This is a note to let you know that I've just added the patch titled
NFSD: Set up an rhashtable for the filecache
to the 5.10-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
nfsd-set-up-an-rhashtable-for-the-filecache.patch
and it can be found in the queue-5.10 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 352a21396ff3ebe85b6e8f0d691ac65145561b89
Author: Chuck Lever <chuck.lever@xxxxxxxxxx>
Date: Fri Jul 8 14:26:23 2022 -0400
NFSD: Set up an rhashtable for the filecache
[ Upstream commit fc22945ecc2a0a028f3683115f98a922d506c284 ]
Add code to initialize and tear down an rhashtable. The rhashtable
is not used yet.
Reviewed-by: Jeff Layton <jlayton@xxxxxxxxxx>
Signed-off-by: Chuck Lever <chuck.lever@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/fs/nfsd/filecache.c b/fs/nfsd/filecache.c
index 33bb4d31b4972..95e7e15b567e2 100644
--- a/fs/nfsd/filecache.c
+++ b/fs/nfsd/filecache.c
@@ -12,6 +12,7 @@
#include <linux/fsnotify_backend.h>
#include <linux/fsnotify.h>
#include <linux/seq_file.h>
+#include <linux/rhashtable.h>
#include "vfs.h"
#include "nfsd.h"
@@ -62,6 +63,136 @@ static unsigned long nfsd_file_flags;
static struct fsnotify_group *nfsd_file_fsnotify_group;
static atomic_long_t nfsd_filecache_count;
static struct delayed_work nfsd_filecache_laundrette;
+static struct rhashtable nfsd_file_rhash_tbl
+ ____cacheline_aligned_in_smp;
+
+enum nfsd_file_lookup_type {
+ NFSD_FILE_KEY_INODE,
+ NFSD_FILE_KEY_FULL,
+};
+
+struct nfsd_file_lookup_key {
+ struct inode *inode;
+ struct net *net;
+ const struct cred *cred;
+ unsigned char need;
+ enum nfsd_file_lookup_type type;
+};
+
+/*
+ * The returned hash value is based solely on the address of an in-code
+ * inode, a pointer to a slab-allocated object. The entropy in such a
+ * pointer is concentrated in its middle bits.
+ */
+static u32 nfsd_file_inode_hash(const struct inode *inode, u32 seed)
+{
+ unsigned long ptr = (unsigned long)inode;
+ u32 k;
+
+ k = ptr >> L1_CACHE_SHIFT;
+ k &= 0x00ffffff;
+ return jhash2(&k, 1, seed);
+}
+
+/**
+ * nfsd_file_key_hashfn - Compute the hash value of a lookup key
+ * @data: key on which to compute the hash value
+ * @len: rhash table's key_len parameter (unused)
+ * @seed: rhash table's random seed of the day
+ *
+ * Return value:
+ * Computed 32-bit hash value
+ */
+static u32 nfsd_file_key_hashfn(const void *data, u32 len, u32 seed)
+{
+ const struct nfsd_file_lookup_key *key = data;
+
+ return nfsd_file_inode_hash(key->inode, seed);
+}
+
+/**
+ * nfsd_file_obj_hashfn - Compute the hash value of an nfsd_file
+ * @data: object on which to compute the hash value
+ * @len: rhash table's key_len parameter (unused)
+ * @seed: rhash table's random seed of the day
+ *
+ * Return value:
+ * Computed 32-bit hash value
+ */
+static u32 nfsd_file_obj_hashfn(const void *data, u32 len, u32 seed)
+{
+ const struct nfsd_file *nf = data;
+
+ return nfsd_file_inode_hash(nf->nf_inode, seed);
+}
+
+static bool
+nfsd_match_cred(const struct cred *c1, const struct cred *c2)
+{
+ int i;
+
+ if (!uid_eq(c1->fsuid, c2->fsuid))
+ return false;
+ if (!gid_eq(c1->fsgid, c2->fsgid))
+ return false;
+ if (c1->group_info == NULL || c2->group_info == NULL)
+ return c1->group_info == c2->group_info;
+ if (c1->group_info->ngroups != c2->group_info->ngroups)
+ return false;
+ for (i = 0; i < c1->group_info->ngroups; i++) {
+ if (!gid_eq(c1->group_info->gid[i], c2->group_info->gid[i]))
