[PATCH v2 1/4] nfsd: nfsd_file cache entries should be per net namespace

Trond Myklebust
2019-09-02T17:06:28Z

Ensure that we can safely clear out the file cache entries when the
nfs server is shut down on a container. Otherwise, the file cache
may end up pinning the mounts.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
---
fs/nfsd/export.c | 2 +-
fs/nfsd/filecache.c | 33 +++++++++++++++++++++------------
fs/nfsd/filecache.h | 3 ++-
fs/nfsd/nfssvc.c | 1 +
4 files changed, 25 insertions(+), 14 deletions(-)

diff --git a/fs/nfsd/export.c b/fs/nfsd/export.c
index 052fac64b578..15422c951fd1 100644
--- a/fs/nfsd/export.c
+++ b/fs/nfsd/export.c
@@ -240,7 +240,7 @@ static void expkey_flush(void)
* destroyed while we're in the middle of flushing.
*/
mutex_lock(&nfsd_mutex);
- nfsd_file_cache_purge();
+ nfsd_file_cache_purge(current->nsproxy->net_ns);
mutex_unlock(&nfsd_mutex);
}

diff --git a/fs/nfsd/filecache.c b/fs/nfsd/filecache.c
index a2fcb251d2f6..d229fd3c825d 100644
--- a/fs/nfsd/filecache.c
+++ b/fs/nfsd/filecache.c
@@ -17,6 +17,7 @@
#include "vfs.h"
#include "nfsd.h"
#include "nfsfh.h"
+#include "netns.h"
#include "filecache.h"
#include "trace.h"

@@ -168,7 +169,8 @@ nfsd_file_mark_find_or_create(struct nfsd_file *nf)
}

static struct nfsd_file *
-nfsd_file_alloc(struct inode *inode, unsigned int may, unsigned int hashval)
+nfsd_file_alloc(struct inode *inode, unsigned int may, unsigned int hashval,
+ struct net *net)
{
struct nfsd_file *nf;

@@ -178,6 +180,7 @@ nfsd_file_alloc(struct inode *inode, unsigned int may, unsigned int hashval)
INIT_LIST_HEAD(&nf->nf_lru);
nf->nf_file = NULL;
nf->nf_cred = get_current_cred();
+ nf->nf_net = net;
nf->nf_flags = 0;
nf->nf_inode = inode;
nf->nf_hashval = hashval;
@@ -608,10 +611,11 @@ nfsd_file_cache_init(void)
* Note this can deadlock with nfsd_file_lru_cb.
*/
void
-nfsd_file_cache_purge(void)
+nfsd_file_cache_purge(struct net *net)
{
unsigned int i;
struct nfsd_file *nf;
+ struct hlist_node *next;
LIST_HEAD(dispose);
bool del;

@@ -619,10 +623,12 @@ nfsd_file_cache_purge(void)
return;

for (i = 0; i < NFSD_FILE_HASH_SIZE; i++) {
- spin_lock(&nfsd_file_hashtbl[i].nfb_lock);
- while(!hlist_empty(&nfsd_file_hashtbl[i].nfb_head)) {
- nf = hlist_entry(nfsd_file_hashtbl[i].nfb_head.first,
- struct nfsd_file, nf_node);
+ struct nfsd_fcache_bucket *nfb = &nfsd_file_hashtbl[i];
+
+ spin_lock(&nfb->nfb_lock);
+ hlist_for_each_entry_safe(nf, next, &nfb->nfb_head, nf_node) {
+ if (net && nf->nf_net != net)
+ continue;
del = nfsd_file_unhash_and_release_locked(nf, &dispose);

