12 @@ nfsd_open_local_fh(struct net *net, struct auth_domain *dom,
if (rq_cred.cr_group_info)
put_group_info(rq_cred.cr_group_info);

- if (!IS_ERR(localio)) {
- struct nfsd_file *new;
- if (!nfsd_net_try_get(net)) {
- nfsd_file_put(localio);
- nfsd_net_put(net);
- return ERR_PTR(-ENXIO);
- }
- nfsd_file_get(localio);
- again:
- new = unrcu_pointer(cmpxchg(pnf, NULL, RCU_INITIALIZER(localio)));
- if (new) {
- /* Some other thread installed an nfsd_file */
- if (nfsd_file_get(new) == NULL)
- goto again;
- /*
- * Drop the ref we were going to install and the
- * one we were going to return.
- */
- nfsd_file_put(localio);
- nfsd_file_put(localio);
- localio = new;
- }
- } else
+ if (IS_ERR(localio))
nfsd_net_put(net);

return localio;
}
+EXPORT_SYMBOL_GPL(nfsd_open_local_fh);

static const struct nfsd_localio_operations nfsd_localio_ops = {
.nfsd_net_try_get = nfsd_net_try_get,
diff --git a/include/linux/nfslocalio.h b/include/linux/nfslocalio.h
index 453d9de3d70b..c3f34bae60e1 100644
--- a/include/linux/nfslocalio.h
+++ b/include/linux/nfslocalio.h
@@ -50,6 +50,10 @@ void nfs_localio_invalidate_clients(struct list_head *nn_local_clients,
spinlock_t *nn_local_clients_lock);

/* localio needs to map filehandle -> struct nfsd_file */
+extern struct nfsd_file *
+nfsd_open_local_fh(struct net *, struct auth_domain *, struct rpc_clnt *,
+ const struct cred *, const struct nfs_fh *,
+ const fmode_t) __must_hold(rcu);
void nfs_close_local_fh(struct nfs_file_localio *);

struct nfsd_localio_operations {
@@ -60,7 +64,6 @@ struct nfsd_localio_operations {
struct rpc_clnt *,
const struct cred *,
const struct nfs_fh *,
- struct nfsd_file __rcu **,
const fmode_t);
struct net *(*nfsd_file_put_local)(struct nfsd_file *);
struct nfsd_file *(*nfsd_file_get_local)(struct nfsd_file *);
@@ -73,7 +76,6 @@ extern const struct nfsd_localio_operations *nfs_to;
struct nfsd_file *nfs_open_local_fh(nfs_uuid_t *,
struct rpc_clnt *, const struct cred *,
const struct nfs_fh *, struct nfs_file_localio *,
- struct nfsd_file __rcu **pnf,
const fmode_t);

static inline void nfs_to_nfsd_net_put(struct net *net)
--
2.44.0