+ return false;
+ }
+ return true;
+}
+
+/**
+ * nfsd_file_obj_cmpfn - Match a cache item against search criteria
+ * @arg: search criteria
+ * @ptr: cache item to check
+ *
+ * Return values:
+ * %0 - Item matches search criteria
+ * %1 - Item does not match search criteria
+ */
+static int nfsd_file_obj_cmpfn(struct rhashtable_compare_arg *arg,
+ const void *ptr)
+{
+ const struct nfsd_file_lookup_key *key = arg->key;
+ const struct nfsd_file *nf = ptr;
+
+ switch (key->type) {
+ case NFSD_FILE_KEY_INODE:
+ if (nf->nf_inode != key->inode)
+ return 1;
+ break;
+ case NFSD_FILE_KEY_FULL:
+ if (nf->nf_inode != key->inode)
+ return 1;
+ if (nf->nf_may != key->need)
+ return 1;
+ if (nf->nf_net != key->net)
+ return 1;
+ if (!nfsd_match_cred(nf->nf_cred, key->cred))
+ return 1;
+ if (test_bit(NFSD_FILE_HASHED, &nf->nf_flags) == 0)
+ return 1;
+ break;
+ }
+ return 0;
+}
+
+static const struct rhashtable_params nfsd_file_rhash_params = {
+ .key_len = sizeof_field(struct nfsd_file, nf_inode),
+ .key_offset = offsetof(struct nfsd_file, nf_inode),
+ .head_offset = offsetof(struct nfsd_file, nf_rhash),
+ .hashfn = nfsd_file_key_hashfn,
+ .obj_hashfn = nfsd_file_obj_hashfn,
+ .obj_cmpfn = nfsd_file_obj_cmpfn,
+ /* Reduce resizing churn on light workloads */
+ .min_size = 512, /* buckets */
+ .automatic_shrinking = true,
+};
static void
nfsd_file_schedule_laundrette(void)
@@ -693,13 +824,18 @@ static const struct fsnotify_ops nfsd_file_fsnotify_ops = {
int
nfsd_file_cache_init(void)
{
- int ret = -ENOMEM;
+ int ret;
unsigned int i;
lockdep_assert_held(&nfsd_mutex);
if (test_and_set_bit(NFSD_FILE_CACHE_UP, &nfsd_file_flags) == 1)
return 0;
+ ret = rhashtable_init(&nfsd_file_rhash_tbl, &nfsd_file_rhash_params);
+ if (ret)
+ return ret;
+
+ ret = -ENOMEM;
nfsd_filecache_wq = alloc_workqueue("nfsd_filecache", 0, 0);
if (!nfsd_filecache_wq)
goto out;
@@ -777,6 +913,7 @@ nfsd_file_cache_init(void)
nfsd_file_hashtbl = NULL;
destroy_workqueue(nfsd_filecache_wq);
nfsd_filecache_wq = NULL;
+ rhashtable_destroy(&nfsd_file_rhash_tbl);
goto out;
}
@@ -902,6 +1039,7 @@ nfsd_file_cache_shutdown(void)
nfsd_file_hashtbl = NULL;
destroy_workqueue(nfsd_filecache_wq);
nfsd_filecache_wq = NULL;
+ rhashtable_destroy(&nfsd_file_rhash_tbl);
for_each_possible_cpu(i) {
per_cpu(nfsd_file_cache_hits, i) = 0;
@@ -913,26 +1051,6 @@ nfsd_file_cache_shutdown(void)
}
}
-static bool
-nfsd_match_cred(const struct cred *c1, const struct cred *c2)
-{
- int i;
-
- if (!uid_eq(c1->fsuid, c2->fsuid))
- return false;
- if (!gid_eq(c1->fsgid, c2->fsgid))
- return false;
- if (c1->group_info == NULL || c2->group_info == NULL)
- return c1->group_info == c2->group_info;
- if (c1->group_info->ngroups != c2->group_info->ngroups)
- return false;
- for (i = 0; i < c1->group_info->ngroups; i++) {
- if (!gid_eq(c1->group_info->gid[i], c2->group_info->gid[i]))
- return false;
- }
- return true;
-}
-
static struct nfsd_file *
nfsd_file_find_locked(struct inode *inode, unsigned int may_flags,
unsigned int hashval, struct net *net)
diff --git a/fs/nfsd/filecache.h b/fs/nfsd/filecache.h
index 82051e1b8420d..5cbfc61a7d7d9 100644
--- a/fs/nfsd/filecache.h
+++ b/fs/nfsd/filecache.h
@@ -29,6 +29,7 @@ struct nfsd_file_mark {
* never be dereferenced, only used for comparison.
*/
struct nfsd_file {
+ struct rhash_head nf_rhash;
struct hlist_node nf_node;
struct list_head nf_lru;
struct rcu_head nf_rcu;