/*
@@ -631,7 +637,7 @@ nfsd_file_cache_purge(void)
*/
WARN_ON_ONCE(!del);
}
- spin_unlock(&nfsd_file_hashtbl[i].nfb_lock);
+ spin_unlock(&nfb->nfb_lock);
nfsd_file_dispose_list(&dispose);
}
}
@@ -650,7 +656,7 @@ nfsd_file_cache_shutdown(void)
* calling nfsd_file_cache_purge
*/
cancel_delayed_work_sync(&nfsd_filecache_laundrette);
- nfsd_file_cache_purge();
+ nfsd_file_cache_purge(NULL);
list_lru_destroy(&nfsd_file_lru);
rcu_barrier();
fsnotify_put_group(nfsd_file_fsnotify_group);
@@ -686,7 +692,7 @@ nfsd_match_cred(const struct cred *c1, const struct cred *c2)

static struct nfsd_file *
nfsd_file_find_locked(struct inode *inode, unsigned int may_flags,
- unsigned int hashval)
+ unsigned int hashval, struct net *net)
{
struct nfsd_file *nf;
unsigned char need = may_flags & NFSD_FILE_MAY_MASK;
@@ -697,6 +703,8 @@ nfsd_file_find_locked(struct inode *inode, unsigned int may_flags,
continue;
if (nf->nf_inode != inode)
continue;
+ if (nf->nf_net != net)
+ continue;
if (!nfsd_match_cred(nf->nf_cred, current_cred()))
continue;
if (nfsd_file_get(nf) != NULL)
@@ -739,6 +747,7 @@ nfsd_file_acquire(struct svc_rqst *rqstp, struct svc_fh *fhp,
unsigned int may_flags, struct nfsd_file **pnf)
{
__be32 status;
+ struct net *net = SVC_NET(rqstp);
struct nfsd_file *nf, *new;
struct inode *inode;
unsigned int hashval;
@@ -753,12 +762,12 @@ nfsd_file_acquire(struct svc_rqst *rqstp, struct svc_fh *fhp,
hashval = (unsigned int)hash_long(inode->i_ino, NFSD_FILE_HASH_BITS);
retry:
rcu_read_lock();
- nf = nfsd_file_find_locked(inode, may_flags, hashval);
+ nf = nfsd_file_find_locked(inode, may_flags, hashval, net);
rcu_read_unlock();
if (nf)
goto wait_for_construction;

- new = nfsd_file_alloc(inode, may_flags, hashval);
+ new = nfsd_file_alloc(inode, may_flags, hashval, net);
if (!new) {
trace_nfsd_file_acquire(rqstp, hashval, inode, may_flags,
NULL, nfserr_jukebox);
@@ -766,7 +775,7 @@ nfsd_file_acquire(struct svc_rqst *rqstp, struct svc_fh *fhp,
}

spin_lock(&nfsd_file_hashtbl[hashval].nfb_lock);
- nf = nfsd_file_find_locked(inode, may_flags, hashval);
+ nf = nfsd_file_find_locked(inode, may_flags, hashval, net);
if (nf == NULL)
goto open_file;
spin_unlock(&nfsd_file_hashtbl[hashval].nfb_lock);
diff --git a/fs/nfsd/filecache.h b/fs/nfsd/filecache.h
index 0c0c67166b87..851d9abf54c2 100644
--- a/fs/nfsd/filecache.h
+++ b/fs/nfsd/filecache.h
@@ -34,6 +34,7 @@ struct nfsd_file {
struct rcu_head nf_rcu;
struct file *nf_file;
const struct cred *nf_cred;
+ struct net *nf_net;
#define NFSD_FILE_HASHED (0)
#define NFSD_FILE_PENDING (1)
#define NFSD_FILE_BREAK_READ (2)
@@ -48,7 +49,7 @@ struct nfsd_file {
};

int nfsd_file_cache_init(void);
-void nfsd_file_cache_purge(void);
+void nfsd_file_cache_purge(struct net *);
void nfsd_file_cache_shutdown(void);
void nfsd_file_put(struct nfsd_file *nf);
struct nfsd_file *nfsd_file_get(struct nfsd_file *nf);
diff --git a/fs/nfsd/nfssvc.c b/fs/nfsd/nfssvc.c
index d02712ca2685..b944553c6927 100644
--- a/fs/nfsd/nfssvc.c
+++ b/fs/nfsd/nfssvc.c
@@ -387,6 +387,7 @@ static void nfsd_shutdown_net(struct net *net)
{
struct nfsd_net *nn = net_generic(net, nfsd_net_id);

+ nfsd_file_cache_purge(net);
nfs4_state_shutdown_net(net);
if (nn->lockd_up) {
lockd_down(net);
--
2.21.0